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Sample records for 3-dimensional medical model

  1. The Effectiveness of an Interactive 3-Dimensional Computer Graphics Model for Medical Education

    PubMed Central

    Konishi, Takeshi; Tamura, Yoko; Moriguchi, Hiroki

    2012-01-01

    Background Medical students often have difficulty achieving a conceptual understanding of 3-dimensional (3D) anatomy, such as bone alignment, muscles, and complex movements, from 2-dimensional (2D) images. To this end, animated and interactive 3-dimensional computer graphics (3DCG) can provide better visual information to users. In medical fields, research on the advantages of 3DCG in medical education is relatively new. Objective To determine the educational effectiveness of interactive 3DCG. Methods We divided 100 participants (27 men, mean (SD) age 17.9 (0.6) years, and 73 women, mean (SD) age 18.1 (1.1) years) from the Health Sciences University of Mongolia (HSUM) into 3DCG (n = 50) and textbook-only (control) (n = 50) groups. The control group used a textbook and 2D images, while the 3DCG group was trained to use the interactive 3DCG shoulder model in addition to a textbook. We conducted a questionnaire survey via an encrypted satellite network between HSUM and Tokushima University. The questionnaire was scored on a 5-point Likert scale from strongly disagree (score 1) to strongly agree (score 5). Results Interactive 3DCG was effective in undergraduate medical education. Specifically, there was a significant difference in mean (SD) scores between the 3DCG and control groups in their response to questionnaire items regarding content (4.26 (0.69) vs 3.85 (0.68), P = .001) and teaching methods (4.33 (0.65) vs 3.74 (0.79), P < .001), but no significant difference in the Web category. Participants also provided meaningful comments on the advantages of interactive 3DCG. Conclusions Interactive 3DCG materials have positive effects on medical education when properly integrated into conventional education. In particular, our results suggest that interactive 3DCG is more efficient than textbooks alone in medical education and can motivate students to understand complex anatomical structures. PMID:23611759

  2. 3-Dimensional Topographic Models for the Classroom

    NASA Technical Reports Server (NTRS)

    Keller, J. W.; Roark, J. H.; Sakimoto, S. E. H.; Stockman, S.; Frey, H. V.

    2003-01-01

    We have recently undertaken a program to develop educational tools using 3-dimensional solid models of digital elevation data acquired by the Mars Orbital Laser Altimeter (MOLA) for Mars as well as a variety of sources for elevation data of the Earth. This work is made possible by the use of rapid prototyping technology to construct solid 3-Dimensional models of science data. We recently acquired rapid prototyping machine that builds 3-dimensional models in extruded plastic. While the machine was acquired to assist in the design and development of scientific instruments and hardware, it is also fully capable of producing models of spacecraft remote sensing data. We have demonstrated this by using Mars Orbiter Laser Altimeter (MOLA) topographic data and Earth based topographic data to produce extruded plastic topographic models which are visually appealing and instantly engage those who handle them.

  3. Incorporating 3-dimensional models in online articles

    PubMed Central

    Cevidanes, Lucia H. S.; Ruellasa, Antonio C. O.; Jomier, Julien; Nguyen, Tung; Pieper, Steve; Budin, Francois; Styner, Martin; Paniagua, Beatriz

    2015-01-01

    Introduction The aims of this article were to introduce the capability to view and interact with 3-dimensional (3D) surface models in online publications, and to describe how to prepare surface models for such online 3D visualizations. Methods Three-dimensional image analysis methods include image acquisition, construction of surface models, registration in a common coordinate system, visualization of overlays, and quantification of changes. Cone-beam computed tomography scans were acquired as volumetric images that can be visualized as 3D projected images or used to construct polygonal meshes or surfaces of specific anatomic structures of interest. The anatomic structures of interest in the scans can be labeled with color (3D volumetric label maps), and then the scans are registered in a common coordinate system using a target region as the reference. The registered 3D volumetric label maps can be saved in .obj, .ply, .stl, or .vtk file formats and used for overlays, quantification of differences in each of the 3 planes of space, or color-coded graphic displays of 3D surface distances. Results All registered 3D surface models in this study were saved in .vtk file format and loaded in the Elsevier 3D viewer. In this study, we describe possible ways to visualize the surface models constructed from cone-beam computed tomography images using 2D and 3D figures. The 3D surface models are available in the article’s online version for viewing and downloading using the reader’s software of choice. These 3D graphic displays are represented in the print version as 2D snapshots. Overlays and color-coded distance maps can be displayed using the reader’s software of choice, allowing graphic assessment of the location and direction of changes or morphologic differences relative to the structure of reference. The interpretation of 3D overlays and quantitative color-coded maps requires basic knowledge of 3D image analysis. Conclusions When submitting manuscripts, authors can

  4. Development and Validation of a 3-Dimensional CFB Furnace Model

    NASA Astrophysics Data System (ADS)

    Vepsäläinen, Arl; Myöhänen, Karl; Hyppäneni, Timo; Leino, Timo; Tourunen, Antti

    At Foster Wheeler, a three-dimensional CFB furnace model is essential part of knowledge development of CFB furnace process regarding solid mixing, combustion, emission formation and heat transfer. Results of laboratory and pilot scale phenomenon research are utilized in development of sub-models. Analyses of field-test results in industrial-scale CFB boilers including furnace profile measurements are simultaneously carried out with development of 3-dimensional process modeling, which provides a chain of knowledge that is utilized as feedback for phenomenon research. Knowledge gathered by model validation studies and up-to-date parameter databases are utilized in performance prediction and design development of CFB boiler furnaces. This paper reports recent development steps related to modeling of combustion and formation of char and volatiles of various fuel types in CFB conditions. Also a new model for predicting the formation of nitrogen oxides is presented. Validation of mixing and combustion parameters for solids and gases are based on test balances at several large-scale CFB boilers combusting coal, peat and bio-fuels. Field-tests including lateral and vertical furnace profile measurements and characterization of solid materials provides a window for characterization of fuel specific mixing and combustion behavior in CFB furnace at different loads and operation conditions. Measured horizontal gas profiles are projection of balance between fuel mixing and reactions at lower part of furnace and are used together with both lateral temperature profiles at bed and upper parts of furnace for determination of solid mixing and combustion model parameters. Modeling of char and volatile based formation of NO profiles is followed by analysis of oxidizing and reducing regions formed due lower furnace design and mixing characteristics of fuel and combustion airs effecting to formation ofNO furnace profile by reduction and volatile-nitrogen reactions. This paper presents

  5. Manufacturing models of fetal malformations built from 3-dimensional ultrasound, magnetic resonance imaging, and computed tomography scan data.

    PubMed

    Werner, Heron; Rolo, Liliam Cristine; Araujo Júnior, Edward; Dos Santos, Jorge Roberto Lopes

    2014-03-01

    Technological innovations accompanying advances in medicine have given rise to the possibility of obtaining better-defined fetal images that assist in medical diagnosis and contribute toward genetic counseling offered to parents during the prenatal period. In this article, we show our innovative experience of diagnosing fetal malformations through correlating 3-dimensional ultrasonography, magnetic resonance imaging, and computed tomography, which are accurate techniques for fetal assessment, with a fetal image reconstruction technique to create physical fetal models. PMID:24901782

  6. 3-dimensional orthodontics visualization system with dental study models and orthopantomograms

    NASA Astrophysics Data System (ADS)

    Zhang, Hua; Ong, S. H.; Foong, K. W. C.; Dhar, T.

    2005-04-01

    The aim of this study is to develop a system that provides 3-dimensional visualization of orthodontic treatments. Dental plaster models and corresponding orthopantomogram (dental panoramic tomogram) are first digitized and fed into the system. A semi-auto segmentation technique is applied to the plaster models to detect the dental arches, tooth interstices and gum margins, which are used to extract individual crown models. 3-dimensional representation of roots, generated by deforming generic tooth models with orthopantomogram using radial basis functions, is attached to corresponding crowns to enable visualization of complete teeth. An optional algorithm to close the gaps between deformed roots and actual crowns by using multi-quadratic radial basis functions is also presented, which is capable of generating smooth mesh representation of complete 3-dimensional teeth. User interface is carefully designed to achieve a flexible system with as much user friendliness as possible. Manual calibration and correction is possible throughout the data processing steps to compensate occasional misbehaviors of automatic procedures. By allowing the users to move and re-arrange individual teeth (with their roots) on a full dentition, this orthodontic visualization system provides an easy and accurate way of simulation and planning of orthodontic treatment. Its capability of presenting 3-dimensional root information with only study models and orthopantomogram is especially useful for patients who do not undergo CT scanning, which is not a routine procedure in most orthodontic cases.

  7. Creating 3-dimensional Models of the Photosphere using the SIR Code

    NASA Astrophysics Data System (ADS)

    Thonhofer, S.; Utz, D.; Jurčák, J.; Pauritsch, J.; Hanslmeier, A.; Lemmerer, B.

    A high-resolution 3-dimensional model of the photospheric magnetic field is essential for the investigation of magnetic features such as sunspots, pores or smaller elements like single flux tubes seen as magnetic bright points. The SIR code is an advanced inversion code that retrieves physical quantities, e.g. magnetic field, from Stokes profiles. Based on this code, we developed a program for automated inversion of Hinode SOT/SP data and for storing these results in 3-dimensional data cubes in the form of fits files. We obtained models of the temperature, magnetic field strength, magnetic field angles and LOS-velocity in a region of the quiet sun. We will give a first discussion of those parameters in regards of small scale magnetic fields and what we can obtain and learn in the future.

  8. A Novel Medical Image Protection Scheme Using a 3-Dimensional Chaotic System

    PubMed Central

    Fu, Chong; Zhang, Gao-yuan; Bian, Ou; Lei, Wei-min; Ma, Hong-feng

    2014-01-01

    Recently, great concerns have been raised regarding the issue of medical image protection due to the increasing demand for telemedicine services, especially the teleradiology service. To meet this challenge, a novel chaos-based approach is suggested in this paper. To address the security and efficiency problems encountered by many existing permutation-diffusion type image ciphers, the new scheme utilizes a single 3D chaotic system, Chen's chaotic system, for both permutation and diffusion. In the permutation stage, we introduce a novel shuffling mechanism, which shuffles each pixel in the plain image by swapping it with another pixel chosen by two of the three state variables of Chen's chaotic system. The remaining variable is used for quantification of pseudorandom keystream for diffusion. Moreover, the selection of state variables is controlled by plain pixel, which enhances the security against known/chosen-plaintext attack. Thorough experimental tests are carried out and the results indicate that the proposed scheme provides an effective and efficient way for real-time secure medical image transmission over public networks. PMID:25541941

  9. Experimental Validation of Plastic Mandible Models Produced by a "Low-Cost" 3-Dimensional Fused Deposition Modeling Printer.

    PubMed

    Maschio, Federico; Pandya, Mirali; Olszewski, Raphael

    2016-01-01

    BACKGROUND The objective of this study was to investigate the accuracy of 3-dimensional (3D) plastic (ABS) models generated using a low-cost 3D fused deposition modelling printer. MATERIAL AND METHODS Two human dry mandibles were scanned with a cone beam computed tomography (CBCT) Accuitomo device. Preprocessing consisted of 3D reconstruction with Maxilim software and STL file repair with Netfabb software. Then, the data were used to print 2 plastic replicas with a low-cost 3D fused deposition modeling printer (Up plus 2®). Two independent observers performed the identification of 26 anatomic landmarks on the 4 mandibles (2 dry and 2 replicas) with a 3D measuring arm. Each observer repeated the identifications 20 times. The comparison between the dry and plastic mandibles was based on 13 distances: 8 distances less than 12 mm and 5 distances greater than 12 mm. RESULTS The mean absolute difference (MAD) was 0.37 mm, and the mean dimensional error (MDE) was 3.76%. The MDE decreased to 0.93% for distances greater than 12 mm CONCLUSIONS Plastic models generated using the low-cost 3D printer UPplus2® provide dimensional accuracies comparable to other well-established rapid prototyping technologies. Validated low-cost 3D printers could represent a step toward the better accessibility of rapid prototyping technologies in the medical field. PMID:27003456

  10. Experimental Validation of Plastic Mandible Models Produced by a “Low-Cost” 3-Dimensional Fused Deposition Modeling Printer

    PubMed Central

    Maschio, Federico; Pandya, Mirali; Olszewski, Raphael

    2016-01-01

    Background The objective of this study was to investigate the accuracy of 3-dimensional (3D) plastic (ABS) models generated using a low-cost 3D fused deposition modelling printer. Material/Methods Two human dry mandibles were scanned with a cone beam computed tomography (CBCT) Accuitomo device. Preprocessing consisted of 3D reconstruction with Maxilim software and STL file repair with Netfabb software. Then, the data were used to print 2 plastic replicas with a low-cost 3D fused deposition modeling printer (Up plus 2®). Two independent observers performed the identification of 26 anatomic landmarks on the 4 mandibles (2 dry and 2 replicas) with a 3D measuring arm. Each observer repeated the identifications 20 times. The comparison between the dry and plastic mandibles was based on 13 distances: 8 distances less than 12 mm and 5 distances greater than 12 mm. Results The mean absolute difference (MAD) was 0.37 mm, and the mean dimensional error (MDE) was 3.76%. The MDE decreased to 0.93% for distances greater than 12 mm. Conclusions Plastic models generated using the low-cost 3D printer UPplus2® provide dimensional accuracies comparable to other well-established rapid prototyping technologies. Validated low-cost 3D printers could represent a step toward the better accessibility of rapid prototyping technologies in the medical field. PMID:27003456

  11. MT3D: a 3 dimensional magnetotelluric modeling program (user's guide and documentation for Rev. 1)

    SciTech Connect

    Nutter, C.; Wannamaker, P.E.

    1980-11-01

    MT3D.REV1 is a non-interactive computer program written in FORTRAN to do 3-dimensional magnetotelluric modeling. A 3-D volume integral equation has been adapted to simulate the MT response of a 3D body in the earth. An integro-difference scheme has been incorporated to increase the accuracy. This is a user's guide for MT3D.REV1 on the University of Utah Research Institute's (UURI) PRIME 400 computer operating under PRIMOS IV, Rev. 17.

  12. Investigation of Asymmetries in Inductively Coupled Plasma Etching Reactors Using a 3-Dimensional Hybrid Model

    NASA Astrophysics Data System (ADS)

    Kushner, Mark J.; Grapperhaus, Michael J.

    1996-10-01

    Inductively Coupled Plasma (ICP) reactors have the potential for scaling to large area substrates while maintaining azimuthal symmetry or side-to-side uniformity across the wafer. Asymmetric etch properties in these devices have been attributed to transmission line properties of the coil, internal structures (such as wafer clamps) and non-uniform gas injection or pumping. To investigate the origins of asymmetric etch properties, a 3-dimensional hybrid model has been developed. The hybrid model contains electromagnetic, electric circuit, electron energy equation, and fluid modules. Continuity and momentum equations are solved in the fluid module along with Poisson's equation. We will discuss results for ion and radical flux uniformity to the substrate while varying the transmission line characteristics of the coil, symmetry of gas inlets/pumping, and internal structures. Comparisons will be made to expermental measurements of etch rates. ^*Work supported by SRC, NSF, ARPA/AFOSR and LAM Research.

  13. Using 3-dimensional printing to create presurgical models for endodontic surgery.

    PubMed

    Bahcall, James K

    2014-09-01

    Advances in endodontic surgery--from both a technological and procedural perspective-have been significant over the last 18 years. Although these technologies and procedural enhancements have significantly improved endodontic surgical treatment outcomes, there is still an ongoing challenge of overcoming the limitations of interpreting preoperative 2-dimensional (2-D) radiographic representation of a 3-dimensional (3-D) in vivo surgical field. Cone-beam Computed Tomography (CBCT) has helped to address this issue by providing a 3-D enhancement of the 2-D radiograph. The next logical step to further improve a presurgical case 3-D assessment is to create a surgical model from the CBCT scan. The purpose of this article is to introduce 3-D printing of CBCT scans for creating presurgical models for endodontic surgery. PMID:25197746

  14. The Investigation of Accuracy of 3 Dimensional Models Generated From Point Clouds with Terrestrial Laser Scanning

    NASA Astrophysics Data System (ADS)

    Gumus, Kutalmis; Erkaya, Halil

    2013-04-01

    In Terrestrial laser scanning (TLS) applications, it is necessary to take into consideration the conditions that affect the scanning process, especially the general characteristics of the laser scanner, geometric properties of the scanned object (shape, size, etc.), and its spatial location in the environment. Three dimensional models obtained with TLS, allow determining the geometric features and relevant magnitudes of the scanned object in an indirect way. In order to compare the spatial location and geometric accuracy of the 3-dimensional model created by Terrestrial laser scanning, it is necessary to use measurement tools that give more precise results than TLS. Geometric comparisons are performed by analyzing the differences between the distances, the angles between surfaces and the measured values taken from cross-sections between the data from the 3-dimensional model created with TLS and the values measured by other measurement devices The performance of the scanners, the size and shape of the scanned objects are tested using reference objects the sizes of which are determined with high precision. In this study, the important points to consider when choosing reference objects were highlighted. The steps up to processing the point clouds collected by scanning, regularizing these points and modeling in 3 dimensions was presented visually. In order to test the geometric correctness of the models obtained by Terrestrial laser scanners, sample objects with simple geometric shapes such as cubes, rectangular prisms and cylinders that are made of concrete were used as reference models. Three dimensional models were generated by scanning these reference models with Trimble Mensi GS 100. The dimension of the 3D model that is created from point clouds was compared with the precisely measured dimensions of the reference objects. For this purpose, horizontal and vertical cross-sections were taken from the reference objects and generated 3D models and the proximity of

  15. 3-Dimensional Geologic Modeling Applied to the Structural Characterization of Geothermal Systems: Astor Pass, Nevada, USA

    SciTech Connect

    Siler, Drew L; Faulds, James E; Mayhew, Brett

    2013-04-16

    Geothermal systems in the Great Basin, USA, are controlled by a variety of fault intersection and fault interaction areas. Understanding the specific geometry of the structures most conducive to broad-scale geothermal circulation is crucial to both the mitigation of the costs of geothermal exploration (especially drilling) and to the identification of geothermal systems that have no surface expression (blind systems). 3-dimensional geologic modeling is a tool that can elucidate the specific stratigraphic intervals and structural geometries that host geothermal reservoirs. Astor Pass, NV USA lies just beyond the northern extent of the dextral Pyramid Lake fault zone near the boundary between two distinct structural domains, the Walker Lane and the Basin and Range, and exhibits characteristics of each setting. Both northwest-striking, left-stepping dextral faults of the Walker Lane and kinematically linked northerly striking normal faults associated with the Basin and Range are present. Previous studies at Astor Pass identified a blind geothermal system controlled by the intersection of west-northwest and north-northwest striking dextral-normal faults. Wells drilled into the southwestern quadrant of the fault intersection yielded 94°C fluids, with geothermometers suggesting a maximum reservoir temperature of 130°C. A 3-dimensional model was constructed based on detailed geologic maps and cross-sections, 2-dimensional seismic data, and petrologic analysis of the cuttings from three wells in order to further constrain the structural setting. The model reveals the specific geometry of the fault interaction area at a level of detail beyond what geologic maps and cross-sections can provide.

  16. Simple computer program to model 3-dimensional underground heat flow with realistic boundary conditions

    NASA Astrophysics Data System (ADS)

    Metz, P. D.

    A FORTRAN computer program called GROCS (GRound Coupled Systems) has been developed to study 3-dimensional underground heat flow. Features include the use of up to 30 finite elements or blocks of Earth which interact via finite difference heat flow equations and a subprogram which sets realistic time and depth dependent boundary conditions. No explicit consideration of mositure movement or freezing is given. GROCS has been used to model the thermal behavior of buried solar heat storage tanks (with and without insulation) and serpentine pipe fields for solar heat pump space conditioning systems. The program is available independently or in a form compatible with specially written TRNSYS component TYPE subroutines. The approach taken in the design of GROCS, the mathematics contained and the program architecture, are described. Then, the operation of the stand-alone version is explained. Finally, the validity of GROCS is discussed.

  17. A 3-dimensional DTI MRI-based model of GBM growth and response to radiation therapy.

    PubMed

    Hathout, Leith; Patel, Vishal; Wen, Patrick

    2016-09-01

    Glioblastoma (GBM) is both the most common and the most aggressive intra-axial brain tumor, with a notoriously poor prognosis. To improve this prognosis, it is necessary to understand the dynamics of GBM growth, response to treatment and recurrence. The present study presents a mathematical diffusion-proliferation model of GBM growth and response to radiation therapy based on diffusion tensor (DTI) MRI imaging. This represents an important advance because it allows 3-dimensional tumor modeling in the anatomical context of the brain. Specifically, tumor infiltration is guided by the direction of the white matter tracts along which glioma cells infiltrate. This provides the potential to model different tumor growth patterns based on location within the brain, and to simulate the tumor's response to different radiation therapy regimens. Tumor infiltration across the corpus callosum is simulated in biologically accurate time frames. The response to radiation therapy, including changes in cell density gradients and how these compare across different radiation fractionation protocols, can be rendered. Also, the model can estimate the amount of subthreshold tumor which has extended beyond the visible MR imaging margins. When combined with the ability of being able to estimate the biological parameters of invasiveness and proliferation of a particular GBM from serial MRI scans, it is shown that the model has potential to simulate realistic tumor growth, response and recurrence patterns in individual patients. To the best of our knowledge, this is the first presentation of a DTI-based GBM growth and radiation therapy treatment model. PMID:27572745

  18. Assessment and Planning for a Pediatric Bilateral Hand Transplant Using 3-Dimensional Modeling: Case Report.

    PubMed

    Gálvez, Jorge A; Gralewski, Kevin; McAndrew, Christine; Rehman, Mohamed A; Chang, Benjamin; Levin, L Scott

    2016-03-01

    Children are not typically considered for hand transplantation for various reasons, including the difficulty of finding an appropriate donor. Matching donor-recipient hands and forearms based on size is critically important. If the donor's hands are too large, the recipient may not be able to move the fingers effectively. Conversely, if the donor's hands are too small, the appearance may not be appropriate. We present an 8-year-old child evaluated for a bilateral hand transplant following bilateral amputation. The recipient forearms and model hands were modeled from computed tomography imaging studies and replicated as anatomic models with a 3-dimensional printer. We modified the scale of the printed hand to produce 3 proportions, 80%, 100% and 120%. The transplant team used the anatomical models during evaluation of a donor for appropriate match based on size. The donor's hand size matched the 100%-scale anatomical model hand and the transplant team was activated. In addition to assisting in appropriate donor selection by the transplant team, the 100%-scale anatomical model hand was used to create molds for prosthetic hands for the donor. PMID:26810827

  19. Using Interior Point Method Optimization Techniques to Improve 2- and 3-Dimensional Models of Earth Structures

    NASA Astrophysics Data System (ADS)

    Zamora, A.; Gutierrez, A. E.; Velasco, A. A.

    2014-12-01

    2- and 3-Dimensional models obtained from the inversion of geophysical data are widely used to represent the structural composition of the Earth and to constrain independent models obtained from other geological data (e.g. core samples, seismic surveys, etc.). However, inverse modeling of gravity data presents a very unstable and ill-posed mathematical problem, given that solutions are non-unique and small changes in parameters (position and density contrast of an anomalous body) can highly impact the resulting model. Through the implementation of an interior-point method constrained optimization technique, we improve the 2-D and 3-D models of Earth structures representing known density contrasts mapping anomalous bodies in uniform regions and boundaries between layers in layered environments. The proposed techniques are applied to synthetic data and gravitational data obtained from the Rio Grande Rift and the Cooper Flat Mine region located in Sierra County, New Mexico. Specifically, we improve the 2- and 3-D Earth models by getting rid of unacceptable solutions (those that do not satisfy the required constraints or are geologically unfeasible) given the reduction of the solution space.

  20. 3-Dimensional Modeling of Capacitively and Inductively Coupled Plasma Etching Systems

    NASA Astrophysics Data System (ADS)

    Rauf, Shahid

    2008-10-01

    Low temperature plasmas are widely used for thin film etching during micro and nano-electronic device fabrication. Fluid and hybrid plasma models were developed 15-20 years ago to understand the fundamentals of these plasmas and plasma etching. These models have significantly evolved since then, and are now a major tool used for new plasma hardware design and problem resolution. Plasma etching is a complex physical phenomenon, where inter-coupled plasma, electromagnetic, fluid dynamics, and thermal effects all have a major influence. The next frontier in the evolution of fluid-based plasma models is where these models are able to self-consistently treat the inter-coupling of plasma physics with fluid dynamics, electromagnetics, heat transfer and magnetostatics. We describe one such model in this paper and illustrate its use in solving engineering problems of interest for next generation plasma etcher design. Our 3-dimensional plasma model includes the full set of Maxwell equations, transport equations for all charged and neutral species in the plasma, the Navier-Stokes equation for fluid flow, and Kirchhoff's equations for the lumped external circuit. This model also includes Monte Carlo based kinetic models for secondary electrons and stochastic heating, and can take account of plasma chemistry. This modeling formalism allows us to self-consistently treat the dynamics in commercial inductively and capacitively coupled plasma etching reactors with realistic plasma chemistries, magnetic fields, and reactor geometries. We are also able to investigate the influence of the distributed electromagnetic circuit at very high frequencies (VHF) on the plasma dynamics. The model is used to assess the impact of azimuthal asymmetries in plasma reactor design (e.g., off-center pump, 3D magnetic field, slit valve, flow restrictor) on plasma characteristics at frequencies from 2 -- 180 MHz. With Jason Kenney, Ankur Agarwal, Ajit Balakrishna, Kallol Bera, and Ken Collins.

  1. 3-DIMENSIONAL Numerical Modeling on the Combustion and Emission Characteristics of Biodiesel in Diesel Engines

    NASA Astrophysics Data System (ADS)

    Yang, Wenming; An, Hui; Amin, Maghbouli; Li, Jing

    2014-11-01

    A 3-dimensional computational fluid dynamics modeling is conducted on a direct injection diesel engine fueled by biodiesel using multi-dimensional software KIVA4 coupled with CHEMKIN. To accurately predict the oxidation of saturated and unsaturated agents of the biodiesel fuel, a multicomponent advanced combustion model consisting of 69 species and 204 reactions combined with detailed oxidation pathways of methyl decenoate (C11H22O2), methyl-9-decenoate (C11H20O2) and n-heptane (C7H16) is employed in this work. In order to better represent the real fuel properties, the detailed chemical and thermo-physical properties of biodiesel such as vapor pressure, latent heat of vaporization, liquid viscosity and surface tension were calculated and compiled into the KIVA4 fuel library. The nitrogen monoxide (NO) and carbon monoxide (CO) formation mechanisms were also embedded. After validating the numerical simulation model by comparing the in-cylinder pressure and heat release rate curves with experimental results, further studies have been carried out to investigate the effect of combustion chamber design on flow field, subsequently on the combustion process and performance of diesel engine fueled by biodiesel. Research has also been done to investigate the impact of fuel injector location on the performance and emissions formation of diesel engine.

  2. An Explicit 3-Dimensional Model for Reactive Transport of Nitrogen in Tile Drained Fields

    NASA Astrophysics Data System (ADS)

    Hill, D. J.; Valocchi, A. J.; Hudson, R. J.

    2001-12-01

    Recently, there has been increased interest in nitrate contamination of groundwater in the Midwest because of its link to surface water eutrophication, especially in the Gulf of Mexico. The vast majority of this nitrate is the product of biologically mediated transformation of fertilizers containing ammonia in the vadose zone of agricultural fields. For this reason, it is imperative that mathematical models, which can serve as useful tools to evaluate both the impact of agricultural fertilizer applications and nutrient-reducing management practices, are able to specifically address transport in the vadose zone. The development of a 3-dimensional explicit numerical model to simulate the movement and transformation of nitrogen species through the subsurface on the scale of an individual farm plot will be presented. At this scale, nitrogen fate and transport is controlled by a complex coupling among hydrologic, agricultural and biogeochemical processes. The nitrogen model is a component of a larger modeling effort that focuses upon conditions typical of those found in agricultural fields in Illinois. These conditions include non-uniform, multi-dimensional, transient flow in both saturated and unsaturated zones, geometrically complex networks of tile drains, coupled surface-subsurface-tile flow, and dynamic levels of dissolved oxygen in the soil profile. The advection-dispersion-reaction equation is solved using an operator-splitting approach, which is a flexible and straightforward strategy. Advection is modeled using a total variation diminishing scheme, dispersion is modeled using an alternating direction explicit method, and reactions are modeled using rate law equations. The model's stability and accuracy will be discussed, and test problems will be presented.

  3. Basement membrane proteins promote progression of intraepithelial neoplasia in 3-dimensional models of human stratified epithelium.

    PubMed

    Andriani, Frank; Garfield, Jackie; Fusenig, Norbert E; Garlick, Jonathan A

    2004-01-20

    We have developed novel 3-dimensional in vitro and in vivo tissue models that mimic premalignant disease of human stratified epithelium in order to analyze the stromal contribution of extracellular matrix and basement membrane proteins to the progression of intraepithelial neoplasia. Three-dimensional, organotypic cultures were grown either on a de-epidermalized human dermis with pre-existing basement membrane components on its surface (AlloDerm), on a Type I collagen gel that lacked basement membrane proteins or on polycarbonate membranes coated with purified extracellular matrix proteins. When tumor cells (HaCaT-II4) were mixed with normal keratinocytes (4:1/normals:HaCaT-II4), tumor cells selectively attached, persisted and proliferated at the dermal-epidermal interface in vitro and generated dysplastic tissues when transplanted to nude mice only when grown in the presence of the AlloDerm substrate. This stromal interface was permissive for tumor cell attachment due to the rapid assembly of structured basement membrane. When tumor cells were mixed with normal keratinocytes and grown on polycarbonate membranes coated with individual extracellular matrix or basement membrane components, selective attachment and significant intraepithelial expansion occurred only on laminin 1 and Type IV collagen-coated membranes. This preferential adhesion of tumor cells restricted the synthesis of laminin 5 to basal cells where it was deposited in a polarized distribution. Western blot analysis revealed that tumor cell attachment was not due to differences in the synthesis or processing of laminin 5. Thus, intraepithelial progression towards premalignant disease is dependent on the selective adhesion of cells with malignant potential to basement membrane proteins that provide a permissive template for their persistence and expansion. PMID:14648700

  4. Contributions of the Musculus Uvulae to Velopharyngeal Closure Quantified With a 3-Dimensional Multimuscle Computational Model.

    PubMed

    Inouye, Joshua M; Lin, Kant Y; Perry, Jamie L; Blemker, Silvia S

    2016-02-01

    The convexity of the dorsal surface of the velum is critical for normal velopharyngeal (VP) function and is largely attributed to the levator veli palatini (LVP) and musculus uvulae (MU). Studies have correlated a concave or flat nasal velar surface to symptoms of VP dysfunction including hypernasality and nasal air emission. In the context of surgical repair of cleft palates, the MU has been given relatively little attention in the literature compared with the larger LVP. A greater understanding of the mechanics of the MU will provide insight into understanding the influence of a dysmorphic MU, as seen in cleft palate, as it relates to VP function. The purpose of this study was to quantify the contributions of the MU to VP closure in a computational model. We created a novel 3-dimensional (3D) finite element model of the VP mechanism from magnetic resonance imaging data collected from an individual with healthy noncleft VP anatomy. The model components included the velum, posterior pharyngeal wall (PPW), LVP, and MU. Simulations were based on the muscle and soft tissue mechanical properties from the literature. We found that, similar to previous hypotheses, the MU acts as (i) a space-occupying structure and (ii) a velar extensor. As a space-occupying structure, the MU helps to nearly triple the midline VP contact length. As a velar extensor, the MU acting alone without the LVP decreases the VP distance 62%. Furthermore, activation of the MU decreases the LVP activation required for closure almost 3-fold, from 20% (without MU) to 8% (with MU). Our study suggests that any possible salvaging and anatomical reconstruction of viable MU tissue in a cleft patient may improve VP closure due to its mechanical function. In the absence or dysfunction of MU tissue, implantation of autologous or engineered tissues at the velar midline, as a possible substitute for the MU, may produce a geometric convexity more favorable to VP closure. In the future, more complex models will

  5. First Results from a Forward, 3-Dimensional Regional Model of a Transpressional San Andreas Fault System

    NASA Astrophysics Data System (ADS)

    Fitzenz, D. D.; Miller, S. A.

    2001-12-01

    We present preliminary results from a 3-dimensional fault interaction model, with the fault system specified by the geometry and tectonics of the San Andreas Fault (SAF) system. We use the forward model for earthquake generation on interacting faults of Fitzenz and Miller [2001] that incorporates the analytical solutions of Okada [85,92], GPS-constrained tectonic loading, creep compaction and frictional dilatancy [Sleep and Blanpied, 1994, Sleep, 1995], and undrained poro-elasticity. The model fault system is centered at the Big Bend, and includes three large strike-slip faults (each discretized into multiple subfaults); 1) a 300km, right-lateral segment of the SAF to the North, 2) a 200km-long left-lateral segment of the Garlock fault to the East, and 3) a 100km-long right-lateral segment of the SAF to the South. In the initial configuration, three shallow-dipping faults are also included that correspond to the thrust belt sub-parallel to the SAF. Tectonic loading is decomposed into basal shear drag parallel to the plate boundary with a 35mm yr-1 plate velocity, and East-West compression approximated by a vertical dislocation surface applied at the far-field boundary resulting in fault-normal compression rates in the model space about 4mm yr-1. Our aim is to study the long-term seismicity characteristics, tectonic evolution, and fault interaction of this system. We find that overpressured faults through creep compaction are a necessary consequence of the tectonic loading, specifically where high normal stress acts on long straight fault segments. The optimal orientation of thrust faults is a function of the strike-slip behavior, and therefore results in a complex stress state in the elastic body. This stress state is then used to generate new fault surfaces, and preliminary results of dynamically generated faults will also be presented. Our long-term aim is to target measurable properties in or around fault zones, (e.g. pore pressures, hydrofractures, seismicity

  6. 3-Dimensional Marine CSEM Modeling by Employing TDFEM with Parallel Solvers

    NASA Astrophysics Data System (ADS)

    Wu, X.; Yang, T.

    2013-12-01

    In this paper, parallel fulfillment is developed for forward modeling of the 3-Dimensional controlled source electromagnetic (CSEM) by using time-domain finite element method (TDFEM). Recently, a greater attention rises on research of hydrocarbon (HC) reservoir detection mechanism in the seabed. Since China has vast ocean resources, seeking hydrocarbon reservoirs become significant in the national economy. However, traditional methods of seismic exploration shown a crucial obstacle to detect hydrocarbon reservoirs in the seabed with a complex structure, due to relatively high acquisition costs and high-risking exploration. In addition, the development of EM simulations typically requires both a deep knowledge of the computational electromagnetics (CEM) and a proper use of sophisticated techniques and tools from computer science. However, the complexity of large-scale EM simulations often requires large memory because of a large amount of data, or solution time to address problems concerning matrix solvers, function transforms, optimization, etc. The objective of this paper is to present parallelized implementation of the time-domain finite element method for analysis of three-dimensional (3D) marine controlled source electromagnetic problems. Firstly, we established a three-dimensional basic background model according to the seismic data, then electromagnetic simulation of marine CSEM was carried out by using time-domain finite element method, which works on a MPI (Message Passing Interface) platform with exact orientation to allow fast detecting of hydrocarbons targets in ocean environment. To speed up the calculation process, SuperLU of an MPI (Message Passing Interface) version called SuperLU_DIST is employed in this approach. Regarding the representation of three-dimension seabed terrain with sense of reality, the region is discretized into an unstructured mesh rather than a uniform one in order to reduce the number of unknowns. Moreover, high-order Whitney

  7. In vitro 3-dimensional tumor model for radiosensitivity of HPV positive OSCC cell lines

    PubMed Central

    Zhang, Mei; Rose, Barbara; Lee, C Soon; Hong, Angela M

    2015-01-01

    The incidence of oropharyngeal squamous cell carcinoma (OSCC) is increasing due to the rising prevalence of human papillomavirus (HPV) positive OSCC. HPV positive OSCC is associated with better outcomes than HPV negative OSCC. Our aim was to explore the possibility that this favorable prognosis is due to the enhanced radiosensitivity of HPV positive OSCC. HPV positive OSCC cell lines were generated from the primary OSCCs of 2 patients, and corresponding HPV positive cell lines generated from nodal metastases following xenografting in nude mice. Monolayer and 3 dimensional (3D) culture techniques were used to compare the radiosensitivity of HPV positive lines with that of 2 HPV negative OSCC lines. Clonogenic and protein assays were used to measure survival post radiation. Radiation induced cell cycle changes were studied using flow cytometry. In both monolayer and 3D culture, HPV positive cells exhibited a heterogeneous appearance whereas HPV negative cells tended to be homogeneous. After irradiation, HPV positive cells had a lower survival in clonogenic assays and lower total protein levels in 3D cultures than HPV negative cells. Irradiated HPV positive cells showed a high proportion of cells in G1/S phase, increased apoptosis, an increased proliferation rate, and an inability to form 3D tumor clumps. In conclusion, HPV positive OSCC cells are more radiosensitive than HPV negative OSCC cells in vitro, supporting a more radiosensitive nature of HPV positive OSCC. PMID:26046692

  8. The 3-dimensional, 4-channel model of human visual sensitivity to grayscale scrambles.

    PubMed

    Silva, Andrew E; Chubb, Charles

    2014-08-01

    Previous research supports the claim that human vision has three dimensions of sensitivity to grayscale scrambles (textures composed of randomly scrambled mixtures of different grayscales). However, the preattentive mechanisms (called here "field-capture channels") that confer this sensitivity remain obscure. The current experiments sought to characterize the specific field-capture channels that confer this sensitivity using a task in which the participant is required to detect the location of a small patch of one type of grayscale scramble in an extended background of another type. Analysis of the results supports the existence of four field-capture channels: (1) the (previously characterized) "blackshot" channel, sharply tuned to the blackest grayscales; (2) a (previously unknown) "gray-tuned" field-capture channel whose sensitivity is zero for black rising sharply to maximum sensitivity for grayscales slightly darker than mid-gray then decreasing to half-height for brighter grayscales; (3) an "up-ramped" channel whose sensitivity is zero for black, increases linearly with increasing grayscale reaching a maximum near white; (4) a (complementary) "down-ramped" channel whose sensitivity is maximal for black, decreases linearly reaching a minimum near white. The sensitivity functions of field-capture channels (3) and (4) are linearly dependent; thus, these four field-capture channels collectively confer sensitivity to a 3-dimensional space of histogram variations. PMID:24932891

  9. Spheroid-based 3-dimensional culture models: Gene expression and functionality in head and neck cancer.

    PubMed

    Schmidt, Marianne; Scholz, Claus-Juergen; Polednik, Christine; Roller, Jeanette

    2016-04-01

    In the present study a panel of 12 head and neck cancer (HNSCC) cell lines were tested for spheroid formation. Since the size and morphology of spheroids is dependent on both cell adhesion and proliferation in the 3-dimensional (3D) context, morphology of HNSCC spheroids was related to expression of E-cadherin and the proliferation marker Ki67. In HNSCC cell lines the formation of tight regular spheroids was dependent on distinct E-cadherin expression levels in monolayer cultures, usually resulting in upregulation following aggregation into 3D structures. Cell lines expressing only low levels of E-cadherin in monolayers produced only loose cell clusters, frequently decreasing E-cadherin expression further upon aggregation. In these cell lines no epidermal growth factor receptor (EGFR) upregulation occurred and proliferation generally decreased in spheroids/aggregates independent of E-cadherin expression. In a second approach a global gene expression analysis of the larynx carcinoma cell line HLaC78 monolayer and the corresponding spheroids was performed. A global upregulation of gene expression in HLaC78 spheroids was related to genes involved in cell adhesion, cell junctions and cytochrome P450-mediated metabolism of xenobiotics. Downregulation was associated with genes controlling cell cycle, DNA-replication and DNA mismatch repair. Analyzing the expression of selected genes of each functional group in monolayer and spheroid cultures of all 12 cell lines revealed evidence for common gene expression shifts in genes controlling cell junctions, cell adhesion, cell cycle and DNA replication as well as genes involved in the cytochrome P450-mediated metabolism of xenobiotics. PMID:26797047

  10. 3-Dimensional modelling of chick embryo eye development and growth using high resolution magnetic resonance imaging.

    PubMed

    Goodall, Nicola; Kisiswa, Lilian; Prashar, Ankush; Faulkner, Stuart; Tokarczuk, Paweł; Singh, Krish; Erichsen, Jonathan T; Guggenheim, Jez; Halfter, Willi; Wride, Michael A

    2009-10-01

    Magnetic resonance imaging (MRI) is a powerful tool for generating 3-dimensional structural and functional image data. MRI has already proven valuable in creating atlases of mouse and quail development. Here, we have exploited high resolution MRI to determine the parameters necessary to acquire images of the chick embryo eye. Using a 9.4 Tesla (400 MHz) high field ultra-shielded and refrigerated magnet (Bruker), MRI was carried out on paraformaldehyde-fixed chick embryos or heads at E4, E6, E8, and E10. Image data were processed using established and custom packages (MRICro, ImageJ, ParaVision, Bruker and mri3dX). Voxel dimensions ranged from 62.5 microm to 117.2 microm. We subsequently used the images obtained from the MRI data in order to make precise measurements of chick embryo eye surface area, volume and axial length from E4 to E10. MRI was validated for accurate sizing of ocular tissue features by direct comparison with previously published literature. Furthermore, we demonstrate the utility of high resolution MRI for making accurate measurements of morphological changes due to experimental manipulation of chick eye development, thereby facilitating a better understanding of the effects on chick embryo eye development and growth of such manipulations. Chondroitin sulphate or heparin were microinjected into the vitreous cavity of the right eyes of each of 3 embryos at E5. At E10, embryos were fixed and various eye parameters (volume, surface area, axial length and equatorial diameter) were determined using MRI and normalised with respect to the un-injected left eyes. Statistically significant alterations in eye volume (p < 0.05; increases with chondroitin sulphate and decreases with heparin) and changes in vitreous homogeneity were observed in embryos following microinjection of glycosaminoglycans. Furthermore, in the heparin-injected eyes, significant disturbances at the vitreo-retinal boundary were observed as well as retinal folding and detachment

  11. Application of 3-Dimensional Printing Technology to Construct an Eye Model for Fundus Viewing Study

    PubMed Central

    Li, Xinhua; Gao, Zhishan; Yuan, Dongqing; Liu, Qinghuai

    2014-01-01

    Objective To construct a life-sized eye model using the three-dimensional (3D) printing technology for fundus viewing study of the viewing system. Methods We devised our schematic model eye based on Navarro's eye and redesigned some parameters because of the change of the corneal material and the implantation of intraocular lenses (IOLs). Optical performance of our schematic model eye was compared with Navarro's schematic eye and other two reported physical model eyes using the ZEMAX optical design software. With computer aided design (CAD) software, we designed the 3D digital model of the main structure of the physical model eye, which was used for three-dimensional (3D) printing. Together with the main printed structure, polymethyl methacrylate(PMMA) aspherical cornea, variable iris, and IOLs were assembled to a physical eye model. Angle scale bars were glued from posterior to periphery of the retina. Then we fabricated other three physical models with different states of ammetropia. Optical parameters of these physical eye models were measured to verify the 3D printing accuracy. Results In on-axis calculations, our schematic model eye possessed similar size of spot diagram compared with Navarro's and Bakaraju's model eye, much smaller than Arianpour's model eye. Moreover, the spherical aberration of our schematic eye was much less than other three model eyes. While in off- axis simulation, it possessed a bit higher coma and similar astigmatism, field curvature and distortion. The MTF curves showed that all the model eyes diminished in resolution with increasing field of view, and the diminished tendency of resolution of our physical eye model was similar to the Navarro's eye. The measured parameters of our eye models with different status of ametropia were in line with the theoretical value. Conclusions The schematic eye model we designed can well simulate the optical performance of the human eye, and the fabricated physical one can be used as a tool in fundus

  12. Comparison of 1-, 2-, and 3-dimensional modeling of the TFTR for nuclear radiation transport analysis

    SciTech Connect

    Ku, L.P.; Kolibal, J.G.; Liew, S.L.

    1985-09-01

    The computational models of the TFTR constructed for the radiation transport analysis for the Q approx. 1 demonstration are summarized and reviewed. These models can be characterized by the dimensionality required to describe the geometry, and by the numerical methods of solving the transport equation. Results obtained with these models in the test cell are compared and discussed.

  13. Development of a liquid jet model for implementation in a 3-dimensional Eularian analysis tool

    NASA Astrophysics Data System (ADS)

    Buschman, Francis X., III

    The ability to model the thermal behavior of a nuclear reactor is of utmost importance to the reactor designer. Condensation is an important phenomenon when modeling a reactor system's response to a Loss Of Coolant Accident (LOCA). Condensation is even more important with the use of passive safety systems which rely on condensation heat transfer for long term cooling. The increasing use of condensation heat transfer, including condensation on jets of water, in safety systems puts added pressure to correctly model this phenomenon with thermal-hydraulic system and sub-channel analysis codes. In this work, a stand alone module with which to simulate condensation on a liquid jet was developed and then implemented within a reactor vessel analysis code to improve that code's handling of jet condensation. It is shown that the developed liquid jet model vastly improves the ability of COBRA-TF to model condensation on turbulent liquid jets. The stand alone jet model and the coupled liquid jet COBRA-TF have been compared to experimental data. Jet condensation heat transfer experiments by Celata et al. with a variety of jet diameters, velocities, and subcooling were utilized to evaluate the models. A sensitivity study on the effects of noncondensables on jet condensation was also carried out using the stand alone jet model.

  14. [Rapid 3-Dimensional Models of Cerebral Aneurysm for Emergency Surgical Clipping].

    PubMed

    Konno, Takehiko; Mashiko, Toshihiro; Oguma, Hirofumi; Kaneko, Naoki; Otani, Keisuke; Watanabe, Eiju

    2016-08-01

    We developed a method for manufacturing solid models of cerebral aneurysms, with a shorter printing time than that involved in conventional methods, using a compact 3D printer with acrylonitrile-butadiene-styrene(ABS)resin. We further investigated the application and utility of this printing system in emergency clipping surgery. A total of 16 patients diagnosed with acute subarachnoid hemorrhage resulting from cerebral aneurysm rupture were enrolled in the present study. Emergency clipping was performed on the day of hospitalization. Digital Imaging and Communication in Medicine(DICOM)data obtained from computed tomography angiography(CTA)scans were edited and converted to stereolithography(STL)file formats, followed by the production of 3D models of the cerebral aneurysm by using the 3D printer. The mean time from hospitalization to the commencement of surgery was 242 min, whereas the mean time required for manufacturing the 3D model was 67 min. The average cost of each 3D model was 194 Japanese Yen. The time required for manufacturing the 3D models shortened to approximately 1 hour with increasing experience of producing 3D models. Favorable impressions for the use of the 3D models in clipping were reported by almost all neurosurgeons included in this study. Although 3D printing is often considered to involve huge costs and long manufacturing time, the method used in the present study requires shorter time and lower costs than conventional methods for manufacturing 3D cerebral aneurysm models, thus making it suitable for use in emergency clipping. PMID:27506842

  15. Visualization of the 3-dimensional flow around a model with the aid of a laser knife

    NASA Technical Reports Server (NTRS)

    Borovoy, V. Y.; Ivanov, V. V.; Orlov, A. A.; Kharchenko, V. N.

    1984-01-01

    A method for visualizing the three-dimensional flow around models of various shapes in a wind tunnel at a Mach number of 5 is described. A laser provides a planar light flux such that any plane through the model can be selectively illuminated. The shape of shock waves and separation regions is then determined by the intensity of light scattered by soot particles in the flow.

  16. High fidelity 3-dimensional models of beam-electron cloud interactions in circular accelerators

    NASA Astrophysics Data System (ADS)

    Feiz Zarrin Ghalam, Ali

    Electron cloud is a low-density electron profile created inside the vacuum chamber of circular machines with positively charged beams. Electron cloud limits the peak current of the beam and degrades the beams' quality through luminosity degradation, emittance growth and head to tail or bunch to bunch instability. The adverse effects of electron cloud on long-term beam dynamics becomes more and more important as the beams go to higher and higher energies. This problem has become a major concern in many future circular machines design like the Large Hadron Collider (LHC) under construction at European Center for Nuclear Research (CERN). Due to the importance of the problem several simulation models have been developed to model long-term beam-electron cloud interaction. These models are based on "single kick approximation" where the electron cloud is assumed to be concentrated at one thin slab around the ring. While this model is efficient in terms of computational costs, it does not reflect the real physical situation as the forces from electron cloud to the beam are non-linear contrary to this model's assumption. To address the existing codes limitation, in this thesis a new model is developed to continuously model the beam-electron cloud interaction. The code is derived from a 3-D parallel Particle-In-Cell (PIC) model (QuickPIC) originally used for plasma wakefield acceleration research. To make the original model fit into circular machines environment, betatron and synchrotron equations of motions have been added to the code, also the effect of chromaticity, lattice structure have been included. QuickPIC is then benchmarked against one of the codes developed based on single kick approximation (HEAD-TAIL) for the transverse spot size of the beam in CERN-LHC. The growth predicted by QuickPIC is less than the one predicted by HEAD-TAIL. The code is then used to investigate the effect of electron cloud image charges on the long-term beam dynamics, particularly on the

  17. Remanent magnetization and 3-dimensional density model of the Kentucky anomaly region

    NASA Technical Reports Server (NTRS)

    Mayhew, M. A.; Estes, R. H.; Myers, D. M.

    1984-01-01

    A three-dimensional model of the Kentucky body was developed to fit surface gravity and long wavelength aeromagnetic data. Magnetization and density parameters for the model are much like those of Mayhew et al (1982). The magnetic anomaly due to the model at satellite altitude is shown to be much too small by itself to account for the anomaly measured by Magsat. It is demonstrated that the source region for the satellite anomaly is considerably more extensive than the Kentucky body sensu stricto. The extended source region is modeled first using prismatic model sources and then using dipole array sources. Magnetization directions for the source region found by inversion of various combinations of scalar and vector data are found to be close to the main field direction, implying the lack of a strong remanent component. It is shown by simulation that in a case (such as this) where the geometry of the source is known, if a strong remanent component is present its direction is readily detectable, but by scalar data as readily as vector data.

  18. Anthropogenic contamination of a phreatic drinking water winning: 3-dimensional reactive transport modelling

    NASA Astrophysics Data System (ADS)

    Griffioen, J.; van der Grift, B.; Maas, D.; van den Brink, C.; Zaadnoordijk, J. W.

    2003-04-01

    Groundwater is contaminated at the regional scale by agricultural activities and atmospheric deposition. A 3-D transport model was set-up for a phreatic drinking water winning, where the groundwater composition was monitored accurately. The winning is situated at an area with unconsolidated Pleistocene deposits. The land use is nature and agriculture. Annual mass-balances were determined using a wide range of historic data. The modelling approach for the unsaturated zone was either simple box models (Cl, NO_3 and SO_4) or 1-D transport modelling using HYDRUS (Cd). The modelling approach for the saturated zone used a multiple solute version of MT3D, where denitrification associated with pyrite oxidation and sorption of Cd were included. The solute transport calculations were performed for the period 1950--2030. The results obtained for the year 2000 were used as input concentration for the period 2000--2030. A comparison between the calculated and the measured concentrations of groundwater abstracted for Cl, NO_3 and SO_4 yields the following. First, the input at the surface is rather well estimated. Second, the redox reactivity of the first two aquifers is negligible around the winning, which is confirmed by respiration experiments using anaerobically sampled aquifer sediments. The reactivity of the third aquifer, which is a marine deposit and lies at least 30 meters below surface, is considerable. The discrepancies between modelled and measured output are explained by lack of knowledge about the subsurface reactivity and/or wrong estimates of surface loading and leaching from the unsaturated zone. The patterns for other hydrogeochemical variables such as Ca, HCO_3 may further constrain this lack of knowledge. The results for Cd indicate that Cd becomes strongly retarded, despite the low reactivity of the sandy sediments. The winning is rather insensitive to Cd contamination (but the surface water drainage network is not). Two major uncertainties for input of Cd

  19. Surgical treatment for congenital kyphosis correction using both spinal navigation and a 3-dimensional model.

    PubMed

    Sugimoto, Yoshihisa; Tanaka, Masato; Nakahara, Ryuichi; Misawa, Haruo; Kunisada, Toshiyuki; Ozaki, Toshifumi

    2012-01-01

    An 11 year-old girl had 66 degrees of kyphosis in the thoracolumbar junction. For the purpose of planning for kyphosis correction, we created a 3-D, full-scale model of the spine and consulted spinal navigation. Three-dimensional models are generally used as tactile guides to verify the surgical approach and portray the anatomic relations specific to a given patient. We performed posterior fusion from Th10 to L3, and vertebral column resection of Th12 and L1. Screw entry points, directions, lengths and diameters were determined by reference to navigation. Both tools were useful in the bone resection. We could easily detect the posterior element to be resected using the 3D model. During the anterior bony resection, navigation helped us to check the disc level and anterior wall of the vertebrae, which were otherwise difficult to detect due to their depth in the surgical field. Thus, the combination of navigation and 3D models helped us to safely perform surgery for a patient with complex spinal deformity. PMID:23254585

  20. A simple and efficient quasi 3-dimensional viscoelastic model and software for simulation of tapping-mode atomic force microscopy

    PubMed Central

    2015-01-01

    Summary This paper introduces a quasi-3-dimensional (Q3D) viscoelastic model and software tool for use in atomic force microscopy (AFM) simulations. The model is based on a 2-dimensional array of standard linear solid (SLS) model elements. The well-known 1-dimensional SLS model is a textbook example in viscoelastic theory but is relatively new in AFM simulation. It is the simplest model that offers a qualitatively correct description of the most fundamental viscoelastic behaviors, namely stress relaxation and creep. However, this simple model does not reflect the correct curvature in the repulsive portion of the force curve, so its application in the quantitative interpretation of AFM experiments is relatively limited. In the proposed Q3D model the use of an array of SLS elements leads to force curves that have the typical upward curvature in the repulsive region, while still offering a very low computational cost. Furthermore, the use of a multidimensional model allows for the study of AFM tips having non-ideal geometries, which can be extremely useful in practice. Examples of typical force curves are provided for single- and multifrequency tapping-mode imaging, for both of which the force curves exhibit the expected features. Finally, a software tool to simulate amplitude and phase spectroscopy curves is provided, which can be easily modified to implement other controls schemes in order to aid in the interpretation of AFM experiments. PMID:26734515

  1. A simple and efficient quasi 3-dimensional viscoelastic model and software for simulation of tapping-mode atomic force microscopy

    DOE PAGESBeta

    Solares, Santiago D.

    2015-11-26

    This study introduces a quasi-3-dimensional (Q3D) viscoelastic model and software tool for use in atomic force microscopy (AFM) simulations. The model is based on a 2-dimensional array of standard linear solid (SLS) model elements. The well-known 1-dimensional SLS model is a textbook example in viscoelastic theory but is relatively new in AFM simulation. It is the simplest model that offers a qualitatively correct description of the most fundamental viscoelastic behaviors, namely stress relaxation and creep. However, this simple model does not reflect the correct curvature in the repulsive portion of the force curve, so its application in the quantitative interpretationmore » of AFM experiments is relatively limited. In the proposed Q3D model the use of an array of SLS elements leads to force curves that have the typical upward curvature in the repulsive region, while still offering a very low computational cost. Furthermore, the use of a multidimensional model allows for the study of AFM tips having non-ideal geometries, which can be extremely useful in practice. Examples of typical force curves are provided for single- and multifrequency tappingmode imaging, for both of which the force curves exhibit the expected features. Lastly, a software tool to simulate amplitude and phase spectroscopy curves is provided, which can be easily modified to implement other controls schemes in order to aid in the interpretation of AFM experiments.« less

  2. A simple and efficient quasi 3-dimensional viscoelastic model and software for simulation of tapping-mode atomic force microscopy

    SciTech Connect

    Solares, Santiago D.

    2015-11-26

    This study introduces a quasi-3-dimensional (Q3D) viscoelastic model and software tool for use in atomic force microscopy (AFM) simulations. The model is based on a 2-dimensional array of standard linear solid (SLS) model elements. The well-known 1-dimensional SLS model is a textbook example in viscoelastic theory but is relatively new in AFM simulation. It is the simplest model that offers a qualitatively correct description of the most fundamental viscoelastic behaviors, namely stress relaxation and creep. However, this simple model does not reflect the correct curvature in the repulsive portion of the force curve, so its application in the quantitative interpretation of AFM experiments is relatively limited. In the proposed Q3D model the use of an array of SLS elements leads to force curves that have the typical upward curvature in the repulsive region, while still offering a very low computational cost. Furthermore, the use of a multidimensional model allows for the study of AFM tips having non-ideal geometries, which can be extremely useful in practice. Examples of typical force curves are provided for single- and multifrequency tappingmode imaging, for both of which the force curves exhibit the expected features. Lastly, a software tool to simulate amplitude and phase spectroscopy curves is provided, which can be easily modified to implement other controls schemes in order to aid in the interpretation of AFM experiments.

  3. Observations and Modeling of 3-Dimensional Cloud and Aerosol Fields from the Multiangle SpectroPolarimetric Imager (MSPI)

    NASA Astrophysics Data System (ADS)

    Garay, M. J.; Diner, D. J.; Martonchik, J. V.; Davis, A. B.

    2011-12-01

    Knowledge of the detailed 3-dimensional structure of clouds and atmospheric aerosols is vital for correctly modeling their radiative effects and interpreting optical remote sensing measurements of scattered sunlight. We will describe a set of new observations made by the Multiangle SpectroPolarimetric Imager (MSPI) from the ground and from the NASA ER-2 aircraft. MSPI is being developed and tested at JPL as a payload for the preliminary Aerosol-Cloud-Ecosystems (PACE) satellite mission, which is expected to fly near the end of the decade. MSPI builds upon experience gained from the Multi-angle Imaging SpectroRadiometer (MISR) currently orbiting on NASA's Terra satellite. Ground-MSPI and Air-MSPI are two prototype cameras operating in the ultraviolet (UV) to the visible/near-infrared (VNIR) range mounted on gimbals that acquire imagery in a pushbroom fashion, including polarization in selected spectral bands with demonstrated high polarimetric accuracy (0.5% uncertainty in degree of linear polarization). The spatial resolution of Ground-MSPI is 1 m for objects at a distance of 3 km. From the operational altitude of the ER-2, Air-MSPI has a ground resolution of approximately 10 m at nadir. This resolution, coupled with good calibration and high polarimetric performance means that MSPI can be used to derive radiatively important parameters of aerosols and clouds using intensity and polarization information together. As part of the effort for developing retrieval algorithms for the instrument, we have employed an extremely flexible 3-dimensional vector radiative transfer code. We will show example imagery from both MSPI cameras and describe how these scenes are modeled using this code. We will also discuss some of the important unknowns and limitations of this observational approach.

  4. An approximate single fluid 3-dimensional magnetohydrodynamic equilibrium model with toroidal flow

    NASA Astrophysics Data System (ADS)

    Cooper, W. A.; Hirshman, S. P.; Chapman, I. T.; Brunetti, D.; Faustin, J. M.; Graves, J. P.; Pfefferlé, D.; Raghunathan, M.; Sauter, O.; Tran, T. M.; Aiba, N.

    2014-09-01

    An approximate model for a single fluid three-dimensional (3D) magnetohydrodynamic (MHD) equilibrium with pure isothermal toroidal flow with imposed nested magnetic flux surfaces is proposed. It recovers the rigorous toroidal rotation equilibrium description in the axisymmetric limit. The approximation is valid under conditions of nearly rigid or vanishing toroidal rotation in regions with significant 3D deformation of the equilibrium flux surfaces. Bifurcated helical core equilibrium simulations of long-lived modes in the MAST device demonstrate that the magnetic structure is only weakly affected by the flow but that the 3D pressure distortion is important. The pressure is displaced away from the major axis and therefore is not as noticeably helically deformed as the toroidal magnetic flux under the subsonic flow conditions measured in the experiment. The model invoked fails to predict any significant screening by toroidal plasma rotation of resonant magnetic perturbations in MAST free boundary computations.

  5. 3-DIMENSIONAL Geological Mapping and Modeling Activities at the Geological Survey of Norway

    NASA Astrophysics Data System (ADS)

    Jarna, A.; Bang-Kittilsen, A.; Haase, C.; Henderson, I. H. C.; Høgaas, F.; Iversen, S.; Seither, A.

    2015-10-01

    Geology and all geological structures are three-dimensional in space. Geology can be easily shown as four-dimensional when time is considered. Therefore GIS, databases, and 3D visualization software are common tools used by geoscientists to view, analyse, create models, interpret and communicate geological data. The NGU (Geological Survey of Norway) is the national institution for the study of bedrock, mineral resources, surficial deposits and groundwater and marine geology. The interest in 3D mapping and modelling has been reflected by the increase of number of groups and researches dealing with 3D in geology within NGU. This paper highlights 3D geological modelling techniques and the usage of these tools in bedrock, geophysics, urban and groundwater studies at NGU, same as visualisation of 3D online. The examples show use of a wide range of data, methods, software and an increased focus on interpretation and communication of geology in 3D. The goal is to gradually expand the geospatial data infrastructure to include 3D data at the same level as 2D.

  6. Evaluation of 3-Dimensional Superimposition Techniques on Various Skeletal Structures of the Head Using Surface Models

    PubMed Central

    Pazera, Pawel; Zorkun, Berna; Katsaros, Christos; Ludwig, Björn

    2015-01-01

    Objectives To test the applicability, accuracy, precision, and reproducibility of various 3D superimposition techniques for radiographic data, transformed to triangulated surface data. Methods Five superimposition techniques (3P: three-point registration; AC: anterior cranial base; AC + F: anterior cranial base + foramen magnum; BZ: both zygomatic arches; 1Z: one zygomatic arch) were tested using eight pairs of pre-existing CT data (pre- and post-treatment). These were obtained from non-growing orthodontic patients treated with rapid maxillary expansion. All datasets were superimposed by three operators independently, who repeated the whole procedure one month later. Accuracy was assessed by the distance (D) between superimposed datasets on three form-stable anatomical areas, located on the anterior cranial base and the foramen magnum. Precision and reproducibility were assessed using the distances between models at four specific landmarks. Non parametric multivariate models and Bland-Altman difference plots were used for analyses. Results There was no difference among operators or between time points on the accuracy of each superimposition technique (p>0.05). The AC + F technique was the most accurate (D<0.17 mm), as expected, followed by AC and BZ superimpositions that presented similar level of accuracy (D<0.5 mm). 3P and 1Z were the least accurate superimpositions (0.790.05), the detected structural changes differed significantly between different techniques (p<0.05). Bland-Altman difference plots showed that BZ superimposition was comparable to AC, though it presented slightly higher random error. Conclusions Superimposition of 3D datasets using surface models created from voxel data can provide accurate, precise, and reproducible results, offering also high efficiency and increased post-processing capabilities. In

  7. A 3-dimensional in vitro model of epithelioid granulomas induced by high aspect ratio nanomaterials

    PubMed Central

    2011-01-01

    Background The most common causes of granulomatous inflammation are persistent pathogens and poorly-degradable irritating materials. A characteristic pathological reaction to intratracheal instillation, pharyngeal aspiration, or inhalation of carbon nanotubes is formation of epithelioid granulomas accompanied by interstitial fibrosis in the lungs. In the mesothelium, a similar response is induced by high aspect ratio nanomaterials, including asbestos fibers, following intraperitoneal injection. This asbestos-like behaviour of some engineered nanomaterials is a concern for their potential adverse health effects in the lungs and mesothelium. We hypothesize that high aspect ratio nanomaterials will induce epithelioid granulomas in nonadherent macrophages in 3D cultures. Results Carbon black particles (Printex 90) and crocidolite asbestos fibers were used as well-characterized reference materials and compared with three commercial samples of multiwalled carbon nanotubes (MWCNTs). Doses were identified in 2D and 3D cultures in order to minimize acute toxicity and to reflect realistic occupational exposures in humans and in previous inhalation studies in rodents. Under serum-free conditions, exposure of nonadherent primary murine bone marrow-derived macrophages to 0.5 μg/ml (0.38 μg/cm2) of crocidolite asbestos fibers or MWCNTs, but not carbon black, induced macrophage differentiation into epithelioid cells and formation of stable aggregates with the characteristic morphology of granulomas. Formation of multinucleated giant cells was also induced by asbestos fibers or MWCNTs in this 3D in vitro model. After 7-14 days, macrophages exposed to high aspect ratio nanomaterials co-expressed proinflammatory (M1) as well as profibrotic (M2) phenotypic markers. Conclusions Induction of epithelioid granulomas appears to correlate with high aspect ratio and complex 3D structure of carbon nanotubes, not with their iron content or surface area. This model offers a time- and cost

  8. Global simulation of canopy scale sun-induced chlorophyll fluorescence with a 3 dimensional radiative transfer model

    NASA Astrophysics Data System (ADS)

    Kobayashi, H.; Yang, W.; Ichii, K.

    2015-12-01

    Global simulation of canopy scale sun-induced chlorophyll fluorescence with a 3 dimensional radiative transfer modelHideki Kobayashi, Wei Yang, and Kazuhito IchiiDepartment of Environmental Geochemical Cycle Research, Japan Agency for Marine-Earth Science and Technology3173-25, Showa-machi, Kanazawa-ku, Yokohama, Japan.Plant canopy scale sun-induced chlorophyll fluorescence (SIF) can be observed from satellites, such as Greenhouse gases Observation Satellite (GOSAT), Orbiting Carbon Observatory-2 (OCO-2), and Global Ozone Monitoring Experiment-2 (GOME-2), using Fraunhofer lines in the near infrared spectral domain [1]. SIF is used to infer photosynthetic capacity of plant canopy [2]. However, it is not well understoond how the leaf-level SIF emission contributes to the top of canopy directional SIF because SIFs observed by the satellites use the near infrared spectral domain where the multiple scatterings among leaves are not negligible. It is necessary to quantify the fraction of emission for each satellite observation angle. Absorbed photosynthetically active radiation of sunlit leaves are 100 times higher than that of shaded leaves. Thus, contribution of sunlit and shaded leaves to canopy scale directional SIF emission should also be quantified. Here, we show the results of global simulation of SIF using a 3 dimensional radiative transfer simulation with MODIS atmospheric (aerosol optical thickness) and land (land cover and leaf area index) products and a forest landscape data sets prepared for each land cover category. The results are compared with satellite-based SIF (e.g. GOME-2) and the gross primary production empirically estimated by FLUXNET and remote sensing data.

  9. The Integrated Medical Model

    NASA Technical Reports Server (NTRS)

    Butler, Douglas J.; Kerstman, Eric

    2010-01-01

    This slide presentation reviews the goals and approach for the Integrated Medical Model (IMM). The IMM is a software decision support tool that forecasts medical events during spaceflight and optimizes medical systems during simulations. It includes information on the software capabilities, program stakeholders, use history, and the software logic.

  10. Effect of Heat-Inactivated Clostridium sporogenes and Its Conditioned Media on 3-Dimensional Colorectal Cancer Cell Models.

    PubMed

    Bhave, Madhura Satish; Hassanbhai, Ammar Mansoor; Anand, Padmaja; Luo, Kathy Qian; Teoh, Swee Hin

    2015-01-01

    Traditional cancer treatments, such as chemotherapy and radiation therapy continue to have limited efficacy due to tumor hypoxia. While bacterial cancer therapy has the potential to overcome this problem, it comes with the risk of toxicity and infection. To circumvent these issues, this paper investigates the anti-tumor effects of non-viable bacterial derivatives of Clostridium sporogenes. These non-viable derivatives are heat-inactivated C. sporogenes bacteria (IB) and the secreted bacterial proteins in culture media, known as conditioned media (CM). In this project, the effects of IB and CM on CT26 and HCT116 colorectal cancer cells were examined on a 2-Dimensional (2D) and 3-Dimensional (3D) platform. IB significantly inhibited cell proliferation of CT26 to 6.3% of the control in 72 hours for the 2D monolayer culture. In the 3D spheroid culture, cell proliferation of HCT116 spheroids notably dropped to 26.2%. Similarly the CM also remarkably reduced the cell-proliferation of the CT26 cells to 2.4% and 20% in the 2D and 3D models, respectively. Interestingly the effect of boiled conditioned media (BCM) on the cells in the 3D model was less inhibitory than that of CM. Thus, the inhibitive effect of inactivated C. sporogenes and its conditioned media on colorectal cancer cells is established. PMID:26507312

  11. Effect of Heat-Inactivated Clostridium sporogenes and Its Conditioned Media on 3-Dimensional Colorectal Cancer Cell Models

    PubMed Central

    Bhave, Madhura Satish; Hassanbhai, Ammar Mansoor; Anand, Padmaja; Luo, Kathy Qian; Teoh, Swee Hin

    2015-01-01

    Traditional cancer treatments, such as chemotherapy and radiation therapy continue to have limited efficacy due to tumor hypoxia. While bacterial cancer therapy has the potential to overcome this problem, it comes with the risk of toxicity and infection. To circumvent these issues, this paper investigates the anti-tumor effects of non-viable bacterial derivatives of Clostridium sporogenes. These non-viable derivatives are heat-inactivated C. sporogenes bacteria (IB) and the secreted bacterial proteins in culture media, known as conditioned media (CM). In this project, the effects of IB and CM on CT26 and HCT116 colorectal cancer cells were examined on a 2-Dimensional (2D) and 3-Dimensional (3D) platform. IB significantly inhibited cell proliferation of CT26 to 6.3% of the control in 72 hours for the 2D monolayer culture. In the 3D spheroid culture, cell proliferation of HCT116 spheroids notably dropped to 26.2%. Similarly the CM also remarkably reduced the cell-proliferation of the CT26 cells to 2.4% and 20% in the 2D and 3D models, respectively. Interestingly the effect of boiled conditioned media (BCM) on the cells in the 3D model was less inhibitory than that of CM. Thus, the inhibitive effect of inactivated C. sporogenes and its conditioned media on colorectal cancer cells is established. PMID:26507312

  12. 3-dimensional Modeling of Electromagnetic and Physical Sources of Aziumuthal Nonuniformities in Inductively Coupled Plasmas for Deposition

    NASA Astrophysics Data System (ADS)

    Lu, Junqing; Keiter, Eric R.; Kushner, Mark J.

    1998-10-01

    Inductively Coupled Plasmas (ICPs) are being used for a variety of deposition processes for microelectronics fabrication. Of particular concern in scaling these devices to large areas is maintaining azimuthal symmetry of the reactant fluxes. Sources of nonuniformity may be physical (e.g., gas injection and side pumping) or electromagnetic (e.g., transmission line effects in the antennas). In this paper, a 3-dimensional plasma equipment model, HPEM-3D,(M. J. Kushner, J. Appl. Phys. v.82, 5312 (1997).) is used to investigate physical and electromagentic sources of azimuthal nonuniformities in deposition tools. An ionized metal physical vapor deposition (IMPVD) system will be investigated where transmission line effects in the coils produce an asymmetric plasma density. Long mean free path transport for sputtered neutrals and tensor conducitivities have been added to HPEM-3D to address this system. Since the coil generated ion flux drifts back to the target to sputter low ionization potential metal atoms, the asymmetry is reinforced by rapid ionization of the metal atoms.

  13. A Geometric Modelling Approach to Determining the Best Sensing Coverage for 3-Dimensional Acoustic Target Tracking in Wireless Sensor Networks

    PubMed Central

    Pashazadeh, Saeid; Sharifi, Mohsen

    2009-01-01

    Existing 3-dimensional acoustic target tracking methods that use wired/wireless networked sensor nodes to track targets based on four sensing coverage do not always compute the feasible spatio-temporal information of target objects. To investigate this discrepancy in a formal setting, we propose a geometric model of the target tracking problem alongside its equivalent geometric dual model that is easier to solve. We then study and prove some properties of dual model by exploiting its relationship with algebra. Based on these properties, we propose a four coverage axis line method based on four sensing coverage and prove that four sensing coverage always yields two dual correct answers; usually one of them is infeasible. By showing that the feasible answer can be only sometimes identified by using a simple time test method such as the one proposed by ourselves, we prove that four sensing coverage fails to always yield the feasible spatio-temporal information of a target object. We further prove that five sensing coverage always gives the feasible position of a target object under certain conditions that are discussed in this paper. We propose three extensions to four coverage axis line method, namely, five coverage extent point method, five coverage extended axis lines method, and five coverage redundant axis lines method. Computation and time complexities of all four proposed methods are equal in the worst cases as well as on average being equal to Θ(1) each. Proposed methods and proved facts about capabilities of sensing coverage degree in this paper can be used in all other methods of acoustic target tracking like Bayesian filtering methods. PMID:22423198

  14. A 3-Dimensional Model of Water-Bearing Sequences in the Dominguez Gap Region, Long Beach, California

    USGS Publications Warehouse

    Ponti, Daniel J.; Ehman, Kenneth D.; Edwards, Brian D.; Tinsley, John C., III; Hildenbrand, Thomas; Hillhouse, John W.; Hanson, Randall T.; McDougall, Kristen; Powell, Charles L.; Wan, Elmira; Land, Michael; Mahan, Shannon; Sarna-Wojcicki, Andrei M.

    2007-01-01

    A 3-dimensional computer model of the Quaternary sequence stratigraphy in the Dominguez gap region of Long Beach, California has been developed to provide a robust chronostratigraphic framework for hydrologic and tectonic studies. The model consists of 13 layers within a 16.5 by 16.1 km (10.25 by 10 mile) square area and extends downward to an altitude of -900 meters (-2952.76 feet). Ten sequences of late Pliocene to Holocene age are identified and correlated within the model. Primary data to build the model comes from five reference core holes, extensive high-resolution seismic data obtained in San Pedro Bay, and logs from several hundred water and oil wells drilled in the region. The model is best constrained in the vicinity of the Dominguez gap seawater intrusion barrier where a dense network of subsurface data exist. The resultant stratigraphic framework and geologic structure differs significantly from what has been proposed in earlier studies. An important new discovery from this approach is the recognition of ongoing tectonic deformation throughout nearly all of Quaternary time that has impacted the geometry and character of the sequences. Anticlinal folding along a NW-SE trend, probably associated with Quaternary reactivation of the Wilmington anticline, has uplifted and thinned deposits along the fold crest, which intersects the Dominguez gap seawater barrier near Pacific Coast Highway. A W-NW trending fault system that approximately parallels the fold crest has also been identified. This fault progressively displaces all but the youngest sequences down to the north and serves as the southern termination of the classic Silverado aquifer. Uplift and erosion of fining-upward paralic sequences along the crest of the young fold has removed or thinned many of the fine-grained beds that serve to protect the underlying Silverado aquifer from seawater contaminated shallow groundwater. As a result of this process, the potential exists for vertical migration of

  15. Three-Dimensional Radiobiologic Dosimetry: Application of Radiobiologic Modeling to Patient-Specific 3-Dimensional Imaging–Based Internal Dosimetry

    PubMed Central

    Prideaux, Andrew R.; Song, Hong; Hobbs, Robert F.; He, Bin; Frey, Eric C.; Ladenson, Paul W.; Wahl, Richard L.; Sgouros, George

    2010-01-01

    Phantom-based and patient-specific imaging-based dosimetry methodologies have traditionally yielded mean organ-absorbed doses or spatial dose distributions over tumors and normal organs. In this work, radiobiologic modeling is introduced to convert the spatial distribution of absorbed dose into biologically effective dose and equivalent uniform dose parameters. The methodology is illustrated using data from a thyroid cancer patient treated with radioiodine. Methods Three registered SPECT/CT scans were used to generate 3-dimensional images of radionuclide kinetics (clearance rate) and cumulated activity. The cumulated activity image and corresponding CT scan were provided as input into an EGSnrc-based Monte Carlo calculation: The cumulated activity image was used to define the distribution of decays, and an attenuation image derived from CT was used to define the corresponding spatial tissue density and composition distribution. The rate images were used to convert the spatial absorbed dose distribution to a biologically effective dose distribution, which was then used to estimate a single equivalent uniform dose for segmented volumes of interest. Equivalent uniform dose was also calculated from the absorbed dose distribution directly. Results We validate the method using simple models; compare the dose-volume histogram with a previously analyzed clinical case; and give the mean absorbed dose, mean biologically effective dose, and equivalent uniform dose for an illustrative case of a pediatric thyroid cancer patient with diffuse lung metastases. The mean absorbed dose, mean biologically effective dose, and equivalent uniform dose for the tumor were 57.7, 58.5, and 25.0 Gy, respectively. Corresponding values for normal lung tissue were 9.5, 9.8, and 8.3 Gy, respectively. Conclusion The analysis demonstrates the impact of radiobiologic modeling on response prediction. The 57% reduction in the equivalent dose value for the tumor reflects a high level of dose

  16. Use of 3-Dimensional Volumetric Modeling of Adrenal Gland Size in Patients with Primary Pigmented Nodular Adrenocortical Disease.

    PubMed

    Chrysostomou, P P; Lodish, M B; Turkbey, E B; Papadakis, G Z; Stratakis, C A

    2016-04-01

    Primary pigmented nodular adrenocortical disease (PPNAD) is a rare type of bilateral adrenal hyperplasia leading to hypercortisolemia. Adrenal nodularity is often appreciable with computed tomography (CT); however, accurate radiologic characterization of adrenal size in PPNAD has not been studied well. We used 3-dimensional (3D) volumetric analysis to characterize and compare adrenal size in PPNAD patients, with and without Cushing's syndrome (CS). Patients diagnosed with PPNAD and their family members with known mutations in PRKAR1A were screened. CT scans were used to create 3D models of each adrenal. Criteria for biochemical diagnosis of CS included loss of diurnal variation and/or elevated midnight cortisol levels, and paradoxical increase in urinary free cortisol and/or urinary 17-hydroxysteroids after dexamethasone administration. Forty-five patients with PPNAD (24 females, 27.8±17.6 years) and 8 controls (19±3 years) were evaluated. 3D volumetric modeling of adrenal glands was performed in all. Thirty-eight patients out of 45 (84.4%) had CS. Their mean adrenal volume was 8.1 cc±4.1, 7.2 cc±4.5 (p=0.643) for non-CS, and 8.0cc±1.6 for controls. Mean values were corrected for body surface area; 4.7 cc/kg/m(2)±2.2 for CS, and 3.9 cc/kg/m(2)±1.3 for non-CS (p=0.189). Adrenal volume and midnight cortisol in both groups was positively correlated, r=0.35, p=0.03. We conclude that adrenal volume measured by 3D CT in patients with PPNAD and CS was similar to those without CS, confirming empirical CT imaging-based observations. However, the association between adrenal volume and midnight cortisol levels may be used as a marker of who among patients with PPNAD may develop CS, something that routine CT cannot do. PMID:27065461

  17. The Integrated Medical Model

    NASA Technical Reports Server (NTRS)

    Kerstman, Eric; Minard, Charles; Saile, Lynn; Freiere deCarvalho, Mary; Myers, Jerry; Walton, Marlei; Butler, Douglas; Iyengar, Sriram; Johnson-Throop, Kathy; Baumann, David

    2010-01-01

    The goals of the Integrated Medical Model (IMM) are to develop an integrated, quantified, evidence-based decision support tool useful to crew health and mission planners and to help align science, technology, and operational activities intended to optimize crew health, safety, and mission success. Presentation slides address scope and approach, beneficiaries of IMM capabilities, history, risk components, conceptual models, development steps, and the evidence base. Space adaptation syndrome is used to demonstrate the model's capabilities.

  18. Normal growth and development of the lips: a 3-dimensional study from 6 years to adulthood using a geometric model

    PubMed Central

    FERRARIO, VIRGILIO F.; SFORZA, CHIARELLA; SCHMITZ, JOHANNES H.; CIUSA, VERONICA; COLOMBO, ANNA

    2000-01-01

    A 3-dimensional computerised system with landmark representation of the soft-tissue facial surface allows noninvasive and fast quantitative study of facial growth. The aims of the present investigation were (1) to provide reference data for selected dimensions of lips (linear distances and ratios, vermilion area, volume); (2) to quantify the relevant growth changes; and (3) to evaluate sex differences in growth patterns. The 3-dimensional coordinates of 6 soft-tissue landmarks on the lips were obtained by an optoelectronic instrument in a mixed longitudinal and cross-sectional study (2023 examinations in 1348 healthy subjects between 6 y of age and young adulthood). From the landmarks, several linear distances (mouth width, total vermilion height, total lip height, upper lip height), the vermilion height-to-mouth width ratio, some areas (vermilion of the upper lip, vermilion of the lower lip, total vermilion) and volumes (upper lip volume, lower lip volume, total lip volume) were calculated and averaged for age and sex. Male values were compared with female values by means of Student's t test. Within each age group all lip dimensions (distances, areas, volumes) were significantly larger in boys than in girls (P < 0.05), with some exceptions in the first age groups and coinciding with the earlier female growth spurt, whereas the vermilion height-to-mouth width ratio did not show a corresponding sexual dimorphism. Linear distances in girls had almost reached adult dimensions in the 13–14 y age group, while in boys a large increase was still to occur. The attainment of adult dimensions was faster in the upper than in the lower lip, especially in girls. The method used in the present investigation allowed the noninvasive evaluation of a large sample of nonpatient subjects, leading to the definition of 3-dimensional normative data. Data collected in the present study could represent a data base for the quantitative description of human lip morphology from childhood to

  19. Verification and transfer of thermal pollution model. Volume 3: Verification of 3-dimensional rigid-lid model

    NASA Technical Reports Server (NTRS)

    Lee, S. S.; Sengupta, S.; Nwadike, E. V.; Sinha, S. K.

    1982-01-01

    The six-volume report: describes the theory of a three dimensional (3-D) mathematical thermal discharge model and a related one dimensional (1-D) model, includes model verification at two sites, and provides a separate user's manual for each model. The 3-D model has two forms: free surface and rigid lid. The former, verified at Anclote Anchorage (FL), allows a free air/water interface and is suited for significant surface wave heights compared to mean water depth; e.g., estuaries and coastal regions. The latter, verified at Lake Keowee (SC), is suited for small surface wave heights compared to depth (e.g., natural or man-made inland lakes) because surface elevation has been removed as a parameter. These models allow computation of time-dependent velocity and temperature fields for given initial conditions and time-varying boundary conditions. The free-surface model also provides surface height variations with time.

  20. Verification and transfer of thermal pollution model. Volume 2: User's manual for 3-dimensional free-surface model

    NASA Technical Reports Server (NTRS)

    Lee, S. S.; Sengupta, S.; Tuann, S. Y.; Lee, C. R.

    1982-01-01

    The six-volume report: describes the theory of a three-dimensional (3-D) mathematical thermal discharge model and a related one-dimensional (1-D) model, includes model verification at two sites, and provides a separate user's manual for each model. The 3-D model has two forms: free surface and rigid lid. The former, verified at Anclote Anchorage (FL), allows a free air/water interface and is suited for significant surface wave heights compared to mean water depth; e.g., estuaries and coastal regions. The latter, verified at Lake Keowee (SC), is suited for small surface wave heights compared to depth. These models allow computation of time-dependent velocity and temperature fields for given initial conditions and time-varying boundary conditions.

  1. Integrated Medical Model Overview

    NASA Technical Reports Server (NTRS)

    Myers, J.; Boley, L.; Foy, M.; Goodenow, D.; Griffin, D.; Keenan, A.; Kerstman, E.; Melton, S.; McGuire, K.; Saile, L.; Shah, R.; Garcia, Y.; Sirmons. B.; Walton, M.; Reyes, D.

    2015-01-01

    The Integrated Medical Model (IMM) Project represents one aspect of NASA's Human Research Program (HRP) to quantitatively assess medical risks to astronauts for existing operational missions as well as missions associated with future exploration and commercial space flight ventures. The IMM takes a probabilistic approach to assessing the likelihood and specific outcomes of one hundred medical conditions within the envelope of accepted space flight standards of care over a selectable range of mission capabilities. A specially developed Integrated Medical Evidence Database (iMED) maintains evidence-based, organizational knowledge across a variety of data sources. Since becoming operational in 2011, version 3.0 of the IMM, the supporting iMED, and the expertise of the IMM project team have contributed to a wide range of decision and informational processes for the space medical and human research community. This presentation provides an overview of the IMM conceptual architecture and range of application through examples of actual space flight community questions posed to the IMM project.

  2. A 3-dimensional ray-trace model for predicting the performance of flashlamp-pumped laser amplifiers

    SciTech Connect

    Jancaitis, K.S.; Haney, S.W.; Munro, D.H.; Le Touze, G.; Cabourdin, O.

    1997-02-13

    We have developed a fully three-dimensional model for the performance of flashlamp pumped laser amplifiers. The model uses a reverse ray-trace technique to calculate the pumping of the laser glass by the flashlamp radiation. We have discovered several different methods by which we can speed up the calculation of the gain profile in a amplifier. The model predicts the energy-storage performance of the Beamlet amplifiers to better than 5%. This model will be used in the optimization of the National Ignition Facility (NIF) amplifier design.

  3. Transcriptional profiling of radiation damage and preventive treatments in a 3-dimensional (3D) human cell culture model of oral mucositis

    PubMed Central

    Lambros, Maria P.; DeSalvo, Michael K.; Moreno, Jonathan; Mulamalla, Hari Chandana; Kondapalli, Lavanya

    2015-01-01

    Cancer patients who receive radiation are often afflicted by oral mucositis, a debilitating disease, characterized by mouth sores and difficulty in swallowing. Oftentimes, cancer patients afflicted with mucositis must stop life-saving therapies. Thus it is very important to prevent mucositis before it develops. Using a validated organotypic model of human oral mucosa, a 3-dimensional cell culture model of human oral keratinocytes, it has been shown that a mixture (NAC–QYD) of N-acetyl cysteine (NAC) and a traditional Chinese medicine, Qingre Liyan decoction (QYD), prevented radiation damage (Lambros et al., 2014). Here we provide detailed methods and analysis of microarray data for non-irradiated and irradiated human oral mucosal tissue with and without pretreatment with NAC, QYD and NAC-QYD. The microarray data been deposited in Gene Expression Omnibus (GEO): GSE62397. These data can be used to further elucidate the mechanisms of irradiation damage in oral mucosa and its prevention. PMID:26697327

  4. Transcriptional profiling of radiation damage and preventive treatments in a 3-dimensional (3D) human cell culture model of oral mucositis.

    PubMed

    Lambros, Maria P; DeSalvo, Michael K; Moreno, Jonathan; Mulamalla, Hari Chandana; Kondapalli, Lavanya

    2015-12-01

    Cancer patients who receive radiation are often afflicted by oral mucositis, a debilitating disease, characterized by mouth sores and difficulty in swallowing. Oftentimes, cancer patients afflicted with mucositis must stop life-saving therapies. Thus it is very important to prevent mucositis before it develops. Using a validated organotypic model of human oral mucosa, a 3-dimensional cell culture model of human oral keratinocytes, it has been shown that a mixture (NAC-QYD) of N-acetyl cysteine (NAC) and a traditional Chinese medicine, Qingre Liyan decoction (QYD), prevented radiation damage (Lambros et al., 2014). Here we provide detailed methods and analysis of microarray data for non-irradiated and irradiated human oral mucosal tissue with and without pretreatment with NAC, QYD and NAC-QYD. The microarray data been deposited in Gene Expression Omnibus (GEO): GSE62397. These data can be used to further elucidate the mechanisms of irradiation damage in oral mucosa and its prevention. PMID:26697327

  5. 3DHYDROGEOCHEM: A 3-DIMENSIONAL MODEL OF DENSITY-DEPENDENT SUBSURFACE FLOW AND THERMAL MULTISPECIES-MULTICOMPONENT HYDROGEOCHEMICAL TRANSPORT

    EPA Science Inventory

    This report presents a three-dimensional finite-element numerical model designed to simulate chemical transport in subsurface systems with temperature effect taken into account. The three-dimensional model is developed to provide (1) a tool of application, with which one is able...

  6. User's manual for master: Modeling of aerodynamic surfaces by 3-dimensional explicit representation. [input to three dimensional computational fluid dynamics

    NASA Technical Reports Server (NTRS)

    Gibson, S. G.

    1983-01-01

    A system of computer programs was developed to model general three dimensional surfaces. Surfaces are modeled as sets of parametric bicubic patches. There are also capabilities to transform coordinates, to compute mesh/surface intersection normals, and to format input data for a transonic potential flow analysis. A graphical display of surface models and intersection normals is available. There are additional capabilities to regulate point spacing on input curves and to compute surface/surface intersection curves. Input and output data formats are described; detailed suggestions are given for user input. Instructions for execution are given, and examples are shown.

  7. The use of TOUGH2 for the LBL/USGS 3-dimensional site-scale model of Yucca Mountain, Nevada

    SciTech Connect

    Bodvarsson, G.; Chen, G.; Haukwa, C.; Kwicklis, E.

    1995-12-31

    The three-dimensional site-scale numerical model o the unsaturated zone at Yucca Mountain is under continuous development and calibration through a collaborative effort between Lawrence Berkeley Laboratory (LBL) and the United States Geological Survey (USGS). The site-scale model covers an area of about 30 km{sup 2} and is bounded by major fault zones to the west (Solitario Canyon Fault), east (Bow Ridge Fault) and perhaps to the north by an unconfirmed fault (Yucca Wash Fault). The model consists of about 5,000 grid blocks (elements) with nearly 20,000 connections between them; the grid was designed to represent the most prevalent geological and hydro-geological features of the site including major faults, and layering and bedding of the hydro-geological units. Submodels are used to investigate specific hypotheses and their importance before incorporation into the three-dimensional site-scale model. The primary objectives of the three-dimensional site-scale model are to: (1) quantify moisture, gas and heat flows in the ambient conditions at Yucca Mountain, (2) help in guiding the site-characterization effort (primarily by USGS) in terms of additional data needs and to identify regions of the mountain where sufficient data have been collected, and (3) provide a reliable model of Yucca Mountain that is validated by repeated predictions of conditions in new boreboles and the ESF and has therefore the confidence of the public and scientific community. The computer code TOUGH2 developed by K. Pruess at LBL was used along with the three-dimensional site-scale model to generate these results. In this paper, we also describe the three-dimensional site-scale model emphasizing the numerical grid development, and then show some results in terms of moisture, gas and heat flow.

  8. Direct measurement of the 3-dimensional DNA lesion distribution induced by energetic charged particles in a mouse model tissue.

    PubMed

    Mirsch, Johanna; Tommasino, Francesco; Frohns, Antonia; Conrad, Sandro; Durante, Marco; Scholz, Michael; Friedrich, Thomas; Löbrich, Markus

    2015-10-01

    Charged particles are increasingly used in cancer radiotherapy and contribute significantly to the natural radiation risk. The difference in the biological effects of high-energy charged particles compared with X-rays or γ-rays is determined largely by the spatial distribution of their energy deposition events. Part of the energy is deposited in a densely ionizing manner in the inner part of the track, with the remainder spread out more sparsely over the outer track region. Our knowledge about the dose distribution is derived solely from modeling approaches and physical measurements in inorganic material. Here we exploited the exceptional sensitivity of γH2AX foci technology and quantified the spatial distribution of DNA lesions induced by charged particles in a mouse model tissue. We observed that charged particles damage tissue nonhomogenously, with single cells receiving high doses and many other cells exposed to isolated damage resulting from high-energy secondary electrons. Using calibration experiments, we transformed the 3D lesion distribution into a dose distribution and compared it with predictions from modeling approaches. We obtained a radial dose distribution with sub-micrometer resolution that decreased with increasing distance to the particle path following a 1/r2 dependency. The analysis further revealed the existence of a background dose at larger distances from the particle path arising from overlapping dose deposition events from independent particles. Our study provides, to our knowledge, the first quantification of the spatial dose distribution of charged particles in biologically relevant material, and will serve as a benchmark for biophysical models that predict the biological effects of these particles. PMID:26392532

  9. Direct measurement of the 3-dimensional DNA lesion distribution induced by energetic charged particles in a mouse model tissue

    PubMed Central

    Mirsch, Johanna; Tommasino, Francesco; Frohns, Antonia; Conrad, Sandro; Durante, Marco; Scholz, Michael; Friedrich, Thomas; Löbrich, Markus

    2015-01-01

    Charged particles are increasingly used in cancer radiotherapy and contribute significantly to the natural radiation risk. The difference in the biological effects of high-energy charged particles compared with X-rays or γ-rays is determined largely by the spatial distribution of their energy deposition events. Part of the energy is deposited in a densely ionizing manner in the inner part of the track, with the remainder spread out more sparsely over the outer track region. Our knowledge about the dose distribution is derived solely from modeling approaches and physical measurements in inorganic material. Here we exploited the exceptional sensitivity of γH2AX foci technology and quantified the spatial distribution of DNA lesions induced by charged particles in a mouse model tissue. We observed that charged particles damage tissue nonhomogenously, with single cells receiving high doses and many other cells exposed to isolated damage resulting from high-energy secondary electrons. Using calibration experiments, we transformed the 3D lesion distribution into a dose distribution and compared it with predictions from modeling approaches. We obtained a radial dose distribution with sub-micrometer resolution that decreased with increasing distance to the particle path following a 1/r2 dependency. The analysis further revealed the existence of a background dose at larger distances from the particle path arising from overlapping dose deposition events from independent particles. Our study provides, to our knowledge, the first quantification of the spatial dose distribution of charged particles in biologically relevant material, and will serve as a benchmark for biophysical models that predict the biological effects of these particles. PMID:26392532

  10. New 3-dimensional CFD modeling of CO2 and H2S simultaneous stripping from water within PVDF hollow fiber membrane contactor

    NASA Astrophysics Data System (ADS)

    Bahlake, Ahmad; Farivar, Foad; Dabir, Bahram

    2016-07-01

    In this paper a 3-dimensional modeling of simultaneous stripping of carbon dioxide (CO2) and hydrogen sulfide (H2S) from water using hollow fiber membrane made of polyvinylidene fluoride is developed. The water, containing CO2 and H2S enters to the membrane as feed. At the same time, pure nitrogen flow in the shell side of a shell and tube hollow fiber as the solvent. In the previous methods of modeling hollow fiber membranes just one of the membranes was modeled and the results expand to whole shell and tube system. In this research the whole hollow fiber shell and tube module is modeled to reduce the errors. Simulation results showed that increasing the velocity of solvent flow and decreasing the velocity of the feed are leads to increase in the system yield. However the effect of the feed velocity on the process is likely more than the influence of changing the velocity of the gaseous solvent. In addition H2S stripping has higher yield in comparison with CO2 stripping. This model is compared to the previous modeling methods and shows that the new model is more accurate. Finally, the effect of feed temperature is studied using response surface method and the operating conditions of feed temperature, feed velocity, and solvent velocity is optimized according to synergistic effects. Simulation results show that, in the optimum operating conditions the removal percentage of H2S and CO2 are 27 and 21 % respectively.

  11. New 3-dimensional CFD modeling of CO2 and H2S simultaneous stripping from water within PVDF hollow fiber membrane contactor

    NASA Astrophysics Data System (ADS)

    Bahlake, Ahmad; Farivar, Foad; Dabir, Bahram

    2015-08-01

    In this paper a 3-dimensional modeling of simultaneous stripping of carbon dioxide (CO2) and hydrogen sulfide (H2S) from water using hollow fiber membrane made of polyvinylidene fluoride is developed. The water, containing CO2 and H2S enters to the membrane as feed. At the same time, pure nitrogen flow in the shell side of a shell and tube hollow fiber as the solvent. In the previous methods of modeling hollow fiber membranes just one of the membranes was modeled and the results expand to whole shell and tube system. In this research the whole hollow fiber shell and tube module is modeled to reduce the errors. Simulation results showed that increasing the velocity of solvent flow and decreasing the velocity of the feed are leads to increase in the system yield. However the effect of the feed velocity on the process is likely more than the influence of changing the velocity of the gaseous solvent. In addition H2S stripping has higher yield in comparison with CO2 stripping. This model is compared to the previous modeling methods and shows that the new model is more accurate. Finally, the effect of feed temperature is studied using response surface method and the operating conditions of feed temperature, feed velocity, and solvent velocity is optimized according to synergistic effects. Simulation results show that, in the optimum operating conditions the removal percentage of H2S and CO2 are 27 and 21 % respectively.

  12. Automated modeling of medical decisions.

    PubMed Central

    Egar, J. W.; Musen, M. A.

    1993-01-01

    We have developed a graph grammar and a graph-grammar derivation system that, together, generate decision-theoretic models from unordered lists of medical terms. The medical terms represent considerations in a dilemma that confronts the patient and the health-care provider. Our current grammar ensures that several desirable structural properties are maintained in all derived decision models. PMID:8130509

  13. 3-dimensional geometric modeling and parameter estimation of scoria cones of the San Francisco Volcanic Field, Arizona, USA

    NASA Astrophysics Data System (ADS)

    Király, E.; Székely, B.; Bata, T.; Lócsi, L.; Karátson, D.

    2009-04-01

    The almost global availability of medium- and high-resolution Digital Terrain Models (DTMs) paved the way of new approaches in volcanic geomorphology. The increasing importance of understanding of surface processes that act during the degradation of volcanic edifices also mean a demand for geometric modeling of their surface, in order to derive parameters from the topography that are suitable for further analysis. Our study area, the San Francisco Volcanic Field (SFVF), is a ca. 4500 km2-large volcanic region situated around the San Francisco stratovolcano at Flagstaff, Arizona (USA) that hosts some 600 scoria and lava domes, numerous lava flows with extensive volcanic ash deposits. Because of the wide range in size and age, as well as contrasting degradation of these volcanic features, several authors have analysed them in the last decades to derive general rules of their lowering. Morphometric parameters were determined that were expected to be suitable to fulfill this requirement. In his pioneering work, Wood (1980a,b) considered 40 scoria cones, while almost two decades later Hooper and Sheridan (1998) included 237 features in their study. Their manual morphometric analyses were based on topographic maps that are time consuming, therefore their limited scope can now be extended with the availability of digital data. In the initial phase of our project more than 300 cones were analysed using the classic approach (height of the cone, width of the cone and crater, etc.). Additionally the slope histogram were analysed in order to classify the cones into different evolutionary categories. These analyses led to the selection of a few volcanoes, that entered in the next processing phase. Firstly the derivation of parameters in two-dimensional approach were carried out. Horizontal and vertical cross sections were extracted from the DTM, and the resulting planar curves were analysed via parameter estimation. The horizontal planar outlines were approached with circles

  14. Catastrophic regime shifts in coral communities exposed to physical disturbances: simulation results from object-oriented 3-dimensional coral reef model.

    PubMed

    Tam, Tze-wai; Ang, Put O

    2009-07-21

    A 3-dimensional individual-based model, the ReefModel, was developed to simulate the dynamical structure of coral reef community using object-oriented techniques. Interactions among functional groups of reef organisms were simulated in the model. The behaviours of these organisms were described with simple mechanistic rules that were derived from their general behaviours (e.g. growing habits, competitive mechanisms, response to physical disturbance) observed in natural coral reef communities. The model was implemented to explore the effects of physical disturbance on the dynamical structure of a 3-coral community that was characterized with three functional coral groups: tabular coral, foliaceous coral and massive coral. Simulation results suggest that (i) the integration of physical disturbance and differential responses (disturbance sensitivity and growing habit) of corals plays an important role in structuring coral communities; (ii) diversity of coral communities can be maximal under intermediate level of acute physical disturbance; (iii) multimodality exists in the final states and dynamic regimes of individual coral group as well as coral community structure, which results from the influence of small random spatial events occurring during the interactions among the corals in the community, under acute and repeated physical disturbances. These results suggest that alternative stable states and catastrophic regime shifts may exist in a coral community under unstable physical environment. PMID:19306887

  15. Application of 3-dimensional printing in hand surgery for production of a novel bone reduction clamp.

    PubMed

    Fuller, Sam M; Butz, Daniel R; Vevang, Curt B; Makhlouf, Mansour V

    2014-09-01

    Three-dimensional printing is being rapidly incorporated in the medical field to produce external prosthetics for improved cosmesis and fabricated molds to aid in presurgical planning. Biomedically engineered products from 3-dimensional printers are also utilized as implantable devices for knee arthroplasty, airway orthoses, and other surgical procedures. Although at first expensive and conceptually difficult to construct, 3-dimensional printing is now becoming more affordable and widely accessible. In hand surgery, like many other specialties, new or customized instruments would be desirable; however, the overall production cost restricts their development. We are presenting our step-by-step experience in creating a bone reduction clamp for finger fractures using 3-dimensional printing technology. Using free, downloadable software, a 3-dimensional model of a bone reduction clamp for hand fractures was created based on the senior author's (M.V.M.) specific design, previous experience, and preferences for fracture fixation. Once deemed satisfactory, the computer files were sent to a 3-dimensional printing company for the production of the prototypes. Multiple plastic prototypes were made and adjusted, affording a fast, low-cost working model of the proposed clamp. Once a workable design was obtained, a printing company produced the surgical clamp prototype directly from the 3-dimensional model represented in the computer files. This prototype was used in the operating room, meeting the expectations of the surgeon. Three-dimensional printing is affordable and offers the benefits of reducing production time and nurturing innovations in hand surgery. This article presents a step-by-step description of our design process using online software programs and 3-dimensional printing services. As medical technology advances, it is important that hand surgeons remain aware of available resources, are knowledgeable about how the process works, and are able to take advantage of

  16. Cardiothoracic Applications of 3-dimensional Printing.

    PubMed

    Giannopoulos, Andreas A; Steigner, Michael L; George, Elizabeth; Barile, Maria; Hunsaker, Andetta R; Rybicki, Frank J; Mitsouras, Dimitris

    2016-09-01

    Medical 3-dimensional (3D) printing is emerging as a clinically relevant imaging tool in directing preoperative and intraoperative planning in many surgical specialties and will therefore likely lead to interdisciplinary collaboration between engineers, radiologists, and surgeons. Data from standard imaging modalities such as computed tomography, magnetic resonance imaging, echocardiography, and rotational angiography can be used to fabricate life-sized models of human anatomy and pathology, as well as patient-specific implants and surgical guides. Cardiovascular 3D-printed models can improve diagnosis and allow for advanced preoperative planning. The majority of applications reported involve congenital heart diseases and valvular and great vessels pathologies. Printed models are suitable for planning both surgical and minimally invasive procedures. Added value has been reported toward improving outcomes, minimizing perioperative risk, and developing new procedures such as transcatheter mitral valve replacements. Similarly, thoracic surgeons are using 3D printing to assess invasion of vital structures by tumors and to assist in diagnosis and treatment of upper and lower airway diseases. Anatomic models enable surgeons to assimilate information more quickly than image review, choose the optimal surgical approach, and achieve surgery in a shorter time. Patient-specific 3D-printed implants are beginning to appear and may have significant impact on cosmetic and life-saving procedures in the future. In summary, cardiothoracic 3D printing is rapidly evolving and may be a potential game-changer for surgeons. The imager who is equipped with the tools to apply this new imaging science to cardiothoracic care is thus ideally positioned to innovate in this new emerging imaging modality. PMID:27149367

  17. With the advent of domestic 3-dimensional (3D) printers and their associated reduced cost, is it now time for every medical school to have their own 3D printer?

    PubMed

    Balestrini, Christopher; Campo-Celaya, Tatiana

    2016-01-01

    Anatomy is the backbone of medical education and new techniques to improve learning are frequently explored. With the introduction of 3D printers specifically for the home market, the price of this technology has reached affordable levels. Using patient scan data, accurate 3D models can be printed that represent real human variation in anatomy to provide an innovative, inexpensive and valuable adjunct to anatomical teaching. Is it now time for every medical school to have their own 3D printer? PMID:26383082

  18. Hydroelectric structures studies using 3-dimensional methods

    SciTech Connect

    Harrell, T.R.; Jones, G.V.; Toner, C.K. )

    1989-01-01

    Deterioration and degradation of aged, hydroelectric project structures can significantly affect the operation and safety of a project. In many cases, hydroelectric headworks (in particular) have complicated geometrical configurations, loading patterns and hence, stress conditions. An accurate study of such structures can be performed using 3-dimensional computer models. 3-D computer models can be used for both stability evaluation and for finite element stress analysis. Computer aided engineering processes facilitate the use of 3-D methods in both pre-processing and post-processing of data. Two actual project examples are used to emphasize the authors' points.

  19. [Publishing models in medical journals].

    PubMed

    Reyes, Humberto B

    2012-02-01

    Medical journals are published by scientific societies, universities, publishing agencies and other for-profit or non-profit organizations. The traditional way to cover the expenses in printed journals has been a "subscribers pay" model. The rise of electronic versions in the internet, either together with the printed version or replacing it entirely, plus a progressive adherence to an "open access" for electronic versions, has created financial difficulties. Therefore, the "authors pay" model has been added. Both models can be subsidized by commercial or institutional advertising, but still a main source for financing relies either in subscriptions or in authors' payments. A small source of income that helps to cover publishing costs is a "charge for manuscript reception", currently applied by several journals. Those authors whose work has institutional or external support can use their grants to cover any charges, but the situation is more difficult for those who do not have such support. Since 1872, Sociedad Médica de Santiago-Chilean Society of Internal Medicine, owner and publisher of Revista Médica de Chile, has employed the "subscribers pay" model, subsidized by commercial advertising and temporary sponsors (Chilean government and others). The printed journal is reproduced in an open access electronic version, in www.scielo.cl. The increasing cost of both publications systems demands a time for reflection. PMID:22739959

  20. 3-dimensional bioprinting for tissue engineering applications.

    PubMed

    Gu, Bon Kang; Choi, Dong Jin; Park, Sang Jun; Kim, Min Sup; Kang, Chang Mo; Kim, Chun-Ho

    2016-01-01

    The 3-dimensional (3D) printing technologies, referred to as additive manufacturing (AM) or rapid prototyping (RP), have acquired reputation over the past few years for art, architectural modeling, lightweight machines, and tissue engineering applications. Among these applications, tissue engineering field using 3D printing has attracted the attention from many researchers. 3D bioprinting has an advantage in the manufacture of a scaffold for tissue engineering applications, because of rapid-fabrication, high-precision, and customized-production, etc. In this review, we will introduce the principles and the current state of the 3D bioprinting methods. Focusing on some of studies that are being current application for biomedical and tissue engineering fields using printed 3D scaffolds. PMID:27114828

  1. Teleportation of a 3-dimensional GHZ State

    NASA Astrophysics Data System (ADS)

    Cao, Hai-Jing; Wang, Huai-Sheng; Li, Peng-Fei; Song, He-Shan

    2012-05-01

    The process of teleportation of a completely unknown 3-dimensional GHZ state is considered. Three maximally entangled 3-dimensional Bell states function as quantum channel in the scheme. This teleportation scheme can be directly generalized to teleport an unknown d-dimensional GHZ state.

  2. Modeling Manipulation in Medical Education

    ERIC Educational Resources Information Center

    Dailey, Jason I.

    2010-01-01

    As residents and medical students progress through their medical training, they are presented with multiple instances in which they feel they must manipulate the healthcare system and deceive others in order to efficiently treat their patients. This, however, creates a culture of manipulation resulting in untoward effects on trainees' ethical and…

  3. 3-dimensional Oil Drift Simulations

    NASA Astrophysics Data System (ADS)

    Wettre, C.; Reistad, M.; Hjøllo, B.Å.

    Simulation of oil drift has been an ongoing activity at the Norwegian Meteorological Institute since the 1970's. The Marine Forecasting Centre provides a 24-hour service for the Norwegian Pollution Control Authority and the oil companies operating in the Norwegian sector. The response time is 30 minutes. From 2002 the service is extended to simulation of oil drift from oil spills in deep water, using the DeepBlow model developed by SINTEF Applied Chemistry. The oil drift model can be applied both for instantaneous and continuous releases. The changes in the mass of oil and emulsion as a result of evaporation and emulsion are computed. For oil spill at deep water, hydrate formation and gas dissolution are taken into account. The properties of the oil depend on the oil type, and in the present version 64 different types of oil can be simulated. For accurate oil drift simulations it is important to have the best possible data on the atmospheric and oceanic conditions. The oil drift simulations at the Norwegian Meteorological Institute are always based on the most updated data from numerical models of the atmosphere and the ocean. The drift of the surface oil is computed from the vectorial sum of the surface current from the ocean model and the wave induced Stokes drift computed from wave energy spectra from the wave prediction model. In the new model the current distribution with depth is taken into account when calculating the drift of the dispersed oil droplets. Salinity and temperature profiles from the ocean model are needed in the DeepBlow model. The result of the oil drift simulations can be plotted on sea charts used for navigation, either as trajectory plots or particle plots showing the situation at a given time. The results can also be sent as data files to be included in the user's own GIS system.

  4. 3DHYDROGEOCHEM: A 3-DIMENSIONAL MODEL OF DENSITY-DEPENDENT SUBSURFACE FLOW AND THERMAL MULTISPECIES-MULTICOMPONENT HYDROGEOCHEMICAL TRANSPORT (EPA/600/SR-98/159)

    EPA Science Inventory

    This report presents a three-dimensional finite-element numerical model designed to simulate chemical transport in subsurface systems with temperature effect taken into account. The three-dimensional model is developed to provide (1) a tool of application, with which one is able ...

  5. Phase diagram of quark-antiquark and diquark condensates in the 3-dimensional Gross-Neveu model with the 4-component spinor representation

    SciTech Connect

    Kohyama, Hiroaki

    2008-07-01

    We construct the phase diagram of the quark-antiquark and diquark condensates at finite temperature and density in the 2+1 dimensional (3D) two flavor massless Gross-Neveu (GN) model with the 4-component quarks. In contrast to the case of the 2-component quarks, there appears the coexisting phase of the quark-antiquark and diquark condensates. This is the crucial difference between the 2-component and 4-component quark cases in the 3D GN model. The coexisting phase is also seen in the 4D Nambu Jona-Lasinio model. Then we see that the 3D GN model with the 4-component quarks bears closer resemblance to the 4D Nambu Jona-Lasinio model.

  6. Numerical Simulation of Boiling Two-Phase Flow in Tight-Lattice Rod Bundle by 3-Dimensional Two-Fluid Model Code ACE-3D

    NASA Astrophysics Data System (ADS)

    Yoshida, Hiroyuki; Misawa, Takeharu; Takase, Kazuyuki

    Two-fluid model can simulate two-phase flow by computational cost less than detailed two-phase flow simulation method such as interface tracking method or particle interaction method. Therefore, two-fluid model is useful for thermal hydraulic analysis in large-scale domain such as a rod bundle. Japan Atomic Energy Agency (JAEA) develops three dimensional two-fluid model analysis code ACE-3D that adopts boundary fitted coordinate system in order to simulate complex shape flow channel. In this paper, boiling two-phase flow analysis in a tight-lattice rod bundle was performed by ACE-3D code. The parallel computation using 126 CPUs was applied to this analysis. In the results, the void fraction, which distributes in outermost region of rod bundle, is lower than that in center region of rod bundle. The tendency of void fraction distribution agreed with the measurement results by neutron radiography qualitatively. To evaluate effects of two-phase flow model used in ACE-3D code, numerical simulation of boiling two-phase in tight-lattice rod bundle with no lift force model was also performed. From the comparison of calculated results, it was concluded that the effects of lift force model were not so large for overall void fraction distribution of tight-lattice rod bundle. However, the lift force model is important for local void fraction distribution of fuel bundles.

  7. Utility of a 3-dimensional full-scale NaCl model for rib strut grafting for anterior fusion for cervicothoracic kyphosis

    PubMed Central

    Kobayashi, Kazuyoshi; Imagama, Shiro; Muramoto, Akio; Ito, Zenya; Ando, Kei; Yagi, Hideki; Hida, Tetsuro; Ito, Kenyu; Ishikawa, Yoshimoto; Tsushima, Mikito; Ishiguro, Naoki

    2015-01-01

    ABSTRACT In severe spinal deformity, pain and neurological disorder may be caused by spinal cord compression. Surgery for spinal reconstruction is desirable, but may be difficult in a case with severe deformity. Here, we show the utility of a 3D NaCl (salt) model in preoperative planning of anterior reconstruction using a rib strut in a 49-year-old male patient with cervicothoracic degenerative spondylosis. We performed surgery in two stages: a posterior approach with decompression and posterior instrumentation with a pedicle screw; followed by a second operation using an anterior approach, for which we created a 3D NaCl model including the cervicothoracic lesion, spinal deformity, and ribs for anterior reconstruction. The 3D NaCl model was easily scraped compared with a conventional plaster model and was useful for planning of resection and identification of a suitable rib for grafting in a preoperative simulation. Surgery was performed successfully with reference to the 3D NaCl model. We conclude that preoperative simulation with a 3D NaCl model contributes to performance of anterior reconstruction using a rib strut in a case of cervicothoracic deformity. PMID:26412901

  8. Distinction of Green Sweet Peppers by Using Various Color Space Models and Computation of 3 Dimensional Location Coordinates of Recognized Green Sweet Peppers Based on Parallel Stereovision System

    NASA Astrophysics Data System (ADS)

    Bachche, Shivaji; Oka, Koichi

    2013-06-01

    This paper presents the comparative study of various color space models to determine the suitable color space model for detection of green sweet peppers. The images were captured by using CCD cameras and infrared cameras and processed by using Halcon image processing software. The LED ring around the camera neck was used as an artificial lighting to enhance the feature parameters. For color images, CieLab, YIQ, YUV, HSI and HSV whereas for infrared images, grayscale color space models were selected for image processing. In case of color images, HSV color space model was found more significant with high percentage of green sweet pepper detection followed by HSI color space model as both provides information in terms of hue/lightness/chroma or hue/lightness/saturation which are often more relevant to discriminate the fruit from image at specific threshold value. The overlapped fruits or fruits covered by leaves can be detected in better way by using HSV color space model as the reflection feature from fruits had higher histogram than reflection feature from leaves. The IR 80 optical filter failed to distinguish fruits from images as filter blocks useful information on features. Computation of 3D coordinates of recognized green sweet peppers was also conducted in which Halcon image processing software provides location and orientation of the fruits accurately. The depth accuracy of Z axis was examined in which 500 to 600 mm distance between cameras and fruits was found significant to compute the depth distance precisely when distance between two cameras maintained to 100 mm.

  9. Fingernail Injuries and NASA's Integrated Medical Model

    NASA Technical Reports Server (NTRS)

    Kerstman, Eric; Butler, Doug

    2008-01-01

    The goal of space medicine is to optimize both crew health and performance. Currently, expert opinion is primarily relied upon for decision-making regarding medical equipment and supplies flown in space. Evidence-based decisions are preferred due to mass and volume limitations and the expense of space flight. The Integrated Medical Model (IMM) is an attempt to move us in that direction!

  10. A Structural Model of Medical Student Achievement.

    ERIC Educational Resources Information Center

    Sheehan, T. Joseph; Sanford, Keat

    1990-01-01

    The theoretical model of medical student performance begins with 38 measures, reduced to 18 without loss of information. These measures are shown to reflect five underlying theoretical interrelated variables: medical knowledge; clinical performance; science aptitude; college achievement; and attitudes and values. Results should be useful in…

  11. The Spatiotemporal Stability of Dominant Frequency Sites in In-Silico Modeling of 3-Dimensional Left Atrial Mapping of Atrial Fibrillation

    PubMed Central

    Hwang, Minki; Song, Jun-Seop; Lee, Young-Seon; Joung, Boyoung; Pak, Hui-Nam

    2016-01-01

    Background We previously reported that stable rotors were observed in in-silico human atrial fibrillation (AF) models, and were well represented by dominant frequency (DF). We explored the spatiotemporal stability of DF sites in 3D-AF models imported from patient CT images of the left atrium (LA). Methods We integrated 3-D CT images of the LA obtained from ten patients with persistent AF (male 80%, 61.8 ± 13.5 years old) into an in-silico AF model. After induction, we obtained 6 seconds of AF simulation data for DF analyses in 30 second intervals (T1–T9). The LA was divided into ten sections. Spatiotemporal changes and variations in the temporal consistency of DF were evaluated at each section of the LA. The high DF area was defined as the area with the highest 10% DF. Results 1. There was no spatial consistency in the high DF distribution at each LA section during T1–T9 except in one patient (p = 0.027). 2. Coefficients of variation for the high DF area were highly different among the ten LA sections (p < 0.001), and they were significantly higher in the four pulmonary vein (PV) areas, the LA appendage, and the peri-mitral area than in the other LA sections (p < 0.001). 3. When we conducted virtual ablation of 10%, 15%, and 20% of the highest DF areas (n = 270 cases), AF was changed to atrial tachycardia (AT) or terminated at a rate of 40%, 57%, and 76%, respectively. Conclusions Spatiotemporal consistency of the DF area was observed in 10% of AF patients, and high DF areas were temporally variable. Virtual ablation of DF is moderately effective in AF termination and AF changing into AT. PMID:27459377

  12. Wear particles derived from metal hip implants induce the generation of multinucleated giant cells in a 3-dimensional peripheral tissue-equivalent model.

    PubMed

    Dutta, Debargh K; Potnis, Pushya A; Rhodes, Kelly; Wood, Steven C

    2015-01-01

    Multinucleate giant cells (MGCs) are formed by the fusion of 5 to 15 monocytes or macrophages. MGCs can be generated by hip implants at the site where the metal surface of the device is in close contact with tissue. MGCs play a critical role in the inflammatory processes associated with adverse events such as aseptic loosening of the prosthetic joints and bone degeneration process called osteolysis. Upon interaction with metal wear particles, endothelial cells upregulate pro-inflammatory cytokines and other factors that enhance a localized immune response. However, the role of endothelial cells in the generation of MGCs has not been completely investigated. We developed a three-dimensional peripheral tissue-equivalent model (PTE) consisting of collagen gel, supporting a monolayer of endothelial cells and human peripheral blood mononuclear cells (PBMCs) on top, which mimics peripheral tissue under normal physiological conditions. The cultures were incubated for 14 days with Cobalt chromium alloy (CoCr ASTM F75, 1-5 micron) wear particles. PBMC were allowed to transit the endothelium and harvested cells were analyzed for MGC generation via flow cytometry. An increase in forward scatter (cell size) and in the propidium iodide (PI) uptake (DNA intercalating dye) was used to identify MGCs. Our results show that endothelial cells induce the generation of MGCs to a level 4 fold higher in 3-dimentional PTE system as compared to traditional 2-dimensional culture plates. Further characterization of MGCs showed upregulated expression of tartrate resistant alkaline phosphatase (TRAP) and dendritic cell specific transmembrane protein, (DC-STAMP), which are markers of bone degrading cells called osteoclasts. In sum, we have established a robust and relevant model to examine MGC and osteoclast formation in a tissue like environment using flow cytometry and RT-PCR. With endothelial cells help, we observed a consistent generation of metal wear particle- induced MGCs, which heralds

  13. Analytical modeling of worldwide medical radiation use

    SciTech Connect

    Mettler, F.A. Jr.; Davis, M.; Kelsey, C.A.; Rosenberg, R.; Williams, A.

    1987-02-01

    An analytical model was developed to estimate the availability and frequency of medical radiation use on a worldwide basis. This model includes medical and dental x-ray, nuclear medicine, and radiation therapy. The development of an analytical model is necessary as the first step in estimating the radiation dose to the world's population from this source. Since there is no data about the frequency of medical radiation use in more than half the countries in the world and only fragmentary data in an additional one-fourth of the world's countries, such a model can be used to predict the uses of medical radiation in these countries. The model indicates that there are approximately 400,000 medical x-ray machines worldwide and that approximately 1.2 billion diagnostic medical x-ray examinations are performed annually. Dental x-ray examinations are estimated at 315 million annually and approximately 22 million in-vivo diagnostic nuclear medicine examinations. Approximately 4 million radiation therapy procedures or courses of treatment are undertaken annually.

  14. A model for teaching medical ethics.

    PubMed

    Welbourn, R B

    1985-03-01

    The approach to teaching employed in the Dictionary of Medical Ethics (1) provides a model which might be adopted in other media. Most of the 150 authors were medical, but many represented other disciplines, and they wrote for similar professionals and for the general public. Medical ethics is derived from medical science and practice, moral philosophy, sociology, theology, the law and other disciplines, all of which make essential, distinctive and complementary contributions to knowledge and to teaching. Medical practitioners must play the primary role, because they are responsible for clinical ethical decisions, but they need the co-operation and guidance of others. All who are concerned should work towards the development of a general moral consensus among the profession and public, which keeps abreast of scientific and technical advances and to which all are committed. PMID:3884814

  15. Multilingual Medical Data Models in ODM Format

    PubMed Central

    Breil, B.; Kenneweg, J.; Fritz, F.; Bruland, P.; Doods, D.; Trinczek, B.; Dugas, M.

    2012-01-01

    Background Semantic interoperability between routine healthcare and clinical research is an unsolved issue, as information systems in the healthcare domain still use proprietary and site-specific data models. However, information exchange and data harmonization are essential for physicians and scientists if they want to collect and analyze data from different hospitals in order to build up registries and perform multicenter clinical trials. Consequently, there is a need for a standardized metadata exchange based on common data models. Currently this is mainly done by informatics experts instead of medical experts. Objectives We propose to enable physicians to exchange, rate, comment and discuss their own medical data models in a collaborative web-based repository of medical forms in a standardized format. Methods Based on a comprehensive requirement analysis, a web-based portal for medical data models was specified. In this context, a data model is the technical specification (attributes, data types, value lists) of a medical form without any layout information. The CDISC Operational Data Model (ODM) was chosen as the appropriate format for the standardized representation of data models. The system was implemented with Ruby on Rails and applies web 2.0 technologies to provide a community based solution. Forms from different source systems – both routine care and clinical research – were converted into ODM format and uploaded into the portal. Results A portal for medical data models based on ODM-files was implemented (http://www.medical-data-models.org). Physicians are able to upload, comment, rate and download medical data models. More than 250 forms with approximately 8000 items are provided in different views (overview and detailed presentation) and in multiple languages. For instance, the portal contains forms from clinical and research information systems. Conclusion The portal provides a system-independent repository for multilingual data models in ODM

  16. 3-dimensional imaging at nanometer resolutions

    DOEpatents

    Werner, James H.; Goodwin, Peter M.; Shreve, Andrew P.

    2010-03-09

    An apparatus and method for enabling precise, 3-dimensional, photoactivation localization microscopy (PALM) using selective, two-photon activation of fluorophores in a single z-slice of a sample in cooperation with time-gated imaging for reducing the background radiation from other image planes to levels suitable for single-molecule detection and spatial location, are described.

  17. The 3-dimensional cellular automata for HIV infection

    NASA Astrophysics Data System (ADS)

    Mo, Youbin; Ren, Bin; Yang, Wencao; Shuai, Jianwei

    2014-04-01

    The HIV infection dynamics is discussed in detail with a 3-dimensional cellular automata model in this paper. The model can reproduce the three-phase development, i.e., the acute period, the asymptotic period and the AIDS period, observed in the HIV-infected patients in a clinic. We show that the 3D HIV model performs a better robustness on the model parameters than the 2D cellular automata. Furthermore, we reveal that the occurrence of a perpetual source to successively generate infectious waves to spread to the whole system drives the model from the asymptotic state to the AIDS state.

  18. Biochemical Applications Of 3-Dimensional Fluorescence Spectrometry

    NASA Astrophysics Data System (ADS)

    Leiner, Marc J.; Wolfbeis, Otto S.

    1988-06-01

    We investigated the 3-dimensional fluorescence of complex mixtures of bioloquids such as human serum, serum ultrafiltrate, human urine, and human plasma low density lipoproteins. The total fluorescence of human serum can be divided into a few peaks. When comparing fluorescence topograms of sera, from normal and cancerous subjects, we found significant differences in tryptophan fluorescence. Although the total fluorescence of human urine can be resolved into 3-5 distinct peaks, some of them. do not result from single fluorescent urinary metabolites, but rather from. several species having similar spectral properties. Human plasma, low density lipoproteins possess a native fluorescence that changes when submitted to in-vitro autoxidation. The 3-dimensional fluorescence demonstrated the presence of 7 fluorophores in the lipid domain, and 6 fluorophores in the protein. dovain- The above results demonstrated that 3-dimensional fluorescence can resolve the spectral properties of complex ,lxtures much better than other methods. Moreover, other parameters than excitation and emission wavelength and intensity (for instance fluorescence lifetime, polarization, or quenchability) may be exploited to give a multidl,ensio,a1 matrix, that is unique for each sample. Consequently, 3-dimensio:Hhal fluorescence as such, or in combination with separation techniques is therefore considered to have the potential of becoming a useful new H.ethod in clinical chemistry and analytical biochemistry.

  19. A Database Model for Medical Consultation.

    ERIC Educational Resources Information Center

    Anvari, Morteza

    1991-01-01

    Describes a relational data model that can be used for knowledge representation and manipulation in rule-based medical consultation systems. Fuzzy queries or attribute values and fuzzy set theory are discussed, functional dependencies are described, and an example is presented of a system for diagnosing causes of eye inflammation. (15 references)…

  20. [New business model for medical specialists].

    PubMed

    Houwen, L G H J Louis

    2013-01-01

    The reforms in the field of medical specialist care have important implications for the professional practice of medical specialists and their working relationship with the hospital. This leads to a considerable amount of pressure placed upon the way physicians have traditionally practiced their liberal professions, which is by forming partnerships and practicing from within the hospitals based on an admission agreement. As of 2015, the tax benefits for entrepreneurs will be abolished and the formation of regional partnerships will be discouraged. These developments not only pose threats but also offer opportunities for both the entrepreneurial medical specialist and the innovative hospital. In this article, the prospect of a future business model for specialist medical care will be outlined and explored by proposing three new organizational forms. The central vision of this model is that physicians who wish to retain their status of liberal professional practitioners in the twenty-first century should be more involved in the ownership structure of hospitals. The social importance of responsible patient care remains paramount. PMID:23985238

  1. The shared medical appointment: a proposed model of medical appointments.

    PubMed

    Rhee, Eugene; Baum, Neil

    2013-01-01

    Today's healthcare providers are struggling more than ever with providing high-quality care and while controlling the spiraling costs of healthcare. The demands of an aging population, combined with a shrinking pool of medical personnel, have brought challenges to the medical office where doctors are saddled with the need of improving access to medical care. Recruiting new partners, using physician assistants and nurse practitioners, and seeing more patients in a workday are some ways doctors are trying to meet these challenges. For the most part, that does not solve the problems afflicting most physicians and practices. This article will discuss the concept of the shared medical appointment and how it might be applied to most medical practices. PMID:24765735

  2. The Integrated Medical Model: A Probabilistic Simulation Model Predicting In-Flight Medical Risks

    NASA Technical Reports Server (NTRS)

    Keenan, Alexandra; Young, Millennia; Saile, Lynn; Boley, Lynn; Walton, Marlei; Kerstman, Eric; Shah, Ronak; Goodenow, Debra A.; Myers, Jerry G., Jr.

    2015-01-01

    The Integrated Medical Model (IMM) is a probabilistic model that uses simulation to predict mission medical risk. Given a specific mission and crew scenario, medical events are simulated using Monte Carlo methodology to provide estimates of resource utilization, probability of evacuation, probability of loss of crew, and the amount of mission time lost due to illness. Mission and crew scenarios are defined by mission length, extravehicular activity (EVA) schedule, and crew characteristics including: sex, coronary artery calcium score, contacts, dental crowns, history of abdominal surgery, and EVA eligibility. The Integrated Medical Evidence Database (iMED) houses the model inputs for one hundred medical conditions using in-flight, analog, and terrestrial medical data. Inputs include incidence, event durations, resource utilization, and crew functional impairment. Severity of conditions is addressed by defining statistical distributions on the dichotomized best and worst-case scenarios for each condition. The outcome distributions for conditions are bounded by the treatment extremes of the fully treated scenario in which all required resources are available and the untreated scenario in which no required resources are available. Upon occurrence of a simulated medical event, treatment availability is assessed, and outcomes are generated depending on the status of the affected crewmember at the time of onset, including any pre-existing functional impairments or ongoing treatment of concurrent conditions. The main IMM outcomes, including probability of evacuation and loss of crew life, time lost due to medical events, and resource utilization, are useful in informing mission planning decisions. To date, the IMM has been used to assess mission-specific risks with and without certain crewmember characteristics, to determine the impact of eliminating certain resources from the mission medical kit, and to design medical kits that maximally benefit crew health while meeting

  3. The Integrated Medical Model: A Probabilistic Simulation Model for Predicting In-Flight Medical Risks

    NASA Technical Reports Server (NTRS)

    Keenan, Alexandra; Young, Millennia; Saile, Lynn; Boley, Lynn; Walton, Marlei; Kerstman, Eric; Shah, Ronak; Goodenow, Debra A.; Myers, Jerry G.

    2015-01-01

    The Integrated Medical Model (IMM) is a probabilistic model that uses simulation to predict mission medical risk. Given a specific mission and crew scenario, medical events are simulated using Monte Carlo methodology to provide estimates of resource utilization, probability of evacuation, probability of loss of crew, and the amount of mission time lost due to illness. Mission and crew scenarios are defined by mission length, extravehicular activity (EVA) schedule, and crew characteristics including: sex, coronary artery calcium score, contacts, dental crowns, history of abdominal surgery, and EVA eligibility. The Integrated Medical Evidence Database (iMED) houses the model inputs for one hundred medical conditions using in-flight, analog, and terrestrial medical data. Inputs include incidence, event durations, resource utilization, and crew functional impairment. Severity of conditions is addressed by defining statistical distributions on the dichotomized best and worst-case scenarios for each condition. The outcome distributions for conditions are bounded by the treatment extremes of the fully treated scenario in which all required resources are available and the untreated scenario in which no required resources are available. Upon occurrence of a simulated medical event, treatment availability is assessed, and outcomes are generated depending on the status of the affected crewmember at the time of onset, including any pre-existing functional impairments or ongoing treatment of concurrent conditions. The main IMM outcomes, including probability of evacuation and loss of crew life, time lost due to medical events, and resource utilization, are useful in informing mission planning decisions. To date, the IMM has been used to assess mission-specific risks with and without certain crewmember characteristics, to determine the impact of eliminating certain resources from the mission medical kit, and to design medical kits that maximally benefit crew health while meeting

  4. The medical model versus the just deserts model.

    PubMed

    Wolfgang, M E

    1988-01-01

    This paper traces the history of two models that have been influential in shaping modern views toward criminals. One of these two--the medical model--is based on the concept of rehabilitation, that is, treatment predicated on the attributes of the offender. The second of these two--the just deserts model--centers on retribution, that is, punishment deserved for the seriousness of the crime. Each model has been dominant in various periods of history. PMID:3395697

  5. [A research on healthcare integrating model of medical information system].

    PubMed

    Lü, Xudong; Duan, Huilong

    2005-02-01

    System integration is inevitable since there are lots of heterogeneous medical information systems in the complicated medical environment. The current medical communication standards often focus on one aspect of the integration and do not provide a general scheme. Based on the analysis of the application of medical integration, the medical integration model HIM (Healthcare integrating model) is put forward, and the dataflow integration framework, function integration framework and interface integration framework in the HIM are designed subsequently. HIM provides a 3-D scheme for the integration of medical information systems, which not only contains the three aspects of integration application vertically, but covers the whole medical area horizontally. PMID:15762128

  6. Integrated Medical Model Verification, Validation, and Credibility

    NASA Technical Reports Server (NTRS)

    Walton, Marlei; Kerstman, Eric; Foy, Millennia; Shah, Ronak; Saile, Lynn; Boley, Lynn; Butler, Doug; Myers, Jerry

    2014-01-01

    The Integrated Medical Model (IMM) was designed to forecast relative changes for a specified set of crew health and mission success risk metrics by using a probabilistic (stochastic process) model based on historical data, cohort data, and subject matter expert opinion. A probabilistic approach is taken since exact (deterministic) results would not appropriately reflect the uncertainty in the IMM inputs. Once the IMM was conceptualized, a plan was needed to rigorously assess input information, framework and code, and output results of the IMM, and ensure that end user requests and requirements were considered during all stages of model development and implementation. METHODS: In 2008, the IMM team developed a comprehensive verification and validation (VV) plan, which specified internal and external review criteria encompassing 1) verification of data and IMM structure to ensure proper implementation of the IMM, 2) several validation techniques to confirm that the simulation capability of the IMM appropriately represents occurrences and consequences of medical conditions during space missions, and 3) credibility processes to develop user confidence in the information derived from the IMM. When the NASA-STD-7009 (7009) was published, the IMM team updated their verification, validation, and credibility (VVC) project plan to meet 7009 requirements and include 7009 tools in reporting VVC status of the IMM. RESULTS: IMM VVC updates are compiled recurrently and include 7009 Compliance and Credibility matrices, IMM VV Plan status, and a synopsis of any changes or updates to the IMM during the reporting period. Reporting tools have evolved over the lifetime of the IMM project to better communicate VVC status. This has included refining original 7009 methodology with augmentation from the NASA-STD-7009 Guidance Document. End user requests and requirements are being satisfied as evidenced by ISS Program acceptance of IMM risk forecasts, transition to an operational model and

  7. The Integrated Medical Model: A Risk Assessment and Decision Support Tool for Space Flight Medical Systems

    NASA Technical Reports Server (NTRS)

    Kerstman, Eric; Minard, Charles; Saile, Lynn; deCarvalho, Mary Freire; Myers, Jerry; Walton, Marlei; Butler, Douglas; Iyengar, Sriram; Johnson-Throop, Kathy; Baumann, David

    2009-01-01

    The Integrated Medical Model (IMM) is a decision support tool that is useful to mission planners and medical system designers in assessing risks and designing medical systems for space flight missions. The IMM provides an evidence based approach for optimizing medical resources and minimizing risks within space flight operational constraints. The mathematical relationships among mission and crew profiles, medical condition incidence data, in-flight medical resources, potential crew functional impairments, and clinical end-states are established to determine probable mission outcomes. Stochastic computational methods are used to forecast probability distributions of crew health and medical resource utilization, as well as estimates of medical evacuation and loss of crew life. The IMM has been used in support of the International Space Station (ISS) medical kit redesign, the medical component of the ISS Probabilistic Risk Assessment, and the development of the Constellation Medical Conditions List. The IMM also will be used to refine medical requirements for the Constellation program. The IMM outputs for ISS and Constellation design reference missions will be presented to demonstrate the potential of the IMM in assessing risks, planning missions, and designing medical systems. The implementation of the IMM verification and validation plan will be reviewed. Additional planned capabilities of the IMM, including optimization techniques and the inclusion of a mission timeline, will be discussed. Given the space flight constraints of mass, volume, and crew medical training, the IMM is a valuable risk assessment and decision support tool for medical system design and mission planning.

  8. Model attraction in medical image object recognition

    NASA Astrophysics Data System (ADS)

    Tascini, Guido; Zingaretti, Primo

    1995-04-01

    This paper presents as new approach to image recognition based on a general attraction principle. A cognitive recognition is governed by a 'focus on attention' process that concentrates on the visual data subset of task- relevant type only. Our model-based approach combines it with another process, focus on attraction, which concentrates on the transformations of visual data having relevance for the matching. The recognition process is characterized by an intentional evolution of the visual data. This chain of image transformations is viewed as driven by an attraction field that attempts to reduce the distance between the image-point and the model-point in the feature space. The field sources are determined during a learning phase, by supplying the system with a training set. The paper describes a medical interpretation case in the feature space, concerning human skin lesions. The samples of the training set, supplied by the dermatologists, allow the system to learn models of lesions in terms of features such as hue factor, asymmetry factor, and asperity factor. The comparison of the visual data with the model derives the trend of image transformations, allowing a better definition of the given image and its classification. The algorithms are implemented in C language on a PC equipped with Matrox Image Series IM-1280 acquisition and processing boards. The work is now in progress.

  9. A Flexible Model for Correlated Medical Costs, with Application to Medical Expenditure Panel Survey Data

    PubMed Central

    Chen, Jinsong; Liu, Lei; Shih, Ya-Chen T.; Zhang, Daowen; Severini, Thomas A.

    2016-01-01

    We propose a flexible model for correlated medical cost data with several appealing features. First, the mean function is partially linear. Second, the distributional form for the response is not specified. Third, the covariance structure of correlated medical costs has a semiparametric form. We use extended generalized estimating equations to simultaneously estimate all parameters of interest. B-splines is used to estimate unknown functions, and a modification to Akaike Information Criterion is proposed for selecting knots in spline bases. We apply the model to correlated medical costs in the Medical Expenditure Panel Survey (MEPS) dataset. Simulation studies are conducted to assess the performance of our method. PMID:26403805

  10. A flexible model for correlated medical costs, with application to medical expenditure panel survey data.

    PubMed

    Chen, Jinsong; Liu, Lei; Shih, Ya-Chen T; Zhang, Daowen; Severini, Thomas A

    2016-03-15

    We propose a flexible model for correlated medical cost data with several appealing features. First, the mean function is partially linear. Second, the distributional form for the response is not specified. Third, the covariance structure of correlated medical costs has a semiparametric form. We use extended generalized estimating equations to simultaneously estimate all parameters of interest. B-splines are used to estimate unknown functions, and a modification to Akaike information criterion is proposed for selecting knots in spline bases. We apply the model to correlated medical costs in the Medical Expenditure Panel Survey dataset. Simulation studies are conducted to assess the performance of our method. PMID:26403805

  11. Development of a career coaching model for medical students

    PubMed Central

    Hur, Yera

    2016-01-01

    Purpose: Deciding on a future career path or choosing a career specialty is an important academic decision for medical students. The purpose of this study is to develop a career coaching model for medical students. Methods: This research was carried out in three steps. The first step was systematic review of previous studies. The second step was a need assessment of medical students. The third step was a career coaching model using the results acquired from the researched literature and the survey. Results: The career coaching stages were defined as three big phases: The career coaching stages were defined as the “crystallization” period (Pre-medical year 1 and 2), “specification” period (medical year 1 and 2), and “implementation” period (medical year 3 and 4). Conclusion: The career coaching model for medical students can be used in programming career coaching contents and also in identifying the outcomes of career coaching programs at an institutional level. PMID:26867586

  12. A Model for Enhancing Internet Medical Document Retrieval with “Medical Core Metadata”

    PubMed Central

    Malet, Gary; Munoz, Felix; Appleyard, Richard; Hersh, William

    1999-01-01

    Objective: Finding documents on the World Wide Web relevant to a specific medical information need can be difficult. The goal of this work is to define a set of document content description tags, or metadata encodings, that can be used to promote disciplined search access to Internet medical documents. Design: The authors based their approach on a proposed metadata standard, the Dublin Core Metadata Element Set, which has recently been submitted to the Internet Engineering Task Force. Their model also incorporates the National Library of Medicine's Medical Subject Headings (MeSH) vocabulary and Medline-type content descriptions. Results: The model defines a medical core metadata set that can be used to describe the metadata for a wide variety of Internet documents. Conclusions: The authors propose that their medical core metadata set be used to assign metadata to medical documents to facilitate document retrieval by Internet search engines. PMID:10094069

  13. Protalign: a 3-dimensional protein alignment assessment tool.

    PubMed

    Meads, D; Hansen, M D; Pang, A

    1999-01-01

    Protein fold recognition (sometimes called threading) is the prediction of a protein's 3-dimensional shape based on its similarity to a protein of known structure. Fold predictions are low resolution; that is, no effort is made to rotate the protein's component amino acid side chains into their correct spatial orientations. The goal is simply to recognize the protein family member that most closely resembles the target sequence of unknown structure and to create a sensible alignment of the target to the known structure (i.e., a structure-sequence alignment). To facilitate this type of structure prediction, we have designed a low resolution molecular graphics tool. ProtAlign introduces the ability to interact with and edit alignments directly in the 3-dimensional structure as well as in the usual 2-dimensional layout. It also contains several functions and features to help the user assess areas within the alignment. ProtAlign implements an open pipe architecture to allow other programs to access its molecular graphics capabilities. In addition, it is capable of "driving" other programs. Because amino acid side chain orientation is not relevant in fold recognition, we represent amino acid residues as abstract shapes or glyphs much like Lego (tm) blocks and we borrow techniques from comparative flow visualization using streamlines to provide clean depictions of the entire protein model. By creating a low resolution representation of protein structure, we are able to at least double the amount of information on the screen. At the same time, we create a view that is not as busy as the corresponding representations using traditional high resolution visualization methods which show detailed atomic structure. This eliminates distracting and possibly misleading visual clutter resulting from the mapping of protein alignment information onto a high resolution display of the known structure. This molecular graphics program is implemented in Open GL to facilitate porting to

  14. A model for selecting assessment methods for evaluating medical students in African medical schools.

    PubMed

    Walubo, Andrew; Burch, Vanessa; Parmar, Paresh; Raidoo, Deshandra; Cassimjee, Mariam; Onia, Rudy; Ofei, Francis

    2003-09-01

    Introduction of more effective and standardized assessment methods for testing students' performance in Africa's medical institutions has been hampered by severe financial and personnel shortages. Nevertheless, some African institutions have recognized the problem and are now revising their medical curricula, and, therefore, their assessment methods. These institutions, and those yet to come, need guidance on selecting assessment methods so as to adopt models that can be sustained locally. The authors provide a model for selecting assessment methods for testing medical students' performance in African medical institutions. The model systematically evaluates factors that influence implementation of an assessment method. Six commonly used methods (the essay examinations, short-answer questions, multiple-choice questions, patient-based clinical examination, problem-based oral examination [POE], and objective structured clinical examination) are evaluated by scoring and weighting against performance, cost, suitability, and safety factors. In the model, the highest score identifies the most appropriate method. Selection of an assessment method is illustrated using two institutional models, one depicting an ideal situation in which the objective structured clinical examination was preferred, and a second depicting the typical African scenario in which the essay and short-answer-question examinations were best. The POE method received the highest score and could be recommended as the most appropriate for Africa's medical institutions, but POE assessments require changing the medical curricula to a problem-based learning approach. The authors' model is easy to understand and promotes change in the medical curriculum and method of student assessment. PMID:14507620

  15. Improving Perceptual Skills with 3-Dimensional Animations.

    ERIC Educational Resources Information Center

    Johns, Janet Faye; Brander, Julianne Marie

    1998-01-01

    Describes three-dimensional computer aided design (CAD) models for every component in a representative mechanical system; the CAD models made it easy to generate 3-D animations that are ideal for teaching perceptual skills in multimedia computer-based technical training. Fifteen illustrations are provided. (AEF)

  16. Development of a change model for a controlled medical vocabulary.

    PubMed Central

    Oliver, D. E.; Shahar, Y.

    1997-01-01

    Managing change in controlled medical vocabularies is labor intensive and costly, but change is inevitable if vocabularies are to be kept up to date. The changes that are appropriate for a controlled medical vocabulary depend on the data stored for that vocabulary, and those data in turn depend on the needs of users. The set of change operations is the change model; the data stored about concepts comprise the concept model. Because the change model depends directly on the concept model, a discussion of the former necessitates a discussion of the latter. In this paper, we first present a set of tasks that we believe controlled medical vocabularies should handle. Next, we describe our concept model for a controlled medical vocabulary. Then, we review the literature on changes in existing vocabulary systems. Finally, we present our change model. We call our system, which incorporates the concept model and change model, the General Online Dictionary of Medicine (GOLDMINE). PMID:9357697

  17. 3DIVS: 3-Dimensional Immersive Virtual Sculpting

    SciTech Connect

    Kuester, F; Duchaineau, M A; Hamann, B; Joy, K I; Uva, A E

    2001-10-03

    Virtual Environments (VEs) have the potential to revolutionize traditional product design by enabling the transition from conventional CAD to fully digital product development. The presented prototype system targets closing the ''digital gap'' as introduced by the need for physical models such as clay models or mockups in the traditional product design and evaluation cycle. We describe a design environment that provides an intuitive human-machine interface for the creation and manipulation of three-dimensional (3D) models in a semi-immersive design space, focusing on ease of use and increased productivity for both designer and CAD engineers.

  18. Application of word-formation models in medical terms fixation.

    PubMed

    Bujalkova, M; Jureckova, A

    2003-01-01

    In their article the authors present goals of Latin teaching at medical faculties in Slovakia. They analyze in more details word-formation and structure of one-word medical terms from the point of view of their model teaching/learning and fixation. Presentation of the medical terms in models proved to be very effective for adult learners because they provide exact and easy-to-memorize scheme mechanisms that can be analogically applied in the production/manipulation and fixation of a whole range of medical terms. In conclusion several examples--excercises are presented to illustrate their use in teaching practice. (Fig. 1, Ref. 7.). PMID:15055735

  19. Portal of medical data models: information infrastructure for medical research and healthcare

    PubMed Central

    Dugas, Martin; Neuhaus, Philipp; Meidt, Alexandra; Doods, Justin; Storck, Michael; Bruland, Philipp; Varghese, Julian

    2016-01-01

    Introduction: Information systems are a key success factor for medical research and healthcare. Currently, most of these systems apply heterogeneous and proprietary data models, which impede data exchange and integrated data analysis for scientific purposes. Due to the complexity of medical terminology, the overall number of medical data models is very high. At present, the vast majority of these models are not available to the scientific community. The objective of the Portal of Medical Data Models (MDM, https://medical-data-models.org) is to foster sharing of medical data models. Methods: MDM is a registered European information infrastructure. It provides a multilingual platform for exchange and discussion of data models in medicine, both for medical research and healthcare. The system is developed in collaboration with the University Library of Münster to ensure sustainability. A web front-end enables users to search, view, download and discuss data models. Eleven different export formats are available (ODM, PDF, CDA, CSV, MACRO-XML, REDCap, SQL, SPSS, ADL, R, XLSX). MDM contents were analysed with descriptive statistics. Results: MDM contains 4387 current versions of data models (in total 10 963 versions). 2475 of these models belong to oncology trials. The most common keyword (n = 3826) is ‘Clinical Trial’; most frequent diseases are breast cancer, leukemia, lung and colorectal neoplasms. Most common languages of data elements are English (n = 328 557) and German (n = 68 738). Semantic annotations (UMLS codes) are available for 108 412 data items, 2453 item groups and 35 361 code list items. Overall 335 087 UMLS codes are assigned with 21 847 unique codes. Few UMLS codes are used several thousand times, but there is a long tail of rarely used codes in the frequency distribution. Discussion: Expected benefits of the MDM portal are improved and accelerated design of medical data models by sharing best practice, more standardised data models

  20. The medical director in integrated clinical care models.

    PubMed

    Parker, Thomas F; Aronoff, George R

    2015-07-01

    Integrated clinical care models, like Accountable Care Organizations and ESRD Seamless Care Organizations, present new opportunities for dialysis facility medical directors to affect changes in care that result in improved patient outcomes. Currently, there is little scholarly information on what role the medical director should play. In this opinion-based review, it is predicted that dialysis providers, the hospitals in which the medical director and staff physicians practice, and the payers with which they contract are going to insist that, as care becomes more integrated, dialysis facility medical directors participate in new ways to improve quality and decrease the costs of care. Six broad areas are proposed where dialysis unit medical directors can have the greatest effect on shifting the quality-care paradigm where integrated care models are used. The medical director will need to develop an awareness of the regional medical care delivery system, collect and analyze actionable data, determine patient outcomes to be targeted that are mutually agreed on by participating physicians and institutions, develop processes of care that result in improved patient outcomes, and lead and inform the medical staff. Three practical examples of patient-centered, quality-focused programs developed and implemented by dialysis unit medical directors and their practice partners that targeted dialysis access, modality choice, and fluid volume management are presented. Medical directors are encouraged to move beyond traditional roles and embrace responsibilities associated with integrated care. PMID:25352380

  1. 3-dimensional strain fields from tomographic measurements

    NASA Astrophysics Data System (ADS)

    Haldrup, K.; Nielsen, S. F.; Mishnaevsky, L., Jr.; Beckmann, F.; Wert, J. A.

    2006-08-01

    Understanding the distributions of strain within solid bodies undergoing plastic deformations has been of interest for many years in a wide range of disciplines, ranging from basic materials science to biology. However, the desire to investigate these strain fields has been frustrated by the inaccessibility of the interior of most samples to detailed investigation without destroying the sample in the process. To some extent, this has been remedied by the development of advanced surface measurement techniques as well as computer models based on Finite Element methods. Over the last decade, this situation has changed by the introduction of a range of tomographic methods based both on advances in computer technology and in instrumentation, advances which have opened up the interior of optically opaque samples for detailed investigations. We present a general method for assessing the strain in the interior of marker-containing specimens undergoing various types of deformation. The results are compared with Finite Element modelling.

  2. A rotational stereoscopic 3-dimensional movement aftereffect.

    PubMed

    Webster, W R; Panthradil, J T; Conway, D M

    1998-06-01

    A stereoscopic rotational movement aftereffect (MAE) and a stereoscopic bi-directional MAE were generated by rotation of a cyclopean random dot cylinder in depth and by movement of two cyclopean random dot planes in opposite directions, respectively. Cross-adaptational MAEs were also generated on each other, but not with stimuli lacking any disparity. Cross-adaptation MAEs were generated between stereoscopic and non-stereoscopic random dot stimuli moving in the one X/Y plane. Spontaneous reversals in direction of movement were observed with bistable stimuli lacking disparity. Two models of the middle temporal area were considered which might explain both the stereoscopic MAEs and the spontaneous reversals. PMID:9797953

  3. Predicting Medical Specialty Choice: A Model Based on Students' Records.

    ERIC Educational Resources Information Center

    Fadem, Barbara H.; And Others

    1984-01-01

    A discriminant analysis of objective and subjective measures from the records of students who graduated from the University of Medicine and Dentistry of New Jersey-New Jersey Medical School over a six-year period was used to generate a model for the prediction of medical specialty choice. (Author/MLW)

  4. Medical Specialty Decision Model: Utilizing Social Cognitive Career Theory

    ERIC Educational Resources Information Center

    Gibson, Denise D.; Borges, Nicole J.

    2004-01-01

    Objectives: The purpose of this study was to develop a working model to explain medical specialty decision-making. Using Social Cognitive Career Theory, we examined personality, medical specialty preferences, job satisfaction, and expectations about specialty choice to create a conceptual framework to guide specialty choice decision-making.…

  5. Four Models of Medical Education about Elder Mistreatment.

    ERIC Educational Resources Information Center

    Heath, John M.; Dyer, Carmel B.; Kerzner, Lawrence J.; Mosqueda, Laura; Murphy, Carole

    2002-01-01

    Describe four models of incorporating elder-mistreatment curriculum and collaboration with adult protective services into geriatrics medical education. Draws on efforts at the University of Medicine and Dentistry of New Jersey--Robert Wood Johnson Medical School; the University of California, Irvine College of Medicine; Hennepin County Medical…

  6. Expanded Medical Home Model Works for Children in Foster Care

    ERIC Educational Resources Information Center

    Jaudes, Paula Kienberger; Champagne, Vince; Harden, Allen; Masterson, James; Bilaver, Lucy A.

    2012-01-01

    The Illinois Child Welfare Department implemented a statewide health care system to ensure that children in foster care obtain quality health care by providing each child with a medical home. This study demonstrates that the Medical Home model works for children in foster care providing better health outcomes in higher immunization rates. These…

  7. A Medication Safety Model: A Case Study in Thai Hospital

    PubMed Central

    Rattanarojsakul, Phichai; Thawesaengskulthai, Natcha

    2013-01-01

    Reaching zero defects is vital in medication service. Medication error can be reduced if the causes are recognized. The purpose of this study is to search for a conceptual framework of the causes of medication error in Thailand and to examine relationship between these factors and its importance. The study was carried out upon an in-depth case study and survey of hospital personals who were involved in the drug use process. The structured survey was based on Emergency Care Research Institute (ECRI) (2008) questionnaires focusing on the important factors that affect the medication safety. Additional questionnaires included content to the context of Thailand's private hospital, validated by five-hospital qualified experts. By correlation Pearson analysis, the result revealed 14 important factors showing a linear relationship with drug administration error except the medication reconciliation. By independent sample t-test, the administration error in the hospital was significantly related to external impact. The multiple regression analysis of the detail of medication administration also indicated the patient identification before administration of medication, detection of the risk of medication adverse effects and assurance of medication administration at the right time, dosage and route were statistically significant at 0.05 level. The major implication of the study is to propose a medication safety model in a Thai private hospital. PMID:23985110

  8. A Seafloor Benchmark for 3-dimensional Geodesy

    NASA Astrophysics Data System (ADS)

    Chadwell, C. D.; Webb, S. C.; Nooner, S. L.

    2014-12-01

    We have developed an inexpensive, permanent seafloor benchmark to increase the longevity of seafloor geodetic measurements. The benchmark provides a physical tie to the sea floor lasting for decades (perhaps longer) on which geodetic sensors can be repeatedly placed and removed with millimeter resolution. Global coordinates estimated with seafloor geodetic techniques will remain attached to the benchmark allowing for the interchange of sensors as they fail or become obsolete, or for the sensors to be removed and used elsewhere, all the while maintaining a coherent series of positions referenced to the benchmark. The benchmark has been designed to free fall from the sea surface with transponders attached. The transponder can be recalled via an acoustic command sent from the surface to release from the benchmark and freely float to the sea surface for recovery. The duration of the sensor attachment to the benchmark will last from a few days to a few years depending on the specific needs of the experiment. The recovered sensors are then available to be reused at other locations, or again at the same site in the future. Three pins on the sensor frame mate precisely and unambiguously with three grooves on the benchmark. To reoccupy a benchmark a Remotely Operated Vehicle (ROV) uses its manipulator arm to place the sensor pins into the benchmark grooves. In June 2014 we deployed four benchmarks offshore central Oregon. We used the ROV Jason to successfully demonstrate the removal and replacement of packages onto the benchmark. We will show the benchmark design and its operational capabilities. Presently models of megathrust slip within the Cascadia Subduction Zone (CSZ) are mostly constrained by the sub-aerial GPS vectors from the Plate Boundary Observatory, a part of Earthscope. More long-lived seafloor geodetic measures are needed to better understand the earthquake and tsunami risk associated with a large rupture of the thrust fault within the Cascadia subduction zone

  9. FMEA: a model for reducing medical errors.

    PubMed

    Chiozza, Maria Laura; Ponzetti, Clemente

    2009-06-01

    Patient safety is a management issue, in view of the fact that clinical risk management has become an important part of hospital management. Failure Mode and Effect Analysis (FMEA) is a proactive technique for error detection and reduction, firstly introduced within the aerospace industry in the 1960s. Early applications in the health care industry dating back to the 1990s included critical systems in the development and manufacture of drugs and in the prevention of medication errors in hospitals. In 2008, the Technical Committee of the International Organization for Standardization (ISO), licensed a technical specification for medical laboratories suggesting FMEA as a method for prospective risk analysis of high-risk processes. Here we describe the main steps of the FMEA process and review data available on the application of this technique to laboratory medicine. A significant reduction of the risk priority number (RPN) was obtained when applying FMEA to blood cross-matching, to clinical chemistry analytes, as well as to point-of-care testing (POCT). PMID:19298799

  10. A hypergraphic model of medical informatics: curriculum development guide.

    PubMed Central

    Chi, X.; Pavilcek, K.

    1999-01-01

    Medical informatics, as a descriptive, scientific study, must be mathematically or theoretically described. Is it important to define a model for medical informatics? The answer is worth pursuing. The medical informatics profession stands to benefit three-fold: first, by clarifying the vagueness of the definition of medical informatics, secondly, by identifying the scope and content for educational programs, and, thirdly, by defining career opportunities for its graduates. Existing medical informatics curricula are not comparable. Consequently, the knowledge and skills of graduates from these programs are difficult to assess. The challenge is to promote academics that develops graduates for prospective employers to fulfill the criteria of the health care industry and, simultaneously, compete with computer science programs that produce information technology graduates. In order to meet this challenge, medical informatics programs must have unique curricula that distinguishes its graduates. The solution is to educate students in a comparable manner across the domain of medical informatics. This paper discusses a theoretical model for medical informatics. Images Figure PMID:10566316

  11. Sleep Disruption Medical Intervention Forecasting (SDMIF) Module for the Integrated Medical Model

    NASA Technical Reports Server (NTRS)

    Lewandowski, Beth; Brooker, John; Mallis, Melissa; Hursh, Steve; Caldwell, Lynn; Myers, Jerry

    2011-01-01

    The NASA Integrated Medical Model (IMM) assesses the risk, including likelihood and impact of occurrence, of all credible in-flight medical conditions. Fatigue due to sleep disruption is a condition that could lead to operational errors, potentially resulting in loss of mission or crew. Pharmacological consumables are mitigation strategies used to manage the risks associated with sleep deficits. The likelihood of medical intervention due to sleep disruption was estimated with a well validated sleep model and a Monte Carlo computer simulation in an effort to optimize the quantity of consumables. METHODS: The key components of the model are the mission parameter program, the calculation of sleep intensity and the diagnosis and decision module. The mission parameter program was used to create simulated daily sleep/wake schedules for an ISS increment. The hypothetical schedules included critical events such as dockings and extravehicular activities and included actual sleep time and sleep quality. The schedules were used as inputs to the Sleep, Activity, Fatigue and Task Effectiveness (SAFTE) Model (IBR Inc., Baltimore MD), which calculated sleep intensity. Sleep data from an ISS study was used to relate calculated sleep intensity to the probability of sleep medication use, using a generalized linear model for binomial regression. A human yes/no decision process using a binomial random number was also factored into sleep medication use probability. RESULTS: These probability calculations were repeated 5000 times resulting in an estimate of the most likely amount of sleep aids used during an ISS mission and a 95% confidence interval. CONCLUSIONS: These results were transferred to the parent IMM for further weighting and integration with other medical conditions, to help inform operational decisions. This model is a potential planning tool for ensuring adequate sleep during sleep disrupted periods of a mission.

  12. Medical-concept models and medical records: an approach based on GALEN and PEN&PAD.

    PubMed Central

    Rector, A L; Glowinski, A J; Nowlan, W A; Rossi-Mori, A

    1995-01-01

    OBJECTIVES: To investigate the issues raised in applying a preliminary version of the GALEN compositional concept reference (CORE) model to a series of radiographic reports, and to demonstrate that the same underlying concept model could be used in conjunction with both a detailed, fine-grained model of medical records based on that used in the PEN&PAD project and with other more conventional medical-record models. DESIGN: Following analysis and representation of concepts from a set of reports, a single report was taken as a "case study." This report was analyzed in detail in its entirety and represented using each of the medical-record models. RESULTS: The reports were successfully represented within the limits of the study, but a number of significant issues were raised. CONCLUSION: The compositional approach plus the PEN&PAD medical-record model allowed detailed information in the radiographic report to be represented, including information about the inferences and the clinical process. The resulting representation was large, and more compact representations may be necessary for some systems. Alternative encapsulations of the information as might be used in such systems were successfully prepared. The compositional approach avoided many issues that often cause controversy in the design of traditional coding and classification systems, but it raised other issues, including the handling of ambiguity and underspecification, linkage to information not explicitly present in the report, and questions concerning the focus of individual concepts. All work is preliminary and definitive conclusions await further studies and systematic evaluation. PMID:7895133

  13. From 2-dimensional cephalograms to 3-dimensional computed tomography scans.

    PubMed

    Halazonetis, Demetrios J

    2005-05-01

    Computed tomography is entering the orthodontic specialty as a mainstream diagnostic modality. Radiation exposure and cost have decreased significantly, and the diagnostic value is very high compared with traditional radiographic options. However, 3-dimensional data present new challenges and need a different approach from traditional viewing of static images to make the most of the available possibilities. Advances in computer hardware and software now enable interactive display of the data on personal computers, with the ability to selectively view soft or hard tissues from any angle. Transfer functions are used to apply transparency and color. Cephalometric measurements can be taken by digitizing points in 3-dimensional coordinates. Application of 3-dimensional data is expected to increase significantly soon and might eventually replace many conventional orthodontic records that are in use today. PMID:15877045

  14. A model for sustainable short-term international medical trips.

    PubMed

    Suchdev, Parminder; Ahrens, Kym; Click, Eleanor; Macklin, Lori; Evangelista, Doris; Graham, Elinor

    2007-01-01

    The health status of many people in developing countries is often dismal compared with the norms in industrialized countries. Increasingly, medical practitioners in the United States and other industrialized countries have become interested in global health issues, an interest that often takes the form of short-term international medical trips. We discuss several ethical issues associated with participation in such trips and use our experiences in developing the Children's Health International Medical Project of Seattle (CHIMPS) to outline and illustrate a set of 7 guiding principles for making these trips. CHIMPS is a resident-run, faculty-supported international medical program founded in 2002 by pediatric residents at the University of Washington in Seattle. Members of CHIMPS work with a rural community in El Salvador to support ongoing public health interventions there and provide sustainable medical care in collaboration with the community and a local nongovernmental organization. The 7 principles developed as a result of this work-mission, collaboration, education, service, teamwork, sustainability, and evaluation-can be used as a model for health practitioners as they develop or select international medical trips. The importance of partnering with the community and working within the existing medical and public health infrastructure is emphasized. Many of the challenges of doing international medical work can be overcome when efforts are guided by a few specific principles, such as those we have outlined. PMID:17660105

  15. Modeling Medical Ethics through Intelligent Agents

    NASA Astrophysics Data System (ADS)

    Machado, José; Miranda, Miguel; Abelha, António; Neves, José; Neves, João

    The amount of research using health information has increased dramatically over the last past years. Indeed, a significative number of healthcare institutions have extensive Electronic Health Records (EHR), collected over several years for clinical and teaching purposes, but are uncertain as to the proper circumstances in which to use them to improve the delivery of care to the ones in need. Research Ethics Boards in Portugal and elsewhere in the world are grappling with these issues, but lack clear guidance regarding their role in the creation of and access to EHRs. However, we feel we have an effective way to handle Medical Ethics if we look to the problem under a structured and more rational way. Indeed, we felt that physicians were not aware of the relevance of the subject in their pre-clinical years, but their interest increase when they were exposed to patients. On the other hand, once EHRs are stored in machines, we also felt that we had to find a way to ensure that the behavior of machines toward human users, and perhaps other machines as well, is ethically acceptable. Therefore, in this article we discuss the importance of machine ethics and the need for machines that represent ethical principles explicitly. It is also shown how a machine may abstract an ethical principle from a logical representation of ethical judgments and use that principle to guide its own behavior.

  16. Concepts for a model of good medical laboratory services.

    PubMed

    Haeckel, R; Böhm, M; Capel, P J; Høiby, N; Jansen, R T; Kallner, A; Kelly, A; Kruse-Jarres, J D; Küffer, H; Libeer, J C

    1998-06-01

    Several international standards and corresponding interpretation documents for quality management systems have been published. Although these standards are found useful to some extent, they are considered to be insufficient in several areas important for medical laboratories particularly in the pre- and post-examinational phases. The normative document for accreditation of laboratories (ISO/IEC Guide 25) is presently being revised and a document for medical laboratories (ISO/TC 212, CD 15189) is at draft stage. Both aim to include aspects of total quality management. The concept of total quality management is rather vague. Generally, its goal has been defined as "business excellence". This term, however, needs some explanation if applied to medical laboratories. Therefore, a project group of the European Confederation of Laboratory Medicine (ECLM) has developed a model for total quality management, which is based on a comprehensive management concept issued by the European Foundation for Quality Management. In the case of a medical laboratory, the term "business excellence" should be replaced by "good medical laboratory services". The proposed model could serve as a basis for future developments of total quality management standards in laboratory medicine. The goal of the "journey" should be clarified before it starts. To the best of our knowledge, this is the first attempt to develop a model of a good medical laboratory. PMID:9711429

  17. Medical Device Integration Model Based on the Internet of Things

    PubMed Central

    Hao, Aiyu; Wang, Ling

    2015-01-01

    At present, hospitals in our country have basically established the HIS system, which manages registration, treatment, and charge, among many others, of patients. During treatment, patients need to use medical devices repeatedly to acquire all sorts of inspection data. Currently, the output data of the medical devices are often manually input into information system, which is easy to get wrong or easy to cause mismatches between inspection reports and patients. For some small hospitals of which information construction is still relatively weak, the information generated by the devices is still presented in the form of paper reports. When doctors or patients want to have access to the data at a given time again, they can only look at the paper files. Data integration between medical devices has long been a difficult problem for the medical information system, because the data from medical devices are lack of mandatory unified global standards and have outstanding heterogeneity of devices. In order to protect their own interests, manufacturers use special protocols, etc., thus causing medical decices to still be the "lonely island" of hospital information system. Besides, unfocused application of the data will lead to failure to achieve a reasonable distribution of medical resources. With the deepening of IT construction in hospitals, medical information systems will be bound to develop towards mobile applications, intelligent analysis, and interconnection and interworking, on the premise that there is an effective medical device integration (MDI) technology. To this end, this paper presents a MDI model based on the Internet of Things (IoT). Through abstract classification, this model is able to extract the common characteristics of the devices, resolve the heterogeneous differences between them, and employ a unified protocol to integrate data between devices. And by the IoT technology, it realizes interconnection network of devices and conducts associate matching

  18. Medical Device Integration Model Based on the Internet of Things.

    PubMed

    Hao, Aiyu; Wang, Ling

    2015-01-01

    At present, hospitals in our country have basically established the HIS system, which manages registration, treatment, and charge, among many others, of patients. During treatment, patients need to use medical devices repeatedly to acquire all sorts of inspection data. Currently, the output data of the medical devices are often manually input into information system, which is easy to get wrong or easy to cause mismatches between inspection reports and patients. For some small hospitals of which information construction is still relatively weak, the information generated by the devices is still presented in the form of paper reports. When doctors or patients want to have access to the data at a given time again, they can only look at the paper files. Data integration between medical devices has long been a difficult problem for the medical information system, because the data from medical devices are lack of mandatory unified global standards and have outstanding heterogeneity of devices. In order to protect their own interests, manufacturers use special protocols, etc., thus causing medical decices to still be the "lonely island" of hospital information system. Besides, unfocused application of the data will lead to failure to achieve a reasonable distribution of medical resources. With the deepening of IT construction in hospitals, medical information systems will be bound to develop towards mobile applications, intelligent analysis, and interconnection and interworking, on the premise that there is an effective medical device integration (MDI) technology. To this end, this paper presents a MDI model based on the Internet of Things (IoT). Through abstract classification, this model is able to extract the common characteristics of the devices, resolve the heterogeneous differences between them, and employ a unified protocol to integrate data between devices. And by the IoT technology, it realizes interconnection network of devices and conducts associate matching

  19. Medical Updates Number 5 to the International Space Station Probability Risk Assessment (PRA) Model Using the Integrated Medical Model

    NASA Technical Reports Server (NTRS)

    Butler, Doug; Bauman, David; Johnson-Throop, Kathy

    2011-01-01

    The Integrated Medical Model (IMM) Project has been developing a probabilistic risk assessment tool, the IMM, to help evaluate in-flight crew health needs and impacts to the mission due to medical events. This package is a follow-up to a data package provided in June 2009. The IMM currently represents 83 medical conditions and associated ISS resources required to mitigate medical events. IMM end state forecasts relevant to the ISS PRA model include evacuation (EVAC) and loss of crew life (LOCL). The current version of the IMM provides the basis for the operational version of IMM expected in the January 2011 timeframe. The objectives of this data package are: 1. To provide a preliminary understanding of medical risk data used to update the ISS PRA Model. The IMM has had limited validation and an initial characterization of maturity has been completed using NASA STD 7009 Standard for Models and Simulation. The IMM has been internally validated by IMM personnel but has not been validated by an independent body external to the IMM Project. 2. To support a continued dialogue between the ISS PRA and IMM teams. To ensure accurate data interpretation, and that IMM output format and content meets the needs of the ISS Risk Management Office and ISS PRA Model, periodic discussions are anticipated between the risk teams. 3. To help assess the differences between the current ISS PRA and IMM medical risk forecasts of EVAC and LOCL. Follow-on activities are anticipated based on the differences between the current ISS PRA medical risk data and the latest medical risk data produced by IMM.

  20. Revisiting "Discrepancy Analysis in Continuing Medical Education: A Conceptual Model"

    ERIC Educational Resources Information Center

    Fox, Robert D.

    2011-01-01

    Based upon a review and analysis of selected literature, the author presents a conceptual model of discrepancy analysis evaluation for planning, implementing, and assessing the impact of continuing medical education (CME). The model is described in terms of its value as a means of diagnosing errors in the development and implementation of CME. The…

  1. The 3-dimensional construction of the Rae craton, central Canada

    NASA Astrophysics Data System (ADS)

    Snyder, David B.; Craven, James A.; Pilkington, Mark; Hillier, Michael J.

    2015-10-01

    Reconstruction of the 3-dimensional tectonic assembly of early continents, first as Archean cratons and then Proterozoic shields, remains poorly understood. In this paper, all readily available geophysical and geochemical data are assembled in a 3-D model with the most accurate bedrock geology in order to understand better the geometry of major structures within the Rae craton of central Canada. Analysis of geophysical observations of gravity and seismic wave speed variations revealed several lithospheric-scale discontinuities in physical properties. Where these discontinuities project upward to correlate with mapped upper crustal geological structures, the discontinuities can be interpreted as shear zones. Radiometric dating of xenoliths provides estimates of rock types and ages at depth beneath sparse kimberlite occurrences. These ages can also be correlated to surface rocks. The 3.6-2.6 Ga Rae craton comprises at least three smaller continental terranes, which "cratonized" during a granitic bloom. Cratonization probably represents final differentiation of early crust into a relatively homogeneous, uniformly thin (35-42 km), tonalite-trondhjemite-granodiorite crust with pyroxenite layers near the Moho. The peak thermotectonic event at 1.86-1.7 Ga was associated with the Hudsonian orogeny that assembled several cratons and lesser continental blocks into the Canadian Shield using a number of southeast-dipping megathrusts. This orogeny metasomatized, mineralized, and recrystallized mantle and lower crustal rocks, apparently making them more conductive by introducing or concentrating sulfides or graphite. Little evidence exists of thin slabs similar to modern oceanic lithosphere in this Precambrian construction history whereas underthrusting and wedging of continental lithosphere is inferred from multiple dipping discontinuities.

  2. A 3-Dimensional Anatomic Study of the Distal Biceps Tendon

    PubMed Central

    Walton, Christine; Li, Zhi; Pennings, Amanda; Agur, Anne; Elmaraghy, Amr

    2015-01-01

    Background Complete rupture of the distal biceps tendon from its osseous attachment is most often treated with operative intervention. Knowledge of the overall tendon morphology as well as the orientation of the collagenous fibers throughout the musculotendinous junction are key to intraoperative decision making and surgical technique in both the acute and chronic setting. Unfortunately, there is little information available in the literature. Purpose To comprehensively describe the morphology of the distal biceps tendon. Study Design Descriptive laboratory study. Methods The distal biceps terminal musculature, musculotendinous junction, and tendon were digitized in 10 cadaveric specimens and data reconstructed using 3-dimensional modeling. Results The average length, width, and thickness of the external distal biceps tendon were found to be 63.0, 6.0, and 3.0 mm, respectively. A unique expansion of the tendon fibers within the distal muscle was characterized, creating a thick collagenous network along the central component between the long and short heads. Conclusion This study documents the morphologic parameters of the native distal biceps tendon. Reconstruction may be necessary, especially in chronic distal biceps tendon ruptures, if the remaining tendon morphology is significantly compromised compared with the native distal biceps tendon. Knowledge of normal anatomical distal biceps tendon parameters may also guide the selection of a substitute graft with similar morphological characteristics. Clinical Relevance A thorough description of distal biceps tendon morphology is important to guide intraoperative decision making between primary repair and reconstruction and to better select the most appropriate graft. The detailed description of the tendinous expansion into the muscle may provide insight into better graft-weaving and suture-grasping techniques to maximize proximal graft incorporation. PMID:26665092

  3. Differential Cross Section Kinematics for 3-dimensional Transport Codes

    NASA Technical Reports Server (NTRS)

    Norbury, John W.; Dick, Frank

    2008-01-01

    In support of the development of 3-dimensional transport codes, this paper derives the relevant relativistic particle kinematic theory. Formulas are given for invariant, spectral and angular distributions in both the lab (spacecraft) and center of momentum frames, for collisions involving 2, 3 and n - body final states.

  4. Controlled teleportation of a 3-dimensional bipartite quantum state

    NASA Astrophysics Data System (ADS)

    Cao, Hai-Jing; Chen, Zhong-Hua; Song, He-Shan

    2008-07-01

    A controlled teleportation scheme of an unknown 3-dimensional (3D) two-particle quantum state is proposed, where a 3D Bell state and 3D GHZ state function as the quantum channel. This teleportation scheme can be directly generalized to teleport an unknown d-dimensional bipartite quantum state.

  5. Model selection and inference for censored lifetime medical expenditures.

    PubMed

    Johnson, Brent A; Long, Qi; Huang, Yijian; Chansky, Kari; Redman, Mary

    2016-09-01

    Identifying factors associated with increased medical cost is important for many micro- and macro-institutions, including the national economy and public health, insurers and the insured. However, assembling comprehensive national databases that include both the cost and individual-level predictors can prove challenging. Alternatively, one can use data from smaller studies with the understanding that conclusions drawn from such analyses may be limited to the participant population. At the same time, smaller clinical studies have limited follow-up and lifetime medical cost may not be fully observed for all study participants. In this context, we develop new model selection methods and inference procedures for secondary analyses of clinical trial data when lifetime medical cost is subject to induced censoring. Our model selection methods extend a theory of penalized estimating function to a calibration regression estimator tailored for this data type. Next, we develop a novel inference procedure for the unpenalized regression estimator using perturbation and resampling theory. Then, we extend this resampling plan to accommodate regularized coefficient estimation of censored lifetime medical cost and develop postselection inference procedures for the final model. Our methods are motivated by data from Southwest Oncology Group Protocol 9509, a clinical trial of patients with advanced nonsmall cell lung cancer, and our models of lifetime medical cost are specific to this population. But the methods presented in this article are built on rather general techniques and could be applied to larger databases as those data become available. PMID:26689300

  6. Dialect Topic Modeling for Improved Consumer Medical Search

    SciTech Connect

    Crain, Steven P.; Yang, Shuang-Hong; Zha, Hongyuan; Jiao, Yu

    2010-01-01

    Access to health information by consumers is ham- pered by a fundamental language gap. Current attempts to close the gap leverage consumer oriented health information, which does not, however, have good coverage of slang medical terminology. In this paper, we present a Bayesian model to automatically align documents with different dialects (slang, com- mon and technical) while extracting their semantic topics. The proposed diaTM model enables effective information retrieval, even when the query contains slang words, by explicitly modeling the mixtures of dialects in documents and the joint influence of dialects and topics on word selection. Simulations us- ing consumer questions to retrieve medical information from a corpus of medical documents show that diaTM achieves a 25% improvement in information retrieval relevance by nDCG@5 over an LDA baseline.

  7. A critical evaluation of secondary cancer risk models applied to Monte Carlo dose distributions of 2-dimensional, 3-dimensional conformal and hybrid intensity-modulated radiation therapy for breast cancer.

    PubMed

    Joosten, A; Bochud, F; Moeckli, R

    2014-08-21

    The comparison of radiotherapy techniques regarding secondary cancer risk has yielded contradictory results possibly stemming from the many different approaches used to estimate risk. The purpose of this study was to make a comprehensive evaluation of different available risk models applied to detailed whole-body dose distributions computed by Monte Carlo for various breast radiotherapy techniques including conventional open tangents, 3D conformal wedged tangents and hybrid intensity modulated radiation therapy (IMRT). First, organ-specific linear risk models developed by the International Commission on Radiological Protection (ICRP) and the Biological Effects of Ionizing Radiation (BEIR) VII committee were applied to mean doses for remote organs only and all solid organs. Then, different general non-linear risk models were applied to the whole body dose distribution. Finally, organ-specific non-linear risk models for the lung and breast were used to assess the secondary cancer risk for these two specific organs. A total of 32 different calculated absolute risks resulted in a broad range of values (between 0.1% and 48.5%) underlying the large uncertainties in absolute risk calculation. The ratio of risk between two techniques has often been proposed as a more robust assessment of risk than the absolute risk. We found that the ratio of risk between two techniques could also vary substantially considering the different approaches to risk estimation. Sometimes the ratio of risk between two techniques would range between values smaller and larger than one, which then translates into inconsistent results on the potential higher risk of one technique compared to another. We found however that the hybrid IMRT technique resulted in a systematic reduction of risk compared to the other techniques investigated even though the magnitude of this reduction varied substantially with the different approaches investigated. Based on the epidemiological data available, a reasonable

  8. A critical evaluation of secondary cancer risk models applied to Monte Carlo dose distributions of 2-dimensional, 3-dimensional conformal and hybrid intensity-modulated radiation therapy for breast cancer

    NASA Astrophysics Data System (ADS)

    Joosten, A.; Bochud, F.; Moeckli, R.

    2014-08-01

    The comparison of radiotherapy techniques regarding secondary cancer risk has yielded contradictory results possibly stemming from the many different approaches used to estimate risk. The purpose of this study was to make a comprehensive evaluation of different available risk models applied to detailed whole-body dose distributions computed by Monte Carlo for various breast radiotherapy techniques including conventional open tangents, 3D conformal wedged tangents and hybrid intensity modulated radiation therapy (IMRT). First, organ-specific linear risk models developed by the International Commission on Radiological Protection (ICRP) and the Biological Effects of Ionizing Radiation (BEIR) VII committee were applied to mean doses for remote organs only and all solid organs. Then, different general non-linear risk models were applied to the whole body dose distribution. Finally, organ-specific non-linear risk models for the lung and breast were used to assess the secondary cancer risk for these two specific organs. A total of 32 different calculated absolute risks resulted in a broad range of values (between 0.1% and 48.5%) underlying the large uncertainties in absolute risk calculation. The ratio of risk between two techniques has often been proposed as a more robust assessment of risk than the absolute risk. We found that the ratio of risk between two techniques could also vary substantially considering the different approaches to risk estimation. Sometimes the ratio of risk between two techniques would range between values smaller and larger than one, which then translates into inconsistent results on the potential higher risk of one technique compared to another. We found however that the hybrid IMRT technique resulted in a systematic reduction of risk compared to the other techniques investigated even though the magnitude of this reduction varied substantially with the different approaches investigated. Based on the epidemiological data available, a reasonable

  9. Model-based engineering for medical-device software.

    PubMed

    Ray, Arnab; Jetley, Raoul; Jones, Paul L; Zhang, Yi

    2010-01-01

    This paper demonstrates the benefits of adopting model-based design techniques for engineering medical device software. By using a patient-controlled analgesic (PCA) infusion pump as a candidate medical device, the authors show how using models to capture design information allows for i) fast and efficient construction of executable device prototypes ii) creation of a standard, reusable baseline software architecture for a particular device family, iii) formal verification of the design against safety requirements, and iv) creation of a safety framework that reduces verification costs for future versions of the device software. 1. PMID:21142522

  10. A 3-dimensional Analysis of the Cassiopeia A Supernova Remnant

    NASA Astrophysics Data System (ADS)

    Isensee, Karl

    We present a multi-wavelength study of the nearby supernova remnant Cassiopeia A (Cas A). Easily resolvable supernova remnants such as Cas A provide a unique opportunity to test supernova explosion models. Additionally, we can observe key processes in the interstellar medium as the ejecta from the initial explosion encounter Cas A's powerful shocks. In order to accomplish these science goals, we used the Spitzer Space Telescope's Infrared Spectrograph to create a high resolution spectral map of select regions of Cas A, allowing us to make a Doppler reconstruction of its 3-dimensional structure structure. In the center of the remnant, we find relatively pristine ejecta that have not yet reached Cas A's reverse shock or interacted with the circumstellar environment. We observe O, Si, and S emission. These ejecta can form both sheet-like structures as well as filaments. Si and O, which come from different nucleosynthetic layers of the star, are observed to be coincident in some regions, and separated by >500 km s -1 in others. Observed ejecta traveling toward us are, on average, ˜800 km s -1 slower than the material traveling away from us. We compare our observations to recent supernova explosion models and find that no single model can simultaneously reproduce all the observed features. However, models of different supernova explosions can collectively produce the observed geometries and structures of the emission interior to Cas A's reverse shock. We use the results from the models to address the conditions during the supernova explosion, concentrating on asymmetries in the shock structure. We also predict that the back surface of Cassiopeia A will begin brightening in ∼30 years, and the front surface in ˜100 years. We then used similar observations from 3 regions on Cas A's reverse shock in order to create more 3-dimensional maps. In these regions, we observe supernova ejecta both immediately before and during the shock-ejecta interaction. We determine that the

  11. Integrated Medical Model (IMM) 4.0 Enhanced Functionalities

    NASA Technical Reports Server (NTRS)

    Young, M.; Keenan, A. B.; Saile, L.; Boley, L. A.; Walton, M. E.; Shah, R. V.; Kerstman, E. L.; Myers, J. G.

    2015-01-01

    The Integrated Medical Model is a probabilistic simulation model that uses input data on 100 medical conditions to simulate expected medical events, the resources required to treat, and the resulting impact to the mission for specific crew and mission characteristics. The newest development version of IMM, IMM v4.0, adds capabilities that remove some of the conservative assumptions that underlie the current operational version, IMM v3. While IMM v3 provides the framework to simulate whether a medical event occurred, IMMv4 also simulates when the event occurred during a mission timeline. This allows for more accurate estimation of mission time lost and resource utilization. In addition to the mission timeline, IMMv4.0 features two enhancements that address IMM v3 assumptions regarding medical event treatment. Medical events in IMMv3 are assigned the untreated outcome if any resource required to treat the event was unavailable. IMMv4 allows for partially treated outcomes that are proportional to the amount of required resources available, thus removing the dichotomous treatment assumption. An additional capability IMMv4 is to use an alternative medical resource when the primary resource assigned to the condition is depleted, more accurately reflecting the real-world system. The additional capabilities defining IMM v4.0the mission timeline, partial treatment, and alternate drug result in more realistic predicted mission outcomes. The primary model outcomes of IMM v4.0 for the ISS6 mission, including mission time lost, probability of evacuation, and probability of loss of crew life, are be compared to those produced by the current operational version of IMM to showcase enhanced prediction capabilities.

  12. Morphological analysis and preoperative simulation of a double-chambered right ventricle using 3-dimensional printing technology.

    PubMed

    Shirakawa, Takashi; Koyama, Yasushi; Mizoguchi, Hiroki; Yoshitatsu, Masao

    2016-05-01

    We present a case of a double-chambered right ventricle in adulthood, in which we tried a detailed morphological assessment and preoperative simulation using 3-dimensional (3D) heart models for improved surgical planning. Polygonal object data for the heart were constructed from computed tomography images of this patient, and transferred to a desktop 3D printer to print out models in actual size. Medical staff completed all of the work processes. Because the 3D heart models were examined by hand, observed from various viewpoints and measured by callipers with ease, we were able to create an image of the complete form of the heart. The anatomical structure of an anomalous bundle was clearly observed, and surgical approaches to the lesion were simulated accurately. During surgery, we used an incision on the pulmonary infundibulum and resected three muscular components of the stenosis. The similarity between the models and the actual heart was excellent. As a result, the operation for this rare defect was performed safely and successfully. We concluded that the custom-made model was useful for morphological analysis and preoperative simulation. PMID:26860990

  13. Contribution of seismic processing to put up the scaffolding for the 3-dimensional study of deep sedimentary basins: the fundaments of trans-national 3D modelling in the project GeoMol

    NASA Astrophysics Data System (ADS)

    Capar, Laure

    2013-04-01

    Within the framework of the transnational project GeoMol geophysical and geological information on the entire Molasse Basin and on the Po Basin are gathered to build consistent cross-border 3D geological models based on borehole evidence and seismic data. Benefiting from important progress in seismic processing, these new models will provide some answers to various questions regarding the usage of subsurface resources, as there are geothermal energy, CO2 and gas storage, oil and gas production, and support decisions-making to national and local administrations as well as to industries. More than 28 000 km of 2D seismic lines are compiled reprocessed and harmonized. This work faces various problems like the vertical drop of more than 700 meters between West and East of the Molasse Basin and to al lesser extent in the Po Plain, the heterogeneities of the substratum, the large disparities between the period and parameters of seismic acquisition, and depending of their availability, the use of two types of seismic data, raw and processed seismic data. The main challenge is to harmonize all lines at the same reference level, amplitude and step of signal processing from France to Austria, spanning more than 1000 km, to avoid misfits at crossing points between seismic lines and artifacts at the country borders, facilitating the interpretation of the various geological layers in the Molasse Basin and Po Basin. A generalized stratigraphic column for the two basins is set up, representing all geological layers relevant to subsurface usage. This stratigraphy constitutes the harmonized framework for seismic reprocessing. In general, processed seismic data is available on paper at stack stage and the mandatory information to take these seismic lines to the final stage of processing, the migration step, are datum plane and replacement velocity. However several datum planes and replacement velocities were used during previous processing projects. Our processing sequence is to

  14. Contribution of seismic processing to put up the scaffolding for the 3-dimensional study of deep sedimentary basins: the fundaments of trans-national 3D modelling in the project GeoMol

    NASA Astrophysics Data System (ADS)

    Capar, Laure

    2013-04-01

    Within the framework of the transnational project GeoMol geophysical and geological information on the entire Molasse Basin and on the Po Basin are gathered to build consistent cross-border 3D geological models based on borehole evidence and seismic data. Benefiting from important progress in seismic processing, these new models will provide some answers to various questions regarding the usage of subsurface resources, as there are geothermal energy, CO2 and gas storage, oil and gas production, and support decisions-making to national and local administrations as well as to industries. More than 28 000 km of 2D seismic lines are compiled reprocessed and harmonized. This work faces various problems like the vertical drop of more than 700 meters between West and East of the Molasse Basin and to al lesser extent in the Po Plain, the heterogeneities of the substratum, the large disparities between the period and parameters of seismic acquisition, and depending of their availability, the use of two types of seismic data, raw and processed seismic data. The main challenge is to harmonize all lines at the same reference level, amplitude and step of signal processing from France to Austria, spanning more than 1000 km, to avoid misfits at crossing points between seismic lines and artifacts at the country borders, facilitating the interpretation of the various geological layers in the Molasse Basin and Po Basin. A generalized stratigraphic column for the two basins is set up, representing all geological layers relevant to subsurface usage. This stratigraphy constitutes the harmonized framework for seismic reprocessing. In general, processed seismic data is available on paper at stack stage and the mandatory information to take these seismic lines to the final stage of processing, the migration step, are datum plane and replacement velocity. However several datum planes and replacement velocities were used during previous processing projects. Our processing sequence is to

  15. Molecular Signatures in the Prevention of Radiation Damage by the Synergistic Effect of N-Acetyl Cysteine and Qingre Liyan Decoction, a Traditional Chinese Medicine, Using a 3-Dimensional Cell Culture Model of Oral Mucositis

    PubMed Central

    Lambros, Maria P.; Kondapalli, Lavanya; Parsa, Cyrus; Mulamalla, Hari Chandana; Orlando, Robert; Pon, Doreen; Huang, Ying; Chow, Moses S. S.

    2015-01-01

    Qingre Liyan decoction (QYD), a Traditional Chinese medicine, and N-acetyl cysteine (NAC) have been used to prevent radiation induced mucositis. This work evaluates the protective mechanisms of QYD, NAC, and their combination (NAC-QYD) at the cellular and transcriptional level. A validated organotypic model of oral mucosal consisting of a three-dimensional (3D) cell tissue-culture of primary human keratinocytes exposed to X-ray irradiation was used. Six hours after the irradiation, the tissues were evaluated by hematoxylin and eosin (H and E) and a TUNEL assay to assess histopathology and apoptosis, respectively. Total RNA was extracted and used for microarray gene expression profiling. The tissue-cultures treated with NAC-QYD preserved their integrity and showed no apoptosis. Microarray results revealed that the NAC-QYD caused the upregulation of genes encoding metallothioneins, HMOX1, and other components of the Nrf2 pathway, which protects against oxidative stress. DNA repair genes (XCP, GADD45G, RAD9, and XRCC1), protective genes (EGFR and PPARD), and genes of the NFκB pathway were upregulated. Finally, tissue-cultures treated prophylactically with NAC-QYD showed significant downregulation of apoptosis, cytokines and chemokines genes, and constrained damage-associated molecular patterns (DAMPs). NAC-QYD treatment involves the protective effect of Nrf2, NFκB, and DNA repair factors. PMID:25705238

  16. The regulation of cognitive enhancement devices: extending the medical model

    PubMed Central

    Maslen, Hannah; Douglas, Thomas; Cohen Kadosh, Roi; Levy, Neil; Savulescu, Julian

    2014-01-01

    This article presents a model for regulating cognitive enhancement devices (CEDs). Recently, it has become very easy for individuals to purchase devices which directly modulate brain function. For example, transcranial direct current stimulators are increasingly being produced and marketed online as devices for cognitive enhancement. Despite posing risks in a similar way to medical devices, devices that do not make any therapeutic claims do not have to meet anything more than basic product safety standards. We present the case for extending existing medical device legislation to cover CEDs. Medical devices and CEDs operate by the same or similar mechanisms and pose the same or similar risks. This fact coupled with the arbitrariness of the line between treatment and enhancement count in favour of regulating these devices in the same way. In arguing for this regulatory model, the paper highlights potential challenges to its implementation, and suggests solutions. PMID:25243073

  17. Medical informatics: a model developed for diabetes education via telemedicine.

    PubMed

    Ubeyli, Elif Derya

    2009-04-01

    Fast developments in information and communication technology (ICT) have made it possible to develop new services for people. One of the most interesting areas is health care. Medical informatics is the discipline concerned with the systematic processing of data, information and knowledge in medicine and health care. Information services, medical decision support systems and telemedicine are becoming important tools for medical professionals and also people who are interested in health related information. Medical decision support aims at providing health care professionals with therapy guidelines directly at the point of care. Telemedicine is the use of modern telecommunications and information technologies (IT) for the provision of clinical care to individuals at a distance and transmission of information to provide that care. In the present study, usage of IT in medicine, medical decision support systems, computerized medical measurements, patient education and network connectivity were described. A model for risk evaluation, data collection and education of undiagnosed diabetes using the world wide web (www) was presented. PMID:19397096

  18. The Use of the Integrated Medical Model for Forecasting and Mitigating Medical Risks for a Near-Earth Asteroid Mission

    NASA Technical Reports Server (NTRS)

    Kerstman, Eric; Saile, Lynn; Freire de Carvalho, Mary; Myers, Jerry; Walton, Marlei; Butler, Douglas; Lopez, Vilma

    2011-01-01

    Introduction The Integrated Medical Model (IMM) is a decision support tool that is useful to space flight mission managers and medical system designers in assessing risks and optimizing medical systems. The IMM employs an evidence-based, probabilistic risk assessment (PRA) approach within the operational constraints of space flight. Methods Stochastic computational methods are used to forecast probability distributions of medical events, crew health metrics, medical resource utilization, and probability estimates of medical evacuation and loss of crew life. The IMM can also optimize medical kits within the constraints of mass and volume for specified missions. The IMM was used to forecast medical evacuation and loss of crew life probabilities, as well as crew health metrics for a near-earth asteroid (NEA) mission. An optimized medical kit for this mission was proposed based on the IMM simulation. Discussion The IMM can provide information to the space program regarding medical risks, including crew medical impairment, medical evacuation and loss of crew life. This information is valuable to mission managers and the space medicine community in assessing risk and developing mitigation strategies. Exploration missions such as NEA missions will have significant mass and volume constraints applied to the medical system. Appropriate allocation of medical resources will be critical to mission success. The IMM capability of optimizing medical systems based on specific crew and mission profiles will be advantageous to medical system designers. Conclusion The IMM is a decision support tool that can provide estimates of the impact of medical events on human space flight missions, such as crew impairment, evacuation, and loss of crew life. It can be used to support the development of mitigation strategies and to propose optimized medical systems for specified space flight missions. Learning Objectives The audience will learn how an evidence-based decision support tool can be

  19. Integrated Medical Model Project - Overview and Summary of Historical Application

    NASA Technical Reports Server (NTRS)

    Myers, J.; Boley, L.; Butler, D.; Foy, M.; Goodenow, D.; Griffin, D.; Keenan, A.; Kerstman, E.; Melton, S.; McGuire, K.; Saile, L.; Shah, R.; Garcia, Y.; Sirmons, B.; Walton, M.

    2015-01-01

    Introduction: The Integrated Medical Model (IMM) Project represents one aspect of NASA's Human Research Program (HRP) to quantitatively assess medical risks to astronauts for existing operational missions as well as missions associated with future exploration and commercial space flight ventures. The IMM takes a probabilistic approach to assessing the likelihood and specific outcomes of one hundred medical conditions within the envelope of accepted space flight standards of care over a selectable range of mission capabilities. A specially developed Integrated Medical Evidence Database (iMED) maintains evidence-based, organizational knowledge across a variety of data sources. Since becoming operational in 2011, version 3.0 of the IMM, the supporting iMED, and the expertise of the IMM project team have contributed to a wide range of decision and informational processes for the space medical and human research community. This presentation provides an overview of the IMM conceptual architecture and range of application through examples of actual space flight community questions posed to the IMM project. Methods: Figure 1 [see document] illustrates the IMM modeling system and scenario process. As illustrated, the IMM computational architecture is based on Probabilistic Risk Assessment techniques. Nineteen assumptions and limitations define the IMM application domain. Scenario definitions include crew medical attributes and mission specific details. The IMM forecasts probabilities of loss of crew life (LOCL), evacuation (EVAC), quality time lost during the mission, number of medical resources utilized and the number and type of medical events by combining scenario information with in-flight, analog, and terrestrial medical information stored in the iMED. In addition, the metrics provide the integrated information necessary to estimate optimized in-flight medical kit contents under constraints of mass and volume or acceptable level of mission risk. Results and Conclusions

  20. Assessment of Medical Risks and Optimization of their Management using Integrated Medical Model

    NASA Technical Reports Server (NTRS)

    Fitts, Mary A.; Madurai, Siram; Butler, Doug; Kerstman, Eric; Risin, Diana

    2008-01-01

    The Integrated Medical Model (IMM) Project is a software-based technique that will identify and quantify the medical needs and health risks of exploration crew members during space flight and evaluate the effectiveness of potential mitigation strategies. The IMM Project employs an evidence-based approach that will quantify probability and consequences of defined in-flight medical risks, mitigation strategies, and tactics to optimize crew member health. Using stochastic techniques, the IMM will ultimately inform decision makers at both programmatic and institutional levels and will enable objective assessment of crew health and optimization of mission success using data from relevant cohort populations and from the astronaut population. The objectives of the project include: 1) identification and documentation of conditions that may occur during exploration missions (Baseline Medical Conditions List [BMCL), 2) assessment of the likelihood of conditions in the BMCL occurring during exploration missions (incidence rate), 3) determination of the risk associated with these conditions and quantify in terms of end states (Loss of Crew, Loss of Mission, Evacuation), 4) optimization of in-flight hardware mass, volume, power, bandwidth and cost for a given level of risk or uncertainty, and .. validation of the methodologies used.

  1. Use of Animal Models to Develop Antiaddiction Medications

    PubMed Central

    Gardner, Eliot L.

    2008-01-01

    Although addiction is a uniquely human phenomenon, some of its pathognomonic features can be modeled at the animal level. Such features include the euphoric “high” produced by acute administration of addictive drugs; the dysphoric “crash” produced by acute withdrawal, drug-seeking, and drug-taking behaviors; and relapse to drug-seeking behavior after achieving successful abstinence. Animal models exist for each of these features. In this review, I focus on various animal models of addiction and how they can be used to search for clinically effective antiaddiction medications. I conclude by noting some of the new and novel medications that have been developed preclinically using such models and the hope for further developments along such lines. PMID:18803910

  2. Multimodality 3-Dimensional Image Integration for Congenital Cardiac Catheterization

    PubMed Central

    2014-01-01

    Cardiac catheterization procedures for patients with congenital and structural heart disease are becoming more complex. New imaging strategies involving integration of 3-dimensional images from rotational angiography, magnetic resonance imaging (MRI), computerized tomography (CT), and transesophageal echocardiography (TEE) are employed to facilitate these procedures. We discuss the current use of these new 3D imaging technologies and their advantages and challenges when used to guide complex diagnostic and interventional catheterization procedures in patients with congenital heart disease. PMID:25114757

  3. Leasing vs. owning a medical office: an analytical model.

    PubMed

    Tolbert, Samuel H; Wood, Carol P

    2007-01-01

    Physicians often face a major financial dilemma: To lease or own their medical office. This article takes a set of typical assumptions for a real estate market and analyzes the capital costs, cash flow, and investment implications of the option of leasing a medical office versus owning a similar property. The paper analyzes the financial aspects of each option and the impact on net physician income and potential return-on-investment. A model for analysis is presented that can be used by practitioners who advise physicians in such decision-making. PMID:18972995

  4. Ranking Medical Subject Headings using a factor graph model

    PubMed Central

    Wei, Wei; Demner-Fushman, Dina; Wang, Shuang; Jiang, Xiaoqian; Ohno-Machado, Lucila

    2015-01-01

    Automatically assigning MeSH (Medical Subject Headings) to articles is an active research topic. Recent work demonstrated the feasibility of improving the existing automated Medical Text Indexer (MTI) system, developed at the National Library of Medicine (NLM). Encouraged by this work, we propose a novel data-driven approach that uses semantic distances in the MeSH ontology for automated MeSH assignment. Specifically, we developed a graphical model to propagate belief through a citation network to provide robust MeSH main heading (MH) recommendation. Our preliminary results indicate that this approach can reach high Mean Average Precision (MAP) in some scenarios. PMID:26306236

  5. 3-Dimensional modeling of protein structures distinguishes closely related phytoplasmas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phytoplasmas (formerly mycoplasmalike organisms, MLOs) are cell wall-less bacteria that inhabit phloem tissue of plants and are transmitted from plant-to-plant by phloem-feeding insects. Numerous diseases affecting hundreds of plant species in many botanical families are attributed to infections by...

  6. Validation of medical modeling & simulation training devices and systems.

    PubMed

    Magee, J Harvey

    2003-01-01

    For almost a decade, research has been conducted in many areas of science to develop medical simulation training devices and even comprehensive training systems. To propel the field, the Telemedicine and Advanced Technology Research Center (TATRC), an agency of the United States Army Medical Research Materiel Command (USAMRMC), has been managing a portfolio of research projects in the area of Medical Modeling and Simulation (MM&S) since 1999. Significant progress has made to identify and harness enabling technologies. Generally, these developments can be categorized in four areas: (1) PC-based interactive multimedia, (2) Digitally Enhanced Mannequins, (3) Virtual Workbench, or "part-task", simulators, and (4) Total Immersion Virtual Reality (TIVR). Many medical simulation-training systems have shown great potential to improve medical training, but the potential shown has been based largely on anecdotal feedback from informal user studies. Formal assessment is needed to determine the degree to which simulator(s) train medical skills and the degree to which skills learned on a simulator transfer to the practice of care. A robust methodology is required as a basis for these assessments. Several scientific workshops sponsored in 2001 focused on algorithm and metrics development in support of surgical simulation. Also in 2001, TATRC chartered a Simulation Working Group (SWG) to develop a robust methodology upon which to base an assessment of the effectiveness of simulation training devices and systems. After the terrorist attacks of September 11, 2001, attention was redirected for a period, and progress was delayed. In the summer of 2002, TATRC chartered a follow-on group called the Validation, Metrics and Simulation (VMAS) Committee. The poster will highlight and summarize the development of the methodology and identify validation studies to be conducted (supported by various funding sources and research programs). The interaction between TATRC and the National Capital

  7. Military medical modeling and simulation in the 21st century.

    PubMed

    Moses, G; Magee, J H; Bauer, J J; Leitch, R

    2001-01-01

    As we enter the 21st century, military medicine struggles with critical issues. One of the most important issues is how to train medical personnel in peace for the realities of war. In April, 1998, The General Accounting Office (GAO) reported, "Military medical personnel have almost no chance during peacetime to practice battlefield trauma care skills. As a result, physicians both within and outside the Department of Defense (DOD) believe that military medical personnel are not prepared to provide trauma care to the severely injured soldiers in wartime. With some of today's training methods disappearing, the challenge of providing both initial; and sustainment training for almost 100,000 military medical personnel is becoming insurmountable. The "training gap" is huge and impediments to training are mounting. For example, restrictions on animal use are increasing and the cost of conducting live mass casualty exercises is prohibitive. Many medical simulation visionaries believe that four categories of medical simulation are emerging to address these challenges. These categories include PC-based multimedia, digital mannequins, virtual workbenches, and total immersion virtual reality (TIVR). The use of simulation training can provide a risk = free realistic learning environment for the spectrum of medical skills training, from buddy-aid to trauma surgery procedures. This will, in turn, enhance limited hands on training opportunities and revolutionize the way we train in peace to deliver medicine in war. High-fidelity modeling will permit manufacturers to prototype new devices before manufacture. Also, engineers will be able to test a device for themselves in a variety of simulated anatomical representations, permitting them to "practice medicine". PMID:11317763

  8. Medical simulation: Overview, and application to wound modelling and management

    PubMed Central

    Pai, Dinker R.; Singh, Simerjit

    2012-01-01

    Simulation in medical education is progressing in leaps and bounds. The need for simulation in medical education and training is increasing because of a) overall increase in the number of medical students vis-à-vis the availability of patients; b) increasing awareness among patients of their rights and consequent increase in litigations and c) tremendous improvement in simulation technology which makes simulation more and more realistic. Simulation in wound care can be divided into use of simulation in wound modelling (to test the effect of projectiles on the body) and simulation for training in wound management. Though this science is still in its infancy, more and more researchers are now devising both low-technology and high-technology (virtual reality) simulators in this field. It is believed that simulator training will eventually translate into better wound care in real patients, though this will be the subject of further research. PMID:23162218

  9. Conditioned Media From Adipose-Derived Stromal Cells Accelerates Healing in 3-Dimensional Skin Cultures.

    PubMed

    Collawn, Sherry S; Mobley, James A; Banerjee, N Sanjib; Chow, Louise T

    2016-04-01

    Wound healing involves a number of factors that results in the production of a "closed" wound. Studies have shown, in animal models, acceleration of wound healing with the addition of adipose-derived stromal cells (ADSC). The cause for the positive effect which these cells have on wound healing has not been elucidated. We have previously shown that addition of ADSC to the dermal equivalent in 3-dimensional skin cultures accelerates reepithelialization. We now demonstrate that conditioned media (CM) from cultured ADSC produced a similar rate of healing. This result suggests that a feedback from the 3-dimensional epithelial cultures to ADSC was not necessary to effect the accelerated reepithelialization. Mass spectrometry of CM from ADSC and primary human fibroblasts revealed differences in secretomes, some of which might have roles in the accelerating wound healing. Thus, the use of CM has provided some preliminary information on a possible mode of action. PMID:26954733

  10. Medical students' emotional development in early clinical experience: a model.

    PubMed

    Helmich, Esther; Bolhuis, Sanneke; Laan, Roland; Dornan, Tim; Koopmans, Raymond

    2014-08-01

    Dealing with emotions is a critical feature of professional behaviour. There are no comprehensive theoretical models, however, explaining how medical students learn about emotions. We aimed to explore factors affecting their emotions and how they learn to deal with emotions in themselves and others. During a first-year nursing attachment in hospitals and nursing homes, students wrote daily about their most impressive experiences, explicitly reporting what they felt, thought, and did. In a subsequent interview, they discussed those experiences in greater detail. Following a grounded theory approach, we conducted a constant comparative analysis, collecting and then interpreting data, and allowing the interpretation to inform subsequent data collection. Impressive experiences set up tensions, which gave rise to strong emotions. We identified four 'axes' along which tensions were experienced: 'idealism versus reality', 'critical distance versus adaptation', 'involvement versus detachment' and 'feeling versus displaying'. We found many factors, which influenced how respondents relieved those tensions. Their personal attributes and social relationships both inside and outside the medical community were important ones. Respondents' positions along the different dimensions, as determined by the balance between attributes and tensions, shaped their learning outcomes. Medical students' emotional development occurs through active participation in medical practice and having impressive experiences within relationships with patients and others on wards. Tensions along four dimensions give rise to strong emotions. Gaining insight into the many conditions that influence students' learning about emotions might support educators and supervisors in fostering medical students' emotional and professional development. PMID:23949724

  11. Role Modeling in the First 2 Years of Medical School.

    PubMed

    Obadia, Sharon J

    2015-08-01

    Role modeling opportunities for osteopathic physician teachers during a student's first 2 years of medical school are emerging as more colleges of osteopathic medicine strive to connect basic science didactics with clinically based learning activities. Examples of positive modeling by physician teachers during the first years of medical school are illustrated by 10 vignettes that can be incorporated into faculty development programs to increase awareness of such opportunities. The physician teacher in each vignette interacts with the student demonstrating desired professional behaviors. These vignettes also illustrate the effect of a positive "hidden curriculum" on a student's professional development. By recognizing these valuable teachable moments, teachers can incorporate role modeling into their daily practice. PMID:26214824

  12. Medical Students’ Perceptions of Clinical Teachers as Role Model

    PubMed Central

    Haider, Sonia Ijaz; Snead, David R. J.; Bari, Muhammad Furqan

    2016-01-01

    Introduction Role models facilitate student learning and assists in the development of professional identity. However, social organization and cultural values influence the choice of role models. Considering that the social organization and cultural values in South East Asia are different from other countries, it is important to know whether this affects the characteristics medical students look for in their role models in these societies. Methods A 32 item questionnaire was developed and self-administered to undergraduate medical students. Participants rated the characteristics on a three point scale (0 = not important, 1 = mildly important, 2 = very important). One way ANOVA and student's t-test were used to compare the groups. Results A total of 349 (65.23%) distributed questionnaires were returned. The highest ranked themes were teaching and facilitating learning, patient care and continuing professional development followed by communication and professionalism. Safe environment and guiding personal and professional development was indicated least important. Differences were also observed between scores obtained by males and females. Conclusion Globally there are attributes which are perceived as essential for role models, while others are considered desirable. An understanding of the attributes which are essential and desirable for role models can help medical educators devise strategies which can reinforce those attributes within their institutions. PMID:26959364

  13. The collaborative autonomy model of medical decision-making.

    PubMed

    Rubin, Michael A

    2014-04-01

    While the bioethical principle of beneficence originated in antiquity, the ascension of autonomy, or "self-rule," has redefined the physician-patient relationship to the extent that autonomy often dominates medical decision-making. Philosophical and social movements, medical research atrocities, consumerism, and case law have all had their influence on this paradigm shift. Consequently, the contemporary physician encounters an uncertainty in medical practice on how to resolve conflicts that arise in the pursuit of valuing both autonomy and beneficence. This is especially true in the practice of neurologic critical care where physicians may be advising comfort care measures for neurologically devastated patients while surrogates request physiologically futile interventions. This conundrum has been an important subject of the bioethics and social science literature but often this discourse is not disseminated to the clinicians confronting these issues. The purpose of this essay is to present a history of the principles of autonomy and beneficence and then present a shared medical decision-making model, collaborative autonomy, to provide guidance to neurologic critical care providers in how to resolve such dilemmas. Clinical vignettes will help illustrate the model. PMID:24233814

  14. Case-based reasoning to explain medical model exceptions.

    PubMed

    Schmidt, Rainer; Vorobieva, Olga

    2008-01-01

    In medicine many exceptions occur. In medical practise and in knowledge-based systems too, it is necessary to consider them and to deal with them appropriately. In medical studies and in research exceptions shall be explained. We present a system that helps to explain cases that do not fit into a theoretical hypothesis. Our starting points are situations where neither a well-developed theory nor reliable knowledge nor a proper case base is available. So, instead of reliable theoretical knowledge and intelligent experience, we have just some theoretical hypothesis and a set of measurements. In this paper, we propose to combine CBR with a statistical model. We use CBR to explain those cases that do not fit the model. The case base has to be set up incrementally, it contains the exceptional cases, and their explanations are the solutions, which can be used to help to explain further exceptional cases. PMID:18487741

  15. Modeling of bubble dynamics in relation to medical applications

    SciTech Connect

    Amendt, P.A.; London, R.A.; Strauss, M. |

    1997-03-12

    In various pulsed-laser medical applications, strong stress transients can be generated in advance of vapor bubble formation. To better understand the evolution of stress transients and subsequent formation of vapor bubbles, two-dimensional simulations are presented in channel or cylindrical geometry with the LATIS (LAser TISsue) computer code. Differences with one-dimensional modeling are explored, and simulated experimental conditions for vapor bubble generation are presented and compared with data. 22 refs., 8 figs.

  16. Novel 3-dimensional virtual hepatectomy simulation combined with real-time deformation

    PubMed Central

    Oshiro, Yukio; Yano, Hiroaki; Mitani, Jun; Kim, Sangtae; Kim, Jaejeong; Fukunaga, Kiyoshi; Ohkohchi, Nobuhiro

    2015-01-01

    AIM: To develop a novel 3-dimensional (3D) virtual hepatectomy simulation software, Liversim, to visualize the real-time deformation of the liver. METHODS: We developed a novel real-time virtual hepatectomy simulation software program called Liversim. The software provides 4 basic functions: viewing 3D models from arbitrary directions, changing the colors and opacities of the models, deforming the models based on user interaction, and incising the liver parenchyma and intrahepatic vessels based on user operations. From April 2010 through 2013, 99 patients underwent virtual hepatectomies that used the conventional software program SYNAPSE VINCENT preoperatively. Between April 2012 and October 2013, 11 patients received virtual hepatectomies using the novel software program Liversim; these hepatectomies were performed both preoperatively and at the same that the actual hepatectomy was performed in an operating room. The perioperative outcomes were analyzed between the patients for whom SYNAPSE VINCENT was used and those for whom Liversim was used. Furthermore, medical students and surgical residents were asked to complete questionnaires regarding the new software. RESULTS: There were no obvious discrepancies (i.e., the emergence of branches in the portal vein or hepatic vein or the depth and direction of the resection line) between our simulation and the actual surgery during the resection process. The median operating time was 304 min (range, 110 to 846) in the VINCENT group and 397 min (range, 232 to 497) in the Liversim group (P = 0.30). The median amount of intraoperative bleeding was 510 mL (range, 18 to 5120) in the VINCENT group and 470 mL (range, 130 to 1600) in the Liversim group (P = 0.44). The median postoperative stay was 12 d (range, 6 to 100) in the VINCENT group and 13 d (range, 9 to 21) in the Liversim group (P = 0.36). There were no significant differences in the preoperative outcomes between the two groups. Liversim was not found to be clinically

  17. Medical applications of model-based dynamic thermography

    NASA Astrophysics Data System (ADS)

    Nowakowski, Antoni; Kaczmarek, Mariusz; Ruminski, Jacek; Hryciuk, Marcin; Renkielska, Alicja; Grudzinski, Jacek; Siebert, Janusz; Jagielak, Dariusz; Rogowski, Jan; Roszak, Krzysztof; Stojek, Wojciech

    2001-03-01

    The proposal to use active thermography in medical diagnostics is promising in some applications concerning investigation of directly accessible parts of the human body. The combination of dynamic thermograms with thermal models of investigated structures gives attractive possibility to make internal structure reconstruction basing on different thermal properties of biological tissues. Measurements of temperature distribution synchronized with external light excitation allow registration of dynamic changes of local temperature dependent on heat exchange conditions. Preliminary results of active thermography applications in medicine are discussed. For skin and under- skin tissues an equivalent thermal model may be determined. For the assumed model its effective parameters may be reconstructed basing on the results of transient thermal processes. For known thermal diffusivity and conductivity of specific tissues the local thickness of a two or three layer structure may be calculated. Results of some medical cases as well as reference data of in vivo study on animals are presented. The method was also applied to evaluate the state of the human heart during the open chest cardio-surgical interventions. Reference studies of evoked heart infarct in pigs are referred, too. We see the proposed new in medical applications technique as a promising diagnostic tool. It is a fully non-invasive, clean, handy, fast and affordable method giving not only qualitative view of investigated surfaces but also an objective quantitative measurement result, accurate enough for many applications including fast screening of affected tissues.

  18. A complementary model for medical subspecialty training in South Africa.

    PubMed

    Dalmeyer, J Paul F; Struwig, Miemie; Kruger, Thinus F

    2016-01-01

    The shortage of healthcare workers and doctors in the developing world compared with the developed world is problematic, and will continue to be so owing to the ongoing migration of qualified professionals and the inability of the state to remedy the shortfalls. This will seriously hamper the government's National Health Insurance plan and the sustainability of South Africa (SA)'s healthcare sector. Furthermore, it is well known that the duration of medical training in SA is exceptionally long, which discourages trainees. Medical corporates have taken a limited initiative to fund education projects in collaboration with academic institutions. These projects have been unstructured, mostly ad hoc, and poorly co-ordinated. The private corporate medical sector has expressed a desire to become involved on a much larger scale by means of more formalised structures. Given this background, the primary objective of our research was to develop a business model to complement the current academic medical subspecialty training. PMID:27138655

  19. Late-life depression: a model for medical classification.

    PubMed

    Alexopoulos, George S; Schultz, Susan K; Lebowitz, Barry D

    2005-08-15

    Geriatric psychiatric syndromes might serve as the starting point for a medical classification of psychiatric disorders, because their medical and neurological comorbidity and their clinical, neuropsychological, and neuroimaging features often reflect specific brain abnormalities. Geriatric syndromes, however, consist of complex behaviors that are unlikely to be caused by single lesions. We propose a model in which aging-related changes in specific brain structures increase the propensity for the development of certain psychiatric syndromes. The predisposing factors are distinct from the mechanisms mediating the expression of a syndromic state, much like hypertension is distinct from stroke, but constitutes a morbid vulnerability. We argue that research seeking to identify both brain abnormalities conferring vulnerability as well as the mediating mechanisms of symptomatology has the potential to lead to a medical classification of psychiatric disorders. In addition, a medical classification can guide the effort to improve treatment and prevention of psychiatric disorders as it can direct therapeutic efforts to the underlying predisposing abnormalities, the syndrome-mediating mechanisms, and to development of behavioral skills needed for coping with adversity and disability. PMID:16026764

  20. Medicalization in psychiatry: the medical model, descriptive diagnosis, and lost knowledge.

    PubMed

    Sedler, Mark J

    2016-06-01

    Medicalization was the theme of the 29th European Conference on Philosophy of Medicine and Health Care that included a panel session on the DSM and mental health. Philosophical critiques of the medical model in psychiatry suffer from endemic assumptions that fail to acknowledge the real world challenges of psychiatric nosology. The descriptive model of classification of the DSM 3-5 serves a valid purpose in the absence of known etiologies for the majority of psychiatric conditions. However, a consequence of the "atheoretical" approach of the DSM is rampant epistemological confusion, a shortcoming that can be ameliorated by importing perspectives from the work of Jaspers and McHugh. Finally, contemporary psychiatry's over-reliance on neuroscience and pharmacotherapy has led to a reductionist agenda that is antagonistic to the inherently pluralistic nature of psychiatry.  As a result,  the field has suffered a loss of knowledge that may be difficult to recover. PMID:26602907

  1. Correlation model for a class of medical images

    NASA Astrophysics Data System (ADS)

    Zhang, Ya-Qin; Loew, Murray H.; Pickholtz, Raymond L.

    1991-06-01

    In this paper, correlation properties of a class of chest X-ray medical images are examined and different 1-D and 2-D correlation models are applied to this class of image sources. Correlation structures for different scanning methods including row-by-row, column-by- column, diagonal and Peano are compared. It is suggested that the Peano scanning best reserves the inter-pixel correlation, which coincides with an earlier observation made by Lempel and Ziv. The rate-distortion properties are also discussed in terms of different 1-D and 2-D correlation models.

  2. Incorporating a 3-dimensional printer into the management of early-stage cervical cancer.

    PubMed

    Baek, Min-Hyun; Kim, Dae-Yeon; Kim, Namkug; Rhim, Chae Chun; Kim, Jong-Hyeok; Nam, Joo-Hyun

    2016-08-01

    We used a 3-dimensional (3D) printer to create anatomical replicas of real lesions and tested its application in cervical cancer. Our study patient decided to undergo radical hysterectomy after seeing her 3D model which was then used to plan and simulate this surgery. Using 3D printers to create patient-specific 3D tumor models may aid cervical cancer patients make treatment decisions. This technology will lead to better surgical and oncological outcomes for cervical cancer patients. J. Surg. Oncol. 2016;114:150-152. © 2016 Wiley Periodicals, Inc. PMID:27222318

  3. Overcoming barriers to development of cooperative medical decision support models.

    PubMed

    Hudson, Donna L; Cohen, Maurice E

    2012-01-01

    Attempts to automate the medical decision making process have been underway for the at least fifty years, beginning with data-based approaches that relied chiefly on statistically-based methods. Approaches expanded to include knowledge-based systems, both linear and non-linear neural networks, agent-based systems, and hybrid methods. While some of these models produced excellent results none have been used extensively in medical practice. In order to move these methods forward into practical use, a number of obstacles must be overcome, including validation of existing systems on large data sets, development of methods for including new knowledge as it becomes available, construction of a broad range of decision models, and development of non-intrusive methods that allow the physician to use these decision aids in conjunction with, not instead of, his or her own medical knowledge. None of these four requirements will come easily. A cooperative effort among researchers, including practicing MDs, is vital, particularly as more information on diseases and their contributing factors continues to expand resulting in more parameters than the human decision maker can process effectively. In this article some of the basic structures that are necessary to facilitate the use of an automated decision support system are discussed, along with potential methods for overcoming existing barriers. PMID:23366358

  4. 3-Dimensional quantitative detection of nanoparticle content in biological tissue samples after local cancer treatment

    NASA Astrophysics Data System (ADS)

    Rahn, Helene; Alexiou, Christoph; Trahms, Lutz; Odenbach, Stefan

    2014-06-01

    X-ray computed tomography is nowadays used for a wide range of applications in medicine, science and technology. X-ray microcomputed tomography (XµCT) follows the same principles used for conventional medical CT scanners, but improves the spatial resolution to a few micrometers. We present an example of an application of X-ray microtomography, a study of 3-dimensional biodistribution, as along with the quantification of nanoparticle content in tumoral tissue after minimally invasive cancer therapy. One of these minimal invasive cancer treatments is magnetic drug targeting, where the magnetic nanoparticles are used as controllable drug carriers. The quantification is based on a calibration of the XµCT-equipment. The developed calibration procedure of the X-ray-µCT-equipment is based on a phantom system which allows the discrimination between the various gray values of the data set. These phantoms consist of a biological tissue substitute and magnetic nanoparticles. The phantoms have been studied with XµCT and have been examined magnetically. The obtained gray values and nanoparticle concentration lead to a calibration curve. This curve can be applied to tomographic data sets. Accordingly, this calibration enables a voxel-wise assignment of gray values in the digital tomographic data set to nanoparticle content. Thus, the calibration procedure enables a 3-dimensional study of nanoparticle distribution as well as concentration.

  5. Deformable part models for object detection in medical images

    PubMed Central

    2014-01-01

    Background Object detection in 3-D medical images is often necessary for constraining a segmentation or registration task. It may be a task in its own right as well, when instances of a structure, e.g. the lymph nodes, are searched. Problems from occlusion, illumination and projection do not arise, making the problem simpler than object detection in photographies. However, objects of interest are often not well contrasted against the background. Influence from noise and other artifacts is much stronger and shape and appearance may vary substantially within a class. Methods Deformable models capture the characteristic shape of an anatomic object and use constrained deformation for hypothesing object boundaries in image regions of low or non-existing contrast. Learning these constraints requires a large sample data base. We show that training may be replaced by readily available user knowledge defining a prototypical deformable part model. If structures have a strong part-relationship, or if they may be found based on spatially related guiding structures, or if the deformation is rather restricted, the supporting data information suffices for solving the detection task. We use a finite element model to represent anatomic variation by elastic deformation. Complex shape variation may be represented by a hierarchical model with simpler part variation. The hierarchy may be represented explicitly as a hierarchy of sub-shapes, or implicitly by a single integrated model. Data support and model deformation of the complete model can be represented by an energy term, serving as quality-of-fit function for object detection. Results The model was applied to detection and segmentation tasks in various medical applications in 2- and 3-D scenes. It has been shown that model fitting and object detection can be carried out efficiently by a combination of a local and global search strategy using models that are parameterized for the different tasks. Conclusions A part-based elastic

  6. Adaptive predictive multiplicative autoregressive model for medical image compression.

    PubMed

    Chen, Z D; Chang, R F; Kuo, W J

    1999-02-01

    In this paper, an adaptive predictive multiplicative autoregressive (APMAR) method is proposed for lossless medical image coding. The adaptive predictor is used for improving the prediction accuracy of encoded image blocks in our proposed method. Each block is first adaptively predicted by one of the seven predictors of the JPEG lossless mode and a local mean predictor. It is clear that the prediction accuracy of an adaptive predictor is better than that of a fixed predictor. Then the residual values are processed by the MAR model with Huffman coding. Comparisons with other methods [MAR, SMAR, adaptive JPEG (AJPEG)] on a series of test images show that our method is suitable for reversible medical image compression. PMID:10232675

  7. Scene-of-crime analysis by a 3-dimensional optical digitizer: a useful perspective for forensic science.

    PubMed

    Sansoni, Giovanna; Cattaneo, Cristina; Trebeschi, Marco; Gibelli, Daniele; Poppa, Pasquale; Porta, Davide; Maldarella, Monica; Picozzi, Massimo

    2011-09-01

    Analysis and detailed registration of the crime scene are of the utmost importance during investigations. However, this phase of activity is often affected by the risk of loss of evidence due to the limits of traditional scene of crime registration methods (ie, photos and videos). This technical note shows the utility of the application of a 3-dimensional optical digitizer on different crime scenes. This study aims in fact at verifying the importance and feasibility of contactless 3-dimensional reconstruction and modeling by optical digitization to achieve an optimal registration of the crime scene. PMID:21811148

  8. A crowdsourcing model for creating preclinical medical education study tools.

    PubMed

    Bow, Hansen C; Dattilo, Jonathan R; Jonas, Andrea M; Lehmann, Christoph U

    2013-06-01

    During their preclinical course work, medical students must memorize and recall substantial amounts of information. Recent trends in medical education emphasize collaboration through team-based learning. In the technology world, the trend toward collaboration has been characterized by the crowdsourcing movement. In 2011, the authors developed an innovative approach to team-based learning that combined students' use of flashcards to master large volumes of content with a crowdsourcing model, using a simple informatics system to enable those students to share in the effort of generating concise, high-yield study materials. The authors used Google Drive and developed a simple Java software program that enabled students to simultaneously access and edit sets of questions and answers in the form of flashcards. Through this crowdsourcing model, medical students in the class of 2014 at the Johns Hopkins University School of Medicine created a database of over 16,000 questions that corresponded to the Genes to Society basic science curriculum. An analysis of exam scores revealed that students in the class of 2014 outperformed those in the class of 2013, who did not have access to the flashcard system, and a survey of students demonstrated that users were generally satisfied with the system and found it a valuable study tool. In this article, the authors describe the development and implementation of their crowdsourcing model for creating study materials, emphasize its simplicity and user-friendliness, describe its impact on students' exam performance, and discuss how students in any educational discipline could implement a similar model of collaborative learning. PMID:23619061

  9. Architecture for Integrated Medical Model Dynamic Probabilistic Risk Assessment

    NASA Technical Reports Server (NTRS)

    Jaworske, D. A.; Myers, J. G.; Goodenow, D.; Young, M.; Arellano, J. D.

    2016-01-01

    Probabilistic Risk Assessment (PRA) is a modeling tool used to predict potential outcomes of a complex system based on a statistical understanding of many initiating events. Utilizing a Monte Carlo method, thousands of instances of the model are considered and outcomes are collected. PRA is considered static, utilizing probabilities alone to calculate outcomes. Dynamic Probabilistic Risk Assessment (dPRA) is an advanced concept where modeling predicts the outcomes of a complex system based not only on the probabilities of many initiating events, but also on a progression of dependencies brought about by progressing down a time line. Events are placed in a single time line, adding each event to a queue, as managed by a planner. Progression down the time line is guided by rules, as managed by a scheduler. The recently developed Integrated Medical Model (IMM) summarizes astronaut health as governed by the probabilities of medical events and mitigation strategies. Managing the software architecture process provides a systematic means of creating, documenting, and communicating a software design early in the development process. The software architecture process begins with establishing requirements and the design is then derived from the requirements.

  10. Group Mental Health Approaches--Medical and Non-Medical Models.

    ERIC Educational Resources Information Center

    Stein, Aaron

    Medical and non-medical group mental health approaches are discussed. In the medical approach groups are set up for the treatment of the psychopathology of the members and group therapy or group psychotherapy methods are utilized. The clients are selected by the therapist who determines what kind of group would be most beneficial for the patient.…

  11. 3-Dimensional Imaging Modalities for Phenotyping Genetically Engineered Mice

    PubMed Central

    Powell, K. A.; Wilson, D.

    2013-01-01

    A variety of 3-dimensional (3D) digital imaging modalities are available for whole-body assessment of genetically engineered mice: magnetic resonance microscopy (MRM), X-ray microcomputed tomography (microCT), optical projection tomography (OPT), episcopic and cryoimaging, and ultrasound biomicroscopy (UBM). Embryo and adult mouse phenotyping can be accomplished at microscopy or near microscopy spatial resolutions using these modalities. MRM and microCT are particularly well-suited for evaluating structural information at the organ level, whereas episcopic and OPT imaging provide structural and functional information from molecular fluorescence imaging at the cellular level. UBM can be used to monitor embryonic development longitudinally in utero. Specimens are not significantly altered during preparation, and structures can be viewed in their native orientations. Technologies for rapid automated data acquisition and high-throughput phenotyping have been developed and continually improve as this exciting field evolves. PMID:22146851

  12. Modeling past, current, and future time in medical databases.

    PubMed Central

    Kouramajian, V.; Fowler, J.

    1994-01-01

    Recent research has focused on increasing the power of medical information systems by incorporating time into the database system. A problem with much of this research is that it fails to differentiate between historical time and future time. The concept of bitemporal lifespan presented in this paper overcomes this deficiency. Bitemporal lifespan supports the concepts of valid time and transaction time and allows the integration of past, current, and future information in a unified model. The concept of bitemporal lifespan is presented within the framework of the Extended Entity-Relationship model. This model permits the characterization of temporal properties of entities, relationships, and attributes. Bitemporal constraints are defined that must hold between entities forming "isa" hierarchies and between entities and relationships. Finally, bitemporal extensions are presented for database query languages in order to provide natural high-level operators for bitemporal query expressions. PMID:7949941

  13. Anti-relapse medications: Preclinical models for drug addiction treatment

    PubMed Central

    Yahyavi-Firouz-Abadi, Noushin; See, Ronald E.

    2009-01-01

    Addiction is a chronic relapsing brain disease and treatment of relapse to drug-seeking is considered the most challenging part of treating addictive disorders. Relapse can be modeled in laboratory animals using reinstatement paradigms, whereby behavioral responding for a drug is extinguished and then reinstated by different trigger factors, such as environmental cues or stress. In this review, we first describe currently used animal models of relapse, different relapse triggering factors, and the validity of this model to assess relapse in humans. We further summarize the growing body of pharmacological interventions that have shown some promise in treating relapse to psychostimulant addiction. Moreover, we present an overview on the drugs tested in cocaine or methamphetamine addicts and examine the overlap of existing preclinical and clinical data. Finally, based on recent advances in our understanding of the neurobiology of relapse and published preclinical data, we highlight the most promising areas for future anti-relapse medication development. PMID:19683019

  14. Medical image segmentation using object atlas versus object cloud models

    NASA Astrophysics Data System (ADS)

    Phellan, Renzo; Falcão, Alexandre X.; Udupa, Jayaram K.

    2015-03-01

    Medical image segmentation is crucial for quantitative organ analysis and surgical planning. Since interactive segmentation is not practical in a production-mode clinical setting, automatic methods based on 3D object appearance models have been proposed. Among them, approaches based on object atlas are the most actively investigated. A key drawback of these approaches is that they require a time-costly image registration process to build and deploy the atlas. Object cloud models (OCM) have been introduced to avoid registration, considerably speeding up the whole process, but they have not been compared to object atlas models (OAM). The present paper fills this gap by presenting a comparative analysis of the two approaches in the task of individually segmenting nine anatomical structures of the human body. Our results indicate that OCM achieve a statistically significant better accuracy for seven anatomical structures, in terms of Dice Similarity Coefficient and Average Symmetric Surface Distance.

  15. Can We Trust Computational Modeling for Medical Applications?

    NASA Technical Reports Server (NTRS)

    Mulugeta, Lealem; Walton, Marlei; Nelson, Emily; Myers, Jerry

    2015-01-01

    Operations in extreme environments such as spaceflight pose human health risks that are currently not well understood and potentially unanticipated. In addition, there are limited clinical and research data to inform development and implementation of therapeutics for these unique health risks. In this light, NASA's Human Research Program (HRP) is leveraging biomedical computational models and simulations (M&S) to help inform, predict, assess and mitigate spaceflight health and performance risks, and enhance countermeasure development. To ensure that these M&S can be applied with confidence to the space environment, it is imperative to incorporate a rigorous verification, validation and credibility assessment (VV&C) processes to ensure that the computational tools are sufficiently reliable to answer questions within their intended use domain. In this presentation, we will discuss how NASA's Integrated Medical Model (IMM) and Digital Astronaut Project (DAP) have successfully adapted NASA's Standard for Models and Simulations, NASA-STD-7009 (7009) to achieve this goal. These VV&C methods are also being leveraged by organization such as the Food and Drug Administration (FDA), National Institute of Health (NIH) and the American Society of Mechanical Engineers (ASME) to establish new M&S VV&C standards and guidelines for healthcare applications. Similarly, we hope to provide some insight to the greater aerospace medicine community on how to develop and implement M&S with sufficient confidence to augment medical research and operations.

  16. Conceptual Modeling for the Unified Medical Language System

    PubMed Central

    Barr, Charles E.; Komorowski, Henryk Jan; Pattison-Gordon, Edward; Greenes, Robert A.

    1988-01-01

    The Unified Medical Language System was proposed by the National Library of Medicine to facilitate the exchange and utilization of information from multiple sources. We are using semantic networks as the knowledge representation scheme in a prototype system to explore how to accomplish these goals. Conceptual modeling helps define a complete and consistent set of objects and relationships to include in the semantic net. Both top-down and bottom-up approaches were found useful in the seven step process of building the semantic network. Theoretical and practical issues are discussed as well as future extensions to the current prototype.

  17. A geometric snake model for segmentation of medical imagery.

    PubMed

    Yezzi, A; Kichenassamy, S; Kumar, A; Olver, P; Tannenbaum, A

    1997-04-01

    In this note, we employ the new geometric active contour models formulated in [25] and [26] for edge detection and segmentation of magnetic resonance imaging (MRI), computed tomography (CT), and ultrasound medical imagery. Our method is based on defining feature-based metrics on a given image which in turn leads to a novel snake paradigm in which the feature of interest may be considered to lie at the bottom of a potential well. Thus, the snake is attracted very quickly and efficiently to the desired feature. PMID:9101329

  18. Additive Manufacturing of Medical Models--Applications in Rhinology.

    PubMed

    Raos, Pero; Klapan, Ivica; Galeta, Tomislav

    2015-09-01

    In the paper we are introducing guidelines and suggestions for use of 3D image processing SW in head pathology diagnostic and procedures for obtaining physical medical model by additive manufacturing/rapid prototyping techniques, bearing in mind the improvement of surgery performance, its maximum security and faster postoperative recovery of patients. This approach has been verified in two case reports. In the treatment we used intelligent classifier-schemes for abnormal patterns using computer-based system for 3D-virtual and endoscopic assistance in rhinology, with appropriate visualization of anatomy and pathology within the nose, paranasal sinuses, and scull base area. PMID:26898064

  19. Design of 3-dimensional complex airplane configurations with specified pressure distribution via optimization

    NASA Technical Reports Server (NTRS)

    Kubrynski, Krzysztof

    1991-01-01

    A subcritical panel method applied to flow analysis and aerodynamic design of complex aircraft configurations is presented. The analysis method is based on linearized, compressible, subsonic flow equations and indirect Dirichlet boundary conditions. Quadratic dipol and linear source distribution on flat panels are applied. In the case of aerodynamic design, the geometry which minimizes differences between design and actual pressure distribution is found iteratively, using numerical optimization technique. Geometry modifications are modeled by surface transpiration concept. Constraints in respect to resulting geometry can be specified. A number of complex 3-dimensional design examples are presented. The software is adopted to personal computers, and as result an unexpected low cost of computations is obtained.

  20. A 3-dimensional finite-difference method for calculating the dynamic coefficients of seals

    NASA Technical Reports Server (NTRS)

    Dietzen, F. J.; Nordmann, R.

    1989-01-01

    A method to calculate the dynamic coefficients of seals with arbitrary geometry is presented. The Navier-Stokes equations are used in conjunction with the k-e turbulence model to describe the turbulent flow. These equations are solved by a full 3-dimensional finite-difference procedure instead of the normally used perturbation analysis. The time dependence of the equations is introduced by working with a coordinate system rotating with the precession frequency of the shaft. The results of this theory are compared with coefficients calculated by a perturbation analysis and with experimental results.

  1. Using features of Arden Syntax with object-oriented medical data models for guideline modeling.

    PubMed Central

    Peleg, M.; Ogunyemi, O.; Tu, S.; Boxwala, A. A.; Zeng, Q.; Greenes, R. A.; Shortliffe, E. H.

    2001-01-01

    Computer-interpretable guidelines (CIGs) can deliver patient-specific decision support at the point of care. CIGs base their recommendations on eligibility and decision criteria that relate medical concepts to patient data. CIG models use expression languages for specifying these criteria, and define models for medical data to which the expressions can refer. In developing version 3 of the GuideLine Interchange Format (GLIF3), we used existing standards as the medical data model and expression language. We investigated the object-oriented HL7 Reference Information Model (RIM) as a default data model. We developed an expression language, called GEL, based on Arden Syntax's logic grammar. Together with other GLIF constructs, GEL reconciles incompatibilities between the data models of Arden Syntax and the HL7 RIM. These incompatibilities include Arden's lack of support for complex data types and time intervals, and the mismatch between Arden's single primary time and multiple time attributes of the HL7 RIM. PMID:11825243

  2. Sensitivity Analysis of the Integrated Medical Model for ISS Programs

    NASA Technical Reports Server (NTRS)

    Goodenow, D. A.; Myers, J. G.; Arellano, J.; Boley, L.; Garcia, Y.; Saile, L.; Walton, M.; Kerstman, E.; Reyes, D.; Young, M.

    2016-01-01

    Sensitivity analysis estimates the relative contribution of the uncertainty in input values to the uncertainty of model outputs. Partial Rank Correlation Coefficient (PRCC) and Standardized Rank Regression Coefficient (SRRC) are methods of conducting sensitivity analysis on nonlinear simulation models like the Integrated Medical Model (IMM). The PRCC method estimates the sensitivity using partial correlation of the ranks of the generated input values to each generated output value. The partial part is so named because adjustments are made for the linear effects of all the other input values in the calculation of correlation between a particular input and each output. In SRRC, standardized regression-based coefficients measure the sensitivity of each input, adjusted for all the other inputs, on each output. Because the relative ranking of each of the inputs and outputs is used, as opposed to the values themselves, both methods accommodate the nonlinear relationship of the underlying model. As part of the IMM v4.0 validation study, simulations are available that predict 33 person-missions on ISS and 111 person-missions on STS. These simulated data predictions feed the sensitivity analysis procedures. The inputs to the sensitivity procedures include the number occurrences of each of the one hundred IMM medical conditions generated over the simulations and the associated IMM outputs: total quality time lost (QTL), number of evacuations (EVAC), and number of loss of crew lives (LOCL). The IMM team will report the results of using PRCC and SRRC on IMM v4.0 predictions of the ISS and STS missions created as part of the external validation study. Tornado plots will assist in the visualization of the condition-related input sensitivities to each of the main outcomes. The outcomes of this sensitivity analysis will drive review focus by identifying conditions where changes in uncertainty could drive changes in overall model output uncertainty. These efforts are an integral

  3. The Integrated Medical Model - Optimizing In-flight Space Medical Systems to Reduce Crew Health Risk and Mission Impacts

    NASA Technical Reports Server (NTRS)

    Kerstman, Eric; Walton, Marlei; Minard, Charles; Saile, Lynn; Myers, Jerry; Butler, Doug; Lyengar, Sriram; Fitts, Mary; Johnson-Throop, Kathy

    2009-01-01

    The Integrated Medical Model (IMM) is a decision support tool used by medical system planners and designers as they prepare for exploration planning activities of the Constellation program (CxP). IMM provides an evidence-based approach to help optimize the allocation of in-flight medical resources for a specified level of risk within spacecraft operational constraints. Eighty medical conditions and associated resources are represented in IMM. Nine conditions are due to Space Adaptation Syndrome. The IMM helps answer fundamental medical mission planning questions such as What medical conditions can be expected? What type and quantity of medical resources are most likely to be used?", and "What is the probability of crew death or evacuation due to medical events?" For a specified mission and crew profile, the IMM effectively characterizes the sequence of events that could potentially occur should a medical condition happen. The mathematical relationships among mission and crew attributes, medical conditions and incidence data, in-flight medical resources, potential clinical and crew health end states are established to generate end state probabilities. A Monte Carlo computational method is used to determine the probable outcomes and requires up to 25,000 mission trials to reach convergence. For each mission trial, the pharmaceuticals and supplies required to diagnose and treat prevalent medical conditions are tracked and decremented. The uncertainty of patient response to treatment is bounded via a best-case, worst-case, untreated case algorithm. A Crew Health Index (CHI) metric, developed to account for functional impairment due to a medical condition, provides a quantified measure of risk and enables risk comparisons across mission scenarios. The use of historical in-flight medical data, terrestrial surrogate data as appropriate, and space medicine subject matter expertise has enabled the development of a probabilistic, stochastic decision support tool capable of

  4. Sensitivity analysis of geometric errors in additive manufacturing medical models.

    PubMed

    Pinto, Jose Miguel; Arrieta, Cristobal; Andia, Marcelo E; Uribe, Sergio; Ramos-Grez, Jorge; Vargas, Alex; Irarrazaval, Pablo; Tejos, Cristian

    2015-03-01

    Additive manufacturing (AM) models are used in medical applications for surgical planning, prosthesis design and teaching. For these applications, the accuracy of the AM models is essential. Unfortunately, this accuracy is compromised due to errors introduced by each of the building steps: image acquisition, segmentation, triangulation, printing and infiltration. However, the contribution of each step to the final error remains unclear. We performed a sensitivity analysis comparing errors obtained from a reference with those obtained modifying parameters of each building step. Our analysis considered global indexes to evaluate the overall error, and local indexes to show how this error is distributed along the surface of the AM models. Our results show that the standard building process tends to overestimate the AM models, i.e. models are larger than the original structures. They also show that the triangulation resolution and the segmentation threshold are critical factors, and that the errors are concentrated at regions with high curvatures. Errors could be reduced choosing better triangulation and printing resolutions, but there is an important need for modifying some of the standard building processes, particularly the segmentation algorithms. PMID:25649961

  5. Developing a semantic web model for medical differential diagnosis recommendation.

    PubMed

    Mohammed, Osama; Benlamri, Rachid

    2014-10-01

    In this paper we describe a novel model for differential diagnosis designed to make recommendations by utilizing semantic web technologies. The model is a response to a number of requirements, ranging from incorporating essential clinical diagnostic semantics to the integration of data mining for the process of identifying candidate diseases that best explain a set of clinical features. We introduce two major components, which we find essential to the construction of an integral differential diagnosis recommendation model: the evidence-based recommender component and the proximity-based recommender component. Both approaches are driven by disease diagnosis ontologies designed specifically to enable the process of generating diagnostic recommendations. These ontologies are the disease symptom ontology and the patient ontology. The evidence-based diagnosis process develops dynamic rules based on standardized clinical pathways. The proximity-based component employs data mining to provide clinicians with diagnosis predictions, as well as generates new diagnosis rules from provided training datasets. This article describes the integration between these two components along with the developed diagnosis ontologies to form a novel medical differential diagnosis recommendation model. This article also provides test cases from the implementation of the overall model, which shows quite promising diagnostic recommendation results. PMID:25178271

  6. A Conceptual Model of Medical Student Well-Being: Promoting Resilience and Preventing Burnout

    ERIC Educational Resources Information Center

    Dunn, Laura B.; Iglewicz, Alana; Moutier, Christine

    2008-01-01

    Objective: This article proposes and illustrates a conceptual model of medical student well-being. Method: The authors reviewed the literature on medical student stress, coping, and well-being and developed a model of medical student coping termed the "coping reservoir." Results: The reservoir can be replenished or drained by various aspects of…

  7. Bayesian Analysis for Risk Assessment of Selected Medical Events in Support of the Integrated Medical Model Effort

    NASA Technical Reports Server (NTRS)

    Gilkey, Kelly M.; Myers, Jerry G.; McRae, Michael P.; Griffin, Elise A.; Kallrui, Aditya S.

    2012-01-01

    The Exploration Medical Capability project is creating a catalog of risk assessments using the Integrated Medical Model (IMM). The IMM is a software-based system intended to assist mission planners in preparing for spaceflight missions by helping them to make informed decisions about medical preparations and supplies needed for combating and treating various medical events using Probabilistic Risk Assessment. The objective is to use statistical analyses to inform the IMM decision tool with estimated probabilities of medical events occurring during an exploration mission. Because data regarding astronaut health are limited, Bayesian statistical analysis is used. Bayesian inference combines prior knowledge, such as data from the general U.S. population, the U.S. Submarine Force, or the analog astronaut population located at the NASA Johnson Space Center, with observed data for the medical condition of interest. The posterior results reflect the best evidence for specific medical events occurring in flight. Bayes theorem provides a formal mechanism for combining available observed data with data from similar studies to support the quantification process. The IMM team performed Bayesian updates on the following medical events: angina, appendicitis, atrial fibrillation, atrial flutter, dental abscess, dental caries, dental periodontal disease, gallstone disease, herpes zoster, renal stones, seizure, and stroke.

  8. Chromosome Conformation of Human Fibroblasts Grown in 3-Dimensional Spheroids

    PubMed Central

    Chen, Haiming; Comment, Nicholas; Chen, Jie; Ronquist, Scott; Hero, Alfred; Ried, Thomas; Rajapakse, Indika

    2015-01-01

    In the study of interphase chromosome organization, genome-wide chromosome conformation capture (Hi-C) maps are often generated using 2-dimensional (2D) monolayer cultures. These 2D cells have morphological deviations from cells that exist in 3-dimensional (3D) tissues in vivo, and may not maintain the same chromosome conformation. We used Hi-C maps to test the extent of differences in chromosome conformation between human fibroblasts grown in 2D cultures and those grown in 3D spheroids. Significant differences in chromosome conformation were found between 2D cells and those grown in spheroids. Intra-chromosomal interactions were generally increased in spheroid cells, with a few exceptions, while inter-chromosomal interactions were generally decreased. Overall, chromosomes located closer to the nuclear periphery had increased intra-chromosomal contacts in spheroid cells, while those located more centrally had decreased interactions. This study highlights the necessity to conduct studies on the topography of the interphase nucleus under conditions that mimic an in vivo environment. PMID:25738643

  9. Thermal crosstalk in 3-dimensional RRAM crossbar array

    PubMed Central

    Sun, Pengxiao; Lu, Nianduan; Li, Ling; Li, Yingtao; Wang, Hong; Lv, Hangbing; Liu, Qi; Long, Shibing; Liu, Su; Liu, Ming

    2015-01-01

    High density 3-dimensional (3D) crossbar resistive random access memory (RRAM) is one of the major focus of the new age technologies. To compete with the ultra-high density NAND and NOR memories, understanding of reliability mechanisms and scaling potential of 3D RRAM crossbar array is needed. Thermal crosstalk is one of the most critical effects that should be considered in 3D crossbar array application. The Joule heat generated inside the RRAM device will determine the switching behavior itself, and for dense memory arrays, the temperature surrounding may lead to a consequent resistance degradation of neighboring devices. In this work, thermal crosstalk effect and scaling potential under thermal effect in 3D RRAM crossbar array are systematically investigated. It is revealed that the reset process is dominated by transient thermal effect in 3D RRAM array. More importantly, thermal crosstalk phenomena could deteriorate device retention performance and even lead to data storage state failure from LRS (low resistance state) to HRS (high resistance state) of the disturbed RRAM cell. In addition, the resistance state degradation will be more serious with continuously scaling down the feature size. Possible methods for alleviating thermal crosstalk effect while further advancing the scaling potential are also provided and verified by numerical simulation. PMID:26310537

  10. Thermal crosstalk in 3-dimensional RRAM crossbar array.

    PubMed

    Sun, Pengxiao; Lu, Nianduan; Li, Ling; Li, Yingtao; Wang, Hong; Lv, Hangbing; Liu, Qi; Long, Shibing; Liu, Su; Liu, Ming

    2015-01-01

    High density 3-dimensional (3D) crossbar resistive random access memory (RRAM) is one of the major focus of the new age technologies. To compete with the ultra-high density NAND and NOR memories, understanding of reliability mechanisms and scaling potential of 3D RRAM crossbar array is needed. Thermal crosstalk is one of the most critical effects that should be considered in 3D crossbar array application. The Joule heat generated inside the RRAM device will determine the switching behavior itself, and for dense memory arrays, the temperature surrounding may lead to a consequent resistance degradation of neighboring devices. In this work, thermal crosstalk effect and scaling potential under thermal effect in 3D RRAM crossbar array are systematically investigated. It is revealed that the reset process is dominated by transient thermal effect in 3D RRAM array. More importantly, thermal crosstalk phenomena could deteriorate device retention performance and even lead to data storage state failure from LRS (low resistance state) to HRS (high resistance state) of the disturbed RRAM cell. In addition, the resistance state degradation will be more serious with continuously scaling down the feature size. Possible methods for alleviating thermal crosstalk effect while further advancing the scaling potential are also provided and verified by numerical simulation. PMID:26310537

  11. Probabilistic predictive modelling of carbon nanocomposites for medical implants design.

    PubMed

    Chua, Matthew; Chui, Chee-Kong

    2015-04-01

    Modelling of the mechanical properties of carbon nanocomposites based on input variables like percentage weight of Carbon Nanotubes (CNT) inclusions is important for the design of medical implants and other structural scaffolds. Current constitutive models for the mechanical properties of nanocomposites may not predict well due to differences in conditions, fabrication techniques and inconsistencies in reagents properties used across industries and laboratories. Furthermore, the mechanical properties of the designed products are not deterministic, but exist as a probabilistic range. A predictive model based on a modified probabilistic surface response algorithm is proposed in this paper to address this issue. Tensile testing of three groups of different CNT weight fractions of carbon nanocomposite samples displays scattered stress-strain curves, with the instantaneous stresses assumed to vary according to a normal distribution at a specific strain. From the probabilistic density function of the experimental data, a two factors Central Composite Design (CCD) experimental matrix based on strain and CNT weight fraction input with their corresponding stress distribution was established. Monte Carlo simulation was carried out on this design matrix to generate a predictive probabilistic polynomial equation. The equation and method was subsequently validated with more tensile experiments and Finite Element (FE) studies. The method was subsequently demonstrated in the design of an artificial tracheal implant. Our algorithm provides an effective way to accurately model the mechanical properties in implants of various compositions based on experimental data of samples. PMID:25658876

  12. Simulation and optimization models for emergency medical systems planning.

    PubMed

    Bettinelli, Andrea; Cordone, Roberto; Ficarelli, Federico; Righini, Giovanni

    2014-01-01

    The authors address strategic planning problems for emergency medical systems (EMS). In particular, the three following critical decisions are considered: i) how many ambulances to deploy in a given territory at any given point in time, to meet the forecasted demand, yielding an appropriate response time; ii) when ambulances should be used for serving nonurgent requests and when they should better be kept idle for possible incoming urgent requests; iii) how to define an optimal mix of contracts for renting ambulances from private associations to meet the forecasted demand at minimum cost. In particular, analytical models for decision support, based on queuing theory, discrete-event simulation, and integer linear programming were presented. Computational experiments have been done on real data from the city of Milan, Italy. PMID:25069023

  13. Genetically engineered livestock: ethical use for food and medical models.

    PubMed

    Garas, Lydia C; Murray, James D; Maga, Elizabeth A

    2015-01-01

    Recent advances in the production of genetically engineered (GE) livestock have resulted in a variety of new transgenic animals with desirable production and composition changes. GE animals have been generated to improve growth efficiency, food composition, and disease resistance in domesticated livestock species. GE animals are also used to produce pharmaceuticals and as medical models for human diseases. The potential use of these food animals for human consumption has prompted an intense debate about food safety and animal welfare concerns with the GE approach. Additionally, public perception and ethical concerns about their use have caused delays in establishing a clear and efficient regulatory approval process. Ethically, there are far-reaching implications of not using genetically engineered livestock, at a detriment to both producers and consumers, as use of this technology can improve both human and animal health and welfare. PMID:25387117

  14. Expanding the Biomedical Model: Case Studies of Five Medical Schools.

    ERIC Educational Resources Information Center

    Tresolini, Carol P.; And Others

    This study examined five representative medical schools for approaches to teaching integrated approaches to health care. Traditionally medical schools have taught from a biomedical, technological approach. The study used a qualitative, multiple case study design to explore which medical schools were attempting integrated health care education. On…

  15. Students Teaching Students: A Model for Medical Education

    ERIC Educational Resources Information Center

    Flax, Jim; Garrard, Judith

    1974-01-01

    At the University of Minnesota Medical School a course, Introduction to Clinical Medicine, introduces communication skills; develops interview skills consistent with students' personality, their role as medical students, and the patients' needs; assists students in becoming comfortable as medical students in the hospital setting; and teaches them…

  16. 3 Dimensional Diagnosis Unravelling Prognosis of Multiple Impacted Teeth – A Case Report

    PubMed Central

    Gopinath, Adusumilli; Reddy, Naveen Admala; Rohra, Mayur G

    2013-01-01

    Impaction of teeth results from the interplay between nature and nurture. Radiographs play an important role in assessment of both the location and the typing of impacted teeth. In general, periapical, occlusal, and/or panoramic radiographs are sufficient for providing the information required by the clinician. Recent advances in diagnostic imaging enables to visualize , diagnose and prognose the treatment outcome of the impacted teeth. This case report discusses the value of cone beam computerized tomography (CBCT) for evaluation of the critical parameters like bone thickness , tooth position and tooth morphology of multiple impacted teeth by 3 dimensional radiography – CBCT. In this report, we present a case of 27-year-old male patient with multiple missing teeth. Radiographs revealed multiple impacted permanent teeth, though medical and family history along with physical examination was not suggestive of any syndromes. Intraoral periapical radiograph, Orthopantomograph, Occlusal radiograph, Cone beam computed tomography were taken for the same patient to determine the exact position of multiple impacted teeth and prognose the treatment plan with the associated factors to impacted teeth. Cone beam computed tomography is an accurate modality to localize and determine the prognosing factors associated with multiple impacted teeth. Three-dimensional volumetric imaging might provide information for improved diagnosis and treatment plans, and ultimately result in more successful treatment outcomes and better care for patients. How to cite this article: Gopinath A, Reddy NA, Rohra MG. 3 Dimensional Diagnosis Unravelling Prognosis of Multiple Impacted Teeth – A Case Report. J Int Oral Health 2013; 5(4):78-83. PMID:24155625

  17. Animal Models for Medical Countermeasures to Radiation Exposure

    PubMed Central

    Williams, Jacqueline P.; Brown, Stephen L.; Georges, George E.; Hauer-Jensen, Martin; Hill, Richard P.; Huser, Amy K.; Kirsch, David G.; MacVittie, Thomas J.; Mason, Kathy A.; Medhora, Meetha M.; Moulder, John E.; Okunieff, Paul; Otterson, Mary F.; Robbins, Michael E.; Smathers, James B.; McBride, William H.

    2011-01-01

    Since September 11, 2001, there has been the recognition of a plausible threat from acts of terrorism, including radiological or nuclear attacks. A network of Centers for Medical Countermeasures against Radiation (CMCRs) has been established across the U.S.; one of the missions of this network is to identify and develop mitigating agents that can be used to treat the civilian population after a radiological event. The development of such agents requires comparison of data from many sources and accumulation of information consistent with the “Animal Rule” from the Food and Drug Administration (FDA). Given the necessity for a consensus on appropriate animal model use across the network to allow for comparative studies to be performed across institutions, and to identify pivotal studies and facilitate FDA approval, in early 2008, investigators from each of the CMCRs organized and met for an Animal Models Workshop. Working groups deliberated and discussed the wide range of animal models available for assessing agent efficacy in a number of relevant tissues and organs, including the immune and hematopoietic systems, gastrointestinal tract, lung, kidney and skin. Discussions covered the most appropriate species and strains available as well as other factors that may affect differential findings between groups and institutions. This report provides the workshop findings. PMID:20334528

  18. [Independent medical processing enterprises as innovative organizational model for market of medical services].

    PubMed

    Shevchenko, Iu L; Matveev, S A; Makhnev, D A; Korsun, K Iu

    2006-01-01

    In Russia, current stage of health care development is characterized by occurrence of various problems. Most of them are related to cooperation between participators of market of medical services. Different options are proposed to resolve cooperation problems embedded into medical services market with emphasis on development of ultimately different medical processing enterprise with brand-new organizational and functional structure. Its functioning is based on process management logistics. The company broad professional experience allows to implement above-mentioned managerial structure and make it function as well as claims positive perspectives of described option. PMID:16739625

  19. Video Based Sensor for Tracking 3-Dimensional Targets

    NASA Technical Reports Server (NTRS)

    Howard, R. T.; Book, Michael L.; Bryan, Thomas C.

    2000-01-01

    Video-Based Sensor for Tracking 3-Dimensional Targets The National Aeronautics and Space Administration's (NASAs) Marshall Space Flight Center (MSFC) has been developing and testing video-based sensors for automated spacecraft guidance for several years, and the next generation of video sensor will have tracking rates up to 100 Hz and will be able to track multiple reflectors and targets. The Video Guidance Sensor (VGS) developed over the past several years has performed well in testing and met the objective of being used as the terminal guidance sensor for an automated rendezvous and capture system. The first VGS was successfully tested in closed-loop 3-degree-of-freedom (3- DOF) tests in 1989 and then in 6-DOF open-loop tests in 1992 and closed-loop tests in 1993-4. Development and testing continued, and in 1995 approval was given to test the VGS in an experiment on the Space Shuttle. The VGS flew in 1997 and in 1998, performing well for both flights. During the development and testing before, during, and after the flight experiments, numerous areas for improvement were found. The VGS was developed with a sensor head and an electronics box, connected by cables. The VGS was used in conjunction with a target that had wavelength-filtered retro-reflectors in a specific pattern, The sensor head contained the laser diodes, video camera, and heaters and coolers. The electronics box contained a frame grabber, image processor, the electronics to control the components in the sensor head, the communications electronics, and the power supply. The system works by sequentially firing two different wavelengths of laser diodes at the target and processing the two images. Since the target only reflects one wavelength, it shows up well in one image and not at all in the other. Because the target's dimensions are known, the relative positions and attitudes of the target and the sensor can be computed from the spots reflected from the target. The system was designed to work from I

  20. Tracking Error analysis of Concentrator Photovoltaic Module Using Total 3-Dimensional Simulator

    NASA Astrophysics Data System (ADS)

    Ota, Yasuyuki; Nishioka, Kensuke

    2011-12-01

    A 3-dimensional (3D) operating simulator for concentrator photovoltaic (CPV) module using triple-junction solar cell was developed. By connecting 3D equivalent circuit simulation for triple-junction solar cell and ray-trace simulation for optics model, the operating characteristics of CPV module were calculated. A typical flat Fresnel lens and homogenizer were adapted to the optics model. The influence of tracking error on the performance of CPV module was calculated. There was the correlation between the optical efficiency and Isc. However, Pm was not correlated with these values, and was strongly dependent on FF. We can use this total simulator for the evaluation and optimization from the light incidence to operating characteristic of CPV modules.

  1. Use of 3-Dimensional Printing for Preoperative Planning in the Treatment of Recurrent Anterior Shoulder Instability

    PubMed Central

    Sheth, Ujash; Theodoropoulos, John; Abouali, Jihad

    2015-01-01

    Recurrent anterior shoulder instability often results from large bony Bankart or Hill-Sachs lesions. Preoperative imaging is essential in guiding our surgical management of patients with these conditions. However, we are often limited to making an attempt to interpret a 3-dimensional (3D) structure using conventional 2-dimensional imaging. In cases in which complex anatomy or bony defects are encountered, this type of imaging is often inadequate. We used 3D printing to produce a solid 3D model of a glenohumeral joint from a young patient with recurrent anterior shoulder instability and complex Bankart and Hill-Sachs lesions. The 3D model from our patient was used in the preoperative planning stages of an arthroscopic Bankart repair and remplissage to determine the depth of the Hill-Sachs lesion and the degree of abduction and external rotation at which the Hill-Sachs lesion engaged. PMID:26759768

  2. The Integrated Medical Model - A Risk Assessment and Decision Support Tool for Human Space Flight Missions

    NASA Technical Reports Server (NTRS)

    Kerstman, Eric; Minard, Charles G.; Saile, Lynn; FreiredeCarvalho, Mary; Myers, Jerry; Walton, Marlei; Butler, Douglas; Lopez, Vilma

    2010-01-01

    The Integrated Medical Model (IMM) is a decision support tool that is useful to space flight mission planners and medical system designers in assessing risks and optimizing medical systems. The IMM employs an evidence-based, probabilistic risk assessment (PRA) approach within the operational constraints of space flight.

  3. A Latent Growth Model Suggests that Empathy of Medical Students Does Not Decline over Time

    ERIC Educational Resources Information Center

    Costa, Patrício; Magalhães, Eunice; Costa, Manuel João

    2013-01-01

    Empathy is a relevant attribute in the context of patient care. However, a decline in empathy throughout medical education has been reported in North-American medical schools, particularly, in the transition to clinical training. The present study aims to longitudinally model empathy during medical school at three time points: at the entrance,…

  4. Replication of a Multidimensional Model of Medical School Similarities. Final Report.

    ERIC Educational Resources Information Center

    Sherman, Charles R.

    In 1976, the Association of American Medical Colleges developed a map-like model to describe the global picture of the U.S. medical school similarities with respect to two loosely defined concepts: an institutional emphasis on research and an emphasis on clinical and graduate medical training. This study is an attempt to replicate the results of…

  5. Social Work Education on Mental Health: Postmodern Discourse and the Medical Model

    ERIC Educational Resources Information Center

    Casstevens, W. J.

    2010-01-01

    This article provides a pedagogical approach to presenting alternatives along with the traditional medical model in the context of mental health treatment and service provision. Given the current influence of the medical model in community mental health, this article outlines a rationale for challenging the model and considering alternative models…

  6. Expanding the Biomedical Model: Interviews with Medical Educators.

    ERIC Educational Resources Information Center

    Tresolini, Carol P.; Shugars, Daniel A.

    A study was done to broaden the understanding of how medical school programs can integrate the biomedical and psychosocial domains and to gather information for curriculum and program development and evaluation. The study used an exploratory, qualitative research approach and collected data through interviews with 22 expert medical faculty and…

  7. Addiction medicine: a model osteopathic medical school curriculum.

    PubMed

    Lande, R Gregory; Wyatt, Stephen A; Przekop, Peter R

    2010-03-01

    The World Health Organization has identified nicotine, alcohol, and illicit drugs as among the top 10 contributors of morbidity and mortality in the world. Substance use disorders are preventable conditions that are major contributors to poor health, family dysfunction, and various social problems in the United States-problems that have a profound economic impact. The American Osteopathic Academy of Addiction Medicine seeks to promote teaching of addiction medicine at colleges of osteopathic medicine (COMs), which-honoring the osteopathic concepts of holistic medicine and disease prevention-are well poised to develop a model addiction medicine curriculum. Educators and students at COMs can use guidelines from Project MAINSTREAM, a core addiction medicine curriculum designed to improve education of health professionals in substance abuse, for developing addiction medicine curricula and for gauging their professional growth. These guidelines should be incorporated into the first 2 years of osteopathic medical students' basic science didactics. The authors encourage the development of addiction medicine courses and curricula at all COMs. PMID:20386021

  8. Automated medical diagnosis with fuzzy stochastic models: monitoring chronic diseases.

    PubMed

    Jeanpierre, Laurent; Charpillet, François

    2004-01-01

    As the world population ages, the patients per physician ratio keeps on increasing. This is even more important in the domain of chronic pathologies where people are usually monitored for years and need regular consultations. To address this problem, we propose an automated system to monitor a patient population, detecting anomalies in instantaneous data and in their temporal evolution, so that it could alert physicians. By handling the population of healthy patients autonomously and by drawing the physicians' attention to the patients-at-risk, the system allows physicians to spend comparatively more time with patients who need their services. In such a system, the interaction between the patients, the diagnosis module, and the physicians is very important. We have based this system on a combination of stochastic models, fuzzy filters, and strong medical semantics. We particularly focused on a particular tele-medicine application: the Diatelic Project. Its objective is to monitor chronic kidney-insufficient patients and to detect hydration troubles. During two years, physicians from the ALTIR have conducted a prospective randomized study of the system. This experiment clearly shows that the proposed system is really beneficial to the patients' health. PMID:15520535

  9. Live streaming video for medical education: a laboratory model.

    PubMed

    Gandsas, Alejandro; McIntire, Katherine; Palli, Guillermo; Park, Adrian

    2002-10-01

    At the University of Kentucky (UK), we applied streaming video technology to develop a webcast model that will allow institutions to broadcast live and prerecorded surgeries, conferences, and courses in real time over networks (the Internet or an intranet). We successfully broadcast a prerecorded laparoscopic paraesophageal hernia repair to domestic and international clients by using desktop computers equipped with off-the-shelf, streaming-enabled software and standard hardware and operating systems. A web-based user interface made accessing the educational material as simple as a mouse click and allowed clients to participate in the broadcast event via an embedded e-mail/chat module. Three client computers (two connected to the Internet and a third connected to the UK intranet) requested and displayed the surgical film by means of seven common network connection configurations. Significantly, no difference in image resolution was detected with the use of a connection speed faster than 128 kilobytes per second (kbps). At this connection speed, an average bandwidth of 32.7 kbps was used, and although a 15-second delay was experienced from the time of data request to data display, the surgical film streamed continuously from beginning to end at a mean rate of 14.4 frames per second (fps). The clients easily identified all anatomic structures in full color motion, clearly followed all steps of the surgical procedure, and successfully asked questions and made comments by using the e-mail/chat module while viewing the surgery. With minimal financial investment, we have created an interactive virtual classroom with the potential to attract a global audience. Our webcast model represents a simple and practical method for institutions to supplement undergraduate and graduate surgical education and offer continuing medical education credits in a way that is convenient for clients (surgeons, students, residents, others). In the future, physicians may access streaming webcast

  10. Physical Constraint Finite Element Model for Medical Image Registration

    PubMed Central

    Zhang, Jingya; Wang, Jiajun; Wang, Xiuying; Gao, Xin; Feng, Dagan

    2015-01-01

    Due to being derived from linear assumption, most elastic body based non-rigid image registration algorithms are facing challenges for soft tissues with complex nonlinear behavior and with large deformations. To take into account the geometric nonlinearity of soft tissues, we propose a registration algorithm on the basis of Newtonian differential equation. The material behavior of soft tissues is modeled as St. Venant-Kirchhoff elasticity, and the nonlinearity of the continuum represents the quadratic term of the deformation gradient under the Green- St.Venant strain. In our algorithm, the elastic force is formulated as the derivative of the deformation energy with respect to the nodal displacement vectors of the finite element; the external force is determined by the registration similarity gradient flow which drives the floating image deforming to the equilibrium condition. We compared our approach to three other models: 1) the conventional linear elastic finite element model (FEM); 2) the dynamic elastic FEM; 3) the robust block matching (RBM) method. The registration accuracy was measured using three similarities: MSD (Mean Square Difference), NC (Normalized Correlation) and NMI (Normalized Mutual Information), and was also measured using the mean and max distance between the ground seeds and corresponding ones after registration. We validated our method on 60 image pairs including 30 medical image pairs with artificial deformation and 30 clinical image pairs for both the chest chemotherapy treatment in different periods and brain MRI normalization. Our method achieved a distance error of 0.320±0.138 mm in x direction and 0.326±0.111 mm in y direction, MSD of 41.96±13.74, NC of 0.9958±0.0019, NMI of 1.2962±0.0114 for images with large artificial deformations; and average NC of 0.9622±0.008 and NMI of 1.2764±0.0089 for the real clinical cases. Student’s t-test demonstrated that our model statistically outperformed the other methods in comparison (p

  11. The approach of Bayesian model indicates media awareness of medical errors

    NASA Astrophysics Data System (ADS)

    Ravichandran, K.; Arulchelvan, S.

    2016-06-01

    This research study brings out the factors behind the increase in medical malpractices in the Indian subcontinent in the present day environment and impacts of television media awareness towards it. Increased media reporting of medical malpractices and errors lead to hospitals taking corrective action and improve the quality of medical services that they provide. The model of Cultivation Theory can be used to measure the influence of media in creating awareness of medical errors. The patient's perceptions of various errors rendered by the medical industry from different parts of India were taken up for this study. Bayesian method was used for data analysis and it gives absolute values to indicate satisfaction of the recommended values. To find out the impact of maintaining medical records of a family online by the family doctor in reducing medical malpractices which creates the importance of service quality in medical industry through the ICT.

  12. Continuing education for medical students: a library model

    PubMed Central

    Swanberg, Stephanie M.; Engwall, Keith; Mi, Misa

    2015-01-01

    Purpose The research assessed a three-year continuing medical education–style program for medical students in a Midwestern academic medical library. Methods A mixed methods approach of a survey and two focus groups comparing attendees versus non-attendees assessed the program. Results Eleven students participated in the focus groups. Attendance was driven by topic interest and lunch. Barriers included lack of interest, scheduling, location, and convenience. Conclusions Although attendance was a challenge, students valued opportunities to learn new skills. This study showcases a reproducible method to engage students outside the curriculum. PMID:26512222

  13. Accuracy of medical models made by consumer-grade fused deposition modelling printers

    PubMed Central

    Petropolis, Christian; Kozan, Daniel; Sigurdson, Leif

    2015-01-01

    BACKGROUND: Additive manufacturing using fused deposition modelling (FDM) has become widely available with the development of consumer-grade three-dimensional printers. To be useful in maxillofacial surgery, models created by these printers must accurately reproduce the craniofacial skeleton. OBJECTIVE: To determine the accuracy of consumer-grade FDM printers in the production of medical models compared with industrial selective laser sintering (SLS) printers. METHODS: Computed tomography images of a dry skull were manipulated using OsiriX (OsiriX, Switzerland) and ZBrush (Pixologic, USA) software. Models were fabricated using a consumer-grade FDM printer at 100 μm, 250 μm and 500 μm layer heights and an industrial SLS printer. Seven linear measurements were made on the models and compared with the corresponding dry skull measurements using an electronic caliper. RESULTS: A dimensional error of 0.30% was observed for the SLS models and 0.44%, 0.52% and 1.1% for the 100 μm, 250 μm and 500 μm FDM models, respectively. CONCLUSION: Consumer-grade FDM printers can produce medical models with sufficient dimensional accuracy for use in maxillofacial surgery. With this technology, surgeons can independently produce low-cost maxillofacial models in an office setting. PMID:26090349

  14. Method and apparatus for imaging through 3-dimensional tracking of protons

    NASA Technical Reports Server (NTRS)

    Ryan, James M. (Inventor); Macri, John R. (Inventor); McConnell, Mark L. (Inventor)

    2001-01-01

    A method and apparatus for creating density images of an object through the 3-dimensional tracking of protons that have passed through the object are provided. More specifically, the 3-dimensional tracking of the protons is accomplished by gathering and analyzing images of the ionization tracks of the protons in a closely packed stack of scintillating fibers.

  15. Ecological Psychology: Replacing the Medical Model Paradigm for School-Based Psychological and Psychoeducational Services

    ERIC Educational Resources Information Center

    Gutkin, Terry B.

    2012-01-01

    Traditional medical model service delivery systems have facilitated the creation of nationwide mental health and education pandemics for children and youth. The characteristics and shortcomings of medical model approaches leading to these problems are explicated, including the focus of services on individuals rather than populations, relying…

  16. It's All in Your Head: Feminist and Medical Models of Menopause (Strange Bedfellows).

    ERIC Educational Resources Information Center

    Posner, Judith

    1979-01-01

    This article describes the medical model of menopause as it exists in contemporary gynecological textbooks and some popular books written by gynecologists for the general public. The feminist position on menopause is then compared and contrasted with the medical model. (Author/EB)

  17. Generation and 3-Dimensional Quantitation of Arterial Lesions in Mice Using Optical Projection Tomography

    PubMed Central

    Kirkby, Nicholas S.; Low, Lucinda; Wu, Junxi; Miller, Eileen; Seckl, Jonathan R.; Walker, Brian R.; Webb, David J.; Hadoke, Patrick W. F.

    2015-01-01

    The generation and analysis of vascular lesions in appropriate animal models is a cornerstone of research into cardiovascular disease, generating important information on the pathogenesis of lesion formation and the action of novel therapies. Use of atherosclerosis-prone mice, surgical methods of lesion induction, and dietary modification has dramatically improved understanding of the mechanisms that contribute to disease development and the potential of new treatments. Classically, analysis of lesions is performed ex vivo using 2-dimensional histological techniques. This article describes application of optical projection tomography (OPT) to 3-dimensional quantitation of arterial lesions. As this technique is non-destructive, it can be used as an adjunct to standard histological and immunohistochemical analyses. Neointimal lesions were induced by wire-insertion or ligation of the mouse femoral artery whilst atherosclerotic lesions were generated by administration of an atherogenic diet to apoE-deficient mice. Lesions were examined using OPT imaging of autofluorescent emission followed by complementary histological and immunohistochemical analysis. OPT clearly distinguished lesions from the underlying vascular wall. Lesion size was calculated in 2-dimensional sections using planimetry, enabling calculation of lesion volume and maximal cross-sectional area. Data generated using OPT were consistent with measurements obtained using histology, confirming the accuracy of the technique and its potential as a complement (rather than alternative) to traditional methods of analysis. This work demonstrates the potential of OPT for imaging atherosclerotic and neointimal lesions. It provides a rapid, much needed ex vivo technique for the routine 3-dimensional quantification of vascular remodelling. PMID:26067588

  18. Modeling the acceptance of clinical information systems among hospital medical staff: an extended TAM model.

    PubMed

    Melas, Christos D; Zampetakis, Leonidas A; Dimopoulou, Anastasia; Moustakis, Vassilis

    2011-08-01

    Recent empirical research has utilized the Technology Acceptance Model (TAM) to advance the understanding of doctors' and nurses' technology acceptance in the workplace. However, the majority of the reported studies are either qualitative in nature or use small convenience samples of medical staff. Additionally, in very few studies moderators are either used or assessed despite their importance in TAM based research. The present study focuses on the application of TAM in order to explain the intention to use clinical information systems, in a random sample of 604 medical staff (534 physicians) working in 14 hospitals in Greece. We introduce physicians' specialty as a moderator in TAM and test medical staff's information and communication technology (ICT) knowledge and ICT feature demands, as external variables. The results show that TAM predicts a substantial proportion of the intention to use clinical information systems. Findings make a contribution to the literature by replicating, explaining and advancing the TAM, whereas theory is benefited by the addition of external variables and medical specialty as a moderator. Recommendations for further research are discussed. PMID:21292029

  19. Evaluating an interprofessional disease state and medication management review model.

    PubMed

    Hoti, Kreshnik; Forman, Dawn; Hughes, Jeffery

    2014-03-01

    There is lack of literature data reporting an incorporation of medication management reviews in students' interprofessional education (IPE) and practice programs in aged care settings. This pilot study reports how an interprofessional disease state and medication management review program (DSMMR) was established in a residential aged care facility in Perth, Western Australia. Students from the professions of nursing, pharmacy and physiotherapy focused on a wellness check in the areas of cognition, falls and continence while integrating a medication management review. Students' attitudes were explored using a pre- and post-placement questionnaire. Students indicated positive experience with the IPE DSMMR program which also resulted in their positive attitudinal shift towards IPE and practice. These findings indicated that aged care can be a suitable setting for student interprofessional programs focusing on DSMMR. PMID:24246025

  20. Unification of color postprocessing techniques for 3-dimensional computational mechanics

    NASA Technical Reports Server (NTRS)

    Bailey, Bruce Charles

    1985-01-01

    To facilitate the understanding of complex three-dimensional numerical models, advanced interactive color postprocessing techniques are introduced. These techniques are sufficiently flexible so that postprocessing difficulties arising from model size, geometric complexity, response variation, and analysis type can be adequately overcome. Finite element, finite difference, and boundary element models may be evaluated with the prototype postprocessor. Elements may be removed from parent models to be studied as independent subobjects. Discontinuous responses may be contoured including responses which become singular, and nonlinear color scales may be input by the user for the enhancement of the contouring operation. Hit testing can be performed to extract precise geometric, response, mesh, or material information from the database. In addition, stress intensity factors may be contoured along the crack front of a fracture model. Stepwise analyses can be studied, and the user can recontour responses repeatedly, as if he were paging through the response sets. As a system, these tools allow effective interpretation of complex analysis results.

  1. A Dual Hesitant Fuzzy Multigranulation Rough Set over Two-Universe Model for Medical Diagnoses.

    PubMed

    Zhang, Chao; Li, Deyu; Yan, Yan

    2015-01-01

    In medical science, disease diagnosis is one of the difficult tasks for medical experts who are confronted with challenges in dealing with a lot of uncertain medical information. And different medical experts might express their own thought about the medical knowledge base which slightly differs from other medical experts. Thus, to solve the problems of uncertain data analysis and group decision making in disease diagnoses, we propose a new rough set model called dual hesitant fuzzy multigranulation rough set over two universes by combining the dual hesitant fuzzy set and multigranulation rough set theories. In the framework of our study, both the definition and some basic properties of the proposed model are presented. Finally, we give a general approach which is applied to a decision making problem in disease diagnoses, and the effectiveness of the approach is demonstrated by a numerical example. PMID:26858772

  2. A Dual Hesitant Fuzzy Multigranulation Rough Set over Two-Universe Model for Medical Diagnoses

    PubMed Central

    Zhang, Chao; Li, Deyu; Yan, Yan

    2015-01-01

    In medical science, disease diagnosis is one of the difficult tasks for medical experts who are confronted with challenges in dealing with a lot of uncertain medical information. And different medical experts might express their own thought about the medical knowledge base which slightly differs from other medical experts. Thus, to solve the problems of uncertain data analysis and group decision making in disease diagnoses, we propose a new rough set model called dual hesitant fuzzy multigranulation rough set over two universes by combining the dual hesitant fuzzy set and multigranulation rough set theories. In the framework of our study, both the definition and some basic properties of the proposed model are presented. Finally, we give a general approach which is applied to a decision making problem in disease diagnoses, and the effectiveness of the approach is demonstrated by a numerical example. PMID:26858772

  3. Using Medical History Embedded in Biometrics Medical Card for User Identity Authentication: Privacy Preserving Authentication Model by Features Matching

    PubMed Central

    Fong, Simon; Zhuang, Yan

    2012-01-01

    Many forms of biometrics have been proposed and studied for biometrics authentication. Recently researchers are looking into longitudinal pattern matching that based on more than just a singular biometrics; data from user's activities are used to characterise the identity of a user. In this paper we advocate a novel type of authentication by using a user's medical history which can be electronically stored in a biometric security card. This is a sequel paper from our previous work about defining abstract format of medical data to be queried and tested upon authentication. The challenge to overcome is preserving the user's privacy by choosing only the useful features from the medical data for use in authentication. The features should contain less sensitive elements and they are implicitly related to the target illness. Therefore exchanging questions and answers about a few carefully chosen features in an open channel would not easily or directly expose the illness, but yet it can verify by inference whether the user has a record of it stored in his smart card. The design of a privacy preserving model by backward inference is introduced in this paper. Some live medical data are used in experiments for validation and demonstration. PMID:22550398

  4. Using medical history embedded in biometrics medical card for user identity authentication: privacy preserving authentication model by features matching.

    PubMed

    Fong, Simon; Zhuang, Yan

    2012-01-01

    Many forms of biometrics have been proposed and studied for biometrics authentication. Recently researchers are looking into longitudinal pattern matching that based on more than just a singular biometrics; data from user's activities are used to characterise the identity of a user. In this paper we advocate a novel type of authentication by using a user's medical history which can be electronically stored in a biometric security card. This is a sequel paper from our previous work about defining abstract format of medical data to be queried and tested upon authentication. The challenge to overcome is preserving the user's privacy by choosing only the useful features from the medical data for use in authentication. The features should contain less sensitive elements and they are implicitly related to the target illness. Therefore exchanging questions and answers about a few carefully chosen features in an open channel would not easily or directly expose the illness, but yet it can verify by inference whether the user has a record of it stored in his smart card. The design of a privacy preserving model by backward inference is introduced in this paper. Some live medical data are used in experiments for validation and demonstration. PMID:22550398

  5. Biomechanical 3-Dimensional Finite Element Analysis of Obturator Protheses Retained with Zygomatic and Dental Implants in Maxillary Defects

    PubMed Central

    Akay, Canan; Yaluğ, Suat

    2015-01-01

    Background The objective of this study was to investigate the stress distribution in the bone around zygomatic and dental implants for 3 different implant-retained obturator prostheses designs in a Aramany class IV maxillary defect using 3-dimensional finite element analysis (FEA). Material\\Methods A 3-dimensional finite element model of an Aramany class IV defect was created. Three different implant-retained obturator prostheses were modeled: model 1 with 1 zygomatic implant and 1 dental implant, model 2 with 1 zygomatic implant and 2 dental implants, and model 3 with 2 zygomatic implants. Locator attachments were used as a superstructure. A 150-N load was applied 3 different ways. Qualitative analysis was based on the scale of maximum principal stress; values obtained through quantitative analysis are expressed in MPa. Results In all loading conditions, model 3 (when compared models 1 and 2) showed the lowest maximum principal stress value. Model 3 is the most appropirate reconstruction in Aramany class IV maxillary defects. Two zygomatic implants can reduce the stresses in model 3. The distribution of stresses on prostheses were more rational with the help of zygoma implants, which can distribute the stresses on each part of the maxilla. Conclusions Aramany class IV obturator prosthesis placement of 2 zygomatic implants in each side of the maxilla is more advantageous than placement of dental implants. In the non-defective side, increasing the number of dental implants is not as suitable as zygomatic implants. PMID:25714086

  6. The Medical Model Revisited. A Point of View.

    ERIC Educational Resources Information Center

    Beange, Helen

    1986-01-01

    The medical evaluation of 165 mentally retarded Australian adults found an average of 2.6 health problems, well above the number in the general population. In order of frequency, conditions found included obesity, ocular impairment, serious dental problems, and aural disorders. Active health promotion with this group is recommended. (DB)

  7. A Model for Peer Tutoring in the Medical School Setting.

    ERIC Educational Resources Information Center

    Walker-Bartnick, Leslie A.; And Others

    1984-01-01

    A program providing successful peer tutoring in nine of 10 basic science courses in the first two years of medical school is described, and the management of such a program is discussed. Positive program effects on both tutors and students in academic difficulty are emphasized. (MSE)

  8. The Medical Model and the Preparation of Education Professionals.

    ERIC Educational Resources Information Center

    Grady, Marilyn L.

    1993-01-01

    By reviewing the training of medical professionals, one can identify similarities to the preparation of education professionals (teachers). On a basic level, the medicine and education fields are both practice-oriented; require individuals with problem-solving, decision-making, and interpersonal skills; depend on information bases that multiply…

  9. An Evaluation Model for Professional Education--Medical Education.

    ERIC Educational Resources Information Center

    McGuire, Christine H.

    There are striking similarities between medical education of today and progressive education of the thirties with respect to motivation for change, the values to be sought in change, and the zest with which change is pursued. It is in this climate conducive to change that a new approach to evaluation is beginning to make a significant contribution…

  10. Evaluating Medical Students' Patient Interviewing Skills: A Biopsychosocial Model.

    ERIC Educational Resources Information Center

    Calhoun, Judith G.; And Others

    1987-01-01

    An evaluation design project was undertaken to design a cost effective, standardized method for assessing the instructional effectiveness of the changes and outcomes associated with a pilot curriculum project focusing on the importance of the medical history in clinical problem solving. (LMO)

  11. Computer-assisted 3-dimensional anthropometry of the scaphoid.

    PubMed

    Pichler, Wolfgang; Windisch, Gunther; Schaffler, Gottfried; Heidari, Nima; Dorr, Katrin; Grechenig, Wolfgang

    2010-02-01

    Scaphoid fracture fixation using a cannulated headless compression screw and the Matti-Russe procedure for the treatment of scaphoid nonunions are performed routinely. Surgeons performing these procedures need to be familiar with the anatomy of the scaphoid. A literature review reveals relatively few articles on this subject. The goal of this anatomical study was to measure the scaphoid using current technology and to discuss the findings with respect to the current, relevant literature.Computed tomography scans of 30 wrists were performed using a 64-slice SOMATOM Sensation CT system (resolution 0.6 mm) (Siemens Medical Solutions Inc, Malvern, Pennsylvania). Three-dimensional reconstructions from the raw data were generated by MIMICS software (Materialise, Leuven, Belgium). The scaphoid had a mean length of 26.0 mm (range, 22.3-30.7 mm), and men had a significantly longer (P<.001) scaphoid than women (27.861.6 mm vs 24.561.6 mm, respectively). The width and height were measured at 3 different levels for volume calculations, resulting in a mean volume of 3389.5 mm(3). Men had a significantly larger (P<.001) scaphoid volume than women (4057.86740.7 mm(3) vs 2846.56617.5 mm(3), respectively).We found considerable variation in the length and volume of the scaphoid in our cohort. We also demonstrated a clear correlation between scaphoid size and sex. Surgeons performing operative fixation of scaphoid fractures and corticocancellous bone grafting for nonunions need to be familiar with these anatomical variations. PMID:20192143

  12. Description of a practice model for pharmacist medication review in a general practice setting

    PubMed Central

    Brandt, Mette; Hallas, Jesper; Graabæk, Trine; Pottegård, Anton

    2014-01-01

    Background Practical descriptions of procedures used for pharmacists’ medication reviews are sparse. Objective To describe a model for medication review by pharmacists tailored to a general practice setting. Methods A stepwise model is described. The model is based on data from the medical chart and clinical or laboratory data. The medication review focuses on the diagnoses of the patient instead of the individual drugs. Patient interviews are not part of the model. The model was tested in a pilot study by conducting medical reviews on 50 polypharmacy patients (i.e. receiving 7 or more drugs for regular use). Results The model contained seven main steps. Information about the patient and current treatment was collected in the first three steps, followed by identification of possible interventions related to either diagnoses or drugs in the fourth and fifth step. The sixth and seventh step concerned the reporting of interventions and the considerations of the GPs. 208 interventions were proposed among the 50 patients. The acceptance rate among the GPs was 82%. The most common interventions were lack of clinical or laboratory data (n=57, 27%) and drugs that should be discontinued as they had no indication (n=47, 23%). Most interventions were aimed at cardiovascular drugs. Conclusion We have provided a detailed description of a practical approach to pharmacists’ medication review in a GP setting. The model was tested and found to be usable, and to deliver a medication review with high acceptance rates. PMID:25243030

  13. Medication errors in the intensive care unit: literature review using the SEIPS model.

    PubMed

    Frith, Karen H

    2013-01-01

    Medication errors in intensive care units put patients at risk for injury or death every day. Safety requires an organized and systematic approach to improving the tasks, technology, environment, and organizational culture associated with medication systems. The Systems Engineering Initiative for Patient Safety model can help leaders and health care providers understand the complicated and high-risk work associated with critical care. Using this model, the author combines a human factors approach with the well-known structure-process-outcome model of quality improvement to examine research literature. The literature review reveals that human factors, including stress, high workloads, knowledge deficits, and performance deficits, are associated with medication errors. Factors contributing to medication errors are frequent interruptions, communication problems, and poor fit of health information technology to the workflow of providers. Multifaceted medication safety interventions are needed so that human factors and system problems can be addressed simultaneously. PMID:24153217

  14. 3-dimensional wells and tunnels for finite element grids

    SciTech Connect

    Cherry, T.A.; Gable, C.W.; Trease, H.

    1996-12-31

    Modeling fluid, vapor, and air injection and extraction from wells poses a number of problems. The length scale of well bores is centimeters, the region of high pressure gradient may be tens of meters and the reservoir may be tens of kilometers. Furthermore, accurate representation of the path of a deviated well can be difficult. Incorporating the physics of injection and extraction can be made easier and more accurate with automated grid generation tools that incorporate wells as part of a background mesh that represents the reservoir. GEOMESH is a modeling tool developed for automating finite element grid generation. This tool maintains the geometric integrity of the geologic framework and produces optimal (Delaunay) tetrahedral grids. GEOMESH creates a 3D well as hexagonal segments formed along the path of the well. This well structure is tetrahedralized into a Delaunay mesh and then embedded into a background mesh. The well structure can be radially or vertically refined and each well layer is assigned a material property or can take on the material properties of the surrounding stratigraphy. The resulting embedded well can then be used by unstructured finite element models for gas and fluid flow in the vicinity of wells or tunnels. This 3D well representation allows the study of the free-surface of the well and surrounding stratigraphy. It reduces possible grid orientation effects, and allows better correlation between well sample data and the geologic model. The well grids also allow improved visualization for well and tunnel model analysis. 3D observation of the grids helps qualitative interpretation and can reveal features not apparent in fewer dimensions.

  15. 3-dimensional wells and tunnels for finite element grids

    SciTech Connect

    Cherry, T.A.; Gable, C.W.; Trease, H.

    1996-04-01

    Modeling fluid, vapor, and air injection and extraction from wells poses a number of problems. The length scale of well bores is centimeters, the region of high pressure gradient may be tens of meters and the reservoir may be tens of kilometers. Furthermore, accurate representation of the path of a deviated well can be difficult. Incorporating the physics of injection and extraction can be made easier and more accurate with automated grid generation tools that incorporate wells as part of a background mesh that represents the reservoir. GEOMESH is a modeling tool developed for automating finite element grid generation. This tool maintains the geometric integrity of the geologic framework and produces optimal (Delaunay) tetrahedral grids. GEOMESH creates a 3D well as hexagonal segments formed along the path of the well. This well structure is tetrahedralized into a Delaunay mesh and then embedded into a background mesh. The well structure can be radially or vertically refined and each well layer is assigned a material property or can take on the material properties of the surrounding stratigraphy. The resulting embedded well can then be used by unstructured finite element models for gas and fluid flow in the vicinity of wells or tunnels. This 3D well representation allows the study of the free- surface of the well and surrounding stratigraphy. It reduces possible grid orientation effects, and allows better correlation between well sample data and the geologic model. The well grids also allow improved visualization for well and tunnel model analysis. 3D observation of the grids helps qualitative interpretation and can reveal features not apparent in fewer dimensions.

  16. Computer-based learning materials for medical education: a model production.

    PubMed

    Mooney, G A; Bligh, J G

    1997-05-01

    Computer-based learning materials (CBL or courseware) have the potential to be valuable learning resources for medical education. However, CBL has failed to realize its potential primarily because of unstructured approaches towards design and development. This paper describes the courseware development model (CDM), a conceptual model produced and used by the Medical Education Unit at The University of Liverpool. The model describes a structured multi-disciplinary approach to the design and production of CBL materials. It promotes meticulous planning, communication and organization. The CDM draws on three areas of expertise: (1) education; (2) computer science; and (3) medical content. PMID:9231139

  17. Expectancies Underlying the Acceptability of Handicaps: The Pervasiveness of the Medical Model

    ERIC Educational Resources Information Center

    Abroms, Kippy; Kodera, Thomas L.

    1978-01-01

    Two groups of undergraduate students with diverse backgrounds ranked the acceptability of 15 handicapping conditions of which some were medical disorders and others were sociopsychological or functional impairments. Students adhered to the medical model, basing their judgments of acceptability on the amenability of a given handicap to medical…

  18. How Students Experience and Navigate Transitions in Undergraduate Medical Education: An Application of Bourdieu's Theoretical Model

    ERIC Educational Resources Information Center

    Balmer, Dorene F.; Richards, Boyd F.; Varpio, Lara

    2015-01-01

    Using Bourdieu's theoretical model as a lens for analysis, we sought to understand how students experience the undergraduate medical education (UME) milieu, focusing on how they navigate transitions from the preclinical phase, to the major clinical year (MCY), and to the preparation for residency phase. Twenty-two medical students participated in…

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

    ERIC Educational Resources Information Center

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

    2009-01-01

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

  20. Analyzing Traditional Medical Practitioners' Information-Seeking Behaviour Using Taylor's Information-Use Environment Model

    ERIC Educational Resources Information Center

    Olatokun, Wole Michael; Ajagbe, Enitan

    2010-01-01

    This survey-based study examined the information-seeking behaviour of traditional medical practitioners using Taylor's information use model. Respondents comprised all 160 traditional medical practitioners that treat sickle cell anaemia. Data were collected using an interviewer-administered, structured questionnaire. Frequency and percentage…

  1. Modeling and modification of medical 3D objects. The benefit of using a haptic modeling tool.

    PubMed

    Kling-Petersen, T; Rydmark, M

    2000-01-01

    The Computer Laboratory of the medical faculty in Goteborg (Mednet) has since the end of 1998 been one of a limited numbers of participants in the development of a new modeling tool together with SensAble Technologies Inc [http:¿www.sensable.com/]. The software called SensAble FreeForm was officially released at Siggraph September 1999. Briefly, the software mimics the modeling techniques traditionally used by clay artists. An imported model or a user defined block of "clay" can be modified using different tools such as a ball, square block, scrape etc via the use of a SensAble Technologies PHANToM haptic arm. The model will deform in 3D as a result of touching the "clay" with any selected tool and the amount of deformation is linear to the force applied. By getting instantaneous haptic as well as visual feedback, precise and intuitive changes are easily made. While SensAble FreeForm lacks several of the features normally associated with a 3D modeling program (such as text handling, application of surface and bumpmaps, high-end rendering engines, etc) it's strength lies in the ability to rapidly create non-geometric 3D models. For medical use, very few anatomically correct models are created from scratch. However, FreeForm features tools enable advanced modification of reconstructed or 3D scanned models. One of the main problems with 3D laserscanning of medical specimens is that the technique usually leaves holes or gaps in the dataset corresponding to areas in shadows such as orifices, deep grooves etc. By using FreeForms different tools, these defects are easily corrected and gaps are filled out. Similarly, traditional 3D reconstruction (based on serial sections etc) often shows artifacts as a result of the triangulation and/or tessellation processes. These artifacts usually manifest as unnatural ridges or uneven areas ("the accordion effect"). FreeForm contains a smoothing algorithm that enables the user to select an area to be modified and subsequently apply

  2. Medical mitigation model: quantifying the benefits of the public health response to a chemical terrorism attack.

    PubMed

    Good, Kevin; Winkel, David; VonNiederhausern, Michael; Hawkins, Brian; Cox, Jessica; Gooding, Rachel; Whitmire, Mark

    2013-06-01

    The Chemical Terrorism Risk Assessment (CTRA) and Chemical Infrastructure Risk Assessment (CIRA) are programs that estimate the risk of chemical terrorism attacks to help inform and improve the US defense posture against such events. One aspect of these programs is the development and advancement of a Medical Mitigation Model-a mathematical model that simulates the medical response to a chemical terrorism attack and estimates the resulting number of saved or benefited victims. At the foundation of the CTRA/CIRA Medical Mitigation Model is the concept of stock-and-flow modeling; "stocks" are states that individuals progress through during the event, while "flows" permit and govern movement from one stock to another. Using this approach, the model is able to simulate and track individual victims as they progress from exposure to an end state. Some of the considerations in the model include chemical used, type of attack, route and severity of exposure, response-related delays, detailed treatment regimens with efficacy defined as a function of time, medical system capacity, the influx of worried well individuals, and medical countermeasure availability. As will be demonstrated, the output of the CTRA/CIRA Medical Mitigation Model makes it possible to assess the effectiveness of the existing public health response system and develop and examine potential improvement strategies. Such a modeling and analysis capability can be used to inform first-responder actions/training, guide policy decisions, justify resource allocation, and direct knowledge-gap studies. PMID:22744439

  3. Autonomous, In-Flight Crew Health Risk Management for Exploration-Class Missions: Leveraging the Integrated Medical Model for the Exploration Medical System Demonstration Project

    NASA Technical Reports Server (NTRS)

    Butler, D. J.; Kerstman, E.; Saile, L.; Myers, J.; Walton, M.; Lopez, V.; McGrath, T.

    2011-01-01

    The Integrated Medical Model (IMM) captures organizational knowledge across the space medicine, training, operations, engineering, and research domains. IMM uses this knowledge in the context of a mission and crew profile to forecast risks to crew health and mission success. The IMM establishes a quantified, statistical relationship among medical conditions, risk factors, available medical resources, and crew health and mission outcomes. These relationships may provide an appropriate foundation for developing an in-flight medical decision support tool that helps optimize the use of medical resources and assists in overall crew health management by an autonomous crew with extremely limited interactions with ground support personnel and no chance of resupply.

  4. The choice of role models by students at a culturally diverse South African medical school.

    PubMed

    McLean, Michelle

    2004-03-01

    Role models have long been considered important in training medical students in the professional and ethical values of medicine. This report discusses role models identified by South African medical students in Years 1-5 of their study in a traditional programme. Most students considering having a role model important. As students progressed, faculty role models were more likely to be selected. A parent (the mother, in particular) or parents were, however, most frequently identified as role models by all students. Attributes ascribed to parents as role models (caring, sympathetic, self-sacrificing) are similar to those considered desirable for professional role models in medicine. These findings are considered in the light of global medical training and the need for faculties to provide appropriate role models for students. PMID:15203522

  5. Interfacial magnetic anisotropy from a 3-dimensional Rashba substrate

    NASA Astrophysics Data System (ADS)

    Li, Junwen; Haney, Paul M.

    2016-07-01

    We study the magnetic anisotropy which arises at the interface between a thin film ferromagnet and a 3-d Rashba material. We use a tight-binding model to describe the bilayer, and the 3-d Rashba material characterized by the spin-orbit strength α and the direction of broken bulk inversion symmetry n ̂ . We find an in-plane uniaxial anisotropy in the z ̂ × n ̂ direction, where z ̂ is the interface normal. For realistic values of α, the uniaxial anisotropy is of a similar order of magnitude as the bulk magnetocrystalline anisotropy. Evaluating the uniaxial anisotropy for a simplified model in 1-d shows that for small band filling, the in-plane easy axis anisotropy scales as α4 and results from a twisted exchange interaction between the spins in the 3-d Rashba material and the ferromagnet. For a ferroelectric 3-d Rashba material, n ̂ can be controlled with an electric field, and we propose that the interfacial magnetic anisotropy could provide a mechanism for electrical control of the magnetic orientation.

  6. 3-Dimensional simulations of storm dynamics on Saturn

    NASA Astrophysics Data System (ADS)

    Hueso, R.; Sanchez-Lavega, A.

    2000-10-01

    The formation and evolution of convective clouds in the atmosphere of Saturn is investigated using an anelastic three-dimensional time-dependent model with parameterized microphysics. The model is designed to study the development of moist convection on any of the four giant planets and has been previously used to investigate the formation of water convective storms in the jovian atmosphere. The role of water and ammonia in moist convection is investigated with varying deep concentrations. Results imply that most of the convective activity observed at Saturn may occur at the ammonia cloud deck while the formation of water moist convection may happen only when very strong constraints on the lower troposphere are met. Ammonia storms can ascend to the 300 mb level with vertical velocities around 30 ms-1. The seasonal effect on the thermal profile at the upper troposphere may have important effects on the development of ammonia storms. In the cases where water storms can develop they span many scale heights with peak vertical velocities around 160 ms-1 and cloud particles can be transported up to the 150 mb level. These predicted characteristics are similar to the Great White Spots observed in Saturn which, therefore, could be originated at the water cloud base level. This work has been supported by Gobierno Vasco PI 1997-34. R. Hueso acknowledges a PhD fellowship from Gobierno Vasco.

  7. Novel Radiobiological Gamma Index for Evaluation of 3-Dimensional Predicted Dose Distribution

    SciTech Connect

    Sumida, Iori; Yamaguchi, Hajime; Kizaki, Hisao; Aboshi, Keiko; Tsujii, Mari; Yoshikawa, Nobuhiko; Yamada, Yuji; Suzuki, Osamu; Seo, Yuji; Isohashi, Fumiaki; Yoshioka, Yasuo; Ogawa, Kazuhiko

    2015-07-15

    Purpose: To propose a gamma index-based dose evaluation index that integrates the radiobiological parameters of tumor control (TCP) and normal tissue complication probabilities (NTCP). Methods and Materials: Fifteen prostate and head and neck (H&N) cancer patients received intensity modulated radiation therapy. Before treatment, patient-specific quality assurance was conducted via beam-by-beam analysis, and beam-specific dose error distributions were generated. The predicted 3-dimensional (3D) dose distribution was calculated by back-projection of relative dose error distribution per beam. A 3D gamma analysis of different organs (prostate: clinical [CTV] and planned target volumes [PTV], rectum, bladder, femoral heads; H&N: gross tumor volume [GTV], CTV, spinal cord, brain stem, both parotids) was performed using predicted and planned dose distributions under 2%/2 mm tolerance and physical gamma passing rate was calculated. TCP and NTCP values were calculated for voxels with physical gamma indices (PGI) >1. We propose a new radiobiological gamma index (RGI) to quantify the radiobiological effects of TCP and NTCP and calculate radiobiological gamma passing rates. Results: The mean RGI gamma passing rates for prostate cases were significantly different compared with those of PGI (P<.03–.001). The mean RGI gamma passing rates for H&N cases (except for GTV) were significantly different compared with those of PGI (P<.001). Differences in gamma passing rates between PGI and RGI were due to dose differences between the planned and predicted dose distributions. Radiobiological gamma distribution was visualized to identify areas where the dose was radiobiologically important. Conclusions: RGI was proposed to integrate radiobiological effects into PGI. This index would assist physicians and medical physicists not only in physical evaluations of treatment delivery accuracy, but also in clinical evaluations of predicted dose distribution.

  8. Input shaped control of 3-dimensional maneuvers of flexible spacecraft

    NASA Technical Reports Server (NTRS)

    Singh, T.; Vadali, S. R.

    1992-01-01

    This paper deals with the control of three dimensional rotational maneuvers of flexible spacecraft. A spacecraft with a spherical hub and six symmetric appendages is considered here as a model. The appendages are long and flexible leading to low frequency vibration under any control action. To provide a comprehensive treatment of input shaped controllers, both open loop and closed loop controllers are considered. The minimum-time bang-bang and the near-minimum-time controller, used in conjunction with the shaped input technique are studied. In addition, a combination of a Liapunov controller with the shaped input control technique is proposed to take advantage of the simple feedback control strategy and augment it with a technique that can eliminate the vibratory motion of the flexible appendages more efficiently.

  9. An Empirical Assessment of a Technology Acceptance Model for Apps in Medical Education.

    PubMed

    Briz-Ponce, Laura; García-Peñalvo, Francisco José

    2015-11-01

    The evolution and the growth of mobile applications ("apps") in our society is a reality. This general trend is still upward and the app use has also penetrated the medical education community. However, there is a lot of unawareness of the students' and professionals' point of view about introducing "apps" within Medical School curriculum. The aim of this research is to design, implement and verify that the Technology Acceptance Model (TAM) can be employed to measure and explain the acceptance of mobile technology and "apps" within Medical Education. The methodology was based on a survey distributed to students and medical professionals from University of Salamanca. This model explains 46.7% of behavioral intention to use mobile devise or "apps" for learning and will help us to justify and understand the current situation of introducing "apps" into the Medical School curriculum. PMID:26411928

  10. A 3-Dimensional discrete fracture network generator to examine fracture-matrix interaction using TOUGH2

    SciTech Connect

    Ito, Kazumasa; Yongkoo, Seol

    2003-04-09

    Water fluxes in unsaturated, fractured rock involve the physical processes occurring at fracture-matrix interfaces within fracture networks. Modeling these water fluxes using a discrete fracture network model is a complicated effort. Existing preprocessors for TOUGH2 are not suitable to generate grids for fracture networks with various orientations and inclinations. There are several 3-D discrete-fracture-network simulators for flow and transport, but most of them do not capture fracture-matrix interaction. We have developed a new 3-D discrete-fracture-network mesh generator, FRACMESH, to provide TOUGH2 with information about the fracture network configuration and fracture-matrix interactions. FRACMESH transforms a discrete fracture network into a 3 dimensional uniform mesh, in which fractures are considered as elements with unique rock material properties and connected to surrounding matrix elements. Using FRACMESH, individual fractures may have uniform or random aperture distributions to consider heterogeneity. Fracture element volumes and interfacial areas are calculated from fracture geometry within individual elements. By using FRACMESH and TOUGH2, fractures with various inclinations and orientations, and fracture-matrix interaction, can be incorporated. In this paper, results of flow and transport simulations in a fractured rock block utilizing FRACMESH are presented.

  11. Phase transitions in a 3 dimensional lattice loop gas

    NASA Astrophysics Data System (ADS)

    MacKenzie, Richard; Nebia-Rahal, F.; Paranjape, M. B.

    2010-06-01

    We investigate, via Monte Carlo simulations, the phase structure of a system of closed, nonintersecting but otherwise noninteracting, loops in 3 Euclidean dimensions. The loops correspond to closed trajectories of massive particles and we find a phase transition as a function of their mass. We identify the order parameter as the average length of the loops at equilibrium. This order parameter exhibits a sharp increase as the mass is decreased through a critical value, the behavior seems to be a crossover transition. We believe that the model represents an effective description of the broken-symmetry sector of the 2+1 dimensional Abelian Higgs model, in the extreme strong coupling limit. The massive gauge bosons and the neutral scalars are decoupled, and the relevant low-lying excitations correspond to vortices and antivortices. The functional integral can be approximated by a sum over simple, closed vortex loop configurations. We present a novel fashion to generate nonintersecting closed loops, starting from a tetrahedral tessellation of three space. The two phases that we find admit the following interpretation: the usual Higgs phase and a novel phase which is heralded by the appearance of effectively infinitely long loops. We compute the expectation value of the Wilson loop operator and that of the Polyakov loop operator. The Wilson loop exhibits perimeter law behavior in both phases implying that the transition corresponds neither to the restoration of symmetry nor to confinement. The effective interaction between external charges is screened in both phases, however there is a dramatic increase in the polarization cloud in the novel phase as shown by the energy shift introduced by the Wilson loop.

  12. Regulation and 3 dimensional culture of tertiary follicle growth

    PubMed Central

    2012-01-01

    It has been revealed that multiple cohorts of tertiary follicles develop during some animal estrous cycle and the human menstrual cycle. To reach developmental competence, oocytes need the support of somatic cells. During embryogenesis, the primordial germ cells appear, travel to the gonadal rudiments, and form follicles. The female germ cells develop within the somatic cells of the ovary, granulosa cells, and theca cells. How the oocyte and follicle cells support each other has been seriously studied. The latest technologies in genes and proteins and genetic engineering have allowed us to collect a great deal of information about folliculogenesis. For example, a few web pages (http://www.ncbi.nlm.nih.gov; http://mrg.genetics.washington.edu) provide access to databases of genomes, sequences of transcriptomes, and various tools for analyzing and discovering genes important in ovarian development. Formation of the antrum (tertiary follicle) is the final phase of folliculogenesis and the transition from intraovarian to extraovian regulation. This final step coordinates with the hypothalamic-pituitary-ovarian axis. On the other hand, currently, follicle physiology is under intense investigation, as little is known about how to overcome women's ovarian problems or how to develop competent oocytes from in vitro follicle culture or transplantation. In this review, some of the known roles of hormones and some of the genes involved in tertiary follicle growth and the general characteristics of tertiary follicles are summarized. In addition, in vitro culture of tertiary follicles is also discussed as a study model and an assisted reproductive technology model. PMID:23106040

  13. The Arabian Gulf University College of Medicine and Medical Sciences: a successful model of a multinational medical school.

    PubMed

    Hamdy, Hossam; Anderson, M Brownell

    2006-12-01

    In the late 1970s, leaders of the Arabian [corrected] Gulf countries proposed a novel idea of a joint educational and cultural venture: establishing a new regional university based in the Kingdom of Bahrain that would be managed as a multinational consortium of Gulf countries including Saudi Arabia, United Arab Emirates, Kuwait, Oman, Qatar, and Bahrain. It was intended to promote higher education and research in the Gulf region; to serve the development needs of the region; to reflect the unique economic, social, and cultural attributes of the Gulf communities and their environments; and to respond to the health care needs of the member countries. Since its inception in 1982, the College of Medicine and Medical Sciences (CMMS) at Arabian Gulf University (AGU) has adopted the educational philosophy of problem-based learning (PBL) and self-directed, student-centered education. The curriculum is integrated, with early introduction of education to foster clinical skills and professional competencies. The strategic alliance with the health care systems in Bahrain and other Gulf regions has created a successful model of efficient and effective initialization of health care resources in the community. The experience that has accumulated at the AGU-CMMS from introducing innovative medical education has allowed it to take a leadership position in medical education in the Gulf region. The original goals of this unique experiment have been realized along with unanticipated outcomes of spearheading changes in medical education in the Gulf region. Old and new medical schools have adopted several characteristics of the AGU educational program. Several elements contributed to its success: a clear vision of providing quality medical education and realizing and sustaining this vision by a supportive leadership at the university and college levels; an alliance with the regional health care systems; a dedicated faculty who have been able to work as a team while continually

  14. Validation of the Integrated Medical Model Using Historical Space Flight Data

    NASA Technical Reports Server (NTRS)

    Kerstman, Eric L.; Minard, Charles G.; FreiredeCarvalho, Mary H.; Walton, Marlei E.; Myers, Jerry G., Jr.; Saile, Lynn G.; Lopez, Vilma; Butler, Douglas J.; Johnson-Throop, Kathy A.

    2010-01-01

    The Integrated Medical Model (IMM) utilizes Monte Carlo methodologies to predict the occurrence of medical events, utilization of resources, and clinical outcomes during space flight. Real-world data may be used to demonstrate the accuracy of the model. For this analysis, IMM predictions were compared to data from historical shuttle missions, not yet included as model source input. Initial goodness of fit test-ing on International Space Station data suggests that the IMM may overestimate the number of occurrences for three of the 83 medical conditions in the model. The IMM did not underestimate the occurrence of any medical condition. Initial comparisons with shuttle data demonstrate the importance of understanding crew preference (i.e., preferred analgesic) for accurately predicting the utilization of re-sources. The initial analysis demonstrates the validity of the IMM for its intended use and highlights areas for improvement.

  15. The Integrated Medical Model: A Decision Support Tool for In-flight Crew Health Care

    NASA Technical Reports Server (NTRS)

    Butler, Doug

    2009-01-01

    This viewgraph presentation reviews the development of an Integrated Medical Model (IMM) decision support tool for in-flight crew health care safety. Clinical methods, resources, and case scenarios are also addressed.

  16. Fast Model Adaptation for Automated Section Classification in Electronic Medical Records.

    PubMed

    Ni, Jian; Delaney, Brian; Florian, Radu

    2015-01-01

    Medical information extraction is the automatic extraction of structured information from electronic medical records, where such information can be used for improving healthcare processes and medical decision making. In this paper, we study one important medical information extraction task called section classification. The objective of section classification is to automatically identify sections in a medical document and classify them into one of the pre-defined section types. Training section classification models typically requires large amounts of human labeled training data to achieve high accuracy. Annotating institution-specific data, however, can be both expensive and time-consuming; which poses a big hurdle for adapting a section classification model to new medical institutions. In this paper, we apply two advanced machine learning techniques, active learning and distant supervision, to reduce annotation cost and achieve fast model adaptation for automated section classification in electronic medical records. Our experiment results show that active learning reduces the annotation cost and time by more than 50%, and distant supervision can achieve good model accuracy using weakly labeled training data only. PMID:26262005

  17. Anatomically Based Geometric Modelling Using Medical Image Data: Methods and Programs

    PubMed Central

    Wang, Monan; Sun, Lei; Liu, Yuming

    2015-01-01

    The human organs geometric modeling software which can achieve two-dimensional medical image browsing, pretreatment and three dimensional (3D) reconstruction in this paper is designed. This software implements medical image segmentation using the method combining the region growing and the interactive segmentation. Also, the MC surface reconstruction algorithm is utilized to achieve the three-dimensional reconstruction. Furthermore, the software is projected by Visual C++. And then, to legitimately express the structural information of skeleton and muscle, the software is employed to obtain the geometric model using the segmentation and three-dimensional reconstruction for data of skeleton and muscle medical images of the object of study. PMID:26089991

  18. Research on Medical Image Enhancement Algorithm Based on GSM Model for Wavelet Coefficients

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Jiang, Nian-de; Ning, Xing

    For the complexity and application diversity of medical CT image, this article presents a medical CT Image enhancing algorithm based on Gaussian Scale Mixture Model for wavelet coefficient in the study of wavelet multi-scale analysis. The noisy image is firstly denoised in auto-adapted Wiener filter. Secondly, through the qualitative analysis and classification of wavelet coefficients for the signal and noise, the wavelet's approximate distribution and statistical characteristics are described, combining GSM(Gaussian scale mixture) model for wavelet coefficient in this paper. It is shown that this algorithm can improve the denoised result and enhanced the medical CT image obviously.

  19. A Diverging View of Role Modeling in Medical Education

    ERIC Educational Resources Information Center

    Sandhu, Gurjit; Rich, Jessica V.; Magas, Christopher; Walker, G. Ross

    2015-01-01

    Research in the area of role modeling has primarily focused on the qualities and attributes of exceptional role models, and less attention has been given to the act of role modeling itself (Elzubeir & Rizk, 2001; Jochemsen-van der Leeuw, van Dijk, van Etten-Jamaludin, & Wieringa-de Waard, 2013; Wright, 1996; Wright, Wong, & Newill,…

  20. Development of 3-dimensional time-dependent density functional theory and its application to gas diffusion in nanoporous materials.

    PubMed

    Liu, Yu

    2016-05-11

    I developed a novel time-dependent density functional theory (TDDFT) and applied it to complicated 3-dimensional systems for the first time. Superior to conventional TDDFT, the diffusion coefficient is modeled as a function of density profile, which is self-determined by the entropy scaling rule instead using an input parameter. The theory was employed to mimic gas diffusion in a nanoporous material. The TDDFT prediction on the transport diffusivity was reasonable compared to simulations. Moreover, the time-dependent density profiles gave an insight into the microscopic mechanism of the diffusion process. PMID:27121986

  1. Testing a Mediational Model of Communication Among Medical Staff and Families of Cancer Patients

    ERIC Educational Resources Information Center

    Gionta, Dana A.; Harlow, Lisa L.; Loitman, Jane E.; Leeman, Joanne M.

    2005-01-01

    Three structural equation models of communication between family members and medical staff were examined to understand relations among staff accessibility, inhibitory family attitudes, getting communication needs met, perceived stress, and satisfaction with communication. Compared to full and direct models, a mediational model fit best in which…

  2. Compression-based aggregation model for medical web services.

    PubMed

    Al-Shammary, Dhiah; Khalil, Ibrahim

    2010-01-01

    Many organizations such as hospitals have adopted Cloud Web services in applying their network services to avoid investing heavily computing infrastructure. SOAP (Simple Object Access Protocol) is the basic communication protocol of Cloud Web services that is XML based protocol. Generally,Web services often suffer congestions and bottlenecks as a result of the high network traffic that is caused by the large XML overhead size. At the same time, the massive load on Cloud Web services in terms of the large demand of client requests has resulted in the same problem. In this paper, two XML-aware aggregation techniques that are based on exploiting the compression concepts are proposed in order to aggregate the medical Web messages and achieve higher message size reduction. PMID:21097152

  3. Fusing Continuous-Valued Medical Labels Using a Bayesian Model.

    PubMed

    Zhu, Tingting; Dunkley, Nic; Behar, Joachim; Clifton, David A; Clifford, Gari D

    2015-12-01

    With the rapid increase in volume of time series medical data available through wearable devices, there is a need to employ automated algorithms to label data. Examples of labels include interventions, changes in activity (e.g. sleep) and changes in physiology (e.g. arrhythmias). However, automated algorithms tend to be unreliable resulting in lower quality care. Expert annotations are scarce, expensive, and prone to significant inter- and intra-observer variance. To address these problems, a Bayesian Continuous-valued Label Aggregator (BCLA) is proposed to provide a reliable estimation of label aggregation while accurately infer the precision and bias of each algorithm. The BCLA was applied to QT interval (pro-arrhythmic indicator) estimation from the electrocardiogram using labels from the 2006 PhysioNet/Computing in Cardiology Challenge database. It was compared to the mean, median, and a previously proposed Expectation Maximization (EM) label aggregation approaches. While accurately predicting each labelling algorithm's bias and precision, the root-mean-square error of the BCLA was 11.78 ± 0.63 ms, significantly outperforming the best Challenge entry (15.37 ± 2.13 ms) as well as the EM, mean, and median voting strategies (14.76 ± 0.52, 17.61 ± 0.55, and 14.43 ± 0.57 ms respectively with p < 0.0001). The BCLA could therefore provide accurate estimation for medical continuous-valued label tasks in an unsupervised manner even when the ground truth is not available. PMID:26036335

  4. A Novel Method of Orbital Floor Reconstruction Using Virtual Planning, 3-Dimensional Printing, and Autologous Bone.

    PubMed

    Vehmeijer, Maarten; van Eijnatten, Maureen; Liberton, Niels; Wolff, Jan

    2016-08-01

    Fractures of the orbital floor are often a result of traffic accidents or interpersonal violence. To date, numerous materials and methods have been used to reconstruct the orbital floor. However, simple and cost-effective 3-dimensional (3D) printing technologies for the treatment of orbital floor fractures are still sought. This study describes a simple, precise, cost-effective method of treating orbital fractures using 3D printing technologies in combination with autologous bone. Enophthalmos and diplopia developed in a 64-year-old female patient with an orbital floor fracture. A virtual 3D model of the fracture site was generated from computed tomography images of the patient. The fracture was virtually closed using spline interpolation. Furthermore, a virtual individualized mold of the defect site was created, which was manufactured using an inkjet printer. The tangible mold was subsequently used during surgery to sculpture an individualized autologous orbital floor implant. Virtual reconstruction of the orbital floor and the resulting mold enhanced the overall accuracy and efficiency of the surgical procedure. The sculptured autologous orbital floor implant showed an excellent fit in vivo. The combination of virtual planning and 3D printing offers an accurate and cost-effective treatment method for orbital floor fractures. PMID:27137437

  5. Biphasic response of cell invasion to matrix stiffness in 3-dimensional biopolymer networks

    PubMed Central

    Lang, Nadine R.; Skodzek, Kai; Hurst, Sebastian; Mainka, Astrid; Steinwachs, Julian; Schneider, Julia; Aifantis, Katerina E.; Fabry, Ben

    2015-01-01

    When cells come in contact with an adhesive matrix, they begin to spread and migrate with a speed that depends on the stiffness of the extracellular matrix. On a flat surface, migration speed decreases with matrix stiffness mainly due to an increased stability of focal adhesions. In a 3-dimensional (3D) environment, cell migration is thought to be additionally impaired by the steric hindrance imposed by the surrounding matrix. For porous 3D biopolymer networks such as collagen gels, however, the effect of matrix stiffness on cell migration is difficult to separate from effects of matrix pore size and adhesive ligand density, and is therefore unknown. Here we used glutaraldehyde as a crosslinker to increase the stiffness of self-assembled collagen biopolymer networks independently of collagen concentration or pore size. Breast carcinoma cells were seeded onto the surface of 3D collagen gels, and the invasion depth was measured after 3 days of culture. Cell invasion in gels with pore sizes larger than 5 μm increased with higher gel stiffness, whereas invasion in gels with smaller pores decreased with higher gel stiffness. These data show that 3D cell invasion is enhanced by higher matrix stiffness, opposite to cell behavior in 2D, as long as the pore size does not fall below a critical value where it causes excessive steric hindrance. These findings may be important for optimizing the recellularization of soft tissue implants or for the design of 3D invasion models in cancer research. PMID:25462839

  6. Fusion of radar data to extract 3-dimensional objects LDRD final report

    SciTech Connect

    Fellerhoff, R.; Hensley, B.; Carande, R.; Burkhart, G.; Ledner, R.

    1997-03-01

    Interferometric Synthetic Aperture Radar (IFSAR) is a very promising technology for remote mapping of 3-Dimensional objects. In particular, 3-D maps of urban areas are extremely important to a wide variety of users, both civilian and military. However, 3-D maps produced by traditional optical stereo (stereogrammetry) techniques can be quite expensive to obtain, and accurate urban maps can only be obtained with a large amount of human-intensive interpretation work. IFSAR has evolved over the last decade as a mapping technology that promises to eliminate much of the human-intensive work in producing elevation maps. However, IFSAR systems have only been robustly demonstrated in non-urban areas, and have not traditionally been able to produce data with enough detail to be of general use in urban areas. Sandia Laboratories Twin Otter IFSAR was the first mapping radar system with the proper parameter set to provide sufficiently detailed information in a large number of urban areas. The goal of this LDRD was to fuse previously unused information derived from IFSAR data in urban areas that can be used to extract accurate digital elevation models (DEMs) over wide areas without intensive human interaction.

  7. Simultaneous PET and Multispectral 3-Dimensional Fluorescence Optical Tomography Imaging System

    PubMed Central

    Li, Changqing; Yang, Yongfeng; Mitchell, Gregory S.; Cherry, Simon R.

    2015-01-01

    Integrated PET and 3-dimensional (3D) fluorescence optical tomography (FOT) imaging has unique and attractive features for in vivo molecular imaging applications. We have designed, built, and evaluated a simultaneous PET and 3D FOT system. The design of the FOT system is compatible with many existing small-animal PET scanners. Methods The 3D FOT system comprises a novel conical mirror that is used to view the whole-body surface of a mouse with an electron-multiplying charge-coupled device camera when a collimated laser beam is projected on the mouse to stimulate fluorescence. The diffusion equation was used to model the propagation of optical photons inside the mouse body, and 3D fluorescence images were reconstructed iteratively from the fluorescence intensity measurements measured from the surface of the mouse. Insertion of the conical mirror into the gantry of a small-animal PET scanner allowed simultaneous PET and 3D FOT imaging. Results The mutual interactions between PET and 3D FOT were evaluated experimentally. PET has negligible effects on 3D FOT performance. The inserted conical mirror introduces a reduction in the sensitivity and noise-equivalent count rate of the PET system and increases the scatter fraction. PET–FOT phantom experiments were performed. An in vivo experiment using both PET and FOT was also performed. Conclusion Phantom and in vivo experiments demonstrate the feasibility of simultaneous PET and 3D FOT imaging. The first in vivo simultaneous PET–FOT results are reported. PMID:21810591

  8. Copula bivariate probit models: with an application to medical expenditures.

    PubMed

    Winkelmann, Rainer

    2012-12-01

    The bivariate probit model is frequently used for estimating the effect of an endogenous binary regressor (the 'treatment') on a binary health outcome variable. This paper discusses simple modifications that maintain the probit assumption for the marginal distributions while introducing non-normal dependence using copulas. In an application of the copula bivariate probit model to the effect of insurance status on the absence of ambulatory health care expenditure, a model based on the Frank copula outperforms the standard bivariate probit model. PMID:22025413

  9. Medical Image Fusion Based on Rolling Guidance Filter and Spiking Cortical Model

    PubMed Central

    Shuaiqi, Liu; Jie, Zhao; Mingzhu, Shi

    2015-01-01

    Medical image fusion plays an important role in diagnosis and treatment of diseases such as image-guided radiotherapy and surgery. Although numerous medical image fusion methods have been proposed, most of these approaches are sensitive to the noise and usually lead to fusion image distortion, and image information loss. Furthermore, they lack universality when dealing with different kinds of medical images. In this paper, we propose a new medical image fusion to overcome the aforementioned issues of the existing methods. It is achieved by combining with rolling guidance filter (RGF) and spiking cortical model (SCM). Firstly, saliency of medical images can be captured by RGF. Secondly, a self-adaptive threshold of SCM is gained by utilizing the mean and variance of the source images. Finally, fused image can be gotten by SCM motivated by RGF coefficients. Experimental results show that the proposed method is superior to other current popular ones in both subjectively visual performance and objective criteria. PMID:26146512

  10. Medical imaging education in biomedical engineering curriculum: courseware development and application through a hybrid teaching model.

    PubMed

    Zhao, Weizhao; Li, Xiping; Chen, Hairong; Manns, Fabrice

    2012-01-01

    Medical Imaging is a key training component in Biomedical Engineering programs. Medical imaging education is interdisciplinary training, involving physics, mathematics, chemistry, electrical engineering, computer engineering, and applications in biology and medicine. Seeking an efficient teaching method for instructors and an effective learning environment for students has long been a goal for medical imaging education. By the support of NSF grants, we developed the medical imaging teaching software (MITS) and associated dynamic assessment tracking system (DATS). The MITS/DATS system has been applied to junior and senior medical imaging classes through a hybrid teaching model. The results show that student's learning gain improved, particularly in concept understanding and simulation project completion. The results also indicate disparities in subjective perception between junior and senior classes. Three institutions are collaborating to expand the courseware system and plan to apply it to different class settings. PMID:23367069

  11. A sequential decision-theoretic model for medical diagnostic system.

    PubMed

    Li, Aiping; Jin, Songchang; Zhang, Lumin; Jia, Yan

    2015-01-01

    Although diagnostic expert systems using a knowledge base which models decision-making of traditional experts can provide important information to non-experts, they tend to duplicate the errors made by experts. Decision-Theoretic Model (DTM) is therefore very useful in expert system since they prevent experts from incorrect reasoning under uncertainty. For the diagnostic expert system, corresponding DTM and arithmetic are studied and a sequential diagnostic decision-theoretic model based on Bayesian Network is given. In the model, the alternative features are categorized into two classes (including diseases features and test features), then an arithmetic for prior of test is provided. The different features affect other features weights are also discussed. Bayesian Network is adopted to solve uncertainty presentation and propagation. The model can help knowledge engineers model the knowledge involved in sequential diagnosis and decide evidence alternative priority. A practical example of the models is also presented: at any time of the diagnostic process the expert is provided with a dynamically updated list of suggested tests in order to support him in the decision-making problem about which test to execute next. The results show it is better than the traditional diagnostic model which is based on experience. PMID:26410326

  12. Forecasting the adoption of new medical technology using the Bass model.

    PubMed

    Sillup, G P

    1992-12-01

    A mathematical model, the Bass model, was used to forecast the adoption of new medical technology based on durable equipment. When the model was applied to five successful medical technologies, actual unit sales were predicted for three. The technologies investigated are computed tomography (CT scan), magnetic resonance imaging (MRI), ultrasound, hemodialysis, and lithotripsy. Because unit sales data for dialysis and ultrasound could not be obtained or estimated from secondary sources for the years immediately after market entry, application of the Bass model produced questionable results for those technologies. However, results for CT scan, MRI, and lithotripsy suggest that this model can be used to predict the adoption of new medical technology based on durable equipment when annual unit sales data can be estimated for the period immediately after market entry. PMID:10123584

  13. Model-based segmentation of medical x-ray images

    NASA Astrophysics Data System (ADS)

    Hoare, Frederick; de Jager, Gerhard

    1994-03-01

    This paper discusses the methods used to model the structure of x-ray images of the human body and the individual organs within the body. A generic model of a region is built up from x-ray images to aid in automatic segmentation. By using the ribs from a chest x-ray image as an example, it is shown how models of the different organs can be generated. The generic model of the chest region is built up by using a priori knowledge of the physical structure of the human body. The models of the individual organs are built up by using knowledge of the structure of the organs as well as other information contained within each image. Each image is unique and therefore information from the region surrounding the organs in the image has to be taken into account when adapting the generic model to individual images. Results showing the application of these techniques to x-ray images of the chest region, the labelling of individual organs, and the generation of models of the ribs are presented.

  14. Specialty choice preference of medical students according to personality traits by Five-Factor Model

    PubMed Central

    Kwon, Oh Young; Park, So Youn

    2016-01-01

    Purpose: The purpose of this study was to determine the relationship between personality traits, using the Five-Factor Model, and characteristics and motivational factors affecting specialty choice in Korean medical students. Methods: A questionnaire survey of Year 4 medical students (n=110) in July 2015 was administered. We evaluated the personality traits of Extraversion, Agreeableness, Conscientiousness, Neuroticism, and Openness by using the Korean version of Big Five Inventory. Questions about general characteristics, medical specialties most preferred as a career, motivational factors in determining specialty choice were included. Data between five personality traits and general characteristics and motivational factors affecting specialty choice were analyzed using Student t-test, Mann-Whitney test and analysis of variance. Results: Of the 110 eligible medical students, 105 (95.4% response rate) completed the questionnaire. More Agreeableness students preferred clinical medicine to basic medicine (p=0.010) and more Openness students preferred medical departments to others (p=0.031). Personal interest was the significant motivational factors in more Openness students (p=0.003) and Conscientiousness students (p=0.003). Conclusion: Medical students with more Agreeableness were more likely to prefer clinical medicine and those with more Openness preferred medical departments. Personal interest was a significant influential factor determining specialty choice in more Openness and Conscientiousness students. These findings may be helpful to medical educators or career counselors in the specialty choice process. PMID:26838573

  15. Estimating the costs of intensity-modulated and 3-dimensional conformal radiotherapy in Ontario

    PubMed Central

    Yong, J.H.E.; McGowan, T.; Redmond-Misner, R.; Beca, J.; Warde, P.; Gutierrez, E.; Hoch, J.S.

    2016-01-01

    Background Radiotherapy is a common treatment for many cancers, but up-to-date estimates of the costs of radiotherapy are lacking. In the present study, we estimated the unit costs of intensity-modulated radiotherapy (imrt) and 3-dimensional conformal radiotherapy (3D-crt) in Ontario. Methods An activity-based costing model was developed to estimate the costs of imrt and 3D-crt in prostate cancer. It included the costs of equipment, staff, and supporting infrastructure. The framework was subsequently adapted to estimate the costs of radiotherapy in breast cancer and head-and-neck cancer. We also tested various scenarios by varying the program maturity and the use of volumetric modulated arc therapy (vmat) alongside imrt. Results From the perspective of the health care system, treating prostate cancer with imrt and 3D-crt respectively cost $12,834 and $12,453 per patient. The cost of radiotherapy ranged from $5,270 to $14,155 and was sensitive to analytic perspective, radiation technique, and disease site. Cases of head-and-neck cancer were the most costly, being driven by treatment complexity and fractions per treatment. Although imrt was more costly than 3D-crt, its cost will likely decline over time as programs mature and vmat is incorporated. Conclusions Our costing model can be modified to estimate the costs of 3D-crt and imrt for various disease sites and settings. The results demonstrate the important role of capital costs in studies of radiotherapy cost from a health system perspective, which our model can accommodate. In addition, our study established the need for future analyses of imrt cost to consider how vmat affects time consumption. PMID:27330359

  16. Predicting diffusive transport of cationic liposomes in 3-dimensional tumor spheroids

    PubMed Central

    Wientjes, Michael G.; Yeung, Bertrand Z.; Lu, Ze; Wientjes, M. Guillaume; Au, Jessie L.S.

    2014-01-01

    Nanotechnology is widely used in cancer research. Models that predict nanoparticle transport and delivery in tumors (including subcellular compartments) would be useful tools. This study tested the hypothesis that diffusive transport of cationic liposomes in 3-dimensional (3D) systems can be predicted based on liposome-cell biointerface parameters (binding, uptake, retention) and liposome diffusivity.Liposomes comprising different amounts of cationic and fusogenic lipids (10-30 mol% DOTAP or 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine,1-20 mol% DOPE or 1,2-dioleoyl-3-trimethylammonium-propane, +25 to +44 mV zeta potential) were studied. We (a) measured liposome-cell biointerface parameters in monolayer cultures, and (b) calculated effective diffusivity based on liposome size and spheroid composition. The resulting parameters were used to simulate the liposome concentration-depth profiles in 3D spheroids. The simulated results agreed with the experimental results for liposomes comprising 10-30 mol% DOTAP and ≤10 mol% DOPE, but not for liposomes with higher DOPE content. For the latter, model modifications to account for time-dependent extracellular concentration decrease and liposomesize increase did not improve the predictions. The difference among low- and high-DOPE liposomessuggestsconcentration-dependent DOPE properties in 3D systems that were not captured in monolayers. Taken together, our earlier and present studies indicate the diffusive transport of neutral, anionic and cationic nanoparticles (polystyrene beads and liposomes, 20-135 nm diameter, -49 to +44 mV) in 3D spheroids, with the exception of liposomes comprising >10 mol% DOPE, can be predicted based on the nanoparticle-cell biointerface and nanoparticle diffusivity. Applying the model to low-DOPE liposomes showed that changes in surface charge affected the liposome localization in intratumoralsubcompartments within spheroids. PMID:24995948

  17. Multilevel Modeling and Policy Development: Guidelines and Applications to Medical Travel

    PubMed Central

    Garcia-Garzon, Eduardo; Zhukovsky, Peter; Haller, Elisa; Plakolm, Sara; Fink, David; Petrova, Dafina; Mahalingam, Vaishali; Menezes, Igor G.; Ruggeri, Kai

    2016-01-01

    Medical travel has expanded rapidly in recent years, resulting in new markets and increased access to medical care. Whereas several studies investigated the motives of individuals seeking healthcare abroad, the conventional analytical approach is limited by substantial caveats. Classical techniques as found in the literature cannot provide sufficient insight due to the nested nature of data generated. The application of adequate analytical techniques, specifically multilevel modeling, is scarce to non-existent in the context of medical travel. This study introduces the guidelines for application of multilevel techniques in public health research by presenting an application of multilevel modeling in analyzing the decision-making patterns of potential medical travelers. Benefits and potential limitations are discussed. PMID:27252672

  18. Multilevel Modeling and Policy Development: Guidelines and Applications to Medical Travel.

    PubMed

    Garcia-Garzon, Eduardo; Zhukovsky, Peter; Haller, Elisa; Plakolm, Sara; Fink, David; Petrova, Dafina; Mahalingam, Vaishali; Menezes, Igor G; Ruggeri, Kai

    2016-01-01

    Medical travel has expanded rapidly in recent years, resulting in new markets and increased access to medical care. Whereas several studies investigated the motives of individuals seeking healthcare abroad, the conventional analytical approach is limited by substantial caveats. Classical techniques as found in the literature cannot provide sufficient insight due to the nested nature of data generated. The application of adequate analytical techniques, specifically multilevel modeling, is scarce to non-existent in the context of medical travel. This study introduces the guidelines for application of multilevel techniques in public health research by presenting an application of multilevel modeling in analyzing the decision-making patterns of potential medical travelers. Benefits and potential limitations are discussed. PMID:27252672

  19. How to Teach Psychiatry to Medical Undergraduates in India?: A Model

    PubMed Central

    Manohari, S. M.; Johnson, Pradeep R.; Galgali, Ravindra Baburao

    2013-01-01

    Psychiatry is not considered important by most medical students. But knowledge of psychiatry is essential for all doctors as psychiatric problems are prevalent in the population either as part of other physical illnesses or independently. All medical practitioners need skills in communication and forming empathy and the ability to counsel that are learnt in psychiatry. Nearly all medical students feel psychiatry is not scientific enough and psychiatrists are peculiar. We need to make psychiatry interesting, and impart skills and techniques to practice psychiatry at the primary care level and in the process change the misconceptions students have of psychiatry. We present a model to accomplish this. PMID:23833338

  20. [A novel model of the medical instrumentation--an overview of wearable sensors and systems].

    PubMed

    Deng, Qin-kai

    2006-09-01

    The traditional medical instrumentation is now not suited for the transformation of the present healthcare model. It's an attempt to make a breakthrough on traditions to develop wearable sensors/systems. Five articles about wearable technology are selected by this special topic. And our aim is to inspire the designers of medical devices to grasp the chance and to take a vigorous action on innovatory developments, so as to satisfy the huge requirements of the healthcare market, and to open a new era of the medical device industry. PMID:17165560

  1. Active shape models incorporating isolated landmarks for medical image annotation

    NASA Astrophysics Data System (ADS)

    Norajitra, Tobias; Meinzer, Hans-Peter; Stieltjes, Bram; Maier-Hein, Klaus H.

    2014-03-01

    Apart from their robustness in anatomic surface segmentation, purely surface based 3D Active Shape Models lack the ability to automatically detect and annotate non-surface key points of interest. However, annotation of anatomic landmarks is desirable, as it yields additional anatomic and functional information. Moreover, landmark detection might help to further improve accuracy during ASM segmentation. We present an extension of surface-based 3D Active Shape Models incorporating isolated non-surface landmarks. Positions of isolated and surface landmarks are modeled conjoint within a point distribution model (PDM). Isolated landmark appearance is described by a set of haar-like features, supporting local landmark detection on the PDM estimates using a kNN-Classi er. Landmark detection was evaluated in a leave-one-out cross validation on a reference dataset comprising 45 CT volumes of the human liver after shape space projection. Depending on the anatomical landmark to be detected, our experiments have shown in about 1/4 up to more than 1/2 of all test cases a signi cant improvement in detection accuracy compared to the position estimates delivered by the PDM. Our results encourage further research with regard to the combination of shape priors and machine learning for landmark detection within the Active Shape Model Framework.

  2. A model for training medical student innovators: the Harvard Medical School Center for Primary Care Abundance Agents of Change program

    PubMed Central

    Duong, David B.; Sullivan, Erin E.; Minter-Jordan, Myechia; Giesen, Lindsay; Ellner, Andrew L.

    2016-01-01

    Background In 2013, the Harvard Medical School Center for Primary Care established the Abundance Agents of Change (AoC) program to promote interprofessional learning and innovation, increase partnership between 15 academic and community health centers (CHCs) in Boston's most under-served communities, and increase medical student interest in primary care careers. Methods The AoC is modeled in the form of a ‘grants challenge’, offering $20,000 to interprofessional student teams to develop an innovative solution that addresses a healthcare delivery need identified by CHCs. The program's initial two years were characterized by a four-stage process which included working with CHCs and crafting a request for proposals, forming interprofessional 20 student teams comprising students from across and outside of Harvard University, training students using a systems-based innovation curriculum, and performing program evaluation. Results Our evaluation data from cohorts 1 and 2 of the AoC program demonstrate that we succeeded in training students as innovators and members of interprofessional teams. We also learned valuable lessons regarding creating better alignment with CHC priorities, extending the program cycle from 12 to 18 months, and changing the way funding is disbursed to 25 students, which will be incorporated in later versions of the program. Conclusions Based on our experience and evaluation data, we believe that this program is a replicable way to train students as innovators and members of interprofessional teams to address the current complex healthcare environment. PMID:27306994

  3. Model-Driven Safety Analysis of Closed-Loop Medical Systems

    PubMed Central

    Pajic, Miroslav; Mangharam, Rahul; Sokolsky, Oleg; Arney, David; Goldman, Julian; Lee, Insup

    2013-01-01

    In modern hospitals, patients are treated using a wide array of medical devices that are increasingly interacting with each other over the network, thus offering a perfect example of a cyber-physical system. We study the safety of a medical device system for the physiologic closed-loop control of drug infusion. The main contribution of the paper is the verification approach for the safety properties of closed-loop medical device systems. We demonstrate, using a case study, that the approach can be applied to a system of clinical importance. Our method combines simulation-based analysis of a detailed model of the system that contains continuous patient dynamics with model checking of a more abstract timed automata model. We show that the relationship between the two models preserves the crucial aspect of the timing behavior that ensures the conservativeness of the safety analysis. We also describe system design that can provide open-loop safety under network failure. PMID:24177176

  4. A Comparison of different learning models used in Data Mining for Medical Data

    NASA Astrophysics Data System (ADS)

    Srimani, P. K.; Koti, Manjula Sanjay

    2011-12-01

    The present study aims at investigating the different Data mining learning models for different medical data sets and to give practical guidelines to select the most appropriate algorithm for a specific medical data set. In practical situations, it is absolutely necessary to take decisions with regard to the appropriate models and parameters for diagnosis and prediction problems. Learning models and algorithms are widely implemented for rule extraction and the prediction of system behavior. In this paper, some of the well-known Machine Learning(ML) systems are investigated for different methods and are tested on five medical data sets. The practical criteria for evaluating different learning models are presented and the potential benefits of the proposed methodology for diagnosis and learning are suggested.

  5. Two Models of Integrating Buprenorphine Treatment and Medical Staff within Formerly "Drug-Free" Outpatient Programs.

    PubMed

    Monico, Laura; Schwartz, Robert P; Gryczynski, Jan; O'Grady, Kevin E; Mitchell, Shannon Gwin

    2016-01-01

    "Drug-free" outpatient programs deliver treatment to the largest number of patients of all treatment modalities in the U.S., providing a significant opportunity to expand access to medication treatments for substance use disorders. This analysis examined staff perceptions of organizational dynamics associated with the delivery of buprenorphine maintenance within three formerly "drug-free" outpatient treatment programs. Semi-structured interviews (N = 15) were conducted with counseling and medical staff, and respondents were predominantly African American (n = 11) and female (n = 12). Themes and concepts related to medical staff integration emerged through an inductive and iterative coding process using Atlas.ti qualitative analysis software. Two treatment clinics incorporated buprenorphine maintenance into their programs using a co-located model of care. Their staff generally reported greater intra-organizational discord regarding the best ways to combine medication and counseling compared to the clinic using an integrated model of care. Co-located program staff reported less communication between medical and clinical staff, which contributed to some uncertainty about proper dosing and concerns about the potential for medication diversion. Clinics that shift from "drug-free" to incorporating buprenorphine maintenance should consider which model of care they wish to adapt and how to train staff and structure staff communication. PMID:26940870

  6. Studies of Cosmic Ray Modulation and Energetic Particle Propagation in Time-Dependent 3-Dimensional Heliospheric Magnetic Fields

    NASA Technical Reports Server (NTRS)

    Zhang, Ming

    2005-01-01

    The primary goal of this project was to perform theoretical calculations of propagation of cosmic rays and energetic particles in 3-dimensional heliospheric magnetic fields. We used Markov stochastic process simulation to achieve to this goal. We developed computation software that can be used to study particle propagation in, as two examples of heliospheric magnetic fields that have to be treated in 3 dimensions, a heliospheric magnetic field suggested by Fisk (1996) and a global heliosphere including the region beyond the termination shock. The results from our model calculations were compared with particle measurements from Ulysses, Earth-based spacecraft such as IMP-8, WIND and ACE, Voyagers and Pioneers in outer heliosphere for tests of the magnetic field models. We particularly looked for features of particle variations that can allow us to significantly distinguish the Fisk magnetic field from the conventional Parker spiral field. The computer code will eventually lead to a new generation of integrated software for solving complicated problems of particle acceleration, propagation and modulation in realistic 3-dimensional heliosphere of realistic magnetic fields and the solar wind with a single computation approach.

  7. Standardization in the field of medical image management: the contribution of the MIMOSA model.

    PubMed

    Gibaud, B; Garfagni, H; Aubry, F; Pokropek, A T; Chameroy, V; Bizais, Y; Di Paola, R

    1998-02-01

    This paper deals with the development of standards in the field of medical imaging and picture archiving and communication systems (PACS's), and notably concerning the interworking between PACS's and hospital information systems (HIS). It explains, in detail, how a conceptual model of the management of medical images, such as the medical image management in an open system architecture (MIMOSA) model, can contribute to the development of standards for medical image management and PACS's. This contribution is twofold: 1) Since the model lists and structures the concepts and resources involved to make the images available to the users when and where they are required, and describes the interactions between PACS components and HIS, the MIMOSA work helps by defining a reference architecture which includes an external description of the various components of a PACS, and a logical structure for assembling them. 2) The model and the implementation of a demonstrator based on this model allow the relevance of the Digital Imaging and Communications in Medicine (DICOM) standard with respect to image management issues to be assessed, highlighting some current limitations of this standard and proposing extensions. Such a twofold action is necessary in order both to bring solutions, even partial, in the short term, and to allow for the convergence, in the long term, of the standards developed by independent standardization groups in medical informatics (e.g., those within Technical Committee 251 of CEN: Comité Européen de Normalisation). PMID:9617908

  8. Visual perception studies and observer models in medical imaging.

    PubMed

    Burgess, Arthur E

    2011-11-01

    Most academic radiologists will be familiar with receiver operating characteristic (ROC) studies. Fundamental studies of human observer performance are now usually performed by forced-choice methods. Both methods are based on signal detection theory. The ROC method gives an operating curve of true-positive versus false-positive probabilities. The area under the curve, A(Z), can be used a summary performance measure. In the forced-choice method, observers are given 2 or more images with one containing the signal. The observer's task is to select the option most likely to contain the signal. The percentage of correct responses, PC, is a summary performance measure. Precise comparison of the 2 methods is limited to very controlled experiments in which signals (simulated lesions for example) are carefully designed and detection or discrimination is limited by true random noise. Under these conditions, theory predicts a simple relationship between summary measures and human results are consistent with theory. There will be a description of forced-choice experimental methods and data analysis. There has also been considerable work on development of theoretic observer models. Human experiment results have used to evaluate the models. Models that correlate well with human performance in turn can be used for preliminary design of new imaging systems and for selection of image quality metrics for comparing equipment performance, this article will provide a summary of work during the last 30 years on evaluating human signal detection capabilities, observer models and image quality metrics. PMID:21978445

  9. Bashing Positivism and Reversing a Medical Model under the Guise of Evidence

    ERIC Educational Resources Information Center

    Wampold, Bruce E.

    2003-01-01

    In her advocacy of a model to train counseling psychologists as "evidence-based practitioners," Chwalisz (2003) (this issue) criticizes research based on positivism and advocates for methodological pluralism but ironically suggests the adoption of a medical model to influence the discourse on practice. In this comment, the author examines (a)…

  10. Two Models for Implementing Senior Mentor Programs in Academic Medical Settings

    ERIC Educational Resources Information Center

    Corwin, Sara J.; Bates, Tovah; Cohan, Mary; Bragg, Dawn S.; Roberts, Ellen

    2007-01-01

    This paper compares two models of undergraduate geriatric medical education utilizing senior mentoring programs. Descriptive, comparative multiple-case study was employed analyzing program documents, archival records, and focus group data. Themes were compared for similarities and differences between the two program models. Findings indicate that…

  11. Applying the International Medical Graduate Program Model to Alleviate the Supply Shortage of Accounting Doctoral Faculty

    ERIC Educational Resources Information Center

    HassabElnaby, Hassan R.; Dobrzykowski, David D.; Tran, Oanh Thikie

    2012-01-01

    Accounting has been faced with a severe shortage in the supply of qualified doctoral faculty. Drawing upon the international mobility of foreign scholars and the spirit of the international medical graduate program, this article suggests a model to fill the demand in accounting doctoral faculty. The underlying assumption of the suggested model is…

  12. The Rasch Model: Its Use by the National Board of Medical Examiners.

    ERIC Educational Resources Information Center

    Kelley, Paul R.; Schumacher, Charles F.

    1984-01-01

    The National Board of Medical Examiners uses the Rasch model to calibrate test items, maintain item banks, equate scores, and monitor the consistency of examiner item response patterns. The model is also being used in the study of patient management problems examinations, standard-setting, and computer-based examinations. (Author/BS)

  13. Problem-Based Learning: Modifying the Medical School Model for Teaching High School Economics.

    ERIC Educational Resources Information Center

    Maxwell, Nan L.; Bellisimo, Yolanda; Mergendoller, John

    2001-01-01

    Provides background information on the problem-based learning (PBL) model used in medical education that was adapted for high school economics. Describes the high school economics curriculum and outline the stages of the PBL model using examples from a unit called "The High School Food Court." Discusses the design considerations. (CMK)

  14. Construction of 3-Dimensional Printed Ultrasound Phantoms With Wall-less Vessels.

    PubMed

    Nikitichev, Daniil I; Barburas, Anamaria; McPherson, Kirstie; Mari, Jean-Martial; West, Simeon J; Desjardins, Adrien E

    2016-06-01

    Ultrasound phantoms are invaluable as training tools for vascular access procedures. We developed ultrasound phantoms with wall-less vessels using 3-dimensional printed chambers. Agar was used as a soft tissue-mimicking material, and the wall-less vessels were created with rods that were retracted after the agar was set. The chambers had integrated luer connectors to allow for fluid injections with clinical syringes. Several variations on this design are presented, which include branched and stenotic vessels. The results show that 3-dimensional printing can be well suited to the construction of wall-less ultrasound phantoms, with designs that can be readily customized and shared electronically. PMID:27162278

  15. 3-Dimensional Terraced NAND (3D TNAND) Flash Memory-Stacked Version of Folded NAND Array

    NASA Astrophysics Data System (ADS)

    Kim, Yoon; Cho, Seongjae; Lee, Gil Sung; Park, Il Han; Lee, Jong Duk; Shin, Hyungcheol; Park, Byung-Gook

    We propose a 3-dimensional terraced NAND flash memory. It has a vertical channel so it is possible to make a long enough channel in 1F2 size. And it has 3-dimensional structure whose channel is connected vertically along with two stairs. So we can obtain high density as in the stacked array structure, without silicon stacking process. We can make NAND flash memory with 3F2 cell size. Using SILVACO ATLAS simulation, we study terraced NAND flash memory characteristics such as program, erase, and read. Also, its fabrication method is proposed.

  16. Magnetic topologies of coronal mass ejection events: Effects of 3-dimensional reconnection

    SciTech Connect

    Gosling, J.T.

    1995-09-01

    New magnetic loops formed in the corona following coronal mass ejection, CME, liftoffs provide strong evidence that magnetic reconnection commonly occurs within the magnetic ``legs`` of the departing CMEs. Such reconnection is inherently 3-dimensional and naturally produces CMEs having magnetic flux rope topologies. Sustained reconnection behind CMEs can produce a mixture of open and disconnected field lines threading the CMES. In contrast to the results of 2-dimensional reconnection. the disconnected field lines are attached to the outer heliosphere at both ends. A variety of solar and solar wind observations are consistent with the concept of sustained 3-dimensional reconnection within the magnetic legs of CMEs close to the Sun.

  17. Dosimetric Comparison Between 3-Dimensional Conformal and Robotic SBRT Treatment Plans for Accelerated Partial Breast Radiotherapy.

    PubMed

    Goggin, L M; Descovich, M; McGuinness, C; Shiao, S; Pouliot, J; Park, C

    2016-06-01

    Accelerated partial breast irradiation is an attractive alternative to conventional whole breast radiotherapy for selected patients. Recently, CyberKnife has emerged as a possible alternative to conventional techniques for accelerated partial breast irradiation. In this retrospective study, we present a dosimetric comparison between 3-dimensional conformal radiotherapy plans and CyberKnife plans using circular (Iris) and multi-leaf collimators. Nine patients who had undergone breast-conserving surgery followed by whole breast radiation were included in this retrospective study. The CyberKnife planning target volume (PTV) was defined as the lumpectomy cavity + 10 mm + 2 mm with prescription dose of 30 Gy in 5 fractions. Two sets of 3-dimensional conformal radiotherapy plans were created, one used the same definitions as described for CyberKnife and the second used the RTOG-0413 definition of the PTV: lumpectomy cavity + 15 mm + 10 mm with prescription dose of 38.5 Gy in 10 fractions. Using both PTV definitions allowed us to compare the dose delivery capabilities of each technology and to evaluate the advantage of CyberKnife tracking. For the dosimetric comparison using the same PTV margins, CyberKnife and 3-dimensional plans resulted in similar tumor coverage and dose to critical structures, with the exception of the lung V5%, which was significantly smaller for 3-dimensional conformal radiotherapy, 6.2% when compared to 39.4% for CyberKnife-Iris and 17.9% for CyberKnife-multi-leaf collimator. When the inability of 3-dimensional conformal radiotherapy to track motion is considered, the result increased to 25.6%. Both CyberKnife-Iris and CyberKnife-multi-leaf collimator plans demonstrated significantly lower average ipsilateral breast V50% (25.5% and 24.2%, respectively) than 3-dimensional conformal radiotherapy (56.2%). The CyberKnife plans were more conformal but less homogeneous than the 3-dimensional conformal radiotherapy plans. Approximately 50% shorter

  18. Quantitative Modeling of Cerenkov Light Production Efficiency from Medical Radionuclides

    PubMed Central

    Beattie, Bradley J.; Thorek, Daniel L. J.; Schmidtlein, Charles R.; Pentlow, Keith S.; Humm, John L.; Hielscher, Andreas H.

    2012-01-01

    There has been recent and growing interest in applying Cerenkov radiation (CR) for biological applications. Knowledge of the production efficiency and other characteristics of the CR produced by various radionuclides would help in accessing the feasibility of proposed applications and guide the choice of radionuclides. To generate this information we developed models of CR production efficiency based on the Frank-Tamm equation and models of CR distribution based on Monte-Carlo simulations of photon and β particle transport. All models were validated against direct measurements using multiple radionuclides and then applied to a number of radionuclides commonly used in biomedical applications. We show that two radionuclides, Ac-225 and In-111, which have been reported to produce CR in water, do not in fact produce CR directly. We also propose a simple means of using this information to calibrate high sensitivity luminescence imaging systems and show evidence suggesting that this calibration may be more accurate than methods in routine current use. PMID:22363636

  19. Quantitative modeling of Cerenkov light production efficiency from medical radionuclides.

    PubMed

    Beattie, Bradley J; Thorek, Daniel L J; Schmidtlein, Charles R; Pentlow, Keith S; Humm, John L; Hielscher, Andreas H

    2012-01-01

    There has been recent and growing interest in applying Cerenkov radiation (CR) for biological applications. Knowledge of the production efficiency and other characteristics of the CR produced by various radionuclides would help in accessing the feasibility of proposed applications and guide the choice of radionuclides. To generate this information we developed models of CR production efficiency based on the Frank-Tamm equation and models of CR distribution based on Monte-Carlo simulations of photon and β particle transport. All models were validated against direct measurements using multiple radionuclides and then applied to a number of radionuclides commonly used in biomedical applications. We show that two radionuclides, Ac-225 and In-111, which have been reported to produce CR in water, do not in fact produce CR directly. We also propose a simple means of using this information to calibrate high sensitivity luminescence imaging systems and show evidence suggesting that this calibration may be more accurate than methods in routine current use. PMID:22363636

  20. A General Fuzzy Cerebellar Model Neural Network Multidimensional Classifier Using Intuitionistic Fuzzy Sets for Medical Identification.

    PubMed

    Zhao, Jing; Lin, Lo-Yi; Lin, Chih-Min

    2016-01-01

    The diversity of medical factors makes the analysis and judgment of uncertainty one of the challenges of medical diagnosis. A well-designed classification and judgment system for medical uncertainty can increase the rate of correct medical diagnosis. In this paper, a new multidimensional classifier is proposed by using an intelligent algorithm, which is the general fuzzy cerebellar model neural network (GFCMNN). To obtain more information about uncertainty, an intuitionistic fuzzy linguistic term is employed to describe medical features. The solution of classification is obtained by a similarity measurement. The advantages of the novel classifier proposed here are drawn out by comparing the same medical example under the methods of intuitionistic fuzzy sets (IFSs) and intuitionistic fuzzy cross-entropy (IFCE) with different score functions. Cross verification experiments are also taken to further test the classification ability of the GFCMNN multidimensional classifier. All of these experimental results show the effectiveness of the proposed GFCMNN multidimensional classifier and point out that it can assist in supporting for correct medical diagnoses associated with multiple categories. PMID:27298619

  1. A General Fuzzy Cerebellar Model Neural Network Multidimensional Classifier Using Intuitionistic Fuzzy Sets for Medical Identification

    PubMed Central

    Zhao, Jing; Lin, Lo-Yi

    2016-01-01

    The diversity of medical factors makes the analysis and judgment of uncertainty one of the challenges of medical diagnosis. A well-designed classification and judgment system for medical uncertainty can increase the rate of correct medical diagnosis. In this paper, a new multidimensional classifier is proposed by using an intelligent algorithm, which is the general fuzzy cerebellar model neural network (GFCMNN). To obtain more information about uncertainty, an intuitionistic fuzzy linguistic term is employed to describe medical features. The solution of classification is obtained by a similarity measurement. The advantages of the novel classifier proposed here are drawn out by comparing the same medical example under the methods of intuitionistic fuzzy sets (IFSs) and intuitionistic fuzzy cross-entropy (IFCE) with different score functions. Cross verification experiments are also taken to further test the classification ability of the GFCMNN multidimensional classifier. All of these experimental results show the effectiveness of the proposed GFCMNN multidimensional classifier and point out that it can assist in supporting for correct medical diagnoses associated with multiple categories. PMID:27298619

  2. A Review of 21st Century Utility of a Biopsychosocial Model in United States Medical School Education

    PubMed Central

    Jaini, Paresh Atu; Lee, Jenny Seung-Hyun

    2015-01-01

    Background Current medical practice is grounded in a biomedical model that fails to effectively address multifaceted lifestyle and morbidogenic environmental components that are the root causes of contemporary chronic diseases. Utilizing the biopsychosocial (BPS) model in medical school training may produce competent healthcare providers to meet the challenge of rising chronic illnesses that are a result of these factors. This study explored the current trend of research on the utility of the BPS model in medical education and examined medical school curricula that have explicitly adopted the BPS model. Methods A systematic review of peer-reviewed literature was conducted on the BPS model and medical education since the 1970s using multiple databases. Descriptive analysis was used to illustrate findings regarding the trends of the BPS model in medical education and its utility in specific medical schools in the United States. Results Major findings illustrated a growing trend in research on the BPS model in medical education since the 1970s with literature in this area most visible since 2000. The same trend was established for the incorporation of psychosocial or behavioral and social science components in medical education. From our peer-reviewed literature search, only 5 medical schools featured utility of the BPS model in their curricula utilizing variable educational processes. Conclusion Although literature regarding the BPS model in medical education is growing, the explicit utility of the BPS model in medical school is limited. Our findings can stimulate educational processes and research endeavors to advance medical education and medical practice to ensure that future doctors can meet the challenge of rising lifestyle and environmental associated illnesses. PMID:26770891

  3. Oxidation behavior of ammonium in a 3-dimensional biofilm-electrode reactor.

    PubMed

    Tang, Jinjing; Guo, Jinsong; Fang, Fang; Chen, Youpeng; Lei, Lijing; Yang, Lin

    2013-12-01

    Excess nitrogenous compounds are detrimental to natural water systems and to human health. To completely realize autohydrogenotrophic nitrogen removal, a novel 3-dimensional biofilm-electrode reactor was designed. Titanium was electroplated with ruthenium and used as the anode. Activated carbon fiber felt was used as the cathode. The reactor was separated into two chambers by a permeable membrane. The cathode chamber was filled with granular graphite and glass beads. The cathode and cathode chamber were inhabited with domesticated biofilm. In the absence of organic substances, a nitrogen removal efficiency of up to 91% was achieved at DO levels of 3.42 +/- 0.37 mg/L when the applied current density was only 0.02 mA/cm2. The oxidation of ammonium in biofilm-electrode reactors was also investigated. It was found that ammonium could be oxidized not only on the anode but also on particle electrodes in the cathode chamber of the biofilm-electrode reactor. Oxidation rates of ammonium and nitrogen removal efficiency were found to be affected by the electric current loading on the biofilm-electrode reactor. The kinetic model of ammonium at different electric currents was analyzed by a first-order reaction kinetics equation. The regression analysis implied that when the current density was less than 0.02 mA/cm2, ammonium removal was positively correlated to the current density. However, when the current density was more than 0.02 mA/cm2, the electric current became a limiting factor for the oxidation rate of ammonium and nitrogen removal efficiency. PMID:24649670

  4. Reconstruction 3-dimensional image from 2-dimensional image of status optical coherence tomography (OCT) for analysis of changes in retinal thickness

    SciTech Connect

    Arinilhaq,; Widita, Rena

    2014-09-30

    Optical Coherence Tomography is often used in medical image acquisition to diagnose that change due easy to use and low price. Unfortunately, this type of examination produces a two-dimensional retinal image of the point of acquisition. Therefore, this study developed a method that combines and reconstruct 2-dimensional retinal images into three-dimensional images to display volumetric macular accurately. The system is built with three main stages: data acquisition, data extraction and 3-dimensional reconstruction. At data acquisition step, Optical Coherence Tomography produced six *.jpg images of each patient were further extracted with MATLAB 2010a software into six one-dimensional arrays. The six arrays are combined into a 3-dimensional matrix using a kriging interpolation method with SURFER9 resulting 3-dimensional graphics of macula. Finally, system provides three-dimensional color graphs based on the data distribution normal macula. The reconstruction system which has been designed produces three-dimensional images with size of 481 × 481 × h (retinal thickness) pixels.

  5. Developing Physiologic Models for Emergency Medical Procedures Under Microgravity

    NASA Technical Reports Server (NTRS)

    Parker, Nigel; O'Quinn, Veronica

    2012-01-01

    Several technological enhancements have been made to METI's commercial Emergency Care Simulator (ECS) with regard to how microgravity affects human physiology. The ECS uses both a software-only lung simulation, and an integrated mannequin lung that uses a physical lung bag for creating chest excursions, and a digital simulation of lung mechanics and gas exchange. METI s patient simulators incorporate models of human physiology that simulate lung and chest wall mechanics, as well as pulmonary gas exchange. Microgravity affects how O2 and CO2 are exchanged in the lungs. Procedures were also developed to take into affect the Glasgow Coma Scale for determining levels of consciousness by varying the ECS eye-blinking function to partially indicate the level of consciousness of the patient. In addition, the ECS was modified to provide various levels of pulses from weak and thready to hyper-dynamic to assist in assessing patient conditions from the femoral, carotid, brachial, and pedal pulse locations.

  6. Developing Physiologic Models for Emergency Medical Procedures Under Microgravity

    NASA Technical Reports Server (NTRS)

    Parker, Nigel; OQuinn, Veronica

    2012-01-01

    Several technological enhancements have been made to METI's commercial Emergency Care Simulator (ECS) with regard to how microgravity affects human physiology. The ECS uses both a software-only lung simulation, and an integrated mannequin lung that uses a physical lung bag for creating chest excursions, and a digital simulation of lung mechanics and gas exchange. METI's patient simulators incorporate models of human physiology that simulate lung and chest wall mechanics, as well as pulmonary gas exchange. Microgravity affects how O2 and CO2 are exchanged in the lungs. Procedures were also developed to take into affect the Glasgow Coma Scale for determining levels of consciousness by varying the ECS eye-blinking function to partially indicate the level of consciousness of the patient. In addition, the ECS was modified to provide various levels of pulses from weak and thready to hyper-dynamic to assist in assessing patient conditions from the femoral, carotid, brachial, and pedal pulse locations.

  7. 3-dimensional root phenotyping with a novel imaging and software platform

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A novel imaging and software platform was developed for the high-throughput phenotyping of 3-dimensional root traits during seedling development. To demonstrate the platform’s capacity, plants of two rice (Oryza sativa) genotypes, Azucena and IR64, were grown in a transparent gellan gum system and ...

  8. 3-DIMENSIONAL MEASURED AND SIMULATED FLOW FOR SCOUR NEAR SPUR DIKES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To improve understanding of the flow and scour processes associated with spur dikes more fully, 3-dimensional flow velocities were measured using an acoustic Doppler velocimeter at a closely spaced grid over a fixed flat bed with a submerged spur dike. Some 2592 three-dimensional velocities around a...

  9. Characterization of Students' Reasoning and Proof Abilities in 3-Dimensional Geometry

    ERIC Educational Resources Information Center

    Gutierrez, Angel; Pegg, John; Lawrie, Christine

    2004-01-01

    In this paper we report on a research aimed to identify and characterize secondary school students' reasoning and proof abilities when working with 3-dimensional geometric solids. We analyze students' answers to two problems asking them to prove certain properties of prisms. As results of this analysis, we get, on the one side, a characterization…

  10. 3-Dimensional and Interactive Istanbul University Virtual Laboratory Based on Active Learning Methods

    ERIC Educational Resources Information Center

    Ince, Elif; Kirbaslar, Fatma Gulay; Yolcu, Ergun; Aslan, Ayse Esra; Kayacan, Zeynep Cigdem; Alkan Olsson, Johanna; Akbasli, Ayse Ceylan; Aytekin, Mesut; Bauer, Thomas; Charalambis, Dimitris; Gunes, Zeliha Ozsoy; Kandemir, Ceyhan; Sari, Umit; Turkoglu, Suleyman; Yaman, Yavuz; Yolcu, Ozgu

    2014-01-01

    The purpose of this study is to develop a 3-dimensional interactive multi-user and multi-admin IUVIRLAB featuring active learning methods and techniques for university students and to introduce the Virtual Laboratory of Istanbul University and to show effects of IUVIRLAB on students' attitudes on communication skills and IUVIRLAB. Although…

  11. Expanding clinical medical training opportunities at the University of Nairobi: adapting a regional medical education model from the WWAMI program at the University of Washington.

    PubMed

    Child, Mara J; Kiarie, James N; Allen, Suzanne M; Nduati, Ruth; Wasserheit, Judith N; Kibore, Minnie W; John-Stewart, Grace; Njiri, Francis J; O'Malley, Gabrielle; Kinuthia, Raphael; Norris, Tom E; Farquhar, Carey

    2014-08-01

    A major medical education need in Sub-Saharan Africa includes expanding clinical training opportunities to develop health professionals. Medical education expansion is a complicated process that requires significant investment of financial and human resources, but it can also provide opportunities for innovative approaches and partnerships. In 2010, the U.S. President's Emergency Plan for AIDS Relief launched the Medical Education Partnership Initiative to invest in medical education and health system strengthening in Africa. Building on a 30-year collaborative clinical and research training partnership, the University of Nairobi in Kenya developed a pilot regional medical education program modeled on the WWAMI (Washington, Wyoming, Alaska, Montana, and Idaho) medical education program at the University of Washington in the United States. The University of Nairobi adapted key elements of the WWAMI model to expand clinical training opportunities without requiring major capital construction of new buildings or campuses. The pilot program provides short-term clinical training opportunities for undergraduate students and recruits and trains clinical faculty at 14 decentralized training sites. The adaptation of a model from the Northwestern United States to address medical education needs in Kenya is a successful transfer of knowledge and practices that can be scaled up and replicated across Sub-Saharan Africa. PMID:25072575

  12. Expanding Clinical Medical Training Opportunities at the University of Nairobi: Adapting a Regional Medical Education Model from the WWAMI Program at the University of Washington

    PubMed Central

    Child, Mara J.; Kiarie, James N.; Allen, Suzanne M.; Nduati, Ruth; Wasserheit, Judith N.; Kibore, Minnie W.; John-Stewart, Grace; Njiri, Francis J.; O'Malley, Gabrielle; Kinuthia, Raphael; Norris, Tom E.; Farquhar, Carey

    2014-01-01

    A major medical education need in Sub-Saharan Africa includes expanding clinical training opportunities to develop health professionals. Medical education expansion is a complicated process that requires significant investment of financial and human resources, but it can also provide opportunities for innovative approaches and partnerships. In 2010, the U.S. President's Emergency Plan for AIDS Relief (PEPFAR) launched the Medical Education Partnership Initiative to invest in medical education and health system strengthening in Africa. Building on a 30-year collaborative clinical and research training partnership, the University of Nairobi in Kenya developed a pilot regional medical education program modeled on the WWAMI (Washington, Wyoming, Alaska, Montana, and Idaho) medical education program at the University of Washington in the United States. The University of Nairobi adapted key elements of the WWAMI model to expand clinical training opportunities without requiring major capital construction of new buildings or campuses. The pilot program provides short-term clinical training opportunities for undergraduate students and recruits and trains clinical faculty at 14 decentralized training sites. The adaptation of a model from the Northwestern United States to address medical education needs in Kenya is a successful transfer of knowledge and practices that can be scaled up and replicated across Sub-Saharan Africa. PMID:25072575

  13. Gender perspective in medicine: a vital part of medical scientific rationality. A useful model for comprehending structures and hierarchies within medical science

    PubMed Central

    Risberg, Gunilla; Hamberg, Katarina; Johansson, Eva E

    2006-01-01

    Background During the past few decades, research has reported gender bias in various areas of clinical and academic medicine. To prevent such bias, a gender perspective in medicine has been requested, but difficulties and resistance have been reported from implementation attempts. Our study aimed at analysing this resistance in relation to what is considered good medical research. Method We used a theoretical model, based on scientific competition, to understand the structures of scientific medicine and how they might influence the resistance to a gender perspective in medicine. The model was originally introduced to discuss how pluralism improves rationality in the social sciences. Results The model provided a way to conceptualise different fields of research in medicine: basic research, applied research, medical philosophy, and 'empowering' research. It clarified how various research approaches within medicine relate to each other, and how they differ and compete. It also indicated why there might be conflicts between them: basic and applied research performed within the biomedical framework have higher status than gender research and other research approaches that are performed within divergent research paradigms. Conclusion This hierarchy within medical research contributes to the resistance to a gender perspective, causing gender bias and making medical scientific rationality suboptimal. We recommend that the theoretical model can be applied in a wider medical context when different and hierarchically arranged research traditions are in conflict. In this way, the model might contribute to shape a medical community where scientific pluralism is acknowledged to enlarge, not to disturb, the scientific rationality of medicine. PMID:16928283

  14. Prairie Voles as a Model to Screen Medications for the Treatment of Alcoholism and Addictions.

    PubMed

    Ryabinin, A E; Hostetler, C M

    2016-01-01

    Most preclinical studies of medications to treat addictions are performed in mice and rats. These two rodent species belong to one phylogenetic subfamily, which narrows the likelihood of identifying potential mechanisms regulating addictions in other species, ie, humans. Expanding the genetic diversity of organisms modeling alcohol and drug abuse enhances our ability to screen for medications to treat addiction. Recently, research laboratories adapted the prairie vole model to study mechanisms of alcohol and drugs of abuse. This development not only expanded the diversity of genotypes used to screen medications, but also enhanced capabilities of such screens. Prairie voles belong to 3-5% of mammalian species exhibiting social monogamy. This unusual trait is reflected in their ability to form lasting long-term affiliations between adult individuals. The prairie vole animal model has high predictive validity for mechanisms regulating human social behaviors. In addition, these animals exhibit high alcohol intake and preference. In laboratory settings, prairie voles are used to model social influences on drug reward and alcohol consumption as well as effects of addictive substances on social bonding. As a result, this species can be adapted to screen medications whose effectiveness could be (a) resistant to social influences promoting excessive drug taking, (b) dependent on the presence of social support, and (c) medications affecting harmful social consequences of alcohol and drug abuse. This report reviews the literature on studies of alcohol and psychostimulants in prairie voles and discusses capabilities of this animal model as a screen for novel medications to treat alcoholism and addictions. PMID:27055620

  15. The Integrated Medical Model: Statistical Forecasting of Risks to Crew Health and Mission Success

    NASA Technical Reports Server (NTRS)

    Fitts, M. A.; Kerstman, E.; Butler, D. J.; Walton, M. E.; Minard, C. G.; Saile, L. G.; Toy, S.; Myers, J.

    2008-01-01

    The Integrated Medical Model (IMM) helps capture and use organizational knowledge across the space medicine, training, operations, engineering, and research domains. The IMM uses this domain knowledge in the context of a mission and crew profile to forecast crew health and mission success risks. The IMM is most helpful in comparing the risk of two or more mission profiles, not as a tool for predicting absolute risk. The process of building the IMM adheres to Probability Risk Assessment (PRA) techniques described in NASA Procedural Requirement (NPR) 8705.5, and uses current evidence-based information to establish a defensible position for making decisions that help ensure crew health and mission success. The IMM quantitatively describes the following input parameters: 1) medical conditions and likelihood, 2) mission duration, 3) vehicle environment, 4) crew attributes (e.g. age, sex), 5) crew activities (e.g. EVA's, Lunar excursions), 6) diagnosis and treatment protocols (e.g. medical equipment, consumables pharmaceuticals), and 7) Crew Medical Officer (CMO) training effectiveness. It is worth reiterating that the IMM uses the data sets above as inputs. Many other risk management efforts stop at determining only likelihood. The IMM is unique in that it models not only likelihood, but risk mitigations, as well as subsequent clinical outcomes based on those mitigations. Once the mathematical relationships among the above parameters are established, the IMM uses a Monte Carlo simulation technique (a random sampling of the inputs as described by their statistical distribution) to determine the probable outcomes. Because the IMM is a stochastic model (i.e. the input parameters are represented by various statistical distributions depending on the data type), when the mission is simulated 10-50,000 times with a given set of medical capabilities (risk mitigations), a prediction of the most probable outcomes can be generated. For each mission, the IMM tracks which conditions

  16. Water uptake by a maize root system - An explicit numerical 3-dimensional simulation.

    NASA Astrophysics Data System (ADS)

    Leitner, Daniel; Schnepf, Andrea; Klepsch, Sabine; Roose, Tiina

    2010-05-01

    Water is one of the most important resources for plant growth and function. An accurate modelling of the unsaturated flow is not only substantial to predict water uptake but also important to describe nutrient movement regarding water saturation and transport. In this work we present a model for water uptake. The model includes the simultaneous flow of water inside the soil and inside the root network. Water saturation in the soil volume is described by the Richards equation. Water flow inside the roots' xylem is calculated using the Poiseuille law for water flow in a cylindrical tube. The water saturation in the soil as well as water uptake of the root system is calculated numerically in three dimensions. We study water uptake of a maize plant in a confined pot under different supply scenarios. The main improvement of our approach is that the root surfaces act as spatial boundaries of the soil volume. Therefore water influx into the root is described by a surface flux instead of a volume flux, which is commonly given by an effective sink term. For the numerical computation we use the following software: The 3-dimensional maize root architecture is created by a root growth model based on L-Systems (Leitner et al 2009). A mesh of the surrounding soil volume is created using the meshing software DistMesh (Persson & Strang 2004). Using this mesh the partial differential equations are solved with the finite element method using Comsol Multiphysics 3.5a. Modelling results are related to accepted water uptake models from literature (Clausnitzer & Hopmans 1994, Roose & Fowler 2004, Javaux et al 2007). This new approach has several advantages. By considering the individual roots it is possible to analyse the influence of overlapping depletion zones due to inter root competition. Furthermore, such simulations can be used to estimate the influence of simplifying assumptions that are made in the development of effective models. The model can be easily combined with a nutrient

  17. Clinical Prediction Models for Sleep Apnea: The Importance of Medical History over Symptoms

    PubMed Central

    Ustun, Berk; Westover, M. Brandon; Rudin, Cynthia; Bianchi, Matt T.

    2016-01-01

    Study Objective: Obstructive sleep apnea (OSA) is a treatable contributor to morbidity and mortality. However, most patients with OSA remain undiagnosed. We used a new machine learning method known as SLIM (Supersparse Linear Integer Models) to test the hypothesis that a diagnostic screening tool based on routinely available medical information would be superior to one based solely on patient-reported sleep-related symptoms. Methods: We analyzed polysomnography (PSG) and self-reported clinical information from 1,922 patients tested in our clinical sleep laboratory. We used SLIM and 7 state-of-the-art classification methods to produce predictive models for OSA screening using features from: (i) self-reported symptoms; (ii) self-reported medical information that could, in principle, be extracted from electronic health records (demographics, comorbidities), or (iii) both. Results: For diagnosing OSA, we found that model performance using only medical history features was superior to model performance using symptoms alone, and similar to model performance using all features. Performance was similar to that reported for other widely used tools: sensitivity 64.2% and specificity 77%. SLIM accuracy was similar to state-of-the-art classification models applied to this dataset, but with the benefit of full transparency, allowing for hands-on prediction using yes/no answers to a small number of clinical queries. Conclusion: To predict OSA, variables such as age, sex, BMI, and medical history are superior to the symptom variables we examined for predicting OSA. SLIM produces an actionable clinical tool that can be applied to data that is routinely available in modern electronic health records, which may facilitate automated, rather than manual, OSA screening. Commentary: A commentary on this article appears in this issue on page 159. Citation: Ustun B, Westover MB, Rudin C, Bianchi MT. Clinical prediction models for sleep apnea: the importance of medical history over symptoms

  18. The Inflammatory Bowel Disease Specialty Medical Home: A New Model of Patient-centered Care.

    PubMed

    Regueiro, Miguel D; McAnallen, Sandra E; Greer, Julia B; Perkins, Stephen E; Ramalingam, S; Szigethy, Eva

    2016-08-01

    New models of health care have emerged over the past decade. Accountable care organizations and patient-centered medical homes are designed to improve the patient experience, enhance health care quality, and decrease cost. These models have been developed in the primary care domain and have yet to be tested in specialty care. Certain chronic diseases require principal care by a specialist or health care team. The specialty medical home would provide patient-centered care for specific populations of patients whose health care derives from a single chronic disease. This article defines the parameters for a specialty medical home and provides a specific payer-provider experience for the comprehensive care of an inflammatory bowel disease population. PMID:27135486

  19. Project EASE: a study to test a psychosocial model of epilepsy medication managment.

    PubMed

    DiIorio, Collen; Shafer, Patricia Osborne; Letz, Richard; Henry, Thomas R; Schomer, Donal L; Yeager, Kate

    2004-12-01

    The purpose of this study was to test a psychosocial model of medication self-management among people with epilepsy. This model was based primarily on social cognitive theory and included personal (self-efficacy, outcome expectations, goals, stigma, and depressive symptoms), social (social support), and provider (patient satisfaction and desire for control) variables. Participants for the study were enrolled at research sites in Atlanta, Georgia, and Boston, Massachusetts and completed computer-based assessments that included measures of the study variables listed above. The mean age of the 317 participants was 43.3 years; about 50% were female, and 81%white. Self-efficacy and patient satisfaction explained the most variance in medication management. Social support was related to self-efficacy; stigma to self-efficacy and depressive symptoms; and self-efficacy to outcome expectations and depressive symptoms. Findings reinforce that medication-taking behavior is affected by a complex set of interactions among psychosocial variables. PMID:15624235

  20. A Model-Based Approach to Support Validation of Medical Cyber-Physical Systems.

    PubMed

    Silva, Lenardo C; Almeida, Hyggo O; Perkusich, Angelo; Perkusich, Mirko

    2015-01-01

    Medical Cyber-Physical Systems (MCPS) are context-aware, life-critical systems with patient safety as the main concern, demanding rigorous processes for validation to guarantee user requirement compliance and specification-oriented correctness. In this article, we propose a model-based approach for early validation of MCPS, focusing on promoting reusability and productivity. It enables system developers to build MCPS formal models based on a library of patient and medical device models, and simulate the MCPS to identify undesirable behaviors at design time. Our approach has been applied to three different clinical scenarios to evaluate its reusability potential for different contexts. We have also validated our approach through an empirical evaluation with developers to assess productivity and reusability. Finally, our models have been formally verified considering functional and safety requirements and model coverage. PMID:26528982

  1. A Model-Based Approach to Support Validation of Medical Cyber-Physical Systems

    PubMed Central

    Silva, Lenardo C.; Almeida, Hyggo O.; Perkusich, Angelo; Perkusich, Mirko

    2015-01-01

    Medical Cyber-Physical Systems (MCPS) are context-aware, life-critical systems with patient safety as the main concern, demanding rigorous processes for validation to guarantee user requirement compliance and specification-oriented correctness. In this article, we propose a model-based approach for early validation of MCPS, focusing on promoting reusability and productivity. It enables system developers to build MCPS formal models based on a library of patient and medical device models, and simulate the MCPS to identify undesirable behaviors at design time. Our approach has been applied to three different clinical scenarios to evaluate its reusability potential for different contexts. We have also validated our approach through an empirical evaluation with developers to assess productivity and reusability. Finally, our models have been formally verified considering functional and safety requirements and model coverage. PMID:26528982

  2. A Structural Model of Stress, Motivation, and Academic Performance in Medical Students

    PubMed Central

    Park, Jangho; An, Hoyoung; Park, Seungjin; Lee, Chul; Kim, Seong Yoon; Lee, Jae-Dam; Kim, Ki-Soo

    2012-01-01

    Objective The purpose of the present study was 1) to identify factors that may influence academic stress in medical students and 2) to investigate the causal relationships among these variables with path analysis. Methods One hundred sixty medical students participated in the present study. Psychological parameters were assessed with the Medical Stress Scale, Minnesota Multiphasic Personality Inventory, Hamilton Depression Scale, Beck Depression Inventory, and Academic Motivation Scale. Linear regression and path analysis were used to examine the relationships among variables. Results Significant correlations were noted between several factors and Medical Stress scores. Specifically, Hamilton Depression Scale scores (β=0.26, p=0.03) and amotivation (β=0.20, p=0.01) and extrinsically identified regulation (β=0.27, p<0.01) response categories on the Academic Motivation Scale had independent and significant influences on Medical Stress Scale scores. A path analysis model indicated that stress, motivation, and academic performance formed a triangular feedback loop. Moreover, depression was associated with both stress and motivation, and personality was associated with motivation. Conclusion The triangular feedback-loop structure in the present study indicated that actions that promote motivation benefit from interventions against stress and depression. Moreover, stress management increases motivation in students. Therefore, strategies designed to reduce academic pressures in medical students should consider these factors. Additional studies should focus on the relationship between motivation and depression. PMID:22707964

  3. Home Care Learning Model for Medical Students in Chile: A Mixed Methods Study

    PubMed Central

    Gonzalez, Carolina

    2014-01-01

    Introduction. The relevance of home care training is not questioned. However, there are no reported learning models to teach in this setting. Aims. To develop and evaluate a learning model to teach home care to medical students. Methods. Stage 1: Learning Model Design. Tutors teaching home care and a sample of medical students were invited to focus groups analyzed according to the grounded theory. Later, the researchers designed the learning model, which was approved by all participants. Stage 2: Learning Assessment. All students in their family medicine internship at Pontificia Universidad Catolica de Chile were invited to participate in a nonrandomized before-and-after pilot trial, assessing changes in their perception towards home care and satisfaction with the learning model. Results. Stage 1: Six tutors and eight students participated in the focus groups. The learning model includes activities before, during, and after the visits. Stage 2: 105 students (88.2%) participated. We observed improvement in all home care training domains (P ≤ 0.001) and a high satisfaction with the model. Students with previous home visit experiences and who participated with nurses and social workers reported more learning. Conclusions. We report an effective learning model to train medical students in home care. Limitations and recommendations for future studies are discussed. PMID:24967327

  4. A Baseline Patient Model to Support Testing of Medical Cyber-Physical Systems.

    PubMed

    Silva, Lenardo C; Perkusich, Mirko; Almeida, Hyggo O; Perkusich, Angelo; Lima, Mateus A M; Gorgônio, Kyller C

    2015-01-01

    Medical Cyber-Physical Systems (MCPS) are currently a trending topic of research. The main challenges are related to the integration and interoperability of connected medical devices, patient safety, physiologic closed-loop control, and the verification and validation of these systems. In this paper, we focus on patient safety and MCPS validation. We present a formal patient model to be used in health care systems validation without jeopardizing the patient's health. To determine the basic patient conditions, our model considers the four main vital signs: heart rate, respiratory rate, blood pressure and body temperature. To generate the vital signs we used regression models based on statistical analysis of a clinical database. Our solution should be used as a starting point for a behavioral patient model and adapted to specific clinical scenarios. We present the modeling process of the baseline patient model and show its evaluation. The conception process may be used to build different patient models. The results show the feasibility of the proposed model as an alternative to the immediate need for clinical trials to test these medical systems. PMID:26262111

  5. Evaluation of HVS models in the application of medical image quality assessment

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Cavaro-Menard, C.; Le Callet, P.

    2012-03-01

    In this study, four of the most widely used Human Visual System (HVS) models are applied on Magnetic Resonance (MR) images for signal detection task. Their performances are evaluated against gold standard derived from radiologists' majority decision. The task-based image quality assessment requires taking into account the human perception specificities, for which various HVS models have been proposed. However to our knowledge, no work was conducted to evaluate and compare the suitability of these models with respect to the assessment of medical image qualities. This pioneering study investigates the performances of different HVS models on medical images in terms of approximation to radiologist performance. We propose to score the performance of each HVS model using the AUC (Area Under the receiver operating characteristic Curve) and its variance estimate as the figure of merit. The radiologists' majority decision is used as gold standard so that the estimated AUC measures the distance between the HVS model and the radiologist perception. To calculate the variance estimate of AUC, we adopted the one-shot method that is independent of the HVS model's output range. The results of this study will help to provide arguments to the application of some HVS model on our future medical image quality assessment metric.

  6. Home care learning model for medical students in chile: a mixed methods study.

    PubMed

    Garcia-Huidobro, Diego; Rivera, Solange; Gonzalez, Carolina

    2014-01-01

    Introduction. The relevance of home care training is not questioned. However, there are no reported learning models to teach in this setting. Aims. To develop and evaluate a learning model to teach home care to medical students. Methods. Stage 1: Learning Model Design. Tutors teaching home care and a sample of medical students were invited to focus groups analyzed according to the grounded theory. Later, the researchers designed the learning model, which was approved by all participants. Stage 2: Learning Assessment. All students in their family medicine internship at Pontificia Universidad Catolica de Chile were invited to participate in a nonrandomized before-and-after pilot trial, assessing changes in their perception towards home care and satisfaction with the learning model. Results. Stage 1: Six tutors and eight students participated in the focus groups. The learning model includes activities before, during, and after the visits. Stage 2: 105 students (88.2%) participated. We observed improvement in all home care training domains (P ≤ 0.001) and a high satisfaction with the model. Students with previous home visit experiences and who participated with nurses and social workers reported more learning. Conclusions. We report an effective learning model to train medical students in home care. Limitations and recommendations for future studies are discussed. PMID:24967327

  7. Assessment of the interns’ ability based on Dundee model in Shiraz University of Medical Sciences

    PubMed Central

    AMINI, MITRA; ABIRI, SAMANEH; NABEIEI, PARISA; GHANAVATI, SHIRIN; HAYAT, ALI ASGHAR; KOJURI, JAVAD

    2015-01-01

    Introduction The importance of medical profession and the role of the physician in society is no secret to anyone. Skills and competencies in clinical practice are necessary for the medical profession. In fact, in patient care, doctors require practical skills in addition to scientific knowledge. This study examines the potentials of medical school students in three areas of doing the right thing, doing the right thing in an intermediate range, and doing the right thing by the right person. Methods This study was done in a descriptive-analytical and sectional model. The population of this study was all interns of Shiraz University of Medical Sciences who were passing internship at Internal Medicine, Surgery, Pediatrics, Obstetrics and Emergency wards. About 100 persons were selected by simple randomization. In order to collect data, a questionnaire with 12 questions was designed in two parts. The questionnaire was approved by 7 Faculty members of Clinical Medicine and Medical Education, and its reliability was approved by test-retest method on 20 medical students in the form of a pilot study and through Cronbach's alpha (82%). Collected data were analyzed by SPSS software version 14 using descriptive statistical methods. Results Results showed that within the inner circle, interns evaluated their skills in surgery, internal medicine, and gynecology wards, intermediate and at other wards as weak. Also within the center circle, interns evaluated adequate educational evidence-based training in the field of medicine, and sufficiency of educational training in the field of clinical decision making and clinical care as suitable. Conclusion According to the results, it seems that medical interns' skills in performing most medical skills are moderate. So teaching students by new educational methods and workshop techniques, using experienced teachers will be effective. The use of clinical skills training centers and objective assessment methods for the students' skills

  8. Modeling Determinants of Medication Attitudes and Poor Adherence in Early Nonaffective Psychosis: Implications for Intervention

    PubMed Central

    Drake, Richard J.; Nordentoft, Merete; Haddock, Gillian; Arango, Celso; Fleischhacker, W. Wolfgang; Glenthøj, Birte; Leboyer, Marion; Leucht, Stefan; Leweke, Markus; McGuire, Phillip; Meyer-Lindenberg, Andreas; Rujescu, Dan; Sommer, Iris E.; Kahn, René S.; Lewis, Shon W.

    2015-01-01

    We aimed to design a multimodal intervention to improve adherence following first episode psychosis, consistent with current evidence. Existing literature identified medication attitudes, insight, and characteristics of support as important determinants of adherence to medication: we examined medication attitudes, self-esteem, and insight in an early psychosis cohort better to understand their relationships. Existing longitudinal data from 309 patients with early Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, nonaffective psychosis (83% first episode) were analyzed to test the hypothesis that medication attitudes, while meaningfully different from “insight,” correlated with insight and self-esteem, and change in each influenced the others. Rosenberg Self-Esteem Scale, Birchwood Insight Scale, and Positive and Negative Syndrome Scale insight were assessed at presentation, after 6 weeks and 3 and 18 months. Drug Attitudes Inventory (DAI) and treatment satisfaction were rated from 6 weeks onward. Structural equation models of their relationships were compared. Insight measures’ and DAI’s predictive validity were compared against relapse, readmission, and remission. Analysis found five latent constructs best fitted the data: medication attitudes, self-esteem, accepting need for treatment, self-rated insight, and objective insight. All were related and each affected the others as it changed, except self-esteem and medication attitudes. Low self-reported insight at presentation predicted readmission. Good 6-week insight (unlike drug attitudes) predicted remission. Literature review and data modeling indicated that a multimodal intervention using motivational interviewing, online psychoeducation, and SMS text medication reminders to enhance adherence without damaging self-concept was feasible and appropriate. PMID:25750247

  9. Modeling determinants of medication attitudes and poor adherence in early nonaffective psychosis: implications for intervention.

    PubMed

    Drake, Richard J; Nordentoft, Merete; Haddock, Gillian; Arango, Celso; Fleischhacker, W Wolfgang; Glenthøj, Birte; Leboyer, Marion; Leucht, Stefan; Leweke, Markus; McGuire, Phillip; Meyer-Lindenberg, Andreas; Rujescu, Dan; Sommer, Iris E; Kahn, René S; Lewis, Shon W

    2015-05-01

    We aimed to design a multimodal intervention to improve adherence following first episode psychosis, consistent with current evidence. Existing literature identified medication attitudes, insight, and characteristics of support as important determinants of adherence to medication: we examined medication attitudes, self-esteem, and insight in an early psychosis cohort better to understand their relationships. Existing longitudinal data from 309 patients with early Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, nonaffective psychosis (83% first episode) were analyzed to test the hypothesis that medication attitudes, while meaningfully different from "insight," correlated with insight and self-esteem, and change in each influenced the others. Rosenberg Self-Esteem Scale, Birchwood Insight Scale, and Positive and Negative Syndrome Scale insight were assessed at presentation, after 6 weeks and 3 and 18 months. Drug Attitudes Inventory (DAI) and treatment satisfaction were rated from 6 weeks onward. Structural equation models of their relationships were compared. Insight measures' and DAI's predictive validity were compared against relapse, readmission, and remission. Analysis found five latent constructs best fitted the data: medication attitudes, self-esteem, accepting need for treatment, self-rated insight, and objective insight. All were related and each affected the others as it changed, except self-esteem and medication attitudes. Low self-reported insight at presentation predicted readmission. Good 6-week insight (unlike drug attitudes) predicted remission. Literature review and data modeling indicated that a multimodal intervention using motivational interviewing, online psychoeducation, and SMS text medication reminders to enhance adherence without damaging self-concept was feasible and appropriate. PMID:25750247

  10. What makes a top research medical school? A call for a new model to evaluate academic physicians and medical school performance.

    PubMed

    Goldstein, Matthew J; Lunn, Mitchell R; Peng, Lily

    2015-05-01

    Since the publication of the Flexner Report in 1910, the medical education enterprise has undergone many changes to ensure that medical schools meet a minimum standard for the curricula and clinical training they offer students. Although the efforts of the licensing and accrediting bodies have raised the quality of medical education, the educational processes that produce the physicians who provide the best patient care and conduct the best biomedical research have not been identified. Comparative analyses are powerful tools to understand the differences between institutions, but they are challenging to carry out. As a result, the analysis performed by U.S. News & World Report (USN&WR) has become the default tool to compare U.S. medical schools. Medical educators must explore more rigorous and equitable approaches to analyze and understand the performance of medical schools. In particular, a better understanding and more thorough evaluation of the most successful institutions in producing academic physicians with biomedical research careers are needed. In this Perspective, the authors present a new model to evaluate medical schools' production of academic physicians who advance medicine through basic, clinical, translational, and implementation science research. This model is based on relevant and accessible objective criteria that should replace the subjective criteria used in the current USN&WR rankings system. By fostering a national discussion about the most meaningful criteria that should be measured and reported, the authors hope to increase transparency of assessment standards and ultimately improve educational quality. PMID:25607941

  11. Predictive Modeling of Student Performances for Retention and Academic Support in a Diagnostic Medical Sonography Program

    ERIC Educational Resources Information Center

    Borghese, Peter; Lacey, Sandi

    2014-01-01

    As part of a retention and academic support program, data was collected to develop a predictive model of student performances in core classes in a Diagnostic Medical Sonography (DMS) program. The research goal was to identify students likely to have difficulty with coursework and provide supplemental tutorial support. The focus was on the…

  12. Integrating Geriatric Content into a Medical School Curriculum: Description of a Successful Model

    ERIC Educational Resources Information Center

    Newell, Debra A.; Raji, Mukaila; Lieberman, Steven; Beach, Robert E.

    2004-01-01

    Most medical school curricula do not equip students with adequate attitudes, knowledge and skills to care for elderly populations. We describe an effective geriatric curricular infusion model compatible with preserving the overall curricula schema. Course and clerkship directors, staff and faculty from the Office of Educational Development, Center…

  13. Partnerships in Medical Education: An Exploration of Library Service Models for Postgraduate Medicine at Macquarie University

    ERIC Educational Resources Information Center

    Simons, Mary

    2008-01-01

    Macquarie University's new medical school, The Australian School of Advanced Medicine (ASAM), is developing a postgraduate program that incorporates a partnership with Macquarie University Library. The curriculum encompasses contemporary models of competency-based assessment, teamwork and lifelong learning that are integrated with research and…

  14. Caveat Emptor: Considerations before Buying In to the "New" Medical Model.

    ERIC Educational Resources Information Center

    Gresham, Frank M.

    2002-01-01

    In response to Forness and Kavale's (2001) argument that the field of emotional and behavioral disorders (E/BD) should adopt a "new" medical model, this commentary argues that the benefit of psychiatric diagnoses and pharmacologic treatments have not been established. It advocates a resistance-to-intervention approach to E/BD eligibility…

  15. Balancing the Imbalance: Integrating a Strength-Based Approach with a Medical Model

    ERIC Educational Resources Information Center

    Foltz, Robert

    2006-01-01

    There are major differences in perspective between the traditional medical model of treatment for troubled children and more recent strength-based approaches. This is particularly evident when widespread use of psychoactive drugs becomes a substitute for interpersonal therapeutic interventions. Drugs and relationships both impact the brain, but in…

  16. Medical Students' Emotional Development in Early Clinical Experience: A Model

    ERIC Educational Resources Information Center

    Helmich, Esther; Bolhuis, Sanneke; Laan, Roland; Dornan, Tim; Koopmans, Raymond

    2014-01-01

    Dealing with emotions is a critical feature of professional behaviour. There are no comprehensive theoretical models, however, explaining how medical students learn about emotions. We aimed to explore factors affecting their emotions and how they learn to deal with emotions in themselves and others. During a first-year nursing attachment in…

  17. Florentine anatomical models and the challenge of medical authority in late-eighteenth-century Vienna.

    PubMed

    Maerker, Anna

    2012-09-01

    This paper investigates the reception of a set of Florentine anatomical wax models on display at the medico-surgical academy Josephinum in late-eighteenth-century Vienna. Celebrated in Florence as tools of public enlightenment, in the Habsburg capital the models were criticised by physicians, who regarded the Josephinum and its surgeons as a threat to their medical authority. The controversy surrounding these models from the empire's periphery temporarily destabilised the relationship between surgeons and physicians in the Austrian capital. The debate on the utility of the Tuscan anatomical models in Vienna highlights the fact that the centre of the Habsburg empire was by no means medically homogeneous, and that the implementation of reforms could be as difficult to achieve in the capital as in the provinces. PMID:22580019

  18. Topic modeling for cluster analysis of large biological and medical datasets

    PubMed Central

    2014-01-01

    Background The big data moniker is nowhere better deserved than to describe the ever-increasing prodigiousness and complexity of biological and medical datasets. New methods are needed to generate and test hypotheses, foster biological interpretation, and build validated predictors. Although multivariate techniques such as cluster analysis may allow researchers to identify groups, or clusters, of related variables, the accuracies and effectiveness of traditional clustering methods diminish for large and hyper dimensional datasets. Topic modeling is an active research field in machine learning and has been mainly used as an analytical tool to structure large textual corpora for data mining. Its ability to reduce high dimensionality to a small number of latent variables makes it suitable as a means for clustering or overcoming clustering difficulties in large biological and medical datasets. Results In this study, three topic model-derived clustering methods, highest probable topic assignment, feature selection and feature extraction, are proposed and tested on the cluster analysis of three large datasets: Salmonella pulsed-field gel electrophoresis (PFGE) dataset, lung cancer dataset, and breast cancer dataset, which represent various types of large biological or medical datasets. All three various methods are shown to improve the efficacy/effectiveness of clustering results on the three datasets in comparison to traditional methods. A preferable cluster analysis method emerged for each of the three datasets on the basis of replicating known biological truths. Conclusion Topic modeling could be advantageously applied to the large datasets of biological or medical research. The three proposed topic model-derived clustering methods, highest probable topic assignment, feature selection and feature extraction, yield clustering improvements for the three different data types. Clusters more efficaciously represent truthful groupings and subgroupings in the data than

  19. [The professional differentiation in medical practice. A theoretical model of the process of changing].

    PubMed

    Zerón-Gutiérrez, Lydia Estela; Lifshitz, Alberto; Ramiro H, Manuel; Abreu-Hernández, Luis Felipe; Reyes-Lagunes, Isabel

    2012-01-01

    The structure of the change process on medical professionalization has not being studied enough. The physicians are made aware of the necessity of changing their medical practice in ways that also affect their personal life. A change involves the need to plan, evaluate possibilities and resources with efficacy and outline competencies. The aim is to contribute in the design of educational strategies that promote professional change and an understanding of change, as an evolution; we describe a theoretical-schematic model based on five consecutive ordained scopes: background, intentions, planning and making decisions, carrying out decisions and achieving the goal. PMID:23331751

  20. Physician's information customizer (PIC): using a shareable user model to filter the medical literature.

    PubMed

    Pratt, W; Sim, I

    1995-01-01

    The practice of medicine is information-intensive. From reviewing the literature to formulating therapeutic plans, each physician handles information differently. Yet rarely does a representation of the user's information needs and preferences--a user model--get incorporated into information management tools, even though we might reasonably expect better acceptance and effectiveness if the tools' presentation and processing were customized to the user. We developed the Physician's Information Customizer (PIC), which generates a shareable user model that can be used in any medical information-management application. PIC elicits the stable, long-term attributes of a physician through simple questions about her specialty, research focus, areas of interest, patient characteristics (e.g., ages), and practice locale. To show the utility of this user model in customizing a medical informatics application, PIC custom-filters and ranks articles from Medline, using the user model to determine what would be most interesting to the user. Preliminary evaluation on all 99 unselected articles from a recent issue of six prominent medical journals shows that PIC ranks 66% of the articles as the user would. This demonstrates the feasibility of using easily acquired physician attributes to develop a user model that can successfully filter articles of interest from a large undifferentiated collection. Further testing and development is required to optimize the custom filter and to determine which characteristics should be included in the shareable user model and which should be obtained by individual applications. PMID:8591472

  1. Limitations of Western Medicine and Models of Integration Between Medical Systems.

    PubMed

    Attena, Francesco

    2016-05-01

    This article analyzes two major limitations of Western medicine: maturity and incompleteness. From this viewpoint, Western medicine is considered an incomplete system for the explanation of living matter. Therefore, through appropriate integration with other medical systems, in particular nonconventional approaches, its knowledge base and interpretations may be widened. This article presents possible models of integration of Western medicine with homeopathy, the latter being viewed as representative of all complementary and alternative medicine. To compare the two, a medical system was classified into three levels through which it is possible to distinguish between different medical systems: epistemological (first level), theoretical (second level), and operational (third level). These levels are based on the characterization of any medical system according to, respectively, a reference paradigm, a theory on the functioning of living matter, and clinical practice. The three levels are consistent and closely consequential in the sense that from epistemology derives theory, and from theory derives clinical practice. Within operational integration, four models were identified: contemporary, alternative, sequential, and opportunistic. Theoretical integration involves an explanation of living systems covering simultaneously the molecular and physical mechanisms of functioning living matter. Epistemological integration provides a more thorough and comprehensive explanation of the epistemic concepts of indeterminism, holism, and vitalism to complement the reductionist approach of Western medicine; concepts much discussed by Western medicine while lacking the epistemologic basis for their emplacement. Epistemologic integration could be reached with or without a true paradigm shift and, in the latter, through a model of fusion or subsumption. PMID:27070976

  2. Systems modeling of space medical support architecture: topological mapping of high level characteristics and constraints.

    PubMed

    Musson, David M; Doyle, Thomas E; Saary, Joan

    2012-01-01

    The challenges associated with providing medical support to astronauts on long duration lunar or planetary missions are significant. Experience to date in space has included short duration missions to the lunar surface and both short and long duration stays on board spacecraft and space stations in low Earth orbit. Live actor, terrestrial analogue setting simulation provides a means of studying multiple aspects of the medical challenges of exploration class space missions, though few if any published models exist upon which to construct systems-simulation test beds. Current proposed and projected moon mission scenarios were analyzed from a systems perspective to construct such a model. A resulting topological mapping of high-level architecture for a reference lunar mission with presumed EVA excursion and international mission partners is presented. High-level descriptions of crew operational autonomy, medical support related to crew-member status, and communication characteristics within and between multiple teams are presented. It is hoped this modeling will help guide future efforts to simulate medical support operations for research purposes, such as in the use of live actor simulations in terrestrial analogue environments. PMID:23367318

  3. Mass medication modeling in response to public health emergencies: outcomes of a drive-thru exercise.

    PubMed

    Zerwekh, Tyler; McKnight, Jason; Hupert, Nathaniel; Wattson, Daniel; Hendrickson, Lisa; Lane, David

    2007-01-01

    This article presents the outcomes of a full-scale training exercise utilizing a drive-thru clinic model for dispensing of Strategic National Stockpile medication. The Hawaii Department of Health developed a clinic design for vehicles based on previous exercises and research on sample throughput rates. The streamlined model selected includes a triage area near the entrance and consecutive stations for the public to register, have an evaluation for drug contradictions, and receive the medication. During the 2-hour exercise held in April 2005, a total of 622 patients were processed in their vehicles for an overall rate of 5.2 persons per minute. Although patient services were reduced in comparison to current walk-in clinic models, the public was able to receive prophylactic medication in a timely manner with a high rate of accuracy and minimal human-to-human contact. These results demonstrate that local health departments, particularly in rural areas, can provide essential medications, vaccinations, or rations through a drive-thru clinic, thus limiting morbidity and mortality during a public health emergency. PMID:17149094

  4. Creation of Anatomically Accurate Computer-Aided Design (CAD) Solid Models from Medical Images

    NASA Technical Reports Server (NTRS)

    Stewart, John E.; Graham, R. Scott; Samareh, Jamshid A.; Oberlander, Eric J.; Broaddus, William C.

    1999-01-01

    Most surgical instrumentation and implants used in the world today are designed with sophisticated Computer-Aided Design (CAD)/Computer-Aided Manufacturing (CAM) software. This software automates the mechanical development of a product from its conceptual design through manufacturing. CAD software also provides a means of manipulating solid models prior to Finite Element Modeling (FEM). Few surgical products are designed in conjunction with accurate CAD models of human anatomy because of the difficulty with which these models are created. We have developed a novel technique that creates anatomically accurate, patient specific CAD solids from medical images in a matter of minutes.

  5. Medical Image Segmentation Based on a Hybrid Region-Based Active Contour Model

    PubMed Central

    Liu, Tingting; Xu, Haiyong; Liu, Zhen; Zhao, Yiming; Tian, Wenzhe

    2014-01-01

    A novel hybrid region-based active contour model is presented to segment medical images with intensity inhomogeneity. The energy functional for the proposed model consists of three weighted terms: global term, local term, and regularization term. The total energy is incorporated into a level set formulation with a level set regularization term, from which a curve evolution equation is derived for energy minimization. Experiments on some synthetic and real images demonstrate that our model is more efficient compared with the localizing region-based active contours (LRBAC) method, proposed by Lankton, and more robust compared with the Chan-Vese (C-V) active contour model. PMID:25028593

  6. Reflections on the medical model and the objectives of health education.

    PubMed

    Van Parijs, L

    1980-01-01

    A recent article in the IJHE deals with the linkage of health education to a medical model philosophy and discusses the origins and consequences of medical dominance on health education practice (Vuori, 1980). This paper questions some of the observations and conclusions on which the medical dominance premise is based and argues that historical developments and the current state of affairs of health education do not fully support a medical dominance thesis. For example, there is a historical omission concerning the growth and influence of social and behavioural sciences on health education theory and practice. Also, current health education systems and services in European countries do not unequivocally support the medical influence premise, nor do training programmes and research. The paper further re-examines some statements about the possible consequences of medical dominance on current health education practice, especially as regards the usefulness of single-theme campaigns, the use of health services and the dissemination of medical knowledge. Opinions about the use of individual versus social means of action are discussed, as well as the need for health education to invest more energy in creating favourable attitudes towards the use of legislative and administrative measures. Finally, the discussion centres on the proposition that health education should be more concerned with the internalization of health values. It is argued that it would be useful to re-examine the conceptual base of health education in developmental terms and proposed that we reflect on the organization of health education activities and service around five sectors of socialization. These are interdependent, yet play a specific role in health education throughout the various stages of life. PMID:7467862

  7. An investigative model evaluating how consumers process pictorial information on nonprescription medication labels.

    PubMed

    Sansgiry, S S; Cady, P S

    1997-01-01

    Currently, marketed over-the-counter (OTC) medication labels were simulated and tested in a controlled environment to understand consumer evaluation of OTC label information. Two factors, consumers' age (younger and older adults) and label designs (picture-only, verbal-only, congruent picture-verbal, and noncongruent picture-verbal) were controlled and tested to evaluate consumer information processing. The effects exerted by the independent variables, namely, comprehension of label information (understanding) and product evaluations (satisfaction, certainty, and perceived confusion) were evaluated on the dependent variable purchase intention. Intention measured as purchase recommendation was significantly related to product evaluations and affected by the factor label design. Participants' level of perceived confusion was more important than actual understanding of information on OTC medication labels. A Label Evaluation Process Model was developed which could be used for future testing of OTC medication labels. PMID:10168485

  8. Unforeseen ethical/legal complications with screening tests in the capitation model of medical aid schemes.

    PubMed

    Jansen, Rita-Marie; Gouws, Chris; Verschoor, Teuns

    2012-10-01

    In the South African health care system patients/consumers are divided into those who can afford private care and those who rely on state medical assistance. The system is under pressure to fund delivery of medical care to its beneficiaries. We consider the effects of different funding models on medicolegal liability of health professionals serving the private sector. Medical reasons should determine the service rendered. However, financial implications of services rendered and defensive practice of medicine also contribute to treatment received by a patient and its remuneration. Practitioners who commit to delivering a predetermined set of services within a particular time for a predetermined 'lump sum' are only paid for the service specifically requested. Should disease be found other than those contracted for, we argue that inaction with regard to that disease would be deemed to be negligent or unethical according to legal and ethical considerations. PMID:23034204

  9. A 3-dimensional digital atlas of the ascending sensory and the descending motor systems in the pigeon brain.

    PubMed

    Güntürkün, Onur; Verhoye, Marleen; De Groof, Geert; Van der Linden, Annemie

    2013-01-01

    Pigeons are classic animal models for learning, memory, and cognition. The majority of the current understanding about avian neurobiology outside of the domain of the song system has been established using pigeons. Since MRI represents an increasingly relevant tool for comparative neuroscience, a 3-dimensional MRI-based atlas of the pigeon brain becomes essential. Using multiple imaging protocols, we delineated diverse ascending sensory and descending motor systems as well as the hippocampal formation. This pigeon brain atlas can easily be used to determine the stereotactic location of identified neural structures at any angle of the head. In addition, the atlas is useful to find the optimal angle of sectioning for slice experiments, stereotactic injections and electrophysiological recordings. This pigeon brain atlas is freely available for the scientific community. PMID:22367250

  10. Towards non-AdS holography in 3-dimensional higher spin gravity

    NASA Astrophysics Data System (ADS)

    Gary, Michael; Grumiller, Daniel; Rashkov, Radoslav

    2012-03-01

    We take the first steps towards non-AdS holography in higher spin gravity. Namely, we propose a variational principle for generic 3-dimensional higher spin gravity that accommodates asymptotic backgrounds beyond AdS, like asymptotically Schrödinger, Lifshitz or warped AdS spacetimes. As examples we study in some detail the four sl(2) embeddings of spin-4 gravity and provide associated geometries, including an asymptotic Lifshitz black hole.

  11. Energy Sources of the Dominant Frequency Dependent 3-dimensional Atmospheric Modes

    NASA Technical Reports Server (NTRS)

    Schubert, S.

    1985-01-01

    The energy sources and sinks associated with the zonally asymmetric winter mean flow are investigated as part of an on-going study of atmospheric variability. Distinctly different horizontal structures for the long, intermediate and short time scale atmospheric variations were noted. In previous observations, the 3-dimensional structure of the fluctuations is investigated and the relative roles of barotropic and baroclinic terms are assessed.

  12. Presentation and explanation of medical decision models using the World Wide Web.

    PubMed Central

    Sanders, G. D.; Dembitzer, A. D.; Heidenreich, P. A.; McDonald, K. M.; Owens, D. K.

    1996-01-01

    We demonstrated the use of the World Wide Web for the presentation and explanation of a medical decision model. We put on the web a treatment model developed as part of the Cardiac Arrhythmia and Risk of Death Patient Outcomes Research Team (CARD PORT). To demonstrate the advantages of our web-based presentation, we critiqued both the conventional paper-based and the web-based formats of this decision-model presentation with reference to an accepted published guide to understanding clinical decision models. A web-based presentation provides a useful supplement to paper-based publications by allowing authors to present their model in greater detail, to link model inputs to the primary evidence, and to disseminate the model to peer investigators for critique and collaborative modeling. PMID:8947628

  13. A novel level set model with automated initialization and controlling parameters for medical image segmentation.

    PubMed

    Liu, Qingyi; Jiang, Mingyan; Bai, Peirui; Yang, Guang

    2016-03-01

    In this paper, a level set model without the need of generating initial contour and setting controlling parameters manually is proposed for medical image segmentation. The contribution of this paper is mainly manifested in three points. First, we propose a novel adaptive mean shift clustering method based on global image information to guide the evolution of level set. By simple threshold processing, the results of mean shift clustering can automatically and speedily generate an initial contour of level set evolution. Second, we devise several new functions to estimate the controlling parameters of the level set evolution based on the clustering results and image characteristics. Third, the reaction diffusion method is adopted to supersede the distance regularization term of RSF-level set model, which can improve the accuracy and speed of segmentation effectively with less manual intervention. Experimental results demonstrate the performance and efficiency of the proposed model for medical image segmentation. PMID:26748038

  14. Development of automatic body condition scoring using a low-cost 3-dimensional Kinect camera.

    PubMed

    Spoliansky, Roii; Edan, Yael; Parmet, Yisrael; Halachmi, Ilan

    2016-09-01

    Body condition scoring (BCS) is a farm-management tool for estimating dairy cows' energy reserves. Today, BCS is performed manually by experts. This paper presents a 3-dimensional algorithm that provides a topographical understanding of the cow's body to estimate BCS. An automatic BCS system consisting of a Kinect camera (Microsoft Corp., Redmond, WA) triggered by a passive infrared motion detector was designed and implemented. Image processing and regression algorithms were developed and included the following steps: (1) image restoration, the removal of noise; (2) object recognition and separation, identification and separation of the cows; (3) movie and image selection, selection of movies and frames that include the relevant data; (4) image rotation, alignment of the cow parallel to the x-axis; and (5) image cropping and normalization, removal of irrelevant data, setting the image size to 150×200 pixels, and normalizing image values. All steps were performed automatically, including image selection and classification. Fourteen individual features per cow, derived from the cows' topography, were automatically extracted from the movies and from the farm's herd-management records. These features appear to be measurable in a commercial farm. Manual BCS was performed by a trained expert and compared with the output of the training set. A regression model was developed, correlating the features with the manual BCS references. Data were acquired for 4 d, resulting in a database of 422 movies of 101 cows. Movies containing cows' back ends were automatically selected (389 movies). The data were divided into a training set of 81 cows and a test set of 20 cows; both sets included the identical full range of BCS classes. Accuracy tests gave a mean absolute error of 0.26, median absolute error of 0.19, and coefficient of determination of 0.75, with 100% correct classification within 1 step and 91% correct classification within a half step for BCS classes. Results indicated

  15. Acromiohumeral Distance and 3-Dimensional Scapular Position Change After Overhead Muscle Fatigue

    PubMed Central

    Maenhout, Annelies; Dhooge, Famke; Van Herzeele, Maarten; Palmans, Tanneke; Cools, Ann

    2015-01-01

    Context: Muscle fatigue due to repetitive and prolonged overhead sports activity is considered an important factor contributing to impingement-related rotator cuff pathologic conditions in overhead athletes. The evidence on scapular and glenohumeral kinematic changes after fatigue is contradicting and prohibits conclusions about how shoulder muscle fatigue affects acromiohumeral distance. Objective: To investigate the effect of a fatigue protocol resembling overhead sports activity on acromiohumeral distance and 3-dimensional scapular position in overhead athletes. Design: Cross-sectional study. Setting: Institutional laboratory. Patients or Other Participants: A total of 29 healthy recreational overhead athletes (14 men, 15 women; age = 22.23 ± 2.82 years, height = 178.3 ± 7.8 cm, mass = 71.6 ± 9.5 kg). Intervention(s) The athletes were tested before and after a shoulder muscle-fatiguing protocol. Main Outcome Measure(s) Acromiohumeral distance was measured using ultrasound, and scapular position was determined with an electromagnetic motion-tracking system. Both measurements were performed at 3 elevation positions (0°, 45°, and 60° of abduction). We used a 3-factor mixed model for data analysis. Results: After fatigue, the acromiohumeral distance increased when the upper extremity was actively positioned at 45° (Δ = 0.78 ± 0.24 mm, P = .002) or 60° (Δ = 0.58 ± 0.23 mm, P = .02) of abduction. Scapular position changed after fatigue to a more externally rotated position at 45° (Δ = 4.97° ± 1.13°, P < .001) and 60° (Δ = 4.61° ± 1.90°, P = .001) of abduction, a more upwardly rotated position at 45° (Δ = 6.10° ± 1.30°, P < .001) and 60° (Δ = 7.20° ± 1.65°, P < .001) of abduction, and a more posteriorly tilted position at 0°, 45°, and 60° of abduction (Δ = 1.98° ± 0.41°, P < .001). Conclusions: After a fatiguing protocol, we found changes in acromiohumeral distance and scapular position that corresponded with an impingement

  16. Three-Dimensional Printing and Medical Imaging: A Review of the Methods and Applications.

    PubMed

    Marro, Alessandro; Bandukwala, Taha; Mak, Walter

    2016-01-01

    The purpose of this article is to review recent innovations on the process and application of 3-dimensional (3D) printed objects from medical imaging data. Data for 3D printed medical models can be obtained from computed tomography, magnetic resonance imaging, and ultrasound using the Data Imaging and Communications in Medicine (DICOM) software. The data images are processed using segmentation and mesh generation tools and converted to a standard tessellation language (STL) file for printing. 3D printing technologies include stereolithography, selective laser sintering, inkjet, and fused-deposition modeling . 3D printed models have been used for preoperative planning of complex surgeries, the creation of custom prosthesis, and in the education and training of physicians. The application of medical imaging and 3D printers has been successful in providing solutions to many complex medical problems. As technology advances, its applications continue to grow in the future. PMID:26298798

  17. Single-Molecule Imaging of DNA Pairing by RecA Reveals a 3-Dimensional Homology Search

    PubMed Central

    Forget, Anthony L.; Kowalczykowski, Stephen C.

    2011-01-01

    DNA breaks can be repaired with high-fidelity by homologous recombination. A ubiquitous protein that is essential for this DNA template-directed repair is RecA1. After resection of broken DNA to produce single-stranded DNA (ssDNA), RecA assembles on this ssDNA into a filament with the unique capacity to search and find DNA sequences in double-stranded DNA (dsDNA) that are homologous to the ssDNA. This homology search is vital to recombinational DNA repair, and results in homologous pairing and exchange of DNA strands. Homologous pairing involves DNA sequence-specific target location by the RecA-ssDNA complex. Despite decades of study, the mechanism of this enigmatic search process remains unknown. RecA is a DNA-dependent ATPase, but ATP hydrolysis is not required for DNA pairing and strand exchange2,3, eliminating active search processes. Using dual optical trapping to manipulate DNA, and single-molecule fluorescence microscopy to image DNA pairing, we demonstrate that both the three-dimensional conformational state of the dsDNA target and the length of the homologous RecA-ssDNA filament play important roles in the homology search. We discovered that as the end-to-end distance of the target dsDNA molecule is increased, constraining its available 3-dimensional conformations, the rate of homologous pairing decreases. Conversely, when the length of the ssDNA in the nucleoprotein filament is increased, homology is found faster. We propose a model for the DNA homology search process termed “intersegmental contact sampling”, wherein the intrinsic multivalent nature of the RecA nucleoprotein filament is employed to search DNA sequence space within 3-dimensional domains of DNA, exploiting multiple weak contacts to rapidly search for homology. Our findings highlight the importance of the 3-dimensional conformational dynamics of DNA, reveal a previously unknown facet of the homology search, and provide insight into the mechanism of DNA target location by this member of a

  18. Using a facilitation model to achieve patient-centered medical home recognition.

    PubMed

    Lane, Sandi J; Watkins, R W Chip

    2015-01-01

    This article describes how a facilitation model that included a partnership between a Community Care of North Carolina network and undergraduates at a regional university supported rural primary care practices in transforming their practices to become National Committee for Quality Assurance-recognized patient-centered medical homes. Health care management and preprofessional undergraduate students worked with 14 rural primary care practices to redesign practice processes and complete the patient-centered medical home application. Twelve of the practices participated in the evaluation of the student contribution. A semistructured interview guide containing questions about practice characteristics, student competencies, and the value of the student's contribution to their practice's achievement of patient-centered medical home recognition was used to interview practice managers or their designee. Analysis included item-descriptive statistics and qualitative analysis of narrative content. All 12 participating practices achieved 2011 National Committee for Quality Assurance patient-centered medical home recognition, with 4 practices achieving level 3, 5 practices achieving level 2, and 3 practices achieving level 1. The facilitation model using partnerships between health care agencies and universities might be an option for enhancing a practice's internal capacity for successful transformation and should be explored further. PMID:25909396

  19. A new model for providing prehospital medical care in large stadiums.

    PubMed

    Spaite, D W; Criss, E A; Valenzuela, T D; Meislin, H W; Smith, R; Nelson, A

    1988-08-01

    To determine proper priorities for the provision of health care in large stadiums, we studied the medical incident patterns occurring in a major college facility and combined this with previously reported information from four other large stadiums. Medical incidents were an uncommon occurrence (1.20 to 5.23 per 10,000 people) with true medical emergencies being even more unusual (0.09 to 0.31 per 10,000 people). Cardiac arrest was rare (0.01 to 0.04 events per 10,000 people). However, the rates of successful resuscitation in three studies were 85% or higher. The previous studies were descriptive in nature and failed to provide specific recommendations for medical aid system configuration or response times. A model is proposed to provide rapid response of advanced life support care to victims of cardiac arrest. We believe that the use of this model in large stadiums throughout the United States could save as many as 100 lives during each football season. PMID:3394987

  20. Model of medical supply and astronaut health for long-duration human space flight

    NASA Astrophysics Data System (ADS)

    Assad, Albert; de Weck, Olivier L.

    2015-01-01

    Planning a safe and productive human space exploration mission involves a dual approach addressing both the health of the vehicle and the crew. The goal of this study was to develop a quantitative model of astronaut health during long-duration space flight and a medical supply demand model in support of such missions. The model provides two outputs, Alphah and Mass of Medical Consumables (MMC), for each set of input parameters. Alphah is an estimate of total crew health and is displayed as a percentage. MMC is a measure of medical consumables expended during the mission and is displayed in units of kilograms. We have demonstrated that Alphah is a function of three scaling parameters, the type of mission, duration of mission, and gender mix of the crew. The type of mission and gender of crew are linked to radiation fatality data published by NASA. Mission duration is incorporated into the model with predicted incidence of illness and injury data published on US Navy submarine crews. MMC increases non-linearly with the number of crew, the duration of the mission and the distance of the mission away from Earth. This article describes the relationships between these parameters and discusses implications for future crewed space missions.

  1. A Social Problem-Solving Model of Adherence to HIV Medications

    PubMed Central

    Johnson, Mallory O.; Elliott, Timothy R.; Neilands, Torsten B.; Morin, Stephen F.; Chesney, Margaret A.

    2008-01-01

    HIV medication adherence remains a challenge and limits the degree to which treatment benefit can be maximized. The purpose of this paper is to test an explanatory model of HIV medication adherence using a social problem-solving (SPS) framework. Associations of SPS with adherence are hypothesized to be direct and/or indirect via psychological health. HIV+ adults were interviewed using validated measures of SPS, psychological health, and antiretroviral (ART) medication adherence. Structural equation modeling (SEM) techniques were employed to test hypothesized relationships and to evaluate overall fit of the model to the data. SEM supported an indirect association (but not direct) of SPS on adherence via psychological health among the 545 HIV+ adults included in the analyses. Overall, the findings resulted in a model of adherence that offered very good fit to the data and correctly classified 97% of the cases as adherent versus non-adherent. Results support the use of SPS as a conceptual framework for understanding adherence to ART. Findings offer rationale and direction for SPS interventions to enhance adherence by improving psychological health. Such approaches, if effective, have the potential to positively impact psychological well being and adherence, thereby maximizing clinical benefit from treatment, which is linked to lower mortality from AIDS. PMID:16719607

  2. Decision-analytic modeling to evaluate benefits and harms of medical tests: uses and limitations.

    PubMed

    Trikalinos, Thomas A; Siebert, Uwe; Lau, Joseph

    2009-01-01

    The clinical utility of medical tests is measured by whether the information they provide affects patient-relevant outcomes. To a large extent, effects of medical tests are indirect in nature. In principle, a test result affects patient outcomes mainly by influencing treatment choices. This indirectness in the link between testing and its downstream effects poses practical challenges to comparing alternate test-and-treat strategies in clinical trials. Keeping in mind the broader audience of researchers who perform comparative effectiveness reviews and technology assessments, the authors summarize the rationale for and pitfalls of decision modeling in the comparative evaluation of medical tests by virtue of specific examples. Modeling facilitates the interpretation of test performance measures by connecting the link between testing and patient outcomes, accounting for uncertainties and explicating assumptions, and allowing the systematic study of tradeoffs and uncertainty. The authors discuss challenges encountered when modeling test-and-treat strategies, including but not limited to scarcity of data on important parameters, transferring estimates of test performance across studies, choosing modeling outcomes, and obtaining summary estimates for test performance data. PMID:19734441

  3. [The fate of a model of Pathological Anatomy Institute of Medical Faculty in Prague].

    PubMed

    Hlavácková, Ludmila

    2012-01-01

    In the former Pathological Anatomy Institute of the German Medical Faculty in Prague (U Nemocnice 4) a rare model of this building, made in 1861 for the World Exhibition in London has been preserved. The model was finally not sent to the London exhibition. Documents illuminating the fate of this valuable monument found in the National Archive. Thanks to the department head emeritus PhDr. A. Malecková and her successor Ph.Dr. H. Skálová this model was professionally restored by Mr. Antonin Hruska in 2010. PMID:22679689

  4. How students experience and navigate transitions in undergraduate medical education: an application of Bourdieu's theoretical model.

    PubMed

    Balmer, Dorene F; Richards, Boyd F; Varpio, Lara

    2015-10-01

    Using Bourdieu's theoretical model as a lens for analysis, we sought to understand how students experience the undergraduate medical education (UME) milieu, focusing on how they navigate transitions from the preclinical phase, to the major clinical year (MCY), and to the preparation for residency phase. Twenty-two medical students participated in this longitudinal case study. Students had similar preclinical and post-MCY experiences but different MCY experiences (rotational vs. longitudinal tracks). We interviewed students every 6 months in the preclinical phase, mid-way through MCY, and 7-8 months before graduation (101 total interviews). We inductively created codes, iteratively revised codes to best-fit the data, and thematically clustered codes into Bourdieu-informed categories: field (social structures), capital (resources) and habitus (dispositions). We found that students acclimated to shifts in the UME field as they moved through medical school: from medical school itself to the health system and back. To successfully navigate transitions, students learned to secure capital as medical knowledge and social connections in the preclinical and preparation for residency phases, and as reputable patient care and being noticed in the clinical phase. To obtain capital, and be well-positioned for the next phase of training, students consistently relied on dispositions of initiative and flexibility. In summary, students experience the complex context of medical school through a series of transitions. Efforts to improve UME would be well-served by greater awareness of the social structures (field) that students encounter, the resources to which they afford value (capital), and the dispositions which aid acquisition of these resources (habitus). PMID:25633168

  5. Is culture important in the choice of role models? Experiences from a culturally diverse medical school.

    PubMed

    McLean, Michelle

    2004-03-01

    In a multicultural student population at a South African medical school, for over one-third of students (Years 1-5) undertaking a traditional curriculum, culture was an important consideration in their choice of a role model. This was particularly so for senior students, perhaps reflecting their relatively recent exposure to patients and their forthcoming internship. Some student comments might, however, be interpreted as reflecting a rigid perception of culture that could translate into a possible lack of respect for other cultures. It is therefore imperative that each institution provide appropriate early and continuous mainstream diversity training, as well as identify role models to match the student profile. With the increasing diversity of students globally, this issue of culture should assume even greater importance in medical education than it is currently afforded. PMID:15203523

  6. Pathology service line: a model for accountable care organizations at an academic medical center.

    PubMed

    Sussman, Ira; Prystowsky, Michael B

    2012-05-01

    Accountable care is designed to manage the health of patients using a capitated cost model rather than fee for service. Pay for performance is an attempt to use quality and not service reduction as the way to decrease costs. Pathologists will have to demonstrate value to the system. This value will include (1) working with clinical colleagues to optimize testing protocols, (2) reducing unnecessary testing in both clinical and anatomic pathology, (3) guiding treatment by helping to personalize therapy, (4) designing laboratory information technology solutions that will promote and facilitate accurate, complete data mining, and (5) administering efficient cost-effective laboratories. The pathology service line was established to improve the efficiency of delivering pathology services and to provide more effective support of medical center programs. We have used this model effectively at the Montefiore Medical Center for the past 14 years. PMID:22333926

  7. Jackson Community Medical Record: a model for provider collaboration in a RHIO.

    PubMed

    Hayward, Mary K; Warren, Richard D; Sykes, Jonathan

    2007-01-01

    Foote Health System serves more than 247,000 individuals throughout six Michigan counties. In January 2005, FHS and Jackson Physicians Alliance, a 160-member physician contracting group, joined together to champion a community electronic health record by forming Jackson Community Medical Record LLC. JCMR selected and implemented of a fully integrated HIPAA-compliant EHR hosted on an application service provider. The shared database enables providers to leverage the work of each other. The community is already experiencing the benefits of the HER, including increased accuracy of medications, patient satisfaction, efficiency and reimbursement. The JCMR business model provides low entry costs and economies of scale. Software licenses and services are negotiated and held by JCMR. The interfaces between hospital systems and providers are maximized. JCMR is successfully bringing isolated islands of patient data together and serves a model for other communities. PMID:19195291

  8. Postdependent state in rats as a model for medication development in alcoholism.

    PubMed

    Meinhardt, Marcus W; Sommer, Wolfgang H

    2015-01-01

    Rational development of novel therapeutic strategies for alcoholism requires understanding of its underlying neurobiology and pathophysiology. Obtaining this knowledge largely relies on animal studies. Thus, choosing the appropriate animal model is one of the most critical steps in pre-clinical medication development. Among the range of animal models that have been used to investigate excessive alcohol consumption in rodents, the postdependent model stands out. It was specifically developed to test the role of negative affect as a key driving force in a perpetuating addiction cycle for alcoholism. Here, we will describe our approach to make rats dependent via chronic intermittent exposure to alcohol, discuss the validity of this model, and compare it with other commonly used animal models of alcoholism. We will summarize evidence that postdependent rats fulfill several criteria of a 'Diagnostic and Statistical Manual of Mental Disorders IV/V-like' diagnostic system. Importantly, these animals show long-lasting excessive consumption of and increased motivation for alcohol, and evidence for loss of control over alcohol intake. Our conclusion that postdependent rats are an excellent model for medication development for alcoholism is underscored by a summary of more than two dozen pharmacological tests aimed at reversing these abnormal alcohol responses. We will end with open questions on the use of this model. In the tradition of the Sanchis-Segura and Spanagel review, we provide comic strips that illustrate the postdependent procedure and relevant phenotypes in this review. PMID:25403107

  9. Accomplishments in genome-scale in silico modeling for industrial and medical biotechnology

    PubMed Central

    Milne, Caroline B.; Kim, Pan-Jun; Eddy, James A.; Price, Nathan D.

    2011-01-01

    Driven by advancements in high-throughput biological technologies and the growing number of sequenced genomes, the construction of in silico models at the genome scale has provided powerful tools to investigate a vast array of biological systems and applications. Here, we review comprehensively the uses of such models in industrial and medical biotechnology, including biofuel generation, food production, and drug development. While the use of in silico models is still in its early stages for delivering to industry, significant initial successes have been achieved. For the cases presented here, genome-scale models predict engineering strategies to enhance properties of interest in an organism or to inhibit harmful mechanisms of pathogens or in disease. Going forward, genome-scale in silico models promise to extend their application and analysis scope to become a transformative tool in biotechnology. As such, genome-scale models can provide a basis for rational genome-scale engineering and synthetic biology. PMID:19946878

  10. A Comparison of Expedition Medical Condition List Treatment Directives with Integrated Medical Model Simulation Data Presentation and Briefing Report

    NASA Technical Reports Server (NTRS)

    Lewis, Robert

    2013-01-01

    This aerospace medicine clerkship project is under the direction of Dr. Sharmila Watkins and is in cooperation with Dr. Eric Kerstman and Dr. Ronak Shah. The questions of the research project are: 1. What are the main drivers of evacuation and loss of crew life (LOCL) on three Design Reference Missions (DRMs): Near Earth Asteroid (NEA), Lunar Sortie and Lunar Outpost using an inexhaustible International Space Station medical kit 2. What are the treatment designations for these driving medical conditions as listed in Expedition Medical Condition List (EMCL) 3. Do the drivers make sense in the context of the given Design Reference Mission (DRM) 4. Do any EMCL treatment designations need re-assessing.

  11. Use of three-dimensional medical modeling methods for precise planning of orthognathic surgery.

    PubMed

    Mavili, Mehmet Emin; Canter, Halil Ibrahim; Saglam-Aydinatay, Banu; Kamaci, Soner; Kocadereli, Ilken

    2007-07-01

    Stereolithographic (medical rapid prototyping) biomodeling allows three-dimensional computed tomography to be used to generate solid plastic replicas of anatomic structures. Reports in the literature suggest that such biomodels may have a use in maxillofacial surgery, craniofacial surgery, orthopedics, neurosurgery, otology, vascular, and nasal research. A prospective trial to assess the usefulness of biomodeling in orthognathic surgery has been performed. In 12 patients with mandibular prognathism and/or maxillary retrusion, in addition to routine preoperative cephalometric analysis, preoperative high-resolution (cutting slice thickness of 1 mm) three-dimensional computed tomography scan of the patients was obtained. Raw data obtained from computed tomography scanning was processed with a Mimics 9.22 Software (Materialise's Interactive Medical Image Control System, Belgium). Fabrication of three-dimensional medical models was obtained through a process called powder depositional modeling by use of a Spectrum Z 510 3D Color Printer (Z Corporation, Burlington, MA). Alveolar arches of the maxilla and mandibula of the models were replaced with orthodontic dental cast models. Temporomandibular joints of the models were fixed with Kirschner wire. Maxillary and mandibular bony segments were mobilized according to preoperative orthodontic planning done by analysis of cephalometric plain radiographs. The relation between proximal and distal mandibular segments after bilateral sagittal split osteotomies were evaluated on models preoperatively. The same surgeon had a role in both model cutting preoperatively and as an instructor preoperatively. The same bony relation was observed both in preoperative modelsand in the perioperative surgical field in all patients. Condylar malpositioning was not observed in any of the patients. Studying preoperative planned movements of osteotomized bone segments and observing relations of osteotomized segments of mandibula and maxilla in

  12. Hospital adoption of medical technology: an empirical test of alternative models.

    PubMed Central

    Teplensky, J. D.; Pauly, M. V.; Kimberly, J. R.; Hillman, A. L.; Schwartz, J. S.

    1995-01-01

    OBJECTIVE. This study examines hospital motivations to acquire new medical technology, an issue of considerable policy relevance: in this case, whether, when, and why hospitals acquire a new capital-intensive medical technology, magnetic resonance imaging equipment (MRI). STUDY DESIGN. We review three common explanations for medical technology adoption: profit maximization, technological preeminence, and clinical excellence, and incorporate them into a composite model, controlling for regulatory differences, market structures, and organizational characteristics. All four models are then tested using Cox regressions. DATA SOURCES. The study is based on an initial sample of 637 hospitals in the continental United States that owned or leased an MRI unit as of 31 December 1988, plus nonadopters. Due to missing data the final sample consisted of 507 hospitals. The data, drawn from two telephone surveys, are supplemented by the AHA Survey, census data, and industry and academic sources. PRINCIPAL FINDING. Statistically, the three individual models account for roughly comparable amounts of variance in past adoption behavior. On the basis of explanatory power and parsimony, however, the technology model is "best." Although the composite model is statistically better than any of the individual models, it does not add much more explanatory power adjusting for the number of variables added. CONCLUSIONS. The composite model identified the importance a hospital attached to being a technological leader, its clinical requirements, and the change in revenues it associated with the adoption of MRI as the major determinants of adoption behavior. We conclude that a hospital's adoption behavior is strongly linked to its strategic orientation. PMID:7649751

  13. Using GOMS models and hypertext to create representations of medical procedures for online display

    NASA Technical Reports Server (NTRS)

    Gugerty, Leo; Halgren, Shannon; Gosbee, John; Rudisill, Marianne

    1991-01-01

    This study investigated two methods to improve organization and presentation of computer-based medical procedures. A literature review suggested that the GOMS (goals, operators, methods, and selecton rules) model can assist in rigorous task analysis, which can then help generate initial design ideas for the human-computer interface. GOMS model are hierarchical in nature, so this study also investigated the effect of hierarchical, hypertext interfaces. We used a 2 x 2 between subjects design, including the following independent variables: procedure organization - GOMS model based vs. medical-textbook based; navigation type - hierarchical vs. linear (booklike). After naive subjects studies the online procedures, measures were taken of their memory for the content and the organization of the procedures. This design was repeated for two medical procedures. For one procedure, subjects who studied GOMS-based and hierarchical procedures remembered more about the procedures than other subjects. The results for the other procedure were less clear. However, data for both procedures showed a 'GOMSification effect'. That is, when asked to do a free recall of a procedure, subjects who had studies a textbook procedure often recalled key information in a location inconsistent with the procedure they actually studied, but consistent with the GOMS-based procedure.

  14. Useful measures and models for analytical quality management in medical laboratories.

    PubMed

    Westgard, James O

    2016-02-01

    The 2014 Milan Conference "Defining analytical performance goals 15 years after the Stockholm Conference" initiated a new discussion of issues concerning goals for precision, trueness or bias, total analytical error (TAE), and measurement uncertainty (MU). Goal-setting models are critical for analytical quality management, along with error models, quality-assessment models, quality-planning models, as well as comprehensive models for quality management systems. There are also critical underlying issues, such as an emphasis on MU to the possible exclusion of TAE and a corresponding preference for separate precision and bias goals instead of a combined total error goal. This opinion recommends careful consideration of the differences in the concepts of accuracy and traceability and the appropriateness of different measures, particularly TAE as a measure of accuracy and MU as a measure of traceability. TAE is essential to manage quality within a medical laboratory and MU and trueness are essential to achieve comparability of results across laboratories. With this perspective, laboratory scientists can better understand the many measures and models needed for analytical quality management and assess their usefulness for practical applications in medical laboratories. PMID:26426893

  15. A Flexible Two-Part Random Effects Model for Correlated Medical Costs

    PubMed Central

    Liu, Lei; Cowen, Mark E.; Strawderman, Robert L.; Shih, Ya-Chen T.

    2009-01-01

    In this paper, we propose a flexible “two-part” random Effects model (Olsen and Schafer 2001; Tooze, Grunwald, and Jones 2002) for correlated medical cost data. Typically, medical cost data are right-skewed, involve a substantial proportion of zero values, and may exhibit heteroscedasticity. In many cases, such data is also obtained in hierarchical form, e.g., on patients served by the same physician. The proposed model specification therefore consists of two generalized linear mixed models (GLMM), linked together by correlated random Effects. Respectively, and conditionally on the random Effects and covariates, we model the odds of cost being positive (Part I) using a GLMM with a logistic link and the mean cost (Part II) given that costs were actually incurred using a generalized gamma regression model with random Effects and a scale parameter that is allowed to depend on covariates (c.f. Manning, Basu, and Mullahy 2005). The class of generalized gamma distributions is very flexible and includes the lognormal, gamma, inverse gamma and Weibull distributions as special cases. We demonstrate how to carry out estimation using the Gaussian quadrature techniques conveniently implemented in SAS Proc NLMIXED. The proposed model is used to analyze pharmacy cost data on 56,245 adult patients clustered within 239 physicians in a mid-western U.S. managed care organization. PMID:20015560

  16. Multi-object segmentation framework using deformable models for medical imaging analysis.

    PubMed

    Namías, Rafael; D'Amato, Juan Pablo; Del Fresno, Mariana; Vénere, Marcelo; Pirró, Nicola; Bellemare, Marc-Emmanuel

    2016-08-01

    Segmenting structures of interest in medical images is an important step in different tasks such as visualization, quantitative analysis, simulation, and image-guided surgery, among several other clinical applications. Numerous segmentation methods have been developed in the past three decades for extraction of anatomical or functional structures on medical imaging. Deformable models, which include the active contour models or snakes, are among the most popular methods for image segmentation combining several desirable features such as inherent connectivity and smoothness. Even though different approaches have been proposed and significant work has been dedicated to the improvement of such algorithms, there are still challenging research directions as the simultaneous extraction of multiple objects and the integration of individual techniques. This paper presents a novel open-source framework called deformable model array (DMA) for the segmentation of multiple and complex structures of interest in different imaging modalities. While most active contour algorithms can extract one region at a time, DMA allows integrating several deformable models to deal with multiple segmentation scenarios. Moreover, it is possible to consider any existing explicit deformable model formulation and even to incorporate new active contour methods, allowing to select a suitable combination in different conditions. The framework also introduces a control module that coordinates the cooperative evolution of the snakes and is able to solve interaction issues toward the segmentation goal. Thus, DMA can implement complex object and multi-object segmentations in both 2D and 3D using the contextual information derived from the model interaction. These are important features for several medical image analysis tasks in which different but related objects need to be simultaneously extracted. Experimental results on both computed tomography and magnetic resonance imaging show that the proposed

  17. A Low-Cost Teaching Model of Inguinal Canal: A Useful Method to Teach Surgical Concepts in Hernia Repair

    ERIC Educational Resources Information Center

    Ansaloni, Luca; Catena, Fausto; Coccolini, Frederico; Ceresoli, Marco; Pinna, Antonio Daniele

    2014-01-01

    Objectives: Inguinal canal anatomy and hernia repair is difficult for medical students and surgical residents to comprehend. Methods: Using low-cost material, a 3-dimensional inexpensive model of the inguinal canal was created to allow students to learn anatomical details and landmarks and to perform their own simulated hernia repair. In order to…

  18. OntoVIP: an ontology for the annotation of object models used for medical image simulation.

    PubMed

    Gibaud, Bernard; Forestier, Germain; Benoit-Cattin, Hugues; Cervenansky, Frédéric; Clarysse, Patrick; Friboulet, Denis; Gaignard, Alban; Hugonnard, Patrick; Lartizien, Carole; Liebgott, Hervé; Montagnat, Johan; Tabary, Joachim; Glatard, Tristan

    2014-12-01

    This paper describes the creation of a comprehensive conceptualization of object models used in medical image simulation, suitable for major imaging modalities and simulators. The goal is to create an application ontology that can be used to annotate the models in a repository integrated in the Virtual Imaging Platform (VIP), to facilitate their sharing and reuse. Annotations make the anatomical, physiological and pathophysiological content of the object models explicit. In such an interdisciplinary context we chose to rely on a common integration framework provided by a foundational ontology, that facilitates the consistent integration of the various modules extracted from several existing ontologies, i.e. FMA, PATO, MPATH, RadLex and ChEBI. Emphasis is put on methodology for achieving this extraction and integration. The most salient aspects of the ontology are presented, especially the organization in model layers, as well as its use to browse and query the model repository. PMID:25038553

  19. A Model Optimization Approach to the Automatic Segmentation of Medical Images

    NASA Astrophysics Data System (ADS)

    Afifi, Ahmed; Nakaguchi, Toshiya; Tsumura, Norimichi; Miyake, Yoichi

    The aim of this work is to develop an efficient medical image segmentation technique by fitting a nonlinear shape model with pre-segmented images. In this technique, the kernel principle component analysis (KPCA) is used to capture the shape variations and to build the nonlinear shape model. The pre-segmentation is carried out by classifying the image pixels according to the high level texture features extracted using the over-complete wavelet packet decomposition. Additionally, the model fitting is completed using the particle swarm optimization technique (PSO) to adapt the model parameters. The proposed technique is fully automated, is talented to deal with complex shape variations, can efficiently optimize the model to fit the new cases, and is robust to noise and occlusion. In this paper, we demonstrate the proposed technique by implementing it to the liver segmentation from computed tomography (CT) scans and the obtained results are very hopeful.

  20. Research on an Improved Medical Image Enhancement Algorithm Based on P-M Model.

    PubMed

    Dong, Beibei; Yang, Jingjing; Hao, Shangfu; Zhang, Xiao

    2015-01-01

    Image enhancement can improve the detail of the image and so as to achieve the purpose of the identification of the image. At present, the image enhancement is widely used in medical images, which can help doctor's diagnosis. IEABPM (Image Enhancement Algorithm Based on P-M Model) is one of the most common image enhancement algorithms. However, it may cause the lost of the texture details and other features. To solve the problems, this paper proposes an IIEABPM (Improved Image Enhancement Algorithm Based on P-M Model). Simulation demonstrates that IIEABPM can effectively solve the problems of IEABPM, and improve image clarity, image contrast, and image brightness. PMID:26628929

  1. Using case studies based on a nursing conceptual model to teach medical-surgical nursing.

    PubMed

    DeSanto-Madeya, Susan

    2007-10-01

    Nurse educators are continually challenged to develop teaching strategies that enhance students' critical thinking, problem-solving, and decision-making skills. Case studies are a creative learning strategy that fosters these skills through the use of in-depth descriptions of realistic clinical situations. Conceptual models of nursing provide a unique body of knowledge that can be used to guide construction of case studies and enhance application of didactic course content to nursing practice. In this column, the author discusses the use of case studies constructed within the context of the Roy adaptation model for a senior level medical-surgical nursing course. PMID:17911329

  2. Measuring product meaning for prescribed medication using a means-end chain model.

    PubMed

    Doucette, W R; Wiederholt, J B

    1992-03-01

    On the basis of a means-end chain model, the product attribute and consequence levels of consumers' product meaning for prescribed medication were measured for a sample of 550 consumers. Using exploratory factor analysis on a 30-item scale, the authors identified five product attribute dimensions and three consequence dimensions. The means-end chain model can help marketers of health care learn more about how consumers categorize product meanings, which in turn can be used in the development of marketing strategies. PMID:10116755

  3. Patterned 3-dimensional metal grid electrodes as alternative electron collectors in dye-sensitized solar cells.

    PubMed

    Chua, Julianto; Mathews, Nripan; Jennings, James R; Yang, Guangwu; Wang, Qing; Mhaisalkar, Subodh G

    2011-11-21

    We describe the application of 3-dimensional metal grid electrodes (3D-MGEs) as electron collectors in dye-sensitized solar cells (DSCs) as a replacement for fluorinated tin oxide (FTO) electrodes. Requirements, structure, advantages, and limitations of the metal grid electrodes are discussed. Solar conversion efficiencies of 6.2% have been achieved in 3D-MGE based solar cells, comparable to that fabricated on FTO (7.1%). The charge transport properties and collection efficiencies in these novel solar cells have been studied using electrochemical impedance spectroscopy. PMID:21989708

  4. International "Intercomparison of 3-Dimensional (3D) Radiation Codes" (13RC)

    NASA Technical Reports Server (NTRS)

    Cahalan, Robert F.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    An international "Intercomparison of 3-dimensional (3D) Radiation Codes" 13RC) has been initiated. It is endorsed by the GEWEX Radiation Panel, and funded jointly by the United States Department of Energy ARM program, and by the National Aeronautics and Space Administration Radiation Sciences program. It is a 3-phase effort that has as its goals to: (1) understand the errors and limits of 3D methods; (2) provide 'baseline' cases for future 3D code development; (3) promote sharing of 3D tools; (4) derive guidelines for 3D tool selection; and (5) improve atmospheric science education in 3D radiation.

  5. High-speed 3-dimensional imaging in robot-assisted thoracic surgical procedures.

    PubMed

    Kajiwara, Naohiro; Akata, Soichi; Hagiwara, Masaru; Yoshida, Koichi; Kato, Yasufumi; Kakihana, Masatoshi; Ohira, Tatsuo; Kawate, Norihiko; Ikeda, Norihiko

    2014-06-01

    We used a high-speed 3-dimensional (3D) image analysis system (SYNAPSE VINCENT, Fujifilm Corp, Tokyo, Japan) to determine the best positioning of robotic arms and instruments preoperatively. The da Vinci S (Intuitive Surgical Inc, Sunnyvale, CA) was easily set up accurately and rapidly for this operation. Preoperative simulation and intraoperative navigation using the SYNAPSE VINCENT for robot-assisted thoracic operations enabled efficient planning of the operation settings. The SYNAPSE VINCENT can detect the tumor location and depict surrounding tissues quickly, accurately, and safely. This system is also excellent for navigational and educational use. PMID:24882302

  6. Evaluation of Temperature and Stress Distribution on 2 Different Post Systems Using 3-Dimensional Finite Element Analysis

    PubMed Central

    Değer, Yalçın; Adigüzel, Özkan; Özer, Senem Yiğit; Kaya, Sadullah; Polat, Zelal Seyfioğlu; Bozyel, Bejna

    2015-01-01

    Background The mouth is exposed to thermal irritation from hot and cold food and drinks. Thermal changes in the oral cavity produce expansions and contractions in tooth structures and restorative materials. The aim of this study was to investigate the effect of temperature and stress distribution on 2 different post systems using the 3-dimensional (3D) finite element method. Material/Methods The 3D finite element model shows a labio-lingual cross-sectional view of the endodontically treated upper right central incisor and supporting periodontal ligament with bone structures. Stainless steel and glass fiber post systems with different physical and thermal properties were modelled in the tooth restored with composite core and ceramic crown. We placed 100 N static vertical occlusal loading onto the center of the incisal surface of the tooth. Thermal loads of 0°C and 65°C were applied on the model for 5 s. Temperature and thermal stresses were determined on the labio-lingual section of the model at 6 different points. Results The distribution of stress, including thermal stress values, was calculated using 3D finite element analysis. The stainless steel post system produced more temperature and thermal stresses on the restorative materials, tooth structures, and posts than did the glass fiber reinforced composite posts. Conclusions Thermal changes generated stresses in the restorative materials, tooth, and supporting structures. PMID:26615495

  7. The Economics of Improving Medication Adherence in Osteoporosis: Validation and Application of a Simulation Model

    PubMed Central

    Schousboe, John T.; Losina, Elena; Solomon, Daniel H.

    2011-01-01

    Context: Adherence to osteoporosis treatment is low. Although new therapies and behavioral interventions may improve medication adherence, questions are likely to arise regarding their cost-effectiveness. Objective: Our objectives were to develop and validate a model to simulate the clinical outcomes and costs arising from various osteoporosis medication adherence patterns among women initiating bisphosphonate treatment and to estimate the cost-effectiveness of a hypothetical intervention to improve medication adherence. Design: We constructed a computer simulation using estimates of fracture rates, bisphosphonate treatment effects, costs, and utilities for health states drawn from the published literature. Probabilities of transitioning on and off treatment were estimated from administrative claims data. Setting and Patients: Patients were women initiating bisphosphonate therapy from the general community. Intervention: We evaluated a hypothetical behavioral intervention to improve medication adherence. Main Outcome Measures: Changes in 10-yr fracture rates and incremental cost-effectiveness ratios were evaluated. Results: A hypothetical intervention with a one-time cost of $250 and reducing bisphosphonate discontinuation by 30% had an incremental cost-effectiveness ratio (ICER) of $29,571 per quality-adjusted life year in 65-yr-old women initiating bisphosphonates. Although the ICER depended on patient age, intervention effectiveness, and intervention cost, the ICERs were less than $50,000 per quality-adjusted life year for the majority of intervention cost and effectiveness scenarios evaluated. Results were sensitive to bisphosphonate cost and effectiveness and assumptions about the rate at which intervention and treatment effects decline over time. Conclusions: Our results suggests that behavioral interventions to improve osteoporosis medication adherence will likely have favorable ICERs if their efficacy can be sustained. PMID:21733991

  8. The medical decision model and decision maker tools for management of radiological and nuclear incidents.

    PubMed

    Koerner, John F; Coleman, C Norman; Murrain-Hill, Paula; FitzGerald, Denis J; Sullivan, Julie M

    2014-06-01

    Effective decision making during a rapidly evolving emergency such as a radiological or nuclear incident requires timely interim decisions and communications from onsite decision makers while further data processing, consultation, and review are ongoing by reachback experts. The authors have recently proposed a medical decision model for use during a radiological or nuclear disaster, which is similar in concept to that used in medical care, especially when delay in action can have disastrous effects. For decision makers to function most effectively during a complex response, they require access to onsite subject matter experts who can provide information, recommendations, and participate in public communication efforts. However, in the time before this expertise is available or during the planning phase, just-in-time tools are essential that provide critical overview of the subject matter written specifically for the decision makers. Recognizing the complexity of the science, risk assessment, and multitude of potential response assets that will be required after a nuclear incident, the Office of the Assistant Secretary for Preparedness and Response, in collaboration with other government and non-government experts, has prepared a practical guide for decision makers. This paper illustrates how the medical decision model process could facilitate onsite decision making that includes using the deliberative reachback process from science and policy experts and describes the tools now available to facilitate timely and effective incident management. PMID:24776895

  9. An Overview of Mechanical Properties and Material Modeling of Polylactide (PLA) for Medical Applications.

    PubMed

    Bergström, Jörgen S; Hayman, Danika

    2016-02-01

    This article provides an overview of the connection between the microstructural state and the mechanical response of various bioresorbable polylactide (PLA) devices for medical applications. PLLA is currently the most commonly used material for bioresorbable stents and sutures, and its use is increasing in many other medical applications. The non-linear mechanical response of PLLA, due in part to its low glass transition temperature (T g ≈ 60 °C), is highly sensitive to the molecular weight and molecular orientation field, the degree of crystallinity, and the physical aging time. These microstructural parameters can be tailored for specific applications using different resin formulations and processing conditions. The stress-strain, deformation, and degradation response of a bioresorbable medical device is also strongly dependent on the time history of applied loads and boundary conditions. All of these factors can be incorporated into a suitable constitutive model that captures the multiple physics that are involved in the device response. Currently developed constitutive models already provide powerful computations simulation tools, and more progress in this area is expected to occur in the coming years. PMID:26369638

  10. The successful, rapid transition to a new model of graduate medical education in Singapore.

    PubMed

    Huggan, Paul J; Samarasekara, Dujeepa D; Archuleta, Sophia; Khoo, See Meng; Sim, Joe Heng Joo; Sin, Clara Siew Ping; Ooi, Shirley Beng Suat

    2012-09-01

    Graduate medical education (GME) in Singapore recently underwent major reform (2009-2012), leading to accreditation of residency programs by the Accreditation Council for Graduate Medical Education-International (ACGME-I) within two years of the initial commitment to change. The main aims of the reforms were to implement best practices in GME, to provide better support structures for program administration, and to bring all specialty training under one administrative umbrella. The authors outline the historic development of GME in Singapore, the complexities of the model in place immediately prior to ACGME-I accreditation, and the difficulties addressed by the proposed changes, leading to a description of implementation efforts at the National University Hospital of Singapore, a university-affiliated academic medical center. The authors describe the institutional factors uniting hospital leaders in support of reform, the recruitment of a team to manage change within the institution, the inauguration of a new office for GME, and the faculty development initiatives needed to educate faculty leading the change process. The preparation and execution of specific initiatives designed to improve GME and the communication strategies needed to coordinate and publicize change efforts are outlined, as well as strategies for sustaining improvements and building them into the culture of the institution. The authors demonstrate that external accreditation can be a powerful driver of educational reform and summarize key lessons derived from Kotter principles, a current model of change management. PMID:22836841

  11. A model approach to sharing electronic medical records between and within the state hospitals in Turkey.

    PubMed

    Güler, I; Müldür, S

    2001-11-01

    It has always been a research interest to solve hospital management problems with systematic approach by using modern management tools. Almost all the Hospital Information System (HIS) software packages in Turkey keep track of local transactions in administrative activities and material flow. In state hospitals in Turkey, very little medical information is processed and most of the records are still kept manually and archived on papers. In this paper, a cost-effective, flexible and easy-to-use Hospital Information System model is proposed in order to give better diagnostic and treatment services. It is also demonstrated that this model makes it possible to exchange information between and within the hospitals over Transmission Control Protocol/Internet Protocol (TCP/IP) network. User needs are taken into consideration during model development and the benefits of model implementation to the hospital administration are stated. According to the model proposed in this paper, only a single health care record number (HCRN) is required for a patient to access all her/his medical records stored in different locations, from any state hospital in Turkey. PMID:11604155

  12. Improving Education in Medical Statistics: Implementing a Blended Learning Model in the Existing Curriculum

    PubMed Central

    Milic, Natasa M.; Trajkovic, Goran Z.; Bukumiric, Zoran M.; Cirkovic, Andja; Nikolic, Ivan M.; Milin, Jelena S.; Milic, Nikola V.; Savic, Marko D.; Corac, Aleksandar M.; Marinkovic, Jelena M.; Stanisavljevic, Dejana M.

    2016-01-01

    Background Although recent studies report on the benefits of blended learning in improving medical student education, there is still no empirical evidence on the relative effectiveness of blended over traditional learning approaches in medical statistics. We implemented blended along with on-site (i.e. face-to-face) learning to further assess the potential value of web-based learning in medical statistics. Methods This was a prospective study conducted with third year medical undergraduate students attending the Faculty of Medicine, University of Belgrade, who passed (440 of 545) the final exam of the obligatory introductory statistics course during 2013–14. Student statistics achievements were stratified based on the two methods of education delivery: blended learning and on-site learning. Blended learning included a combination of face-to-face and distance learning methodologies integrated into a single course. Results Mean exam scores for the blended learning student group were higher than for the on-site student group for both final statistics score (89.36±6.60 vs. 86.06±8.48; p = 0.001) and knowledge test score (7.88±1.30 vs. 7.51±1.36; p = 0.023) with a medium effect size. There were no differences in sex or study duration between the groups. Current grade point average (GPA) was higher in the blended group. In a multivariable regression model, current GPA and knowledge test scores were associated with the final statistics score after adjusting for study duration and learning modality (p<0.001). Conclusion This study provides empirical evidence to support educator decisions to implement different learning environments for teaching medical statistics to undergraduate medical students. Blended and on-site training formats led to similar knowledge acquisition; however, students with higher GPA preferred the technology assisted learning format. Implementation of blended learning approaches can be considered an attractive, cost-effective, and efficient

  13. Putting patients first: a novel patient-centered model for medical enterprise success.

    PubMed

    Dhawan, Naveen

    2014-01-01

    This article introduces a new way of viewing patient-customers. It encourages a greater emphasis on patients' needs and the importance of considering dimensions of the patient experience to better serve them. It also draws from examples in the general business world as they can be applied to medical enterprises. The author introduces a model that directs all business activities toward the end consumer with an underlying guidance by patient needs. A business is advised to understand its customer, design a patient-directed vision, and focus on creating a unique customer experience. The article delineates key action items for physicians and administrators that will allow them to better meet their patient-customers' needs and develop loyalty. By practicing a patient-centered approach and following these guidelines, one may ensure greater success of the medical enterprise. PMID:25108980

  14. Are tax subsidies for private medical insurance self-financing? Evidence from a microsimulation model.

    PubMed

    López Nicolás, Angel; Vera-Hernández, Marcos

    2008-09-01

    This paper develops an empirical strategy to estimate whether subsidies to private medical insurance are self-financing in countries where public and private insurance coexist and the latter covers the same treatments as the former. We construct a simulation routine based on a micro-econometric discrete choice model that allows us to evaluate the impact of premium changes on the utilization of outpatient and inpatient health care services. As an application, we estimate the budgetary effects of scrapping a subsidy from the purchase of individual private policies, using micro-data from Catalonia. Our results suggest that the subsidy is not self-financing. This result is driven by the fact that private medical insurance holders make concurrent use of public and private services, and by the price inelasticity of the demand for private policies. PMID:18692262

  15. Role Modeling in Medical Education: The Importance of a Reflective Imitation

    PubMed Central

    2014-01-01

    The medical literature almost uniformly addresses the positive aspects of role modeling. Still, some authors have questioned its educational value, a disagreement that is probably due to differing definitions of role modeling. If defined as demonstration of skills, provision of feedback, and emulation of specific professional behaviors, then role modeling is an important component of clinical training. However, if it is defined as a learner’s unselective imitation of role models and uncritical adoption of the messages of the learning environment, then the benefits of role modeling should be weighed against its unintended harm. In this Perspective, the author argues that imitation of role models may initially help students adapt to the clinical environment. However, if sustained, imitation may perpetuate undesirable practices, such as doctor-centered patient interviewing, and unintended institutional norms, such as discrimination between private and public patients. The author suggests that the value of role modeling can be advanced not only by targeting role models and improving faculty performance but also by enhancing students’ reflective assessment of their preceptors’ behaviors, especially so that they can better discern those that are worth imitating. This student-centered approach may be accomplished by first, warning students against uncritically imitating preceptors who are perceived as role models; second, showing students that their preceptors share their doubts and uncertainties; third, gaining an insight into possible undesirable messages of the learning environment; and finally, developing policies for faculty recruitment and promotion that consider whether a clinical preceptor is a role model. PMID:24556777

  16. Model selection for a medical diagnostic decision support system: a breast cancer detection case.

    PubMed

    West, D; West, V

    2000-11-01

    There are a number of different quantitative models that can be used in a medical diagnostic decision support system (MDSS) including parametric methods (linear discriminant analysis or logistic regression), non-parametric models (K nearest neighbor, or kernel density) and several neural network models. The complexity of the diagnostic task is thought to be one of the prime determinants of model selection. Unfortunately, there is no theory available to guide model selection. Practitioners are left to either choose a favorite model or to test a small subset using cross validation methods. This paper illustrates the use of a self-organizing map (SOM) to guide model selection for a breast cancer MDSS. The topological ordering properties of the SOM are used to define targets for an ideal accuracy level similar to a Bayes optimal level. These targets can then be used in model selection, variable reduction, parameter determination, and to assess the adequacy of the clinical measurement system. These ideas are applied to a successful model selection for a real-world breast cancer database. Diagnostic accuracy results are reported for individual models, for ensembles of neural networks, and for stacked predictors. PMID:10998586

  17. A New Model for the Organizational Structure of Medical Record Departments in Hospitals in Iran

    PubMed Central

    Moghaddasi, Hamid; Hosseini, Azamossadat; Sheikhtaheri, Abbas

    2006-01-01

    The organizational structure of medical record departments in Iran is not appropriate for the efficient management of healthcare information. In addition, there is no strong information management division to provide comprehensive information management services in hospitals in Iran. Therefore, a suggested model was designed based on four main axes: 1) specifications of a Health Information Management Division, 2) specifications of a Healthcare Information Management Department, 3) the functions of the Healthcare Information Management Department, and 4) the units of the Healthcare Information Management Department. The validity of the model was determined through use of the Delphi technique. The results of the validation process show that the majority of experts agree with the model and consider it to be appropriate and applicable for hospitals in Iran. The model is therefore recommended for hospitals in Iran. PMID:18066362

  18. A new model for the organizational structure of medical record departments in hospitals in Iran.

    PubMed

    Moghaddasi, Hamid; Hosseini, Azamossadat; Sheikhtaheri, Abbas

    2006-01-01

    The organizational structure of medical record departments in Iran is not appropriate for the efficient management of healthcare information. In addition, there is no strong information management division to provide comprehensive information management services in hospitals in Iran. Therefore, a suggested model was designed based on four main axes: 1) specifications of a Health Information Management Division, 2) specifications of a Healthcare Information Management Department, 3) the functions of the Healthcare Information Management Department, and 4) the units of the Healthcare Information Management Department. The validity of the model was determined through use of the Delphi technique. The results of the validation process show that the majority of experts agree with the model and consider it to be appropriate and applicable for hospitals in Iran. The model is therefore recommended for hospitals in Iran. PMID:18066362

  19. Identification of a potential fibromyalgia diagnosis using random forest modeling applied to electronic medical records

    PubMed Central

    Emir, Birol; Masters, Elizabeth T; Mardekian, Jack; Clair, Andrew; Kuhn, Max; Silverman, Stuart L

    2015-01-01

    Background Diagnosis of fibromyalgia (FM), a chronic musculoskeletal condition characterized by widespread pain and a constellation of symptoms, remains challenging and is often delayed. Methods Random forest modeling of electronic medical records was used to identify variables that may facilitate earlier FM identification and diagnosis. Subjects aged ≥18 years with two or more listings of the International Classification of Diseases, Ninth Revision, (ICD-9) code for FM (ICD-9 729.1) ≥30 days apart during the 2012 calendar year were defined as cases among subjects associated with an integrated delivery network and who had one or more health care provider encounter in the Humedica database in calendar years 2011 and 2012. Controls were without the FM ICD-9 codes. Seventy-two demographic, clinical, and health care resource utilization variables were entered into a random forest model with downsampling to account for cohort imbalances (<1% subjects had FM). Importance of the top ten variables was ranked based on normalization to 100% for the variable with the largest loss in predicting performance by its omission from the model. Since random forest is a complex prediction method, a set of simple rules was derived to help understand what factors drive individual predictions. Results The ten variables identified by the model were: number of visits where laboratory/non-imaging diagnostic tests were ordered; number of outpatient visits excluding office visits; age; number of office visits; number of opioid prescriptions; number of medications prescribed; number of pain medications excluding opioids; number of medications administered/ordered; number of emergency room visits; and number of musculoskeletal conditions. A receiver operating characteristic curve confirmed the model’s predictive accuracy using an independent test set (area under the curve, 0.810). To enhance interpretability, nine rules were developed that could be used with good predictive probability of

  20. A New 3-Dimensional Dynamic Quantitative Analysis System of Facial Motion: An Establishment and Reliability Test

    PubMed Central

    Feng, Guodong; Zhao, Yang; Tian, Xu; Gao, Zhiqiang

    2014-01-01

    This study aimed to establish a 3-dimensional dynamic quantitative facial motion analysis system, and then determine its accuracy and test-retest reliability. The system could automatically reconstruct the motion of the observational points. Standardized T-shaped rod and L-shaped rods were used to evaluate the static and dynamic accuracy of the system. Nineteen healthy volunteers were recruited to test the reliability of the system. The average static distance error measurement was 0.19 mm, and the average angular error was 0.29°. The measuring results decreased with the increase of distance between the cameras and objects, 80 cm of which was considered to be optimal. It took only 58 seconds to perform the full facial measurement process. The average intra-class correlation coefficient for distance measurement and angular measurement was 0.973 and 0.794 respectively. The results demonstrated that we successfully established a practical 3-dimensional dynamic quantitative analysis system that is accurate and reliable enough to meet both clinical and research needs. PMID:25390881

  1. A customizable 3-dimensional digital atlas of the canary brain in multiple modalities.

    PubMed

    Vellema, Michiel; Verschueren, Jacob; Van Meir, Vincent; Van der Linden, Annemie

    2011-07-15

    Songbirds are well known for their ability to learn their vocalizations by imitating conspecific adults. This uncommon skill has led to many studies examining the behavioral and neurobiological processes involved in vocal learning. Canaries display a variable, seasonally dependent, vocal behavior throughout their lives. This trait makes this bird species particularly valuable to study the functional relationship between the continued plasticity in the singing behavior and alterations in the anatomy and physiology of the brain. In order to optimally interpret these types of studies, a detailed understanding of the brain anatomy is essential. Because traditional 2-dimensional brain atlases are limited in the information they can provide about the anatomy of the brain, here we present a 3-dimensional MRI-based atlas of the canary brain. Using multiple imaging protocols we were able to maximize the number of detectable brain regions, including most of the areas involved in song perception, learning, and production. The brain atlas can readily be used to determine the stereotactic location of delineated brain areas at any desirable head angle. Alternatively the brain data can be used to determine the ideal orientation of the brain for stereotactic injections, electrophysiological recordings, and brain sectioning. The 3-dimensional canary brain atlas presented here is freely available and is easily adaptable to support many types of neurobiological studies, including anatomical, electrophysiological, histological, explant, and tracer studies. PMID:21565273

  2. Realization of integral 3-dimensional image using fabricated tunable liquid lens array

    NASA Astrophysics Data System (ADS)

    Lee, Muyoung; Kim, Junoh; Kim, Cheol Joong; Lee, Jin Su; Won, Yong Hyub

    2015-03-01

    Electrowetting has been widely studied for various optical applications such as optical switch, sensor, prism, and display. In this study, vari-focal liquid lens array is developed using electrowetting principle to construct integral 3-dimensional imaging. The electrowetting principle that changes the surface tension by applying voltage has several advantages to realize active optical device such as fast response time, low electrical consumption, and no mechanical moving parts. Two immiscible liquids that are water and oil are used for forming lens. By applying a voltage to the water, the focal length of the lens could be tuned as changing contact angle of water. The fabricated electrowetting vari-focal liquid lens array has 1mm diameter spherical lens shape that has 1.6mm distance between each lens. The number of lenses on the panel is 23x23 and the focal length of the lens array is simultaneously tuned from -125 to 110 diopters depending on the applied voltage. The fabricated lens array is implemented to integral 3-dimensional imaging. A 3D object is reconstructed by fabricated liquid lens array with 23x23 elemental images that are generated by 3D max tools. When liquid lens array is tuned as convex state. From vari-focal liquid lens array implemented integral imaging system, we expect that depth enhanced integral imaging can be realized in the near future.

  3. Morphological Control of Cells on 3-Dimensional Multi-Layer Nanotopographic Structures.

    PubMed

    Jeong, Heon-Ho; Noh, Young-Mu; Song, Hwan-Moon; Lee, Sang-Ho; Park, Jin-Sung; Lee, Chang-Soo

    2015-05-01

    The extracellular matrix (ECM) environment is known to play an important role in the process of various cell regulatory mechanisms. We have investigated the ability of 3-dimensional ECM geometries to induce morphological changes in cells. Bi-layer polymeric structures with submicron scale stripe patterns were fabricated using a two-step nano-imprinting technique, and the orientation angle (θ(α)) of the upper layer was controlled by changing its alignment with respect to the orientation of the bottom layer. When cells were grown on the mono-layer stripe structure with a single orientation, they elongated along the direction of the stripe pattern. On bi-layer polymer structures, the cell morphologies gradually changed and became rounded, with an increase of θα up to 90 degrees, but the polarities of these cells were still aligned along the orientation of the upper layer. As a result, we show that the polarity and the roundness of cells can be independently regulated by adjusting the orientation of 3-dimensional hierarchical ECM topography. PMID:26505024

  4. Particle trajectory computation on a 3-dimensional engine inlet. Final Report Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Kim, J. J.

    1986-01-01

    A 3-dimensional particle trajectory computer code was developed to compute the distribution of water droplet impingement efficiency on a 3-dimensional engine inlet. The computed results provide the essential droplet impingement data required for the engine inlet anti-icing system design and analysis. The droplet trajectories are obtained by solving the trajectory equation using the fourth order Runge-Kutta and Adams predictor-corrector schemes. A compressible 3-D full potential flow code is employed to obtain a cylindrical grid definition of the flowfield on and about the engine inlet. The inlet surface is defined mathematically through a system of bi-cubic parametric patches in order to compute the droplet impingement points accurately. Analysis results of the 3-D trajectory code obtained for an axisymmetric droplet impingement problem are in good agreement with NACA experimental data. Experimental data are not yet available for the engine inlet impingement problem analyzed. Applicability of the method to solid particle impingement problems, such as engine sand ingestion, is also demonstrated.

  5. Joint Modelling of Survival and Emergency Medical Care Usage in Spanish Insureds Aged 65+

    PubMed Central

    2016-01-01

    Background We study the longevity and medical resource usage of a large sample of insureds aged 65 years or older drawn from a large health insurance dataset. Yearly counts of each subject's emergency room and ambulance service use and hospital admissions are made. Occurrence of mortality is also monitored. The study aims to capture the simultaneous dependence between their demand for healthcare and survival. Methods We demonstrate the benefits of taking a joint approach to modelling longitudinal and survival processes by using a large dataset from a Spanish medical mutual company. This contains historical insurance information for 39,137 policyholders aged 65+ (39.5% men and 60.5% women) across the eight-year window of the study. The joint model proposed incorporates information on longitudinal demand for care in a weighted cumulative effect that places greater emphasis on more recent than on past service demand. Results A strong significant and positive relationship between the exponentially weighted demand for emergency, ambulance and hospital services is found with risk of death (alpha = 1.462, p < 0.001). Alternative weighting specifications are tested, but in all cases they show that a joint approach indicates a close connection between health care demand and time-to-death. Additionally, the model allows us to predict individual survival curves dynamically as new information on demand for services becomes known. Conclusions The joint model fitted demonstrates the utility of analysing demand for medical services and survival simultaneously. Likewise, it allows the personalized prediction of survival in advanced age subjects. PMID:27073868

  6. Medical cost-offset following treatment referral for alcohol and other drug use disorders in a group model HMO.

    PubMed

    Polen, Michael R; Freeborn, Donald K; Lynch, Frances L; Mullooly, John P; Dickinson, Daniel M

    2006-07-01

    The purpose of this study was to determine whether specialty alcohol and other drug (AOD) treatment is associated with reduced subsequent medical care costs. AOD treatment costs and medical costs in a group model health maintenance organization (HMO) were collected for up to 6 years on 1,472 HMO members who were recommended for specialty AOD treatment, and on 738 members without AOD diagnoses or treatment. Addiction Severity Index measures were also obtained from a sample of 293 of those recommended for treatment. Changes in medical costs did not differ between treatment and comparison groups. Nor did individuals with improved treatment outcomes have greater reductions in medical costs. AOD treatment costs were not inversely related to subsequent medical costs, except for a subgroup with recent AOD treatment. In the interviewed sample, better treatment outcomes did not predict lower subsequent medical costs. Multiple treatment episodes may hold promise for producing cost-offsets. PMID:16752110

  7. Modeled occupational exposures to gas-phase medical laser-generated air contaminants.

    PubMed

    Lippert, Julia F; Lacey, Steven E; Jones, Rachael M

    2014-01-01

    Exposure monitoring data indicate the potential for substantive exposure to laser-generated air contaminants (LGAC); however the diversity of medical lasers and their applications limit generalization from direct workplace monitoring. Emission rates of seven previously reported gas-phase constituents of medical laser-generated air contaminants (LGAC) were determined experimentally and used in a semi-empirical two-zone model to estimate a range of plausible occupational exposures to health care staff. Single-source emission rates were generated in an emission chamber as a one-compartment mass balance model at steady-state. Clinical facility parameters such as room size and ventilation rate were based on standard ventilation and environmental conditions required for a laser surgical facility in compliance with regulatory agencies. All input variables in the model including point source emission rates were varied over an appropriate distribution in a Monte Carlo simulation to generate a range of time-weighted average (TWA) concentrations in the near and far field zones of the room in a conservative approach inclusive of all contributing factors to inform future predictive models. The concentrations were assessed for risk and the highest values were shown to be at least three orders of magnitude lower than the relevant occupational exposure limits (OELs). Estimated values do not appear to present a significant exposure hazard within the conditions of our emission rate estimates. PMID:24762065

  8. Improving medical diagnostic accuracy of ultrasound Doppler signals by combining neural network models.

    PubMed

    Ubeyli, Elif Derya; Güler, Inan

    2005-07-01

    There are a number of different quantitative models that can be used in a medical diagnostic decision support system including parametric methods (linear discriminant analysis or logistic regression), nonparametric models (k nearest neighbor or kernel density) and several neural network models. The complexity of the diagnostic task is thought to be one of the prime determinants of model selection. Unfortunately, there is no theory available to guide model selection. This paper illustrates the use of combined neural network models to guide model selection for diagnosis of ophthalmic and internal carotid arterial disorders. The ophthalmic and internal carotid arterial Doppler signals were decomposed into time-frequency representations using discrete wavelet transform and statistical features were calculated to depict their distribution. The first-level networks were implemented for the diagnosis of ophthalmic and internal carotid arterial disorders using the statistical features as inputs. To improve diagnostic accuracy, the second-level networks were trained using the outputs of the first-level networks as input data. The combined neural network models achieved accuracy rates which were higher than that of the stand-alone neural network models. PMID:15780863

  9. A High Performance Pulsatile Pump for Aortic Flow Experiments in 3-Dimensional Models.

    PubMed

    Chaudhury, Rafeed A; Atlasman, Victor; Pathangey, Girish; Pracht, Nicholas; Adrian, Ronald J; Frakes, David H

    2016-06-01

    Aortic pathologies such as coarctation, dissection, and aneurysm represent a particularly emergent class of cardiovascular diseases. Computational simulations of aortic flows are growing increasingly important as tools for gaining understanding of these pathologies, as well as for planning their surgical repair. In vitro experiments are required to validate the simulations against real world data, and the experiments require a pulsatile flow pump system that can provide physiologic flow conditions characteristic of the aorta. We designed a newly capable piston-based pulsatile flow pump system that can generate high volume flow rates (850 mL/s), replicate physiologic waveforms, and pump high viscosity fluids against large impedances. The system is also compatible with a broad range of fluid types, and is operable in magnetic resonance imaging environments. Performance of the system was validated using image processing-based analysis of piston motion as well as particle image velocimetry. The new system represents a more capable pumping solution for aortic flow experiments than other available designs, and can be manufactured at a relatively low cost. PMID:26983961

  10. Numerical model of electromagnetic scattering off a subterranean 3-dimensional dielectric

    SciTech Connect

    Dease, C.G.; Didwall, E.M.

    1983-08-01

    As part of the effort to develop On-Site Inspection (OSI) techniques for verification of compliance to a Comprehensive Test Ban Treaty (CTBT), a computer code was developed to predict the interaction of an electromagnetic (EM) wave with an underground cavity. Results from the code were used to evaluate the use of surface electromagnetic exploration techniques for detection of underground cavities or rubble-filled regions characteristic of underground nuclear explosions.

  11. A model of the pre-assessment learning effects of summative assessment in medical education.

    PubMed

    Cilliers, Francois J; Schuwirth, Lambert W T; Herman, Nicoline; Adendorff, Hanelie J; van der Vleuten, Cees P M

    2012-03-01

    It has become axiomatic that assessment impacts powerfully on student learning. However, surprisingly little research has been published emanating from authentic higher education settings about the nature and mechanism of the pre-assessment learning effects of summative assessment. Less still emanates from health sciences education settings. This study explored the pre-assessment learning effects of summative assessment in theoretical modules by exploring the variables at play in a multifaceted assessment system and the relationships between them. Using a grounded theory strategy, in-depth interviews were conducted with individual medical students and analyzed qualitatively. Respondents' learning was influenced by task demands and system design. Assessment impacted on respondents' cognitive processing activities and metacognitive regulation activities. Individually, our findings confirm findings from other studies in disparate non-medical settings and identify some new factors at play in this setting. Taken together, findings from this study provide, for the first time, some insight into how a whole assessment system influences student learning over time in a medical education setting. The findings from this authentic and complex setting paint a nuanced picture of how intricate and multifaceted interactions between various factors in an assessment system interact to influence student learning. A model linking the sources, mechanism and consequences of the pre-assessment learning effects of summative assessment is proposed that could help enhance the use of summative assessment as a tool to augment learning. PMID:21461880

  12. The Integrated Medical Model: A Risk Assessment and Decision Support Tool for Human Space Flight Missions

    NASA Technical Reports Server (NTRS)

    Kerstman, Eric L.; Minard, Charles; FreiredeCarvalho, Mary H.; Walton, Marlei E.; Myers, Jerry G., Jr.; Saile, Lynn G.; Lopez, Vilma; Butler, Douglas J.; Johnson-Throop, Kathy A.

    2011-01-01

    This slide presentation reviews the Integrated Medical Model (IMM) and its use as a risk assessment and decision support tool for human space flight missions. The IMM is an integrated, quantified, evidence-based decision support tool useful to NASA crew health and mission planners. It is intended to assist in optimizing crew health, safety and mission success within the constraints of the space flight environment for in-flight operations. It uses ISS data to assist in planning for the Exploration Program and it is not intended to assist in post flight research. The IMM was used to update Probability Risk Assessment (PRA) for the purpose of updating forecasts for the conditions requiring evacuation (EVAC) or Loss of Crew Life (LOC) for the ISS. The IMM validation approach includes comparison with actual events and involves both qualitative and quantitaive approaches. The results of these comparisons are reviewed. Another use of the IMM is to optimize the medical kits taking into consideration the specific mission and the crew profile. An example of the use of the IMM to optimize the medical kits is reviewed.

  13. Identifying the Basal Ganglia Network Model Markers for Medication-Induced Impulsivity in Parkinson's Disease Patients

    PubMed Central

    Balasubramani, Pragathi Priyadharsini; Chakravarthy, V. Srinivasa; Ali, Manal; Ravindran, Balaraman; Moustafa, Ahmed A.

    2015-01-01

    Impulsivity, i.e. irresistibility in the execution of actions, may be prominent in Parkinson's disease (PD) patients who are treated with dopamine precursors or dopamine receptor agonists. In this study, we combine clinical investigations with computational modeling to explore whether impulsivity in PD patients on medication may arise as a result of abnormalities in risk, reward and punishment learning. In order to empirically assess learning outcomes involving risk, reward and punishment, four subject groups were examined: healthy controls, ON medication PD patients with impulse control disorder (PD-ON ICD) or without ICD (PD-ON non-ICD), and OFF medication PD patients (PD-OFF). A neural network model of the Basal Ganglia (BG) that has the capacity to predict the dysfunction of both the dopaminergic (DA) and the serotonergic (5HT) neuromodulator systems was developed and used to facilitate the interpretation of experimental results. In the model, the BG action selection dynamics were mimicked using a utility function based decision making framework, with DA controlling reward prediction and 5HT controlling punishment and risk predictions. The striatal model included three pools of Medium Spiny Neurons (MSNs), with D1 receptor (R) alone, D2R alone and co-expressing D1R-D2R. Empirical studies showed that reward optimality was increased in PD-ON ICD patients while punishment optimality was increased in PD-OFF patients. Empirical studies also revealed that PD-ON ICD subjects had lower reaction times (RT) compared to that of the PD-ON non-ICD patients. Computational modeling suggested that PD-OFF patients have higher punishment sensitivity, while healthy controls showed comparatively higher risk sensitivity. A significant decrease in sensitivity to punishment and risk was crucial for explaining behavioral changes observed in PD-ON ICD patients. Our results highlight the power of computational modelling for identifying neuronal circuitry implicated in learning, and its

  14. MO-C-9A-01: Effective Medical Physics Educational Activities: Models and Methods

    SciTech Connect

    Sprawls, P

    2014-06-15

    Medical physics is learned in a combination of activities including classroom sessions, individual study, small-group collaborative problem solving, and direct experience in the laboratory or clinical environment. Each type of learning activity is characterized by its effectiveness in producing the desired knowledge for the learner and the cost in terms of resources and human effort required providing it. While learning and teaching is a human activity, modern technology provides a variety of tools that can be used to enhance human performance. The class or conference room is the common setting for educational sessions in both academic institutions and continuing education conferences and programs such as those sponsored by the AAPM. A major value of a class/conference room program is efficiency by bringing a group of learners together to share in a common learning experience under the guidance of one or more experienced learning facilitators (lecturers or presenters). A major challenge is that the class/conference room is separated from the real world of medical physics. The design of an educational activity needs to take into consideration the desired outcomes with respect to what the learners should be able to do. The distinction is that of being able to apply the knowledge to perform specific physics functions rather than just knowing and being able to recall facts, and perhaps do well on written examinations. These are different types of knowledge structures within the human brain and distinctly different learning activities to develop each. Much of medical physics education, especially at the post-graduate and continuing education level, is for the purpose of enhancing the ability of physicists and other related professionals to perform applied procedures and tasks and requires specific types of knowledge.In this session we will analyze various learning activity models, the values and limitations of each, and how they can be used in medical physics education

  15. Modelling Estimates of Norovirus Disease in Patients with Chronic Medical Conditions

    PubMed Central

    Verstraeten, Thomas; Jiang, Baoguo; Weil, John G.; Lin, Jennifer H.

    2016-01-01

    Background The burden of disease due to norovirus infection has been well described in the general United States population, but studies of norovirus occurrence among persons with chronic medical conditions have been limited mostly to the immunocompromised. We assessed the impact of norovirus gastroenteritis on health care utilization in US subjects with a range of chronic medical conditions. Methods We performed a retrospective cohort study using MarketScan data from July 2002 to December 2013, comparing the rates of emergency department visits, outpatient visits and hospitalizations among patients with chronic conditions (renal, cardiovascular, respiratory, immunocompromising, gastrointestinal, hepatic/pancreatic and neurological conditions and diabetes) with those in a healthy population. We estimated the rates of these outcomes due to norovirus gastroenteritis using an indirect modelling approach whereby cases of gastroenteritis of unknown cause and not attributed to a range of other causes were assumed to be due to norovirus. Results Hospitalization rates for norovirus gastroenteritis were higher in all of the risk groups analyzed compared with data in otherwise healthy subjects, ranging from 3.2 per 10,000 person-years in persons with chronic respiratory conditions, to 23.1 per 10,000 person-years in persons with chronic renal conditions, compared to 2.1 per 10,000 among persons without chronic conditions. Over 51% of all norovirus hospitalizations occurred in the 37% of the population with some form of chronic medical condition. Outpatient visits for norovirus gastroenteritis were also increased in persons with chronic gastrointestinal or immunocompromising conditions. Conclusion Norovirus gastroenteritis leads to significantly higher rates of healthcare utilization in patients with a chronic medical condition compared to patients without any such condition. PMID:27438335

  16. Integrated Medical Model (IMM) Optimization Version 4.0 Functional Improvements

    NASA Technical Reports Server (NTRS)

    Arellano, John; Young, M.; Boley, L.; Garcia, Y.; Saile, L.; Walton, M.; Kerstman, E.; Reyes, D.; Goodenow, D. A.; Myers, J. G.

    2016-01-01

    The IMMs ability to assess mission outcome risk levels relative to available resources provides a unique capability to provide guidance on optimal operational medical kit and vehicle resources. Post-processing optimization allows IMM to optimize essential resources to improve a specific model outcome such as maximization of the Crew Health Index (CHI), or minimization of the probability of evacuation (EVAC) or the loss of crew life (LOCL). Mass and or volume constrain the optimized resource set. The IMMs probabilistic simulation uses input data on one hundred medical conditions to simulate medical events that may occur in spaceflight, the resources required to treat those events, and the resulting impact to the mission based on specific crew and mission characteristics. Because IMM version 4.0 provides for partial treatment for medical events, IMM Optimization 4.0 scores resources at the individual resource unit increment level as opposed to the full condition-specific treatment set level, as done in version 3.0. This allows the inclusion of as many resources as possible in the event that an entire set of resources called out for treatment cannot satisfy the constraints. IMM Optimization version 4.0 adds capabilities that increase efficiency by creating multiple resource sets based on differing constraints and priorities, CHI, EVAC, or LOCL. It also provides sets of resources that improve mission-related IMM v4.0 outputs with improved performance compared to the prior optimization. The new optimization represents much improved fidelity that will improve the utility of the IMM 4.0 for decision support.

  17. Future Directions in Medical Physics: Models, Technology, and Translation to Medicine

    NASA Astrophysics Data System (ADS)

    Siewerdsen, Jeffrey

    The application of physics in medicine has been integral to major advances in diagnostic and therapeutic medicine. Two primary areas represent the mainstay of medical physics research in the last century: in radiation therapy, physicists have propelled advances in conformal radiation treatment and high-precision image guidance; and in diagnostic imaging, physicists have advanced an arsenal of multi-modality imaging that includes CT, MRI, ultrasound, and PET as indispensible tools for noninvasive screening, diagnosis, and assessment of treatment response. In addition to their role in building such technologically rich fields of medicine, physicists have also become integral to daily clinical practice in these areas. The future suggests new opportunities for multi-disciplinary research bridging physics, biology, engineering, and computer science, and collaboration in medical physics carries a strong capacity for identification of significant clinical needs, access to clinical data, and translation of technologies to clinical studies. In radiation therapy, for example, the extraction of knowledge from large datasets on treatment delivery, image-based phenotypes, genomic profile, and treatment outcome will require innovation in computational modeling and connection with medical physics for the curation of large datasets. Similarly in imaging physics, the demand for new imaging technology capable of measuring physical and biological processes over orders of magnitude in scale (from molecules to whole organ systems) and exploiting new contrast mechanisms for greater sensitivity to molecular agents and subtle functional / morphological change will benefit from multi-disciplinary collaboration in physics, biology, and engineering. Also in surgery and interventional radiology, where needs for increased precision and patient safety meet constraints in cost and workflow, development of new technologies for imaging, image registration, and robotic assistance can leverage

  18. Extensions to the time-oriented database model to support temporal reasoning in medical expert systems.

    PubMed

    Kahn, M G; Fagan, L M; Tu, S

    1991-01-01

    Physicians faced with diagnostic and therapeutic decisions must reason about clinical features that change over time. Database-management systems (DBMS) can increase access to patient data, but most systems are limited in their ability to store and retrieve complex temporal information. The Time-Oriented Databank (TOD) model, the most widely used data model for medical database systems, associates a single time stamp with each observation. The proper analysis of most clinical data requires accounting for multiple concurrent clinical events that may alter the interpretation of the raw data. Most medical DBMSs cannot retrieve patient data indexed by multiple clinical events. We describe two logical extensions to TOD-based databases that solve a set of temporal reasoning problems we encountered in constructing medical expert systems. A key feature of both extensions is that stored data are partitioned into groupings, such as sequential clinical visits, clinical exacerbations, or other abstract events that have clinical decision-making relevance. The temporal network (TNET) is an object-oriented database that extends the temporal reasoning capabilities of ONCOCIN, a medical expert system that provides chemotherapy advice. TNET uses persistent objects to associate observations with intervals of time during which "an event of clinical interest" occurred. A second object-oriented system called the extended temporal network (ETNET), is both an extension and a simplification of TNET. Like TNET, ETNET uses persistent objects to represent relevant intervals; unlike the first system, however, ETNET contains reasoning methods (rules) that can be executed when an event "begins", and that are withdrawn when that event "concludes". TNET and ETNET capture temporal relationships among recorded information that are not represented in TOD-based databases. Although they do not solve all temporal reasoning problems found in medical decision making, these new structures enable patient

  19. Developing a multivariate electronic medical record integration model for primary health care.

    PubMed

    Lau, Francis; Price, Morgan; Lesperance, Mary

    2013-01-01

    This paper describes the development of a multivariate electronic medical record (EMR) integration model for the primary health care setting. Our working hypothesis is that an integrated EMR is associated with high quality primary health care. Our assumption is that EMR integration should be viewed as a form of complex intervention with multiple interacting components that can impact the quality of care. Depending on how well the EMR is integrated in the practice setting, one can expect a corresponding change in the quality of care as measured through a set of primary health care quality indicators. To test the face validity of this model, a Delphi study is being planned where health care providers and information technology professionals involved with EMR adoption are polled for their feedback. This model has the potential to quantify and explain the factors that influence successful EMR integration to improve primary health care. PMID:23388317

  20. Modeling and Encoding Clinical Causal Relationships in a Medical Knowledge Base

    PubMed Central

    Blum, Robert L.

    1983-01-01

    This paper presents a method for the computer modeling and encoding of clinical causal relationships (CR's). This method draws on the theory of multivariate linear models and path analysis. The representation was used to encode medical CR's derived empirically from a clinical database by the RX computer project described in SCAMC82. The emphasis in the representation is on capturing the intensities of effects and the variation in the effects across a patient population. This information is used by RX in determining the validity of other CR's. The representation uses a directed graph formalism in which the nodes are frames and the arcs contain seven descriptive features of individual CR's: intensity, distribution, direction, mathematical form, setting, validity, and evidence. Because natural systems (such as the human body) are inherently probabilistic, linear models are useful in representing causal flow in them.

  1. Migration of plasticizers from PVC medical devices: Development of an infusion model.

    PubMed

    Bernard, L; Cueff, R; Chagnon, Mc; Abdoulouhab, F; Décaudin, B; Breysse, C; Kauffmann, S; Cosserant, B; Souweine, B; Sautou, V

    2015-10-15

    Alternatives to DEHP plasticizers are used in various PVC medical devices (MD) for infusion. As they are able to migrate from these MDs into infused solutions, they may come into contact with patient. Different and specific clinical parameters influence their migration in at-risk situations such as infusion. In contrast to the regulations for Food Contact Materials (MCDA), there is currently no acceptable migration limits for the use of these plasticizers in clinical situations. In order to assess their migration, and thus control the risks linked to these MDs, we developed a migration model for the plasticizers in MDs. To this end, we applied a cross-disciplinary methodological process similar to that used in the food-processing industry, taking into account the MDs' conditions of use in clinical practice. The simulation model is simple and includes the following conditions: MD should be tested with a dynamic method that respects our established clinical assumption (2 L of infused solutions via 13 dm(2) of plasticized PVC), at a temperature of 25 °C and during 24 h of contact, using a 50/50 (v/v) ethanol/water simulant. This model could be proposed as a tool for the safety evaluation of the patients' exposure risk to plasticizers from PVC medical devices for infusions. PMID:26278488

  2. Integration of soft tissue model and open haptic device for medical training simulator

    NASA Astrophysics Data System (ADS)

    Akasum, G. F.; Ramdhania, L. N.; Suprijanto; Widyotriatmo, A.

    2016-03-01

    Minimally Invasive Surgery (MIS) has been widely used to perform any surgical procedures nowadays. Currently, MIS has been applied in some cases in Indonesia. Needle insertion is one of simple MIS procedure that can be used for some purposes. Before the needle insertion technique used in the real situation, it essential to train this type of medical student skills. The research has developed an open platform of needle insertion simulator with haptic feedback that providing the medical student a realistic feel encountered during the actual procedures. There are three main steps in build the training simulator, which are configure hardware system, develop a program to create soft tissue model and the integration of hardware and software. For evaluating its performance, haptic simulator was tested by 24 volunteers on a scenario of soft tissue model. Each volunteer must insert the needle on simulator until rearch the target point with visual feedback that visualized on the monitor. From the result it can concluded that the soft tissue model can bring the sensation of touch through the perceived force feedback on haptic actuator by looking at the different force in accordance with different stiffness in each layer.

  3. Nurses and Psychologists Advancing the Patient-Centered Medical Home Model.

    PubMed

    Corso, Kent A; Gage, Donna

    2016-01-01

    As America experiences the largest health care revolution of the past 50 years, clinicians and administrators are refocusing their attention on the goals of the Quadruple Aim. Motivation and capabilities among stakeholders vary as practical tools and an adequate workforce remain elusive. At the same time, the patient-centered medical home (PCMH) model is spreading rapidly but demonstrating variable results. Positive PCMH outcomes seem to reflect high-quality teamwork. A primary care physician shortage is looming, and increasing numbers of health professionals are being pushed into the PCMH, mandated to provide "integrated" care. Even now, the majority of our Graduate Medical Education programs do not train clinicians in team-based workflow models and interaction skills. Consequently, PCMH teams will only optimize and realize the model's true potential if they learn to coordinate, communicate, and collaborate effectively. This means all PCMH staff members achieve solid teamwork skills and work at the top of their license. The authors discuss resources for improving coordination, communication, and collaboration among members of PCMH teams, and strategies for including other professionals. PMID:27259123

  4. Medical image segmentation using minimal path deformable models with implicit shape priors.

    PubMed

    Yan, Pingkun; Kassim, Ashraf A

    2006-10-01

    This paper presents a new method for segmentation of medical images by extracting organ contours, using minimal path deformable models incorporated with statistical shape priors. In our approach, boundaries of structures are considered as minimal paths, i.e., paths associated with the minimal energy, on weighted graphs. Starting from the theory of minimal path deformable models, an intelligent "worm" algorithm is proposed for segmentation, which is used to evaluate the paths and finally find the minimal path. Prior shape knowledge is incorporated into the segmentation process to achieve more robust segmentation. The shape priors are implicitly represented and the estimated shapes of the structures can be conveniently obtained. The worm evolves under the joint influence of the image features, its internal energy, and the shape priors. The contour of the structure is then extracted as the worm trail. The proposed segmentation framework overcomes the short-comings of existing deformable models and has been successfully applied to segmenting various medical images. PMID:17044401

  5. Medical anthropology and Ebola in Congo: cultural models and humanistic care.

    PubMed

    Hewlett, B S; Epelboin, A; Hewlett, B L; Formenty, P

    2005-09-01

    Seldom have medical anthropologists been involved in efforts to control high mortality diseases such as Ebola hemorrhagic fever (EHF) This paper describes the results of two distinct but complementary interventions during the first phases of an outbreak in the Republic of Congo in 2003. The first approach emphasized understanding local peoples cultural models and political-economic explanations for the disease while the second approach focused on providing more humanitarian care of patients by identifying and incorporating local beliefs and practices into patient care and response efforts. PMID:16267966

  6. Development of Antipsychotic Medications with Novel Mechanisms of Action Based on Computational Modeling of Hippocampal Neuropathology

    PubMed Central

    Siekmeier, Peter J.; vanMaanen, David P.

    2013-01-01

    A large number of cellular level abnormalities have been identified in the hippocampus of schizophrenic subjects. Nonetheless, it remains uncertain how these pathologies interact at a system level to create clinical symptoms, and this has hindered the development of more effective antipsychotic medications. Using a 72-processor supercomputer, we created a tissue level hippocampal simulation, featuring multicompartmental neuron models with multiple ion channel subtypes and synaptic channels with realistic temporal dynamics. As an index of the schizophrenic phenotype, we used the specific inability of the model to attune to 40 Hz (gamma band) stimulation, a well-characterized abnormality in schizophrenia. We examined several possible combinations of putatively schizophrenogenic cellular lesions by systematically varying model parameters representing NMDA channel function, dendritic spine density, and GABA system integrity, conducting 910 trials in total. Two discrete “clusters” of neuropathological changes were identified. The most robust was characterized by co-occurring modest reductions in NMDA system function (-30%) and dendritic spine density (-30%). Another set of lesions had greater NMDA hypofunction along with low level GABA system dysregulation. To the schizophrenic model, we applied the effects of 1,500 virtual medications, which were implemented by varying five model parameters, independently, in a graded manner; the effects of known drugs were also applied. The simulation accurately distinguished agents that are known to lack clinical efficacy, and identified novel mechanisms (e.g., decrease in AMPA conductance decay time constant, increase in projection strength of calretinin-positive interneurons) and combinations of mechanisms that could re-equilibrate model behavior. These findings shed light on the mechanistic links between schizophrenic neuropathology and the gamma band oscillatory abnormalities observed in the illness. As such, they generate

  7. Complete optical stack modeling for CMOS-based medical x-ray detectors

    NASA Astrophysics Data System (ADS)

    Zyazin, Alexander S.; Peters, Inge M.

    2015-03-01

    We have developed a simulation tool for modeling the performance of CMOS-based medical x-ray detectors, based on the Monte Carlo toolkit GEANT4. Following the Fujita-Lubberts-Swank approach recently reported by Star-Lack et al., we calculate modulation transfer function MTF(f), noise power spectrum NPS(f) and detective quantum efficiency DQE(f) curves. The complete optical stack is modeled, including scintillator, fiber optic plate (FOP), optical adhesive and CMOS image sensor. For critical parts of the stack, detailed models have been developed, taking into account their respective microstructure. This includes two different scintillator types: Gd2O2S:Tb (GOS) and CsI:Tl. The granular structure of the former is modeled using anisotropic Mie scattering. The columnar structure of the latter is introduced into calculations directly, using the parameterization capabilities of GEANT4. The underlying homogeneous CsI layer is also incorporated into the model as well as the optional reflective layer on top of the scintillator screen or the protective polymer top coat. The FOP is modeled as an array of hexagonal bundles of fibers. The simulated CMOS stack consists of layers of Si3N4 and SiO2 on top of a silicon pixel array. The model is validated against measurements of various test detector structures, using different x-ray spectra (RQA5 and RQA-M2), showing good match between calculated and measured MTF(f) and DQE(f) curves.

  8. [Usability first. Model-based approach for the use-oriented risk analysis of medical devices].

    PubMed

    Janß, A; Radermacher, K

    2014-12-01

    Due to increasing automation, the number and complexity of technical components have increased in the medical context (e.g., in the clinic or in the home care sector) in recent years. Besides new effective and efficient therapeutic and diagnostic options, these devices entail a wide range of functions and very complex (often computer-based) user interfaces that may lead to human-induced risk potential. A systematic and early human risk analysis and a usability evaluation allow medical device manufacturers to identify and control risks within the human-machine interaction very efficiently. At the Department of Medical Engineering in the Helmholtz Institute for Biomedical Engineering at the RWTH Aachen University, a formal-analytical methodology and a corresponding software tool for prospective human-risk analysis and model-based usability evaluation has been developed. Based on a twofold approach, user interactive process sequences and their potential impacts on the overall process are identified and the resulting use-related risks are assessed. For this, the tasks are categorized (in system and user tasks) and modeled and temporally related within the framework of a high-level task analysis. Within a subsequent cognitive low-level task analysis, potentially critical parallel process sequences are then tested in order to detect a potential resource overload of the user. The subsequent corresponding human-risk analysis is developed according to a knowledge base (checklist) of taxonomies related to human error. The HiFEM (human-function effect modeling) methodology is universally applicable and can be used for the evaluation of human-computer interfaces as well as for the analysis of purely mechanical control interfaces and simple hand-held instruments (such as a scalpel and implant). In a comparative study, the HiFEM method clearly outperforms the classic FMEA (failure modes and effects analysis) process with regard to effectiveness, efficiency, learnability, and

  9. Constructing a Measure for Longitudinal Medical Achievement Studies by the Rasch Model One-Step Equating.

    ERIC Educational Resources Information Center

    Shen, Linjun

    As part of a longitudinal study of the growth of general medical knowledge among osteopathic medical students, a simple, convenient, and accurate vertical equating method was developed for constructing a scale for medical achievement. It was believed that Parts 1, 2, and 3 of the National Board of Osteopathic Medical Examiners' (NBOME) examination…

  10. 3-dimensional interactive space (3DIS); A new dimension in asset protection

    SciTech Connect

    Veitch, S. ); Veitch, J. ); West, S.J. )

    1991-01-01

    This paper reports on the 3DIS security system which uses standard CCTV cameras to create 3-Dimensional detection zones around valuable assets within protected areas. An intrusion into a zone changes light values and triggers an alarm that is annunciated, while images from multiple cameras are recorded. 3DIS lowers nuisance alarm rates and provides superior automated surveillance capability. Performance is improved over 2-D systems because activity around, above or below the zone does to cause an alarm. Invisible 3-D zones protect assets as small as a pin or as large as a 747 jetliner. Detection zones are created by excising subspaces from the overlapping fields of view of two or more video cameras. Hundred of zones may co-exist, operating simultaneously. Intrusion into any 3-D zone will cause a coincidental change in light values, triggering an alarm specific to that space.

  11. Theory of relativistic Brownian motion: the (1+3) -dimensional case.

    PubMed

    Dunkel, Jörn; Hänggi, Peter

    2005-09-01

    A theory for (1+3) -dimensional relativistic Brownian motion under the influence of external force fields is put forward. Starting out from a set of relativistically covariant, but multiplicative Langevin equations we describe the relativistic stochastic dynamics of a forced Brownian particle. The corresponding Fokker-Planck equations are studied in the laboratory frame coordinates. In particular, the stochastic integration prescription--i.e., the discretization rule dilemma--is elucidated (prepoint discretization rule versus midpoint discretization rule versus postpoint discretization rule). Remarkably, within our relativistic scheme we find that the postpoint rule (or the transport form) yields the only Fokker-Planck dynamics from which the relativistic Maxwell-Boltzmann statistics is recovered as the stationary solution. The relativistic velocity effects become distinctly more pronounced by going from one to three spatial dimensions. Moreover, we present numerical results for the asymptotic mean-square displacement of a free relativistic Brownian particle moving in 1+3 dimensions. PMID:16241514

  12. A 3-Dimensional Cockpit Display with Traffic and Terrain Information for the Small Aircraft Transportation System

    NASA Technical Reports Server (NTRS)

    UijtdeHaag, Maarten; Thomas, Robert; Rankin, James R.

    2004-01-01

    The report discusses the architecture and the flight test results of a 3-Dimensional Cockpit Display of Traffic and terrain Information (3D-CDTI). The presented 3D-CDTI is a perspective display format that combines existing Synthetic Vision System (SVS) research and Automatic Dependent Surveillance-Broadcast (ADS-B) technology to improve the pilot's situational awareness. The goal of the 3D-CDTI is to contribute to the development of new display concepts for NASA's Small Aircraft Transportation System research program. Papers were presented at the PLANS 2002 meeting and the ION-GPS 2002 meeting. The contents of this report are derived from the results discussed in those papers.

  13. PROMALS3D: multiple protein sequence alignment enhanced with evolutionary and 3-dimensional structural information

    PubMed Central

    Pei, Jimin; Grishin, Nick V.

    2015-01-01

    SUMMARY Multiple sequence alignment (MSA) is an essential tool with many applications in bioinformatics and computational biology. Accurate MSA construction for divergent proteins remains a difficult computational task. The constantly increasing protein sequences and structures in public databases could be used to improve alignment quality. PROMALS3D is a tool for protein MSA construction enhanced with additional evolutionary and structural information from database searches. PROMALS3D automatically identifies homologs from sequence and structure databases for input proteins, derives structure-based constraints from alignments of 3-dimensional structures, and combines them with sequence-based constraints of profile-profile alignments in a consistency-based framework to construct high-quality multiple sequence alignments. PROMALS3D output is a consensus alignment enriched with sequence and structural information about input proteins and their homologs. PROMALS3D web server and package are available at http://prodata.swmed.edu/PROMALS3D. PMID:24170408

  14. The program FANS-3D (finite analytic numerical simulation 3-dimensional) and its applications

    NASA Technical Reports Server (NTRS)

    Bravo, Ramiro H.; Chen, Ching-Jen

    1992-01-01

    In this study, the program named FANS-3D (Finite Analytic Numerical Simulation-3 Dimensional) is presented. FANS-3D was designed to solve problems of incompressible fluid flow and combined modes of heat transfer. It solves problems with conduction and convection modes of heat transfer in laminar flow, with provisions for radiation and turbulent flows. It can solve singular or conjugate modes of heat transfer. It also solves problems in natural convection, using the Boussinesq approximation. FANS-3D was designed to solve heat transfer problems inside one, two and three dimensional geometries that can be represented by orthogonal planes in a Cartesian coordinate system. It can solve internal and external flows using appropriate boundary conditions such as symmetric, periodic and user specified.

  15. Evaluation of the 3-Dimensional, Weight-bearing Orientation of the Normal Adult Knee

    PubMed Central

    Nam, Denis; Shah, Ritesh R.; Nunley, Ryan M.; Barrack, Robert L.

    2014-01-01

    The purpose of this study was to use 3-dimensional, weight-bearing images corrected for rotation to establish normative data of limb alignment and joint line orientation in asymptomatic, adult knees. One hundred adults (200 lower extremities) were recruited to receive weight-bearing, simultaneous biplanar imaging of both lower extremities. Multiple radiographic parameters were measured from 3D images, corrected for limb rotation. 70.0% of knees were in neutral, 19.5% in varus, and 10.5% in valgus overall alignment. Only 31 % of knees possessed both a neutral mechanical axis and the absence of joint line obliquity. There was substantial agreement between the 2D and 3D images for overall mechanical alignment (κ=0.77), but only a moderate agreement for joint line obliquity (κ=0.58). A substantial portion of asymptomatic adults possess either a varus or valgus mechanical alignment and joint line obliquity, PMID:24315446

  16. Carbohydrate Cluster Microarrays Fabricated on 3-Dimensional Dendrimeric Platforms for Functional Glycomics Exploration

    PubMed Central

    Zhou, Xichun; Turchi, Craig; Wang, Denong

    2009-01-01

    We reported here a novel, ready-to-use bioarray platform and methodology for construction of sensitive carbohydrate cluster microarrays. This technology utilizes a 3-dimensional (3-D) poly(amidoamine) starburst dendrimer monolayer assembled on glass surface, which is functionalized with terminal aminooxy and hydrazide groups for site-specific coupling of carbohydrates. A wide range of saccharides, including monosaccharides, oligosaccharides and polysaccharides of diverse structures, are applicable for the 3-D bioarray platform without prior chemical derivatization. The process of carbohydrate coupling is effectively accelerated by microwave radiation energy. The carbohydrate concentration required for microarray fabrication is substantially reduced using this technology. Importantly, this bioarray platform presents sugar chains in defined orientation and cluster configurations. It is, thus, uniquely useful for exploration of the structural and conformational diversities of glyco-epitope and their functional properties. PMID:19791771

  17. DIEP Flap Breast Reconstruction Using 3-dimensional Surface Imaging and a Printed Mold.

    PubMed

    Tomita, Koichi; Yano, Kenji; Hata, Yuki; Nishibayashi, Akimitsu; Hosokawa, Ko

    2015-03-01

    Recent advances in 3-dimensional (3D) surface imaging technologies allow for digital quantification of complex breast tissue. We performed 11 unilateral breast reconstructions with deep inferior epigastric artery perforator (DIEP) flaps (5 immediate, 6 delayed) using 3D surface imaging for easier surgery planning and 3D-printed molds for shaping the breast neoparenchyma. A single- or double-pedicle flap was preoperatively planned according to the estimated tissue volume required and estimated total flap volume. The DIEP flap was then intraoperatively shaped with a 3D-printed mold that was based on a horizontally inverted shape of the contralateral breast. Cosmetic outcomes were assessed as satisfactory, as confirmed by the postoperative 3D measurements of bilateral breasts. We believe that DIEP flap reconstruction assisted with 3D surface imaging and a 3D-printed mold is a simple and quick method for rebuilding a symmetric breast. PMID:25878927

  18. DIEP Flap Breast Reconstruction Using 3-dimensional Surface Imaging and a Printed Mold

    PubMed Central

    Yano, Kenji; Hata, Yuki; Nishibayashi, Akimitsu; Hosokawa, Ko

    2015-01-01

    Summary: Recent advances in 3-dimensional (3D) surface imaging technologies allow for digital quantification of complex breast tissue. We performed 11 unilateral breast reconstructions with deep inferior epigastric artery perforator (DIEP) flaps (5 immediate, 6 delayed) using 3D surface imaging for easier surgery planning and 3D-printed molds for shaping the breast neoparenchyma. A single- or double-pedicle flap was preoperatively planned according to the estimated tissue volume required and estimated total flap volume. The DIEP flap was then intraoperatively shaped with a 3D-printed mold that was based on a horizontally inverted shape of the contralateral breast. Cosmetic outcomes were assessed as satisfactory, as confirmed by the postoperative 3D measurements of bilateral breasts. We believe that DIEP flap reconstruction assisted with 3D surface imaging and a 3D-printed mold is a simple and quick method for rebuilding a symmetric breast. PMID:25878927

  19. S2PLOT: a Straightforward Library for Advanced 3-dimensional Scientific Visualisation

    NASA Astrophysics Data System (ADS)

    Barnes, D. G.; Fluke, C. J.

    2008-08-01

    S2PLOT is a user-oriented programming library for generating and exploring 3-dimensional (3-d) scientific plots and diagrams. It provides a lightweight interface---inspired by the simple yet widely-used PGPLOT---to produce hardware-accelerated visualisations of point, line, image and volumetric data. S2PLOT provides C and FORTRAN interfaces, and supports monoscopic, stereoscopic and curved (eg. dome) display devices. PGPLOT-savvy astronomers can usually write their first S2PLOT program in less than ten minutes. In this paper, we introduce the latest S2PLOT version and highlight major new additions to the library, including volume rendering and isosurfacing of astronomical data. We describe a simple extension that enables the embedding of large-area FITS images directly into S2PLOT programs using standard World Coordinate Systems, and we introduce the Python interface to S2PLOT.

  20. Modeling Passing Rates on a Computer-Based Medical Licensing Examination: An Application of Survival Data Analysis

    ERIC Educational Resources Information Center

    de Champlain, Andre F.; Winward, Marcia L.; Dillon, Gerard F.; de Champlain, Judy E.

    2004-01-01

    The purpose of this article was to model United States Medical Licensing Examination (USMLE) Step 2 passing rates using the Cox Proportional Hazards Model, best known for its application in analyzing clinical trial data. The number of months it took to pass the computer-based Step 2 examination was treated as the dependent variable in the model.…

  1. Efficacy of 3-Dimensional plates over Champys miniplates in mandibular anterior fractures

    PubMed Central

    Barde, Dhananjay H; Mudhol, Anupama; Ali, Fareedi Mukram; Madan, R S; Kar, Sanjay; Ustaad, Farheen

    2014-01-01

    Background: Mandibular fractures are treated surgically by either rigid or semi-rigid fixation, two techniques that reflect almost opposite concept of craniomaxillofacial osteosynthesis. The shortcomings of these fixations led to the development of 3 dimensional (3D) miniplates. This study was designed with the aim of evaluating the efficiency of 3D miniplate over Champys miniplate in anterior mandibular fractures. Materials & Methods: This study was done in 40 patients with anterior mandibular fractures. Group I consisting of 20 patients in whom 3D plates were used for fixation while in Group II consisting of other 20 patients, 4 holes straight plates were used. The efficacy of 3D miniplate over Champy’s miniplate was evaluated in terms of operating time, average pain, post operative infection, occlusion, wound dehiscence, post operative mobility and neurological deficit. Results: The mean operation time for Group II was more compared to Group I (statistically significant).There was significantly greater pain on day of surgery and at 2nd week for Group II patients but there was no significant difference between the two groups at 4th week. The post operative infection, occlusal disturbance, wound dehiscence, post operative mobility at facture site, neurological deficit was statistically insignificant (chi square test). Conclusion: The results of this study suggest that fixation of anterior mandibular fractures with 3D plates provides three dimensional stability and carries low morbidity and infection rates. The only probable limitation of these 3D plates may be excessive implant material, but they seem to be easy alternative to champys miniplate. How to cite the article: Barde DH, Mudhol A, Ali FM, Madan RS, Kar S, Ustaad F. Efficacy of 3-Dimensional plates over Champys miniplates in mandibular anterior fractures. J Int Oral Health 2014;6(1):20-6. PMID:24653598

  2. Selection of massive bone allografts using shape-matching 3-dimensional registration

    PubMed Central

    Docquier, Pierre-Louis; Cartiaux, Olivier; Cornu, Olivier; Delloye, Christian; Banse, Xavier

    2010-01-01

    Background and purpose Massive bone allografts are used when surgery causes large segmental defects. Shape-matching is the primary criterion for selection of an allograft. The current selection method, based on 2-dimensional template comparison, is inefficient for 3-dimensional complex bones. We have analyzed a 3-dimensional (3-D) registration method to match the anatomy of the allograft with that of the recipient. Methods 3-D CT-based registration was performed to match the shapes of both bones. We used the registration to align the allograft volume onto the recipient's bone. Hemipelvic allograft selection was tested in 10 virtual recipients with a panel of 10 potential allografts, including one from the recipient himself (trap graft). 4 observers were asked to visually inspect the superposition of allograft over the recipient, to classify the allografts into 4 categories according to the matching of anatomic zones, and to select the 3 best matching allografts. The results obtained using the registration method were compared with those from a previous study on the template method. Results Using the registration method, the observers systematically detected the trap graft. Selections of the 3 best matching allografts performed using registration and template methods were different. Selection of the 3 best matching allografts was improved by the registration method. Finally, reproducibility of the selection was improved when using the registration method. Interpretation 3-D CT registration provides more useful information than the template method but the final decision lies with the surgeon, who should select the optimal allograft according to his or her own preferences and the needs of the recipient. PMID:20175643

  3. A fundamental, national, medical disaster management plan: an education-based model.

    PubMed

    Djalali, Ahmadreza; Hosseinijenab, Vahid; Hasani, Azadeh; Shirmardi, Kianoush; Castrén, Maaret; Ohlén, Gunnar; Panahi, Farzad

    2009-01-01

    During disasters, especially following earthquakes, health systems are expected to play an essential role in reducing mortality and morbidity. The most significant naturally occurring disaster in Iran is earthquakes; they have killed >180,000 people in the last 90 years. According to the current plan in 2007, the disaster management system of Iran is composed of three main work groups: (1) Prevention and risk management, (2) Education, and (3) Operation. This organizational separation has resulted in lack of necessary training programs for experts of specialized organizations, e.g., the Ministry of Health and Medical Education (MOHME).The National Board of MOHME arranged a training program in the field of medical disaster management. A qualified training team was chosen to conduct this program in each collaborating center, based on a predefined schedule. All collaborating centers were asked to recall 5-7 experts from each member university. Working in medical disaster management field for greater than or equal to 2 years was an inclusion criterion. The training programs lasted three days, consisted of all relevant aspects of medical disaster management, and were conducted over a six-month period (November 2007-April 2008). Pre-test and post-tests were used to examine the participants' knowledge regarding disaster management; the mean score on the pretest was 67.1 +/-11.6 and 88.1 +/-6.2, respectively. All participants were asked to hold the same training course for their organizations in order to enhance knowledge of related managers, stakeholders, and workers, and build capacity at the local and provincial levels. The next step was supposed to be developing a comprehensive medical disaster management plan for the entire country. Establishing nine disaster management regional collaborating centers in the health system of Iran has provided an appropriate base for related programs to be rapidly and easily accomplished throughout the country. This tree-shaped model is

  4. A comprehensive model to build improvement capability in a pediatric academic medical center.

    PubMed

    Kaminski, Gerry M; Schoettker, Pamela J; Alessandrini, Evaline A; Luzader, Carolyn; Kotagal, Uma

    2014-01-01

    Cincinnati Children's Hospital Medical Center developed a comprehensive model to build quality improvement (QI) capability to support its goal to transform its delivery system through a series of training courses. Two online modules orient staff to basic concepts and terminology and prepare them to participate more effectively in QI teams. The basic program (Rapid Cycle Improvement Collaborative, RCIC) is focused on developing the capability to use basic QI tools and complete a narrow-scoped project in approximately 120 days. The Intermediate Improvement Science Series (I(2)S(2)) program is a leadership course focusing on improvement skills and developing a broader and deeper understanding of QI in the context of the organization and external environment. The Advanced Improvement Methods (AIM) course and Quality Scholars Program stimulate the use of more sophisticated methods and prepare Cincinnati Children's Hospital Medical Center (CCHMC) and external faculty to undertake QI research. The Advanced Improvement Leadership Systems (AILS) sessions enable interprofessional care delivery system leadership teams to effectively lead a system of care, manage a portfolio of projects, and to deliver on CCHMC's strategic plan. Implementing these programs has shown us that 1) a multilevel curricular approach to building improvement capability is pragmatic and effective, 2) an interprofessional learning environment is critical to shifting mental models, 3) repetition of project experience with coaching and feedback solidifies critical skills, knowledge and behaviors, and 4) focusing first on developing capable interprofessional improvement leaders, versus engaging in broad general QI training across the whole organization, is effective. PMID:24369867

  5. On the ontological assumptions of the medical model of psychiatry: philosophical considerations and pragmatic tasks

    PubMed Central

    2010-01-01

    A common theme in the contemporary medical model of psychiatry is that pathophysiological processes are centrally involved in the explanation, evaluation, and treatment of mental illnesses. Implied in this perspective is that clinical descriptors of these pathophysiological processes are sufficient to distinguish underlying etiologies. Psychiatric classification requires differentiation between what counts as normality (i.e.- order), and what counts as abnormality (i.e.- disorder). The distinction(s) between normality and pathology entail assumptions that are often deeply presupposed, manifesting themselves in statements about what mental disorders are. In this paper, we explicate that realism, naturalism, reductionism, and essentialism are core ontological assumptions of the medical model of psychiatry. We argue that while naturalism, realism, and reductionism can be reconciled with advances in contemporary neuroscience, essentialism - as defined to date - may be conceptually problematic, and we pose an eidetic construct of bio-psychosocial order and disorder based upon complex systems' dynamics. However we also caution against the overuse of any theory, and claim that practical distinctions are important to the establishment of clinical thresholds. We opine that as we move ahead toward both a new edition of the Diagnostic and Statistical Manual, and a proposed Decade of the Mind, the task at hand is to re-visit nosologic and ontologic assumptions pursuant to a re-formulation of diagnostic criteria and practice. PMID:20109176

  6. Words and wards: a model of reflective writing and its uses in medical education.

    PubMed

    Shapiro, Johanna; Kasman, Deborah; Shafer, Audrey

    2006-01-01

    Personal, creative writing as a process for reflection on patient care and socialization into medicine ("reflective writing") has important potential uses in educating medical students and residents. Based on the authors' experiences with a range of writing activities in academic medical settings, this article sets forth a conceptual model for considering the processes and effects of such writing. The first phase (writing) is individual and solitary, consisting of personal reflection and creation. Here, introspection and imagination guide learners from loss of certainty to reclaiming a personal voice; identifying the patient's voice; acknowledging simultaneously valid yet often conflicting perspectives; and recognizing and responding to the range of emotions triggered in patient care. The next phase (small-group reading and discussion) is public and communal, where sharing one's writing results in acknowledging vulnerability, risk-taking, and self-disclosure. Listening to others' writing becomes an exercise in mindfulness and presence, including witnessing suffering and confusion experienced by others. Specific pedagogical goals in three arenas-professional development, patient care and practitioner well-being - are linked to the writing/reading/listening process. The intent of presenting this model is to help frame future intellectual inquiry and investigation into this innovative pedagogical modality. PMID:17001529

  7. A new model for graduate education and innovation in medical technology.

    PubMed

    Yazdi, Youseph; Acharya, Soumyadipta

    2013-09-01

    We describe a new model of graduate education in bioengineering innovation and design- a year long Master's degree program that educates engineers in the process of healthcare technology innovation for both advanced and low-resource global markets. Students are trained in an iterative "Spiral Innovation" approach that ensures early, staged, and repeated examination of all key elements of a successful medical device. This includes clinical immersion based problem identification and assessment (at Johns Hopkins Medicine and abroad), team based concept and business model development, and project planning based on iterative technical and business plan de-risking. The experiential, project based learning process is closely supported by several core courses in business, design, and engineering. Students in the program work on two team based projects, one focused on addressing healthcare needs in advanced markets and a second focused on low-resource settings. The program recently completed its fourth year of existence, and has graduated 61 students, who have continued on to industry or startups (one half), additional graduate education, or medical school (one third), or our own Global Health Innovation Fellowships. Over the 4 years, the program has sponsored 10 global health teams and 14 domestic/advanced market medtech teams, and launched 5 startups, of which 4 are still active. Projects have attracted over US$2.5M in follow-on awards and grants, that are supporting the continued development of over a dozen projects. PMID:23943068

  8. An ontological modeling approach for abnormal states and its application in the medical domain

    PubMed Central

    2014-01-01

    Background Recently, exchanging data and information has become a significant challenge in medicine. Such data include abnormal states. Establishing a unified representation framework of abnormal states can be a difficult task because of the diverse and heterogeneous nature of these states. Furthermore, in the definition of diseases found in several textbooks or dictionaries, abnormal states are not directly associated with the corresponding quantitative values of clinical test data, making the processing of such data by computers difficult. Results We focused on abnormal states in the definition of diseases and proposed a unified form to describe an abnormal state as a “property,” which can be decomposed into an “attribute” and a “value” in a qualitative representation. We have developed a three-layer ontological model of abnormal states from the generic to disease-specific level. By developing an is-a hierarchy and combining causal chains of diseases, 21,000 abnormal states from 6000 diseases have been captured as generic causal relations and commonalities have been found among diseases across 13 medical departments. Conclusions Our results showed that our representation framework promotes interoperability and flexibility of the quantitative raw data, qualitative information, and generic/conceptual knowledge of abnormal states. In addition, the results showed that our ontological model have found commonalities in abnormal states among diseases across 13 medical departments. PMID:24944781

  9. The combined analysis of uncertainty and patient heterogeneity in medical decision models.

    PubMed

    Groot Koerkamp, Bas; Stijnen, Theo; Weinstein, Milton C; Hunink, M G Myriam

    2011-01-01

    The analysis of both patient heterogeneity and parameter uncertainty in decision models is increasingly recommended. In addition, the complexity of current medical decision models commonly requires simulating individual subjects, which introduces stochastic uncertainty. The combined analysis of uncertainty and heterogeneity often involves complex nested Monte Carlo simulations to obtain the model outcomes of interest. In this article, the authors distinguish eight model types, each dealing with a different combination of patient heterogeneity, parameter uncertainty, and stochastic uncertainty. The analyses that are required to obtain the model outcomes are expressed in equations, explained in stepwise algorithms, and demonstrated in examples. Patient heterogeneity is represented by frequency distributions and analyzed with Monte Carlo simulation. Parameter uncertainty is represented by probability distributions and analyzed with 2nd-order Monte Carlo simulation (aka probabilistic sensitivity analysis). Stochastic uncertainty is analyzed with 1st-order Monte Carlo simulation (i.e., trials or random walks). This article can be used as a reference for analyzing complex models with more than one type of uncertainty and patient heterogeneity. PMID:20974904

  10. Modeling drug exposure data in electronic medical records: an application to warfarin.

    PubMed

    Liu, Mei; Jiang, Min; Kawai, Vivian K; Stein, Charles M; Roden, Dan M; Denny, Joshua C; Xu, Hua

    2011-01-01

    Identification of patients' drug exposure information is critical to drug-related research that is based on electronic medical records (EMRs). Drug information is often embedded in clinical narratives and drug regimens change frequently because of various reasons like intolerance or insurance issues, making accurate modeling challenging. Here, we developed an informatics framework to determine patient drug exposure histories from EMRs by combining natural language processing (NLP) and machine learning (ML) technologies. Our framework consists of three phases: 1) drug entity recognition - identifying drug mentions; 2) drug event detection - labeling drug mentions with a status (e.g., "on" or "stop"); and 3) drug exposure modeling - predicting if a patient is taking a drug at a given time using the status and temporal information associated with the mentions. We applied the framework to determine patient warfarin exposure at hospital admissions and achieved 87% precision, 79% recall, and an area under the receiver-operator characteristic curve of 0.93. PMID:22195139

  11. Potential applications of latent variable modeling for the psychometrics of medical simulation.

    PubMed

    Cai, Li

    2013-10-01

    Use of simulation-based assessments and training has become increasingly widespread in medicine. It is recognized that simulations can yield a wealth of real-time information about the trainee or examinee's performance, from which inferences about proficiency can potentially be drawn. However, for the inferences to be useful, psychometric evaluation should be conducted and validity evidence amassed. Traditionally, educational and psychological measurement has relied on psychometric models that are static, unidimensional, and based on observed scores. In this article, it is argued that modern psychometric models that are dynamic, multidimensional, and based on latent variables may be useful for evaluating medical simulations. It is also argued that modern computational methods based on Bayesian statistics may provide the technical foundation. Several examples are given and issues for further research are discussed. PMID:24084312

  12. Performance of the libraries in Isfahan University of Medical Sciences based on the EFQM model

    PubMed Central

    Karimi, Saeid; Atashpour, Bahareh; Papi, Ahmad; Nouri, Rasul; Hasanzade, Akbar

    2014-01-01

    Introduction: Performance measurement is inevitable for university libraries. Hence, planning and establishing a constant and up-to-date measurement system is required for the libraries, especially the university libraries. The primary studies and analyses reveal that the EFQM Excellence Model has been efficient, and the administrative reform program has focused on the implementation of this model. Therefore, on the basis of these facts as well as the need for a measurement system, the researchers measured the performance of libraries in schools and hospitals supported by Isfahan University of Medical Sciences, using the EFQM Organizational Excellence Model. Materials and Methods: This descriptive research study was carried out by a cross-sectional survey method in 2011. This research study included librarians and library directors of Isfahan University of Medical Sciences (70 people). The validity of the instrument was measured by the specialists in the field of Management and Library Science. To measure the reliability of the questionnaire, the Cronbach's alpha coefficient value was measured (0.93). The t-test, ANOVA, and Spearman's rank correlation coefficient were used for measurements. The data were analyzed by SPSS. Results: Data analysis revealed that the mean score of the performance measurement for the libraries under study and between nine dimensions the highest score was 65.3% for leadership dimension and the lowest scores were 55.1% for people and 55.1% for society results. Conclusion: In general, using the ninth EFQM model the average level of all dimensions, which is in good agreement with normal values, was assessed. However, compared to other results, the criterion people and society results were poor. It is Recommended by forming the expert committee on criterion people and society results by individuals concerned with the various conferences and training courses to improve the aspects. PMID:25540795

  13. An information model to support user-centered design of medical devices.

    PubMed

    Hagedorn, Thomas J; Krishnamurty, Sundar; Grosse, Ian R

    2016-08-01

    The process of engineering design requires the product development team to balance the needs and limitations of many stakeholders, including those of the user, regulatory organizations, and the designing institution. This is particularly true in medical device design, where additional consideration must be given for a much more complex user-base that can only be accessed on a limited basis. Given this inherent challenge, few projects exist that consider design domain concepts, such as aspects of a detailed design, a detailed view of various stakeholders and their capabilities, along with the user-needs simultaneously. In this paper, we present a novel information model approach that combines a detailed model of design elements with a model of the design itself, customer requirements, and of the capabilities of the customer themselves. The information model is used to facilitate knowledge capture and automated reasoning across domains with a minimal set of rules by adopting a terminology that treats customer and design specific factors identically, thus enabling straightforward assessments. A uniqueness of this approach is that it systematically provides an integrated perspective on the key usability information that drive design decisions towards more universal or effective outcomes with the very design information impacted by the usability information. This can lead to cost-efficient optimal designs based on a direct inclusion of the needs of customers alongside those of business, marketing, and engineering requirements. Two case studies are presented to show the method's potential as a more effective knowledge management tool with built-in automated inferences that provide design insight, as well as its overall effectiveness as a platform to develop and execute medical device design from a holistic perspective. PMID:27401857

  14. Self-assembled 3-dimensional arrays of Au@SiO 2 core-shell nanoparticles for enhanced optical nonlinearities

    NASA Astrophysics Data System (ADS)

    Yang, Yong; Hori, Mamiko; Hayakawa, Tomokatsu; Nogami, Masayuki

    2005-04-01

    Homogeneous SiO 2 coated Au nanoparticles were prepared and assembled into densely-packed 3-dimensional arrays by a simple "one-step" route based on the layer-by-layer self-assembly (LBL) technique. Every layer of films exhibited densely packed 2-dimensional arrays of Au@SiO 2 composite nanoparticles and the film thickness was controllable through the number of deposition cycles. These multilayer films exhibited high effective packing density of composite nanoparticles (0.57). Those arrays also exhibited enhanced third-order optical nonlinear responses and ultra-fast response times. The third-order nonlinear optical susceptibility of the seven layer arrays was estimated to be 1.7 × 10 -9 esu at 532 nm and the response time was as fast as several picoseconds. The enhancement of the optical nonlinearity was calculated according to the electrostatic approximation by solution of Laplace's equation under the boundary conditions appropriate to the model of core-shell nanoparticles, and mainly attributed to localized electric-field effects.

  15. Adventitial Cells and Perictyes Support Chondrogenesis Through Different Mechanisms in 3-Dimensional Cultures With or Without Nanoscaffolds.

    PubMed

    Zhang, Shu; Ba, Kai; Wu, Ling; Lee, Siyong; Peault, Bruno; Petrigliano, Frank A; McAllister, David R; Adams, John S; Evseenko, Denis; Lin, Yunfeng

    2015-10-01

    In previous studies, mesenchymal stromal cells (MSCs) derived from bone marrow and fat tissues were shown to increase proliferation and matrix production of chondrocytes (CH) in co-culture. The aim of this study was to investigate the roles of pericytes (CD31(neg)CD45(neg)CD146+CD34(neg)) and adventitial cells (CD31(neg)CD45(neg)CD146(neg)CD34+) sub-populations of MSCs in supporting proliferation and matrix deposition of CH. The MSCs were derived from synovial membrane and attaching fat tissue. Then, the pericytes and adventitial cells were sorted from total MSCs and co-cultured with articular CH respectively. In pellet co-culture model, the pericytes showed more prominent effects on glycosaminoglycans (GAGs) production and Collagen II synthesis than the adventitial cells which had stronger effects on promoting CH proliferation. In addition, quantitative polymerase chain reaction (qPCR) was performed to examine the expression of a group of secreted growth factors and co-culture performed on electrospun scaffolds based on Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB4HB), to verify the trophic effects of different MSC sub-populations in 3-Dimensional (3D) environment. In conclusion, it was found that the pericytes and adventitial cells support CH in different ways; the adventitial cells more supporting the proliferation of CH, while pericytes are better in stimulating GAGs and collagen production of CH. PMID:26502642

  16. Modeling and simulation of multi-physics multi-scale transport phenomenain bio-medical applications

    NASA Astrophysics Data System (ADS)

    Kenjereš, Saša

    2014-08-01

    We present a short overview of some of our most recent work that combines the mathematical modeling, advanced computer simulations and state-of-the-art experimental techniques of physical transport phenomena in various bio-medical applications. In the first example, we tackle predictions of complex blood flow patterns in the patient-specific vascular system (carotid artery bifurcation) and transfer of the so-called "bad" cholesterol (low-density lipoprotein, LDL) within the multi-layered artery wall. This two-way coupling between the blood flow and corresponding mass transfer of LDL within the artery wall is essential for predictions of regions where atherosclerosis can develop. It is demonstrated that a recently developed mathematical model, which takes into account the complex multi-layer arterial-wall structure, produced LDL profiles within the artery wall in good agreement with in-vivo experiments in rabbits, and it can be used for predictions of locations where the initial stage of development of atherosclerosis may take place. The second example includes a combination of pulsating blood flow and medical drug delivery and deposition controlled by external magnetic field gradients in the patient specific carotid artery bifurcation. The results of numerical simulations are compared with own PIV (Particle Image Velocimetry) and MRI (Magnetic Resonance Imaging) in the PDMS (silicon-based organic polymer) phantom. A very good agreement between simulations and experiments is obtained for different stages of the pulsating cycle. Application of the magnetic drug targeting resulted in an increase of up to ten fold in the efficiency of local deposition of the medical drug at desired locations. Finally, the LES (Large Eddy Simulation) of the aerosol distribution within the human respiratory system that includes up to eight bronchial generations is performed. A very good agreement between simulations and MRV (Magnetic Resonance Velocimetry) measurements is obtained

  17. Treatment Outcomes From a Specialist Model for Treating Tobacco Use Disorder in a Medical Center

    PubMed Central

    Burke, Michael V.; Ebbert, Jon O.; Schroeder, Darrell R.; McFadden, David D.; Hays, J. Taylor

    2015-01-01

    Abstract Cigarette smoking causes premature mortality and multiple morbidity; stop smoking improves health. Higher rates of smoking cessation can be achieved through more intensive treatment, consisting of medication and extended counseling of patients, but there are challenges to integrating these interventions into healthcare delivery systems. A care model using a master-level counselor trained as a tobacco treatment specialist (TTS) to deliver behavioral intervention, teamed with a supervising physician/prescriber, affords an opportunity to integrate more intensive tobacco dependence treatment into hospitals, clinics, and other medical systems. This article analyzes treatment outcomes and predictors of abstinence for cigarette smokers being treated using the TTS-physician team in a large outpatient clinic over a 7-year period. This is an observational study of a large cohort of cigarette smokers treated for tobacco dependence at a medical center. Patients referred by the primary healthcare team for a TTS consult received a standard assessment and personalized treatment planning guided by a workbook. Medication and behavioral plans were developed collaboratively with each patient. Six months after the initial assessment, a telephone call was made to ascertain a 7-day period of self-reported abstinence. The univariate association of each baseline patient characteristic with self-reported tobacco abstinence at 6 months was evaluated using the chi-squared test. In addition, a multiple logistic regression analysis was performed with self-reported tobacco abstinence as the dependent variable and all baseline characteristics included as explanatory variables. Over a period of 7 years (2005–2011), 6824 cigarette smokers who provided general research authorization were seen for treatment. The 6-month self-reported abstinence rate was 28.1% (95% confidence interval: 27.7–30.1). The patients most likely to report abstinence were less dependent, more motivated to quit

  18. [Exploring the changes of inheritance model of medical knowledge as viewed from the description of physicians in the Song Dynasty].

    PubMed

    Zhang, Haipeng

    2014-11-01

    From the Southern and Northern Dynasties to the beginning of the Northern Song Dynasty, the models of "master and apprentice" and "physician of long family tradition for generations" were the main ways for teaching medical knowledge. With the rapid amassment of medical books in the Song Dynasty, "reading text" became increasingly important and prominent in the inheritance of medical knowledge, which could be seen clearly from the descriptions on physicians in the Song Dynasty. For instance, Hao Yun's medical knowledge was recorded as a model of "master and apprentice" in Hao Yun's Epitaph written by Zhang Xun. However, in Ye Mengde's description, this model was played down, while at the same time, "reading text" was emphasized. Pang Anshi, though coming from a physician family for generations, got rid of some medical knowledge from his own family and turned to the medical knowledge by "reading text". According to Pang Anshi's Epitaph written by Zhang Lei and Fang ji Zhuan (Biography of Technicians) in Song shi (The Song History), Pang Anshi was a typical model of becoming a famous physician by "reading text". In the Epitaph, Pang Anshi's brilliance was stressed, and in the latter, "reading text" was more important and the family tradition was denied. In the description of the Song Dynasty, Chen Zhaoyu's wonderful medical skills was coming from the "practice", and "reading text" was denied right away. What is more, "reading text" was introspected and criticized through Chen Zhaoyu's lip. The different descriptions of the Song Dynasty reflected the change of inheritance model of medical knowledge. PMID:25620356

  19. A stereo matching model observer for stereoscopic viewing of 3D medical images

    NASA Astrophysics Data System (ADS)

    Wen, Gezheng; Markey, Mia K.; Muralidlhar, Gautam S.

    2014-03-01

    Stereoscopic viewing of 3D medical imaging data has the potential to increase the detection of abnormalities. We present a new stereo model observer inspired by the characteristics of stereopsis in human vision. Given a stereo pair of images of an object (i.e., left and right images separated by a small displacement), the model observer rst nds the corresponding points between the two views, and then fuses them together to create a 2D cyclopean view. Assuming that the cyclopean view has extracted most of the 3D information presented in the stereo pair, a channelized Hotelling observer (CHO) can be utilized to make decisions. We conduct a simulation study that attempts to mimic the detection of breast lesions on stereoscopic viewing of breast tomosynthesis projection images. We render voxel datasets that contain random 3D power-law noise to model normal breast tissues with various breast densities. 3D Gaussian signal is added to some of the datasets to model the presence of a breast lesion. By changing the separation angle between the two views, multiple stereo pairs of projection images are generated for each voxel dataset. The performance of the model is evaluated in terms of the accuracy of binary decisions on the presence of the simulated lesions.

  20. Dr. Auzoux's botanical teaching models and medical education at the universities of Glasgow and Aberdeen.

    PubMed

    Olszewski, Margaret Maria

    2011-09-01

    In the 1860s, Dr. Louis Thomas Jérôme Auzoux introduced a set of papier-mâché teaching models intended for use in the botanical classroom. These botanical models quickly made their way into the educational curricula of institutions around the world. Within these institutions, Auzoux's models were principally used to fulfil educational goals, but their incorporation into diverse curricula also suggests they were used to implement agendas beyond botanical instruction. This essay examines the various uses and meanings of Dr. Auzoux's botanical teaching models at the universities of Glasgow and Aberdeen in the nineteenth century. The two main conclusions of this analysis are: (1) investing in prestigious scientific collections was a way for these universities to attract fee-paying students so that better medical accommodation could be provided and (2) models were used to transmit different kinds of botanical knowledge at both universities. The style of botany at the University of Glasgow was offensive and the department there actively embraced and incorporated ideas of the emerging new botany. At Aberdeen, the style of botany was defensive and there was some hesitancy when confronting new botanical ideas. PMID:21802633

  1. Academic medicine amenities unit: developing a model to integrate academic medical care with luxury hotel services.

    PubMed

    Kennedy, David W; Kagan, Sarah H; Abramson, Kelly Brennen; Boberick, Cheryl; Kaiser, Larry R

    2009-02-01

    The interface between established values of academic medicine and the trend toward inpatient amenities units requires close examination. Opinions of such units can be polarized, reflecting traditional reservations about the ethical dilemma of offering exclusive services only to an elite patient group. An amenities unit was developed at the University of Pennsylvania Health System in 2007, using an approach that integrated academic medicine values with the benefits of philanthropy and service excellence to make amenities unit services available to all patients. Given inherent internal political concerns, a broadly based steering committee of academic and hospital leadership was developed. An academically appropriate model was conceived, anchored by four principles: (1) integration of academic values, (2) interdisciplinary senior leadership, (3) service excellence, and (4) recalibrated occupancy expectations based on multiple revenue streams. Foremost is ensuring the same health care is afforded all patients throughout the hospital, thereby overcoming ethical challenges and optimizing teaching experiences. Service excellence frames the service ethic for all staff, and this, in addition to luxury hotel-style amenities, differentiates the style and feel of the unit from others in the hospital. Recalibrated occupancy creates program viability given revenue streams redefined to encompass gifts and patient revenue, including both reimbursement and self-pay. The medical-surgical amenities patient-care unit has enjoyed a successful first year and a growing stream of returning patients and admitting physicians. Implications for other academic medical centers include opportunities to extrapolate service excellence throughout the hospital and to cultivate philanthropy to benefit services throughout the medical center. PMID:19174661

  2. Experimental research of Fuaile medical adhesive for portal vein embolization in white rabbit models

    PubMed Central

    JIANG, TIANPENG; WANG, LIZHOU; LI, XING; SONG, JIE; WU, XIAOPING; AN, TIANZHI; ZHOU, SHI

    2015-01-01

    The aim of the present study was to investigate the feasibility and efficacy of Fuaile medical adhesive for portal vein embolization in the treatment of a rabbit model. This study used 26 white rabbits, 14 of which were selected and assigned into seven groups (n=2) for the preliminary experiment. Fuaile medical adhesive was mixed with lipiodol at different ratios of 1:0, 1:1, 1:2, 1:3, 1:4, 1:5 and 0:1, respectively, and administered via the portal trunk. The remaining 12 white rabbits were randomly divided into two groups (n=6). The evaluation of the results included the degree of adhesion to the vessels, the extent of embolization and the reaction of the rabbit. Hepatic and renal functions were detected prior to and at 1, 7 and 14 days post-embolization, respectively. Angiography, CT scans and pathological examinations were conducted at post-embolization. Histological examinations revealed that the topical swollen lesions were darker. Light microscopy showed embolic agents in the portal venous blood vessels and the formation of a secondary thrombus. Hepatic necrosis appeared surrounding the embolization area. Inflammatory cell infiltration of different degrees occurred in the early stage and inflammatory fibroplasia occurred in the late stage. Alanine aminotransferase and aspartate aminotransferase levels increased at 1 day post-embolization, peaked at 7 days and was in the normal range at 14 days. The levels of blood urea nitrogen and ceruloplasmin were elevated at 1 day post-embolization and lowered to normal at 7 days. Fuaile medical adhesive is an effective, safe and inexpensive agent, used for effectively inducing embolization in the portal trunk, and the first and second branches of rabbit portal veins. The use of Fuaile therefore merits widespread application in clinical practice. PMID:26137115

  3. Restructuring VA ambulatory care and medical education: the PACE model of primary care.

    PubMed

    Cope, D W; Sherman, S; Robbins, A S

    1996-07-01

    The Veterans Health Administration (VHA) Western Region and associated medical schools formulated a set of recommendations for an improved ambulatory health care delivery system during a 1988 strategic planning conference. As a result, the Department of Veterans Affairs (VA) Medical Center in Sepulveda, California, initiated the Pilot (now Primary) Ambulatory Care and Education (PACE) program in 1990 to implement and evaluate a model program. The PACE program represents a significant departure from traditional VA and non-VA academic medical center care, shifting the focus of care from the inpatient to the outpatient setting. From its inception, the PACE program has used an interdisciplinary team approach with three independent global care firms. Each firm is interdisciplinary in composition, with a matrix management structure that expands role function and empowers team members. Emphasis is on managed primary care, stressing a biopsychosocial approach and cost-effective comprehensive care emphasizing prevention and health maintenance. Information management is provided through a network of personal computers that serve as a front end to the VHA Decentralized Hospital Computer Program (DHCP) mainframe. In addition to providing comprehensive and cost-effective care, the PACE program educates trainees in all health care disciplines, conducts research, and disseminates information about important procedures and outcomes. Undergraduate and graduate trainees from 11 health care disciplines rotate through the PACE program to learn an integrated approach to managed ambulatory care delivery. All trainees are involved in a problem-based approach to learning that emphasizes shared training experiences among health care disciplines. This paper describes the transitional phases of the PACE program (strategic planning, reorganization, and quality improvement) that are relevant for other institutions that are shifting to training programs emphasizing primary and ambulatory care

  4. Aligning academic continuing medical education with quality improvement: a model for the 21st century.

    PubMed

    Davis, Nancy L; Davis, David A; Johnson, Nathan M; Grichnik, Katherine L; Headrick, Linda A; Pingleton, Susan K; Bower, Elizabeth; Gibbs, Ronald

    2013-10-01

    The recent health care quality improvement (QI) movement has called for significant changes to the way that health care is delivered and taught in academic medical centers (AMCs). This movement also has affected academic continuing medical education (CME). In January 2011, to better align the CME and QI efforts of AMCs, the Association of American Medical Colleges (AAMC) launched a pilot initiative called Aligning and Educating for Quality (ae4Q). The goal of this pilot was to assist 11 AMCs as they moved to a more integrated model of continuous performance improvement by aligning their quality measurement and improvement with their continuing education endeavors. In this article, the authors describe the development of the ae4Q pilot and the resulting outcomes that have led to ongoing improvements.During the 18-month pilot, AAMC consultants conducted readiness assessments and on-site visits and provided consultation services and Web-based resources based on the AMC's needs. Following these interventions at each site, they then conducted both interviews with participants and postintervention assessment surveys to measure the impact of the pilot. Findings included demonstrated increases in the alignment of CME and QI, a greater use of quality data in CME design and delivery, and a greater use of CME as an intervention for clinical improvement. Two sites also attributed measureable improved clinical outcomes to their participation in the ae4Q pilot. The AAMC has used these findings to create resources and ongoing services to support AMCs as they pursue efforts to align QI and CME. PMID:23969360

  5. Using latent class analysis to model prescription medications in the measurement of falling among a community elderly population

    PubMed Central

    2013-01-01

    Background Falls among the elderly are a major public health concern. Therefore, the possibility of a modeling technique which could better estimate fall probability is both timely and needed. Using biomedical, pharmacological and demographic variables as predictors, latent class analysis (LCA) is demonstrated as a tool for the prediction of falls among community dwelling elderly. Methods Using a retrospective data-set a two-step LCA modeling approach was employed. First, we looked for the optimal number of latent classes for the seven medical indicators, along with the patients’ prescription medication and three covariates (age, gender, and number of medications). Second, the appropriate latent class structure, with the covariates, were modeled on the distal outcome (fall/no fall). The default estimator was maximum likelihood with robust standard errors. The Pearson chi-square, likelihood ratio chi-square, BIC, Lo-Mendell-Rubin Adjusted Likelihood Ratio test and the bootstrap likelihood ratio test were used for model comparisons. Results A review of the model fit indices with covariates shows that a six-class solution was preferred. The predictive probability for latent classes ranged from 84% to 97%. Entropy, a measure of classification accuracy, was good at 90%. Specific prescription medications were found to strongly influence group membership. Conclusions In conclusion the LCA method was effective at finding relevant subgroups within a heterogenous at-risk population for falling. This study demonstrated that LCA offers researchers a valuable tool to model medical data. PMID:23705639

  6. Metrics of medical image quality: task-based model observers vs. image discrimination/perceptual difference models

    NASA Astrophysics Data System (ADS)

    Eckstein, Miguel P.; Zhang, Yani; Pham, Binh T.

    2004-05-01

    There have been two distinct approaches to develop human vision models that can be used to perform automated evaluation and optimization of medical image quality: linear task based model observers vs. perceptual difference/image discrimination models. Although these two approaches are very different there has been little work directly comparing them in their ability to optimize human performance in clinically relevant tasks. We compared the effectiveness of these two types of metrics of image quality to perform automated computer optimization of JPEG 2000 image compression encoder settings using test images that combined real x-ray coronary angiogram backgrounds with simulated filling defects of 184 different size/shapes. A genetic algorithm was used to optimize the JPEG 2000 encoder settings with respect to: a) a particular task based model observer performance (non-prewhitening matched filter with an eye filter, NPWE; b) a particular perceptual difference/image discrimination model error metric (DCTune2.0; NASA Ames Research Center). A subsequent human psychophysical study was conducted to evaluate the effect of the two different optimized compression encoder settings on visual detection of the simulated filling defect in one of four locations (four alternative forced choice; 4 AFC). Results show that optimizing JPEG 2000 encoder settings with respect to both the NPWE performance and DCTune 2.0 perceptual error lead to improved human task performance relative to human performance with the default encoder settings. However, the NPWE-optimization led to much greater human performance improvement than the perceptual difference model optimization.

  7. Abstinence-Conflict Model: Toward an Optimal Animal Model for Screening Medications Promoting Drug Abstinence.

    PubMed

    Peck, J A

    2016-01-01

    Drug addiction is a significant health and societal problem for which there is no highly effective long-term behavioral or pharmacological treatment. A rising concern are the use of illegal opiate drugs such as heroin and the misuse of legally available pain relievers that have led to serious deleterious health effects or even death. Therefore, treatment strategies that prolong opiate abstinence should be the primary focus of opiate treatment. Further, because the factors that support abstinence in humans and laboratory animals are similar, several animal models of abstinence and relapse have been developed. Here, we review a few animal models of abstinence and relapse and evaluate their validity and utility in addressing human behavior that leads to long-term drug abstinence. Then, a novel abstinence "conflict" model that more closely mimics human drug-seeking episodes by incorporating negative consequences for drug seeking (as are typical in humans, eg, incarceration and job loss) and while the drug remains readily available is discussed. Additionally, recent research investigating both cocaine and heroin seeking in rats using the animal conflict model is presented and the implications for heroin treatments are examined. Finally, it is argued that the use of animal abstinence/relapse models that more closely approximate human drug addiction, such as the abstinence-conflict model, could lead to a better understanding of the neurobiological and environmental factors that support long-term drug abstinence. In turn, this will lead to the development of more effective environmental and pharmacotherapeutic interventions to treat opiate addiction and addiction to other drugs of abuse. PMID:27055619

  8. Nonrigid 3D medical image registration and fusion based on deformable models.

    PubMed

    Liu, Peng; Eberhardt, Benjamin; Wybranski, Christian; Ricke, Jens; Lüdemann, Lutz

    2013-01-01

    For coregistration of medical images, rigid methods often fail to provide enough freedom, while reliable elastic methods are available clinically for special applications only. The number of degrees of freedom of elastic models must be reduced for use in the clinical setting to archive a reliable result. We propose a novel geometry-based method of nonrigid 3D medical image registration and fusion. The proposed method uses a 3D surface-based deformable model as guidance. In our twofold approach, the deformable mesh from one of the images is first applied to the boundary of the object to be registered. Thereafter, the non-rigid volume deformation vector field needed for registration and fusion inside of the region of interest (ROI) described by the active surface is inferred from the displacement of the surface mesh points. The method was validated using clinical images of a quasirigid organ (kidney) and of an elastic organ (liver). The reduction in standard deviation of the image intensity difference between reference image and model was used as a measure of performance. Landmarks placed at vessel bifurcations in the liver were used as a gold standard for evaluating registration results for the elastic liver. Our registration method was compared with affine registration using mutual information applied to the quasi-rigid kidney. The new method achieved 15.11% better quality with a high confidence level of 99% for rigid registration. However, when applied to the quasi-elastic liver, the method has an averaged landmark dislocation of 4.32 mm. In contrast, affine registration of extracted livers yields a significantly (P = 0.000001) smaller dislocation of 3.26 mm. In conclusion, our validation shows that the novel approach is applicable in cases where internal deformation is not crucial, but it has limitations in cases where internal displacement must also be taken into account. PMID:23690883

  9. Technologies in the patient-centered medical home: examining the model from an enterprise perspective.

    PubMed

    Hughes, Cortney L; Marshall, Capt Robert; Murphy, Edward; Mun, Seong K

    2011-01-01

    Fee-for-service reimbursement has fragmented the healthcare system. Providers are paid based on the number of services rendered instead of quality, leading to the cost of care rising at a faster rate than its value. One approach to counter this is the Patient-Centered Medical Home (PCMH), a primary care model that emphasizes team-based medicine, a partnership between patients and providers, and expanded access and communication. The transition to PCMH is facilitated by innovative technologies, such as telemedicine for additional services, electronic medical records to document patients' health needs, and online portals for electronic visits and communication between patients and providers. Implementing these technologies involves tremendous investment of funds and time from practices and healthcare organizations. Although PCMH does not require such technologies, they facilitate its success, as care coordination and population management necessitated by the model are difficult to do without. This article argues that there is a paradox in PCMH and technology is at its center. Although PCMH intends to be cost effective by reducing hospital admissions and ER visits through providing better preventative services, it is actually a financial risk due to the very real upfront costs of implementing and sustaining technologies needed to carry out the intent of the PCMH model, which may not be made up immediately, if ever. This article delves into the rationale behind why payers, providers, and patients have adopted PCMH regardless of this risk and in doing so, maps out the roles that innovative technologies play in the conversion to PCMH. PMID:21663447

  10. Tracking a medically important spider: climate change, ecological niche modeling, and the brown recluse (Loxosceles reclusa).

    PubMed

    Saupe, Erin E; Papes, Monica; Selden, Paul A; Vetter, Richard S

    2011-01-01

    Most spiders use venom to paralyze their prey and are commonly feared for their potential to cause injury to humans. In North America, one species in particular, Loxosceles reclusa (brown recluse spider, Sicariidae), causes the majority of necrotic wounds induced by the Araneae. However, its distributional limitations are poorly understood and, as a result, medical professionals routinely misdiagnose brown recluse bites outside endemic areas, confusing putative spider bites for other serious conditions. To address the issue of brown recluse distribution, we employ ecological niche modeling to investigate the present and future distributional potential of this species. We delineate range boundaries and demonstrate that under future climate change scenarios, the spider's distribution may expand northward, invading previously unaffected regions of the USA. At present, the spider's range is centered in the USA, from Kansas east to Kentucky and from southern Iowa south to Louisiana. Newly influenced areas may include parts of Nebraska, Minnesota, Wisconsin, Michigan, South Dakota, Ohio, and Pennsylvania. These results illustrate a potential negative consequence of climate change on humans and will aid medical professionals in proper bite identification/treatment, potentially reducing bite misdiagnoses. PMID:21464985

  11. Tracking a Medically Important Spider: Climate Change, Ecological Niche Modeling, and the Brown Recluse (Loxosceles reclusa)

    PubMed Central

    Saupe, Erin E.; Papes, Monica; Selden, Paul A.; Vetter, Richard S.

    2011-01-01

    Most spiders use venom to paralyze their prey and are commonly feared for their potential to cause injury to humans. In North America, one species in particular, Loxosceles reclusa (brown recluse spider, Sicariidae), causes the majority of necrotic wounds induced by the Araneae. However, its distributional limitations are poorly understood and, as a result, medical professionals routinely misdiagnose brown recluse bites outside endemic areas, confusing putative spider bites for other serious conditions. To address the issue of brown recluse distribution, we employ ecological niche modeling to investigate the present and future distributional potential of this species. We delineate range boundaries and demonstrate that under future climate change scenarios, the spider's distribution may expand northward, invading previously unaffected regions of the USA. At present, the spider's range is centered in the USA, from Kansas east to Kentucky and from southern Iowa south to Louisiana. Newly influenced areas may include parts of Nebraska, Minnesota, Wisconsin, Michigan, South Dakota, Ohio, and Pennsylvania. These results illustrate a potential negative consequence of climate change on humans and will aid medical professionals in proper bite identification/treatment, potentially reducing bite misdiagnoses. PMID:21464985

  12. Medical Waste Disposal Method Selection Based on a Hierarchical Decision Model with Intuitionistic Fuzzy Relations.

    PubMed

    Qian, Wuyong; Wang, Zhou-Jing; Li, Kevin W

    2016-01-01

    Although medical waste usually accounts for a small fraction of urban municipal waste, its proper disposal has been a challenging issue as it often contains infectious, radioactive, or hazardous waste. This article proposes a two-level hierarchical multicriteria decision model to address medical waste disposal method selection (MWDMS), where disposal methods are assessed against different criteria as intuitionistic fuzzy preference relations and criteria weights are furnished as real values. This paper first introduces new operations for a special class of intuitionistic fuzzy values, whose membership and non-membership information is cross ratio based ]0, 1[-values. New score and accuracy functions are defined in order to develop a comparison approach for ]0, 1[-valued intuitionistic fuzzy numbers. A weighted geometric operator is then put forward to aggregate a collection of ]0, 1[-valued intuitionistic fuzzy values. Similar to Saaty's 1-9 scale, this paper proposes a cross-ratio-based bipolar 0.1-0.9 scale to characterize pairwise comparison results. Subsequently, a two-level hierarchical structure is formulated to handle multicriteria decision problems with intuitionistic preference relations. Finally, the proposed decision framework is applied to MWDMS to illustrate its feasibility and effectiveness. PMID:27618082

  13. Application of pattern recognition tools for classifying acute coronary syndrome: an integrated medical modeling

    PubMed Central

    2013-01-01

    Objective The classification of Acute Coronary Syndrome (ACS), using artificial intelligence (AI), has recently drawn the attention of the medical researchers. Using this approach, patients with myocardial infarction can be differentiated from those with unstable angina. The present study aims to develop an integrated model, based on the feature selection and classification, for the automatic classification of ACS. Methods A dataset containing medical records of 809 patients suspected to suffer from ACS was used. For each subject, 266 clinical factors were collected. At first, a feature selection was performed based on interviews with 20 cardiologists; thereby 40 seminal features for classifying ACS were selected. Next, a feature selection algorithm was also applied to detect a subset of the features with the best classification accuracy. As a result, the feature numbers considerably reduced to only seven. Lastly, based on the seven selected features, eight various common pattern recognition tools for classification of ACS were used. Results The performance of the aforementioned classifiers was compared based on their accuracy computed from their confusion matrices. Among these methods, the multi-layer perceptron showed the best performance with the 83.2% accuracy. Conclusion The results reveal that an integrated AI-based feature selection and classification approach is an effective method for the early and accurate classification of ACS and ultimately a timely diagnosis and treatment of this disease. PMID:24044669

  14. Burnout in Medical Residents: A Study Based on the Job Demands-Resources Model

    PubMed Central

    2014-01-01

    Purpose. Burnout is a prolonged response to chronic emotional and interpersonal stressors on the job. The purpose of our cross-sectional study was to estimate the burnout rates among medical residents in the largest Greek hospital in 2012 and identify factors associated with it, based on the job demands-resources model (JD-R). Method. Job demands were examined via a 17-item questionnaire assessing 4 characteristics (emotional demands, intellectual demands, workload, and home-work demands' interface) and job resources were measured via a 14-item questionnaire assessing 4 characteristics (autonomy, opportunities for professional development, support from colleagues, and supervisor's support). The Maslach Burnout Inventory (MBI) was used to measure burnout. Results. Of the 290 eligible residents, 90.7% responded. In total 14.4% of the residents were found to experience burnout. Multiple logistic regression analysis revealed that each increased point in the JD-R questionnaire score regarding home-work interface was associated with an increase in the odds of burnout by 25.5%. Conversely, each increased point for autonomy, opportunities in professional development, and each extra resident per specialist were associated with a decrease in the odds of burnout by 37.1%, 39.4%, and 59.0%, respectively. Conclusions. Burnout among medical residents is associated with home-work interface, autonomy, professional development, and resident to specialist ratio. PMID:25531003

  15. Cost-Effectiveness Analysis of Intensity Modulated Radiation Therapy Versus 3-Dimensional Conformal Radiation Therapy for Anal Cancer

    SciTech Connect

    Hodges, Joseph C.; Beg, Muhammad S.; Das, Prajnan; Meyer, Jeffrey

    2014-07-15

    Purpose: To compare the cost-effectiveness of intensity modulated radiation therapy (IMRT) and 3-dimensional conformal radiation therapy (3D-CRT) for anal cancer and determine disease, patient, and treatment parameters that influence the result. Methods and Materials: A Markov decision model was designed with the various disease states for the base case of a 65-year-old patient with anal cancer treated with either IMRT or 3D-CRT and concurrent chemotherapy. Health states accounting for rates of local failure, colostomy failure, treatment breaks, patient prognosis, acute and late toxicities, and the utility of toxicities were informed by existing literature and analyzed with deterministic and probabilistic sensitivity analysis. Results: In the base case, mean costs and quality-adjusted life expectancy in years (QALY) for IMRT and 3D-CRT were $32,291 (4.81) and $28,444 (4.78), respectively, resulting in an incremental cost-effectiveness ratio of $128,233/QALY for IMRT compared with 3D-CRT. Probabilistic sensitivity analysis found that IMRT was cost-effective in 22%, 47%, and 65% of iterations at willingness-to-pay thresholds of $50,000, $100,000, and $150,000 per QALY, respectively. Conclusions: In our base model, IMRT was a cost-ineffective strategy despite the reduced acute treatment toxicities and their associated costs of management. The model outcome was sensitive to variations in local and colostomy failure rates, as well as patient-reported utilities relating to acute toxicities.

  16. Integrated Medical Model (IMM) Project Verification, Validation, and Credibility (VVandC)

    NASA Technical Reports Server (NTRS)

    Walton, M.; Boley, L.; Keenan, L.; Kerstman, E.; Shah, R.; Young, M.; Saile, L.; Garcia, Y.; Meyers, J.; Reyes, D.

    2015-01-01

    The Integrated Medical Model (IMM) Project supports end user requests by employing the Integrated Medical Evidence Database (iMED) and IMM tools as well as subject matter expertise within the Project. The iMED houses data used by the IMM. The IMM is designed to forecast relative changes for a specified set of crew health and mission success risk metrics by using a probabilistic model based on historical data, cohort data, and subject matter expert opinion. A stochastic approach is taken because deterministic results would not appropriately reflect the uncertainty in the IMM inputs. Once the IMM was conceptualized, a plan was needed to rigorously assess input information, framework and code, and output results of the IMM, and ensure that end user requests and requirements were considered during all stages of model development and implementation, as well as lay the foundation for external review and application. METHODS: In 2008, the Project team developed a comprehensive verification and validation (VV) plan, which specified internal and external review criteria encompassing 1) verification of data and IMM structure to ensure proper implementation of the IMM, 2) several validation techniques to confirm that the simulation capability of the IMM appropriately represents occurrences and consequences of medical conditions during space missions, and 3) credibility processes to develop user confidence in the information derived from the IMM. When the NASA-STD-7009 (7009) [1] was published, the Project team updated their verification, validation, and credibility (VVC) project plan to meet 7009 requirements and include 7009 tools in reporting VVC status of the IMM. Construction of these tools included meeting documentation and evidence requirements sufficient to meet external review success criteria. RESULTS: IMM Project VVC updates are compiled recurrently and include updates to the 7009 Compliance and Credibility matrices. Reporting tools have evolved over the lifetime of

  17. An eclectic model for evaluating web-based continuing medical education courseware systems.

    PubMed

    Curran, V R

    2000-09-01

    World Wide Web and compact disc-read only memory technologies have introduced new prospects for delivering continuing medical education (CME) to rural and remote physicians. However, evidence concerning the effectiveness of these technologies in providing CME, and approaches to their evaluation, is limited. The rationale for this study was to design a model for evaluating the effectiveness of computer-mediated CME courseware. An eclectic, evaluation-planning matrix was designed by selecting various concepts from the literature and was used in planning and developing the evaluation model. The model was field-tested by evaluating a computer-mediated courseware program on dermatological office procedures, and a meta-evaluation was conducted to assess the effectiveness of the evaluation methods and procedures. The findings suggest that the model was useful in collecting data to inform decision making and to improve the instructional product. The field test results revealed that computer-mediated instruction was effective in delivering CME at a distance. PMID:11067194

  18. MiPLAN: a learner-centered model for bedside teaching in today's academic medical centers.

    PubMed

    Stickrath, Chad; Aagaard, Eva; Anderson, Mel

    2013-03-01

    Clinician educators and medical trainees face intense pressure to complete numerous patient care and teaching activities in a limited amount of time. To address the need for effective and efficient teaching methods for use in the inpatient setting, the authors used constructivist learning theory, the principles of adult learning, and their expertise as clinician educators to develop the MiPLAN model for bedside teaching. This three-part model is designed to enable clinical teachers to simultaneously provide care to patients while assessing learners, determining high-yield teaching topics, and providing feedback to learners.The "M" refers to a preparatory meeting between teacher and learners before engaging in patient care or educational activities. During this meeting, team members should become acquainted and the teacher should set goals and clarify expectations. The "i" refers to five behaviors for the teacher to adopt during learners' bedside presentations: introduction, in the moment, inspection, interruptions, and independent thought. "PLAN" is an algorithm to establish priorities for teaching subsequent to a learner's presentation: patient care, learners' questions, attending's agenda, and next steps.The authors suggest that the MiPLAN model can help clinical teachers gain more confidence in their ability to teach at the bedside and increase the frequency and quality of bedside teaching. They propose further research to assess the generalizability of this model to other institutions, settings, and specialties and to evaluate educational and patient outcomes. PMID:23348088

  19. Multiple-source models for electron beams of a medical linear accelerator using BEAMDP computer code

    PubMed Central

    Jabbari, Nasrollah; Barati, Amir Hoshang; Rahmatnezhad, Leili

    2012-01-01

    Aim The aim of this work was to develop multiple-source models for electron beams of the NEPTUN 10PC medical linear accelerator using the BEAMDP computer code. Background One of the most accurate techniques of radiotherapy dose calculation is the Monte Carlo (MC) simulation of radiation transport, which requires detailed information of the beam in the form of a phase-space file. The computing time required to simulate the beam data and obtain phase-space files from a clinical accelerator is significant. Calculation of dose distributions using multiple-source models is an alternative method to phase-space data as direct input to the dose calculation system. Materials and methods Monte Carlo simulation of accelerator head was done in which a record was kept of the particle phase-space regarding the details of the particle history. Multiple-source models were built from the phase-space files of Monte Carlo simulations. These simplified beam models were used to generate Monte Carlo dose calculations and to compare those calculations with phase-space data for electron beams. Results Comparison of the measured and calculated dose distributions using the phase-space files and multiple-source models for three electron beam energies showed that the measured and calculated values match well each other throughout the curves. Conclusion It was found that dose distributions calculated using both the multiple-source models and the phase-space data agree within 1.3%, demonstrating that the models can be used for dosimetry research purposes and dose calculations in radiotherapy. PMID:24377026

  20. Models of care for late-life depression of the medically ill: examples from chronic obstructive pulmonary disease and stroke.

    PubMed

    Avari, Jimmy N; Alexopoulos, George S

    2015-05-01

    Depression worsens most treatment outcomes in medically ill older adults. Chronic medical illnesses weaken and demoralize patients and compromise their ability to adhere to treatments requiring consistency and effort. Acute medical illnesses create a psychosocial storm that finds patients and their ecosystem unprepared. We describe two intervention models that can be used to target and personalize treatment in depressed, chronically, or acutely medically ill older adults. The Personalized Adherence Intervention for Depression and COPD (PID-C) is a model intervention for depressed patients with chronic medical illnesses. It targets patient-specific barriers to treatment engagement and aims to shift the balance in favor of treatment participation. PID-C led to higher remission rates of depression, reduction in depressive symptoms, and reduction in dyspnea-related disability. The addition of problem-solving training enables patients to use resources available to them and hopefully improve their outcomes. Ecosystem-focused therapy (EFT) is a model intervention for depression developing in the context of an acute medical event. It was developed for patients with poststroke depression (PSD) and targets five areas, part of the "psychosocial storm" originating from the patient's sudden disability and the resulting change in the patient's needs and family's life. A preliminary study suggests that EFT is feasible and efficacious in reducing depressive symptoms and signs and disability in PSD. PMID:25028344