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Sample records for optimal target placement

  1. Toward Optimal Target Placement for Neural Prosthetic Devices

    PubMed Central

    Cunningham, John P.; Yu, Byron M.; Gilja, Vikash; Ryu, Stephen I.; Shenoy, Krishna V.

    2008-01-01

    Neural prosthetic systems have been designed to estimate continuous reach trajectories (motor prostheses) and to predict discrete reach targets (communication prostheses). In the latter case, reach targets are typically decoded from neural spiking activity during an instructed delay period before the reach begins. Such systems use targets placed in radially symmetric geometries independent of the tuning properties of the neurons available. Here we seek to automate the target placement process and increase decode accuracy in communication prostheses by selecting target locations based on the neural population at hand. Motor prostheses that incorporate intended target information could also benefit from this consideration. We present an optimal target placement algorithm that approximately maximizes decode accuracy with respect to target locations. In simulated neural spiking data fit from two monkeys, the optimal target placement algorithm yielded statistically significant improvements up to 8 and 9% for two and sixteen targets, respectively. For four and eight targets, gains were more modest, as the target layouts found by the algorithm closely resembled the canonical layouts. We trained a monkey in this paradigm and tested the algorithm with experimental neural data to confirm some of the results found in simulation. In all, the algorithm can serve not only to create new target layouts that outperform canonical layouts, but it can also confirm or help select among multiple canonical layouts. The optimal target placement algorithm developed here is the first algorithm of its kind, and it should both improve decode accuracy and help automate target placement for neural prostheses. PMID:18829845

  2. Comparing the Selection and Placement of Best Management Practices in Improving Water Quality Using a Multiobjective Optimization and Targeting Method

    PubMed Central

    Chiang, Li-Chi; Chaubey, Indrajeet; Maringanti, Chetan; Huang, Tao

    2014-01-01

    Suites of Best Management Practices (BMPs) are usually selected to be economically and environmentally efficient in reducing nonpoint source (NPS) pollutants from agricultural areas in a watershed. The objective of this research was to compare the selection and placement of BMPs in a pasture-dominated watershed using multiobjective optimization and targeting methods. Two objective functions were used in the optimization process, which minimize pollutant losses and the BMP placement areas. The optimization tool was an integration of a multi-objective genetic algorithm (GA) and a watershed model (Soil and Water Assessment Tool—SWAT). For the targeting method, an optimum BMP option was implemented in critical areas in the watershed that contribute the greatest pollutant losses. A total of 171 BMP combinations, which consist of grazing management, vegetated filter strips (VFS), and poultry litter applications were considered. The results showed that the optimization is less effective when vegetated filter strips (VFS) are not considered, and it requires much longer computation times than the targeting method to search for optimum BMPs. Although the targeting method is effective in selecting and placing an optimum BMP, larger areas are needed for BMP implementation to achieve the same pollutant reductions as the optimization method. PMID:24619160

  3. Targeted Pressure Management During CO2 Sequestration: Optimization of Well Placement and Brine Extraction

    DOE PAGESBeta

    Cihan, Abdullah; Birkholzer, Jens; Bianchi, Marco

    2014-12-31

    Large-scale pressure increases resulting from carbon dioxide (CO2) injection in the subsurface can potentially impact caprock integrity, induce reactivation of critically stressed faults, and drive CO2 or brine through conductive features into shallow groundwater. Pressure management involving the extraction of native fluids from storage formations can be used to minimize pressure increases while maximizing CO2 storage. However, brine extraction requires pumping, transportation, possibly treatment, and disposal of substantial volumes of extracted brackish or saline water, all of which can be technically challenging and expensive. This paper describes a constrained differential evolution (CDE) algorithm for optimal well placement and injection/ extractionmore » control with the goal of minimizing brine extraction while achieving predefined pressure contraints. The CDE methodology was tested for a simple optimization problem whose solution can be partially obtained with a gradient-based optimization methodology. The CDE successfully estimated the true global optimum for both extraction well location and extraction rate, needed for the test problem. A more complex example application of the developed strategy was also presented for a hypothetical CO2 storage scenario in a heterogeneous reservoir consisting of a critically stressed fault nearby an injection zone. Through the CDE optimization algorithm coupled to a numerical vertically-averaged reservoir model, we successfully estimated optimal rates and locations for CO2 injection and brine extraction wells while simultaneously satisfying multiple pressure buildup constraints to avoid fault activation and caprock fracturing. The study shows that the CDE methodology is a very promising tool to solve also other optimization problems related to GCS, such as reducing ‘Area of Review’, monitoring design, reducing risk of leakage and increasing storage capacity and trapping.« less

  4. Optimal landmarks selection and fiducial marker placement for minimal target registration error in image-guided neurosurgery

    NASA Astrophysics Data System (ADS)

    Shamir, Reuben R.; Joskowicz, Leo; Shoshan, Yigal

    2009-02-01

    We describe a new framework and method for the optimal selection of anatomical landmarks and optimal placement of fiducial markers in image-guided neurosurgery. The method allows the surgeon to optimally plan the markers locations on routine diagnostic images before preoperative imaging and to intraoperatively select the fiducial markers and the anatomical landmarks that minimize the Target Registration Error (TRE). The optimal fiducial marker configuration selection is performed by the surgeon on the diagnostic image following the target selection based on a visual Estimated TRE (E-TRE) map. The E-TRE map is automatically updated when the surgeon interactively adds and deletes candidate markers and targets. The method takes the guesswork out of the registration process, provides a reliable localization uncertainty error for navigation, and can reduce the localization error without additional imaging and hardware. Our clinical experiments on five patients who underwent brain surgery with a navigation system show that optimizing one marker location and the anatomical landmarks configuration reduces the average TRE from 4.7mm to 3.2mm, with a maximum improvement of 4mm. The reduction of the target registration error has the potential to support safer and more accurate minimally invasive neurosurgical procedures.

  5. Optimal Jammer Placement in Wireless Localization Systems

    NASA Astrophysics Data System (ADS)

    Gezici, Sinan; Bayram, Suat; Kurt, Mehmet Necip; Gholami, Mohammad Reza

    2016-09-01

    In this study, the optimal jammer placement problem is proposed and analyzed for wireless localization systems. In particular, the optimal location of a jammer node is obtained by maximizing the minimum of the Cramer-Rao lower bounds (CRLBs) for a number of target nodes under location related constraints for the jammer node. For scenarios with more than two target nodes, theoretical results are derived to specify conditions under which the jammer node is located as close to a certain target node as possible, or the optimal location of the jammer node is determined by two of the target nodes. Also, explicit expressions are provided for the optimal location of the jammer node in the presence of two target nodes. In addition, in the absence of distance constraints for the jammer node, it is proved, for scenarios with more than two target nodes, that the optimal jammer location lies on the convex hull formed by the locations of the target nodes and is determined by two or three of the target nodes, which have equalized CRLBs. Numerical examples are presented to provide illustrations of the theoretical results in different scenarios.

  6. Targeted Pressure Management During CO2 Sequestration: Optimization of Well Placement and Brine Extraction

    SciTech Connect

    Cihan, Abdullah; Birkholzer, Jens; Bianchi, Marco

    2014-12-31

    Large-scale pressure increases resulting from carbon dioxide (CO2) injection in the subsurface can potentially impact caprock integrity, induce reactivation of critically stressed faults, and drive CO2 or brine through conductive features into shallow groundwater. Pressure management involving the extraction of native fluids from storage formations can be used to minimize pressure increases while maximizing CO2 storage. However, brine extraction requires pumping, transportation, possibly treatment, and disposal of substantial volumes of extracted brackish or saline water, all of which can be technically challenging and expensive. This paper describes a constrained differential evolution (CDE) algorithm for optimal well placement and injection/ extraction control with the goal of minimizing brine extraction while achieving predefined pressure contraints. The CDE methodology was tested for a simple optimization problem whose solution can be partially obtained with a gradient-based optimization methodology. The CDE successfully estimated the true global optimum for both extraction well location and extraction rate, needed for the test problem. A more complex example application of the developed strategy was also presented for a hypothetical CO2 storage scenario in a heterogeneous reservoir consisting of a critically stressed fault nearby an injection zone. Through the CDE optimization algorithm coupled to a numerical vertically-averaged reservoir model, we successfully estimated optimal rates and locations for CO2 injection and brine extraction wells while simultaneously satisfying multiple pressure buildup constraints to avoid fault activation and caprock fracturing. The study shows that the CDE methodology is a very promising tool to solve also other optimization problems related to GCS, such as reducing ‘Area of Review’, monitoring design, reducing risk of leakage and increasing storage capacity and trapping.

  7. Optimal Sensor Placement for Multiple Target Positioning with Range-Only Measurements in Two-Dimensional Scenarios

    PubMed Central

    Moreno-Salinas, David; Pascoal, Antonio M.; Aranda, Joaquin

    2013-01-01

    The problem of determining the optimal geometric configuration of a sensor network that will maximize the range-related information available for multiple target positioning is of key importance in a multitude of application scenarios. In this paper, a set of sensors that measures the distances between the targets and each of the receivers is considered, assuming that the range measurements are corrupted by white Gaussian noise, in order to search for the formation that maximizes the accuracy of the target estimates. Using tools from estimation theory and convex optimization, the problem is converted into that of maximizing, by proper choice of the sensor positions, a convex combination of the logarithms of the determinants of the Fisher Information Matrices corresponding to each of the targets in order to determine the sensor configuration that yields the minimum possible covariance of any unbiased target estimator. Analytical and numerical solutions are well defined and it is shown that the optimal configuration of the sensors depends explicitly on the constraints imposed on the sensor configuration, the target positions, and the probabilistic distributions that define the prior uncertainty in each of the target positions. Simulation examples illustrate the key results derived. PMID:23959235

  8. Optimal sensor placement for multiple target positioning with range-only measurements in two-dimensional scenarios.

    PubMed

    Moreno-Salinas, David; Pascoal, Antonio M; Aranda, Joaquin

    2013-01-01

    The problem of determining the optimal geometric configuration of a sensor network that will maximize the range-related information available for multiple target positioning is of key importance in a multitude of application scenarios. In this paper, a set of sensors that measures the distances between the targets and each of the receivers is considered, assuming that the range measurements are corrupted by white Gaussian noise, in order to search for the formation that maximizes the accuracy of the target estimates. Using tools from estimation theory and convex optimization, the problem is converted into that of maximizing, by proper choice of the sensor positions, a convex combination of the logarithms of the determinants of the Fisher Information Matrices corresponding to each of the targets in order to determine the sensor configuration that yields the minimum possible covariance of any unbiased target estimator. Analytical and numerical solutions are well defined and it is shown that the optimal configuration of the sensors depends explicitly on the constraints imposed on the sensor configuration, the target positions, and the probabilistic distributions that define the prior uncertainty in each of the target positions. Simulation examples illustrate the key results derived. PMID:23959235

  9. Optimization Strategies for Sensor and Actuator Placement

    NASA Technical Reports Server (NTRS)

    Padula, Sharon L.; Kincaid, Rex K.

    1999-01-01

    This paper provides a survey of actuator and sensor placement problems from a wide range of engineering disciplines and a variety of applications. Combinatorial optimization methods are recommended as a means for identifying sets of actuators and sensors that maximize performance. Several sample applications from NASA Langley Research Center, such as active structural acoustic control, are covered in detail. Laboratory and flight tests of these applications indicate that actuator and sensor placement methods are effective and important. Lessons learned in solving these optimization problems can guide future research.

  10. Component placement optimization in the brain.

    PubMed

    Cherniak, C

    1994-04-01

    This computational neuroanatomy study evaluates how well some formalisms derived from combinatorial network optimization theory fit as models for brain structure. At multiple hierarchical levels--brain, ganglion, individual cell--physical placement of neural components appears consistent with a single, simple goal: minimize cost of connections among the components. The most dramatic instance of this "save wire" organizing principle is reported for adjacencies among ganglia in the nematode nervous system; among about 40,000,000 alternative layout orderings, the actual ganglion placement in fact requires the least total connection length. In addition, evidence supports a component placement optimization hypothesis for positioning of individual neurons in the nematode, and also for positioning of mammalian cortical areas. PMID:8158278

  11. Multi-Target Single Cycle Instrument Placement

    NASA Technical Reports Server (NTRS)

    Pedersen, Liam; Smith, David E.; Deans, Matthew; Sargent, Randy; Kunz, Clay; Lees, David; Rajagopalan, Srikanth; Bualat, Maria

    2005-01-01

    This presentation is about the robotic exploration of Mars using multiple targets command cycle, safe instrument placements, safe operation, and K9 Rover which has a 6 wheel steer rocket-bogey chassis (FIDO, MER), 70% MER size, 1.2 GHz Pentium M laptop running Linux OS, Odometry and compass/inclinometer, CLARAty architecture, 5 DOF manipulator w/CHAMP microscopic camera, SciCams, NavCams and HazCams.

  12. Optimizing Spacecraft Placement for Liaison Constellations

    NASA Technical Reports Server (NTRS)

    Chow, C. Channing; Villac, Benjamin F.; Lo, Martin W.

    2011-01-01

    A navigation and communications network is proposed to support an anticipated need for infrastructure in the Earth-Moon system. Periodic orbits will host the constellations while a novel, autonomous navigation strategy will guide the spacecraft along their path strictly based on satellite-to-satellite telemetry. In particular, this paper investigates the second stage of a larger constellation optimization scheme for multi-spacecraft systems. That is, following an initial orbit down-selection process, this analysis provides insights into the ancillary problem of spacecraft placement. Two case studies are presented that consider configurations of up to four spacecraft for a halo orbit and a cycler trajectory.

  13. Target Tracking, Approach, and Camera Handoff for Automated Instrument Placement

    NASA Technical Reports Server (NTRS)

    Bajracharya, Max; Diaz-Calderon, Antonio; Robinson, Matthew; Powell, Mark

    2005-01-01

    This paper describes the target designation, tracking, approach, and camera handoff technologies required to achieve accurate, single-command autonomous instrument placement for a planetary rover. It focuses on robust tracking integrated with obstacle avoidance during the approach phase, and image-based camera handoff to allow vision-based instrument placement. It also provides initial results from a complete system combining these technologies with rover base placement to maximize arm manipulability and image-based instrument placement.

  14. Endoscopic Gold Fiducial Marker Placement into the Bladder Wall to Optimize Radiotherapy Targeting for Bladder-Preserving Management of Muscle-Invasive Bladder Cancer: Feasibility and Initial Outcomes

    PubMed Central

    Garcia, Maurice M.; Gottschalk, Alexander R.; Brajtbord, Jonathan; Konety, Badrinath R.; Meng, Maxwell V.; Roach, Mack; Carroll, Peter R.

    2014-01-01

    Background and Purpose Bladder radiotherapy is a management option for carefully selected patients with muscle-invasive bladder cancer. However, the inability to visualize the tumor site during treatment and normal bladder movement limits targeting accuracy and increases collateral radiation. A means to accurately and reliably target the bladder during radiotherapy is needed. Materials and Methods Eighteen consecutive patients with muscle-invasive bladder cancer (T1–T4) elected bladder-preserving treatment with maximal transurethral resection (TUR), radiation and concurrent chemotherapy. All underwent endoscopic placement of 24-K gold fiducial markers modified with micro-tines (70 [2.9×0.9 mm.]; 19 [2.1×0.7 mm.) into healthy submucosa 5-10 mm. from the resection margin, using custom-made coaxial needles. Marker migration was assessed for with intra-op bladder-filling cystogram and measurement of distance between markers. Set-up error and marker retention through completion of radiotherapy was confirmed by on-table portal imaging. Results Between 1/2007 and 7/2012, a total of 89 markers (3–5 per tumor site) were placed into 18 patients of mean age 73.6 years. Two patients elected cystectomy before starting treatment; 16/18 completed chemo-radiotherapy. All (100%) markers were visible with all on-table (portal, cone-beam CT), fluoroscopy, plain-film, and CT-scan imaging. In two patients, 1 of 4 markers placed at the tumor site fell-out (voided) during the second half of radiotherapy. All other markers (80/82, 98%) were present through the end of radio-therapy. No intraoperative (e.g. uncontrolled bleeding, collateral injury) or post-operative complications (e.g. stone formation, urinary tract infection, post-TUR hematuria >48 hours) occurred. Use of micro-tined fiducial tumor-site markers afforded a 2 to 6-fold reduction in bladder-area targeted with high-dose radiation. Discussion Placement of the micro-tined fiducial markers into the bladder was feasible and

  15. Trajectory Optimization with Adaptive Deployable Entry and Placement Technology Architecture

    NASA Astrophysics Data System (ADS)

    Saranathan, H.; Saikia, S.; Grant, M. J.; Longuski, J. M.

    2014-06-01

    This paper compares the results of trajectory optimization for Adaptive Deployable Entry and Placement Technology (ADEPT) using different control methods. ADEPT addresses the limitations of current EDL technology in delivering heavy payloads to Mars.

  16. Optimal sensor placement in structural health monitoring using discrete optimization

    NASA Astrophysics Data System (ADS)

    Sun, Hao; Büyüköztürk, Oral

    2015-12-01

    The objective of optimal sensor placement (OSP) is to obtain a sensor layout that gives as much information of the dynamic system as possible in structural health monitoring (SHM). The process of OSP can be formulated as a discrete minimization (or maximization) problem with the sensor locations as the design variables, conditional on the constraint of a given sensor number. In this paper, we propose a discrete optimization scheme based on the artificial bee colony algorithm to solve the OSP problem after first transforming it into an integer optimization problem. A modal assurance criterion-oriented objective function is investigated to measure the utility of a sensor configuration in the optimization process based on the modal characteristics of a reduced order model. The reduced order model is obtained using an iterated improved reduced system technique. The constraint is handled by a penalty term added to the objective function. Three examples, including a 27 bar truss bridge, a 21-storey building at the MIT campus and the 610 m high Canton Tower, are investigated to test the applicability of the proposed algorithm to OSP. In addition, the proposed OSP algorithm is experimentally validated on a physical laboratory structure which is a three-story two-bay steel frame instrumented with triaxial accelerometers. Results indicate that the proposed method is efficient and can be potentially used in OSP in practical SHM.

  17. Computational issues in optimal tuning and placement of passive dampers

    NASA Technical Reports Server (NTRS)

    Chu, C. C.; Milman, M. H.

    1993-01-01

    The effectiveness of viscous elements in introducing damping in a structure is a function of several variables including their number, their location in the structure, and their physical properties. In this paper, the optimal damper placement and tuning problem is posed to optimize these variables. Both discrete and continuous optimization problems are formulated and solved corresponding, respectively, to the problems of placement of passive elements and to the tuning of their parameters. The paper particularly emphasizes the critical computational issues resulting from the optimization formulations. Numerical results involving a lightly damped testbed structure are presented.

  18. Targeting Error Simulator for Image-guided Prostate Needle Placement

    PubMed Central

    Lasso, Andras; Avni, Shachar; Fichtinger, Gabor

    2010-01-01

    Motivation Needle-based biopsy and local therapy of prostate cancer depend multimodal imaging for both target planning and needle guidance. The clinical process involves selection of target locations in a pre-operative image volume and registering these to an intra-operative volume. Registration inaccuracies inevitably lead to targeting error, a major clinical concern. The analysis of targeting error requires a large number of images with known ground truth, which has been infeasible even for the largest research centers. Methods We propose to generate realistic prostate imaging data in a controllable way, with known ground truth, by simulation of prostate size, shape, motion and deformation typically encountered in prostatic needle placement. This data is then used to evaluate a given registration algorithm, by testing its ability to reproduce ground truth contours, motions and deformations. The method builds on statistical shape atlas to generate large number of realistic prostate shapes and finite element modeling to generate high-fidelity deformations, while segmentation error is simulated by warping the ground truth data in specific prostate regions. Expected target registration error (TRE) is computed as a vector field. Results The simulator was configured to evaluate the TRE when using a surface-based rigid registration algorithm in a typical prostate biopsy targeting scenario. Simulator parameters, such as segmentation error and deformation, were determined by measurements in clinical images. Turnaround time for the full simulation of one test case was below 3 minutes. The simulator is customizable for testing, comparing, optimizing segmentation and registration methods and is independent of the imaging modalities used. PMID:21096275

  19. Optimizing robot placement for visit-point tasks

    SciTech Connect

    Hwang, Y.K.; Watterberg, P.A.

    1996-06-01

    We present a manipulator placement algorithm for minimizing the length of the manipulator motion performing a visit-point task such as spot welding. Given a set of points for the tool of a manipulator to visit, our algorithm finds the shortest robot motion required to visit the points from each possible base configuration. The base configurations resulting in the shortest motion is selected as the optimal robot placement. The shortest robot motion required for visiting multiple points from a given base configuration is computed using a variant of the traveling salesman algorithm in the robot joint space and a point-to-point path planner that plans collision free robot paths between two configurations. Our robot placement algorithm is expected to reduce the robot cycle time during visit- point tasks, as well as speeding up the robot set-up process when building a manufacturing line.

  20. Robust optimization of contaminant sensor placement for community water systems.

    SciTech Connect

    Konjevod, Goran; Carr, Robert D.; Greenberg, Harvey J.; Hart, William Eugene; Morrison, Tod; Phillips, Cynthia Ann; Lin, Henry; Lauer, Erik

    2004-09-01

    We present a series of related robust optimization models for placing sensors in municipal water networks to detect contaminants that are maliciously or accidentally injected.We formulate sensor placement problems as mixed-integer programs, for which the objective coefficients are not known with certainty. We consider a restricted absolute robustness criteria that is motivated by natural restrictions on the uncertain data, and we define three robust optimization models that differ in how the coefficients in the objective vary. Under one set of assumptions there exists a sensor placement that is optimal for all admissible realizations of the coefficients. Under other assumptions, we can apply sorting to solve each worst-case realization efficiently, or we can apply duality to integrate the worst-case outcome and have one integer program. The most difficult case is where the objective parameters are bilinear, and we prove its complexity is NP-hard even under simplifying assumptions. We consider a relaxation that provides an approximation, giving an overall guarantee of nearoptimality when used with branch-and-bound search. We present preliminary computational experiments that illustrate the computational complexity of solving these robust formulations on sensor placement applications.

  1. Simultaneous optimization of cryoprobe placement and thermal protocol for cryosurgery

    NASA Astrophysics Data System (ADS)

    Baissalov, R.; Sandison, G. A.; Reynolds, D.; Muldrew, K.

    2001-07-01

    We demonstrate that it is possible to simultaneously optimize multiple cryoprobe placements and their thermal protocol for one freeze-thaw cycle. A numerical optimization algorithm is used and three different forms of objective function are examined in terms of algorithm convergence rate, minimum value of the chosen objective function, temperature-volume histograms and isotherm distributions. The optimization results depend on the initial values of the variables, the form of the objective function, optimization goals and the mathematical method adopted for gradient calculation. The proposed optimization model offers significant advantages over the previously reported semi-empirical approach to conformal cryotherapy, such as the ability to handle an unlimited number of variables and eliminating the need for the user input between iterations, thereby reducing, if not removing, the subjectivity of cryosurgery treatment planning.

  2. Optimal placement of active elements in control augmented structural synthesis

    NASA Technical Reports Server (NTRS)

    Sepulveda, A. E.; Jin, I. M.; Schmit, L. A., Jr.

    1992-01-01

    A methodology for structural/control synthesis is presented in which the optimal location of active members is treated in terms of (0,1) variables. Structural member sizes, control gains and (0,1) placement variables are treated simultaneously as design variables. Optimization is carried out by generating and solving a sequence of explicit approximate problems using a branch and bound strategy. Intermediate design variable and intermediate response quantity concepts are used to enhance the quality of the approximate design problems. Numerical results for example problems are presented to illustrate the efficacy of the design procedure set forth.

  3. Discrete-Time ARMAv Model-Based Optimal Sensor Placement

    SciTech Connect

    Song Wei; Dyke, Shirley J.

    2008-07-08

    This paper concentrates on the optimal sensor placement problem in ambient vibration based structural health monitoring. More specifically, the paper examines the covariance of estimated parameters during system identification using auto-regressive and moving average vector (ARMAv) model. By utilizing the discrete-time steady state Kalman filter, this paper realizes the structure's finite element (FE) model under broad-band white noise excitations using an ARMAv model. Based on the asymptotic distribution of the parameter estimates of the ARMAv model, both a theoretical closed form and a numerical estimate form of the covariance of the estimates are obtained. Introducing the information entropy (differential entropy) measure, as well as various matrix norms, this paper attempts to find a reasonable measure to the uncertainties embedded in the ARMAv model estimates. Thus, it is possible to select the optimal sensor placement that would lead to the smallest uncertainties during the ARMAv identification process. Two numerical examples are provided to demonstrate the methodology and compare the sensor placement results upon various measures.

  4. Efficient Sensor Placement Optimization Using Gradient Descent and Probabilistic Coverage

    PubMed Central

    Akbarzadeh, Vahab; Lévesque, Julien-Charles; Gagné, Christian; Parizeau, Marc

    2014-01-01

    We are proposing an adaptation of the gradient descent method to optimize the position and orientation of sensors for the sensor placement problem. The novelty of the proposed method lies in the combination of gradient descent optimization with a realistic model, which considers both the topography of the environment and a set of sensors with directional probabilistic sensing. The performance of this approach is compared with two other black box optimization methods over area coverage and processing time. Results show that our proposed method produces competitive results on smaller maps and superior results on larger maps, while requiring much less computation than the other optimization methods to which it has been compared. PMID:25196164

  5. Use of coronary venous angioplasty to facilitate optimal placement of left ventricular lead during CRT.

    PubMed

    Osman, Faizel; Kundu, Suman; Tuan, Juin; Pathmanathan, Ravi K

    2009-02-01

    Cardiac resynchronization therapy (CRT) has become an accepted treatment for selected patients with drug-resistant heart failure. In some cases CRT implantation can be difficult, particularly optimal left ventricular stimulation through proper lead placement. Difficulties can arise from venous stenosis, atypical and tortuous coronary sinus anatomy, presence of venous valves, postoperative deformation, and absence of vessels in the target location. Various methods adapted from percutaneous coronary artery intervention can be applied to resolve these problems and ensure a good lead position. PMID:19170924

  6. Optimal PMU placement using topology transformation method in power systems.

    PubMed

    Rahman, Nadia H A; Zobaa, Ahmed F

    2016-09-01

    Optimal phasor measurement units (PMUs) placement involves the process of minimizing the number of PMUs needed while ensuring the entire power system completely observable. A power system is identified observable when the voltages of all buses in the power system are known. This paper proposes selection rules for topology transformation method that involves a merging process of zero-injection bus with one of its neighbors. The result from the merging process is influenced by the selection of bus selected to merge with the zero-injection bus. The proposed method will determine the best candidate bus to merge with zero-injection bus according to the three rules created in order to determine the minimum number of PMUs required for full observability of the power system. In addition, this paper also considered the case of power flow measurements. The problem is formulated as integer linear programming (ILP). The simulation for the proposed method is tested by using MATLAB for different IEEE bus systems. The explanation of the proposed method is demonstrated by using IEEE 14-bus system. The results obtained in this paper proved the effectiveness of the proposed method since the number of PMUs obtained is comparable with other available techniques. PMID:27489729

  7. Optimization of EUVL reticle thickness for image placement accuracy

    NASA Astrophysics Data System (ADS)

    Zheng, Liang; Mikkelson, Andrew R.; Abdo, Amr Y.; Engelstad, Roxann L.; Lovell, Edward G.; White, Thomas J.

    2003-12-01

    Extreme ultraviolet lithography (EUVL) is one of the leading candidates for next-generation lithography in the sub-65 nm regime. The International Technology Roadmap for Semiconductors proposes overlay error budgets of 18 nm and 13 nm for the 45 nm and 32 nm nodes, respectively. Full three-dimensional finite element (FE) models were developed to identify the optimal mask thickness to minimize image placement (IP) errors. Five thicknesses of the EUVL reticle have been investigated ranging from 2.3 mm to 9.0 mm. The mask fabrication process was simulated, as well as the e-beam mounting, pattern transfer, and exposure mounting, utilizing FE structural models. Out-of-plane distortions and in-plane distortions were tracked for each process step. Both electrostatic and 3-point mounts were considered for the e-beam tool and exposure tool. In this case, increasing the thickness of the reticle will reduce the magnitude of the distortions. The effect of varying the reticle thickness on chucking was also studied. FE models were utilized to predict how changing the reticle thickness would affect the overall clamping response. By decreasing the reticle thickness (and therefore the effective bending stiffness), the deformed reticle is easier to flatten during chucking. In addition, the thermomechanical response of the reticle during exposure was investigated for different reticle thicknesses. Since conduction to the chuck is the main heat dissipation mechanism, decreasing the reticle thickness results in more energy being conducted away from the reticle, which reduces the maximum temperature rise and the corresponding thermal distortion. The FE simulations illustrate the optimal thickness to keep IP errors within the allotted error budget as well as provide the necessary flatness during typical chucking procedures.

  8. A Framework for Optimizing the Placement of Tidal Turbines

    NASA Astrophysics Data System (ADS)

    Nelson, K. S.; Roberts, J.; Jones, C.; James, S. C.

    2013-12-01

    Power generation with marine hydrokinetic (MHK) current energy converters (CECs), often in the form of underwater turbines, is receiving growing global interest. Because of reasonable investment, maintenance, reliability, and environmental friendliness, this technology can contribute to national (and global) energy markets and is worthy of research investment. Furthermore, in remote areas, small-scale MHK energy from river, tidal, or ocean currents can provide a local power supply. However, little is known about the potential environmental effects of CEC operation in coastal embayments, estuaries, or rivers, or of the cumulative impacts of these devices on aquatic ecosystems over years or decades of operation. There is an urgent need for practical, accessible tools and peer-reviewed publications to help industry and regulators evaluate environmental impacts and mitigation measures, while establishing best sitting and design practices. Sandia National Laboratories (SNL) and Sea Engineering, Inc. (SEI) have investigated the potential environmental impacts and performance of individual tidal energy converters (TECs) in Cobscook Bay, ME; TECs are a subset of CECs that are specifically deployed in tidal channels. Cobscook Bay is the first deployment location of Ocean Renewable Power Company's (ORPC) TidGenTM unit. One unit is currently in place with four more to follow. Together, SNL and SEI built a coarse-grid, regional-scale model that included Cobscook Bay and all other landward embayments using the modeling platform SNL-EFDC. Within SNL-EFDC tidal turbines are represented using a unique set of momentum extraction, turbulence generation, and turbulence dissipation equations at TEC locations. The global model was then coupled to a local-scale model that was centered on the proposed TEC deployment locations. An optimization frame work was developed that used the refined model to determine optimal device placement locations that maximized array performance. Within the

  9. The Homogeneity of Optimal Sensor Placement Across Multiple Winged Insect Species

    NASA Astrophysics Data System (ADS)

    Jenkins, Abigail L.

    Taking inspiration from biology, control algorithms can be implemented to imitate the naturally occurring control systems present in nature. This research is primarily concerned with insect flight and optimal wing sensor placement. Many winged insects with halteres are equipped with mechanoreceptors termed campaniform sensilla. Although the exact information these receptors provide to the insect's nervous system is unknown, it is thought to have the capability of measuring inertial rotation forces. During flight, when the wing bends, the information measured by the campaniform sensilla is received by the central nervous system, and provides the insect necessary data to control flight. This research compares three insect species - the hawkmoth Manduca sexta, the honeybee Apis mellifera, and the fruit fly Drosophila melanogaster. Using an observability-based sensor placement algorithm, the optimal sensor placement for these three species is determined. Simulations resolve if this optimal sensor placement corresponds to the insect's campaniform sensilla, as well as if placement is homogeneous across species.

  10. Targeted versus standard bait station placement affects subterranean termite (Isoptera: Rhinotermitidae) infestation rates.

    PubMed

    Jones, Susan C

    2003-10-01

    A major challenge to termite baiting in soil habitats is the prolonged time that it may take for subterranean termites (Isoptera: Rhinotermitidae) to infest stations. The objective of this research study was to determine whether the location of food sources (Sentricon in-ground monitoring stations and wooden monitors) influences the likelihood of infestation by termites. In field trials conducted at 15 structures in central Ohio, standard placement of stations at 3-4.5 m intervals was compared with targeted placements based on evidence of termite activity indoors and outdoors as well as conducive moisture conditions. Termites infested significantly more targeted placements (70/374) than standard placements (35/372) around structures. At the targeted placement sites, termites infested more wooden monitors than Sentricon stations, but this was not statistically significant. This implies that placement, rather than cellulose composition, was the more important factor. Termites first infested stations/monitors an average of 38 d sooner at targeted sites than standard placement sites. This research indicates that evidence of termite activity indoors and outdoors should be a prime consideration when placing in-ground stations. PMID:14650527

  11. Effects of noise variance model on optimal feedback design and actuator placement

    NASA Technical Reports Server (NTRS)

    Ruan, Mifang; Choudhury, Ajit K.

    1994-01-01

    In optimal placement of actuators for stochastic systems, it is commonly assumed that the actuator noise variances are not related to the feedback matrix and the actuator locations. In this paper, we will discuss the limitation of that assumption and develop a more practical noise variance model. Various properties associated with optimal actuator placement under the assumption of this noise variance model are discovered through the analytical study of a second order system.

  12. Evaluating a Targeted Social Program When Placement Is Decentralized. Policy Research Working Papers No. 1945.

    ERIC Educational Resources Information Center

    Ravallion, Martin; Wodon, Quentin

    Assessment of welfare gains from a targeted social program can be seriously biased unless the endogeneity of program participation is addressed. Bias comes from two sources of placement endogeneity: the purposive targeting of geographic areas, and the targeting of individual recipients within selected areas. Partial decentralization of program…

  13. Optimized passive sonar placement to allow improved interdiction

    NASA Astrophysics Data System (ADS)

    Johnson, Bruce A.; Matthews, Cameron

    2016-05-01

    The Art Gallery Problem (AGP) is the name given to a constrained optimization problem meant to determine the maximum amount of sensor coverage while utilizing the minimum number of resources. The AGP is significant because a common issue among surveillance and interdiction systems is obtaining an understanding of the optimal position of sensors and weapons in advance of enemy combatant maneuvers. The implication that an optimal position for a sensor to observe an event or for a weapon to engage a target autonomously is usually very clear after the target has passed, but for autonomous systems the solution must at least be conjectured in advance for deployment purposes. This abstract applies the AGP as a means to solve where best to place underwater sensor nodes such that the amount of information acquired about a covered area is maximized while the number of resources used to gain that information is minimized. By phrasing the ISR/interdiction problem this way, the issue is addressed as an instance of the AGP. The AGP is a member of a set of computational problems designated as nondeterministic polynomial-time (NP)-hard. As a member of this set, the AGP shares its members' defining feature, namely that no one has proven that there exists a deterministic algorithm providing a computationally-tractable solution to the AGP within a finite amount of time. At best an algorithm meant to solve the AGP can asymptotically approach perfect coverage with minimal resource usage but providing perfect coverage would either break the minimal resource usage constraint or require an exponentially-growing amount of time. No perfectly-optimal solution yet exists to the AGP, however, approximately optimal solutions to the AGP can approach complete area or barrier coverage while simultaneously minimizing the number of sensors and weapons utilized. A minimal number of underwater sensor nodes deployed can greatly increase the Mean Time Between Operational Failure (MTBOF) and logistical

  14. Application of fuzzy logic to optimize placement of an acquisition, tracking, and pointing experiment

    NASA Astrophysics Data System (ADS)

    Bukley, Jerry

    The experiment is comprised of a 115,000 cubic meter helium balloon which lifts a 2,900 kg Acquisition, Tracking and Pointing (ATP) experiment package to an altitude of 26 km. The Phillips Laboratory High Altitude Balloon Experiment (HABE) has been developed as a cost-effective means of testing satellite ATP technologies in an environment similar to space. A major advantage of the concept is the flexibility in placement and timing afforded a balloon over a satellite. This flexibility allows HABE to engage targets-of-opportunity launched from the domestic ranges without requiring a dedicated or closely coordinated launch time. The placement of HABE is optimized to maximize active track time. A routine was developed to raster scan the mathematical model of a flight corridor while accumulating the intervals of continuous engagement that satisfy a list of ten rules. Although successful, this method is unable to place priorities or make trades based on the relative importance of the rules. The use of fuzzy logic in the form of approximate reasoning to evaluate the rules, while also considering goals, enables key qualitative considerations to be factored into the overall evaluation. This paper describes the application of fuzzy logic to data analysis and compares the results to conventional Boolean techniques.

  15. Optimized baffle and aperture placement in neutral beamlines

    NASA Astrophysics Data System (ADS)

    Stone, R.; Duffy, T.; Vetrovec, J.

    1983-11-01

    Most neutral beamlines contain an iron-core ion-bending magnet that requires shielding between the end of the neutralizer and this magnet. This shielding allows the gas pressure to drop prior to the beam entering the magnet and therefore reduces beam losses in this drift region. The beam losses are reduced even further by eliminating the iron-core magnet and the magnetic shielding altogether. The required bending field is supplied by current coils without the iron poles. In addition, placement of the baffles and apertures affects the cold gas entering the plasma region and the losses in the neutral beam due to re-ionization. The placement of the baffles which, determine the amount of pumping in each chamber, and the apertures, which determine the beam loss were varied. A baffler/aperture configuration is for either minimum cold gas into the plasma region or minimum beam losses, but not both.

  16. Simultaneous optimization of loading pattern and burnable poison placement for PWRs

    SciTech Connect

    Alim, F.; Ivanov, K.; Yilmaz, S.

    2006-07-01

    To solve in-core fuel management optimization problem, GARCO-PSU (Genetic Algorithm Reactor Core Optimization - Pennsylvania State Univ.) is developed. This code is applicable for all types and geometry of PWR core structures with unlimited number of fuel assembly (FA) types in the inventory. For this reason an innovative genetic algorithm is developed with modifying the classical representation of the genotype. In-core fuel management heuristic rules are introduced into GARCO. The core re-load design optimization has two parts, loading pattern (LP) optimization and burnable poison (BP) placement optimization. These parts depend on each other, but it is difficult to solve the combined problem due to its large size. Separating the problem into two parts provides a practical way to solve the problem. However, the result of this method does not reflect the real optimal solution. GARCO-PSU achieves to solve LP optimization and BP placement optimization simultaneously in an efficient manner. (authors)

  17. Optimal placement of tuning masses on truss structures by genetic algorithms

    NASA Technical Reports Server (NTRS)

    Ponslet, Eric; Haftka, Raphael T.; Cudney, Harley H.

    1993-01-01

    Optimal placement of tuning masses, actuators and other peripherals on large space structures is a combinatorial optimization problem. This paper surveys several techniques for solving this problem. The genetic algorithm approach to the solution of the placement problem is described in detail. An example of minimizing the difference between the two lowest frequencies of a laboratory truss by adding tuning masses is used for demonstrating some of the advantages of genetic algorithms. The relative efficiencies of different codings are compared using the results of a large number of optimization runs.

  18. Robust optimal sensor placement for operational modal analysis based on maximum expected utility

    NASA Astrophysics Data System (ADS)

    Li, Binbin; Der Kiureghian, Armen

    2016-06-01

    Optimal sensor placement is essentially a decision problem under uncertainty. The maximum expected utility theory and a Bayesian linear model are used in this paper for robust sensor placement aimed at operational modal identification. To avoid nonlinear relations between modal parameters and measured responses, we choose to optimize the sensor locations relative to identifying modal responses. Since the modal responses contain all the information necessary to identify the modal parameters, the optimal sensor locations for modal response estimation provide at least a suboptimal solution for identification of modal parameters. First, a probabilistic model for sensor placement considering model uncertainty, load uncertainty and measurement error is proposed. The maximum expected utility theory is then applied with this model by considering utility functions based on three principles: quadratic loss, Shannon information, and K-L divergence. In addition, the prior covariance of modal responses under band-limited white-noise excitation is derived and the nearest Kronecker product approximation is employed to accelerate evaluation of the utility function. As demonstration and validation examples, sensor placements in a 16-degrees-of-freedom shear-type building and in Guangzhou TV Tower under ground motion and wind load are considered. Placements of individual displacement meter, velocimeter, accelerometer and placement of mixed sensors are illustrated.

  19. Adaptive sensor placement for target tracking in the presence of uncertainties

    NASA Astrophysics Data System (ADS)

    Punithakumar, Kumaradevan; Kirubarajan, Thiagalingam; Hernandez, Marcel L.

    2003-12-01

    Recently a general framework for sensor resource management, which has been shown to allow efficient and effective utilization of a multisensor system was introduced in5. The basis of this technique is to use the Posterior Cramer-Rao Lower Bound (PCRLB) to quantify and control the optimal achievable accuracy of target state estimation. In the current paper we extend this framework by addressing the issues of imperfect sensor placement and uncertain sensor movement (e.g., sensor drift). In contrast the previous work considered only the case where the sensor location is known exactly. The crucial consideration is then how these two forms of uncertainty affect the sensor management strategy. If unaccounted for, these uncertainties will render the output of the resource manager useless. We adjust the PCRLB to account for sensor location uncertainty, and we also allow for measurement origin uncertainty (missed target originated detections and false alarms). The work is motivated by the problem of tracking a submarine by adaptively deploying sonobuoys from a helicopter. Simulation results are presented to show the advantages of accounting for sensor location uncertainty within this focal domain of anti-submarine warfare. The same technique can be used for tracking using unattended ground sensors (UGS) or unmanned aerial vehicles (UAV).

  20. Adaptive sensor placement for target tracking in the presence of uncertainties

    NASA Astrophysics Data System (ADS)

    Punithakumar, Kumaradevan; Kirubarajan, Thiagalingam; Hernandez, Marcel L.

    2004-01-01

    Recently a general framework for sensor resource management, which has been shown to allow efficient and effective utilization of a multisensor system was introduced in5. The basis of this technique is to use the Posterior Cramer-Rao Lower Bound (PCRLB) to quantify and control the optimal achievable accuracy of target state estimation. In the current paper we extend this framework by addressing the issues of imperfect sensor placement and uncertain sensor movement (e.g., sensor drift). In contrast the previous work considered only the case where the sensor location is known exactly. The crucial consideration is then how these two forms of uncertainty affect the sensor management strategy. If unaccounted for, these uncertainties will render the output of the resource manager useless. We adjust the PCRLB to account for sensor location uncertainty, and we also allow for measurement origin uncertainty (missed target originated detections and false alarms). The work is motivated by the problem of tracking a submarine by adaptively deploying sonobuoys from a helicopter. Simulation results are presented to show the advantages of accounting for sensor location uncertainty within this focal domain of anti-submarine warfare. The same technique can be used for tracking using unattended ground sensors (UGS) or unmanned aerial vehicles (UAV).

  1. Optimal placement of actuators and sensors in control augmented structural optimization

    NASA Technical Reports Server (NTRS)

    Sepulveda, A. E.; Schmit, L. A., Jr.

    1990-01-01

    A control-augmented structural synthesis methodology is presented in which actuator and sensor placement is treated in terms of (0,1) variables. Structural member sizes and control variables are treated simultaneously as design variables. A multiobjective utopian approach is used to obtain a compromise solution for inherently conflicting objective functions such as strucutal mass control effort and number of actuators. Constraints are imposed on transient displacements, natural frequencies, actuator forces and dynamic stability as well as controllability and observability of the system. The combinatorial aspects of the mixed - (0,1) continuous variable design optimization problem are made tractable by combining approximation concepts with branch and bound techniques. Some numerical results for example problems are presented to illustrate the efficacy of the design procedure set forth.

  2. Optimization of actuator and sensor placement for on-orbit identification in large flexible spacecraft

    NASA Technical Reports Server (NTRS)

    Bergmann, Martin; Longman, Richard W.; Juang, Jer-Nan

    1990-01-01

    There has been considerable research on choosing actuator and sensor locations in large flexible spacecraft in order to optimize the controllability and observability of the system, or to maximize some objective function of control system performance. Future large flexible spacecraft may require on-orbit identification of the structure to tune the control system, because such tests cannot be performed in a one-g environment before launch. This indicates that the choice of actuator and sensor locations must serve a dual purpose, for control and for identification. This paper develops concepts for a degree of identifiability and studies placement of actuators and sensors on a free-free beam to optimize such objective functions. The results in this simple situation suggest that in free-free spacecraft structures in orbit, placement for control and placement for identification may often be consistent objectives rather than conflicting objectives.

  3. Optimal placement of magnets in Indus-2 storage ring

    NASA Astrophysics Data System (ADS)

    Riyasat, Husain; A, D. Ghodke; Singh, Gurnam

    2015-03-01

    In Indus-2, by optimizing the position of the magnetic elements, using the simulated annealing algorithm, at different locations in the ring with their field errors, the effects on beam parameters have been minimized. Closed orbit distortion and beta beat are considerably reduced by optimizing the dipole and quadrupole magnets positions in the ring. For the Indus-2 storage ring, sextupole optimization gives insignificant improvement in dynamic aperture with chromaticity-correcting sextupoles. The magnets have been placed in the ring with the optimized sequence and storage of the beam has been achieved at injection energy without energizing any corrector magnets. Magnet sorting has led to the easy beam current accumulation and the measurement of parameters such as closed orbit distortion, beta function, dispersion, dynamic aperture etc.

  4. Targeted Placement of Gold Nanoparticles on SWCNT Transistors Using Electrodeposition

    NASA Astrophysics Data System (ADS)

    Liu, Yian; Barbara, Paola; Paranjape, Makarand

    2013-03-01

    We present a simple in-situ electrochemical method to target the deposition of gold and other metallic nanoparticles along a single-walled carbon nanotube (SWCNT) field effect transistor (CNTFET). The transistors, fabricated on SiO2/Si substrates, are passivated by a thin layer of poly(methyl-methacrylate), or PMMA. Areas of the PMMA along the carbon nanotube are exposed using electron-beam lithography to target the locations where Au nanoparticles need to be placed. An appropriate potential difference is applied between an in-situ sacrificial gold electrode and the SWCNT, all immersed under a droplet of electrolyte solution. By adjusting the applied voltage and time of deposition, the size of the Au nanoparticle can be controlled from 10 nm to over 100 nm. This method provides better control and is much easier to carry out compared to other site-specific deposition techniques. Such decorated Au nanoparticle/CNTFET heterostructures will allow for a better understanding of single-electron transport behavior, as well as finding application in site-specific biomolecule anchoring for the development of highly sensitive and selective biosensors.

  5. Joint optimization of mixed regenerator placement and wavelength assignment for green translucent optical networks

    NASA Astrophysics Data System (ADS)

    Zhu, Zuqing; Zhong, Weida; Wan, Chuanqi

    2011-12-01

    We propose network design algorithms to minimize the power consumption of a translucent optical network with joined optimization of mixed regenerator placement and wavelength assignment. The performance of the algorithms is investigated with simulations in ring and grid network topologies. Simulation results indicate that the algorithms can effectively reduce the number of O/E/O 3R regenerators, leading to less power consumption on signal regeneration and green network design. Among the algorithms, the maximum segment length wavelength assignment(MSL-WA) approach further reduces regenerator numbers, with the cost of placement readjustments.

  6. OPTIMIZING BMP PLACEMENT AT WATERSHED-SCALE USING SUSTAIN

    EPA Science Inventory

    Watershed and stormwater managers need modeling tools to evaluate alternative plans for environmental quality restoration and protection needs in urban and developing areas. A watershed-scale decision-support system, based on cost optimization, provides an essential tool to suppo...

  7. Optimal Colostomy Placement in Spinal Cord Injury Patients.

    PubMed

    Xu, Jiashou; Dharmarajan, Sekhar; Johnson, Frank E

    2016-03-01

    Barring unusual circumstances, sigmoid colostomy is the optimal technique for management of defecation in spinal cord injury (SCI) patients. We sought to provide evidence that a sigmoid colostomy is not difficult to perform in SCI patients and has better long-term results. The St. Louis Department of Veterans Affairs has a Commission on Accreditation of Rehabilitation Facilities (CARF)-approved SCI Unit. We reviewed the operative notes on all SCI patients who received a colostomy for fecal management by three ASCRS-certified colorectal surgeons at the St. Louis Department of Veterans Affairs from January 1, 2007 to November 26, 2012. There were 27 operations for which the recorded indication for surgery suggested that the primary disorder was SCI. Fourteen had traumatic SCI of the thoracic and/or lumbar spine and were evaluable. Of these 14 patients, 12 had laparoscopic sigmoid colostomy and two had open sigmoid colostomy. We encountered one evaluable patient with a remarkably large amount of retroperitoneal bony debris who successfully underwent laparoscopic sigmoid colostomy. In conclusion, sigmoid colostomy is the consensus optimal procedure for fecal management in SCI patients. Laparoscopic procedures are preferred. Care providers should specify sigmoid colostomy when contacting a surgeon. PMID:27099066

  8. Optimal flow sensor placement on wastewater treatment plants.

    PubMed

    Villez, Kris; Vanrolleghem, Peter A; Corominas, Lluís

    2016-09-15

    Obtaining high quality data collected on wastewater treatment plants is gaining increasing attention in the wastewater engineering literature. Typical studies focus on recognition of faulty data with a given set of installed sensors on a wastewater treatment plant. Little attention is however given to how one can install sensors in such a way that fault detection and identification can be improved. In this work, we develop a method to obtain Pareto optimal sensor layouts in terms of cost, observability, and redundancy. Most importantly, the resulting method allows reducing the large set of possibilities to a minimal set of sensor layouts efficiently for any wastewater treatment plant on the basis of structural criteria only, with limited sensor information, and without prior data collection. In addition, the developed optimization scheme is fast. Practically important is that the number of sensors needed for both observability of all flows and redundancy of all flow sensors is only one more compared to the number of sensors needed for observability of all flows in the studied wastewater treatment plant configurations. PMID:27258618

  9. Optimal Sensor Placement for Leak Location in Water Distribution Networks Using Genetic Algorithms

    PubMed Central

    Casillas, Myrna V.; Puig, Vicenç; Garza-Castañón, Luis E.; Rosich, Albert

    2013-01-01

    This paper proposes a new sensor placement approach for leak location in water distribution networks (WDNs). The sensor placement problem is formulated as an integer optimization problem. The optimization criterion consists in minimizing the number of non-isolable leaks according to the isolability criteria introduced. Because of the large size and non-linear integer nature of the resulting optimization problem, genetic algorithms (GAs) are used as the solution approach. The obtained results are compared with a semi-exhaustive search method with higher computational effort, proving that GA allows one to find near-optimal solutions with less computational load. Moreover, three ways of increasing the robustness of the GA-based sensor placement method have been proposed using a time horizon analysis, a distance-based scoring and considering different leaks sizes. A great advantage of the proposed methodology is that it does not depend on the isolation method chosen by the user, as long as it is based on leak sensitivity analysis. Experiments in two networks allow us to evaluate the performance of the proposed approach. PMID:24193099

  10. Newtonian Imperialist Competitve Approach to Optimizing Observation of Multiple Target Points in Multisensor Surveillance Systems

    NASA Astrophysics Data System (ADS)

    Afghan-Toloee, A.; Heidari, A. A.; Joibari, Y.

    2013-09-01

    The problem of specifying the minimum number of sensors to deploy in a certain area to face multiple targets has been generally studied in the literatures. In this paper, we are arguing the multi-sensors deployment problem (MDP). The Multi-sensor placement problem can be clarified as minimizing the cost required to cover the multi target points in the area. We propose a more feasible method for the multi-sensor placement problem. Our method makes provision the high coverage of grid based placements while minimizing the cost as discovered in perimeter placement techniques. The NICA algorithm as improved ICA (Imperialist Competitive Algorithm) is used to decrease the performance time to explore an enough solution compared to other meta-heuristic schemes such as GA, PSO and ICA. A three dimensional area is used for clarify the multiple target and placement points, making provision x, y, and z computations in the observation algorithm. A structure of model for the multi-sensor placement problem is proposed: The problem is constructed as an optimization problem with the objective to minimize the cost while covering all multiple target points upon a given probability of observation tolerance.

  11. Optimal actuator and sensor placement in the linearized complex Ginzburg-Landau system

    NASA Astrophysics Data System (ADS)

    Chen, Kevin; Rowley, Clarence

    2010-11-01

    The linearized complex Ginzburg-Landau equation is a model for the evolution of small fluid perturbations, such as in a bluff body wake. We control this system by implementing actuators and sensors and designing an H2-optimal controller. We seek the optimal actuator and sensor placement that minimizes the H2 norm of the controlled system, from flow disturbances to a cost on the perturbation and input magnitude. We formulate the gradient of the H2 squared norm with respect to actuator and sensor positions, and iterate toward the optimal position. With a single actuator and sensor, it is optimal to place the actuator just upstream of the origin (e.g., the bluff body object) and the sensor just downstream. With multiple but an equal number of actuators and sensors, it is optimal to arrange them in pairs, placing actuators slightly upstream of sensors, and scattering pairs throughout the spatial domain. Global mode and Gramian analyses fail to predict the optimal placement; they produce H2 norms about five times higher than at the true optimum. A wave maker formulation is better able to guess an initial condition for the iterator.

  12. Optimal circumferential placement of cylindrical thermocouple probes for reduction of excitation forces

    SciTech Connect

    Cobb, E.C.; Cheu, T.C.; Hoffman, J. )

    1993-04-01

    This paper presents a design methodology to determine the optimal circumferential placement of cylindrical probes upstream of a turbine stage for reduced excitation forces. The potential flow forcing function generated by the probes is characterized by means of a Fourier analysis. A finite difference formulation is used to evaluate the sensitivity of the forcing function to the probe positions. An optimization scheme, based on the linear programming method, uses the sensitivity analysis results to reposition the probes such that the Fourier amplitudes of critical excitation orders are reduced. The results for a sample design situation are presented.

  13. Optimal placement of excitations and sensors for verification of large dynamical systems

    NASA Technical Reports Server (NTRS)

    Salama, M.; Rose, T.; Garba, J.

    1987-01-01

    The computationally difficult problem of the optimal placement of excitations and sensors to maximize the observed measurements is studied within the framework of combinatorial optimization, and is solved numerically using a variation of the simulated annealing heuristic algorithm. Results of numerical experiments including a square plate and a 960 degrees-of-freedom Control of Flexible Structure (COFS) truss structure, are presented. Though the algorithm produces suboptimal solutions, its generality and simplicity allow the treatment of complex dynamical systems which would otherwise be difficult to handle.

  14. A Bayesian approach to optimal sensor placement for structural health monitoring with application to active sensing

    NASA Astrophysics Data System (ADS)

    Flynn, Eric B.; Todd, Michael D.

    2010-05-01

    This paper introduces a novel approach for optimal sensor and/or actuator placement for structural health monitoring (SHM) applications. Starting from a general formulation of Bayes risk, we derive a global optimality criterion within a detection theory framework. The optimal configuration is then established as the one that minimizes the expected total presence of either type I or type II error during the damage detection process. While the approach is suitable for many sensing/actuation SHM processes, we focus on the example of active sensing using guided ultrasonic waves by implementing an appropriate statistical model of the wave propagation and feature extraction process. This example implements both pulse-echo and pitch-catch actuation schemes and takes into account line-of-site visibility and non-uniform damage probabilities over the monitored structure. The optimization space is searched using a genetic algorithm with a time-varying mutation rate. We provide three actuator/sensor placement test problems and discuss the optimal solutions generated by the algorithm.

  15. Placement of cells: Theory and solution of a quadratic 0/1 optimization problem

    NASA Astrophysics Data System (ADS)

    Weismantel, Robert

    1992-01-01

    The placement problem by design of electronic chips is studied in the framework of very large scale integration. Methods for modeling placement are presented, such as min-cut heuristics, simulated annealing, and a continuous quadratic optimization method based on relaxation. The 'sea of cells' concept was chosen and a quadratic 0/1 optimization problem was described with a graph theory formulation. Variations of the problem and existence of polynomial, epsilon approximative algorithms were discussed. The problem was solved with heuristic decomposition method, with 16 locations for each cell and with 9 locations for each cell. A dynamic decomposition process was also described and a linear Lagrange relaxation solution was proposed. The clustering problem was introduced to reduce magnitude order of placement problem. The r-clustering polytope was presented from a polyhedral point of view. Several classes of facets were described by inequalities, which combine nodes and branches in the following cases: roof dual and disjuncted stars, roof dual and a tree, roof dual and a star, and roof dual and a branch.

  16. Articulatory Placement for /t/, /d/, /k/ and /g/ Targets in School Age Children with Speech Disorders Associated with Cleft Palate

    ERIC Educational Resources Information Center

    Gibbon, Fiona; Ellis, Lucy; Crampin, Lisa

    2004-01-01

    This study used electropalatography (EPG) to identify place of articulation for lingual plosive targets /t/, /d/, /k/ and /g/ in the speech of 15 school age children with repaired cleft palate. Perceptual judgements indicated that all children had correct velar placement for /k/, /g/ targets, but /t/, /d/ targets were produced as errors involving…

  17. Optimized electrode placement along the channel of a Hall thruster for ion focusing

    SciTech Connect

    Qing, Shaowei; E, Peng; Xia, Guangqing; Tang, Ming-Chun; Duan, Ping

    2014-01-21

    An optimal placement of the segmented electrode for increasing the lifetime of the Aton-type Hall thruster, i.e., reducing the plume divergence, is demonstrated using a 2D3V fully kinetic Particle-in-Cell method. Segmented electrodes, embedded near the ionization region of non-segmented case and biased above anode potential, lead to an increased separation between the ionization and acceleration regions and the formation of an efficient acceleration electric field configuration as potential lens. Due to this electrode placement, the sheath near the ceramic walls of the acceleration region is collapsed and an excellent ion beam focusing is demonstrated. The potential contour pockets around the electrodes and the sheath collapse phenomenon are also discussed.

  18. Optimal multi-type sensor placement for response and excitation reconstruction

    NASA Astrophysics Data System (ADS)

    Zhang, C. D.; Xu, Y. L.

    2016-01-01

    The need to perform dynamic response reconstruction always arises as the measurement of structural response is often limited to a few locations, especially for a large civil structure. Besides, it is usually very difficult, if not impossible, to measure external excitations under the operation condition of a structure. This study presents an algorithm for optimal placement of multi-type sensors, including strain gauges, displacement transducers and accelerometers, for the best reconstruction of responses of key structural components where there are no sensors installed and the best estimation of external excitations acting on the structure at the same time. The algorithm is developed in the framework of Kalman filter with unknown excitation, in which minimum-variance unbiased estimates of the generalized state of the structure and the external excitations are obtained by virtue of limited sensor measurements. The structural responses of key locations without sensors can then be reconstructed with the estimated generalized state and excitation. The asymptotic stability feature of the filter is utilized for optimal sensor placement. The number and spatial location of the multi-type sensors are determined by adding the optimal sensor which gains the maximal reduction of the estimation error of reconstructed responses. For the given mode number in response reconstruction and the given locations of external excitations, the optimal multi-sensor placement achieved by the proposed method is independent of the type and time evolution of external excitation. A simply-supported overhanging steel beam under multiple types of excitation is numerically studied to demonstrate the feasibility and superiority of the proposed method, and the experimental work is then carried out to testify the effectiveness of the proposed method.

  19. Optimal placement of multiple types of communicating sensors with availability and coverage redundancy constraints

    NASA Astrophysics Data System (ADS)

    Vecherin, Sergey N.; Wilson, D. Keith; Pettit, Chris L.

    2010-04-01

    Determination of an optimal configuration (numbers, types, and locations) of a sensor network is an important practical problem. In most applications, complex signal propagation effects and inhomogeneous coverage preferences lead to an optimal solution that is highly irregular and nonintuitive. The general optimization problem can be strictly formulated as a binary linear programming problem. Due to the combinatorial nature of this problem, however, its strict solution requires significant computational resources (NP-complete class of complexity) and is unobtainable for large spatial grids of candidate sensor locations. For this reason, a greedy algorithm for approximate solution was recently introduced [S. N. Vecherin, D. K. Wilson, and C. L. Pettit, "Optimal sensor placement with terrain-based constraints and signal propagation effects," Unattended Ground, Sea, and Air Sensor Technologies and Applications XI, SPIE Proc. Vol. 7333, paper 73330S (2009)]. Here further extensions to the developed algorithm are presented to include such practical needs and constraints as sensor availability, coverage by multiple sensors, and wireless communication of the sensor information. Both communication and detection are considered in a probabilistic framework. Communication signal and signature propagation effects are taken into account when calculating probabilities of communication and detection. Comparison of approximate and strict solutions on reduced-size problems suggests that the approximate algorithm yields quick and good solutions, which thus justifies using that algorithm for full-size problems. Examples of three-dimensional outdoor sensor placement are provided using a terrain-based software analysis tool.

  20. Autonomous Rover Traverse and Precise Arm Placement on Remotely Designated Targets

    NASA Technical Reports Server (NTRS)

    Felder, Michael; Nesnas, Issa A.; Pivtoraiko, Mihail; Kelly, Alonzo; Volpe, Richard

    2011-01-01

    Exploring planetary surfaces typically involves traversing challenging and unknown terrain and acquiring in-situ measurements at designated locations using arm-mounted instruments. We present field results for a new implementation of an autonomous capability that enables a rover to traverse and precisely place an arm-mounted instrument on remote targets. Using point-and-click mouse commands, a scientist designates targets in the initial imagery acquired from the rover's mast cameras. The rover then autonomously traverse the rocky terrain for a distance of 10 - 15 m, tracks the target(s) of interest during the traverse, positions itself for approaching the target, and then precisely places an arm-mounted instrument within 2-3 cm from the originally designated target. The rover proceeds to acquire science measurements with the instrument. This work advances what has been previously developed and integrated on the Mars Exploration Rovers by using algorithms that are capable of traversing more rock-dense terrains, enabling tight thread-the-needle maneuvers. We integrated these algorithms on the newly refurbished Athena Mars research rover and fielded them in the JPL Mars Yard. We conducted 43 runs with targets at distances ranging from 5 m to 15 m and achieved a success rate of 93% for placement of the instrument within 2-3 cm.

  1. SSD-Optimized Workload Placement with Adaptive Learning and Classification in HPC Environments

    SciTech Connect

    Wan, Lipeng; Lu, Zheng; Cao, Qing; Wang, Feiyi; Oral, H Sarp; Settlemyer, Bradley W

    2014-01-01

    In recent years, non-volatile memory devices such as SSD drives have emerged as a viable storage solution due to their increasing capacity and decreasing cost. Due to the unique capability and capacity requirements in large scale HPC (High Performance Computing) storage environment, a hybrid config- uration (SSD and HDD) may represent one of the most available and balanced solutions considering the cost and performance. Under this setting, effective data placement as well as movement with controlled overhead become a pressing challenge. In this paper, we propose an integrated object placement and movement framework and adaptive learning algorithms to address these issues. Specifically, we present a method that shuffle data objects across storage tiers to optimize the data access performance. The method also integrates an adaptive learning algorithm where real- time classification is employed to predict the popularity of data object accesses, so that they can be placed on, or migrate between SSD or HDD drives in the most efficient manner. We discuss preliminary results based on this approach using a simulator we developed to show that the proposed methods can dynamically adapt storage placements and access pattern as workloads evolve to achieve the best system level performance such as throughput.

  2. Optimal sensor placement for active guided wave interrogation of complex metallic components

    NASA Astrophysics Data System (ADS)

    Coelho, Clyde K.; Kim, Seung Bum; Chattopadhyay, Aditi

    2011-04-01

    With research in structural health monitoring (SHM) moving towards increasingly complex structures for damage interrogation, the placement of sensors is becoming a key issue in the performance of the damage detection methodologies. For ultrasonic wave based approaches, this is especially important because of the sensitivity of the travelling Lamb waves to material properties, geometry and boundary conditions that may obscure the presence of damage if they are not taken into account during sensor placement. The framework proposed in this paper defines a sensing region for a pair of piezoelectric transducers in a pitch-catch damage detection approach by taking into account the material attenuation and probability of false alarm. Using information about the region interrogated by a sensoractuator pair, a simulated annealing optimization framework was implemented in order to place sensors on complex metallic geometries such that a selected minimum damage type and size could be detected with an acceptable probability of false alarm anywhere on the structure. This approach was demonstrated on a lug joint to detect a crack and on a large Naval SHM test bed and resulted in a placement of sensors that was able to interrogate all parts of the structure using the minimum number of transducers.

  3. Autonomous Rover Traverse and Precise Arm Placement on Remotely Designated Targets

    NASA Technical Reports Server (NTRS)

    Nesnas, Issa A.; Pivtoraiko, Mihail N.; Kelly, Alonzo; Fleder, Michael

    2012-01-01

    This software controls a rover platform to traverse rocky terrain autonomously, plan paths, and avoid obstacles using its stereo hazard and navigation cameras. It does so while continuously tracking a target of interest selected from 10 20 m away. The rover drives and tracks the target until it reaches the vicinity of the target. The rover then positions itself to approach the target, deploys its robotic arm, and places the end effector instrument on the designated target to within 2-3-cm accuracy of the originally selected target. This software features continuous navigation in a fairly rocky field in an outdoor environment and the ability to enable the rover to avoid large rocks and traverse over smaller ones. Using point-and-click mouse commands, a scientist designates targets in the initial imagery acquired from the rover s mast cameras. The navigation software uses stereo imaging, traversability analysis, path planning, trajectory generation, and trajectory execution. It also includes visual target tracking of a designated target selected from 10 m away while continuously navigating the rocky terrain. Improvements in this design include steering while driving, which uses continuous curvature paths. There are also several improvements to the traversability analyzer, including improved data fusion of traversability maps that result from pose estimation uncertainties, dealing with boundary effects to enable tighter maneuvers, and handling a wider range of obstacles. This work advances what has been previously developed and integrated on the Mars Exploration Rovers by using algorithms that are capable of traversing more rock-dense terrains, enabling tight, thread-the-needle maneuvers. These algorithms were integrated on the newly refurbished Athena Mars research rover, and were fielded in the JPL Mars Yard. Forty-three runs were conducted with targets at distances ranging from 5 to 15 m, and a success rate of 93% was achieved for placement of the instrument within

  4. Optimal sensor placement for maximum area coverage (MAC) for damage localization in composite structures

    NASA Astrophysics Data System (ADS)

    Thiene, M.; Sharif Khodaei, Z.; Aliabadi, M. H.

    2016-09-01

    In this paper an optimal sensor placement algorithm for attaining the maximum area coverage (MAC) within a sensor network is presented. The proposed novel approach takes into account physical properties of Lamb wave propagation (attenuation profile, direction dependant group velocity due to material anisotropy) and geometrical complexities (boundary reflections, presence of openings) of the structure. A feature of the proposed optimization approach lies in the fact that it is independent of characteristics of the damage detection algorithm (e.g. probability of detection) making it readily up-scalable to large complex composite structures such as aircraft stiffened composite panel. The proposed fitness function (MAC) is independent of damage parameters (type, severity, location). Statistical analysis carried out shows that the proposed optimum sensor network with MAC results in high probability of damage localization. Genetic algorithm is coupled with the fitness function to provide an efficient optimization strategy.

  5. New Approach to Optimize the Apfs Placement Based on Instantaneous Reactive Power Theory by Genetic Algorithm

    NASA Astrophysics Data System (ADS)

    Hashemi-Dezaki, Hamed; Mohammadalizadeh-Shabestary, Masoud; Askarian-Abyaneh, Hossein; Rezaei-Jegarluei, Mohammad

    2014-01-01

    In electrical distribution systems, a great amount of power are wasting across the lines, also nowadays power factors, voltage profiles and total harmonic distortions (THDs) of most loads are not as would be desired. So these important parameters of a system play highly important role in wasting money and energy, and besides both consumers and sources are suffering from a high rate of distortions and even instabilities. Active power filters (APFs) are innovative ideas for solving of this adversity which have recently used instantaneous reactive power theory. In this paper, a novel method is proposed to optimize the allocation of APFs. The introduced method is based on the instantaneous reactive power theory in vectorial representation. By use of this representation, it is possible to asses different compensation strategies. Also, APFs proper placement in the system plays a crucial role in either reducing the losses costs and power quality improvement. To optimize the APFs placement, a new objective function has been defined on the basis of five terms: total losses, power factor, voltage profile, THD and cost. Genetic algorithm has been used to solve the optimization problem. The results of applying this method to a distribution network illustrate the method advantages.

  6. Optimal placement of active braces by using PSO algorithm in near- and far-field earthquakes

    NASA Astrophysics Data System (ADS)

    Mastali, M.; Kheyroddin, A.; Samali, B.; Vahdani, R.

    2016-03-01

    One of the most important issues in tall buildings is lateral resistance of the load-bearing systems against applied loads such as earthquake, wind and blast. Dual systems comprising core wall systems (single or multi-cell core) and moment-resisting frames are used as resistance systems in tall buildings. In addition to adequate stiffness provided by the dual system, most tall buildings may have to rely on various control systems to reduce the level of unwanted motions stemming from severe dynamic loads. One of the main challenges to effectively control the motion of a structure is limitation in distributing the required control along the structure height optimally. In this paper, concrete shear walls are used as secondary resistance system at three different heights as well as actuators installed in the braces. The optimal actuator positions are found by using optimized PSO algorithm as well as arbitrarily. The control performance of buildings that are equipped and controlled using the PSO algorithm method placement is assessed and compared with arbitrary placement of controllers using both near- and far-field ground motions of Kobe and Chi-Chi earthquakes.

  7. A triaxial accelerometer monkey algorithm for optimal sensor placement in structural health monitoring

    NASA Astrophysics Data System (ADS)

    Jia, Jingqing; Feng, Shuo; Liu, Wei

    2015-06-01

    Optimal sensor placement (OSP) technique is a vital part of the field of structural health monitoring (SHM). Triaxial accelerometers have been widely used in the SHM of large-scale structures in recent years. Triaxial accelerometers must be placed in such a way that all of the important dynamic information is obtained. At the same time, the sensor configuration must be optimal, so that the test resources are conserved. The recommended practice is to select proper degrees of freedom (DOF) based upon several criteria and the triaxial accelerometers are placed at the nodes corresponding to these DOFs. This results in non-optimal placement of many accelerometers. A ‘triaxial accelerometer monkey algorithm’ (TAMA) is presented in this paper to solve OSP problems of triaxial accelerometers. The EFI3 measurement theory is modified and involved in the objective function to make it more adaptable in the OSP technique of triaxial accelerometers. A method of calculating the threshold value based on probability theory is proposed to improve the healthy rate of monkeys in a troop generation process. Meanwhile, the processes of harmony ladder climb and scanning watch jump are proposed and given in detail. Finally, Xinghai NO.1 Bridge in Dalian is implemented to demonstrate the effectiveness of TAMA. The final results obtained by TAMA are compared with those of the original monkey algorithm and EFI3 measurement, which show that TAMA can improve computational efficiency and get a better sensor configuration.

  8. Optimal placement of piezoelectric plates for active vibration control of gas turbine blades: experimental results

    NASA Astrophysics Data System (ADS)

    Botta, F.; Marx, N.; Gentili, S.; Schwingshackl, C. W.; Di Mare, L.; Cerri, G.; Dini, D.

    2012-04-01

    It is well known that the gas turbine blade vibrations can give rise to catastrophic failures and a reduction of the blades life because of fatigue related phenomena[1]-[3] . In last two decades, the adoption of piezoelectric elements, has received considerable attention by many researcher for its potential applicability to different areas of mechanical, aerospace, aeronautical and civil engineering. Recently, a number of studies of blades vibration control via piezoelectric plates and patches have been reported[4]-[6] . It was reported that the use of piezoelectric elements can be very effective in actively controlling vibrations. In one of their previous contributions[7] , the authors of the present manuscript studied a model to control the blade vibrations by piezoelectric elements and validated their results using a multi-physics finite elements package (COMSOL) and results from the literature. An optimal placement method of piezoelectric plate has been developed and applied to different loading scenarios for realistic configurations encountered in gas turbine blades. It has been demonstrated that the optimal placement depends on the spectrum of the load, so that segmented piezoelectric patches have been considered and, for different loads, an optimal combination of sequential and/or parallel actuation and control of the segments has been studied. In this paper, an experimental investigation carried out by the authors using a simplified beam configuration is reported and discussed. The test results obtained by the investigators are then compared with the numerical predictions [7] .

  9. Optimal placement of off-stream water sources for ephemeral stream recovery

    USGS Publications Warehouse

    Rigge, Matthew B.; Smart, Alexander; Wylie, Bruce

    2013-01-01

    Uneven and/or inefficient livestock distribution is often a product of an inadequate number and distribution of watering points. Placement of off-stream water practices (OSWP) in pastures is a key consideration in rangeland management plans and is critical to achieving riparian recovery by improving grazing evenness, while improving livestock performance. Effective OSWP placement also minimizes the impacts of livestock use radiating from OSWP, known as the “piosphere.” The objective of this study was to provide land managers with recommendations for the optimum placement of OSWP. Specifically, we aimed to provide minimum offset distances of OSWP to streams and assess the effective range of OSWP using Normalized Difference Vegetation Index (NDVI) values, an indicator of live standing crop. NDVI values were determined from a time-series of Satellite Pour l'Observation de la Terre (SPOT) 20-m images of western South Dakota mixed-grass prairie. The NDVI values in ephemeral stream channels (in-channel) and uplands were extracted from pre- and post-OSWP images taken in 1989 and 2010, respectively. NDVI values were normalized to a reference imagine and subsequently by ecological site to produce nNDVI. Our results demonstrate a significant (P 2 = 0.49, P = 0.05) and increased with average distance to OSWP in a pasture (R2 = 0.43, P = 0.07). Piospheric reduction in nNDVI was observed within 200 m of OSWP, occasionally overlapping in-channel areas. The findings of this study suggest placement of OSWP 200 to 1 250 m from streams to achieve optimal results. These results can be used to increase grazing efficiency by effectively placing OSWP and insure that piospheres do not overlap ecologically important in-channel areas.

  10. On the Design of Smart Parking Networks in the Smart Cities: An Optimal Sensor Placement Model

    PubMed Central

    Bagula, Antoine; Castelli, Lorenzo; Zennaro, Marco

    2015-01-01

    Smart parking is a typical IoT application that can benefit from advances in sensor, actuator and RFID technologies to provide many services to its users and parking owners of a smart city. This paper considers a smart parking infrastructure where sensors are laid down on the parking spots to detect car presence and RFID readers are embedded into parking gates to identify cars and help in the billing of the smart parking. Both types of devices are endowed with wired and wireless communication capabilities for reporting to a gateway where the situation recognition is performed. The sensor devices are tasked to play one of the three roles: (1) slave sensor nodes located on the parking spot to detect car presence/absence; (2) master nodes located at one of the edges of a parking lot to detect presence and collect the sensor readings from the slave nodes; and (3) repeater sensor nodes, also called “anchor” nodes, located strategically at specific locations in the parking lot to increase the coverage and connectivity of the wireless sensor network. While slave and master nodes are placed based on geographic constraints, the optimal placement of the relay/anchor sensor nodes in smart parking is an important parameter upon which the cost and efficiency of the parking system depends. We formulate the optimal placement of sensors in smart parking as an integer linear programming multi-objective problem optimizing the sensor network engineering efficiency in terms of coverage and lifetime maximization, as well as its economic gain in terms of the number of sensors deployed for a specific coverage and lifetime. We propose an exact solution to the node placement problem using single-step and two-step solutions implemented in the Mosel language based on the Xpress-MPsuite of libraries. Experimental results reveal the relative efficiency of the single-step compared to the two-step model on different performance parameters. These results are consolidated by simulation results

  11. On the Design of Smart Parking Networks in the Smart Cities: An Optimal Sensor Placement Model.

    PubMed

    Bagula, Antoine; Castelli, Lorenzo; Zennaro, Marco

    2015-01-01

    Smart parking is a typical IoT application that can benefit from advances in sensor, actuator and RFID technologies to provide many services to its users and parking owners of a smart city. This paper considers a smart parking infrastructure where sensors are laid down on the parking spots to detect car presence and RFID readers are embedded into parking gates to identify cars and help in the billing of the smart parking. Both types of devices are endowed with wired and wireless communication capabilities for reporting to a gateway where the situation recognition is performed. The sensor devices are tasked to play one of the three roles: (1) slave sensor nodes located on the parking spot to detect car presence/absence; (2) master nodes located at one of the edges of a parking lot to detect presence and collect the sensor readings from the slave nodes; and (3) repeater sensor nodes, also called "anchor" nodes, located strategically at specific locations in the parking lot to increase the coverage and connectivity of the wireless sensor network. While slave and master nodes are placed based on geographic constraints, the optimal placement of the relay/anchor sensor nodes in smart parking is an important parameter upon which the cost and efficiency of the parking system depends. We formulate the optimal placement of sensors in smart parking as an integer linear programming multi-objective problem optimizing the sensor network engineering efficiency in terms of coverage and lifetime maximization, as well as its economic gain in terms of the number of sensors deployed for a specific coverage and lifetime. We propose an exact solution to the node placement problem using single-step and two-step solutions implemented in the Mosel language based on the Xpress-MPsuite of libraries. Experimental results reveal the relative efficiency of the single-step compared to the two-step model on different performance parameters. These results are consolidated by simulation results

  12. Optimal Sequential Diagnostic Strategy Generation Considering Test Placement Cost for Multimode Systems.

    PubMed

    Zhang, Shigang; Song, Lijun; Zhang, Wei; Hu, Zheng; Yang, Yongmin

    2015-01-01

    Sequential fault diagnosis is an approach that realizes fault isolation by executing the optimal test step by step. The strategy used, i.e., the sequential diagnostic strategy, has great influence on diagnostic accuracy and cost. Optimal sequential diagnostic strategy generation is an important step in the process of diagnosis system construction, which has been studied extensively in the literature. However, previous algorithms either are designed for single mode systems or do not consider test placement cost. They are not suitable to solve the sequential diagnostic strategy generation problem considering test placement cost for multimode systems. Therefore, this problem is studied in this paper. A formulation is presented. Two algorithms are proposed, one of which is realized by system transformation and the other is newly designed. Extensive simulations are carried out to test the effectiveness of the algorithms. A real-world system is also presented. All the results show that both of them have the ability to solve the diagnostic strategy generation problem, and they have different characteristics. PMID:26457709

  13. Mirror placement optimization for the multi-segmented James Webb Space Telescope primary mirror

    NASA Astrophysics Data System (ADS)

    Porpora, D.; Wachs, J.; Barto, A.; Knight, J. S.

    2014-08-01

    The Primary Mirror (PM) of NASA's James Webb Space Telescope (JWST) consists of 18 segment assemblies that are aligned on-orbit using hexapod actuators to function as a single monolithic optic. The individual segment assemblies are polished into one of three different prescriptions. Each segment of a given prescription may be placed in one of six different locations for that prescription, resulting in tens of millions of possible placement combinations of the 18 segments on the backplane of the telescope. A method is proposed to optimize the placement based on minimizing the known alignment offsets of as-built mirrors in combination with the predicted shifts of each attachment point on the telescope backplane due to material creep, cool down shifts, launch shifts, and gravity release. The optimization routine can be configured to allow for minimization of errors in any of the six rigid-body degrees of freedom and can further reduce selection options based on defined hardware constraints. Such a routine can be utilized to minimize initial misalignments of the PM on-orbit, reducing the need to exercise mirror actuators to achieve an aligned state. The end result is reduced commissioning time and increased probability of success of the mission.

  14. Optimal Sequential Diagnostic Strategy Generation Considering Test Placement Cost for Multimode Systems

    PubMed Central

    Zhang, Shigang; Song, Lijun; Zhang, Wei; Hu, Zheng; Yang, Yongmin

    2015-01-01

    Sequential fault diagnosis is an approach that realizes fault isolation by executing the optimal test step by step. The strategy used, i.e., the sequential diagnostic strategy, has great influence on diagnostic accuracy and cost. Optimal sequential diagnostic strategy generation is an important step in the process of diagnosis system construction, which has been studied extensively in the literature. However, previous algorithms either are designed for single mode systems or do not consider test placement cost. They are not suitable to solve the sequential diagnostic strategy generation problem considering test placement cost for multimode systems. Therefore, this problem is studied in this paper. A formulation is presented. Two algorithms are proposed, one of which is realized by system transformation and the other is newly designed. Extensive simulations are carried out to test the effectiveness of the algorithms. A real-world system is also presented. All the results show that both of them have the ability to solve the diagnostic strategy generation problem, and they have different characteristics. PMID:26457709

  15. Optimal placement and active vibration control for piezoelectric smart flexible cantilever plate

    NASA Astrophysics Data System (ADS)

    Qiu, Zhi-cheng; Zhang, Xian-min; Wu, Hong-xin; Zhang, Hong-hua

    2007-04-01

    Some flexible appendages of spacecraft are cantilever plate structures, such as sun plate and satellite antenna. Thus, vibration problem will be caused by parameter uncertainties and environmental disturbances. In this paper, piezoelectric ceramics patches are used as sensors and actuators to suppress the vibration of the smart flexible clamped plate. Firstly, modal equations and piezoelectric control equations of cantilever plate are derived. Secondly, an optimal placement method for the locations of piezoelectric actuators and sensors is developed based on the degree of observability and controllability indices for cantilever plate. The bending and torsional modes are decoupled by the proposed method using bandwidth Butterworth filter. Thirdly, an efficient control method by combining positive position feedback and proportional-derivative control is proposed for vibration reduction. The analytical results for modal frequencies, transient responses and control responses are carried out. Finally, an experimental setup of piezoelectric smart plate is designed and built up. The modal frequencies and damping ratios of the plate setup are obtained by identification method. Also, the experimental studies on vibration control of the cantilever plate including bending modes and torsional modes are conducted. The analytical and experimental results demonstrate that the presented control method is feasible, and the optimal placement method is effective.

  16. Optimal Capacitor Placement in Radial Distribution Feeders Using Fuzzy-Differential Evolution for Dynamic Load Condition

    NASA Astrophysics Data System (ADS)

    Kannan, S. M.; Renuga, P.; Kalyani, S.; Muthukumaran, E.

    2015-12-01

    This paper proposes new methods to select the optimal values of fixed and switched shunt capacitors in Radial distribution feeders for varying load conditions so as to maximize the annual savings and minimizes the energy loss by taking the capacitor cost into account. The identification of the weak buses, where the capacitors should be placed is decided by a set of rules given by the fuzzy expert system. Then the sizing of the fixed and switched capacitors is modeled using differential evolution (DE) and particle swarm optimization (PSO). A case study with an existing 15 bus rural distribution feeder is presented to illustrate the applicability of the algorithm. Simulation results show the better saving in cost over previous capacitor placement algorithm.

  17. Optimal placement of semi-active joints in large-space truss structures

    NASA Astrophysics Data System (ADS)

    Wirnitzer, Jan; Kistner, A.; Gaul, Lothar

    2002-06-01

    The low structural damping of large space structures and the stringent positioning requirements in missions demand effective vibration suppression. The semi-active approach at hand is based on friction damping due to interfacial slip in semi-active joints which can be controlled by varying the normal pressure in the contact area using a piezo-disc actuator. This paper focuses on the optimal placement of semi-active joints for vibration suppression. The proposed method uses optimality criteria for actuator and sensor locations based on eigenvalues of the controllability and observability gramians. It is stated as a nonlinear multicriteria optimization problem with discrete variables which is solved by a stochastic search algorithm. As final step in the design procedure, parameters of the local feedback controllers assigned to each adaptive joint are optimized with respect to transient response of the structure. The present method is applied to a 10-bay truss structure. Simulation runs of the controlled structure are used to verify the optimization results.

  18. Optimized Parameters for a Mercury Jet Target

    SciTech Connect

    Ding, X.; Kirk, H.

    2010-12-01

    A study of target parameters for a high-power, liquid mercury jet target system for a neutrino factory or muon collider is presented. Using the MARS code, we simulate particle production initiated by incoming protons with kinetic energies between 2 and 100 GeV. For each proton beam energy, we maximize production by varying the geometric parameters of the target: the mercury jet radius, the incoming proton beam angle, and the crossing angle between the mercury jet and the proton beam. The number of muons surviving through an ionization cooling channel is determined as a function of the proton beam energy. We optimize the mercury jet target parameters: the mercury jet radius, the incoming proton beam angle and the crossing angle between the mercury jet and the proton beam for each proton beam energy. The optimized target radius varies from about 0.4 cm to 0.6 cm as the proton beam energy increases. The optimized beam angle varies from 75 mrad to 120 mrad. The optimized crossing angle is near 20 mrad for energies above 5 GeV. These values differ from earlier choices of 67 mrad for the beam angle and 33 mrad for the crossing angle. These new choices for the beam parameters increase the meson production by about 20% compared to the earlier parameters. Our study demonstrates that the maximum meson production efficiency per unit proton beam power occurs when the proton kinetic energy is in the range of 5-15 GeV. Finally, the dependence on energy of the number of muons at the end of the cooling channel is nearly identical to the dependence on energy of the meson production 50 m from the target. This demonstrates that the target parameters can be optimized without the additional step of running the distribution through a code such as ICOOL that simulates the bunching, phase rotation, and cooling.

  19. Sensitivity analysis and optimization of nodal point placement for vibration reduction

    NASA Technical Reports Server (NTRS)

    Pritchard, J. I.; Adelman, H. M.; Haftka, R. T.

    1987-01-01

    A method is developed for sensitivity analysis and optimization of nodal point locations in connection with vibration reduction. A straightforward derivation of the expression for the derivative of nodal locations is given, and the role of the derivative in assessing design trends is demonstrated. An optimization process is developed which uses added lumped masses on the structure as design variables to move the node to a preselected location - for example, where low response amplitude is required or to a point which makes the mode shape nearly orthogonal to the force distribution, thereby minimizing the generalized force. The optimization formulation leads to values for added masses that adjust a nodal location while minimizing the total amount of added mass required to do so. As an example, the node of the second mode of a cantilever box beam is relocated to coincide with the centroid of a prescribed force distribution, thereby reducing the generalized force substantially without adding excessive mass. A comparison with an optimization formulation that directly minimizes the generalized force indicates that nodal placement gives essentially a minimum generalized force when the node is appropriately placed.

  20. Senstitivty analysis and optimization of nodal point placement for vibration reduction

    NASA Technical Reports Server (NTRS)

    Pritchard, J. I.; Adelman, H. M.; Haftka, R. T.

    1986-01-01

    A method is developed for sensitivity analysis and optimization of nodal point locations in connection with vibration reduction. A straightforward derivation of the expression for the derivative of nodal locations is given, and the role of the derivative in assessing design trends is demonstrated. An optimization process is developed which uses added lumped masses on the structure as design variables to move the node to a preselected location - for example, where low response amplitude is required or to a point which makes the mode shape nearly orthogonal to the force distribution, thereby minimizing the generalized force. The optimization formulation leads to values for added masses that adjust a nodal location while minimizing the total amount of added mass required to do so. As an example, the node of the second mode of a cantilever box beam is relocated to coincide with the centroid of a prescribed force distribution, thereby reducing the generalized force substantially without adding excessive mass. A comparison with an optimization formulation that directly minimizes the generalized force indicates that nodal placement gives essentially a minimum generalized force when the node is appropriately placed.

  1. Field-Based Optimal Placement of Antennas for Body-Worn Wireless Sensors.

    PubMed

    Januszkiewicz, Łukasz; Di Barba, Paolo; Hausman, Sławomir

    2016-01-01

    We investigate a case of automated energy-budget-aware optimization of the physical position of nodes (sensors) in a Wireless Body Area Network (WBAN). This problem has not been presented in the literature yet, as opposed to antenna and routing optimization, which are relatively well-addressed. In our research, which was inspired by a safety-critical application for firefighters, the sensor network consists of three nodes located on the human body. The nodes communicate over a radio link operating in the 2.4 GHz or 5.8 GHz ISM frequency band. Two sensors have a fixed location: one on the head (earlobe pulse oximetry) and one on the arm (with accelerometers, temperature and humidity sensors, and a GPS receiver), while the position of the third sensor can be adjusted within a predefined region on the wearer's chest. The path loss between each node pair strongly depends on the location of the nodes and is difficult to predict without performing a full-wave electromagnetic simulation. Our optimization scheme employs evolutionary computing. The novelty of our approach lies not only in the formulation of the problem but also in linking a fully automated optimization procedure with an electromagnetic simulator and a simplified human body model. This combination turns out to be a computationally effective solution, which, depending on the initial placement, has a potential to improve performance of our example sensor network setup by up to about 20 dB with respect to the path loss between selected nodes. PMID:27196911

  2. Reduction of spillover effects on independent modal space control through optimal placement of sensors and actuators

    NASA Astrophysics Data System (ADS)

    Cinquemani, S.; Ferrari, D.; Bayati, I.

    2015-08-01

    The independent modal space control (IMSC) technique can be profitably used to suppress vibration in flexible structures by increasing the damping of the modes involved, without changing the corresponding natural frequencies and modal shapes. Reducing vibration means reducing the associated noise and enhancing the performance of the system and its fatigue durability. The main limitations of this approach are related to spillover effects due to the dynamics of unmodeled modes. This work investigates analytically how spillover effects in IMSC are closely related to the number and the position of thesensors and actuators involved, in addition to the reduced model adopted to synthesize the control itself. The performance of the IMSC technique is optimized by means of genetic algorithms to reduce spillover effects, finding the best placements for sensors and actuators. Theoretical aspects are supported by numerical simulations.

  3. Multi-projector auto-calibration and placement optimization for non-planar surfaces

    NASA Astrophysics Data System (ADS)

    Li, Dong; Xie, Jinghui; Zhao, Lu; Zhou, Lijing; Weng, Dongdong

    2015-10-01

    Non-planar projection has been widely applied in virtual reality and digital entertainment and exhibitions because of its flexible layout and immersive display effects. Compared with planar projection, a non-planar projection is more difficult to achieve because projector calibration and image distortion correction are difficult processes. This paper uses a cylindrical screen as an example to present a new method for automatically calibrating a multi-projector system in a non-planar environment without using 3D reconstruction. This method corrects the geometric calibration error caused by the screen's manufactured imperfections, such as an undulating surface or a slant in the vertical plane. In addition, based on actual projection demand, this paper presents the overall performance evaluation criteria for the multi-projector system. According to these criteria, we determined the optimal placement for the projectors. This method also extends to surfaces that can be parameterized, such as spheres, ellipsoids, and paraboloids, and demonstrates a broad applicability.

  4. Mining metabolic networks for optimal drug targets.

    PubMed

    Sridhar, Padmavati; Song, Bin; Kahveci, Tamer; Ranka, Sanjay

    2008-01-01

    Recent advances in bioinformatics promote drug-design methods that aim to reduce side-effects. Efficient computational methods are required to identify the optimal enzyme-combination (i.e., drug targets) whose inhibition, will achieve the required effect of eliminating a given target set of compounds, while incurring minimal side-effects. We formulate the optimal enzyme-combination identification problem as an optimization problem on metabolic networks. We define a graph based computational damage model that encapsulates the impact of enzymes onto compounds in metabolic networks. We develop a branch-and-bound algorithm, named OPMET, to explore the search space dynamically. We also develop two filtering strategies to prune the search space while still guaranteeing an optimal solution. They compute an upper bound to the number of target compounds eliminated and a lower bound to the side-effect respectively. Our experiments on the human metabolic network demonstrate that the proposed algorithm can accurately identify the target enzymes for known successful drugs in the literature. Our experiments also show that OPMET can reduce the total search time by several orders of magnitude as compared to the exhaustive search. PMID:18229694

  5. Improved targeting device and computer navigation for accurate placement of brachytherapy needles

    SciTech Connect

    Pappas, Ion P.I.; Ryan, Paul; Cossmann, Peter; Kowal, Jens; Borgeson, Blake; Caversaccio, Marco

    2005-06-15

    Successful treatment of skull base tumors with interstitial brachytherapy requires high targeting accuracy for the brachytherapy needles to avoid harming vital anatomical structures. To enable safe placement of the needles in this area, we developed an image-based planning and navigation system for brachytherapy, which includes a custom-made mechanical positioning arm that allows rough and fine adjustment of the needle position. The fine-adjustment mechanism consists of an XYZ microstage at the base of the arm and a needle holder with two fine-adjustable inclinations. The rotation axes of the inclinations cross at the tip of the needle so that the inclinational adjustments do not interfere with the translational adjustments. A vacuum cushion and a noninvasive fixation frame are used for the head immobilization. To avoid mechanical bending of the needles due to the weight of attached tracking markers, which would be detrimental for targeting accuracy, only a single LED marker on the tail of the needle is used. An experimental phantom-based targeting study with this setup demonstrated that a positioning accuracy of 1.4 mm (rms) can be achieved. The study showed that the proposed setup allows brachytherapy needles to be easily aligned and inserted with high targeting accuracy according to a preliminary plan. The achievable accuracy is higher than if the needles are inserted manually. The proposed system can be linked to a standard afterloader and standard dosimetry planning module. The associated additional effort is reasonable for the clinical practice and therefore the proposed procedure provides a promising tool for the safe treatment of tumors in the skull base area.

  6. The effects of initial conditions and control time on optimal actuator placement via a max-min Genetic Algorithm

    SciTech Connect

    Redmond, J.; Parker, G.

    1993-07-01

    This paper examines the role of the control objective and the control time in determining fuel-optimal actuator placement for structural vibration suppression. A general theory is developed that can be easily extended to include alternative performance metrics such as energy and time-optimal control. The performance metric defines a convex admissible control set which leads to a max-min optimization problem expressing optimal location as a function of initial conditions and control time. A solution procedure based on a nested Genetic Algorithm is presented and applied to an example problem. Results indicate that the optimal locations vary widely as a function of control time and initial conditions.

  7. Optimal Placement of Distributed Generation Units in a Distribution System with Uncertain Topologies using Monte Carlo Simulation

    NASA Astrophysics Data System (ADS)

    Donadel, Clainer Bravin; Fardin, Jussara Farias; Encarnação, Lucas Frizera

    2015-10-01

    In the literature, several papers propose new methodologies to determine the optimal placement/sizing of medium size Distributed Generation Units (DGs), using heuristic algorithms like Genetic Algorithm (GA) and Particle Swarm Optimization (PSO). However, in all methodologies, the optimal placement solution is strongly dependent of network topologies. Therefore, a specific solution is valid only for a particular network topology. Furthermore, such methodologies does not consider the presence of small DGs, whose connection point cannot be defined by Distribution Network Operators (DNOs). In this paper it is proposed a new methodology to determine the optimal location of medium size DGs in a distribution system with uncertain topologies, considering the particular behavior of small DGs, using Monte Carlo Simulation.

  8. Branch target buffer design and optimization

    NASA Technical Reports Server (NTRS)

    Perleberg, Chris H.; Smith, Alan J.

    1993-01-01

    Consideration is given to two major issues in the design of branch target buffers (BTBs), with the goal of achieving maximum performance for a given number of bits allocated to the BTB design. The first issue is BTB management; the second is what information to keep in the BTB. A number of solutions to these problems are reviewed, and various optimizations in the design of BTBs are discussed. Design target miss ratios for BTBs are developed, making it possible to estimate the performance of BTBs for real workloads.

  9. Impact of Brine Extraction and Well Placement Optimization on Geologic Carbon Storage Capacity Estimation

    NASA Astrophysics Data System (ADS)

    Ganjdanesh, R.; Hosseini, S. A.

    2015-12-01

    Capacity of carbon dioxide storage aquifers depends on a variety of factors including geologic properties and operational designs. The injection well numbers, well spacing and location, open versus closed boundary conditions, and injection with or without extraction of brine are of the parameters that impact the capacity of a storage site. Brine extraction from storage formations has been introduced as an effective strategy for enhancing the storage capacity and mitigating the risk of rapid pressure buildup. It is proposed that extracted brine can be disposed within an overlying formation or will be desalinated at surface facilities. Optimal well placement and rate of CO2 injection/brine extraction control achieving a predefined pressure constraint at the end of a specific period of storage operation. Reservoir simulation study is required to solve the two-phase flow of gas/brine and pressure buildup in the aquifer. Numerical simulation of geological storage using multiple injectors and extractors is costly and time consuming. Instead, analytical simulation can provide the results with a very good accuracy in a fraction of time compared to the numerical simulation. In this study, an analytical solution was implemented for pressure buildup calculation. The analytical model includes the effects of two-phase relative permeability, CO2 dissolution into reservoir brine and formation of a dry-out zone around the wellbore. Through the optimization algorithm coupled with analytical model, the optimal rates and locations of CO2 injectors and brine extractors were estimated, while simultaneously satisfying the pressure constraint to avoid fracture pressure in all injectors. The optimized results of analytical model was verified with a numerical simulator for several reservoir conditions, well configurations and operating constraints. The comparison of the results shows that the analytical model is a reliable tool for preliminary capacity estimation of saline aquifers and

  10. Simultaneous optimization of force and placement of friction dampers under seismic loading

    NASA Astrophysics Data System (ADS)

    Fleck Fadel Miguel, Letícia; Fleck Fadel Miguel, Leandro; Holdorf Lopez, Rafael

    2016-04-01

    It is known that the use of passive energy-dissipation devices, such as friction dampers, reduces considerably the dynamic response of a structure subjected to earthquake ground motions. Nevertheless, the parameters of each damper and the best placement of these devices remain difficult to determine. Some articles on optimum design of tuned mass dampers and viscous dampers have been published; however, there is a lack of studies on optimization of friction dampers. The main contribution of this article is to propose a methodology to simultaneously optimize the location of friction dampers and their friction forces in structures subjected to seismic loading, to achieve a desired level of reduction in the response. For this purpose, the recently developed backtracking search optimization algorithm (BSA) is employed, which can deal with optimization problems involving mixed discrete and continuous variables. For illustration purposes, two different structures are presented. The first is a six-storey shear building and the second is a transmission line tower. In both cases, the forces and positions of friction dampers are the design variables, while the objective functions are to minimize the interstorey drift for the first case and to minimize the maximum displacement at the top of the tower for the second example. The results show that the proposed method was able to reduce the interstorey drift of the shear building by more than 65% and the maximum displacement at the top of the tower by approximately 55%, with only three friction dampers. The proposed methodology is quite general and it could be recommended as an effective tool for optimum design of friction dampers for structural response control. Thus, this article shows that friction dampers can be designed in a safe and economic way.

  11. Field-Based Optimal Placement of Antennas for Body-Worn Wireless Sensors

    PubMed Central

    Januszkiewicz, Łukasz; Di Barba, Paolo; Hausman, Sławomir

    2016-01-01

    We investigate a case of automated energy-budget-aware optimization of the physical position of nodes (sensors) in a Wireless Body Area Network (WBAN). This problem has not been presented in the literature yet, as opposed to antenna and routing optimization, which are relatively well-addressed. In our research, which was inspired by a safety-critical application for firefighters, the sensor network consists of three nodes located on the human body. The nodes communicate over a radio link operating in the 2.4 GHz or 5.8 GHz ISM frequency band. Two sensors have a fixed location: one on the head (earlobe pulse oximetry) and one on the arm (with accelerometers, temperature and humidity sensors, and a GPS receiver), while the position of the third sensor can be adjusted within a predefined region on the wearer’s chest. The path loss between each node pair strongly depends on the location of the nodes and is difficult to predict without performing a full-wave electromagnetic simulation. Our optimization scheme employs evolutionary computing. The novelty of our approach lies not only in the formulation of the problem but also in linking a fully automated optimization procedure with an electromagnetic simulator and a simplified human body model. This combination turns out to be a computationally effective solution, which, depending on the initial placement, has a potential to improve performance of our example sensor network setup by up to about 20 dB with respect to the path loss between selected nodes. PMID:27196911

  12. Optimal sensor placement for time-domain identification using a wavelet-based genetic algorithm

    NASA Astrophysics Data System (ADS)

    Mahdavi, Seyed Hossein; Razak, Hashim Abdul

    2016-06-01

    This paper presents a wavelet-based genetic algorithm strategy for optimal sensor placement (OSP) effective for time-domain structural identification. Initially, the GA-based fitness evaluation is significantly improved by using adaptive wavelet functions. Later, a multi-species decimal GA coding system is modified to be suitable for an efficient search around the local optima. In this regard, a local operation of mutation is introduced in addition with regeneration and reintroduction operators. It is concluded that different characteristics of applied force influence the features of structural responses, and therefore the accuracy of time-domain structural identification is directly affected. Thus, the reliable OSP strategy prior to the time-domain identification will be achieved by those methods dealing with minimizing the distance of simulated responses for the entire system and condensed system considering the force effects. The numerical and experimental verification on the effectiveness of the proposed strategy demonstrates the considerably high computational performance of the proposed OSP strategy, in terms of computational cost and the accuracy of identification. It is deduced that the robustness of the proposed OSP algorithm lies in the precise and fast fitness evaluation at larger sampling rates which result in the optimum evaluation of the GA-based exploration and exploitation phases towards the global optimum solution.

  13. A novel method for optimal capacitor placement and sizing in distribution systems with nonlinear loads and DG using GA

    NASA Astrophysics Data System (ADS)

    Taher, Seyed Abbas; Hasani, Mohammad; Karimian, Ali

    2011-02-01

    A genetic algorithm (GA) is proposed for simultaneous power quality improvement, optimal placement and sizing of fixed capacitor banks in radial distribution networks with nonlinear loads and distributed generation (DG) imposing voltage-current harmonics. In distribution systems, nonlinear loads and DGs are often considered as harmonic sources. For optimizing capacitor placement and sizing in the distribution system, objective function includes the cost of power losses, energy losses and capacitor banks. At the same time, constraints include voltage limits, number/size of installed capacitors (at each bus) and the power quality limits of standard IEEE-519. In this study, new fitness function is used to solve the constrained optimization problem with discrete variables. Simulation results for two IEEE distorted networks (18-bus and 33-bus test systems) are presented and solutions of the proposed method are compared with those of previous methods described in the literature. The main contribution of this paper is computing the (near) global solution with a lower probability of getting stuck at a local optimum and weak dependency on initial conditions, while avoiding numerical problems in large systems. Results show that proposed method could be effectively used for optimal capacitor placement and sizing in distorted distribution systems.

  14. MaNGA: Target selection and Optimization

    NASA Astrophysics Data System (ADS)

    Wake, David

    2016-01-01

    The 6-year SDSS-IV MaNGA survey will measure spatially resolved spectroscopy for 10,000 nearby galaxies using the Sloan 2.5m telescope and the BOSS spectrographs with a new fiber arrangement consisting of 17 individually deployable IFUs. We present the simultaneous design of the target selection and IFU size distribution to optimally meet our targeting requirements. The requirements for the main samples were to use simple cuts in redshift and magnitude to produce an approximately flat number density of targets as a function of stellar mass, ranging from 1x109 to 1x1011 M⊙, and radial coverage to either 1.5 (Primary sample) or 2.5 (Secondary sample) effective radii, while maximizing S/N and spatial resolution. In addition we constructed a "Color-Enhanced" sample where we required 25% of the targets to have an approximately flat number density in the color and mass plane. We show how these requirements are met using simple absolute magnitude (and color) dependent redshift cuts applied to an extended version of the NASA Sloan Atlas (NSA), how this determines the distribution of IFU sizes and the resulting properties of the MaNGA sample.

  15. MaNGA: Target selection and Optimization

    NASA Astrophysics Data System (ADS)

    Wake, David

    2015-01-01

    The 6-year SDSS-IV MaNGA survey will measure spatially resolved spectroscopy for 10,000 nearby galaxies using the Sloan 2.5m telescope and the BOSS spectrographs with a new fiber arrangement consisting of 17 individually deployable IFUs. We present the simultaneous design of the target selection and IFU size distribution to optimally meet our targeting requirements. The requirements for the main samples were to use simple cuts in redshift and magnitude to produce an approximately flat number density of targets as a function of stellar mass, ranging from 1x109 to 1x1011 M⊙, and radial coverage to either 1.5 (Primary sample) or 2.5 (Secondary sample) effective radii, while maximizing S/N and spatial resolution. In addition we constructed a 'Color-Enhanced' sample where we required 25% of the targets to have an approximately flat number density in the color and mass plane. We show how these requirements are met using simple absolute magnitude (and color) dependent redshift cuts applied to an extended version of the NASA Sloan Atlas (NSA), how this determines the distribution of IFU sizes and the resulting properties of the MaNGA sample.

  16. Method for Vibration Response Simulation and Sensor Placement Optimization of a Machine Tool Spindle System with a Bearing Defect

    PubMed Central

    Cao, Hongrui; Niu, Linkai; He, Zhengjia

    2012-01-01

    Bearing defects are one of the most important mechanical sources for vibration and noise generation in machine tool spindles. In this study, an integrated finite element (FE) model is proposed to predict the vibration responses of a spindle bearing system with localized bearing defects and then the sensor placement for better detection of bearing faults is optimized. A nonlinear bearing model is developed based on Jones' bearing theory, while the drawbar, shaft and housing are modeled as Timoshenko's beam. The bearing model is then integrated into the FE model of drawbar/shaft/housing by assembling equations of motion. The Newmark time integration method is used to solve the vibration responses numerically. The FE model of the spindle-bearing system was verified by conducting dynamic tests. Then, the localized bearing defects were modeled and vibration responses generated by the outer ring defect were simulated as an illustration. The optimization scheme of the sensor placement was carried out on the test spindle. The results proved that, the optimal sensor placement depends on the vibration modes under different boundary conditions and the transfer path between the excitation and the response. PMID:23012514

  17. SUSTAIN -AN EVALUATION AND COST-OPTIMIZATION TOOL FOR PLACEMENT OF BMPS

    EPA Science Inventory

    Since 2003, the U.S. Environmental Protection Agency (USEPA) has been developing a decision support system for placement of best management practices (BMPs) to assist stormwater management professionals in planning for BMPs implementation at strategic locations in urban watershed...

  18. Data on four criteria for targeting the placement of conservation buffers in agricultural landscapes.

    PubMed

    Qiu, Zeyuan; Dosskey, Michael G; Kang, Yang

    2016-06-01

    Four criteria are generally used to prioritize agricultural lands for placing conservation buffers. The criteria include soil erodibility, hydrological sensitivity, wildlife habitat, and impervious surface rate that capture conservation buffers' benefits in reducing soil erosion, controlling runoff generation, enhancing wildlife habitat, and mitigating stormwater impacts, respectively. This article describes the data used to derive the values of those attributes and a scheme to classify the values in multi-criteria analysis of conservation buffer placement in "Choosing between alternative placement strategies for conservation buffers using borda count" [1]. PMID:27222843

  19. Data on four criteria for targeting the placement of conservation buffers in agricultural landscapes

    PubMed Central

    Qiu, Zeyuan; Dosskey, Michael G.; Kang, Yang

    2016-01-01

    Four criteria are generally used to prioritize agricultural lands for placing conservation buffers. The criteria include soil erodibility, hydrological sensitivity, wildlife habitat, and impervious surface rate that capture conservation buffers’ benefits in reducing soil erosion, controlling runoff generation, enhancing wildlife habitat, and mitigating stormwater impacts, respectively. This article describes the data used to derive the values of those attributes and a scheme to classify the values in multi-criteria analysis of conservation buffer placement in “Choosing between alternative placement strategies for conservation buffers using borda count” [1]. PMID:27222843

  20. Dose-shaping using targeted sparse optimization

    SciTech Connect

    Sayre, George A.; Ruan, Dan

    2013-07-15

    }{sup sparse} improves tradeoff between planning goals by 'sacrificing' voxels that have already been violated to improve PTV coverage, PTV homogeneity, and/or OAR-sparing. In doing so, overall plan quality is increased since these large violations only arise if a net reduction in E{sub tot}{sup sparse} occurs as a result. For example, large violations to dose prescription in the PTV in E{sub tot}{sup sparse}-optimized plans will naturally localize to voxels in and around PTV-OAR overlaps where OAR-sparing may be increased without compromising target coverage. The authors compared the results of our method and the corresponding clinical plans using analyses of DVH plots, dose maps, and two quantitative metrics that quantify PTV homogeneity and overdose. These metrics do not penalize underdose since E{sub tot}{sup sparse}-optimized plans were planned such that their target coverage was similar or better than that of the clinical plans. Finally, plan deliverability was assessed with the 2D modulation index.Results: The proposed method was implemented using IBM's CPLEX optimization package (ILOG CPLEX, Sunnyvale, CA) and required 1-4 min to solve with a 12-core Intel i7 processor. In the testing procedure, the authors optimized for several points on the Pareto surface of four 7-field 6MV prostate cases that were optimized for different levels of PTV homogeneity and OAR-sparing. The generated results were compared against each other and the clinical plan by analyzing their DVH plots and dose maps. After developing intuition by planning the four prostate cases, which had relatively few tradeoffs, the authors applied our method to a 7-field 6 MV pancreas case and a 9-field 6MV head-and-neck case to test the potential impact of our method on more challenging cases. The authors found that our formulation: (1) provided excellent flexibility for balancing OAR-sparing with PTV homogeneity; and (2) permitted the dose planner more control over the evolution of the PTV's spatial dose

  1. Bayesian probabilistic structural modeling for optimal sensor placement in ultrasonic guided wave-based structural health monitoring

    NASA Astrophysics Data System (ADS)

    Flynn, Eric B.; Todd, Michael D.

    2010-03-01

    Many optimal sensor placement methods for structural health monitoring establish performance metrics based on the detection of a limited set of damage states and locations. In guided wave-based inspection, however, monitoring is carried out over a continuous region with a continuous distribution of possible damage locations, types, sizes, and orientations. Here, traveling waves are excited and then received by a set of transducers with the intent of detecting and localizing previously unobserved scattering sources that are associated with damage. To measure sensor network performance in this application, we implement a Bayesian experimental design approach by computing the total posterior expected cost of detection over the entire monitoring region. Since the optimization usually must be carried out using a computationally expensive meta-heuristic such as a genetic algorithm, efficient modeling of the interrogation process is key to solving this distributed sensor placement problem. In this work, we implement a previously developed semi-analytical modeling approach for wave scattering within our Bayesian probabilistic framework in order to optimally place active sensors for detecting cracks of unknown location, size, and orientation. This involves assuming a set of a priori probability distributions on the three unknowns and defining spatial distributions of cost associated with type I and type II detection error. These parameters are driven by the geometry, material, in-service structural loading, and performance requirements of the structure. Through a set of sensor placement examples, we demonstrate how changes in the probability and cost distributions will dramatically alter the optimal layout of the transducer network.

  2. Automated Zebrafish Chorion Removal and Single Embryo Placement: Optimizing Throughput of Zebrafish Developmental Toxicity Screens

    PubMed Central

    Mandrell, David; Truong, Lisa; Jephson, Caleb; Sarker, Mushfiqur R.; Moore, Aaron; Lang, Christopher; Simonich, Michael T.; Tanguay, Robert L.

    2012-01-01

    The potential of the developing zebrafish model for toxicology and drug discovery is limited by inefficient approaches to manipulating and chemically exposing zebrafish embryos—namely, manual placement of embryos into 96- or 384-well plates and exposure of embryos while still in the chorion, a barrier of poorly characterized permeability enclosing the developing embryo. We report the automated dechorionation of 1600 embryos at once at 4 h postfertilization (hpf) and placement of the dechorionated embryos into 96-well plates for exposure by 6 hpf. The process removed ≥95% of the embryos from their chorions with 2% embryo mortality by 24 hpf, and 2% of the embryos malformed at 120 hpf. The robotic embryo placement allocated 6-hpf embryos to 94.7% ± 4.2% of the wells in multiple 96-well trials. The rate of embryo mortality was 2.8% (43 of 1536) from robotic handling, the rate of missed wells was 1.2% (18 of 1536), and the frequency of multipicks was <0.1%. Embryo malformations observed at 24 hpf occurred nearly twice as frequently from robotic handling (16 of 864; 1.9%) as from manual pipetting (9 of 864; 1%). There was no statistical difference between the success of performing the embryo placement robotically or manually. PMID:22357610

  3. AN EVALUATION AND COST-OPTIMIZATION TOOL FOR PLACEMENT OF BMPS

    EPA Science Inventory

    To assist stormwater management professionals in planning for best management practices (BMPs) implementation, the U.S. Environmental Protection Agency (USEPA) is developing a decision-support system for placement of BMPs at strategic locations in urban watersheds. This tool wil...

  4. Optimal base station placement for wireless sensor networks with successive interference cancellation.

    PubMed

    Shi, Lei; Zhang, Jianjun; Shi, Yi; Ding, Xu; Wei, Zhenchun

    2015-01-01

    We consider the base station placement problem for wireless sensor networks with successive interference cancellation (SIC) to improve throughput. We build a mathematical model for SIC. Although this model cannot be solved directly, it enables us to identify a necessary condition for SIC on distances from sensor nodes to the base station. Based on this relationship, we propose to divide the feasible region of the base station into small pieces and choose a point within each piece for base station placement. The point with the largest throughput is identified as the solution. The complexity of this algorithm is polynomial. Simulation results show that this algorithm can achieve about 25% improvement compared with the case that the base station is placed at the center of the network coverage area when using SIC. PMID:25594600

  5. Altered Passive Eruption Complicating Optimal Orthodontic Bracket Placement: A Case Report and Review of Literature

    PubMed Central

    Chitra, Prasad

    2015-01-01

    An unusual case of altered passive eruption with gingival hyperpigmentation and a Class I malocclusion in a 12-year-old girl having no previous history of medication is presented. The patient reported with spacing in the upper arch, moderate crowding in the lower arch, anterior crossbite and excessive gingival tissue on the labial surfaces of teeth in both the arches. The inadequate crown lengths made placement of the orthodontic brackets difficult. Preadjusted orthodontic brackets have a very precise placement protocol which can affect tooth movement in all 3 planes of space if violated. The periodontal condition was diagnosed as altered passive eruption Type IA. Interdisciplinary treatment protocols including periodontal surgical and orthodontic procedures were used. The periodontal surgical procedures were carried out prior to orthodontic therapy and the results obtained were satisfactory. It is suggested that orthodontists should be aware of conditions like altered passive eruption and modalities of management. In most instances, orthodontic therapy is not hindered. PMID:26672498

  6. Altered Passive Eruption Complicating Optimal Orthodontic Bracket Placement: A Case Report and Review of Literature.

    PubMed

    Pulgaonkar, Rohan; Chitra, Prasad

    2015-11-01

    An unusual case of altered passive eruption with gingival hyperpigmentation and a Class I malocclusion in a 12-year-old girl having no previous history of medication is presented. The patient reported with spacing in the upper arch, moderate crowding in the lower arch, anterior crossbite and excessive gingival tissue on the labial surfaces of teeth in both the arches. The inadequate crown lengths made placement of the orthodontic brackets difficult. Preadjusted orthodontic brackets have a very precise placement protocol which can affect tooth movement in all 3 planes of space if violated. The periodontal condition was diagnosed as altered passive eruption Type IA. Interdisciplinary treatment protocols including periodontal surgical and orthodontic procedures were used. The periodontal surgical procedures were carried out prior to orthodontic therapy and the results obtained were satisfactory. It is suggested that orthodontists should be aware of conditions like altered passive eruption and modalities of management. In most instances, orthodontic therapy is not hindered. PMID:26672498

  7. Optimal Base Station Placement for Wireless Sensor Networks with Successive Interference Cancellation

    PubMed Central

    Shi, Lei; Zhang, Jianjun; Shi, Yi; Ding, Xu; Wei, Zhenchun

    2015-01-01

    We consider the base station placement problem for wireless sensor networks with successive interference cancellation (SIC) to improve throughput. We build a mathematical model for SIC. Although this model cannot be solved directly, it enables us to identify a necessary condition for SIC on distances from sensor nodes to the base station. Based on this relationship, we propose to divide the feasible region of the base station into small pieces and choose a point within each piece for base station placement. The point with the largest throughput is identified as the solution. The complexity of this algorithm is polynomial. Simulation results show that this algorithm can achieve about 25% improvement compared with the case that the base station is placed at the center of the network coverage area when using SIC. PMID:25594600

  8. An Improved Levenberg-Marquardt Solver for Multiple-Target Optimization Multiple-Target Optimization

    NASA Astrophysics Data System (ADS)

    Shasharina, S. G.; Cary, J. R.

    1999-11-01

    The Levenberg-Marquardt optimization algorithm as usually developed requires that the user provide an algorithm for calculating the derivatives of the residuals (target functions) with respect to the parameters. In the case optimization of complex systems, such as stellarators, these derivatives are usually calculated by numerical differentiation. This causes the computational effort to increase by a factor of (N+1), where N is the number of parameters. In this poster we discuss the coupling of the Broyden update method for calculation of derivatives in multiple dimensions along with the Levenberg-Marquardt minimization algorithm. Tests of implementations of this algorithm in C++ will be presented. For use with Fortran codes, this requires that such codes be converted to libraries and wrapped in C. This process will also be discussed.

  9. Placement of Base Stations in Broadband Power Line Communications Access Networks by Means of Multi-criteria Optimization

    NASA Astrophysics Data System (ADS)

    Haidine, Abdelfatteh; Lehnert, Ralf

    Broadband Power Line Communications (B-PLC) technology is an alternative for broadband access networks, allowing bit rates up to currently 200Mbps. This technique uses the wiring of the low-voltage grid in order to offer to the users the telecommunications services, such as Internet, VoIP, VoD, etc. The B-PLC design process is sub-divided into two parts: the Generalized Base Station Placement (GBSP) problem and the PLC Channel Allocation Problem (P-CAP). This paper focuses on GBSP that is modeled as multi-criteria combinatorial optimization problem. Based on our published mathematical modeling, this paper supplies more numerical experiments for the evaluation of Multi-Objective Evolutionary Algorithms (MOEAs) in solving GBSP. Their performance is compared with the single-objective optimization.

  10. Optimal Geometrical Set for Automated Marker Placement to Virtualized Real-Time Facial Emotions

    PubMed Central

    Maruthapillai, Vasanthan; Murugappan, Murugappan

    2016-01-01

    In recent years, real-time face recognition has been a major topic of interest in developing intelligent human-machine interaction systems. Over the past several decades, researchers have proposed different algorithms for facial expression recognition, but there has been little focus on detection in real-time scenarios. The present work proposes a new algorithmic method of automated marker placement used to classify six facial expressions: happiness, sadness, anger, fear, disgust, and surprise. Emotional facial expressions were captured using a webcam, while the proposed algorithm placed a set of eight virtual markers on each subject’s face. Facial feature extraction methods, including marker distance (distance between each marker to the center of the face) and change in marker distance (change in distance between the original and new marker positions), were used to extract three statistical features (mean, variance, and root mean square) from the real-time video sequence. The initial position of each marker was subjected to the optical flow algorithm for marker tracking with each emotional facial expression. Finally, the extracted statistical features were mapped into corresponding emotional facial expressions using two simple non-linear classifiers, K-nearest neighbor and probabilistic neural network. The results indicate that the proposed automated marker placement algorithm effectively placed eight virtual markers on each subject’s face and gave a maximum mean emotion classification rate of 96.94% using the probabilistic neural network. PMID:26859884

  11. Optimal Geometrical Set for Automated Marker Placement to Virtualized Real-Time Facial Emotions.

    PubMed

    Maruthapillai, Vasanthan; Murugappan, Murugappan

    2016-01-01

    In recent years, real-time face recognition has been a major topic of interest in developing intelligent human-machine interaction systems. Over the past several decades, researchers have proposed different algorithms for facial expression recognition, but there has been little focus on detection in real-time scenarios. The present work proposes a new algorithmic method of automated marker placement used to classify six facial expressions: happiness, sadness, anger, fear, disgust, and surprise. Emotional facial expressions were captured using a webcam, while the proposed algorithm placed a set of eight virtual markers on each subject's face. Facial feature extraction methods, including marker distance (distance between each marker to the center of the face) and change in marker distance (change in distance between the original and new marker positions), were used to extract three statistical features (mean, variance, and root mean square) from the real-time video sequence. The initial position of each marker was subjected to the optical flow algorithm for marker tracking with each emotional facial expression. Finally, the extracted statistical features were mapped into corresponding emotional facial expressions using two simple non-linear classifiers, K-nearest neighbor and probabilistic neural network. The results indicate that the proposed automated marker placement algorithm effectively placed eight virtual markers on each subject's face and gave a maximum mean emotion classification rate of 96.94% using the probabilistic neural network. PMID:26859884

  12. Targeted Gene Therapies: Tools, Applications, Optimization

    PubMed Central

    Humbert, Olivier; Davis, Luther; Maizels, Nancy

    2012-01-01

    Many devastating human diseases are caused by mutations in a single gene that prevent a somatic cell from carrying out its essential functions, or by genetic changes acquired as a result of infectious disease or in the course of cell transformation. Targeted gene therapies have emerged as potential strategies for treatment of such diseases. These therapies depend upon rare-cutting endonucleases to cleave at specific sites in or near disease genes. Targeted gene correction provides a template for homology-directed repair, enabling the cell's own repair pathways to erase the mutation and replace it with the correct sequence. Targeted gene disruption ablates the disease gene, disabling its function. Gene targeting can also promote other kinds of genome engineering, including mutation, insertion, or gene deletion. Targeted gene therapies present significant advantages compared to approaches to gene therapy that depend upon delivery of stably expressing transgenes. Recent progress has been fueled by advances in nuclease discovery and design, and by new strategies that maximize efficiency of targeting and minimize off-target damage. Future progress will build on deeper mechanistic understanding of critical factors and pathways. PMID:22530743

  13. A novel radiographic targeting guide for percutaneous placement of transfacet screws in the cervical spine with limited fluoroscopy: A cadaveric feasibility study

    PubMed Central

    Jackson, David M.; Karp, Jacqueline E.; O'Brien, Joseph R.; Anderson, D. Greg; Gelb, Daniel E.; Ludwig, Steven C.

    2012-01-01

    Background We describe a technique for percutaneous transfacet screw placement in the cervical spine without the need for lateral-view fluoroscopy. Methods Previously established articular pillar morphometry was used to define the ideal trajectory for transfacet screw placement in the subaxial cervical spine. A unique targeting guide was developed to allow placement of Kirschner wires across the facet joint at 90° without the guidance of lateral-view fluoroscopy. Kirschner wires and cannulated screws were placed percutaneously in 7 cadaveric specimens. Placement of instrumentation was performed entirely under modified anteroposterior-view fluoroscopy. All specimens were assessed for acceptable screw placement by 2 fellowship-trained orthopaedic spine surgeons using computed tomography. Open dissection was used to confirm radiographic interpretation. Acceptable placement was defined as a screw crossing the facet joint, achieving purchase in the inferior and superior articular processes, and not violating critical structures. Malposition was defined as a violation of the transverse foramen, spinal canal, or nerve root or inadequate fixation. Results A total of 48 screws were placed. Placement of 45 screws was acceptable. The 3 instances of screw malposition included a facet fracture, a facet distraction, and a C6-7 screw contacting the C7 nerve root in a specimen with a small C7 superior articular process. Conclusions Our data show that with the appropriate radiographic technique and a targeting guide, percutaneous transfacet screws can be safely placed at C3-7 without the need for lateral-view fluoroscopy during the targeting phase. Because of the variable morphometry of the C7 lateral mass, however, care must be taken when placing a transfacet screw at C6-7. Clinical Relevance This study describes a technique that has the potential to provide a less invasive strategy for posterior instrumentation of the cervical spine. Further investigation is needed before this

  14. Schedule optimization for IR detection of buried targets

    NASA Astrophysics Data System (ADS)

    Derzko, Zenon; Eylander, John B.; Broach, J. Thomas

    2012-06-01

    Schedule optimization of air platforms for IR sensors is a priority because of 1) the time sensitive nature of the IR detection of buried targets, 2) limited air platform assets, and 3) limited bandwidth for live-feed video. Scheduling optimization for airborne IR sensors depends on transient meteorological predictions, transient soil properties, target type and depth. This work involves using predictions from the Weather Research and Forecasting (WRF) model, a regional weather model, as input to the Countermine Computational Test Bed (CTB), a 3D finite element model that accounts for coupled heat and moisture transfer in soil and targets. The result is a continuous 2-day optimized schedule for airborne IR assets. In this paper, a 2-day optimized schedule for an airborne IR sensor asset is demonstrated for a single geographical location with a buried target. Transient physical surface and subsurface soil temperatures are presented as well as the phase-shifted, transient thermal response of the target.

  15. Optimal sensor placement for large structures using the nearest neighbour index and a hybrid swarm intelligence algorithm

    NASA Astrophysics Data System (ADS)

    Lian, Jijian; He, Longjun; Ma, Bin; Li, Huokun; Peng, Wenxiang

    2013-09-01

    Research on optimal sensor placement (OSP) has become very important due to the need to obtain effective testing results with limited testing resources in health monitoring. In this study, a new methodology is proposed to select the best sensor locations for large structures. First, a novel fitness function derived from the nearest neighbour index is proposed to overcome the drawbacks of the effective independence method for OSP for large structures. This method maximizes the contribution of each sensor to modal observability and simultaneously avoids the redundancy of information between the selected degrees of freedom. A hybrid algorithm combining the improved discrete particle swarm optimization (DPSO) with the clonal selection algorithm is then implemented to optimize the proposed fitness function effectively. Finally, the proposed method is applied to an arch dam for performance verification. The results show that the proposed hybrid swarm intelligence algorithm outperforms a genetic algorithm with decimal two-dimension array encoding and DPSO in the capability of global optimization. The new fitness function is advantageous in terms of sensor distribution and ensuring a well-conditioned information matrix and orthogonality of modes, indicating that this method may be used to provide guidance for OSP in various large structures.

  16. Swarm intelligence algorithms for integrated optimization of piezoelectric actuator and sensor placement and feedback gains

    NASA Astrophysics Data System (ADS)

    Dutta, Rajdeep; Ganguli, Ranjan; Mani, V.

    2011-10-01

    Swarm intelligence algorithms are applied for optimal control of flexible smart structures bonded with piezoelectric actuators and sensors. The optimal locations of actuators/sensors and feedback gain are obtained by maximizing the energy dissipated by the feedback control system. We provide a mathematical proof that this system is uncontrollable if the actuators and sensors are placed at the nodal points of the mode shapes. The optimal locations of actuators/sensors and feedback gain represent a constrained non-linear optimization problem. This problem is converted to an unconstrained optimization problem by using penalty functions. Two swarm intelligence algorithms, namely, Artificial bee colony (ABC) and glowworm swarm optimization (GSO) algorithms, are considered to obtain the optimal solution. In earlier published research, a cantilever beam with one and two collocated actuator(s)/sensor(s) was considered and the numerical results were obtained by using genetic algorithm and gradient based optimization methods. We consider the same problem and present the results obtained by using the swarm intelligence algorithms ABC and GSO. An extension of this cantilever beam problem with five collocated actuators/sensors is considered and the numerical results obtained by using the ABC and GSO algorithms are presented. The effect of increasing the number of design variables (locations of actuators and sensors and gain) on the optimization process is investigated. It is shown that the ABC and GSO algorithms are robust and are good choices for the optimization of smart structures.

  17. Single-Command Approach and Instrument Placement by a Robot on a Target

    NASA Technical Reports Server (NTRS)

    Huntsberger, Terrance; Cheng, Yang

    2005-01-01

    AUTOAPPROACH is a computer program that enables a mobile robot to approach a target autonomously, starting from a distance of as much as 10 m, in response to a single command. AUTOAPPROACH is used in conjunction with (1) software that analyzes images acquired by stereoscopic cameras aboard the robot and (2) navigation and path-planning software that utilizes odometer readings along with the output of the image-analysis software. Intended originally for application to an instrumented, wheeled robot (rover) in scientific exploration of Mars, AUTOAPPROACH could be adapted to terrestrial applications, notably including the robotic removal of land mines and other unexploded ordnance. A human operator generates the approach command by selecting the target in images acquired by the robot cameras. The approach path consists of multiple legs. Feature points are derived from images that contain the target and are thereafter tracked to correct odometric errors and iteratively refine estimates of the position and orientation of the robot relative to the target on successive legs. The approach is terminated when the robot attains the position and orientation required for placing a scientific instrument at the target. The workspace of the robot arm is then autonomously checked for self/terrain collisions prior to the deployment of the scientific instrument onto the target.

  18. Dexterity optimization by port placement in robot-assisted minimally invasive surgery

    NASA Astrophysics Data System (ADS)

    Selha, Shaun; Dupont, Pierre; Howe, Robert D.; Torchiana, David F.

    2002-02-01

    A computer-based algorithm has been developed which uses preoperative images to provide a surgeon with a list of feasible port triplets ranked according to tool dexterity and endoscopic view quality at each surgical site involved in a procedure. A computer simulation allows the surgeon to select from among the proposed port locations. The procedure selected for the development of the system consists of a coronary artery bypass graft (CABG). In this procedure, the interior mammary artery (IMA) is mobilized from the interior chest wall, and one end is attached to the coronary arteries to provide a new blood supply for the heart. Approximately 10-20 cm is dissected free, using blunt dissection and a harmonic scalpel or electrocautery. At present, the port placement system is being evaluated in clinical trials.

  19. Implementation of a State-Wide Guidance Program with Emphasis on Counseling, Placement, and Follow-Up for Selected Target Groups. Final Report.

    ERIC Educational Resources Information Center

    Gentry, Don K.; And Others

    A 2-year project to focus on diverse approaches to placement and followup in vocational education within Indiana included seven sub-projects funded to local educational agencies across the State and targeted to specific problems. Products of the seven sub-projects were developed to provide adaptability to secondary and postsecondary schools…

  20. Optimal placement of tuning masses for vibration reduction in helicopter rotor blades

    NASA Technical Reports Server (NTRS)

    Pritchard, Jocelyn I.; Adelman, Howard M.

    1988-01-01

    Methods are presented for the reduction of helicopter rotor blade vibration through a formal mathematical optimization technique determination of optimum tuning mass sizes and locations; these are used as design variables that are systematically changed to achieve low values of shear without large mass penalty. Matrix expressions are obtained for the modal shaping parameter and modal shear amplitude that are required for FEM structural analysis of the blade as well as the optimization formulation. Sensitivity derivatives are also obtained. Three different optimization strategies are developed and tested.

  1. Effect of laryngeal mask airway placement on the optimal site and success rate of venipuncture via the right internal jugular vein

    PubMed Central

    Liu, Huan-Qiu; Li, Xin-Bai; Zhang, Yu-Shuang; Li, Ji

    2015-01-01

    The placement of a laryngeal mask airway (LMA) changes the relative positions of the common carotid artery (CCA) and right internal jugular vein (IJV), thereby affecting venipuncture via the right IJV. Therefore, we went on to determine the optimal site for puncturing the IJV after LMA-Supreme™ placement. In this study, forty-six patients were placed with a LMA-Supreme™ (size 3 or 4), and the right IJV was punctured at either of the three points (anterior, middle or posterior point). The CCA diameters and overlap between the right IJV and CCA were recorded before and after the LMA-Supreme™ placement. Finally, the success rates of IJV puncturing at the three aforementioned points were compared. We found that the size of the LMA-Supreme™ had no effect on patient respiration during the procedure. Overlap between the right IJV and CCA at the anterior and middle points was significantly increased after size 3 LMA-Supreme™ placements; Size 4 masks decreased the CCA diameters at the middle and posterior points, and significantly increased overlap between the right IJV and CCA at all the three points; IJV punctures performed after placement of size 3 LMA-Supreme™ had higher success rate than those performed after placement of size 4 masks, and were less likely to result in accidental arterial puncture. In conclusion, our study demonstrated that placement of size 3 LMA-Supreme™ caused little change in overlapping between the right IJV and CCA and the incidence of accidental arterial puncture; particularly for punctures performed at the posterior point. Therefore, we recommend venipuncture at the posterior point after placement of a LMA-Supreme™. PMID:26550241

  2. Urokinase-Treated Antithrombogenic Drains and Optimized Drain Placement in Endoscopic Lumbar Decompressive Surgery.

    PubMed

    Nakamura, Shu; Ikeda, Shoji; Taguchi, Mitsuto

    2016-07-01

    Background Spinal epidural hematoma (SEH) frequently occurs after microendoscopic decompressive laminotomy (MEDL), and a drain may not be functioning sufficiently. Objective To reduce the incidence of SEH after MEDL. Methods  A urokinase-treated antithrombogenic drain, which is available only with a large diameter, was reduced in diameter and used after MEDL. Magnetic resonance imaging (MRI) and computed tomography (CT) were performed 36 to 48 hours after surgery. The size of the SEH was measured by MRI, and the location of the drain tip was assessed by CT scan. After imaging, the drain was removed. Results Use of the urokinase-treated antithrombogenic drain reduced the incidence of SEH. However, the drain was not adequately placed in many cases, limiting the effect of the drainage. When the urokinase-treated antithrombogenic drain was placed contralaterally to the approach side using an unsheathed endoscope, the incidence of SEH was further reduced. Conclusions The urokinase-treated antithrombogenic drain prevented thrombus-related drain obstruction. In addition, unsheathed endoscopic contralateral placement of the drain was effective for SEH prevention. PMID:26935298

  3. Accuracy and safety of targeting using intraoperative "O-arm" during placement of deep brain stimulation electrodes without electrophysiological recordings.

    PubMed

    Sharma, Mayur; Deogaonkar, Milind

    2016-05-01

    The aim of our study was to investigate the accuracy of targeting using intraoperative "O-arm" during deep brain stimulation (DBS) surgery. Intraoperative O-arm (Medtronic, Minneapolis, MN, USA) images were obtained to confirm the accuracy of placement. The difference between intended and actual target coordinates was calculated based on intraoperative images and postoperative CT scan. Euclidian vector error was obtained to estimate the directional error. Correlation of targeting error with the pneumocephalus and the deviation from the planned trajectory was also estimated. Twenty eight DBS leads (globus pallidus internus [GPi], n=13; subthalamic nucleus [STN], n=9; ventralis intermedius nucleus [VIM], n=6) were implanted in 20 patients using the stereotactic Leksell frame (Elekta AB, Stockholm, Sweden) under general anesthesia over a period of 1year. The mean age was 63.6±standard error of the mean (SEM) 15.7years and 60% of patients were males. The mean absolute difference (+SEM) between intended and actual target in x, y and z coordinates based on intraoperative CT scan was 0.65±0.09 (p=0.84), 0.58±0.08 (p=0.98), 1.13±0.10 (p=0.08), respectively, and postoperative (1month) CT scan was 0.82±0.15 (p=0.89), 0.55±0.11 (p=0.97), and 1.58±0.29 (p=0.08), respectively. The Euclidean vector error was 1.59±0.10 and 2.16±0.26 based on intraoperative and postoperative images, respectively. There was no statistically significant targeting error based on fusion of intraoperative CT images to either preoperative CT scan or MRI as registration series, the presence of pneumocephalus, deviation from planned trajectory or the anatomical target (STN versus VIM versus GPi) (p>0.05). Superficial skin infection was encountered in a single patient in this study. The mean total operating room time was 193.5±74.6 minutes. None of the patients required revision in our study. DBS leads can be implanted safely and accurately using intraoperative O-arm with a frame based targeting

  4. Optimization of shunt placement for the Norwood surgery using multi-domain modeling.

    PubMed

    Moghadam, Mahdi Esmaily; Migliavacca, Francesco; Vignon-Clementel, Irene E; Hsia, Tain-Yen; Marsden, Alison L

    2012-05-01

    An idealized systemic-to-pulmonary shunt anatomy is parameterized and coupled to a closed loop, lumped parameter network (LPN) in a multidomain model of the Norwood surgical anatomy. The LPN approach is essential for obtaining information on global changes in cardiac output and oxygen delivery resulting from changes in local geometry and physiology. The LPN is fully coupled to a custom 3D finite element solver using a semi-implicit approach to model the heart and downstream circulation. This closed loop multidomain model is then integrated with a fully automated derivative-free optimization algorithm to obtain optimal shunt geometries with variable parameters of shunt diameter, anastomosis location, and angles. Three objective functions: (1) systemic; (2) coronary; and (3) combined systemic and coronary oxygen deliveries are maximized. Results show that a smaller shunt diameter with a distal shunt-brachiocephalic anastomosis is optimal for systemic oxygen delivery, whereas a more proximal anastomosis is optimal for coronary oxygen delivery and a shunt between these two anatomies is optimal for both systemic and coronary oxygen deliveries. Results are used to quantify the origin of blood flow going through the shunt and its relationship with shunt geometry. Results show that coronary artery flow is directly related to shunt position. PMID:22757490

  5. A Topography Analysis Incorporated Optimization Method for the Selection and Placement of Best Management Practices

    PubMed Central

    Shen, Zhenyao; Chen, Lei; Xu, Liang

    2013-01-01

    Best Management Practices (BMPs) are one of the most effective methods to control nonpoint source (NPS) pollution at a watershed scale. In this paper, the use of a topography analysis incorporated optimization method (TAIOM) was proposed, which integrates topography analysis with cost-effective optimization. The surface status, slope and the type of land use were evaluated as inputs for the optimization engine. A genetic algorithm program was coded to obtain the final optimization. The TAIOM was validated in conjunction with the Soil and Water Assessment Tool (SWAT) in the Yulin watershed in Southwestern China. The results showed that the TAIOM was more cost-effective than traditional optimization methods. The distribution of selected BMPs throughout landscapes comprising relatively flat plains and gentle slopes, suggests the need for a more operationally effective scheme, such as the TAIOM, to determine the practicability of BMPs before widespread adoption. The TAIOM developed in this study can easily be extended to other watersheds to help decision makers control NPS pollution. PMID:23349917

  6. Optimal Needle Placement for Extensor Hallucis Longus Muscle: A Cadaveric Study

    PubMed Central

    2016-01-01

    Objective To determine the midpoint (MD) of extensor hallucis longus muscle (EHL) and compare the accuracy of different needle electromyography (EMG) insertion techniques through cadaver dissection. Methods Thirty-eight limbs of 19 cadavers were dissected. The MD of EHL was marked at the middle of the musculotendinous junction and proximal origin of EHL. Three different needle insertion points of EHL were marked following three different textbooks: M1, 3 fingerbreadths above bimalleolar line (BML); M2, junction between the middle and lower third of tibia; M3, 15 cm proximal to the lower border of both malleoli. The distance from BML to MD (BML_MD), and the difference between 3 different points (M1–3) and MD were measured (designated D1, D2, and D3, respectively). The lower leg length (LL) was measured from BML to top of medial condyle of tibia. Results The median value of LL was 34.5 cm and BML_MD was 12.0 cm. The percentage of BML_MD to LL was 35.1%. D1, D2, and D3 were 7.0, 0.9, and 3.0 cm, respectively. D2 was the shortest, meaning needle placement following technique by Lee and DeLisa was closest to the actual midpoint of EHL. Conclusion The MD of EHL is approximately 12 cm above BML, and about distal 35% of lower leg length. Technique that recommends placing the needle at distal two-thirds of the lower leg (M2) is the most accurate method since the point was closest to muscle belly of EHL.

  7. Intraoperative MRI for optimizing electrode placement for deep brain stimulation of the subthalamic nucleus in Parkinson disease.

    PubMed

    Cui, Zhiqiang; Pan, Longsheng; Song, Huifang; Xu, Xin; Xu, Bainan; Yu, Xinguang; Ling, Zhipei

    2016-01-01

    OBJECT The degree of clinical improvement achieved by deep brain stimulation (DBS) is largely dependent on the accuracy of lead placement. This study reports on the evaluation of intraoperative MRI (iMRI) for adjusting deviated electrodes to the accurate anatomical position during DBS surgery and acute intracranial changes. METHODS Two hundred and six DBS electrodes were implanted in the subthalamic nucleus (STN) in 110 patients with Parkinson disease. All patients underwent iMRI after implantation to define the accuracy of lead placement. Fifty-six DBS electrode positions in 35 patients deviated from the center of the STN, according to the result of the initial postplacement iMRI scans. Thus, we adjusted the electrode positions for placement in the center of the STN and verified this by means of second or third iMRI scans. Recording was performed in adjusted parameters in the x-, y-, and z-axes. RESULTS Fifty-six (27%) of 206 DBS electrodes were adjusted as guided by iMRI. Electrode position was adjusted on the basis of iMRI 62 times. The sum of target coordinate adjustment was -0.5 mm in the x-axis, -4 mm in the y-axis, and 15.5 mm in the z-axis; the total of distance adjustment was 74.5 mm in the x-axis, 88 mm in the y-axis, and 42.5 mm in the z-axis. After adjustment with the help of iMRI, all electrodes were located in the center of the STN. Intraoperative MRI revealed 2 intraparenchymal hemorrhages in 2 patients, brain shift in all patients, and leads penetrating the lateral ventricle in 3 patients. CONCLUSIONS The iMRI technique can guide surgeons as they adjust deviated electrodes to improve the accuracy of implanting the electrodes into the correct anatomical position. The iMRI technique can also immediately demonstrate acute changes such as hemorrhage and brain shift during DBS surgery. PMID:26274983

  8. A small perturbation based optimization approach for the frequency placement of high aspect ratio wings

    NASA Astrophysics Data System (ADS)

    Goltsch, Mandy

    Design denotes the transformation of an identified need to its physical embodiment in a traditionally iterative approach of trial and error. Conceptual design plays a prominent role but an almost infinite number of possible solutions at the outset of design necessitates fast evaluations. The corresponding practice of empirical equations and low fidelity analyses becomes obsolete in the light of novel concepts. Ever increasing system complexity and resource scarcity mandate new approaches to adequately capture system characteristics. Contemporary concerns in atmospheric science and homeland security created an operational need for unconventional configurations. Unmanned long endurance flight at high altitudes offers a unique showcase for the exploration of new design spaces and the incidental deficit of conceptual modeling and simulation capabilities. Structural and aerodynamic performance requirements necessitate light weight materials and high aspect ratio wings resulting in distinct structural and aeroelastic response characteristics that stand in close correlation with natural vibration modes. The present research effort evolves around the development of an efficient and accurate optimization algorithm for high aspect ratio wings subject to natural frequency constraints. Foundational corner stones are beam dimensional reduction and modal perturbation redesign. Local and global analyses inherent to the former suggest corresponding levels of local and global optimization. The present approach departs from this suggestion. It introduces local level surrogate models to capacitate a methodology that consists of multi level analyses feeding into a single level optimization. The innovative heart of the new algorithm originates in small perturbation theory. A sequence of small perturbation solutions allows the optimizer to make incremental movements within the design space. It enables a directed search that is free of costly gradients. System matrices are decomposed

  9. Optimal sensor placement in the base-isolated structures subjected to near-fault earthquakes using a novel TTFD approach

    NASA Astrophysics Data System (ADS)

    Sadat Shokouhi, Seyed Kazem; Dolatshah, Azam; Vosoughifar, Hamid Reza; Rahnavard, Yousef; Dowlatshahi, Bijan

    2013-04-01

    As a consequence of the ground motions during near-field earthquakes, stronger design and controlling damages of vital structures should be significantly paid attention. Seismic base isolation system is an effective approach for passive protection of structure when an earthquake occurs, because it modifies the structural global response and improves seismic performance. In this study, a Base-Isolated (BI) structure was modeled using Finite Element Method (FEM) in which modal and nonlinear time-history analyses were undertaken using the seismic scaled records of near-fault earthquakes. Furthermore, three various Optimal Sensor Placement (OSP) algorithms were used and Genetic Algorithm (GA) was selected to act as the solution of the optimization formulation. A novel numerical approach was proposed for OSP which was called Transformed Time-history to Frequency Domain (TTFD) algorithm. The TTFD method uses nonlinear time-history analysis results as an exact seismic response despite the common OSP algorithms which utilize modal analysis results. Results show that with a proper OSP method for Structural Health Monitoring (SHM) can detect the weak points of BI structures.

  10. Optimization of Sizing and Placement of Energy Storage Systems on an Islanded Grid with High Penetration of Renewables

    NASA Astrophysics Data System (ADS)

    Lim, M. M.

    This thesis seeks to find an optimized energy storage system (ESS) solution that reduces the effects of power variations and fluctuations from renewable energy sources like wind and solar. This study focuses on the effects of renewables at penetration levels larger than 20% for an isolated power grid. This optimized energy storage solution includes sizing the ESS appropriately while taking into account the economic cost of deploying the ESS. The ideal placement of the ESS on this grid seeks to reduce any impact on grid transmission congestion due to the ESS. Two configurations of the grid were modeled; the first is a simple load-frequency control model of the grid that only examines the effect of active power fluctuations from the renewables on the grid. The other model uses a one-line transmission line model of the isolated grid to model the transmission congestion in the grid. Modeling has shown that ESS systems are capable of reducing the frequency variations and reducing power fluctuations, however there is a trade off in economic cost.

  11. Optimal placement of tuning masses for vibration reduction in helicopter rotor blades

    NASA Technical Reports Server (NTRS)

    Pritchard, Jocelyn I.; Adelman, Howard M.

    1988-01-01

    Described are methods for reducing vibration in helicopter rotor blades by determining optimum sizes and locations of tuning masses through formal mathematical optimization techniques. An optimization procedure is developed which employs the tuning masses and corresponding locations as design variables which are systematically changed to achieve low values of shear without a large mass penalty. The finite-element structural analysis of the blade and the optimization formulation require development of discretized expressions for two performance parameters: modal shaping parameter and modal shear amplitude. Matrix expressions for both quantities and their sensitivity derivatives are developed. Three optimization strategies are developed and tested. The first is based on minimizing the modal shaping parameter which indirectly reduces the modal shear amplitudes corresponding to each harmonic of airload. The second strategy reduces these amplitudes directly, and the third strategy reduces the shear as a function of time during a revolution of the blade. The first strategy works well for reducing the shear for one mode responding to a single harmonic of the airload, but has been found in some cases to be ineffective for more than one mode. The second and third strategies give similar results and show excellent reduction of the shear with a low mass penalty.

  12. Optimal Placement of Irradiation Sources in the Planning of Radiotherapy: Mathematical Models and Methods of Solving

    PubMed Central

    Blyuss, Oleg; Koriashkina, Larysa; Kiseleva, Elena; Molchanov, Robert

    2015-01-01

    This paper proposes and analyses a mathematical model for the problem of distribution of a finite number of irradiation sources during radiotherapy in continuous environments to maximize the minimal cumulative effects. A new algorithm based on nondifferentiable optimization techniques has been developed to solve this problem. PMID:26543492

  13. Optimizing biologically targeted clinical trials for neurofibromatosis

    PubMed Central

    Gutmann, David H; Blakeley, Jaishri O; Korf, Bruce R; Packer, Roger J

    2014-01-01

    Introduction The neurofibromatoses (neurofibromatosis type 1, NF1 and neurofibromatosis type 2, NF2) comprise the most common inherited conditions in which affected children and adults develop tumors of the central and peripheral nervous system. In this review, the authors discuss how the establishment of the Neurofibromatosis Clinical Trials Consortium (NFCTC) has positively impacted on the design and execution of treatment studies for individuals with NF1 and NF2. Areas covered Using an extensive PUBMED search in collaboration with select NFCTC members expert in distinct NF topics, the authors discuss the clinical features of NF1 and NF2, the molecular biology of the NF1 and NF2 genes, the development and application of clinically relevant Nf1 and Nf2 genetically engineered mouse models and the formation of the NFCTC to enable efficient clinical trial design and execution. Expert opinion The NFCTC has resulted in a more seamless integration of mouse preclinical and human clinical trials efforts. Leveraging emerging enabling resources, current research is focused on identifying subtypes of tumors in NF1 and NF2 to deliver the most active compounds to the patients most likely to respond to the targeted therapy. PMID:23425047

  14. Characteristics and optimization of radar target with plasma cover

    NASA Astrophysics Data System (ADS)

    Yang, Ying-ying; Zhao, Wei-fang; Wang, Wen-ting; Yi, Xiao-jing; Ji, Jun-wen; Lin, Xue-chun

    2013-09-01

    In this paper, we investigated the characteristic of radar target, the spherical and the pyramidal missile warheads, and compared the RCS and performance of the targets with and without the cover of the plasma metamaterials. Numerical simulation is obtained by the numerical calculation Finite-difference time-domain method (FDTD). The parameters of plasmonic structures as a metamaterial cloak was designed and optimized. The relationship between the parameters of the cloak and the corresponding electromagnetic characteristic of the target are analyzed by the simulation and discussion in broadband radar signals. After optimization, the plasma cover could attenuate 40 dBsm of the radar cross section (RCS) of the targets maximally. The result shows that the anomalous phenomenon of cloaking and stealth effects induced by plasma materials for the radar target, which might have potential application of military affairs.

  15. Optimal Well Placement for Enhanced Degradation during In Situ Groundwater Remediation

    NASA Astrophysics Data System (ADS)

    Greene, J. A.; Neupauer, R.; Piscopo, A. N.; Kasprzyk, J. R.

    2015-12-01

    Active spreading strategies have been developed to enhance contaminant degradation during in situ remediation by increasing contact of the injected treatment chemical with the contaminant plume. The contact between these reactants is increased by strategically injecting and extracting water at wells surrounding the plume to reconfigure the treatment chemical and contaminant plume in the aquifer, which leads to enhanced contaminant degradation. The distance and orientation of the wells relative to the contaminant plume affects the ability of active spreading strategies to efficiently degrade contaminant. In this study, we use a multi-objective evolutionary algorithm to optimize the distance and orientation of wells for both circular and elliptical contaminant plumes with uniform and Gaussian initial concentration distributions. The optimization yields results that maximize the amount of degradation achieved during in situ remediation while minimizing any extraction of treatment chemical.

  16. Optimal placement of trailing-edge flaps for helicopter vibration reduction using response surface methods

    NASA Astrophysics Data System (ADS)

    Viswamurthy, S. R.; Ganguli, Ranjan

    2007-03-01

    This study aims to determine optimal locations of dual trailing-edge flaps to achieve minimum hub vibration levels in a helicopter, while incurring low penalty in terms of required trailing-edge flap control power. An aeroelastic analysis based on finite elements in space and time is used in conjunction with an optimal control algorithm to determine the flap time history for vibration minimization. The reduced hub vibration levels and required flap control power (due to flap motion) are the two objectives considered in this study and the flap locations along the blade are the design variables. It is found that second order polynomial response surfaces based on the central composite design of the theory of design of experiments describe both objectives adequately. Numerical studies for a four-bladed hingeless rotor show that both objectives are more sensitive to outboard flap location compared to the inboard flap location by an order of magnitude. Optimization results show a disjoint Pareto surface between the two objectives. Two interesting design points are obtained. The first design gives 77 percent vibration reduction from baseline conditions (no flap motion) with a 7 percent increase in flap power compared to the initial design. The second design yields 70 percent reduction in hub vibration with a 27 percent reduction in flap power from the initial design.

  17. On actuator placement for robust time-optimal control of uncertain flexible spacecraft

    NASA Technical Reports Server (NTRS)

    Wie, Bong; Sinha, Ravi; Liu, Qiang

    1992-01-01

    The problem of computing open-loop, on-off jet firing logic for flexible spacecraft in the face of plant modeling uncertainty is investigated. The primary control objective is to achieve a fast maneuvering time with a minimum of structural vibrations during and/or after a maneuver. This paper is also concerned with the problem of selecting a proper pair of jets for practical trade-offs among the maneuvering time, fuel consumption, structural mode excitation, and performance robustness. A time-optimal control problem subject to parameter robustness constraints is formulated. A three-mass-spring model of flexible spacecraft with a rigid-body mode and two flexible modes is used to illustrate the concept.

  18. Keyword: Placement

    ERIC Educational Resources Information Center

    Cassuto, Leonard

    2012-01-01

    The practical goal of graduate education is placement of graduates. But what does "placement" mean? Academics use the word without thinking much about it. "Placement" is a great keyword for the graduate-school enterprise. For one thing, its meaning certainly gives a purpose to graduate education. Furthermore, the word is a portal into the way of…

  19. The Optimal Placement of Sutures in All-inside Repair of Meniscocapsular Separation

    PubMed Central

    Tiftikci, Uğur; Serbest, Sancar

    2016-01-01

    Background: The aim of this study was to show the effects on the meniscus of repair applied from the femoral, the femoral-tibial and the tibial surfaces. Methods: In the treatment of meniscocapsular separation, although the accepted gold standard technique in the past was the inside-out suture technique, the current treatment method is all-inside repair methods. The all-inside techniques include the hook method and applications with a meniscus suture device. The hook method is difficult with a steep learning curve. In meniscus repair applied with the all-inside meniscus devices, the application of the suture can change the anatomic structure and position of the meniscus. Results: The suturing method applied from the tibial section of the meniscus does not disrupt the anatomic position of the meniscus in meniscocapsular separation. Thus, the optimum conditions are provided for restoration of the functions of the meniscus. Conclusion: The optimal repair in meniscocapsular separations can be considered to be that made with sutures from the tibial section of the meniscus. This technique may be helpful in obtaining better clinical results. PMID:27347236

  20. The computational optimization of indirect-driven ICF targets

    SciTech Connect

    Lykov, V.A.; Avrorin, E.N.; Karlykhanov, N.G.; Chernyakov, V.E.; Kozmanov, M.Y.; Murashkina, V.A.; Kandiev, Y.Z.

    1996-05-01

    The results of the ICF indirect-driven targets optimization performed by ZARYA/ERA code for a better insight into the requirements imposed on both target designs and hohlraum drive temperature to gain the ignition with laser of minimum power are presented. Two modification of cryogenic shell targets for hohlraum drive temperatures in the range of 0.25{endash}0.38 keV are proposed for the ignition. The 500 TW lasers are needed to perform such investigations. {copyright} {ital 1996 American Institute of Physics.}

  1. On-road experiment to assess drivers' detection of roadside targets as a function of headlight system, target placement, and target reflectance.

    PubMed

    Reagan, Ian J; Brumbelow, Matt; Frischmann, Tim

    2015-03-01

    Adaptive headlights swivel with steering input to keep the beams on the roadway as drivers negotiate curves. To assess the effects of this feature on driver's visual performance, a field experiment was conducted at night on a rural, unlit, and unlined two-lane road during which 20 adult participant drivers searched a set of 60 targets. High- (n=30) and low- (n=30) reflectance targets were evenly distributed on straight road sections and on the inside or outside of curves. Participants completed three target detection trials: once with adaptive high-intensity discharge (HID) headlights, once with fixed HID headlights, and once with fixed halogen headlights. Results indicated the adaptive HID headlights helped drivers detect targets that were most difficult to see (low reflectance) at the points in curves found by other researchers to be most crucial for successful navigation (inside apex). For targets placed on straight stretches of road or on the outside of curves, the adaptive feature provided no significant improvement in target detection. However, the pattern of results indicate that HID lamps whether fixed or adaptive improved target detection somewhat, suggesting that part of the real world crash reduction measured for this adaptive system (Highway Loss Data Institute (HLDI), 2012a) may be due to the differences in the light source (HID vs. halogen). Depending on the scenario, the estimated benefits to driver response time associated with the tested adaptive (swiveling HID) headlights ranged from 200 to 380ms compared with the fixed headlight systems tested. PMID:25603548

  2. Optimization of OT-MACH Filter Generation for Target Recognition

    NASA Technical Reports Server (NTRS)

    Johnson, Oliver C.; Edens, Weston; Lu, Thomas T.; Chao, Tien-Hsin

    2009-01-01

    An automatic Optimum Trade-off Maximum Average Correlation Height (OT-MACH) filter generator for use in a gray-scale optical correlator (GOC) has been developed for improved target detection at JPL. While the OT-MACH filter has been shown to be an optimal filter for target detection, actually solving for the optimum is too computationally intensive for multiple targets. Instead, an adaptive step gradient descent method was tested to iteratively optimize the three OT-MACH parameters, alpha, beta, and gamma. The feedback for the gradient descent method was a composite of the performance measures, correlation peak height and peak to side lobe ratio. The automated method generated and tested multiple filters in order to approach the optimal filter quicker and more reliably than the current manual method. Initial usage and testing has shown preliminary success at finding an approximation of the optimal filter, in terms of alpha, beta, gamma values. This corresponded to a substantial improvement in detection performance where the true positive rate increased for the same average false positives per image.

  3. Optimization of bioenergy crop selection and placement based on a stream health indicator using an evolutionary algorithm.

    PubMed

    Herman, Matthew R; Nejadhashemi, A Pouyan; Daneshvar, Fariborz; Abouali, Mohammad; Ross, Dennis M; Woznicki, Sean A; Zhang, Zhen

    2016-10-01

    The emission of greenhouse gases continues to amplify the impacts of global climate change. This has led to the increased focus on using renewable energy sources, such as biofuels, due to their lower impact on the environment. However, the production of biofuels can still have negative impacts on water resources. This study introduces a new strategy to optimize bioenergy landscapes while improving stream health for the region. To accomplish this, several hydrological models including the Soil and Water Assessment Tool, Hydrologic Integrity Tool, and Adaptive Neruro Fuzzy Inference System, were linked to develop stream health predictor models. These models are capable of estimating stream health scores based on the Index of Biological Integrity. The coupling of the aforementioned models was used to guide a genetic algorithm to design watershed-scale bioenergy landscapes. Thirteen bioenergy managements were considered based on the high probability of adaptation by farmers in the study area. Results from two thousand runs identified an optimum bioenergy crops placement that maximized the stream health for the Flint River Watershed in Michigan. The final overall stream health score was 50.93, which was improved from the current stream health score of 48.19. This was shown to be a significant improvement at the 1% significant level. For this final bioenergy landscape the most often used management was miscanthus (27.07%), followed by corn-soybean-rye (19.00%), corn stover-soybean (18.09%), and corn-soybean (16.43%). The technique introduced in this study can be successfully modified for use in different regions and can be used by stakeholders and decision makers to develop bioenergy landscapes that maximize stream health in the area of interest. PMID:27420165

  4. An Optimal Initial Guess Generator for Entry Interface Targeters

    NASA Technical Reports Server (NTRS)

    Senent, Juan S.

    2009-01-01

    If a pure numerical iterative approach is used, targeting entry interface (EI) conditions for nominal and abort return trajectories or for correction maneuvers can be computationally expensive. This paper describes an algorithm to obtain an optimal impulsive maneuver that generates a trajectory satisfying a set of EI targets: inequality constraints on longitude, latitude and azimuth and a fixed flight-path angle. Most of the calculations require no iterations, making it suitable for real-time applications or large trade studies. This algorithm has been used to generate initial guesses for abort trajectories during Earth-Moon transfers.

  5. Target scattering estimation in clutter with polarization optimization

    NASA Astrophysics Data System (ADS)

    Cheng, Xu; Shi, Longfei; Chang, Yuliang; Li, Yongzhen; Wang, Xuesong

    2015-12-01

    In this paper, we propose an adaptive waveform polarization method for the estimation of target scattering matrix in the presence of clutter. The proposed sequential algorithm, based on the concept of sequential minimum mean square error (MSE) estimation, to determine the coefficients of the scattering matrix, guarantees the convergence and the resulting computational complexity is linear with the number of iterations. The effectiveness of the proposed method is validated through numerical results, underlining the performance improvement given by joint transmission and reception (Tx/Rx) polarization optimization for the scalar system. Also, the results show that the vector system with transmission polarization optimization provides a comparative performance as the scalar measurement system employing joint Tx/Rx polarization optimization. Less computation burden highlights the advantage of the former mode.

  6. Optimized shapes of magnetic arrays for drug targeting applications

    NASA Astrophysics Data System (ADS)

    Barnsley, Lester C.; Carugo, Dario; Stride, Eleanor

    2016-06-01

    Arrays of permanent magnet elements have been utilized as light-weight, inexpensive sources for applying external magnetic fields in magnetic drug targeting applications, but they are extremely limited in the range of depths over which they can apply useful magnetic forces. In this paper, designs for optimized magnet arrays are presented, which were generated using an optimization routine to maximize the magnetic force available from an arbitrary arrangement of magnetized elements, depending on a set of design parameters including the depth of targeting (up to 50 mm from the magnet) and direction of force required. A method for assembling arrays in practice is considered, quantifying the difficulty of assembly and suggesting a means for easing this difficulty without a significant compromise to the applied field or force. Finite element simulations of in vitro magnetic retention experiments were run to demonstrate the capability of a subset of arrays to retain magnetic microparticles against flow. The results suggest that, depending on the choice of array, a useful proportion of particles (more than 10% ) could be retained at flow velocities up to 100 mm s‑1 or to depths as far as 50 mm from the magnet. Finally, the optimization routine was used to generate a design for a Halbach array optimized to deliver magnetic force to a depth of 50 mm inside the brain.

  7. Using Heuristic Algorithms to Optimize Observing Target Sequences

    NASA Astrophysics Data System (ADS)

    Sosnowska, D.; Ouadahi, A.; Buchschacher, N.; Weber, L.; Pepe, F.

    2014-05-01

    The preparation of observations is normally carried out at the telescope by the visiting observer. In order to help the observer, we propose several algorithms to automatically optimize the sequence of targets. The optimization consists of assuring that all the chosen targets are observable within the given time interval, and to find their best execution order in terms of the observation quality and the shortest telescope displacement time. Since an exhaustive search is too expensive in time, we researched heuristic algorithms, specifically: Min-Conflict, Non-Sorting Genetic Algorithms and Simulated Annealing. Multiple metaheuristics are used in parallel to swiftly give an approximation of the best solution, with all the constraints satisfied and the total execution time minimized. The optimization process has a duration on the order of tens of seconds, allowing for quick re-adaptation in case of changing atmospheric conditions. The graphical user interface allows the user to control the parameters of the optimization process. Therefore, the search can be adjusted in real time. The module was coded in a way to allow easily the addition of new constraints, and thus ensure its compatibility with different instruments. For now, the application runs as a plug-in to the observation preparation tool called New Short Term Scheduler, which is used on three spectrographs dedicated to the exoplanets search: HARPS at the La Silla observatory, HARPS North at the La Palma observatory and SOPHIE at the Observatoire de Haute-Provence.

  8. Modeling of delamination in carbon/epoxy composite laminates under four point bending for damage detection and sensor placement optimization

    NASA Astrophysics Data System (ADS)

    Adu, Stephen Aboagye

    composite coupon under simply supported boundary conditions. Theoretically calculated bending stiffness's and maximum deflection were compared with that of the experimental case and the numerical. After the FEA model was properly benchmarked with test data and exact solution, data obtained from the FEM model were used for sensor placement optimization.

  9. Large-scale optimal sensor array management for target tracking

    NASA Astrophysics Data System (ADS)

    Tharmarasa, Ratnasingham; Kirubarajan, Thiagalingam; Hernandez, Marcel L.

    2004-01-01

    Large-scale sensor array management has applications in a number of target tracking problems. For example, in ground target tracking, hundreds or even thousands of unattended ground sensors (UGS) may be dropped over a large surveillance area. At any one time it may then only be possible to utilize a very small number of the available sensors at the fusion center because of bandwidth limitations. A similar situation may arise in tracking sea surface or underwater targets using a large number of sonobuoys. The general problem is then to select a subset of the available sensors in order to optimize tracking performance. The Posterior Cramer-Rao Lower Bound (PCRLB), which quantifies the obtainable accuracy of target state estimation, is used as the basis for network management. In a practical scenario with even hundreds of sensors, the number of possible sensor combinations would make it impossible to enumerate all possibilities in real-time. Efficient local (or greedy) search techniques must then be used to make the computational load manageable. In this paper we introduce an efficient search strategy for selecting a subset of the sensor array for use during each sensor change interval in multi-target tracking. Simulation results illustrating the performance of the sensor array manager are also presented.

  10. Large-scale optimal sensor array management for target tracking

    NASA Astrophysics Data System (ADS)

    Tharmarasa, Ratnasingham; Kirubarajan, Thiagalingam; Hernandez, Marcel L.

    2003-12-01

    Large-scale sensor array management has applications in a number of target tracking problems. For example, in ground target tracking, hundreds or even thousands of unattended ground sensors (UGS) may be dropped over a large surveillance area. At any one time it may then only be possible to utilize a very small number of the available sensors at the fusion center because of bandwidth limitations. A similar situation may arise in tracking sea surface or underwater targets using a large number of sonobuoys. The general problem is then to select a subset of the available sensors in order to optimize tracking performance. The Posterior Cramer-Rao Lower Bound (PCRLB), which quantifies the obtainable accuracy of target state estimation, is used as the basis for network management. In a practical scenario with even hundreds of sensors, the number of possible sensor combinations would make it impossible to enumerate all possibilities in real-time. Efficient local (or greedy) search techniques must then be used to make the computational load manageable. In this paper we introduce an efficient search strategy for selecting a subset of the sensor array for use during each sensor change interval in multi-target tracking. Simulation results illustrating the performance of the sensor array manager are also presented.

  11. Optimizing Interacting Potentials to Form Targeted Materials Structures

    SciTech Connect

    Torquato, Salvatore

    2015-09-28

    Conventional applications of the principles of statistical mechanics (the "forward" problems), start with particle interaction potentials, and proceed to deduce local structure and macroscopic properties. Other applications (that may be classified as "inverse" problems), begin with targeted configurational information, such as low-order correlation functions that characterize local particle order, and attempt to back out full-system configurations and/or interaction potentials. To supplement these successful experimental and numerical "forward" approaches, we have focused on inverse approaches that make use of analytical and computational tools to optimize interactions for targeted self-assembly of nanosystems. The most original aspect of our work is its inherently inverse approach: instead of predicting structures that result from given interaction potentials among particles, we determine the optimal potential that most robustly stabilizes a given target structure subject to certain constraints. Our inverse approach could revolutionize the manner in which materials are designed and fabricated. There are a number of very tangible properties (e.g. zero thermal expansion behavior), elastic constants, optical properties for photonic applications, and transport properties.

  12. Autonomous Optimization of Targeted Stimulation of Neuronal Networks

    PubMed Central

    Kumar, Sreedhar S.; Wülfing, Jan; Okujeni, Samora; Boedecker, Joschka; Riedmiller, Martin

    2016-01-01

    Driven by clinical needs and progress in neurotechnology, targeted interaction with neuronal networks is of increasing importance. Yet, the dynamics of interaction between intrinsic ongoing activity in neuronal networks and their response to stimulation is unknown. Nonetheless, electrical stimulation of the brain is increasingly explored as a therapeutic strategy and as a means to artificially inject information into neural circuits. Strategies using regular or event-triggered fixed stimuli discount the influence of ongoing neuronal activity on the stimulation outcome and are therefore not optimal to induce specific responses reliably. Yet, without suitable mechanistic models, it is hardly possible to optimize such interactions, in particular when desired response features are network-dependent and are initially unknown. In this proof-of-principle study, we present an experimental paradigm using reinforcement-learning (RL) to optimize stimulus settings autonomously and evaluate the learned control strategy using phenomenological models. We asked how to (1) capture the interaction of ongoing network activity, electrical stimulation and evoked responses in a quantifiable ‘state’ to formulate a well-posed control problem, (2) find the optimal state for stimulation, and (3) evaluate the quality of the solution found. Electrical stimulation of generic neuronal networks grown from rat cortical tissue in vitro evoked bursts of action potentials (responses). We show that the dynamic interplay of their magnitudes and the probability to be intercepted by spontaneous events defines a trade-off scenario with a network-specific unique optimal latency maximizing stimulus efficacy. An RL controller was set to find this optimum autonomously. Across networks, stimulation efficacy increased in 90% of the sessions after learning and learned latencies strongly agreed with those predicted from open-loop experiments. Our results show that autonomous techniques can exploit

  13. Autonomous Optimization of Targeted Stimulation of Neuronal Networks.

    PubMed

    Kumar, Sreedhar S; Wülfing, Jan; Okujeni, Samora; Boedecker, Joschka; Riedmiller, Martin; Egert, Ulrich

    2016-08-01

    Driven by clinical needs and progress in neurotechnology, targeted interaction with neuronal networks is of increasing importance. Yet, the dynamics of interaction between intrinsic ongoing activity in neuronal networks and their response to stimulation is unknown. Nonetheless, electrical stimulation of the brain is increasingly explored as a therapeutic strategy and as a means to artificially inject information into neural circuits. Strategies using regular or event-triggered fixed stimuli discount the influence of ongoing neuronal activity on the stimulation outcome and are therefore not optimal to induce specific responses reliably. Yet, without suitable mechanistic models, it is hardly possible to optimize such interactions, in particular when desired response features are network-dependent and are initially unknown. In this proof-of-principle study, we present an experimental paradigm using reinforcement-learning (RL) to optimize stimulus settings autonomously and evaluate the learned control strategy using phenomenological models. We asked how to (1) capture the interaction of ongoing network activity, electrical stimulation and evoked responses in a quantifiable 'state' to formulate a well-posed control problem, (2) find the optimal state for stimulation, and (3) evaluate the quality of the solution found. Electrical stimulation of generic neuronal networks grown from rat cortical tissue in vitro evoked bursts of action potentials (responses). We show that the dynamic interplay of their magnitudes and the probability to be intercepted by spontaneous events defines a trade-off scenario with a network-specific unique optimal latency maximizing stimulus efficacy. An RL controller was set to find this optimum autonomously. Across networks, stimulation efficacy increased in 90% of the sessions after learning and learned latencies strongly agreed with those predicted from open-loop experiments. Our results show that autonomous techniques can exploit quantitative

  14. A Constrained Differential Evolution Algorithm for Reservoir Management: Optimal Placement and Control of Wells for Geological Carbon Storage with Uncertainty in Reservoir Properties

    NASA Astrophysics Data System (ADS)

    Cihan, A.; Birkholzer, J. T.; Bianchi, M.

    2014-12-01

    Injection of large volume of CO2 into deep geological reservoirs for geologic carbon sequestration (GCS) is expected to cause significant pressure perturbations in subsurface. Large-scale pressure increases in injection reservoirs during GCS operations, if not controlled properly, may limit dynamic storage capacity and increase risk of environmental impacts. The high pressure may impact caprock integrity, induce fault slippage, and cause leakage of brine and/or CO2 into shallow fresh groundwater resources. Thus, monitoring and controlling pressure buildup are critically important for environmentally safe implementation of GCS projects. Extraction of native brine during GCS operations is a pressure management approach to reduce significant pressure buildup. Extracted brine can be transferred to the surface for utilization or re-injected into overlying/underlying saline aquifers. However, pumping, transportation, treatment and disposal of extracted brine can be challenging and costly. Therefore, minimizing volume of extracted brine, while maximizing CO2 storage, is an essential objective of the pressure management with brine extraction schemes. Selection of optimal well locations and extraction rates are critical for maximizing storage and minimizing brine extraction during GCS. However, placing of injection and extraction wells is not intuitive because of heterogeneity in reservoir properties and complex reservoir geometry. Efficient computerized algorithms combining reservoir models and optimization methods are needed to make proper decisions on well locations and control parameters. This study presents a global optimization methodology for pressure management during geologic CO2 sequestration. A constrained differential evolution (CDE) algorithm is introduced for solving optimization problems involving well placement and injection/extraction control. The CDE methodology is tested and applied for realistic CO2 storage scenarios with the presence of uncertainty in

  15. Optimal Structural Design of Mannosylated Nanocarriers for Macrophage Targeting

    PubMed Central

    Chen, Peiming; Zhang, Xiaoping; Jia, Lee; Prud’homme, Robert K.; Szekely, Zoltan; Sinko, Patrick J.

    2014-01-01

    Macrophages are involved in a number of diseases, such as HIV infection/AIDS, tuberculosis, tumor development and atherosclerosis. Macrophages possess several cell surface receptors (e.g., the mannose receptor, MR) that may serve as drug delivery cellular portals for nanocarriers (NCs). In this study, the optimal structural configuration for cell uptake of mannosylated poly(ethylene glycol)-conjugate type NCs was determined. A series NCs was synthesized to systematically evaluate the effects of the number of mannose units (Man), the PEG carrier size and the mPEG spacer length between adjacent mannose units on NC uptake into MR-expressing J774.E murine macrophage-like cells. Among NCs with 0, 1, 2 or 4 units of mannose, the uptake of (Man)2-NC was the highest, suggesting a trade-off between avidity and NC-MR clustering on the cell surface that sterically hinders endocytosis. This optimal (Man)2-NC configuration was built into subsequent NCs to optimize the other two parameters, PEG carrier size and spacer length. NCs with 0, 5, 12, 20, 30 or 40 kDa linear PEG carriers showed an inverse relationship between PEG size and uptake. The 12 kDa PEG carrier was chosen for investigating the third parameter, the Man-Man distance, since it may represent the best trade off (i.e., tissue penetration vs. systemic clearance) for in vivo macrophage targeting. Three (Man)2-PEG12kDa NCs with different Man-Man distances (39, 56 or 89 Å) were synthesized. The uptake of the NC with the 56 Å distance between mannoses was four- and two-fold higher than NCs with 39 Å and 89 Å distances, respectively. Confocal microscopy confirmed that the optimized (Man)2-PEG12kDa NC with the 56 Å Man-Man distance was internalized via endocytosis consistent with temperature-dependent active uptake. In conclusion, the optimal NC structural parameters for targeting the MR on macrophage-like J774.E cells are (i) a small PEG polymer carrier, (ii) two mannose units per NC and (iii) a 56 Å distance between

  16. Rejuvenating cellular respiration for optimizing respiratory function: targeting mitochondria.

    PubMed

    Agrawal, Anurag; Mabalirajan, Ulaganathan

    2016-01-15

    Altered bioenergetics with increased mitochondrial reactive oxygen species production and degradation of epithelial function are key aspects of pathogenesis in asthma and chronic obstructive pulmonary disease (COPD). This motif is not unique to obstructive airway disease, reported in related airway diseases such as bronchopulmonary dysplasia and parenchymal diseases such as pulmonary fibrosis. Similarly, mitochondrial dysfunction in vascular endothelium or skeletal muscles contributes to the development of pulmonary hypertension and systemic manifestations of lung disease. In experimental models of COPD or asthma, the use of mitochondria-targeted antioxidants, such as MitoQ, has substantially improved mitochondrial health and restored respiratory function. Modulation of noncoding RNA or protein regulators of mitochondrial biogenesis, dynamics, or degradation has been found to be effective in models of fibrosis, emphysema, asthma, and pulmonary hypertension. Transfer of healthy mitochondria to epithelial cells has been associated with remarkable therapeutic efficacy in models of acute lung injury and asthma. Together, these form a 3R model--repair, reprogramming, and replacement--for mitochondria-targeted therapies in lung disease. This review highlights the key role of mitochondrial function in lung health and disease, with a focus on asthma and COPD, and provides an overview of mitochondria-targeted strategies for rejuvenating cellular respiration and optimizing respiratory function in lung diseases. PMID:26566906

  17. Identifying optimal targets of network attack by belief propagation.

    PubMed

    Mugisha, Salomon; Zhou, Hai-Jun

    2016-07-01

    For a network formed by nodes and undirected links between pairs of nodes, the network optimal attack problem aims at deleting a minimum number of target nodes to break the network down into many small components. This problem is intrinsically related to the feedback vertex set problem that was successfully tackled by spin-glass theory and an associated belief propagation-guided decimation (BPD) algorithm [Zhou, Eur. Phys. J. B 86, 455 (2013)EPJBFY1434-602810.1140/epjb/e2013-40690-1]. In the present work we apply the BPD algorithm (which has approximately linear time complexity) to the network optimal attack problem and demonstrate that it has much better performance than a recently proposed collective information algorithm [Morone and Makse, Nature 524, 65 (2015)NATUAS0028-083610.1038/nature14604] for different types of random networks and real-world network instances. The BPD-guided attack scheme often induces an abrupt collapse of the whole network, which may make it very difficult to defend. PMID:27575146

  18. Identifying optimal targets of network attack by belief propagation

    NASA Astrophysics Data System (ADS)

    Mugisha, Salomon; Zhou, Hai-Jun

    2016-07-01

    For a network formed by nodes and undirected links between pairs of nodes, the network optimal attack problem aims at deleting a minimum number of target nodes to break the network down into many small components. This problem is intrinsically related to the feedback vertex set problem that was successfully tackled by spin-glass theory and an associated belief propagation-guided decimation (BPD) algorithm [Zhou, Eur. Phys. J. B 86, 455 (2013), 10.1140/epjb/e2013-40690-1]. In the present work we apply the BPD algorithm (which has approximately linear time complexity) to the network optimal attack problem and demonstrate that it has much better performance than a recently proposed collective information algorithm [Morone and Makse, Nature 524, 65 (2015), 10.1038/nature14604] for different types of random networks and real-world network instances. The BPD-guided attack scheme often induces an abrupt collapse of the whole network, which may make it very difficult to defend.

  19. A numerically optimized active shield for improved TMS targeting

    PubMed Central

    Hernandez-Garcia, Luis; Hall, Timothy; Gomez, Luis; Michielssen, Eric

    2010-01-01

    Transcranial magnetic stimulation (TMS) devices suffer of poor targeting and penetration depth. A new approach to designing TMS coils is introduced in order to improve the focus of the stimulation region through the use of actively shielded probes. Iterative optimization techniques were used to design different active shielding coils for TMS probes. The new approach aims to increase the amount of energy deposited in a thin cylindrical region below the probe relative to the energy deposited elsewhere in the region (“sharpness”), while simultaneously increase the induced electric field deep in the target region relative to the surface (“penetration”). After convergence, the resulting designs showed that there is a clear tradeoff between sharpness and penetration that can be controlled by the choice of a tuning parameter. The resulting designs were tested on a realistic human head conductivity model, taking the contribution from surface charges into account. The design of choice reduced penetration depths by 16.7%. The activated surface area was reduced by 24.1 % and the volume of the activation was reduced from 42.6% by the shield. Restoring the lost penetration could be achieved by increasing the total power to the coil by 16.3%, but in that case, the stimulated volume reduction was only 13.1% and there was a slight increase in the stimulated surface area (2.9 %) PMID:20965451

  20. Optimized Planning Target Volume for Intact Cervical Cancer

    SciTech Connect

    Khan, Alvin; Jensen, Lindsay G.; Sun Shuai; Song, William Y.; Yashar, Catheryn M.; Mundt, Arno J.; Zhang Fuquan; Jiang, Steve B.; Mell, Loren K.

    2012-08-01

    Purpose: To model interfraction clinical target volume (CTV) variation in patients with intact cervical cancer and design a planning target volume (PTV) that minimizes normal tissue dose while maximizing CTV coverage. Methods and Materials: We analyzed 50 patients undergoing external-beam radiotherapy for intact cervical cancer using daily online cone-beam computed tomography (CBCT). The CBCTs (n = 972) for each patient were rigidly registered to the planning CT. The CTV was delineated on the planning CT (CTV{sub 0}) and the set of CBCTs ({l_brace}CTV{sub 1}-CTV{sub 25}{r_brace}). Manual (n = 98) and automated (n = 668) landmarks were placed over the surface of CTV{sub 0} with reference to defined anatomic structures. Normal vectors were extended from each landmark, and the minimum length required for a given probability of encompassing CTV{sub 1}-CTV{sub 25} was computed. The resulting expansions were used to generate an optimized PTV. Results: The mean (SD; range) normal vector length to ensure 95% coverage was 4.3 mm (2.7 mm; 1-16 mm). The uniform expansion required to ensure 95% probability of CTV coverage was 13 mm. An anisotropic margin of 20 mm anteriorly and posteriorly and 10 mm superiorly, inferiorly, and laterally also would have ensured a 95% probability of CTV coverage. The volume of the 95% optimized PTV (1470 cm{sup 3}) was significantly lower than both the anisotropic PTV (2220 cm{sup 3}) and the uniformly expanded PTV (2110 cm{sup 3}) (p < 0.001). For a 95% probability of CTV coverage, normal lengths of 1-3 mm were found along the superior and lateral regions of CTV{sub 0}, 5-10 mm along the interfaces of CTV{sub 0} with the bladder and rectum, and 10-14 mm along the anterior surface of CTV{sub 0} at the level of the uterus. Conclusion: Optimizing PTV definition according to surface landmarking resulted in a high probability of CTV coverage with reduced PTV volumes. Our results provide data justifying planning margins to use in practice and

  1. Enhancing potency of siRNA targeting fusion genes by optimization outside of target sequence.

    PubMed

    Gavrilov, Kseniya; Seo, Young-Eun; Tietjen, Gregory T; Cui, Jiajia; Cheng, Christopher J; Saltzman, W Mark

    2015-12-01

    Canonical siRNA design algorithms have become remarkably effective at predicting favorable binding regions within a target mRNA, but in some cases (e.g., a fusion junction site) region choice is restricted. In these instances, alternative approaches are necessary to obtain a highly potent silencing molecule. Here we focus on strategies for rational optimization of two siRNAs that target the junction sites of fusion oncogenes BCR-ABL and TMPRSS2-ERG. We demonstrate that modifying the termini of these siRNAs with a terminal G-U wobble pair or a carefully selected pair of terminal asymmetry-enhancing mismatches can result in an increase in potency at low doses. Importantly, we observed that improvements in silencing at the mRNA level do not necessarily translate to reductions in protein level and/or cell death. Decline in protein level is also heavily influenced by targeted protein half-life, and delivery vehicle toxicity can confound measures of cell death due to silencing. Therefore, for BCR-ABL, which has a long protein half-life that is difficult to overcome using siRNA, we also developed a nontoxic transfection vector: poly(lactic-coglycolic acid) nanoparticles that release siRNA over many days. We show that this system can achieve effective killing of leukemic cells. These findings provide insights into the implications of siRNA sequence for potency and suggest strategies for the design of more effective therapeutic siRNA molecules. Furthermore, this work points to the importance of integrating studies of siRNA design and delivery, while heeding and addressing potential limitations such as restricted targetable mRNA regions, long protein half-lives, and nonspecific toxicities. PMID:26627251

  2. Enhancing potency of siRNA targeting fusion genes by optimization outside of target sequence

    PubMed Central

    Gavrilov, Kseniya; Seo, Young-Eun; Tietjen, Gregory T.; Cui, Jiajia; Cheng, Christopher J.; Saltzman, W. Mark

    2015-01-01

    Canonical siRNA design algorithms have become remarkably effective at predicting favorable binding regions within a target mRNA, but in some cases (e.g., a fusion junction site) region choice is restricted. In these instances, alternative approaches are necessary to obtain a highly potent silencing molecule. Here we focus on strategies for rational optimization of two siRNAs that target the junction sites of fusion oncogenes BCR-ABL and TMPRSS2-ERG. We demonstrate that modifying the termini of these siRNAs with a terminal G-U wobble pair or a carefully selected pair of terminal asymmetry-enhancing mismatches can result in an increase in potency at low doses. Importantly, we observed that improvements in silencing at the mRNA level do not necessarily translate to reductions in protein level and/or cell death. Decline in protein level is also heavily influenced by targeted protein half-life, and delivery vehicle toxicity can confound measures of cell death due to silencing. Therefore, for BCR-ABL, which has a long protein half-life that is difficult to overcome using siRNA, we also developed a nontoxic transfection vector: poly(lactic-coglycolic acid) nanoparticles that release siRNA over many days. We show that this system can achieve effective killing of leukemic cells. These findings provide insights into the implications of siRNA sequence for potency and suggest strategies for the design of more effective therapeutic siRNA molecules. Furthermore, this work points to the importance of integrating studies of siRNA design and delivery, while heeding and addressing potential limitations such as restricted targetable mRNA regions, long protein half-lives, and nonspecific toxicities. PMID:26627251

  3. Optimal placement of sensors and actuators for active vibration reduction of a flexible structure using a genetic algorithm based on modified Hinfinity

    NASA Astrophysics Data System (ADS)

    Hale, J. M.; Daraji, A. H.

    2012-08-01

    This paper is concerned with active vibration reduction of a square isotropic plate, mounted rigidly along one edge to form a cantilever. Optimal placement of ten piezoelectric sensor/actuator pairs is investigated using a genetic algorithm to suppress the first six modes of vibration. A new objective function is developed based on modified Hinfinity to locate the sensor/actuator pairs. The plate, with piezoelectric sensor/actuator pairs bonded to its surfaces, is modelled using the finite element method and Hamilton's principle based on first order shear deformation theory including bending, membrane, and shear deformation effects. The effects of piezoelectric mass, stiffness and electromechanical coupling are taken into account. The first six natural frequencies are validated by comparison with the finite element ANSYS package using two dimensional SHELL63 and three dimensional SOLID45 elements and also experimentally. Vibration reduction for the cantilever plate with piezoelectric patches bonded in the optimal location was investigated to attenuate the first six modes of vibration using a linear optimal control scheme. The new fitness function has reduced the computational cost and given greater vibration reduction than other previously published results.

  4. Layout optimization with assist features placement by model based rule tables for 2x node random contact

    NASA Astrophysics Data System (ADS)

    Jun, Jinhyuck; Park, Minwoo; Park, Chanha; Yang, Hyunjo; Yim, Donggyu; Do, Munhoe; Lee, Dongchan; Kim, Taehoon; Choi, Junghoe; Luk-Pat, Gerard; Miloslavsky, Alex

    2015-03-01

    As the industry pushes to ever more complex illumination schemes to increase resolution for next generation memory and logic circuits, sub-resolution assist feature (SRAF) placement requirements become increasingly severe. Therefore device manufacturers are evaluating improvements in SRAF placement algorithms which do not sacrifice main feature (MF) patterning capability. There are known-well several methods to generate SRAF such as Rule based Assist Features (RBAF), Model Based Assist Features (MBAF) and Hybrid Assisted Features combining features of the different algorithms using both RBAF and MBAF. Rule Based Assist Features (RBAF) continue to be deployed, even with the availability of Model Based Assist Features (MBAF) and Inverse Lithography Technology (ILT). Certainly for the 3x nm node, and even at the 2x nm nodes and lower, RBAF is used because it demands less run time and provides better consistency. Since RBAF is needed now and in the future, what is also needed is a faster method to create the AF rule tables. The current method typically involves making masks and printing wafers that contain several experiments, varying the main feature configurations, AF configurations, dose conditions, and defocus conditions - this is a time consuming and expensive process. In addition, as the technology node shrinks, wafer process changes and source shape redesigns occur more frequently, escalating the cost of rule table creation. Furthermore, as the demand on process margin escalates, there is a greater need for multiple rule tables: each tailored to a specific set of main-feature configurations. Model Assisted Rule Tables(MART) creates a set of test patterns, and evaluates the simulated CD at nominal conditions, defocused conditions and off-dose conditions. It also uses lithographic simulation to evaluate the likelihood of AF printing. It then analyzes the simulation data to automatically create AF rule tables. It means that analysis results display the cost of

  5. Optimizing foster family placement for infants and toddlers: A randomized controlled trial on the effect of the foster family intervention.

    PubMed

    Van Andel, Hans; Post, Wendy; Jansen, Lucres; Van der Gaag, Rutger Jan; Knorth, Erik; Grietens, Hans

    2016-01-01

    The relationship between foster children and their foster carers comes with many risks and may be very stressful both for parents and children. We developed an intervention (foster family intervention [FFI]) to tackle these risks. The intervention focuses on foster children below the age of 5 years. The objective was to investigate the effects of FFI on the interactions between foster parents and foster children. A randomized control trial was carried out with a sample of 123 preschool aged children (mean age 18.8 months; 51% boys) and their foster carers. A pretest was carried out 6 to 8 weeks after placement and a posttest one half year later. Interactions were videotaped and coded using the Emotional Availability Scales (EAS). Foster carers were asked to fill in the Dutch version of the Parenting Stress Index. Morning and evening samples of children's salivary cortisol were taken. In the posttest, significantly positive effects were found on the following EAS subscales: Sensitivity, Structuring, Nonintrusiveness, and Responsiveness. We found no significant differences on stress levels of foster carers and children (Nijmeegse Ouderlijke Stress Index domains and salivary cortisol). This study shows that the FFI has a significant positive effect on parenting skills as measured with EAS and on Responsiveness of the foster child. Findings are discussed in terms of impact and significance relating to methodology and design of the study and to clinical relevance. (PsycINFO Database Record PMID:27196390

  6. Optimization Studies for ISOL Type High-Powered Targets

    SciTech Connect

    Remec, Igor; Ronningen, Reginald Martin

    2013-09-24

    The research studied one-step and two-step Isotope Separation on Line (ISOL) targets for future radioactive beam facilities with high driver-beam power through advanced computer simulations. As a target material uranium carbide in the form of foils was used because of increasing demand for actinide targets in rare-isotope beam facilities and because such material was under development in ISAC at TRIUMF when this project started. Simulations of effusion were performed for one-step and two step targets and the effects of target dimensions and foil matrix were studied. Diffusion simulations were limited by availability of diffusion parameters for UCx material at reduced density; however, the viability of the combined diffusion?effusion simulation methodology was demonstrated and could be used to extract physical parameters such as diffusion coefficients and effusion delay times from experimental isotope release curves. Dissipation of the heat from the isotope-producing targets is the limiting factor for high-power beam operation both for the direct and two-step targets. Detailed target models were used to simulate proton beam interactions with the targets to obtain the fission rates and power deposition distributions, which were then applied in the heat transfer calculations to study the performance of the targets. Results indicate that a direct target, with specification matching ISAC TRIUMF target, could operate in 500-MeV proton beam at beam powers up to ~40 kW, producing ~8 1013 fission/s with maximum temperature in UCx below 2200 C. Targets with larger radius allow higher beam powers and fission rates. For the target radius in the range 9-mm to 30-mm the achievable fission rate increases almost linearly with target radius, however, the effusion delay time also increases linearly with target radius.

  7. Optimal random search for a single hidden target.

    PubMed

    Snider, Joseph

    2011-01-01

    A single target is hidden at a location chosen from a predetermined probability distribution. Then, a searcher must find a second probability distribution from which random search points are sampled such that the target is found in the minimum number of trials. Here it will be shown that if the searcher must get very close to the target to find it, then the best search distribution is proportional to the square root of the target distribution regardless of dimension. For a Gaussian target distribution, the optimum search distribution is approximately a Gaussian with a standard deviation that varies inversely with how close the searcher must be to the target to find it. For a network where the searcher randomly samples nodes and looks for the fixed target along edges, the optimum is either to sample a node with probability proportional to the square root of the out-degree plus 1 or not to do so at all. PMID:21405659

  8. Analysis of the optimal laminated target made up of discrete set of materials

    NASA Technical Reports Server (NTRS)

    Aptukov, Valery N.; Belousov, Valentin L.

    1991-01-01

    A new class of problems was analyzed to estimate an optimal structure of laminated targets fabricated from the specified set of homogeneous materials. An approximate description of the perforation process is based on the model of radial hole extension. The problem is solved by using the needle-type variation technique. The desired optimization conditions and quantitative/qualitative estimations of optimal targets were obtained and are discussed using specific examples.

  9. Method and apparatus for optimized sampling of volatilizable target substances

    DOEpatents

    Lindgren, Eric R.; Phelan, James M.

    2002-01-01

    An apparatus for capturing, from gases such as soil gas, target analytes. Target analytes may include emanations from explosive materials or from residues of explosive materials. The apparatus employs principles of sorption common to solid phase microextraction, and is best used in conjunction with analysis means such as a gas chromatograph. To sorb target analytes, the apparatus functions using various sorptive structures to capture target analyte. Depending upon the embodiment, those structures may include 1) a conventional solid-phase microextraction (SPME) fiber, 2) a SPME fiber suspended in a capillary tube (with means provided for moving gases through the capillary tube so that the gases come into close proximity to the suspended fiber), and 3) a capillary tube including an interior surface on which sorptive material (similar to that on the surface of a SPME fiber) is supported (along with means for moving gases through the capillary tube so that the gases come into close proximity to the sorptive material). In one disclosed embodiment, at least one such sorptive structure is associated with an enclosure including an opening in communication with the surface of a soil region potentially contaminated with buried explosive material such as unexploded ordnance. Emanations from explosive materials can pass into and accumulate in the enclosure where they are sorbed by the sorptive structures. Also disclosed is the use of heating means such as microwave horns to drive target analytes into the soil gas from solid and liquid phase components of the soil.

  10. Method and apparatus for optimized sampling of volatilizable target substances

    DOEpatents

    Lindgren, Eric R.; Phelan, James M.

    2004-10-12

    An apparatus for capturing, from gases such as soil gas, target analytes. Target analytes may include emanations from explosive materials or from residues of explosive materials. The apparatus employs principles of sorption common to solid phase microextraction, and is best used in conjunction with analysis means such as a gas chromatograph. To sorb target analytes, the apparatus functions using various sorptive structures to capture target analyte. Depending upon the embodiment, those structures may include a capillary tube including an interior surface on which sorptive material (similar to that on the surface of a SPME fiber) is supported (along with means for moving gases through the capillary tube so that the gases come into close proximity to the sorptive material). In one disclosed embodiment, at least one such sorptive structure is associated with an enclosure including an opening in communication with the surface of a soil region potentially contaminated with buried explosive material such as unexploded ordnance. Emanations from explosive materials can pass into and accumulate in the enclosure where they are sorbed by the sorptive structures. Also disclosed is the use of heating means such as microwave horns to drive target analytes into the soil gas from solid and liquid phase components of the soil.

  11. Optimal placement of unified power flow controllers to improve dynamic voltage stability using power system variable based voltage stability indices.

    PubMed

    Albatsh, Fadi M; Ahmad, Shameem; Mekhilef, Saad; Mokhlis, Hazlie; Hassan, M A

    2015-01-01

    This study examines a new approach to selecting the locations of unified power flow controllers (UPFCs) in power system networks based on a dynamic analysis of voltage stability. Power system voltage stability indices (VSIs) including the line stability index (LQP), the voltage collapse proximity indicator (VCPI), and the line stability index (Lmn) are employed to identify the most suitable locations in the system for UPFCs. In this study, the locations of the UPFCs are identified by dynamically varying the loads across all of the load buses to represent actual power system conditions. Simulations were conducted in a power system computer-aided design (PSCAD) software using the IEEE 14-bus and 39- bus benchmark power system models. The simulation results demonstrate the effectiveness of the proposed method. When the UPFCs are placed in the locations obtained with the new approach, the voltage stability improves. A comparison of the steady-state VSIs resulting from the UPFCs placed in the locations obtained with the new approach and with particle swarm optimization (PSO) and differential evolution (DE), which are static methods, is presented. In all cases, the UPFC locations given by the proposed approach result in better voltage stability than those obtained with the other approaches. PMID:25874560

  12. Optimal Placement of Unified Power Flow Controllers to Improve Dynamic Voltage Stability Using Power System Variable Based Voltage Stability Indices

    PubMed Central

    Albatsh, Fadi M.; Ahmad, Shameem; Mekhilef, Saad; Mokhlis, Hazlie; Hassan, M. A.

    2015-01-01

    This study examines a new approach to selecting the locations of unified power flow controllers (UPFCs) in power system networks based on a dynamic analysis of voltage stability. Power system voltage stability indices (VSIs) including the line stability index (LQP), the voltage collapse proximity indicator (VCPI), and the line stability index (Lmn) are employed to identify the most suitable locations in the system for UPFCs. In this study, the locations of the UPFCs are identified by dynamically varying the loads across all of the load buses to represent actual power system conditions. Simulations were conducted in a power system computer-aided design (PSCAD) software using the IEEE 14-bus and 39- bus benchmark power system models. The simulation results demonstrate the effectiveness of the proposed method. When the UPFCs are placed in the locations obtained with the new approach, the voltage stability improves. A comparison of the steady-state VSIs resulting from the UPFCs placed in the locations obtained with the new approach and with particle swarm optimization (PSO) and differential evolution (DE), which are static methods, is presented. In all cases, the UPFC locations given by the proposed approach result in better voltage stability than those obtained with the other approaches. PMID:25874560

  13. SIMPLIMAX: Oblique Rotation to an Optimal Target with Simple Structure.

    ERIC Educational Resources Information Center

    Kiers, Henk A. L.

    1994-01-01

    A class of oblique rotation procedures is proposed to rotate a pattern matrix so that it optimally resembles a matrix that has an exact simple pattern. It is demonstrated that the method can recover relatively complex simple structures where other simple structure rotation techniques fail. (SLD)

  14. Optimizing laser-driven proton acceleration from overdense targets

    PubMed Central

    Stockem Novo, A.; Kaluza, M. C.; Fonseca, R. A.; Silva, L. O.

    2016-01-01

    We demonstrate how to tune the main ion acceleration mechanism in laser-plasma interactions to collisionless shock acceleration, thus achieving control over the final ion beam properties (e. g. maximum energy, divergence, number of accelerated ions). We investigate this technique with three-dimensional particle-in-cell simulations and illustrate a possible experimental realisation. The setup consists of an isolated solid density target, which is preheated by a first laser pulse to initiate target expansion, and a second one to trigger acceleration. The timing between the two laser pulses allows to access all ion acceleration regimes, ranging from target normal sheath acceleration, to hole boring and collisionless shock acceleration. We further demonstrate that the most energetic ions are produced by collisionless shock acceleration, if the target density is near-critical, ne ≈ 0.5 ncr. A scaling of the laser power shows that 100 MeV protons may be achieved in the PW range. PMID:27435449

  15. Optimizing laser-driven proton acceleration from overdense targets.

    PubMed

    Stockem Novo, A; Kaluza, M C; Fonseca, R A; Silva, L O

    2016-01-01

    We demonstrate how to tune the main ion acceleration mechanism in laser-plasma interactions to collisionless shock acceleration, thus achieving control over the final ion beam properties (e. g. maximum energy, divergence, number of accelerated ions). We investigate this technique with three-dimensional particle-in-cell simulations and illustrate a possible experimental realisation. The setup consists of an isolated solid density target, which is preheated by a first laser pulse to initiate target expansion, and a second one to trigger acceleration. The timing between the two laser pulses allows to access all ion acceleration regimes, ranging from target normal sheath acceleration, to hole boring and collisionless shock acceleration. We further demonstrate that the most energetic ions are produced by collisionless shock acceleration, if the target density is near-critical, ne ≈ 0.5 ncr. A scaling of the laser power shows that 100 MeV protons may be achieved in the PW range. PMID:27435449

  16. Optimizing laser-driven proton acceleration from overdense targets

    NASA Astrophysics Data System (ADS)

    Stockem Novo, A.; Kaluza, M. C.; Fonseca, R. A.; Silva, L. O.

    2016-07-01

    We demonstrate how to tune the main ion acceleration mechanism in laser-plasma interactions to collisionless shock acceleration, thus achieving control over the final ion beam properties (e. g. maximum energy, divergence, number of accelerated ions). We investigate this technique with three-dimensional particle-in-cell simulations and illustrate a possible experimental realisation. The setup consists of an isolated solid density target, which is preheated by a first laser pulse to initiate target expansion, and a second one to trigger acceleration. The timing between the two laser pulses allows to access all ion acceleration regimes, ranging from target normal sheath acceleration, to hole boring and collisionless shock acceleration. We further demonstrate that the most energetic ions are produced by collisionless shock acceleration, if the target density is near-critical, ne ≈ 0.5 ncr. A scaling of the laser power shows that 100 MeV protons may be achieved in the PW range.

  17. Efficient optimal design of smooth optical freeform surfaces using ray targeting

    NASA Astrophysics Data System (ADS)

    Wu, Rengmao; Wang, Huihui; Liu, Peng; Zhang, Yaqin; Zheng, Zhenrong; Li, Haifeng; Liu, Xu

    2013-07-01

    An optimization design method is proposed for generating smooth freeform reflective and refractive surfaces. In this method, two optimization steps are employed for ray targeting. The first step aims to ensure the shape of the target illumination, and the second step is employed to further improve the irradiance uniformity. These two steps can provide significant savings of time because the time consuming Monte Carlo raytracing is not used during the optimization process. Both smooth freeform reflective surfaces and smooth freeform refractive surfaces can be designed, and the target illumination could be achieved just by controlling the positions of several hundred predefined rays on the target plane with these two steps. The simulation results and the experimental tests show that this optimization design method is robust and efficient.

  18. Pancreatic cancer: optimizing treatment options, new, and emerging targeted therapies

    PubMed Central

    Chiorean, Elena Gabriela; Coveler, Andrew L

    2015-01-01

    Pancreatic cancer is the fourth leading cause of cancer death in the US and is expected to become the second leading cause of cancer-related deaths in the next decade. Despite 5-fluorouracil/leucovorin with irinotecan and oxaliplatin (FOLFIRINOX) and gemcitabine/nab-paclitaxel significantly improving outcomes for metastatic cancer, refractory disease still poses significant challenges. Difficulties with early detection and the inherent chemo- and radio-resistant nature of this malignancy led to attempts to define the sequential biology of pancreatic cancer in order to improve survival outcomes. Pancreatic adenocarcinoma is characterized by several germline or acquired genetic mutations, the most common being KRAS (90%), CDK2NA (90%), TP53 (75%–90%), DPC4/SMAD4 (50%). In addition, the tumor microenvironment, chemoresistant cancer stem cells, and the desmoplastic stroma have been the target of some promising clinical investigations. Among the core pathways reproducibly shown to lead the development and progression of this disease, DNA repair, apoptosis, G1/S cell cycle transition, KRAS, Wnt, Notch, Hedgehog, TGF-beta, and other cell invasion pathways, have been the target of “precision therapeutics”. No single molecularly targeted therapeutic though has been uniformly successful, probably due to the tumor heterogeneity, but biomarker research is evolving and it hopes to select more patients likely to benefit. Recent reports note activity with immunotherapies such as CD40 agonists, CCR2 inhibitors, cancer vaccines, and novel combinations against the immunosuppressive tumor milieu are ongoing. While many obstacles still exist, clearly we are making progress in deciphering the heterogeneity within pancreatic cancers. Integrating conventional and immunological targeting will be the key to effective treatment of this deadly disease. PMID:26185420

  19. Differential Evolution Optimization for Targeting Spacecraft Maneuver Plans

    NASA Technical Reports Server (NTRS)

    Mattern, Daniel

    2016-01-01

    Previous analysis identified specific orbital parameters as being safer for conjunction avoidance for the TDRS fleet. With TDRS-9 being considered an at-risk spacecraft, a potential conjunction concern was raised should TDRS-9 fail while at a longitude of 12W. This document summarizes the analysis performed to identify if these specific orbital parameters could be targeted using the remaining drift-termination maneuvers for the relocation of TDRS-9 from 41W longitude to 12W longitude.

  20. "Smart" source, mask, and target co-optimization to improve design related lithographically weak spots

    NASA Astrophysics Data System (ADS)

    Chung, No-Young; Kang, Pil-Soo; Bang, Na-Rae; Kim, Jong-Du; Lee, Suk-Ju; Choi, Byung-Il; Choi, Bong-Ryoul; Park, Sung-Woon; Baik, Ki-Ho; Hsu, Stephen; Howell, Rafael; Liu, Xiaofeng; Gronlund, Keith

    2014-03-01

    As patterns shrink to physical limits, advanced Resolution Enhancement Technologies (RET) encounter increasing challenges to ensure a manufacturable Process Window (PW). Moreover, due to the wide variety of pattern constructs for logic device layers, lithographically weak patterns (spots) become a difficult obstacle despite Source and Mask co- Optimization (SMO) and advanced OPC being applied. In order to overcome these design related lithographically weak spots, designers need lithography based simulator feedback to develop robust design rules and RET/OPC engineers must co-optimize the overall imaging capability and corresponding design lithography target. To meet these needs, a new optimization method called SmartDRO (Design Rule Optimization) has been developed. SmartDRO utilizes SMO's Continuous Transmission Mask (CTM) methodology and optimization algorithm including design target variables in the cost function. This optimizer finds the recommended lithography based target using the SMO engine. In this paper, we introduce a new optimization flow incorporating this SmartDRO capability to optimize the target layout within the cell to improve the manufacturable process window. With this new methodology, the most advanced L/S patterns such as metal (k1 = 0.28) and the most challenging contact patterns such as via (k1 = 0.33) are enabled and meet process window requirements.

  1. Performance consequences of parity placement in disk arrays

    NASA Technical Reports Server (NTRS)

    Lee, Edward K.; Katz, Randy H.

    1991-01-01

    The performance of a variety of parity placement schemes are defined and investigated to demonstrate that, at relatively large request sizes of hundreds of kilobytes, the choice of parity placement significantly affects performance (20 to 30 percent for the disk array configurations that are common today). It is shown that the left-symmetric, extended-left-symmetric and flat-left-symmetric are the best RAID level 5 parity placements. The placement with the highest read performance, flat-left-symmetric, has the lowest write performance, while the placement with the lowest read performance, left-symmetric, has the highest write performance. Suggestions for optimizing parity placements are included.

  2. An intrinsically safe facility for forefront research and training on nuclear technologies — Target profile optimization

    NASA Astrophysics Data System (ADS)

    Ciotti, Marco

    2014-04-01

    A simple 1D algorithm for a spallation target profile optimization is presented. The profile efficacy is tested considering different real particle beams profiles impinging on the target. The results are commented in terms of power non-homogeneity for unit length for different beam/profile choices, showing a non-trivial parameters selection. In details, target shaping optimization is possible knowing the beam parameters with a large benefit for surface power homogeneity, but results of the simulations show that a small increase of the beam dimension, or a beam shift with respect to the assumed one, could rapidly erase the advantages.

  3. Levy flights do not always optimize random blind search for sparse targets.

    PubMed

    Palyulin, Vladimir V; Chechkin, Aleksei V; Metzler, Ralf

    2014-02-25

    It is generally believed that random search processes based on scale-free, Lévy stable jump length distributions (Lévy flights) optimize the search for sparse targets. Here we show that this popular search advantage is less universal than commonly assumed. We study the efficiency of a minimalist search model based on Lévy flights in the absence and presence of an external drift (underwater current, atmospheric wind, a preference of the walker owing to prior experience, or a general bias in an abstract search space) based on two different optimization criteria with respect to minimal search time and search reliability (cumulative arrival probability). Although Lévy flights turn out to be efficient search processes when the target is far from the starting point, or when relative to the starting point the target is upstream, we show that for close targets and for downstream target positioning regular Brownian motion turns out to be the advantageous search strategy. Contrary to claims that Lévy flights with a critical exponent α = 1 are optimal for the search of sparse targets in different settings, based on our optimization parameters the optimal α may range in the entire interval (1, 2) and especially include Brownian motion as the overall most efficient search strategy. PMID:24516153

  4. Lévy flights do not always optimize random blind search for sparse targets

    PubMed Central

    Palyulin, Vladimir V.; Chechkin, Aleksei V.; Metzler, Ralf

    2014-01-01

    It is generally believed that random search processes based on scale-free, Lévy stable jump length distributions (Lévy flights) optimize the search for sparse targets. Here we show that this popular search advantage is less universal than commonly assumed. We study the efficiency of a minimalist search model based on Lévy flights in the absence and presence of an external drift (underwater current, atmospheric wind, a preference of the walker owing to prior experience, or a general bias in an abstract search space) based on two different optimization criteria with respect to minimal search time and search reliability (cumulative arrival probability). Although Lévy flights turn out to be efficient search processes when the target is far from the starting point, or when relative to the starting point the target is upstream, we show that for close targets and for downstream target positioning regular Brownian motion turns out to be the advantageous search strategy. Contrary to claims that Lévy flights with a critical exponent α = 1 are optimal for the search of sparse targets in different settings, based on our optimization parameters the optimal α may range in the entire interval (1, 2) and especially include Brownian motion as the overall most efficient search strategy. PMID:24516153

  5. Nonalcoholic steatohepatitis: emerging targeted therapies to optimize treatment options

    PubMed Central

    Milic, Sandra; Mikolasevic, Ivana; Krznaric-Zrnic, Irena; Stanic, Marija; Poropat, Goran; Stimac, Davor; Vlahovic-Palcevski, Vera; Orlic, Lidija

    2015-01-01

    Diet and lifestyle changes have led to worldwide increases in the prevalences of obesity and metabolic syndrome, resulting in substantially greater incidence of nonalcoholic fatty liver disease (NAFLD). NAFLD is considered a hepatic manifestation of metabolic syndrome and is related to diabetes, insulin resistance, central obesity, hyperlipidemia, and hypertension. Nonalcoholic steatohepatitis (NASH) is an entity that describes liver inflammation due to NAFLD. Growing evidence suggests that NAFLD is a multisystem disease with a clinical burden that is not only confined to liver-related morbidity and mortality, but that also affects several extra-hepatic organs and regulatory pathways. Thus, NAFLD is considered an important public health issue, but there is currently no effective therapy for all NAFLD patients in the general population. Studies seeking optimal therapy for NAFLD and NASH have not yet led to development of a universal protocol for treating this growing problem. Several pharmacological agents have been studied in an effort to improve insulin resistance and the proinflammatory mediators that may be responsible for NASH progression. Cardiovascular risk factors are highly prevalent among NASH patients, and the backbone of treatment regimens for these patients still comprises general lifestyle interventions, including dietary changes and increased physical activity. Vitamin E and thiazolidinedione derivatives are currently the most evidence-based therapeutic options, but only limited clinical evidence is available regarding their long-term efficacy and safety. Vitamin D and renin–angiotensin–aldosterone system blockers are promising drugs that are currently being intensively investigated for use in NAFLD/NASH patients. PMID:26316717

  6. Echolocating bats use future-target information for optimal foraging.

    PubMed

    Fujioka, Emyo; Aihara, Ikkyu; Sumiya, Miwa; Aihara, Kazuyuki; Hiryu, Shizuko

    2016-04-26

    When seeing or listening to an object, we aim our attention toward it. While capturing prey, many animal species focus their visual or acoustic attention toward the prey. However, for multiple prey items, the direction and timing of attention for effective foraging remain unknown. In this study, we adopted both experimental and mathematical methodology with microphone-array measurements and mathematical modeling analysis to quantify the attention of echolocating bats that were repeatedly capturing airborne insects in the field. Here we show that bats select rational flight paths to consecutively capture multiple prey items. Microphone-array measurements showed that bats direct their sonar attention not only to the immediate prey but also to the next prey. In addition, we found that a bat's attention in terms of its flight also aims toward the next prey even when approaching the immediate prey. Numerical simulations revealed a possibility that bats shift their flight attention to control suitable flight paths for consecutive capture. When a bat only aims its flight attention toward its immediate prey, it rarely succeeds in capturing the next prey. These findings indicate that bats gain increased benefit by distributing their attention among multiple targets and planning the future flight path based on additional information of the next prey. These experimental and mathematical studies allowed us to observe the process of decision making by bats during their natural flight dynamics. PMID:27071082

  7. Echolocating bats use future-target information for optimal foraging

    PubMed Central

    Fujioka, Emyo; Aihara, Ikkyu; Sumiya, Miwa; Aihara, Kazuyuki; Hiryu, Shizuko

    2016-01-01

    When seeing or listening to an object, we aim our attention toward it. While capturing prey, many animal species focus their visual or acoustic attention toward the prey. However, for multiple prey items, the direction and timing of attention for effective foraging remain unknown. In this study, we adopted both experimental and mathematical methodology with microphone-array measurements and mathematical modeling analysis to quantify the attention of echolocating bats that were repeatedly capturing airborne insects in the field. Here we show that bats select rational flight paths to consecutively capture multiple prey items. Microphone-array measurements showed that bats direct their sonar attention not only to the immediate prey but also to the next prey. In addition, we found that a bat’s attention in terms of its flight also aims toward the next prey even when approaching the immediate prey. Numerical simulations revealed a possibility that bats shift their flight attention to control suitable flight paths for consecutive capture. When a bat only aims its flight attention toward its immediate prey, it rarely succeeds in capturing the next prey. These findings indicate that bats gain increased benefit by distributing their attention among multiple targets and planning the future flight path based on additional information of the next prey. These experimental and mathematical studies allowed us to observe the process of decision making by bats during their natural flight dynamics. PMID:27071082

  8. Screening and Optimization of Ligand Conjugates for Lysosomal Targeting

    PubMed Central

    Meerovich, Igor; Koshkaryev, Alexander; Thekkedath, Ritesh; Torchilin, Vladimir P.

    2011-01-01

    The use of lysosome-targeted liposomes may significantly improve the delivery of therapeutic enzymes and chaperones into lysosomes for the treatment of lysosomal storage disorders. The aim of this research was to synthesize new potentially lysosomotropic ligands on a base of Neutral Red and rhodamine B and to study their ability to enhance specific lysosomal delivery of surface-modified liposomes loaded with a model compound, fluorescein isothiocyanate-dextran (FD). The delivery of these liposomes and their content to lysosomes in HeLa cells was investigated by confocal immunofluorescent microscopy, subcellular fractionation and flow cytometry. Confocal microscopy demonstrated that liposomes modified with derivatives of rhodamine B provide good rate of co-localization well the specific lysosomal markers. The comparison of fluorescence of FD in lysosomes isolated by subcellular fractionation also showed that the efficiency of lysosomal delivery of liposomal load by liposomes modified with some of synthesized ligands was significantly higher compared with plain liposomes. These results were additionally confirmed by the flow cytometry of the intact cells treated with liposomes loaded with with 5-dodecanoylaminofluorescein di-β-D-galactopyranoside, a specific substrate for the intralysosomal β-galactosidase, using a number of cell lines, including macrophages with induced phenotype of lysosomal enzyme deficiency; two of the synthesized ligands – rhodamine B DSPE-PEG2k-amide and 6-(3-(DSPE-PEG2k)-thioureido) rhodamine B – demonstrated enhanced lysosomal delivery, in some cases, higher than that for commercially available rhodamine B octadecyl ester, with the best results (the enhancement of the lysosomal delivery up to 75% greater in comparison to plain liposomes) shown for the cells with induced lysosomal enzyme deficiency phenotype. Use of liposomes modified with rhodamine B derivatives may be advantageous for the development of drug delivery systems for the

  9. CT-Finder: A Web Service for CRISPR Optimal Target Prediction and Visualization.

    PubMed

    Zhu, Houxiang; Misel, Lauren; Graham, Mitchell; Robinson, Michael L; Liang, Chun

    2016-01-01

    The CRISPR system holds much promise for successful genome engineering, but therapeutic, industrial, and research applications will place high demand on improving the specificity and efficiency of this tool. CT-Finder (http://bioinfolab.miamioh.edu/ct-finder) is a web service to help users design guide RNAs (gRNAs) optimized for specificity. CT-Finder accommodates the original single-gRNA Cas9 system and two specificity-enhancing paired-gRNA systems: Cas9 D10A nickases (Cas9n) and dimeric RNA-guided FokI nucleases (RFNs). Optimal target candidates can be chosen based on the minimization of predicted off-target effects. Graphical visualization of on-target and off-target sites in the genome is provided for target validation. Major model organisms are covered by this web service. PMID:27210050

  10. CT-Finder: A Web Service for CRISPR Optimal Target Prediction and Visualization

    PubMed Central

    Zhu, Houxiang; Misel, Lauren; Graham, Mitchell; Robinson, Michael L.; Liang, Chun

    2016-01-01

    The CRISPR system holds much promise for successful genome engineering, but therapeutic, industrial, and research applications will place high demand on improving the specificity and efficiency of this tool. CT-Finder (http://bioinfolab.miamioh.edu/ct-finder) is a web service to help users design guide RNAs (gRNAs) optimized for specificity. CT-Finder accommodates the original single-gRNA Cas9 system and two specificity-enhancing paired-gRNA systems: Cas9 D10A nickases (Cas9n) and dimeric RNA-guided FokI nucleases (RFNs). Optimal target candidates can be chosen based on the minimization of predicted off-target effects. Graphical visualization of on-target and off-target sites in the genome is provided for target validation. Major model organisms are covered by this web service. PMID:27210050

  11. Patient-specific port placement for laparoscopic surgery using atlas-based registration

    NASA Astrophysics Data System (ADS)

    Enquobahrie, Andinet; Shivaprabhu, Vikas; Aylward, Stephen; Finet, Julien; Cleary, Kevin; Alterovitz, Ron

    2013-03-01

    Laparoscopic surgery is a minimally invasive surgical approach, in which abdominal surgical procedures are performed through trocars via small incisions. Patients benefit by reduced postoperative pain, shortened hospital stays, improved cosmetic results, and faster recovery times. Optimal port placement can improve surgeon dexterity and avoid the need to move the trocars, which would cause unnecessary trauma to the patient. We are building an intuitive open source visualization system to help surgeons identify ports. Our methodology is based on an intuitive port placement visualization module and atlas-based registration algorithm to transfer port locations to individual patients. The methodology follows three steps:1) Use a port placement visualization module to manually place ports in an abdominal organ atlas. This step generates port-augmented abdominal atlas. This is done only once for a given patient population. 2) Register the atlas data with the patient CT data, to transfer the prescribed ports to the individual patient 3) Review and adjust the transferred port locations using the port placement visualization module. Tool maneuverability and target reachability can be tested using the visualization system. Our methodology would decrease the amount of physician input necessary to optimize port placement for each patient case. In a follow up work, we plan to use the transferred ports as starting point for further optimization of the port locations by formulating a cost function that will take into account factors such as tool dexterity and likelihood of collision between instruments.

  12. Multi-Robot, Multi-Target Particle Swarm Optimization Search in Noisy Wireless Environments

    SciTech Connect

    Kurt Derr; Milos Manic

    2009-05-01

    Multiple small robots (swarms) can work together using Particle Swarm Optimization (PSO) to perform tasks that are difficult or impossible for a single robot to accomplish. The problem considered in this paper is exploration of an unknown environment with the goal of finding a target(s) at an unknown location(s) using multiple small mobile robots. This work demonstrates the use of a distributed PSO algorithm with a novel adaptive RSS weighting factor to guide robots for locating target(s) in high risk environments. The approach was developed and analyzed on multiple robot single and multiple target search. The approach was further enhanced by the multi-robot-multi-target search in noisy environments. The experimental results demonstrated how the availability of radio frequency signal can significantly affect robot search time to reach a target.

  13. Optimized multi-electrode stimulation increases focality and intensity at target

    NASA Astrophysics Data System (ADS)

    Dmochowski, Jacek P.; Datta, Abhishek; Bikson, Marom; Su, Yuzhuo; Parra, Lucas C.

    2011-08-01

    Transcranial direct current stimulation (tDCS) provides a non-invasive tool to elicit neuromodulation by delivering current through electrodes placed on the scalp. The present clinical paradigm uses two relatively large electrodes to inject current through the head resulting in electric fields that are broadly distributed over large regions of the brain. In this paper, we present a method that uses multiple small electrodes (i.e. 1.2 cm diameter) and systematically optimize the applied currents to achieve effective and targeted stimulation while ensuring safety of stimulation. We found a fundamental trade-off between achievable intensity (at the target) and focality, and algorithms to optimize both measures are presented. When compared with large pad-electrodes (approximated here by a set of small electrodes covering 25cm2), the proposed approach achieves electric fields which exhibit simultaneously greater focality (80% improvement) and higher target intensity (98% improvement) at cortical targets using the same total current applied. These improvements illustrate the previously unrecognized and non-trivial dependence of the optimal electrode configuration on the desired electric field orientation and the maximum total current (due to safety). Similarly, by exploiting idiosyncratic details of brain anatomy, the optimization approach significantly improves upon prior un-optimized approaches using small electrodes. The analysis also reveals the optimal use of conventional bipolar montages: maximally intense tangential fields are attained with the two electrodes placed at a considerable distance from the target along the direction of the desired field; when radial fields are desired, the maximum-intensity configuration consists of an electrode placed directly over the target with a distant return electrode. To summarize, if a target location and stimulation orientation can be defined by the clinician, then the proposed technique is superior in terms of both focality

  14. Development of an uncertainty technique using Bayesian methods to study the impact of climate change and land use change on solutions obtained by the BMP selection and placement optimization tool

    NASA Astrophysics Data System (ADS)

    Maringanti, C.; Chaubey, I.

    2009-12-01

    A multi-objective genetic algorithm (NSGA-II) in combination with a watershed model (Soil and Water Assessment Tool (SWAT)) is used in an optimization framework for making the Best Management Practices (BMP) selection and placement decisions to reduce the nonpoint source (NPS) pollutants and the net cost for implementation of BMPs. Shuffled complex evolutionary metropolis uncertainty analysis (SCEM-UA) method will be used to quantify the uncertainty of the BMP selection and placement tool. The sources of input uncertainty for the tool include the uncertainties in the estimation of economic costs for the implementation of BMPs, and input SWAT model predictions at field level. The SWAT model predictions are in turn influenced by the model parameters and the input climate forcing such as precipitation and temperature which in turn are affected due to the changing climate, and the changing land use in the watershed. The optimization tool is also influenced by the operational parameters of the genetic algorithm. The SCEM-UA method will be initiated using a uniform distribution for the range of the model parameters and the input sources of uncertainty to estimate the posterior probability distribution of the model response variables. This methodology will be applied to estimate the uncertainty in the BMP selection and placement in Wildcat Creek Watershed located in northcentral Indiana. Nitrogen, phosphorus, sediment, and pesticide are the various NPS pollutants that will be reduced through implementation of BMPs in the watershed. The uncertainty bounds around the Pareto-optimal fronts after the optimization will provide the watershed management groups a clear insight on how the desired water quality goals could be realistically met for the least amount of money that is available for BMP implementation in the watershed.

  15. Navigated marker placement for motion compensation in radiotherapy

    NASA Astrophysics Data System (ADS)

    Winterstein, A.; März, K.; Franz, A. M.; Hafezi, M.; Fard, N.; Sterzing, F.; Mehrabi, A.; Maier-Hein, L.

    2015-03-01

    Radiotherapy is frequently used to treat unoperated or partially resected tumors. Tumor movement, e.g. caused by respiration, is a major challenge in this context. Markers can be implanted around the tumor prior to radiation therapy for accurate tracking of tumor movement. However, accurate placement of these markers while keeping a secure margin around the target and while taking into account critical structures is a difficult task. Computer-assisted needle insertion has been an active field of research in the past decades. However, the challenge of navigated marker placement for motion compensated radiotherapy has not yet been addressed. This work presents a system to support marker implantation for radiotherapy under consideration of safety margins and optimal marker configuration. It is designed to allow placement of markers both percutaneously and during an open liver surgery. To this end, we adapted the previously proposed EchoTrack system which integrates ultrasound (US) imaging and electromagnetic (EM) tracking in a single mobile modality. The potential of our new marker insertion concept was evaluated in a phantom study by inserting sets of three markers around dedicated targets (n=22) simultaneously spacing the markers evenly around the target as well as placing the markers in a defined distance to the target. In all cases the markers were successfully placed in a configuration fulfilling the predefined criteria. This includes a minimum distance of 18.9 ± 2.4 mm between marker and tumor as well as a divergence of 2.1 ± 1.5 mm from the planned marker positions. We conclude that our system has high potential to facilitate the placement of markers in suitable configurations for surgeons without extensive experience in needle punctions as high quality configurations were obtained even by medical non-experts.

  16. Genetic Algorithm Approaches for Actuator Placement

    NASA Technical Reports Server (NTRS)

    Crossley, William A.

    2000-01-01

    This research investigated genetic algorithm approaches for smart actuator placement to provide aircraft maneuverability without requiring hinged flaps or other control surfaces. The effort supported goals of the Multidisciplinary Design Optimization focus efforts in NASA's Aircraft au program. This work helped to properly identify various aspects of the genetic algorithm operators and parameters that allow for placement of discrete control actuators/effectors. An improved problem definition, including better definition of the objective function and constraints, resulted from this research effort. The work conducted for this research used a geometrically simple wing model; however, an increasing number of potential actuator placement locations were incorporated to illustrate the ability of the GA to determine promising actuator placement arrangements. This effort's major result is a useful genetic algorithm-based approach to assist in the discrete actuator/effector placement problem.

  17. Reversible Masking Using Low-Molecular-Weight Neutral Lipids to Achieve Optimal-Targeted Delivery

    PubMed Central

    Templeton, Nancy Smyth; Senzer, Neil

    2012-01-01

    Intravenous injection of therapeutics is required to effectively treat or cure metastatic cancer, certain cardiovascular diseases, and other acquired or inherited diseases. Using this route of delivery allows potential uptake in all disease targets that are accessed by the bloodstream. However, normal tissues and organs also have the potential for uptake of therapeutic agents. Therefore, investigators have used targeted delivery to attempt delivery solely to the target cells; however, use of ligands on the surface of delivery vehicles to target specific cell surface receptors is not sufficient to avoid nonspecific uptake. PEGylation has been used for decades to try to avoid nonspecific uptake but suffers from many problems known as “The PEGylation Dilemma.” We have solved this dilemma by replacing PEGylation with reversible masking using low-molecular-weight neutral lipids in order to achieve optimal-targeted delivery solely to target cells. Our paper will focus on this topic. PMID:22655199

  18. A Placement Advisory Test

    ERIC Educational Resources Information Center

    Hughes, Chris

    2010-01-01

    The primary method of placement at Portland CC (PCC) is the Compass Placement test. For the most part, students are placed correctly, but there are cases when students feel that they have been placed too low. In such cases we use our newly created Placement Advisory Test (PAT) to help us place them appropriately. (Contains 2 figures.)

  19. Job Placement Handbook.

    ERIC Educational Resources Information Center

    Los Angeles Unified School District, CA. Div. of Career and Continuing Education.

    Designed to serve as a guide for job placement personnel, this handbook is written from the point of view of a school or job preparation facility, based on methodology applicable to the placement function in any setting. Factors identified as critical to a successful placement operation are utilization of a systems approach, establishment of…

  20. Maximize, minimize or target - optimization for a fitted response from a designed experiment

    DOE PAGESBeta

    Anderson-Cook, Christine M.; Cao, Yongtao; Michaela, Christine

    2016-04-01

    One of the common goals of running and analyzing a designed experiment is to find a location in the design space that optimizes the response of interest. Depending on the goal of the experiment, we may seek to maximize or minimize the response, or set the process to hit a particular target value. After the designed experiment, a response model is fitted and the optimal settings of the input factors are obtained based on the estimated response model. Furthermore, the suggested optimal settings of the input factors are then used in the production environment.

  1. Scaling formula of ICF ignition targets and study of targets optimized in stability performance

    NASA Astrophysics Data System (ADS)

    Li, Xin; Dai, Zhensheng; Zheng, Wudi

    2014-10-01

    LPI and RTI are the two main ingredients affecting the success of ignition. The gas fill near the Au wall along the inner laser cone is the main region which stimulates SRS instabilities. At this region, pressure balance and energy balance between the inside and the outside of inner laser cone path are obtained. A plasma scaling model in ignition hohlraums of ICF has been developed. RTI could be described by IFAR(InFlight Aspect Ratio) according to linear theory. Considering other scaling formula in capsule, a index, SPI (Stability performance Index), has been proposed, which describes the balance between SPI and RTI. Designing of ignition targets is directed by using this index to obtain more margin for LPI and RTI.

  2. Optimization of self-directed target coverage in wireless multimedia sensor network.

    PubMed

    Yang, Yang; Wang, Yufei; Pi, Dechang; Wang, Ruchuan

    2014-01-01

    Video and image sensors in wireless multimedia sensor networks (WMSNs) have directed view and limited sensing angle. So the methods to solve target coverage problem for traditional sensor networks, which use circle sensing model, are not suitable for WMSNs. Based on the FoV (field of view) sensing model and FoV disk model proposed, how expected multimedia sensor covers the target is defined by the deflection angle between target and the sensor's current orientation and the distance between target and the sensor. Then target coverage optimization algorithms based on expected coverage value are presented for single-sensor single-target, multisensor single-target, and single-sensor multitargets problems distinguishingly. Selecting the orientation that sensor rotated to cover every target falling in the FoV disk of that sensor for candidate orientations and using genetic algorithm to multisensor multitargets problem, which has NP-complete complexity, then result in the approximated minimum subset of sensors which covers all the targets in networks. Simulation results show the algorithm's performance and the effect of number of targets on the resulting subset. PMID:25136667

  3. Fuzzy optimal swarm of autonomous aircrafts for target determination and convergence control system

    NASA Astrophysics Data System (ADS)

    Richards, Zach D.

    The thesis project proposes analytical and theoretical algorithms for a networked swarm of autonomous vehicles, such as those used in planet exploration, and to be used in target location determination and convergence, an algorithm of this type could be used in an Autonomous Stratospheric Aircraft (ASA), thus having the possibility of being used for the exploration of a planet as well as many other applications. Upon locating an unknown location of a specified target, the algorithm would then swarm and eventually converge upon the location. There are two similar, but fundamentally different algorithms proposed in this project. These algorithms are capable of locating and converging upon multiple targeted locations simultaneously. This project is inspired by the current thought of NASA in the search of life on Mars, which is "Follow the Water" [18], where the targeted location would be the targeted source of water. These algorithms make use of combining a modified Particle Swarm Optimization algorithm with fuzzy variables for increased intelligence.

  4. Optimization of vascular-targeting drugs in a computational model of tumor growth

    NASA Astrophysics Data System (ADS)

    Gevertz, Jana

    2012-04-01

    A biophysical tool is introduced that seeks to provide a theoretical basis for helping drug design teams assess the most promising drug targets and design optimal treatment strategies. The tool is grounded in a previously validated computational model of the feedback that occurs between a growing tumor and the evolving vasculature. In this paper, the model is particularly used to explore the therapeutic effectiveness of two drugs that target the tumor vasculature: angiogenesis inhibitors (AIs) and vascular disrupting agents (VDAs). Using sensitivity analyses, the impact of VDA dosing parameters is explored, as is the effects of administering a VDA with an AI. Further, a stochastic optimization scheme is utilized to identify an optimal dosing schedule for treatment with an AI and a chemotherapeutic. The treatment regimen identified can successfully halt simulated tumor growth, even after the cessation of therapy.

  5. Optimal conditions for shock ignition of scaled cryogenic deuterium-tritium targets

    NASA Astrophysics Data System (ADS)

    Lafon, M.; Ribeyre, X.; Schurtz, G.

    2013-02-01

    Within the framework of the shock-ignition (SI) scheme, ignition conditions are reached following the separation of the compression and heating phases. First, the shell is compressed at a sub-ignition implosion velocity; then an intense laser spike is launched at the end of the main drive, leading to the propagation of a strong shock through the precompressed fuel. The minimal laser energy required for ignition of scaled deuterium-tritium (DT) targets is assessed by calculations. A semi-empiric model describing the ignitor shock generation and propagation in the fuel assembly is defined. The minimal power needed in the laser spike pulse to achieve ignition is derived from the hydrodynamic model. Optimal conditions for ignition of scaled targets are explored in terms of laser intensity, shell-implosion velocity, and target scale range for the SI process. Curves of minimal laser requirements for ignition are plotted in the energy-power diagram. The most economic and reliable conditions for ignition of a millimeter DT target are observed in the 240- to 320-km/s implosion velocity range and for the peak laser intensity ranging from ˜2 × 1015 W/cm2 up to 5 × 1015 W/cm2. These optimal conditions correspond to shock-ignited targets for a laser energy of ˜250 kJ and a laser power of 100 to 200 TW. Large, self-ignited targets are particularly attractive by offering ignition at a lower implosion velocity and a reduced laser intensity than for conventional ignition. The SI scheme allows for the compression and heating phases of the high power laser energy research facility target to be performed at a peak laser intensity below 1016 W/cm2. A better control of parametric and hydrodynamic instabilities within the SI scheme sets it as an optimal and reliable approach to attain ignition of large targets.

  6. Toward 3D-guided prostate biopsy target optimization: an estimation of tumor sampling probabilities

    NASA Astrophysics Data System (ADS)

    Martin, Peter R.; Cool, Derek W.; Romagnoli, Cesare; Fenster, Aaron; Ward, Aaron D.

    2014-03-01

    Magnetic resonance imaging (MRI)-targeted, 3D transrectal ultrasound (TRUS)-guided "fusion" prostate biopsy aims to reduce the ~23% false negative rate of clinical 2D TRUS-guided sextant biopsy. Although it has been reported to double the positive yield, MRI-targeted biopsy still yields false negatives. Therefore, we propose optimization of biopsy targeting to meet the clinician's desired tumor sampling probability, optimizing needle targets within each tumor and accounting for uncertainties due to guidance system errors, image registration errors, and irregular tumor shapes. We obtained multiparametric MRI and 3D TRUS images from 49 patients. A radiologist and radiology resident contoured 81 suspicious regions, yielding 3D surfaces that were registered to 3D TRUS. We estimated the probability, P, of obtaining a tumor sample with a single biopsy. Given an RMS needle delivery error of 3.5 mm for a contemporary fusion biopsy system, P >= 95% for 21 out of 81 tumors when the point of optimal sampling probability was targeted. Therefore, more than one biopsy core must be taken from 74% of the tumors to achieve P >= 95% for a biopsy system with an error of 3.5 mm. Our experiments indicated that the effect of error along the needle axis on the percentage of core involvement (and thus the measured tumor burden) was mitigated by the 18 mm core length.

  7. An optimal target-filter system for electron beam generated x-ray spectra

    SciTech Connect

    Hsu, Hsiao-Hua; Vasilik, D.G.; Chen, J.

    1994-04-01

    An electron beam generated x-ray spectrum consists of characteristic x rays of the target and continuous bremsstrahlung. The percentage of characteristic x rays over the entire energy spectrum depends on the beam energy and the filter thickness. To determine the optimal electron beam energy and filter thickness, one can either conduct many experimental measurements, or perform a series of Monte Carlo simulations. Monte Carlo simulations are shown to be an efficient tool for determining the optimal target-filter system for electron beam generated x-ray spectra. Three of the most commonly used low-energy x-ray metal targets (Cu, Zn and Mo) are chosen for this study to illustrate the power of Monte Carlo simulations.

  8. Optimal Multicarrier Phase-Coded Waveform Design for Detection of Extended Targets

    SciTech Connect

    Sen, Satyabrata; Glover, Charles Wayne

    2013-01-01

    We design a parametric multicarrier phase-coded (MCPC) waveform that achieves the optimal performance in detecting an extended target in the presence of signal-dependent interference. Traditional waveform design techniques provide only the optimal energy spectral density of the transmit waveform and suffer a performance loss in the synthesis process of the time-domain signal. Therefore, we opt for directly designing an MCPC waveform in terms of its time-frequency codes to obtain the optimal detection performance. First, we describe the modeling assumptions considering an extended target buried within the signal-dependent clutter with known power spectral density, and deduce the performance characteristics of the optimal detector. Then, considering an MCPC signal transmission, we express the detection characteristics in terms of the phase-codes of the MCPC waveform and propose to optimally design the MCPC signal by maximizing the detection probability. Our numerical results demonstrate that the designed MCPC signal attains the optimal detection performance and requires a lesser computational time than the other parametric waveform design approach.

  9. Shape optimization for DSA

    NASA Astrophysics Data System (ADS)

    Ouaknin, Gaddiel; Laachi, Nabil; Delaney, Kris; Fredrickson, Glenn; Gibou, Frederic

    2016-03-01

    Directed self-assembly using block copolymers for positioning vertical interconnect access in integrated circuits relies on the proper shape of a confined domain in which polymers will self-assemble into the targeted design. Finding that shape, i.e., solving the inverse problem, is currently mainly based on trial and error approaches. We introduce a level-set based algorithm that makes use of a shape optimization strategy coupled with self-consistent field theory to solve the inverse problem in an automated way. It is shown that optimal shapes are found for different targeted topologies with accurate placement and distances between the different components.

  10. Parameter Estimation of a Ground Moving Target Using Image Sharpness Optimization.

    PubMed

    Yu, Jing; Li, Yaan

    2016-01-01

    Motion parameter estimation of a ground moving target is an important issue in synthetic aperture radar ground moving target indication (SAR-GMTI) which has significant applications for civilian and military. The SAR image of a moving target may be displaced and defocused due to the radial and along-track velocity components, respectively. The sharpness cost function presents a measure of the degree of focus of the image. In this work, a new ground moving target parameter estimation algorithm based on the sharpness optimization criterion is proposed. The relationships between the quadratic phase errors and the target's velocity components are derived. Using two-dimensional searching of the sharpness cost function, we can obtain the velocity components of the target and the focused target image simultaneously. The proposed moving target parameter estimation method and image sharpness metrics are analyzed in detail. Finally, numerical results illustrate the effective and superior velocity estimation performance of the proposed method when compared to existing algorithms. PMID:27376294

  11. Optimal de novo design of MRM experiments for rapid assay development in targeted proteomics.

    PubMed

    Bertsch, Andreas; Jung, Stephan; Zerck, Alexandra; Pfeifer, Nico; Nahnsen, Sven; Henneges, Carsten; Nordheim, Alfred; Kohlbacher, Oliver

    2010-05-01

    Targeted proteomic approaches such as multiple reaction monitoring (MRM) overcome problems associated with classical shotgun mass spectrometry experiments. Developing MRM quantitation assays can be time consuming, because relevant peptide representatives of the proteins must be found and their retention time and the product ions must be determined. Given the transitions, hundreds to thousands of them can be scheduled into one experiment run. However, it is difficult to select which of the transitions should be included into a measurement. We present a novel algorithm that allows the construction of MRM assays from the sequence of the targeted proteins alone. This enables the rapid development of targeted MRM experiments without large libraries of transitions or peptide spectra. The approach relies on combinatorial optimization in combination with machine learning techniques to predict proteotypicity, retention time, and fragmentation of peptides. The resulting potential transitions are scheduled optimally by solving an integer linear program. We demonstrate that fully automated construction of MRM experiments from protein sequences alone is possible and over 80% coverage of the targeted proteins can be achieved without further optimization of the assay. PMID:20201589

  12. Optimization of a Multi-Stage ATR System for Small Target Identification

    NASA Technical Reports Server (NTRS)

    Lin, Tsung-Han; Lu, Thomas; Braun, Henry; Edens, Western; Zhang, Yuhan; Chao, Tien- Hsin; Assad, Christopher; Huntsberger, Terrance

    2010-01-01

    An Automated Target Recognition system (ATR) was developed to locate and target small object in images and videos. The data is preprocessed and sent to a grayscale optical correlator (GOC) filter to identify possible regionsof- interest (ROIs). Next, features are extracted from ROIs based on Principal Component Analysis (PCA) and sent to neural network (NN) to be classified. The features are analyzed by the NN classifier indicating if each ROI contains the desired target or not. The ATR system was found useful in identifying small boats in open sea. However, due to "noisy background," such as weather conditions, background buildings, or water wakes, some false targets are mis-classified. Feedforward backpropagation and Radial Basis neural networks are optimized for generalization of representative features to reduce false-alarm rate. The neural networks are compared for their performance in classification accuracy, classifying time, and training time.

  13. Design optimization of two concatenated long period waveguide grating devices for an application specific target spectrum.

    PubMed

    Semwal, Girish; Rastogi, Vipul

    2015-04-10

    We propose a global optimization method to optimize the parameters of two concatenated long period waveguide gratings (LPWGs) for generating a desired target spectrum. The design consists of two concatenated LPWGs with different grating periods inscribed in the guiding films of a four-layer planar waveguide with finite over cladding. We have used the transfer matrix method to compute the modes of the structure and the coupled mode theory to compute the spectrum of the device. The adaptive particle swarm optimization method has been used to optimize the parameters of LPWGs to generate symmetric as well as asymmetric target spectra. Two concatenated gratings of different lengths and periods have been used to generate the target spectra. To demonstrate the method of optimization we have designed a variety of wavelength filters including a rectangular shape rejection band filter, asymmetric band rejection filters, band rejection filters for flattening the amplified spontaneous emission (ASE) spectrum of an erbium doped fiber amplifier (EDFA), and a gain equalization filter for an erbium doped waveguide amplifier (EDWA) in the C-band. Seven parameters of the proposed LPWG structure have been optimized to achieve the desired spectra. We have obtained an ASE flattening with ±0.8  dB peak-to-peak ripple in case of the EDFA and gain flattening with ±0.4  dB peak-to-peak ripple in case of an EDWA. The study would be useful in the design of wavelength filters for specific applications. PMID:25967297

  14. The infrared target enhancement method based on optimization at the whole directional polarization

    NASA Astrophysics Data System (ADS)

    Zhang, Yan; Li, Ji-Cheng; Wang, Sha-fei; Gong, Ting

    2016-03-01

    An infrared target enhancement method based on optimization in the whole directional polarization is studied in this paper. By using the description relationship between the stokes vector of incident light and the intensity of emergent light, the analytical formula between the intensity of emergent light and the polarizing angle is deduced, and thus virtually derives the intensity of emergent light from 0°to 360° polarizing angle. Then according to the criterion of maximum contrast between target and background, the searching of optimal polarizing angle is iteratively realized, and finally gets the enhanced infrared target image. The feasibility and validity of the algorithm are validated by using real long wave infrared (LWIR) polarization images of target. Experimental results show that, the enhanced image using proposed algorithm possesses obvious suppression effect of background clutter, and the quantitative evaluation under two kinds of image quality evaluation indexes of average gradient and image entropy also validates the effectiveness of our algorithm in infrared target enhancement.

  15. Advanced Targeting Cost Function Design for Evolutionary Optimization of Control of Logistic Equation

    NASA Astrophysics Data System (ADS)

    Senkerik, Roman; Zelinka, Ivan; Davendra, Donald; Oplatkova, Zuzana

    2010-06-01

    This research deals with the optimization of the control of chaos by means of evolutionary algorithms. This work is aimed on an explanation of how to use evolutionary algorithms (EAs) and how to properly define the advanced targeting cost function (CF) securing very fast and precise stabilization of desired state for any initial conditions. As a model of deterministic chaotic system, the one dimensional Logistic equation was used. The evolutionary algorithm Self-Organizing Migrating Algorithm (SOMA) was used in four versions. For each version, repeated simulations were conducted to outline the effectiveness and robustness of used method and targeting CF.

  16. Optimized model of oriented-line-target detection using vertical and horizontal filters

    NASA Astrophysics Data System (ADS)

    Westland, Stephen; Foster, David H.

    1995-08-01

    A line-element target differing sufficiently in orientation from a background of line elements can be visually detected easily and quickly; orientation thresholds for such detection are lowest when the background elements are all vertical or all horizontal. A simple quantitative model of this performance was constructed from two classes of anisotropic filters, (2) nonlinear point transformation, and (3) estimation of a signal-to-noise ratio based on responses to images with and without a target. A Monte Carlo optimization procedure (simulated annealing) was used to determine the model parameter values required for providing an accurate description of psychophysical data on orientation increment thresholds.

  17. Optimal target VOI size for accurate 4D coregistration of DCE-MRI

    NASA Astrophysics Data System (ADS)

    Park, Brian; Mikheev, Artem; Zaim Wadghiri, Youssef; Bertrand, Anne; Novikov, Dmitry; Chandarana, Hersh; Rusinek, Henry

    2016-03-01

    Dynamic contrast enhanced (DCE) MRI has emerged as a reliable and diagnostically useful functional imaging technique. DCE protocol typically lasts 3-15 minutes and results in a time series of N volumes. For automated analysis, it is important that volumes acquired at different times be spatially coregistered. We have recently introduced a novel 4D, or volume time series, coregistration tool based on a user-specified target volume of interest (VOI). However, the relationship between coregistration accuracy and target VOI size has not been investigated. In this study, coregistration accuracy was quantitatively measured using various sized target VOIs. Coregistration of 10 DCE-MRI mouse head image sets were performed with various sized VOIs targeting the mouse brain. Accuracy was quantified by measures based on the union and standard deviation of the coregistered volume time series. Coregistration accuracy was determined to improve rapidly as the size of the VOI increased and approached the approximate volume of the target (mouse brain). Further inflation of the VOI beyond the volume of the target (mouse brain) only marginally improved coregistration accuracy. The CPU time needed to accomplish coregistration is a linear function of N that varied gradually with VOI size. From the results of this study, we recommend the optimal size of the VOI to be slightly overinclusive, approximately by 5 voxels, of the target for computationally efficient and accurate coregistration.

  18. Parameter Estimation of a Ground Moving Target Using Image Sharpness Optimization

    PubMed Central

    Yu, Jing; Li, Yaan

    2016-01-01

    Motion parameter estimation of a ground moving target is an important issue in synthetic aperture radar ground moving target indication (SAR-GMTI) which has significant applications for civilian and military. The SAR image of a moving target may be displaced and defocused due to the radial and along-track velocity components, respectively. The sharpness cost function presents a measure of the degree of focus of the image. In this work, a new ground moving target parameter estimation algorithm based on the sharpness optimization criterion is proposed. The relationships between the quadratic phase errors and the target’s velocity components are derived. Using two-dimensional searching of the sharpness cost function, we can obtain the velocity components of the target and the focused target image simultaneously. The proposed moving target parameter estimation method and image sharpness metrics are analyzed in detail. Finally, numerical results illustrate the effective and superior velocity estimation performance of the proposed method when compared to existing algorithms. PMID:27376294

  19. Targeted Learning of the Mean Outcome under an Optimal Dynamic Treatment Rule

    PubMed Central

    van der Laan, Mark J.; Luedtke, Alexander R.

    2015-01-01

    We consider estimation of and inference for the mean outcome under the optimal dynamic two time-point treatment rule defined as the rule that maximizes the mean outcome under the dynamic treatment, where the candidate rules are restricted to depend only on a user-supplied subset of the baseline and intermediate covariates. This estimation problem is addressed in a statistical model for the data distribution that is nonparametric beyond possible knowledge about the treatment and censoring mechanism. This contrasts from the current literature that relies on parametric assumptions. We establish that the mean of the counterfactual outcome under the optimal dynamic treatment is a pathwise differentiable parameter under conditions, and develop a targeted minimum loss-based estimator (TMLE) of this target parameter. We establish asymptotic linearity and statistical inference for this estimator under specified conditions. In a sequentially randomized trial the statistical inference relies upon a second-order difference between the estimator of the optimal dynamic treatment and the optimal dynamic treatment to be asymptotically negligible, which may be a problematic condition when the rule is based on multivariate time-dependent covariates. To avoid this condition, we also develop TMLEs and statistical inference for data adaptive target parameters that are defined in terms of the mean outcome under the estimate of the optimal dynamic treatment. In particular, we develop a novel cross-validated TMLE approach that provides asymptotic inference under minimal conditions, avoiding the need for any empirical process conditions. We offer simulation results to support our theoretical findings. PMID:26236571

  20. Constant-Envelope Waveform Design for Optimal Target-Detection and Autocorrelation Performances

    SciTech Connect

    Sen, Satyabrata

    2013-01-01

    We propose an algorithm to directly synthesize in time-domain a constant-envelope transmit waveform that achieves the optimal performance in detecting an extended target in the presence of signal-dependent interference. This approach is in contrast to the traditional indirect methods that synthesize the transmit signal following the computation of the optimal energy spectral density. Additionally, we aim to maintain a good autocorrelation property of the designed signal. Therefore, our waveform design technique solves a bi-objective optimization problem in order to simultaneously improve the detection and autocorrelation performances, which are in general conflicting in nature. We demonstrate this compromising characteristics of the detection and autocorrelation performances with numerical examples. Furthermore, in the absence of the autocorrelation criterion, our designed signal is shown to achieve a near-optimum detection performance.

  1. Methods for joint optimization of mask and design targets for improving lithographic process window

    NASA Astrophysics Data System (ADS)

    Banerjee, Shayak; Agarwal, Kanak B.; Orshansky, Michael

    2013-04-01

    Low-k1 lithography results in features that suffer from poor lithographic yield in the presence of process variation. The problem is especially pronounced for lower-level metals used for local routing, where bi-directionality and tight pitches give rise to lithography unfriendly layout patterns. However, there exists inherent unutilized flexibility in design shapes, e.g., one can modify such wires without significantly affecting design behavior. We develop two different techniques to simultaneously modify mask and design shapes during optical proximity correction (OPC) to improve lithographic yield of low-level metal layers. The methods utilize image slope information, which is available during OPC image simulations at no extra cost, as a measure of lithographic process window. We first propose a method that identifies fragments with low normalized image log slope (NILS) and then use this NILS information to guide dynamic target modification between iterations of OPC. The method uses a pre-characterized lookup table to assign a different magnitude of local target correction to different NILS bins. Next we develop an optimization flow where we derive a cost function that maximizes both contour fidelity and robustness to drive our simultaneous mask and target optimization (SMATO) method. We develop analytical equations to predict the cost for a given mask and target modification and use a fast algorithm to minimize this cost function to obtain an optimal mask and target solution. Our experiments on sample 1× (M1) layouts show that the use of SMATO reduces the process manufacturability index (PMI) by 15.4% compared with OPC, which further leads to 69% reduction in the number of layout hotspots. Additionally, such improvement is obtained at low average runtime overhead (5.5%). Compared with process window optical proximity correction (PWOPC), we observe 4.6% improvement in PMI at large (2.6×) improvement in runtime.

  2. Optimal marker-strategy clinical trial design to detect predictive markers for targeted therapy.

    PubMed

    Zang, Yong; Liu, Suyu; Yuan, Ying

    2016-07-01

    In developing targeted therapy, the marker-strategy design (MSD) provides an important approach to evaluate the predictive marker effect. This design first randomizes patients into non-marker-based or marker-based strategies. Patients allocated to the non-marker-based strategy are then further randomized to receive either the standard or targeted treatments, while patients allocated to the marker-based strategy receive treatments based on their marker statuses. Little research has been done on the statistical properties of the MSD, which has led to some widespread misconceptions and placed clinical researchers at high risk of using inefficient designs. In this article, we show that the commonly used between-strategy comparison has low power to detect the predictive effect and is valid only under a restrictive condition that the randomization ratio within the non-marker-based strategy matches the marker prevalence. We propose a Wald test that is generally valid and also uniformly more powerful than the between-strategy comparison. Based on that, we derive an optimal MSD that maximizes the power to detect the predictive marker effect by choosing the optimal randomization ratios between the two strategies and treatments. Our numerical study shows that using the proposed optimal designs can substantially improve the power of the MSD to detect the predictive marker effect. We use a lung cancer trial to illustrate the proposed optimal designs. PMID:26951724

  3. Strategies and Advancement in Antibody-Drug Conjugate Optimization for Targeted Cancer Therapeutics

    PubMed Central

    Kim, Eunhee G.; Kim, Kristine M.

    2015-01-01

    Antibody-drug conjugates utilize the antibody as a delivery vehicle for highly potent cytotoxic molecules with specificity for tumor-associated antigens for cancer therapy. Critical parameters that govern successful antibody-drug conjugate development for clinical use include the selection of the tumor target antigen, the antibody against the target, the cytotoxic molecule, the linker bridging the cytotoxic molecule and the antibody, and the conjugation chemistry used for the attachment of the cytotoxic molecule to the antibody. Advancements in these core antibody-drug conjugate technology are reflected by recent approval of Adectris® (anti-CD30-drug conjugate) and Kadcyla® (anti-HER2 drug conjugate). The potential approval of an anti-CD22 conjugate and promising new clinical data for anti-CD19 and anti-CD33 conjugates are additional advancements. Enrichment of antibody-drug conjugates with newly developed potent cytotoxic molecules and linkers are also in the pipeline for various tumor targets. However, the complexity of antibody-drug conjugate components, conjugation methods, and off-target toxicities still pose challenges for the strategic design of antibody-drug conjugates to achieve their fullest therapeutic potential. This review will discuss the emergence of clinical antibody-drug conjugates, current trends in optimization strategies, and recent study results for antibody-drug conjugates that have incorporated the latest optimization strategies. Future challenges and perspectives toward making antibody-drug conjugates more amendable for broader disease indications are also discussed. PMID:26535074

  4. Interpolating between random walks and optimal transportation routes: Flow with multiple sources and targets

    NASA Astrophysics Data System (ADS)

    Guex, Guillaume

    2016-05-01

    In recent articles about graphs, different models proposed a formalism to find a type of path between two nodes, the source and the target, at crossroads between the shortest-path and the random-walk path. These models include a freely adjustable parameter, allowing to tune the behavior of the path toward randomized movements or direct routes. This article presents a natural generalization of these models, namely a model with multiple sources and targets. In this context, source nodes can be viewed as locations with a supply of a certain good (e.g. people, money, information) and target nodes as locations with a demand of the same good. An algorithm is constructed to display the flow of goods in the network between sources and targets. With again a freely adjustable parameter, this flow can be tuned to follow routes of minimum cost, thus displaying the flow in the context of the optimal transportation problem or, by contrast, a random flow, known to be similar to the electrical current flow if the random-walk is reversible. Moreover, a source-targetcoupling can be retrieved from this flow, offering an optimal assignment to the transportation problem. This algorithm is described in the first part of this article and then illustrated with case studies.

  5. Optimization of X-ray Radiography System for Characterizing Micro-scale Targets

    NASA Astrophysics Data System (ADS)

    Flynn, Molly; Lowenstern, Mariono; Keiter, Paul; Lefevre, Heath; di Stefano, Martin; Wilson, Guy; Marion, Donna; Drake, R.

    2012-10-01

    Characterization of a target before it is shot is crucial for understanding the results obtained in high energy density experiments. We are developing a radiography system using a steady-state Manson x-ray source to better characterize these experimental targets. Due to the micro-scale of these targets, any non-uniformity in the density of target materials -- such as low-density carbon foams or plastics - could have adverse effects on experimental results. These inconsistencies are not necessarily diagnosable through other methods and thus require x-ray imaging for a more accurate analysis. We initially characterized the capabilities of our radiography system using metals of known x-ray opacity and geometric features and later expanded our subjects to include individual common target materials as well as fully fabricated targets. We present findings from a series of exposures varying flux, pinhole size, exposure time, and anode material, with the goal of optimizing resolution and magnification. This work is funded by the NNSA-DS and SC-OFES Joint Program in High-Energy-Density Laboratory Plasmas, grant number DE-FG52-09NA29548.

  6. Drug Target Optimization in Chronic Myeloid Leukemia Using Innovative Computational Platform

    NASA Astrophysics Data System (ADS)

    Chuang, Ryan; Hall, Benjamin A.; Benque, David; Cook, Byron; Ishtiaq, Samin; Piterman, Nir; Taylor, Alex; Vardi, Moshe; Koschmieder, Steffen; Gottgens, Berthold; Fisher, Jasmin

    2015-02-01

    Chronic Myeloid Leukemia (CML) represents a paradigm for the wider cancer field. Despite the fact that tyrosine kinase inhibitors have established targeted molecular therapy in CML, patients often face the risk of developing drug resistance, caused by mutations and/or activation of alternative cellular pathways. To optimize drug development, one needs to systematically test all possible combinations of drug targets within the genetic network that regulates the disease. The BioModelAnalyzer (BMA) is a user-friendly computational tool that allows us to do exactly that. We used BMA to build a CML network-model composed of 54 nodes linked by 104 interactions that encapsulates experimental data collected from 160 publications. While previous studies were limited by their focus on a single pathway or cellular process, our executable model allowed us to probe dynamic interactions between multiple pathways and cellular outcomes, suggest new combinatorial therapeutic targets, and highlight previously unexplored sensitivities to Interleukin-3.

  7. Drug Target Optimization in Chronic Myeloid Leukemia Using Innovative Computational Platform

    PubMed Central

    Chuang, Ryan; Hall, Benjamin A.; Benque, David; Cook, Byron; Ishtiaq, Samin; Piterman, Nir; Taylor, Alex; Vardi, Moshe; Koschmieder, Steffen; Gottgens, Berthold; Fisher, Jasmin

    2015-01-01

    Chronic Myeloid Leukemia (CML) represents a paradigm for the wider cancer field. Despite the fact that tyrosine kinase inhibitors have established targeted molecular therapy in CML, patients often face the risk of developing drug resistance, caused by mutations and/or activation of alternative cellular pathways. To optimize drug development, one needs to systematically test all possible combinations of drug targets within the genetic network that regulates the disease. The BioModelAnalyzer (BMA) is a user-friendly computational tool that allows us to do exactly that. We used BMA to build a CML network-model composed of 54 nodes linked by 104 interactions that encapsulates experimental data collected from 160 publications. While previous studies were limited by their focus on a single pathway or cellular process, our executable model allowed us to probe dynamic interactions between multiple pathways and cellular outcomes, suggest new combinatorial therapeutic targets, and highlight previously unexplored sensitivities to Interleukin-3. PMID:25644994

  8. Math Sense: Placement Test.

    ERIC Educational Resources Information Center

    2003

    Math Sense consists of five books that develop from basic to more advanced math skills. This document contains a placement test used with Math Sense to help students and their teachers decide into which Math Sense book to begin working. The placement test is divided into six parts, each consisting of 10 to 22 problems, and is based on exit skill…

  9. Computers and Placement.

    ERIC Educational Resources Information Center

    Devlin, Thomas; And Others

    1984-01-01

    Describes computerized placement programs at three colleges. Cornell University developed a microcomputer program while Virginia Polytechnic Institute and State University used the university's mainframe system. College of Lake County found that computerized job placement meant a stronger link with the business community. (JAC)

  10. Job Placement Primer.

    ERIC Educational Resources Information Center

    Wampler, Elizabeth C.

    The publication presents guidelines to assist secondary schools in developing and implementing a job placement service within an existing guidance program. The need for and the goals of a school placement program are given. Areas to be considered in developing a program according to one of three organizational patterns (decentralized, centralized,…

  11. Predicting targeted drug combinations based on Pareto optimal patterns of coexpression network connectivity

    PubMed Central

    2014-01-01

    Background Molecularly targeted drugs promise a safer and more effective treatment modality than conventional chemotherapy for cancer patients. However, tumors are dynamic systems that readily adapt to these agents activating alternative survival pathways as they evolve resistant phenotypes. Combination therapies can overcome resistance but finding the optimal combinations efficiently presents a formidable challenge. Here we introduce a new paradigm for the design of combination therapy treatment strategies that exploits the tumor adaptive process to identify context-dependent essential genes as druggable targets. Methods We have developed a framework to mine high-throughput transcriptomic data, based on differential coexpression and Pareto optimization, to investigate drug-induced tumor adaptation. We use this approach to identify tumor-essential genes as druggable candidates. We apply our method to a set of ER+ breast tumor samples, collected before (n = 58) and after (n = 60) neoadjuvant treatment with the aromatase inhibitor letrozole, to prioritize genes as targets for combination therapy with letrozole treatment. We validate letrozole-induced tumor adaptation through coexpression and pathway analyses in an independent data set (n = 18). Results We find pervasive differential coexpression between the untreated and letrozole-treated tumor samples as evidence of letrozole-induced tumor adaptation. Based on patterns of coexpression, we identify ten genes as potential candidates for combination therapy with letrozole including EPCAM, a letrozole-induced essential gene and a target to which drugs have already been developed as cancer therapeutics. Through replication, we validate six letrozole-induced coexpression relationships and confirm the epithelial-to-mesenchymal transition as a process that is upregulated in the residual tumor samples following letrozole treatment. Conclusions To derive the greatest benefit from molecularly targeted drugs it is

  12. Optimization of the combined proton acceleration regime with a target composition scheme

    NASA Astrophysics Data System (ADS)

    Yao, W. P.; Li, B. W.; Zheng, C. Y.; Liu, Z. J.; Yan, X. Q.; Qiao, B.

    2016-01-01

    A target composition scheme to optimize the combined proton acceleration regime is presented and verified by two-dimensional particle-in-cell simulations by using an ultra-intense circularly polarized (CP) laser pulse irradiating an overdense hydrocarbon (CH) target, instead of a pure hydrogen (H) one. The combined acceleration regime is a two-stage proton acceleration scheme combining the radiation pressure dominated acceleration (RPDA) stage and the laser wakefield acceleration (LWFA) stage sequentially together. Protons get pre-accelerated in the first stage when an ultra-intense CP laser pulse irradiating an overdense CH target. The wakefield is driven by the laser pulse after penetrating through the overdense CH target and propagating in the underdense tritium plasma gas. With the pre-accelerate stage, protons can now get trapped in the wakefield and accelerated to much higher energy by LWFA. Finally, protons with higher energies (from about 20 GeV up to about 30 GeV) and lower energy spreads (from about 18% down to about 5% in full-width at half-maximum, or FWHM) are generated, as compared to the use of a pure H target. It is because protons can be more stably pre-accelerated in the first RPDA stage when using CH targets. With the increase of the carbon-to-hydrogen density ratio, the energy spread is lower and the maximum proton energy is higher. It also shows that for the same laser intensity around 1022 W cm-2, using the CH target will lead to a higher proton energy, as compared to the use of a pure H target. Additionally, proton energy can be further increased by employing a longitudinally negative gradient of a background plasma density.

  13. Target design optimization for an electron accelerator driven subcritical facility with circular and square beam profiles.

    SciTech Connect

    Gohar, M. Y. A; Sofu, T.; Zhong, Z.; Belch, H.; Naberezhnev, D.; Nuclear Engineering Division

    2008-10-30

    A subcritical facility driven by an electron accelerator is planned at the Kharkov Institute of Physics and Technology (KIPT) in Ukraine for medical isotope production, materials research, training, and education. The conceptual design of the facility is being pursued through collaborations between ANL and KIPT. As part of the design effort, the high-fidelity analyses of various target options are performed with formulations to reflect the realistic configuration and the three dimensional geometry of each design. This report summarizes the results of target design optimization studies for electron beams with two different beam profiles. The target design optimization is performed via the sequential neutronic, thermal-hydraulic, and structural analyses for a comprehensive assessment of each configuration. First, a target CAD model is developed with proper emphasis on manufacturability to provide a basis for separate but consistent models for subsequent neutronic, thermal-hydraulic, and structural analyses. The optimizations are pursued for maximizing the neutron yield, streamlining the flow field to avoid hotspots, and minimizing the thermal stresses to increase the durability. In addition to general geometric modifications, the inlet/outlet channel configurations, target plate partitioning schemes, flow manipulations and rates, electron beam diameter/width options, and cladding material choices are included in the design optimizations. The electron beam interactions with the target assembly and the neutronic response of the subcritical facility are evaluated using the MCNPX code. the results for the electron beam energy deposition, neutron generation, and utilization in the subcritical pile are then used to characterize the axisymmetric heat generation profiles in the target assembly with explicit simulations of the beam tube, the coolant, the clad, and the target materials. Both tungsten and uranium are considered as target materials. Neutron spectra from tungsten

  14. What Are Optimal Blood Pressure Targets for Patients with Hypertension and Chronic Kidney Disease?

    PubMed

    Modi, Gopesh K; Agarwal, Rajiv

    2015-11-01

    To maximize the risk benefit ratio of blood pressure control in people with chronic kidney diseases (CKD), a number of guidelines provide recommendations on optimal blood pressure (BP) targets in CKD. This review examines these guidelines, their supporting evidence base, and generalizability and limitations of current standards of care. Over the years, the BP targets are liberalized. They now focus on the usual BP target of <140/90 mmHg. In the elderly, where guidelines call for a target of <150/90 mmHg in the general population, the recommendations provide room for the clinician to tailor therapy. Among those with albuminuria of >300 mg/g creatinine, low-quality evidence suggests targeting BP to <130/90 mmHg. Individualization of BP lowering is a key based on comorbid conditions, response to treatment, and level of kidney function. Consideration of out of clinic BP monitoring either implemented by home BP recordings or ambulatory BP measurements may enhance BP control. PMID:26374454

  15. Distributed Bees Algorithm Parameters Optimization for a Cost Efficient Target Allocation in Swarms of Robots

    PubMed Central

    Jevtić, Aleksandar; Gutiérrez, Álvaro

    2011-01-01

    Swarms of robots can use their sensing abilities to explore unknown environments and deploy on sites of interest. In this task, a large number of robots is more effective than a single unit because of their ability to quickly cover the area. However, the coordination of large teams of robots is not an easy problem, especially when the resources for the deployment are limited. In this paper, the Distributed Bees Algorithm (DBA), previously proposed by the authors, is optimized and applied to distributed target allocation in swarms of robots. Improved target allocation in terms of deployment cost efficiency is achieved through optimization of the DBA’s control parameters by means of a Genetic Algorithm. Experimental results show that with the optimized set of parameters, the deployment cost measured as the average distance traveled by the robots is reduced. The cost-efficient deployment is in some cases achieved at the expense of increased robots’ distribution error. Nevertheless, the proposed approach allows the swarm to adapt to the operating conditions when available resources are scarce. PMID:22346677

  16. Optimization of LDL targeted nanostructured lipid carriers of 5-FU by a full factorial design

    PubMed Central

    Andalib, Sare; Varshosaz, Jaleh; Hassanzadeh, Farshid; Sadeghi, Hojjat

    2012-01-01

    Background: Nanostructured lipid carriers (NLC) are a mixture of solid and liquid lipids or oils as colloidal carrier systems that lead to an imperfect matrix structure with high ability for loading water soluble drugs. The aim of this study was to find the best proportion of liquid and solid lipids of different types for optimization of the production of LDL targeted NLCs used in carrying 5-Fu by the emulsification-solvent evaporation method. Materials and Methods: The influence of the lipid type, cholesterol or cholesteryl stearate for targeting LDL receptors, oil type (oleic acid or octanol), lipid and oil% on particle size, surface charge, drug loading efficiency, and drug released percent from the NLCs were studied by a full factorial design. Results: The NLCs prepared by 54.5% cholesterol and 25% of oleic acid, showed optimum results with particle size of 105.8 nm, relatively high zeta potential of –25 mV, drug loading efficiency of 38% and release efficiency of about 40%. Scanning electron microscopy of nanoparticles confirmed the results of dynamic light scattering method used in measuring the particle size of NLCs. Conclusions: The optimization method by a full factorial statistical design is a useful optimization method for production of nanostructured lipid carriers. PMID:23326776

  17. Distributed bees algorithm parameters optimization for a cost efficient target allocation in swarms of robots.

    PubMed

    Jevtić, Aleksandar; Gutiérrez, Alvaro

    2011-01-01

    Swarms of robots can use their sensing abilities to explore unknown environments and deploy on sites of interest. In this task, a large number of robots is more effective than a single unit because of their ability to quickly cover the area. However, the coordination of large teams of robots is not an easy problem, especially when the resources for the deployment are limited. In this paper, the distributed bees algorithm (DBA), previously proposed by the authors, is optimized and applied to distributed target allocation in swarms of robots. Improved target allocation in terms of deployment cost efficiency is achieved through optimization of the DBA's control parameters by means of a genetic algorithm. Experimental results show that with the optimized set of parameters, the deployment cost measured as the average distance traveled by the robots is reduced. The cost-efficient deployment is in some cases achieved at the expense of increased robots' distribution error. Nevertheless, the proposed approach allows the swarm to adapt to the operating conditions when available resources are scarce. PMID:22346677

  18. Target point correction optimized based on the dose distribution of each fraction in daily IGRT

    NASA Astrophysics Data System (ADS)

    Stoll, Markus; Giske, Kristina; Stoiber, Eva M.; Schwarz, Michael; Bendl, Rolf

    2014-03-01

    Purpose: To use daily re-calculated dose distributions for optimization of target point corrections (TPCs) in image guided radiation therapy (IGRT). This aims to adapt fractioned intensity modulated radiation therapy (IMRT) to changes in the dose distribution induced by anatomical changes. Methods: Daily control images from an in-room on-rail spiral CT-Scanner of three head-and-neck cancer patients were analyzed. The dose distribution was re-calculated on each control CT after an initial TPC, found by a rigid image registration method. The clinical target volumes (CTVs) were transformed from the planning CT to the rigidly aligned control CTs using a deformable image registration method. If at least 95% of each transformed CTV was covered by the initially planned D95 value, the TPC was considered acceptable. Otherwise the TPC was iteratively altered to maximize the dose coverage of the CTVs. Results: In 14 (out of 59) fractions the criterion was already fulfilled after the initial TPC. In 10 fractions the TPC can be optimized to fulfill the coverage criterion. In 31 fractions the coverage can be increased but the criterion is not fulfilled. In another 4 fractions the coverage cannot be increased by the TPC optimization. Conclusions: The dose coverage criterion allows selection of patients who would benefit from replanning. Using the criterion to include daily re-calculated dose distributions in the TPC reduces the replanning rate in the analysed three patients from 76% to 59% compared to the rigid image registration TPC.

  19. Optimizing drugs to reach treatment targets for children and adolescents living with HIV

    PubMed Central

    Penazzato, Martina; Lee, Janice; Capparelli, Edmund; Essajee, Shaffiq; Ford, Nathan; Ojoo, Atieno; Pascual, Fernando; Sugandhi, Nandita; Lallemant, Marc

    2015-01-01

    Introduction As the global community makes progress towards the 90-90-90 targets by 2020, a key challenge is ensuring that antiretroviral drugs for children and adolescents are suitable to the context of resource-limited settings. Drug optimization aims to support the expanded use of more simplified, less toxic drug regimens with high barriers to drug resistance that require minimal clinical monitoring while maintaining therapeutic efficacy. This manuscript summarizes the progress made and outlines further critical steps required to ensure that the right drugs are available to start children and adolescents on treatment and to keep them virologically suppressed. Discussion Building upon previous work in drug optimization, several important steps were taken in 2014 to ensure alignment between WHO dosing recommendations and the requirements of regulatory bodies, to accelerate drug development, to reduce intellectual property barriers to generic production of combined formulations and rationalize drug selection in countries. The priority for the future is to improve access to antiretroviral therapy (ART) at the two ends of the paediatric age spectrum – infants and adolescents – where the treatment gap is greatest, and optimize drug sequencing with better use of available medicines for second- and third-line ART. Future efforts in this area will require continuous collaboration and coordination, and the promotion of innovative approaches to accelerate access to new drugs and formulations. Conclusions While significant progress has been made, additional efforts are needed to ensure that treatment targets are reached by 2020. PMID:26639117

  20. Topology of classical molecular optimal control landscapes for multi-target objectives

    SciTech Connect

    Joe-Wong, Carlee; Ho, Tak-San; Rabitz, Herschel; Wu, Rebing

    2015-04-21

    This paper considers laser-driven optimal control of an ensemble of non-interacting molecules whose dynamics lie in classical phase space. The molecules evolve independently under control to distinct final states. We consider a control landscape defined in terms of multi-target (MT) molecular states and analyze the landscape as a functional of the control field. The topology of the MT control landscape is assessed through its gradient and Hessian with respect to the control. Under particular assumptions, the MT control landscape is found to be free of traps that could hinder reaching the objective. The Hessian associated with an optimal control field is shown to have finite rank, indicating an inherent degree of robustness to control noise. Both the absence of traps and rank of the Hessian are shown to be analogous to the situation of specifying multiple targets for an ensemble of quantum states. Numerical simulations are presented to illustrate the classical landscape principles and further characterize the system behavior as the control field is optimized.

  1. Optimization of cell receptor-specific targeting through multivalent surface decoration of polymeric nanocarriers

    PubMed Central

    D’Addio, Suzanne M.; Baldassano, Steven; Shi, Lei; Cheung, Lila; Adamson, Douglas H.; Bruzek, Matthew; Anthony, John E.; Laskin, Debra L.; Sinko, Patrick J.; Prud’homme, Robert K.

    2013-01-01

    characterization of nanocarrier uptake and targeting provides promise for optimizing drug delivery to macrophages for TB treatment and establishes a general route for optimizing targeted formulations of nanocarriers for specific delivery at targeted sites. PMID:23419950

  2. Optimized beryllium target design for indirectly driven inertial confinement fusion experiments on the National Ignition Facility

    SciTech Connect

    Simakov, Andrei N. Wilson, Douglas C.; Yi, Sunghwan A.; Kline, John L.; Batha, Steven H.; Clark, Daniel S.; Milovich, Jose L.; Salmonson, Jay D.

    2014-02-15

    For indirect drive inertial confinement fusion, Beryllium (Be) ablators offer a number of important advantages as compared with other ablator materials, e.g., plastic and high density carbon. In particular, the low opacity and relatively high density of Be lead to higher rocket efficiencies giving a higher fuel implosion velocity for a given X-ray drive; and to higher ablation velocities providing more ablative stabilization and reducing the effect of hydrodynamic instabilities on the implosion performance. Be ablator advantages provide a larger target design optimization space and can significantly improve the National Ignition Facility (NIF) [J. D. Lindl et al., Phys. Plasmas 11, 339 (2004)] ignition margin. Herein, we summarize the Be advantages, briefly review NIF Be target history, and present a modern, optimized, low adiabat, Revision 6 NIF Be target design. This design takes advantage of knowledge gained from recent NIF experiments, including more realistic levels of laser-plasma energy backscatter, degraded hohlraum-capsule coupling, and the presence of cross-beam energy transfer.

  3. Exploring continuous clinical placement for undergraduate students.

    PubMed

    McKenna, Lisa G; Wray, Natalie; McCall, Louise

    2009-08-01

    Clinical placements are integral to health professional preparatory courses. These placements allow for the application of classroom-based learning into real patient care situations. In doing so, they provide opportunities for applying theoretical knowledge into practice contexts, skills development and socialisation into the chosen profession. However, despite its recognised importance across health professions, little has been written about optimal structures for supporting clinical learning. This paper presents one group of findings from a larger qualitative study aimed at exploring health professional student's clinical experiences and their impact on career intentions. Findings reported here present a group of undergraduate midwifery student's perspectives on a "home" hospital clinical placement model where continuous clinical placements were taken in the same agency (or hospital group) for 2 days per week over the final 2 years of their course. Two main themes emerged from the data analysis, these being, 'familiarity' and 'continuity'. It is concluded that continuous placements in the same clinical setting have the potential to offer greater opportunities for learning and early professional socialisation than traditional block (Monday to Friday) placements. They can offer a more integrated approach to classroom theory and its application into practice. PMID:18427942

  4. The optimal interstimulus interval and repeatability of paired associative stimulation when the soleus muscle is targeted.

    PubMed

    Kumpulainen, Susanne; Mrachacz-Kersting, Natalie; Peltonen, Jussi; Voigt, Michael; Avela, Janne

    2012-09-01

    Changes in the excitability of the cortical projections to muscles in the upper and lower limbs can be induced in the intact human by paired associative stimulation (PAS). An interstimulus interval (ISI) of 25 ms between peripheral nerve and transcranial magnetic stimuli has been found to be effective when targeting hand muscles. The optimal ISI to induce plasticity changes in the cortical projections to lower limbs is still not well established. The purpose of this study was twofold: first, to investigate the effect of PAS with four different ISIs based on the individual latency of the sensory evoked potential (SEP plus 6, 12, 18 and 24 ms) and second, to evaluate the repeatability of the established optimal ISI. Transcranial magnetic stimulation was used to measure changes in the motor evoked potentials (MEPs) of the soleus (SOL) muscle before and after the PAS interventions. Significant increases in the amplitude of SOL MEPs (88 %) were attained with an ISI of SEP latency plus 18 ms (P32 + 18 ms). The PAS effect was long-lasting, input-specific and supraspinal in origin. The intraclass correlation coefficient to test the repeatability of the PAS intervention with the optimal ISI was 0.85. The results show that the excitability of cortical projections to the soleus muscle can be repeatedly increased after PAS with an optimal ISI of SEP plus 18 ms. PMID:22836519

  5. Artificially-induced organelles are optimal targets for optical trapping experiments in living cells.

    PubMed

    López-Quesada, C; Fontaine, A-S; Farré, A; Joseph, M; Selva, J; Egea, G; Ludevid, M D; Martín-Badosa, E; Montes-Usategui, M

    2014-07-01

    Optical trapping supplies information on the structural, kinetic or rheological properties of inner constituents of the cell. However, the application of significant forces to intracellular objects is notoriously difficult due to a combination of factors, such as the small difference between the refractive indices of the target structures and the cytoplasm. Here we discuss the possibility of artificially inducing the formation of spherical organelles in the endoplasmic reticulum, which would contain densely packed engineered proteins, to be used as optimized targets for optical trapping experiments. The high index of refraction and large size of our organelles provide a firm grip for optical trapping and thereby allow us to exert large forces easily within safe irradiation limits. This has clear advantages over alternative probes, such as subcellular organelles or internalized synthetic beads. PMID:25071944

  6. Artificially-induced organelles are optimal targets for optical trapping experiments in living cells

    PubMed Central

    López-Quesada, C.; Fontaine, A.-S.; Farré, A.; Joseph, M.; Selva, J.; Egea, G.; Ludevid, M. D.; Martín-Badosa, E.; Montes-Usategui, M.

    2014-01-01

    Optical trapping supplies information on the structural, kinetic or rheological properties of inner constituents of the cell. However, the application of significant forces to intracellular objects is notoriously difficult due to a combination of factors, such as the small difference between the refractive indices of the target structures and the cytoplasm. Here we discuss the possibility of artificially inducing the formation of spherical organelles in the endoplasmic reticulum, which would contain densely packed engineered proteins, to be used as optimized targets for optical trapping experiments. The high index of refraction and large size of our organelles provide a firm grip for optical trapping and thereby allow us to exert large forces easily within safe irradiation limits. This has clear advantages over alternative probes, such as subcellular organelles or internalized synthetic beads. PMID:25071944

  7. Optimization of accelerator target and detector for portal imaging using Monte Carlo simulation and experiment

    NASA Astrophysics Data System (ADS)

    Flampouri, S.; Evans, P. M.; Verhaegen, F.; Nahum, A. E.; Spezi, E.; Partridge, M.

    2002-09-01

    Megavoltage portal images suffer from poor quality compared to those produced with kilovoltage x-rays. Several authors have shown that the image quality can be improved by modifying the linear accelerator to generate more low-energy photons. This work addresses the problem of using Monte Carlo simulation and experiment to optimize the beam and detector combination to maximize image quality for a given patient thickness. A simple model of the whole imaging chain was developed for investigation of the effect of the target parameters on the quality of the image. The optimum targets (6 mm thick aluminium and 1.6 mm copper) were installed in an Elekta SL25 accelerator. The first beam will be referred to as Al6 and the second as Cu1.6. A tissue-equivalent contrast phantom was imaged with the 6 MV standard photon beam and the experimental beams with standard radiotherapy and mammography film/screen systems. The arrangement with a thin Al target/mammography system improved the contrast from 1.4 cm bone in 5 cm water to 19% compared with 2% for the standard arrangement of a thick, high-Z target/radiotherapy verification system. The linac/phantom/detector system was simulated with the BEAM/EGS4 Monte Carlo code. Contrast calculated from the predicted images was in good agreement with the experiment (to within 2.5%). The use of MC techniques to predict images accurately, taking into account the whole imaging system, is a powerful new method for portal imaging system design optimization.

  8. A neural network-based optimization algorithm for the weapon-target assignment problem

    SciTech Connect

    Wacholder, E.

    1989-02-01

    A neural network-based algorithm was developed for the Weapon-Target Assignment Problem (WTAP) in Ballistic Missile Defense (BMD). An optimal assignment policy is one which allocates targets to weapon platforms such that the total expected leakage value of targets surviving the defense is minimized. This involves the minimization of a non-linear objective function subject to inequality constraints specifying the maximum number of interceptors available to each platform and the maximum number of interceptors allowed to be fired at each target as imposed by the Battle Management/Command Control and Communications (BM/C/sup 3/) system. The algorithm consists of solving a system of ODEs trajectories and variables. Simulations of the algorithm on PC and VAX computers were carried out using a simple numerical scheme. In all the battle instances tested, the algorithm has proven to be stable and to converge to solutions very close to global optima. The time to achieve convergence was consistently less than the time constant of the network's processing elements (neurons). This implies that fast solutions can be realized if the algorithm is implemented in hardware circuits. Three series of battle scenarios are analyzed and discussed in this report. Input data and results are presented in detail. The main advantage of this algorithm is that it can be adapted to either a special-purpose hardware circuit or a general-purpose concurrent machine to yield fast and accurate solutions to difficult decision problems. 40 refs., 8 figs., 8 tabs.

  9. Optimized ion acceleration using high repetition rate, variable thickness liquid crystal targets

    NASA Astrophysics Data System (ADS)

    Poole, Patrick; Willis, Christopher; Cochran, Ginevra; Andereck, C. David; Schumacher, Douglass

    2015-11-01

    Laser-based ion acceleration is a widely studied plasma physics topic for its applications to secondary radiation sources, advanced imaging, and cancer therapy. Recent work has centered on investigating new acceleration mechanisms that promise improved ion energy and spectrum. While the physics of these mechanisms is not yet fully understood, it has been observed to dominate for certain ranges of target thickness, where the optimum thickness depends on laser conditions including energy, pulse width, and contrast. The study of these phenomena is uniquely facilitated by the use of variable-thickness liquid crystal films, first introduced in P. L. Poole et al. PoP21, 063109 (2014). Control of the formation parameters of these freely suspended films such as volume, temperature, and draw speed allows on-demand thickness variability between 10 nanometers and several 10s of microns, fully encompassing the currently studied thickness regimes with a single target material. The low vapor pressure of liquid crystal enables in-situ film formation and unlimited vacuum use of these targets. Details on the selection and optimization of ion acceleration mechanism with target thickness will be presented, including recent experiments on the Scarlet laser facility and others. This work was performed with support from the DARPA PULSE program through a grant from AMRDEC and by the NNSA under contract DE-NA0001976.

  10. Optimizing a custom tiling microarray for low input detection and identification of unamplified virus targets.

    PubMed

    Yu, Christine; Wales, Samantha Q; Mammel, Mark K; Hida, Kaoru; Kulka, Michael

    2016-08-01

    Viruses are major pathogens causing foodborne illnesses and are often present at low levels in foods, thus requiring sensitive techniques for their detection in contaminated foods. The lack of efficient culture methods for many foodborne viruses and the potential for multi-species viral contamination have driven investigation toward non-amplification based methods for virus detection and identification. A custom DNA microarray (FDA_EVIR) was assessed for its sensitivity in the detection and identification of low-input virus targets, human hepatitis A virus, norovirus, and coxsackievirus, individually and in combination. Modifications to sample processing were made to accommodate low input levels of unamplified virus targets, which included addition of carrier cDNA, RNase treatment, and optimization of DNase I-mediated target fragmentation. Amplification-free detection and identification of foodborne viruses were achieved in the range of 250-500 copies of virus RNA. Alternative data analysis methods were employed to distinguish the genotypes of the viruses particularly at lower levels of target input and the single probe-based analysis approach made it possible to identify a minority species in a multi-virus complex. The oligonucleotide array is shown to be a promising platform to detect foodborne viruses at low levels close to what are anticipated in food or environmental samples. PMID:27033182

  11. ESL Placement and Schools

    PubMed Central

    Callahan, Rebecca; Wilkinson, Lindsey; Muller, Chandra; Frisco, Michelle

    2010-01-01

    In this study, the authors explore English as a Second Language (ESL) placement as a measure of how schools label and process immigrant students. Using propensity score matching and data from the Adolescent Health and Academic Achievement Study and the National Longitudinal Study of Adolescent Health, the authors estimate the effect of ESL placement on immigrant achievement. In schools with more immigrant students, the authors find that ESL placement results in higher levels of academic performance; in schools with few immigrant students, the effect reverses. This is not to suggest a one-size-fits-all policy; many immigrant students, regardless of school composition, generational status, or ESL placement, struggle to achieve at levels sufficient for acceptance to a 4-year university. This study offers several factors to be taken into consideration as schools develop policies and practices to provide immigrant students opportunities to learn. PMID:20617111

  12. The Placement Annual Report

    ERIC Educational Resources Information Center

    Segal, Stanley; And Others

    1970-01-01

    Two part presentation consisting, first, of study of reports indicating lack of imagination on part of placement directors, and second, of a nonstereotyped approach which puts emphasis on operating principles rather than on statistical data. (Author/CJ)

  13. Comparative study of ion acceleration by linearly polarized laser pulses from optimized targets of solid and near-critical density

    NASA Astrophysics Data System (ADS)

    Bychenkov, V. Yu; Brantov, A. V.; Govras, E. A.

    2016-03-01

    The results of a 3D optimization study of ion acceleration from ultrathin solid density foils (Brantov et al 2015 Phys. Rev. Spec. Top. Accel. Beams 18 021301) are complemented with an improved analytic model of the directed Coulomb explosion. Similarly to optimizing overdense targets, we also optimize low-density targets to obtain maximum ion energy, motivated by progress in producing a new generation of low-density slab targets whose density can be very homogeneous and as low as the relativistic critical density. Using 3D simulations, we show that for the same laser pulse, the ion energy can be significantly increased with low-density targets. A new acceleration mechanism is responsible for such an increase. This mechanism is described qualitatively, and it explains an advantage of low-density targets for high-energy ion production by lasers.

  14. Formulation, Evaluation and Optimization of Pectin- Bora Rice Beads for Colon Targeted Drug Delivery System

    PubMed Central

    Ramteke, Kuldeep Hemraj; Nath, Lilakant

    2014-01-01

    Purpose: The purpose of this research was to established new polysaccharide for the colon targeted drug delivery system, its formulation and in vitro and in vivo evaluation. Methods: Microspheres containing pectin and bora rice were prepared by ionotropic gelation technique using zinc acetate as cross linking agent and model drug used was glipizide. A 32 full factorial design was employed to study the effect of independent variables, polymer to drug ratio (A), and concentration of cross linking agent (B) on dependent variables, particle size, swelling index, drug entrapment efficiency and percentage drug release. Results: Results of trial batches indicated that polymer to drug ratio and concentration of cross linking agent affects characteristics of beads. Beads were discrete, spherical and free flowing. Beads exhibited small particle size and showed higher percentage of drug entrapment efficiency. The optimized batch P2 exhibited satisfactory drug entrapment efficiency 68% and drug release was also controlled for more than 24 hours. The polymer to drug ratio had a more significant effect on the dependent variables. In vivo gamma scintigraphy study of optimized pectin-bora rice beads demonstrated degradation of beads whenever they reached to the colon. Conclusion: Bora rice is potential polysaccharide for colon targeted drug delivery system. PMID:24511481

  15. Water quality sensor placement in water networks with budget constraints.

    SciTech Connect

    Walski, Thomas M.; Uber, James G.; Hart, William Eugene; Phillips, Cynthia Ann; Berry, Jonathan W.

    2005-02-01

    In recent years, several integer programming models have been proposed to place sensors in municipal water networks in order to detect intentional or accidental contamination. Although these initial models assumed that it is equally costly to place a sensor at any place in the network, there clearly are practical cost constraints that would impact a sensor placement decision. Such constraints include not only labor costs but also the general accessibility of a sensor placement location. In this paper, we extend our integer program to explicitly model the cost of sensor placement. We partition network locations into groups of varying placement cost, and we consider the public health impacts of contamination events under varying budget constraints. Thus our models permit cost/benefit analyses for differing sensor placement designs. As a control for our optimization experiments, we compare the set of sensor locations selected by the optimization models to a set of manually-selected sensor locations.

  16. Optimal antisense target reducing INS intron 1 retention is adjacent to a parallel G quadruplex

    PubMed Central

    Kralovicova, Jana; Lages, Ana; Patel, Alpa; Dhir, Ashish; Buratti, Emanuele; Searle, Mark; Vorechovsky, Igor

    2014-01-01

    Splice-switching oligonucleotides (SSOs) have been widely used to inhibit exon usage but antisense strategies that promote removal of entire introns to increase splicing-mediated gene expression have not been developed. Here we show reduction of INS intron 1 retention by SSOs that bind transcripts derived from a human haplotype expressing low levels of proinsulin. This haplotype is tagged by a polypyrimidine tract variant rs689 that decreases the efficiency of intron 1 splicing and increases the relative abundance of mRNAs with extended 5' untranslated region (5' UTR), which curtails translation. Co-expression of haplotype-specific reporter constructs with SSOs bound to splicing regulatory motifs and decoy splice sites in primary transcripts revealed a motif that significantly reduced intron 1-containing mRNAs. Using an antisense microwalk at a single nucleotide resolution, the optimal target was mapped to a splicing silencer containing two pseudoacceptor sites sandwiched between predicted RNA guanine (G) quadruplex structures. Circular dichroism spectroscopy and nuclear magnetic resonance of synthetic G-rich oligoribonucleotide tracts derived from this region showed formation of a stable parallel 2-quartet G-quadruplex on the 3' side of the antisense retention target and an equilibrium between quadruplexes and stable hairpin-loop structures bound by optimal SSOs. This region interacts with heterogeneous nuclear ribonucleoproteins F and H that may interfere with conformational transitions involving the antisense target. The SSO-assisted promotion of weak intron removal from the 5' UTR through competing noncanonical and canonical RNA structures may facilitate development of novel strategies to enhance gene expression. PMID:24944197

  17. Optimizing the implementation of the target motion sampling temperature treatment technique - How fast can it get?

    SciTech Connect

    Tuomas, V.; Jaakko, L.

    2013-07-01

    This article discusses the optimization of the target motion sampling (TMS) temperature treatment method, previously implemented in the Monte Carlo reactor physics code Serpent 2. The TMS method was introduced in [1] and first practical results were presented at the PHYSOR 2012 conference [2]. The method is a stochastic method for taking the effect of thermal motion into account on-the-fly in a Monte Carlo neutron transport calculation. It is based on sampling the target velocities at collision sites and then utilizing the 0 K cross sections at target-at-rest frame for reaction sampling. The fact that the total cross section becomes a distributed quantity is handled using rejection sampling techniques. The original implementation of the TMS requires 2.0 times more CPU time in a PWR pin-cell case than a conventional Monte Carlo calculation relying on pre-broadened effective cross sections. In a HTGR case examined in this paper the overhead factor is as high as 3.6. By first changing from a multi-group to a continuous-energy implementation and then fine-tuning a parameter affecting the conservativity of the majorant cross section, it is possible to decrease the overhead factors to 1.4 and 2.3, respectively. Preliminary calculations are also made using a new and yet incomplete optimization method in which the temperature of the basis cross section is increased above 0 K. It seems that with the new approach it may be possible to decrease the factors even as low as 1.06 and 1.33, respectively, but its functionality has not yet been proven. Therefore, these performance measures should be considered preliminary. (authors)

  18. Collaborative effects-based planning using adversary models and target set optimization

    NASA Astrophysics Data System (ADS)

    Pioch, Nicholas J.; Daniels, Troy; Pielech, Bradford

    2004-08-01

    The Strategy Development Tool (SDT), sponsored by AFRL-IFS, supports effects-based planning at multiple levels of war through three core capabilities: plan authoring, center of gravity (COG) modeling and analysis, and target system analysis. This paper describes recent extensions to all three of these capabilities. The extended plan authoring subsystem supports collaborative planning in which a user delegates elaboration of objectives to other registered users. A suite of collaboration tools allows planners to assign planning tasks, submit plan fragments, and review submitted plans, while a collaboration server transparently handles message routing and persistence. The COG modeling subsystem now includes an enhanced adversary modeling tool that provides a lightweight ontology for building temporal causal models relating enemy goals, beliefs, actions, and resources across multiple types of COGs. Users may overlay friendly interventions, analyze their impact on enemy COGs, and automatically incorporate the causal chains stemming from the best interventions into the current plan. Finally, the target system analysis subsystem has been extended with option generation tools that use network-based optimization algorithms to select candidate target set options to achieve specified effects.

  19. Optimization of Direct Ionization of CO2 by Controlling the Gas Flow Inside of a Beam-Target

    SciTech Connect

    Salazar Quintero, G A; Ognibene, T

    2011-03-07

    We designed and optimized a target that directs a CO{sub 2} pulse onto a Ti surface where a Cs{sup +} sputtering beam ionizes the CO{sub 2} to generate C{sup -}. These targets will be used for the direct ionization of CO{sub 2} pulses to enable the measurement of carbon isotope ratios in real time. The design was based on the results of Comsol{trademark} simulations of the target configurations.

  20. Planning a Target Renewable Portfolio using Atmospheric Modeling and Stochastic Optimization

    NASA Astrophysics Data System (ADS)

    Hart, E.; Jacobson, M. Z.

    2009-12-01

    A number of organizations have suggested that an 80% reduction in carbon emissions by 2050 is a necessary step to mitigate climate change and that decarbonization of the electricity sector is a crucial component of any strategy to meet this target. Integration of large renewable and intermittent generators poses many new problems in power system planning. In this study, we attempt to determine an optimal portfolio of renewable resources to meet best the fluctuating California load while also meeting an 80% carbon emissions reduction requirement. A stochastic optimization scheme is proposed that is based on a simplified model of the California electricity grid. In this single-busbar power system model, the load is met with generation from wind, solar thermal, photovoltaic, hydroelectric, geothermal, and natural gas plants. Wind speeds and insolation are calculated using GATOR-GCMOM, a global-through-urban climate-weather-air pollution model. Fields were produced for California and Nevada at 21km SN by 14 km WE spatial resolution every 15 minutes for the year 2006. Load data for 2006 were obtained from the California ISO OASIS database. Maximum installed capacities for wind and solar thermal generation were determined using a GIS analysis of potential development sites throughout the state. The stochastic optimization scheme requires that power balance be achieved in a number of meteorological and load scenarios that deviate from the forecasted (or modeled) data. By adjusting the error distributions of the forecasts, the model describes how improvements in wind speed and insolation forecasting may affect the optimal renewable portfolio. Using a simple model, we describe the diversity, size, and sensitivities of a renewable portfolio that is best suited to the resources and needs of California and that contributes significantly to reduction of the state’s carbon emissions.

  1. Generation of an optimal target list for the exoplanet characterisation observatory (EChO)

    NASA Astrophysics Data System (ADS)

    Varley, R.; Waldmann, I.; Pascale, E.; Tessenyi, M.; Hollis, M.; Morales, J. C.; Tinetti, G.; Swinyard, B.; Deroo, P.; Ollivier, M.; Micela, G.

    2015-12-01

    The Exoplanet Characterisation Observatory (EChO) has been studied as a space mission concept by the European Space Agency in the context of the M3 selection process. Through direct measurement of the atmospheric chemical composition of hundreds of exoplanets, EChO would address fundamental questions such as: What are exoplanets made of? How do planets form and evolve? What is the origin of exoplanet diversity? More specifically, EChO is a dedicated survey mission for transit and eclipse spectroscopy capable of observing a large, diverse and well-defined planetary sample within its four to six year mission lifetime. In this paper we use the end-to-end instrument simulator EChOSim to model the currently discovered targets, to gauge which targets are observable and assess the EChO performances obtainable for each observing tier and time. We show that EChO would be capable of observing over 170 relativity diverse planets if it were launched today, and the wealth of optimal targets for EChO expected to be discovered in the next 10 years by space and ground-based facilities is simply overwhelming. In addition, we build on previous molecular detectability studies to show what molecules and abundances will be detectable by EChO for a selection of real targets with various molecular compositions and abundances. EChO's unique contribution to exoplanetary science will be in identifying the main constituents of hundreds of exoplanets in various mass/temperature regimes, meaning that we will be looking no longer at individual cases but at populations. Such a universal view is critical if we truly want to understand the processes of planet formation and evolution in various environments. In this paper we present a selection of key results. The full results are available in Online Resource 1.

  2. Indiana Invitational Conference on Placement. Report. (Smithville, Indiana, June 25-27, 1975).

    ERIC Educational Resources Information Center

    Indiana State Board of Vocational and Technical Education, Indianapolis.

    These 10 presentations were made at a State conference to explore the problems and possibilities of job placement as background for implementing a Statewide guidance program with emphasis on counseling, placement, and followup for selected target groups. Focus is on three issues of job placement: (1) Where do the responsibilities for job placement…

  3. Optimization of the Target Subsystem for the New g-2 Experiment

    SciTech Connect

    Yoshikawa, C.; Leveling, A.; Mokhov, N.V.; Morgan, J.; Neuffer, D.; Striganov, S.; /Fermilab

    2012-05-01

    A precision measurement of the muon anomalous magnetic moment, a{sub {mu}} = (g-2)/2, was previously performed at BNL with a result of 2.2-2.7 standard deviations above the Standard Model (SM) theoretical calculations. The same experimental apparatus is being planned to run in the new Muon Campus at Fermilab, where the muon beam is expected to have less pion contamination and the extended dataset may provide a possible 7.5{sigma} deviation from the SM, creating a sensitive and complementary benchmark for proposed SM extensions. We report here on a preliminary simulation study of the target subsystem where the apparatus is optimized for pions that have favourable phase space to create polarized daughter muons around the magic momentum of 3.094 GeV/c, which is needed by the downstream g 2 muon ring.

  4. Optimization of Folate-Targeted Immunotherapy for the Treatment of Experimental Arthritis.

    PubMed

    Varghese, Bindu; Paulos, Chrystal; Low, Philip S

    2016-08-01

    Folate-targeted immunotherapy constitutes a powerful method for the treatment of established arthritis in multiple animal models of the disease. The therapy involves immunization of the animal against a hapten to induce anti-hapten antibodies, followed by injection with a folate-hapten conjugate to decorate the surface of folate receptor-positive (activated) macrophages with the antigenic hapten. The hapten-marked macrophages are then recognized by the anti-hapten antibodies and eliminated by immune mechanisms, leading to attenuation of disease symptoms. In the following paper, we optimize the therapy for elimination of inflammatory macrophages and suppression of rheumatoid arthritis symptoms. We also demonstrate a tight correlation between folate receptor-positive macrophage abundance in the liver and inflammation of affected joints. The results suggest that therapies that reduce folate receptor-positive macrophage populations in the body should constitute effective treatments for rheumatoid arthritis. PMID:27206918

  5. Optimized In Vivo Transfer of Small Interfering RNA Targeting Dermal Tissue Using In Vivo Surface Electroporation

    PubMed Central

    Broderick, Kate E; Chan, Amy; Lin, Feng; Shen, Xuefei; Kichaev, Gleb; Khan, Amir S; Aubin, Justin; Zimmermann, Tracy S; Sardesai, Niranjan Y.

    2012-01-01

    Electroporation (EP) of mammalian tissue is a technique that has been used successfully in the clinic for the delivery of genetic-based vaccines in the form of DNA plasmids. There is great interest in platforms which efficiently deliver RNA molecules such as messenger RNA and small interfering RNA (siRNA) to mammalian tissue. However, the in vivo delivery of RNA enhanced by EP has not been extensively characterized. This paper details the optimization of electrical parameters for a novel low-voltage EP method to deliver oligonucleotides (both DNA and RNA) to dermal tissue in vivo. Initially, the electrical parameters were optimized for dermal delivery of plasmid DNA encoding green fluorescent protein (GFP) using this novel surface dermal EP device. While all investigated parameters resulted in visible transfection, voltage parameters in the 10 V range elicited the most robust signal. The parameters optimized for DNA, were then assessed for translation of successful electrotransfer of siRNA into dermal tissue. Robust tagged-siRNA transfection in skin was detected. We then assessed whether these parameters translated to successful transfer of siRNA resulting in gene knockdown in vivo. Using a reporter gene construct encoding GFP and tagged siRNA targeting the GFP message, we show simultaneous transfection of the siRNA to the skin via EP and the concomitant knockdown of the reporter gene signal. The siRNA delivery was accomplished with no evidence of injection site inflammation or local tissue damage. The minimally invasive low-voltage EP method is thus capable of efficiently delivering both DNA and RNA molecules to dermal tissue in a tolerable manner. PMID:23344722

  6. Optimized in vivo transfer of small interfering RNA targeting dermal tissue using in vivo surface electroporation.

    PubMed

    Broderick, Kate E; Chan, Amy; Lin, Feng; Shen, Xuefei; Kichaev, Gleb; Khan, Amir S; Aubin, Justin; Zimmermann, Tracy S; Sardesai, Niranjan Y

    2012-01-01

    Electroporation (EP) of mammalian tissue is a technique that has been used successfully in the clinic for the delivery of genetic-based vaccines in the form of DNA plasmids. There is great interest in platforms which efficiently deliver RNA molecules such as messenger RNA and small interfering RNA (siRNA) to mammalian tissue. However, the in vivo delivery of RNA enhanced by EP has not been extensively characterized. This paper details the optimization of electrical parameters for a novel low-voltage EP method to deliver oligonucleotides (both DNA and RNA) to dermal tissue in vivo. Initially, the electrical parameters were optimized for dermal delivery of plasmid DNA encoding green fluorescent protein (GFP) using this novel surface dermal EP device. While all investigated parameters resulted in visible transfection, voltage parameters in the 10 V range elicited the most robust signal. The parameters optimized for DNA, were then assessed for translation of successful electrotransfer of siRNA into dermal tissue. Robust tagged-siRNA transfection in skin was detected. We then assessed whether these parameters translated to successful transfer of siRNA resulting in gene knockdown in vivo. Using a reporter gene construct encoding GFP and tagged siRNA targeting the GFP message, we show simultaneous transfection of the siRNA to the skin via EP and the concomitant knockdown of the reporter gene signal. The siRNA delivery was accomplished with no evidence of injection site inflammation or local tissue damage. The minimally invasive low-voltage EP method is thus capable of efficiently delivering both DNA and RNA molecules to dermal tissue in a tolerable manner. PMID:23344722

  7. Critical Path-Based Thread Placement for NUMA Systems

    SciTech Connect

    Su, C Y; Li, D; Nikolopoulos, D S; Grove, M; Cameron, K; de Supinski, B R

    2011-11-01

    Multicore multiprocessors use a Non Uniform Memory Architecture (NUMA) to improve their scalability. However, NUMA introduces performance penalties due to remote memory accesses. Without efficiently managing data layout and thread mapping to cores, scientific applications, even if they are optimized for NUMA, may suffer performance loss. In this paper, we present algorithms and a runtime system that optimize the execution of OpenMP applications on NUMA architectures. By collecting information from hardware counters, the runtime system directs thread placement and reduces performance penalties by minimizing the critical path of OpenMP parallel regions. The runtime system uses a scalable algorithm that derives placement decisions with negligible overhead. We evaluate our algorithms and runtime system with four NPB applications implemented in OpenMP. On average the algorithms achieve between 8.13% and 25.68% performance improvement compared to the default Linux thread placement scheme. The algorithms miss the optimal thread placement in only 8.9% of the cases.

  8. Toward the Optimization of Bombesin-Based Radiotracers for Tumor Targeting.

    PubMed

    Valverde, Ibai E; Vomstein, Sandra; Mindt, Thomas L

    2016-04-28

    The peptide bombesin (BBN) is a peptide with high affinity for the gastrin-releasing peptide receptor (GRPr), a receptor that is overexpressed by, for example, breast and prostate cancers. Thus, GRPr agonists can be used as cancer-targeting vectors to shuttle diagnostic and therapeutic agents into tumor cells. With the aim of optimizing the tumor targeting properties of a radiolabeled [Nle(14)]BBN(7-14) moiety, novel BBN(7-14)- and BBN(6-14)-based radioconjugates were synthesized, labeled with Lu-177, and fully evaluated in vitro and in vivo. The effect of residue and backbone modification on several parameters such as the internalization of the radiolabeled peptides into PC3 and AR42J tumor cells, their affinity toward the human GRPr, metabolic stability in blood plasma, and biodistribution in mice bearing GRPr-expressing PC3 xenografts was studied. As a result of our investigations, a novel radiolabeled GRPr agonist with a high tumor uptake and a high tumor-to-kidney ratio was identified. PMID:27054526

  9. Optimal target grasping of a flexible space manipulator for a class of objectives

    NASA Astrophysics Data System (ADS)

    Toglia, Chiara; Sabatini, Marco; Gasbarri, Paolo; Palmerini, Giovanni B.

    2011-04-01

    Space graspers are complex systems, composed by robotic arms placed on an orbiting platform. In order to fulfil the manoeuvres' requirements, it is necessary to properly model all the forces acting on the space robot. A fully nonlinear model is used to describe the dynamics, based on a multibody approach. The model includes the orbital motion, the gravity gradient, the aerodynamic effects, as well as the flexibility of the links. The present paper aims to design, thanks to nonlinear optimization algorithms, a class of manoeuvres that, given the same target to be grasped, are characterized by different mission objectives. The grasping mission can be performed with the objective to minimize the power consumption. Collision avoidance constraints can be also added when the target is equipped with solar panels or other appendices. In some cases, large elastic displacements should be expected, possibly leading to an inaccurate positioning of the end-effector. Therefore, different design strategies can require that the manoeuvre is accomplished with minimum vibrations' amplitude at the end-effector. Performance of the different strategies is analyzed in terms of control effort, trajectory errors, and flexible response of the manipulator.

  10. An Optimal t-{Delta}v Guidance Law for Intercepting a Boosting Target

    SciTech Connect

    Ng, L.C.; Breitfeller, E.; Ledebuhr, A.G.

    2002-06-30

    Lawrence Livermore National Laboratory (LLNL) have developed a new missile guidance law for intercepting a missile during boost phase. Unlike other known missile guidance laws being used today, the new t-{Delta}v guidance law optimally trades an interceptor's onboard fuel capacity against time-to-go before impact. In particular, this guidance law allows a missile designer to program the interceptor to maximally impact a boosting missile before burnout or burn termination and thus negating its ability to achieve the maximum kinetic velocity. For an intercontinental range ballistic missile (ICBM), it can be shown that for every second of earlier intercept prior to burnout, the ICBM ground range is reduced by 350 km. Therefore, intercepting a mere 15 seconds earlier would result in amiss of 5,250 km from the intended target or approximately a distance across the continental US. This paper also shows how the t-{Delta}v guidance law can incorporate uncertainties in target burnout time, predicted intercept point (PIP) error, time-to-go error, and other track estimation errors. The authors believe that the t-{Delta}v guidance law is a step toward the development of a new and smart missile guidance law that would enhance the probability of achieving a boost phase intercept.

  11. Serum Stability and Affinity Optimization of an M2 Macrophage-Targeting Peptide (M2pep).

    PubMed

    Ngambenjawong, Chayanon; Gustafson, Heather H; Pineda, Julio M; Kacherovsky, Nataly A; Cieslewicz, Maryelise; Pun, Suzie H

    2016-01-01

    Tumor associated macrophages (TAMs) are a major stromal component of the tumor microenvironment in several cancers. TAMs are a potential target for adjuvant cancer therapies due to their established roles in promoting proliferation of cancer cells, angiogenesis, and metastasis. We previously discovered an M2 macrophage-targeting peptide (M2pep) which was successfully used to target and deliver a pro-apoptotic KLA peptide to M2-like TAMs in a CT-26 colon carcinoma model. However, the effectiveness of in vivo TAM-targeting using M2pep is limited by its poor serum stability and low binding affinity. In this study, we synthesized M2pep derivatives with the goals of increasing serum stability and binding affinity. Serum stability evaluation of M2pepBiotin confirmed its rapid degradation attributed to exolytic cleavage from the N-terminus and endolytic cleavages at the W10/W11 and S16/K17 sites. N-terminal acetylation of M2pepBiotin protected the peptide against the exolytic degradation while W10w and K(17,18,19)k substitutions were able to effectively protect endolytic degradation at their respective cleavage sites. However, no tested amino acid changes at the W10 position resulted in both protease resistance at that site and retention of binding activity. Therefore, cyclization of M2pep was investigated. Cyclized M2pep better resisted serum degradation without compromising binding activity to M2 macrophages. During the serum stability optimization process, we also discovered that K9R and W10Y substitutions significantly enhanced binding affinity of M2pep. In an in vitro binding study of different M2pep analogs pre-incubated in mouse serum, cyclic M2pep with K9R and W10Y modifications (cyclic M2pep(RY)) retained the highest binding activity to M2 macrophages over time due to its improved serum stability. Finally, we evaluated the in vivo accumulation of sulfo-Cy5-labeled M2pep and cyclic M2pep(RY) in both the CT-26 and 4T1 breast carcinoma models. Cyclic M2pep

  12. Serum Stability and Affinity Optimization of an M2 Macrophage-Targeting Peptide (M2pep)

    PubMed Central

    Ngambenjawong, Chayanon; Gustafson, Heather H.; Pineda, Julio M.; Kacherovsky, Nataly A.; Cieslewicz, Maryelise; Pun, Suzie H.

    2016-01-01

    Tumor associated macrophages (TAMs) are a major stromal component of the tumor microenvironment in several cancers. TAMs are a potential target for adjuvant cancer therapies due to their established roles in promoting proliferation of cancer cells, angiogenesis, and metastasis. We previously discovered an M2 macrophage-targeting peptide (M2pep) which was successfully used to target and deliver a pro-apoptotic KLA peptide to M2-like TAMs in a CT-26 colon carcinoma model. However, the effectiveness of in vivo TAM-targeting using M2pep is limited by its poor serum stability and low binding affinity. In this study, we synthesized M2pep derivatives with the goals of increasing serum stability and binding affinity. Serum stability evaluation of M2pepBiotin confirmed its rapid degradation attributed to exolytic cleavage from the N-terminus and endolytic cleavages at the W10/W11 and S16/K17 sites. N-terminal acetylation of M2pepBiotin protected the peptide against the exolytic degradation while W10w and K(17,18,19)k substitutions were able to effectively protect endolytic degradation at their respective cleavage sites. However, no tested amino acid changes at the W10 position resulted in both protease resistance at that site and retention of binding activity. Therefore, cyclization of M2pep was investigated. Cyclized M2pep better resisted serum degradation without compromising binding activity to M2 macrophages. During the serum stability optimization process, we also discovered that K9R and W10Y substitutions significantly enhanced binding affinity of M2pep. In an in vitro binding study of different M2pep analogs pre-incubated in mouse serum, cyclic M2pep with K9R and W10Y modifications (cyclic M2pep(RY)) retained the highest binding activity to M2 macrophages over time due to its improved serum stability. Finally, we evaluated the in vivo accumulation of sulfo-Cy5-labeled M2pep and cyclic M2pep(RY) in both the CT-26 and 4T1 breast carcinoma models. Cyclic M2pep

  13. ECG-Based Detection of Early Myocardial Ischemia in a Computational Model: Impact of Additional Electrodes, Optimal Placement, and a New Feature for ST Deviation

    PubMed Central

    Loewe, Axel; Schulze, Walther H. W.; Jiang, Yuan; Wilhelms, Mathias; Luik, Armin; Dössel, Olaf; Seemann, Gunnar

    2015-01-01

    In case of chest pain, immediate diagnosis of myocardial ischemia is required to respond with an appropriate treatment. The diagnostic capability of the electrocardiogram (ECG), however, is strongly limited for ischemic events that do not lead to ST elevation. This computational study investigates the potential of different electrode setups in detecting early ischemia at 10 minutes after onset: standard 3-channel and 12-lead ECG as well as body surface potential maps (BSPMs). Further, it was assessed if an additional ECG electrode with optimized position or the right-sided Wilson leads can improve sensitivity of the standard 12-lead ECG. To this end, a simulation study was performed for 765 different locations and sizes of ischemia in the left ventricle. Improvements by adding a single, subject specifically optimized electrode were similar to those of the BSPM: 2–11% increased detection rate depending on the desired specificity. Adding right-sided Wilson leads had negligible effect. Absence of ST deviation could not be related to specific locations of the ischemic region or its transmurality. As alternative to the ST time integral as a feature of ST deviation, the K point deviation was introduced: the baseline deviation at the minimum of the ST-segment envelope signal, which increased 12-lead detection rate by 7% for a reasonable threshold. PMID:26587538

  14. Spectral optimization studies and schemes to enhance target detection and display for a three-band staring LWIR sensor

    NASA Astrophysics Data System (ADS)

    Mayer, Rulon R.; Waterman, James; Schuler, Jonathon; Scribner, Dean

    2003-12-01

    To achieve enhanced target discrimination, prototype three- band long wave infrared (LWIR) focal plane arrays (FPA) for missile defense applications have recently been constructed. The cutoff wavelengths, widths, and spectral overlap of the bands are critical parameters for the multicolor sensor design. Previous calculations for sensor design did not account for target and clutter spectral features in determining the optimal band characteristics. The considerable spectral overlap and correlation between the bands and attendant reduction in color contrast is another unexamined issue. To optimize and simulate the projected behavior of three-band sensors, this report examined a hyperspectral LWIR image cube. Our study starts with 30 bands of the LWIR spectra of three man-made targets and natural backgrounds that were binned to 3 bands using weighted band binning. This work achieves optimal binning by using a genetic algorithm approach and the target-to-clutter-ratio (TCR) as the optimization criterion. Another approach applies a genetic algorithm to maximize discrimination among the spectral reflectivities in the Non-conventional Exploitation Factors Data System (NEFDS) library. Each candidate band was weighted using a Fermi function to represent four interacting band edges for three- bands. It is found that choice of target can significantly influence the optimal choice of bands as expressed through the TCR and the Receiver Operator Characteristic curve. This study shows that whitening the image data prominently displays targets relative to backgrounds by increasing color contrast and also maintains color constancy. Three-color images are displayed by assigning red, green, blue colors directly to the whitened data set. Achieving constant colors of targets and backgrounds over time can greatly aid human viewers in the interpretation of the images and discriminate targets.

  15. Spectral optimization studies and schemes to enhance target detection and display for a three-band staring LWIR sensor

    NASA Astrophysics Data System (ADS)

    Mayer, Rulon R.; Waterman, James; Schuler, Jonathon; Scribner, Dean

    2004-01-01

    To achieve enhanced target discrimination, prototype three- band long wave infrared (LWIR) focal plane arrays (FPA) for missile defense applications have recently been constructed. The cutoff wavelengths, widths, and spectral overlap of the bands are critical parameters for the multicolor sensor design. Previous calculations for sensor design did not account for target and clutter spectral features in determining the optimal band characteristics. The considerable spectral overlap and correlation between the bands and attendant reduction in color contrast is another unexamined issue. To optimize and simulate the projected behavior of three-band sensors, this report examined a hyperspectral LWIR image cube. Our study starts with 30 bands of the LWIR spectra of three man-made targets and natural backgrounds that were binned to 3 bands using weighted band binning. This work achieves optimal binning by using a genetic algorithm approach and the target-to-clutter-ratio (TCR) as the optimization criterion. Another approach applies a genetic algorithm to maximize discrimination among the spectral reflectivities in the Non-conventional Exploitation Factors Data System (NEFDS) library. Each candidate band was weighted using a Fermi function to represent four interacting band edges for three- bands. It is found that choice of target can significantly influence the optimal choice of bands as expressed through the TCR and the Receiver Operator Characteristic curve. This study shows that whitening the image data prominently displays targets relative to backgrounds by increasing color contrast and also maintains color constancy. Three-color images are displayed by assigning red, green, blue colors directly to the whitened data set. Achieving constant colors of targets and backgrounds over time can greatly aid human viewers in the interpretation of the images and discriminate targets.

  16. Perception of Place of Articulation by Children with Cleft Palate and Posterior Placement.

    ERIC Educational Resources Information Center

    Whitehill, Tara L.; Francis, Alexander L.; Ching, Christine K-Y.

    2003-01-01

    A study examined if 10 children (ages 4-12) with repaired cleft palate who demonstrate posterior placement of alveolar targets differed from 10 children with cleft palate without such error patterns, and from 10 controls in the perception of alveolar targets. Children with posterior placement appeared unable to distinguish alveolar targets.…

  17. Assessment of Field Placement.

    ERIC Educational Resources Information Center

    Marshood, Nabil

    While field placement in human services programs is an extremely important practical phase of training, it has generally not been standardized, and thus can be difficult to assess. A model program and assessment format developed by Hudson County Community College (HCCC), in Jersey City, New Jersey, however, provides a possible framework for…

  18. Aerator Placement Strategies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The purpose of this study was to determine the effects on fish production, water quality and economics of concentrating paddlewheel aeration in large commercial ponds, compared to the current method of aerator placement. Ten 17-acre ponds (approximately 600 X 1300 ft) were brought into the study in ...

  19. Research: Hyperactivity, Placement Centers

    ERIC Educational Resources Information Center

    Nation's Schools and Colleges, 1975

    1975-01-01

    A diet that emphasizes the elimination of food containing artificial coloring and flavoring from meals served to hyperactive children has met with success in preliminary studies; college placement centers are advised to shift their emphasis from job research and counseling. (Author/MLF)

  20. Bi-objective optimization of a multiple-target active debris removal mission

    NASA Astrophysics Data System (ADS)

    Bérend, Nicolas; Olive, Xavier

    2016-05-01

    The increasing number of space debris in Low-Earth Orbit (LEO) raises the question of future Active Debris Removal (ADR) operations. Typical ADR scenarios rely on an Orbital Transfer Vehicle (OTV) using one of the two following disposal strategies: the first one consists in attaching a deorbiting kit, such as a solid rocket booster, to the debris after rendezvous; with the second one, the OTV captures the debris and moves it to a low-perigee disposal orbit. For multiple-target ADR scenarios, the design of such a mission is very complex, as it involves two optimization levels: one for the space debris sequence, and a second one for the "elementary" orbit transfer strategy from a released debris to the next one in the sequence. This problem can be seen as a Time-Dependant Traveling Salesman Problem (TDTSP) with two objective functions to minimize: the total mission duration and the total propellant consumption. In order to efficiently solve this problem, ONERA has designed, under CNES contract, TOPAS (Tool for Optimal Planning of ADR Sequence), a tool that implements a Branch & Bound method developed in previous work together with a dedicated algorithm for optimizing the "elementary" orbit transfer. A single run of this tool yields an estimation of the Pareto front of the problem, which exhibits the trade-off between mission duration and propellant consumption. We first detail our solution to cope with the combinatorial explosion of complex ADR scenarios with 10 debris. The key point of this approach is to define the orbit transfer strategy through a small set of parameters, allowing an acceptable compromise between the quality of the optimum solution and the calculation cost. Then we present optimization results obtained for various 10 debris removal scenarios involving a 15-ton OTV, using either the deorbiting kit or the disposal orbit strategy. We show that the advantage of one strategy upon the other depends on the propellant margin, the maximum duration allowed

  1. Technical advances in endoscopic ultrasound-guided fiducial placement for the treatment of pancreatic cancer

    PubMed Central

    Chavalitdhamrong, Disaya; DiMaio, Christopher J.; Siersema, Peter D.; Wagh, Mihir S.

    2015-01-01

    Radiation therapy has an important role in the treatment of locally advanced or metastatic pancreatic cancer and can be used alone or in conjunction with surgery and/or systemic chemotherapy. Because of the challenge of delivering an accurate and optimal radiation dose, image-guided radiation therapy can be used to improve targeting. Fiducial markers can be placed in the tumor and used for localization in patients undergoing image-guided radiation therapy. The safety and feasibility of endoscopic ultrasound (EUS)-guided placement of fiducials has been assessed and reported for the management of pancreatic cancer. We herein review the technique, efficacy, and safety profile of EUS-guided fiducial placement. In addition, we highlight recent advances and technological upgrades in EUS-guided fiducial delivery systems for pancreatic cancer most relevant to practicing gastroenterologists and interventional endoscopists. PMID:26355267

  2. Technical advances in endoscopic ultrasound-guided fiducial placement for the treatment of pancreatic cancer.

    PubMed

    Chavalitdhamrong, Disaya; DiMaio, Christopher J; Siersema, Peter D; Wagh, Mihir S

    2015-08-01

    Radiation therapy has an important role in the treatment of locally advanced or metastatic pancreatic cancer and can be used alone or in conjunction with surgery and/or systemic chemotherapy. Because of the challenge of delivering an accurate and optimal radiation dose, image-guided radiation therapy can be used to improve targeting. Fiducial markers can be placed in the tumor and used for localization in patients undergoing image-guided radiation therapy. The safety and feasibility of endoscopic ultrasound (EUS)-guided placement of fiducials has been assessed and reported for the management of pancreatic cancer. We herein review the technique, efficacy, and safety profile of EUS-guided fiducial placement. In addition, we highlight recent advances and technological upgrades in EUS-guided fiducial delivery systems for pancreatic cancer most relevant to practicing gastroenterologists and interventional endoscopists. PMID:26355267

  3. Comparison of optimization-algorithm based feature extraction from time data or time-frequency data for target recognition purposes

    NASA Astrophysics Data System (ADS)

    Strifors, H. C.; Abrahamson, S.; Andersson, T.; Gaunaurd, G. C.

    2006-05-01

    Ultra-wideband ground penetrating radar (GPR) systems have proved useful for extracting and displaying information for target recognition purposes. Target signatures whether in the time, frequency, or joint time-frequency domains, will substantially depend on the target's burial conditions such as the type of soil, burial depth, and the soil's moisture content. That dependence can be utilized for target recognition purposes as we have demonstrated previously. The signature template of each target was computed in the time-frequency domain from the returned echo when the target was buried at a known depth in the soil with a known moisture content. Then, for any returned echo the relative difference between the similarly computed target signature and a selected signature template was computed. A global optimization method together with our (approximate) target translation method (TTM) that signature difference, chosen as object function, was minimized by adjusting the depth and moisture content, now taken to be unknown parameters. The template that gave the smallest value of the minimized object function for the returned echo was taken as target classification and the corresponding values of the depth and moisture parameters as estimates of the target's burial conditions. This optimization technique can also be applied to time-series data, avoiding the need for time-frequency analysis. It is then of interest to evaluate the relative merits of time data and time-frequency data for target recognition. Such a comparison is here preformed using signals returned from dummy mines buried underground. The results of the analysis serve to assess the intrinsic worth of data in the time domain and in the time-frequency domain for identifying subsurface targets using a GPR. The targets are buried in a test field at the Swedish Explosive Ordnance Disposal and Demining Center (SWEDEC) at Eksjo, Sweden.

  4. Validation and assessment of integer programming sensor placement models.

    SciTech Connect

    Uber, James G.; Hart, William Eugene; Watson, Jean-Paul; Phillips, Cynthia Ann; Berry, Jonathan W.

    2005-02-01

    We consider the accuracy of predictions made by integer programming (IP) models of sensor placement for water security applications. We have recently shown that IP models can be used to find optimal sensor placements for a variety of different performance criteria (e.g. minimize health impacts and minimize time to detection). However, these models make a variety of simplifying assumptions that might bias the final solution. We show that our IP modeling assumptions are similar to models developed for other sensor placement methodologies, and thus IP models should give similar predictions. However, this discussion highlights that there are significant differences in how temporal effects are modeled for sensor placement. We describe how these modeling assumptions can impact sensor placements.

  5. Carboplatin loaded Surface modified PLGA nanoparticles: Optimization, characterization, and in vivo brain targeting studies.

    PubMed

    Jose, S; Juna, B C; Cinu, T A; Jyoti, H; Aleykutty, N A

    2016-06-01

    The carboplatin (CP) loaded poly-lactide-co-glycolide (PLGA) nanoparticles (NPs) were formulated by modified solvent evaporation method. Its surface modification is done by 1% polysorbate80 (P80) to improve their entry into the brain after intraperitoneal administration (i.p) via receptor-mediated pathways. A formulation with maximum entrapment efficiency and minimal particle size was optimized by central composite design (CCD) based on mean particle size, and entrapment efficiencies as responses. The optimized formulation was characterized by mean particle size, entrapment efficiency, zeta potential, Fourier transform infrared (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) analysis. The surface modified NPs were analysed for mean particle, zeta potential, FTIR, and in vitro release studies. The spherical particles with mean particle size 161.9nm, 162.4nm and zeta potential value of -26.5, -23.9 were obtained for unmodified and surface modified NPs respectively. The in vitro release experiments of the surface modified PLGA NPs exhibited sustained release for more than 48h, which was in accordance with Higuchi's equation with Fickian diffusion-based release mechanism. The in vivo bio distribution of P80 coated CP loaded PLGA NPs was compared with CP solution, and CP loaded NPs, in adult wistar rats. In the brain, compared with CP solution, both types of NPs especially NPs coated with P80 increased the concentration of carboplatin by 3.27 fold. All these results suggest that the developed formulation may improve the targeted therapy for malignant brain tumors in future. PMID:26970818

  6. Analyzing the multiple-target-multiple-agent scenario using optimal assignment algorithms

    SciTech Connect

    Kwok, K.S.; Driessen, B.J.; Phillips, C.A.; Tovey, C.A.

    1997-10-01

    This work considers the problem of maximum utilization of a set of mobile robots with limited sensor-range capabilities and limited travel distances. The robots are initially in random positions. A set of robots properly guards or covers a region if every point within the region is within the effective sensor range of at least one vehicle. The authors wish to move the vehicles into surveillance positions so as to guard or cover a region, while minimizing the maximum distance traveled by any vehicle. This problem can be formulated as an assignment problem, in which they must optimally decide which robot to assign to which slot of a desired matrix of grid points. The cost function is the maximum distance traveled by any robot. Assignment problems can be solved very efficiently. Solutions times for one hundred robots took only seconds on a Silicon Graphics Crimson workstation. The initial positions of all the robots can be sampled by a central base station and their newly assigned positions communicated back to the robots. Alternatively, the robots can establish their own coordinate system with the origin fixed at one of the robots and orientation determined by the compass bearing of another robot relative to this robot. This paper presents example solutions to the multiple-target-multiple-agent scenario using a matching algorithm. Two separate cases with one hundred agents in each were analyzed using this method. They have found these mobile robot problems to be a very interesting application of network optimization methods, and they expect this to be a fruitful area for future research.

  7. Construction of a directed hammerhead ribozyme library: towards the identification of optimal target sites for antisense-mediated gene inhibition.

    PubMed Central

    Pierce, M L; Ruffner, D E

    1998-01-01

    Antisense-mediated gene inhibition uses short complementary DNA or RNA oligonucleotides to block expression of any mRNA of interest. A key parameter in the success or failure of an antisense therapy is the identification of a suitable target site on the chosen mRNA. Ultimately, the accessibility of the target to the antisense agent determines target suitability. Since accessibility is a function of many complex factors, it is currently beyond our ability to predict. Consequently, identification of the most effective target(s) requires examination of every site. Towards this goal, we describe a method to construct directed ribozyme libraries against any chosen mRNA. The library contains nearly equal amounts of ribozymes targeting every site on the chosen transcript and the library only contains ribozymes capable of binding to that transcript. Expression of the ribozyme library in cultured cells should allow identification of optimal target sites under natural conditions, subject to the complexities of a fully functional cell. Optimal target sites identified in this manner should be the most effective sites for therapeutic intervention. PMID:9801305

  8. Relationship between optimal precursory disturbances and optimally growing initial errors associated with ENSO events: Implications to target observations for ENSO prediction

    NASA Astrophysics Data System (ADS)

    Hu, Junya; Duan, Wansuo

    2016-05-01

    By superimposing initial sea temperature disturbances in neutral years, we determine the precursory disturbances that are most likely to evolve into El Niño and La Niña events using an Earth System Model. These precursory disturbances for El Niño and La Niña events are deemed optimal precursory disturbances because they are more likely to trigger strong ENSO events. Specifically, the optimal precursory disturbance for El Niño exhibits negative sea surface temperature anomalies (SSTAs) in the central-eastern equatorial Pacific. Additionally, the subsurface temperature component exhibits negative anomalies in the upper layers of the eastern equatorial Pacific and positive anomalies in the lower layers of the western equatorial Pacific. The optimal precursory disturbance for La Niña is almost opposite to that of El Niño. The optimal precursory disturbances show that both El Niño and La Niña originate from precursory signals in the subsurface layers of the western equatorial Pacific and in the surface layers of the eastern equatorial Pacific. We find that the optimal precursory disturbances for El Niño and La Niña are particularly similar to the optimally growing initial errors associated with El Niño prediction that have been presented in previous studies. The optimally growing initial errors show that the optimal precursor source areas represent the sensitive areas for target observations associated with ENSO prediction. Combining the optimal precursory disturbances and the optimally growing initial errors for ENSO, we infer that additional observations in these sensitive areas can reduce initial errors and be used to detect precursory signals, thereby improving ENSO predictions.

  9. Characterizing and optimizing human anticancer drug targets based on topological properties in the context of biological pathways.

    PubMed

    Zhang, Jian; Wang, Yan; Shang, Desi; Yu, Fulong; Liu, Wei; Zhang, Yan; Feng, Chenchen; Wang, Qiuyu; Xu, Yanjun; Liu, Yuejuan; Bai, Xuefeng; Li, Xuecang; Li, Chunquan

    2015-04-01

    One of the challenging problems in drug discovery is to identify the novel targets for drugs. Most of the traditional methods for drug targets optimization focused on identifying the particular families of "druggable targets", but ignored their topological properties based on the biological pathways. In this study, we characterized the topological properties of human anticancer drug targets (ADTs) in the context of biological pathways. We found that the ADTs tended to present the following seven topological properties: influence the number of the pathways related to cancer, be localized at the start or end of the pathways, interact with cancer related genes, exhibit higher connectivity, vulnerability, betweenness, and closeness than other genes. We first ranked ADTs based on their topological property values respectively, then fused them into one global-rank using the joint cumulative distribution of an N-dimensional order statistic to optimize human ADTs. We applied the optimization method to 13 anticancer drugs, respectively. Results demonstrated that over 70% of known ADTs were ranked in the top 20%. Furthermore, the performance for mercaptopurine was significant: 6 known targets (ADSL, GMPR2, GMPR, HPRT1, AMPD3, AMPD2) were ranked in the top 15 and other four out of the top 15 (MAT2A, CDKN1A, AREG, JUN) have the potentialities to become new targets for cancer therapy. PMID:25724580

  10. Highly optimized DNA vaccine targeting human telomerase reverse transcriptase stimulates potent antitumor immunity

    PubMed Central

    Shin, Thomas H.; Obeng-Adjei, Nyamekye; Morrow, Matthew P.; Walters, Jewell N.; Khan, Amir S.; Sardesai, Niranjan Y.; Weiner, David B.

    2014-01-01

    High levels of human Telomerase Reverse Transcriptase (hTERT) are detected in over 85% of human cancers. Immunological analysis supports hTERT is a widely applicable target recognized by T cells and can be potentially studied as a broad cancer immune therapeutic, or a unique line of defense against tumor recurrence. There remains an urgent need to develop more potent hTERT vaccines. Here, a synthetic highly optimized full-length hTERT DNA vaccine (phTERT) was designed and the induced immunity was examined in mice and non-human primates. When delivered by electroporation, phTERT elicited strong, broad hTERT-specific CD8 responses including induction of T-cells expressing CD107a, IFN-γ and TNF-α in mice. The ability of phTERT to overcome tolerance was evaluated in a NHP model, whose TERT is 96% homologous to that of hTERT. Immunized monkeys exhibited robust (average 1834 SFU/106 PBMCs), diverse (multiple immunodominant epitopes) IFN-γ responses and antigen-specific perforin release (average 332 SFU/106 PBMCs), suggesting phTERT breaks tolerance and induces potent cytotoxic responses in this human relevant model. Moreover, in an HPV16-associated tumor model, vaccination of phTERT slows tumor growth and improves survival rate in both prophylactic and therapeutic studies. Lastly, in vivo cytotoxicity assay confirmed that phTERT-induced CD8 T cells exhibited specific CTL activity, capable of eliminating hTERT-pulsed target cells. These findings support that this synthetic EP-delivered DNA phTERT may have a role as a broad therapeutic cancer vaccine candidate. PMID:24777680

  11. VLSI Cells Placement Using the Neural Networks

    SciTech Connect

    Azizi, Hacene; Zouaoui, Lamri; Mokhnache, Salah

    2008-06-12

    The artificial neural networks have been studied for several years. Their effectiveness makes it possible to expect high performances. The privileged fields of these techniques remain the recognition and classification. Various applications of optimization are also studied under the angle of the artificial neural networks. They make it possible to apply distributed heuristic algorithms. In this article, a solution to placement problem of the various cells at the time of the realization of an integrated circuit is proposed by using the KOHONEN network.

  12. Balanced Placement Of Vibration Sensors And Actuators

    NASA Technical Reports Server (NTRS)

    Gawronski, Wodek

    1996-01-01

    Mathematical approach that involves Hankel singular values leads to method for estimation of optimal placement of relatively few vibration sensors and actuators in multivariable flexible structure. Approach extends and complements previous developments regarding approximate decomposition, to Hankel singular values, of singular values of controllability and observability grammian matrices of multivariable flexible structure. Mathematical constructs also described in "Designing An Approximately Balanced LQG Compensator" (NPO-19000).

  13. Discovery and synthetic optimization of a novel scaffold for hydrophobic tunnel-targeted autotaxin inhibition.

    PubMed

    Ragle, Lauren E; Palanisamy, Dilip J; Joe, Margaux J; Stein, Rachel S; Norman, Derek D; Tigyi, Gabor; Baker, Daniel L; Parrill, Abby L

    2016-10-01

    Autotaxin (ATX) is a ubiquitous ectoenzyme that hydrolyzes lysophosphatidylcholine (LPC) to form the bioactive lipid mediator lysophosphatidic acid (LPA). LPA activates specific G-protein coupled receptors to elicit downstream effects leading to cellular motility, survival, and invasion. Through these pathways, upregulation of ATX is linked to diseases such as cancer and cardiovascular disease. Recent crystal structures confirm that the catalytic domain of ATX contains multiple binding regions including a polar active site, hydrophobic tunnel, and a hydrophobic pocket. This finding is consistent with the promiscuous nature of ATX hydrolysis of multiple and diverse substrates and prior investigations of inhibitor impacts on ATX enzyme kinetics. The current study used virtual screening methods to guide experimental identification and characterization of inhibitors targeting the hydrophobic region of ATX. An initially discovered inhibitor, GRI392104 (IC50 4μM) was used as a lead for synthetic optimization. In total twelve newly synthesized inhibitors of ATX were more potent than GRI392104 and were selective for ATX as they had no effect on other LPC-specific NPP family members or on LPA1-5 GPCR. PMID:27544588

  14. Improved Plant-based Production of E1 endoglucanase Using Potato: Expression Optimization and Tissue Targeting

    SciTech Connect

    Dai, Ziyu; Hooker, Brian S.; Anderson, Daniel B.; Thomas, Steven R.

    2000-06-01

    Optimization of Acidothermus cellulolyticus endoglucanase (E1) gene expression in transgenic potato (Solanum tuberosum L.) was examined in this study, where the E1 coding sequence was transcribed under control of a leaf specific promoter (tomato RbcS-3C) or the Mac promoter (a hybrid promoter of mannopine synthase promoter and cauliflower mosaic virus 35S promoter enhancer region). Average E1 activity in leaf extracts of potato transformants, in which E1 protein was targeted by a chloroplast signal peptide and an apoplast signal peptide were much higher than those by an E1 native signal peptide and a vacuole signal peptide. E1 protein accumulated up to 2.6% of total leaf soluble protein, where E1 gene was under control of the RbcS-3C promoter, alfalfa mosaic virus 5-untranslated leader, and RbcS-2A signal peptide. E1 protein production, based on average E1 activity and E1 protein accumulation in leaf extracts, is higher in potato than those measured previously in transgenic tobacco bearing the same transgene constructs. Comparisons of E1 activity, protein accumulation, and relative mRNA levels showed that E1 expression under control of tomato RbcS-3C promoter was specifically localized in leaf tissues, while E1 gene was expressed in both leaf and tuber tissues under control of Mac promoter. This suggests dual-crop applications in which potato vines serve as enzyme production `bioreactors' while tubers are preserved for culinary applications.

  15. An approach to optimal hyperspectral and multispectral signature and image fusion for detecting hidden targets on shorelines

    NASA Astrophysics Data System (ADS)

    Bostater, Charles R.

    2015-10-01

    Hyperspectral and multispectral imagery of shorelines collected from airborne and shipborne platforms are used following pushbroom imagery corrections using inertial motion motions units and augmented global positioning data and Kalman filtering. Corrected radiance or reflectance images are then used to optimize synthetic high spatial resolution spectral signatures resulting from an optimized data fusion process. The process demonstrated utilizes littoral zone features from imagery acquired in the Gulf of Mexico region. Shoreline imagery along the Banana River, Florida, is presented that utilizes a technique that makes use of numerically embedded targets in both higher spatial resolution multispectral images and lower spatial resolution hyperspectral imagery. The fusion process developed utilizes optimization procedures that include random selection of regions and pixels in the imagery, and minimizing the difference between the synthetic signatures and observed signatures. The optimized data fusion approach allows detection of spectral anomalies in the resolution enhanced data cubes. Spectral-spatial anomaly detection is demonstrated using numerically embedded line targets within actual imagery. The approach allows one to test spectral signature anomaly detection and to identify features and targets. The optimized data fusion techniques and software allows one to perform sensitivity analysis and optimization in the singular value decomposition model building process and the 2-D Butterworth cutoff frequency and order numerical selection process. The data fusion "synthetic imagery" forms a basis for spectral-spatial resolution enhancement for optimal band selection and remote sensing algorithm development within "spectral anomaly areas". Sensitivity analysis demonstrates the data fusion methodology is most sensitive to (a) the pixels and features used in the SVD model building process and (b) the 2-D Butterworth cutoff frequency optimized by application of K

  16. Hard target penetrator explosive development optimization of fragment, blast and survivability properties of explosives for hard target applications

    SciTech Connect

    Simpson, R. L., LLNL

    1997-05-01

    Several new explosives have been developed for hard target and related applications. Materials having energy densities as high as 20 KJ/cc have been made. Mid-scale field trials have been carried out at Eglin Air Force Base. Fragmentation improvements 150% that of Tritonal have been attained.

  17. Back to the Future: Lessons Learned in Modern Target-based and Whole-Cell Lead Optimization of Antimalarials

    PubMed Central

    Chatterjee, Arnab K; Yeung, Bryan KS

    2012-01-01

    Antimalarial drug discovery has historically benefited from the whole-cell (phenotypic) screening approach to identify lead molecules in the search for new drugs. However over the past two decades there has been a shift in the pharmaceutical industry to move away from whole-cell screening to target-based approaches. As part of a Wellcome Trust and Medicines for Malaria Venture (MMV) funded consortium to discover new blood-stage antimalarials, we used both approaches to identify new antimalarial chemotypes, two of which have progressed beyond the lead optimization phase and display excellent in vivo efficacy in mice. These two advanced series were identified through a cell-based optimization devoid of target information and in this review we summarize the advantages of this approach versus a target-based optimization. Although the each lead optimization required slightly different medicinal chemistry strategies, we observed some common issues across the different the scaffolds which could be applied to other cell based lead optimization programs. PMID:22242845

  18. Placement Of Exciters And Sensors To Measure Vibrations

    NASA Technical Reports Server (NTRS)

    Salama, Moktar A.; Rose, Theodore L.; Garba, John A.

    1989-01-01

    Report discusses use of simulated-annealing algorithm to place exciters and sensors of vibrations at nearly optimal positions in complicated structure. Because there are generally fewer exciters and sensors than degrees of freedom in structure, optimal-placement algorithm needed to maximize value of resulting incomplete set of measurements for verification of amplitudes and frequencies of previously-computed vibrational modes.

  19. Optimization of targeted two-photon PDT triads for the treatment of head and neck cancers

    NASA Astrophysics Data System (ADS)

    Spangler, Charles W.; Starkey, Jean R.; Dubinina, Galyna; Fahlstrom, Carl; Shepard, Joyce

    2012-02-01

    Synthesis of new PDT triads that incorporate a tumor-killing porphyrin with large two-photon cross-section for 150 fs laser pulses (2000 GM) in the Near-infrared (NIR) at 840 nm, a NIR imaging agent, and a small peptide that targets over-expressed EGF receptors on the tumor surface. This triad formulation has been optimized over the past year to treat FADU Head and Neck SCC xenograft tumors in SCID mice. Effective PDT triad dose (1-10 mg/Kg) and laser operating parameters (840 nm, 15-45 min, 900 mW) have been established. Light, dark and PDT treatment toxicities were determined, showing no adverse effects. Previous experiments in phantom and mouse models indicate that tumors can be treated directly through the skin to effective depths between 2 and 5 cm. Treated mice demonstrated rapid tumor regression with some complete cures in as little as 15-20 days. No adverse effects were observed in any healthy tissue through which the focused laser beam passed before reaching the tumor site, and excellent healing occurred post treatment including rapid hair re-growth. Not all irradiation protocols lead to complete cures. Since two-photon PDT is carried out by rastering focused irradiation throughout the tumor, there is the possibility that as the treatment depth increases, some parts of the tumor may escape irradiation due to increased scattering, thus raising the possibility that tumor re-growth could be triggered by small islands of untreated cells, especially at the rapidly growing tumor margins, a problem we hope to alleviate by using image-guided two-photon PDT.

  20. Optimization of substrate-target distance for pulsed laser deposition of tungsten oxide thin films using Langmuir probe

    NASA Astrophysics Data System (ADS)

    Panda, A. Kumar; Singh, A.; Thirumurugesan, R.; Kuppusami, P.; Mohandas, E.

    2015-09-01

    The paper investigates the spatial and temporal variation of laser produced plasma of tungsten oxide using a Langmuir probe. The plasma was produced by laser ablation of tungsten oxide target using an Excimer laser of wavelength 248 nm. Our experimental studies confirmed that oxygen partial pressure (P) of 2× 10-2 mbar is sufficient enough to get stoichiometric tungsten oxide thin films and the plume dynamics was diagnosed for their spatial and temporal behaviour at the above optimised oxygen pressure. Spatial distribution was recorded with the target to substrate distance (D) ranging from the target position to a distance of 75 mm away from the target, whereas the temporal variation was taken in the range of 0-50 μ S with an interval of 0.5 μ S. The average electron densities were found to be maximum at 30 mm from the target position. However, ion density was constant beyond the probe distance of 45 mm from the target. The plasma current was found to be maximum at 28 μ S. The target to substrate distance was optimized for homogenous adherent good quality thin films using plasma parameters such as ion density and average electron density obtained at different oxygen pressure. The target distance and background gas pressure were correlated as PD scaling law and fitted as PD3 in the model.

  1. Colon specific CODES based Piroxicam tablet for colon targeting: statistical optimization, in vivo roentgenography and stability assessment.

    PubMed

    Singh, Amit Kumar; Pathak, Kamla

    2015-03-01

    This study was aimed to statistically optimize CODES™ based Piroxicam (PXM) tablet for colon targeting. A 3(2) full factorial design was used for preparation of core tablet that was subsequently coated to get CODES™ based tablet. The experimental design of core tablets comprised of two independent variables: amount of lactulose and PEG 6000, each at three different levels and the dependent variable was %CDR at 12 h. The core tablets were evaluated for pharmacopoeial and non-pharmacopoeial test and coated with optimized levels of Eudragit E100 followed by HPMC K15 and finally with Eudragit S100. The in vitro drug release study of F1-F9 was carried out by change over media method (0.1 N HCl buffer, pH 1.2, phosphate buffer, pH 7.4 and phosphate buffer, pH 6.8 with enzyme β-galactosidase 120 IU) to select optimized formulation F9 that was subjected to in vivo roentgenography. Roentgenography study corroborated the in vitro performance, thus providing the proof of concept. The experimental design was validated by extra check point formulation and Diffuse Reflectance Spectroscopy revealed absence of any interaction between drug and formulation excipients. The shelf life of F9 was deduced as 12 months. Conclusively, colon targeted CODES™ technology based PXM tablets were successfully optimized and its potential of colon targeting was validated by roentgenography. PMID:24266719

  2. Optimal selection and placement of green infrastructure to reduce impacts of land use change and climate change on hydrology and water quality: An application to the Trail Creek Watershed, Indiana.

    PubMed

    Liu, Yaoze; Theller, Lawrence O; Pijanowski, Bryan C; Engel, Bernard A

    2016-05-15

    The adverse impacts of urbanization and climate change on hydrology and water quality can be mitigated by applying green infrastructure practices. In this study, the impacts of land use change and climate change on hydrology and water quality in the 153.2km(2) Trail Creek watershed located in northwest Indiana were estimated using the Long-Term Hydrologic Impact Assessment-Low Impact Development 2.1 (L-THIA-LID 2.1) model for the following environmental concerns: runoff volume, Total Suspended Solids (TSS), Total Phosphorous (TP), Total Kjeldahl Nitrogen (TKN), and Nitrate+Nitrite (NOx). Using a recent 2001 land use map and 2050 land use forecasts, we found that land use change resulted in increased runoff volume and pollutant loads (8.0% to 17.9% increase). Climate change reduced runoff and nonpoint source pollutant loads (5.6% to 10.2% reduction). The 2050 forecasted land use with current rainfall resulted in the largest runoff volume and pollutant loads. The optimal selection and placement of green infrastructure practices using L-THIA-LID 2.1 model were conducted. Costs of applying green infrastructure were estimated using the L-THIA-LID 2.1 model considering construction, maintenance, and opportunity costs. To attain the same runoff volume and pollutant loads as in 2001 land uses for 2050 land uses, the runoff volume, TSS, TP, TKN, and NOx for 2050 needed to be reduced by 10.8%, 14.4%, 13.1%, 15.2%, and 9.0%, respectively. The corresponding annual costs of implementing green infrastructure to achieve the goals were $2.1, $0.8, $1.6, $1.9, and $0.8 million, respectively. Annual costs of reducing 2050 runoff volume/pollutant loads were estimated, and results show green infrastructure annual cost greatly increased for larger reductions in runoff volume and pollutant loads. During optimization, the most cost-efficient green infrastructure practices were selected and implementation levels increased for greater reductions of runoff and nonpoint source pollutants

  3. Optimized DNA-targeting using triplex forming C5-alkynyl functionalized LNA.

    PubMed

    Sau, Sujay P; Kumar, Pawan; Anderson, Brooke A; Østergaard, Michael E; Deobald, Lee; Paszczynski, Andrzej; Sharma, Pawan K; Hrdlicka, Patrick J

    2009-11-28

    Triplex forming oligonucleotides (TFOs) modified with C5-alkynyl functionalized LNA (locked nucleic acid) monomers display extraordinary thermal affinity toward double stranded DNA targets, excellent discrimination of Hoogsteen-mismatched targets, and high stability against 3?-exonucleases. PMID:19885469

  4. Optimizing MRI-targeted fusion prostate biopsy: the effect of systematic error and anisotropy on tumor sampling

    NASA Astrophysics Data System (ADS)

    Martin, Peter R.; Cool, Derek W.; Romagnoli, Cesare; Fenster, Aaron; Ward, Aaron D.

    2015-03-01

    Magnetic resonance imaging (MRI)-targeted, 3D transrectal ultrasound (TRUS)-guided "fusion" prostate biopsy aims to reduce the 21-47% false negative rate of clinical 2D TRUS-guided sextant biopsy. Although it has been reported to double the positive yield, MRI-targeted biopsy still has a substantial false negative rate. Therefore, we propose optimization of biopsy targeting to meet the clinician's desired tumor sampling probability, optimizing needle targets within each tumor and accounting for uncertainties due to guidance system errors, image registration errors, and irregular tumor shapes. As a step toward this optimization, we obtained multiparametric MRI (mpMRI) and 3D TRUS images from 49 patients. A radiologist and radiology resident contoured 81 suspicious regions, yielding 3D surfaces that were registered to 3D TRUS. We estimated the probability, P, of obtaining a tumor sample with a single biopsy, and investigated the effects of systematic errors and anisotropy on P. Our experiments indicated that a biopsy system's lateral and elevational errors have a much greater effect on sampling probabilities, relative to its axial error. We have also determined that for a system with RMS error of 3.5 mm, tumors of volume 1.9 cm3 and smaller may require more than one biopsy core to ensure 95% probability of a sample with 50% core involvement, and tumors 1.0 cm3 and smaller may require more than two cores.

  5. Treatment Optimization Using Computed Tomography-Delineated Targets Should be Used for Supraclavicular Irradiation for Breast Cancer

    SciTech Connect

    Liengsawangwong, Raweewan; Yu, T.-K.; Sun, T.-L.; Erasmus, Jeremy J.; Perkins, George H.; Tereffe, Welela; Oh, Julia L.; Woodward, Wendy A.; Strom, Eric A.; Salephour, Mohammad; Buchholz, Thomas A.

    2007-11-01

    Background: The purpose of this study was to determine whether the use of optimized CT treatment planning offered better coverage of axillary level III (LIII)/supraclavicular (SC) targets than the empirically derived dose prescription that are commonly used. Materials/Methods: Thirty-two consecutive breast cancer patients who underwent CT treatment planning of a SC field were evaluated. Each patient was categorized according to body mass index (BMI) classes: normal, overweight, or obese. The SC and LIII nodal beds were contoured, and four treatment plans for each patient were generated. Three of the plans used empiric dose prescriptions, and these were compared with a CT-optimized plan. Each plan was evaluated by two criteria: whether 98% of target volume receive >90% of prescribed dose and whether < 5% of the irradiated volume received 105% of prescribed dose. Results: The mean depth of SC and LIII were 3.2 cm (range, 1.4-6.7 cm) and 3.1 (range, 1.7-5.8 cm). The depth of these targets varied according across BMI classes (p = 0.01). Among the four sets of plans, the CT-optimized plans were the most successful at achieving both of the dosimetry objectives for every BMI class (normal BMI, p = .003; overweight BMI, p < .0001; obese BMI, p < .001). Conclusions: Across all BMI classes, routine radiation prescriptions did not optimally cover intended targets for every patient. Optimized CT-based treatment planning generated the most successful plans; therefore, we recommend the use of routine CT simulation and treatment planning of SC fields in breast cancer.

  6. Optimizing Restriction Site Placement for Synthetic Genomes

    NASA Astrophysics Data System (ADS)

    Montes, Pablo; Memelli, Heraldo; Ward, Charles; Kim, Joondong; Mitchell, Joseph S. B.; Skiena, Steven

    Restriction enzymes are the workhorses of molecular biology. We introduce a new problem that arises in the course of our project to design virus variants to serve as potential vaccines: we wish to modify virus-length genomes to introduce large numbers of unique restriction enzyme recognition sites while preserving wild-type function by substitution of synonymous codons. We show that the resulting problem is NP-Complete, give an exponential-time algorithm, and propose effective heuristics, which we show give excellent results for five sample viral genomes. Our resulting modified genomes have several times more unique restriction sites and reduce the maximum gap between adjacent sites by three to nine-fold.

  7. Sensor networks for optimal target localization with bearings-only measurements in constrained three-dimensional scenarios.

    PubMed

    Moreno-Salinas, David; Pascoal, Antonio; Aranda, Joaquin

    2013-01-01

    In this paper, we address the problem of determining the optimal geometric configuration of an acoustic sensor network that will maximize the angle-related information available for underwater target positioning. In the set-up adopted, a set of autonomous vehicles carries a network of acoustic units that measure the elevation and azimuth angles between a target and each of the receivers on board the vehicles. It is assumed that the angle measurements are corrupted by white Gaussian noise, the variance of which is distance-dependent. Using tools from estimation theory, the problem is converted into that of minimizing, by proper choice of the sensor positions, the trace of the inverse of the Fisher Information Matrix (also called the Cramer-Rao Bound matrix) to determine the sensor configuration that yields the minimum possible covariance of any unbiased target estimator. It is shown that the optimal configuration of the sensors depends explicitly on the intensity of the measurement noise, the constraints imposed on the sensor configuration, the target depth and the probabilistic distribution that defines the prior uncertainty in the target position. Simulation examples illustrate the key results derived. PMID:23941912

  8. Sensor Networks for Optimal Target Localization with Bearings-Only Measurements in Constrained Three-Dimensional Scenarios

    PubMed Central

    Moreno-Salinas, David; Pascoal, Antonio; Aranda, Joaquin

    2013-01-01

    In this paper, we address the problem of determining the optimal geometric configuration of an acoustic sensor network that will maximize the angle-related information available for underwater target positioning. In the set-up adopted, a set of autonomous vehicles carries a network of acoustic units that measure the elevation and azimuth angles between a target and each of the receivers on board the vehicles. It is assumed that the angle measurements are corrupted by white Gaussian noise, the variance of which is distance-dependent. Using tools from estimation theory, the problem is converted into that of minimizing, by proper choice of the sensor positions, the trace of the inverse of the Fisher Information Matrix (also called the Cramer-Rao Bound matrix) to determine the sensor configuration that yields the minimum possible covariance of any unbiased target estimator. It is shown that the optimal configuration of the sensors depends explicitly on the intensity of the measurement noise, the constraints imposed on the sensor configuration, the target depth and the probabilistic distribution that defines the prior uncertainty in the target position. Simulation examples illustrate the key results derived. PMID:23941912

  9. Investigation of the optimal material type and dimension for spallation targets using simulation methods

    NASA Astrophysics Data System (ADS)

    Feghhi, Seyed Amir Hossein; Gholamzadeh, Zohreh; Tenreiro, Claudio

    2014-01-01

    Accelerator-driven systems are extensively developed to generate neutron sources for research, industrial, and medical plans. Different heavy elements are utilized as spallation targets to produce spallation neutrons. Computational methods are efficiently utilized to simulate neutronic behavior of a spallation target. MCNPX 2.6.0 is used as a powerful code based on Monte Carlo stochastic techniques for spallation process computation. This code has the ability to transport different particles using different physical models. In this paper, MCNPX has been utilized to calculate the leaked neutron yield from Pb, lead-bismuth eutectic (LBE), W, Ta, Hg, U, Th, Sn, and Cu cylindrical heavy targets. The effects of the target thickness and diameter on neutron yield value have been investigated via the thickness and diameter variations between 5 to 30 cm and 5 to 20 cm, respectively. Proton-induced radionuclide production into the targets as well as leaked neutron spectra from the targets has been calculated for the targets of an optimum determined dimension. The 1-GeV proton particle has been selected to induce spallation process inside the targets. The 2-mm spatial FWHM distribution has been considered for the 1-mA proton beam. Uranium target produced the highest leaked neutron yield with a 1.32 to 3.7 factor which overweighs the others. A dimension of 15 × 60 cm is suggested for all the cylindrical studied spallation targets. Th target experienced the highest alpha emitter radionuclide production while lighter elements such as Cu and Sn bore the lowest radiotoxicity. LBE liquid spallation target competes with the investigated solid targets in neutronic point of view while has surpass than volatile liquid Hg target.

  10. Investigation of the optimal material type and dimension for spallation targets using simulation methods

    NASA Astrophysics Data System (ADS)

    Feghhi, S. A. H.; Gholamzadeh, Z.; Tenreiro, C.

    2014-03-01

    Accelerator-driven systems are extensively developed to generate neutron sources for research, industrial and medical plans. Different heavy elements are utilized as spallation targets to produce spallation neutrons. Computational methods are efficiently utilized to simulate neutronic behavior of a spallation target. MCNPX 2.6.0 is used as a powerful code based on Monte Carlo stochastic techniques for spallation process computation. This code has the ability to transport different particles using different physical models. In this paper, MCNPX has been utilized to calculate the leaked neutron yield from Pb, LBE, W, Ta, Hg, U, Th, Sn and Cu cylindrical heavy targets. Effects of the target thickness and diameter on neutron yield value have been investigated via the thickness and diameter variations between 5-30 and 5-20 cm, respectively. Proton-induced radionuclide production into the targets as well as leaked neutron spectra from the targets has been calculated for the targets of an optimum determined dimension. 1 GeV proton particle has been selected to induce spallation process inside the targets. 2 mm spatial FWHM distribution has been considered for the 1 mA proton beam. Uranium target produced the highest leaked neutron yield with a 1.32-3.7 factor overweigh the others. Dimension of 15 × 60 cm is suggested for all the cylindrical studied spallation targets. Th target experienced the highest alpha-emitter radionuclide production while lighter elements such as Cu and Sn bore the lowest radio-toxicity. LBE liquid spallation target competes with the investigated solid targets in neutronic point of view while has surpass than volatile liquid Hg target.

  11. Optimized sgRNA design to maximize activity and minimize off-target effects of CRISPR-Cas9

    PubMed Central

    Donovan, Katherine F.; Smith, Ian; Tothova, Zuzana; Wilen, Craig; Orchard, Robert; Virgin, Herbert W.; Root, David E.

    2015-01-01

    CRISPR-Cas9-based genetic screens are a powerful new tool in biology. By simply altering the sequence of the single-guide RNA (sgRNA), Cas9 can be reprogrammed to target different sites in the genome with relative ease, but the on-target activity and off-target effects of individual sgRNAs can vary widely. Here, we use recently-devised sgRNA design rules to create human and mouse genome-wide libraries, perform positive and negative selection screens and observe that the use of these rules produced improved results. Additionally, we profile the off-target activity of thousands of sgRNAs and develop a metric to predict off-target sites. We incorporate these findings from large-scale, empirical data to improve our computational design rules and create optimized sgRNA libraries that maximize on-target activity and minimize off-target effects to enable more effective and efficient genetic screens and genome engineering. PMID:26780180

  12. 7. View showing placement of timber deck placement on chord ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. View showing placement of timber deck placement on chord and built up construction of top chord and continuous construction through top panel points, eye bar construction on bottom chord - Bridge No. 2.4, Spanning Boiling Fork Creek at Railroad Milepost JC-2.4, Decherd, Franklin County, TN

  13. Client-Centered Placement Revisited: A Dialogue on Placement Philosophy

    ERIC Educational Resources Information Center

    Salomone, Paul R.; Usdane, William M.

    1977-01-01

    The authors take substantially different philosophical stances concerning placement in the rehabilitation process. Usdane believes that job placement is not given enough attention by rehabilitation counselors early in the rehabilitation process. Salomone advocates a greater emphasis on client growth and independence. (Author)

  14. Spatial targeting of agri-environmental policy using bilevel evolutionary optimization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this study we describe the optimal designation of agri-environmental policy as a bilevel optimization problem and propose an integrated solution method using a hybrid genetic algorithm. The problem is characterized by a single leader, the agency, that establishes a policy with the goal of optimiz...

  15. Optimization of multifocal transcranial current stimulation for weighted cortical pattern targeting from realistic modeling of electric fields

    PubMed Central

    Ruffini, Giulio; Fox, Michael D.; Ripolles, Oscar; Miranda, Pedro Cavaleiro; Pascual-Leone, Alvaro

    2014-01-01

    Recently, multifocal transcranial current stimulation (tCS) devices using several relatively small electrodes have been used to achieve more focal stimulation of specific cortical targets. However, it is becoming increasingly recognized that many behavioral manifestations of neurological and psychiatric disease are not solely the result of abnormality in one isolated brain region but represent alterations in brain networks. In this paper we describe a method for optimizing the configuration of multifocal tCS for stimulation of brain networks, represented by spatially extended cortical targets. We show how, based on fMRI, PET, EEG or other data specifying a target map on the cortical surface for excitatory, inhibitory or neutral stimulation and a constraint of the maximal number of electrodes, a solution can be produced with the optimal currents and locations of the electrodes. The method described here relies on a fast calculation of multifocal tCS electric fields (including components normal and tangential to the cortical boundaries) using a five layer finite element model of a realistic head. Based on the hypothesis that the effects of current stimulation are to first order due to the interaction of electric fields with populations of elongated cortical neurons, it is argued that the optimization problem for tCS stimulation can be defined in terms of the component of the electric field normal to the cortical surface. Solutions are found using constrained least squares to optimize current intensities, while electrode number and their locations are selected using a genetic algorithm. For direct current tCS (tDCS) applications, we provide some examples of this technique using an available tCS system providing 8 small Ag/AgCl stimulation electrodes. We demonstrate the approach both for localized and spatially extended targets defined using rs-fcMRI and PET data, with clinical applications in stroke and depression. Finally, we extend these ideas to more general

  16. Low-Z target optimization for spatial resolution improvement in megavoltage imaging

    SciTech Connect

    Connell, Tanner; Robar, James L.

    2010-01-15

    Purpose: Recently, several authors have shown contrast improvements in megavoltage portal imaging and cone-beam computed tomography using low atomic number (Z) targets. This work compliments previous studies by investigating the effects of varying different beam production parameters including target atomic number, target thickness, and incident electron energy on spatial resolution. Methods: Target materials of beryllium, aluminum, and tungsten were investigated over a range of thicknesses between 10% and 100% of the continuous slowing down approximation range of electrons. Incident electron kinetic energies of 4.5 and 7.0 MeV were used, in conjunction with custom targets installed above the carousel of a modern radiotherapy linear accelerator. Monte Carlo simulations of the accelerator were constructed and compared to the experimental results. Results: The results showed that thinner targets, as well higher incident electron energies, generally produce more favorable modulation transfer function (MTF) curves. Due to an MTF dependence of the detector system on the photon energy, the experimental results showed that low-Z targets produced superior MTF curves. Simulations showed 14.5% and 21.5% increases in f{sub 50} for the 7.0 and 4.5 MeV targets (Al; 60%R{sub %CSDA}), respectively, when moved from the carousel to the location of the clinical target. f{sub 50} values for the custom targets were compared to the clinical 6 MV beam and were found to be between 10.4% lower (4.5 MeV/W) and 15.5% higher (7.0 MeV/Be). Conclusions: Integration of low-Z external targets into the treatment head of a medical linear was achieved with only minor modifications. It was shown that reasonably high resolution images on par or better than those acquired with the clinical 6 MV beam can be achieved using external low-Z targets.

  17. Virtobot 2.0: the future of automated surface documentation and CT-guided needle placement in forensic medicine.

    PubMed

    Ebert, Lars Christian; Ptacek, Wolfgang; Breitbeck, Robert; Fürst, Martin; Kronreif, Gernot; Martinez, Rosa Maria; Thali, Michael; Flach, Patricia M

    2014-06-01

    In this paper we present the second prototype of a robotic system to be used in forensic medicine. The system is capable of performing automated surface documentation using photogrammetry, optical surface scanning and image-guided, post-mortem needle placement for tissue sampling, liquid sampling, or the placement of guide wires. The upgraded system includes workflow optimizations, an automatic tool-change mechanism, a new software module for trajectory planning and a fully automatic computed tomography-data-set registration algorithm. We tested the placement accuracy of the system by using a needle phantom with radiopaque markers as targets. The system is routinely used for surface documentation and resulted in 24 surface documentations over the course of 11 months. We performed accuracy tests for needle placement using a biopsy phantom, and the Virtobot placed introducer needles with an accuracy of 1.4 mm (±0.9 mm). The second prototype of the Virtobot system is an upgrade of the first prototype but mainly focuses on streamlining the workflow and increasing the level of automation and also has an easier user interface. These upgrades make the Virtobot a potentially valuable tool for case documentation in a scalpel-free setting that uses purely imaging techniques and minimally invasive procedures and is the next step toward the future of virtual autopsy. PMID:24474435

  18. Preparation, Evaluation and Optimization of Multiparticulate System of Mebendazole for Colon Targeted Drug Delivery by Using Natural Polysaccharides

    PubMed Central

    Hemraj Ramteke, Kuldeep; Balaji Jadhav, Varsha; Kulkarni, Nilesh Shrikant; Kharat, Amol Rameshrao; Diwate, Sonali Bhima

    2015-01-01

    Purpose: A Multiparticulate system of Mebendazole was developed for colon targeted drug delivery by using natural polysaccharides like Chitosan and Sodium-alginate beads. Methods: Chitosan microspheres were formulated by using Emulsion crosslinking method using Glutaraldehyde as crosslinking agent. Sodium-alginate beads were formulated by using Calcium chloride as gelling agent. Optimization for Chitosan microspheres was carried out by using 23 full factorial design. 32 full factorial design was used for the optimization of Sodium-alginate beads. The formulated batches were evaluated for percentage yield, particle size measurement, flow properties, percent entrapment efficiency, Swelling studies. The formulations were subjected to Stability studies and In-vitro release study (with and without rat caecal content). Release kinetics data was subjected to different dissolution models. Results: The formulated batches showed acceptable particle size range as well as excellent flow properties. Entrapment efficiency for optimized batches of Chitosan microspheres and sodium alginate beads was found to be 74.18% and 88.48% respectively. In-vitro release of drug for the optimized batches was found to be increased in presence of rat caecal content. The best-fit models were koresmeyer-peppas for Chitosan microspheres and zero order for sodium-alginate beads. Conclusion: Chitosan and Sodium-alginate was used successfully for the formulation of Colon targeted Multiparticulate system. PMID:26504758

  19. The optimization of intensity modulated radiotherapy in cases where the planning target volume extends into the build-up region.

    PubMed

    Nguyen, T B; Hoole, A C F; Burnet, N G; Thomas, S J

    2009-04-21

    A common clinical problem in IMRT, especially when treating head and neck cases, is that the clinical target volume (CTV) stops short of the skin surface, whilst the margin for geometric uncertainties may take the planning target volume (PTV) to the skin surface or beyond. In these cases, optimization leads to over-dosing of the skin, unless the planner resorts to procedural tricks to avoid this, such as the use of pretend bolus or reduction of the PTV followed by adding 'flash' after optimization. This paper describes a method of avoiding the need for these tricks by using a multiple-isocentre CTV-based objective function. This enables plans to be produced that will give good coverage of the CTV for all the geometrical uncertainties that would have been covered by the PTV without causing the problem of over-dosing the skin. Eight isocentre shifts, equally distributed on the surface of a sphere with a radius equal to the CTV-PTV margin, are shown to be adequate for the optimization process. The resulting fluence maps are much simpler than those resulting from PTV optimization and will therefore be simpler to deliver. The method also permits better sparing of organs at risk such as the spinal cord. PMID:19336846

  20. MAPP: A Mathematics Placement Program.

    ERIC Educational Resources Information Center

    Doblin, Stephen A.

    1978-01-01

    MAPP (A Mathematics Placement Program) uses two COBOL programs to place entering freshmen in mathematics courses which are commensurate with their backgrounds and abilities. Having been used for three years, the program is considered to be a viable alternative to the traditional mathematics placement process. (Author/JKS)

  1. Computerized Placement Tests: Background Readings.

    ERIC Educational Resources Information Center

    College Entrance Examination Board, Princeton, NJ.

    This document is a compilation of background readings for the user of Computerized Placement Tests (CPTs) developed by the College Board for student placement purposes. CPTs are computerized adaptive tests that test the individual abilities and backgrounds of examinees. CPTs are part of the ACCUPLACER student information management system. The…

  2. Improvement of Job Placement Services.

    ERIC Educational Resources Information Center

    Mount San Antonio Community Coll. District, Walnut, CA.

    The Improvement of Job Placement Services Project was undertaken to examine and strengthen job placement services and programs in the California community colleges. Specific objectives of the project were to: (1) select and convene a 12-member representative advisory committee to oversee project operations working with the California Placement…

  3. Job Placement Services Research Study.

    ERIC Educational Resources Information Center

    McLeod, Pat N.; Tobias, Jeanette

    A mailout questionnaire was used in a study which focused on three areas of inquiry: (1) Needs assessment for job placement programs in public schools as viewed by superintendents of school districts and vocational administrators of occupational programs, (2) assessment of the perceived and established benefits of a placement program from the…

  4. 30 CFR 57.22004 - Category placement or change in placement.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Category placement or change in placement. 57... placement or change in placement. The Administrator for Metal and Nonmetal Mine Safety and Health (Administrator) shall be responsible for category and subcategory placement, change in placement,...

  5. 30 CFR 57.22004 - Category placement or change in placement.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Category placement or change in placement. 57... placement or change in placement. The Administrator for Metal and Nonmetal Mine Safety and Health (Administrator) shall be responsible for category and subcategory placement, change in placement,...

  6. 30 CFR 57.22004 - Category placement or change in placement.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Category placement or change in placement. 57... placement or change in placement. The Administrator for Metal and Nonmetal Mine Safety and Health (Administrator) shall be responsible for category and subcategory placement, change in placement,...

  7. 30 CFR 57.22004 - Category placement or change in placement.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Category placement or change in placement. 57... placement or change in placement. The Administrator for Metal and Nonmetal Mine Safety and Health (Administrator) shall be responsible for category and subcategory placement, change in placement,...

  8. 30 CFR 57.22004 - Category placement or change in placement.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Category placement or change in placement. 57... placement or change in placement. The Administrator for Metal and Nonmetal Mine Safety and Health (Administrator) shall be responsible for category and subcategory placement, change in placement,...

  9. On Optimizing K-Shell X-ray Conversion Efficiencies with New Nano-structured Laser Targets

    NASA Astrophysics Data System (ADS)

    Colvin, Jeffrey; Charnvanichborikarn, Supakit; Felter, Tom; Flores, Chad; Fournier, Kevin; Gilbert, Dustin; Kucheyev, Sergei; Liu, Kai

    2011-10-01

    We have begun developing new nano-fabrication techniques to make suitable laser targets that can form highly uniform high-Z non-LTE plasmas when illuminated by high-intensity laser light. In this presentation we first discuss progress in developing very low-density pure Cu foams via a four-step ion-lithography process and progress in mechanically trapping Cu nanowires in a silica aerogel foam. We then discuss the radiation-hydrodynamics and non-LTE atomic physics modeling of various targets we could assemble from these foams, and what the modeling reveals about how best to optimize Cu K-shell x-ray conversion efficiencies via target design. This work was performed under the auspices of the U.S. Department of Energy by LLNL under Contract No. DE-AC52-07NA27344, with funding from a Basic Research grant from the U.S. Defense Threat Reduction Agency.

  10. Biological/biomedical accelerator mass spectrometry targets. 1. optimizing the CO2 reduction step using zinc dust.

    PubMed

    Kim, Seung-Hyun; Kelly, Peter B; Clifford, Andrew J

    2008-10-15

    Biological and biomedical applications of accelerator mass spectrometry (AMS) use isotope ratio mass spectrometry to quantify minute amounts of long-lived radioisotopes such as (14)C. AMS target preparation involves first the oxidation of carbon (in sample of interest) to CO 2 and second the reduction of CO 2 to filamentous, fluffy, fuzzy, or firm graphite-like substances that coat a -400-mesh spherical iron powder (-400MSIP) catalyst. Until now, the quality of AMS targets has been variable; consequently, they often failed to produce robust ion currents that are required for reliable, accurate, precise, and high-throughput AMS for biological/biomedical applications. Therefore, we described our optimized method for reduction of CO 2 to high-quality uniform AMS targets whose morphology we visualized using scanning electron microscope pictures. Key features of our optimized method were to reduce CO 2 (from a sample of interest that provided 1 mg of C) using 100 +/- 1.3 mg of Zn dust, 5 +/- 0.4 mg of -400MSIP, and a reduction temperature of 500 degrees C for 3 h. The thermodynamics of our optimized method were more favorable for production of graphite-coated iron powders (GCIP) than those of previous methods. All AMS targets from our optimized method were of 100% GCIP, the graphitization yield exceeded 90%, and delta (13)C was -17.9 +/- 0.3 per thousand. The GCIP reliably produced strong (12)C (-) currents and accurate and precise F m values. The observed F m value for oxalic acid II NIST SRM deviated from its accepted F m value of 1.3407 by only 0.0003 +/- 0.0027 (mean +/- SE, n = 32), limit of detection of (14)C was 0.04 amol, and limit of quantification was 0.07 amol, and a skilled analyst can prepare as many as 270 AMS targets per day. More information on the physical (hardness/color), morphological (SEMs), and structural (FT-IR, Raman, XRD spectra) characteristics of our AMS targets that determine accurate, precise, and high-hroughput AMS measurement are in the

  11. Influence of the illumination source on model-based SRAF placement

    NASA Astrophysics Data System (ADS)

    Gupta, Rachit; Dave, Aasutosh; Tejnil, Edita; Jayaram, Srividya; LaCour, Pat

    2011-04-01

    Sub-Resolution Assist Features (SRAFs) have been extensively used to improve the process margin for isolated and semi-isolated features. It has been shown that compared to rule-based SRAFs, model-based placement of SRAFs can result in better overall process window. Various model-based approaches have been reported to affect SRAF placements. Even with model-based solutions, the complexity of two-dimensional layouts results in SRAF placement conflicts, producing numerous challenges to optimal SRAF placement for each pattern configuration. Furthermore, tuning of SRAF placement algorithms becomes challenging with varying patterns and sources [1-3]. Recently, pixelated source in optical lithography has become the subject of increased exploration to enable 22/20 nm technology nodes and beyond. Optimization of the illumination shape, including free-form pixelated sources, has shown performance gains, compared to standard source shapes [4-6]. This paper will demonstrate the influence of such different free-form sources as well as conventional sources on model-based SRAF placement. Typically in source optimization, the selection of the optimization patterns is exigent since it drives the source solution. Small differences in the selected patterns produce subtle changes in the optimized source shapes. It has also been previously reported that SRAF placements are significantly dependent on the illumination [1]. In this paper, the impact of changes in the design and/or source optimization patterns on the optimized source and hence on the SRAF placement is reported. Variations in SRAF placements will be quantified as a function of change in the free-form sources. Lithographic performance of the different SRAF placement schema will be verified using simulation.

  12. A simple optimization approach for improving target dose homogeneity in intensity-modulated radiotherapy for sinonasal cancer

    PubMed Central

    Lu, Jia-Yang; Zhang, Ji-Yong; Li, Mei; Cheung, Michael Lok-Man; Li, Yang-Kang; Zheng, Jing; Huang, Bao-Tian; Zhang, Wu-Zhe

    2015-01-01

    Homogeneous target dose distribution in intensity-modulated radiotherapy (IMRT) for sinonasal cancer (SNC) is challenging to achieve. To solve this problem, we established and evaluated a basal-dose-compensation (BDC) optimization approach, in which the treatment plan is further optimized based on the initial plans. Generally acceptable initial IMRT plans for thirteen patients were created and further optimized individually by (1) the BDC approach and (2) a local-dose-control (LDC) approach, in which the initial plan is further optimized by addressing hot and cold spots. We compared the plan qualities, total planning time and monitor units (MUs) among the initial, BDC, LDC IMRT plans and volumetric modulated arc therapy (VMAT) plans. The BDC approach provided significantly superior dose homogeneity/conformity by 23%–48%/6%–9% compared with both the initial and LDC IMRT plans, as well as reduced doses to the organs at risk (OARs) by up to 18%, with acceptable MU numbers. Compared with VMAT, BDC IMRT yielded superior homogeneity, inferior conformity and comparable overall OAR sparing. The planning of BDC, LDC IMRT and VMAT required 30, 59 and 58 minutes on average, respectively. Our results indicated that the BDC optimization approach can achieve significantly better dose distributions with shorter planning time in the IMRT for SNC. PMID:26497620

  13. Placement of the acetabular component.

    PubMed

    Beverland, D E; O'Neill, C K J; Rutherford, M; Molloy, D; Hill, J C

    2016-01-01

    Ideal placement of the acetabular component remains elusive both in terms of defining and achieving a target. Our aim is to help restore original anatomy by using the transverse acetabular ligament (TAL) to control the height, depth and version of the component. In the normal hip the TAL and labrum extend beyond the equator of the femoral head and therefore, if the definitive acetabular component is positioned such that it is cradled by and just deep to the plane of the TAL and labrum and is no more than 4mm larger than the original femoral head, the centre of the hip should be restored. If the face of the component is positioned parallel to the TAL and psoas groove the patient specific version should be restored. We still use the TAL for controlling version in the dysplastic hip because we believe that the TAL and labrum compensate for any underlying bony abnormality. The TAL should not be used as an aid to inclination. Worldwide, > 75% of surgeons operate with the patient in the lateral decubitus position and we have shown that errors in post-operative radiographic inclination (RI) of > 50° are generally caused by errors in patient positioning. Consequently, great care needs to be taken when positioning the patient. We also recommend 35° of apparent operative inclination (AOI) during surgery, as opposed to the traditional 45°. PMID:26733639

  14. A model-based reasoning approach to sensor placement for monitorability

    NASA Technical Reports Server (NTRS)

    Chien, Steve; Doyle, Richard; Homemdemello, Luiz

    1992-01-01

    An approach is presented to evaluating sensor placements to maximize monitorability of the target system while minimizing the number of sensors. The approach uses a model of the monitored system to score potential sensor placements on the basis of four monitorability criteria. The scores can then be analyzed to produce a recommended sensor set. An example from our NASA application domain is used to illustrate our model-based approach to sensor placement.

  15. Optimal Strategies for Controlling Riverine Tsetse Flies Using Targets: A Modelling Study

    PubMed Central

    Vale, Glyn A.; Hargrove, John W.; Lehane, Michael J.; Solano, Philippe; Torr, Stephen J.

    2015-01-01

    Background Tsetse flies occur in much of sub-Saharan Africa where they transmit the trypanosomes that cause the diseases of sleeping sickness in humans and nagana in livestock. One of the most economical and effective methods of tsetse control is the use of insecticide-treated screens, called targets, that simulate hosts. Targets have been ~1m2, but recently it was shown that those tsetse that occupy riverine situations, and which are the main vectors of sleeping sickness, respond well to targets only ~0.06m2. The cheapness of these tiny targets suggests the need to reconsider what intensity and duration of target deployments comprise the most cost-effective strategy in various riverine habitats. Methodology/Principal Findings A deterministic model, written in Excel spreadsheets and managed by Visual Basic for Applications, simulated the births, deaths and movement of tsetse confined to a strip of riverine vegetation composed of segments of habitat in which the tsetse population was either self-sustaining, or not sustainable unless supplemented by immigrants. Results suggested that in many situations the use of tiny targets at high density for just a few months per year would be the most cost-effective strategy for rapidly reducing tsetse densities by the ~90% expected to have a great impact on the incidence of sleeping sickness. Local elimination of tsetse becomes feasible when targets are deployed in isolated situations, or where the only invasion occurs from populations that are not self-sustaining. Conclusion/Significance Seasonal use of tiny targets deserves field trials. The ability to recognise habitat that contains tsetse populations which are not self-sustaining could improve the planning of all methods of tsetse control, against any species, in riverine, savannah or forest situations. Criteria to assist such recognition are suggested. PMID:25803871

  16. Impact of uncertain head tissue conductivity in the optimization of transcranial direct current stimulation for an auditory target

    NASA Astrophysics Data System (ADS)

    Schmidt, Christian; Wagner, Sven; Burger, Martin; van Rienen, Ursula; Wolters, Carsten H.

    2015-08-01

    Objective. Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique to modify neural excitability. Using multi-array tDCS, we investigate the influence of inter-individually varying head tissue conductivity profiles on optimal electrode configurations for an auditory cortex stimulation. Approach. In order to quantify the uncertainty of the optimal electrode configurations, multi-variate generalized polynomial chaos expansions of the model solutions are used based on uncertain conductivity profiles of the compartments skin, skull, gray matter, and white matter. Stochastic measures, probability density functions, and sensitivity of the quantities of interest are investigated for each electrode and the current density at the target with the resulting stimulation protocols visualized on the head surface. Main results. We demonstrate that the optimized stimulation protocols are only comprised of a few active electrodes, with tolerable deviations in the stimulation amplitude of the anode. However, large deviations in the order of the uncertainty in the conductivity profiles could be noted in the stimulation protocol of the compensating cathodes. Regarding these main stimulation electrodes, the stimulation protocol was most sensitive to uncertainty in skull conductivity. Finally, the probability that the current density amplitude in the auditory cortex target region is supra-threshold was below 50%. Significance. The results suggest that an uncertain conductivity profile in computational models of tDCS can have a substantial influence on the prediction of optimal stimulation protocols for stimulation of the auditory cortex. The investigations carried out in this study present a possibility to predict the probability of providing a therapeutic effect with an optimized electrode system for future auditory clinical and experimental procedures of tDCS applications.

  17. Optimization of Spin-Polarization of Helium-3 Target Cell by Thermal Convection Processes

    NASA Astrophysics Data System (ADS)

    Karthas, Stacy

    2013-10-01

    Polarized Helium-3 (3He) is an effective polarized neutron target that has been used in particle accelerators like the Thomas Jefferson National Accelerator Facility (TJNAF) for the past three decades to study properties of the neutron. Due to the spin structure of its nucleons, the nucleus of 3He can be approximated as a single polarized neutron. The previous generations of 3He targets have reached their limit in polarization and are not ideal for use as targets with the 12 GeV update at TJNAF due to large polarization gradients. The new target cell uses thermal convection to transfer polarized gas to the target chamber quickly. The focus of this project was to study the effects of the new convection system, at various gas velocities, on Adiabatic Fast Passage (AFP) polarization loss that results from measuring the polarization of 3He with Nuclear Magnetic Resonance (NMR). Gas velocities were varied by using a Kapton flexible heater to induce thermal convection. This target cell loses less than one percent of its polarization by measurement when convection is induced at a gas velocity under 6 cm/min thereby verifying the possible use of convection induction for the future experiments. Research conducted at Thomas Jefferson National Accelerator Facility funded through a grant from NSF by the Old Dominion University Research Experience for Undergraduates Program.

  18. An auto-adaptive optimization approach for targeting nonpoint source pollution control practices

    NASA Astrophysics Data System (ADS)

    Chen, Lei; Wei, Guoyuan; Shen, Zhenyao

    2015-10-01

    To solve computationally intensive and technically complex control of nonpoint source pollution, the traditional genetic algorithm was modified into an auto-adaptive pattern, and a new framework was proposed by integrating this new algorithm with a watershed model and an economic module. Although conceptually simple and comprehensive, the proposed algorithm would search automatically for those Pareto-optimality solutions without a complex calibration of optimization parameters. The model was applied in a case study in a typical watershed of the Three Gorges Reservoir area, China. The results indicated that the evolutionary process of optimization was improved due to the incorporation of auto-adaptive parameters. In addition, the proposed algorithm outperformed the state-of-the-art existing algorithms in terms of convergence ability and computational efficiency. At the same cost level, solutions with greater pollutant reductions could be identified. From a scientific viewpoint, the proposed algorithm could be extended to other watersheds to provide cost-effective configurations of BMPs.

  19. Target-specific optimization of four-dimensional cone beam computed tomography

    SciTech Connect

    Ahmad, Moiz; Pan Tinsu

    2012-09-15

    Purpose: Under-sampling artifacts are a major problem in four-dimensional cone-beam computed tomography (4D-CBCT) and may compromise evaluation of target motion. Several studies have addressed scan parameter selection for minimizing under-sampling artifacts; however, the role of the target characteristics in scan parameter selection has not been investigated. In this work, the authors evaluated 4D-CBCT performance by assessing the accuracy of target motion measurements for various target sizes and motions. The results may serve as patient-specific guidelines for scan parameters selection in 4D-CBCT. Methods: The authors acquired 4D-CBCT scans of a moving phantom consisting of six water-filled sphere targets of sizes 10-37 mm, using various scan times ranging from 30 s to 3 min., setting the motion to 3-s and 6-s periods. The authors used automatic image registration to extract the target motion trajectories and evaluated these measurements for various target sizes and motions over various combinations of scan parameters including scan time, detector configuration, number of respiration phases, and reconstruction filters. Results: The most important object parameter to 4D-CBCT performance was the period of motion. Measurements for the 6-s motion were always systematically less accurate than measurements for the 3-s motion for 34 of 36 objects of various sizes and periods of motion. The 6-s motion required a greater scan time than the 3-s motion for equivalent measurement accuracy. The second most influential parameter was the target size. For the 3-s period of motion, objects larger than 13 mm were tracked with sub-millimeter accuracy with a 1-min scan time. For the 6-s period of motion, objects larger than 22-mm were tracked with sub-millimeter accuracy with a 1.5-min scan time. For all sizes and motions, temporal blurring was observed when the number of phases was fewer than 8. Offset detector configuration provided the same performance as centered detector except

  20. The Optimal Conditions for Form-Focused Instruction: Method, Target Complexity, and Types of Knowledge

    ERIC Educational Resources Information Center

    Kim, Jeong-eun

    2012-01-01

    This dissertation investigates optimal conditions for form-focused instruction (FFI) by considering effects of internal (i.e., timing and types of FFI) and external (i.e., complexity and familiarity) variables of FFI when it is offered within a primarily meaning-focused context of adult second language (L2) learning. Ninety-two Korean-speaking…

  1. Distance-to-Agreement Investigation of Tomotherapy's Bony Anatomy-Based Autoregistration and Planning Target Volume Contour-Based Optimization

    SciTech Connect

    Suh, Steve; Schultheiss, Timothy E.

    2013-03-01

    Purpose: To compare Tomotherapy's megavoltage computed tomography bony anatomy autoregistration with the best achievable registration, assuming no deformation and perfect knowledge of planning target volume (PTV) location. Methods and Materials: Distance-to-agreement (DTA) of the PTV was determined by applying a rigid-body shift to the PTV region of interest of the prostate from its reference position, assuming no deformations. Planning target volume region of interest of the prostate was extracted from the patient archives. The reference position was set by the 6 degrees of freedom (dof)—x, y, z, roll, pitch, and yaw—optimization results from the previous study at this institution. The DTA and the compensating parameters were calculated by the shift of the PTV from the reference 6-dof to the 4-dof—x, y, z, and roll—optimization. In this study, the effectiveness of Tomotherapy's 4-dof bony anatomy–based autoregistration was compared with the idealized 4-dof PTV contour-based optimization. Results: The maximum DTA (maxDTA) of the bony anatomy-based autoregistration was 3.2 ± 1.9 mm, with the maximum value of 8.0 mm. The maxDTA of the contour-based optimization was 1.8 ± 1.3 mm, with the maximum value of 5.7 mm. Comparison of Pearson correlation of the compensating parameters between the 2 4-dof optimization algorithms shows that there is a small but statistically significant correlation in y and z (0.236 and 0.300, respectively), whereas there is very weak correlation in x and roll (0.062 and 0.025, respectively). Conclusions: We find that there is an average improvement of approximately 1 mm in terms of maxDTA on the PTV going from 4-dof bony anatomy-based autoregistration to the 4-dof contour-based optimization. Pearson correlation analysis of the 2 4-dof optimizations suggests that uncertainties due to deformation and inadequate resolution account for much of the compensating parameters, but pitch variation also makes a statistically significant

  2. Numerical optimization of targeted delivery of charged nanoparticles to the ostiomeatal complex for treatment of rhinosinusitis

    PubMed Central

    Xi, Jinxiang; Yuan, Jiayao Eddie; Si, Xiuhua April; Hasbany, James

    2015-01-01

    Background Despite the prevalence of rhinosinusitis that affects 10%–15% of the population, current inhalation therapy shows limited efficacy. Standard devices deliver <5% of the drugs to the sinuses due to the complexity of nose structure, secluded location of the sinus, poor ventilation, and lack of control of particle motions inside the nasal cavity. Methods An electric-guided delivery system was developed to guide charged particles to the ostiomeatal complex (OMC). Its performance was numerically assessed in an MRI-based nose–sinus model. Key design variables related to the delivery device, drug particles, and patient breathing were determined using sensitivity analysis. A two-stage optimization of design variables was conducted to obtain the best performance of the delivery system using the Nelder-Mead algorithm. Results and discussion The OMC delivery system exhibited high sensitivity to the applied electric field and electrostatic charges carried by the particles. Through the synthesis of electric guidance and point drug release, the new delivery system eliminated particle deposition in the nasal valve and turbinate regions and significantly enhanced the OMC doses. An OMC delivery efficiency of 72.4% was obtained with the optimized design, which is one order of magnitude higher than the standard nasal devices. Moreover, optimization is imperative to achieve a sound delivery protocol because of the large number of design variables. The OMC dose increased from 45.0% in the baseline model to 72.4% in the optimized system. The optimization framework developed in this study can be easily adapted for the delivery of drugs to other sites in the nose such as the ethmoid sinus and olfactory region. PMID:26257521

  3. Optimization of the muon stopping target for the MU2E collaboration

    SciTech Connect

    Hodge, Zachary Donovan

    2013-01-01

    The Mu2e Experiment utilizes state of the art accelerators, superconducting magnets, detectors, electronics, and other equipment to maximize the sensitivity to such a rare process. Many of the components of the Mu2e hardware are critical to the overall physics capability of the experiment. The muon stopping target, where muons are stopped and may interact via this very rare process, is one such component where any improvements beyond the base design can have a significant impact on the experiment. This thesis explores possible modifications to the geometry of the muon stopping target. The goal is to determine if any modifications can improve the sensitivity of observing the muon conversion process.

  4. The role of chemotherapy in managing chronic lymphocytic leukemia: optimizing combinations with targeted therapy.

    PubMed

    Nastoupil, Loretta J; Sinha, Rajni; Flowers, Christopher R

    2013-09-01

    For many years, alkylating agents were the standard treatment for chronic lymphocytic leukemia (CLL). The advent of purine analogs improved response rates, but not overall survival, and although the monoclonal antibody rituximab is generally active against B-cell malignancies, it has demonstrated limited benefits as monotherapy for the treatment of CLL. However, specific combinations of chemotherapy, antibodies and targeted therapies have demonstrated additive or synergistic activity in CLL cells and deliver substantial clinical benefits. A greater understanding of the actions of chemotherapies and targeted agents on cellular pathways will advance the development of rationally designed combinations corresponding to individual patients' disease profiles. PMID:23919536

  5. Finding the optimal statistical model to describe target motion during radiotherapy delivery—a Bayesian approach

    NASA Astrophysics Data System (ADS)

    Herschtal, A.; Foroudi, F.; Greer, P. B.; Eade, T. N.; Hindson, B. R.; Kron, T.

    2012-05-01

    Early approaches to characterizing errors in target displacement during a fractionated course of radiotherapy assumed that the underlying fraction-to-fraction variability in target displacement, known as the ‘treatment error’ or ‘random error’, could be regarded as constant across patients. More recent approaches have modelled target displacement allowing for differences in random error between patients. However, until recently it has not been feasible to compare the goodness of fit of alternate models of random error rigorously. This is because the large volumes of real patient data necessary to distinguish between alternative models have only very recently become available. This work uses real-world displacement data collected from 365 patients undergoing radical radiotherapy for prostate cancer to compare five candidate models for target displacement. The simplest model assumes constant random errors across patients, while other models allow for random errors that vary according to one of several candidate distributions. Bayesian statistics and Markov Chain Monte Carlo simulation of the model parameters are used to compare model goodness of fit. We conclude that modelling the random error as inverse gamma distributed provides a clearly superior fit over all alternatives considered. This finding can facilitate more accurate margin recipes and correction strategies.

  6. Optimizing outcome in SLE: treating-to-target and definition of treatment goals.

    PubMed

    Doria, Andrea; Gatto, Mariele; Zen, Margherita; Iaccarino, Luca; Punzi, Leonardo

    2014-07-01

    Patients affected with systemic lupus erythematosus (SLE) display poor-long term prognosis and increased mortality in respect of general population. This may be due to continuous organ damage accrual which is fostered both by persistent disease activity (mainly in the short term) and prolonged corticosteroid exposure (mainly in the long term). The effort of defining novel therapeutic goals to which patients should be treated in order to have their prognosis improved is named treat-to-target. Remission in SLE was shown to be associated with better outcome and prolonged survival; in clinical practice, patients may experience either complete or clinical remission, which are defined as complete clinical/serological healing or no clinical signs of lupus with active serology, respectively. The main treat-to-target in SLE is complete remission, however since longitudinal observations suggest that clinical remission or low disease activity even with minimal corticosteroid intake do improve patients prognosis and survival as well, they may be assumed as acceptable alternative targets. Suitable therapeutic strategies have to be defined in order for these goals to be achieved including early diagnosis, effective treatment and proper corticosteroid tapering which in turn require development of more reliable serum biomarkers for early disease detection and less toxic targeted therapies with a steroid-sparing potential. PMID:24480071

  7. Optimization of deposition rate in HiPIMS by controlling the peak target current

    NASA Astrophysics Data System (ADS)

    Tiron, V.; Velicu, I.-L.; Vasilovici, O.; Popa, G.

    2015-12-01

    High power impulse magnetron sputtering (HiPIMS) is a very attractive ionized physical vapour deposition technique which has been of great interest over the last decade. Thanks to the high ionization degree of the sputtered material (typically  >50%), this technique is used mainly for enhancing and tailoring coating properties. However, the lower deposition rate compared to the conventional direct-current (dc) magnetron sputtering process still represents a major drawback of HiPIMS. In this contribution, a study of the ability to control the peak target current in HiPIMS discharge through certain experimental parameters and, thus, to overcome the deposition rate limitation is presented. The HiPIMS was operated with ultra-short pulse durations (<20 μs) and two different operation modes have been used: single-pulse mode and multi-pulse mode, respectively. The peak target current was controlled by changing the target voltage, pulse duration, magnetic field, and target erosion depth. For a certain favorable combination of experimental parameters, it was found that the deposition rate value can be increased by a factor of up to 3.5, reaching values only 20% lower than those found in dc.

  8. Optimal blood pressure targets in 2014 - Does the guideline recommendation match the evidence base?

    PubMed

    Alviar, C L; Bangalore, S; Messerli, F H

    2015-01-01

    Various scientific societies have recently published practice guidelines for the diagnosis and management of arterial hypertension with no clear consensus on a blood pressure target. This article reviews those recommendations and critically examines if they are based on sound evidence. PMID:26179968

  9. Optimization of RNA interference (RNAi) targeting acetylcholinesterase in the Southern cattle tick (Rhipicephalus microplus)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Acetylcholinesterase (AChE) is the primary target for organophosphate (OP) acaricides. OP resistant strains of the Southern cattle tick Rhipicephalus microplus have been identified and represent a major threat to the control of this important disease vector. R. microplus ticks possess at least three...

  10. Efficient AID targeting of switch regions is not sufficient for optimal class switch recombination.

    PubMed

    Bonaud, Amélie; Lechouane, Fabien; Le Noir, Sandrine; Monestier, Olivier; Cogné, Michel; Sirac, Christophe

    2015-01-01

    Antibody affinity maturation relies on activation-induced cytidine deaminase (AID)-dependent somatic hypermutation (SHM) of immunoglobulin (Ig) loci. Class switch recombination (CSR) can in parallel occur between AID-targeted, transcribed, spliced and repetitive switch (S) regions. AID thus initiates not only mutations but also double-strand breaks (DSBs). What governs the choice between those two outcomes remains uncertain. Here we explore whether insertion of transcribed intronic S regions in a locus (Igκ) strongly recruiting AID is sufficient for efficient CSR. Although strongly targeted by AID and carrying internal deletions, the knocked-in S regions only undergo rare CSR-like events. This model confirms S regions as exquisite SHM targets, extending AID activity far from transcription initiation sites, and shows that such spliced and repetitive AID targets are not sufficient by themselves for CSR. Beyond transcription and AID recruitment, additional IgH elements are thus needed for CSR, restricting this hazardous gene remodelling to IgH loci. PMID:26146363

  11. Optimization of x-ray emission from under-critical CH foam coated gold targets by laser irradiation

    NASA Astrophysics Data System (ADS)

    Shang, Wanli; Yu, Ruizhen; Zhang, Wenhai; Yang, Jiamin

    2016-08-01

    Under-critical CH foam coated gold targets benefit laser-to-x-ray emission because CH plasma inhibits gold plasma expansion, which leads to higher gold plasma density and temperature. Conversely, the CH foam partially absorbs the incident laser energy, which lowers laser absorption into the gold plasma. An analytical model is built to solve the laser collisional deposition fraction in the CH foam layer. The optimization of x-ray emission from under-critical CH foam coated gold targets by laser irradiation is obtained numerically with different CH foam densities and thicknesses. The plasma and x-ray emission properties are investigated. It is found that different CH thicknesses lead to different increase mechanisms for x-ray emission. The x-ray spectrum distributions show that most of the x-ray emission increases occur with photon energy less than 2000 eV.

  12. Phospholipid-Based Prodrugs for Drug Targeting in Inflammatory Bowel Disease: Computational Optimization and In-Vitro Correlation.

    PubMed

    Dahan, Arik; Ben-Shabat, Shimon; Cohen, Noa; Keinan, Shahar; Kurnikov, Igor; Aponick, Aaron; Zimmermann, Ellen M

    2016-01-01

    In inflammatory bowel disease (IBD) patients, the enzyme phospholipase A2 (PLA2) is overexpressed in the inflamed intestinal tissue, and hence may be exploited as a prodrug-activating enzyme allowing drug targeting to the site(s) of gut inflammation. The purpose of this work was to develop powerful modern computational approaches, to allow optimized a-priori design of phospholipid (PL) based prodrugs for IBD drug targeting. We performed simulations that predict the activation of PL-drug conjugates by PLA2 with both human and bee venom PLA2. The calculated results correlated well with in-vitro experimental data. In conclusion, a-priori drug design using a computational approach complements and extends experimentally derived data, and may improve resource utilization and speed drug development. PMID:27086789

  13. An Optimized GD2-Targeting Retroviral Cassette for More Potent and Safer Cellular Therapy of Neuroblastoma and Other Cancers

    PubMed Central

    Thomas, Simon; Straathof, Karin; Himoudi, Nourredine; Anderson, John; Pule, Martin

    2016-01-01

    Neuroblastoma is the commonest extra cranial solid cancer of childhood. Despite escalation of treatment regimens, a significant minority of patients die of their disease. Disialoganglioside (GD2) is consistently expressed at high-levels in neuroblastoma tumors, which have been targeted with some success using therapeutic monoclonal antibodies. GD2 is also expressed in a range of other cancer but with the exception of some peripheral nerves is largely absent from non-transformed tissues. Chimeric Antigen Receptors (CARs) are artificial type I proteins which graft the specificity of a monoclonal antibody onto a T-cell. Clinical data with early CAR designs directed against GD2 have shown some promise in Neuroblastoma. Here, we describe a GD2-targeting CAR retroviral cassette, which has been optimized for CAR T-cell persistence, efficacy and safety. PMID:27030986

  14. A New Optimal Guidance Law for Air-to-Air Missiles against Evasive Targets

    NASA Astrophysics Data System (ADS)

    Tsao, Lu-Ping; Lin, Ching-Show

    A new optimal guidance law (OPG) for air-to-air missiles, based on the design concept of decreasing the acceleration requirement commanded in the final phase of engagement, is presented. The closed-form solution of the OPG is derived analytically from the time-varying linear state equations composed of the line-of-sight angle and line-of-sight rate. The optimal proportional navigation law and augmented proportional navigation law, where both the navigation constants are 3, have been proven to be simplified versions of the OPG. The performance of the OPG is evaluated and compared with that of the true proportional navigation law (TPN) and augmented proportional navigation law (APN) in terms of the miss distance, interception time and energy expenditure.

  15. Combining Cooperative Education and Placement.

    ERIC Educational Resources Information Center

    Lentz, Glenda F.

    1984-01-01

    Suggests that placement, like cooperative education, can function better in academic affairs rather than student affairs. Describes the combination of the two departments at the University of South Florida and discusses advantages and disadvantages of a combined program. (JAC)

  16. A computational strategy to select optimized protein targets for drug development toward the control of cancer diseases.

    PubMed

    Carels, Nicolas; Tilli, Tatiana; Tuszynski, Jack A

    2015-01-01

    In this report, we describe a strategy for the optimized selection of protein targets suitable for drug development against neoplastic diseases taking the particular case of breast cancer as an example. We combined human interactome and transcriptome data from malignant and control cell lines because highly connected proteins that are up-regulated in malignant cell lines are expected to be suitable protein targets for chemotherapy with a lower rate of undesirable side effects. We normalized transcriptome data and applied a statistic treatment to objectively extract the sub-networks of down- and up-regulated genes whose proteins effectively interact. We chose the most connected ones that act as protein hubs, most being in the signaling network. We show that the protein targets effectively identified by the combination of protein connectivity and differential expression are known as suitable targets for the successful chemotherapy of breast cancer. Interestingly, we found additional proteins, not generally targeted by drug treatments, which might justify the extension of existing formulation by addition of inhibitors designed against these proteins with the consequence of improving therapeutic outcomes. The molecular alterations observed in breast cancer cell lines represent either driver events and/or driver pathways that are necessary for breast cancer development or progression. However, it is clear that signaling mechanisms of the luminal A, B and triple negative subtypes are different. Furthermore, the up- and down-regulated networks predicted subtype-specific drug targets and possible compensation circuits between up- and down-regulated genes. We believe these results may have significant clinical implications in the personalized treatment of cancer patients allowing an objective approach to the recycling of the arsenal of available drugs to the specific case of each breast cancer given their distinct qualitative and quantitative molecular traits. PMID:25625699

  17. A Computational Strategy to Select Optimized Protein Targets for Drug Development toward the Control of Cancer Diseases

    PubMed Central

    Carels, Nicolas; Tilli, Tatiana; Tuszynski, Jack A.

    2015-01-01

    In this report, we describe a strategy for the optimized selection of protein targets suitable for drug development against neoplastic diseases taking the particular case of breast cancer as an example. We combined human interactome and transcriptome data from malignant and control cell lines because highly connected proteins that are up-regulated in malignant cell lines are expected to be suitable protein targets for chemotherapy with a lower rate of undesirable side effects. We normalized transcriptome data and applied a statistic treatment to objectively extract the sub-networks of down- and up-regulated genes whose proteins effectively interact. We chose the most connected ones that act as protein hubs, most being in the signaling network. We show that the protein targets effectively identified by the combination of protein connectivity and differential expression are known as suitable targets for the successful chemotherapy of breast cancer. Interestingly, we found additional proteins, not generally targeted by drug treatments, which might justify the extension of existing formulation by addition of inhibitors designed against these proteins with the consequence of improving therapeutic outcomes. The molecular alterations observed in breast cancer cell lines represent either driver events and/or driver pathways that are necessary for breast cancer development or progression. However, it is clear that signaling mechanisms of the luminal A, B and triple negative subtypes are different. Furthermore, the up- and down-regulated networks predicted subtype-specific drug targets and possible compensation circuits between up- and down-regulated genes. We believe these results may have significant clinical implications in the personalized treatment of cancer patients allowing an objective approach to the recycling of the arsenal of available drugs to the specific case of each breast cancer given their distinct qualitative and quantitative molecular traits. PMID:25625699

  18. Optimized dynamic contrast-enhanced cone-beam CT for target visualization during liver SBRT

    NASA Astrophysics Data System (ADS)

    Jones, Bernard L.; Altunbas, Cem; Kavanagh, Brian; Schefter, Tracey; Miften, Moyed

    2014-03-01

    The pharmacokinetic behavior of iodine contrast agents makes it difficult to achieve significant enhancement during contrast-enhanced cone-beam CT (CE-CBCT). This study modeled this dynamic behavior to optimize CE-CBCT and improve the localization of liver lesions for SBRT. We developed a model that allows for controlled study of changing iodine concentrations using static phantoms. A projection database consisting of multiple phantom images of differing iodine/scan conditions was built. To reconstruct images of dynamic hepatic concentrations, hepatic contrast enhancement data from conventional CT scans were used to re-assemble the projections to match the expected amount of contrast. In this way the effect of various parameters on image quality was isolated, and using our dynamic model we found parameters for iodine injection, CBCT scanning, and injection/scanning timing which optimize contrast enhancement. Increasing the iodine dose, iodine injection rate, and imaging dose led to significant increases in signal-to-noise ratio (SNR). Reducing the CBCT imaging time also increased SNR, as the image can be completed before the iodine exits the liver. Proper timing of image acquisition played a significant role, as a 30 second error in start time resulted in a 40% SNR decrease. The effect of IV contrast is severely degraded in CBCT, but there is promise that, with optimization of the injection and scan parameters to account for iodine pharmacokinetics, CE-CBCT which models venous-phase blood flow kinetics will be feasible for accurate localization of liver lesions.

  19. An auto-adaptive optimization approach for targeting nonpoint source pollution control practices

    PubMed Central

    Chen, Lei; Wei, Guoyuan; Shen, Zhenyao

    2015-01-01

    To solve computationally intensive and technically complex control of nonpoint source pollution, the traditional genetic algorithm was modified into an auto-adaptive pattern, and a new framework was proposed by integrating this new algorithm with a watershed model and an economic module. Although conceptually simple and comprehensive, the proposed algorithm would search automatically for those Pareto-optimality solutions without a complex calibration of optimization parameters. The model was applied in a case study in a typical watershed of the Three Gorges Reservoir area, China. The results indicated that the evolutionary process of optimization was improved due to the incorporation of auto-adaptive parameters. In addition, the proposed algorithm outperformed the state-of-the-art existing algorithms in terms of convergence ability and computational efficiency. At the same cost level, solutions with greater pollutant reductions could be identified. From a scientific viewpoint, the proposed algorithm could be extended to other watersheds to provide cost-effective configurations of BMPs. PMID:26487474

  20. Novel lead compound optimization and synthesized based on the target structure of Xanthomonas oryzae pv. oryzae GlmU.

    PubMed

    Qi, Xiaojuan; Deng, Wenjun; Gao, Min; Mao, Bangqiang; Xu, Shengzhen; Chen, Changshui; Zhang, Qingye

    2015-07-01

    Bacterial leaf blight, caused by Xanthomonas oryzae pv. oryzae, is one of the most destructive diseases of rice worldwide. N-acetylglucosamine-1-phosphate uridyltransferase (GlmU) was an attractive target for the development of antimicrobial agents. To develop novel, more potent and even more selective inhibitors of the uridyltransferase activity of Xanthomonas oryzae pv. oryzae GlmU (Xo-GlmU), three types of novel target compounds were optimized and synthesized based on the Xo-GlmU structure in this study. The biological testing results showed that all of the target compounds displayed the higher inhibition than the lead compound with the IC50 values in the 10.82-23.31 µM range, and the inhibition rates were increased by 30%-67%. The binding mode and the possible inhibitory mechanism of the target compounds in the active site were also analyzed by the molecular docking based on the uridyltransferase active site of Xo-GlmU. PMID:26071803

  1. Life-Skills Knowledge: A Survey of Foster Adolescents in Three Placement Settings.

    ERIC Educational Resources Information Center

    Mech, Edmund V.; And Others

    1994-01-01

    Assessed life-skills knowledge levels among older foster adolescents in foster family homes, group homes/institutions, and apartments. Results suggest a need to improve life-skills preparation in group home/institutional settings, to target minority males for life-skills enhancement in all placement settings, and to utilize apartment placements to…

  2. 34 CFR 300.327 - Educational placements.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 34 Education 2 2011-07-01 2010-07-01 true Educational placements. 300.327 Section 300.327... Educational Placements Development of Iep § 300.327 Educational placements. Consistent with § 300.501(c), each... makes decisions on the educational placement of their child. (Authority: 20 U.S.C. 1414(e))...

  3. Optimization of Adaboost Algorithm for Sonar Target Detection in a Multi-Stage ATR System

    NASA Technical Reports Server (NTRS)

    Lin, Tsung Han (Hank)

    2011-01-01

    JPL has developed a multi-stage Automated Target Recognition (ATR) system to locate objects in images. First, input images are preprocessed and sent to a Grayscale Optical Correlator (GOC) filter to identify possible regions-of-interest (ROIs). Second, feature extraction operations are performed using Texton filters and Principal Component Analysis (PCA). Finally, the features are fed to a classifier, to identify ROIs that contain the targets. Previous work used the Feed-forward Back-propagation Neural Network for classification. In this project we investigate a version of Adaboost as a classifier for comparison. The version we used is known as GentleBoost. We used the boosted decision tree as the weak classifier. We have tested our ATR system against real-world sonar images using the Adaboost approach. Results indicate an improvement in performance over a single Neural Network design.

  4. CFD analysis and optimization of a liquid lead-bismuth loop target for ISOL facilities

    NASA Astrophysics Data System (ADS)

    Houngbo, D.; Popescu, L.; Schuurmans, P.; Delonca, M.; Losito, R.; Maglioni, C.; Stora, T.; Bricault, P.; Vierendeels, J.

    2015-03-01

    In the context of the forthcoming next generation of Radioactive Ion Beams (RIBs) facilities based on an Isotope Separation On Line (ISOL) method, the development of production targets capable of dissipating the high power deposited by the primary beam is a major challenge. The concept of a high-power target based on a liquid Pb-Bi loop incorporating a heat-exchanger and a diffusion chamber was proposed within EURISOL DS and is being developed within the LIEBE1 This study shows that approximately 100 ms after the proton pulse the irradiated liquid-metal is entirely and uniformly evacuated from the irradiation volume and spread in a shower of small droplets (100-μm radii), in order to reduce the diffusion length of isotopes. Solutions to deal with the typical cavitation risk due to the presence of low-pressure zones in the liquid have also been found and simulated.

  5. Optimized planning target volume margin in helical tomotherapy for prostate cancer: Is there a preferred method?

    NASA Astrophysics Data System (ADS)

    Cao, Yuan Jie; Lee, Suk; Chang, Kyung Hwan; Shim, Jang Bo; Kim, Kwang Hyeon; Jang, Min Sun; Yoon, Won Sup; Yang, Dae Sik; Park, Young Je; Kim, Chul Yong

    2015-07-01

    We compare the dosimetrical differences between plans generated for helical tomotherapy by using the 2D or 3D the margining technique for the treatment of prostate cancer. Ten prostate cancer patients were included in this study. For 2D plans, the planning target volume (PTV) was created by adding 5 mm (lateral/anterior-posterior) to the clinical target volume (CTV). For 3D plans, a 5-mm margin was added not only lateral/anterior-posterior, but also superior-inferior, to the CTV. Various dosimetrical indices, including the prescription isodose to target volume (PITV) ratio, conformity index (CI), homogeneity index (HI), target coverage index (TCI), modified dose homogeneity index (MHI), conformation number (CN), critical organ scoring index (COSI), and quality factor (QF) were determined to compare the different treatment plans. Differences between the 2D and the 3D PTV indices were not significant except for the CI (p = 0.023). 3D margin plans (11195 MUs) resulted in higher (13.0%) monitor units than 2D margin plans (9728 MUs). There were no significant differences in any organs at risk (OARs) between the 2D and the 3D plans. Overall, the average dose for the 2D plan was slightly lower than that for the 3D plan dose. Compared to the 2D plan, the 3D plan increased the average treatment time by 1.5 minutes; however, this difference was not statistically significant (p = 0.082). We confirmed that the 2D and the 3D margin plans were not significantly different with regard to various dosimetric indices such as the PITV, CI, and HI for PTV and the OARs with tomotherapy.

  6. Jostling for position: optimizing linker location in the design of estrogen receptor-targeting PROTACs.

    PubMed

    Cyrus, Kedra; Wehenkel, Marie; Choi, Eun-Young; Lee, Hyosung; Swanson, Hollie; Kim, Kyung-Bo

    2010-07-01

    Estrogen receptor-alpha (ER) antagonists have been widely used for breast cancer therapy. Despite initial responsiveness, hormone-sensitive ER-positive cancer cells eventually develop resistance to ER antagonists. It has been shown that in most of these resistant tumor cells, the ER is expressed and continues to regulate tumor growth. Recent studies indicate that tamoxifen initially acts as an antagonist, but later functions as an ER agonist, promoting tumor growth. This suggests that targeted ER degradation may provide an effective therapeutic approach for breast cancers, even those that are resistant to conventional therapies. With this in mind, we previously demonstrated that proteolysis targeting chimeras (PROTACs) effectively induce degradation of the ER as a proof-of-concept experiment. Herein we further refined the PROTAC approach to target the ER for degradation. The ER-targeting PROTACs are composed of an estradiol on one end and a hypoxia-inducing factor 1alpha (HIF-1alpha)-derived synthetic pentapeptide on the other. The pentapeptide is recognized by an E3 ubiquitin ligase called the von Hippel Lindau tumor suppressor protein (pVHL), thereby recruiting the ER to this E3 ligase for ubiquitination and degradation. Specifically, the pentapeptide is attached at three different locations on estradiol to generate three different PROTAC types. With the pentapeptide linked through the C7alpha position of estradiol, the resulting PROTAC shows the most effective ER degradation and highest affinity for the estrogen receptor. This result provides an opportunity to develop a novel type of ER antagonist that may overcome the resistance of breast tumors to conventional drugs such as tamoxifen and fulvestrant (Faslodex). PMID:20512796

  7. Application of optimally scaled target factor analysis for assessing source contribution of ambient PM10.

    PubMed

    Escrig, Alberto; Monfort, Eliseo; Celades, Irina; Querol, Xavier; Amato, Fulvio; Minguillón, María Cruz; Hopke, Philip K

    2009-11-01

    Speciated coarse particulate matter (PM10) data obtained at three air quality monitoring sites in a highly industrialized area in Spain between 2002 and 2007 were analyzed for assessing source contribution of ambient particulate matter (PM). The source apportionment of PM in this area is an especially difficult task. There are industrial mineral dust emissions that need to be separately quantified from the natural sources of mineral PM. On the other hand, the diversity of industrial processes in the area results in a puzzling industrial emissions scenario. To solve this complex problem, a two-step methodology based on the possibilities of the Multilinear Engine was used. Application of positive matrix factorization to the dataset allowed the identification of nine factors relevant to the study area. This preliminary analysis permitted resolving two mineral factors. As a second step, a target rotation was implemented for transforming the mineral factors into experimentally characterized soil resuspension and industrial clay sources. In addition to improving the physical interpretation of these factors, the target rotation reduced the errors arising from the rotational freedom of the solution and the multicollinearity among sources. In this way, the main primary industrial emissions of PM in the zone were identified by this target factor analysis. A marked decrease was observed between 2002 and 2007 for the contributions of industrial sources coinciding with the implementation of mitigation measures in their processes. This study supports the utility of source apportionment methodologies for quantitatively evaluating the effectiveness of the abatement programs for air quality improvement. PMID:19947111

  8. The Search for Biosignatures on Mars: Using Predictive Geology to Optimize Exploration Targets

    NASA Technical Reports Server (NTRS)

    Oehler, Dorothy Z.; Allen, Carlton C.

    2011-01-01

    Predicting geologic context from satellite data is a method used on Earth for exploration in areas with limited ground truth. The method can be used to predict facies likely to contain organic-rich shales. Such shales concentrate and preserve organics and are major repositories of organic biosignatures on Earth [1]. Since current surface conditions on Mars are unfavorable for development of abundant life or for preservation of organic remains of past life, the chances are low of encountering organics in surface samples. Thus, focusing martian exploration on sites predicted to contain organic-rich shales would optimize the chances of discovering evidence of life, if it ever existed on that planet.

  9. Optimum placement of controls for static deformations of space structures

    NASA Technical Reports Server (NTRS)

    Haftka, R. T.

    1983-01-01

    The placement of thermal or force actuators to control slowly varying disturbances in the shape of large space structures is investigated analytically. Expressions are derived based on disturbances defined as the worst linear combination of a given set of functions and minimized numerically using the NEWSUMT optimization package. Results are presented in tables and graphs for a free-free beam with equidistant controls and polynomial-form (order 2-6) disturbances. Control placement is found to be of greater importance for force actuators, but is also of significance for thermal actuators.

  10. Jostling for Position: Optimizing Linker Location in the Design of Estrogen Receptor-targeting PROTACs

    PubMed Central

    Cyrus, Kedra; Wehenkel, Marie; Choi, Eun-Young; Lee, Hyosung; Swanson, Hollie

    2012-01-01

    Estrogen receptor-alpha (ER) antagonists have been widely used for breast cancer therapy. Despite initial responsiveness, eventually hormone-sensitive ER-positive cancer cells develop resistance to ER antagonists. It has been shown that, in most of these resistant tumor cells, the ER is expressed and continues to regulate tumor growth. Recent studies propose that tamoxifen initially acts as an antagonist but later functions as an ER agonist, promoting tumor growth. This suggests that targeted ER degradation may provide an effective therapeutic approach for breast cancers, even those which are resistant to conventional therapies. With this in mind, we previously demonstrated that PROTACs effectively induce degradation of the ER as a proof of concept experiment. Herein, we further refined the PROTAC approach to target the ER for degradation. The ER-targeting PROTACs are composed of an estradiol on one end and Hypoxia Inducing Factor 1α (HIF-1α)-derived synthetic pentapeptide on the other. The pentapeptide is recognized by an E3 ubiquitin ligase called the von Hippel Lindau tumor suppressor protein (pVHL), thereby recruiting the ER to this E3 ligase for ubiquitination and degradation. Specifically, the pentapeptide is attached at three different locations on estradiol to generate three different types of PROTACs. When the pentapeptide is linked through the C-7α position of estradiol, the resulting PROTAC showed the most effective ER degradation and best affinity for the estrogen receptor. This result provides an opportunity to develop a novel type of ER antagonist that may overcome the resistance of breast tumor to conventional drugs, such as tamoxifen and fulvestrant (Faslodex™). PMID:20512796

  11. Investigating the cubosomal ability for transnasal brain targeting: In vitro optimization, ex vivo permeation and in vivo biodistribution.

    PubMed

    Abdelrahman, Fatma Elzahraa; Elsayed, Ibrahim; Gad, Mary Kamal; Badr, Ahmed; Mohamed, Magdi Ibrahim

    2015-07-25

    The aim of this study was to enhance the risperidone delivery to the brain through the transnasal route via optimization of cubosomal gel. Cubosomes were prepared using glycerol mono-oleate (GMO), Pluronic F127 (PF127) and Tween 80 (T80). The prepared formulae were characterized by testing their particle size, polydispersity index, zeta potential, entrapment efficiency, in vitro drug release and transmission electron microscopy. Central composite design was planned for the formulae optimization and the selected formula (containing PF127 with concentration 15 mg/g GMO and T80 with concentration of 20mg/L) was re-prepared in presence of gelling polymer (gellan gum or polyox). The optimal cubosomal gel (containing 0.4% w/v polyox) had been subjected to ex-vivo permeation, histopathological evaluation and in vivo biodistribution studies. It showed significantly higher transnasal permeation and better distribution to the brain, when compared to the used control (drug solution and/or suspension). Finally, the cubosomal gel could be considered as a promising carrier for brain targeting of CNS acting drugs through the transnasal route. PMID:26026251

  12. Physiological geroscience: targeting function to increase healthspan and achieve optimal longevity.

    PubMed

    Seals, Douglas R; Justice, Jamie N; LaRocca, Thomas J

    2016-04-15

    Most nations of the world are undergoing rapid and dramatic population ageing, which presents great socio-economic challenges, as well as opportunities, for individuals, families, governments and societies. The prevailing biomedical strategy for reducing the healthcare impact of population ageing has been 'compression of morbidity' and, more recently, to increase healthspan, both of which seek to extend the healthy period of life and delay the development of chronic diseases and disability until a brief period at the end of life. Indeed, a recently established field within biological ageing research, 'geroscience', is focused on healthspan extension. Superimposed on this background are new attitudes and demand for 'optimal longevity' - living long, but with good health and quality of life. A key obstacle to achieving optimal longevity is the progressive decline in physiological function that occurs with ageing, which causes functional limitations (e.g. reduced mobility) and increases the risk of chronic diseases, disability and mortality. Current efforts to increase healthspan centre on slowing the fundamental biological processes of ageing such as inflammation/oxidative stress, increased senescence, mitochondrial dysfunction, impaired proteostasis and reduced stress resistance. We propose that optimization of physiological function throughout the lifespan should be a major emphasis of any contemporary biomedical policy addressing global ageing. Effective strategies should delay, reduce in magnitude or abolish reductions in function with ageing (primary prevention) and/or improve function or slow further declines in older adults with already impaired function (secondary prevention). Healthy lifestyle practices featuring regular physical activity and ideal energy intake/diet composition represent first-line function-preserving strategies, with pharmacological agents, including existing and new pharmaceuticals and novel 'nutraceutical' compounds, serving as potential

  13. Phenotypic side effects prediction by optimizing correlation with chemical and target profiles of drugs.

    PubMed

    Kanji, Rakesh; Sharma, Abhinav; Bagler, Ganesh

    2015-11-01

    Despite technological progresses and improved understanding of biological systems, discovery of novel drugs is an inefficient, arduous and expensive process. Research and development cost of drugs is unreasonably high, largely attributed to the high attrition rate of candidate drugs due to adverse drug reactions. Computational methods for accurate prediction of drug side effects, rooted in empirical data of drugs, have the potential to enhance the efficacy of the drug discovery process. Identification of features critical for specifying side effects would facilitate efficient computational procedures for their prediction. We devised a generalized ordinary canonical correlation model for prediction of drug side effects based on their chemical properties as well as their target profiles. While the former is based on 2D and 3D chemical features, the latter enumerates a systems-level property of drugs. We find that the model incorporating chemical features outperforms that incorporating target profiles. Furthermore we identified the 2D and 3D chemical properties that yield best results, thereby implying their relevance in specifying adverse drug reactions. PMID:26252576

  14. Targeted near infrared hyperthermia combined with immune stimulation for optimized therapeutic efficacy in thyroid cancer treatment

    PubMed Central

    Zhou, Le; Zhang, Mengchao; Fu, Qingfeng; Li, Jingting; Sun, Hui

    2016-01-01

    Treatment of thyroid cancer has incurred much focus because of its high prevalency. As a new strategy treating thyroid cancer, hyperthermia takes several advantages compared with surgery or chemotherapy, including minimal invasion, low systematic toxicity and the ability to enhance the immunogenicity of cancer cells with the expression Hsp70 which serves as Toll-like receptors-4 (TLR-4 agonist). However, Hsp70 as a molecular chaperone can protect cells from heat induced apoptosis and therefore compromise the tumor killing effect of hyperthermia. In this study, to solve this problem, a combined hyperthermia therapy was employed to treat thyroid cancer. We prepared a probe with the tumor targeting agent AG to monitor thyroid tumor issue and generate heat to kill tumor cells in vivo. At the same time Quercetin (inhibitor of HSP70) and lipopolysaccharide (LPS) (agonist of TLR-4) were used for the combined hyperthermia therapy. The results showed that compared with free IR820, AG modification facilitated much enhanced cellular uptake and greatly pronounced tumor targeting ability. The combined therapy exhibited the most remarkable tumor inhibition compared with the single treatments both in vitro and in vivo. These findings verified that the new therapeutic combination could significantly improve the effect of hyperthermia and shed light on a novel clinical strategy in thyroid cancer treatment. PMID:26769848

  15. OptForce: An Optimization Procedure for Identifying All Genetic Manipulations Leading to Targeted Overproductions

    PubMed Central

    Ranganathan, Sridhar; Suthers, Patrick F.; Maranas, Costas D.

    2010-01-01

    Computational procedures for predicting metabolic interventions leading to the overproduction of biochemicals in microbial strains are widely in use. However, these methods rely on surrogate biological objectives (e.g., maximize growth rate or minimize metabolic adjustments) and do not make use of flux measurements often available for the wild-type strain. In this work, we introduce the OptForce procedure that identifies all possible engineering interventions by classifying reactions in the metabolic model depending upon whether their flux values must increase, decrease or become equal to zero to meet a pre-specified overproduction target. We hierarchically apply this classification rule for pairs, triples, quadruples, etc. of reactions. This leads to the identification of a sufficient and non-redundant set of fluxes that must change (i.e., MUST set) to meet a pre-specified overproduction target. Starting with this set we subsequently extract a minimal set of fluxes that must actively be forced through genetic manipulations (i.e., FORCE set) to ensure that all fluxes in the network are consistent with the overproduction objective. We demonstrate our OptForce framework for succinate production in Escherichia coli using the most recent in silico E. coli model, iAF1260. The method not only recapitulates existing engineering strategies but also reveals non-intuitive ones that boost succinate production by performing coordinated changes on pathways distant from the last steps of succinate synthesis. PMID:20419153

  16. Targeting the MET Pathway in Gastric and Oesophageal Cancers: Refining the Optimal Approach.

    PubMed

    Lee, J; Tran, P; Klempner, S J

    2016-08-01

    Gastric and oesophageal cancers are a major cause of global cancer-related morbidity and mortality. Improvements in treatment for locoregional and metastatic gastric and oesophageal cancer have been incremental and the overall prognosis remains poor. Increasingly, molecular classification has identified recurrent, therapeutically relevant, somatic alterations in gastroesophageal malignancies. However, other than ERBB2 amplification, molecularly directed therapies have not translated to improved survival. Amplification of the receptor tyrosine kinase MET is found in about 5% of gastroesophageal cancers and represents an oncogenic driver and therapeutic target. Small series have shown activity of MET-directed tyrosine kinase inhibitors, but the clinical benefit of anti-MET antibodies has been disappointing. Here we discuss the MET pathway in gastroesophageal cancers, the clinical data for MET small molecule tyrosine kinase inhibitors, anti-MET antibodies and future clinical directions for targeting MET in gastric and oesophageal cancers. To our knowledge, this is the most comprehensive review of the clinical experience with MET-directed therapies in gastric and oesophageal cancers. PMID:26880063

  17. Fabrication of optimized oil-water separation devices through the targeted treatment of silica meshes

    NASA Astrophysics Data System (ADS)

    Crick, Colin R.; Tunali Ozkan, Feyza; Parkin, Ivan P.

    2015-10-01

    Efficient oil-water separation is achieved using an optimized superhydrophobic material, generated by the zeolitic roughening and subsequent hydrophobic surface treatment of silica filter membranes. The material is both highly rough and intrinsically hydrophobic, resulting in superhydrophobic membranes which show a substantial affinity for hydrophobic solvents and oils. The membranes are syringe-mounted, suction pressure is applied and the selective collection of oil is achieved. The membranes are extremely robust, which is a result of the zeolitic roughening process, they possess small pores (0.7 μm), as a result these devices can perform complete separation and operate at a range of suction pressures. The devices could be readily used in a range of real-world applications, including oil spill clean-up and industrial filters.

  18. Amidated pectin/sodium carboxymethylcellulose microspheres as a new carrier for colonic drug targeting: Development and optimization by factorial design.

    PubMed

    Gadalla, Hytham H; El-Gibaly, Ibrahim; Soliman, Ghareb M; Mohamed, Fergany A; El-Sayed, Ahmed M

    2016-11-20

    The colon is a promising site for drug targeting owing to its long transit time and mild proteolytic activity. The aim of this study was to prepare new low methoxy amidated pectin/NaCMC microspheres cross-linked by a mixture of Zn(2+) and Al(3+) ions and test their potential for colonic targeting of progesterone. A 2(4) factorial design was carried out to optimize the preparation conditions. High drug entrapment efficiency (82-99%) was obtained and it increased with increasing drug concentration but decreased with increasing polymer concentration. Drug release rate was directly proportional to the microsphere drug content and inversely related to Al(3+) ion concentration. Drug release was minimal during the first 3h but was significantly improved in the presence of 1% rat caecal contents, confirming the microsphere potential for colonic delivery. The microspheres achieved >2.3-fold enhancement of colonic progesterone permeability. These results confirm the viability of the produced microspheres as colon-targeted drug delivery vehicle. PMID:27561525

  19. Modelling targets for anticancer drug control optimization in physiologically structured cell population models

    NASA Astrophysics Data System (ADS)

    Billy, Frédérique; Clairambault, Jean; Fercoq, Olivier; Lorenzi, Tommaso; Lorz, Alexander; Perthame, Benoît

    2012-09-01

    The main two pitfalls of therapeutics in clinical oncology, that limit increasing drug doses, are unwanted toxic side effects on healthy cell populations and occurrence of resistance to drugs in cancer cell populations. Depending on the constraint considered in the control problem at stake, toxicity or drug resistance, we present two different ways to model the evolution of proliferating cell populations, healthy and cancer, under the control of anti-cancer drugs. In the first case, we use a McKendrick age-structured model of the cell cycle, whereas in the second case, we use a model of evolutionary dynamics, physiologically structured according to a continuous phenotype standing for drug resistance. In both cases, we mention how drug targets may be chosen so as to accurately represent the effects of cytotoxic and of cytostatic drugs, separately, and how one may consider the problem of optimisation of combined therapies.

  20. Dry Ribbon for Heated Head Automated Fiber Placement

    NASA Technical Reports Server (NTRS)

    Hulcher, A. Bruce; Marchello, Joseph M.; Hinkley, Jeffrey A.; Johnston, Norman J.; Lamontia, Mark A.

    2000-01-01

    Ply-by-ply in situ processes involving automated heated head deposition are being developed for fabrication of high performance, high temperature composite structures from low volatile content polymer matrices. This technology requires (1) dry carbon fiber towpreg, (2) consolidation of towpreg to quality, placement-grade unidirectional ribbon or tape, and (3) rapid, in situ, accurate, ply-by-ply robotic placement and consolidation of this material to fabricate a composite structure. In this study, the physical properties of a candidate thermoplastic ribbon, PIXA/IM7, were evaluated and screened for suitability in robotic placement. Specifically, towpreg was prepared from PIXA powder. Various conditions (temperatures) were used to convert the powder-coated towpreg to ribbons with varying degrees of processability. Ribbon within preset specifications was fabricated at 3 temperatures: 390, 400 and 410 C. Ribbon was also produced out-of-spec by purposely overheating the material to a processing temperature of 450 C. Automated placement equipment at Cincinnati Milacron and NASA Langley was used to fabricate laminates from these experimental ribbons. Ribbons were placed at 405 and 450 C by both sets of equipment. Double cantilever beam and wedge peel tests were used to determine the quality of the laminates and, especially, the interlaminar bond formed during the placement process. Ribbon made under conditions expected to be non-optimal (overheated) resulted in poor placeability and composites with weak interlaminar bond strengths, regardless of placement conditions. Ribbon made under conditions expected to be ideal showed good processability and produced well-consolidated laminates. Results were consistent from machine to machine and demonstrated the importance of ribbon quality in heated-head placement of dry material forms. Preliminary screening criteria for the development and evaluation of ribbon from new matrix materials were validated.

  1. Direct induction of apoptosis using an optimal mitochondrially targeted p53.

    PubMed

    Mossalam, Mohanad; Matissek, Karina J; Okal, Abood; Constance, Jonathan E; Lim, Carol S

    2012-05-01

    Targeting the tumor suppressor p53 to the mitochondria triggers a rapid apoptotic response as efficiently as transcription-dependent p53. (1, 2) p53 forms a complex with the antiapoptotic Bcl-XL, which leads to Bak and Bax oligomerization resulting in apoptosis via mitochondrial outer membrane permeabilization. (3, 4) Although p53 performs its main role in the mitochondrial outer membrane, it also interacts with different proteins in the mitochondrial inner membrane and matrix. (5, 6) To further investigate mitochondrial activity of p53, EGFP-p53 was fused to different mitochondrial targeting signals (MTSs) directing it to the mitochondrial outer membrane ("XL-MTS" from Bcl-XL; "TOM-MTS" from TOM20), the inner membrane ("CCO-MTS" from cytochrome c oxidase), or matrix ("OTC-MTS" from ornithine transcarbamylase). Fluorescence microscopy and a p53 reporter dual luciferase assay demonstrated that fusing MTSs to p53 increased mitochondrial localization and nuclear exclusion depending on which MTS was used. To examine if the MTSs initiate mitochondrial damage, we fused each individual MTS to EGFP (a nontoxic protein) as negative controls. We performed caspase-9, TUNEL, annexin-V, and 7-AAD apoptosis assays on T47D breast cancer cells transfected with mitochondrial constructs. Except for EGFP-XL, apoptotic potential was observed in all MTS-EGFP-p53 and MTS-EGFP constructs. In addition, EGFP-p53-XL showed the greatest significant increase in programmed cell death compared to its nontoxic MTS control (EGFP-XL). The apoptotic mechanism for each construct was further investigated using pifithrin-α (an inhibitor of p53 transcriptional activity), pifithrin-μ (a small molecule that reduces binding of p53 to Bcl-2 and Bcl-XL), and overexpressing the antiapoptotic Bcl-XL. Unlike the MTSs from TOM, CCO, and OTC, which showed different apoptotic mechanisms, we conclude that p53 fused to the MTS from Bcl-XL performs its apoptotic potential exclusively through the p53/Bcl

  2. DIRECT INDUCTION OF APOPTOSIS USING AN OPTIMAL MITOCHONDRIALLY TARGETED P53

    PubMed Central

    Mossalam, Mohanad; Matissek, Karina J.; Okal, Abood; Constance, Jonathan E.; Lim, Carol S.

    2012-01-01

    Targeting the tumor suppressor p53 to the mitochondria triggers a rapid apoptotic response as efficiently as transcription-dependent p53.1, 2 p53 forms a complex with the anti-apoptotic Bcl-XL, which leads to Bak and Bax oligomerization resulting in apoptosis via mitochondrial outer membrane permeabilization.3, 4 Although p53 performs its main role in the mitochondrial outer membrane it also interacts with different proteins in the mitochondrial inner membrane and matrix.5, 6 To further investigate mitochondrial activity of p53, EGFP-p53 was fused to different mitochondrial targeting signals (MTSs) directing it to the mitochondrial outer membrane (“XL-MTS” from Bcl-XL; “TOM-MTS” from TOM20), the inner membrane (“CCO-MTS” from cytochrome c oxidase) or matrix (“OTC-MTS” from ornithine transcarbamylase). Fluorescence microscopy and a p53 reporter dual luciferase assay demonstrated that fusing MTSs to p53 increased mitochondrial localization and nuclear exclusion depending on which MTS was used. To examine if the MTSs initiate mitochondrial damage, we fused each individual MTS to EGFP (a non-toxic protein) as negative controls. We performed caspase-9, TUNEL, Annexin-V, and 7-AAD apoptosis assays on T47D breast cancer cells transfected with mitochondrial constructs. Except for EGFP-XL, apoptotic potential was observed in all MTS-EGFP-p53 and MTS-EGFP constructs. In addition, EGFP-p53-XL showed the greatest significant increase in programmed cell death compared to its non-toxic MTS control (EGFP-XL). The apoptotic mechanism for each construct was further investigated using pifithrin-α (an inhibitor of p53 transcriptional activity), pifithrin-μ (a small molecule that reduces binding of p53 to Bcl-2 and Bcl-XL), and over-expressing the anti-apoptotic Bcl-XL. Unlike the MTSs from TOM, CCO, and OTC, which showed different apoptotic mechanisms, we conclude that p53 fused to the MTS from Bcl-XL performs its apoptotic potential exclusively through p53/Bcl

  3. Live-cell CLEM of subcellular targets: an optimized procedure for polymer-based imaging substrates.

    PubMed

    Padman, Benjamin S; Ramm, Georg

    2014-01-01

    Live-cell correlative light and electron microscopy permits the visualization of ultrastructure details associated with dynamic biological processes. On the optical level, fluorescence microscopy can be further combined with functional studies of intracellular processes and manipulation of biological samples using laser light. However, the major challenge is to relocate intracellular compartments in three dimensions after the sample has undergone an extensive EM sample preparation process. Here, we describe a detailed protocol for live-cell CLEM that provides easy guidance for 3D relocalization. Based on the use of the novel polymer film TOPAS as direct imaging substrate, we provide a setup that uses highly visible toner particles for tracking the region of interest in 2D and fiducial markers for the 3D relocation of intracellular structures. An example is given where a single mitochondria is targeted by laser microirradiation in live-cell fluorescence microscopy. After relocating the same structure in 3D in serial EM sections, the changes to the mitochondrial ultrastructure are observed by TEM. The method is suitable for correlation of live-cell microscopy of cells and can be performed using any inverted optical microscope. PMID:25287846

  4. Optimal target localization for subthalamic stimulation in patients with Parkinson disease

    PubMed Central

    Schüpbach, Michael; Czernecki, Virginie; Karachi, Carine; Fernandez-Vidal, Sara; Golmard, Jean-Louis; Serra, Giulia; Navarro, Soledad; Welaratne, Arlette; Hartmann, Andréas; Mesnage, Valérie; Pineau, Fanny; Cornu, Philippe; Pidoux, Bernard; Worbe, Yulia; Zikos, Panayiotis; Grabli, David; Galanaud, Damien; Bonnet, Anne-Marie; Belaid, Hayat; Dormont, Didier; Vidailhet, Marie; Mallet, Luc; Houeto, Jean-Luc; Bardinet, Eric; Yelnik, Jerome; Agid, Yves

    2014-01-01

    Objective: To further determine the causes of variable outcome from deep brain stimulation of the subthalamic nucleus (DBS-STN) in patients with Parkinson disease (PD). Methods: Data were obtained from our cohort of 309 patients with PD who underwent DBS-STN between 1996 and 2009. We examined the relationship between the 1-year motor, cognitive, and psychiatric outcomes and (1) preoperative PD clinical features, (2) MRI measures, (3) surgical procedure, and (4) locations of therapeutic contacts. Results: Pre- and postoperative results were obtained in 262 patients with PD. The best motor outcome was obtained when stimulating contacts were located within the STN as compared with the zona incerta (64% vs 49% improvement). Eighteen percent of the patients presented a postoperative cognitive decline, which was found to be principally related to the surgical procedure. Other factors predictive of poor cognitive outcome were perioperative confusion and psychosis. Nineteen patients showed a stimulation-induced hypomania, which was related to both the form of the disease (younger age, shorter disease duration, higher levodopa responsiveness) and the ventral contact location. Postoperative depression was more frequent in patients already showing preoperative depressive and/or residual axial motor symptoms. Conclusion: In this homogeneous cohort of patients with PD, we showed that (1) the STN is the best target to improve motor symptoms, (2) postoperative cognitive deficit is mainly related to the surgery itself, and (3) stimulation-induced hypomania is related to a combination of both the disease characteristics and a more ventral STN location. PMID:24647024

  5. Optimized multimodal nanoplatforms for targeting α(v)β3 integrins.

    PubMed

    Bolley, Julie; Lalatonne, Yoann; Haddad, Oualid; Letourneur, Didier; Soussan, Michael; Pérard-Viret, Joelle; Motte, Laurence

    2013-12-01

    Magnetic Resonance Imaging (MRI) using contrast agents is a very powerful technique for diagnosis in clinical medicine and biomedical research. The synthesis of ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles targeting αvβ3 integrins and acting as new MRI contrast agents seems to be a promising way for cancer diagnosis. Indeed, it is well established that αvβ3 integrin plays a key role in tumor angiogenesis acting like a receptor for the extracellular matrix proteins like vitronectin, fibronectin through the arginine-glycine-aspartic acid (RGD) sequence. Up-regulation of αvβ3 has been found to be associated with a wide range of cancers, making it a broad-spectrum tumor-marker. In this study, USPIO nanocrystals were synthesized and surface passivated with caffeic acid. The large number of the carboxylic acid functions at the outer surface of the nanoplatforms was used for the covalent coupling of Rhodamine123, polyethylene glycol (PEG) and cyclic RGD. Soluble carbodiimide (EDC) and N-hydroxysuccinimide (NHS) were used to crosslink carboxylic acid with the amino group of the ligands. We examined the design of the nanoplatforms with each individual entity and then the combination of two and three of them. Several methods were used to characterize the nanoparticle surface functionalization and the magnetic properties of these contrast agents were studied using a 1.5 T clinical MRI scanner. The affinity towards integrins was evidenced by surface plasmon resonance and solid-phase receptor-binding assay. PMID:24154564

  6. Isotype-Specific Inhibition of Histone Deacetylases: Identification of Optimal Targets for Radiosensitization

    PubMed Central

    Kim, Jin Ho; Moon, Sung Ho; No, Mina; Kim, Jae Jin; Choi, Eun Jung; Cho, Bong Jun; Kim, Jae Sung; Kim, Il Han; Kim, In Ah

    2016-01-01

    Purpose Histone deacetylase (HDAC) inhibitors radiosensitize tumor cells. To elucidate mechanisms underlying radiosensitization by HDAC inhibition, understanding of differential contributions of HDAC isotypes is needed. The aim of this study was to investigate involvement of known HDAC isotypes in modulation of cellular radiosensitivity. Materials and Methods Because pharmacologic HDAC inhibitors lack isotype-specificity, RNA interference against 11 HDAC isotypes was used to inhibit HDAC in an isotype-specific manner. Radiation cell survival was evaluated using a clonogenic assay in SQ20B cells transfected with small interfering RNA specifically targeting HDAC isotypes. Immunocytochemistry was performed for detection of γH2AX foci. Protein expression was measured using Western blotting. Results Among 11 HDAC isotypes tested, specific inhibition of 7 isotypes (HDAC1, HDAC3, HDAC4, HDAC6, HDAC7, HDAC10, and HDAC11) enhanced radiation lethality in SQ20B cells. Radiosensitization by inhibition of these HDAC isotypes was accompanied by delay of DNA double strand break repair. Radiosensitivity of SQ20B cells was not altered by selective inhibition of the remaining four isotypes (HDAC2, HDAC5, HDAC8, and HDAC9). Inhibition of HDAC isotypes resulted in downregulation of various proteins involved in pro-survival and DNA damage repair pathways. Conclusion Isotype-specificity exists in HDAC inhibition-induced radiosensitization. Different HDAC isotypes are differentially involved in modulation of cellular radiosensitivity. PMID:26582395

  7. Optimizing the sequence of anti-EGFR-targeted therapy in EGFR-mutant lung cancer.

    PubMed

    Meador, Catherine B; Jin, Hailing; de Stanchina, Elisa; Nebhan, Caroline A; Pirazzoli, Valentina; Wang, Lu; Lu, Pengcheng; Vuong, Huy; Hutchinson, Katherine E; Jia, Peilin; Chen, Xi; Eisenberg, Rosana; Ladanyi, Marc; Politi, Katerina; Zhao, Zhongming; Lovly, Christine M; Cross, Darren A E; Pao, William

    2015-02-01

    Metastatic EGFR-mutant lung cancers are sensitive to the first- and second-generation EGFR tyrosine kinase inhibitors (TKIs) gefitinib, erlotinib, and afatinib, but resistance develops. Acquired resistance to gefitinib or erlotinib occurs most commonly (>50%) via the emergence of a second-site EGFR mutation, T790M. Two strategies to overcome T790M-mediated resistance are dual inhibition of EGFR with afatinib plus the anti-EGFR antibody cetuximab (A+C), or mutant-specific EGFR inhibition with AZD9291. A+C and AZD9291 are now also being tested as first-line therapies, but whether these therapies will extend progression-free survival or induce more aggressive forms of resistance in this setting remains unknown. We modeled resistance to multiple generations of anti-EGFR therapies preclinically to understand the effects of sequential treatment with anti-EGFR agents on drug resistance and determine the optimal order of treatment. Using a panel of erlotinib/afatinib-resistant cells, including a novel patient-derived cell line (VP-2), we found that AZD9291 was more potent than A+C at inhibiting cell growth and EGFR signaling in this setting. Four of four xenograft-derived A+C-resistant cell lines displayed in vitro and in vivo sensitivity to AZD9291, but four of four AZD9291-resistant cell lines demonstrated cross-resistance to A+C. Addition of cetuximab to AZD9291 did not confer additive benefit in any preclinical disease setting. This work, emphasizing a mechanistic understanding of the effects of therapies on tumor evolution, provides a framework for future clinical trials testing different treatment sequences. This paradigm is applicable to other tumor types in which multiple generations of inhibitors are now available. PMID:25477325

  8. Optimizing the sequence of anti-EGFR targeted therapy in EGFR-mutant lung cancer

    PubMed Central

    Meador, Catherine B.; Jin, Hailing; de Stanchina, Elisa; Nebhan, Caroline A.; Pirazzoli, Valentina; Wang, Lu; Lu, Pengcheng; Vuong, Huy; Hutchinson, Katherine E.; Jia, Peilin; Chen, Xi; Eisenberg, Rosana; Ladanyi, Marc; Politi, Katerina; Zhao, Zhongming; Lovly, Christine M.; Cross, Darren A. E.; Pao, William

    2015-01-01

    Metastatic EGFR-mutant lung cancers are sensitive to the first- and second- generation EGFR tyrosine kinase inhibitors (TKIs), gefitinib, erlotinib, and afatinib, but resistance develops. Acquired resistance (AR) to gefitinib or erlotinib occurs most commonly (>50%) via the emergence of a second-site EGFR mutation, T790M. Two strategies to overcome T790M-mediated resistance are dual inhibition of EGFR with afatinib plus the anti-EGFR antibody, cetuximab (A+C), or mutant-specific EGFR inhibition with AZD9291. A+C and AZD9291 are now also being tested as first-line therapies, but whether these therapies will extend progression-free survival or induce more aggressive forms of resistance in this setting remains unknown. We modeled resistance to multiple generations of anti-EGFR therapies preclinically in order to understand the effects of sequential treatment with anti-EGFR agents on drug resistance and determine the optimal order of treatment. Using a panel of erlotinib/afatinib-resistant cells including a novel patient-derived cell line (VP-2), we found that AZD9291 was more potent than A+C at inhibiting cell growth and EGFR signaling in this setting. 4 of 4 xenograft-derived A+C-resistant cell lines displayed in vitro and in vivo sensitivity to AZD9291, but 4 of 4 AZD9291-resistant cell lines demonstrated cross-resistance to A+C. Addition of cetuximab to AZD9291 did not confer additive benefit in any preclinical disease setting. This work, emphasizing a mechanistic understanding of the effects of therapies on tumor evolution, provides a framework for future clinical trials testing different treatment sequences. This paradigm is applicable to other tumor types in which multiple generations of inhibitors are now available. PMID:25477325

  9. Effective conflict resolution strategies for SRAF placement

    NASA Astrophysics Data System (ADS)

    Ganjugunte, Shashidhara K.; Strecker, Norbert; Jayaram, Srividya; LaCour, Pat; Torunoglu, Ilhami

    2015-07-01

    Sub-Resolution Assist Features (SRAFs) have emerged as a key technology to enable semiconductor manufacturing for advanced technology nodes. SRAF placement is required to adhere to manufacturability constraints (MRC). MRC specifications are distance and size constraints specified by the user to ensure SRAFs are not detrimental to the final target shapes being printed. Conceptually, SRAF placement can be divided into two steps - SRAF candidate generation and SRAF candidate cleanup or conflict resolution. SRAFs generated as candidates may not adhere to MRC constraints. It is during the cleanup/conflict resolution process that the MRC constraints are enforced. In this paper we focus on the latter phase - cleanup. The goal of the cleanup phase is to retain as much of the initial candidates as possible, and, if necessary, transform them to adhere to MRC conditions. An SRAF is said to be in conflict with another shape if it violates the distance MRC constraint. One can model these conflicts using a conflict graph G=(V,E), whose vertices V correspond to geometric shapes involved in a conflict and an edge is present in E, between two vertices if the corresponding shapes are involved in a conflict. A weight is associated with each vertex that could, for example, correspond to area of the corresponding shape. The goal of conflict resolution then, is to find a transformation of the vertices so that the resulting graph is conflict free while maximizing the weight of vertices retained. This can be viewed as a generalization of the computationally hard problem of finding the largest independent set of candidates, albeit allowing for transformation. The transformations we allow include deletion, splitting, resizing, merge, and bounded translation. In this paper, we describe an approach which classifies the conflicts and apply appropriate transformations to achieve effective SRAF placement. Further, we demonstrate that such a strategy reduces the number of rules to be specified by

  10. Extension for prevention: margin placement.

    PubMed

    Larson, Thomas D

    2012-01-01

    This article will review the concept of extension for prevention popularized by G.V. Black around the early 1900s. Concepts of extension and prevention have changed over the years with a more informed knowledge of the caries process, improved materials, cutting instruments, and techniques. The reasons for placement of the outline form relative to the tooth morphology, gingival tissue, relationship to adjacent teeth, and the choice of material will be described for all of the materials used in restorative dentistry. Research will be cited to support the scientific basis for outline form placement. PMID:22662468

  11. Alginate-whey protein dry powder optimized for target delivery of essential oils to the intestine of chickens.

    PubMed

    Zhang, Y; Gong, J; Yu, H; Guo, Q; Defelice, C; Hernandez, M; Yin, Y; Wang, Q

    2014-10-01

    In poultry production, there is a lack of effective and convenient approaches to deliver bioactive compounds such as some essential oils, which have been proposed as alternatives to antibiotic growth promoters. The objective of this research was to develop a method for target delivery of essential oils in feed to the lower intestines of chickens. Carvacrol was used as a model essential oil, and 2 food-grade biopolymers, alginate and whey protein, were selected to encapsulate carvacrol in microparticles. The effects of a medium molecular weight alginate, a low molecular weight alginate (LBA), and whey protein concentrations on the properties of carvacrol-loaded microparticles were investigated using response surface methodology. The encapsulation efficiencies for all the tested formulations were ≥ 98% and carvacrol content in the dry microparticles was 72 ± 2% (wt/wt). The microparticles showed good gastric resistance and rapid intestinal release under simulated gastrointestinal conditions. Alginate concentrations had the strongest influence on the gastric resistance of microparticles, whereas whey protein was the dominant parameter in controlling the intestinal release. The concentration of LBA was found to be the critical factor affecting the mechanical strength of the microparticles. A predicted optimum formulation from in vitro optimization was tested in chickens. It was found that a negligible amount of carvacrol was detected in the intestines of chickens fed with unencapsulated carvacrol. Microparticles of predicted optimum formulation delivered a remarkably higher concentration of carvacrol to the jejunum and ileum regions. The high concentration was sustained for more than 3 h after oral administration. The in vivo release of carvacrol from the microparticles appeared faster than release from in vitro simulation. Nonetheless, the in vitro simulation provided good indications of the in vivo performance, and thus may serve as a useful tool for formula

  12. Optimized multimodal nanoplatforms for targeting αvβ3 integrins

    NASA Astrophysics Data System (ADS)

    Bolley, Julie; Lalatonne, Yoann; Haddad, Oualid; Letourneur, Didier; Soussan, Michael; Pérard-Viret, Joelle; Motte, Laurence

    2013-11-01

    Magnetic Resonance Imaging (MRI) using contrast agents is a very powerful technique for diagnosis in clinical medicine and biomedical research. The synthesis of ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles targeting αvβ3 integrins and acting as new MRI contrast agents seems to be a promising way for cancer diagnosis. Indeed, it is well established that αvβ3 integrin plays a key role in tumor angiogenesis acting like a receptor for the extracellular matrix proteins like vitronectin, fibronectin through the arginine-glycine-aspartic acid (RGD) sequence. Up-regulation of αvβ3 has been found to be associated with a wide range of cancers, making it a broad-spectrum tumor-marker. In this study, USPIO nanocrystals were synthesized and surface passivated with caffeic acid. The large number of the carboxylic acid functions at the outer surface of the nanoplatforms was used for the covalent coupling of Rhodamine123, polyethylene glycol (PEG) and cyclic RGD. Soluble carbodiimide (EDC) and N-hydroxysuccinimide (NHS) were used to crosslink carboxylic acid with the amino group of the ligands. We examined the design of the nanoplatforms with each individual entity and then the combination of two and three of them. Several methods were used to characterize the nanoparticle surface functionalization and the magnetic properties of these contrast agents were studied using a 1.5 T clinical MRI scanner. The affinity towards integrins was evidenced by surface plasmon resonance and solid-phase receptor-binding assay.Magnetic Resonance Imaging (MRI) using contrast agents is a very powerful technique for diagnosis in clinical medicine and biomedical research. The synthesis of ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles targeting αvβ3 integrins and acting as new MRI contrast agents seems to be a promising way for cancer diagnosis. Indeed, it is well established that αvβ3 integrin plays a key role in tumor angiogenesis acting like a receptor for

  13. Development of a Genus-Specific Antigen Capture ELISA for Orthopoxviruses - Target Selection and Optimized Screening.

    PubMed

    Stern, Daniel; Pauly, Diana; Zydek, Martin; Miller, Lilija; Piesker, Janett; Laue, Michael; Lisdat, Fred; Dorner, Martin B; Dorner, Brigitte G; Nitsche, Andreas

    2016-01-01

    Orthopoxvirus species like cowpox, vaccinia and monkeypox virus cause zoonotic infections in humans worldwide. Infections often occur in rural areas lacking proper diagnostic infrastructure as exemplified by monkeypox, which is endemic in Western and Central Africa. While PCR detection requires demanding equipment and is restricted to genome detection, the evidence of virus particles can complement or replace PCR. Therefore, an easily distributable and manageable antigen capture enzyme-linked immunosorbent assay (ELISA) for the detection of orthopoxviruses was developed to facilitate particle detection. By comparing the virus particle binding properties of polyclonal antibodies developed against surface-exposed attachment or fusion proteins, the surface protein A27 was found to be a well-bound, highly immunogenic and exposed target for antibodies aiming at virus particle detection. Subsequently, eight monoclonal anti-A27 antibodies were generated and characterized by peptide epitope mapping and surface plasmon resonance measurements. All antibodies were found to bind with high affinity to two epitopes at the heparin binding site of A27, toward either the N- or C-terminal of the crucial KKEP-segment of A27. Two antibodies recognizing different epitopes were implemented in an antigen capture ELISA. Validation showed robust detection of virus particles from 11 different orthopoxvirus isolates pathogenic to humans, with the exception of MVA, which is apathogenic to humans. Most orthopoxviruses could be detected reliably for viral loads above 1 × 103 PFU/mL. To our knowledge, this is the first solely monoclonal and therefore reproducible antibody-based antigen capture ELISA able to detect all human pathogenic orthopoxviruses including monkeypox virus, except variola virus which was not included. Therefore, the newly developed antibody-based assay represents important progress towards feasible particle detection of this important genus of viruses. PMID:26930499

  14. Optimization of anti-cancer drugs and a targeting molecule on multifunctional gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Rizk, Nahla; Christoforou, Nicolas; Lee, Sungmun

    2016-05-01

    Breast cancer is the most common and deadly cancer among women worldwide. Currently, nanotechnology-based drug delivery systems are useful for cancer treatment; however, strategic planning is critical in order to enhance the anti-cancer properties and reduce the side effects of cancer therapy. Here, we designed multifunctional gold nanoparticles (AuNPs) conjugated with two anti-cancer drugs, TGF-β1 antibody and methotrexate, and a cancer-targeting molecule, folic acid. First, optimum size and shape of AuNPs was selected by the highest uptake of AuNPs by MDA-MB-231, a metastatic human breast cancer cell line. It was 100 nm spherical AuNPs (S-AuNPs) that were used for further studies. A fixed amount (900 μl) of S-AuNP (3.8 × 108 particles/ml) was conjugated with folic acid-BSA or methotrexate-BSA. Methotrexate on S-AuNP induced cellular toxicity and the optimum amount of methotrexate-BSA (2.83 mM) was 500 μl. Uptake of S-AuNPs was enhanced by folate conjugation that binds to folate receptors overexpressed by MDA-MB-231 and the optimum uptake was at 500 μl of folic acid-BSA (2.83 mM). TGF-β1 antibody on S-AuNP reduced extracellular TGF-β1 of cancer cells by 30%. Due to their efficacy and tunable properties, we anticipate numerous clinical applications of multifunctional gold nanospheres in treating breast cancer.

  15. Optimization of anti-cancer drugs and a targeting molecule on multifunctional gold nanoparticles.

    PubMed

    Rizk, Nahla; Christoforou, Nicolas; Lee, Sungmun

    2016-05-01

    Breast cancer is the most common and deadly cancer among women worldwide. Currently, nanotechnology-based drug delivery systems are useful for cancer treatment; however, strategic planning is critical in order to enhance the anti-cancer properties and reduce the side effects of cancer therapy. Here, we designed multifunctional gold nanoparticles (AuNPs) conjugated with two anti-cancer drugs, TGF-β1 antibody and methotrexate, and a cancer-targeting molecule, folic acid. First, optimum size and shape of AuNPs was selected by the highest uptake of AuNPs by MDA-MB-231, a metastatic human breast cancer cell line. It was 100 nm spherical AuNPs (S-AuNPs) that were used for further studies. A fixed amount (900 μl) of S-AuNP (3.8 × 10(8) particles/ml) was conjugated with folic acid-BSA or methotrexate-BSA. Methotrexate on S-AuNP induced cellular toxicity and the optimum amount of methotrexate-BSA (2.83 mM) was 500 μl. Uptake of S-AuNPs was enhanced by folate conjugation that binds to folate receptors overexpressed by MDA-MB-231 and the optimum uptake was at 500 μl of folic acid-BSA (2.83 mM). TGF-β1 antibody on S-AuNP reduced extracellular TGF-β1 of cancer cells by 30%. Due to their efficacy and tunable properties, we anticipate numerous clinical applications of multifunctional gold nanospheres in treating breast cancer. PMID:27004512

  16. Automated beam placement for breast radiotherapy using a support vector machine based algorithm

    SciTech Connect

    Zhao Xuan; Kong, Dewen; Jozsef, Gabor; Chang, Jenghwa; Wong, Edward K.; Formenti, Silvia C.; Wang Yao

    2012-05-15

    Purpose: To develop an automated beam placement technique for whole breast radiotherapy using tangential beams. We seek to find optimal parameters for tangential beams to cover the whole ipsilateral breast (WB) and minimize the dose to the organs at risk (OARs). Methods: A support vector machine (SVM) based method is proposed to determine the optimal posterior plane of the tangential beams. Relative significances of including/avoiding the volumes of interests are incorporated into the cost function of the SVM. After finding the optimal 3-D plane that separates the whole breast (WB) and the included clinical target volumes (CTVs) from the OARs, the gantry angle, collimator angle, and posterior jaw size of the tangential beams are derived from the separating plane equation. Dosimetric measures of the treatment plans determined by the automated method are compared with those obtained by applying manual beam placement by the physicians. The method can be further extended to use multileaf collimator (MLC) blocking by optimizing posterior MLC positions. Results: The plans for 36 patients (23 prone- and 13 supine-treated) with left breast cancer were analyzed. Our algorithm reduced the volume of the heart that receives >500 cGy dose (V5) from 2.7 to 1.7 cm{sup 3} (p = 0.058) on average and the volume of the ipsilateral lung that receives >1000 cGy dose (V10) from 55.2 to 40.7 cm{sup 3} (p = 0.0013). The dose coverage as measured by volume receiving >95% of the prescription dose (V95%) of the WB without a 5 mm superficial layer decreases by only 0.74% (p = 0.0002) and the V95% for the tumor bed with 1.5 cm margin remains unchanged. Conclusions: This study has demonstrated the feasibility of using a SVM-based algorithm to determine optimal beam placement without a physician's intervention. The proposed method reduced the dose to OARs, especially for supine treated patients, without any relevant degradation of dose homogeneity and coverage in general.

  17. Map of Moessbauer Placement

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This elevation map of a soil target called 'Peak' was created from images taken by the microscopic imager located on the Mars Exploration Rover Spirit's instrument deployment device or 'arm.' The image reveals the various high and low points of this spot of soil after the Moessbauer spectrometer, another instrument on the rover's arm, was gently placed down on it. The blue areas are farthest away from the instrument; the red areas are closest. The variation in distance between blue and red areas is only 2 millimeters, or .08 of an inch. The images were acquired on sol 39 (February 11, 2004).

  18. A novel topical targeting system of caffeine microemulsion for inhibiting UVB-induced skin tumor: characterization, optimization, and evaluation.

    PubMed

    Ma, Huixian; Yu, Meng; Lei, Mingzhu; Tan, Fengping; Li, Nan

    2015-08-01

    The purpose of the present study was to develop an optimal microemulsion (ME) formulation as topical nanocarrier of caffeine (CAF) to enhance CAF skin retention and subsequently improve its therapeutic effect on UVB-induced skin carcinogenesis. The pseudo-ternary phase diagram was developed composing of Labrafil M 1944 CS as oil phase, Cremophor EL as surfactant, tetraglycol as cosurfactant, and water. Four ME formulations at water content of 50, 60, 70, and 80% were prepared along the water dilution line of oil to surfactant ratio of 1:3 and characterized in terms of morphology, droplet size, and electric conductivity. A gel at the same drug loads (1%, w/w) was used as control. Ex vivo skin permeation studies were conducted for ME optimization. The optimized formulation (ME4) was composed of 5% (w/w) Labrafil M 1944 CS, 15% (w/w) Smix (2/1, Cremophor EL and tetraglycol), and 80% (w/w) aqueous phase. The skin location amount of CAF from ME4 was nearly 3-fold higher than control (P < 0.05) with improved permeated amount through the skin. The skin targeting localization of hydrophilic substance from ME4 was further visualized through fluorescent-labeled ME by a confocal laser scanning microscope. In pharmacodynamics studies, CAF-loaded ME4 was superior in terms of increasing apoptotic sunburn cells (P < 0.05) as compared with control. Overall results suggested that the ME4 might be a promising vehicle for the topical delivery of CAF. PMID:25591953

  19. Automatic sensor placement for model-based robot vision.

    PubMed

    Chen, S Y; Li, Y F

    2004-02-01

    This paper presents a method for automatic sensor placement for model-based robot vision. In such a vision system, the sensor often needs to be moved from one pose to another around the object to observe all features of interest. This allows multiple three-dimensional (3-D) images to be taken from different vantage viewpoints. The task involves determination of the optimal sensor placements and a shortest path through these viewpoints. During the sensor planning, object features are resampled as individual points attached with surface normals. The optimal sensor placement graph is achieved by a genetic algorithm in which a min-max criterion is used for the evaluation. A shortest path is determined by Christofides algorithm. A Viewpoint Planner is developed to generate the sensor placement plan. It includes many functions, such as 3-D animation of the object geometry, sensor specification, initialization of the viewpoint number and their distribution, viewpoint evolution, shortest path computation, scene simulation of a specific viewpoint, parameter amendment. Experiments are also carried out on a real robot vision system to demonstrate the effectiveness of the proposed method. PMID:15369081

  20. Novel Bispecific PSMA/GRPr Targeting Radioligands with Optimized Pharmacokinetics for Improved PET Imaging of Prostate Cancer.

    PubMed

    Liolios, C; Schäfer, M; Haberkorn, U; Eder, M; Kopka, K

    2016-03-16

    A new series of bispecific radioligands (BRLs) targeting prostate-specific membrane antigen (PSMA) and gastrin releasing peptide receptor (GRPr), both expressed on prostate cancer cells, was developed. Their design was based on the bombesin (BN) analogue, H2N-PEG2-[d-Tyr(6),β-Ala(11),Thi(13),Nle(14)]BN(6-14), which binds to GRPr with high affinity and specificity, and the peptidomimetic urea-based pseudoirreversible inhibitor of PSMA, Glu-ureido-Lys. The two pharmacophores were coupled through copper(I)-catalyzed azide-alkyne cycloaddition to the bis(tetrafluorophenyl) ester of the chelating agent HBED-CC via amino acid linkers made of positively charged His (H) and negatively charged Glu (E): -(HE)n- (n = 0-3). The BRLs were labeled with (68)Ga, and their preliminary pharmacological properties were evaluated in vitro (competitive and time kinetic binding assays) on prostate cancer (PC-3, LNCaP) and rat pancreatic (AR42J) cell lines and in vivo by biodistribution and small animal PET imaging studies in both normal and tumor-bearing mice. The IC50/Ki values determined for all BRLs essentially matched those of the respective monomers. The maximal cellular uptake of the BLRs was observed between 20 and 30 min. The BRLs showed a synergistic ability in vivo by targeting both PSMA (LNCaP) and GRPr (PC-3) positive tumors, whereas the charged -(HE)n- (n = 1-3) linkers significantly reduced the kidney and spleen uptake. The bispecific (PSMA and GRPr) targeting ability and optimized pharmacokinetics of the compounds developed in this study could lead to their future application in clinical practice as more sensitive radiotracers for noninvasive imaging of prostate cancer (PCa) by PET/CT and PET/MRI. PMID:26726823

  1. Planning Motions and Placements for Virtual Demonstrators.

    PubMed

    Huang, Yazhou; Kallmann, Marcelo

    2016-05-01

    In order to deliver information effectively, virtual human demonstrators must be able to address complex spatial constraints and at the same time replicate motion coordination patterns observed in human-human interactions. We introduce in this paper a whole-body motion planning and synthesis framework that coordinates locomotion, body positioning, action execution and gaze behavior for generic demonstration tasks among obstacles. Human-like solutions are achieved with a coordination model extracted from experiments with human subjects. Given an observer location and a target demonstration to be performed, the proposed planner automatically identifies body placements respecting visibility constraints, locomotion accessibility, and action feasibility among obstacles. Actions are modeled with clusters of example motions and a fast collision avoidance procedure in blending space is introduced to avoid nearby obstacles when needed. Locomotion towards new placements integrates planning among obstacles and is based on a motion capture database organized for efficient synthesis of motions with precise path following and arrival constraints. The proposed solution introduces effective approaches for modeling and solving complex demonstrative tasks for interactive applications. PMID:27045912

  2. Advanced Placement: Access Not Exclusion.

    ERIC Educational Resources Information Center

    Camara, Wayne; Dorans, Neil J.; Morgan, Rick; Myford, Carol

    2000-01-01

    Refutes the assertion by W. Lichten (2000) that increased access to advanced placement (AP) courses in high school has led to a decline in AP quality. Suggests that increased access exposes students to college-level course material, encourages teachers to expand their knowledge domains, increases curriculum rigor, and give students new challenges.…

  3. Advanced Placement Course Description. Statistics.

    ERIC Educational Resources Information Center

    College Entrance Examination Board, New York, NY.

    The Advanced Placement (AP) program is a cooperative educational effort of secondary schools, colleges, and the College Board that consists of 30 college-level courses and examinations in 17 academic disciplines for highly motivated students in secondary schools. AP courses are offered in more than 11,000 high schools and are recognized by nearly…

  4. The Placement Professional as Marketeer.

    ERIC Educational Resources Information Center

    Walz, Garry R.

    1988-01-01

    Discusses resistance of helping professions to marketing. Defines human services marketing. Describes forces that are placing human services in an increasingly competitive position. Makes recommendations to enhance the image of career planning and placement services and increase their usage. Concludes that by adopting a marketeer orientation,…

  5. When Placement People Are Displaced.

    ERIC Educational Resources Information Center

    Ehrlich, Marianne

    1991-01-01

    Describes the experiences and insights of five laid-off placement people who discover the trauma of job loss. Discusses grieving a job loss, the emotions involved, the challenge of finding a new job, guilt faced by survivors, and advice to colleagues. (NB)

  6. Automatic sensor placement

    NASA Astrophysics Data System (ADS)

    Abidi, Besma R.

    1995-10-01

    Active sensing is the process of exploring the environment using multiple views of a scene captured by sensors from different points in space under different sensor settings. Applications of active sensing are numerous and can be found in the medical field (limb reconstruction), in archeology (bone mapping), in the movie and advertisement industry (computer simulation and graphics), in manufacturing (quality control), as well as in the environmental industry (mapping of nuclear dump sites). In this work, the focus is on the use of a single vision sensor (camera) to perform the volumetric modeling of an unknown object in an entirely autonomous fashion. The camera moves to acquire the necessary information in two ways: (a) viewing closely each local feature of interest using 2D data; and (b) acquiring global information about the environment via 3D sensor locations and orientations. A single object is presented to the camera and an initial arbitrary image is acquired. A 2D optimization process is developed. It brings the object in the field of view of the camera, normalizes it by centering the data in the image plane, aligns the principal axis with one of the camera's axes (arbitrarily chosen), and finally maximizes its resolution for better feature extraction. The enhanced image at each step is projected along the corresponding viewing direction. The new projection is intersected with previously obtained projections for volume reconstruction. During the global exploration of the scene, the current image as well as previous images are used to maximize the information in terms of shape irregularity as well as contrast variations. The scene on the borders of occlusion (contours) is modeled by an entropy-based objective functional. This functional is optimized to determine the best next view, which is recovered by computing the pose of the camera. A criterion based on the minimization of the difference between consecutive volume updates is set for termination of the

  7. Optimal scale-free searching strategies for the location of moving targets: New insights on visually cued mate location behaviour in insects

    NASA Astrophysics Data System (ADS)

    Reynolds, A. M.

    2006-12-01

    The most efficient random Lévy-flight (scale-free) searching strategies for the location of moving targets are identified. Brownian targets are best caught using ballistic (long straight-line) searches, and vice versa. Brownian searches and ballistic searches are close to being optimal for the capture of a Lévy-flyer whose flight-segment lengths are distributed according to an inverse-square law. The movement patterns of some foragers are characterised by such an inverse-square law and these are known to constitute an optimal searching strategy for the location of randomly and sparsely distributed stationary resources. It is suggested that visually cued mate location behaviour in butterflies and in some other insects can be understood within the context of optimal scale-free searching strategies for the location of moving targets.

  8. Camera placement in integer lattices (extended abstract)

    NASA Astrophysics Data System (ADS)

    Pocchiola, Michel; Kranakis, Evangelos

    1990-09-01

    Techniques for studying an art gallery problem (the camera placement problem) in the infinite lattice (L sup d) of d tuples of integers are considered. A lattice point A is visible from a camera C positioned at a vertex of (L sup d) if A does not equal C and if the line segment joining A and C crosses no other lattice vertex. By using a combination of probabilistic, combinatorial optimization and algorithmic techniques the position they must occupy in the lattice (L sup d) in the order to maximize their visibility can be determined in polynomial time, for any given number s less than or equal to (5 sup d) of cameras. This improves previous results for s less than or equal to (3 sup d).

  9. Advanced Placement: More than a Test.

    ERIC Educational Resources Information Center

    Colwell, Richard

    1990-01-01

    Encourages music teachers to work with students interested in advanced placement (AP) music courses. Discusses the logistics and advantages of placing students in these courses. Describes the Advanced Placement Listening and Literature and the Advanced Placement Theory courses and examinations. Outlines the examination scoring method and looks at…

  10. 34 CFR 300.104 - Residential placement

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 2 2010-07-01 2010-07-01 false Residential placement 300.104 Section 300.104 Education... DISABILITIES State Eligibility Other Fape Requirements § 300.104 Residential placement If placement in a public or private residential program is necessary to provide special education and related services to...

  11. 34 CFR 300.104 - Residential placement

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 34 Education 2 2011-07-01 2010-07-01 true Residential placement 300.104 Section 300.104 Education... DISABILITIES State Eligibility Other Fape Requirements § 300.104 Residential placement If placement in a public or private residential program is necessary to provide special education and related services to...

  12. Mathematics Placement at the University of Illinois

    ERIC Educational Resources Information Center

    Ahlgren Reddy, Alison; Harper, Marc

    2013-01-01

    Data from the ALEKS-based placement program at the University of Illinois is presented visually in several ways. The placement exam (an ALEKS assessment) contains precise item-specific information and the data show many interesting properties of the student populations of the placement courses, which include Precalculus, Calculus, and Business…

  13. 28 CFR 551.24 - Child placement.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 28 Judicial Administration 2 2012-07-01 2012-07-01 false Child placement. 551.24 Section 551.24... Birth Control, Pregnancy, Child Placement, and Abortion § 551.24 Child placement. (a) The Warden may not permit the inmate's new born child to return to the institution except in accordance with the Bureau...

  14. 28 CFR 551.24 - Child placement.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Child placement. 551.24 Section 551.24... Birth Control, Pregnancy, Child Placement, and Abortion § 551.24 Child placement. (a) The Warden may not permit the inmate's new born child to return to the institution except in accordance with the Bureau...

  15. 28 CFR 551.24 - Child placement.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 28 Judicial Administration 2 2013-07-01 2013-07-01 false Child placement. 551.24 Section 551.24... Birth Control, Pregnancy, Child Placement, and Abortion § 551.24 Child placement. (a) The Warden may not permit the inmate's new born child to return to the institution except in accordance with the Bureau...

  16. 28 CFR 551.24 - Child placement.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 28 Judicial Administration 2 2011-07-01 2011-07-01 false Child placement. 551.24 Section 551.24... Birth Control, Pregnancy, Child Placement, and Abortion § 551.24 Child placement. (a) The Warden may not permit the inmate's new born child to return to the institution except in accordance with the Bureau...

  17. 28 CFR 551.24 - Child placement.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 28 Judicial Administration 2 2014-07-01 2014-07-01 false Child placement. 551.24 Section 551.24... Birth Control, Pregnancy, Child Placement, and Abortion § 551.24 Child placement. (a) The Warden may not permit the inmate's new born child to return to the institution except in accordance with the Bureau...

  18. Can Placement Tests Inform Instructional Decisions?

    ERIC Educational Resources Information Center

    Green, Anthony B.; Weir, Cyril J.

    2004-01-01

    Studies of placement tests are typically narrowly concerned with their validation as instruments for the efficient grouping of students. They rarely explore the assumption that placement test content can be related to classroom tasks and so inform instructional decisions. This study focuses on a trial version of the Global Placement Test (GPT), a…

  19. A Client Centered Approach to Job Placement

    ERIC Educational Resources Information Center

    Salomone, Paul R.

    1971-01-01

    A client centered placement approach for handicapped people is proposed as an alternative to the traditional selective placement method. The client centered placement is based on client responsibility and counselor direction and requires the counselor to have an unrealistic but optimistic attitude that the client will get a suitable job.…

  20. Visual Illusions and the Control of Ball Placement in Goal-Directed Hitting

    ERIC Educational Resources Information Center

    Caljouw, Simone R.; Van der Kamp, John; Savelsbergh, Geert J. P.

    2010-01-01

    When hitting, kicking, or throwing balls at targets, online control in the target area is impossible. We assumed this lack of late corrections in the target area would induce an effect of a single-winged Muller-Lyer illusion on ball placement. After extensive practice in hitting balls to different landing locations, participants (N = 9) had to hit…

  1. Automatic Brachytherapy Seed Placement Under MRI Guidance

    PubMed Central

    Patriciu, Alexandru; Petrisor, Doru; Muntener, Michael; Mazilu, Dumitru; Schär, Michael; Stoianovici, Dan

    2011-01-01

    The paper presents a robotic method of performing low dose rate prostate brachytherapy under magnetic resonance imaging (MRI) guidance. The design and operation of a fully automated MR compatible seed injector is presented. This is used with the MrBot robot for transperineal percutaneous prostate access. A new image-registration marker and algorithms are also presented. The system is integrated and tested with a 3T MRI scanner. Tests compare three different registration methods, assess the precision of performing automated seed deployment, and use the seeds to assess the accuracy of needle targeting under image guidance. Under the ideal conditions of the in vitro experiments, results show outstanding image-guided needle and seed placement accuracy. PMID:17694871

  2. Critical Path-Based Thread Placement for NUMA Systems

    SciTech Connect

    Su, Chun-Yi; Li, Dong; Nikolopoulos, Dimitrios; Grove, Matthew; Cameron, Kirk W.; de Supinski, Bronis R.

    2012-01-01

    Multicore multiprocessors use Non Uniform Memory Architecture (NUMA) to improve their scalability. However,NUMA introduces performance penalties due to remote memory accesses. Without efficiently managing data layout and thread mapping to cores, scientific applications, even if they are optimized for NUMA, may suffer performance loss. In this paper, we present an algorithm that optimizes the placement of OpenMP threads on NUMA processors. By collecting information from hardware counters and defining new metrics to capture the effects of thread placement, the algorithm reduces NUMA performance penalty by minimizing the critical path of OpenMP parallel regions and by avoiding local memory resource contention. We evaluate our algorithm with NPB benchmarks and achieve performance improvement between 8.13% and 25.68%, compared to the OS default scheduling.

  3. Development and application of a channelized Hotelling observer for DBT optimization on structured background test images with mass simulating targets

    NASA Astrophysics Data System (ADS)

    Petrov, Dimitar; Michielsen, Koen; Cockmartin, Lesley; Zhang, Gouzhi; Young, Kenneth; Marshall, Nicholas; Bosmans, Hilde

    2016-03-01

    Digital breast tomosynthesis (DBT) is a 3D mammography technique that promises better visualization of low contrast lesions than conventional 2D mammography. A wide range of parameters influence the diagnostic information in DBT images and a systematic means of DBT system optimization is needed. The gold standard for image quality assessment is to perform a human observer experiment with experienced readers. Using human observers for optimization is time consuming and not feasible for the large parameter space of DBT. Our goal was to develop a model observer (MO) that can predict human reading performance for standard detection tasks of target objects within a structured phantom and subsequently apply it in a first comparative study. The phantom consists of an acrylic semi-cylindrical container with acrylic spheres of different sizes and the remaining space filled with water. Three types of lesions were included: 3D printed spiculated and non-spiculated mass lesions along with calcification groups. The images of the two mass lesion types were reconstructed with 3 different reconstruction methods (FBP, FBP with SRSAR, MLTRpr) and read by human readers. A Channelized Hotelling model observer was created for the non-spiculated lesion detection task using five Laguerre-Gauss channels, tuned for better performance. For the non-spiculated mass lesions a linear relation between the MO and human observer results was found, with correlation coefficients of 0.956 for standard FBP, 0.998 for FBP with SRSAR and 0.940 for MLTRpr. Both the MO and human observer percentage correct results for the spiculated masses were close to 100%, and showed no difference from each other for every reconstruction algorithm.

  4. Characterization and optimization of images acquired by a compact soft X-ray microscope based on a double stream gas-puff target source

    NASA Astrophysics Data System (ADS)

    Torrisi, A.; Wachulak, P.; Fahad Nawaz, M.; Bartnik, A.; Węgrzyński, L.; Jancarek, A.; Fiedorowicz, H.

    2016-04-01

    Using a table-top size soft X-ray (SXR) microscope, based on a laser plasma source with a double stream gas-puff target and a Fresnel zone plate objective, series of images of test samples were acquired. Characterization and optimization of the acquisition parameters were studied and evaluated in terms of signal to noise ratio (SNR). Conclusions for the optimization of SXR imaging were reached. Similar SNR measurements might be performed to characterize other SXR imaging systems as well. Software enabling live calculation of the SNR during the image acquisition might be introduced in future in the compact imaging systems for optimal image acquisition or for benchmarking purposes.

  5. Targeted thrombolysis of tissue plasminogen activator and streptokinase with extracellular biosynthesis nanoparticles using optimized Streptococcus equi supernatant.

    PubMed

    Tadayon, Ateke; Jamshidi, Reza; Esmaeili, Akbar

    2016-03-30

    Extracellular biosynthesis of nanoparticles have many important advantages such as well dispersed in aqueous solutions, low energy requirements, ecofriendly, non-toxic, low-costs and non-flocculate. This technique have shown significant promise as targeted drug delivery applications. In this investigation, for the first time, we examine the efficacy of targeted therapeutic delivery with t-PA and SK immobilized to biosynthesis of nanoparticles (CuNP) by using Streptococcus equi strains isolated from the horses of Iran and their ability to produce metallic nanoparticles. Also we compared them with their chemical synthesis. The S. equi was screened for its ability to produce MNPs. The minimum size and shapes (23-89 nm) are presented in the formation with good dispersion and high stability. Response Surface methodology was applied for the optimized production of biological CuNPs. The growth factors like pH, temperature and incubation time was changed. The optimum conditions to obtain CuNPs were found with the culture conditions of pH 7.5 in 120 h at 35 °C. To determine some of MNPs structural properties UV-vis absorption spectrophotometer, FTIR, XRD and SEM has characterized. The results provided some parameters may impact on the formation of biological MNPs. Lastly, these MNPs were conjugated with t-PA and SK, as a drug carrier. In addition, effective thrombolysis with magnet-guided SiO2CuNPs-tPA-SK is demonstrated in rat embolism model where 18.6% of the regular t-PA dose and 15.78% of SK dose restored and 15-25 min reductions in blood clot lysis time were observed compared with runs with free t-PA and without magnet-guided and using the same drug dosage. The comparison between CuNPs with MNPs shows that thrombolysis had not been directed to the type of magnetic carrier under the magnetic guide. PMID:26873394

  6. Optimal tumor shrinkage predicts long-term outcome in advanced nonsmall cell lung cancer (NSCLC) treated with target therapy

    PubMed Central

    He, Xiaobo; Zhang, Yang; Ma, Yuxiang; Zhou, Ting; Zhang, Jianwei; Hong, Shaodong; Sheng, Jin; Zhang, Zhonghan; Yang, Yunpeng; Huang, Yan; Zhang, Li; Zhao, Hongyun

    2016-01-01

    Abstract Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are used as standard therapies for advanced nonsmall cell lung cancer (NSCLC) patients with EGFR mutation positive. Because these targeted therapies could cause tumor necrosis and shrinkage, the purpose of the study is to search for a value of optimal tumor shrinkage as an appropriate indicator of outcome for advanced NSCLC. A total of 88 NSCLC enrollees of 3 clinical trials (IRESSA registration clinical trial, TRUST study and ZD6474 study), who received Gefitinib (250 mg, QD), Erlotinib (150 mg, QD), and ZD6474 (100 mg, QD), respectively, during December 2003 and October 2007, were retrospectively analyzed. The response evaluation criteria in solid tumors (RECIST) were used to identify responders, who had complete response (CR) or partial responses (PR) and nonresponders who had stable disease (SD) or progressive disease (PD). Receiver operating characteristics (ROC) analysis was used to find the optimal tumor shrinkage as an indicator for tumor therapeutic outcome. Univariate and multivariate Cox regression analyses were performed to compare the progression-free survival (PFS) and overall survival (OS) between responders and nonresponders stratified based on radiologic criteria. Among the 88 NSCLC patients, 26 were responders and 62 were nonresponders based on RECIST 1.0. ROC indicated that 8.32% tumor diameter shrinkage in the sum of the longest tumor diameter (SLD) was the cutoff point of tumor shrinkage outcomes, resulting in 46 responders (≤8.32%) and 42 nonresponders (≥8.32%). Univariate and multivariate Cox regression analyses indicated that (1) the responders (≤8.32%) and nonresponders (≥ −8.32%) were significantly different in median PFS (13.40 vs 1.17 months, P < 0.001) and OS (19.80 vs 7.90 months, P < 0.001) and (2) –8.32% in SLD could be used as the optimal threshold for PFS (hazard ratio [HR], 8.11, 95% CI, 3.75 to 17.51, P < 0.001) and OS

  7. The placement of equipment in the Space Station Freedom using constraint based reasoning

    NASA Technical Reports Server (NTRS)

    Tanner, Steve; Fennel, Randy

    1991-01-01

    This paper describes the Rack Equipment Placement and Optimization System. The primary objective of this system is to assist engineers with the placement of equipment into the racks of the modules of Space Station Freedom. It accomplishes this by showing a user where equipment placement is possible and by generating potential layouts. The system uses an explicit representation of integration constraints to search for potential solutions for individual rack equipment items. A simulated annealing process is being evaluated for total solution generation as well. Versions of this system are in use now and are assisting with the development of the Space Station Freedom at the Marshall Space Flight Center in Huntsville, Alabama.

  8. Intranasal Piperine-Loaded Chitosan Nanoparticles as Brain-Targeted Therapy in Alzheimer's Disease: Optimization, Biological Efficacy, and Potential Toxicity.

    PubMed

    Elnaggar, Yosra S R; Etman, Samar M; Abdelmonsif, Doaa A; Abdallah, Ossama Y

    2015-10-01

    Piperine (PIP) is a phytopharmaceutical with reported neuroprotective potential in Alzheimer's disease (AD). Oral PIP delivery suffers from its hydrophobicity and pre-systemic metabolism. In this article, mono-disperse intranasal chitosan nanoparticles (CS-NPs) were elaborated for brain targeting of PIP. Formula optimization was based on particle size (PS), zeta potential (ZP), polydispersity index (PDI), % entrapment efficiency (% EE), release studies, and transmission electron microscopy. AD was induced in 48 male Wistar rats on which full behavioral and biochemical testing was conducted. Brain toxicity was assessed based on Caspase-3 assay for apoptosis and tumor necrosis factor for inflammation. Spherical NPs with optimum % EE (81.70), PS (248.50 nm), PDI (0.24), and ZP (+56.30 mV) were elaborated. PIP-NPs could significantly improve cognitive functions as efficient as standard drug (donpezil injection) with additional advantages of dual mechanism (Ach esterase inhibition and antioxidant effect). CS-NPs could significantly alleviate PIP nasal irritation and showed no brain toxicity. This work was the first to report additional mechanism of PIP in AD via anti-apoptosis and anti-inflammatory effects. To conclude, mucoadhesive CS-NPs were successfully tailored for effective, safe, and non-invasive PIP delivery with 20-folds decrease in oral dose, opening a gate for a future with lower AD morbidity. PMID:26147711

  9. Family ties and child placement.

    PubMed

    Colón, F

    1978-09-01

    The fundamental premise of this paper is the primacy of the child's experience of biological-familial continuity in establishing his sense of self and personal significance. This paper examines the effects of current child placement practices on the child's ties to his biological, foster, and adoptive families. It explores alternative practices that would take into account biological-familial continuity. Comment is invited. PMID:744218

  10. 3D sensor placement strategy using the full-range pheromone ant colony system

    NASA Astrophysics Data System (ADS)

    Shuo, Feng; Jingqing, Jia

    2016-07-01

    An optimized sensor placement strategy will be extremely beneficial to ensure the safety and cost reduction considerations of structural health monitoring (SHM) systems. The sensors must be placed such that important dynamic information is obtained and the number of sensors is minimized. The practice is to select individual sensor directions by several 1D sensor methods and the triaxial sensors are placed in these directions for monitoring. However, this may lead to non-optimal placement of many triaxial sensors. In this paper, a new method, called FRPACS, is proposed based on the ant colony system (ACS) to solve the optimal placement of triaxial sensors. The triaxial sensors are placed as single units in an optimal fashion. And then the new method is compared with other algorithms using Dalian North Bridge. The computational precision and iteration efficiency of the FRPACS has been greatly improved compared with the original ACS and EFI method.

  11. Computerized planning of cryosurgery: from model reconstruction to cryoprobe placement strategies

    NASA Astrophysics Data System (ADS)

    Rabin, Yoed

    2009-02-01

    As a part of an ongoing program to develop computerized tools for surgery, the current study focuses on the design of optimal cryoprobe layouts for prostate cryosurgery. Once a decision to treat the prostate with cryosurgery has been made, its application can be presented as a four-stage process: (i) 3D reconstruction of the target region; (ii) evaluation of the optimum number of cryoprobes and their layout; (iii) insertion of cryoprobes according to that plan; and, (iv) orchestrating cryoprobe operation to achieve the optimum match between the target region and the forming frozen region. Cryosurgical success equals the sum of the successes of each of the above stages. To date, this four-stage process is performed manually, relying upon the cryosurgeon's experience and "rules of thumb". This manuscript reviews recent efforts to develop the necessary building blocks for an integrated computerized surgical tool for prostate cryosurgery, which includes methods for prostate model reconstruction, schemes for bioheat transfer simulation, and optimization techniques for cryoprobe placement; experimental verification of these building blocks are also presented. The emphasis in this line of development is on performing a full-scale planning in less than one minute, while the patient is on the operation table. It can be concluded from the current manuscript that the above goals are achievable. The current manuscript concludes with a review of current challenges in the development of related computerized means.

  12. Multiple objective optimization for active sensor management

    NASA Astrophysics Data System (ADS)

    Page, Scott F.; Dolia, Alexander N.; Harris, Chris J.; White, Neil M.

    2005-03-01

    The performance of a multi-sensor data fusion system is inherently constrained by the configuration of the given sensor suite. Intelligent or adaptive control of sensor resources has been shown to offer improved fusion performance in many applications. Common approaches to sensor management select sensor observation tasks that are optimal in terms of a measure of information. However, optimising for information alone is inherently sub-optimal as it does not take account of any other system requirements such as stealth or sensor power conservation. We discuss the issues relating to developing a suite of performance metrics for optimising multi-sensor systems and propose some candidate metrics. In addition it may not always be necessary to maximize information gain, in some cases small increases in information gain may take place at the cost of large sensor resource requirements. Additionally, the problems of sensor tasking and placement are usually treated separately, leading to a lack of coherency between sensor management frameworks. We propose a novel approach based on a high level decentralized information-theoretic sensor management architecture that unifies the processes of sensor tasking and sensor placement into a single framework. Sensors are controlled using a minimax multiple objective optimisation approach in order to address probability of target detection, sensor power consumption, and sensor survivability whilst maintaining a target estimation covariance threshold. We demonstrate the potential of the approach through simulation of a multi-sensor, target tracking scenario and compare the results with a single objective information based approach.

  13. Defining the Optimal Planning Target Volume in Image-Guided Stereotactic Radiosurgery of Brain Metastases: Results of a Randomized Trial

    SciTech Connect

    Kirkpatrick, John P.; Wang, Zhiheng; Sampson, John H.; McSherry, Frances; Herndon, James E.; Allen, Karen J.; Duffy, Eileen; Hoang, Jenny K.; Chang, Zheng; Yoo, David S.; Kelsey, Chris R.; Yin, Fang-Fang

    2015-01-01

    Purpose: To identify an optimal margin about the gross target volume (GTV) for stereotactic radiosurgery (SRS) of brain metastases, minimizing toxicity and local recurrence. Methods and Materials: Adult patients with 1 to 3 brain metastases less than 4 cm in greatest dimension, no previous brain radiation therapy, and Karnofsky performance status (KPS) above 70 were eligible for this institutional review board–approved trial. Individual lesions were randomized to 1- or 3- mm uniform expansion of the GTV defined on contrast-enhanced magnetic resonance imaging (MRI). The resulting planning target volume (PTV) was treated to 24, 18, or 15 Gy marginal dose for maximum PTV diameters less than 2, 2 to 2.9, and 3 to 3.9 cm, respectively, using a linear accelerator–based image-guided system. The primary endpoint was local recurrence (LR). Secondary endpoints included neurocognition Mini-Mental State Examination, Trail Making Test Parts A and B, quality of life (Functional Assessment of Cancer Therapy-Brain), radionecrosis (RN), need for salvage radiation therapy, distant failure (DF) in the brain, and overall survival (OS). Results: Between February 2010 and November 2012, 49 patients with 80 brain metastases were treated. The median age was 61 years, the median KPS was 90, and the predominant histologies were non–small cell lung cancer (25 patients) and melanoma (8). Fifty-five, 19, and 6 lesions were treated to 24, 18, and 15 Gy, respectively. The PTV/GTV ratio, volume receiving 12 Gy or more, and minimum dose to PTV were significantly higher in the 3-mm group (all P<.01), and GTV was similar (P=.76). At a median follow-up time of 32.2 months, 11 patients were alive, with median OS 10.6 months. LR was observed in only 3 lesions (2 in the 1 mm group, P=.51), with 6.7% LR 12 months after SRS. Biopsy-proven RN alone was observed in 6 lesions (5 in the 3-mm group, P=.10). The 12-month DF rate was 45.7%. Three months after SRS, no significant change in

  14. Performance of a parallel algorithm for standard cell placement on the Intel Hypercube

    NASA Technical Reports Server (NTRS)

    Jones, Mark; Banerjee, Prithviraj

    1987-01-01

    A parallel simulated annealing algorithm for standard cell placement that is targeted to run on the Intel Hypercube is presented. A tree broadcasting strategy that is used extensively in our algorithm for updating cell locations in the parallel environment is presented. Studies on the performance of our algorithm on example industrial circuits show that it is faster and gives better final placement results than the uniprocessor simulated annealing algorithms.

  15. Stereotactic Bony Trajectory Preservation for Responsive Neurostimulator Lead Placement Following Depth EEG Recording

    PubMed Central

    Halpern, Casey H

    2016-01-01

    Responsive neurostimulation (RNS) is rapidly gaining traction as a therapy for medically refractory epilepsy. Depth electrode placement for stimulation of a deep seizure focus may be indicated after the focus has been electrophysiologically localized using depth electroencephalography (depth EEG). We describe a simple technique whereby the bony trajectories created during initial stereotactic placement of depth EEG electrodes are preserved and reused for RNS with depth electrodes. This technique may help to improve targeting and maximize surgical efficiency. PMID:27158578

  16. Stereotactic Bony Trajectory Preservation for Responsive Neurostimulator Lead Placement Following Depth EEG Recording.

    PubMed

    Miller, Kai; Halpern, Casey H

    2016-01-01

    Responsive neurostimulation (RNS) is rapidly gaining traction as a therapy for medically refractory epilepsy. Depth electrode placement for stimulation of a deep seizure focus may be indicated after the focus has been electrophysiologically localized using depth electroencephalography (depth EEG). We describe a simple technique whereby the bony trajectories created during initial stereotactic placement of depth EEG electrodes are preserved and reused for RNS with depth electrodes. This technique may help to improve targeting and maximize surgical efficiency. PMID:27158578

  17. Final Report on Development of Optimized Field-Reversed Configuration Plasma Formation Techniques for Magnetized Target Fusion

    SciTech Connect

    Lynn, Alan

    2013-11-01

    The University of New Mexico (UNM) proposed a collaboration with Los Alamos National Laboratory (LANL) to develop and test methods for improved formation of field-reversed configuration (FRC) plasmas relevant to magnetized target fusion (MTF) energy research. MTF is an innovative approach for a relatively fast and cheap path to the production of fusion energy that utilizes magnetic confinement to assist in the compression of a hot plasma to thermonuclear conditions by an external driver. LANL is currently pursing demonstration of the MTF concept via compression of an FRC plasma by a metal liner z-pinch in conjunction with the Air Force Research Laboratory in Albuquerque, NM. A key physics issue for the FRC's ultimate success as an MTF target lies in the initial pre-ionization (PI) stage. The PI plasma sets the initial conditions from which the FRC is created. In particular, the PI formation process determines the amount of magnetic flux that can be trapped to form the FRC. A ringing theta pinch ionization (RTPI) technique, such as currently used by the FRX-L device at LANL, has the advantages of high ionization fraction, simplicity (since no additional coils are required), and does not require internal electrodes which can introduce impurities into the plasma. However RTPI has been shown to only trap 50% of the initial bias flux at best and imposes additional engineering constraints on the capacitor banks. The amount of trapped flux plays an important role in the FRC's final equilibrium, transport, and stability properties, and provides increased ohmic heating of the FRC through induced currents as the magnetic field decays. Increasing the trapped flux also provides the route to greatest potential gains in FRC lifetime, which is essential to provide enough time to translate and compress the FRC effectively. In conjunction with LANL we initially planned to develop and test a microwave break- down system to improve the initial PI plasma formation. The UNM team would

  18. Military target task performance after wavefront-guided (WFG) and wavefront-optimized (WFO) photorefractive keratectomy (PRK)

    NASA Astrophysics Data System (ADS)

    Maurer, Tana; Deaver, Dawne; Howell, Christopher; Moyer, Steve; Nguyen, Oanh; Mueller, Greg; Ryan, Denise; Sia, Rose K.; Stutzman, Richard; Pasternak, Joseph; Bower, Kraig

    2014-06-01

    Major decisions regarding life and death are routinely made on the modern battlefield, where visual function of the individual soldier can be of critical importance in the decision-making process. Glasses in the combat environment have considerable disadvantages: degradation of short term visual performance can occur as dust and sweat accumulate on lenses during a mission or patrol; long term visual performance can diminish as lenses become increasingly scratched and pitted; during periods of intense physical trauma, glasses can be knocked off the soldier's face and lost or broken. Although refractive surgery offers certain benefits on the battlefield when compared to wearing glasses, it is not without potential disadvantages. As a byproduct of refractive surgery, elevated optical aberrations can be induced, causing decreases in contrast sensitivity and increases in the symptoms of glare, halos, and starbursts. Typically, these symptoms occur under low light level conditions, the same conditions under which most military operations are initiated. With the advent of wavefront aberrometry, we are now seeing correction not only of myopia and astigmatism but of other, smaller optical aberrations that can cause the above symptoms. In collaboration with the Warfighter Refractive Eye Surgery Program and Research Center (WRESP-RC) at Fort Belvoir and Walter Reed National Military Medical Center (WRNMMC), the overall objective of this study is to determine the impact of wavefront guided (WFG) versus wavefront-optimized (WFO) photorefractive keratectomy (PRK) on military task visual performance. Psychophysical perception testing was conducted before and after surgery to measure each participant's performance regarding target detection and identification using thermal imagery. The results are presented here.

  19. Targeting mitochondrial cardiolipin and the cytochrome c/cardiolipin complex to promote electron transport and optimize mitochondrial ATP synthesis

    PubMed Central

    Birk, A V; Chao, W M; Bracken, C; Warren, J D; Szeto, H H

    2014-01-01

    BACKGROUND AND PURPOSE Cardiolipin plays an important role in mitochondrial respiration and cardiolipin peroxidation is associated with age-related diseases. Hydrophobic interactions between cytochrome c and cardiolipin converts cytochrome c from an electron carrier to a peroxidase. In addition to cardiolipin peroxidation, this impedes electron flux and inhibits mitochondrial ATP synthesis. SS-31 (D-Arg-dimethylTyr-Lys-Phe-NH2) selectively binds to cardiolipin and inhibits cytochrome c peroxidase activity. Here, we examined whether SS-31 also protected the electron carrier function of cytochrome c. EXPERIMENTAL APPROACH Interactions of SS-31 with cardiolipin were studied using liposomes and bicelles containing phosphatidylcholine alone or with cardiolipin. Structural interactions were assessed by fluorescence spectroscopy, turbidity and nuclear magnetic resonance. Effects of cardiolipin on electron transfer kinetics of cytochrome c were determined by cytochrome c reduction in vitro and oxygen consumption using mitoplasts, frozen and fresh mitochondria. KEY RESULTS SS-31 interacted only with liposomes and bicelles containing cardiolipin in about 1:1 ratio. NMR studies demonstrated that the aromatic residues of SS-31 penetrated deep into cardiolipin-containing bilayers. SS-31 restored cytochrome c reduction and mitochondrial oxygen consumption in the presence of added cardiolipin. In fresh mitochondria, SS-31 increased state 3 respiration and efficiency of ATP synthesis. CONCLUSIONS AND IMPLICATIONS SS-31 selectively targeted cardiolipin and modulated its interaction with cytochrome c. SS-31 inhibited the cytochrome c/cardiolipin complex peroxidase activity while protecting its ability to serve as an electron carrier, thus optimizing mitochondrial electron transport and ATP synthesis. This novel class of cardiolipin therapeutics has the potential to restore mitochondrial bioenergetics for treatment of numerous age-related diseases. LINKED ARTICLES This article is

  20. Acadian flycatcher nest placement: Does placement influence reproductive success?

    USGS Publications Warehouse

    Wilson, R.R.; Cooper, R.J.

    1998-01-01

    We located 511 Acadian Flycatcher (Empidonax virescens) nests in bottomland hardwood forest of eastern Arkansas. Microhabitat characteristics were measured and their relationship with nest success evaluated. Fifty-two percent of all nesting attempts resulted in predation. Attributes of nest placement were similar between successful and unsuccessful nests, although successful nests were placed higher. Similarly, nonparasitized nests were typically higher than parasitized nests. Nests initiated late in the breeding season were placed in larger trees with higher canopy bases resulting in increased vegetation around the nest. Fifteen different tree species were used for nesting. Acadian Flycatchers chose nest trees in a nonrandom fashion, selecting Nuttall oak (Quercus nuttallii) and possumhaw (Ilex decidua) in greater proportions than their availability. However, there was no relationship between tree species used for nesting and nest success. Nest height was positively correlated with concealment at the nest site, supporting the predator-avoidance theory. No other attribute of nest placement differentiated successful nest sites, suggesting that nest predation is likely a function of random events in space and time.

  1. Pre- and post-operative management of dental implant placement. Part 1: management of post-operative pain.

    PubMed

    Bryce, G; Bomfim, D I; Bassi, G S

    2014-08-01

    Although dental implant placements have high success rates and a low incidence of morbidity, post-operative pain and complications with the healing process have been reported. There is little guidance available regarding optimal pre- and post-operative management of dental implant placement. This first paper discusses the mechanisms of pain associated with dental implant placement and offers guidance to clinicians on optimal pre- and post-operative pain management regimes. The second paper aims to discuss pre- and post-operative means of reducing the risk of early healing complications. PMID:25104691

  2. Peripheral Stent Placement in Hemodialysis Grafts

    SciTech Connect

    Kariya, Shuji Tanigawa, Noboru; Kojima, Hiroyuki; Komemushi, Atsushi; Shomura, Yuzo; Shiraishi, Tomokuni; Kawanaka, Toshiaki; Sawada, Satoshi

    2009-09-15

    The purpose of the present study was to evaluate the clinical outcome of peripheral stent placement after failed balloon angioplasty in patients with grafts who are on hemodialysis. We examined 30 Wallstents that were placed in 26 patients because balloon angioplasty failed or early restenosis (<3 months) occurred within 3 months. We retrospectively reviewed 267 consecutive balloon angioplasties performed in 71 patients with graft access between August 2000 and March 2007. Stent placements accounted for 30 (11.2%) of the 267 balloon angioplasties. The clinical success rate of stent placement was 93.3% (28 of 30 stent placements). The 3-, 6-, and 12-month primary patency rates were 73.3%, 39.3%, and 17.7%, respectively. The 1-, 2-, and 3-year secondary patency rates were 90.2%, 83.8%, and 83.8%, respectively. Primary patency was significantly prolonged by stent placement after early restenosis compared with previous balloon angioplasty alone (P = 0.0059). Primary patency after stent placement was significantly lower than after successful balloon angioplasty without indications for stent placement (P = 0.0279). Secondary patency rates did not significantly differ between stent placement and balloon angioplasty alone. The mean number of reinterventions required to maintain secondary patency after stent placement was significantly larger than that after balloon angioplasty alone (Mann-Whitney U test, P = 0.0419). We concluded that peripheral stent placement for graft access is effective for salvaging vascular access after failed balloon angioplasty and for prolonging patency in early restenosis after balloon angioplasty. However, reinterventions are required to maintain secondary patency after stent placement. Furthermore, peripheral stent placement for graft access cannot achieve the same primary patency as balloon angioplasty alone.

  3. Product placement of computer games in cyberspace.

    PubMed

    Yang, Heng-Li; Wang, Cheng-Shu

    2008-08-01

    Computer games are considered an emerging media and are even regarded as an advertising channel. By a three-phase experiment, this study investigated the advertising effectiveness of computer games for different product placement forms, product types, and their combinations. As the statistical results revealed, computer games are appropriate for placement advertising. Additionally, different product types and placement forms produced different advertising effectiveness. Optimum combinations of product types and placement forms existed. An advertisement design model is proposed for use in game design environments. Some suggestions are given for advertisers and game companies respectively. PMID:18721087

  4. Automated fiber placement: Evolution and current demonstrations

    NASA Technical Reports Server (NTRS)

    Grant, Carroll G.; Benson, Vernon M.

    1993-01-01

    The automated fiber placement process has been in development at Hercules since 1980. Fiber placement is being developed specifically for aircraft and other high performance structural applications. Several major milestones have been achieved during process development. These milestones are discussed in this paper. The automated fiber placement process is currently being demonstrated on the NASA ACT program. All demonstration projects to date have focused on fiber placement of transport aircraft fuselage structures. Hercules has worked closely with Boeing and Douglas on these demonstration projects. This paper gives a description of demonstration projects and results achieved.

  5. Adaptable Deployable Entry and Placement Technology (ADEPT)

    NASA Video Gallery

    The Adaptable, Deployable Entry Placement Technology (ADEPT) Project will test and demonstrate a deployable aeroshell concept as a viable thermal protection system for entry, descent, and landing o...

  6. Opening up placement opportunities for students.

    PubMed

    Hill, Phillipa; Bullpitt, Samantha; Dean, Sharon; O'Flanagan, Sheryl; Fishburn, Nicky

    Student nurses need a variety of high-quality practice placements to prepare them for qualification yet, in reality, this can be difficult to achieve. A practice placement allocation model has enabled one university and its partner healthcare organisations to shift from a traditional, process-led system to a robust, proactive, student-focused approach. The model is based on partnership concepts including advance planning of student placements and clear lines of communication. It has resulted in 100% of first-year students taking part in a new fundamentals of care placement and received positive feedback from students and mentors. PMID:26012012

  7. The damper placement problem for large flexible space structures

    NASA Technical Reports Server (NTRS)

    Kincaid, Rex K.

    1992-01-01

    The damper placement problem for large flexible space truss structures is formulated as a combinatorial optimization problem. The objective is to determine the p truss members of the structure to replace with active (or passive) dampers so that the modal damping ratio is as large as possible for all significant modes of vibration. Equivalently, given a strain energy matrix with rows indexed on the modes and the columns indexed on the truss members, we seek to find the set of p columns such that the smallest row sum, over the p columns, is maximized. We develop a tabu search heuristic for the damper placement problems on the Controls Structures Interaction (CSI) Phase 1 Evolutionary Model (10 modes and 1507 truss members). The resulting solutions are shown to be of high quality.

  8. Actuator placement in prestressed adaptive trusses for vibration control

    NASA Technical Reports Server (NTRS)

    Jalihal, P.; Utku, Senol; Wada, Ben K.

    1993-01-01

    This paper describes the optimal location selection of actuators for vibration control in prestressed adaptive trusses. Since prestressed adaptive trusses are statically indeterminate, the actuators to be used for vibration control purposes must work against (1) existing static axial prestressing forces, (2) static axial forces caused by the actuation, and (3) dynamic axial forces caused by the motion of the mass. In statically determinate adaptive trusses (1) and (2) are non - existing. The actuator placement problem in statically indeterminate trusses is therefore governed by the actuation energy and the actuator strength requirements. Assuming output feedback type control of selected vibration modes in autonomous systems, a procedure is given for the placement of vibration controlling actuators in prestressed adaptive trusses.

  9. Gel placement in fractured systems

    SciTech Connect

    Seright, R.S.

    1995-11-01

    This paper examines several factors that can have an important effect on gel placement in fractured systems, including gelant viscosity, degree of gelation, and gravity. For an effective gel treatment, the conductivity of the fracture must be reduced and a viable flow path must remain open between the wellbore and mobile oil in the reservoir. During placement, the gelant that``leaks off`` from the fracture into the rock plays an important role in determining how well a gel treatment will reduce channeling. For a given volume of gelant injected the distance of gelant leakoff is greater for a viscous gelant than for a low-viscosity gelant. In one method to minimize gelant leakoff, sufficient gelation is designed to occur before the gelant leaves the wellbore. The authors investigated this approach in numerous experiments with both fractured and unfractured cores. They studied Cr(III)/acetate/hydrolyzed polyacrylamide (HPAM), resorcinol/formaldehyde, Cr(III)/xanthan, aluminum/citrate/HPAM, and other gelants and gels with various delay times between gelant preparation and injection. Their results suggest both hope and caution concerning the injection of gels into fractured systems.

  10. Inhibition of Ebola Virus Infection: Identification of Niemann-Pick C1 as the Target by Optimization of a Chemical Probe

    PubMed Central

    2012-01-01

    A high-throughput screen identified adamantane dipeptide 1 as an inhibitor of Ebola virus (EboV) infection. Hit-to-lead optimization to determine the structure–activity relationship (SAR) identified the more potent EboV inhibitor 2 and a photoaffinity labeling agent 3. These antiviral compounds were employed to identify the target as Niemann-Pick C1 (NPC1), a host protein that binds the EboV glycoprotein and is essential for infection. These studies establish NPC1 as a promising target for antiviral therapy. PMID:23526644

  11. Model-based assessment of probe placement criteria in cancer therapy using RF ablation

    NASA Astrophysics Data System (ADS)

    Tanotogono, E. W.; Akasum, G. F.; Suprijanto; Sudirham, J. J.

    2016-03-01

    Radiofrequency ablation has been developed as a minimally-invasive method for cancer therapy. Nevertheless, the unfeasibility of direct observation during ablation process sometimes becomes a challenge for practitioners, particularly those constrained by the absence of a proper monitoring system. Thus, aiming to develop a prudent cancer therapy planning, this research develops a 3D model that enable practitioners to predict the tissue damage resulted by a simulated ablation before a real ablation is executed. The model, developed using finite element method, is made to mimic real human liver tissue by simulating its physical properties as temperature-dependent functions. Three probe placement cases, representing three different approaches, are analysed to study the effect of probe placement configuration on tissue damage formed during a time-dependent ablation process. The three placement cases are surface-perpendicular placement, misaligned placement, and relatively accurate placement. It can be concluded that the accuracy of a probe placement configuration can be assessed by quantifying two major parameters: average tissue damage in the target domain and accumulated damage resulted in complementary tissue domain. Optimum ablation duration can also be determined by considering those parameters.

  12. Ampicillin/penicillin-binding protein interactions as a model drug-target system to optimize affinity pull-down and mass spectrometric strategies for target and pathway identification.

    PubMed

    von Rechenberg, Moritz; Blake, Brian Kelly; Ho, Yew-Seng J; Zhen, Yuejun; Chepanoske, Cindy Lou; Richardson, Bonnie E; Xu, Nafei; Kery, Vladimir

    2005-05-01

    The identification and validation of the targets of active compounds identified in cell-based assays is an important step in preclinical drug development. New analytical approaches that combine drug affinity pull-down assays with mass spectrometry (MS) could lead to the identification of new targets and druggable pathways. In this work, we investigate a drug-target system consisting of ampicillin- and penicillin-binding proteins (PBPs) to evaluate and compare different amino-reactive resins for the immobilization of the affinity compound and mass spectrometric methods to identify proteins from drug affinity pull-down assays. First, ampicillin was immobilized onto various amino-reactive resins, which were compared in the ampicillin-PBP model with respect to their nonspecific binding of proteins from an Escherichia coli membrane extract. Dynal M-270 magnetic beads were chosen to further study the system as a model for capturing and identifying the targets of ampicillin, PBPs that were specifically and covalently bound to the immobilized ampicillin. The PBPs were identified, after in situ digestion of proteins bound to ampicillin directly on the beads, by using either one-dimensional (1-D) or two-dimensional (2-D) liquid chromatography (LC) separation techniques followed by tandem mass spectrometry (MS/MS) analysis. Alternatively, an elution with N-lauroylsarcosine (sarcosyl) from the ampicillin beads followed by in situ digestion and 2-D LC-MS/MS analysis identified proteins potentially interacting noncovalently with the PBPs or the ampicillin. The in situ approach required only little time, resources, and sample for the analysis. The combination of drug affinity pull-down assays with in situ digestion and 2-D LC-MS/MS analysis is a useful tool in obtaining complex information about a primary drug target as well as its protein interactors. PMID:15761956

  13. Optimization of acquisition parameters and accuracy of target motion trajectory for four-dimensional cone-beam computed tomography with a dynamic thorax phantom.

    PubMed

    Shimohigashi, Yoshinobu; Araki, Fujio; Maruyama, Masato; Nakaguchi, Yuji; Nakato, Kengo; Nagasue, Nozomu; Kai, Yudai

    2015-01-01

    Our purpose in this study was to evaluate the performance of four-dimensional computed tomography (4D-CBCT) and to optimize the acquisition parameters. We evaluated the relationship between the acquisition parameters of 4D-CBCT and the accuracy of the target motion trajectory using a dynamic thorax phantom. The target motion was created three dimensionally using target sizes of 2 and 3 cm, respiratory cycles of 4 and 8 s, and amplitudes of 1 and 2 cm. The 4D-CBCT data were acquired under two detector configurations: "small mode" and "medium mode". The projection data acquired with scan times ranging from 1 to 4 min were sorted into 2, 5, 10, and 15 phase bins. The accuracy of the measured target motion trajectories was evaluated by means of the root mean square error (RMSE) from the setup values. For the respiratory cycle of 4 s, the measured trajectories were within 2 mm of the setup values for all acquisition times and target sizes. Similarly, the errors for the respiratory cycle of 8 s were <4 mm. When we used 10 or more phase bins, the measured trajectory errors were within 2 mm of the setup values. The trajectory errors for the two detector configurations showed similar trends. The acquisition times for achieving an RMSE of 1 mm for target sizes of 2 and 3 cm were 2 and 1 min, respectively, for respiratory cycles of 4 s. The results obtained in this study enable optimization of the acquisition parameters for target size, respiratory cycle, and desired measurement accuracy. PMID:25287015

  14. Controllability analysis as a pre-selection method for sensor placement in water distribution systems.

    PubMed

    Diao, Kegong; Rauch, Wolfgang

    2013-10-15

    Detection of contamination events in water distribution systems is a crucial task for maintaining water security. Online monitoring is considered as the most cost-effective technology to protect against the impacts of contaminant intrusions. Optimization methods for sensor placement enable automated sensor layout design based on hydraulic and water quality simulation. However, this approach results in an excessive computational burden. In this paper we outline the application of controllability analysis as preprocessing method for sensor placement. Based on case studies we demonstrate that the method decreases the number of decision variables for subsequent optimization dramatically to app. 30 to 40 percent. PMID:23948563

  15. Treatment planning for prostate focal laser ablation in the face of needle placement uncertainty

    SciTech Connect

    Cepek, Jeremy Fenster, Aaron; Lindner, Uri; Trachtenberg, John; Davidson, Sean R. H.; Haider, Masoom A.; Ghai, Sangeet

    2014-01-15

    Purpose: To study the effect of needle placement uncertainty on the expected probability of achieving complete focal target destruction in focal laser ablation (FLA) of prostate cancer. Methods: Using a simplified model of prostate cancer focal target, and focal laser ablation region shapes, Monte Carlo simulations of needle placement error were performed to estimate the probability of completely ablating a region of target tissue. Results: Graphs of the probability of complete focal target ablation are presented over clinically relevant ranges of focal target sizes and shapes, ablation region sizes, and levels of needle placement uncertainty. In addition, a table is provided for estimating the maximum target size that is treatable. The results predict that targets whose length is at least 5 mm smaller than the diameter of each ablation region can be confidently ablated using, at most, four laser fibers if the standard deviation in each component of needle placement error is less than 3 mm. However, targets larger than this (i.e., near to or exceeding the diameter of each ablation region) require more careful planning. This process is facilitated by using the table provided. Conclusions: The probability of completely ablating a focal target using FLA is sensitive to the level of needle placement uncertainty, especially as the target length approaches and becomes greater than the diameter of ablated tissue that each individual laser fiber can achieve. The results of this work can be used to help determine individual patient eligibility for prostate FLA, to guide the planning of prostate FLA, and to quantify the clinical benefit of using advanced systems for accurate needle delivery for this treatment modality.

  16. Dosimetric Effects of Magnetic Resonance Imaging-assisted Radiotherapy Planning: Dose Optimization for Target Volumes at High Risk and Analytic Radiobiological Dose Evaluation.

    PubMed

    Park, Ji-Yeon; Suh, Tae Suk; Lee, Jeong-Woo; Ahn, Kook-Jin; Park, Hae-Jin; Choe, Bo-Young; Hong, Semie

    2015-10-01

    Based on the assumption that apparent diffusion coefficients (ADCs) define high-risk clinical target volume (aCTVHR) in high-grade glioma in a cellularity-dependent manner, the dosimetric effects of aCTVHR-targeted dose optimization were evaluated in two intensity-modulated radiation therapy (IMRT) plans. Diffusion-weighted magnetic resonance (MR) images and ADC maps were analyzed qualitatively and quantitatively to determine aCTVHR in a high-grade glioma with high cellularity. After confirming tumor malignancy using the average and minimum ADCs and ADC ratios, the aCTVHR with double- or triple-restricted water diffusion was defined on computed tomography images through image registration. Doses to the aCTVHR and CTV defined on T1-weighted MR images were optimized using a simultaneous integrated boost technique. The dosimetric benefits for CTVs and organs at risk (OARs) were compared using dose volume histograms and various biophysical indices in an ADC map-based IMRT (IMRTADC) plan and a conventional IMRT (IMRTconv) plan. The IMRTADC plan improved dose conformity up to 15 times, compared to the IMRTconv plan. It reduced the equivalent uniform doses in the visual system and brain stem by more than 10% and 16%, respectively. The ADC-based target differentiation and dose optimization may facilitate conformal dose distribution to the aCTVHR and OAR sparing in an IMRT plan. PMID:26425053

  17. 32 CFR 1656.10 - Job placement.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 6 2011-07-01 2011-07-01 false Job placement. 1656.10 Section 1656.10 National....10 Job placement. (a) Selective Service will maintain a job bank for the exclusive purpose of placing ASWs in alternative service jobs. (b) An ASW who has identified his own job in accordance with §...

  18. 32 CFR 1656.10 - Job placement.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 6 2012-07-01 2012-07-01 false Job placement. 1656.10 Section 1656.10 National....10 Job placement. (a) Selective Service will maintain a job bank for the exclusive purpose of placing ASWs in alternative service jobs. (b) An ASW who has identified his own job in accordance with §...

  19. 32 CFR 1656.10 - Job placement.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 6 2014-07-01 2014-07-01 false Job placement. 1656.10 Section 1656.10 National....10 Job placement. (a) Selective Service will maintain a job bank for the exclusive purpose of placing ASWs in alternative service jobs. (b) An ASW who has identified his own job in accordance with §...

  20. 32 CFR 1656.10 - Job placement.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 6 2013-07-01 2013-07-01 false Job placement. 1656.10 Section 1656.10 National....10 Job placement. (a) Selective Service will maintain a job bank for the exclusive purpose of placing ASWs in alternative service jobs. (b) An ASW who has identified his own job in accordance with §...

  1. 32 CFR 1656.10 - Job placement.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Job placement. 1656.10 Section 1656.10 National....10 Job placement. (a) Selective Service will maintain a job bank for the exclusive purpose of placing ASWs in alternative service jobs. (b) An ASW who has identified his own job in accordance with §...

  2. Exploring Continuous Clinical Placement for Undergraduate Students

    ERIC Educational Resources Information Center

    McKenna, Lisa G.; Wray, Natalie; McCall, Louise

    2009-01-01

    Clinical placements are integral to health professional preparatory courses. These placements allow for the application of classroom-based learning into real patient care situations. In doing so, they provide opportunities for applying theoretical knowledge into practice contexts, skills development and socialisation into the chosen profession.…

  3. Advanced Placement Courses and American Indian Performance

    ERIC Educational Resources Information Center

    Moore, George; Slate, John R.

    2010-01-01

    Enrollment in Advanced Placement (AP) courses and performance on Advanced Placement examinations for American Indians in the U.S. for 2007 was analyzed. Scores on AP examinations, overall and then for five AP courses, were compared to the AP examination scores of White students. In every case, American Indians had AP examination scores that were…

  4. Film Processing Module for Automated Fiber Placement

    NASA Technical Reports Server (NTRS)

    Hulcher, A. Bruce

    2004-01-01

    This viewgraph presentation describes fiber placement technology which was originally developed by Marshall Space Flight Center (MSFC) for the fabrication of fiber composite propellant tanks. The presentation includes an image of the MSFC Fiber Placement Machine, which is a prototype test bed, and images of some of the machine's parts. Some possible applications for the machines are listed.

  5. PASS--Placement/Advisement for Student Success.

    ERIC Educational Resources Information Center

    Shreve, Chuck; Wildie, Avace

    In 1985-86, Northern Michigan College (NMC) used funds received from the United States Department of Education to develop a system of assessment, advisement, and placement--Placement/Advisement for Student Success (PASS), an integrated system designed to improve student retention. PASS currently consists of three components: summer orientation,…

  6. Private Placement Debt Financing for Public Entities

    ERIC Educational Resources Information Center

    Holman, Lance S.

    2010-01-01

    Private placement financing is a debt or capital lease obligation arranged between a municipality or a 501(c) (3) not-for-profit organization and a single sophisticated institutional investor. The investor can be a bank, insurance company, finance company, hedge fund, or high-net worth individual. Private placement financing is similar to…

  7. Preceptor Handbook: Rural Clinical Nurse Placement Center.

    ERIC Educational Resources Information Center

    Stuart-Siddall, Sandra; Haberlin, Jean

    This handbook provides Rural Clinical Nurse Placement Program (RCNP) preceptors with a program overview and practical suggestions to apply during student placement. An introductory section describes how the program addresses the maldistribution of nurses by raising awareness about the rural experience, adding a needed perspective to the urban bias…

  8. Understanding Successful Sandwich Placements: A Bourdieusian Approach

    ERIC Educational Resources Information Center

    Clark, Martyn; Zukas, Miriam

    2016-01-01

    Sandwich placements and other integrated work and study schemes are increasingly advocated as a key means by which universities can promote students' employability. However, there is little understanding of how successful placements work in terms of facilitating learning and development. Drawing on three longitudinal case studies of students who…

  9. Preparing ESP Learners for Workplace Placement

    ERIC Educational Resources Information Center

    Wood, David

    2009-01-01

    Engineering students in North American universities often participate in cooperative education placements in workplaces as part of the requirements for their degrees and professional certification. Students for whom English is an L2 often experience difficulties in these placements due to the fact that while their academic language ability may be…

  10. Implementation of Job Placement Services Guidelines.

    ERIC Educational Resources Information Center

    McGillicuddy (Shirley) & Associates, Sierra Madre, CA.

    The Implementation of Job Placement Services Guidelines Project was designed to strengthen placement programs and services for California community college vocational students, and for all students needing part-time employment to realize their educational goals. The project was designed to test the validity and relevance of quality indicators…

  11. Job Placement and the School Counselor.

    ERIC Educational Resources Information Center

    Goeke, John D.; Salomone, Paul R.

    1979-01-01

    The trend toward career education in the schools and its implications suggest the addition of job placement, especially client-centered placement, as part of the school counselor's responsibility. Planning for its eventual inclusion can only increase a counselor's ability to adapt in an ever-changing system of transient educational priorities.…

  12. A Risk-Based Sensor Placement Methodology

    SciTech Connect

    Lee, Ronald W; Kulesz, James J

    2006-08-01

    A sensor placement methodology is proposed to solve the problem of optimal location of sensors or detectors to protect population against the exposure to and effects of known and/or postulated chemical, biological, and/or radiological threats. Historical meteorological data are used to characterize weather conditions as wind speed and direction pairs with the percentage of occurrence of the pairs over the historical period. The meteorological data drive atmospheric transport and dispersion modeling of the threats, the results of which are used to calculate population at risk against standard exposure levels. Sensor locations are determined via a dynamic programming algorithm where threats captured or detected by sensors placed in prior stages are removed from consideration in subsequent stages. Moreover, the proposed methodology provides a quantification of the marginal utility of each additional sensor or detector. Thus, the criterion for halting the iterative process can be the number of detectors available, a threshold marginal utility value, or the cumulative detection of a minimum factor of the total risk value represented by all threats.

  13. Birth placement and child health.

    PubMed

    Fergusson, D M; Horwood, J; Shannon, F T

    1981-07-22

    The standards of health and health care for a sample of 1265 Christchurch children during the period birth to three years were examined. There was a systematic tendency for levels of health care and morbidity to vary with the child's birth placement: in general adopted children had the best standard of health care and the lowest rates of morbidity; children who entered single parent families at birth had the poorest standards of health care and the highest rates of morbidity. Statistical control for family social background including maternal age, education, ethnic status, family size and changes of residence tended to reduce the size of the observed differences. However, even when the results were controlled for these factors children in single parent families still has depressed levels of preventive health care and higher rates of hospital admission. Possible explanations of the differences are discussed. PMID:6944632

  14. An optimal design of X-ray target for uniform X-ray emission from an electronic brachytherapy system

    NASA Astrophysics Data System (ADS)

    Ihsan, Aamir; Heo, Sung Hwan; Kim, Hyun Jin; Kang, Chang Mu; Cho, Sung Oh

    2011-05-01

    We present a novel design of an X-ray target to deliver uniform dose from an electronic brachytherapy system (EBS). This design comprises of a combination of both the reflection- and transmission-type target geometries. Monte-Carlo simulation code MCNP5 has been employed for the calculation of angular distribution of the X-ray intensity produced from various morphologies of X-ray targets. The simulation results reveal that the combinatorial target-assembly is promising and effective in achieving uniformity of X-ray emission over the entire space of solid angle of 4 π in comparison to a transmission-type target that produces X-rays mainly in the forward direction and a reflection-type target that generates X-rays mostly in the backward direction. As a direct consequence of the uniformity of X-ray emission, the combinatorial target-assembly can impart a uniform dose distribution which makes it suitable as a target of an X-ray tube for EBS.

  15. Using more healthcare areas for placements.

    PubMed

    Sherratt, Lou; Whitehead, Bill; Young, Alwyn; Collins, Guy; Brundrett, Heather

    The need for private, voluntary and independent placements in nursing programmes has become more important in recent years due to changes in where health services are delivered. These placements can be used effectively within nursing programmes to show students the realities of healthcare, and to challenge myths and attitudes. Dedicated time and resources need to be provided to discover and maintain these placements, and to ensure appropriate, high-quality learning opportunities. This article presents the findings of a national Higher Education Academy workshop, held at the University of Derby in November 2012. It explores three key issues discussed at the workshop: current practice and opportunities for learning; myths, attitudes and solutions; and maintaining the quality of placements. The use of PVI placements is seen as valuable and a set of recommendations are provided to assist in their use. PMID:23905296

  16. SU-E-T-256: Optimizing the Combination of Targeted Radionuclide Therapy Agents Using a Multi-Scale Patient-Specific Monte Carlo Dosimetry Platform

    SciTech Connect

    Besemer, A; Bednarz, B; Titz, B; Grudzinski, J; Weichert, J; Hall, L

    2014-06-01

    Purpose: Combination targeted radionuclide therapy (TRT) is appealing because it can potentially exploit different mechanisms of action from multiple radionuclides as well as the variable dose rates due to the different radionuclide half-lives. The work describes the development of a multiobjective optimization algorithm to calculate the optimal ratio of radionuclide injection activities for delivery of combination TRT. Methods: The ‘diapeutic’ (diagnostic and therapeutic) agent, CLR1404, was used as a proof-of-principle compound in this work. Isosteric iodine substitution in CLR1404 creates a molecular imaging agent when labeled with I-124 or a targeted radiotherapeutic agent when labeled with I-125 or I-131. PET/CT images of high grade glioma patients were acquired at 4.5, 24, and 48 hours post injection of 124I-CLR1404. The therapeutic 131I-CLR1404 and 125ICLR1404 absorbed dose (AD) and biological effective dose (BED) were calculated for each patient using a patient-specific Monte Carlo dosimetry platform. The optimal ratio of injection activities for each radionuclide was calculated with a multi-objective optimization algorithm using the weighted sum method. Objective functions such as the tumor dose heterogeneity and the ratio of the normal tissue to tumor doses were minimized and the relative importance weights of each optimization function were varied. Results: For each optimization function, the program outputs a Pareto surface map representing all possible combinations of radionuclide injection activities so that values that minimize the objective function can be visualized. A Pareto surface map of the weighted sum given a set of user-specified importance weights is also displayed. Additionally, the ratio of optimal injection activities as a function of the all possible importance weights is generated so that the user can select the optimal ratio based on the desired weights. Conclusion: Multi-objective optimization of radionuclide injection activities

  17. A fast neural-network algorithm for VLSI cell placement.

    PubMed

    Aykanat, Cevdet; Bultan, Tevfik; Haritaoğlu, Ismail

    1998-12-01

    Cell placement is an important phase of current VLSI circuit design styles such as standard cell, gate array, and Field Programmable Gate Array (FPGA). Although nondeterministic algorithms such as Simulated Annealing (SA) were successful in solving this problem, they are known to be slow. In this paper, a neural network algorithm is proposed that produces solutions as good as SA in substantially less time. This algorithm is based on Mean Field Annealing (MFA) technique, which was successfully applied to various combinatorial optimization problems. A MFA formulation for the cell placement problem is derived which can easily be applied to all VLSI design styles. To demonstrate that the proposed algorithm is applicable in practice, a detailed formulation for the FPGA design style is derived, and the layouts of several benchmark circuits are generated. The performance of the proposed cell placement algorithm is evaluated in comparison with commercial automated circuit design software Xilinx Automatic Place and Route (APR) which uses SA technique. Performance evaluation is conducted using ACM/SIGDA Design Automation benchmark circuits. Experimental results indicate that the proposed MFA algorithm produces comparable results with APR. However, MFA is almost 20 times faster than APR on the average. PMID:12662737

  18. Target capture and target ghosts

    NASA Astrophysics Data System (ADS)

    Auerbach, Steven P.

    1996-05-01

    Optimal detection methods for small targets rely on whitened matched filters, which convolve the measured data with the signal model, and whiten the result with the noise covariance. In real-world implementations of such filters, the noise covariance must be estimated from the data, and the resulting covariance estimate may be corrupted by presence of the target. The resulting loss in SNR is called 'target capture'. Target capture is often thought to be a problem only for bright targets. This presentation shows that target capture also arises for dim targets, leading to an SNR loss which is independent of target strength and depends on the averaging method used to estimate the noise covariance. This loss is due to a 'coherent beat' between the true noise and that portion of the estimated noise covariance due to the target. This beat leads to 'ghost targets', which diminish the target SNR by producing a negative target ghost at the target's position. A quantitative estimate of this effect will be given, and shown to agree with numerical results. The effect of averaging on SNR is also discussed for data scenes with synthetic injected targets, in cases where the noise covariance is estimated using 'no target' data. For these cases, it is shown that the so-called 'optimal' filter, which uses the true noise covariance, is actually worse than a 'sub-optimal' filter which estimates the noise from scene. This apparent contradiction is resolved by showing that the optimal filter is best if the same filter is used for many scenes, but is outperformed by a filter adapted to a specific scene.

  19. Singular vector based targeted observations of chemical constituents: description and first application of the EURAD-IM-SVA

    NASA Astrophysics Data System (ADS)

    Goris, N.; Elbern, H.

    2015-08-01

    Measurements of the large dimensional chemical state of the atmosphere provide only sparse snapshots of the state of the system due to their typically insufficient temporal and spatial density. In order to optimize the measurement configurations despite those limitations, the present work describes the identification of sensitive states of the chemical system as optimal target areas for adaptive observations. For this purpose, the technique of singular vector analysis (SVA), which has been proved effective for targeted observations in numerical weather predication, is implemented into the chemical transport model EURAD-IM (EURopean Air pollution and Dispersion - Inverse Model) yielding the EURAD-IM-SVA. Besides initial values, emissions are investigated as critical simulation controlling targeting variables. For both variants, singular vectors are applied to determine the optimal placement for observations and moreover to quantify which chemical compounds have to be observed with preference. Based on measurements of the airship based ZEPTER-2 campaign, the EURAD-IM-SVA has been evaluated by conducting a comprehensive set of model runs involving different initial states and simulation lengths. Since the considered cases are restricted in terms of considered chemical compounds and selected areas, they allow for a retracing of the results and a confirmation of their correctness. Our analysis shows that the optimal placement for observations of chemical species is not entirely determined by mere transport and mixing processes. Rather, a combination of initial chemical concentrations, chemical conversions, and meteorological processes determine the influence of chemical compounds and regions. We furthermore demonstrate that the optimal placement of observations of emission strengths is highly dependent on the location of emission sources and that the benefit of including emissions as target variables outperforms the value of initial value optimisation with growing

  20. Setting standards for high-quality placements.

    PubMed

    Aitkenhead, Susan; Farran, Sean; Bateman, Ian

    As part of a project undertaken by a local education and training board, a wide range of stakeholders across South London were asked what makes a high-quality practice placement for student nurses, and how that quality could be effectively measured. This article outlines the drafting and testing of a set of quality standards in a mix of provider settings. Although further refinement is required, the standards enabled placement sites to question themselves about their own education and training processes, strengthened their partnership with the training and education board and facilitated the assurance that student nurses receive safe, effective and compassionate preparation when they are on placement. PMID:26434190

  1. Placement of tibial intraosseous infusion devices.

    PubMed

    Harcke, H Theodore; Crawley, Geoffrey; Mabry, Robert; Mazuchowski, Edward

    2011-07-01

    Post-mortem preautopsy multidetector computed tomography was used to assess the placement of tibial intraosseous infusion needles in 52 cases of battlefield trauma deaths for which medical intervention included the use of the technique. In 58 (95%) of 61 needles, the tip was positioned in medullary bone. All 3 (5%) unsuccessful placements were in the left leg, and the needle was not directed perpendicular to the medial tibial cortex as recommended. Considering the nature of military trauma and the environmental conditions under which care is rendered, military medical personnel appear to be highly successful in the placement of tibial intraosseous infusion needles. PMID:22128726

  2. Advanced fiber placement of composite fuselage structures

    NASA Technical Reports Server (NTRS)

    Anderson, Robert L.; Grant, Carroll G.

    1991-01-01

    The Hercules/NASA Advanced Composite Technology (ACT) program will demonstrate the low cost potential of the automated fiber placement process. The Hercules fiber placement machine was developed for cost effective production of composite aircraft structures. The process uses a low cost prepreg tow material form and achieves equivalent laminate properties to structures fabricated with prepreg tape layup. Fiber placement demonstrations planned for the Hercules/NASA program include fabrication of stiffened test panels which represent crown, keel, and window belt segments of a typical transport aircraft fuselage.

  3. Curcumin Loaded Microsponges for Colon Targeting in Inflammatory Bowel Disease: Fabrication, Optimization, and In Vitro and Pharmacodynamic Evaluation

    PubMed Central

    Nath, Kavita; Dhar, K. L.

    2014-01-01

    The present study was aimed to develop and optimize the microsponges of curcumin for colon specific drug delivery in a view to bypass the upper gastrointestinal tract (GIT) for enhanced therapeutic effect. Microsponges were developed by quasi emulsion solvent diffusion method using 32 full factorial design. Prepared microsponges were optimized in order to analyze the effects of independent variables (volume of ethanol and Eudragit L100) on the encapsulation efficiency, particle size, and drug release. The optimized formulation was subjected to in vivo study using acetic acid induced colitis model in rats. The F7 was selected as optimized formulation based on particle size of 41.63 μm, % entrapment efficiency of 78.13%, and % cumulative drug release of 84.12%, and desirability factor of 0.83. Release studies revealed that microsponges prevented the premature release of curcumin in upper GIT and specifically released the drug at colonic pH. The drug release profile of F7 formulation was subjected to different kinetic models and based upon the best correlation coefficient (r2 = 0.9927) the release was found to follow Higuchi model, which suggested diffusion as the main mechanism of drug release. Pharmacodynamic study showed that curcumin loaded microsponges causes a significant decrease in edema, necrosis, and hemorrhage of colon as compared to free curcumin. This study proves that curcumin loaded microsponges may act as a promising drug delivery system for treatment of ulcerative colitis. PMID:25093165

  4. Optimization of novel combi-molecules: identification of balanced and mixed bcr-abl/DNA targeting properties.

    PubMed

    Rachid, Zakaria; Katsoulas, Athanasia; Williams, Christopher; Larroque, Anne-Laure; McNamee, James; Jean-Claude, Bertrand J

    2007-08-01

    Steps toward the identification of combi-molecules with strong abl tyrosine kinase (TK) inhibitory property and significant DNA damaging potential are described. The optimized combi-molecule 13a was shown to induce approximately twofold stronger abl TK inhibitory activity than Gleevec and high levels of DNA damage in chronic myelogenous leukemic cells. PMID:17572088

  5. Novel small molecule inhibitors targeting the "switch region" of bacterial RNAP: structure-based optimization of a virtual screening hit.

    PubMed

    Sahner, J Henning; Groh, Matthias; Negri, Matthias; Haupenthal, Jörg; Hartmann, Rolf W

    2013-07-01

    Rising resistance against current antibiotics necessitates the development of antibacterial agents with alternative targets. The "switch region" of RNA polymerase (RNAP), addressed by the myxopyronins, could be such a novel target site. Based on a hit candidate discovered by virtual screening, a small library of 5-phenyl-3-ureidothiophene-2-carboxylic acids was synthesized resulting in compounds with increased RNAP inhibition. Hansch analysis revealed π (lipophilicity constant) and σ (Hammet substituent constant) of the substituents at the 5-phenyl moiety to be crucial for activity. The binding mode was proven by the targeted introduction of a moiety mimicking the enecarbamate side chain of myxopyronin into the hit compound, accompanied by enhanced RNAP inhibitory potency. The new compounds displayed good antibacterial activities against Gram positive bacteria and Gram negative Escherichia coli TolC and a reduced resistance frequency compared to the established antibiotic rifampicin. PMID:23711833

  6. Stress Placement in Tswana English: The Makings of a Coherent System.

    ERIC Educational Resources Information Center

    van Rooy, Bertus

    2002-01-01

    Investigates stress placement in one variety of Black South African English (BSAE), namely Tswana English. A corpus of 333 polysyllabic words was analyzed in detail to determine the properties of the Tswana English stress system; properties were interpreted by means of optimality theory. Concludes that stress is stored lexically in function words,…

  7. An MBO Approach to Placement Office Evaluation

    ERIC Educational Resources Information Center

    Storholm, Gordon R.

    1978-01-01

    This article investigates the basic functions and responsibilities of the college or university placement director and attempts to translate them into a specific MBO-oriented performance valuation format. (Author)

  8. Student life - Tips for placement success.

    PubMed

    2016-03-01

    Placements are an inevitable part of a nursing degree which provide a platform for on-the-job learning and development, greatly enhancing a student nurse's understanding of their career choice. PMID:26932655

  9. Educational Placement of Children with Spina Bifida.

    ERIC Educational Resources Information Center

    Lauder, Calvin E.; And Others

    1979-01-01

    Procedures of school placement for 38 children (ages 5 to 18 years) with spina bifida in 23 school districts in western New York State were studied 5 years after a mandated process was enacted. (Author)

  10. Nerves and excitement on my first placement.

    PubMed

    Cowen, Emma

    2016-09-12

    After working in the children's accident and emergency department as a healthcare assistant for three years before starting university, I am about to start a placement there as a nursing student. PMID:27615579

  11. Effect of codon optimization and subcellular targeting on Toxoplasma gondii antigen SAG1 expression in tobacco leaves to use in subcutaneous and oral immunization in mice

    PubMed Central

    2010-01-01

    Background Codon optimization and subcellular targeting were studied with the aim to increase the expression levels of the SAG178-322 antigen of Toxoplasma gondii in tobacco leaves. The expression of the tobacco-optimized and native versions of the SAG1 gene was explored by transient expression from the Agrobacterium tumefaciens binary expression vector, which allows targeting the recombinant protein to the endoplasmic reticulum (ER) and the apoplast. Finally, mice were subcutaneously and orally immunized with leaf extracts-SAG1 and the strategy of prime boost with rSAG1 expressed in Escherichia coli was used to optimize the oral immunization with leaf extracts-SAG1. Results Leaves agroinfiltrated with an unmodified SAG1 gene accumulated 5- to 10-fold more than leaves agroinfiltrated with a codon-optimized SAG1 gene. ER localization allowed the accumulation of higher levels of native SAG1. However, no significant differences were observed between the mRNA accumulations of the different versions of SAG1. Subcutaneous immunization with leaf extracts-SAG1 (SAG1) protected mice against an oral challenge with a non-lethal cyst dose, and this effect could be associated with the secretion of significant levels of IFN-γ. The protection was increased when mice were ID boosted with rSAG1 (SAG1+boost). This group elicited a significant Th1 humoral and cellular immune response characterized by high levels of IFN-γ. In an oral immunization assay, the SAG1+boost group showed a significantly lower brain cyst burden compared to the rest of the groups. Conclusion Transient agroinfiltration was useful for the expression of all of the recombinant proteins tested. Our results support the usefulness of endoplasmic reticulum signal peptides in enhancing the production of recombinant proteins meant for use as vaccines. The results showed that this plant-produced protein has potential for use as vaccine and provides a potential means for protecting humans and animals against

  12. Nursing students' perceptions of their clinical learning environment in placements outside traditional hospital settings

    PubMed Central

    Bjørk, Ida T; Berntsen, Karin; Brynildsen, Grethe; Hestetun, Margrete

    2014-01-01

    Aims and objectives To explore students' opinions of the learning environment during clinical placement in settings outside traditional hospital settings. Background Clinical placement experiences may influence positively on nursing students attitudes towards the clinical setting in question. Most studies exploring the quality of clinical placements have targeted students' experience in hospital settings. The number of studies exploring students' experiences of the learning environment in healthcare settings outside of the hospital venue does not match the growing importance of such settings in the delivery of health care, nor the growing number of nurses needed in these venues. Design A survey design was used. Method The Clinical Learning Environment Inventory was administered to two cohorts of undergraduate nursing students (n = 184) after clinical placement in mental health care, home care and nursing home care. Results Nursing students' overall contentment with the learning environment was quite similar across all three placement areas. Students in mental health care had significantly higher scores on the subscale individualisation, and older students had significantly higher scores on the total scale. Compared with other studies where the Clinical Learning Environment Inventory has been used, the students' total scores in this study are similar or higher than scores in studies including students from hospital settings. Conclusion Results from this study negate the negative views on clinical placements outside the hospital setting, especially those related to placements in nursing homes and mental healthcare settings. Relevance to clinical practice Students' experience of the learning environment during placements in mental health care, home care and nursing homes indicates the relevance of clinical education in settings outside the hospital setting. PMID:24460862

  13. Contact-facilitated drug delivery with Sn2 lipase labile prodrugs optimize targeted lipid nanoparticle drug delivery.

    PubMed

    Pan, Dipanjan; Pham, Christine T N; Weilbaecher, Katherine N; Tomasson, Michael H; Wickline, Samuel A; Lanza, Gregory M

    2016-01-01

    Sn2 lipase labile phospholipid prodrugs in conjunction with contact-facilitated drug delivery offer an important advancement in Nanomedicine. Many drugs incorporated into nanosystems, targeted or not, are substantially lost during circulation to the target. However, favorably altering the pharmacokinetics and volume of distribution of systemic drug delivery can offer greater efficacy with lower toxicity, leading to new prolonged-release nanoexcipients. However, the concept of achieving Paul Erhlich's inspired vision of a 'magic bullet' to treat disease has been largely unrealized due to unstable nanomedicines, nanosystems achieving low drug delivery to target cells, poor intracellular bioavailability of endocytosed nanoparticle payloads, and the substantial biological barriers of extravascular particle penetration into pathological sites. As shown here, Sn2 phospholipid prodrugs in conjunction with contact-facilitated drug delivery prevent premature drug diffusional loss during circulation and increase target cell bioavailability. The Sn2 phospholipid prodrug approach applies equally well for vascular constrained lipid-encapsulated particles and micelles the size of proteins that penetrate through naturally fenestrated endothelium in the bone marrow or thin-walled venules of an inflamed microcirculation. At one time Nanomedicine was considered a 'Grail Quest' by its loyal opposition and even many in the field adsorbing the pains of a long-learning curve about human biology and particles. However, Nanomedicine with innovations like Sn2 phospholipid prodrugs has finally made 'made the turn' toward meaningful translational success. PMID:26296541

  14. Optimizing tumor targeting of the lipophilic EGFR-binding radiotracer SKI 243 using a liposomal nanoparticle delivery system.

    PubMed

    Medina, Oula Penate; Pillarsetty, Nagavarakishore; Glekas, Athanasios; Punzalan, Blesida; Longo, Valerie; Gönen, Mithat; Zanzonico, Pat; Smith-Jones, Peter; Larson, Steven M

    2011-02-10

    Positron emission tomography (PET) of epidermal growth factor receptor (EGFR) kinase-specific radiolabeled tracers could provide a means for non-invasively characterizing EGFR expression and signaling activity in patients' tumors before, during, and after therapy with EGFR inhibitors. Towards this goal, our group has developed PET tracers which irreversibly bind to EGFR. However, tumor uptake is relatively low because of both the lipophilicity of such tracers (e.g. the morpholino-[124I]-IPQA [SKI 212243]), with octanol-to-water partition coefficients of up to 4, and a short dwell time in the blood and significant hepatobiliary clearance and intestinal reuptake. Liposomal nanoparticle delivery systems may favorably alter the pharmacokinetic profile and improve tumor targeting of highly lipophilic but otherwise promising cancer imaging tracers, such as the EGFR inhibitor SKI 243. SKI 243 is therefore an interesting model molecule for incorporation into lipid-based nanoparticles, as it would not only improve their solubility but also increase the circulation time, availability and, potentially, targeting of tumors. In the current study, we compared the pharmacokinetics and tumor targeting of the bare EGFR kinase-targeting radiotracer SKI 212243 (SKI 243) with that of the same tracer embedded in liposomes. SKI 243 and liposomal SKI 243 are both taken up by tumor xenografts but liposomal SKI 243 remained in the blood longer and consequently exhibited a 3- to 6-fold increase in uptake in the tumor among several other organs. PMID:21047536

  15. Optimizing tumor targeting of the lipophilic EGFR-binding radiotracer SKI243 using a liposomal nanoparticle delivery system

    PubMed Central

    Pillarsetty, Nagavarakishore; Glekas, Athanasios; Punzalan, Blesida; Longo, Valerie; Gönen, Mithat; Zanzonico, Pat; Smith-Jones, Peter

    2015-01-01

    Positron emission tomography (PET) of epidermal growth factor receptor (EGFR) kinase-specific radiolabeled tracers could provide a means for non-invasively characterizing EGFR expression and signaling activity in patients' tumors before, during, and after therapy with EGFR inhibitors. Towards this goal, our group has developed PET tracers which irreversibly bind to EGFR. However, tumor uptake is relatively low because of both the lipophilicity of such tracers (e.g. the morpholino-[124I]-IPQA [SKI212243]), with octanol-to-water partition coefficients of up to 4, and a short dwell time in the blood and significant hepatobiliary clearance and intestinal reuptake. Liposomal nanoparticle delivery systems may favorably alter the pharmacokinetic profile and improve tumor targeting of highly lipophilic but otherwise promising cancer imaging tracers, such as the EGFR inhibitor SKI243. SKI243 is therefore an interesting model molecule for incorporation into lipid-based nanoparticles, as it would not only improve their solubility but also increase the circulation time, availability and, potentially, targeting of tumors. In the current study, we compared the pharmacokinetics and tumor targeting of the bare EGFR kinase-targeting radiotracer SKI212243 (SKI243) with that of the same tracer embedded in liposomes. SKI243 and liposomal SKI243 are both taken up by tumor xenografts but liposomal SKI243 remained in the blood longer and consequently exhibited a 3- to 6-fold increase in uptake in the tumor among several other organs. PMID:21047536

  16. Optimization of some laser and target features for laser-plasma interaction in the context of fusion

    NASA Astrophysics Data System (ADS)

    Depierreux, S.; Labaune, C.; Michel, D. T.; Tikhonchuk, V. T.; Tassin, V.; Stenz, C.; Borisenko, N. G.; Nazarov, W.; Grech, M.; Hüller, S.; Limpouch, J.; Loiseau, P.; Nicolaï, P.; Pesme, D.; Rozmus, W.; Meyer, C.; D-Nicola, P.; Wrobel, R.; Alozy, E.; Romary, P.; Thiell, G.; Soullié, G.; Reverdin, C.; Villette, B.; Rabec-le-Gloahec, M.; Godinho, C.

    2008-05-01

    This paper presents experimental results obtained at LULI 2000 and LIL about (i) the compared laser plasma coupling at 526 (2ω) and 351 nm (3ω) and (ii) the early laser imprint suppression using foam targets as plasma smoother of the laser beam. Both experiments are described, part of the experimental results are presented and discussed.

  17. Optimizing EMI transmitter and receiver configurations to enhance detection and identification of small and deep metallic targets

    NASA Astrophysics Data System (ADS)

    Fernández, Juan Pablo; Barrowes, Benjamin; Bijamov, Alex; O'Neill, Kevin; Shamatava, Irma; Steinhurst, Daniel A.; Shubitidze, Fridon

    2012-06-01

    Current electromagnetic induction (EMI) sensors of the kind used to discriminate buried unexploded orndance (UXO) can detect targets down to a depth limited by the geometric size of the transmitter (Tx) coils, the amplitudes of the transmitting currents, and the noise floor of the receivers (Rx). The last two factors are not independent: for example, one cannot detect a deeply buried target simply by increasing the amplitude of the Tx current, since this also increases the noise and thus does not improve the SNR. The problem could in principle be overcome by increasing the size of the Tx coils and thus their moment. Current multi-transmitter instruments such as the TEMTADS sensor array can be electronically tweaked to provide a big Tx moment: they can be modified to transmit signals from two, three or more Tx coils simultaneously. We investigate the possibility of enhancing the deep-target detection capability of TEMTADS by exploring different combinations of Tx coils. We model different multi-Tx combinations within TEMTADS using a full-3D EMI solver based on the method of auxiliary sources (MAS).We determine the feasibility of honing these combinations for enhanced detection and discrimination of deep targets. We investigate how to improve the spatial resolution and focusing properties of the primary magnetic field by electronically adjusting the currents of the transmitters. We apply our findings to data taken at different UXO live sites.

  18. Contact-facilitated drug delivery with Sn2 lipase labile prodrugs optimize targeted lipid nanoparticle drug delivery

    PubMed Central

    Pan, Dipanjan; Pham, Christine TN; Weilbaecher, Katherine N; Tomasson, Michael H; Wickline, Samuel A; Lanza, Gregory M

    2016-01-01

    Sn2 lipase labile phospholipid prodrugs in conjunction with contact-facilitated drug delivery offer an important advancement in Nanomedicine. Many drugs incorporated into nanosystems, targeted or not, are substantially lost during circulation to the target. However, favorably altering the pharmacokinetics and volume of distribution of systemic drug delivery can offer greater efficacy with lower toxicity, leading to new prolonged-release nanoexcipients. However, the concept of achieving Paul Erhlich's inspired vision of a ‘magic bullet’ to treat disease has been largely unrealized due to unstable nanomedicines, nanosystems achieving low drug delivery to target cells, poor intracellular bioavailability of endocytosed nanoparticle payloads, and the substantial biological barriers of extravascular particle penetration into pathological sites. As shown here, Sn2 phospholipid prodrugs in conjunction with contact-facilitated drug delivery prevent premature drug diffusional loss during circulation and increase target cell bioavailability. The Sn2 phospholipid prodrug approach applies equally well for vascular constrained lipid-encapsulated particles and micelles the size of proteins that penetrate through naturally fenestrated endothelium in the bone marrow or thin-walled venules of an inflamed microcirculation. At one time Nanomedicine was considered a ‘Grail Quest’ by its loyal opposition and even many in the field adsorbing the pains of a long-learning curve about human biology and particles. However, Nanomedicine with innovations like Sn2 phospholipid prodrugs has finally made ‘made the turn’ toward meaningful translational success. PMID:26296541

  19. Placement of Neochords in Mitral Valve Repair: Enhanced Exposure of the Papillary Muscles Using a Standard Valve Sizer.

    PubMed

    Erlebach, Magdalena; Lange, Ruediger; Mazzitelli, Domenico

    2016-01-01

    Minimally invasive mitral valve repair with placement of artificial chordae for mitral valve regurgitation has become the standard of care. In some cases, such as Barlow's disease or bileaflet prolapse, papillary muscle exposure may be difficult. By using a valve sizer to retract both leaflets, visualization can be optimized, thus simplifying suture placement and thereby minimizing cross-clamp and cardiopulmonary bypass times. This technique is simple, is cost effective, and can be applied quickly. PMID:26694289

  20. Spatial optimization of watershed management practices for nitrogen load reduction using a modeling-optimization framework.

    PubMed

    Yang, Guoxiang; Best, Elly P H

    2015-09-15

    Best management practices (BMPs) can be used effectively to reduce nutrient loads transported from non-point sources to receiving water bodies. However, methodologies of BMP selection and placement in a cost-effective way are needed to assist watershed management planners and stakeholders. We developed a novel modeling-optimization framework that can be used to find cost-effective solutions of BMP placement to attain nutrient load reduction targets. This was accomplished by integrating a GIS-based BMP siting method, a WQM-TMDL-N modeling approach to estimate total nitrogen (TN) loading, and a multi-objective optimization algorithm. Wetland restoration and buffer strip implementation were the two BMP categories used to explore the performance of this framework, both differing greatly in complexity of spatial analysis for site identification. Minimizing TN load and BMP cost were the two objective functions for the optimization process. The performance of this framework was demonstrated in the Tippecanoe River watershed, Indiana, USA. Optimized scenario-based load reduction indicated that the wetland subset selected by the minimum scenario had the greatest N removal efficiency. Buffer strips were more effective for load removal than wetlands. The optimized solutions provided a range of trade-offs between the two objective functions for both BMPs. This framework can be expanded conveniently to a regional scale because the NHDPlus catchment serves as its spatial computational unit. The present study demonstrated the potential of this framework to find cost-effective solutions to meet a water quality target, such as a 20% TN load reduction, under different conditions. PMID:26188990