WorldWideScience

Sample records for gyri-precise head model

  1. Analytical modelling of soccer heading

    Indian Academy of Sciences (India)

    Heading occur frequently in soccer games and studies have shown that repetitive heading of the soccer ball could result in degeneration of brain cells and lead to mild traumatic brain injury. This study proposes a two degree-of-freedom linear mathematical model to study the impact of the soccer ball on the brain. The model ...

  2. Analytical modelling of soccer heading

    Indian Academy of Sciences (India)

    MS received 11 April 2014; revised 22 September 2014; accepted 14 February 2015. Abstract. Heading occur frequently in soccer games and studies have shown that repetitive heading of the soccer ball could result in degeneration of brain cells and lead to mild traumatic brain injury. This study proposes a two ...

  3. Biomechanical Modeling of the Human Head

    Science.gov (United States)

    2017-10-03

    Experimental Animal Models for Studies on the Mechanisms of Blast- Induced Neurotrauma,” Frontiers in Neurology 3, 30 (2012). 13. R. A. Bauman, G. Ling...modeling, of both humans and animals , has gained momentum for the investigation of traumatic brain injury. These models require both accurate geometric...between model predictions and experimental data. This report details model calibration for all materials identified in models of a human head and

  4. Finite element modelling of helmeted head impact under frontal ...

    Indian Academy of Sciences (India)

    Abstract. Finite element models of the head and helmet were used to study contact forces during frontal impact of the head with a rigid surface. The finite element model of the head consists of skin, skull, cerebro-spinal fluid (CSF), brain, tentorium and falx. The finite element model of the helmet consists of shell and foam.

  5. Finite element modelling of helmeted head impact under frontal ...

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... Finite element models of the head and helmet were used to study contact forces during frontal impact of the head with a rigid surface. The finite element model of the head consists of skin, skull, cerebro-spinal fluid (CSF), brain, tentorium and falx. The finite element model of the helmet consists of shell and ...

  6. Modeling and nonlinear heading control for sailing yachts

    DEFF Research Database (Denmark)

    Xiao, Lin; Jouffroy, Jerome

    2011-01-01

    This paper presents a study on the development and testing of a model-based heading controller for a sailing yacht. Using Fossen's compact notation for marine vehicles, we first describe a nonlinear 4-DOF dynamic model for a sailing yacht, including roll. Starting from this model, we then design ...... a nonlinear heading controller using the integrator backstepping method, which asymptotically stabilizes the system to the heading/yaw dynamics. Additionally, we present a few simulation results to illustrate the behavior of our control designs....

  7. Head Motion Modeling for Human Behavior Analysis in Dyadic Interaction.

    Science.gov (United States)

    Xiao, Bo; Georgiou, Panayiotis; Baucom, Brian; Narayanan, Shrikanth S

    2015-07-13

    This paper presents a computational study of head motion in human interaction, notably of its role in conveying interlocutors' behavioral characteristics. Head motion is physically complex and carries rich information; current modeling approaches based on visual signals, however, are still limited in their ability to adequately capture these important properties. Guided by the methodology of kinesics, we propose a data driven approach to identify typical head motion patterns. The approach follows the steps of first segmenting motion events, then parametrically representing the motion by linear predictive features, and finally generalizing the motion types using Gaussian mixture models. The proposed approach is experimentally validated using video recordings of communication sessions from real couples involved in a couples therapy study. In particular we use the head motion model to classify binarized expert judgments of the interactants' specific behavioral characteristics where entrainment in head motion is hypothesized to play a role: Acceptance, Blame, Positive , and Negative behavior. We achieve accuracies in the range of 60% to 70% for the various experimental settings and conditions. In addition, we describe a measure of motion similarity between the interaction partners based on the proposed model. We show that the relative change of head motion similarity during the interaction significantly correlates with the expert judgments of the interactants' behavioral characteristics. These findings demonstrate the effectiveness of the proposed head motion model, and underscore the promise of analyzing human behavioral characteristics through signal processing methods.

  8. Evaluation of a laboratory model of human head impact biomechanics.

    Science.gov (United States)

    Hernandez, Fidel; Shull, Peter B; Camarillo, David B

    2015-09-18

    This work describes methodology for evaluating laboratory models of head impact biomechanics. Using this methodology, we investigated: how closely does twin-wire drop testing model head rotation in American football impacts? Head rotation is believed to cause mild traumatic brain injury (mTBI) but helmet safety standards only model head translations believed to cause severe TBI. It is unknown whether laboratory head impact models in safety standards, like twin-wire drop testing, reproduce six degree-of-freedom (6DOF) head impact biomechanics that may cause mTBI. We compared 6DOF measurements of 421 American football head impacts to twin-wire drop tests at impact sites and velocities weighted to represent typical field exposure. The highest rotational velocities produced by drop testing were the 74th percentile of non-injury field impacts. For a given translational acceleration level, drop testing underestimated field rotational acceleration by 46% and rotational velocity by 72%. Primary rotational acceleration frequencies were much larger in drop tests (~100 Hz) than field impacts (~10 Hz). Drop testing was physically unable to produce acceleration directions common in field impacts. Initial conditions of a single field impact were highly resolved in stereo high-speed video and reconstructed in a drop test. Reconstruction results reflected aggregate trends of lower amplitude rotational velocity and higher frequency rotational acceleration in drop testing, apparently due to twin-wire constraints and the absence of a neck. These results suggest twin-wire drop testing is limited in modeling head rotation during impact, and motivate continued evaluation of head impact models to ensure helmets are tested under conditions that may cause mTBI. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. MODEL OF VILLAGE HEAD ELECTION ARRANGEMENT IN VILLAGE GOVERNANCE LAW

    Directory of Open Access Journals (Sweden)

    Sekar Anggun Gading Pinilih

    2017-05-01

    Full Text Available This study aims to examine the right model in the arrangement of village head elections after the stipulation of Law No. 6 year 2014 on Village. This research is a normative law research by laws, historical, and conceptual approach. The result shows that a direct and simultaneous election model shall be the solution for the next Village Head Election. Simultaneous election model is designed since it is philosophically considered to make efficiency of the Village Head Elections, in terms of efficiency of budget, time and effort. The principle of this policy is an attempt to create a more equitable simultaneous democratization to minimize the chances of cheating. Since if the elections were not held simultaneously, it would give chance to the outsider to involve. The simultaneous election requires a coherent policy. This coherence will produce an effective synchronization of all types of elections implementation in Indonesia. Keywords: head of village, model, election, arrangement

  10. Using Topic Models to Interpret MEDLINE's Medical Subject Headings

    Science.gov (United States)

    Newman, David; Karimi, Sarvnaz; Cavedon, Lawrence

    We consider the task of interpreting and understanding a taxonomy of classification terms applied to documents in a collection. In particular, we show how unsupervised topic models are useful for interpreting and understanding MeSH, the Medical Subject Headings applied to articles in MEDLINE. We introduce the resampled author model, which captures some of the advantages of both the topic model and the author-topic model. We demonstrate how topic models complement and add to the information conveyed in a traditional listing and description of a subject heading hierarchy.

  11. Modeling transient streaming potentials in falling-head permeameter tests.

    Science.gov (United States)

    Malama, Bwalya; Revil, André

    2014-01-01

    We present transient streaming potential data collected during falling-head permeameter tests performed on samples of two sands with different physical and chemical properties. The objective of the work is to estimate hydraulic conductivity (K) and the electrokinetic coupling coefficient (Cl ) of the sand samples. A semi-empirical model based on the falling-head permeameter flow model and electrokinetic coupling is used to analyze the streaming potential data and to estimate K and Cl . The values of K estimated from head data are used to validate the streaming potential method. Estimates of K from streaming potential data closely match those obtained from the associated head data, with less than 10% deviation. The electrokinetic coupling coefficient was estimated from streaming potential vs. (1) time and (2) head data for both sands. The results indicate that, within limits of experimental error, the values of Cl estimated by the two methods are essentially the same. The results of this work demonstrate that a temporal record of the streaming potential response in falling-head permeameter tests can be used to estimate both K and Cl . They further indicate the potential for using transient streaming potential data as a proxy for hydraulic head in hydrogeology applications. © 2013, National Ground Water Association.

  12. Modeling and nonlinear heading control for sailing yachts

    DEFF Research Database (Denmark)

    Xiao, Lin; Jouffroy, Jerome

    2011-01-01

    This paper presents a study on the development and testing of a model-based heading controller for a sailing yacht. Using Fossen's compact notation for marine vehicles, we first describe a nonlinear 4-DOF dynamic model for a sailing yacht, including roll. Starting from this model, we then design...

  13. Modeling and nonlinear heading control for sailing yachts

    DEFF Research Database (Denmark)

    Xiao, Lin; Jouffroy, Jerome

    2014-01-01

    This paper presents a study on the development and testing of a model-based heading controller for a sailing yacht. Using Fossen’s compact notation for marine vehicles, we first describe a nonlinear four-degree-of-freedom (DOF) dynamic model for a sailing yacht, including roll. Our model also...

  14. Effect of head model on Monte Carlo modeling of spatial sensitivity distribution for functional near-infrared spectroscopy

    Directory of Open Access Journals (Sweden)

    Ting Li

    2015-09-01

    Full Text Available Modeling Light propagation within human head to deduce spatial sensitivity distribution (SSD is important for Near-infrared spectroscopy (NIRS/imaging (NIRI and diffuse correlation tomography. Lots of head models have been used on this issue, including layered head model, artificial simplified head model, MRI slices described head model, and visible human head model. Hereinto, visible Chinese human (VCH head model is considered to be a most faithful presentation of anatomical structure, and has been highlighted to be employed in modeling light propagation. However, it is not practical for all researchers to use VCH head models and actually increasing number of people are using magnet resonance imaging (MRI head models. Here, all the above head models were simulated and compared, and we focused on the effect of using different head models on predictions of SSD. Our results were in line with the previous reports on the effect of cerebral cortex folding geometry. Moreover, the influence on SSD increases with the fidelity of head models. And surprisingly, the SSD percentages in scalp and gray matter (region of interest in MRI head model were found to be 80% and 125% higher than in VCH head model. MRI head models induced nonignorable discrepancy in SSD estimation when compared with VCH head model. This study, as we believe, is the first to focus on comparison among full serials of head model on estimating SSD, and provided quantitative evidence for MRI head model users to calibrate their SSD estimation.

  15. Evaluation of a pig femoral head osteonecrosis model

    Science.gov (United States)

    2010-01-01

    Background A major cause of osteonecrosis of the femoral head is interruption of a blood supply to the proximal femur. In order to evaluate blood circulation and pathogenetic alterations, a pig femoral head osteonecrosis model was examined to address whether ligature of the femoral neck (vasculature deprivation) induces a reduction of blood circulation in the femoral head, and whether transphyseal vessels exist for communications between the epiphysis and the metaphysis. We also tested the hypothesis that the vessels surrounding the femoral neck and the ligamentum teres represent the primary source of blood flow to the femoral head. Methods Avascular osteonecrosis of the femoral head was induced in Yorkshire pigs by transecting the ligamentum teres and placing two ligatures around the femoral neck. After heparinized saline infusion and microfil perfusion via the abdominal aorta, blood circulation in the femoral head was evaluated by optical and CT imaging. Results An angiogram of the microfil casted sample allowed identification of the major blood vessels to the proximal femur including the iliac, common femoral, superficial femoral, deep femoral and circumflex arteries. Optical imaging in the femoral neck showed that a microfil stained vessel network was visible in control sections but less noticeable in necrotic sections. CT images showed a lack of microfil staining in the epiphysis. Furthermore, no transphyseal vessels were observed to link the epiphysis to the metaphysis. Conclusion Optical and CT imaging analyses revealed that in this present pig model the ligatures around the femoral neck were the primary cause of induction of avascular osteonecrosis. Since the vessels surrounding the femoral neck are comprised of the branches of the medial and the lateral femoral circumflex vessels, together with the extracapsular arterial ring and the lateral epiphyseal arteries, augmentation of blood circulation in those arteries will improve pathogenetic alterations in

  16. Evaluation of a pig femoral head osteonecrosis model

    Directory of Open Access Journals (Sweden)

    Kim Harry

    2010-03-01

    Full Text Available Abstract Background A major cause of osteonecrosis of the femoral head is interruption of a blood supply to the proximal femur. In order to evaluate blood circulation and pathogenetic alterations, a pig femoral head osteonecrosis model was examined to address whether ligature of the femoral neck (vasculature deprivation induces a reduction of blood circulation in the femoral head, and whether transphyseal vessels exist for communications between the epiphysis and the metaphysis. We also tested the hypothesis that the vessels surrounding the femoral neck and the ligamentum teres represent the primary source of blood flow to the femoral head. Methods Avascular osteonecrosis of the femoral head was induced in Yorkshire pigs by transecting the ligamentum teres and placing two ligatures around the femoral neck. After heparinized saline infusion and microfil perfusion via the abdominal aorta, blood circulation in the femoral head was evaluated by optical and CT imaging. Results An angiogram of the microfil casted sample allowed identification of the major blood vessels to the proximal femur including the iliac, common femoral, superficial femoral, deep femoral and circumflex arteries. Optical imaging in the femoral neck showed that a microfil stained vessel network was visible in control sections but less noticeable in necrotic sections. CT images showed a lack of microfil staining in the epiphysis. Furthermore, no transphyseal vessels were observed to link the epiphysis to the metaphysis. Conclusion Optical and CT imaging analyses revealed that in this present pig model the ligatures around the femoral neck were the primary cause of induction of avascular osteonecrosis. Since the vessels surrounding the femoral neck are comprised of the branches of the medial and the lateral femoral circumflex vessels, together with the extracapsular arterial ring and the lateral epiphyseal arteries, augmentation of blood circulation in those arteries will improve

  17. Model-Based Real-Time Head Tracking

    Directory of Open Access Journals (Sweden)

    Ström Jacob

    2002-01-01

    Full Text Available This paper treats real-time tracking of a human head using an analysis by synthesis approach. The work is based on the Structure from Motion (SfM algorithm from Azarbayejani and Pentland (1995. We will analyze the convergence properties of the SfM algorithm for planar objects, and extend it to handle new points. The extended algorithm is then used for head tracking. The system tracks feature points in the image using a texture mapped three-dimensional model of the head. The texture is updated adaptively so that points in the ear region can be tracked when the user′s head is rotated far, allowing out-of-plane rotation of up to without losing track. The covariance of the - and the -coordinates are estimated and forwarded to the Kalman filter, making the tracker robust to occlusion. The system automatically detects tracking failure and reinitializes the algorithm using information gathered in the original initialization process.

  18. Ranking Medical Subject Headings using a factor graph model.

    Science.gov (United States)

    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.

  19. Animation of 3D Model of Human Head

    Directory of Open Access Journals (Sweden)

    V. Michalcin

    2007-04-01

    Full Text Available The paper deals with the new algorithm of animation of 3D model of the human head in combination with its global motion. The designed algorithm is very fast and with low calculation requirements, because it does not need the synthesis of the input videosequence for estimation of the animation parameters as well as the parameters of global motion. The used 3D model Candide generates different expressions using its animation units which are controlled by the animation parameters. These ones are estimated on the basis of optical flow without the need of extracting of the feature points in the frames of the input videosequence because they are given by the selected vertices of the animation units of the calibrated 3D model Candide. The established multiple iterations inside the designed animation algorithm of 3D model of the human head between two successive frames significantly improved its accuracy above all for the large motion.

  20. Corrected Four-Sphere Head Model for EEG Signals

    Directory of Open Access Journals (Sweden)

    Solveig Næss

    2017-10-01

    Full Text Available The EEG signal is generated by electrical brain cell activity, often described in terms of current dipoles. By applying EEG forward models we can compute the contribution from such dipoles to the electrical potential recorded by EEG electrodes. Forward models are key both for generating understanding and intuition about the neural origin of EEG signals as well as inverse modeling, i.e., the estimation of the underlying dipole sources from recorded EEG signals. Different models of varying complexity and biological detail are used in the field. One such analytical model is the four-sphere model which assumes a four-layered spherical head where the layers represent brain tissue, cerebrospinal fluid (CSF, skull, and scalp, respectively. While conceptually clear, the mathematical expression for the electric potentials in the four-sphere model is cumbersome, and we observed that the formulas presented in the literature contain errors. Here, we derive and present the correct analytical formulas with a detailed derivation. A useful application of the analytical four-sphere model is that it can serve as ground truth to test the accuracy of numerical schemes such as the Finite Element Method (FEM. We performed FEM simulations of the four-sphere head model and showed that they were consistent with the corrected analytical formulas. For future reference we provide scripts for computing EEG potentials with the four-sphere model, both by means of the correct analytical formulas and numerical FEM simulations.

  1. Development of a Finite Element Head Model for the Study of Impact Head Injury

    Directory of Open Access Journals (Sweden)

    Bin Yang

    2014-01-01

    Full Text Available This study is aimed at developing a high quality, validated finite element (FE human head model for traumatic brain injuries (TBI prediction and prevention during vehicle collisions. The geometry of the FE model was based on computed tomography (CT and magnetic resonance imaging (MRI scans of a volunteer close to the anthropometry of a 50th percentile male. The material and structural properties were selected based on a synthesis of current knowledge of the constitutive models for each tissue. The cerebrospinal fluid (CSF was simulated explicitly as a hydrostatic fluid by using a surface-based fluid modeling method. The model was validated in the loading condition observed in frontal impact vehicle collision. These validations include the intracranial pressure (ICP, brain motion, impact force and intracranial acceleration response, maximum von Mises stress in the brain, and maximum principal stress in the skull. Overall results obtained in the validation indicated improved biofidelity relative to previous FE models, and the change in the maximum von Mises in the brain is mainly caused by the improvement of the CSF simulation. The model may be used for improving the current injury criteria of the brain and anthropometric test devices.

  2. Development of a finite element head model for the study of impact head injury.

    Science.gov (United States)

    Yang, Bin; Tse, Kwong-Ming; Chen, Ning; Tan, Long-Bin; Zheng, Qing-Qian; Yang, Hui-Min; Hu, Min; Pan, Gang; Lee, Heow-Pueh

    2014-01-01

    This study is aimed at developing a high quality, validated finite element (FE) human head model for traumatic brain injuries (TBI) prediction and prevention during vehicle collisions. The geometry of the FE model was based on computed tomography (CT) and magnetic resonance imaging (MRI) scans of a volunteer close to the anthropometry of a 50th percentile male. The material and structural properties were selected based on a synthesis of current knowledge of the constitutive models for each tissue. The cerebrospinal fluid (CSF) was simulated explicitly as a hydrostatic fluid by using a surface-based fluid modeling method. The model was validated in the loading condition observed in frontal impact vehicle collision. These validations include the intracranial pressure (ICP), brain motion, impact force and intracranial acceleration response, maximum von Mises stress in the brain, and maximum principal stress in the skull. Overall results obtained in the validation indicated improved biofidelity relative to previous FE models, and the change in the maximum von Mises in the brain is mainly caused by the improvement of the CSF simulation. The model may be used for improving the current injury criteria of the brain and anthropometric test devices.

  3. 3D Dynamic Modeling of the Head-Neck Complex for Fast Eye and Head Orientation Movements Research

    Directory of Open Access Journals (Sweden)

    Daniel A. Sierra

    2011-01-01

    Full Text Available A 3D dynamic computer model for the movement of the head-neck complex is presented. It incorporates anatomically correct information about the diverse elements forming the system. The skeleton is considered as a set of interconnected rigid 3D bodies following the Newton-Euler laws of movement. The muscles are modeled using Enderle's linear model, which shows equivalent dynamic characteristics to Loeb's virtual muscle model. The soft tissues, namely, the ligaments, intervertebral disks, and facet joints, are modeled considering their physiological roles and dynamics. In contrast with other head and neck models developed for safety research, the model is aimed to study the neural control of the complex during fast eye and head movements, such as saccades and gaze shifts. In particular, the time-optimal hypothesis and the feedback control ones are discussed.

  4. Electric field distribution in a finite-volume head model of deep brain stimulation

    OpenAIRE

    Grant, Peadar F.; Lowery, Madeleine M.

    2009-01-01

    This study presents a whole-head finite element model of deep brain stimulation to examine the effect of electrical grounding, the finite conducting volume of the head, and scalp, skull and cerebrospinal fluid layers. The impedance between the stimulating and reference electrodes in the whole-head model was found to lie within clinically reported values when the reference electrode was incorporated on a localized surface in the model. Incorporation of the finite volume of the head and inclusi...

  5. Patient Specific Modeling of Head-Up Tilt

    DEFF Research Database (Denmark)

    Williams, Nakeya; Wright, Andrew; Mehlsen, Jesper

    2014-01-01

    blood pressure. The model contains five compartments representing arteries and veins in the upper and lower body of the systemic circulation, as well as the left ventricle facilitating pumping of the heart. A physiologically based sub-model describes gravitational effects on pooling of blood during......Short term cardiovascular responses to head-up tilt (HUT) experiments involve complex cardiovascular regulation in order to maintain blood pressure at homeostatic levels. This manuscript presents a patient specific compartmental model developed to predict dynamic changes in heart rate and arterial...... that it is possible to estimate a subset of model parameters that allows prediction of observed changes in arterial blood pressure. Furthermore, the model adequately predicts arterial and venous blood pressures, as well as cardiac output in compartments for which data are not available....

  6. MATHEMATICAL MODEL OF TRIAXIAL MULTIMODE ATTITUDE AND HEADING REFERENCE SYSTEM

    Directory of Open Access Journals (Sweden)

    Olha Sushchenko

    2017-07-01

    Full Text Available Purpose: The paper deals with the mathematical description of the gimballed attitude and heading reference systems, which can be applied in design of strategic precision navigation systems. The main goal is to created mathematical description taking into consideration the necessity to use different navigations operating modes of this class of navigation systems. To provide the high accuracy the indirect control is used when the position of the gimballed platform is controlled by signals of gyroscopic devices, which are corrected using accelerometer’s signals. Methods: To solve the given problem the methods of the classical theoretical mechanics, gyro theory, and inertial navigation are used. Results: The full mathematical model of the gimballed attitude and heading reference system is derived including descriptions of different operating modes. The mathematical models of the system Expressions for control and correction moments in the different modes are represented. The simulation results are given. Conclusions: The represented results prove efficiency of the proposed models. Developed mathematical models can be useful for design of navigation systems of the wide class of moving vehicles.

  7. Classification of boar spermatozoid head images using a model intracellular density distribution

    NARCIS (Netherlands)

    Sánchez, Lidia; Petkov, Nicolai; Alegre, Enrique; Sanfeliu, A; Cortes, ML

    2005-01-01

    We propose a novel classification method to identify boar spermatozoid heads which present an intracellular intensity distribution similar to a model. From semen sample images, head images are isolated and normalized. We define a model intensity distribution averaging a set of head images assumed as

  8. Development of Realistic Head Models for Electromagnetic Source Imaging of the Human Brain

    National Research Council Canada - National Science Library

    Akalin, Z

    2001-01-01

    In this work, a methodology is developed to solve the forward problem of electromagnetic source imaging using realistic head models, For this purpose, first segmentation of the 3 dimensional MR head...

  9. Realistic Avatar Eye and Head Animation Using a Neurobiological Model of Visual Attention

    National Research Council Canada - National Science Library

    Itti, L; Dhavale, N; Pighin, F

    2003-01-01

    We describe a neurobiological model of visual attention and eye/head movements in primates, and its application to the automatic animation of a realistic virtual human head watching an unconstrained...

  10. The Effect of Head Model Simplification on Beamformer Source Localization

    Directory of Open Access Journals (Sweden)

    Frank Neugebauer

    2017-11-01

    Full Text Available Beamformers are a widely-used tool in brain analysis with magnetoencephalography (MEG and electroencephalography (EEG. For the construction of the beamformer filters realistic head volume conductor modeling is necessary for accurately computing the EEG and MEG leadfields, i.e., for solving the EEG and MEG forward problem. In this work, we investigate the influence of including realistic head tissue compartments into a finite element method (FEM model on the beamformer's localization ability. Specifically, we investigate the effect of including cerebrospinal fluid, gray matter, and white matter distinction, as well as segmenting the skull bone into compacta and spongiosa, and modeling white matter anisotropy. We simulate an interictal epileptic measurement with white sensor noise. Beamformer filters are constructed with unit gain, unit array gain, and unit noise gain constraint. Beamformer source positions are determined by evaluating power and excess sample kurtosis (g2 of the source-waveforms at all source space nodes. For both modalities, we see a strong effect of modeling the cerebrospinal fluid and white and gray matter. Depending on the source position, both effects can each be in the magnitude of centimeters, rendering their modeling necessary for successful localization. Precise skull modeling mainly effected the EEG up to a few millimeters, while both modalities could profit from modeling white matter anisotropy to a smaller extent of 5–10 mm. The unit noise gain or neural activity index beamformer behaves similarly to the array gain beamformer when noise strength is sufficiently high. Variance localization seems more robust against modeling errors than kurtosis.

  11. Rupture tests with reactor pressure vessel head models

    International Nuclear Information System (INIS)

    Talja, H.; Keinaenen, H.; Hosio, E.; Pankakoski, P.H.; Rahka, K.

    2003-01-01

    In the LISSAC project (LImit Strains in Severe ACcidents), partly funded by the EC Nuclear Fission and Safety Programme within the 5th Framework programme, an extensive experimental and computational research programme is conducted to study the stress state and size dependence of ultimate failure strains. The results are aimed especially to make the assessment of severe accident cases more realistic. For the experiments in the LISSAC project a block of material of the German Biblis C reactor pressure vessel was available. As part of the project, eight reactor pressure vessel head models from this material (22 NiMoCr 3 7) were tested up to rupture at VTT. The specimens were provided by Forschungszentrum Karlsruhe (FzK). These tests were performed under quasistatic pressure load at room temperature. Two specimens sizes were tested and in half of the tests the specimens contain holes describing the control rod penetrations of an actual reactor pressure vessel head. These specimens were equipped with an aluminium liner. All six tests with the smaller specimen size were conducted successfully. In the test with the large specimen with holes, the behaviour of the aluminium liner material proved to differ from those of the smaller ones. As a consequence the experiment ended at the failure of the liner. The specimen without holes yielded results that were in very good agreement with those from the small specimens. (author)

  12. Does Head Start differentially benefit children with risks targeted by the program's service model?

    Science.gov (United States)

    Miller, Elizabeth B; Farkas, George; Duncan, Greg J

    Data from the Head Start Impact Study ( N = 3540) were used to test for differential benefits of Head Start after one program year and after kindergarten on pre-academic and behavior outcomes for children at risk in the domains targeted by the program's comprehensive services. Although random assignment to Head Start produced positive treatment main effects on children's pre-academic skills and behavior problems, residualized growth models showed that random assignment to Head Start did not differentially benefit the pre-academic skills of children with risk factors targeted by the Head Start service model. The models showed detrimental impacts of Head Start for maternal-reported behavior problems of high-risk children, but slightly more positive impacts for teacher-reported behavior. Policy implications for Head Start are discussed.

  13. Peningkatan Hasil Belajar PKn Materi Organisasi melalui Model Numbered Head Together di Kelas V

    Directory of Open Access Journals (Sweden)

    Endah Tri Wahyuni

    2017-11-01

    Full Text Available Penelitian peningkatan hasil belajar pendidikan kewarganegaraan melalui model Numbered Heads Together bertujuan untuk mendeskripsikan penerapan model Numbered Heads Together dalam pendidikan kewarganegaraan dengan materi organisasi dan menggambarkan peningkatan hasil belajar siswa dengan menggunakan model Numbered Heads Together. Ini akan sangat berguna bagi siswa dan guru dalam belajar. Model Numbered Heads Together juga dapat meningkatkan aktivitas guru dan siswa. Penelitian ini merupakan penelitian tindakan kelas. Hasil penelitian menunjukkan (1 Penerapan model pembelajaran Numbered Heads Together pada pembelajaran PKn dilaksanakan guru dengan baik dan sesuai dengan langkah-langkah pembelajaran Numbered Heads Together, (2 siklus I, ketuntasan belajar klasikal mengalami peningkatan sebesar 67% dengan kualifikasi cukup dan pada siklus II ketuntasan klasikal meningkat menjadi 92% dengan kualifikasi sangat baik.

  14. Low resolution brain electromagnetic tomography in a realistic geometry head model: a simulation study

    International Nuclear Information System (INIS)

    Ding Lei; Lai Yuan; He Bin

    2005-01-01

    It is of importance to localize neural sources from scalp recorded EEG. Low resolution brain electromagnetic tomography (LORETA) has received considerable attention for localizing brain electrical sources. However, most such efforts have used spherical head models in representing the head volume conductor. Investigation of the performance of LORETA in a realistic geometry head model, as compared with the spherical model, will provide useful information guiding interpretation of data obtained by using the spherical head model. The performance of LORETA was evaluated by means of computer simulations. The boundary element method was used to solve the forward problem. A three-shell realistic geometry (RG) head model was constructed from MRI scans of a human subject. Dipole source configurations of a single dipole located at different regions of the brain with varying depth were used to assess the performance of LORETA in different regions of the brain. A three-sphere head model was also used to approximate the RG head model, and similar simulations performed, and results compared with the RG-LORETA with reference to the locations of the simulated sources. Multi-source localizations were discussed and examples given in the RG head model. Localization errors employing the spherical LORETA, with reference to the source locations within the realistic geometry head, were about 20-30 mm, for four brain regions evaluated: frontal, parietal, temporal and occipital regions. Localization errors employing the RG head model were about 10 mm over the same four brain regions. The present simulation results suggest that the use of the RG head model reduces the localization error of LORETA, and that the RG head model based LORETA is desirable if high localization accuracy is needed

  15. Penerapan Strategi Numbered Head Together dalam Setting Model Pembelajaran STAD

    Directory of Open Access Journals (Sweden)

    Muhammad Mifta Fausan

    2016-07-01

    Full Text Available This study aims to determine the increase of motivation and biology student learning outcomes through the implementation of Numbered Head Together (NHT strategies in setting Student Teams Achievement Division (STAD learning model based Lesson Study (LS. Subjects in this study were students of class X IS 1 MAN 3 Malang. Implementation this study consisted of two cycles and each cycle consisted of three meetings. The data obtained were analyzed using descriptive statistical analysis of qualitative and quantitative descriptive statistics. The research instrument used is the observation sheet, test, monitoring LS sheets and questionnaires. The results of this study indicate that through the implementation of NHT strategy in setting STAD learning model based LS can improve motivation and learning outcomes biology students. Students' motivation in the first cycle of 69% and increased in the second cycle of 86%. While the cognitive learning, classical completeness in the first cycle of 74% and increased in the second cycle to 93%. Affective learning outcomes of students in the first cycle by 93% and increased in the second cycle to 100%. Furthermore, psychomotor learning outcomes of students also increased from 74% in the first cycle to 93% in the second cycle.

  16. Application of Richards\\'s growth model to Brown-headed Parrot ...

    African Journals Online (AJOL)

    Application of Richards\\'s growth model to Brown-headed Parrot Poicephalus cryptoxanthus nestlings. ... Stuart Taylor, Michael R Perrin. Abstract. We generated a generalised growth curve for the Brown-headed Parrot Poicephalus cryptoxanthus. The growth model correlated well with the data from captive-bred chicks and ...

  17. Head and cervical spine posture in behaving rats: implications for modeling human conditions involving the head and cervical spine.

    Science.gov (United States)

    Griffin, C; Choong, W Y; Teh, W; Buxton, A J; Bolton, P S

    2015-02-01

    The aim of this study was to define the temporal and spatial (postural) characteristics of the head and cervical vertebral column (spine) of behaving rats in order to better understand their suitability as a model to study human conditions involving the head and neck. Time spent in each of four behavioral postures was determined from video tape recordings of rats (n = 10) in the absence and presence of an intruder rat. Plain film radiographic examination of a subset of these rats (n = 5) in each of these postures allowed measurement of head and cervical vertebral column positions adopted by the rats. When single they were quadruped or crouched most (∼80%) of the time and bipedal either supported or free standing for only ∼10% of the time. The introduction of an intruder significantly (P columns but, in contrast to humans, they displace their head in space by movements at both the cervico-thoracic junction and the cranio-cervical regions. © 2014 Wiley Periodicals, Inc.

  18. Simulation Model for Correction and Modeling of Probe Head Errors in Five-Axis Coordinate Systems

    Directory of Open Access Journals (Sweden)

    Adam Gąska

    2016-05-01

    Full Text Available Simulative methods are nowadays frequently used in metrology for the simulation of measurement uncertainty and the prediction of errors that may occur during measurements. In coordinate metrology, such methods are primarily used with the typical three-axis Coordinate Measuring Machines (CMMs, and lately, also with mobile measuring systems. However, no similar simulative models have been developed for five-axis systems in spite of their growing popularity in recent years. This paper presents the numerical model of probe head errors for probe heads that are used in five-axis coordinate systems. The model is based on measurements of material standards (standard ring and the use of the Monte Carlo method combined with select interpolation methods. The developed model may be used in conjunction with one of the known models of CMM kinematic errors to form a virtual model of a five-axis coordinate system. In addition, the developed methodology allows for the correction of identified probe head errors, thus improving measurement accuracy. Subsequent verification tests prove the correct functioning of the presented model.

  19. Environmental Anchoring of Head Direction in a Computational Model of Retrosplenial Cortex.

    Science.gov (United States)

    Bicanski, Andrej; Burgess, Neil

    2016-11-16

    Allocentric (world-centered) spatial codes driven by path integration accumulate error unless reset by environmental sensory inputs that are necessarily egocentric (body-centered). Previous models of the head direction system avoided the necessary transformation between egocentric and allocentric reference frames by placing visual cues at infinity. Here we present a model of head direction coding that copes with exclusively proximal cues by making use of a conjunctive representation of head direction and location in retrosplenial cortex. Egocentric landmark bearing of proximal cues, which changes with location, is mapped onto this retrosplenial representation. The model avoids distortions due to parallax, which occur in simple models when a single proximal cue card is used, and can also accommodate multiple cues, suggesting how it can generalize to arbitrary sensory environments. It provides a functional account of the anatomical distribution of head direction cells along Papez' circuit, of place-by-direction coding in retrosplenial cortex, the anatomical connection from the anterior thalamic nuclei to retrosplenial cortex, and the involvement of retrosplenial cortex in navigation. In addition to parallax correction, the same mechanism allows for continuity of head direction coding between connected environments, and shows how a head direction representation can be stabilized by a single within arena cue. We also make predictions for drift during exploration of a new environment, the effects of hippocampal lesions on retrosplenial cells, and on head direction coding in differently shaped environments. The activity of head direction cells signals the direction of an animal's head relative to landmarks in the world. Although driven by internal estimates of head movements, head direction cells must be kept aligned to the external world by sensory inputs, which arrive in the reference frame of the sensory receptors. We present a computational model, which proposes that

  20. [RESEARCH PROGRESS OF EXPERIMENTAL ANIMAL MODELS OF AVASCULAR NECROSIS OF FEMORAL HEAD].

    Science.gov (United States)

    Yu, Kaifu; Tan, Hongbo; Xu, Yongqing

    2015-12-01

    To summarize the current researches and progress on experimental animal models of avascular necrosis of the femoral head. Domestic and internation literature concerning experimental animal models of avascular necrosis of the femoral head was reviewed and analyzed. The methods to prepare the experimental animal models of avascular necrosis of the femoral head can be mainly concluded as traumatic methods (including surgical, physical, and chemical insult), and non-traumatic methods (including steroid, lipopolysaccharide, steroid combined with lipopolysaccharide, steroid combined with horse serum, etc). Each method has both merits and demerits, yet no ideal methods have been developed. There are many methods to prepare the experimental animal models of avascular necrosis of the femoral head, but proper model should be selected based on the aim of research. The establishment of ideal experimental animal models needs further research in future.

  1. Development, Validation and Parametric study of a 3-Year-Old Child Head Finite Element Model

    Science.gov (United States)

    Cui, Shihai; Chen, Yue; Li, Haiyan; Ruan, ShiJie

    2015-12-01

    Traumatic brain injury caused by drop and traffic accidents is an important reason for children's death and disability. Recently, the computer finite element (FE) head model has been developed to investigate brain injury mechanism and biomechanical responses. Based on CT data of a healthy 3-year-old child head, the FE head model with detailed anatomical structure was developed. The deep brain structures such as white matter, gray matter, cerebral ventricle, hippocampus, were firstly created in this FE model. The FE model was validated by comparing the simulation results with that of cadaver experiments based on reconstructing the child and adult cadaver experiments. In addition, the effects of skull stiffness on the child head dynamic responses were further investigated. All the simulation results confirmed the good biofidelity of the FE model.

  2. Head flying characteristics in heat assisted magnetic recording considering various nanoscale heat transfer models

    Science.gov (United States)

    Hu, Yueqiang; Wu, Haoyu; Meng, Yonggang; Wang, Yu; Bogy, David

    2018-01-01

    The thermal issues in heat-assisted magnetic recording (HAMR) technology have drawn much attention in the recent literature. In this paper, the head flying characteristics and thermal performance of a HAMR system during the touch-down process considering different nanoscale heat transfer models across the head-disk interface are numerically studied. An optical-thermal-mechanical coupled model is first described. The coupling efficiency of the near field transducer is found to be dependent on the head disk clearance. The shortcomings of a constant disk-temperature model are investigated, which reveals the importance of considering the disk temperature as a variable. A study of the head flying on the disk is carried out using an air conduction model and additional near-field heat transfer models. It is shown that when the head disk interface is filled with a solid material caused by the laser-induced accumulation, the heat transfer coefficient can become unexpectedly large and the head's temperature can rise beyond desirable levels. Finally, the additional head protrusion due to the laser heating is investigated.

  3. Ischemic femoral head osteonecrosis in a piglet model causes three dimensional decrease in acetabular coverage.

    Science.gov (United States)

    Upasani, Vidyadhar V; Jeffords, Megan E; Farnsworth, Christine L; Padilla, David; Lopreiato, Nick; Aruwajoye, Olumide O; Kim, Harry K W

    2017-09-15

    Legg-Calve-Perthes disease (LCPD) is a childhood form of ischemic osteonecrosis marked by development of severe femoral head deformity and premature osteoarthritis. The pathogenesis of femoral head deformity has been studied extensively using a piglet model of ischemic osteonecrosis, however, accompanying acetabular changes have not been investigated. The purpose of this study was to determine if acetabular changes accompany femoral head deformity in a well-established piglet model of LCPD and to define the acetabular changes using three dimensional computed tomography (3-D CT) and modeling. Twenty-four piglets were surgically induced with ischemic osteonecrosis on the right side. The contralateral hip was used as control. At 8 weeks postoperative, pelvi were retrieved and imaged with CT. Custom software was used to measure acetabular morphologic parameters on 3-D CT images. Moderate to severe femoral head deformities were present in all animals. Acetabula with accompanying femoral head deformity had a significant decrease in acetabular version and tilt (p femoral head deformity following ischemic osteonecrosis produces specific and predictable changes to the shape of the acetabulum. Acetabular changes described in patients with LCPD were observed in the piglet model. This model may serve as a valuable tool to elucidate the relationship between femoral head and acetabular deformities. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  4. A finite-element reciprocity solution for EEG forward modeling with realistic individual head models.

    Science.gov (United States)

    Ziegler, Erik; Chellappa, Sarah L; Gaggioni, Giulia; Ly, Julien Q M; Vandewalle, Gilles; André, Elodie; Geuzaine, Christophe; Phillips, Christophe

    2014-12-01

    We present a finite element modeling (FEM) implementation for solving the forward problem in electroencephalography (EEG). The solution is based on Helmholtz's principle of reciprocity which allows for dramatically reduced computational time when constructing the leadfield matrix. The approach was validated using a 4-shell spherical model and shown to perform comparably with two current state-of-the-art alternatives (OpenMEEG for boundary element modeling and SimBio for finite element modeling). We applied the method to real human brain MRI data and created a model with five tissue types: white matter, gray matter, cerebrospinal fluid, skull, and scalp. By calculating conductivity tensors from diffusion-weighted MR images, we also demonstrate one of the main benefits of FEM: the ability to include anisotropic conductivities within the head model. Root-mean square deviation between the standard leadfield and the leadfield including white-matter anisotropy showed that ignoring the directional conductivity of white matter fiber tracts leads to orientation-specific errors in the forward model. Realistic head models are necessary for precise source localization in individuals. Our approach is fast, accurate, open-source and freely available online. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Efficacy of visor and helmet for blast protection assessed using a computational head model

    Science.gov (United States)

    Singh, D.; Cronin, D. S.

    2017-11-01

    Head injury resulting from blast exposure has been identified as a challenge that may be addressed, in part, through improved protective systems. Existing detailed head models validated for blast loading were applied to investigate the influence of helmet visor configuration, liner properties, and shell material stiffness. Response metrics including head acceleration and intracranial pressures (ICPs) generated in brain tissue during primary blast exposure were used to assess and compare helmet configurations. The addition of a visor was found to reduce peak head acceleration and positive ICPs. However, negative ICPs associated with a potential for injury were increased when a visor and a foam liner were present. In general, the foam liner material was found to be more significant in affecting the negative ICP response than positive ICP or acceleration. Shell stiffness was found to have relatively small effects on either metric. A strap suspension system, modeled as an air gap between the head and helmet, was more effective in reducing response metrics compared to a foam liner. In cases with a foam liner, lower-density foam offered a greater reduction of negative ICPs. The models demonstrated the "underwash" effect in cases where no foam liner was present; however, the reflected pressures generated between the helmet and head did not translate to significant ICPs in adjacent tissue, when compared to peak ICPs from initial blast wave interaction. This study demonstrated that the efficacy of head protection can be expressed in terms of load transmission pathways when assessed with a detailed computational model.

  6. A structurally detailed finite element human head model for simulation of transcranial magnetic stimulation.

    Science.gov (United States)

    Chen, Ming; Mogul, David Jeffery

    2009-04-30

    Computational studies of the head utilizing finite element models (FEMs) have been used to investigate a wide variety of brain-electromagnetic (EM) field interaction phenomena including magnetic stimulation of the head using transcranial magnetic stimulation (TMS), direct electric stimulation of the brain for electroconvulsive therapy, and electroencephalography source localization. However, no human head model of sufficient complexity for studying the biophysics under these circumstances has been developed which utilizes structures at both the regional and cellular levels and provides well-defined smooth boundaries between tissues of different conductivities and orientations. The main barrier for building such accurate head models is the complex modeling procedures that include 3D object reconstruction and optimized meshing. In this study, a structurally detailed finite element model of the human head was generated that includes details to the level of cerebral gyri and sulci by combining computed tomography and magnetic resonance images. Furthermore, cortical columns that contain conductive processes of pyramidal neurons traversing the neocortical layers were included in the head model thus providing structure at or near the cellular level. These refinements provide a much more realistic model to investigate the effects of TMS on brain electrophysiology in the neocortex.

  7. A Head in Virtual Reality: Development of A Dynamic Head and Neck Model

    Science.gov (United States)

    Nguyen, Ngan; Wilson, Timothy D.

    2009-01-01

    Advances in computer and interface technologies have made it possible to create three-dimensional (3D) computerized models of anatomical structures for visualization, manipulation, and interaction in a virtual 3D environment. In the past few decades, a multitude of digital models have been developed to facilitate complex spatial learning of the…

  8. Principle Study of Head Meridian Acupoint Massage to Stress Release via Grey Data Model Analysis.

    Science.gov (United States)

    Lee, Ya-Ting

    2016-01-01

    This paper presents the scientific study of the effectiveness and action principle of head meridian acupoint massage by applying the grey data model analysis approach. First, the head massage procedure for massaging the important head meridian acupuncture points including Taiyang, Fengfu, Tianzhu, Fengqi, and Jianjing is formulated in a standard manner. Second, the status of the autonomic nervous system of each subject is evaluated by using the heart rate variability analyzer before and after the head massage following four weeks. Afterward, the physiological factors of autonomic nerves are quantitatively analyzed by using the grey data modeling theory. The grey data analysis can point out that the status of autonomic nervous system is greatly improved after the massage. The order change of the grey relationship weighting of physiological factors shows the action principle of the sympathetic and parasympathetic nerves when performing head massage. In other words, the grey data model is able to distinguish the detailed interaction of the autonomic nervous system and the head meridian acupoint massage. Thus, the stress relaxing effect of massaging head meridian acupoints is proved, which is lacked in literature. The results can be a reference principle for massage health care in practice.

  9. 3D realistic head model simulation based on transcranial magnetic stimulation.

    Science.gov (United States)

    Yang, Shuo; Xu, Guizhi; Wang, Lei; Chen, Yong; Wu, Huanli; Li, Ying; Yang, Qingxin

    2006-01-01

    Transcranial magnetic stimulation (TMS) is a powerful non-invasive tool for investigating functions in the brain. The target inside the head is stimulated with eddy currents induced in the tissue by the time-varying magnetic field. Precise spatial localization of stimulation sites is the key of efficient functional magnetic stimulations. Many researchers devote to magnetic field analysis in empty free space. In this paper, a realistic head model used in Finite Element Method has been developed. The magnetic field inducted in the head bt TMS has been analysed. This three-dimensional simulation is useful for spatial localization of stimulation.

  10. A simple method for establishing an ostrich model of femoral head osteonecrosis and collapse.

    Science.gov (United States)

    Jiang, Wenxue; Wang, Pengfei; Wan, Yanlin; Xin, Dasen; Fan, Meng

    2015-05-21

    This study aimed to develop a simple method of creating an animal model of non-trauma femoral head osteonecrosis and collapse using African ostriches with weights similar to those of humans. Eighteen African ostriches were subjected to liquid nitrogen cryo-insult in the unilateral femoral head through surgical procedures using homemade cryogenic equipment combined with tract drilling inside the femoral head. Three animals were sacrificed at postoperative weeks 6 and 12, respectively, and the remaining animals were sacrificed at postoperative week 24. Bilateral femoral heads were harvested and subjected to gross observation, histological examination using hematoxylin and eosin staining, and radiographic examination. Micro-computed tomography was performed on a portion of the specimens at postoperative week 24, and angiographic examination of the femoral head was performed before sacrificing the animals. Eight ostriches developed a limp at postoperative week 8, with a mean duration of 16.5 weeks. The postoperative femoral head specimens showed changes in contour and articular cartilage degeneration. Sagittal sectioning of the collapsed femoral head specimens revealed distinct boundaries among the osteonecrotic areas, osteosclerotic areas, and normal trabeculae. Histological examinations revealed active bone resorption in the osteonecrotic area of the subchondral bone, an increased number of fat cells, and active trabecular bone regeneration in the osteosclerotic areas. The postoperative radiographic examinations revealed that the height of the femoral head gradually decreased and progressed to collapse. Micro-computed tomography scans showed the interrupted trabecular bone with an irregular shape in the collapsed femoral head. Compared with the normal samples, angiographic findings revealed interrupted blood supply of the cryo-injured samples in some areas of the femoral heads, blood vessel narrowing, and decreased number of blood vessels in the cryo-injured areas

  11. Physical scale modeling of single free head piles under lateral loading in cohesive soils

    Directory of Open Access Journals (Sweden)

    Edgar Leonardo Salamanca-Medina

    2017-06-01

    Full Text Available This paper presents the results of the small scale modeling of free head wood piles under horizontal loading in cohesive soils, tested in order to compare the results with analytical models proposed by various authors. Characteristic Load (CLM and P-Y Curves methods were used for the prediction of lateral deflections at the head of the piles and the method proposed by Broms for estimating the ultimate lateral load. These predictions were compared with the results of the physical modeling, obtaining a good approximation between them.

  12. Novel Profiling Model and Side Effects of Helical Scan Silicon Heads

    NARCIS (Netherlands)

    Hozoi, A.; Groenland, J.P.J.; Albertini, J.B.; Lodder, J.C.

    2002-01-01

    Partial erasure of track edges was directly measured from triple-track patterns using a novel model to interpret the output profiles. The model is based on representing the read head as the sum of a reference width, wavelength independent, and two side reading effective widths that are wavelength

  13. Does Head Start differentially benefit children with risks targeted by the program’s service model?☆

    Science.gov (United States)

    Miller, Elizabeth B.; Farkas, George; Duncan, Greg J.

    2015-01-01

    Data from the Head Start Impact Study (N = 3540) were used to test for differential benefits of Head Start after one program year and after kindergarten on pre-academic and behavior outcomes for children at risk in the domains targeted by the program’s comprehensive services. Although random assignment to Head Start produced positive treatment main effects on children’s pre-academic skills and behavior problems, residualized growth models showed that random assignment to Head Start did not differentially benefit the pre-academic skills of children with risk factors targeted by the Head Start service model. The models showed detrimental impacts of Head Start for maternal-reported behavior problems of high-risk children, but slightly more positive impacts for teacher-reported behavior. Policy implications for Head Start are discussed. PMID:26379369

  14. Solving the forward problem in EEG source analysis by spherical and fdm head modeling: a comparative analysis - biomed 2009.

    Science.gov (United States)

    Vatta, Federica; Meneghini, Fabio; Esposito, Fabrino; Mininel, Stefano; Di Salle, Francesca

    2009-01-01

    Neural source localization techniques based on electroencephalography (EEG) use scalp potential data to infer the location of underlying neural activity. This procedure entails modeling the sources of EEG activity and modeling the head volume conduction process to link the modeled sources to the EEG, solving the so called EEG forward problem, and reconstructing the brain electrical activity from recorded EEG data, solving the EEG inverse problem. Many factors affect the accuracy of the forward and hence of the inverse problem solution, one of them is the shape of the head model. Realistic head models can lead to more accurate forward problem solutions, but imply heavier computational burdens in comparison to spherical models. Conversely, inverse solutions require the forward model to be computationally efficient. The aim of this study is to investigate the different general potentialities, in terms of EEG source reconstruction, which can be achieved adopting realistic or spherical geometries in head modeling. Previous studies in the literature analyzed the effect of head model geometry presenting results for particular cases of head models. In this paper, we re-address the effect of realistic geometry in head modeling, seeking for more general results by adopting the Montreal Neurological Institute (MNI) phantom model to represent a whole family of realistic head models. This paper presents results of a computer simulation study in which the potentialities of two different four-shell head models are compared, the realistic MNI-based FDM and the corresponding sensor-fitted spherical-shaped model, by means of the Point Spread Function (PSF) correlation maps, with a quantitative analysis of the accuracy in EEG source reconstruction given by head modeling refinement from the spherical to the more complex realistic FDM head modeling.

  15. Of lice and math: using models to understand and control populations of head lice.

    Directory of Open Access Journals (Sweden)

    María Fabiana Laguna

    Full Text Available In this paper we use detailed data about the biology of the head louse (pediculus humanus capitis to build a model of the evolution of head lice colonies. Using theory and computer simulations, we show that the model can be used to assess the impact of the various strategies usually applied to eradicate head lice, both conscious (treatments and unconscious (grooming. In the case of treatments, we study the difference in performance that arises when they are applied in systematic and non-systematic ways. Using some reasonable simplifying assumptions (as random mixing of human groups and the same mobility for all life stages of head lice other than eggs we model the contagion of pediculosis using only one additional parameter. It is shown that this parameter can be tuned to obtain collective infestations whose characteristics are compatible with what is given in the literature on real infestations. We analyze two scenarios: One where group members begin treatment when a similar number of lice are present in each head, and another where there is one individual who starts treatment with a much larger threshold ("superspreader". For both cases we assess the impact of several collective strategies of treatment.

  16. Development of New, Low-Head Hydropower Turbine - Modeling & Laboratory Test DE-EE0005426

    Energy Technology Data Exchange (ETDEWEB)

    Krouse, Wayne [Hydro Green Energy, Westmont, IL (United States)

    2014-12-05

    Hydro Green Energy, LLC (HGE) will complete the design, fabrication and laboratory testing of a scaled, vertically stackable, low-head hydropower turbine called the Modular Bulb Turbine (MBT). HGE will also complete a summary report that includes the laboratory testing results and analysis of the tests. Project Goals: Design, model and test modular bulb turbine for installation in numerous HGE low-head hydropower projects at non-powered USACE dams. Project Results: The sub-scale prototype was tested successfully at a leading US hydraulic laboratory. Laboratory data results agreed well with predicted results from numerical modeling.

  17. Head model and electrical source imaging: A study of 38 epileptic patients

    Directory of Open Access Journals (Sweden)

    Gwénael Birot

    2014-01-01

    We found that all head models provided very similar source locations. In patients having a positive post-operative outcome, at least 74% of the source maxima were within the resection. The median distance from the source maximum to the nearest intracranial electrode showing IED was 13.2, 15.6 and 15.6 mm for LSMAC, BEM and FEM, respectively. The study demonstrates that in clinical applications, the use of highly sophisticated and difficult to implement head models is not a crucial factor for an accurate ESI.

  18. SCDAP/RELAP5 Modeling of Heat Transfer and Flow Losses in Lower Head Porous Debris

    International Nuclear Information System (INIS)

    Coryell, E.W.; Siefken, L.J.; Paik, S.

    1998-01-01

    Designs are described for implementing models for calculating the heat transfer and flow losses in porous debris in the lower head of a reactor vessel. The COUPLE model in SCDAP/RELAP5 represents both the porous and non-porous debris that results from core material slumping into the lower head. Currently, the COUPLE model has the capability to model convective and radiative heat transfer from the surfaces of non-porous debris in a detailed manner and to model only in a simplistic manner the heat transfer from porous debris. In order to advance beyond the simplistic modeling for porous debris, designs are developed for detailed calculations of heat transfer and flow losses in porous debris. Correlations are identified for convective heat transfer in porous debris for the following modes of heat transfer; (1) forced convection to liquid, (2) forced convection to gas, (3) nucleate boiling, (4) transition boiling, and (5) film boiling. Interphase heat transfer is modeled in an approximate manner. A design is also described for implementing a model of heat transfer by radiation from debris to the interstitial fluid. A design is described for implementation of models for flow losses and interphase drag in porous debris. Since the models for heat transfer and flow losses in porous debris in the lower head are designed for general application, a design is also described for implementation of these models to the analysis of porous debris in the core region. A test matrix is proposed for assessing the capability of the implemented models to calculate the heat transfer and flow losses in porous debris. The implementation of the models described in this report is expected to improve the COUPLE code calculation of the temperature distribution in porous debris and in the lower head that supports the debris. The implementation of these models is also expected to improve the calculation of the temperature and flow distribution in porous debris in the core region

  19. Levels of detail analysis of microwave scattering from human head models for brain stroke detection

    Directory of Open Access Journals (Sweden)

    Awais Munawar Qureshi

    2017-11-01

    Full Text Available In this paper, we have presented a microwave scattering analysis from multiple human head models. This study incorporates different levels of detail in the human head models and its effect on microwave scattering phenomenon. Two levels of detail are taken into account; (i Simplified ellipse shaped head model (ii Anatomically realistic head model, implemented using 2-D geometry. In addition, heterogenic and frequency-dispersive behavior of the brain tissues has also been incorporated in our head models. It is identified during this study that the microwave scattering phenomenon changes significantly once the complexity of head model is increased by incorporating more details using magnetic resonance imaging database. It is also found out that the microwave scattering results match in both types of head model (i.e., geometrically simple and anatomically realistic, once the measurements are made in the structurally simplified regions. However, the results diverge considerably in the complex areas of brain due to the arbitrary shape interface of tissue layers in the anatomically realistic head model. After incorporating various levels of detail, the solution of subject microwave scattering problem and the measurement of transmitted and backscattered signals were obtained using finite element method. Mesh convergence analysis was also performed to achieve error free results with a minimum number of mesh elements and a lesser degree of freedom in the fast computational time. The results were promising and the E-Field values converged for both simple and complex geometrical models. However, the E-Field difference between both types of head model at the same reference point differentiated a lot in terms of magnitude. At complex location, a high difference value of 0.04236 V/m was measured compared to the simple location, where it turned out to be 0.00197 V/m. This study also contributes to provide a comparison analysis between the direct and iterative

  20. Finite element modelling of helmeted head impact under frontal ...

    Indian Academy of Sciences (India)

    CSF), brain, tentorium and falx. The finite element model of the helmet consists of shell and foam liner. ... mechanical behaviour of motorcycle helmet. ... the latter authors use a SI (Structural Intensity) approach to study power flow distribution.

  1. Realistic Matematic Approach through Numbered Head Together Learning Model

    Science.gov (United States)

    Sugihatno, A. C. M. S.; Budiyono; Slamet, I.

    2017-09-01

    Recently, the teaching process which is conducted based on teacher center affect the students interaction in the class. It causes students become less interest to participate. That is why teachers should be more creative in designing learning using other types of cooperative learning model. Therefore, this research is aimed to implement NHT with RMA in the teaching process. We utilize NHT since it is a variant of group discussion whose aim is giving a chance to the students to share their ideas related to the teacher’s question. By using NHT in the class, a teacher can give a better understanding about the material which is given with the help of Realistic Mathematics Approach (RMA) which known for its real problem contex. Meanwhile, the researcher assumes instead of selecting teaching model, Adversity Quotient (AQ) of student also influences students’ achievement. This research used the quasi experimental research. The samples is 60 students in junior high school, it was taken by using the stratified cluster random sampling technique. The results show NHT-RMA gives a better learning achievement of mathematics than direct teaching model and NHT-RMA teaching model with categorized as high AQ show different learning achievement from the students with categorized as moderate and low AQ.

  2. BrainK for Structural Image Processing: Creating Electrical Models of the Human Head

    Directory of Open Access Journals (Sweden)

    Kai Li

    2016-01-01

    Full Text Available BrainK is a set of automated procedures for characterizing the tissues of the human head from MRI, CT, and photogrammetry images. The tissue segmentation and cortical surface extraction support the primary goal of modeling the propagation of electrical currents through head tissues with a finite difference model (FDM or finite element model (FEM created from the BrainK geometries. The electrical head model is necessary for accurate source localization of dense array electroencephalographic (dEEG measures from head surface electrodes. It is also necessary for accurate targeting of cerebral structures with transcranial current injection from those surface electrodes. BrainK must achieve five major tasks: image segmentation, registration of the MRI, CT, and sensor photogrammetry images, cortical surface reconstruction, dipole tessellation of the cortical surface, and Talairach transformation. We describe the approach to each task, and we compare the accuracies for the key tasks of tissue segmentation and cortical surface extraction in relation to existing research tools (FreeSurfer, FSL, SPM, and BrainVisa. BrainK achieves good accuracy with minimal or no user intervention, it deals well with poor quality MR images and tissue abnormalities, and it provides improved computational efficiency over existing research packages.

  3. A Statistical Model of Head Asymmetry in Infants with Deformational Plagiocephaly

    DEFF Research Database (Denmark)

    Lanche, Stéphanie; Darvann, Tron Andre; Ólafsdóttir, Hildur

    2007-01-01

    Deformational plagiocephaly is a term describing cranial asymmetry and deformation commonly seen in infants. The purpose of this work was to develop a methodology for assessment and modelling of head asymmetry. The clinical population consisted of 38 infants for whom 3-dimensional surface scans...... quantitative description of the asymmetry present in the dataset....

  4. Computational modeling of the probability of destructions in total joint endoprosthesis ceramic heads using Weibull's theory

    Czech Academy of Sciences Publication Activity Database

    Janíček, P.; Fuis, Vladimír; Málek, M.

    2010-01-01

    Roč. 14, č. 4 (2010), s. 42-51 ISSN 1335-2393 Institutional research plan: CEZ:AV0Z20760514 Keywords : computational modeling * ceramic head * in vivo destructions * hip joint endoprosthesis * probabily of rupture Subject RIV: BO - Biophysics

  5. Magnetic Nanoparticle-Based Hyperthermia for Head & Neck Cancer in Mouse Models

    Science.gov (United States)

    Zhao, Qun; Wang, Luning; Cheng, Rui; Mao, Leidong; Arnold, Robert D.; Howerth, Elizabeth W.; Chen, Zhuo G.; Platt, Simon

    2012-01-01

    In this study, magnetic iron oxide nanoparticle induced hyperthermia is applied for treatment of head and neck cancer using a mouse xenograft model of human head and neck cancer (Tu212 cell line). A hyperthermia system for heating iron oxide nanoparticles was developed by using alternating magnetic fields. Both theoretical simulation and experimental studies were performed to verify the thermotherapy effect. Experimental results showed that the temperature of the tumor center has dramatically elevated from around the room temperature to about 40oC within the first 5-10 minutes. Pathological studies demonstrate epithelial tumor cell destruction associated with the hyperthermia treatment. PMID:22287991

  6. Comparison of a layered slab and an atlas head model for Monte Carlo fitting of time-domain near-infrared spectroscopy data of the adult head

    Science.gov (United States)

    Selb, Juliette; Ogden, Tyler M.; Dubb, Jay; Fang, Qianqian; Boas, David A.

    2014-01-01

    Abstract. Near-infrared spectroscopy (NIRS) estimations of the adult brain baseline optical properties based on a homogeneous model of the head are known to introduce significant contamination from extracerebral layers. More complex models have been proposed and occasionally applied to in vivo data, but their performances have never been characterized on realistic head structures. Here we implement a flexible fitting routine of time-domain NIRS data using graphics processing unit based Monte Carlo simulations. We compare the results for two different geometries: a two-layer slab with variable thickness of the first layer and a template atlas head registered to the subject’s head surface. We characterize the performance of the Monte Carlo approaches for fitting the optical properties from simulated time-resolved data of the adult head. We show that both geometries provide better results than the commonly used homogeneous model, and we quantify the improvement in terms of accuracy, linearity, and cross-talk from extracerebral layers. PMID:24407503

  7. A Dynamic Model of the Cervical Spine and Head

    Science.gov (United States)

    1981-11-01

    22314 j TECHNICAL REVIEW AND APPROVAL AFAMRL-TR-8 1-5 This report has been reviewed by the Office of Public Affairs (PA) and is releasable to the National... reviewed end is approved for publication. FOR THE COMMANDER HENN O VON GIERKE Director Biodynamilos and Bioengineering Division Air Force Aerospace...primary node in the model: -85680.75 t3 0 e t < 0.0142 seeU (t) 4 11203.19 [ - 0.34t 2 + 0.004828t - 2.2853 x 10- 0.0142 S t 1 0.034 The Ti vertebra

  8. Kinematic Model-Based Pedestrian Dead Reckoning for Heading Correction and Lower Body Motion Tracking

    Directory of Open Access Journals (Sweden)

    Min Su Lee

    2015-11-01

    Full Text Available In this paper, we present a method for finding the enhanced heading and position of pedestrians by fusing the Zero velocity UPdaTe (ZUPT-based pedestrian dead reckoning (PDR and the kinematic constraints of the lower human body. ZUPT is a well known algorithm for PDR, and provides a sufficiently accurate position solution for short term periods, but it cannot guarantee a stable and reliable heading because it suffers from magnetic disturbance in determining heading angles, which degrades the overall position accuracy as time passes. The basic idea of the proposed algorithm is integrating the left and right foot positions obtained by ZUPTs with the heading and position information from an IMU mounted on the waist. To integrate this information, a kinematic model of the lower human body, which is calculated by using orientation sensors mounted on both thighs and calves, is adopted. We note that the position of the left and right feet cannot be apart because of the kinematic constraints of the body, so the kinematic model generates new measurements for the waist position. The Extended Kalman Filter (EKF on the waist data that estimates and corrects error states uses these measurements and magnetic heading measurements, which enhances the heading accuracy. The updated position information is fed into the foot mounted sensors, and reupdate processes are performed to correct the position error of each foot. The proposed update-reupdate technique consequently ensures improved observability of error states and position accuracy. Moreover, the proposed method provides all the information about the lower human body, so that it can be applied more effectively to motion tracking. The effectiveness of the proposed algorithm is verified via experimental results, which show that a 1.25% Return Position Error (RPE with respect to walking distance is achieved.

  9. Kinematic Model-Based Pedestrian Dead Reckoning for Heading Correction and Lower Body Motion Tracking.

    Science.gov (United States)

    Lee, Min Su; Ju, Hojin; Song, Jin Woo; Park, Chan Gook

    2015-11-06

    In this paper, we present a method for finding the enhanced heading and position of pedestrians by fusing the Zero velocity UPdaTe (ZUPT)-based pedestrian dead reckoning (PDR) and the kinematic constraints of the lower human body. ZUPT is a well known algorithm for PDR, and provides a sufficiently accurate position solution for short term periods, but it cannot guarantee a stable and reliable heading because it suffers from magnetic disturbance in determining heading angles, which degrades the overall position accuracy as time passes. The basic idea of the proposed algorithm is integrating the left and right foot positions obtained by ZUPTs with the heading and position information from an IMU mounted on the waist. To integrate this information, a kinematic model of the lower human body, which is calculated by using orientation sensors mounted on both thighs and calves, is adopted. We note that the position of the left and right feet cannot be apart because of the kinematic constraints of the body, so the kinematic model generates new measurements for the waist position. The Extended Kalman Filter (EKF) on the waist data that estimates and corrects error states uses these measurements and magnetic heading measurements, which enhances the heading accuracy. The updated position information is fed into the foot mounted sensors, and reupdate processes are performed to correct the position error of each foot. The proposed update-reupdate technique consequently ensures improved observability of error states and position accuracy. Moreover, the proposed method provides all the information about the lower human body, so that it can be applied more effectively to motion tracking. The effectiveness of the proposed algorithm is verified via experimental results, which show that a 1.25% Return Position Error (RPE) with respect to walking distance is achieved.

  10. A reanalysis of football impact reconstructions for head kinematics and finite element modeling.

    Science.gov (United States)

    Sanchez, Erin J; Gabler, Lee F; Good, Ann B; Funk, James R; Crandall, Jeff R; Panzer, Matthew B

    2018-03-14

    Head kinematics generated by laboratory reconstructions of professional football helmet impacts have been applied to computational models to study the biomechanics of concussion. Since the original publication of this data, techniques for evaluating accelerometer consistency and error correction have been developed. This study applies these techniques to the original reconstruction data and reanalyzes the results given the current state of concussion biomechanics. Consistency checks were applied to the sensor data collected in the head of each test dummy. Inconsistent data were corrected using analytical techniques, and head kinematics were recalculated from the corrected data. Reconstruction videos were reviewed to identify artefactual impacts during the reconstruction to establish the region of applicability for simulations. Corrected head kinematics were input into finite element brain models to investigate strain response to the corrected dataset. Multiple reconstruction cases had inconsistent sensor arrays caused by a problematic sensor; corrections to the arrays caused changes in calculated rotational head motion. These corrections increased median peak angular velocity for the concussion cases from 35.6 to 41.5 rad/s. Using the original kinematics resulted in an average error of 20% in maximum principal strain results for each case. Simulations of the reconstructions also demonstrated that simulation lengths less than 40 ms did not capture the entire brain strain response and under-predicted strain. This study corrects data that were used to determine concussion risk, and indicates altered head angular motion and brain strain response for many reconstructions. Conclusions based on the original data should be re-examined based on this new study. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. 3D maxillofacial soft-tissue model in laser scanned head

    Science.gov (United States)

    Liang, Haidong; Hughes, Steven

    1998-05-01

    The purpose of this study is to incorporate thickness data into a soft tissue model in a laser scanned head data base, for use in FEA modeling of the behavior of the soft tissue layer under mechanical loads. Using a magnetic-based, spatial acquisition system (Polhemus) into which is incorporated an ultrasound sensor the position and orientation of tissue thickness vectors are obtained. By combining this with 3D high resolution head shape data from our laser scanner, a model of the head complete with soft tissue thickness is to be developed. We have implemented an initial version of software for the integration of laser scanning and facial soft tissue thickness measurement. The package displays facial images and performs basic imaging processing. The co-ordinate systems of the two methods are matched with the help of markers fixed on known head landmarks and a 3D digitiser (Polhemus). The computed source locations can be instantly superimposed on the facial images during the analysis.

  12. Electric field distribution in a finite-volume head model of deep brain stimulation.

    Science.gov (United States)

    Grant, Peadar F; Lowery, Madeleine M

    2009-11-01

    This study presents a whole-head finite element model of deep brain stimulation to examine the effect of electrical grounding, the finite conducting volume of the head, and scalp, skull and cerebrospinal fluid layers. The impedance between the stimulating and reference electrodes in the whole-head model was found to lie within clinically reported values when the reference electrode was incorporated on a localized surface in the model. Incorporation of the finite volume of the head and inclusion of surrounding outer tissue layers reduced the magnitude of the electric field and activating function by approximately 20% in the region surrounding the electrode. Localized distortions of the electric field were also observed when the electrode was placed close to the skull. Under bipolar conditions the effect of the finite conducting volume was shown to be negligible. The results indicate that, for monopolar stimulation, incorporation of the finite volume and outer tissue layers can alter the magnitude of the electric field and activating function when the electrode is deep within the brain, and may further affect the shape if the electrode is close to the skull.

  13. An extension of Box-Jenkins transfer/noise models for spatial interpolation of groundwater head series

    NARCIS (Netherlands)

    Geer, F.C. van; Zuur, A.F.

    1997-01-01

    This paper advocates an approach to extend single-output Box-Jenkins transfer/noise models for several groundwater head series to a multiple-output transfer/noise model. The approach links several groundwater head series and enables a spatial interpolation in terms of time series analysis. Our

  14. Assessment of model-based image-matching for future reconstruction of unhelmeted sport head impact kinematics.

    Science.gov (United States)

    Tierney, Gregory J; Joodaki, Hamed; Krosshaug, Tron; Forman, Jason L; Crandall, Jeff R; Simms, Ciaran K

    2018-03-01

    Player-to-player contact inherent in many unhelmeted sports means that head impacts are a frequent occurrence. Model-Based Image-Matching (MBIM) provides a technique for the assessment of three-dimensional linear and rotational motion patterns from multiple camera views of a head impact event, but the accuracy is unknown for this application. The goal of this study is to assess the accuracy of the MBIM method relative to reflective marker-based motion analysis data for estimating six degree of freedom head displacements and velocities in a staged pedestrian impact scenario at 40 km/h. Results showed RMS error was under 20 mm for all linear head displacements and 0.01-0.04 rad for head rotations. For velocities, the MBIM method yielded RMS errors between 0.42 and 1.29 m/s for head linear velocities and 3.53-5.38 rad/s for angular velocities. This method is thus beneficial as a tool to directly measure six degree of freedom head positional data from video of sporting head impacts, but velocity data is less reliable. MBIM data, combined in future with velocity/acceleration data from wearable sensors could be used to provide input conditions and evaluate the outputs of multibody and finite element head models for brain injury assessment of sporting head impacts.

  15. Rapidly re-computable EEG (electroencephalography) forward models for realistic head shapes

    Energy Technology Data Exchange (ETDEWEB)

    Ermer, J. J. (John J.); Mosher, J. C. (John C.); Baillet, S. (Sylvain); Leahy, R. M. (Richard M.)

    2001-01-01

    Solution of the EEG source localization (inverse) problem utilizing model-based methods typically requires a significant number of forward model evaluations. For subspace based inverse methods like MUSIC [6], the total number of forward model evaluations can often approach an order of 10{sup 3} or 10{sup 4}. Techniques based on least-squares minimization may require significantly more evaluations. The observed set of measurements over an M-sensor array is often expressed as a linear forward spatio-temporal model of the form: F = GQ + N (1) where the observed forward field F (M-sensors x N-time samples) can be expressed in terms of the forward model G, a set of dipole moment(s) Q (3xP-dipoles x N-time samples) and additive noise N. Because of their simplicity, ease of computation, and relatively good accuracy, multi-layer spherical models [7] (or fast approximations described in [1], [7]) have traditionally been the 'forward model of choice' for approximating the human head. However, approximation of the human head via a spherical model does have several key drawbacks. By its very shape, the use of a spherical model distorts the true distribution of passive currents in the skull cavity. Spherical models also require that the sensor positions be projected onto the fitted sphere (Fig. 1), resulting in a distortion of the true sensor-dipole spatial geometry (and ultimately the computed surface potential). The use of a single 'best-fitted' sphere has the added drawback of incomplete coverage of the inner skull region, often ignoring areas such as the frontal cortex. In practice, this problem is typically countered by fitting additional sphere(s) to those region(s) not covered by the primary sphere. The use of these additional spheres results in added complication to the forward model. Using high-resolution spatial information obtained via X-ray CT or MR imaging, a realistic head model can be formed by tessellating the head into a set of contiguous

  16. A finite element head and neck model as a supportive tool for deformable image registration.

    Science.gov (United States)

    Kim, Jihun; Saitou, Kazuhiro; Matuszak, Martha M; Balter, James M

    2016-07-01

    A finite element (FE) head and neck model was developed as a tool to aid investigations and development of deformable image registration and patient modeling in radiation oncology. Useful aspects of a FE model for these purposes include ability to produce realistic deformations (similar to those seen in patients over the course of treatment) and a rational means of generating new configurations, e.g., via the application of force and/or displacement boundary conditions. The model was constructed based on a cone-beam computed tomography image of a head and neck cancer patient. The three-node triangular surface meshes created for the bony elements (skull, mandible, and cervical spine) and joint elements were integrated into a skeletal system and combined with the exterior surface. Nodes were additionally created inside the surface structures which were composed of the three-node triangular surface meshes, so that four-node tetrahedral FE elements were created over the whole region of the model. The bony elements were modeled as a homogeneous linear elastic material connected by intervertebral disks. The surrounding tissues were modeled as a homogeneous linear elastic material. Under force or displacement boundary conditions, FE analysis on the model calculates approximate solutions of the displacement vector field. A FE head and neck model was constructed that skull, mandible, and cervical vertebrae were mechanically connected by disks. The developed FE model is capable of generating realistic deformations that are strain-free for the bony elements and of creating new configurations of the skeletal system with the surrounding tissues reasonably deformed. The FE model can generate realistic deformations for skeletal elements. In addition, the model provides a way of evaluating the accuracy of image alignment methods by producing a ground truth deformation and correspondingly simulated images. The ability to combine force and displacement conditions provides

  17. A mouse model of weight-drop closed head injury: emphasis on cognitive and neurological deficiency

    Directory of Open Access Journals (Sweden)

    Igor Khalin

    2016-01-01

    Full Text Available Traumatic brain injury (TBI is a leading cause of death and disability in individuals worldwide. Producing a clinically relevant TBI model in small-sized animals remains fairly challenging. For good screening of potential therapeutics, which are effective in the treatment of TBI, animal models of TBI should be established and standardized. In this study, we established mouse models of closed head injury using the Shohami weight-drop method with some modifications concerning cognitive deficiency assessment and provided a detailed description of the severe TBI animal model. We found that 250 g falling weight from 2 cm height produced severe closed head injury in C57BL/6 male mice. Cognitive disorders in mice with severe closed head injury could be detected using passive avoidance test on day 7 after injury. Findings from this study indicate that weight-drop injury animal models are suitable for further screening of brain neuroprotectants and potentially are similar to those seen in human TBI.

  18. Impact of head modeling and sensor types in localizing human gamma-band oscillations.

    Science.gov (United States)

    Mideksa, K G; Hoogenboom, N; Hellriegel, H; Krause, H; Schnitzler, A; Deuschl, G; Raethjen, J; Heute, U; Muthuraman, M

    2014-01-01

    An effective mechanism in neuronal communication is oscillatory neuronal synchronization. The neuronal gamma-band (30-100 Hz) synchronization is associated with attention which is induced by a certain visual stimuli. Numerous studies have shown that the gamma-band activity is observed in the visual cortex. However, impact of different head modeling techniques and sensor types to localize gamma-band activity have not yet been reported. To do this, the brain activity was recorded using 306 magnetoencephalography (MEG) sensors, consisting of 102 magnetometers and 102 pairs of planar gradiometers (one measuring the derivative of the magnetic field along the latitude and the other along the longitude), and the data were analyzed with respect to time, frequency, and location of the strongest response. The spherical head models with a single-shell and overlapping spheres (local sphere) have been used as a forward model for calculating the external magnetic fields generated from the gamma-band activity. For each sensor type, the subject-specific frequency range of the gamma-band activity was obtained from the spectral analysis. The identified frequency range of interest with the highest gamma-band activity is then localized using a spatial-filtering technique known as dynamic imaging of coherent sources (DICS). The source analysis for all the subjects revealed that the gradiometer sensors which measure the derivative along the longitude, showed sources close to the visual cortex (cuneus) as compared to the other gradiometer sensors which measure the derivative along the latitude. However, using the magnetometer sensors, it was not possible to localize the sources in the region of interest. When comparing the two head models, the local-sphere model helps in localizing the source more focally as compared to the single-shell head model.

  19. Testing the dual-route model of perceived gaze direction: Linear combination of eye and head cues.

    Science.gov (United States)

    Otsuka, Yumiko; Mareschal, Isabelle; Clifford, Colin W G

    2016-06-01

    We have recently proposed a dual-route model of the effect of head orientation on perceived gaze direction (Otsuka, Mareschal, Calder, & Clifford, 2014; Otsuka, Mareschal, & Clifford, 2015), which computes perceived gaze direction as a linear combination of eye orientation and head orientation. By parametrically manipulating eye orientation and head orientation, we tested the adequacy of a linear model to account for the effect of horizontal head orientation on perceived direction of gaze. Here, participants adjusted an on-screen pointer toward the perceived gaze direction in two image conditions: Normal condition and Wollaston condition. Images in the Normal condition included a change in the visible part of the eye along with the change in head orientation, while images in the Wollaston condition were manipulated to have identical eye regions across head orientations. Multiple regression analysis with explanatory variables of eye orientation and head orientation revealed that linear models account for most of the variance both in the Normal condition and in the Wollaston condition. Further, we found no evidence that the model with a nonlinear term explains significantly more variance. Thus, the current study supports the dual-route model that computes the perceived gaze direction as a linear combination of eye orientation and head orientation.

  20. Which Biomarker is most Effective to Determine Severity of Acute Head Trauma in the Experimental Animal Head Trauma Model?

    Science.gov (United States)

    Demir, Ozgur; Deniz, Fatih Ersay; Benli, Ismail; Oksuz, Erol; Demir, Osman; Butun, Ilknur

    2016-01-01

    Because of the need for effective method to determine the severity of head trauma, the importance of biomarkers is recognized recently. This study aims to analyze the values of sera levels of some biomarkers and the relation with their tissue levels in acute head injury. In this study, rats were divided into three groups (mild head trauma, severe head trauma and control group). All rats were anaesthetized. Weightdrop method was used as trauma method. Blood samples were obtained five minutes after trauma when the acute effects of trauma occurred. Then whole brains of rats were excised. Levels of biomarkers were investigated in the sera samples and homogenized brain tissues biochemically. Significant differences in the sera GFAP (p=0.015) and insulin (p=0.011) levels were observed. Very significant difference in the sera nNOS level was observed. Extremely significant difference in the tissue IL-6 (p trauma severity. Sera GFAP and insulin are also capable to show trauma severity in the very acute period of postinjury. Tissue levels of the biomarkers except insulin are higher than their sera levels.

  1. Radiobiological modeling of interplay between accelerated repopulation and altered fractionation schedules in head and neck cancer

    Directory of Open Access Journals (Sweden)

    Marcu Loredana

    2009-01-01

    Full Text Available Head and neck cancer represents a challenge for radiation oncologists due to accelerated repopulation of cancer cells during treatment. This study aims to simulate, using Monte Carlo methods, the response of a virtual head and neck tumor to both conventional and altered fractionation schedules in radiotherapy when accelerated repopulation is considered. Although clinical trials are indispensable for evaluation of novel therapeutic techniques, they are time-consuming processes which involve many complex and variable factors for success. Models can overcome some of the limitations encountered by trials as they are able to simulate in less complex environment tumor cell kinetics and dynamics, interaction processes between cells and ionizing radiation and their outcome. Conventional, hyperfractionated and accelerated treatment schedules have been implemented in a previously developed tumor growth model which also incorporates tumor repopulation during treatment. This study focuses on the influence of three main treatment-related parameters, dose per fraction, inter fraction interval and length of treatment gap and gap timing based on RTOG trial data on head and neck cancer, on tumor control. The model has shown that conventionally fractionated radiotherapy is not able to eradicate the stem population of the tumor. Therefore, new techniques such as hyperfractionated/ accelerated radiotherapy schedules should be employed. Furthermore, the correct selection of schedule-related parameters (dose per fraction, time between fractions, treatment gap scheduling is crucial in overcoming accelerated repopulation. Modeling of treatment regimens and their input parameters can offer better understanding of the radiobiological interactions and also treatment outcome.

  2. Numerical model (switchable/dual model) of the human head for rigid body and finite elements applications.

    Science.gov (United States)

    Tabacu, Stefan

    2015-01-01

    In this paper, a methodology for the development and validation of a numerical model of the human head using generic procedures is presented. All steps required, starting with the model generation, model validation and applications will be discussed. The proposed model may be considered as a dual one due to its capabilities to switch from deformable to a rigid body according to the application's requirements. The first step is to generate the numerical model of the human head using geometry files or medical images. The required stiffness and damping for the elastic connection used for the rigid body model are identified by performing a natural frequency analysis. The presented applications for model validation are related to impact analysis. The first case is related to Nahum's (Nahum and Smith 1970) experiments pressure data being evaluated and a pressure map generated using the results from discrete elements. For the second case, the relative displacement between the brain and the skull is evaluated according to Hardy's (Hardy WH, Foster CD, Mason, MJ, Yang KH, King A, Tashman S. 2001.Investigation of head injury mechanisms using neutral density technology and high-speed biplanar X-ray. Stapp Car Crash J. 45:337-368, SAE Paper 2001-22-0016) experiments. The main objective is to validate the rigid model as a quick and versatile tool for acquiring the input data for specific brain analyses.

  3. On spherical symmetry modelling of DNA packing within bacteriophage heads according to small angle scattering data

    International Nuclear Information System (INIS)

    Dembo, A.T.; Tikhonychev, V.V.

    1983-01-01

    Spherical symmetry models were used for interpretation of X-ray small angle scattering curves of bacteriophage solutions. These models were built of concentric spherical layers of finite thickness with various scattering densities. The attention was attached to the ripple intensity of DNA packing maximum. In model calculations such parameters as external radius, scattering densities, number of DNA-imitating layers and internal radii were changed. The results show that the fine structure of DNA packing maximum depends on the overall shape and size of the region occupied by DNA inside the bacteriophage head. (author)

  4. Modeling and Optimization of Airbag Helmets for Preventing Head Injuries in Bicycling.

    Science.gov (United States)

    Kurt, Mehmet; Laksari, Kaveh; Kuo, Calvin; Grant, Gerald A; Camarillo, David B

    2017-04-01

    Bicycling is the leading cause of sports-related traumatic brain injury. Most of the current bike helmets are made of expanded polystyrene (EPS) foam and ultimately designed to prevent blunt trauma, e.g., skull fracture. However, these helmets have limited effectiveness in preventing brain injuries. With the availability of high-rate micro-electrical-mechanical systems sensors and high energy density batteries, a new class of helmets, i.e., expandable helmets, can sense an impending collision and expand to protect the head. By allowing softer liner medium and larger helmet sizes, this novel approach in helmet design provides the opportunity to achieve much lower acceleration levels during collision and may reduce the risk of brain injury. In this study, we first develop theoretical frameworks to investigate impact dynamics of current EPS helmets and airbag helmets-as a form of expandable helmet design. We compared our theoretical models with anthropomorphic test dummy drop test experiments. Peak accelerations obtained from these experiments with airbag helmets achieve up to an 8-fold reduction in the risk of concussion compared to standard EPS helmets. Furthermore, we construct an optimization framework for airbag helmets to minimize concussion and severe head injury risks at different impact velocities, while avoiding excessive deformation and bottoming-out. An optimized airbag helmet with 0.12 m thickness at 72 ± 8 kPa reduces the head injury criterion (HIC) value to 190 ± 25 at 6.2 m/s head impact velocity compared to a HIC of 1300 with a standard EPS helmet. Based on a correlation with previously reported HIC values in the literature, this airbag helmet design substantially reduces the risks of severe head injury up to 9 m/s.

  5. Development of asymptotic models in ultrasonic non destructive techniques (NDT): elastic waves interaction with geometrical irregularities and head waves modeling

    International Nuclear Information System (INIS)

    Ferrand, Adrien

    2014-01-01

    The head wave is the first arrival wave received during a TOFD (Time Of Flight Diffraction) inspection. The TOFD technique is a classical ultrasonic NDT (Non Destructive Testing) inspection method employing two piezoelectric transducers which are symmetrically placed facing each other with a constant spacing above the inspected specimen surface. The head wave propagation along an irregular entry surface is shown by a numerical study to be not only a surface propagation phenomenon, as for the plane surface case, but also involves a bulk propagation phenomenon caused by diffractions of the ultrasonic wave field on the surface irregularities. In order to model theses phenomena, a generic ray tracing method based on the generalized Fermat's principle has been developed and establishes the effective path of any ultrasonic propagating wave in a specimen of irregular surface, notably including the effective head wave path. The diffraction phenomena evaluation by amplitude models using a ray approach allows to provide a complete simulation (time of flight, wave front and amplitude) of the head wave for numerous kinds of surface irregularity. Theoretical and experimental validations of the developed simulation tool have been carried out and have proven successful. (author) [fr

  6. Resistor mesh model of a spherical head: part 1: applications to scalp potential interpolation.

    Science.gov (United States)

    Chauveau, N; Morucci, J P; Franceries, X; Celsis, P; Rigaud, B

    2005-11-01

    A resistor mesh model (RMM) has been implemented to describe the electrical properties of the head and the configuration of the intracerebral current sources by simulation of forward and inverse problems in electroencephalogram/event related potential (EEG/ERP) studies. For this study, the RMM representing the three basic tissues of the human head (brain, skull and scalp) was superimposed on a spherical volume mimicking the head volume: it included 43 102 resistances and 14 123 nodes. The validation was performed with reference to the analytical model by consideration of a set of four dipoles close to the cortex. Using the RMM and the chosen dipoles, four distinct families of interpolation technique (nearest neighbour, polynomial, splines and lead fields) were tested and compared so that the scalp potentials could be recovered from the electrode potentials. The 3D spline interpolation and the inverse forward technique (IFT) gave the best results. The IFT is very easy to use when the lead-field matrix between scalp electrodes and cortex nodes has been calculated. By simple application of the Moore-Penrose pseudo inverse matrix to the electrode cap potentials, a set of current sources on the cortex is obtained. Then, the forward problem using these cortex sources renders all the scalp potentials.

  7. Automatic extraction of soft tissues from 3D MRI head images using model driven analysis

    International Nuclear Information System (INIS)

    Jiang, Hao; Yamamoto, Shinji; Imao, Masanao.

    1995-01-01

    This paper presents an automatic extraction system (called TOPS-3D : Top Down Parallel Pattern Recognition System for 3D Images) of soft tissues from 3D MRI head images by using model driven analysis algorithm. As the construction of system TOPS we developed, two concepts have been considered in the design of system TOPS-3D. One is the system having a hierarchical structure of reasoning using model information in higher level, and the other is a parallel image processing structure used to extract plural candidate regions for a destination entity. The new points of system TOPS-3D are as follows. (1) The TOPS-3D is a three-dimensional image analysis system including 3D model construction and 3D image processing techniques. (2) A technique is proposed to increase connectivity between knowledge processing in higher level and image processing in lower level. The technique is realized by applying opening operation of mathematical morphology, in which a structural model function defined in higher level by knowledge representation is immediately used to the filter function of opening operation as image processing in lower level. The system TOPS-3D applied to 3D MRI head images consists of three levels. First and second levels are reasoning part, and third level is image processing part. In experiments, we applied 5 samples of 3D MRI head images with size 128 x 128 x 128 pixels to the system TOPS-3D to extract the regions of soft tissues such as cerebrum, cerebellum and brain stem. From the experimental results, the system is robust for variation of input data by using model information, and the position and shape of soft tissues are extracted corresponding to anatomical structure. (author)

  8. Hypothyroidism after primary radiotherapy for head and neck squamous cell carcinoma: Normal tissue complication probability modeling with latent time correction

    DEFF Research Database (Denmark)

    Rønjom, Marianne Feen; Brink, Carsten; Bentzen, Søren

    2013-01-01

    To develop a normal tissue complication probability (NTCP) model of radiation-induced biochemical hypothyroidism (HT) after primary radiotherapy for head and neck squamous cell carcinoma (HNSCC) with adjustment for latency and clinical risk factors.......To develop a normal tissue complication probability (NTCP) model of radiation-induced biochemical hypothyroidism (HT) after primary radiotherapy for head and neck squamous cell carcinoma (HNSCC) with adjustment for latency and clinical risk factors....

  9. Evaluation of three-dimensional anisotropic head model for mapping realistic electromagnetic fields of brain tissues

    Directory of Open Access Journals (Sweden)

    Woo Chul Jeong

    2015-08-01

    Full Text Available Electromagnetic fields provide fundamental data for the imaging of electrical tissue properties, such as conductivity and permittivity, in recent magnetic resonance (MR-based tissue property mapping. The induced voltage, current density, and magnetic flux density caused by externally injected current are critical factors for determining the image quality of electrical tissue conductivity. As a useful tool to identify bio-electromagnetic phenomena, precise approaches are required to understand the exact responses inside the human body subject to an injected currents. In this study, we provide the numerical simulation results of electromagnetic field mapping of brain tissues using a MR-based conductivity imaging method. First, we implemented a realistic three-dimensional human anisotropic head model using high-resolution anatomical and diffusion tensor MR images. The voltage, current density, and magnetic flux density of brain tissues were imaged by injecting 1 mA of current through pairs of electrodes on the surface of our head model. The current density map of anisotropic brain tissues was calculated from the measured magnetic flux density based on the linear relationship between the water diffusion tensor and the electrical conductivity tensor. Comparing the current density to the previous isotropic model, the anisotropic model clearly showed the differences between the brain tissues. This originates from the enhanced signals by the inherent conductivity contrast as well as the actual tissue condition resulting from the injected currents.

  10. Field Distribution of Transcranial Static Magnetic Stimulation in Realistic Human Head Model.

    Science.gov (United States)

    Tharayil, Joseph J; Goetz, Stefan M; Bernabei, John M; Peterchev, Angel V

    2017-10-10

    The objective of this work was to characterize the magnetic field (B-field) that arises in a human brain model from the application of transcranial static magnetic field stimulation (tSMS). The spatial distribution of the B-field magnitude and gradient of a cylindrical, 5.08 cm × 2.54 cm NdFeB magnet were simulated in air and in a human head model using the finite element method and calibrated with measurements in air. The B-field was simulated for magnet placements over prefrontal, motor, sensory, and visual cortex targets. The impact of magnetic susceptibility of head tissues on the B-field was quantified. Peak B-field magnitude and gradient respectively ranged from 179-245 mT and from 13.3-19.0 T/m across the cortical targets. B-field magnitude, focality, and gradient decreased with magnet-cortex distance. The variation in B-field strength and gradient across the anatomical targets largely arose from the magnet-cortex distance. Head magnetic susceptibilities had negligible impact on the B-field characteristics. The half-maximum focality of the tSMS B-field ranged from 7-12 cm 3 . This is the first presentation and characterization of the three-dimensional (3D) spatial distribution of the B-field generated in a human brain model by tSMS. These data can provide quantitative dosing guidance for tSMS applications across various cortical targets and subjects. The finding that the B-field gradient is high near the magnet edges should be considered in studies where neural tissue is placed close to the magnet. The observation that susceptibility has negligible effects confirms assumptions in the literature. © 2017 International Neuromodulation Society.

  11. Cortical imaging on a head template: a simulation study using a resistor mesh model (RMM).

    Science.gov (United States)

    Chauveau, Nicolas; Franceries, Xavier; Aubry, Florent; Celsis, Pierre; Rigaud, Bernard

    2008-09-01

    The T1 head template model used in Statistical Parametric Mapping Version 2000 (SPM2), was segmented into five layers (scalp, skull, CSF, grey and white matter) and implemented in 2 mm voxels. We designed a resistor mesh model (RMM), based on the finite volume method (FVM) to simulate the electrical properties of this head model along the three axes for each voxel. Then, we introduced four dipoles of high eccentricity (about 0.8) in this RMM, separately and simultaneously, to compute the potentials for two sets of conductivities. We used the direct cortical imaging technique (CIT) to recover the simulated dipoles, using 60 or 107 electrodes and with or without addition of Gaussian white noise (GWN). The use of realistic conductivities gave better CIT results than standard conductivities, lowering the blurring effect on scalp potentials and displaying more accurate position areas when CIT was applied to single dipoles. Simultaneous dipoles were less accurately localized, but good qualitative and stable quantitative results were obtained up to 5% noise level for 107 electrodes and up to 10% noise level for 60 electrodes, showing that a compromise must be found to optimize both the number of electrodes and the noise level. With the RMM defined in 2 mm voxels, the standard 128-electrode cap and 5% noise appears to be the upper limit providing reliable source positions when direct CIT is used. The admittance matrix defining the RMM is easy to modify so as to adapt to different conductivities. The next step will be the adaptation of individual real head T2 images to the RMM template and the introduction of anisotropy using diffusion imaging (DI).

  12. MODEL PEMBELAJARAN NUMBERED HEAD TOGETHER (NHT UNTUK MENINGKATKAN PERAN AKTIF SISWA BELAJAR MATA PELAJARAN SISTEM REM

    Directory of Open Access Journals (Sweden)

    Subur Riyono

    2016-12-01

    Full Text Available The Implementation of Numbered Head Together (NHT learning model to Enhance the students Active Role in Learning the Brake System. A thesis of Machine Engginering Education Study Program Faculty of Teacher Training and Educatioon of Sarjanawiyata Tamansiswa University Yogyakarta, 2016.The type of this research is action research including three cycles. Each cycle is conducted by four stages including 1. Planning 2. Implementing 3. Observing and 4. Reflexting. In collecting the Data, the researcher appied test, observation as well as document. The technique used in analyzing the observation sheet and test is quantitive deskriptive.  The result of this research showed that the implementation of Numbered Head Together (NHT learning model had enhanched both the students learning Active Role and the students’ learning results of the brake system subject to each cycle. It is proved by the increasing result of the observation sheet of the students learning Active Role from which the first cycle 44,57% having increased to the second cycle 16,57% becoming 61,14% and in the third cycle having increased 25,57% becoming 86,71%. Furthermore, based on the learning result test  of the first cycle gave the average grade of the pre test 62,28%, the average grade of the post test then 60,71%, the average grade 69,57% so the learning result increased 8,86% and in the second cycle gave the average grade of pretest 62,28% and the average post test then 75,42% increased the learning result 13,14% and the the test of the third cycle, the average pre test 65,14% and the average post test 83,42%.. Due to the research findings, it can be concluded that the implementation of the Numbered Head Together (NHT learning model can enhance the students learning Active Role as well as the results of the students learning in the brake system.

  13. MIDA: A Multimodal Imaging-Based Detailed Anatomical Model of the Human Head and Neck.

    Directory of Open Access Journals (Sweden)

    Maria Ida Iacono

    Full Text Available Computational modeling and simulations are increasingly being used to complement experimental testing for analysis of safety and efficacy of medical devices. Multiple voxel- and surface-based whole- and partial-body models have been proposed in the literature, typically with spatial resolution in the range of 1-2 mm and with 10-50 different tissue types resolved. We have developed a multimodal imaging-based detailed anatomical model of the human head and neck, named "MIDA". The model was obtained by integrating three different magnetic resonance imaging (MRI modalities, the parameters of which were tailored to enhance the signals of specific tissues: i structural T1- and T2-weighted MRIs; a specific heavily T2-weighted MRI slab with high nerve contrast optimized to enhance the structures of the ear and eye; ii magnetic resonance angiography (MRA data to image the vasculature, and iii diffusion tensor imaging (DTI to obtain information on anisotropy and fiber orientation. The unique multimodal high-resolution approach allowed resolving 153 structures, including several distinct muscles, bones and skull layers, arteries and veins, nerves, as well as salivary glands. The model offers also a detailed characterization of eyes, ears, and deep brain structures. A special automatic atlas-based segmentation procedure was adopted to include a detailed map of the nuclei of the thalamus and midbrain into the head model. The suitability of the model to simulations involving different numerical methods, discretization approaches, as well as DTI-based tensorial electrical conductivity, was examined in a case-study, in which the electric field was generated by transcranial alternating current stimulation. The voxel- and the surface-based versions of the models are freely available to the scientific community.

  14. Reply to Discussion by Zekai Șen on "Modeling karst spring hydrograph recession based on head drop at sinkholes"

    Science.gov (United States)

    Field, Malcolm S.; Goldscheider, Nico; Li, Guangquan

    2018-02-01

    We are pleased to learn that the model presented in our paper dealing with the "modeling karst spring hydrograph recession based on head drop at sinkholes," published in the Journal of Hydrology in 2016 (Li et al., 2016), is of interest to readers of this journal. Our study presented a new non-exponential model for assessing spring hydrographs in terms of head drop at flooded sinkholes, as an extension of an earlier model proposed by Li and Field (2014). In both papers, we used two spring hydrographs measured in the St. Marks Karst Watershed in northwest Florida to test the applicability and to verify the validity of our models.

  15. Mechanics of blast loading on the head models in the study of traumatic brain injury using experimental and computational approaches.

    Science.gov (United States)

    Ganpule, S; Alai, A; Plougonven, E; Chandra, N

    2013-06-01

    Blast waves generated by improvised explosive devices can cause mild, moderate to severe traumatic brain injury in soldiers and civilians. To understand the interactions of blast waves on the head and brain and to identify the mechanisms of injury, compression-driven air shock tubes are extensively used in laboratory settings to simulate the field conditions. The overall goal of this effort is to understand the mechanics of blast wave-head interactions as the blast wave traverses the head/brain continuum. Toward this goal, surrogate head model is subjected to well-controlled blast wave profile in the shock tube environment, and the results are analyzed using combined experimental and numerical approaches. The validated numerical models are then used to investigate the spatiotemporal distribution of stresses and pressure in the human skull and brain. By detailing the results from a series of careful experiments and numerical simulations, this paper demonstrates that: (1) Geometry of the head governs the flow dynamics around the head which in turn determines the net mechanical load on the head. (2) Biomechanical loading of the brain is governed by direct wave transmission, structural deformations, and wave reflections from tissue-material interfaces. (3) Deformation and stress analysis of the skull and brain show that skull flexure and tissue cavitation are possible mechanisms of blast-induced traumatic brain injury.

  16. Determination of stimulation focality in heterogeneous head models during transcranial magnetic stimulation (TMS)

    Science.gov (United States)

    Lee, Erik; Hadimani, Ravi; Jiles, David

    2015-03-01

    Transcranial Magnetic Stimulation (TMS) is an increasingly popular tool used by both the scientific and medical community to understand and treat the brain. TMS has the potential to help people with a wide range of diseases such as Parkinson's, Alzheimer's, and PTSD, while currently being used to treat people with chronic, drug-resistant depression. Through computer simulations, we are able to see the electric field that TMS induces in anatomical human models, but there is no measure to quantify this electric field in a way that relates to a specific patient undergoing TMS therapy. We propose a way to quantify the focality of the induced electric field in a heterogeneous head model during TMS by relating the surface area of the brain being stimulated to the total volume of the brain being stimulated. This figure would be obtained by conducting finite element analysis (FEA) simulations of TMS therapy on a patient specific head model. Using this figure to assist in TMS therapy will allow clinicians and researchers to more accurately stimulate the desired region of a patient's brain and be more equipped to do comparative studies on the effects of TMS across different patients. This work was funded by the Carver Charitable Trust.

  17. Integrated Model of the Eye/Optic Nerve Head Biomechanical Environment

    Science.gov (United States)

    Ethier, C. R.; Feola, A.; Myers, J. G.; Nelson, E.; Raykin, J.; Samuels, B.

    2017-01-01

    Visual Impairment and Intracranial Pressure (VIIP) syndrome is a concern for long-duration space flight. Previously, it has been suggested that ocular changes observed in VIIP syndrome are related to the cephalad fluid shift that results in altered fluid pressures [1]. We are investigating the impact of changes in intracranial pressure (ICP) using a combination of numerical models, which simulate the effects of various environment conditions, including finite element (FE) models of the posterior eye. The specific interest is to understand how altered pressures due to gravitational changes affect the biomechanical environment of tissues of the posterior eye and optic nerve sheath. METHODS: Additional description of the numerical modeling is provided in the IWS abstract by Nelson et al. In brief, to simulate the effects of a cephalad fluid shift on the cardiovascular and ocular systems, we utilized a lumped-parameter compartment model of these systems. The outputs of this lumped-parameter model then inform boundary conditions (pressures) for a finite element model of the optic nerve head (Figure 1). As an example, we show here a simulation of postural change from supine to 15 degree head-down tilt (HDT), with primary outcomes being the predicted change in strains at the optic nerve head (ONH) region, specifically in the lamina cribrosa (LC), retrolaminar optic nerve, and prelaminar neural tissue (PLNT). The strain field can be decomposed into three orthogonal components, denoted as the first, second and third principal strains. We compare the peak tensile (first principal) and compressive (third principal) strains, since elevated strain alters cell phenotype and induces tissue remodeling. RESULTS AND CONCLUSIONS: Our lumped-parameter model predicted an IOP increase of c. 7 mmHg after 21 minutes of 15 degree HDT, which agreed with previous reports of IOP in HDT [1]. The corresponding FEM simulations predicted a relative increase in the magnitudes of the peak tensile

  18. Numerical Modeling of Scour at the Head of a Vertical-Wall Breakwater in Waves

    Science.gov (United States)

    Baykal, C.; Balcı, H. B.; Sumer, B. M.; Fuhrman, D. R.

    2017-12-01

    This study presents a 3D numerical modeling study on the flow and scour at the head of a vertical-wall breakwater in regular waves. The numerical model utilized in the study is based on that given by Jacobsen (2011). The present model has been applied successfully to the scour and backfilling beneath submarine pipelines by Fuhrman et al. (2014), and around a vertical cylindrical pile mounted on a horizontal plane sediment bed by Baykal et al. (2015, 2017). The model is composed of two main modules. The first module is the hydrodynamic model where Reynolds Averaged Navier Stokes (RANS) equations are solved with a k-ω turbulence closure. The second module is the morphologic model which comprises five sub-modules, namely; bed load, suspended load, sand slide, bed evolution and 3D mesh motion. The model is constructed in open-source CFD toolbox OpenFOAM. In this study, the model is applied to experimental data sets of Sumer and Fredsoe (1997) on the scour around a vertical-wall breakwater with a circular round head. Here, it is given the preliminary results of bed evolution of Test-8 of Sumer and Fredsoe (1997) in which a vertical-wall breakwater head with a width of B=140 mm is subjected to oscillatory flow with Tw=2.0 s and maximum orbital velocity at the bed Um=22cm/s, resulting in a Keulegan-Carpenter number, KC=3.14, close to KC experienced in real-life situations (KC = O(1)). The grain size is d=0.17 mm. The Shields parameter in the test case is given as θc=0.11, larger than the critical value for the initiation of motion implying that the scour is in the live-bed regime. The computational domain used in the simulations has the following dimensions: Length, l=40B, Width, w=20B, and Height, h=2B. The total number of cells is O(105) in the simulations. The scoured bed profile computed at the end of 3 periods of oscillatory flow of Test-8 is given in the figure below. The color scale in the figure is given for the ratio of bed elevation to the width of breakwater

  19. Study of the influence of the laterality of mobile phone use on the SAR induced in two head models

    Science.gov (United States)

    Ghanmi, Amal; Varsier, Nadège; Hadjem, Abdelhamid; Conil, Emmanuelle; Picon, Odile; Wiart, Joe

    2013-05-01

    The objective of this paper is to investigate and to analyse the influence of the laterality of mobile phone use on the exposure of the brain to radio-frequencies (RF) and electromagnetic fields (EMF) from different mobile phone models using the finite-difference time-domain (FDTD) method. The study focuses on the comparison of the specific absorption rate (SAR) induced on the right and left sides of two numerical adult and child head models. The heads are exposed by both phone models operating in GSM frequency bands for both ipsilateral and contralateral configurations. A slight SAR difference between the two sides of the heads is noted. The results show that the variation between the left and the right sides is more important at 1800 MHz for an ipsilateral use. Indeed, at this frequency, the variation can even reach 20% for the SAR10g and the SAR1g induced in the head and in the brain, respectively. Moreover, the average SAR induced by the mobile phone in the half hemisphere of the brain in ipsilateral exposure is higher than in contralateral exposure. Owing to the superficial character of energy deposition at 1800 MHz, this difference in the SAR induced for the ipsilateral and contralateral usages is more significant at 1800 MHz than at 900 MHz. The results have shown that depending on the phantom head models, the SAR distribution in the brain can vary because of differences in anatomical proportions and in the geometry of the head models. The induced SAR in child head and in sub-regions of the brain is significantly higher (up to 30%) compared to the adult head. This paper confirms also that the shape/design of the mobile and the location of the antenna can have a large influence at high frequency on the exposure of the brain, particularly on the SAR distribution and on the distinguished brain regions.

  20. Resistor mesh model of a spherical head: part 2: a review of applications to cortical mapping.

    Science.gov (United States)

    Chauveau, N; Morucci, J P; Franceries, X; Celsis, P; Rigaud, B

    2005-11-01

    A resistor mesh model (RMM) has been validated with reference to the analytical model by consideration of a set of four dipoles close to the cortex. The application of the RMM to scalp potential interpolation was detailed in Part 1. Using the RMM and the same four dipoles, the different methods of cortical mapping were compared and have shown the potentiality of this RMM for obtaining current and potential cortical distributions. The lead-field matrices are well-adapted tools, but the use of a square matrix of high dimension does not permit the inverse solution to be improved in the presence of noise, as a regularisation technique is necessary with noisy data. With the RMM, the transfer matrix and the cortical imaging technique proved to be easy to implement. Further development of the RMM will include application to more realistic head models with more accurate conductivities.

  1. Emu model of full-range femoral head osteonecrosis induced focally by an alternating freezing and heating insult.

    Science.gov (United States)

    Fan, M; Peng, J; Wang, A; Zhang, L; Liu, B; Ren, Z; Xu, W; Sun, J; Xu, Lx; Xiao, D; Qin, L; Lu, S; Wang, Y; Guo, Q Y

    2011-01-01

    The emu, a large bipedal bird with hip joint biomechanics similar to humans, was used to establish an experimental model of femoral head osteonecrosis and subsequent femoral head collapse. Focal lesions were induced in 20 adult male emus using an alternating liquid nitrogen freezing and radiofrequency heating insult. At 2, 4, 8, 12 and 16 weeks post-surgery, hip magnetic resonance imaging (MRI) was performed. Before the emus were sacrificed, barium sulphate was infused to the lower extremity to study blood vessel distribution patterns. Femoral samples were scanned by micro-computed tomography (micro-CT) and evaluated histologically. Hip MRI showed changes from broad oedema to femoral head collapse. Emus developed a crippled gait from post-operative week 6. Micro-CT scans and histology showed human-like osteonecrotic changes with an impaired local blood supply. The protocol resulted in consistent full-range osteonecrosis of the femoral head that may serve as a model for testing potential treatments.

  2. Probing culture in the head: the neural correlates of relational models.

    Science.gov (United States)

    Dien, Joseph; Karuzis, Valerie; Haarmann, Henk J

    2018-04-03

    Relational Models Theory or RMT proposes that there are four universal ways in which socio-economic relations can be organized. According to the RMT, each of its four relational models (Communal Sharing, Authority Ranking, Equality Matching, and Market Pricing) is associated with a distinct cognitive representation, with a cumulative pattern in which each relational model is a superset of the next lower model. This report for the first time uses a combination of cognitive and the social neuroscience to put this model to the test. RMT proposes that members of every culture use all four relational models, just in different proportions. It should therefore be possible to study their neural correlates in a mono-cultural sample. In this study, thirty-nine European-American students were imaged in a 3T Siemens Trio with a 24-channel head coil while rating the extent to which each relational model organized relationships with each of thirty-two acquaintances/friend/relatives in a boxcar design. FreeSurfer Functional Analysis Stream (FS-FAST) analyses revealed distinct patterns of activation for each of the relational models. The activations did not follow a cumulative hierarchical pattern, suggestive that this aspect of the RMT model should be revised.

  3. Statistical shape modelling to aid surgical planning: associations between surgical parameters and head shapes following spring-assisted cranioplasty.

    Science.gov (United States)

    Rodriguez-Florez, Naiara; Bruse, Jan L; Borghi, Alessandro; Vercruysse, Herman; Ong, Juling; James, Greg; Pennec, Xavier; Dunaway, David J; Jeelani, N U Owase; Schievano, Silvia

    2017-10-01

    Spring-assisted cranioplasty is performed to correct the long and narrow head shape of children with sagittal synostosis. Such corrective surgery involves osteotomies and the placement of spring-like distractors, which gradually expand to widen the skull until removal about 4 months later. Due to its dynamic nature, associations between surgical parameters and post-operative 3D head shape features are difficult to comprehend. The current study aimed at applying population-based statistical shape modelling to gain insight into how the choice of surgical parameters such as craniotomy size and spring positioning affects post-surgical head shape. Twenty consecutive patients with sagittal synostosis who underwent spring-assisted cranioplasty at Great Ormond Street Hospital for Children (London, UK) were prospectively recruited. Using a nonparametric statistical modelling technique based on mathematical currents, a 3D head shape template was computed from surface head scans of sagittal patients after spring removal. Partial least squares (PLS) regression was employed to quantify and visualise trends of localised head shape changes associated with the surgical parameters recorded during spring insertion: anterior-posterior and lateral craniotomy dimensions, anterior spring position and distance between anterior and posterior springs. Bivariate correlations between surgical parameters and corresponding PLS shape vectors demonstrated that anterior-posterior (Pearson's [Formula: see text]) and lateral craniotomy dimensions (Spearman's [Formula: see text]), as well as the position of the anterior spring ([Formula: see text]) and the distance between both springs ([Formula: see text]) on average had significant effects on head shapes at the time of spring removal. Such effects were visualised on 3D models. Population-based analysis of 3D post-operative medical images via computational statistical modelling tools allowed for detection of novel associations between surgical

  4. Solving the forward problem in EEG source analysis by spherical and fdm head modeling: a comparative analysis - biomed 2009

    NARCIS (Netherlands)

    Vatta, F.; Meneghini, F.; Esposito, F.; Mininel, S.; Di Salle, F.

    2009-01-01

    Neural source localization techniques based on electroencephalography (EEG) use scalp potential data to infer the location of underlying neural activity. This procedure entails modeling the sources of EEG activity and modeling the head volume conduction process to link the modeled sources to the

  5. Multistate models for estimation of survival and reproduction in the Grey-headed Albatross (Thalassarche chrysostoma)

    Science.gov (United States)

    Converse, Sarah J.; Kendall, William L.; Doherty, Paul F.; Ryan, Peter G.

    2009-01-01

    Reliable information on demography is necessary for conservation of albatrosses, the most threatened family of pelagic birds. Albatross survival has been estimated using mark-recapture data and the Cormack-Jolly-Seber (CJS) model. However, albatross exhibit skipped breeding, violating assumptions of the CJS model. Multistate modeling integrating unobservable states is a promising tool for such situations. We applied multistate models to data on Grey-headed Albatross (Talassarche chrysostoma) to evaluate model performance and describe demographic patterns. These included a multistate equivalent of the CJS model (MS-2), including successful and failed breeding states and ignoring temporary emigration, and three versions of a four-state multistate model that accounts for temporary emigration by integrating unobservable states: a model (MS-4) with one sample per breeding season, a robust design model (RDMS-4) with multiple samples per season and geographic closure within the season, and an open robust design model (ORDMS-4) with multiple samples per season and staggered entry and exit of animals within the season. Survival estimates from the MS-2 model were higher than those from the MS-4 model, which resulted in apparent percent relative bias averaging 2.2%. The ORDMS-4 model was more appropriate than the RDMS-4 model, given that staggered entry and exit occurred. Annual survival probability for Greyheaded Albatross at Marion Island was 0.951 ± 0.006 (SE), and the probability of skipped breeding in a subsequent year averaged 0.938 for successful and 0.163 for failed breeders. We recommend that multistate models with unobservable states, combined with robust-design sampling, be used in studies of species that exhibit temporary emigration.

  6. Estimation of electrical conductivity of a layered spherical head model using electrical impedance tomography

    Science.gov (United States)

    Fernández-Corazza, M.; von-Ellenrieder, N.; Muravchik, C. H.

    2011-12-01

    Electrical Impedance Tomography (EIT) is a non-invasive method that aims to create an electrical conductivity map of a volume. In particular, it can be applied to study the human head. The method consists on the injection of an unperceptive and known current through two electrodes attached to the scalp, and the measurement of the resulting electric potential distribution at an array of sensors also placed on the scalp. In this work, we propose a parametric estimation of the brain, scalp and skull conductivities using EIT over an spherical model of the head. The forward problem involves the computation of the electric potential on the surface, for given the conductivities and the injection electrode positions, while the inverse problem consists on estimating the conductivities given the sensor measurements. In this study, the analytical solution to the forward problem based on a three layer spherical model is first described. Then, some measurements are simulated adding white noise to the solutions and the inverse problem is solved in order to estimate the brain, skull and scalp conductivity relations. This is done with a least squares approach and the Nelder-Mead multidimensional unconstrained nonlinear minimization method.

  7. A Gaussian process regression model for walking speed estimation using a head-worn IMU.

    Science.gov (United States)

    Zihajehzadeh, Shaghayegh; Park, Edward J

    2017-07-01

    Miniature inertial sensors mainly worn on waist, ankle and wrist have been widely used to measure walking speed of the individuals for lifestyle and/or health monitoring. Recent emergence of head-worn inertial sensors in the form of a smart eyewear (e.g. Recon Jet) or a smart ear-worn device (e.g. Sensixa e-AR) provides an opportunity to use these sensors for estimation of walking speed in real-world environment. This work studies the feasibility of using a head-worn inertial sensor for estimation of walking speed. A combination of time-domain and frequency-domain features of tri-axial acceleration norm signal were used in a Gaussian process regression model to estimate walking speed. An experimental evaluation was performed on 15 healthy subjects during free walking trials in an indoor environment. The results show that the proposed method can provide accuracies of better than around 10% for various walking speed regimes. Additionally, further evaluation of the model for long (15-minutes) outdoor walking trials reveals high correlation of the estimated walking speed values to the ones obtained from fusion of GPS with inertial sensors.

  8. HYDROïD humanoid robot head with perception and emotion capabilities :Modeling, Design and Experimental Results

    Directory of Open Access Journals (Sweden)

    Samer eAlfayad

    2016-04-01

    Full Text Available In the framework of the HYDROïD humanoid robot project, this paper describes the modeling and design of an electrically actuated head mechanism. Perception and emotion capabilities are considered in the design process. Since HYDROïD humanoid robot is hydraulically actuated, the choice of electrical actuation for the head mechanism addressed in this paper is justified. Considering perception and emotion capabilities leads to a total number of 15 degrees of freedom for the head mechanism which are split on four main sub-mechanisms: the neck, the mouth, the eyes and the eyebrows. Biological data and kinematics performances of human head are taken as inputs of the design process. A new solution of uncoupled eyes is developed to possibly address the master-slave process that links the human eyes as well as vergence capabilities. Modeling each sub-system is carried out in order to get equations of motion, their frequency responses and their transfer functions. The neck pitch rotation is given as a study example. Then, the head mechanism performances are presented through a comparison between model and experimental results validating the hardware capabilities. Finally, the head mechanism is integrated on the HYDROïD upper-body. An object tracking experiment coupled with emotional expressions is carried out to validate the synchronization of the eye rotations with the body motions.

  9. Temperature elevation in the eye of anatomically based human head models for plane-wave exposures

    International Nuclear Information System (INIS)

    Hirata, A; Watanabe, S; Fujiwara, O; Kojima, M; Sasaki, K; Shiozawa, T

    2007-01-01

    This study investigated the temperature elevation in the eye of anatomically based human head models for plane-wave exposures. The finite-difference time-domain method is used for analyzing electromagnetic absorption and temperature elevation. The eyes in the anatomic models have average dimensions and weight. Computational results show that the ratio of maximum temperature in the lens to the eye-average SAR (named 'heating factor for the lens') is almost uniform (0.112-0.147 deg. C kg W -1 ) in the frequency region below 3 GHz. Above 3 GHz, this ratio increases gradually with an increase of frequency, which is attributed to the penetration depth of an electromagnetic wave. Particular attention is paid to the difference in the heating factor for the lens between this study and earlier works. Considering causes clarified in this study, compensated heating factors in all these studies are found to be in good agreement

  10. Dynamic head-neck stabilization and modulation with perturbation bandwidth investigated using a multisegment neuromuscular model

    NARCIS (Netherlands)

    Happee, R. (Riender); de Bruijn, E. (Edo); Forbes, P.A. (Patrick A.); F.C.T. van der Helm (Frans C.)

    2017-01-01

    textabstractThe human head-neck system requires continuous stabilization in the presence of gravity and trunk motion. We investigated contributions of the vestibulocollic reflex (VCR), the cervicocollic reflex (CCR), and neck muscle co-contraction to head-in-space and head-on-trunk stabilization,

  11. Dynamic head-neck stabilization and modulation with perturbation bandwidth investigated using a multisegment neuromuscular model

    NARCIS (Netherlands)

    Happee, R.; de Bruijn, E.; Forbes, P.A.; van der Helm, F.C.T.

    2017-01-01

    The human head-neck system requires continuous stabilization in the presence of gravity and trunk motion. We investigated contributions of the vestibulocollic reflex (VCR), the cervicocollic reflex (CCR), and neck muscle co-contraction to head-in-space and head-on-trunk stabilization, and

  12. MRI-Based Multiscale Model for Electromagnetic Analysis in the Human Head with Implanted DBS

    Directory of Open Access Journals (Sweden)

    Maria Ida Iacono

    2013-01-01

    Full Text Available Deep brain stimulation (DBS is an established procedure for the treatment of movement and affective disorders. Patients with DBS may benefit from magnetic resonance imaging (MRI to evaluate injuries or comorbidities. However, the MRI radio-frequency (RF energy may cause excessive tissue heating particularly near the electrode. This paper studies how the accuracy of numerical modeling of the RF field inside a DBS patient varies with spatial resolution and corresponding anatomical detail of the volume surrounding the electrodes. A multiscale model (MS was created by an atlas-based segmentation using a 1 mm3 head model (mRes refined in the basal ganglia by a 200 μm2 ex-vivo dataset. Four DBS electrodes targeting the left globus pallidus internus were modeled. Electromagnetic simulations at 128 MHz showed that the peak of the electric field of the MS doubled (18.7 kV/m versus 9.33 kV/m and shifted 6.4 mm compared to the mRes model. Additionally, the MS had a sixfold increase over the mRes model in peak-specific absorption rate (SAR of 43.9 kW/kg versus 7 kW/kg. The results suggest that submillimetric resolution and improved anatomical detail in the model may increase the accuracy of computed electric field and local SAR around the tip of the implant.

  13. The multi-modal responses of a physical head model subjected to various blast exposure conditions

    Science.gov (United States)

    Ouellet, S.; Phillippens, M.

    2017-11-01

    The local and global biomechanical response of the body to a blast wave is the first step of a sequence that leads to the development of stresses and strains which can exceed the tolerance of brain tissue. These stresses and strains may then lead to neuro-physical changes in the brain and contribute to initiate a cascade of events leading to injury. The specific biomechanical pathways by which the blast energy is transmitted through the head structure are, however, not clearly understood. Multiple transmission mechanisms have been proposed to explain the generation of brain stresses following the impingement of a blast wave on the head. With the use of a physical head model, the work presented here aims at demonstrating that the proposed transmission mechanisms are not mutually exclusive. They are part of a continuum of head responses where, depending on the exposure conditions, a given mechanism may or may not dominate. This article presents the joint analysis of previous blast test results generated with the brain injury protection evaluation device (BIPED) headform under four significantly different exposure conditions. The focus of the analysis is to demonstrate how the nature of the recorded response is highly dependent on the exposure characteristics and consequently, on the method used to reproduce blast exposure in a laboratory environment. The timing and magnitude of the variations in intra-cranial pressures (ICP) were analysed relative to the external pressure field in order to better understand the wave dynamics occurring within the brain structure of the headform. ICP waveforms were also analysed in terms of their energy spectral density to better identify the energy partitioning between the different modes of response. It is shown that the BIPED response is multi-modal and that the energy partitioning between its different modes of response is greatly influenced by exposure characteristics such as external peak overpressure, impulse, blast wave

  14. The multi-modal responses of a physical head model subjected to various blast exposure conditions

    Science.gov (United States)

    Ouellet, S.; Philippens, M.

    2018-01-01

    The local and global biomechanical response of the body to a blast wave is the first step of a sequence that leads to the development of stresses and strains which can exceed the tolerance of brain tissue. These stresses and strains may then lead to neuro-physical changes in the brain and contribute to initiate a cascade of events leading to injury. The specific biomechanical pathways by which the blast energy is transmitted through the head structure are, however, not clearly understood. Multiple transmission mechanisms have been proposed to explain the generation of brain stresses following the impingement of a blast wave on the head. With the use of a physical head model, the work presented here aims at demonstrating that the proposed transmission mechanisms are not mutually exclusive. They are part of a continuum of head responses where, depending on the exposure conditions, a given mechanism may or may not dominate. This article presents the joint analysis of previous blast test results generated with the brain injury protection evaluation device (BIPED) headform under four significantly different exposure conditions. The focus of the analysis is to demonstrate how the nature of the recorded response is highly dependent on the exposure characteristics and consequently, on the method used to reproduce blast exposure in a laboratory environment. The timing and magnitude of the variations in intra-cranial pressures (ICP) were analysed relative to the external pressure field in order to better understand the wave dynamics occurring within the brain structure of the headform. ICP waveforms were also analysed in terms of their energy spectral density to better identify the energy partitioning between the different modes of response. It is shown that the BIPED response is multi-modal and that the energy partitioning between its different modes of response is greatly influenced by exposure characteristics such as external peak overpressure, impulse, blast wave

  15. A TRACER 3D Co-Culture tumour model for head and neck cancer.

    Science.gov (United States)

    Young, Miki; Rodenhizer, Darren; Dean, Teresa; D'Arcangelo, Elisa; Xu, Bin; Ailles, Laurie; McGuigan, Alison P

    2018-05-01

    Cancer-associated fibroblasts (CAFs) are a key component of the tumour microenvironment and have been shown to play an important role in the progression of cancer. To probe these tumour-stroma interactions, we incorporated CAFs derived from head and neck cancer patients and squamous carcinoma cells of the hypopharynx (FaDu) into the Tissue Roll for the Analysis of Cellular Environment and Response (TRACER) platform to establish a co-culture platform that simulates the CAF-tumour microenvironmental interactions in head and neck tumours. TRACER culture involves infiltrating cells into a thin fibrous scaffold and then rolling the resulting biocomposite around a mandrel to generate a 3D and layered structure. Patterning the fibrous scaffold biocomposite during fabrication enables control over the specific location of different cell populations in the rolled configuration. Here, we optimized the seeding densities and configurations of the CAF and FaDu cell tissue sections to enable a robust 3D co-culture system under normoxic conditions. Co-culture of CAFs with FaDu cells produced negligible effects on radiation resistance, but did produce increases in proliferation rate and invasive cell migration at 24 and 48 h of culture. Our study provides the basis for use of our in vitro co-culture TRACER model to investigate the tumour-stroma interactions, and to bridge the translational gap between preclinical and clinical studies. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. A domestic porcine model for studying the effects of radiation on head and neck cancers.

    Science.gov (United States)

    Arnold, Christoph R; Kloss, Frank; Singh, Sarvpreet; Vasiljevic, Danijela; Stigler, Robert; Auberger, Thomas; Wenzel, Volker; Klima, Günter; Lukas, Peter; Lepperdinger, Günter; Gassner, Robert

    2017-05-01

    Radiation therapy (RT) of the head and neck region is often accompanied by serious side effects. Research in this area is needed to improve treatment outcomes and ameliorate therapy tolerance. Laboratory rodents are barely matching today's clinical standards in RT research. Yet domestic swine (Sus scrofa domestica) have previously proved suitable for various advanced tests in clinical research and training. We therefore investigated whether S. scrofa domestica is also appropriate for irradiation of the mandible. A common scheme for irradiation treatment of S. scrofa domestica mandibles in a split-mouth design was acquired by applying computed tomography (CT) scanning under sedation. Basing on close anatomic resemblance, a standard treatment plan comprising 2 opposed irradiation fields could be accomplished. RT was carried out in a clinical environment with 2 × 9 Gy. The resulting operating procedure facilitated complication-free sedation, transport, positioning, CT scanning, and effective irradiation. Based on common standards applied for RT in humans, domestic pigs can be employed to progress RT clinical research. Due to their human-like anatomy, physiology, size, and weight, the swine model is expedient for advancing experimental RT of the head and neck area. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Bioinformatic and statistical analysis of the optic nerve head in a primate model of ocular hypertension

    Directory of Open Access Journals (Sweden)

    Rasmussen Carol A

    2008-09-01

    Full Text Available Abstract Background The nonhuman primate model of glaucomatous optic neuropathy most faithfully reproduces the human disease. We used high-density oligonucleotide arrays to investigate whole genome transcriptional changes occurring at the optic nerve head during primate experimental glaucoma. Results Laser scarification of the trabecular meshwork of cynomolgus macaques produced elevated intraocular pressure that was monitored over time and led to varying degrees of damage in different samples. The macaques were examined clinically before enucleation and the myelinated optic nerves were processed post-mortem to determine the degree of neuronal loss. Global gene expression was examined in dissected optic nerve heads with Affymetrix GeneChip microarrays. We validated a subset of differentially expressed genes using qRT-PCR, immunohistochemistry, and immuno-enriched astrocytes from healthy and glaucomatous human donors. These genes have previously defined roles in axonal outgrowth, immune response, cell motility, neuroprotection, and extracellular matrix remodeling. Conclusion Our findings show that glaucoma is associated with increased expression of genes that mediate axonal outgrowth, immune response, cell motility, neuroprotection, and ECM remodeling. These studies also reveal that, as glaucoma progresses, retinal ganglion cell axons may make a regenerative attempt to restore lost nerve cell contact.

  18. Keefektifan Model Pembelajaran Number Head Together Berbantuan Metode Discovery terhadap Hasil Belajar Matematika

    Directory of Open Access Journals (Sweden)

    Ari Bintari

    2017-12-01

    Full Text Available Low mathematics learning outcomes and student activeness due to lack of effective learning model in optimizing students’ ability and motivation. The formulation of this research problem is whether the learning model Number Head Together (NHT with the help of effective discovery method to the result of student learning class III. This study aims to determine the effectiveness of the model with the help of the method of discovery of learning mathematics class III SDN Mewek. Pre-experimental method used in this research, which tests, documentation study, and observation sheet as its instruments. Based on the results of the final analysis that has been done visible from the percentage of mastery learning aiswa show learning without using learning model NHT as 5 students who completed with 25% percent and 15 students have not completed with the percentage 75%. Whereas after being given (posttest treatment using NHT learning model and pizza media fractions that complete 16 students with percentage 80% and 4 students have not completed with percentage 20%. It is reinforced by t-test, that students’ achievement has been increased significantly by NHT model.

  19. Effect of Anatomically Realistic Full-Head Model on Activation of Cortical Neurons in Subdural Cortical Stimulation—A Computational Study

    Science.gov (United States)

    Seo, Hyeon; Kim, Donghyeon; Jun, Sung Chan

    2016-06-01

    Electrical brain stimulation (EBS) is an emerging therapy for the treatment of neurological disorders, and computational modeling studies of EBS have been used to determine the optimal parameters for highly cost-effective electrotherapy. Recent notable growth in computing capability has enabled researchers to consider an anatomically realistic head model that represents the full head and complex geometry of the brain rather than the previous simplified partial head model (extruded slab) that represents only the precentral gyrus. In this work, subdural cortical stimulation (SuCS) was found to offer a better understanding of the differential activation of cortical neurons in the anatomically realistic full-head model than in the simplified partial-head models. We observed that layer 3 pyramidal neurons had comparable stimulation thresholds in both head models, while layer 5 pyramidal neurons showed a notable discrepancy between the models; in particular, layer 5 pyramidal neurons demonstrated asymmetry in the thresholds and action potential initiation sites in the anatomically realistic full-head model. Overall, the anatomically realistic full-head model may offer a better understanding of layer 5 pyramidal neuronal responses. Accordingly, the effects of using the realistic full-head model in SuCS are compelling in computational modeling studies, even though this modeling requires substantially more effort.

  20. Finite Element Model of the human head validated by the reconstruction of a real child sport accident

    Czech Academy of Sciences Publication Activity Database

    Brichtová, E.; Jiroušek, Ondřej; Gál, P.

    2009-01-01

    Roč. 82, č. 3 (2009), s. 175-180 ISSN 1211-3395 R&D Projects: GA ČR(CZ) GP103/07/P483 Institutional research plan: CEZ:AV0Z20710524 Keywords : paediatric brain injury * finite element models * head trauma * injury models Subject RIV: FH - Neurology

  1. A comparative analysis of reactor lower head debris cooling models employed in the existing severe accident analysis codes

    International Nuclear Information System (INIS)

    Ahn, K.I.; Kim, D.H.; Kim, S.B.; Kim, H.D.

    1998-08-01

    MELCOR and MAAP4 are the representative severe accident analysis codes which have been developed for the integral analysis of the phenomenological reactor lower head corium cooling behavior. Main objectives of the present study is to identify merits and disadvantages of each relevant model through the comparative analysis of the lower plenum corium cooling models employed in these two codes. The final results will be utilized for the development of LILAC phenomenological models and for the continuous improvement of the existing MELCOR reactor lower head models, which are currently being performed at the KAERI. For these purposes, first, nine reference models are selected featuring the lower head corium behavior based on the existing experimental evidences and related models. Then main features of the selected models have been critically analyzed, and finally merits and disadvantages of each corresponding model have been summarized in the view point of realistic corium behavior and reasonable modeling. Being on these evidences, summarized and presented the potential improvements for developing more advanced models. The present study has been focused on the qualitative comparison of each model and so more detailed quantitative analysis is strongly required to obtain the final conclusions for their merits and disadvantages. In addition, in order to compensate the limitations of the current model, required further studies relating closely the detailed mechanistic models with the molten material movement and heat transfer based on phase-change in the porous medium, to the existing simple models. (author). 36 refs

  2. Performance of a bulb turbine suitable for low prototype head: model test and transient numerical simulation

    Science.gov (United States)

    Zhu, L.; Zhang, H. P.; Zhang, J. G.; Meng, X. C.; Lu, L.

    2012-11-01

    In this paper, a bulb turbine, with unit specific speed of nq=223.1 min-1 suitable for low prototype head was studied from aspect of its performance. Hydraulic model of the turbine was developed firstly, and then model turbine was designed and manufactured. Performance tests were carried out on high-accuracy hydraulic machinery model universal test rig located at IWHR, including energy, cavitation and pressure fluctuation tests, etc. In order to investigate internal flow field, three-dimensional transient turbulence numerical simulation was conducted on the tested turbine, adopting Reynolds-averaged Navier-Stocks control equations and RNG k-ɛ turbulence model. Test and simulation results show that: (1) hydraulic efficiency of model turbine ηM is up to 91.7%, at the optimum operating point of n11o=165.54 r/min versus Q11o=1.93 m3/s; (2) numerical results agree well with experimental resultsby comparing pressure fluctuation, which shows that pressure amplitude is very low at the optimum operating point; (3) hydraulic loss in Outflow domain accounts for more than 50% total hydraulic loss due to flow separation and secondary flow.

  3. Calculation of electrical potentials on the surface of a realistic head model by finite differences

    International Nuclear Information System (INIS)

    Lemieux, L.; McBride, A.; Hand, J.W.

    1996-01-01

    We present a method for the calculation of electrical potentials at the surface of realistic head models from a point dipole generator based on a 3D finite-difference algorithm. The model was validated by comparing calculated values with those obtained algebraically for a three-shell spherical model. For a 1.25 mm cubic grid size, the mean error was 4.9% for a superficial dipole (3.75 mm from the inner surface of the skull) pointing in the radial direction. The effect of generator discretization and node spacing on the accuracy of the model was studied. Three values of the node spacing were considered: 1, 1.25 and 1.5 mm. The mean relative errors were 4.2, 6.3 and 9.3%, respectively. The quality of the approximation of a point dipole by an array of nodes in a spherical neighbourhood did not depend significantly on the number of nodes used. The application of the method to a conduction model derived from MRI data is demonstrated. (author)

  4. Electromagnetic Energy Deposition in a Concentric Spherical Model of the Human or Animal Head.

    Science.gov (United States)

    1979-12-01

    0.0355 0 0.0295 X< 0 . 0235 + 0.0175 At 0.01 15 MD 5-5)-10- Figure 8. Distrfbution of power density in a 10-cm-radius sphere, a model of the human head, at...34(1,4 i8(e 1 p)"(,)] (53) and 4p kp EO ti 2&+1 ~e,1) • (o,1) HP -- E o -) _[bo I Z T + T [ ( z ,p ) ’( I,t ) + a (t ,p ) ( Il , Il M( (e ,3 ) + (o ,3...observe that k 1 p (Cose) (!)1TE 0 !-B ,((d/de)P (cose)) + ij -,-e - + ((d/de)PI(cose)) + *A~t+p (Hcoe (tp) t(,) sine 35 and ( Hp ~ 4 k 00Pt,(Cose) ir 1E

  5. Quantitative Relationship between Axonal Injury and Mechanical Response in a Rodent Head Impact Acceleration Model

    Science.gov (United States)

    Li, Yan; Kallakuri, Srinivasu; Zhou, Runzhou; Cavanaugh, John M.

    2011-01-01

    Abstract A modified Marmarou impact acceleration model was developed to study the mechanical responses induced by this model and their correlation to traumatic axonal injury (TAI). Traumatic brain injury (TBI) was induced in 31 anesthetized male Sprague-Dawley rats (392±13 g) by a custom-made 450-g impactor from heights of 1.25 m or 2.25 m. An accelerometer and angular rate sensor measured the linear and angular responses of the head, while the impact event was captured by a high-speed video camera. TAI distribution along the rostro-caudal direction, as well as across the left and right hemispheres, was determined using β-amyloid precursor protein (β-APP) immunocytochemistry, and detailed TAI injury maps were constructed for the entire corpus callosum. Peak linear acceleration 1.25 m and 2.25 m impacts were 666±165 g and 907±501 g, respectively. Peak angular velocities were 95±24 rad/sec and 124±48 rad/sec, respectively. Compared to the 2.25-m group, the observed TAI counts in the 1.25-m impact group were significantly lower. Average linear acceleration, peak angular velocity, average angular acceleration, and surface righting time were also significantly different between the two groups. A positive correlation was observed between normalized total TAI counts and average linear acceleration (R2=0.612, pacceleration response of the rat head during impact, not necessarily the drop height. PMID:21895482

  6. An ex vivo model in human femoral heads for histopathological study and resonance frequency analysis of dental implant primary stability.

    Science.gov (United States)

    Hernández-Cortés, Pedro; Monje, Alberto; Galindo-Moreno, Pablo; Catena, Andrés; Ortega-Oller, Inmaculada; Salas-Pérez, José; Mesa, Francisco; Gómez-Sánchez, Rafael; Aguilar, Mariano; Aguilar, David; O'Valle, Francisco

    2014-01-01

    This study was designed to explore relationships of resonance frequency analysis (RFA)-assessed implant stability (ISQ values) with bone morphometric parameters and bone quality in an ex vivo model of dental implants placed in human femoral heads and to evaluate the usefulness of this model for dental implant studies. This ex vivo study included femoral heads from 17 patients undergoing surgery for femoral neck fracture due to osteoporosis (OP) (n = 7) or for total prosthesis joint replacement due to severe hip osteoarthrosis (OA) (n = 10). Sixty 4.5 × 13 mm Dentsply Astra implants were placed, followed by RFA. CD44 immunohistochemical analysis for osteocytes was also carried out. As expected, the analysis yielded significant effects of femoral head type (OA versus OA) (P implants (P = 0.455) or of the interaction of the two factors (P = 0.848). Bonferroni post hoc comparisons showed a lower mean ISQ for implants in decalcified (50.33 ± 2.92) heads than in fresh (66.93 ± 1.10) or fixated (70.77 ± 1.32) heads (both P 0.5 in all cases), and no significant differences in ISQ values were found as a function of the length or area of the cortical layer (both P > 0.08). Although RFA-determined ISQ values are not correlated with morphometric parameters, they can discriminate bone quality (OP versus OA). This ex vivo model is useful for dental implant studies.

  7. A poroelastic model for the perfusion of the lamina cribrosa in the optic nerve head.

    Science.gov (United States)

    Causin, Paola; Guidoboni, Giovanna; Harris, Alon; Prada, Daniele; Sacco, Riccardo; Terragni, Samuele

    2014-11-01

    In this work we present a mathematical model for the coupling between biomechanics and hemodynamics in the lamina cribrosa, a thin porous tissue at the base of the optic nerve head which is thought to be the site of injury in ocular neurodegenerative diseases such as glaucoma. In this exploratory two-dimensional investigation, the lamina cribrosa is modeled as a poroelastic material where blood vessels are viewed as pores in a solid elastic matrix. The model is used to investigate the influence on the distributions of stress, blood volume fraction (or vascular porosity) and blood velocity within the lamina cribrosa due to the application of different levels of the intraocular pressure (IOP) and the enforcement of different mechanical constraints at the lamina's boundary. The model simulations suggest that the degree of fixity of the boundary constraint strongly influences the lamina's response to IOP elevation. Specifically, when the boundary is mechanically clamped, IOP elevation leads to an increase in stress close to the lamina's boundary, making it more susceptible to tissue damage. On the other hand, when rotations are allowed at the boundary, the most vulnerable region appears to be located at the lamina's central axis, in proximity of the eye globe, where increased stress and reduced vascular porosity and blood velocity are predicted for increased levels of IOP. Published by Elsevier Inc.

  8. Nanoimmunoassay to Detect Responses in Head and Neck Cancer: Feasibility in a Mouse Model.

    Science.gov (United States)

    Hubbard, Matthew A; Khalil, Ashraf A; Schoeff, Stephen S; Allak, Amir; VanKoevering, Kyle K; Maxwell, Anne K; Adejumo, Oluwayemisi; Mendez, Rolando E; Jameson, Mark J

    2014-07-01

    To demonstrate the feasibility of detecting and quantifying extracellular signal-related kinase (ERK) phosphorylation status using nanoimmunoassay (NIA). Analyses using Cal27, SCC25, and OSC19 head and neck squamous carcinoma cell lines in vitro and in a murine xenograft model. NIA and immunoblot were performed on whole-cell lysates, tumor lysates, and fine-needle aspirate biopsies to detect ERK phosphorylation states. Using NIA, all 6 isoforms of ERK1/2, including nonphosphorylated, monophosphorylated, and diphosphorylated species, could be reliably detected, distinguished, and quantified in a single assay using a single antibody. In vitro treatment of Cal27 cells with the epidermal growth factor receptor inhibitor gefitinib abolished phospho-ERK detection by immunoblot but resulted in residual detectable species by NIA. Residual phospho-ERK in gefitinib-treated cells could be further reduced by the addition of the insulin-like growth factor 1 receptor inhibitor OSI-906; this correlated with an additional decrease in proliferation over gefitinib alone. In a pilot study of 4 murine xenograft tumors, NIA performed on tumor lysates and fine-needle aspirate biopsies demonstrated altered ERK profiles after 2 days of gefitinib treatment compared with untreated mice. NIA offers a novel approach to quantitating the activation state of signaling molecules such as ERK in nanoscale in vitro and in vivo samples across a wide dynamic range. As such, it has potential to provide molecular diagnostic information before, during, and after treatment using a minimally invasive technique. Further study is warranted to determine its utility in assessing signaling proteins as biomolecular outcome predictors in clinical trials. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2014.

  9. SCDAP/RELAP5 modeling of heat transfer and flow losses in lower head porous debris. Rev. 1

    International Nuclear Information System (INIS)

    Siefken, L.J.; Coryell, E.W.; Paik, S.; Kuo, H.

    1999-01-01

    Designs are described for implementing models for calculating the heat transfer and flow losses in porous debris in the lower head of a reactor vessel. The COUPLE model in SCDAP/RELAP5 represents both the porous and nonporous debris that results from core material slumping into the lower head. Currently, the COUPLE model has the capability to model convective and radiative heat transfer from the surfaces of nonporous debris in a detailed manner and to model only in a simplistic manner the heat transfer from porous debris. In order to advance beyond the simplistic modeling for porous debris, designs are developed for detailed calculations of heat transfer and flow losses in porous debris. Correlations are identified for convective heat transfer in porous debris for the following modes of heat transfer; (1) forced convection to liquid, (2) forced convection to gas, (3) nucleate boiling, (4) transition boiling, and (5) film boiling. Interphase heat transfer is modeled in an approximate ma nner. Designs are described for models to calculate the flow losses and interphase drag of fluid flowing through the interstices of the porous debris, and to apply these variables in the momentum equations in the RELAP5 part of the code. Since the models for heat transfer and flow losses in porous debris in the lower head are designed for general application, a design is also described for implementation of these models to the analysis of porous debris in the core region. A test matrix is proposed for assessing the capability of the implemented models to calculate the heat transfer and flow losses in porous debris. The implementation of the models described in this report is expected to improve the COUPLE code calculation of the temperature distribution in porous debris and in the lower head that supports the debris. The implementation of these models is also expected to improve the calculation of the temperature and flow distribution in porous debris in the core region

  10. Trunnion-Head Stresses in THA: Are Big Heads Trouble?

    Science.gov (United States)

    Lavernia, Carlos J; Iacobelli, David A; Villa, Jesus M; Jones, Kinzy; Gonzalez, Jose L; Jones, William Kinzy

    2015-06-01

    The effects of large heads on stresses at the THA trunnion-head junction and their impact on tribocorrosion/metal ion release remain controversial. A 12/14 3D-model of a stem with different head sizes was investigated. Material properties of titanium were assigned to the trunnion and cobalt-chrome/alumina to the heads. A load simulating walking single-leg stand phase was applied to the head. A total contact head-trunnion interface was assumed. The area underneath the junction underwent significant elevations in stresses as head size increased from 28- to 40-mm. Maximum principal stress doubled between 28 and 40-mm heads, regardless of head material. Stress levels had a direct correlation to head diameter. Stress increases observed using increasingly larger heads will probably contribute to head-trunnion tribocorrosion and ion release. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Brain response to primary blast wave using validated finite element models of human head and advanced combat helmet

    Directory of Open Access Journals (Sweden)

    Liying eZhang

    2013-08-01

    Full Text Available Blast-induced traumatic brain injury has emerged as a signature injury in combat casualty care. Present combat helmets are designed primarily to protect against ballistic and blunt impacts, but the current issue with helmets is protection concerning blasts. In order to delineate the blast wave attenuating capability of the Advanced Combat Helmet (ACH, a finite element (FE study was undertaken to evaluate the head response against blast loadings with and without helmet using a partially validated FE model of the human head and ACH. Four levels of overpressures (0.27-0.66 MPa from the Bowen’s lung iso-damage threshold curves were used to simulate blast insults. Effectiveness of the helmet with respect to head orientation was also investigated. The resulting biomechanical responses of the brain to blast threats were compared for human head with and without the helmet. For all Bowen’s cases, the peak intracranial pressures (ICP in the head ranged from 0.68-1.8 MPa in the coup cortical region. ACH was found to mitigate ICP in the head by 10-35%. Helmeted head resulted in 30% lower average peak brain strains and product of strain and strain rate. Among three blast loading directions with ACH, highest reduction in peak ICP (44% was due to backward blasts whereas the lowest reduction in peak ICP and brain strains was due to forward blast (27%. The biomechanical responses of a human head to primary blast insult exhibited directional sensitivity owing to the different geometry contours and coverage of the helmet construction and asymmetric anatomy of the head. Thus, direction-specific tolerances are needed in helmet design in order to offer omni-directional protection for the human head. The blasts of varying peak overpressures and durations that are believed to produce the same level of lung injury produce different levels of mechanical responses in the brain, and hence "iso-damage" curves for brain injury are likely different than the Bowen curves

  12. Implementation of a gust front head collapse scheme in the WRF numerical model

    Science.gov (United States)

    Lompar, Miloš; Ćurić, Mladjen; Romanic, Djordje

    2018-05-01

    Gust fronts are thunderstorm-related phenomena usually associated with severe winds which are of great importance in theoretical meteorology, weather forecasting, cloud dynamics and precipitation, and wind engineering. An important feature of gust fronts demonstrated through both theoretical and observational studies is the periodic collapse and rebuild of the gust front head. This cyclic behavior of gust fronts results in periodic forcing of vertical velocity ahead of the parent thunderstorm, which consequently influences the storm dynamics and microphysics. This paper introduces the first gust front pulsation parameterization scheme in the WRF-ARW model (Weather Research and Forecasting-Advanced Research WRF). The influence of this new scheme on model performances is tested through investigation of the characteristics of an idealized supercell cumulonimbus cloud, as well as studying a real case of thunderstorms above the United Arab Emirates. In the ideal case, WRF with the gust front scheme produced more precipitation and showed different time evolution of mixing ratios of cloud water and rain, whereas the mixing ratios of ice and graupel are almost unchanged when compared to the default WRF run without the parameterization of gust front pulsation. The included parameterization did not disturb the general characteristics of thunderstorm cloud, such as the location of updraft and downdrafts, and the overall shape of the cloud. New cloud cells in front of the parent thunderstorm are also evident in both ideal and real cases due to the included forcing of vertical velocity caused by the periodic collapse of the gust front head. Despite some differences between the two WRF simulations and satellite observations, the inclusion of the gust front parameterization scheme produced more cumuliform clouds and seem to match better with real observations. Both WRF simulations gave poor results when it comes to matching the maximum composite radar reflectivity from radar

  13. Cardiovascular models of simulated moon and mars gravities: head-up tilt vs. lower body unweighting.

    Science.gov (United States)

    Kostas, Vladimir I; Stenger, Michael B; Knapp, Charles F; Shapiro, Robert; Wang, Siqi; Diedrich, André; Evans, Joyce M

    2014-04-01

    In this study we compare two models [head-up tilt (HUT) vs. body unweighting using lower body positive pressure (LBPP)] to simulate Moon, Mars, and Earth gravities. A literature search did not reveal any comparisons of this type performed previously. We hypothesized that segmental fluid volume shifts (thorax, abdomen, upper and lower leg), cardiac output, and blood pressure (BP), heart rate (HR), and total peripheral resistance to standing would be similar in the LBPP and HUT models. There were 21 subjects who were studied while supine (simulation of spaceflight) and standing at 100% (Earth), 40% (Mars), and 20% (Moon) bodyweight produced by LBPP in Alter-G and while supine and tilted at 80 degrees, 20 degrees, and 10 degrees HUT (analogues of Earth, Mars, and Moon gravities, respectively). Compared to supine, fluid shifts from the chest to the abdomen, increases in HR, and decreases in stroke volume were greater at 100% bodyweight than at reduced weights in response to both LBPP and HUT. Differences between the two models were found for systolic BP, diastolic BP, mean arterial BP, stroke volume, total peripheral resistance, and thorax and abdomen impedances, while HR, cardiac output, and upper and lower leg impedances were similar. Bodyweight unloading via both LBPP and HUT resulted in cardiovascular changes similar to those anticipated in actual reduced gravity environments. The LBPP model/Alter-G has the advantage of providing an environment that allows dynamic activity at reduced bodyweight; however, the significant increase in blood pressures in the Alter-GC may favor the HUT model.

  14. SU-C-BRF-03: PCA Modeling of Anatomical Changes During Head and Neck Radiation Therapy

    International Nuclear Information System (INIS)

    Chetvertkov, M; Kim, J; Siddiqui, F; Kumarasiri, A; Chetty, I; Gordon, J

    2014-01-01

    Purpose: To develop principal component analysis (PCA) models from daily cone beam CTs (CBCTs) of head and neck (H and N) patients that could be used prospectively in adaptive radiation therapy (ART). Methods: : For 7 H and N patients, Pinnacle Treatment Planning System (Philips Healthcare) was used to retrospectively deformably register daily CBCTs to the planning CT. The number N of CBCTs per treatment course ranged from 14 to 22. For each patient a PCA model was built from the deformation vector fields (DVFs), after first subtracting the mean DVF, producing N eigen-DVFs (EDVFs). It was hypothesized that EDVFs with large eigenvalues represent the major anatomical deformations during the course of treatment, and that it is feasible to relate each EDVF to a clinically meaningful systematic or random change in anatomy, such as weight loss, neck flexion, etc. Results: DVFs contained on the order of 3×87×87×58=1.3 million scalar values (3 times the number of voxels in the registered volume). The top 3 eigenvalues accounted for ∼90% of variance. Anatomical changes corresponding to an EDVF were evaluated by generating a synthetic DVF, and applying that DVF to the CT to produce a synthetic CBCT. For all patients, the EDVF for the largest eigenvalue was interpreted to model weight loss. The EDVF for other eigenvalues appeared to represented quasi-random fraction-to-fraction changes. Conclusion: The leading EDVFs from single-patient PCA models have tentatively been identified with weight loss changes during treatment. Other EDVFs are tentatively identified as quasi-random inter-fraction changes. Clean separation of systematic and random components may require further work. This work is expected to facilitate development of population-based PCA models that can be used to prospectively identify significant anatomical changes, such as weight loss, early in treatment, triggering replanning where beneficial

  15. Feasibility of Primary Tumor Culture Models and Preclinical Prediction Assays for Head and Neck Cancer: A Narrative Review

    NARCIS (Netherlands)

    Dohmen, Amy J. C.; Swartz, Justin E.; van den Brekel, Michiel W. M.; Willems, Stefan M.; Spijker, René; Neefjes, Jacques; Zuur, Charlotte L.

    2015-01-01

    Primary human tumor culture models allow for individualized drug sensitivity testing and are therefore a promising technique to achieve personalized treatment for cancer patients. This would especially be of interest for patients with advanced stage head and neck cancer. They are extensively treated

  16. On numerical modeling of low-head direct chill ingot caster for magnesium alloy AZ31

    Directory of Open Access Journals (Sweden)

    Mainul Hasan

    2014-12-01

    Full Text Available A comprehensive 3D turbulent CFD study has been carried out to simulate a Low-Head (LH vertical Direct Chill (DC rolling ingot caster for the common magnesium alloy AZ31. The model used in this study takes into account the coupled laminar/turbulent melt flow and solidification aspects of the process and is based on the control-volume finite-difference approach. Following the aluminum/magnesium DC casting industrial practices, the LH mold is taken as 30 mm with a hot top of 60 mm. The previously verified in-house code has been modified to model the present casting process. Important quantitative results are obtained for four casting speeds, for three inlet melt pouring temperatures (superheats and for three metal-mold contact heat transfer coefficients for the steady state operational phase of the caster. The variable cooling water temperatures reported by the industry are considered for the primary and secondary cooling zones during the simulations. Specifically, the temperature and velocity fields, sump depth and sump profiles, mushy region thickness, solid shell thickness at the exit of the mold and axial temperature profiles at the center and at three strategic locations at the surface of the slab are presented and discussed.

  17. Early magnetic resonance imaging and histologic findings in a model of avascular necrosis of femoral head

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Takuya [Kanazawa Univ. (Japan). School of Medicine

    1997-12-01

    The present study was performed to examine early MR images and histologic findings using a canine model of avascular necrosis of femoral head (ANFH). The ANFH model was surgically induced. At three days, 1, 2 and 4 weeks after surgery, the proximal femurs were excised. MR images were obtained in 4 dogs at 3 days and 7 dogs at each of the other intervals. Histologic examinations were performed on 7 dogs at each interval. Three days after surgery, MR showed almost no abnormal findings. Histologic changes included edematous bone marrow and bleeding in the bone marrow in some regions. One week after surgery, empty lacunae in trabecular bones and immature fibrous tissues in the bone marrow were seen in some cases, but appositional bone was not yet apparent. In only one case, abnormal MR findings -a ringlike pattern- were seen. Two weeks after surgery, 4 cases showed appositional bones on histology and abnormalities on MR images. Four weeks after surgery, fibrous tissues had matured and appositional bones had increased. Therefore, all 7 cases showed MR imaging abnormalities. Abnormal MR images included a ringlike pattern, and homogeneous and inhomogeneous patterns. These results indicated that MR imaging shows abnormality 2 weeks after surgery at the latest. (author)

  18. Establishment of a head injury by club model in rabbits and experimental conditions

    International Nuclear Information System (INIS)

    Cao Yunxing; Xi Huanjiu; Zhang Jing; Li Hongwei; Yin Zhiyong; Zhao Hui

    2013-01-01

    Objective: To establish an animal model to replicate the injury by club in forensic medicine. Methods: Twenty-four New Zealand white rabbits were divided into control group (n=4), minor injury group (n=10), and severe injury group (n=10). Based on the BIM-Ⅱ Horizontal Bio-impact Machine, a self-designed iron bar was used to produce head injury by club. Six hours after injury, all the rabbits were subjected to a CT examination and dissected to observe the injury morphology and undergo routine pathological examination. Four control, six minor and severe rabbits were given moisture content examination. Results: Varying degrees of positive signs of the nervous system were observed in all the injured rabbits within 6 hours. The mortality rate was 1/10 in the minor injury group and 6/10 in the severe injury group. The morphological changes consisted of different levels of scalp hematoma, skull fracture, epidural hematoma, subdural hematoma, subarachnoid hemorrhage and brain injury. The difference in moisture content between the three groups was of statistical significance. Conclusion: Under the rigidly-controlled experimental condition, this animal model produces good reproducibility and stable results. Meanwhile, it can simulate the morphology of injury by club and be used to study the mechanism of injury by club in forensic medicine. (authors)

  19. Head Lice

    Science.gov (United States)

    Head lice are parasitic wingless insects. They live on people's heads and feed on their blood. An adult louse ... Children ages 3-11 and their families get head lice most often. Personal hygiene has nothing to ...

  20. Applying DTI white matter orientations to finite element head models to examine diffuse TBI under high rotational accelerations.

    LENUS (Irish Health Repository)

    Colgan, Niall C

    2010-12-01

    The in-vivo mechanical response of neural tissue during impact loading of the head is simulated using geometrically accurate finite element (FE) head models. However, current FE models do not account for the anisotropic elastic material behaviour of brain tissue. In soft biological tissue, there is a correlation between internal microscopic structure and macroscopic mechanical properties. Therefore, constitutive equations are important for the numerical analysis of the soft biological tissues. By exploiting diffusion tensor techniques the anisotropic orientation of neural tissue is incorporated into a non-linear viscoelastic material model for brain tissue and implemented in an explicit FE analysis. The viscoelastic material parameters are derived from published data and the viscoelastic model is used to describe the mechanical response of brain tissue. The model is formulated in terms of a large strain viscoelastic framework and considers non-linear viscous deformations in combination with non-linear elastic behaviour. The constitutive model was applied in the University College Dublin brain trauma model (UCDBTM) (i.e. three-dimensional finite element head model) to predict the mechanical response of the intra-cranial contents due to rotational injury.

  1. Head-Down Tilt with Balanced Traction as a Model for Simulating Spinal Acclimation to Microgravity

    Science.gov (United States)

    Ballard, R. E.; Styf, J. R.; Watenpaugh, D. E.; Fechner, K.; Haruna, Y.; Kahan, N. J.; Hargens, A. R.

    1994-01-01

    Astronauts experience total body height increases of 4 to 7 cm in microgravity. Thus, stretching of the spinal cord, nerve roots, and muscular and ligamentous tissues may be responsible for the hyperreflexia, back pain, and muscular atrophy associated with exposure to microgravity. Axial compression of the spine makes 6 deg. head-down tilt (HDT) an unsuitable model for spinal acclimation to microgravity. However, this axial compression may be counteracted by balanced traction consisting of 10% body weight (sin 6 deg. = 0.1) applied to the legs. Six healthy male subjects underwent 3 days each of 60 HDT with balanced traction and horizontal bed rest (HBR), with a 2 week recovery period between treatments. Total body and spine length, lumbar disc height, back pain, erector spinae intramuscular pressure, and ankle joint torque were measured before, during and after each treatment. Total body and spine (processes of L5 - C7) lengths increased significantly more during HDT with balanced traction (22 +/- 8 mm and 25 +/- 8 mm, respectively) than during HBR (16 +/- 4 mm and 14 +/- 9 mm, respectively). Back and leg pain were significantly greater during HDT with balanced traction than during HBR. The distance between the lower end plate of L4 and the upper endplate of S1, as measured by sonography, increased significantly in both treatments to the same degree (2.9 +/- 1.9 mm, HDT with balanced traction; 3.3 +/- 1.5 mm, HBR). Intramuscular pressure of the erector spinae muscles and maximal ankle joint torque were unaltered with both models. While neither model increased height to the magnitude observed in microgravity, HDT with balanced traction may be a better model for simulating the body lengthening and back pain experienced in microgravity.

  2. Image-based modeling of tumor shrinkage in head and neck radiation therapy

    International Nuclear Information System (INIS)

    Chao Ming; Xie Yaoqin; Moros, Eduardo G.; Le, Quynh-Thu; Xing Lei

    2010-01-01

    Purpose: Understanding the kinetics of tumor growth/shrinkage represents a critical step in quantitative assessment of therapeutics and realization of adaptive radiation therapy. This article presents a novel framework for image-based modeling of tumor change and demonstrates its performance with synthetic images and clinical cases. Methods: Due to significant tumor tissue content changes, similarity-based models are not suitable for describing the process of tumor volume changes. Under the hypothesis that tissue features in a tumor volume or at the boundary region are partially preserved, the kinetic change was modeled in two steps: (1) Autodetection of homologous tissue features shared by two input images using the scale invariance feature transformation (SIFT) method; and (2) establishment of a voxel-to-voxel correspondence between the images for the remaining spatial points by interpolation. The correctness of the tissue feature correspondence was assured by a bidirectional association procedure, where SIFT features were mapped from template to target images and reversely. A series of digital phantom experiments and five head and neck clinical cases were used to assess the performance of the proposed technique. Results: The proposed technique can faithfully identify the known changes introduced when constructing the digital phantoms. The subsequent feature-guided thin plate spline calculation reproduced the ''ground truth'' with accuracy better than 1.5 mm. For the clinical cases, the new algorithm worked reliably for a volume change as large as 30%. Conclusions: An image-based tumor kinetic algorithm was developed to model the tumor response to radiation therapy. The technique provides a practical framework for future application in adaptive radiation therapy.

  3. Barriers to generating PDX models of HPV-related head and neck cancer.

    Science.gov (United States)

    Facompre, Nicole D; Sahu, Varun; Montone, Kathleen T; Harmeyer, Kayla M; Nakagawa, Hiroshi; Rustgi, Anil K; Weinstein, Gregory S; Gimotty, Phyllis A; Basu, Devraj

    2017-12-01

    Delineate factors impacting the creation and use of patient-derived xenografts (PDXs) of human papilloma virus-related (HPV+) head and neck squamous cell carcinomas (HNSCCs). Laboratory-based translational study. Fifty-one surgically resected HNSCCs, including 31 HPV + cancers, were implanted into NOD/SCID/IL-2Rγ -/- (NSG) mice using standardized methodology. Clinical and pathologic factors were tested for association with engraftment. The gross, histologic, and molecular features of established HPV + PDXs were analyzed in comparison to their tumors of origin. Negative HPV status and perineural invasion (PNI) were independent, additive factors associated with increased PDX formation. Epstein-Barr virus-positive (EBV+) human large B-cell lymphomas grew from 32% of HPV + HNSCC cases that failed to engraft. Successfully established HPV + PDXs retained basaloid histology and often developed cystic growth patterns typical of HPV + nodal metastases. They also maintained elevated p16 INK4A levels and expression of E6/E7 viral oncogene transcripts. Reduced engraftment by HPV + tumors lacking PNI likely results in selection biases in HNSCC PDX models. Formation of EBV + lymphomas in NSG mice further reduces the generation of HPV + models and must be ruled out before long-term use of PDXs. Nevertheless, the retention of distinctive pathologic traits and viral oncogene expression by HPV + PDXs provides a viable in vivo platform for basic and translational studies as well as a resource for generating advanced in vitro models. NA. Laryngoscope, 127:2777-2783, 2017. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

  4. Modelling soil erosion in a head catchment of Jemma Basin on the Ethiopian highlands

    Science.gov (United States)

    Cama, Mariaelena; Schillaci, Calogero; Kropáček, Jan; Hochschild, Volker; Maerker, Michael

    2017-04-01

    Soil erosion represents one of the most important global issues with serious effects on agriculture and water quality especially in developing countries such as Ethiopia where rapid population growth and climatic changes affect wide mountainous areas. The catchment of Andit-Tid is a head catchment of Jemma Basin draining to the Blue Nile (Central Ethiopia). It is located in an extremely variable topographical environment and it is exposed to high degradation dynamics especially in the lower part of the catchment. The increasing agricultural activity and grazing, lead to an intense use of the steep slopes which altered the soil structure. As a consequence, water erosion processes accelerated leading to the evolution of sheet erosion, gullies and badlands. This study is aimed at a geomorphological assessment of soil erosion susceptibility. First, a geomorphological map is generated using high resolution digital elevation model (DEM) derived from high resolution stereoscopic satellite data, multispectral imagery from Rapid Eye satellite system . The map was then validated by a detailed field survey. The final maps contains three inventories of landforms: i) sheet, ii) gully erosion and iii) badlands. The water erosion susceptibility is calculated with a Maximum Entropy approach. In particular, three different models are built using the three inventories as dependent variables and a set of spatial attributes describing the lithology, terrain, vegetation and land cover from remote sensing data and DEMs as independent variables. The single susceptibility maps for sheet, gully erosion as well as badlands showed good to excellent predictive performances. Moreover, we reveal and discuss the importance of different sets of variables among the three models. In order to explore the mutual overlap of the three susceptibility maps we generated a combined map as color composite whereas each color represents one component of water erosion. The latter map yield a useful information

  5. Stimulation strength and focality of electroconvulsive therapy and magnetic seizure therapy in a realistic head model.

    Science.gov (United States)

    Lee, Won Hee; Lisanby, Sarah H; Laine, Andrew F; Peterchev, Angel V

    2014-01-01

    This study examines the characteristics of the electric field (E-field) induced in the brain by electroconvulsive therapy (ECT) and magnetic seizure therapy (MST). The electric field induced by five ECT electrode configurations (bilateral, bifrontal, right unilateral, focal electrically administered seizure therapy, and frontomedial) as well as an MST coil configuration (circular) was computed in an anatomically realistic finite element model of the human head. We computed the maps of the electric field strength relative to an estimated neural activation threshold, and used them to evaluate the stimulation strength and focality of the various ECT and MST paradigms. The results show that the median ECT stimulation strength in the brain is 3-11 times higher than that for MST, and that the stimulated brain volume is substantially higher with ECT (47-100%) than with MST (21%). Our study provides insight into the observed reduction of cognitive side effects in MST compared to ECT, and supports arguments for lowering ECT current amplitude as a means of curbing its side effects.

  6. Raman laser spectrometer optical head: qualification model assembly and integration verification

    Science.gov (United States)

    Ramos, G.; Sanz-Palomino, M.; Moral, A. G.; Canora, C. P.; Belenguer, T.; Canchal, R.; Prieto, J. A. R.; Santiago, A.; Gordillo, C.; Escribano, D.; Lopez-Reyes, G.; Rull, F.

    2017-08-01

    Raman Laser Spectrometer (RLS) is the Pasteur Payload instrument of the ExoMars mission, within the ESA's Aurora Exploration Programme, that will perform for the first time in an out planetary mission Raman spectroscopy. RLS is composed by SPU (Spectrometer Unit), iOH (Internal Optical Head), and ICEU (Instrument Control and Excitation Unit). iOH focuses the excitation laser on the samples (excitation path), and collects the Raman emission from the sample (collection path, composed on collimation system and filtering system). Its original design presented a high laser trace reaching to the detector, and although a certain level of laser trace was required for calibration purposes, the high level degrades the Signal to Noise Ratio confounding some Raman peaks. So, after the bread board campaign, some light design modifications were implemented in order to fix the desired amount of laser trace, and after the fabrication and the commitment of the commercial elements, the assembly and integration verification process was carried out. A brief description of the iOH design update for the engineering and qualification model (iOH EQM) as well as the assembly process are briefly described in this papers. In addition, the integration verification and the first functional tests, carried out with the RLS calibration target (CT), results are reported on.

  7. Concussion, microvascular injury, and early tauopathy in young athletes after impact head injury and an impact concussion mouse model.

    Science.gov (United States)

    Tagge, Chad A; Fisher, Andrew M; Minaeva, Olga V; Gaudreau-Balderrama, Amanda; Moncaster, Juliet A; Zhang, Xiao-Lei; Wojnarowicz, Mark W; Casey, Noel; Lu, Haiyan; Kokiko-Cochran, Olga N; Saman, Sudad; Ericsson, Maria; Onos, Kristen D; Veksler, Ronel; Senatorov, Vladimir V; Kondo, Asami; Zhou, Xiao Z; Miry, Omid; Vose, Linnea R; Gopaul, Katisha R; Upreti, Chirag; Nowinski, Christopher J; Cantu, Robert C; Alvarez, Victor E; Hildebrandt, Audrey M; Franz, Erich S; Konrad, Janusz; Hamilton, James A; Hua, Ning; Tripodis, Yorghos; Anderson, Andrew T; Howell, Gareth R; Kaufer, Daniela; Hall, Garth F; Lu, Kun P; Ransohoff, Richard M; Cleveland, Robin O; Kowall, Neil W; Stein, Thor D; Lamb, Bruce T; Huber, Bertrand R; Moss, William C; Friedman, Alon; Stanton, Patric K; McKee, Ann C; Goldstein, Lee E

    2018-02-01

    The mechanisms underpinning concussion, traumatic brain injury, and chronic traumatic encephalopathy, and the relationships between these disorders, are poorly understood. We examined post-mortem brains from teenage athletes in the acute-subacute period after mild closed-head impact injury and found astrocytosis, myelinated axonopathy, microvascular injury, perivascular neuroinflammation, and phosphorylated tau protein pathology. To investigate causal mechanisms, we developed a mouse model of lateral closed-head impact injury that uses momentum transfer to induce traumatic head acceleration. Unanaesthetized mice subjected to unilateral impact exhibited abrupt onset, transient course, and rapid resolution of a concussion-like syndrome characterized by altered arousal, contralateral hemiparesis, truncal ataxia, locomotor and balance impairments, and neurobehavioural deficits. Experimental impact injury was associated with axonopathy, blood-brain barrier disruption, astrocytosis, microgliosis (with activation of triggering receptor expressed on myeloid cells, TREM2), monocyte infiltration, and phosphorylated tauopathy in cerebral cortex ipsilateral and subjacent to impact. Phosphorylated tauopathy was detected in ipsilateral axons by 24 h, bilateral axons and soma by 2 weeks, and distant cortex bilaterally at 5.5 months post-injury. Impact pathologies co-localized with serum albumin extravasation in the brain that was diagnostically detectable in living mice by dynamic contrast-enhanced MRI. These pathologies were also accompanied by early, persistent, and bilateral impairment in axonal conduction velocity in the hippocampus and defective long-term potentiation of synaptic neurotransmission in the medial prefrontal cortex, brain regions distant from acute brain injury. Surprisingly, acute neurobehavioural deficits at the time of injury did not correlate with blood-brain barrier disruption, microgliosis, neuroinflammation, phosphorylated tauopathy, or

  8. Measurement and Finite Element Model Validation of Immature Porcine Brain-Skull Displacement during Rapid Sagittal Head Rotations.

    Science.gov (United States)

    Pasquesi, Stephanie A; Margulies, Susan S

    2018-01-01

    Computational models are valuable tools for studying tissue-level mechanisms of traumatic brain injury, but to produce more accurate estimates of tissue deformation, these models must be validated against experimental data. In this study, we present in situ measurements of brain-skull displacement in the neonatal piglet head ( n  = 3) at the sagittal midline during six rapid non-impact rotations (two rotations per specimen) with peak angular velocities averaging 51.7 ± 1.4 rad/s. Marks on the sagittally cut brain and skull/rigid potting surfaces were tracked, and peak values of relative brain-skull displacement were extracted and found to be significantly less than values extracted from a previous axial plane model. In a finite element model of the sagittally transected neonatal porcine head, the brain-skull boundary condition was matched to the measured physical experiment data. Despite smaller sagittal plane displacements at the brain-skull boundary, the corresponding finite element boundary condition optimized for sagittal plane rotations is far less stiff than its axial counterpart, likely due to the prominent role of the boundary geometry in restricting interface movement. Finally, bridging veins were included in the finite element model. Varying the bridging vein mechanical behavior over a previously reported range had no influence on the brain-skull boundary displacements. This direction-specific sagittal plane boundary condition can be employed in finite element models of rapid sagittal head rotations.

  9. Measurement and Finite Element Model Validation of Immature Porcine Brain–Skull Displacement during Rapid Sagittal Head Rotations

    Directory of Open Access Journals (Sweden)

    Stephanie A. Pasquesi

    2018-02-01

    Full Text Available Computational models are valuable tools for studying tissue-level mechanisms of traumatic brain injury, but to produce more accurate estimates of tissue deformation, these models must be validated against experimental data. In this study, we present in situ measurements of brain–skull displacement in the neonatal piglet head (n = 3 at the sagittal midline during six rapid non-impact rotations (two rotations per specimen with peak angular velocities averaging 51.7 ± 1.4 rad/s. Marks on the sagittally cut brain and skull/rigid potting surfaces were tracked, and peak values of relative brain–skull displacement were extracted and found to be significantly less than values extracted from a previous axial plane model. In a finite element model of the sagittally transected neonatal porcine head, the brain–skull boundary condition was matched to the measured physical experiment data. Despite smaller sagittal plane displacements at the brain–skull boundary, the corresponding finite element boundary condition optimized for sagittal plane rotations is far less stiff than its axial counterpart, likely due to the prominent role of the boundary geometry in restricting interface movement. Finally, bridging veins were included in the finite element model. Varying the bridging vein mechanical behavior over a previously reported range had no influence on the brain–skull boundary displacements. This direction-specific sagittal plane boundary condition can be employed in finite element models of rapid sagittal head rotations.

  10. Optimising femoral-head osteochondral allograft transplantation in a preclinical model

    Directory of Open Access Journals (Sweden)

    Brett D. Crist

    2016-04-01

    Conclusion: These data provide initial translational and clinical evidence for large osteochondral allografts as a potential option for functional resurfacing of full-thickness cartilage defects of the femoral head.

  11. Design of a Kaplan turbine for a wide range of operating head -Curved draft tube design and model test verification-

    Science.gov (United States)

    KO, Pohan; MATSUMOTO, Kiyoshi; OHTAKE, Norio; DING, Hua

    2016-11-01

    As for turbomachine off-design performance improvement is challenging but critical for maximising the performing area. In this paper, a curved draft tube for a medium head Kaplan type hydro turbine is introduced and discussed for its significant effect on expanding operating head range. Without adding any extra structure and working fluid for swirl destruction and damping, a carefully designed outline shape of draft tube with the selected placement of center-piers successfully supresses the growth of turbulence eddy and the transport of the swirl to the outlet. Also, more kinetic energy is recovered and the head lost is improved. Finally, the model test results are also presented. The obvious performance improvement was found in the lower net head area, where the maximum efficiency improvement was measured up to 20% without compromising the best efficiency point. Additionally, this design results in a new draft tube more compact in size and so leads to better construction and manufacturing cost performance for prototype. The draft tube geometry parameter designing process was concerning the best efficiency point together with the off-design points covering various water net heads and discharges. The hydraulic performance and flow behavior was numerically previewed and visualized by solving Reynolds-Averaged Navier-Stokes equations with Shear Stress Transport turbulence model. The simulation was under the assumption of steady-state incompressible turbulence flow inside the flow passage, and the inlet boundary condition was the carefully simulated flow pattern from the runner outlet. For confirmation, the corresponding turbine efficiency performance of the entire operating area was verified by model test.

  12. An Ex Vivo Model in Human Femoral Heads for Histopathological Study and Resonance Frequency Analysis of Dental Implant Primary Stability

    Science.gov (United States)

    Hernández-Cortés, Pedro; Galindo-Moreno, Pablo; Catena, Andrés; Ortega-Oller, Inmaculada; Salas-Pérez, José; Gómez-Sánchez, Rafael; Aguilar, Mariano; Aguilar, David

    2014-01-01

    Objective. This study was designed to explore relationships of resonance frequency analysis (RFA)—assessed implant stability (ISQ values) with bone morphometric parameters and bone quality in an ex vivo model of dental implants placed in human femoral heads and to evaluate the usefulness of this model for dental implant studies. Material and Methods. This ex vivo study included femoral heads from 17 patients undergoing surgery for femoral neck fracture due to osteoporosis (OP) (n = 7) or for total prosthesis joint replacement due to severe hip osteoarthrosis (OA) (n = 10). Sixty 4.5 × 13 mm Dentsply Astra implants were placed, followed by RFA. CD44 immunohistochemical analysis for osteocytes was also carried out. Results. As expected, the analysis yielded significant effects of femoral head type (OA versus OA) (P implants (P = 0.455) or of the interaction of the two factors (P = 0.848). Bonferroni post hoc comparisons showed a lower mean ISQ for implants in decalcified (50.33 ± 2.92) heads than in fresh (66.93 ± 1.10) or fixated (70.77 ± 1.32) heads (both P 0.5 in all cases), and no significant differences in ISQ values were found as a function of the length or area of the cortical layer (both P > 0.08). Conclusion. Although RFA-determined ISQ values are not correlated with morphometric parameters, they can discriminate bone quality (OP versus OA). This ex vivo model is useful for dental implant studies. PMID:24995307

  13. Feasibility of Primary Tumor Culture Models and Preclinical Prediction Assays for Head and Neck Cancer: A Narrative Review

    International Nuclear Information System (INIS)

    Dohmen, Amy J. C.; Swartz, Justin E.; Van Den Brekel, Michiel W. M.; Willems, Stefan M.; Spijker, René; Neefjes, Jacques; Zuur, Charlotte L.

    2015-01-01

    Primary human tumor culture models allow for individualized drug sensitivity testing and are therefore a promising technique to achieve personalized treatment for cancer patients. This would especially be of interest for patients with advanced stage head and neck cancer. They are extensively treated with surgery, usually in combination with high-dose cisplatin chemoradiation. However, adding cisplatin to radiotherapy is associated with an increase in severe acute toxicity, while conferring only a minor overall survival benefit. Hence, there is a strong need for a preclinical model to identify patients that will respond to the intended treatment regimen and to test novel drugs. One of such models is the technique of culturing primary human tumor tissue. This review discusses the feasibility and success rate of existing primary head and neck tumor culturing techniques and their corresponding chemo- and radiosensitivity assays. A comprehensive literature search was performed and success factors for culturing in vitro are debated, together with the actual value of these models as preclinical prediction assay for individual patients. With this review, we aim to fill a gap in the understanding of primary culture models from head and neck tumors, with potential importance for other tumor types as well

  14. Feasibility of Primary Tumor Culture Models and Preclinical Prediction Assays for Head and Neck Cancer: A Narrative Review

    Energy Technology Data Exchange (ETDEWEB)

    Dohmen, Amy J. C., E-mail: a.dohmen@nki.nl [Department of Head and Neck Surgery and Oncology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek, Plesmanlaan 121, Amsterdam 1066 CX (Netherlands); Department of Cell Biology, the Netherlands Cancer Institute-Antoni van Leeuwenhoek, Plesmanlaan 121, Amsterdam 1066 CX (Netherlands); Swartz, Justin E. [Department of Otorhinolaryngology-Head and Neck Surgery, University Medical Center Utrecht, Heidelberglaan 100, Utrecht 3508 GA (Netherlands); Van Den Brekel, Michiel W. M. [Department of Head and Neck Surgery and Oncology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek, Plesmanlaan 121, Amsterdam 1066 CX (Netherlands); Willems, Stefan M. [Department of Pathology, University Medical Center Utrecht, Heidelberglaan 100, Utrecht 3508 GA (Netherlands); Spijker, René [Medical library, Academic Medical Center, Amsterdam 1100 DE (Netherlands); Dutch Cochrane Centre, Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Heidelberglaan 100, Utrecht 3508 GA (Netherlands); Neefjes, Jacques [Department of Cell Biology, the Netherlands Cancer Institute-Antoni van Leeuwenhoek, Plesmanlaan 121, Amsterdam 1066 CX (Netherlands); Zuur, Charlotte L. [Department of Head and Neck Surgery and Oncology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek, Plesmanlaan 121, Amsterdam 1066 CX (Netherlands)

    2015-08-28

    Primary human tumor culture models allow for individualized drug sensitivity testing and are therefore a promising technique to achieve personalized treatment for cancer patients. This would especially be of interest for patients with advanced stage head and neck cancer. They are extensively treated with surgery, usually in combination with high-dose cisplatin chemoradiation. However, adding cisplatin to radiotherapy is associated with an increase in severe acute toxicity, while conferring only a minor overall survival benefit. Hence, there is a strong need for a preclinical model to identify patients that will respond to the intended treatment regimen and to test novel drugs. One of such models is the technique of culturing primary human tumor tissue. This review discusses the feasibility and success rate of existing primary head and neck tumor culturing techniques and their corresponding chemo- and radiosensitivity assays. A comprehensive literature search was performed and success factors for culturing in vitro are debated, together with the actual value of these models as preclinical prediction assay for individual patients. With this review, we aim to fill a gap in the understanding of primary culture models from head and neck tumors, with potential importance for other tumor types as well.

  15. A two-variable linear model of parotid shrinkage during IMRT for head and neck cancer

    International Nuclear Information System (INIS)

    Broggi, Sara; Fiorino, Claudio; Dell'Oca, Italo; Dinapoli, Nicola; Paiusco, Marta; Muraglia, Alessandro; Maggiulli, Eleonora; Ricchetti, Francesco; Valentini, Vincenzo; Sanguineti, Giuseppe; Cattaneo, Giovanni Mauro; Di Muzio, Nadia; Calandrino, Riccardo

    2010-01-01

    Purpose: To assess anatomical, clinical and dosimetric pre-treatment parameters, possibly predictors of parotid shrinkage during radiotherapy of head and neck cancer (HNC). Materials: Data of 174 parotids from four institutions were analysed; patients were treated with IMRT, with radical and adjuvant intent. Parotid shrinkage was evaluated by the volumetric difference (ΔV) between parotid volumes at the end and those at the start of the therapy, as assessed by CT images (MVCT for 40 patients, KVCT for 47 patients). Correlation between ΔVcc/% and a number of dosimetric, clinical and geometrical parameters was assessed. Univariate as well as stepwise logistic multivariate (MVA) analyses were performed by considering as an end-point a ΔVcc/% larger than the median value. Linear models of ΔV (continuous variable) based on the most predictive variables found at the MVA were developed. Results: Median ΔVcc/% were 6.95 cc and 26%, respectively. The most predictive independent variables of ΔVcc at MVA were the initial parotid volume (IPV, OR: 1.100; p = 0.0002) and Dmean (OR: 1.059; p = 0.038). The main independent predictors of ΔV% at MVA were age (OR: 0.968; p = 0.041) and V40 (OR: 1.0338; p = 0.013). ΔVcc and ΔV% may be well described by the equations: ΔVcc = -2.44 + 0.076 Dmean (Gy) + 0.279 IPV (cc) and ΔV% = 34.23 + 0.192 V40 (%) - 0.2203 age (year). The predictive power of the ΔVcc model is higher than that of the ΔV% model. Conclusions: IPV/age and Dmean/V40 are the major dosimetric and clinical/anatomic predictors of ΔVcc and ΔV%. ΔVcc and ΔV% may be well described by bi-linear models including the above-mentioned variables.

  16. Dosimetric comparison of the specific anthropomorphic mannequin (SAM) to 14 anatomical head models using a novel definition for the mobile phone positioning

    International Nuclear Information System (INIS)

    Kainz, Wolfgang; Christ, Andreas; Kellom, Tocher; Seidman, Seth; Nikoloski, Neviana; Beard, Brian; Kuster, Niels

    2005-01-01

    This paper presents new definitions for obtaining reproducible results in numerical phone dosimetry. Numerous numerical dosimetric studies have been published about the exposure of mobile phone users which concluded with conflicting results. However, many of these studies lack reproducibility due to shortcomings in the description of the phone positioning. The new approach was tested by two groups applying two different numerical program packages to compare the specific anthropomorphic mannequin (SAM) to 14 anatomically correct head models. A novel definition for the positioning of mobile phones next to anatomically correct head models is given along with other essential parameters to be reported. The definition is solely based on anatomical characteristics of the head. A simple up-to-date phone model was used to determine the peak spatial specific absorption rate (SAR) of mobile phones in SAM and in the anatomically correct head models. The results were validated by measurements. The study clearly shows that SAM gives a conservative estimate of the exposure in anatomically correct head models for head only tissue. Depending on frequency, phone position and head size the numerically calculated 10 g averaged SAR in the pinna can be up to 2.1 times greater than the peak spatial SAR in SAM. Measurements in small structures, such as the pinna, will significantly increase the uncertainty; therefore SAM was designed for SAR assessment in the head only. Whether SAM will provide a conservative value for the pinna depends on the pinna SAR limit of the safety standard considered

  17. Comparisons of Computed Mobile Phone Induced SAR in the SAM Phantom to That in Anatomically Correct Models of the Human Head

    Science.gov (United States)

    Beard, Brian B.; Kainz, Wolfgang; Onishi, Teruo; Iyama, Takahiro; Watanabe, Soichi; Fujiwara, Osamu; Wang, Jianqing; Bit-Babik, Giorgi; Faraone, Antonio; Wiart, Joe; Christ, Andreas; Kuster, Niels; Lee, Ae-Kyoung; Kroeze, Hugo; Siegbahn, Martin; Keshvari, Jafar; Abrishamkar, Houman; Simon, Winfried; Manteuffel, Dirk; Nikoloski, Neviana

    2018-01-01

    The specific absorption rates (SAR) determined computationally in the specific anthropomorphic mannequin (SAM) and anatomically correct models of the human head when exposed to a mobile phone model are compared as part of a study organized by IEEE Standards Coordinating Committee 34, SubCommittee 2, and Working Group 2, and carried out by an international task force comprising 14 government, academic, and industrial research institutions. The detailed study protocol defined the computational head and mobile phone models. The participants used different finite-difference time-domain software and independently positioned the mobile phone and head models in accordance with the protocol. The results show that when the pinna SAR is calculated separately from the head SAR, SAM produced a higher SAR in the head than the anatomically correct head models. Also the larger (adult) head produced a statistically significant higher peak SAR for both the 1- and 10-g averages than did the smaller (child) head for all conditions of frequency and position. PMID:29515260

  18. Modelling an advanced ManPAD with dual band detectors and a rosette scanning seeker head

    Science.gov (United States)

    Birchenall, Richard P.; Richardson, Mark A.; Butters, Brian; Walmsley, Roy

    2012-01-01

    Man Portable Air Defence Systems (ManPADs) have been a favoured anti aircraft weapon since their appearance on the military proliferation scene in the mid 1960s. Since this introduction there has been a 'cat and mouse' game of Missile Countermeasures (CMs) and the aircraft protection counter counter measures (CCMs) as missile designers attempt to defeat the aircraft platform protection equipment. Magnesium Teflon Viton (MTV) flares protected the target aircraft until the missile engineers discovered the art of flare rejection using techniques including track memory and track angle bias. These early CCMs relied upon CCM triggering techniques such as the rise rate method which would just sense a sudden increase in target energy and assume that a flare CM had been released by the target aircraft. This was not as reliable as was first thought as aspect changes (bringing another engine into the field of view) or glint from the sun could inadvertently trigger a CCM when not needed. The introduction of dual band detectors in the 1980s saw a major advance in CCM capability allowing comparisons between two distinct IR bands to be made thus allowing the recognition of an MTV flare to occur with minimal false alarms. The development of the rosette scan seeker in the 1980s complemented this advancement allowing the scene in the missile field of view (FOV) to be scanned by a much smaller (1/25) instantaneous FOV (IFOV) with the spectral comparisons being made at each scan point. This took the ManPAD from a basic IR energy detector to a pseudo imaging system capable of analysing individual elements of its overall FOV allowing more complex and robust CCM to be developed. This paper continues the work published in [1,2] and describes the method used to model an advanced ManPAD with a rosette scanning seeker head and robust CCMs similar to the Raytheon Stinger RMP.

  19. Two-Year versus One-Year Head Start Program Impact: Addressing Selection Bias by Comparing Regression Modeling with Propensity Score Analysis

    Science.gov (United States)

    Leow, Christine; Wen, Xiaoli; Korfmacher, Jon

    2015-01-01

    This article compares regression modeling and propensity score analysis as different types of statistical techniques used in addressing selection bias when estimating the impact of two-year versus one-year Head Start on children's school readiness. The analyses were based on the national Head Start secondary dataset. After controlling for…

  20. Dipole estimation errors due to not incorporating anisotropic conductivities in realistic head models for EEG source analysis

    International Nuclear Information System (INIS)

    Hallez, Hans; Staelens, Steven; Lemahieu, Ignace

    2009-01-01

    EEG source analysis is a valuable tool for brain functionality research and for diagnosing neurological disorders, such as epilepsy. It requires a geometrical representation of the human head or a head model, which is often modeled as an isotropic conductor. However, it is known that some brain tissues, such as the skull or white matter, have an anisotropic conductivity. Many studies reported that the anisotropic conductivities have an influence on the calculated electrode potentials. However, few studies have assessed the influence of anisotropic conductivities on the dipole estimations. In this study, we want to determine the dipole estimation errors due to not taking into account the anisotropic conductivities of the skull and/or brain tissues. Therefore, head models are constructed with the same geometry, but with an anisotropically conducting skull and/or brain tissue compartment. These head models are used in simulation studies where the dipole location and orientation error is calculated due to neglecting anisotropic conductivities of the skull and brain tissue. Results show that not taking into account the anisotropic conductivities of the skull yields a dipole location error between 2 and 25 mm, with an average of 10 mm. When the anisotropic conductivities of the brain tissues are neglected, the dipole location error ranges between 0 and 5 mm. In this case, the average dipole location error was 2.3 mm. In all simulations, the dipole orientation error was smaller than 10 deg. We can conclude that the anisotropic conductivities of the skull have to be incorporated to improve the accuracy of EEG source analysis. The results of the simulation, as presented here, also suggest that incorporation of the anisotropic conductivities of brain tissues is not necessary. However, more studies are needed to confirm these suggestions.

  1. Premedication with meloxicam exacerbates intracranial hemorrhage in an immature swine model of non-impact inertial head injury

    OpenAIRE

    Friess, SH; Naim, MY; Kilbaugh, TJ; Ralston, J; Margulies, SS

    2012-01-01

    Meloxicam is a cyclo-oxgenase-2 preferential non-steroid anti-inflammatory drug with very effective analgesic and anti-inflammatory effects in swine. Previous reports in piglets have demonstrated that meloxicam also inhibits cyclo-oxgenase-1 and reduces production of thromboxane significantly. We use pre-injury analgesia in our immature swine (3–5 day old piglets) model of brain injury using rapid head rotations without impact. In 23 consecutive subjects we found that premedication with melox...

  2. An Ex Vivo Model in Human Femoral Heads for Histopathological Study and Resonance Frequency Analysis of Dental Implant Primary Stability

    Directory of Open Access Journals (Sweden)

    Pedro Hernández-Cortés

    2014-01-01

    Full Text Available Objective. This study was designed to explore relationships of resonance frequency analysis (RFA—assessed implant stability (ISQ values with bone morphometric parameters and bone quality in an ex vivo model of dental implants placed in human femoral heads and to evaluate the usefulness of this model for dental implant studies. Material and Methods. This ex vivo study included femoral heads from 17 patients undergoing surgery for femoral neck fracture due to osteoporosis (OP (n=7 or for total prosthesis joint replacement due to severe hip osteoarthrosis (OA (n=10. Sixty 4.5×13 mm Dentsply Astra implants were placed, followed by RFA. CD44 immunohistochemical analysis for osteocytes was also carried out. Results. As expected, the analysis yielded significant effects of femoral head type (OA versus OA (P0.5 in all cases, and no significant differences in ISQ values were found as a function of the length or area of the cortical layer (both P>0.08. Conclusion. Although RFA-determined ISQ values are not correlated with morphometric parameters, they can discriminate bone quality (OP versus OA. This ex vivo model is useful for dental implant studies.

  3. The effects of simulating a realistic eye model on the eye dose of an adult male undergoing head computed tomography.

    Science.gov (United States)

    Akhlaghi, Parisa; Ebrahimi-Khankook, Atiyeh; Vejdani-Noghreiyan, Alireza

    2017-05-01

    In head computed tomography, radiation upon the eye lens (as an organ with high radiosensitivity) may cause lenticular opacity and cataracts. Therefore, quantitative dose assessment due to exposure of the eye lens and surrounding tissue is a matter of concern. For this purpose, an accurate eye model with realistic geometry and shape, in which different eye substructures are considered, is needed. To calculate the absorbed radiation dose of visual organs during head computed tomography scans, in this study, an existing sophisticated eye model was inserted at the related location in the head of the reference adult male phantom recommended by the International Commission on Radiological Protection (ICRP). Then absorbed doses and distributions of energy deposition in different parts of this eye model were calculated and compared with those based on a previous simple eye model. All calculations were done using the Monte Carlo code MCNP4C for tube voltages of 80, 100, 120 and 140 kVp. In spite of the similarity of total dose to the eye lens for both eye models, the dose delivered to the sensitive zone, which plays an important role in the induction of cataracts, was on average 3% higher for the sophisticated model as compared to the simple model. By increasing the tube voltage, differences between the total dose to the eye lens between the two phantoms decrease to 1%. Due to this level of agreement, use of the sophisticated eye model for patient dosimetry is not necessary. However, it still helps for an estimation of doses received by different eye substructures separately.

  4. Construction of a biomechanical head and neck motion model as a guide to evaluation of deformable image registration

    Science.gov (United States)

    Teske, Hendrik; Bartelheimer, Kathrin; Meis, Jan; Bendl, Rolf; Stoiber, Eva M.; Giske, Kristina

    2017-06-01

    The use of deformable image registration methods in the context of adaptive radiotherapy leads to uncertainties in the simulation of the administered dose distributions during the treatment course. Evaluation of these methods is a prerequisite to decide if a plan adaptation will improve the individual treatment. Current approaches using manual references limit the validity of evaluation, especially for low-contrast regions. In particular, for the head and neck region, the highly flexible anatomy and low soft tissue contrast in control images pose a challenge to image registration and its evaluation. Biomechanical models promise to overcome this issue by providing anthropomorphic motion modelling of the patient. We introduce a novel biomechanical motion model for the generation and sampling of different postures of the head and neck anatomy. Motion propagation behaviour of the individual bones is defined by an underlying kinematic model. This model interconnects the bones by joints and thus is capable of providing a wide range of motion. Triggered by the motion of the individual bones, soft tissue deformation is described by an extended heterogeneous tissue model based on the chainmail approach. This extension, for the first time, allows the propagation of decaying rotations within soft tissue without the necessity for explicit tissue segmentation. Overall motion simulation and sampling of deformed CT scans including a basic noise model is achieved within 30 s. The proposed biomechanical motion model for the head and neck site generates displacement vector fields on a voxel basis, approximating arbitrary anthropomorphic postures of the patient. It was developed with the intention of providing input data for the evaluation of deformable image registration.

  5. A model of head-related transfer functions based on a state-space analysis

    Science.gov (United States)

    Adams, Norman Herkamp

    This dissertation develops and validates a novel state-space method for binaural auditory display. Binaural displays seek to immerse a listener in a 3D virtual auditory scene with a pair of headphones. The challenge for any binaural display is to compute the two signals to supply to the headphones. The present work considers a general framework capable of synthesizing a wide variety of auditory scenes. The framework models collections of head-related transfer functions (HRTFs) simultaneously. This framework improves the flexibility of contemporary displays, but it also compounds the steep computational cost of the display. The cost is reduced dramatically by formulating the collection of HRTFs in the state-space and employing order-reduction techniques to design efficient approximants. Order-reduction techniques based on the Hankel-operator are found to yield accurate low-cost approximants. However, the inter-aural time difference (ITD) of the HRTFs degrades the time-domain response of the approximants. Fortunately, this problem can be circumvented by employing a state-space architecture that allows the ITD to be modeled outside of the state-space. Accordingly, three state-space architectures are considered. Overall, a multiple-input, single-output (MISO) architecture yields the best compromise between performance and flexibility. The state-space approximants are evaluated both empirically and psychoacoustically. An array of truncated FIR filters is used as a pragmatic reference system for comparison. For a fixed cost bound, the state-space systems yield lower approximation error than FIR arrays for D>10, where D is the number of directions in the HRTF collection. A series of headphone listening tests are also performed to validate the state-space approach, and to estimate the minimum order N of indiscriminable approximants. For D = 50, the state-space systems yield order thresholds less than half those of the FIR arrays. Depending upon the stimulus uncertainty, a

  6. Parenting Classes, Parenting Behavior, and Child Cognitive Development in Early Head Start: A Longitudinal Model

    Science.gov (United States)

    Chang, Mido; Park, Boyoung; Kim, Sunha

    2009-01-01

    This study analyzed Early Head Start Research and Evaluation (EHSRE) study data, examining the effect of parenting classes on parenting behaviors and children's cognitive outcomes. The study analyzed three sets of dependent variables: parental language and cognitive stimulation, parent-child interactive activities, and the Bayley Mental…

  7. Automatic Patient Modeling for Hyperthermia Treatment Planning of Head and Neck Cancer

    NARCIS (Netherlands)

    V. Fortunati (Valerio)

    2015-01-01

    markdownabstractHead and neck (H&N) cancer is the term used to describe a wide range of malig- nant tumors originating in the upper airways and swallowing tracts. In 2012, this disease accounted for approximately 5% of all cancers worldwide, with 680,000 new cases diagnosed and 370,000 recorded

  8. Compression of head-related transfer function using autoregressive-moving-average models and Legendre polynomials

    DEFF Research Database (Denmark)

    Shekarchi, Sayedali; Hallam, John; Christensen-Dalsgaard, Jakob

    2013-01-01

    -moving-average (ARMA) filters whose coefficients are calculated using Prony's method. Such filters are specified by a few coefficients which can generate the full head-related impulse responses (HRIRs). Next, Legendre polynomials (LPs) are used to compress the ARMA filter coefficients. LPs are derived on the sphere...

  9. Modelling the species distribution of flat-headed cats (Prionailurus planiceps, an endangered South-East Asian small felid.

    Directory of Open Access Journals (Sweden)

    Andreas Wilting

    Full Text Available BACKGROUND: The flat-headed cat (Prionailurus planiceps is one of the world's least known, highly threatened felids with a distribution restricted to tropical lowland rainforests in Peninsular Thailand/Malaysia, Borneo and Sumatra. Throughout its geographic range large-scale anthropogenic transformation processes, including the pollution of fresh-water river systems and landscape fragmentation, raise concerns regarding its conservation status. Despite an increasing number of camera-trapping field surveys for carnivores in South-East Asia during the past two decades, few of these studies recorded the flat-headed cat. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we designed a predictive species distribution model using the Maximum Entropy (MaxEnt algorithm to reassess the potential current distribution and conservation status of the flat-headed cat. Eighty-eight independent species occurrence records were gathered from field surveys, literature records, and museum collections. These current and historical records were analysed in relation to bioclimatic variables (WorldClim, altitude (SRTM and minimum distance to larger water resources (Digital Chart of the World. Distance to water was identified as the key predictor for the occurrence of flat-headed cats (>50% explanation. In addition, we used different land cover maps (GLC2000, GlobCover and SarVision LLC for Borneo, information on protected areas and regional human population density data to extract suitable habitats from the potential distribution predicted by the MaxEnt model. Between 54% and 68% of suitable habitat has already been converted to unsuitable land cover types (e.g. croplands, plantations, and only between 10% and 20% of suitable land cover is categorised as fully protected according to the IUCN criteria. The remaining habitats are highly fragmented and only a few larger forest patches remain. CONCLUSION/SIGNIFICANCE: Based on our findings, we recommend that future conservation

  10. Heads Up

    Science.gov (United States)

    ... Form Controls Cancel Submit Search the CDC HEADS UP Note: Javascript is disabled or is not supported ... please visit this page: About CDC.gov . HEADS UP Brain Injury Basics What Is a Concussion? Concussion ...

  11. Improving inferences from short-term ecological studies with Bayesian hierarchical modeling: white-headed woodpeckers in managed forests.

    Science.gov (United States)

    Linden, Daniel W; Roloff, Gary J

    2015-08-01

    Pilot studies are often used to design short-term research projects and long-term ecological monitoring programs, but data are sometimes discarded when they do not match the eventual survey design. Bayesian hierarchical modeling provides a convenient framework for integrating multiple data sources while explicitly separating sample variation into observation and ecological state processes. Such an approach can better estimate state uncertainty and improve inferences from short-term studies in dynamic systems. We used a dynamic multistate occupancy model to estimate the probabilities of occurrence and nesting for white-headed woodpeckers Picoides albolarvatus in recent harvest units within managed forests of northern California, USA. Our objectives were to examine how occupancy states and state transitions were related to forest management practices, and how the probabilities changed over time. Using Gibbs variable selection, we made inferences using multiple model structures and generated model-averaged estimates. Probabilities of white-headed woodpecker occurrence and nesting were high in 2009 and 2010, and the probability that nesting persisted at a site was positively related to the snag density in harvest units. Prior-year nesting resulted in higher probabilities of subsequent occurrence and nesting. We demonstrate the benefit of forest management practices that increase the density of retained snags in harvest units for providing white-headed woodpecker nesting habitat. While including an additional year of data from our pilot study did not drastically alter management recommendations, it changed the interpretation of the mechanism behind the observed dynamics. Bayesian hierarchical modeling has the potential to maximize the utility of studies based on small sample sizes while fully accounting for measurement error and both estimation and model uncertainty, thereby improving the ability of observational data to inform conservation and management strategies.

  12. Three-dimensional biomimetic head model as a platform for thermal testing of protective goggles for prevention of eye injuries.

    Science.gov (United States)

    Friedman, Rinat; Haimy, Ayelet; Gefen, Amit; Epstein, Yoram

    2018-04-22

    The rate of eye injury is steadily rising during military conflicts of the century, with thermal burns being the most common type of injury to the eyes. The present study focuses on assessing the heat resistance properties of military protective goggles using three-dimensional (3D) finite element head modeling fitted with the tested protective gear. A computational thermal impact was applied onto a 3D biomimetic human head model fitted with two goggle models - sports (Type 1) and square (Type 2). The resultant temperature of the eye tissues and the thermal injury thresholds were calculated by using the modeling, hence allowing to determine the protective efficacy of the goggles objectively, in a standardized, quantitative and cost-effective manner. Both types of goggles had a dramatic protective effect on the eyes. The specific goggle geometry had no notable effect on the level of protection to the inner tissues against the thermal insult. At the skin level goggles reduced temperatures by ~64% under the impact zone, with only a mild difference (10 °C) between the goggles. Little limitations on the shape and geometry of goggles were observed and any structure of goggles can provide an adequate protection against a thermal insult (per se) to inner cranial tissues, assuming the lenses are wide and thick enough to block direct skin contact of the heat insult. It was shown that our 3D biomimetic human head model provides a practical and cost-effective tool for determining the performance level of goggles with different attributed (i.e., shapes and thermal properties). Copyright © 2018 Elsevier Ltd. All rights reserved.

  13. An improved finite element modeling of the cerebrospinal fluid layer in the head impact analysis.

    Science.gov (United States)

    Wu, John Z; Pan, Christopher S; Wimer, Bryan M; Rosen, Charles L

    2017-01-01

    The finite element (FE) method has been widely used to investigate the mechanism of traumatic brain injuries (TBIs), because it is technically difficult to quantify the responses of the brain tissues to the impact in experiments. One of technical challenges to build a FE model of a human head is the modeling of the cerebrospinal fluid (CSF) of the brain. In the current study, we propose to use membrane elements to construct the CSF layer. Using the proposed approach, we demonstrate that a head model can be built by using existing meshes available in commercial databases, without using any advanced meshing software tool, and with the sole use of native functions of the FE package Abaqus. The calculated time histories of the intracranial pressures at frontal, posterior fossa, parietal, and occipital positions agree well with the experimental data and the simulations in the literature, indicating that the physical effects of the CSF layer have been accounted for in the proposed modeling approach. The proposed modeling approach would be useful for bioengineers to solve practical problems.

  14. Water flux characterization through hydraulic head and temperature data assimilation: Numerical modeling and sandbox experiments

    Science.gov (United States)

    Ju, Lei; Zhang, Jiangjiang; Chen, Cheng; Wu, Laosheng; Zeng, Lingzao

    2018-03-01

    Spatial distribution of groundwater recharge/discharge fluxes has an important impact on mass and energy exchanges in shallow streambeds. During the last two decades, extensive studies have been devoted to the quantification of one-dimensional (1-D) vertical exchange fluxes. Nevertheless, few studies were conducted to characterize two-dimensional (2-D) heterogeneous flux fields that commonly exist in real-world cases. In this study, we used an iterative ensemble smoother (IES) to quantify the spatial distribution of 2-D exchange fluxes by assimilating hydraulic head and temperature measurements. Four assimilation scenarios corresponding to different potential field applications were tested. In the first three scenarios, the heterogeneous hydraulic conductivity fields were first inferred from hydraulic head and/or temperature measurements, and then the flux fields were derived through Darcy's law using the estimated conductivity fields. In the fourth scenario, the flux fields were estimated directly from the temperature measurements, which is more efficient and especially suitable for the situation that a complete knowledge of flow boundary conditions is unavailable. We concluded that, the best estimation could be achieved through jointly assimilating hydraulic head and temperature measurements, and temperature data were superior to the head data when they were used independently. Overall, the IES method provided more robust and accurate vertical flux estimations than those given by the widely used analytical solution-based methods. Furthermore, IES gave reasonable uncertainty estimations, which were unavailable in traditional methods. Since temperature can be accurately monitored with high spatial and temporal resolutions, the coupling of heat tracing techniques and IES provides promising potential in quantifying complex exchange fluxes under field conditions.

  15. Central Pain Mechanisms and Novel Therapeutic Strategies in a Model of Closed Head Injury

    Science.gov (United States)

    2015-10-01

    headache Post-traumatic migraine Chronic migraine Traumatic brain injury Quantitative EEG (QEEG) Analgesia Endocannabinoid Cannabinoid receptors...chronic (4 week) closed head injury groups for EEG studies. On our current EEG system , only 4 rats can be run at a time for a 4-week period...Completed installation, calibration and testing of a new EEG system from Pinnacle. Hired and trained an upper level Research Associate (Dr. Lan Cheng, MD

  16. Modelling and assessment of the electric field strength caused by mobile phone to the human head

    Directory of Open Access Journals (Sweden)

    Buckus Raimondas

    2016-01-01

    Full Text Available Background/Aim. Electromagnetic field exposure is the one of the most important physical agents that actively affects live organisms and environment. Active use of mobile phones influences the increase of electromagnetic field radiation. The aim of the study was to measure and assess the electric field strength caused by mobile phones to the human head. Methods. In this paper the software “COMSOL Multiphysics” was used to establish the electric field strength created by mobile phones around the head. Results. The second generation (2G Global System for Mobile (GSM phones that operate in the frequency band of 900 MHz and reach the power of 2 W have a stronger electric field than (2G GSM mobile phones that operate in the higher frequency band of 1,800 MHz and reach the power up to 1 W during conversation. The third generation of (3G UMTS smart phones that effectively use high (2,100 MHz radio frequency band emit the smallest electric field strength values during conversation. The highest electric field strength created by mobile phones is around the ear, i.e. the mobile phone location. The strength of mobile phone electric field on the phantom head decreases exponentially while moving sidewards from the center of the effect zone (the ear, and constitutes 1-12% of the artificial head’s surface. Conclusion. The highest electric field strength values of mobile phones are associated with their higher power, bigger specific energy absorption rate (SAR and lower frequency of mobile phone. The stronger electric field emitted by the more powerful mobile phones takes a higher percentage of the head surface. The highest electric field strength created by mobile phones is distributed over the user ear.

  17. Pre-clinical evaluation of ceramic femoral head resurfacing prostheses using computational models and mechanical testing.

    Science.gov (United States)

    Dickinson, A S; Browne, M; Wilson, K C; Leffers, J R T; Taylor, A C

    2011-09-01

    Ceramic-on-ceramic hip resurfacing can potentially offer the bone-conserving advantages of resurfacing while eliminating metal ion release. Thin-walled ceramic resurfacing heads are conceivable following developments in the strength and reliability of ceramic materials, but verification of new designs is required. The present study aimed to develop a mechanical pre-clinical analysis verification process for ceramic resurfacing heads, using the DeltaSurf prosthesis design as a case study. Finite element analysis of a range of in vivo scenarios was used to design a series of physiologically representative mechanical tests, which were conducted to verify the strength of the prosthesis. Tests were designed to simulate ideal and worst-case in vivo loading and support, or to allow comparison with a clinically successful metallic device. In tests simulating ideal loading and support, the prosthesis sustained a minimum load of 39 kN before fracture, and survived 10 000 000 fatigue cycles of 0.534 kN to 5.34 kN. In worst-case tests representing a complete lack of superior femoral head bone support or pure cantilever loading of the prosthesis stem, the design demonstrated strength comparable to that of the equivalent metal device. The developed mechanical verification test programme represents an improvement in the state of the art where international test standards refer largely to total hip replacement prostheses. The case study's novel prosthesis design performed with considerable safety margins compared with extreme in vivo loads, providing evidence that the proposed ceramic resurfacing heads should have sufficient strength to perform safely in vivo. Similar verification tests should be designed and conducted for novel ceramic prosthesis designs in the future, leading the way to clinical evaluation.

  18. Hubungan Persepsi Dengan Hasil Belajar Siswa Pada Pembelajaran Biologi Menggunakan Model Kooperatif Tipe Numbered Heads Together (Nht) Kelas XI IPA Di SMA N 2 Tambang

    OpenAIRE

    Putri, Herizky Dwi Utami; Fauziah, Yuslim; Febrita, Elya

    2017-01-01

    This study aims to determine the relationship of perception with student learning outcomes on biology learning using cooperative model Numbered Heads Together (NHT) class XI IPA in SMA N 2 Tambang. This research was conducted in September 2016. The sample in this research is 62 students of class XI IPAI and class XI IPAII academic year 2016/2017. Parameter of this research (1) student's perception toward applying cooperative learning model of typeed heads Together (NHT) with 5 indicators that...

  19. Effects of dwell time of excitation waveform on meniscus movements for a tubular piezoelectric print-head: experiments and model

    Science.gov (United States)

    Chang, Jiaqing; Liu, Yaxin; Huang, Bo

    2017-07-01

    In inkjet applications, it is normal to search for an optimal drive waveform when dispensing a fresh fluid or adjusting a newly fabricated print-head. To test trial waveforms with different dwell times, a camera and a strobe light were used to image the protruding or retracting liquid tongues without ejecting any droplets. An edge detection method was used to calculate the lengths of the liquid tongues to draw the meniscus movement curves. The meniscus movement is determined by the time-domain response of the acoustic pressure at the nozzle of the print-head. Starting at the inverse piezoelectric effect, a mathematical model which considers the liquid viscosity in acoustic propagation is constructed to study the acoustic pressure response at the nozzle of the print-head. The liquid viscosity retards the propagation speed and dampens the harmonic amplitude. The pressure response, which is the combined effect of the acoustic pressures generated during the rising time and the falling time and after their propagations and reflections, explains the meniscus movements well. Finally, the optimal dwell time for droplet ejections is discussed.

  20. Effects of dwell time of excitation waveform on meniscus movements for a tubular piezoelectric print-head: experiments and model

    International Nuclear Information System (INIS)

    Chang, Jiaqing; Liu, Yaxin; Huang, Bo

    2017-01-01

    In inkjet applications, it is normal to search for an optimal drive waveform when dispensing a fresh fluid or adjusting a newly fabricated print-head. To test trial waveforms with different dwell times, a camera and a strobe light were used to image the protruding or retracting liquid tongues without ejecting any droplets. An edge detection method was used to calculate the lengths of the liquid tongues to draw the meniscus movement curves. The meniscus movement is determined by the time-domain response of the acoustic pressure at the nozzle of the print-head. Starting at the inverse piezoelectric effect, a mathematical model which considers the liquid viscosity in acoustic propagation is constructed to study the acoustic pressure response at the nozzle of the print-head. The liquid viscosity retards the propagation speed and dampens the harmonic amplitude. The pressure response, which is the combined effect of the acoustic pressures generated during the rising time and the falling time and after their propagations and reflections, explains the meniscus movements well. Finally, the optimal dwell time for droplet ejections is discussed. (paper)

  1. Finite Element Models Development of Car Seats With Passive Head Restraints to Study Their Meeting Requirements for EURO NCAP

    Directory of Open Access Journals (Sweden)

    D. Yu. Solopov

    2014-01-01

    Full Text Available In performing calculations to evaluate passive safety of car seats by computer modelling methods it is desirable to use the final element models (FEM thereby providing the greatest accuracy of calculation results. Besides, it is expedient to use FEM, which can be calculated by computer for a small period of time to give preliminary results for short terms.The paper describes the features to evaluate a passive safety, which is ensured by the developed KEM of seats with passive head restraints according to requirements of the EURO NCAP.Besides, accuracy of calculated results that is provided by the developed KEM was evaluated. Accuracy evaluation was accomplished in relation to the results obtained the by specialists of the organization conducting similar researches (LSTC.This work was performed within the framework of a technique, which allows us to develop effectively the car seat designs both with passive, and active head restraints, meeting requirements for passive safety.By results of made calculations and experiments it was found that when evaluating by the EURO NCAP technique the "rough" KEM (the 1st and 2nd levels can be considered as rational ones (in terms of labour costs for its creation and problem solving as well as by result errors and it is expedient to use them for preliminary and multivariate calculations. Detailed models (the 3rd level provide the greatest accuracy (the greatest accuracy is reached with the evaluated impact of 16km/h speed under the loading conditions "moderate impact". A relative error of full head acceleration is of 12%.In evaluation by EURO NCAP using NIC criterion a conclusion can be drawn that the seat models of the 2nd level (467 936 KE and the 3rd level (1 255 358 KE meet the passive safety requirements according to EURO NCAP requirements under "light", "moderate", and "heavy" impacts.In evaluation by EURO NCAP for preliminary and multivariate calculations a model of the middle level (consisting of 467

  2. Creating the finite element models of car seats with passive head restraints to meet the requirements of passive safety

    Directory of Open Access Journals (Sweden)

    D. Yu. Solopov

    2014-01-01

    Full Text Available A problem solution to create the car chairs using modern software complexes (CAE based on the finite elements is capable to increase an efficiency of designing process significantly. Designing process is complicated by the fact that at present there are no available techniques focused on this sort of tasks.This article shows the features to create the final element models (FEM of the car chairs having three levels of complexity. It assesses a passive safety, which is ensured by the developed chair models with passive head restraints according to requirements of UNECE No 25 Regulations, and an accuracy of calculation results compared with those of full-scale experiments.This work is part of the developed technique, which allows effective development of the car chair designs both with passive, and with active head restraints, meeting the requirements of passive safety.By results of calculations and experiments it was established that at assessment by an UNECE No 25 technique the "rough" FEM (the 1st and 2nd levels can be considered as rational (in terms of effort to its creation and task solution and by the errors of results, and it is expedient to use them for preliminary and multiple calculations. Detailed models (the 3rd level provide the greatest accuracy (for accelerations the relative error makes 10%, for movements it is 11%, while in comparison with calculations, the relative error for a model of head restraint only decreases by 5% for accelerations and for 9% for movements.The materials presented in the article are used both in research activities and in training students at the Chair of Wheel Vehicles of the Scientific and Educational Complex "Special Mechanical Engineering" of Bauman Moscow State Technical University.

  3. Image quality analysis of high-density diffuse optical tomography incorporating a subject-specific head model

    Directory of Open Access Journals (Sweden)

    Yuxuan eZhan

    2012-05-01

    Full Text Available High-density diffuse optical tomography (HD-DOT methods have shown significant improvement in localization accuracy and image resolution compared to traditional topographic near infrared spectroscopy (NIRS of the human brain. In this work we provide a comprehensive evaluation of image quality in visual cortex mapping via a simulation study with the use of an anatomical head model derived from MRI data of a human subject. A model of individual head anatomy provides the surface shape and internal structure that allow for the construction of a more realistic physical model for the forward problem, as well as the use of a structural constraint in the inverse problem. The HD-DOT model utilized here incorporates multiple source-detector separations with continuous-wave data with added noise based on experimental results. To evaluate image quality we quantify the localization error and localized volume at half maximum (LVHM throughout a region of interest (ROI within the visual cortex and systematically analyze the use of whole brain tissue spatial constraint within image reconstruction. Our results demonstrate that an image quality with less than 10 mm in localization error and 1000 m3 in LVHM can be obtained up to 13 mm below the scalp surface with a typical unconstrained reconstruction and up to 18 mm deep when a spatial constraint based on the brain tissue is utilized.

  4. Impact of head models in N170 component source imaging: results in control subjects and ADHD patients

    International Nuclear Information System (INIS)

    Beltrachini, L; Blenkmann, A; Ellenrieder, N von; Muravchik, C H; Petroni, A; Urquina, H; Manes, F; Ibáñez, A

    2011-01-01

    The major goal of evoked related potential studies arise in source localization techniques to identify the loci of neural activity that give rise to a particular voltage distribution measured on the surface of the scalp. In this paper we evaluate the effect of the head model adopted in order to estimate the N170 component source in attention deficit hyperactivity disorder (ADHD) patients and control subjects, considering faces and words stimuli. The standardized low resolution brain electromagnetic tomography algorithm (sLORETA) is used to compare between the three shell spherical head model and a fully realistic model based on the ICBM-152 atlas. We compare their variance on source estimation and analyze the impact on the N170 source localization. Results show that the often used three shell spherical model may lead to erroneous solutions, specially on ADHD patients, so its use is not recommended. Our results also suggest that N170 sources are mainly located in the right occipital fusiform gyrus for faces stimuli and in the left occipital fusiform gyrus for words stimuli, for both control subjects and ADHD patients. We also found a notable decrease on the N170 estimated source amplitude on ADHD patients, resulting in a plausible marker of the disease.

  5. Impact of head models in N170 component source imaging: results in control subjects and ADHD patients

    Science.gov (United States)

    Beltrachini, L.; Blenkmann, A.; von Ellenrieder, N.; Petroni, A.; Urquina, H.; Manes, F.; Ibáñez, A.; Muravchik, C. H.

    2011-12-01

    The major goal of evoked related potential studies arise in source localization techniques to identify the loci of neural activity that give rise to a particular voltage distribution measured on the surface of the scalp. In this paper we evaluate the effect of the head model adopted in order to estimate the N170 component source in attention deficit hyperactivity disorder (ADHD) patients and control subjects, considering faces and words stimuli. The standardized low resolution brain electromagnetic tomography algorithm (sLORETA) is used to compare between the three shell spherical head model and a fully realistic model based on the ICBM-152 atlas. We compare their variance on source estimation and analyze the impact on the N170 source localization. Results show that the often used three shell spherical model may lead to erroneous solutions, specially on ADHD patients, so its use is not recommended. Our results also suggest that N170 sources are mainly located in the right occipital fusiform gyrus for faces stimuli and in the left occipital fusiform gyrus for words stimuli, for both control subjects and ADHD patients. We also found a notable decrease on the N170 estimated source amplitude on ADHD patients, resulting in a plausible marker of the disease.

  6. SU-E-T-08: A Convolution Model for Head Scatter Fluence in the Intensity Modulated Field

    Energy Technology Data Exchange (ETDEWEB)

    Chen, M; Mo, X; Chen, Y; Parnell, D; Key, S; Olivera, G; Galmarini, W; Lu, W

    2014-06-01

    Purpose: To efficiently calculate the head scatter fluence for an arbitrary intensity-modulated field with any source distribution using the source occlusion model. Method: The source occlusion model with focal and extra focal radiation (Jaffray et al, 1993) can be used to account for LINAC head scatter. In the model, the fluence map of any field shape at any point can be calculated via integration of the source distribution within the visible range, as confined by each segment, using the detector eye's view. A 2D integration would be required for each segment and each fluence plane point, which is time-consuming, as an intensity-modulated field contains typically tens to hundreds of segments. In this work, we prove that the superposition of the segmental integrations is equivalent to a simple convolution regardless of what the source distribution is. In fact, for each point, the detector eye's view of the field shape can be represented as a function with the origin defined at the point's pinhole reflection through the center of the collimator plane. We were thus able to reduce hundreds of source plane integration to one convolution. We calculated the fluence map for various 3D and IMRT beams and various extra-focal source distributions using both the segmental integration approach and the convolution approach and compared the computation time and fluence map results of both approaches. Results: The fluence maps calculated using the convolution approach were the same as those calculated using the segmental approach, except for rounding errors (<0.1%). While it took considerably longer time to calculate all segmental integrations, the fluence map calculation using the convolution approach took only ∼1/3 of the time for typical IMRT fields with ∼100 segments. Conclusions: The convolution approach for head scatter fluence calculation is fast and accurate and can be used to enhance the online process.

  7. A GIS-Based Proposal for Modeling the “Lenteja” Zone of the CIEMAT Head Courted (Madrid)

    International Nuclear Information System (INIS)

    Marina, J; Andrés, N de; Carroza, J.A; Quiñones, J.

    2015-01-01

    CIEMAT is devoted to different activities relate to Decommissioning and Dismantling of all Radioactive irradiation facilities. Focusing on that this paper has the main objective of: to design a methodology for evaluating the geological structure of the site. This methodology allows description, modelling of the radionuclide migration in the soil. Although the idea is following the same methodology input the rest of the CIEMAT head courter site. In this paper is written a detailed description of the block diagram and geological profiles obtained, in which the sedimentary architecture of the subsoil of the study area and the location and volume of confined aquifers present in ''lenteja'' are localised.

  8. Vasculature deprivation – induced osteonecrosis of the rat femoral head as a model for therapeutic trials

    Science.gov (United States)

    Bejar, Jacob; Peled, Eli; Boss, Jochanan H

    2005-01-01

    Experimental Osteonecrosis The authors' experience with experimentally produced femoral capital osteonecrosis in rats is reviewed: incising the periosteum at the base of the neck of the femur and cutting the ligamentum teres leads to coagulation necrosis of the epiphysis. The necrotic debris is substituted by fibrous tissue concomitantly with resorption of the dead soft and hard tissues by macrophages and osteoclasts, respectively. Progressively, the formerly necrotic epiphysis is repopulated by hematopoietic-fatty tissue, and replaced by architecturally abnormal and biomechanically weak bone. The femoral heads lose their smooth-surfaced hemispherical shape in the wake of the load transfer through the hip joint such that, together with regressive changes of the joint cartilage and inflammatory-hyperplastic changes of the articular membrane, an osteoarthritis-like disorder ensues. Therapeutic Choices Diverse therapeutic options are studied to satisfy the different opinions concerning the significance of diverse etiological and pathogenic mechanisms: 1. Exposure to hyperbaric oxygen. 2. Exposure to hyperbaric oxygen and non-weight bearing on the operated hip. 3. Medication with enoxaparin. 4. Reduction of intraosseous hypertension, putting to use a procedure aimed at core decompression, namely drilling a channel through the femoral head. 5. Medication with vascular endothelial growth factor with a view to accelerating revascularization. 6. Medication with zoledronic acid to decrease osteoclastic productivity such that the remodeling of the femoral head is slowed. Glucocorticoid-related osteonecrosis appears to be apoptosis-related, thus differing from the vessel-deprivation-induced tissue coagulation found in idiopathic osteonecrosis. The quantities of TNF-α, RANK-ligand and osteoprotegerin are raised in glucocorticoid-treated osteoblasts so that the differentiation of osteoclasts is blocked. Moreover, the osteoblasts and osteocytes of the femoral cortex mostly

  9. Toward integration of genomic selection with crop modelling: the development of an integrated approach to predicting rice heading dates.

    Science.gov (United States)

    Onogi, Akio; Watanabe, Maya; Mochizuki, Toshihiro; Hayashi, Takeshi; Nakagawa, Hiroshi; Hasegawa, Toshihiro; Iwata, Hiroyoshi

    2016-04-01

    It is suggested that accuracy in predicting plant phenotypes can be improved by integrating genomic prediction with crop modelling in a single hierarchical model. Accurate prediction of phenotypes is important for plant breeding and management. Although genomic prediction/selection aims to predict phenotypes on the basis of whole-genome marker information, it is often difficult to predict phenotypes of complex traits in diverse environments, because plant phenotypes are often influenced by genotype-environment interaction. A possible remedy is to integrate genomic prediction with crop/ecophysiological modelling, which enables us to predict plant phenotypes using environmental and management information. To this end, in the present study, we developed a novel method for integrating genomic prediction with phenological modelling of Asian rice (Oryza sativa, L.), allowing the heading date of untested genotypes in untested environments to be predicted. The method simultaneously infers the phenological model parameters and whole-genome marker effects on the parameters in a Bayesian framework. By cultivating backcross inbred lines of Koshihikari × Kasalath in nine environments, we evaluated the potential of the proposed method in comparison with conventional genomic prediction, phenological modelling, and two-step methods that applied genomic prediction to phenological model parameters inferred from Nelder-Mead or Markov chain Monte Carlo algorithms. In predicting heading dates of untested lines in untested environments, the proposed and two-step methods tended to provide more accurate predictions than the conventional genomic prediction methods, particularly in environments where phenotypes from environments similar to the target environment were unavailable for training genomic prediction. The proposed method showed greater accuracy in prediction than the two-step methods in all cross-validation schemes tested, suggesting the potential of the integrated approach in

  10. Normal Tissue Complication Probability Modeling of Radiation-Induced Hypothyroidism After Head-and-Neck Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Bakhshandeh, Mohsen [Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Hashemi, Bijan, E-mail: bhashemi@modares.ac.ir [Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Mahdavi, Seied Rabi Mehdi [Department of Medical Physics, Faculty of Medical Sciences, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Nikoofar, Alireza; Vasheghani, Maryam [Department of Radiation Oncology, Hafte-Tir Hospital, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Kazemnejad, Anoshirvan [Department of Biostatistics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of)

    2013-02-01

    Purpose: To determine the dose-response relationship of the thyroid for radiation-induced hypothyroidism in head-and-neck radiation therapy, according to 6 normal tissue complication probability models, and to find the best-fit parameters of the models. Methods and Materials: Sixty-five patients treated with primary or postoperative radiation therapy for various cancers in the head-and-neck region were prospectively evaluated. Patient serum samples (tri-iodothyronine, thyroxine, thyroid-stimulating hormone [TSH], free tri-iodothyronine, and free thyroxine) were measured before and at regular time intervals until 1 year after the completion of radiation therapy. Dose-volume histograms (DVHs) of the patients' thyroid gland were derived from their computed tomography (CT)-based treatment planning data. Hypothyroidism was defined as increased TSH (subclinical hypothyroidism) or increased TSH in combination with decreased free thyroxine and thyroxine (clinical hypothyroidism). Thyroid DVHs were converted to 2 Gy/fraction equivalent doses using the linear-quadratic formula with {alpha}/{beta} = 3 Gy. The evaluated models included the following: Lyman with the DVH reduced to the equivalent uniform dose (EUD), known as LEUD; Logit-EUD; mean dose; relative seriality; individual critical volume; and population critical volume models. The parameters of the models were obtained by fitting the patients' data using a maximum likelihood analysis method. The goodness of fit of the models was determined by the 2-sample Kolmogorov-Smirnov test. Ranking of the models was made according to Akaike's information criterion. Results: Twenty-nine patients (44.6%) experienced hypothyroidism. None of the models was rejected according to the evaluation of the goodness of fit. The mean dose model was ranked as the best model on the basis of its Akaike's information criterion value. The D{sub 50} estimated from the models was approximately 44 Gy. Conclusions: The implemented

  11. Integrating deterministic lithostratigraphic models in stochastic realizations of subsurface heterogeneity. Impact on predictions of lithology, hydraulic heads and groundwater fluxes

    Science.gov (United States)

    Bianchi, Marco; Kearsey, Timothy; Kingdon, Andrew

    2015-12-01

    Realistic representations of geological complexity are important to address several engineering and environmental challenges. The spatial distribution of properties controlling physical and geochemical processes can be effectively described by the geological structure of the subsurface. In this work, we present an approach to account for geological structure in geostatistical simulations of categorical variables. The approach is based on the extraction of information from a deterministic conceptualization of the subsurface, which is then used in the geostatistical analysis for the development of models of spatial correlation and as soft conditioning data. The approach was tested to simulate the distribution of four lithofacies in highly heterolithic Quaternary deposits. A transition probability-based stochastic model was implemented using hard borehole data and soft data extracted from a 3-D deterministic lithostratigraphic model. Simulated lithofacies distributions were also used as input in a flow model for numerical simulation of hydraulic head and groundwater flux. The outputs from these models were compared to corresponding values from models based exclusively on borehole data. Results show that soft lithostratigraphic information increases the accuracy and reduces the uncertainty of these predictions. The representation of the geological structure also allows a more precise definition of the spatial distribution of prediction uncertainty, here quantified with a metric based on Shannon information entropy. Correlations between prediction uncertainties for lithofacies, hydraulic heads and groundwater fluxes were also investigated. The results from this analysis provide useful insights about the incorporation of soft geological data into stochastic realizations of subsurface heterogeneity, and emphasize the critical importance of this type of information for reducing the uncertainty of simulations considering flux-dependent processes.

  12. Safety evaluation report on Westinghouse Electric Company ECCS evaluation model for plants equipped with upper head injection

    International Nuclear Information System (INIS)

    Lauben, G.N.; Wagner, N.H.; Israel, S.L.; McPherson, G.D.; Hodges, M.W.

    1978-04-01

    For plants which include an ice condenser containment concept, Westinghouse has planned an additional safety system known as the upper head injection (UHI) system to augment the emergency core cooling system. This system is comprised of additional accumulator tanks and piping arranged to supply cooling water to the top of the core during the blowdown period following a postulated large-break loss-of-coolant accident (LOCA). The objective of UHI is to add to the core cooling provided by the conventional emergency core cooling system (ECCS) and so permit operation at linear heat rates comparable to those permitted in plants utilizing the dry containment concept. In this way, plants which include the UHI system would have greater operating flexibility while still meeting the acceptance criteria as defined in paragraph 50.46 of 10 CFR Part 50. This review is concerned with those changes to the Westinghouse ECCS evaluation model that have been proposed for the UHI-LOCA model

  13. Using Monte Carlo modelling in optimising treatment outcome in advanced head and neck cancers treated with chemoradiotherapy

    International Nuclear Information System (INIS)

    Marcu, L.G.; Bezak, E.

    2011-01-01

    Full text: Advanced head and neck cancers are highly aggressive therefore they require corresponding treatment. Alterations in radiotherapy fractionation are possible ways to improve tumour control. However, while radiotherapy alone has an impact on the short term prognosis, long-term benefits are only moderate. Chemotherapy, whether concurrent or neoadjuvant, offers a possible way to improve treatment outcome. A Monte Carlo model was developed to demonstrate the role of cisplatin in altered fractionation radiotherapy and to develop a less customary schedule for neoadjuvant chemotherapy. Cisplatin combined with conventional radiotherapy was shown to improve patient survival. A Monte Carlo model was developed to assess the effect of combined cisplatin-altered fractionation schedule on a virtual head and neck tumour. Radiotherapy was simulated using the linear-quadratic formalism, whereas the cisplatin model was based on experimental data. Various neoadjuvant schedules were designed for cisplatin to optimize therapeutic ratio without increasing normal tissue toxicity. Concurrent daily cisplatin + altered fractionated radiotherapy have a notable effect on repopulation: while a TCP of 97.9% is reached with 60 Gy accelerated radiotherapy, the same TCP is achieved with daily cisplatin + 26 Gy accelerated radiotherapy (43% of the dose). Neoadjuvant cisplatin administered every third day leads to the same cell kill as daily cisplatin but with lower tissue toxicity. Conclusions Cisplatin both concurrently and prior to radiation offer superior tumour control as compared to radiation alone. Whilst the model outcome is valid for a small tumour (5 x 106 cells) the results can be extrapolated to obtain equivalent data for a clinically detectable tumour.

  14. Validation of CRASH Model in Prediction of 14-day Mortality and 6-month Unfavorable Outcome of Head Trauma Patients

    Directory of Open Access Journals (Sweden)

    Behrooz Hashemi

    2016-08-01

    Full Text Available Introduction: To date, many prognostic models have been proposed to predict the outcome of patients withtraumatic brain injuries. External validation of these models in different populations is of great importancefor their generalization. The present study was designed, aiming to determine the value of CRASH prognosticmodel in prediction of 14-day mortality (14-DM and 6-month unfavorable outcome (6-MUO of patients withtraumatic brain injury. Methods: In the present prospective diagnostic test study, calibration and discriminationof CRASH model were evaluated in head trauma patients referred to the emergency department. Variablesrequired for calculating CRASH expected risks (ER, and observed 14-DM and 6-MUO were gathered. Then ERof 14-DM and 6-MUO were calculated. The patients were followed for 6 months and their 14-DM and 6-MUOwere recorded. Finally, the correlation of CRASH ER and the observed outcome of the patients was evaluated.The data were analyzed using STATA version 11.0. Results: In this study, 323 patients with the mean age of 34.0´s 19.4 years were evaluated (87.3% male. Calibration of the basic and CT models in prediction of 14-day and6-month outcome were in the desirable range (P Ç 0.05. Area under the curve in the basic model for predictionof 14-DM and 6-MUO were 0.92 (95% CI: 0.89–0.96 and 0.92 (95% CI: 0.90–0.95, respectively. In addition,area under the curve in the CT model for prediction of 14-DM and 6-MUO were 0.93 (95% CI: 0.91–0.97 and0.93 (95% CI: 0.91–0.96, respectively. There was no significant difference between the discriminations of thetwo models in prediction of 14-DM (p Æ 0.11 and 6-MUO (p Æ 0.1. Conclusion: The results of the presentstudy showed that CRASH prediction model has proper discrimination and calibration in predicting 14-DMand6-MUO of head trauma patients. Since there was no difference between the values of the basic and CT models,using the basic model is recommended to simplify the risk

  15. Westinghouse Electric Company ECCS, Upper Head Injection evaluation model conformance to 10CFR50, appendix K

    International Nuclear Information System (INIS)

    1976-08-01

    The review presented is concerned with those changes to the Westinghouse ECCS evaluation model that have been proposed for the UHI-LOCA model. The objective is to establish that the UHI-LOCA model is in conformance with 10CFR50, Appendix K. The report includes the complete NRC staff assessment to date of the UHI-LOCA evaluation model

  16. The effect of numbered heads together (NHT) cooperative learning model on the cognitive achievement of students with different academic ability

    Science.gov (United States)

    Leasa, Marleny; Duran Corebima, Aloysius

    2017-01-01

    Learning models and academic ability may affect students’ achievement in science. This study, thus aimed to investigate the effect of numbered heads together (NHT) cooperative learning model on elementary students’ cognitive achievement in natural science. This study employed a quasi-experimental design with pretest-posttest non-equivalent control group with 2 x 2 factorial. There were two learning models compared NHT and the conventional, and two academic ability high and low. The results of ana Cova test confirmed the difference in the students’ cognitive achievement based on learning models and general academic ability. However, the interaction between learning models and academic ability did not affect the students’ cognitive achievement. In conclusion, teachers are strongly recommended to be more creative in designing learning using other types of cooperative learning models. Also, schools are required to create a better learning environment which is more cooperative to avoid unfair competition among students in the classroom and as a result improve the students’ academic ability. Further research needs to be conducted to explore the contribution of other aspects in cooperative learning toward cognitive achievement of students with different academic ability.

  17. Algorithm development and simulation outcomes for hypoxic head and neck cancer radiotherapy using a Monte Carlo cell division model

    International Nuclear Information System (INIS)

    Harriss, W.M.; Bezak, E.; Yeoh, E.

    2010-01-01

    Full text: A temporal Monte Carlo tumour model, 'Hyp-RT'. sim ulating hypoxic head and neck cancer has been updated and extended to model radiothcrapy. The aim is to providc a convenient radiobio logical tool for clinicians to evaluate radiotherapy treatment schedules based on many individual tumour properties including oxygenation. FORTRAN95 and JA YA havc been utilised to develop the efficient algorithm, which can propagate 108 cells. Epithelial cell kill is affected by dose, oxygenation and proliferativc status. Accelerated repopulation (AR) has been modelled by increasing the symmetrical stem cell division probability, and reoxygenation (ROx) has been modelled using random incremental boosts of oxygen to the cell po ulation throughout therapy. Results The stem cell percentage and the degree of hypoxia dominate tumour growth rate. For conventional radiotherapy. 15-25% more dose was required for a hypox ic versus oxic tumours, depending on the time of AR onset (0-3 weeks after thc start of treatment). ROx of hypoxic tumours resulted in tumoUJ: sensitisation and therefore a dose reduction, of up to 35%, varying with the time of onset. Fig. I shows results for all combinations of AR and ROx onset times for the moderate hypoxia case. Conclusions In hypoxic tumours, accelerated repopulation and reoxy genation affect ccll kill in the same manner as when the effects are modelled individually. however the degree of the effect is altered and therefore the combined result is difficult to predict. providing evidence for the usefulness of computer models. Simulations have quantitatively

  18. Regional electric field induced by electroconvulsive therapy in a realistic finite element head model: influence of white matter anisotropic conductivity.

    Science.gov (United States)

    Lee, Won Hee; Deng, Zhi-De; Kim, Tae-Seong; Laine, Andrew F; Lisanby, Sarah H; Peterchev, Angel V

    2012-02-01

    We present the first computational study investigating the electric field (E-field) strength generated by various electroconvulsive therapy (ECT) electrode configurations in specific brain regions of interest (ROIs) that have putative roles in the therapeutic action and/or adverse side effects of ECT. This study also characterizes the impact of the white matter (WM) conductivity anisotropy on the E-field distribution. A finite element head model incorporating tissue heterogeneity and WM anisotropic conductivity was constructed based on structural magnetic resonance imaging (MRI) and diffusion tensor MRI data. We computed the spatial E-field distributions generated by three standard ECT electrode placements including bilateral (BL), bifrontal (BF), and right unilateral (RUL) and an investigational electrode configuration for focal electrically administered seizure therapy (FEAST). The key results are that (1) the median E-field strength over the whole brain is 3.9, 1.5, 2.3, and 2.6 V/cm for the BL, BF, RUL, and FEAST electrode configurations, respectively, which coupled with the broad spread of the BL E-field suggests a biophysical basis for observations of superior efficacy of BL ECT compared to BF and RUL ECT; (2) in the hippocampi, BL ECT produces a median E-field of 4.8 V/cm that is 1.5-2.8 times stronger than that for the other electrode configurations, consistent with the more pronounced amnestic effects of BL ECT; and (3) neglecting the WM conductivity anisotropy results in E-field strength error up to 18% overall and up to 39% in specific ROIs, motivating the inclusion of the WM conductivity anisotropy in accurate head models. This computational study demonstrates how the realistic finite element head model incorporating tissue conductivity anisotropy provides quantitative insight into the biophysics of ECT, which may shed light on the differential clinical outcomes seen with various forms of ECT, and may guide the development of novel stimulation paradigms

  19. Incorporating single-side sparing in models for predicting parotid dose sparing in head and neck IMRT

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Lulin, E-mail: lulin.yuan@duke.edu; Wu, Q. Jackie; Yin, Fang-Fang; Yoo, David [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Jiang, Yuliang [Department of Radiation Oncology, Peking University Third Hospital, Beijing, China, 100191 (China); Ge, Yaorong [Department of Software and Information Systems, University of North Carolina at Charlotte, Charlotte, North Carolina 28223 (United States)

    2014-02-15

    Purpose: Sparing of single-side parotid gland is a common practice in head-and-neck (HN) intensity modulated radiation therapy (IMRT) planning. It is a special case of dose sparing tradeoff between different organs-at-risk. The authors describe an improved mathematical model for predicting achievable dose sparing in parotid glands in HN IMRT planning that incorporates single-side sparing considerations based on patient anatomy and learning from prior plan data. Methods: Among 68 HN cases analyzed retrospectively, 35 cases had physician prescribed single-side parotid sparing preferences. The single-side sparing model was trained with cases which had single-side sparing preferences, while the standard model was trained with the remainder of cases. A receiver operating characteristics (ROC) analysis was performed to determine the best criterion that separates the two case groups using the physician's single-side sparing prescription as ground truth. The final predictive model (combined model) takes into account the single-side sparing by switching between the standard and single-side sparing models according to the single-side sparing criterion. The models were tested with 20 additional cases. The significance of the improvement of prediction accuracy by the combined model over the standard model was evaluated using the Wilcoxon rank-sum test. Results: Using the ROC analysis, the best single-side sparing criterion is (1) the predicted median dose of one parotid is higher than 24 Gy; and (2) that of the other is higher than 7 Gy. This criterion gives a true positive rate of 0.82 and a false positive rate of 0.19, respectively. For the bilateral sparing cases, the combined and the standard models performed equally well, with the median of the prediction errors for parotid median dose being 0.34 Gy by both models (p = 0.81). For the single-side sparing cases, the standard model overestimates the median dose by 7.8 Gy on average, while the predictions by the combined

  20. Electromagnetic Head-And-Neck Hyperthermia Applicator: Experimental Phantom Verification and FDTD Model

    International Nuclear Information System (INIS)

    Paulides, Margarethus M.; Bakker, Jurriaan F.; Rhoon, Gerard C. van

    2007-01-01

    Purpose: To experimentally verify the feasibility of focused heating in the neck region by an array of two rings of six electromagnetic antennas. We also measured the dynamic specific absorption rate (SAR) steering possibilities of this setup and compared these SAR patterns to simulations. Methods and Materials: Using a specially constructed laboratory prototype head-and-neck applicator, including a neck-mimicking cylindrical muscle phantom, we performed SAR measurements by electric field, Schottky-diode sheet measurements and, using the power-pulse technique, by fiberoptic thermometry and infrared thermography. Using phase steering, we also steered the SAR distribution in radial and axial directions. All measured distributions were compared with the predictions by a finite-difference time-domain-based electromagnetic simulator. Results: A central 50% iso-SAR focus of 35 ± 3 mm in diameter and about 100 ± 15 mm in length was obtained for all investigated settings. Furthermore, this SAR focus could be steered toward the desired location in the radial and axial directions with an accuracy of ∼5 mm. The SAR distributions as measured by all three experimental methods were well predicted by the simulations. Conclusion: The results of our study have shown that focused heating in the neck is feasible and that this focus can be effectively steered in the radial and axial directions. For quality assurance measurements, we believe that the Schottky-diode sheet provides the best compromise among effort, speed, and accuracy, although a more specific and improved design is warranted

  1. A New Model for Predicting Acute Mucosal Toxicity in Head-and-Neck Cancer Patients Undergoing Radiotherapy With Altered Schedules

    International Nuclear Information System (INIS)

    Strigari, Lidia; Pedicini, Piernicola; D’Andrea, Marco; Pinnarò, Paola; Marucci, Laura; Giordano, Carolina; Benassi, Marcello

    2012-01-01

    Purpose: One of the worst radiation-induced acute effects in treating head-and-neck (HN) cancer is grade 3 or higher acute (oral and pharyngeal) mucosal toxicity (AMT), caused by the killing/depletion of mucosa cells. Here we aim to testing a predictive model of the AMT in HN cancer patients receiving different radiotherapy schedules. Methods and Materials: Various radiotherapeutic schedules have been reviewed and classified as tolerable or intolerable based on AMT severity. A modified normal tissue complication probability (NTCP) model has been investigated to describe AMT data in radiotherapy regimens, both conventional and altered in dose and overall treatment time (OTT). We tested the hypothesis that such a model could also be applied to identify intolerable treatment and to predict AMT. This AMT NTCP model has been compared with other published predictive models to identify schedules that are either tolerable or intolerable. The area under the curve (AUC) was calculated for all models, assuming treatment tolerance as the gold standard. The correlation between AMT and the predicted toxicity rate was assessed by a Pearson correlation test. Results: The AMT NTCP model was able to distinguish between acceptable and intolerable schedules among the data available for the study (AUC = 0.84, 95% confidence interval = 0.75-0.92). In the equivalent dose at 2 Gy/fraction (EQD2) vs OTT space, the proposed model shows a trend similar to that of models proposed by other authors, but was superior in detecting some intolerable schedules. Moreover, it was able to predict the incidence of ≥G3 AMT. Conclusion: The proposed model is able to predict ≥G3 AMT after HN cancer radiotherapy, and could be useful for designing altered/hypofractionated schedules to reduce the incidence of AMT.

  2. Impact of uncertainty description on assimilating hydraulic head in the MIKE SHE distributed hydrological model

    DEFF Research Database (Denmark)

    Zhang, Donghua; Madsen, Henrik; Ridler, Marc E.

    2015-01-01

    The ensemble Kalman filter (EnKF) is a popular data assimilation (DA) technique that has been extensively used in environmental sciences for combining complementary information from model predictions and observations. One of the major challenges in EnKF applications is the description of model un...... with respect to performance and sensitivity. Results show that inappropriate definition of model uncertainty can greatly degrade the assimilation performance, and an appropriate combination of different model uncertainty sources is advised....

  3. Cost reduction of the head stack assembly process in the hard disk drive industry with simulation modeling and optimization: A case study

    Directory of Open Access Journals (Sweden)

    Supawan Srithip

    2017-10-01

    Full Text Available This research with the main goal of cost reduction in the hard disk drive industry focused on the head stack assembly process is action research between university research teams and industry. It aims to study the head stack assembly process and to investigate the problems that need to be solved in order to reduce costs by using computer simulations and optimizations. Steps in simulation methodology were applied starting from data collection, model building, model verification, model validation, experimentation, and optimization. Several factors and their effects were investigated that could lead to production improvement of 7.94% increase in numbers of assembled head stack or 7.32% decrease in production cycle time. This paper demonstrates simulation optimization methodology applied to problem solving. Also it illustrates the successful case of using simulation optimization in cost reduction.

  4. Development and validation of a numerical model of the swine head subjected to open-field blasts

    Science.gov (United States)

    Kalra, A.; Zhu, F.; Feng, K.; Saif, T.; Kallakuri, S.; Jin, X.; Yang, K.; King, A.

    2017-11-01

    A finite element model of the head of a 55-kg Yucatan pig was developed to calculate the incident pressure and corresponding intracranial pressure due to the explosion of 8 lb (3.63 kg) of C4 at three different distances. The results from the model were validated by comparing findings with experimentally obtained data from five pigs at three different blast overpressure levels: low (150 kPa), medium (275 kPa), and high (400 kPa). The peak values of intracranial pressures from numerical model at different locations of the brain such as the frontal, central, left temporal, right temporal, parietal, and occipital regions were compared with experimental values. The model was able to predict the peak pressure with reasonable percentage differences. The differences for peak incident and intracranial pressure values between the simulation results and the experimental values were found to be less than 2.2 and 29.3%, respectively, at all locations other than the frontal region. Additionally, a series of parametric studies shows that the intracranial pressure was very sensitive to sensor locations, the presence of air bubbles, and reflections experienced during the experiments. Further efforts will be undertaken to correlate the different biomechanical response parameters, such as the intracranial pressure gradient, stress, and strain results obtained from the validated model with injured brain locations once the histology data become available.

  5. CT-based patient modeling for head and neck hyperthermia treatment planning: Manual versus automatic normal-tissue-segmentation

    International Nuclear Information System (INIS)

    Verhaart, René F.; Fortunati, Valerio; Verduijn, Gerda M.; Walsum, Theo van; Veenland, Jifke F.; Paulides, Margarethus M.

    2014-01-01

    Background and purpose: Clinical trials have shown that hyperthermia, as adjuvant to radiotherapy and/or chemotherapy, improves treatment of patients with locally advanced or recurrent head and neck (H and N) carcinoma. Hyperthermia treatment planning (HTP) guided H and N hyperthermia is being investigated, which requires patient specific 3D patient models derived from Computed Tomography (CT)-images. To decide whether a recently developed automatic-segmentation algorithm can be introduced in the clinic, we compared the impact of manual- and automatic normal-tissue-segmentation variations on HTP quality. Material and methods: CT images of seven patients were segmented automatically and manually by four observers, to study inter-observer and intra-observer geometrical variation. To determine the impact of this variation on HTP quality, HTP was performed using the automatic and manual segmentation of each observer, for each patient. This impact was compared to other sources of patient model uncertainties, i.e. varying gridsizes and dielectric tissue properties. Results: Despite geometrical variations, manual and automatic generated 3D patient models resulted in an equal, i.e. 1%, variation in HTP quality. This variation was minor with respect to the total of other sources of patient model uncertainties, i.e. 11.7%. Conclusions: Automatically generated 3D patient models can be introduced in the clinic for H and N HTP

  6. Head Injuries

    Science.gov (United States)

    ... numbness in the arms or legs. Loss of consciousness. Seizures. What causes a head injury? There are ... Aid and Injury Prevention Crisis Situations Pets and Animals myhealthfinder Food and Nutrition Healthy Food Choices Weight ...

  7. Head Lice

    Science.gov (United States)

    ... Head lice cannot jump or fly. Only the direct contact with an infested person or their contaminated ... the complex world of health care and making…Sports and Exercise at Every AgeRead Article >>Exercise and ...

  8. The effectiveness of a head-heart-hands model for natural and environmental science learning in urban schools.

    Science.gov (United States)

    Jagannathan, Radha; Camasso, Michael J; Delacalle, Maia

    2018-02-01

    We describe an environmental and natural science program called Nurture thru Nature (NtN) that seeks to improve mathematics and science performance of students in disadvantaged communities, and to increase student interest in Science, Technology, Engineering and Mathematics (STEM) careers. The program draws conceptual guidance from the Head-Heart-Hands model that informs the current educational movement to foster environmental understanding and sustainability. Employing an experimental design and data from seven cohorts of students, we find some promising, albeit preliminary, indications that the program can increase students' science knowledge and grades in mathematics, science and language arts. We discuss the special adaptations that environmental and sustainability education programs need to incorporate if they are to be successful in today's resource depleted urban schools. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. An Efficient Algorithm for EM Scattering from Anatomically Realistic Human Head Model Using Parallel CG-FFT Method

    Directory of Open Access Journals (Sweden)

    Lei Zhao

    2014-01-01

    Full Text Available An efficient algorithm is proposed to analyze the electromagnetic scattering problem from a high resolution head model with pixel data format. The algorithm is based on parallel technique and the conjugate gradient (CG method combined with the fast Fourier transform (FFT. Using the parallel CG-FFT method, the proposed algorithm is very efficient and can solve very electrically large-scale problems which cannot be solved using the conventional CG-FFT method in a personal computer. The accuracy of the proposed algorithm is verified by comparing numerical results with analytical Mie-series solutions for dielectric spheres. Numerical experiments have demonstrated that the proposed method has good performance on parallel efficiency.

  10. Evaluating habitat suitability models for nesting white-headed woodpeckers in unburned forest

    Science.gov (United States)

    Quresh S. Latif; Victoria A. Saab; Kim Mellen-Mclean; Jonathan G. Dudley

    2015-01-01

    Habitat suitability models can provide guidelines for species conservation by predicting where species of interest are likely to occur. Presence-only models are widely used but typically provide only relative indices of habitat suitability (HSIs), necessitating rigorous evaluation often using independently collected presence-absence data. We refined and evaluated...

  11. Quantifying the Dynamics of Field Cancerization in Tobacco-Related Head and Neck Cancer: A Multiscale Modeling Approach.

    Science.gov (United States)

    Ryser, Marc D; Lee, Walter T; Ready, Neal E; Leder, Kevin Z; Foo, Jasmine

    2016-12-15

    High rates of local recurrence in tobacco-related head and neck squamous cell carcinoma (HNSCC) are commonly attributed to unresected fields of precancerous tissue. Because they are not easily detectable at the time of surgery without additional biopsies, there is a need for noninvasive methods to predict the extent and dynamics of these fields. Here, we developed a spatial stochastic model of tobacco-related HNSCC at the tissue level and calibrated the model using a Bayesian framework and population-level incidence data from the Surveillance, Epidemiology, and End Results (SEER) registry. Probabilistic model analyses were performed to predict the field geometry at time of diagnosis, and model predictions of age-specific recurrence risks were tested against outcome data from SEER. The calibrated models predicted a strong dependence of the local field size on age at diagnosis, with a doubling of the expected field diameter between ages at diagnosis of 50 and 90 years, respectively. Similarly, the probability of harboring multiple, clonally unrelated fields at the time of diagnosis was found to increase substantially with patient age. On the basis of these findings, we hypothesized a higher recurrence risk in older than in younger patients when treated by surgery alone; we successfully tested this hypothesis using age-stratified outcome data. Further clinical studies are needed to validate the model predictions in a patient-specific setting. This work highlights the importance of spatial structure in models of epithelial carcinogenesis and suggests that patient age at diagnosis may be a critical predictor of the size and multiplicity of precancerous lesions. Cancer Res; 76(24); 7078-88. ©2016 AACR. ©2016 American Association for Cancer Research.

  12. A stylized computational model of the head for the reference Japanese male

    International Nuclear Information System (INIS)

    Yamauchi, M.; Ishikawa, M.; Hoshi, M.

    2005-01-01

    Computational models of human anatomy, along with Monte Carlo radiation transport simulations, have been used by Snyder et al. [MIRD Pamphlet No. 5, revised (The Society of Nuclear Medicine, New York, 1978)], Cristy and Eckerman [ORNL/TM-8381/VI, Oak Ridge National Laboratory, Oak Ridge, TN (1987)] and Zubal et al. [Med. Phys. 21, 299-302 (1994)] to estimate internal organ doses from internal and external radiation sources. These were created using physiological data from Caucasoid subjects but not from other races. There is a need for research to determine whether the obvious differences from the Caucasoid anatomy make these models unsuitable for estimating the absorbed dose in other races such as the Mongoloid. We used the cranial region of the adult Japanese male to represent the Mongoloid race. This region contains organs that are highly sensitive to radiation. The cranial region of a physical phantom produced by KYOTO KAGAKU Co., LTD. using numerical data from a Japanese Reference Man [Tanaka, Nippon Acta. Radiol. 48, 509-513 (1988)] was used to supply the data for the geometry of a stylized computational model. Our computational model was constructed with equations rather than voxel-based, in order to deal with as small a number of parameters as possible in the computer simulation experiment. The accuracy of our computational model was checked by comparing simulated experimental results obtained with MCNP4C with actual doses measured with thermoluminescence dosimeters (TLDs) inside the physical phantom from which our computational model was constructed. The TLDs, whose margin of error is less than ±10%, were arranged at six positions. Co-60 was used as the radiation source. The irradiated dose was 2 Gy in terms of air kerma. In the computer simulation experiments, we used our computational model and Cristy's computational model, whose component data are those of the tissue substitute materials and of the human body as published in ICRU Report 46. The

  13. Underbody Blast Models of TBI Caused by Hyper-Acceleration and Secondary Head Impact

    Science.gov (United States)

    2017-10-01

    society meeting, San Francisco, CA (05/16) “Translational Research in Traumatic Brain Injury: The Basic Scientist’s Perspective” 4. Johns Hopkins...personnel carriers when a buried explosive detonates beneath them.7,8 Adaptation and scaling of this model to allow animal injury in a similar explosive...of 10, based on buried explosions of different intensities.54 Experiments with full scale models of military vehicles indicate that land mines generate

  14. Neuroimmune mechanisms of behavioral alterations in a syngeneic murine model of human papilloma virus-related head and neck cancer.

    Science.gov (United States)

    Vichaya, Elisabeth G; Vermeer, Daniel W; Christian, Diana L; Molkentine, Jessica M; Mason, Kathy A; Lee, John H; Dantzer, Robert

    2017-05-01

    Patients with cancer often experience a high symptom burden prior to the start of treatment. As disease- and treatment-related neurotoxicities appear to be additive, targeting disease-related symptoms may attenuate overall symptom burden for cancer patients and improve the tolerability of treatment. It has been hypothesized that disease-related symptoms are a consequence of tumor-induced inflammation. We tested this hypothesis using a syngeneic heterotopic murine model of human papilloma virus (HPV)-related head and neck cancer. This model has the advantage of being mildly aggressive and not causing cachexia or weight loss. We previously showed that this tumor leads to increased IL-6, IL-1β, and TNF-α expression in the liver and increased IL-1β expression in the brain. The current study confirmed these features and demonstrated that the tumor itself exhibits high inflammatory cytokine expression (e.g., IL-6, IL-1β, and TNF-α) compared to healthy tissue. While there is a clear relationship between cytokine levels and behavioral deficits in this model, the behavioral changes are surprisingly mild. Therefore, we sought to confirm the relationship between behavior and inflammation by amplifying the effect using a low dose of lipopolysaccharide (LPS, 0.1mg/kg). In tumor-bearing mice LPS induced deficits in nest building, tail suspension, and locomotor activity approximately 24h after LPS. However, these mice did not display an exacerbation of LPS-induced weight loss, anorexia, or anhedonia. Further, while heightened serum IL-6 was observed there was minimal priming of liver or brain cytokine expression. Next we sought to inhibit tumor-induced burrowing deficits by reducing inflammation using minocycline. Minocycline (∼50mg/kg/day in drinking water) was able to attenuate tumor-induced inflammation and burrowing deficits. These data provide evidence in favor of an inflammatory-like mechanism for the behavioral alterations associated with tumor growth in a syngeneic

  15. Numerical models for the analysis of thermal behavior and coolability of a particulate debris bed in reactor lower head

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Kwang Il; Kim, Sang Baik; Kim, Byung Seok [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2002-04-01

    This report provides three distinctive, but closely related numerical models developed for the analysis of thermal behavior and coolability of a particulate debris bed that is may be formed inside the reactor lower head during severe accident late phases. The first numerical module presented in the report, MELTPRO-DRY, is used to analyze numerically heat-up and melting process of the dry particle bed, downward- and sideward-relocation of the liquid melt under gravity force and capillary force acting among porous particles, and solidification of the liquid melt relocated into colder region. The second module, MELTPROG-WET, is used to simulate numerically the cooling process of the particulate debris bed under the existence of water, which is subjected to two types of numerical models. The first type of WET module utilizes distinctive models that parametrically simulate the water cooling process, that is, quenching region, dryout region, and transition region. The choice of each parametric model depends on temperature gradient between the cooling water and the debris particles. The second type of WET module utilizes two-phase flow model that mechanically simulates the cooling process of the debris bed. For a consistent simulation from the water cooling to the dryout debris bed, on the other hand, the aforementioned two modules, MELTPROG-DRY and MELTPROG-WET, were integrated into a single computer program DBCOOL. Each of computational models was verified through limited applications to a heat-generating particulate bed contained in the rectangular cavity. 22 refs., 5 figs., 2 tabs. (Author)

  16. Automated MRI segmentation for individualized modeling of current flow in the human head

    Science.gov (United States)

    Huang, Yu; Dmochowski, Jacek P.; Su, Yuzhuo; Datta, Abhishek; Rorden, Christopher; Parra, Lucas C.

    2013-12-01

    Objective. High-definition transcranial direct current stimulation (HD-tDCS) and high-density electroencephalography require accurate models of current flow for precise targeting and current source reconstruction. At a minimum, such modeling must capture the idiosyncratic anatomy of the brain, cerebrospinal fluid (CSF) and skull for each individual subject. Currently, the process to build such high-resolution individualized models from structural magnetic resonance images requires labor-intensive manual segmentation, even when utilizing available automated segmentation tools. Also, accurate placement of many high-density electrodes on an individual scalp is a tedious procedure. The goal was to develop fully automated techniques to reduce the manual effort in such a modeling process. Approach. A fully automated segmentation technique based on Statical Parametric Mapping 8, including an improved tissue probability map and an automated correction routine for segmentation errors, was developed, along with an automated electrode placement tool for high-density arrays. The performance of these automated routines was evaluated against results from manual segmentation on four healthy subjects and seven stroke patients. The criteria include segmentation accuracy, the difference of current flow distributions in resulting HD-tDCS models and the optimized current flow intensities on cortical targets.Main results. The segmentation tool can segment out not just the brain but also provide accurate results for CSF, skull and other soft tissues with a field of view extending to the neck. Compared to manual results, automated segmentation deviates by only 7% and 18% for normal and stroke subjects, respectively. The predicted electric fields in the brain deviate by 12% and 29% respectively, which is well within the variability observed for various modeling choices. Finally, optimized current flow intensities on cortical targets do not differ significantly.Significance. Fully

  17. The Autonomous-collaborative Care Model: meeting the future head on.

    Science.gov (United States)

    LeClerc, Chantale Marie; Doyon, Julie; Gravelle, Debbie; Hall, Bonnie; Roussel, Josette

    2008-01-01

    As care needs continue to increase in complexity in inpatient settings, and nurses' scope of practice evolves to keep pace with these changing demands, it is imperative that nurse leaders ensure nursing care delivery models are well aligned to current realities. Older, traditional models of nursing service may no longer foster safe, effective and efficient care or contribute to job satisfaction and high-quality work life for nurses. This paper describes the Autonomous-Collaborative Care Model and its application in a continuing care setting. This innovative and flexible model fosters autonomy and accountability in nursing practice, reduces duplication in the execution of nursing tasks, enhances effective communication and outlines mechanisms for collaboration among various members of the nursing and interprofessional teams. The model has positioned the authors' organization to meet impending shortages of nursing personnel by ensuring that the right category of nurse is assigned to the appropriate patient, by reducing non-nursing work and by supporting nurses' autonomy to practise to their full scope.

  18. A predictive model for swallowing dysfunction after curative radiotherapy in head and neck cancer

    NARCIS (Netherlands)

    Langendijk, Johannes A.; Doornaert, Patricia; Rietveld, Derek H. F.; Verdonck-de Leeuw, Irma M.; Leemans, C. Rene; Slotman, Ben J.

    Introduction: Recently, we found that swallowing dysfunction after curative (chemo) radiation (CH) RT has a strong negative impact on health-related quality of life (HRQoL), even more than xerostomia. The purpose of this study was to design a predictive model for swallowing dysfunction after

  19. A predictive model for swallowing dysfunction after curative radiotherapy in head and neck cancer.

    NARCIS (Netherlands)

    Langendijk, J.A.; Doornaert, P.A.H.; Rietveld, D.H.F.; de Leeuw, I.M.; Leemans, C.R.; Slotman, B.J.

    2009-01-01

    Introduction: Recently, we found that swallowing dysfunction after curative (chemo) radiation (CH) RT has a strong negative impact on health-related quality of life (HRQoL), even more than xerostomia. The purpose of this study was to design a predictive model for swallowing dysfunction after

  20. Follow the heart or the head? The interactive influence model of emotion and cognition

    Science.gov (United States)

    Luo, Jiayi; Yu, Rongjun

    2015-01-01

    The experience of emotion has a powerful influence on daily-life decision making. Following Plato’s description of emotion and reason as two horses pulling us in opposite directions, modern dual-system models of decision making endorse the antagonism between reason and emotion. Decision making is perceived as the competition between an emotion system that is automatic but prone to error and a reason system that is slow but rational. The reason system (in “the head”) reins in our impulses (from “the heart”) and overrides our snap judgments. However, from Darwin’s evolutionary perspective, emotion is adaptive, guiding us to make sound decisions in uncertainty. Here, drawing findings from behavioral economics and neuroeconomics, we provide a new model, labeled “The interactive influence model of emotion and cognition,” to elaborate the relationship of emotion and reason in decision making. Specifically, in our model, we identify factors that determine when emotions override reason and delineate the type of contexts in which emotions help or hurt decision making. We then illustrate how cognition modulates emotion and how they cooperate to affect decision making. PMID:25999889

  1. A heads-up no-limit Texas Hold'em poker player: Discretized betting models and automatically generated equilibrium-finding programs

    DEFF Research Database (Denmark)

    Gilpin, Andrew G.; Sandholm, Tuomas; Sørensen, Troels Bjerre

    2008-01-01

    We present Tartanian, a game theory-based player for heads-up no-limit Texas Hold'em poker. Tartanian is built from three components. First, to deal with the virtually infinite strategy space of no-limit poker, we develop a discretized betting model designed to capture the most important strategic...

  2. Functional Data Analysis Applied to Modeling of Severe Acute Mucositis and Dysphagia Resulting From Head and Neck Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Dean, Jamie A., E-mail: jamie.dean@icr.ac.uk [Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London (United Kingdom); Wong, Kee H. [Head and Neck Unit, The Royal Marsden NHS Foundation Trust, London (United Kingdom); Gay, Hiram [Department of Radiation Oncology, School of Medicine, Washington University in St Louis, St Louis, Missouri (United States); Welsh, Liam C.; Jones, Ann-Britt; Schick, Ulrike [Head and Neck Unit, The Royal Marsden NHS Foundation Trust, London (United Kingdom); Oh, Jung Hun; Apte, Aditya [Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York (United States); Newbold, Kate L.; Bhide, Shreerang A.; Harrington, Kevin J. [Head and Neck Unit, The Royal Marsden NHS Foundation Trust, London (United Kingdom); Division of Radiotherapy and Imaging, The Institute of Cancer Research, London (United Kingdom); Deasy, Joseph O. [Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York (United States); Nutting, Christopher M. [Head and Neck Unit, The Royal Marsden NHS Foundation Trust, London (United Kingdom); Division of Radiotherapy and Imaging, The Institute of Cancer Research, London (United Kingdom); Gulliford, Sarah L. [Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London (United Kingdom)

    2016-11-15

    Purpose: Current normal tissue complication probability modeling using logistic regression suffers from bias and high uncertainty in the presence of highly correlated radiation therapy (RT) dose data. This hinders robust estimates of dose-response associations and, hence, optimal normal tissue–sparing strategies from being elucidated. Using functional data analysis (FDA) to reduce the dimensionality of the dose data could overcome this limitation. Methods and Materials: FDA was applied to modeling of severe acute mucositis and dysphagia resulting from head and neck RT. Functional partial least squares regression (FPLS) and functional principal component analysis were used for dimensionality reduction of the dose-volume histogram data. The reduced dose data were input into functional logistic regression models (functional partial least squares–logistic regression [FPLS-LR] and functional principal component–logistic regression [FPC-LR]) along with clinical data. This approach was compared with penalized logistic regression (PLR) in terms of predictive performance and the significance of treatment covariate–response associations, assessed using bootstrapping. Results: The area under the receiver operating characteristic curve for the PLR, FPC-LR, and FPLS-LR models was 0.65, 0.69, and 0.67, respectively, for mucositis (internal validation) and 0.81, 0.83, and 0.83, respectively, for dysphagia (external validation). The calibration slopes/intercepts for the PLR, FPC-LR, and FPLS-LR models were 1.6/−0.67, 0.45/0.47, and 0.40/0.49, respectively, for mucositis (internal validation) and 2.5/−0.96, 0.79/−0.04, and 0.79/0.00, respectively, for dysphagia (external validation). The bootstrapped odds ratios indicated significant associations between RT dose and severe toxicity in the mucositis and dysphagia FDA models. Cisplatin was significantly associated with severe dysphagia in the FDA models. None of the covariates was significantly associated with severe

  3. Principal component analysis-based anatomical motion models for use in adaptive radiation therapy of head and neck cancer patients

    Science.gov (United States)

    Chetvertkov, Mikhail A.

    Purpose: To develop standard and regularized principal component analysis (PCA) models of anatomical changes from daily cone beam CTs (CBCTs) of head and neck (H&N) patients, assess their potential use in adaptive radiation therapy (ART), and to extract quantitative information for treatment response assessment. Methods: Planning CT (pCT) images of H&N patients were artificially deformed to create "digital phantom" images, which modeled systematic anatomical changes during Radiation Therapy (RT). Artificial deformations closely mirrored patients' actual deformations, and were interpolated to generate 35 synthetic CBCTs, representing evolving anatomy over 35 fractions. Deformation vector fields (DVFs) were acquired between pCT and synthetic CBCTs (i.e., digital phantoms), and between pCT and clinical CBCTs. Patient-specific standard PCA (SPCA) and regularized PCA (RPCA) models were built from these synthetic and clinical DVF sets. Eigenvectors, or eigenDVFs (EDVFs), having the largest eigenvalues were hypothesized to capture the major anatomical deformations during treatment. Modeled anatomies were used to assess the dose deviations with respect to the planned dose distribution. Results: PCA models achieve variable results, depending on the size and location of anatomical change. Random changes prevent or degrade SPCA's ability to detect underlying systematic change. RPCA is able to detect smaller systematic changes against the background of random fraction-to-fraction changes, and is therefore more successful than SPCA at capturing systematic changes early in treatment. SPCA models were less successful at modeling systematic changes in clinical patient images, which contain a wider range of random motion than synthetic CBCTs, while the regularized approach was able to extract major modes of motion. For dose assessment it has been shown that the modeled dose distribution was different from the planned dose for the parotid glands due to their shrinkage and shift into

  4. Functional Data Analysis Applied to Modeling of Severe Acute Mucositis and Dysphagia Resulting From Head and Neck Radiation Therapy

    International Nuclear Information System (INIS)

    Dean, Jamie A.; Wong, Kee H.; Gay, Hiram; Welsh, Liam C.; Jones, Ann-Britt; Schick, Ulrike; Oh, Jung Hun; Apte, Aditya; Newbold, Kate L.; Bhide, Shreerang A.; Harrington, Kevin J.; Deasy, Joseph O.; Nutting, Christopher M.; Gulliford, Sarah L.

    2016-01-01

    Purpose: Current normal tissue complication probability modeling using logistic regression suffers from bias and high uncertainty in the presence of highly correlated radiation therapy (RT) dose data. This hinders robust estimates of dose-response associations and, hence, optimal normal tissue–sparing strategies from being elucidated. Using functional data analysis (FDA) to reduce the dimensionality of the dose data could overcome this limitation. Methods and Materials: FDA was applied to modeling of severe acute mucositis and dysphagia resulting from head and neck RT. Functional partial least squares regression (FPLS) and functional principal component analysis were used for dimensionality reduction of the dose-volume histogram data. The reduced dose data were input into functional logistic regression models (functional partial least squares–logistic regression [FPLS-LR] and functional principal component–logistic regression [FPC-LR]) along with clinical data. This approach was compared with penalized logistic regression (PLR) in terms of predictive performance and the significance of treatment covariate–response associations, assessed using bootstrapping. Results: The area under the receiver operating characteristic curve for the PLR, FPC-LR, and FPLS-LR models was 0.65, 0.69, and 0.67, respectively, for mucositis (internal validation) and 0.81, 0.83, and 0.83, respectively, for dysphagia (external validation). The calibration slopes/intercepts for the PLR, FPC-LR, and FPLS-LR models were 1.6/−0.67, 0.45/0.47, and 0.40/0.49, respectively, for mucositis (internal validation) and 2.5/−0.96, 0.79/−0.04, and 0.79/0.00, respectively, for dysphagia (external validation). The bootstrapped odds ratios indicated significant associations between RT dose and severe toxicity in the mucositis and dysphagia FDA models. Cisplatin was significantly associated with severe dysphagia in the FDA models. None of the covariates was significantly associated with severe

  5. Functional Data Analysis Applied to Modeling of Severe Acute Mucositis and Dysphagia Resulting From Head and Neck Radiation Therapy.

    Science.gov (United States)

    Dean, Jamie A; Wong, Kee H; Gay, Hiram; Welsh, Liam C; Jones, Ann-Britt; Schick, Ulrike; Oh, Jung Hun; Apte, Aditya; Newbold, Kate L; Bhide, Shreerang A; Harrington, Kevin J; Deasy, Joseph O; Nutting, Christopher M; Gulliford, Sarah L

    2016-11-15

    Current normal tissue complication probability modeling using logistic regression suffers from bias and high uncertainty in the presence of highly correlated radiation therapy (RT) dose data. This hinders robust estimates of dose-response associations and, hence, optimal normal tissue-sparing strategies from being elucidated. Using functional data analysis (FDA) to reduce the dimensionality of the dose data could overcome this limitation. FDA was applied to modeling of severe acute mucositis and dysphagia resulting from head and neck RT. Functional partial least squares regression (FPLS) and functional principal component analysis were used for dimensionality reduction of the dose-volume histogram data. The reduced dose data were input into functional logistic regression models (functional partial least squares-logistic regression [FPLS-LR] and functional principal component-logistic regression [FPC-LR]) along with clinical data. This approach was compared with penalized logistic regression (PLR) in terms of predictive performance and the significance of treatment covariate-response associations, assessed using bootstrapping. The area under the receiver operating characteristic curve for the PLR, FPC-LR, and FPLS-LR models was 0.65, 0.69, and 0.67, respectively, for mucositis (internal validation) and 0.81, 0.83, and 0.83, respectively, for dysphagia (external validation). The calibration slopes/intercepts for the PLR, FPC-LR, and FPLS-LR models were 1.6/-0.67, 0.45/0.47, and 0.40/0.49, respectively, for mucositis (internal validation) and 2.5/-0.96, 0.79/-0.04, and 0.79/0.00, respectively, for dysphagia (external validation). The bootstrapped odds ratios indicated significant associations between RT dose and severe toxicity in the mucositis and dysphagia FDA models. Cisplatin was significantly associated with severe dysphagia in the FDA models. None of the covariates was significantly associated with severe toxicity in the PLR models. Dose levels greater than

  6. Premedication with meloxicam exacerbates intracranial hemorrhage in an immature swine model of non-impact inertial head injury

    Science.gov (United States)

    Friess, SH; Naim, MY; Kilbaugh, TJ; Ralston, J; Margulies, SS

    2014-01-01

    Meloxicam is a cyclo-oxgenase-2 preferential non-steroid anti-inflammatory drug with very effective analgesic and anti-inflammatory effects in swine. Previous reports in piglets have demonstrated that meloxicam also inhibits cyclo-oxgenase-1 and reduces production of thromboxane significantly. We use pre-injury analgesia in our immature swine (3–5 day old piglets) model of brain injury using rapid head rotations without impact. In 23 consecutive subjects we found that premedication with meloxicam (N=6) produced a significantly higher mortality rate (5/6 or 83%) than buprenorphine (N =17, 1/17 or 6%, p meloxicam-treated swine, we observed massive subdural and subarachnoid bleeding which were not present in buprenorphine-premedicated animals. To our knowledge there are no previous reports in swine of increased bleeding or platelet inhibition associated with meloxicam administration and further research is needed to define mechanisms of action in piglets. We caution the use of meloxicam in swine when inhibition of platelet aggregation might adversely affect refinement of experimental research protocols, such as in stroke, trauma, and cardiac arrest models. PMID:22238292

  7. Head Tilt

    Science.gov (United States)

    ... bones in the neck. Children with Klippel-Feil syndrome may have a short, broad neck, low hairline, and very restricted neck movement. Torticollis ... surgery may be necessary. To treat Klippel-Feil syndrome, a specialist may recommend ... to ease head and neck pain. Your pediatrician can refer you to a ...

  8. Head lice

    OpenAIRE

    Burgess, Ian F

    2011-01-01

    Head lice can only be diagnosed by finding live lice, as eggs take 7 days to hatch, and may appear viable for weeks after death of the egg. Infestation may be more likely in school children, with risks increased in children with more siblings, longer hair, or of lower socioeconomic group.

  9. Evaluation of 3-dimensional superimposition techniques on various skeletal structures of the head using surface models.

    Directory of Open Access Journals (Sweden)

    Nikolaos Gkantidis

    Full Text Available To test the applicability, accuracy, precision, and reproducibility of various 3D superimposition techniques for radiographic data, transformed to triangulated surface data.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.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 (D0.05, 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.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 the present study population, the BZ superimposition was comparable to AC, with the added advantage of being applicable to scans with a smaller field of view.

  10. Evaluation of 3-dimensional superimposition techniques on various skeletal structures of the head using surface models.

    Science.gov (United States)

    Gkantidis, Nikolaos; Schauseil, Michael; Pazera, Pawel; Zorkun, Berna; Katsaros, Christos; Ludwig, Björn

    2015-01-01

    To test the applicability, accuracy, precision, and reproducibility of various 3D superimposition techniques for radiographic data, transformed to triangulated surface data. 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. 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 (D0.05), 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. 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 the present study population, the BZ superimposition was comparable to AC, with the added advantage of being applicable to scans with a smaller field of view.

  11. Is HEADS in our heads?

    DEFF Research Database (Denmark)

    Boisen, Kirsten A; Hertz, Pernille Grarup; Blix, Charlotte

    2016-01-01

    BACKGROUND: Outpatient clinic visits are a window of opportunity to address health risk behaviors and promote a healthier lifestyle among young people. The HEADS (Home, Education, Eating, Activities, Drugs [i.e. substance use including tobacco, alcohol, and illegal drugs], Sexuality [including...... contraception], Safety, Self-harm) interview is a feasible way of exploring health risk behaviors and resilience. OBJECTIVE: The purpose of this study was to evaluate how often HEADS topics were addressed according to young patients and staff in pediatric and adult outpatient clinics. METHODS: We conducted...

  12. A Graphic Overlay Method for Selection of Osteotomy Site in Chronic Radial Head Dislocation: An Evaluation of 3D-printed Bone Models.

    Science.gov (United States)

    Kim, Hui Taek; Ahn, Tae Young; Jang, Jae Hoon; Kim, Kang Hee; Lee, Sung Jae; Jung, Duk Young

    2017-03-01

    Three-dimensional (3D) computed tomography imaging is now being used to generate 3D models for planning orthopaedic surgery, but the process remains time consuming and expensive. For chronic radial head dislocation, we have designed a graphic overlay approach that employs selected 3D computer images and widely available software to simplify the process of osteotomy site selection. We studied 5 patients (2 traumatic and 3 congenital) with unilateral radial head dislocation. These patients were treated with surgery based on traditional radiographs, but they also had full sets of 3D CT imaging done both before and after their surgery: these 3D CT images form the basis for this study. From the 3D CT images, each patient generated 3 sets of 3D-printed bone models: 2 copies of the preoperative condition, and 1 copy of the postoperative condition. One set of the preoperative models was then actually osteotomized and fixed in the manner suggested by our graphic technique. Arcs of rotation of the 3 sets of 3D-printed bone models were then compared. Arcs of rotation of the 3 groups of bone models were significantly different, with the models osteotomized accordingly to our graphic technique having the widest arcs. For chronic radial head dislocation, our graphic overlay approach simplifies the selection of the osteotomy site(s). Three-dimensional-printed bone models suggest that this approach could improve range of motion of the forearm in actual surgical practice. Level IV-therapeutic study.

  13. Crashworthiness Simulation of Front Bumper Model of MOROLIPI V2 During Head-on Collision

    Directory of Open Access Journals (Sweden)

    Nugraha Aditya Sukma

    2016-01-01

    Full Text Available It is necessary to conduct an impact test for bumper collision. The use of bumper as a protective components of a vehicle during collision. On this Paper, a crashworthiness simulation of front bumper model with correspond to the size of MOROLIPI V2 is conducted. The purpose of this study was to obtain simulation result used as a reference to predict mechanical behaviour of bumper due to collision. The Simulation result can be predicted deformation after collision, von misses stress criteria after collision with static dummy load. To simulate impact on bumper, ANSYS Explicit Dynamics is used. Simulations were run at three values of mobile robot speeds (5, 10 and 20 m/s. The simulation results also show contact force due to the collision, deformation, stress and internal energy of the bumper beam. It was known that the speed of the vehicle is the dominant parameter determine the results of the crashworthiness simulation.

  14. Modeling the dosimetry of organ-at-risk in head and neck IMRT planning: An intertechnique and interinstitutional study

    Energy Technology Data Exchange (ETDEWEB)

    Lian, Jun, E-mail: jun-lian@med.unc.edu; Chera, Bhishamjit S.; Chang, Sha [Department of Radiation Oncology, The University of North Carolina, Chapel Hill, North Carolina 27599 (United States); Yuan, Lulin, E-mail: lulin.yuan@duke.edu; Yoo, David P.; Yin, FangFang; Wu, Q. Jackie, E-mail: jackie.wu@duke.edu [Department of Radiation Oncology, Duke University, Durham, North Carolina 27710 (United States); Ge, Yaorong [Department of Software and Information Systems, The University of North Carolina, Charlotte, North Carolina 28223 (United States)

    2013-12-15

    Purpose: To build a statistical model to quantitatively correlate the anatomic features of structures and the corresponding dose-volume histogram (DVH) of head and neck (HN) Tomotherapy (Tomo) plans. To study if the model built upon one intensity modulated radiation therapy (IMRT) technique (such as conventional Linac) can be used to predict anticipated organs-at-risk (OAR) DVH of patients treated with a different IMRT technique (such as Tomo). To study if the model built upon the clinical experience of one institution can be used to aid IMRT planning for another institution. Methods: Forty-four Tomotherapy intensity modulate radiotherapy plans of HN cases (Tomo-IMRT) from Institution A were included in the study. A different patient group of 53 HN fixed gantry IMRT (FG-IMRT) plans was selected from Institution B. The analyzed OARs included the parotid, larynx, spinal cord, brainstem, and submandibular gland. Two major groups of anatomical features were considered: the volumetric information and the spatial information. The volume information includes the volume of target, OAR, and overlapped volume between target and OAR. The spatial information of OARs relative to PTVs was represented by the distance-to-target histogram (DTH). Important anatomical and dosimetric features were extracted from DTH and DVH by principal component analysis. Two regression models, one for Tomotherapy plan and one for IMRT plan, were built independently. The accuracy of intratreatment-modality model prediction was validated by a leave one out cross-validation method. The intertechnique and interinstitution validations were performed by using the FG-IMRT model to predict the OAR dosimetry of Tomo-IMRT plans. The dosimetry of OARs, under the same and different institutional preferences, was analyzed to examine the correlation between the model prediction and planning protocol. Results: Significant patient anatomical factors contributing to OAR dose sparing in HN Tomotherapy plans have been

  15. Discussion on "Modeling karst spring hydrograph recession based on head drop at sinkholes" by Guangquan, Li, Nico Goldscheider, Malcom S. Field

    Science.gov (United States)

    Şen, Zekâi

    2018-02-01

    Groundwater movement model development in karstic aquifers is very difficult due to the complexity of the solution cavities. The authors (Li et al., 2016) have proposed a square law model for expressing the discharge ratio in terms of hydraulic head ratio, with an exponent equal to 0.5. They have also provided the mathematical derivation in detail with application. It is noticed that the methodology can be expanded towards a better and refined solutions by consideration of the following explanations.

  16. Robust Sub-harmonic Mixer at 340 GHz Using Intrinsic Resonances of Hammer-Head Filter and Improved Diode Model

    Science.gov (United States)

    Wang, Cheng; He, Yue; Lu, Bin; Jiang, Jun; Miao, Li; Deng, Xian-Jin; Xiong, Yong-zhong; Zhang, Jian

    2017-11-01

    This paper presents a sub-harmonic mixer at 340 GHz based on anti-parallel Schottky diodes (SBDs). Intrinsic resonances in low-pass hammer-head filter have been adopted to enhance the isolation for different harmonic components, while greatly minimizing the transmission loss. The application of new DC grounding structure, impedance matching structure, and suspended micro-strip mitigates the negative influences of fabrication errors from metal cavity, quartz substrate, and micro-assembly. An improved lumped element equivalent circuit model of SBDs guarantees the accuracy of simulation, which takes current-voltage (I/V) behavior, capacitance-voltage (C/V) behavior, carrier velocity saturation, DC series resistor, plasma resonance, skin effect, and four kinds of noise generation mechanisms into consideration thoroughly. The measurement indicates that with local oscillating signal of 2 mW, the lowest double sideband conversion loss is 5.5 dB at 339 GHz; the corresponding DSB noise temperature is 757 K. The 3 dB bandwidth of conversion loss is 50 GHz from 317 to 367 GHz.

  17. Adaptive radiotherapy with an average anatomy model: Evaluation and quantification of residual deformations in head and neck cancer patients

    International Nuclear Information System (INIS)

    Kranen, Simon van; Mencarelli, Angelo; Beek, Suzanne van; Rasch, Coen; Herk, Marcel van; Sonke, Jan-Jakob

    2013-01-01

    Background and purpose: To develop and validate an adaptive intervention strategy for radiotherapy of head-and-neck cancer that accounts for systematic deformations by modifying the planning-CT (pCT) to the average misalignments in daily cone beam CT (CBCT) measured with deformable registration (DR). Methods and materials: Daily CBCT scans (808 scans) for 25 patients were retrospectively registered to the pCT with B-spline DR. The average deformation vector field ( ) was used to deform the pCT for adaptive intervention. Two strategies were simulated: single intervention after 10 fractions and weekly intervention with an from the previous week. The model was geometrically validated with the residual misalignment of anatomical landmarks both on bony-anatomy (BA; automatically generated) and soft-tissue (ST; manually identified). Results: Systematic deformations were 2.5/3.4 mm vector length (BA/ST). Single intervention reduced deformations to 1.5/2.7 mm (BA/ST). Weekly intervention resulted in 1.0/2.2 mm (BA/ST) and accounted better for progressive changes. 15 patients had average systematic deformations >2 mm (BA): reductions were 1.1/1.9 mm (single/weekly BA). ST improvements were underestimated due to observer and registration variability. Conclusions: Adaptive intervention with a pCT modified to the average anatomy during treatment successfully reduces systematic deformations. The improved accuracy could possibly be exploited in margin reduction and/or dose escalation

  18. Targeting TORC1/2 Enhances Sensitivity to EGFR Inhibitors in Head and Neck Cancer Preclinical Models

    Directory of Open Access Journals (Sweden)

    Andre Cassell

    2012-11-01

    Full Text Available Head and neck squamous cell carcinoma (HNSCC is characterized by overexpression of the epidermal growth factor receptor (EGFR where treatments targeting EGFR have met with limited clinical success. Elucidation of the key downstream-pathways that remain activated in the setting of EGFR blockade may reveal new therapeutic targets. The present study was undertaken to test the hypothesis that inhibition of the mammalian target of rapamycin (mTOR complex would enhance the effects of EGFR blockade in HNSCC preclinical models. Treatment of HNSCC cell lines with the newly developed TORC1/TORC2 inhibitor OSI-027/ASP4876 resulted in dose-dependent inhibition of proliferation with abrogation of phosphorylation of known downstream targets including phospho-AKT (Ser473, phospho-4E-BP1, phospho-p70s6K, and phospho-PRAS40. Furthermore, combined treatment with OSI-027 and erlotinib resulted in enhanced biochemical effects and synergistic growth inhibition in vitro. Treatment of mice bearing HNSCC xenografts with a combination of the Food and Drug Administration (FDA-approved EGFR inhibitor cetuximab and OSI-027 demonstrated a significant reduction of tumor volumes compared with either treatment alone. These findings suggest that TORC1/TORC2 inhibition in conjunction with EGFR blockade represents a plausible therapeutic strategy for HNSCC.

  19. Targeting TORC1/2 enhances sensitivity to EGFR inhibitors in head and neck cancer preclinical models.

    Science.gov (United States)

    Cassell, Andre; Freilino, Maria L; Lee, Jessica; Barr, Sharon; Wang, Lin; Panahandeh, Mary C; Thomas, Sufi M; Grandis, Jennifer R

    2012-11-01

    Head and neck squamous cell carcinoma (HNSCC) is characterized by overexpression of the epidermal growth factor receptor (EGFR) where treatments targeting EGFR have met with limited clinical success. Elucidation of the key downstream-pathways that remain activated in the setting of EGFR blockade may reveal new therapeutic targets. The present study was undertaken to test the hypothesis that inhibition of the mammalian target of rapamycin (mTOR) complex would enhance the effects of EGFR blockade in HNSCC preclinical models. Treatment of HNSCC cell lines with the newly developed TORC1/TORC2 inhibitor OSI-027/ASP4876 resulted in dose-dependent inhibition of proliferation with abrogation of phosphorylation of known downstream targets including phospho-AKT (Ser473), phospho-4E-BP1, phospho-p70s6K, and phospho-PRAS40. Furthermore, combined treatment with OSI-027 and erlotinib resulted in enhanced biochemical effects and synergistic growth inhibition in vitro. Treatment of mice bearing HNSCC xenografts with a combination of the Food and Drug Administration (FDA)-approved EGFR inhibitor cetuximab and OSI-027 demonstrated a significant reduction of tumor volumes compared with either treatment alone. These findings suggest that TORC1/TORC2 inhibition in conjunction with EGFR blockade represents a plausible therapeutic strategy for HNSCC.

  20. Targeting TORC1/2 Enhances Sensitivity to EGFR Inhibitors in Head and Neck Cancer Preclinical Models1

    Science.gov (United States)

    Cassell, Andre; Freilino, Maria L; Lee, Jessica; Barr, Sharon; Wang, Lin; Panahandeh, Mary C; Thomas, Sufi M; Grandis, Jennifer R

    2012-01-01

    Head and neck squamous cell carcinoma (HNSCC) is characterized by overexpression of the epidermal growth factor receptor (EGFR) where treatments targeting EGFR have met with limited clinical success. Elucidation of the key downstream-pathways that remain activated in the setting of EGFR blockade may reveal new therapeutic targets. The present study was undertaken to test the hypothesis that inhibition of the mammalian target of rapamycin (mTOR) complex would enhance the effects of EGFR blockade in HNSCC preclinical models. Treatment of HNSCC cell lines with the newly developed TORC1/TORC2 inhibitor OSI-027/ASP4876 resulted in dose-dependent inhibition of proliferation with abrogation of phosphorylation of known downstream targets including phospho-AKT (Ser473), phospho-4E-BP1, phospho-p70s6K, and phospho-PRAS40. Furthermore, combined treatment with OSI-027 and erlotinib resulted in enhanced biochemical effects and synergistic growth inhibition in vitro. Treatment of mice bearing HNSCC xenografts with a combination of the Food and Drug Administration (FDA)-approved EGFR inhibitor cetuximab and OSI-027 demonstrated a significant reduction of tumor volumes compared with either treatment alone. These findings suggest that TORC1/TORC2 inhibition in conjunction with EGFR blockade represents a plausible therapeutic strategy for HNSCC. PMID:23226094

  1. Eksperimentasi Model Numbered Heads Together Dengan Make a Match (Nht Mm) Dan Numbered Heads Together Dengan Bamboo Dancing (Nht Bd) Ditinjau Dari Kecerdasan Interpersonal

    OpenAIRE

    Dewi, Arianti Puspita; Kusmayadi, Tri Atmojo; Usodo, Budi

    2014-01-01

    The purposes of this research were to determine: (1) which students mathematics achievement would be better, student given NHT MM, NHT BD, or direct learning model, (2) which students mathematics achievement would be better, student with interpersonal intelligence of high, medium or low, (3) which students mathematics achievement would be better, student with interpersonal intelligence of high, medium, or low on each learning model, (4) which student mathematics achievement would be better, ...

  2. Application of a compressible flow solver and barotropic cavitation model for the evaluation of the suction head in a low specific speed centrifugal pump impeller channel

    International Nuclear Information System (INIS)

    Limbach, P; Müller, T; Skoda, R

    2015-01-01

    Commonly, for the simulation of cavitation in centrifugal pumps incompressible flow solvers with VOF kind cavitation models are applied. Since the source/sink terms of the void fraction transport equation are based on simplified bubble dynamics, empirical parameters may need to be adjusted to the particular pump operating point. In the present study a barotropic cavitation model, which is based solely on thermodynamic fluid properties and does not include any empirical parameters, is applied on a single flow channel of a pump impeller in combination with a time-explicit viscous compressible flow solver. The suction head curves (head drop) are compared to the results of an incompressible implicit standard industrial CFD tool and are predicted qualitatively correct by the barotropic model. (paper)

  3. Application of a compressible flow solver and barotropic cavitation model for the evaluation of the suction head in a low specific speed centrifugal pump impeller channel

    Science.gov (United States)

    Limbach, P.; Müller, T.; Skoda, R.

    2015-12-01

    Commonly, for the simulation of cavitation in centrifugal pumps incompressible flow solvers with VOF kind cavitation models are applied. Since the source/sink terms of the void fraction transport equation are based on simplified bubble dynamics, empirical parameters may need to be adjusted to the particular pump operating point. In the present study a barotropic cavitation model, which is based solely on thermodynamic fluid properties and does not include any empirical parameters, is applied on a single flow channel of a pump impeller in combination with a time-explicit viscous compressible flow solver. The suction head curves (head drop) are compared to the results of an incompressible implicit standard industrial CFD tool and are predicted qualitatively correct by the barotropic model.

  4. A GPU based high-resolution multilevel biomechanical head and neck model for validating deformable image registration

    Energy Technology Data Exchange (ETDEWEB)

    Neylon, J., E-mail: jneylon@mednet.ucla.edu; Qi, X.; Sheng, K.; Low, D. A.; Kupelian, P.; Santhanam, A. [Department of Radiation Oncology, University of California Los Angeles, 200 Medical Plaza, #B265, Los Angeles, California 90095 (United States); Staton, R.; Pukala, J.; Manon, R. [Department of Radiation Oncology, M.D. Anderson Cancer Center, Orlando, 1440 South Orange Avenue, Orlando, Florida 32808 (United States)

    2015-01-15

    Purpose: Validating the usage of deformable image registration (DIR) for daily patient positioning is critical for adaptive radiotherapy (RT) applications pertaining to head and neck (HN) radiotherapy. The authors present a methodology for generating biomechanically realistic ground-truth data for validating DIR algorithms for HN anatomy by (a) developing a high-resolution deformable biomechanical HN model from a planning CT, (b) simulating deformations for a range of interfraction posture changes and physiological regression, and (c) generating subsequent CT images representing the deformed anatomy. Methods: The biomechanical model was developed using HN kVCT datasets and the corresponding structure contours. The voxels inside a given 3D contour boundary were clustered using a graphics processing unit (GPU) based algorithm that accounted for inconsistencies and gaps in the boundary to form a volumetric structure. While the bony anatomy was modeled as rigid body, the muscle and soft tissue structures were modeled as mass–spring-damper models with elastic material properties that corresponded to the underlying contoured anatomies. Within a given muscle structure, the voxels were classified using a uniform grid and a normalized mass was assigned to each voxel based on its Hounsfield number. The soft tissue deformation for a given skeletal actuation was performed using an implicit Euler integration with each iteration split into two substeps: one for the muscle structures and the other for the remaining soft tissues. Posture changes were simulated by articulating the skeletal structure and enabling the soft structures to deform accordingly. Physiological changes representing tumor regression were simulated by reducing the target volume and enabling the surrounding soft structures to deform accordingly. Finally, the authors also discuss a new approach to generate kVCT images representing the deformed anatomy that accounts for gaps and antialiasing artifacts that may

  5. BCG immune activation reduces growth and angiogenesis in an in vitro model of head and neck squamous cell carcinoma.

    Science.gov (United States)

    Sánchez-Rodríguez, Carolina; Cruces, Keyliz Peraza; Riestra Ayora, Juan; Martín-Sanz, Eduardo; Sanz-Fernández, Ricardo

    2017-11-07

    Head and neck squamous cell carcinoma (HNSCC) is one of the most frequent cancers worldwide and is associated with poor survival and significant treatment morbidity. The immune profile in patients with HNSCC is immunosuppressive and presents cytokine-mediated adaptive immune responses, triggered apoptosis of T cells, and alterations in antigen processing machinery. Bacille Calmette-Guerin (BCG) immunotherapy has been used successfully as a treatment for several types of cancer. In the present study, we sought to determine the antitumor effect of soluble mediators from peripheral blood mononuclear immune cells (PBMCs) activated with BCG vaccine in a three-dimensional coculture model of HNSCC growth using FaDu hypopharynx carcinoma squamous cells. BCG activation of PBMCs led to an increase in CD4+ and CD8+ lymphocyte subsets concomitant with an elevation in the levels of the antitumor cytokines IL-6, TNF-α and IFN-γ, and a EGFR in FaDu cells. In addition, coculture with BCG-activated PBMCs reduced FaDu proliferation and increased cytotoxicity and apoptosis in parallel with an increase in caspase-3 activity and p53 expression. Finally, conditioned medium from BCG-activated PBMCs reduced the levels of the angiogenic factors vascular endothelial growth factor and angiopoietin-2 produced by human aortic endothelial cells (HAECs), and inhibited their proliferation and differentiation into capillary-like structures. Taken together, these results demonstrate that BCG vaccination induces antitumor responses in an HNSCC in vitro model and suggest that the BCG vaccine could be an effective alternative therapy for the treatment of HNSCC. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Use of anisotropic modelling in electrical impedance tomography: description of method and preliminary assessment of utility in imaging brain function in the adult human head.

    Science.gov (United States)

    Abascal, Juan-Felipe P J; Arridge, Simon R; Atkinson, David; Horesh, Raya; Fabrizi, Lorenzo; De Lucia, Marzia; Horesh, Lior; Bayford, Richard H; Holder, David S

    2008-11-01

    Electrical Impedance Tomography (EIT) is an imaging method which enables a volume conductivity map of a subject to be produced from multiple impedance measurements. It has the potential to become a portable non-invasive imaging technique of particular use in imaging brain function. Accurate numerical forward models may be used to improve image reconstruction but, until now, have employed an assumption of isotropic tissue conductivity. This may be expected to introduce inaccuracy, as body tissues, especially those such as white matter and the skull in head imaging, are highly anisotropic. The purpose of this study was, for the first time, to develop a method for incorporating anisotropy in a forward numerical model for EIT of the head and assess the resulting improvement in image quality in the case of linear reconstruction of one example of the human head. A realistic Finite Element Model (FEM) of an adult human head with segments for the scalp, skull, CSF, and brain was produced from a structural MRI. Anisotropy of the brain was estimated from a diffusion tensor-MRI of the same subject and anisotropy of the skull was approximated from the structural information. A method for incorporation of anisotropy in the forward model and its use in image reconstruction was produced. The improvement in reconstructed image quality was assessed in computer simulation by producing forward data, and then linear reconstruction using a sensitivity matrix approach. The mean boundary data difference between anisotropic and isotropic forward models for a reference conductivity was 50%. Use of the correct anisotropic FEM in image reconstruction, as opposed to an isotropic one, corrected an error of 24 mm in imaging a 10% conductivity decrease located in the hippocampus, improved localisation for conductivity changes deep in the brain and due to epilepsy by 4-17 mm, and, overall, led to a substantial improvement on image quality. This suggests that incorporation of anisotropy in

  7. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... Professions Site Index A-Z Computed Tomography (CT) - Head Computed tomography (CT) of the head uses special ... the Head? What is CT Scanning of the Head? Computed tomography, more commonly known as a CT ...

  8. Process modeling and ultra-precision machining technology development for flat reflectors using a diamond milling head

    Directory of Open Access Journals (Sweden)

    S. V. Grubyy

    2014-01-01

    Full Text Available In the short and medium perspective an essential development of ultra-precision machining and micromachining is expected. It concerns the ultra-precision equipment and processing technology for optical elements and components of machines and devices of different size and purpose. The paper reviews the literature references in the field concerned, investigates the results of national and international researches associated with development of computational models, which describe the process of ultra-precision machining and micromachining. The main objective of the computation models is the relationship between the operating condition parameters and process indicators, such as cutting forces and temperatures, wear and tool life.A significant disadvantage of the models presented in the literature references is their poor adaptation to a possible change in the input data and machining conditions. Usually, their using makes it possible to conduct design analysis of incorporated parameters interrelation, but it is quantitatively impossible to determine the process output parameters with changing machining conditions.One of examples to apply the ultra-precision machining is the plane reflectors made of aluminum alloy. They are used in space technology as a part of the radiative cooler. For such reflector a technology has been designed to provide machining with a diamond milling head on the ultra-precision CNC machine.The calculation part of the paper analyses the kinematic scheme of machining and presents a model to determine a cutting length for the particular surface type. In subsequent calculations the cutting length is treated as a parameter to calculate the tool wear, cutting force and temperature.The presented computational model enables us to determine the cutting forces and temperature on the rake and clearance surface. The calculation takes into account the radius of cutting edge and the wear on the clearance surface, which depends on the path

  9. Portable Wideband Microwave Imaging System for Intracranial Hemorrhage Detection Using Improved Back-projection Algorithm with Model of Effective Head Permittivity

    Science.gov (United States)

    Mobashsher, Ahmed Toaha; Mahmoud, A.; Abbosh, A. M.

    2016-02-01

    Intracranial hemorrhage is a medical emergency that requires rapid detection and medication to restrict any brain damage to minimal. Here, an effective wideband microwave head imaging system for on-the-spot detection of intracranial hemorrhage is presented. The operation of the system relies on the dielectric contrast between healthy brain tissues and a hemorrhage that causes a strong microwave scattering. The system uses a compact sensing antenna, which has an ultra-wideband operation with directional radiation, and a portable, compact microwave transceiver for signal transmission and data acquisition. The collected data is processed to create a clear image of the brain using an improved back projection algorithm, which is based on a novel effective head permittivity model. The system is verified in realistic simulation and experimental environments using anatomically and electrically realistic human head phantoms. Quantitative and qualitative comparisons between the images from the proposed and existing algorithms demonstrate significant improvements in detection and localization accuracy. The radiation and thermal safety of the system are examined and verified. Initial human tests are conducted on healthy subjects with different head sizes. The reconstructed images are statistically analyzed and absence of false positive results indicate the efficacy of the proposed system in future preclinical trials.

  10. PENERAPAN MODEL PEMBELAJARAN NUMBERED HEAD TOGETHER (NHT PADA SISWA KELAS V SD NEGERI 75 UJUNGPERO KECAMATAN SABBANGPARU KABUPATEN WAJO

    Directory of Open Access Journals (Sweden)

    Wahyuddin Wahyuddin

    2017-06-01

    Full Text Available Tujuan penelitian ini adalah untuk mendeskripsikan hasil belajar matematika dengan penerapan pembelajaran kooperatif tipe Numbered Head Together siswa Kelas V SD Negeri 75 Ujungpero Kecamatan Sabbangparu Kabupaten Wajo. Penelitian ini merupakan penelitian tindakan kelas (Classroom Action Research yang meliputi perencanaan, tindakan, observasi, dan refleksi yang selanjutnya tahap-tahap tersebut dirangkai pada siklus yang dilaksnakan pada siklus I dan siklus II. Subjek penelitian ini adalah siswa kelas V SD Negeri 75 Ujungpero Kecamatan Sabbangparu Kabupaten Wajo  Tahun ajaran 2015/2016 sebanyak 10 orang yang terdiri atas 7 perempuan dan 3 laki-laki, jenis data yang digunakan adalah data kuantitatif dan data kualitatif yang terdiri dari : hasil belajar dan angket observasi yang dikumpulkan dengan cara pemberian tes kepada siswa dan data tentang situasi pembelajaran saat pelaksanaan tindakan diperoleh melalui format observasi dengan teknik analisis data kuantitatif dan kualitatif. Hasil penelitian menunjukkan bahwa pembelajaran kooperatif tipe NHT cocok diterapkan pada siswa kelas V SD Negeri 75 Ujungpero Kecamatan Sabbangparu Kabupaten Wajo. Hal tersebut dapat dilihat dari meningkatnya hasil belajar siswa setelah diadakan pengembangan pembelajaran kooperatif tipe NHT, Hasil belajar yang diperoleh dari tes akhir siklus, pada akhir siklus I dengan skor rata-rata 64,50 dari skor ideal 100 dengan standar deviasi 14,03, sedangkan pada akhir siklus II dengan skor rata-rata 80 dari skor ideal 100 dengan standar deviasi 9,13, dan terjadi perubahan sikap siswa selama proses pembelajaran sesuai dengan hasil observasi yaitu dengan adanya penerapan model pembelajaran kooperatif tipe NHT dapat meningkatkan rasa percaya diri siswa untuk bertanya baik kepada guru maupun kepada temannya tentang materi yang tidak dimengerti serta dapat meningkatkan kehadiran siswa.

  11. EGFR targeted nanobody-photosensitizer conjugates for photodynamic therapy in a pre-clinical model of head and neck cancer.

    Science.gov (United States)

    van Driel, Pieter B A A; Boonstra, Martin C; Slooter, Maxime D; Heukers, Raimond; Stammes, Marieke A; Snoeks, Thomas J A; de Bruijn, Henriette S; van Diest, Paul J; Vahrmeijer, Alexander L; van Bergen En Henegouwen, Paul M P; van de Velde, Cornelis J H; Löwik, Clemens W G M; Robinson, Dominic J; Oliveira, Sabrina

    2016-05-10

    Photodynamic therapy (PDT) induces cell death through local light activation of a photosensitizer (PS) and has been used to treat head and neck cancers. Yet, common PS lack tumor specificity, which leads to collateral damage to normal tissues. Targeted delivery of PS via antibodies has pre-clinically improved tumor selectivity. However, antibodies have long half-lives and relatively poor tissue penetration, which could limit therapeutic efficacy and lead to long photosensitivity. Here, in this feasibility study, we evaluate at the pre-clinical level a recently introduced format of targeted PDT, which employs nanobodies as targeting agents and a water-soluble PS (IRDye700DX) that is traceable through optical imaging. In vitro, the PS solely binds to cells and induces phototoxicity on cells overexpressing the epidermal growth factor receptor (EGFR), when conjugated to the EGFR targeted nanobodies. To investigate whether this new format of targeted PDT is capable of inducing selective tumor cell death in vivo, PDT was applied on an orthotopic mouse tumor model with illumination at 1h post-injection of the nanobody-PS conjugates, as selected from quantitative fluorescence spectroscopy measurements. In parallel, and as a reference, PDT was applied with an antibody-PS conjugate, with illumination performed 24h post-injection. Importantly, EGFR targeted nanobody-PS conjugates led to extensive tumor necrosis (approx. 90%) and almost no toxicity in healthy tissues, as observed through histology 24h after PDT. Overall, results show that these EGFR targeted nanobody-PS conjugates are selective and able to induce tumor cell death in vivo. Additional studies are now needed to assess the full potential of this approach to improving PDT. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  12. Realistic head model design and 3D brain imaging of NIRS signals using audio stimuli on preterm neonates for intra-ventricular hemorrhage diagnosis.

    Science.gov (United States)

    Fournier, Marc; Mahmoudzadeh, Mahdi; Kazemi, Kamran; Kongolo, Guy; Dehaene-Lambertz, Ghislaine; Grebe, Reinhard; Wallois, Fabrice

    2012-01-01

    In this paper we propose an auditory stimulation and near infra-red spectroscopy (NIRS) hemodynamic changes acquisition protocol for preterm neonates. This study is designed to assess the specific characteristics of neurovascular coupling to auditory stimuli in healthy and ill neonate brains. The method could lead to clinical application in intra-ventricular hemorrhage (IVH) diagnosis along with other techniques such as EEG. We propose a realistic head model creation with all useful head structures and brain tissues including the neonate fontanel for more accurate results from NIRS signals modeling. We also design a 3D imaging tool for dynamic mapping and analysis of brain activation onto the cortex surface. Results show significant differences in oxy-hemoglobin between healthy neonates and subjects with IVH.

  13. Bray Head

    OpenAIRE

    Brocas, Samuel Frederick (Irish cityscape painter, watercolorist, and draftsman, 1792-1847)

    2008-01-01

    'A number of Martello towers were built around the coast of Ireland, especially along the east, from Millmount (Drogheda), to Bray, around Dublin Bay but also around Cork Harbour on the south coast. On the east coast, concentrated mainly around Dublin Bay, the towers were in line of sight of each other, providing the ability to communicate with one another, or warn of any incoming attacks.' (en.wikipedia.org/wiki/Martello_Tower#Ireland) 'Bray Head (Irish: Ceann Bre) is a hill and headland, of...

  14. Goniometer head

    International Nuclear Information System (INIS)

    Dzhazairov-Kakhramanov, V.; Berger, V.D.; Kadyrzhanov, K.K.; Zarifov, R.A.

    1994-01-01

    The goniometer head is an electromechanical instrument that performs the independent transfer of a testing sample on three coordinate axes (X, Y, Z) within limits of ±8 mm and independent rotation relative of these directions. The instrument comprises a sample holder, bellows component and three electrometer drives. The sample holder rotates around the axes X and Y, and is installed on the central arm which rotates around axis Z. One characteristic of this instrument is its independence which allows its use in any camera for researches in the field of radiation physics. 2 figs

  15. Human-Like Behavior Generation Based on Head-Arms Model for Robot Tracking External Targets and Body Parts.

    Science.gov (United States)

    Zhang, Zhijun; Beck, Aryel; Magnenat-Thalmann, Nadia

    2015-08-01

    Facing and pointing toward moving targets is a usual and natural behavior in daily life. Social robots should be able to display such coordinated behaviors in order to interact naturally with people. For instance, a robot should be able to point and look at specific objects. This is why, a scheme to generate coordinated head-arm motion for a humanoid robot with two degrees-of-freedom for the head and seven for each arm is proposed in this paper. Specifically, a virtual plane approach is employed to generate the analytical solution of the head motion. A quadratic program (QP)-based method is exploited to formulate the coordinated dual-arm motion. To obtain the optimal solution, a simplified recurrent neural network is used to solve the QP problem. The effectiveness of the proposed scheme is demonstrated using both computer simulation and physical experiments.

  16. Head-to-head comparison of health-state values derived by a probabilistic choice model and scores on a visual analogue scale.

    Science.gov (United States)

    Krabbe, Paul F M; Stolk, Elly A; Devlin, Nancy J; Xie, Feng; Quik, Elise H; Pickard, A Simon

    2017-11-01

    Health states were quantified based on discrete choice (DC) modeling and visual analogue scale (VAS) values using the five-level version of the EQ-5D (EQ-5D-5L). The aim of this study was to determine the extent of the relationship between DC derived values (indirect method) and VAS values (direct method). Data were collected in Canada, the United Kingdom, the Netherlands, and the United States. Respondents were asked to perform paired comparisons between two EQ-5D-5L health states for DC. In total, 400 different EQ-5D-5L states were included. After each DC task, respondents were prompted to score the two states one after another on a VAS. Intraclass correlation coefficients were calculated between DC and VAS values and illuminating graphs were designed. Approximately 400 respondents participated from each country. High similarity [individual intraclass correlation coefficients (ICC) >0.85] of DC and moderate correspondence of VAS values were observed for the four countries. Cross-country comparison of DC values shows a nonlinear relationship to the VAS values. EQ-5D-5L derived DC and VAS values show a close but nonlinear relationship. Given the obvious biases associated with the VAS, DC methods based on ordinal responses may be a better alternative.

  17. Species delineation using Bayesian model-based assignment tests: a case study using Chinese toad-headed agamas (genus Phrynocephalus

    Directory of Open Access Journals (Sweden)

    Fu Jinzhong

    2010-06-01

    Full Text Available Abstract Background Species are fundamental units in biology, yet much debate exists surrounding how we should delineate species in nature. Species discovery now requires the use of separate, corroborating datasets to quantify independently evolving lineages and test species criteria. However, the complexity of the speciation process has ushered in a need to infuse studies with new tools capable of aiding in species delineation. We suggest that model-based assignment tests are one such tool. This method circumvents constraints with traditional population genetic analyses and provides a novel means of describing cryptic and complex diversity in natural systems. Using toad-headed agamas of the Phrynocephalus vlangalii complex as a case study, we apply model-based assignment tests to microsatellite DNA data to test whether P. putjatia, a controversial species that closely resembles P. vlangalii morphologically, represents a valid species. Mitochondrial DNA and geographic data are also included to corroborate the assignment test results. Results Assignment tests revealed two distinct nuclear DNA clusters with 95% (230/243 of the individuals being assigned to one of the clusters with > 90% probability. The nuclear genomes of the two clusters remained distinct in sympatry, particularly at three syntopic sites, suggesting the existence of reproductive isolation between the identified clusters. In addition, a mitochondrial ND2 gene tree revealed two deeply diverged clades, which were largely congruent with the two nuclear DNA clusters, with a few exceptions. Historical mitochondrial introgression events between the two groups might explain the disagreement between the mitochondrial and nuclear DNA data. The nuclear DNA clusters and mitochondrial clades corresponded nicely to the hypothesized distributions of P. vlangalii and P. putjatia. Conclusions These results demonstrate that assignment tests based on microsatellite DNA data can be powerful tools

  18. Head-to-head comparison of dipyridamole, dobutamine and pacing stress echocardiography for the detection of myocardial ischemia in an animal model of coronary artery stenosis

    Directory of Open Access Journals (Sweden)

    A. Schmidt

    2001-07-01

    Full Text Available To compare the sensitivity of dipyridamole, dobutamine and pacing stress echocardiography for the detection of myocardial ischemia we produced a physiologically significant stenosis in the left circumflex artery of 14 open-chest dogs (range: 50 to 89% reduction in luminal diameter. In each study, dobutamine (5 to 40 µg kg-1 min-1 in 3-min stages and pacing (20 bpm increments, each 2 min, up to 260 bpm were performed randomly, and then followed by dipyridamole (up to 0.84 mg/kg over 10 min. The positivity of stress echocardiography tests was quantitatively determined by a significant (P<0.05 reduction of or failure to increase absolute and percent systolic wall thickening in the stenotic artery supplied wall, as compared to the opposite wall (areas related to the left anterior descending artery. Systolic and diastolic frozen images were analyzed off-line by two blinded observers in the control and stress conditions. The results showed that 1 the sensitivity of dobutamine, dipyridamole and pacing stress tests was 57, 57 and 36%, respectively; 2 in animals with positive tests, the mean percent change of wall thickening in left ventricular ischemic segments was larger in the pacing (-19 ± 11% and dipyridamole (-18 ± 16% tests as compared to dobutamine (-9 ± 6% (P = 0.05, but a similar mean reduction of wall thickening was observed when this variable was normalized to a control left ventricular segment (area related to the left anterior descending artery (pacing: -16 ± 7%; dipyridamole: -25 ± 16%; dobutamine: -26 ± 10%; not significant, and 3 a significant correlation was observed between magnitude of coronary stenosis and left ventricular segmental dysfunction induced by ischemia in dogs submitted to positive stress tests. We conclude that the dobutamine and dipyridamole stress tests showed identical sensitivities for the detection of myocardial ischemia in this one-vessel disease animal model with a wide range of left circumflex artery

  19. Electric field calculations in brain stimulation based on finite elements: an optimized processing pipeline for the generation and usage of accurate individual head models.

    Science.gov (United States)

    Windhoff, Mirko; Opitz, Alexander; Thielscher, Axel

    2013-04-01

    The need for realistic electric field calculations in human noninvasive brain stimulation is undisputed to more accurately determine the affected brain areas. However, using numerical techniques such as the finite element method (FEM) is methodologically complex, starting with the creation of accurate head models to the integration of the models in the numerical calculations. These problems substantially limit a more widespread application of numerical methods in brain stimulation up to now. We introduce an optimized processing pipeline allowing for the automatic generation of individualized high-quality head models from magnetic resonance images and their usage in subsequent field calculations based on the FEM. The pipeline starts by extracting the borders between skin, skull, cerebrospinal fluid, gray and white matter. The quality of the resulting surfaces is subsequently improved, allowing for the creation of tetrahedral volume head meshes that can finally be used in the numerical calculations. The pipeline integrates and extends established (and mainly free) software for neuroimaging, computer graphics, and FEM calculations into one easy-to-use solution. We demonstrate the successful usage of the pipeline in six subjects, including field calculations for transcranial magnetic stimulation and transcranial direct current stimulation. The quality of the head volume meshes is validated both in terms of capturing the underlying anatomy and of the well-shapedness of the mesh elements. The latter is crucial to guarantee the numerical robustness of the FEM calculations. The pipeline will be released as open-source, allowing for the first time to perform realistic field calculations at an acceptable methodological complexity and moderate costs. Copyright © 2011 Wiley Periodicals, Inc.

  20. EGFR targeted nanobody-photosensitizer conjugates for photodynamic therapy in a pre-clinical model of head and neck cancer

    NARCIS (Netherlands)

    Van Driel, Pieter B A A; Boonstra, Martin C.; Slooter, Maxime D.; Heukers, Raimond; Stammes, Marieke A.; Snoeks, Thomas J A; De Bruijn, Henriette S.; Van Diest, Paul J.; Vahrmeijer, Alexander L.; Van Bergen En Henegouwen, Paul M P; Van De Velde, Cornelis J H; Löwik, Clemens W G M; Robinson, Dominic J.; Oliveira, Sabrina

    2016-01-01

    Photodynamic therapy (PDT) induces cell death through local light activation of a photosensitizer (PS) and has been used to treat head and neck cancers. Yet, common PS lack tumor specificity, which leads to collateral damage to normal tissues. Targeted delivery of PS via antibodies has

  1. Investigations into Hypoxia and Oxidative Stress at the Optic Nerve Head in a Rat Model of Glaucoma

    Directory of Open Access Journals (Sweden)

    Glyn Chidlow

    2017-08-01

    Full Text Available The vascular hypothesis of glaucoma proposes that retinal ganglion cell axons traversing the optic nerve head (ONH undergo oxygen and nutrient insufficiency as a result of compromised local blood flow, ultimately leading to their degeneration. To date, evidence for the hypothesis is largely circumstantial. Herein, we made use of an induced rat model of glaucoma that features reproducible and widespread axonal transport disruption at the ONH following chronic elevation of intraocular pressure. If vascular insufficiency plays a role in the observed axonal transport failure, there should exist a physical signature at this time point. Using a range of immunohistochemical and molecular tools, we looked for cellular events indicative of vascular insufficiency, including the presence of hypoxia, upregulation of hypoxia-inducible, or antioxidant-response genes, alterations to antioxidant enzymes, increased formation of superoxide, and the presence of oxidative stress. Our data show that ocular hypertension caused selective hypoxia within the laminar ONH in 11/13 eyes graded as either medium or high for axonal transport disruption. Hypoxia was always present in areas featuring injured axons, and, the greater the abundance of axonal transport disruption, the greater the likelihood of a larger hypoxic region. Nevertheless, hypoxic regions were typically focal and were not necessarily evident in sections taken deeper within the same ONH, while disrupted axonal transport was frequently encountered without any discernible hypoxia. Ocular hypertension caused upregulation of heme oxygenase-1—an hypoxia-inducible and redox-sensitive enzyme—in ONH astrocytes. The distribution and abundance of heme oxygenase-1 closely matched that of axonal transport disruption, and encompassed hypoxic regions and their immediate penumbra. Ocular hypertension also caused upregulations in the iron-regulating protein ceruloplasmin, the anaerobic glycolytic enzyme lactate

  2. Using an Empirical Model of Human Turning Motion to Aid Heading Estimation in a Personal Navigation System

    Science.gov (United States)

    Jakel, Thomas

    With the adoption of Global Navigation Satellite Systems in smart phones, soldier equipment, and emergency responder navigation systems users have realized the usefulness of low cost Personal Navigation Systems. The state-of-the-art Personal Navigation System is a unit that fuses information based on external references with a low cost IMU. Due to the size, weight, power, and cost constraints imposed on a pedestrian navigation systems as well as current IMU performance limitations, the gyroscopes used to determine heading exhibit significant drift limiting the performance of the navigation system. In this thesis biomechanical signals are used to predict the onset of pedestrian turning motion. Experimental data from eight subjects captured in a gait laboratory using a Vicon motion tracking unit is used for validation. The analysis of experimental data shows the heading computed by turn prediction augmented integration is more accurate than open loop gyro integration alone.

  3. Prediction of Acute Radiation Mucositis using an Oral Mucosal Dose Surface Model in Carbon Ion Radiotherapy for Head and Neck Tumors.

    Directory of Open Access Journals (Sweden)

    Atsushi Musha

    Full Text Available To evaluate the dose-response relationship for development of acute radiation mucositis (ARM using an oral mucosal dose surface model (OMDS-model in carbon ion radiotherapy (C-ion RT for head and neck tumors.Thirty-nine patients receiving C-ion RT for head and neck cancer were evaluated for ARM (once per week for 6 weeks according to the Common Terminology Criteria for Adverse Events (CTCAE, version 4.0, and the Radiation Therapy Oncology Group (RTOG scoring systems. The irradiation schedule typically used was 64 Gy [relative biological effectiveness (RBE] in 16 fractions for 4 weeks. Maximum point doses in the palate and tongue were compared with ARM in each patient.The location of the ARM coincided with the high-dose area in the OMDS-model. There was a clear dose-response relationship between maximum point dose and ARM grade assessed using the RTOG criteria but not the CTCAE. The threshold doses for grade 2-3 ARM in the palate and tongue were 43.0 Gy(RBE and 54.3 Gy(RBE, respectively.The OMDS-model was useful for predicting the location and severity of ARM. Maximum point doses in the model correlated well with grade 2-3 ARM.

  4. Caspase-3 may be employed as an early predictor for fracture‑induced osteonecrosis of the femoral head in a canine model.

    Science.gov (United States)

    Gao, You-Shui; Guo, Shang-Chun; Ding, Hao; Zhang, Chang-Qing

    2012-09-01

    The aim of the current study was to investigate the local expression of caspase-3 following femoral neck fractures in a canine model and to investigate its effect on the occurrence of fracture-induced osteonecrosis of the femoral head (ONFH). Eight dogs had surgically-induced femoral neck fractures on the left side which remained untreated. Radiological and histological examinations were employed to detect morphological changes of the femoral head. Immunohistochemical staining of caspase-3 was used to evaluate cell apoptosis, which may play an important role in ONFH. The results were compared to the normal side for statistical analysis. As a result, all eight dogs had ONFH, with non-union in five and malunion in three on radiological examination. Histologically, the untreated femoral heads developed osteonecrosis with an accumulation of bone marrow cell debris, empty lacunae and/or ghost nuclei in the lacunae, and an increase in the number of fat cells. Immunohistochemical staining of caspase-3 indicated that it was upregulated in fracture-induced ONFH two weeks postoperatively, which showed a statistical difference when compared to the normal side. In conclusion, the local expression of caspase-3 was upregulated in fracture-induced ONFH, suggesting that cell apoptosis is crucial in traumatic ONFH. Caspase-3 may therefore be employed as an effective and early predictor for fracture-induced ONFH.

  5. Automatic segmentation of head and neck CT images for radiotherapy treatment planning using multiple atlases, statistical appearance models, and geodesic active contours

    Science.gov (United States)

    Fritscher, Karl D.; Peroni, Marta; Zaffino, Paolo; Spadea, Maria Francesca; Schubert, Rainer; Sharp, Gregory

    2014-01-01

    Purpose: Accurate delineation of organs at risk (OARs) is a precondition for intensity modulated radiation therapy. However, manual delineation of OARs is time consuming and prone to high interobserver variability. Because of image artifacts and low image contrast between different structures, however, the number of available approaches for autosegmentation of structures in the head-neck area is still rather low. In this project, a new approach for automated segmentation of head-neck CT images that combine the robustness of multiatlas-based segmentation with the flexibility of geodesic active contours and the prior knowledge provided by statistical appearance models is presented. Methods: The presented approach is using an atlas-based segmentation approach in combination with label fusion in order to initialize a segmentation pipeline that is based on using statistical appearance models and geodesic active contours. An anatomically correct approximation of the segmentation result provided by atlas-based segmentation acts as a starting point for an iterative refinement of this approximation. The final segmentation result is based on using model to image registration and geodesic active contours, which are mutually influencing each other. Results: 18 CT images in combination with manually segmented labels of parotid glands and brainstem were used in a leave-one-out cross validation scheme in order to evaluate the presented approach. For this purpose, 50 different statistical appearance models have been created and used for segmentation. Dice coefficient (DC), mean absolute distance and max. Hausdorff distance between the autosegmentation results and expert segmentations were calculated. An average Dice coefficient of DC = 0.81 (right parotid gland), DC = 0.84 (left parotid gland), and DC = 0.86 (brainstem) could be achieved. Conclusions: The presented framework provides accurate segmentation results for three important structures in the head neck area. Compared to a

  6. Automatic segmentation of head and neck CT images for radiotherapy treatment planning using multiple atlases, statistical appearance models, and geodesic active contours

    International Nuclear Information System (INIS)

    Fritscher, Karl D.; Sharp, Gregory; Peroni, Marta; Zaffino, Paolo; Spadea, Maria Francesca; Schubert, Rainer

    2014-01-01

    Purpose: Accurate delineation of organs at risk (OARs) is a precondition for intensity modulated radiation therapy. However, manual delineation of OARs is time consuming and prone to high interobserver variability. Because of image artifacts and low image contrast between different structures, however, the number of available approaches for autosegmentation of structures in the head-neck area is still rather low. In this project, a new approach for automated segmentation of head-neck CT images that combine the robustness of multiatlas-based segmentation with the flexibility of geodesic active contours and the prior knowledge provided by statistical appearance models is presented. Methods: The presented approach is using an atlas-based segmentation approach in combination with label fusion in order to initialize a segmentation pipeline that is based on using statistical appearance models and geodesic active contours. An anatomically correct approximation of the segmentation result provided by atlas-based segmentation acts as a starting point for an iterative refinement of this approximation. The final segmentation result is based on using model to image registration and geodesic active contours, which are mutually influencing each other. Results: 18 CT images in combination with manually segmented labels of parotid glands and brainstem were used in a leave-one-out cross validation scheme in order to evaluate the presented approach. For this purpose, 50 different statistical appearance models have been created and used for segmentation. Dice coefficient (DC), mean absolute distance and max. Hausdorff distance between the autosegmentation results and expert segmentations were calculated. An average Dice coefficient of DC = 0.81 (right parotid gland), DC = 0.84 (left parotid gland), and DC = 0.86 (brainstem) could be achieved. Conclusions: The presented framework provides accurate segmentation results for three important structures in the head neck area. Compared to a

  7. Head circumference (image)

    Science.gov (United States)

    Head circumference is a measurement of the circumference of the child's head at its largest area, above the eyebrows and ears and around the back of the head. During routine check-ups, the distance is measured ...

  8. Abnormal Head Position

    Science.gov (United States)

    ... Frequently Asked Questions Español Condiciones Chinese Conditions Abnormal Head Position En Español Read in Chinese What is an abnormal head posture? An abnormal or compensatory head posture occurs ...

  9. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... of the Head? What is CT Scanning of the Head? Computed tomography, more commonly known as a ... of page What are some common uses of the procedure? CT scanning of the head is typically ...

  10. Head Impact Laboratory (HIL)

    Data.gov (United States)

    Federal Laboratory Consortium — The HIL uses testing devices to evaluate vehicle interior energy attenuating (EA) technologies for mitigating head injuries resulting from head impacts during mine/...

  11. A Preliminary Investigation of Traumatically Induced Axonal Injury in a Three-Dimensional (3-D) Finite Element Model (FEM) of the Human Head During Blast-Loading

    Science.gov (United States)

    2013-07-01

    properties. Material Model Material Properties Scalp/skin/fat/muscle Elastic  = 1050 kg/m 3 E = 1.67e7 Pa  = 0.42 Skull and vertebral bones Elastic...The skull rotation angle was calculated from the axis created from the foramen magnum to the top of the cranial bone. The skull was assumed to be...ms after the initial contact of the blast wave. The time evolution of axonal strain indicated that axonal injuries increased as a consequence of head

  12. Biomechanical evaluation of the long head of the biceps brachii tendon fixed by three techniques: a sheep model

    Directory of Open Access Journals (Sweden)

    Carlos Henrique Ramos

    Full Text Available ABSTRACT OBJECTIVE: To evaluate the biomechanical properties of the fixation of the long head of the biceps brachii into the humeral bone with suture anchors, interference screw, and soft tissue suture, comparing strength, highest traction load, and types of fixation failure. METHODS: Thirty fresh-frozen sheep shoulders were used, separated into three groups of ten for each technique. After fixation, the tendons were subjected to longitudinal continuous loading, obtaining load-to-failure (N and displacement (mm. RESULTS: The mean load-to-failure for suture anchors was 95 ± 35.3 N, 152.7 ± 52.7 N for interference screw, and 104.7 ± 23.54 N for soft tissue technique. There was a statistically significant difference (p < 0.05, with interference screw demonstrating higher load-to-failure than suture anchor fixation (p = 0.00307 and soft tissue (p = 0.00473. The strength of interference screw was also superior when compared with the other two methods (p = 0.0000127 and p = 0.00000295, respectively. There were no differences between suture anchors and soft tissue technique regarding load-to-failure (p = 0.9420 and strength (p = 0.141. CONCLUSION: Tenodesis of the long head of the biceps brachii with interference screw was stronger than the suture anchors and soft tissue techniques. The other two techniques did not differ between themselves.

  13. Quality of Life of Women Heading Family: the Role of Resiliency, and Family Functioning Based on Mc Master Model

    Directory of Open Access Journals (Sweden)

    زهرا سادات رضایی

    2017-12-01

    Full Text Available Single mothers who head the families face many problems; and multiple roles for women cause negative effects on their health, satisfaction and quality of life in these women. In this study, quality of life and family functioning and the mediating role of resiliency in these families were investigated. All households headed by woman in Tehran were our statistical population. Due to the type of research, the inventory and its subscales, the sample size was determined as 160 individuals who were selected through the available sampling method. Family Assessment Scale, Quality of Life Inventory and Connor-Davidson Resilience Scale were given as a battery of scales. Results showed that there is a significant positive relationship between resiliency with physical health, mental health, environmental health and social relations. There was a significant negative correlation between aspects of quality of life and resiliency with all subscales of the Family Function Device scales. Also mediating role of resiliency in the suggested relationships between general family functioning and physical health, roles with mental health, roles and general functioning with environmental health, and between general functioning and the roles with social relationship were significant. It can be resiliency might be recognized as an effective variable in the relationship between quality of life and family function levels.

  14. THE USE OF NUMBERED HEADS TOGETHER (NHT LEARNING MODEL WITH SCIENCE, ENVIRONMENT, TECHNOLOGY, SOCIETY (SETS APPROACH TO IMPROVE STUDENT LEARNING MOTIVATION OF SENIOR HIGH SCHOOL

    Directory of Open Access Journals (Sweden)

    B. Sutipnyo

    2018-01-01

    Full Text Available This research was aimed to determine the increasing of students' motivation that has been applied by Numbered Heads Together (NHT learning model with Science, Environment, Technology, Society (SETS approach. The design of this study was quasi experiment with One Group Pretest-Posttest Design. The data of students’ learning motivation obtained through questionnaire administered before and after NHT learning model with SETS approach. In this research, the indicators of learning-motivation were facing tasks diligently, showing interest in variety of problems, prefering to work independently, keeping students’ opinions, and feeling happy to find and solve problems. Increasing of the students’ learning motivation was analyzed by using a gain test. The results showed that applying NHT learning model with SETS approach could increase the students’ learning motivation in medium categories.

  15. Atlas-based head modeling and spatial normalization for high-density diffuse optical tomography: in vivo validation against fMRI.

    Science.gov (United States)

    Ferradal, Silvina L; Eggebrecht, Adam T; Hassanpour, Mahlega; Snyder, Abraham Z; Culver, Joseph P

    2014-01-15

    Diffuse optical imaging (DOI) is increasingly becoming a valuable neuroimaging tool when fMRI is precluded. Recent developments in high-density diffuse optical tomography (HD-DOT) overcome previous limitations of sparse DOI systems, providing improved image quality and brain specificity. These improvements in instrumentation prompt the need for advancements in both i) realistic forward light modeling for accurate HD-DOT image reconstruction, and ii) spatial normalization for voxel-wise comparisons across subjects. Individualized forward light models derived from subject-specific anatomical images provide the optimal inverse solutions, but such modeling may not be feasible in all situations. In the absence of subject-specific anatomical images, atlas-based head models registered to the subject's head using cranial fiducials provide an alternative solution. In addition, a standard atlas is attractive because it defines a common coordinate space in which to compare results across subjects. The question therefore arises as to whether atlas-based forward light modeling ensures adequate HD-DOT image quality at the individual and group level. Herein, we demonstrate the feasibility of using atlas-based forward light modeling and spatial normalization methods. Both techniques are validated using subject-matched HD-DOT and fMRI data sets for visual evoked responses measured in five healthy adult subjects. HD-DOT reconstructions obtained with the registered atlas anatomy (i.e. atlas DOT) had an average localization error of 2.7mm relative to reconstructions obtained with the subject-specific anatomical images (i.e. subject-MRI DOT), and 6.6mm relative to fMRI data. At the group level, the localization error of atlas DOT reconstruction was 4.2mm relative to subject-MRI DOT reconstruction, and 6.1mm relative to fMRI. These results show that atlas-based image reconstruction provides a viable approach to individual head modeling for HD-DOT when anatomical imaging is not available

  16. A comparison of dose-response models for the parotid gland in a large group of head-and-neck cancer patients.

    Science.gov (United States)

    Houweling, Antonetta C; Philippens, Marielle E P; Dijkema, Tim; Roesink, Judith M; Terhaard, Chris H J; Schilstra, Cornelis; Ten Haken, Randall K; Eisbruch, Avraham; Raaijmakers, Cornelis P J

    2010-03-15

    The dose-response relationship of the parotid gland has been described most frequently using the Lyman-Kutcher-Burman model. However, various other normal tissue complication probability (NTCP) models exist. We evaluated in a large group of patients the value of six NTCP models that describe the parotid gland dose response 1 year after radiotherapy. A total of 347 patients with head-and-neck tumors were included in this prospective parotid gland dose-response study. The patients were treated with either conventional radiotherapy or intensity-modulated radiotherapy. Dose-volume histograms for the parotid glands were derived from three-dimensional dose calculations using computed tomography scans. Stimulated salivary flow rates were measured before and 1 year after radiotherapy. A threshold of 25% of the pretreatment flow rate was used to define a complication. The evaluated models included the Lyman-Kutcher-Burman model, the mean dose model, the relative seriality model, the critical volume model, the parallel functional subunit model, and the dose-threshold model. The goodness of fit (GOF) was determined by the deviance and a Monte Carlo hypothesis test. Ranking of the models was based on Akaike's information criterion (AIC). None of the models was rejected based on the evaluation of the GOF. The mean dose model was ranked as the best model based on the AIC. The TD(50) in these models was approximately 39 Gy. The mean dose model was preferred for describing the dose-response relationship of the parotid gland. Copyright 2010 Elsevier Inc. All rights reserved.

  17. Normal tissue complication probability (NTCP) modelling using spatial dose metrics and machine learning methods for severe acute oral mucositis resulting from head and neck radiotherapy.

    Science.gov (United States)

    Dean, Jamie A; Wong, Kee H; Welsh, Liam C; Jones, Ann-Britt; Schick, Ulrike; Newbold, Kate L; Bhide, Shreerang A; Harrington, Kevin J; Nutting, Christopher M; Gulliford, Sarah L

    2016-07-01

    Severe acute mucositis commonly results from head and neck (chemo)radiotherapy. A predictive model of mucositis could guide clinical decision-making and inform treatment planning. We aimed to generate such a model using spatial dose metrics and machine learning. Predictive models of severe acute mucositis were generated using radiotherapy dose (dose-volume and spatial dose metrics) and clinical data. Penalised logistic regression, support vector classification and random forest classification (RFC) models were generated and compared. Internal validation was performed (with 100-iteration cross-validation), using multiple metrics, including area under the receiver operating characteristic curve (AUC) and calibration slope, to assess performance. Associations between covariates and severe mucositis were explored using the models. The dose-volume-based models (standard) performed equally to those incorporating spatial information. Discrimination was similar between models, but the RFCstandard had the best calibration. The mean AUC and calibration slope for this model were 0.71 (s.d.=0.09) and 3.9 (s.d.=2.2), respectively. The volumes of oral cavity receiving intermediate and high doses were associated with severe mucositis. The RFCstandard model performance is modest-to-good, but should be improved, and requires external validation. Reducing the volumes of oral cavity receiving intermediate and high doses may reduce mucositis incidence. Copyright © 2016 The Author(s). Published by Elsevier Ireland Ltd.. All rights reserved.

  18. Head-wave coefficients in anisotropic media

    Science.gov (United States)

    Chapman, Chris

    2018-03-01

    Reflections and transmissions from interfaces can generate head waves. Although the kinematic properties of head waves are modelled simply using ray concepts, the dynamic properties require an extension of ray theory or the use of wave theory. Head waves are important in exploration and crustal seismology as they indicate the existence of an interface and the velocity of the generating wave. Head waves have been described in the literature for isotropic media but the extension to anisotropic media seems to be lacking. The expressions for the head-wave coefficients using ray concepts or wave theory differ, and their equality is not obvious. This paper extends the theory for head-wave coefficients to anisotropic media using both ray theory and wave theory, and generalizes the proof of equality of the two methods. Simple numerical examples confirm this equality and indicate how the head-wave results can be calculated in anisotropic media and included in a ray-tracing algorithm.

  19. SU-E-T-360: End-To-End Dosimetric Testing of a Versa HD Linear Accelerator with the Agility Head Modeled in Pinnacle3

    Energy Technology Data Exchange (ETDEWEB)

    Saenz, D; Narayanasamy, G; Cruz, W; Papanikolaou, N; Stathakis, S [University of Texas Health Science Center at San Antonio, San Antonio, TX (United States)

    2015-06-15

    Purpose: The Versa HD incorporates a variety of upgrades, primarily including the Agility head. The distinct dosimetric properties of the head from its predecessors combined with flattening-filter-free (FFF) beams require a new investigation of modeling in planning systems and verification of modeling accuracy. Methods: A model was created in Pinnacle{sup 3} v9.8 with commissioned beam data. Leaf transmission was modeled as <0.5% with maximum leaf speed of 3 cm/s. Photon spectra were tuned for FFF beams, for which profiles were modeled with arbitrary profiles rather than with cones. For verification, a variety of plans with varied parameters were devised, and point dose measurements were compared to calculated values. A phantom of several plastic water and Styrofoam slabs was scanned and imported into Pinnacle{sup 3}. Beams of different field sizes, SSD, wedges, and gantry angles were created. All available photon energies (6 MV, 10 MV, 18 MV, 6 FFF, 10 FFF) as well four clinical electron energies (6, 9, 12, and 15 MeV) were investigated. The plans were verified at a calculation point (8 cm deep for photons, variable for electrons) by measurement with a PTW Semiflex ionization chamber. In addition, IMRT testing was performed with three standard plans (step and shoot IMRT, small and large field VMAT plans). The plans were delivered on the Delta4 IMRT QA phantom (ScandiDos, Uppsala, Sweden). Results: Homogeneous point dose measurement agreed within 2% for all photon and electron beams. Open field photon measurements along the central axis at 100 cm SSD passed within 1%. Gamma passing rates were >99.5% for all plans with a 3%/3mm tolerance criteria. The IMRT QA results for the first 23 patients yielded gamma passing rates of 97.4±2.3%. Conclusion: The end-to-end testing ensured confidence in the ability of Pinnacle{sup 3} to model photon and electron beams with the Agility head.

  20. Head and neck cancer

    International Nuclear Information System (INIS)

    Vogl, S.E.

    1988-01-01

    This book contains 10 chapters. Some of the titles are: Combined Surgical Resection and Irradiation for Head and Neck Cancers; Analysis of Radiation Therapy Oncology Group Head and Neck Database: Identification of Prognostic Factors and the Re-evaluation of American Joint Committee Stages; Combined Modality Approach to Head and Neck Cancer; Induction Combination Chemotherapy of Regionally Advanced Head and Neck Cancer; and Outcome after Complete Remission to Induction Chemotherapy in Head and Neck Cancer

  1. Biomechanical evaluation of the long head of the biceps brachii tendon fixed by three techniques: a sheep model.

    Science.gov (United States)

    Ramos, Carlos Henrique; Coelho, Júlio Cezar Uili

    2017-01-01

    To evaluate the biomechanical properties of the fixation of the long head of the biceps brachii into the humeral bone with suture anchors, interference screw, and soft tissue suture, comparing strength, highest traction load, and types of fixation failure. Thirty fresh-frozen sheep shoulders were used, separated into three groups of ten for each technique. After fixation, the tendons were subjected to longitudinal continuous loading, obtaining load-to-failure (N) and displacement (mm). The mean load-to-failure for suture anchors was 95 ± 35.3 N, 152.7 ± 52.7 N for interference screw, and 104.7 ± 23.54 N for soft tissue technique. There was a statistically significant difference ( p  < 0.05), with interference screw demonstrating higher load-to-failure than suture anchor fixation ( p  = 0.00307) and soft tissue ( p  = 0.00473). The strength of interference screw was also superior when compared with the other two methods ( p  = 0.0000127 and p  = 0.00000295, respectively). There were no differences between suture anchors and soft tissue technique regarding load-to-failure ( p  = 0.9420) and strength ( p  = 0.141). Tenodesis of the long head of the biceps brachii with interference screw was stronger than the suture anchors and soft tissue techniques. The other two techniques did not differ between themselves.

  2. Contributory fault and level of personal injury to drivers involved in head-on collisions: Application of copula-based bivariate ordinal models.

    Science.gov (United States)

    Wali, Behram; Khattak, Asad J; Xu, Jingjing

    2018-01-01

    The main objective of this study is to simultaneously investigate the degree of injury severity sustained by drivers involved in head-on collisions with respect to fault status designation. This is complicated to answer due to many issues, one of which is the potential presence of correlation between injury outcomes of drivers involved in the same head-on collision. To address this concern, we present seemingly unrelated bivariate ordered response models by analyzing the joint injury severity probability distribution of at-fault and not-at-fault drivers. Moreover, the assumption of bivariate normality of residuals and the linear form of stochastic dependence implied by such models may be unduly restrictive. To test this, Archimedean copula structures and normal mixture marginals are integrated into the joint estimation framework, which can characterize complex forms of stochastic dependencies and non-normality in residual terms. The models are estimated using 2013 Virginia police reported two-vehicle head-on collision data, where exactly one driver is at-fault. The results suggest that both at-fault and not-at-fault drivers sustained serious/fatal injuries in 8% of crashes, whereas, in 4% of the cases, the not-at-fault driver sustained a serious/fatal injury with no injury to the at-fault driver at all. Furthermore, if the at-fault driver is fatigued, apparently asleep, or has been drinking the not-at-fault driver is more likely to sustain a severe/fatal injury, controlling for other factors and potential correlations between the injury outcomes. While not-at-fault vehicle speed affects injury severity of at-fault driver, the effect is smaller than the effect of at-fault vehicle speed on at-fault injury outcome. Contrarily, and importantly, the effect of at-fault vehicle speed on injury severity of not-at-fault driver is almost equal to the effect of not-at-fault vehicle speed on injury outcome of not-at-fault driver. Compared to traditional ordered probability

  3. Monitoring hemodynamic and morphologic responses to closed head injury in a mouse model using orthogonal diffuse near-infrared light reflectance spectroscopy

    Science.gov (United States)

    Abookasis, David; Shochat, Ariel; Mathews, Marlon S.

    2013-04-01

    The authors' aim is to assess and quantitatively measure brain hemodynamic and morphological variations during closed-head injury (CHI) in mice using orthogonal diffuse near-infrared reflectance spectroscopy (o-DRS). CHI is a type of injury to the head that does not penetrate the skull. Usually, it is caused by mechanical blows to the head and frequently occurs in traffic accidents, falls, and assaults. Measurements of brain optical properties, namely absorption and reduced scattering coefficients in the wavelength range from 650 to 1000 nm were carried out by employing different source-detector distance and locations to provide depth sensitivity on an intact scalp over the duration of the whole experiment. Furthermore, alteration in both cortical hemodynamics and morphologic markers, i.e., scattering power and amplitude properties were derived. CHI was induced in anesthetized male mice by a weight-drop model using ˜50 g cylindrical metal falling from a height of 90 cm onto the intact scalp producing an impact of 4500 g cm. With respect to baseline, difference in brain physiological properties was observed following injury up to 1 h post-trauma. Additionally, the reduced scattering spectral shapes followed Mie scattering theory was quantified and clearly shows changes in both scattering amplitude and power from baseline indicating structural variations likely from evolving cerebral edema during CHI. We further demonstrate high correlation between scattering amplitude and scattering power, with more than 20% difference in slope in comparison to preinjury. This result indicates the possibility of using the slope also as a marker for detection of structural changes. Finally, experiments investigating brain function during the first 20 min postinjury were conducted and changes in chromophore concentrations and scattering were observed. Overall, our experiments demonstrate the potential of using the proposed technique as a valuable quantitative noninvasive tool for

  4. Residual tumour detection in post-treatment granulation tissue by using advanced diffusion models in head and neck squamous cell carcinoma patients.

    Science.gov (United States)

    Fujima, Noriyuki; Yoshida, Daisuke; Sakashita, Tomohiro; Homma, Akihiro; Kudo, Kohsuke; Shirato, Hiroki

    2017-05-01

    To evaluate the detectability of the residual tumour in post-treatment granulation tissue using parameters obtained with an advanced diffusion model in patients with head and neck squamous cell carcinoma (HNSCC) treated by chemoradiation therapy. We retrospectively evaluated 23 patients with HNSCC after the full course of chemoradiation therapy. The diffusion-weighted image (DWI) acquisition used single-shot spin-echo echo-planar imaging with 11 b-values (0-1000). We calculated 10 DWI parameters using a mono-exponential model, a bi-exponential model, a stretched exponential model (SEM), a diffusion kurtosis imaging (DKI) model and a statistical diffusion model (SDM) in the region of interest (ROI) placed on the post-treatment granulation tissue. The presence of residual tumour was determined by histological findings or clinical follow-up. Among the 23 patients, seven patients were revealed to have residual tumour. The univariate analysis revealed significant differences in six parameters between the patients with and without residual tumour. From the receiver operating characteristic curve analysis, the highest area under curve was detected in the center of the Gaussian distribution of diffusion coefficient (D s ) obtained by the SDM. The multivariate analysis revealed that the D s and diffusion heterogeneity (α) obtained by the SEM were predictors for the presence of residual tumour. DWI parameters obtained by advanced fitting models will be one of the diagnostic tools for the detection of residual tumour. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Incorporating spatial dose metrics in machine learning-based normal tissue complication probability (NTCP) models of severe acute dysphagia resulting from head and neck radiotherapy.

    Science.gov (United States)

    Dean, Jamie; Wong, Kee; Gay, Hiram; Welsh, Liam; Jones, Ann-Britt; Schick, Ulricke; Oh, Jung Hun; Apte, Aditya; Newbold, Kate; Bhide, Shreerang; Harrington, Kevin; Deasy, Joseph; Nutting, Christopher; Gulliford, Sarah

    2018-01-01

    Severe acute dysphagia commonly results from head and neck radiotherapy (RT). A model enabling prediction of severity of acute dysphagia for individual patients could guide clinical decision-making. Statistical associations between RT dose distributions and dysphagia could inform RT planning protocols aiming to reduce the incidence of severe dysphagia. We aimed to establish such a model and associations incorporating spatial dose metrics. Models of severe acute dysphagia were developed using pharyngeal mucosa (PM) RT dose (dose-volume and spatial dose metrics) and clinical data. Penalized logistic regression (PLR), support vector classification and random forest classification (RFC) models were generated and internally (173 patients) and externally (90 patients) validated. These were compared using area under the receiver operating characteristic curve (AUC) to assess performance. Associations between treatment features and dysphagia were explored using RFC models. The PLR model using dose-volume metrics (PLR standard ) performed as well as the more complex models and had very good discrimination (AUC = 0.82) on external validation. The features with the highest RFC importance values were the volume, length and circumference of PM receiving 1 Gy/fraction and higher. The volumes of PM receiving 1 Gy/fraction or higher should be minimized to reduce the incidence of severe acute dysphagia.

  6. Incorporating spatial dose metrics in machine learning-based normal tissue complication probability (NTCP models of severe acute dysphagia resulting from head and neck radiotherapy

    Directory of Open Access Journals (Sweden)

    Jamie Dean

    2018-01-01

    Full Text Available Severe acute dysphagia commonly results from head and neck radiotherapy (RT. A model enabling prediction of severity of acute dysphagia for individual patients could guide clinical decision-making. Statistical associations between RT dose distributions and dysphagia could inform RT planning protocols aiming to reduce the incidence of severe dysphagia. We aimed to establish such a model and associations incorporating spatial dose metrics. Models of severe acute dysphagia were developed using pharyngeal mucosa (PM RT dose (dose-volume and spatial dose metrics and clinical data. Penalized logistic regression (PLR, support vector classification and random forest classification (RFC models were generated and internally (173 patients and externally (90 patients validated. These were compared using area under the receiver operating characteristic curve (AUC to assess performance. Associations between treatment features and dysphagia were explored using RFC models. The PLR model using dose-volume metrics (PLRstandard performed as well as the more complex models and had very good discrimination (AUC = 0.82 on external validation. The features with the highest RFC importance values were the volume, length and circumference of PM receiving 1 Gy/fraction and higher. The volumes of PM receiving 1 Gy/fraction or higher should be minimized to reduce the incidence of severe acute dysphagia.

  7. 3D Rapid Prototyping for Otolaryngology—Head and Neck Surgery: Applications in Image-Guidance, Surgical Simulation and Patient-Specific Modeling

    Science.gov (United States)

    Chan, Harley H. L.; Siewerdsen, Jeffrey H.; Vescan, Allan; Daly, Michael J.; Prisman, Eitan; Irish, Jonathan C.

    2015-01-01

    The aim of this study was to demonstrate the role of advanced fabrication technology across a broad spectrum of head and neck surgical procedures, including applications in endoscopic sinus surgery, skull base surgery, and maxillofacial reconstruction. The initial case studies demonstrated three applications of rapid prototyping technology are in head and neck surgery: i) a mono-material paranasal sinus phantom for endoscopy training ii) a multi-material skull base simulator and iii) 3D patient-specific mandible templates. Digital processing of these phantoms is based on real patient or cadaveric 3D images such as CT or MRI data. Three endoscopic sinus surgeons examined the realism of the endoscopist training phantom. One experienced endoscopic skull base surgeon conducted advanced sinus procedures on the high-fidelity multi-material skull base simulator. Ten patients participated in a prospective clinical study examining patient-specific modeling for mandibular reconstructive surgery. Qualitative feedback to assess the realism of the endoscopy training phantom and high-fidelity multi-material phantom was acquired. Conformance comparisons using assessments from the blinded reconstructive surgeons measured the geometric performance between intra-operative and pre-operative reconstruction mandible plates. Both the endoscopy training phantom and the high-fidelity multi-material phantom received positive feedback on the realistic structure of the phantom models. Results suggested further improvement on the soft tissue structure of the phantom models is necessary. In the patient-specific mandible template study, the pre-operative plates were judged by two blinded surgeons as providing optimal conformance in 7 out of 10 cases. No statistical differences were found in plate fabrication time and conformance, with pre-operative plating providing the advantage of reducing time spent in the operation room. The applicability of common model design and fabrication techniques

  8. 3D Rapid Prototyping for Otolaryngology-Head and Neck Surgery: Applications in Image-Guidance, Surgical Simulation and Patient-Specific Modeling.

    Directory of Open Access Journals (Sweden)

    Harley H L Chan

    Full Text Available The aim of this study was to demonstrate the role of advanced fabrication technology across a broad spectrum of head and neck surgical procedures, including applications in endoscopic sinus surgery, skull base surgery, and maxillofacial reconstruction. The initial case studies demonstrated three applications of rapid prototyping technology are in head and neck surgery: i a mono-material paranasal sinus phantom for endoscopy training ii a multi-material skull base simulator and iii 3D patient-specific mandible templates. Digital processing of these phantoms is based on real patient or cadaveric 3D images such as CT or MRI data. Three endoscopic sinus surgeons examined the realism of the endoscopist training phantom. One experienced endoscopic skull base surgeon conducted advanced sinus procedures on the high-fidelity multi-material skull base simulator. Ten patients participated in a prospective clinical study examining patient-specific modeling for mandibular reconstructive surgery. Qualitative feedback to assess the realism of the endoscopy training phantom and high-fidelity multi-material phantom was acquired. Conformance comparisons using assessments from the blinded reconstructive surgeons measured the geometric performance between intra-operative and pre-operative reconstruction mandible plates. Both the endoscopy training phantom and the high-fidelity multi-material phantom received positive feedback on the realistic structure of the phantom models. Results suggested further improvement on the soft tissue structure of the phantom models is necessary. In the patient-specific mandible template study, the pre-operative plates were judged by two blinded surgeons as providing optimal conformance in 7 out of 10 cases. No statistical differences were found in plate fabrication time and conformance, with pre-operative plating providing the advantage of reducing time spent in the operation room. The applicability of common model design and

  9. Normal tissue complication probability modeling for cochlea constraints to avoid causing tinnitus after head-and-neck intensity-modulated radiation therapy

    International Nuclear Information System (INIS)

    Lee, Tsair-Fwu; Yeh, Shyh-An; Chao, Pei-Ju; Chang, Liyun; Chiu, Chien-Liang; Ting, Hui-Min; Wang, Hung-Yu; Huang, Yu-Jie

    2015-01-01

    Radiation-induced tinnitus is a side effect of radiotherapy in the inner ear for cancers of the head and neck. Effective dose constraints for protecting the cochlea are under-reported. The aim of this study is to determine the cochlea dose limitation to avoid causing tinnitus after head-and-neck cancer (HNC) intensity-modulated radiation therapy (IMRT). In total 211 patients with HNC were included; the side effects of radiotherapy were investigated for 422 inner ears in the cohort. Forty-nine of the four hundred and twenty-two samples (11.6 %) developed grade 2+ tinnitus symptoms after IMRT, as diagnosed by a clinician. The Late Effects of Normal Tissues–Subjective, Objective, Management, Analytic (LENT-SOMA) criteria were used for tinnitus evaluation. The logistic and Lyman-Kutcher-Burman (LKB) normal tissue complication probability (NTCP) models were used for the analyses. The NTCP-fitted parameters were TD 50 = 46.31 Gy (95 % CI, 41.46–52.50), γ 50 = 1.27 (95 % CI, 1.02–1.55), and TD 50 = 46.52 Gy (95 % CI, 41.91–53.43), m = 0.35 (95 % CI, 0.30–0.42) for the logistic and LKB models, respectively. The suggested guideline TD 20 for the tolerance dose to produce a 20 % complication rate within a specific period of time was TD 20 = 33.62 Gy (95 % CI, 30.15–38.27) (logistic) and TD 20 = 32.82 Gy (95 % CI, 29.58–37.69) (LKB). To maintain the incidence of grade 2+ tinnitus toxicity <20 % in IMRT, we suggest that the mean dose to the cochlea should be <32 Gy. However, models should not be extrapolated to other patient populations without further verification and should first be confirmed before clinical implementation

  10. Thermal Index Evaluation of Local SAR in MRI-Based Head Models of Adult and Children for Portable Telephones

    Science.gov (United States)

    Fujiwara, Osamu; Miyamoto, Kayoko; Wang, Jianqing

    Biological hazards due to radio-frequency (RF) waves result mainly from the temperature rise in tissue. It should be, therefore, clarified to what extent the RF waves of portable telephones increase the temperature-rise in human brain that includes the central part governing the body-temperature regulation function. In this paper, we calculated both the specific absorption rate (SAR) and the resultant temperature-rise for 900 MHz and 2 GHz portable telephones using the finite-difference time-domain (FDTD) method for three typical use positions, i.e., the vertical position, cheek position and tilt position. As a result, we found that there was an increase for median and 1% value of the cumulative distribution of temperature-rise in children’s brains for any use positions of the portable telephones compared to that in the adult’s brain, and also that the increasing trend in children’s brains for temperature-rise is identical to the temperature-rise trend in children’s hypothalamus. In addition, we found that the ten-gram averaged peak SAR among the adult and children heads had the same trend as that of the 0.1% value of the relatively cumulative distribution of temperature-rise, which shows that the ten-gram averaged peak SAR reflects only the localized temperature-rise in the brain surface.

  11. Reconstruction of head-to-knee voxel model for Syrian adult male of average height and weight

    Directory of Open Access Journals (Sweden)

    Bashira Taleb

    2015-06-01

    Conclusion: Comparisons with SAFs data of Zubal model accentuated the fact that the organ masses and the specific anatomy have a significant effect on SAFs. SyrMan model can be considered as the first model built in the Middle East region, and it is an important step toward the Syrian Reference Man.

  12. Head and face reconstruction

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/002980.htm Head and face reconstruction To use the sharing features on this page, please enable JavaScript. Head and face reconstruction is surgery to repair or ...

  13. Head CT scan

    Science.gov (United States)

    ... CT; Cranial CT; CT scan - skull; CT scan - head; CT scan - orbits; CT scan - sinuses; Computed tomography - ... Head CT is done in the hospital or radiology center. You lie on a narrow table that ...

  14. Head Lice: Diagnosis

    Science.gov (United States)

    ... CDC Cancel Submit Search The CDC Parasites - Lice - Head Lice Note: Javascript is disabled or is not ... please visit this page: About CDC.gov . Lice Head Lice General Information Frequently Asked Questions (FAQs) Treatment ...

  15. Head and Neck Cancer

    Science.gov (United States)

    Head and neck cancer includes cancers of the mouth, nose, sinuses, salivary glands, throat, and lymph nodes ... swallowing A change or hoarseness in the voice Head and neck cancers are twice as common in ...

  16. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... the limitations of CT Scanning of the Head? What is CT Scanning of the Head? Computed tomography, ... than regular radiographs (x-rays). top of page What are some common uses of the procedure? CT ...

  17. Head injury - first aid

    Science.gov (United States)

    ... medlineplus.gov/ency/article/000028.htm Head injury - first aid To use the sharing features on this page, ... a concussion can range from mild to severe. First Aid Learning to recognize a serious head injury and ...

  18. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... for Brain Tumors Radiation Therapy for Head and Neck Cancer Others American Stroke Association National Stroke Association ... Computer Tomography (CT) Safety During Pregnancy Head and Neck Cancer X-ray, Interventional Radiology and Nuclear Medicine ...

  19. Comparison of pre- and postimplantation development following the application of three artificial activating stimuli in a mouse model with round-headed sperm cells deficient for oocyte activation

    DEFF Research Database (Denmark)

    Vanden Meerschaut, Frauke; Nikiforaki, D.; De Roo, C.

    2013-01-01

    was significantly lower at weeks 2, 3 and 4 when compared with female pups originating from WT embryos. However, the latter difference was not observed at later time points, nor in the other artificial activating groups. All offspring mated successfully with fertile controls. LIMITATIONS, REASONS FOR CAUTION......STUDY QUESTION Does the application of three different artificial activating stimuli lead to a difference in pre- and post-implantation embryo development in the wobbler mouse, a mouse model with oocyte activation deficient round-headed sperm cells similar to human globozoospermia? SUMMARY ANSWER...... No gross differences were found between strontium chloride, electrical pulses or ionomycin with respect to the pre- and post-implantation development in the wobbler mouse. WHAT IS KNOWN ALREADY Fertilization failure following intra-cytoplasmic sperm injection (ICSI) occurs in 1–3% of the ICSI cycles...

  20. Eksperimentasi Model Pembelajaran Numbered Head Together dan Think-talk-write dengan Pendekatan Saintifik pada Materi Sistem Persamaan dan Pertidaksamaan Ditinjau dari Sikap Percaya Diri Siswa Kelas X Peminatan IPA SMA Negeri di Kota Surakarta

    OpenAIRE

    Putri, Diah Purwaning; Budiyono, Budiyono; Sari Saputro, Dewi Retno

    2016-01-01

    The purpose of this study was to determine the effect of the learning models on the learning achievement in Mathematics seen from the self confidence attitude of the students. The learning models compared were the cooperative learning model of the Numbered Head Together (NHT) type using scientific approach, Think Talk Write (TTW) type using scientific approach, and classical model using scientific approach.This study was a quasi-experimental with a 3x3 factorial design. Instruments used for ...

  1. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... Perfusion of the Head CT Angiography (CTA) Stroke Brain Tumors Computer Tomography (CT) Safety During Pregnancy Head and Neck Cancer X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety Images related to Computed Tomography (CT) - Head Videos related to Computed Tomography ( ...

  2. Development of virtual anthropomorphism of head mathematical model for using in dosimetry computerized simulation; Desenvolvimento de modelo matematico antropomorfico virtual de cabeca para utilizacao em simulacao computacional de dosimetria

    Energy Technology Data Exchange (ETDEWEB)

    Cassola, V.F.; Hoff, G.; Streck, E.E. [Pontificia Univ. Catolica do Rio Grande do Sul, Porto Alegre, RS (Brazil). Faculdade de Fisica. Grupo de Experimentacao e Simulacao Computacional em Fisica (GESiC)]. E-mail: ghoff@pucrs.br

    2004-07-01

    This paper shows the development of a virtual anthropomorphous model of head, considering different tissue composition, based in Nuclear Magnetic Resonance (NMR) images. The head original images were acquired in an equipment of NMR GE Sigma Horizon LX 1.5 T Echo Speed, available in the clinic of diagnosis for image SIDI. These images were segmented using routines developed in C++ language. The generated model is a group of 124 matrices of sequential data in format ASCII, where 26 indices evidence different structures. (author)

  3. Systems analysis of the vestibulo-ocular system. [mathematical model of vestibularly driven head and eye movements

    Science.gov (United States)

    Schmid, R. M.

    1973-01-01

    The vestibulo-ocular system is examined from the standpoint of system theory. The evolution of a mathematical model of the vestibulo-ocular system in an attempt to match more and more experimental data is followed step by step. The final model explains many characteristics of the eye movement in vestibularly induced nystagmus. The analysis of the dynamic behavior of the model at the different stages of its development is illustrated in time domain, mainly in a qualitative way.

  4. Sediment transport in forested head water catchments - Calibration and validation of a soil erosion and landscape evolution model

    Science.gov (United States)

    Hancock, G. R.; Webb, A. A.; Turner, L.

    2017-11-01

    Sediment transport and soil erosion can be determined by a variety of field and modelling approaches. Computer based soil erosion and landscape evolution models (LEMs) offer the potential to be reliable assessment and prediction tools. An advantage of such models is that they provide both erosion and deposition patterns as well as total catchment sediment output. However, before use, like all models they require calibration and validation. In recent years LEMs have been used for a variety of both natural and disturbed landscape assessment. However, these models have not been evaluated for their reliability in steep forested catchments. Here, the SIBERIA LEM is calibrated and evaluated for its reliability for two steep forested catchments in south-eastern Australia. The model is independently calibrated using two methods. Firstly, hydrology and sediment transport parameters are inferred from catchment geomorphology and soil properties and secondly from catchment sediment transport and discharge data. The results demonstrate that both calibration methods provide similar parameters and reliable modelled sediment transport output. A sensitivity study of the input parameters demonstrates the model's sensitivity to correct parameterisation and also how the model could be used to assess potential timber harvesting as well as the removal of vegetation by fire.

  5. Investigation of head response to blast loading.

    Science.gov (United States)

    Lockhart, Philip; Cronin, Duane; Williams, Kevin; Ouellet, Simon

    2011-02-01

    Head injury resulting from blast loading, specifically mild traumatic brain injury, has been identified as a possible and important blast-related injury for soldiers in modern conflict zones. A study was undertaken to evaluate head response to blast loading scenarios using an explicit finite element numerical model and to comment on the potential for head injury. The blast loading and simplified human body numerical models were validated using impulse, peak acceleration and the Head Injury Criterion from experimental blast test data. A study was then undertaken to evaluate head response at varying distances and orientations from the explosive. The accelerations and injury metrics for the head increased with decreasing distance to the explosive, as expected, but were also significant at intermediate distances from the explosive for larger charge sizes and intermediate heights of burst. Varying lateral position with constant standoff did not have a significant effect on the head kinematic response. The head injury criteria considered were exceeded in close proximity to the explosive (blast loading, aggressive loading is predicted at small standoff distances and confirmed by the resulting head kinematics.

  6. Automatic skull segmentation from MR images for realistic volume conductor models of the head: Assessment of the state-of-the-art.

    Science.gov (United States)

    Nielsen, Jesper D; Madsen, Kristoffer H; Puonti, Oula; Siebner, Hartwig R; Bauer, Christian; Madsen, Camilla Gøbel; Saturnino, Guilherme B; Thielscher, Axel

    2018-03-12

    Anatomically realistic volume conductor models of the human head are important for accurate forward modeling of the electric field during transcranial brain stimulation (TBS), electro- (EEG) and magnetoencephalography (MEG). In particular, the skull compartment exerts a strong influence on the field distribution due to its low conductivity, suggesting the need to represent its geometry accurately. However, automatic skull reconstruction from structural magnetic resonance (MR) images is difficult, as compact bone has a very low signal in magnetic resonance imaging (MRI). Here, we evaluate three methods for skull segmentation, namely FSL BET2, the unified segmentation routine of SPM12 with extended spatial tissue priors, and the skullfinder tool of BrainSuite. To our knowledge, this study is the first to rigorously assess the accuracy of these state-of-the-art tools by comparison with CT-based skull segmentations on a group of ten subjects. We demonstrate several key factors that improve the segmentation quality, including the use of multi-contrast MRI data, the optimization of the MR sequences and the adaptation of the parameters of the segmentation methods. We conclude that FSL and SPM12 achieve better skull segmentations than BrainSuite. The former methods obtain reasonable results for the upper part of the skull when a combination of T1- and T2-weighted images is used as input. The SPM12-based results can be improved slightly further by means of simple morphological operations to fix local defects. In contrast to FSL BET2, the SPM12-based segmentation with extended spatial tissue priors and the BrainSuite-based segmentation provide coarse reconstructions of the vertebrae, enabling the construction of volume conductor models that include the neck. We exemplarily demonstrate that the extended models enable a more accurate estimation of the electric field distribution during transcranial direct current stimulation (tDCS) for montages that involve extraencephalic

  7. Head, Neck, and Oral Cancer

    Medline Plus

    Full Text Available ... out more. Oral, Head and Neck Pathology Oral, Head and Neck Pathology Close to 49,750 Americans ... out more. Oral, Head and Neck Pathology Oral, Head and Neck Pathology Close to 49,750 Americans ...

  8. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head uses ... of the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is a noninvasive medical ...

  9. CT Perfusion of the Head

    Science.gov (United States)

    ... Site Index A-Z CT Perfusion of the Head Computed tomography (CT) perfusion of the head uses ... the Head? What is CT Perfusion of the Head? Computed tomography (CT) perfusion imaging shows which areas ...

  10. Head, Neck, and Oral Cancer

    Medline Plus

    Full Text Available ... Head and Neck Pathology Oral, Head and Neck Pathology Close to 49,750 Americans will be diagnosed ... Head and Neck Pathology Oral, Head and Neck Pathology Close to 49,750 Americans will be diagnosed ...

  11. Porcine head response to blast

    Directory of Open Access Journals (Sweden)

    Jay eShridharani

    2012-05-01

    Full Text Available Recent studies have shown an increase in the frequency of traumatic brain injuries related to blast exposure. However, the mechanisms that cause blast neurotrauma are unknown. Blast neurotrauma research using computational models has been one method to elucidate that response of the brain in blast, and to identify possible mechanical correlates of injury. However, model validation against experimental data is required to ensure that the model output is representative of in vivo biomechanical response. This study exposed porcine subjects to primary blast overpressures generated using a compressed-gas shock tube. Shock tube blasts were directed to the unprotected head of each animal while the lungs and thorax were protected using ballistic protective vests similar to those employed in theater. The test conditions ranged from 110-740 kPa peak incident overpressure with scaled durations from 1.3-6.9 ms and correspond approximately with a 50% injury risk for brain bleeding and apnea in a ferret model scaled to porcine exposure. The bulk head acceleration and the pressure at the surface of the head and in the cranial cavity were measured. Immediately after the blast, 5 of the 20 animals tested were apneic. Three subjects recovered without intervention within thirty seconds and the remaining two recovered within 8 minutes following bagging and administration of the respiratory stimulant doxapram. Gross examination of the brain revealed no indication of bleeding. Intracranial pressures ranged from 80-685 kPa as a result of the blast and were notably lower than the shock tube reflected pressures of 300-2830 kPa, indicating pressure attenuation by the skull up to a factor of 8.4. Peak head accelerations were measured from 385-3845 G’s and were well correlated with peak incident overpressure (R2=0.90. One standard deviation corridors for the surface pressure, intracranial pressure, and head acceleration are presented to provide experimental data for

  12. SU-F-19A-10: Recalculation and Reporting Clinical HDR 192-Ir Head and Neck Dose Distributions Using Model Based Dose Calculation

    International Nuclear Information System (INIS)

    Carlsson Tedgren, A; Persson, M; Nilsson, J

    2014-01-01

    Purpose: To retrospectively re-calculate dose distributions for selected head and neck cancer patients, earlier treated with HDR 192Ir brachytherapy, using Monte Carlo (MC) simulations and compare results to distributions from the planning system derived using TG43 formalism. To study differences between dose to medium (as obtained with the MC code) and dose to water in medium as obtained through (1) ratios of stopping powers and (2) ratios of mass energy absorption coefficients between water and medium. Methods: The MC code Algebra was used to calculate dose distributions according to earlier actual treatment plans using anonymized plan data and CT images in DICOM format. Ratios of stopping power and mass energy absorption coefficients for water with various media obtained from 192-Ir spectra were used in toggling between dose to water and dose to media. Results: Differences between initial planned TG43 dose distributions and the doses to media calculated by MC are insignificant in the target volume. Differences are moderate (within 4–5 % at distances of 3–4 cm) but increase with distance and are most notable in bone and at the patient surface. Differences between dose to water and dose to medium are within 1-2% when using mass energy absorption coefficients to toggle between the two quantities but increase to above 10% for bone using stopping power ratios. Conclusion: MC predicts target doses for head and neck cancer patients in close agreement with TG43. MC yields improved dose estimations outside the target where a larger fraction of dose is from scattered photons. It is important with awareness and a clear reporting of absorbed dose values in using model based algorithms. Differences in bone media can exceed 10% depending on how dose to water in medium is defined

  13. Short-term effect of zoledronic acid upon fracture resistance of the mandibular condyle and femoral head in an animal model

    Science.gov (United States)

    López-Jornet, Pía; Vicente-Hernández, Ascensión

    2013-01-01

    Objective: The aim of this study was to compare the effects in terms of resistance to fracture of the mandibular condyle and femoral head following different doses of zoledronic acid in an animal model. Study design: A total of 80 adult male Sprague-Dawley rats were included in a prospective randomized study. The animals were randomly divided into four groups of 20 rats each. Group 1 (control) received sterile saline solution, while groups 2, 3 and 4 received a accumulated dose of 0.2 mg, 0.4 mg and 0.6 mg of zoledronic acid, respectively. The animals were sacrificed 28 days after the last dose, and the right hemimandible and the right femur were removed. The fracture strength was measured (in Newtons) with a universal test machine using a 1 kN load connected to a metal rod with one end angled at 30 degrees. The cross-head speed was 1 mm/min. Later, the specimens were observed under a scanning electron microscope with backscattered electron imaging (SEM-BSE). At last, chemical analysis and elemental mapping of the mineral bone composition were generated using a microanalytical system based on energy-dispersive and X-ray spectrometry (EDX). Results: A total of 160 fracture tests were performed. The fracture resistance increased in mandible and femur with a higher accumulated dose of zoledronic acid. Statistically significant differences were recorded versus the controls with all the studies groups. The chemical analysis in mandible showed a significantly increased of calcium and phosphorous to compare the control with all of the study groups; however, in femur no statistically significant differences between the four study groups were observed. Conclusions: The administration of bisphosphonates increases the fracture resistance in mandible and femur. Key words:Zoledronic acid, bisphosphonates, animal experimentation, fracture test. PMID:23524420

  14. Comparisons of peak SAR levels in concentric sphere head models of children and adults for irradiation by a dipole at 900 MHz

    International Nuclear Information System (INIS)

    Anderson, Vitas

    2003-01-01

    The aim of this study is to examine the scale and significance of differences in peak specific energy absorption rate (SAR) in the brains of children and adults exposed to radiofrequency emissions from mobile phones. Estimates were obtained by method of multipole analysis of a three layered (scalp/cranium/brain) spherical head exposed to a nearby 0.4 dipole at 900 MHz. A literature review of head parameters that influence SAR induction revealed strong indirect evidence based on total body water content that there are no substantive age-related changes in tissue conductivity after the first year of life. However, it was also found that the thickness of the ear, scalp and cranium do decrease on average with decreasing age, though individual variability within any age group is very high. The model analyses revealed that compared to an average adult, the peak brain 10 g averaged SAR in mean 4, 8, 12 and 16 year olds (yo) is increased by a factor of 1.31, 1.23, 1.15 and 1.07, respectively. However, contrary to the expectations of a recent prominent expert review, the UK Stewart Report, the relatively small scale of these increases does not warrant any special precautionary measures for child mobile phone users since: (a) SAR testing protocols as contained in the CENELEC (2001) standard provide an additional safety margin which ensures that allowable localized SAR limits are not exceeded in the brain; (b) the maximum worst case brain temperature rise (∼0.13 to 0.14 degrees C for an average 4 yo) in child users of mobile phones is well within safe levels and normal physiological parameters; and (c) the range of age average increases in children is less than the expected range of variation seen within the adult population

  15. Bone Circulatory Disturbances in the Development of Spontaneous Bacterial Chondronecrosis with Osteomyelitis: A Translational Model for the Pathogenesis of Femoral Head Necrosis

    Directory of Open Access Journals (Sweden)

    Robert F. Wideman

    2013-01-01

    Full Text Available This review provides a comprehensive overview of the vascularization of the avian growth plate and its subsequent role in the pathogenesis of bacterial chondronecrosis with osteomyelitis (BCO, femoral head necrosis. BCO sporadically causes high incidences of lameness in rapidly growing broiler (meat-type chickens. BCO is believed to be initiated by micro-trauma to poorly mineralized columns of cartilage cells in the proximal growth plates of the leg bones, followed by colonization by hematogenously distributed opportunistic bacteria. Inadequate blood flow to the growth plate, vascular occlusion, and structural limitations of the microvasculature all have been implicated in the pathogenesis of BCO. Treatment strategies have been difficult to investigate because under normal conditions the incidence of BCO typically is low and sporadic. Rearing broilers on wire flooring triggers the spontaneous development of high incidences of lameness attributable to pathognomonic BCO lesions. Wire flooring imposes persistent footing instability and is thought to accelerate the development of BCO by amplifying the torque and shear stress imposed on susceptible leg joints. Wire flooring per se also constitutes a significant chronic stressor that promotes bacterial proliferation attributed to stress-mediated immunosuppression. Indeed, dexamethasone-mediated immunosuppression causes broilers to develop lameness primarily associated with avascular necrosis and BCO. Prophylactic probiotic administration consistently reduces the incidence of lameness in broilers reared on wire flooring, presumably by reducing bacterial translocation from the gastrointestinal tract that likely contributes to hematogenous infection of the leg bones. The pathogenesis of BCO in broilers is directly relevant to osteomyelitis in growing children, as well as to avascular femoral head necrosis in adults. Our new model for reliably triggering spontaneous osteomyelitis in large numbers of

  16. An oral keratinocyte life cycle model identifies novel host genome regulation by human papillomavirus 16 relevant to HPV positive head and neck cancer.

    Science.gov (United States)

    Evans, Michael R; James, Claire D; Loughran, Oonagh; Nulton, Tara J; Wang, Xu; Bristol, Molly L; Windle, Brad; Morgan, Iain M

    2017-10-10

    Many aspects of the HPV life cycle have been characterized in cervical cell lines (W12, CIN612) and in HPV immortalized primary foreskin keratinocytes. There is now an epidemic of HPV positive oropharyngeal cancers (HPV16 is responsible for 80-90% of these); therefore increased understanding of the HPV16 life cycle in oral keratinocytes is a priority. To date there have been limited reports characterizing the HPV16 life cycle in oral keratinocytes. Using TERT immortalized "normal" oral keratinocytes (NOKs) we generated clonal cell lines maintaining the HPV16 genome as an episome, NOKs+HPV16. Organotypic raft cultures demonstrated appropriate expression of differentiation markers, E1^E4 and E2 expression along with amplification of the viral genome in the upper layers of the epithelium. Using this unique system RNA-seq analysis revealed extensive gene regulation of the host genome by HPV16; many of the changes have not been observed for HPV16 before. The RNA-seq data was validated on a key set of anti-viral innate immune response genes repressed by HPV16 in NOKs+HPV16. We show that the behavior of these NOKs+HPV16 lines is identical to HPV16 immortalized human tonsil keratinocytes with regards innate gene regulation. Finally, using The Cancer Genome Atlas (TCGA) data we examined gene expression patterns from HPV positive and negative head and neck cancers and demonstrate this innate immune gene signature set is also downregulated in HPV positive cancers versus negative. Our system provides a model for understanding HPV16 transcriptional regulation of oral keratinocytes that is directly relevant to HPV positive head and neck cancer.

  17. GPU-Powered Modelling of Nonlinear Effects due to Head-On Beam-Beam Interactions in High-Energy Hadron Colliders.

    CERN Document Server

    Furuseth, Sondre

    2017-01-01

    The performance of high-energy circular hadron colliders, as the Large Hadron Collider, is limited by beam-beam interactions. The strongly nonlinear force between the two opposing beams causes diverging Hamiltonians and resonances, which can lead to a reduction of the lifetime of the beams. The nonlinearity makes the effect of the force difficult to study analytically, even at first order. Numerical models are therefore needed to evaluate the overall effect of different configurations of the machines. This report discusses results from an implementation of the weak-strong model, studying the effects of head-on beam-beam interactions. The assumptions has been shown to be valid for configurations where the growth and losses of the beam are small. The tracking has been done using an original code which applies graphic cards to reduce the computation time. The bunches in the beams have been modelled cylindrically symmetrical, based on a Gaussian distribution in three dimensions. This choice fits well with bunches...

  18. HGF-transgenic MSCs can improve the effects of tissue self-repair in a rabbit model of traumatic osteonecrosis of the femoral head.

    Directory of Open Access Journals (Sweden)

    Qian Wen

    Full Text Available BACKGROUND: Osteonecrosis of the femoral head (ONFH is generally characterized as an irreversible disease and tends to cause permanent disability. Therefore, understanding the pathogenesis and molecular mechanisms of ONFH and developing effective therapeutic methods is critical for slowing the progress of the disease. METHODOLOGY/PRINCIPAL FINDINGS: In this study, an experimental rabbit model of early stage traumatic ONFH was established, validated, and used for an evaluation of therapy. Computed tomography (CT and magnetic resonance (MR imaging confirmed that this model represents clinical Association Research Circulation Osseous (ARCO phase I or II ONFH, which was also confirmed by the presence of significant tissue damage in osseous tissue and vasculature. Pathological examination detected obvious self-repair of bone tissue up to 2 weeks after trauma, as indicated by revascularization (marked by CD105 and expression of collagen type I (Col I, osteocalcin, and proliferating cell nuclear antigen. Transplantation of hepatocyte growth factor (HGF-transgenic mesenchymal stem cells (MSCs 1 week after trauma promoted recovery from ONFH, as evidenced by a reversed pattern of Col I expression compared with animals receiving no therapeutic treatment, as well as increased expression of vascular endothelial growth factor. CONCLUSIONS/SIGNIFICANCE: These results indicate that the transplantation of HGF-transgenic MSCs is a promising method for the treatment for ONFH and suggest that appropriate interference therapy during the tissue self-repair stage contributes to the positive outcomes. This study also provides a model for the further study of the ONFH etiology and therapeutic interventions.

  19. EFFECTS OF COOPERATIVE LEARNING MODEL TYPE NUMBERED HEADS TOGETHER USING SIMULATION MEDIA PHET AND ACTIVITIES TOWARD STUDENT RESULTS

    Directory of Open Access Journals (Sweden)

    Fitri Mawaddah Lubis

    2015-12-01

    Full Text Available This study aimed to analyze the differences in learning outcomes of students taught by cooperative learning model NHT using simulation PhET and conventional learning, analyzing the differences in learning outcomes of students who have high activity and low activity, as well as the  interaction between learning model with the level of student activity in  influencing the outcome students learn physics. This research is a quasi experimental. The population in this study were students of class X SMK Tritech Informatika Medan. The tests were used to obtain the data is in the form of multiple choice. Test requirements have been carried out in the form of normality and homogeneity, which showed that the normal data and homogeneous. The data were analyzed using Anova analysis of two paths. The results showed that: The physics learning outcomes of students who use cooperative learning model NHT using PhET simulations media is better than students who use conventional learning models. The physics learning outcomes of students who have high learning activities is better than students who have Low learning activities. There is an interaction between cooperative learning model NHT PhET simulations using the media and the level of learning activity in influencing student learning outcomes. Average increase learning outcomes in the control class is greater than the experimental class.

  20. The Implementation of Cooperative Learning Model "Number Heads Together" ("NHT") in Improving the Students' Ability in Reading Comprehension

    Science.gov (United States)

    Maman, Mayong; Rajab, Andi Aryani

    2016-01-01

    The study aimed at describing the implementation of cooperative learning model of (NHT) at student of SMPN 2 Maros. The method used was a classroom action research in two cycles. Data were collected using the test for the quantitative and non-test for the qualitative by employing observation, field note, student's workbook, student's reflection…

  1. SU-F-R-41: Regularized PCA Can Model Treatment-Related Changes in Head and Neck Patients Using Daily CBCTs

    Energy Technology Data Exchange (ETDEWEB)

    Chetvertkov, M [Wayne State University, Detroit, MI (United States); Henry Ford Health System, Detroit, MI (United States); Siddiqui, F; Chetty, I; Kumarasiri, A; Liu, C; Gordon, J [Henry Ford Health System, Detroit, MI (United States)

    2016-06-15

    Purpose: To use daily cone beam CTs (CBCTs) to develop regularized principal component analysis (PCA) models of anatomical changes in head and neck (H&N) patients, to guide replanning decisions in adaptive radiation therapy (ART). Methods: Known deformations were applied to planning CT (pCT) images of 10 H&N patients to model several different systematic anatomical changes. A Pinnacle plugin was used to interpolate systematic changes over 35 fractions, generating a set of 35 synthetic CTs for each patient. Deformation vector fields (DVFs) were acquired between the pCT and synthetic CTs and random fraction-to-fraction changes were superimposed on the DVFs. Standard non-regularized and regularized patient-specific PCA models were built using the DVFs. The ability of PCA to extract the known deformations was quantified. PCA models were also generated from clinical CBCTs, for which the deformations and DVFs were not known. It was hypothesized that resulting eigenvectors/eigenfunctions with largest eigenvalues represent the major anatomical deformations during the course of treatment. Results: As demonstrated with quantitative results in the supporting document regularized PCA is more successful than standard PCA at capturing systematic changes early in the treatment. Regularized PCA is able to detect smaller systematic changes against the background of random fraction-to-fraction changes. To be successful at guiding ART, regularized PCA should be coupled with models of when anatomical changes occur: early, late or throughout the treatment course. Conclusion: The leading eigenvector/eigenfunction from the both PCA approaches can tentatively be identified as a major systematic change during radiotherapy course when systematic changes are large enough with respect to random fraction-to-fraction changes. In all cases the regularized PCA approach appears to be more reliable at capturing systematic changes, enabling dosimetric consequences to be projected once trends are

  2. SU-F-R-41: Regularized PCA Can Model Treatment-Related Changes in Head and Neck Patients Using Daily CBCTs

    International Nuclear Information System (INIS)

    Chetvertkov, M; Siddiqui, F; Chetty, I; Kumarasiri, A; Liu, C; Gordon, J

    2016-01-01

    Purpose: To use daily cone beam CTs (CBCTs) to develop regularized principal component analysis (PCA) models of anatomical changes in head and neck (H&N) patients, to guide replanning decisions in adaptive radiation therapy (ART). Methods: Known deformations were applied to planning CT (pCT) images of 10 H&N patients to model several different systematic anatomical changes. A Pinnacle plugin was used to interpolate systematic changes over 35 fractions, generating a set of 35 synthetic CTs for each patient. Deformation vector fields (DVFs) were acquired between the pCT and synthetic CTs and random fraction-to-fraction changes were superimposed on the DVFs. Standard non-regularized and regularized patient-specific PCA models were built using the DVFs. The ability of PCA to extract the known deformations was quantified. PCA models were also generated from clinical CBCTs, for which the deformations and DVFs were not known. It was hypothesized that resulting eigenvectors/eigenfunctions with largest eigenvalues represent the major anatomical deformations during the course of treatment. Results: As demonstrated with quantitative results in the supporting document regularized PCA is more successful than standard PCA at capturing systematic changes early in the treatment. Regularized PCA is able to detect smaller systematic changes against the background of random fraction-to-fraction changes. To be successful at guiding ART, regularized PCA should be coupled with models of when anatomical changes occur: early, late or throughout the treatment course. Conclusion: The leading eigenvector/eigenfunction from the both PCA approaches can tentatively be identified as a major systematic change during radiotherapy course when systematic changes are large enough with respect to random fraction-to-fraction changes. In all cases the regularized PCA approach appears to be more reliable at capturing systematic changes, enabling dosimetric consequences to be projected once trends are

  3. Prediction of outcome after moderate and severe traumatic brain injury: External validation of the International Mission on Prognosis and Analysis of Clinical Trials (IMPACT) and Corticoid Randomisation after Significant Head injury (CRASH) prognostic models

    NARCIS (Netherlands)

    B. Roozenbeek (Bob); H.F. Lingsma (Hester); F.E. Lecky (Fiona); J. Lu (Juan); J. Weir (James); I. Butcher (Isabella); G.S. McHugh (Gillian); G.D. Murray (Gordon); P. Perel (Pablo); A.I.R. Maas (Andrew); E.W. Steyerberg (Ewout)

    2012-01-01

    textabstractObjective: The International Mission on Prognosis and Analysis of Clinical Trials and Corticoid Randomisation After Significant Head injury prognostic models predict outcome after traumatic brain injury but have not been compared in large datasets. The objective of this is study is to

  4. The Effective Convectivity Model for Simulation of Molten Metal Layer Heat Transfer in a Boiling Water Reactor Lower Head

    Directory of Open Access Journals (Sweden)

    Chi-Thanh Tran

    2013-01-01

    Full Text Available This paper is concerned with the development of approaches for assessment of core debris heat transfer and Control Rod Guide Tube (CRGT cooling effectiveness in case of a Boiling Water Reactor (BWR severe accident. We consider a hypothetical scenario with stratified (metal layer atop melt pool in the lower plenum. Effective Convectivity Model (ECM and Phase-Change ECM (PECM are developed for the modeling of molten metal layer heat transfer. The PECM model takes into account reduced convection heat transfer in mushy zone and compositional convection that enables simulations of noneutectic binary mixture solidification and melting. The ECM and PECM are (i validated against relevant experiments for both eutectic and noneutectic mixtures and (ii benchmarked against CFD-generated data including the local heat transfer characteristics. The PECM is then applied to the analysis of heat transfer in a stratified heterogeneous debris pool taking into account CRGT cooling. The PECM simulation results show apparent efficacy of the CRGT cooling which can be utilized as Severe Accident Management (SAM measure to protect the vessel wall from focusing effect caused by metallic layer.

  5. Spectra and neutron dose of an 18 MV Linac using two geometric models of the head; Espectros y dosis por neutrones de un Linac de 18 MV usando dos modelos geometricos del cabezal

    Energy Technology Data Exchange (ETDEWEB)

    Barrera, M. T.; Pino, F.; Barros, H.; Sajo-Bohus, L. [Universidad Simon Bolivar, Laboratorio de Fisica Nuclear, Sartenejas, Baruta 1080-A, Caracas (Venezuela, Bolivarian Republic of); Davila, J. [Fisica Medica C. A., Av. Francisco de Miranda s/n, Los Palos Grandes, 1060 Miranda (Venezuela, Bolivarian Republic of); Salcedo, E. [Centro Medico Docente La Trinidad, Av. de El Haltillo, Caracas (Venezuela, Bolivarian Republic of); Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico); Benites R, J. L., E-mail: mariate9590@gmail.com [Centro de Cancerologia de Nayarit, Servicio de Seguridad Radiologica, Calz. de la Cruz 118 Sur, 63000 Tepic, Nayarit (Mexico)

    2015-10-15

    Full text: Using the Monte Carlo method, by MCNP5 code, simulations were performed with different source terms and 2 geometric models of the head to obtain spectra in energy, flow and doses of photo-neutrons at different positions on the stretcher and in the radiotherapy room. The simplest model was a spherical shell of tungsten; the second was the complete model of a heterogeneous head of an accelerator Varian ix. In both models Tosi function was used as a source term. In addition, for the second model Sheikh-Bagheri distribution was used for photons and photo-neutrons were generated. Also in both models the radiotherapy room of Gurve group of the Teaching Medical Center La Trinidad was included, which is equipped with an accelerator Varian Clinic 2100. In this Center passive detectors PADC (Cr-39) were irradiated with neutron converters, with 18 MeV photons radiation. The measured neutron flow was compared with that obtained with Monte Carlo calculations. The Monte Carlo flows are similar to those measured at the isocenter. The simplest model underestimates the neutron flow compared with the calculated flows with the heterogeneous model of the head. (Author)

  6. Head Injuries in Soccer.

    Science.gov (United States)

    Myrick, Karen M

    2016-07-01

    Soccer is currently the most popular and fastest growing sport worldwide, with approximately 265 million registered soccer players existing around the world. The popularity of the sport, coupled with the high incidence of 18.8-21.5 head injuries per 1,000 player hours reported, make it essential that clinicians, coaches, and the athletes, have a solid understanding of head injuries. The successful rehabilitation of athletes with head injuries relies upon early and accurate identification strategies and implementation of appropriate return to play measures across all areas in the continuum of care. Soccer is a frequently played sport, and head injuries are common. Therefore, it is imperative that clinicians, coaches, and the athletes themselves have a solid understanding of head injury prevention, diagnosis, and treatment options. The purpose of this article was to provide rehabilitation nurses with current information regarding frequently occurring head injuries in the widespread sport of soccer. © 2015 Association of Rehabilitation Nurses.

  7. Head and Neck

    DEFF Research Database (Denmark)

    Højgaard, Liselotte; Berthelsen, Anne Kiil; Loft, Annika

    2014-01-01

    Positron emission tomography (PET)/computed tomography with FDG of the head and neck region is mainly used for the diagnosis of head and neck cancer, for staging, treatment evaluation, relapse, and planning of surgery and radio therapy. This article is a practical guide of imaging techniques......, including a detailed protocol for FDG PET in head and neck imaging, physiologic findings, and pitfalls in selected case stories....

  8. Head development. Craniofacial genetics makes headway.

    Science.gov (United States)

    Richman, J M

    1995-04-01

    Studies of neural crest migration in animal models, and of human syndromes in which craniofacial development is abnormal, are helping us to understand both prenatal and postnatal development of the head.

  9. Scheduling cisplatin and radiotherapy in the treatment of squamous cell carcinomas of the head and neck: a modelling approach

    International Nuclear Information System (INIS)

    Marcu, L; Bezak, E; Olver, I

    2006-01-01

    The aim of the present work was to implement the kinetics of cisplatin into a previously developed tumour growth model and to simulate the combined cisplatin-radiotherapy treatment with the emphasis on time sequencing and scheduling of drug and radiation. An investigation into whether the effect of cisplatin-radiation is determined by independent cell kill or by cisplatin-produced radiosensitization was also undertaken. It was shown that cisplatin administered before radiation conferred similar tumour control to the post-radiation sequencing of the drug. The killing effect of the combined modality treatment on tumour increased with the increase in cell recruitment. Furthermore, the individual cell kill produced by the two cytotoxins led to an additive only tumour response when the treatments were given concurrently, suggesting that for a synergistic effect, cisplatin must potentiate the effect of radiation, through the radiosensitizing mechanisms addressed in the literature. It was concluded that the optimal timing of cisplatin should be close to radiation. The model showed that daily administration of cisplatin led to a 35% improvement of tumour control as compared to radiation alone, while weekly cisplatin has improved radiotherapy by only 6%

  10. Bottom head assembly

    International Nuclear Information System (INIS)

    Fife, A.B.

    1998-01-01

    A bottom head dome assembly is described which includes, in one embodiment, a bottom head dome and a liner configured to be positioned proximate the bottom head dome. The bottom head dome has a plurality of openings extending there through. The liner also has a plurality of openings extending there through, and each liner opening aligns with a respective bottom head dome opening. A seal is formed, such as by welding, between the liner and the bottom head dome to resist entry of water between the liner and the bottom head dome at the edge of the liner. In the one embodiment, a plurality of stub tubes are secured to the liner. Each stub tube has a bore extending there through, and each stub tube bore is coaxially aligned with a respective liner opening. A seat portion is formed by each liner opening for receiving a portion of the respective stub tube. The assembly also includes a plurality of support shims positioned between the bottom head dome and the liner for supporting the liner. In one embodiment, each support shim includes a support stub having a bore there through, and each support stub bore aligns with a respective bottom head dome opening. 2 figs

  11. Head-On Beam-Beam Interactions in High-Energy Hadron Colliders. GPU-Powered Modelling of Nonlinear Effects

    CERN Document Server

    AUTHOR|(CDS)2160109; Støvneng, Jon Andreas

    2017-08-15

    The performance of high-energy circular hadron colliders, as the Large Hadron Collider, is limited by beam-beam interactions. The strength of the beam-beam interactions will be higher after the upgrade to the High-Luminosity Large Hadron Collider, and also in the next generation of machines, as the Future Circular Hadron Collider. The strongly nonlinear force between the two opposing beams causes diverging Hamiltonians and drives resonances, which can lead to a reduction of the lifetime of the beams. The nonlinearity makes the effect of the force difficult to study analytically, even at first order. Numerical models are therefore needed to evaluate the overall effect of different configurations of the machines. For this thesis, a new code named CABIN (Cuda-Accelerated Beam-beam Interaction) has been developed to study the limitations caused by the impact of strong beam-beam interactions. In particular, the evolution of the beam emittance and beam intensity has been monitored to study the impact quantitatively...

  12. Comparison and modeling of households food expenditures in Slovakia with regard to the economic status and job position of the head of household

    Directory of Open Access Journals (Sweden)

    Ľubica Kubicová

    2013-01-01

    Full Text Available Paper focuses on analysis and development of nominal and real cash income as well as modeling of real cash household food expenditures in Slovakia. From the view of the head of household and his job position, paper compares the level and development of real money incomes and food expenditures, in terms of real money incomes quantifies the income elasticity and available demand saturation level for food in families of employees, self-employed persons and pensioners. Generally expected outcome of economic growth is raising standard of living of the population. Its measurement is based on the basic macroeconomic aggregates such as GDP growth and GDP per capita. Such indicators, despite their clearly accepted significance, have a number of limitations that undermine their informational value. These indicators are the product of highly aggregated data. Therefore submitted paper focuses on the analysis of the income situation of the population. This approach allows to obtain objective indicators of the true state income differentiation, respectively income inequality in particular social groups. Society with substantial income differentiation is less resistant against various extreme impact of globalization. The analysis results show that in the years 2004–2011 the real income increased least in the group of self-employed persons by an average of 4.89% (k’ = 1.0489, while in the group of pensioners, the real income increased by an average of 7.08 % (k’ = 1.0708.

  13. Development of body, head and brain features in the Australian fat-tailed dunnart (Sminthopsis crassicaudata; Marsupialia: Dasyuridae); A postnatal model of forebrain formation.

    Science.gov (United States)

    Suárez, Rodrigo; Paolino, Annalisa; Kozulin, Peter; Fenlon, Laura R; Morcom, Laura R; Englebright, Robert; O'Hara, Patricia J; Murray, Peter J; Richards, Linda J

    2017-01-01

    Most of our understanding of forebrain development comes from research of eutherian mammals, such as rodents, primates, and carnivores. However, as the cerebral cortex forms largely prenatally, observation and manipulation of its development has required invasive and/or ex vivo procedures. Marsupials, on the other hand, are born at comparatively earlier stages of development and most events of forebrain formation occur once attached to the teat, thereby permitting continuous and non-invasive experimental access. Here, we take advantage of this aspect of marsupial biology to establish and characterise a resourceful laboratory model of forebrain development: the fat-tailed dunnart (Sminthopsis crassicaudata), a mouse-sized carnivorous Australian marsupial. We present an anatomical description of the postnatal development of the body, head and brain in dunnarts, and provide a staging system compatible with human and mouse developmental stages. As compared to eutherians, the orofacial region develops earlier in dunnarts, while forebrain development is largely protracted, extending for more than 40 days versus ca. 15 days in mice. We discuss the benefits of fat-tailed dunnarts as laboratory animals in studies of developmental biology, with an emphasis on how their accessibility in the pouch can help address new experimental questions, especially regarding mechanisms of brain development and evolution.

  14. Spatio-temporal EEG source localization using a three-dimensional subspace FINE approach in a realistic geometry inhomogeneous head model.

    Science.gov (United States)

    Ding, Lei; He, Bin

    2006-09-01

    The subspace source localization approach, i.e., first principle vectors (FINE), is able to enhance the spatial resolvability and localization accuracy for closely-spaced neural sources from EEG and MEG measurements. Computer simulations were conducted to evaluate the performance of the FINE algorithm in an inhomogeneous realistic geometry head model under a variety of conditions. The source localization abilities of FINE were examined at different cortical regions and at different depths. The present computer simulation results indicate that FINE has enhanced source localization capability, as compared with MUSIC and RAP-MUSIC, when sources are closely spaced, highly noise-contaminated, or inter-correlated. The source localization accuracy of FINE is better, for closely-spaced sources, than MUSIC at various noise levels, i.e., signal-to-noise ratio (SNR) from 6 dB to 16 dB, and RAP-MUSIC at relatively low noise levels, i.e., 6 dB to 12 dB. The FINE approach has been further applied to localize brain sources of motor potentials, obtained during the finger tapping tasks in a human subject. The experimental results suggest that the detailed neural activity distribution could be revealed by FINE. The present study suggests that FINE provides enhanced performance in localizing multiple closely spaced, and inter-correlated sources under low SNR, and may become an important alternative to brain source localization from EEG or MEG.

  15. Combination of thalidomide and cisplatin in an head and neck squamous cell carcinomas model results in an enhanced antiangiogenic activity in vitro and in vivo.

    Science.gov (United States)

    Vasvari, Gergely P; Dyckhoff, Gerhard; Kashfi, Farzaneh; Lemke, Britt; Lohr, Jennifer; Helmke, Burkhard M; Schirrmacher, Volker; Plinkert, Peter K; Beckhove, Philipp; Herold-Mende, Christel C

    2007-10-15

    Thalidomide is an immunomodulatory, antiangiogenic drug. Although there is evidence that it might be more effective in combination with chemotherapy the exact mechanism of action is unclear. Therefore, we investigated its effect in combination with metronomically applied cisplatin in a xenotransplant mouse model characteristic for advanced head and neck squamous cell carcinomas, its possible synergistic action in vitro, and which tumor-derived factors might be targeted by thalidomide. Although thalidomide alone was ineffective, a combined treatment with low-dose cisplatin inhibited significant tumor growth, proliferation and angiogenesis in vivo as well as migration and tube formation of endothelial cells in vitro. Noteworthy, the latter effect was enhanced after coapplication of cisplatin in nontoxic doses. An inhibitory effect on tumor cell migration was also observed suggesting a direct antitumor effect. Although thalidomide alone did not influence cell proliferation, it augmented antiproliferative response after cisplatin application emphasizing the idea of a potentiated effect when both drugs are combined. Furthermore, we could show that antiangiogenic effects of thalidomide are related to tumor-cell derived factors including vascular endothelial growth factor, basic fibroblast growth factor, hepatocyte growth factor and Il-8 some known and with, granulocyte colony stimulating growth factor and granulocyte macrophage colony stimulating growth factor, some new target molecules of thalidomide. Altogether, our findings reveal new insights into thalidomide-mediated antitumor and antiangiogenic effects and its interaction with cytostatic drugs. (c) 2007 Wiley-Liss, Inc.

  16. SU-E-T-580: On the Significance of Model Based Dosimetry for Breast and Head and Neck 192Ir HDR Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Peppa, V; Pappas, E; Pantelis, E; Papagiannis, P [Medical Physics Laboratory, Medical School, University of Athens, Athens (Greece); Major, T; Polgar, C [National Institute of Oncology, Budapest (Hungary)

    2015-06-15

    Purpose: To assess the dosimetric and radiobiological differences between TG43-based and model-based dosimetry in the treatment planning of {sup 192}Ir HDR brachytherapy for breast and head and neck cancer. Methods: Two cohorts of 57 Accelerated Partial Breast Irradiation (APBI) and 22 head and neck (H&N) patients with oral cavity carcinoma were studied. Dosimetry for the treatment plans was performed using the TG43 algorithm of the Oncentra Brachy v4.4 treatment planning system (TPS). Corresponding Monte Carlo (MC) simulations were performed using MCNP6 with input files automatically prepared by the BrachyGuide software tool from DICOM RT plan data. TG43 and MC data were compared in terms of % dose differences, Dose Volume Histograms (DVHs) and related indices of clinical interest for the Planning Target Volume (PTV) and the Organs-At-Risk (OARs). A radiobiological analysis was also performed using the Equivalent Uniform Dose (EUD), mean survival fraction (S) and Tumor Control Probability (TCP) for the PTV, and the Normal Tissue Control Probability (N TCP) and the generalized EUD (gEUD) for the OARs. Significance testing of the observed differences performed using the Wilcoxon paired sample test. Results: Differences between TG43 and MC DVH indices, associated with the increased corresponding local % dose differences observed, were statistically significant. This is mainly attributed to their consistency however, since TG43 agrees closely with MC for the majority of DVH and radiobiological parameters in both patient cohorts. Differences varied considerably among patients only for the ipsilateral lung and ribs in the APBI cohort, with a strong correlation to target location. Conclusion: While the consistency and magnitude of differences in the majority of clinically relevant DVH indices imply that no change is needed in the treatment planning practice, individualized dosimetry improves accuracy and addresses instances of inter-patient variability observed. Research

  17. SU-E-T-580: On the Significance of Model Based Dosimetry for Breast and Head and Neck 192Ir HDR Brachytherapy

    International Nuclear Information System (INIS)

    Peppa, V; Pappas, E; Pantelis, E; Papagiannis, P; Major, T; Polgar, C

    2015-01-01

    Purpose: To assess the dosimetric and radiobiological differences between TG43-based and model-based dosimetry in the treatment planning of 192 Ir HDR brachytherapy for breast and head and neck cancer. Methods: Two cohorts of 57 Accelerated Partial Breast Irradiation (APBI) and 22 head and neck (H&N) patients with oral cavity carcinoma were studied. Dosimetry for the treatment plans was performed using the TG43 algorithm of the Oncentra Brachy v4.4 treatment planning system (TPS). Corresponding Monte Carlo (MC) simulations were performed using MCNP6 with input files automatically prepared by the BrachyGuide software tool from DICOM RT plan data. TG43 and MC data were compared in terms of % dose differences, Dose Volume Histograms (DVHs) and related indices of clinical interest for the Planning Target Volume (PTV) and the Organs-At-Risk (OARs). A radiobiological analysis was also performed using the Equivalent Uniform Dose (EUD), mean survival fraction (S) and Tumor Control Probability (TCP) for the PTV, and the Normal Tissue Control Probability (N TCP) and the generalized EUD (gEUD) for the OARs. Significance testing of the observed differences performed using the Wilcoxon paired sample test. Results: Differences between TG43 and MC DVH indices, associated with the increased corresponding local % dose differences observed, were statistically significant. This is mainly attributed to their consistency however, since TG43 agrees closely with MC for the majority of DVH and radiobiological parameters in both patient cohorts. Differences varied considerably among patients only for the ipsilateral lung and ribs in the APBI cohort, with a strong correlation to target location. Conclusion: While the consistency and magnitude of differences in the majority of clinically relevant DVH indices imply that no change is needed in the treatment planning practice, individualized dosimetry improves accuracy and addresses instances of inter-patient variability observed. Research co

  18. Electric field estimation of deep transcranial magnetic stimulation clinically used for the treatment of neuropsychiatric disorders in anatomical head models.

    Science.gov (United States)

    Parazzini, Marta; Fiocchi, Serena; Chiaramello, Emma; Roth, Yiftach; Zangen, Abraham; Ravazzani, Paolo

    2017-05-01

    Literature studies showed the ability to treat neuropsychiatric disorders using H1 coil, developed for the deep Transcranial Magnetic Stimulation (dTMS). Despite the positive results of the clinical studies, the electric field (E) distributions inside the brain induced by this coil when it is positioned on the scalp according to the clinical studies themselves are not yet precisely estimated. This study aims to characterize the E distributions due to the H1 coil in the brain of two realistic human models by computational electromagnetic techniques and to compare them with the ones due to the figure-of-8 coil, traditionally used in TMS and positioned as such to simulate the clinical experiments. Despite inter-individual differences, our results show that the dorsolateral prefrontal cortex is the region preferentially stimulated by both H1 and figure-of-8 coil when they are placed in the position on the scalp according to the clinical studies, with a more broad and non-focal distribution in the case of H1 coil. Moreover, the H1 coil spreads more than the figure-of-8 coil both in the prefrontal cortex and medial prefrontal cortex and towards some deeper brain structures and it is characterized by a higher penetration depth in the frontal lobe. This work highlights the importance of the knowledge of the electric field distribution in the brain tissues to interpret the outcomes of the experimental studies and to optimize the treatments. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

  19. SU-E-J-257: A PCA Model to Predict Adaptive Changes for Head&neck Patients Based On Extraction of Geometric Features From Daily CBCT Datasets

    International Nuclear Information System (INIS)

    Chetvertkov, M; Siddiqui, F; Chetty, I; Kim, J; Kumarasiri, A; Liu, C; Gordon, J

    2015-01-01

    Purpose: Using daily cone beam CTs (CBCTs) to develop principal component analysis (PCA) models of anatomical changes in head and neck (H&N) patients and to assess the possibility of using these prospectively in adaptive radiation therapy (ART). Methods: Planning CT (pCT) images of 4 H&N patients were deformed to model several different systematic changes in patient anatomy during the course of the radiation therapy (RT). A Pinnacle plugin was used to linearly interpolate the systematic change in patient for the 35 fraction RT course and to generate a set of 35 synthetic CBCTs. Each synthetic CBCT represents the systematic change in patient anatomy for each fraction. Deformation vector fields (DVFs) were acquired between the pCT and synthetic CBCTs with random fraction-to-fraction changes were superimposed on the DVFs. A patient-specific PCA model was built using these DVFs containing systematic plus random changes. It was hypothesized that resulting eigenDVFs (EDVFs) with largest eigenvalues represent the major anatomical deformations during the course of treatment. Results: For all 4 patients, the PCA model provided different results depending on the type and size of systematic change in patient’s body. PCA was more successful in capturing the systematic changes early in the treatment course when these were of a larger scale with respect to the random fraction-to-fraction changes in patient’s anatomy. For smaller scale systematic changes, random changes in patient could completely “hide” the systematic change. Conclusion: The leading EDVF from the patientspecific PCA models could tentatively be identified as a major systematic change during treatment if the systematic change is large enough with respect to random fraction-to-fraction changes. Otherwise, leading EDVF could not represent systematic changes reliably. This work is expected to facilitate development of population-based PCA models that can be used to prospectively identify significant

  20. NTCP models for patient-rated xerostomia and sticky saliva after treatment with intensity modulated radiotherapy for head and neck cancer: The role of dosimetric and clinical factors

    International Nuclear Information System (INIS)

    Beetz, Ivo; Schilstra, Cornelis; Schaaf, Arjen van der; Heuvel, Edwin R. van den; Doornaert, Patricia; Luijk, Peter van; Vissink, Arjan; Laan, Bernard F.A.M. van der; Leemans, Charles R.; Bijl, Henk P.; Christianen, Miranda E.M.C.; Steenbakkers, Roel J.H.M.; Langendijk, Johannes A.

    2012-01-01

    Purpose: The purpose of this multicentre prospective study was to develop multivariable logistic regression models to make valid predictions about the risk of moderate-to-severe patient-rated xerostomia (XER M6 ) and sticky saliva 6 months (STIC M6 ) after primary treatment with intensity modulated radiotherapy (IMRT) with or without chemotherapy for head and neck cancer (HNC). Methods and materials: The study population was composed of 178 consecutive HNC patients treated with IMRT. All patients were included in a standard follow up programme in which acute and late side effects and quality of life were prospectively assessed, prior to, during and after treatment. The primary endpoints were XER M6 and STIC M6 as assessed by the EORTC QLQ-H and N35 after completing IMRT. Organs at risk (OARs) potentially involved in salivary function were delineated on planning-CT, including the parotid, submandibular and sublingual glands and the minor glands in the soft palate, cheeks and lips. Patients with moderate-to-severe xerostomia or sticky saliva, respectively, at baseline were excluded. The optimal number of variables for a multivariate logistic regression model was determined using a bootstrapping method. Results: Eventually, 51.6% of the cases suffered from XER M6 . The multivariate analysis showed that the mean contralateral parotid gland dose and baseline xerostomia (none vs. a bit) were the most important predictors for XER M6 . For the multivariate NTCP model, the area under the receiver operating curve (AUC) was 0.68 (95% CI 0.60–0.76) and the discrimination slope was 0.10, respectively. Calibration was good with a calibration slope of 1.0. At 6 months after IMRT, 35.6% of the cases reported STIC M6 . The mean contralateral submandibular gland dose, the mean sublingual dose and the mean dose to the minor salivary glands located in the soft palate were most predictive for STIC M6 . For this model, the AUC was 0.70 (95% CI 0.61–0.78) and the discrimination slope

  1. Head, neck, and body coupling in reconstructions of helmeted head impacts

    NARCIS (Netherlands)

    Lange, R. de; Cappon, H.J.; Beusenberg, C.M.; Shewchenko, N.; Newman, J.A.

    2001-01-01

    A mathematical modeling study is conducted to investigate neck coupling in helmeted head impacts. The main objective of the study is to provide direction for the experimental reconstruction of American football player impacts. Head responses are compared in MADYMO simulations of various impact

  2. Head Injuries in Children

    Science.gov (United States)

    Pennington, Nicole

    2010-01-01

    School nurses play a crucial role in injury prevention and initial treatment when injuries occur at school. The role of school nurses includes being knowledgeable about the management of head injuries, including assessment and initial treatment. The school nurse must be familiar with the outcomes of a head injury and know when further evaluation…

  3. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... Computed tomography (CT) of the head uses special x-ray equipment to help assess head injuries, severe headaches, ... is a diagnostic medical test that, like traditional x-rays, produces multiple images or pictures of the inside ...

  4. The Effective Convectivity Model for Simulation and Analysis of Melt Pool Heat Transfer in a Light Water Reactor Pressure Vessel Lower Head

    International Nuclear Information System (INIS)

    Tran, Chi Thanh

    2009-09-01

    Severe accidents in a Light Water Reactor (LWR) have been a subject of intense research for the last three decades. The research in this area aims to reach understanding of the inherent physical phenomena and reduce the uncertainties in their quantification, with the ultimate goal of developing models that can be applied to safety analysis of nuclear reactors, and to evaluation of the proposed accident management schemes for mitigating the consequences of severe accidents. In a hypothetical severe accident there is likelihood that the core materials will be relocated to the lower plenum and form a decay-heated debris bed (debris cake) or a melt pool. Interactions of core debris or melt with the reactor structures depend to a large extent on the debris bed or melt pool thermal hydraulics. In case of inadequate cooling, the excessive heat would drive the structures' overheating and ablation, and hence govern the vessel failure mode and timing. In turn, threats to containment integrity associated with potential ex-vessel steam explosions and ex-vessel debris uncoolability depend on the composition, superheat, and amount of molten corium available for discharge upon the vessel failure. That is why predictions of transient melt pool heat transfer in the reactor lower head, subsequent vessel failure modes and melt characteristics upon the discharge are of paramount importance for plant safety assessment. The main purpose of the present study is to develop a method for reliable prediction of melt pool thermal hydraulics, namely to establish a computational platform for cost-effective, sufficiently-accurate numerical simulations and analyses of core Melt-Structure-Water Interactions in the LWR lower head during a postulated severe core-melting accident. To achieve the goal, an approach to efficient use of Computational Fluid Dynamics (CFD) has been proposed to guide and support the development of models suitable for accident analysis. The CFD method, on the one hand, is

  5. A Novel Closed-head Model of Mild Traumatic Brain Injury Caused by Primary Overpressure Blast to the Cranium Produces Sustained Emotional Deficits in Mice

    Directory of Open Access Journals (Sweden)

    Scott A Heldt

    2014-01-01

    Full Text Available Emotional disorders are a common outcome from mild traumatic brain injury (TBI in humans, but their pathophysiological basis is poorly understood. We have developed a mouse model of closed-head blast injury using an air pressure wave delivered to a small area on one side of the cranium, which we have used to create mild TBI. We found that 20-psi blasts in 3-month old C57BL/6 male mice yielded no obvious behavioral or histological evidence of brain injury, while 25-40 psi blasts produced transient anxiety in an open field arena but little histological evidence of brain damage. By contrast, 50-60 psi blasts resulted in anxiety-like behavior in an open field arena that became more evident with time after blast. In additional behavioral tests conducted 2-8 weeks after blast, 50-60 psi mice also demonstrated increased acoustic startle, perseverance of learned fear, and enhanced contextual fear, as well as depression-like behavior and diminished prepulse inhibition. We found no evident cerebral pathology, however, and only scattered axonal degeneration in brain sections from 50-60 psi mice 3-8 weeks after blast. Thus, the TBI caused by single 50-60 psi blasts in mice exhibits the minimal neuronal loss coupled to diffuse axonal injury characteristic of human mild TBI. A reduction in the abundance of a subpopulation of excitatory projection neurons in basolateral amygdala enriched in Thy1 was, however, observed. The reported link of this neuronal population to fear suppression suggests their damage by mild TBI may contribute to the heightened anxiety and fearfulness observed after blast in our mice. Our overpressure air blast model of concussion in mice will enable further studies of the mechanisms underlying the diverse emotional deficits seen after mild TBI.

  6. Normal tissue complication probability model parameter estimation for xerostomia in head and neck cancer patients based on scintigraphy and quality of life assessments

    Directory of Open Access Journals (Sweden)

    Lee Tsair-Fwu

    2012-12-01

    Full Text Available Abstract Background With advances in modern radiotherapy (RT, many patients with head and neck (HN cancer can be effectively cured. However, xerostomia is a common complication in patients after RT for HN cancer. The purpose of this study was to use the Lyman–Kutcher–Burman (LKB model to derive parameters for the normal tissue complication probability (NTCP for xerostomia based on scintigraphy assessments and quality of life (QoL questionnaires. We performed validation tests of the Quantitative Analysis of Normal Tissue Effects in the Clinic (QUANTEC guidelines against prospectively collected QoL and salivary scintigraphic data. Methods Thirty-one patients with HN cancer were enrolled. Salivary excretion factors (SEFs measured by scintigraphy and QoL data from self-reported questionnaires were used for NTCP modeling to describe the incidence of grade 3+ xerostomia. The NTCP parameters estimated from the QoL and SEF datasets were compared. Model performance was assessed using Pearson’s chi-squared test, Nagelkerke’s R2, the area under the receiver operating characteristic curve, and the Hosmer–Lemeshow test. The negative predictive value (NPV was checked for the rate of correctly predicting the lack of incidence. Pearson’s chi-squared test was used to test the goodness of fit and association. Results Using the LKB NTCP model and assuming n=1, the dose for uniform irradiation of the whole or partial volume of the parotid gland that results in 50% probability of a complication (TD50 and the slope of the dose–response curve (m were determined from the QoL and SEF datasets, respectively. The NTCP-fitted parameters for local disease were TD50=43.6 Gy and m=0.18 with the SEF data, and TD50=44.1 Gy and m=0.11 with the QoL data. The rate of grade 3+ xerostomia for treatment plans meeting the QUANTEC guidelines was specifically predicted, with a NPV of 100%, using either the QoL or SEF dataset. Conclusions Our study shows the agreement

  7. Normal tissue complication probability model parameter estimation for xerostomia in head and neck cancer patients based on scintigraphy and quality of life assessments

    International Nuclear Information System (INIS)

    Lee, Tsair-Fwu; Chao, Pei-Ju; Wang, Hung-Yu; Hsu, Hsuan-Chih; Chang, PaoShu; Chen, Wen-Cheng

    2012-01-01

    With advances in modern radiotherapy (RT), many patients with head and neck (HN) cancer can be effectively cured. However, xerostomia is a common complication in patients after RT for HN cancer. The purpose of this study was to use the Lyman–Kutcher–Burman (LKB) model to derive parameters for the normal tissue complication probability (NTCP) for xerostomia based on scintigraphy assessments and quality of life (QoL) questionnaires. We performed validation tests of the Quantitative Analysis of Normal Tissue Effects in the Clinic (QUANTEC) guidelines against prospectively collected QoL and salivary scintigraphic data. Thirty-one patients with HN cancer were enrolled. Salivary excretion factors (SEFs) measured by scintigraphy and QoL data from self-reported questionnaires were used for NTCP modeling to describe the incidence of grade 3 + xerostomia. The NTCP parameters estimated from the QoL and SEF datasets were compared. Model performance was assessed using Pearson’s chi-squared test, Nagelkerke’s R 2 , the area under the receiver operating characteristic curve, and the Hosmer–Lemeshow test. The negative predictive value (NPV) was checked for the rate of correctly predicting the lack of incidence. Pearson’s chi-squared test was used to test the goodness of fit and association. Using the LKB NTCP model and assuming n=1, the dose for uniform irradiation of the whole or partial volume of the parotid gland that results in 50% probability of a complication (TD 50 ) and the slope of the dose–response curve (m) were determined from the QoL and SEF datasets, respectively. The NTCP-fitted parameters for local disease were TD 50 =43.6 Gy and m=0.18 with the SEF data, and TD 50 =44.1 Gy and m=0.11 with the QoL data. The rate of grade 3 + xerostomia for treatment plans meeting the QUANTEC guidelines was specifically predicted, with a NPV of 100%, using either the QoL or SEF dataset. Our study shows the agreement between the NTCP parameter modeling based on SEF and

  8. Normal tissue complication probability model parameter estimation for xerostomia in head and neck cancer patients based on scintigraphy and quality of life assessments

    Science.gov (United States)

    2012-01-01

    Background With advances in modern radiotherapy (RT), many patients with head and neck (HN) cancer can be effectively cured. However, xerostomia is a common complication in patients after RT for HN cancer. The purpose of this study was to use the Lyman–Kutcher–Burman (LKB) model to derive parameters for the normal tissue complication probability (NTCP) for xerostomia based on scintigraphy assessments and quality of life (QoL) questionnaires. We performed validation tests of the Quantitative Analysis of Normal Tissue Effects in the Clinic (QUANTEC) guidelines against prospectively collected QoL and salivary scintigraphic data. Methods Thirty-one patients with HN cancer were enrolled. Salivary excretion factors (SEFs) measured by scintigraphy and QoL data from self-reported questionnaires were used for NTCP modeling to describe the incidence of grade 3+ xerostomia. The NTCP parameters estimated from the QoL and SEF datasets were compared. Model performance was assessed using Pearson’s chi-squared test, Nagelkerke’s R2, the area under the receiver operating characteristic curve, and the Hosmer–Lemeshow test. The negative predictive value (NPV) was checked for the rate of correctly predicting the lack of incidence. Pearson’s chi-squared test was used to test the goodness of fit and association. Results Using the LKB NTCP model and assuming n=1, the dose for uniform irradiation of the whole or partial volume of the parotid gland that results in 50% probability of a complication (TD50) and the slope of the dose–response curve (m) were determined from the QoL and SEF datasets, respectively. The NTCP-fitted parameters for local disease were TD50=43.6 Gy and m=0.18 with the SEF data, and TD50=44.1 Gy and m=0.11 with the QoL data. The rate of grade 3+ xerostomia for treatment plans meeting the QUANTEC guidelines was specifically predicted, with a NPV of 100%, using either the QoL or SEF dataset. Conclusions Our study shows the agreement between the NTCP

  9. Using Multivariate Regression Model with Least Absolute Shrinkage and Selection Operator (LASSO) to Predict the Incidence of Xerostomia after Intensity-Modulated Radiotherapy for Head and Neck Cancer

    Science.gov (United States)

    Ting, Hui-Min; Chang, Liyun; Huang, Yu-Jie; Wu, Jia-Ming; Wang, Hung-Yu; Horng, Mong-Fong; Chang, Chun-Ming; Lan, Jen-Hong; Huang, Ya-Yu; Fang, Fu-Min; Leung, Stephen Wan

    2014-01-01

    Purpose The aim of this study was to develop a multivariate logistic regression model with least absolute shrinkage and selection operator (LASSO) to make valid predictions about the incidence of moderate-to-severe patient-rated xerostomia among head and neck cancer (HNC) patients treated with IMRT. Methods and Materials Quality of life questionnaire datasets from 206 patients with HNC were analyzed. The European Organization for Research and Treatment of Cancer QLQ-H&N35 and QLQ-C30 questionnaires were used as the endpoint evaluation. The primary endpoint (grade 3+ xerostomia) was defined as moderate-to-severe xerostomia at 3 (XER3m) and 12 months (XER12m) after the completion of IMRT. Normal tissue complication probability (NTCP) models were developed. The optimal and suboptimal numbers of prognostic factors for a multivariate logistic regression model were determined using the LASSO with bootstrapping technique. Statistical analysis was performed using the scaled Brier score, Nagelkerke R2, chi-squared test, Omnibus, Hosmer-Lemeshow test, and the AUC. Results Eight prognostic factors were selected by LASSO for the 3-month time point: Dmean-c, Dmean-i, age, financial status, T stage, AJCC stage, smoking, and education. Nine prognostic factors were selected for the 12-month time point: Dmean-i, education, Dmean-c, smoking, T stage, baseline xerostomia, alcohol abuse, family history, and node classification. In the selection of the suboptimal number of prognostic factors by LASSO, three suboptimal prognostic factors were fine-tuned by Hosmer-Lemeshow test and AUC, i.e., Dmean-c, Dmean-i, and age for the 3-month time point. Five suboptimal prognostic factors were also selected for the 12-month time point, i.e., Dmean-i, education, Dmean-c, smoking, and T stage. The overall performance for both time points of the NTCP model in terms of scaled Brier score, Omnibus, and Nagelkerke R2 was satisfactory and corresponded well with the expected values. Conclusions

  10. Incidence study of head blows and concussions in competition taekwondo.

    Science.gov (United States)

    Koh, Jae O; Cassidy, J David

    2004-03-01

    To examine the incidence of head blows and concussions in competition taekwondo. Incidence cohort design. Taekwondo tournament in 2001, in South Korea. A total of 2328 competitors (female, 676; male, 1652; age, 11-19 years) from 424 schools participated in the tournament. All recipients of head blows were interviewed immediately after the match. All matches were recorded on videotape. Head blow and concussion rates were calculated. Also, factors associated with head blows and concussions were analyzed. The incidence of head blows and concussions was 226 and 50 per 1000 athlete exposures, respectively. Only 17% of competitors reported that they had had a concussion in the last 12 months. A multinomial logistic model showed that head blows and concussions were associated with young age and a lack of blocking skills. The incidence of head blows and concussions is high in competition taekwondo. Promoting blocking skills to prevent head blows could decrease concussions in taekwondo.

  11. Visual perception of axes of head rotation

    Directory of Open Access Journals (Sweden)

    David Mattijs Arnoldussen

    2013-02-01

    Full Text Available Registration of ego-motion is important to accurately navigate through space. Movements of the head and eye relative to space are registered through the vestibular system and optical flow, respectively. Here, we address three questions concerning the visual registration of self-rotation. 1. Eye-in-head movements provide a link between the motion signals received by sensors in the moving eye and sensors in the moving head. How are these signals combined into an ego-rotation percept? We combined optic flow of simulated forward and rotational motion of the eye with different levels of eye-in-head rotation for a stationary head. We dissociated simulated gaze rotation and head rotation by different levels of eye-in-head pursuit.We found that perceived rotation matches simulated head- not gaze-rotation. This rejects a model for perceived self-rotation that relies on the rotation of the gaze line. Rather, eye-in-head signals serve to transform the optic flow’s rotation information, that specifies rotation of the scene relative to the eye, into a rotation relative to the head. This suggests that transformed visual self-rotation signals may combine with vestibular signals.2. Do transformed visual self-rotation signals reflect the arrangement of the semicircular canals (SCC? Previously, we found sub-regions within MST and V6+ that respond to the speed of the simulated head rotation. Here, we re-analyzed those BOLD signals for the presence of a spatial dissociation related to the axes of visually simulated head rotation, such as have been found in sub-cortical regions of various animals. Contrary, we found a rather uniform BOLD response to simulated rotation along the three SCC axes.3. We investigated if subject’s sensitivity to the direction of the head rotation axis shows SCC axes specifcity. We found that sensitivity to head rotation is rather uniformly distributed, suggesting that in human cortex, visuo-vestibular integration is not arranged into

  12. Visual perception of axes of head rotation

    Science.gov (United States)

    Arnoldussen, D. M.; Goossens, J.; van den Berg, A. V.

    2013-01-01

    Registration of ego-motion is important to accurately navigate through space. Movements of the head and eye relative to space are registered through the vestibular system and optical flow, respectively. Here, we address three questions concerning the visual registration of self-rotation. (1) Eye-in-head movements provide a link between the motion signals received by sensors in the moving eye and sensors in the moving head. How are these signals combined into an ego-rotation percept? We combined optic flow of simulated forward and rotational motion of the eye with different levels of eye-in-head rotation for a stationary head. We dissociated simulated gaze rotation and head rotation by different levels of eye-in-head pursuit. We found that perceived rotation matches simulated head- not gaze-rotation. This rejects a model for perceived self-rotation that relies on the rotation of the gaze line. Rather, eye-in-head signals serve to transform the optic flow's rotation information, that specifies rotation of the scene relative to the eye, into a rotation relative to the head. This suggests that transformed visual self-rotation signals may combine with vestibular signals. (2) Do transformed visual self-rotation signals reflect the arrangement of the semi-circular canals (SCC)? Previously, we found sub-regions within MST and V6+ that respond to the speed of the simulated head rotation. Here, we re-analyzed those Blood oxygenated level-dependent (BOLD) signals for the presence of a spatial dissociation related to the axes of visually simulated head rotation, such as have been found in sub-cortical regions of various animals. Contrary, we found a rather uniform BOLD response to simulated rotation along the three SCC axes. (3) We investigated if subject's sensitivity to the direction of the head rotation axis shows SCC axes specifcity. We found that sensitivity to head rotation is rather uniformly distributed, suggesting that in human cortex, visuo-vestibular integration is

  13. Head and Neck Cancer Treatment

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Head and Neck Cancer Treatment Head and neck cancer ... there any new developments in treating my disease? Head and neck cancer overview The way a particular ...

  14. American Head and Neck Society

    Science.gov (United States)

    American Head & Neck Society Mission Statement: Advance Education, Research, and Quality of Care for the head and neck oncology patient. American Head & Neck Society | AHNS The mission of the AHNS is to ...

  15. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... MRI of the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is a noninvasive ... of page What are some common uses of the procedure? MR imaging of the head is performed ...

  16. Head injuries in sport.

    Science.gov (United States)

    Cantu, R C

    1996-12-01

    Injuries to the head and neck are the most frequent catastrophic sports injury, and head injuries are the most common direct athletic cause of death. Although direct compressive forces may injure the brain, neural tissue is particularly susceptible to injury from shearing stresses, which are most likely to occur when rotational forces are applied to the head. The most common athletic head injury is concussion, which may very widely in severity. Intracranial haemorrhage is the leading cause of head injury death in sports, making rapid initial assessment and appropriate follow up mandatory after a head injury. Diffuse cerebral swelling is another serious condition that may be found in the child or adolescent athlete, and the second impact syndrome is a major concern in adult athletes. Many head injuries in athletes are the result of improper playing techniques and can be reduced by teaching proper skills and enforcing safety promoting rules. Improved conditioning (particularly of the neck), protective headgear, and careful medical supervision of athletes will also minimise this type of injury.

  17. Analytical modelling of soccer heading

    Indian Academy of Sciences (India)

    . It was found that soccer players had scored poorly in the tests compared with the participants who did not play soccer (Matser et al 1999; Witol & Webbe 2003). Frequent headers were also found to have obtained even lower scores compared ...

  18. Femoral head avascular necrosis

    International Nuclear Information System (INIS)

    Chrysikopoulos, H.; Sartoris, D.J.; Resnick, D.L.; Ashburn, W.; Pretorius, T.

    1988-01-01

    MR imaging has been shown to be more sensitive and specific than planar scintigraphy for avascular necrosis (AVN) of the femoral head. However, experience with single photon emission CT (SPECT) is limited. The authors retrospectively compared 1.5-T MR imaging with SPECT in 14 patients with suspected femoral head AVN. Agreement between MR imaging and SPECT was present in 24 femurs, 14 normal and ten with AVN. MR imaging showed changes of AVN in the remaining four femoral heads. Of these, one was normal and the other three inconclusive for AVN by SPECT. The authors conclude that MR imaging is superior to SPECT for the evaluation of AVN of the hip

  19. Evaluation of a new concept of immune-enhancing diet in a model of head-injured rat with infectious complications: A proof of concept study.

    Science.gov (United States)

    Charrueau, Christine; Moinard, Christophe; Brinkmann, Saskia; Choisy, Caroline; Butel, Marie-José; Bureau, Michel-Francis; Le Plénier, Servane; Brignole-Baudouin, Françoise; Neveux, Nathalie; Cynober, Luc; De Bandt, Jean-Pascal

    2016-12-01

    Immune-enhancing diet (IED) utilization in critically ill septic patients is still debated. A new concept of IED has been proposed combining extra glutamine sequentially with either antioxidants or other amino acids, in order to match patient requirements according to their response to injury. We evaluated whether this new IED elicits a more favorable response to stress when compared with two existing IEDs both enriched in arginine but with different levels of anti-oxidants, in a validated rat model combining head injury (HI) and infectious complications. Forty-eight HI rats were randomized into four groups (n = 11-13 per group) to receive, for 4 days, standard enteral nutrition (S), one of the two existing IEDs (IED1, IED2), or the new IED (IED3; providing glutamine and antioxidants for two days and glutamine and specific amino acids for two days). Two days after HI, the rats received an enteral bolus of luminescent Escherichia coli Xen14 to induce infection, and bacterial dissemination was evaluated. Body weight (BW) was recorded daily. Four days after HI, animals were euthanized; blood was sampled; organs were weighed; cumulated nitrogen balance (CNB) and nitrogen efficiency were determined. IED3 was more efficient than IED1 and IED2 in improving BW recovery from D3 (D3 vs. D1, p anti-oxidants and glutamine may be better suited to meeting nutritional requirements in severe catabolic states. Copyright © 2016 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  20. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... used to detect: bleeding, brain injury and skull fractures in patients with head injuries. bleeding caused by ... be asked to remove hearing aids and removable dental work. Women will be asked to remove bras ...

  1. TCGA head Neck

    Science.gov (United States)

    Investigators with The Cancer Genome Atlas (TCGA) Research Network have discovered genomic differences – with potentially important clinical implications – in head and neck cancers caused by infection with the human papillomavirus (HPV).

  2. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... microphone. top of page How does the procedure work? In many ways CT scanning works very much ... head CT scanning. Manufacturers of intravenous contrast indicate mothers should not breastfeed their babies for 24-48 ...

  3. Head Start Impact Study

    Data.gov (United States)

    U.S. Department of Health & Human Services — Nationally representative, longitudinal information from an evaluation where children were randomly assigned to Head Start or community services as usual;direct...

  4. Early Head Start Evaluation

    Data.gov (United States)

    U.S. Department of Health & Human Services — Longitudinal information from an evaluation where children were randomly assigned to Early Head Start or community services as usual;direct assessments and...

  5. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... assess head injuries, severe headaches, dizziness, and other symptoms of aneurysm, bleeding, stroke and brain tumors. It ... within the brain shortly after a patient exhibits symptoms of a stroke. a stroke, especially with a ...

  6. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... Survey Do you have a personal story about radiology? Share your patient story here Images × Image Gallery ... Pregnancy Head and Neck Cancer X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety Images related to ...

  7. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... special x-ray equipment to help assess head injuries, severe headaches, dizziness, and other symptoms of aneurysm, ... cancer. In emergency cases, it can reveal internal injuries and bleeding quickly enough to help save lives. ...

  8. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... rays). top of page What are some common uses of the procedure? CT scanning of the head ... special computer program processes this large volume of data to create two-dimensional cross-sectional images of ...

  9. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... scans in children should always be done with low-dose technique. top of page What are the ... page Additional Information and Resources RTAnswers.org Radiation Therapy for Brain Tumors Radiation Therapy for Head and ...

  10. Overview of Head Injuries

    Science.gov (United States)

    ... kept in the emergency department or hospital for observation. Children who have had a minor head injury ... penetrating trauma (such as a knife or gunshot wound). Injuries may range from relatively small hematomas (collections ...

  11. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... rays). top of page What are some common uses of the procedure? CT scanning of the head ... is done because a potential abnormality needs further evaluation with additional views or a special imaging technique. ...

  12. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... headaches, dizziness, and other symptoms of aneurysm, bleeding, stroke and brain tumors. It also helps your doctor ... scanning provides more detailed information on head injuries, stroke , brain tumors and other brain diseases than regular ...

  13. The relevance of MRI for patient modeling in head and neck hyperthermia treatment planning: A comparison of CT and CT-MRI based tissue segmentation on simulated temperature

    Energy Technology Data Exchange (ETDEWEB)

    Verhaart, René F., E-mail: r.f.verhaart@erasmusmc.nl; Paulides, Margarethus M. [Hyperthermia Unit, Department of Radiation Oncology, Erasmus MC - Cancer Institute, Groene Hilledijk 301, Rotterdam 3008 AE (Netherlands); Fortunati, Valerio; Walsum, Theo van; Veenland, Jifke F. [Biomedical Imaging Group of Rotterdam, Department of Medical Informatics and Radiology, Erasmus MC, Dr. Molewaterplein 50/60, Rotterdam 3015 GE (Netherlands); Verduijn, Gerda M. [Department of Radiation Oncology, Erasmus MC - Cancer Institute, Groene Hilledijk 301, Rotterdam 3008 AE (Netherlands); Lugt, Aad van der [Department of Radiology, Erasmus MC, Dr. Molewaterplein 50/60, Rotterdam 3015 GE (Netherlands)

    2014-12-15

    Purpose: In current clinical practice, head and neck (H and N) hyperthermia treatment planning (HTP) is solely based on computed tomography (CT) images. Magnetic resonance imaging (MRI) provides superior soft-tissue contrast over CT. The purpose of the authors’ study is to investigate the relevance of using MRI in addition to CT for patient modeling in H and N HTP. Methods: CT and MRI scans were acquired for 11 patients in an immobilization mask. Three observers manually segmented on CT, MRI T1 weighted (MRI-T1w), and MRI T2 weighted (MRI-T2w) images the following thermo-sensitive tissues: cerebrum, cerebellum, brainstem, myelum, sclera, lens, vitreous humor, and the optical nerve. For these tissues that are used for patient modeling in H and N HTP, the interobserver variation of manual tissue segmentation in CT and MRI was quantified with the mean surface distance (MSD). Next, the authors compared the impact of CT and CT and MRI based patient models on the predicted temperatures. For each tissue, the modality was selected that led to the lowest observer variation and inserted this in the combined CT and MRI based patient model (CT and MRI), after a deformable image registration. In addition, a patient model with a detailed segmentation of brain tissues (including white matter, gray matter, and cerebrospinal fluid) was created (CT and MRI{sub db}). To quantify the relevance of MRI based segmentation for H and N HTP, the authors compared the predicted maximum temperatures in the segmented tissues (T{sub max}) and the corresponding specific absorption rate (SAR) of the patient models based on (1) CT, (2) CT and MRI, and (3) CT and MRI{sub db}. Results: In MRI, a similar or reduced interobserver variation was found compared to CT (maximum of median MSD in CT: 0.93 mm, MRI-T1w: 0.72 mm, MRI-T2w: 0.66 mm). Only for the optical nerve the interobserver variation is significantly lower in CT compared to MRI (median MSD in CT: 0.58 mm, MRI-T1w: 1.27 mm, MRI-T2w: 1.40 mm

  14. Mathematical Model of Movement of the Observation and Tracking Head of an Unmanned Aerial Vehicle Performing Ground Target Search and Tracking

    Directory of Open Access Journals (Sweden)

    Izabela Krzysztofik

    2014-01-01

    Full Text Available The paper presents the kinematics of mutual movement of an unmanned aerial vehicle (UAV and a ground target. The controlled observation and tracking head (OTH is a device responsible for observing the ground, searching for a ground target, and tracking it. The preprogrammed movement of the UAV on the circle with the simultaneous movement of the head axis on Archimedes’ spiral during searching for a ground target, both fixed (bunkers, rocket missiles launching positions, etc. and movable (tanks, infantry fighting vehicles, etc., is considered. Dynamics of OTH during the performance of the above mentioned activities is examined. Some research results are presented in a graphical form.

  15. High-Content Screening Comparison of Cancer Drug Accumulation and Distribution in Two-Dimensional and Three-Dimensional Culture Models of Head and Neck Cancer.

    Science.gov (United States)

    Shan, Feng; Close, David A; Camarco, Daniel P; Johnston, Paul A

    2018-01-01

    High cancer drug development attrition rates have provoked considerable debate about whether the two-dimensional tumor growth inhibition high-throughput screening assays used in pre-clinical lead discovery adequately reflect solid tumor complexity. We used automated high-content screening image acquisition and analysis methods to compare fluorescent drug uptake, accumulation, and distribution in Cal33 and FaDu head and neck cancer (HNC) monolayer and multicellular tumor spheroid (MCTS) models. Ellipticine, idarubicin, daunorubicin, and doxorubicin were studied because of their fluorescent properties and broad anti-tumor activities. HNC MCTSs were generated in 384-well ultra-low attachment plates where compound exposure, image acquisition, and analysis could be performed in situ. Fluorescent drug accumulation in Cal33 monolayer and MCTS cultures was linear with respect to concentration, and appeared to achieve steady-state levels within 10-15 min of drug exposure, which were maintained through 30-45 min. Drug accumulation in monolayers was independent of cell number and/or density, and every cell achieved uniform drug concentrations. In MCTSs, however, drug accumulation increased as the number of cells and sizes of the MCTSs became bigger. Drugs exhibited restricted penetration and distribution gradients, accumulating preferentially in cells in the outer layers of MCTSs relative to those in the inner cores. Cal33 monolayers were 6-, 20-, 10-, and 16-fold more sensitive than MCTSs to growth inhibition by ellipticine, idarubicin, daunorubicin, and doxorubicin, respectively. In Cal33 MCTSs exposed to ellipticine or doxorubicin for 24 h, MCTSs were smaller and although they still exhibited drug penetration and distribution gradients, the fluorescent intensity difference between outer and inner cells was reduced. After a 24 h exposure, both drugs had penetrated throughout FaDu MCTSs, consistent with drug-induced death of peripheral cell layers enhancing drug

  16. The importance of rotational kinematics in pedestrian head to windshield impacts

    NARCIS (Netherlands)

    Mordaka, J.; Kleiven, S.; Schijndel-de Nooij, M. van; Lange, R. de; Casanova, L.J.G.; Carter, E.L.; Holst, H. von

    2007-01-01

    The objective of the present study was to analyze the effect of angular kinematics on head injury in pedestrian head-to-windshield impacts. Three cases of pedestrian head impacts were simulated with FE head and windshield models. The initial impact conditions were obtained from pedestrian accident

  17. A Laboratory Based Investigation of a New Elastic Toothbrush Head

    OpenAIRE

    Lorenzo Mazza; Maria Rosaria Gatto; Giuseppe Monaco; Gian Andrea Pelliccioni

    2014-01-01

    Purpose. To demonstrate the noninferiority of a new toothbrush head with retractile bristles compared to traditional toothbrush heads on dental models. Methods. The new toothbrush head, mounted on manual and electrical handles, presents retractile bristle groups that can singularly retract over its entire length and offer calibrated resistance. Fourteen gypsum models of dental arches, twelve with and two without anatomical impairments, were spread with a “plaque simulator.” Each arch was brus...

  18. Modelação da perda de carga na filtração direta ascendente em meio granular de areia grossa e pedregulho Modeling of the head loss in up flow coarse sand and gravel direct filtration

    Directory of Open Access Journals (Sweden)

    Alexandre Botari

    2009-06-01

    Full Text Available Compreender e quantificar os mecanismos relacionados à perda de carga e à remoção de partículas em um meio filtrante granular é de importância fundamental para o estudo do processo da filtração. Este trabalho apresenta o desenvolvimento dos modelos de perda de carga na filtração em meios porosos e a proposição da modelação matemática semiempírica da perda de carga para meios filtrantes limpos e do desenvolvimento do perfil de perda de carga ao longo do tempo de filtração a partir da equação de Ergun. Objetivou-se a determinação dos valores das constantes da equação de Ergun para meio granular de areia grossa e pedregulho. Alguns exemplos de aplicação dessa modelação matemática são também apresentados e discutidos pelos autores com base em dados experimentais obtidos em uma estação piloto de dupla filtração.To understand and to quantify the head loss due to the particles removal in a porous medium has primary importance to filtration process study. This paper presents the development of the models of head loss used in the filtration in porous media and proposes a mathematical semi-empiric model for head loss in clean beds and head loss increasing profile during the filtration run length, by means of the Ergun equation. The goal was the determination of Ergun’s equation coefficients for granular material constituted of coarse sand and gravel. Examples of application of these mathematical modeling are also presented and discussed by the authors based on experimental data obtained in a double filtration pilot plant.

  19. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head uses a powerful ... Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is a noninvasive medical test that ...

  20. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head ... limitations of MRI of the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is ...

  1. Learning toward practical head pose estimation

    Science.gov (United States)

    Sang, Gaoli; He, Feixiang; Zhu, Rong; Xuan, Shibin

    2017-08-01

    Head pose is useful information for many face-related tasks, such as face recognition, behavior analysis, human-computer interfaces, etc. Existing head pose estimation methods usually assume that the face images have been well aligned or that sufficient and precise training data are available. In practical applications, however, these assumptions are very likely to be invalid. This paper first investigates the impact of the failure of these assumptions, i.e., misalignment of face images, uncertainty and undersampling of training data, on head pose estimation accuracy of state-of-the-art methods. A learning-based approach is then designed to enhance the robustness of head pose estimation to these factors. To cope with misalignment, instead of using hand-crafted features, it seeks suitable features by learning from a set of training data with a deep convolutional neural network (DCNN), such that the training data can be best classified into the correct head pose categories. To handle uncertainty and undersampling, it employs multivariate labeling distributions (MLDs) with dense sampling intervals to represent the head pose attributes of face images. The correlation between the features and the dense MLD representations of face images is approximated by a maximum entropy model, whose parameters are optimized on the given training data. To estimate the head pose of a face image, its MLD representation is first computed according to the model based on the features extracted from the image by the trained DCNN, and its head pose is then assumed to be the one corresponding to the peak in its MLD. Evaluation experiments on the Pointing'04, FacePix, Multi-PIE, and CASIA-PEAL databases prove the effectiveness and efficiency of the proposed method.

  2. An integrated model-driven method for in-treatment upper airway motion tracking using cine MRI in head and neck radiation therapy.

    Science.gov (United States)

    Li, Hua; Chen, Hsin-Chen; Dolly, Steven; Li, Harold; Fischer-Valuck, Benjamin; Victoria, James; Dempsey, James; Ruan, Su; Anastasio, Mark; Mazur, Thomas; Gach, Michael; Kashani, Rojano; Green, Olga; Rodriguez, Vivian; Gay, Hiram; Thorstad, Wade; Mutic, Sasa

    2016-08-01

    For the first time, MRI-guided radiation therapy systems can acquire cine images to dynamically monitor in-treatment internal organ motion. However, the complex head and neck (H&N) structures and low-contrast/resolution of on-board cine MRI images make automatic motion tracking a very challenging task. In this study, the authors proposed an integrated model-driven method to automatically track the in-treatment motion of the H&N upper airway, a complex and highly deformable region wherein internal motion often occurs in an either voluntary or involuntary manner, from cine MRI images for the analysis of H&N motion patterns. Considering the complex H&N structures and ensuring automatic and robust upper airway motion tracking, the authors firstly built a set of linked statistical shapes (including face, face-jaw, and face-jaw-palate) using principal component analysis from clinically approved contours delineated on a set of training data. The linked statistical shapes integrate explicit landmarks and implicit shape representation. Then, a hierarchical model-fitting algorithm was developed to align the linked shapes on the first image frame of a to-be-tracked cine sequence and to localize the upper airway region. Finally, a multifeature level set contour propagation scheme was performed to identify the upper airway shape change, frame-by-frame, on the entire image sequence. The multifeature fitting energy, including the information of intensity variations, edge saliency, curve geometry, and temporal shape continuity, was minimized to capture the details of moving airway boundaries. Sagittal cine MR image sequences acquired from three H&N cancer patients were utilized to demonstrate the performance of the proposed motion tracking method. The tracking accuracy was validated by comparing the results to the average of two manual delineations in 50 randomly selected cine image frames from each patient. The resulting average dice similarity coefficient (93.28%  ±  1

  3. Pulsed Radiation Therapy With Concurrent Cisplatin Results in Superior Tumor Growth Delay in a Head and Neck Squamous Cell Carcinoma Murine Model

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Kurt; Krueger, Sarah A.; Kane, Jonathan L.; Wilson, Thomas G.; Hanna, Alaa; Dabjan, Mohamad; Hege, Katie M.; Wilson, George D.; Grills, Inga; Marples, Brian, E-mail: brian.marples@beaumont.edu

    2016-09-01

    Purpose: To assess the efficacy of 3-week schedules of low-dose pulsed radiation treatment (PRT) and standard radiation therapy (SRT), with concurrent cisplatin (CDDP) in a head and neck squamous cell carcinoma xenograft model. Methods and Materials: Subcutaneous UT-SCC-14 tumors were established in athymic NIH III HO female mice. A total of 30 Gy was administered as 2 Gy/d, 5 d/wk for 3 weeks, either by PRT (10 × 0.2 Gy/d, with a 3-minute break between each 0.2-Gy dose) or SRT (2 Gy/d, uninterrupted delivery) in combination with concurrent 2 mg/kg CDDP 3 times per week in the final 2 weeks of radiation therapy. Treatment-induced growth delays were defined from twice-weekly tumor volume measurements. Tumor hypoxia was assessed by {sup 18}F-fluoromisonidazole positron emission tomography imaging, and calculated maximum standardized uptake values compared with tumor histology. Tumor vessel density and hypoxia were measured by quantitative immunohistochemistry. Normal tissues effects were evaluated in gut and skin. Results: Untreated tumors grew to 1000 mm{sup 3} in 25.4 days (±1.2), compared with delays of 62.3 days (±3.5) for SRT + CDDP and 80.2 days (±5.0) for PRT + CDDP. Time to reach 2× pretreatment volume ranged from 8.2 days (±1.8) for untreated tumors to 67.1 days (±4.7) after PRT + CDDP. Significant differences in tumor growth delay were observed for SRT versus SRT + CDDP (P=.04), PRT versus PRT + CDDP (P=.035), and SRT + CDDP versus PRT + CDDP (P=.033), and for survival between PRT versus PRT + CDDP (P=.017) and SRT + CDDP versus PRT + CDDP (P=.008). Differences in tumor hypoxia were evident by {sup 18}F-fluoromisonidazole positron emission tomography imaging between SRT and PRT (P=.025), although not with concurrent CDDP. Tumor vessel density differed between SRT + CDDP and PRT + CDDP (P=.011). No differences in normal tissue parameters were seen. Conclusions: Concurrent CDDP was more effective in combination PRT than SRT at

  4. Detecting Intracranial Hemorrhage Using Automatic Tube Current Modulation With Advanced Modeled Iterative Reconstruction in Unenhanced Head Single- and Dual-Energy Dual-Source CT.

    Science.gov (United States)

    Scholtz, Jan-Erik; Wichmann, Julian L; Bennett, Dennis W; Leithner, Doris; Bauer, Ralf W; Vogl, Thomas J; Bodelle, Boris

    2017-05-01

    The purpose of our study was to determine diagnostic accuracy, image quality, and radiation dose of low-dose single- and dual-energy unenhanced third-generation dual-source head CT for detection of intracranial hemorrhage (ICH). A total of 123 patients with suspected ICH were examined using a dual-source 192-MDCT scanner. Standard-dose 120-kVp single-energy CT (SECT; n = 36) and 80-kVp and 150-kVp dual-energy CT (DECT; n = 30) images were compared with low-dose SECT (n = 32) and DECT (n = 25) images obtained using automated tube current modulation (ATCM). Advanced modeled iterative reconstruction (ADMIRE) was used for all protocols. Detection of ICH was performed by three readers who were blinded to the image acquisition parameters of each image series. Image quality was assessed both quantitatively and qualitatively. Interobserver agreement was calculated using the Fleiss kappa. Radiation dose was measured as dose-length product (DLP). Detection of ICH was excellent (sensitivity, 94.9-100%; specificity, 94.7-100%) in all protocols (p = 1.00) with perfect interobserver agreement (0.83-0.96). Qualitative ratings showed significantly better ratings for both standard-dose protocols regarding gray matter-to-white matter contrast (p ≤ 0.014), whereas highest gray matter-to-white matter contrast-to-noise ratio was observed with low-dose DECT images (p ≥ 0.057). The lowest posterior fossa artifact index was measured for standard-dose DECT, which showed significantly lower values compared with low-dose protocols (p ≤ 0.034). Delineation of ventricular margins and sharpness of subarachnoidal spaces were rated excellent in all protocols (p ≥ 0.096). Low-dose techniques lowered radiation dose by 26% for SECT images (DLP, 575.0 ± 72.3 mGy · cm vs 771.5 ± 146.8 mGy · cm; p dual-source CT while allowing significant radiation dose reduction.

  5. Head trauma in China.

    Science.gov (United States)

    Jiang, Ji-Yao

    2013-11-01

    The Chinese Head Trauma Data Bank (CHTDB) has been established, which includes 7,145 hospitalised cases with acute head trauma patients in 47 hospitals. We explored factors that might affect the outcome of acute traumatic brain injury. There was no statistical difference in the mortality rate between male (7.5%) and female (7.2%) patients (P>0.05). The mortality rate in children (65 years) was 7.3%, 7.2% and 9.0%, respectively (P>0.05). The mortality rate of patients with mild (2.7%), moderate (5.0%) and severe (21.8%) head trauma was significantly different (P40 mm Hg was 6.3%, 21.4% and 93.1%, respectively (Phead trauma data bank in China, has one of the largest numbers of cases of any head trauma data bank in the world. Our major findings on mortality may be helpful to neurosurgeons for predicting the outcome of acute head trauma patients. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Head first Ajax

    CERN Document Server

    Riordan, Rebecca M

    2008-01-01

    Ajax is no longer an experimental approach to website development, but the key to building browser-based applications that form the cornerstone of Web 2.0. Head First Ajax gives you an up-to-date perspective that lets you see exactly what you can do -- and has been done -- with Ajax. With it, you get a highly practical, in-depth, and mature view of what is now a mature development approach. Using the unique and highly effective visual format that has turned Head First titles into runaway bestsellers, this book offers a big picture overview to introduce Ajax, and then explores the use of ind

  7. Head First Statistics

    CERN Document Server

    Griffiths, Dawn

    2009-01-01

    Wouldn't it be great if there were a statistics book that made histograms, probability distributions, and chi square analysis more enjoyable than going to the dentist? Head First Statistics brings this typically dry subject to life, teaching you everything you want and need to know about statistics through engaging, interactive, and thought-provoking material, full of puzzles, stories, quizzes, visual aids, and real-world examples. Whether you're a student, a professional, or just curious about statistical analysis, Head First's brain-friendly formula helps you get a firm grasp of statistics

  8. From crash test speed to performance in real world conditions: a conceptual model and its application to underhood clearance in pedestrian head tests.

    Science.gov (United States)

    Searson, Daniel J; Hutchinson, T Paul; Anderson, Robert W G

    2012-10-01

    Current safety testing protocols typically evaluate performance at a single test speed, which may have undesirable side effects if vehicles are optimised to perform at that speed without consideration to performance at other speeds. One way of overcoming this problem is by using an evaluation that incorporates the distribution of speeds that would be encountered in real crashes, the relationship between test speed and test performance, and the relationship between test performance and injury risk. Such an evaluation is presented in this paper and is applied to pedestrian headform testing. The applicable distribution of pedestrian impact speeds was compiled from in-depth crash data. Values of the Head Injury Criterion across the speed distribution were imputed from a single test result, taking into account the potential for 'bottoming out' on harder structures beneath the hood. Two different risk functions were used: skull fracture risk and fatal head injury risk. Eight example test locations were evaluated; each had an underhood clearance such that it would perform worse at higher speeds than suggested by its original test result. When the effect of bottoming out was included in the evaluation, the calculated average injury risk was generally higher than it was if bottoming out was ignored. The average risk of fatal head injury was more affected by the inclusion of bottoming out than the average skull fracture risk. The methodology presented in this paper may be extended to other forms of impact testing, although the input functions may be more difficult to derive for more complex tests.

  9. Recalibration of a ground-water flow model of the Mississippi River Valley alluvial aquifer in Southeastern Arkansas, 1918, with simulations of hydraulic heads caused by projected ground-water withdrawals through 2049

    Science.gov (United States)

    Stanton, Gregory P.; Clark, Brian R.

    2003-01-01

    The Mississippi River Valley alluvial aquifer, encompassing parts of Arkansas, Kentucky, Louisiana, Mississippi, Missouri, and Tennessee supplies an average of 5 billion gallons of water per day. However, withdrawals from the aquifer in recent years have caused considerable drawdown in the hydraulic heads in southeastern Arkansas and other areas. The effects of current ground-water withdrawals and potential future withdrawals on water availability are major concerns of water managers and users as well as the general public. A full understanding of the behavior of the aquifer under various water-use scenarios is critical for the development of viable water-management and alternative source plans. To address these concerns, the U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, Vicksburg District, and the Arkansas Soil and Water Conservation Commission developed and calibrated a ground-water flow model for the Mississippi River valley alluvial aquifer in southeastern Arkansas to simulate hydraulic heads caused by projected ground-water withdrawals. A previously published ground-water flow model for the alluvial aquifer in southeastern Arkansas was updated and recalibrated to reflect more current pumping stresses with additional stress periods added to bring the model forward from 1982 to 1998. The updated model was developed and calibrated with MODFLOW-2000 finite difference numerical modeling and parameter estimation software. The model was calibrated using hydraulic-head data collected during 1972 and 1982 and hydraulic-head measurements made during spring (February to April) of 1992 and 1998. The residuals for 1992 and 1998 have a mean absolute value of 4.74 and 5.45 feet, respectively, and a root mean square error of 5.9 and 6.72 feet, respectively. The effects of projected ground-water withdrawals were simulated through 2049 in three predictive scenarios by adding five additional stress periods of 10 years each. In the three scenarios

  10. Reactor pressure vessel vented head

    Science.gov (United States)

    Sawabe, James K.

    1994-01-11

    A head for closing a nuclear reactor pressure vessel shell includes an arcuate dome having an integral head flange which includes a mating surface for sealingly mating with the shell upon assembly therewith. The head flange includes an internal passage extending therethrough with a first port being disposed on the head mating surface. A vent line includes a proximal end disposed in flow communication with the head internal passage, and a distal end disposed in flow communication with the inside of the dome for channeling a fluid therethrough. The vent line is fixedly joined to the dome and is carried therewith when the head is assembled to and disassembled from the shell.

  11. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Head ...

  12. Silva as the Head

    DEFF Research Database (Denmark)

    Svabo, Connie

    2015-01-01

    The head of the performance design programme is substituted by a sister's academy delegate. this performance situation formed part of a week of semesterstart where the students and professors visited Sister's Academy, Malmø. I participated in the Sister's Academy as visiting researcher and here...

  13. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... assess head injuries, severe headaches, dizziness, and other symptoms of aneurysm, bleeding, stroke and brain tumors. It also helps your doctor to evaluate your face, sinuses, and skull or to plan radiation therapy for brain cancer. In emergency cases, it can ...

  14. Overview of Head Injuries

    Science.gov (United States)

    ... falls, motor vehicle crashes, assaults, and mishaps during sports and recreational activities. People with minor head injuries may have a headache ... feel part of the body Inability to recognize people or the ... vision, or blind spots) Drainage of clear fluid (cerebrospinal fluid) from ...

  15. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... on head injuries, stroke , brain tumors and other brain diseases than regular radiographs (x-rays). top of page ... to obtain a tissue sample ( biopsy ) from the brain. assess aneurysms or ... or any disorder of the heart, kidneys or thyroid gland , or ...

  16. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... full size with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media Radiation Dose in X-Ray and CT Exams Blood Clots CT Perfusion of the Head CT Angiography ( ...

  17. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos ... head injuries, stroke , brain tumors and other brain diseases than regular radiographs (x-rays). top of page ...

  18. Head Lice: Information for Parents

    Science.gov (United States)

    ... Tropical Diseases Laboratory Diagnostic Assistance [DPDx] Parasites Home Head Lice Information for Parents Language: English Español (Spanish) ... Tweet Share Compartir You should examine your child's head, especially behind the ears and at the nape ...

  19. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... are the limitations of MRI of the Head? What is MRI of the Head? Magnetic resonance imaging ( ... brain) in routine clinical practice. top of page What are some common uses of the procedure? MR ...

  20. Head, Neck, and Oral Cancer

    Medline Plus

    Full Text Available ... Pathology Oral, Head and Neck Pathology Close to 49,750 Americans will be diagnosed with oral or ... Pathology Oral, Head and Neck Pathology Close to 49,750 Americans will be diagnosed with oral or ...

  1. Childhood Head and Neck Irradiation

    Science.gov (United States)

    ... Thyroid Association ® www.thyroid.org Childhood Head & Neck Irradiation What is the thyroid gland? The thyroid gland ... Thyroid Association ® www.thyroid.org Childhood Head & Neck Irradiation Thyroid nodules (see Thyroid Nodule brochure) • Thyroid nodules ...

  2. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head uses a powerful magnetic field, radio waves and a computer to produce ...

  3. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... for Brain Tumors Radiation Therapy for Head and Neck Cancer Others : American Stroke Association National Stroke Association ... MRA) Magnetic Resonance, Functional (fMRI) - Brain Head and Neck Cancer Treatment Brain Tumor Treatment Magnetic Resonance Imaging ( ...

  4. Effect of pumping head on solar water pumping system

    International Nuclear Information System (INIS)

    Benghanem, M.; Daffallah, K.O.; Alamri, S.N.; Joraid, A.A.

    2014-01-01

    Highlights: • Pumping head affect the performances of PV water pumping systems. • The best system efficiency has been obtained for a deep head. • System efficiency increases with decreasing pumping head during low solar radiation. • System efficiency increases with increasing solar radiation. • Increasing PV array size increases flow rate and system efficiency. - Abstract: The photovoltaic water pumping systems (PVWPS) is considered as one of the most promising areas in photovoltaic applications. The aim of this work is to determine the effect of pumping head on PVWPS using the optimum PV array configuration, adequate to supply a DC Helical pump with an optimum energy amount, under the outdoor conditions of Madinah site. Four different pumping head have been tested (50 m, 60 m, 70 m and 80 m). The tests have been carried for a different heads, under sunny daylight hours, in a real well at a farm in Madinah site. The best system efficiency has been obtained for the head of 80 m which is recommended for SQF submersible pump for a deep head. Also, the flow rate Q depends basically on two factors: the pumping head H and the global solar irradiation Hg. The model developed should be able to predict the flow rate Q for any head chosen with a best accuracy

  5. Crystal structure of raptor adenovirus 1 fibre head and role of the beta-hairpin in siadenovirus fibre head domains.

    Science.gov (United States)

    Nguyen, Thanh H; Ballmann, Mónika Z; Do, Huyen T; Truong, Hai N; Benkő, Mária; Harrach, Balázs; van Raaij, Mark J

    2016-06-22

    Most adenoviruses recognize their host cells via an interaction of their fibre head domains with a primary receptor. The structural framework of adenovirus fibre heads is conserved between the different adenovirus genera for which crystal structures have been determined (Mastadenovirus, Aviadenovirus, Atadenovirus and Siadenovirus), but genus-specific differences have also been observed. The only known siadenovirus fibre head structure, that of turkey adenovirus 3 (TAdV-3), revealed a twisted beta-sandwich resembling the reovirus fibre head architecture more than that of other adenovirus fibre heads, plus a unique beta-hairpin embracing a neighbouring monomer. The TAdV-3 fibre head was shown to bind sialyllactose. Raptor adenovirus 1 (RAdV-1) fibre head was expressed, crystallized and its structure was solved and refined at 1.5 Å resolution. The structure could be solved by molecular replacement using the TAdV-3 fibre head structure as a search model, despite them sharing a sequence identity of only 19 %. Versions of both the RAdV-1 and TAdV-3 fibre heads with their beta-hairpin arm deleted were prepared and their stabilities were compared with the non-mutated proteins by a thermal unfolding assay. The structure of the RAdV-1 fibre head contains the same twisted ABCJ-GHID beta-sandwich and beta-hairpin arm as the TAdV-3 fibre head. However, while the predicted electro-potential surface charge of the TAdV-3 fibre head is mainly positive, the RAdV-1 fibre head shows positively and negatively charged patches and does not appear to bind sialyllactose. Deletion of the beta-hairpin arm does not affect the structure of the raptor adenovirus 1 fibre head and only affects the stability of the RAdV-1 and TAdV-3 fibre heads slightly. The high-resolution structure of RAdV-1 fibre head is the second known structure of a siadenovirus fibre head domain. The structure shows that the siadenovirus fibre head structure is conserved, but differences in the predicted surface charge

  6. PENGGUNAAN MODEL PEMBELAJARAN NUMBERED HEAD TOGETHER UNTUK MENINGKATKAN HASIL BELAJAR SISWA (Studi Pada Mata Pelajaran PAI Kelas VIII SMP Islam Unggulan Miftahul Ulum Bandar Sribhawono Lampung Timur TP. 2015/2016

    Directory of Open Access Journals (Sweden)

    Nur Kholis

    2017-07-01

    Full Text Available Rendahnya hasil belajar pada mata pelajaran Pendidikan Agama Islam kelas VIII di SMP Islam Unggulan Miftaahul ‘Uluum Bandar Sribhawono terlihat dari 20 siswa yang mengikuti pembelajaran hanya 4 siswa atau 20% siswa yang tuntas belajarnya. Rendahnya hasil belajar ini disebabkan oleh berbagai faktor salah satunya disebabkan model pembelajaran yang digunakan oleh guru tidak sesuai dengan materi yang diajarkan. Penelitian ini bertujuan untuk meningkatkan hasil belajar Pendidikan Agama Islam melalui penerapan model Pembelajaran Kooperatif  tipe Numbered Head Together. Jenis penelitian yang dilakukan adalah Penelitian Tindakan Kelas (PTK dengan Subjek penelitian berjumlah 20 orang. Tehnik pengumpulan data menggunakan tes dan dokumentasi. Analisis data yang digunakan adalah analisis kualitatif dan analisis kuantitatif. Temuan dalam penelitian ini ialah model pembelajaran koopertaif tipe Numbered Head Together dapat meningkatkan hasil belajar siswa kelas VIII pada mata pelajaran Pendidikan Agama Islam di SMP Islam Unggulan Miftaahul ‘Uluum Bandar Sribhawono, hal ini dibuktikan dengan adanya peningkatan hasil belajar dengan rata-rata 70,95 pada siklus I dan 79,90 pada siklus II, dengan presentase peningkatan hasil belajar yaitu 60% pada siklus I dan 90% pada siklus II.

  7. Traumatic Head Injury: Dimensions of Family Responsivity.

    Science.gov (United States)

    Zarski, John J.; And Others

    1988-01-01

    Forty-five parents or spouses of head-injured patients were studied to: (1) determine differences among various family types on clinically relevant dimensions of family functioning, based on Olson's Circumplex model, and (2) establish the validity of three assessment methods. Results showed family functioning to be an important factor in recovery.…

  8. Where are we heading

    International Nuclear Information System (INIS)

    Noto, L.A.

    1996-01-01

    The present paper deals with different aspects connected to the global petroleum industry by discussing the way of heading. The aspects cover themes like new frontiers, new relationships, sanctions, global climate change, new alliances and new technology. New frontiers and relationships concern domestic policy affecting the industry, and sanctions are discussed in connection with trade. The author discusses the industry's participation in the global environmental policy and new alliances to provide greater opportunity for developing new technology

  9. Where are we heading

    Energy Technology Data Exchange (ETDEWEB)

    Noto, L.A. [Mobil Corporation, (United States)

    1996-12-31

    The present paper deals with different aspects connected to the global petroleum industry by discussing the way of heading. The aspects cover themes like new frontiers, new relationships, sanctions, global climate change, new alliances and new technology. New frontiers and relationships concern domestic policy affecting the industry, and sanctions are discussed in connection with trade. The author discusses the industry`s participation in the global environmental policy and new alliances to provide greater opportunity for developing new technology

  10. Head segmentation in vertebrates

    OpenAIRE

    Kuratani, Shigeru; Schilling, Thomas

    2008-01-01

    Classic theories of vertebrate head segmentation clearly exemplify the idealistic nature of comparative embryology prior to the 20th century. Comparative embryology aimed at recognizing the basic, primary structure that is shared by all vertebrates, either as an archetype or an ancestral developmental pattern. Modern evolutionary developmental (Evo-Devo) studies are also based on comparison, and therefore have a tendency to reduce complex embryonic anatomy into overly simplified patterns. Her...

  11. Review : Hydraulic head measurements - New technologies, classic pitfalls

    NARCIS (Netherlands)

    Post, E.A.P.; Von Asmuth, J.R.

    2013-01-01

    The hydraulic head is one of the most important metrics in hydrogeology as it underlies the interpretation of groundwater flow, the quantification of aquifer properties and the calibration of flow models. Heads are determined based on water-level measurements in wells and piezometers. Despite the

  12. Biomechanics of Heading a Soccer Ball: Implications for Player Safety

    Directory of Open Access Journals (Sweden)

    Charles F. Babbs

    2001-01-01

    Full Text Available To better understand the risk and safety of heading a soccer ball, the author created a set of simple mathematical models based upon Newton�s second law of motion to describe the physics of heading. These models describe the player, the ball, the flight of the ball before impact, the motion of the head and ball during impact, and the effects of all of these upon the intensity and the duration of acceleration of the head. The calculated head accelerations were compared to those during presumably safe daily activities of jumping, dancing, and head nodding and also were related to established criteria for serious head injury from the motor vehicle crash literature. The results suggest heading is usually safe but occasionally dangerous, depending on key characteristics of both the player and the ball. Safety is greatly improved when players head the ball with greater effective body mass, which is determined by a player�s size, strength, and technique. Smaller youth players, because of their lesser body mass, are more at risk of potentially dangerous headers than are adults, even when using current youth size balls. Lower ball inflation pressure reduces risk of dangerous head accelerations. Lower pressure balls also have greater “touch” and “playability”, measured in terms of contact time and contact area between foot and ball during a kick. Focus on teaching proper technique, the re-design of age-appropriate balls for young players with reduced weight and inflation pressure, and avoidance of head contact with fast, rising balls kicked at close range can substantially reduce risk of subtle brain injury in players who head soccer balls.

  13. Head pulsations in a centrifugal pump

    Science.gov (United States)

    Boiko, V. S.; Sotnyk, M. I.; Moskalenko, V. V.

    2017-08-01

    This article investigated the factors, which affect to the character of the head pulsations of a centrifugal pump. We investigated the dependence of the shape and depth of these pulsations from the operation mode of the pump. Was determined, that the head pulsations at the outlet of the impeller (pulsations on the blade passing frequency) cause head pulsations at the outlet of the pump, that have the same frequency, but differ in shape and depth. These pulsations depend on the design features of the flow-through part of the pump (from the ratio of hydraulic losses on the friction and losses on the vortex formation). A feature of the researches that were conducted is also the using of not only hydraulic but also electric modeling methods. It allows determining the values of the components of hydraulic losses.

  14. Head Lice: Frequently Asked Questions (FAQs)

    Science.gov (United States)

    ... spread lice? Can swimming spread lice? What are head lice? The head louse, or Pediculus humanus capitis , ... spread disease. Who is at risk for getting head lice? Head lice are found worldwide. In the ...

  15. The impact of gravity during head-up tilt

    DEFF Research Database (Denmark)

    Ottesen, Johnny T.; Olufsen, Mette; Smith, Brittany

    2011-01-01

    and the carotid sinuses in a healthy volunteer. During head-up tilt the head is lifted above the heart stimulating gravitational pooling of blood in the lower extremities. This shift in volume is followed by an increase in blood pressure in the lower body, while the pressure in the head decreases, while...... a model predicting hydrostatic height between the two locations. Results from this model were compared with measurements. Furthermore, we show, using a differential equations model predicting blood pressure, that it is possible to predict blood pressure measured at the level of the carotid sinuses using...

  16. Dose–Volume Modeling of Brachial Plexus-Associated Neuropathy After Radiation Therapy for Head-and-Neck Cancer: Findings From a Prospective Screening Protocol

    International Nuclear Information System (INIS)

    Chen, Allen M.; Wang, Pin-Chieh; Daly, Megan E.; Cui, Jing; Hall, William H.; Vijayakumar, Srinivasan; Phillips, Theodore L.; Farwell, D. Gregory; Purdy, James A.

    2014-01-01

    Purpose: Data from a prospective screening protocol administered for patients previously irradiated for head-and-neck cancer was analyzed to identify dosimetric predictors of brachial plexus-associated neuropathy. Methods and Materials: Three hundred fifty-two patients who had previously completed radiation therapy for squamous cell carcinoma of the head and neck were prospectively screened from August 2007 to April 2013 using a standardized self-administered instrument for symptoms of neuropathy thought to be related to brachial plexus injury. All patients were disease-free at the time of screening. The median time from radiation therapy was 40 months (range, 6-111 months). A total of 177 patients (50%) underwent neck dissection. Two hundred twenty-one patients (63%) received concurrent chemotherapy. Results: Fifty-one patients (14%) reported brachial plexus-related neuropathic symptoms with the most common being ipsilateral pain (50%), numbness/tingling (40%), and motor weakness and/or muscle atrophy (25%). The 3- and 5-year estimates of freedom from brachial plexus-associated neuropathy were 86% and 81%, respectively. Clinical/pathological N3 disease (P<.001) and maximum radiation dose to the ipsilateral brachial plexus (P=.01) were significantly associated with neuropathic symptoms. Cox regression analysis revealed significant dose–volume effects for brachial plexus-associated neuropathy. The volume of the ipsilateral brachial plexus receiving >70 Gy (V70) predicted for symptoms, with the incidence increasing with V70 >10% (P<.001). A correlation was also observed for the volume receiving >74 Gy (V74) among patients treated without neck dissection, with a cutoff of 4% predictive of symptoms (P=.038). Conclusions: Dose–volume guidelines were developed for radiation planning that may limit brachial plexus-related neuropathies

  17. Dose–Volume Modeling of Brachial Plexus-Associated Neuropathy After Radiation Therapy for Head-and-Neck Cancer: Findings From a Prospective Screening Protocol

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Allen M., E-mail: amchen@mednet.ucla.edu [Department of Radiation Oncology, University of California, Los Angeles, David Geffen School of Medicine, Los Angeles, California (United States); Wang, Pin-Chieh [Department of Radiation Oncology, University of California, Los Angeles, David Geffen School of Medicine, Los Angeles, California (United States); Daly, Megan E.; Cui, Jing; Hall, William H. [Department of Radiation Oncology, University of California, Davis, Comprehensive Cancer Center, Sacramento, California (United States); Vijayakumar, Srinivasan [Department of Radiation Oncology, University of Mississippi School of Medicine, Jackson, Mississippi (United States); Phillips, Theodore L. [Department of Radiation Oncology, University of California, Davis, Comprehensive Cancer Center, Sacramento, California (United States); Farwell, D. Gregory [Department of Otolaryngology–Head and Neck Surgery, University of California, Davis, Comprehensive Cancer Center, Sacramento, California (United States); Purdy, James A. [Department of Radiation Oncology, University of California, Davis, Comprehensive Cancer Center, Sacramento, California (United States)

    2014-03-15

    Purpose: Data from a prospective screening protocol administered for patients previously irradiated for head-and-neck cancer was analyzed to identify dosimetric predictors of brachial plexus-associated neuropathy. Methods and Materials: Three hundred fifty-two patients who had previously completed radiation therapy for squamous cell carcinoma of the head and neck were prospectively screened from August 2007 to April 2013 using a standardized self-administered instrument for symptoms of neuropathy thought to be related to brachial plexus injury. All patients were disease-free at the time of screening. The median time from radiation therapy was 40 months (range, 6-111 months). A total of 177 patients (50%) underwent neck dissection. Two hundred twenty-one patients (63%) received concurrent chemotherapy. Results: Fifty-one patients (14%) reported brachial plexus-related neuropathic symptoms with the most common being ipsilateral pain (50%), numbness/tingling (40%), and motor weakness and/or muscle atrophy (25%). The 3- and 5-year estimates of freedom from brachial plexus-associated neuropathy were 86% and 81%, respectively. Clinical/pathological N3 disease (P<.001) and maximum radiation dose to the ipsilateral brachial plexus (P=.01) were significantly associated with neuropathic symptoms. Cox regression analysis revealed significant dose–volume effects for brachial plexus-associated neuropathy. The volume of the ipsilateral brachial plexus receiving >70 Gy (V70) predicted for symptoms, with the incidence increasing with V70 >10% (P<.001). A correlation was also observed for the volume receiving >74 Gy (V74) among patients treated without neck dissection, with a cutoff of 4% predictive of symptoms (P=.038). Conclusions: Dose–volume guidelines were developed for radiation planning that may limit brachial plexus-related neuropathies.

  18. Low head hydro market assessment : main report : vol. 1

    International Nuclear Information System (INIS)

    2008-03-01

    Hydroelectric power is a predictable renewable energy source that produces no greenhouse gases (GHGs) and has low maintenance costs. In addition to river resources, low head hydro is available in sluice gates, irrigation canals, drinking water pressure release valves, and municipal wastewater outfalls. Canada's potential for low head hydro has been estimated at 5000 MW at 2000 different sites across the country. Sites of up to 50 MW have been identified in Ontario and Manitoba. This study performed a market assessment on low head hydro developments. Available and emerging technologies for developing low head hydro were identified. The economics of low head hydro in Canada were explored, and barriers to low head hydro development were identified. Strategies to promote low head hydro development were also explored, and the impact of different incentive types on the low head hydropower market were estimated using a simple economic model. It was concluded that a reduced, streamlined, and standardized environmental assessment process will significantly benefit low head hydro development in Canada. 5 refs., 14 tabs., 17 figs

  19. Head Impact Magnitude in American High School Football.

    Science.gov (United States)

    Schmidt, Julianne D; Guskiewicz, Kevin M; Mihalik, Jason P; Blackburn, J Troy; Siegmund, Gunter P; Marshall, Stephen W

    2016-08-01

    To describe determinants of head impact magnitudes between various play aspects in high school football. Thirty-two high school American football players wore Head Impact Telemetry System instrumented helmets to capture head impact magnitude (linear acceleration, rotational acceleration, and Head Impact Technology severity profile [HITsp]). We captured and analyzed video from 13 games (n = 3888 viewable head impacts) to determine the following play aspects: quarter, impact cause, play type, closing distance, double head impact, player's stance, player's action, direction of gaze, athletic readiness, level of anticipation, player stationary, ball possession, receiving ball, and snapping ball. We conducted random intercepts general linear mixed models to assess the differences in head impact magnitude between play aspects (α = 0.05). The following aspects resulted in greater head impact magnitude: impacts during the second quarter (HITsp: P = .03); contact with another player (linear, rotational, HITsp: P football. Rule or coaching changes that reduce collisions after long closing distances, especially when combined with the 3-point stance or when a player is being struck in the head, should be considered. Copyright © 2016 by the American Academy of Pediatrics.

  20. Simulation of Blast on Porcine Head

    Science.gov (United States)

    2015-07-01

    and small. Animals tested include mice, rats, hamsters, guinea pigs, rabbits, cats, dogs, goats, sheep, burros, swine , monkeys, and cattle for tests...to find eardrum failure threshold, lung damage threshold, and lethality threshold. Scaling models have been developed to find a survivable over...Bell R, Ecklund J, Armonda R, Bandak F, Parks S. An intro characterization of a combat-casualty-care relevant swine model of closed head injury

  1. Head First Web Design

    CERN Document Server

    Watrall, Ethan

    2008-01-01

    Want to know how to make your pages look beautiful, communicate your message effectively, guide visitors through your website with ease, and get everything approved by the accessibility and usability police at the same time? Head First Web Design is your ticket to mastering all of these complex topics, and understanding what's really going on in the world of web design. Whether you're building a personal blog or a corporate website, there's a lot more to web design than div's and CSS selectors, but what do you really need to know? With this book, you'll learn the secrets of designing effecti

  2. Head First Python

    CERN Document Server

    Barry, Paul

    2010-01-01

    Ever wished you could learn Python from a book? Head First Python is a complete learning experience for Python that helps you learn the language through a unique method that goes beyond syntax and how-to manuals, helping you understand how to be a great Python programmer. You'll quickly learn the language's fundamentals, then move onto persistence, exception handling, web development, SQLite, data wrangling, and Google App Engine. You'll also learn how to write mobile apps for Android, all thanks to the power that Python gives you. We think your time is too valuable to waste struggling with

  3. Head First Mobile Web

    CERN Document Server

    Gardner, Lyza; Grigsby, Jason

    2011-01-01

    Despite the huge number of mobile devices and apps in use today, your business still needs a website. You just need it to be mobile. Head First Mobile Web walks you through the process of making a conventional website work on a variety smartphones and tablets. Put your JavaScript, CSS media query, and HTML5 skills to work-then optimize your site to perform its best in the demanding mobile market. Along the way, you'll discover how to adapt your business strategy to target specific devices. Navigate the increasingly complex mobile landscapeTake both technical and strategic approaches to mobile

  4. Head first C#

    CERN Document Server

    Stellman, Andrew

    2008-01-01

    Head First C# is a complete learning experience for object-oriented programming, C#, and the Visual Studio IDE. Built for your brain, this book covers C# 3.0 and Visual Studio 2008, and teaches everything from language fundamentals to advanced topics including garbage collection, extension methods, and double-buffered animation. You'll also master C#'s hottest and newest syntax, LINQ, for querying SQL databases, .NET collections, and XML documents. By the time you're through, you'll be a proficient C# programmer, designing and coding large-scale applications. Every few chapters you will come

  5. Head first C#

    CERN Document Server

    Stellman, Andrew

    2010-01-01

    You want to learn C# programming, but you're not sure you want to suffer through another tedious technical book. You're in luck: Head First C# introduces this language in a fun, visual way. You'll quickly learn everything from creating your first program to learning sophisticated coding skills with C# 4.0, Visual Studio 2010 and .NET 4, while avoiding common errors that frustrate many students. The second edition offers several hands-on labs along the way to help you build and test programs using skills you've learned up to that point. In the final lab, you'll put everything together. From o

  6. The state of head injury biomechanics: past, present, and future part 2: physical experimentation.

    Science.gov (United States)

    Goldsmith, Werner; Monson, Kenneth L

    2005-01-01

    This presentation is the continuation of the article published in Critical Reviews of Biomedical Engineering, 29(5-6), 2001. That issue contained topics dealing with components and geometry of the human head, classification of head injuries, some early experimental studies, and tolerance considerations. It then dealt with head motion and load characterization, investigations during the period from 1939 to 1966, injury causation and early modeling efforts, the 1966 Head Injury Conference and its sequels, mechanical properties of solid tissues, fluid characterization, and early investigation of the mechanical properties of cranial materials. It continued with a description of the systematic investigations of solid cranial components and structural properties since 1966, fetal cranial properties, analytical head modeling, and numerical solutions of head injury. The paper concluded with experimental dynamic loading of human living and cadaver heads, dynamic loading of surrogate heads, and head injury mechanics. This portion of the paper describes physical head injury experimentation involving animals, primarily primates, human cadavers, volunteers, and inanimate physical models. In order to address the entire domain of head injury biomechanics in the two-part survey, it was intended that this information be supplemented by discussions of head injury tolerance and criteria, automotive and sports safety considerations, and the design of protective equipment, but Professor Goldsmith passed away before these sections could be completed. It is nevertheless anticipated that this attenuated installment will provide, in conjunction with the first part of the survey, a valuable resource for students and practitioners of head injury biomechanics.

  7. Photon iso-effective dose for cancer treatment with mixed field radiation based on dose-response assessment from human and an animal model: clinical application to boron neutron capture therapy for head and neck cancer

    Science.gov (United States)

    González, S. J.; Pozzi, E. C. C.; Monti Hughes, A.; Provenzano, L.; Koivunoro, H.; Carando, D. G.; Thorp, S. I.; Casal, M. R.; Bortolussi, S.; Trivillin, V. A.; Garabalino, M. A.; Curotto, P.; Heber, E. M.; Santa Cruz, G. A.; Kankaanranta, L.; Joensuu, H.; Schwint, A. E.

    2017-10-01

    Boron neutron capture therapy (BNCT) is a treatment modality that combines different radiation qualities. Since the severity of biological damage following irradiation depends on the radiation type, a quantity different from absorbed dose is required to explain the effects observed in the clinical BNCT in terms of outcome compared with conventional photon radiation therapy. A new approach for calculating photon iso-effective doses in BNCT was introduced previously. The present work extends this model to include information from dose-response assessments in animal models and humans. Parameters of the model were determined for tumour and precancerous tissue using dose-response curves obtained from BNCT and photon studies performed in the hamster cheek pouch in vivo models of oral cancer and/or pre-cancer, and from head and neck cancer radiotherapy data with photons. To this end, suitable expressions of the dose-limiting Normal Tissue Complication and Tumour Control Probabilities for the reference radiation and for the mixed field BNCT radiation were developed. Pearson’s correlation coefficients and p-values showed that TCP and NTCP models agreed with experimental data (with r  >  0.87 and p-values  >0.57). The photon iso-effective dose model was applied retrospectively to evaluate the dosimetry in tumours and mucosa for head and neck cancer patients treated with BNCT in Finland. Photon iso-effective doses in tumour were lower than those obtained with the standard RBE-weighted model (between 10% to 45%). The results also suggested that the probabilities of tumour control derived from photon iso-effective doses are more adequate to explain the clinical responses than those obtained with the RBE-weighted values. The dosimetry in the mucosa revealed that the photon iso-effective doses were about 30% to 50% higher than the corresponding RBE-weighted values. While the RBE-weighted doses are unable to predict mucosa toxicity, predictions based on the proposed

  8. Live Speech Driven Head-and-Eye Motion Generators.

    Science.gov (United States)

    Le, Binh H; Ma, Xiaohan; Deng, Zhigang

    2012-11-01

    This paper describes a fully automated framework to generate realistic head motion, eye gaze, and eyelid motion simultaneously based on live (or recorded) speech input. Its central idea is to learn separate yet interrelated statistical models for each component (head motion, gaze, or eyelid motion) from a prerecorded facial motion data set: 1) Gaussian Mixture Models and gradient descent optimization algorithm are employed to generate head motion from speech features; 2) Nonlinear Dynamic Canonical Correlation Analysis model is used to synthesize eye gaze from head motion and speech features, and 3) nonnegative linear regression is used to model voluntary eye lid motion and log-normal distribution is used to describe involuntary eye blinks. Several user studies are conducted to evaluate the effectiveness of the proposed speech-driven head and eye motion generator using the well-established paired comparison methodology. Our evaluation results clearly show that this approach can significantly outperform the state-of-the-art head and eye motion generation algorithms. In addition, a novel mocap+video hybrid data acquisition technique is introduced to record high-fidelity head movement, eye gaze, and eyelid motion simultaneously.

  9. [Prediction of femoral remodeling after implantation of artifical femoral head].

    Science.gov (United States)

    Gao, Zhongli; Zhao, Changfu; Yu, Qingwei; Wu, Dankai; Yu, Jingwei

    2003-06-01

    By integrating bone-remodeling theory with finite element (FEM) models, the behavior of femoral remodeling after implantation of artificial femoral head was simulated and the stress shield effect of artificial femoral head on the femur was analyzed quantitatively. Bone was calculated with finite element code of the FEM model. The normal loading condition of femur was used as Model One, and the stress condition that bone was fixed by the bone-cement of the artificial head with collar was used as Model Two. It has been shown that bone was stress-shielded by the artificial femoral head and femur resorbed. Bone resorption near the proximal artificial stem was very severe. Its cross-section resorbed the greatest. The ratio of cross-sectional resorption was psi = 31.3% and the ratio of loss of the anti-bend cross-sectional modulus was zeta = 54.58%.

  10. 31P nuclear magnetic resonance chemical shielding tensors of phosphorylethanolamine, lecithin, and related compounds: Applications to head-group motion in model membranes.

    Science.gov (United States)

    Kohler, S J; Klein, M P

    1976-03-09

    31P nuclear magnetic resonance (NMR) powder spectra have been used to obtain the principal values of the chemical shielding tensors of dipalmitoyellecithin (DPL), dipalmitoylphosphatidylethanolamine, and several related organophosphate mono- and diesters. In addition, the principal values and orientation of the phosphorylethanolamine shielding tensor were determined from 31P NMR spectra of a single crystal. In all compounds studied the shielding tensors were clearly monaxial. The monoester spectra are typified by the spectrum of phosphorylethanolamine with principal values of -67, -13, and 69 ppm relative to H3PO4. The diesters have a larger total anisotrophy, as indicated by the DPL values of -81, -25, and 108 ppm. These data as well as the orientation of the phosphorylethanolamine shielding tensor are correlated with the electron density distribution as determined by the bonding pattern of the phosphate. The spectrum of a DPL-water (1:1) mixture at 52 degrees C has a shift anisotrophy of 30 ppm and displays a shape characteristic of an axial tensor. This change from the rigid lattice DPL pattern is explained in terms of motional narrowing, and the shielding tensor data are used to interpret the motion of the phospholipid head group. Simple rotation about the P-O(glycerol) bond is excluded, and a more complex motion involving rotation about both the P-O (glycerol) and glycerol C(2)-C(3) bonds is postulated.

  11. /sup 31/P nuclear magnetic resonance chemical shielding tensors of phosphorylethanolamine, lecithin, and related compounds: applications to head-group motion in model membranes

    Energy Technology Data Exchange (ETDEWEB)

    Kohler, S.J.; Klein, M.P.

    1976-03-09

    /sup 31/P nuclear magnetic resonance (NMR) power spectra have been used to obtain the principal values of the chemical shielding tensors of dipalmitoyllecithin (DPL), dipalmitoylphosphatidylethanolamine, and several related organophosphate mono- and diesters. In addition, the principal values and orientation of the phosphorylethanolamine shielding tensor were determined from /sup 31/P NMR spectra of a single crystal. In all compounds studied the shielding tensors were clearly nonaxial. The monoester spectra are typified by the spectrum of phosphorylethanolamine with principal values of -67, -13, and 69 ppm relative to H/sub 3/PO/sub 4/. The diesters have a larger total anisotropy, as indicated by the DPL values of -81, -25, and 108 ppm. These data as well as the orientation of the phosphorylethanolamine shielding tensor are correlated with the electron density distribution as determined by the bonding pattern of the phosphate. The spectrum of a DPL--water (1:1) mixture at 52/sup 0/C has a shift anisotropy of 30 ppm and displays a shape characteristic of an axial tensor. This change from the rigid lattice DPL pattern is explained in terms of motional narrowing, and the shielding tensor data are used to interpret the motion of the phospholipid head group. Simple rotation about the P--O(glycerol) bond is excluded, and a more complex motion involving rotation about both the P--O(glycerol) and glycerol C(2)--C(3) bonds is postulated. (auth)

  12. Rat Cardiovascular Responses to Whole Body Suspension: Head-down and Non-Head-Down Tilt

    Science.gov (United States)

    Musacchia, X. J.; Steffen, Joseph M.; Dombrowski, Judy

    1992-01-01

    The rat whole body suspension technique mimics responses seen during exposure to microgravity and was evaluated as a model for cardiovascular responses with two series of experiments. In one series, changes were monitored in chronically catheterized rats during 7 days of Head-Down Tilt (HDT) or Non-Head-Down Tilt (N-HDT) and after several hours of recovery. Elevations of mean arterial (MAP), systolic, and diastolic pressures of approx. 20 % (P less than 0.05) in HDT rats began as early as day 1 and were maintained for the duration of suspension. Pulse pressures were relatively unaffected, but heart rates were elevated approx. 10 %. During postsuspension (2-7 h), most cardiovascular parameters returned to presuspension levels. N-HDT rats exhibited elevations chiefly on days 3 and 7. In the second series, blood pressure was monitored in 1- and 3-day HDT and N-HDT rats to evaluate responses to rapid head-up tilt. MAP, systolic and diastolic pressures, and HR were elevated (P less than 0.05) in HDT and N-HDT rats during head-up tilt after 1 day of suspension, while pulse pressures remained un changed. HDT rats exhibited elevated pretilt MAP and failed to respond to rapid head-up tilt with further increase of MAP on day 3, indicating some degree of deconditioning. The whole body suspended rat may be useful as a model to better understand responses of rats exposed to microgravity.

  13. Eye-based head gestures

    DEFF Research Database (Denmark)

    Mardanbegi, Diako; Witzner Hansen, Dan; Pederson, Thomas

    2012-01-01

    A novel method for video-based head gesture recognition using eye information by an eye tracker has been proposed. The method uses a combination of gaze and eye movement to infer head gestures. Compared to other gesture-based methods a major advantage of the method is that the user keeps the gaze...... on the interaction object while interacting. This method has been implemented on a head-mounted eye tracker for detecting a set of predefined head gestures. The accuracy of the gesture classifier is evaluated and verified for gaze-based interaction in applications intended for both large public displays and small...

  14. A COMPARISON OF DOSE-RESPONSE MODELS FOR THE PAROTID GLAND IN A LARGE GROUP OF HEAD-AND-NECK CANCER PATIENTS

    NARCIS (Netherlands)

    Houweling, Antonetta C.; Philippens, Marielle E. P.; Dijkema, Tim; Roesink, Judith M.; Terhaard, Chris H. J.; Schilstra, Cornelis; Ten Haken, Randall K.; Eisbruch, Avraham; Raaijmakers, Cornelis P. J.

    2010-01-01

    Purpose: The dose response relationship of the parotid gland has been described most frequently using the Lyman-Kutcher-Burman model. However, various other normal tissue complication probability (NTCP) models exist. We evaluated in a large group of patients the value of six NTCP models that

  15. Experimentation of cooperative learning model Numbered Heads Together (NHT) type by concept maps and Teams Games Tournament (TGT) by concept maps in terms of students logical mathematics intellegences

    Science.gov (United States)

    Irawan, Adi; Mardiyana; Retno Sari Saputro, Dewi

    2017-06-01

    This research is aimed to find out the effect of learning model towards learning achievement in terms of students’ logical mathematics intelligences. The learning models that were compared were NHT by Concept Maps, TGT by Concept Maps, and Direct Learning model. This research was pseudo experimental by factorial design 3×3. The population of this research was all of the students of class XI Natural Sciences of Senior High School in all regency of Karanganyar in academic year 2016/2017. The conclusions of this research were: 1) the students’ achievements with NHT learning model by Concept Maps were better than students’ achievements with TGT model by Concept Maps and Direct Learning model. The students’ achievements with TGT model by Concept Maps were better than the students’ achievements with Direct Learning model. 2) The students’ achievements that exposed high logical mathematics intelligences were better than students’ medium and low logical mathematics intelligences. The students’ achievements that exposed medium logical mathematics intelligences were better than the students’ low logical mathematics intelligences. 3) Each of student logical mathematics intelligences with NHT learning model by Concept Maps has better achievement than students with TGT learning model by Concept Maps, students with NHT learning model by Concept Maps have better achievement than students with the direct learning model, and the students with TGT by Concept Maps learning model have better achievement than students with Direct Learning model. 4) Each of learning model, students who have logical mathematics intelligences have better achievement then students who have medium logical mathematics intelligences, and students who have medium logical mathematics intelligences have better achievement than students who have low logical mathematics intelligences.

  16. Chryse 'Alien Head'

    Science.gov (United States)

    2005-01-01

    26 January 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an impact crater in Chryse Planitia, not too far from the Viking 1 lander site, that to seems to resemble a bug-eyed head. The two odd depressions at the north end of the crater (the 'eyes') may have formed by wind or water erosion. This region has been modified by both processes, with water action occurring in the distant past via floods that poured across western Chryse Planitia from Maja Valles, and wind action common occurrence in more recent history. This crater is located near 22.5oN, 47.9oW. The 150 meter scale bar is about 164 yards long. Sunlight illuminates the scene from the left/lower left.

  17. Head trauma and CT

    International Nuclear Information System (INIS)

    Samejima, Kanji; Yoshii, Nobuo; Tobari, Chitoshi

    1979-01-01

    In our cases of acute and subacute subdural hematoma, the use of CT was evaluated. In our department of surgery, acute subdural hematoma was found in 46 of 388 patients of head trauma who underwent CT. Acute subdural hematoma, like epidural hematoma was usually visualized as a high-density area along the cranial inner table, and this was easily differenciated from epidural hematoma because of difference in shape from the other. The picture of acute subdural hematoma was occasionally confused with that of intracerebral hematoma or cerebral contusion. Single use of CT does not differenciate subacute subdural hematoma from chronic subdural hematoma. However, CT usually visualized acute hematoma as a high-density area, showing the extent of hematoma. Comparison of the thickness of hematoma with the axis deviation of the median part such as the 3rd cerebral ventricle suggested severity of cerebral edema. CT also revealed bilateral or multiple lesions of cerebral contusion or intracerebral hematoma. (Ueda, J.)

  18. Actors with Multi-Headed Message Receive Patterns

    DEFF Research Database (Denmark)

    Sulzmann, Martin; Lam, Edmund Soon Lee; Van Weert, Peter

    2008-01-01

    The actor model provides high-level concurrency abstractions to coordinate simultaneous computations by message passing. Languages implementing the actor model such as Erlang commonly only support single-headed pattern matching over received messages. We propose and design an extension of Erlang...... style actors with receive clauses containing multi-headed message patterns. Patterns may be non-linear and constrained by guards. We provide a number of examples to show the usefulness of the extension. We also explore the design space for multi-headed message matching semantics, for example first......-match and rule priority-match semantics. The various semantics are inspired by the multi-set constraint matching semantics found in Constraint Handling Rules. This provides us with a formal model to study actors with multi-headed message receive patterns. The system can be implemented efficiently and we have...

  19. Proteome reference map of Drosophila melanogaster head.

    Science.gov (United States)

    Lee, Tian-Ren; Huang, Shun-Hong; Lee, Chi-Ching; Lee, Hsiao-Yun; Chan, Hsin-Tzu; Lin, Kuo-Sen; Chan, Hong-Lin; Lyu, Ping-Chiang

    2012-06-01

    Drosophila melanogaster has been used as a genetic model organism to understand the fundamental molecular mechanisms in human biology including memory formation that has been reported involving protein synthesis and/or post-translational modification. In this study, we employed a proteomic platform based on fluorescent 2DE and MALDI-TOF MS to build a standard D. melanogaster head proteome map for proteome-proteome comparison. In order to facilitate the comparison, an interactive database has been constructed for systematically integrating and analyzing the proteomes from different conditions and further implicated to study human diseases related to D. melanogaster model. In summary, the fundamental head proteomic database and bioinformatic analysis will be useful for further elucidating the biological mechanisms such as memory formation and neurodegenerative diseases. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... bear denotes child-specific content. Related Articles and Media MR Angiography (MRA) Magnetic Resonance, Functional (fMRI) - Brain Head and Neck Cancer Treatment Brain Tumor Treatment Magnetic Resonance Imaging (MRI) Safety Alzheimer's Disease Head Injury Brain Tumors Images related to Magnetic ...

  1. Flat Head Syndrome (Positional Plagiocephaly)

    Science.gov (United States)

    ... itself out. Although they're very simple, the exercises must be done correctly. For kids with severe flat head syndrome in which repositioning for 2-3 months doesn't help, doctors may prescribe a custom-molded helmet or head band. While helmets might ...

  2. Womanhood in Bessie Head's fiction

    African Journals Online (AJOL)

    Rain Cloud~· Gather ( 1969), Maru ( 1972) and A Question of Power ( 1974 ),. Head addresses and deals with ... In A Question of Power, Head deals with these groups through. Kenosi and Elizabeth respectively. ... environment, Mma Millipede soon establishes herself through her hard work and unique individuality which ...

  3. The head-mounted microscope.

    Science.gov (United States)

    Chen, Ting; Dailey, Seth H; Naze, Sawyer A; Jiang, Jack J

    2012-04-01

    Microsurgical equipment has greatly advanced since the inception of the microscope into the operating room. These advancements have allowed for superior surgical precision and better post-operative results. This study focuses on the use of the Leica HM500 head-mounted microscope for the operating phonosurgeon. The head-mounted microscope has an optical zoom from 2× to 9× and provides a working distance from 300 mm to 700 mm. The headpiece, with its articulated eyepieces, adjusts easily to head shape and circumference, and offers a focus function, which is either automatic or manually controlled. We performed five microlaryngoscopic operations utilizing the head-mounted microscope with successful results. By creating a more ergonomically favorable operating posture, a surgeon may be able to obtain greater precision and success in phonomicrosurgery. Phonomicrosurgery requires the precise manipulation of long-handled cantilevered instruments through the narrow bore of a laryngoscope. The head-mounted microscope shortens the working distance compared with a stand microscope, thereby increasing arm stability, which may improve surgical precision. Also, the head-mounted design permits flexibility in head position, enabling operator comfort, and delaying musculoskeletal fatigue. A head-mounted microscope decreases the working distance and provides better ergonomics in laryngoscopic microsurgery. These advances provide the potential to promote precision in phonomicrosurgery. Copyright © 2011 The American Laryngological, Rhinological, and Otological Society, Inc.

  4. Return of the talking heads

    DEFF Research Database (Denmark)

    Reinecke Hansen, Kenneth; Bro, Peter; Andersson, Ralf

    2016-01-01

    The present article suggests that the brief history of Western television news dramaturgy can be expounded as three major waves: from the early days of the talking heads in the studio, over the narrativization of the field report to a (re-)current studio- and field-based talking heads format...

  5. Head-twitch response in rodents induced by the hallucinogen 2,5-dimethoxy-4-iodoamphetamine: a comprehensive history, a re-evaluation of mechanisms, and its utility as a model

    Science.gov (United States)

    Canal, Clint E.; Morgan, Drake

    2013-01-01

    Two primary animal models persist for assessing hallucinogenic potential of novel compounds and for examining the pharmacological and neurobiological substrates underlying the actions of classical hallucinogens, the two-lever drug discrimination procedure and the drug-induced head-twitch response (HTR) in rodents. The substituted amphetamine hallucinogen, serotonin 2 (5-HT2) receptor agonist, 2,5-dimethoxy-4-iodoamphetamine (DOI) has emerged as the most popular pharmacological tool used in HTR studies of hallucinogens. Synthesizing classic, recent, and relatively overlooked findings, addressing ostensibly conflicting observations, and considering contemporary theories in receptor and behavioural pharmacology, this review provides an up-to-date and comprehensive synopsis of DOI and the HTR model, from neural mechanisms to utility for understanding psychiatric diseases. Also presented is support for the argument that, although both the two-lever drug discrimination and the HTR models in rodents are useful for uncovering receptors, interacting proteins, intracellular signalling pathways, and neurochemical processes affected by DOI and related classical hallucinogens, results from both models suggest they are not reporting hallucinogenic experiences in animals. PMID:22517680

  6. PENERAPAN MODEL PEMBELAJARAN KOOPERATIF TIPE JIGSAW DAN NUMBERED HEADS TOGETHER DITINJAU DARI KECERDASAN INTERPERSONAL SISWA PADA POKOK BAHASAN BANGUN RUANG SISI DATAR

    Directory of Open Access Journals (Sweden)

    Kiki Riska Ayu Kurniawati

    2017-01-01

    Full Text Available The current research intends to investigate the different effect of each categories of learning model, students interpersonal intelligence and their interaction towards students mathematics learning achievement on the subject of plane geometry. The research was quasi experimental with 3×3 factorial design. The population was all students of grade VIII State Junior High School in Madiun City on the second semester of 2013/2014 academic years. Sampling was done by stratified cluster random sampling technique. The sample of this research consisted of the students of SMP N 3 Madiun, SMPN 7 Madiun, and SMPN 10 Madiun. The sample consisted of 260 students. The hypothesis test used unbalanced two ways analysis of variance at the significance level of 0,05. Based on hypothesis test, it can be concluded that: (1 the cooperative learning model of Jigsaw type gives a better mathematics achievement than cooperative learning model of NHT type and direct learning model, and the cooperative learning model of NHT type gives a better mathematics achievement than direct learning model; (2 students with the high interpersonal intelligence had the same achievement as students with the medium interpersonal intelligence, students with the high interpersonal intelligence had better achievement than students with the low interpersonal intelligence and the students with the medium interpersonal intelligence had the same achievement as students with the low interpersonal intelligence; (3 on the cooperative learning model of Jigsaw type, NHT type and direct learning model, students with the high interpersonal intelligence had the same achievement as students with the medium interpersonal intelligence, students with the high interpersonal intelligence had better achievement than students with the low interpersonal intelligence and the students with the medium interpersonal intelligence had the same achievement as students with the low interpersonal intelligence; and (4 on

  7. WE-EF-BRA-12: Magnetic Resonance- Guided High-Intensity Focused Ultrasound for Localized Ablation of Head and Neck Tissue Structures: A Feasibility Study in An Animal Model

    Energy Technology Data Exchange (ETDEWEB)

    Partanen, A [Philips Healthcare, Andover, Massachusets (United States); Ellens, N; Noureldine, S; Tufano, R [Johns Hopkins University School of Medicine, Baltimore, MD (United States); Burdette, E [Acoustic MedSystems Inc., Savoy, IL (United States); Farahani, K [National Cancer Institute, Bethesda, MD (United States)

    2015-06-15

    Purpose: High-intensity focused ultrasound (HIFU) ablation is feasible in the head and neck [1]. This study aims to expand upon these findings to assess the feasibility of treatment planning and monitoring via magnetic resonance imaging (MRI) guidance using a clinical MR-guided HIFU platform. Methods: Two 31 kg pigs were anaesthetized, shaved, and positioned prone on the HIFU table (Sonalleve, Philips Healthcare, Vantaa, Finland). The necks were acoustically coupled to the integrated transducer using gel pads and degassed water. MR imaging verified acoustic coupling and facilitated target selection in the thyroid and thymus. Targets were thermally ablated with 130–200 W of acoustic power over a period of 16 s at a frequency of 1.2 MHz while being monitored through real-time, multi-planar MR-thermometry. Contrast-enhanced MR imaging was used to assess treatment efficacy. Post-treatment, animals were euthanized and sonicated tissues were harvested for histology assessment. Results: MR-thermometry, post-contrast-imaging, and gross pathology demonstrated that the system was capable of causing localized thermal ablation in both the thyroid and the thymus without damaging the aerodigestive tract. In one animal, superficial bruising was observed in the ultrasound beam path. Otherwise, there were no adverse events. Analysis of the tissue histology found regions of damage consistent with acute thermal injury at the targeted locations. Conclusion: It is feasible to use a clinical MR-guided HIFU platform for extracorporeal ablation of porcine head and neck tissues. MR guidance and thermometry are sufficient to target and monitor treatment in the thyroid region, despite the presence of the inhomogeneous aerodigestive tract. Further study is necessary to assess efficacy and survival using a tumor model, and to examine what modifications should be made to the transducer positioning system and associated patient positioning aids to adapt it for clinical head and neck targets

  8. Modelling of Biota Dose Effects. Report of Working Group 6 Biota Dose Effects Modelling of EMRAS II Topical Heading Reference Approaches for Biota Dose Assessment. Environmental Modelling for RAdiation Safety (EMRAS II) Programme

    International Nuclear Information System (INIS)

    2014-07-01

    Environmental assessment models are used for evaluating the radiological impact of actual and potential releases of radionuclides to the environment. They are essential tools for use in the regulatory control of routine discharges to the environment and in planning the measures to be taken in the event of accidental releases. They are also used for predicting the impact of releases which may occur far into the future, for example, from underground radioactive waste repositories. It is important to verify, to the extent possible, the reliability of the predictions of such models by a comparison with measured values in the environment or with the predictions of other models. The IAEA has been organizing programmes on international model testing since the 1980s. These programmes have contributed to a general improvement in models, in the transfer of data and in the capabilities of modellers in Member States. IAEA publications on this subject over the past three decades demonstrate the comprehensive nature of the programmes and record the associated advances which have been made. From 2009 to 2011, the IAEA organized a project entitled Environmental Modelling for RAdiation Safety (EMRAS II), which concentrated on the improvement of environmental transfer models and the development of reference approaches to estimate the radiological impacts on humans, as well as on flora and fauna, arising from radionuclides in the environment. Different aspects were addressed by nine working groups covering three themes: reference approaches for human dose assessment, reference approaches for biota dose assessment and approaches for addressing emergency situations. This publication describes the work of the Biota Effects Modelling Working Group

  9. PENGARUH PENERAPAN MODEL PEMBELAJARAN KOOPERATIF TIPE JIGSAW DENGAN TEKNIK PEMBELAJARAN MAKE A MATCH DAN NUMBERED HEADS TOGETHER TERHADAP PRESTASI BELAJAR MATEMATIKA DITINJAU DARI KECERDASAN GANDA SISWA

    Directory of Open Access Journals (Sweden)

    Budiyono Budiyono

    2014-02-01

    Full Text Available Tujuan penelitian ini adalah untuk menyelidiki : ( 1 yang model J - MAM , J - NHT , dan hasil pembelajaran konvensional pada prestasi belajar yang lebih baik di Matematika pembelajaran , (2 multiple intelligence dari Logical - Mathematical yang , Visual - Spasial , dan interpersonal hasil jenis dalam prestasi belajar yang lebih baik di Matematika , (3 di setiap multiple intelligence , yang model J - MAM , J - NHT , dan hasil pembelajaran konvensional pada prestasi belajar yang lebih baik di Matematika belajar ; dan ( 4 di masing-masing model pembelajaran , yang multiple intelligence dari Logical - Mathematical , Visual - Spasial , dan interpersonal hasil jenis dalam prestasi belajar yang lebih baik di Matematika . Penelitian ini menggunakan metode penelitian eksperimen kuasi dengan desain faktorial 3 x 3 . Populasinya adalah semua siswa di kelas XI SMK Negeri di Kabupaten Sragen . Sampel penelitian diambil dengan menggunakan teknik stratified random sampling . Data penelitian dianalisis dengan menggunakan analisis dua arah tidak seimbang varians pada tingkat signifikansi 5 % . Hasil dari penelitian ini adalah sebagai berikut : 1 The J - MAM dan model pembelajaran J- NHT menghasilkan prestasi belajar yang sama di Matematika , tapi baik mengakibatkan prestasi belajar yang lebih baik di Matematika dibandingkan dengan model pembelajaran konvensional , 2 Ada tidak ada perbedaan dalam prestasi belajar Matematika siswa dengan Logical - Mathematical , Visual - Spasial , dan jenis Interpersonal , 3 dalam setiap jenis multiple intelligence , J- MAM dan model pembelajaran J- NHT menghasilkan barang yang sama prestasi dalam Matematika , namun kedua hasil dalam prestasi belajar yang lebih baik di Matematika dibandingkan dengan model pembelajaran konvensional pembelajaran , 4 dalam setiap model pembelajaran , para siswa dengan Logical - Mathematical , Visual - Spasial , dan jenis interpersonal memiliki prestasi belajar yang sama di Matematika.

  10. Femoral head necrosis; Hueftkopfnekrose

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, J.; Scheurecker, G.; Scheurecker, A.; Stoeger, A.; Huber, A. [Roentgeninstitut am Schillerpark, Linz (Austria); Hofmann, S. [Orthopaedisches Landeskrankenhaus Stolzalpe (Austria)

    2009-05-15

    The epidemiology and pathohistogenesis of avascular femoral head necrosis has still not been clarified in detail. Because the course of the disease runs in stages and over a long time period nearly always culminates in the necessity for a total hip prosthesis, an exact radiological evaluation is of paramount importance for the treatment. There is a need for a common staging system to enable comparison of different therapy concepts and especially their long-term results. In this article the ARCO staging system is described in full detail, which includes all radiological modalities as well as histopathological alterations. (orig.) [German] Bei der avaskulaeren Femurkopfnekrose handelt es sich um ein Krankheitsbild, dessen Ursachen noch immer nicht vollstaendig geklaert sind. Da die Erkrankung stadienhaft verlaeuft und ueber einen laengeren Zeitraum betrachtet nahezu immer in einem prothetischen Hueftersatz muendet, ist eine genaue radiologische Abklaerung fuer die Behandlung von enormer Bedeutung. Um Langzeiterfolge verschiedener Therapiekonzepte vergleichen zu koennen, sind eine exakte Beschreibung und darauf basierend die Verwendung einer einheitlichen Stadieneinteilung wuenschenswert. In der vorliegenden Arbeit wird die ARCO-Stadieneinteilung im Detail beschrieben, die alle bildgebenden Methoden beruecksichtigt und histopathologische Veraenderungen mit einbezieht. (orig.)

  11. Head trauma and CT

    International Nuclear Information System (INIS)

    Samejima, Kanji; Yoshii, Nobuo; Tobari, Chitoshi

    1979-01-01

    It has been said that chronic subdural hematoma cannot be diagnosed by CT. In our cases, CT was used, and the results were described. According to the density of the picture, CT findings of chronic subdural hematoma could be classified into 3 types, those of higher density than that of the cerebral paranchyma, those of isodensity, and those of lower density than that of the cerebral parenchyma. The difference among them appeared to be due to variation in the fluid in hematoma, especially that in hemoglobin concentration. Chronic subdural hematoma was found in 27 of 388 cases of head trauma in which CT was undertaken in our department of surgery for last 2 years. It is difficult to differenciate this disease from subdural edema or subarachnoideal retention of the cerebrospinal fluid. In many cases, use of contrast medium added no change to the CT picture. Cerebral angiography is necessary for definite diagnosis of the disease. Chronic subdural hematoma gives more varieties of findings than other intracranial hematomas. However, if the film is very carefully read, CT is still useful for diagnosing this disease in spite of initially remarked difficulties. (Ueda, J.)

  12. Efficacy and mucosal toxicity of concomitant chemo-radiotherapy in patients with locally-advanced squamous cell carcinoma of the head-and-neck in the light of a novel mathematical model.

    Science.gov (United States)

    Strigari, Lidia; Pinnarò, Paola; Carlini, Paolo; Torino, Francesco; Strolin, Silvia; Minosse, Silvia; Sanguineti, Giuseppe; Benassi, Marcello

    2016-06-01

    In the last several decades, combined radiotherapy (RT) and chemotherapy (CT) have been recognized as feasible in locally-advanced-squamous-cell-carcinoma of the head-and-neck (LA-HNSCC). Several meta-analyses identified concurrent RT+CT (CRT) most likely effective approach respect to RT-alone. However, radiobiological models comparing different chemotherapeutic schedules against delivered RT fractionation schedule for overall survival and toxicity are still needed. Based on 9 randomized trials (2785 patients), radiobiological models and multivariate logistic regression model were used to derive dose-response curves and estimate the 5-year-overall survival (OS) and ≥G3 acute mucositis rate of CRT or RT-alone. Equivalent dose at 2 Gy/fraction (EQD2) was calculated using the linear quadratic model. The effect of CRT schedules, considering the CT type and its administration schedule and the HPV status of tumors were estimated using the univariate/multivariate logistic regression. The multivariate logistic regression model for 5y-OS indicated EQD2 and the type of CT, the chemo-sensitization fraction and the HPV status significant prognostic factors, while for toxicity both EQD2 and the concomitant administration of 5-fluorouracil (5Fu) resulted as significant prognostic factors. Combined schedules cisplatin (DDP)+/-5Fu+RT produced the higher OS compared with combined carboplatin+/-5Fu+RT or RT-alone. The concomitant administration of Fu and schedule with high EQD2 increase the rate of observed ≥G3 acute mucositis. Multivariate logistic regression models can be used to predict CRT effect in terms of OS and ≥G3-mucositis, contributing to the identification of novel treatment schedules. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  13. Updates in Head and Neck Reconstruction.

    Science.gov (United States)

    Largo, Rene D; Garvey, Patrick B

    2018-02-01

    After reading this article, the participant should be able to: 1. Have a basic understanding of virtual planning, rapid prototype modeling, three-dimensional printing, and computer-assisted design and manufacture. 2. Understand the principles of combining virtual planning and vascular mapping. 3. Understand principles of flap choice and design in preoperative planning of free osteocutaneous flaps in mandible and midface reconstruction. 4. Discuss advantages and disadvantages of computer-assisted design and manufacture in reconstruction of advanced oncologic mandible and midface defects. Virtual planning and rapid prototype modeling are increasingly used in head and neck reconstruction with the aim of achieving superior surgical outcomes in functionally and aesthetically critical areas of the head and neck compared with conventional reconstruction. The reconstructive surgeon must be able to understand this rapidly-advancing technology, along with its advantages and disadvantages. There is no limit to the degree to which patient-specific data may be integrated into the virtual planning process. For example, vascular mapping can be incorporated into virtual planning of mandible or midface reconstruction. Representative mandible and midface cases are presented to illustrate the process of virtual planning. Although virtual planning has become helpful in head and neck reconstruction, its routine use may be limited by logistic challenges, increased acquisition costs, and limited flexibility for intraoperative modifications. Nevertheless, the authors believe that the superior functional and aesthetic results realized with virtual planning outweigh the limitations.

  14. 76 FR 31223 - Special Conditions: Bombardier Model BD-700-1A10 and BD-700-1A11 Airplanes, Head-up Display (HUD...

    Science.gov (United States)

    2011-05-31

    .... Per Type Certificate Data Sheet (TCDS) T00003NY, those aircraft models are known under the marketing...., conformal) to the external scene. In addition, the SVS image and the HUD symbols--when considered singly or... external scene. In such cases, these symbols may be displayed but with an altered appearance that makes the...

  15. TH-E-BRF-09: Gaussian Mixture Model Analysis of Radiation-Induced Parotid-Gland Injury: An Ultrasound Study of Acute and Late Xerostomia in Head-And-Neck Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, T [Department of Radiation Oncology and Winship Cancer Institute, Emory Univ, Atlanta, GA (United States); Yu, D; Beitler, J; Curran, W; Yang, X [Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA (United States); Tridandapani, S [Department of Radiology and Imaging Sciences and Winship Cancer Institute, Emory University, Atlanta, GA (United States); Bruner, D [School of Nursing and Winship Cancer Institute, Emory Univesity, Atlanta, GA (United States)

    2014-06-15

    Purpose: Xerostomia (dry mouth), secondary to parotid-gland injury, is a distressing side-effect in head-and-neck radiotherapy (RT). This study's purpose is to develop a novel ultrasound technique to quantitatively evaluate post-RT parotid-gland injury. Methods: Recent ultrasound studies have shown that healthy parotid glands exhibit homogeneous echotexture, whereas post-RT parotid glands are often heterogeneous, with multiple hypoechoic (inflammation) or hyperechoic (fibrosis) regions. We propose to use a Gaussian mixture model to analyze the ultrasonic echo-histogram of the parotid glands. An IRB-approved clinical study was conducted: (1) control-group: 13 healthy-volunteers, served as the control; (2) acutetoxicity group − 20 patients (mean age: 62.5 ± 8.9 years, follow-up: 2.0±0.8 months); and (3) late-toxicity group − 18 patients (mean age: 60.7 ± 7.3 years, follow-up: 20.1±10.4 months). All patients experienced RTOG grade 1 or 2 salivary-gland toxicity. Each participant underwent an ultrasound scan (10 MHz) of the bilateral parotid glands. An echo-intensity histogram was derived for each parotid and a Gaussian mixture model was used to fit the histogram using expectation maximization (EM) algorithm. The quality of the fitting was evaluated with the R-squared value. Results: (1) Controlgroup: all parotid glands fitted well with one Gaussian component, with a mean intensity of 79.8±4.9 (R-squared>0.96). (2) Acute-toxicity group: 37 of the 40 post-RT parotid glands fitted well with two Gaussian components, with a mean intensity of 42.9±7.4, 73.3±12.2 (R-squared>0.95). (3) Latetoxicity group: 32 of the 36 post-RT parotid fitted well with 3 Gaussian components, with mean intensities of 49.7±7.6, 77.2±8.7, and 118.6±11.8 (R-squared>0.98). Conclusion: RT-associated parotid-gland injury is common in head-and-neck RT, but challenging to assess. This work has demonstrated that the Gaussian mixture model of the echo-histogram could quantify acute and

  16. Head and Neck Cancer

    International Nuclear Information System (INIS)

    Tomita, Toshiki; Imanishi, Yorihisa

    2008-01-01

    The limitation of concurrent chemo-radiotherapy (CCRT) in head and neck cancer (HNC) as the primary treatment is described based on recent findings. Limits in the application/indication involve factors of age, performance status (PS) and renal function. The first is that, as deaths in >71 years old patients are derived from other causes (41%) than HNC, CCRT is only useful for younger population; the second, patients with PS 0-1 or Karnofsky performance score >60-70 can be indicated; and third, contraindicated are those with creatinine clearance (CCr) <60 mL/min as the key drug cisplatin in CCRT has a high renal toxicity. It should be recognized that completion rates of chemotherapy and RT are as low as 66-85% and 84-92%, respectively, in CCRT. CCRT has such limiting adverse events as mucitis, dry mouth, dysohagia, weight loss, neutropenia, sepsis, etc., which are most important in CCRT application. CCRT is recommended for the primary cancers of larynx and hypopharynx because they are significantly better conserved than middle pharyngeal, oral and upper jaw cancers. Evidence of CCRT is poor for cancers in paranasal sinuses. Planned neck dissection (PND) is for the cervical metastatic lymph nodes and conducted 6-12 weeks after CCRT regardless to its outcome. In fluorodeoxyglucose-positron emission tomography (FDG-PET) negative cases, PND can be omitted. Necessity of PND is possibly inversely proportional to CCRT intensity performed. For control of remote metastasis, CCRT has obvious limits and inductive chemotherapy before it is currently considered. Salvage surgery post CCRT does not always yield a relief because of complication. Patients with advanced laryngeal cancer can be selected either to surgery or CCRT depending on results of the inductive chemotherapy. To predict the sensitivity to CCRT, some biomarkers like HPV, EGFR and VEGF have been suggested to be useful by retrospective studies. Understanding the limitation is as important as knowing the usefulness in

  17. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... a CD or uploaded to a digital cloud server. Currently, MRI is the most sensitive imaging test ... Brain Tumor Treatment Magnetic Resonance Imaging (MRI) Safety Alzheimer's Disease Head Injury Brain Tumors Images related to Magnetic ...

  18. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... or cause problems during an MRI exam. Nephrogenic systemic fibrosis is currently a recognized, but rare, complication ... page Additional Information and Resources RTAnswers.org : Radiation Therapy for Brain Tumors Radiation Therapy for Head and ...

  19. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... be present in your body due to prior accidents. Foreign bodies near and especially lodged in the ... of page Additional Information and Resources RTAnswers.org : Radiation Therapy for Brain Tumors Radiation Therapy for Head and ...

  20. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... images and send a signed report to your primary care or referring physician, who will share the ... Tumor Treatment Magnetic Resonance Imaging (MRI) Safety Alzheimer's Disease Head Injury Brain Tumors Images related to Magnetic ...

  1. Zero torque gear head wrench

    Science.gov (United States)

    Mcdougal, A. R.; Norman, R. M. (Inventor)

    1976-01-01

    A gear head wrench particularly suited for use in applying torque to bolts without transferring torsional stress to bolt-receiving structures is introduced. The wrench is characterized by a coupling including a socket, for connecting a bolt head with a torque multiplying gear train, provided within a housing having an annulus concentrically related to the socket and adapted to be coupled with a spacer interposed between the bolt head and the juxtaposed surface of the bolt-receiving structure for applying a balancing counter-torque to the spacer as torque is applied to the bolt head whereby the bolt-receiving structure is substantially isolated from torsional stress. As a result of the foregoing, the operator of the wrench is substantially isolated from any forces which may be imposed.

  2. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... Radiation Therapy for Head and Neck Cancer Others : American Stroke Association National Stroke Association top of page ... and is further reviewed by committees from the American College of Radiology (ACR) and the Radiological Society ...

  3. Head, Neck, and Oral Cancer

    Medline Plus

    Full Text Available ... Oral Surgeries Facial Cosmetic Surgery Facial Injury / Trauma Surgery Obstructive Sleep Apnea (OSA) Oral, Head and Neck Pathology TMJ and Facial Pain Wisdom Teeth Management Procedures Anesthesia Anesthesia Oral and maxillofacial surgeons are ...

  4. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... of the head uses a powerful magnetic field, radio waves and a computer to produce detailed pictures of ... of the body being imaged, send and receive radio waves, producing signals that are detected by the coils. ...

  5. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... page What does the equipment look like? The traditional MRI unit is a large cylinder-shaped tube ... page Additional Information and Resources RTAnswers.org : Radiation Therapy for Brain Tumors Radiation Therapy for Head and ...

  6. Head, Neck, and Oral Cancer

    Medline Plus

    Full Text Available ... Other Oral Surgeries Facial Cosmetic Surgery Facial Injury / Trauma Surgery Obstructive Sleep Apnea (OSA) Oral, Head and Neck Pathology TMJ and Facial Pain Wisdom Teeth Management Procedures Anesthesia Anesthesia Oral and maxillofacial surgeons ...

  7. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... or headphones during the exam. MRI scanners are air-conditioned and well-lit. Music may be played ... the limitations of MRI of the Head? High-quality images are assured only if you are able ...

  8. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... Videos About Us News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic ... determine the presence of certain diseases. The images can then be examined on a computer monitor, transmitted ...

  9. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... it may cause some medical devices to malfunction. Most orthopedic implants pose no risk, but you should ... a digital cloud server. Currently, MRI is the most sensitive imaging test of the head (particularly the ...

  10. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... practice. top of page What are some common uses of the procedure? MR imaging of the head ... very early stage by mapping the motion of water molecules in the tissue. This water motion, known ...

  11. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... the head (particularly the brain) in routine clinical practice. top of page What are some common uses ... medical imaging or radiation oncology provider in your community, you can search the ACR-accredited facilities database . ...

  12. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... practice. top of page What are some common uses of the procedure? MR imaging of the head ... Society of Urogenital Radiology note that the available data suggest that it is safe to continue breastfeeding ...

  13. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... MRI typically costs more and may take more time to perform than other imaging modalities. top of page Additional Information and Resources RTAnswers.org : Radiation Therapy for Brain Tumors Radiation Therapy for Head and Neck Cancer ...

  14. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... practice. top of page What are some common uses of the procedure? MR imaging of the head ... their usual alignment, they emit different amounts of energy that vary according to the type of body ...

  15. Head, Neck, and Oral Cancer

    Medline Plus

    Full Text Available ... can also invite bacteria that lead to gum disease. Click here to find out more. Who We ... Injury / Trauma Surgery Obstructive Sleep Apnea (OSA) Oral, Head and Neck Pathology TMJ ...

  16. Head, Neck, and Oral Cancer

    Medline Plus

    Full Text Available ... teeth or become infected. It can also invite bacteria that lead to gum disease. Click here to find out ... and surgically treating cancer of the head, neck and mouth. The Oral Cancer Foundation estimates that close to ...

  17. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... practice. top of page What are some common uses of the procedure? MR imaging of the head ... gadolinium contrast, it may still be possible to use it after appropriate pre-medication. Patient consent will ...

  18. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... the same effect. A very irregular heartbeat may affect the quality of images obtained using techniques that ... Information and Resources RTAnswers.org : Radiation Therapy for Brain Tumors Radiation Therapy for Head and Neck Cancer ...

  19. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... a computer to produce detailed pictures of the brain and other cranial structures that are clearer and ... sensitive imaging test of the head (particularly the brain) in routine clinical practice. top of page What ...

  20. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... is not harmful, but it may cause some medical devices to malfunction. Most orthopedic implants pose no ... Head? Magnetic resonance imaging (MRI) is a noninvasive medical test that physicians use to diagnose medical conditions. ...

  1. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... and a computer to produce detailed pictures of the brain and other cranial structures that are clearer and ... most sensitive imaging test of the head (particularly the brain) in routine clinical practice. top of page What ...

  2. Heater head for stirling engine

    Science.gov (United States)

    Corey, John A.

    1985-07-09

    A monolithic heater head assembly which augments cast fins with ceramic inserts which narrow the flow of combustion gas and obtains high thermal effectiveness with the assembly including an improved flange design which gives greater durability and reduced conduction loss.

  3. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... ports artificial limbs or metallic joint prostheses implanted nerve stimulators metal pins, screws, plates, stents or surgical ... Magnetic Resonance Imaging (MRI) Safety Alzheimer's Disease Head Injury Brain Tumors Images related to Magnetic Resonance Imaging ( ...

  4. New Russian science head named

    CERN Multimedia

    Levitin, C

    2000-01-01

    Ilya Klebanov, a deputy prime minister, has been appointed the country's new head of industrial and scientific policy. He will control the new Ministry for Industry, Science and Technologies (4 paragraphs).

  5. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... practice. top of page What are some common uses of the procedure? MR imaging of the head ... is done because a potential abnormality needs further evaluation with additional views or a special imaging technique. ...

  6. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... of the head uses a powerful magnetic field, radio waves and a computer to produce detailed pictures ... medical conditions. MRI uses a powerful magnetic field, radio frequency pulses and a computer to produce detailed ...

  7. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ... page Additional Information and Resources RTAnswers.org : Radiation Therapy for Brain Tumors Radiation Therapy for Head and ...

  8. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... medically necessary. MRI may not always distinguish between cancer tissue and fluid, known as edema . MRI typically ... Brain Tumors Radiation Therapy for Head and Neck Cancer Others : American Stroke Association National Stroke Association top ...

  9. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... let the radiologist know about them. Parents or family members who accompany patients into the scanning room ... Tumor Treatment Magnetic Resonance Imaging (MRI) Safety Alzheimer's Disease Head Injury Brain Tumors Images related to Magnetic ...

  10. Head, Neck, and Oral Cancer

    Medline Plus

    Full Text Available ... disorders are not uncommon. Individuals with a TMJ disorder may experience a variety of symptoms, such as earaches, ... Obstructive Sleep Apnea (OSA) Oral, Head and Neck Pathology TMJ ...

  11. Preventing head injuries in children

    Science.gov (United States)

    ... to keep their children from getting head injuries. Car Safety Your child should wear a seatbelt at ... local sporting goods store, sports facility, or bike shop will be able to help make certain the ...

  12. Head, Neck, and Oral Cancer

    Medline Plus

    Full Text Available ... the head, neck and mouth. The Oral Cancer Foundation estimates that close to 42,000 Americans will ... cheek out to see its inside surface as well as the back of the gums Pull out ...

  13. Head, Neck, and Oral Cancer

    Medline Plus

    Full Text Available ... can also invite bacteria that lead to gum disease. Click here to find out more. Who We ... can also invite bacteria that lead to gum disease. Click here to find out more. Oral, Head ...

  14. Driver head pose tracking with thermal camera

    Science.gov (United States)

    Bole, S.; Fournier, C.; Lavergne, C.; Druart, G.; Lépine, T.

    2016-09-01

    Head pose can be seen as a coarse estimation of gaze direction. In automotive industry, knowledge about gaze direction could optimize Human-Machine Interface (HMI) and Advanced Driver Assistance Systems (ADAS). Pose estimation systems are often based on camera when applications have to be contactless. In this paper, we explore uncooled thermal imagery (8-14μm) for its intrinsic night vision capabilities and for its invariance versus lighting variations. Two methods are implemented and compared, both are aided by a 3D model of the head. The 3D model, mapped with thermal texture, allows to synthesize a base of 2D projected models, differently oriented and labeled in yaw and pitch. The first method is based on keypoints. Keypoints of models are matched with those of the query image. These sets of matchings, aided with the 3D shape of the model, allow to estimate 3D pose. The second method is a global appearance approach. Among all 2D models of the base, algorithm searches the one which is the closest to the query image thanks to a weighted least squares difference.

  15. CTOD-based acceptance criteria for heat exchanger head staybolts

    International Nuclear Information System (INIS)

    Lam, P.S.; Sindelar, R.L.; Barnes, D.M.; Awadalla, N.G.

    1992-01-01

    The primary coolant piping system of the Savannah River Site (SRS) reactors contains twelve heat exchangers to remove the waste heat from the nuclear materials production. A large break at the inlet or outlet heads of the heat exchangers would occur if the restraint members of the heads become inactive. The heat exchanger head is attached to the tubesheet by 84 staybolts. The structural integrity of the heads is demonstrated by showing the redundant capacity of the staybolts to restrain the head at design conditions and under seismic loadings. The beat exchanger head is analyzed with a three- dimensional finite element model. The restraint provided by the staybolts is evaluated for several postulated cases of inactive or missing staybolts, that is, bolts that have a flaw exceeding the ultrasonic testing (UT) threshold depth of 25% of the bolt diameter. A limit of 6 inactive staybolts is reached with a fracture criterion based on the maximum allowable local displacement at the active staybolts which corresponds to the crack tip opening displacement (CTOD) of 0.032 inches. An acceptance criteria methodology has been developed to disposition flaws reported in the staybolt inspections while ensuring adequate restraint capacity of the staybolts to maintain integrity of the heat exchanger heads against collapse. The methodology includes an approach for the baseline and periodic inspections of the staybolts. A total of up to 6 staybolts, reported as containing flaws with depths at or exceeding 25% would be acceptable in the heat exchanger

  16. Interpersonal Coordination of Head Motion in Distressed Couples

    Science.gov (United States)

    Hammal, Zakia; Cohn, Jeffrey F.; George, David T.

    2015-01-01

    In automatic emotional expression analysis, head motion has been considered mostly a nuisance variable, something to control when extracting features for action unit or expression detection. As an initial step toward understanding the contribution of head motion to emotion communication, we investigated the interpersonal coordination of rigid head motion in intimate couples with a history of interpersonal violence. Episodes of conflict and non-conflict were elicited in dyadic interaction tasks and validated using linguistic criteria. Head motion parameters were analyzed using Student’s paired t-tests; actor-partner analyses to model mutual influence within couples; and windowed cross-correlation to reveal dynamics of change in direction of influence over time. Partners’ RMS angular displacement for yaw and RMS angular velocity for pitch and yaw each demonstrated strong mutual influence between partners. Partners’ RMS angular displacement for pitch was higher during conflict. In both conflict and non-conflict, head angular displacement and angular velocity for pitch and yaw were strongly correlated, with frequent shifts in lead-lag relationships. The overall amount of coordination between partners’ head movement was more highly correlated during non-conflict compared with conflict interaction. While conflict increased head motion, it served to attenuate interpersonal coordination. PMID:26167256

  17. Automatic skull segmentation from MR images for realistic volume conductor models of the head: Assessment of the state-of-the-art

    DEFF Research Database (Denmark)

    Nielsen, Jesper Duemose; Madsen, Kristoffer Hougaard; Puonti, Oula

    2018-01-01

    three methods for skull segmentation, namely FSL BET2, the unified segmentation routine of SPM12 with extended spatial tissue priors, and the skullfinder tool of BrainSuite. To our knowledge, this study is the first to rigorously assess the accuracy of these state-of-the-art tools by comparison with CT...... models based on tetrahedral meshes, which are distributed as part of the open-source software package SimNIBS for field calculations for transcranial brain stimulation....

  18. Quantitative assessment of the morphology of the pig's head used as a model in surgical experimentation. Part 1: Methods of Measurements.

    Science.gov (United States)

    Farkas, L G; Munro, I R; Vanderby, B M

    1976-01-01

    Thirty-two surface measurements were described for assessment of the effect of complex surgical operations on the skeleton of the face in pigs. The methods of measurements imitate those of anthropometry. The surface measurements can complement cephalometry with data about the changes in the soft tissue and thus improve the documentation of the effect of surgery. This paper can help in the evaluation of complicated osteotomy procedures using the pig as the animal model, for facial reconstruction research in humans. PMID:1000401

  19. Penerapan Model Pembelajaran Kooperatif Tipe Numbered Heads Together (Nht) Untuk Meningkatkan Hasil Belajar IPA Siswa Kelas IV Sdn 009 Binio Jaya Kecamatan Kelayang

    OpenAIRE

    ', Lasmita; Marhadi, Hendri; Noviana, Eddy

    2017-01-01

    This study aimed purpose of this research is to improve learning outcomes IPA students class fourth of SDN 009 Binio Jaya Kecamatan Kelayang by applying the learning model NHT. The subjects were students of class IV consisting 24 students consisting of 13 male students and 11 female students. This type of research is the Classroom Action Research (PTK), which comprises two cycles (4 meetings). Based on the research activities of teachers in the first cycle-one meetings to gain success 58.33% ...

  20. Assessment of thermal effects in a model of the human head implanted with a wireless active microvalve for the treatment of glaucoma creating a filtering bleb

    Science.gov (United States)

    Schaumburg, F.; Guarnieri, F. A.

    2017-05-01

    A 3D anatomical computational model is developed to assess thermal effects due to exposure to the electromagnetic field required to power a new investigational active implantable microvalve for the treatment of glaucoma. Such a device, located in the temporal superior eye quadrant, produces a filtering bleb, which is included in the geometry of the model, together with the relevant ocular structures. The electromagnetic field source—a planar coil—as well as the microvalve antenna and casing are also included. Exposure to the electromagnetic field source of an implanted and a non-implanted subject are simulated by solving a magnetic potential formulation, using the finite element method. The maximum SAR10 is reached in the eyebrow and remains within the limits suggested by the IEEE and ICNIRP standards. The anterior chamber, filtering bleb, iris and ciliary body are the ocular structures where more absorption occurs. The temperature rise distribution is also obtained by solving the bioheat equation with the finite element method. The numerical results are compared with the in vivo measurements obtained from four rabbits implanted with the microvalve and exposed to the electromagnetic field source.