Modeling personnel turnover in the parametric organization

NASA Technical Reports Server (NTRS)

Dean, Edwin B.

1991-01-01

A model is developed for simulating the dynamics of a newly formed organization, credible during all phases of organizational development. The model development process is broken down into the activities of determining the tasks required for parametric cost analysis (PCA), determining the skills required for each PCA task, determining the skills available in the applicant marketplace, determining the structure of the model, implementing the model, and testing it. The model, parameterized by the likelihood of job function transition, has demonstrated by the capability to represent the transition of personnel across functional boundaries within a parametric organization using a linear dynamical system, and the ability to predict required staffing profiles to meet functional needs at the desired time. The model can be extended by revisions of the state and transition structure to provide refinements in functional definition for the parametric and extended organization.

Creating Clay Models of a Human Torso as an Alternative to Dissection

ERIC Educational Resources Information Center

Shipley, Gwendolyn

2010-01-01

Instead of dissecting animals, students create small clay models of human internal organs to demonstrate their understanding of the positioning and interlocking shapes of the organs. Not only is this approach more environmentally friendly, it also forces them to learn human anatomy--which is more relevant to them than the anatomy of other…

Computing chemical organizations in biological networks.

PubMed

Centler, Florian; Kaleta, Christoph; di Fenizio, Pietro Speroni; Dittrich, Peter

2008-07-15

Novel techniques are required to analyze computational models of intracellular processes as they increase steadily in size and complexity. The theory of chemical organizations has recently been introduced as such a technique that links the topology of biochemical reaction network models to their dynamical repertoire. The network is decomposed into algebraically closed and self-maintaining subnetworks called organizations. They form a hierarchy representing all feasible system states including all steady states. We present three algorithms to compute the hierarchy of organizations for network models provided in SBML format. Two of them compute the complete organization hierarchy, while the third one uses heuristics to obtain a subset of all organizations for large models. While the constructive approach computes the hierarchy starting from the smallest organization in a bottom-up fashion, the flux-based approach employs self-maintaining flux distributions to determine organizations. A runtime comparison on 16 different network models of natural systems showed that none of the two exhaustive algorithms is superior in all cases. Studying a 'genome-scale' network model with 762 species and 1193 reactions, we demonstrate how the organization hierarchy helps to uncover the model structure and allows to evaluate the model's quality, for example by detecting components and subsystems of the model whose maintenance is not explained by the model. All data and a Java implementation that plugs into the Systems Biology Workbench is available from http://www.minet.uni-jena.de/csb/prj/ot/tools.

Breast Imaging: A Paradigm for Accountable Care Organizations.

PubMed

Parikh, Jay R; Yang, Wei T

2016-02-01

Accountable care organizations (ACOs) are being promoted by the Centers of Medicare Services as alternative payment models for radiology reimbursement. Because of its clinical orientation, focus on prevention, standardized reporting, quality orientation through mandatory accreditation, and value demonstration through established outcome metrics, breast imaging offers a unique paradigm for the ACO model in radiology. In radiology, breast imaging represents the paradigm for ACOs.

Compound prioritization methods increase rates of chemical probe discovery in model organisms

PubMed Central

Wallace, Iain M; Urbanus, Malene L; Luciani, Genna M; Burns, Andrew R; Han, Mitchell KL; Wang, Hao; Arora, Kriti; Heisler, Lawrence E; Proctor, Michael; St. Onge, Robert P; Roemer, Terry; Roy, Peter J; Cummins, Carolyn L; Bader, Gary D; Nislow, Corey; Giaever, Guri

2011-01-01

SUMMARY Pre-selection of compounds that are more likely to induce a phenotype can increase the efficiency and reduce the costs for model organism screening. To identify such molecules, we screened ~81,000 compounds in S. cerevisiae and identified ~7,500 that inhibit cell growth. Screening these growth-inhibitory molecules across a diverse panel of model organisms resulted in an increased phenotypic hit-rate. This data was used to build a model to predict compounds that inhibit yeast growth. Empirical and in silico application of the model enriched the discovery of bioactive compounds in diverse model organisms. To demonstrate the potential of these molecules as lead chemical probes we used chemogenomic profiling in yeast and identified specific inhibitors of lanosterol synthase and of stearoyl-CoA 9-desaturase. As community resources, the ~7,500 growth-inhibitory molecules has been made commercially available and the computational model and filter used are provided. PMID:22035796

Generation and mobility of radon in soil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rose, A.W.; Jester, W.A.; Ciolkosz, E.J.

This study has confirmed large seasonal and daily variations of Rn in soil gas, developed models for the effects of temperature and moisture on air-water Rn partition, inhibited Rn diffusion from wet soil into sparse large air-filled pores and effects of diffusion into bedrock, demonstrated that organic matter is a major host for 226Ra in soils and that organic-bound Ra largely determines the proportion of 222Rn emanated to pore space, shown that in contrast 220Rn is emanated mainly from 224Ra in Fe-oxides, detected significant disequilibrium between 226Ra and 238U in organic matter and in some recent glacial soils, demonstrated bymore » computer models that air convection driven by temperature differences is expected in moderately permeable soils on hillsides.« less

Generation and mobility of radon in soil. Technical report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rose, A.W.; Jester, W.A.; Ciolkosz, E.J.

This study has confirmed large seasonal and daily variations of Rn in soil gas, developed models for the effects of temperature and moisture on air-water Rn partition, inhibited Rn diffusion from wet soil into sparse large air-filled pores and effects of diffusion into bedrock, demonstrated that organic matter is a major host for 226Ra in soils and that organic-bound Ra largely determines the proportion of 222Rn emanated to pore space, shown that in contrast 220Rn is emanated mainly from 224Ra in Fe-oxides, detected significant disequilibrium between 226Ra and 238U in organic matter and in some recent glacial soils, demonstrated bymore » computer models that air convection driven by temperature differences is expected in moderately permeable soils on hillsides.« less

Uniform neural tissue models produced on synthetic hydrogels using standard culture techniques.

PubMed

Barry, Christopher; Schmitz, Matthew T; Propson, Nicholas E; Hou, Zhonggang; Zhang, Jue; Nguyen, Bao K; Bolin, Jennifer M; Jiang, Peng; McIntosh, Brian E; Probasco, Mitchell D; Swanson, Scott; Stewart, Ron; Thomson, James A; Schwartz, Michael P; Murphy, William L

2017-11-01

The aim of the present study was to test sample reproducibility for model neural tissues formed on synthetic hydrogels. Human embryonic stem (ES) cell-derived precursor cells were cultured on synthetic poly(ethylene glycol) (PEG) hydrogels to promote differentiation and self-organization into model neural tissue constructs. Neural progenitor, vascular, and microglial precursor cells were combined on PEG hydrogels to mimic developmental timing, which produced multicomponent neural constructs with 3D neuronal and glial organization, organized vascular networks, and microglia with ramified morphologies. Spearman's rank correlation analysis of global gene expression profiles and a comparison of coefficient of variation for expressed genes demonstrated that replicate neural constructs were highly uniform to at least day 21 for samples from independent experiments. We also demonstrate that model neural tissues formed on PEG hydrogels using a simplified neural differentiation protocol correlated more strongly to in vivo brain development than samples cultured on tissue culture polystyrene surfaces alone. These results provide a proof-of-concept demonstration that 3D cellular models that mimic aspects of human brain development can be produced from human pluripotent stem cells with high sample uniformity between experiments by using standard culture techniques, cryopreserved cell stocks, and a synthetic extracellular matrix. Impact statement Pluripotent stem (PS) cells have been characterized by an inherent ability to self-organize into 3D "organoids" resembling stomach, intestine, liver, kidney, and brain tissues, offering a potentially powerful tool for modeling human development and disease. However, organoid formation must be quantitatively reproducible for applications such as drug and toxicity screening. Here, we report a strategy to produce uniform neural tissue constructs with reproducible global gene expression profiles for replicate samples from multiple experiments.

A kinetic Monte Carlo model with improved charge injection model for the photocurrent characteristics of organic solar cells

NASA Astrophysics Data System (ADS)

Kipp, Dylan; Ganesan, Venkat

2013-06-01

We develop a kinetic Monte Carlo model for photocurrent generation in organic solar cells that demonstrates improved agreement with experimental illuminated and dark current-voltage curves. In our model, we introduce a charge injection rate prefactor to correct for the electrode grid-size and electrode charge density biases apparent in the coarse-grained approximation of the electrode as a grid of single occupancy, charge-injecting reservoirs. We use the charge injection rate prefactor to control the portion of dark current attributed to each of four kinds of charge injection. By shifting the dark current between electrode-polymer pairs, we align the injection timescales and expand the applicability of the method to accommodate ohmic energy barriers. We consider the device characteristics of the ITO/PEDOT/PSS:PPDI:PBTT:Al system and demonstrate the manner in which our model captures the device charge densities unique to systems with small injection energy barriers. To elucidate the defining characteristics of our model, we first demonstrate the manner in which charge accumulation and band bending affect the shape and placement of the various current-voltage regimes. We then discuss the influence of various model parameters upon the current-voltage characteristics.

BIOPLUME MODEL FOR CONTAMINANT TRANSPORT AFFECTED BY OXYGEN LIMITED BIODEGRADATION

EPA Science Inventory

Many of the organic pollutants entering ground water are potentially biodegradable in the subsurface. This potential has been demonstrated in aquifers contaminated by wood-creosoting process wastes. The persistence of many of these organic compounds in the subsurface indicated ...

Molecular and Cellular Interactions between Mother and Fetus. Pregnancy as a Rejuvenating Factor.

PubMed

Popkov, V A; Silachev, D N; Jankauskas, S S; Zorova, L D; Pevzner, I B; Babenko, V A; Plotnikov, E Y; Zorov, D B

2016-12-01

Aging is associated with a decline of various body functions, including ability to regenerate. Over recent decades, it has been demonstrated that some of these changes could be reversed in response to factors originating from a young organism, for example, fetal stem cells or "young blood" in models of heterochronic parabiosis. Pregnancy might be considered as parabiotic model of the interaction between two organisms of different age. In this work, we analyzed and summarized data on the effects of pregnancy on the maternal organism that confirm the hypothesis that pregnancy rejuvenates the mother's organism or slows its aging.

Toward a Theory of Variation in the Organization of the Word Reading System

ERIC Educational Resources Information Center

Rueckl, Jay G.

2016-01-01

The strategy underlying most computational models of word reading is to specify the organization of the reading system--its architecture and the processes and representations it employs--and to demonstrate that this organization would give rise to the behavior observed in word reading tasks. This approach fails to adequately address the variation…

Discrete element modeling of microstructure of nacre

NASA Astrophysics Data System (ADS)

Chandler, Mei Qiang; Cheng, Jing-Ru C.

2018-04-01

The microstructure of nacre consists of polygon-shaped aragonite mineral tablets bonded by very thin layers of organic materials and is organized in a brick-mortar morphology. In this research, the discrete element method was utilized to model this structure. The aragonite mineral tablets were modeled with three-dimensional polygon particles generated by the Voronoi tessellation method to represent the Voronoi-like patterns of mineral tablets assembly observed in experiments. The organic matrix was modeled with a group of spring elements. The constitutive relations of the spring elements were inspired from the experimental results of organic molecules from the literature. The mineral bridges were modeled with simple elastic bonds with the parameters based on experimental data from the literature. The bulk stress-strain responses from the models agreed well with experimental results. The model results show that the mineral bridges play important roles in providing the stiffness and yield strength for the nacre, while the organic matrix in providing the ductility for the nacre. This work demonstrated the suitability of particle methods for modeling microstructures of nacre.

Elucidating the Role of Electron Shuttles in Reductive Transformations in Anaerobic Sediments

EPA Science Inventory

Model studies have demonstrated that electron shuttles (ES) such as dissolved organic matter (DOM) can participate in the reduction of organic contaminants; however, much uncertainty exists concerning the significance of this solution phase pathway for contaminant reduction in na...

A human osteoarthritis osteochondral organ culture model for cartilage tissue engineering.

PubMed

Yeung, P; Zhang, W; Wang, X N; Yan, C H; Chan, B P

2018-04-01

In vitro human osteoarthritis (OA)-mimicking models enabling pathophysiological studies and evaluation of emerging therapies such as cartilage tissue engineering are of great importance. We describe the development and characterization of a human OA osteochondral organ culture. We also apply this model for evaluation of the phenotype maintenance of a human MSC derived engineered cartilage, as an example of emerging therapeutics, under long term exposure to the OA-mimicking environment. We also test the sensitivity of the model to a series of external factors and a potential disease-modifying agent, in terms of chondrogenic phenotype maintenance of the engineered cartilage, under OA-mimicking environment. Excised joint tissues from total knee replacement surgeries were carved into numerous miniaturized and standardized osteochondral plugs for subsequent OA organ culture. The organ cultures were characterized in detail before being co-cultured with a tissue engineered cartilage. The chondrogenic phenotype of the tissue engineered cartilage co-cultured in long term up to 8 weeks under this OA-mimicking microenvironment was evaluated. Using the same co-culture model, we also screened for a number of biomimetic environmental factors, including oxygen tension, the presence of serum and the application of compression loading. Finally, we studied the effect of a matrix metalloprotease inhibitor, as an example of potential disease-modifying agents, on the co-cultured engineered cartilage. We demonstrate that cells in the OA organ culture were viable while both the typical chondrogenic phenotype and the characteristic OA phenotype were maintained for long period of time. We then demonstrate that upon co-culture with the OA-mimicking organ culture, the engineered cartilage initially exhibited a more fibrocartilage phenotype but progressively reverted back to the chondrogenic phenotype upon long term co-culture up to 8 weeks. The engineered cartilage was also found to be sensitive to all biomimetic environmental factors screened (oxygen tension, serum and compression). Moreover, under the effect of a MMP inhibitor, the chondrogenic phenotype of engineered cartilage was better maintained. We demonstrated the development of a human OA osteochondral organ culture and tested the feasibility and potential of using this model as an in vitro evaluation tool for emerging cartilage therapies. Copyright © 2018 Elsevier Ltd. All rights reserved.

[Study on a new prevention and control model on soil-borne parasitic diseases in rural areas of China].

PubMed

Li, Xue-Ming; Chen, Ying-Dan; Xu, Long-Qi; Zhou, Chang-Hai; Ou-Yang, Yi; Lin, Rui; Yang, Fang-Fang; Zhang, Xiao-Juan; Wang, Ge; Liu, Teng; Wang, Jing

2011-12-01

To explore a new prevention and control model on soil-borne parasitic diseases in rural areas of China. Eight provinces and autonomous regions were selected in China as demonstration areas implementing integrated control on soil-borne parasitic diseases. The integrated control measures included authority organization and harmonization, health education, deworming, and environment modification. After three years, the infection rates of soil-borne parasitic diseases were significantly decreased in these areas. There were three safe guard and organization modes, three health education modes, four mass worming medication modes, and two modes of water, toilet and environment changes. The work in the various demonstration areas was summarized which pointed out a new model with efficiency and local characteristics on soil-borne parasitic disease prevention and control.

Chemical ageing and transformation of diffusivity in semi-solid multi-component organic aerosol particles

NASA Astrophysics Data System (ADS)

Pfrang, C.; Shiraiwa, M.; Pöschl, U.

2011-04-01

Recent experimental evidence underlines the importance of reduced diffusivity in amorphous semi-solid or glassy atmospheric aerosols. This paper investigates the impact of diffusivity on the ageing of multi-component reactive organic particles representative of atmospheric cooking aerosols. We apply and extend the recently developed KM-SUB model in a study of a 12-component mixture containing oleic and palmitoleic acids. We demonstrate that changes in the diffusivity may explain the evolution of chemical loss rates in ageing semi-solid particles, and we resolve surface and bulk processes under transient reaction conditions considering diffusivities altered by oligomerisation. This new model treatment allows prediction of the ageing of mixed organic multi-component aerosols over atmospherically relevant time scales and conditions. We illustrate the impact of changing diffusivity on the chemical half-life of reactive components in semi-solid particles, and we demonstrate how solidification and crust formation at the particle surface can affect the chemical transformation of organic aerosols.

Chemical ageing and transformation of diffusivity in semi-solid multi-component organic aerosol particles

NASA Astrophysics Data System (ADS)

Pfrang, C.; Shiraiwa, M.; Pöschl, U.

2011-07-01

Recent experimental evidence underlines the importance of reduced diffusivity in amorphous semi-solid or glassy atmospheric aerosols. This paper investigates the impact of diffusivity on the ageing of multi-component reactive organic particles approximating atmospheric cooking aerosols. We apply and extend the recently developed KM-SUB model in a study of a 12-component mixture containing oleic and palmitoleic acids. We demonstrate that changes in the diffusivity may explain the evolution of chemical loss rates in ageing semi-solid particles, and we resolve surface and bulk processes under transient reaction conditions considering diffusivities altered by oligomerisation. This new model treatment allows prediction of the ageing of mixed organic multi-component aerosols over atmospherically relevant timescales and conditions. We illustrate the impact of changing diffusivity on the chemical half-life of reactive components in semi-solid particles, and we demonstrate how solidification and crust formation at the particle surface can affect the chemical transformation of organic aerosols.

Tenax extraction as a simple approach to improve environmental risk assessments.

PubMed

Harwood, Amanda D; Nutile, Samuel A; Landrum, Peter F; Lydy, Michael J

2015-07-01

It is well documented that using exhaustive chemical extractions is not an effective means of assessing exposure of hydrophobic organic compounds in sediments and that bioavailability-based techniques are an improvement over traditional methods. One technique that has shown special promise as a method for assessing the bioavailability of hydrophobic organic compounds in sediment is the use of Tenax-extractable concentrations. A 6-h or 24-h single-point Tenax-extractable concentration correlates to both bioaccumulation and toxicity. This method has demonstrated effectiveness for several hydrophobic organic compounds in various organisms under both field and laboratory conditions. In addition, a Tenax bioaccumulation model was developed for multiple compounds relating 24-h Tenax-extractable concentrations to oligochaete tissue concentrations exposed in both the laboratory and field. This model has demonstrated predictive capacity for additional compounds and species. Use of Tenax-extractable concentrations to estimate exposure is rapid, simple, straightforward, and relatively inexpensive, as well as accurate. Therefore, this method would be an invaluable tool if implemented in risk assessments. © 2015 SETAC.

Gas uptake and chemical aging of semisolid organic aerosol particles

PubMed Central

Shiraiwa, Manabu; Ammann, Markus; Koop, Thomas; Pöschl, Ulrich

2011-01-01

Organic substances can adopt an amorphous solid or semisolid state, influencing the rate of heterogeneous reactions and multiphase processes in atmospheric aerosols. Here we demonstrate how molecular diffusion in the condensed phase affects the gas uptake and chemical transformation of semisolid organic particles. Flow tube experiments show that the ozone uptake and oxidative aging of amorphous protein is kinetically limited by bulk diffusion. The reactive gas uptake exhibits a pronounced increase with relative humidity, which can be explained by a decrease of viscosity and increase of diffusivity due to hygroscopic water uptake transforming the amorphous organic matrix from a glassy to a semisolid state (moisture-induced phase transition). The reaction rate depends on the condensed phase diffusion coefficients of both the oxidant and the organic reactant molecules, which can be described by a kinetic multilayer flux model but not by the traditional resistor model approach of multiphase chemistry. The chemical lifetime of reactive compounds in atmospheric particles can increase from seconds to days as the rate of diffusion in semisolid phases can decrease by multiple orders of magnitude in response to low temperature or low relative humidity. The findings demonstrate that the occurrence and properties of amorphous semisolid phases challenge traditional views and require advanced formalisms for the description of organic particle formation and transformation in atmospheric models of aerosol effects on air quality, public health, and climate. PMID:21690350

Studying the Accuracy of Software Process Elicitation: The User Articulated Model

ERIC Educational Resources Information Center

Crabtree, Carlton A.

2010-01-01

Process models are often the basis for demonstrating improvement and compliance in software engineering organizations. A descriptive model is a type of process model describing the human activities in software development that actually occur. The purpose of a descriptive model is to provide a documented baseline for further process improvement…

A novel microfluidic model can mimic organ-specific metastasis of circulating tumor cells.

PubMed

Kong, Jing; Luo, Yong; Jin, Dong; An, Fan; Zhang, Wenyuan; Liu, Lilu; Li, Jiao; Fang, Shimeng; Li, Xiaojie; Yang, Xuesong; Lin, Bingcheng; Liu, Tingjiao

2016-11-29

A biomimetic microsystem might compensate costly and time-consuming animal metastatic models. Herein we developed a biomimetic microfluidic model to study cancer metastasis. Primary cells isolated from different organs were cultured on the microlfuidic model to represent individual organs. Breast and salivary gland cancer cells were driven to flow over primary cell culture chambers, mimicking dynamic adhesion of circulating tumor cells (CTCs) to endothelium in vivo. These flowing artificial CTCs showed different metastatic potentials to lung on the microfluidic model. The traditional nude mouse model of lung metastasis was performed to investigate the physiological similarity of the microfluidic model to animal models. It was found that the metastatic potential of different cancer cells assessed by the microfluidic model was in agreement with that assessed by the nude mouse model. Furthermore, it was demonstrated that the metastatic inhibitor AMD3100 inhibited lung metastasis effectively in both the microfluidic model and the nude mouse model. Then the microfluidic model was used to mimick liver and bone metastasis of CTCs and confirm the potential for research of multiple-organ metastasis. Thus, the metastasis of CTCs to different organs was reconstituted on the microfluidic model. It may expand the capabilities of traditional cell culture models, providing a low-cost, time-saving, and rapid alternative to animal models.

Modeling the C. elegans nematode and its environment using a particle system.

PubMed

Rönkkö, Mauno; Wong, Garry

2008-07-21

A particle system, as understood in computer science, is a novel technique for modeling living organisms in their environment. Such particle systems have traditionally been used for modeling the complex dynamics of fluids and gases. In the present study, a particle system was devised to model the movement and feeding behavior of the nematode Caenorhabditis elegans in three different virtual environments: gel, liquid, and soil. The results demonstrate that distinct movements of the nematode can be attributed to its mechanical interactions with the virtual environment. These results also revealed emergent properties associated with modeling organisms within environment-based systems.

3D Printed Organ Models with Physical Properties of Tissue and Integrated Sensors.

PubMed

Qiu, Kaiyan; Zhao, Zichen; Haghiashtiani, Ghazaleh; Guo, Shuang-Zhuang; He, Mingyu; Su, Ruitao; Zhu, Zhijie; Bhuiyan, Didarul B; Murugan, Paari; Meng, Fanben; Park, Sung Hyun; Chu, Chih-Chang; Ogle, Brenda M; Saltzman, Daniel A; Konety, Badrinath R; Sweet, Robert M; McAlpine, Michael C

2018-03-01

The design and development of novel methodologies and customized materials to fabricate patient-specific 3D printed organ models with integrated sensing capabilities could yield advances in smart surgical aids for preoperative planning and rehearsal. Here, we demonstrate 3D printed prostate models with physical properties of tissue and integrated soft electronic sensors using custom-formulated polymeric inks. The models show high quantitative fidelity in static and dynamic mechanical properties, optical characteristics, and anatomical geometries to patient tissues and organs. The models offer tissue-mimicking tactile sensation and behavior and thus can be used for the prediction of organ physical behavior under deformation. The prediction results show good agreement with values obtained from simulations. The models also allow the application of surgical and diagnostic tools to their surface and inner channels. Finally, via the conformal integration of 3D printed soft electronic sensors, pressure applied to the models with surgical tools can be quantitatively measured.

3D Printed Organ Models with Physical Properties of Tissue and Integrated Sensors

PubMed Central

Qiu, Kaiyan; Zhao, Zichen; Haghiashtiani, Ghazaleh; Guo, Shuang-Zhuang; He, Mingyu; Su, Ruitao; Zhu, Zhijie; Bhuiyan, Didarul B.; Murugan, Paari; Meng, Fanben; Park, Sung Hyun; Chu, Chih-Chang; Ogle, Brenda M.; Saltzman, Daniel A.; Konety, Badrinath R.

2017-01-01

The design and development of novel methodologies and customized materials to fabricate patient-specific 3D printed organ models with integrated sensing capabilities could yield advances in smart surgical aids for preoperative planning and rehearsal. Here, we demonstrate 3D printed prostate models with physical properties of tissue and integrated soft electronic sensors using custom-formulated polymeric inks. The models show high quantitative fidelity in static and dynamic mechanical properties, optical characteristics, and anatomical geometries to patient tissues and organs. The models offer tissue-mimicking tactile sensation and behavior and thus can be used for the prediction of organ physical behavior under deformation. The prediction results show good agreement with values obtained from simulations. The models also allow the application of surgical and diagnostic tools to their surface and inner channels. Finally, via the conformal integration of 3D printed soft electronic sensors, pressure applied to the models with surgical tools can be quantitatively measured. PMID:29608202

A comparison of major petroleum life cycle models

EPA Science Inventory

Many organizations have attempted to develop an accurate well-to-pump life cycle model of petroleum products in order to inform decision makers of the consequences of its use. Our paper studies five of these models, demonstrating the differences in their predictions and attemptin...

The organizational structure of intensive care units and its influence on patient outcomes.

PubMed

Kutsogiannis, D J; Hague, C; Triska, O H; Johnston, R G; Noseworthy, T

2001-01-01

Despite the growing body of knowledge on the theory of organization, the application of such theory to the organization of intensive care units is in its infancy. Our knowledge about the influence of ICU organization on patient outcomes is limited. Development of instruments to measure ICU organization, and their implementation in studies of new therapies and technologies, will assist in demonstrating the effect of various models of ICU organization on the provision of clinical care.

The potential impact of accountable care organizations with respect to cost and quality with special attention to imaging.

PubMed

Mukherji, Suresh K

2014-04-01

An accountable care organization is a form of a managed care organization in which a group of networked health care providers, which may include hospitals, group practices, networks of practices, hospital-provider partnerships, or joint ventures, are accountable for the health care of a defined group of patients. Initial results of the institutions participating in CMS's Physician Group Demonstration Project did not demonstrate a substantial reduction in imaging that could be directly attributed to the accountable care organization model. However, the initial results suggest that incentive-based methodology appears to be successful for increasing compliance for measuring quality metrics. Copyright © 2014 American College of Radiology. Published by Elsevier Inc. All rights reserved.

COP-compost: a software to study the degradation of organic pollutants in composts.

PubMed

Zhang, Y; Lashermes, G; Houot, S; Zhu, Y-G; Barriuso, E; Garnier, P

2014-02-01

Composting has been demonstrated to be effective in degrading organic pollutants (OP) whose behaviour depends on the composting conditions, the microbial populations activated and interactions with organic matters. The fate of OP during composting involves complex mechanisms and models can be helpful tools for educational and scientific purposes, as well as for industrialists who want to optimise the composting process for OP elimination. A COP-Compost model, which couples an organic carbon (OC) module and an organic pollutant (OP) module and which simulates the changes of organic matter, organic pollutants and the microbial activities during the composting process, has been proposed and calibrated for a first set of OP in a previous study. The objectives of the present work were (1) to introduce the COP-Compost model from its convenient interface to a potential panel of users, (2) to show the variety of OP that could be simulated, including the possibility of choosing between degradation through co-metabolism or specific metabolism and (3) to show the effect of the initial characteristics of organic matter quality and its microbial biomass on the simulated results of the OP dynamic. In the model, we assumed that the pollutants can be adsorbed on organic matter according to the biochemical quality of the OC and that the microorganisms can degrade the pollutants at the same time as they degrade OC (by co-metabolism). A composting experiment describing two different (14)C-labelled organic pollutants, simazine and pyrene, were chosen from the literature because the four OP fractions simulated in the model were measured during the study (the mineralised, soluble, sorbed and non-extractable fractions). Except for the mineralised fraction of simazine, a good agreement was achieved between the simulated and experimental results describing the evolution of the different organic fractions. For simazine, a specific biomass had to be added. To assess the relative importance of organic matter dynamics on the organic pollutants' behaviour, a sensitivity analysis was conducted. The sensitivity analysis demonstrated that the parameters associated with organic matter dynamics and its initial microbial biomass greatly influenced the evolution of all the OP fractions, although the initial biochemical quality of the OC did not have a significant impact on the OP evolution.

A Framework for Linking Population Model Development with Ecological Risk Assessment Objectives.

EPA Science Inventory

The value of models that link organism‐level impacts to the responses of a population in ecological risk assessments (ERAs) has been demonstrated extensively over the past few decades. There is little debate about the utility of these models to translate multiple organism&#...

Springtails in the Classroom: Collembola as Model Organisms for Inquiry-based Laboratories.

ERIC Educational Resources Information Center

Moore, John C.; Tripp, Bradley B.; Simpson, Rod T.; Coleman, David C.

2000-01-01

Advocates the use of springtails (Collembola) in the K-12 classroom as a model invertebrate that can easily be reared and manipulated to demonstrate key concepts in biology. Describes experimental procedures using springtails. (SAH)

Inactive Publics: The Forgotten Publics in Public Relations.

ERIC Educational Resources Information Center

Hallahan, Kirk

2000-01-01

Notes that recent public relations theory has largely ignored inactive publics, stakeholder groups that demonstrate low levels of knowledge and involvement in the organization or its products, services, candidates, or causes, but are important to an organization. Examines the nature of inactive publics and proposes a model that locates inactive…

Neurocomputation by Reaction Diffusion

NASA Astrophysics Data System (ADS)

Liang, Ping

1995-08-01

This Letter demonstrates the possible role nonsynaptic diffusion neurotransmission may play in neurocomputation using an artificial neural network model. A reaction-diffusion neural network model with field-based information-processing mechanisms is proposed. The advantages of nonsynaptic field neurotransmission from a computational viewpoint demonstrated in this Letter include long-range inhibition using only local interaction, nonhardwired and changeable (target specific) long-range communication pathways, and multiple simultaneous spatiotemporal organization processes in the same medium.

Influence of variable selection on partial least squares discriminant analysis models for explosive residue classification

NASA Astrophysics Data System (ADS)

De Lucia, Frank C., Jr.; Gottfried, Jennifer L.

2011-02-01

Using a series of thirteen organic materials that includes novel high-nitrogen energetic materials, conventional organic military explosives, and benign organic materials, we have demonstrated the importance of variable selection for maximizing residue discrimination with partial least squares discriminant analysis (PLS-DA). We built several PLS-DA models using different variable sets based on laser induced breakdown spectroscopy (LIBS) spectra of the organic residues on an aluminum substrate under an argon atmosphere. The model classification results for each sample are presented and the influence of the variables on these results is discussed. We found that using the whole spectra as the data input for the PLS-DA model gave the best results. However, variables due to the surrounding atmosphere and the substrate contribute to discrimination when the whole spectra are used, indicating this may not be the most robust model. Further iterative testing with additional validation data sets is necessary to determine the most robust model.

Modeling the influence of organic acids on soil weathering

NASA Astrophysics Data System (ADS)

Lawrence, Corey; Harden, Jennifer; Maher, Kate

2014-08-01

Biological inputs and organic matter cycling have long been regarded as important factors in the physical and chemical development of soils. In particular, the extent to which low molecular weight organic acids, such as oxalate, influence geochemical reactions has been widely studied. Although the effects of organic acids are diverse, there is strong evidence that organic acids accelerate the dissolution of some minerals. However, the influence of organic acids at the field-scale and over the timescales of soil development has not been evaluated in detail. In this study, a reactive-transport model of soil chemical weathering and pedogenic development was used to quantify the extent to which organic acid cycling controls mineral dissolution rates and long-term patterns of chemical weathering. Specifically, oxalic acid was added to simulations of soil development to investigate a well-studied chronosequence of soils near Santa Cruz, CA. The model formulation includes organic acid input, transport, decomposition, organic-metal aqueous complexation and mineral surface complexation in various combinations. Results suggest that although organic acid reactions accelerate mineral dissolution rates near the soil surface, the net response is an overall decrease in chemical weathering. Model results demonstrate the importance of organic acid input concentrations, fluid flow, decomposition and secondary mineral precipitation rates on the evolution of mineral weathering fronts. In particular, model soil profile evolution is sensitive to kaolinite precipitation and oxalate decomposition rates. The soil profile-scale modeling presented here provides insights into the influence of organic carbon cycling on soil weathering and pedogenesis and supports the need for further field-scale measurements of the flux and speciation of reactive organic compounds.

Modeling the influence of organic acids on soil weathering

USGS Publications Warehouse

Lawrence, Corey R.; Harden, Jennifer W.; Maher, Kate

2014-01-01

Biological inputs and organic matter cycling have long been regarded as important factors in the physical and chemical development of soils. In particular, the extent to which low molecular weight organic acids, such as oxalate, influence geochemical reactions has been widely studied. Although the effects of organic acids are diverse, there is strong evidence that organic acids accelerate the dissolution of some minerals. However, the influence of organic acids at the field-scale and over the timescales of soil development has not been evaluated in detail. In this study, a reactive-transport model of soil chemical weathering and pedogenic development was used to quantify the extent to which organic acid cycling controls mineral dissolution rates and long-term patterns of chemical weathering. Specifically, oxalic acid was added to simulations of soil development to investigate a well-studied chronosequence of soils near Santa Cruz, CA. The model formulation includes organic acid input, transport, decomposition, organic-metal aqueous complexation and mineral surface complexation in various combinations. Results suggest that although organic acid reactions accelerate mineral dissolution rates near the soil surface, the net response is an overall decrease in chemical weathering. Model results demonstrate the importance of organic acid input concentrations, fluid flow, decomposition and secondary mineral precipitation rates on the evolution of mineral weathering fronts. In particular, model soil profile evolution is sensitive to kaolinite precipitation and oxalate decomposition rates. The soil profile-scale modeling presented here provides insights into the influence of organic carbon cycling on soil weathering and pedogenesis and supports the need for further field-scale measurements of the flux and speciation of reactive organic compounds.

A Fast Technology Infusion Model for Aerospace Organizations

NASA Technical Reports Server (NTRS)

Shapiro, Andrew A.; Schone, Harald; Brinza, David E.; Garrett, Henry B.; Feather, Martin S.

2006-01-01

A multi-year Fast Technology Infusion initiative proposes a model for aerospace organizations to improve the cost-effectiveness by which they mature new, in-house developed software and hardware technologies for space mission use. The first year task under the umbrella of this initiative will provide the framework to demonstrate and document the fast infusion process. The viability of this approach will be demonstrated on two technologies developed in prior years with internal Jet Propulsion Laboratory (JPL) funding. One hardware technology and one software technology were selected for maturation within one calendar year or less. The overall objective is to achieve cost and time savings in the qualification of technologies. At the end of the recommended three-year effort, we will have demonstrated for six or more in-house developed technologies a clear path to insertion using a documented process that permits adaptation to a broad range of hardware and software projects.

A new diagnostic for tropospheric ozone production

NASA Astrophysics Data System (ADS)

Edwards, Peter M.; Evans, Mathew J.

2017-11-01

Tropospheric ozone is important for the Earth's climate and air quality. It is produced during the oxidation of organics in the presence of nitrogen oxides. Due to the range of organic species emitted and the chain-like nature of their oxidation, this chemistry is complex and understanding the role of different processes (emission, deposition, chemistry) is difficult. We demonstrate a new methodology for diagnosing ozone production based on the processing of bonds contained within emitted molecules, the fate of which is determined by the conservation of spin of the bonding electrons. Using this methodology to diagnose ozone production in the GEOS-Chem chemical transport model, we demonstrate its advantages over the standard diagnostic. We show that the number of bonds emitted, their chemistry and lifetime, and feedbacks on OH are all important in determining the ozone production within the model and its sensitivity to changes. This insight may allow future model-model comparisons to better identify the root causes of model differences.

A predictive framework for evaluating models of semantic organization in free recall

PubMed Central

Morton, Neal W; Polyn, Sean M.

2016-01-01

Research in free recall has demonstrated that semantic associations reliably influence the organization of search through episodic memory. However, the specific structure of these associations and the mechanisms by which they influence memory search remain unclear. We introduce a likelihood-based model-comparison technique, which embeds a model of semantic structure within the context maintenance and retrieval (CMR) model of human memory search. Within this framework, model variants are evaluated in terms of their ability to predict the specific sequence in which items are recalled. We compare three models of semantic structure, latent semantic analysis (LSA), global vectors (GloVe), and word association spaces (WAS), and find that models using WAS have the greatest predictive power. Furthermore, we find evidence that semantic and temporal organization is driven by distinct item and context cues, rather than a single context cue. This finding provides important constraint for theories of memory search. PMID:28331243

Functional Coupling of Human Microphysiology Systems: Intestine, Liver, Kidney Proximal Tubule, Blood-Brain Barrier and Skeletal Muscle

PubMed Central

Vernetti, Lawrence; Gough, Albert; Baetz, Nicholas; Blutt, Sarah; Broughman, James R.; Brown, Jacquelyn A.; Foulke-Abel, Jennifer; Hasan, Nesrin; In, Julie; Kelly, Edward; Kovbasnjuk, Olga; Repper, Jonathan; Senutovitch, Nina; Stabb, Janet; Yeung, Catherine; Zachos, Nick C.; Donowitz, Mark; Estes, Mary; Himmelfarb, Jonathan; Truskey, George; Wikswo, John P.; Taylor, D. Lansing

2017-01-01

Organ interactions resulting from drug, metabolite or xenobiotic transport between organs are key components of human metabolism that impact therapeutic action and toxic side effects. Preclinical animal testing often fails to predict adverse outcomes arising from sequential, multi-organ metabolism of drugs and xenobiotics. Human microphysiological systems (MPS) can model these interactions and are predicted to dramatically improve the efficiency of the drug development process. In this study, five human MPS models were evaluated for functional coupling, defined as the determination of organ interactions via an in vivo-like sequential, organ-to-organ transfer of media. MPS models representing the major absorption, metabolism and clearance organs (the jejunum, liver and kidney) were evaluated, along with skeletal muscle and neurovascular models. Three compounds were evaluated for organ-specific processing: terfenadine for pharmacokinetics (PK) and toxicity; trimethylamine (TMA) as a potentially toxic microbiome metabolite; and vitamin D3. We show that the organ-specific processing of these compounds was consistent with clinical data, and discovered that trimethylamine-N-oxide (TMAO) crosses the blood-brain barrier. These studies demonstrate the potential of human MPS for multi-organ toxicity and absorption, distribution, metabolism and excretion (ADME), provide guidance for physically coupling MPS, and offer an approach to coupling MPS with distinct media and perfusion requirements. PMID:28176881

The Use of Mathematical Modelling for Improving the Tissue Engineering of Organs and Stem Cell Therapy.

PubMed

Lemon, Greg; Sjoqvist, Sebastian; Lim, Mei Ling; Feliu, Neus; Firsova, Alexandra B; Amin, Risul; Gustafsson, Ylva; Stuewer, Annika; Gubareva, Elena; Haag, Johannes; Jungebluth, Philipp; Macchiarini, Paolo

2016-01-01

Regenerative medicine is a multidisciplinary field where continued progress relies on the incorporation of a diverse set of technologies from a wide range of disciplines within medicine, science and engineering. This review describes how one such technique, mathematical modelling, can be utilised to improve the tissue engineering of organs and stem cell therapy. Several case studies, taken from research carried out by our group, ACTREM, demonstrate the utility of mechanistic mathematical models to help aid the design and optimisation of protocols in regenerative medicine.

Generation of Organ-conditioned Media and Applications for Studying Organ-specific Influences on Breast Cancer Metastatic Behavior.

PubMed

Piaseczny, Matthew M; Pio, Graciella M; Chu, Jenny E; Xia, Ying; Nguyen, Kim; Goodale, David; Allan, Alison

2016-06-13

Breast cancer preferentially metastasizes to the lymph node, bone, lung, brain and liver in breast cancer patients. Previous research efforts have focused on identifying factors inherent to breast cancer cells that are responsible for this observed metastatic pattern (termed organ tropism), however much less is known about factors present within specific organs that contribute to this process. This is in part because of a lack of in vitro model systems that accurately recapitulate the organ microenvironment. To address this, an ex vivo model system has been established that allows for the study of soluble factors present within different organ microenvironments. This model consists of generating conditioned media from organs (lymph node, bone, lung, and brain) isolated from normal athymic nude mice. The model system has been validated by demonstrating that different breast cancer cell lines display cell-line specific and organ-specific malignant behavior in response to organ-conditioned media that corresponds to their in vivo metastatic potential. This model system can be used to identify and evaluate specific organ-derived soluble factors that may play a role in the metastatic behavior of breast and other types of cancer cells, including influences on growth, migration, stem-like behavior, and gene expression, as well as the identification of potential new therapeutic targets for cancer. This is the first ex vivo model system that can be used to study organ-specific metastatic behavior in detail and evaluate the role of specific organ-derived soluble factors in driving the process of cancer metastasis.

Micro pore arrays in free standing cyclic olefin copolymer membranes: fabrication and surface functionalization strategies for in-vitro barrier tissue models

NASA Astrophysics Data System (ADS)

Gel, M.; Kandasamy, S.; Cartledge, K.; Be, C. L.; Haylock, D.

2013-12-01

In recent years there has been growing interest in micro engineered in-vitro models of tissues and organs. These models are designed to mimic the in-vivo like physiological conditions with a goal to study human physiology in an organ-specific context or to develop in-vitro disease models. One of the challenges in the development of these models is the formation of barrier tissues in which the permeability is controlled locally by the tissues cultured at the interface. In-vitro models of barrier tissues are typically created by generating a monolayer of cells grown on thin porous membranes. This paper reports a robust preparation method for free standing porous cyclic olefin copolymer (COC) membranes. We also demonstrate that gelatin coated membranes facilitate formation of highly confluent monolayer of HUVECs. Membranes with thickness in the range of 2-3 um incorporating micro pores with diameter approximately 20 um were fabricated and integrated with microfluidic channels. The performance of the device was demonstrated with a model system mimicking the endothelial barrier in bone marrow sinusoids.

Effect of Antifungal Treatment in a Diet-Based Murine Model of Disseminated Candidiasis Acquired via the Gastrointestinal Tract

PubMed Central

Najvar, Laura K.; Bocanegra, Rosie; Olivo, Marcos; Kirkpatrick, William R.; Wiederhold, Nathan P.; Patterson, Thomas F.

2016-01-01

Candida albicans, normally found as a commensal in the gut, is a major human fungal pathogen responsible for both mucosal and systemic infections in a wide variety of immunocompromised individuals, including cancer patients and organ transplant recipients. The gastrointestinal tract represents a major portal of entry for the establishment of disseminated candidiasis in many of these individuals. Here we report the development of a diet-based mouse model for disseminated candidiasis acquired via the gastrointestinal tract. Using this model, as well as an appropriate immunosuppression regimen, we demonstrate that dissemination of C. albicans from the gastrointestinal tract can result in mortality within 30 days postinfection. We also show a significant increase in fungal burden in systemic organs, but not gastrointestinal tract organs, upon immunosuppression. Importantly, we demonstrate that the administration of two widely used antifungals, fluconazole and caspofungin, either pre- or postimmunosuppression, significantly reduces fungal burdens. This model should prove to be of significant value for testing the ability of both established and experimental therapeutics to inhibit C. albicans dissemination from the gastrointestinal tract in an immunocompromised host as well as the subsequent mortality that can result from disseminated candidiasis. PMID:27572393

Self-Organized Cerebellar Tissue from Human Pluripotent Stem Cells and Disease Modeling with Patient-Derived iPSCs.

PubMed

Muguruma, Keiko

2018-02-01

Recent advances in the techniques that differentiate induced pluripotent stem cells (iPSCs) into specific types of cells enabled us to establish in vitro cell-based models as a platform for drug discovery. iPSC-derived disease models are advantageous to generation of a large number of cells required for high-throughput screening. Furthermore, disease-relevant cells differentiated from patient-derived iPSCs are expected to recapitulate the disorder-specific pathogenesis and physiology in vitro. Such disease-relevant cells will be useful for developing effective therapies. We demonstrated that cerebellar tissues are generated from human PSCs (hPSCs) in 3D culture systems that recapitulate the in vivo microenvironments associated with the isthmic organizer. Recently, we have succeeded in generation of spinocerebellar ataxia (SCA) patient-derived Purkinje cells by combining the iPSC technology and the self-organizing stem cell 3D culture technology. We demonstrated that SCA6-derived Purkinje cells exhibit vulnerability to triiodothyronine depletion, which is suppressed by treatment with thyrotropin-releasing hormone and Riluzole. We further discuss applications of patient-specific iPSCs to intractable cerebellar disease.

Organic condensation: a vital link connecting aerosol formation to cloud condensation nuclei (CCN) concentrations

NASA Astrophysics Data System (ADS)

Riipinen, I.; Pierce, J. R.; Yli-Juuti, T.; Nieminen, T.; Häkkinen, S.; Ehn, M.; Junninen, H.; Lehtipalo, K.; Petäjä, T.; Slowik, J.; Chang, R.; Shantz, N. C.; Abbatt, J.; Leaitch, W. R.; Kerminen, V.-M.; Worsnop, D. R.; Pandis, S. N.; Donahue, N. M.; Kulmala, M.

2011-04-01

Atmospheric aerosol particles influence global climate as well as impair air quality through their effects on atmospheric visibility and human health. Ultrafine (<100 nm) particles often dominate aerosol numbers, and nucleation of atmospheric vapors is an important source of these particles. To have climatic relevance, however, the freshly nucleated particles need to grow in size. We combine observations from two continental sites (Egbert, Canada and Hyytiälä, Finland) to show that condensation of organic vapors is a crucial factor governing the lifetimes and climatic importance of the smallest atmospheric particles. We model the observed ultrafine aerosol growth with a simplified scheme approximating the condensing species as a mixture of effectively non-volatile and semi-volatile species, demonstrate that state-of-the-art organic gas-particle partitioning models fail to reproduce the observations, and propose a modeling approach that is consistent with the measurements. We find that roughly half of the mass of the condensing mass needs to be distributed proportional to the aerosol surface area (thus implying that the condensation is governed by gas-phase concentration rather than the equilibrium vapour pressure) to explain the observed aerosol growth. We demonstrate the large sensitivity of predicted number concentrations of cloud condensation nuclei (CCN) to these interactions between organic vapors and the smallest atmospheric nanoparticles - highlighting the need for representing this process in global climate models.

Coordinating the Commons: Diversity & Dynamics in Open Collaborations

ERIC Educational Resources Information Center

Morgan, Jonathan T.

2013-01-01

The success of Wikipedia demonstrates that open collaboration can be an effective model for organizing geographically-distributed volunteers to perform complex, sustained work at a massive scale. However, Wikipedia's history also demonstrates some of the challenges that large, long-term open collaborations face: the core community of Wikipedia…

OCEANFILMS-2: Representing coadsorption of saccharides in marine films and potential impacts on modeled marine aerosol chemistry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burrows, Susannah M.; Gobrogge, Eric; Fu, Li

Here we show that the addition of chemical interactions of soluble polysaccharides with a surfactant monolayer improves agreement of modeled sea spray chemistry with observed marine aerosol chemistry. In particular, the fraction of hydroxyl functional groups in modeled sea spray organic matter is increased, improving agreement with FTIR observations of marine aerosol composition. The overall organic fraction of submicron sea spray also increases, allowing organic mass fractions in the range 0.5 – 0.7 for submicron sea spray particles over highly active phytoplankton blooms. We show results from Sum Frequency Generation (SFG) experiments that support the modeling approach, by demonstrating thatmore » soluble polysaccharides can strongly adsorb to a lipid monolayer via columbic interactions under appropriate conditions.« less

Mathematical model for the contribution of individual organs to non-zero y-intercepts in single and multi-compartment linear models of whole-body energy expenditure.

PubMed

Kaiyala, Karl J

2014-01-01

Mathematical models for the dependence of energy expenditure (EE) on body mass and composition are essential tools in metabolic phenotyping. EE scales over broad ranges of body mass as a non-linear allometric function. When considered within restricted ranges of body mass, however, allometric EE curves exhibit 'local linearity.' Indeed, modern EE analysis makes extensive use of linear models. Such models typically involve one or two body mass compartments (e.g., fat free mass and fat mass). Importantly, linear EE models typically involve a non-zero (usually positive) y-intercept term of uncertain origin, a recurring theme in discussions of EE analysis and a source of confounding in traditional ratio-based EE normalization. Emerging linear model approaches quantify whole-body resting EE (REE) in terms of individual organ masses (e.g., liver, kidneys, heart, brain). Proponents of individual organ REE modeling hypothesize that multi-organ linear models may eliminate non-zero y-intercepts. This could have advantages in adjusting REE for body mass and composition. Studies reveal that individual organ REE is an allometric function of total body mass. I exploit first-order Taylor linearization of individual organ REEs to model the manner in which individual organs contribute to whole-body REE and to the non-zero y-intercept in linear REE models. The model predicts that REE analysis at the individual organ-tissue level will not eliminate intercept terms. I demonstrate that the parameters of a linear EE equation can be transformed into the parameters of the underlying 'latent' allometric equation. This permits estimates of the allometric scaling of EE in a diverse variety of physiological states that are not represented in the allometric EE literature but are well represented by published linear EE analyses.

Transport of organic anions and cations in murine embryonic kidney development and in serially-reaggregated engineered kidneys

PubMed Central

Lawrence, Melanie L.; Chang, C-Hong; Davies, Jamie A.

2015-01-01

Recent advances in renal tissue engineering have shown that dissociated, early renogenic tissue from the developing embryo can self-assemble into morphologically accurate kidney-like organs arranged around a central collecting duct tree. In order for such self-assembled kidneys to be useful therapeutically or as models for drug screening, it is necessary to demonstrate that they are functional. One of the main functional characteristics of mature kidneys is transport of organic anions and cations into and out of the proximal tubule. Here, we show that the transport function of embryonic kidneys allowed to develop in culture follows a developmental time-course that is comparable to embryonic kidney development in vivo. We also demonstrate that serially-reaggregated engineered kidneys can transport organic anions and cations through specific uptake and efflux channels. These results support the physiological relevance of kidneys grown in culture, a commonly used model for kidney development and research, and suggest that serially-reaggregated kidneys self-assembled from separated cells have some functional characteristics of intact kidneys. PMID:25766625

Modeling Interval Temporal Dependencies for Complex Activities Understanding

DTIC Science & Technology

2013-10-11

ORGANIZATION NAMES AND ADDRESSES U.S. Army Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 15. SUBJECT TERMS Human activity modeling...computer vision applications: human activity recognition and facial activity recognition. The results demonstrate the superior performance of the

The MVP Model as an Organizing Framework for Neuroscience Findings Related to Learning

ERIC Educational Resources Information Center

Zakrajsek, Todd M.

2017-01-01

This chapter describes the ways in which the MVP model relates to recent research on neuroscience and learning, and demonstrates how those relationships may be used to better understand physiological impacts on motivation, and to facilitate improved learning.

Comparative Analyses of the β-Tubulin Gene and Molecular Modeling Reveal Molecular Insight into the Colchicine Resistance in Kinetoplastids Organisms

PubMed Central

Luis, Luis; Serrano, María Luisa; Hidalgo, Mariana; Mendoza-León, Alexis

2013-01-01

Differential susceptibility to microtubule agents has been demonstrated between mammalian cells and kinetoplastid organisms such as Leishmania spp. and Trypanosoma spp. The aims of this study were to identify and characterize the architecture of the putative colchicine binding site of Leishmania spp. and investigate the molecular basis of colchicine resistance. We cloned and sequenced the β-tubulin gene of Leishmania (Viannia) guyanensis and established the theoretical 3D model of the protein, using the crystallographic structure of the bovine protein as template. We identified mutations on the Leishmania   β-tubulin gene sequences on regions related to the putative colchicine-binding pocket, which generate amino acid substitutions and changes in the topology of this region, blocking the access of colchicine. The same mutations were found in the β-tubulin sequence of kinetoplastid organisms such as Trypanosoma cruzi, T. brucei, and T. evansi. Using molecular modelling approaches, we demonstrated that conformational changes include an elongation and torsion of an α-helix structure and displacement to the inside of the pocket of one β-sheet that hinders access of colchicine. We propose that kinetoplastid organisms show resistance to colchicine due to amino acids substitutions that generate structural changes in the putative colchicine-binding domain, which prevent colchicine access. PMID:24083244

Can Heterosexism Harm Organizations? Predicting the Perceived Organizational Citizenship Behaviors of Gay and Lesbian Employees

ERIC Educational Resources Information Center

Brenner, Bradley R.; Lyons, Heather Z.; Fassinger, Ruth E.

2010-01-01

An initial test and validation of a model predicting perceived organizational citizenship behaviors (OCBs) of lesbian and gay employees were conducted using structural equation modeling. The proposed structural model demonstrated acceptable goodness of ft and structural invariance across 2 samples (ns = 311 and 295), which suggested that…

Use of Molecular Models for Active Learning in Biochemistry Lecture Courses

ERIC Educational Resources Information Center

Hageman, James H.

2010-01-01

The pedagogical value of having biochemistry and organic chemistry students build and manipulate physical models of chemical species is well established in the literature. Nevertheless, for the most part, the use of molecular models is generally limited to several laboratory exercises or to demonstrations in the classroom setting. A simple…

University Library Strategy Development: A Conceptual Model of Researcher Performance to Inform Service Delivery

ERIC Educational Resources Information Center

Maddox, Alexia; Zhao, Linlin

2017-01-01

This case study presents a conceptual model of researcher performance developed by Deakin University Library, Australia. The model aims to organize research performance data into meaningful researcher profiles, referred to as researcher typologies, which support the demonstration of research impact and value. Three dimensions shaping researcher…

Financial and quality impacts of the Medicare physician group practice demonstration.

PubMed

Pope, Gregory; Kautter, John; Leung, Musetta; Trisolini, Michael; Adamache, Walter; Smith, Kevin

2014-01-01

To examine the impact of the Medicare Physician Group Practice (PGP) demonstration on expenditure, utilization, and quality outcomes. Secondary data analysis of 2001-2010 Medicare claims for 1,776,387 person years assigned to the ten participating provider organizations and 1,579,080 person years in the corresponding local comparison groups. We used a pre-post comparison group observational design consisting of four pre-demonstration years (1/01-12/04) and five demonstration years (4/05-3/10). We employed a propensity-weighted difference-in-differences regression model to estimate demonstration effects, adjusting for demographics, health status, geographic area, and secular trends. The ten demonstration sites combined saved $171 (2.0%) per assigned beneficiary person year (p<0.001) during the five-year demonstration period. Medicare paid performance bonuses to the participating PGPs that averaged $102 per person year. The net savings to the Medicare program were $69 (0.8%) per person year. Demonstration savings were achieved primarily from the inpatient setting. The demonstration improved quality of care as measured by six of seven claims-based process quality indicators. The PGP demonstration, which used a payment model similar to the Medicare Accountable Care Organization (ACO) program, resulted in small reductions in Medicare expenditures and inpatient utilization, and improvements in process quality indicators. Judging from this demonstration experience, it is unlikely that Medicare ACOs will initially achieve large savings. Nevertheless, ACOs paid through shared savings may be an important first step toward greater efficiency and quality in the Medicare fee-for-service program.

ForCent model development and testing using the Enriched Background Isotope Study experiment

Treesearch

William J. Parton; Paul J. Hanson; Chris Swanston; Margaret Torn; Susan E. Trumbore; William Riley; Robin Kelly

2010-01-01

The ForCent forest ecosystem model was developed by making major revisions to the DayCent model including: (1) adding a humus organic pool, (2) incorporating a detailed root growth model, and (3) including plant phenological growth patterns. Observed plant production and soil respiration data from 1993 to 2000 were used to demonstrate that the ForCent model could...

Predictive and mechanistic multivariate linear regression models for reaction development

PubMed Central

Santiago, Celine B.; Guo, Jing-Yao

2018-01-01

Multivariate Linear Regression (MLR) models utilizing computationally-derived and empirically-derived physical organic molecular descriptors are described in this review. Several reports demonstrating the effectiveness of this methodological approach towards reaction optimization and mechanistic interrogation are discussed. A detailed protocol to access quantitative and predictive MLR models is provided as a guide for model development and parameter analysis. PMID:29719711

A Modular Simulation Framework for Assessing Swarm Search Models

DTIC Science & Technology

2014-09-01

SUBTITLE A MODULAR SIMULATION FRAMEWORK FOR ASSESSING SWARM SEARCH MODELS 5. FUNDING NUMBERS 6. AUTHOR(S) Blake M. Wanier 7. PERFORMING ORGANIZATION...Numerical studies demonstrate the ability to leverage the developed simulation and analysis framework to investigate three canonical swarm search models ...as benchmarks for future exploration of more sophisticated swarm search scenarios. 14. SUBJECT TERMS Swarm Search, Search Theory, Modeling Framework

A thermodynamical model for stress-fiber organization in contractile cells.

PubMed

Foucard, Louis; Vernerey, Franck J

2012-01-02

Cell mechanical adaptivity to external stimuli is vital to many of its biological functions. A critical question is therefore to understand the formation and organization of the stress fibers from which emerge the cell's mechanical properties. By accounting for the mechanical aspects and the viscoelastic behavior of stress fibers, we here propose a thermodynamic model to predict the formation and orientation of stress fibers in contractile cells subjected to constant or cyclic stretch and different substrate stiffness. Our results demonstrate that the stress fibers viscoelastic behavior plays a crucial role in their formation and organization and shows good consistency with various experiments.

A mathematical model for adaptive transport network in path finding by true slime mold.

PubMed

Tero, Atsushi; Kobayashi, Ryo; Nakagaki, Toshiyuki

2007-02-21

We describe here a mathematical model of the adaptive dynamics of a transport network of the true slime mold Physarum polycephalum, an amoeboid organism that exhibits path-finding behavior in a maze. This organism possesses a network of tubular elements, by means of which nutrients and signals circulate through the plasmodium. When the organism is put in a maze, the network changes its shape to connect two exits by the shortest path. This process of path-finding is attributed to an underlying physiological mechanism: a tube thickens as the flux through it increases. The experimental evidence for this is, however, only qualitative. We constructed a mathematical model of the general form of the tube dynamics. Our model contains a key parameter corresponding to the extent of the feedback regulation between the thickness of a tube and the flux through it. We demonstrate the dependence of the behavior of the model on this parameter.

[Safety culture: definition, models and design].

PubMed

Pfaff, Holger; Hammer, Antje; Ernstmann, Nicole; Kowalski, Christoph; Ommen, Oliver

2009-01-01

Safety culture is a multi-dimensional phenomenon. Safety culture of a healthcare organization is high if it has a common stock in knowledge, values and symbols in regard to patients' safety. The article intends to define safety culture in the first step and, in the second step, demonstrate the effects of safety culture. We present the model of safety behaviour and show how safety culture can affect behaviour and produce safe behaviour. In the third step we will look at the causes of safety culture and present the safety-culture-model. The main hypothesis of this model is that the safety culture of a healthcare organization strongly depends on its communication culture and its social capital. Finally, we will investigate how the safety culture of a healthcare organization can be improved. Based on the safety culture model six measures to improve safety culture will be presented.

Functional recognition imaging using artificial neural networks: applications to rapid cellular identification via broadband electromechanical response

NASA Astrophysics Data System (ADS)

Nikiforov, M. P.; Reukov, V. V.; Thompson, G. L.; Vertegel, A. A.; Guo, S.; Kalinin, S. V.; Jesse, S.

2009-10-01

Functional recognition imaging in scanning probe microscopy (SPM) using artificial neural network identification is demonstrated. This approach utilizes statistical analysis of complex SPM responses at a single spatial location to identify the target behavior, which is reminiscent of associative thinking in the human brain, obviating the need for analytical models. We demonstrate, as an example of recognition imaging, rapid identification of cellular organisms using the difference in electromechanical activity over a broad frequency range. Single-pixel identification of model Micrococcus lysodeikticus and Pseudomonas fluorescens bacteria is achieved, demonstrating the viability of the method.

XFEM-based modeling of successive resections for preoperative image updating

NASA Astrophysics Data System (ADS)

Vigneron, Lara M.; Robe, Pierre A.; Warfield, Simon K.; Verly, Jacques G.

2006-03-01

We present a new method for modeling organ deformations due to successive resections. We use a biomechanical model of the organ, compute its volume-displacement solution based on the eXtended Finite Element Method (XFEM). The key feature of XFEM is that material discontinuities induced by every new resection can be handled without remeshing or mesh adaptation, as would be required by the conventional Finite Element Method (FEM). We focus on the application of preoperative image updating for image-guided surgery. Proof-of-concept demonstrations are shown for synthetic and real data in the context of neurosurgery.

Structural salience and the nonaccidentality of a Gestalt.

PubMed

Strother, Lars; Kubovy, Michael

2012-08-01

We perceive structure through a process of perceptual organization. Here we report a new perceptual organization phenomenon-the facilitation of visual grouping by global curvature. Observers viewed patterns that they perceived as organized into collections of curves. The patterns were perceptually ambiguous such that the perceived orientation of the patterns varied from trial to trial. When patterns were sufficiently dense and proximity was equated for the predominant perceptual alternatives, observers tended to perceive the organization with the greatest curvature. This effect is tantamount to visual grouping by maximal curvature and thus demonstrates an unprecedented effect of global structure on perceptual organization. We account for this result with a model that predicts the perceived organization of a pattern as function of its nonaccidentality, which we define as the probability that it could have occurred by chance. Our findings demonstrate a novel relationship between the geometry of a pattern and the visual salience of global structure. (c) 2012 APA, all rights reserved.

Money Management for Women: A Demonstration of the Role of Community Organizations in the Delivery of Consumer Education.

ERIC Educational Resources Information Center

Heller, Barbara R.; Florio, Carol

The Money Management for Women program was designed and implemented to provide lower-income women with financial planning information geared to their current level of understanding and financial circumstances. Objectives were to develop a model consumer education program and test the efficacy of community-based organizations as agents in…

Recapitulating cortical development with organoid culture in vitro and modeling abnormal spindle-like (ASPM related primary) microcephaly disease.

PubMed

Li, Rui; Sun, Le; Fang, Ai; Li, Peng; Wu, Qian; Wang, Xiaoqun

2017-11-01

The development of a cerebral organoid culture in vitro offers an opportunity to generate human brain-like organs to investigate mechanisms of human disease that are specific to the neurogenesis of radial glial (RG) and outer radial glial (oRG) cells in the ventricular zone (VZ) and subventricular zone (SVZ) of the developing neocortex. Modeling neuronal progenitors and the organization that produces mature subcortical neuron subtypes during early stages of development is essential for studying human brain developmental diseases. Several previous efforts have shown to grow neural organoid in culture dishes successfully, however we demonstrate a new paradigm that recapitulates neocortical development process with VZ, OSVZ formation and the lamination organization of cortical layer structure. In addition, using patient-specific induced pluripotent stem cells (iPSCs) with dysfunction of the Aspm gene from a primary microcephaly patient, we demonstrate neurogenesis defects result in defective neuronal activity in patient organoids, suggesting a new strategy to study human developmental diseases in central nerve system.

The phenomena of Pine's "four psychologies": their contrast and interplay as exhibited in the Beatles' "white album".

PubMed

Brog, M A

1995-01-01

Psychoanalytically informed clinicians are frequently challenged with recognizing and integrating into their work the diverse phenomena central to differing psychoanalytic theoretical frameworks. In addressing this dilemma, Pine has formulated a "multiple model" that recognizes the qualitatively different psychological phenomena and the distinct motivational forces emphasized by what he calls "the four psychologies of psychoanalysis," the psychologies of drive, ego, object relations and self. This model makes it possible to describe individual personality organizations in terms of psychological hierarchies of the phenomena of the four psychologies. Use of this model promotes a particular kind of listening stance that facilitates recognition and use of a wide variety of clinical data. The usefulness of this model is demonstrated through its application to a creative work, the Beatles' "White Album." This application shows the utility of Pine's psychological hierarchies in describing differing personality organizations, the "multiple functions" mental events can represent through serving the motives of multiple psychologies, and the frequent interactions that occur between the differing psychological phenomena. Pine's model facilitates a recognition that an important quality found in works by the Beatles is their demonstration in strikingly clear form, of the qualitatively different aspects of human experience emphasized by the four psychologies. The accessibility of Beatles music makes it a potentially valuable teaching tool for demonstrating Pine's model.

Energy-level alignment at organic heterointerfaces

PubMed Central

Oehzelt, Martin; Akaike, Kouki; Koch, Norbert; Heimel, Georg

2015-01-01

Today’s champion organic (opto-)electronic devices comprise an ever-increasing number of different organic-semiconductor layers. The functionality of these complex heterostructures largely derives from the relative alignment of the frontier molecular-orbital energies in each layer with respect to those in all others. Despite the technological relevance of the energy-level alignment at organic heterointerfaces, and despite continued scientific interest, a reliable model that can quantitatively predict the full range of phenomena observed at such interfaces is notably absent. We identify the limitations of previous attempts to formulate such a model and highlight inconsistencies in the interpretation of the experimental data they were based on. We then develop a theoretical framework, which we demonstrate to accurately reproduce experiment. Applying this theory, a comprehensive overview of all possible energy-level alignment scenarios that can be encountered at organic heterojunctions is finally given. These results will help focus future efforts on developing functional organic interfaces for superior device performance. PMID:26702447

Developing a molecular picture of soil organic matter–mineral interactions by quantifying organo–mineral binding

DOE PAGES

Newcomb, C. J.; Qafoku, N. P.; Grate, J. W.; ...

2017-08-30

Long residence times of soil organic matter have been attributed to reactive mineral surface sites that sorb organic species and cause inaccessibility due to isolation and chemical stabilization at the organic-mineral interface. Instrumentation for probing this interface is limited. As a result, much of the micron- and molecular-scale knowledge about organic-mineral interactions remains largely qualitative. We report the use of force spectroscopy to directly measure the binding between organic ligands with known chemical functionalities to soil minerals in aqueous environments. By systematically studying the role of organic functional group chemistry with model minerals, we demonstrate that the chemistry of bothmore » the organic ligand and mineral contribute to values of binding free energy and that changes in pH and ionic strength produce significant differences in binding energies. These direct measurements of molecular binding provide mechanistic insights into organo-mineral interactions, which could potentially inform land-carbon models that explicitly include mineral-bound C pools.« less

Developing a molecular picture of soil organic matter–mineral interactions by quantifying organo–mineral binding

DOE Office of Scientific and Technical Information (OSTI.GOV)

Newcomb, C. J.; Qafoku, N. P.; Grate, J. W.

Long residence times of soil organic matter have been attributed to reactive mineral surface sites that sorb organic species and cause inaccessibility due to isolation and chemical stabilization at the organic-mineral interface. Instrumentation for probing this interface is limited. As a result, much of the micron- and molecular-scale knowledge about organic-mineral interactions remains largely qualitative. We report the use of force spectroscopy to directly measure the binding between organic ligands with known chemical functionalities to soil minerals in aqueous environments. By systematically studying the role of organic functional group chemistry with model minerals, we demonstrate that the chemistry of bothmore » the organic ligand and mineral contribute to values of binding free energy and that changes in pH and ionic strength produce significant differences in binding energies. These direct measurements of molecular binding provide mechanistic insights into organo-mineral interactions, which could potentially inform land-carbon models that explicitly include mineral-bound C pools.« less

Reported emissions of organic gases are not consistent with observations

PubMed Central

Henry, Ronald C.; Spiegelman, Clifford H.; Collins, John F.; Park, EunSug

1997-01-01

Regulatory agencies and photochemical models of ozone rely on self-reported industrial emission rates of organic gases. Incorrect self-reported emissions can severely impact on air quality models and regulatory decisions. We compared self-reported emissions of organic gases in Houston, Texas, to measurements at a receptor site near the Houston ship channel, a major petrochemical complex. We analyzed hourly observations of total nonmethane organic carbon and 54 hydrocarbon compounds from C-2 to C-9 for the period June through November, 1993. We were able to demonstrate severe inconsistencies between reported emissions and major sources as derived from the data using a multivariate receptor model. The composition and the location of the sources as deduced from the data are not consistent with the reported industrial emissions. On the other hand, our observationally based methods did correctly identify the location and composition of a relatively small nearby chemical plant. This paper provides strong empirical evidence that regulatory agencies and photochemical models are making predictions based on inaccurate industrial emissions. PMID:11038551

Effect of Antifungal Treatment in a Diet-Based Murine Model of Disseminated Candidiasis Acquired via the Gastrointestinal Tract.

PubMed

Kadosh, David; Najvar, Laura K; Bocanegra, Rosie; Olivo, Marcos; Kirkpatrick, William R; Wiederhold, Nathan P; Patterson, Thomas F

2016-11-01

Candida albicans, normally found as a commensal in the gut, is a major human fungal pathogen responsible for both mucosal and systemic infections in a wide variety of immunocompromised individuals, including cancer patients and organ transplant recipients. The gastrointestinal tract represents a major portal of entry for the establishment of disseminated candidiasis in many of these individuals. Here we report the development of a diet-based mouse model for disseminated candidiasis acquired via the gastrointestinal tract. Using this model, as well as an appropriate immunosuppression regimen, we demonstrate that dissemination of C. albicans from the gastrointestinal tract can result in mortality within 30 days postinfection. We also show a significant increase in fungal burden in systemic organs, but not gastrointestinal tract organs, upon immunosuppression. Importantly, we demonstrate that the administration of two widely used antifungals, fluconazole and caspofungin, either pre- or postimmunosuppression, significantly reduces fungal burdens. This model should prove to be of significant value for testing the ability of both established and experimental therapeutics to inhibit C. albicans dissemination from the gastrointestinal tract in an immunocompromised host as well as the subsequent mortality that can result from disseminated candidiasis. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Emergence of a snake-like structure in mobile distributed agents: an exploratory agent-based modeling approach.

PubMed

Niazi, Muaz A

2014-01-01

The body structure of snakes is composed of numerous natural components thereby making it resilient, flexible, adaptive, and dynamic. In contrast, current computer animations as well as physical implementations of snake-like autonomous structures are typically designed to use either a single or a relatively smaller number of components. As a result, not only these artificial structures are constrained by the dimensions of the constituent components but often also require relatively more computationally intensive algorithms to model and animate. Still, these animations often lack life-like resilience and adaptation. This paper presents a solution to the problem of modeling snake-like structures by proposing an agent-based, self-organizing algorithm resulting in an emergent and surprisingly resilient dynamic structure involving a minimal of interagent communication. Extensive simulation experiments demonstrate the effectiveness as well as resilience of the proposed approach. The ideas originating from the proposed algorithm can not only be used for developing self-organizing animations but can also have practical applications such as in the form of complex, autonomous, evolvable robots with self-organizing, mobile components with minimal individual computational capabilities. The work also demonstrates the utility of exploratory agent-based modeling (EABM) in the engineering of artificial life-like complex adaptive systems.

Emergence of a Snake-Like Structure in Mobile Distributed Agents: An Exploratory Agent-Based Modeling Approach

PubMed Central

Niazi, Muaz A.

2014-01-01

The body structure of snakes is composed of numerous natural components thereby making it resilient, flexible, adaptive, and dynamic. In contrast, current computer animations as well as physical implementations of snake-like autonomous structures are typically designed to use either a single or a relatively smaller number of components. As a result, not only these artificial structures are constrained by the dimensions of the constituent components but often also require relatively more computationally intensive algorithms to model and animate. Still, these animations often lack life-like resilience and adaptation. This paper presents a solution to the problem of modeling snake-like structures by proposing an agent-based, self-organizing algorithm resulting in an emergent and surprisingly resilient dynamic structure involving a minimal of interagent communication. Extensive simulation experiments demonstrate the effectiveness as well as resilience of the proposed approach. The ideas originating from the proposed algorithm can not only be used for developing self-organizing animations but can also have practical applications such as in the form of complex, autonomous, evolvable robots with self-organizing, mobile components with minimal individual computational capabilities. The work also demonstrates the utility of exploratory agent-based modeling (EABM) in the engineering of artificial life-like complex adaptive systems. PMID:24701135

Coupled stochastic spatial and non-spatial simulations of ErbB1 signaling pathways demonstrate the importance of spatial organization in signal transduction.

PubMed

Costa, Michelle N; Radhakrishnan, Krishnan; Wilson, Bridget S; Vlachos, Dionisios G; Edwards, Jeremy S

2009-07-23

The ErbB family of receptors activates intracellular signaling pathways that control cellular proliferation, growth, differentiation and apoptosis. Given these central roles, it is not surprising that overexpression of the ErbB receptors is often associated with carcinogenesis. Therefore, extensive laboratory studies have been devoted to understanding the signaling events associated with ErbB activation. Systems biology has contributed significantly to our current understanding of ErbB signaling networks. However, although computational models have grown in complexity over the years, little work has been done to consider the spatial-temporal dynamics of receptor interactions and to evaluate how spatial organization of membrane receptors influences signaling transduction. Herein, we explore the impact of spatial organization of the epidermal growth factor receptor (ErbB1/EGFR) on the initiation of downstream signaling. We describe the development of an algorithm that couples a spatial stochastic model of membrane receptors with a nonspatial stochastic model of the reactions and interactions in the cytosol. This novel algorithm provides a computationally efficient method to evaluate the effects of spatial heterogeneity on the coupling of receptors to cytosolic signaling partners. Mathematical models of signal transduction rarely consider the contributions of spatial organization due to high computational costs. A hybrid stochastic approach simplifies analyses of the spatio-temporal aspects of cell signaling and, as an example, demonstrates that receptor clustering contributes significantly to the efficiency of signal propagation from ligand-engaged growth factor receptors.

Tax policy as a lifeline: encouraging blood and organ donation through tax credits.

PubMed

Clamon, Joseph B

2008-01-01

This article, the second concerning the organ donation crisis, proposes the use of tax policy to encourage blood and organ donation. After critiquing the ethical and logistical problems posed by other commercial and non-commercial solutions, the author demonstrates how tax credits can be used as an effective and ethical solution to address the shortage of donors. The author also offers two model statutes that provide guidance as to how a nonrefundable tax credit for blood and organ donation might operate in the tax code.

Factorial Based Response Surface Modeling with Confidence Intervals for Optimizing Thermal Optical Transmission Analysis of Atmospheric Black Carbon

EPA Science Inventory

We demonstrate how thermal-optical transmission analysis (TOT) for refractory light-absorbing carbon in atmospheric particulate matter was optimized with empirical response surface modeling. TOT employs pyrolysis to distinguish the mass of black carbon (BC) from organic carbon (...

DEMONSTRATION BULLETIN: X*TRAX MODEL 200 THERMAL DESORPTION SYSTEMS - CHEMICAL WASTE MANAGEMENT, INC.

EPA Science Inventory

The X*TRAX™ Mode! 200 Thermal Desorption System developed by Chemical Waste Management, Inc. (CWM), is a low-temperature process designed to separate organic contaminants from soils, sludges, and other solid media. The X*TRAX™ Model 200 is fully transportable and consists of thre...

BEN:LINCS: A Community Model for the Pennsylvania Education Network.

ERIC Educational Resources Information Center

Garrigan, Scott

BEN:LINCS (Bethlehem Education Network: A Local Instructional Network for Culture and Science), a Pennsylvania Testbed Project, attempts to demonstrate a sustainable model that supports network-based educational activities among schools, homes, libraries, museums, and local cultural organizations. The BEN:LINCS project envisioned a community-based…

Hybrid Modeling of Cell Signaling and Transcriptional Reprogramming and Its Application in C. elegans Development.

PubMed

Fertig, Elana J; Danilova, Ludmila V; Favorov, Alexander V; Ochs, Michael F

2011-01-01

Modeling of signal driven transcriptional reprogramming is critical for understanding of organism development, human disease, and cell biology. Many current modeling techniques discount key features of the biological sub-systems when modeling multiscale, organism-level processes. We present a mechanistic hybrid model, GESSA, which integrates a novel pooled probabilistic Boolean network model of cell signaling and a stochastic simulation of transcription and translation responding to a diffusion model of extracellular signals. We apply the model to simulate the well studied cell fate decision process of the vulval precursor cells (VPCs) in C. elegans, using experimentally derived rate constants wherever possible and shared parameters to avoid overfitting. We demonstrate that GESSA recovers (1) the effects of varying scaffold protein concentration on signal strength, (2) amplification of signals in expression, (3) the relative external ligand concentration in a known geometry, and (4) feedback in biochemical networks. We demonstrate that setting model parameters based on wild-type and LIN-12 loss-of-function mutants in C. elegans leads to correct prediction of a wide variety of mutants including partial penetrance of phenotypes. Moreover, the model is relatively insensitive to parameters, retaining the wild-type phenotype for a wide range of cell signaling rate parameters.

An efficient and robust MRI-guided radiotherapy planning approach for targeting abdominal organs and tumours in the mouse

PubMed Central

Bird, Luke; Tullis, Iain D. C.; Newman, Robert G.; Corroyer-Dulmont, Aurelien; Falzone, Nadia; Azad, Abul; Vallis, Katherine A.; Sansom, Owen J.; Muschel, Ruth J.; Vojnovic, Borivoj; Hill, Mark A.; Fokas, Emmanouil; Smart, Sean C.

2017-01-01

Introduction Preclinical CT-guided radiotherapy platforms are increasingly used but the CT images are characterized by poor soft tissue contrast. The aim of this study was to develop a robust and accurate method of MRI-guided radiotherapy (MR-IGRT) delivery to abdominal targets in the mouse. Methods A multimodality cradle was developed for providing subject immobilisation and its performance was evaluated. Whilst CT was still used for dose calculations, target identification was based on MRI. Each step of the radiotherapy planning procedure was validated initially in vitro using BANG gel dosimeters. Subsequently, MR-IGRT of normal adrenal glands with a size-matched collimated beam was performed. Additionally, the SK-N-SH neuroblastoma xenograft model and the transgenic KPC model of pancreatic ductal adenocarcinoma were used to demonstrate the applicability of our methods for the accurate delivery of radiation to CT-invisible abdominal tumours. Results The BANG gel phantoms demonstrated a targeting efficiency error of 0.56 ± 0.18 mm. The in vivo stability tests of body motion during MR-IGRT and the associated cradle transfer showed that the residual body movements are within this MR-IGRT targeting error. Accurate MR-IGRT of the normal adrenal glands with a size-matched collimated beam was confirmed by γH2AX staining. Regression in tumour volume was observed almost immediately post MR-IGRT in the neuroblastoma model, further demonstrating accuracy of x-ray delivery. Finally, MR-IGRT in the KPC model facilitated precise contouring and comparison of different treatment plans and radiotherapy dose distributions not only to the intra-abdominal tumour but also to the organs at risk. Conclusion This is, to our knowledge, the first study to demonstrate preclinical MR-IGRT in intra-abdominal organs. The proposed MR-IGRT method presents a state-of-the-art solution to enabling robust, accurate and efficient targeting of extracranial organs in the mouse and can operate with a sufficiently high throughput to allow fractionated treatments to be given. PMID:28453537

Trade Agreements: Impact on the U.S. Economy

DTIC Science & Technology

2010-03-11

the models have been criticized for lacking a strong theoretical basis, recent work has demonstrated that the model is consistent with the Ricardian ...structure and organization, production technology, investment, and capital flows in the form of foreign direct investment. General equilibrium models ...given sector or industry and assess the impact of the change on employment, production , and economic welfare. The Michigan Model and Estimates One

Factors associated with involvement in nonmetropolitan LGBTQ organizations: Proximity? Generativity? Minority stress? Social location?

PubMed

Paceley, Megan S; Oswald, Ramona Faith; Hardesty, Jennifer L

2014-01-01

Little is known about involvement in LGBTQ organizations. Factors associated with involvement in nonmetropolitan LGBTQ organizations were examined using logistic regression and survey data from 426 LGBTQ individuals residing in a nonmetropolitan region. Involvement was examined in five types of organizations (professional, social/recreational, religious, political, and community center/charity). The same model testing proximity, generativity, minority stress, and social location hypotheses was repeated for each organization type. Results demonstrate that the generativity hypothesis is most strongly supported. Indeed, emotional attachment to the LGBTQ community significantly increased the odds of involvement in every type of organization. However, the factors associated with involvement otherwise differed by organization type. Implications for organizational leaders are discussed.

Community Crowd-Funded Solar Finance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jagerson, Gordon "Ty"

The award supported the demonstration and development of the Village Power Platform, which enables community organizations to more readily develop, finance and operate solar installations on local community organizations. The platform enables partial or complete local ownership of the solar installation. The award specifically supported key features including financial modeling tools, community communications tools, crowdfunding mechanisms, a mobile app, and other critical features.

Computer-Assisted Instruction in the Basic Public Speaking Course: Issues of Development and Implementation.

ERIC Educational Resources Information Center

Vest, David; Tajchman, Ron

A study explained the manner in which a computer-assisted tutorial was built and assessed the utility of the courseware. The tutorial was designed to demonstrate the efficacy of good organization in informing the audience about a topic and provide appropriate models for the presentation of the well-organized informative speech. The topic of the…

The Human Performance Technology Model as a Framework for Implementation of Social Media in Hospitals

ERIC Educational Resources Information Center

Szyszlo, Ann M.

2014-01-01

Social media are ubiquitous and used by millions of people every day. Existing research on social media is primarily descriptive, survey based, and focused on who is using social media and how people and organizations are using the tools. Although many organizations have shown interest in using social media, they often demonstrate uncertainty…

Modeling the Free Carrier Recombination Kinetics in PTB7:PCBM Organic Photovoltaics

DOE PAGES

Oosterhout, Stefan D.; Ferguson, Andrew J.; Larson, Bryon W.; ...

2016-10-03

Currently the exact recombination mechanism of free carriers in organic photovoltaic (OPV) devices is poorly understood. Often a reduced Langevin model is used to describe the decay behavior of electrons and holes. Here we propose a novel, simple kinetic model that accurately describes the decay behavior of free carriers in the PTB7:PCBM organic photovoltaic blend. In order to accurately describe the recombination behavior of free carriers as measured by time-resolved microwave conductivity (TRMC), this model needs to only take into account free and trapped holes in the polymer, and free electrons in the fullerene. The model is consistent for differentmore » PTB7:PCBM blend ratios and spans a light intensity range of over 3 orders of magnitude. Furthermore, the model demonstrates that dark carriers exist in the polymer and interact with photoinduced charge carriers, and that the trapping and detrapping rates of the holes are of high importance to the overall carrier lifetime.« less

Mathematical Model for the Contribution of Individual Organs to Non-Zero Y-Intercepts in Single and Multi-Compartment Linear Models of Whole-Body Energy Expenditure

PubMed Central

Kaiyala, Karl J.

2014-01-01

Mathematical models for the dependence of energy expenditure (EE) on body mass and composition are essential tools in metabolic phenotyping. EE scales over broad ranges of body mass as a non-linear allometric function. When considered within restricted ranges of body mass, however, allometric EE curves exhibit ‘local linearity.’ Indeed, modern EE analysis makes extensive use of linear models. Such models typically involve one or two body mass compartments (e.g., fat free mass and fat mass). Importantly, linear EE models typically involve a non-zero (usually positive) y-intercept term of uncertain origin, a recurring theme in discussions of EE analysis and a source of confounding in traditional ratio-based EE normalization. Emerging linear model approaches quantify whole-body resting EE (REE) in terms of individual organ masses (e.g., liver, kidneys, heart, brain). Proponents of individual organ REE modeling hypothesize that multi-organ linear models may eliminate non-zero y-intercepts. This could have advantages in adjusting REE for body mass and composition. Studies reveal that individual organ REE is an allometric function of total body mass. I exploit first-order Taylor linearization of individual organ REEs to model the manner in which individual organs contribute to whole-body REE and to the non-zero y-intercept in linear REE models. The model predicts that REE analysis at the individual organ-tissue level will not eliminate intercept terms. I demonstrate that the parameters of a linear EE equation can be transformed into the parameters of the underlying ‘latent’ allometric equation. This permits estimates of the allometric scaling of EE in a diverse variety of physiological states that are not represented in the allometric EE literature but are well represented by published linear EE analyses. PMID:25068692

Implementing an error disclosure coaching model: A multicenter case study.

PubMed

White, Andrew A; Brock, Douglas M; McCotter, Patricia I; Shannon, Sarah E; Gallagher, Thomas H

2017-01-01

National guidelines call for health care organizations to provide around-the-clock coaching for medical error disclosure. However, frontline clinicians may not always seek risk managers for coaching. As part of a demonstration project designed to improve patient safety and reduce malpractice liability, we trained multidisciplinary disclosure coaches at 8 health care organizations in Washington State. The training was highly rated by participants, although not all emerged confident in their coaching skill. This multisite intervention can serve as a model for other organizations looking to enhance existing disclosure capabilities. Success likely requires cultural change and repeated practice opportunities for coaches. © 2017 American Society for Healthcare Risk Management of the American Hospital Association.

Autotrophs' challenge to Dynamic Energy Budget theory: Comment on ;Physics of metabolic organization; by Marko Jusup et al.

NASA Astrophysics Data System (ADS)

Geček, Sunčana

2017-03-01

Jusup and colleagues in the recent review on physics of metabolic organization [1] discuss in detail motivational considerations and common assumptions of Dynamic Energy Budget (DEB) theory, supply readers with a practical guide to DEB-based modeling, demonstrate the construction and dynamics of the standard DEB model, and illustrate several applications. The authors make a step forward from the existing literature by seamlessly bridging over the dichotomy between (i) thermodynamic foundations of the theory (which are often more accessible and understandable to physicists and mathematicians), and (ii) the resulting bioenergetic models (mostly used by biologists in real-world applications).

The early inflorescence of Arabidopsis thaliana demonstrates positional effects in floral organ growth and meristem patterning.

PubMed

Plackett, Andrew R G; Powers, Stephen J; Phillips, Andy L; Wilson, Zoe A; Hedden, Peter; Thomas, Stephen G

2018-06-01

Linear modelling approaches detected significant gradients in organ growth and patterning across early flowers of the Arabidopsis inflorescence and uncovered evidence of new roles for gibberellin in floral development. Most flowering plants, including the genetic model Arabidopsis thaliana, produce multiple flowers in sequence from a reproductive shoot apex to form a flower spike (inflorescence). The development of individual flowers on an Arabidopsis inflorescence has typically been considered as highly stereotypical and uniform, but this assumption is contradicted by the existence of mutants with phenotypes visible in early flowers only. This phenomenon is demonstrated by mutants partially impaired in the biosynthesis of the phytohormone gibberellin (GA), in which floral organ growth is retarded in the first flowers to be produced but has recovered spontaneously by the 10th flower. We presently lack systematic data from multiple flowers across the Arabidopsis inflorescence to explain such changes. Using mutants of the GA 20-OXIDASE (GA20ox) GA biosynthesis gene family to manipulate endogenous GA levels, we investigated the dynamics of changing floral organ growth across the early Arabidopsis inflorescence (flowers 1-10). Modelling of floral organ lengths identified a significant, GA-independent gradient of increasing stamen length relative to the pistil in the wild-type inflorescence that was separable from other, GA-dependent effects. It was also found that the first flowers exhibited unstable organ patterning in contrast to later flowers and that this instability was prolonged by exogenous GA treatment. These findings indicate that the development of individual flowers is influenced by hitherto unknown factors acting across the inflorescence and also suggest novel functions for GA in floral patterning.

How the Group Investigation Model and the Six-Mirror Model Changed Teachers' Roles and Teachers' and Students' Attitudes towards Diversity

ERIC Educational Resources Information Center

Damini, Marialuisa

2014-01-01

This paper is based on research that demonstrates the positive effects of the cooperative learning model Group Investigation (GI) and the Six-Mirror model on teacher effectiveness in organizing and scaffolding CL activities, and changing students' and teachers' views of diversity. We explain how the connection between the two models…

Simulation Modeling of Software Development Processes

NASA Technical Reports Server (NTRS)

Calavaro, G. F.; Basili, V. R.; Iazeolla, G.

1996-01-01

A simulation modeling approach is proposed for the prediction of software process productivity indices, such as cost and time-to-market, and the sensitivity analysis of such indices to changes in the organization parameters and user requirements. The approach uses a timed Petri Net and Object Oriented top-down model specification. Results demonstrate the model representativeness, and its usefulness in verifying process conformance to expectations, and in performing continuous process improvement and optimization.

Oscillatory network with self-organized dynamical connections for synchronization-based image segmentation.

PubMed

Kuzmina, Margarita; Manykin, Eduard; Surina, Irina

2004-01-01

An oscillatory network of columnar architecture located in 3D spatial lattice was recently designed by the authors as oscillatory model of the brain visual cortex. Single network oscillator is a relaxational neural oscillator with internal dynamics tunable by visual image characteristics - local brightness and elementary bar orientation. It is able to demonstrate either activity state (stable undamped oscillations) or "silence" (quickly damped oscillations). Self-organized nonlocal dynamical connections of oscillators depend on oscillator activity levels and orientations of cortical receptive fields. Network performance consists in transfer into a state of clusterized synchronization. At current stage grey-level image segmentation tasks are carried out by 2D oscillatory network, obtained as a limit version of the source model. Due to supplemented network coupling strength control the 2D reduced network provides synchronization-based image segmentation. New results on segmentation of brightness and texture images presented in the paper demonstrate accurate network performance and informative visualization of segmentation results, inherent in the model.

Human Skin 3D Bioprinting Using Scaffold-Free Approach.

PubMed

Pourchet, Léa J; Thepot, Amélie; Albouy, Marion; Courtial, Edwin J; Boher, Aurélie; Blum, Loïc J; Marquette, Christophe A

2017-02-01

Organ in vitro synthesis is one of the last bottlenecks between tissue engineering and transplantation of synthetic organs. Bioprinting has proven its capacity to produce 3D objects composed of living cells but highly organized tissues such as full thickness skin (dermis + epidermis) are rarely attained. The focus of the present study is to demonstrate the capability of a newly developed ink formulation and the use of an open source printer, for the production of a really complete skin model. Proofs are given through immunostaining and electronic microscopy that the bioprinted skin presents all characteristics of human skin, both at the molecular and macromolecular level. Finally, the printability of large skin objects is demonstrated with the printing of an adult-size ear. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Photonic crystals for improving light absorption in organic solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duché, D., E-mail: david.duche@im2np.fr; Le Rouzo, J.; Masclaux, C.

2015-02-07

We theoretically and experimentally study the structuration of organic solar cells in the shape of photonic crystal slabs. By taking advantage of the optical properties of photonic crystals slabs, we show the possibility to couple Bloch modes with very low group velocities in the active layer of the cells. These Bloch modes, also called slow Bloch modes (SBMs), allow increasing the lifetime of photons within the active layer. Finally, we present experimental demonstration performed by using nanoimprint to directly pattern the standard poly-3-hexylthiophène:[6,6]-phenyl-C61-butiryc acid methyl ester organic semiconductor blend in thin film form in the shape of a photonic crystalmore » able to couple SBMs. In agreement with the model, optical characterizations will demonstrate significant photonic absorption gains.« less

Dueling Scorecards: How Two Colleges Utilize the Popular Planning Method

ERIC Educational Resources Information Center

Ballentine, Howard; Eckles, Jay

2009-01-01

The Balanced Scorecard is a planning model used extensively in business to provide direction and accountability to an organization. Despite the demonstrated success of the model, it has not been widely used in higher education. This article compares and contrasts the use of the Balanced Scorecard by two small, private colleges. The article…

Critical role of LuxS in the virulence of Campylobacter jejuni in a guinea pig model of abortion.

PubMed

Plummer, Paul; Sahin, Orhan; Burrough, Eric; Sippy, Rachel; Mou, Kathy; Rabenold, Jessica; Yaeger, Mike; Zhang, Qijing

2012-02-01

Previous studies on Campylobacter jejuni have demonstrated the role of LuxS in motility, cytolethal distending toxin production, agglutination, and intestinal colonization; however, its direct involvement in virulence has not been reported. In this study, we demonstrate a direct role of luxS in the virulence of C. jejuni in two different animal hosts. The IA3902 strain, a highly virulent sheep abortion strain recently described by our laboratory, along with its isogenic luxS mutant and luxS complement strains, was inoculated by the oral route into both a pregnant guinea pig virulence model and a chicken colonization model. In both cases, the IA3902 luxS mutant demonstrated a complete loss of ability to colonize the intestinal tract. In the pregnant model, the mutant also failed to induce abortion, while the wild-type strain was highly abortifacient. Genetic complementation of the luxS gene fully restored the virulent phenotype in both models. Interestingly, when the organism was inoculated into guinea pigs by the intraperitoneal route, no difference in virulence (abortion induction) was observed between the luxS mutant and the wild-type strain, suggesting that the defect in virulence following oral inoculation is likely associated with a defect in colonization and/or translocation of the organism out of the intestine. These studies provide the first direct evidence that LuxS plays an important role in the virulence of C. jejuni using an in vivo model of natural disease.

Towards a paradigm shift in the modeling of soil organic carbon decomposition for earth system models

NASA Astrophysics Data System (ADS)

He, Yujie

Soils are the largest terrestrial carbon pools and contain approximately 2200 Pg of carbon. Thus, the dynamics of soil carbon plays an important role in the global carbon cycle and climate system. Earth System Models are used to project future interactions between terrestrial ecosystem carbon dynamics and climate. However, these models often predict a wide range of soil carbon responses and their formulations have lagged behind recent soil science advances, omitting key biogeochemical mechanisms. In contrast, recent mechanistically-based biogeochemical models that explicitly account for microbial biomass pools and enzyme kinetics that catalyze soil carbon decomposition produce notably different results and provide a closer match to recent observations. However, a systematic evaluation of the advantages and disadvantages of the microbial models and how they differ from empirical, first-order formulations in soil decomposition models for soil organic carbon is still needed. This dissertation consists of a series of model sensitivity and uncertainty analyses and identifies dominant decomposition processes in determining soil organic carbon dynamics. Poorly constrained processes or parameters that require more experimental data integration are also identified. This dissertation also demonstrates the critical role of microbial life-history traits (e.g. microbial dormancy) in the modeling of microbial activity in soil organic matter decomposition models. Finally, this study surveys and synthesizes a number of recently published microbial models and provides suggestions for future microbial model developments.

A nationwide survey of patient centered medical home demonstration projects.

PubMed

Bitton, Asaf; Martin, Carina; Landon, Bruce E

2010-06-01

The patient centered medical home has received considerable attention as a potential way to improve primary care quality and limit cost growth. Little information exists that systematically compares PCMH pilot projects across the country. Cross-sectional key-informant interviews. Leaders from existing PCMH demonstration projects with external payment reform. We used a semi-structured interview tool with the following domains: project history, organization and participants, practice requirements and selection process, medical home recognition, payment structure, practice transformation, and evaluation design. A total of 26 demonstrations in 18 states were interviewed. Current demonstrations include over 14,000 physicians caring for nearly 5 million patients. A majority of demonstrations are single payer, and most utilize a three component payment model (traditional fee for service, per person per month fixed payments, and bonus performance payments). The median incremental revenue per physician per year was $22,834 (range $720 to $91,146). Two major practice transformation models were identified--consultative and implementation of the chronic care model. A majority of demonstrations did not have well-developed evaluation plans. Current PCMH demonstration projects with external payment reform include large numbers of patients and physicians as well as a wide spectrum of implementation models. Key questions exist around the adequacy of current payment mechanisms and evaluation plans as public and policy interest in the PCMH model grows.

On being the right size: scaling effects in designing a human-on-a-chip

PubMed Central

Moraes, Christopher; Labuz, Joseph M.; Leung, Brendan M.; Inoue, Mayumi; Chun, Tae-Hwa; Takayama, Shuichi

2013-01-01

Developing a human-on-a-chip by connecting multiple model organ systems would provide an intermediate screen for therapeutic efficacy and toxic side effects of drugs prior to conducting expensive clinical trials. However, correctly designing individual organs and scaling them relative to each other to make a functional microscale human analog is challenging, and a generalized approach has yet to be identified. In this work, we demonstrate the importance of rational design of both the individual organ and its relationship with other organs, using a simple two-compartment system simulating insulin-dependent glucose uptake in adipose tissues. We demonstrate that inter-organ scaling laws depend on both the number of cells, and on the spatial arrangement of those cells within the microfabricated construct. We then propose a simple and novel inter-organ ‘metabolically-supported functional scaling’ approach predicated on maintaining in vivo cellular basal metabolic rates, by limiting resources available to cells on the chip. This approach leverages findings from allometric scaling models in mammals that limited resources in vivo prompts cells to behave differently than in resource-rich in vitro cultures. Although applying scaling laws directly to tissues can result in systems that would be quite challenging to implement, engineering workarounds may be used to circumvent these scaling issues. Specific workarounds discussed include the limited oxygen carrying capacity of cell culture media when used as a blood substitute and the ability to engineer non-physiological structures to augment organ function, to create the transport-accessible, yet resource-limited environment necessary for cells to mimic in vivo functionality. Furthermore, designing the structure of individual tissues in each organ compartment may be a useful strategy to bypass scaling concerns at the inter-organ level. PMID:23925524

The effect of dose heterogeneity on radiation risk in medical imaging.

PubMed

Samei, Ehsan; Li, Xiang; Chen, Baiyu; Reiman, Robert

2013-06-01

The current estimations of risk associated with medical imaging procedures rely on assessing the organ dose via direct measurements or simulation. The dose to each organ is assumed to be homogeneous. To take into account the differences in radiation sensitivities, the mean organ doses are weighted by a corresponding tissue-weighting coefficients provided by ICRP to calculate the effective dose, which has been used as a surrogate of radiation risk. However, those coefficients were derived under the assumption of a homogeneous dose distribution within each organ. That assumption is significantly violated in most medical-imaging procedures. In helical chest CT, for example, superficial organs (e.g. breasts) demonstrate a heterogeneous dose distribution, whereas organs on the peripheries of the irradiation field (e.g. liver) might possess a discontinuous dose profile. Projection radiography and mammography involve an even higher level of organ dose heterogeneity spanning up to two orders of magnitude. As such, mean dose or point measured dose values do not reflect the maximum energy deposited per unit volume of the organ. In this paper, the magnitude of the dose heterogeneity in both CT and projection X-ray imaging was reported, using Monte Carlo methods. The lung dose demonstrated factors of 1.7 and 2.2 difference between the mean and maximum dose for chest CT and radiography, respectively. The corresponding values for the liver were 1.9 and 3.5. For mammography and breast tomosynthesis, the difference between mean glandular dose and maximum glandular dose was 3.1. Risk models based on the mean dose were found to provide a reasonable reflection of cancer risk. However, for leukaemia, they were found to significantly under-represent the risk when the organ dose distribution is heterogeneous. A systematic study is needed to develop a risk model for heterogeneous dose distributions.

Self-Organizing Batteries

DTIC Science & Technology

2005-12-16

of these principles to a lithium ion battery , resulting in the demonstration of the first self-organized rechargeable battery. These accomplishments...spherical graphite widely used as a lithium ion battery anode, was used as the high-index endmember and was attached to an AFM cantilever. Its...resulting junctions could be stable under electrochemical conditions typical of lithium ion battery systems. We used PEG + LiClO 4 as our model solid

A cascaded QSAR model for efficient prediction of overall power conversion efficiency of all-organic dye-sensitized solar cells.

PubMed

Li, Hongzhi; Zhong, Ziyan; Li, Lin; Gao, Rui; Cui, Jingxia; Gao, Ting; Hu, Li Hong; Lu, Yinghua; Su, Zhong-Min; Li, Hui

2015-05-30

A cascaded model is proposed to establish the quantitative structure-activity relationship (QSAR) between the overall power conversion efficiency (PCE) and quantum chemical molecular descriptors of all-organic dye sensitizers. The cascaded model is a two-level network in which the outputs of the first level (JSC, VOC, and FF) are the inputs of the second level, and the ultimate end-point is the overall PCE of dye-sensitized solar cells (DSSCs). The model combines quantum chemical methods and machine learning methods, further including quantum chemical calculations, data division, feature selection, regression, and validation steps. To improve the efficiency of the model and reduce the redundancy and noise of the molecular descriptors, six feature selection methods (multiple linear regression, genetic algorithms, mean impact value, forward selection, backward elimination, and +n-m algorithm) are used with the support vector machine. The best established cascaded model predicts the PCE values of DSSCs with a MAE of 0.57 (%), which is about 10% of the mean value PCE (5.62%). The validation parameters according to the OECD principles are R(2) (0.75), Q(2) (0.77), and Qcv2 (0.76), which demonstrate the great goodness-of-fit, predictivity, and robustness of the model. Additionally, the applicability domain of the cascaded QSAR model is defined for further application. This study demonstrates that the established cascaded model is able to effectively predict the PCE for organic dye sensitizers with very low cost and relatively high accuracy, providing a useful tool for the design of dye sensitizers with high PCE. © 2015 Wiley Periodicals, Inc.

Segmentation of deformable organs from medical images using particle swarm optimization and nonlinear shape priors

NASA Astrophysics Data System (ADS)

Afifi, Ahmed; Nakaguchi, Toshiya; Tsumura, Norimichi

2010-03-01

In many medical applications, the automatic segmentation of deformable organs from medical images is indispensable and its accuracy is of a special interest. However, the automatic segmentation of these organs is a challenging task according to its complex shape. Moreover, the medical images usually have noise, clutter, or occlusion and considering the image information only often leads to meager image segmentation. In this paper, we propose a fully automated technique for the segmentation of deformable organs from medical images. In this technique, the segmentation is performed by fitting a nonlinear shape model with pre-segmented images. The kernel principle component analysis (KPCA) is utilized to capture the complex organs deformation and to construct the nonlinear shape model. The presegmentation is carried out by labeling each pixel according to its high level texture features extracted using the overcomplete wavelet packet decomposition. Furthermore, to guarantee an accurate fitting between the nonlinear model and the pre-segmented images, the particle swarm optimization (PSO) algorithm is employed to adapt the model parameters for the novel images. In this paper, we demonstrate the competence of proposed technique by implementing it to the liver segmentation from computed tomography (CT) scans of different patients.

Label-free detection of protein molecules secreted from an organ-on-a-chip model for drug toxicity assays

NASA Astrophysics Data System (ADS)

Morales, Andres W.; Zhang, Yu S.; Aleman, Julio; Alerasool, Parissa; Dokmeci, Mehmet R.; Khademhosseini, Ali; Ye, Jing Yong

2016-03-01

Clinical attrition is about 30% from failure of drug candidates due to toxic side effects, increasing the drug development costs significantly and slowing down the drug discovery process. This partly originates from the fact that the animal models do not accurately represent human physiology. Hence there is a clear unmet need for developing drug toxicity assays using human-based models that are complementary to traditional animal models before starting expensive clinical trials. Organ-on-a-chip techniques developed in recent years have generated a variety of human organ models mimicking different human physiological conditions. However, it is extremely challenging to monitor the transient and long-term response of the organ models to drug treatments during drug toxicity tests. First, when an organ-on-a-chip model interacts with drugs, a certain amount of protein molecules may be released into the medium due to certain drug effects, but the amount of the protein molecules is limited, since the organ tissue grown inside microfluidic bioreactors have minimum volume. Second, traditional fluorescence techniques cannot be utilized for real-time monitoring of the concentration of the protein molecules, because the protein molecules are continuously secreted from the tissue and it is practically impossible to achieve fluorescence labeling in the dynamically changing environment. Therefore, direct measurements of the secreted protein molecules with a label-free approach is strongly desired for organs-on-a-chip applications. In this paper, we report the development of a photonic crystal-based biosensor for label-free assays of secreted protein molecules from a liver-on-a-chip model. Ultrahigh detection sensitivity and specificity have been demonstrated.

A Model of Self-Organizing Head-Centered Visual Responses in Primate Parietal Areas

PubMed Central

Mender, Bedeho M. W.; Stringer, Simon M.

2013-01-01

We present a hypothesis for how head-centered visual representations in primate parietal areas could self-organize through visually-guided learning, and test this hypothesis using a neural network model. The model consists of a competitive output layer of neurons that receives afferent synaptic connections from a population of input neurons with eye position gain modulated retinal receptive fields. The synaptic connections in the model are trained with an associative trace learning rule which has the effect of encouraging output neurons to learn to respond to subsets of input patterns that tend to occur close together in time. This network architecture and synaptic learning rule is hypothesized to promote the development of head-centered output neurons during periods of time when the head remains fixed while the eyes move. This hypothesis is demonstrated to be feasible, and each of the core model components described is tested and found to be individually necessary for successful self-organization. PMID:24349064

Phenanthrene sorption with heterogeneous organic matter in a landfill aquifer material

USGS Publications Warehouse

Karapanagioti, H.K.; Sabatini, D.A.; Kleineidam, S.; Grathwohl, P.; Ligouis, B.

1999-01-01

Phenanthrene was used as a model chemical to study the sorption properties of Canadian River Alluvium aquifer material. Both equilibrium and kinetic sorption processes were evaluated through batch studies. The bulk sample was divided into subsamples with varying properties such as particle size, organic content, equilibration time, etc. in order to determine the effect of these properties on resulting sorption parameters. The data have been interpreted and the effect of experimental variables was quantified using the Freundlich isotherm model and a numerical solution of Fick's 2nd law in porous media. Microscopic organic matter characterization proved to be a valuable tool for explaining the results. Different organic matter properties and sorption mechanisms were observed for each soil subsample. Samples containing coal particles presented high Koc values. Samples with organic matter dominated by organic coatings on quartz grains presented low Koc values and contained a high percentage of fast sorption sites. The numerical solution of Fick's 2ndlaw requires the addition of two terms (fast and slow) in order to fit the kinetics of these heterogeneous samples properly. These results thus demonstrate the need for soil organic matter characterization in order to predict and explain the sorption properties of a soil sample containing heterogeneous organic matter and also the difficulty and complexity of modeling sorption in such samples.

Physiological motion modeling for organ-mounted robots.

PubMed

Wood, Nathan A; Schwartzman, David; Zenati, Marco A; Riviere, Cameron N

2017-12-01

Organ-mounted robots passively compensate heartbeat and respiratory motion. In model-guided procedures, this motion can be a significant source of information that can be used to aid in localization or to add dynamic information to static preoperative maps. Models for estimating periodic motion are proposed for both position and orientation. These models are then tested on animal data and optimal orders are identified. Finally, methods for online identification are demonstrated. Models using exponential coordinates and Euler-angle parameterizations are as accurate as models using quaternion representations, yet require a quarter fewer parameters. Models which incorporate more than four cardiac or three respiration harmonics are no more accurate. Finally, online methods estimate model parameters as accurately as offline methods within three respiration cycles. These methods provide a complete framework for accurately modelling the periodic deformation of points anywhere on the surface of the heart in a closed chest. Copyright © 2017 John Wiley & Sons, Ltd.

IT vendor selection model by using structural equation model & analytical hierarchy process

NASA Astrophysics Data System (ADS)

Maitra, Sarit; Dominic, P. D. D.

2012-11-01

Selecting and evaluating the right vendors is imperative for an organization's global marketplace competitiveness. Improper selection and evaluation of potential vendors can dwarf an organization's supply chain performance. Numerous studies have demonstrated that firms consider multiple criteria when selecting key vendors. This research intends to develop a new hybrid model for vendor selection process with better decision making. The new proposed model provides a suitable tool for assisting decision makers and managers to make the right decisions and select the most suitable vendor. This paper proposes a Hybrid model based on Structural Equation Model (SEM) and Analytical Hierarchy Process (AHP) for long-term strategic vendor selection problems. The five steps framework of the model has been designed after the thorough literature study. The proposed hybrid model will be applied using a real life case study to assess its effectiveness. In addition, What-if analysis technique will be used for model validation purpose.

Reconstructing spatial organizations of chromosomes through manifold learning

PubMed Central

Deng, Wenxuan; Hu, Hailin; Ma, Rui; Zhang, Sai; Yang, Jinglin; Peng, Jian; Kaplan, Tommy; Zeng, Jianyang

2018-01-01

Abstract Decoding the spatial organizations of chromosomes has crucial implications for studying eukaryotic gene regulation. Recently, chromosomal conformation capture based technologies, such as Hi-C, have been widely used to uncover the interaction frequencies of genomic loci in a high-throughput and genome-wide manner and provide new insights into the folding of three-dimensional (3D) genome structure. In this paper, we develop a novel manifold learning based framework, called GEM (Genomic organization reconstructor based on conformational Energy and Manifold learning), to reconstruct the three-dimensional organizations of chromosomes by integrating Hi-C data with biophysical feasibility. Unlike previous methods, which explicitly assume specific relationships between Hi-C interaction frequencies and spatial distances, our model directly embeds the neighboring affinities from Hi-C space into 3D Euclidean space. Extensive validations demonstrated that GEM not only greatly outperformed other state-of-art modeling methods but also provided a physically and physiologically valid 3D representations of the organizations of chromosomes. Furthermore, we for the first time apply the modeled chromatin structures to recover long-range genomic interactions missing from original Hi-C data. PMID:29408992

Reconstructing spatial organizations of chromosomes through manifold learning.

PubMed

Zhu, Guangxiang; Deng, Wenxuan; Hu, Hailin; Ma, Rui; Zhang, Sai; Yang, Jinglin; Peng, Jian; Kaplan, Tommy; Zeng, Jianyang

2018-05-04

Decoding the spatial organizations of chromosomes has crucial implications for studying eukaryotic gene regulation. Recently, chromosomal conformation capture based technologies, such as Hi-C, have been widely used to uncover the interaction frequencies of genomic loci in a high-throughput and genome-wide manner and provide new insights into the folding of three-dimensional (3D) genome structure. In this paper, we develop a novel manifold learning based framework, called GEM (Genomic organization reconstructor based on conformational Energy and Manifold learning), to reconstruct the three-dimensional organizations of chromosomes by integrating Hi-C data with biophysical feasibility. Unlike previous methods, which explicitly assume specific relationships between Hi-C interaction frequencies and spatial distances, our model directly embeds the neighboring affinities from Hi-C space into 3D Euclidean space. Extensive validations demonstrated that GEM not only greatly outperformed other state-of-art modeling methods but also provided a physically and physiologically valid 3D representations of the organizations of chromosomes. Furthermore, we for the first time apply the modeled chromatin structures to recover long-range genomic interactions missing from original Hi-C data.

Quiet swimming at low Reynolds number

NASA Astrophysics Data System (ADS)

Andersen, Anders; Wadhwa, Navish; Kiørboe, Thomas

2015-04-01

The stresslet provides a simple model of the flow created by a small, freely swimming and neutrally buoyant aquatic organism and shows that the far field fluid disturbance created by such an organism in general decays as one over distance squared. Here we discuss a quieter swimming mode that eliminates the stresslet component of the flow and leads to a faster spatial decay of the fluid disturbance described by a force quadrupole that decays as one over distance cubed. Motivated by recent experimental results on fluid disturbances due to small aquatic organisms, we demonstrate that a three-Stokeslet model of a swimming organism which uses breast stroke type kinematics is an example of such a quiet swimmer. We show that the fluid disturbance in both the near field and the far field is significantly reduced by appropriately arranging the propulsion apparatus, and we find that the far field power laws are valid surprisingly close to the organism. Finally, we discuss point force models as a general framework for hypothesis generation and experimental exploration of fluid mediated predator-prey interactions in the planktonic world.

Quiet swimming at low Reynolds number.

PubMed

Andersen, Anders; Wadhwa, Navish; Kiørboe, Thomas

2015-04-01

The stresslet provides a simple model of the flow created by a small, freely swimming and neutrally buoyant aquatic organism and shows that the far field fluid disturbance created by such an organism in general decays as one over distance squared. Here we discuss a quieter swimming mode that eliminates the stresslet component of the flow and leads to a faster spatial decay of the fluid disturbance described by a force quadrupole that decays as one over distance cubed. Motivated by recent experimental results on fluid disturbances due to small aquatic organisms, we demonstrate that a three-Stokeslet model of a swimming organism which uses breast stroke type kinematics is an example of such a quiet swimmer. We show that the fluid disturbance in both the near field and the far field is significantly reduced by appropriately arranging the propulsion apparatus, and we find that the far field power laws are valid surprisingly close to the organism. Finally, we discuss point force models as a general framework for hypothesis generation and experimental exploration of fluid mediated predator-prey interactions in the planktonic world.

Organ-on-a-chip platforms for studying drug delivery systems.

PubMed

Bhise, Nupura S; Ribas, João; Manoharan, Vijayan; Zhang, Yu Shrike; Polini, Alessandro; Massa, Solange; Dokmeci, Mehmet R; Khademhosseini, Ali

2014-09-28

Novel microfluidic tools allow new ways to manufacture and test drug delivery systems. Organ-on-a-chip systems - microscale recapitulations of complex organ functions - promise to improve the drug development pipeline. This review highlights the importance of integrating microfluidic networks with 3D tissue engineered models to create organ-on-a-chip platforms, able to meet the demand of creating robust preclinical screening models. Specific examples are cited to demonstrate the use of these systems for studying the performance of drug delivery vectors and thereby reduce the discrepancies between their performance at preclinical and clinical trials. We also highlight the future directions that need to be pursued by the research community for these proof-of-concept studies to achieve the goal of accelerating clinical translation of drug delivery nanoparticles. Copyright © 2014 Elsevier B.V. All rights reserved.

Modeling of static electrical properties in organic field-effect transistors

NASA Astrophysics Data System (ADS)

Xu, Yong; Minari, Takeo; Tsukagoshi, Kazuhito; Gwoziecki, Romain; Coppard, Romain; Benwadih, Mohamed; Chroboczek, Jan; Balestra, Francis; Ghibaudo, Gerard

2011-07-01

A modeling of organic field-effect transistors' (OFETs') electrical characteristics is presented. This model is based on a one-dimensional (1-D) Poisson's equation solution that solves the potential profile in the organic semiconducting film. Most importantly, it demonstrates that, due to the common open-surface configuration used in organic transistors, the conduction occurs in the film volume below threshold. This is because the potential at the free surface is not fixed to zero but rather rises also with the gate bias. The tail of carrier concentration at the free surface is therefore significantly modulated by the gate bias, which partially explains the gate-voltage dependent contact resistance. At the same time in the so-called subthreshold region, we observe a clear charge trapping from the difference between C-V and I-V measurements; hence a traps study by numerical simulation is also performed. By combining the analytical modeling and the traps analysis, the questions on the C-V and I-V characteristics are answered. Finally, the combined results obtained with traps fit well the experimental data in both pentacene and bis(triisopropylsilylethynyl)-pentacene OFETs.

Prediction of Partition Coefficients of Organic Compounds between SPME/PDMS and Aqueous Solution

PubMed Central

Chao, Keh-Ping; Lu, Yu-Ting; Yang, Hsiu-Wen

2014-01-01

Polydimethylsiloxane (PDMS) is commonly used as the coated polymer in the solid phase microextraction (SPME) technique. In this study, the partition coefficients of organic compounds between SPME/PDMS and the aqueous solution were compiled from the literature sources. The correlation analysis for partition coefficients was conducted to interpret the effect of their physicochemical properties and descriptors on the partitioning process. The PDMS-water partition coefficients were significantly correlated to the polarizability of organic compounds (r = 0.977, p < 0.05). An empirical model, consisting of the polarizability, the molecular connectivity index, and an indicator variable, was developed to appropriately predict the partition coefficients of 61 organic compounds for the training set. The predictive ability of the empirical model was demonstrated by using it on a test set of 26 chemicals not included in the training set. The empirical model, applying the straightforward calculated molecular descriptors, for estimating the PDMS-water partition coefficient will contribute to the practical applications of the SPME technique. PMID:24534804

A two component model for thermal emission from organic grains in Comet Halley

NASA Technical Reports Server (NTRS)

Chyba, Christopher; Sagan, Carl

1988-01-01

Observations of Comet Halley in the near infrared reveal a triple-peaked emission feature near 3.4 micrometer, characteristic of C-H stretching in hydrocarbons. A variety of plausible cometary materials exhibit these features, including the organic residue of irradiated candidate cometary ices (such as the residue of irradiated methane ice clathrate, and polycyclic aromatic hydrocarbons. Indeed, any molecule containing -CH3 and -CH2 alkanes will emit at 3.4 micrometer under suitable conditions. Therefore tentative identifications must rest on additional evidence, including a plausible account of the origins of the organic material, a plausible model for the infrared emission of this material, and a demonstration that this conjunction of material and model not only matches the 3 to 4 micrometer spectrum, but also does not yield additional emission features where none is observed. In the case of the residue of irradiated low occupancy methane ice clathrate, it is argued that the lab synthesis of the organic residue well simulates the radiation processing experienced by Comet Halley.

GLIMPSE: An integrated assessment model-based tool for ...

EPA Pesticide Factsheets

Dan Loughlin will describe the GCAM-USA integrated assessment model and how that model is being improved and integrated into the GLIMPSE decision support system. He will also demonstrate the application of the model to evaluate the emissions and health implications of hypothetical state-level renewable electricity standards. Introduce the GLIMPSE project to state and regional environmental modelers and analysts. Presented as part of the State Energy and Air Quality Group Webinar Series, which is organized by NESCAUM.

Organic High Electron Mobility Transistors Realized by 2D Electron Gas.

PubMed

Zhang, Panlong; Wang, Haibo; Yan, Donghang

2017-09-01

A key breakthrough in inorganic modern electronics is the energy-band engineering that plays important role to improve device performance or develop novel functional devices. A typical application is high electron mobility transistors (HEMTs), which utilizes 2D electron gas (2DEG) as transport channel and exhibits very high electron mobility over traditional field-effect transistors (FETs). Recently, organic electronics have made very rapid progress and the band transport model is demonstrated to be more suitable for explaining carrier behavior in high-mobility crystalline organic materials. Therefore, there emerges a chance for applying energy-band engineering in organic semiconductors to tailor their optoelectronic properties. Here, the idea of energy-band engineering is introduced and a novel device configuration is constructed, i.e., using quantum well structures as active layers in organic FETs, to realize organic 2DEG. Under the control of gate voltage, electron carriers are accumulated and confined at quantized energy levels, and show efficient 2D transport. The electron mobility is up to 10 cm 2 V -1 s -1 , and the operation mechanisms of organic HEMTs are also argued. Our results demonstrate the validity of tailoring optoelectronic properties of organic semiconductors by energy-band engineering, offering a promising way for the step forward of organic electronics. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Movement patterns of Tenebrio beetles demonstrate empirically that correlated-random-walks have similitude with a Lévy walk.

PubMed

Reynolds, Andy M; Leprêtre, Lisa; Bohan, David A

2013-11-07

Correlated random walks are the dominant conceptual framework for modelling and interpreting organism movement patterns. Recent years have witnessed a stream of high profile publications reporting that many organisms perform Lévy walks; movement patterns that seemingly stand apart from the correlated random walk paradigm because they are discrete and scale-free rather than continuous and scale-finite. Our new study of the movement patterns of Tenebrio molitor beetles in unchanging, featureless arenas provides the first empirical support for a remarkable and deep theoretical synthesis that unites correlated random walks and Lévy walks. It demonstrates that the two models are complementary rather than competing descriptions of movement pattern data and shows that correlated random walks are a part of the Lévy walk family. It follows from this that vast numbers of Lévy walkers could be hiding in plain sight.

Generic reactive transport codes as flexible tools to integrate soil organic matter degradation models with water, transport and geochemistry in soils

NASA Astrophysics Data System (ADS)

Jacques, Diederik; Gérard, Fréderic; Mayer, Uli; Simunek, Jirka; Leterme, Bertrand

2016-04-01

A large number of organic matter degradation, CO2 transport and dissolved organic matter models have been developed during the last decades. However, organic matter degradation models are in many cases strictly hard-coded in terms of organic pools, degradation kinetics and dependency on environmental variables. The scientific input of the model user is typically limited to the adjustment of input parameters. In addition, the coupling with geochemical soil processes including aqueous speciation, pH-dependent sorption and colloid-facilitated transport are not incorporated in many of these models, strongly limiting the scope of their application. Furthermore, the most comprehensive organic matter degradation models are combined with simplified representations of flow and transport processes in the soil system. We illustrate the capability of generic reactive transport codes to overcome these shortcomings. The formulations of reactive transport codes include a physics-based continuum representation of flow and transport processes, while biogeochemical reactions can be described as equilibrium processes constrained by thermodynamic principles and/or kinetic reaction networks. The flexibility of these type of codes allows for straight-forward extension of reaction networks, permits the inclusion of new model components (e.g.: organic matter pools, rate equations, parameter dependency on environmental conditions) and in such a way facilitates an application-tailored implementation of organic matter degradation models and related processes. A numerical benchmark involving two reactive transport codes (HPx and MIN3P) demonstrates how the process-based simulation of transient variably saturated water flow (Richards equation), solute transport (advection-dispersion equation), heat transfer and diffusion in the gas phase can be combined with a flexible implementation of a soil organic matter degradation model. The benchmark includes the production of leachable organic matter and inorganic carbon in the aqueous and gaseous phases, as well as different decomposition functions with first-order, linear dependence or nonlinear dependence on a biomass pool. In addition, we show how processes such as local bioturbation (bio-diffusion) can be included implicitly through a Fickian formulation of transport of soil organic matter. Coupling soil organic matter models with generic and flexible reactive transport codes offers a valuable tool to enhance insights into coupled physico-chemical processes at different scales within the scope of C-biogeochemical cycles, possibly linked with other chemical elements such as plant nutrients and pollutants.

76 FR 40898 - Final Priorities, Requirements, and Selection Criteria; Charter Schools Program (CSP) Grants for...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-12

... schools. (3) A multi-year financial and operating model for the organization, a demonstrated commitment of... school model and to expand the number of high-quality charter schools available to students across the... percent threshold in this priority is consistent with the average percentage of students in large urban...

Dubinin-Astakhov model for acetylene adsorption on metal-organic frameworks

NASA Astrophysics Data System (ADS)

Cheng, Peifu; Hu, Yun Hang

2016-07-01

Acetylene (C2H2) is explosive at a pressure above 29 psi, causing a safety issue for its storage and applications. C2H2 adsorption on metal-organic frameworks (MOFs) has been explored to solve the issue. However, a suitable isotherm equation for C2H2 adsorption on various MOFs has not been found. In this paper, it was demonstrated that Dubinin-Astakhov equation can be exploited as a general isotherm model to depict C2H2 adsorption on MOF-5, ZIF-8, HKUST-1, and MIL-53. In contrast, commonly used Langmuir and BET models exhibited their inapplicability for C2H2 adsorption on those MOFs.

Emergent Vortex Patterns in Systems of Self-Propelled, Chiral Particles

NASA Astrophysics Data System (ADS)

Huber, Lorenz; Denk, Jonas; Reithmann, Emanuel; Frey, Erwin

Self-organization of FtsZ polymers is vital for Z-ring assembly during bacterial cell division, and has been studied using reconstituted in vitro model systems. Employing Brownian dynamics simulations and a Boltzmann approach, we model FtsZ polymers as active particles moving along chiral circular paths. With both theoretical approaches we find self-organization into vortex structures and characterize different states in parameter states. Our work demonstrates that these patterns are robust and are generic for active chiral matter. Moreover, we show that the dynamics at the onset of pattern formation is described by a generalized complex Ginzburg-Landau equation.

Organization model for Mobile Wireless Sensor Networks inspired in Artificial Bee Colony

NASA Astrophysics Data System (ADS)

Freire Roberto, Guilherme; Castilho Maschi, Luis Fernando; Pigatto, Daniel Fernando; Jaquie Castelo Branco, Kalinka Regina Lucas; Alves Neves, Leandro; Montez, Carlos; Sandro Roschildt Pinto, Alex

2015-01-01

The purpose of this study is to find a self-organizing model for MWSN based on bee colonies in order to reduce the number of messages transmitted among nodes, and thus reduce the overall consumption energy while maintaining the efficiency of message delivery. The results obtained in this article are originated from simulations carried out with SINALGO software, which demonstrates the effectiveness of the proposed approach. The BeeAODV (Bee Ad-Hoc On Demand Distance Vector) proposed in this paper allows to considerably reduce message exchanges whether compared to AODV (Ad-Hoc On Demand Distance Vector).

Organic condensation: A vital link connecting aerosol formation to climate forcing (Invited)

NASA Astrophysics Data System (ADS)

Riipinen, I.; Pierce, J. R.; Yli-Juuti, T.; Nieminen, T.; Häkkinen, S.; Ehn, M.; Junninen, H.; Lehtipalo, K.; Petdjd, T. T.; Slowik, J. G.; Chang, R. Y.; Shantz, N. C.; Abbatt, J.; Leaitch, W. R.; Kerminen, V.; Worsnop, D. R.; Pandis, S. N.; Donahue, N. M.; Kulmala, M. T.

2010-12-01

Aerosol-cloud interactions represent the largest uncertainty in calculations of Earth’s radiative forcing. Number concentrations of atmospheric aerosol particles are in the core of this uncertainty, as they govern the numbers of cloud condensation nuclei (CCN) and influence the albedo and lifetime of clouds. Aerosols also impair air quality through their adverse effects on atmospheric visibility and human health. The ultrafine fraction (<100 nm) of atmospheric aerosol particles often dominates the total aerosol numbers, and nucleation of atmospheric vapours is one of the most important sources of these particles. To have climatic relevance, however, the freshly-nucleated particles need to grow in size, and consequently their climatic importance remains to be quantified (see Fig. 1). We combine observations from two continental sites (Egbert, Canada and Hyytiälä, Finland) to show that condensation of organic vapours is a crucial factor governing the lifetimes and climatic importance of the smallest atmospheric particles. We demonstrate that state-of-the-science organic gas-particle partitioning models fail to reproduce the observations; we propose a new modelling approach that is consistent with the measurements. Finally, we demonstrate the large sensitivity of climatic forcing of atmospheric aerosols to these interactions between organic vapours and the smallest atmospheric nanoparticles - highlighting the need for representing this process in global climate models. Figure 1. Organic emissions and the dynamic processes governing the climatic importance of ultrafine aerosol. Condensable vapours are produced upon oxidation of volatile organic compounds (VOCs) and can 1) nucleate to form new small particles; 2) grow freshly formed particles to larger sizes and increase their probability to serve as CCN; 3) condense on the background aerosol (> 100 nm) and enhance the loss of ultrafine particles. Primary organic aerosol (POA) contributes to the large end of the aerosol size distribution, enhancing the scavenging of the ultrafine particles.

Automated tracking, segmentation and trajectory classification of pelvic organs on dynamic MRI.

PubMed

Nekooeimehr, Iman; Lai-Yuen, Susana; Bao, Paul; Weitzenfeld, Alfredo; Hart, Stuart

2016-08-01

Pelvic organ prolapse is a major health problem in women where pelvic floor organs (bladder, uterus, small bowel, and rectum) fall from their normal position and bulge into the vagina. Dynamic Magnetic Resonance Imaging (DMRI) is presently used to analyze the organs' movements from rest to maximum strain providing complementary support for diagnosis. However, there is currently no automated or quantitative approach to measure the movement of the pelvic organs and their correlation with the severity of prolapse. In this paper, a two-stage method is presented to automatically track and segment pelvic organs on DMRI followed by a multiple-object trajectory classification method to improve the diagnosis of pelvic organ prolapse. Organs are first tracked using particle filters and K-means clustering with prior information. Then, they are segmented using the convex hull of the cluster of particles. Finally, the trajectories of the pelvic organs are modeled using a new Coupled Switched Hidden Markov Model (CSHMM) to classify the severity of pelvic organ prolapse. The tracking and segmentation results are validated using Dice Similarity Index (DSI) whereas the classification results are compared with two manual clinical measurements. Results demonstrate that the presented method is able to automatically track and segment pelvic organs with a DSI above 82% for 26 out of 46 cases and DSI above 75% for all 46 tested cases. The accuracy of the trajectory classification model is also better than current manual measurements.

Overview of ARPA low-cost ceramic composites (LC{sup 3}) program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adler, P.N.

1996-12-31

Grumman is currently leading an approximate $10M ARPA cost-shared program aimed at developing low-cost fabrication methodology for manufacturing ceramic matrix composite (CMC) structural components. One of the program goals is to demonstrate the effectiveness of an advanced materials partnership. A vertically integrated collaboration now exists that combines the talents of three large private sector organizations, two smaller private sector organizations, three universities, and three federal government laboratories. Work in progress involves preceramic polymer (Blackglas{trademark}) CMC materials technology, RTM and pyrolysis process modeling & simulation, and utilization of low-cost approaches for fabricating a CMC demonstration engine seal component. This paper reviewsmore » the program organization, functioning, and some of the highlights of the technical work, which is of interest to the DoD as well as the commercial sector.« less

Brain drain? An examination of stereotype threat effects during training on knowledge acquisition and organizational effectiveness.

PubMed

Grand, James A

2017-02-01

Stereotype threat describes a situation in which individuals are faced with the risk of upholding a negative stereotype about their subgroup based on their actions. Empirical work in this area has primarily examined the impact of negative stereotypes on performance for threatened individuals. However, this body of research seldom acknowledges that performance is a function of learning-which may also be impaired by pervasive group stereotypes. This study presents evidence from a 3-day self-guided training program demonstrating that stereotype threat impairs acquisition of cognitive learning outcomes for females facing a negative group stereotype. Using hierarchical Bayesian modeling, results revealed that stereotyped females demonstrated poorer declarative knowledge acquisition, spent less time reflecting on learning activities, and developed less efficiently organized knowledge structures compared with females in a control condition. Findings from a Bayesian mediation model also suggested that despite stereotyped individuals "working harder" to perform well, their underachievement was largely attributable to failures in learning to "work smarter." Building upon these empirical results, a computational model and computer simulation is also presented to demonstrate the practical significance of stereotype-induced impairments to learning on the development of an organization's human capital resources and capabilities. The simulation results show that even the presence of small effects of stereotype threat during learning/training have the potential to exert a significant negative impact on an organization's performance potential. Implications for future research and practice examining stereotype threat during learning are discussed. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Multi-scale Modeling of Chromosomal DNA in Living Cells

NASA Astrophysics Data System (ADS)

Spakowitz, Andrew

The organization and dynamics of chromosomal DNA play a pivotal role in a range of biological processes, including gene regulation, homologous recombination, replication, and segregation. Establishing a quantitative theoretical model of DNA organization and dynamics would be valuable in bridging the gap between the molecular-level packaging of DNA and genome-scale chromosomal processes. Our research group utilizes analytical theory and computational modeling to establish a predictive theoretical model of chromosomal organization and dynamics. In this talk, I will discuss our efforts to develop multi-scale polymer models of chromosomal DNA that are both sufficiently detailed to address specific protein-DNA interactions while capturing experimentally relevant time and length scales. I will demonstrate how these modeling efforts are capable of quantitatively capturing aspects of behavior of chromosomal DNA in both prokaryotic and eukaryotic cells. This talk will illustrate that capturing dynamical behavior of chromosomal DNA at various length scales necessitates a range of theoretical treatments that accommodate the critical physical contributions that are relevant to in vivo behavior at these disparate length and time scales. National Science Foundation, Physics of Living Systems Program (PHY-1305516).

Origin of Complexity in Multicellular Organisms

NASA Astrophysics Data System (ADS)

Furusawa, Chikara; Kaneko, Kunihiko

2000-06-01

Through extensive studies of dynamical system modeling cellular growth and reproduction, we find evidence that complexity arises in multicellular organisms naturally through evolution. Without any elaborate control mechanism, these systems can exhibit complex pattern formation with spontaneous cell differentiation. Such systems employ a ``cooperative'' use of resources and maintain a larger growth speed than simple cell systems, which exist in a homogeneous state and behave ``selfishly.'' The relevance of the diversity of chemicals and reaction dynamics to the growth of a multicellular organism is demonstrated. Chaotic biochemical dynamics are found to provide the multipotency of stem cells.

Achieving Weak Light Response with Plasmonic Nanogold-Decorated Organic Phototransistors.

PubMed

Luo, Xiao; Du, Lili; Liang, Yuanlong; Zhao, Feiyu; Lv, Wenli; Xu, Kun; Wang, Ying; Peng, Yingquan

2018-05-09

Weak light response of organic photodetectors has fascinating potentials in fields of modern science and technology. However, their photoresponsivity is hindered by poor photocarrier excitation and transport. Decorating active-layer surface with plasmonic nanometals is considered a viable strategy to address this issue. Here, we demonstrate a plasmonic nanogold decorated organic phototransistor achieving remarkable enhancement of photoresponsivity. Meanwhile, the photoresponsive range is broadened by 4 orders of magnitude. The proposed design is substantiated by a schematic energy level model combined with theoretical simulation analysis, enabling the development of the advanced optoelectronics.

The phase model of burnout and employee turnover.

PubMed

Goodman, Eric A; Boss, R Wayne

2002-01-01

This study explores the phase model of burnout and investigates its relationship to actual turnover in a hospital. The results indicate that employees who turnover have significantly higher burnout phase scores that those who stay in the organization. A further comparison of voluntary and involuntary turnover demonstrates that there is no significant differences on burnout phase scores. The findings lend support to the usefulness of the phase model of burnout.

Issues with RNA-seq analysis in non-model organisms: A salmonid example.

PubMed

Sundaram, Arvind; Tengs, Torstein; Grimholt, Unni

2017-10-01

High throughput sequencing (HTS) is useful for many purposes as exemplified by the other topics included in this special issue. The purpose of this paper is to look into the unique challenges of using this technology in non-model organisms where resources such as genomes, functional genome annotations or genome complexity provide obstacles not met in model organisms. To describe these challenges, we narrow our scope to RNA sequencing used to study differential gene expression in response to pathogen challenge. As a demonstration species we chose Atlantic salmon, which has a sequenced genome with poor annotation and an added complexity due to many duplicated genes. We find that our RNA-seq analysis pipeline deciphers between duplicates despite high sequence identity. However, annotation issues provide problems in linking differentially expressed genes to pathways. Also, comparing results between approaches and species are complicated due to lack of standardized annotation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Beating-heart registration for organ-mounted robots.

PubMed

Wood, Nathan A; Schwartzman, David; Passineau, Michael J; Moraca, Robert J; Zenati, Marco A; Riviere, Cameron N

2018-03-06

Organ-mounted robots address the problem of beating-heart surgery by adhering to the heart, passively providing a platform that approaches zero relative motion. Because of the quasi-periodic deformation of the heart due to heartbeat and respiration, registration must address not only spatial registration but also temporal registration. Motion data were collected in the porcine model in vivo (N = 6). Fourier series models of heart motion were developed. By comparing registrations generated using an iterative closest-point approach at different phases of respiration, the phase corresponding to minimum registration distance is identified. The spatiotemporal registration technique presented here reduces registration error by an average of 4.2 mm over the 6 trials, in comparison with a more simplistic static registration that merely averages out the physiological motion. An empirical metric for spatiotemporal registration of organ-mounted robots is defined and demonstrated using data from animal models in vivo. Copyright © 2018 John Wiley & Sons, Ltd.

Modeling ultrafast exciton migration within the electron donor domains of bulk heterojunction organic photovoltaics

DOE PAGES

Bednarz, Mateusz; Lapin, Joel; McGillicuddy, Ryan; ...

2017-02-21

Recent experimental studies revealed that charge carriers harvested by bulk heterojunction organic photovoltaics can be collected on ultrafast time scales. To investigate ultrafast exciton mobility, we construct simple, nonatomistic models of a common polymeric electron donor material. We first explore the relationship between the magnitude of energetic noise in the model Hamiltonian and the spatial extent of resulting eigenstates. We then employ a quantum master equation approach to simulate migration of chromophore-localized initial excited states. Excitons initially localized on a single chromophore at the center of the model delocalize down polymer chains and across pi-stacked chromophores through a coherent, wavelikemore » mechanism during the first few tens of femtoseconds. We explore the dependence of this coherent delocalization on coupling strength and on the magnitude of energetic noise. At longer times we observe continued migration toward a uniform population distribution that proceeds through an incoherent, diffusive mechanism. A series of simulations modeling exciton harvesting in domains of varying size demonstrates that smaller domains enhance ultrafast exciton harvesting yield. Finally, our nonatomistic model falls short of quantitative accuracy but demonstrates that excitons are mobile within electron donor domains on ultrafast time scales and that coherent exciton transport can enhance ultrafast exciton harvesting.« less

Modeling ultrafast exciton migration within the electron donor domains of bulk heterojunction organic photovoltaics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bednarz, Mateusz; Lapin, Joel; McGillicuddy, Ryan

Recent experimental studies revealed that charge carriers harvested by bulk heterojunction organic photovoltaics can be collected on ultrafast time scales. To investigate ultrafast exciton mobility, we construct simple, nonatomistic models of a common polymeric electron donor material. We first explore the relationship between the magnitude of energetic noise in the model Hamiltonian and the spatial extent of resulting eigenstates. We then employ a quantum master equation approach to simulate migration of chromophore-localized initial excited states. Excitons initially localized on a single chromophore at the center of the model delocalize down polymer chains and across pi-stacked chromophores through a coherent, wavelikemore » mechanism during the first few tens of femtoseconds. We explore the dependence of this coherent delocalization on coupling strength and on the magnitude of energetic noise. At longer times we observe continued migration toward a uniform population distribution that proceeds through an incoherent, diffusive mechanism. A series of simulations modeling exciton harvesting in domains of varying size demonstrates that smaller domains enhance ultrafast exciton harvesting yield. Finally, our nonatomistic model falls short of quantitative accuracy but demonstrates that excitons are mobile within electron donor domains on ultrafast time scales and that coherent exciton transport can enhance ultrafast exciton harvesting.« less

Science Notes.

ERIC Educational Resources Information Center

School Science Review, 1985

1985-01-01

Presents 23 experiments, demonstrations, activities, and computer programs in biology, chemistry, and physics. Topics include lead in petrol, production of organic chemicals, reduction of water, enthalpy, X-ray diffraction model, nuclear magnetic resonance spectroscopy, computer simulation for additive mixing of colors, Archimedes Principle, and…

Characterization of the geology, geochemistry, hydrology and microbiology of the in-situ air stripping demonstration site at the Savannah River Site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eddy, C.A.; Looney, B.B.; Dougherty, J.M.

1991-05-01

The Savannah River Site is the location of an Integrated Demonstration Project designed to evaluate innovative remediation technologies for environmental restoration at sites contaminated with volatile organic contaminants. This demonstration utilizes directionally drilled horizontal wells to deliver gases and extract contaminants from the subsurface. Phase I of the Integrated Demonstration focused on the application and development of in-situ air stripping technologies to remediate soils and sediments above and below the water table as well as groundwater contaminated with volatile organic contaminants. The objective of this report is to provide baseline information on the geology, geochemistry, hydrology, and microbiology of themore » demonstration site prior to the test. The distribution of contaminants in soils and sediments in the saturated zone and groundwater is emphasized. These data will be combined with data collected after the demonstration in order to evaluate the effectiveness of in-situ air stripping. New technologies for environmental characterization that were evaluated include depth discrete groundwater sampling (HydroPunch) and three-dimensional modeling of contaminant data.« less

Assessment of soil organic carbon stocks under future climate and land cover changes in Europe.

PubMed

Yigini, Yusuf; Panagos, Panos

2016-07-01

Soil organic carbon plays an important role in the carbon cycling of terrestrial ecosystems, variations in soil organic carbon stocks are very important for the ecosystem. In this study, a geostatistical model was used for predicting current and future soil organic carbon (SOC) stocks in Europe. The first phase of the study predicts current soil organic carbon content by using stepwise multiple linear regression and ordinary kriging and the second phase of the study projects the soil organic carbon to the near future (2050) by using a set of environmental predictors. We demonstrate here an approach to predict present and future soil organic carbon stocks by using climate, land cover, terrain and soil data and their projections. The covariates were selected for their role in the carbon cycle and their availability for the future model. The regression-kriging as a base model is predicting current SOC stocks in Europe by using a set of covariates and dense SOC measurements coming from LUCAS Soil Database. The base model delivers coefficients for each of the covariates to the future model. The overall model produced soil organic carbon maps which reflect the present and the future predictions (2050) based on climate and land cover projections. The data of the present climate conditions (long-term average (1950-2000)) and the future projections for 2050 were obtained from WorldClim data portal. The future climate projections are the recent climate projections mentioned in the Fifth Assessment IPCC report. These projections were extracted from the global climate models (GCMs) for four representative concentration pathways (RCPs). The results suggest an overall increase in SOC stocks by 2050 in Europe (EU26) under all climate and land cover scenarios, but the extent of the increase varies between the climate model and emissions scenarios. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

[Generation of functional organs from pluripotent stem cells].

PubMed

Miyamoto, Tatsuyuki; Nakauchi, Hiromitsu

2015-10-01

Hematopoietic stem cells (HSCs) have played a major role in stem cell biology, providing many conceptual ideas and models. Among them is the concept of the "niche", a special bone-marrow microenvironment that by exchanging cues regulates stem-cell fate. The HSC niche also plays an important role in HSC transplantation. Successful engraftment of donor HSCs depends on myeloablative pretreatment to empty the niche. The concept of the stem-cell niche has now been extended to the generation of organs. We postulated that an empty "organ niche" exists in a developing animal when development of an organ is genetically disabled. This organ niche should be developmentally compensated by blastocyst complementation using wild-type primary stem cells (PSCs). We proved the principle of organogenesis from xenogeneic PSCs in an embryo unable to form a specific organ, demonstrating the generation of functionally normal rat pancreas by injecting rat PSCs into pancreatogenesis-disabled mouse embryos. This principle has held in pigs. When pancreatogenesis-disabled pig embryos underwent complementation with blastomeres from wild-type pig embryos to produce chimeric pigs, the chimeras had normal pancreata and survived to adulthood. Demonstration of the generation of a functional organ from PSCs in pigs is a very important step toward generation of human cells, tissues, and organs from individual patients' own PSCs in large animals.

Using 3D modeling techniques to enhance teaching of difficult anatomical concepts

PubMed Central

Pujol, Sonia; Baldwin, Michael; Nassiri, Joshua; Kikinis, Ron; Shaffer, Kitt

2016-01-01

Rationale and Objectives Anatomy is an essential component of medical education as it is critical for the accurate diagnosis in organs and human systems. The mental representation of the shape and organization of different anatomical structures is a crucial step in the learning process. The purpose of this pilot study is to demonstrate the feasibility and benefits of developing innovative teaching modules for anatomy education of first-year medical students based on 3D reconstructions from actual patient data. Materials and Methods A total of 196 models of anatomical structures from 16 anonymized CT datasets were generated using the 3D Slicer open-source software platform. The models focused on three anatomical areas: the mediastinum, the upper abdomen and the pelvis. Online optional quizzes were offered to first-year medical students to assess their comprehension in the areas of interest. Specific tasks were designed for students to complete using the 3D models. Results Scores of the quizzes confirmed a lack of understanding of 3D spatial relationships of anatomical structures despite standard instruction including dissection. Written task material and qualitative review by students suggested that interaction with 3D models led to a better understanding of the shape and spatial relationships among structures, and helped illustrate anatomical variations from one body to another. Conclusion The study demonstrates the feasibility of one possible approach to the generation of 3D models of the anatomy from actual patient data. The educational materials developed have the potential to supplement the teaching of complex anatomical regions and help demonstrate the anatomic variation among patients. PMID:26897601

A neural model of figure-ground organization.

PubMed

Craft, Edward; Schütze, Hartmut; Niebur, Ernst; von der Heydt, Rüdiger

2007-06-01

Psychophysical studies suggest that figure-ground organization is a largely autonomous process that guides--and thus precedes--allocation of attention and object recognition. The discovery of border-ownership representation in single neurons of early visual cortex has confirmed this view. Recent theoretical studies have demonstrated that border-ownership assignment can be modeled as a process of self-organization by lateral interactions within V2 cortex. However, the mechanism proposed relies on propagation of signals through horizontal fibers, which would result in increasing delays of the border-ownership signal with increasing size of the visual stimulus, in contradiction with experimental findings. It also remains unclear how the resulting border-ownership representation would interact with attention mechanisms to guide further processing. Here we present a model of border-ownership coding based on dedicated neural circuits for contour grouping that produce border-ownership assignment and also provide handles for mechanisms of selective attention. The results are consistent with neurophysiological and psychophysical findings. The model makes predictions about the hypothetical grouping circuits and the role of feedback between cortical areas.

OCEANFILMS-2: Representing coadsorption of saccharides in marine films and potential impacts on modeled marine aerosol chemistry

NASA Astrophysics Data System (ADS)

Burrows, Susannah M.; Gobrogge, Eric; Fu, Li; Link, Katie; Elliott, Scott M.; Wang, Hongfei; Walker, Rob

2016-08-01

Here we show that the addition of chemical interactions between soluble monosaccharides and an insoluble lipid surfactant monolayer improves agreement of modeled sea spray chemistry with observed marine aerosol chemistry. In particular, the alkane:hydroxyl mass ratio in modeled sea spray organic matter is reduced from a median of 2.73 to a range of 0.41-0.69, reducing the discrepancy with previous Fourier transform infrared spectroscopy (FTIR) observations of clean marine aerosol (ratio: 0.24-0.38). The overall organic fraction of submicron sea spray also increases, allowing organic mass fractions in the range 0.5-0.7 for submicron sea spray particles over highly active phytoplankton blooms. Sum frequency generation experiments support the modeling approach by demonstrating that soluble monosaccharides can strongly adsorb to a lipid monolayer likely via Coulomb interactions under appropriate conditions. These laboratory findings motivate further research to determine the relevance of coadsorption mechanisms for real-world, sea spray aerosol production.

Growth and modelling of spherical crystalline morphologies of molecular materials

NASA Astrophysics Data System (ADS)

Shalev, O.; Biswas, S.; Yang, Y.; Eddir, T.; Lu, W.; Clarke, R.; Shtein, M.

2014-10-01

Crystalline, yet smooth, sphere-like morphologies of small molecular compounds are desirable in a wide range of applications but are very challenging to obtain using common growth techniques, where either amorphous films or faceted crystallites are the norm. Here we show solvent-free, guard flow-assisted organic vapour jet printing of non-faceted, crystalline microspheroids of archetypal small molecular materials used in organic electronic applications. We demonstrate how process parameters control the size distribution of the spheroids and propose an analytical model and a phase diagram predicting the surface morphology evolution of different molecules based on processing conditions, coupled with the thermophysical and mechanical properties of the molecules. This experimental approach opens a path for exciting applications of small molecular organic compounds in optical coatings, textured surfaces with controlled wettability, pharmaceutical and food substance printing and others, where thick organic films and particles with high surface area are needed.

An approach to collective behavior in cell cultures: modeling and analysis of ECIS data

NASA Astrophysics Data System (ADS)

Rabson, David; Lafalce, Evan; Lovelady, Douglas; Lo, Chun-Min

2011-03-01

We review recent results in which statistical measures of noise in ECIS data distinguished healthy cell cultures from cancerous or poisoned ones: after subtracting the ``signal,'' the 1 /fα noise in the healthy cultures shows longer short-time and long-time correlations. We discuss application of an artificial neural network to detect the cancer signal, and we demonstrate a computational model of cell-cell communication that produces signals similar to those of the experimental data. The simulation is based on the q -state Potts model with inspiration from the Bak-Tang-Wiesenfeld sand-pile model. We view the level of organization larger than cells but smaller than organs or tissues as a kind of ``mesoscopic'' biological physics, in which few-body interactions dominate, and the experiments and computational model as ways of exploring this regime.

Investigation of a tissue engineered tendon model by PS-OCT

NASA Astrophysics Data System (ADS)

Yang, Ying; Ahearne, Mark; Wimpenny, Ian; Guijarro-Leach, Juan; Torbet, Jim

2010-02-01

A few native tissues, such as tendon, skin and eye, possess highly organized collagenous matrices. In particular, the collagen fibers in tendon are organized into a hierarchical and unidirectional format, which gives rise to the high tissuespecific mechanical properties. This organization has been clearly revealed by a conventional polarized light microscope. The newly developed polarization-sensitive optical coherence tomography (PS-OCT) technique allows non-invasive visualization of birefringence images arising from orientated structures in a three dimensional format. Our previous studies of native tendon and tissue engineered tendon by PS-OCT demonstrate that tissue engineered tendon has a far less perfect collagen fiber organization than native tendon even under dynamic culture conditions. The purpose of this study is to use PS-OCT to assess the relationship between the degree of birefringence, collagen concentration and fiber density in model tendon tissues. The model tissue is constructed from an aligned collagen hydrogel and aligned polyester nanofibers. The effects of the diameter and density of the nanofibers and the collagen concentration in the model have been investigated. The alignment of collagen fibrils is induced by application of a high magnetic field during fibrillogenesis while aligned polyester nanofibers are manufactured using the electrospinning technique. It is found that the collagen concentration, the density and size of nanofiber bundles are the key parameters to produce birefringence in OCT images. The perfectly aligned collagen hydrogel with concentration as high as 4 mg/ml does not exhibit a birefringence image until the hydrogel has been compressed and concentrated. Aligned nanofiber bundles have demonstrated marginal birefringence in the absence of the collagen matrix. These studies enhance our understanding of how to control and optimize the parameters in tendon tissue engineering.

Accurate Induction Energies for Small Organic Molecules. 2. Development and Testing of Distributed Polarizability Models against SAPT(DFT) Energies.

PubMed

Misquitta, Alston J; Stone, Anthony J; Price, Sarah L

2008-01-01

In part 1 of this two-part investigation we set out the theoretical basis for constructing accurate models of the induction energy of clusters of moderately sized organic molecules. In this paper we use these techniques to develop a variety of accurate distributed polarizability models for a set of representative molecules that include formamide, N-methyl propanamide, benzene, and 3-azabicyclo[3.3.1]nonane-2,4-dione. We have also explored damping, penetration, and basis set effects. In particular, we have provided a way to treat the damping of the induction expansion. Different approximations to the induction energy are evaluated against accurate SAPT(DFT) energies, and we demonstrate the accuracy of our induction models on the formamide-water dimer.

Learning-based stochastic object models for characterizing anatomical variations

NASA Astrophysics Data System (ADS)

Dolly, Steven R.; Lou, Yang; Anastasio, Mark A.; Li, Hua

2018-03-01

It is widely known that the optimization of imaging systems based on objective, task-based measures of image quality via computer-simulation requires the use of a stochastic object model (SOM). However, the development of computationally tractable SOMs that can accurately model the statistical variations in human anatomy within a specified ensemble of patients remains a challenging task. Previously reported numerical anatomic models lack the ability to accurately model inter-patient and inter-organ variations in human anatomy among a broad patient population, mainly because they are established on image data corresponding to a few of patients and individual anatomic organs. This may introduce phantom-specific bias into computer-simulation studies, where the study result is heavily dependent on which phantom is used. In certain applications, however, databases of high-quality volumetric images and organ contours are available that can facilitate this SOM development. In this work, a novel and tractable methodology for learning a SOM and generating numerical phantoms from a set of volumetric training images is developed. The proposed methodology learns geometric attribute distributions (GAD) of human anatomic organs from a broad patient population, which characterize both centroid relationships between neighboring organs and anatomic shape similarity of individual organs among patients. By randomly sampling the learned centroid and shape GADs with the constraints of the respective principal attribute variations learned from the training data, an ensemble of stochastic objects can be created. The randomness in organ shape and position reflects the learned variability of human anatomy. To demonstrate the methodology, a SOM of an adult male pelvis is computed and examples of corresponding numerical phantoms are created.

Marine products with anti-protozoal activity: a review.

PubMed

García, Marley; Monzote, Lianet

2014-01-01

The marine organisms are a rich source of varied natural products with unique functionality. A variety of natural products of new molecular structures with diverse biological activities have been reported from marine flora and fauna for treatment and/or prevention of human diseases. The present review briefly illustrates current status of marine products as antiprotozoal agents. The in vitro and in vivo studies of marine algae, invertebrates and micro-organism against different protozoa parasites are included. The marine products studied, according to international criterions for selection of more promisory products in the different models reported, demonstrated their potentialities as antiprozoal agents. Herein, the interest of scientific community to search new alternatives from marine environment has been demonstrated.

Alternative arrangements for the delivery of eye care services within staff model managed care organizations.

PubMed

Soroka, Mort; Reis, Lesley; Krumholz, David; Krasner, Mel; Portello, Joan

2003-11-01

Eye care services, though accounting for only a small fraction of healthcare costs, encompass a unique spectrum of professional staffing options that can enhance efficiency and decrease costs within staff model managed care organizations. This study was designed to describe and assess alternative staffing arrangements and cost implications for the delivery of eye care services by optometrists, ophthalmologists, and primary care physicians within staff model managed care organizations. The clinical records of individual patients--rather than administrative and billing files--at three managed care organizations are the principal source of information. Clinical auditors extracted data on ambulatory eye care services provided for conjunctivitis, corneal abrasion/erosion, cataract, diabetic retinopathy, glaucoma, and macular degeneration. Our findings document the substantial role optometrists play in the delivery of eye care, whether they provide the care independently or in collaboration with an ophthalmologist. The levels of remuneration for optometrists are roughly one third to one half the annual rate for ophthalmologists. Staffing arrangements that use optometrists to the full extent of their professional training can provide significant cost savings. The cost-effectiveness of using the services of optometrists capable of delivering high-quality eye care can be demonstrated. Potential cost savings for staff model managed care organizations may accrue if the roles, functions, and availability of eye providers are adjusted.

Modelling removal mechanisms of Pb, Cu, Zn and Cd in acidic groundwater during the neutralization by ambient surface and ground waters

USGS Publications Warehouse

Paulson, Anthony J.; Balistrieri, Laurie S.

1999-01-01

Removal of Pb, Cu, Zn, and Cd during neutralization of acid rock drainage is examined using model simulations of field conditions and laboratory experiments involving mixing of natural drainage and surface waters or groundwaters. The simulations consider sorption onto hydrous Fe and Al oxides and particulate organic carbon, mineral precipitation, and organic and inorganic solution complexation of metals for two physical systems where newly formed oxides and particulate organic matter are either transported or retained along the chemical pathway. The calculations indicate that metal removal is a strong function of the physical system. Relative to direct discharge of ARD into streams, lower metal removals are observed where ARD enters streamwaters during the latter stages of neutralization by ambient groundwater after most of the Fe has precipitated and been retained in the soils. The mixing experiments, which represent the field simulations, also demonstrated the importance of dissolved metal to particle Fe ratios in controlling dissolved metal removal along the chemical pathway. Finally, model calculations indicate that hydrous Fe oxides and particulate organic carbon are more important than hydrous Al oxides in removing metals and that both inorganic and organic complexation must be considered when modeling metal removal from aquatic systems that are impacted by sulfide oxidation.

Implications of Information Theory for Computational Modeling of Schizophrenia.

PubMed

Silverstein, Steven M; Wibral, Michael; Phillips, William A

2017-10-01

Information theory provides a formal framework within which information processing and its disorders can be described. However, information theory has rarely been applied to modeling aspects of the cognitive neuroscience of schizophrenia. The goal of this article is to highlight the benefits of an approach based on information theory, including its recent extensions, for understanding several disrupted neural goal functions as well as related cognitive and symptomatic phenomena in schizophrenia. We begin by demonstrating that foundational concepts from information theory-such as Shannon information, entropy, data compression, block coding, and strategies to increase the signal-to-noise ratio-can be used to provide novel understandings of cognitive impairments in schizophrenia and metrics to evaluate their integrity. We then describe more recent developments in information theory, including the concepts of infomax, coherent infomax, and coding with synergy, to demonstrate how these can be used to develop computational models of schizophrenia-related failures in the tuning of sensory neurons, gain control, perceptual organization, thought organization, selective attention, context processing, predictive coding, and cognitive control. Throughout, we demonstrate how disordered mechanisms may explain both perceptual/cognitive changes and symptom emergence in schizophrenia. Finally, we demonstrate that there is consistency between some information-theoretic concepts and recent discoveries in neurobiology, especially involving the existence of distinct sites for the accumulation of driving input and contextual information prior to their interaction. This convergence can be used to guide future theory, experiment, and treatment development.

Implications of Information Theory for Computational Modeling of Schizophrenia

PubMed Central

Wibral, Michael; Phillips, William A.

2017-01-01

Information theory provides a formal framework within which information processing and its disorders can be described. However, information theory has rarely been applied to modeling aspects of the cognitive neuroscience of schizophrenia. The goal of this article is to highlight the benefits of an approach based on information theory, including its recent extensions, for understanding several disrupted neural goal functions as well as related cognitive and symptomatic phenomena in schizophrenia. We begin by demonstrating that foundational concepts from information theory—such as Shannon information, entropy, data compression, block coding, and strategies to increase the signal-to-noise ratio—can be used to provide novel understandings of cognitive impairments in schizophrenia and metrics to evaluate their integrity. We then describe more recent developments in information theory, including the concepts of infomax, coherent infomax, and coding with synergy, to demonstrate how these can be used to develop computational models of schizophrenia-related failures in the tuning of sensory neurons, gain control, perceptual organization, thought organization, selective attention, context processing, predictive coding, and cognitive control. Throughout, we demonstrate how disordered mechanisms may explain both perceptual/cognitive changes and symptom emergence in schizophrenia. Finally, we demonstrate that there is consistency between some information-theoretic concepts and recent discoveries in neurobiology, especially involving the existence of distinct sites for the accumulation of driving input and contextual information prior to their interaction. This convergence can be used to guide future theory, experiment, and treatment development. PMID:29601053

Defense Small Business Innovation Research Program (SBIR). Program Solicitation Number 89.1. FY-1989

DTIC Science & Technology

1989-01-06

scale testing, such as plasma-arc and oxyacetylene torch test are performed. However, correlations to relate ablation rate from these test data to...helicopter rotor. In phase II, the contractor should construct and demonstrate a working model. 36 A89-010 TITLE: Smooth, Erosion Resistant Coatings ...for Organic Matrix Composites OBJECTIVE: Erosion Resistant Coatings for Organic Matrix Composites for use in Compressor Section of Future Gas Turbine

Prospects for Classifying Complex Imagery Using a Self-Organizing Neural Network

DTIC Science & Technology

1989-01-11

complex imagery. In his original re- port, Fukushima demonstrated that this system could discriminate between simple alphabetical characters...on a VAX-8600 minicomputer. Wire frame models of three different vehicles were used to test the properties which Fukushima had demonstrated. The...Table No. Page 3-1 Parameters for Training on Three Input Images 14 3-2 Trained Results 17 vn 1. INTRODUCTION The Neocognitron of Fukushima [2

75 FR 42760 - Statement of Organization, Functions, and Delegations of Authority

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-22

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Teaching about Values and Goals: Applications of the Circumplex Model to Motivation, Well-Being, and Prosocial Behavior

ERIC Educational Resources Information Center

Kasser, Tim

2014-01-01

In this article, I review how people organize values and goals in their minds and I suggest teaching demonstrations, exercises, and assignments to help students learn this material. I pay special attention to circumplex models, which represent the extent of conflict or compatibility between values and goals, and to the well-researched distinction…

Quantifying the effect of organic aerosol aging and intermediate-volatility emissions on regional-scale aerosol pollution in China

PubMed Central

Zhao, Bin; Wang, Shuxiao; Donahue, Neil M.; Jathar, Shantanu H.; Huang, Xiaofeng; Wu, Wenjing; Hao, Jiming; Robinson, Allen L.

2016-01-01

Secondary organic aerosol (SOA) is one of the least understood constituents of fine particles; current widely-used models cannot predict its loadings or oxidation state. Recent laboratory experiments demonstrated the importance of several new processes, including aging of SOA from traditional precursors, aging of primary organic aerosol (POA), and photo-oxidation of intermediate volatility organic compounds (IVOCs). However, evaluating the effect of these processes in the real atmosphere is challenging. Most models used in previous studies are over-simplified and some key reaction trajectories are not captured, and model parameters are usually phenomenological and lack experimental constraints. Here we comprehensively assess the effect of organic aerosol (OA) aging and intermediate-volatility emissions on regional-scale OA pollution with a state-of-the-art model framework and experimentally constrained parameters. We find that OA aging and intermediate-volatility emissions together increase OA and SOA concentrations in Eastern China by about 40% and a factor of 10, respectively, thereby improving model-measurement agreement significantly. POA and IVOCs both constitute over 40% of OA concentrations, and IVOCs constitute over half of SOA concentrations; this differs significantly from previous apportionment of SOA sources. This study facilitates an improved estimate of aerosol-induced climate and health impacts, and implies a shift from current fine-particle control policies. PMID:27350423

A 3-D mathematical model to identify organ-specific risks in rats during thermal stress.

PubMed

Rakesh, Vineet; Stallings, Jonathan D; Helwig, Bryan G; Leon, Lisa R; Jackson, David A; Reifman, Jaques

2013-12-01

Early prediction of the adverse outcomes associated with heat stress is critical for effective management and mitigation of injury, which may sometimes lead to extreme undesirable clinical conditions, such as multiorgan dysfunction syndrome and death. Here, we developed a computational model to predict the spatiotemporal temperature distribution in a rat exposed to heat stress in an attempt to understand the correlation between heat load and differential organ dysfunction. The model includes a three-dimensional representation of the rat anatomy obtained from medical imaging and incorporates the key mechanisms of heat transfer during thermoregulation. We formulated a novel approach to estimate blood temperature by accounting for blood mixing from the different organs and to estimate the effects of the circadian rhythm in body temperature by considering day-night variations in metabolic heat generation and blood perfusion. We validated the model using in vivo core temperature measurements in control and heat-stressed rats and other published experimental data. The model predictions were within 1 SD of the measured data. The liver demonstrated the greatest susceptibility to heat stress, with the maximum temperature reaching 2°C higher than the measured core temperature and 95% of its volume exceeding the targeted experimental core temperature. Other organs also attained temperatures greater than the core temperature, illustrating the need to monitor multiple organs during heat stress. The model facilitates the identification of organ-specific risks during heat stress and has the potential to aid in the development of improved clinical strategies for thermal-injury prevention and management.

MATRIX-VBS (v1.0): Implementing an Evolving Organic Aerosol Volatility in an Aerosol Microphysics Model

NASA Technical Reports Server (NTRS)

Gao, Chloe Y.; Tsigaridis, Kostas; Bauer, Susanne E.

2017-01-01

The gas-particle partitioning and chemical aging of semi-volatile organic aerosol are presented in a newly developed box model scheme, where its effect on the growth, composition, and mixing state of particles is examined. The volatility-basis set (VBS) framework is implemented into the aerosol microphysical scheme MATRIX (Multiconfiguration Aerosol TRacker of mIXing state), which resolves mass and number aerosol concentrations and in multiple mixing-state classes. The new scheme, MATRIX-VBS, has the potential to significantly advance the representation of organic aerosols in Earth system models by improving upon the conventional representation as non-volatile particulate organic matter, often also with an assumed fixed size distribution. We present results from idealized cases representing Beijing, Mexico City, a Finnish forest, and a southeastern US forest, and investigate the evolution of mass concentrations and volatility distributions for organic species across the gas and particle phases, as well as assessing their mixing state among aerosol populations. Emitted semi-volatile primary organic aerosols evaporate almost completely in the intermediate-volatility range, while they remain in the particle phase in the low-volatility range. Their volatility distribution at any point in time depends on the applied emission factors, oxidation by OH radicals, and temperature. We also compare against parallel simulations with the original scheme, which represented only the particulate and non-volatile component of the organic aerosol, examining how differently the condensed-phase organic matter is distributed across the mixing states in the model. The results demonstrate the importance of representing organic aerosol as a semi-volatile aerosol, and explicitly calculating the partitioning of organic species between the gas and particulate phases.

The emergence of the Activity Reduces Conflict Associated Strain (ARCAS) model: a test of a conditional mediation model of workplace conflict and employee strain.

PubMed

Dijkstra, Maria T M; Beersma, Bianca; Cornelissen, Roosmarijn A W M

2012-07-01

To test and extend the emerging Activity Reduces Conflict-Associated Strain (ARCAS) model, we predicted that the relationship between task conflict and employee strain would be weakened to the extent that people experience high organization-based self-esteem (OBSE). A survey among Dutch employees demonstrated that, consistent with the model, the conflict-employee strain relationship was weaker the higher employees' OBSE and the more they engaged in active problem-solving conflict management. Our data also revealed that higher levels of OBSE were related to more problem-solving conflict management. Moreover, consistent with the ARCAS model, we could confirm a conditional mediation model in which organization-based self-esteem through its relationship with problem-solving conflict management weakened the relationship between task conflict and employee strain. Potential applications of the results are discussed.

Zebrafish Whole-Adult-Organism Chemogenomics for Large-Scale Predictive and Discovery Chemical Biology

PubMed Central

Lam, Siew Hong; Mathavan, Sinnakarupan; Tong, Yan; Li, Haixia; Karuturi, R. Krishna Murthy; Wu, Yilian; Vega, Vinsensius B.; Liu, Edison T.; Gong, Zhiyuan

2008-01-01

The ability to perform large-scale, expression-based chemogenomics on whole adult organisms, as in invertebrate models (worm and fly), is highly desirable for a vertebrate model but its feasibility and potential has not been demonstrated. We performed expression-based chemogenomics on the whole adult organism of a vertebrate model, the zebrafish, and demonstrated its potential for large-scale predictive and discovery chemical biology. Focusing on two classes of compounds with wide implications to human health, polycyclic (halogenated) aromatic hydrocarbons [P(H)AHs] and estrogenic compounds (ECs), we generated robust prediction models that can discriminate compounds of the same class from those of different classes in two large independent experiments. The robust expression signatures led to the identification of biomarkers for potent aryl hydrocarbon receptor (AHR) and estrogen receptor (ER) agonists, respectively, and were validated in multiple targeted tissues. Knowledge-based data mining of human homologs of zebrafish genes revealed highly conserved chemical-induced biological responses/effects, health risks, and novel biological insights associated with AHR and ER that could be inferred to humans. Thus, our study presents an effective, high-throughput strategy of capturing molecular snapshots of chemical-induced biological states of a whole adult vertebrate that provides information on biomarkers of effects, deregulated signaling pathways, and possible affected biological functions, perturbed physiological systems, and increased health risks. These findings place zebrafish in a strategic position to bridge the wide gap between cell-based and rodent models in chemogenomics research and applications, especially in preclinical drug discovery and toxicology. PMID:18618001

[Quality management in cardiovascular echography].

PubMed

Gullace, Giuseppe

2002-12-01

The quality management of an organization can be defined as the ability to identify, plan and implement programs of measure, analysis, verification and control that allow to monitor management, resources, activities, processes and output/outcome of the same organization, including the satisfaction of the customers. Whatever the model used, it is demonstrated that the management-quality system, either for professional quality or for organization, turns out to be effective even in the health organizations within and to any level of organizational-structural complexity. The present paper concerns the experience of the Italian Society of Cardiovascular Echography (SIEC) on quality certification, both as a scientific society compared to other health organizations and to cardiovascular echo laboratories, and the definition of minimum requirements for the accreditation of the same laboratories. The model most frequently used for quality management is represented by the ISO 9000: Vision 2000, that is a management model with specific reference to the organization and the customer satisfaction. The model applied to the health structure needs a rapid change in mentality that addresses the operators to define, share and achieve objectives to be brought on by means of an active collaboration, group activity and deep sense of belonging necessary to the attainment of expected objectives. When the model is applied by a scientific society, it is necessary to take into account the different structural and functional organization, the constitution and the operators differing on the point of view of origin, experiences, mentality, and roles. The ISO 9000: Vision 2000 model can be applied also to the cardiovascular echo laboratory which may be compared to a simple organization; for its corrected functioning, SIEC has defined minimal requirements for the accreditation, realization and modalities to carry out and manage quality. The quality system represents a new way of operating of an organization that enhances capability and performance of the operators, stimulates their creativity and facilitates the activities of all, to guarantee both the quality of the product and the satisfaction of operators and customers at the same time.

A versatile strategy for gene trapping and trap conversion in emerging model organisms.

PubMed

Kontarakis, Zacharias; Pavlopoulos, Anastasios; Kiupakis, Alexandros; Konstantinides, Nikolaos; Douris, Vassilis; Averof, Michalis

2011-06-01

Genetic model organisms such as Drosophila, C. elegans and the mouse provide formidable tools for studying mechanisms of development, physiology and behaviour. Established models alone, however, allow us to survey only a tiny fraction of the morphological and functional diversity present in the animal kingdom. Here, we present iTRAC, a versatile gene-trapping approach that combines the implementation of unbiased genetic screens with the generation of sophisticated genetic tools both in established and emerging model organisms. The approach utilises an exon-trapping transposon vector that carries an integrase docking site, allowing the targeted integration of new constructs into trapped loci. We provide proof of principle for iTRAC in the emerging model crustacean Parhyale hawaiensis: we generate traps that allow specific developmental and physiological processes to be visualised in unparalleled detail, we show that trapped genes can be easily cloned from an unsequenced genome, and we demonstrate targeting of new constructs into a trapped locus. Using this approach, gene traps can serve as platforms for generating diverse reporters, drivers for tissue-specific expression, gene knockdown and other genetic tools not yet imagined.

The growth, characterization, and application of highly ordered small molecule semiconducting thin films

NASA Astrophysics Data System (ADS)

Lunt, Richard Royal, III

Organic semiconductors have gained tremendous attention recently as their use in field effect transistors, sensors, solar cells, lasers, and organic light emitting diodes have been demonstrated, offering the potential for low-cost alternatives. Since renewable energy remains one the greatest challenges of the 21st century, the possibility for low-cost and flexible organic photovoltaics is particularly exciting. In the first part of this thesis, we demonstrate a route to the controlled growth of oriented crystalline films through organic vapor-phase deposition (OVPD), in conjunction with organic-inorganic, and organic-organic quasi-epitaxy. This method for producing highly ordered crystalline thin-film heterostructures combines the control of film growth with the electronic properties expected to approach that of organic single crystals, making them potentially useful for high efficiency organic thin-film devices and solar cells. We further demonstrate OVPD as a method for the deposition of large-scale organic electronics with low material waste, a key ability in fulfilling the promise of low-cost organic devices. The second part of this thesis is focused on understanding factors that govern energy (i.e. exciton) transport. The two single most important and fundamental properties of organic semiconductors are the transport of charge and energy. While charge mobility has been extensively studied and convincingly linked to the degree of crystalline order and orientation, the principles governing energy transport, i.e. exciton migration, in this class of materials and the subsequent connection to crystalline properties still remain ambiguous. Therefore, we aim to understand key aspects governing exciton motion in organic materials to better engineer materials, film morphologies, and film architectures for organic electronics with improved performance. To this end, we have developed a new method for measuring exciton diffusion and characterize a range of archetypal organic compounds. We then derive a simple theoretical model that provides insight into the control of exciton migration in organic systems through changes in both crystal orientation (anisotropy) and degree of crystalline order, which is crucial for the management of energy transport in a wide range of important organic electronic devices.

An integrative model linking feedback environment and organizational citizenship behavior.

PubMed

Peng, Jei-Chen; Chiu, Su-Fen

2010-01-01

Past empirical evidence has suggested that a positive supervisor feedback environment may enhance employees' organizational citizenship behavior (OCB). In this study, we aim to extend previous research by proposing and testing an integrative model that examines the mediating processes underlying the relationship between supervisor feedback environment and employee OCB. Data were collected from 259 subordinate-supervisor dyads across a variety of organizations in Taiwan. We used structural equation modeling to test our hypotheses. The results demonstrated that supervisor feedback environment influenced employees' OCB indirectly through (1) both positive affective-cognition and positive attitude (i.e., person-organization fit and organizational commitment), and (2) both negative affective-cognition and negative attitude (i.e., role stressors and job burnout). Theoretical and practical implications are discussed.

Hybrid Nanowire Ion-to-Electron Transducers for Integrated Bioelectronic Circuitry.

PubMed

Carrad, D J; Mostert, A B; Ullah, A R; Burke, A M; Joyce, H J; Tan, H H; Jagadish, C; Krogstrup, P; Nygård, J; Meredith, P; Micolich, A P

2017-02-08

A key task in the emerging field of bioelectronics is the transduction between ionic/protonic and electronic signals at high fidelity. This is a considerable challenge since the two carrier types exhibit intrinsically different physics and are best supported by very different materials types-electronic signals in inorganic semiconductors and ionic/protonic signals in organic or bio-organic polymers, gels, or electrolytes. Here we demonstrate a new class of organic-inorganic transducing interface featuring semiconducting nanowires electrostatically gated using a solid proton-transporting hygroscopic polymer. This model platform allows us to study the basic transducing mechanisms as well as deliver high fidelity signal conversion by tapping into and drawing together the best candidates from traditionally disparate realms of electronic materials research. By combining complementary n- and p-type transducers we demonstrate functional logic with significant potential for scaling toward high-density integrated bioelectronic circuitry.

A recursive vesicle-based model protocell with a primitive model cell cycle

NASA Astrophysics Data System (ADS)

Kurihara, Kensuke; Okura, Yusaku; Matsuo, Muneyuki; Toyota, Taro; Suzuki, Kentaro; Sugawara, Tadashi

2015-09-01

Self-organized lipid structures (protocells) have been proposed as an intermediate between nonliving material and cellular life. Synthetic production of model protocells can demonstrate the potential processes by which living cells first arose. While we have previously described a giant vesicle (GV)-based model protocell in which amplification of DNA was linked to self-reproduction, the ability of a protocell to recursively self-proliferate for multiple generations has not been demonstrated. Here we show that newborn daughter GVs can be restored to the status of their parental GVs by pH-induced vesicular fusion of daughter GVs with conveyer GVs filled with depleted substrates. We describe a primitive model cell cycle comprising four discrete phases (ingestion, replication, maturity and division), each of which is selectively activated by a specific external stimulus. The production of recursive self-proliferating model protocells represents a step towards eventual production of model protocells that are able to mimic evolution.

Organic Pollutant Penetration through Fruit Polyester Skin: A Modified Three-compartment Diffusion Model

NASA Astrophysics Data System (ADS)

Li, Yungui; Li, Qingqing; Chen, Baoliang

2016-03-01

The surface of plants is covered by a continuous but heterogeneous cuticular membrane (CM). Serving as the first protective barrier, the uptake and transport behavior of organic pollutants at this interface continue to engage the research efforts of environmental chemist. To date, the contributions of cuticular components as a defense against the organic pollutants penetration remain unresolved. In this study, the unsteady-state penetration characteristics of phenanthrene (PHE) through isolated fruit CM was investigated. PHE penetration was differentiated by three cuticular compartments: epicuticular waxes (EW), cuticle proper (CP) and cuticular layer (CL). The driving force for PHE penetration was ascribed to the sharp concentration gradient built up endogenously by cuticular compartments with different lipophilic affinities. A modified penetration model was established and verified in terms of its general suitability for the hydrophobic chemicals and CMs of various plant species (apple, tomato and potato). The new three-compartment model demonstrates much higher accuracy in characterizing the uptake and transport behavior of semivolatile chemicals with fewer limitations in terms of environmental conditions and complexity (e.g., coexisting contaminants and temperature). This model could contribute to a more comprehensive understanding on the role of polymeric lipids in the organic pollutant sorption and transport into plants.

Organic Pollutant Penetration through Fruit Polyester Skin: A Modified Three-compartment Diffusion Model.

PubMed

Li, Yungui; Li, Qingqing; Chen, Baoliang

2016-03-24

The surface of plants is covered by a continuous but heterogeneous cuticular membrane (CM). Serving as the first protective barrier, the uptake and transport behavior of organic pollutants at this interface continue to engage the research efforts of environmental chemist. To date, the contributions of cuticular components as a defense against the organic pollutants penetration remain unresolved. In this study, the unsteady-state penetration characteristics of phenanthrene (PHE) through isolated fruit CM was investigated. PHE penetration was differentiated by three cuticular compartments: epicuticular waxes (EW), cuticle proper (CP) and cuticular layer (CL). The driving force for PHE penetration was ascribed to the sharp concentration gradient built up endogenously by cuticular compartments with different lipophilic affinities. A modified penetration model was established and verified in terms of its general suitability for the hydrophobic chemicals and CMs of various plant species (apple, tomato and potato). The new three-compartment model demonstrates much higher accuracy in characterizing the uptake and transport behavior of semivolatile chemicals with fewer limitations in terms of environmental conditions and complexity (e.g., coexisting contaminants and temperature). This model could contribute to a more comprehensive understanding on the role of polymeric lipids in the organic pollutant sorption and transport into plants.

Structural determinants for membrane association and dynamic organization of the hepatitis C virus NS3-4A complex

PubMed Central

Brass, Volker; Berke, Jan Martin; Montserret, Roland; Blum, Hubert E.; Penin, François; Moradpour, Darius

2008-01-01

Hepatitis C virus (HCV) NS3-4A is a membrane-associated multifunctional protein harboring serine protease and RNA helicase activities. It is an essential component of the HCV replication complex and a prime target for antiviral intervention. Here, we show that membrane association and structural organization of HCV NS3-4A are ensured in a cooperative manner by two membrane-binding determinants. We demonstrate that the N-terminal 21 amino acids of NS4A form a transmembrane α-helix that may be involved in intramembrane protein–protein interactions important for the assembly of a functional replication complex. In addition, we demonstrate that amphipathic helix α0, formed by NS3 residues 12–23, serves as a second essential determinant for membrane association of NS3-4A, allowing proper positioning of the serine protease active site on the membrane. These results allowed us to propose a dynamic model for the membrane association, processing, and structural organization of NS3-4A on the membrane. This model has implications for the functional architecture of the HCV replication complex, proteolytic targeting of host factors, and drug design. PMID:18799730

BETR Global - A geographically explicit global-scale multimedia contaminant fate model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Macleod, M.; Waldow, H. von; Tay, P.

2011-04-01

We present two new software implementations of the BETR Global multimedia contaminant fate model. The model uses steady-state or non-steady-state mass-balance calculations to describe the fate and transport of persistent organic pollutants using a desktop computer. The global environment is described using a database of long-term average monthly conditions on a 15{sup o} x 15{sup o} grid. We demonstrate BETR Global by modeling the global sources, transport, and removal of decamethylcyclopentasiloxane (D5).

Integrated approaches to the application of advanced modeling technology in process development and optimization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allgor, R.J.; Feehery, W.F.; Tolsma, J.E.

The batch process development problem serves as good candidate to guide the development of process modeling environments. It demonstrates that very robust numerical techniques are required within an environment that can collect, organize, and maintain the data and models required to address the batch process development problem. This paper focuses on improving the robustness and efficiency of the numerical algorithms required in such a modeling environment through the development of hybrid numerical and symbolic strategies.

Modeling microbial survival in buildup biofilm for complex medical devices

PubMed Central

2009-01-01

Background Flexible endoscopes undergo repeated rounds of patient-use and reprocessing. Some evidence indicates that there is an accumulation or build-up of organic material that occurs over time in endoscope channels. This "buildup biofilm" (BBF) develops as a result of cyclical exposure to wet and dry phases during usage and reprocessing. This study investigated whether the BBF matrix represents a greater challenge to disinfectant efficacy and microbial eradication than traditional biofilm (TBF), which forms when a surface is constantly bathed in fluid. Methods Using the MBEC (Minimum Biofilm Eradication Concentration) system, a unique modelling approach was developed to evaluate microbial survival in BBF formed by repetitive cycles of drying, disinfectant exposure and re-exposure to the test organism. This model mimics the cumulative effect of the reprocessing protocol on flexible endoscopes. Glutaraldehyde (GLUT) and accelerated hydrogen peroxide (AHP) were evaluated to assess the killing of microbes in TBF and BBF. Results The data showed that the combination of an organic matrix and aldehyde disinfection quickly produced a protective BBF that facilitated high levels of organism survival. In cross-linked BBF formed under high nutrient conditions the maximum colony forming units (CFU) reached ~6 Log10 CFU/peg. However, if an oxidizing agent was used for disinfection and if organic levels were kept low, organism survival did not occur. A key finding was that once established, the microbial load of BBF formed by GLUT exposure had a faster rate of accumulation than in TBF. The rate of biofilm survival post high-level disinfection (HLD) determined by the maximum Log10CFU/initial Log10CFU for E. faecalis and P. aeruginosa in BBF was 10 and 8.6 respectively; significantly different compared to a survival rate in TBF of ~2 for each organism. Data from indirect outgrowth testing demonstrated for the first time that there is organism survival in the matrix. Both TBF and BBF had surviving organisms when GLUT was used. For AHP survival was seen less frequently in BBF than in TBF. Conclusion This BBF model demonstrated for the first time that survival of a wide range of microorganisms does occur in BBF, with significantly more rapid outgrowth compared to TBF. This is most pronounced when GLUT is used compared to AHP. The data supports the need for meticulous cleaning of reprocessed endoscopes since the presence of organic material and microorganisms prevents effective disinfection when GLUT and AHP are used. However, cross-linking agents like GLUT are not as effective when there is BBF. The data from the MBEC model of BBF suggest that for flexible endoscopes that are repeatedly used and reprocessed, the assurance of effective high-level disinfection may decrease if BBF develops within the channels. PMID:19426471

Habituation in non-neural organisms: evidence from slime moulds.

PubMed

Boisseau, Romain P; Vogel, David; Dussutour, Audrey

2016-04-27

Learning, defined as a change in behaviour evoked by experience, has hitherto been investigated almost exclusively in multicellular neural organisms. Evidence for learning in non-neural multicellular organisms is scant, and only a few unequivocal reports of learning have been described in single-celled organisms. Here we demonstrate habituation, an unmistakable form of learning, in the non-neural organism Physarum polycephalum In our experiment, using chemotaxis as the behavioural output and quinine or caffeine as the stimulus, we showed that P. polycephalum learnt to ignore quinine or caffeine when the stimuli were repeated, but responded again when the stimulus was withheld for a certain time. Our results meet the principle criteria that have been used to demonstrate habituation: responsiveness decline and spontaneous recovery. To distinguish habituation from sensory adaptation or motor fatigue, we also show stimulus specificity. Our results point to the diversity of organisms lacking neurons, which likely display a hitherto unrecognized capacity for learning, and suggest that slime moulds may be an ideal model system in which to investigate fundamental mechanisms underlying learning processes. Besides, documenting learning in non-neural organisms such as slime moulds is centrally important to a comprehensive, phylogenetic understanding of when and where in the tree of life the earliest manifestations of learning evolved. © 2016 The Author(s).

Habituation in non-neural organisms: evidence from slime moulds

PubMed Central

Boisseau, Romain P.; Vogel, David; Dussutour, Audrey

2016-01-01

Learning, defined as a change in behaviour evoked by experience, has hitherto been investigated almost exclusively in multicellular neural organisms. Evidence for learning in non-neural multicellular organisms is scant, and only a few unequivocal reports of learning have been described in single-celled organisms. Here we demonstrate habituation, an unmistakable form of learning, in the non-neural organism Physarum polycephalum. In our experiment, using chemotaxis as the behavioural output and quinine or caffeine as the stimulus, we showed that P. polycephalum learnt to ignore quinine or caffeine when the stimuli were repeated, but responded again when the stimulus was withheld for a certain time. Our results meet the principle criteria that have been used to demonstrate habituation: responsiveness decline and spontaneous recovery. To distinguish habituation from sensory adaptation or motor fatigue, we also show stimulus specificity. Our results point to the diversity of organisms lacking neurons, which likely display a hitherto unrecognized capacity for learning, and suggest that slime moulds may be an ideal model system in which to investigate fundamental mechanisms underlying learning processes. Besides, documenting learning in non-neural organisms such as slime moulds is centrally important to a comprehensive, phylogenetic understanding of when and where in the tree of life the earliest manifestations of learning evolved. PMID:27122563

Synchrotron based mass spectrometry to investigate the molecular properties of mineral-organic associations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Suet Yi; Kleber, Markus; Takahashi, Lynelle K.

2013-04-01

Soil organic matter (OM) is important because its decay drives life processes in the biosphere. Analysis of organic compounds in geological systems is difficult because of their intimate association with mineral surfaces. To date there is no procedure capable of quantitatively separating organic from mineral phases without creating artifacts or mass loss. Therefore, analytical techniques that can (a) generate information about both organic and mineral phases simultaneously and (b) allow the examination of predetermined high-interest regions of the sample as opposed to conventional bulk analytical techniques are valuable. Laser Desorption Synchrotron Postionization (synchrotron-LDPI) mass spectrometry is introduced as a novelmore » analytical tool to characterize the molecular properties of organic compounds in mineral-organic samples from terrestrial systems, and it is demonstrated that when combined with Secondary Ion Mass Spectrometry (SIMS), can provide complementary information on mineral composition. Mass spectrometry along a decomposition gradient in density fractions, verifies the consistency of our results with bulk analytical techniques. We further demonstrate that by changing laser and photoionization energies, variations in molecular stability of organic compounds associated with mineral surfaces can be determined. The combination of synchrotron-LDPI and SIMS shows that the energetic conditions involved in desorption and ionization of organic matter may be a greater determinant of mass spectral signatures than the inherent molecular structure of the organic compounds investigated. The latter has implications for molecular models of natural organic matter that are based on mass spectrometric information.« less

Self-Organizing Hidden Markov Model Map (SOHMMM): Biological Sequence Clustering and Cluster Visualization.

PubMed

Ferles, Christos; Beaufort, William-Scott; Ferle, Vanessa

2017-01-01

The present study devises mapping methodologies and projection techniques that visualize and demonstrate biological sequence data clustering results. The Sequence Data Density Display (SDDD) and Sequence Likelihood Projection (SLP) visualizations represent the input symbolical sequences in a lower-dimensional space in such a way that the clusters and relations of data elements are depicted graphically. Both operate in combination/synergy with the Self-Organizing Hidden Markov Model Map (SOHMMM). The resulting unified framework is in position to analyze automatically and directly raw sequence data. This analysis is carried out with little, or even complete absence of, prior information/domain knowledge.

Contraceptive Behavior and Adolescent Lifestyles: A Structural Modeling Approach.

ERIC Educational Resources Information Center

Fortenberry, J. Dennis; And Others

1997-01-01

Relations of contraceptive behavior, problem behaviors, and health-protective behaviors were examined in an ethnically and socioeconomically diverse sample of sexually active adolescents. Findings demonstrate substantial organization among adolescent health and problem behaviors and suggest that contraceptive behavior should be conceptualized…

77 FR 15566 - Private Transfer Fees

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-16

... expense of successive homebuyers. Nothing in the Freehold model demonstrates that any benefit is ever...' associations, condominiums, cooperatives, and similar organizations that use the fees to directly benefit the... benefit homeowners or the properties involved, and, therefore, could impair the safety and soundness of...

Microphysical explanation of the RH-dependent water affinity of biogenic organic aerosol and its importance for climate

DOE PAGES

Rastak, N.; Pajunoja, A.; Acosta Navarro, J. C.; ...

2017-04-28

A large fraction of atmospheric organic aerosol (OA) originates from natural emissions that are oxidized in the atmosphere to form secondary organic aerosol (SOA). Isoprene (IP) and monoterpenes (MT) are the most important precursors of SOA originating from forests. The climate impacts from OA are currently estimated through parameterizations of water uptake that drastically simplify the complexity of OA. We combine laboratory experiments, thermodynamic modeling, field observations, and climate modeling to (1) explain the molecular mechanisms behind RH-dependent SOA water-uptake with solubility and phase separation; (2) show that laboratory data on IP- and MT-SOA hygroscopicity are representative of ambient datamore » with corresponding OA source profiles; and (3) demonstrate the sensitivity of the modeled aerosol climate effect to assumed OA water affinity. We conclude that the commonly used single-parameter hygroscopicity framework can introduce significant error when quantifying the climate effects of organic aerosol. The results highlight the need for better constraints on the overall global OA mass loadings and its molecular composition, including currently underexplored anthropogenic and marine OA sources.« less

Microphysical explanation of the RH-dependent water affinity of biogenic organic aerosol and its importance for climate

NASA Astrophysics Data System (ADS)

Rastak, N.; Pajunoja, A.; Acosta Navarro, J. C.; Ma, J.; Song, M.; Partridge, D. G.; Kirkevâg, A.; Leong, Y.; Hu, W. W.; Taylor, N. F.; Lambe, A.; Cerully, K.; Bougiatioti, A.; Liu, P.; Krejci, R.; Petäjä, T.; Percival, C.; Davidovits, P.; Worsnop, D. R.; Ekman, A. M. L.; Nenes, A.; Martin, S.; Jimenez, J. L.; Collins, D. R.; Topping, D. O.; Bertram, A. K.; Zuend, A.; Virtanen, A.; Riipinen, I.

2017-05-01

A large fraction of atmospheric organic aerosol (OA) originates from natural emissions that are oxidized in the atmosphere to form secondary organic aerosol (SOA). Isoprene (IP) and monoterpenes (MT) are the most important precursors of SOA originating from forests. The climate impacts from OA are currently estimated through parameterizations of water uptake that drastically simplify the complexity of OA. We combine laboratory experiments, thermodynamic modeling, field observations, and climate modeling to (1) explain the molecular mechanisms behind RH-dependent SOA water-uptake with solubility and phase separation; (2) show that laboratory data on IP- and MT-SOA hygroscopicity are representative of ambient data with corresponding OA source profiles; and (3) demonstrate the sensitivity of the modeled aerosol climate effect to assumed OA water affinity. We conclude that the commonly used single-parameter hygroscopicity framework can introduce significant error when quantifying the climate effects of organic aerosol. The results highlight the need for better constraints on the overall global OA mass loadings and its molecular composition, including currently underexplored anthropogenic and marine OA sources.

Microphysical explanation of the RH-dependent water affinity of biogenic organic aerosol and its importance for climate.

PubMed

Rastak, N; Pajunoja, A; Acosta Navarro, J C; Ma, J; Song, M; Partridge, D G; Kirkevåg, A; Leong, Y; Hu, W W; Taylor, N F; Lambe, A; Cerully, K; Bougiatioti, A; Liu, P; Krejci, R; Petäjä, T; Percival, C; Davidovits, P; Worsnop, D R; Ekman, A M L; Nenes, A; Martin, S; Jimenez, J L; Collins, D R; Topping, D O; Bertram, A K; Zuend, A; Virtanen, A; Riipinen, I

2017-05-28

A large fraction of atmospheric organic aerosol (OA) originates from natural emissions that are oxidized in the atmosphere to form secondary organic aerosol (SOA). Isoprene (IP) and monoterpenes (MT) are the most important precursors of SOA originating from forests. The climate impacts from OA are currently estimated through parameterizations of water uptake that drastically simplify the complexity of OA. We combine laboratory experiments, thermodynamic modeling, field observations, and climate modeling to (1) explain the molecular mechanisms behind RH-dependent SOA water-uptake with solubility and phase separation; (2) show that laboratory data on IP- and MT-SOA hygroscopicity are representative of ambient data with corresponding OA source profiles; and (3) demonstrate the sensitivity of the modeled aerosol climate effect to assumed OA water affinity. We conclude that the commonly used single-parameter hygroscopicity framework can introduce significant error when quantifying the climate effects of organic aerosol. The results highlight the need for better constraints on the overall global OA mass loadings and its molecular composition, including currently underexplored anthropogenic and marine OA sources.

Microphysical explanation of the RH‐dependent water affinity of biogenic organic aerosol and its importance for climate

PubMed Central

Rastak, N.; Pajunoja, A.; Acosta Navarro, J. C.; Ma, J.; Song, M.; Partridge, D. G.; Kirkevåg, A.; Leong, Y.; Hu, W. W.; Taylor, N. F.; Lambe, A.; Cerully, K.; Bougiatioti, A.; Liu, P.; Krejci, R.; Petäjä, T.; Percival, C.; Davidovits, P.; Worsnop, D. R.; Ekman, A. M. L.; Nenes, A.; Martin, S.; Jimenez, J. L.; Collins, D. R.; Topping, D.O.; Bertram, A. K.; Zuend, A.; Virtanen, A.

2017-01-01

Abstract A large fraction of atmospheric organic aerosol (OA) originates from natural emissions that are oxidized in the atmosphere to form secondary organic aerosol (SOA). Isoprene (IP) and monoterpenes (MT) are the most important precursors of SOA originating from forests. The climate impacts from OA are currently estimated through parameterizations of water uptake that drastically simplify the complexity of OA. We combine laboratory experiments, thermodynamic modeling, field observations, and climate modeling to (1) explain the molecular mechanisms behind RH‐dependent SOA water‐uptake with solubility and phase separation; (2) show that laboratory data on IP‐ and MT‐SOA hygroscopicity are representative of ambient data with corresponding OA source profiles; and (3) demonstrate the sensitivity of the modeled aerosol climate effect to assumed OA water affinity. We conclude that the commonly used single‐parameter hygroscopicity framework can introduce significant error when quantifying the climate effects of organic aerosol. The results highlight the need for better constraints on the overall global OA mass loadings and its molecular composition, including currently underexplored anthropogenic and marine OA sources. PMID:28781391

Microphysical explanation of the RH-dependent water affinity of biogenic organic aerosol and its importance for climate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rastak, N.; Pajunoja, A.; Acosta Navarro, J. C.

A large fraction of atmospheric organic aerosol (OA) originates from natural emissions that are oxidized in the atmosphere to form secondary organic aerosol (SOA). Isoprene (IP) and monoterpenes (MT) are the most important precursors of SOA originating from forests. The climate impacts from OA are currently estimated through parameterizations of water uptake that drastically simplify the complexity of OA. We combine laboratory experiments, thermodynamic modeling, field observations, and climate modeling to (1) explain the molecular mechanisms behind RH-dependent SOA water-uptake with solubility and phase separation; (2) show that laboratory data on IP- and MT-SOA hygroscopicity are representative of ambient datamore » with corresponding OA source profiles; and (3) demonstrate the sensitivity of the modeled aerosol climate effect to assumed OA water affinity. We conclude that the commonly used single-parameter hygroscopicity framework can introduce significant error when quantifying the climate effects of organic aerosol. The results highlight the need for better constraints on the overall global OA mass loadings and its molecular composition, including currently underexplored anthropogenic and marine OA sources.« less

Gender differences in organ density in a rat simulated microgravity model

NASA Astrophysics Data System (ADS)

Pettis, Christopher Ryan; Witten, Mark Lee

2004-01-01

Research investigating the physiological effects of microgravity on the human body has demonstrated a shift of body fluids in actual spaceflight and in simulated Earth-based microgravity models in both males and females, possibly causing many deleterious physiological effects. Twenty-five anatomically normal female (NF) and 20 ovariectomized (OE) Fischer 344 rats were randomly selected to be in an experimental ( 1 h of 45° head-down tilt, 45HDT) or control ( 1 h of prone position) group. At the end of the hour experimental period, the density of the brain, lungs, heart, liver, and left and right kidneys were measured using spiral computed tomography (SCT) while the rats remained in their experimental positions. A sub-group of OE rats ( N=6) was administered estrogen replacement therapy on a daily basis ( 5 μg/kg body weight, s.c.) for 4 days and then underwent 1 h of 45HDT and SCT analysis at one day, 2 days, and 5 days to determine if estrogen replacement therapy would alter organ densities. Our data demonstrate that 1 h of 45HDT produced significant increases ( p<0.05) in the organ densities of the brain, liver, left kidney, and lung of the OE female group compared to their prone controls. However, only the brain density was significantly increased in the NF group. Estrogen replacement therapy caused a significant decrease in brain organ density at the 5 day time point compared to the 24 h time point. We conclude that estrogen plays a role in fluid distribution in a rat 45HDT model.

A novel mouse model of tuberous sclerosis complex (TSC): eye-specific Tsc1-ablation disrupts visual-pathway development

PubMed Central

Jones, Iwan; Hägglund, Anna-Carin; Törnqvist, Gunilla; Nord, Christoffer; Ahlgren, Ulf; Carlsson, Leif

2015-01-01

ABSTRACT Tuberous sclerosis complex (TSC) is an autosomal dominant syndrome that is best characterised by neurodevelopmental deficits and the presence of benign tumours (called hamartomas) in affected organs. This multi-organ disorder results from inactivating point mutations in either the TSC1 or the TSC2 genes and consequent activation of the canonical mammalian target of rapamycin complex 1 signalling (mTORC1) pathway. Because lesions to the eye are central to TSC diagnosis, we report here the generation and characterisation of the first eye-specific TSC mouse model. We demonstrate that conditional ablation of Tsc1 in eye-committed progenitor cells leads to the accelerated differentiation and subsequent ectopic radial migration of retinal ganglion cells. This results in an increase in retinal ganglion cell apoptosis and consequent regionalised axonal loss within the optic nerve and topographical changes to the contra- and ipsilateral input within the dorsal lateral geniculate nucleus. Eyes from adult mice exhibit aberrant retinal architecture and display all the classic neuropathological hallmarks of TSC, including an increase in organ and cell size, ring heterotopias, hamartomas with retinal detachment, and lamination defects. Our results provide the first major insight into the molecular etiology of TSC within the developing eye and demonstrate a pivotal role for Tsc1 in regulating various aspects of visual-pathway development. Our novel mouse model therefore provides a valuable resource for future studies concerning the molecular mechanisms underlying TSC and also as a platform to evaluate new therapeutic approaches for the treatment of this multi-organ disorder. PMID:26449264

A novel mouse model of tuberous sclerosis complex (TSC): eye-specific Tsc1-ablation disrupts visual-pathway development.

PubMed

Jones, Iwan; Hägglund, Anna-Carin; Törnqvist, Gunilla; Nord, Christoffer; Ahlgren, Ulf; Carlsson, Leif

2015-12-01

Tuberous sclerosis complex (TSC) is an autosomal dominant syndrome that is best characterised by neurodevelopmental deficits and the presence of benign tumours (called hamartomas) in affected organs. This multi-organ disorder results from inactivating point mutations in either the TSC1 or the TSC2 genes and consequent activation of the canonical mammalian target of rapamycin complex 1 signalling (mTORC1) pathway. Because lesions to the eye are central to TSC diagnosis, we report here the generation and characterisation of the first eye-specific TSC mouse model. We demonstrate that conditional ablation of Tsc1 in eye-committed progenitor cells leads to the accelerated differentiation and subsequent ectopic radial migration of retinal ganglion cells. This results in an increase in retinal ganglion cell apoptosis and consequent regionalised axonal loss within the optic nerve and topographical changes to the contra- and ipsilateral input within the dorsal lateral geniculate nucleus. Eyes from adult mice exhibit aberrant retinal architecture and display all the classic neuropathological hallmarks of TSC, including an increase in organ and cell size, ring heterotopias, hamartomas with retinal detachment, and lamination defects. Our results provide the first major insight into the molecular etiology of TSC within the developing eye and demonstrate a pivotal role for Tsc1 in regulating various aspects of visual-pathway development. Our novel mouse model therefore provides a valuable resource for future studies concerning the molecular mechanisms underlying TSC and also as a platform to evaluate new therapeutic approaches for the treatment of this multi-organ disorder. © 2015. Published by The Company of Biologists Ltd.

Processes of social learning in the tool use of chimpanzees (Pan troglodytes) and human children (Homo sapiens).

PubMed

Nagell, K; Olguin, R S; Tomasello, M

1993-06-01

Common chimpanzees (Pan troglodytes) and 2-year-old human children (Homo sapiens) were presented with a rakelike tool and a desirable but out-of-reach object. One group of subjects observed a human demonstrator use the tool in one way, and another group observed a demonstrator use the tool in another way. Children in both cases did what the model did. Chimpanzee subjects, however, behaved identically in the 2 model conditions. Both groups performed better than subjects who saw no demonstration. This pattern of results suggest that the chimpanzees were paying attention to the general functional relations in the task and to the results obtained by the demonstrator but not to the actual methods of tool use demonstrated. Human children were focused on the demonstrator's actual methods of tool use (her behavior). The different social learning processes used by the 2 species have implications for their different forms of social organization.

Application of retention modelling to the simulation of separation of organic anions in suppressed ion chromatography.

PubMed

Zakaria, Philip; Dicinoski, Greg W; Ng, Boon Khing; Shellie, Robert A; Hanna-Brown, Melissa; Haddad, Paul R

2009-09-18

The ion-exchange separation of organic anions of varying molecular mass has been demonstrated using ion chromatography with isocratic, gradient and multi-step eluent profiles on commercially available columns with UV detection. A retention model derived previously for inorganic ions and based solely on electrostatic interactions between the analytes and the stationary phase was applied. This model was found to accurately describe the observed elution of all the anions under isocratic, gradient and multi-step eluent conditions. Hydrophobic interactions, although likely to be present to varying degrees, did not limit the applicability of the ion-exchange retention model. Various instrumental configurations were investigated to overcome problems associated with the use of organic modifiers in the eluent which caused compatibility issues with the electrolytically derived, and subsequently suppressed, eluent. The preferred configuration allowed the organic modifier stream to bypass the eluent generator, followed by subsequent mixing before entering the injection valve and column. Accurate elution prediction was achieved even when using 5-step eluent profiles with errors in retention time generally being less than 1% relative standard deviation (RSD) and all being less than 5% RSD. Peak widths for linear gradient separations were also modelled and showed good agreement with experimentally determined values.

Open-target sparse sensing of biological agents using DNA microarray

PubMed Central

2011-01-01

Background Current biosensors are designed to target and react to specific nucleic acid sequences or structural epitopes. These 'target-specific' platforms require creation of new physical capture reagents when new organisms are targeted. An 'open-target' approach to DNA microarray biosensing is proposed and substantiated using laboratory generated data. The microarray consisted of 12,900 25 bp oligonucleotide capture probes derived from a statistical model trained on randomly selected genomic segments of pathogenic prokaryotic organisms. Open-target detection of organisms was accomplished using a reference library of hybridization patterns for three test organisms whose DNA sequences were not included in the design of the microarray probes. Results A multivariate mathematical model based on the partial least squares regression (PLSR) was developed to detect the presence of three test organisms in mixed samples. When all 12,900 probes were used, the model correctly detected the signature of three test organisms in all mixed samples (mean(R2)) = 0.76, CI = 0.95), with a 6% false positive rate. A sampling algorithm was then developed to sparsely sample the probe space for a minimal number of probes required to capture the hybridization imprints of the test organisms. The PLSR detection model was capable of correctly identifying the presence of the three test organisms in all mixed samples using only 47 probes (mean(R2)) = 0.77, CI = 0.95) with nearly 100% specificity. Conclusions We conceived an 'open-target' approach to biosensing, and hypothesized that a relatively small, non-specifically designed, DNA microarray is capable of identifying the presence of multiple organisms in mixed samples. Coupled with a mathematical model applied to laboratory generated data, and sparse sampling of capture probes, the prototype microarray platform was able to capture the signature of each organism in all mixed samples with high sensitivity and specificity. It was demonstrated that this new approach to biosensing closely follows the principles of sparse sensing. PMID:21801424

Interorgan Communication Pathways in Physiology: Focus on Drosophila

PubMed Central

Droujinine, Ilia A.; Perrimon, Norbert

2017-01-01

Studies in mammals and Drosophila have demonstrated the existence and significance of secreted factors involved in communication between distal organs. In this review, primarily focusing on Drosophila, we examine the known interorgan communication factors and their functions, physiological inducers, and integration in regulating physiology. Moreover, we describe how organ-sensing screens in Drosophila can systematically identify novel conserved interorgan communication factors. Finally, we discuss how interorgan communication enabled and evolved as a result of specialization of organs. Together, we anticipate that future studies will establish a model for metazoan interorgan communication network (ICN) and how it is deregulated in disease. PMID:27732790

Interorgan Communication Pathways in Physiology: Focus on Drosophila.

PubMed

Droujinine, Ilia A; Perrimon, Norbert

2016-11-23

Studies in mammals and Drosophila have demonstrated the existence and significance of secreted factors involved in communication between distal organs. In this review, primarily focusing on Drosophila, we examine the known interorgan communication factors and their functions, physiological inducers, and integration in regulating physiology. Moreover, we describe how organ-sensing screens in Drosophila can systematically identify novel conserved interorgan communication factors. Finally, we discuss how interorgan communication enabled and evolved as a result of specialization of organs. Together, we anticipate that future studies will establish a model for metazoan interorgan communication network (ICN) and how it is deregulated in disease.

BEND3 mediates transcriptional repression and heterochromatin organization

PubMed Central

Khan, Abid; Prasanth, Supriya G

2015-01-01

Transcription repression plays a central role in gene regulation. Transcription repressors utilize diverse strategies to mediate transcriptional repression. We have recently demonstrated that BEND3 (BANP, E5R and Nac1 domain) protein represses rDNA transcription by stabilizing a NoRC component. We discuss the role of BEND3 as a global regulator of gene expression and propose a model whereby BEND3 associates with chromatin remodeling complexes to modulate gene expression and heterochromatin organization. PMID:26507581

BEND3 mediates transcriptional repression and heterochromatin organization.

PubMed

Khan, Abid; Prasanth, Supriya G

2015-01-01

Transcription repression plays a central role in gene regulation. Transcription repressors utilize diverse strategies to mediate transcriptional repression. We have recently demonstrated that BEND3 (BANP, E5R and Nac1 domain) protein represses rDNA transcription by stabilizing a NoRC component. We discuss the role of BEND3 as a global regulator of gene expression and propose a model whereby BEND3 associates with chromatin remodeling complexes to modulate gene expression and heterochromatin organization.

Optimality models in the age of experimental evolution and genomics.

PubMed

Bull, J J; Wang, I-N

2010-09-01

Optimality models have been used to predict evolution of many properties of organisms. They typically neglect genetic details, whether by necessity or design. This omission is a common source of criticism, and although this limitation of optimality is widely acknowledged, it has mostly been defended rather than evaluated for its impact. Experimental adaptation of model organisms provides a new arena for testing optimality models and for simultaneously integrating genetics. First, an experimental context with a well-researched organism allows dissection of the evolutionary process to identify causes of model failure--whether the model is wrong about genetics or selection. Second, optimality models provide a meaningful context for the process and mechanics of evolution, and thus may be used to elicit realistic genetic bases of adaptation--an especially useful augmentation to well-researched genetic systems. A few studies of microbes have begun to pioneer this new direction. Incompatibility between the assumed and actual genetics has been demonstrated to be the cause of model failure in some cases. More interestingly, evolution at the phenotypic level has sometimes matched prediction even though the adaptive mutations defy mechanisms established by decades of classic genetic studies. Integration of experimental evolutionary tests with genetics heralds a new wave for optimality models and their extensions that does not merely emphasize the forces driving evolution.

Modeling Poroelastic Wave Propagation in a Real 2-D Complex Geological Structure Obtained via Self-Organizing Maps

NASA Astrophysics Data System (ADS)

Itzá Balam, Reymundo; Iturrarán-Viveros, Ursula; Parra, Jorge O.

2018-03-01

Two main stages of seismic modeling are geological model building and numerical computation of seismic response for the model. The quality of the computed seismic response is partly related to the type of model that is built. Therefore, the model building approaches become as important as seismic forward numerical methods. For this purpose, three petrophysical facies (sands, shales and limestones) are extracted from reflection seismic data and some seismic attributes via the clustering method called Self-Organizing Maps (SOM), which, in this context, serves as a geological model building tool. This model with all its properties is the input to the Optimal Implicit Staggered Finite Difference (OISFD) algorithm to create synthetic seismograms for poroelastic, poroacoustic and elastic media. The results show a good agreement between observed and 2-D synthetic seismograms. This demonstrates that the SOM classification method enables us to extract facies from seismic data and allows us to integrate the lithology at the borehole scale with the 2-D seismic data.

Graded effects in hierarchical figure-ground organization: reply to Peterson (1999).

PubMed

Vecera, S P; O'Reilly, R C

2000-06-01

An important issue in vision research concerns the order of visual processing. S. P. Vecera and R. C. O'Reilly (1998) presented an interactive, hierarchical model that placed figure-ground segregation prior to object recognition. M. A. Peterson (1999) critiqued this model, arguing that because it used ambiguous stimulus displays, figure-ground processing did not precede object processing. In the current article, the authors respond to Peterson's (1999) interpretation of ambiguity in the model and her interpretation of what it means for figure-ground processing to come before object recognition. The authors argue that complete stimulus ambiguity is not critical to the model and that figure-ground precedes object recognition architecturally in the model. The arguments are supported with additional simulation results and an experiment, demonstrating that top-down inputs can influence figure-ground organization in displays that contain stimulus cues.

Testing and extending the group engagement model: linkages between social identity, procedural justice, economic outcomes, and extrarole behavior.

PubMed

Blader, Steven L; Tyler, Tom R

2009-03-01

Two field studies tested and extended the group engagement model (Tyler & Blader, 2000, Tyler & Blader, 2003) by examining the model with regard to employee extrarole behavior. Consistent with the group engagement model's predictions, results of these studies indicate that the social identities employees form around their work groups and their organizations are strongly related to whether employees engage in extrarole behaviors. Moreover, the studies demonstrated that social identity explains the impact of other factors that have previously been linked to extrarole behavior. In particular, the findings indicate that social identity mediates the effect of procedural justice judgments and economic outcomes on supervisor ratings of extrarole behavior. Overall, these studies provide compelling indication that social identity is an important determinant of behavior within work organizations and provide strong support for the application of the group engagement model in organizational settings. (c) 2009 APA, all rights reserved.

Self-organizing linear output map (SOLO): An artificial neural network suitable for hydrologic modeling and analysis

NASA Astrophysics Data System (ADS)

Hsu, Kuo-Lin; Gupta, Hoshin V.; Gao, Xiaogang; Sorooshian, Soroosh; Imam, Bisher

2002-12-01

Artificial neural networks (ANNs) can be useful in the prediction of hydrologic variables, such as streamflow, particularly when the underlying processes have complex nonlinear interrelationships. However, conventional ANN structures suffer from network training issues that significantly limit their widespread application. This paper presents a multivariate ANN procedure entitled self-organizing linear output map (SOLO), whose structure has been designed for rapid, precise, and inexpensive estimation of network structure/parameters and system outputs. More important, SOLO provides features that facilitate insight into the underlying processes, thereby extending its usefulness beyond forecast applications as a tool for scientific investigations. These characteristics are demonstrated using a classic rainfall-runoff forecasting problem. Various aspects of model performance are evaluated in comparison with other commonly used modeling approaches, including multilayer feedforward ANNs, linear time series modeling, and conceptual rainfall-runoff modeling.

Soil fauna: key to new carbon models

NASA Astrophysics Data System (ADS)

Filser, Juliane; Faber, Jack H.; Tiunov, Alexei V.; Brussaard, Lijbert; Frouz, Jan; De Deyn, Gerlinde; Uvarov, Alexei V.; Berg, Matty P.; Lavelle, Patrick; Loreau, Michel; Wall, Diana H.; Querner, Pascal; Eijsackers, Herman; José Jiménez, Juan

2016-11-01

Soil organic matter (SOM) is key to maintaining soil fertility, mitigating climate change, combatting land degradation, and conserving above- and below-ground biodiversity and associated soil processes and ecosystem services. In order to derive management options for maintaining these essential services provided by soils, policy makers depend on robust, predictive models identifying key drivers of SOM dynamics. Existing SOM models and suggested guidelines for future SOM modelling are defined mostly in terms of plant residue quality and input and microbial decomposition, overlooking the significant regulation provided by soil fauna. The fauna controls almost any aspect of organic matter turnover, foremost by regulating the activity and functional composition of soil microorganisms and their physical-chemical connectivity with soil organic matter. We demonstrate a very strong impact of soil animals on carbon turnover, increasing or decreasing it by several dozen percent, sometimes even turning C sinks into C sources or vice versa. This is demonstrated not only for earthworms and other larger invertebrates but also for smaller fauna such as Collembola. We suggest that inclusion of soil animal activities (plant residue consumption and bioturbation altering the formation, depth, hydraulic properties and physical heterogeneity of soils) can fundamentally affect the predictive outcome of SOM models. Understanding direct and indirect impacts of soil fauna on nutrient availability, carbon sequestration, greenhouse gas emissions and plant growth is key to the understanding of SOM dynamics in the context of global carbon cycling models. We argue that explicit consideration of soil fauna is essential to make realistic modelling predictions on SOM dynamics and to detect expected non-linear responses of SOM dynamics to global change. We present a decision framework, to be further developed through the activities of KEYSOM, a European COST Action, for when mechanistic SOM models include soil fauna. The research activities of KEYSOM, such as field experiments and literature reviews, together with dialogue between empiricists and modellers, will inform how this is to be done.

A National Survey on the Taxonomy of Community Living Skills. Working Paper 87-4. COMPETE: Community-Based Model for Public-School Exit and Transition to Employment.

ERIC Educational Resources Information Center

Dever, Richard B.

This paper is a product of Project COMPETE, a service demonstration project undertaken for the purpose of developing and validating a model and training sequence to improve transition services for moderately, severely, and profoundly retarded youth. The paper describes the Taxonomy of Community Living Skills, an organized statement of…

[Inversion of organic matter content of the north fluvo-aquic soil based on hyperspectral and multi-spectra].

PubMed

Wang, Yan-Cang; Gu, Xiao-He; Zhu, Jin-Shan; Long, Hui-Ling; Xu, Peng; Liao, Qin-Hong

2014-01-01

The present study aims to assess the feasibility of multi-spectral data in monitoring soil organic matter content. The data source comes from hyperspectral measured under laboratory condition, and simulated multi-spectral data from the hyperspectral. According to the reflectance response functions of Landsat TM and HJ-CCD (the Environment and Disaster Reduction Small Satellites, HJ), the hyperspectra were resampled for the corresponding bands of multi-spectral sensors. The correlation between hyperspectral, simulated reflectance spectra and organic matter content was calculated, and used to extract the sensitive bands of the organic matter in the north fluvo-aquic soil. The partial least square regression (PLSR) method was used to establish experiential models to estimate soil organic matter content. Both root mean squared error (RMSE) and coefficient of the determination (R2) were introduced to test the precision and stability of the modes. Results demonstrate that compared with the hyperspectral data, the best model established by simulated multi-spectral data gives a good result for organic matter content, with R2=0.586, and RMSE=0.280. Therefore, using multi-spectral data to predict tide soil organic matter content is feasible.

Organic synthesis in experimental impact shocks

NASA Technical Reports Server (NTRS)

McKay, C. P.; Borucki, W. J.

1997-01-01

Laboratory simulations of shocks created with a high-energy laser demonstrate that the efficacy of organic production depends on the molecular, not just the elemental composition of the shocked gas. In a methane-rich mixture that simulates a low-temperature equilibrium mixture of cometary material, hydrogen cyanide and acetylene were produced with yields of 5 x 10(17) molecules per joule. Repeated shocking of the methane-rich mixture produced amine groups, suggesting the possible synthesis of amino acids. No organic molecules were produced in a carbon dioxide-rich mixture, which is at odds with thermodynamic equilibrium approaches to shock chemistry and has implications for the modeling of shock-produced organic molecules on early Earth.

Tradeoffs in Acceleration and Initialization of Superparameterized Global Atmospheric Models for MJO and Climate Science

NASA Astrophysics Data System (ADS)

Pritchard, M. S.; Bretherton, C. S.; DeMott, C. A.

2014-12-01

New trade-offs are discussed in the cloud superparameterization approach to explicitly representing deep convection in global climate models. Intrinsic predictability tests show that the memory of cloud-resolving-scale organization is not critical for producing desired modes of organized convection such as the Madden-Julian Oscillation (MJO). This has implications for the feasibility of data assimilation and real-world initialization for superparameterized weather forecasting. Climate simulation sensitivity tests demonstrate that 400% acceleration of cloud superparameterization is possible by restricting the 32-128 km scale regime without deteriorating the realism of the simulated MJO but the number of cloud resolving model grid columns is discovered to constrain the efficiency of vertical mixing, with consequences for the simulated liquid cloud climatology. Tuning opportunities for next generation accelerated superparameterized climate models are discussed.

Experimental Human Cell and Tissue Models of Pemphigus

PubMed Central

van der Wier, Gerda; Pas, Hendri H.; Jonkman, Marcel F.

2010-01-01

Pemphigus is a chronic mucocutaneous autoimmune bullous disease that is characterized by loss of cell-cell contact in skin and/or mucous membranes. Past research has successfully identified desmosomes as immunological targets and has demonstrated that acantholysis is initiated through direct binding of IgG. The exact mechanisms of acantholysis, however, are still missing. Experimental model systems have contributed considerably to today's knowledge and are still a favourite tool of research. In this paper we will describe to what extent human cell and tissue models represent the in vivo situation, for example, organ cultures of human skin, keratinocyte cultures, and human skin grafted on mice and, furthermore, how suitable they are to study the pathogenesis of pemphigus. Organ cultures closely mimic the architecture of the epidermis but are less suitable to answer posed biochemical questions. Cultured keratinocyte monolayers are convenient in this respect, but their desmosomal make-up in terms of adhesion molecules does not exactly reflect the in vivo situation. Reconstituted skin is a relatively new model that approaches organ culture. In models of human skin grafted on mice, acantholysis can be studied in actual human skin but now with all the advantages of an animal model. PMID:20585596

Bootstrapping of Life through Holonomy and Self-modification

NASA Astrophysics Data System (ADS)

Kazansky, Alexander B.

2010-11-01

Life on the Earth demonstrate not only adaptive, cognitive, particularly, anticipatory properties, but also active, transformative function to its local and global environment. As V. Vernadsky stated, life is a powerful geological force. Charles Darwin realized that too. In his last work [1] he proved, that earthworms through their vital activity in geological time scale are able to form and support contemporary structure of soil on the whole planet. Locally, through so-called process of niche construction [2] organisms virtually modifies abiotic and biotic factors of natural selection and thereby insert feedback loop in evolutionary process. Stigmergy [3] is one more form of indirect interaction of organisms via the environment by signs, left in local environment or just by performing working activity in swarms, leading to self-organization and coordination of actions in the process of refuges construction. In organization of life we can separate active, rigid, organism-like, autopoietic-like systems or less rigid, sympoietic, socio-biological type systems [4]. Nevertheless, all forms of life systems demonstrate so-called bootstrapping, or spontaneous process of self-organizing emergence. This process is feasible thanks to self-modification, and holonomy in their organization, or total reflexivity. Analysis of the role of indirect interactions in bootstrapping, made in this paper, is aimed at revealing relationships between concepts and making step to forming new systemic model of organization and evolution of special dual pair, biota and biosphere.

Organizational Communication and Culture: A Study of 10 Italian High-Technology Companies.

ERIC Educational Resources Information Center

Morley, Donald Dean; Shockley-Zalabak, Pamela; Cesaria, Ruggero

1997-01-01

Tests in international environments models previously developed within United States high-technology organizations. Demonstrates that relationships among organizational culture themes, employee values, organizational communication activities, and perceptions of a variety of organizational outcomes are similar but not identical for United States…

America's Favorite Pastime: Learning.

ERIC Educational Resources Information Center

Taylor, Gene

1989-01-01

Examines the role of "relief" teacher at a Navajo Reservation elementary boarding school: developer of academic projects based on student interests and abilities. Describes a whale project that involved building a life-size model, information searches, letter and report writing, and a student-organized demonstration of exhibits. (SV)

Working Model Hearts

ERIC Educational Resources Information Center

Brock, David

2009-01-01

Despite student interest, the heart is often a poorly understood topic in biology. To help students understand this vital organ's physiology, the author created this investigation activity involving the mammalian heart and its role in the circulatory system. Students design, build, and demonstrate working artificial "hearts" to exhibit what they…

Light Extraction From Solution-Based Processable Electrophosphorescent Organic Light-Emitting Diodes

NASA Astrophysics Data System (ADS)

Krummacher, Benjamin C.; Mathai, Mathew; So, Franky; Choulis, Stelios; Choong, And-En, Vi

2007-06-01

Molecular dye dispersed solution processable blue emitting organic light-emitting devices have been fabricated and the resulting devices exhibit efficiency as high as 25 cd/A. With down-conversion phosphors, white emitting devices have been demonstrated with peak efficiency of 38 cd/A and luminous efficiency of 25 lm/W. The high efficiencies have been a product of proper tuning of carrier transport, optimization of the location of the carrier recombination zone and, hence, microcavity effect, efficient down-conversion from blue to white light, and scattering/isotropic remission due to phosphor particles. An optical model has been developed to investigate all these effects. In contrast to the common misunderstanding that light out-coupling efficiency is about 22% and independent of device architecture, our device data and optical modeling results clearly demonstrated that the light out-coupling efficiency is strongly dependent on the exact location of the recombination zone. Estimating the device internal quantum efficiencies based on external quantum efficiencies without considering the device architecture could lead to erroneous conclusions.

B-Type Natriuretic Peptide Deletion Leads to Progressive Hypertension, Associated Organ Damage, and Reduced Survival: Novel Model for Human Hypertension.

PubMed

Holditch, Sara J; Schreiber, Claire A; Nini, Ryan; Tonne, Jason M; Peng, Kah-Whye; Geurts, Aron; Jacob, Howard J; Burnett, John C; Cataliotti, Alessandro; Ikeda, Yasuhiro

2015-07-01

Altered myocardial structure and function, secondary to chronically elevated blood pressure, are leading causes of heart failure and death. B-type natriuretic peptide (BNP), a guanylyl cyclase A agonist, is a cardiac hormone integral to cardiovascular regulation. Studies have demonstrated a causal relationship between reduced production or impaired BNP release and the development of human hypertension. However, the consequences of BNP insufficiency on blood pressure and hypertension-associated complications remain poorly understood. Therefore, the goal of this study was to create and characterize a novel model of BNP deficiency to investigate the effects of BNP absence on cardiac and renal structure, function, and survival. Genetic BNP deletion was generated in Dahl salt-sensitive rats. Compared with age-matched controls, BNP knockout rats demonstrated adult-onset hypertension. Increased left ventricular mass with hypertrophy and substantially augmented hypertrophy signaling pathway genes, developed in young adult knockout rats, which preceded hypertension. Prolonged hypertension led to increased cardiac stiffness, cardiac fibrosis, and thrombi formation. Significant elongation of the QT interval was detected at 9 months in knockout rats. Progressive nephropathy was also noted with proteinuria, fibrosis, and glomerular alterations in BNP knockout rats. End-organ damage contributed to a significant decline in overall survival. Systemic BNP overexpression reversed the phenotype of genetic BNP deletion. Our results demonstrate the critical role of BNP defect in the development of systemic hypertension and associated end-organ damage in adulthood. © 2015 American Heart Association, Inc.

Simulating secondary organic aerosol from missing diesel-related intermediate-volatility organic compound emissions during the Clean Air for London (ClearfLo) campaign

NASA Astrophysics Data System (ADS)

Ots, Riinu; Young, Dominique E.; Vieno, Massimo; Xu, Lu; Dunmore, Rachel E.; Allan, James D.; Coe, Hugh; Williams, Leah R.; Herndon, Scott C.; Ng, Nga L.; Hamilton, Jacqueline F.; Bergström, Robert; Di Marco, Chiara; Nemitz, Eiko; Mackenzie, Ian A.; Kuenen, Jeroen J. P.; Green, David C.; Reis, Stefan; Heal, Mathew R.

2016-05-01

We present high-resolution (5 km × 5 km) atmospheric chemical transport model (ACTM) simulations of the impact of newly estimated traffic-related emissions on secondary organic aerosol (SOA) formation over the UK for 2012. Our simulations include additional diesel-related intermediate-volatility organic compound (IVOC) emissions derived directly from comprehensive field measurements at an urban background site in London during the 2012 Clean Air for London (ClearfLo) campaign. Our IVOC emissions are added proportionally to VOC emissions, as opposed to proportionally to primary organic aerosol (POA) as has been done by previous ACTM studies seeking to simulate the effects of these missing emissions. Modelled concentrations are evaluated against hourly and daily measurements of organic aerosol (OA) components derived from aerosol mass spectrometer (AMS) measurements also made during the ClearfLo campaign at three sites in the London area. According to the model simulations, diesel-related IVOCs can explain on average ˜ 30 % of the annual SOA in and around London. Furthermore, the 90th percentile of modelled daily SOA concentrations for the whole year is 3.8 µg m-3, constituting a notable addition to total particulate matter. More measurements of these precursors (currently not included in official emissions inventories) is recommended. During the period of concurrent measurements, SOA concentrations at the Detling rural background location east of London were greater than at the central London location. The model shows that this was caused by an intense pollution plume with a strong gradient of imported SOA passing over the rural location. This demonstrates the value of modelling for supporting the interpretation of measurements taken at different sites or for short durations.

WE-AB-BRA-05: Fully Automatic Segmentation of Male Pelvic Organs On CT Without Manual Intervention

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Y; Lian, J; Chen, R

Purpose: We aim to develop a fully automatic tool for accurate contouring of major male pelvic organs in CT images for radiotherapy without any manual initialization, yet still achieving superior performance than the existing tools. Methods: A learning-based 3D deformable shape model was developed for automatic contouring. Specifically, we utilized a recent machine learning method, random forest, to jointly learn both image regressor and classifier for each organ. In particular, the image regressor is trained to predict the 3D displacement from each vertex of the 3D shape model towards the organ boundary based on the local image appearance around themore » location of this vertex. The predicted 3D displacements are then used to drive the 3D shape model towards the target organ. Once the shape model is deformed close to the target organ, it is further refined by an organ likelihood map estimated by the learned classifier. As the organ likelihood map provides good guideline for the organ boundary, the precise contouring Result could be achieved, by deforming the 3D shape model locally to fit boundaries in the organ likelihood map. Results: We applied our method to 29 previously-treated prostate cancer patients, each with one planning CT scan. Compared with manually delineated pelvic organs, our method obtains overlap ratios of 85.2%±3.74% for the prostate, 94.9%±1.62% for the bladder, and 84.7%±1.97% for the rectum, respectively. Conclusion: This work demonstrated feasibility of a novel machine-learning based approach for accurate and automatic contouring of major male pelvic organs. It shows the potential to replace the time-consuming and inconsistent manual contouring in the clinic. Also, compared with the existing works, our method is more accurate and also efficient since it does not require any manual intervention, such as manual landmark placement. Moreover, our method obtained very similar contouring results as the clinical experts. Project is partially support by a grant from NCI 1R01CA140413.« less

Victory for volunteerism? Scottish health board elections and participation in the welfare state.

PubMed

Greer, Scott L; Stewart, Ellen A; Wilson, Iain; Donnelly, Peter D

2014-04-01

This paper presents findings from a multimethod study of pilot elections held to choose members of health boards in the National Health Service in Scotland. We begin by proposing that much current public involvement practice is dominated by a volunteerist model, in which members of the public with time and skills to offer play essentially supportive and non-challenging roles within health care organizations. This model contrasts sharply with the adversarial, political model of electoral democracy. Nonetheless, drawing on a postal survey of voters, non-participant observation of Boards, and semi-structured interviews with candidates, elected Board members and other stakeholders, we demonstrate that the introduction of elections did not overcome the volunteerist slant of current public involvement with health care organizations. Far from offering a 'quick fix' for policymakers seeking to ensure accountability of health care organizations, elections may produce remarkably similar outcomes to existing mechanisms of public involvement. Copyright © 2014 Elsevier Ltd. All rights reserved.

Acellular organ scaffolds for tumor tissue engineering

NASA Astrophysics Data System (ADS)

Guller, Anna; Trusova, Inna; Petersen, Elena; Shekhter, Anatoly; Kurkov, Alexander; Qian, Yi; Zvyagin, Andrei

2015-12-01

Rationale: Tissue engineering (TE) is an emerging alternative approach to create models of human malignant tumors for experimental oncology, personalized medicine and drug discovery studies. Being the bottom-up strategy, TE provides an opportunity to control and explore the role of every component of the model system, including cellular populations, supportive scaffolds and signalling molecules. Objectives: As an initial step to create a new ex vivo TE model of cancer, we optimized protocols to obtain organ-specific acellular matrices and evaluated their potential as TE scaffolds for culture of normal and tumor cells. Methods and results: Effective decellularization of animals' kidneys, ureter, lungs, heart, and liver has been achieved by detergent-based processing. The obtained scaffolds demonstrated biocompatibility and growthsupporting potential in combination with normal (Vero, MDCK) and tumor cell lines (C26, B16). Acellular scaffolds and TE constructs have been characterized and compared with morphological methods. Conclusions: The proposed methodology allows creation of sustainable 3D tumor TE constructs to explore the role of organ-specific cell-matrix interaction in tumorigenesis.

A portable expression resource for engineering cross-species genetic circuits and pathways

PubMed Central

Kushwaha, Manish; Salis, Howard M.

2015-01-01

Genetic circuits and metabolic pathways can be reengineered to allow organisms to process signals and manufacture useful chemicals. However, their functions currently rely on organism-specific regulatory parts, fragmenting synthetic biology and metabolic engineering into host-specific domains. To unify efforts, here we have engineered a cross-species expression resource that enables circuits and pathways to reuse the same genetic parts, while functioning similarly across diverse organisms. Our engineered system combines mixed feedback control loops and cross-species translation signals to autonomously self-regulate expression of an orthogonal polymerase without host-specific promoters, achieving nontoxic and tuneable gene expression in diverse Gram-positive and Gram-negative bacteria. Combining 50 characterized system variants with mechanistic modelling, we show how the cross-species expression resource's dynamics, capacity and toxicity are controlled by the control loops' architecture and feedback strengths. We also demonstrate one application of the resource by reusing the same genetic parts to express a biosynthesis pathway in both model and non-model hosts. PMID:26184393

On the Computational Power of Spiking Neural P Systems with Self-Organization.

PubMed

Wang, Xun; Song, Tao; Gong, Faming; Zheng, Pan

2016-06-10

Neural-like computing models are versatile computing mechanisms in the field of artificial intelligence. Spiking neural P systems (SN P systems for short) are one of the recently developed spiking neural network models inspired by the way neurons communicate. The communications among neurons are essentially achieved by spikes, i. e. short electrical pulses. In terms of motivation, SN P systems fall into the third generation of neural network models. In this study, a novel variant of SN P systems, namely SN P systems with self-organization, is introduced, and the computational power of the system is investigated and evaluated. It is proved that SN P systems with self-organization are capable of computing and accept the family of sets of Turing computable natural numbers. Moreover, with 87 neurons the system can compute any Turing computable recursive function, thus achieves Turing universality. These results demonstrate promising initiatives to solve an open problem arisen by Gh Păun.

On the Computational Power of Spiking Neural P Systems with Self-Organization

PubMed Central

Wang, Xun; Song, Tao; Gong, Faming; Zheng, Pan

2016-01-01

Neural-like computing models are versatile computing mechanisms in the field of artificial intelligence. Spiking neural P systems (SN P systems for short) are one of the recently developed spiking neural network models inspired by the way neurons communicate. The communications among neurons are essentially achieved by spikes, i. e. short electrical pulses. In terms of motivation, SN P systems fall into the third generation of neural network models. In this study, a novel variant of SN P systems, namely SN P systems with self-organization, is introduced, and the computational power of the system is investigated and evaluated. It is proved that SN P systems with self-organization are capable of computing and accept the family of sets of Turing computable natural numbers. Moreover, with 87 neurons the system can compute any Turing computable recursive function, thus achieves Turing universality. These results demonstrate promising initiatives to solve an open problem arisen by Gh Păun. PMID:27283843

Deciphering the Minimal Algorithm for Development and Information-genesis

NASA Astrophysics Data System (ADS)

Li, Zhiyuan; Tang, Chao; Li, Hao

During development, cells with identical genomes acquires different fates in a highly organized manner. In order to decipher the principles underlining development, we used C.elegans as the model organism. Based on a large set of microscopy imaging, we first constructed a ``standard worm'' in silico: from the single zygotic cell to about 500 cell stage, the lineage, position, cell-cell contact and gene expression dynamics are quantified for each cell in order to investigate principles underlining these intensive data. Next, we reverse-engineered the possible gene-gene/cell-cell interaction rules that are capable of running a dynamic model recapitulating the early fate decisions during C.elegans development. we further formulized the C.elegans embryogenesis in the language of information genesis. Analysis towards data and model uncovered the global landscape of development in the cell fate space, suggested possible gene regulatory architectures and cell signaling processes, revealed diversity and robustness as the essential trade-offs in development, and demonstrated general strategies in building multicellular organisms.

Exposure assessment of environmental organic chemicals at contaminated sites: a multicompartment modelling approach.

PubMed

Matthies, M

2003-04-11

For the prevention of future damages from chemicals at large contaminated sites, all transfer pathways leading to the exposure of man and vulnerable ecosystems have to be taken into account. For organic contaminants, the uptake into vegetation is the major entry route for the transfer into the food chains. Lipophilic substances are taken up by roots but are not translocated with the transpiration stream. Atmospheric background concentrations have a significant impact on foliage contamination due to the effective gaseous and particle deposition. Vegetables can also be contaminated after irrigation with contaminated water supplied by groundwater wells. By means of a multicompartment model, the various uptake processes into roots and foliage as well as the transformation and translocation processes are described and the concentration pattern resulting from daily irrigation with methyl-t-butyl ether in the edible parts is simulated. The results demonstrate the advantage of a dynamic multicompartment model over the static environmental quality standard approach in terms of derivation of possible exposure reduction measures for organic chemicals.

On the Computational Power of Spiking Neural P Systems with Self-Organization

NASA Astrophysics Data System (ADS)

Wang, Xun; Song, Tao; Gong, Faming; Zheng, Pan

2016-06-01

Neural-like computing models are versatile computing mechanisms in the field of artificial intelligence. Spiking neural P systems (SN P systems for short) are one of the recently developed spiking neural network models inspired by the way neurons communicate. The communications among neurons are essentially achieved by spikes, i. e. short electrical pulses. In terms of motivation, SN P systems fall into the third generation of neural network models. In this study, a novel variant of SN P systems, namely SN P systems with self-organization, is introduced, and the computational power of the system is investigated and evaluated. It is proved that SN P systems with self-organization are capable of computing and accept the family of sets of Turing computable natural numbers. Moreover, with 87 neurons the system can compute any Turing computable recursive function, thus achieves Turing universality. These results demonstrate promising initiatives to solve an open problem arisen by Gh Păun.

Self-Organizing Hidden Markov Model Map (SOHMMM).

PubMed

Ferles, Christos; Stafylopatis, Andreas

2013-12-01

A hybrid approach combining the Self-Organizing Map (SOM) and the Hidden Markov Model (HMM) is presented. The Self-Organizing Hidden Markov Model Map (SOHMMM) establishes a cross-section between the theoretic foundations and algorithmic realizations of its constituents. The respective architectures and learning methodologies are fused in an attempt to meet the increasing requirements imposed by the properties of deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and protein chain molecules. The fusion and synergy of the SOM unsupervised training and the HMM dynamic programming algorithms bring forth a novel on-line gradient descent unsupervised learning algorithm, which is fully integrated into the SOHMMM. Since the SOHMMM carries out probabilistic sequence analysis with little or no prior knowledge, it can have a variety of applications in clustering, dimensionality reduction and visualization of large-scale sequence spaces, and also, in sequence discrimination, search and classification. Two series of experiments based on artificial sequence data and splice junction gene sequences demonstrate the SOHMMM's characteristics and capabilities. Copyright © 2013 Elsevier Ltd. All rights reserved.

Zebrafish as a model system to study toxicology.

PubMed

Dai, Yu-Jie; Jia, Yong-Fang; Chen, Na; Bian, Wan-Ping; Li, Qin-Kai; Ma, Yan-Bo; Chen, Yan-Ling; Pei, De-Sheng

2014-01-01

Monitoring and assessing the effects of contaminants in the aquatic eco-environment is critical in protecting human health and the environment. The zebrafish has been widely used as a prominent model organism in different fields because of its small size, low cost, diverse adaptability, short breeding cycle, high fecundity, and transparent embryos. Recent studies have demonstrated that zebrafish sensitivity can aid in monitoring environmental contaminants, especially with the application of transgenic technology in this area. The present review provides a brief overview of recent studies on wild-type and transgenic zebrafish as a model system to monitor toxic heavy metals, endocrine disruptors, and organic pollutants for toxicology. The authors address the new direction of developing high-throughput detection of genetically modified transparent zebrafish to open a new window for monitoring environmental pollutants. © 2013 SETAC.

76 FR 35185 - Submission for OMB Review; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-16

..., filing of petitions and applications and agency #0;statements of organization and functions are examples... develop and test methods of providing access to food for children in urban and rural areas during the... each Summer Food Service Program (SFSP) enhancement demonstration model on participation and meal...

Transmembrane Polyproline Helix.

PubMed

Kubyshkin, Vladimir; Grage, Stephan L; Bürck, Jochen; Ulrich, Anne S; Budisa, Nediljko

2018-05-03

The third most abundant polypeptide conformation in nature, the polyproline-II helix, is a polar, extended secondary structure with a local organization stabilized by intercarbonyl interactions within the peptide chain. Here we design a hydrophobic polyproline-II helical peptide based on an oligomeric octahydroindole-2-carboxylic acid scaffold and demonstrate its transmembrane alignment in model lipid bilayers by means of solid-state 19 F NMR. As result, we provide a first example of a purely artificial transmembrane peptide with a structural organization that is not based on hydrogen-bonding.

VPP Star recognition

NASA Image and Video Library

2011-06-09

Stennis Space Center Deputy Director Rick Gilbrech (right) accepts a plaque designating the test facility as a Voluntary Protection Program Star site. Presenting the plaque is Clyde Payne, area director for the Occupational Safety and Health Administration in Jackson, Miss. OSHA established VPP in 1982 as a proactive safety management model to recognize excellence in safety and health. Since then, more than 2,000 organizations have been designated VPP Star sites. To reach that goal, an organization must demonstrate comprehensive and successful safety and health management programs in the workplace.

Electronic Health Record (EHR) Organizational Change: Explaining Resistance Through Profession, Organizational Experience, and EHR Communication Quality.

PubMed

Barrett, Ashley K

2018-04-01

The American Recovery and Reinvestment Act passed by the U.S. government in 2009 mandates that all healthcare organizations adopt a certified electronic health record (EHR) system by 2015. Failure to comply will result in Medicare reimbursement penalties, which steadily increase with each year of delinquency. There are several repercussions of this seemingly top-down, rule-bound organizational change-one of which is employee resistance. Given the penalties for violating EHR meaningful use standards are ongoing, resistance to this mandate presents a serious issue for healthcare organizations. This study surveyed 345 employees in one healthcare organization that recently implemented an EHR. Analysis of variance results offer theoretical and pragmatic contributions by demonstrating physicians, nurses, and employees with more experience in their organization are the most resistant to EHR change. The job characteristics model is used to explain these findings. Hierarchical regression analyses also demonstrate the quality of communication surrounding EHR implementation-from both formal and informal sources-is negatively associated with EHR resistance and positively associated with perceived EHR implementation success and EHR's perceived relative advantage.

Direct Observation of a Carbon Filament in Water-Resistant Organic Memory.

PubMed

Lee, Byung-Hyun; Bae, Hagyoul; Seong, Hyejeong; Lee, Dong-Il; Park, Hongkeun; Choi, Young Joo; Im, Sung-Gap; Kim, Sang Ouk; Choi, Yang-Kyu

2015-07-28

The memory for the Internet of Things (IoT) requires versatile characteristics such as flexibility, wearability, and stability in outdoor environments. Resistive random access memory (RRAM) to harness a simple structure and organic material with good flexibility can be an attractive candidate for IoT memory. However, its solution-oriented process and unclear switching mechanism are critical problems. Here we demonstrate iCVD polymer-intercalated RRAM (i-RRAM). i-RRAM exhibits robust flexibility and versatile wearability on any substrate. Stable operation of i-RRAM, even in water, is demonstrated, which is the first experimental presentation of water-resistant organic memory without any waterproof protection package. Moreover, the direct observation of a carbon filament is also reported for the first time using transmission electron microscopy, which puts an end to the controversy surrounding the switching mechanism. Therefore, reproducibility is feasible through comprehensive modeling. Furthermore, a carbon filament is superior to a metal filament in terms of the design window and selection of the electrode material. These results suggest an alternative to solve the critical issues of organic RRAM and an optimized memory type suitable for the IoT era.

Making Electronic Health Records (EHRs) Work: Informal Talk and Workarounds in Healthcare Organizations.

PubMed

Barrett, Ashley K; Stephens, Keri K

2017-08-01

A key provision of the American Recovery and Reinvestment Act of 2009 mandated that electronic health records (EHR) be adopted in US healthcare organizations by 2015. The purpose of this study is to examine the communicative processes involved as healthcare workers implement an EHR and make changes, known as workarounds. Guided by theories in social influence, and diffusion of innovations, we conducted a survey of healthcare professionals using an EHR system in an organization. Our structural equation modeling (SEM) and multiple regression results reveal coworker communication, in the form of informal social support and feedback, play an important role in whether people engage in workarounds. Understanding this relationship is important because our study also demonstrates that workarounds predict healthcare employees' overall satisfaction with the EHR system. Specifically, workarounds are associated with higher perceptions of the EHR's relative advantage, higher perceptions of EHR implementation success, and lower levels of resistance to EHR change. This study offers a health communication contribution to the growing research on EHR systems and demonstrates the persuasive effects that coworkers have on new technology use in healthcare organizations.

Basic principles of information technology organization in health care institutions.

PubMed

Mitchell, J A

1997-01-01

This paper focuses on the basic principles of information technology (IT) organization within health sciences centers. The paper considers the placement of the leader of the IT effort within the health sciences administrative structure and the organization of the IT unit. A case study of the University of Missouri-Columbia Health Sciences Center demonstrates how a role-based organizational model for IT support can be effective for determining the boundary between centralized and decentralized organizations. The conclusions are that the IT leader needs to be positioned with other institutional leaders who are making strategic decisions, and that the internal IT structure needs to be a role-based hybrid of centralized and decentralized units. The IT leader needs to understand the mission of the organization and actively use change-management techniques.

Investigation of microcantilever array with ordered nanoporous coatings for selective chemical detection

NASA Astrophysics Data System (ADS)

Lee, J.-H.; Houk, R. T. J.; Robinson, A.; Greathouse, J. A.; Thornberg, S. M.; Allendorf, M. D.; Hesketh, P. J.

2010-04-01

In this paper we demonstrate the potential for novel nanoporous framework materials (NFM) such as metal-organic frameworks (MOFs) to provide selectivity and sensitivity to a broad range of analytes including explosives, nerve agents, and volatile organic compounds (VOCs). NFM are highly ordered, crystalline materials with considerable synthetic flexibility resulting from the presence of both organic and inorganic components within their structure. Detection of chemical weapons of mass destruction (CWMD), explosives, toxic industrial chemicals (TICs), and volatile organic compounds (VOCs) using micro-electro-mechanical-systems (MEMS) devices, such as microcantilevers and surface acoustic wave sensors, requires the use of recognition layers to impart selectivity. Traditional organic polymers are dense, impeding analyte uptake and slowing sensor response. The nanoporosity and ultrahigh surface areas of NFM enhance transport into and out of the NFM layer, improving response times, and their ordered structure enables structural tuning to impart selectivity. Here we describe experiments and modeling aimed at creating NFM layers tailored to the detection of water vapor, explosives, CWMD, and VOCs, and their integration with the surfaces of MEMS devices. Force field models show that a high degree of chemical selectivity is feasible. For example, using a suite of MOFs it should be possible to select for explosives vs. CWMD, VM vs. GA (nerve agents), and anthracene vs. naphthalene (VOCs). We will also demonstrate the integration of various NFM with the surfaces of MEMS devices and describe new synthetic methods developed to improve the quality of VFM coatings. Finally, MOF-coated MEMS devices show how temperature changes can be tuned to improve response times, selectivity, and sensitivity.

The feasibility of a scanner-independent technique to estimate organ dose from MDCT scans: Using CTDI{sub vol} to account for differences between scanners

DOE Office of Scientific and Technical Information (OSTI.GOV)

Turner, Adam C.; Zankl, Maria; DeMarco, John J.

2010-04-15

Purpose: Monte Carlo radiation transport techniques have made it possible to accurately estimate the radiation dose to radiosensitive organs in patient models from scans performed with modern multidetector row computed tomography (MDCT) scanners. However, there is considerable variation in organ doses across scanners, even when similar acquisition conditions are used. The purpose of this study was to investigate the feasibility of a technique to estimate organ doses that would be scanner independent. This was accomplished by assessing the ability of CTDI{sub vol} measurements to account for differences in MDCT scanners that lead to organ dose differences. Methods: Monte Carlo simulationsmore » of 64-slice MDCT scanners from each of the four major manufacturers were performed. An adult female patient model from the GSF family of voxelized phantoms was used in which all ICRP Publication 103 radiosensitive organs were identified. A 120 kVp, full-body helical scan with a pitch of 1 was simulated for each scanner using similar scan protocols across scanners. From each simulated scan, the radiation dose to each organ was obtained on a per mA s basis (mGy/mA s). In addition, CTDI{sub vol} values were obtained from each scanner for the selected scan parameters. Then, to demonstrate the feasibility of generating organ dose estimates from scanner-independent coefficients, the simulated organ dose values resulting from each scanner were normalized by the CTDI{sub vol} value for those acquisition conditions. Results: CTDI{sub vol} values across scanners showed considerable variation as the coefficient of variation (CoV) across scanners was 34.1%. The simulated patient scans also demonstrated considerable differences in organ dose values, which varied by up to a factor of approximately 2 between some of the scanners. The CoV across scanners for the simulated organ doses ranged from 26.7% (for the adrenals) to 37.7% (for the thyroid), with a mean CoV of 31.5% across all organs. However, when organ doses are normalized by CTDI{sub vol} values, the differences across scanners become very small. For the CTDI{sub vol}, normalized dose values the CoVs across scanners for different organs ranged from a minimum of 2.4% (for skin tissue) to a maximum of 8.5% (for the adrenals) with a mean of 5.2%. Conclusions: This work has revealed that there is considerable variation among modern MDCT scanners in both CTDI{sub vol} and organ dose values. Because these variations are similar, CTDI{sub vol} can be used as a normalization factor with excellent results. This demonstrates the feasibility of establishing scanner-independent organ dose estimates by using CTDI{sub vol} to account for the differences between scanners.« less

Imaging of mesoscopic-scale organisms using selective-plane optoacoustic tomography.

PubMed

Razansky, Daniel; Vinegoni, Claudio; Ntziachristos, Vasilis

2009-05-07

Mesoscopic-scale living organisms (i.e. 1 mm to 1 cm sized) remain largely inaccessible by current optical imaging methods due to intensive light scattering in tissues. Therefore, imaging of many important model organisms, such as insects, fishes, worms and similarly sized biological specimens, is currently limited to embryonic or other transparent stages of development. This makes it difficult to relate embryonic cellular and molecular mechanisms to consequences in organ function and animal behavior in more advanced stages and adults. Herein, we have developed a selective-plane illumination optoacoustic tomography technique for in vivo imaging of optically diffusive organisms and tissues. The method is capable of whole-body imaging at depths from the sub-millimeter up to centimeter range with a scalable spatial resolution in the order of magnitude of a few tenths of microns. In contrast to pure optical methods, the spatial resolution here is not determined nor limited by light diffusion; therefore, such performance cannot be achieved by any other optical imaging technology developed so far. The utility of the method is demonstrated on several whole-body models and small-animal extremities.

RUNX in Invertebrates.

PubMed

Hughes, S; Woollard, A

2017-01-01

Runx genes have been identified in all metazoans and considerable conservation of function observed across a wide range of phyla. Thus, insight gained from studying simple model organisms is invaluable in understanding RUNX biology in higher animals. Consequently, this chapter will focus on the Runx genes in the diploblasts, which includes sea anemones and sponges, as well as the lower triploblasts, including the sea urchin, nematode, planaria and insect. Due to the high degree of functional redundancy amongst vertebrate Runx genes, simpler model organisms with a solo Runx gene, like C. elegans, are invaluable systems in which to probe the molecular basis of RUNX function within a whole organism. Additionally, comparative analyses of Runx sequence and function allows for the development of novel evolutionary insights. Strikingly, recent data has emerged that reveals the presence of a Runx gene in a protist, demonstrating even more widespread occurrence of Runx genes than was previously thought. This review will summarize recent progress in using invertebrate organisms to investigate RUNX function during development and regeneration, highlighting emerging unifying themes.

A model for capacity-building in AIDS prevention programs.

PubMed

Ramos, Rebeca L; Ferreira-Pinto, João B

2002-06-01

This article discusses a collaboratively organizational capacity-building model for agencies engaged in HIV/AIDS prevention. The cooperative training approach (CTA) utilized by the Training and Technical Assistance Program trained participants to incorporate learned skills into their daily work practices, and to become trainers to help disseminate their newly acquired skills, first to others in their own organization and later to other organizations. The CTA was successfully implemented among 285 community-based organizations (CBOs) serving predominantly Hispanics in the U.S.-Mexico border region. The program evaluation demonstrated that it has significantly upgraded the program implementation capability and the organizational infrastructure of the participating organizations resulting in improved delivery of services to their clients. Furthermore, it fostered networking and collaboration for the development of sustainable training and technical assistance networks of agency staff skilled in organizational capacity building. It is suggested that funding agencies examine the feasibility of using this approach to increase the organizational capacity of CBOs involved in HIV/AIDS prevention.

A generative model for segmentation of tumor and organs-at-risk for radiation therapy planning of glioblastoma patients

NASA Astrophysics Data System (ADS)

Agn, Mikael; Law, Ian; Munck af Rosenschöld, Per; Van Leemput, Koen

2016-03-01

We present a fully automated generative method for simultaneous brain tumor and organs-at-risk segmentation in multi-modal magnetic resonance images. The method combines an existing whole-brain segmentation technique with a spatial tumor prior, which uses convolutional restricted Boltzmann machines to model tumor shape. The method is not tuned to any specific imaging protocol and can simultaneously segment the gross tumor volume, peritumoral edema and healthy tissue structures relevant for radiotherapy planning. We validate the method on a manually delineated clinical data set of glioblastoma patients by comparing segmentations of gross tumor volume, brainstem and hippocampus. The preliminary results demonstrate the feasibility of the method.

Diagnostic Air Quality Model Evaluation of Source-Specific ...

EPA Pesticide Factsheets

Ambient measurements of 78 source-specific tracers of primary and secondary carbonaceous fine particulate matter collected at four midwestern United States locations over a full year (March 2004–February 2005) provided an unprecedented opportunity to diagnostically evaluate the results of a numerical air quality model. Previous analyses of these measurements demonstrated excellent mass closure for the variety of contributing sources. In this study, a carbon-apportionment version of the Community Multiscale Air Quality (CMAQ) model was used to track primary organic and elemental carbon emissions from 15 independent sources such as mobile sources and biomass burning in addition to four precursor-specific classes of secondary organic aerosol (SOA) originating from isoprene, terpenes, aromatics, and sesquiterpenes. Conversion of the source-resolved model output into organic tracer concentrations yielded a total of 2416 data pairs for comparison with observations. While emission source contributions to the total model bias varied by season and measurement location, the largest absolute bias of −0.55 μgC/m3 was attributed to insufficient isoprene SOA in the summertime CMAQ simulation. Biomass combustion was responsible for the second largest summertime model bias (−0.46 μgC/m3 on average). Several instances of compensating errors were also evident; model underpredictions in some sectors were masked by overpredictions in others. The National Exposure Research L

Diagnostic air quality model evaluation of source-specific primary and secondary fine particulate carbon.

PubMed

Napelenok, Sergey L; Simon, Heather; Bhave, Prakash V; Pye, Havala O T; Pouliot, George A; Sheesley, Rebecca J; Schauer, James J

2014-01-01

Ambient measurements of 78 source-specific tracers of primary and secondary carbonaceous fine particulate matter collected at four midwestern United States locations over a full year (March 2004-February 2005) provided an unprecedented opportunity to diagnostically evaluate the results of a numerical air quality model. Previous analyses of these measurements demonstrated excellent mass closure for the variety of contributing sources. In this study, a carbon-apportionment version of the Community Multiscale Air Quality (CMAQ) model was used to track primary organic and elemental carbon emissions from 15 independent sources such as mobile sources and biomass burning in addition to four precursor-specific classes of secondary organic aerosol (SOA) originating from isoprene, terpenes, aromatics, and sesquiterpenes. Conversion of the source-resolved model output into organic tracer concentrations yielded a total of 2416 data pairs for comparison with observations. While emission source contributions to the total model bias varied by season and measurement location, the largest absolute bias of -0.55 μgC/m(3) was attributed to insufficient isoprene SOA in the summertime CMAQ simulation. Biomass combustion was responsible for the second largest summertime model bias (-0.46 μgC/m(3) on average). Several instances of compensating errors were also evident; model underpredictions in some sectors were masked by overpredictions in others.

2 H-fractionations during the biosynthesis of carbohydrates and lipids imprint a metabolic signal on the δ2 H values of plant organic compounds.

PubMed

Cormier, Marc-André; Werner, Roland A; Sauer, Peter E; Gröcke, Darren R; Leuenberger, Markus C; Wieloch, Thomas; Schleucher, Jürgen; Kahmen, Ansgar

2018-04-01

Hydrogen (H) isotope ratio (δ 2 H) analyses of plant organic compounds have been applied to assess ecohydrological processes in the environment despite a large part of the δ 2 H variability observed in plant compounds not being fully elucidated. We present a conceptual biochemical model based on empirical H isotope data that we generated in two complementary experiments that clarifies a large part of the unexplained variability in the δ 2 H values of plant organic compounds. The experiments demonstrate that information recorded in the δ 2 H values of plant organic compounds goes beyond hydrological signals and can also contain important information on the carbon and energy metabolism of plants. Our model explains where 2 H-fractionations occur in the biosynthesis of plant organic compounds and how these 2 H-fractionations are tightly coupled to a plant's carbon and energy metabolism. Our model also provides a mechanistic basis to introduce H isotopes in plant organic compounds as a new metabolic proxy for the carbon and energy metabolism of plants and ecosystems. Such a new metabolic proxy has the potential to be applied in a broad range of disciplines, including plant and ecosystem physiology, biogeochemistry and palaeoecology. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

The mapping of eccentricity and meridional angle onto orthogonal axes in the primary visual cortex: an activity-dependent developmental model.

PubMed

Philips, Ryan T; Chakravarthy, V Srinivasa

2015-01-01

Primate vision research has shown that in the retinotopic map of the primary visual cortex, eccentricity and meridional angle are mapped onto two orthogonal axes: whereas the eccentricity is mapped onto the nasotemporal axis, the meridional angle is mapped onto the dorsoventral axis. Theoretically such a map has been approximated by a complex log map. Neural models with correlational learning have explained the development of other visual maps like orientation maps and ocular-dominance maps. In this paper it is demonstrated that activity based mechanisms can drive a self-organizing map (SOM) into such a configuration that dilations and rotations of a particular image (in this case a rectangular bar) are mapped onto orthogonal axes. We further demonstrate using the Laterally Interconnected Synergetically Self Organizing Map (LISSOM) model, with an appropriate boundary and realistic initial conditions, that a retinotopic map which maps eccentricity and meridional angle to the horizontal and vertical axes respectively can be developed. This developed map bears a strong resemblance to the complex log map. We also simulated lesion studies which indicate that the lateral excitatory connections play a crucial role in development of the retinotopic map.

An incremental anomaly detection model for virtual machines.

PubMed

Zhang, Hancui; Chen, Shuyu; Liu, Jun; Zhou, Zhen; Wu, Tianshu

2017-01-01

Self-Organizing Map (SOM) algorithm as an unsupervised learning method has been applied in anomaly detection due to its capabilities of self-organizing and automatic anomaly prediction. However, because of the algorithm is initialized in random, it takes a long time to train a detection model. Besides, the Cloud platforms with large scale virtual machines are prone to performance anomalies due to their high dynamic and resource sharing characters, which makes the algorithm present a low accuracy and a low scalability. To address these problems, an Improved Incremental Self-Organizing Map (IISOM) model is proposed for anomaly detection of virtual machines. In this model, a heuristic-based initialization algorithm and a Weighted Euclidean Distance (WED) algorithm are introduced into SOM to speed up the training process and improve model quality. Meanwhile, a neighborhood-based searching algorithm is presented to accelerate the detection time by taking into account the large scale and high dynamic features of virtual machines on cloud platform. To demonstrate the effectiveness, experiments on a common benchmark KDD Cup dataset and a real dataset have been performed. Results suggest that IISOM has advantages in accuracy and convergence velocity of anomaly detection for virtual machines on cloud platform.

An incremental anomaly detection model for virtual machines

PubMed Central

Zhang, Hancui; Chen, Shuyu; Liu, Jun; Zhou, Zhen; Wu, Tianshu

2017-01-01

Self-Organizing Map (SOM) algorithm as an unsupervised learning method has been applied in anomaly detection due to its capabilities of self-organizing and automatic anomaly prediction. However, because of the algorithm is initialized in random, it takes a long time to train a detection model. Besides, the Cloud platforms with large scale virtual machines are prone to performance anomalies due to their high dynamic and resource sharing characters, which makes the algorithm present a low accuracy and a low scalability. To address these problems, an Improved Incremental Self-Organizing Map (IISOM) model is proposed for anomaly detection of virtual machines. In this model, a heuristic-based initialization algorithm and a Weighted Euclidean Distance (WED) algorithm are introduced into SOM to speed up the training process and improve model quality. Meanwhile, a neighborhood-based searching algorithm is presented to accelerate the detection time by taking into account the large scale and high dynamic features of virtual machines on cloud platform. To demonstrate the effectiveness, experiments on a common benchmark KDD Cup dataset and a real dataset have been performed. Results suggest that IISOM has advantages in accuracy and convergence velocity of anomaly detection for virtual machines on cloud platform. PMID:29117245

Organic Pollutant Penetration through Fruit Polyester Skin: A Modified Three-compartment Diffusion Model

PubMed Central

Li, Yungui; Li, Qingqing; Chen, Baoliang

2016-01-01

The surface of plants is covered by a continuous but heterogeneous cuticular membrane (CM). Serving as the first protective barrier, the uptake and transport behavior of organic pollutants at this interface continue to engage the research efforts of environmental chemist. To date, the contributions of cuticular components as a defense against the organic pollutants penetration remain unresolved. In this study, the unsteady-state penetration characteristics of phenanthrene (PHE) through isolated fruit CM was investigated. PHE penetration was differentiated by three cuticular compartments: epicuticular waxes (EW), cuticle proper (CP) and cuticular layer (CL). The driving force for PHE penetration was ascribed to the sharp concentration gradient built up endogenously by cuticular compartments with different lipophilic affinities. A modified penetration model was established and verified in terms of its general suitability for the hydrophobic chemicals and CMs of various plant species (apple, tomato and potato). The new three-compartment model demonstrates much higher accuracy in characterizing the uptake and transport behavior of semivolatile chemicals with fewer limitations in terms of environmental conditions and complexity (e.g., coexisting contaminants and temperature). This model could contribute to a more comprehensive understanding on the role of polymeric lipids in the organic pollutant sorption and transport into plants. PMID:27009902

Uncertainties in SOA Formation from the Photooxidation of α-pinene

NASA Astrophysics Data System (ADS)

McVay, R.; Zhang, X.; Aumont, B.; Valorso, R.; Camredon, M.; La, S.; Seinfeld, J.

2015-12-01

Explicit chemical models such as GECKO-A (the Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere) enable detailed modeling of gas-phase photooxidation and secondary organic aerosol (SOA) formation. Comparison between these explicit models and chamber experiments can provide insight into processes that are missing or unknown in these models. GECKO-A is used to model seven SOA formation experiments from α-pinene photooxidation conducted at varying seed particle concentrations with varying oxidation rates. We investigate various physical and chemical processes to evaluate the extent of agreement between the experiments and the model predictions. We examine the effect of vapor wall loss on SOA formation and how the importance of this effect changes at different oxidation rates. Proposed gas-phase autoxidation mechanisms are shown to significantly affect SOA predictions. The potential effects of particle-phase dimerization and condensed-phase photolysis are investigated. We demonstrate the extent to which SOA predictions in the α-pinene photooxidation system depend on uncertainties in the chemical mechanism.

Biochemical Composition and Assembly of Biosilica-associated Insoluble Organic Matrices from the Diatom Thalassiosira pseudonana*

PubMed Central

Kotzsch, Alexander; Pawolski, Damian; Milentyev, Alexander; Shevchenko, Anna; Scheffel, André; Poulsen, Nicole; Shevchenko, Andrej; Kröger, Nils

2016-01-01

The nano- and micropatterned biosilica cell walls of diatoms are remarkable examples of biological morphogenesis and possess highly interesting material properties. Only recently has it been demonstrated that biosilica-associated organic structures with specific nanopatterns (termed insoluble organic matrices) are general components of diatom biosilica. The model diatom Thalassiosira pseudonana contains three types of insoluble organic matrices: chitin meshworks, organic microrings, and organic microplates, the latter being described in the present study for the first time. To date, little is known about the molecular composition, intracellular assembly, and biological functions of organic matrices. Here we have performed structural and functional analyses of the organic microrings and organic microplates from T. pseudonana. Proteomics analysis yielded seven proteins of unknown function (termed SiMat proteins) together with five known silica biomineralization proteins (four cingulins and one silaffin). The location of SiMat1-GFP in the insoluble organic microrings and the similarity of tyrosine- and lysine-rich functional domains identifies this protein as a new member of the cingulin protein family. Mass spectrometric analysis indicates that most of the lysine residues of cingulins and the other insoluble organic matrix proteins are post-translationally modified by short polyamine groups, which are known to enhance the silica formation activity of proteins. Studies with recombinant cingulins (rCinY2 and rCinW2) demonstrate that acidic conditions (pH 5.5) trigger the assembly of mixed cingulin aggregates that have silica formation activity. Our results suggest an important role for cingulins in the biogenesis of organic microrings and support the hypothesis that this type of insoluble organic matrix functions in biosilica morphogenesis. PMID:26710847

First Molecular Dynamics simulation insight into the mechanism of organics adsorption from aqueous solutions on microporous carbons

NASA Astrophysics Data System (ADS)

Terzyk, Artur P.; Gauden, Piotr A.; Zieliński, Wojciech; Furmaniak, Sylwester; Wesołowski, Radosław P.; Klimek, Kamil K.

2011-10-01

The results of 84 MD simulations showing the influence of porosity and carbon surface oxidation on adsorption of three organic compounds from aqueous solutions on carbons are reported. Based on a model of 'soft' activated carbon, three carbon structures with gradually changed microporosity were created. Next, different number of surface oxygen groups was introduced. We observe quantitative agreement between simulation and experiment i.e. the decrease in adsorption from benzene down to paracetamol. Simulation results clearly demonstrate that the balance between porosity and carbon surface chemical composition in organics adsorption on carbons, and the pore blocking determine adsorption properties of carbons.

A MODEL FOR ESTIMATING THE INCIDENCE OF SWIMMING-RELATED GASROINTESTINAL ILLNESS AS A FUNCTION OF WATER QUALITY INDICATORS

EPA Science Inventory

Several studies have demonstrated association between gastrointestinal illness (GI) in swimmers and sewage pollution as measured by the density of indicator organisms, such as e. coli and enterococci, in recreational waters. These studies generally classify illnesses into two ca...

The Pentagonal E-Portfolio Model for Selecting, Adopting, Building, and Implementing an E-Portfolio

ERIC Educational Resources Information Center

Buzzetto-More, Nicole; Alade, Ayodele

2008-01-01

Electronic portfolios are a student-centered outcomes-based assessment regime involving learners in the gathering, selection, and organization of artifacts synthesized into a compilation purposed to demonstrate knowledge, skills, and/or achievements supported by reflections that articulate the relevance, credibility, and meaning of the artifacts…

Bridging the Performance Gap with Ergonomics: A Case Study

ERIC Educational Resources Information Center

Rethaber, James D.

2011-01-01

Faced with increased incidences of work-related strain and sprain injuries and OSHA-recordable injuries, the organization in this case study details how it resolved these performance-related issues. This case study also demonstrates the effectiveness of Thomas Gilbert's (1978) Behavior Engineering Model as a tool for analyzing, defining, and…

Rat Models of Cardiovascular Disease Demonstrate Distinctive Pulmonary Gene Expressions for Vascular Response Genes: Impact of Ozone Exposure

EPA Science Inventory

Comparative gene expression profiling of multiple tissues from rat strains with genetic predisposition to diverse cardiovascular diseases (CVD) can help decode the transcriptional program that governs organ-specific functions. We examined expressions of CVD genes in the lungs of ...

Prebiotic Synthesis of Autocatalytic Products From Formaldehyde-Derived Sugars as the Carbon and Energy Source

NASA Technical Reports Server (NTRS)

Weber, Arthur L.

2003-01-01

Our research objective is to understand and model the chemical processes on the primitive Earth that generated the first autocatalytic molecules and microstructures involved in the origin of life. Our approach involves: (a) investigation of a model origin-of-life process named the Sugar Model that is based on the reaction of formaldehyde- derived sugars (trioses and tetroses) with ammonia, and (b) elucidation of the constraints imposed on the chemistry of the origin of life by the fixed energies and rates of C,H,O-organic reactions under mild aqueous conditions. Recently, we demonstrated that under mild aqueous conditions the Sugar Model process yields autocatalytic products, and generates organic micropherules (2-20 micron dia.) that exhibit budding, size uniformity, and chain formation. We also discovered that the sugar substrates of the Sugar Model are capable of reducing nitrite to ammonia under mild aqueous conditions. In addition studies done in collaboration with Sandra Pizzarrello (Arizona State University) revealed that chiral amino acids (including meteoritic isovaline) catalyze both the synthesis and specific handedness of chiral sugars. Our systematic survey of the energies and rates of reactions of C,H,O-organic substrates under mild aqueous conditions revealed several general principles (rules) that govern the direction and rate of organic reactions. These reactivity principles constrain the structure of chemical pathways used in the origin of life, and in modern and primitive metabolism.

Trans-species learning of cellular signaling systems with bimodal deep belief networks

PubMed Central

Chen, Lujia; Cai, Chunhui; Chen, Vicky; Lu, Xinghua

2015-01-01

Motivation: Model organisms play critical roles in biomedical research of human diseases and drug development. An imperative task is to translate information/knowledge acquired from model organisms to humans. In this study, we address a trans-species learning problem: predicting human cell responses to diverse stimuli, based on the responses of rat cells treated with the same stimuli. Results: We hypothesized that rat and human cells share a common signal-encoding mechanism but employ different proteins to transmit signals, and we developed a bimodal deep belief network and a semi-restricted bimodal deep belief network to represent the common encoding mechanism and perform trans-species learning. These ‘deep learning’ models include hierarchically organized latent variables capable of capturing the statistical structures in the observed proteomic data in a distributed fashion. The results show that the models significantly outperform two current state-of-the-art classification algorithms. Our study demonstrated the potential of using deep hierarchical models to simulate cellular signaling systems. Availability and implementation: The software is available at the following URL: http://pubreview.dbmi.pitt.edu/TransSpeciesDeepLearning/. The data are available through SBV IMPROVER website, https://www.sbvimprover.com/challenge-2/overview, upon publication of the report by the organizers. Contact: xinghua@pitt.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:25995230

Trans-species learning of cellular signaling systems with bimodal deep belief networks.

PubMed

Chen, Lujia; Cai, Chunhui; Chen, Vicky; Lu, Xinghua

2015-09-15

Model organisms play critical roles in biomedical research of human diseases and drug development. An imperative task is to translate information/knowledge acquired from model organisms to humans. In this study, we address a trans-species learning problem: predicting human cell responses to diverse stimuli, based on the responses of rat cells treated with the same stimuli. We hypothesized that rat and human cells share a common signal-encoding mechanism but employ different proteins to transmit signals, and we developed a bimodal deep belief network and a semi-restricted bimodal deep belief network to represent the common encoding mechanism and perform trans-species learning. These 'deep learning' models include hierarchically organized latent variables capable of capturing the statistical structures in the observed proteomic data in a distributed fashion. The results show that the models significantly outperform two current state-of-the-art classification algorithms. Our study demonstrated the potential of using deep hierarchical models to simulate cellular signaling systems. The software is available at the following URL: http://pubreview.dbmi.pitt.edu/TransSpeciesDeepLearning/. The data are available through SBV IMPROVER website, https://www.sbvimprover.com/challenge-2/overview, upon publication of the report by the organizers. xinghua@pitt.edu Supplementary data are available at Bioinformatics online. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Modeling the Self-organized Critical Behavior of Earth's Plasma Sheet Reconnection Dynamics

NASA Technical Reports Server (NTRS)

Klimas, Alexander J.

2006-01-01

Analyses of Polar UVI auroral image data show that bright night-side high-latitude W emissions exhibit so many of the key properties of systems in self-organized criticality that an alternate interpretation has become virtually impossible. These analyses will be reviewed. It is now necessary to find and model the source of this behavior. We note that the most common models of self-organized criticality are numerical sandpiles. These are, at root, models that govern the transport of some quantity from a region where it is loaded to another where it is unloaded. Transport is enabled by the excitation of a local threshold instability; it is intermittent and bursty, and it exhibits a number of scale-free statistical properties. Searching for a system in the magnetosphere that is analogous and that, in addition, is known to produce auroral signatures, we focus on the reconnection dynamics of the magnetotail plasma sheet. In our previous work, a driven reconnection model has been constructed and has been under study. The transport of electromagnetic (primarily magnetic) energy carried by the Poynting flux into the reconnection region of the model has been examined. All of the analysis techniques (and more) that have been applied to the auroral image data have also been applied to this Poynting flux. New results will be presented showing that this model also exhibits so many of the key properties of systems in self-organized criticality that an alternate interpretation is implausible. A strong correlation between these key properties of the model and those of the auroral UV emissions will be demonstrated. We suggest that, in general, the driven reconnection model is an important step toward a realistic plasma physical model of self-organized criticality and we conclude, more specifically, that it is also a step in the right direction toward modeling the multiscale reconnection dynamics of the magnetotail.

A Nationwide Survey of Patient Centered Medical Home Demonstration Projects

PubMed Central

Bitton, Asaf; Martin, Carina

2010-01-01

Background The patient centered medical home has received considerable attention as a potential way to improve primary care quality and limit cost growth. Little information exists that systematically compares PCMH pilot projects across the country. Design Cross-sectional key-informant interviews. Participants Leaders from existing PCMH demonstration projects with external payment reform. Measurements We used a semi-structured interview tool with the following domains: project history, organization and participants, practice requirements and selection process, medical home recognition, payment structure, practice transformation, and evaluation design. Results A total of 26 demonstrations in 18 states were interviewed. Current demonstrations include over 14,000 physicians caring for nearly 5 million patients. A majority of demonstrations are single payer, and most utilize a three component payment model (traditional fee for service, per person per month fixed payments, and bonus performance payments). The median incremental revenue per physician per year was $22,834 (range $720 to $91,146). Two major practice transformation models were identified—consultative and implementation of the chronic care model. A majority of demonstrations did not have well-developed evaluation plans. Conclusion Current PCMH demonstration projects with external payment reform include large numbers of patients and physicians as well as a wide spectrum of implementation models. Key questions exist around the adequacy of current payment mechanisms and evaluation plans as public and policy interest in the PCMH model grows. Electronic supplementary material The online version of this article (doi:10.1007/s11606-010-1262-8) contains supplementary material, which is available to authorized users. PMID:20467907

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Chung S., E-mail: csyang@rci.rutgers.edu; Lambert, Joshua D.; Ju Jihyeung

Tea made from the leaves of the plant Camellia sinensis is a popular beverage. The possible cancer-preventive activity of tea and tea polyphenols has been studied extensively. This article briefly reviews studies in animal models, cell lines, and possible relevance of these studies to the prevention of human cancer. The cancer-preventive activity of tea constituents have been demonstrated in many animal models including cancer of the skin, lung, oral cavity, esophagus, stomach, liver, pancreas, small intestine, colon, bladder, prostate, and mammary gland. The major active constituents are polyphenols, of which (-)-epigallocatechin-3-gallate (EGCG) is most abundant, most active, and most studied,more » and caffeine. The molecular mechanisms of the cancer-preventive action, however, are just beginning to be understood. Studies in cell lines led to the proposal of many mechanisms on the action of EGCG. However, mechanisms based on studies with very high concentrations of EGCG may not be relevant to cancer prevention in vivo. The autooxidation of EGCG in cell culture may also produce activities that do not occur in many internal organs. In contrast to the cancer prevention activity demonstrated in different animal models, no such conclusion can be convincingly drawn from epidemiological studies on tea consumption and human cancers. Even though the human data are inconclusive, tea constituents may still be used for the prevention of cancer at selected organ sites if sufficient concentrations of the agent can be delivered to these organs. Some interesting examples in this area are discussed.« less

ForCent model development and testing using the Enriched Background Isotope Study experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parton, W.J.; Hanson, P. J.; Swanston, C.

The ForCent forest ecosystem model was developed by making major revisions to the DayCent model including: (1) adding a humus organic pool, (2) incorporating a detailed root growth model, and (3) including plant phenological growth patterns. Observed plant production and soil respiration data from 1993 to 2000 were used to demonstrate that the ForCent model could accurately simulate ecosystem carbon dynamics for the Oak Ridge National Laboratory deciduous forest. A comparison of ForCent versus observed soil pool {sup 14}C signature ({Delta} {sup 14}C) data from the Enriched Background Isotope Study {sup 14}C experiment (1999-2006) shows that the model correctly simulatesmore » the temporal dynamics of the {sup 14}C label as it moved from the surface litter and roots into the mineral soil organic matter pools. ForCent model validation was performed by comparing the observed Enriched Background Isotope Study experimental data with simulated live and dead root biomass {Delta} {sup 14}C data, and with soil respiration {Delta} {sup 14}C (mineral soil, humus layer, leaf litter layer, and total soil respiration) data. Results show that the model correctly simulates the impact of the Enriched Background Isotope Study {sup 14}C experimental treatments on soil respiration {Delta} {sup 14}C values for the different soil organic matter pools. Model results suggest that a two-pool root growth model correctly represents root carbon dynamics and inputs to the soil. The model fitting process and sensitivity analysis exposed uncertainty in our estimates of the fraction of mineral soil in the slow and passive pools, dissolved organic carbon flux out of the litter layer into the mineral soil, and mixing of the humus layer into the mineral soil layer.« less

ForCent Model Development and Testing using the Enriched Background Isotope Study (EBIS) Experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parton, William; Hanson, Paul J; Swanston, Chris

The ForCent forest ecosystem model was developed by making major revisions to the DayCent model including: (1) adding a humus organic pool, (2) incorporating a detailed root growth model, and (3) including plant phenological growth patterns. Observed plant production and soil respiration data from 1993 to 2000 were used to demonstrate that the ForCent model could accurately simulate ecosystem carbon dynamics for the Oak Ridge National Laboratory deciduous forest. A comparison of ForCent versus observed soil pool 14C signature (? 14C) data from the Enriched Background Isotope Study 14C experiment (1999-2006) shows that the model correctly simulates the temporal dynamicsmore » of the 14C label as it moved from the surface litter and roots into the mineral soil organic matter pools. ForCent model validation was performed by comparing the observed Enriched Background Isotope Study experimental data with simulated live and dead root biomass ? 14C data, and with soil respiration ? 14C (mineral soil, humus layer, leaf litter layer, and total soil respiration) data. Results show that the model correctly simulates the impact of the Enriched Background Isotope Study 14C experimental treatments on soil respiration ? 14C values for the different soil organic matter pools. Model results suggest that a two-pool root growth model correctly represents root carbon dynamics and inputs to the soil. The model fitting process and sensitivity analysis exposed uncertainty in our estimates of the fraction of mineral soil in the slow and passive pools, dissolved organic carbon flux out of the litter layer into the mineral soil, and mixing of the humus layer into the mineral soil layer.« less

A spin exchange model for singlet fission

NASA Astrophysics Data System (ADS)

Yago, Tomoaki; Wakasa, Masanobu

2018-03-01

Singlet fission has been analyzed with the Dexter model in which electron exchange occurs between chromophores, conserving the spin for each electron. In the present study, we propose a spin exchange model for singlet fission. In the spin exchange model, spins are exchanged by the exchange interaction between two electrons. Our analysis with simple spin functions demonstrates that singlet fission is possible by spin exchange. A necessary condition for spin exchange is a variation in exchange interactions. We also adapt the spin exchange model to triplet fusion and triplet energy transfer, which often occur after singlet fission in organic solids.

A recursive vesicle-based model protocell with a primitive model cell cycle

PubMed Central

Kurihara, Kensuke; Okura, Yusaku; Matsuo, Muneyuki; Toyota, Taro; Suzuki, Kentaro; Sugawara, Tadashi

2015-01-01

Self-organized lipid structures (protocells) have been proposed as an intermediate between nonliving material and cellular life. Synthetic production of model protocells can demonstrate the potential processes by which living cells first arose. While we have previously described a giant vesicle (GV)-based model protocell in which amplification of DNA was linked to self-reproduction, the ability of a protocell to recursively self-proliferate for multiple generations has not been demonstrated. Here we show that newborn daughter GVs can be restored to the status of their parental GVs by pH-induced vesicular fusion of daughter GVs with conveyer GVs filled with depleted substrates. We describe a primitive model cell cycle comprising four discrete phases (ingestion, replication, maturity and division), each of which is selectively activated by a specific external stimulus. The production of recursive self-proliferating model protocells represents a step towards eventual production of model protocells that are able to mimic evolution. PMID:26418735

A fully organic retinal prosthesis restores vision in a rat model of degenerative blindness

NASA Astrophysics Data System (ADS)

Maya-Vetencourt, José Fernando; Ghezzi, Diego; Antognazza, Maria Rosa; Colombo, Elisabetta; Mete, Maurizio; Feyen, Paul; Desii, Andrea; Buschiazzo, Ambra; di Paolo, Mattia; di Marco, Stefano; Ticconi, Flavia; Emionite, Laura; Shmal, Dmytro; Marini, Cecilia; Donelli, Ilaria; Freddi, Giuliano; Maccarone, Rita; Bisti, Silvia; Sambuceti, Gianmario; Pertile, Grazia; Lanzani, Guglielmo; Benfenati, Fabio

2017-06-01

The degeneration of photoreceptors in the retina is one of the major causes of adult blindness in humans. Unfortunately, no effective clinical treatments exist for the majority of retinal degenerative disorders. Here we report on the fabrication and functional validation of a fully organic prosthesis for long-term in vivo subretinal implantation in the eye of Royal College of Surgeons rats, a widely recognized model of retinitis pigmentosa. Electrophysiological and behavioural analyses reveal a prosthesis-dependent recovery of light sensitivity and visual acuity that persists up to 6-10 months after surgery. The rescue of the visual function is accompanied by an increase in the basal metabolic activity of the primary visual cortex, as demonstrated by positron emission tomography imaging. Our results highlight the possibility of developing a new generation of fully organic, highly biocompatible and functionally autonomous photovoltaic prostheses for subretinal implants to treat degenerative blindness.

Influence of vapor wall loss in laboratory chambers on yields of secondary organic aerosol

PubMed Central

Zhang, Xuan; Cappa, Christopher D.; Jathar, Shantanu H.; McVay, Renee C.; Ensberg, Joseph J.; Kleeman, Michael J.; Seinfeld, John H.

2014-01-01

Secondary organic aerosol (SOA) constitutes a major fraction of submicrometer atmospheric particulate matter. Quantitative simulation of SOA within air-quality and climate models—and its resulting impacts—depends on the translation of SOA formation observed in laboratory chambers into robust parameterizations. Worldwide data have been accumulating indicating that model predictions of SOA are substantially lower than ambient observations. Although possible explanations for this mismatch have been advanced, none has addressed the laboratory chamber data themselves. Losses of particles to the walls of chambers are routinely accounted for, but there has been little evaluation of the effects on SOA formation of losses of semivolatile vapors to chamber walls. Here, we experimentally demonstrate that such vapor losses can lead to substantially underestimated SOA formation, by factors as much as 4. Accounting for such losses has the clear potential to bring model predictions and observations of organic aerosol levels into much closer agreement. PMID:24711404

Chern Insulator Phase in a Lattice of an Organic Dirac Semimetal with Intracellular Potential and Magnetic Modulations

NASA Astrophysics Data System (ADS)

Osada, Toshihito

2017-12-01

We demonstrate that a Chern insulator can be realized on an actual two-dimensional lattice of an organic Dirac semimetal, α-(BEDT-TTF)2I3, by introducing potential and magnetic modulations in a unit cell. It is a topologically-nontrivial insulator that exhibits the quantum Hall effect even at zero magnetic field. We assume a pattern of site potential and staggered plaquette magnetic flux on the lattice to imitate the observed stripe charge ordering pattern. When magnetic modulation is sufficiently large, the system becomes a Chern insulator, where the Berry curvatures around two gapped Dirac cones have the same sign on each band, and one chiral edge state connects the conduction and valence bands at each crystal edge. The present model is an organic version of Haldane's model, which discusses the Chern insulator on a honeycomb lattice with second nearest neighbor couplings.

Carrier mobility in organic field-effect transistors

NASA Astrophysics Data System (ADS)

Xu, Yong; Benwadih, Mohamed; Gwoziecki, Romain; Coppard, Romain; Minari, Takeo; Liu, Chuan; Tsukagoshi, Kazuhito; Chroboczek, Jan; Balestra, Francis; Ghibaudo, Gerard

2011-11-01

A study of carrier transport in top-gate and bottom-contact TIPS-pentacene organic field-effect transistors (OFETs) based on mobility is presented. Among three mobilities extracted by different methods, the low-field mobility obtained by the Y function exhibits the best reliability and ease for use, whereas the widely applied field-effect mobility is not reliable, particularly in short-channel transistors and at low temperatures. A detailed study of contact transport reveals its strong impact on short-channel transistors, suggesting that a more intrinsic transport analysis is better implemented in relatively longer-channel devices. The observed temperature dependences of mobility are well explained by a transport model with Gaussian-like diffusivity band tails, different from diffusion in localized states band tails. This model explicitly interprets the non-zero constant mobility at low temperatures and clearly demonstrates the effects of disorder and hopping transport on temperature and carrier density dependences of mobility in organic transistors.

A fully organic retinal prosthesis restores vision in a rat model of degenerative blindness

PubMed Central

Antognazza, Maria Rosa; Colombo, Elisabetta; Mete, Maurizio; Feyen, Paul; Desii, Andrea; Buschiazzo, Ambra; Di Paolo, Mattia; Di Marco, Stefano; Ticconi, Flavia; Emionite, Laura; Shmal, Dmytro; Marini, Cecilia; Donelli, Ilaria; Freddi, Giuliano; Maccarone, Rita; Bisti, Silvia; Sambuceti, Gianmario; Pertile, Grazia; Lanzani, Guglielmo; Benfenati, Fabio

2017-01-01

The degeneration of photoreceptors in the retina is one of the major causes of adult blindness in humans. Unfortunately, no effective clinical treatments exist for the majority of retinal degenerative disorders. Here we report on the fabrication and functional validation of a fully organic prosthesis for long-term in vivo subretinal implantation in the eye of Royal College of Surgeons rats, a widely recognized model of Retinitis pigmentosa. Electrophysiological and behavioral analyses reveal a prosthesis-dependent recovery of light-sensitivity and visual acuity that persists up to 6-10 months after surgery. The rescue of the visual function is accompanied by an increase in the basal metabolic activity of the primary visual cortex, as demonstrated by positron emission tomography imaging. Our results highlight the possibility of developing a new generation of fully organic, highly biocompatible and functionally autonomous photovoltaic prostheses for subretinal implants to treat degenerative blindness. PMID:28250420

II. Model building: an electrical theory of control of growth and development in animals, prompted by studies of exogenous magnetic field effects (paper I), and evidence of DNA current conduction, in vitro.

PubMed

Elson, Edward

2009-01-01

A theory of control of cellular proliferation and differentiation in the early development of metazoan systems, postulating a system of electrical controls "parallel" to the processes of molecular biochemistry, is presented. It is argued that the processes of molecular biochemistry alone cannot explain how a developing organism defies a stochastic universe. The demonstration of current flow (charge transfer) along the long axis of DNA through the base-pairs (the "pi-way) in vitro raises the question of whether nature may employ such current flows for biological purposes. Such currents might be too small to be accessible to direct measurement in vivo but conduction has been measured in vitro, and the methods might well be extended to living systems. This has not been done because there is no reasonable model which could stimulate experimentation. We suggest several related, but detachable or independent, models for the biological utility of charge transfer, whose scope admittedly outruns current concepts of thinking about organization, growth, and development in eukaryotic, metazoan systems. The ideas are related to explanations proposed to explain the effects demonstrated on tumors and normal tissues described in Article I (this issue). Microscopic and mesoscopic potential fields and currents are well known at sub-cellular, cellular, and organ systems levels. Not only are such phenomena associated with internal cellular membranes in bioenergetics and information flow, but remarkable long-range fields over tissue interfaces and organs appear to play a role in embryonic development (Nuccitelli, 1992 ). The origin of the fields remains unclear and is the subject of active investigation. We are proposing that similar processes could play a vital role at a "sub-microscopic level," at the level of the chromosomes themselves, and could play a role in organizing and directing fundamental processes of growth and development, in parallel with the more discernible fields and currents described.

DEVELOPMENT OF A SET OF MESH-BASED AND AGE-DEPENDENT CHINESE PHANTOMS AND APPLICATION FOR CT DOSE CALCULATIONS.

PubMed

Pi, Yifei; Liu, Tianyu; Xu, X George

2018-06-01

Phantoms for organ dose calculations are essential in radiation protection dosimetry. This article describes the development of a set of mesh-based and age-dependent phantoms for Chinese populations using reference data recommended by the Chinese government and by the International Atomic Energy Agency (IAEA). Existing mesh-based RPI adult male (RPI-AM) and RPI adult female (RPI-AF) phantoms were deformed to form new phantoms according to anatomical data for the height and weight of Chinese individuals of 5 years old male, 5 years old female, 10 years old male, 10 years old female,15 years old male, 15 years old female, adult male and adult female-named USTC-5 M, USTC-5F, USTC-10M, USTC-10F, USTC-15M, USTC-15F, USTC-AM and USTC-AF, respectively. Following procedures to ensure the accuracy, more than 120 organs/tissues in each model were adjusted to match the Chinese reference parameters and the mass errors were within 0.5%. To demonstrate the usefulness, these new set of phantoms were combined with a fully validated model of the GE LightSpeed Pro 16 multi-detector computed tomography (MDCT) scanner and the GPU-based ARCHER Monte Carlo code to compute organ doses from CT examinations. Organ doses for adult models were then compared with the data of RPI-AM and RPI-AF under the same conditions. The absorbed doses and the effective doses of RPI phantoms are found to be lower than these of the USTC adult phantoms whose body sizes are smaller. Comparisons for the doses among different ages and genders were also made. It was found that teenagers receive more radiation doses than adults do. Such Chinese-specific phantoms are clearly better suited in organ dose studies for the Chinese individuals than phantoms designed for western populations. As already demonstrated, data derived from age-specific Chinese phantoms can help CT operators and designers to optimize image quality and doses.

Real-time method for motion-compensated MR thermometry and MRgHIFU treatment in abdominal organs.

PubMed

Celicanin, Zarko; Auboiroux, Vincent; Bieri, Oliver; Petrusca, Lorena; Santini, Francesco; Viallon, Magalie; Scheffler, Klaus; Salomir, Rares

2014-10-01

Magnetic resonance-guided high-intensity focused ultrasound is considered to be a promising treatment for localized cancer in abdominal organs such as liver, pancreas, or kidney. Abdominal motion, anatomical arrangement, and required sustained sonication are the main challenges. MR acquisition consisted of thermometry performed with segmented gradient-recalled echo echo-planar imaging, and a segment-based one-dimensional MR navigator parallel to the main axis of motion to track the organ motion. This tracking information was used in real-time for: (i) prospective motion correction of MR thermometry and (ii) HIFU focal point position lock-on target. Ex vivo experiments were performed on a sheep liver and a turkey pectoral muscle using a motion demonstrator, while in vivo experiments were conducted on two sheep liver. Prospective motion correction of MR thermometry yielded good signal-to-noise ratio (range, 25 to 35) and low geometric distortion due to the use of segmented EPI. HIFU focal point lock-on target yielded isotropic in-plane thermal build-up. The feasibility of in vivo intercostal liver treatment was demonstrated in sheep. The presented method demonstrated in moving phantoms and breathing sheep accurate motion-compensated MR thermometry and precise HIFU focal point lock-on target using only real-time pencil-beam navigator tracking information, making it applicable without any pretreatment data acquisition or organ motion modeling. Copyright © 2013 Wiley Periodicals, Inc.

Sociolinguistic variables and cognition.

PubMed

Thomas, Erik R

2011-11-01

Sociolinguistics has examined mental organization of language only sporadically. Meanwhile, areas of linguistics that deal with cognitive organization seldom delve deeply into language variation. Variation is essential for understanding how language is structured cognitively, however. Three kinds of evidence are discussed to illustrate this point. First, style shifting demonstrates that language users develop detailed associations of when to produce specific linguistic forms, depending on the pragmatic context. Second, variation in fine-grained phonetic cues shows that cognitive organization applies to linguistic forms not otherwise known to be under speakers' control. Finally, experiments on dialect comprehension and identification demonstrate that listeners have detailed cognitive associations of language variants with groups of people, whether or not they can produce the same variants themselves. A model is presented for how sociolinguistic knowledge can be viewed in relation to other parts of language with regard to cognitive and neural representations. WIREs Cogni Sci 2011 2 701-716 DOI: 10.1002/wcs.152 For further resources related to this article, please visit the WIREs website. Copyright © 2011 John Wiley & Sons, Ltd.

MicroCT-based phenomics in the zebrafish skeleton reveals virtues of deep phenotyping in a distributed organ system.

PubMed

Hur, Matthew; Gistelinck, Charlotte A; Huber, Philippe; Lee, Jane; Thompson, Marjorie H; Monstad-Rios, Adrian T; Watson, Claire J; McMenamin, Sarah K; Willaert, Andy; Parichy, David M; Coucke, Paul; Kwon, Ronald Y

2017-09-08

Phenomics, which ideally involves in-depth phenotyping at the whole-organism scale, may enhance our functional understanding of genetic variation. Here, we demonstrate methods to profile hundreds of phenotypic measures comprised of morphological and densitometric traits at a large number of sites within the axial skeleton of adult zebrafish. We show the potential for vertebral patterns to confer heightened sensitivity, with similar specificity, in discriminating mutant populations compared to analyzing individual vertebrae in isolation. We identify phenotypes associated with human brittle bone disease and thyroid stimulating hormone receptor hyperactivity. Finally, we develop allometric models and show their potential to aid in the discrimination of mutant phenotypes masked by alterations in growth. Our studies demonstrate virtues of deep phenotyping in a spatially distributed organ system. Analyzing phenotypic patterns may increase productivity in genetic screens, and facilitate the study of genetic variants associated with smaller effect sizes, such as those that underlie complex diseases.

Probing nanofriction and Aubry-type signatures in a finite self-organized system

PubMed Central

Kiethe, J.; Nigmatullin, R.; Kalincev, D.; Schmirander, T.; Mehlstäubler, T. E.

2017-01-01

Friction in ordered atomistic layers plays a central role in various nanoscale systems ranging from nanomachines to biological systems. It governs transport properties, wear and dissipation. Defects and incommensurate lattice constants markedly change these properties. Recently, experimental systems have become accessible to probe the dynamics of nanofriction. Here, we present a model system consisting of laser-cooled ions in which nanofriction and transport processes in self-organized systems with back action can be studied with atomic resolution. We show that in a system with local defects resulting in incommensurate layers, there is a transition from sticking to sliding with Aubry-type signatures. We demonstrate spectroscopic measurements of the soft vibrational mode driving this transition and a measurement of the order parameter. We show numerically that both exhibit critical scaling near the transition point. Our studies demonstrate a simple, well-controlled system in which friction in self-organized structures can be studied from classical- to quantum-regimes. PMID:28504271

Hyperspectral imaging of water quality - past applications and future directions.

NASA Astrophysics Data System (ADS)

Ross, M. R. V.; Pavelsky, T.

2017-12-01

Inland waters control the delivery of sediment, carbon, and nutrients from land to ocean by transforming, depositing, and transporting constituents downstream. However, the dominant in situ conditions that control these processes are poorly constrained, especially at larger spatial scales. Hyperspectral imaging, a remote sensing technique that uses reflectance in hundreds of narrow spectral bands, can be used to estimate water quality parameters like sediment and carbon concentration over larger water bodies. Here, we review methods and applications for using hyperspectral imagery to generate near-surface two-dimensional models of water quality in lakes and rivers. Further, we show applications using newly available data from the National Ecological Observation Network aerial observation platform in the Black Warrior and Tombigbee Rivers, Alabama. We demonstrate large spatial variation in chlorophyll, colored dissolved organic matter, and turbidity in each river and uneven mixing of water quality constituents for several kilometers. Finally, we demonstrate some novel techniques using hyperspectral imagery to deconvolve dissolved organic matter spectral signatures to specific organic matter components.

Caprylic and Polygalacturonic Acid Combinations for Eradication of Microbial Organisms Embedded in Biofilm

PubMed Central

Rosenblatt, Joel; Reitzel, Ruth A.; Vargas-Cruz, Nylev; Chaftari, Anne-Marie; Hachem, Ray; Raad, Issam

2017-01-01

There is a need for non-antibiotic, antimicrobial compositions with low toxicity capable of broad-spectrum eradication of pathogenic biofilms in food preparation and healthcare settings. In this study we demonstrated complete biofilm eradication within 60 min with synergistic combinations of caprylic and polygalacturonic (PG) acids in an in vitro biofilm eradication model against representative hospital and foodborne infectious pathogen biofilms (methicillin-resistant Staphylococcus aureus, multidrug-resistant Pseudomonas aeruginosa, Candida albicans, Escherichia coli, and Salmonella enteritidis). Antimicrobial synergy against biofilms was demonstrated by quantifying viable organisms remaining in biofilms exposed to caprylic acid alone, PG acid alone, or combinations of the two. The combinations also synergistically inhibited growth of planktonic organisms. Toxicity of the combination was assessed in vitro on L929 fibroblasts incubated with extracts of caprylic and PG acid combinations using the Alamar Blue metabolic activity assay and the Trypan Blue exclusion cell viability assay. The extracts did not produce cytotoxic responses relative to untreated control fibroblasts. PMID:29093703

Simple mechanisms of early life - simulation model on the origin of semi-cells.

PubMed

Klein, Adrian; Bock, Martin; Alt, Wolfgang

2017-01-01

The development of first cellular structures played an important role in the early evolution of life. Early evolution of life probably took place on a molecular level in a reactive environment. The iron-sulfur theory postulates the formation of cell-like structures on catalytic surfaces. Experiments show that H 2 S together with FeS and other metallic centers drive auto-catalytic surface reactions, in which organic molecules such as pyruvic and amino acids occur. It is questionable which mechanisms are needed to form cell-like structures under these conditions. To address this question, we implemented a model system featuring the fundamentals of molecular dynamics: heat, attraction, repulsion and formation of covalent bonds. Our basic model exhibits a series of essential processes: self-organization of lipid micelles and bilayers, formation of fluid filled cavities, flux of molecules along membranes, transport of energized groups towards sinks and whole colonies of cell-like structures on a larger scale. The results demonstrate that only a few features are sufficient for discovering hitherto non described phenomena of self-assembly and dynamics of cell-like structures as candidates for early evolving proto-cells. Significance statement The quest for a possible origin of life continues to be one of the most fascinating problems in biology. In one theoretical scenario, early life originated from a solution of reactive chemicals in the ancient deep sea, similar to conditions as to be found in thermal vents. Experiments have shown that a variety of organic molecules, the building blocks of life, form under these conditions. Based on such experiments, the iron-sulfur theory postulates the growth of cell-like structures at certain catalytic surfaces. For an explanation and proof of such a process we have developed a computer model simulating molecular assembly of lipid bilayers and formation of semi-cell cavities. The results demonstrate the possibility of cell-like self-organization under appropriate physico-chemical conditions. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Spatially organizing biochemistry: choosing a strategy to translate synthetic biology to the factory.

PubMed

Jakobson, Christopher M; Tullman-Ercek, Danielle; Mangan, Niall M

2018-05-29

Natural biochemical systems are ubiquitously organized both in space and time. Engineering the spatial organization of biochemistry has emerged as a key theme of synthetic biology, with numerous technologies promising improved biosynthetic pathway performance. One strategy, however, may produce disparate results for different biosynthetic pathways. We use a spatially resolved kinetic model to explore this fundamental design choice in systems and synthetic biology. We predict that two example biosynthetic pathways have distinct optimal organization strategies that vary based on pathway-dependent and cell-extrinsic factors. Moreover, we demonstrate that the optimal design varies as a function of kinetic and biophysical properties, as well as culture conditions. Our results suggest that organizing biosynthesis has the potential to substantially improve performance, but that choosing the appropriate strategy is key. The flexible design-space analysis we propose can be adapted to diverse biosynthetic pathways, and lays a foundation to rationally choose organization strategies for biosynthesis.

Self-organization and progenitor targeting generate stable patterns in planarian regeneration.

PubMed

Atabay, Kutay Deniz; LoCascio, Samuel A; de Hoog, Thom; Reddien, Peter W

2018-04-27

During animal regeneration, cells must organize into discrete and functional systems. We show that self-organization, along with patterning cues, govern progenitor behavior in planarian regeneration. Surgical paradigms allowed the manipulation of planarian eye regeneration in predictable locations and numbers, generating alternative stable neuroanatomical states for wild-type animals with multiple functional ectopic eyes. We used animals with multiple ectopic eyes and eye transplantation to demonstrate that broad progenitor specification, combined with self-organization, allows anatomy maintenance during regeneration. We propose a model for regenerative progenitors involving (i) migratory targeting cues, (ii) self-organization into existing or regenerating eyes, and (iii) a broad zone, associated with coarse progenitor specification, in which eyes can be targeted by progenitors. These three properties help explain how tissues can be organized during regeneration. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Deformable torso phantoms of Chinese adults for personalized anatomy modelling.

PubMed

Wang, Hongkai; Sun, Xiaobang; Wu, Tongning; Li, Congsheng; Chen, Zhonghua; Liao, Meiying; Li, Mengci; Yan, Wen; Huang, Hui; Yang, Jia; Tan, Ziyu; Hui, Libo; Liu, Yue; Pan, Hang; Qu, Yue; Chen, Zhaofeng; Tan, Liwen; Yu, Lijuan; Shi, Hongcheng; Huo, Li; Zhang, Yanjun; Tang, Xin; Zhang, Shaoxiang; Liu, Changjian

2018-04-16

In recent years, there has been increasing demand for personalized anatomy modelling for medical and industrial applications, such as ergonomics device development, clinical radiological exposure simulation, biomechanics analysis, and 3D animation character design. In this study, we constructed deformable torso phantoms that can be deformed to match the personal anatomy of Chinese male and female adults. The phantoms were created based on a training set of 79 trunk computed tomography (CT) images (41 males and 38 females) from normal Chinese subjects. Major torso organs were segmented from the CT images, and the statistical shape model (SSM) approach was used to learn the inter-subject anatomical variations. To match the personal anatomy, the phantoms were registered to individual body surface scans or medical images using the active shape model method. The constructed SSM demonstrated anatomical variations in body height, fat quantity, respiratory status, organ geometry, male muscle size, and female breast size. The masses of the deformed phantom organs were consistent with Chinese population organ mass ranges. To validate the performance of personal anatomy modelling, the phantoms were registered to the body surface scan and CT images. The registration accuracy measured from 22 test CT images showed a median Dice coefficient over 0.85, a median volume recovery coefficient (RC vlm ) between 0.85 and 1.1, and a median averaged surface distance (ASD) < 1.5 mm. We hope these phantoms can serve as computational tools for personalized anatomy modelling for the research community. © 2018 Anatomical Society.

A unified model of shoot tropism in plants: photo-, gravi- and Propio-ception.

PubMed

Bastien, Renaud; Douady, Stéphane; Moulia, Bruno

2015-02-01

Land plants rely mainly on gravitropism and phototropism to control their posture and spatial orientation. In natural conditions, these two major tropisms act concurrently to create a photogravitropic equilibrium in the responsive organ. Recently, a parsimonious model was developed that accurately predicted the complete gravitropic and proprioceptive control over the movement of different organs in different species in response to gravitational stimuli. Here we show that the framework of this unifying graviproprioceptive model can be readily extended to include phototropism. The interaction between gravitropism and phototropism results in an alignment of the apical part of the organ toward a photogravitropic set-point angle. This angle is determined by a combination of the two directional stimuli, gravity and light, weighted by the ratio between the gravi- and photo-sensitivities of the plant organ. In the model, two dimensionless numbers, the graviproprioceptive number B and the photograviceptive number M, control the dynamics and the shapes of the movement. The extended model agrees well with two sets of detailed quantitative data on photogravitropic equilibrium in oat coleoptiles. It is demonstrated that the influence of light intensity I can be included in the model in a power-law-dependent relationship M(I). The numbers B and M and the related photograviceptive number D are all quantitative genetic traits that can be measured in a straightforward manner, opening the way to the phenotyping of molecular and mechanical aspects of shoot tropism.

A Unified Model of Shoot Tropism in Plants: Photo-, Gravi- and Propio-ception

PubMed Central

Bastien, Renaud; Douady, Stéphane; Moulia, Bruno

2015-01-01

Land plants rely mainly on gravitropism and phototropism to control their posture and spatial orientation. In natural conditions, these two major tropisms act concurrently to create a photogravitropic equilibrium in the responsive organ. Recently, a parsimonious model was developed that accurately predicted the complete gravitropic and proprioceptive control over the movement of different organs in different species in response to gravitational stimuli. Here we show that the framework of this unifying graviproprioceptive model can be readily extended to include phototropism. The interaction between gravitropism and phototropism results in an alignment of the apical part of the organ toward a photogravitropic set-point angle. This angle is determined by a combination of the two directional stimuli, gravity and light, weighted by the ratio between the gravi- and photo-sensitivities of the plant organ. In the model, two dimensionless numbers, the graviproprioceptive number B and the photograviceptive number M, control the dynamics and the shapes of the movement. The extended model agrees well with two sets of detailed quantitative data on photogravitropic equilibrium in oat coleoptiles. It is demonstrated that the influence of light intensity I can be included in the model in a power-law-dependent relationship M(I). The numbers B and M and the related photograviceptive number D are all quantitative genetic traits that can be measured in a straightforward manner, opening the way to the phenotyping of molecular and mechanical aspects of shoot tropism. PMID:25692607

Study of Adsorption and Desorption Performances of Zr-Based Metal-Organic Frameworks Using Paper Spray Mass Spectrometry.

PubMed

Wang, Xiaoting; Chen, Ying; Zheng, Yajun; Zhang, Zhiping

2017-07-08

The dynamic pore systems and high surface areas of flexible metal-organic framework materials make them excellent candidates to be used in different kinds of adsorption processes. However, the adsorption and desorption behaviors of therapeutic drugs on metal-organic frameworks in solution are not fully developed. Here, we systematically investigated the adsorption and desorption behaviors of a typical therapeutic drug, verapamil, over several Zr-based metal-organic frameworks [e.g., Zr-FUM, UiO-66(Zr), UiO-66(Zr)-NH₂ and UiO-66(Zr)-2COOH] as well as ZrO₂ in an acetonitrile solution by using paper spray mass spectrometry. In contrast to other materials, UiO-66(Zr)-2COOH demonstrated a superior adsorption performance to verapamil due to their strong acid-base and/or hydrogen-bond interactions, and the adsorption process fitted well with the pseudo-second-order kinetic model. As verapamil-adsorbed materials were used for desorption experiments, ZrO₂ demonstrated the most favorable desorption performance, whereas UiO-66(Zr)-2COOH yielded the poorest desorption capability. These Zr-based materials had also been coated at the surface with filter papers for the analysis of various drugs and proteins in the process of paper spray mass spectrometry. The results demonstrated that among the studied materials, ZrO₂-coated paper gave the most favorable desorption performance as a pure drug solution, whereas the paper from UiO-66(Zr) demonstrated the optimal capability in the analyses of therapeutic drugs in a complex matrix (e.g., blood) and a protein (e.g., myoglobin).

TH-CD-202-07: A Methodology for Generating Numerical Phantoms for Radiation Therapy Using Geometric Attribute Distribution Models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dolly, S; Chen, H; Mutic, S

Purpose: A persistent challenge for the quality assessment of radiation therapy treatments (e.g. contouring accuracy) is the absence of the known, ground truth for patient data. Moreover, assessment results are often patient-dependent. Computer simulation studies utilizing numerical phantoms can be performed for quality assessment with a known ground truth. However, previously reported numerical phantoms do not include the statistical properties of inter-patient variations, as their models are based on only one patient. In addition, these models do not incorporate tumor data. In this study, a methodology was developed for generating numerical phantoms which encapsulate the statistical variations of patients withinmore » radiation therapy, including tumors. Methods: Based on previous work in contouring assessment, geometric attribute distribution (GAD) models were employed to model both the deterministic and stochastic properties of individual organs via principle component analysis. Using pre-existing radiation therapy contour data, the GAD models are trained to model the shape and centroid distributions of each organ. Then, organs with different shapes and positions can be generated by assigning statistically sound weights to the GAD model parameters. Organ contour data from 20 retrospective prostate patient cases were manually extracted and utilized to train the GAD models. As a demonstration, computer-simulated CT images of generated numerical phantoms were calculated and assessed subjectively and objectively for realism. Results: A cohort of numerical phantoms of the male human pelvis was generated. CT images were deemed realistic both subjectively and objectively in terms of image noise power spectrum. Conclusion: A methodology has been developed to generate realistic numerical anthropomorphic phantoms using pre-existing radiation therapy data. The GAD models guarantee that generated organs span the statistical distribution of observed radiation therapy patients, according to the training dataset. The methodology enables radiation therapy treatment assessment with multi-modality imaging and a known ground truth, and without patient-dependent bias.« less

Point process models for localization and interdependence of punctate cellular structures.

PubMed

Li, Ying; Majarian, Timothy D; Naik, Armaghan W; Johnson, Gregory R; Murphy, Robert F

2016-07-01

Accurate representations of cellular organization for multiple eukaryotic cell types are required for creating predictive models of dynamic cellular function. To this end, we have previously developed the CellOrganizer platform, an open source system for generative modeling of cellular components from microscopy images. CellOrganizer models capture the inherent heterogeneity in the spatial distribution, size, and quantity of different components among a cell population. Furthermore, CellOrganizer can generate quantitatively realistic synthetic images that reflect the underlying cell population. A current focus of the project is to model the complex, interdependent nature of organelle localization. We built upon previous work on developing multiple non-parametric models of organelles or structures that show punctate patterns. The previous models described the relationships between the subcellular localization of puncta and the positions of cell and nuclear membranes and microtubules. We extend these models to consider the relationship to the endoplasmic reticulum (ER), and to consider the relationship between the positions of different puncta of the same type. Our results do not suggest that the punctate patterns we examined are dependent on ER position or inter- and intra-class proximity. With these results, we built classifiers to update previous assignments of proteins to one of 11 patterns in three distinct cell lines. Our generative models demonstrate the ability to construct statistically accurate representations of puncta localization from simple cellular markers in distinct cell types, capturing the complex phenomena of cellular structure interaction with little human input. This protocol represents a novel approach to vesicular protein annotation, a field that is often neglected in high-throughput microscopy. These results suggest that spatial point process models provide useful insight with respect to the spatial dependence between cellular structures. © 2016 International Society for Advancement of Cytometry. © 2016 International Society for Advancement of Cytometry.

Assessment of genotoxic effects of flumorph by the comet assay in mice organs.

PubMed

Zhang, T; Zhao, Q; Zhang, Y; Ning, J

2014-03-01

The present study investigated the genotoxic effects of flumorph in various organs (brain, liver, spleen, kidney and sperm) of mice. The DNA damage, measured as comet tail length (µm), was determined using the alkaline comet assay. The comet assay is a sensitive assay for the detection of genotoxicity caused by flumorph using mice as a model. Statistically significant increases in comet assay for both dose-dependent and duration-dependent DNA damage were observed in all the organs assessed. The organs exhibited the maximum DNA damage in 96 h at 54 mg/kg body weight. Brain showed maximum DNA damage followed by spleen > kidney > liver > sperm. Our data demonstrated that flumorph had induced systemic genotoxicity in mammals as it caused DNA damage in all tested vital organs, especially in brain and spleen.

Modified kinetic-hydraulic UASB reactor model for treatment of wastewater containing biodegradable organic substrates.

PubMed

El-Seddik, Mostafa M; Galal, Mona M; Radwan, A G; Abdel-Halim, Hisham S

2016-01-01

This paper addresses a modified kinetic-hydraulic model for up-flow anaerobic sludge blanket (UASB) reactor aimed to treat wastewater of biodegradable organic substrates as acetic acid based on Van der Meer model incorporated with biological granules inclusion. This dynamic model illustrates the biomass kinetic reaction rate for both direct and indirect growth of microorganisms coupled with the amount of biogas produced by methanogenic bacteria in bed and blanket zones of reactor. Moreover, the pH value required for substrate degradation at the peak specific growth rate of bacteria is discussed for Andrews' kinetics. The sensitivity analyses of biomass concentration with respect to fraction of volume of reactor occupied by granules and up-flow velocity are also demonstrated. Furthermore, the modified mass balance equations of reactor are applied during steady state using Newton Raphson technique to obtain a suitable degree of freedom for the modified model matching with the measured results of UASB Sanhour wastewater treatment plant in Fayoum, Egypt.

[The implementation of computer model in research of dynamics of proliferation of cells of thyroid gland follicle].

PubMed

Abduvaliev, A A; Gil'dieva, M S; Khidirov, B N; Saĭdalieva, M; Khasanov, A A; Musaeva, Sh N; Saatov, T S

2012-04-01

The article deals with the results of computational experiments in research of dynamics of proliferation of cells of thyroid gland follicle in normal condition and in the case of malignant neoplasm. The model studies demonstrated that the chronic increase of parameter of proliferation of cells of thyroid gland follicle results in abnormal behavior of numbers of cell cenosis of thyroid gland follicle. The stationary state interrupts, the auto-oscillations occur with transition to irregular oscillations with unpredictable cell proliferation and further to the "black hole" effect. It is demonstrated that the present medical biologic experimental data and theory propositions concerning the structural functional organization of thyroid gland on cell level permit to develop mathematical models for quantitative analysis of numbers of cell cenosis of thyroid gland follicle in normal conditions. The technique of modeling of regulative mechanisms of living systems and equations of cell cenosis regulations was used

Religion as a resource for positive youth development: religion, social capital, and moral outcomes.

PubMed

Ebstyne King, Pamela; Furrow, James L

2004-09-01

Although existing literature demonstrates that developmental benefits are associated with religion for adolescents, little is understood about the dynamics of this relationship. Drawing on social capital theory, this study tested a conceptual model exploring socially embedded religious influences on moral outcomes. A three-dimensional model of social capital demonstrated how social interaction, trust, and shared vision enable social ties associated with religiousness to influence moral behavior. Structural equation modeling was used with data gathered from 735 urban youths to test a proposed model of the effects of religiousness on moral outcomes. Results suggested that religiously active youths report higher levels of social capital resources and that the influence of adolescent religiousness on moral outcomes was mediated through social capital resources. Suggestions for further research and implications for faith-based youth development organizations are considered. Copyright 2004 American Psychological Association

Interactions between soil thermal and hydrological dynamics in the response of Alaska ecosystems to fire disturbance

USGS Publications Warehouse

Yi, Shuhua; McGuire, A. David; Harden, Jennifer; Kasischke, Eric; Manies, Kristen L.; Hinzman, Larry; Liljedahl, Anna K.; Randerson, J.; Liu, Heping; Romanovsky, Vladimir E.; Marchenko, Sergey S.; Kim, Yongwon

2009-01-01

Soil temperature and moisture are important factors that control many ecosystem processes. However, interactions between soil thermal and hydrological processes are not adequately understood in cold regions, where the frozen soil, fire disturbance, and soil drainage play important roles in controlling interactions among these processes. These interactions were investigated with a new ecosystem model framework, the dynamic organic soil version of the Terrestrial Ecosystem Model, that incorporates an efficient and stable numerical scheme for simulating soil thermal and hydrological dynamics within soil profiles that contain a live moss horizon, fibrous and amorphous organic horizons, and mineral soil horizons. The performance of the model was evaluated for a tundra burn site that had both preburn and postburn measurements, two black spruce fire chronosequences (representing space-for-time substitutions in well and intermediately drained conditions), and a poorly drained black spruce site. Although space-for-time substitutions present challenges in model-data comparison, the model demonstrates substantial ability in simulating the dynamics of evapotranspiration, soil temperature, active layer depth, soil moisture, and water table depth in response to both climate variability and fire disturbance. Several differences between model simulations and field measurements identified key challenges for evaluating/improving model performance that include (1) proper representation of discrepancies between air temperature and ground surface temperature; (2) minimization of precipitation biases in the driving data sets; (3) improvement of the measurement accuracy of soil moisture in surface organic horizons; and (4) proper specification of organic horizon depth/properties, and soil thermal conductivity.

Decision-making without a brain: how an amoeboid organism solves the two-armed bandit.

PubMed

Reid, Chris R; MacDonald, Hannelore; Mann, Richard P; Marshall, James A R; Latty, Tanya; Garnier, Simon

2016-06-01

Several recent studies hint at shared patterns in decision-making between taxonomically distant organisms, yet few studies demonstrate and dissect mechanisms of decision-making in simpler organisms. We examine decision-making in the unicellular slime mould Physarum polycephalum using a classical decision problem adapted from human and animal decision-making studies: the two-armed bandit problem. This problem has previously only been used to study organisms with brains, yet here we demonstrate that a brainless unicellular organism compares the relative qualities of multiple options, integrates over repeated samplings to perform well in random environments, and combines information on reward frequency and magnitude in order to make correct and adaptive decisions. We extend our inquiry by using Bayesian model selection to determine the most likely algorithm used by the cell when making decisions. We deduce that this algorithm centres around a tendency to exploit environments in proportion to their reward experienced through past sampling. The algorithm is intermediate in computational complexity between simple, reactionary heuristics and calculation-intensive optimal performance algorithms, yet it has very good relative performance. Our study provides insight into ancestral mechanisms of decision-making and suggests that fundamental principles of decision-making, information processing and even cognition are shared among diverse biological systems. © 2016 The Authors.

Disturbances to metal partitioning during toxicity testing of iron(II)-rich estuarine pore waters and whole sediments.

PubMed

Simpson, Stuart L; Batley, Graeme E

2003-02-01

Metal partitioning is altered when suboxic estuarine sediments containing Fe(II)-rich pore waters are disturbed during collection, preparation, and toxicity testing. Experiments with model Fe(II)-rich pore waters demonstrated the rates at which adsorptive losses of Cd, Cu, Ni, Mn, Pb, and Zn occur upon exposure to air. Experiments with Zn-contaminated estuarine sediments demonstrated large and often unpredictable changes to metal partitioning during sediment storage, removal of organisms, and homogenization before testing. Small modifications to conditions, such as aeration of overlying waters, caused large changes to the metal partitioning. Disturbances caused by sediment collection required many weeks for reestablishment of equilibrium. Bioturbation by benthic organisms led to oxidation of pore-water Fe(II) and lower Zn fluxes because of the formation of Fe hydroxide precipitates that adsorb pore-water Zn. For five weeks after the addition of organisms to sediments, Zn fluxes increased slowly as the organisms established themselves in the sediments, indicating that the establishment of equilibrium was not rapid. The results are discussed in terms of the dynamic nature of suboxic, Fe(II)-rich estuarine sediments, how organisms perturb their environment, and the importance of understanding chemistry in toxicity testing with whole sediments or pore water. Recommendations are provided for the handling of sediments for toxicity testing.

In-situ Roll-to-Roll Printing of Highly Efficient Organic Solar Cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bao, Zhenan; Toney, Michael; Clancy, Paulette

2016-05-30

This project focuses on developing a roll-to-roll printing setup for organic solar cells with the capability to follow the film formation in situ with small and wide angle X-ray scattering, and to improve the performance of printed organic solar cells. We demonstrated the use of the printing setup to capture important aspects of existing industrial printing methods, which ensures that the solar cell performance achieved in our printing experiments would be largely retained in an industrial fabrication process. We employed both known and newly synthesized polymers as the donor and acceptor materials, and we studied the morphological changes in realmore » time during the printing process by X-ray scattering. Our experimental efforts are also accompanied by theoretical modeling of both the fluid dynamic aspects of the printing process and the nucleation and crystallization kinetics during the film formation. The combined insight into the printing process gained from the research provides a detailed understanding of the factors governing the printed solar cell’s performance. Finally using the knowledge we gained, we demonstrated large area ( > 10 cm2) printed organic solar cells with more than 5 percent power conversion efficiency, which is best achieved performance for roll-to-roll printed organic solar cells.« less

A new model of sperm nuclear architecture following assessment of the organization of centromeres and telomeres in three-dimensions.

PubMed

Ioannou, Dimitrios; Millan, Nicole M; Jordan, Elizabeth; Tempest, Helen G

2017-01-31

The organization of chromosomes in sperm nuclei has been proposed to possess a unique "hairpin-loop" arrangement, which is hypothesized to aid in the ordered exodus of the paternal genome following fertilization. This study simultaneously assessed the 3D and 2D radial and longitudinal organization of telomeres, centromeres, and investigated whether chromosomes formed the same centromere clusters in sperm cells. Reproducible radial and longitudinal non-random organization was observed for all investigated loci using both 3D and 2D approaches in multiple subjects. We report novel findings, with telomeres and centromeres being localized throughout the nucleus but demonstrating roughly a 1:1 distribution in the nuclear periphery and the intermediate regions with <15% occupying the nuclear interior. Telomeres and centromeres were observed to aggregate in sperm nuclei, forming an average of 20 and 7 clusters, respectively. Reproducible longitudinal organization demonstrated preferential localization of telomeres and centromeres in the mid region of the sperm cell. Preliminary evidence is also provided to support the hypothesis that specific chromosomes preferentially form the same centromere clusters. The more segmental distribution of telomeres and centromeres as described in this study could more readily accommodate and facilitate the sequential exodus of paternal chromosomes following fertilization.

A new model of sperm nuclear architecture following assessment of the organization of centromeres and telomeres in three-dimensions

PubMed Central

Ioannou, Dimitrios; Millan, Nicole M.; Jordan, Elizabeth; Tempest, Helen G.

2017-01-01

The organization of chromosomes in sperm nuclei has been proposed to possess a unique “hairpin-loop” arrangement, which is hypothesized to aid in the ordered exodus of the paternal genome following fertilization. This study simultaneously assessed the 3D and 2D radial and longitudinal organization of telomeres, centromeres, and investigated whether chromosomes formed the same centromere clusters in sperm cells. Reproducible radial and longitudinal non-random organization was observed for all investigated loci using both 3D and 2D approaches in multiple subjects. We report novel findings, with telomeres and centromeres being localized throughout the nucleus but demonstrating roughly a 1:1 distribution in the nuclear periphery and the intermediate regions with <15% occupying the nuclear interior. Telomeres and centromeres were observed to aggregate in sperm nuclei, forming an average of 20 and 7 clusters, respectively. Reproducible longitudinal organization demonstrated preferential localization of telomeres and centromeres in the mid region of the sperm cell. Preliminary evidence is also provided to support the hypothesis that specific chromosomes preferentially form the same centromere clusters. The more segmental distribution of telomeres and centromeres as described in this study could more readily accommodate and facilitate the sequential exodus of paternal chromosomes following fertilization. PMID:28139771

Correlation between Organic Matter Degradation and the Rheological Performance of Waste Sludge During Anaerobic Digestion

NASA Astrophysics Data System (ADS)

Morel, Evangelina S.; Hernández-Hernándes, José A.; Méndez-Contreras, Juan M.; Cantú-Lozano, Denis

2008-07-01

Anaerobic digestion has demonstrated to be a good possibility to reduce the organic matter contents in waste activated sludge resulting in the effluents treatment. An anaerobic digestion was carried out in a 3.5 L reactor at 35 °C for a period of 20 days. An electronic thermostat controlled the temperature. The reactor was agitated at a rate of 200 rpm. The study of the rheological behavior of the waste activated sludge was done with an Anton Paar™ rheometer model MCR301 with a peltier plate for temperature control. Four-blade vane geometry was used with samples of 37 mL for determining rheological properties. Sampling (two samples) was taken every four days of anaerobic digestion through a peristaltic pump. The samples behavior was characterized by the Herschel-Bulkley model, with R2>0.99 for most cases. In all samples were found an apparent viscosity (ηap) and yield stress (τo) decrement when organic matter content diminishes. This demonstrates a relationship between rheological properties and organic matter concentration (% volatile solids). Also the flow activation energy (Ea) was calculated using the Ahrrenius correlation and samples of waste activated sludge before anaerobic digestion. In this case, samples were run in the rheometer at 200 rpm and a temperature range of 25 to 75 °C with an increment rate of 2 °C per minute. The yield stress observed was in a range of 0.93-0.18 Pa, the apparent viscosity was in a range of 0.0358-0.0010 Pa.s, the reduction of organic matter was in a range of 62.57-58.43% volatile solids and the average flow activation energy was 1.71 Calṡg-mol-1.

Unified percolation model for bipolaron-assisted organic magnetoresistance in the unipolar transport regime

NASA Astrophysics Data System (ADS)

Gao, Nan; Li, Ling; Lu, Nianduan; Xie, Changqing; Liu, Ming; Bässler, Heinz

2016-08-01

The fact that in organic semiconductors the Hubbard energy is usually positive appears to be at variance with a bipolaron model to explain magnetoresistance (MR) in those systems. Employing percolation theory, we demonstrate that a moderately positive U is indeed compatible with the bipolaron concept for MR in unipolar current flow, provided that the system is energetically disordered, and the density of states (DOS) distribution is partially filled, so that the Fermi level overlaps with tail states of the DOS. By exploring a broad parameter space, we show that MR becomes maximal around U =0 and even diminishes at large negative values of U because of spin independent bipolaron dissociation. Trapping effects and reduced dimension enhance MR.

Making Education Work for Hispanic Americans: Some Promising Community-Based Practices.

ERIC Educational Resources Information Center

Orum, Lori S.

This paper describes the work of the National Council of La Raza to improve education for Hispanic students and their families. It provides an overview of the council's Innovative Education Project, an effort to demonstrate and evaluate effective models for use by affiliated community-based organizations to improve educational outcomes for…

The Use of "Kryptolebias marmoratus" Eggs as an Educational Tool for Embryology Education

ERIC Educational Resources Information Center

Genade, Tyrone

2016-01-01

Plastic embryological models lack the excitement of seeing real, live embryos. Chick embryos are often used to demonstrate embryological development and blood circulation to students but this necessitates the death of the organism. "Kryptolebias marmoratus" embryos are large and can be viewed by means of a light microscope without need…

LABORATORY-SCALE ANALYSIS OF AQUIFER REMEDIATION BY IN-WELL VAPOR STRIPPING 2. MODELING RESULTS. (R825689C061)

EPA Science Inventory

Abstract

The removal of volatile organic compounds (VOCs) from groundwater through in-well vapor stripping has been demonstrated by Gonen and Gvirtzman (1997, J. Contam. Hydrol., 00: 000-000) at the laboratory scale. The present study compares experimental breakthrough...

Strategic Management in Universities as a Factor of Their Global Competitiveness

ERIC Educational Resources Information Center

Parakhina, Valentina; Godina, Olga; Boris, Olga; Ushvitsky, Lev

2017-01-01

Purpose: Modernization of Russian higher education is carried out with the purpose of its successful integration into the global educational environment. However, the contemporary management model of most Russian universities demonstrates a low efficiency level. The purpose of this paper is to identify the problems of organizing the universities'…

Recruitment dynamics in complex life cycles. [of organisms living in marine rocky zone

NASA Technical Reports Server (NTRS)

Roughgarden, Jonathan; Possingham, Hugh; Gaines, Steven

1988-01-01

Factors affecting marine population fluctuations are discussed with particular attention given to a common barnacle species of the Pacific coast of North America. It is shown how models combining larval circulation with adult interactions can potentially forecast population fluctuations. These findings demonstrate how processes in different ecological habitats are coupled.

Beyond meaningful use: getting meaningful value from IT.

PubMed

Fortin, Jason; Zywiak, Walt

2010-02-01

The HITECH provisions of ARRA include financial incentives for providers to demonstrate meaningful use of certified EHR technology. However, to maximize the value of IT under new payment models, provider organizations will need to go beyond meaningful use criteria in three key areas: Delivering high-quality care. Ensuring coordinated care. Integrating financial systems.

Bibliographic Networks and Microcomputer Applications for Aerospace and Defense Scientific and Technical Information.

ERIC Educational Resources Information Center

Hartt, Richard W.

This report discusses the characteristics, operations, and automation requirements of technical libraries providing services to organizations involved in aerospace and defense scientific and technical work, and describes the Local Automation Model project. This on-going project is designed to demonstrate the concept of a fully integrated library…

Knowledge Transfer among Projects Using a Learn-Forget Model

ERIC Educational Resources Information Center

Tukel, Oya I.; Rom, Walter O.; Kremic, Tibor

2008-01-01

Purpose: The purpose of this paper is to analyze the impact of learning in a project-driven organization and demonstrate analytically how the learning, which takes place during the execution of successive projects, and the forgetting that takes place during the dormant time between the project executions, can impact performance and productivity in…

Beyond clay: Towards an improved set of variables for predicting soil organic matter content

USGS Publications Warehouse

Rasmussen, Craig; Heckman, Katherine; Wieder, William R.; Keiluweit, Marco; Lawrence, Corey R.; Berhe, Asmeret Asefaw; Blankinship, Joseph C.; Crow, Susan E.; Druhan, Jennifer; Hicks Pries, Caitlin E.; Marin-Spiotta, Erika; Plante, Alain F.; Schadel, Christina; Schmiel, Joshua P.; Sierra, Carlos A.; Thompson, Aaron; Wagai, Rota

2018-01-01

Improved quantification of the factors controlling soil organic matter (SOM) stabilization at continental to global scales is needed to inform projections of the largest actively cycling terrestrial carbon pool on Earth, and its response to environmental change. Biogeochemical models rely almost exclusively on clay content to modify rates of SOM turnover and fluxes of climate-active CO2 to the atmosphere. Emerging conceptual understanding, however, suggests other soil physicochemical properties may predict SOM stabilization better than clay content. We addressed this discrepancy by synthesizing data from over 5,500 soil profiles spanning continental scale environmental gradients. Here, we demonstrate that other physicochemical parameters are much stronger predictors of SOM content, with clay content having relatively little explanatory power. We show that exchangeable calcium strongly predicted SOM content in water-limited, alkaline soils, whereas with increasing moisture availability and acidity, iron- and aluminum-oxyhydroxides emerged as better predictors, demonstrating that the relative importance of SOM stabilization mechanisms scales with climate and acidity. These results highlight the urgent need to modify biogeochemical models to better reflect the role of soil physicochemical properties in SOM cycling.

Physical mechanism responsible for the stretched exponential decay behavior of aging organic light-emitting diodes

NASA Astrophysics Data System (ADS)

Féry, C.; Racine, B.; Vaufrey, D.; Doyeux, H.; Cinà, S.

2005-11-01

The main process responsible for the luminance degradation in organic light-emitting diodes (OLEDs) driven under constant current has not yet been identified. In this paper, we propose an approach to describe the intrinsic mechanisms involved in the OLED aging. We first show that a stretched exponential decay can be used to fit almost all the luminance versus time curves obtained under different driving conditions. In this way, we are able to prove that they can all be described by employing a single free parameter model. By using an approach based on local relaxation events, we will demonstrate that a single mechanism is responsible for the dominant aging process. Furthermore, we will demonstrate that the main relaxation event is the annihilation of one emissive center. We then use our model to fit all the experimental data measured under different driving condition, and show that by carefully fitting the accelerated luminance lifetime-curves, we can extrapolate the low-luminance lifetime needed for real display applications, with a high degree of accuracy.

Charting the energy landscape of metal/organic interfaces via machine learning

NASA Astrophysics Data System (ADS)

Scherbela, Michael; Hörmann, Lukas; Jeindl, Andreas; Obersteiner, Veronika; Hofmann, Oliver T.

2018-04-01

The rich polymorphism exhibited by inorganic/organic interfaces is a major challenge for materials design. In this work, we present a method to efficiently explore the potential energy surface and predict the formation energies of polymorphs and defects. This is achieved by training a machine learning model on a list of only 100 candidate structures that are evaluated via dispersion-corrected density functional theory (DFT) calculations. We demonstrate the power of this approach for tetracyanoethylene on Ag(100) and explain the anisotropic ordering that is observed experimentally.

Charting the energy landscape of metal/organic interfaces via machine learning

DOE PAGES

Scherbela, Michael; Hormann, Lukas; Jeindl, Andreas; ...

2018-04-17

The rich polymorphism exhibited by inorganic/organic interfaces is a major challenge for materials design. Here in this work, we present a method to efficiently explore the potential energy surface and predict the formation energies of polymorphs and defects. This is achieved by training a machine learning model on a list of only 100 candidate structures that are evaluated via dispersion-corrected density functional theory (DFT) calculations. Finally, we demonstrate the power of this approach for tetracyanoethylene on Ag(100) and explain the anisotropic ordering that is observed experimentally.

Charting the energy landscape of metal/organic interfaces via machine learning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scherbela, Michael; Hormann, Lukas; Jeindl, Andreas

The rich polymorphism exhibited by inorganic/organic interfaces is a major challenge for materials design. Here in this work, we present a method to efficiently explore the potential energy surface and predict the formation energies of polymorphs and defects. This is achieved by training a machine learning model on a list of only 100 candidate structures that are evaluated via dispersion-corrected density functional theory (DFT) calculations. Finally, we demonstrate the power of this approach for tetracyanoethylene on Ag(100) and explain the anisotropic ordering that is observed experimentally.

Leadership skills help financial managers achieve career success.

PubMed

Kowalski, R B; Campbell, M W

2000-04-01

Financial managers who want to distinguish themselves in their organizations need to demonstrate their leadership ability. Because financial managers sometimes overlook the need for leadership skills, cultivating mentors who can teach them specific leadership skills, such as improved communications and entrepreneurship, may be necessary. Healthcare financial managers can sharpen their leadership skills by distinguishing between leadership and management, adopting a new mentoring model, evaluating the usefulness of new management techniques, understanding the connection between technology and leadership, looking for the solution beyond the problem, and being seen and heard within the organization.

Neural image analysis for estimating aerobic and anaerobic decomposition of organic matter based on the example of straw decomposition

NASA Astrophysics Data System (ADS)

Boniecki, P.; Nowakowski, K.; Slosarz, P.; Dach, J.; Pilarski, K.

2012-04-01

The purpose of the project was to identify the degree of organic matter decomposition by means of a neural model based on graphical information derived from image analysis. Empirical data (photographs of compost content at various stages of maturation) were used to generate an optimal neural classifier (Boniecki et al. 2009, Nowakowski et al. 2009). The best classification properties were found in an RBF (Radial Basis Function) artificial neural network, which demonstrates that the process is non-linear.

[Scientific bases of the organization of psychiatric care: the solution of practical problems in the framework of priority research].

PubMed

Yastrebov, V S; Mitikhin, V G; Solokhina, T A; Mitikhina, I A

ОBJECTIVE: a system analysis and modeling for important areas of research of the organization of psychiatric services in Russia in the study mental health of the population, identification of factors affecting the formation of the contingent of persons with mental disorders, organizational and functional structure of mental health services and mental health care. The authors analyzed scientific publications on the problems of psychiatric care organization as well as the results of own research over the last 25 years using system analysis. The approach that allows a creation of a range of population models to monitor the status of mental health based on medical, demographic and social factors (more than 60 factors) of life was suggested. The basic models and approaches for the evaluation of activity of divisions of mental health services at the macro and micro-social levels, taking into account expert information and individual characteristics of patients and relatives, were demonstrated. To improve treatment quality, the models of identification of the factors, which positively or negatively influenced the commitment to psychopharmacotherapy of patients with schizophrenia and their families, were developed.

Resilience of Cyber Systems with Over- and Underregulation.

PubMed

Gisladottir, Viktoria; Ganin, Alexander A; Keisler, Jeffrey M; Kepner, Jeremy; Linkov, Igor

2017-09-01

Recent cyber attacks provide evidence of increased threats to our critical systems and infrastructure. A common reaction to a new threat is to harden the system by adding new rules and regulations. As federal and state governments request new procedures to follow, each of their organizations implements their own cyber defense strategies. This unintentionally increases time and effort that employees spend on training and policy implementation and decreases the time and latitude to perform critical job functions, thus raising overall levels of stress. People's performance under stress, coupled with an overabundance of information, results in even more vulnerabilities for adversaries to exploit. In this article, we embed a simple regulatory model that accounts for cybersecurity human factors and an organization's regulatory environment in a model of a corporate cyber network under attack. The resulting model demonstrates the effect of under- and overregulation on an organization's resilience with respect to insider threats. Currently, there is a tendency to use ad-hoc approaches to account for human factors rather than to incorporate them into cyber resilience modeling. It is clear that using a systematic approach utilizing behavioral science, which already exists in cyber resilience assessment, would provide a more holistic view for decisionmakers. © 2016 Society for Risk Analysis.

Dose coefficients in pediatric and adult abdominopelvic CT based on 100 patient models.

PubMed

Tian, Xiaoyu; Li, Xiang; Segars, W Paul; Frush, Donald P; Paulson, Erik K; Samei, Ehsan

2013-12-21

Recent studies have shown the feasibility of estimating patient dose from a CT exam using CTDI(vol)-normalized-organ dose (denoted as h), DLP-normalized-effective dose (denoted as k), and DLP-normalized-risk index (denoted as q). However, previous studies were limited to a small number of phantom models. The purpose of this work was to provide dose coefficients (h, k, and q) across a large number of computational models covering a broad range of patient anatomy, age, size percentile, and gender. The study consisted of 100 patient computer models (age range, 0 to 78 y.o.; weight range, 2-180 kg) including 42 pediatric models (age range, 0 to 16 y.o.; weight range, 2-80 kg) and 58 adult models (age range, 18 to 78 y.o.; weight range, 57-180 kg). Multi-detector array CT scanners from two commercial manufacturers (LightSpeed VCT, GE Healthcare; SOMATOM Definition Flash, Siemens Healthcare) were included. A previously-validated Monte Carlo program was used to simulate organ dose for each patient model and each scanner, from which h, k, and q were derived. The relationships between h, k, and q and patient characteristics (size, age, and gender) were ascertained. The differences in conversion coefficients across the scanners were further characterized. CTDI(vol)-normalized-organ dose (h) showed an exponential decrease with increasing patient size. For organs within the image coverage, the average differences of h across scanners were less than 15%. That value increased to 29% for organs on the periphery or outside the image coverage, and to 8% for distributed organs, respectively. The DLP-normalized-effective dose (k) decreased exponentially with increasing patient size. For a given gender, the DLP-normalized-risk index (q) showed an exponential decrease with both increasing patient size and patient age. The average differences in k and q across scanners were 8% and 10%, respectively. This study demonstrated that the knowledge of patient information and CTDIvol/DLP values may be used to estimate organ dose, effective dose, and risk index in abdominopelvic CT based on the coefficients derived from a large population of pediatric and adult patients.

Dose coefficients in pediatric and adult abdominopelvic CT based on 100 patient models

NASA Astrophysics Data System (ADS)

Tian, Xiaoyu; Li, Xiang; Segars, W. Paul; Frush, Donald P.; Paulson, Erik K.; Samei, Ehsan

2013-12-01

Recent studies have shown the feasibility of estimating patient dose from a CT exam using CTDIvol-normalized-organ dose (denoted as h), DLP-normalized-effective dose (denoted as k), and DLP-normalized-risk index (denoted as q). However, previous studies were limited to a small number of phantom models. The purpose of this work was to provide dose coefficients (h, k, and q) across a large number of computational models covering a broad range of patient anatomy, age, size percentile, and gender. The study consisted of 100 patient computer models (age range, 0 to 78 y.o.; weight range, 2-180 kg) including 42 pediatric models (age range, 0 to 16 y.o.; weight range, 2-80 kg) and 58 adult models (age range, 18 to 78 y.o.; weight range, 57-180 kg). Multi-detector array CT scanners from two commercial manufacturers (LightSpeed VCT, GE Healthcare; SOMATOM Definition Flash, Siemens Healthcare) were included. A previously-validated Monte Carlo program was used to simulate organ dose for each patient model and each scanner, from which h, k, and q were derived. The relationships between h, k, and q and patient characteristics (size, age, and gender) were ascertained. The differences in conversion coefficients across the scanners were further characterized. CTDIvol-normalized-organ dose (h) showed an exponential decrease with increasing patient size. For organs within the image coverage, the average differences of h across scanners were less than 15%. That value increased to 29% for organs on the periphery or outside the image coverage, and to 8% for distributed organs, respectively. The DLP-normalized-effective dose (k) decreased exponentially with increasing patient size. For a given gender, the DLP-normalized-risk index (q) showed an exponential decrease with both increasing patient size and patient age. The average differences in k and q across scanners were 8% and 10%, respectively. This study demonstrated that the knowledge of patient information and CTDIvol/DLP values may be used to estimate organ dose, effective dose, and risk index in abdominopelvic CT based on the coefficients derived from a large population of pediatric and adult patients.

Collaborative Research: Polymeric Multiferroics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ren, Shenqiang

2017-04-20

The goal of this project is to investigate room temperature magnetism and magnetoelectric coupling of polymeric multiferroics. A new family of molecular charge-transfer crystals has been emerged as a fascinating opportunity for the development of all-organic electrics and spintronics due to its weak hyperfine interaction and low spin-orbit coupling; nevertheless, direct observations of room temperature magnetic spin ordering have yet to be accomplished in organic charge-transfer solids. Furthermore, room temperature magnetoelectric coupling effect hitherto known multiferroics, is anticipated in organic donor-acceptor complexes because of magnetic field effects on charge-transfer dipoles, yet this is also unexplored. The PI seeks to fundamentalmore » understanding of the control of organic crystals to demonstrate and explore room temperature multiferroicity. The experimental results have been verified through the theoretical modeling.« less

Pattern formation of microtubules and motors: inelastic interaction of polar rods.

PubMed

Aranson, Igor S; Tsimring, Lev S

2005-05-01

We derive a model describing spatiotemporal organization of an array of microtubules interacting via molecular motors. Starting from a stochastic model of inelastic polar rods with a generic anisotropic interaction kernel we obtain a set of equations for the local rods concentration and orientation. At large enough mean density of rods and concentration of motors, the model describes orientational instability. We demonstrate that the orientational instability leads to the formation of vortices and (for large density and/or kernel anisotropy) asters seen in recent experiments.

Neurokernel: An Open Source Platform for Emulating the Fruit Fly Brain

PubMed Central

2016-01-01

We have developed an open software platform called Neurokernel for collaborative development of comprehensive models of the brain of the fruit fly Drosophila melanogaster and their execution and testing on multiple Graphics Processing Units (GPUs). Neurokernel provides a programming model that capitalizes upon the structural organization of the fly brain into a fixed number of functional modules to distinguish between these modules’ local information processing capabilities and the connectivity patterns that link them. By defining mandatory communication interfaces that specify how data is transmitted between models of each of these modules regardless of their internal design, Neurokernel explicitly enables multiple researchers to collaboratively model the fruit fly’s entire brain by integration of their independently developed models of its constituent processing units. We demonstrate the power of Neurokernel’s model integration by combining independently developed models of the retina and lamina neuropils in the fly’s visual system and by demonstrating their neuroinformation processing capability. We also illustrate Neurokernel’s ability to take advantage of direct GPU-to-GPU data transfers with benchmarks that demonstrate scaling of Neurokernel’s communication performance both over the number of interface ports exposed by an emulation’s constituent modules and the total number of modules comprised by an emulation. PMID:26751378

Refractory Access Disorders and the Organization of Concrete and Abstract Semantics: Do they Differ?

PubMed Central

Hamilton, A. Cris; Coslett, H. Branch

2010-01-01

Patients with “refractory semantic access deficits” demonstrate several unique features that make them important sources of insight into the organization of semantic representations. Here we attempt to replicate several novel findings from single-case studies reported in the literature. Patient UM– 103 displays the cardinal features of a “refractory semantic access deficit” and showed many of the same effects of semantic relatedness reported in the literature. However, when probing concrete and abstract words, this patient revealed very different patterns of performance compared to two previously reported patients. We discuss the implications of our data for models of semantic organization of abstract and concrete words. PMID:18569737

Exciton delocalization incorporated drift-diffusion model for bulk-heterojunction organic solar cells

NASA Astrophysics Data System (ADS)

Wang, Zi Shuai; Sha, Wei E. I.; Choy, Wallace C. H.

2016-12-01

Modeling the charge-generation process is highly important to understand device physics and optimize power conversion efficiency of bulk-heterojunction organic solar cells (OSCs). Free carriers are generated by both ultrafast exciton delocalization and slow exciton diffusion and dissociation at the heterojunction interface. In this work, we developed a systematic numerical simulation to describe the charge-generation process by a modified drift-diffusion model. The transport, recombination, and collection of free carriers are incorporated to fully capture the device response. The theoretical results match well with the state-of-the-art high-performance organic solar cells. It is demonstrated that the increase of exciton delocalization ratio reduces the energy loss in the exciton diffusion-dissociation process, and thus, significantly improves the device efficiency, especially for the short-circuit current. By changing the exciton delocalization ratio, OSC performances are comprehensively investigated under the conditions of short-circuit and open-circuit. Particularly, bulk recombination dependent fill factor saturation is unveiled and understood. As a fundamental electrical analysis of the delocalization mechanism, our work is important to understand and optimize the high-performance OSCs.

Models of plasma membrane organization can be applied to mitochondrial membranes to target human health and disease with polyunsaturated fatty acids.

PubMed

Raza Shaikh, Saame; Brown, David A

2013-01-01

Bioactive n-3 polyunsaturated fatty acids (PUFA), abundant in fish oil, have potential for treating symptoms associated with inflammatory and metabolic disorders; therefore, it is essential to determine their fundamental molecular mechanisms. Recently, several labs have demonstrated the n-3 PUFA docosahexaenoic acid (DHA) exerts anti-inflammatory effects by targeting the molecular organization of plasma membrane microdomains. Here we briefly review the evidence that DHA reorganizes the spatial distribution of microdomains in several model systems. We then emphasize how models on DHA and plasma membrane microdomains can be applied to mitochondrial membranes. We discuss the role of DHA acyl chains in regulating mitochondrial lipid-protein clustering, and how these changes alter several aspects of mitochondrial function. In particular, we summarize effects of DHA on mitochondrial respiration, electron leak, permeability transition, and mitochondrial calcium handling. Finally, we conclude by postulating future experiments that will augment our understanding of DHA-dependent membrane organization in health and disease. Copyright © 2012 Elsevier Ltd. All rights reserved.

The epicurean fly: using Drosophila melanogaster to study metabolism.

PubMed

Bharucha, Kamal N

2009-02-01

In this review, the utility of Drosophila melanogaster as a model organism for research in metabolism will be demonstrated. Importantly, many metabolic pathways are conserved in both man and the fly. Recent work has highlighted that these conserved molecular pathways have the potential to give rise to similar phenotypes. For example, it has proven possible to generate obese and diabetic Drosophila; conversely, genetic manipulation can also generate lean and hypoglycemic phenotypes. From conserved circulating hormones to key enzymes, the fly is host to a variety of homologous, metabolically active signaling mechanisms. The world of Drosophila research has not only a rich history of developing techniques for exquisite genetic manipulation, but also continues to develop genetic methodologies at an exciting rate. Many of these techniques add to the cadre of experimental tools available for the use of the fly as a model organism for studying carbohydrate and lipid homeostasis. This review is written for the pediatric-scientist with little background in Drosophila, with the goal of relaying the potential of this model organism for contributing to a better understanding of diseases affecting today's children.

A Genome-Wide Association Study Identifies Genomic Regions for Virulence in the Non-Model Organism Heterobasidion annosum s.s

PubMed Central

Dalman, Kerstin; Himmelstrand, Kajsa; Olson, Åke; Lind, Mårten; Brandström-Durling, Mikael; Stenlid, Jan

2013-01-01

The dense single nucleotide polymorphisms (SNP) panels needed for genome wide association (GWA) studies have hitherto been expensive to establish and use on non-model organisms. To overcome this, we used a next generation sequencing approach to both establish SNPs and to determine genotypes. We conducted a GWA study on a fungal species, analysing the virulence of Heterobasidion annosum s.s., a necrotrophic pathogen, on its hosts Picea abies and Pinus sylvestris. From a set of 33,018 single nucleotide polymorphisms (SNP) in 23 haploid isolates, twelve SNP markers distributed on seven contigs were associated with virulence (P<0.0001). Four of the contigs harbour known virulence genes from other fungal pathogens and the remaining three harbour novel candidate genes. Two contigs link closely to virulence regions recognized previously by QTL mapping in the congeneric hybrid H. irregulare × H. occidentale. Our study demonstrates the efficiency of GWA studies for dissecting important complex traits of small populations of non-model haploid organisms with small genomes. PMID:23341945

Accelerated Discovery of High-Refractive-Index Polymers Using First-Principles Modeling, Virtual High-Throughput Screening, and Data Mining

NASA Astrophysics Data System (ADS)

Afzal, Mohammad Atif Faiz; Cheng, Chong; Hachmann, Johannes

Organic materials with refractive index (RI) values higher than 1.7 have attracted considerable interest in recent years due to the tremendous potential for their application in optical, optometric, and optoelectronic devices, and thus for shaping technological innovation in numerous related areas. Our work is concerned with creating predictive models for the optical properties of organic polymers, which will guide our experimentalist partners and allow them to target the most promising candidates. The RI model is developed based on a synergistic combination of first-principles electronic structure theory and machine learning techniques. The RI values predicted for common polymers using this model are in very good agreement with the experimental values. We also benchmark different DFT approximations along with various basis sets for their predictive performance in this model. We demonstrate that this combination of first-principles and data modeling is both successful and highly economical in determining the RI values of a wide range of organic polymers. To accelerate the development process, we cast this modeling approach into the high-throughput screening, materials informatics, and rational design framework that is developed in the group. This framework is a powerful tool and has shown to be highly promising for rapidly identifying polymer candidates with exceptional RI values as well as discovering design rules for advanced materials.

β-Glucans Are Masked but Contribute to Pulmonary Inflammation During Pneumocystis Pneumonia

PubMed Central

Kutty, Geetha; Davis, A. Sally; Ferreyra, Gabriela A.; Qiu, Ju; Huang, Da Wei; Sassi, Monica; Bishop, Lisa; Handley, Grace; Sherman, Brad; Lempicki, Richard; Kovacs, Joseph A.

2016-01-01

β-glucans, which can activate innate immune responses, are a major component in the cell wall of the cyst form of Pneumocystis. In the current study, we examined whether β-1,3-glucans are masked by surface proteins in Pneumocystis and what role β-glucans play in Pneumocystis-associated inflammation. For 3 species, including Pneumocystis jirovecii, which causes Pneumocystis pneumonia in humans, Pneumocystis carinii, and Pneumocystis murina, β-1,3-glucans were masked in most organisms, as demonstrated by increased exposure following trypsin treatment. Using quantitative polymerase chain reaction and microarray techniques, we demonstrated in a mouse model of Pneumocystis pneumonia that treatment with caspofungin, an inhibitor of β-1,3-glucan synthesis, for 21 days decreased expression of a broad panel of inflammatory markers, including interferon γ, tumor necrosis factor α, interleukin 1β, interleukin 6, and multiple chemokines/chemokine ligands. Thus, β-glucans in Pneumocystis cysts are largely masked, which likely decreases innate immune activation; this mechanism presumably was developed for interactions with immunocompetent hosts, in whom organism loads are substantially lower. In immunosuppressed hosts with a high organism burden, organism death and release of glucans appears to be an important contributor to deleterious host inflammatory responses. PMID:27324243

Empowerment Praxis: Community Organizing to Redress Systemic Health Disparities.

PubMed

Douglas, Jason A; Grills, Cheryl T; Villanueva, Sandra; Subica, Andrew M

2016-12-01

Social and environmental determinants of childhood obesity present a public health dilemma, particularly in low-income communities of color. Case studies of two community-based organizations participating in the Robert Wood Johnson Foundation's Communities Creating Healthy Environments (CCHE) childhood obesity initiative demonstrate multilevel, culturally situated community organizing strategies to address the root causes of this public health disparity. Informed by a 3-lens prescription-Social Justice, Culture-Place, and Organizational Capacity-contained in the CCHE Change Model and Evaluation Frame, we present examples of individual, organizational, and community empowerment to redress systemic inequities that manifest in poor health outcomes for people of color. These case studies offer compelling evidence that public health disparities in these communities may effectively be abated through strategies that employ bottom-up, community-level approaches for (a) identifying proximal and distal determinants of public health disparities, and (b) empowering communities to directly redress these inequities. Guided by this ecological framework, application of the CCHE evaluation approach demonstrated the necessity to document the granularity of community organizing for community health, adding to the community psychology literature on empowering processes and outcomes. © Society for Community Research and Action 2016.

Alteration of rocks by endolithic organisms is one of the pathways for the beginning of soils on Earth.

PubMed

Mergelov, Nikita; Mueller, Carsten W; Prater, Isabel; Shorkunov, Ilya; Dolgikh, Andrey; Zazovskaya, Elya; Shishkov, Vasily; Krupskaya, Victoria; Abrosimov, Konstantin; Cherkinsky, Alexander; Goryachkin, Sergey

2018-02-20

Subaerial endolithic systems of the current extreme environments on Earth provide exclusive insight into emergence and development of soils in the Precambrian when due to various stresses on the surfaces of hard rocks the cryptic niches inside them were much more plausible habitats for organisms than epilithic ones. Using an actualistic approach we demonstrate that transformation of silicate rocks by endolithic organisms is one of the possible pathways for the beginning of soils on Earth. This process led to the formation of soil-like bodies on rocks in situ and contributed to the raise of complexity in subaerial geosystems. Endolithic systems of East Antarctica lack the noise from vascular plants and are among the best available natural models to explore organo-mineral interactions of a very old "phylogenetic age" (cyanobacteria-to-mineral, fungi-to-mineral, lichen-to-mineral). On the basis of our case study from East Antarctica we demonstrate that relatively simple endolithic systems of microbial and/or cryptogamic origin that exist and replicate on Earth over geological time scales employ the principles of organic matter stabilization strikingly similar to those known for modern full-scale soils of various climates.

Virulence of Curvularia in a murine model.

PubMed

Paredes, Katihuska; Capilla, Javier; Sutton, Deanna A; Mayayo, Emilio; Fothergill, Annette W; Guarro, Josep

2013-09-01

We have evaluated the virulence of two clinically relevant species of Curvularia; Curvularia spicifera and C. hawaiiensis, using an experimental model of disseminated infection in immunocompromised mice. Several inocula were tested over a range 1 × 10(3) -1 × 10(6) colony-forming units/animal. Both species had a similar behaviour, producing a high mortality. Tissue burden and histopathology studies demonstrated that lung was the organ most affected. © 2013 Blackwell Verlag GmbH.

Multispectral imaging of organ viability during uterine transplantation surgery in rabbits and sheep

NASA Astrophysics Data System (ADS)

Clancy, Neil T.; Saso, Srdjan; Stoyanov, Danail; Sauvage, Vincent; Corless, David J.; Boyd, Michael; Noakes, David E.; Thum, Meen-Yau; Ghaem-Maghami, Sadaf; Smith, James Richard; Elson, Daniel S.

2016-10-01

Uterine transplantation surgery (UTx) has been proposed as a treatment for permanent absolute uterine factor infertility (AUFI) in the case of the congenital absence or surgical removal of the uterus. Successful surgical attachment of the organ and its associated vasculature is essential for the organ's reperfusion and long-term viability. Spectral imaging techniques have demonstrated the potential for the measurement of hemodynamics in medical applications. These involve the measurement of reflectance spectra by acquiring images of the tissue in different wavebands. Measures of tissue constituents at each pixel can then be extracted from these spectra through modeling of the light-tissue interaction. A multispectral imaging (MSI) laparoscope was used in sheep and rabbit UTx models to study short- and long-term changes in oxygen saturation following surgery. The whole organ was imaged in the donor and recipient animals in parallel with point measurements from a pulse oximeter. Imaging results confirmed the re-establishment of adequate perfusion in the transplanted organ after surgery. Cornual oxygenation trends measured with MSI are consistent with pulse oximeter readings, showing decreased StO2 immediately after anastomosis of the blood vessels. Long-term results show recovery of StO2 to preoperative levels.

Dynamic updating of hippocampal object representations reflects new conceptual knowledge

PubMed Central

Mack, Michael L.; Love, Bradley C.; Preston, Alison R.

2016-01-01

Concepts organize the relationship among individual stimuli or events by highlighting shared features. Often, new goals require updating conceptual knowledge to reflect relationships based on different goal-relevant features. Here, our aim is to determine how hippocampal (HPC) object representations are organized and updated to reflect changing conceptual knowledge. Participants learned two classification tasks in which successful learning required attention to different stimulus features, thus providing a means to index how representations of individual stimuli are reorganized according to changing task goals. We used a computational learning model to capture how people attended to goal-relevant features and organized object representations based on those features during learning. Using representational similarity analyses of functional magnetic resonance imaging data, we demonstrate that neural representations in left anterior HPC correspond with model predictions of concept organization. Moreover, we show that during early learning, when concept updating is most consequential, HPC is functionally coupled with prefrontal regions. Based on these findings, we propose that when task goals change, object representations in HPC can be organized in new ways, resulting in updated concepts that highlight the features most critical to the new goal. PMID:27803320

Authentication of Organically and Conventionally Grown Basils by Gas Chromatography/Mass Spectrometry Chemical Profiles

PubMed Central

Wang, Zhengfang; Chen, Pei; Yu, Liangli; Harrington, Peter de B.

2013-01-01

Basil plants cultivated by organic and conventional farming practices were accurately classified by pattern recognition of gas chromatography/mass spectrometry (GC/MS) data. A novel extraction procedure was devised to extract characteristic compounds from ground basil powders. Two in-house fuzzy classifiers, i.e., the fuzzy rule-building expert system (FuRES) and the fuzzy optimal associative memory (FOAM) for the first time, were used to build classification models. Two crisp classifiers, i.e., soft independent modeling by class analogy (SIMCA) and the partial least-squares discriminant analysis (PLS-DA), were used as control methods. Prior to data processing, baseline correction and retention time alignment were performed. Classifiers were built with the two-way data sets, the total ion chromatogram representation of data sets, and the total mass spectrum representation of data sets, separately. Bootstrapped Latin partition (BLP) was used as an unbiased evaluation of the classifiers. By using two-way data sets, average classification rates with FuRES, FOAM, SIMCA, and PLS-DA were 100 ± 0%, 94.4 ± 0.4%, 93.3 ± 0.4%, and 100 ± 0%, respectively, for 100 independent evaluations. The established classifiers were used to classify a new validation set collected 2.5 months later with no parametric changes except that the training set and validation set were individually mean-centered. For the new two-way validation set, classification rates with FuRES, FOAM, SIMCA, and PLS-DA were 100%, 83%, 97%, and 100%, respectively. Thereby, the GC/MS analysis was demonstrated as a viable approach for organic basil authentication. It is the first time that a FOAM has been applied to classification. A novel baseline correction method was used also for the first time. The FuRES and the FOAM are demonstrated as powerful tools for modeling and classifying GC/MS data of complex samples and the data pretreatments are demonstrated to be useful to improve the performance of classifiers. PMID:23398171

Daemen Alternative Energy/Geothermal Technologies Demonstration Program Erie County

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beiswanger, Jr, Robert C

2010-05-20

The purpose of the Daemen Alternative Energy/Geothermal Technologies Demonstration Project is to demonstrate the use of geothermal technology as model for energy and environmental efficiency in heating and cooling older, highly inefficient buildings. The former Marian Library building at Daemen College is a 19,000 square foot building located in the center of campus. Through this project, the building was equipped with geothermal technology and results were disseminated. Gold LEED certification for the building was awarded. 1) How the research adds to the understanding of the area investigated. This project is primarily a demonstration project. Information about the installation is availablemore » to other companies, organizations, and higher education institutions that may be interested in using geothermal energy for heating and cooling older buildings. 2) The technical effectiveness and economic feasibility of the methods or techniques investigated or demonstrated. According to the modeling and estimates through Stantec, the energy-efficiency cost savings is estimated at 20%, or $24,000 per year. Over 20 years this represents $480,000 in unrestricted revenue available for College operations. See attached technical assistance report. 3) How the project is otherwise of benefit to the public. The Daemen College Geothermal Technologies Ground Source Heat Pumps project sets a standard for retrofitting older, highly inefficient, energy wasting and environmentally irresponsible buildings quite typical of many of the buildings on the campuses of regional colleges and universities. As a model, the project serves as an energy-efficient system with significant environmental advantages. Information about the energy-efficiency measures is available to other colleges and universities, organizations and companies, students, and other interested parties. The installation and renovation provided employment for 120 individuals during the award period. Through the new Center, Daemen will continue to host a range of events on campus for the general public. The College does not charge fees for speakers or most other events. This has been a long-standing tradition of the College.« less

Daemen Alternative Energy/Geothermal Technologies Demonstration Program, Erie County

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beiswanger, Robert C.

The purpose of the Daemen Alternative Energy/Geothermal Technologies Demonstration Project is to demonstrate the use of geothermal technology as model for energy and environmental efficiency in heating and cooling older, highly inefficient buildings. The former Marian Library building at Daemen College is a 19,000 square foot building located in the center of campus. Through this project, the building was equipped with geothermal technology and results were disseminated. Gold LEED certification for the building was awarded. 1) How the research adds to the understanding of the area investigated. This project is primarily a demonstration project. Information about the installation is availablemore » to other companies, organizations, and higher education institutions that may be interested in using geothermal energy for heating and cooling older buildings. 2) The technical effectiveness and economic feasibility of the methods or techniques investigated or demonstrated. According to the modeling and estimates through Stantec, the energy-efficiency cost savings is estimated at 20%, or $24,000 per year. Over 20 years this represents $480,000 in unrestricted revenue available for College operations. See attached technical assistance report. 3) How the project is otherwise of benefit to the public. The Daemen College Geothermal Technologies Ground Source Heat Pumps project sets a standard for retrofitting older, highly inefficient, energy wasting and environmentally irresponsible buildings that are quite typical of many of the buildings on the campuses of regional colleges and universities. As a model, the project serves as an energy-efficient system with significant environmental advantages. Information about the energy-efficiency measures is available to other colleges and universities, organizations and companies, students, and other interested parties. The installation and renovation provided employment for 120 individuals during the award period. Through the new Center, Daemen will continue to host a range of events on campus for the general public. The College does not charge fees for speakers or most other events. This has been a long-standing tradition of the College.« less

Modeling Multi-Agent Self-Organization through the Lens of Higher Order Attractor Dynamics.

PubMed

Butner, Jonathan E; Wiltshire, Travis J; Munion, A K

2017-01-01

Social interaction occurs across many time scales and varying numbers of agents; from one-on-one to large-scale coordination in organizations, crowds, cities, and colonies. These contexts, are characterized by emergent self-organization that implies higher order coordinated patterns occurring over time that are not due to the actions of any particular agents, but rather due to the collective ordering that occurs from the interactions of the agents. Extant research to understand these social coordination dynamics (SCD) has primarily examined dyadic contexts performing rhythmic tasks. To advance this area of study, we elaborate on attractor dynamics, our ability to depict them visually, and quantitatively model them. Primarily, we combine difference/differential equation modeling with mixture modeling as a way to infer the underlying topological features of the data, which can be described in terms of attractor dynamic patterns. The advantage of this approach is that we are able to quantify the self-organized dynamics that agents exhibit, link these dynamics back to activity from individual agents, and relate it to other variables central to understanding the coordinative functionality of a system's behavior. We present four examples that differ in the number of variables used to depict the attractor dynamics (1, 2, and 6) and range from simulated to non-simulated data sources. We demonstrate that this is a flexible method that advances scientific study of SCD in a variety of multi-agent systems.

Visualization of risk of radiogenic second cancer in the organs and tissues of the human body.

PubMed

Zhang, Rui; Mirkovic, Dragan; Newhauser, Wayne D

2015-04-28

Radiogenic second cancer is a common late effect in long term cancer survivors. Currently there are few methods or tools available to visually evaluate the spatial distribution of risks of radiogenic late effects in the human body. We developed a risk visualization method and demonstrated it for radiogenic second cancers in tissues and organs of one patient treated with photon volumetric modulated arc therapy and one patient treated with proton craniospinal irradiation. Treatment plans were generated using radiotherapy treatment planning systems (TPS) and dose information was obtained from TPS. Linear non-threshold risk coefficients for organs at risk of second cancer incidence were taken from the Biological Effects of Ionization Radiation VII report. Alternative risk models including linear exponential model and linear plateau model were also examined. The predicted absolute lifetime risk distributions were visualized together with images of the patient anatomy. The risk distributions of second cancer for the two patients were visually presented. The risk distributions varied with tissue, dose, dose-risk model used, and the risk distribution could be similar to or very different from the dose distribution. Our method provides a convenient way to directly visualize and evaluate the risks of radiogenic second cancer in organs and tissues of the human body. In the future, visual assessment of risk distribution could be an influential determinant for treatment plan scoring.

The Evolving MCART Multimodal Imaging Core: Establishing a protocol for Computed Tomography and Echocardiography in the Rhesus macaque to perform longitudinal analysis of radiation-induced organ injury

PubMed Central

de Faria, Eduardo B.; Barrow, Kory R.; Ruehle, Bradley T.; Parker, Jordan T.; Swartz, Elisa; Taylor-Howell, Cheryl; Kieta, Kaitlyn M.; Lees, Cynthia J.; Sleeper, Meg M.; Dobbin, Travis; Baron, Adam D.; Mohindra, Pranshu; MacVittie, Thomas J.

2015-01-01

Computed Tomography (CT) and Echocardiography (EC) are two imaging modalities that produce critical longitudinal data that can be analyzed for radiation-induced organ-specific injury to the lung and heart. The Medical Countermeasures Against Radiological Threats (MCART) consortium has a well-established animal model research platform that includes nonhuman primate (NHP) models of the acute radiation syndrome and the delayed effects of acute radiation exposure. These models call for a definition of the latency, incidence, severity, duration, and resolution of different organ-specific radiation-induced subsyndromes. The pulmonary subsyndromes and cardiac effects are a pair of inter-dependent syndromes impacted by exposure to potentially lethal doses of radiation. Establishing a connection between these will reveal important information about their interaction and progression of injury and recovery. Herein, we demonstrate the use of CT and EC data in the rhesus macaque models to define delayed organ injury thereby establishing: a) consistent and reliable methodology to assess radiation-induced damage to the lung and heart, b) an extensive database in normal age-matched NHP for key primary and secondary endpoints, c) identified problematic variables in imaging techniques and proposed solutions to maintain data integrity and d) initiated longitudinal analysis of potentially lethal radiation-induced damage to the lung and heart. PMID:26425907

A simple approach to estimate daily loads of total, refractory, and labile organic carbon from their seasonal loads in a watershed.

PubMed

Ouyang, Ying; Grace, Johnny M; Zipperer, Wayne C; Hatten, Jeff; Dewey, Janet

2018-05-22

Loads of naturally occurring total organic carbons (TOC), refractory organic carbon (ROC), and labile organic carbon (LOC) in streams control the availability of nutrients and the solubility and toxicity of contaminants and affect biological activities through absorption of light and complex metals with production of carcinogenic compounds. Although computer models have become increasingly popular in understanding and management of TOC, ROC, and LOC loads in streams, the usefulness of these models hinges on the availability of daily data for model calibration and validation. Unfortunately, these daily data are usually insufficient and/or unavailable for most watersheds due to a variety of reasons, such as budget and time constraints. A simple approach was developed here to calculate daily loads of TOC, ROC, and LOC in streams based on their seasonal loads. We concluded that the predictions from our approach adequately match field measurements based on statistical comparisons between model calculations and field measurements. Our approach demonstrates that an increase in stream discharge results in increased stream TOC, ROC, and LOC concentrations and loads, although high peak discharge did not necessarily result in high peaks of TOC, ROC, and LOC concentrations and loads. The approach developed herein is a useful tool to convert seasonal loads of TOC, ROC, and LOC into daily loads in the absence of measured daily load data.

Compact Two-step Laser Time-of-Flight Mass Spectrometer for in Situ Analyses of Aromatic Organics on Planetary Missions

NASA Technical Reports Server (NTRS)

Getty, Stephanie; Brickerhoff, William; Cornish, Timothy; Ecelberger, Scott; Floyd, Melissa

2012-01-01

RATIONALE A miniature time-of-flight mass spectrometer has been adapted to demonstrate two-step laser desorption-ionization (LOI) in a compact instrument package for enhanced organics detection. Two-step LDI decouples the desorption and ionization processes, relative to traditional laser ionization-desorption, in order to produce low-fragmentation conditions for complex organic analytes. Tuning UV ionization laser energy allowed control ofthe degree of fragmentation, which may enable better identification of constituent species. METHODS A reflectron time-of-flight mass spectrometer prototype measuring 20 cm in length was adapted to a two-laser configuration, with IR (1064 nm) desorption followed by UV (266 nm) postionization. A relatively low ion extraction voltage of 5 kV was applied at the sample inlet. Instrument capabilities and performance were demonstrated with analysis of a model polycyclic aromatic hydrocarbon, representing a class of compounds important to the fields of Earth and planetary science. RESULTS L2MS analysis of a model PAH standard, pyrene, has been demonstrated, including parent mass identification and the onset o(tunable fragmentation as a function of ionizing laser energy. Mass resolution m/llm = 380 at full width at half-maximum was achieved which is notable for gas-phase ionization of desorbed neutrals in a highly-compact mass analyzer. CONCLUSIONS Achieving two-step laser mass spectrometry (L2MS) in a highly-miniature instrument enables a powerful approach to the detection and characterization of aromatic organics in remote terrestrial and planetary applications. Tunable detection of parent and fragment ions with high mass resolution, diagnostic of molecular structure, is possible on such a compact L2MS instrument. Selectivity of L2MS against low-mass inorganic salt interferences is a key advantage when working with unprocessed, natural samples, and a mechanism for the observed selectivity is presented.

Functional lacrimal gland regeneration by transplantation of a bioengineered organ germ

PubMed Central

Hirayama, Masatoshi; Ogawa, Miho; Oshima, Masamitsu; Sekine, Yurie; Ishida, Kentaro; Yamashita, Kentaro; Ikeda, Kazutaka; Shimmura, Shigeto; Kawakita, Tetsuya; Tsubota, Kazuo; Tsuji, Takashi

2013-01-01

The lacrimal gland has a multifaceted role in maintaining a homeostatic microenvironment for a healthy ocular surface via tear secretion. Dry-eye disease, which is caused by lacrimal gland dysfunction, is one of the most prevalent eye diseases that cause corneal epithelial damage and results in significant loss of vision and a reduction in the quality of life. Here we demonstrate orthotopic transplantation of bioengineered lacrimal gland germs into adult mice with an extra-orbital lacrimal gland defect, a mouse model that mimics the corneal epithelial damage caused by lacrimal gland dysfunction. The bioengineered lacrimal gland germs and harderian gland germs both develop in vivo and achieve sufficient physiological functionality, including tear production in response to nervous stimulation and ocular surface protection. This study demonstrates the potential for bioengineered organ replacement to functionally restore the lacrimal gland. PMID:24084941

Approach to high quality GaN lateral nanowires and planar cavities fabricated by focused ion beam and metal-organic vapor phase epitaxy.

PubMed

Pozina, Galia; Gubaydullin, Azat R; Mitrofanov, Maxim I; Kaliteevski, Mikhail A; Levitskii, Iaroslav V; Voznyuk, Gleb V; Tatarinov, Evgeniy E; Evtikhiev, Vadim P; Rodin, Sergey N; Kaliteevskiy, Vasily N; Chechurin, Leonid S

2018-05-08

We have developed a method to fabricate GaN planar nanowires and cavities by combination of Focused Ion Beam (FIB) patterning of the substrate followed by Metal Organic Vapor Phase Epitaxy (MOVPE). The method includes depositing a silicon nitride mask on a sapphire substrate, etching of the trenches in the mask by FIB with a diameter of 40 nm with subsequent MOVPE growth of GaN within trenches. It was observed that the growth rate of GaN is substantially increased due to enhanced bulk diffusion of the growth precursor therefore the model for analysis of the growth rate was developed. The GaN strips fabricated by this method demonstrate effective luminescence properties. The structures demonstrate enhancement of spontaneous emission via formation of Fabry-Perot modes.

A phase field approach for multicellular aggregate fusion in biofabrication.

PubMed

Yang, Xiaofeng; Sun, Yi; Wang, Qi

2013-07-01

We present a modeling and computational approach to study fusion of multicellular aggregates during tissue and organ fabrication, which forms the foundation for the scaffold-less biofabrication of tissues and organs known as bioprinting. It is known as the phase field method, where multicellular aggregates are modeled as mixtures of multiphase complex fluids whose phase mixing or separation is governed by interphase force interactions, mimicking the cell-cell interaction in the multicellular aggregates, and intermediate range interaction mediated by the surrounding hydrogel. The material transport in the mixture is dictated by hydrodynamics as well as forces due to the interphase interactions. In a multicellular aggregate system with fixed number of cells and fixed amount of the hydrogel medium, the effect of cell differentiation, proliferation, and death are neglected in the current model, which can be readily included in the model, and the interaction between different components is dictated by the interaction energy between cell and cell as well as between cell and medium particles, respectively. The modeling approach is applicable to transient simulations of fusion of cellular aggregate systems at the time and length scale appropriate to biofabrication. Numerical experiments are presented to demonstrate fusion and cell sorting during tissue and organ maturation processes in biofabrication.

Modulation of fibronectin-mediated Bacillus Calmette-Guérin attachment to murine bladder mucosa by drugs influencing the coagulation pathways.

PubMed

Hudson, M A; Brown, E J; Ritchey, J K; Ratliff, T L

1991-07-15

Adjuvant intravesical Bacillus Calmette-Guérin (BCG) has proved to be an effective treatment for superficial bladder cancer. Intraluminal attachment of BCG organisms via binding to the extracellular matrix protein, fibronectin (FN), appears to be required for expression of the antitumor efficacy of BCG against a murine bladder tumor. Initial studies demonstrated that radiolabeled FN localized to the acutely injured urothelium but not to intact urothelium. These studies also demonstrated that exogenous administration of FN enhanced BCG attachment to the injured but not to the intact urothelium. Because FN has been shown to be an integral part of clot formation at sites of urothelial injury, drugs known to affect fibrin clot formation were tested for their effects on BCG attachment and antitumor efficacy in a murine bladder tumor model. A stabilizer of fibrin clot formation was shown to enhance both BCG attachment and antitumor efficacy in the same model. An increased number of BCG organisms were also retained in the lymph nodes and spleens of mice receiving fibrin clot stabilizers, suggesting indirectly that immunological mechanisms are involved in the antitumor efficacy of BCG. The data presented herein provide further support for the hypothesis that BCG attachment to the injured bladder is mediated by FN. Furthermore, modulation of BCG-FN attachment is demonstrated to be possible with drugs influencing the coagulation pathway. This attachment is shown to be required for the antitumor efficacy in a murine bladder tumor model, and thus modulation of BCG-FN attachment appears to have significant influence on the antitumor efficacy of BCG in the murine bladder tumor model.

The sorption kinetics and isotherms of sulfamethoxazole with polyethylene microplastics.

PubMed

Xu, Baile; Liu, Fei; Brookes, Philip C; Xu, Jianming

2018-06-01

Microplastics and sulfamethoxazole coexist ubiquitously in the marine environment, and microplastics tend to sorb organic pollutants from the surrounding environment. Here, the sorption kinetics and isotherms of sulfamethoxazole on polyethylene (PE) microplastics closely fitted a pseudo-second-order model (R 2  = 0.98) and linear model (R 2  = 0.99), respectively, indicating that the sorption process was partition-dominant interaction. The main binding mechanism was possibly the van der Waals interaction for hydrophilic sulfamethoxazole onto hydrophobic PE microplastics. The effects of pH, dissolved organic matter and salinity on sorption behavior were also studied. The sorption behavior of sulfamethoxazole on PE microplastics was not significantly influenced by pH and salinity, probably because the electrostatic repulsion played a minor role. In addition, the negligible effect of dissolved organic matter was attributed to the greater affinity of sulfamethoxazole to PE microplastics than to dissolved organic matter. Our results demonstrated that PE microplastics may serve as a carrier for sulfamethoxazole in the aquatic environment. Copyright © 2018 Elsevier Ltd. All rights reserved.

Biocuration at the Saccharomyces genome database.

PubMed

Skrzypek, Marek S; Nash, Robert S

2015-08-01

Saccharomyces Genome Database is an online resource dedicated to managing information about the biology and genetics of the model organism, yeast (Saccharomyces cerevisiae). This information is derived primarily from scientific publications through a process of human curation that involves manual extraction of data and their organization into a comprehensive system of knowledge. This system provides a foundation for further analysis of experimental data coming from research on yeast as well as other organisms. In this review we will demonstrate how biocuration and biocurators add a key component, the biological context, to our understanding of how genes, proteins, genomes and cells function and interact. We will explain the role biocurators play in sifting through the wealth of biological data to incorporate and connect key information. We will also discuss the many ways we assist researchers with their various research needs. We hope to convince the reader that manual curation is vital in converting the flood of data into organized and interconnected knowledge, and that biocurators play an essential role in the integration of scientific information into a coherent model of the cell. © 2015 Wiley Periodicals, Inc.

Biocuration at the Saccharomyces Genome Database

PubMed Central

Skrzypek, Marek S.; Nash, Robert S.

2015-01-01

Saccharomyces Genome Database is an online resource dedicated to managing information about the biology and genetics of the model organism, yeast (Saccharomyces cerevisiae). This information is derived primarily from scientific publications through a process of human curation that involves manual extraction of data and their organization into a comprehensive system of knowledge. This system provides a foundation for further analysis of experimental data coming from research on yeast as well as other organisms. In this review we will demonstrate how biocuration and biocurators add a key component, the biological context, to our understanding of how genes, proteins, genomes and cells function and interact. We will explain the role biocurators play in sifting through the wealth of biological data to incorporate and connect key information. We will also discuss the many ways we assist researchers with their various research needs. We hope to convince the reader that manual curation is vital in converting the flood of data into organized and interconnected knowledge, and that biocurators play an essential role in the integration of scientific information into a coherent model of the cell. PMID:25997651

The impact of the Fermi-Dirac distribution on charge injection at metal/organic interfaces.

PubMed

Wang, Z B; Helander, M G; Greiner, M T; Lu, Z H

2010-05-07

The Fermi level has historically been assumed to be the only energy-level from which carriers are injected at metal/semiconductor interfaces. In traditional semiconductor device physics, this approximation is reasonable as the thermal distribution of delocalized states in the semiconductor tends to dominate device characteristics. However, in the case of organic semiconductors the weak intermolecular interactions results in highly localized electronic states, such that the thermal distribution of carriers in the metal may also influence device characteristics. In this work we demonstrate that the Fermi-Dirac distribution of carriers in the metal has a much more significant impact on charge injection at metal/organic interfaces than has previously been assumed. An injection model which includes the effect of the Fermi-Dirac electron distribution was proposed. This model has been tested against experimental data and was found to provide a better physical description of charge injection. This finding indicates that the thermal distribution of electronic states in the metal should, in general, be considered in the study of metal/organic interfaces.

The Impact of Deviation from Michaelis-Menten Saturation on Mathematical Model Stability Properties

NASA Technical Reports Server (NTRS)

Blackwell, Charles; Kliss, Mark (Technical Monitor)

1998-01-01

Based on purely abstract ecological theory, it has been argued that a system composed of two or more consumers competing for the same resource cannot persist. By analysis on a Monod format mathematical model, Hubble and others demonstrated that this assertion is true for all but very special cases of such competing organisms which are determined by an index formed by a grouping of. the parameters which characterize the biological processes of the competing organisms. In the laboratory, using a bioreactor, Hansen and Hubble obtained confirmatory results for several cases of two competing species, and they characterized it as "qualitative confirmation" of the assertion. This result is amazing, since the analysis required the exact equality of the hey index, and it seems certain that no pair of organism species could have exactly equal values. It is quite plausible, however, that pairs of organism species could have approximately equal indices, and the question of how different they could be and still have coexistence of the two (or more) presents itself. In this paper, the pursuit of this question and a compatible resolution is presented.

Application of Bayesian inference to the study of hierarchical organization in self-organized complex adaptive systems

NASA Astrophysics Data System (ADS)

Knuth, K. H.

2001-05-01

We consider the application of Bayesian inference to the study of self-organized structures in complex adaptive systems. In particular, we examine the distribution of elements, agents, or processes in systems dominated by hierarchical structure. We demonstrate that results obtained by Caianiello [1] on Hierarchical Modular Systems (HMS) can be found by applying Jaynes' Principle of Group Invariance [2] to a few key assumptions about our knowledge of hierarchical organization. Subsequent application of the Principle of Maximum Entropy allows inferences to be made about specific systems. The utility of the Bayesian method is considered by examining both successes and failures of the hierarchical model. We discuss how Caianiello's original statements suffer from the Mind Projection Fallacy [3] and we restate his assumptions thus widening the applicability of the HMS model. The relationship between inference and statistical physics, described by Jaynes [4], is reiterated with the expectation that this realization will aid the field of complex systems research by moving away from often inappropriate direct application of statistical mechanics to a more encompassing inferential methodology.

Global long-range transport and lung cancer risk from polycyclic aromatic hydrocarbons shielded by coatings of organic aerosol

PubMed Central

Lou, Sijia; Zelenyuk, Alla; Easter, Richard C.; Corley, Richard A.; Thrall, Brian D.; Rasch, Philip J.; Fast, Jerome D.; Massey Simonich, Staci L.; Tao, Shu

2017-01-01

Polycyclic aromatic hydrocarbons (PAHs) have toxic impacts on humans and ecosystems. One of the most carcinogenic PAHs, benzo(a)pyrene (BaP), is efficiently bound to and transported with atmospheric particles. Laboratory measurements show that particle-bound BaP degrades in a few hours by heterogeneous reaction with ozone, yet field observations indicate BaP persists much longer in the atmosphere, and some previous chemical transport modeling studies have ignored heterogeneous oxidation of BaP to bring model predictions into better agreement with field observations. We attribute this unexplained discrepancy to the shielding of BaP from oxidation by coatings of viscous organic aerosol (OA). Accounting for this OA viscosity-dependent shielding, which varies with temperature and humidity, in a global climate/chemistry model brings model predictions into much better agreement with BaP measurements, and demonstrates stronger long-range transport, greater deposition fluxes, and substantially elevated lung cancer risk from PAHs. Model results indicate that the OA coating is more effective in shielding BaP in the middle/high latitudes compared with the tropics because of differences in OA properties (semisolid when cool/dry vs. liquid-like when warm/humid). Faster chemical degradation of BaP in the tropics leads to higher concentrations of BaP oxidation products over the tropics compared with higher latitudes. This study has profound implications demonstrating that OA strongly modulates the atmospheric persistence of PAHs and their cancer risks. PMID:28115713

Global long-range transport and lung cancer risk from polycyclic aromatic hydrocarbons shielded by coatings of organic aerosol

NASA Astrophysics Data System (ADS)

Shrivastava, Manish; Lou, Silja; Zelenyuk, Alla; Easter, Richard C.; Corley, Richard A.; Thrall, Brian D.; Rasch, Philip J.; Fast, Jerome D.; Massey Simonich, Staci L.; Shen, Huizhong; Tao, Shu

2017-02-01

Polycyclic aromatic hydrocarbons (PAHs) have toxic impacts on humans and ecosystems. One of the most carcinogenic PAHs, benzo(a)pyrene (BaP), is efficiently bound to and transported with atmospheric particles. Laboratory measurements show that particle-bound BaP degrades in a few hours by heterogeneous reaction with ozone, yet field observations indicate BaP persists much longer in the atmosphere, and some previous chemical transport modeling studies have ignored heterogeneous oxidation of BaP to bring model predictions into better agreement with field observations. We attribute this unexplained discrepancy to the shielding of BaP from oxidation by coatings of viscous organic aerosol (OA). Accounting for this OA viscosity-dependent shielding, which varies with temperature and humidity, in a global climate/chemistry model brings model predictions into much better agreement with BaP measurements, and demonstrates stronger long-range transport, greater deposition fluxes, and substantially elevated lung cancer risk from PAHs. Model results indicate that the OA coating is more effective in shielding BaP in the middle/high latitudes compared with the tropics because of differences in OA properties (semisolid when cool/dry vs. liquid-like when warm/humid). Faster chemical degradation of BaP in the tropics leads to higher concentrations of BaP oxidation products over the tropics compared with higher latitudes. This study has profound implications demonstrating that OA strongly modulates the atmospheric persistence of PAHs and their cancer risks.

Accelerating quality improvement within your organization: Applying the Model for Improvement.

PubMed

Crowl, Ashley; Sharma, Anita; Sorge, Lindsay; Sorensen, Todd

2015-01-01

To discuss the fundamentals of the Model for Improvement and how the model can be applied to quality improvement activities associated with medication use, including understanding the three essential questions that guide quality improvement, applying a process for actively testing change within an organization, and measuring the success of these changes on care delivery. PubMed from 1990 through April 2014 using the search terms quality improvement, process improvement, hospitals, and primary care. At the authors' discretion, studies were selected based on their relevance in demonstrating the quality improvement process and tests of change within an organization. Organizations are continuously seeking to enhance quality in patient care services, and much of this work focuses on improving care delivery processes. Yet change in these systems is often slow, which can lead to frustration or apathy among frontline practitioners. Adopting and applying the Model for Improvement as a core strategy for quality improvement efforts can accelerate the process. While the model is frequently well known in hospitals and primary care settings, it is not always familiar to pharmacists. In addition, while some organizations may be familiar with the "plan, do, study, act" (PDSA) cycles-one element of the Model for Improvement-many do not apply it effectively. The goal of the model is to combine a continuous process of small tests of change (PDSA cycles) within an overarching aim with a longitudinal measurement process. This process differs from other forms of improvement work that plan and implement large-scale change over an extended period, followed by months of data collection. In this scenario it may take months or years to determine whether an intervention will have a positive impact. By following the Model for Improvement, frontline practitioners and their organizational leaders quickly identify strategies that make a positive difference and result in a greater degree of success.

Study on the removal of organic micropollutants from aqueous and ethanol solutions by HAP membranes with tunable hydrophilicity and hydrophobicity.

PubMed

He, Junyong; Li, Yulian; Cai, Xingguo; Chen, Kai; Zheng, Hejing; Wang, Chengming; Zhang, Kaisheng; Lin, Dongyue; Kong, Lingtao; Liu, Jinhuai

2017-05-01

A biocompatible and uniquely defined hydroxyapatite (HAP) adsorption membrane with a sandwich structure was developed for the removal of organic micropollutants for the first time. Both the adsorption and membrane technique were used for the removal of organic micropollutants. The hydrophilicity and hydrophobicity of the HAP adsorbent and membrane were tunable by controlling the surface structure of HAP. The adsorption of organic micropollutants on the HAP adsorbent was studied in batch experiments. The adsorption process was fit with the Freundlich model, while the adsorption kinetics followed the pseudo-second-order model. The HAP membrane could remove organic micropollutants effectively by dynamic adsorption in both aqueous and ethanol solutions. The removal efficiencies of organic micropollutants depended on the solution composition, membrane thickness and hydrophilicity, flow rate, and the initial concentration of organic micropollutants. The adsorption capacities of the HAP membrane with a sandwich structure (membrane thickness was 0.3 mm) were 6700, 6510, 6310, 5960, 5490, 5230, 4980 and 4360 L m -2 for 1-naphthyl amine, 2-naphthol, bisphenol S, propranolol hydrochloride, metolachlor, ethinyl oestradiol, 2,4-dichlorophenol and bisphenol A, respectively, when the initial concentration was 3.0 mg L -1 . The biocompatible HAP adsorption membrane can be easily regenerated by methanol and was thus demonstrated to be a novel concept for the removal of organic micropollutants from both aqueous and organic solutions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Morphometric analysis of abdominal organs and rib cage: Implication for risk of solid organ injuries in children.

PubMed

Harbaugh, Calista M; Shlykov, Maksim A; Tsuchida, Ryan E; Holcombe, Sven A; Hirschl, Jake; Wang, Stewart C; Ehrlich, Peter F

2015-06-01

Motor vehicle crashes are the leading cause of injury-related mortality in children, with a higher rate of multiorgan injuries than in adults. This may be related to increased solid organ volume relative to abdominal cavity and decreased protection of an underdeveloped cartilaginous rib cage in young children. To date, these anatomic relationships have not been fully described. Our study used analytic morphomics to obtain precise measures of the pediatric liver, spleen, kidneys, and ribs. This pilot study included 215 trauma patients (aged 0-18 years) with anonymized computed tomography (CT) scans. Liver, spleen, and kidney volumes were modeled using semiautomatic algorithms (MATLAB 2013a, MathWorks Inc., Natick, MA). Thirty-one scans were adequate to model the rib cage. Pearson's r was used to correlate absolute organ volume, fractional organ volume, and organ exposure with age and weight. Spleen, right and left kidney, and liver volumes increased with age and weight (p < 0.01). Right/left kidney and liver fractional volumes decreased with age (p < 0.01), whereas spleen fractional volume remained relatively constant. Exposed surface area of the liver only significantly decreased with age in the anterior (p < 0.01), right (p < 0.01), and posterior views (p = 0.02). With this study, we have demonstrated the ability to model solid organ and rib cage anatomy of children using cross-sectional imaging. In younger children, there may be a decrease in fractional organ volume and increase in liver surface exposure, although analysis of a larger sample size is warranted. In the future, this information may be used to improve the design of safety restraints in motor vehicles.

Risk transfer modeling among hierarchically associated stakeholders in development of space systems

NASA Astrophysics Data System (ADS)

Henkle, Thomas Grove, III

Research develops an empirically derived cardinal model that prescribes handling and transfer of risks between organizations with hierarchical relationships. Descriptions of mission risk events, risk attitudes, and conditions for risk transfer are determined for client and underwriting entities associated with acquisition, production, and deployment of space systems. The hypothesis anticipates that large client organizations should be able to assume larger dollar-value risks of a program in comparison to smaller organizations even though many current risk transfer arrangements via space insurance violate this hypothesis. A literature survey covers conventional and current risk assessment methods, current techniques used in the satellite industry for complex system development, cardinal risk modeling, and relevant aspects of utility theory. Data gathered from open literature on demonstrated launch vehicle and satellite in-orbit reliability, annual space insurance premiums and losses, and ground fatalities and range damage associated with satellite launch activities are presented. Empirically derived models are developed for risk attitudes of space system clients and third-party underwriters associated with satellite system development and deployment. Two application topics for risk transfer are examined: the client-underwriter relationship on assumption or transfer of risks associated with first-year mission success, and statutory risk transfer agreements between space insurance underwriters and the US government to promote growth in both commercial client and underwriting industries. Results indicate that client entities with wealth of at least an order of magnitude above satellite project costs should retain risks to first-year mission success despite present trends. Furthermore, large client entities such as the US government should never pursue risk transfer via insurance under previously demonstrated probabilities of mission success; potential savings may reasonably exceed multiple tens of $millions per space project. Additional results indicate that current US government statutory arrangements on risk sharing with underwriting entities appears reasonable with respect to stated objectives. This research combines aspects of multiple disciplines to include risk management, decision theory, utility theory, and systems architecting. It also demonstrates development of a more general theory on prescribing risk transfer criteria between distinct, but hierarchically associated entities involved in complex system development with applicability to a variety of technical domains.

Evaluating nephrotoxicity of high-molecular-weight organic compounds in drinking water from lignite aquifers

USGS Publications Warehouse

Bunnell, J.E.; Tatu, C.A.; Lerch, H.E.; Orem, W.H.; Pavlovic, N.

2007-01-01

High-molecular-weight organic compounds such as humic acids and/or fulvic acids that are naturally mobilized from lignite beds into untreated drinking-water supplies were suggested as one possible cause of Balkan endemic nephropathy (BEN) and cancer of the renal pelvis. A lab investigation was undertaken in order to assess the nephrotoxic potential of such organic compounds using an in vitro tissue culture model. Because of the infeasibility of exposing kidney tissue to low concentrations of organics for years in the lab, tangential flow ultrafiltration was employed to hyperconcentrate samples suitable for discerning effects in the short time frames necessitated by tissue culture systems. Effects on HK-2 kidney cells were measured using two different cell proliferation assays (MTT and alamarBlue). Results demonstrated that exposure of kidney tissue to high-molecular-weight organics produced excess cell death or proliferation depending on concentration and duration of exposure. Copyright ?? Taylor & Francis Group, LLC.

Combination of Metabolomic and Proteomic Analysis Revealed Different Features among Lactobacillus delbrueckii Subspecies bulgaricus and lactis Strains While In Vivo Testing in the Model Organism Caenorhabditis elegans Highlighted Probiotic Properties

PubMed Central

Zanni, Elena; Schifano, Emily; Motta, Sara; Sciubba, Fabio; Palleschi, Claudio; Mauri, Pierluigi; Perozzi, Giuditta; Uccelletti, Daniela; Devirgiliis, Chiara; Miccheli, Alfredo

2017-01-01

Lactobacillus delbrueckii represents a technologically relevant member of lactic acid bacteria, since the two subspecies bulgaricus and lactis are widely associated with fermented dairy products. In the present work, we report the characterization of two commercial strains belonging to L. delbrueckii subspecies bulgaricus, lactis and a novel strain previously isolated from a traditional fermented fresh cheese. A phenomic approach was performed by combining metabolomic and proteomic analysis of the three strains, which were subsequently supplemented as food source to the model organism Caenorhabditis elegans, with the final aim to evaluate their possible probiotic effects. Restriction analysis of 16S ribosomal DNA revealed that the novel foodborne strain belonged to L. delbrueckii subspecies lactis. Proteomic and metabolomic approaches showed differences in folate, aminoacid and sugar metabolic pathways among the three strains. Moreover, evaluation of C. elegans lifespan, larval development, brood size, and bacterial colonization capacity demonstrated that L. delbrueckii subsp. bulgaricus diet exerted beneficial effects on nematodes. On the other hand, both L. delbrueckii subsp. lactis strains affected lifespan and larval development. We have characterized three strains belonging to L. delbrueckii subspecies bulgaricus and lactis highlighting their divergent origin. In particular, the two closely related isolates L. delbrueckii subspecies lactis display different galactose metabolic capabilities. Moreover, the L. delbrueckii subspecies bulgaricus strain demonstrated potential probiotic features. Combination of omic platforms coupled with in vivo screening in the simple model organism C. elegans is a powerful tool to characterize industrially relevant bacterial isolates. PMID:28702021

Combination of Metabolomic and Proteomic Analysis Revealed Different Features among Lactobacillus delbrueckii Subspecies bulgaricus and lactis Strains While In Vivo Testing in the Model Organism Caenorhabditis elegans Highlighted Probiotic Properties.

PubMed

Zanni, Elena; Schifano, Emily; Motta, Sara; Sciubba, Fabio; Palleschi, Claudio; Mauri, Pierluigi; Perozzi, Giuditta; Uccelletti, Daniela; Devirgiliis, Chiara; Miccheli, Alfredo

2017-01-01

Lactobacillus delbrueckii represents a technologically relevant member of lactic acid bacteria, since the two subspecies bulgaricus and lactis are widely associated with fermented dairy products. In the present work, we report the characterization of two commercial strains belonging to L. delbrueckii subspecies bulgaricus , lactis and a novel strain previously isolated from a traditional fermented fresh cheese. A phenomic approach was performed by combining metabolomic and proteomic analysis of the three strains, which were subsequently supplemented as food source to the model organism Caenorhabditis elegans , with the final aim to evaluate their possible probiotic effects. Restriction analysis of 16S ribosomal DNA revealed that the novel foodborne strain belonged to L. delbrueckii subspecies lactis . Proteomic and metabolomic approaches showed differences in folate, aminoacid and sugar metabolic pathways among the three strains. Moreover, evaluation of C. elegans lifespan, larval development, brood size, and bacterial colonization capacity demonstrated that L. delbrueckii subsp. bulgaricus diet exerted beneficial effects on nematodes. On the other hand, both L. delbrueckii subsp. lactis strains affected lifespan and larval development. We have characterized three strains belonging to L. delbrueckii subspecies bulgaricus and lactis highlighting their divergent origin. In particular, the two closely related isolates L. delbrueckii subspecies lactis display different galactose metabolic capabilities. Moreover, the L. delbrueckii subspecies bulgaricus strain demonstrated potential probiotic features. Combination of omic platforms coupled with in vivo screening in the simple model organism C. elegans is a powerful tool to characterize industrially relevant bacterial isolates.

Perceptual integration of kinematic components in the recognition of emotional facial expressions.

PubMed

Chiovetto, Enrico; Curio, Cristóbal; Endres, Dominik; Giese, Martin

2018-04-01

According to a long-standing hypothesis in motor control, complex body motion is organized in terms of movement primitives, reducing massively the dimensionality of the underlying control problems. For body movements, this low-dimensional organization has been convincingly demonstrated by the learning of low-dimensional representations from kinematic and EMG data. In contrast, the effective dimensionality of dynamic facial expressions is unknown, and dominant analysis approaches have been based on heuristically defined facial "action units," which reflect contributions of individual face muscles. We determined the effective dimensionality of dynamic facial expressions by learning of a low-dimensional model from 11 facial expressions. We found an amazingly low dimensionality with only two movement primitives being sufficient to simulate these dynamic expressions with high accuracy. This low dimensionality is confirmed statistically, by Bayesian model comparison of models with different numbers of primitives, and by a psychophysical experiment that demonstrates that expressions, simulated with only two primitives, are indistinguishable from natural ones. In addition, we find statistically optimal integration of the emotion information specified by these primitives in visual perception. Taken together, our results indicate that facial expressions might be controlled by a very small number of independent control units, permitting very low-dimensional parametrization of the associated facial expression.

Disease phenotype of a ferret CFTR-knockout model of cystic fibrosis

PubMed Central

Sun, Xingshen; Sui, Hongshu; Fisher, John T.; Yan, Ziying; Liu, Xiaoming; Cho, Hyung-Ju; Joo, Nam Soo; Zhang, Yulong; Zhou, Weihong; Yi, Yaling; Kinyon, Joann M.; Lei-Butters, Diana C.; Griffin, Michelle A.; Naumann, Paul; Luo, Meihui; Ascher, Jill; Wang, Kai; Frana, Timothy; Wine, Jeffrey J.; Meyerholz, David K.; Engelhardt, John F.

2010-01-01

Cystic fibrosis (CF) is a recessive disease that affects multiple organs. It is caused by mutations in CFTR. Animal modeling of this disease has been challenging, with species- and strain-specific differences in organ biology and CFTR function influencing the emergence of disease pathology. Here, we report the phenotype of a CFTR-knockout ferret model of CF. Neonatal CFTR-knockout ferrets demonstrated many of the characteristics of human CF disease, including defective airway chloride transport and submucosal gland fluid secretion; variably penetrant meconium ileus (MI); pancreatic, liver, and vas deferens disease; and a predisposition to lung infection in the early postnatal period. Severe malabsorption by the gastrointestinal (GI) tract was the primary cause of death in CFTR-knockout kits that escaped MI. Elevated liver function tests in CFTR-knockout kits were corrected by oral administration of ursodeoxycholic acid, and the addition of an oral proton-pump inhibitor improved weight gain and survival. To overcome the limitations imposed by the severe intestinal phenotype, we cloned 4 gut-corrected transgenic CFTR-knockout kits that expressed ferret CFTR specifically in the intestine. One clone passed feces normally and demonstrated no detectable ferret CFTR expression in the lung or liver. The animals described in this study are likely to be useful tools for dissecting CF disease pathogenesis and developing treatments. PMID:20739752

Disease phenotype of a ferret CFTR-knockout model of cystic fibrosis.

PubMed

Sun, Xingshen; Sui, Hongshu; Fisher, John T; Yan, Ziying; Liu, Xiaoming; Cho, Hyung-Ju; Joo, Nam Soo; Zhang, Yulong; Zhou, Weihong; Yi, Yaling; Kinyon, Joann M; Lei-Butters, Diana C; Griffin, Michelle A; Naumann, Paul; Luo, Meihui; Ascher, Jill; Wang, Kai; Frana, Timothy; Wine, Jeffrey J; Meyerholz, David K; Engelhardt, John F

2010-09-01

Cystic fibrosis (CF) is a recessive disease that affects multiple organs. It is caused by mutations in CFTR. Animal modeling of this disease has been challenging, with species- and strain-specific differences in organ biology and CFTR function influencing the emergence of disease pathology. Here, we report the phenotype of a CFTR-knockout ferret model of CF. Neonatal CFTR-knockout ferrets demonstrated many of the characteristics of human CF disease, including defective airway chloride transport and submucosal gland fluid secretion; variably penetrant meconium ileus (MI); pancreatic, liver, and vas deferens disease; and a predisposition to lung infection in the early postnatal period. Severe malabsorption by the gastrointestinal (GI) tract was the primary cause of death in CFTR-knockout kits that escaped MI. Elevated liver function tests in CFTR-knockout kits were corrected by oral administration of ursodeoxycholic acid, and the addition of an oral proton-pump inhibitor improved weight gain and survival. To overcome the limitations imposed by the severe intestinal phenotype, we cloned 4 gut-corrected transgenic CFTR-knockout kits that expressed ferret CFTR specifically in the intestine. One clone passed feces normally and demonstrated no detectable ferret CFTR expression in the lung or liver. The animals described in this study are likely to be useful tools for dissecting CF disease pathogenesis and developing treatments.

Fucoidan extracted from Fucus evanescens prevents endotoxin-induced damage in a mouse model of endotoxemia.

PubMed

Kuznetsova, Tatyana A; Besednova, Natalya N; Somova, Larisa M; Plekhova, Natalya G

2014-01-31

An important problem of treating patients with endotoxemia is to find drugs to reduce the negative effects of endotoxin on the organism. We tested fucoidan (sulfated polysaccharide) from the brown alga Fucus evanescens as a potential drug in a mouse model of endotoxemia inducted by lipopolysaccharide (LPS). The survival time of mice injected with LPS increased under fucoidan treatment compared with the group of mice injected with LPS only. The preventive administration of fucoidan to mice with endotoxemia resulted in inhibition of increased levels of proinflammatory cytokines (TNFα and IL-6), as well as decreasing of the processes of hypercoagulability. The parenteral or per os administration of fucoidan resulted in decreasing the degree of microcirculatory disorders and secondary dystrophic-destructive changes in parenchymal organs of mice with endotoxemia. Taken together, these results demonstrate that fucoidan prevents endotoxin-induced damage in a mouse model of endotoxemia and increases the mice's resistance to LPS.

Caenorhabditis elegans as Model System in Pharmacology and Toxicology: Effects of Flavonoids on Redox-Sensitive Signalling Pathways and Ageing

PubMed Central

Koch, Karoline; Havermann, Susannah; Büchter, Christian

2014-01-01

Flavonoids are secondary plant compounds that mediate diverse biological activities, for example, by scavenging free radicals and modulating intracellular signalling pathways. It has been shown in various studies that distinct flavonoid compounds enhance stress resistance and even prolong the life span of organisms. In the last years the model organism C. elegans has gained increasing importance in pharmacological and toxicological sciences due to the availability of various genetically modified nematode strains, the simplicity of modulating genes by RNAi, and the relatively short life span. Several studies have been performed demonstrating that secondary plant compounds influence ageing, stress resistance, and distinct signalling pathways in the nematode. Here we present an overview of the modulating effects of different flavonoids on oxidative stress, redox-sensitive signalling pathways, and life span in C. elegans introducing the usability of this model system for pharmacological and toxicological research. PMID:24895670

Nanopyroxene Grafting with β-Cyclodextrin Monomer for Wastewater Applications.

PubMed

Nafie, Ghada; Vitale, Gerardo; Carbognani Ortega, Lante; Nassar, Nashaat N

2017-12-06

Emerging nanoparticle technology provides opportunities for environmentally friendly wastewater treatment applications, including those in the large liquid tailings containments in the Alberta oil sands. In this study, we synthesize β-cyclodextrin grafted nanopyroxenes to offer an ecofriendly platform for the selective removal of organic compounds typically present in these types of applications. We carry out computational modeling at the micro level through molecular mechanics and molecular dynamics simulations and laboratory experiments at the macro level to understand the interactions between the synthesized nanomaterials and two-model naphthenic acid molecules (cyclopentanecarboxylic and trans-4-pentylcyclohexanecarboxylic acids) typically existing in tailing ponds. The proof-of-concept computational modeling and experiments demonstrate that monomer grafted nanopyroxene  or nano-AE of the sodium iron-silicate aegirine are found to be promising candidates for the removal of polar organic compounds from wastewater, among other applications. These nano-AE offer new possibilities for treating tailing ponds generated by the oil sands industry.

Change management in health care.

PubMed

Campbell, Robert James

2008-01-01

This article introduces health care managers to the theories and philosophies of John Kotter and William Bridges, 2 leaders in the evolving field of change management. For Kotter, change has both an emotional and situational component, and methods for managing each are expressed in his 8-step model (developing urgency, building a guiding team, creating a vision, communicating for buy-in, enabling action, creating short-term wins, don't let up, and making it stick). Bridges deals with change at a more granular, individual level, suggesting that change within a health care organization means that individuals must transition from one identity to a new identity when they are involved in a process of change. According to Bridges, transitions occur in 3 steps: endings, the neutral zone, and beginnings. The major steps and important concepts within the models of each are addressed, and examples are provided to demonstrate how health care managers can actualize the models within their health care organizations.

Ferritin L and Ferritin H are differentially located within hepatic and extra hepatic organs under physiological and acute phase conditions.

PubMed

Ahmad, Shakil; Moriconi, Federico; Naz, Naila; Sultan, Sadaf; Sheikh, Nadeem; Ramadori, Giuliano; Malik, Ihtzaz Ahmed

2013-01-01

Ferritin L (FTL) and Ferritin H (FTH) subunits are responsible for intercellular iron storage. We previously reported increasing amounts of liver cytoplasmic and nuclear iron content during acute phase response (APR). Aim of the present study is to demonstrate intracellular localization of ferritin subunits in liver compared with extra hepatic organs of rat under physiological and acute phase conditions. Rats were administered turpentine-oil (TO) intramuscularly to induce a sterile abscess (acute-phase-model) and sacrificed at different time points. Immunohistochemistry was performed utilizing horse-reddish-peroxidise conjugated secondary antibody on 4μm thick section. Liver cytoplasmic and nuclear protein were used for Western blot analysis. By means of immunohistology, FTL was detected in cytoplasm while a strong nuclear positivity for FTH was evident in the liver. Similarly, in heart, spleen and brain FTL was detected mainly in the cytoplasm while FTH demonstrated intense nuclear and a weak cytoplasmic expression. Western blot analysis of cytoplasmic and nuclear fractions from liver, heart, spleen and brain further confirmed mainly cytoplasmic expression of FTL in contrast to the nuclear and cytoplasmic expression of FTH. The data presented demonstrate the differential localization of FTL and FTH within hepatic and extra hepatic organs being FTL predominantly in the cytoplasm while FTH predominantly in nucleus.

Chronic effects of losartan on the muscles and the serologic profiles of mdx mice.

PubMed

Lee, Eun-Mi; Kim, Dae-Yong; Kim, Ah-Young; Lee, Eun-Joo; Kim, Sang-Hyeob; Lee, Myeong-Mi; Sung, Soo-Eun; Park, Jin-Kyu; Jeong, Kyu-Shik

2015-12-15

Losartan, an angiotensin II type 1 receptor blocker, attenuates transforming growth factor-β (TGF-β) signaling, which inhibits myogenic regeneration. Although many researchers have demonstrated that losartan has anti-fibrotic and protective effects on cardiac and skeletal muscles, for long-term administration to treat dystrophic disorders, it is essential to demonstrate not only the therapeutic effects of losartan on muscles but also its effects on other organs and on blood biochemistry. Mdx mice, an animal model of Duchenne muscular dystrophy (DMD), were fed losartan dissolved in tap water. After 44weeks, the skeletal (gastrocnemius), cardiac, and diaphragm muscles of mdx mice were removed. Tissue and blood samples were collected from all experimental animals. Effects of losartan on muscle regeneration, fibrosis, and blood enzymatic profiles were evaluated. In histopathological findings and serum biochemistry analyses, chronic losartan administration showed muscular protective effects and inhibited fibrosis in skeletal (gastrocnemius), cardiac, and diaphragmatic muscles. In addition, losartan had no effects on other solid organs. Interestingly, losartan had beneficial effects on serum HDL ratio. This study demonstrates the therapeutic effects of losartan on muscles and its effects on other organs and on blood biochemistry. In conclusion, our results provide useful information for consideration of chronic losartan administration be as a treatment of DMD. Copyright © 2015 Elsevier Inc. All rights reserved.

Technical note: Relating functional group measurements to carbon types for improved model-measurement comparisons of organic aerosol composition

NASA Astrophysics Data System (ADS)

Takahama, Satoshi; Ruggeri, Giulia

2017-04-01

Functional group (FG) analysis provides a means by which functionalization in organic aerosol can be attributed to the abundances of its underlying molecular structures. However, performing this attribution requires additional, unobserved details about the molecular mixture to provide constraints in the estimation process. We present an approach for conceptualizing FG measurements of organic aerosol in terms of its functionalized carbon atoms. This reformulation facilitates estimation of mass recovery and biases in popular carbon-centric metrics that describe the extent of functionalization (such as oxygen to carbon ratio, organic mass to organic carbon mass ratio, and mean carbon oxidation state) for any given set of molecules and FGs analyzed. Furthermore, this approach allows development of parameterizations to more precisely estimate the organic carbon content from measured FG abundance. We use simulated photooxidation products of α-pinene secondary organic aerosol previously reported by Ruggeri et al. (2016) and FG measurements by Fourier transform infrared (FT-IR) spectroscopy in chamber experiments by Sax et al. (2005) to infer the relationships among molecular composition, FG composition, and metrics of organic aerosol functionalization. We find that for this simulated system, ˜ 80 % of the carbon atoms should be detected by FGs for which calibration models are commonly developed, and ˜ 7 % of the carbon atoms are undetectable by FT-IR analysis because they are not associated with vibrational modes in the infrared. Estimated biases due to undetected carbon fraction for these simulations are used to make adjustments in these carbon-centric metrics such that model-measurement differences are framed in terms of unmeasured heteroatoms (e.g., in hydroperoxide and nitrate groups for the case studied in this demonstration). The formality of this method provides framework for extending FG analysis to not only model-measurement but also instrument intercomparisons in other chemical systems.

Advanced age diminishes tendon-to-bone healing in a rat model of rotator cuff repair.

PubMed

Plate, Johannes F; Brown, Philip J; Walters, Jordan; Clark, John A; Smith, Thomas L; Freehill, Michael T; Tuohy, Christopher J; Stitzel, Joel D; Mannava, Sandeep

2014-04-01

Advanced patient age is associated with recurrent tearing and failure of rotator cuff repairs clinically; however, basic science studies have not evaluated the influence of aging on tendon-to-bone healing after rotator cuff repair in an animal model. Hypothesis/ This study examined the effect of aging on tendon-to-bone healing in an established rat model of rotator cuff repair using the aged animal colony from the National Institute on Aging of the National Institutes of Health. The authors hypothesized that normal aging decreases biomechanical strength and histologic organization at the tendon-to-bone junction after acute repair. Controlled laboratory study. In 56 F344xBN rats, 28 old and 28 young (24 and 8 months of age, respectively), the supraspinatus tendon was transected and repaired. At 2 or 8 weeks after surgery, shoulder specimens underwent biomechanical testing to compare load-to-failure and load-relaxation response between age groups. Histologic sections of the tendon-to-bone interface were assessed with hematoxylin and eosin staining, and collagen fiber organization was assessed by semiquantitative analysis of picrosirius red birefringence under polarized light. Peak failure load was similar between young and old animals at 2 weeks after repair (31% vs 26% of age-matched uninjured controls, respectively; P > .05) but significantly higher in young animals compared with old animals 8 weeks after repair (86% vs 65% of age-matched uninjured controls, respectively; P < .01). Eight weeks after repair, fibroblasts appeared more organized and uniformly aligned in young animals on hematoxylin and eosin slides compared with old animals. Collagen birefringence analysis of the tendon-to-bone junction demonstrated that young animals had increased collagen fiber organization and similar histologic structure compared with age-matched controls (53.7 ± 2.4 gray scales; P > .05). In contrast, old animals had decreased collagen fiber organization and altered structure compared with age-matched controls (49.8 ± 3.1 gray scales; P < .01). In a rat model of aging, old animals demonstrated diminished tendon-to-bone healing after rotator cuff injury and repair. Old animals had significantly decreased failure strength and collagen fiber organization at the tendon-to-bone junction compared with young animals. This study implies that animal age may need to be considered in future studies of rotator cuff repair in animal models. With increasing age and activity level of the population, the incidence of rotator cuff tears is predicted to rise. Despite advances in rotator cuff repair technique, the retear rate remains specifically high in elderly patients. The findings of this research suggest that aging negatively influences tendon-to-bone healing after rotator cuff repair in a validated animal model.

Some Physical Principles Governing Spatial and Temporal Organization in Living Systems

NASA Astrophysics Data System (ADS)

Ali, Md Zulfikar

Spatial and temporal organization in living organisms are crucial for a variety of biological functions and arise from the interplay of large number of interacting molecules. One of the central questions in systems biology is to understand how such an intricate organization emerges from the molecular biochemistry of the cell. In this dissertation we explore two projects. The first project relates to pattern formation in a cell membrane as an example of spatial organization, and the second project relates to the evolution of oscillatory networks as a simple example of temporal organization. For the first project, we introduce a model for pattern formation in a two-component lipid bilayer and study the interplay between membrane composition and membrane geometry, demonstrating the existence of a rich phase diagram. Pattern formation is governed by the interplay between phase separation driven by lipid-lipid interactions and tendency of lipid domains with high intrinsic curvature to deform the membrane away from its preferred position. Depending on membrane parameters, we find the formation of compact lipid micro-clusters or of striped domains. We calculate the stripe width analytically and find good agreement with stripe widths obtained from the simulations. For the second project, we introduce a minimal model for the evolution of functional protein-interaction networks using a sequence-based mutational algorithm and apply it to study the following problems. Using the model, we study robustness and designabilty of a 2-component network that generate oscillations. We completely enumerate the sequence space and the phenotypic space, and discuss the relationship between designabilty, robustness and evolvability. We further apply the model to studies of neutral drift in networks that yield oscillatory dynamics, e.g. starting with a relatively simple network and allowing it to evolve by adding nodes and connections while requiring that oscillatory dynamics be preserved. Our studies demonstrate both the importance of employing a sequence-based evolutionary scheme and the relative rapidity (in evolutionary time) for the redistribution of function over new nodes via neutral drift. In addition we discovered another much slower timescale for network evolution, reflecting hidden order in sequence space that we interpret in terms of sparsely connected domains. Finally, we use the model to study the evolution of an oscillator from a non-oscillatory network under the influence of external periodic forcing as a model for evolution of circadian rhythm in living systems. We use a greedy algorithm based on optimizing biologically motivated fitness functions and find that the algorithm successfully produces oscillators. However, the distribution of free-period of evolved oscillators depends on the choice of fitness functions and the nature of forcing.

Study of Adsorption and Desorption Performances of Zr-Based Metal–Organic Frameworks Using Paper Spray Mass Spectrometry

PubMed Central

Wang, Xiaoting; Chen, Ying; Zheng, Yajun

2017-01-01

The dynamic pore systems and high surface areas of flexible metal–organic framework materials make them excellent candidates to be used in different kinds of adsorption processes. However, the adsorption and desorption behaviors of therapeutic drugs on metal–organic frameworks in solution are not fully developed. Here, we systematically investigated the adsorption and desorption behaviors of a typical therapeutic drug, verapamil, over several Zr-based metal–organic frameworks [e.g., Zr-FUM, UiO-66(Zr), UiO-66(Zr)-NH2 and UiO-66(Zr)-2COOH] as well as ZrO2 in an acetonitrile solution by using paper spray mass spectrometry. In contrast to other materials, UiO-66(Zr)-2COOH demonstrated a superior adsorption performance to verapamil due to their strong acid-base and/or hydrogen-bond interactions, and the adsorption process fitted well with the pseudo-second-order kinetic model. As verapamil-adsorbed materials were used for desorption experiments, ZrO2 demonstrated the most favorable desorption performance, whereas UiO-66(Zr)-2COOH yielded the poorest desorption capability. These Zr-based materials had also been coated at the surface with filter papers for the analysis of various drugs and proteins in the process of paper spray mass spectrometry. The results demonstrated that among the studied materials, ZrO2-coated paper gave the most favorable desorption performance as a pure drug solution, whereas the paper from UiO-66(Zr) demonstrated the optimal capability in the analyses of therapeutic drugs in a complex matrix (e.g., blood) and a protein (e.g., myoglobin). PMID:28773131

An efficient approach for treating composition-dependent diffusion within organic particles

DOE PAGES

O'Meara, Simon; Topping, David O.; Zaveri, Rahul A.; ...

2017-09-07

Mounting evidence demonstrates that under certain conditions the rate of component partitioning between the gas and particle phase in atmospheric organic aerosol is limited by particle-phase diffusion. To date, however, particle-phase diffusion has not been incorporated into regional atmospheric models. An analytical rather than numerical solution to diffusion through organic particulate matter is desirable because of its comparatively small computational expense in regional models. Current analytical models assume diffusion to be independent of composition and therefore use a constant diffusion coefficient. To realistically model diffusion, however, it should be composition-dependent (e.g. due to the partitioning of components that plasticise, vitrifymore » or solidify). This study assesses the modelling capability of an analytical solution to diffusion corrected to account for composition dependence against a numerical solution. Results show reasonable agreement when the gas-phase saturation ratio of a partitioning component is constant and particle-phase diffusion limits partitioning rate (<10% discrepancy in estimated radius change). However, when the saturation ratio of the partitioning component varies, a generally applicable correction cannot be found, indicating that existing methodologies are incapable of deriving a general solution. Until such time as a general solution is found, caution should be given to sensitivity studies that assume constant diffusivity. Furthermore, the correction was implemented in the polydisperse, multi-process Model for Simulating Aerosol Interactions and Chemistry (MOSAIC) and is used to illustrate how the evolution of number size distribution may be accelerated by condensation of a plasticising component onto viscous organic particles.« less

An efficient approach for treating composition-dependent diffusion within organic particles

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Meara, Simon; Topping, David O.; Zaveri, Rahul A.

Mounting evidence demonstrates that under certain conditions the rate of component partitioning between the gas and particle phase in atmospheric organic aerosol is limited by particle-phase diffusion. To date, however, particle-phase diffusion has not been incorporated into regional atmospheric models. An analytical rather than numerical solution to diffusion through organic particulate matter is desirable because of its comparatively small computational expense in regional models. Current analytical models assume diffusion to be independent of composition and therefore use a constant diffusion coefficient. To realistically model diffusion, however, it should be composition-dependent (e.g. due to the partitioning of components that plasticise, vitrifymore » or solidify). This study assesses the modelling capability of an analytical solution to diffusion corrected to account for composition dependence against a numerical solution. Results show reasonable agreement when the gas-phase saturation ratio of a partitioning component is constant and particle-phase diffusion limits partitioning rate (<10% discrepancy in estimated radius change). However, when the saturation ratio of the partitioning component varies, a generally applicable correction cannot be found, indicating that existing methodologies are incapable of deriving a general solution. Until such time as a general solution is found, caution should be given to sensitivity studies that assume constant diffusivity. Furthermore, the correction was implemented in the polydisperse, multi-process Model for Simulating Aerosol Interactions and Chemistry (MOSAIC) and is used to illustrate how the evolution of number size distribution may be accelerated by condensation of a plasticising component onto viscous organic particles.« less

NOX2 protects against progressive lung injury and multiple organ dysfunction syndrome.

PubMed

Whitmore, Laura C; Goss, Kelli L; Newell, Elizabeth A; Hilkin, Brieanna M; Hook, Jessica S; Moreland, Jessica G

2014-07-01

Systemic inflammatory response syndrome (SIRS) is a common clinical condition in patients in intensive care units that can lead to complications, including multiple organ dysfunction syndrome (MODS). MODS carries a high mortality rate, and it is unclear why some patients resolve SIRS, whereas others develop MODS. Although oxidant stress has been implicated in the development of MODS, several recent studies have demonstrated a requirement for NADPH oxidase 2 (NOX2)-derived oxidants in limiting inflammation. We recently demonstrated that NOX2 protects against lung injury and mortality in a murine model of SIRS. In the present study, we investigated the role of NOX2-derived oxidants in the progression from SIRS to MODS. Using a murine model of sterile systemic inflammation, we observed significantly greater illness and subacute mortality in gp91(phox-/y) (NOX2-deficient) mice compared with wild-type mice. Cellular analysis revealed continued neutrophil recruitment to the peritoneum and lungs of the NOX2-deficient mice and altered activation states of both neutrophils and macrophages. Histological examination showed multiple organ pathology indicative of MODS in the NOX2-deficient mice, and several inflammatory cytokines were elevated in lungs of the NOX2-deficient mice. Overall, these data suggest that NOX2 function protects against the development of MODS and is required for normal resolution of systemic inflammation. Copyright © 2014 the American Physiological Society.

Nonrigid liver registration for image-guided surgery using partial surface data: a novel iterative approach

NASA Astrophysics Data System (ADS)

Rucker, D. Caleb; Wu, Yifei; Ondrake, Janet E.; Pheiffer, Thomas S.; Simpson, Amber L.; Miga, Michael I.

2013-03-01

In the context of open abdominal image-guided liver surgery, the efficacy of an image-guidance system relies on its ability to (1) accurately depict tool locations with respect to the anatomy, and (2) maintain the work flow of the surgical team. Laser-range scanned (LRS) partial surface measurements can be taken intraoperatively with relatively little impact on the surgical work flow, as opposed to other intraoperative imaging modalities. Previous research has demonstrated that this kind of partial surface data may be (1) used to drive a rigid registration of the preoperative CT image volume to intraoperative patient space, and (2) extrapolated and combined with a tissue-mechanics-based organ model to drive a non-rigid registration, thus compensating for organ deformations. In this paper we present a novel approach for intraoperative nonrigid liver registration which iteratively reconstructs a displacement field on the posterior side of the organ in order to minimize the error between the deformed model and the intraopreative surface data. Experimental results with a phantom liver undergoing large deformations demonstrate that this method achieves target registration errors (TRE) with a mean of 4.0 mm in the prediction of a set of 58 locations inside the phantom, which represents a 50% improvement over rigid registration alone, and a 44% improvement over the prior non-iterative single-solve method of extrapolating boundary conditions via a surface Laplacian.

Allometric Scaling and Cell Ratios in Multi-Organ in vitro Models of Human Metabolism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ucciferri, Nadia; Interdepartmental Research Center “E. Piaggio”, University of Pisa, Pisa; Sbrana, Tommaso

2014-12-17

Intelligent in vitro models able to recapitulate the physiological interactions between tissues in the body have enormous potential as they enable detailed studies on specific two-way or higher order tissue communication. These models are the first step toward building an integrated picture of systemic metabolism and signaling in physiological or pathological conditions. However, the rational design of in vitro models of cell–cell or cell–tissue interaction is difficult as quite often cell culture experiments are driven by the device used, rather than by design considerations. Indeed, very little research has been carried out on in vitro models of metabolism connecting differentmore » cell or tissue types in a physiologically and metabolically relevant manner. Here, we analyze the physiological relationship between cells, cell metabolism, and exchange in the human body using allometric rules, downscaling them to an organ-on-a-plate device. In particular, in order to establish appropriate cell ratios in the system in a rational manner, two different allometric scaling models (cell number scaling model and metabolic and surface scaling model) are proposed and applied to a two compartment model of hepatic-vascular metabolic cross-talk. The theoretical scaling studies illustrate that the design and hence relevance of multi-organ models is principally determined by experimental constraints. Two experimentally feasible model configurations are then implemented in a multi-compartment organ-on-a-plate device. An analysis of the metabolic response of the two configurations demonstrates that their glucose and lipid balance is quite different, with only one of the two models recapitulating physiological-like homeostasis. In conclusion, not only do cross-talk and physical stimuli play an important role in in vitro models, but the numeric relationship between cells is also crucial to recreate in vitro interactions, which can be extrapolated to the in vivo reality.« less

Allometric Scaling and Cell Ratios in Multi-Organ in vitro Models of Human Metabolism.

PubMed

Ucciferri, Nadia; Sbrana, Tommaso; Ahluwalia, Arti

2014-01-01

Intelligent in vitro models able to recapitulate the physiological interactions between tissues in the body have enormous potential as they enable detailed studies on specific two-way or higher order tissue communication. These models are the first step toward building an integrated picture of systemic metabolism and signaling in physiological or pathological conditions. However, the rational design of in vitro models of cell-cell or cell-tissue interaction is difficult as quite often cell culture experiments are driven by the device used, rather than by design considerations. Indeed, very little research has been carried out on in vitro models of metabolism connecting different cell or tissue types in a physiologically and metabolically relevant manner. Here, we analyze the physiological relationship between cells, cell metabolism, and exchange in the human body using allometric rules, downscaling them to an organ-on-a-plate device. In particular, in order to establish appropriate cell ratios in the system in a rational manner, two different allometric scaling models (cell number scaling model and metabolic and surface scaling model) are proposed and applied to a two compartment model of hepatic-vascular metabolic cross-talk. The theoretical scaling studies illustrate that the design and hence relevance of multi-organ models is principally determined by experimental constraints. Two experimentally feasible model configurations are then implemented in a multi-compartment organ-on-a-plate device. An analysis of the metabolic response of the two configurations demonstrates that their glucose and lipid balance is quite different, with only one of the two models recapitulating physiological-like homeostasis. In conclusion, not only do cross-talk and physical stimuli play an important role in in vitro models, but the numeric relationship between cells is also crucial to recreate in vitro interactions, which can be extrapolated to the in vivo reality.

A retrospective review of how nonconformities are expressed and finalized in external inspections of health-care facilities.

PubMed

Hovlid, Einar; Høifødt, Helge; Smedbråten, Bente; Braut, Geir Sverre

2015-09-23

External inspections are widely used in health care as a means of improving the quality of care. However, the way external inspections affect the involved organization is poorly understood. A better understanding of these processes is important to improve our understanding of the varying effects of external inspections in different organizations. In turn, this can contribute to the development of more effective ways of conducting inspections. The way the inspecting organization states their grounds for noncompliant behavior and subsequently follows up to enforce the necessary changes can have implications for the inspected organization's change process. We explore how inspecting organizations express and state their grounds for noncompliant behavior and how they follow up to enforce improvements. We conducted a retrospective review, in which we performed a content analysis of the documents from 36 external inspections in Norway. Our analysis was guided by Donabedian's structure, process, and outcome model. Deficiencies in the management system in combination with clinical work processes was considered as nonconformity by the inspecting organizations. Two characteristic patterns were identified in the way observations led to a statement of nonconformity: one in which it was clearly demonstrated how deficiencies in the management system could affect clinical processes, and one in which this connection was not demonstrated. Two characteristic patterns were also identified in the way the inspecting organization followed up and finalized their inspection: one in which the inspection was finalized solely based on the documented changes in structural deficiencies addressed in the nonconformity statement, and one based on the documented changes in structural and process deficiencies addressed in the nonconformity statement. External inspections are performed to improve the quality of care. To accomplish this aim, we suggest that nonconformities should be grounded by observations that clearly demonstrate how deficiencies in the management system might affect the clinical processes, and that the inspection should be finalized based on documented changes in both structural and process deficiencies addressed in the nonconformity statement.

Modelling the 13C and 12C isotopes of inorganic and organic carbon in the Baltic Sea

NASA Astrophysics Data System (ADS)

Gustafsson, Erik; Mörth, Carl-Magnus; Humborg, Christoph; Gustafsson, Bo G.

2015-08-01

In this study, 12C and 13C contents of all carbon containing state variables (dissolved inorganic and organic carbon, detrital carbon, and the carbon content of autotrophs and heterotrophs) have for the first time been explicitly included in a coupled physical-biogeochemical Baltic Sea model. Different processes in the carbon cycling have distinct fractionation values, resulting in specific isotopic fingerprints. Thus, in addition to simulating concentrations of different tracers, our new model formulation improves the possibility to constrain the rates of processes such as CO2 assimilation, mineralization, and air-sea exchange. We demonstrate that phytoplankton production and respiration, and the related air-sea CO2 fluxes, are to a large degree controlling the isotopic composition of organic and inorganic carbon in the system. The isotopic composition is further, but to a lesser extent, influenced by river loads and deep water inflows as well as transformation of terrestrial organic carbon within the system. Changes in the isotopic composition over the 20th century have been dominated by two processes - the preferential release of 12C to the atmosphere in association with fossil fuel burning, and the eutrophication of the Baltic Sea related to increased nutrient loads under the second half of the century.

Establishing an operational waterhole monitoring system using satellite data and hydrologic modelling: Application in the pastoral regions of East Africa

USGS Publications Warehouse

Senay, Gabriel B.; Velpuri, Naga Manohar; Alemu, Henok; Pervez, Shahriar Md; Asante, Kwabena O; Karuki, Gatarwa; Taa, Asefa; Angerer, Jay

2013-01-01

Timely information on the availability of water and forage is important for the sustainable development of pastoral regions. The lack of such information increases the dependence of pastoral communities on perennial sources, which often leads to competition and conflicts. The provision of timely information is a challenging task, especially due to the scarcity or non-existence of conventional station-based hydrometeorological networks in the remote pastoral regions. A multi-source water balance modelling approach driven by satellite data was used to operationally monitor daily water level fluctuations across the pastoral regions of northern Kenya and southern Ethiopia. Advanced Spaceborne Thermal Emission and Reflection Radiometer data were used for mapping and estimating the surface area of the waterholes. Satellite-based rainfall, modelled run-off and evapotranspiration data were used to model daily water level fluctuations. Mapping of waterholes was achieved with 97% accuracy. Validation of modelled water levels with field-installed gauge data demonstrated the ability of the model to capture the seasonal patterns and variations. Validation results indicate that the model explained 60% of the observed variability in water levels, with an average root-mean-squared error of 22%. Up-to-date information on rainfall, evaporation, scaled water depth and condition of the waterholes is made available daily in near-real time via the Internet (http://watermon.tamu.edu). Such information can be used by non-governmental organizations, governmental organizations and other stakeholders for early warning and decision making. This study demonstrated an integrated approach for establishing an operational waterhole monitoring system using multi-source satellite data and hydrologic modelling.

Reactive transport modeling of geochemical controls on secondary water quality impacts at a crude oil spill site near Bemidji, MN

USGS Publications Warehouse

Ng, Gene-Hua Crystal.; Bekins, Barbara A.; Cozzarelli, Isabelle M.; Baedecker, Mary Jo; Bennett, Philip C.; Amos, Richard T.; Herkelrath, William N.

2015-01-01

Anaerobic biodegradation of organic amendments and contaminants in aquifers can trigger secondary water quality impacts that impair groundwater resources. Reactive transport models help elucidate how diverse geochemical reactions control the spatiotemporal evolution of these impacts. Using extensive monitoring data from a crude oil spill site near Bemidji, Minnesota (USA), we implemented a comprehensive model that simulates secondary plumes of depleted dissolved O2 and elevated concentrations of Mn2+, Fe2+, CH4, and Ca2+ over a two-dimensional cross section for 30 years following the spill. The model produces observed changes by representing multiple oil constituents and coupled carbonate and hydroxide chemistry. The model includes reactions with carbonates and Fe and Mn mineral phases, outgassing of CH4 and CO2 gas phases, and sorption of Fe, Mn, and H+. Model results demonstrate that most of the carbon loss from the oil (70%) occurs through direct outgassing from the oil source zone, greatly limiting the amount of CH4 cycled down-gradient. The vast majority of reduced Fe is strongly attenuated on sediments, with most (91%) in the sorbed form in the model. Ferrous carbonates constitute a small fraction of the reduced Fe in simulations, but may be important for furthering the reduction of ferric oxides. The combined effect of concomitant redox reactions, sorption, and dissolved CO2 inputs from source-zone degradation successfully reproduced observed pH. The model demonstrates that secondary water quality impacts may depend strongly on organic carbon properties, and impacts may decrease due to sorption and direct outgassing from the source zone.

Using open source computational tools for predicting human metabolic stability and additional absorption, distribution, metabolism, excretion, and toxicity properties.

PubMed

Gupta, Rishi R; Gifford, Eric M; Liston, Ted; Waller, Chris L; Hohman, Moses; Bunin, Barry A; Ekins, Sean

2010-11-01

Ligand-based computational models could be more readily shared between researchers and organizations if they were generated with open source molecular descriptors [e.g., chemistry development kit (CDK)] and modeling algorithms, because this would negate the requirement for proprietary commercial software. We initially evaluated open source descriptors and model building algorithms using a training set of approximately 50,000 molecules and a test set of approximately 25,000 molecules with human liver microsomal metabolic stability data. A C5.0 decision tree model demonstrated that CDK descriptors together with a set of Smiles Arbitrary Target Specification (SMARTS) keys had good statistics [κ = 0.43, sensitivity = 0.57, specificity = 0.91, and positive predicted value (PPV) = 0.64], equivalent to those of models built with commercial Molecular Operating Environment 2D (MOE2D) and the same set of SMARTS keys (κ = 0.43, sensitivity = 0.58, specificity = 0.91, and PPV = 0.63). Extending the dataset to ∼193,000 molecules and generating a continuous model using Cubist with a combination of CDK and SMARTS keys or MOE2D and SMARTS keys confirmed this observation. When the continuous predictions and actual values were binned to get a categorical score we observed a similar κ statistic (0.42). The same combination of descriptor set and modeling method was applied to passive permeability and P-glycoprotein efflux data with similar model testing statistics. In summary, open source tools demonstrated predictive results comparable to those of commercial software with attendant cost savings. We discuss the advantages and disadvantages of open source descriptors and the opportunity for their use as a tool for organizations to share data precompetitively, avoiding repetition and assisting drug discovery.

CSC attains VPP Star Demonstration status

NASA Image and Video Library

2009-12-09

CSC Inc. at NASA's John C. Space Center was presented a Voluntary Protection Programs (VPP) Star Demonstration banner by the Occupational Safety and Health administration (OSHA) during a Dec. 9 ceremony. From left, CSC Employee Safety Committee members LaSonya Pulliam (l to r), Jim Sever, Stacy Brunson, Debbie Duke, Sheliah Wilson, Fred Voss and Beth Nguyen, and CSC Program Manager Tony Lisotta received the banner. OSHA established VPP in 1982 as a proactive safety management model so organizations and their employees could be recognized for excellence in safety and health.

3D element imaging using NSECT for the detection of renal cancer: a simulation study in MCNP.

PubMed

Viana, R S; Agasthya, G A; Yoriyaz, H; Kapadia, A J

2013-09-07

This work describes a simulation study investigating the application of neutron stimulated emission computed tomography (NSECT) for noninvasive 3D imaging of renal cancer in vivo. Using MCNP5 simulations, we describe a method of diagnosing renal cancer in the body by mapping the 3D distribution of elements present in tumors using the NSECT technique. A human phantom containing the kidneys and other major organs was modeled in MCNP5. The element composition of each organ was based on values reported in literature. The two kidneys were modeled to contain elements reported in renal cell carcinoma (RCC) and healthy kidney tissue. Simulated NSECT scans were executed to determine the 3D element distribution of the phantom body. Elements specific to RCC and healthy kidney tissue were then analyzed to identify the locations of the diseased and healthy kidneys and generate tomographic images of the tumor. The extent of the RCC lesion inside the kidney was determined using 3D volume rendering. A similar procedure was used to generate images of each individual organ in the body. Six isotopes were studied in this work - (32)S, (12)C, (23)Na, (14)N, (31)P and (39)K. The results demonstrated that through a single NSECT scan performed in vivo, it is possible to identify the location of the kidneys and other organs within the body, determine the extent of the tumor within the organ, and to quantify the differences between cancer and healthy tissue-related isotopes with p ≤ 0.05. All of the images demonstrated appropriate concentration changes between the organs, with some discrepancy observed in (31)P, (39)K and (23)Na. The discrepancies were likely due to the low concentration of the elements in the tissue that were below the current detection sensitivity of the NSECT technique.

Efficiency at maximum power of a laser quantum heat engine enhanced by noise-induced coherence

NASA Astrophysics Data System (ADS)

Dorfman, Konstantin E.; Xu, Dazhi; Cao, Jianshu

2018-04-01

Quantum coherence has been demonstrated in various systems including organic solar cells and solid state devices. In this article, we report the lower and upper bounds for the performance of quantum heat engines determined by the efficiency at maximum power. Our prediction based on the canonical three-level Scovil and Schulz-Dubois maser model strongly depends on the ratio of system-bath couplings for the hot and cold baths and recovers the theoretical bounds established previously for the Carnot engine. Further, introducing a fourth level to the maser model can enhance the maximal power and its efficiency, thus demonstrating the importance of quantum coherence in the thermodynamics and operation of the heat engines beyond the classical limit.

Organ Dose-Rate Calculations for Small Mammals at Maralinga, the Nevada Test Site, Hanford and Fukushima: A Comparison of Ellipsoidal and Voxelized Dosimetric Methodologies.

PubMed

Caffrey, Emily A; Johansen, Mathew P; Higley, Kathryn A

2015-10-01

Radiological dosimetry for nonhuman biota typically relies on calculations that utilize the Monte Carlo simulations of simple, ellipsoidal geometries with internal radioactivity distributed homogeneously throughout. In this manner it is quick and easy to estimate whole-body dose rates to biota. Voxel models are detailed anatomical phantoms that were first used for calculating radiation dose to humans, which are now being extended to nonhuman biota dose calculations. However, if simple ellipsoidal models provide conservative dose-rate estimates, then the additional labor involved in creating voxel models may be unnecessary for most scenarios. Here we show that the ellipsoidal method provides conservative estimates of organ dose rates to small mammals. Organ dose rates were calculated for environmental source terms from Maralinga, the Nevada Test Site, Hanford and Fukushima using both the ellipsoidal and voxel techniques, and in all cases the ellipsoidal method yielded more conservative dose rates by factors of 1.2-1.4 for photons and 5.3 for beta particles. Dose rates for alpha-emitting radionuclides are identical for each method as full energy absorption in source tissue is assumed. The voxel procedure includes contributions to dose from organ-to-organ irradiation (shown here to comprise 2-50% of total dose from photons and 0-93% of total dose from beta particles) that is not specifically quantified in the ellipsoidal approach. Overall, the voxel models provide robust dosimetry for the nonhuman mammals considered in this study, and though the level of detail is likely extraneous to demonstrating regulatory compliance today, voxel models may nevertheless be advantageous in resolving ongoing questions regarding the effects of ionizing radiation on wildlife.

Retention prediction of highly polar ionizable solutes under gradient conditions on a mixed-mode reversed-phase and weak anion-exchange stationary phase.

PubMed

Balkatzopoulou, P; Fasoula, S; Gika, H; Nikitas, P; Pappa-Louisi, A

2015-05-29

In the present work the retention of three highly polar and ionizable solutes - uric acid, nicotinic acid and ascorbic acid - was investigated on a mixed-mode reversed-phase and weak anion-exchange (RP/WAX) stationary phase in buffered aqueous acetonitrile (ACN) mobile phases. A U-shaped retention behavior was observed for all solutes with respect to the eluent organic modifier content studied in a range of 5-95% (v/v). This retention behavior clearly demonstrates the presence of a HILIC-type retention mechanism at ACN-rich hydro-organic eluents and an RP-like retention at aqueous-rich hydro-organic eluents. Hence, this column should be promising for application under both RP and HILIC gradient elution modes. For this reason, a series of programmed elution runs were carried out with increasing (RP) and decreasing (HILIC) organic solvent concentration in the mobile phase. This dual gradient process was successfully modeled by two retention models exhibiting a quadratic or a cubic dependence of the logarithm of the solute retention factor (lnk) upon the organic modifier volume fraction (φ). It was found that both models produced by gradient retention data allow the prediction of solute retention times for both types of programmed elution on the mixed-mode column. Four, in the case of the quadratic model, or five, in the case of the cubic model, initial HILIC- and RP-type gradient runs gave satisfactory retention predictions of any similar kind elution program, even with different flow rate, with an overall error of only 2.5 or 1.7%, respectively. Copyright © 2015 Elsevier B.V. All rights reserved.

A novel redox-active metalloporphyrin reduces reactive oxygen species and inflammatory markers but does not improve marginal mass engraftment in a murine donation after circulatory death islet transplantation model

PubMed Central

Bruni, Antonio; Pepper, Andrew R.; Gala-Lopez, Boris; Pawlick, Rena; Abualhassan, Nasser; Crapo, James D.; Piganelli, Jon D.; Shapiro, A. M. James

2016-01-01

ABSTRACT Islet transplantation is a highly effective treatment for stabilizing glycemic control for select patients with type-1 diabetes. Despite improvements to clinical transplantation, single-donor transplant success has been hard to achieve routinely, necessitating increasing demands on viable organ availability. Donation after circulatory death (DCD) may be an alternative option to increase organ availability however, these organs tend to be more compromised. The use of metalloporphyrin anti-inflammatory and antioxidant (MnP) compounds previously demonstrated improved in vivo islet function in preclinical islet transplantation. However, the administration of MnP (BMX-001) in a DCD islet isolation and transplantation model has yet to be established. In this study, murine donors were subjected to a 15-min warm ischemic (WI) period prior to isolation and culture with or without MnP. Subsequent to one-hour culture, islets were assessed for in vitro viability and in vivo function. A 15-minute WI period significantly reduced islet yield, regardless of MnP-treatment relative to yields from standard isolation. MnP-treated islets did not improve islet viability compared to DCD islets alone. MnP-treatment did significantly reduce the presence of extracellular reactive oxygen species (ROS) (p < 0 .05). Marginal, syngeneic islets (200 islets) transplanted under the renal capsule exhibited similar in vivo outcomes regardless of WI or MnP-treatment. DCD islet grafts harvested 7 d post-transplant exhibited sustained TNF-α and IL-10, while MnP-treated islet-bearing grafts demonstrated reduced IL-10 levels. Taken together, 15-minute WI in murine islet isolation significantly impairs islet yield. DCD islets do indeed demonstrate in vivo function, though MnP therapy was unable to improve viability and engraftment outcomes. PMID:27220256

A novel redox-active metalloporphyrin reduces reactive oxygen species and inflammatory markers but does not improve marginal mass engraftment in a murine donation after circulatory death islet transplantation model.

PubMed

Bruni, Antonio; Pepper, Andrew R; Gala-Lopez, Boris; Pawlick, Rena; Abualhassan, Nasser; Crapo, James D; Piganelli, Jon D; Shapiro, A M James

2016-07-03

Islet transplantation is a highly effective treatment for stabilizing glycemic control for select patients with type-1 diabetes. Despite improvements to clinical transplantation, single-donor transplant success has been hard to achieve routinely, necessitating increasing demands on viable organ availability. Donation after circulatory death (DCD) may be an alternative option to increase organ availability however, these organs tend to be more compromised. The use of metalloporphyrin anti-inflammatory and antioxidant (MnP) compounds previously demonstrated improved in vivo islet function in preclinical islet transplantation. However, the administration of MnP (BMX-001) in a DCD islet isolation and transplantation model has yet to be established. In this study, murine donors were subjected to a 15-min warm ischemic (WI) period prior to isolation and culture with or without MnP. Subsequent to one-hour culture, islets were assessed for in vitro viability and in vivo function. A 15-minute WI period significantly reduced islet yield, regardless of MnP-treatment relative to yields from standard isolation. MnP-treated islets did not improve islet viability compared to DCD islets alone. MnP-treatment did significantly reduce the presence of extracellular reactive oxygen species (ROS) (p < 0 .05). Marginal, syngeneic islets (200 islets) transplanted under the renal capsule exhibited similar in vivo outcomes regardless of WI or MnP-treatment. DCD islet grafts harvested 7 d post-transplant exhibited sustained TNF-α and IL-10, while MnP-treated islet-bearing grafts demonstrated reduced IL-10 levels. Taken together, 15-minute WI in murine islet isolation significantly impairs islet yield. DCD islets do indeed demonstrate in vivo function, though MnP therapy was unable to improve viability and engraftment outcomes.

Linking soil DOC production rates and transport processes from landscapes to sub-basin scales

NASA Astrophysics Data System (ADS)

Tian, Y. Q.; Yu, Q.; Li, J.; Ye, C.

2014-12-01

Recent research rejects the traditional perspective that dissolved organic carbon (DOC) component in global carbon cycle are simply trivial, and in fact evidence demonstrates that lakes likely mediate carbon dynamics on a global scale. Riverine and estuarine carbon fluxes play a critical role in transporting and recycling carbon and nutrients, not only within watersheds but in their receiving waters. However, the underlying mechanisms that drive carbon fluxes, from land to rivers, lake and oceans, remain poorly understood. This presentation will report a research result of the scale-dependent DOC production rate in coastal watersheds and DOC transport processes in estuarine regions. We conducted a series of controlled experiments and field measurements for examining biogeochemical, biological, and geospatial variables that regulate downstream processing on global-relevant carbon fluxes. Results showed that increased temperatures and raised soil moistures accelerate decomposition rates of organic matter with significant variations between vegetation types. The measurements at meso-scale ecosystem demonstrated a good correlation to bulk concentration of DOC monitored in receiving waters at the outlets of sub-basins (R2 > 0.65). These field and experimental measurements improved the model of daily carbon exports through below-ground processes as a function of the organic matter content of surface soils, forest litter supply, and temperature. The study demonstrated a potential improvement in modeling the co-variance of CDOM and DOC with the unique terrestrial sources. This improvement indicated a significant promise for monitoring riverine and estuarine carbon flux from satellite images. The technical innovations include deployments of 1) mini-ecosystem (mesocosms) with soil as replicate controlled experiments for DOC production and leaching rates, and 2) aquatic mesocosms for co-variances of DOC and CDOM endmembers, and an instrumented incubation experiment for determining degradation rates.

Emerging contaminants--pesticides, PPCPs, microbial degradation products and natural substances as inhibitors of multixenobiotic defense in aquatic organisms.

PubMed

Smital, Tvrtko; Luckenbach, Till; Sauerborn, Roberta; Hamdoun, Amro M; Vega, Rebecca L; Epel, David

2004-08-18

The environmental presence of chemosensitizers or inhibitors of the multixenobiotic resistance (MXR) defense system in aquatic organisms could cause increase in intracellular accumulation and toxic effects of other xenobiotics normally effluxed by MXR transport proteins (P-glycoprotein (P-gps), MRPs). MXR inhibition with concomitant detrimental effects has been shown in several studies with aquatic organisms exposed to both model MXR inhibitors and environmental pollutants. The presence of MXR inhibitors has been demonstrated in environmental samples from polluted locations at concentrations that could abolish P-gp transport activity. However, it is not clear whether the inhibition observed after exposure to environmental samples is a result of saturation of MXR transport proteins by numerous substrates present in polluted waters or results from the presence of powerful MXR inhibitors. And are potent environmental MXR inhibitors natural or man-made chemicals? As a consequence of these uncertainties, no official action has been taken to monitor and control the release and presence of MXR inhibitors into aquatic environments. In this paper we present our new results addressing these critical questions. Ecotoxicological significance of MXR inhibition was supported in in vivo studies that demonstrated an increase in the production of mutagenic metabolites by mussels and an increase in the number of sea urchin embryos with apoptotic cells after exposure to model MXR inhibitors. We also demonstrated that MXR inhibitors are present among both conventional and emerging man-made pollutants: some pesticides and synthetic musk fragrances show extremely high MXR inhibitory potential at environmentally relevant concentrations. In addition, we emphasized the biological transformation of crude oil hydrocarbons into MXR inhibitors by oil-degrading bacteria, and the risk potentially caused by powerful natural MXR inhibitors produced by invasive species.

Stimuli Influencing Small Business Owner Adoption of a Software-as-a-Service Solution: A Quantitative Study

ERIC Educational Resources Information Center

Cianciotta, Michael A.

2016-01-01

Cloud computing has moved beyond the early adoption phase and recent trends demonstrate encouraging adoption rates. This utility-based computing model offers significant IT flexibility and potential for cost savings for organizations of all sizes, but may be the most attractive to small businesses because of limited capital to fund required…

Testing and Demonstrating Speaker Verification Technology in Iraqi-Arabic as Part of the Iraqi Enrollment Via Voice Authentication Project (IEVAP) in Support of the Global War on Terrorism (GWOT)

DTIC Science & Technology

2007-09-01

Australian/New Zealand English, Canadian French, Cantonese , European French, German, Italian, Japanese, Jordanian Arabic, Mandarin, Portuguese...Environment Within the congruence model, the environment “includes people, other organizations, social and economic forces, and legal constraints” [28

Organizational Analysis and Career Projections Based on a Level-of-Responsibility/Equitable Payment Model. Technical Report.

ERIC Educational Resources Information Center

Laner, Stephen; And Others

Following an explanation of the Level of Responsibility/Equitable Pay Function, its applicability is demonstrated to the analysis and to the design and redesign of organizational hierarchies. It is shown how certain common dysfuntional anomalies can be avoided by structuring an organization along the principles outlined. A technique is then…

Demonstration of a Model for the Education and Training of Spanish-Speaking Entrepreneurs. Final Report.

ERIC Educational Resources Information Center

Ramirez, Carlo; And Others

A three-month Federally sponsored program for Spanish-speaking entrepreneurs in the San Francisco area was conducted in 1975 by Amex Systems to examine successful or exemplary education and training systems for minority entrepreneurs, develop a manual for organizing new training programs, and promote the establishment of additional programs. The…

Learning and Teaching Styles in Management Education: Identifying, Analyzing, and Facilitating

ERIC Educational Resources Information Center

Provitera, Michael J.; Esendal, Esin

2008-01-01

Drawing on the learning theory of the Felder-Silverman model (2002), and the work of A.F. Grasha, this paper provides a brief review of teaching and learning styles used in management education. Professors, like students, demonstrate a number of learning styles and a professor has some responsibility to organize and present a course to satisfy…

Improving 3D Genome Reconstructions Using Orthologous and Functional Constraints

PubMed Central

Diament, Alon; Tuller, Tamir

2015-01-01

The study of the 3D architecture of chromosomes has been advancing rapidly in recent years. While a number of methods for 3D reconstruction of genomic models based on Hi-C data were proposed, most of the analyses in the field have been performed on different 3D representation forms (such as graphs). Here, we reproduce most of the previous results on the 3D genomic organization of the eukaryote Saccharomyces cerevisiae using analysis of 3D reconstructions. We show that many of these results can be reproduced in sparse reconstructions, generated from a small fraction of the experimental data (5% of the data), and study the properties of such models. Finally, we propose for the first time a novel approach for improving the accuracy of 3D reconstructions by introducing additional predicted physical interactions to the model, based on orthologous interactions in an evolutionary-related organism and based on predicted functional interactions between genes. We demonstrate that this approach indeed leads to the reconstruction of improved models. PMID:26000633

Drosophila melanogaster As a Model Organism to Study RNA Toxicity of Repeat Expansion-Associated Neurodegenerative and Neuromuscular Diseases

PubMed Central

Koon, Alex C.; Chan, Ho Yin Edwin

2017-01-01

For nearly a century, the fruit fly, Drosophila melanogaster, has proven to be a valuable tool in our understanding of fundamental biological processes, and has empowered our discoveries, particularly in the field of neuroscience. In recent years, Drosophila has emerged as a model organism for human neurodegenerative and neuromuscular disorders. In this review, we highlight a number of recent studies that utilized the Drosophila model to study repeat-expansion associated diseases (READs), such as polyglutamine diseases, fragile X-associated tremor/ataxia syndrome (FXTAS), myotonic dystrophy type 1 (DM1) and type 2 (DM2), and C9ORF72-associated amyotrophic lateral sclerosis/frontotemporal dementia (C9-ALS/FTD). Discoveries regarding the possible mechanisms of RNA toxicity will be focused here. These studies demonstrate Drosophila as an excellent in vivo model system that can reveal novel mechanistic insights into human disorders, providing the foundation for translational research and therapeutic development. PMID:28377694

Visualized analysis of mixed numeric and categorical data via extended self-organizing map.

PubMed

Hsu, Chung-Chian; Lin, Shu-Han

2012-01-01

Many real-world datasets are of mixed types, having numeric and categorical attributes. Even though difficult, analyzing mixed-type datasets is important. In this paper, we propose an extended self-organizing map (SOM), called MixSOM, which utilizes a data structure distance hierarchy to facilitate the handling of numeric and categorical values in a direct, unified manner. Moreover, the extended model regularizes the prototype distance between neighboring neurons in proportion to their map distance so that structures of the clusters can be portrayed better on the map. Extensive experiments on several synthetic and real-world datasets are conducted to demonstrate the capability of the model and to compare MixSOM with several existing models including Kohonen's SOM, the generalized SOM and visualization-induced SOM. The results show that MixSOM is superior to the other models in reflecting the structure of the mixed-type data and facilitates further analysis of the data such as exploration at various levels of granularity.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goltz, M.N.; Oxley, M.E.

Aquifer cleanup efforts at contaminated sites frequently involve operation of a system of extraction wells. It has been found that contaminant load discharged by extraction wells typically declines with time, asymptotically approaching a residual level. Such behavior could be due to rate-limited desorption of an organic contaminant from aquifer solids. An analytical model is presented which accounts for rate-limited desorption of an organic solute during cleanup of a contaminated site. Model equations are presented which describe transport of a sorbing contaminant in a converging radial flow field, with sorption described by (1) equilibrium, (2) first-order rate, and (3) Fickian diffusionmore » expressions. The model equations are solved in the Laplace domain and numerically inverted to simulate contaminant concentrations at an extraction well. A Laplace domain solution for the total contaminant mass remaining in the aquifer is also derived. It is shown that rate-limited sorption can have a significant impact upon aquifer remediation. Approximate equivalence among the various rate-limited models is also demonstrated.« less

Organ culture bioreactors--platforms to study human intervertebral disc degeneration and regenerative therapy.

PubMed

Gantenbein, Benjamin; Illien-Jünger, Svenja; Chan, Samantha C W; Walser, Jochen; Haglund, Lisbet; Ferguson, Stephen J; Iatridis, James C; Grad, Sibylle

2015-01-01

In recent decades the application of bioreactors has revolutionized the concept of culturing tissues and organs that require mechanical loading. In intervertebral disc (IVD) research, collaborative efforts of biomedical engineering, biology and mechatronics have led to the innovation of new loading devices that can maintain viable IVD organ explants from large animals and human cadavers in precisely defined nutritional and mechanical environments over extended culture periods. Particularly in spine and IVD research, these organ culture models offer appealing alternatives, as large bipedal animal models with naturally occurring IVD degeneration and a genetic background similar to the human condition do not exist. Latest research has demonstrated important concepts including the potential of homing of mesenchymal stem cells to nutritionally or mechanically stressed IVDs, and the regenerative potential of "smart" biomaterials for nucleus pulposus or annulus fibrosus repair. In this review, we summarize the current knowledge about cell therapy, injection of cytokines and short peptides to rescue the degenerating IVD. We further stress that most bioreactor systems simplify the real in vivo conditions providing a useful proof of concept. Limitations are that certain aspects of the immune host response and pain assessments cannot be addressed with ex vivo systems. Coccygeal animal disc models are commonly used because of their availability and similarity to human IVDs. Although in vitro loading environments are not identical to the human in vivo situation, 3D ex vivo organ culture models of large animal coccygeal and human lumbar IVDs should be seen as valid alternatives for screening and feasibility testing to augment existing small animal, large animal, and human clinical trial experiments.

Toughening mechanisms in bioinspired multilayered materials.

PubMed

Askarinejad, Sina; Rahbar, Nima

2015-01-06

Outstanding mechanical properties of biological multilayered materials are strongly influenced by nanoscale features in their structure. In this study, mechanical behaviour and toughening mechanisms of abalone nacre-inspired multilayered materials are explored. In nacre's structure, the organic matrix, pillars and the roughness of the aragonite platelets play important roles in its overall mechanical performance. A micromechanical model for multilayered biological materials is proposed to simulate their mechanical deformation and toughening mechanisms. The fundamental hypothesis of the model is the inclusion of nanoscale pillars with near theoretical strength (σth ~ E/30). It is also assumed that pillars and asperities confine the organic matrix to the proximity of the platelets, and, hence, increase their stiffness, since it has been previously shown that the organic matrix behaves more stiffly in the proximity of mineral platelets. The modelling results are in excellent agreement with the available experimental data for abalone nacre. The results demonstrate that the aragonite platelets, pillars and organic matrix synergistically affect the stiffness of nacre, and the pillars significantly contribute to the mechanical performance of nacre. It is also shown that the roughness induced interactions between the organic matrix and aragonite platelet, represented in the model by asperity elements, play a key role in strength and toughness of abalone nacre. The highly nonlinear behaviour of the proposed multilayered material is the result of distributed deformation in the nacre-like structure due to the existence of nano-asperities and nanopillars with near theoretical strength. Finally, tensile toughness is studied as a function of the components in the microstructure of nacre.

Toughening mechanisms in bioinspired multilayered materials

PubMed Central

Askarinejad, Sina; Rahbar, Nima

2015-01-01

Outstanding mechanical properties of biological multilayered materials are strongly influenced by nanoscale features in their structure. In this study, mechanical behaviour and toughening mechanisms of abalone nacre-inspired multilayered materials are explored. In nacre's structure, the organic matrix, pillars and the roughness of the aragonite platelets play important roles in its overall mechanical performance. A micromechanical model for multilayered biological materials is proposed to simulate their mechanical deformation and toughening mechanisms. The fundamental hypothesis of the model is the inclusion of nanoscale pillars with near theoretical strength (σth ~ E/30). It is also assumed that pillars and asperities confine the organic matrix to the proximity of the platelets, and, hence, increase their stiffness, since it has been previously shown that the organic matrix behaves more stiffly in the proximity of mineral platelets. The modelling results are in excellent agreement with the available experimental data for abalone nacre. The results demonstrate that the aragonite platelets, pillars and organic matrix synergistically affect the stiffness of nacre, and the pillars significantly contribute to the mechanical performance of nacre. It is also shown that the roughness induced interactions between the organic matrix and aragonite platelet, represented in the model by asperity elements, play a key role in strength and toughness of abalone nacre. The highly nonlinear behaviour of the proposed multilayered material is the result of distributed deformation in the nacre-like structure due to the existence of nano-asperities and nanopillars with near theoretical strength. Finally, tensile toughness is studied as a function of the components in the microstructure of nacre. PMID:25551150

[Topological models of retention index of thin-layer chromatogram for chiral organic acids].

PubMed

Li, Mingjian; Wang, Yuxiao; Feng, Hui; Feng, Changjun

2014-03-01

On the basis of Kier's molecular connectivity indices and conjugated matrix, novel molecular connectivity indices ((m) G(t)(v)) were defined and calculated for 18 chiral hydroxyl acids and amino acids. The chiral connectivity indices ((m)C(t)(v)) were introduced by extending (m)G(t)(v): (m)C(t)(v) = (m)G(t)(v) x w(j), where w(j) is the chiral index. The quantitative structure-retention index relationship (QSRR) between the retention index (R(M)) of thin-layer chromatogram for the chiral organic acids and (m)C(t)(v) was studied by multivariate statistical regression. By leaps-and-bounds regression analysis, the best four-parameter QSRR model was set up, and the traditional correlation coefficient (R2) and the cross-validation correlation coefficient (Q2) of leave-one-out (LOO) were 0.973 and 0.950, respectively. The results demonstrated that the model was highly reliable and had good predictive ability from the point of view of statistics. From the four parameters (0C(p)(v), 2C(p)(v), C(ch),(v), 5C(p)(v)) of the model, it is known that the dominant influence factors of the retention index were the molecular structure characteristics of two-dimensional and the space factors: the chiral characteristics, the flexibility and the puckered degree of molecules for the chiral organic acids. The results showed that the new parameter mC(t)(v) had good rationality and efficiency for the retention indices of the chiral organic acids. Therefore, an effective method was provided to predict the retention indices of the chiral organic acids.

Evaluating the Relationship between Team Performance and Joint Attention with Longitudinal Multivariate Mixed Models

DTIC Science & Technology

2016-09-23

Lauren Menke3 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER H0HJ (53290813) 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS...as prior work has demonstrated that friendship can facilitate performance in decision-making and motor tasks (e.g., Shah & Jehn, 1993). However, a...Relationship between Team Performance and Joint Attention with Longitudinal Multivariate Mixed Models 5a. CONTRACT NUMBER FA8650-14-D-6501-0009 5b

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dress, W.B.

Rosen's modeling relation is embedded in Popper's three worlds to provide an heuristic tool for model building and a guide for thinking about complex systems. The utility of this construct is demonstrated by suggesting a solution to the problem of pseudo science and a resolution of the famous Bohr-Einstein debates. A theory of bizarre systems is presented by an analogy with entangled particles of quantum mechanics. This theory underscores the poverty of present-day computational systems (e.g., computers) for creating complex and bizarre entities by distinguishing between mechanism and organism.

From clinical integration to accountable care.

PubMed

Shields, Mark

2011-01-01

Four key challenges to reforming health care organizations can be addressed by a clinical integration model patterned after Advocate Physician Partners (APP). These challenges are: predominance of small group practices, dominant fee-for-service reimbursement methods, weaknesses of the traditional hospital medical staff structure and a need to partner with commercial insurance companies. APP has demonstrated teamwork between 3800 physicians and hospitals to improve quality, patient safety and cost-effectiveness. Building on this model, an innovative contract with Blue Cross Blue Shield of Illinois serves as a prototype for a commercial Accountable Care Organization. For this contract to succeed, APP must outperform the market competition. To accomplish this, APP has implemented strategies to reduce readmissions, avoid unnecessary admissions and emergency room visits, expand primary care access, and enhance quality and patient safety.

De novo transcript sequence reconstruction from RNA-Seq: reference generation and analysis with Trinity

PubMed Central

Yassour, Moran; Grabherr, Manfred; Blood, Philip D.; Bowden, Joshua; Couger, Matthew Brian; Eccles, David; Li, Bo; Lieber, Matthias; MacManes, Matthew D.; Ott, Michael; Orvis, Joshua; Pochet, Nathalie; Strozzi, Francesco; Weeks, Nathan; Westerman, Rick; William, Thomas; Dewey, Colin N.; Henschel, Robert; LeDuc, Richard D.; Friedman, Nir; Regev, Aviv

2013-01-01

De novo assembly of RNA-Seq data allows us to study transcriptomes without the need for a genome sequence, such as in non-model organisms of ecological and evolutionary importance, cancer samples, or the microbiome. In this protocol, we describe the use of the Trinity platform for de novo transcriptome assembly from RNA-Seq data in non-model organisms. We also present Trinity’s supported companion utilities for downstream applications, including RSEM for transcript abundance estimation, R/Bioconductor packages for identifying differentially expressed transcripts across samples, and approaches to identify protein coding genes. In an included tutorial we provide a workflow for genome-independent transcriptome analysis leveraging the Trinity platform. The software, documentation and demonstrations are freely available from http://trinityrnaseq.sf.net. PMID:23845962

Mentoring for the New Millennium.

PubMed

Walker, William O; Kelly, Patrick C; Hume, Roderick F

2002-12-01

The challenges and benefits of a formal mentoring program are considered within the context of learning organizations: specifically, graduate medical education and professional development. While no single definition addresses every aspect of mentoring, this process is a distinct one with established traditions and expectations. The core requirements of attraction, action and affect remain and are essential for this adult developmental process to be successful. This paper's review of the literature supports the belief that mentoring has value, even into the next millennium, with some conceptual evolution. We are encouraging a paradigm shift from the traditional dyad model of mentoring to a triad model: organization, mentor, and protégé. The future development of outcome measures will be a necessary goal to demonstrate that both personal and organizational goals can coexist.

Assessing reliability of protein-protein interactions by integrative analysis of data in model organisms.

PubMed

Lin, Xiaotong; Liu, Mei; Chen, Xue-wen

2009-04-29

Protein-protein interactions play vital roles in nearly all cellular processes and are involved in the construction of biological pathways such as metabolic and signal transduction pathways. Although large-scale experiments have enabled the discovery of thousands of previously unknown linkages among proteins in many organisms, the high-throughput interaction data is often associated with high error rates. Since protein interaction networks have been utilized in numerous biological inferences, the inclusive experimental errors inevitably affect the quality of such prediction. Thus, it is essential to assess the quality of the protein interaction data. In this paper, a novel Bayesian network-based integrative framework is proposed to assess the reliability of protein-protein interactions. We develop a cross-species in silico model that assigns likelihood scores to individual protein pairs based on the information entirely extracted from model organisms. Our proposed approach integrates multiple microarray datasets and novel features derived from gene ontology. Furthermore, the confidence scores for cross-species protein mappings are explicitly incorporated into our model. Applying our model to predict protein interactions in the human genome, we are able to achieve 80% in sensitivity and 70% in specificity. Finally, we assess the overall quality of the experimentally determined yeast protein-protein interaction dataset. We observe that the more high-throughput experiments confirming an interaction, the higher the likelihood score, which confirms the effectiveness of our approach. This study demonstrates that model organisms certainly provide important information for protein-protein interaction inference and assessment. The proposed method is able to assess not only the overall quality of an interaction dataset, but also the quality of individual protein-protein interactions. We expect the method to continually improve as more high quality interaction data from more model organisms becomes available and is readily scalable to a genome-wide application.

X-231B technology demonstration for in situ treatment of contaminated soil: Contaminant characterization and three dimensional spatial modeling

DOE Office of Scientific and Technical Information (OSTI.GOV)

West, O.R.; Siegrist, R.L.; Mitchell, T.J.

1993-11-01

Fine-textured soils and sediments contaminated by trichloroethylene (TCE) and other chlorinated organics present a serious environmental restoration challenge at US Department of Energy (DOE) sites. DOE and Martin Marietta Energy Systems, Inc. initiated a research and demonstration project at Oak Ridge National Laboratory. The goal of the project was to demonstrate a process for closure and environmental restoration of the X-231B Solid Waste Management Unit at the DOE Portsmouth Gaseous Diffusion Plant. The X-231B Unit was used from 1976 to 1983 as a land disposal site for waste oils and solvents. Silt and clay deposits beneath the unit were contaminatedmore » with volatile organic compounds and low levels of radioactive substances. The shallow groundwater was also contaminated, and some contaminants were at levels well above drinking water standards. This document begins with a summary of the subsurface physical and contaminant characteristics obtained from investigative studies conducted at the X-231B Unit prior to January 1992 (Sect. 2). This is then followed by a description of the sample collection and analysis methods used during the baseline sampling conducted in January 1992 (Sect. 3). The results of this sampling event were used to develop spatial models for VOC contaminant distribution within the X-231B Unit.« less

Predicting Intentions to Breastfeed for Three Months, Six Months, and One Year Using the Theory of Planned Behavior and Body Satisfaction.

PubMed

Johnson-Young, Elizabeth A

2018-02-27

Breastfeeding is one of the top maternal priorities for many organizations, including the World Health Organization (WHO), The American Academy of Pediatrics (AAP), and the Center for Disease Control (CDC). Focusing on the goals of Healthy People 2020, as well as the recommendations of other organizations, this paper investigates the impacts on women's intentions to breastfeed newborns for 3 months, 6 months, and 1 year. This research used the theory of planned behavior (TPB) as a model to predict intentions for each duration of time. Body satisfaction was included as a moderating variable given research demonstrating a possible connection of body satisfaction to breastfeeding. A survey of 156 pregnant women was conducted. Results demonstrated the importance of the three TPB measures in predicting intentions. Further, significant interactions between body satisfaction and attitudes, as well as body satisfaction and subjective norms were present in predicting intentions to exclusively breastfeed one's baby from infant to 6 months of age. Theoretical implications are discussed, as well as practical implications for breastfeeding interventions and campaigns.

The Dual Role of Disorder on the Dissociation of Interfacial Charge Transfer Excitons

NASA Astrophysics Data System (ADS)

Shi, Liang; Lee, Chee-Kong; Willard, Adam

In organic-based photovoltaics (OPV), dissociation of neutral photo-excitations (i.e., Frenkel excitons) into free charge carriers requires the excitons to overcome binding energy that can significantly exceed thermal energies. The inability of bound charges to overcome this large binding energy has been implicated as a primary source of efficiency loss in OPVs. Despite the potential impact on the performance of organic solar cells much remains to be understood about the microscopic mechanism of exciton dissociation in OPV materials. Here we explore the role of static molecular disorder in mediating this charge dissociation process. Using a simple lattice model of exciton dynamics we demonstrate that random spatial variations in the energetic landscape can mitigate the effects of the exciton binding energy by lowering the free energy barrier. By considering the competition between this thermodynamic effect and the disorder-induced slowing of dissociation kinetics we demonstrate that exciton dissociation yields are expected to depend non-monotonically on the degree of static disorder. We conclude that a certain amount of molecular-scale disorder is desirable in order to optimize the performance of organic photovoltaic materials.

A Unique Procedure to Identify Cell Surface Markers Through a Spherical Self-Organizing Map Applied to DNA Microarray Analysis.

PubMed

Sugii, Yuh; Kasai, Tomonari; Ikeda, Masashi; Vaidyanath, Arun; Kumon, Kazuki; Mizutani, Akifumi; Seno, Akimasa; Tokutaka, Heizo; Kudoh, Takayuki; Seno, Masaharu

2016-01-01

To identify cell-specific markers, we designed a DNA microarray platform with oligonucleotide probes for human membrane-anchored proteins. Human glioma cell lines were analyzed using microarray and compared with normal and fetal brain tissues. For the microarray analysis, we employed a spherical self-organizing map, which is a clustering method suitable for the conversion of multidimensional data into two-dimensional data and displays the relationship on a spherical surface. Based on the gene expression profile, the cell surface characteristics were successfully mirrored onto the spherical surface, thereby distinguishing normal brain tissue from the disease model based on the strength of gene expression. The clustered glioma-specific genes were further analyzed by polymerase chain reaction procedure and immunocytochemical staining of glioma cells. Our platform and the following procedure were successfully demonstrated to categorize the genes coding for cell surface proteins that are specific to glioma cells. Our assessment demonstrates that a spherical self-organizing map is a valuable tool for distinguishing cell surface markers and can be employed in marker discovery studies for the treatment of cancer.

Basigin/CD147 promotes renal fibrosis after unilateral ureteral obstruction.

PubMed

Kato, Noritoshi; Kosugi, Tomoki; Sato, Waichi; Ishimoto, Takuji; Kojima, Hiroshi; Sato, Yuka; Sakamoto, Kazuma; Maruyama, Shoichi; Yuzawa, Yukio; Matsuo, Seiichi; Kadomatsu, Kenji

2011-02-01

Regardless of their primary causes, progressive renal fibrosis and tubular atrophy are the main predictors of progression to end-stage renal disease. Basigin/CD147 is a multifunctional molecule-it induces matrix metalloproteinases and hyaluronan, for example-and has been implicated in organ fibrosis. However, the relationship between basigin and organ fibrosis has been poorly studied. We investigated basigin's role in renal fibrosis using a unilateral ureteral obstruction model. Basigin-deficient mice (Bsg(-/-)) demonstrated significantly less fibrosis after surgery than Bsg(+/+) mice. Fewer macrophages had infiltrated in Bsg(-/-) kidneys. Consistent with these in vivo data, primary cultured tubular epithelial cells from Bsg(-/-) mice produced less matrix metalloproteinase and exhibited less motility on stimulation with transforming growth factor β. Furthermore, Bsg(-/-) embryonic fibro blasts produced less hyaluronan and α-smooth muscle actin after transforming growth factor β stimulation. Together, these results demonstrate for the first time that basigin is a key regulator of renal fibrosis. Basigin could be a candidate target molecule for the prevention of organ fibrosis. Copyright © 2011 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Reflections on experiential learning in evaluation capacity building with a community organization, Dancing With Parkinson's.

PubMed

Nakaima, April; Sridharan, Sanjeev

2017-05-08

This paper discusses what was learned about evaluation capacity building with community organizations who deliver services to individuals with neurological disorders. Evaluation specialists engaged by the Ontario Brain Institute Evaluation Support Program were paired with community organizations, such as Dancing With Parkinson's. Some of the learning included: relationship building is key for this model of capacity building; community organizations often have had negative experiences with evaluation and the idea that evaluations can be friendly tools in implementing meaningful programs is one key mechanism by which such an initiative can work; community organizations often need evaluation most to be able to demonstrate their value; a strength of this initiative was that the focus was not just on creating products but mostly on developing a learning process in which capacities would remain; evaluation tools and skills that organizations found useful were developing a theory of change and the concept of heterogeneous mechanisms (informed by a realist evaluation lens). Copyright © 2017. Published by Elsevier Ltd.

Hygienic quality of artificial greywater subjected to aerobic treatment: a comparison of three filter media at increasing organic loading rates.

PubMed

Lalander, Cecilia; Dalahmeh, Sahar; Jönsson, Håkan; Vinnerås, Björn

2013-01-01

With a growing world population, the lack of reliable water sources is becoming an increasing problem. Reusing greywater could alleviate this problem. When reusing greywater for crop irrigation it is paramount to ensure the removal of pathogenic organisms. This study compared the pathogen removal efficiency of pine bark and activated charcoal filters with that of conventional sand filters at three organic loading rates. The removal efficiency of Escherichia coli O157:H7 decreased drastically when the organic loading rate increased fivefold in the charcoal and sand filters, but increased by 2 log10 in the bark filters. The reduction in the virus model organism coliphage phiX174 remained unchanged with increasing organic loading in the charcoal and sand filters, but increased by 2 log10 in the bark filters. Thus, bark was demonstrated to be the most promising material for greywater treatment in terms of pathogen removal.

Low-order models of a single-screw expander for organic Rankine cycle applications

NASA Astrophysics Data System (ADS)

Ziviani, D.; Desideri, A.; Lemort, V.; De Paepe, M.; van den Broek, M.

2015-08-01

Screw-type volumetric expanders have been demonstrated to be a suitable technology for organic Rankine cycle (ORC) systems because of higher overall effectiveness and good part-load behaviour over other positive displacement machines. An 11 kWe single-screw expander (SSE) adapted from an air compressor has been tested in an ORC test-rig operating with R245fa as working fluid. A total of 60 steady-steady points have been obtained at four different rotational speeds of the expander in the range between 2000 rpm and 3300 rpm. The maximum electrical power output and overall isentropic effectiveness measured were 7.3 kW and 51.9%, respectively. In this paper, a comparison between two low-order models is proposed in terms of accuracy of the predictions, the robustness of the model and the computational time. The first model is the Pacejka equation-based model and the second is a semi-empirical model derived from a well-known scroll expander model and modified to include the geometric aspects of a single screw expander. The models have been calibrated with the available steady-state measurement points by identifying the proper parameters.

Safety climate and culture: Integrating psychological and systems perspectives.

PubMed

Casey, Tristan; Griffin, Mark A; Flatau Harrison, Huw; Neal, Andrew

2017-07-01

Safety climate research has reached a mature stage of development, with a number of meta-analyses demonstrating the link between safety climate and safety outcomes. More recently, there has been interest from systems theorists in integrating the concept of safety culture and to a lesser extent, safety climate into systems-based models of organizational safety. Such models represent a theoretical and practical development of the safety climate concept by positioning climate as part of a dynamic work system in which perceptions of safety act to constrain and shape employee behavior. We propose safety climate and safety culture constitute part of the enabling capitals through which organizations build safety capability. We discuss how organizations can deploy different configurations of enabling capital to exert control over work systems and maintain safe and productive performance. We outline 4 key strategies through which organizations to reconcile the system control problems of promotion versus prevention, and stability versus flexibility. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Divergence in plant and microbial allocation strategies explains continental patterns in microbial allocation and biogeochemical fluxes.

PubMed

Averill, Colin

2014-10-01

Allocation trade-offs shape ecological and biogeochemical phenomena at local to global scale. Plant allocation strategies drive major changes in ecosystem carbon cycling. Microbial allocation to enzymes that decompose carbon vs. organic nutrients may similarly affect ecosystem carbon cycling. Current solutions to this allocation problem prioritise stoichiometric tradeoffs implemented in plant ecology. These solutions may not maximise microbial growth and fitness under all conditions, because organic nutrients are also a significant carbon resource for microbes. I created multiple allocation frameworks and simulated microbial growth using a microbial explicit biogeochemical model. I demonstrate that prioritising stoichiometric trade-offs does not optimise microbial allocation, while exploiting organic nutrients as carbon resources does. Analysis of continental-scale enzyme data supports the allocation patterns predicted by this framework, and modelling suggests large deviations in soil C loss based on which strategy is implemented. Therefore, understanding microbial allocation strategies will likely improve our understanding of carbon cycling and climate. © 2014 John Wiley & Sons Ltd/CNRS.

Deep Residual Network Predicts Cortical Representation and Organization of Visual Features for Rapid Categorization.

PubMed

Wen, Haiguang; Shi, Junxing; Chen, Wei; Liu, Zhongming

2018-02-28

The brain represents visual objects with topographic cortical patterns. To address how distributed visual representations enable object categorization, we established predictive encoding models based on a deep residual network, and trained them to predict cortical responses to natural movies. Using this predictive model, we mapped human cortical representations to 64,000 visual objects from 80 categories with high throughput and accuracy. Such representations covered both the ventral and dorsal pathways, reflected multiple levels of object features, and preserved semantic relationships between categories. In the entire visual cortex, object representations were organized into three clusters of categories: biological objects, non-biological objects, and background scenes. In a finer scale specific to each cluster, object representations revealed sub-clusters for further categorization. Such hierarchical clustering of category representations was mostly contributed by cortical representations of object features from middle to high levels. In summary, this study demonstrates a useful computational strategy to characterize the cortical organization and representations of visual features for rapid categorization.

The role of noise in self-organized decision making by the true slime mold Physarum polycephalum.

PubMed

Meyer, Bernd; Ansorge, Cedrick; Nakagaki, Toshiyuki

2017-01-01

Self-organized mechanisms are frequently encountered in nature and known to achieve flexible, adaptive control and decision-making. Noise plays a crucial role in such systems: It can enable a self-organized system to reliably adapt to short-term changes in the environment while maintaining a generally stable behavior. This is fundamental in biological systems because they must strike a delicate balance between stable and flexible behavior. In the present paper we analyse the role of noise in the decision-making of the true slime mold Physarum polycephalum, an important model species for the investigation of computational abilities in simple organisms. We propose a simple biological experiment to investigate the reaction of P. polycephalum to time-variant risk factors and present a stochastic extension of an established mathematical model for P. polycephalum to analyze this experiment. It predicts that-due to the mechanism of stochastic resonance-noise can enable P. polycephalum to correctly assess time-variant risk factors, while the corresponding noise-free system fails to do so. Beyond the study of P. polycephalum we demonstrate that the influence of noise on self-organized decision-making is not tied to a specific organism. Rather it is a general property of the underlying process dynamics, which appears to be universal across a wide range of systems. Our study thus provides further evidence that stochastic resonance is a fundamental component of the decision-making in self-organized macroscopic and microscopic groups and organisms.

The role of noise in self-organized decision making by the true slime mold Physarum polycephalum

PubMed Central

Ansorge, Cedrick; Nakagaki, Toshiyuki

2017-01-01

Self-organized mechanisms are frequently encountered in nature and known to achieve flexible, adaptive control and decision-making. Noise plays a crucial role in such systems: It can enable a self-organized system to reliably adapt to short-term changes in the environment while maintaining a generally stable behavior. This is fundamental in biological systems because they must strike a delicate balance between stable and flexible behavior. In the present paper we analyse the role of noise in the decision-making of the true slime mold Physarum polycephalum, an important model species for the investigation of computational abilities in simple organisms. We propose a simple biological experiment to investigate the reaction of P. polycephalum to time-variant risk factors and present a stochastic extension of an established mathematical model for P. polycephalum to analyze this experiment. It predicts that—due to the mechanism of stochastic resonance—noise can enable P. polycephalum to correctly assess time-variant risk factors, while the corresponding noise-free system fails to do so. Beyond the study of P. polycephalum we demonstrate that the influence of noise on self-organized decision-making is not tied to a specific organism. Rather it is a general property of the underlying process dynamics, which appears to be universal across a wide range of systems. Our study thus provides further evidence that stochastic resonance is a fundamental component of the decision-making in self-organized macroscopic and microscopic groups and organisms. PMID:28355213

Post-test evaluation of the geology, geochemistry, microbiology, and hydrology of the in situ air stripping demonstration site at the Savannah River Site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eddy Dilek, C.A.; Looney, B.B.; Hazen, T.C.

A full-scale demonstration of the use of horizontal wells for in situ air stripping for environment restoration was completed as part of the Savannah River Integrated Demonstration Program. The demonstration of in situ air stripping was the first in a series of demonstrations of innovative remediation technologies for the cleanup of sites contaminated with volatile organic contaminants. The in situ air stripping system consisted of two directionally drilled wells that delivered gases to and extract contamination from the subsurface. The demonstration was designed to remediate soils and sediments in the unsaturated and saturated zones as well as groundwater contaminated withmore » volatile organic compounds. The demonstration successfully removed significant quantities of solvent from the subsurface. The field site and horizontal wells were subsequently used for an in situ bioremediation demonstration during which methane was added to the injected air. The field conditions documented herein represent the baseline status of the site for evaluating the in situ bioremediation as well as the post-test conditions for the in situ air stripping demonstration. Characterization activities focused on documenting the nature and distribution of contamination in the subsurface. The post-test characterization activities discussed herein include results from the analysis of sediment samples, three-dimensional images of the pretest and post-test data, contaminant inventories estimated from pretest and post-test models, a detailed lithologic cross sections of the site, results of aquifer testing, and measurements of geotechnical parameters of undisturbed core sediments.« less

Synergistic co-digestion of solid-organic-waste and municipal-sewage-sludge: 1 plus 1 equals more than 2 in terms of biogas production and solids reduction.

PubMed

Aichinger, Peter; Wadhawan, Tanush; Kuprian, Martin; Higgins, Matthew; Ebner, Christian; Fimml, Christian; Murthy, Sudhir; Wett, Bernhard

2015-12-15

Making good use of existing water infrastructure by adding organic wastes to anaerobic digesters improves the energy balance of a wastewater treatment plant (WWTP) substantially. This paper explores co-digestion load limits targeting a good trade-off for boosting methane production, and limiting process-drawbacks on nitrogen-return loads, cake-production, solids-viscosity and polymer demand. Bio-methane potential tests using whey as a model co-substrate showed diversification and intensification of the anaerobic digestion process resulting in a synergistical enhancement in sewage sludge methanization. Full-scale case-studies demonstrate organic co-substrate addition of up to 94% of the organic sludge load resulted in tripling of the biogas production. At organic co-substrate addition of up to 25% no significant increase in cake production and only a minor increase in ammonia release of ca. 20% have been observed. Similar impacts were measured at a high-solids digester pilot with up-stream thermal hydrolyses where the organic loading rate was increased by 25% using co-substrate. Dynamic simulations were used to validate the synergistic impact of co-substrate addition on sludge methanization, and an increase in hydrolysis rate from 1.5 d(-1) to 2.5 d(-1) was identified for simulating measured gas production rate. This study demonstrates co-digestion for maximizing synergy as a step towards energy efficiency and ultimately towards carbon neutrality. Copyright © 2015 Elsevier Ltd. All rights reserved.

Fractal-like hierarchical organization of bone begins at the nanoscale

NASA Astrophysics Data System (ADS)

Reznikov, Natalie; Bilton, Matthew; Lari, Leonardo; Stevens, Molly M.; Kröger, Roland

2018-05-01

The components of bone assemble hierarchically to provide stiffness and toughness. However, the organization and relationship between bone’s principal components—mineral and collagen—has not been clearly elucidated. Using three-dimensional electron tomography imaging and high-resolution two-dimensional electron microscopy, we demonstrate that bone mineral is hierarchically assembled beginning at the nanoscale: Needle-shaped mineral units merge laterally to form platelets, and these are further organized into stacks of roughly parallel platelets. These stacks coalesce into aggregates that exceed the lateral dimensions of the collagen fibrils and span adjacent fibrils as continuous, cross-fibrillar mineralization. On the basis of these observations, we present a structural model of hierarchy and continuity for the mineral phase, which contributes to the structural integrity of bone.

The potential of 3D printing in urological research and patient care.

PubMed

Colaco, Marc; Igel, Daniel A; Atala, Anthony

2018-04-01

3D printing is an evolving technology that enables the creation of unique organic and inorganic structures with high precision. In urology, the technology has demonstrated potential uses in both patient and clinician education as well as in clinical practice. The four major techniques used for 3D printing are inkjet printing, extrusion printing, laser sintering, and stereolithography. Each of these techniques can be applied to the production of models for education and surgical planning, prosthetic construction, and tissue bioengineering. Bioengineering is potentially the most important application of 3D printing, as the ability to produce functional organic constructs might, in the future, enable urologists to replicate and replace abnormal tissues with neo-organs, improving patient survival and quality of life.

The internal organization of hospitals: a descriptive study.

PubMed Central

Sloan, F A

1980-01-01

This study presents descriptive information on several dimensions of the internal organization of hospitals, with particular emphasis on medical staff, using data from two unique national surveys. Three alternative theories of hospital behavior by economists are described and evaluated with these data. The study also shows how standard bed size, teaching, and ownership categories relate to important features of hospital organization. In this way, understanding of these standard "control" variables is enhanced. For example, systematic organizational differences between proprietary and other hospitals are reported, holding bed size and teaching status constant. No single theory of hospital behavior emerges as dominant. The tables demonstrate the diversity of hospitals and the likelihood that no single model can adequately describe the behavior of all hospitals. PMID:7204062

Persistence of soil organic matter as an ecosystem property.

PubMed

Schmidt, Michael W I; Torn, Margaret S; Abiven, Samuel; Dittmar, Thorsten; Guggenberger, Georg; Janssens, Ivan A; Kleber, Markus; Kögel-Knabner, Ingrid; Lehmann, Johannes; Manning, David A C; Nannipieri, Paolo; Rasse, Daniel P; Weiner, Steve; Trumbore, Susan E

2011-10-05

Globally, soil organic matter (SOM) contains more than three times as much carbon as either the atmosphere or terrestrial vegetation. Yet it remains largely unknown why some SOM persists for millennia whereas other SOM decomposes readily--and this limits our ability to predict how soils will respond to climate change. Recent analytical and experimental advances have demonstrated that molecular structure alone does not control SOM stability: in fact, environmental and biological controls predominate. Here we propose ways to include this understanding in a new generation of experiments and soil carbon models, thereby improving predictions of the SOM response to global warming.

Persistence of soil organic matter as an ecosystem property

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schmidt, M.W.; Torn, M. S.; Abiven, S.

2011-08-15

Globally, soil organic matter (SOM) contains more than three times as much carbon as either the atmosphere or terrestrial vegetation. Yet it remains largely unknown why some SOM persists for millennia whereas other SOM decomposes readily—and this limits our ability to predict how soils will respond to climate change. Recent analytical and experimental advances have demonstrated that molecular structure alone does not control SOM stability: in fact, environmental and biological controls predominate. Here we propose ways to include this understanding in a new generation of experiments and soil carbon models, thereby improving predictions of the SOM response to global warming.

A Bifunctional Dimethylsulfoxide Substitute Enhances the Aqueous Solubility of Small Organic Molecules

PubMed Central

Sprachman, Melissa M.

2012-01-01

Abstract An oxetane-substituted sulfoxide has demonstrated potential as a dimethylsulfoxide substitute for enhancing the dissolution of organic compounds with poor aqueous solubilities. This sulfoxide may find utility in applications of library storage and biological assays. For the model compounds studied, significant solubility enhancements were observed using the sulfoxide as a cosolvent in aqueous media. Brine shrimp, breast cancer (MDA-MB-231), and liver cell line (HepG2) toxicity data for the new additive are also presented, in addition to comparative IC50 values for a series of PKD1 inhibitors. PMID:22192308

Evaluating the Number of Stages in Development of Squamous Cell and Adenocarcinomas across Cancer Sites Using Human Population-Based Cancer Modeling

PubMed Central

Kravchenko, Julia; Akushevich, Igor; Abernethy, Amy P.; Lyerly, H. Kim

2012-01-01

Background Adenocarcinomas (ACs) and squamous cell carcinomas (SCCs) differ by clinical and molecular characteristics. We evaluated the characteristics of carcinogenesis by modeling the age patterns of incidence rates of ACs and SCCs of various organs to test whether these characteristics differed between cancer subtypes. Methodology/Principal Findings Histotype-specific incidence rates of 14 ACs and 12 SCCs from the SEER Registry (1973–2003) were analyzed by fitting several biologically motivated models to observed age patterns. A frailty model with the Weibull baseline was applied to each age pattern to provide the best fit for the majority of cancers. For each cancer, model parameters describing the underlying mechanisms of carcinogenesis including the number of stages occurring during an individual’s life and leading to cancer (m-stages) were estimated. For sensitivity analysis, the age-period-cohort model was incorporated into the carcinogenesis model to test the stability of the estimates. For the majority of studied cancers, the numbers of m-stages were similar within each group (i.e., AC and SCC). When cancers of the same organs were compared (i.e., lung, esophagus, and cervix uteri), the number of m-stages were more strongly associated with the AC/SCC subtype than with the organ: 9.79±0.09, 9.93±0.19 and 8.80±0.10 for lung, esophagus, and cervical ACs, compared to 11.41±0.10, 12.86±0.34 and 12.01±0.51 for SCCs of the respective organs (p<0.05 between subtypes). Most SCCs had more than ten m-stages while ACs had fewer than ten m-stages. The sensitivity analyses of the model parameters demonstrated the stability of the obtained estimates. Conclusions/Significance A model containing parameters capable of representing the number of stages of cancer development occurring during individual’s life was applied to the large population data on incidence of ACs and SCCs. The model revealed that the number of m-stages differed by cancer subtype being more strongly associated with ACs/SCCs histotype than with organ/site. PMID:22629394

Trivalent Ions under Charged Langmuir Monolayers: Nanoscale Mechanisms for Charge Inversion and Liquid-Liquid Extraction

NASA Astrophysics Data System (ADS)

Miller, Mitchell

Ions dissolved in solution are known to interact in remarkable ways with charged Langmuir monolayers. The organic monolayer can be used as a molecular template for ordered nucleation of inorganic crystals (biomineralization) and functional nanoparticles. However, the clear majority of experiments demonstrating these behaviors have been performed with divalent ions. Trivalent ions are present in several important processes that are unique from previously studied divalent systems. We will demonstrate that trivalent ions under floating monolayers can model two important systems: charge inversion and liquid-liquid solvent extraction. Using in situ synchrotron x-ray scattering and emission methods, we can make direct, nanoscale observations of the interactions between ion and monolayer. Charge inversion is a fascinating phenomenon in which small ions of an opposite charge to some large object (colloidal particle, DNA molecule, etc.) will attach to and reverse the object's charge, rather than simply neutralizing it. There are many experimental systems demonstrating this behavior and an enormous body of theoretical work to explain it. Two classes of explanation exist for how charge inversion may occur, "chemical" and "physical" mechanism. Using grazing incidence diffraction (GID), we have found that ions can form an ordered lattice which is incommensurate to a floating, charged monolayer. Because the ions are incommensurate, they cannot be specifically attached to molecules in the monolayer and must be, therefore, held in place by "physical" means. Solvent extraction can be an extremely complex procedure, so our approach to studying it is to simplify the system into a basic model. Ordinarily, two immiscible liquids--an aqueous phase containing some desired species and other impurities and an organic phase, which sometimes contains extractant molecules that improve efficiency--are mixed together and allowed to separate again. While the liquids are being mixed together, the target species from the aqueous phase is pulled across the interface into the organic phase. The mechanism by which the transfer occurs is very poorly understood and very difficult to study directly since it is a very dynamic process and obscured by the bulk of the liquids. Here we propose that the air-water interface is a model of the liquid-liquid interface; in our model, the hydrophobic "organic" phase is the air above the water. This lets us make direct observations of the interactions between ions dissolved in the aqueous phase and the extractant molecules in the organic phase with x-rays, something which would be impossible in an ordinary solvent extraction experiment. We observed a sharp transition in ordering as the atomic weight of the ion dissolved in solution is increased. One would expect a continuous variation, since the size of the ions varies continuously. Second, using x-ray fluorescence, we find that heavier lanthanides are much more strongly attracted to the monolayer than light ones. The unexpected nature of our results emphasizes the need for bottom-up approaches to understanding these systems rather than the top-down method used for the last century. In addition, our results demonstrate that it is, indeed, possible to overcome the experimental difficulties and make the types of measurements necessary for this approach.

NMOC, ozone, and organic aerosol in the southeastern United States, 1999-2007: 3. Origins of organic aerosol in Atlanta, Georgia, and surrounding areas

NASA Astrophysics Data System (ADS)

Blanchard, C. L.; Hidy, G. M.; Tanenbaum, S.; Edgerton, E. S.

2011-02-01

Carbonaceous compounds constitute a major fraction of the fine particle mass at locations throughout North America; much of the condensed-phase organic carbon (OC) is produced in the atmosphere from NMOC reactions as "secondary" OC (SOC). Ten years of particulate carbon and speciated non-methane organic compound (NMOC) data combined with other measurements from Southeastern Aerosol Research and Characterization (SEARCH) and other sites provide insight into the association between elemental carbon (EC), OC and NMOCs. Data are analyzed to characterize the OC and SOC contrasts between urban Atlanta, Georgia, and nearby non-urban conditions in the Southeast. Analysis of the monitoring record indicates that the mean Atlanta urban excess of total carbon (TC) is 2.1-2.8 μg m -3. The OC/EC ratio of the Atlanta urban excess is in the range 1.3 to 1.8, consistent with OC/EC ratios observed in motor vehicle emissions and a fossil carbon source of urban excess TC. Carbon isotope analysis of a subset of particle samples demonstrates that the urban excess is mainly fossil in origin, even though the majority of the TC is modern at both urban and non-urban sites. Temperature-dependent partitioning of OC between gas and condensed phases cannot explain the observed diurnal and seasonal variations of OC/CO, EC/CO, and OC/EC ratios. Alternatively, a hypothesis involving vertical mixing of OC-enriched air from aloft is supported by the seasonal and diurnal OC, isopentane, aromatic and isoprene observations at the ground. A statistical model is applied to indicate the relative significance of aerometric factors affecting OC and EC concentrations, including meteorological and pollutant associations. The model results demonstrate strong linkages between fine particle carbon and pollutant indicators of source emissions compared with meteorological factors; the model results show weaker dependence of OC on meteorological factors than is the case for ozone (O 3) concentrations.

Emergence of intercolonial variation in termite shelter tube patterns and prediction of its underlying mechanism

PubMed Central

2015-01-01

Building behaviours occur in various organisms from bacteria to humans. Social insects build various structures such as large nests and underground galleries, achieved by self-organization. Structures built by social insects have recently been demonstrated to vary widely in size and shape within a species, even under the same environmental conditions. However, little is known about how intraspecific variation in structures emerges from collective behaviours. Here we show that the colony variation of structures can be generated by simply changing two behavioural parameters of group members, even with the same building algorithm. Our laboratory experiment of termite shelter tube construction demonstrated clear intercolonial variation, and a two-dimensional lattice model showed that it can be attributed to the extent of positive feedback and the number of individuals engaged in building. This study contributes to explaining the great diversity of structures emerging from collective building in social insects. PMID:26715997

An Inherited Efficiencies Model of Non-Genomic Evolution

NASA Technical Reports Server (NTRS)

New, Michael H.; Pohorille, Andrew

1999-01-01

A model for the evolution of biological systems in the absence of a nucleic acid-like genome is proposed and applied to model the earliest living organisms -- protocells composed of membrane encapsulated peptides. Assuming that the peptides can make and break bonds between amino acids, and bonds in non-functional peptides are more likely to be destroyed than in functional peptides, it is demonstrated that the catalytic capabilities of the system as a whole can increase. This increase is defined to be non-genomic evolution. The relationship between the proposed mechanism for evolution and recent experiments on self-replicating peptides is discussed.

OntoCR: A CEN/ISO-13606 clinical repository based on ontologies.

PubMed

Lozano-Rubí, Raimundo; Muñoz Carrero, Adolfo; Serrano Balazote, Pablo; Pastor, Xavier

2016-04-01

To design a new semantically interoperable clinical repository, based on ontologies, conforming to CEN/ISO 13606 standard. The approach followed is to extend OntoCRF, a framework for the development of clinical repositories based on ontologies. The meta-model of OntoCRF has been extended by incorporating an OWL model integrating CEN/ISO 13606, ISO 21090 and SNOMED CT structure. This approach has demonstrated a complete evaluation cycle involving the creation of the meta-model in OWL format, the creation of a simple test application, and the communication of standardized extracts to another organization. Using a CEN/ISO 13606 based system, an indefinite number of archetypes can be merged (and reused) to build new applications. Our approach, based on the use of ontologies, maintains data storage independent of content specification. With this approach, relational technology can be used for storage, maintaining extensibility capabilities. The present work demonstrates that it is possible to build a native CEN/ISO 13606 repository for the storage of clinical data. We have demonstrated semantic interoperability of clinical information using CEN/ISO 13606 extracts. Copyright © 2016 Elsevier Inc. All rights reserved.

Chemical Leasing business models and corporate social responsibility.

PubMed

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.

Radionuclide transfer in marine coastal ecosystems, a modelling study using metabolic processes and site data.

PubMed

Konovalenko, L; Bradshaw, C; Kumblad, L; Kautsky, U

2014-07-01

This study implements new site-specific data and improved process-based transport model for 26 elements (Ac, Ag, Am, Ca, Cl, Cm, Cs, Ho, I, Nb, Ni, Np, Pa, Pb, Pd, Po, Pu, Ra, Se, Sm, Sn, Sr, Tc, Th, U, Zr), and validates model predictions with site measurements and literature data. The model was applied in the safety assessment of a planned nuclear waste repository in Forsmark, Öregrundsgrepen (Baltic Sea). Radionuclide transport models are central in radiological risk assessments to predict radionuclide concentrations in biota and doses to humans. Usually concentration ratios (CRs), the ratio of the measured radionuclide concentration in an organism to the concentration in water, drive such models. However, CRs vary with space and time and CR estimates for many organisms are lacking. In the model used in this study, radionuclides were assumed to follow the circulation of organic matter in the ecosystem and regulated by radionuclide-specific mechanisms and metabolic rates of the organisms. Most input parameters were represented by log-normally distributed probability density functions (PDFs) to account for parameter uncertainty. Generally, modelled CRs for grazers, benthos, zooplankton and fish for the 26 elements were in good agreement with site-specific measurements. The uncertainty was reduced when the model was parameterized with site data, and modelled CRs were most similar to measured values for particle reactive elements and for primary consumers. This study clearly demonstrated that it is necessary to validate models with more than just a few elements (e.g. Cs, Sr) in order to make them robust. The use of PDFs as input parameters, rather than averages or best estimates, enabled the estimation of the probable range of modelled CR values for the organism groups, an improvement over models that only estimate means. Using a mechanistic model that is constrained by ecological processes enables (i) the evaluation of the relative importance of food and water uptake pathways and processes such as assimilation and excretion, (ii) the possibility to extrapolate within element groups (a common requirement in many risk assessments when initial model parameters are scarce) and (iii) predictions of radionuclide uptake in the ecosystem after changes in ecosystem structure or environmental conditions. These features are important for the longterm (>1000 year) risk assessments that need to be considered for a deep nuclear waste repository. Copyright © 2013. Published by Elsevier Ltd.

Registration of organs with sliding interfaces and changing topologies

NASA Astrophysics Data System (ADS)

Berendsen, Floris F.; Kotte, Alexis N. T. J.; Viergever, Max A.; Pluim, Josien P. W.

2014-03-01

Smoothness and continuity assumptions on the deformation field in deformable image registration do not hold for applications where the imaged objects have sliding interfaces. Recent extensions to deformable image registration that accommodate for sliding motion of organs are limited to sliding motion along approximately planar surfaces or cannot model sliding that changes the topological configuration in case of multiple organs. We propose a new extension to free-form image registration that is not limited in this way. Our method uses a transformation model that consists of uniform B-spline transformations for each organ region separately, which is based on segmentation of one image. Since this model can create overlapping regions or gaps between regions, we introduce a penalty term that minimizes this undesired effect. The penalty term acts on the surfaces of the organ regions and is optimized simultaneously with the image similarity. To evaluate our method registrations were performed on publicly available inhale-exhale CT scans for which performances of other methods are known. Target registration errors are computed on dense landmark sets that are available with these datasets. On these data our method outperforms the other methods in terms of target registration error and, where applicable, also in terms of overlap and gap volumes. The approximation of the other methods of sliding motion along planar surfaces is reasonably well suited for the motion present in the lung data. The ability of our method to handle sliding along curved boundaries and for changing region topology configurations was demonstrated on synthetic images.

Ultra-Fine Scale Spatially-Integrated Mapping of Habitat and Occupancy Using Structure-From-Motion.

PubMed

McDowall, Philip; Lynch, Heather J

2017-01-01

Organisms respond to and often simultaneously modify their environment. While these interactions are apparent at the landscape extent, the driving mechanisms often occur at very fine spatial scales. Structure-from-Motion (SfM), a computer vision technique, allows the simultaneous mapping of organisms and fine scale habitat, and will greatly improve our understanding of habitat suitability, ecophysiology, and the bi-directional relationship between geomorphology and habitat use. SfM can be used to create high-resolution (centimeter-scale) three-dimensional (3D) habitat models at low cost. These models can capture the abiotic conditions formed by terrain and simultaneously record the position of individual organisms within that terrain. While coloniality is common in seabird species, we have a poor understanding of the extent to which dense breeding aggregations are driven by fine-scale active aggregation or limited suitable habitat. We demonstrate the use of SfM for fine-scale habitat suitability by reconstructing the locations of nests in a gentoo penguin colony and fitting models that explicitly account for conspecific attraction. The resulting digital elevation models (DEMs) are used as covariates in an inhomogeneous hybrid point process model. We find that gentoo penguin nest site selection is a function of the topography of the landscape, but that nests are far more aggregated than would be expected based on terrain alone, suggesting a strong role of behavioral aggregation in driving coloniality in this species. This integrated mapping of organisms and fine scale habitat will greatly improve our understanding of fine-scale habitat suitability, ecophysiology, and the complex bi-directional relationship between geomorphology and habitat use.

Transfer of radionuclides from high polluted bottom sediments to marine organisms through benthic food chain in post Fukushima period

NASA Astrophysics Data System (ADS)

Bezhenar, Roman; Jung, Kyung Tae; Maderich, Vladimir; Willemsen, Stefan; de With, Govert; Qiao, Fangli

2015-04-01

A catastrophic earthquake and tsunami occurred on March 11, 2011 and severely damaged the Fukushima Daiichi Nuclear Power Plant (FDNPP) that resulted in an uncontrolled release of radioactivity into air and ocean. Around 80% of the radioactivity released due to the FDNPP accident in March-April 2011 was either directly discharged into the ocean or deposited onto the ocean surface from the atmosphere. A large amount of long-lived radionuclides (mainly Cs-137) were released into the environment. The concentration of radionuclides in the ocean reached a maximum in mid-April of 2011, and then gradually decreased. From 2011 the concentration of Cs-137 in water essentially fell except the area around the FDNPP where leaks of contaminated water are continued. However, in the bottom sediment high concentrations of Cs-137 were found in the first months after the accident and slowly decreased with time. Therefore, it should be expected that a time delay is found of sediment-bound radionuclides in marine organisms. For the modeling of radionuclide transfer from highly polluted bottom sediments to marine organisms the dynamical food chain model BURN-POSEIDON (Heling et al, 2002; Maderich et al., 2014) was extended. In this model marine organisms are grouped into a limited number of classes based on their trophic level and type of species. These include: phytoplankton, zooplankton, fishes (two types: piscivorous and non-piscivorous), crustaceans, and molluscs for pelagic food chain and bottom sediment invertebrates, demersal fishes and bottom predators for benthic food chain and whole water column predators feeding by pelagial and benthic fishes. Bottom invertebrates consume organic parts of bottom sediments with adsorbed radionuclides which then migrate through the food chain. All organisms take radionuclides directly from water as well as via food. In fishes where radioactivity is not homogeneously distributed over all tissues of the organism, it is assumed that radionuclide accumulates in a specific tissue called target tissue. This tissue (bone, flesh, stomach, and organs) controls the overall elimination rate of the nuclide in the organism. The model prediction for the coastal area around the FDNPP agree well with observations. In addition the effects from the Chernobyl accident on the Baltic Sea are modelled and these results also are in good agreement with available data. These results demonstrate the importance of the benthic food chain in long-term transfer of radionuclides from high polluted bottom sediments to the marine organisms. The developed model can be applied for different regions of the World Ocean.

Alchemical and structural distribution based representation for universal quantum machine learning

NASA Astrophysics Data System (ADS)

Faber, Felix A.; Christensen, Anders S.; Huang, Bing; von Lilienfeld, O. Anatole

2018-06-01

We introduce a representation of any atom in any chemical environment for the automatized generation of universal kernel ridge regression-based quantum machine learning (QML) models of electronic properties, trained throughout chemical compound space. The representation is based on Gaussian distribution functions, scaled by power laws and explicitly accounting for structural as well as elemental degrees of freedom. The elemental components help us to lower the QML model's learning curve, and, through interpolation across the periodic table, even enable "alchemical extrapolation" to covalent bonding between elements not part of training. This point is demonstrated for the prediction of covalent binding in single, double, and triple bonds among main-group elements as well as for atomization energies in organic molecules. We present numerical evidence that resulting QML energy models, after training on a few thousand random training instances, reach chemical accuracy for out-of-sample compounds. Compound datasets studied include thousands of structurally and compositionally diverse organic molecules, non-covalently bonded protein side-chains, (H2O)40-clusters, and crystalline solids. Learning curves for QML models also indicate competitive predictive power for various other electronic ground state properties of organic molecules, calculated with hybrid density functional theory, including polarizability, heat-capacity, HOMO-LUMO eigenvalues and gap, zero point vibrational energy, dipole moment, and highest vibrational fundamental frequency.

Diverse data supports the transition of filamentous fungal model organisms into the post-genomics era

DOE PAGES

McCluskey, Kevin; Baker, Scott E.

2017-02-17

As model organisms filamentous fungi have been important since the beginning of modern biological inquiry and have benefitted from open data since the earliest genetic maps were shared. From early origins in simple Mendelian genetics of mating types, parasexual genetics of colony colour, and the foundational demonstration of the segregation of a nutritional requirement, the contribution of research systems utilising filamentous fungi has spanned the biochemical genetics era, through the molecular genetics era, and now are at the very foundation of diverse omics approaches to research and development. Fungal model organisms have come from most major taxonomic groups although Ascomycetemore » filamentous fungi have seen the most major sustained effort. In addition to the published material about filamentous fungi, shared molecular tools have found application in every area of fungal biology. Likewise, shared data has contributed to the success of model systems. Furthermore, the scale of data supporting research with filamentous fungi has grown by 10 to 12 orders of magnitude. From genetic to molecular maps, expression databases, and finally genome resources, the open and collaborative nature of the research communities has assured that the rising tide of data has lifted all of the research systems together.« less

Diverse data supports the transition of filamentous fungal model organisms into the post-genomics era

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCluskey, Kevin; Baker, Scott E.

As model organisms filamentous fungi have been important since the beginning of modern biological inquiry and have benefitted from open data since the earliest genetic maps were shared. From early origins in simple Mendelian genetics of mating types, parasexual genetics of colony colour, and the foundational demonstration of the segregation of a nutritional requirement, the contribution of research systems utilising filamentous fungi has spanned the biochemical genetics era, through the molecular genetics era, and now are at the very foundation of diverse omics approaches to research and development. Fungal model organisms have come from most major taxonomic groups although Ascomycetemore » filamentous fungi have seen the most major sustained effort. In addition to the published material about filamentous fungi, shared molecular tools have found application in every area of fungal biology. Likewise, shared data has contributed to the success of model systems. Furthermore, the scale of data supporting research with filamentous fungi has grown by 10 to 12 orders of magnitude. From genetic to molecular maps, expression databases, and finally genome resources, the open and collaborative nature of the research communities has assured that the rising tide of data has lifted all of the research systems together.« less

Loops determine the mechanical properties of mitotic chromosomes

NASA Astrophysics Data System (ADS)

Zhang, Yang; Heermann, Dieter W.

2013-03-01

In mitosis, chromosomes undergo a condensation into highly compacted, rod-like objects. Many models have been put forward for the higher-order organization of mitotic chromosomes including radial loop and hierarchical folding models. Additionally, mechanical properties of mitotic chromosomes under different conditions were measured. However, the internal organization of mitotic chromosomes still remains unclear. Here we present a polymer model for mitotic chromosomes and show how chromatin loops play a major role for their mechanical properties. The key assumption of the model is the ability of the chromatin fibre to dynamically form loops with the help of binding proteins. Our results show that looping leads to a tight compaction and significantly increases the bending rigidity of chromosomes. Moreover, our qualitative prediction of the force elongation behaviour is close to experimental findings. This indicates that the internal structure of mitotic chromosomes is based on self-organization of the chromatin fibre. We also demonstrate how number and size of loops have a strong influence on the mechanical properties. We suggest that changes in the mechanical characteristics of chromosomes can be explained by an altered internal loop structure. YZ gratefully appreciates funding by the German National Academic Foundation (Studienstiftung des deutschen Volkes) and support by the Heidelberg Graduate School for Mathematical and Computational Methods in the Sciences (HGS MathComp).

Final Technical Report for Award SC0008613

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knopf, Daniel A.

Discovering how aerosol particles, present in the atmosphere in sizes of a few nanometers to hundred micrometers, initiate ice crystal formation represents a great challenge. Atmospheric ice nucleation is important because ice crystals alter the radiative properties of clouds and thus climate, and impact precipitation and thus the hydrological cycle. The difficulty in predicting atmospheric ice formation is attributable at least in part, to the diversity of ice nucleation pathways, the physical and chemical complexity of the ice nucleating particles (INPs), and the relatively small numbers of INPs (compared with all other aerosol particles), sometimes less than one in 100000.more » These factors in turn makes constraining ice nucleation parameterizations for modeling applications challenging. The majority of airborne particles are known to be organic in nature or contain organic biogenic material. The presence of organic material adds to the complexity of the particles and therefore the predictability of ice nucleation events since the organic species can display different phase states, e.g. liquid or solid, in response to temperature and humidity. The award DE-SC0008613 to PI Prof. Daniel Knopf at Stony Brook University, “Relating the Chemical and Physical Properties of Aerosols to the Water Uptake and Ice Nucleation Potential of Particles Collected During the Carbonaceous Aerosols and Radiative Effects Study (CARES)”, allowed examination of laboratory generated aerosol particles and field-collected particles for their propensity to nucleate ice under typical tropospheric conditions and relate ice nucleation to the physicochemical properties of the particles including their morphology and chemical composition. This in turn allowed for development of ice nucleation parameterizations for implementation in cloud models. The award resulted in 10 peer-reviewed publications and more than 20 seminar and conference presentations. We demonstrated that the rate of immersion freezing, when a particle immersed in an aqueous droplet acts as an ice nucleus (IN), can be predicted by knowledge of the IN particle type present and the droplet’s water activity which is equal to ambient relative humidity. Our water activity based immersion freezing model is successful in predicting freezing data including INPs such as mineral dusts, marine biological material, organic species, and surfactant molecules. Its mathematical simplicity makes it an ideal candidate for implementation in cloud and climate models. Furthermore, we could show that this model can reproduce many past laboratory measurements which were generated using a variety of instruments to study immersion freezing. Lastly, we have demonstrated that this model can also be applied to field collected particles. Currently, this novel physical parameterization of immersion freezing is being implemented in a cloud model. We examined the physicochemical properties and the ice nucleation potential of particles collected during CARES applying a novel experimental method that allows identification of the individual INPs within a large population of particles sampled from an ambient environment. Taking advantage of a variety of micro-spectroscopic techniques, we characterized the composition and morphology of IN and non-IN particles present in the airborne population. We developed a new parameterization for quantifying the mixing state of the entire aerosol populations by introducing a mixing state index. We found that the identified INPs belong to the most common particle-type classes observed in the CARES field samples and as such are not special or rare particles. In other words, the INPs can be shown not to be unique in contrast to the common paradigm of being rare and exceptional. Either there are differences between particles acting as IN and particles not acting as IN which are beyond our current detection limit or nucleation occurs randomly on the surface of any one of these compositionally equivalent particles. These results suggest that total particle surface area of the different particle types present in the aerosol population is also a crucial factor when predicting ice nucleation in an air mass. We also observed that ambient organic aerosol particles can initiate ice nucleation and corroborated these findings using laboratory generated organic particles. These experiments demonstrated that information of the organic phase state is important for predicting the ice nucleation pathway and the ability of an organic particle to participate in atmospheric ice crystal formation. This award resulted in substantial new insights in the processes governing immersion freezing, the role of organic aerosol particles in ice cloud formation, and the importance of the ambient aerosol population for prediction of ice nucleation in an air parcel. These findings have significant implications for modeling and field measurement strategies of atmospheric ice nucleation.« less

Modelling the multidimensional niche by linking functional traits to competitive performance

PubMed Central

Maynard, Daniel S.; Leonard, Kenneth E.; Drake, John M.; Hall, David W.; Crowther, Thomas W.; Bradford, Mark A.

2015-01-01

Linking competitive outcomes to environmental conditions is necessary for understanding species' distributions and responses to environmental change. Despite this importance, generalizable approaches for predicting competitive outcomes across abiotic gradients are lacking, driven largely by the highly complex and context-dependent nature of biotic interactions. Here, we present and empirically test a novel niche model that uses functional traits to model the niche space of organisms and predict competitive outcomes of co-occurring populations across multiple resource gradients. The model makes no assumptions about the underlying mode of competition and instead applies to those settings where relative competitive ability across environments correlates with a quantifiable performance metric. To test the model, a series of controlled microcosm experiments were conducted using genetically related strains of a widespread microbe. The model identified trait microevolution and performance differences among strains, with the predicted competitive ability of each organism mapped across a two-dimensional carbon and nitrogen resource space. Areas of coexistence and competitive dominance between strains were identified, and the predicted competitive outcomes were validated in approximately 95% of the pairings. By linking trait variation to competitive ability, our work demonstrates a generalizable approach for predicting and modelling competitive outcomes across changing environmental contexts. PMID:26136444

An "age"-structured model of hematopoietic stem cell organization with application to chronic myeloid leukemia.

PubMed

Roeder, Ingo; Herberg, Maria; Horn, Matthias

2009-04-01

Previously, we have modeled hematopoietic stem cell organization by a stochastic, single cell-based approach. Applications to different experimental systems demonstrated that this model consistently explains a broad variety of in vivo and in vitro data. A major advantage of the agent-based model (ABM) is the representation of heterogeneity within the hematopoietic stem cell population. However, this advantage comes at the price of time-consuming simulations if the systems become large. One example in this respect is the modeling of disease and treatment dynamics in patients with chronic myeloid leukemia (CML), where the realistic number of individual cells to be considered exceeds 10(6). To overcome this deficiency, without losing the representation of the inherent heterogeneity of the stem cell population, we here propose to approximate the ABM by a system of partial differential equations (PDEs). The major benefit of such an approach is its independence from the size of the system. Although this mean field approach includes a number of simplifying assumptions compared to the ABM, it retains the key structure of the model including the "age"-structure of stem cells. We show that the PDE model qualitatively and quantitatively reproduces the results of the agent-based approach.

Utilizing ARC EMCS Seedling Cassettes as Highly Versatile Miniature Growth Chambers for Model Organism Experiments

NASA Technical Reports Server (NTRS)

Freeman, John L.; Steele, Marianne K.; Sun, Gwo-Shing; Heathcote, David; Reinsch, S.; DeSimone, Julia C.; Myers, Zachary A.

2014-01-01

The aim of our ground testing was to demonstrate the capability of safely putting specific model organisms into dehydrated stasis, and to later rehydrate and successfully grow them inside flight proven ARC EMCS seedling cassettes. The ARC EMCS seedling cassettes were originally developed to support seedling growth during space flight. The seeds are attached to a solid substrate, launched dry, and then rehydrated in a small volume of media on orbit to initiate the experiment. We hypothesized that the same seedling cassettes should be capable of acting as culture chambers for a wide range of organisms with minimal or no modification. The ability to safely preserve live organisms in a dehydrated state allows for on orbit experiments to be conducted at the best time for crew operations and more importantly provides a tightly controlled physiologically relevant growth experiment with specific environmental parameters. Thus, we performed a series of ground tests that involved growing the organisms, preparing them for dehydration on gridded Polyether Sulfone (PES) membranes, dry storage at ambient temperatures for varying periods of time, followed by rehydration. Inside the culture cassettes, the PES membranes were mounted above blotters containing dehydrated growth media. These were mounted on stainless steel bases and sealed with plastic covers that have permeable membrane covered ports for gas exchange. The results showed we were able to demonstrate acceptable normal growth of C.elegans (nematodes), E.coli (bacteria), S.cerevisiae (yeast), Polytrichum (moss) spores and protonemata, C.thalictroides (fern), D.discoideum (amoeba), and H.dujardini (tardigrades). All organisms showed acceptable growth and rehydration in both petri dishes and culture cassettes initially, and after various time lengths of dehydration. At the end of on orbit ISS European Modular Cultivation System experiments the cassettes could be frozen at ultra-low temperatures, refrigerated, or chemically preserved before being returned to Earth for analyses. Our results suggest that with protocol modifications and future verification testing we can utilize the versatile EMCS to conduct tightly controlled experiments inside our culture cassettes for a wide variety of organisms. These physiological experiments would be designed to answer questions at the molecular level about the specific stress responses of space flight.

Handwashing and Ebola virus disease outbreaks: A randomized comparison of soap, hand sanitizer, and 0.05% chlorine solutions on the inactivation and removal of model organisms Phi6 and E. coli from hands and persistence in rinse water.

PubMed

Wolfe, Marlene K; Gallandat, Karin; Daniels, Kyle; Desmarais, Anne Marie; Scheinman, Pamela; Lantagne, Daniele

2017-01-01

To prevent Ebola transmission, frequent handwashing is recommended in Ebola Treatment Units and communities. However, little is known about which handwashing protocol is most efficacious. We evaluated six handwashing protocols (soap and water, alcohol-based hand sanitizer (ABHS), and 0.05% sodium dichloroisocyanurate, high-test hypochlorite, and stabilized and non-stabilized sodium hypochlorite solutions) for 1) efficacy of handwashing on the removal and inactivation of non-pathogenic model organisms and, 2) persistence of organisms in rinse water. Model organisms E. coli and bacteriophage Phi6 were used to evaluate handwashing with and without organic load added to simulate bodily fluids. Hands were inoculated with test organisms, washed, and rinsed using a glove juice method to retrieve remaining organisms. Impact was estimated by comparing the log reduction in organisms after handwashing to the log reduction without handwashing. Rinse water was collected to test for persistence of organisms. Handwashing resulted in a 1.94-3.01 log reduction in E. coli concentration without, and 2.18-3.34 with, soil load; and a 2.44-3.06 log reduction in Phi6 without, and 2.71-3.69 with, soil load. HTH performed most consistently well, with significantly greater log reductions than other handwashing protocols in three models. However, the magnitude of handwashing efficacy differences was small, suggesting protocols are similarly efficacious. Rinse water demonstrated a 0.28-4.77 log reduction in remaining E. coli without, and 0.21-4.49 with, soil load and a 1.26-2.02 log reduction in Phi6 without, and 1.30-2.20 with, soil load. Chlorine resulted in significantly less persistence of E. coli in both conditions and Phi6 without soil load in rinse water (p<0.001). Thus, chlorine-based methods may offer a benefit of reducing persistence in rinse water. We recommend responders use the most practical handwashing method to ensure hand hygiene in Ebola contexts, considering the potential benefit of chlorine-based methods in rinse water persistence.

Group-level self-definition and self-investment: a hierarchical (multicomponent) model of in-group identification.

PubMed

Leach, Colin Wayne; van Zomeren, Martijn; Zebel, Sven; Vliek, Michael L W; Pennekamp, Sjoerd F; Doosje, Bertjan; Ouwerkerk, Jaap W; Spears, Russell

2008-07-01

Recent research shows individuals' identification with in-groups to be psychologically important and socially consequential. However, there is little agreement about how identification should be conceptualized or measured. On the basis of previous work, the authors identified 5 specific components of in-group identification and offered a hierarchical 2-dimensional model within which these components are organized. Studies 1 and 2 used confirmatory factor analysis to validate the proposed model of self-definition (individual self-stereotyping, in-group homogeneity) and self-investment (solidarity, satisfaction, and centrality) dimensions, across 3 different group identities. Studies 3 and 4 demonstrated the construct validity of the 5 components by examining their (concurrent) correlations with established measures of in-group identification. Studies 5-7 demonstrated the predictive and discriminant validity of the 5 components by examining their (prospective) prediction of individuals' orientation to, and emotions about, real intergroup relations. Together, these studies illustrate the conceptual and empirical value of a hierarchical multicomponent model of in-group identification.

Using LiDAR and remote microclimate loggers to downscale near-surface air temperatures for site-level studies

Treesearch

Andrew D. George; Frank R. Thompson; John. Faaborg

2015-01-01

A spatial mismatch exists between regional climate models and conditions experienced by individual organisms. We demonstrate an approach to downscaling air temperatures for site-level studies using airborne LiDAR data and remote microclimate loggers. In 2012-2013, we established a temperature logger network in the forested region of central Missouri, USA, and obtained...

A probabilistic model of debris-flow delivery to stream channels, demonstrated for the Coast Range of Oregon, USA

Treesearch

Daniel J. Miller; Kelly M. Burnett

2008-01-01

Debris flows are important geomorphic agents in mountainous terrains that shape channel environments and add a dynamic element to sediment supply and channel disturbance. Identification of channels susceptible to debris-flow inputs of sediment and organic debris, and quantification of the likelihood and magnitude of those inputs, are key tasks for characterizing...

Demonstration of Advanced EMI Models for Live-Site UXO Discrimination at Former Camp Butner, North Carolina

DTIC Science & Technology

2012-05-01

GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7 . PERFORMING ORGANIZATION NAME(S...2.3.3 Classification using template matching ...................................................... 7 2.4 Details of classification schemes... 7 2.4.1 Camp Butner TEMTADS data inversion and classification scheme .......... 9

Advances in small animal mesentery models for in vivo flow cytometry, dynamic microscopy, and drug screening

PubMed Central

Galanzha, Ekaterina I; Tuchin, Valery V; Zharov, Vladimir P

2007-01-01

Using animal mesentery with intravital optical microscopy is a well-established experimental model for studying blood and lymph microcirculation in vivo. Recent advances in cell biology and optical techniques provide the basis for extending this model for new applications, which should generate significantly improved experimental data. This review summarizes the achievements in this specific area, including in vivo label-free blood and lymph photothermal flow cytometry, super-sensitive fluorescence image cytometry, light scattering and speckle flow cytometry, microvessel dynamic microscopy, infrared (IR) angiography, and high-speed imaging of individual cells in fast flow. The capabilities of these techniques, using the rat mesentery model, were demonstrated in various studies; e.g., real-time quantitative detection of circulating and migrating individual blood and cancer cells, studies on vascular dynamics with a focus on lymphatics under normal conditions and under different interventions (e.g. lasers, drugs, nicotine), assessment of lymphatic disturbances from experimental lymphedema, monitoring cell traffic between blood and lymph systems, and high-speed imaging of cell transient deformability in flow. In particular, the obtained results demonstrated that individual cell transportation in living organisms depends on cell type (e.g., normal blood or leukemic cells), the cell’s functional state (e.g., live, apoptotic, or necrotic), and the functional status of the organism. Possible future applications, including in vivo early diagnosis and prevention of disease, monitoring immune response and apoptosis, chemo- and radio-sensitivity tests, and drug screening, are also discussed. PMID:17226898

The macroevolutionary consequences of phenotypic integration: from development to deep time.

PubMed

Goswami, A; Smaers, J B; Soligo, C; Polly, P D

2014-08-19

Phenotypic integration is a pervasive characteristic of organisms. Numerous analyses have demonstrated that patterns of phenotypic integration are conserved across large clades, but that significant variation also exists. For example, heterochronic shifts related to different mammalian reproductive strategies are reflected in postcranial skeletal integration and in coordination of bone ossification. Phenotypic integration and modularity have been hypothesized to shape morphological evolution, and we extended simulations to confirm that trait integration can influence both the trajectory and magnitude of response to selection. We further demonstrate that phenotypic integration can produce both more and less disparate organisms than would be expected under random walk models by repartitioning variance in preferred directions. This effect can also be expected to favour homoplasy and convergent evolution. New empirical analyses of the carnivoran cranium show that rates of evolution, in contrast, are not strongly influenced by phenotypic integration and show little relationship to morphological disparity, suggesting that phenotypic integration may shape the direction of evolutionary change, but not necessarily the speed of it. Nonetheless, phenotypic integration is problematic for morphological clocks and should be incorporated more widely into models that seek to accurately reconstruct both trait and organismal evolution.

Stability and Responsiveness in a Self-Organized Living Architecture

PubMed Central

Garnier, Simon; Murphy, Tucker; Lutz, Matthew; Hurme, Edward; Leblanc, Simon; Couzin, Iain D.

2013-01-01

Robustness and adaptability are central to the functioning of biological systems, from gene networks to animal societies. Yet the mechanisms by which living organisms achieve both stability to perturbations and sensitivity to input are poorly understood. Here, we present an integrated study of a living architecture in which army ants interconnect their bodies to span gaps. We demonstrate that these self-assembled bridges are a highly effective means of maintaining traffic flow over unpredictable terrain. The individual-level rules responsible depend only on locally-estimated traffic intensity and the number of neighbours to which ants are attached within the structure. We employ a parameterized computational model to reveal that bridges are tuned to be maximally stable in the face of regular, periodic fluctuations in traffic. However analysis of the model also suggests that interactions among ants give rise to feedback processes that result in bridges being highly responsive to sudden interruptions in traffic. Subsequent field experiments confirm this prediction and thus the dual nature of stability and flexibility in living bridges. Our study demonstrates the importance of robust and adaptive modular architecture to efficient traffic organisation and reveals general principles regarding the regulation of form in biological self-assemblies. PMID:23555219

Ciona intestinalis as a Marine Model System to Study Some Key Developmental Genes Targeted by the Diatom-Derived Aldehyde Decadienal

PubMed Central

Lettieri, Anna; Esposito, Rosaria; Ianora, Adrianna; Spagnuolo, Antonietta

2015-01-01

The anti-proliferative effects of diatoms, described for the first time in copepods, have also been demonstrated in benthic invertebrates such as polychaetes, sea urchins and tunicates. In these organisms PUAs (polyunsaturated aldehydes) induce the disruption of gametogenesis, gamete functionality, fertilization, embryonic mitosis, and larval fitness and competence. These inhibitory effects are due to the PUAs, produced by diatoms in response to physical damage as occurs during copepod grazing. The cell targets of these compounds remain largely unknown. Here we identify some of the genes targeted by the diatom PUA 2-trans-4-trans-decadienal (DD) using the tunicate Ciona intestinalis. The tools, techniques and genomic resources available for Ciona, as well as the suitability of Ciona embryos for medium-to high-throughput strategies, are key to their employment as model organisms in different fields, including the investigation of toxic agents that could interfere with developmental processes. We demonstrate that DD can induce developmental aberrations in Ciona larvae in a dose-dependent manner. Moreover, through a preliminary analysis, DD is shown to affect the expression level of genes involved in stress response and developmental processes. PMID:25789602

The macroevolutionary consequences of phenotypic integration: from development to deep time

PubMed Central

Goswami, A.; Smaers, J. B.; Soligo, C.; Polly, P. D.

2014-01-01

Phenotypic integration is a pervasive characteristic of organisms. Numerous analyses have demonstrated that patterns of phenotypic integration are conserved across large clades, but that significant variation also exists. For example, heterochronic shifts related to different mammalian reproductive strategies are reflected in postcranial skeletal integration and in coordination of bone ossification. Phenotypic integration and modularity have been hypothesized to shape morphological evolution, and we extended simulations to confirm that trait integration can influence both the trajectory and magnitude of response to selection. We further demonstrate that phenotypic integration can produce both more and less disparate organisms than would be expected under random walk models by repartitioning variance in preferred directions. This effect can also be expected to favour homoplasy and convergent evolution. New empirical analyses of the carnivoran cranium show that rates of evolution, in contrast, are not strongly influenced by phenotypic integration and show little relationship to morphological disparity, suggesting that phenotypic integration may shape the direction of evolutionary change, but not necessarily the speed of it. Nonetheless, phenotypic integration is problematic for morphological clocks and should be incorporated more widely into models that seek to accurately reconstruct both trait and organismal evolution. PMID:25002699

Control of complex networks requires both structure and dynamics

NASA Astrophysics Data System (ADS)

Gates, Alexander J.; Rocha, Luis M.

2016-04-01

The study of network structure has uncovered signatures of the organization of complex systems. However, there is also a need to understand how to control them; for example, identifying strategies to revert a diseased cell to a healthy state, or a mature cell to a pluripotent state. Two recent methodologies suggest that the controllability of complex systems can be predicted solely from the graph of interactions between variables, without considering their dynamics: structural controllability and minimum dominating sets. We demonstrate that such structure-only methods fail to characterize controllability when dynamics are introduced. We study Boolean network ensembles of network motifs as well as three models of biochemical regulation: the segment polarity network in Drosophila melanogaster, the cell cycle of budding yeast Saccharomyces cerevisiae, and the floral organ arrangement in Arabidopsis thaliana. We demonstrate that structure-only methods both undershoot and overshoot the number and which sets of critical variables best control the dynamics of these models, highlighting the importance of the actual system dynamics in determining control. Our analysis further shows that the logic of automata transition functions, namely how canalizing they are, plays an important role in the extent to which structure predicts dynamics.

Influence of ovarian muscle contraction and oocyte growth on egg chamber elongation in Drosophila.

PubMed

Andersen, Darcy; Horne-Badovinac, Sally

2016-04-15

Organs are formed from multiple cell types that make distinct contributions to their shape. The Drosophila egg chamber provides a tractable model to dissect such contributions during morphogenesis. Egg chambers consist of 16 germ cells (GCs) surrounded by a somatic epithelium. Initially spherical, these structures elongate as they mature. This morphogenesis is thought to occur through a 'molecular corset' mechanism, whereby structural elements within the epithelium become circumferentially organized perpendicular to the elongation axis and resist the expansive growth of the GCs to promote elongation. Whether this epithelial organization provides the hypothesized constraining force has been difficult to discern, however, and a role for GC growth has not been demonstrated. Here, we provide evidence for this mechanism by altering the contractile activity of the tubular muscle sheath that surrounds developing egg chambers. Muscle hypo-contraction indirectly reduces GC growth and shortens the egg, which demonstrates the necessity of GC growth for elongation. Conversely, muscle hyper-contraction enhances the elongation program. Although this is an abnormal function for this muscle, this observation suggests that a corset-like force from the egg chamber's exterior could promote its lengthening. These findings highlight how physical contributions from several cell types are integrated to shape an organ. © 2016. Published by The Company of Biologists Ltd.

Influence of ovarian muscle contraction and oocyte growth on egg chamber elongation in Drosophila

PubMed Central

Andersen, Darcy; Horne-Badovinac, Sally

2016-01-01

Organs are formed from multiple cell types that make distinct contributions to their shape. The Drosophila egg chamber provides a tractable model to dissect such contributions during morphogenesis. Egg chambers consist of 16 germ cells (GCs) surrounded by a somatic epithelium. Initially spherical, these structures elongate as they mature. This morphogenesis is thought to occur through a ‘molecular corset’ mechanism, whereby structural elements within the epithelium become circumferentially organized perpendicular to the elongation axis and resist the expansive growth of the GCs to promote elongation. Whether this epithelial organization provides the hypothesized constraining force has been difficult to discern, however, and a role for GC growth has not been demonstrated. Here, we provide evidence for this mechanism by altering the contractile activity of the tubular muscle sheath that surrounds developing egg chambers. Muscle hypo-contraction indirectly reduces GC growth and shortens the egg, which demonstrates the necessity of GC growth for elongation. Conversely, muscle hyper-contraction enhances the elongation program. Although this is an abnormal function for this muscle, this observation suggests that a corset-like force from the egg chamber's exterior could promote its lengthening. These findings highlight how physical contributions from several cell types are integrated to shape an organ. PMID:26952985

Particle size-dependent organ distribution of gold nanoparticles after intravenous administration.

PubMed

De Jong, Wim H; Hagens, Werner I; Krystek, Petra; Burger, Marina C; Sips, Adriënne J A M; Geertsma, Robert E

2008-04-01

A kinetic study was performed to determine the influence of particle size on the in vivo tissue distribution of spherical-shaped gold nanoparticles in the rat. Gold nanoparticles were chosen as model substances as they are used in several medical applications. In addition, the detection of the presence of gold is feasible with no background levels in the body in the normal situation. Rats were intravenously injected in the tail vein with gold nanoparticles with a diameter of 10, 50, 100 and 250 nm, respectively. After 24 h, the rats were sacrificed and blood and various organs were collected for gold determination. The presence of gold was measured quantitatively with inductively coupled plasma mass spectrometry (ICP-MS). For all gold nanoparticle sizes the majority of the gold was demonstrated to be present in liver and spleen. A clear difference was observed between the distribution of the 10 nm particles and the larger particles. The 10 nm particles were present in various organ systems including blood, liver, spleen, kidney, testis, thymus, heart, lung and brain, whereas the larger particles were only detected in blood, liver and spleen. The results demonstrate that tissue distribution of gold nanoparticles is size-dependent with the smallest 10nm nanoparticles showing the most widespread organ distribution.

Exploring Patterns of Soil Organic Matter Decomposition with Students through the Global Decomposition Project (GDP) and the Interactive Model of Leaf Decomposition (IMOLD)

NASA Astrophysics Data System (ADS)

Steiner, S. M.; Wood, J. H.

2015-12-01

As decomposition rates are affected by climate change, understanding crucial soil interactions that affect plant growth and decomposition becomes a vital part of contributing to the students' knowledge base. The Global Decomposition Project (GDP) is designed to introduce and educate students about soil organic matter and decomposition through a standardized protocol for collecting, reporting, and sharing data. The Interactive Model of Leaf Decomposition (IMOLD) utilizes animations and modeling to learn about the carbon cycle, leaf anatomy, and the role of microbes in decomposition. Paired together, IMOLD teaches the background information and allows simulation of numerous scenarios, and the GDP is a data collection protocol that allows students to gather usable measurements of decomposition in the field. Our presentation will detail how the GDP protocol works, how to obtain or make the materials needed, and how results will be shared. We will also highlight learning objectives from the three animations of IMOLD, and demonstrate how students can experiment with different climates and litter types using the interactive model to explore a variety of decomposition scenarios. The GDP demonstrates how scientific methods can be extended to educate broader audiences, and data collected by students can provide new insight into global patterns of soil decomposition. Using IMOLD, students will gain a better understanding of carbon cycling in the context of litter decomposition, as well as learn to pose questions they can answer with an authentic computer model. Using the GDP protocols and IMOLD provide a pathway for scientists and educators to interact and reach meaningful education and research goals.

Heterotopic expression of class B floral homeotic genes supports a modified ABC model for tulip (Tulipa gesneriana).

PubMed

Kanno, Akira; Saeki, Hiroshi; Kameya, Toshiaki; Saedler, Heinz; Theissen, Günter

2003-07-01

In higher eudicotyledonous angiosperms the floral organs are typically arranged in four different whorls, containing sepals, petals, stamens and carpels. According to the ABC model, the identity of these organs is specified by floral homeotic genes of class A, A+B, B+C and C, respectively. In contrast to the sepal and petal whorls of eudicots, the perianths of many plants from the Liliaceae family have two outer whorls of almost identical petaloid organs, called tepals. To explain the Liliaceae flower morphology, van Tunen et al. (1993) proposed a modified ABC model, exemplified with tulip. According to this model, class B genes are not only expressed in whorls 2 and 3, but also in whorl 1. Thus the organs of both whorls 1 and 2 express class A plus class B genes and, therefore, get the same petaloid identity. To test this modified ABC model we have cloned and characterized putative class B genes from tulip. Two DEF- and one GLO-like gene were identified, named TGDEFA, TGDEFB and TGGLO. Northern hybridization analysis showed that all of these genes are expressed in whorls 1, 2 and 3 (outer and inner tepals and stamens), thus corroborating the modified ABC model. In addition, these experiments demonstrated that TGGLO is also weakly expressed in carpels, leaves, stems and bracts. Gel retardation assays revealed that TGGLO alone binds to DNA as a homodimer. In contrast, TGDEFA and TGDEFB cannot homodimerize, but make heterodimers with PI. Homodimerization of GLO-like protein has also been reported for lily, suggesting that this phenomenon is conserved within Liliaceae plants or even monocot species.

Grammomys surdaster, the Natural Host for Plasmodium berghei Parasites, as a Model to Study Whole-Organism Vaccines Against Malaria.

PubMed

Conteh, Solomon; Anderson, Charles; Lambert, Lynn; Orr-Gonzalez, Sachy; Herrod, Jessica; Robbins, Yvette L; Carter, Dariyen; Karhemere, Stomy Bin Shamamba; Pyana, Pati; Büscher, Philippe; Duffy, Patrick E

2017-04-01

AbstractInbred mice are commonly used to test candidate malaria vaccines, but have been unreliable for predicting efficacy in humans. To establish a more rigorous animal model, we acquired African woodland thicket rats of the genus Grammomys , the natural hosts for Plasmodium berghei . Thicket rats were acquired and identified as Grammomys surdaster by skull and teeth measurements and mitochondrial DNA genotyping. Herein, we demonstrate that thicket rats are highly susceptible to infection by P. berghei , and moderately susceptible to Plasmodium yoelii and Plasmodium chabaudi : 1-2 infected mosquito bites or 25-100 sporozoites administered by intravenous injection consistently resulted in patent parasitemia with P. berghei , and resulted in patent parasitemia with P. yoelii and P. chabaudi strains for at least 50% of animals. We then assessed efficacy of whole-organism vaccines to induce sterile immunity, and compared the thicket rat model to conventional mouse models. Using P. berghei ANKA radiation-attenuated sporozoites, and P. berghei ANKA and P. yoelii chemoprophylaxis vaccination approaches, we found that standard doses of vaccine sufficient to protect laboratory mice for a long duration against malaria challenge, are insufficient to protect thicket rats, which require higher doses of vaccine to achieve even short-term sterile immunity. Thicket rats may offer a more stringent and pertinent model for evaluating whole-organism vaccines.

A Non-catalytic Deep Desulphurization Process using Hydrodynamic Cavitation

PubMed Central

Suryawanshi, Nalinee B.; Bhandari, Vinay M.; Sorokhaibam, Laxmi Gayatri; Ranade, Vivek V.

2016-01-01

A novel approach is developed for desulphurization of fuels or organics without use of catalyst. In this process, organic and aqueous phases are mixed in a predefined manner under ambient conditions and passed through a cavitating device. Vapor cavities formed in the cavitating device are then collapsed which generate (in-situ) oxidizing species which react with the sulphur moiety resulting in the removal of sulphur from the organic phase. In this work, vortex diode was used as a cavitating device. Three organic solvents (n-octane, toluene and n-octanol) containing known amount of a model sulphur compound (thiophene) up to initial concentrations of 500 ppm were used to verify the proposed method. A very high removal of sulphur content to the extent of 100% was demonstrated. The nature of organic phase and the ratio of aqueous to organic phase were found to be the most important process parameters. The results were also verified and substantiated using commercial diesel as a solvent. The developed process has great potential for deep of various organics, in general, and for transportation fuels, in particular. PMID:27605492

A Non-catalytic Deep Desulphurization Process using Hydrodynamic Cavitation.

PubMed

Suryawanshi, Nalinee B; Bhandari, Vinay M; Sorokhaibam, Laxmi Gayatri; Ranade, Vivek V

2016-09-08

A novel approach is developed for desulphurization of fuels or organics without use of catalyst. In this process, organic and aqueous phases are mixed in a predefined manner under ambient conditions and passed through a cavitating device. Vapor cavities formed in the cavitating device are then collapsed which generate (in-situ) oxidizing species which react with the sulphur moiety resulting in the removal of sulphur from the organic phase. In this work, vortex diode was used as a cavitating device. Three organic solvents (n-octane, toluene and n-octanol) containing known amount of a model sulphur compound (thiophene) up to initial concentrations of 500 ppm were used to verify the proposed method. A very high removal of sulphur content to the extent of 100% was demonstrated. The nature of organic phase and the ratio of aqueous to organic phase were found to be the most important process parameters. The results were also verified and substantiated using commercial diesel as a solvent. The developed process has great potential for deep of various organics, in general, and for transportation fuels, in particular.

Many facets of reluctance: African Americans and the decision (not) to donate organs.

PubMed Central

Morgan, Susan E.

2006-01-01

Although the body of research on African Americans and organ donation continues to grow, the literature still suffers from a lack of reliance on theory to guide research as well as a surfeit of advanced statistical analytical strategies. A more sophisticated approach to understanding the barriers and facilitating factors that African Americans experience in the process of making the decision to become potential organ donors would yield more sound campaign strategies to increase donation. In this study, a sample of 310 African-American adult members of the NAACP was surveyed about their attitudes, knowledge and beliefs about organ donation. Logistic regression demonstrated that the level of knowledge, attitudes, social norms and altruism resulted in correct classification of organ donor card status in 69.3% of cases. When variables such as medical mistrust, bodily integrity and religiosity were added, an even more powerful model resulted, with 73.2% of the cases correctly classified according to organ donor card status. Recommendations for campaigns targeting African Americans' willingness to donate organs are offered. PMID:16749644

A Non-catalytic Deep Desulphurization Process using Hydrodynamic Cavitation

NASA Astrophysics Data System (ADS)

Suryawanshi, Nalinee B.; Bhandari, Vinay M.; Sorokhaibam, Laxmi Gayatri; Ranade, Vivek V.

2016-09-01

A novel approach is developed for desulphurization of fuels or organics without use of catalyst. In this process, organic and aqueous phases are mixed in a predefined manner under ambient conditions and passed through a cavitating device. Vapor cavities formed in the cavitating device are then collapsed which generate (in-situ) oxidizing species which react with the sulphur moiety resulting in the removal of sulphur from the organic phase. In this work, vortex diode was used as a cavitating device. Three organic solvents (n-octane, toluene and n-octanol) containing known amount of a model sulphur compound (thiophene) up to initial concentrations of 500 ppm were used to verify the proposed method. A very high removal of sulphur content to the extent of 100% was demonstrated. The nature of organic phase and the ratio of aqueous to organic phase were found to be the most important process parameters. The results were also verified and substantiated using commercial diesel as a solvent. The developed process has great potential for deep of various organics, in general, and for transportation fuels, in particular.

Adaptation of video game UVW mapping to 3D visualization of gene expression patterns

NASA Astrophysics Data System (ADS)

Vize, Peter D.; Gerth, Victor E.

2007-01-01

Analysis of gene expression patterns within an organism plays a critical role in associating genes with biological processes in both health and disease. During embryonic development the analysis and comparison of different gene expression patterns allows biologists to identify candidate genes that may regulate the formation of normal tissues and organs and to search for genes associated with congenital diseases. No two individual embryos, or organs, are exactly the same shape or size so comparing spatial gene expression in one embryo to that in another is difficult. We will present our efforts in comparing gene expression data collected using both volumetric and projection approaches. Volumetric data is highly accurate but difficult to process and compare. Projection methods use UV mapping to align texture maps to standardized spatial frameworks. This approach is less accurate but is very rapid and requires very little processing. We have built a database of over 180 3D models depicting gene expression patterns mapped onto the surface of spline based embryo models. Gene expression data in different models can easily be compared to determine common regions of activity. Visualization software, both Java and OpenGL optimized for viewing 3D gene expression data will also be demonstrated.

Production of organic compounds in plasmas: A comparison among electric sparks, laser-induced plasmas and UV light

NASA Technical Reports Server (NTRS)

Scattergood, T. W.; Mckay, C. P.; Borucki, W. J.; Giver, L. P.; Vanghyseghem, H.; Parris, J. E.; Miller, S. L.

1991-01-01

In order to study the production of organic compounds in plasmas (and shocks), various mixtures of N2, CH4, and H2, modeling the atmosphere of Titan, were exposed to discrete sparks, laser-induced plasmas (LIP) and ultraviolet light. The yields of HCN and simple hydrocarbons were measured and compared to those calculated from a simple quenched thermodynamic equilibrium model. The agreement between experiment and theory was fair for HCN and C2H2. However, the yields of C2H6 and other hydrocarbons were much higher than those predicted by the model. Our experiments suggest that photolysis by ultraviolet light from the plasma is an important process in the synthesis. This was confirmed by the photolysis of gas samples exposed to the light, but not to the plasma or shock waves. The results of these experiments demonstrate that, in addition to the well-known efficient synthesis of organic compounds in plasmas, the yields of saturated species, e.g., ethane, may be higher than predicted by theory and that LIP provide a convenient and clean way of simulating planetary lightning and impact plasmas in the laboratory.

Quantity of dates trumps quality of dates for dense Bayesian radiocarbon sediment chronologies - Gas ion source 14C dating instructed by simultaneous Bayesian accumulation rate modeling

NASA Astrophysics Data System (ADS)

Rosenheim, B. E.; Firesinger, D.; Roberts, M. L.; Burton, J. R.; Khan, N.; Moyer, R. P.

2016-12-01

Radiocarbon (14C) sediment core chronologies benefit from a high density of dates, even when precision of individual dates is sacrificed. This is demonstrated by a combined approach of rapid 14C analysis of CO2 gas generated from carbonates and organic material coupled with Bayesian statistical modeling. Analysis of 14C is facilitated by the gas ion source on the Continuous Flow Accelerator Mass Spectrometry (CFAMS) system at the Woods Hole Oceanographic Institution's National Ocean Sciences Accelerator Mass Spectrometry facility. This instrument is capable of producing a 14C determination of +/- 100 14C y precision every 4-5 minutes, with limited sample handling (dissolution of carbonates and/or combustion of organic carbon in evacuated containers). Rapid analysis allows over-preparation of samples to include replicates at each depth and/or comparison of different sample types at particular depths in a sediment or peat core. Analysis priority is given to depths that have the least chronologic precision as determined by Bayesian modeling of the chronology of calibrated ages. Use of such a statistical approach to determine the order in which samples are run ensures that the chronology constantly improves so long as material is available for the analysis of chronologic weak points. Ultimately, accuracy of the chronology is determined by the material that is actually being dated, and our combined approach allows testing of different constituents of the organic carbon pool and the carbonate minerals within a core. We will present preliminary results from a deep-sea sediment core abundant in deep-sea foraminifera as well as coastal wetland peat cores to demonstrate statistical improvements in sediment- and peat-core chronologies obtained by increasing the quantity and decreasing the quality of individual dates.

Widespread Non-Hematopoietic Tissue Distribution by Transplanted Human Progenitor Cells with High Aldehyde Dehydrogenase Activity

PubMed Central

Hess, David A.; Craft, Timothy P.; Wirthlin, Louisa; Hohm, Sarah; Zhou, Ping; Eades, William C.; Creer, Michael H.; Sands, Mark S.; Nolta, Jan A.

2011-01-01

Transplanted adult progenitor cells distribute to peripheral organs and can promote endogenous cellular repair in damaged tissues. However, development of cell-based regenerative therapies has been hindered by the lack of pre-clinical models to efficiently assess multiple organ distribution and difficulty defining human cells with regenerative function. After transplantation into beta-glucuronidase (GUSB)-deficient NOD/SCID/MPSVII mice, we characterized the distribution of lineage depleted human umbilical cord blood-derived cells purified by selection using high aldehyde dehydrogenase activity (ALDH) with CD133 co-expression. ALDHhi or ALDHhiCD133+ cells produced robust hematopoietic reconstitution, and variable levels of tissue distribution in multiple organs. GUSB+ donor cells that co-expressed human (HLA-A,B,C) and hematopoietic (CD45+) cell surface markers were the primary cell phenotype found adjacent to the vascular beds of several tissues, including islet and ductal regions of mouse pancreata. In contrast, variable phenotypes were detected in the chimeric liver, with HLA+/CD45+ cells demonstrating robust GUSB expression adjacent to blood vessels, and CD45−/HLA− cells with diluted GUSB expression predominant in the liver parenchyma. However, true non-hematopoietic human (HLA+/CD45−) cells were rarely detected in other peripheral tissues, suggesting that these GUSB+/HLA−/CD45− cells in the liver were a result of downregulated human surface marker expression in vivo, not widespread seeding of non-hematopoietic cells. However, relying solely on continued expression of cell surface markers, as employed in traditional xenotransplantation models, may underestimate true tissue distribution. ALDH-expressing progenitor cells demonstrated widespread and tissue-specific distribution of variable cellular phenotypes, indicating that these adult progenitor cells should be explored in transplantation models of tissue damage. PMID:18055447

1994 conceptual model of the carbon tetrachloride contamination in the 200 West Area at the Hanford Site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rohay, V.J.

1994-08-01

Between 1955 and 1973, a total of 363,000 to 580,000 L (577,000 to kg) of liquid carbon tetrachloride, in mixtures with other organic and aqueous, actinide-bearing fluids, were discharged to the soil column at three disposal facilities -- the 216-Z-9 Trench, the 216-Z-lA TiTe Field, and the 216-Z-18 Crib -- in the 200 West Area at the Hanford Site. In the mid-1980`s, dissolved carbon tetrachloride was found in the uppermost aquifer beneath the disposal facilities, and in late 1990, the US Environmental Protection Agency and the Washington State Department of Ecology requested that the US Department of Energy proceed withmore » planning and implementation of an expedited response action (ERA) to minimize additional carbon tetrachloride contamination of the groundwater. In February 1992, soil vapor extraction was initiated to remove carbon tetrachloride from the unsaturated zone beneath these disposal facilities. By May 1994, a total of 10,560 L (16,790 kg) of carbon tetrachloride had been removed, amounting to an estimated 2% of the discharged inventory. In the spring of 1991, the Volatile Organic Compounds -- Arid Integrated Demonstration (VOC-Arid ID) program selected the carbon tetrachloride-contaminated site for demonstration and deployment of new technologies for evaluation and cleanup of volatile organic compounds and associated contaminants in soils and groundwater at arid sites. Site investigations conducted in support of both the ERA and the VOC-Arid ID have been integrated because of their shared objective to refine the conceptual model of the site and to promote efficiency. Site characterization data collected in fiscal year 1993 have supported and led to refinement of the conceptual model of the carbon tetrachloride site.« less

Multidisciplinary Design Optimization for Aeropropulsion Engines and Solid Modeling/Animation via the Integrated Forced Methods

NASA Technical Reports Server (NTRS)

2004-01-01

The grant closure report is organized in the following four chapters: Chapter describes the two research areas Design optimization and Solid mechanics. Ten journal publications are listed in the second chapter. Five highlights is the subject matter of chapter three. CHAPTER 1. The Design Optimization Test Bed CometBoards. CHAPTER 2. Solid Mechanics: Integrated Force Method of Analysis. CHAPTER 3. Five Highlights: Neural Network and Regression Methods Demonstrated in the Design Optimization of a Subsonic Aircraft. Neural Network and Regression Soft Model Extended for PX-300 Aircraft Engine. Engine with Regression and Neural Network Approximators Designed. Cascade Optimization Strategy with Neural network and Regression Approximations Demonstrated on a Preliminary Aircraft Engine Design. Neural Network and Regression Approximations Used in Aircraft Design.

A material sensitivity study on the accuracy of deformable organ registration using linear biomechanical models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chi, Y.; Liang, J.; Yan, D.

2006-02-15

Model-based deformable organ registration techniques using the finite element method (FEM) have recently been investigated intensively and applied to image-guided adaptive radiotherapy (IGART). These techniques assume that human organs are linearly elastic material, and their mechanical properties are predetermined. Unfortunately, the accurate measurement of the tissue material properties is challenging and the properties usually vary between patients. A common issue is therefore the achievable accuracy of the calculation due to the limited access to tissue elastic material constants. In this study, we performed a systematic investigation on this subject based on tissue biomechanics and computer simulations to establish the relationshipsmore » between achievable registration accuracy and tissue mechanical and organ geometrical properties. Primarily we focused on image registration for three organs: rectal wall, bladder wall, and prostate. The tissue anisotropy due to orientation preference in tissue fiber alignment is captured by using an orthotropic or a transversely isotropic elastic model. First we developed biomechanical models for the rectal wall, bladder wall, and prostate using simplified geometries and investigated the effect of varying material parameters on the resulting organ deformation. Then computer models based on patient image data were constructed, and image registrations were performed. The sensitivity of registration errors was studied by perturbating the tissue material properties from their mean values while fixing the boundary conditions. The simulation results demonstrated that registration error for a subvolume increases as its distance from the boundary increases. Also, a variable associated with material stability was found to be a dominant factor in registration accuracy in the context of material uncertainty. For hollow thin organs such as rectal walls and bladder walls, the registration errors are limited. Given 30% in material uncertainty, the registration error is limited to within 1.3 mm. For a solid organ such as the prostate, the registration errors are much larger. Given 30% in material uncertainty, the registration error can reach 4.5 mm. However, the registration error distribution for prostates shows that most of the subvolumes have a much smaller registration error. A deformable organ registration technique that uses FEM is a good candidate in IGART if the mean material parameters are available.« less