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Sample records for optimal loading dose

  1. Loading dose of Dexdor(®) and optimal sedation during oral and maxillofacial ambulatory surgery procedures: An observational study.

    Science.gov (United States)

    Martinez-Simon, A; Cacho-Asenjo, E; Hernando, B; Honorato-Cia, C; Naval, L; Panadero, A; Nuñez-Cordoba, J M

    2017-04-01

    Dexdor(®) do not include the possibility of loading dose, which could increase time to achieve adequate sedation for ambulatory procedures. The objective of this study was to evaluate the effect of several loading dose of dexmedetomidine in the time to achieve and maintain an optimal level of sedation and its clinical hemodynamic repercussion. The IRB approved this observational study for patients that underwent oral and maxillofacial ambulatory surgery under dexmedetomidine at the University of Navarra Clinic from February 2013 to November 2014. According to the loading dose the patients were grouped into 3 categories:0.5μg/kg. Optimal level of sedation was defined as bispectral index0.5μg/kg loading dose categories for achieving a bispectral index0.5μg/kg showed greater risk of requiring atropine compared with the group0.5μg/kg appears minimize the time to achieve and maintain an optimal level of sedation during the first 60min of procedure. Further investigation to elucidate the association between loading dose of dexmedetomidine and subsequent atropine requirements may be warranted. Copyright © 2016 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

  2. Optimal Load Dispatch Using Ant Lion Optimization

    Directory of Open Access Journals (Sweden)

    Menakshi Mahendru Nischal

    2015-08-01

    Full Text Available This paper presents Ant lion optimization (ALO technique to solve optimal load dispatch problem. Ant lion optimization (ALO is a novel nature inspired algorithm. The ALO algorithm mimics the hunting mechanism of ant lions in nature. Five main steps of hunting prey such as the random walk of ants, building traps, entrapment of ants in traps, catching preys, and re-building traps are implemented. Optimal load dispatch (OLD is a method of determining the most efficient, low-cost and reliable operation of a power system by dispatching available electricity generation resources to supply load on the system. The primary objective of OLD is to minimize total cost of generation while honoring operational constraints of available generation resources. The proposed technique is implemented on 3, 6 & 20 unit test system for solving the OLD. Numerical results shows that the proposed method has good convergence property and better in quality of solution than other algorithms reported in recent literature.

  3. Optimal load shedding and restoration

    Science.gov (United States)

    Xu, Ding

    Load shedding is an emergency control action in power systems that can save systems from a wide-area blackout. Underfrequency load shedding, steady state load shedding, and voltage load shedding are widely used in power systems. These methods utilize either the steady state model or a simplified dynamic model to represent a power systems. In this dissertation, a general optimal load shedding method that considers both the dynamic process and load distribution is proposed. The unfavorable load shedding is then formulated as an optimization problem with the objective function of cost minimization. This objective function is subjected to system, security, and operation constraints. The entire problem becomes a question of optimization with differential and nonlinear equations as constraints. To solve this problem, discretization is used to change the differential equations into algebraic equations. The original problem is thus reformulated as an optimization problem and can be solved by a standard mathematical program. The general idea is then applied to traditional power systems, deregulated power systems, power systems with distributed generation, and load restoration. In the traditional power system, the method shows that governor action, generation dynamic, disturbance location, and economic factors can be taken into consideration. In the deregulated power system, two power market models are developed and incorporated into the load shedding scheme. In power systems with multiple distributed generations, the different cases of disturbances are analyzed and models of different distributed generation developed. The general idea is then applied. Finally, the load restoration problem is studied, and it is proposed that an optimization method be applied to it. This dissertation provides a comprehensive solution for load shedding problem in power systems. The models developed in this research can also be used to study other power system problems.

  4. Multiple anatomy optimization of accumulated dose

    Energy Technology Data Exchange (ETDEWEB)

    Watkins, W. Tyler, E-mail: watkinswt@virginia.edu; Siebers, Jeffrey V. [Department of Radiation Oncology, University of Virginia, Charlottesville, Virginia 22908 and Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298 (United States); Moore, Joseph A. [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, Maryland 21231 and Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298 (United States); Gordon, James [Henry Ford Health System, Detroit, Michigan 48202 and Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298 (United States); Hugo, Geoffrey D. [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298 (United States)

    2014-11-01

    Purpose: To investigate the potential advantages of multiple anatomy optimization (MAO) for lung cancer radiation therapy compared to the internal target volume (ITV) approach. Methods: MAO aims to optimize a single fluence to be delivered under free-breathing conditions such that the accumulated dose meets the plan objectives, where accumulated dose is defined as the sum of deformably mapped doses computed on each phase of a single four dimensional computed tomography (4DCT) dataset. Phantom and patient simulation studies were carried out to investigate potential advantages of MAO compared to ITV planning. Through simulated delivery of the ITV- and MAO-plans, target dose variations were also investigated. Results: By optimizing the accumulated dose, MAO shows the potential to ensure dose to the moving target meets plan objectives while simultaneously reducing dose to organs at risk (OARs) compared with ITV planning. While consistently superior to the ITV approach, MAO resulted in equivalent OAR dosimetry at planning objective dose levels to within 2% volume in 14/30 plans and to within 3% volume in 19/30 plans for each lung V20, esophagus V25, and heart V30. Despite large variations in per-fraction respiratory phase weights in simulated deliveries at high dose rates (e.g., treating 4/10 phases during single fraction beams) the cumulative clinical target volume (CTV) dose after 30 fractions and per-fraction dose were constant independent of planning technique. In one case considered, however, per-phase CTV dose varied from 74% to 117% of prescription implying the level of ITV-dose heterogeneity may not be appropriate with conventional, free-breathing delivery. Conclusions: MAO incorporates 4DCT information in an optimized dose distribution and can achieve a superior plan in terms of accumulated dose to the moving target and OAR sparing compared to ITV-plans. An appropriate level of dose heterogeneity in MAO plans must be further investigated.

  5. Loaded Gelled Bipropellants for Optimized Performance Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The focus of this program is the development and validation of formulations, and development methodologies, for optimizing high-performance particulate-loaded...

  6. Economic Load Dispatch Using Grey Wolf Optimization

    Directory of Open Access Journals (Sweden)

    Dr.Sudhir Sharma

    2015-04-01

    Full Text Available This paper presents grey wolf optimization (GWO to solve convex economic load dispatch (ELD problem. Grey Wolf Optimization (GWO is a new meta-heuristic inspired by grey wolves. The leadership hierarchy and hunting mechanism of the grey wolves is mimicked in GWO. The objective of ELD problem is to minimize the total generation cost while fulfilling the different constraints, when the required load of power system is being supplied. The proposed technique is implemented on two different test systems for solving the ELD with various load demands. To show the effectiveness of GWO to solve ELD problem results were compared with other existing techniques.

  7. Topology optimization of inertia driven dosing units

    DEFF Research Database (Denmark)

    Andreasen, Casper Schousboe

    2016-01-01

    This paper presents a methodology for optimizing inertia driven dosing units, sometimes referred to as eductors, for use in small scale flow applications. The unit is assumed to operate at low to moderate Reynolds numbers and under steady state conditions. By applying topology optimization...

  8. Optimizing lithium dosing in hemodialysis

    DEFF Research Database (Denmark)

    Bjarnason, N H; Munkner, R; Kampmann, J P

    2006-01-01

    We studied a 62-year-old female hemodialysis patient during initiation and maintenance of lithium carbonate therapy. Three different methods were applied to estimate the regimen: a scenario based on volume of distribution (V(d)), a scenario based on glomerular filtration rate (GFR), and a scenario...... estimates. Furthermore, the maintenance dose estimated from the central compartment (V1) led to plasma concentrations within the therapeutic range. Thus, a regimen where 12.2 mmol lithium was given after each hemodialysis session resulted in stable between-dialysis plasma lithium concentrations...... in this patient with no residual kidney function. We did not observe adverse effects related to this regimen, which was monitored from 18 days to 8 months of therapy, and the patient experienced relief from her severe depressive disorder. In conclusion, dialysis patients may be treated with lithium administrated...

  9. Optimal radiotherapy dose schedules under parametric uncertainty

    Science.gov (United States)

    Badri, Hamidreza; Watanabe, Yoichi; Leder, Kevin

    2016-01-01

    We consider the effects of parameter uncertainty on the optimal radiation schedule in the context of the linear-quadratic model. Our interest arises from the observation that if inter-patient variability in normal and tumor tissue radiosensitivity or sparing factor of the organs-at-risk (OAR) are not accounted for during radiation scheduling, the performance of the therapy may be strongly degraded or the OAR may receive a substantially larger dose than the allowable threshold. This paper proposes a stochastic radiation scheduling concept to incorporate inter-patient variability into the scheduling optimization problem. Our method is based on a probabilistic approach, where the model parameters are given by a set of random variables. Our probabilistic formulation ensures that our constraints are satisfied with a given probability, and that our objective function achieves a desired level with a stated probability. We used a variable transformation to reduce the resulting optimization problem to two dimensions. We showed that the optimal solution lies on the boundary of the feasible region and we implemented a branch and bound algorithm to find the global optimal solution. We demonstrated how the configuration of optimal schedules in the presence of uncertainty compares to optimal schedules in the absence of uncertainty (conventional schedule). We observed that in order to protect against the possibility of the model parameters falling into a region where the conventional schedule is no longer feasible, it is required to avoid extremal solutions, i.e. a single large dose or very large total dose delivered over a long period. Finally, we performed numerical experiments in the setting of head and neck tumors including several normal tissues to reveal the effect of parameter uncertainty on optimal schedules and to evaluate the sensitivity of the solutions to the choice of key model parameters.

  10. Dose-shaping using targeted sparse optimization

    Energy Technology Data Exchange (ETDEWEB)

    Sayre, George A.; Ruan, Dan [Department of Radiation Oncology, University of California - Los Angeles School of Medicine, 200 Medical Plaza, Los Angeles, California 90095 (United States)

    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

  11. Antenatal steroids: can we optimize the dose?

    Science.gov (United States)

    Romejko-Wolniewicz, Ewa; Teliga-Czajkowska, Justyna; Czajkowski, Krzysztof

    2014-01-01

    Purpose of review The beneficial effects of antenatal steroids in women at risk of preterm birth are evident. A dose of 24 mg appears sufficient, but there are insufficient data to recommend betamethasone or dexamethasone, a single steroid dose, the optimal interval between doses and repeated courses, the gestational age at which treatment is beneficial and the long-term effects of steroid treatment. This review addresses these aspects of antenatal steroid treatment. Recent findings Although the 12-h and 24-h dosing intervals are equivalent with respect to prevention of respiratory distress syndrome, the former enables the completion of treatment in 50% more neonates delivered prematurely. Reducing the single steroid dose in patients at risk for premature birth reduces the associated maternal side effects. An inverse relationship has been demonstrated between the number of corticosteroid courses and foetal growth. The reduced size of exposed foetuses has been attributed to birth at earlier gestational ages and decreased foetal growth. Evidence suggests that antenatal exposure to synthetic glucocorticoids in term-born children has long-lasting effects, which may have important implications in the recommendation of steroids before elective caesarean at term. Summary The short-term and long-term effects of the dosage regimen on the pregnant mother and foetus remain unclear. PMID:24463225

  12. Fast dose optimization for rotating shield brachytherapy.

    Science.gov (United States)

    Cho, Myung; Wu, Xiaodong; Dadkhah, Hossein; Yi, Jirong; Flynn, Ryan T; Kim, Yusung; Xu, Weiyu

    2017-07-26

    To provide a fast computational method, based on the proximal graph solver (POGS) - a convex optimization solver using the alternating direction method of multipliers (ADMM), for calculating an optimal treatment plan in rotating shield brachytherapy (RSBT). RSBT treatment planning has more degrees of freedom than conventional high-dose-rate brachytherapy due to the addition of emission direction, and this necessitates a fast optimization technique to enable clinical usage. The multi-helix RSBT (H-RSBT) delivery technique(1) was investigated for five representative cervical cancer patients. Treatment plans were generated for all patients using the POGS method and the commercially available solver IBM ILOG CPLEX(2) . The rectum, bladder, sigmoid colon, high-risk clinical target volume (HRCTV), and HR-CTV boundary were the structures included in our optimization, which applied an asymmetric dose-volume optimization with smoothness control. Dose calculation resolution was 1X1X3 mm(3) for all cases. The H-RSBT applicator had 6 helices, with 33:3 mm of translation along the applicator per helical rotation and 1:7 mm spacing between dwell positions, yielding 17.5° emission angle spacing per 5 mm along the applicator. For each patient, HR-CTV D90, HR-CTV D100, rectum D2cc, sigmoid D2cc, and bladder D2cc matched within 1% for CPLEX and POGS methods. Also, similar EQD2 values between CPLEX and POGS methods were obtained. POGS was around 18 times faster than CPLEX. Over all patients, total optimization times were 32.1-65.4 seconds for CPLEX and 2.1-3.9 seconds for POGS. POGS reduced treatment plan optimization time approximately 18 times for RSBT with similar HR-CTV D90, organ at risk (OAR) D2cc values, and EQD2 values compared to CPLEX, which is significant progress toward clinical translation of RSBT. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  13. Antibiotic dose optimization in critically ill patients.

    Science.gov (United States)

    Cotta, M O; Roberts, J A; Lipman, J

    2015-12-01

    The judicious use of existing antibiotics is essential for preserving their activity against infections. In the era of multi-drug resistance, this is of particular importance in clinical areas characterized by high antibiotic use, such as the ICU. Antibiotic dose optimization in critically ill patients requires sound knowledge not only of the altered physiology in serious infections - including severe sepsis, septic shock and ventilator-associated pneumonia - but also of the pathogen-drug exposure relationship (i.e. pharmacokinetic/pharmacodynamic index). An important consideration is the fact that extreme shifts in organ function, such as those seen in hyperdynamic patients or those with multiple organ dysfunction syndrome, can have an impact upon drug exposure, and constant vigilance is required when reviewing antibiotic dosing regimens in the critically ill. The use of continuous renal replacement therapy and extracorporeal membrane oxygenation remain important interventions in these patients; however, both of these treatments can have a profound effect on antibiotic exposure. We suggest placing emphasis on the use of therapeutic drug monitoring and dose individualization when optimizing therapy in these settings. Copyright © 2015 Elsevier España, S.L.U. and SEMICYUC. All rights reserved.

  14. Radiation protection: doses estimation and optimization; Radioprotection: estimation des doses et optimisation

    Energy Technology Data Exchange (ETDEWEB)

    Scanff, P.; Aubert, B.; Lebreton, C.; Rehel, J.L.; Brisse, H.; Madec, L.; Gaboriaud, G.; Lemoine, T.; Neuenschwander, S.; Rosenwald, J.C.; Tack, D.; Gevenois, P.A.; Robilliard, M.; Bayol, A

    2006-10-15

    The objectives were to bring notions relative to the safety of the procedures, notably in term of irradiation and the good use of the examinations in hospitals: biology, imaging, functional tests, endoscopy. The various approached subjects are: knowledge of the medical exposures to the ionising radiations, indicators for the dose to patient; The point on the collection of the data necessary for the update of the diagnostic reference levels, 2 years after the appearance of the order of February 12., 2004; Determination of the exposure of the premature babies in intensive care of neonates in the Beclere hospital; Calculation of the effective dose for T.D.M. acquisitions: comparison of dedicated software available on the market; Analysis of the system of automatic modulation of the load in T.D.M. on pediatric phantoms; dosimetry study of scanner examinations with automatic modulation of the load on pediatric phantoms; optimization image quality/dose in pediatric computed tomography with contrast product: use of a factor of merit. (N.C.)

  15. Optimal dose of dexmedetomidine for sedation during spinal anesthesia

    Science.gov (United States)

    Ok, Hwoe-Gyeong; Baik, Seong-Wan; Kim, Hae-Kyu; Shin, Sang-Wook; Kim, Kyung-Hoon

    2013-01-01

    Background Sedation in spinal anesthesia can reduce patient's anxiety and discomfort. Dexmedetomidine has a sedative, hypnotic, analgesic, and minimal respiratory depression effect. However, use of the dexmedetomidine is associated with prolonged recovery. This study was designed to investigate the optimal dose of intravenous dexmedetomidine for proper sedation with minimal recovery time in spinal anesthesia. Methods One hundred twenty eight patients, aged 20-70 years (58.8 ± 0.7), were recruited. After performing the spinal anesthesia with hyperbaric bupivacaine (13 mg), a loading dose of dexmedetomidine (1 µg/kg) was administered for 10 min, followed by the maintenance infusion of the following: Group A (n = 33; normal saline), Group B (n = 35; dexmedetomidine 0.2 µg/kg/hr), and Group C (n = 39; dexmedetomidine 0.4 µg/kg/hr). Heart rate, blood pressure, and the bispectral index score (BIS) were recorded during the operation. In the recovery room, modified aldrete score (MAS) was measured. Results There were no significant differences in mean blood pressure and heart rate among the three groups. BIS was not significantly different among the three groups from baseline to 60 min after the infusion of dexmedetomidine. BIS were significantly increased in Group A after 70 and 80 min, and Group A and B after 90, 100, 110 min of dexmedetomidine infusion (P < 0.05). MAS was higher in Group A as compared to Group B and C, within 30 min after admission in the recovery room (P < 0.05). Conclusions The loading dose (1 µg/kg/10 min) of dexmedetomidine was sufficient for surgery of less than 60 min. Dexmedetomidine infusion followed by maintenance dose (0.2 µg/kg/hr) was sufficient for surgery within 90 min. PMID:23741565

  16. Optimal load scheduling in commercial and residential microgrids

    Science.gov (United States)

    Ganji Tanha, Mohammad Mahdi

    Residential and commercial electricity customers use more than two third of the total energy consumed in the United States, representing a significant resource of demand response. Price-based demand response, which is in response to changes in electricity prices, represents the adjustments in load through optimal load scheduling (OLS). In this study, an efficient model for OLS is developed for residential and commercial microgrids which include aggregated loads in single-units and communal loads. Single unit loads which include fixed, adjustable and shiftable loads are controllable by the unit occupants. Communal loads which include pool pumps, elevators and central heating/cooling systems are shared among the units. In order to optimally schedule residential and commercial loads, a community-based optimal load scheduling (CBOLS) is proposed in this thesis. The CBOLS schedule considers hourly market prices, occupants' comfort level, and microgrid operation constraints. The CBOLS' objective in residential and commercial microgrids is the constrained minimization of the total cost of supplying the aggregator load, defined as the microgrid load minus the microgrid generation. This problem is represented by a large-scale mixed-integer optimization for supplying single-unit and communal loads. The Lagrangian relaxation methodology is used to relax the linking communal load constraint and decompose the independent single-unit functions into subproblems which can be solved in parallel. The optimal solution is acceptable if the aggregator load limit and the duality gap are within the bounds. If any of the proposed criteria is not satisfied, the Lagrangian multiplier will be updated and a new optimal load schedule will be regenerated until both constraints are satisfied. The proposed method is applied to several case studies and the results are presented for the Galvin Center load on the 16th floor of the IIT Tower in Chicago.

  17. Safety and tolerability of an oral zonisamide loading dose.

    Science.gov (United States)

    Jongeling, Amy C; Richins, Rachel J; Bazil, Carl W

    2015-11-01

    There are a limited number of anticonvulsant medications that can be administered with an oral loading dose in order to rapidly achieve an effective serum level, and most of these have associated adverse effects. Zonisamide is approved for the treatment of partial onset epilepsy, and is used in practice for both generalized and partial onset epilepsy. It is generally well-tolerated, has a long half-life, and can be administered once daily. Unfortunately, the recommended titration schedule for initiating therapy takes several weeks to reach target dose and therapeutic serum levels. We initiated zonisamide therapy using a large initial dose of zonisamide in 32 patients in our epilepsy monitoring unit over the past four years. Adverse effects were rare and involved nausea/vomiting (9.4%) or drowsiness (6.3%). In patients where serum levels were available for review, therapeutic or near-therapeutic levels were achieved after an oral load of 600-900 mg given as divided doses over a 6-12h period. This report is the first to suggest a method of rapidly initiating zonisamide therapy, achieving therapeutic serum levels in a shorter time frame, with an adverse effect profile similar to the recommended titration schedule. Copyright © 2015 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

  18. GENETIC ALGORITHM BASED CONCEPT DESIGN TO OPTIMIZE NETWORK LOAD BALANCE

    Directory of Open Access Journals (Sweden)

    Ashish Jain

    2012-07-01

    Full Text Available Multiconstraints optimal network load balancing is an NP-hard problem and it is an important part of traffic engineering. In this research we balance the network load using classical method (brute force approach and dynamic programming is used but result shows the limitation of this method but at a certain level we recognized that the optimization of balanced network load with increased number of nodes and demands is intractable using the classical method because the solution set increases exponentially. In such case the optimization techniques like evolutionary techniques can employ for optimizing network load balance. In this paper we analyzed proposed classical algorithm and evolutionary based genetic approach is devise as well as proposed in this paper for optimizing the balance network load.

  19. Power System Aggregate Load Area Modelling by Particle Swarm Optimization

    Institute of Scientific and Technical Information of China (English)

    Jian-Lin Wei; Ji-Hong Wang; Q.H.Wu; Nan Lu

    2005-01-01

    This paper presents a new approach for deriving a power system aggregate load area model (ALAM). In this approach, an equivalent area load model is derived to represent the load characters for a particular area load of a power system network. The Particle Swarm Optimization (PSO) method is employed to identify the unknown parameters of the generalised system, ALAM, based on the system measurement directly using a one-step scheme. Simulation studies are carried out for an IEEE 14-Bus power system and an IEEE 57-Bus power system. Simulation results show that the ALAM can represent the area load characters accurately under different operational conditions and at different power system states.

  20. Dose optimization of intra-operative high dose rate interstitial brachytherapy implants for soft tissue sarcoma

    Directory of Open Access Journals (Sweden)

    Jamema Swamidas

    2009-01-01

    Full Text Available Objective : A three dimensional (3D image-based dosimetric study to quantitatively compare geometric vs. dose-point optimization in combination with graphical optimization for interstitial brachytherapy of soft tissue sarcoma (STS. Materials and Methods : Fifteen consecutive STS patients, treated with intra-operative, interstitial Brachytherapy, were enrolled in this dosimetric study. Treatment plans were generated using dose points situated at the "central plane between the catheters", "between the catheters throughout the implanted volume", at "distances perpendicular to the implant axis" and "on the surface of the target volume" Geometrically optimized plans had dose points defined between the catheters, while dose-point optimized plans had dose points defined at a plane perpendicular to the implant axis and on the target surface. Each plan was graphically optimized and compared using dose volume indices. Results : Target coverage was suboptimal with coverage index (CI = 0.67 when dose points were defined at the central plane while it was superior when the dose points were defined at the target surface (CI=0.93. The coverage of graphically optimized plans (GrO was similar to non-GrO with dose points defined on surface or perpendicular to the implant axis. A similar pattern was noticed with conformity index (0.61 vs. 0.82. GrO were more conformal and less homogeneous compared to non-GrO. Sum index was superior for dose points defined on the surface of the target and relatively inferior for plans with dose points at other locations (1.35 vs. 1.27. Conclusions : Optimization with dose points defined away from the implant plane and on target results in superior target coverage with optimal values of other indices. GrO offer better target coverage for implants with non-uniform geometry and target volume.

  1. Wind load modeling for topology optimization of continuum structures

    NARCIS (Netherlands)

    Zakhama, R.; Abdalla, M.M.; Gürdal, Z.; Smaoui, H.

    2010-01-01

    Topology optimization of two and three dimensional structures subject to dead and wind loading is considered. The wind loading is introduced into the formulation by using standard expressions for the drag force, and a strategy is devised so that wind pressure is ignored where there is no surface obs

  2. Gearbox design for uncertain load requirements using active robust optimization

    Science.gov (United States)

    Salomon, Shaul; Avigad, Gideon; Purshouse, Robin C.; Fleming, Peter J.

    2016-04-01

    Design and optimization of gear transmissions have been intensively studied, but surprisingly the robustness of the resulting optimal design to uncertain loads has never been considered. Active Robust (AR) optimization is a methodology to design products that attain robustness to uncertain or changing environmental conditions through adaptation. In this study the AR methodology is utilized to optimize the number of transmissions, as well as their gearing ratios, for an uncertain load demand. The problem is formulated as a bi-objective optimization problem where the objectives are to satisfy the load demand in the most energy efficient manner and to minimize production cost. The results show that this approach can find a set of robust designs, revealing a trade-off between energy efficiency and production cost. This can serve as a useful decision-making tool for the gearbox design process, as well as for other applications.

  3. Ant colony Optimization: A Solution of Load balancing in Cloud

    Directory of Open Access Journals (Sweden)

    Ratan Mishra

    2012-05-01

    Full Text Available As the cloud computing is a new style of computing over internet. It has many advantages along with some crucial issues to be resolved in order to improve reliability of cloud environment. These issues are related with the load management, fault tolerance and different security issues in cloud environment. In this paper the main concern is load balancing in cloud computing. The load can be CPU load, memory capacity, delay or network load. Load balancing is the process of distributing the load among various nodes of adistributed system to improve both resource utilization and job response time while also avoiding a situation where some of the nodes are heavily loaded while other nodes are idle or doing very little work. Load balancing ensures that all the processor in the system or every node in the network does approximately the equal amount of work at any instant of time. Many methods to resolve this problem has been came into existence like Particle Swarm Optimization, hash method, genetic algorithms and severalscheduling based algorithms are there. In this paper we are proposing a method based on Ant Colony optimization to resolve the problem of load balancing in cloud environment.

  4. Decision Support System for Optimized Herbicide Dose in Spring Barley

    DEFF Research Database (Denmark)

    Sønderskov, Mette; Kudsk, Per; Mathiassen, Solvejg K;

    2014-01-01

    Crop Protection Online (CPO) is a decision support system, which integrates decision algorithms quantifying the requirement for weed control and a herbicide dose model. CPO was designed to be used by advisors and farmers to optimize the choice of herbicide and dose. The recommendations from CPO...

  5. Aeroelastic optimization design for wing with maneuver load uncertainties

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    An aeroelastic optimization design methodology for air vehicle considering the uncertainties in maneuver load conditions is presented and applied to a structural design process of low-aspect-ratio wing. An aerodynamic load correction model is developed and used to predict the critical load conditions with the perturbations of theoretical linear aerodynamic forces and experimental aerodynamic forces from wind-tunnel test, when concerning the uncertainties in use of theoretical linear and experimental aerodynamic forces. Three objective functions of critical loads are defined. The load evaluations for three wing sections are investigated in four characteristic maneuvers, and the most critical load conditions are confirmed by using the sequential quadratic programming method. On this basis, the aeroelastic optimization design employing the genetic-gradient hybrid algorithm is conducted, in which the objective is to minimize structural mass subject to the constraints of stress, deformation and flutter speed. The resulting optimal structure is heavier than the one simply based on the theoretical linear or experimental aerodynamic forces. However, it is more robust when encountering the critical load conditions in actual flight due to the consideration of uncertainties in aerodynamic forces in the early design phase, thereby, the risk of structural redesign can be reduced.

  6. Optimization of Load Assignment to Boilers in Industrial Boiler Plants

    Institute of Scientific and Technical Information of China (English)

    CAO Jia-cong; QIU Guang; CAO Shuang-hua; LIU Feng-qiang

    2004-01-01

    Along with the increasing importance of sustainable energy, the optimization of load assignment to boilers in an industrial boiler plant becomes one of the major projects for the optimal operation of boiler plants. Optimal load assignment for power systems has been a long-lasting subject, while it is quite new for industrial boiler plants. The existing methods of optimal load assignment for boiler plants are explained and analyzed briefly in the paper. They all need the fuel cost curves of boilers. Thanks to some special features of the curves for industrial boilers, a new model referred to as minimized departure model (MDM) of optimization of load assignment for boiler plants is developed and proposed in the paper. It merely relies upon the accessible data of two typical working conditions to build the model, viz. the working conditions with the highest efficiency of a boiler and with no-load. Explanation of the algorithm of computer program is given, and effort is made so as to determine in advance how many and which boilers are going to work. Comparison between the results using MDM and the results reported in references is carried out, which proves that MDM is preferable and practicable.

  7. A heterogeneous algorithm for PDT dose optimization for prostate

    Science.gov (United States)

    Altschuler, Martin D.; Zhu, Timothy C.; Hu, Yida; Finlay, Jarod C.; Dimofte, Andreea; Wang, Ken; Li, Jun; Cengel, Keith; Malkowicz, S.B.; Hahn, Stephen M.

    2015-01-01

    The object of this study is to develop optimization procedures that account for both the optical heterogeneity as well as photosensitizer (PS) drug distribution of the patient prostate and thereby enable delivery of uniform photodynamic dose to that gland. We use the heterogeneous optical properties measured for a patient prostate to calculate a light fluence kernel (table). PS distribution is then multiplied with the light fluence kernel to form the PDT dose kernel. The Cimmino feasibility algorithm, which is fast, linear, and always converges reliably, is applied as a search tool to choose the weights of the light sources to optimize PDT dose. Maximum and minimum PDT dose limits chosen for sample points in the prostate constrain the solution for the source strengths of the cylindrical diffuser fibers (CDF). We tested the Cimmino optimization procedures using the light fluence kernel generated for heterogeneous optical properties, and compared the optimized treatment plans with those obtained using homogeneous optical properties. To study how different photosensitizer distributions in the prostate affect optimization, comparisons of light fluence rate and PDT dose distributions were made with three distributions of photosensitizer: uniform, linear spatial distribution, and the measured PS distribution. The study shows that optimization of individual light source positions and intensities are feasible for the heterogeneous prostate during PDT. PMID:25914793

  8. A heterogeneous algorithm for PDT dose optimization for prostate

    Science.gov (United States)

    Altschuler, Martin D.; Zhu, Timothy C.; Hu, Yida; Finlay, Jarod C.; Dimofte, Andreea; Wang, Ken; Li, Jun; Cengel, Keith; Malkowicz, S. B.; Hahn, Stephen M.

    2009-02-01

    The object of this study is to develop optimization procedures that account for both the optical heterogeneity as well as photosensitizer (PS) drug distribution of the patient prostate and thereby enable delivery of uniform photodynamic dose to that gland. We use the heterogeneous optical properties measured for a patient prostate to calculate a light fluence kernel (table). PS distribution is then multiplied with the light fluence kernel to form the PDT dose kernel. The Cimmino feasibility algorithm, which is fast, linear, and always converges reliably, is applied as a search tool to choose the weights of the light sources to optimize PDT dose. Maximum and minimum PDT dose limits chosen for sample points in the prostate constrain the solution for the source strengths of the cylindrical diffuser fibers (CDF). We tested the Cimmino optimization procedures using the light fluence kernel generated for heterogeneous optical properties, and compared the optimized treatment plans with those obtained using homogeneous optical properties. To study how different photosensitizer distributions in the prostate affect optimization, comparisons of light fluence rate and PDT dose distributions were made with three distributions of photosensitizer: uniform, linear spatial distribution, and the measured PS distribution. The study shows that optimization of individual light source positions and intensities are feasible for the heterogeneous prostate during PDT.

  9. Statistical optimization of insulin-loaded Pluronic F-127 gels for buccal delivery of basal insulin.

    Science.gov (United States)

    Das, Nilanjana; Madan, Parshotam; Lin, Senshang

    2012-01-01

    The principle of statistical optimization was employed to fabricate insulin-loaded Pluronic F-127 (PF-127) gel formulations having the potential for buccal delivery of basal insulin. A two-level resolution III fractional factorial design was applied to simultaneously evaluate five independent formulation variables: PF-127 concentration, insulin concentration, sodium sulfate concentration, hydroxypropylmethyl cellulose (HPMC) concentration, and presence of sodium glycocholate. The amount of insulin released and permeated from gels as well as gelation time and mucoadhesion force of gels were measured and used as dependent response variables for formulation optimization. Optimization of a gel formulation was achieved by applying constrained optimization via regression analysis. In vitro permeation flux of insulin from the optimized formulation through procine buccal mucosa was 93.17 (±0.058, n = 3) μg/cm(2). Plasma insulin levels following buccal administration of the optimized formulation at 10, 25 and 50 IU/kg to healthy rats were found to be dose dependent and basal insulin levels were maintained at least for 8 h. Furthermore, continuous hypoglycemia for at least 8 h was observed with 89%, 51% and 25% of blood glucose reduction, respectively, for these three doses. The results of this investigation conclude the feasibility of development of optimized buccal insulin-loaded Pluronic F-127 gels for basal insulin delivery.

  10. Safety of Prasugrel Loading Doses in Patients Pre-Loaded With Clopidogrel in the Setting of Primary Percutaneous Coronary Intervention

    DEFF Research Database (Denmark)

    Räber, Lorenz; Klingenberg, Roland; Heg, Dik

    2015-01-01

    OBJECTIVES: The aim of this study was to assess the safety of the concurrent administration of a clopidogrel and prasugrel loading dose in patients undergoing primary percutaneous coronary intervention. BACKGROUND: Prasugrel is one of the preferred P2Y12 platelet receptor antagonists for ST......-segment elevation myocardial infarction patients. The use of prasugrel was evaluated clinically in clopidogrel-naive patients. METHODS: Between September 2009 and October 2012, a total of 2,023 STEMI patients were enrolled in the COMFORTABLE (Comparison of Biomatrix Versus Gazelle in ST-Elevation Myocardial...... Infarction [STEMI]) and the SPUM-ACS (Inflammation and Acute Coronary Syndromes) studies. Patients receiving a prasugrel loading dose were divided into 2 groups: 1) clopidogrel and a subsequent prasugrel loading dose; and 2) a prasugrel loading dose. The primary safety endpoint was Bleeding Academic Research...

  11. Reduced design load basis for ultimate blade loads estimation in multidisciplinary design optimization frameworks

    DEFF Research Database (Denmark)

    Pavese, Christian; Tibaldi, Carlo; Larsen, Torben J.;

    2016-01-01

    The aim is to provide a fast and reliable approach to estimate ultimate blade loads for a multidisciplinary design optimization (MDO) framework. For blade design purposes, the standards require a large amount of computationally expensive simulations, which cannot be efficiently run each cost...... function evaluation of an MDO process. This work describes a method that allows integrating the calculation of the blade load envelopes inside an MDO loop. Ultimate blade load envelopes are calculated for a baseline design and a design obtained after an iteration of an MDO. These envelopes are computed...... for a full standard design load basis (DLB) and a deterministic reduced DLB. Ultimate loads extracted from the two DLBs with the two blade designs each are compared and analyzed. Although the reduced DLB supplies ultimate loads of different magnitude, the shape of the estimated envelopes are similar...

  12. Multiple objective particle swarm optimization technique for economic load dispatch

    Institute of Scientific and Technical Information of China (English)

    ZHAO Bo; CAO Yi-jia

    2005-01-01

    A multi-objective particle swarm optimization (MOPSO) approach for multi-objective economic load dispatch problem in power system is presented in this paper. The economic load dispatch problem is a non-linear constrained multi-objective optimization problem. The proposed MOPSO approach handles the problem as a multi-objective problem with competing and non-commensurable fuel cost, emission and system loss objectives and has a diversity-preserving mechanism using an external memory (call "repository") and a geographically-based approach to find widely different Pareto-optimal solutions. In addition, fuzzy set theory is employed to extract the best compromise solution. Several optimization runs of the proposed MOPSO approach were carried out on the standard IEEE 30-bus test system. The results revealed the capabilities of the proposed MOPSO approach to generate well-distributed Pareto-optimal non-dominated solutions of multi-objective economic load dispatch. Com parison with Multi-objective Evolutionary Algorithm (MOEA) showed the superiority of the proposed MOPSO approach and confirmed its potential for solving multi-objective economic load dispatch.

  13. Determining the optimal dose in the development of anticancer agents.

    Science.gov (United States)

    Mathijssen, Ron H J; Sparreboom, Alex; Verweij, Jaap

    2014-05-01

    Identification of the optimal dose remains a key challenge in drug development. For cytotoxic drugs, the standard approach is based on identifying the maximum tolerated dose (MTD) in phase I trials and incorporating this to subsequent trials. However, this strategy does not take into account important aspects of clinical pharmacology. For targeted agents, the dose-effect relationships from preclinical studies are less obvious, and it is important to change the way these agents are developed to avoid recommending drug doses for different populations without evidence of differential antitumour effects in different diseases. The use of expanded cohorts in phase I trials to better define MTD and refine dose optimization should be further explored together with a focus on efficacy rather than toxicity-based predictions. Another key consideration in dose optimization is related to interindividual pharmacokinetic variability. High variability in intra-individual pharmacokinetics has been observed for many orally-administered drugs, especially those with low bioavailability, which might complicate identification of dose-effect relationships. End-organ dysfunction, interactions with other prescription drugs, herbal supplements, adherence, and food intake can influence pharmacokinetics. It is important these variables are identified during early clinical trials and considered in the development of further phase II and subsequent large-scale phase III studies.

  14. Hybrid Algorithm for Optimal Load Sharing in Grid Computing

    Directory of Open Access Journals (Sweden)

    A. Krishnan

    2012-01-01

    Full Text Available Problem statement: Grid Computing is the fast growing industry, which shares the resources in the organization in an effective manner. Resource sharing requires more optimized algorithmic structure, otherwise the waiting time and response time are increased and the resource utilization is reduced. Approach: In order to avoid such reduction in the performances of the grid system, an optimal resource sharing algorithm is required. In recent days, many load sharing technique are proposed, which provides feasibility but there are many critical issues are still present in these algorithms. Results: In this study a hybrid algorithm for optimization of load sharing is proposed. The hybrid algorithm contains two components which are Hash Table (HT and Distributed Hash Table (DHT. Conclusion: The results of the proposed study show that the hybrid algorithm will optimize the task than existing systems.

  15. Optimal designs for dose response curves with common parameters

    OpenAIRE

    Feller, Chrystel; Schorning, Kirsten; Dette, Holger; Bermann, Georgina; Bornkamp, Björn

    2016-01-01

    A common problem in Phase II clinical trials is the comparison of dose response curves corresponding to different treatment groups. If the effect of the dose level is described by parametric regression models and the treatments differ in the administration frequency (but not in the sort of drug) a reasonable assumption is that the regression models for the different treatments share common parameters. This paper develops optimal design theory for the comparison of different regression models ...

  16. A Study of Load Flow Analysis Using Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Deepak Saini

    2015-01-01

    Full Text Available Load flow study is done to determine the power system static states (voltage magnitudes and voltage angles at each bus to find the steady state working condition of a power system. It is important and most frequently carried out study performed by power utilities for power system planning, optimization, operation and control. In this project a Particle Swarm Optimization (PSO is proposed to solve load flow problem under different loading/ contingency conditions for computing bus voltage magnitudes and angles of the power system. With the increasing size of power system, this is very necessary to finding the solution to maximize the utilization of existing system and to provide adequate voltage support. For this the good voltage profile is must. STATCOM, if placed optimally can be effective in providing good voltage profile and in turn resulting into stable power system. The study presents a hybrid particle swarm based methodology for solving load flow in electrical power systems. Load flow is an electrical engineering well-known problem which provides the system status in the steady-state and is required by several functions performed in power system control centers.

  17. Reduced Design Load Basis for Ultimate Blade Loads Estimation in Multidisciplinary Design Optimization Frameworks

    Science.gov (United States)

    Pavese, Christian; Tibaldi, Carlo; Larsen, Torben J.; Kim, Taeseong; Thomsen, Kenneth

    2016-09-01

    The aim is to provide a fast and reliable approach to estimate ultimate blade loads for a multidisciplinary design optimization (MDO) framework. For blade design purposes, the standards require a large amount of computationally expensive simulations, which cannot be efficiently run each cost function evaluation of an MDO process. This work describes a method that allows integrating the calculation of the blade load envelopes inside an MDO loop. Ultimate blade load envelopes are calculated for a baseline design and a design obtained after an iteration of an MDO. These envelopes are computed for a full standard design load basis (DLB) and a deterministic reduced DLB. Ultimate loads extracted from the two DLBs with the two blade designs each are compared and analyzed. Although the reduced DLB supplies ultimate loads of different magnitude, the shape of the estimated envelopes are similar to the one computed using the full DLB. This observation is used to propose a scheme that is computationally cheap, and that can be integrated inside an MDO framework, providing a sufficiently reliable estimation of the blade ultimate loading. The latter aspect is of key importance when design variables implementing passive control methodologies are included in the formulation of the optimization problem. An MDO of a 10 MW wind turbine blade is presented as an applied case study to show the efficacy of the reduced DLB concept.

  18. Computer simulation of optimal sensor locations in loading identification

    Science.gov (United States)

    Li, Dong-Sheng; Li, Hong-Nan; Guo, Xing L.

    2003-07-01

    A method is presented for the selection of a set of sensor locations from a larger candidate sent for the purpose of structural loading identification. The method ranks the candidate sensor locations according to their effectiveness for identifying the given known loadings. Measurement locations that yield abnormal jumps in identification results or increase the condition number of the frequency response function are removed. The final sensor configuration tends to minimize the error of the loading identification results and the condition number of the frequency response function. The initial candidate set is selected based on the modal kinetic energy distribution that gives a measure of the dynamic contribution of each physical degree freedom to each of the target mode shapes of interest. In addition, excitation location is considered when selecting appropriate response measurement locations. This method was successfully applied to the optimal sensor location selection and loading identification of a uniform cantilever beam in experiment. It is shown that computer simulation is a good way to select the optimal sensor location for loading identification.

  19. An Optimal Load Sharing Technique For Grid Computing

    Directory of Open Access Journals (Sweden)

    D. Ramesh

    2012-01-01

    Full Text Available Problem statement: Grid and Cloud Computing is the fast growing industry, in which the grid computing shares the resources in the organization in an effective manner. Resource sharing requires more optimized algorithmic structure, otherwise the waiting time and response time are increased and the resource utilization is reduced. Approach: In order to avoid such reduction in the performances of the grid system, an optimal resource sharing algorithm is required. The traditional Min-Min algorithm is a simple algorithm that produces a schedule that minimizes the makespan than the other traditional algorithms in the literature. But it fails to produce a load balanced schedule. In our earlier study, a Load Balanced Min-Min (LBMM algorithm is proposed that reduces the makespan and increases the resource utilization. This is further improved through Ant Colony Optimization (ACO based optimization methodology. Results: In recent days, ACO plays a vital role in the discrete optimization problems. The ACO solves many engineering problems and provides optimal result which includes Travelling Salesman Problem, Network Routing and Scheduling. Conclusion: This study proposes an ACO based resource sharing algorithm for effective utilization of grid computing.

  20. Optimal Control Allocation with Load Sensor Feedback for Active Load Suppression, Experiment Development

    Science.gov (United States)

    Miller, Christopher J.; Goodrick, Dan

    2017-01-01

    The problem of control command and maneuver induced structural loads is an important aspect of any control system design. The aircraft structure and the control architecture must be designed to achieve desired piloted control responses while limiting the imparted structural loads. The classical approach is to utilize high structural margins, restrict control surface commands to a limited set of analyzed combinations, and train pilots to follow procedural maneuvering limitations. With recent advances in structural sensing and the continued desire to improve safety and vehicle fuel efficiency, it is both possible and desirable to develop control architectures that enable lighter vehicle weights while maintaining and improving protection against structural damage. An optimal control technique has been explored and shown to achieve desirable vehicle control performance while limiting sensed structural loads. The subject of this paper is the design of the optimal control architecture, and provides the reader with some techniques for tailoring the architecture, along with detailed simulation results.

  1. Optimization of small portable hoist load-capacity model

    Science.gov (United States)

    Tang, Yuanheng; Yin, Hao; Liang, Zuotang; Xu, Cheng

    2017-04-01

    Small Portable Hoist (SPH) is needed in many special occasions; the load-capacity (LC) is one of the most important metrics. There are few researches direct related on SPH and the LC is calculated by Euler's formula in most published related literatures. Because of the SPH's unique, experimental research is carried out on the LC, an optimization of Euler's formula is got by analyzing the effects of wrap angle φ, end tension FB, and relative size of r and R. This optimization is more accurate and it deepens the understanding of the friction between wheel and the bending rope.

  2. Application of chaotic ant swarm optimization in electric load forecasting

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Wei-Chiang [Department of Information Management, Oriental Institute of Technology, 58, Section 2, Sichuan Rd., Panchiao, Taipei County 220 (China)

    2010-10-15

    Support vector regression (SVR) had revealed strong potential in accurate electric load forecasting, particularly by employing effective evolutionary algorithms to determine suitable values of its three parameters. Based on previous research results, however, these employed evolutionary algorithms themselves have several drawbacks, such as converging prematurely, reaching slowly the global optimal solution, and trapping into a local optimum. This investigation presents an SVR-based electric load forecasting model that applied a novel algorithm, namely chaotic ant swarm optimization (CAS), to improve the forecasting performance by searching its suitable parameters combination. The proposed CAS combines with the chaotic behavior of single ant and self-organization behavior of ant colony in the foraging process to overcome premature local optimum. The empirical results indicate that the SVR model with CAS (SVRCAS) results in better forecasting performance than the other alternative methods, namely SVRCPSO (SVR with chaotic PSO), SVRCGA (SVR with chaotic GA), regression model, and ANN model. (author)

  3. Optimized Control Strategy For Over Loaded Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Knudsen, Torben; Wisniewski, Rafal

    2015-01-01

    Abstract Optimized control strategy for overloaded offshore wind turbines Introduction Operation and maintenance cost are an important part of cost of energy especially for offshore wind farms. Typically unplanned service is called for due to detection off excessive loads on components, e...... controller tuning for a given wind turbine. It also enables a very safe and robust comparison between a new control strategy and the present one. Main body of abstract Is it true that power de-rating indeed the best way to reduce loads? The power de-rating approach has the drawback of only indirectly...... and service at offshore location, where accessibility can be problematic. The controller objectives are focused directly on the actual objective like lowering of fore aft fatigue loads, instead of using an indirect objective of de-rating the power production of the wind turbine. This means what the wind...

  4. Graphene-loaded tin oxide nanofibers: optimization and sensing performance

    Science.gov (United States)

    Abideen, Zain Ul; Park, Jae Young; Kim, Hyoun Woo; Kim, Sang Sub

    2017-01-01

    We investigated the gas sensing characteristics of graphene nanosheet (NS)-loaded SnO2 nanofibers (NFs) that were synthesized by a low-cost facile electrospinning process. The sensing performance was characterized as a function of the graphene content with various gases such as C6H6, C7H8, CO, CO2, and H2S. The loading of graphene NSs significantly improved the gas sensing performances of SnO2 NFs. The optimal amount of graphene NSs was found to be 0.5 wt%. We proposed a sensing mechanism for the enhanced sensing performance based on the chemical sensitization of graphene NSs and the charge transfer through the heterointerfaces between graphene NSs and SnO2 nanograins. The results show that graphene NS-loaded SnO2 NFs are a promising sensing material system that can detect hazardous gaseous species.

  5. CT dose minimization using personalized protocol optimization and aggressive bowtie

    Science.gov (United States)

    Wang, Hui; Yin, Zhye; Jin, Yannan; Wu, Mingye; Yao, Yangyang; Tao, Kun; Kalra, Mannudeep K.; De Man, Bruno

    2016-03-01

    In this study, we propose to use patient-specific x-ray fluence control to reduce the radiation dose to sensitive organs while still achieving the desired image quality (IQ) in the region of interest (ROI). The mA modulation profile is optimized view by view, based on the sensitive organs and the ROI, which are obtained from an ultra-low-dose volumetric CT scout scan [1]. We use a clinical chest CT scan to demonstrate the feasibility of the proposed concept: the breast region is selected as the sensitive organ region while the cardiac region is selected as IQ ROI. Two groups of simulations are performed based on the clinical CT dataset: (1) a constant mA scan adjusted based on the patient attenuation (120 kVp, 300 mA), which serves as baseline; (2) an optimized scan with aggressive bowtie and ROI centering combined with patient-specific mA modulation. The results shows that the combination of the aggressive bowtie and the optimized mA modulation can result in 40% dose reduction in the breast region, while the IQ in the cardiac region is maintained. More generally, this paper demonstrates the general concept of using a 3D scout scan for optimal scan planning.

  6. Docetaxel-loaded thermosensitive liquid suppository: optimization of rheological properties.

    Science.gov (United States)

    Yeo, Woo Hyun; Ramasamy, Thiruganesh; Kim, Dong-Wuk; Cho, Hyuk Jun; Kim, Yong-Il; Cho, Kwan Hyung; Yong, Chul Soon; Kim, Jong Oh; Choi, Han-Gon

    2013-12-01

    The main purpose of this work was to optimize the rheological properties of docetaxel (DCT)-loaded thermosensitive liquid suppositories for rectal administration. DCT-loaded liquid suppositories were prepared by a cold method and characterized in terms of physicochemical and viscoelastic properties. Major formulation parameters including poloxamer (P407) and Tween 80 were optimized to adjust the thermogelling and mucoadhesive properties for rectal administration. Notably, the gel strength and mucoadhesive force significantly increased with the increase in these variables. Furthermore, DCT incorporation did not alter the viscoelastic behavior, and the mean particle size of nanomicelles in it was approximately 16 nm with a distinct spherical shape. The formulation existed as liquid at room temperature and transformed into gel at physiological temperature through the reverse gelation phenomenon. Thus, DCT-loaded thermosensitive liquid suppositories [DCT/P407/P188/Tween 80 (0.25/11/15/10 %)] with optimal gel properties were easy to prepare and administer rectally, and might enable the gel to stay in the rectum without getting out from rectum.

  7. A novel approach for optimal chiller loading using particle swarm optimization

    Energy Technology Data Exchange (ETDEWEB)

    Ardakani, A. Jahanbani; Ardakani, F. Fattahi; Hosseinian, S.H. [Department of Electrical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Hafez Avenue, Tehran 15875-4413 (Iran, Islamic Republic of)

    2008-07-01

    This study employs two new methods to solve optimal chiller loading (OCL) problem. These methods are continuous genetic algorithm (GA) and particle swarm optimization (PSO). Because of continuous nature of variables in OCL problem, continuous GA and PSO easily overcome deficiencies in other conventional optimization methods. Partial load ratio (PLR) of the chiller is chosen as the variable to be optimized and consumption power of the chiller is considered as fitness function. Both of these methods find the optimal solution while the equality constraint is exactly satisfied. Some of the major advantages of proposed approaches over other conventional methods can be mentioned as fast convergence, escaping from getting into local optima, simple implementation as well as independency of the solution from the problem. Abilities of proposed methods are examined with reference to an example system. To demonstrate these abilities, results are compared with binary genetic algorithm method. The proposed approaches can be perfectly applied to air-conditioning systems. (author)

  8. Optimization Research of Mine Skip Quantitative Loading System

    Science.gov (United States)

    Wang, Shuang; Hu, Kun; Cheng, Gang; Li, De-yong

    2016-06-01

    The size and change of the impact load of coal material applied to the skip are studied aiming at the quantitative loading system of the skip. Based on the impulse theorem and with reasonable assumption, the calculation formula for impact force of the coal material is deducted and the impact characteristic of the impact force to the quantitative loading system of the skip is analyzed. The process of the coal material falling from quantitative conveyor to skip is analyzed with the discrete element simulation so that the distributed load of the impact force of the coal material at the skip bottom is obtained. The results show that the coal material produces large impact force (687 N) to the skip bottom the moment the coal material falls into the skip, and then the force decreases rapidly to about 245 N and increases gradually during the fluctuation; the impact force applied to the skip bottom increases with the increase of the coal transportation speed and the size of discharging port of the chute, but it is not in direct proportional relationship. The simulation results are basically the same as the experimental results. Finally the optimization parameters of the speed of quantitative conveyor and the size of the discharging port of the chute are searched for so as to improve the capacity of the conveyor and impact load assumed by the skip bottom.

  9. Transdermal film-loaded finasteride microplates to enhance drug skin permeation: Two-step optimization study.

    Science.gov (United States)

    Ahmed, Tarek A; El-Say, Khalid M

    2016-06-10

    The goal was to develop an optimized transdermal finasteride (FNS) film loaded with drug microplates (MIC), utilizing two-step optimization, to decrease the dosing schedule and inconsistency in gastrointestinal absorption. First; 3-level factorial design was implemented to prepare optimized FNS-MIC of minimum particle size. Second; Box-Behnken design matrix was used to develop optimized transdermal FNS-MIC film. Interaction among MIC components was studied using physicochemical characterization tools. Film components namely; hydroxypropyl methyl cellulose (X1), dimethyl sulfoxide (X2) and propylene glycol (X3) were optimized for their effects on the film thickness (Y1) and elongation percent (Y2), and for FNS steady state flux (Y3), permeability coefficient (Y4), and diffusion coefficient (Y5) following ex-vivo permeation through the rat skin. Morphological study of the optimized MIC and transdermal film was also investigated. Results revealed that stabilizer concentration and anti-solvent percent were significantly affecting MIC formulation. Optimized FNS-MIC of particle size 0.93μm was successfully prepared in which there was no interaction observed among their components. An enhancement in the aqueous solubility of FNS-MIC by more than 23% was achieved. All the studied variables, most of their interaction and quadratic effects were significantly affecting the studied variables (Y1-Y5). Morphological observation illustrated non-spherical, short rods, flakes like small plates that were homogeneously distributed in the optimized transdermal film. Ex-vivo study showed enhanced FNS permeation from film loaded MIC when compared to that contains pure drug. So, MIC is a successful technique to enhance aqueous solubility and skin permeation of poor water soluble drug especially when loaded into transdermal films.

  10. Optimal Load Response to Time-of-Use Power Price for Demand Side Management in Denmark

    DEFF Research Database (Denmark)

    Hu, Weihao; Chen, Zhe; Bak-Jensen, Birgitte

    2010-01-01

    -of-use power price for demand side management in order to save the energy costs as much as possible. 3 typical different kinds of loads (industrial load, residential load and commercial load) in Denmark are chosen as study cases. The energy costs decrease up to 9.6% with optimal load response to time......-of-use power price for different loads. Simulation results show that the optimal load response to time-of-use power price for demand side management generates different load profiles and reduces the load peaks. This kind of load patterns may also have significant effects on the power system normal operation....

  11. Optimizing Radiation Doses for Computed Tomography Across Institutions: Dose Auditing and Best Practices.

    Science.gov (United States)

    Demb, Joshua; Chu, Philip; Nelson, Thomas; Hall, David; Seibert, Anthony; Lamba, Ramit; Boone, John; Krishnam, Mayil; Cagnon, Christopher; Bostani, Maryam; Gould, Robert; Miglioretti, Diana; Smith-Bindman, Rebecca

    2017-06-01

    the audit and meeting, head CT doses varied less, although some institutions increased and some decreased mean head CT doses and the proportion above benchmarks. Reviewing institutional doses and sharing dose-optimization best practices resulted in lower radiation doses for chest and abdominal CT and more consistent doses for head CT.

  12. Spatial optimization of watershed management practices for nitrogen load reduction using a modeling-optimization framework.

    Science.gov (United States)

    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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Digital Drug Dosing: Dosing in Drug Assays by Light-Defined Volumes of Hydrogels with Embedded Drug-Loaded Nanoparticles

    DEFF Research Database (Denmark)

    Faralli, Adele; Melander, Fredrik; Larsen, Esben Kjær Unmack;

    2014-01-01

    Polyethylene glycol (PEG)-based hydrogels are widely used for biomedical applications, including matrices for controlled drug release. We present a method for defining drug dosing in screening assays by light-activated cross-linking of PEG-diacrylate hydrogels with embedded drug-loaded liposome...

  14. Optimize Short Term load Forcasting Anomalous Based Feed Forward Backpropagation

    Science.gov (United States)

    Mulyadi, Y.; Abdullah, A. G.; Rohmah, K. A.

    2017-03-01

    This paper contains the Short-Term Load Forecasting (STLF) using artificial neural network especially feed forward back propagation algorithm which is particularly optimized in order to getting a reduced error value result. Electrical load forecasting target is a holiday that hasn’t identical pattern and different from weekday’s pattern, in other words the pattern of holiday load is an anomalous. Under these conditions, the level of forecasting accuracy will be decrease. Hence we need a method that capable to reducing error value in anomalous load forecasting. Learning process of algorithm is supervised or controlled, then some parameters are arranged before performing computation process. Momentum constant a value is set at 0.8 which serve as a reference because it has the greatest converge tendency. Learning rate selection is made up to 2 decimal digits. In addition, hidden layer and input component are tested in several variation of number also. The test result leads to the conclusion that the number of hidden layer impact on the forecasting accuracy and test duration determined by the number of iterations when performing input data until it reaches the maximum of a parameter value.

  15. Finding Multiple Optimal Solutions to Optimal Load Distribution Problem in Hydropower Plant

    Directory of Open Access Journals (Sweden)

    Xinhao Jiang

    2012-05-01

    Full Text Available Optimal load distribution (OLD among generator units of a hydropower plant is a vital task for hydropower generation scheduling and management. Traditional optimization methods for solving this problem focus on finding a single optimal solution. However, many practical constraints on hydropower plant operation are very difficult, if not impossible, to be modeled, and the optimal solution found by those models might be of limited practical uses. This motivates us to find multiple optimal solutions to the OLD problem, which can provide more flexible choices for decision-making. Based on a special dynamic programming model, we use a modified shortest path algorithm to produce multiple solutions to the problem. It is shown that multiple optimal solutions exist for the case study of China’s Geheyan hydropower plant, and they are valuable for assessing the stability of generator units, showing the potential of reducing occurrence times of units across vibration areas.

  16. Aripiprazole loaded poly(caprolactone) nanoparticles: Optimization and in vivo pharmacokinetics.

    Science.gov (United States)

    Sawant, Krutika; Pandey, Abhijeet; Patel, Sneha

    2016-09-01

    In the present investigation, a Quality by Design strategy was applied for formulation and optimization of aripiprazole (APZ) loaded PCL nanoparticles (APNPs) using nanoprecipitation method keeping entrapment efficiency (%EE) and particle size (PS) as critical quality attributes. Establishment of design space was done followed by analysis of its robustness and sensitivity. Characterization of optimized APNPs was done using DSC, FT-IR, PXRD and TEM studies and was evaluated for drug release, hemocompatibility and nasal toxicity. PS, zeta potential and %EE of optimized APNPs were found to be 199.2±5.65nm, -21.4±4.6mV and 69.2±2.34% respectively. In vitro release study showed 90±2.69% drug release after 8h. Nasal toxicity study indicated safety of developed formulation for intranasal administration. APNPs administered via intranasal route facilitated the brain distribution of APZ incorporated with the AUC0→8 in rat brain approximately 2 times higher than that of APNPs administered via intravenous route. Increase in Cmax was observed which might help in dose reduction along with reduction in dose related side effects. The results of the study indicate that intranasally administered APZ loaded PCL NPs can potentially transport APZ via nose to brain and can serve as a non-invasive alternative for the delivery of APZ to brain.

  17. An Optimal Control Scheme to Minimize Loads in Wind Farms

    DEFF Research Database (Denmark)

    Soleimanzadeh, Maryam; Wisniewski, Rafal

    2012-01-01

    This work presents a control algorithm for wind farms that optimizes the power production of the farm and helps to increase the lifetime of wind turbines components. The control algorithm is a centralized approach, and it determines the power reference signals for individual wind turbines...... such that the structural loads of the wind turbines in low frequencies are reduced. The controller is relatively easy to implement on a wind farm, and in here the results of simulating the controller on a small wind farm is presented....

  18. An Optimal Control Scheme to Minimize Loads in Wind Farms

    DEFF Research Database (Denmark)

    Soleimanzadeh, Maryam; Wisniewski, Rafal

    2012-01-01

    This work presents a control algorithm for wind farms that optimizes the power production of the farm and helps to increase the lifetime of wind turbines components. The control algorithm is a centralized approach, and it determines the power reference signals for individual wind turbines...... such that the structural loads of the wind turbines in low frequencies are reduced. The controller is relatively easy to implement on a wind farm, and in here the results of simulating the controller on a small wind farm is presented....

  19. Pallet Optimization of the Heavy Rotary Table Load Carrying System

    Science.gov (United States)

    Atapin, V. G.; Bataev, A. A.

    2016-04-01

    The pallet optimization of the heavy rotary table load-carrying system, which is a part of the multi-purpose machine, is considered in terms of the deterministic and probabilistic models. As a result of optimum design in case of the deterministic model the mass of the pallet is reduced by 35.5 % in comparison with a serial model. The evaluation of the influence of optimization problem limitations on design variables confirms the importance of rigidity criterion in relation to other criteria. Calculation for probabilistic model allows reducing the mass of the construction by 27 % in comparison with the deterministic model. Considering a work piece rigidity on the basis of a conventional work piece of the minimum rigidity (without stiffening ribs etc.) leads to reducing of the pallet mass by 22.3 % in comparison with the deterministic model.

  20. Aripiprazole loaded poly(caprolactone) nanoparticles: Optimization and in vivo pharmacokinetics

    Energy Technology Data Exchange (ETDEWEB)

    Sawant, Krutika; Pandey, Abhijeet; Patel, Sneha

    2016-09-01

    In the present investigation, a Quality by Design strategy was applied for formulation and optimization of aripiprazole (APZ) loaded PCL nanoparticles (APNPs) using nanoprecipitation method keeping entrapment efficiency (%EE) and particle size (PS) as critical quality attributes. Establishment of design space was done followed by analysis of its robustness and sensitivity. Characterization of optimized APNPs was done using DSC, FT-IR, PXRD and TEM studies and was evaluated for drug release, hemocompatibility and nasal toxicity. PS, zeta potential and %EE of optimized APNPs were found to be 199.2 ± 5.65 nm, − 21.4 ± 4.6 mV and 69.2 ± 2.34% respectively. In vitro release study showed 90 ± 2.69% drug release after 8 h. Nasal toxicity study indicated safety of developed formulation for intranasal administration. APNPs administered via intranasal route facilitated the brain distribution of APZ incorporated with the AUC{sub 0→8} in rat brain approximately 2 times higher than that of APNPs administered via intravenous route. Increase in C{sub max} was observed which might help in dose reduction along with reduction in dose related side effects. The results of the study indicate that intranasally administered APZ loaded PCL NPs can potentially transport APZ via nose to brain and can serve as a non-invasive alternative for the delivery of APZ to brain. - Highlights: • It explores intra-nasal route for treatment of schizophrenia. • Quality by Design strategy has been used for optimization and assessesment of design space robustness. • PCL nanoparticles enhance penetration of drug into brain leading to increased C{sub max} and decrease in T{sub max}. • It can act as potential platform for treatment of schizophrenia with decreased dose related toxicities.

  1. Optimization of composite sandwich cover panels subjected to compressive loadings

    Science.gov (United States)

    Cruz, Juan R.

    1991-01-01

    An analysis and design method is presented for the design of composite sandwich cover panels that include the transverse shear effects and damage tolerance considerations. This method is incorporated into a sandwich optimization computer program entitled SANDOP. As a demonstration of its capabilities, SANDOP is used in the present study to design optimized composite sandwich cover panels for for transport aircraft wing applications. The results of this design study indicate that optimized composite sandwich cover panels have approximately the same structural efficiency as stiffened composite cover panels designed to satisfy individual constraints. The results also indicate that inplane stiffness requirements have a large effect on the weight of these composite sandwich cover panels at higher load levels. Increasing the maximum allowable strain and the upper percentage limit of the 0 degree and +/- 45 degree plies can yield significant weight savings. The results show that the structural efficiency of these optimized composite sandwich cover panels is relatively insensitive to changes in core density. Thus, core density should be chosen by criteria other than minimum weight (e.g., damage tolerance, ease of manufacture, etc.).

  2. Optimal Power Management Strategy for Energy Storage with Stochastic Loads

    Directory of Open Access Journals (Sweden)

    Stefano Pietrosanti

    2016-03-01

    Full Text Available In this paper, a power management strategy (PMS has been developed for the control of energy storage in a system subjected to loads of random duration. The PMS minimises the costs associated with the energy consumption of specific systems powered by a primary energy source and equipped with energy storage, under the assumption that the statistical distribution of load durations is known. By including the variability of the load in the cost function, it was possible to define the optimality criteria for the power flow of the storage. Numerical calculations have been performed obtaining the control strategies associated with the global minimum in energy costs, for a wide range of initial conditions of the system. The results of the calculations have been tested on a MATLAB/Simulink model of a rubber tyre gantry (RTG crane equipped with a flywheel energy storage system (FESS and subjected to a test cycle, which corresponds to the real operation of a crane in the Port of Felixstowe. The results of the model show increased energy savings and reduced peak power demand with respect to existing control strategies, indicating considerable potential savings for port operators in terms of energy and maintenance costs.

  3. Single versus multichannel applicator in high-dose-rate vaginal brachytherapy optimized by inverse treatment planning.

    Science.gov (United States)

    Bahadur, Yasir A; Constantinescu, Camelia; Hassouna, Ashraf H; Eltaher, Maha M; Ghassal, Noor M; Awad, Nesreen A

    2015-01-01

    To retrospectively compare the potential dosimetric advantages of a multichannel vaginal applicator vs. a single channel one in intracavitary vaginal high-dose-rate (HDR) brachytherapy after hysterectomy, and evaluate the dosimetric advantage of fractional re-planning. We randomly selected 12 patients with endometrial carcinoma, who received adjuvant vaginal cuff HDR brachytherapy using a multichannel applicator. For each brachytherapy fraction, two inverse treatment plans (for central channel and multichannel loadings) were performed and compared. The advantage of fractional re-planning was also investigated. Dose-volume-histogram (DVH) analysis showed limited, but statistically significant difference (p = 0.007) regarding clinical-target-volume dose coverage between single and multichannel approaches. For the organs-at-risk rectum and bladder, the use of multichannel applicator demonstrated a noticeable dose reduction, when compared to single channel, but statistically significant for rectum only (p = 0.0001). For D2cc of rectum, an average fractional dose of 6.1 ± 0.7 Gy resulted for single channel vs. 5.1 ± 0.6 Gy for multichannel. For D2cc of bladder, an average fractional dose of 5 ± 0.9 Gy occurred for single channel vs. 4.9 ± 0.8 Gy for multichannel. The dosimetric benefit of fractional re-planning was demonstrated: DVH analysis showed large, but not statistically significant differences between first fraction plan and fractional re-planning, due to large inter-fraction variations for rectum and bladder positioning and filling. Vaginal HDR brachytherapy using a multichannel vaginal applicator and inverse planning provides dosimetric advantages over single channel cylinder, by reducing the dose to organs at risk without compromising the target volume coverage, but at the expense of an increased vaginal mucosa dose. Due to large inter-fraction dose variations, we recommend individual fraction treatment plan optimization.

  4. Optimal Intermittent Dose Schedules for Chemotherapy Using Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Nadia ALAM

    2013-08-01

    Full Text Available In this paper, a design method for optimal cancer chemotherapy schedules via genetic algorithm (GA is presented. The design targets the key objective of chemotherapy to minimize the size of cancer tumor after a predefined time with keeping toxic side effects in limit. This is a difficult target to achieve using conventional clinical methods due to poor therapeutic indices of existing anti-cancer drugs. Moreover, there are clinical limitations in treatment administration to maintain continuous treatment. Besides, carefully decided rest periods are recommended to for patient’s comfort. Three intermittent drug scheduling schemes are presented in this paper where GA is used to optimize the dose quantities and timings by satisfying several treatment constraints. All three schemes are found to be effective in total elimination of cancer tumor after an agreed treatment length. The number of cancer cells is found zero at the end of the treatment for all three cases with tolerable toxicity. Finally, two of the schemes, “Fixed interval variable dose (FIVD and “Periodic dose” that are periodic in characteristic have been emphasized due to their additional simplicity in administration along with friendliness to patients. responses to the designed treatment schedules. Therefore the proposed design method is capable of planning effective, simple, patient friendly and acceptable chemotherapy schedules.

  5. A mathematical approach to optimal selection of dose values in the additive dose method of ERP dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, R.B.; Haskell, E.H.; Kenner, G.H. [Utah Univ., Salt Lake City, UT (United States)

    1996-01-01

    Additive dose methods commonly used in electron paramagnetic resonance (EPR) dosimetry are time consuming and labor intensive. We have developed a mathematical approach for determining optimal spacing of applied doses and the number of spectra which should be taken at each dose level. Expected uncertainitites in the data points are assumed to be normally distributed with a fixed standard deviation and linearity of dose response is also assumed. The optimum spacing and number of points necessary for the minimal error can be estimated, as can the likely error in the resulting estimate. When low doses are being estimated for tooth enamel samples the optimal spacing is shown to be a concentration of points near the zero dose value with fewer spectra taken at a single high dose value within the range of known linearity. Optimization of the analytical process results in increased accuracy and sample throughput.

  6. Optimal Control Allocation with Load Sensor Feedback for Active Load Suppression, Flight-Test Performance

    Science.gov (United States)

    Miller, Christopher J.; Goodrick, Dan

    2017-01-01

    The problem of control command and maneuver induced structural loads is an important aspect of any control system design. The aircraft structure and the control architecture must be designed to achieve desired piloted control responses while limiting the imparted structural loads. The classical approach is to utilize high structural margins, restrict control surface commands to a limited set of analyzed combinations, and train pilots to follow procedural maneuvering limitations. With recent advances in structural sensing and the continued desire to improve safety and vehicle fuel efficiency, it is both possible and desirable to develop control architectures that enable lighter vehicle weights while maintaining and improving protection against structural damage. An optimal control technique has been explored and shown to achieve desirable vehicle control performance while limiting sensed structural loads to specified values. This technique has been implemented and flown on the National Aeronautics and Space Administration Full-scale Advanced Systems Testbed aircraft. The flight tests illustrate that the approach achieves the desired performance and show promising potential benefits. The flights also uncovered some important issues that will need to be addressed for production application.

  7. MTR core loading pattern optimization using burnup dependent group constants

    Directory of Open Access Journals (Sweden)

    Iqbal Masood

    2008-01-01

    Full Text Available A diffusion theory based MTR fuel management methodology has been developed for finding superior core loading patterns at any stage for MTR systems, keeping track of burnup of individual fuel assemblies throughout their history. It is based on using burnup dependent group constants obtained by the WIMS-D/4 computer code for standard fuel elements and control fuel elements. This methodology has been implemented in a computer program named BFMTR, which carries out detailed five group diffusion theory calculations using the CITATION code as a subroutine. The core-wide spatial flux and power profiles thus obtained are used for calculating the peak-to-average power and flux-ratios along with the available excess reactivity of the system. The fuel manager can use the BFMTR code for loading pattern optimization for maximizing the excess reactivity, keeping the peak-to-average power as well as flux-ratio within constraints. The results obtained by the BFMTR code have been found to be in good agreement with the corresponding experimental values for the equilibrium core of the Pakistan Research Reactor-1.

  8. Preconditioning is hormesis part II: How the conditioning dose mediates protection: Dose optimization within temporal and mechanistic frameworks.

    Science.gov (United States)

    Calabrese, Edward J

    2016-08-01

    In Part I, hormetic doses of a variety of agents stimulated adaptive responses that conditioned and protected cells against the subsequent toxicity resulting from a second, higher dose (called a challenging dose) of the same or different agents. Herein (Part II), the optimal conditioning (hormetic) doses of many agents are documented, cellular mechanisms and temporal profiles are examined from which the conditioning (hormetic) responses are elicited, and the optimal conditioning doses are compared to the levels at which optimal protection occurs in response to the toxic challenge dose. Entry criteria for study evaluation required a conditioning mechanism-induced endpoint response, an hormetic/biphasic dose response for the protective response following the challenging dose, and a mechanistic assessment of how the conditioning dose afforded protection against a toxic challenging dose. The conditioning dose that demonstrated the largest increase in a mechanism-related conditioning (hormetic) response (i.e., prior to administration of the challenging dose) was the same dose that was optimally protective following the challenging dose. Specific receptor antagonists and/or inhibitors of cell signaling pathways which blocked the induction of conditioning (hormetic) effects during the conditioning period abolished the protective effects following the application of a challenge dose, thus identifying a specific and essential component of the hormetic mechanism. Conditioning responses often had sufficient doses to assess the nature of the dose response. In each of the cases these mechanism-based endpoints displayed an hormetic dose response. The present analysis reveals that hormetic biphasic dose responses were associated with both the conditioning process and the protective effects elicited following the challenging dose. Furthermore, based on optimal dosage, temporal relationships and the known mediating actions of receptor-based and/or cell signaling-based mechanisms

  9. EFFICACY OF SINGLE LOADING DOSE OF MAGNESIUM SULFAT E IN ECLAMPSIA

    Directory of Open Access Journals (Sweden)

    Meenakshi

    2013-02-01

    Full Text Available ABSTRACT: BACKGROUND: Eclampsia is a life threatening condition and it va ries from countries to countries .The incidence in our countr y varies from 5-10%. The first and foremost thing in management of eclampsia is control of conv ulsions. Magnesium sulphate has established itself as the drug of choice for the an ticonvulsant management of eclampsia but the question as to what constitutes the Minimum effecti ve dose remains unanswered which is evident from the different regimens used in clinica l practice. Its narrow therapeutic range mandates that it only be used in the minimum doses which gives efficient control of convulsions and helps in improving maternal and fetal outcome. Ai ms: To study the efficacy and safety of single loading dose of magnesium sulphate in control ling and prevention of recurrence of convulsion in eclampsia, to reduce the adverse affec ts of magnesium sulphate and improve the maternal and fetal outcome with single loading dose . Methods: Prospective study of 100 cases with clinical diagnosis of eclampsia were given sing le loading dose of magnesium sulphate [4 g of 20% IV and 10 g of 50 % IM], there was no mainte nance dose. The effect of singe loading dose of magnesium sulphate in controlling convulsions, th e recurrence rates, toxicity and the maternal and fetal outcome was studied. Results: Th e results showed a favorable outcome with the reduction of the dose and duration of magnesium sulphate therapy. The primary outcomes were comparable with all other regimens in use. Wit h recurrence rate of 9% its efficacy was comparable with the other regimens in use. The cases that were on single dose regimen had a significantly lower incidence of cesarean section w ith up to 74% of the patients having vaginal deliveries. The maternal mortality was 3% and perina tal mortality was 29%. Conclusions: Single loading dose of magnesium sulphate is effecti ve in controlling and prevention of recurrence of convulsions in eclampsia

  10. Load optimal design for a primary test stand facility based on a zero-dimensional load model

    Institute of Scientific and Technical Information of China (English)

    Zhao Hai-Long; Deng Jian-Jun; Wang Gang-Hua; Zou Wen-Kang

    2011-01-01

    In order to couple the numerical simulation of a primary test stand driver with an optimal load design,a zero dimensional wire array load model is designed based on the Saturn load model using PSPICE,which is an upgraded version of the Simulation Program with Integrated Circuit Emphasis (SPICE) designed by the ORCAD Corporation to perform circuit simulations.This paper calculates different load parameters and discusses factors influencing the driving current curve.With appropriate driving current curves chosen,further magneto-hydrodynamic calculations are carried out and discussed to provide the best results for experiments.The suggested optimal load parameters play an important role in experimental load design.

  11. Single Enteral Loading Dose of Phenobarbital for Achieving Its Therapeutic Serum Levels in Neonates

    Science.gov (United States)

    Turhan, Ali H.; Atici, Aytug; Okuyaz, Cetin; Uysal, Sercan

    2010-01-01

    Aim To investigate whether therapeutic serum drug levels may be achieved with a single enteral loading dose of phenobarbital. Methods The study was performed at the Mersin University Hospital in Turkey between April 2004 and August 2006, and included 29 newborn babies with seizure. After the acute treatment of the seizure with midazolam at a dose of 0.1 mg/kg, phenobarbital was administered by orogastric route at a loading dose of 20 mg/kg. Serum phenobarbital concentrations were measured at 0.5, 3, 6, and 12 hours after the loading. Serum phenobarbital levels between 10-30 μg/mL were considered as the therapeutic range. Results The serum phenobarbital levels reached therapeutic values in 9 (31%), 19 (66%), 21 (72%), and 23 (79%) patients at 0.5, 3, 6, and 12 hours after loading, respectively, while they did not reach therapeutic values in 6 patients (21%) after 12 hours. Four of the patients in whom there was no increase in serum phenobarbital levels had hypoxic-ischemic encephalopathy. Conclusion Enteral loading of phenobarbital can achieve therapeutic serum levels in the large majority of newborn babies with seizure and may be safely used in babies with the intact gastrointestinal tract. PMID:20564764

  12. An implementation of particle swarm optimization to evaluate optimal under-voltage load shedding in competitive electricity markets

    Science.gov (United States)

    Hosseini-Bioki, M. M.; Rashidinejad, M.; Abdollahi, A.

    2013-11-01

    Load shedding is a crucial issue in power systems especially under restructured electricity environment. Market-driven load shedding in reregulated power systems associated with security as well as reliability is investigated in this paper. A technoeconomic multi-objective function is introduced to reveal an optimal load shedding scheme considering maximum social welfare. The proposed optimization problem includes maximum GENCOs and loads' profits as well as maximum loadability limit under normal and contingency conditions. Particle swarm optimization (PSO) as a heuristic optimization technique, is utilized to find an optimal load shedding scheme. In a market-driven structure, generators offer their bidding blocks while the dispatchable loads will bid their price-responsive demands. An independent system operator (ISO) derives a market clearing price (MCP) while rescheduling the amount of generating power in both pre-contingency and post-contingency conditions. The proposed methodology is developed on a 3-bus system and then is applied to a modified IEEE 30-bus test system. The obtained results show the effectiveness of the proposed methodology in implementing the optimal load shedding satisfying social welfare by maintaining voltage stability margin (VSM) through technoeconomic analyses.

  13. A linear programming model for optimizing HDR brachytherapy dose distributions with respect to mean dose in the DVH-tail

    Energy Technology Data Exchange (ETDEWEB)

    Holm, Åsa; Larsson, Torbjörn [Department of Mathematics, Linköping University, SE-581 83 Linköping (Sweden); Tedgren, Åsa Carlsson [Department of Medical and Health Sciences, Radiation Physics, Linköping University, SE 581-83 Linköping, Sweden and Swedish Radiation Safety Authority, SE-171 16 Stockholm (Sweden)

    2013-08-15

    Purpose: Recent research has shown that the optimization model hitherto used in high-dose-rate (HDR) brachytherapy corresponds weakly to the dosimetric indices used to evaluate the quality of a dose distribution. Although alternative models that explicitly include such dosimetric indices have been presented, the inclusion of the dosimetric indices explicitly yields intractable models. The purpose of this paper is to develop a model for optimizing dosimetric indices that is easier to solve than those proposed earlier.Methods: In this paper, the authors present an alternative approach for optimizing dose distributions for HDR brachytherapy where dosimetric indices are taken into account through surrogates based on the conditional value-at-risk concept. This yields a linear optimization model that is easy to solve, and has the advantage that the constraints are easy to interpret and modify to obtain satisfactory dose distributions.Results: The authors show by experimental comparisons, carried out retrospectively for a set of prostate cancer patients, that their proposed model corresponds well with constraining dosimetric indices. All modifications of the parameters in the authors' model yield the expected result. The dose distributions generated are also comparable to those generated by the standard model with respect to the dosimetric indices that are used for evaluating quality.Conclusions: The authors' new model is a viable surrogate to optimizing dosimetric indices and quickly and easily yields high quality dose distributions.

  14. Minor Actinides Loading Optimization for Proliferation Resistant Fuel Design - BWR

    Energy Technology Data Exchange (ETDEWEB)

    G. S. Chang; Hongbin Zhang

    2009-09-01

    One approach to address the United States Nuclear Power (NP) 2010 program for the advanced light water reactor (LWR) (Gen-III+) intermediate-term spent fuel disposal need is to reduce spent fuel storage volume while enhancing proliferation resistance. One proposed solution includes increasing burnup of the discharged spent fuel and mixing minor actinide (MA) transuranic nuclides (237Np and 241Am) in the high burnup fuel. Thus, we can reduce the spent fuel volume while increasing the proliferation resistance by increasing the isotopic ratio of 238Pu/Pu. For future advanced nuclear systems, MAs are viewed more as a resource to be recycled, and transmuted to less hazardous and possibly more useful forms, rather than simply disposed of as a waste stream in an expensive repository facility. MAs play a much larger part in the design of advanced systems and fuel cycles, not only as additional sources of useful energy, but also as direct contributors to the reactivity control of the systems into which they are incorporated. A typical boiling water reactor (BWR) fuel unit lattice cell model with UO2 fuel pins will be used to investigate the effectiveness of adding MAs (237Np and/or 241Am) to enhance proliferation resistance and improve fuel cycle performance for the intermediate-term goal of future nuclear energy systems. However, adding MAs will increase plutonium production in the discharged spent fuel. In this work, the Monte-Carlo coupling with ORIGEN-2.2 (MCWO) method was used to optimize the MA loading in the UO2 fuel such that the discharged spent fuel demonstrates enhanced proliferation resistance, while minimizing plutonium production. The axial averaged MA transmutation characteristics at different burnup were compared and their impact on neutronics criticality and the ratio of 238Pu/Pu discussed.

  15. Use of a double computer for load optimization in a smaller regional power utility

    Energy Technology Data Exchange (ETDEWEB)

    Benthin, D.; Wienhold, J.; Woern, G.

    1984-06-18

    Sound frequency point-to-point control has proven its value predominantly in the control of multiple tariff meters and storage heating systems and it is regarded as an effective aid in reducing peak loads. The authors describe the functions and applications of the load optimization system used by the Ueberlandwerk Leinetal GmbH. The experiences recorded during operation can serve as a stimulus for the economical application of load optimization systems.

  16. Optimization of structural parameters for spatial flexible redundant manipulators with maximum ratio of load to mass

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xu-ping; YU Yue-qing

    2005-01-01

    Optimization of structural parameters aimed at improving the load carrying capacity of spatial flexible redundant manipulators is presented in this paper. In order to increase the ratio of load to mass of robots, the cross-sectional parameters and constructional parameters are optimized respectively. The cross-sectional and configurational parameters are optimized simultaneously. The numerical simulation of a 4R spatial manipulator is performed. The results show that the load capacity of robots has been greatly improved through the optimization strategies proposed in this paper.

  17. Optimizing the Loads of multi-player online game Servers using Markov Chains

    DEFF Research Database (Denmark)

    Saeed, Aamir; Olsen, Rasmus Løvenstein; Pedersen, Jens Myrup

    2015-01-01

    , players are flocking to one area, resulting in an overloaded server with decreasing Quality of Service(QoS) for the players. A number of approaches were developed to address these issues, by balancing loads between the over-loaded and under-loaded servers. This paper investigates a new dimension...... that is created due to the load balancing of servers. Load balancing among servers is sensitive to correct status information. The Markov based load prediction was introduced in this paper to predict load of under-loaded servers, based on arrival (μ) and departure (λ) rates of players. The prediction based...... algorithm is proposed to minimize the effect of out dated status information. This approach was compared with normal load status information exchange algorithm. The model presented in this paper does not deal directly with optimizing the load balancing of the server but rather tries to present a new insight...

  18. Carbon-14 background, pathway, and dose optimization analysis

    Energy Technology Data Exchange (ETDEWEB)

    Caffrey, E.; Higley, K. [Oregon State University (United States)

    2014-07-01

    Carbon-14 is radiologically relevant due to its long half-life coupled with its ease of incorporation into the global carbon cycle. The majority of carbon-14 releases from nuclear power plants in the United States are gaseous, and terrestrial samples constitute the primary indicator of increased environmental levels, and thus represent an important pathway for the incorporation of the radionuclide into both human and nonhuman populations. This project was broken into three phases: In phase one, information was summarized on background quantities and production mechanisms of carbon-14 in the general environment and adjacent to nuclear power plants. The second phase involved the review and analysis of nuclear power plant carbon-14 pathways to humans as compared to the United States Nuclear Regulatory Commission's Regulatory Guide 1.109 methodologies (based on ICRP 2), and identified areas where dose calculations could be optimized. Alternative models for calculating plant uptake from atmosphere and transfer in the food chain were investigated, with particular emphasis on models used by countries in the European Union. In phase three, collard green samples grown at three different locations relative to a nuclear power plant (one control garden and two downwind gardens) were evaluated using a Perkin Elmer TriCarb 3180 TR/SL Liquid Scintillation Counter (LSC). Samples were first oven dried and combusted using a Perkin Elmer Model 307 Oxidizer, and activity concentrations were calculated based on the LSC count data. These data were compared to samples analyzed using accelerator mass spectrometry. There was no statistically significant difference in carbon-14 concentrations at the two downwind gardens as compared to the control garden. This research is based on work supported, in part, by the Electrical Power Research Institute (EPRI). The opinions, findings, conclusions, or recommendations expressed herein are those of the author(s) and do not necessarily represent

  19. Feasibility of dose painting using volumetric modulated arc optimization and delivery

    DEFF Research Database (Denmark)

    Korreman, Stine; Ulrich, Silke; Bowen, Stephen

    2010-01-01

    Dose painting strategies are limited by optimization algorithms in treatment planning systems and physical constraints of the beam delivery. We investigate dose conformity using the RapidArc optimizer and beam delivery technique. Furthermore, robustness of the plans with respect to positioning...

  20. Generalized Shape and Gauge Decoupling Load Distribution Optimization Based on IGA for Tandem Cold Mill

    Institute of Scientific and Technical Information of China (English)

    PENG Peng; YANG Quan

    2009-01-01

    Load distribution is the foundation of shape control and gauge control, in which it is necessary to take into account the shape control ability of TCM (tandem cold mill) for strip shape and gauge quality. First, the objective function of generalized shape and gauge decoupling load distribution optimization was established, which considered the rolling force characteristics of the first and last stands in TCM, the relative power, and the TCM shape control ability. Then, IGA (immune genetic algorithm) was used to accomplish this multi-objective load distribution optimization for TCM. After simulation and comparison with the practical load distribution strategy in one tandem cold mill, general-ized shape and gauge decoupling load distribution optimization on the basis of IGA approved good ability of optimizing shape control and gauge control simultaneously.

  1. A technique for multi-dimensional optimization of radiation dose, contrast dose, and image quality in CT imaging

    Science.gov (United States)

    Sahbaee, Pooyan; Abadi, Ehsan; Sanders, Jeremiah; Becchetti, Marc; Zhang, Yakun; Agasthya, Greeshma; Segars, Paul; Samei, Ehsan

    2016-03-01

    The purpose of this study was to substantiate the interdependency of image quality, radiation dose, and contrast material dose in CT towards the patient-specific optimization of the imaging protocols. The study deployed two phantom platforms. First, a variable sized phantom containing an iodinated insert was imaged on a representative CT scanner at multiple CTDI values. The contrast and noise were measured from the reconstructed images for each phantom diameter. Linearly related to iodine-concentration, contrast to noise ratio (CNR), was calculated for different iodine-concentration levels. Second, the analysis was extended to a recently developed suit of 58 virtual human models (5D-XCAT) with added contrast dynamics. Emulating a contrast-enhanced abdominal image procedure and targeting a peak-enhancement in aorta, each XCAT phantom was "imaged" using a CT simulation platform. 3D surfaces for each patient/size established the relationship between iodine-concentration, dose, and CNR. The Sensitivity of Ratio (SR), defined as ratio of change in iodine-concentration versus dose to yield a constant change in CNR was calculated and compared at high and low radiation dose for both phantom platforms. The results show that sensitivity of CNR to iodine concentration is larger at high radiation dose (up to 73%). The SR results were highly affected by radiation dose metric; CTDI or organ dose. Furthermore, results showed that the presence of contrast material could have a profound impact on optimization results (up to 45%).

  2. Analysis of Cumulative Dose to Implanted Pacemaker According to Various IMRT Delivery Methods: Optimal Dose Delivery Versus Dose Reduction Strategy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeong Woo; Hong, Se Mie [Dept. of Radiation Oncology, Konkuk University Medical Center, Seoul (Korea, Republic of)

    2011-11-15

    Cancer patients with implanted cardiac pacemaker occasionally require radiotherapy. Pacemaker may be damaged or malfunction during radiotherapy due to ionizing radiation or electromagnetic interference. Although radiotherapy should be planned to keep the dose to pacemaker as low as possible not to malfunction ideally, current radiation treatment planning (RTP) system does not accurately calculate deposited dose to adjacent field border or area beyond irradiated fields. In terms of beam delivery techniques using multiple intensity modulated fields, dosimetric effect of scattered radiation in high energy photon beams is required to be detailed analyzed based on measurement data. The aim of this study is to evaluate dose discrepancies of pacemaker in a RTP system as compared to measured doses. We also designed dose reduction strategy limited value of 2 Gy for radiation treatment patients with cardiac implanted pacemaker. Total accumulated dose of 145 cGy based on in-vivo dosimetry was satisfied with the recommendation criteria to prevent malfunction of pacemaker in SS technique. However, the 2 mm lead shielder enabled the scattered doses to reduce up to 60% and 40% in the patient and the phantom, respectively. The SS technique with the lead shielding could reduce the accumulated scattered doses less than 100 cGy. Calculated and measured doses were not greatly affected by the beam delivery techniques. In-vivo and measured doses on pacemaker position showed critical dose discrepancies reaching up to 4 times as compared to planned doses in RTP. The current SS technique could deliver lower scattered doses than recommendation criteria, but use of 2 mm lead shielder contributed to reduce scattered doses by 60%. The tertiary lead shielder can be useful to prevent malfunction or electrical damage of implanted pacemakers during radiotherapy. It is required to estimate more accurate scattered doses of the patient or medical device in RTP to design proper dose reduction strategy.

  3. Novel Modeling Framework To Guide Design of Optimal Dosing Strategies for β-Lactamase Inhibitors

    OpenAIRE

    Bhagunde, Pratik; Chang, Kai-Tai; Hirsch, Elizabeth B.; Ledesma, Kimberly R.; Nikolaou, Michael; Tam, Vincent H.

    2012-01-01

    The scarcity of new antibiotics against drug-resistant bacteria has led to the development of inhibitors targeting specific resistance mechanisms, which aim to restore the effectiveness of existing agents. However, there are few guidelines for the optimal dosing of inhibitors. Extending the utility of mathematical modeling, which has been used as a decision support tool for antibiotic dosing regimen design, we developed a novel mathematical modeling framework to guide optimal dosing strategie...

  4. Optimizing dose prescription in stereotactic body radiotherapy for lung tumours using Monte Carlo dose calculation

    NARCIS (Netherlands)

    Widder, Joachim; Hollander, Miranda; Ubbels, Jan F.; Bolt, Rene A.; Langendijk, Johannes A.

    2010-01-01

    Purpose: To define a method of dose prescription employing Monte Carlo (MC) dose calculation in stereotactic body radiotherapy (SBRT) for lung tumours aiming at a dose as low as possible outside of the PTV. Methods and materials: Six typical T1 lung tumours - three small, three large - were construc

  5. Optimization of Monte Carlo dose calculations: The interface problem

    Science.gov (United States)

    Soudentas, Edward

    1998-05-01

    High energy photon beams are widely used for radiation treatment of deep-seated tumors. The human body contains many types of interfaces between dissimilar materials that affect dose distribution in radiation therapy. Experimentally, significant radiation dose perturbations has been observed at such interfaces. The EGS4 Monte Carlo code was used to calculate dose perturbations at boundaries between dissimilar materials (such as bone/water) for 60Co and 6 MeV linear accelerator beams using a UNIX workstation. A simple test of the reliability of a random number generator was also developed. A systematic study of the adjustable parameters in EGS4 was performed in order to minimize calculational artifacts at boundaries. Calculations of dose perturbations at boundaries between different materials showed that there is a 12% increase in dose at water/bone interface, and a 44% increase in dose at water/copper interface. with the increase mainly due to electrons produced in water and backscattered from the high atomic number material. The dependence of the dose increase on the atomic number was also investigated. The clinically important case of using two parallel opposed beams for radiation therapy was investigated where increased doses at boundaries has been observed. The Monte Carlo calculations can provide accurate dosimetry data under conditions of electronic non-equilibrium at tissue interfaces.

  6. Development and Optimization of a Novel Prolonged Release Formulation to Resist Alcohol-Induced Dose Dumping

    OpenAIRE

    Gujjar, Chaitanya Yogananda; Rallabandi, Balaramesha Chary; Gannu, Ramesh; Deulkar, Vallabh Subashrao

    2015-01-01

    Alcohol-induced dose dumping is a serious concern for the orally administered prolonged release dosage forms. The study was designed to optimize the independent variables, propylene glycol alginate (PGA), Eudragit RS PO (ERS) and coating in mucoadhesive quetiapine prolonged release tablets 200 mg required for preventing the alcohol-induced dose dumping. Optimal design based on response surface methodology was employed for the optimization of the composition. The formulations are evaluated for...

  7. Optimal Control Allocation with Load Sensor Feedback for Active Load Suppression

    Science.gov (United States)

    Miller, Christopher

    2017-01-01

    These slide sets describe the OCLA formulation and associated algorithms as a set of new technologies in the first practical application of load limiting flight control utilizing load feedback as a primary control measurement. Slide set one describes Experiment Development and slide set two describes Flight-Test Performance.

  8. Nonlinear optimization of load allocation in a manufacturing system

    Institute of Scientific and Technical Information of China (English)

    GUO Cai-fen; WANG Ning-sheng

    2006-01-01

    Based on the queuing theory, a nonlinear optimization model is proposed in this paper. A novel transformation of optimization variables is devised and the constraints are properly combined so as to make this model into a convex one, from which the Lagrangian function and the KKT conditions are derived. The interiorpoint method for convex optimization is presented here as a computationally efficient tool. Finally, this model is evaluated on a real example, from which such conclusions are drawn that the optimum result can ensure the full utilization of machines and the least amount of WIP in manufacturing systems; the interior-point method for convex optimization needs fewer iterations with significant computational savings. It appears that many non-linear optimization problems in the industrial engineering field would be amenable to this method of solution.

  9. Optimal Control and Biomechanics of Ambulation with Spring-Loaded Crunches

    Directory of Open Access Journals (Sweden)

    Guangyu Liu

    2011-08-01

    Full Text Available Standard underarm or forearm crutches have some drawbacks induced by their rigid legs. Sping‐ loaded crutches can reduce the impact effect. However, whether or not they also improve propulsion is an open problem. We formulate a problem of the optimal performance of spring‐loaded crutches and propose a numerical approach to solve the problem. Then, the numerical optimal values are incorporated to the innovative design of a pair of spring‐loaded crutches. To evaluate the crutchesʹ performance, we have conducted standard biomechanical experiments for a number of male subjects under two conditions: walking with standard crutches and with spring‐loaded crutches. Three dimensional kinematic data and ground reaction force were recorded and analysed. It was observed that optimized spring‐loaded crutches can efficiently propel the crutch walkers, which conforms to the theory.

  10. Optimal bladder filling during high-dose-rate intracavitary brachytherapy for cervical cancer: a dosimetric study

    Science.gov (United States)

    Shetty, Saurabha; Majumder, Dipanjan; Adurkar, Pranjal; Swamidas, Jamema; Engineer, Reena; Chopra, Supriya; Shrivastava, Shyamkishore

    2017-01-01

    Purpose The aim of this study is to compare 3D dose volume histogram (DVH) parameters of bladder and other organs at risk with different bladder filling protocol during high-dose-rate intracavitary brachytherapy (HDR-ICBT) in cervical cancer, and to find optimized bladder volume. Material and methods This dosimetric study was completed with 21 patients who underwent HDR-ICBT with computed tomography/magnetic resonance compatible applicator as a routine treatment. Computed tomography planning was done for each patient with bladder emptied (series 1), after 50 ml (series 2), and 100 ml (series 3) bladder filling with a saline infusion through the bladder catheter. Contouring was done on the Eclipse Planning System. 7 Gy to point A was prescribed with the standard loading patterns. Various 3D DVH parameters including 0.1 cc, 1 cc, 2 cc doses and mean doses to the OAR’s were noted. Paired t-test was performed. Results The mean (± SD) bladder volume was 64.5 (± 25) cc, 116.2 (± 28) cc, and 172.9 (± 29) cc, for series 1, 2, and 3, respectively. The 0.1 cm3,1 cm3, 2 cm3 mean bladder doses for series 1, series 2, and series 3 were 9.28 ± 2.27 Gy, 7.38 ± 1.72 Gy, 6.58 ± 1.58 Gy; 9.39 ± 2.28 Gy, 7.85 ± 1.85 Gy, 7.05 ± 1.59 Gy, and 10.09 ± 2.46 Gy, 8.33 ± 1.75 Gy, 7.6 ± 1.55 Gy, respectively. However, there was a trend towards higher bladder doses in series 3. Similarly, for small bowel dose 0.1 cm3, 1 cm3, and 2 cm3 in series 1, 2, and 3 were 5.44 ± 2.2 Gy, 4.41 ± 1.84 Gy, 4 ± 1.69 Gy; 4.57 ± 2.89 Gy, 3.78 ± 2.21 Gy, 3.35 ± 2.02 Gy, and 4.09 ± 2.38 Gy, 3.26 ± 1.8 Gy, 3.05 ± 1.58 Gy. Significant increase in small bowel dose in empty bladder (series 1) compared to full bladder (series 3) (p = 0.03) was noted. However, the rectal and sigmoid doses were not significantly affected with either series. Conclusions Bladder filling protocol with 50 ml and 100 ml was well tolerated and achieved a reasonably reproducible bladder volume during cervical

  11. The Cytotoxicity, Characteristics, and Optimization of Insulin-loaded Nanoparticles

    Directory of Open Access Journals (Sweden)

    Yasemin Budama-Kilinc

    2017-04-01

    Full Text Available Controlled release systems for insulin are frequent subjects of research, because it is rapidly degraded by proteolytic enzymes in the gastrointestinal tract and minimally absorbed after oral administration. Controlled release systems also provide significant contribution to its stability.  Different techniques are used for the preparation of drug-loaded nanoparticles, and many novel techniques are being developed. The size and morphology of insulin-loaded nanoparticles may vary according to performed techniques, even if the same polymer is used. The aim of this study was to demonstrate the cytotoxicity of insulin loaded nanoparticles and the effect of various synthesis parameters on the particle size, polydispersity index (PdI, loading efficiency, and particle morphology. In the experiments, poly(lactic-co-glycolic acid (PLGA and insulin-loaded PLGA nanoparticles were prepared using the double emulsion (w/o/w method. The characterization of the nanoparticles were performed with a UV spectrometer, the Zeta-sizer system, FTIR spectroscopy, and a scanning probe microscope. Cell toxicity of different concentrations was assayed with MTT methods on L929 fibroblast cells. The optimum size of the insulin-loaded PLGA nanoparticle was obtained with a 96.5% encapsulation efficiency, a 224.5 nm average particle size, and a 0.063 polydispersity index. This study obtained and characterized spherical morphology, determined that the nanoparticles have very low toxicity, and showed the effect of different parameters on particle size and polydispersity. DOI: http://dx.doi.org/10.17807/orbital.v9i1.934 

  12. On the equivalent static loads approach for dynamic response structural optimization

    DEFF Research Database (Denmark)

    Stolpe, Mathias

    2014-01-01

    as the original problem. The optimization theoretical foundation of the algorithm is mainly developed in Park and Kang (J Optim Theory Appl 118(1):191–200, 2003). In that article it is shown, for a certain class of problems, that if the equivalent static loads algorithm terminates then the KKT conditions......The equivalent static loads algorithm is an increasingly popular approach to solve dynamic response structural optimization problems. The algorithm is based on solving a sequence of related static response structural optimization problems with the same objective and constraint functions...

  13. Mechanisms of peer tutoring on optimizing cognitive load during knowledge sharing in learning networks

    NARCIS (Netherlands)

    Hsiao, Amy; Brouns, Francis; Sloep, Peter

    2010-01-01

    Hsiao, Y. P., Brouns, F., & Sloep, P. B. (2010, 15 April). Mechanisms of peer tutoring on optimizing cognitive load during knowledge sharing in learning networks. Presentation at NELLL Colloqium, Heerlen, The Netherlands: Open University of the Netherlands.

  14. A hybrid method for optimal load shedding and improving voltage stability

    Directory of Open Access Journals (Sweden)

    V. Tamilselvan

    2016-03-01

    Full Text Available In this paper, a hybrid method is proposed for reducing the amount of load shedding and voltage collapse. The hybrid method is the combination of Genetic Algorithm (GA and Neural Network (NN. The GA is used by two stages, one is to frame the optimization model and other stage is to generate data set for developing the NN based intelligent load shedding model. The appropriate buses for load shedding are selected based on the sensitivity of minimum eigenvalue of load flow Jacobian with respect to the load shed. The proposed method is implemented in MATLAB working platform and the performance is tested with 6 bus and IEEE 14 bus bench mark system. The result of the proposed hybrid method is compared with the GA based optimization algorithm. The comparison shows that, the proposed method ensures voltage stability with minimum loading shedding.

  15. Optimal switchable load sizing and scheduling for standalone renewable energy systems

    Science.gov (United States)

    Habib, Abdulelah H.; Disfani, Vahid R.; Kleissl, Jan; de Callafon, Raymond A.

    2017-03-01

    The variability of solar energy in off-grid systems dictates the sizing of energy storage systems along with the sizing and scheduling of loads present in the off-grid system. Unfortunately, energy storage may be costly, while frequent switching of loads in the absence of an energy storage system causes wear and tear and should be avoided. Yet, the amount of solar energy utilized should be maximized and the problem of finding the optimal static load size of a finite number of discrete electric loads on the basis of a load response optimization is considered in this paper. The objective of the optimization is to maximize solar energy utilization without the need for costly energy storage systems in an off-grid system. Conceptual and real data for solar photovoltaic power production is provided the input to the off-grid system. Given the number of units, the following analytical solutions and computational algorithms are proposed to compute the optimal load size of each unit: mixed-integer linear programming and constrained least squares. Based on the available solar power profile, the algorithms select the optimal on/off switch times and maximize solar energy utilization by computing the optimal static load sizes. The effectiveness of the algorithms is compared using one year of solar power data from San Diego, California and Thuwal, Saudi Arabia. It is shown that the annual system solar energy utilization is optimized to 73% when using two loads and can be boosted up to 98% using a six load configuration.

  16. Optimization Formulations for the Maximum Nonlinear Buckling Load of Composite Structures

    DEFF Research Database (Denmark)

    Lindgaard, Esben; Lund, Erik

    2011-01-01

    , benchmarked on a number of numerical examples of laminated composite structures for the maximization of the buckling load considering fiber angle design variables. The optimization formulations are based on either linear or geometrically nonlinear analysis and formulated as mathematical programming problems...... solved using gradient based techniques. The developed local criterion is formulated such it captures nonlinear effects upon loading and proves useful for both analysis purposes and as a criterion for use in nonlinear buckling optimization. © 2010 Springer-Verlag....

  17. Optimizing the Design of Connecting Rod under Static and Fatigue Loading

    OpenAIRE

    Om Parkash; Vikas Gupta; Vinod Mittal

    2013-01-01

    The main objective of this work is to re-optimize theexisting design of connecting rod of universal tractor (U650) bychanging some of the design variables. The existing designperforms modelling and evaluates critical regions in theconnecting rod under fatigue loading. In the present work, themodel is developed, analyzed and designed using CATIA 19,PRO-E and ANSYS workbench v12. Optimization of connectingrod is done under same boundary and loading conditions forvariation in the few stress and ...

  18. A hybrid evolutionary algorithm for multi-objective anatomy-based dose optimization in high-dose-rate brachytherapy.

    Science.gov (United States)

    Lahanas, M; Baltas, D; Zamboglou, N

    2003-02-07

    Multiple objectives must be considered in anatomy-based dose optimization for high-dose-rate brachytherapy and a large number of parameters must be optimized to satisfy often competing objectives. For objectives expressed solely in terms of dose variances, deterministic gradient-based algorithms can be applied and a weighted sum approach is able to produce a representative set of non-dominated solutions. As the number of objectives increases, or non-convex objectives are used, local minima can be present and deterministic or stochastic algorithms such as simulated annealing either cannot be used or are not efficient. In this case we employ a modified hybrid version of the multi-objective optimization algorithm NSGA-II. This, in combination with the deterministic optimization algorithm, produces a representative sample of the Pareto set. This algorithm can be used with any kind of objectives, including non-convex, and does not require artificial importance factors. A representation of the trade-off surface can be obtained with more than 1000 non-dominated solutions in 2-5 min. An analysis of the solutions provides information on the possibilities available using these objectives. Simple decision making tools allow the selection of a solution that provides a best fit for the clinical goals. We show an example with a prostate implant and compare results obtained by variance and dose-volume histogram (DVH) based objectives.

  19. A hybrid evolutionary algorithm for multi-objective anatomy-based dose optimization in high-dose-rate brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Lahanas, M [Department of Medical Physics and Engineering, Strahlenklinik, Klinikum Offenbach, 63069 Offenbach (Germany); Baltas, D [Department of Medical Physics and Engineering, Strahlenklinik, Klinikum Offenbach, 63069 Offenbach (Germany); Zamboglou, N [Department of Medical Physics and Engineering, Strahlenklinik, Klinikum Offenbach, 63069 Offenbach (Germany)

    2003-02-07

    Multiple objectives must be considered in anatomy-based dose optimization for high-dose-rate brachytherapy and a large number of parameters must be optimized to satisfy often competing objectives. For objectives expressed solely in terms of dose variances, deterministic gradient-based algorithms can be applied and a weighted sum approach is able to produce a representative set of non-dominated solutions. As the number of objectives increases, or non-convex objectives are used, local minima can be present and deterministic or stochastic algorithms such as simulated annealing either cannot be used or are not efficient. In this case we employ a modified hybrid version of the multi-objective optimization algorithm NSGA-II. This, in combination with the deterministic optimization algorithm, produces a representative sample of the Pareto set. This algorithm can be used with any kind of objectives, including non-convex, and does not require artificial importance factors. A representation of the trade-off surface can be obtained with more than 1000 non-dominated solutions in 2-5 min. An analysis of the solutions provides information on the possibilities available using these objectives. Simple decision making tools allow the selection of a solution that provides a best fit for the clinical goals. We show an example with a prostate implant and compare results obtained by variance and dose-volume histogram (DVH) based objectives.

  20. Optimal fatigue analysis of structures during complex loadings

    Directory of Open Access Journals (Sweden)

    Karaouni Habib

    2016-01-01

    Full Text Available A new framework for high cycle fatigue analysis of metallic structures under complex multi-parameter loadings was here developed. This allows to reduce the analysis on a 2-D window with a characterized one-parameter cyclic loading thanks to an equivalence rule relative to damage between any two loadings. The simplified inelastic analysis introduced by J. Zarka [J. Zarka et al. 1990. A new approach in inelastic analysis of structures. CADLM] was used to find the limit state of the structure. A new design rules for fatigue analysis by utilizing automatic learning systems was successfully performed. A database was built by coupling numerical simulations and experimental results on several welded specimens which are considered as a general structure in the proposed approach. This could be possible by the introduction of an intelligent description of a general fatigue case based on the actual theories and models. A software, FATPRO [M.I. Systems, FatPro, available at http://www.mzintsys.com/our_products_fatpro.html], based on this work has been developed at MZ Intelligent Systems.

  1. Tandem-ring dwell time ratio in Nigeria: dose comparisons of two loading patterns in standard high-dose-rate brachytherapy planning for cervical cancer

    OpenAIRE

    2015-01-01

    Purpose In high-dose-rate (HDR) brachytherapy (BT), the source dwell times and dwell positions are essential treatment planning parameters. An optimal choice of these factors is fundamental to obtain the desired target coverage with the lowest achievable dose to the organs at risk (OARs). This study evaluates relevant dose parameters in cervix brachytherapy in order to assess existing tandem-ring dwell time ratio used at the first HDR BT center in Nigeria, and compare it with an alternative s...

  2. Small Signal Stability Improvement of Power Systems Using Optimal Load Responses in Competitive Electricity Markets

    DEFF Research Database (Denmark)

    Hu, Weihao; Su, Chi; Chen, Zhe;

    2011-01-01

    Since the hourly spot market price is available one day ahead in Denmark, the price could be transferred to the consumers and they may shift some of their loads from high price periods to the low price periods in order to save their energy costs. The optimal load response to an electricity price...... price is proposed. A 17-bus power system with high wind power penetrations, which resembles the Eastern Danish power system, is chosen as the study case. Simulation results show that the optimal load response to electricity prices is an effective measure to improve the small signal stability of power...

  3. Antibiotic elution from acrylic bone cement loaded with high doses of tobramycin and vancomycin.

    Science.gov (United States)

    Slane, Joshua; Gietman, Bradley; Squire, Matthew

    2017-09-06

    Two-stage revision treatment of prosthetic joint infection (PJI) frequently employs the use of a temporary bone cement spacer loaded with multiple antibiotic types. Tobramycin and vancomycin are commonly used antibiotics in cement spacers, however, there is no consensus on the relative concentrations and combinations that should be used. Therefore, the purpose of this study was to investigate the influence of dual antibiotic loading on the total antibiotic elution and compressive mechanical properties of acrylic bone cement. Varying concentrations of tobramycin (0-3 g) and vancomycin (0-3 g) were added either alone or in combination to acrylic cement (Palacos R), resulting in 12 experimental groups. Samples were submerged in 37°C saline for 28 d and sampled at specific time points. The collected eluent was analyzed to determine the cumulative antibiotic release. In addition, the cement's compressive mechanical properties and porosity were characterized. Interestingly, the cement with the highest concentration of antibiotics did not possess the best elution properties. Cement samples containing both 3 g of tobramycin and 2 g vancomycin demonstrated the highest cumulative antibiotic release after 28 d, which was coupled with a significant decrease in the mechanical properties and an increased porosity. The collected data also suggests that tobramycin elutes more effectively than vancomycin from cement. In conclusion, this study demonstrates that high antibiotic loading in cement does not necessarily lead to enhanced antibiotic elution. Clinically this information may be used to optimize cement spacer antibiotic loading so that both duration and amount of antibiotics eluted are optimized. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  4. Selecting radiotherapy dose distributions by means of constrained optimization problems.

    Science.gov (United States)

    Alfonso, J C L; Buttazzo, G; García-Archilla, B; Herrero, M A; Núñez, L

    2014-05-01

    The main steps in planning radiotherapy consist in selecting for any patient diagnosed with a solid tumor (i) a prescribed radiation dose on the tumor, (ii) bounds on the radiation side effects on nearby organs at risk and (iii) a fractionation scheme specifying the number and frequency of therapeutic sessions during treatment. The goal of any radiotherapy treatment is to deliver on the tumor a radiation dose as close as possible to that selected in (i), while at the same time conforming to the constraints prescribed in (ii). To this day, considerable uncertainties remain concerning the best manner in which such issues should be addressed. In particular, the choice of a prescription radiation dose is mostly based on clinical experience accumulated on the particular type of tumor considered, without any direct reference to quantitative radiobiological assessment. Interestingly, mathematical models for the effect of radiation on biological matter have existed for quite some time, and are widely acknowledged by clinicians. However, the difficulty to obtain accurate in vivo measurements of the radiobiological parameters involved has severely restricted their direct application in current clinical practice.In this work, we first propose a mathematical model to select radiation dose distributions as solutions (minimizers) of suitable variational problems, under the assumption that key radiobiological parameters for tumors and organs at risk involved are known. Second, by analyzing the dependence of such solutions on the parameters involved, we then discuss the manner in which the use of those minimizers can improve current decision-making processes to select clinical dosimetries when (as is generally the case) only partial information on model radiosensitivity parameters is available. A comparison of the proposed radiation dose distributions with those actually delivered in a number of clinical cases strongly suggests that solutions of our mathematical model can be

  5. Right dose, right now: using big data to optimize antibiotic dosing in the critically ill.

    Science.gov (United States)

    Elbers, Paul W G; Girbes, Armand; Malbrain, Manu L N G; Bosman, Rob

    2015-01-01

    Antibiotics save lives and are essential for the practice of intensive care medicine. Adequate antibiotic treatment is closely related to outcome. However this is challenging in the critically ill, as their pharmacokinetic profile is markedly altered. Therefore, it is surprising that critical care physicians continue to rely on standard dosing regimens for every patient, regardless of the actual clinical situation. This review outlines the pharmacokinetic and pharmacodynamic principles that underlie the need for individualized and personalized drug dosing. At present, therapeutic drug monitoring may be of help, but has major disadvantages, remains unavailable for most antibiotics and has produced mixed results. We therefore propose the AutoKinetics concept, taking decision support for antibiotic dosing back to the bedside. By direct interaction with electronic patient records, this opens the way for the use of big data for providing the right dose at the right time in each patient.

  6. Therapeutic goal of vitamin D: optimal serum level and dose requirements

    National Research Council Canada - National Science Library

    Lamy, O; Aubry-Rozier, B; Stoll, D

    2012-01-01

    Therapeutic goal of vitamin D: optimal serum level and dose requirements Results of randomized controlled trials and meta-analyses investigating the effect of vitamin D supplementation on falls and fractures are inconsistent...

  7. Dose reduction and optimization studies (ALARA) at nuclear power facilities. [PWR; BWR

    Energy Technology Data Exchange (ETDEWEB)

    Baum, J.W.; Meinhold, C.B.

    1983-01-01

    Brookhaven National Laboratory (BNL) has been commissioned by the Nuclear Regulatory Commission (NRC) to study dose-reduction techniques and effectiveness of as low as reasonably achievable (ALARA) planning at LWR plants. These studies have the following objectives: identify high-dose maintenance tasks; identify dose-reduction techniques; examine incentives for dose reduction; evaluate cost-effectiveness and optimization of dose-reduction techniques; and compile an ALARA handbook on data, engineering modifications, cost-effectiveness calculations, and other information of interest to ALARA practioners.

  8. Load Sharing Multiobjective Optimization Design of a Split Torque Helicopter Transmission

    Directory of Open Access Journals (Sweden)

    Chenxi Fu

    2015-01-01

    Full Text Available Split torque designs can offer significant advantages over the traditional planetary designs for helicopter transmissions. However, it has two unique properties, gap and phase differences, which result in the risk of unequal load sharing. Various methods have been proposed to eliminate the effect of gap and promote load sharing to a certain extent. In this paper, system design parameters will be optimized to change the phase difference, thereby further improving load sharing. A nonlinear dynamic model is established to measure the load sharing with dynamic mesh forces quantitatively. Afterwards, a multiobjective optimization of a reference split torque design is conducted with the promoting of load sharing property, lightweight, and safety considered as the objectives. The load sharing property, which is measured by load sharing coefficient, is evaluated under multiple operating conditions with dynamic analysis method. To solve the multiobjective model with NSGA-II, an improvement is done to overcome the problem of time consuming. Finally, a satisfied optimal solution is picked up as the final design from the Pareto optimal front, which achieves improvements in all the three objectives compared with the reference design.

  9. Optimal design of structures for earthquake loads by a hybrid RBF-BPSO method

    Institute of Scientific and Technical Information of China (English)

    Eysa Salajegheh; Saeed Gholizadeh; Mohsen Khatibina

    2008-01-01

    The optimal seismic design of structures requires that time history analyses (THA) be carried out repeatedly. This makes the optimal design process inefficient, in particular, if an evolutionary algorithm is used. To reduce the overall time required for structural optimization, two artificial intelligence strategies are employed. In the first strategy, radial basis function (RBF) neural networks are used to predict the time history responses of structures in the optimization flow. In the second strategy, a binary particle swarm optimization (BPSO) is used to find the optimum design. Combining the RBF and BPSO, a hybrid RBF-BPSO optimization method is proposed in this paper, which achieves fast optimization with high computational performance. Two examples are presented and compared to determine the optimal weight of structures under earthquake loadings using both exact and approximate analyses. The numerical results demonstrate the computational advantages and effectiveness of the proposed hybrid RBF-BPSO optimization method for the seismic design of structures.

  10. Coordinated Optimization of Distributed Energy Resources and Smart Loads in Distribution Systems: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Rui; Zhang, Yingchen

    2016-08-01

    Distributed energy resources (DERs) and smart loads have the potential to provide flexibility to the distribution system operation. A coordinated optimization approach is proposed in this paper to actively manage DERs and smart loads in distribution systems to achieve the optimal operation status. A three-phase unbalanced Optimal Power Flow (OPF) problem is developed to determine the output from DERs and smart loads with respect to the system operator's control objective. This paper focuses on coordinating PV systems and smart loads to improve the overall voltage profile in distribution systems. Simulations have been carried out in a 12-bus distribution feeder and results illustrate the superior control performance of the proposed approach.

  11. Coordinated Optimization of Distributed Energy Resources and Smart Loads in Distribution Systems

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Rui; Zhang, Yingchen

    2016-11-14

    Distributed energy resources (DERs) and smart loads have the potential to provide flexibility to the distribution system operation. A coordinated optimization approach is proposed in this paper to actively manage DERs and smart loads in distribution systems to achieve the optimal operation status. A three-phase unbalanced Optimal Power Flow (OPF) problem is developed to determine the output from DERs and smart loads with respect to the system operator's control objective. This paper focuses on coordinating PV systems and smart loads to improve the overall voltage profile in distribution systems. Simulations have been carried out in a 12-bus distribution feeder and results illustrate the superior control performance of the proposed approach.

  12. Optimization of structures subjected to dynamic load: deterministic and probabilistic methods

    Directory of Open Access Journals (Sweden)

    Élcio Cassimiro Alves

    Full Text Available Abstract This paper deals with the deterministic and probabilistic optimization of structures against bending when submitted to dynamic loads. The deterministic optimization problem considers the plate submitted to a time varying load while the probabilistic one takes into account a random loading defined by a power spectral density function. The correlation between the two problems is made by one Fourier Transformed. The finite element method is used to model the structures. The sensitivity analysis is performed through the analytical method and the optimization problem is dealt with by the method of interior points. A comparison between the deterministic optimisation and the probabilistic one with a power spectral density function compatible with the time varying load shows very good results.

  13. STACKING SEQUENCE OPTIMIZATION OF LAMINATED COMPOSITE CYLINDER SHELL FOR MAXIMAL BUCKLING LOAD

    Institute of Scientific and Technical Information of China (English)

    TANG Qian; LIAO Xiaoyun; GAO Zhan

    2008-01-01

    A new optimization method for the optimization of stacking of composite glass fiber laminates is developed. The fiber orientation and angle of the layers of the cylindrical shells are sought considering the buckling load. The proposed optimization algorithm applies both finite element analysis and the mode-pursuing sampling (MPS)method. The algorithms suggest the optimal stacking sequence for achieving the maximal buckling load. The procedure is implemented by integrating ANSYS and MATLAB. The stacking sequence designing for the symmetric angle-ply three-layered and five-layered composite cylinder shells is presented to illustrate the optimization process, respectively. Compared with the genetic algorithms, the proposed optimization method is much faster and efficient for composite staking sequence plan.

  14. Robust Topology Optimization Based on Stochastic Collocation Methods under Loading Uncertainties

    Directory of Open Access Journals (Sweden)

    Qinghai Zhao

    2015-01-01

    Full Text Available A robust topology optimization (RTO approach with consideration of loading uncertainties is developed in this paper. The stochastic collocation method combined with full tensor product grid and Smolyak sparse grid transforms the robust formulation into a weighted multiple loading deterministic problem at the collocation points. The proposed approach is amenable to implementation in existing commercial topology optimization software package and thus feasible to practical engineering problems. Numerical examples of two- and three-dimensional topology optimization problems are provided to demonstrate the proposed RTO approach and its applications. The optimal topologies obtained from deterministic and robust topology optimization designs under tensor product grid and sparse grid with different levels are compared with one another to investigate the pros and cons of optimization algorithm on final topologies, and an extensive Monte Carlo simulation is also performed to verify the proposed approach.

  15. A novel load balanced energy conservation approach in WSN using biogeography based optimization

    Science.gov (United States)

    Kaushik, Ajay; Indu, S.; Gupta, Daya

    2017-09-01

    Clustering sensor nodes is an effective technique to reduce energy consumption of the sensor nodes and maximize the lifetime of Wireless sensor networks. Balancing load of the cluster head is an important factor in long run operation of WSNs. In this paper we propose a novel load balancing approach using biogeography based optimization (LB-BBO). LB-BBO uses two separate fitness functions to perform load balancing of equal and unequal load respectively. The proposed method is simulated using matlab and compared with existing methods. The proposed method shows better performance than all the previous works implemented for energy conservation in WSN

  16. Optimal Topology of Aircraft Rib and Spar Structures under Aeroelastic Loads

    Science.gov (United States)

    Stanford, Bret K.; Dunning, Peter D.

    2014-01-01

    Several topology optimization problems are conducted within the ribs and spars of a wing box. It is desired to locate the best position of lightening holes, truss/cross-bracing, etc. A variety of aeroelastic metrics are isolated for each of these problems: elastic wing compliance under trim loads and taxi loads, stress distribution, and crushing loads. Aileron effectiveness under a constant roll rate is considered, as are dynamic metrics: natural vibration frequency and flutter. This approach helps uncover the relationship between topology and aeroelasticity in subsonic transport wings, and can therefore aid in understanding the complex aircraft design process which must eventually consider all these metrics and load cases simultaneously.

  17. Active load sharing technique for on-line efficiency optimization in DC microgrids

    DEFF Research Database (Denmark)

    Sanseverino, E. Riva; Zizzo, G.; Boscaino, V.

    2017-01-01

    , is created to store the real efficiencies of the converters taking into account components tolerances. A MATLAB/Simulink model of the DC distribution network has been set up and a Genetic Algorithm has been employed for the global efficiency optimization. Simulation results are shown to validate the proposed......-DC converters, is modeled. An active load sharing technique is proposed for the on-line optimization of the global efficiency of the DC distribution network. The algorithm aims at the instantaneous efficiency optimization of the whole DC network, based on the on-line load current sampling. A Look Up Table...

  18. Vehicle Hull Shape Optimization for Minimum Weight Under Blast Loading

    Science.gov (United States)

    2013-03-01

    Tovar (1)**   Matthew  P.  Castanier(4),  Madanmohan  V...MINIMUN WEIGHT UNDER BLAST LOADING 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) J Israel; H Tan; J Goetz; A Tovar ...past  by  Goetz  and   Tovar  to  develop  two-­‐material  topologies  for  blast  mitigation  [1]  ,  but  

  19. Anatomy-based three-dimensional dose optimization in brachytherapy using multiobjective genetic algorithms.

    Science.gov (United States)

    Lahanas, M; Baltas, D; Zamboglou, N

    1999-09-01

    In conventional dose optimization algorithms, in brachytherapy, multiple objectives are expressed in terms of an aggregating function which combines individual objective values into a single utility value, making the problem single objective, prior to optimization. A multiobjective genetic algorithm (MOGA) was developed for dose optimization based on an a posteriori approach, leaving the decision-making process to a planner and offering a representative trade-off surface of the various objectives. The MOGA provides a flexible search engine which provides the maximum of information for a decision maker. Tests performed with various treatment plans in brachytherapy have shown that MOGA gives solutions which are superior to those of traditional dose optimization algorithms. Objectives were proposed in terms of the COIN distribution and differential volume histograms, taking into account patient anatomy in the optimization process.

  20. Optimization of the Loading Process of the QUIC Magnetic Trap for the Experiment of Bose-Einstein Condensation

    Institute of Scientific and Technical Information of China (English)

    CHEN Shuai; ZHOU Xiao-Ji; YANG Fan; XIA Lin; WANG Yi-Qiu; CHEN Xu-Zong

    2004-01-01

    @@ The magnetic quadrupole-Ioffe configuration (QUIC) trap in our Bose-Einstein condensation experiment is introduced. The magnetic trap loading process after laser cooling is analysed and the optimization of the loading process is studied experimentally. Calculation of the magnetic field explains the loss of the atoms during the loading process of the QUIC trap. The number of atoms loaded in the QUIC trap is increased by 40%o after optimization in comparison with the normal loading process.

  1. Towards optimal dosing of coumarin derivatives: the role of pharmacogenetics

    NARCIS (Netherlands)

    van Schie, R.M.F.

    2013-01-01

    Coumarin derivatives are effective in the prevention and treatment of thromboembolic diseases. Examples of indications are atrial fibrillation and venous thromboembolism. Although coumarins are on the market for decades, it is still challenging to find the optimal dosage for each patient since couma

  2. On Topology Optimization of Inertia Driven Dosing Units

    DEFF Research Database (Denmark)

    Andreasen, Casper Schousboe

    2016-01-01

    are modeled using the steady state incompressible Navier-Stokes equations and the two fluids are considered havingthe same properties. A Brinkman penalization term is added to the governing equations such that a control problem of the flow topologyis obtained. Optimized component geometries for a range...

  3. Optimal antiproteinuric dose of losartan in nondiabetic patients with nephrotic range proteinuria

    NARCIS (Netherlands)

    Laverman, GD; Henning, RH; de Jong, PE; Navis, G; de Zeeuw, D

    2001-01-01

    Although the antiproteinuric response to antihypertensive treatment is the main predictor of renoprotective efficacy in long-term renal disease, to date, dose-finding studies of anti hypertensives have been based only on blood pressure. We aimed to find the optimal antiproteinuric dose of the angiot

  4. Optimal Cooling Load and COP Relationship of a Four-Heat-Reservoir Endoreversible Absorption Refrigeration Cycle

    Directory of Open Access Journals (Sweden)

    Chih Wu

    2004-06-01

    Full Text Available Abstract: On the basis of a four-heat-reservoir endoreversible absorption refrigeration cycle model, another linear heat transfer law [i.e., the heat-flux] is adopted, the fundamental optimal relation between the coefficient of performance (COP and the cooling load, as well as the maximum cooling load and the corresponding COP of the cycle coupled to constant-temperature heat reservoirs are derived by using finite-time thermodynamics or thermodynamic optimization. The optimal distribution of the heat-transfer surface areas is also obtained. Moreover, the effects of the cycle parameters on the COP and the cooling load of the cycle are studied by detailed numerical examples. The results obtained herein are of importance to the optimal design and performance improvement of an absorption refrigeration cycle.

  5. A randomized controlled trial of vitamin D dosing strategies after acute hip fracture: No advantage of loading doses over daily supplementation

    Directory of Open Access Journals (Sweden)

    Farrauto Leonardo

    2011-06-01

    Full Text Available Abstract Background There remains uncertainty regarding the appropriate therapeutic management of hip fracture patients. The primary aim of our study was to examine whether large loading doses in addition to daily vitamin D offered any advantage over a simple daily low-dose vitamin D regimen for increasing vitamin D levels. Methods In this randomized controlled study, patients over age 50 with an acute fragility hip fracture were enrolled from two hospital sites in Ontario, Canada. Participants were randomized to one of three loading dose groups: placebo; 50,000 IU vitamin D2; or 100,000 IU D2. Following a placebo/loading dose, all patients received a daily tablet of 1,000 IU vitamin D3 for 90 days. Serum 25-hydroxy vitamin D (25-OHD was measured at baseline, discharge from acute care (approximately 4-weeks, and 3-months. Results Sixty-five patients were enrolled in the study (44% male. An immediate rise in 25-OHD occurred in the 100,000 group, however there were no significant differences in 25-OHD between the placebo, 50,000 and 100,000 loading dose groups after 4-weeks (69.3, 84.5, 75.6 nmol/L, p = 0.15 and 3-months (86.7, 84.2, 73.3 nmol/L, p = 0.09, respectively. At the end of the study, approximately 75% of the placebo and 50,000 groups had reached the target therapeutic range (75 nmol/L, and 44% of the 100,000 group. Conclusions In correcting vitamin D insufficiency/deficiency in elderly patients with hip fracture, our findings suggest that starting with a lower daily dose of Vitamin D3 achieved similar results as providing an additional large loading dose of Vitamin D2. At the end of the study, all three groups were equally effective in attaining improvement in 25-OHD levels. Given that a daily dose of 1,000 IU vitamin D3 (with or without a loading dose resulted in at least 25% of patients having suboptimal vitamin D status, patients with acute hip fracture may benefit from a higher daily dose of vitamin D. Trial registration Clinical

  6. Optimization of a Low Heat Load Turbine Nozzle Guide Vane

    Science.gov (United States)

    2006-03-01

    by Durbin et al. [31] to define optimally contoured endwalls for a one-blade, two-passage infinite cascade for turbulence modeling studies...Baldin-Lomax algebraic turbulence model. The code grid zones included two overset grids, an O and an H grid. The grids are used to make the...1984, pp. 173-182. [31] Durbin , P., Eaton, J., Laskowski, G., and Vicharelli, A., “Transonic Cascade Measurements to Support Turbulence Modeling

  7. Implementation of spot scanning dose optimization and dose calculation for helium ions in Hyperion

    DEFF Research Database (Denmark)

    Fuchs, Hermann; Alber, Markus; Schreiner, Thomas

    2015-01-01

    and integrated into the treatment planning system Hyperion. METHODS: Current knowledge on RBE of (4)He together with linear energy transfer considerations motivated an empirical depth-dependent "zonal" RBE model. In the plateau region, a RBE of 1.0 was assumed, followed by an increasing RBE up to 2...... doses resulted in a γ mean of 0.3, with 3.4% of the values above 1 and γ 1% of 1.5 and better. Treatment plan evaluation showed comparable planning target volume coverage for both particles, with slightly increased coverage for (4)He. Organ at risk (OAR) doses were generally reduced using (4)He, some...

  8. Implementation of spot scanning dose optimization and dose calculation for helium ions in Hyperion

    Energy Technology Data Exchange (ETDEWEB)

    Fuchs, Hermann, E-mail: hermann.fuchs@meduniwien.ac.at [Department of Radiation Oncology, Division of Medical Radiation Physics, Medical University of Vienna/AKH Vienna, Vienna 1090, Austria and Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna 1090 (Austria); Alber, Markus [Department for Oncology, Aarhus University Hospital, Aarhus 8000 (Denmark); Schreiner, Thomas [PEG MedAustron, Wiener Neustadt 2700 (Austria); Georg, Dietmar [Department of Radiation Oncology, Division of Medical Radiation Physics, Medical University of Vienna/AKH Vienna, Vienna 1090 (Austria); Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna 1090 (Austria); Comprehensive Cancer Center, Medical University of Vienna/AKH Vienna, Vienna 1090 (Austria)

    2015-09-15

    Purpose: Helium ions ({sup 4}He) may supplement current particle beam therapy strategies as they possess advantages in physical dose distribution over protons. To assess potential clinical advantages, a dose calculation module accounting for relative biological effectiveness (RBE) was developed and integrated into the treatment planning system Hyperion. Methods: Current knowledge on RBE of {sup 4}He together with linear energy transfer considerations motivated an empirical depth-dependent “zonal” RBE model. In the plateau region, a RBE of 1.0 was assumed, followed by an increasing RBE up to 2.8 at the Bragg-peak region, which was then kept constant over the fragmentation tail. To account for a variable proton RBE, the same model concept was also applied to protons with a maximum RBE of 1.6. Both RBE models were added to a previously developed pencil beam algorithm for physical dose calculation and included into the treatment planning system Hyperion. The implementation was validated against Monte Carlo simulations within a water phantom using γ-index evaluation. The potential benefits of {sup 4}He based treatment plans were explored in a preliminary treatment planning comparison (against protons) for four treatment sites, i.e., a prostate, a base-of-skull, a pediatric, and a head-and-neck tumor case. Separate treatment plans taking into account physical dose calculation only or using biological modeling were created for protons and {sup 4}He. Results: Comparison of Monte Carlo and Hyperion calculated doses resulted in a γ{sub mean} of 0.3, with 3.4% of the values above 1 and γ{sub 1%} of 1.5 and better. Treatment plan evaluation showed comparable planning target volume coverage for both particles, with slightly increased coverage for {sup 4}He. Organ at risk (OAR) doses were generally reduced using {sup 4}He, some by more than to 30%. Improvements of {sup 4}He over protons were more pronounced for treatment plans taking biological effects into account. All

  9. Optimized load sharing control by means of thermal reliability management

    DEFF Research Database (Denmark)

    Nesgaard, Carsten; Andersen, Michael Andreas E.

    2004-01-01

    With new applications for high-current low-output voltage power systems emerging nearly every day the need for new and cost-efficient power system designs is a matter of course. As output voltage levels continue to decrease an approach that seems more and more attractive is the implementation...... that each converter in the configuration delivers its share of the total output power. In other words parallel-operation of multiple converters is employed when specifications require a highly reliable system, designable within a very short time frame and at low costs. However, to make full use...... of distributed power configurations with point-of-load power conversion. This technique distributes a high voltage to all parts of the system, thus minimizing the voltage drops throughout the distribution network. However, this configuration only solves the problem of power losses in the distribution network...

  10. Impact of dose calculation accuracy during optimization on lung IMRT plan quality.

    Science.gov (United States)

    Li, Ying; Rodrigues, Anna; Li, Taoran; Yuan, Lulin; Yin, Fang-Fang; Wu, Q Jackie

    2015-01-08

    The purpose of this study was to evaluate the effect of dose calculation accuracy and the use of an intermediate dose calculation step during the optimization of intensity-modulated radiation therapy (IMRT) planning on the final plan quality for lung cancer patients. This study included replanning for 11 randomly selected free-breathing lung IMRT plans. The original plans were optimized using a fast pencil beam convolution algorithm. After optimization, the final dose calculation was performed using the analytical anisotropic algorithm (AAA). The Varian Treatment Planning System (TPS) Eclipse v11, includes an option to perform intermediate dose calculation during optimization using the AAA. The new plans were created using this intermediate dose calculation during optimization with the same planning objectives and dose constraints as in the original plan. Differences in dosimetric parameters for the planning target volume (PTV) dose coverage, organs-at-risk (OARs) dose sparing, and the number of monitor units (MU) between the original and new plans were analyzed. Statistical significance was determined with a p-value of less than 0.05. All plans were normalized to cover 95% of the PTV with the prescription dose. Compared with the original plans, the PTV in the new plans had on average a lower maximum dose (69.45 vs. 71.96Gy, p = 0.005), a better homogeneity index (HI) (0.08 vs. 0.12, p = 0.002), and a better conformity index (CI) (0.69 vs. 0.59, p = 0.003). In the new plans, lung sparing was increased as the volumes receiving 5, 10, and 30 Gy were reduced when compared to the original plans (40.39% vs. 42.73%, p = 0.005; 28.93% vs. 30.40%, p = 0.001; 14.11%vs. 14.84%, p = 0.031). The volume receiving 20 Gy was not significantly lower (19.60% vs. 20.38%, p = 0.052). Further, the mean dose to the lung was reduced in the new plans (11.55 vs. 12.12 Gy, p = 0.024). For the esophagus, the mean dose, the maximum dose, and the volumes receiving 20 and 60 Gy were lower in

  11. Load Reconstruction Technique Using D-Optimal Design and Markov Parameters

    Directory of Open Access Journals (Sweden)

    Deepak K. Gupta

    2015-01-01

    Full Text Available This paper develops a technique for identifying dynamic loads acting on a structure based on impulse response of the structure, also referred to as the system Markov parameters, and structure response measured at optimally placed sensors on the structure. Inverse Markov parameters are computed from the forward Markov parameters using a linear prediction algorithm and have the roles of input and output reversed. The applied loads are then reconstructed by convolving the inverse Markov parameters with the system response to the loads measured at optimal locations on the structure. The structure essentially acts as its own load transducer. It has been noted that the computation of inverse Markov parameters, like most other inverse problems, is ill-conditioned which causes their convolution with the measured response to become quite sensitive to errors in system modeling and response measurements. The computation of inverse Markov parameters (and thereby the quality of load estimates depends on the locations of sensors on the structure. To ensure that the computation of inverse Markov parameters is well-conditioned, a solution approach, based on the construction of D-optimal designs, is presented to determine the optimal sensor locations such that precise load estimates are obtained.

  12. Dosing of ACE inhibitors in left ventricular dysfunction : Does current clinical dosing provide optimal benefit?

    NARCIS (Netherlands)

    Pinto, YM; van Geel, PP; Alkfaji, H; van Veldhuisen, DJ; van Gilst, WH

    1999-01-01

    In the present review, we discuss the role of clinical dosing of angiotensin converting enzyme (ACE) inhibitors in the treatment of left ventricular dysfunction. Although the precise mechanism of action of ACE inhibitors is still unresolved, the clinical efficacy of ACE inhibitors in the treatment o

  13. Dose optimization in nuclear medicine using mathematical simulation

    CERN Document Server

    Souza, J F

    2001-01-01

    The aim of this work was to determine the dose received by a patient who benefited from a bone scintigraphy and obtain data concerning the acquisition of the images, with the goal reducing the administered activity for such a procedure. In order to determine such doses, it is necessary to make use of a biokinetic model concerning the specific radiopharmaceutical (in our case, 99mTc-MDP) Building up a model or validating a pre-existing one requires in vivo and in vitro measurements of the activities present in the organisms, as determined at different times after intake. Our in vitro measurements were obtained by means of urine samples from 20 patients. Our in vivo data were obtained directly from irradiated human bone, by means of a scintillation camera and a tibia / fibula phantom (65 patients). We studied the following parameters, concerning a conventional bone scintigraphy (125 patients): injected activity, lapsed time between injection and acquisition, number of counts at the first scanning, age and body ...

  14. Collimator angle influence on dose distribution optimization for vertebral metastases using volumetric modulated arc therapy

    Energy Technology Data Exchange (ETDEWEB)

    Mancosu, Pietro; Cozzi, Luca; Fogliata, Antonella; Lattuada, Paola; Reggiori, Giacomo; Cantone, Marie Claire; Navarria, Pierina; Scorsetti, Marta [Department of Radiation Oncology, IRCCS Istituto Clinico Humanitas, Milano (Rozzano) 20089 (Italy); Medical Physics Unit, Oncology Institute of Southern Switzerland, Bellinzona 6504 (Switzerland); Department of Radiation Oncology, IRCCS Istituto Clinico Humanitas, Milano (Rozzano) 20089 (Italy); Department of Physics, Universita Degli Studi di Milano, Milano 20133 (Italy); Department of Radiation Oncology, IRCCS Istituto Clinico Humanitas, Milano (Rozzano) 20089 (Italy)

    2010-08-15

    Purpose: The cylindrical symmetry of vertebrae favors the use of volumetric modulated arc therapy in generating a dose ''hole'' on the center of the vertebrae limiting the dose to the spinal cord. The authors have evaluated if collimator angle is a significant parameter for dose distribution optimization in vertebral metastases. Methods: Three patients with one-three vertebrae involved were considered. Twenty-one differently optimized plans (nine single-arc and 12 double-arc plans) were performed, testing various collimator angle positions. Clinical target volume was defined as the whole vertebrae, excluding the spinal cord canal. The planning target volume (PTV) was defined as CTV+5 mm. Dose prescription was 5x4 Gy{sup 2} with normalization to PTV mean dose. The dose at 1 cm{sup 3} of spinal cord was limited to 11.5Gy. Results: The best plans in terms of target coverage and spinal cord sparing were achieved by two arcs and Arc1-80 deg. and Arc2-280 deg. collimator angles for all the cases considered (i.e., leaf travel parallel to the spinal cord primary orientation). If one arc is used, only 80 deg. reached the objectives. Conclusions: This study demonstrated the role of collimation rotation for the vertebrae metastasis irradiation, with the leaf travel parallel to the spinal cord primary orientation to be better than other solutions. Thus, optimal choice of collimator angle increases the optimization freedom to shape a desired dose distribution.

  15. Real-time fast inverse dose optimization for image guided adaptive radiation therapy-Enhancements to fast inverse dose optimization (FIDO)

    Science.gov (United States)

    Goldman, S. P.; Turnbull, D.; Johnson, C.; Chen, J. Z.; Battista, J. J.

    2009-05-01

    A fast, accurate and stable optimization algorithm is very important for inverse planning of intensity-modulated radiation therapy (IMRT), and for implementing dose-adaptive radiotherapy in the future. Conventional numerical search algorithms with positive beam weight constraints generally require numerous iterations and may produce suboptimal dose results due to trapping in local minima regions of the objective function landscape. A direct solution of the inverse problem using conventional quadratic objective functions without positive beam constraints is more efficient but it will result in unrealistic negative beam weights. We review here a direct solution of the inverse problem that is efficient and does not yield unphysical negative beam weights. In fast inverse dose optimization (FIDO) method the objective function for the optimization of a large number of beamlets is reformulated such that the optimization problem is reducible to a linear set of equations. The optimal set of intensities is then found through a matrix inversion, and negative beamlet intensities are avoided without the need for externally imposed ad hoc conditions. In its original version [S. P. Goldman, J. Z. Chen, and J. J. Battista, in Proceedings of the XIVth International Conference on the Use of Computers in Radiation Therapy, 2004, pp. 112-115; S. P. Goldman, J. Z. Chen, and J. J. Battista, Med. Phys. 32, 3007 (2005)], FIDO was tested on single two-dimensional computed tomography (CT) slices with sharp KERMA beams without scatter, in order to establish a proof of concept which demonstrated that FIDO could be a viable method for the optimization of cancer treatment plans. In this paper we introduce the latest advancements in FIDO that now include not only its application to three-dimensional volumes irradiated by beams with full scatter but include as well a complete implementation of clinical dose-volume constraints including maximum and minimum dose as well as equivalent uniform dose

  16. Assessment of fruit density and leaf number: fruit to optimize crop load of mangosteen

    Directory of Open Access Journals (Sweden)

    Sayan Sdoodee

    2006-09-01

    Full Text Available To optimize crop load of mangosteen, fruit density and leaf number: fruit were assessed using a framework of quadrat cube (0.5 x 0.5 x 0.5 m in 2 consecutive years (2004-2005. Twenty-four 14-year-old uniform trees, field grown at Songkhla province, were selected to arrange 4 levels of crop loads: 1 Extremely low crop load (T1 = 264±5 fruit pt-1, 2 Low crop load (T2 = 826±36 fruit pt-1, 3 Medium crop load (T3 = 1190±27 fruit pt-1 and 4 High crop load (T4 = 1719±36 fruit pt-1. By placing the quadrat cube on the tree canopy, leaves quadrat-1 and fruits quadrat-1 were counted. Relationship between fruits quadrat-1 and fruit number pt-1 was found, and leaf number: fruit was also related to fruit yield pt-1. These results indicate that the assessment of fruit density and leaf number: fruit is of benefit for crop load management. Thus, 9 fruits quadrat-1 and 18 leaves: fruit are recommended to optimize crop load of mangosteen.

  17. Design And Modeling An Automated Digsilent Power System For Optimal New Load Locations

    Directory of Open Access Journals (Sweden)

    Mohamed Saad

    2015-08-01

    Full Text Available Abstract The electric power utilities seek to take advantage of novel approaches to meet growing energy demand. Utilities are under pressure to evolve their classical topologies to increase the usage of distributed generation. Currently the electrical power engineers in many regions of the world are implementing manual methods to measure power consumption for farther assessment of voltage violation. Such process proved to be time consuming costly and inaccurate. Also demand response is a grid management technique where retail or wholesale customers are requested either electronically or manually to reduce their load. Therefore this paper aims to design and model an automated power system for optimal new load locations using DPL DIgSILENT Programming Language. This study is a diagnostic approach that assists system operator about any voltage violation cases that would happen during adding new load to the grid. The process of identifying the optimal bus bar location involves a complicated calculation of the power consumptions at each load bus As a result the DPL program would consider all the IEEE 30 bus internal networks data then a load flow simulation will be executed. To add the new load to the first bus in the network. Therefore the developed model will simulate the new load at each available bus bar in the network and generate three analytical reports for each case that captures the overunder voltage and the loading elements among the grid.

  18. Optimization of nifedipine loaded gastroretentive microcapsules for biliary colic

    Directory of Open Access Journals (Sweden)

    Shaheen Sultana

    2012-01-01

    Full Text Available The aim of this research work was to formulate and systematically evaluate in vitro performance of gastroretentive microcapsules of nifedipine for biliary colic. Cross-linked reinforced alginate-chitosan microcapsules were prepared by ionotropic gelation method using calcium chloride (CaCl 2 as a cross-linking agent. The microcapsules were evaluated for physical characteristics such as particle size, particle shape and surface morphology by scanning electron microscopy, drug entrapment efficiency, in vitro drug release and in vitro bioadhesion studies. Results of preliminary trials indicated that the polymer concentration, cross-linking agent and chitosan had a noticeable effect on size and surface morphology. A Box-Behnken design was employed to study the effect of independent variables, polymer concentration (X1, CaCl 2 concentration (X 2, chitosan (X3 and pH of encapsulation medium (X4 on dependent variables, drug entrapment efficiency and percentage drug release respectively. The entrapment efficiency varied from 6.14 to 79.21% depending upon the independent variables. The release can be sustained for more than 7 hours for all batches. It was observed that polymer and cross-linker concentration had a more significant effect on the dependent variables.Validation of optimization study, performed using 6 confirmatory runs, indicated very high degree of prognostic ability of response surface methodology, with mean percentage error (± SD as -0.85 ± 4.39% and 2.83 ± 2.91% for drug entrapment and drug release. Optimization was done on the basis of maximum entrapment (82.26% which was predicted using 6% alginate, 8.11% CaCl 2, 2% chitosan at a pH of 3.55 of encapsulation medium. The optimized formulation depicted a release of 57.17% at 7 hours. Point prediction tool of design expert software shows 101.91% and 96.82% validity of the predicted model for drug entrapment and percent drug release. The release follow Higuchi kinetics followed by non

  19. Using Maximal Isometric Force to Determine the Optimal Load for Measuring Dynamic Muscle Power

    Science.gov (United States)

    Spiering, Barry A.; Lee, Stuart M. C.; Mulavara, Ajitkumar P.; Bentley, Jason R.; Nash, Roxanne E.; Sinka, Joseph; Bloomberg, Jacob J.

    2009-01-01

    Maximal power output occurs when subjects perform ballistic exercises using loads of 30-50% of one-repetition maximum (1-RM). However, performing 1-RM testing prior to power measurement requires considerable time, especially when testing involves multiple exercises. Maximal isometric force (MIF), which requires substantially less time to measure than 1-RM, might be an acceptable alternative for determining the optimal load for power testing. PURPOSE: To determine the optimal load based on MIF for maximizing dynamic power output during leg press and bench press exercises. METHODS: Twenty healthy volunteers (12 men and 8 women; mean +/- SD age: 31+/-6 y; body mass: 72 +/- 15 kg) performed isometric leg press and bench press movements, during which MIF was measured using force plates. Subsequently, subjects performed ballistic leg press and bench press exercises using loads corresponding to 20%, 30%, 40%, 50%, and 60% of MIF presented in randomized order. Maximal instantaneous power was calculated during the ballistic exercise tests using force plates and position transducers. Repeated-measures ANOVA and Fisher LSD post hoc tests were used to determine the load(s) that elicited maximal power output. RESULTS: For the leg press power test, six subjects were unable to be tested at 20% and 30% MIF because these loads were less than the lightest possible load (i.e., the weight of the unloaded leg press sled assembly [31.4 kg]). For the bench press power test, five subjects were unable to be tested at 20% MIF because these loads were less than the weight of the unloaded aluminum bar (i.e., 11.4 kg). Therefore, these loads were excluded from analysis. A trend (p = 0.07) for a main effect of load existed for the leg press exercise, indicating that the 40% MIF load tended to elicit greater power output than the 60% MIF load (effect size = 0.38). A significant (p . 0.05) main effect of load existed for the bench press exercise; post hoc analysis indicated that the effect of

  20. Cerebral vascular effects of loading dose of dexmedetomidine: A Transcranial Color Doppler study

    Directory of Open Access Journals (Sweden)

    Appavoo Arulvelan

    2016-01-01

    Full Text Available Background: Dexmedetomidine has been widely used in critical care settings because of its property of maintaining stable hemodynamics and inducing conscious sedation. The use of dexmedetomidine is in increasing trend particularly in patients with neurological disorders. Very few studies have focused on the cerebral hemodynamic effects of dexmedetomidine. This study is aimed to address this issue. Methods: Thirty patients without any intracranial pathology were included in this study. Middle cerebral artery flow velocity obtained from transcranial color Doppler was used to assess the cerebral hemodynamic indices. Mean flow velocity (mFV, pulsatility index (PI, cerebral vascular resistant index (CVRi, estimated cerebral perfusion pressure (eCPP, and zero flow pressure (ZFP were calculated bilaterally at baseline and after infusion of injection Dexmedetomidine 1 mcg/Kg over 10 min. Results: Twenty-six patients completed the study protocol. After administration of loading dose of dexmedetomidine, mFV and eCPP values were significantly decreased in both hemispheres (P < 0.05; PI, CVRi, and ZFP values showed significant increase (P < 0.05 after dexmedetomidine infusion. Conclusion: Increase in PI, CVRi, and ZFP suggests that there is a possibility of an increase in distal cerebral vascular resistance (CVR with loading dose of dexmedetomidine. Decrease in mFV and eCPP along with an increase in CVR may lead to a decrease in cerebral perfusion. This effect can be exaggerated in patients with preexisting neurological illness. Further studies are needed to evaluate the effect of dexmedetomidine on various other pathological conditions involving brain like traumatic brain injury and vascular malformations.

  1. Optimized scalar promotion with load and splat SIMD instructions

    Science.gov (United States)

    Eichenberger, Alexander E; Gschwind, Michael K; Gunnels, John A

    2013-10-29

    Mechanisms for optimizing scalar code executed on a single instruction multiple data (SIMD) engine are provided. Placement of vector operation-splat operations may be determined based on an identification of scalar and SIMD operations in an original code representation. The original code representation may be modified to insert the vector operation-splat operations based on the determined placement of vector operation-splat operations to generate a first modified code representation. Placement of separate splat operations may be determined based on identification of scalar and SIMD operations in the first modified code representation. The first modified code representation may be modified to insert or delete separate splat operations based on the determined placement of the separate splat operations to generate a second modified code representation. SIMD code may be output based on the second modified code representation for execution by the SIMD engine.

  2. Optimal Dosing for Targeted Therapies in Oncology: Drug Development Cases Leading by Example.

    Science.gov (United States)

    Sachs, Jeffrey R; Mayawala, Kapil; Gadamsetty, Satvik; Kang, Soonmo Peter; de Alwis, Dinesh P

    2016-03-15

    One of the key objectives of oncology first-in-human trials has often been to establish the maximum tolerated dose (MTD). However, targeted therapies might not exhibit dose-limiting toxicities (DLT) at doses significantly higher than sufficiently active doses, and there is frequently a limited ability to objectively quantify adverse events. Thus, while MTD-based determination of recommended phase II dose may have yielded appropriate dosing for some cytotoxics, targeted therapeutics (including monoclonal antibodies and/or immunotherapies) sometimes need alternative or complementary strategies to help identify dose ranges for a randomized dose-ranging study. One complementary strategy is to define a biologically efficacious dose (BED) using an "effect marker." An effect marker could be a target engagement, pharmacodynamic, or disease progression marker (change in tumor size for solid tumors or bone marrow blast count for some hematologic tumors). Although the concept of BED has been discussed extensively, we review specific examples in which the approach influenced oncology clinical development. Data extracted from the literature and the examples support improving dose selection strategies to benefit patients, providers, and the biopharmaceutical industry. Although the examples illustrate key contributions of effect markers in dose selection, no one-size-fits-all approach to dosing can be justified. Higher-than-optimal dosing can increase toxicity in later trials (and in clinical use), which can have a negative impact on efficacy (via lower adherence or direct sequelae of toxicities). Proper dose selection in oncology should follow a multifactorial decision process leading to a randomized, dose-ranging study instead of a single phase II dose. ©2015 American Association for Cancer Research.

  3. Least Squares-support Vector Machine Load Forecasting Approach Optimized by Bacterial Colony Chemotaxis Method

    Institute of Scientific and Technical Information of China (English)

    ZENG Ming; LU Chunquan; TIAN Kuo; XUE Song

    2011-01-01

    During the Twelfth Five-Year plan, large-scale construction of smart grid with safe and stable operation requires a timely and accurate short-term load forecasting method. Moreover, along with the full-scale smart grid construction, the power supply mode and consumption mode of the whole system can be optimized through the accurate short-term load forecasting; and the security, stability and cleanness of the system can be guaranteed.

  4. Polyurethane foam loaded with sodium dodecylsulfate for the extraction of 'quat' pesticides from aqueous medium: Optimization of loading conditions.

    Science.gov (United States)

    Vinhal, Jonas O; Lima, Claudio F; Cassella, Ricardo J

    2016-09-01

    The cationic herbicides paraquat, diquat and difenzoquat are largely used in different cultures worldwide. With this, there is an intrinsic risk of environmental contamination when these herbicides achieve natural waters. The goal of this work was to propose a novel and low-cost sorbent for the removal of the cited herbicides from aqueous medium. The proposed sorbent was prepared by loading polyurethane foam with sodium dodecylsulfate. The influence of several parameters (SDS concentration, HCl concentration and shaking time) on the loading process was investigated. The results obtained in this work demonstrated that all studied variables influenced the loading process, having significant effect on the extraction efficiency of the resulted PUF-SDS. At optimized conditions, the PUF was loaded by shaking 200mg of crushed foam with 200mL of a solution containing 5.0×10(-3)molL(-1) SDS and 0.25molL(-1) HCl, for 30min. The obtained PUF-SDS was efficient for removing the three herbicides from aqueous medium, achieving extraction percentages higher than 90%. The sorption process followed a pseudo second-order kinetics, which presented excellent predictive capacity of the amount of herbicide retained with time.

  5. Digital radiography of scoliosis with a scanning method: radiation dose optimization

    Energy Technology Data Exchange (ETDEWEB)

    Geijer, Haakan; Andersson, Torbjoern [Department of Radiology, Oerebro University Hospital, 701 85 Oerebro (Sweden); Verdonck, Bert [Philips Medical Systems, P.O. Box 10,000, 5680 Best (Netherlands); Beckman, Karl-Wilhelm; Persliden, Jan [Department of Medical Physics, Oerebro University Hospital, 701 85 Oerebro (Sweden)

    2003-03-01

    The aim of this study was optimization of the radiation dose-image quality relationship for a digital scanning method of scoliosis radiography. The examination is performed as a digital multi-image translation scan that is reconstructed to a single image in a workstation. Entrance dose was recorded with thermoluminescent dosimeters placed dorsally on an Alderson phantom. At the same time, kerma area product (KAP) values were recorded. A Monte Carlo calculation of effective dose was also made. Image quality was evaluated with a contrast-detail phantom and Visual Grading. The radiation dose was reduced by lowering the image intensifier entrance dose request, adjusting pulse frequency and scan speed, and by raising tube voltage. The calculated effective dose was reduced from 0.15 to 0.05 mSv with reduction of KAP from 1.07 to 0.25 Gy cm{sup 2} and entrance dose from 0.90 to 0.21 mGy. The image quality was reduced with the Image Quality Figure going from 52 to 62 and a corresponding reduction in image quality as assessed with Visual Grading. The optimization resulted in a dose reduction to 31% of the original effective dose with an acceptable reduction in image quality considering the intended use of the images for angle measurements. (orig.)

  6. Exploiting Additive Manufacturing Infill in Topology Optimization for Improved Buckling Load

    Directory of Open Access Journals (Sweden)

    Anders Clausen

    2016-06-01

    Full Text Available Additive manufacturing (AM permits the fabrication of functionally optimized components with high geometrical complexity. The opportunity of using porous infill as an integrated part of the manufacturing process is an example of a unique AM feature. Automated design methods are still incapable of fully exploiting this design freedom. In this work, we show how the so-called coating approach to topology optimization provides a means for designing infill-based components that possess a strongly improved buckling load and, as a result, improved structural stability. The suggested approach thereby addresses an important inadequacy of the standard minimum compliance topology optimization approach, in which buckling is rarely accounted for; rather, a satisfactory buckling load is usually assured through a post-processing step that may lead to sub-optimal components. The present work compares the standard and coating approaches to topology optimization for the MBB beam benchmark case. The optimized structures are additively manufactured using a filamentary technique. This experimental study validates the numerical model used in the coating approach. Depending on the properties of the infill material, the buckling load may be more than four times higher than that of solid structures optimized under the same conditions.

  7. Simultaneous optimization of dose distributions and fractionation schemes in particle radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Unkelbach, Jan; Zeng, Chuan [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114 (United States); Engelsman, Martijn [Faculty of Applied Physics, Delft University of Technology/HollandPTC, 2628 CJ Delft (Netherlands)

    2013-09-15

    Purpose: The paper considers the fractionation problem in intensity modulated proton therapy (IMPT). Conventionally, IMPT fields are optimized independently of the fractionation scheme. In this work, we discuss the simultaneous optimization of fractionation scheme and pencil beam intensities.Methods: This is performed by allowing for distinct pencil beam intensities in each fraction, which are optimized using objective and constraint functions based on biologically equivalent dose (BED). The paper presents a model that mimics an IMPT treatment with a single incident beam direction for which the optimal fractionation scheme can be determined despite the nonconvexity of the BED-based treatment planning problem.Results: For this model, it is shown that a small α/β ratio in the tumor gives rise to a hypofractionated treatment, whereas a large α/β ratio gives rise to hyperfractionation. It is further demonstrated that, for intermediate α/β ratios in the tumor, a nonuniform fractionation scheme emerges, in which it is optimal to deliver different dose distributions in subsequent fractions. The intuitive explanation for this phenomenon is as follows: By varying the dose distribution in the tumor between fractions, the same total BED can be achieved with a lower physical dose. If it is possible to achieve this dose variation in the tumor without varying the dose in the normal tissue (which would have an adverse effect), the reduction in physical dose may lead to a net reduction of the normal tissue BED. For proton therapy, this is indeed possible to some degree because the entrance dose is mostly independent of the range of the proton pencil beam.Conclusions: The paper provides conceptual insight into the interdependence of optimal fractionation schemes and the spatial optimization of dose distributions. It demonstrates the emergence of nonuniform fractionation schemes that arise from the standard BED model when IMPT fields and fractionation scheme are optimized

  8. SN-38 loading capacity of hydrophobic polymer blend nanoparticles: formulation, optimization and efficacy evaluation.

    Science.gov (United States)

    Dimchevska, Simona; Geskovski, Nikola; Petruševski, Gjorgji; Chacorovska, Marina; Popeski-Dimovski, Riste; Ugarkovic, Sonja; Goracinova, Katerina

    2017-03-01

    One of the most important problems in nanoencapsulation of extremely hydrophobic drugs is poor drug loading due to rapid drug crystallization outside the polymer core. The effort to use nanoprecipitation, as a simple one-step procedure with good reproducibility and FDA approved polymers like Poly(lactic-co-glycolic acid) (PLGA) and Polycaprolactone (PCL), will only potentiate this issue. Considering that drug loading is one of the key defining characteristics, in this study we attempted to examine whether the nanoparticle (NP) core composed of two hydrophobic polymers will provide increased drug loading for 7-Ethyl-10-hydroxy-camptothecin (SN-38), relative to NPs prepared using individual polymers. D-optimal design was applied to optimize PLGA/PCL ratio in the polymer blend and the mode of addition of the amphiphilic copolymer Lutrol(®)F127 in order to maximize SN-38 loading and obtain NPs with acceptable size for passive tumor targeting. Drug/polymer and polymer/polymer interaction analysis pointed to high degree of compatibility and miscibility among both hydrophobic polymers, providing core configuration with higher drug loading capacity. Toxicity studies outlined the biocompatibility of the blank NPs. Increased in vitro efficacy of drug-loaded NPs compared to the free drug was confirmed by growth inhibition studies using SW-480 cell line. Additionally, the optimized NP formulation showed very promising blood circulation profile with elimination half-time of 7.4 h.

  9. Inertia Matching Manipulability and Load Matching Optimization for Humanoid Jumping Robot

    Directory of Open Access Journals (Sweden)

    Zhaohong Xu

    2008-11-01

    Full Text Available Human jumping motion includes stance phase, flight phase and landing impact phase. Jumping robot belongs to a variable constraints system because every phase has different constraint conditions. An unified dynamics equation during stance phase and flight phase is established based on floated-basis space. Inertia matching is used to analyze actuator/gear systems and select the optimum gear ratio based on the transmission performance between the torque produced at the actuator and the torque applied to the load. Load matching is an important index which affects jumping performance and reflects the capability of supporting a weight or mass. It also affects the distributing of the center of gravity (COG. Regarding jumping robot as a redundant manipulator with a load at end-effector, inertia matching can be applied to optimize load matching for jumping robot. Inertia matching manipulability and directional manipulability are easy to analyze and optimize the load matching parameters. A 5th order polynomial function is defined to plan COG trajectory of jumping motion, taking into account the constraint conditions of both velocity and acceleration. Finally, the numerical simulation of vertical jumping and experimental results show inertia matching is in direct proportion to jumping height, and inertia matching manipulability is a valid method to load matching optimization and conceptual design of robot.

  10. Comparison of initial loading doses of 5 mg and 10 mg for warfarin therapy

    Directory of Open Access Journals (Sweden)

    Sidnei Lastória

    2014-03-01

    Full Text Available CONTEXT: The question of what is the best loading dosage of warfarin when starting anticoagulant treatment has been under discussion for ten years. We were unable to find any comparative studies of these characteristics conducted here in Brazil. OBJECTIVE: To compare the safety and efficacy of two initial warfarin dosage regimens for anticoagulant treatment. METHODS: One-hundred and ten consecutive patients of both sexes, with indications for anticoagulation because of venous or arterial thromboembolism, were analyzed prospectively. During the first 3 days of treatment, these patients were given adequate heparin to keep aPTT (activated partial thromboplastin time between 1.5 and 2.5, plus 5 mg of warfarin. From the fourth day onwards, their warfarin doses were adjusted using International Normalized Ratios (INR; target range: 2 to 3. This prospective cohort was compared with a historical series of 110 patients had been given 10 mg of warfarin on the first 2 days and 5 mg on the third day with adjustments based on INR thereafter. Outcomes analyzed were as follows: recurrence of thromboembolism, bleeding events and time taken to enter the therapeutic range. RESULTS: Efficacy, safety and length of hospital stay were similar in both samples. The sample that were given 10 mg entered the therapeutic range earlier (means: 4.5 days vs. 5.8 days, were on lower doses at discharge and had better therapeutic indicators at the first return appointment. CONCLUSIONS: The 10 mg dosage regimen took less time to attain the therapeutic range and was associated with lower warfarin doses at discharge and better INR at first out-patients follow-up visit.

  11. Impacts of the Load Models on Optimal Planning of Distributed Generation in Distribution System

    Directory of Open Access Journals (Sweden)

    Aashish Kumar Bohre

    2015-01-01

    Full Text Available The optimal planning (sizing and siting of the distributed generations (DGs by using butterfly-PSO/BF-PSO technique to investigate the impacts of load models is presented in this work. The validity of the evaluated results is confirmed by comparing with well-known Genetic Algorithm (GA and standard or conventional particle swarm optimization (PSO. To exhibit its compatibility in terms of load management, an impact of different load models on the size and location of DG has also been presented in this work. The fitness evolution function explored is the multiobjective function (FMO, which is based on the three significant indexes such as active power loss, reactive power loss, and voltage deviation index. The optimal solution is obtained by minimizing the multiobjective fitness function using BF-PSO, GA, and PSO technique. The comparison of the different optimization techniques is given for the different types of load models such as constant, industrial, residential, and commercial load models. The results clearly show that the BF-PSO technique presents the superior solution in terms of compatibility as well as computation time and efforts both. The algorithm has been carried out with 15-bus radial and 30-bus mesh system.

  12. Digital radiography: optimization of image quality and dose using multi-frequency software

    Energy Technology Data Exchange (ETDEWEB)

    Precht, H. [University College Lillebelt, Conrad Research Center, Odense (Denmark); Gerke, O. [Odense University Hospital, Department of Nuclear Medicine, Odense (Denmark); University of Southern Denmark, Research Unit of Health Economics, Odense (Denmark); Rosendahl, K. [Haukeland University Hospital, Section of Pediatric Radiology, Bergen (Norway); University of Bergen, Institute of Surgical Sciences, Bergen (Norway); Tingberg, A. [Skaane University Hospital, Lund University (Sweden); Medical Radiation Physics, Department of Clinical Sciences, Malmoe (Sweden); Waaler, D. [Gjoevik University College, Gjoevik (Norway)

    2012-09-15

    New developments in processing of digital radiographs (DR), including multi-frequency processing (MFP), allow optimization of image quality and radiation dose. This is particularly promising in children as they are believed to be more sensitive to ionizing radiation than adults. To examine whether the use of MFP software reduces the radiation dose without compromising quality at DR of the femur in 5-year-old-equivalent anthropomorphic and technical phantoms. A total of 110 images of an anthropomorphic phantom were imaged on a DR system (Canon DR with CXDI-50 C detector and MLT[S] software) and analyzed by three pediatric radiologists using Visual Grading Analysis. In addition, 3,500 images taken of a technical contrast-detail phantom (CDRAD 2.0) provide an objective image-quality assessment. Optimal image-quality was maintained at a dose reduction of 61% with MLT(S) optimized images. Even for images of diagnostic quality, MLT(S) provided a dose reduction of 88% as compared to the reference image. Software impact on image quality was found significant for dose (mAs), dynamic range dark region and frequency band. By optimizing image processing parameters, a significant dose reduction is possible without significant loss of image quality. (orig.)

  13. MO-PIS-Exhibit Hall-01: Imaging: CT Dose Optimization Technologies I

    Energy Technology Data Exchange (ETDEWEB)

    Denison, K; Smith, S [GE Healthcare, Waukesha, WI (United States)

    2014-06-15

    Partners in Solutions is an exciting new program in which AAPM partners with our vendors to present practical “hands-on” information about the equipment and software systems that we use in our clinics. The imaging topic this year is CT scanner dose optimization capabilities. Note that the sessions are being held in a special purpose room built on the Exhibit Hall Floor, to encourage further interaction with the vendors. Dose Optimization Capabilities of GE Computed Tomography Scanners Presentation Time: 11:15 – 11:45 AM GE Healthcare is dedicated to the delivery of high quality clinical images through the development of technologies, which optimize the application of ionizing radiation. In computed tomography, dose management solutions fall into four categories: employs projection data and statistical modeling to decrease noise in the reconstructed image - creating an opportunity for mA reduction in the acquisition of diagnostic images. Veo represents true Model Based Iterative Reconstruction (MBiR). Using high-level algorithms in tandem with advanced computing power, Veo enables lower pixel noise standard deviation and improved spatial resolution within a single image. Advanced Adaptive Image Filters allow for maintenance of spatial resolution while reducing image noise. Examples of adaptive image space filters include Neuro 3-D filters and Cardiac Noise Reduction Filters. AutomA adjusts mA along the z-axis and is the CT equivalent of auto exposure control in conventional x-ray systems. Dynamic Z-axis Tracking offers an additional opportunity for dose reduction in helical acquisitions while SmartTrack Z-axis Tracking serves to ensure beam, collimator and detector alignment during tube rotation. SmartmA provides angular mA modulation. ECG Helical Modulation reduces mA during the systolic phase of the heart cycle. SmartBeam optimization uses bowtie beam-shaping hardware and software to filter off-axis x-rays - minimizing dose and reducing x-ray scatter. The

  14. Three-Dimensional Dose Optimization for Noncoplanar Treatment Planning with Conformal Fields.

    Science.gov (United States)

    Ma, Ying-Chang L.

    1990-01-01

    Recent advances in imaging techniques, especially three dimensional reconstruction of CT images, have made precision tumor localization feasible. These imaging techniques along with developments in computer controlled radiation treatment machines have provided an important thrust in developing better techniques for cancer treatment. This often requires a complex noncoplanar beam arrangements and elaborate treatment planning, which, unfortunately, are time consuming, costly and dependent on operator expertise and experience. A reliable operator-independent dose optimization tool is therefore desirable, especially for 3D treatment planning. In this dissertation, several approaches (linear programming, quadratic programming, and direct search methods) of computer optimization using various criteria including least sire fitting on the 90% isodose to target periphery, dose uniformity, and integral dose are presented. All of these methods are subject to restrictions on the upper limit of the dose to critical organs. In the quadratic programming approach, Kuhn-Tucker theory was employed to convert the quadratic problem into one which permits application of the very powerful, revised simplex method. Several examples are used to analyze the effectiveness of these dose optimization approaches. The studies show that the quadratic programming approach with the criteria of least square fitting and critical organ constraints is superior in efficiency for dose optimization in 3D treatment planning, particularly for cases with a large number of beams. Use of least square fitting allows one to deduce optimized plans for irregularly shaped targets by employing a multi-isocentric technique. Our studies also illustrate the advantages of using irregular conformal fields, optimized beam energy, and noncoplanar beam arrangements in contrast to the conventional treatment which uses a symmetrical rectangular collimator, fixed beam energy, and coplanar beam arrangements. Optimized plans can

  15. Optimal Switchable Load Sizing and Scheduling for Standalone Renewable Energy Systems

    OpenAIRE

    Habib, Abdulelah H.; Disfani, Vahid R.; Kleissl, Jan; de Callafon, Raymond A.

    2017-01-01

    The variability of solar energy in off-grid systems dictates the sizing of energy storage systems along with the sizing and scheduling of loads present in the off-grid system. Unfortunately, energy storage may be costly, while frequent switching of loads in the absence of an energy storage system causes wear and tear and should be avoided. Yet, the amount of solar energy utilized should be maximized and the problem of finding the optimal static load size of a finite number of discrete electri...

  16. Optimal Cooling Load Sharing Strategies for Different Types of Absorption Chillers in Trigeneration Plants

    Directory of Open Access Journals (Sweden)

    Benedetto Conte

    2016-07-01

    Full Text Available Trigeneration plants can use different types of chillers in the same plant, typically single effect and double effect absorption chillers, vapour compression chillers and also cooling storage systems. The highly variable cooling demand of the buildings connected to a district heating and cooling (DHC network has to be distributed among these chillers to achieve lower operating costs and higher energy efficiencies. This problem is difficult to solve due to the different partial load behaviour of each chiller and the different chiller combinations that can cover a certain cooling demand using an appropriate sizing of the cooling storage. The objective of this paper is to optimize the daily plant operation of an existing trigeneration plant based on cogeneration engines and to study the optimal cooling load sharing between different types of absorption chillers using a mixed integer linear programming (MILP model. Real data from a trigeneration plant connected to a DHC close to Barcelona (Spain is used for the development of this model. The cooling load distribution among the different units is heavily influenced by the price of the electricity sold to the grid which rules the duration of the operation time of the engines. The main parameter to compare load distribution configurations is the primary energy saving indicator. Cooling load distribution among the different chillers changes also with the load of the whole plant because the chiller performance changes with load.

  17. Backscattering measuring system for optimization of intravenous laser irradiation dose

    Science.gov (United States)

    Rusina, Tatyana V.; Popov, V. D.; Melnik, Ivan S.; Dets, Sergiy M.

    1996-11-01

    Intravenous laser blood irradiation as an effective method of biostimulation and physiotherapy becomes a more popular procedure. Optimal irradiation conditions for each patient are needed to be established individually. A fiber optics feedback system combined with conventional intravenous laser irradiation system was developed to control of irradiation process. The system consists of He-Ne laser, fiber optics probe and signal analyzer. Intravenous blood irradiation was performed in 7 healthy volunteers and 19 patients with different diseases. Measurements in vivo were related to in vitro blood irradiation which was performed in the same conditions with force-circulated venous blood. Comparison of temporal variations of backscattered light during all irradiation procedures has shown a strong discrepancy on optical properties of blood in patients with various health disorders since second procedure. The best cure effect was achieved when intensity of backscattered light was constant during at least five minutes. As a result, the optical irradiation does was considered to be equal 20 minutes' exposure of 3 mW He-Ne laser light at the end of fourth procedure.

  18. Energy Optimization And Calculation Of Dose Absorption Enhancement Factor In Photon Activation Therapy

    Directory of Open Access Journals (Sweden)

    Hassan Ranjbar

    2010-06-01

    Full Text Available Introduction: Secondary radiation such as photoelectrons, Auger electrons and characteristic radiations cause a local boost in dose for a tumor when irradiated with an external X-ray beam after being loaded with elements capable of activating the tumor, e.g.; I and Gd. Materials and Methods:  In this investigation, the MCNPX code was used for simulation and calculation of dose enhancement factor for a tumor loaded with activating elements. The designed model comprised the X-ray source, phantom (target tissue and loaded tumor with activating agent, detector, interactions modeling and results. The source was defined as monochromatic and plane surface situated at 50 cm (z = 50. Phantom geometry was a 10 × 10 × 10 cm3 cube centered at (0, 0, 0 with a 2.2 × 2.2 × 2.2 cm3 cubic tumor with a center located at 3 cm depth inside the phantom Results: Dose enhancement factor and optimum energy in radiotherapy are evaluated using the photon activation therapy method. Result show that the dose enhancement factor increases with activating concentration in the tumor. The maximum dose enhancement factor for iodine in the tumor occurs for photons in the energy range of 50-60 keV. Dose uniformity is less for lower energy photons within the activated region inside the tumor. Results indicate that the dose enhancement factor varies linearly with the activating concentration agent. Discussion and Conclusion: In this study, the obtained results point out a considerable enhancement in dose in the presence of activating agents in the tumor regions.

  19. Optimal power flow calculation for power system with UPFC considering load rate equalization

    Science.gov (United States)

    Liu, Jiankun; Chen, Jing; Zhang, Qingsong

    2017-06-01

    Unified power flow controller (UPFC) device can change system electrical quantity (such as voltage, impedance, phase angle, etc.) rapidly and flexibly under the premise of maintain security, stability and reliability of power system, thus can improve the transmission power and transmission line utilization, so as to enhance the power supply capacity of the power grid. Based on a thorough study of the steady-state model of UPFC, taking load rate equalization as objective function, the optimal power flow model is established with UPFC, and simplified interior point method is used to solve it. Finally, optimal power flow of 24 continuous sections actual data is calculated on a typical day of Nanjing network. The results show that the optimal power flow calculation with UPFC can optimize the load rate equalization on the basis of eliminating line overload, improving the voltage level of local power network.

  20. Case study on implementation of the dose constraint concept in optimization in working environment

    Energy Technology Data Exchange (ETDEWEB)

    Krajewska, Grazyna; Krajewski, Pawel [Central Laboratory for Radiological Protection, PL-03194, Warsaw (Poland)

    2014-07-01

    A case study of already fixed dose constrain values in nuclear medicine sector, indicated that, the practical implementation of ICRP principle of optimization ( Publication 103, ICRP, 2007) still hit on methodology problems due to lack of adequate numerous monitoring data of internal contamination and complicated mathematical formalism. In practice, to ensure that 'the likelihood of incurring exposure, the number of people exposed, and the magnitude of their individual doses are kept as low as reasonably achievable', the baseline of effective doses together with statistical distribution is required. Furthermore, as it has revealed in this study, doses PHP's generated with MC methods had un-regularly shapes, depending on random operations rather than routine procedures. The role of dose constraints for occupational exposures, was further elaborated in Publication 101 (ICRP, 2006) as 'the dose constraint is a value of individual dose used to limit the range of options considered in the process of optimization'. The revisions of the International Basic Safety Standards as well as the Euratom Basic Safety Standard Directive both aim to implement new ICRP recommendations and have requirements to use dose constraints, defined broadly along the lines provided by the ICRP, and suggest that values be selected from the bands recommended by the ICRP. These will be obligatory adopted in the national regulations by regulatory authorities of EU countries. However, due to accidental characteristics of monitoring data, the 95% confidence tail of the doses for the most highly exposed individuals is near the limit of 20 mSv per year. This is apparently observed in the particular endocrinology units dealing with I-131 therapy. One might concluded that dose limitation and optimization are viewed as sufficient for the management of occupational exposures and reasonably be achieved. (authors)

  1. Poloxamer 407-based intranasal thermoreversible gel of zolmitriptan-loaded nanoethosomes: formulation, optimization, evaluation and permeation studies.

    Science.gov (United States)

    Shelke, Santosh; Shahi, Sadhana; Jalalpure, Sunil; Dhamecha, Dinesh

    2016-12-01

    Zolmitriptan is the drug of choice for migraine, but low oral bioavailability (<50%) and recurrence of migraine lead to frequent dosing and increase in associated side effects. Increase in the residence time of drug at the site of drug absorption along with direct nose to brain targeting of zolmitriptan can be a solution to the existing problems. Hence, in the present investigation, thermoreversible intranasal gel of zolmitriptan-loaded nanoethosomes was formulated by using mucoadhesive polymers to increase the residence of the drug into the nasal cavity. The preparation of ethosomes was optimized by using 3(2) factorial design for percent drug entrapment efficiency, vesicle size, zeta potential, and polydispersity index. Optimized formulation E6 showed the vesicle size (171.67 nm) and entrapment efficiency (66%) when compared with the other formulations. Thermoreversible gels prepared by using poloxamer 407 showed the phase transition temperature at 32-33 °C which was in line with the nasal physiological temperature. The optimized ethosomes were loaded into the thermoreversible mucoadhesive gel optimized by varying concentrations of poloxamer 407, carbopol 934, HPMC K100, and evaluated for gel strength, gelation temperature, mucoadhesive strength, in vitro drug release, and ex vivo drug permeation, where G3 and G6 were found to be optimized formulations. In vitro drug release was studied by different kinetic models suggested that G3 (n = 0.582) and G6 (n = 0.648) showed Korsemeyer-Peppas (KKP) model indicating non-Fickian release profiles. A permeation coefficient of 5.92 and 5.9 µg/cm(2) for G3 and G6, respectively, revealed very little difference in release rate after 24 h between both the formulations. Non-toxic nature of the gels on columnar epithelial cells was confirmed by histopathological evaluation.

  2. Optimized Load Shedding Approach for Grid-Connected DC Microgrid Systems under Realistic Constraints

    Directory of Open Access Journals (Sweden)

    Leonardo Trigueiro dos Santos

    2016-12-01

    Full Text Available The microgrid system is an answer to the necessity of increasing renewable energy penetration and also works as a bridge for the future smart grid. Considering the microgrid system applied to commercial building equipped with photovoltaic sources, the usage of a DC microgrid architecture can improve the efficiency of the system, while ensuring robustness and reducing the overall energy cost. Given the power grid stress and the intermittency of the DC microgrid power production, backup power provision and load shedding operations may occur to stabilize the DC bus voltage. Based on the knapsack problem formulation, this paper presents a realistic optimization approach to shedding a building’s appliances, considering the priority of each appliance, and also considering a minimum amount of load that must be attended. The problem is solved by mixed integer linear programming and the CPLEX solver. The proposed architecture ensures critical load supply and voltage stabilization through the real-time operation of the operational algorithm allowing the load shedding optimization approach to be applied without compromising the robustness of the system. The results obtained by simulation prove that the DC microgrid is able to supply the building power network by applying the load shedding optimization program to overcome, mainly, the renewable energy intermittency.

  3. Development and Optimization of a Novel Prolonged Release Formulation to Resist Alcohol-Induced Dose Dumping.

    Science.gov (United States)

    Gujjar, Chaitanya Yogananda; Rallabandi, Balaramesha Chary; Gannu, Ramesh; Deulkar, Vallabh Subashrao

    2016-04-01

    Alcohol-induced dose dumping is a serious concern for the orally administered prolonged release dosage forms. The study was designed to optimize the independent variables, propylene glycol alginate (PGA), Eudragit RS PO (ERS) and coating in mucoadhesive quetiapine prolonged release tablets 200 mg required for preventing the alcohol-induced dose dumping. Optimal design based on response surface methodology was employed for the optimization of the composition. The formulations are evaluated for in vitro drug release in hydrochloric acid alone and with 40% v/v ethanol. The responses, dissolution at 120 min without alcohol (R1) and dissolution at 120 min with alcohol (R2), were statistically evaluated and regression equations are generated. PGA as a hydrophilic polymeric matrix was dumping the dose when dissolutions are carried in 0.1 N hydrochloric acid containing 40% v/v ethanol. ERS addition was giving structural support to the swelling and gelling property of PGA, and thus, was reducing the PGA erosion in dissolution media containing ethanol. Among the formulations, four formulations with diverse composition were meeting the target dissolution (30-40%) in both the conditions. The statistical validity of the mathematical equations was established, and the optimum concentration of the factors was established. Validation of the study with six confirmatory runs indicated high degree of prognostic ability of response surface methodology. Further coating with ReadiLycoat was providing an additional resistance to the alcohol-induced dose dumping. Optimized compositions showed resistance to dose dumping in the presence of alcohol.

  4. Optimal vaccine schedules to maintain measles elimination with a two-dose routine policy.

    Science.gov (United States)

    McKEE, A; Shea, K; Ferrari, M J

    2017-01-01

    Measles was eliminated in the Americas in 2002 by a combination of routine immunizations and supplementary immunization activities. Recent outbreaks underscore the importance of reconsidering vaccine policy in order to maintain elimination. We constructed an age-structured dynamical model for the distribution of immunity in a population with routine immunization and without disease, and analysed the steady state for an idealized age structure and for real age structures of countries in the Americas. We compared the level of immunity maintained by current policy in these countries to the level maintainable by an optimal policy. The optimal age target for the first routine dose of measles vaccine depends on the timing and coverage of both doses. Similarly, the optimal age target for the second dose of measles vaccine depends on the timing and coverage of the first dose. The age targets for the first and second doses of measles vaccine should be adjusted for the post-elimination era, by specifically accounting for current context, including realized coverage of both doses, and altered maternal immunity. Doing so can greatly improve the proportion immune within a population, and therefore the chances of maintaining measles elimination, without changing coverage.

  5. Statistical design for formulation optimization of hydrocortisone butyrate-loaded PLGA nanoparticles.

    Science.gov (United States)

    Yang, Xiaoyan; Patel, Sulabh; Sheng, Ye; Pal, Dhananjay; Mitra, Ashim K

    2014-06-01

    The aim of this investigation was to develop hydrocortisone butyrate (HB)-loaded poly(D,L-lactic-co-glycolic acid) (PLGA) nanoparticles (NP) with ideal encapsulation efficiency (EE), particle size, and drug loading (DL) under emulsion solvent evaporation technique utilizing various experimental statistical design modules. Experimental designs were used to investigate specific effects of independent variables during preparation of HB-loaded PLGA NP and corresponding responses in optimizing the formulation. Plackett-Burman design for independent variables was first conducted to prescreen various formulation and process variables during the development of NP. Selected primary variables were further optimized by central composite design. This process leads to an optimum formulation with desired EE, particle size, and DL. Contour plots and response surface curves display visual diagrammatic relationships between the experimental responses and input variables. The concentration of PLGA, drug, and polyvinyl alcohol and sonication time were the critical factors influencing the responses analyzed. Optimized formulation showed EE of 90.6%, particle size of 164.3 nm, and DL of 64.35%. This study demonstrates that statistical experimental design methodology can optimize the formulation and process variables to achieve favorable responses for HB-loaded NP.

  6. Optimization of piezoelectric bimorph actuators with active damping for static and dynamic loads

    DEFF Research Database (Denmark)

    Donoso, Alberto; Sigmund, Ole

    2009-01-01

    The paper considers optimal design problems in the context of active damping. More specifically, we are interested in controlling the tip-deflection of a cantilever beam subjected to static and time-harmonic loading on its free extreme. First, the thickness profile of a piezoelectric bimorph...

  7. Towards Cost and Comfort Based Hybrid Optimization for Residential Load Scheduling in a Smart Grid

    Directory of Open Access Journals (Sweden)

    Nadeem Javaid

    2017-10-01

    Full Text Available In a smart grid, several optimization techniques have been developed to schedule load in the residential area. Most of these techniques aim at minimizing the energy consumption cost and the comfort of electricity consumer. Conversely, maintaining a balance between two conflicting objectives: energy consumption cost and user comfort is still a challenging task. Therefore, in this paper, we aim to minimize the electricity cost and user discomfort while taking into account the peak energy consumption. In this regard, we implement and analyse the performance of a traditional dynamic programming (DP technique and two heuristic optimization techniques: genetic algorithm (GA and binary particle swarm optimization (BPSO for residential load management. Based on these techniques, we propose a hybrid scheme named GAPSO for residential load scheduling, so as to optimize the desired objective function. In order to alleviate the complexity of the problem, the multi dimensional knapsack is used to ensure that the load of electricity consumer will not escalate during peak hours. The proposed model is evaluated based on two pricing schemes: day-ahead and critical peak pricing for single and multiple days. Furthermore, feasible regions are calculated and analysed to develop a relationship between power consumption, electricity cost, and user discomfort. The simulation results are compared with GA, BPSO and DP, and validate that the proposed hybrid scheme reflects substantial savings in electricity bills with minimum user discomfort. Moreover, results also show a phenomenal reduction in peak power consumption.

  8. The dependence of optimal fractionation schemes on the spatial dose distribution

    Science.gov (United States)

    Unkelbach, Jan; Craft, David; Salari, Ehsan; Ramakrishnan, Jagdish; Bortfeld, Thomas

    2013-01-01

    We consider the fractionation problem in radiation therapy. Tumor sites in which the dose-limiting organ at risk (OAR) receives a substantially lower dose than the tumor, bear potential for hypofractionation even if the α/β-ratio of the tumor is larger than the α/β-ratio of the OAR. In this work, we analyze the interdependence of the optimal fractionation scheme and the spatial dose distribution in the OAR. In particular, we derive a criterion under which a hypofractionation regimen is indicated for both a parallel and a serial OAR. The approach is based on the concept of the biologically effective dose (BED). For a hypothetical homogeneously irradiated OAR, it has been shown that hypofractionation is suggested by the BED model if the α/β-ratio of the OAR is larger than α/β-ratio of the tumor times the sparing factor, i.e. the ratio of the dose received by the tumor and the OAR. In this work, we generalize this result to inhomogeneous dose distributions in the OAR. For a parallel OAR, we determine the optimal fractionation scheme by minimizing the integral BED in the OAR for a fixed BED in the tumor. For a serial structure, we minimize the maximum BED in the OAR. This leads to analytical expressions for an effective sparing factor for the OAR, which provides a criterion for hypofractionation. The implications of the model are discussed for lung tumor treatments. It is shown that the model supports hypofractionation for small tumors treated with rotation therapy, i.e. highly conformal techniques where a large volume of lung tissue is exposed to low but nonzero dose. For larger tumors, the model suggests hyperfractionation. We further discuss several non-intuitive interdependencies between optimal fractionation and the spatial dose distribution. For instance, lowering the dose in the lung via proton therapy does not necessarily provide a biological rationale for hypofractionation.

  9. Optimization of extracranial stereotactic radiation therapy of small lung lesions using accurate dose calculation algorithms

    Directory of Open Access Journals (Sweden)

    Polednik Martin

    2006-11-01

    Full Text Available Abstract Background The aim of this study was to compare and to validate different dose calculation algorithms for the use in radiation therapy of small lung lesions and to optimize the treatment planning using accurate dose calculation algorithms. Methods A 9-field conformal treatment plan was generated on an inhomogeneous phantom with lung mimics and a soft tissue equivalent insert, mimicking a lung tumor. The dose distribution was calculated with the Pencil Beam and Collapsed Cone algorithms implemented in Masterplan (Nucletron and the Monte Carlo system XVMC and validated using Gafchromic EBT films. Differences in dose distribution were evaluated. The plans were then optimized by adding segments to the outer shell of the target in order to increase the dose near the interface to the lung. Results The Pencil Beam algorithm overestimated the dose by up to 15% compared to the measurements. Collapsed Cone and Monte Carlo predicted the dose more accurately with a maximum difference of -8% and -3% respectively compared to the film. Plan optimization by adding small segments to the peripheral parts of the target, creating a 2-step fluence modulation, allowed to increase target coverage and homogeneity as compared to the uncorrected 9 field plan. Conclusion The use of forward 2-step fluence modulation in radiotherapy of small lung lesions allows the improvement of tumor coverage and dose homogeneity as compared to non-modulated treatment plans and may thus help to increase the local tumor control probability. While the Collapsed Cone algorithm is closer to measurements than the Pencil Beam algorithm, both algorithms are limited at tissue/lung interfaces, leaving Monte-Carlo the most accurate algorithm for dose prediction.

  10. Challenges to protocol optimization due to unexpected variation of CT contrast dose amount and flow.

    Science.gov (United States)

    Robinson, Tracy J; Robinson, Jeffrey D; Hippe, Daniel S; Mitsumori, Lee M

    2013-06-01

    High-quality computed tomography (CT) exams are critical to maximizing radiologist's interpretive ability. Exam quality in part depends on proper contrast administration. We examined injector data from consecutive abdominal and pelvic CT exams to analyze variation in contrast administration. Discrepancies between intended IV contrast dose and flow rate with the actual administered contrast dose and measured flow rate were common. In particular, delivered contrast dose discrepancies of at least 10% occurred in 13% of exams while discrepancies in flow rate of at least 10% occurred in 42% of exams. Injector logs are useful for assessing and tracking this type of variability which may confound contrast administration optimization and standardization efforts.

  11. Is patient size important in dose determination and optimization in cardiology?

    Energy Technology Data Exchange (ETDEWEB)

    Reay, J; Chapple, C L; Kotre, C J [Regional Medical Physics Department, Newcastle General Hospital, Newcastle Upon Tyne, NE4 6BE (United Kingdom)

    2003-12-07

    Patient dose determination and optimization have become more topical in recent years with the implementation of the Medical Exposures Directive into national legislation, the Ionising Radiation (Medical Exposure) Regulations. This legislation incorporates a requirement for new equipment to provide a means of displaying a measure of patient exposure and introduces the concept of diagnostic reference levels. It is normally assumed that patient dose is governed largely by patient size; however, in cardiology, where procedures are often very complex, the significance of patient size is less well understood. This study considers over 9000 cardiology procedures, undertaken throughout the north of England, and investigates the relationship between patient size and dose. It uses simple linear regression to calculate both correlation coefficients and significance levels for data sorted by both room and individual clinician for the four most common examinations, left ventrical and/or coronary angiography, single vessel stent insertion and single vessel angioplasty. This paper concludes that the correlation between patient size and dose is weak for the procedures considered. It also illustrates the use of an existing method for removing the effect of patient size from dose survey data. This allows typical doses and, therefore, reference levels to be defined for the purposes of dose optimization.

  12. Dosimetric optimization of a conical breast brachytherapy applicator for improved skin dose sparing

    Energy Technology Data Exchange (ETDEWEB)

    Yang Yun; Rivard, Mark J. [Biomedical Engineering and Biotechnology, University of Massachusetts Lowell, Lowell, Massachusetts 01854 (United States); Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111 (United States)

    2010-11-15

    Purpose: Both the AccuBoost D-shaped and round applicators have been dosimetrically characterized and clinically used to treat patients with breast cancer. While the round applicators provide conformal dose coverage, under certain clinical circumstances the breast skin dose may be higher than preferred. The purpose of this study was to modify the round applicators to minimize skin dose while not substantially affecting dose uniformity within the target volume and reducing the treatment time. Methods: In order to irradiate the intended volume while sparing critical structures such as the skin, the current round applicator design has been augmented through the addition of an internal truncated cone (i.e., frustum) shield. Monte Carlo methods and clinical constraints were used to design the optimal cone applicator. With the cone applicator now defined as the entire assembly including the surrounding tungsten-alloy shell holding the HDR {sup 192}Ir source catheter, the applicator height was reduced to diminish the treatment time while minimizing skin dose. Monte Carlo simulation results were validated using both radiochromic film and ionization chamber measurements based on established techniques. Results: The optimal cone applicators diminished the maximum skin dose by 15%-32% (based on the applicator diameter and breast separation) with the tumor dose reduced by less than 3% for a constant exposure time. Furthermore, reduction in applicator height diminished the treatment time by up to 30%. Radiochromic film and ionization chamber dosimetric results in phantom agreed with Monte Carlo simulation results typically within 3%. Larger differences were outside the treatment volume in low dose regions or associated with differences between the measurement and Monte Carlo simulation environments. Conclusions: A new radiotherapy treatment device was developed and dosimetrically characterized. This set of applicators significantly reduces the skin dose and treatment time while

  13. Optimization of a conical antenna for pulse radiation - An efficient design using resistive loading

    Science.gov (United States)

    Maloney, James G.; Smith, Glenn S.

    1993-07-01

    The conical monopole antenna with a section of continuous resistive loading is considered as a radiator for temporally short, broad-bandwidth pulses. The geometrical details of the coaxial feed and the resistive loading are varied to optimize this structure for pulse radiation. Compared with the perfectly conducting cone, the optimized resistive cone radiates a better reproduction of the pulse excitation with no loss in amplitude, and has internal reflections that are much smaller in amplitude. Graphical displays of the field surrounding the antenna are used to give insight into the physical processes for transient radiation from this antenna. Experimental models were constructed to verify the optimization and demonstrate the practicality of the design. Measurements of both the reflected voltage in the feed line and the time-varying radiated field are in excellent agreement with the theoretical calculations.

  14. Optimization of Boiler Control for Improvement of Load Following Capabilities of Existing Power Plants

    DEFF Research Database (Denmark)

    Mortensen, J. H.; Mølbak, T.; Pedersen, Tom Søndergaard

    1997-01-01

    An An optimizing control system for improving the load following capabilities of power plant units has been developed. The system is implemented as a complement producing additive control signals to the existing boiler control system, a concept which has various practical advantages in terms...... of implementation and commissioning. The optimizing control system takes into account the multivariable and nonlinear characteristics of the boiler process as a gain-scheduled LQG-controller is utilized. Simulation results indicate that a reduction of steam temperature deviations of about 75% can be obtained.......optimizing control system for improving the load following capabilities of power plant units has been developed. The system is implemented as a complement producing additive control signals to the existing boiler control system, a concept which has various practical advantages in terms of implementation...

  15. Multiphysics design optimization for aerospace applications: Case study on helicopter loading hanger

    Science.gov (United States)

    Xue, Hui; Khawaja, H.; Moatamedi, M.

    2014-12-01

    This paper presents the Multiphysics technique applied in the design optimization of a loading hanger for an aerial crane. In this study, design optimization is applied on the geometric modelling of a part being used in an aerial crane operation. A set of dimensional and loading requirements are provided. Various geometric models are built using SolidWorks® Computer Aided Design (CAD) Package. In addition, Finite Element Method (FEM) is applied to study these geometric models using ANSYS® Multiphysics package. Appropriate material is chosen based on the strength to weight ratio. Efforts are made to optimize the geometry to reduce the weight of the part. Based on the achieved results, conclusions are drawn.

  16. Absence of multiple local minima effects in intensity modulated optimization with dose-volume constraints

    Energy Technology Data Exchange (ETDEWEB)

    Llacer, Jorge [EC Engineering Consultants, LLC 130, Forest Hill Drive, Los Gatos, CA (United States); Deasy, Joseph O [Department of Radiation Oncology, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO (United States); Bortfeld, Thomas R [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, 30 Fruit Street, Boston, MA (United States); Solberg, Timothy D [Department of Radiation Oncology, University of California, Los Angeles, CA (United States); Promberger, Claus [BrainLAB AG, Ammerthalstrasse 8, 85551 Heimstetten (Germany)

    2003-01-21

    This paper reports on the analysis of intensity modulated radiation treatment optimization problems in the presence of non-convex feasible parameter spaces caused by the specification of dose-volume constraints for the organs-at-risk (OARs). The main aim was to determine whether the presence of those non-convex spaces affects the optimization of clinical cases in any significant way. This was done in two phases: (1) Using a carefully designed two-dimensional mathematical phantom that exhibits two controllable minima and with randomly initialized beamlet weights, we developed a methodology for exploring the nature of the convergence characteristics of quadratic cost function optimizations (deterministic or stochastic). The methodology is based on observing the statistical behaviour of the residual cost at the end of optimizations in which the stopping criterion is progressively more demanding and carrying out those optimizations to very small error changes per iteration. (2) Seven clinical cases were then analysed with dose-volume constraints that are stronger than originally used in the clinic. The clinical cases are two prostate cases differently posed, a meningioma case, two head-and-neck cases, a spleen case and a spine case. Of the 14 different sets of optimizations (with and without the specification of maximum doses allowed for the OARs), 12 fail to show any effect due to the existence of non-convex feasible spaces. The remaining two sets of optimizations show evidence of multiple minima in the solutions, but those minima are very close to each other in cost and the resulting treatment plans are practically identical, as measured by the quality of the dose-volume histograms (DVHs). We discuss the differences between fluence maps resulting from those similar treatment plans. We provide a possible reason for the observed results and conclude that, although the study is necessarily limited, the annealing characteristics of a simulated annealing method may not be

  17. Absence of multiple local minima effects in intensity modulated optimization with dose-volume constraints

    Science.gov (United States)

    Llacer, Jorge; Deasy, Joseph O.; Bortfeld, Thomas R.; Solberg, Timothy D.; Promberger, Claus

    2003-01-01

    This paper reports on the analysis of intensity modulated radiation treatment optimization problems in the presence of non-convex feasible parameter spaces caused by the specification of dose-volume constraints for the organs-at-risk (OARs). The main aim was to determine whether the presence of those non-convex spaces affects the optimization of clinical cases in any significant way. This was done in two phases: (1) Using a carefully designed two-dimensional mathematical phantom that exhibits two controllable minima and with randomly initialized beamlet weights, we developed a methodology for exploring the nature of the convergence characteristics of quadratic cost function optimizations (deterministic or stochastic). The methodology is based on observing the statistical behaviour of the residual cost at the end of optimizations in which the stopping criterion is progressively more demanding and carrying out those optimizations to very small error changes per iteration. (2) Seven clinical cases were then analysed with dose-volume constraints that are stronger than originally used in the clinic. The clinical cases are two prostate cases differently posed, a meningioma case, two head-and-neck cases, a spleen case and a spine case. Of the 14 different sets of optimizations (with and without the specification of maximum doses allowed for the OARs), 12 fail to show any effect due to the existence of non-convex feasible spaces. The remaining two sets of optimizations show evidence of multiple minima in the solutions, but those minima are very close to each other in cost and the resulting treatment plans are practically identical, as measured by the quality of the dose-volume histograms (DVHs). We discuss the differences between fluence maps resulting from those similar treatment plans. We provide a possible reason for the observed results and conclude that, although the study is necessarily limited, the annealing characteristics of a simulated annealing method may not be

  18. Exploiting Additive Manufacturing Infill in Topology Optimization for Improved Buckling Load

    DEFF Research Database (Denmark)

    Clausen, Anders; Aage, Niels; Sigmund, Ole

    2016-01-01

    Additive manufacturing (AM) permits the fabrication of functionally optimized components with high geometrical complexity. The opportunity of using porous infill as an integrated part of the manufacturing process is an example of a unique AM feature. Automated design methods are still incapable...... addresses an important inadequacy of the standard minimum compliance topology optimization approach, in which buckling is rarely accounted for; rather, a satisfactory buckling load is usually assured through a post-processing step that may lead to sub-optimal components. The present work compares...... the standard and coating approaches to topology optimization for the MBB beam benchmark case. The optimized structures are additively manufactured using a filamentary technique. This experimental study validates the numerical model used in the coating approach. Depending on the properties of the infill...

  19. Doses optimization to patients in computed tomography studies; Optimizacion de las dosis a pacientes en estudios de tomografia computada

    Energy Technology Data Exchange (ETDEWEB)

    Trujillo Z, F. E., E-mail: flaviotrujillo@gmail.co [Hospital Regional de Alta Especialidad de Oaxaca, Aldama s/n, Paraje El Tule, 71256 San Bartolo Coyotepec, Oaxaca (Mexico)

    2010-09-15

    in recent years the number of studies of computed tomography has been increased, as well as the technology and methodology of these, while the radiological protection to the patient has not advanced to the same step. The IAEA has implemented the Patients Radiation Protection projects, where one of the areas of more interest is the computed tomography. The present work is a brief summary of the actions to realize for the doses optimization imparted to the patients, obtaining an appropriate diagnostic quality in the images at the same time; as it was presented in the course of the project C-RLA/9/067-001. The results that were obtained between Image Quality and Dose by Radiation that is imparted to the patient are shown, as well s the exposition factors that influence in these, according to the project C-RLA/9/067-001. The main actions for the dose optimization are using tension optimized protocols (kV), of load (m As), of collimation/cut thickness, of inclination of the gantry, of the pitch/displacement by rotation, of the reconstruction algorithm (kernel), according to the diagnostic objective to reach and to the patient physical characteristics (like weight and age), as well as to use protections to shield the sensitive organs (mainly those that do not have clinical interest for the procedure). Conclusion: To establish or to begin to implement, insofar as possible, the IAEA recommendations, relating to the clinical practice of the hospitals in Mexico and to the available equipment s type. (Author)

  20. An automated optimization tool for high-dose-rate (HDR) prostate brachytherapy with divergent needle pattern

    Science.gov (United States)

    Borot de Battisti, M.; Maenhout, M.; de Senneville, B. Denis; Hautvast, G.; Binnekamp, D.; Lagendijk, J. J. W.; van Vulpen, M.; Moerland, M. A.

    2015-10-01

    Focal high-dose-rate (HDR) for prostate cancer has gained increasing interest as an alternative to whole gland therapy as it may contribute to the reduction of treatment related toxicity. For focal treatment, optimal needle guidance and placement is warranted. This can be achieved under MR guidance. However, MR-guided needle placement is currently not possible due to space restrictions in the closed MR bore. To overcome this problem, a MR-compatible, single-divergent needle-implant robotic device is under development at the University Medical Centre, Utrecht: placed between the legs of the patient inside the MR bore, this robot will tap the needle in a divergent pattern from a single rotation point into the tissue. This rotation point is just beneath the perineal skin to have access to the focal prostate tumor lesion. Currently, there is no treatment planning system commercially available which allows optimization of the dose distribution with such needle arrangement. The aim of this work is to develop an automatic inverse dose planning optimization tool for focal HDR prostate brachytherapy with needle insertions in a divergent configuration. A complete optimizer workflow is proposed which includes the determination of (1) the position of the center of rotation, (2) the needle angulations and (3) the dwell times. Unlike most currently used optimizers, no prior selection or adjustment of input parameters such as minimum or maximum dose or weight coefficients for treatment region and organs at risk is required. To test this optimizer, a planning study was performed on ten patients (treatment volumes ranged from 8.5 cm3to 23.3 cm3) by using 2-14 needle insertions. The total computation time of the optimizer workflow was below 20 min and a clinically acceptable plan was reached on average using only four needle insertions.

  1. An automated optimization tool for high-dose-rate (HDR) prostate brachytherapy with divergent needle pattern

    NARCIS (Netherlands)

    Borot, Maxence; Maenhout, M.; de Senneville, B. Denis; Hautvast, G.; Binnekamp, D.; Lagendijk, J. J. W.; van Vulpen, M.; Moerland, M. A.

    2015-01-01

    Focal high-dose-rate (HDR) for prostate cancer has gained increasing interest as an alternative to whole gland therapy as it may contribute to the reduction of treatment related toxicity. For focal treatment, optimal needle guidance and placement is warranted. This can be achieved under MR guidance.

  2. Optimal Load and Stiffness for Displacement-Constrained Vibration Energy Harvesters

    CERN Document Server

    Halvorsen, Einar

    2016-01-01

    The power electronic interface to a vibration energy harvester not only provides ac-dc conversion, but can also set the electrical damping to maximize output power under displacement-constrained operation. This is commonly exploited for linear two-port harvesters by synchronous switching to realize a Coulomb-damped resonant generator, but has not been fully explored when the harvester is asynchronously switched to emulate a resistive load. In order to understand the potential of such an approach, the optimal values of load resistance and other control parameters need to be known. In this paper we determine analytically the optimal load and stiffness of a harmonically driven two-port harvester with displacement constraints. For weak-coupling devices, we do not find any benefit of load and stiffness adjustment beyond maintaining a saturated power level. For strong coupling we find that the power can be optimized to agree with the velocity damped generator beyond the first critical force for displacement-constra...

  3. Optimized loading and sustained release of hydrophilic proteins from internally nanostructured particles.

    Science.gov (United States)

    Chemelli, Angela; Maurer, Manuela; Geier, Roman; Glatter, Otto

    2012-12-11

    In this study, we demonstrate that emulsified microemulsions and micellar cubosomes are suitable as sustained delivery vehicles for water-soluble proteins. Through structural modifications, the loading efficiency of two model proteins, namely bovine serum albumin (BSA) and cytochrome c could be remarkably increased. A procedure for preparing these particles loaded with optimized amounts of sensitive substances is presented. Loading and dispersion at low temperatures is performed in two successive steps. First, a water-in-oil microemulsion is loaded with the proteins. Subsequently, this phase is dispersed in water resulting in particles with microemulsion and micellar cubic internal structure and a size of approximately 620 nm. This two-step method ensures optimal loading of the particles with the proteins. These nanostructured particles are able to sustain the release of the water-soluble BSA and cytochrome c. Within one day, less than 10% of BSA and 15% of cytochrome c are released. The release rate of cytochrome c is influenced by the nanostructure of the particles.

  4. Tools for the analysis of dose optimization: III. Pointwise sensitivity and perturbation analysis.

    Science.gov (United States)

    Sobotta, B; Söhn, M; Pütz, M; Alber, M

    2008-11-21

    The major challenge in intensity-modulated radiotherapy planning is to find the right balance between tumor control and normal tissue sparing. The most desirable solution is never physically feasible, and a compromise has to be found. One possible way to approach this problem is constrained optimization. In this context, it is worthwhile to quantitatively predict the impact of adjustments of the constraints on the optimum dose distribution. This has been dealt with in regard to cost functions in a previous paper. The aim of the present paper is to introduce spatial resolution to this formalism. Our method reveals the active constraints in a target subvolume that was previously selected by the practitioner for its insufficient dose. This is useful if a multitude of constraints can be the cause of a cold spot. The response of the optimal dose distribution to an adjustment of constraints (perturbation) is predicted. We conclude with a clinical example.

  5. Tools for the analysis of dose optimization: III. Pointwise sensitivity and perturbation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sobotta, B; Soehn, M; Puetz, M; Alber, M [Abt. Medizinische Physik, Radiologische Uniklinik, Universitaet Tuebingen, 72076 Tuebingen (Germany)], E-mail: benjamin.sobotta@med.uni-tuebingen.de

    2008-11-21

    The major challenge in intensity-modulated radiotherapy planning is to find the right balance between tumor control and normal tissue sparing. The most desirable solution is never physically feasible, and a compromise has to be found. One possible way to approach this problem is constrained optimization. In this context, it is worthwhile to quantitatively predict the impact of adjustments of the constraints on the optimum dose distribution. This has been dealt with in regard to cost functions in a previous paper. The aim of the present paper is to introduce spatial resolution to this formalism. Our method reveals the active constraints in a target subvolume that was previously selected by the practitioner for its insufficient dose. This is useful if a multitude of constraints can be the cause of a cold spot. The response of the optimal dose distribution to an adjustment of constraints (perturbation) is predicted. We conclude with a clinical example.

  6. Optimally oriented grooves on dental implants improve bone quality around implants under repetitive mechanical loading.

    Science.gov (United States)

    Kuroshima, Shinichiro; Nakano, Takayoshi; Ishimoto, Takuya; Sasaki, Muneteru; Inoue, Maaya; Yasutake, Munenori; Sawase, Takashi

    2017-01-15

    The aim was to investigate the effect of groove designs on bone quality under controlled-repetitive load conditions for optimizing dental implant design. Anodized Ti-6Al-4V alloy implants with -60° and +60° grooves around the neck were placed in the proximal tibial metaphysis of rabbits. The application of a repetitive mechanical load was initiated via the implants (50N, 3Hz, 1800 cycles, 2days/week) at 12weeks after surgery for 8weeks. Bone quality, defined as osteocyte density and degree of biological apatite (BAp) c-axis/collagen fibers, was then evaluated. Groove designs did not affect bone quality without mechanical loading; however, repetitive mechanical loading significantly increased bone-to-implant contact, bone mass, and bone mineral density (BMD). In +60° grooves, the BAp c-axis/collagen fibers preferentially aligned along the groove direction with mechanical loading. Moreover, osteocyte density was significantly higher both inside and in the adjacent region of the +60° grooves, but not -60° grooves. These results suggest that the +60° grooves successfully transmitted the load to the bone tissues surrounding implants through the grooves. An optimally oriented groove structure on the implant surface was shown to be a promising way for achieving bone tissue with appropriate bone quality. This is the first report to propose the optimal design of grooves on the necks of dental implants for improving bone quality parameters as well as BMD. The findings suggest that not only BMD, but also bone quality, could be a useful clinical parameter in implant dentistry.

  7. Optimal scheduling of biocide dosing for seawater-cooled power and desalination plants

    KAUST Repository

    Mahfouz, Abdullah Bin

    2011-02-13

    Thermal desalination systems are typically integrated with power plants to exploit the excess heat resulting from the power-generation units. Using seawater in cooling the power plant and the desalination system is a common practice in many parts of the world where there is a shortage of freshwater. Biofouling is one of the major problems associated with the usage of seawater in cooling systems. Because of the dynamic variation in the power and water demands as well as the changes in the characteristics of seawater and the process, there is a need to develop an optimal policy for scheduling biocide usage and cleaning maintenance of the heat exchangers. The objective of this article is to introduce a systematic procedure for the optimization of scheduling the dosing of biocide and dechlorination chemicals as well as cleaning maintenance for a power production/thermal desalination plant. A multi-period optimization formulation is developed and solved to determine: the optimal levels of dosing and dechlorination chemicals; the timing of maintenance to clean the heat-exchange surfaces; and the dynamic dependence of the biofilm growth on the applied doses, the seawater-biocide chemistry, the process conditions, and seawater characteristics for each time period. The technical, economic, and environmental considerations of the system are accounted for. A case study is solved to elucidate the applicability of the developed optimization approach. © 2011 Springer-Verlag.

  8. Optimization of Boiler Control to Improve the Load-following Capability of Power-plant Units

    DEFF Research Database (Denmark)

    Mortensen, J. H.; Mølbak, T.; Andersen, Palle;

    1998-01-01

    therefore been developed. The system is implemented as a complement, producing control signals to be added to those of the existing boiler control system, a concept which has various practical advantages in terms of implementation and commissioning. The optimizing control system takes account...... of the multivariable and load-de*pendent nonlinear characteristics of the boiler process, as a scheduled LQG controller with feedforward action is utilized. The LQG controller improves the control of critical pro*cess variables, making it possible to increase the load-following capability of a specific plant. Field...

  9. Optimization of Boiler Control to Improve the Load-following Capability of Power-plant Units

    DEFF Research Database (Denmark)

    Mortensen, J. H.; Mølbak, T.; Andersen, Palle;

    therefore been developed. The system is implemented as a complement, producing control signals to be added to those of the existing boiler control system, a concept which has various practical advantages in terms of implementation and commissioning. The optimizing control system takes account...... of the multivariable and load-de*pendent nonlinear characteristics of the boiler process, as a scheduled LQG controller with feedforward action is utilized. The LQG controller improves the control of critical pro*cess variables, making it possible to increase the load-following capability of a specific plant. Field...

  10. Optimal design method to minimize users' thinking mapping load in human-machine interactions.

    Science.gov (United States)

    Huang, Yanqun; Li, Xu; Zhang, Jie

    2015-01-01

    The discrepancy between human cognition and machine requirements/behaviors usually results in serious mental thinking mapping loads or even disasters in product operating. It is important to help people avoid human-machine interaction confusions and difficulties in today's mental work mastered society. Improving the usability of a product and minimizing user's thinking mapping and interpreting load in human-machine interactions. An optimal human-machine interface design method is introduced, which is based on the purpose of minimizing the mental load in thinking mapping process between users' intentions and affordance of product interface states. By analyzing the users' thinking mapping problem, an operating action model is constructed. According to human natural instincts and acquired knowledge, an expected ideal design with minimized thinking loads is uniquely determined at first. Then, creative alternatives, in terms of the way human obtains operational information, are provided as digital interface states datasets. In the last, using the cluster analysis method, an optimum solution is picked out from alternatives, by calculating the distances between two datasets. Considering multiple factors to minimize users' thinking mapping loads, a solution nearest to the ideal value is found in the human-car interaction design case. The clustering results show its effectiveness in finding an optimum solution to the mental load minimizing problems in human-machine interaction design.

  11. Optimality study of a gust alleviation system for light wing-loading STOL aircraft

    Science.gov (United States)

    Komoda, M.

    1976-01-01

    An analytical study was made of an optimal gust alleviation system that employs a vertical gust sensor mounted forward of an aircraft's center of gravity. Frequency domain optimization techniques were employed to synthesize the optimal filters that process the corrective signals to the flaps and elevator actuators. Special attention was given to evaluating the effectiveness of lead time, that is, the time by which relative wind sensor information should lead the actual encounter of the gust. The resulting filter is expressed as an implicit function of the prescribed control cost. A numerical example for a light wing loading STOL aircraft is included in which the optimal trade-off between performance and control cost is systematically studied.

  12. Optimal Distribution of Viscoelastic Dampers under Elastic Finite Beam under Moving Load

    Directory of Open Access Journals (Sweden)

    Khurshudyan Am. Zh.

    2014-09-01

    Full Text Available The problem of viscoelastic dampers optimal distribution function determination is investigated under simply supported elastic beam of finite length, subjected to a moving load with constant intensity, moving along the beam with constant velocity. Our main aim is the dampers optimal distribution function determination, and optimality criterion– the density of that distribution. Problem is mathematically formulated as initial–boundary problem for bilinear wave equation with variable controllable coefficient. Application of Bubnov–Gelerkin procedure allow us to reduce solution of the problem to finite–dimensional moments problem, which is resolved explicitly. It is proved, that optimal in mentioned sense is dampers discrete (pointwise distribution. Approximating function of beam deflection is deter-mined. Results of numerical calculations are presented.

  13. Cost optimization of load carrying thin-walled precast high performance concrete sandwich panels

    DEFF Research Database (Denmark)

    Hodicky, Kamil; Hansen, Sanne; Hulin, Thomas

    2015-01-01

    and HPCSP’s geometrical parameters as well as on material cost function in the HPCSP design. Cost functions are presented for High Performance Concrete (HPC), insulation layer, reinforcement and include labour-related costs. The present study reports the economic data corresponding to specific manufacturing......The paper describes a procedure to find the structurally and thermally efficient design of load-carrying thin-walled precast High Performance Concrete Sandwich Panels (HPCSP) with an optimal economical solution. A systematic optimization approach is based on the selection of material’s performances....... The solution of the optimization problem is performed in the computer package software Matlab® with SQPlab package and integrates the processes of HPCSP design, quantity take-off and cost estimation. The proposed optimization process outcomes in complex HPCSP design proposals to achieve minimum cost of HPCSP....

  14. The pharmacokinetics of vancomycin during the initial loading dose in patients with septic shock

    Science.gov (United States)

    Katip, Wasan; Jaruratanasirikul, Sutep; Pattharachayakul, Sutthiporn; Wongpoowarak, Wibul; Jitsurong, Arnurai; Lucksiri, Aroonrut

    2016-01-01

    Objective To characterize the pharmacokinetics (PK) of vancomycin in patients in the initial phase of septic shock. Methods Twelve patients with septic shock received an intravenous infusion of vancomycin 30 mg/kg over 2 h. The vancomycin PK study was conducted during the first 12 h of the regimen. Serum vancomycin concentration–time data were analyzed using the standard model-independent analysis and the compartment model. Results For the noncompartment analysis the mean values ± standard deviation (SD) of the estimated clearance and volume of distribution of vancomycin at steady state were 6.05±1.06 L/h and 78.73±21.78 L, respectively. For the compartmental analysis, the majority of vancomycin concentration–time profiles were best described by a two-compartment PK model. Thus, the two-compartmental first-order elimination model was used for the analysis. The mean ± SD of the total clearance (3.70±1.25 L/h) of vancomycin was higher than that obtained from patients without septic shock. In contrast, the volume of the central compartment (8.34±4.36 L) and volume of peripheral compartment (30.99±7.84 L) did not increase when compared with patients without septic shock. Conclusion The total clearance of vancomycin was increased in septic shock patients. However, the volume of the central compartment and peripheral compartment did not increase. Consequently, a loading dose of vancomycin should be considered in all patients with septic shock. PMID:27920562

  15. Fuzzy Adaptive Particle Swarm Optimization for Power Loss Minimisation in Distribution Systems Using Optimal Load Response

    DEFF Research Database (Denmark)

    Hu, Weihao; Chen, Zhe; Bak-Jensen, Birgitte;

    2014-01-01

    power loss minimization in distribution systems. In this paper, a new method to achieve power loss minimization in distribution systems by using a price signal to guide the demand side management is proposed. A fuzzy adaptive particle swarm optimization (FAPSO) is used as a tool for the power loss...... minimization study. Simulation results show that the proposed approach is an effective measure to achieve power loss minimization in distribution systems....

  16. A mathematical approach to optimizing the radiation dose distribution in heterogeneous tumours

    Energy Technology Data Exchange (ETDEWEB)

    Stavreva, N.A. [Waikato Univ., Hamilton (New Zealand). Dept. of Physics; Stavrev, P.V. [Waikato Univ., Hamilton (New Zealand). Dept. of Physics; Round, W.H. [Waikato Univ., Hamilton (New Zealand). Dept. of Physics

    1996-12-31

    This paper offers a general mathematical approach to dose distribution optimization which allows tumours with different degrees of complexity to be considered. Two different biological criteria - (A) keeping the control probability of the different parts of the tumour (local tumour control probability) uniform throughout the tumour and (B) minimizing the mean dose delivered to the tumour are studied. For both criteria we impose the requirement that the whole tumour control probability be kept on a certain desired level. It is proved that the adoption of the first criterion requires a dose distribution logarithmic with the cell density and proportional to the inverse of the cell radiosensitivity while the adoption of the second criterion necessitates a homogeneous dose distribution when the cell radiosensitivity is constant. The corresponding formula for the dose distribution in case of heterogeneous cell radiosensitivity is also given. The two criteria are compared in terms of local tumour control probability and mean dose delivered to the tumour. It is concluded that maintaining constant local tumour control probability (criterion A) may be of greater clinical importance then minimizing the mean dose (criterion B). (orig.).

  17. Development of optimal kids insulin dosing system formulas for young children with type 1 diabetes mellitus.

    Science.gov (United States)

    Alemzadeh, Ramin; Hoffmann, Raymond G; Dasgupta, Mahua; Parton, Elaine

    2012-05-01

    This study was designed to develop predictive formulas for precise insulin dosing in young children with type 1 diabetes (T1DM). Consecutive 1-year data from a group of 14 young patients (eight girls, six boys) 3.9 ± 0.8 years old with diabetes duration of 2.0 ± 0.8 years, transitioned from multiple daily injections (MDI) to continuous subcutaneous insulin infusion (CSII), were analyzed to identify parameters governing optimal insulin dosing. Body mass index (BMI), total daily dose (TDD), total basal dose, insulin-to-carbohydrate ratio (ICR), correction factor (CF), and mean amplitude of glycemic excursion (MAGE) by continuous glucose monitoring and hemoglobin A(1c) (HbA(1c)) level were evaluated at baseline and every 3 months. The slopes of CF versus 1/TDD, bolus versus TDD, ICR versus 1/TDD, and CF versus ICR were determined. Kids Insulin Dosing System (KIDS) slope constants at follow-up were associated with MAGE compared with baseline (PKIDS formulas estimated TDD=0.74×body weight, total basal dose=0.28×TDD, CF=2,800/TDD, and ICR=13.5×body weight/TDD. The interrelationships among ICR, CF, TBD, and TDD remained stable on CSII and were accompanied by decreased glycemic excursions. The KIDS formulas may yield consistent and easy estimates of insulin dosing factors in very young patients with T1DM.

  18. Simultaneous optimization of the cavity heat load and trip rates in linacs using a genetic algorithm

    Directory of Open Access Journals (Sweden)

    Balša Terzić

    2014-10-01

    Full Text Available In this paper, a genetic algorithm-based optimization is used to simultaneously minimize two competing objectives guiding the operation of the Jefferson Lab’s Continuous Electron Beam Accelerator Facility linacs: cavity heat load and radio frequency cavity trip rates. The results represent a significant improvement to the standard linac energy management tool and thereby could lead to a more efficient Continuous Electron Beam Accelerator Facility configuration. This study also serves as a proof of principle of how a genetic algorithm can be used for optimizing other linac-based machines.

  19. Optimal Adaptive Droop Control for Effective Load Sharing in AC Microgrids

    DEFF Research Database (Denmark)

    Anvari-Moghaddam, Amjad; Shafiee, Qobad; Quintero, Juan Carlos Vasquez

    2016-01-01

    scheme. However, sharing powers among the sources based on the units’ rated capacities is not an optimal solution in terms of economy and efficiency. In this paper, a new adaptive droop-based control strategy is proposed for AC MGs to optimally share MG load between corresponding units. The mentioned......During the past few years, microgrids (MGs) have been becoming more attractive as effective means to integrate different distributed energy resources (DERs). To coordinate active and reactive power sharing among DERs, conventional droop control method is widely used as a decentralized control...

  20. Experimental characterization and multidisciplinary conceptual design optimization of a bendable load stiffened unmanned air vehicle wing

    Science.gov (United States)

    Jagdale, Vijay Narayan

    Demand for deployable MAVs and UAVs with wings designed to reduce aircraft storage volume led to the development of a bendable wing concept at the University of Florida (UF). The wing shows an ability to load stiffen in the flight load direction, still remaining compliant in the opposite direction, enabling UAV storage inside smaller packing volumes. From the design prospective, when the wing shape parameters are treated as design variables, the performance requirements : high aerodynamic efficiency, structural stability under aggressive flight loads and desired compliant nature to prevent breaking while stored, in general conflict with each other. Creep deformation induced by long term storage and its effect on the wing flight characteristics are additional considerations. Experimental characterization of candidate bendable UAV wings is performed in order to demonstrate and understand aerodynamic and structural behavior of the bendable load stiffened wing under flight loads and while the wings are stored inside a canister for long duration, in the process identifying some important wing shape parameters. A multidisciplinary, multiobjective design optimization approach is utilized for conceptual design of a 24 inch span and 7 inch root chord bendable wing. Aerodynamic performance of the wing is studied using an extended vortex lattice method based Athena Vortex Lattice (AVL) program. An arc length method based nonlinear FEA routine in ABAQUS is used to evaluate the structural performance of the wing and to determine maximum flying velocity that the wing can withstand without buckling or failing under aggressive flight loads. An analytical approach is used to study the stresses developed in the composite wing during storage and Tsai-Wu criterion is used to check failure of the composite wing due to the rolling stresses to determine minimum safe storage diameter. Multidisciplinary wing shape and layup optimization is performed using an elitist non-dominated sorting

  1. Toward endobronchial Ir-192 high-dose-rate brachytherapy therapeutic optimization

    Energy Technology Data Exchange (ETDEWEB)

    Gay, H A [Department of Radiation Oncology, Brody School of Medicine at East Carolina University, Greenville, NC (United States); Allison, R R [Department of Radiation Oncology, Brody School of Medicine at East Carolina University, Greenville, NC (United States); Downie, G H [Section of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Brody School of Medicine at East Carolina University, Greenville, NC (United States); Mota, H C [Department of Radiation Oncology, Brody School of Medicine at East Carolina University, Greenville, NC (United States); Austerlitz, C [Department of Radiation Oncology, Brody School of Medicine at East Carolina University, Greenville, NC (United States); Jenkins, T [Department of Radiation Oncology, Brody School of Medicine at East Carolina University, Greenville, NC (United States); Sibata, C H [Department of Radiation Oncology, Brody School of Medicine at East Carolina University, Greenville, NC (United States)

    2007-06-07

    A number of patients with lung cancer receive either palliative or curative high-dose-rate (HDR) endobronchial brachytherapy. Up to a third of patients treated with endobronchial HDR die from hemoptysis. Rather than accept hemoptysis as an expected potential consequence of HDR, we have calculated the radial dose distribution for an Ir-192 HDR source, rigorously examined the dose and prescription points recommended by the American Brachytherapy Society (ABS), and performed a radiobiological-based analysis. The radial dose rate of a commercially available Ir-192 source was calculated with a Monte Carlo simulation. Based on the linear quadratic model, the estimated palliative, curative and blood vessel rupture radii from the center of an Ir-192 source were obtained for the ABS recommendations and a series of customized HDR prescriptions. The estimated radius at risk for blood vessel perforation for the ABS recommendations ranges from 7 to 9 mm. An optimized prescription may in some situations reduce this radius to 4 mm. The estimated blood perforation radius is generally smaller than the palliative radius. Optimized and individualized endobronchial HDR prescriptions are currently feasible based on our current understanding of tumor and normal tissue radiobiology. Individualized prescriptions could minimize complications such as fatal hemoptysis without sacrificing efficacy. Fiducial stents, HDR catheter centering or spacers and the use of CT imaging to better assess the relationship between the catheter and blood vessels promise to be useful strategies for increasing the therapeutic index of this treatment modality. Prospective trials employing treatment optimization algorithms are needed.

  2. A dose optimization method for electron radiotherapy using randomized aperture beams.

    Science.gov (United States)

    Engel, Konrad; Gauer, Tobias

    2009-09-01

    The present paper describes the entire optimization process of creating a radiotherapy treatment plan for advanced electron irradiation. Special emphasis is devoted to the selection of beam incidence angles and beam energies as well as to the choice of appropriate subfields generated by a refined version of intensity segmentation and a novel random aperture approach. The algorithms have been implemented in a stand-alone programme using dose calculations from a commercial treatment planning system. For this study, the treatment planning system Pinnacle from Philips has been used and connected to the optimization programme using an ASCII interface. Dose calculations in Pinnacle were performed by Monte Carlo simulations for a remote-controlled electron multileaf collimator (MLC) from Euromechanics. As a result, treatment plans for breast cancer patients could be significantly improved when using randomly generated aperture beams. The combination of beams generated through segmentation and randomization achieved the best results in terms of target coverage and sparing of critical organs. The treatment plans could be further improved by use of a field reduction treatment plans could be further improved by use of a field reduction algorithm. Without a relevant loss in dose distribution, the total number of MLC fields and monitor units could be reduced by up to 20%. In conclusion, using randomized aperture beams is a promising new approach in radiotherapy and exhibits potential for further improvements in dose optimization through a combination of randomized electron and photon aperture beams.

  3. Optimal control based dynamics exploration of a rigid car with load transfer

    CERN Document Server

    Rucco, Alessandro; Hauser, John

    2011-01-01

    In this paper we provide optimal control based strategies to explore the dynamic capabilities of a single-track rigid car which includes tire models and load transfer. Using an explicit formulation of the holonomic constraints imposed on the unconstrained rigid car, we design a car model which includes load transfer without adding suspension models. With this model in hand, we perform an analysis of the equilibrium manifold of the vehicle. That is, we design a continuation and predictor-corrector numerical strategy to compute cornering equilibria on the entire range of operation of the tires. Finally, as main contribution of the paper, we explore the system dynamics by use of novel nonlinear optimal control techniques. The proposed strategies allow to compute aggressive car trajectories and study how the vehicle behaves depending on its parameters. To show the effectiveness of the proposed strategies we compute aggressive maneuvers of the vehicle inspired to testing maneuvers from virtual and real prototyping...

  4. Analysis of Cell Load Coupling for LTE Network Planning and Optimization

    CERN Document Server

    Siomina, Iana

    2012-01-01

    System-centric modeling and analysis are of key significance in planning and optimizing cellular networks. In this paper, we provide a mathematical analysis of performance modeling for LTE networks. The system model characterizes the coupling relation between the cell load factors, taking into account non-uniform traffic demand and interference between the cells with arbitrary network topology. Solving the model enables a network-wide performance evaluation in resource consumption. We develop and prove both sufficient and necessary conditions for the feasibility of the load-coupling system, and provide results related to computational aspects for numerically approaching the solution. The theoretical findings are accompanied with experimental results to instructively illustrate the application in optimizing LTE network configuration.

  5. An Optimal Control Approach for an Overall Cryogenic Plant Under Pulsed Heat Loads

    CERN Document Server

    Gómez Palacin, Luis; Blanco Viñuela, Enrique; Maekawa, Ryuji; Chalifour, Michel

    2015-01-01

    This work deals with the optimal management of a cryogenic plant composed by parallel refrigeration plants, which provide supercritical helium to pulsed heat loads. First, a data reconciliation approach is proposed to estimate precisely the refrigerator variables necessary to deduce the efficiency of each refrigerator. Second, taking into account these efficiencies, an optimal operation of the system is proposed and studied. Finally, while minimizing the power consumption of the refrigerators, the control system maintains stable operation of the cryoplant under pulsed heat loads. The management of the refrigerators is carried out by an upper control layer, which balances the relative production of cooling power in each refrigerator. In addition, this upper control layer deals with the mitigation of malfunctions and faults in the system. The proposed approach has been validated using a dynamic model of the cryoplant developed with EcosimPro software, based on first principles (mass and energy balances) and the...

  6. Optimization of Boiler Heat Load in Water-Heating Boiler-House

    Directory of Open Access Journals (Sweden)

    B. A. Bayrashevsky

    2009-01-01

    Full Text Available An analytical method for optimization of water-heating boiler loads has been developed on the basis of approximated semi-empirical dependences pertaining to changes of boiler gross efficiency due to its load. A complex (∂tух/∂ξΔξ is determined on the basis of a systematic analysis (monitoring of experimental data and the Y. P. Pecker’s formula for calculation of balance losses q2. This complex makes it possible to set a corresponding correction to a standard value of the boiler gross efficiency due to contamination of heating surfaces.Software means for optimization of water-heating boilers has been developed and it is recommended to be applied under operational conditions.

  7. Parameter uncertainty-based pattern identification and optimization for robust decision making on watershed load reduction

    Science.gov (United States)

    Jiang, Qingsong; Su, Han; Liu, Yong; Zou, Rui; Ye, Rui; Guo, Huaicheng

    2017-04-01

    Nutrients loading reduction in watershed is essential for lake restoration from eutrophication. The efficient and optimal decision-making on loading reduction is generally based on water quality modeling and the quantitative identification of nutrient sources at the watershed scale. The modeling process is influenced inevitably by inherent uncertainties, especially by uncertain parameters due to equifinality. Therefore, the emerging question is: if there is parameter uncertainty, how to ensure the robustness of the optimal decisions? Based on simulation-optimization models, an integrated approach of pattern identification and analysis of robustness was proposed in this study that focuses on the impact of parameter uncertainty in water quality modeling. Here the pattern represents the discernable regularity of solutions for load reduction under multiple parameter sets. Pattern identification is achieved by using a hybrid clustering analysis (i.e., Ward-Hierarchical and K-means), which was flexible and efficient in analyzing Lake Bali near the Yangtze River in China. The results demonstrated that urban domestic nutrient load is the most potential source that should be reduced, and there are two patterns for Total Nitrogen (TN) reduction and three patterns for Total Phosphorus (TP) reduction. The patterns indicated different total reduction of nutrient loads, which reflect diverse decision preferences. The robust solution was identified by the highest accomplishment with the water quality at monitoring stations that were improved uniformly with this solution. We conducted a process analysis of robust decision-making that was based on pattern identification and uncertainty, which provides effective support for decision-making with preference under uncertainty.

  8. Application of Cat Swarm Optimization in testing Static Load Models for Voltage Stability

    Directory of Open Access Journals (Sweden)

    G. Naveen Kumar

    2016-03-01

    Full Text Available Power System Load Modeling is a method which is used to model the power system and essential for voltage stability studies. Voltage stability defines the ability of a power network to maintain steady state voltages at all the buses under normal operating conditions, and when subjected to a disturbance. The research presented as part of this paper, deals with analysis of different static load models for voltage stability studies. The precision of the results are directly related to the load models used in this analysis. The method is analyzed using continuation power flow routine. Flexible AC Transmission System technology with a combination of Cat Swarm Optimization Meta Heuristic Search approach is applied to give a solution for the problem of instability. The effectiveness of the proposed method is demonstrated through quantitative simulation on standard IEEE 14 bus system for contingency condition.

  9. Optimization, formulation, and characterization of multiflavonoids-loaded flavanosome by bulk or sequential technique

    Science.gov (United States)

    Karthivashan, Govindarajan; Masarudin, Mas Jaffri; Kura, Aminu Umar; Abas, Faridah; Fakurazi, Sharida

    2016-01-01

    This study involves adaptation of bulk or sequential technique to load multiple flavonoids in a single phytosome, which can be termed as “flavonosome”. Three widely established and therapeutically valuable flavonoids, such as quercetin (Q), kaempferol (K), and apigenin (A), were quantified in the ethyl acetate fraction of Moringa oleifera leaves extract and were commercially obtained and incorporated in a single flavonosome (QKA–phosphatidylcholine) through four different methods of synthesis – bulk (M1) and serialized (M2) co-sonication and bulk (M3) and sequential (M4) co-loading. The study also established an optimal formulation method based on screening the synthesized flavonosomes with respect to their size, charge, polydispersity index, morphology, drug–carrier interaction, antioxidant potential through in vitro 1,1-diphenyl-2-picrylhydrazyl kinetics, and cytotoxicity evaluation against human hepatoma cell line (HepaRG). Furthermore, entrapment and loading efficiency of flavonoids in the optimal flavonosome have been identified. Among the four synthesis methods, sequential loading technique has been optimized as the best method for the synthesis of QKA–phosphatidylcholine flavonosome, which revealed an average diameter of 375.93±33.61 nm, with a zeta potential of −39.07±3.55 mV, and the entrapment efficiency was >98% for all the flavonoids, whereas the drug-loading capacity of Q, K, and A was 31.63%±0.17%, 34.51%±2.07%, and 31.79%±0.01%, respectively. The in vitro 1,1-diphenyl-2-picrylhydrazyl kinetics of the flavonoids indirectly depicts the release kinetic behavior of the flavonoids from the carrier. The QKA-loaded flavonosome had no indication of toxicity toward human hepatoma cell line as shown by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide result, wherein even at the higher concentration of 200 µg/mL, the flavonosomes exert >85% of cell viability. These results suggest that sequential loading technique may be a

  10. Optimization of moderated targets loading in LMFBR for minor actinides incineration

    Energy Technology Data Exchange (ETDEWEB)

    Wu Hongchun; Takeda, Toshikazu [Osaka Univ., Suita (Japan). Dept. of Nuclear Engineering

    1999-04-01

    Optimization of moderated targets loading in LMFBR for minor actinides (MAs) incineration has been performed in this paper. Results of many different composition ratios of moderated target mixture were compared. An optimum case was proposed which can offer good core performance and transmute MAs by about 73 percent (386 kg) and incinerate MAs by about 34 percent (181 kg) through 3 years of reactor operation. (author)

  11. Optimal load balancing leveling method for multi-leg flexible platforms

    Science.gov (United States)

    Gang, Xianyue; Chai, Shan

    2013-09-01

    The working platforms supported with multiple extensible legs must be leveled before they come into operation. Although the supporting stiffness and reliability of the platform are improved with the increasing number of the supporting legs, the increased overdetermination of the multi-leg platform systems leads to leveling coupling problem among legs and virtual leg problem in which some of the supporting legs bear zero or quasi zero loads. These problems make it quite complex and time consuming to level such a multi-leg platform. Based on rigid body kinematics, an approximate equation is formulated to rapidly calculate the leg extension for leveling a rigid platform, then a proportional speed control strategy is proposed to reduce the unexpected platform distortion and leveling coupling between supporting legs. Taking both the load coupling between supporting legs and the elastic flexibility of the working platform into consideration, an optimal balancing legs’ loads(OBLL) model is firstly put forward to deal with the traditional virtual leg problem. By taking advantage of the concept of supporting stiffness matrix, a coupling extension method(CEM) is developed to solve this OBLL problem for multi-leg flexible platform. At the end, with the concept of supporting stiffness matrix and static transmissibility matrix, an optimal load balancing leveling method is proposed to achieve geometric leveling and legs’ loads balancing simultaneously. Three numerical examples are given out to illustrate the performance of proposed methods. This paper proposes a method which can effectively quantify all of the legs’ extension at the same time, achieve geometric leveling and legs’ loads balancing simultaneously. By using the proposed methods, the stability, precision and efficiency of auto-leveling control process can be improved.

  12. Real-time inverse high-dose-rate brachytherapy planning with catheter optimization by compressed sensing-inspired optimization strategies

    Science.gov (United States)

    Guthier, C. V.; Aschenbrenner, K. P.; Müller, R.; Polster, L.; Cormack, R. A.; Hesser, J. W.

    2016-08-01

    This paper demonstrates that optimization strategies derived from the field of compressed sensing (CS) improve computational performance in inverse treatment planning (ITP) for high-dose-rate (HDR) brachytherapy. Following an approach applied to low-dose-rate brachytherapy, we developed a reformulation of the ITP problem with the same mathematical structure as standard CS problems. Two greedy methods, derived from hard thresholding and subspace pursuit are presented and their performance is compared to state-of-the-art ITP solvers. Applied to clinical prostate brachytherapy plans speed-up by a factor of 56-350 compared to state-of-the-art methods. Based on a Wilcoxon signed rank-test the novel method statistically significantly decreases the final objective function value (p  <  0.01). The optimization times were below one second and thus planing can be considered as real-time capable. The novel CS inspired strategy enables real-time ITP for HDR brachytherapy including catheter optimization. The generated plans are either clinically equivalent or show a better performance with respect to dosimetric measures.

  13. Influence of optimizing protocol choice on the integral dose value in prostate radiotherapy planning by dynamic techniques - Pilot study.

    Science.gov (United States)

    Zaleska, Anna; Bogaczyk, Krzysztof; Piotrowski, Tomasz

    2017-01-01

    The purpose of this study was to compare the values of integral dose, calculated for treatment plans of dynamic radiotherapy techniques prepared with two different optimization protocols. Delivering radiation by IMRT, VMAT and also HT techniques has an influence on the low dose deposition of large areas of the patient body. Delivery of low dose can induce injury of healthy cells. In this situation, a good solution would be to reduce the area, which receives a low dose, but with appropriate dose level for the target volume. To calculate integral dose values of plans structures, we used 90 external beam radiotherapy plans prepared for three techniques (intensity modulated radiotherapy, volumetric modulated arc therapy and helical tomotherapy). One technique includes three different geometry combinations. 45 plans were prepared with classic optimization protocol and 45 with rings optimization protocol which should reduce the low doses in the normal tissue. Differences in values of the integral dose depend on the geometry and technique of irradiation, as well as optimization protocol used in preparing treatment plans. The application of the rings optimization caused the value of normal tissue integral dose (NTID) to decrease. It is possible to limit the area of low dose irradiation and reduce NTID in dynamic techniques with the same clinical constraints for OAR and PTV volumes by using an optimization protocol other than the classic one.

  14. An optimal hydropower contract load determination method considering both human and riverine ecosystem needs

    Science.gov (United States)

    Yin, Xin'an; Yang, Zhifeng; Liu, Cailing; Zhao, Yanwei

    2015-09-01

    In this research, a new method is developed to determine the optimal contract load for a hydropower reservoir, which is achieved by incorporating environmental flows into the determination process to increase hydropower revenues, while mitigating the negative impacts of hydropower generation on riverine ecosystems. In this method, the degree of natural flow regime alteration is adopted as a constraint of hydropower generation to protect riverine ecosystems, and the maximization of mean annual revenue is set as the optimization objective. The contract load in each month and the associated reservoir operating parameters were simultaneously optimized by a genetic algorithm. The proposed method was applied to China's Wangkuai Reservoir to test its effectiveness. The new method offers two advantages over traditional studies. First, it takes into account both the economic benefits and the ecological needs of riverine systems, rather than only the economic benefits, as in previous methods. Second, although many measures have been established to mitigate the negative ecological impacts of hydropower generation, few have been applied to the hydropower planning stage. Thus, since the contract load is an important planning parameter for hydropower generation, influencing both economic benefits and riverine ecosystem protection, this new method could provide guidelines for the establishment of river protection measures at the hydropower planning stage.

  15. Cuckoo Genetic Optimization Algorithm for Efficient Job Scheduling with Load Balance in Grid Computing

    Directory of Open Access Journals (Sweden)

    Rachhpal Singh

    2016-08-01

    Full Text Available Grid computing incorporates dispersed resources to work out composite technical, industrial, and business troubles. Thus a capable scheduling method is necessary for obtaining the objectives of grid. The disputes of parallel computing are commencing with the computing resources for the number of jobs and intricacy, craving, resource malnourishment, load balancing and efficiency. The risk stumbling upon parallel computing is the enthusiasm to scrutinize different optimization techniques to achieve the tasks without unsafe surroundings. Here Cuckoo Genetic Optimization Algorithm (CGOA is established that was motivated from cuckoo optimization algorithm (COA and genetic algorithm (GA for task scheduling in parallel environment (grid computing system. This CGOA is implemented on parallel dealing out for effective scheduling of multiple tasks with less schedule length and load balance. Here transmission time is evaluated with number of job set. This is computed with the help of job-processor relationship. This technique handles the issues well and the results show that complexity, load balance and resource utilization are finely managed.

  16. Optimization of dose in computerized radiology exams of the hands; Otimizacao da dose em exames de radiologia computadorizada de mao

    Energy Technology Data Exchange (ETDEWEB)

    Pavan, Ana Luiza Menegatti; Alvarez, Matheus; Alves, Allan Felipe Fattori; Dela Rosa, Maria Eugenia; Miranda, Jose Ricardo de Arruda, E-mail: analuiza@ibb.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (IBB/UNESP), Botucatu, SP (Brazil). Inst. de Biofisica. Departamento de Fisica e Biofisica; Pina, Diana Rodrigues de; Ribeiro, Sergio Marrone [Universidade Estadual Paulista Julio de Mesquita Filho (FMB/UNESP), Botucatu, SP (Brazil). Fac. de Medicina. Dept. de Doencas Tropicais e Diagnostico por Imagem; Duarte, Sergio Barbosa [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)

    2014-07-01

    Fractures and dislocations of the hand are some of the most frequently encountered injuries of the musculoskeletal system traumas. To evaluate these lesions radiography is the investigation of choice, and is rarely needed the help of other images to establish the diagnosis and treatment. The image quality of the X-ray examination is therefore essential. In this study a homogeneous phantom hand was developed for use in the hand image optimization process. In this procedure were quantified for different tissue thicknesses which are an anthropomorphic hand phantom. To perform the classification and quantification of tissue was applied membership functions in histograms of CT scans. The same procedure was adopted for 30 retrospective examinations of patients in the Hospital of the Faculty of Medicine of Botucatu UNESP (HCFMB-UNESP). The homogeneous phantom built was used to calibrate the techniques used in clinical routine (RC). Such calibrated techniques were used to acquire images of anthropomorphic phantom. These images were analyzed by Visual Grading Method (VFA) by experienced radiologists in the area. The image with better grade in AGV and lower dose was chosen as the Gold Standard. The results showed concordance between the tissue thicknesses which constitute the anthropomorphic phantom and the sample evaluated patients, with variations between 12.63% and 6.48% for soft tissue and bone, respectively. The Gold Technical Standard compared with the technique normally used in the CR reduces dose charge 41.28% and 33.18% in the tube.

  17. Use of Dose watch as a tool for the optimization of the dose in TCGMC; Uso de Dosewatch como herramienta para la optimizacion de la dosis en TCHMC

    Energy Technology Data Exchange (ETDEWEB)

    Ambroa Rey, E. M.; Vazquez Vazquez, R.; Gimenez Insua, M.; Sanchez Garcia, M.; Otero Martinez, C.; Luna Vega, V.; Mosquera sueiro, J.; Lobato Busto, R.; Pombar Camean, M.

    2013-07-01

    Computed tomography (CT) is the imaging modality that contributes most to the growth of exposure to ionizing radiation from medical imaging, representing 12% of imaging procedures using ionizing radiation, but helps with 46% of the collective dose to the population. The objective of this study is to demonstrate the usefulness of the software DoseWatch for the study and optimization of the dose in scans of TCHMC. (Author)

  18. Novel modeling framework to guide design of optimal dosing strategies for β-lactamase inhibitors.

    Science.gov (United States)

    Bhagunde, Pratik; Chang, Kai-Tai; Hirsch, Elizabeth B; Ledesma, Kimberly R; Nikolaou, Michael; Tam, Vincent H

    2012-05-01

    The scarcity of new antibiotics against drug-resistant bacteria has led to the development of inhibitors targeting specific resistance mechanisms, which aim to restore the effectiveness of existing agents. However, there are few guidelines for the optimal dosing of inhibitors. Extending the utility of mathematical modeling, which has been used as a decision support tool for antibiotic dosing regimen design, we developed a novel mathematical modeling framework to guide optimal dosing strategies for a beta-lactamase inhibitor. To illustrate our approach, MK-7655 was used in combination with imipenem against a clinical isolate of Klebsiella pneumoniae known to produce KPC-2. A theoretical concept capturing fluctuating susceptibility over time was used to define a novel pharmacodynamic index (time above instantaneous MIC [T>MIC(i)]). The MK-7655 concentration-dependent MIC reduction was characterized by using a modified sigmoid maximum effect (E(max))-type model. Various dosing regimens of MK-7655 were simulated to achieve escalating T>MIC(i) values in the presence of a clinical dose of imipenem (500 mg every 6 h). The effectiveness of these dosing exposures was subsequently validated by using a hollow-fiber infection model (HFIM). An apparent trend in the bacterial response was observed in the HFIM with increasing T>MIC(i) values. In addition, different dosing regimens of MK-7655 achieving a similar T>MIC(i) (69%) resulted in comparable bacterial killing over 48 h. The proposed framework was reasonable in predicting the in vitro activity of a novel beta-lactamase inhibitor, and its utility warrants further investigations.

  19. Optimization of methazolamide-loaded solid lipid nanoparticles for ophthalmic delivery using Box-Behnken design.

    Science.gov (United States)

    Wang, Fengzhen; Chen, Li; Jiang, Sunmin; He, Jun; Zhang, Xiumei; Peng, Jin; Xu, Qunwei; Li, Rui

    2014-09-01

    The purpose of the present study was to optimize methazolamide (MTZ)-loaded solid lipid nanoparticles (SLNs) which were used as topical eye drops by evaluating the relationship between design factors and experimental data. A three factor, three-level Box-Behnken design (BBD) was used for the optimization procedure, choosing the amount of GMS, the amount of phospholipid, the concentration of surfactant as the independent variables. The chosen dependent variables were entrapment efficiency, dosage loading, and particle size. The generated polynomial equations and response surface plots were used to relate the dependent and independent variables. The optimal nanoparticles were formulated with 100 mg GMS, 150 mg phospholipid, and 1% Tween80 and PEG 400 (1:1, w/v). A new formulation was prepared according to these levels. The observed responses were close to the predicted values of the optimized formulation. The particle size was 197.8 ± 4.9 nm. The polydispersity index of particle size was 0.239 ± 0.01 and the zeta potential was 32.7 ± 2.6 mV. The entrapment efficiency and dosage loading were about 68.39% and 2.49%, respectively. Fourier transform infrared spectroscopy (FT-IR) study indicated that the drug was entrapped in nanoparticles. The optimized formulation showed a sustained release followed the Peppas model. MTZ-SLNs showed significant prolonged decreasing intraocular pressure effect comparing with MTZ solution in vivo pharmacodynamics studies. The results of acute eye irritation study indicated that MTZ-SLNs and AZOPT both had no eye irritation. Furthermore, the MTZ-SLNs were suitable to be stored at low temperature (4 °C).

  20. Real-time inverse high-dose-rate brachytherapy planning with catheter optimization by compressed sensing-inspired optimization strategies.

    Science.gov (United States)

    Guthier, C V; Aschenbrenner, K P; Müller, R; Polster, L; Cormack, R A; Hesser, J W

    2016-08-21

    This paper demonstrates that optimization strategies derived from the field of compressed sensing (CS) improve computational performance in inverse treatment planning (ITP) for high-dose-rate (HDR) brachytherapy. Following an approach applied to low-dose-rate brachytherapy, we developed a reformulation of the ITP problem with the same mathematical structure as standard CS problems. Two greedy methods, derived from hard thresholding and subspace pursuit are presented and their performance is compared to state-of-the-art ITP solvers. Applied to clinical prostate brachytherapy plans speed-up by a factor of 56-350 compared to state-of-the-art methods. Based on a Wilcoxon signed rank-test the novel method statistically significantly decreases the final objective function value (p  plans are either clinically equivalent or show a better performance with respect to dosimetric measures.

  1. GSO based optimization of steady state load shedding in power systems to mitigate blackout during generation contingencies

    Directory of Open Access Journals (Sweden)

    R. Mageshvaran

    2015-03-01

    Full Text Available Load shedding is considered as a last alternative to avoid the cascaded tripping and blackout in power systems during generation contingencies. It is essential to optimize the amount of load to be shed in order to prevent excessive load shedding. To minimize load shedding, this paper proposes the implementation of nature inspired optimization algorithm known as glowworm swarm optimization (GSO algorithm. The optimal solution of steady state load shedding is carried out by squaring the difference between the connected and supplied power (active and reactive. The proposed algorithm is tested on IEEE 14, 30, 57, 118 and Northern Regional Power Grid (NRPG-(India 246 bus test systems. The viability of the proposed method in terms of solution quality and convergence properties is compared with the conventional methods, namely, projected augmented Lagrangian method (PALM, gradient technique based on Kuhn–Tucker theorem (GTBKTT and second order gradient technique (SOGT.

  2. Comparison of the pro-postoperative analgesia of intraoperative dexmedetomidine with and without loading dose following general anesthesia

    Science.gov (United States)

    Fan, Wei; Yang, Haikou; Sun, Yong; Zhang, Jun; Li, Guangming; Zheng, Ying; Liu, Yi

    2017-01-01

    Abstract Intraoperative dexemdetomidine (DEX) with or without loading dose is well-established to improve postoperative pain control in patient-controlled analgesia (PCA). This study was designed to compare the pro-analgesia effect between the 2 in patients received general anesthesia. Seventy patients shceduced abdominal surgery under general anesthesia were randomly assigned into 3 groups which were maintained using propofol/remifentanil/Ringer solution (PRR), propofol/remifentanil/dexmedetomidine with (PRDw) or without (PRDo) a loading dose of dexmedetomidine before induction. PRDw/o patients displayed a greater Romsay sedation score measured immediately after surgery. When compared with PRR patients, those from the PRDw/o group had an increased time to first request of postoperative morphine and decreased 24 hours total morphine consumption. No significant difference was observed between patients from the PRDw and PRDo groups with respect to these parameters. The present study suggests that the administration of a DEX loading dose does not affect the pro-analgesic effect of intraoperative use of DEX on morphine-based PCA. PMID:28207529

  3. Topology optimization for elastic base under rectangular plate subjected to moving load

    Directory of Open Access Journals (Sweden)

    Jilavyan Samvel H.

    2015-09-01

    Full Text Available Distribution optimization of elastic material under elastic isotropic rectangular thin plate subjected to concentrated moving load is investigated in the present paper. The aim of optimization is to damp its vibrations in finite (fixed time. Accepting Kirchhoff hypothesis with respect to the plate and Winkler hypothesis with respect to the base, the mathematical model of the problem is constructed as two-dimensional bilinear equation, i.e. linear in state and control function. The maximal quantity of the base material is taken as optimality criterion to be minimized. The Fourier distributional transform and the Bubnov-Galerkin procedures are used to reduce the problem to integral equality type constraints. The explicit solution in terms of two- dimensional Heaviside‘s function is obtained, describing piecewise-continuous distribution of the material. The determination of the switching points is reduced to a problem of nonlinear programming. Data from numerical analysis are presented.

  4. Perform - A performance optimizing computer program for dynamic systems subject to transient loadings

    Science.gov (United States)

    Pilkey, W. D.; Wang, B. P.; Yoo, Y.; Clark, B.

    1973-01-01

    A description and applications of a computer capability for determining the ultimate optimal behavior of a dynamically loaded structural-mechanical system are presented. This capability provides characteristics of the theoretically best, or limiting, design concept according to response criteria dictated by design requirements. Equations of motion of the system in first or second order form include incompletely specified elements whose characteristics are determined in the optimization of one or more performance indices subject to the response criteria in the form of constraints. The system is subject to deterministic transient inputs, and the computer capability is designed to operate with a large linear programming on-the-shelf software package which performs the desired optimization. The report contains user-oriented program documentation in engineering, problem-oriented form. Applications cover a wide variety of dynamics problems including those associated with such diverse configurations as a missile-silo system, impacting freight cars, and an aircraft ride control system.

  5. Model-Based Individualized Treatment of Chemotherapeutics: Bayesian Population Modeling and Dose Optimization.

    Directory of Open Access Journals (Sweden)

    Devaraj Jayachandran

    Full Text Available 6-Mercaptopurine (6-MP is one of the key drugs in the treatment of many pediatric cancers, auto immune diseases and inflammatory bowel disease. 6-MP is a prodrug, converted to an active metabolite 6-thioguanine nucleotide (6-TGN through enzymatic reaction involving thiopurine methyltransferase (TPMT. Pharmacogenomic variation observed in the TPMT enzyme produces a significant variation in drug response among the patient population. Despite 6-MP's widespread use and observed variation in treatment response, efforts at quantitative optimization of dose regimens for individual patients are limited. In addition, research efforts devoted on pharmacogenomics to predict clinical responses are proving far from ideal. In this work, we present a Bayesian population modeling approach to develop a pharmacological model for 6-MP metabolism in humans. In the face of scarcity of data in clinical settings, a global sensitivity analysis based model reduction approach is used to minimize the parameter space. For accurate estimation of sensitive parameters, robust optimal experimental design based on D-optimality criteria was exploited. With the patient-specific model, a model predictive control algorithm is used to optimize the dose scheduling with the objective of maintaining the 6-TGN concentration within its therapeutic window. More importantly, for the first time, we show how the incorporation of information from different levels of biological chain-of response (i.e. gene expression-enzyme phenotype-drug phenotype plays a critical role in determining the uncertainty in predicting therapeutic target. The model and the control approach can be utilized in the clinical setting to individualize 6-MP dosing based on the patient's ability to metabolize the drug instead of the traditional standard-dose-for-all approach.

  6. Model-Based Individualized Treatment of Chemotherapeutics: Bayesian Population Modeling and Dose Optimization.

    Science.gov (United States)

    Jayachandran, Devaraj; Laínez-Aguirre, José; Rundell, Ann; Vik, Terry; Hannemann, Robert; Reklaitis, Gintaras; Ramkrishna, Doraiswami

    2015-01-01

    6-Mercaptopurine (6-MP) is one of the key drugs in the treatment of many pediatric cancers, auto immune diseases and inflammatory bowel disease. 6-MP is a prodrug, converted to an active metabolite 6-thioguanine nucleotide (6-TGN) through enzymatic reaction involving thiopurine methyltransferase (TPMT). Pharmacogenomic variation observed in the TPMT enzyme produces a significant variation in drug response among the patient population. Despite 6-MP's widespread use and observed variation in treatment response, efforts at quantitative optimization of dose regimens for individual patients are limited. In addition, research efforts devoted on pharmacogenomics to predict clinical responses are proving far from ideal. In this work, we present a Bayesian population modeling approach to develop a pharmacological model for 6-MP metabolism in humans. In the face of scarcity of data in clinical settings, a global sensitivity analysis based model reduction approach is used to minimize the parameter space. For accurate estimation of sensitive parameters, robust optimal experimental design based on D-optimality criteria was exploited. With the patient-specific model, a model predictive control algorithm is used to optimize the dose scheduling with the objective of maintaining the 6-TGN concentration within its therapeutic window. More importantly, for the first time, we show how the incorporation of information from different levels of biological chain-of response (i.e. gene expression-enzyme phenotype-drug phenotype) plays a critical role in determining the uncertainty in predicting therapeutic target. The model and the control approach can be utilized in the clinical setting to individualize 6-MP dosing based on the patient's ability to metabolize the drug instead of the traditional standard-dose-for-all approach.

  7. Optimization of dose radiation and image quality on computed tomography of thorax in adult women

    Energy Technology Data Exchange (ETDEWEB)

    Cruz Z, G. R.; Casian C, G. [Hospital Juarez de Mexico, Av. IPN No. 5160, 07760 Mexico D. F. (Mexico); Gaona, E.; Franco E, J. G.; Molina F, N., E-mail: gaen1310@correo.xoc.uam.mx [Universidad Autonoma Metropolitana, Unidad Xochimilco, Calz. del Hueso 1100, 04960 Mexico D. F. (Mexico)

    2015-10-15

    Full text: The objective of the study is the optimization of the dose (Dlp) and image quality in the exploration of adult women in studies of thorax with computed tomography (CT). The CT is a technique of exploration with high radiation doses to patients with an increase of the risk factors of developing cancer in the future, but X-rays are a very important medical diagnostic tool. We performed a retrospective survey of 50 female patients who had thorax tomography using the automatic protocol established by the manufacturer, a database of dose (Dlp), measures of patient A P and radiological parameters such as kV and m A was obtained. Subsequently, we carry out the prospective study with 30 patients with prescription of thorax tomography, scans were conducted with CT with reduced doses using manual techniques protocol of exploration while maintaining diagnostic image quality. The results show that the prospective study patients received doses lower than 30% on average. In general the dose patients were within the confidence interval of 95% of the levels of diagnostic reference (DRL) adopted by the European Community for CT and the most common value is 400 Dlp for thorax. Comparative image quality study was conducted using the protocol of the manufacturer and the manual protocol and image quality was diagnostic after dose reduction up to 30%. The reduction of radiation dose in female patients in studies of thorax CT helps to reduce risk factors of developing cancer later in life. A thorax tomography study includes the fibro-glandular tissue of the breast which is very sensitive to stochastic effects of radiation. (Author)

  8. The optimal succinylcholine dose for intubating emergency patients: retrospective comparative study

    Directory of Open Access Journals (Sweden)

    M. Magdy Hussien

    2011-07-01

    Full Text Available Background : Succinylcholine remains the drug of choice for satisfactory rapid-sequence tracheal intubation. It is not clear from the literature why the 1 mg/kg dose of succinylcholine has been traditionally used. The effective dose (ED95 of succinylcholine is less than 0.3 mg/kg. The dose of 1 mg/kg represents 3.5 to 4 times the ED95. Objectives : To compare the effect of the traditionally used 1 mg/kg of succinylcholine with lower doses of 0.6 mg/kg and 0.45 mg/kg on intubation condition regarding the onset time, duration of action, duration of abdominal fasciculation, and the intubation grading. Methods : This retrospective comparative study was carried into three groups of ASA III & IV (American Society of Anesthesiologist's Physical Status III and IV non-prepared emergency patients who were intubated at emergency department of Hamad General Hospital, Doha, Qatar during January 1st 2007 to August 31, 2010. The Institutional Research Board (IRB approval was obtained. This study was limited to 88 patients who received fentanyl 1 µg/kg followed by etomidate 0.3 mg/kg intravenously as induction agents and succinylcholine as a muscle relaxant agent in doses of 0.45 mg/kg, 0.6 mg/kg, or 1 mg/kg. Results : Increasing the succinylcholine dosage shortened the onset time, prolonged the duration of action, and prolonged the duration of abdominal fasciculation significantly (P<.001. Tracheal intubation was 100% successful in the three groups of patients. Conclusion : Succinylcholine dose of 0.45 mg/kg provides an optimal intubation condition in ASA III & IV emergency non-prepared patients. Duration of action of succinylcholine is dose dependent; reducing the dose allows a more rapid return of spontaneous respiration and airway reflexes.

  9. Dose optimization in simulated permanent interstitial implant of prostate brachytherapy; Otimizacao de dose em implantes intersticiais permanentes simulados de braquiterapia de prostata

    Energy Technology Data Exchange (ETDEWEB)

    Faria, Fernando Pereira de

    2006-07-01

    Any treatment of cancer that uses some modality of radiotherapy is planned before being executed. In general the goal in radiotherapy is to irradiate the target to be treated minimizing the incidence of radiation in healthy surrounding tissues. The planning differ among themselves according to the modality of radiotherapy, the type of cancer and where it is located. This work approaches the problem of dose optimization for the planning of prostate cancer treatment through the modality of low dose-rate brachytherapy with Iodine 125 or Palladium 103 seeds. An algorithm for dose calculation and optimization was constructed to find the seeds configuration that better fits the relevant clinical criteria such as as the tolerated dose by the urethra and rectum and the desired dose for prostate. The algorithm automatically finds this configuration from the prostate geometry established in two or three dimensions by using images of ultrasound, magnetic resonance or tomography and from the establishment of minimum restrictions to the positions of the seeds in the prostate and needles in a template. Six patterns of seeds distribution based on clinical criteria were suggested and tested in this work. Each one of these patterns generated a space of possible seeds configurations for the prostate tested by the dose calculation and optimization algorithm. The configurations that satisfied the clinical criteria were submitted to a test according to an optimization function suggested in this work. The configuration that produced maximum value for this function was considered the optimized one. (author)

  10. Optimizing the TLD-100 readout system for various radiotherapy beam doses using the Taguchi methodology

    Energy Technology Data Exchange (ETDEWEB)

    Chen, C.Y. [School of Medical Imaging Technology, Chung Shan Medical University, Taichung 402, Taiwan (China); Liu, K.C.; Chen, H.H. [Graduate Institute of Radiological Science, Central Taiwan University of Science and Technology, Takun, Taichung 406, Taiwan (China); Pan, L.K. [Graduate Institute of Radiological Science, Central Taiwan University of Science and Technology, Takun, Taichung 406, Taiwan (China)], E-mail: lkpan@ctust.edu.tw

    2010-03-15

    The TLD-100 readout system was optimized for various radiotherapy beam doses using the Taguchi method. The radiotherapy beam was produced by a Varian 21EX linear accelerator (LINAC) at 6 MV. The beam doses were 50, 100 and 150 cGy, and the measured data in each group were averaged from three TLD-100 chips. A total of nine combinations of four parameters were arranged, in the manner suggested by Taguchi. The four parameters were defined as initial temperature, heating rate, preheat time and maximum set temperature of the readout system during TLD reading. The loss function {eta} adopted herein was specifically defined to satisfy the requirements of both sharp linearity and good reproducibility of the TLD reading at various radiotherapy beam doses. The optimized values were: (1) 50 deg. C for initial temperature, (2) 3 deg. C/s for heating rate, (3) 5 min for the TLD preheat time and (4) 250 deg. C for the maximum temperature for TLD reading. Additionally, the parameters that dominated the TLD readout were: (1) initial temperature, (2) heating rate and (4) maximum temperature setting for TLD reading; and the minor parameter was (3) TLD preheat time before reading. The interactions among the dominant parameters were also studied: no significant cross interaction occurred between initial temperature and heating rate or between initial temperature and maximum temperature. However, a complex cross-interaction existed between optimal heating rate and maximum temperature.

  11. Cancer risk assessment: Optimizing human health through linear dose-response models.

    Science.gov (United States)

    Calabrese, Edward J; Shamoun, Dima Yazji; Hanekamp, Jaap C

    2015-07-01

    This paper proposes that generic cancer risk assessments be based on the integration of the Linear Non-Threshold (LNT) and hormetic dose-responses since optimal hormetic beneficial responses are estimated to occur at the dose associated with a 10(-4) risk level based on the use of a LNT model as applied to animal cancer studies. The adoption of the 10(-4) risk estimate provides a theoretical and practical integration of two competing risk assessment models whose predictions cannot be validated in human population studies or with standard chronic animal bioassay data. This model-integration reveals both substantial protection of the population from cancer effects (i.e. functional utility of the LNT model) while offering the possibility of significant reductions in cancer incidence should the hormetic dose-response model predictions be correct. The dose yielding the 10(-4) cancer risk therefore yields the optimized toxicologically based "regulatory sweet spot". Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. SU-E-T-453: Optimization of Dose Gradient for Gamma Knife Radiosurgery.

    Science.gov (United States)

    Sheth, N; Chen, Y; Yang, J

    2012-06-01

    The goals of stereotactic radiosurgery (SRS) are the ablation of target tissue and sparing of critical normal tissue. We develop tools to aid in the selection of collimation and prescription (Rx) isodose line to optimize the dose gradient for single isocenter intracranial stereotactic radiosurgery (SRS) with GammaKnife 4C utilizing the updated physics data in GammaPlan v10.1. Single isocenter intracranial SRS plans were created to treat the center of a solid water anthropomorphism head phantom for each GammaKnife collimator (4 mm, 8 mm, 14 mm, and 18 mm). The dose gradient, defined as the difference of effective radii of spheres equal to half and full Rx volumes, and Rx treatment volume was analyzed for isodoses from 99% to 20% of Rx. The dosimetric data on Rx volume and dose gradient vs. Rx isodose for each collimator was compiled into an easy to read nomogram as well as plotted graphically. The 4, 8, 14, and 18 mm collimators have the sharpest dose gradient at the 64%, 70%, 76%, and 77% Rx isodose lines, respectively. This corresponds to treating 4.77 mm, 8.86 mm, 14.78 mm, and 18.77 mm diameter targets with dose gradients radii of 1.06 mm, 1.63 mm, 2.54 mm, and 3.17 mm, respectively. We analyzed the dosimetric data for the most recent version of GammaPlan treatment planning software to develop tools that when applied clinically will aid in the selection of a collimator and Rx isodose line for optimal dose gradient and target coverage for single isocenter intracranial SRS with GammaKnife 4C. © 2012 American Association of Physicists in Medicine.

  13. Preparation, optimization, and in vitro simulated inhalation delivery of carvedilol nanoparticles loaded on a coarse carrier intended for pulmonary administration

    Directory of Open Access Journals (Sweden)

    Abdelbary AA

    2015-10-01

    Full Text Available Aly A Abdelbary,1 Abdulaziz M Al-mahallawi,1 Mohamed E Abdelrahim,2 Ahmed MA Ali3,4 1Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Cairo University, Cairo, 2Department of Clinical Pharmacy, 3Department of Pharmaceutics, Faculty of Pharmacy, Beni Suef University, Beni Suef, Egypt; 4Department of Pharmaceutics, Faculty of Pharmacy, Taif University, Taif, Saudi Arabia Abstract: Carvedilol (CAR is a potent antihypertensive drug but has poor oral bioavailability (24%. A nanosuspension suitable for pulmonary delivery to enhance bioavailability and bypass first-pass metabolism of CAR could be advantageous. Accordingly, the aim of this work was to prepare CAR nanosuspensions and to use artificial neural networks associated with genetic algorithm to model and optimize the formulations. The optimized nanosuspension was lyophilized to obtain dry powder suitable for inhalation. However, respirable particles must have a diameter of 1–5 µm in order to deposit in the lungs. Hence, mannitol was used during lyophilization for cryoprotection and to act as a coarse carrier for nanoparticles in order to deliver them into their desired destination. The bottom-up technique was adopted for nanosuspension formulation using Pluronic stabilizers (F127, F68, and P123 combined with sodium deoxycholate at 1:1 weight ratio, at three levels with two drug loads and two aqueous to organic phase volume ratios. The drug crystallinity was studied using differential scanning calorimetry and powder X-ray diffractometry. The in vitro emitted doses of CAR were evaluated using a dry powder inhaler sampling apparatus and the aerodynamic characteristics were evaluated using an Andersen MKII cascade impactor. The artificial neural networks results showed that Pluronic F127 was the optimum stabilizer based on the desired particle size, polydispersity index, and zeta potential. Results of differential scanning calorimetry combined with powder X

  14. Radiation Load Optimization in the Final Focus System of FCC-hh

    CERN Document Server

    Martin, Roman; Cerutti, Francesco; Tomás, Rogelio

    2016-01-01

    With a center-of-mass energy of up to 100 TeV, FCC-hh will produce highly energetic collision debris at the Interaction Point (IP). Protecting the final focus quadrupoles from this radiation is challenging, since the required amount of shielding placed inside the magnets will reduce the free aperture, thereby limiting the β^{*} reach and luminosity. Hence, radiation mitigation strategies that make best use of the available aperture are required. In this paper, we study the possibility to split the first quadrupole Q1 into two quadrupoles with individual apertures, in order to distribute the radiation load more evenly and reduce the peak dose.

  15. Comparison of linear and nonlinear programming approaches for "worst case dose" and "minmax" robust optimization of intensity-modulated proton therapy dose distributions.

    Science.gov (United States)

    Zaghian, Maryam; Cao, Wenhua; Liu, Wei; Kardar, Laleh; Randeniya, Sharmalee; Mohan, Radhe; Lim, Gino

    2017-03-01

    Robust optimization of intensity-modulated proton therapy (IMPT) takes uncertainties into account during spot weight optimization and leads to dose distributions that are resilient to uncertainties. Previous studies demonstrated benefits of linear programming (LP) for IMPT in terms of delivery efficiency by considerably reducing the number of spots required for the same quality of plans. However, a reduction in the number of spots may lead to loss of robustness. The purpose of this study was to evaluate and compare the performance in terms of plan quality and robustness of two robust optimization approaches using LP and nonlinear programming (NLP) models. The so-called "worst case dose" and "minmax" robust optimization approaches and conventional planning target volume (PTV)-based optimization approach were applied to designing IMPT plans for five patients: two with prostate cancer, one with skull-based cancer, and two with head and neck cancer. For each approach, both LP and NLP models were used. Thus, for each case, six sets of IMPT plans were generated and assessed: LP-PTV-based, NLP-PTV-based, LP-worst case dose, NLP-worst case dose, LP-minmax, and NLP-minmax. The four robust optimization methods behaved differently from patient to patient, and no method emerged as superior to the others in terms of nominal plan quality and robustness against uncertainties. The plans generated using LP-based robust optimization were more robust regarding patient setup and range uncertainties than were those generated using NLP-based robust optimization for the prostate cancer patients. However, the robustness of plans generated using NLP-based methods was superior for the skull-based and head and neck cancer patients. Overall, LP-based methods were suitable for the less challenging cancer cases in which all uncertainty scenarios were able to satisfy tight dose constraints, while NLP performed better in more difficult cases in which most uncertainty scenarios were hard to meet

  16. Optimizing ribavirin dose in HIV/hepatitis C (HCV co-infected individuals treated for HCV

    Directory of Open Access Journals (Sweden)

    J Farley

    2012-11-01

    Full Text Available Hepatitis C (HCV and HIV share common transmission pathways and the acquisition of both viruses are relatively common. Concurrent treatment for HCV with highly active anti-retroviral therapy (HAART should be considered in HIV co-infected individuals to decrease the progression of liver damage. Adverse effects and less satisfactory treatment outcomes are often concerns when treating co-infected individuals. Although, direct acting antivirals (DAAs may increase SVR, they may not be possible because of drug-drug interactions. he objective of this study is to investigate the difference in response rates of HCV treatment in HIV co-infected inmates with varying doses of ribavirin. Retrospective medical chart reviews of 52 HCV/HIV co-infected inmates who underwent HCV therapy between 2003 and 2010. All received standard doses of pegylated interferon alpha 2a or 2b and 800–1600 mg of ribavirin depending on weight. The recommended dosage for genotypes 2 and 3 is 800 mg/day. For other genotypes, if weight is<75 kg, the recommended ribavirin dose is 1000 mg/day or 1200 mg/day if>75 kg. Efficacy was defined as attaining sustained virological response (SVR six months post treatment. Univariate analyses was performed using SPSS-18; Chi-square test with p-value<0.05 was defined significant. 52 co-infected (3 females & 49 males were identified. Mean age was 40±7 years. Caucasians accounted for 84.6%; First Nations for 13.5% and Asians 1.9%. 36 were concurrently on HAART. The genotype distribution was: geno 1, 66.0%; geno 2, 7.5%; geno 3, 26.4%. SVR by ribavirin dosage ratio (actual dosage/recommended dosage:=1.0; 41.2% (14/34,>1.0; 58.8% (20/34. Doses greater than 1.5 times were associated with higher adverse events and lower SVR. Suboptimal doses of weight-based ribavirin may be contributing to a lower treatment response in HCV/HIV co-infectants. In our experience, the optimal dose of ribavirin is between 1 and 1.2 times the current recommended dose. We

  17. Tackling optimization challenges in industrial load control and full-duplex radios

    Science.gov (United States)

    Gholian, Armen

    In price-based demand response programs in smart grid, utilities set the price in accordance with the grid operating conditions and consumers respond to price signals by conducting optimal load control to minimize their energy expenditure while satisfying their energy needs. Industrial sector consumes a large portion of world electricity and addressing optimal load control of energy-intensive industrial complexes, such as steel industry and oil-refinery, is of practical importance. Formulating a general industrial complex and addressing issues in optimal industrial load control in smart grid is the focus of the second part of this dissertation. Several industrial load details are considered in the proposed formulation, including those that do not appear in residential or commercial load control problems. Operation under different smart pricing scenarios, namely, day-ahead pricing, time-of-use pricing, peak pricing, inclining block rates, and critical peak pricing are considered. The use of behind-the-meter renewable generation and energy storage is also considered. The formulated optimization problem is originally nonlinear and nonconvex and thus hard to solve. However, it is then reformulated into a tractable linear mixed-integer program. The performance of the design is assessed through various simulations for an oil refinery and a steel mini-mill. In the third part of this dissertation, a novel all-analog RF interference canceler is proposed. Radio self-interference cancellation (SIC) is the fundamental enabler for full-duplex radios. While SIC methods based on baseband digital signal processing and/or beamforming are inadequate, an all-analog method is useful to drastically reduce the self-interference as the first stage of SIC. It is shown that a uniform architecture with uniformly distributed RF attenuators has a performance highly dependent on the carrier frequency. It is also shown that a new architecture with the attenuators distributed in a clustered

  18. SU-E-T-09: A Clinical Implementation and Optimized Dosimetry Study of Freiberg Flap Skin Surface Treatment in High Dose Rate Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Syh, J; Syh, J; Patel, B; Wu, H; Durci, M [Willis-Knighton Medical Center, Shreveport, LA (United States)

    2015-06-15

    Purpose: This case study was designated to confirm the optimized plan was used to treat skin surface of left leg in three stages. 1. To evaluate dose distribution and plan quality by alternating of the source loading catheters pattern in flexible Freiberg Flap skin surface (FFSS) applicator. 2. To investigate any impact on Dose Volume Histogram (DVH) of large superficial surface target volume coverage. 3. To compare the dose distribution if it was treated with electron beam. Methods: The Freiburg Flap is a flexible mesh style surface mold for skin radiation or intraoperative surface treatments. The Freiburg Flap consists of multiple spheres that are attached to each other, holding and guiding up to 18 treatment catheters. The Freiburg Flap also ensures a constant distance of 5mm from the treatment catheter to the surface. Three treatment trials with individual planning optimization were employed: 18 channels, 9 channels of FF and 6 MeV electron beam. The comparisons were highlighted in target coverage, dose conformity and dose sparing of surrounding tissues. Results: The first 18 channels brachytherapy plan was generated with 18 catheters inside the skin-wrapped up flap (Figure 1A). A second 9 catheters plan was generated associated with the same calculation points which were assigned to match prescription for target coverage as 18 catheters plan (Figure 1B). The optimized inverse plan was employed to reduce the dose to adjacent structures such as tibia or fibula. The comparison of DVH’s was depicted on Figure 2. External beam of electron RT plan was depicted in Figure 3. Overcall comparisons among these three were illustrated in Conclusion: The 9-channel Freiburg flap flexible skin applicator offers a reasonably acceptable plan without compromising the coverage. Electron beam was discouraged to use to treat curved skin surface because of low target coverage and high dose in adjacent tissues.

  19. Optimal Scheduling Method of Controllable Loads in DC Smart Apartment Building

    Science.gov (United States)

    Shimoji, Tsubasa; Tahara, Hayato; Matayoshi, Hidehito; Yona, Atsushi; Senjyu, Tomonobu

    2015-12-01

    From the perspective of global warming suppression and the depletion of energy resources, renewable energies, such as the solar collector (SC) and photovoltaic generation (PV), have been gaining attention in worldwide. Houses or buildings with PV and heat pumps (HPs) are recently being used in residential areas widely due to the time of use (TOU) electricity pricing scheme which is essentially inexpensive during middle-night and expensive during day-time. If fixed batteries and electric vehicles (EVs) can be introduced in the premises, the electricity cost would be even more reduced. While, if the occupants arbitrarily use these controllable loads respectively, power demand in residential buildings may fluctuate in the future. Thus, an optimal operation of controllable loads such as HPs, batteries and EV should be scheduled in the buildings in order to prevent power flow from fluctuating rapidly. This paper proposes an optimal scheduling method of controllable loads, and the purpose is not only the minimization of electricity cost for the consumers, but also suppression of fluctuation of power flow on the power supply side. Furthermore, a novel electricity pricing scheme is also suggested in this paper.

  20. Advanced and flexible genetic algorithms for BWR fuel loading pattern optimization

    Energy Technology Data Exchange (ETDEWEB)

    Martin-del-Campo, Cecilia [Departamento de Sistemas Energeticos, Facultad de Ingenieria, Universidad Nacional Autonoma de Mexico, Paseo Cuauhnahuac 8532, Jiutepec, Mor., 62550 (Mexico)], E-mail: cmcm@fi-b.unam.mx; Palomera-Perez, Miguel-Angel [Instituto de Investigaciones en Matematicas Aplicadas y Sistemas, Universidad Nacional Autonoma de Mexico, Circuito Escolar, Ciudad Universitaria, 04510 DF (Mexico)], E-mail: mapp@uxmcc2.iimas.unam.mx; Francois, Juan-Luis [Departamento de Sistemas Energeticos, Facultad de Ingenieria, Universidad Nacional Autonoma de Mexico, Paseo Cuauhnahuac 8532, Jiutepec, Mor., 62550 (Mexico)], E-mail: jlfl@fi-b.unam.mx

    2009-10-15

    This work proposes advances in the implementation of a flexible genetic algorithm (GA) for fuel loading pattern optimization for Boiling Water Reactors (BWRs). In order to avoid specific implementations of genetic operators and to obtain a more flexible treatment, a binary representation of the solution was implemented; this representation had to take into account that a little change in the genotype must correspond to a little change in the phenotype. An identifier number is assigned to each assembly by means of a Gray Code of 7 bits and the solution (the loading pattern) is represented by a binary chain of 777 bits of length. Another important contribution is the use of a Fitness Function which includes a Heuristic Function and an Objective Function. The Heuristic Function which is defined to give flexibility on the application of a set of positioning rules based on knowledge, and the Objective Function that contains all the parameters which qualify the neutronic and thermal hydraulic performances of each loading pattern. Experimental results illustrating the effectiveness and flexibility of this optimization algorithm are presented and discussed.

  1. Improved dose-volume histogram estimates for radiopharmaceutical therapy by optimizing quantitative SPECT reconstruction parameters

    Science.gov (United States)

    Cheng, Lishui; Hobbs, Robert F.; Segars, Paul W.; Sgouros, George; Frey, Eric C.

    2013-06-01

    In radiopharmaceutical therapy, an understanding of the dose distribution in normal and target tissues is important for optimizing treatment. Three-dimensional (3D) dosimetry takes into account patient anatomy and the nonuniform uptake of radiopharmaceuticals in tissues. Dose-volume histograms (DVHs) provide a useful summary representation of the 3D dose distribution and have been widely used for external beam treatment planning. Reliable 3D dosimetry requires an accurate 3D radioactivity distribution as the input. However, activity distribution estimates from SPECT are corrupted by noise and partial volume effects (PVEs). In this work, we systematically investigated OS-EM based quantitative SPECT (QSPECT) image reconstruction in terms of its effect on DVHs estimates. A modified 3D NURBS-based Cardiac-Torso (NCAT) phantom that incorporated a non-uniform kidney model and clinically realistic organ activities and biokinetics was used. Projections were generated using a Monte Carlo (MC) simulation; noise effects were studied using 50 noise realizations with clinical count levels. Activity images were reconstructed using QSPECT with compensation for attenuation, scatter and collimator-detector response (CDR). Dose rate distributions were estimated by convolution of the activity image with a voxel S kernel. Cumulative DVHs were calculated from the phantom and QSPECT images and compared both qualitatively and quantitatively. We found that noise, PVEs, and ringing artifacts due to CDR compensation all degraded histogram estimates. Low-pass filtering and early termination of the iterative process were needed to reduce the effects of noise and ringing artifacts on DVHs, but resulted in increased degradations due to PVEs. Large objects with few features, such as the liver, had more accurate histogram estimates and required fewer iterations and more smoothing for optimal results. Smaller objects with fine details, such as the kidneys, required more iterations and less

  2. Optimal matching of 3D film-measured and planned doses for intensity-modulated radiation therapy quality assurance.

    Science.gov (United States)

    Shin, Dongho; Yoon, Myonggeun; Park, Sung Yong; Park, Dong Hyun; Lee, Se Byeong; Kim, Dae Yong; Cho, Kwan Ho

    2007-01-01

    Intensity-modulated radiation therapy (IMRT) is one of the most complex applications of radiotherapy that requires patient-specific quality assurance (QA). Here, we describe a novel method of 3-dimensional (3D) dose-verification using 12 acrylic slabs in a 3D phantom (30 x 30 x 12 cm(3)) with extended dose rate (EDR2) films, which is both faster than conventionally used methods, and clinically useful. With custom-written software modules written in Microsoft Excel Visual Basic Application, the measured and planned dose distributions for the axial, coronal, and sagittal planes were superimposed by matching their origins, and the point doses were compared at all matched positions. Then, an optimization algorithm was used to correct the detected setup errors. The results show that this optimization method significantly reduces the average maximum dose difference by 7.73% and the number of points showing dose differences of more than 5% by 8.82% relative to the dose differences without an optimization. Our results indicate that the dose difference was significantly decreased with optimization and this optimization method is statistically reliable and effective. The results of 3D optimization are discussed in terms of various patient-specific QA data obtained from statistical analyses.

  3. A non-optimized follower load path may cause considerable intervertebral rotations.

    Science.gov (United States)

    Dreischarf, Marcel; Zander, Thomas; Bergmann, Georg; Rohlmann, Antonius

    2010-09-17

    Osseoligamentous spinal specimens buckle under even a small vertical compressive force. To allow higher axial forces, a compressive follower load (FL) was suggested previously that approximates the curvature of the spine without inducing intervertebral rotation in both the frontal and the sagittal planes. In in vitro experiments and finite element analyses, the location of the FL path is subjected to estimation by the investigator. Such non-optimized FLs may induce bending and so far it is still unknown how this affects the results of the study and their comparability. A symmetrical finite element model of the lumbar spine was employed to simulate upright standing while applying a follower load. In analogy to in vitro experiments, the path of this FL was estimated seven times by different members of our institute's spine group. Additionally, an optimized FL path was determined and additional moments of +/-7.5Nm were applied to simulate flexion and extension. Application of the optimized 500N compressive FL causes only a marginal alteration of the curvature (cardan angle L1-S1 in sagittal plane <0.25 degrees). An individual estimation of the FL path, however, results in flexions of up to 10.0 degrees or extensions of up to 12.3 degrees. The resulting angles for the different non-optimized FL paths depend on the magnitude of the bending moment applied and whether a differential or an absolute measurement is taken. A preceding optimization of the location of the FL path would increase the comparability of different studies.

  4. Energy Coordinative Optimization of Wind-Storage-Load Microgrids Based on Short-Term Prediction

    Directory of Open Access Journals (Sweden)

    Changbin Hu

    2015-02-01

    Full Text Available According to the topological structure of wind-storage-load complementation microgrids, this paper proposes a method for energy coordinative optimization which focuses on improvement of the economic benefits of microgrids in the prediction framework. First of all, the external characteristic mathematical model of distributed generation (DG units including wind turbines and storage batteries are established according to the requirements of the actual constraints. Meanwhile, using the minimum consumption costs from the external grid as the objective function, a grey prediction model with residual modification is introduced to output the predictive wind turbine power and load at specific periods. Second, based on the basic framework of receding horizon optimization, an intelligent genetic algorithm (GA is applied to figure out the optimum solution in the predictive horizon for the complex non-linear coordination control model of microgrids. The optimum results of the GA are compared with the receding solution of mixed integer linear programming (MILP. The obtained results show that the method is a viable approach for energy coordinative optimization of microgrid systems for energy flow and reasonable schedule. The effectiveness and feasibility of the proposed method is verified by examples.

  5. Dynamic Response and Optimal Design of Curved Metallic Sandwich Panels under Blast Loading

    Directory of Open Access Journals (Sweden)

    Chang Qi

    2014-01-01

    Full Text Available It is important to understand the effect of curvature on the blast response of curved structures so as to seek the optimal configurations of such structures with improved blast resistance. In this study, the dynamic response and protective performance of a type of curved metallic sandwich panel subjected to air blast loading were examined using LS-DYNA. The numerical methods were validated using experimental data in the literature. The curved panel consisted of an aluminum alloy outer face and a rolled homogeneous armour (RHA steel inner face in addition to a closed-cell aluminum foam core. The results showed that the configuration of a “soft” outer face and a “hard” inner face worked well for the curved sandwich panel against air blast loading in terms of maximum deflection (MaxD and energy absorption. The panel curvature was found to have a monotonic effect on the specific energy absorption (SEA and a nonmonotonic effect on the MaxD of the panel. Based on artificial neural network (ANN metamodels, multiobjective optimization designs of the panel were carried out. The optimization results revealed the trade-off relationships between the blast-resistant and the lightweight objectives and showed the great use of Pareto front in such design circumstances.

  6. Dynamic response and optimal design of curved metallic sandwich panels under blast loading.

    Science.gov (United States)

    Qi, Chang; Yang, Shu; Yang, Li-Jun; Han, Shou-Hong; Lu, Zhen-Hua

    2014-01-01

    It is important to understand the effect of curvature on the blast response of curved structures so as to seek the optimal configurations of such structures with improved blast resistance. In this study, the dynamic response and protective performance of a type of curved metallic sandwich panel subjected to air blast loading were examined using LS-DYNA. The numerical methods were validated using experimental data in the literature. The curved panel consisted of an aluminum alloy outer face and a rolled homogeneous armour (RHA) steel inner face in addition to a closed-cell aluminum foam core. The results showed that the configuration of a "soft" outer face and a "hard" inner face worked well for the curved sandwich panel against air blast loading in terms of maximum deflection (MaxD) and energy absorption. The panel curvature was found to have a monotonic effect on the specific energy absorption (SEA) and a nonmonotonic effect on the MaxD of the panel. Based on artificial neural network (ANN) metamodels, multiobjective optimization designs of the panel were carried out. The optimization results revealed the trade-off relationships between the blast-resistant and the lightweight objectives and showed the great use of Pareto front in such design circumstances.

  7. Optimizing the Design of Connecting Rod under Static and Fatigue Loading

    Directory of Open Access Journals (Sweden)

    Om Parkash

    2013-06-01

    Full Text Available The main objective of this work is to re-optimize theexisting design of connecting rod of universal tractor (U650 bychanging some of the design variables. The existing designperforms modelling and evaluates critical regions in theconnecting rod under fatigue loading. In the present work, themodel is developed, analyzed and designed using CATIA 19,PRO-E and ANSYS workbench v12. Optimization of connectingrod is done under same boundary and loading conditions forvariation in the few stress and fatigue parameters i.e. stresses,weight, life, damage, bi-axiality indication and safety factor. Theallowable numbers of cycles under fully reversed fatigue loadingare increased and assumed up to a maximum limit of 109 cycles.Stress concentration coefficient is varied to obtain the maximumcycles condition. The critical regions under both static andfatigue analysis are identified and improved. The connecting rodis modelled and optimized for the reduced weight, improved lifeand manufacturability. The results obtained from performedanalysis can be used to modify the design of existing connectingrod, so that better performance i.e. reduced inertia, fatigue lifeand manufacturability can be obtained under varying static andfatigue conditions.

  8. Optimal dose and volume for postoperative radiotherapy in brain oligometastases from lung cancer: a retrospective study

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Seung Yeun; Kim, Hye Ryun; Cho, Byoung Chul; Lee, Chang Geol; Suh, Chang Ok [Yonsei Cancer Center, Yonsei University College of Medicine, Seoul (Korea, Republic of); Chang, Jong Hee [Dept. of Neurosurgery, Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2017-06-15

    To evaluate intracranial control after surgical resection according to the adjuvant treatment received in order to assess the optimal radiotherapy (RT) dose and volume. Between 2003 and 2015, a total of 53 patients with brain oligometastases from non-small cell lung cancer (NSCLC) underwent metastasectomy. The patients were divided into three groups according to the adjuvant treatment received: whole brain radiotherapy (WBRT) ± boost (WBRT ± boost group, n = 26), local RT/Gamma Knife surgery (local RT group, n = 14), and the observation group (n = 13). The most commonly used dose schedule was WBRT (25 Gy in 10 fractions, equivalent dose in 2 Gy fractions [EQD2] 26.04 Gy) with tumor bed boost (15 Gy in 5 fractions, EQD2 16.25 Gy). The WBRT ± boost group showed the lowest 1-year intracranial recurrence rate of 30.4%, followed by the local RT and observation groups, at 66.7%, and 76.9%, respectively (p = 0.006). In the WBRT ± boost group, there was no significant increase in the 1-year new site recurrence rate of patients receiving a lower dose of WBRT (EQD2) <27 Gy compared to that in patients receiving a higher WBRT dose (p = 0.553). The 1-year initial tumor site recurrence rate was lower in patients receiving tumor bed dose (EQD2) of ≥42.3 Gy compared to those receiving <42.3 Gy, although the difference was not significant (p = 0.347). Adding WBRT after resection of brain oligometastases from NSCLC seems to enhance intracranial control. Furthermore, combining lower-dose WBRT with a tumor bed boost may be an attractive option.

  9. WE-B-304-00: Point/Counterpoint: Biological Dose Optimization

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2015-06-15

    The ultimate goal of radiotherapy treatment planning is to find a treatment that will yield a high tumor control probability (TCP) with an acceptable normal tissue complication probability (NTCP). Yet most treatment planning today is not based upon optimization of TCPs and NTCPs, but rather upon meeting physical dose and volume constraints defined by the planner. It has been suggested that treatment planning evaluation and optimization would be more effective if they were biologically and not dose/volume based, and this is the claim debated in this month’s Point/Counterpoint. After a brief overview of biologically and DVH based treatment planning by the Moderator Colin Orton, Joseph Deasy (for biological planning) and Charles Mayo (against biological planning) will begin the debate. Some of the arguments in support of biological planning include: this will result in more effective dose distributions for many patients DVH-based measures of plan quality are known to have little predictive value there is little evidence that either D95 or D98 of the PTV is a good predictor of tumor control sufficient validated outcome prediction models are now becoming available and should be used to drive planning and optimization Some of the arguments against biological planning include: several decades of experience with DVH-based planning should not be discarded we do not know enough about the reliability and errors associated with biological models the radiotherapy community in general has little direct experience with side by side comparisons of DVH vs biological metrics and outcomes it is unlikely that a clinician would accept extremely cold regions in a CTV or hot regions in a PTV, despite having acceptable TCP values Learning Objectives: To understand dose/volume based treatment planning and its potential limitations To understand biological metrics such as EUD, TCP, and NTCP To understand biologically based treatment planning and its potential limitations.

  10. Formulation and characterization of tramadol-loaded IPN microgels of alginate and gelatin: Optimization using response surface methodology

    National Research Council Canada - National Science Library

    Kumar, Pradeep; Singh, Inderbir

    2010-01-01

    Tramadol-loaded interpenetrating polymer network (IPN) alginate-gelatin (AG) microgels (MG) were prepared by the chemical cross-linking technique with glutaraldehyde as cross-linking agent and were optimized using response surfaces...

  11. Towards optimization of nuclear waste glass: Constraints, property models, and waste loading

    Energy Technology Data Exchange (ETDEWEB)

    Hrma, P.

    1994-04-01

    Vitrification of both low- and high-level wastes from 177 tanks at Hanford poses a great challenge to glass makers, whose task is to formulate a system of glasses that are acceptable to the federal repository for disposal. The enormous quantity of the waste requires a glass product of the lowest possible volume. The incomplete knowledge of waste composition, its variability, and lack of an appropriate vitrification technology further complicates this difficult task. A simple relationship between the waste loading and the waste glass volume is presented and applied to the predominantly refractory (usually high-activity) and predominantly alkaline (usually low-activity) waste types. Three factors that limit waste loading are discussed, namely product acceptability, melter processing, and model validity. Glass formulation and optimization problems are identified and a broader approach to uncertainties is suggested.

  12. Optimal Control with Complete Load-Decoupled Design for the Buck DC-DC Switching Converter

    Institute of Scientific and Technical Information of China (English)

    Fei-Hu; Hsieh; Yau-Tarng; Juang

    2002-01-01

    This paper describes a new controller design procedure and turning method for the buck PWM DCDCswitching converter taking into consideration the equivalent series resistance of components. First, the linearoptimal feedback is designed by the LQR approach. Then the designed control law is implemented by aphase-lag lead controller incorporated with a complete load-decoupled PD compensator. The phase-lag lead controlleris tuned to achieve the optimal design based on the output error voltage directly, instead of using an estimator.With the proposed PD compensator, the converter is robust with respect to the load changes and parameterperturbations. We also provide the conditions for the robust stability assurance of the closed-loop system.

  13. Model predictive load following control for APR+ reactors through discrete control rod speed optimization

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Hwan; Kim, Ju Hyun; Park, Sun Ho; Yoo, Kwae Hwan; Kim, Dae Seop; Na, Man Gyun [Chosun Univ., Gwanggu (Korea, Republic of)

    2012-10-15

    Until now, nuclear power has been only used for the base load power operation. However, current nuclear power plants are recognized as the most reasonable energy source. As a result, the proportion of nuclear power has being grown increasingly. Therefore, load following operation of a nuclear power plant should be an essential option. Most of the existing nuclear power plants perform reactor operation by varying the boron concentration in the coolant. But it is hard to respond quickly to demands for the power changes. In case of using the control rods, reactivity control is easy, but axial power distribution control is very hard because it has very complex and nonlinear dynamic characteristics. In this study, we have introduced a Model Predictive Control (MPC) method to control the average coolant temperature and Axial Shape Index (ASI) automatically at the same time, and we have improved the performance of controller by applying the Genetic Algorithm (GA) to optimize the control rod movement.

  14. Performance evaluation of PSO and GA in PWR core loading pattern optimization

    Energy Technology Data Exchange (ETDEWEB)

    Khoshahval, F., E-mail: f_khoshahval@sbu.ac.i [Engineering Department, Shahid Beheshti University, G.C., P.O. Box 1983963113, Velenjak, Tehran (Iran, Islamic Republic of); Minuchehr, H. [Engineering Department, Shahid Beheshti University, G.C., P.O. Box 1983963113, Velenjak, Tehran (Iran, Islamic Republic of); Zolfaghari, A., E-mail: a-zolfaghari@sbu.ac.i [Engineering Department, Shahid Beheshti University, G.C., P.O. Box 1983963113, Velenjak, Tehran (Iran, Islamic Republic of)

    2011-03-15

    Research highlights: The performance of both GA and PSO methods in optimizing of a PWR core are adequate. It seems GA arrives to its final parameter value in a fewer generation than the PSO. The computation time for GA is higher than PSO. The GA-2 and PSO-CFA algorithms perform better in comparison to GA-1 and PSO-IWA. - Abstract: The efficient operation and fuel management of PWRs are of utmost importance. Recently, genetic algorithm (GA) and particle swarm optimization (PSO) techniques have attracted considerable attention among various modern heuristic optimization techniques. GA is a powerful optimization technique, based upon the principles of natural selection and species evolution. GA is finding popularity as design tools because of its versatility, intuitiveness and ability to solve highly non-linear, mixed integer optimization problems. PSO refers to a relatively new family of algorithms and is mainly inspired by social behavior patterns of organisms that live within large group. This study addresses the application and performance comparison of PSO and GA optimization methods for nuclear fuel loading pattern problem. Flattening of power inside the reactor core of Bushehr nuclear power plant (WWER-1000 type) is chosen as an objective function to prove the validity of algorithms. In addition the performance of both optimization techniques in terms of convergence rate and computational time is compared. It is found that, from an evolutionary point of view, the performance of both GA and PSO is quite adequate. But, GA seems to arrive at its final parameter value in a fewer generations than the PSO. It is also noticed that, the computation time for implemented GA in this work is too high in comparison to PSO.

  15. Experimental design and optimization of raloxifene hydrochloride loaded nanotransfersomes for transdermal application

    Directory of Open Access Journals (Sweden)

    Mahmood S

    2014-09-01

    Full Text Available Syed Mahmood, Muhammad Taher, Uttam Kumar Mandal Department of Pharmaceutical Technology, Kulliyyah of Pharmacy, International Islamic University Malaysia (IIUM, Pahang Darul Makmur, Malaysia Abstract: Raloxifene hydrochloride, a highly effective drug for the treatment of invasive breast cancer and osteoporosis in post-menopausal women, shows poor oral bioavailability of 2%. The aim of this study was to develop, statistically optimize, and characterize raloxifene hydrochloride-loaded transfersomes for transdermal delivery, in order to overcome the poor bioavailability issue with the drug. A response surface methodology experimental design was applied for the optimization of transfersomes, using Box-Behnken experimental design. Phospholipon® 90G, sodium deoxycholate, and sonication time, each at three levels, were selected as independent variables, while entrapment efficiency, vesicle size, and transdermal flux were identified as dependent variables. The formulation was characterized by surface morphology and shape, particle size, and zeta potential. Ex vivo transdermal flux was determined using a Hanson diffusion cell assembly, with rat skin as a barrier medium. Transfersomes from the optimized formulation were found to have spherical, unilamellar structures, with a ­homogeneous distribution and low polydispersity index (0.08. They had a particle size of 134±9 nM, with an entrapment efficiency of 91.00%±4.90%, and transdermal flux of 6.5±1.1 µg/cm2/hour. Raloxifene hydrochloride-loaded transfersomes proved significantly superior in terms of amount of drug permeated and deposited in the skin, with enhancement ratios of 6.25±1.50 and 9.25±2.40, respectively, when compared with drug-loaded conventional liposomes, and an ethanolic phosphate buffer saline. Differential scanning calorimetry study revealed a greater change in skin structure, compared with a control sample, during the ex vivo drug diffusion study. Further, confocal laser

  16. Optimal control of a fuel cell/wind/PV/grid hybrid system with thermal heat pump load

    CSIR Research Space (South Africa)

    Sichilalu, S

    2016-10-01

    Full Text Available This paper presents an optimal energy management strategy for a grid-tied photovoltaic–wind-fuel cell hybrid power supply system. The hybrid system meets the load demand consisting of an electrical load and a heat pump water heater supplying thermal...

  17. [Evaluating radiation dose load in medical personnel of radiologic diagnostic departments].

    Science.gov (United States)

    Trunov, B V; Koroleva, E P

    2014-01-01

    The article deals with materials on radiation hygienic evaluation of radiologic diagnostic departments in various medical institutions of Moscow. The studies covered work of medical staffers in X-ray examination and in contact with short-lived isotope generators. The authors outlined the examination types and stages with maximal radiation danger. Disimetric information obtained during the study helped to calculate values of equivalent, effective doses of radiation for medical personnel and maximal potential doses.

  18. Optimization of method a load cell calibration for the measurement of coefficient of friction

    Science.gov (United States)

    Castro, R. M.; Pereira, M.; Sousa, A. R.; Curi, E. I. M.; Izidoro, C. L.; Correa, L. C.

    2016-07-01

    The instrumentation of equipment for mechanical testing is used to optimize the time to deliver a result, besides minimizing errors associated with manual measurements. Given this context, this work aims to present a calibration method for a load cell to determine the measurement results of force and friction coefficient, developed from on rotary pin-on-disk tribometer. The results indicate that the procedure provides measurements reliable for the tribological phenomena, resulting in with proximity the values provided by the ASTM G99-04.

  19. Prevention of occlusive arterial thrombus formation by a single loading dose of prasugrel suppresses neointimal hyperplasia in mice.

    Science.gov (United States)

    Ohno, Kousaku; Tomizawa, Atsuyuki; Jakubowski, Joseph A; Mizuno, Makoto; Sugidachi, Atsuhiro

    2015-12-01

    The present study examined the effects of prasugrel in a mouse model of thrombosis-induced neointimal hyperplasia. Following carotid artery injury by application of ferric chloride solution, thrombus formation was assessed on Day 1 and neointimal thickening was assessed on Day 21. Single administrations of prasugrel at 0.3-3mg/kg (p.o.) resulted in a dose-related and sustained inhibition of ADP-induced platelet aggregation through 24h. Single and multiple (1 and 3 weeks) administration of prasugrel (3mg/kg loading and 1mg/kg/day maintenance doses) resulted in a marked inhibition of neointimal thickening in the injured artery. In the dose-response study, a single administration of prasugrel at 0.3-3mg/kg (p.o.) dose-relatedly inhibited thrombus formation and neointimal thickening on Days 1 and 21, respectively. The degree of neointimal hyperplasia in the injured artery correlated significantly with the thrombus indices, time to occlusion and patency rate. To explore possible mechanisms of inhibition of neointimal hyperplasia by prasugrel, mRNA expression levels of inflammatory and fibrosis markers were determined in injured arteries. Prasugrel treatment resulted in reduced MCP-1, ICAM-1 and TGF-β mRNA levels on Day 2 (24h after the injury) and Day 8 (1 week after the injury) in the target arteries. In conclusion, we found that a single oral loading dose of prasugrel markedly prevented neointimal hyperplasia by inhibiting platelet activation and thrombus formation and was associated with inhibition of the expression of inflammatory and fibrosis markers, including MCP-1, ICAM-1 and TGF-β, in the injured arteries.

  20. Low dose gemcitabine-loaded lipid nanocapsules target monocytic myeloid-derived suppressor cells and potentiate cancer immunotherapy.

    Science.gov (United States)

    Sasso, Maria Stella; Lollo, Giovanna; Pitorre, Marion; Solito, Samantha; Pinton, Laura; Valpione, Sara; Bastiat, Guillaume; Mandruzzato, Susanna; Bronte, Vincenzo; Marigo, Ilaria; Benoit, Jean-Pierre

    2016-07-01

    Tumor-induced expansion of myeloid-derived suppressor cells (MDSCs) is known to impair the efficacy of cancer immunotherapy. Among pharmacological approaches for MDSC modulation, chemotherapy with selected drugs has a considerable interest due to the possibility of a rapid translation to the clinic. However, such approach is poorly selective and may be associated with dose-dependent toxicities. In the present study, we showed that lipid nanocapsules (LNCs) loaded with a lauroyl-modified form of gemcitabine (GemC12) efficiently target the monocytic (M-) MDSC subset. Subcutaneous administration of GemC12-loaded LNCs reduced the percentage of spleen and tumor-infiltrating M-MDSCs in lymphoma and melanoma-bearing mice, with enhanced efficacy when compared to free gemcitabine. Consistently, fluorochrome-labeled LNCs were preferentially uptaken by monocytic cells rather than by other immune cells, in both tumor-bearing mice and human blood samples from healthy donors and melanoma patients. Very low dose administration of GemC12-loaded LNCs attenuated tumor-associated immunosuppression and increased the efficacy of adoptive T cell therapy. Overall, our results show that GemC12-LNCs have monocyte-targeting properties that can be useful for immunomodulatory purposes, and unveil new possibilities for the exploitation of nanoparticulate drug formulations in cancer immunotherapy.

  1. Population pharmacokinetics and dose optimization of mycophenolic acid in HCT recipients receiving oral mycophenolate mofetil.

    Science.gov (United States)

    Li, H; Mager, D E; Sandmaier, B M; Maloney, D G; Bemer, M J; McCune, J S

    2013-04-01

    We sought to create a population pharmacokinetic model for total mycophenolic acid (MPA), to study the effects of different covariates on MPA pharmacokinetics, to create a limited sampling schedule (LSS) to characterize MPA exposure (i.e., area under the curve or AUC) with maximum a posteriori Bayesian estimation, and to simulate an optimized dosing scheme for allogeneic hematopoietic cell transplantation (HCT) recipients. Four thousand four hundred ninety-six MPA concentration-time points from 408 HCT recipients were analyzed retrospectively using a nonlinear mixed effects modeling approach. MPA pharmacokinetics was characterized with a two-compartment model with first-order elimination and a time-lagged first-order absorption process. Concomitant cyclosporine and serum albumin were significant covariates. The median MPA clearance (CL) and volume of the central compartment were 24.2 L/hour and 36.4 L, respectively, for a 70 kg patient receiving tacrolimus with a serum albumin of 3.4 g/dL. Dosing simulations indicated that higher oral MMF doses are needed with concomitant cyclosporine, which increases MPA CL by 33.8%. The optimal LSS was immediately before and at 0.25 hours, 1.25 hours, 2 hours, and 4 hours after oral mycophenolate mofetil administration. MPA AUC in an individual HCT recipient can be accurately estimated using a five-sample LSS and maximum a posteriori Bayesian estimation.

  2. Partial storage optimization and load control strategy of cloud data centers.

    Science.gov (United States)

    Al Nuaimi, Klaithem; Mohamed, Nader; Al Nuaimi, Mariam; Al-Jaroodi, Jameela

    2015-01-01

    We present a novel approach to solve the cloud storage issues and provide a fast load balancing algorithm. Our approach is based on partitioning and concurrent dual direction download of the files from multiple cloud nodes. Partitions of the files are saved on the cloud rather than the full files, which provide a good optimization to the cloud storage usage. Only partial replication is used in this algorithm to ensure the reliability and availability of the data. Our focus is to improve the performance and optimize the storage usage by providing the DaaS on the cloud. This algorithm solves the problem of having to fully replicate large data sets, which uses up a lot of precious space on the cloud nodes. Reducing the space needed will help in reducing the cost of providing such space. Moreover, performance is also increased since multiple cloud servers will collaborate to provide the data to the cloud clients in a faster manner.

  3. Optimal Scheduling of Industrial Task-Continuous Load Management for Smart Power Utilization

    Directory of Open Access Journals (Sweden)

    Jidong Wang

    2017-03-01

    Full Text Available In the context of climate change and energy crisis around the world, an increasing amount of attention has been paid to developing clean energy and improving energy efficiency. The penetration of distributed generation (DG is increasing rapidly on the user’s side of an increasingly intelligent power system. This paper proposes an optimization method for industrial task-continuous load management in which distributed generation (including photovoltaic systems and wind generation and energy storage devices are both considered. To begin with, a model of distributed generation and an energy storage device are built. Then, subject to various constraints, an operation optimization problem is formulated to maximize user profit, renewable energy efficiency, and the local consumption of distributed generation. Finally, the effectiveness of the method is verified by comparing user profit under different power modes.

  4. Need for optimizing catalyst loading for achieving affordable microbial fuel cells.

    Science.gov (United States)

    Singh, Inderjeet; Chandra, Amreesh

    2013-08-01

    Microbial fuel cell (MFC) technology is a promising technology for electricity production together with simultaneous water treatment. Catalysts play an important role in deciding the MFC performance. In most reports, effect of catalyst - both type and quantity is not optimized. In this paper, synthesis of nanorods of MnO2-catalyst particles for application in Pt-free MFCs is reported. The effect of catalyst loading i.e., weight ratio, with respect to conducting element and binder has been optimized by employing large number of combinations. Using simple theoretical model, it is shown that too high (or low) concentration of catalysts result in loss of MFC performance. The operation of MFC has been investigated using domestic wastewater as source of bio-waste for obtaining real world situation. Maximum power density of ∼61 mW/m(2) was obtained when weight ratio of catalyst and conducting species was 1:1. Suitable reasons are given to explain the outcomes.

  5. Optimization of functionally graded foam-filled conical tubes under axial impact loading

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadiha, O.; Beheshti, H. [University of Isfahan, Isfahan (Iran, Islamic Republic of)

    2014-05-15

    Metallic foams as a filler in thin-walled structures can improve their crash worthiness characteristics. In this article, nonlinear parametric finite element simulations of FGF foam-filled conical tube are developed and the effect of various design parameters such as density grading, number of grading layers and the total mass of FGF tube on resulting mode shapes, specific energy absorption and initial peak load is investigated. Multi design optimization (MDO) technique and the geometrical average method, both are based on FE model are applied to maximize the specific energy absorption and minimize the impact peak force by estimating the best wall thickness and gradient exponential parameter 'm' that controls the variation of foam density. The results obtained from the optimizations indicated that functionally graded foam material, with graded density, is a suitable candidate for enhancing the crash worthiness characteristics of the structure compared to uniform density foam.

  6. Wake-Effect Minimising Optimal Control of Wind Farms, with Load Reduction

    DEFF Research Database (Denmark)

    Borchersen, Anders Bech; Larsen, Jesper Abildgaard; Sivabalan, Senthuran

    2014-01-01

    the wake effects in the farm, while maintaining optimal power output. A feature which enables the MPC to spare certain turbines, while maintaining the power output is also implemented. The MPC controller is able to minimize the wake effect in the wind farm, when the power demand is not using the full......A power generating wind turbine causes a speed reduction and an added turbulence to the wind. Wind turbines in wind farms are often caught in these wakes and are found to have a higher structural load than non affected wind turbines. This article investigates the possibility of designing a control...... strategy which optimizes the power production, while minimizing the effect of the wakes in the wind farm. A generic wind farm model which is able to calculate the wind turbines influence on each other is developed. Models for the reduction in wind speed as well as turbulence in the wake effects...

  7. STANDALONE PHOTOVOLTAIC SYSTEMS SIZING OPTIMIZATION USING DESIGN SPACE APPROACH: CASE STUDY FOR RESIDENTIAL LIGHTING LOAD

    Directory of Open Access Journals (Sweden)

    D. F. AL RIZA

    2015-07-01

    Full Text Available This paper presents a sizing optimization methodology of panel and battery capacity in a standalone photovoltaic system with lighting load. Performance of the system is identified by performing Loss of Power Supply Probability (LPSP calculation. Input data used for the calculation is the daily weather data and system components parameters. Capital Cost and Life Cycle Cost (LCC is calculated as optimization parameters. Design space for optimum system configuration is identified based on a given LPSP value, Capital Cost and Life Cycle Cost. Excess energy value is used as an over-design indicator in the design space. An economic analysis, including cost of the energy and payback period, for selected configurations are also studied.

  8. Load-dependent Optimization of Honeycombs for Sandwich Components - New Possibilities by Using Additive Layer Manufacturing

    Science.gov (United States)

    Riss, Fabian; Schilp, Johannes; Reinhart, Gunther

    Due to their feasible geometric complexity, additive layer manufacturing (ALM) processes show a highpotential for the production of lightweight components.Therefore, ALM processes enable the realization of bionic-designedcomponents like honeycombs, which are optimized depending upon load and outer boundary conditions.This optimization is based on a closed-loop, three-steps methodology: At first, each honeycomb is conformed to the surface of the part. Secondly, the structure is optimizedfor lightweight design.It is possible to achieve a homogeneous stress distribution in the part by varying the wall thickness, honeycombdiameter and the amount of honeycombs, depending on the subjected stresses and strains. At last, the functional components like threads or bearing carriers are integrated directly into the honeycomb core.Using all these steps as an iterative process, it is possible to reduce the mass of sandwich components about 50 percent compared to conventional approaches.

  9. A tumor cord model for Doxorubicin delivery and dose optimization in solid tumors

    Directory of Open Access Journals (Sweden)

    Eikenberry Steffen

    2009-08-01

    Full Text Available Abstract Background Doxorubicin is a common anticancer agent used in the treatment of a number of neoplasms, with the lifetime dose limited due to the potential for cardiotoxocity. This has motivated efforts to develop optimal dosage regimes that maximize anti-tumor activity while minimizing cardiac toxicity, which is correlated with peak plasma concentration. Doxorubicin is characterized by poor penetration from tumoral vessels into the tumor mass, due to the highly irregular tumor vasculature. I model the delivery of a soluble drug from the vasculature to a solid tumor using a tumor cord model and examine the penetration of doxorubicin under different dosage regimes and tumor microenvironments. Methods A coupled ODE-PDE model is employed where drug is transported from the vasculature into a tumor cord domain according to the principle of solute transport. Within the tumor cord, extracellular drug diffuses and saturable pharmacokinetics govern uptake and efflux by cancer cells. Cancer cell death is also determined as a function of peak intracellular drug concentration. Results The model predicts that transport to the tumor cord from the vasculature is dominated by diffusive transport of free drug during the initial plasma drug distribution phase. I characterize the effect of all parameters describing the tumor microenvironment on drug delivery, and large intercapillary distance is predicted to be a major barrier to drug delivery. Comparing continuous drug infusion with bolus injection shows that the optimum infusion time depends upon the drug dose, with bolus injection best for low-dose therapy but short infusions better for high doses. Simulations of multiple treatments suggest that additional treatments have similar efficacy in terms of cell mortality, but drug penetration is limited. Moreover, fractionating a single large dose into several smaller doses slightly improves anti-tumor efficacy. Conclusion Drug infusion time has a significant

  10. Optimal iodine dose for 3-dimensional multidetector-row CT angiography of the liver

    Energy Technology Data Exchange (ETDEWEB)

    Ichikawa, Tomoaki, E-mail: ichikawa@yamanashi.ac.jp [Department of Radiology, University of Yamanashi, Yamanashi (Japan); Motosugi, Utaroh; Morisaka, Hiroyuki; Sou, Hironobu; Onohara, Kojiro; Sano, Katsuhiro; Araki, Tsutomu [Department of Radiology, University of Yamanashi, Yamanashi (Japan)

    2012-09-15

    Purpose: To clarify the optimal iodine dose of contrast material for 3-dimensional multidetector-row CT angiography (3D-MDCTA) of the venous vasculature of the liver using volume rendering technique. Materials and methods: This study included 103 patients who were randomly assigned to 5 contrast-enhanced MDCT protocol groups with different body-weight-tailored doses of contrast material: 500, 600, 630, 650, and 700 mgI/kg body weight. The arterial, portal, and hepatic parenchymal phases were obtained to evaluate enhancement values of the aorta, portal vein, and hepatic vein. Visualization of the portal and hepatic veins on the volume-rendering images of 3D-MDCTA was evaluated using a 5-point grade. Dunnett's test was used to compare the mean enhancement value and mean grades of image quality (700 mgI/kg dose group was control). Results: The mean enhancement values of portal and hepatic vein in the group with 500 and 600 mgI/kg were significantly lower than those of the control group. During visual assessment, a significantly lower mean grades were observed in 500 mgI/kg groups for the portal vein, and 500 and 600 mgI/kg groups for hepatic vein. There were no significant intergroup differences in mean enhancement values and visual assessment among the groups using 630 mgI/kg or more. Conclusion: Iodine doses of 630 mgI/kg was recommended for 3D-MDCTA.

  11. Standardization and Optimization of Computed Tomography Protocols to Achieve Low-Dose

    Science.gov (United States)

    Chin, Cynthia; Cody, Dianna D.; Gupta, Rajiv; Hess, Christopher P.; Kalra, Mannudeep K.; Kofler, James M.; Krishnam, Mayil S.; Einstein, Andrew J.

    2014-01-01

    The increase in radiation exposure due to CT scans has been of growing concern in recent years. CT scanners differ in their capabilities and various indications require unique protocols, but there remains room for standardization and optimization. In this paper we summarize approaches to reduce dose, as discussed in lectures comprising the first session of the 2013 UCSF Virtual Symposium on Radiation Safety in Computed Tomography. The experience of scanning at low dose in different body regions, for both diagnostic and interventional CT procedures, is addressed. An essential primary step is justifying the medical need for each scan. General guiding principles for reducing dose include tailoring a scan to a patient, minimizing scan length, use of tube current modulation and minimizing tube current, minimizing-tube potential, iterative reconstruction, and periodic review of CT studies. Organized efforts for standardization have been spearheaded by professional societies such as the American Association of Physicists in Medicine. Finally, all team members should demonstrate an awareness of the importance of minimizing dose. PMID:24589403

  12. Effect of blade loading and rotor speed on the optimal aerodynamic performance of wind turbine blades

    Science.gov (United States)

    Bryson, Christopher; Hussain, Fazle; Barhorst, Alan

    2015-11-01

    Optimization of wind turbine torque as a function of angle of attack - over the entire speed range from start-up to cut-off - is studied by considering the full trigonometric relations projecting lift and drag to thrust and torque. Since driving force and thrust are geometrically constrained, one cannot be changed without affecting the other. Increasing lift to enhance torque simultaneously increases thrust, which subsequently reduces the inflow angle with respect to the rotor plane via an increased reduction in inflow velocity. Reducing the inflow angle redirects the lift force away from the driving force generating the torque, which may reduce overall torque. Similarly, changes in the tip-speed ratio (TSR) affect the inflow angle and thus the optimal torque. Using the airfoil data from the NREL 5 MW reference turbine, the optimal angle of attack over the operational TSR range (4 to 15) was computed using a BEM model to incorporate the dynamic coupling, namely the interdependency of blade loading and inflow angle. The optimal angle of attack is close to minimum drag during start-up phase (high TSR) and continuously increases toward maximum lift at high wind speeds (low TSR).

  13. Optimizing hyaluronidase dose and plasmid DNA delivery greatly improves gene electrotransfer efficiency in rat skeletal muscle

    DEFF Research Database (Denmark)

    Åkerström, Thorbjörn; Vedel, Kenneth; Needham Andersen, Josefine

    2015-01-01

    Transfection of rat skeletal muscle in vivo is a widely used research model. However, gene electrotransfer protocols have been developed for mice and yield variable results in rats. We investigated whether changes in hyaluronidase pre-treatment and plasmid DNA delivery can improve transfection...... efficiency in rat skeletal muscle. We found that pre-treating the muscle with a hyaluronidase dose suitable for rats (0.56. U/g b.w.) prior to plasmid DNA injection increased transfection efficiency by >200% whereas timing of the pre-treatment did not affect efficiency. Uniformly distributing plasmid DNA...... delivery across the muscle by increasing the number of plasmid DNA injections further enhanced transfection efficiency whereas increasing plasmid dose from 0.2 to 1.6. μg/g b.w. or vehicle volume had no effect. The optimized protocol resulted in ~80% (CI95%: 79-84%) transfected muscle fibers...

  14. Programs for Optimization of Load Distribution between Power Plants and Calculation of Equivalent Energy Characteristics of Beryozovskaya GRES

    Directory of Open Access Journals (Sweden)

    V. Shcherbich

    2013-01-01

    Full Text Available The paper presents information on elaboration of algorithms and programs for intra-station optimization of load distribution between power plants and calculation of equivalent energy characteristics the Berezovskaya GRES which is one of the components of the system for optimum load distribution between thermal power plants (TPP of the Belarusian power system. Description of the accepted technical concepts, algorithm and program structures, composition and methods for input-output data, organization of personnel work with programs of load optimization has been given in the paper.

  15. Robustness of IPSA optimized high-dose-rate prostate brachytherapy treatment plans to catheter displacements

    Science.gov (United States)

    Whitaker, May

    2016-01-01

    Purpose Inverse planning simulated annealing (IPSA) optimized brachytherapy treatment plans are characterized with large isolated dwell times at the first or last dwell position of each catheter. The potential of catheter shifts relative to the target and organs at risk in these plans may lead to a more significant change in delivered dose to the volumes of interest relative to plans with more uniform dwell times. Material and methods This study aims to determine if the Nucletron Oncentra dwell time deviation constraint (DTDC) parameter can be optimized to improve the robustness of high-dose-rate (HDR) prostate brachytherapy plans to catheter displacements. A set of 10 clinically acceptable prostate plans were re-optimized with a DTDC parameter of 0 and 0.4. For each plan, catheter displacements of 3, 7, and 14 mm were retrospectively applied and the change in dose volume histogram (DVH) indices and conformity indices analyzed. Results The robustness of clinically acceptable prostate plans to catheter displacements in the caudal direction was found to be dependent on the DTDC parameter. A DTDC value of 0 improves the robustness of planning target volume (PTV) coverage to catheter displacements, whereas a DTDC value of 0.4 improves the robustness of the plans to changes in hotspots. Conclusions The results indicate that if used in conjunction with a pre-treatment catheter displacement correction protocol and a tolerance of 3 mm, a DTDC value of 0.4 may produce clinically superior plans. However, the effect of the DTDC parameter in plan robustness was not observed to be as strong as initially suspected. PMID:27504129

  16. Robustness of IPSA optimized high-dose-rate prostate brachytherapy treatment plans to catheter displacements.

    Science.gov (United States)

    Poder, Joel; Whitaker, May

    2016-06-01

    Inverse planning simulated annealing (IPSA) optimized brachytherapy treatment plans are characterized with large isolated dwell times at the first or last dwell position of each catheter. The potential of catheter shifts relative to the target and organs at risk in these plans may lead to a more significant change in delivered dose to the volumes of interest relative to plans with more uniform dwell times. This study aims to determine if the Nucletron Oncentra dwell time deviation constraint (DTDC) parameter can be optimized to improve the robustness of high-dose-rate (HDR) prostate brachytherapy plans to catheter displacements. A set of 10 clinically acceptable prostate plans were re-optimized with a DTDC parameter of 0 and 0.4. For each plan, catheter displacements of 3, 7, and 14 mm were retrospectively applied and the change in dose volume histogram (DVH) indices and conformity indices analyzed. The robustness of clinically acceptable prostate plans to catheter displacements in the caudal direction was found to be dependent on the DTDC parameter. A DTDC value of 0 improves the robustness of planning target volume (PTV) coverage to catheter displacements, whereas a DTDC value of 0.4 improves the robustness of the plans to changes in hotspots. The results indicate that if used in conjunction with a pre-treatment catheter displacement correction protocol and a tolerance of 3 mm, a DTDC value of 0.4 may produce clinically superior plans. However, the effect of the DTDC parameter in plan robustness was not observed to be as strong as initially suspected.

  17. Pediatric Stroke and transcranial Direct Current Stimulation: Methods for Rational Individualized Dose Optimization

    Directory of Open Access Journals (Sweden)

    Bernadette T Gillick

    2014-09-01

    Full Text Available Background- Transcranial direct current stimulation (tDCS has been investigated mainly in adults and doses may not be appropriate in pediatric applications. In perinatal stroke where potential applications are promising, rational adaptation of dosage for children remains under investigation.Objective - Construct child-specific tDCS dosing parameters through case study within a perinatal stroke tDCS safety and feasibility trial. Methods- 10-year-old subject with a diagnosis of presumed perinatal ischemic stroke and hemiparesis was identified. T1 MRI scans used to derive computerized model for current flow and electrode positions. Workflow using modeling results and consideration of dosage in previous clinical trials was incorporated. Prior Ad hoc adult montages versus de novo optimized montages provided distinct risk benefit analysis. Approximating adult dose required consideration of changes in both peak brain current flow and distribution which further tradeoff between maximizing efficacy and adding safety factors. Electrode size, position, current intensity, compliance voltage, and duration were controlled independently in this process.Results- Brain electric fields modeled and compared to values previously predicted models. Approximating conservative brain current flow patterns and intensities used in previous adult trials for comparable indications, the optimal current intensity established was 0.7 mA for 10 minutes with a tDCS C3/C4 montage. Specifically 0.7 mA produced comparable peak brain current intensity of an average adult receiving 1.0 mA. Electrode size of 5x7 cm2 with 1.0 mA and low-voltage tDCS was employed to maximize tolerability. Safety and feasibility confirmed with subject tolerating the session well and no serious adverse events.Conclusion- Rational approaches to dose customization, with steps informed by computational modeling, may improve guidance for pediatric stroke tDCS trials.

  18. Optimization of hybrid iterative reconstruction level and evaluation of image quality and radiation dose for pediatric cardiac computed tomography angiography

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Lin; Liang, Changhong [Southern Medical University, Guangzhou (China); Guangdong Academy of Medical Sciences, Dept. of Radiology, Guangdong General Hospital, Guangzhou (China); Zhuang, Jian [Guangdong Academy of Medical Sciences, Dept. of Cardiac Surgery, Guangdong Cardiovascular Inst., Guangdong Provincial Key Lab. of South China Structural Heart Disease, Guangdong General Hospital, Guangzhou (China); Huang, Meiping [Guangdong Academy of Medical Sciences, Dept. of Radiology, Guangdong General Hospital, Guangzhou (China); Guangdong Academy of Medical Sciences, Dept. of Catheterization Lab, Guangdong Cardiovascular Inst., Guangdong Provincial Key Lab. of South China Structural Heart Disease, Guangdong General Hospital, Guangzhou (China); Liu, Hui [Guangdong Academy of Medical Sciences, Dept. of Radiology, Guangdong General Hospital, Guangzhou (China)

    2017-01-15

    Hybrid iterative reconstruction can reduce image noise and produce better image quality compared with filtered back-projection (FBP), but few reports describe optimization of the iteration level. We optimized the iteration level of iDose{sup 4} and evaluated image quality for pediatric cardiac CT angiography. Children (n = 160) with congenital heart disease were enrolled and divided into full-dose (n = 84) and half-dose (n = 76) groups. Four series were reconstructed using FBP, and iDose{sup 4} levels 2, 4 and 6; we evaluated subjective quality of the series using a 5-grade scale and compared the series using a Kruskal-Wallis H test. For FBP and iDose{sup 4}-optimal images, we compared contrast-to-noise ratios (CNR) and size-specific dose estimates (SSDE) using a Student's t-test. We also compared diagnostic-accuracy of each group using a Kruskal-Wallis H test. Mean scores for iDose{sup 4} level 4 were the best in both dose groups (all P < 0.05). CNR was improved in both groups with iDose{sup 4} level 4 as compared with FBP. Mean decrease in SSDE was 53% in the half-dose group. Diagnostic accuracy for the four datasets were in the range 92.6-96.2% (no statistical difference). iDose{sup 4} level 4 was optimal for both the full- and half-dose groups. Protocols with iDose{sup 4} level 4 allowed 53% reduction in SSDE without significantly affecting image quality and diagnostic accuracy. (orig.)

  19. The efficacy of magnesium sulfate loading on microalbuminuria following SIRS: One step forward in dosing.

    Science.gov (United States)

    Mirrahimi, Bahador; Hamishehkar, Hadi; Ahmadi, Arezo; Mirjalili, Mohamad Reza; Aghamohamadi, Mostafa; Najafi, Atabak; Abdollahi, Mohammad; Mojtahedzahed, Mojtaba

    2012-10-31

    Magnesium has been known for its antioxidative and antiinflammatory properties in many studies. In this study two dosing regimens of magnesium were compared with a placebo control group in order to investigate safety and efficacy of high doses of intravenous magnesium sulfate infusion on critically ill trauma patients. Inflammatory and oxidative factors were measured in this trial. 45 trauma patients with systemic inflammatory response syndromes (SIRS) were randomly assigned into 2 treatment and one placebo groups. The high dose group received 15 g MgSO4, low dose group received 7.5 g of MgSO4 over 4 hour infusion, and placebo group received saline alone. The initial and post magnesium sulfate injections levels of tumor necrosis factor alpha (TNF-α), total antioxidant power and lipid peroxidation were measured after 6, 18 and 36 hours. The pre-infusion along with 6 and 36 hour level of microalbuminuria were also determined. Repeated measurements illustrated that there was no significant difference in TNF-α, total antioxidant power and lipid peroxidation levels among groups during the period of analysis. The microalbuminuria at 36 hour post infusion of high dose group was lower than that of control group (p = 0.024). Patient's mortality (28 day) was similar among all treatment groups. Both magnesium infusion groups tolerated the drug without experiencing any complications. No evidence for antioxidative and antiinflammatory effects of magnesium in traumatic SIRS positive patients was found. Magnesium in high doses may be recommended for traumatic patients with SIRS status to prevent microalbuminuria.

  20. The Efficacy of Magnesium Sulfate Loading on Microalbuminuria Following SIRS:One Step forward in Dosing

    Directory of Open Access Journals (Sweden)

    Atabak Najafi

    2012-10-01

    Full Text Available Backgrounds:Magnesium has been known for its antioxidative and antiinflammatory properties in many studies. In this study two dosing regimens of magnesium were compared with a placebocontrol group in order to investigate safety and efficacy of high doses of intravenous magnesium sulfate infusion on critically ill trauma patients. Inflammatory and oxidative factors were measured in this trial.Methods:45 trauma patients with systemic inflammatory response syndromes (SIRS were randomly assigned into 2 treatment and one placebo groups. The high dose group received 15 g MgSO4, low dose group received 7.5 g of MgSO4 over 4 hour infusion, and placebo groupreceived saline alone. The initial and post magnesium sulfate injections levels of tumor necrosis factor alpha (TNF-α, total antioxidant power and lipid peroxidation were measured after 6, 18 and 36 hours. The pre-infusion along with 6 and 36 hour level ofmicroalbuminuria were also determined.Results:Repeated measurements illustrated that there was no significant difference in TNF-α, total antioxidant power and lipid peroxidation levels among groups during the period of analysis.The microalbuminuria at 36 hour post infusion of high dose group was lower than that of control group (p = 0.024. Patient’s mortality (28 day was similar among all treatment groups. Both magnesium infusion groups tolerated the drug without experiencing anycomplications.Conclusion:No evidence for antioxidative and antiinflammatory effects of magnesium in traumatic SIRS positive patients was found. Magnesium in high doses may be recommended for traumaticpatients with SIRS status to prevent microalbuminuria.

  1. Optimal unified combination rule in application of Dempster-Shafer theory to lung cancer radiotherapy dose response outcome analysis.

    Science.gov (United States)

    He, Yanyan; Hussaini, M Yousuff; Gong, Yutao U T; Xiao, Ying

    2016-01-08

    Our previous study demonstrated the application of the Dempster-Shafer theory of evidence to dose/volume/outcome data analysis. Specifically, it provided Yager's rule to fuse data from different institutions pertaining to radiotherapy pneumonitis versus mean lung dose. The present work is a follow-on study that employs the optimal unified combination rule, which optimizes data similarity among independent sources. Specifically, we construct belief and plausibility functions on the lung cancer radiotherapy dose outcome datasets, and then apply the optimal unified combination rule to obtain combined belief and plausibility, which bound the probabilities of pneumonitis incidence. To estimate the incidence of pneumonitis at any value of mean lung dose, we use the Lyman-Kutcher-Burman (LKB) model to fit the combined belief and plausibility curves. The results show that the optimal unified combination rule yields a narrower uncertainty range (as represented by the belief-plausibility range) than Yager's rule, which is also theoretically proven.

  2. The optimal dose of vitamin D in growing girls during academic years: a randomized trial

    OpenAIRE

    SHAKINBA, Mehrdad; TEFAGH, Samane; NAFEI, Zahra

    2011-01-01

    Prevalence of vitamin D deficiency is remarkable during childhood and adolescence throughout the world. Sufficient intake of vitamin D contributes to a number of health outcomes. The aim of this study was to specify the optimal dose of vitamin D in growing girls in a Muslim country during an academic year. Materials and methods: This randomized clinical trial study was carried out in Yazd in the center of Iran in 2007;120 junior high school girls (aged 12-15 years) were randomly divided into...

  3. A Short-Term and High-Resolution System Load Forecasting Approach Using Support Vector Regression with Hybrid Parameters Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Huaiguang [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-08-25

    This work proposes an approach for distribution system load forecasting, which aims to provide highly accurate short-term load forecasting with high resolution utilizing a support vector regression (SVR) based forecaster and a two-step hybrid parameters optimization method. Specifically, because the load profiles in distribution systems contain abrupt deviations, a data normalization is designed as the pretreatment for the collected historical load data. Then an SVR model is trained by the load data to forecast the future load. For better performance of SVR, a two-step hybrid optimization algorithm is proposed to determine the best parameters. In the first step of the hybrid optimization algorithm, a designed grid traverse algorithm (GTA) is used to narrow the parameters searching area from a global to local space. In the second step, based on the result of the GTA, particle swarm optimization (PSO) is used to determine the best parameters in the local parameter space. After the best parameters are determined, the SVR model is used to forecast the short-term load deviation in the distribution system.

  4. Preparation, characterization, and optimization of primaquine-loaded solid lipid nanoparticles

    Directory of Open Access Journals (Sweden)

    Omwoyo WN

    2014-08-01

    Full Text Available Wesley Nyaigoti Omwoyo,1,2 Bernhards Ogutu,3,4 Florence Oloo,3,5 Hulda Swai,6 Lonji Kalombo,6 Paula Melariri,6 Geoffrey Maroa Mahanga,2 Jeremiah Waweru Gathirwa3,4 1Department of Chemistry, Maasai Mara University, Narok, Kenya; 2Department of Chemistry, Jaramogi Oginga Odinga University of Science and Technology, Bondo, Kenya; 3Center for Research in Therapeutic Sciences, Strathmore University, Nairobi, Kenya; 4Kenya Medical Research Institute, Nairobi, Kenya; 5Department of Chemical Sciences and Technology, Technical University of Kenya, Nairobi, Kenya; 6Department of Polymers and Composites, Council for Scientific and Industrial Research, Pretoria, South Africa Abstract: Primaquine (PQ is one of the most widely used antimalarial drugs and is the only available drug that combats the relapsing form of malaria. PQ use in higher doses is limited by severe tissue toxicity including hematological- and gastrointestinal-related side effects. Nanoformulation of drugs in an appropriate drug carrier system has been extensively studied and shown to have the potential to improve bioavailability, thereby enhancing activity, reducing dose frequency, and subsequently reducing toxicity. The aim of this work was to design, synthesize, and characterize PQ-loaded solid lipid nanoparticles (SLNs (PQ-SLNs as a potential drug-delivery system. SLNs were prepared by a modified solvent emulsification evaporation method based on a water-in-oil-in-water (w/o/w double emulsion. The mean particle size, zeta potential, drug loading, and encapsulation efficiency of the PQ-SLNs were 236 nm, +23 mV, 14%, and 75%, respectively. The zeta potential of the SLNs changed dramatically, from -6.54 mV to +23.0 mV, by binding positively charged chitosan as surface modifier. A spherical morphology of PQ-SLNs was seen by scanning electron microscope. In vitro, release profile depicted a steady drug release over 72 hours. Differential scanning calorimeter thermograms demonstrated presence

  5. Finite Element Analysis for the Structure Optimization Design of the CPUE Load-Bearing Wheel of Tracked Vehicle

    Institute of Scientific and Technical Information of China (English)

    于立彪; 郑慕侨; 张英

    2003-01-01

    A new kind of material cast polyurethane elastomers (CPUE) is introduced to take the place of rubber on load-bearing wheel for the first time. Based on load-bearing wheel dimensions, material properties and operating conditions, the structure of wheel flange is optimized by zero-order finite element method. A detailed three-dimensional finite element model of flange of load-bearing wheel is developed and utilized to optimize structure of wheel flange. Its service life, which is affected by flange structure parameter, is analyzed by comparing the optimization results with those of prototype of wheel. The results of optimization are presented and the stress field of load-bearing wheel in optimal dimension obtained by using finite element analysis method is demonstrated. The finite element analysis and optimization results show that the CPUE load-bearing wheel is feasible and suitable for the tracked vehicle and has a guiding value in practice of the weighting design of the whole tracked vehicle.

  6. Application of PSO, Artificial Bee Colony and Bacterial Foraging Optimization algorithms to economic load dispatch: An analysis

    CERN Document Server

    Baijal, Anant; Jayabarathi, T

    2011-01-01

    This paper illustrates successful implementation of three evolutionary algorithms, namely- Particle Swarm Optimization(PSO), Artificial Bee Colony (ABC) and Bacterial Foraging Optimization (BFO) algorithms to economic load dispatch problem (ELD). Power output of each generating unit and optimum fuel cost obtained using all three algorithms have been compared. The results obtained show that ABC and BFO algorithms converge to optimal fuel cost with reduced computational time when compared to PSO for the two example problems considered.

  7. Preparation of finasteride capsules-loaded drug nanoparticles: formulation, optimization, in vitro, and pharmacokinetic evaluation

    Directory of Open Access Journals (Sweden)

    Ahmed TA

    2016-02-01

    Full Text Available Tarek A Ahmed1,2 1Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia; 2Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Al-Azhar University, Cairo, Egypt Abstract: In this study, optimized freeze-dried finasteride nanoparticles (NPs were prepared from drug nanosuspension formulation that was developed using the bottom–up technique. The effects of four formulation and processing variables that affect the particle size and solubility enhancement of the NPs were explored using the response surface optimization design. The optimized formulation was morphologically characterized using transmission electron microscopy (TEM. Physicochemical interaction among the studied components was investigated. Crystalline change was investigated using X-ray powder diffraction (XRPD. Crystal growth of the freeze-dried NPs was compared to the corresponding aqueous drug nanosuspension. Freeze-dried NPs formulation was subsequently loaded into hard gelatin capsules that were examined for in vitro dissolution and pharmacokinetic behavior. Results revealed that in most of the studied variables, some of the quadratic and interaction effects had a significant effect on the studied responses. TEM image illustrated homogeneity and shape of the prepared NPs. No interaction among components was noticed. XRPD confirmed crystalline state change in the optimized NPs. An enhancement in the dissolution rate of more than 2.5 times from capsules filled with optimum drug NPs, when compared to capsules filled with pure drug, was obtained. Crystal growth, due to Ostwald ripening phenomenon and positive Gibbs free energy, was reduced following lyophilization of the nanosuspension formulation. Pharmacokinetic parameters from drug NPs were superior to that of pure drug and drug microparticles. In conclusion, freeze-dried NPs based on drug nanosuspension formulation is a successful

  8. Scanning protocol optimization and dose evaluation in coronary stenosis using multi-slices computed tomography

    Science.gov (United States)

    Huang, Yung-hui; Chen, Chia-lin; Sheu, Chin-yin; Lee, Jason J. S.

    2007-02-01

    Cardiovascular diseases are the most common incidence for premature death in developed countries. A major fraction is attributable to atherosclerotic coronary artery disease, which may result in sudden cardiac failure. A reduction of mortality caused by myocardial infarction may be achieved if coronary atherosclerosis can be detected and treated at an early stage before symptoms occur. Therefore, there is need for an effective tool that allows identification of patients at increased risk for future cardiac events. The current multi-detector CT has been widely used for detection and quantification of coronary calcifications as a sign of coronary atherosclerosis. The aim of this study is to optimize the diagnostic values and radiation exposure in coronary artery calcium-screening examination using multi-slice CT (MSCT) with different image scan protocols. The radiation exposure for all protocols is evaluated by using computed tomography dose index (CTDI) phantom measurements. We chose an optimal scanning protocol and evaluated patient radiation dose in the MSCT coronary artery screenings and preserved its expecting diagnostic accuracy. These changes make the MSCT have more operation flexibility and provide more diagnostic values in current practice.

  9. Design, optimization and evaluation of a "smart" pixel sensor array for low-dose digital radiography

    Science.gov (United States)

    Wang, Kai; Liu, Xinghui; Ou, Hai; Chen, Jun

    2016-04-01

    Amorphous silicon (a-Si:H) thin-film transistors (TFTs) have been widely used to build flat-panel X-ray detectors for digital radiography (DR). As the demand for low-dose X-ray imaging grows, a detector with high signal-to-noise-ratio (SNR) pixel architecture emerges. "Smart" pixel is intended to use a dual-gate photosensitive TFT for sensing, storage, and switch. It differs from a conventional passive pixel sensor (PPS) and active pixel sensor (APS) in that all these three functions are combined into one device instead of three separate units in a pixel. Thus, it is expected to have high fill factor and high spatial resolution. In addition, it utilizes the amplification effect of the dual-gate photosensitive TFT to form a one-transistor APS that leads to a potentially high SNR. This paper addresses the design, optimization and evaluation of the smart pixel sensor and array for low-dose DR. We will design and optimize the smart pixel from the scintillator to TFT levels and validate it through optical and electrical simulation and experiments of a 4x4 sensor array.

  10. The fixed-point iteration method for IMRT optimization with truncated dose deposition coefficient matrix

    CERN Document Server

    Tian, Zhen; Jia, Xun; Jiang, Steve B

    2013-01-01

    In the treatment plan optimization for intensity modulated radiation therapy (IMRT), dose-deposition coefficient (DDC) matrix is often pre-computed to parameterize the dose contribution to each voxel in the volume of interest from each beamlet of unit intensity. However, due to the limitation of computer memory and the requirement on computational efficiency, in practice matrix elements of small values are usually truncated, which inevitably compromises the quality of the resulting plan. A fixed-point iteration scheme has been applied in IMRT optimization to solve this problem, which has been reported to be effective and efficient based on the observations of the numerical experiments. In this paper, we aim to point out the mathematics behind this scheme and to answer the following three questions: 1) whether the fixed-point iteration algorithm converges or not? 2) when it converges, whether the fixed point solution is same as the original solution obtained with the complete DDC matrix? 3) if not the same, wh...

  11. Application of PK/PD Modeling in Veterinary Field: Dose Optimization and Drug Resistance Prediction

    Directory of Open Access Journals (Sweden)

    Ijaz Ahmad

    2016-01-01

    Full Text Available Among veterinary drugs, antibiotics are frequently used. The true mean of antibiotic treatment is to administer dose of drug that will have enough high possibility of attaining the preferred curative effect, with adequately low chance of concentration associated toxicity. Rising of antibacterial resistance and lack of novel antibiotic is a global crisis; therefore there is an urgent need to overcome this problem. Inappropriate antibiotic selection, group treatment, and suboptimal dosing are mostly responsible for the mentioned problem. One approach to minimizing the antibacterial resistance is to optimize the dosage regimen. PK/PD model is important realm to be used for that purpose from several years. PK/PD model describes the relationship between drug potency, microorganism exposed to drug, and the effect observed. Proper use of the most modern PK/PD modeling approaches in veterinary medicine can optimize the dosage for patient, which in turn reduce toxicity and reduce the emergence of resistance. The aim of this review is to look at the existing state and application of PK/PD in veterinary medicine based on in vitro, in vivo, healthy, and disease model.

  12. Optimal Dose of Epidural Dexmedetomidine Added to Ropivacaine for Epidural Labor Analgesia: A Pilot Study

    Directory of Open Access Journals (Sweden)

    Zhang Wangping

    2017-01-01

    Full Text Available Background. Dexmedetomidine combined with local anesthetics can decrease the concentration of epidural ropivacaine. However, the optimal dose of epidural dexmedetomidine combined with ropivacaine for labor analgesia is still uncertain. This study investigated the effect of adding different dose of epidural dexmedetomidine to ropivacaine during epidural labor analgesia. Methods. One hundred women were randomly assigned to one of the four groups (Groups A, B, C, and D received 0.25, 0.5, 0.75, and 1 μg/ml of dexmedetomidine plus 0.1% ropivacaine, resp.. The onset of epidural anesthesia and stages of labor were studied, and pain was assessed using a visual analogue scale (VAS. Hemodynamic parameters and fetal heart rate were monitored. Apgar scores and umbilical artery pH were recorded. The side effects, if any, were recorded also. Results. The addition of 0.25, 0.5, and 0.75 μg/ml of dexmedetomidine to 0.1% ropivacaine provided safe and effective analgesia, but 1 μg/ml of dexmedetomidine resulted in increasing incidence of motor block. The hemodynamic parameters were similar between groups (P>0.05. Side effects in Group D were significantly higher than those in the other three groups (P<0.05. Conclusions. When dexmedetomidine is combined with 0.1% ropivacaine, the optimal concentration of dexmedetomidine is 0.5 μg/ml for epidural labor analgesia (this trial is registered with ChiCTR-OPC-16008548.

  13. Optimization of {beta}-carotene loaded solid lipid nanoparticles preparation using a high shear homogenization technique

    Energy Technology Data Exchange (ETDEWEB)

    Triplett, Michael D., E-mail: triplettm@battelle.or [Battelle Memorial Institute, Health and Life Sciences Global Business (United States); Rathman, James F. [The Ohio State University, Department of Chemical and Biomolecular Engineering (United States)

    2009-04-15

    Using statistical experimental design methodologies, the solid lipid nanoparticle design space was found to be more robust than previously shown in literature. Formulation and high shear homogenization process effects on solid lipid nanoparticle size distribution, stability, drug loading, and drug release have been investigated. Experimentation indicated stearic acid as the optimal lipid, sodium taurocholate as the optimal cosurfactant, an optimum lecithin to sodium taurocholate ratio of 3:1, and an inverse relationship between mixing time and speed and nanoparticle size and polydispersity. Having defined the base solid lipid nanoparticle system, {beta}-carotene was incorporated into stearic acid nanoparticles to investigate the effects of introducing a drug into the base solid lipid nanoparticle system. The presence of {beta}-carotene produced a significant effect on the optimal formulation and process conditions, but the design space was found to be robust enough to accommodate the drug. {beta}-Carotene entrapment efficiency averaged 40%. {beta}-Carotene was retained in the nanoparticles for 1 month. As demonstrated herein, solid lipid nanoparticle technology can be sufficiently robust from a design standpoint to become commercially viable.

  14. Study of the Effect of Iron Loaded with B4C on the Total Gamma Doses Emitted from Laminated Shield

    Science.gov (United States)

    Makarious, A. S.; Maayouf, R. M. A.; Megahid, R. M.; El-Sayed Abdo, A.

    In this work a comparative study of the effect of iron loaded with B4C on the suppression of gamma-rays in a laminated shield of water, iron and either ordinary or limenite concrete have been carried out. It was found that B4C loaded with iron has a remarkable effect on the suppression of gamma doses all through the laminated shield. The suppression is more pronounced in the concrete layer. It was also found that the decrease of gamma doses in ilmenite concrete is 1.7 that one for ordinary concrete.Translated AbstractUntersuchung des Einflusses von mit B4C angereichertem Eisen auf die Gesamt-Gamma-Dosis aus einem laminierten SchildDer Effekt von mit B4C angereichertem Eisen auf die Abschirmung von Gamma-Strahlen durch einen laminierten Schild aus Wasser, Eisen und entweder gewöhnlichem oder Ilmenitebeton wird vergleichend untersucht. Es erweist sich ein bemerkenswerter Effekt des angereicherten Eisens auf die Abschwächung der Gamma-Dosis im gesamten Schild. Sie ist in der Betonschicht am ausgeprägtesten. Die Abnahme der Gamma-Dosis in Ilmenitebeton ist etwa 1,7fach der in gewöhnlichem Beton.

  15. Efficacy and tolerability of a high loading dose (25,000 IU weekly) vitamin D3 supplementation in obese children with vitamin D insufficiency/deficiency

    NARCIS (Netherlands)

    Radhakishun, Nalini N E; van Vliet, Mariska; Poland, Dennis C W; Weijer, Olivier; Beijnen, Jos H; Brandjes, Dees P M; Diamant, Michaela; von Rosenstiel, Ines A

    2014-01-01

    BACKGROUND: The recommended dose of vitamin D supplementation of 400 IU/day might be inadequate to treat obese children with vitamin D insufficiency. Therefore, we tested the efficacy and tolerability of a high loading dose vitamin D3 supplementation of 25,000 IU weekly in multiethnic obese children

  16. Efficacy and tolerability of a high loading dose (25,000 IU weekly) vitamin D3 supplementation in obese children with vitamin D insufficiency/deficiency

    NARCIS (Netherlands)

    Radhakishun, Nalini N E; van Vliet, Mariska; Poland, Dennis C W; Weijer, Olivier; Beijnen, Jos H; Brandjes, Dees P M; Diamant, Michaela; von Rosenstiel, Ines A

    2014-01-01

    BACKGROUND: The recommended dose of vitamin D supplementation of 400 IU/day might be inadequate to treat obese children with vitamin D insufficiency. Therefore, we tested the efficacy and tolerability of a high loading dose vitamin D3 supplementation of 25,000 IU weekly in multiethnic obese

  17. Optimizing radiation dose by using advanced modelled iterative reconstruction in high-pitch coronary CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Gordic, Sonja; Husarik, Daniela B.; Alkadhi, Hatem [University Hospital Zurich, University of Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland); Desbiolles, Lotus; Leschka, Sebastian [University Hospital Zurich, University of Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland); Kantonsspital, Divison of Radiology and Nuclear Medicine, St. Gallen (Switzerland); Sedlmair, Martin; Schmidt, Bernhard [Siemens Healthcare, Computed Tomography Division, Forchheim (Germany); Manka, Robert [University Hospital Zurich, University of Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland); University Hospital Zurich, University of Zurich, Clinic of Cardiology, Zurich (Switzerland); University and ETH Zurich, Institute for Biomedical Engineering, Zurich (Switzerland); Plass, Andre; Maisano, Francesco [University Hospital Zurich, University of Zurich, Clinic for Cardiovascular Surgery, Zurich (Switzerland); Wildermuth, Simon [Kantonsspital, Divison of Radiology and Nuclear Medicine, St. Gallen (Switzerland)

    2016-02-15

    To evaluate the potential of advanced modeled iterative reconstruction (ADMIRE) for optimizing radiation dose of high-pitch coronary CT angiography (CCTA). High-pitch 192-slice dual-source CCTA was performed in 25 patients (group 1) according to standard settings (ref. 100 kVp, ref. 270 mAs/rot). Images were reconstructed with filtered back projection (FBP) and ADMIRE (strength levels 1-5). In another 25 patients (group 2), high-pitch CCTA protocol parameters were adapted according to results from group 1 (ref. 160 mAs/rot), and images were reconstructed with ADMIRE level 4. In ten patients of group 1, vessel sharpness using full width at half maximum (FWHM) analysis was determined. Image quality was assessed by two independent, blinded readers. Interobserver agreements for attenuation and noise were excellent (r = 0.88/0.85, p < 0.01). In group 1, ADMIRE level 4 images were most often selected (84 %, 21/25) as preferred data set; at this level noise reduction was 40 % compared to FBP. Vessel borders showed increasing sharpness (FWHM) at increasing ADMIRE levels (p < 0.05). Image quality in group 2 was similar to that of group 1 at ADMIRE levels 2-3. Radiation dose in group 2 (0.3 ± 0.1 mSv) was significantly lower than in group 1 (0.5 ± 0.3 mSv; p < 0.05). In a selected population, ADMIRE can be used for optimizing high-pitch CCTA to an effective dose of 0.3 mSv. (orig.)

  18. Asymmetric dose-volume optimization with smoothness control for rotating-shield brachytherapy.

    Science.gov (United States)

    Liu, Yunlong; Flynn, Ryan T; Kim, Yusung; Wu, Xiaodong

    2014-11-01

    It is important to reduce fluence map complexity in rotating-shield brachytherapy (RSBT) inverse planning to improve delivery efficiency while maintaining plan quality. This study proposes an efficient and effective RSBT dose optimization method which enables to produce smooth fluence maps. Five cervical cancer patients each with a high-risk clinical-target-volume (HR-CTV) larger than 40 cm(3) were considered as the test cases. The RSBT source was a partially shielded electronic brachytherapy source (Xoft Axxent™). The anchor RSBT plans generated by the asymmetric dose-volume optimization with smoothness control (ADOS) method were compared against those produced by the dose-surface optimization (DSO) method and inverse-planning with simulated annealing (IPSA). Either L1-norm or L2-norm was used to measure the smoothness of a fluence map in the proposed ADOS method as one weighted term of the objective function. Uniform dwell-time scaling was applied to all plans such that HR-CTV D90 was maximized without violating the D2cc tolerances of the rectum, bladder, and sigmoid colon. The quality of the anchor plans was measured with HR-CTV D90 of the anchor plans. Single-shielded RSBT [(S-RSBT), RSBT with single, fix sized delivery window] and dynamic-sheilded RSBT [(D-RSBT), RSBT with dynamically varying sized delivery window] delivery plans generated based on the anchor plans were also measured, with delivery time constraints of 10, 20, and 30 min/fraction (fx). The average HR-CTV D90 values of the anchor plans achieved by the ADOS, DSO, and IPSA methods were 111.5, 94.2, and 107.4 Gy, respectively, where the weighting parameter β used in ADOS with L2-norm was set to be 100. By using S-RSBT sequencing and 20 min/fx delivery time, the corresponding D90 values were 88.8, 81.9, and 83.4 Gy; while using D-RSBT sequencing with 20 min/fx delivery time, the corresponding D90 values were 91.4, 88.3, and 78.9 Gy, respectively. The average optimization times for ADOS, DSO, and

  19. Adaptation of the CVT algorithm for catheter optimization in high dose rate brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Poulin, Eric; Fekete, Charles-Antoine Collins; Beaulieu, Luc [Département de Physique, de Génie Physique et d’Optique et Centre de recherche sur le cancer de l’Université Laval, Université Laval, Québec, Québec G1V 0A6, Canada and Département de Radio-Oncologie et Axe oncologie du Centre de Recherche du CHU de Québec, CHU de Québec, 11 Côte du Palais, Québec, Québec G1R 2J6 (Canada); Létourneau, Mélanie [Département de Radio-Oncologie, CHU de Québec, 11 Côte du Palais, Québec, Québec G1R 2J6 (Canada); Fenster, Aaron [Imaging Research Laboratories, Robarts Research Institute, 100 Perth Drive, London, Ontario N6A 5K8 (United Kingdom); Pouliot, Jean [Department of Radiation Oncology, University of California San Francisco, Helen Diller Family Comprehensive Cancer Center, 1600 Divisadero Street, San Francisco, California 94143-1708 (United States)

    2013-11-15

    Purpose: An innovative, simple, and fast method to optimize the number and position of catheters is presented for prostate and breast high dose rate (HDR) brachytherapy, both for arbitrary templates or template-free implants (such as robotic templates).Methods: Eight clinical cases were chosen randomly from a bank of patients, previously treated in our clinic to test our method. The 2D Centroidal Voronoi Tessellations (CVT) algorithm was adapted to distribute catheters uniformly in space, within the maximum external contour of the planning target volume. The catheters optimization procedure includes the inverse planning simulated annealing algorithm (IPSA). Complete treatment plans can then be generated from the algorithm for different number of catheters. The best plan is chosen from different dosimetry criteria and will automatically provide the number of catheters and their positions. After the CVT algorithm parameters were optimized for speed and dosimetric results, it was validated against prostate clinical cases, using clinically relevant dose parameters. The robustness to implantation error was also evaluated. Finally, the efficiency of the method was tested in breast interstitial HDR brachytherapy cases.Results: The effect of the number and locations of the catheters on prostate cancer patients was studied. Treatment plans with a better or equivalent dose distributions could be obtained with fewer catheters. A better or equal prostate V100 was obtained down to 12 catheters. Plans with nine or less catheters would not be clinically acceptable in terms of prostate V100 and D90. Implantation errors up to 3 mm were acceptable since no statistical difference was found when compared to 0 mm error (p > 0.05). No significant difference in dosimetric indices was observed for the different combination of parameters within the CVT algorithm. A linear relation was found between the number of random points and the optimization time of the CVT algorithm. Because the

  20. Preparation of finasteride capsules-loaded drug nanoparticles: formulation, optimization, in vitro, and pharmacokinetic evaluation

    Science.gov (United States)

    Ahmed, Tarek A

    2016-01-01

    In this study, optimized freeze-dried finasteride nanoparticles (NPs) were prepared from drug nanosuspension formulation that was developed using the bottom–up technique. The effects of four formulation and processing variables that affect the particle size and solubility enhancement of the NPs were explored using the response surface optimization design. The optimized formulation was morphologically characterized using transmission electron microscopy (TEM). Physicochemical interaction among the studied components was investigated. Crystalline change was investigated using X-ray powder diffraction (XRPD). Crystal growth of the freeze-dried NPs was compared to the corresponding aqueous drug nanosuspension. Freeze-dried NPs formulation was subsequently loaded into hard gelatin capsules that were examined for in vitro dissolution and pharmacokinetic behavior. Results revealed that in most of the studied variables, some of the quadratic and interaction effects had a significant effect on the studied responses. TEM image illustrated homogeneity and shape of the prepared NPs. No interaction among components was noticed. XRPD confirmed crystalline state change in the optimized NPs. An enhancement in the dissolution rate of more than 2.5 times from capsules filled with optimum drug NPs, when compared to capsules filled with pure drug, was obtained. Crystal growth, due to Ostwald ripening phenomenon and positive Gibbs free energy, was reduced following lyophilization of the nanosuspension formulation. Pharmacokinetic parameters from drug NPs were superior to that of pure drug and drug microparticles. In conclusion, freeze-dried NPs based on drug nanosuspension formulation is a successful technique in enhancing stability, solubility, and in vitro dissolution of poorly water-soluble drugs with possible impact on the drug bioavailability. PMID:26893559

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

    Science.gov (United States)

    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.

  2. Optimization of pre-sowing magnetic field doses through RSM in pea

    Science.gov (United States)

    Iqbal, M.; Ahmad, I.; Hussain, S. M.; Khera, R. A.; Bokhari, T. H.; Shehzad, M. A.

    2013-09-01

    Seed pre-sowing magnetic field treatment was reported to induce biochemical and physiological changes. In the present study, response surface methodology was used for deduction of optimal magnetic field doses. Improved growth and yield responses in the pea cultivar were achieved using a rotatable central composite design and multivariate data analysis. The growth parameters such as root and shoot fresh masses and lengths as well as yield were enhanced at a certain magnetic field level. The chlorophyll contents were also enhanced significantly vs. the control. The low magnetic field strength for longer duration of exposure/ high strength for shorter exposure were found to be optimal points for maximum responses in root fresh mass, chlorophyll `a' contents, and green pod yield/plant, respectively and a similar trend was observed for other measured parameters. The results indicate that the magnetic field pre-sowing seed treatment can be used practically to enhance the growth and yield in pea cultivar and response surface methodology was found an efficient experimental tool for optimization of the treatment level to obtain maximum response of interest.

  3. Cooling load and COP optimization of an irreversible Carnot refrigerator with spin-1/2 systems

    Directory of Open Access Journals (Sweden)

    Xiaowei Liu, Lingen Chen, Feng Wu, Fengrui Sun

    2011-09-01

    Full Text Available A model of an irreversible quantum refrigerator with working medium consisting of many non-interacting spin-1/2 systems is established in this paper. The quantum refrigeration cycle is composed of two isothermal processes and two irreversible adiabatic processes and is referred to as a spin quantum Carnot refrigeration cycle. Expressions of some important performance parameters, such as cycle period, cooling load and coefficient of performance (COP for the irreversible spin quantum Carnot refrigerator are derived, and detailed numerical examples are provided. The optimal performance of the quantum refrigerator at high temperature limit is analyzed with numerical examples. Effects of internal irreversibility and heat leakage on the performance are discussed in detail. The endoreversible case, frictionless case and the case without heat leakage are discussed in brief.

  4. A Parallel Interval Computation Model for Global Optimization with Automatic Load Balancing

    Institute of Scientific and Technical Information of China (English)

    Yong Wu; Arun Kumar

    2012-01-01

    In this paper,we propose a decentralized parallel computation model for global optimization using interval analysis.The model is adaptive to any number of processors and the workload is automatically and evenly distributed among all processors by alternative message passing.The problems received by each processor are processed based on their local dominance properties,which avoids unnecessary interval evaluations.Further,the problem is treated as a whole at the beginning of computation so that no initial decomposition scheme is required.Numerical experiments indicate that the model works well and is stable with different number of parallel processors,distributes the load evenly among the processors,and provides an impressive speedup,especially when the problem is time-consuming to solve.

  5. Brachytherapy optimization using radiobiological-based planning for high dose rate and permanent implants for prostate cancer treatment

    Science.gov (United States)

    Seeley, Kaelyn; Cunha, J. Adam; Hong, Tae Min

    2017-01-01

    We discuss an improvement in brachytherapy--a prostate cancer treatment method that directly places radioactive seeds inside target cancerous regions--by optimizing the current standard for delivering dose. Currently, the seeds' spatiotemporal placement is determined by optimizing the dose based on a set of physical, user-defined constraints. One particular approach is the ``inverse planning'' algorithms that allow for tightly fit isodose lines around the target volumes in order to reduce dose to the patient's organs at risk. However, these dose distributions are typically computed assuming the same biological response to radiation for different types of tissues. In our work, we consider radiobiological parameters to account for the differences in the individual sensitivities and responses to radiation for tissues surrounding the target. Among the benefits are a more accurate toxicity rate and more coverage to target regions for planning high-dose-rate treatments as well as permanent implants.

  6. Automatic boiling water reactor loading pattern design using ant colony optimization algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Wang, C.-D. [Department of Engineering and System Science, National Tsing Hua University, 101, Section 2 Kuang Fu Road, Hsinchu 30013, Taiwan (China); Nuclear Engineering Division, Institute of Nuclear Energy Research, No. 1000, Wenhua Rd., Jiaan Village, Longtan Township, Taoyuan County 32546, Taiwan (China)], E-mail: jdwang@iner.gov.tw; Lin Chaung [Department of Engineering and System Science, National Tsing Hua University, 101, Section 2 Kuang Fu Road, Hsinchu 30013, Taiwan (China)

    2009-08-15

    An automatic boiling water reactor (BWR) loading pattern (LP) design methodology was developed using the rank-based ant system (RAS), which is a variant of the ant colony optimization (ACO) algorithm. To reduce design complexity, only the fuel assemblies (FAs) of one eight-core positions were determined using the RAS algorithm, and then the corresponding FAs were loaded into the other parts of the core. Heuristic information was adopted to exclude the selection of the inappropriate FAs which will reduce search space, and thus, the computation time. When the LP was determined, Haling cycle length, beginning of cycle (BOC) shutdown margin (SDM), and Haling end of cycle (EOC) maximum fraction of limit for critical power ratio (MFLCPR) were calculated using SIMULATE-3 code, which were used to evaluate the LP for updating pheromone of RAS. The developed design methodology was demonstrated using FAs of a reference cycle of the BWR6 nuclear power plant. The results show that, the designed LP can be obtained within reasonable computation time, and has a longer cycle length than that of the original design.

  7. Optimal RTP Based Power Scheduling for Residential Load in Smart Grid

    Science.gov (United States)

    Joshi, Hemant I.; Pandya, Vivek J.

    2015-12-01

    To match supply and demand, shifting of load from peak period to off-peak period is one of the effective solutions. Presently flat rate tariff is used in major part of the world. This type of tariff doesn't give incentives to the customers if they use electrical energy during off-peak period. If real time pricing (RTP) tariff is used, consumers can be encouraged to use energy during off-peak period. Due to advancement in information and communication technology, two-way communications is possible between consumers and utility. To implement this technique in smart grid, home energy controller (HEC), smart meters, home area network (HAN) and communication link between consumers and utility are required. HEC interacts automatically by running an algorithm to find optimal energy consumption schedule for each consumer. However, all the consumers are not allowed to shift their load simultaneously during off-peak period to avoid rebound peak condition. Peak to average ratio (PAR) is considered while carrying out minimization problem. Linear programming problem (LPP) method is used for minimization. The simulation results of this work show the effectiveness of the minimization method adopted. The hardware work is in progress and the program based on the method described here will be made to solve real problem.

  8. B3: Fuzzy-Based Data Center Load Optimization in Cloud Computing

    Directory of Open Access Journals (Sweden)

    M. Jaiganesh

    2013-01-01

    Full Text Available Cloud computing started a new era in getting variety of information puddles through various internet connections by any connective devices. It provides pay and use method for grasping the services by the clients. Data center is a sophisticated high definition server, which runs applications virtually in cloud computing. It moves the application, services, and data to a large data center. Data center provides more service level, which covers maximum of users. In order to find the overall load efficiency, the utilization service in data center is a definite task. Hence, we propose a novel method to find the efficiency of the data center in cloud computing. The goal is to optimize date center utilization in terms of three big factors—Bandwidth, Memory, and Central Processing Unit (CPU cycle. We constructed a fuzzy expert system model to obtain maximum Data Center Load Efficiency (DCLE in cloud computing environments. The advantage of the proposed system lies in DCLE computing. While computing, it allows regular evaluation of services to any number of clients. This approach indicates that the current cloud needs an order of magnitude in data center management to be used in next generation computing.

  9. A Novel Dynamic Adjusting Algorithm for Load Balancing and Handover Co-Optimization in LTE SON

    Institute of Scientific and Technical Information of China (English)

    Wen-Yu Li; Xiang Zhang; Shu-Cong Jia; Xin-Yu Gu; Lin Zhang; Xiao-Yu Duan; Jia-Ru Lin

    2013-01-01

    With the development of mobile internet and multi-media service,advanced techniques need to be applied in wireless network to improve user experience.Long term evolution (LTE) systems,which can offer up to 100Mbps downlink date rates,have been deployed in USA and Korea.However,because plenty of complex physical layer algorithms are utilized,network planning and optimization become heavy burdens for LTE network operators.Self-organizing network (SON) is a promising method to overcome this problem by automatically selecting and adjusting key parameters in LTE systems.In this paper,we present a dynamic adjusting algorithm to improve both handover and load balancing performance by introducing a weighted co-satisfaction factor (CSF).Analysis and system level simulation are conducted to exhibit the performance improvement of the proposed scheme.Results show that the proposed method outperforms the conventional solutions in terms of the network handover success ratio and load balancing gains significantly.

  10. Impact of optimal load response to real-time electricity price on power system constraints in Denmark

    DEFF Research Database (Denmark)

    Hu, Weihao; Chen, Zhe; Bak-Jensen, Birgitte

    2010-01-01

    and may represent the future of electricity markets in some ways, is chosen as the studied power system in this paper. A distribution system where wind power capacity is 126% of maximum loads is chosen as the study case. This paper presents a nonlinear load optimization method to real-time power price...... for demand side management in order to save the energy costs as much as possible. Simulation results show that the optimal load response to a real-time electricity price has some good impacts on power system constraints in a distribution system with high wind power penetrations....... for demand side management generates different load profiles and may have some impacts on power system constraints, such as voltage limits and capacity limits. The western Danish power system, which is currently the grid area in the world that has the largest share of wind power in its generation profiles...

  11. Optimization of the RF cavity heat load and trip rates for CEBAF at 12 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, He [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Roblin, Yves R. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Freyberger, Arne P. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Krafft, Geoffrey A. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Terzic, Balsa P. [Old Dominion Univ., Norfolk, VA (United States)

    2017-05-01

    The Continuous Electron Beam Accelerator Facility at JLab has 200 RF cavities in the north linac and the south linac respectively after the 12 GeV upgrade. The purpose of this work is to simultaneously optimize the heat load and the trip rate for the cavities and to reconstruct the pareto-optimal front in a timely manner when some of the cavities are turned down. By choosing an efficient optimizer and strategically creating the initial gradients, the pareto-optimal front for no more than 15 cavities down can be re-established within 20 seconds.

  12. Patient-optimized doses of fesoterodine improve bladder symptoms in an open-label, flexible-dose study.

    Science.gov (United States)

    Wyndaele, Jean-Jacques; Goldfischer, Evan R; Morrow, Jon D; Gong, Jason; Tseng, Li-Jung; Choo, Myung-Soo

    2011-02-01

    To assess changes in overactive bladder (OAB) symptoms and patient-reported outcomes in a post hoc analysis in which subjects from a 12-week, open-label, flexible-dose fesoterodine study were stratified according to whether they opted for dose escalation. Subjects with OAB (eight or more micturitions and three or more urgency episodes per 24 h) who reported dissatisfaction with tolterodine within 2 years of screening received fesoterodine 4 mg once daily for 4 weeks, with an optional dose increase to 8 mg after week 4 based on discussion of efficacy and tolerability between the subject and investigator. Subjects completed 5-day diaries, the Patient Perception of Bladder Condition (PPBC) and Urgency Perception Scale (UPS) at baseline and weeks 4 and 12, and the Overactive Bladder Questionnaire (OAB-q) at baseline and week 12. Subjects rated treatment satisfaction at week 12. Dose escalation to 8 mg at week 4 was chosen by 255 (50%) of 513 subjects. At baseline, subjects who opted for dose escalation at week 4 (escalators) had significantly higher means for all diary variables except urgency urinary incontinence (UUI) episodes, significantly greater OAB-q Symptom Bother scores and significantly lower OAB-q health-related quality of life (HRQL) scores (all P fesoterodine significantly improved OAB symptoms and patient-reported outcomes in subjects who chose to remain on the initial 4-mg dose, as well as in the 50% of subjects who escalated to the 8-mg dose after 4 weeks. Non-escalators had significantly fewer OAB symptoms at baseline and significantly greater improvements than escalators before dose escalation. Escalators showed increased symptom relief after dose escalation; improvements in most outcomes were similar among non-escalators and escalators by week 12. Flexible-dose fesoterodine was well tolerated, with similar adverse-event profiles observed in the escalator and non-escalator groups. These results may help clinicians to identify patients more likely to

  13. Pharmacodynamics of dose-escalated 'front-loading' polymyxin B regimens against polymyxin-resistant mcr-1-harbouring Escherichia coli.

    Science.gov (United States)

    Smith, Nicholas M; Bulman, Zackery P; Sieron, Arthur O; Bulitta, Jürgen B; Holden, Patricia N; Nation, Roger L; Li, Jian; Wright, Gerard D; Tsuji, Brian T

    2017-08-01

    Gram-negative bacteria harbouring the mcr-1 plasmid are resistant to the 'last-line' polymyxins and have been reported worldwide. Our objective was to define the impact of increasing the initial polymyxin B dose intensity against an mcr-1 -harbouring strain to delineate the impact of plasmid-mediated polymyxin resistance on the dynamics of bacterial killing and resistance. A hollow fibre infection model (HFIM) was used to simulate polymyxin B regimens against an mcr-1 -harbouring Escherichia coli (MIC 8 mg/L) over 10 days. Four escalating polymyxin B 'front-loading' regimens (3.33, 6.66, 13.3 or 26.6 mg/kg for one dose followed by 1.43 mg/kg every 12 h starting 12 h later) simulating human pharmacokinetics were utilized in the HFIM. A mechanism-based, mathematical model was developed using S-ADAPT to characterize bacterial killing. The 3.33 mg/kg 'front-loading' regimen resulted in regrowth mirroring the growth control. The 6.66, 13.3 and 26.6 mg/kg 'front-loading' regimens resulted in maximal bacterial reductions of 1.91, 3.79 and 6.14 log 10 cfu/mL, respectively. Irrespective of the early polymyxin B exposure (24 h AUC), population analysis profiles showed similar growth of polymyxin B-resistant subpopulations. The HFIM data were well described by the mechanism-based model integrating three subpopulations (susceptible, intermediate and resistant). Compared with the susceptible subpopulation of mcr-1 -harbouring E. coli , the resistant subpopulation had an approximately 10-fold lower rate of killing due to polymyxin B treatment. Manipulating initial dose intensity of polymyxin B was not able to overcome plasmid-mediated resistance due to mcr-1 in E. coli . This reinforces the need to develop new combinatorial strategies to combat these highly resistant Gram-negative bacteria.

  14. Calculation and Optimization of ITER Upper VS Feeder Under an Electromagnetic Load

    Institute of Scientific and Technical Information of China (English)

    WANG Xianwei; XIE Fei; JIN Huan

    2014-01-01

    The upper vertical stability (VS) feeder is a part connected to the upper VS coil by a welding joint.The function of the feeder is to transfer current and coolant water to the VS coil.A giant electromagnetic force will be generated during normal operation by the current flowing in the VS coils,interacting with the external background field.The Lorentz force will induce Tresca stress in the feeder.The amplitudes of the magnetic field and Lorentz force along the conductor running direction have been calculated based on Maxwell's equations.To extract the Tresca stress in the feeder,a finite element model was created using the software ANSYS and an electromagnetic load was applied on the model.According to the analytical design,the stresses were classified and evaluated based on ASME.In order to reduce the Tresca stress,some optimization works have been done and the Tresca stress has had a significant reduction in the optimized model.This analytical work figured out the stress distribution in the feeder and checked the feasibility of the prototype design model.The ANSYS analysis results will provide a guidance for later improvement and fabrication.

  15. A Power Load Distribution Algorithm to Optimize Data Center Electrical Flow

    Directory of Open Access Journals (Sweden)

    Paulo Maciel

    2013-07-01

    Full Text Available Energy consumption is a matter of common concern in the world today. Research demonstrates that as a consequence of the constantly evolving and expanding field of information technology, data centers are now major consumers of electrical energy. Such high electrical energy consumption emphasizes the issues of sustainability and cost. Against this background, the present paper proposes a power load distribution algorithm (PLDA to optimize energy distribution of data center power infrastructures. The PLDA, which is based on the Ford-Fulkerson algorithm, is supported by an environment called ASTRO, capable of performing the integrated evaluation of dependability, cost and sustainability. More specifically, the PLDA optimizes the flow distribution of the energy flow model (EFM. EFMs are responsible for estimating sustainability and cost issues of data center infrastructures without crossing the restrictions of the power capacity that each device can provide (power system or extract (cooling system. Additionally, a case study is presented that analyzed seven data center power architectures. Significant results were observed, achieving a reduction in power consumption of up to 15.5%.

  16. Optimized Preparation of Levofloxacin-loaded Chitosan Nanoparticles by Ionotropic Gelation

    Science.gov (United States)

    Guan, J.; Cheng, P.; Huang, S. J.; Wu, J. M.; Li, Z. H.; You, X. D.; Hao, L. M.; Guo, Y.; Li, R. X.; Zhang, H.

    The present work investigates the feasibility of fabricating chitosan (CS)-levofloxacin (LOF) nanoparticles by ionotropic gelation technology. An orthogonal experiment was designed to optimize its preparing parameters and multi-index comprehensive weighed score analysis method was used to study the effects of various factors including concentration of CS, concentration of tripolyphosphate (TPP), mass ratio of CS to TPP, and mass ratio of CS to LOF on the properties of nanoparticles. The particles prepared under optimal condition of 2 mg/ml CS concentration, 2 mg/ml TPP concentration, 0.5:1 mass ratio of oil to water and 4:1 mass ratio of CS to TPP had 140 nm diameter, 0.95 span, 6.13% loading capacity (LC) and 24.91% encapsulation efficiency (EE). In vitro release profile showed that LOF released fast initially and then slowly with T90 occurring at 76.5 h. Future studies should focus on antibacterial and biocompatible properties in order to evaluate its potential as sustainable delivery system.

  17. Real-Time Vehicle Energy Management System Based on Optimized Distribution of Electrical Load Power

    Directory of Open Access Journals (Sweden)

    Yuefei Wang

    2016-10-01

    Full Text Available As a result of severe environmental pressure and stringent government regulations, refined energy management for vehicles has become inevitable. To improve vehicle fuel economy, this paper presents a bus-based energy management system for the electrical system of internal combustion engine vehicles. Both the model of an intelligent alternator and the model of a lead-acid battery are discussed. According to these models, the energy management for a vehicular electrical system is formulated as a global optimal control problem which aims to minimize fuel consumption. Pontryagin’s minimum principle is applied to solve the optimal control problem to realize a real-time control strategy for electrical energy management in vehicles. The control strategy can change the output of the intelligent alternator and the battery with the changes of electrical load and driving conditions in real-time. Experimental results demonstrate that, compared to the traditional open-loop control strategy, the proposed control strategy for vehicle energy management can effectively reduce fuel consumption and the fuel consumption per 100 km is decreased by approximately 1.7%.

  18. Expected treatment dose construction and adaptive inverse planning optimization: Implementation for offline head and neck cancer adaptive radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Yan Di; Liang Jian [Department of Radiation Oncology, Beaumont Health System, Royal Oak, Michigan 48073 (United States)

    2013-02-15

    Purpose: To construct expected treatment dose for adaptive inverse planning optimization, and evaluate it on head and neck (h and n) cancer adaptive treatment modification. Methods: Adaptive inverse planning engine was developed and integrated in our in-house adaptive treatment control system. The adaptive inverse planning engine includes an expected treatment dose constructed using the daily cone beam (CB) CT images in its objective and constrains. Feasibility of the adaptive inverse planning optimization was evaluated retrospectively using daily CBCT images obtained from the image guided IMRT treatment of 19 h and n cancer patients. Adaptive treatment modification strategies with respect to the time and the number of adaptive inverse planning optimization during the treatment course were evaluated using the cumulative treatment dose in organs of interest constructed using all daily CBCT images. Results: Expected treatment dose was constructed to include both the delivered dose, to date, and the estimated dose for the remaining treatment during the adaptive treatment course. It was used in treatment evaluation, as well as in constructing the objective and constraints for adaptive inverse planning optimization. The optimization engine is feasible to perform planning optimization based on preassigned treatment modification schedule. Compared to the conventional IMRT, the adaptive treatment for h and n cancer illustrated clear dose-volume improvement for all critical normal organs. The dose-volume reductions of right and left parotid glands, spine cord, brain stem and mandible were (17 {+-} 6)%, (14 {+-} 6)%, (11 {+-} 6)%, (12 {+-} 8)%, and (5 {+-} 3)% respectively with the single adaptive modification performed after the second treatment week; (24 {+-} 6)%, (22 {+-} 8)%, (21 {+-} 5)%, (19 {+-} 8)%, and (10 {+-} 6)% with three weekly modifications; and (28 {+-} 5)%, (25 {+-} 9)%, (26 {+-} 5)%, (24 {+-} 8)%, and (15 {+-} 9)% with five weekly modifications. Conclusions

  19. Green Synthesis of Silver Nanorods and Optimization of Its Therapeutic Cum Toxic Dose.

    Science.gov (United States)

    Suganya, T R; Devasena, T

    2015-12-01

    Germinated Fenugreek seeds are relatively rich in flavonoids and polyphenols than dry seeds. Therefore, germinated fenugreek seeds possess better pharmacological activities. We have used an aqueous extract of germinated fenugreek seeds to reduce silver nitrate into nanoscale silver rods. The silver nanorods showed Surface Plasmon peak at 450 nm as revealed from UV visible spectrum. Field Emission Scanning Electron Microscopy images revealed the monodispersity and rod morphology. X ray diffraction spectrum revealed the FCC crystal structure of nanorods. Fourier transform infrared spectroscopy peaks revealed the interaction between the phytochemicals of germinated fenugreek seeds and the silver nanorods. Characterization studies reveal the validation of the proposed green synthesis protocol to produce monodispersed silver nanorods with phytochemical capping. The phytosynthesized silver nanorods exhibited anticancer activity in skin cancer cell line, which may be due to its nanoscale dimension and the surface functionalization. For the first time, we have optimized the therapeutic cum toxic dose of phytostabilized silver nanorods using skin cancer cell model.

  20. Optimizing hyaluronidase dose and plasmid DNA delivery greatly improves gene electrotransfer efficiency in rat skeletal muscle

    DEFF Research Database (Denmark)

    Åkerström, Thorbjörn; Vedel, Kenneth; Needham Andersen, Josefine;

    2015-01-01

    delivery across the muscle by increasing the number of plasmid DNA injections further enhanced transfection efficiency whereas increasing plasmid dose from 0.2 to 1.6. μg/g b.w. or vehicle volume had no effect. The optimized protocol resulted in ~80% (CI95%: 79-84%) transfected muscle fibers......Transfection of rat skeletal muscle in vivo is a widely used research model. However, gene electrotransfer protocols have been developed for mice and yield variable results in rats. We investigated whether changes in hyaluronidase pre-treatment and plasmid DNA delivery can improve transfection...... with a homogenous distribution. We also show that transfection was stable over five weeks of regular exercise or inactivity. Our findings show that species-specific plasmid DNA delivery and hyaluronidase pre-treatment greatly improves transfection efficiency in rat skeletal muscle....

  1. After Proper Optimization of Carvedilol dose, do Different Child Classes of Liver Disease Differ in Terms of dose Tolerance and Response on a Chronic Basis?

    Science.gov (United States)

    Wani, Zeeshan A.; Baht, Riyaz A.; Bhadoria, Ajeet S.; Maiwall, Rakhi; Majeed, Yamin; Khan, Afaq A.; Zargar, Showkat A.; Shah, Mohd A.; Khan, Kaiser M.

    2015-01-01

    Background/Aims: Literature regarding safe doses of carvedilol is limited, and safe doses across different Child classes of chronic liver disease are not clear. Patients and Methods: A total of 102 consecutive cirrhotic patients with significant portal hypertension were included in this study. Hepatic venous pressure gradient was measured at baseline and 3 months after dose optimization. Results: A total of 102 patients (63 males, 39 females) with a mean age of 58.3 ± 6.6 years were included. Among these patients, 42.2% had Child Class A, 31.9% had Class B, and 26.6% had Child Class C liver disease. The mean baseline hepatic venous pressure gradient was 16.75 ± 2.12 mmHg, and after dose optimization and reassessment of hepatic venous pressure gradient at 3 months, the mean reduction in the hepatic venous pressure gradient was 5.5 ± 1.7 mmHg and 2.8 ± 1.6 mmHg among responders and nonresponders respectively. The mean dose of carvedilol was higher in nonresponders (19.2 ± 5.7 mg) than responders (18.75 ± 5.1 mg). However, this difference was not statistically significant (P > 0.05). The univariate analysis determined that the absence of adverse events, the absence of ascites, and low baseline cardiac output were significantly associated with chronic response, whereas, the etiology, Child class, variceal size (large vs small), and gender were not. On multivariate analysis, the absence of any adverse event was determined to be an independent predictor of chronic response (OR 11.3, 95% CI; 1.9–67.8). Conclusion: The proper optimization of the dose of carvedilol, when administered chronically, may enable carvedilol treatment to achieve a greater response with minimum side effects among different Child classes of liver disease. PMID:26458853

  2. Optimization in the relation between image quality and patient dose in head CT

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Diaz, M.; Paz-Viera, J.E., E-mail: mperez@uclv.edu.cu [Center for Studies on Eletronics and Info. Tech., Universidad Central ' Marta Abreu' , Santa Clara (Cuba); Carvalho Filho, A.E. [Universidade Estadual de Santa Cruz, Ilheus, BA (Brazil). Departamento de Ciencias Exatas e Tecnologicas; Andrade, M.E.A.; Khoury, H.J. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Energia Nuclear

    2013-08-15

    Thirty-two head CT scans were acquired employing an anthropomorphic phantom containing lesions in the posterior fossa, using 2 scanners: Siemens Sensation with 64 slices and Philips Brilliance with 6 slices. Parameters as tube current (mA), slice thickness (mm), collimation (mm), tube potential (kVp) and dynamic range were changed during studies, looking for the optimal acquisition/processing conditions which permit both good lesion detectability and the lowest dose. The CT air kerma index (mGy) was measured with a pencil ionization chamber. Image quality was analyzed by 5 radiologists using a 5 points-scale criteria (1=poor, 2=fair, 3=good, 4=very good, 5=excellent) and also using 5 figure of merit in the spatial and frequency domains: Contrast (C [%]), Contrast to Noise Ratio (CNR), Signal to Noise Ratio (SNR), Normalized Mean Square Error (NMSE) and Spectral Distance (SD). Objective and subjective results were correlated. We observed that doses could be reduced by up to 25% respect to the usual practice with both scanners, mainly reducing the mAs, without affecting lesion detection. As a result, we propose an optimized protocol for each scanner as follow: 250 mAs, 120 kVp and the collimation of 6 slices x 1.50 mm per rotation the same reconstructed slice thickness to detect the lesions in the posterior fossa with good image quality for the Philips Brilliance 6, while 150 mAs, 100 kVp, collimation of 30 x 1.2 mm and reconstructed slice thickness of 3.0 mm were needed with the Siemens Sensation 64. (author)

  3. Microfluidic approach for fast labeling optimization and dose-on-demand implementation

    Energy Technology Data Exchange (ETDEWEB)

    Pascali, Giancarlo, E-mail: pascali@ifc.cnr.i [Radiopharmacy Department, Institute of Clinical Physiology, Via Moruzzi 1, 56124 Pisa (Italy); Mazzone, Grazia [Radiopharmacy Department, Institute of Clinical Physiology, Via Moruzzi 1, 56124 Pisa (Italy); IUSS, Piazza Ghislieri, 27100 Pavia (Italy); Saccomanni, Giuseppe; Manera, Clementina [Dipartimento di Scienze Farmaceutiche, Universita di Pisa, Via Bonanno 6, 56126 Pisa (Italy); Salvadori, Piero A. [Radiopharmacy Department, Institute of Clinical Physiology, Via Moruzzi 1, 56124 Pisa (Italy)

    2010-07-15

    Introduction: The diffusion of PET as a pivotal molecular imaging modality has emphasized the need for new positron-emitting radiotracers to be used in diagnostic applications and research. Microfluidic represents an innovative approach, owing to its potential to increase radiochemical productivity in terms of yields, time reduction, precursor consumption and flexible experimental planning. Methods: We focused on fluorine-18 labeling and used a microfluidic platform to perform sequential reactions, by using the same batch of {sup 18}F-labeling solution on one or more substrates, during the same experimental session. A solid-phase extraction (SPE) workup procedure was also implemented in the system to provide a repeatable purification step. Results: We were able to quickly optimize the conditions for labeling of ethyl and propyl ditosylate and of a new cannabinoid type 2 (CB2) receptor agonist, CB41. In all substrates, we obtained good incorporation yields (60% to 85%) in short (<90 s) reaction times. Single dosages of the CB2 ligand were sequentially prepared, upon request, in satisfactory quantities and purity for small animal PET scanning. Conclusion: This work demonstrates the usefulness of a microfluidic-based system for a rapid optimization of temperature, flow rate of reactants and their relative ratio in the labeling of different precursors by using the same {sup 18}F-fluoride batch. This approach was used to obtain in sequence several injectable doses of a novel CB2 ligand, thus providing the proof of principle that microfluidic systems permit a dose-on-demand production of new radiotracers.

  4. Simultaneous Optimization of Tooth Flank Form of Involute Helical Gears in Terms of Both Vibration and Load Carrying Capacity

    Science.gov (United States)

    Komori, Masaharu; Kubo, Aizoh; Suzuki, Yoshitomo

    The alignment condition of automotive gears changes considerably during operation due to the deformation of shafts, bearings, and gear box by transmission of load. Under such conditions, the gears are required to satisfy not only reliability in strength and durability under maximum loading conditions, but also low vibrational characteristics under light loading conditions during the cruising of a car. In this report, the characteristics of the optimum tooth flank form of gears in terms of both vibration and load carrying capacity are clarified. The local optimum tooth flank form appears in each excitation valley, where the vibrational excitation is low and the actual contact ratio takes a specific value. The influence of the choice of different local optimum solutions on the vibrational performance of the optimized gears is investigated. The practical design algorithm for the optimum tooth flank form of a gear set in terms of both vibration and load carrying capacity is then proposed and its result is evaluated by field experience.

  5. Treatment planning of intensity modulated composite particle therapy with dose and linear energy transfer optimization

    Science.gov (United States)

    Inaniwa, Taku; Kanematsu, Nobuyuki; Noda, Koji; Kamada, Tadashi

    2017-06-01

    The biological effect of charged-particle beams depends on both dose and particle spectrum. As one of the physical quantities describing the particle spectrum of charged-particle beams, we considered the linear energy transfer (LET) throughout this study. We investigated a new therapeutic technique using two or more ion species in one treatment session, which we call an intensity modulated composite particle therapy (IMPACT), for optimizing the physical dose and dose-averaged LET distributions in a patient as its proof of principle. Protons and helium, carbon, and oxygen ions were considered as ion species for IMPACT. For three cubic targets of 4  ×  4  ×  4, 8  ×  8  ×  8, and 12  ×  12  ×  12 cm3, defined at the center of the water phantom of 20  ×  20  ×  20 cm3, we made IMPACT plans of two composite fields with opposing and orthogonal geometries. The prescribed dose to the target was fixed at 1 Gy, while the prescribed LET to the target was varied from 1 keV µm-1 to 120 keV µm-1 to investigate the range of LET valid for prescription. The minimum and maximum prescribed LETs, (L T_min, L T_max), by the opposing-field geometry, were (3 keV µm-1, 115 keV µm-1), (2 keV µm-1, 84 keV µm-1),and (2 keV µm-1, 66 keV µm-1), while those by the orthogonal-field geometry were (8 keV µm-1, 98 keV µm-1), (7 keV µm-1, 72 keV µm-1), and (8 keV µm-1, 57 keV µm-1) for the three targets, respectively. To show the proof of principle of IMPACT in a clinical situation, we made IMPACT plans for a prostate case. In accordance with the prescriptions, the LETs in prostate, planning target volume (PTV), and rectum could be adjusted at 80 keV µm-1, at 50 keV µm-1, and below 30 keV µm-1, respectively, while keeping the dose to the PTV at 2 Gy uniformly. IMPACT enables the optimization of the dose and the LET distributions in a patient, which will maximize the

  6. On the Optimization of the Doses of Chemical Fertilizers for Crops

    Science.gov (United States)

    Sala, Florin; Boldea, Marius

    2011-09-01

    The mono-factorial model, which gives the relation between the yield and the dose of chemical fertilizers, is based on the Mitscherlich function f1(x) = f1(0)+a1(1-e-11x). In addition to this function, we can consider f2(x) = f2(0)+a2 tanh(b2x), to be the basis for a new mathematical model, where tanh(b2x) represents the hyperbolic tangent. In the case of a bi-factorial model: f(x,y) = f(0,0)+a1 tanh(b1x)+a2 tanh(b2y)+a3 tanh(b1x)tanh(b2y) represents a generalization of the last relation. The constants that are involved in these functions are determined with the least squares method, by comparison with the experimental data. Taking into account both the market value of the products and the cost of fertilizers, we can find the optimal doses for maximizing certain economic indicators, such as revenue or profitability.

  7. Optimal use of β-blockers in high-risk hypertension: A guide to dosing equivalence

    Directory of Open Access Journals (Sweden)

    Janet B McGill

    2010-05-01

    Full Text Available Janet B McGillDepartment of Medicine, Washington University School of Medicine, St. Louis, Missouri, USAAbstract: Hypertension is the number one diagnosis made by primary care physicians, placing them in a unique position to prescribe the antihypertensive agent best suited to the individual patient. In individuals with diabetes mellitus, blood pressure (BP levels > 130/80 mmHg confer an even higher risk for cardiovascular and renal disease, and these patients will benefit from aggressive antihypertensive treatment using a combination of agents. β‑blockers are playing an increasingly important role in the management of hypertension in high-risk patients. β‑blockers are a heterogeneous class of agents, and this review presents the differences between β‑blockers and provides evidence-based protocols to assist in understanding dose equivalence in the selection of an optimal regimen in patients with complex needs. The clinical benefits provided by β‑blockers are only effective if patients adhere to medication treatment long term. β‑blockers with proven efficacy, once-daily dosing, and lower side effect profiles may become instrumental in the treatment of hypertensive diabetic and nondiabetic patients.Keywords: antihypertensive, blood pressure, atenolol, carvedilol, labetalol, metoprolol, nebivolol

  8. Optimal dose of contrast medium for depiction of hypervascular HCC on dynamic MDCT

    Energy Technology Data Exchange (ETDEWEB)

    Fujigai, Tetsuya, E-mail: tetuyafu2000@yahoo.co.jp [Department of Radiology, Kinki University School of Medicine, Osakasayama City, Osaka 589-8511 (Japan); Kumano, Seishi, E-mail: kumano@radiol.med.kindai.ac.jp [Department of Radiology, Kinki University School of Medicine, Osakasayama City, Osaka 589-8511 (Japan); Okada, Masahiro, E-mail: mokada@radiol.med.kindai.ac.jp [Department of Radiology, Kinki University School of Medicine, Osakasayama City, Osaka 589-8511 (Japan); Hyodo, Tomoko, E-mail: Hyoudo@radiol.med.kindai.ac.jp [Department of Radiology, Kinki University School of Medicine, Osakasayama City, Osaka 589-8511 (Japan); Imaoka, Izumi, E-mail: iizumi@med.kindai.ac.jp [Department of Radiology, Kinki University School of Medicine, Osakasayama City, Osaka 589-8511 (Japan); Yagyu, Yukinobu, E-mail: y-yagyu@med.kindai.ac.jp [Department of Radiology, Kinki University School of Medicine, Osakasayama City, Osaka 589-8511 (Japan); Ashikaga, Ryuichiro, E-mail: ryuman@med.kindai.ac.jp [Department of Radiology, Kinki University School of Medicine, Osakasayama City, Osaka 589-8511 (Japan); Ishii, Kazunari, E-mail: ishii@med.kindai.ac.jp [Department of Radiology, Kinki University School of Medicine, Osakasayama City, Osaka 589-8511 (Japan); Murakami, Takamichi, E-mail: murakami@med.kindai.ac.jp [Department of Radiology, Kinki University School of Medicine, Osakasayama City, Osaka 589-8511 (Japan)

    2012-11-15

    Purpose: The purpose of this study is to prospectively investigate the optimal dose of contrast medium for the depiction of hypervascular hepatocellular carcinoma (HCC) during the hepatic arterial phase (HAP), portal venous phase (PVP) and delayed phase (DP) of dynamic MDCT. Materials and methods: The study included 128 patients, out of these patients, 36 patients were found to have 56 hypervascular HCCs. Sixty-three patients were assigned to receive a dose of 525 mgI/kg with protocol A, and 62 received a dose of 630 mgI/kg with protocol B. Measurements of the attenuation values of the abdominal aorta, portal vein, hepatic vein, hepatic parenchyma and HCC during the HAP, PVP and DP were taken. Tumor-liver contrast (TLC) was calculated from the attenuation value of the hepatic parenchyma and HCC. Results: The aortic attenuation value with protocol B (351, 166, and 132 HU) was significantly higher than that with protocol A (313, 153, and 120 HU) during all the phases, (P < 0.01 for all phases). The hepatic enhancement from unenhanced baseline with protocol B (25.2, 63.6, 50.6 HU) was significantly higher than that with protocol A (20.2, 55.1 and 43.0 HU) during all the phases, (P < 0.01 for all phases). The TLC with protocol B (37.4, -11.8 and -13.6 HU) was significantly higher than that with protocol A (28.0, -9.8 and -12.1 HU) during HAP (P = 0.042). Conclusion: The administration of 630 mgI/kg of body weight depicts hypervascular HCC more clearly during HAP and shows sufficient hepatic enhancement of 50 HU during DP.

  9. Role of the parameters involved in the plan optimization based on the generalized equivalent uniform dose and radiobiological implications

    Science.gov (United States)

    Widesott, L.; Strigari, L.; Pressello, M. C.; Benassi, M.; Landoni, V.

    2008-03-01

    We investigated the role and the weight of the parameters involved in the intensity modulated radiation therapy (IMRT) optimization based on the generalized equivalent uniform dose (gEUD) method, for prostate and head-and-neck plans. We systematically varied the parameters (gEUDmax and weight) involved in the gEUD-based optimization of rectal wall and parotid glands. We found that the proper value of weight factor, still guaranteeing planning treatment volumes coverage, produced similar organs at risks dose-volume (DV) histograms for different gEUDmax with fixed a = 1. Most of all, we formulated a simple relation that links the reference gEUDmax and the associated weight factor. As secondary objective, we evaluated plans obtained with the gEUD-based optimization and ones based on DV criteria, using the normal tissue complication probability (NTCP) models. gEUD criteria seemed to improve sparing of rectum and parotid glands with respect to DV-based optimization: the mean dose, the V40 and V50 values to the rectal wall were decreased of about 10%, the mean dose to parotids decreased of about 20-30%. But more than the OARs sparing, we underlined the halving of the OARs optimization time with the implementation of the gEUD-based cost function. Using NTCP models we enhanced differences between the two optimization criteria for parotid glands, but no for rectum wall.

  10. Fluence map optimization (FMO) with dose-volume constraints in IMRT using the geometric distance sorting method

    Science.gov (United States)

    Lan, Yihua; Li, Cunhua; Ren, Haozheng; Zhang, Yong; Min, Zhifang

    2012-10-01

    A new heuristic algorithm based on the so-called geometric distance sorting technique is proposed for solving the fluence map optimization with dose-volume constraints which is one of the most essential tasks for inverse planning in IMRT. The framework of the proposed method is basically an iterative process which begins with a simple linear constrained quadratic optimization model without considering any dose-volume constraints, and then the dose constraints for the voxels violating the dose-volume constraints are gradually added into the quadratic optimization model step by step until all the dose-volume constraints are satisfied. In each iteration step, an interior point method is adopted to solve each new linear constrained quadratic programming. For choosing the proper candidate voxels for the current dose constraint adding, a so-called geometric distance defined in the transformed standard quadratic form of the fluence map optimization model was used to guide the selection of the voxels. The new geometric distance sorting technique can mostly reduce the unexpected increase of the objective function value caused inevitably by the constraint adding. It can be regarded as an upgrading to the traditional dose sorting technique. The geometry explanation for the proposed method is also given and a proposition is proved to support our heuristic idea. In addition, a smart constraint adding/deleting strategy is designed to ensure a stable iteration convergence. The new algorithm is tested on four cases including head-neck, a prostate, a lung and an oropharyngeal, and compared with the algorithm based on the traditional dose sorting technique. Experimental results showed that the proposed method is more suitable for guiding the selection of new constraints than the traditional dose sorting method, especially for the cases whose target regions are in non-convex shapes. It is a more efficient optimization technique to some extent for choosing constraints than the dose

  11. Analysis Of The Performance Of An Optimization Model For Time-Shiftable Electrical Load Scheduling Under Uncertainty

    Science.gov (United States)

    2016-12-01

    NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS ANALYSIS OF THE PERFORMANCE OF AN OPTIMIZATION MODEL FOR TIME-SHIFTABLE ELECTRICAL LOAD...REPORT TYPE AND DATES COVERED Master’s Thesis 01-04-2016 to 09-23-2016 4. TITLE AND SUBTITLE ANALYSIS OF THE PERFORMANCE OF AN OPTIMIZATIONMODEL FOR...INTENTIONALLY LEFT BLANK ii Approved for public release. Distribution is unlimited. ANALYSIS OF THE PERFORMANCE OF AN OPTIMIZATION MODEL FOR TIME-SHIFTABLE

  12. Combined MV + kV inverse treatment planning for optimal kV dose incorporation in IGRT

    Science.gov (United States)

    Grelewicz, Zachary; Wiersma, Rodney D.

    2014-04-01

    Despite the existence of real-time kV intra-fractional tumor tracking strategies for many years, clinical adoption has been held back by concern over the excess kV imaging dose cost to the patient when imaging in continuous fluoroscopic mode. This work aims to solve this problem by investigating, for the first time, the use of convex optimization tools to optimally integrate this excess kV imaging dose into the MV therapeutic dose in order to make real-time kV tracking clinically feasible. Phase space files modeling both a 6 MV treatment beam and a kV on-board-imaging beam of a commercial LINAC were generated with BEAMnrc, and used to generate dose influence matrices in DOSXYZnrc for ten previously treated lung cancer patients. The dose optimization problem for IMRT, formulated as a quadratic problem, was modified to include additional constraints as required for real-time kV intra-fractional tracking. An interior point optimizer was used to solve the modified optimization problem. It was found that when using large kV imaging apertures during fluoroscopic tracking, combined MV + kV optimization lead to a 0.5%-5.17% reduction in the total number of monitor units assigned to the MV beam due to inclusion of the kV dose over the ten patients. This was accompanied by a reduction of up to 42% of the excess kV dose compared to standard MV IMRT with kV tracking. For all kV field sizes considered, combined MV + kV optimization provided prescription dose to the treatment volume coverage equal to the no-imaging case, yet superior to standard MV IMRT with non-optimized kV fluoroscopic tracking. With combined MV + kV optimization, it is possible to quantify in a patient specific way the dosimetric effect of real-time imaging on the patient. Such information is necessary when substantial kV imaging is performed.

  13. Feasibility and robustness of dose painting by numbers in proton therapy with contour-driven plan optimization

    Energy Technology Data Exchange (ETDEWEB)

    Barragán, A. M., E-mail: ana.barragan@uclouvain.be; Differding, S.; Lee, J. A.; Sterpin, E. [Center of Molecular Imaging, Radiotherapy and Oncology, Institut de Recherche Expérimentale et Clinique, Université catholique de Louvain, Brussels B-1200 (Belgium); Janssens, G. [Ion Beam Applications S.A., Louvain-la-Neuve 1348 (Belgium)

    2015-04-15

    Purpose: To prove the ability of protons to reproduce a dose gradient that matches a dose painting by numbers (DPBN) prescription in the presence of setup and range errors, by using contours and structure-based optimization in a commercial treatment planning system. Methods: For two patients with head and neck cancer, voxel-by-voxel prescription to the target volume (GTV{sub PET}) was calculated from {sup 18}FDG-PET images and approximated with several discrete prescription subcontours. Treatments were planned with proton pencil beam scanning. In order to determine the optimal plan parameters to approach the DPBN prescription, the effects of the scanning pattern, number of fields, number of subcontours, and use of range shifter were separately tested on each patient. Different constant scanning grids (i.e., spot spacing = Δx = Δy = 3.5, 4, and 5 mm) and uniform energy layer separation [4 and 5 mm WED (water equivalent distance)] were analyzed versus a dynamic and automatic selection of the spots grid. The number of subcontours was increased from 3 to 11 while the number of beams was set to 3, 5, or 7. Conventional PTV-based and robust clinical target volumes (CTV)-based optimization strategies were considered and their robustness against range and setup errors assessed. Because of the nonuniform prescription, ensuring robustness for coverage of GTV{sub PET} inevitably leads to overdosing, which was compared for both optimization schemes. Results: The optimal number of subcontours ranged from 5 to 7 for both patients. All considered scanning grids achieved accurate dose painting (1% average difference between the prescribed and planned doses). PTV-based plans led to nonrobust target coverage while robust-optimized plans improved it considerably (differences between worst-case CTV dose and the clinical constraint was up to 3 Gy for PTV-based plans and did not exceed 1 Gy for robust CTV-based plans). Also, only 15% of the points in the GTV{sub PET} (worst case) were

  14. Determining optimal dosing regimen of oral administration of dicloxacillin using Monte Carlo simulation

    Directory of Open Access Journals (Sweden)

    Yu W

    2017-06-01

    Full Text Available Wei Yu,1,2,* Jinru Ji,1,* Tingting Xiao,1 Chaoqun Ying,1 Jiaheng Fang,3 Ping Shen,1 Yonghong Xiao1 1State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, 2Department of Infectious Diseases, Zhejiang Provincial People’s Hospital, 3Department of Gastroenterology, Hang Zhou Normal University Affiliated Hospital, Hangzhou, People’s Republic of China *These authors contributed equally to this work Background: Dicloxacillin, a semisynthetic isoxazolyl penicillin, exhibits antimicrobial activity against a wide variety of Gram-positive bacteria, as well as stability against penicillinases and low level of toxicity. The objective of this study was to obtain optimal dosing regimen of oral administration of dicloxacillin by analyzing the pharmacokinetic (PK index in healthy volunteers and in vitro antibacterial activity by using Monte Carlo simulation. Materials and methods: A total of 867 clinical isolates from community-onset infections were collected from 31 secondary hospitals in People’s Republic of China. The minimum inhibitory concentration (MIC values of dicloxacillin were determined by the agar dilution method. Based on the MICs and the PK parameters of different dosage regimens, Monte Carlo simulation was performed to simulate the PK/pharmacodynamic indices of 250 mg once-daily (qd, 500 mg qd, 1,000 mg qd, 2,000 mg qd, 250 mg every 6 hours (q6h, and 500 mg q6h, respectively. The probability of target attainment was estimated at each MIC value, and the cumulative fraction of response (CFR was calculated to evaluate the efficacy of these regimens. Results: Dicloxacillin showed poor antibacterial activity against Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae. Resistance to dicloxacillin was observed in 7.5% of coagulase

  15. Optimal image reconstruction for detection and characterization of small pulmonary nodules during low-dose CT

    Energy Technology Data Exchange (ETDEWEB)

    Hashemi, SayedMasoud; Cobbold, Richard S.C. [University of Toronto, Institute of Biomaterial and Biomedical Engineering, Toronto, ON (Canada); Mehrez, Hatem [Toshiba of Canada Ltd, Markham, ON (Canada); Paul, Narinder S. [University Health Network, Medical Imaging, Toronto General Hospital, Toronto, ON (Canada)

    2014-06-15

    To optimize the slice thickness/overlap parameters for image reconstruction and to study the effect of iterative reconstruction (IR) on detectability and characterization of small non-calcified pulmonary nodules during low-dose thoracic CT. Data was obtained from computer simulations, phantom, and patient CTs. Simulations and phantom CTs were performed with 9 nodules (5, 8, and 10 mm with 100, -630, and -800 HU). Patient data were based on 11 ground glass opacities (GGO) and 9 solid nodules. For each analysis the nodules were reconstructed with filtered back projection and IR algorithms using 10 different combinations of slice thickness/overlap (0.5-5 mm). The attenuation (CT) and the contrast to noise ratio (CNR) were measured. Spearman's coefficient was used to correlate the error in CT measurements and slice thickness. Paired Student's t test was used to measure the significance of the errors. CNR measurements: CNR increases with increasing slice thickness/overlap for large nodules and peaks at 4.0/2.0 mm for smaller ones. Use of IR increases the CNR of GGOs by 60 %. CT measurements: Increasing slice thickness/overlap above 3.0/1.5 mm results in decreased CT measurement accuracy. Optimal detection of small pulmonary nodules requires slice thickness/overlap of 4.0/2.0 mm. Slice thickness/overlap of 2.0/2.0 mm is required for optimal nodule characterization. IR improves conspicuity of small ground glass nodules through a significant increase in nodule CNR. (orig.)

  16. Reliability-oriented multi-objective optimal decision-making approach for uncertainty-based watershed load reduction

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Feifei [College of Environmental Science and Engineering, Key Laboratory of Water and Sediment Sciences (MOE), Peking University, Beijing 100871 (China); Liu, Yong, E-mail: yongliu@pku.edu.cn [College of Environmental Science and Engineering, Key Laboratory of Water and Sediment Sciences (MOE), Peking University, Beijing 100871 (China); Institute of Water Sciences, Peking University, Beijing 100871 (China); Su, Han [College of Environmental Science and Engineering, Key Laboratory of Water and Sediment Sciences (MOE), Peking University, Beijing 100871 (China); Zou, Rui [Tetra Tech, Inc., 10306 Eaton Place, Ste 340, Fairfax, VA 22030 (United States); Yunnan Key Laboratory of Pollution Process and Management of Plateau Lake-Watershed, Kunming 650034 (China); Guo, Huaicheng [College of Environmental Science and Engineering, Key Laboratory of Water and Sediment Sciences (MOE), Peking University, Beijing 100871 (China)

    2015-05-15

    Water quality management and load reduction are subject to inherent uncertainties in watershed systems and competing decision objectives. Therefore, optimal decision-making modeling in watershed load reduction is suffering due to the following challenges: (a) it is difficult to obtain absolutely “optimal” solutions, and (b) decision schemes may be vulnerable to failure. The probability that solutions are feasible under uncertainties is defined as reliability. A reliability-oriented multi-objective (ROMO) decision-making approach was proposed in this study for optimal decision making with stochastic parameters and multiple decision reliability objectives. Lake Dianchi, one of the three most eutrophic lakes in China, was examined as a case study for optimal watershed nutrient load reduction to restore lake water quality. This study aimed to maximize reliability levels from considerations of cost and load reductions. The Pareto solutions of the ROMO optimization model were generated with the multi-objective evolutionary algorithm, demonstrating schemes representing different biases towards reliability. The Pareto fronts of six maximum allowable emission (MAE) scenarios were obtained, which indicated that decisions may be unreliable under unpractical load reduction requirements. A decision scheme identification process was conducted using the back propagation neural network (BPNN) method to provide a shortcut for identifying schemes at specific reliability levels for decision makers. The model results indicated that the ROMO approach can offer decision makers great insights into reliability tradeoffs and can thus help them to avoid ineffective decisions. - Highlights: • Reliability-oriented multi-objective (ROMO) optimal decision approach was proposed. • The approach can avoid specifying reliability levels prior to optimization modeling. • Multiple reliability objectives can be systematically balanced using Pareto fronts. • Neural network model was used to

  17. Optimal dose of intravenous oxycodone for attenuating hemodynamic changes after endotracheal intubation in healthy patients

    Science.gov (United States)

    Park, Yong-Hee; Lee, Seung-Hyuk; Lee, Oh Haeng; Kang, Hyun; Shin, Hwa-Yong; Baek, Chong-Wha; Jung, Yong Hun; Woo, Young Cheol

    2017-01-01

    Abstract Background: Intravenous oxycodone has been used as an adjunct to anesthetic agents. This study aimed to assess the optimal dose of intravenous oxycodone for the attenuation of the hemodynamic responses to laryngoscopy and endotracheal intubation. Methods: A prospective, randomized, double-blind study was conducted. Ninety-five patients were randomly divided into 5 groups based on the oxycodone dose: 0, 0.05, 0.1, 0.15, 0.2 mg/kg. After administering the assigned dose of intravenous oxycodone, anesthesia was induced with thiopental. Heart rate (HR) and blood pressure (BP) were measured at baseline, before intubation, and 1, 2, and 3 minutes after intubation. The percentage increase of BP was calculated as (highest BP after intubation − baseline BP)/baseline BP × 100 (%). The percentage increase of HR was calculated in same formula as above. Hypertension was defined as a 15% increase of systolic BP from baseline, and probit analysis was conducted. Results: Hemodynamic data from 86 patients were analyzed. The percentage increase of mean arterial pressure after intubation in groups 0.05, 0.1, 0.15, and 0.2 was significantly different from that in the control (P < 0.001). For HR, the percentage increase was lower than control group when oxycodone was same or more than 0.1 mg/kg (P < 0.05). Using probit analysis, the 95% effective dose (ED95) for preventing hypertension was 0.159 mg/kg (95% confidence interval [CI], 0.122–0.243). In addition, ED50 was 0.020 mg/kg (95% CI, −0.037 to 0.049). However, oxycodone was not effective for maintaining the HR in our study dosage. There were no significant differences in the incidence of hypotension during induction between groups. Conclusions: Using 0.1 mg/kg of intravenous oxycodone is sufficient to attenuate the increase of BP and HR during induction period in healthy patients. The ED95, which was 0.159 mg/kg, can be useful to adjust the dosage of IV oxycodone for maintain stable BP

  18. Formulation Optimization of Rosuvastatin Calcium-Loaded Solid Lipid Nanoparticles by 32 Full-Factorial Design

    Directory of Open Access Journals (Sweden)

    Kruti A. Dhoranwala

    2015-12-01

    Full Text Available The present investigation was aimed at developing Rosuvastatin Calcium loaded solid lipid nanoparticles (SLNs. The SLNs were prepared using high pressure homogenization technique. Glyceryl monostearate (GMS and Poloxamer 188 were employed as lipid carrier and surfactant respectively. A two factor, three level (32 full factorial design was applied to study the effect of independent variables i.e. amount of GMS (X1 and amount of Poloxamer 188 (X2 on dependent variables i.e. Particle size (Y1 and % entrapment efficiency (Y2. Particles size, % entrapment efficiency (%EE, zeta potential, drug content, in vitro drug release and particles morphology were evaluated for SLNs. Contour plots and response surface plots showed visual representation of relationship between the experimental responses (dependent variables and the set of input (independent variables. The adequacy of the regression model was verified by a check point analysis. The optimized batch (B10 contained 2.2 gm of GMS and 1% of Poloxamer 188. Batch B 10 exhibited mean particle size of 529.6 nm ± 6.36 nm; polydispersity index (PDI of 0.306 ± 0.042; zeta potential of -31.88 mV ± (-2.50 mV and %EE of 48.90% ± 1.72%. The drug release experiments exhibited an initial rapid release followed by sustained release extended upto 36 h. Differential scanning calorimetry (DSC studies showed that there was no chemical interaction between drug (Rosuvastatin Calcium and lipid (GMS whereas scanning electron microscopy (SEM studies indicated that Rosuvastatin Calcium loaded SLNs are spherical, discrete and homogenous. Accelerated stability studies showed that there was no significant change occurring in the responses after storage for a total period of 3 months.

  19. Hippocampal dose from stereotactic radiosurgery for 4 to 10 brain metastases: Risk factors, feasibility of dose reduction via re-optimization, and patient outcomes.

    Science.gov (United States)

    Birer, Samuel R; Olson, Adam C; Adamson, Justus; Hood, Rodney; Susen, Matthew; Kim, Grace; Salama, Joseph K; Kirkpatrick, John P

    2017-07-28

    This study aimed to report hippocampal dose from single-fraction stereotactic radiosurgery (SRS) for 4 to 10 brain metastases and determine feasibility of hippocampal-sparing SRS. Patients with 4 to 10 brain metastases receiving single-isocenter, multi-target single-fraction SRS were identified. Hippocampi were contoured using the Radiation Therapy Oncology Group (RTOG) 0933 atlas. RTOG 0933 dose constraints were converted to a biologically effective dose using an alpha/beta of 2 (D100 421 cGy, Dmax 665 cGy). Number of metastases, total target volume, prescribed dose, and distance of nearest metastasis (dmin) were analyzed as risk factors for exceeding hippocampal constraints. If hippocampi exceeded constraints, the SRS plan was re-optimized. Key dosimetric parameters were compared between original and re-optimized plans. To determine if a single target can exceed constraints, all targets but the closest metastasis were removed from the plan, and dosimetry was compared. Forty plans were identified. Fifteen hippocampi (19%) exceeded constraints in 12 SRS plans. Hippocampal sparing was achieved in 10 of 12 replanned cases (83%). Risk factors associated with exceeding hippocampal constraints were decreasing dmin (24.0 vs 8.0 mm, p = 0.002; odds ratio [OR] 1.14, 95% confidence interval [CI] 1.04 to 1.26) and total target volume (5.46 cm(3)vs 1.98 cm(3), p = 0.03; OR 1.14, 95% CI 1.00 to 1.32). There was no difference in exceeding constraints for 4 to 5 vs 6 to 10 metastases (27% vs 21%, p = 0.409) or prescribed dose (18 Gy, p = 0.58). For re-optimized plans, there were no significant differences in planning target volume (PTV) coverage (99.6% vs 99.0%, p = 0.17) or conformality index (1.47 vs 1.4, p = 0.78). Six (50%) plans exceeded constraints with a single target. A substantial minority of hippocampi receive high radiation dose from SRS for 4 to 10 brain metastases. Decreasing distance of the closest metastasis and total target volume

  20. HYBRID GREY WOLF OPTIMIZATION-PATTERN SEARCH (hGWO-PS OPTIMIZED 2DOF-PID CONTROLLERS FOR LOAD FREQUENCY CONTROL (LFC IN INTERCONNECTED THERMAL POWER PLANTS

    Directory of Open Access Journals (Sweden)

    V Soni

    2016-04-01

    Full Text Available The combination of Grey Wolf Optimization and Pattern Search Technique (hGWO-PS has been introduced to optimize the parameters of two Degree of Freedom Proportional-Integral-Derivative Controller (2DOF-PID for controlling the load frequency in Automatic Generation Control (AGC for interconnected power system. The interconnected two area power system of non-reheat thermal power plants consisting of 2DOF-PID controller in each area has been considered for design and analysis. Firstly, the proposed approach has been implemented in the aforementioned standard test system and thereafter, the robustness of the system consisting 2DOF-PID controller optimized by proposed technique has been estimated using the sensitivity analysis for the same. The robustness of the system consisting of 2DOF-PID controller optimized by proposed scheme is examined by varying the parameters of standard test system, loading conditions during operation, size and location of the disturbances. The performance of the 2DOF-PID controller optimized by proposed approach has also been compared with recently published approaches in the literature. The simulation results show that the proposed hGWOPS optimized 2DOF-PID controller shows far better performance than recently published approaches in the literature in terms of dynamic response. The simulation results also show that system performances hardly change when the operating load condition and system parameters are changed by ±50% from their nominal values, i.e. the proposed controllers are quite robust for a wide range of the system parameters and operating load conditions from their nominal values.

  1. An open-source genetic algorithm for determining optimal seed distributions for low-dose-rate prostate brachytherapy.

    Science.gov (United States)

    McGeachy, P; Madamesila, J; Beauchamp, A; Khan, R

    2015-01-01

    An open source optimizer that generates seed distributions for low-dose-rate prostate brachytherapy was designed, tested, and validated. The optimizer was a simple genetic algorithm (SGA) that, given a set of prostate and urethra contours, determines the optimal seed distribution in terms of coverage of the prostate with the prescribed dose while avoiding hotspots within the urethra. The algorithm was validated in a retrospective study on 45 previously contoured low-dose-rate prostate brachytherapy patients. Dosimetric indices were evaluated to ensure solutions adhered to clinical standards. The SGA performance was further benchmarked by comparing solutions obtained from a commercial optimizer (inverse planning simulated annealing [IPSA]) with the same cohort of 45 patients. Clinically acceptable target coverage by the prescribed dose (V100) was obtained for both SGA and IPSA, with a mean ± standard deviation of 98 ± 2% and 99.5 ± 0.5%, respectively. For the prostate D90, SGA and IPSA yielded 177 ± 8 Gy and 186 ± 7 Gy, respectively, which were both clinically acceptable. Both algorithms yielded reasonable dose to the rectum, with V100 open source SGA was validated that provides a research tool for the brachytherapy community. Copyright © 2015 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  2. Techniques and tactics for optimizing CT dose in adults and children: state of the art and future advances.

    Science.gov (United States)

    Lambert, Jack; MacKenzie, John D; Cody, Dianna D; Gould, Robert

    2014-03-01

    With growing concern over radiation exposure from CT, dose reduction and optimization have become important considerations. Many protocol factors and CT technologies influence this dose reduction effort, and as such, users should maintain a working knowledge of developments in the field. Individual patient factors and scanner-specific details also require care and expertise, which are vital to the success of any dose reduction effort. The authors review the content of the Virtual Symposium on Radiation Safety in Computed Tomography (University of California Dose Optimization and Standardization Endeavor), specifically that pertaining to the more practical aspects of dose optimization. These range from prescan tips to postscan factors, as well as protocol definition itself. Topics discussed include localizer radiograph acquisition, tube current modulation, reconstruction methods, and pediatric considerations, with the content biased toward a CT technologist or protocol manager. Near-term innovations, including new iterative reconstruction methods, tube potential modulation, and dual-energy CT, are presented, and their capability for dose reduction is briefly discussed. Copyright © 2014 American College of Radiology. Published by Elsevier Inc. All rights reserved.

  3. A Simultaneous Biogeography based Optimal Placement of DG Units and Capacitor Banks in Distribution Systems with Nonlinear Loads

    Science.gov (United States)

    Sadeghi, Hassan; Ghaffarzadeh, Navid

    2016-09-01

    This paper uses a new algorithm namely biogeography based optimization (BBO) intended for the simultaneous placement of the distributed generation (DG) units and the capacitor banks in the distribution network. The procedure of optimization has been conducted in the presence of nonlinear loads (a cause of harmonic injection). The purpose of simultaneous optimal placement of the DG and the capacitor is the reduction of active and reactive losses. The difference in the values of loss reduction at different levels of the load have been included in the objective function and the considered objective function includes the constraints of voltage, size and the number of DG units and capacitor banks and the allowable range of the total harmonic distortion (THD) of the total voltage in accordance with the IEEE 519 standards. In this paper the placement has been performed on two load types ie constant and mixed power, moreover the effects of load models on the results and the effects of optimal placement on reduction of the THD levels have also been analyzed. The mentioned cases have been studied on a 33 bus radial distribution system.

  4. Dose optimization in adult patients exams in a computerized tomography service; Otimizacao de dose em exames de pacientes adultos em um servico de tomografia computadorizada

    Energy Technology Data Exchange (ETDEWEB)

    Pimentel, Juliana; Finatto, Jerusa D.; Silva, Ana Maria Marques da, E-mail: ana.marques@pucrs.br [Pontificia Universidade Catolica do Rio Grande do Sul (PUCRS), Porto Alegre, RS (Brazil); Froner, Ana Paula P. [CDI Tomografia e Ressonancia Magnetica, Porto Alegre, RS (Brazil)

    2013-08-15

    This paper presents a study of dose optimization in computed tomography X-ray of skull, chest and abdomen of adult patients, performed in a diagnostic imaging service in a large hospital. Images of a simulated dose phantom were acquired and the kVp, mAs, pitch, thickness and CTDI{sub vol} were collected directly from the equipment. Using the PACS system, regions of interest were delineated, where the mean and standard deviation of CT numbers for each protocol were been calculated. The optimization took into account the maintenance of the CT number and noise from images acquired with clinical protocols. It was observed that the protocols used in the service, in general, exhibit a low dose, despite the great variability among the different professional shifts. In examinations of the chest, skull and abdomen, changes in the values of mAs and pitch were suggested, allowing dose reductions (60%, 17% and 19%, respectively), without compromising the image diagnostic quality. (author)

  5. Low radiation dose protocol in cardiac CT with 100 kVp: usefulness of display preset optimization.

    Science.gov (United States)

    Nakaura, Takeshi; Kidoh, Masafumi; Sakaino, Naritsugu; Nakamura, Shota; Nozaki, Toshimitsu; Izumi, Akari; Harada, Kazunori; Yamashita, Yasuyuki

    2013-08-01

    To evaluate the radiation dose and image quality of 100 kVp cardiac CT, and the effects of display setting optimization. We randomly assigned 100 patients undergoing cardiac CT to one of following two protocols. Fifty patients underwent our conventional protocol with 120 kVp, and the other 50 patients underwent our low radiation dose protocol with 100 kVp. We compared effective dose (ED); CT number, image noise, and contrast noise ratio (CNR) of ascending aorta at 120 and 100 kVp protocol. We also performed quantitative analysis and qualitative analysis for bitmap image of 120, 100 kVp, and display preset optimization for 100 kVp images. The estimated ED was 48 % lower with the 100 kVp protocol than the 120 kVp protocol (2.8 vs. 5.5 mSv, p protocol (18.5 ± 3.6 vs. 18.6 ± 3.8, p = 0.84). Display preset optimization significantly improved image quality of 100 kVp cardiac CT, and there is no significant difference in qualitative analysis and quantitative analysis between 100 kVp scan with optimized display preset and 120 kVp scan (p > 0.05). The 100 kVp scanning with optimized display preset offers almost same image quality at cardiac CT of thin adults under 48 % decreased radiation dose.

  6. Improving the content uniformity of a low-dose tablet formulation through roller compaction optimization.

    Science.gov (United States)

    am Ende, Mary T; Moses, Sara K; Carella, Anthony J; Gadkari, Rashmi A; Graul, Timothy W; Otano, Angel L; Timpano, Robert J

    2007-01-01

    In this investigation, the potency distribution of a low-dose drug in a granulation was optimized through a two-part study using statistically designed experiments. The purpose of this investigation was to minimize the segregation potential by improving content uniformity across the granule particle size distribution, thereby improving content uniformity in the tablet. Initial operating parameters on the Gerteis 3-W-Polygran 250/100/3 Roller Compactor resulted in a U-shaped potency function (potency vs. granule particle size) with superpotent fines and large granules. The roller compaction optimization study was carried out in two parts. Study I used a full factorial design with roll force (RF) and average gap width (GW) as independent variables and Study II used a D-optimal response surface design with four factors: RF, GW, granulating sieve size (SS), and granulator speed (GS). The planned response variables for Study I were bypass weight % and potency of bypass. Response variables for Study II included mean granulation potency with % relative standard deviation (% RSD), granulation particle size, sieve cut potency % RSD, tablet potency with % RSD, compression force at 7 kP crushing strength, and friability of 7-kP tablets. A constraint on GW was determined in Study I by statistical analysis. Bypass and observations of ribbon splitting were minimized when GW was less than 2.6 mm. In Study II, granulation potency, granulation uniformity, and sieve cut uniformity were optimized when the SS was 0.8 mm. Higher RF during dry granulation produced better sieve cut uniformity and tablets with improved uniformity throughout the run, as measured by stratified tablet samples taken during compression and assayed for potency. The recommended optimum roller compaction and milling operating parameters that simultaneously met all constraints were RF = 9 kN, GW = 2.3 mm, SS = 0.8 mm, and GS = 50 rpm. These parameters became the operating parameter set points during a model

  7. TU-G-204-04: A Unified Strategy for Bi-Factorial Optimization of Radiation Dose and Contrast Dose in CT Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Sahbaee, P; Zhang, Y; Solomon, J; Becchetti, M; Segars, P; Samei, E [Duke University Medical Center, Durham, NC (United States)

    2015-06-15

    Purpose: To substantiate the interdependency of contrast dose, radiation dose, and image quality in CT towards the patient- specific optimization of the imaging protocols Methods: The study deployed two phantom platforms. A variable sized (12, 18, 23, 30, 37 cm) phantom (Mercury-3.0) containing an iodinated insert (8.5 mgI/ml) was imaged on a representative CT scanner at multiple CTDI values (0.7–22.6 mGy). The contrast and noise were measured from the reconstructed images for each phantom diameter. Linearly related to iodine-concentration, contrast-to-noise ratio (CNR), were calculated for 16 iodine-concentration levels (0–8.5 mgI/ml). The analysis was extended to a recently developed suit of 58 virtual human models (5D XCAT) with added contrast dynamics. Emulating a contrast-enhanced abdominal image procedure and targeting a peak-enhancement in aorta, each XCAT phantom was “imaged” using a simulation platform (CatSim, GE). 3D surfaces for each patient/size established the relationship between iodine-concentration, dose, and CNR. The ratios of change in iodine-concentration versus dose (IDR) to yield a constant change in CNR were calculated for each patient size. Results: Mercury phantom results show the image-quality size- dependence on CTDI and IC levels. For desired image-quality values, the iso-contour-lines reflect the trade off between contrast-material and radiation doses. For a fixed iodine-concentration (4 mgI/mL), the IDR values for low (1.4 mGy) and high (11.5 mGy) dose levels were 1.02, 1.07, 1.19, 1.65, 1.54, and 3.14, 3.12, 3.52, 3.76, 4.06, respectively across five sizes. The simulation data from XCAT models confirmed the empirical results from Mercury phantom. Conclusion: The iodine-concentration, image quality, and radiation dose are interdependent. The understanding of the relationships between iodine-concentration, image quality, and radiation dose will allow for a more comprehensive optimization of CT imaging devices and techniques

  8. Comparative evaluation of two different loading doses of dexmedetomidine with midazolam-fentanyl for sedation in vitreoretinal surgery under peribulbar anaesthesia

    OpenAIRE

    2016-01-01

    Background and Aims: Midazolam-fentanyl (MDZ:FEN) combination has been routinely used for intravenous sedation in ophthalmic surgeries. Dexmedetomidine (DEX), a recent α2 adrenoreceptor agonist indicated for sedation for ophthalmic use at a loading dose of 0.5 μg/kg over 10 min, can cause deeper plane of sedation and surgeon dissatisfaction. Therefore, we proposed to evaluate the efficacy and safety of two different loading doses of DEX. Methods: In a prospective study, 60 patients aged 50-70...

  9. Accessibility of Enzymatically Delignified Bambusa bambos for Efficient Hydrolysis at Minimum Cellulase Loading: An Optimization Study

    Directory of Open Access Journals (Sweden)

    Arindam Kuila

    2011-01-01

    Full Text Available In the present investigation, Bambusa bambos was used for optimization of enzymatic pretreatment and saccharification. Maximum enzymatic delignification achieved was 84%, after 8 h of incubation time. Highest reducing sugar yield from enzyme-pretreated Bambusa bambos was 818.01 mg/g dry substrate after 8 h of incubation time at a low cellulase loading (endoglucanase, β-glucosidase, exoglucanase, and xylanase were 1.63 IU/mL, 1.28 IU/mL, 0.08 IU/mL, and 47.93 IU/mL, respectively. Enzyme-treated substrate of Bambusa bambos was characterized by analytical techniques such as Fourier transformed infrared spectroscopy (FTIR, X-ray diffraction (XRD, and scanning electron microscopy (SEM. The FTIR spectrum showed that the absorption peaks of several functional groups were decreased after enzymatic pretreatment. XRD analysis indicated that cellulose crystallinity of enzyme-treated samples was increased due to the removal of amorphous lignin and hemicelluloses. SEM image showed that surface structure of Bambusa bambos was distorted after enzymatic pretreatment.

  10. SU-C-BRB-02: Symmetric and Asymmetric MLC Based Lung Shielding and Dose Optimization During Translating Bed TBI

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, S; Kakakhel, MB [Pakistan Institute of Engineering & Applied Sciences (PIEAS), Islamabad (Pakistan); Ahmed, SBS; Hussain, A [Aga Khan University Hospital (AKUH), Karachi (Pakistan)

    2015-06-15

    Purpose: The primary aim was to introduce a dose optimization method for translating bed total body irradiation technique that ensures lung shielding dynamically. Symmetric and asymmetric dynamic MLC apertures were employed for this purpose. Methods: The MLC aperture sizes were defined based on the radiological depth values along the divergent ray lines passing through the individual CT slices. Based on these RD values, asymmetrically shaped MLC apertures were defined every 9 mm of the phantom in superior-inferior direction. Individual MLC files were created with MATLAB™ and were imported into Eclipse™ treatment planning system for dose calculations. Lungs can be shielded to an optimum level by reducing the MLC aperture width over the lungs. The process was repeated with symmetrically shaped apertures. Results: Dose-volume histogram (DVH) analysis shows that the asymmetric MLC based technique provides better dose coverage to the body and optimum shielding of the lungs compared to symmetrically shaped beam apertures. Midline dose homogeneity is within ±3% with asymmetric MLC apertures whereas it remains within ±4.5% with symmetric ones (except head region where it drops down to −7%). The substantial over and under dosage of ±5% at tissue interfaces has been reduced to ±2% with asymmetric MLC technique. Lungs dose can be reduced to any desired limit. In this experiment lungs dose was reduced to 80% of the prescribed dose, as was desired. Conclusion: The novel asymmetric MLC based technique assures optimum shielding of OARs (e.g. lungs) and better 3-D dose homogeneity and body-dose coverage in comparison with the symmetric MLC aperture optimization. The authors acknowledge the financial and infrastructural support provided by Pakistan Institute of Engineering & Applied Sciences (PIEAS), Islamabad and Aga Khan University Hospital (AKUH), Karachi during the course of this research project. Authors have no conflict of interest with any national / international

  11. Optimization and evaluation of a thermoresponsive ophthalmic in situ gel containing curcumin-loaded albumin nanoparticles

    Directory of Open Access Journals (Sweden)

    Lou J

    2014-05-01

    Full Text Available Jie Lou,1 Wenjing Hu,2 Rui Tian,3 Hua Zhang,1 Yuntao Jia,4 Jingqing Zhang,1 Liangke Zhang11Chongqing Key Laboratory of Biochemistry and Molecular Pharmacology, School of Pharmacy, Chongqing Medical University, Chongqing, People’s Republic of China; 2Chongqing Xijiao Hospital, Chongqing, People’s Republic of China; 3The Experimental Teaching Centre, Chongqing Medical University, Chongqing, People’s Republic of China; 4Department of Pharmacy, Children’s Hospital of Chongqing Medical University, Chongqing, People’s Republic of ChinaAbstract: This study aimed to optimize and evaluate a thermoresponsive ophthalmic in situ gel containing curcumin-loaded albumin nanoparticles (Cur-BSA-NPs-Gel. Albumin nanoparticles were prepared via a desolvation method, and the gels were prepared via a cold method. The central composite design and response surface method was used to evaluate the effects of varying Pluronic® F127 and Pluronic® F68 concentrations on the sol–gel transition temperature, which is an indicator of optimum formulations. The optimized formulation was a free-flowing liquid below 30.9°C that transformed into a semi-solid gel above 34.2°C after dilution with simulated tear fluid. Results of the in vitro release and erosion behavior study indicated that Cur-BSA-NPs-Gel achieved superior sustained-release effects and that incorporation of albumin nanoparticles exerted minimal effects on the gel structure. In addition, in vivo ophthalmic experiments employing Cur-BSA-NPs-Gel were subsequently performed in rabbits. In vivo eye irritation results showed that Cur-BSA-NPs-Gel might be considered safe for ophthalmic drug delivery. The in vivo study also revealed that the formulation could significantly increase curcumin bioavailability in the aqueous humor. In conclusion, the optimized in situ gel formulation developed in this work has significant potential for ocular application.Keywords: diabetic retinopathy, sustained release

  12. Organ sample generator for expected treatment dose construction and adaptive inverse planning optimization

    Energy Technology Data Exchange (ETDEWEB)

    Nie Xiaobo; Liang Jian; Yan Di [Department of Radiation Oncology, Beaumont Health System, Royal Oak, Michigan 48073 (United States)

    2012-12-15

    Purpose: To create an organ sample generator (OSG) for expected treatment dose construction and adaptive inverse planning optimization. The OSG generates random samples of organs of interest from a distribution obeying the patient specific organ variation probability density function (PDF) during the course of adaptive radiotherapy. Methods: Principle component analysis (PCA) and a time-varying least-squares regression (LSR) method were used on patient specific geometric variations of organs of interest manifested on multiple daily volumetric images obtained during the treatment course. The construction of the OSG includes the determination of eigenvectors of the organ variation using PCA, and the determination of the corresponding coefficients using time-varying LSR. The coefficients can be either random variables or random functions of the elapsed treatment days depending on the characteristics of organ variation as a stationary or a nonstationary random process. The LSR method with time-varying weighting parameters was applied to the precollected daily volumetric images to determine the function form of the coefficients. Eleven h and n cancer patients with 30 daily cone beam CT images each were included in the evaluation of the OSG. The evaluation was performed using a total of 18 organs of interest, including 15 organs at risk and 3 targets. Results: Geometric variations of organs of interest during h and n cancer radiotherapy can be represented using the first 3 {approx} 4 eigenvectors. These eigenvectors were variable during treatment, and need to be updated using new daily images obtained during the treatment course. The OSG generates random samples of organs of interest from the estimated organ variation PDF of the individual. The accuracy of the estimated PDF can be improved recursively using extra daily image feedback during the treatment course. The average deviations in the estimation of the mean and standard deviation of the organ variation PDF for h

  13. Nonclinical Evaluations of Small-Molecule Oncology Drugs: Integration into Clinical Dose Optimization and Toxicity Management.

    Science.gov (United States)

    Dambach, Donna M; Simpson, Natalie E; Jones, Thomas W; Brennan, Richard J; Pazdur, Richard; Palmby, Todd R

    2016-06-01

    ARTICLES IN THIS CCR FOCUS SECTION, "NEW APPROACHES FOR OPTIMIZING DOSING OF ANTICANCER AGENTS".

  14. Effect of Intensive Atropine Doses (Rapid Incremental Loading and Titration for Management of Organophosphorus Pesticide Poisoning: a Case Series

    Directory of Open Access Journals (Sweden)

    Abu Saleh Ahmed

    2014-03-01

    Full Text Available Background:Acute poisoning with organophosphorus (OP pesticides is a common method of suicide and entails considerable mortality in Bangladesh. The objective of this study was to evaluate the effects and outcomes of a protocol for treatment of OP poisoning that included titrated incremental atropine as loading dose and slow infusion for maintenance.  Methods:In this prospective descriptive case series, definitive OP poisoned patients were enrolled in an adult medicine unit of Dhaka Medical College Hospital from April 2006 to April 2007. Clinical examinations were done as soon as the patient entered the ward. Patient’s demographics, comorbid conditions and the occurrence of specific clinical outcomes including death, need for assisted ventilation and clinical complications were recorded. The patients were treated according to the protocol. Results: A total of 56 patients were enrolled over the study period. The median age of the study population was 22.5 years. Most patients were men (67.8%. The most common clinical presentation was miosis (58.9%. In total, 11 patients died (19.6%. Intermediate syndrome developed in 12 patients (21.4% and 6 of them died. Assisted ventilation was required in 16 cases (28.5. Patients with diastolic blood pressure ≤ 70 mmHg and/or GCS ≤ 10 were significantly less likely to survive (P = 0.02, 0.006, respectively. Moreover, early respiratory failure (P < 0.001 and the need for assisted ventilation (P < 0.001 were significantly higher among deceased cases. The mortality rate in this study was similar to previous studies. The frequency of atropine toxicity in the present study (1.8% was considerably lower than conventional regimen used in previous studies. Conclusion:Using the new protocol, lower rate of atropine toxicity developed in victims. Hence, the new protocol appears to be safer and its effectiveness should be further evaluated in case control studies in Bangladesh.    How to cite this article: Ahmed AS

  15. Dose optimization in CT examination of children; Dosisoptimierung bei CT-Untersuchungen von Kindern

    Energy Technology Data Exchange (ETDEWEB)

    Hojreh, A.; Prosch, H. [Medizinische Universitaet Wien, Klinische Abteilung fuer Allgemeine und Kinderradiologie, Universitaetsklinik fuer Radiodiagnostik, Wien (Austria)

    2012-10-15

    Problems arise due to the increased clinical use of computed tomography (CT) and the high radiosensitivity of children. The ALARA concept (as low as reasonably achievable) prevails in pediatric radiology. Justified indications and full utilization of available dose optimization methods. Medical physicists and the manufacturers should support pediatric radiology in the implementation of the ALARA concept. The referring physicians and radiology staff should be integrated into training programs. Sufficient diagnostic image quality is paramount and not the pretty images. (orig.) [German] Probleme bestehen durch den zunehmenden klinischen Einsatz der CT in der Kinderradiologie und wegen der Strahlensensibilitaet der Kinder. Es gilt das ALARA-Prinzip (''as low as reasonably achievable'') in der Kinderradiologie. Rechtfertigende Indikation und das Ausschoepfen der zur Verfuegung stehenden dosisoptimierenden Massnahmen. Die Medizinphysik und die Firmen sollten die Kinderradiologie bei der Durchsetzung des ALARA-Prinzips unterstuetzen. Die Zuweiser sollten ebenso wie ihre Mitarbeiter in die Fortbildungsprogramme eingebunden werden. Die ausreichende diagnostische Bildqualitaet steht im Vordergrund und nicht die schoenen Bilder. (orig.)

  16. Optimal dose of zinc supplementation for preventing aluminum-induced neurotoxicity in rats****

    Institute of Scientific and Technical Information of China (English)

    Hao Lu; Yugang Jiang; Jianyang Hu; Jing Li; Wei Pang; Yandan Hu; Hongpeng Yang; Wenjie Li; Chengyu Huang; Mingman Zhang

    2013-01-01

    Zinc supplementation can help maintain learning and memory function in rodents. In this study, we hypothesized that zinc supplementation could antagonize the neurotoxicity induced by aluminum in rats. Animals were fed a diet containing different doses of zinc (50, 100, 200 mg/kg) for 9 weeks, and oral y administered aluminum chloride (300 mg/kg daily) from the third week for 7 consecutive weeks. Open-field behavioral test results showed that the number of rearings in the group given the 100 mg/kg zinc supplement was significantly increased compared with the group given the 50 mg/kg zinc supplement. Malondialdehyde content in the cerebrum was significantly decreased, while dopamine and 5-hydroxytryptamine levels were increased in the groups given the diet plemented with 100 and 200 mg/kg zinc, compared with the group given the diet supplemented with 50 mg/kg zinc. The acetylcholinesterase activity in the cerebrum was significantly decreased in the group given the 100 mg/kg zinc supplement. Hematoxylin-eosin staining revealed evident patho-logical damage in the hippocampus of rats in the group given the diet supplemented with 50 mg/kg zinc, but the damage was attenuated in the groups given the diet supplemented with 100 and 200 mg/kg zinc. Our findings suggest that zinc is a potential neuroprotective agent against alumi-num-induced neurotoxicity in rats, and the optimal dosages are 100 and 200 mg/kg.

  17. Use of tailored loading-dose clopidogrel in patients undergoing selected percutaneous coronary intervention based on adenosine diphosphate-mediated platelet aggregation

    Institute of Scientific and Technical Information of China (English)

    MENG Kang; L(U) Shu-zheng; ZHU Hua-gang; CHEN Xin; GE Chang-jiang; SONG Xian-tao

    2010-01-01

    Background Adenosine phosphate-mediated platelet aggregation is a prognostic factor for major adverse cardiac events in patients who have undergone selective percutaneous coronary interventions. This study aimed to assess whether an adjusted loading dose of clopidogrel could more effectively inhibit platelet aggregation in patients undergoing selected percutaneous coronary intervention.Methods A total of 205 patients undergoing selected percutaneous coronary intervention were enrolled in this multicenter, prospective, randomized study. Patients receiving domestic clopidogrel (n=104) served as the Talcom (Taijia)group; others (n=101) received Plavix, the Plavix group, Patients received up to 3 additional 300-mg loading doses of clopidogrel to decrease the adenosine phosphate-mediated platelet aggregation index by more than 50% (the primary endpoint) compared with the baseline. The secondary endpoint was major adverse cardiovascular events at 12 months.Results Compared with the rational loading dosage, the tailored loading dosage better inhibited platelet aggregation based on a >50% decrease in adenosine phosphate-mediated platelet aggregation (rational loading dosage vs. tailored loading dosage, 48% vs. 73%, P=0.028). There was no significant difference in the eligible index between the Talcom and Plavix groups (47% vs. 49% at 300 mg; 62% vs. 59% at 600 mg; 74% vs. 72% at 900 mg; P >0.05) based on a standard adenosine diphosphate-mediated platelet aggregation decrease of >50%. After 12 months of follow-up, there were no significant differences in major adverse cardiac events (2.5% vs. 2.9%, P=5.43). No acute or subacute stent thrombosis events occurred.Conclusion An adjusted loading dose of clopidogrel could have significant effects on antiplatelet aggregation compared with a rational dose, decreasing 1-year major adverse cardiac events in patients undergoing percutaneous coronary interventions based on adenosine phosphate-mediated platelet aggregation with no

  18. Optimal load for the peak power and maximal strength of the upper body in Brazilian Jiu-Jitsu athletes.

    Science.gov (United States)

    da Silva, Bruno Victor C; Simim, Mário A de Moura; Marocolo, Moacir; Franchini, Emerson; da Mota, Gustavo R

    2015-06-01

    We determined the optimal load for the peak power output (PPO) during the bench press throw (BPT) in Brazilian Jiu-Jitsu (BJJ) athletes and compared the PPO and maximal strength between advanced (AD) and nonadvanced (NA) athletes. Twenty-eight BJJ athletes (24.8 ± 5.7 years) performed the BPT at loads of 30, 40, 50, and 60% of their 1 repetition maximum (RM) in a randomized order (5-minute rest between BPTs). The PPO was determined by measuring the barbell displacement by an accelerometer (Myotest). The absolute (F = 7.25; p 0.05) in the PPO (30-60% 1RM). A polynomial adjustment indicated that the optimal load was ∼42% of 1RM for all groups and subgroups (R from 0.82 to 0.99). Our results suggest that there can be (1RM) differences between AD and NA BJJ athletes; however, there is no difference in the muscle power between the AD and NA groups. Additionally, ∼42% of 1RM seems to be the optimal load for developing maximal power using the BPT for the BJJ athletes.

  19. The optimal parameter for radiation dose in pediatric low dose abdominal CT: cross-sectional dimensions versus body weight

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Yoon Young; Goo, Hyun Woo [Asan Medical Center, University of Ulsan, College of Medicine, Seoul (Korea, Republic of)

    2008-02-15

    To investigate the best parameter between cross-sectional dimensions and body weight in pediatric low dose abdominal CT. One hundred and thirty six children consecutively underwent weight-based abdominal CT. The subjects consisted of group 1 (79 children, weight range 10.0-19.9 kg) and group 2 (57 children, weight range 20.0-39.9 kg). Abdominal cross-sectional dimensions including circumference, area, anteroposterior diameters and transverse diameters were calculated. Image noise (standard deviation of CT density) was measured by placing a region of interest in the posterior segment of the right hepatic lobe on a CT image at the celiac axis. The measured image noise was correlated with the cross-sectional abdominal dimensions and body weight for subjects in each group. In group 1 subjects,area, circumference, transverse diameter, anteroposterior diameter, and body weight showed a significant positive correlation with image noise in descending order({gamma} = 0.63, 0.62, 0.61, 0.51, and 0.49; {rho} < 0.0001). In group 2 subjects, transverse diameter, circumference, area, anteroposterior diameter, and body weight showed a significant positive correlation with image noise in descending order ({gamma} = 0.83, 0.82, 0.78, 0.71, and 0.71; {rho} < 0.0001). Cross-sectional dimensions such as area, circumference, and transverse diameter showed a higher positive correlation with image noise than body weight for pediatric low dose abdominal CT.

  20. Optimizing Collimator Margins for Isotoxically Dose-Escalated Conformal Radiation Therapy of Non-Small Cell Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Warren, Samantha, E-mail: Samantha.warren@oncology.ox.ac.uk [Department of Oncology, Gray Institute of Radiation Oncology and Biology, University of Oxford, Oxford (United Kingdom); Oxford Cancer Centre, Oxford University Hospitals, Oxford (United Kingdom); Panettieri, Vanessa [William Buckland Radiotherapy Centre, Alfred Hospital, Commercial Road, Melbourne (Australia); Panakis, Niki; Bates, Nicholas [Oxford Cancer Centre, Oxford University Hospitals, Oxford (United Kingdom); Lester, Jason F. [Velindre Cancer Centre, Velindre Road, Whitchurch, Cardiff (United Kingdom); Jain, Pooja [Clatterbridge Cancer Centre, Clatterbridge Road, Wirral (United Kingdom); Landau, David B. [Department of Radiotherapy, Guy' s and St. Thomas' NHS Foundation Trust, London (United Kingdom); Nahum, Alan E.; Mayles, W. Philip M. [Clatterbridge Cancer Centre, Clatterbridge Road, Wirral (United Kingdom); Fenwick, John D. [Department of Oncology, Gray Institute of Radiation Oncology and Biology, University of Oxford, Oxford (United Kingdom); Oxford Cancer Centre, Oxford University Hospitals, Oxford (United Kingdom)

    2014-04-01

    Purpose: Isotoxic dose escalation schedules such as IDEAL-CRT [isotoxic dose escalation and acceleration in lung cancer chemoradiation therapy] (ISRCTN12155469) individualize doses prescribed to lung tumors, generating a fixed modeled risk of radiation pneumonitis. Because the beam penumbra is broadened in lung, the choice of collimator margin is an important element of the optimization of isotoxic conformal radiation therapy for lung cancer. Methods and Materials: Twelve patients with stage I-III non-small cell lung cancer (NSCLC) were replanned retrospectively using a range of collimator margins. For each plan, the prescribed dose was calculated according to the IDEAL-CRT isotoxic prescription method, and the absolute dose (D{sub 99}) delivered to 99% of the planning target volume (PTV) was determined. Results: Reducing the multileaf collimator margin from the widely used 7 mm to a value of 2 mm produced gains of 2.1 to 15.6 Gy in absolute PTV D{sub 99}, with a mean gain ± 1 standard error of the mean of 6.2 ± 1.1 Gy (2-sided P<.001). Conclusions: For NSCLC patients treated with conformal radiation therapy and an isotoxic dose prescription, absolute doses in the PTV may be increased by using smaller collimator margins, reductions in relative coverage being offset by increases in prescribed dose.

  1. Dose optimization in gynecological 3D image based interstitial brachytherapy using martinez universal perineal interstitial template (MUPIT -an institutional experience

    Directory of Open Access Journals (Sweden)

    Pramod Kumar Sharma

    2014-01-01

    Full Text Available The aim of this study was to evaluate the dose optimization in 3D image based gynecological interstitial brachytherapy using Martinez Universal Perineal Interstitial Template (MUPIT. Axial CT image data set of 20 patients of gynecological cancer who underwent external radiotherapy and high dose rate (HDR interstitial brachytherapy using MUPIT was employed to delineate clinical target volume (CTV and organs at risk (OARs. Geometrical and graphical optimization were done for optimum CTV coverage and sparing of OARs. Coverage Index (CI, dose homogeneity index (DHI, overdose index (OI, dose non-uniformity ratio (DNR, external volume index (EI, conformity index (COIN and dose volume parameters recommended by GEC-ESTRO were evaluated. The mean CTV, bladder and rectum volume were 137 ± 47cc, 106 ± 41cc and 50 ± 25cc, respectively. Mean CI, DHI and DNR were 0.86 ± 0.03, 0.69 ± 0.11 and 0.31 ± 0.09, while the mean OI, EI, and COIN were 0.08 ± 0.03, 0.07 ± 0.05 and 0.79 ± 0.05, respectively. The estimated mean CTV D90 was 76 ± 11Gy and D100 was 63 ± 9Gy. The different dosimetric parameters of bladder D2cc, D1cc and D0.1cc were 76 ± 11Gy, 81 ± 14Gy, and 98 ± 21Gy and of rectum/recto-sigmoid were 80 ± 17Gy, 85 ± 13Gy, and 124 ± 37Gy, respectively. Dose optimization yields superior coverage with optimal values of indices. Emerging data on 3D image based brachytherapy with reporting and clinical correlation of DVH parameters outcome is enterprizing and provides definite assistance in improving the quality of brachytherapy implants. DVH parameter for urethra in gynecological implants needs to be defined further.

  2. Topical ketoprofen nanogel: artificial neural network optimization, clustered bootstrap validation, and in vivo activity evaluation based on longitudinal dose response modeling.

    Science.gov (United States)

    Elkomy, Mohammed H; Elmenshawe, Shahira F; Eid, Hussein M; Ali, Ahmed M A

    2016-11-01

    This work aimed at investigating the potential of solid lipid nanoparticles (SLN) as carriers for topical delivery of Ketoprofen (KP); evaluating a novel technique incorporating Artificial Neural Network (ANN) and clustered bootstrap for optimization of KP-loaded SLN (KP-SLN); and demonstrating a longitudinal dose response (LDR) modeling-based approach to compare the activity of topical non-steroidal anti-inflammatory drug formulations. KP-SLN was fabricated by a modified emulsion/solvent evaporation method. Box-Behnken design was implemented to study the influence of glycerylpalmitostearate-to-KP ratio, Tween 80, and lecithin concentrations on particle size, entrapment efficiency, and amount of drug permeated through rat skin in 24 hours. Following clustered bootstrap ANN optimization, the optimized KP-SLN was incorporated into an aqueous gel and evaluated for rheology, in vitro release, permeability, skin irritation and in vivo activity using carrageenan-induced rat paw edema model and LDR mathematical model to analyze the time course of anti-inflammatory effect at various application durations. Lipid-to-drug ratio of 7.85 [bootstrap 95%CI: 7.63-8.51], Tween 80 of 1.27% [bootstrap 95%CI: 0.601-2.40%], and Lecithin of 0.263% [bootstrap 95%CI: 0.263-0.328%] were predicted to produce optimal characteristics. Compared with profenid® gel, the optimized KP-SLN gel exhibited slower release, faster permeability, better texture properties, greater efficacy, and similar potency. SLNs are safe and effective permeation enhancers. ANN coupled with clustered bootstrap is a useful method for finding optimal solutions and estimating uncertainty associated with them. LDR models allow mechanistic understanding of comparative in vivo performances of different topical formulations, and help design efficient dermatological bioequivalence assessment methods.

  3. Statistical optimization of dithranol-loaded solid lipid nanoparticles using factorial design

    Directory of Open Access Journals (Sweden)

    Makarand Suresh Gambhire

    2011-09-01

    Full Text Available This study describes a 3² full factorial experimental design to optimize the formulation of dithranol (DTH loaded solid lipid nanoparticles (SLN by the pre-emulsion ultrasonication method. The variables drug: lipid ratio and sonication time were studied at three levels and arranged in a 3² factorial design to study the influence on the response variables particle size and % entrapment efficiency (%EE. From the statistical analysis of data polynomial equations were generated. The particle size and %EE for the 9 batches (R1 to R9 showed a wide variation of 219-348 nm and 51.33- 71.80 %, respectively. The physical characteristics of DTH-loaded SLN were evaluated using a particle size analyzer, differential scanning calorimetry and X-ray diffraction. The results of the optimized formulation showed an average particle size of 219 nm and entrapment efficiency of 69.88 %. Ex-vivo drug penetration using rat skin showed about a 2-fold increase in localization of DTH in skin as compared to the marketed preparation of DTH.Este estudo descreve o planejamento factorial 3² para otimizar a formulação de nanopartículas lipídicas sólidas (SLN carregadas com ditranol (DTH pelo método da ultrassonificação pré-emulsão. As variáveis como proporção de fármaco:lipídio e o tempo de sonicação foram estudados em três níveis e arranjados em planejamento fatorial 3² para estudar a influência nas variáveis de resposta tamanho de partícula e eficiência percentual de retenção do fármaco (%EE. Pela análise estatística, geraram-se equações polinomiais. O tamanho da partícula e a %EE para os 9 lotes (R1 a R9 mostraram ampla variação, respectivamente, 219-348 nm e 51,33-71,80%. As características físicas das SLN carregadas com DTN foram avaliadas utilizando-se analisador de tamanho de partícula, calorimetria de varredura diferencial e difração de raios X. Os resultados da formulação otimizada mostraram tamanho médio de partícula de

  4. Short-Term Load Forecasting Based on Wavelet Transform and Least Squares Support Vector Machine Optimized by Fruit Fly Optimization Algorithm

    Directory of Open Access Journals (Sweden)

    Wei Sun

    2015-01-01

    Full Text Available Electric power is a kind of unstorable energy concerning the national welfare and the people’s livelihood, the stability of which is attracting more and more attention. Because the short-term power load is always interfered by various external factors with the characteristics like high volatility and instability, a single model is not suitable for short-term load forecasting due to low accuracy. In order to solve this problem, this paper proposes a new model based on wavelet transform and the least squares support vector machine (LSSVM which is optimized by fruit fly algorithm (FOA for short-term load forecasting. Wavelet transform is used to remove error points and enhance the stability of the data. Fruit fly algorithm is applied to optimize the parameters of LSSVM, avoiding the randomness and inaccuracy to parameters setting. The result of implementation of short-term load forecasting demonstrates that the hybrid model can be used in the short-term forecasting of the power system.

  5. The Erlangen Dose Optimization trial for low-dose radiotherapy of benign painful elbow syndrome. Long-term results

    Energy Technology Data Exchange (ETDEWEB)

    Ott, O.J.; Hertel, S.; Gaipl, U.S.; Frey, B.; Schmidt, M.; Fietkau, R. [University Hospital Erlangen, Department of Radiation Oncology, Erlangen (Germany)

    2014-03-15

    To evaluate the long-term efficacy of pain reduction by two dose fractionation schedules used for low-dose radiotherapy of painful elbow syndrome. Between February 2006 and February 2010, 199 evaluable patients were recruited for this prospective trial. All patients received low-dose orthovoltage radiotherapy. One course consisted of 6 fractions in 3 weeks. In the case of insufficient pain remission after 6 weeks, a second course was administered. Patients were randomly assigned to one of two groups to receive single doses of either 0.5 or 1.0 Gy. Endpoint was pain reduction. Pain was measured before radiotherapy, as well as immediately after (early response), 6 weeks after (delayed response) and approximately 3 years after (long-term response) completion of radiotherapy using a questionnaire-based visual analogue scale (VAS) and a comprehensive pain score (CPS). Median follow-up was 35 months (range 9-57 months). The overall early, delayed and long-term response rates for all patients were 80, 90 and 94 %, respectively. The mean VAS scores before treatment and those for early, delayed and long-term response in the 0.5- and 1.0-Gy groups were 59.6 ± 20.2 and 55.7 ± 18.0 (p = 0.46); 32.1 ± 24.5 and 34.4 ± 22.5 (p = 0.26); 27.0 ± 27.7 and 23.5 ± 21.6 (p = 0.82) and 10.7 ± 15.0 and 21.5 ± 26.9 (p = 0.12), respectively. The mean CPS values before treatment and those for early, delayed and long-term response were 8.7 ± 2.9 and 8.1 ± 3.1 (p = 0.21); 4.5 ± 3.2 and 5.0 ± 3.4 (p = 0.51); 3.9 ± 3.6 and 2.8 ± 2.8 (p = 0.19) and 1.5 ± 2.3 and 2.4 ± 3.5 (p = 0.27), respectively. No significant differences in the quality of the long-term response were found between the 0.5- and 1.0-Gy arms (p = 0.28). Low-dose radiotherapy is an effective treatment for the management of benign painful elbow syndrome. For radiation protection reasons, the dose for a radiotherapy series should not exceed 3.0 Gy. (orig.) [German] Untersuchung der

  6. Time/motion observations and dose analysis of reactor loading, transportation, and dry unloading of an overweight truck spent fuel shipment

    Energy Technology Data Exchange (ETDEWEB)

    Hostick, C.J. (Pacific Northwest Lab., Richland, WA (United States)); Lavender, J.C. (Westinghouse Hanford Co., Richland, WA (United States)); Wakeman, B.H. (Virginia Electric and Power Co., Richmond, VA (United States))

    1992-04-01

    This document presents observed activity durations and radiation dose analyses for an overweight truck shipment of pressurized water reactor (PWR) spent fuel from the Surry Power Station in Virginia to the Idaho National Engineering Laboratory. The shipment consisted of a TN-8L shipping cask carrying three 9-year-old PWR spent fuel assemblies. Handling times and dose analyses for at-reactor activities were completed by Virginia Electric and Power Company (Virginia Power) personnel. Observations of in-transit and unloading activities were made by Pacific Northwest Laboratory (PNL) personnel, who followed the shipment for approximately 2800 miles and observed cask unloading activities. In-transit dose estimates were calculated using dose rate maps provided by Virginia Power for a fully loaded TN-8L shipping cask. The dose analysis for the cask unloading operations is based on the observations of PNL personnel.

  7. Time/motion observations and dose analysis of reactor loading, transportation, and dry unloading of an overweight truck spent fuel shipment

    Energy Technology Data Exchange (ETDEWEB)

    Hostick, C.J. [Pacific Northwest Lab., Richland, WA (United States); Lavender, J.C. [Westinghouse Hanford Co., Richland, WA (United States); Wakeman, B.H. [Virginia Electric and Power Co., Richmond, VA (United States)

    1992-04-01

    This document presents observed activity durations and radiation dose analyses for an overweight truck shipment of pressurized water reactor (PWR) spent fuel from the Surry Power Station in Virginia to the Idaho National Engineering Laboratory. The shipment consisted of a TN-8L shipping cask carrying three 9-year-old PWR spent fuel assemblies. Handling times and dose analyses for at-reactor activities were completed by Virginia Electric and Power Company (Virginia Power) personnel. Observations of in-transit and unloading activities were made by Pacific Northwest Laboratory (PNL) personnel, who followed the shipment for approximately 2800 miles and observed cask unloading activities. In-transit dose estimates were calculated using dose rate maps provided by Virginia Power for a fully loaded TN-8L shipping cask. The dose analysis for the cask unloading operations is based on the observations of PNL personnel.

  8. On expedient properties of common biological score functions for multi-modality, adaptive and 4D dose optimization

    Energy Technology Data Exchange (ETDEWEB)

    Sobotta, B; Alber, M [Section for Biomedical Physics, Radioonkologische Uniklinik, Universitaet Tuebingen, 72076 Tuebingen (Germany); Soehn, M [Department of Radiation Oncology, University Hospital Grosshadern, LMU Muenchen, 81377 Muenchen (Germany); Shaw, W, E-mail: benjamin.sobotta@med.uni-tuebingen.de [Department of Medical Physics, Faculty of Health Sciences, University of the Free State, PO Box 339, Bloemfontein 9300 (South Africa)

    2011-05-21

    Frequently, radiotherapy treatments are comprised of several dose distributions computed or optimized in different patient geometries. Therefore, the need arises to compute the comprehensive biological effect or physical figure of merit of the combined dose of a number of distinct geometry instances. For that purpose the dose is typically accumulated in a reference geometry through deformation fields obtained from deformable image registration. However, it is difficult to establish precise voxel-by-voxel relationships between different anatomical images in many cases. In this work, the mathematical properties of commonly used score functions are exploited to derive an upper boundary for the maximum effect for normal tissue and a lower boundary for the minimum effect for the target of accumulated doses on multiple geometry instances. (note)

  9. On expedient properties of common biological score functions for multi-modality, adaptive and 4D dose optimization.

    Science.gov (United States)

    Sobotta, B; Söhn, M; Shaw, W; Alber, M

    2011-05-21

    Frequently, radiotherapy treatments are comprised of several dose distributions computed or optimized in different patient geometries. Therefore, the need arises to compute the comprehensive biological effect or physical figure of merit of the combined dose of a number of distinct geometry instances. For that purpose the dose is typically accumulated in a reference geometry through deformation fields obtained from deformable image registration. However, it is difficult to establish precise voxel-by-voxel relationships between different anatomical images in many cases. In this work, the mathematical properties of commonly used score functions are exploited to derive an upper boundary for the maximum effect for normal tissue and a lower boundary for the minimum effect for the target of accumulated doses on multiple geometry instances.

  10. Population pharmacokinetics of intravenous busulfan in children: revised body weight-dependent NONMEM® model to optimize dosing.

    Science.gov (United States)

    Diestelhorst, Christian; Boos, Joachim; McCune, Jeannine S; Hempel, Georg

    2014-07-01

    We developed a new population pharmacokinetic (PopPK) model for intravenous (i.v.) busulfan in children to evaluate the optimal method to personalize its dosing without concentration-time data. PopPK analyses were done with NONMEM® 7.2. First, a model from Trame et al. was evaluated using an external dataset consisting of 24 children. Second, a revised model was built in a separate dataset of 82 children. Model evaluation was performed by using a standardized visual predictive check (SVPC) procedure and a bootstrap analysis (internal evaluation) and by comparison to an external dataset (external validation). The final model included body surface area (BSA) as an exponential function on volume of distribution (V) and actual body weight (ABW) as an allometric function on clearance (CL). The dosing nomogram for every 6 h administration derived from the final model is: dose[mg]=target AUC[mg×h/L]×3.04L/h×(ABW/16.1)0.797. Compared to other dosing strategies, differences were observed for the very small and obese patients. We revised our prior dosing nomogram after validation in a separate cohort of children. This dosing nomogram can be used to personalize i.v. busulfan doses without concentration-time data, but an additional prospective evaluation in the very small and obese children is needed.

  11. Reduction of fatigue loads on jacket substructure through blade design optimization for multimegawatt wind turbines at 50 m water depths

    DEFF Research Database (Denmark)

    NJOMO WANDJI, Wilfried; Pavese, Christian; Natarajan, Anand;

    2016-01-01

    This paper addresses the reduction of the fore-aft damage equivalent moment at the tower base for multi-megawatt offshore wind turbines mounted on jacket type substructures at 50 m water depths. The study investigates blade design optimization of a reference 10 MW wind turbine under standard wind...... conditions of onshore sites. The blade geometry and structure is optimized to yield a design that minimizes tower base fatigue loads without significant loss of power production compared to that of the reference setup. The resulting blade design is then mounted on a turbine supported by a jacket and placed...

  12. Comparative evaluation of two different loading doses of dexmedetomidine with midazolam-fentanyl for sedation in vitreoretinal surgery under peribulbar anaesthesia

    Directory of Open Access Journals (Sweden)

    Suman Shree Ramaswamy

    2016-01-01

    Full Text Available Background and Aims: Midazolam-fentanyl (MDZ:FEN combination has been routinely used for intravenous sedation in ophthalmic surgeries. Dexmedetomidine (DEX, a recent α2 adrenoreceptor agonist indicated for sedation for ophthalmic use at a loading dose of 0.5 μg/kg over 10 min, can cause deeper plane of sedation and surgeon dissatisfaction. Therefore, we proposed to evaluate the efficacy and safety of two different loading doses of DEX. Methods: In a prospective study, 60 patients aged 50-70 years, scheduled for retinal surgery under peribulbar block were divided equally to receive either MDZ:FEN or DEX 0.5 μg/kg (DEX full or DEX 0.25 μg/kg (DEX half loading dose over 10 min followed by titrated maintenance dose of DEX 0.25-0.4 μg/kg/h. Vital parameters, level of sedation (Ramsay Sedation Scale 1–6, effect on respiration and surgeon satisfaction were assessed at regular intervals. Surgeon satisfaction score (0–3 was noted. Results: 'DEX half' group patients had predominantly stable haemodynamics, level 3 sedation and surgeon satisfaction score of 2–3 (good to excellent operating conditions. This group had no vomiting and no respiratory depression. 'DEX full' group had a higher incidence of bradycardia, hypotension, level 4 sedation (Ramsay Sedation Scale and lower surgeon satisfaction. Incidence of nausea and vomiting was higher in MDZ:FEN group compared to other two groups. Conclusion: DEX 0.25 μg/kg loading dose over 10 min followed by titrated maintenance dose is an effective alternative to MDZ:FEN and provides controlled (level 3 sedation and stable haemodynamics maximising surgeon satisfaction. Avoiding narcotic analgesics with its associated post-operative nausea and vomiting is an additional benefit.

  13. (90) Y/(177) Lu-labelled Cetuximab immunoconjugates: radiochemistry optimization to clinical dose formulation.

    Science.gov (United States)

    Chakravarty, Rubel; Chakraborty, Sudipta; Sarma, Haladhar Dev; Nair, K V Vimalnath; Rajeswari, Ardhi; Dash, Ashutosh

    2016-07-01

    Radiolabelled monoclonal antibodies (mAbs) are increasingly being utilized in cancer theranostics, which is a significant move toward tailored treatment for individual patients. Cetuximab is a recombinant, human-mouse chimeric IgG1 mAb that binds to the epidermal growth factor receptor with high affinity. We have optimized a protocol for formulation of clinically relevant doses (~2.22 GBq) of (90) Y-labelled Cetuximab and (177) Lu-labelled Cetuximab by conjugation of the mAb with a suitable bifunctional chelator, N-[(R)-2-amino-3-(paraisothiocyanato-phenyl)propyl]-trans-(S,S)-cyclohexane-1,2-diamine-N,N,N',N″,N″-pentaacetic acid (CHX-A″-DTPA). The radioimmunoconjugates demonstrated reasonably high specific activity (1.26 ± 0.27 GBq/mg for (90) Y-CHX-A″-DTPA-Cetuximab and 1.14 ± 0.15 GBq/mg for (177) Lu-CHX-A″-DTPA-Cetuximab), high radiochemical purity (>95%) and appreciable in vitro stability under physiological conditions. Preliminary biodistribution studies with both (90) Y-CHX-A″-DTPA-Cetuximab and (177) Lu-CHX-A″-DTPA-Cetuximab in Swiss mice bearing fibrosarcoma tumours demonstrated significant tumour uptake at 24-h post-injection (p.i.) (~16%ID/g) with good tumour-to-background contrast. The results of the biodistribution studies were further corroborated by ex vivo Cerenkov luminescence imaging after administration of (90) Y-CHX-A″-DTPA-Cetuximab in tumour-bearing mice. The tumour uptake at 24 h p.i. was significantly reduced with excess unlabelled Cetuximab, suggesting that the uptake was receptor mediated. The results of this study hold promise, and this strategy should be further explored for clinical translation.

  14. CANopen协议总线负载优化的研究%Research on Bus Load Optimization of CANopen protocol

    Institute of Scientific and Technical Information of China (English)

    冯化

    2016-01-01

    The paper introduces CAN and CANopen protocol, and describes the bus load of CANopen protocol in detail. A method is pro-posed to optimize the bus load through the setting of bus communication rate and PDO communication type. The actual results prove that this method can effectively control the bus load.%介绍了CAN和CANopen协议,并对CANopen协议的总线负载进行了详细的描述,提出了通过总线通信速率和PDO通信类型的设置对总线负载进行优化的方法,实际证明该方法可以有效的控制总线负载。

  15. Optimizing the structure of metal load in order to reduce electricity consumption in the production of steel

    Science.gov (United States)

    Pǎcurar, Cristina; Hepuť, Teodor; Ardelean, Marius

    2016-06-01

    As the basic units in the preparation of steel, in industrial practice is used oxygen converters and electric arc furnaces. In research carried out has been taken into account structure analysis load electric arc furnaces of the specific consumption of electricity (kWh/t). Data to be achieved for a number of 96 batches, have been taken into account load holding metal of each assortment of scrap metal, these varieties being considered as independent parameters, and electricity consumption is considered dependent parameter. By processing the data in the EXCEL spreadsheet programs and MATLAB have been obtained correlations between parameters analyze, analytical results being presented and the graph. On the basis of an analysis of these correlations to choose optimal structure of the load in order to obtain an acceptable energy consumption from technical and economic point of view.

  16. Short-Term Load Forecasting Based on Wavelet Transform and Least Squares Support Vector Machine Optimized by Improved Cuckoo Search

    Directory of Open Access Journals (Sweden)

    Yi Liang

    2016-10-01

    Full Text Available Due to the electricity market deregulation and integration of renewable resources, electrical load forecasting is becoming increasingly important for the Chinese government in recent years. The electric load cannot be exactly predicted only by a single model, because the short-term electric load is disturbed by several external factors, leading to the characteristics of volatility and instability. To end this, this paper proposes a hybrid model based on wavelet transform (WT and least squares support vector machine (LSSVM, which is optimized by an improved cuckoo search (CS. To improve the accuracy of prediction, the WT is used to eliminate the high frequency components of the previous day’s load data. Additional, the Gauss disturbance is applied to the process of establishing new solutions based on CS to improve the convergence speed and search ability. Finally, the parameters of the LSSVM model are optimized by using the improved cuckoo search. According to the research outcome, the result of the implementation demonstrates that the hybrid model can be used in the short-term forecasting of the power system.

  17. DESIGN OPTIMIZATION FOR TRUSS STRUCTURES UNDER ELASTO-PLASTIC LOADING CONDITION

    Institute of Scientific and Technical Information of China (English)

    Liu Tao; Deng Zichen

    2006-01-01

    In this paper, a method for the design optimization of elasto-plastic truss structures is proposed based on parametric variational principles (PVPs). The optimization aims to find the minimum weight/volume solution under the constraints of allowable node displacements. The design optimization is a formulation of mathematical programming with equilibrium constraints (MPECs). To overcome the numerical difficulties of the complementary constraints in optimization, an iteration process, comprising a quadratic programming (QP) and an updating process,is employed as the optimization method. Furthermore, the elasto-plastic buckling of truss members is considered as a constraint in design optimization. A combinational optimization strategy is proposed for the displacement constraints and the buckling constraint, which comprises the method mentioned above and an optimal criterion. Three numerical examples are presented to show the validity of the methods proposed.

  18. Optimizing the current therapy for chronic hepatitis C virus: peginterferon and ribavirin dosing and the utility of growth factors.

    Science.gov (United States)

    Shiffman, Mitchell L

    2008-08-01

    Achieving a sustained virologic response depends on the patient achieving three sequential independent milestones: virologic response, maintaining this response throughout treatment, and not relapsing after treatment has been completed. The ability to achieve these milestones depends on the doses of interferon/peginterferon and ribavirin used and on whether treatment with these medications is adjusted, interrupted, or prematurely discontinued in response to adverse events. This review discusses strategies to optimize peginterferon and ribavirin dosing and the impact that growth factors may have on the ability to achieve a sustained virologic response.

  19. Simultaneous optimization of dose distributions and fractionation schemes in particle radiotherapy

    NARCIS (Netherlands)

    Unkelbach, J.; Zeng, C.; Engelsman, M.

    2013-01-01

    Purpose: The paper considers the fractionation problem in intensity modulated proton therapy (IMPT). Conventionally, IMPT fields are optimized independently of the fractionation scheme. In this work, we discuss the simultaneous optimization of fractionation scheme and pencil beam intensities. Meth

  20. Determination of the optimal minimum radioiodine dose in patients with Graves' disease: a clinical outcome study

    Energy Technology Data Exchange (ETDEWEB)

    Howarth, D.; Tan, P.; Booker, J. [Pacific Medical Imaging, Newcastle, NSW (Australia); Epstein, M. [Dept. of Endocrinology, John Hunter Hospital, Newcastle, NSW (Australia); Lan, L. [High-Dependency Unit, St. George Hospital, Sydney, NSW (Australia)

    2001-10-01

    The study was performed under the auspices of the International Atomic Energy Commission, Vienna, Austria, with the aim of determining the optimal minimum therapeutic dose of iodine-131 for Graves' disease. The study was designed as a single-blinded randomised prospective outcome trial. Fifty-eight patients were enrolled, consisting of 50 females and 8 males aged from 17 to 75 years. Each patient was investigated by clinical assessment, biochemical and immunological assessment, thyroid ultrasound, technetium-99m thyroid scintigraphy and 24-h thyroid {sup 131}I uptake. Patients were then randomised into two treatment groups, one receiving 60 Gy and the other receiving 90 Gy thyroid tissue absorbed dose of radioiodine. The end-point markers were clinical and biochemical response to treatment. The median follow-up period was 37.5 months (range, 24-48 months). Among the 57 patients who completed final follow-up, a euthyroid state was achieved in 26 patients (46%), 27 patients (47%) were rendered hypothyroid and four patients (7%) remained hyperthyroid. Thirty-four patients (60%) remained hyperthyroid at 6 months after the initial radioiodine dose (median dose 126 MBq), and a total of 21 patients required additional radioiodine therapy (median total dose 640 MBq; range 370-1,485 MBq). At 6-month follow-up, of the 29 patients who received a thyroid tissue dose of 90 Gy, 17 (59%) remained hyperthyroid. By comparison, of the 28 patients who received a thyroid tissue dose of 60 Gy, 17 (61%) remained hyperthyroid. No significant difference in treatment response was found (P=0.881). At 6 months, five patients in the 90-Gy group were hypothyroid, compared to two patients in the 60-Gy group (P=0.246). Overall at 6 months, non-responders to low-dose therapy had a significantly larger thyroid gland mass (respective means: 35.9 ml vs 21.9 ml) and significantly higher levels of serum thyroglobulin (respective means: 597.6 {mu}g/l vs 96.9 {mu}g/l). Where low-dose radioiodine

  1. Curcumin-loaded polysaccharide nanoparticles: Optimization and anticariogenic activity against Streptococcus mutans.

    Science.gov (United States)

    Maghsoudi, Amir; Yazdian, Fatemeh; Shahmoradi, Saleheh; Ghaderi, Leila; Hemati, Mehran; Amoabediny, Ghassem

    2017-06-01

    Curcumin was loaded into different polysaccharide nanoparticles chitosan, alginate and starch, using the desolvation method. Curcumin-loaded nanoparticles exhibited enhanced solubility in aqueous solutions comparing with free curcumin. Effects of formulation parameters such as curcumin concentration and different volumes of ethanolic solution were affected the particle size and loading efficiency. Under optimum conditions, curcumin-loaded chitosan, starch and alginate nanoparticles with mean particles sizes of 66.3, 61.1 and 78.8nm, and maximum loading efficiencies of 11.9%, 14.3% and 13.35% were achieved, respectively. Additionally, the minimum inhibitory concentration for chitosan, starch and alginate nanoparticles against the microorganism, Streptococcus mutans, were 0.114, 0.204 and 0.204mg/mL, respectively. Curcumin was observed to release from nanoparticles under physiological pH over a period of 96h. The effect of curcumin-loaded nanoparticles on S. mutans biofilms was assessed on dental models. According to the results, curcumin-loaded chitosan nanoparticles hold promises for being used in dental decay fighting products. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. On the combination of c- and D-optimal designs: General approaches and applications in dose-response studies.

    Science.gov (United States)

    Holland-Letz, Tim

    2017-03-01

    Dose-response modeling in areas such as toxicology is often conducted using a parametric approach. While estimation of parameters is usually one of the goals, often the main aim of the study is the estimation of quantities derived from the parameters, such as the ED50 dose. From the view of statistical optimal design theory such an objective corresponds to a c-optimal design criterion. Unfortunately, c-optimal designs often create practical problems, and furthermore commonly do not allow actual estimation of the parameters. It is therefore useful to consider alternative designs which show good c-performance, while still being applicable in practice and allowing reasonably good general parameter estimation. In effect, using optimal design terminology this means that a reasonable performance regarding the D-criterion is expected as well. In this article, we propose several approaches to the task of combining c- and D-efficient designs, such as using mixed information functions or setting minimum requirements regarding either c- or D-efficiency, and show how to algorithmically determine optimal designs in each case. We apply all approaches to a standard situation from toxicology, and obtain a much better balance between c- and D-performance. Next, we investigate how to adapt the designs to different parameter values. Finally, we show that the methodology used here is not just limited to the combination of c- and D-designs, but can also be used to handle more general constraint situations such as limits on the cost of an experiment.

  3. Effect of high-dose rosuvastatin loading before percutaneous coronary intervention in Chinese patients with acute coronary syndrome: A systematic review and meta-analysis

    Science.gov (United States)

    Su, Qiang; Guo, Wenqin; Dai, Weiran; Li, Hongqing; Yang, Huafeng; Li, Lang

    2017-01-01

    Background Acute coronary syndrome (ACS) is an important disease threatening human life and health. Many studies have shown that the loading dose of atorvastatin can significantly improve the prognosis of patients with ACS, and reduce the mortality. However, this conclusion is not consistent. Thus, we aimed to evaluate the effect of high-dose rosuvastatin loading before percutaneous coronary intervention (PCI) in Chinese patients with ACS using a meta-analysis based on a systematic review of published articles. Methods We systematically reviewed published studies, evaluating the effect of high-dose rosuvastatin loading before percutaneous coronary intervention in Chinese patients with ACS. The retrieval time is limited from inception to 2 November 2016, and the retrieved databases included PubMed, Embase, the Cochrane Library, Web of Science, CBM, CNKI, the VIP database and the Wang Fang database. Two researchers independently assessed the quality of the included studies and then extracted the data. Stata 11.0 was used for data analysis. Results In total, 11 articles, which included 802 patients, were included in our meta-analysis. Among these patients, 398 patients were in the high-dose group (20 mg/day) and 404 patients were in the conventional dose group (10 mg/day). Meta-analysis results showed that compared with the conventional dose group: 1) The loading dose of rosuvastatin can significantly reduce the hs-CRP level after PCI, including at 24 hours (SMD = -0.65, 95%CI -0.84 ~ -0.47, P = 0.000), 48 hours (SMD = -0.40, 95%CI -0.68 ~ -0.11, P = 0.006), and four weeks (SMD = -1.64, 95%CI -2.01 ~ -1.26, P = 0.000). 2) The loading dose of rosuvastatin can significantly reduce the levels of LDL-C and cTnT, including the level of LDL-C at 30 d after PCI (SMD = -0.89, 95%CI -1.10 ~ -0.69, P = 0.000), and the level of cTnT at 24 h after PCI (SMD = -1.93, 95%CI -2.28 ~ -1.59, P = 0.000), and increase the level of HDL-C at 48 h after PCI (SMD = 0.61, 95%CI 0.34 ~ 0.88, P

  4. Calculating Ivalent Dose Rate Field Structure Applying the Method of Optimal Interpollation in the Baltic Sea Coast

    Directory of Open Access Journals (Sweden)

    Dmitrijus Styra

    2011-04-01

    Full Text Available Equivalent dose rate measurements were carried out in the Baltic Sea coast near Juodkrantė. The measurements were performed at the ground level and 1 meter above it at 63 points within the territory of 2,0´0,2 km on 2 July 2008 and 10 July 2008 under conditions of northern and southern wind directions respectively. The extreme rates of the equivalent dose rate were 51 and 90 nSv/h respectively which means that the structure of the equivalent dose field was unhomogeneous. The method of optimal interpollation was used to calculate and evaluate the structure of the equivalent dose rate field. This method was used in 3 cases when 63, 33 and 18 numbers of measurement were carried out. The identical structures of the equivalent dose field were accepted. Using 18 measurement points, coincidence between the measured and calculated values of the equivalent dose rate was satisfactory. Difference between the measured and calculated values does not exceed 15% in 80% of the measurement points.Article in Lithuanian

  5. Cooling load optimization of an irreversible refrigerator with combined heat transfer

    Directory of Open Access Journals (Sweden)

    M. El Haj Assad

    2013-01-01

    Full Text Available In this work a mathematical model to study the performance of an irreversible refrigerator has been presented with the consideration of heat exchange by combined convection and radiation. The external irreversibility effects due to finite rate heat transfer as well as the effects of internal dissipations have been considered in the analysis. The relation between the cooling load and the coefficient of performance of the refrigerator has been derived. Furthermore an expression for the maximum cooling rate has been derived. The parameters that affect the cooling load have been investigated. The cooling load has been discussed and the effect of internal irreversibility has been investigated.

  6. Optimizing Antibiotic Dosing Strategies for the Treatment of Gram-negative Infections in the Era of Resistance.

    Science.gov (United States)

    Monogue, Marguerite L; Kuti, Joseph L; Nicolau, David P

    2016-01-01

    Gram-negative organisms are an increasing source of concern within the healthcare setting due to their common presence as a cause of infection and emerging resistance to current therapies. However, current antimicrobial dosing recommendations may be insufficient for the treatment of gram-negative infections. Applying knowledge of an antibiotic's pharmacokinetic/pharmacodynamic profile when designing a dosing regimen leads to a greater likelihood of achieving optimal exposure, including against gram-negative pathogens with higher MICs. Additionally, administering antibiotics directly to the site of infection, such as via aerosolization for pneumonia, is another method to achieve optimized drug exposure at the site of infection. Incorporating these treatment strategies into clinical practice will assist antimicrobial stewardship programs in successfully treating gram-negative infections.

  7. Economic Load Dispatch - A Comparative Study on Heuristic Optimization Techniques With an Improved Coordinated Aggregation-Based PSO

    DEFF Research Database (Denmark)

    Vlachogiannis, Ioannis (John); Lee, KY

    2009-01-01

    In this paper an improved coordinated aggregation-based particle swarm optimization (ICA-PSO) algorithm is introduced for solving the optimal economic load dispatch (ELD) problem in power systems. In the ICA-PSO algorithm each particle in the swarm retains a memory of its best position ever...... and the particles search the decision space with accuracy up to two digit points resulting in the improved convergence of the process. The ICA-PSO algorithm is tested on a number of power systems, including the systems with 6, 13, 15, and 40 generating units, the island power system of Crete in Greece...... and the Hellenic bulk power system, and is compared with other state-of-the-art heuristic optimization techniques (HOTs), demonstrating improved performance over them....

  8. SU-E-T-284: Dose Plan Optimization When Using Hydrogel Prostate-Rectum Spacer: A Single Institution Experience

    Energy Technology Data Exchange (ETDEWEB)

    Rajecki, M; Thurber, A; Catalfamo, F; Duff, M; Shah, D [Cancer Care of Western New York, Cheektowaga, NY (United States)

    2015-06-15

    Purpose: To describe rectal dose reduction achieved and techniques used to take advantage of the increased peri-rectal spacing provided by injected polyethylene-glycol. Methods: Thirty prostate cancer patents were 2:1 randomized during a clinical trial to evaluate the effectiveness of injected poly-ethylene glycol hydrogel (SpaceOAR System) in creating space between the prostate and the anterior rectal wall. All patients received a baseline CT/MR scan and baseline IMRT treatment plan. Patients were randomized to receive hydrogel injection (n=20) or Control (n=10), followed by another CT/MR scan and treatment plan (single arc VMAT, 6 MV photons, 79.2 Gy, 44 fractions). Additional optimization structures were employed to constrain the dose to the rectum; specifically an avoidance structure to limit V75 <15%, and a control structure to limit the maximum relative dose <105% in the interface region of the anterior rectal wall and the prostate planning target volume. Dose volumetric data was analyzed for rectal volumes receiving 60 through 80 Gy. Results: Rectal dose reduction was observed in all patients who received the hydrogel. Volumetric analysis indicates a median rectal volume and (reduction from baseline plan) following spacer application of 4.9% (8.9%) at V60Gy, 3.8% (8.1%) at V65Gy, 2.5% (7.2%) at V70Gy, 1.6% (5.8%) at V75Gy, and 0.5% (2.5%) at V80Gy. Conclusion: Relative to planning without spacers, rectal dose constraints of 5%, 4%, 3%, 2%, 1% for V60, V65, V70, V75, and V80, should be obtainable when peri-rectal spacers are used. The combined effect of increased peri-rectal space provided by the hydrogel, with strict optimization objectives, resulted in reduced dose to the rectum. To maximize benefit, strict optimization objectives and reduced rectal dose constraints should be employed when creating plans for patients with perirectal spacers. Clinical Trial for SpaceOAR product conducted by Augmenix,Inc. The research site was paid to be a participating site.

  9. Optimization & Design of High Rise Building with Different Structural Framing Systems Subjected To Seismic Loads

    Directory of Open Access Journals (Sweden)

    Mr. Anant A. Kapse ,

    2014-06-01

    Full Text Available Due to excessive displacements of tall buildings occasioned by lateral loads, lateral load resisting systems are usually provided to curtail the load effect. The resistance may be offered by Frame Action, Shear Walls, or combined Walls and Frames (also known as Dual System. In this study, 3D structural modelling base software STAAD-PRO was used to generate and analyze three-dimensional building models for the assessment of the relative effectiveness of the various lateral load resisting systems. Five models were used, one for moment resisting frame & 04 models each for the lateral load resisting systems. Each model consisted of G +10 storey frame structure having total height of 33.0 m. Each building sample was subjected to three-dimensional analysis for the determination of both the lateral displacements at storey top and interstorey drifts. The results of the work showed that the dual system was the most efficient lateral-load resisting system based on deflection criterion, as they yielded the least values for lateral displacements and inter-storey drifts. The moment frame was the least stiff of the resisting systems, yielding the highest values of both the lateral displacement and the inter-storey drift.

  10. Designing load frequency controller for interconnected power system using seeker optimization algorithm considering governor dead-band

    Directory of Open Access Journals (Sweden)

    M. Joorabian

    2014-07-01

    Full Text Available The Seeker Optimization Algorithm (SOA, as it is called now, is currently gaining popularity in the community of researchers, for its effectiveness in solving certain difficult real world optimization problems. This paper proposes SOA based Load Frequency Control (LFC for the suppression of oscillations in power system. A two area system and four area system deregulated is considered to be equipped with proportional plus integral (PI controllers. SOA is employed to search for optimal controller parameters by minimizing the time domain objective function. The performance of the proposed controller has been evaluated with the performance of the conventional PI controller and PI controller tuned by Particle Swarm Optimization (PSO and Bacterial Foraging Algorithm (BFA in order to demonstrate the superior efficiency of the proposed SOA in tuning PI controller. Simulation results emphasis on the better performance of the optimized PI controller based on SOA in compare to optimized PI controller based on PSO and BFA and conventional one over wide range of operating conditions, and system parameters variations.

  11. Research and Application on a Novel Clustering Algorithm of Quantum Optimization in Server Load Balancing

    Directory of Open Access Journals (Sweden)

    Dong Yumin

    2014-01-01

    Full Text Available A quantum optimization scheme in network cluster server task scheduling is proposed. We explore and research the distribution theory of energy field in quantum mechanics; specially, we apply it to data clustering. We compare the quantum optimization method with genetic algorithm (GA, ant colony optimization (ACO, simulated annealing algorithm (SAA. At the same time, we prove its validity and rationality by analog simulation and experiment.

  12. Chilled ceiling displacement ventilation design charts correlations to employ in optimized system operation for feasible load ranges

    Energy Technology Data Exchange (ETDEWEB)

    Keblawi, A.; Ghaddar, N.; Ghali, K. [Department of Mechanical Engineering, Faculty of Engineering and Architecture, American University of Beirut, P.O. Box 11-236, Riad El Solh, Beirut 1107 2020 (Lebanon); Jensen, L. [Department of Building Services Engineering, Lund University, Lund (Sweden)

    2009-11-15

    This paper expands Ghaddar et al. [N. Ghaddar, K. Ghali, R. Saadeh, A. Keblawi, Design charts for combined chilled ceiling displacement ventilation system (1438-RP), ASHRAE Transactions, 143 (2) (2008) 574-587] design charts of combined chilled ceiling (CC) displacement ventilation (DV) system to operating sensible load ranges from 40 W/m{sup 2} to 100 W/m{sup 2}. It develops a global correlation of system load and operational parameters, with comfort measured by vertical temperature gradient and indoor air quality measured by the stratification height. The correlations are used for a known transient load profile in generating optimal settings of the CC/DV system operational parameters and associated energy consumption. An example is illustrated to show how the correlation could be used to size the system and to provide optimized control of the CC/DV system operation at low computational cost. Results of the current model are compared to the published case study of an optimized operation based on transient simulations of the space thermal model to achieve minimum operation cost [M. Mossolly, N. Ghaddar, K. Ghali, L. Jensen, Optimized operation of combined chilled ceiling displacement ventilation system using genetic algorithm, ASHRAE Transactions, 143 (2) (2008) 541-554]. The design correlations resulted in good agreement with published data (within 3% error in energy consumption and average 6% error in predictions of comfort and stratification height) at 1/4 of the computational time. The presented methodology provides an alternative for using the correlation for supervisory online controllers for the CC/DV system based on physically derived correlations. (author)

  13. Quality by design approach for formulation, evaluation and statistical optimization of diclofenac-loaded ethosomes via transdermal route.

    Science.gov (United States)

    Jain, Shashank; Patel, Niketkumar; Madan, Parshotam; Lin, Senshang

    2015-06-01

    The objective of this study was to fabricate and understand ethosomal formulations of diclofenac (DF) for enhanced anti-inflammatory activity using quality by design approach. DF-loaded ethosomal formulations were prepared using 4 × 5 full-factorial design with phosphatidylcholine:cholesterol (PC:CH) ratios ranging between 50:50 and 90:10, and ethanol concentration ranging between 0% and 30% as formulation variables. These formulations were characterized in terms of physicochemical properties and skin permeation kinetics. The interaction of formulation variables had a significant effect on both physicochemical properties and permeation kinetics. The results of multivariate regression analysis illustrated that vesicle size and elasticity of ethosomes were the dominating physicochemical properties affecting skin permeation, and could be suitably controlled by manipulation of formulation variables to optimize the formulation and enhance the skin permeation of DF-loaded ethosomes. The optimized formulation had ethanol concentration of 22.9% and PC:CH ratio of 88.4:11.6, with vesicle size of 144 ± 5 nm, zeta potential of -23.0 ± 3.76 mV, elasticity of 2.48 ± 0.75 and entrapment efficiency of 71 ± 4%. Permeation flux for the optimized formulation was 12.9 ± 1.0 µg/h cm(2), which was significantly higher than the drug-loaded conventional liposome, ethanolic or aqueous solution. The in vivo study indicated that optimized ethosomal hydrogel exhibited enhanced anti-inflammatory activity compared with liposomal and plain drug hydrogel formulations.

  14. [Optimal dose of midazolam as premedicant for combined spinal and epidural anesthesia with midazolam sedation].

    Science.gov (United States)

    Tabuchi, Y

    1992-04-01

    Sixty patients who underwent simple total hysterectomy under combined spinal and epidural anesthesia with midazolam sedation, were the subjects of a randomized double-blind comparison of intramuscular midazolam 4, 4.5 and 5 mg, and a dose determined by body weight as premedicants. Similar changes in arterial pressure and heart rate were observed. Furthermore sedation and the value of pulse oximetry on arrival were the same. Besides half the patients were amnesic during the procedure of regional approach. However the dose of premedicant was inversely correlated with the maintenance dose. The reduction of pulse oximetry reading on the induction was smaller, while the requirement of vasopressor occurred earlier following the larger dose of premedicant. In spite of the slower induction, the fall of pulse oximetry reading did not decrease. One hour after incision, the reduction of PaO2 was not dose related. In addition count of leucocyte and the level of blood glucose were unchanged. Premedicant determined by body weight was not correlated with the induction dose and amnesic effect. Our findings suggest midazolam 5 mg intramuscularly is the more preferable dose, but careful attention on arterial pressure is required.

  15. Prediction of Optimal Reversal Dose of Sugammadex after Rocuronium Administration in Adult Surgical Patients

    Directory of Open Access Journals (Sweden)

    Shigeaki Otomo

    2014-01-01

    Full Text Available The objective of this study was to determine the point after sugammadex administration at which sufficient or insufficient dose could be determined, using first twitch height of train-of-four (T1 height or train-of-four ratio (TOFR as indicators. Groups A and B received 1 mg/kg and 0.5 mg/kg of sugammadex, respectively, as a first dose when the second twitch reappeared in train-of-four stimulation, and Groups C and D received 1 mg/kg and 0.5 mg/kg of sugammadex, respectively, as the first dose at posttetanic counts 1–3. Five minutes after the first dose, an additional 1 mg/kg of sugammadex was administered and changes in T1 height and TOFR were observed. Patients were divided into a recovered group and a partly recovered group, based on percentage changes in T1 height after additional dosing. T1 height and TOFR during the 5 min after first dose were then compared. In the recovered group, TOFR exceeded 90% in all patients at 3 min after sugammadex administration. In the partly recovered group, none of the patients had a TOFR above 90% at 3 min after sugammadex administration. An additional dose of sugammadex can be considered unnecessary if the train-of-four ratio is ≥90% at 3 min after sugammadex administration. This trial is registered with UMIN000007245.

  16. Prediction of Optimal Reversal Dose of Sugammadex after Rocuronium Administration in Adult Surgical Patients

    Science.gov (United States)

    Iwasaki, Hiroshi

    2014-01-01

    The objective of this study was to determine the point after sugammadex administration at which sufficient or insufficient dose could be determined, using first twitch height of train-of-four (T1 height) or train-of-four ratio (TOFR) as indicators. Groups A and B received 1 mg/kg and 0.5 mg/kg of sugammadex, respectively, as a first dose when the second twitch reappeared in train-of-four stimulation, and Groups C and D received 1 mg/kg and 0.5 mg/kg of sugammadex, respectively, as the first dose at posttetanic counts 1–3. Five minutes after the first dose, an additional 1 mg/kg of sugammadex was administered and changes in T1 height and TOFR were observed. Patients were divided into a recovered group and a partly recovered group, based on percentage changes in T1 height after additional dosing. T1 height and TOFR during the 5 min after first dose were then compared. In the recovered group, TOFR exceeded 90% in all patients at 3 min after sugammadex administration. In the partly recovered group, none of the patients had a TOFR above 90% at 3 min after sugammadex administration. An additional dose of sugammadex can be considered unnecessary if the train-of-four ratio is ≥90% at 3 min after sugammadex administration. This trial is registered with UMIN000007245. PMID:24672542

  17. Optimization of foramsulfuron doses for post-emergence weed control in maize (Zea mays L.)

    Energy Technology Data Exchange (ETDEWEB)

    Pannacci, E.

    2016-11-01

    Four field experiments were carried out from 2011 to 2014 in order to evaluate the effects of foramsulfuron, applied at the recommended (60.8 g a.i./ha) and reduced doses (1/3 and 2/3), on the efficacy against several of the most important weeds in maize. For each “year-weed” combination, dose-response curves were applied to estimate the dose of foramsulfuron required to obtain 90% and 95% weed control (ED90 and ED95). Foramsulfuron phytotoxicity on maize and crop yield were assessed. Foramsulfuron at 1/3 of the recommended dose (20.3 g a.i./ha) provided 95% efficacy against redroot pigweed (Amaranthus retroflexus L.), green foxtail (Setaria viridis (L.) Beauv.), wild mustard (Sinapis arvensis L.) and black nightshade (Solanum nigrum L.). Velvetleaf (Abutilon theophrasti Medik.), common lambsquarters (Chenopodium album L.) and barnyardgrass (Echinochloa crus-galli (L.) Beauv.) were satisfactorily controlled (95% weed efficacy) with ED95 ranged from 20 to 50 g/ha of foramsulfuron (about from 1/3 to 5/6 of the recommended dose) depending on growth stage. The recommended dose was effective against pale smartweed (Polygonum lapathifolium L.) at 2-4 true leaves (12-14 BBCH scale), but this dose did not kill plants larger than 2-4 true leaves. The ranking among weed species based on their susceptibility to foramsulfuron was: redroot pigweed = green foxtail = wild mustard = black nightshade > velvetleaf = common lambsquarters = barnyardgrass > pale smartweed. Dose of foramsulfuron can be reduced below recommended dose depending on weed species and growth stage. Foramsulfuron showed a good crop selectivity and had no negative effect on maize yield. (Author)

  18. Optimization of foramsulfuron doses for post-emergence weed control in maize (Zea mays L.

    Directory of Open Access Journals (Sweden)

    Euro Pannacci

    2016-08-01

    Full Text Available Four field experiments were carried out from 2011 to 2014 in order to evaluate the effects of foramsulfuron, applied at the recommended (60.8 g a.i./ha and reduced doses (1/3 and 2/3, on the efficacy against several of the most important weeds in maize. For each “year-weed” combination, dose-response curves were applied to estimate the dose of foramsulfuron required to obtain 90% and 95% weed control (ED90 and ED95. Foramsulfuron phytotoxicity on maize and crop yield were assessed. Foramsulfuron at 1/3 of the recommended dose (20.3 g a.i./ha provided 95% efficacy against redroot pigweed (Amaranthus retroflexus L., green foxtail (Setaria viridis (L. Beauv., wild mustard (Sinapis arvensis L. and black nightshade (Solanum nigrum L.. Velvetleaf (Abutilon theophrasti Medik., common lambsquarters (Chenopodium album L. and barnyardgrass (Echinochloa crus-galli (L. Beauv. were satisfactorily controlled (95% weed efficacy with ED95 ranged from 20 to 50 g/ha of foramsulfuron (about from 1/3 to 5/6 of the recommended dose depending on growth stage. The recommended dose was effective against pale smartweed (Polygonum lapathifolium L. at 2-4 true leaves (12-14 BBCH scale, but this dose did not kill plants larger than 2-4 true leaves. The ranking among weed species based on their susceptibility to foramsulfuron was: redroot pigweed = green foxtail = wild mustard = black nightshade > velvetleaf = common lambsquarters = barnyardgrass > pale smartweed. Dose of foramsulfuron can be reduced below recommended dose depending on weed species and growth stage. Foramsulfuron showed a good crop selectivity and had no negative effect on maize yield.

  19. Which genetic determinants should be considered for tacrolimus dose optimization in kidney transplantation?

    DEFF Research Database (Denmark)

    Bruckmueller, H; Werk, Anneke Nina; Renders, Lutz

    2014-01-01

    BACKGROUND:: Tacrolimus is established as immunosuppressant after kidney transplantation. Polymorphism of the cytochrome P450 3A5 (CYP3A5) gene contributes significantly to tacrolimus dose requirements. Recently, CYP3A4*22 was reported to additionally affect tacrolimus pharmacokinetics (PK). In a...... remains essential in clinical care of kidney transplant patients. Genotyping of CYP3A5 and CYP3A4, however, could facilitate rapid dose finding to adapt the appropriate immunosuppressant dose, whereas other genetic factors had only little or no effect....

  20. Preparation, characterization, and optimization of primaquine-loaded solid lipid nanoparticles

    OpenAIRE

    Omwoyo, Wesley Nyaigoti; Ogutu, Bernhards; Oloo,Florence; Swai,Hulda; Kalombo, Lonji; Melariri, Paula; Mahanga, Geoffrey Maroa; Gathirwa, Jeremiah Waweru

    2014-01-01

    Primaquine (PQ) is one of the most widely used antimalarial drugs and is the only available drug that combats the relapsing form of malaria. PQ use in higher doses is limited by severe tissue toxicity including hematological- and gastrointestinal-related side effects. Nanoformulation of drugs in an appropriate drug carrier system has been extensively studied and shown to have the potential to improve bioavailability, thereby enhancing activity, reducing dose frequency, and subsequently reduci...

  1. Cost-based Optimal Distributed Generation Planning with Considering Voltage Depended Loads and Power Factor of Distributed Generation

    Directory of Open Access Journals (Sweden)

    Babak Yousefi-Khangah

    2014-12-01

    Full Text Available If determination of location and size of Distributed Generation (DG are applied accurately, the DG’s ability will improve the network situation and reduce operation costs. In this paper, various market conditions are considered to maximize the benefit of DG’s presence and make a trade off among advantages of DG, network situation, and Distribution Company (DISCO owners. To determine the optimal location and size of DG, two methods of the cost minimization and the nodal pricing are combined. In addition to evaluating the impact of parameters such as variation of energy price and load on objective function, effect of these parameters on location and size of DG is considered. To confirm the results, impact of loads which are dependent on voltage and variation of the power factor of the DG units is applied and then effect of power factor on optimal location and size of DG is shown. A method is proposed for convergence of different results which is caused by different power factors. To observe long-term impact of the DG’s presence in the network, a load growth for five years is considered annually. Study is carried out on IEEE30 bus test circuit.

  2. Optimization of image quality and dose for Varian aS500 electronic portal imaging devices (EPIDs).

    Science.gov (United States)

    McGarry, C K; Grattan, M W D; Cosgrove, V P

    2007-12-07

    This study was carried out to investigate whether the electronic portal imaging (EPI) acquisition process could be optimized, and as a result tolerance and action levels be set for the PIPSPro QC-3V phantom image quality assessment. The aim of the optimization process was to reduce the dose delivered to the patient while maintaining a clinically acceptable image quality. This is of interest when images are acquired in addition to the planned patient treatment, rather than images being acquired using the treatment field during a patient's treatment. A series of phantoms were used to assess image quality for different acquisition settings relative to the baseline values obtained following acceptance testing. Eight Varian aS500 EPID systems on four matched Varian 600C/D linacs and four matched Varian 2100C/D linacs were compared for consistency of performance and images were acquired at the four main orthogonal gantry angles. Images were acquired using a 6 MV beam operating at 100 MU min(-1) and the low-dose acquisition mode. Doses used in the comparison were measured using a Farmer ionization chamber placed at d(max) in solid water. The results demonstrated that the number of reset frames did not have any influence on the image contrast, but the number of frame averages did. The expected increase in noise with corresponding decrease in contrast was also observed when reducing the number of frame averages. The optimal settings for the low-dose acquisition mode with respect to image quality and dose were found to be one reset frame and three frame averages. All patients at the Northern Ireland Cancer Centre are now imaged using one reset frame and three frame averages in the 6 MV 100 MU min(-1) low-dose acquisition mode. Routine EPID QC contrast tolerance (+/-10) and action (+/-20) levels using the PIPSPro phantom based around expected values of 190 (Varian 600C/D) and 225 (Varian 2100C/D) have been introduced. The dose at dmax from electronic portal imaging has been

  3. Active and Reactive Power Optimal Dispatch Associated with Load and DG Uncertainties in Active Distribution Network

    Science.gov (United States)

    Gao, F.; Song, X. H.; Zhang, Y.; Li, J. F.; Zhao, S. S.; Ma, W. Q.; Jia, Z. Y.

    2017-05-01

    In order to reduce the adverse effects of uncertainty on optimal dispatch in active distribution network, an optimal dispatch model based on chance-constrained programming is proposed in this paper. In this model, the active and reactive power of DG can be dispatched at the aim of reducing the operating cost. The effect of operation strategy on the cost can be reflected in the objective which contains the cost of network loss, DG curtailment, DG reactive power ancillary service, and power quality compensation. At the same time, the probabilistic constraints can reflect the operation risk degree. Then the optimal dispatch model is simplified as a series of single stage model which can avoid large variable dimension and improve the convergence speed. And the single stage model is solved using a combination of particle swarm optimization (PSO) and point estimate method (PEM). Finally, the proposed optimal dispatch model and method is verified by the IEEE33 test system.

  4. Imatinib in the treatment of chronic myeloid leukemia: current perspectives on optimal dose

    Directory of Open Access Journals (Sweden)

    Waclaw J

    2015-09-01

    Full Text Available Joanna Waclaw,1 Tomasz Sacha,1 Tomasz Stoklosa,21Department of Hematology, Jagiellonian University Collegium Medicum, Kraków, 2Department of Immunology, Medical University of Warsaw, Warsaw, Poland Abstract: Imatinib was the first tyrosine kinase inhibitor (TKI, successfully used in a clinical setting. It inhibits activity of BCR-ABL1 oncogenic tyrosine kinase which is crucial in the pathogenesis of chronic myeloid leukemia (CML. The safety and efficacy of imatinib dose 400 mg daily was established in several clinical studies. Nevertheless, imatinib dose escalation (≥600 mg daily has been widely explored as an option to improve clinical outcomes. Results of the meta-analysis comparing frontline therapy with imatinib 400 mg daily vs high dose (HD, ≥600 mg daily in patients with chronic phase CML (CML-CP showed that the rate of complete cytogenetic response as well as major molecular response (MMR at 12 months was significantly higher in HD imatinib group. However, HD imatinib does not improve overall survival and progression-free survival. Thus, the routine use of HD imatinib as frontline treatment for CML-CP is not recommended. In patients with CML-CP resistant to standard dose, HD imatinib does not significantly improve patient outcomes without a prior cytogenetic response. Therefore, in second-line therapy, the current CML-CP treatment guidelines do not recommend imatinib dose escalation but the use of second-or third-generation TKIs. In the therapy of TKI-naïve patients with accelerated or blastic phase of CML, HD imatinib (400 mg twice daily is one of the recommended standards. In case of disease progression while on imatinib, second- or third-generation TKIs should be administered. Keywords: imatinib, standard dose, dose escalation, chronic myeloid leukemia, BCR-ABL1, high dose

  5. Optimizing the spatial distribution of dose in X-ray macromolecular crystallography.

    Science.gov (United States)

    Zeldin, Oliver B; Gerstel, Markus; Garman, Elspeth F

    2013-01-01

    X-ray data collection for macromolecular crystallography can lead to highly inhomogeneous distributions of dose within the crystal volume for cases when the crystal is larger than the beam or when the beam is non-uniform (gaussian-like), particularly when crystal rotation is fully taken into account. Here the spatial distribution of dose is quantitatively modelled in order to compare the effectiveness of two dose-spreading data-collection protocols: helical scanning and translational collection. Their effectiveness in reducing the peak dose per unit diffraction is investigated via simulations for four common crystal shapes (cube, plate, long and short needles) and beams with a wide range of full width half maximum values. By inspection of the chosen metric, it is concluded that the optimum strategy is always to use as flat (top-hat) a beam as possible and to either match the beam size in both dimensions to the crystal, or to perform a helical scan with a beam which is narrow along the rotation axis and matched to the crystal size along the perpendicular axis. For crystal shapes where this is not possible, the reduction in peak dose per unit diffraction achieved through dose spreading is quantified and tabulated as a reference for experimenters.

  6. Short-term bulk energy storage system scheduling for load leveling in unit commitment: modeling, optimization, and sensitivity analysis.

    Science.gov (United States)

    Hemmati, Reza; Saboori, Hedayat

    2016-05-01

    Energy storage systems (ESSs) have experienced a very rapid growth in recent years and are expected to be a promising tool in order to improving power system reliability and being economically efficient. The ESSs possess many potential benefits in various areas in the electric power systems. One of the main benefits of an ESS, especially a bulk unit, relies on smoothing the load pattern by decreasing on-peak and increasing off-peak loads, known as load leveling. These devices require new methods and tools in order to model and optimize their effects in the power system studies. In this respect, this paper will model bulk ESSs based on the several technical characteristics, introduce the proposed model in the thermal unit commitment (UC) problem, and analyze it with respect to the various sensitive parameters. The technical limitations of the thermal units and transmission network constraints are also considered in the model. The proposed model is a Mixed Integer Linear Programming (MILP) which can be easily solved by strong commercial solvers (for instance CPLEX) and it is appropriate to be used in the practical large scale networks. The results of implementing the proposed model on a test system reveal that proper load leveling through optimum storage scheduling leads to considerable operation cost reduction with respect to the storage system characteristics.

  7. Enhanced Ungual Permeation of Terbinafine HCl Delivered Through Liposome-Loaded Nail Lacquer Formulation Optimized by QbD Approach.

    Science.gov (United States)

    Shah, Viral H; Jobanputra, Amee

    2017-07-05

    The present investigation focused on developing, optimizing, and evaluating a novel liposome-loaded nail lacquer formulation for increasing the transungual permeation flux of terbinafine HCl for efficient treatment of onychomycosis. A three-factor, three-level, Box-Behnken design was employed for optimizing process and formulation parameters of liposomal formulation. Liposomes were formulated by thin film hydration technique followed by sonication. Drug to lipid ratio, sonication amplitude, and sonication time were screened as independent variables while particle size, PDI, entrapment efficiency, and zeta potential were selected as quality attributes for liposomal formulation. Multiple regression analysis was employed to construct a second-order quadratic polynomial equation and contour plots. Design space (overlay plot) was generated to optimize a liposomal system, with software-suggested levels of independent variables that could be transformed to desired responses. The optimized liposome formulation was characterized and dispersed in nail lacquer which was further evaluated for different parameters. Results depicted that the optimized terbinafine HCl-loaded liposome formulation exhibited particle size of 182 nm, PDI of 0.175, zeta potential of -26.8 mV, and entrapment efficiency of 80%. Transungual permeability flux of terbinafine HCl through liposome-dispersed nail lacquer formulation was observed to be significantly higher in comparison to nail lacquer with a permeation enhancer. The developed formulation was also observed to be as efficient as pure drug dispersion in its antifungal activity. Thus, it was concluded that the developed formulation can serve as an efficient tool for enhancing the permeability of terbinafine HCl across human nail plate thereby improving its therapeutic efficiency.

  8. Preparation and Optimization of Triptolide-Loaded Solid Lipid Nanoparticles for Oral Delivery with Reduced Gastric Irritation

    Directory of Open Access Journals (Sweden)

    Xiangliang Yang

    2013-10-01

    Full Text Available Triptolide (TP often causes adverse reactions in the gastrointestinal tract when it is administered orally. This study aimed to prepare and optimize triptolide-loaded solid lipid nanoparticles (TP-SLN with reduced gastric irritation. The microemulsion technique was used to formulate TP-SLN employing a five-level central composite design (CCD that was developed for exploring the optimum levels of three independent variables on particle size, encapsulation efficiency (EE and drug loading (DL. Quadratic polynomial models were generated to predict and evaluate the three independent variables with respect to the three responses. The optimized TP-SLN was predicted to comprise fraction of lipid of 49.73%, surfactant to co-surfactant ratio of 3.25, and lipid to drug ratio of 55.27, which showed particle size of 179.8 ± 5.7 nm, EE of 56.5 ± 0.18% and DL of 1.02 ± 0.003% that were in good agreement with predicted values. In addition, the optimized nanoparticles manifested a sustained-release pattern in vitro and were stable during 3 h of incubation in simulated gastric fluids without significant size change and the majority (91% of the drug was protected. Furthermore, the nanoparticles did not show obvious gastric irritation caused by oral administration of TP in rats.

  9. Annual Electric Load Forecasting by a Least Squares Support Vector Machine with a Fruit Fly Optimization Algorithm

    Directory of Open Access Journals (Sweden)

    Bao Wang

    2012-11-01

    Full Text Available The accuracy of annual electric load forecasting plays an important role in the economic and social benefits of electric power systems. The least squares support vector machine (LSSVM has been proven to offer strong potential in forecasting issues, particularly by employing an appropriate meta-heuristic algorithm to determine the values of its two parameters. However, these meta-heuristic algorithms have the drawbacks of being hard to understand and reaching the global optimal solution slowly. As a novel meta-heuristic and evolutionary algorithm, the fruit fly optimization algorithm (FOA has the advantages of being easy to understand and fast convergence to the global optimal solution. Therefore, to improve the forecasting performance, this paper proposes a LSSVM-based annual electric load forecasting model that uses FOA to automatically determine the appropriate values of the two parameters for the LSSVM model. By taking the annual electricity consumption of China as an instance, the computational result shows that the LSSVM combined with FOA (LSSVM-FOA outperforms other alternative methods, namely single LSSVM, LSSVM combined with coupled simulated annealing algorithm (LSSVM-CSA, generalized regression neural network (GRNN and regression model.

  10. Development, optimization and in vitro-in vivo evaluation of pioglitazone- loaded jackfruit seed starch-alginate beads.

    Science.gov (United States)

    Nayak, Amit Kumar; Pal, Dilipkumar; Hasnain, Saquib Md

    2013-10-01

    The present investigation describes development and optimization of pioglitazone-loaded jackfruit seed starch (JFSS)-alginate beads by ionotropic-gelation using 3(2) factorial design. The effect of polymer-blend ratio and CaCl2 concentration on the drug encapsulation efficiency (DEE, %), and cumulative drug release after 10 hours (R10h, %) was optimized. The DEE (%) of these beads were 64.80 ± 1.92 to 94.07 ± 3.82 % with sustained in vitro drug release of 64.± 1.83 to 92.66 ± 4.54 % over 10 hours. The in vitro drug release from these beads followed controlled-release pattern with super case-II transport. Particle size range of these beads was 0.77 ± 0.04 to 1.24 ± 0.09 mm. The beads were also characterized by SEM and FTIR. The swelling of these beads was influenced by pH of the test medium. The optimized pioglitazone-loaded JFSS-alginate beads showed significant hypoglycemic effect in alloxan-induced diabetic rats over prolonged period after oral administration.

  11. WE-B-304-02: Treatment Planning Evaluation and Optimization Should Be Biologically and Not Dose/volume Based

    Energy Technology Data Exchange (ETDEWEB)

    Deasy, J. [Memorial Sloan Kettering Cancer Center, New York, NY (United States)

    2015-06-15

    The ultimate goal of radiotherapy treatment planning is to find a treatment that will yield a high tumor control probability (TCP) with an acceptable normal tissue complication probability (NTCP). Yet most treatment planning today is not based upon optimization of TCPs and NTCPs, but rather upon meeting physical dose and volume constraints defined by the planner. It has been suggested that treatment planning evaluation and optimization would be more effective if they were biologically and not dose/volume based, and this is the claim debated in this month’s Point/Counterpoint. After a brief overview of biologically and DVH based treatment planning by the Moderator Colin Orton, Joseph Deasy (for biological planning) and Charles Mayo (against biological planning) will begin the debate. Some of the arguments in support of biological planning include: this will result in more effective dose distributions for many patients DVH-based measures of plan quality are known to have little predictive value there is little evidence that either D95 or D98 of the PTV is a good predictor of tumor control sufficient validated outcome prediction models are now becoming available and should be used to drive planning and optimization Some of the arguments against biological planning include: several decades of experience with DVH-based planning should not be discarded we do not know enough about the reliability and errors associated with biological models the radiotherapy community in general has little direct experience with side by side comparisons of DVH vs biological metrics and outcomes it is unlikely that a clinician would accept extremely cold regions in a CTV or hot regions in a PTV, despite having acceptable TCP values Learning Objectives: To understand dose/volume based treatment planning and its potential limitations To understand biological metrics such as EUD, TCP, and NTCP To understand biologically based treatment planning and its potential limitations.

  12. WE-B-304-01: Treatment Planning Evaluation and Optimization Should Be Dose/volume and Not Biologically Based

    Energy Technology Data Exchange (ETDEWEB)

    Mayo, C. [Mayo Clinic (United States)

    2015-06-15

    The ultimate goal of radiotherapy treatment planning is to find a treatment that will yield a high tumor control probability (TCP) with an acceptable normal tissue complication probability (NTCP). Yet most treatment planning today is not based upon optimization of TCPs and NTCPs, but rather upon meeting physical dose and volume constraints defined by the planner. It has been suggested that treatment planning evaluation and optimization would be more effective if they were biologically and not dose/volume based, and this is the claim debated in this month’s Point/Counterpoint. After a brief overview of biologically and DVH based treatment planning by the Moderator Colin Orton, Joseph Deasy (for biological planning) and Charles Mayo (against biological planning) will begin the debate. Some of the arguments in support of biological planning include: this will result in more effective dose distributions for many patients DVH-based measures of plan quality are known to have little predictive value there is little evidence that either D95 or D98 of the PTV is a good predictor of tumor control sufficient validated outcome prediction models are now becoming available and should be used to drive planning and optimization Some of the arguments against biological planning include: several decades of experience with DVH-based planning should not be discarded we do not know enough about the reliability and errors associated with biological models the radiotherapy community in general has little direct experience with side by side comparisons of DVH vs biological metrics and outcomes it is unlikely that a clinician would accept extremely cold regions in a CTV or hot regions in a PTV, despite having acceptable TCP values Learning Objectives: To understand dose/volume based treatment planning and its potential limitations To understand biological metrics such as EUD, TCP, and NTCP To understand biologically based treatment planning and its potential limitations.

  13. Power performance optimization and loads alleviation with active flaps using individual flap control

    DEFF Research Database (Denmark)

    Pettas, Vasilis; Barlas, Athanasios; Gertz, Drew Patrick;

    2016-01-01

    The present article investigates the potential of Active Trailing Edge Flaps (ATEF) in terms of increase in annual energy production (AEP) as well as reduction of fatigue loads. The basis for this study is the DTU 10 MW Reference Wind Turbine (RWT) simulated using the aeroelastic code HAWC2...... the sensor inputs. The AEP is increased due to the upscaling but also further due to the flap system while the fatigue loads in components of interest (blade, tower, nacelle and main bearing) are reduced close to the level of the original turbine. The aim of this study is to demonstrate a simple...

  14. Design and Optimization of a Composite Canard Control Surface of an Advanced Fighter Aircraft under Static Loading

    Directory of Open Access Journals (Sweden)

    Shrivastava Sachin

    2015-01-01

    Full Text Available The minimization of weight and maximization of payload is an ever challenging design procedure for air vehicles. The present study has been carried out with an objective to redesign control surface of an advanced all-metallic fighter aircraft. In this study, the structure made up of high strength aluminum, titanium and ferrous alloys has been attempted to replace by carbon fiber composite (CFC skin, ribs and stiffeners. This study presents an approach towards development of a methodology for optimization of first-ply failure index (FI in unidirectional fibrous laminates using Genetic-Algorithms (GA under quasi-static loading. The GAs, by the application of its operators like reproduction, cross-over, mutation and elitist strategy, optimize the ply-orientations in laminates so as to have minimum FI of Tsai-Wu first-ply failure criterion. The GA optimization procedure has been implemented in MATLAB and interfaced with commercial software ABAQUS using python scripting. FI calculations have been carried out in ABAQUS with user material subroutine (UMAT. The GA's application gave reasonably well-optimized ply-orientations combination at a faster convergence rate. However, the final optimized sequence of ply-orientations is obtained by tweaking the sequences given by GA's based on industrial practices and experience, whenever needed. The present study of conversion of an all metallic structure to partial CFC structure has led to 12% of weight reduction. Therefore, the approach proposed here motivates designer to use CFC with a confidence.

  15. TU-EF-204-09: A Preliminary Method of Risk-Informed Optimization of Tube Current Modulation for Dose Reduction in CT

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Y; Liu, B; Kalra, M; Caracappa, P [Rensselaer Polytechnic Institute, Troy, NY (United States); Liu, T; Li, X [Massachusetts General Hospital, Boston, MA (United States); Xu, X [Rensselaer Polytechnic Inst., Troy, NY (United States)

    2015-06-15

    Purpose: X-rays from CT scans can increase cancer risk to patients. Lifetime Attributable Risk of Cancer Incidence for adult patients has been investigated and shown to decrease as patient age. However, a new risk model shows an increasing risk trend for several radiosensitive organs for middle age patients. This study investigates the feasibility of a general method for optimizing tube current modulation (TCM) functions to minimize risk by reducing radiation dose to radiosensitive organs of patients. Methods: Organ-based TCM has been investigated in literature for eye lens dose and breast dose. Adopting the concept in organ-based TCM, this study seeks to find an optimized tube current for minimal total risk to breasts and lungs by reducing dose to these organs. The contributions of each CT view to organ dose are determined through simulations of CT scan view-by-view using a GPU-based fast Monte Carlo code, ARCHER. A Linear Programming problem is established for tube current optimization, with Monte Carlo results as weighting factors at each view. A pre-determined dose is used as upper dose boundary, and tube current of each view is optimized to minimize the total risk. Results: An optimized tube current is found to minimize the total risk of lungs and breasts: compared to fixed current, the risk is reduced by 13%, with breast dose reduced by 38% and lung dose reduced by 7%. The average tube current is maintained during optimization to maintain image quality. In addition, dose to other organs in chest region is slightly affected, with relative change in dose smaller than 10%. Conclusion: Optimized tube current plans can be generated to minimize cancer risk to lungs and breasts while maintaining image quality. In the future, various risk models and greater number of projections per rotation will be simulated on phantoms of different gender and age. National Institutes of Health R01EB015478.

  16. LOAD-CHECK, program supported optimization of the fuel element disposal in cask CASTOR {sup registered} V casks; LOAD-CHECK, programmunterstuetzte Optimierung der Brennelemententsorgung in CASTOR {sup registered} V-Behaeltern

    Energy Technology Data Exchange (ETDEWEB)

    Amian, D.; Braun, A. [WTI Wissenschaftlich-Technische Ingenieurberatung GmbH, Juelich (Germany); Graf, R.; Hoffmann, V. [GNS Gesellschaft fuer Nuklear-Service mbH, Essen (Germany)

    2010-05-15

    LOAD-CHECK is an interactive program module for the systematic and strategic spent fuel disposal planning. Using physical fuel element data the loading scenarios for the routine operation and the post-closure operation phase can be simulated for free selectable time periods. The basis for the loading license application are the available spent fuel casks according to the regulations of the interim storage facility. LOAD-CHECK allows the optimization of the loading campaigns with respect to the time schedule and the number of casks including the planning of optimized disposal of special spent fuel (MOX fuel elements or high-burnup fuel elements). Possibilities for a reduced post-closure operating phase of nuclear power plants might be the consequence.

  17. Effect of intensiti modulated radiation therapy according to equivalent uniform dose optimization method on patients with lung cancer

    Institute of Scientific and Technical Information of China (English)

    Yu-Fu Zhou; Qian Sun; Ya-Jun Zhang; Geng-Ming Wang; Bin He; Tao Qi; An Zhou

    2016-01-01

    Objective:To analyze the effect of the intensity modulated radiation therapy according to equivalent uniform dose optimization method on patients with lung cancer.Methods:A total of 82 cases of non-small cell lung cancer were divided into observation group and control group according to the random number table method. Patients in the control group received conventional radiotherapy while observation group received intensity modulated radiotherapy based on equivalent uniform dose optimization method. The treatment effects, survival times, blood vessel-related factors, blood coagulation function and the levels of inflammatory factors and so on were compared between the two groups of patients.Results:The effective rate of the observation group after treatment was higher than that of the control group. Progression free survival and median overall survival times were longer than those of patients in the control group (P<0.05). The serum VEGF and HIF-αα levels as well as D-D, TT, PT, APTT and FIB levels were lower in observation group patients after treatment than those in the control group(P<0.05). At the same time point, serum TNF-αα, CRP and PCT levels in the observation group after treatment were lower than those in the control group (P<0.05). Serum M2-PK, CA125, CEA and SCC values of patients in the observation group after treatment were all significantly lower than those in the control group (P< 0.05).Conclusions:Intensity modulated radiation therapy based on equivalent uniform dose optimized method can improve the treatment effect, prolong the survival time, optimize micro inflammatory environment and inhibit tumor biological behavior at the same time.

  18. Element stacking method for topology optimization with material-dependent boundary and loading conditions

    DEFF Research Database (Denmark)

    Yoon, Gil Ho; Park, Y.K.; Kim, Y.Y.

    2007-01-01

    A new topology optimization scheme, called the element stacking method, is developed to better handle design optimization involving material-dependent boundary conditions and selection of elements of different types. If these problems are solved by existing standard approaches, complicated finite...... element models or topology optimization reformulation may be necessary. The key idea of the proposed method is to stack multiple elements on the same discretization pixel and select a single or no element. In this method, stacked elements on the same pixel have the same coordinates but may have...

  19. Optimal compatible doses and effects of ephedrine and naloxone on neural plasticity in cerebral ischemia/reperfusion rats

    Institute of Scientific and Technical Information of China (English)

    Yuxia Chen; Nong Xiao; Xiaoping Zhang; Ling Liu; Liyun Lin; Siyuan Chen; Bei Xu

    2008-01-01

    BACKGROUND: Ephedrine promotes neural plasticity in rats following cerebral iscbemia/reperfusion injury. Ephedrine has been combined with naloxone in some studies, and it has been confirmed that their combination has synergistic effects on increasing neural plasticity following cerebral ischemia/reperfusion injury.OBJECTIVE: To investigate the effects of ephedrine combined with various doses of naloxone on neural plasticity and to find an optimal dose of naloxone in rats after cerebral ischemia/reperfusion injury by analyzing growth associated protein-43 (GAP-43), synaptophysin and β -endorphin expression in the hippocampal CA3 area.DESIGN, TIME AND SETTING: This immunohistochemical, randomized, controlled, animal experiment was performed at the Chongqing Research Institute of Pediatrics, China from September 2007 to June 2008.MATERIALS: Ephedrine hydrochloride injection and naloxone hydrochloride injection were respectively purchased from Shandong Lvliang Pharmaceutical Factory, China and Sichuan Jingwei Pharmaceutical Co.,Ltd., China. A total of 192 healthy adult Sprague Dawley rats were used to establish models of left middle cerebral artery occlusion using the suture occlusion method.METHODS: At 2 hours following cerebral ischemia, the rats were intraperitoneally injected with 1.5 mg/kg/d ephedrine (ephedrine group), with 0.1, 0.2, or 0.3 mg/kg/d naloxone (low, moderate and high doses of naloxone groups), with 1.5 mg/kg/d ephedrine + 0. 1, 0.2, or 0.3 mg/kg/d naloxone (ephedrine + low,moderate and high doses of naloxone groups), and with 0.5 mL saline (model group), respectively.MAIN OUTCOME MEASURES: GAP-43, synaptophysin and β -endorphin expression were detected in the hippocampal CA3 area using immunohistochemistry 1-4 weeks after surgery. Sensorimotor integration in rats was assessed using the beam walking test.RESULTS: GAP-43 and synaptophysin expression was greater in the ephedrine group, and in the ephedrine + moderate and high doses of naloxone groups

  20. Optimizing dose enhancement with Ta2O5 nanoparticles for synchrotron microbeam activated radiation therapy.

    Science.gov (United States)

    Engels, Elette; Corde, Stéphanie; McKinnon, Sally; Incerti, Sébastien; Konstantinov, Konstantin; Rosenfeld, Anatoly; Tehei, Moeava; Lerch, Michael; Guatelli, Susanna

    2016-12-01

    Microbeam Radiation Therapy (MRT) exploits tumour selectivity and normal tissue sparing with spatially fractionated kilovoltage X-ray microbeams through the dose volume effect. Experimental measurements with Ta2O5 nanoparticles (NPs) in 9L gliosarcoma treated with MRT at the Australian Synchrotron, increased the treatment efficiency. Ta2O5 NPs were observed to form shells around cell nuclei which may be the reason for their efficiency in MRT. In this article, our experimental observation of NP shell formation is the basis of a Geant4 radiation transport study to characterise dose enhancement by Ta2O5 NPs in MRT. Our study showed that NP shells enhance the physical dose depending microbeam energy and their location relative to a single microbeam. For monochromatic microbeam energies below ∼70keV, NP shells show highly localised dose enhancement due to the short range of associated secondary electrons. Low microbeam energies indicate better targeted treatment by allowing higher microbeam doses to be administered to tumours and better exploit the spatial fractionation related selectivity observed with MRT. For microbeam energies above ∼100keV, NP shells extend the physical dose enhancement due to longer-range secondary electrons. Again, with NPs selectively internalised, the local effectiveness of MRT is expected to increase in the tumour. Dose enhancement produced by the shell aggregate varied more significantly in the cell population, depending on its location, when compared to a homogeneous NP distribution. These combined simulation and experimental data provide first evidence for optimising MRT through the incorporation of newly observed Ta2O5 NP distributions within 9L cancer cells. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  1. Biomechanical analysis of reducing sacroiliac joint shear load by optimization of pelvic muscle and ligament forces

    NARCIS (Netherlands)

    J.J.M. Pel (Johan); C.W. Spoor (Cornelis); A.L. Pool-Goudzwaard (Annelies); G.A. Hoek van Dijke; C.J. Snijders (Chris)

    2008-01-01

    textabstractEffective stabilization of the sacroiliac joints (SIJ) is essential, since spinal loading is transferred via the SIJ to the coxal bones, and further to the legs. We performed a biomechanical analysis of SIJ stability in terms of reduced SIJ shear force in standing posture using a validat

  2. Preparation, characterization, and optimization of primaquine-loaded solid lipid nanoparticles

    CSIR Research Space (South Africa)

    Omwoyo, WN

    2014-08-01

    Full Text Available . The aim of this work was to design, synthesize, and characterize PQ-loaded solid lipid nanoparticles (SLNs) (PQ-SLNs) as a potential drug-delivery system. SLNs were prepared by a modified solvent emulsification evaporation method based on a water...

  3. New impact specimen for adhesives: optimization of high-speed-loaded adhesive joints

    NARCIS (Netherlands)

    Bezemer, A.A.; Guyt, C.B.; Vlot, A.

    1998-01-01

    A new kind of joint specimen has been developed to load the adhesive in pure shear on impact. The specimen is tested with three adhesives at five layer thicknesses, and at three test speeds. From these tests it can be concluded that the rod-ring specimen is suitable for use in impact tests at high s

  4. Human and technical factors in the doses reduction and optimization at Cogema/Marcoule; Facteurs techniques et humains dans la reduction et l'optimisation des doses a Cogema/Marcoule

    Energy Technology Data Exchange (ETDEWEB)

    Bourgogne, J.L. [Cogema, 30 - Marcoule (France)

    1998-07-01

    In the case of Cogema/Marcoule, the constant decrease of radiation doses is attributed to three factors: technical with a surveillance system and doses optimization, relational with the promotion of confidence in teams of radiation protection services as an acceptation factor of radiation protection techniques and psychological with an evolution of minds towards the ALARA approach. (N.C.)

  5. Scale up, optimization and stability analysis of Curcumin C3 complex-loaded nanoparticles for cancer therapy

    Directory of Open Access Journals (Sweden)

    Ranjan Amalendu P

    2012-08-01

    Full Text Available Abstract Background Nanoparticle based delivery of anticancer drugs have been widely investigated. However, a very important process for Research & Development in any pharmaceutical industry is scaling nanoparticle formulation techniques so as to produce large batches for preclinical and clinical trials. This process is not only critical but also difficult as it involves various formulation parameters to be modulated all in the same process. Methods In our present study, we formulated curcumin loaded poly (lactic acid-co-glycolic acid nanoparticles (PLGA-CURC. This improved the bioavailability of curcumin, a potent natural anticancer drug, making it suitable for cancer therapy. Post formulation, we optimized our process by Reponse Surface Methodology (RSM using Central Composite Design (CCD and scaled up the formulation process in four stages with final scale-up process yielding 5 g of curcumin loaded nanoparticles within the laboratory setup. The nanoparticles formed after scale-up process were characterized for particle size, drug loading and encapsulation efficiency, surface morphology, in vitro release kinetics and pharmacokinetics. Stability analysis and gamma sterilization were also carried out. Results Results revealed that that process scale-up is being mastered for elaboration to 5 g level. The mean nanoparticle size of the scaled up batch was found to be 158.5 ± 9.8 nm and the drug loading was determined to be 10.32 ± 1.4%. The in vitro release study illustrated a slow sustained release corresponding to 75% drug over a period of 10 days. The pharmacokinetic profile of PLGA-CURC in rats following i.v. administration showed two compartmental model with the area under the curve (AUC0-∞ being 6.139 mg/L h. Gamma sterilization showed no significant change in the particle size or drug loading of the nanoparticles. Stability analysis revealed long term physiochemical stability of the PLGA-CURC formulation. Conclusions A successful

  6. Investigation of optimal beam margins for stereotactic radiotherapy of lung-cancer using Monte Carlo dose calculations

    Energy Technology Data Exchange (ETDEWEB)

    Jin, L; Wang, L; Li, J; Luo, W; Feigenberg, S J; Ma, C-M [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA 19111 (United States)

    2007-07-21

    This work investigated the selection of beam margins in lung-cancer stereotactic body radiotherapy (SBRT) with 6 MV photon beams. Monte Carlo dose calculations were used to systematically and quantitatively study the dosimetric effects of beam margins for different lung densities (0.1, 0.15, 0.25, 0.35 and 0.5 g cm{sup -3}), planning target volumes (PTVs) (14.4, 22.1 and 55.3 cm{sup 3}) and numbers of beam angles (three, six and seven) in lung-cancer SBRT in order to search for optimal beam margins for various clinical situations. First, a large number of treatment plans were generated in a commercial treatment planning system, and then recalculated using Monte Carlo simulations. All the plans were normalized to ensure that 95% of the PTV at least receives the prescription dose and compared quantitatively. Based on these plans, the relationships between the beam margin and quantities such as the lung toxicity (quantified by V{sub 20}, the percentage volume of the two lungs receiving at least 20 Gy) and the maximum target (PTV) dose were established for different PTVs and lung densities. The impact of the number of beam angles on the relationship between V{sub 20} and the beam margin was assessed. Quantitative information about optimal beam margins for lung-cancer SBRT was obtained for clinical applications.

  7. Deterministic optimization methods for designing high-loaded turbo-engines; Einsatz deterministischer Optimierungsverfahren bei der Vorauslegung hochbelasteter Turbomaschinen

    Energy Technology Data Exchange (ETDEWEB)

    Spiegel, M.S.

    2000-07-01

    Deterministic optimisation methods are valuable tools for multiparameter design of high-loaded turbo-engines as they can identify potentials for improvement and new approaches for optimization of turbo-engine configurations, provided that the assessment functions and methods of design meet the requirements of the optimization processes. Two examples are presented, a high-deflection transsonic tandem guide grid and a strongly cooled high-performance turbine. [German] Mit dem Einsatz deterministischer Optimierungsverfahren als Hilfsmittel bei der vielparametrischen Vorauslegung hochbelasteter Turbomaschinen besteht die Moeglichkeit, mit hoeherer Effizienz Verbesserungspotentiale und neue Ansaetze fuer optimale Turbomaschinen-Konfigurationen aufzuzeigen. Voraussetzung ist, dass die angesetzten Bewertungsfunktionen und die verwendeten Auslegungsverfahren den Anforderungen der Optimierungsverfahren entsprechen. Anhand zweler Optimierungsbeispiele (hochumlenkendes transsonisches Tandemleitgitter und stark gekuehlte Hochleistungsturbine) werden fuer die Optimierung mit einem SQP-Verfahren in Verbindung mit einer uebergeordneten Intervallteilungsstrategie die Formulierung der Aufgabenstellung sowie die Vorgehensweisen bei der thermogasdynamischen Auslegungsberechnung erlaeutert und die Ergebnisse der Optimierungen praesentiert. (orig.)

  8. Optimization Design of Structures Subjected to Transient Loads Using First and Second Derivatives of Dynamic Displacement and Stress

    Directory of Open Access Journals (Sweden)

    Qimao Liu

    2012-01-01

    Full Text Available This paper developed an effective optimization method, i.e., gradient-Hessian matrix-based method or second order method, of frame structures subjected to the transient loads. An algorithm of first and second derivatives of dynamic displacement and stress with respect to design variables is formulated based on the Newmark method. The inequality time-dependent constraint problem is converted into a sequence of appropriately formed time-independent unconstrained problems using the integral interior point penalty function method. The gradient and Hessian matrixes of the integral interior point penalty functions are also computed. Then the Marquardt's method is employed to solve unconstrained problems. The numerical results show that the optimal design method proposed in this paper can obtain the local optimum design of frame structures and sometimes is more efficient than the augmented Lagrange multiplier method.

  9. Optimization of the fractionated irradiation scheme considering physical doses to tumor and organ at risk based on dose–volume histograms

    Energy Technology Data Exchange (ETDEWEB)

    Sugano, Yasutaka [Graduate School of Health Sciences, Hokkaido University, Kita-12, Nishi-5, Kita-ku, Sapporo, Hokkaido 060-0812 (Japan); Mizuta, Masahiro [Laboratory of Advanced Data Science, Information Initiative Center, Hokkaido University, Kita-11, Nishi-5, Kita-ku, Sapporo, Hokkaido 060-0811 (Japan); Takao, Seishin; Shirato, Hiroki; Sutherland, Kenneth L. [Department of Radiation Medicine, Graduate School of Medicine, Hokkaido University, Kita-15, Nishi-5, Kita-ku, Sapporo, Hokkaido 060-8638 (Japan); Date, Hiroyuki, E-mail: date@hs.hokudai.ac.jp [Faculty of Health Sciences, Hokkaido University, Kita-12, Nishi-5, Kita-ku, Sapporo, Hokkaido 060-0812 (Japan)

    2015-11-15

    Purpose: Radiotherapy of solid tumors has been performed with various fractionation regimens such as multi- and hypofractionations. However, the ability to optimize the fractionation regimen considering the physical dose distribution remains insufficient. This study aims to optimize the fractionation regimen, in which the authors propose a graphical method for selecting the optimal number of fractions (n) and dose per fraction (d) based on dose–volume histograms for tumor and normal tissues of organs around the tumor. Methods: Modified linear-quadratic models were employed to estimate the radiation effects on the tumor and an organ at risk (OAR), where the repopulation of the tumor cells and the linearity of the dose-response curve in the high dose range of the surviving fraction were considered. The minimization problem for the damage effect on the OAR was solved under the constraint that the radiation effect on the tumor is fixed by a graphical method. Here, the damage effect on the OAR was estimated based on the dose–volume histogram. Results: It was found that the optimization of fractionation scheme incorporating the dose–volume histogram is possible by employing appropriate cell surviving models. The graphical method considering the repopulation of tumor cells and a rectilinear response in the high dose range enables them to derive the optimal number of fractions and dose per fraction. For example, in the treatment of prostate cancer, the optimal fractionation was suggested to lie in the range of 8–32 fractions with a daily dose of 2.2–6.3 Gy. Conclusions: It is possible to optimize the number of fractions and dose per fraction based on the physical dose distribution (i.e., dose–volume histogram) by the graphical method considering the effects on tumor and OARs around the tumor. This method may stipulate a new guideline to optimize the fractionation regimen for physics-guided fractionation.

  10. Is dosing of therapeutic immunoglobulins optimal? – A review of a 3-decade long debate in Europe.

    Directory of Open Access Journals (Sweden)

    Jacqueline eKerr

    2014-12-01

    Full Text Available The consumption of immunoglobulins (Ig is increasing due to better recognition of antibody deficiencies, an aging population and new indications. This review aims to examine the various dosing regimens and research developments in the established and in some of the relevant off-label indications in Europe. The background to the current regulatory settings in Europe is provided as a backdrop for the latest developments in primary and secondary immunodeficiencies and in immunomodulatory indications. In these heterogeneous areas, clinical trials encompassing different routes of administration, varying intervals and infusion rates are paving the way towards more individualized therapy regimens.In primary antibody deficiencies adjustments in dosing and intervals will depend on the clinical presentation, effective IgG trough levels and IgG metabolism. Ideally, individual pharmacokinetic profiles in conjunction with the clinical phenotype could lead to highly tailored treatment. In practice, incremental dosage increases are necessary to titrate the optimal dose for more severely ill patients. Higher intravenous doses in these patients also have beneficial immunomodulatory effects beyond mere IgG replacement. Better understanding of the pharmacokinetics of Ig therapy is leading to a move away from simplistic ‘per kg’ dosing.Defective antibody production is common in many secondary immunodeficiencies irrespective of whether the causative factor was lymphoid malignancies (established indications, certain autoimmune disorders, immunosuppressive agents or biologics. This antibody failure, as shown by test immunisation, may be amenable to treatment with replacement Ig therapy. In certain immunomodulatory settings (e.g. ITP selection of patients for Ig therapy may be enhanced by relevant biomarkers in order to exclude non-responders and thus obtain higher response rates. In this review the developments in dosing of therapeutic immunoglobulins have been

  11. The optimal exhaled concentration of sevoflurane for intubation without neuromuscular blockade using clinical bolus doses of remifentanil

    Science.gov (United States)

    Goo, Eui-Kyoung; Lee, Jong Seok; Koh, Jae Chul

    2017-01-01

    Abstract Background: The aim of this study was to investigate the optimal exhaled sevoflurane concentration that produces adequate endotracheal intubation conditions when sevoflurane is combined with the different bolus doses of remifentanil used in clinical practice. Methods: The patients were randomized to 3 groups (groups 1.0, 1.5, and 2.0), receiving remifentanil bolus doses of 1.0, 1.5, and 2.0 μg/kg, respectively. For each group, the concentration of sevoflurane used for each consecutive patient was increased or decreased using the “up-and-down” method based on the success or failure to achieve adequate conditions for intubation in the previous patient. The remifentanil bolus dose was administered 90 s before intubation and after the target sevoflurane concentration was achieved. Results: In groups 1.0, 1.5, and 2.0, the effective concentration in 50% (EC50) of the sevoflurane concentration required to perform successful intubation was 3.0, 2.0, and 1.29 vol% and the effective concentration in 95% was 3.45, 2.91, and 1.89 vol%, respectively. When sevoflurane was administered for the induction, the increase in heart rate (HR) of group 1.0 was the highest among the groups. The highest number of adverse events occurred in group 2.0, including vocal cord rigidity, hypotension, and bradycardia. Discussion: The EC50 of the sevoflurane concentration was 3.0, 2.0, and 1.29 vol% when it was combined with a bolus dose of remifentanil of 1.0, 1.5, and 2.0 μg/kg, respectively. Of the 3 different bolus doses of remifentanil, the dose of 1.5 μg/kg was least associated with changes in the HR/mean blood pressure during intubation without increasing adverse effects. PMID:28248887

  12. SU-E-T-456: Impact of Dose Calculation Algorithms On Biologically Optimized VMAT Plans for Esophageal Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Thiyagarajan, Rajesh; Vikraman, S; Karrthick, KP; Ramu, M; Sambasivaselli, R; Senniandavar, V; Kataria, Tejinder [Medanta The Medicity, Gurgaon, Haryana (India); Nambiraj, N Arunai; Sigamani, Ashokkumar [VIT University, Vellore, Tamil Nadu (India); Subbarao, Bargavan [Elekta India, Chennai, Tamil Nadu (India)

    2015-06-15

    Purpose: To evaluate the impact of dose calculation algorithm on the dose distribution of biologically optimized Volumatric Modulated Arc Therapy (VMAT) plans for Esophgeal cancer. Methods: Eighteen retrospectively treated patients with carcinoma esophagus were studied. VMAT plans were optimized using biological objectives in Monaco (5.0) TPS for 6MV photon beam (Elekta Infinity). These plans were calculated for final dose using Monte Carlo (MC), Collapsed Cone Convolution (CCC) & Pencil Beam Convolution (PBC) algorithms from Monaco and Oncentra Masterplan TPS. A dose grid of 2mm was used for all algorithms and 1% per plan uncertainty maintained for MC calculation. MC based calculations were considered as the reference for CCC & PBC. Dose volume histogram (DVH) indices (D95, D98, D50 etc) of Target (PTV) and critical structures were compared to study the impact of all three algorithms. Results: Beam models were consistent with measured data. The mean difference observed in reference with MC calculation for D98, D95, D50 & D2 of PTV were 0.37%, −0.21%, 1.51% & 1.18% respectively for CCC and 3.28%, 2.75%, 3.61% & 3.08% for PBC. Heart D25 mean difference was 4.94% & 11.21% for CCC and PBC respectively. Lung Dmean mean difference was 1.5% (CCC) and 4.1% (PBC). Spinal cord D2 mean difference was 2.35% (CCC) and 3.98% (PBC). Similar differences were observed for liver and kidneys. The overall mean difference found for target and critical structures was 0.71±1.52%, 2.71±3.10% for CCC and 3.18±1.55%, 6.61±5.1% for PBC respectively. Conclusion: We observed a significant overestimate of dose distribution by CCC and PBC as compared to MC. The dose prediction of CCC is closer (<3%) to MC than that of PBC. This can be attributed to poor performance of CCC and PBC in inhomogeneous regions around esophagus. CCC can be considered as an alternate in the absence of MC algorithm.

  13. SU-E-J-113: The Influence of Optimizing Pediatric CT Simulator Protocols On the Treatment Dose Calculation in Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y; Zhang, J; Hu, Q; Tie, J; Wu, H [Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Radiotherapy, Peking University Cancer Hospital ' Institute, Beijing (China); Deng, J [Department of Therapeutic Radiology, Yale University, New Haven, CT (United States)

    2014-06-01

    Purpose: To investigate the possibility of applying optimized scanning protocols for pediatric CT simulation by quantifying the dosimetric inaccuracy introduced by using a fixed HU to density conversion. Methods: The images of a CIRS electron density reference phantom (Model 062) were acquired by a Siemens CT simulator (Sensation Open) using the following settings of tube voltage and beam current: 120 kV/190mA (the reference protocol used to calibrate CT for our treatment planning system (TPS)); Fixed 190mA combined with all available kV: 80, 100, and 140; fixed 120 kV and various current from 37 to 444 mA (scanner extremes) with interval of 30 mA. To avoid the HU uncertainty of point sampling in the various inserts of known electron densities, the mean CT numbers of the central cylindrical volume were calculated using DICOMan software. The doses per 100 MU to the reference point (SAD=100cm, Depth=10cm, Field=10X10cm, 6MV photon beam) in a virtual cubic phantom (30X30X30cm) were calculated using Eclipse TPS (calculation model: AcurosXB-11031) by assigning the CT numbers to HU of typical materials acquired by various protocols. Results: For the inserts of densities less than muscle, CT number fluctuations of all protocols were within the tolerance of 10 HU as accepted by AAPM-TG66. For more condensed materials, fixed kV yielded stable HU with any mA combination where largest disparities were found in 1750mg/cc insert: HU{sub reference}=1801(106.6cGy), HU{sub minimum}=1799 (106.6cGy, error{sub dose}=0.00%), HU{sub maximum}=1815 (106.8cGy, error{sub dose}=0.19%). Yet greater disagreements were observed with increasing density when kV was modified: HU{sub minimum}=1646 (104.5cGy, error{sub dose}=- 1.97%), HU{sub maximum}=2487 (116.4cGy, error{sub dose}=9.19%) in 1750mg/cc insert. Conclusion: Without affecting treatment dose calculation, personalized mA optimization of CT simulator can be conducted by fixing kV for a better cost-effectiveness of imaging dose and quality

  14. Poly ɛ-caprolactone nanoparticles loaded with Uncaria tomentosa extract: preparation, characterization, and optimization using the Box–Behnken design

    Science.gov (United States)

    Ribeiro, Ana Ferreira; de Oliveira Rezende, Ricardo Leite; Cabral, Lúcio Mendes; de Sousa, Valéria Pereira

    2013-01-01

    Purpose The aim of this research was to develop and optimize a process for obtaining poly ɛ-caprolactone (PCL) nanoparticles loaded with Uncaria tomentosa (UT) extract. Methods Nanoparticles were produced by the oil-in-water emulsion solvent evaporation method. Preliminary experiments determined the initial conditions of the organic phase (OP) and of the aqueous phase (AP) that would be utilized for this study. Ultimately, a three-factor three-level Box–Behnken design (BBD) was employed during the optimization process. PCL and polyvinyl alcohol (PVA) concentrations (X1 and X2, respectively) and the AP/OP volume ratio (X3) were the independent variables studied, while entrapment efficiency (Y1), particle mean diameter (Y2), polydispersity (Y3), and zeta potential (Y4) served as the evaluated responses. Results Preliminary experiments revealed that the optimal initial conditions for the preparation of nanoparticles were as follows: OP composed of 5 mL ethyl acetate/acetone (3/2) mixture containing UT extract and PCL, and an AP of buffered PVA (pH 7.5) solution. Statistical analysis of the BBD results indicated that all of the studied factors had significant effects on the responses Y1, Y2, and Y4, and these effects are closely described or fitted by regression equations. Based on the obtained models and the selected desirability function, the nanoparticles were optimized to maximize Y1 and minimize Y2. These optimal conditions were achieved using 3% (w/v) PCL, 1% (w/v) PVA, and an AP/OP ratio of 1.7, with predicted values of 89.1% for Y1 and 280 nm for Y2. Another batch was produced under the same optimal conditions. The entrapment efficiency of this new batch was measured at 81.6% (Y1) and the particles had a mean size of 247 nm (Y2) and a polydispersity index of 0.062 (Y3). Conclusion This investigation obtained UT-loaded nanoparticle formulations with desired characteristics. The BBD approach was a useful tool for nanoparticle development and optimization, and

  15. Poly ɛ-caprolactone nanoparticles loaded with Uncaria tomentosa extract: preparation, characterization, and optimization using the Box-Behnken design.

    Science.gov (United States)

    Ribeiro, Ana Ferreira; de Oliveira Rezende, Ricardo Leite; Cabral, Lúcio Mendes; de Sousa, Valéria Pereira

    2013-01-01

    The aim of this research was to develop and optimize a process for obtaining poly ɛ-caprolactone (PCL) nanoparticles loaded with Uncaria tomentosa (UT) extract. Nanoparticles were produced by the oil-in-water emulsion solvent evaporation method. Preliminary experiments determined the initial conditions of the organic phase (OP) and of the aqueous phase (AP) that would be utilized for this study. Ultimately, a three-factor three-level Box-Behnken design (BBD) was employed during the optimization process. PCL and polyvinyl alcohol (PVA) concentrations (X(1) and X(2), respectively) and the AP/OP volume ratio (X(3)) were the independent variables studied, while entrapment efficiency (Y(1)), particle mean diameter (Y(2)), polydispersity (Y(3)), and zeta potential (Y(4)) served as the evaluated responses. PRELIMINARY EXPERIMENTS REVEALED THAT THE OPTIMAL INITIAL CONDITIONS FOR THE PREPARATION OF NANOPARTICLES WERE AS FOLLOWS: OP composed of 5 mL ethyl acetate/acetone (3/2) mixture containing UT extract and PCL, and an AP of buffered PVA (pH 7.5) solution. Statistical analysis of the BBD results indicated that all of the studied factors had significant effects on the responses Y(1), Y(2), and Y(4,) and these effects are closely described or fitted by regression equations. Based on the obtained models and the selected desirability function, the nanoparticles were optimized to maximize Y(1) and minimize Y(2). These optimal conditions were achieved using 3% (w/v) PCL, 1% (w/v) PVA, and an AP/OP ratio of 1.7, with predicted values of 89.1% for Y(1) and 280 nm for Y(2). Another batch was produced under the same optimal conditions. The entrapment efficiency of this new batch was measured at 81.6% (Y(1)) and the particles had a mean size of 247 nm (Y(2)) and a polydispersity index of 0.062 (Y(3)). This investigation obtained UT-loaded nanoparticle formulations with desired characteristics. The BBD approach was a useful tool for nanoparticle development and optimization, and

  16. Poly ε-caprolactone nanoparticles loaded with Uncaria tomentosa extract: preparation, characterization, and optimization using the Box–Behnken design

    Directory of Open Access Journals (Sweden)

    Ribero AF

    2013-01-01

    Full Text Available Ana Ferreira Ribeiro, Ricardo Leite de Oliveira Rezende, Lúcio Mendes Cabral, Valéria Pereira de SousaDepartment of Pharmaceutics, Faculty of Pharmacy, Federal University of Rio de Janeiro, Rio de Janeiro, BrazilPurpose: The aim of this research was to develop and optimize a process for obtaining poly ε-caprolactone (PCL nanoparticles loaded with Uncaria tomentosa (UT extract.Methods: Nanoparticles were produced by the oil-in-water emulsion solvent evaporation method. Preliminary experiments determined the initial conditions of the organic phase (OP and of the aqueous phase (AP that would be utilized for this study. Ultimately, a three-factor three-level Box–Behnken design (BBD was employed during the optimization process. PCL and polyvinyl alcohol (PVA concentrations (X1 and X2, respectively and the AP/OP volume ratio (X3 were the independent variables studied, while entrapment efficiency (Y1, particle mean diameter (Y2, polydispersity (Y3, and zeta potential (Y4 served as the evaluated responses.Results: Preliminary experiments revealed that the optimal initial conditions for the preparation of nanoparticles were as follows: OP composed of 5 mL ethyl acetate/acetone (3/2 mixture containing UT extract and PCL, and an AP of buffered PVA (pH 7.5 solution. Statistical analysis of the BBD results indicated that all of the studied factors had significant effects on the responses Y1, Y2, and Y4, and these effects are closely described or fitted by regression equations. Based on the obtained models and the selected desirability function, the nanoparticles were optimized to maximize Y1 and minimize Y2. These optimal conditions were achieved using 3% (w/v PCL, 1% (w/v PVA, and an AP/OP ratio of 1.7, with predicted values of 89.1% for Y1 and 280 nm for Y2. Another batch was produced under the same optimal conditions. The entrapment efficiency of this new batch was measured at 81.6% (Y1 and the particles had a mean size of 247 nm (Y2 and a

  17. Optimization of the therapeutic dose of {sup 131}I for thyroid differentiated carcinoma; Otimizacao da dose terapeutica com {sup 131}I para carcinoma diferenciado da tiroide

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Fabiana Farias de

    2002-09-01

    reduction for many organs, such as the narrow and gonads, of up to 78.4%.Possible benefits to the institution also include the use of less radioactive material and a reduction in radiation exposures to the staff during the manipulation and administration of the {sup 131} I. To facilitate the calculations of the optimum therapeutic activity of {sup 131} I for individual patients, a simple and fast dose planning program was created (PlanDose). The program has been set up to evaluate thryroid remant ablation, but it can also be used for the calculation of the activity to be administered for treatment of hyperthyroidism. This protocol of calculated optimal patient-specific {sup 131} I. activities allows a better determination of the necessary ablative dose for patients with differentiated carcinoma of the thyroid, and is an example of optimizing the practice of radiation protection. (author)

  18. Optimized dose regimen for whole-body FDG-PET imaging

    NARCIS (Netherlands)

    de Groot, Eleonore H.; Post, Nieky; Boellaard, Ronald; Wagenaar, Nils R. L.; Willemsen, Antoon T. M.; van Dalen, Jorn A.

    2013-01-01

    Background: The European Association of Nuclear Medicine procedure guidelines for whole-body fluorodeoxyglucose positron-emission tomography (FDG-PET) scanning prescribe a dose proportional to the patient's body mass. However, clinical practice shows degraded image quality in obese patients

  19. Determination of an optimal dose of medetomidine-ketamine-buprenorphine for anaesthesia in the Cape ground squirrel (Xerus inauris

    Directory of Open Access Journals (Sweden)

    K. E. Joubert

    2011-04-01

    Full Text Available The optimal dose of medetomidine-ketamine-buprenorphine was determined in 25 Cape ground squirrels (Xerus inauris undergoing surgical implantation of a temperature logger into the abdominal cavity. At the end of anaesthesia, the squirrels were given atipamezole intramuscularly to reverse the effects of medetomidine. The mean dose of medetomidine was 67.6±9.2 μg/kg, ketamine 13.6±1.9 mg/kg and buprenorphine 0.5±0.06 μg/kg. Induction time was 3.1 ± 1.4 min. This produced surgical anaesthesia for 21± 4.2 min. Atipamezole 232±92 μg/kg produced a rapid recovery. Squirrels were sternally recumbent in 3.5 ± 2.2 min.

  20. The pendular mechanism does not determine the optimal speed of loaded walking on gradients.

    Science.gov (United States)

    Gomeñuka, Natalia Andrea; Bona, Renata Luisa; da Rosa, Rodrigo Gomes; Peyré-Tartaruga, Leonardo Alexandre

    2016-06-01

    The pendular mechanism does not act as a primary mechanism in uphill walking due to the monotonic behavior of the mechanical energies of the center of mass. Nevertheless, recent evidence shows that there is an important minimization of energy expenditure by the pendular mechanism during walking on uphill gradients. In this study, we analyzed the optimum speed (OPT) of loaded human walking and the pendulum-like determining variables (Recovery R, Instantaneous pendular re-conversion Rint, and Congruity percentage %Cong). Ten young men walked on a treadmill at five different speeds and at three different treadmill incline gradients (0, +7 and +15%), with and without a load carried in their backpacks. We used indirect calorimetry and 3D motion analysis, and all of the data were analyzed by computational algorithms. Rint increased at higher speeds and decreased with increasing gradient. R and %Cong decreased with increasing gradient and increased with speed, independent of load. Thus, energy conversion by the pendular mechanism during walking on a 15% gradient is supported, and although this mechanism can explain the maintenance of OPT at low walking speeds, the pendular mechanism does not fully explain the energy minimization at higher speeds.

  1. Optimization of hybrid power system composed of SMES and flywheel MG for large pulsed load

    Science.gov (United States)

    Niiyama, K.; Yagai, T.; Tsuda, M.; Hamajima, T.

    2008-09-01

    A superconducting magnetic storage system (SMES) has some advantages such as rapid large power response and high storage efficiency which are superior to other energy storage systems. A flywheel motor generator (FWMG) has large scaled capacity and high reliability, and hence is broadly utilized for a large pulsed load, while it has comparatively low storage efficiency due to high mechanical loss compared with SMES. A fusion power plant such as International Thermo-Nuclear Experimental Reactor (ITER) requires a large and long pulsed load which causes a frequency deviation in a utility power system. In order to keep the frequency within an allowable deviation, we propose a hybrid power system for the pulsed load, which equips the SMES and the FWMG with the utility power system. We evaluate installation cost and frequency control performance of three power systems combined with energy storage devices; (i) SMES with the utility power, (ii) FWMG with the utility power, (iii) both SMES and FWMG with the utility power. The first power system has excellent frequency power control performance but its installation cost is high. The second system has inferior frequency control performance but its installation cost is the lowest. The third system has good frequency control performance and its installation cost is attained lower than the first power system by adjusting the ratio between SMES and FWMG.

  2. Achieving consistent image quality with dose optimization in 64-row multidetector computed tomography prospective ECG gated coronary calcium scoring.

    Science.gov (United States)

    Pan, Zilai; Pang, Lifang; Li, Jianying; Zhang, Huan; Yang, Wenjie; Ding, Bei; Chai, Weimin; Chen, Kemin; Yao, Weiwu

    2011-04-01

    To evaluate the clinical value of a body mass index (BMI) based tube current (mA) selection method for obtaining consistent image quality with dose optimization in MDCT prospective ECG gated coronary calcium scoring. A formula for selecting mA to achieve desired image quality based on patient BMI was established using a control group (A) of 200 MDCT cardiac patients with a standard scan protocol. One hundred patients in Group B were scanned with this BMI-dependent mA for achieving a desired noise level of 18 HU at 2.5 mm slice thickness. The CTDIvol and image noise on the ascending aorta for the two groups were recorded. Two experienced radiologists quantitatively evaluated the image quality using scores of 1-4 with 4 being the highest. The image quality scores had no statistical difference (P = 0.71) at 3.89 ± 0.32, 3.87 ± 0.34, respectively, for groups A and B of similar BMI. The image noise in Group A had linear relationship with BMI. The image noise in Group B using BMI-dependent mA was independent of BMI with average value of 17.9 HU and smaller deviations for the noise values than in Group A (2.0 vs. 2.9 HU). There was a 35% dose reduction with BMI-dependent mA selection method on average with the lowest effective dose being only 0.35 mSv for patient with BMI of 18.3. A quantitative BMI-based mA selection method in MDCT prospective ECG gated coronary calcium scoring has been proposed to obtain a desired and consistent image quality and provide dose optimization across patient population.

  3. Optimization of Ru{sub x}Se{sub y} electrocatalyst loading for oxygen reduction in a PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Huerta, R.G. [Instituto Politecnico Nacional, Laboratorio de Electroquimica y Corrosion ESIQIE, UPALP, 07738 Mexico, D.F., Mexico (Mexico); Guzman-Guzman, A.; Solorza-Feria, O. [Depto. Quimica, Centro de Investigacion y de Estudios Avanzados del IPN, A. Postal 14-740, 07360 Mexico D.F., Mexico (Mexico)

    2010-11-15

    The synthesis, characterization and optimization of Ru{sub x}Se{sub y} catalyst loading as a cathode electrode for a single polymer electrolyte membrane fuel cell, PEMFC were investigated. Ru{sub x}Se{sub y} catalyst was synthesized via a decarbonylation of Ru{sub 3}(CO){sub 12} and elemental selenium in 1,6-hexanediol under refluxing conditions for 2 h. The powder electrocatalyst was characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), and examined for the oxygen reduction reaction (ORR) in 0.5M H{sub 2}SO{sub 4} by rotating disk electrode (RDE) and in membrane-electrode assemblies, MEAs for a single PEMFC. Results indicate the formation of agglomerates of crystalline particles with nanometric size embedded in an amorphous phase. The catalyst exhibited high current density and lower overpotential for the ORR compared to that of Ru{sub x} cluster catalyst. Dispersed Ru{sub x}Se{sub y} catalyst loading on Vulcan carbon was optimized as a cathode electrode by performance testing in a single H{sub 2}-O{sub 2} fuel cell. (author)

  4. Factorial design based preparation, optimization, characterization and in vitro drug release studies of olanzapine loaded PLGA nanoparticles

    Science.gov (United States)

    Bohrey, Sarvesh; Chourasiya, Vibha; Pandey, Archna

    2016-12-01

    The objective of the present work was to develop and optimize olanzapine loaded polymeric nanoparticles using a factorial design. The presented work developed and optimized olanzapine loaded polymeric nanoparticles by using a 33 factorial design. The 33 factorial design was used for studying the effect of the main preparation variables on particle size and percent drug entrapment efficiency of the nanoparticles. A modified nanoprecipitation method was used to prepare nanoparticles successfully by using the biodegradable polymer poly(lactic-co-glycolic)acid (PLGA), and they were characterized for various parameters such as particle size, shape, zeta potential, percent drug entrapment efficiency, percent process yield and in vitro drug release behavior. Examination of the interaction between the excipients used as well as investigation of the nature of the drug, the formulation and the nature of the drug in the formulations was carried out by FTIR studies. Different kinetic models were used to analyze the in vitro drug release data. The preferred formulation showed a particle size of 127.6 ± 1.9 nm, PDI of 0.239 ± 0.013, zeta potential of -29.2 mV, entrapment efficiency of 72.46 ± 3.8% and process yield of 89.65 ± 1.3%. TEM results showed that these nanoparticles were spherical in shape and follow the Korsmeyer-Peppas model with different release exponent values.

  5. Optimizing loading path and die linetype of large length-to-diameter ratio metal stator screw lining hydroforming

    Institute of Scientific and Technical Information of China (English)

    祝效华; 石昌帅; 童华

    2015-01-01

    In order to meet the high temperature environment requirement of deep and superdeep well exploitation, a technology of large length-to-diameter ratio metal stator screw lining meshing with rotor is presented. Based on the elastic-plasticity theory, and under the consideration of the effect of tube size, material mechanical parameters, friction coefficient and loading paths, the external pressure plastic forming mechanical model of metal stator screw lining is established, to study the optimal loading path of metal stator lining tube hydroforming process. The results show that wall thickness reduction of the external pressure tube hydroforming (THF) is about 4%, and three evaluation criteria of metal stator screw lining forming quality are presented: fillet stick mold coefficient, thickness relative error and forming quality coefficient. The smaller the three criteria are, the better the forming quality is. Each indicator has a trend of increase with the loading rate reducing, and the adjustment laws of die arc transition zone equidistance profile curve are acquired for improving tube forming quality. Hence, the research results prove the feasibility of external pressure THF used for processing high-accuracy large length-to-diameter ratio metal stator screw lining, and provide theoretical basis for designing new kind of stator structure which has better performance and longer service life.

  6. WE-AB-303-06: Combining DAO with MV + KV Optimization to Improve Skin Dose Sparing with Real-Time Fluoroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Grelewicz, Z; Wiersma, R [The University of Chicago, Chicago, IL (United States)

    2015-06-15

    Purpose: Real-time fluoroscopy may allow for improved patient positioning and tumor tracking, particularly in the treatment of lung tumors. In order to mitigate the effects of the imaging dose, previous studies have demonstrated the effect of including both imaging dose and imaging constraints into the inverse treatment planning object function. That method of combined MV+kV optimization may Result in plans with treatment beams chosen to allow for more gentle imaging beam-on times. Direct-aperture optimization (DAO) is also known to produce treatment plans with fluence maps more conducive to lower beam-on times. Therefore, in this work we demonstrate the feasibility of a combination of DAO and MV+kV optimization for further optimized real-time kV imaging. Methods: Therapeutic and imaging beams were modeled in the EGSnrc Monte Carlo environment, and applied to a patient model for a previously treated lung patient to provide dose influence matrices from DOSXYZnrc. An MV + kV IMRT DAO treatment planning system was developed to compare DAO treatment plans with and without MV+kV optimization. The objective function was optimized using simulated annealing. In order to allow for comparisons between different cases of the stochastically optimized plans, the optimization was repeated twenty times. Results: Across twenty optimizations, combined MV+kV IMRT resulted in an average of 12.8% reduction in peak skin dose. Both non-optimized and MV+kV optimized imaging beams delivered, on average, mean dose of approximately 1 cGy per fraction to the target, with peak doses to target of approximately 6 cGy per fraction. Conclusion: When using DAO, MV+kV optimization is shown to Result in improvements to plan quality in terms of skin dose, when compared to the case of MV optimization with non-optimized kV imaging. The combination of DAO and MV+kV optimization may allow for real-time imaging without excessive imaging dose. Financial support for the work has been provided in part by NIH

  7. Agent based Particle Swarm Optimization for Load Frequency Control of Distribution Grid

    DEFF Research Database (Denmark)

    Cha, Seung-Tae; Saleem, Arshad; Wu, Qiuwei;

    2012-01-01

    This paper presents a Particle Swarm Optimization (PSO) based on multi-agent controller. Real-time digital simulator (RTDS) is used for modelling the power system, while a PSO based multi-agent LFC algorithm is developed in JAVA for communicating with resource agents and determines the scenario t...

  8. Optimal resource allocation and load scheduling for a multi-commodity smart energy system

    NARCIS (Netherlands)

    Blaauwbroek, N.; Nguyen, P.H.; Shi, H.; Kamphuis, I.G.; Kling, W.L.; Konsman, M.J.

    2015-01-01

    The increasing introduction of district heating systems together with hybrid energy appliances as heat pumps and micro-combined heat and power installations, results in new opportunities for optimizing the available resources in multi-commodity smart energy systems, including electricity, heat and

  9. Optimizing flurbiprofen-loaded NLC by central composite factorial design for ocular delivery

    Science.gov (United States)

    Gonzalez-Mira, E.; Egea, M. A.; Souto, E. B.; Calpena, A. C.; García, M. L.

    2011-01-01

    The purpose of this study was to design and optimize a new topical delivery system for ocular administration of flurbiprofen (FB), based on lipid nanoparticles. These particles, called nanostructured lipid carriers (NLC), were composed of a fatty acid (stearic acid (SA)) as the solid lipid and a mixture of Miglyol® 812 and castor oil (CO) as the liquid lipids, prepared by the hot high pressure homogenization method. After selecting the critical variables influencing the physicochemical characteristics of the NLC (the liquid lipid (i.e. oil) concentration with respect to the total lipid (cOil/L (wt%)), the surfactant and the flurbiprofen concentration, on particle size, polydispersity index and encapsulation efficiency), a three-factor five-level central rotatable composite design was employed to plan and perform the experiments. Morphological examination, crystallinity and stability studies were also performed to accomplish the optimization study. The results showed that increasing cOil/L (wt%) was followed by an enhanced tendency to produce smaller particles, but the liquid to solid lipid proportion should not exceed 30 wt% due to destabilization problems. Therefore, a 70:30 ratio of SA to oil (miglyol + CO) was selected to develop an optimal NLC formulation. The smaller particles obtained when increasing surfactant concentration led to the selection of 3.2 wt% of Tween® 80 (non-ionic surfactant). The positive effect of the increase in FB concentration on the encapsulation efficiency (EE) and its total solubilization in the lipid matrix led to the selection of 0.25 wt% of FB in the formulation. The optimal NLC showed an appropriate average size for ophthalmic administration (228.3 nm) with a narrow size distribution (0.156), negatively charged surface (-33.3 mV) and high EE (~90%). The in vitro experiments proved that sustained release FB was achieved using NLC as drug carriers. Optimal NLC formulation did not show toxicity on ocular tissues.

  10. Optimizing flurbiprofen-loaded NLC by central composite factorial design for ocular delivery

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Mira, E; Egea, M A; Garcia, M L [Department of Physical Chemistry, Faculty of Pharmacy, Institute of Nanoscience and Nanotechnology, University of Barcelona, Avenida Joan XXIII s/n, E-08028 Barcelona (Spain); Souto, E B [Faculty of Health Sciences, Fernando Pessoa University, Rua Carlos da Maia, Nr. 296, Office S.1, P-4200-150 Porto (Portugal); Calpena, A C, E-mail: eligonzalezmi@ub.edu [Department of Biopharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of Barcelona, Avenida Joan XXIII s/n, E-08028 Barcelona (Spain)

    2011-01-28

    The purpose of this study was to design and optimize a new topical delivery system for ocular administration of flurbiprofen (FB), based on lipid nanoparticles. These particles, called nanostructured lipid carriers (NLC), were composed of a fatty acid (stearic acid (SA)) as the solid lipid and a mixture of Miglyol 812 and castor oil (CO) as the liquid lipids, prepared by the hot high pressure homogenization method. After selecting the critical variables influencing the physicochemical characteristics of the NLC (the liquid lipid (i.e. oil) concentration with respect to the total lipid (cOil/L (wt%)), the surfactant and the flurbiprofen concentration, on particle size, polydispersity index and encapsulation efficiency), a three-factor five-level central rotatable composite design was employed to plan and perform the experiments. Morphological examination, crystallinity and stability studies were also performed to accomplish the optimization study. The results showed that increasing cOil/L (wt%) was followed by an enhanced tendency to produce smaller particles, but the liquid to solid lipid proportion should not exceed 30 wt% due to destabilization problems. Therefore, a 70:30 ratio of SA to oil (miglyol + CO) was selected to develop an optimal NLC formulation. The smaller particles obtained when increasing surfactant concentration led to the selection of 3.2 wt% of Tween 80 (non-ionic surfactant). The positive effect of the increase in FB concentration on the encapsulation efficiency (EE) and its total solubilization in the lipid matrix led to the selection of 0.25 wt% of FB in the formulation. The optimal NLC showed an appropriate average size for ophthalmic administration (228.3 nm) with a narrow size distribution (0.156), negatively charged surface (-33.3 mV) and high EE ({approx}90%). The in vitro experiments proved that sustained release FB was achieved using NLC as drug carriers. Optimal NLC formulation did not show toxicity on ocular tissues.

  11. The use of Monte Carlo technique to optimize the dose distribution in total skin irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Poli, M.E.R. E-mail: esmeraldapoli@hotmail.com; Pereira, S.A.; Yoriyaz, H

    2001-06-01

    Cutaneous T-cell lymphoma (mycosis fungoides) is an indolent disease with a low percentage of cure. Total skin irradiation using an electron beam has become an efficient treatment of mycosis fungoides with curative intention, with success in almost 40% of the patients. In this work, we propose the use of a Monte Carlo technique to simulate the dose distribution in the patients during total skin irradiation treatments. Use was made of MCNP-4B, a well known and established code used to simulate transport of electrons, photons and neutrons through matter, especially in the area of reactor physics, and also finding increasing utility in medical physics. The goal of our work is to simulate different angles between each beam with a fixed treatment distance in order to obtain a uniform dose distribution in the patient.

  12. Radiotherapy for calcaneodynia. Results of a single center prospective randomized dose optimization trial

    Energy Technology Data Exchange (ETDEWEB)

    Ott, O.J.; Jeremias, C.; Gaipl, U.S.; Frey, B.; Schmidt, M.; Fietkau, R. [University Hospital Erlangen (Germany). Dept. of Radiation Oncology

    2013-04-15

    The aim of this work was to compare the efficacy of two different dose fractionation schedules for radiotherapy of patients with calcaneodynia. Between February 2006 and April 2010, 457 consecutive evaluable patients were recruited for this prospective randomized trial. All patients received radiotherapy using the orthovoltage technique. One radiotherapy series consisted of 6 single fractions/3 weeks. In case of insufficient remission of pain after 6 weeks a second radiation series was performed. Patients were randomly assigned to receive either single doses of 0.5 or 1.0 Gy. Endpoint was pain reduction. Pain was measured before, immediately after, and 6 weeks after radiotherapy using a visual analogue scale (VAS) and a comprehensive pain score (CPS). The overall response rate for all patients was 87 % directly after and 88 % 6 weeks after radiotherapy. The mean VAS values before, immediately after, and 6 weeks after treatment for the 0.5 and 1.0 Gy groups were 65.5 {+-} 22.1 and 64.0 {+-} 20.5 (p = 0.188), 34.8 {+-} 24.7 and 39.0 {+-} 26.3 (p = 0.122), and 25.1 {+-} 26.8 and 28.9 {+-} 26.8 (p = 0.156), respectively. The mean CPS before, immediately after, and 6 weeks after treatment was 10.1 {+-} 2.7 and 10.0 {+-} 3.0 (p = 0.783), 5.6 {+-} 3.7 and 6.0 {+-} 3.9 (p = 0.336), 4.0 {+-} 4.1 and 4.3 {+-} 3.6 (p = 0.257), respectively. No statistically significant differences between the two single dose trial arms for early (p = 0.216) and delayed response (p = 0.080) were found. Radiotherapy is an effective treatment option for the management of calcaneodynia. For radiation protection reasons, the dose for a radiotherapy series is recommended not to exceed 3-6 Gy. (orig.)

  13. Multi-load Optimal Design of Burner-inner-liner Under Performance Index Constraint by Second-Order Polynomial Taylor Series Method

    Directory of Open Access Journals (Sweden)

    Tu Gaoqiao

    2016-01-01

    Full Text Available Using maximum expansion pressure of n-decane, the aeroengine burner-inner-liner combustion pressure load is computed. Aerodynamic loads are obtained from internal gas pressure load and gas momentum. Multi-load second-order Taylor series equations are established using multi-variant polynomials and their sensitivities. Optimal designs are carried out using various performance index constraints. When 0.25 to 0.8 rectifications of different design variants are implemented, they converge under 5×10‒4 d-norm difference ratio.

  14. Evaluation of X ray radiation doses in pediatric examinations of cranial computerized tomography based on optimization studies; Avaliacao das doses de radiacao X em exames pediatricos de tomografia computadorizada de cranio com base em estudos de otimizacao

    Energy Technology Data Exchange (ETDEWEB)

    Daros, Kellen Adriana Curci

    2005-07-01

    This paper identifies the technical conditions for CT examination which offers lowest absorbed dose and to attend the manufacturer recommendations as far the spatial resolution is concerned. The paper evaluates the absorbed dose during cranial CT in up to 6 years children satisfying the technical condition recommended by the manufacturer and routine clinical conditions. The paper also established a quantitative relationship among the absorbed dose and its distribution in the cranial regions of pediatric patients up to 6 years old in a way to estimate the doses subject to optimized conditions

  15. Routes of administration and dose optimization of soluble antigen arrays in mice with experimental autoimmune encephalomyelitis.

    Science.gov (United States)

    Thati, Sharadvi; Kuehl, Christopher; Hartwell, Brittany; Sestak, Joshua; Siahaan, Teruna; Forrest, M Laird; Berkland, Cory

    2015-02-01

    Soluble antigen arrays (SAgAs) were developed for treating mice with experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis. SAgAs are composed of hyaluronan with grafted EAE antigen and LABL peptide (a ligand of ICAM-1). SAgA dose was tested by varying injection volume, SAgA concentration, and administration schedule. Routes of administration were explored to determine the efficacy of SAgAs when injected intramuscularly, subcutaneously, intraperitoneally, intravenously, or instilled into lungs. Injections proximal to the central nervous system (CNS) were compared with distal injection sites. Intravenous dosing was included to determine if SAgA efficiency results from systemic exposure. Pulmonary instillation (p.i.) was included as reports suggest T cells are licensed in the lungs before moving to the CNS. Decreasing the volume of injection or SAgA dose reduced treatment efficacy. Treating mice with a single injection on day 4, 7, and 10 also reduced efficacy compared with injecting on all three days. Surprisingly, changing the injection site did not lead to a significant difference in efficacy. Intravenous administration showed efficacy similar to other routes, suggesting SAgAs act systemically. When SAgAs were delivered via p.i., however, EAE mice failed to develop any symptoms, suggesting a unique lung mechanism to ameliorate EAE in mice.

  16. [Preparation of red mud loaded Co catalysts: optimization using response surface methodology (RSM) and activity evaluation].

    Science.gov (United States)

    Li, Hua-Nan; Xu, Bing-Bing; Qi, Fei; Sun, De-Zhi

    2013-11-01

    The removal efficiency of catalytic ozonation of bezafibrate (BZF) by red mud loaded Co catalysts (Co/RM) was used as the index value in statistical experimental designs. The most important factors influencing BZF degradation (P red mud, enhanced the catalytic activity. Moreover, the dissolved metal concentration in the solution for catalytic ozonation of BZF degradation by RM or Co/RM was determined by ICP-OES. The results showed that for both catalysts there was no leaching of catalytic active components into the solution, which could suggest that the two catalysts were safe and could have certain application prospect.

  17. Optimal dose of gemcitabine for the treatment of biliary tract or pancreatic cancer in patients with liver dysfunction.

    Science.gov (United States)

    Shibata, Takashi; Ebata, Tomoki; Fujita, Ken-ichi; Shimokata, Tomoya; Maeda, Osamu; Mitsuma, Ayako; Sasaki, Yasutsuna; Nagino, Masato; Ando, Yuichi

    2016-02-01

    A clear consensus does not exist about whether the initial dose of gemcitabine, an essential anticancer antimetabolite, should be reduced in patients with liver dysfunction. Adult patients with biliary tract or pancreatic cancer were divided into three groups according to whether they had mild, moderate, or severe liver dysfunction, evaluated on the basis of serum bilirubin and liver transaminase levels at baseline. As anticancer treatment, gemcitabine at a dose of 800 or 1000 mg/m(2) was given as an i.v. infusion once weekly for 3 weeks of a 4-week cycle. The patients were prospectively evaluated for adverse events during the first cycle, and the pharmacokinetics of gemcitabine and its inactive metabolite, difluorodeoxyuridine, were studied to determine the optimal initial dose of gemcitabine as monotherapy according to the severity of liver dysfunction. A total of 15 patients were studied. Liver dysfunction was mild in one patient, moderate in six, and severe in eight. All 15 patients had been undergoing biliary drainage for obstructive jaundice when they received gemcitabine. Grade 3 cholangitis developed in one patient with moderate liver dysfunction who received gemcitabine at the dose level of 1000 mg/m(2). No other patients had severe trea