Sample records for minimal optimization smo
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Automated parameterization of intermolecular pair potentials using global optimization techniques
NASA Astrophysics Data System (ADS)
Krämer, Andreas; Hülsmann, Marco; Köddermann, Thorsten; Reith, Dirk
2014-12-01
In this work, different global optimization techniques are assessed for the automated development of molecular force fields, as used in molecular dynamics and Monte Carlo simulations. The quest of finding suitable force field parameters is treated as a mathematical minimization problem. Intricate problem characteristics such as extremely costly and even abortive simulations, noisy simulation results, and especially multiple local minima naturally lead to the use of sophisticated global optimization algorithms. Five diverse algorithms (pure random search, recursive random search, CMA-ES, differential evolution, and taboo search) are compared to our own tailor-made solution named CoSMoS. CoSMoS is an automated workflow. It models the parameters' influence on the simulation observables to detect a globally optimal set of parameters. It is shown how and why this approach is superior to other algorithms. Applied to suitable test functions and simulations for phosgene, CoSMoS effectively reduces the number of required simulations and real time for the optimization task.
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NASA Astrophysics Data System (ADS)
Li, Yuanyuan; Gao, Guanjun; Zhang, Jie; Zhang, Kai; Chen, Sai; Yu, Xiaosong; Gu, Wanyi
2015-06-01
A simplex-method based optimizing (SMO) strategy is proposed to improve the transmission performance for dispersion uncompensated (DU) coherent optical systems with non-identical spans. Through analytical expression of quality of transmission (QoT), this strategy improves the Q factors effectively, while minimizing the number of erbium-doped optical fiber amplifier (EDFA) that needs to be optimized. Numerical simulations are performed for 100 Gb/s polarization-division multiplexed quadrature phase shift keying (PDM-QPSK) channels over 10-span standard single mode fiber (SSMF) with randomly distributed span-lengths. Compared to the EDFA configurations with complete span loss compensation, the Q factor of the SMO strategy is improved by approximately 1 dB at the optimal transmitter launch power. Moreover, instead of adjusting the gains of all the EDFAs to their optimal value, the number of EDFA that needs to be adjusted for SMO is reduced from 8 to 2, showing much less tuning costs and almost negligible performance degradation.
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Generalized SMO algorithm for SVM-based multitask learning.
Cai, Feng; Cherkassky, Vladimir
2012-06-01
Exploiting additional information to improve traditional inductive learning is an active research area in machine learning. In many supervised-learning applications, training data can be naturally separated into several groups, and incorporating this group information into learning may improve generalization. Recently, Vapnik proposed a general approach to formalizing such problems, known as "learning with structured data" and its support vector machine (SVM) based optimization formulation called SVM+. Liang and Cherkassky showed the connection between SVM+ and multitask learning (MTL) approaches in machine learning, and proposed an SVM-based formulation for MTL called SVM+MTL for classification. Training the SVM+MTL classifier requires the solution of a large quadratic programming optimization problem which scales as O(n(3)) with sample size n. So there is a need to develop computationally efficient algorithms for implementing SVM+MTL. This brief generalizes Platt's sequential minimal optimization (SMO) algorithm to the SVM+MTL setting. Empirical results show that, for typical SVM+MTL problems, the proposed generalized SMO achieves over 100 times speed-up, in comparison with general-purpose optimization routines.
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Working set selection using functional gain for LS-SVM.
Bo, Liefeng; Jiao, Licheng; Wang, Ling
2007-09-01
The efficiency of sequential minimal optimization (SMO) depends strongly on the working set selection. This letter shows how the improvement of SMO in each iteration, named the functional gain (FG), is used to select the working set for least squares support vector machine (LS-SVM). We prove the convergence of the proposed method and give some theoretical support for its performance. Empirical comparisons demonstrate that our method is superior to the maximum violating pair (MVP) working set selection.
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Hazardous Traffic Event Detection Using Markov Blanket and Sequential Minimal Optimization (MB-SMO)
Yan, Lixin; Zhang, Yishi; He, Yi; Gao, Song; Zhu, Dunyao; Ran, Bin; Wu, Qing
2016-01-01
The ability to identify hazardous traffic events is already considered as one of the most effective solutions for reducing the occurrence of crashes. Only certain particular hazardous traffic events have been studied in previous studies, which were mainly based on dedicated video stream data and GPS data. The objective of this study is twofold: (1) the Markov blanket (MB) algorithm is employed to extract the main factors associated with hazardous traffic events; (2) a model is developed to identify hazardous traffic event using driving characteristics, vehicle trajectory, and vehicle position data. Twenty-two licensed drivers were recruited to carry out a natural driving experiment in Wuhan, China, and multi-sensor information data were collected for different types of traffic events. The results indicated that a vehicle’s speed, the standard deviation of speed, the standard deviation of skin conductance, the standard deviation of brake pressure, turn signal, the acceleration of steering, the standard deviation of acceleration, and the acceleration in Z (G) have significant influences on hazardous traffic events. The sequential minimal optimization (SMO) algorithm was adopted to build the identification model, and the accuracy of prediction was higher than 86%. Moreover, compared with other detection algorithms, the MB-SMO algorithm was ranked best in terms of the prediction accuracy. The conclusions can provide reference evidence for the development of dangerous situation warning products and the design of intelligent vehicles. PMID:27420073
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Hazardous Traffic Event Detection Using Markov Blanket and Sequential Minimal Optimization (MB-SMO).
Yan, Lixin; Zhang, Yishi; He, Yi; Gao, Song; Zhu, Dunyao; Ran, Bin; Wu, Qing
2016-07-13
The ability to identify hazardous traffic events is already considered as one of the most effective solutions for reducing the occurrence of crashes. Only certain particular hazardous traffic events have been studied in previous studies, which were mainly based on dedicated video stream data and GPS data. The objective of this study is twofold: (1) the Markov blanket (MB) algorithm is employed to extract the main factors associated with hazardous traffic events; (2) a model is developed to identify hazardous traffic event using driving characteristics, vehicle trajectory, and vehicle position data. Twenty-two licensed drivers were recruited to carry out a natural driving experiment in Wuhan, China, and multi-sensor information data were collected for different types of traffic events. The results indicated that a vehicle's speed, the standard deviation of speed, the standard deviation of skin conductance, the standard deviation of brake pressure, turn signal, the acceleration of steering, the standard deviation of acceleration, and the acceleration in Z (G) have significant influences on hazardous traffic events. The sequential minimal optimization (SMO) algorithm was adopted to build the identification model, and the accuracy of prediction was higher than 86%. Moreover, compared with other detection algorithms, the MB-SMO algorithm was ranked best in terms of the prediction accuracy. The conclusions can provide reference evidence for the development of dangerous situation warning products and the design of intelligent vehicles.
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Spectral Estimation Model Construction of Heavy Metals in Mining Reclamation Areas
Dong, Jihong; Dai, Wenting; Xu, Jiren; Li, Songnian
2016-01-01
The study reported here examined, as the research subject, surface soils in the Liuxin mining area of Xuzhou, and explored the heavy metal content and spectral data by establishing quantitative models with Multivariable Linear Regression (MLR), Generalized Regression Neural Network (GRNN) and Sequential Minimal Optimization for Support Vector Machine (SMO-SVM) methods. The study results are as follows: (1) the estimations of the spectral inversion models established based on MLR, GRNN and SMO-SVM are satisfactory, and the MLR model provides the worst estimation, with R2 of more than 0.46. This result suggests that the stress sensitive bands of heavy metal pollution contain enough effective spectral information; (2) the GRNN model can simulate the data from small samples more effectively than the MLR model, and the R2 between the contents of the five heavy metals estimated by the GRNN model and the measured values are approximately 0.7; (3) the stability and accuracy of the spectral estimation using the SMO-SVM model are obviously better than that of the GRNN and MLR models. Among all five types of heavy metals, the estimation for cadmium (Cd) is the best when using the SMO-SVM model, and its R2 value reaches 0.8628; (4) using the optimal model to invert the Cd content in wheat that are planted on mine reclamation soil, the R2 and RMSE between the measured and the estimated values are 0.6683 and 0.0489, respectively. This result suggests that the method using the SMO-SVM model to estimate the contents of heavy metals in wheat samples is feasible. PMID:27367708
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Spectral Estimation Model Construction of Heavy Metals in Mining Reclamation Areas.
Dong, Jihong; Dai, Wenting; Xu, Jiren; Li, Songnian
2016-06-28
The study reported here examined, as the research subject, surface soils in the Liuxin mining area of Xuzhou, and explored the heavy metal content and spectral data by establishing quantitative models with Multivariable Linear Regression (MLR), Generalized Regression Neural Network (GRNN) and Sequential Minimal Optimization for Support Vector Machine (SMO-SVM) methods. The study results are as follows: (1) the estimations of the spectral inversion models established based on MLR, GRNN and SMO-SVM are satisfactory, and the MLR model provides the worst estimation, with R² of more than 0.46. This result suggests that the stress sensitive bands of heavy metal pollution contain enough effective spectral information; (2) the GRNN model can simulate the data from small samples more effectively than the MLR model, and the R² between the contents of the five heavy metals estimated by the GRNN model and the measured values are approximately 0.7; (3) the stability and accuracy of the spectral estimation using the SMO-SVM model are obviously better than that of the GRNN and MLR models. Among all five types of heavy metals, the estimation for cadmium (Cd) is the best when using the SMO-SVM model, and its R² value reaches 0.8628; (4) using the optimal model to invert the Cd content in wheat that are planted on mine reclamation soil, the R² and RMSE between the measured and the estimated values are 0.6683 and 0.0489, respectively. This result suggests that the method using the SMO-SVM model to estimate the contents of heavy metals in wheat samples is feasible.
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Systematic study of source mask optimization and verification flows
NASA Astrophysics Data System (ADS)
Ben, Yu; Latypov, Azat; Chua, Gek Soon; Zou, Yi
2012-06-01
Source mask optimization (SMO) emerged as powerful resolution enhancement technique (RET) for advanced technology nodes. However, there is a plethora of flow and verification metrics in the field, confounding the end user of the technique. Systemic study of different flows and the possible unification thereof is missing. This contribution is intended to reveal the pros and cons of different SMO approaches and verification metrics, understand the commonality and difference, and provide a generic guideline for RET selection via SMO. The paper discusses 3 different type of variations commonly arise in SMO, namely pattern preparation & selection, availability of relevant OPC recipe for freeform source and finally the metrics used in source verification. Several pattern selection algorithms are compared and advantages of systematic pattern selection algorithms are discussed. In the absence of a full resist model for SMO, alternative SMO flow without full resist model is reviewed. Preferred verification flow with quality metrics of DOF and MEEF is examined.
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The impact of realistic source shape and flexibility on source mask optimization
NASA Astrophysics Data System (ADS)
Aoyama, Hajime; Mizuno, Yasushi; Hirayanagi, Noriyuki; Kita, Naonori; Matsui, Ryota; Izumi, Hirohiko; Tajima, Keiichi; Siebert, Joachim; Demmerle, Wolfgang; Matsuyama, Tomoyuki
2013-04-01
Source mask optimization (SMO) is widely used to make state-of-the-art semiconductor devices in high volume manufacturing. To realize mature SMO solutions in production, the Intelligent Illuminator, which is an illumination system on Nikon scanner, is useful because it can provide generation of freeform sources with high fidelity to the target. Proteus SMO, which employs co-optimization method and an insertion of validation with mask 3D effect and resist properties for an accurate prediction of wafer printing, can take into account the properties of Intelligent Illuminator. We investigate an impact of the source properties on the SMO to pattern of a static-random access memory. Quality of a source made on the scanner compared to the SMO target is evaluated with in-situ measurement and aerial image simulation using its measurement data. Furthermore we discuss an evaluation of a universality of the source to use it in multiple scanners with a validation with estimated value of scanner errors.
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CFS-SMO based classification of breast density using multiple texture models.
Sharma, Vipul; Singh, Sukhwinder
2014-06-01
It is highly acknowledged in the medical profession that density of breast tissue is a major cause for the growth of breast cancer. Increased breast density was found to be linked with an increased risk of breast cancer growth, as high density makes it difficult for radiologists to see an abnormality which leads to false negative results. Therefore, there is need for the development of highly efficient techniques for breast tissue classification based on density. This paper presents a hybrid scheme for classification of fatty and dense mammograms using correlation-based feature selection (CFS) and sequential minimal optimization (SMO). In this work, texture analysis is done on a region of interest selected from the mammogram. Various texture models have been used to quantify the texture of parenchymal patterns of breast. To reduce the dimensionality and to identify the features which differentiate between breast tissue densities, CFS is used. Finally, classification is performed using SMO. The performance is evaluated using 322 images of mini-MIAS database. Highest accuracy of 96.46% is obtained for two-class problem (fatty and dense) using proposed approach. Performance of selected features by CFS is also evaluated by Naïve Bayes, Multilayer Perceptron, RBF Network, J48 and kNN classifier. The proposed CFS-SMO method outperforms all other classifiers giving a sensitivity of 100%. This makes it suitable to be taken as a second opinion in classifying breast tissue density.
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NASA Astrophysics Data System (ADS)
Zhu, Jun; Zhang, David Wei; Kuo, Chinte; Wang, Qing; Wei, Fang; Zhang, Chenming; Chen, Han; He, Daquan; Hsu, Stephen D.
2017-07-01
As technology node shrinks, aggressive design rules for contact and other back end of line (BEOL) layers continue to drive the need for more effective full chip patterning optimization. Resist top loss is one of the major challenges for 28 nm and below technology nodes, which can lead to post-etch hotspots that are difficult to predict and eventually degrade the process window significantly. To tackle this problem, we used an advanced programmable illuminator (FlexRay) and Tachyon SMO (Source Mask Optimization) platform to make resistaware source optimization possible, and it is proved to greatly improve the imaging contrast, enhance focus and exposure latitude, and minimize resist top loss thus improving the yield.
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NASA Astrophysics Data System (ADS)
Wu, Huaping; Ma, Xuefu; Zhang, Zheng; Zhu, Jun; Wang, Jie; Chai, Guozhong
2016-04-01
A nonlinear thermodynamic model based on the vertically aligned nanocomposite (VAN) thin films of ferroelectric-metal oxide system has been developed to investigate the physical properties of the epitaxial Ba0.6Sr0.4TiO3 (BST) films containing vertical Sm2O3 (SmO) nanopillar arrays on the SrTiO3 substrate. The phase diagrams of out-of-plane lattice mismatch vs. volume fraction of SmO are calculated by minimizing the total free energy. It is found that the phase transformation and dielectric response of BST-SmO VAN systems are extremely dependent on the in-plane misfit strain, the out-of-plane lattice mismatch, the volume fraction of SmO phase, and the external electric field applied to the nanocomposite films at room temperature. In particular, the BST-SmO VAN systems exhibit higher dielectric properties than pure BST films. Giant dielectric response and maximum tunability are obtained near the lattice mismatch where the phase transition occurs. Under the in-plane misfit strain of umf=0.3 % and the out-of-plane lattice mismatch of u3=0.002 , the dielectric tunability can be dramatically enhanced to 90% with the increase of SmO volume fraction, which is well consistent with previous experimental results. This work represents an approach to further understand the dependence of physical properties on the lattice mismatch (in-plane and out-of-plane) and volume fraction, and to manipulate or optimize functionalities in the nanocomposite oxide thin films.
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Li, Jia; Lam, Edmund Y
2014-04-21
Mask topography effects need to be taken into consideration for a more accurate solution of source mask optimization (SMO) in advanced optical lithography. However, rigorous 3D mask models generally involve intensive computation and conventional SMO fails to manipulate the mask-induced undesired phase errors that degrade the usable depth of focus (uDOF) and process yield. In this work, an optimization approach incorporating pupil wavefront aberrations into SMO procedure is developed as an alternative to maximize the uDOF. We first design the pupil wavefront function by adding primary and secondary spherical aberrations through the coefficients of the Zernike polynomials, and then apply the conjugate gradient method to achieve an optimal source-mask pair under the condition of aberrated pupil. We also use a statistical model to determine the Zernike coefficients for the phase control and adjustment. Rigorous simulations of thick masks show that this approach provides compensation for mask topography effects by improving the pattern fidelity and increasing uDOF.
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Torija, Antonio J; Ruiz, Diego P; Ramos-Ridao, Angel F
2014-06-01
To ensure appropriate soundscape management in urban environments, the urban-planning authorities need a range of tools that enable such a task to be performed. An essential step during the management of urban areas from a sound standpoint should be the evaluation of the soundscape in such an area. In this sense, it has been widely acknowledged that a subjective and acoustical categorization of a soundscape is the first step to evaluate it, providing a basis for designing or adapting it to match people's expectations as well. In this sense, this work proposes a model for automatic classification of urban soundscapes. This model is intended for the automatic classification of urban soundscapes based on underlying acoustical and perceptual criteria. Thus, this classification model is proposed to be used as a tool for a comprehensive urban soundscape evaluation. Because of the great complexity associated with the problem, two machine learning techniques, Support Vector Machines (SVM) and Support Vector Machines trained with Sequential Minimal Optimization (SMO), are implemented in developing model classification. The results indicate that the SMO model outperforms the SVM model in the specific task of soundscape classification. With the implementation of the SMO algorithm, the classification model achieves an outstanding performance (91.3% of instances correctly classified). © 2013 Elsevier B.V. All rights reserved.
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NASA Astrophysics Data System (ADS)
Goienetxea Uriarte, A.; Ruiz Zúñiga, E.; Urenda Moris, M.; Ng, A. H. C.
2015-05-01
Discrete Event Simulation (DES) is nowadays widely used to support decision makers in system analysis and improvement. However, the use of simulation for improving stochastic logistic processes is not common among healthcare providers. The process of improving healthcare systems involves the necessity to deal with trade-off optimal solutions that take into consideration a multiple number of variables and objectives. Complementing DES with Multi-Objective Optimization (SMO) creates a superior base for finding these solutions and in consequence, facilitates the decision-making process. This paper presents how SMO has been applied for system improvement analysis in a Swedish Emergency Department (ED). A significant number of input variables, constraints and objectives were considered when defining the optimization problem. As a result of the project, the decision makers were provided with a range of optimal solutions which reduces considerably the length of stay and waiting times for the ED patients. SMO has proved to be an appropriate technique to support healthcare system design and improvement processes. A key factor for the success of this project has been the involvement and engagement of the stakeholders during the whole process.
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Lu, Wenfeng; Zhang, Dihua; Ma, Haikuo; Tian, Sheng; Zheng, Jiyue; Wang, Qin; Luo, Lusong; Zhang, Xiaohu
2018-05-23
The Hedgehog (Hh) signaling pathway plays a critical role in controlling patterning, growth and cell migration during embryonic development. Aberrant activation of Hh signaling has been linked to tumorigenesis in various cancers, such as basal cell carcinoma (BCC) and medulloblastoma. As a key member of the Hh pathway, the Smoothened (Smo) receptor, a member of the G protein-coupled receptor (GPCR) family, has emerged as an attractive therapeutic target for the treatment and prevention of human cancers. The recent determination of several crystal structures of Smo in complex with different antagonists offers the possibility to perform structure-based virtual screening for discovering potent Smo antagonists with distinct chemical scaffolds. In this study, based on the two Smo crystal complexes with the best capacity to distinguish the known Smo antagonists from decoys, the molecular docking-based virtual screening was conducted to identify promising Smo antagonists from ChemDiv library. A total of 21 structurally novel and diverse compounds were selected for experimental testing, and six of them exhibited significant inhibitory activity against the Hh pathway activation (IC 50 < 10 μM) in a GRE (Gli-responsive element) reporter gene assay. Specifically, the most potent compound (compound 20: 47 nM) showed comparable Hh signaling inhibition to vismodegib (46 nM). Compound 20 was further confirmed to be a potent Smo antagonist in a fluorescence based competitive binding assay. Optimization using substructure searching method led to the discovery of 12 analogues of compound 20 with decent Hh pathway inhibition activity, including four compounds with IC 50 lower than 1 μM. The important residues uncovered by binding free energy calculation (MM/GBSA) and binding free energy decomposition were highlighted and discussed. These findings suggest that the novel scaffold afforded by compound 20 can be used as a good starting point for further modification/optimization and the clarified interaction patterns may also guide us to find more potent Smo antagonists. Copyright © 2018 Elsevier Masson SAS. All rights reserved.
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Extension of optical lithography by mask-litho integration with computational lithography
NASA Astrophysics Data System (ADS)
Takigawa, T.; Gronlund, K.; Wiley, J.
2010-05-01
Wafer lithography process windows can be enlarged by using source mask co-optimization (SMO). Recently, SMO including freeform wafer scanner illumination sources has been developed. Freeform sources are generated by a programmable illumination system using a micro-mirror array or by custom Diffractive Optical Elements (DOE). The combination of freeform sources and complex masks generated by SMO show increased wafer lithography process window and reduced MEEF. Full-chip mask optimization using source optimized by SMO can generate complex masks with small variable feature size sub-resolution assist features (SRAF). These complex masks create challenges for accurate mask pattern writing and low false-defect inspection. The accuracy of the small variable-sized mask SRAF patterns is degraded by short range mask process proximity effects. To address the accuracy needed for these complex masks, we developed a highly accurate mask process correction (MPC) capability. It is also difficult to achieve low false-defect inspections of complex masks with conventional mask defect inspection systems. A printability check system, Mask Lithography Manufacturability Check (M-LMC), is developed and integrated with 199-nm high NA inspection system, NPI. M-LMC successfully identifies printable defects from all of the masses of raw defect images collected during the inspection of a complex mask. Long range mask CD uniformity errors are compensated by scanner dose control. A mask CD uniformity error map obtained by mask metrology system is used as input data to the scanner. Using this method, wafer CD uniformity is improved. As reviewed above, mask-litho integration technology with computational lithography is becoming increasingly important.
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Wang, Yu; Zhang, Yaonan; Yao, Zhaomin; Zhao, Ruixue; Zhou, Fengfeng
2016-01-01
Non-lethal macular diseases greatly impact patients’ life quality, and will cause vision loss at the late stages. Visual inspection of the optical coherence tomography (OCT) images by the experienced clinicians is the main diagnosis technique. We proposed a computer-aided diagnosis (CAD) model to discriminate age-related macular degeneration (AMD), diabetic macular edema (DME) and healthy macula. The linear configuration pattern (LCP) based features of the OCT images were screened by the Correlation-based Feature Subset (CFS) selection algorithm. And the best model based on the sequential minimal optimization (SMO) algorithm achieved 99.3% in the overall accuracy for the three classes of samples. PMID:28018716
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Power law-based local search in spider monkey optimisation for lower order system modelling
NASA Astrophysics Data System (ADS)
Sharma, Ajay; Sharma, Harish; Bhargava, Annapurna; Sharma, Nirmala
2017-01-01
The nature-inspired algorithms (NIAs) have shown efficiency to solve many complex real-world optimisation problems. The efficiency of NIAs is measured by their ability to find adequate results within a reasonable amount of time, rather than an ability to guarantee the optimal solution. This paper presents a solution for lower order system modelling using spider monkey optimisation (SMO) algorithm to obtain a better approximation for lower order systems and reflects almost original higher order system's characteristics. Further, a local search strategy, namely, power law-based local search is incorporated with SMO. The proposed strategy is named as power law-based local search in SMO (PLSMO). The efficiency, accuracy and reliability of the proposed algorithm is tested over 20 well-known benchmark functions. Then, the PLSMO algorithm is applied to solve the lower order system modelling problem.
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Sterol Methyl Oxidases Affect Embryo Development via Auxin-Associated Mechanisms.
Zhang, Xia; Sun, Shuangli; Nie, Xiang; Boutté, Yohann; Grison, Magali; Li, Panpan; Kuang, Susu; Men, Shuzhen
2016-05-01
Sterols are essential molecules for multiple biological processes, including embryogenesis, cell elongation, and endocytosis. The plant sterol biosynthetic pathway is unique in the involvement of two distinct sterol 4α-methyl oxidase (SMO) families, SMO1 and SMO2, which contain three and two isoforms, respectively, and are involved in sequential removal of the two methyl groups at C-4. In this study, we characterized the biological functions of members of the SMO2 gene family. SMO2-1 was strongly expressed in most tissues during Arabidopsis (Arabidopsis thaliana) development, whereas SMO2-2 showed a more specific expression pattern. Although single smo2 mutants displayed no obvious phenotype, the smo2-1 smo2-2 double mutant was embryonic lethal, and the smo2-1 smo2-2/+ mutant was dwarf, whereas the smo2-1/+ smo2-2 mutant exhibited a moderate phenotype. The phenotypes of the smo2 mutants resembled those of auxin-defective mutants. Indeed, the expression of DR5rev:GFP, an auxin-responsive reporter, was reduced and abnormal in smo2-1 smo2-2 embryos. Furthermore, the expression and subcellular localization of the PIN1 auxin efflux facilitator also were altered. Consistent with these observations, either the exogenous application of auxin or endogenous auxin overproduction (YUCCA9 overexpression) partially rescued the smo2-1 smo2-2 embryonic lethality. Surprisingly, the dwarf phenotype of smo2-1 smo2-2/+ was completely rescued by YUCCA9 overexpression. Gas chromatography-mass spectrometry analysis revealed a substantial accumulation of 4α-methylsterols, substrates of SMO2, in smo2 heterozygous double mutants. Together, our data suggest that SMO2s are important for correct sterol composition and function partially through effects on auxin accumulation, auxin response, and PIN1 expression to regulate Arabidopsis embryogenesis and postembryonic development. © 2016 American Society of Plant Biologists. All Rights Reserved.
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Sterol Methyl Oxidases Affect Embryo Development via Auxin-Associated Mechanisms1
Zhang, Xia; Sun, Shuangli; Nie, Xiang; Boutté, Yohann; Grison, Magali; Li, Panpan; Kuang, Susu
2016-01-01
Sterols are essential molecules for multiple biological processes, including embryogenesis, cell elongation, and endocytosis. The plant sterol biosynthetic pathway is unique in the involvement of two distinct sterol 4α-methyl oxidase (SMO) families, SMO1 and SMO2, which contain three and two isoforms, respectively, and are involved in sequential removal of the two methyl groups at C-4. In this study, we characterized the biological functions of members of the SMO2 gene family. SMO2-1 was strongly expressed in most tissues during Arabidopsis (Arabidopsis thaliana) development, whereas SMO2-2 showed a more specific expression pattern. Although single smo2 mutants displayed no obvious phenotype, the smo2-1 smo2-2 double mutant was embryonic lethal, and the smo2-1 smo2-2/+ mutant was dwarf, whereas the smo2-1/+ smo2-2 mutant exhibited a moderate phenotype. The phenotypes of the smo2 mutants resembled those of auxin-defective mutants. Indeed, the expression of DR5rev:GFP, an auxin-responsive reporter, was reduced and abnormal in smo2-1 smo2-2 embryos. Furthermore, the expression and subcellular localization of the PIN1 auxin efflux facilitator also were altered. Consistent with these observations, either the exogenous application of auxin or endogenous auxin overproduction (YUCCA9 overexpression) partially rescued the smo2-1 smo2-2 embryonic lethality. Surprisingly, the dwarf phenotype of smo2-1 smo2-2/+ was completely rescued by YUCCA9 overexpression. Gas chromatography-mass spectrometry analysis revealed a substantial accumulation of 4α-methylsterols, substrates of SMO2, in smo2 heterozygous double mutants. Together, our data suggest that SMO2s are important for correct sterol composition and function partially through effects on auxin accumulation, auxin response, and PIN1 expression to regulate Arabidopsis embryogenesis and postembryonic development. PMID:27006488
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The Smo/Smo model: hedgehog-induced medulloblastoma with 90% incidence and leptomeningeal spread.
Hatton, Beryl A; Villavicencio, Elisabeth H; Tsuchiya, Karen D; Pritchard, Joel I; Ditzler, Sally; Pullar, Barbara; Hansen, Stacey; Knoblaugh, Sue E; Lee, Donghoon; Eberhart, Charles G; Hallahan, Andrew R; Olson, James M
2008-03-15
Toward the goal of generating a mouse medulloblastoma model with increased tumor incidence, we developed a homozygous version of our ND2:SmoA1 model. Medulloblastomas form in 94% of homozygous Smo/Smo mice by 2 months of age. Tumor formation is, thus, predictable by age, before the symptomatic appearance of larger lesions. This high incidence and early onset of tumors is ideal for preclinical studies because mice can be enrolled before symptom onset and with a greater latency period before late-stage disease. Smo/Smo tumors also display leptomeningeal dissemination of neoplastic cells to the brain and spine, which occurs in many human cases. Despite an extended proliferation of granule neuron precursors (GNP) in the postnatal external granular layer (EGL), the internal granular layer formed normally in Smo/Smo mice and tumor formation occurred only in localized foci on the superficial surface of the molecular layer. Thus, tumor formation is not simply the result of over proliferation of GNPs within the EGL. Moreover, Smo/Smo medulloblastomas were transplantable and serially passaged in vivo, demonstrating the aggressiveness of tumor cells and their transformation beyond a hyperplastic state. The Smo/Smo model is the first mouse medulloblastoma model to show leptomeningeal spread. The adherence to human pathology, high incidence, and early onset of tumors thus make Smo/Smo mice an efficient model for preclinical studies.
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Heterologous expression and characterization of mouse spermine oxidase.
Cervelli, Manuela; Polticelli, Fabio; Federico, Rodolfo; Mariottini, Paolo
2003-02-14
Polyamine oxidases are key enzymes responsible of the polyamine interconversion metabolism in animal cells. Recently, a novel enzyme belonging to this class of enzymes has been characterized for its capability to oxidize preferentially spermine and designated as spermine oxidase. This is a flavin adenine dinucleotide-containing enzyme, and it has been expressed both in vitro and in vivo systems. The primary structure of mouse spermine oxidase (mSMO) was deduced from a cDNA clone (Image Clone 264769) recovered by a data base search utilizing the human counterpart of polyamine oxidases, PAOh1. The open reading frame predicts a 555-amino acid protein with a calculated M(r) of 61,852.30, which shows a 95.1% identity with PAOh1. To understand the biochemical properties of mSMO and its structure/function relationship, the mSMO cDNA has been subcloned and expressed in secreted and secreted-tagged forms into Escherichia coli BL21 DE3 cells. The recombinant enzyme shows an optimal pH value of 8.0 and is able to oxidize rapidly spermine to spermidine and 3-aminopropanal and fails to act upon spermidine and N(1)-acetylpolyamines. The purified recombinant-tagged form enzyme (M(r) approximately 68,000) has K(m) and k(cat) values of 90 microm and 4.5 s(-1), respectively, using spermine as substrate at pH 8.0. Molecular modeling of mSMO protein based on maize polyamine oxidase three-dimensional structure suggests that the general features of maize polyamine oxidase active site are conserved in mSMO.
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NASA Astrophysics Data System (ADS)
Xu, Xia; Shi, Zhenwei; Pan, Bin
2018-07-01
Sparse unmixing aims at recovering pure materials from hyperpspectral images and estimating their abundance fractions. Sparse unmixing is actually ℓ0 problem which is NP-h ard, and a relaxation is often used. In this paper, we attempt to deal with ℓ0 problem directly via a multi-objective based method, which is a non-convex manner. The characteristics of hyperspectral images are integrated into the proposed method, which leads to a new spectra and multi-objective based sparse unmixing method (SMoSU). In order to solve the ℓ0 norm optimization problem, the spectral library is encoded in a binary vector, and a bit-wise flipping strategy is used to generate new individuals in the evolution process. However, a multi-objective method usually produces a number of non-dominated solutions, while sparse unmixing requires a single solution. How to make the final decision for sparse unmixing is challenging. To handle this problem, we integrate the spectral characteristic of hyperspectral images into SMoSU. By considering the spectral correlation in hyperspectral data, we improve the Tchebycheff decomposition function in SMoSU via a new regularization item. This regularization item is able to enforce the individual divergence in the evolution process of SMoSU. In this way, the diversity and convergence of population is further balanced, which is beneficial to the concentration of individuals. In the experiments part, three synthetic datasets and one real-world data are used to analyse the effectiveness of SMoSU, and several state-of-art sparse unmixing algorithms are compared.
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Cervelli, Manuela; Bellavia, Gabriella; Fratini, Emiliano; Amendola, Roberto; Polticelli, Fabio; Barba, Marco; Federico, Rodolfo; Signore, Fabrizio; Gucciardo, Giacomo; Grillo, Rosalba; Woster, Patrick M; Casero, Robert A; Mariottini, Paolo
2010-10-14
Polyamine metabolism has a critical role in cell death and proliferation representing a potential target for intervention in breast cancer (BC). This study investigates the expression of spermine oxidase (SMO) and its prognostic significance in BC. Biochemical analysis of Spm analogues BENSpm and CPENSpm, utilized in anticancer therapy, was also carried out to test their property in silico and in vitro on the recombinant SMO enzyme. BC tissue samples were analyzed for SMO transcript level and SMO activity. Student's t test was applied to evaluate the significance of the differences in value observed in T and NT samples. The structure modeling analysis of BENSpm and CPENSpm complexes formed with the SMO enzyme and their inhibitory activity, assayed by in vitro experiments, were examined. Both the expression level of SMO mRNA and SMO enzyme activity were significantly lower in BC samples compared to NT samples. The modeling of BENSpm and CPENSpm complexes formed with SMO and their inhibition properties showed that both were good inhibitors. This study shows that underexpression of SMO is a negative marker in BC. The SMO induction is a remarkable chemotherapeutical target. The BENSpm and CPENSpm are efficient SMO inhibitors. The inhibition properties shown by these analogues could explain their poor positive outcomes in Phases I and II of clinical trials.
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2010-01-01
Background Polyamine metabolism has a critical role in cell death and proliferation representing a potential target for intervention in breast cancer (BC). This study investigates the expression of spermine oxidase (SMO) and its prognostic significance in BC. Biochemical analysis of Spm analogues BENSpm and CPENSpm, utilized in anticancer therapy, was also carried out to test their property in silico and in vitro on the recombinant SMO enzyme. Methods BC tissue samples were analyzed for SMO transcript level and SMO activity. Student's t test was applied to evaluate the significance of the differences in value observed in T and NT samples. The structure modeling analysis of BENSpm and CPENSpm complexes formed with the SMO enzyme and their inhibitory activity, assayed by in vitro experiments, were examined. Results Both the expression level of SMO mRNA and SMO enzyme activity were significantly lower in BC samples compared to NT samples. The modeling of BENSpm and CPENSpm complexes formed with SMO and their inhibition properties showed that both were good inhibitors. Conclusions This study shows that underexpression of SMO is a negative marker in BC. The SMO induction is a remarkable chemotherapeutical target. The BENSpm and CPENSpm are efficient SMO inhibitors. The inhibition properties shown by these analogues could explain their poor positive outcomes in Phases I and II of clinical trials. PMID:20946629
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METABOLISM OF N-ALKYLATED SPERMINE ANALOGUES BY POLYAMINE AND SPERMINE OXIDASES
Häkkinen, Merja R.; Hyvönen, Mervi T.; Auriola, Seppo; Casero, Robert A.; Vepsäläinen, Jouko; Khomutov, Alex R.; Alhonen, Leena; Keinänen, Tuomo A.
2010-01-01
SUMMARY N-alkylated polyamine analogues have potential as anticancer and antiparasitic drugs. However, their metabolism in the host has remained incompletely defined thus potentially limiting their utility. Here, we have studied the degradation of three different spermine analogues N,N′-bis-(3-ethylaminopropyl)butane-1,4-diamine (DESPM), N-(3-benzyl-aminopropyl)-N'-(3-ethylaminopropyl)butane-1,4-diamine (BnEtSPM) and N,N′-bis-(3-benzylaminopropyl)butane-1,4-diamine (DBSPM) and related mono-alkylated derivatives as substrates of recombinant human polyamine oxidase (APAO) and spermine oxidase (SMO). APAO and SMO metabolized DESPM to EtSPD (Km(APAO)=10μM, kcat(APAO)=1.1s−1 and Km(SMO)=28μM, kcat(SMO)=0.8s−1, respectively), metabolized BnEtSPM to EtSPD (Km(APAO)=0.9 μM, kcat(APAO)=1.1s−1 and Km(SMO)=51μM, kcat(SMO)=0.4s−1, respectively), and metabolized DBSPM to BnSPD (Km(APAO)=5.4μM, kcat(APAO)= 2.0s−1 and Km(SMO)=33μM, kcat(SMO)=0.3s−1, respectively). Interestingly, mono-alkylated spermine derivatives were metabolized by APAO and SMO to SPD (EtSPM Km(APAO)=16μM, kcat(APAO)=1.5s−1; Km(SMO)=25μM, kcat(SMO) =8.2s−1; BnSPM Km(APAO)=6.0μM, kcat(APAO)=2.8s−1; Km(SMO)=19μM, kcat(SMO)=0.8s−1, respectively). Surprisingly, E t S P D ( Km(APAO)=37μM, kcat(APAO)=0.1s−1; Km(SMO)=48μM, kcat(SMO)=0.05s−1) and BnSPD (Km(APAO)=2.5μM, kcat(APAO)=3.5s−1; Km(SMO)=60μM, kcat(SMO)=0.54s−1) were metabolized to SPD by both the oxidases. Furthermore, we studied the degradation of DESPM, BnEtSPM or DBSPM in the DU145 prostate carcinoma cell line. The same major metabolites EtSPD and/or BnSPD were detected both in the culture medium and intracellularly after 48 hours of culture. Moreover, EtSPM and BnSPM were detected from cell samples. Present data shows that inducible SMO parallel with APAO could play an important role in polyamine based drug action, i.e. degradation of parent drug and its metabolites, having significant impact on efficiency of these drugs, and hence for the development of novel N-alkylated polyamine analogues. PMID:20012116
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Identifying typical physical activity on smartphone with varying positions and orientations.
Miao, Fen; He, Yi; Liu, Jinlei; Li, Ye; Ayoola, Idowu
2015-04-13
Traditional activity recognition solutions are not widely applicable due to a high cost and inconvenience to use with numerous sensors. This paper aims to automatically recognize physical activity with the help of the built-in sensors of the widespread smartphone without any limitation of firm attachment to the human body. By introducing a method to judge whether the phone is in a pocket, we investigated the data collected from six positions of seven subjects, chose five signals that are insensitive to orientation for activity classification. Decision trees (J48), Naive Bayes and Sequential minimal optimization (SMO) were employed to recognize five activities: static, walking, running, walking upstairs and walking downstairs. The experimental results based on 8,097 activity data demonstrated that the J48 classifier produced the best performance with an average recognition accuracy of 89.6% during the three classifiers, and thus would serve as the optimal online classifier. The utilization of the built-in sensors of the smartphone to recognize typical physical activities without any limitation of firm attachment is feasible.
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NASA Astrophysics Data System (ADS)
Weichman, Marissa L.; Vlaisavljevich, Bess; DeVine, Jessalyn A.; Shuman, Nicholas S.; Ard, Shaun G.; Shiozaki, Toru; Neumark, Daniel M.; Viggiano, Albert A.
2017-12-01
The chemi-ionization reaction of atomic samarium, Sm + O → SmO+ + e-, has been investigated by the Air Force Research Laboratory as a means to modify local electron density in the ionosphere for reduction of scintillation of high-frequency radio waves. Neutral SmO is a likely unwanted byproduct. The spectroscopy of SmO is of great interest to aid in interpretation of optical emission spectra recorded following atmospheric releases of Sm as part of the Metal Oxide Space Cloud (MOSC) observations. Here, we report a joint experimental and theoretical study of SmO using slow photoelectron velocity-map imaging spectroscopy of cryogenically cooled SmO- anions (cryo-SEVI) and high-level spin-orbit complete active space calculations with corrections from second order perturbation theory (CASPT2). With cryo-SEVI, we measure the electron affinity of SmO to be 1.0581(11) eV and report electronic and vibrational structure of low-lying electronic states of SmO in good agreement with theory and prior experimental work. We also obtain spectra of higher-lying excited states of SmO for direct comparison to the MOSC results.
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Martin, Kiri E.; Ozsvar, Jazmin
2014-01-01
Monooxygenase (MO) enzymes initiate the aerobic oxidation of alkanes and alkenes in bacteria. A cluster of MO genes (smoXYB1C1Z) of thus-far-unknown function was found previously in the genomes of two Mycobacterium strains (NBB3 and NBB4) which grow on hydrocarbons. The predicted Smo enzymes have only moderate amino acid identity (30 to 60%) to their closest homologs, the soluble methane and butane MOs (sMMO and sBMO), and the smo gene cluster has a different organization from those of sMMO and sBMO. The smoXYB1C1Z genes of NBB4 were cloned into pMycoFos to make pSmo, which was transformed into Mycobacterium smegmatis mc2-155. Cells of mc2-155(pSmo) metabolized C2 to C4 alkanes, alkenes, and chlorinated hydrocarbons. The activities of mc2-155(pSmo) cells were 0.94, 0.57, 0.12, and 0.04 nmol/min/mg of protein with ethene, ethane, propane, and butane as substrates, respectively. The mc2-155(pSmo) cells made epoxides from ethene, propene, and 1-butene, confirming that Smo was an oxygenase. Epoxides were not produced from larger alkenes (1-octene and styrene). Vinyl chloride and 1,2-dichloroethane were biodegraded by cells expressing Smo, with production of inorganic chloride. This study shows that Smo is a functional oxygenase which is active against small hydrocarbons. M. smegmatis mc2-155(pSmo) provides a new model for studying sMMO-like monooxygenases. PMID:25015887
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Evaluation of Semi-supervised Learning for Classification of Protein Crystallization Imagery.
Sigdel, Madhav; Dinç, İmren; Dinç, Semih; Sigdel, Madhu S; Pusey, Marc L; Aygün, Ramazan S
2014-03-01
In this paper, we investigate the performance of two wrapper methods for semi-supervised learning algorithms for classification of protein crystallization images with limited labeled images. Firstly, we evaluate the performance of semi-supervised approach using self-training with naïve Bayesian (NB) and sequential minimum optimization (SMO) as the base classifiers. The confidence values returned by these classifiers are used to select high confident predictions to be used for self-training. Secondly, we analyze the performance of Yet Another Two Stage Idea (YATSI) semi-supervised learning using NB, SMO, multilayer perceptron (MLP), J48 and random forest (RF) classifiers. These results are compared with the basic supervised learning using the same training sets. We perform our experiments on a dataset consisting of 2250 protein crystallization images for different proportions of training and test data. Our results indicate that NB and SMO using both self-training and YATSI semi-supervised approaches improve accuracies with respect to supervised learning. On the other hand, MLP, J48 and RF perform better using basic supervised learning. Overall, random forest classifier yields the best accuracy with supervised learning for our dataset.
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Plant sterol biosynthesis: identification of two distinct families of sterol 4alpha-methyl oxidases.
Darnet, Sylvain; Rahier, Alain
2004-01-01
In plants, the conversion of cycloartenol into functional phytosterols requires the removal of the two methyl groups at C-4 by an enzymic complex including a sterol 4alpha-methyl oxidase (SMO). We report the cloning of candidate genes for SMOs in Arabidopsis thaliana, belonging to two distinct families termed SMO1 and SMO2 and containing three and two isoforms respectively. SMO1 and SMO2 shared low sequence identity with each other and were orthologous to the ERG25 gene from Saccharomyces cerevisiae which encodes the SMO. The plant SMO amino acid sequences possess all the three histidine-rich motifs (HX3H, HX2HH and HX2HH), characteristic of the small family of membrane-bound non-haem iron oxygenases that are involved in lipid oxidation. To elucidate the precise functions of SMO1 and SMO2 gene families, we have reduced their expression by using a VIGS (virus-induced gene silencing) approach in Nicotiana benthamiana. SMO1 and SMO2 cDNA fragments were inserted into a viral vector and N. benthamiana inoculated with the viral transcripts. After silencing with SMO1, a substantial accumulation of 4,4-dimethyl-9beta,19-cyclopropylsterols (i.e. 24-methylenecycloartanol) was obtained, whereas qualitative and quantitative levels of 4alpha-methylsterols were not affected. In the case of silencing with SMO2, a large accumulation of 4alpha-methyl-Delta7-sterols (i.e. 24-ethylidenelophenol and 24-ethyllophenol) was found, with no change in the levels of 4,4-dimethylsterols. These clear and distinct biochemical phenotypes demonstrate that, in contrast with animals and fungi, in photosynthetic eukaryotes, these two novel families of cDNAs are coding two distinct types of C-4-methylsterol oxidases controlling the level of 4,4-dimethylsterol and 4alpha-methylsterol precursors respectively. PMID:14653780
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Structural basis for Smoothened receptor modulation and chemoresistance to anti-cancer drugs
Wang, Chong; Wu, Huixian; Evron, Tama; Vardy, Eyal; Han, Gye Won; Huang, Xi-Ping; Hufeisen, Sandy J.; Mangano, Thomas J.; Urban, Dan J.; Katritch, Vsevolod; Cherezov, Vadim; Caron, Marc G.; Roth, Bryan L.; Stevens, Raymond C.
2014-01-01
The Smoothened receptor (SMO) mediates signal transduction in the hedgehog pathway, which is implicated in normal development and carcinogenesis. SMO antagonists can suppress the growth of some tumors; however, mutations at SMO have been found to abolish their anti-tumor effects, a phenomenon known as chemoresistance. Here we report three crystal structures of human SMO bound to the antagonists SANT1 and Anta XV, and the agonist, SAG1.5, at 2.6–2.8Å resolution. The long and narrow cavity in the transmembrane domain of SMO harbors multiple ligand binding sites, where SANT1 binds at a deeper site as compared with other ligands. Distinct interactions at D4736.55 elucidated the structural basis for the differential effects of chemoresistance mutations on SMO antagonists. The agonist SAG1.5 induces a conformational rearrangement of the binding pocket residues, which could contribute to SMO activation. Collectively, these studies reveal the structural basis for the modulation of SMO by small molecules. PMID:25008467
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Zhang, Jie; Li, Xiang-An; Evers, B. Mark; Zhu, Haining; Jia, Jianhang
2016-01-01
In Hedgehog (Hh) signaling, binding of Hh to the Patched-Interference Hh (Ptc-Ihog) receptor complex relieves Ptc inhibition on Smoothened (Smo). A longstanding question is how Ptc inhibits Smo and how such inhibition is relieved by Hh stimulation. In this study, we found that Hh elevates production of phosphatidylinositol 4-phosphate (PI(4)P). Increased levels of PI(4)P promote, whereas decreased levels of PI(4)P inhibit, Hh signaling activity. We further found that PI(4)P directly binds Smo through an arginine motif, which then triggers Smo phosphorylation and activation. Moreover, we identified the pleckstrin homology (PH) domain of G protein-coupled receptor kinase 2 (Gprk2) as an essential component for enriching PI(4)P and facilitating Smo activation. PI(4)P also binds mouse Smo (mSmo) and promotes its phosphorylation and ciliary accumulation. Finally, Hh treatment increases the interaction between Smo and PI(4)P but decreases the interaction between Ptc and PI(4)P, indicating that, in addition to promoting PI(4)P production, Hh regulates the pool of PI(4)P associated with Ptc and Smo. PMID:26863604
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Antineoplastic Efficacy of Novel Polyamine Analogues in Human Breast Cancer
2006-06-01
Davidson, N.E., and Casero, R.A.. Spermine oxidase SMO(PAOh1), not N1-acetylpolyamine oxidase (PAO) is the primary source of cytotoxic H2O2 in...human spermine oxidase SMO(PAOh1). SMO(PAOh1) uses unacetylated spermine as substrate and is inducible by specific polyamine analogs [15,16]. These...technique to find the identical clone termed spermine oxidase (SMO) [16]. The function of SMO(PAOh1) as a spermine oxidase has been confirmed [15,67,68
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Pross, Nathalie; Patat, Alain; Vivet, Philippe; Bidaut, Michelle; Fauchoux, Nicolas
2015-01-01
Aim The pharmacologic effects of sodium oxybate (SO) have a number of similarities with those of alcohol. This study evaluated the pharmacodynamic interaction of SMO.IR (a solid immediate release formulation of SO) and alcohol (0.7 (males) or 0.57 (females) g kg–1 alcohol using 40% vodka). Methods In a randomized, double-blind, double-dummy, crossover trial, 24 healthy volunteers received randomly a) 2.25 g SMO.IR and placebo alcohol preparation, b) 2.25 g f SMO.IR and alcohol, c) 2.25 g SMO.IR matching placebo and alcohol and d) 2.25 g of SMO.IR matching placebo and placebo alcohol preparation. Objective and subjective cognitive parameters, adverse events and vital signs were assessed before, 15 and 165 min after treatment administration. Results Alcohol produced the expected cognitive impairment and the expected subjective sedation rapidly after intake (from 15 min). The objective effects of SMO.IR were much less pronounced than those of alcohol. The reverse was observed for subjective complaints, which were related to lesser stimulation and greater sedation. Nevertheless, 165 min after administration this sedation feeling was less with SMO.IR than with alcohol. There was a significant interaction between SMO.IR and alcohol at 15 min (i.e. increase in alertness and stimulation and decrease in sedation). In addition, an isolated mild decrease in digit vigilance accuracy occurred at 165 min post-dose after the combination. The co-administration of SMO.IR and alcohol was safe and well-tolerated. Conclusion SMO.IR and alcohol have distinct adverse effect profiles. The objective effects of SMO.IR are much less marked than those of alcohol. No deleterious interaction was observed. PMID:25782469
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Evaluation of Semi-supervised Learning for Classification of Protein Crystallization Imagery
Sigdel, Madhav; Dinç, İmren; Dinç, Semih; Sigdel, Madhu S.; Pusey, Marc L.; Aygün, Ramazan S.
2015-01-01
In this paper, we investigate the performance of two wrapper methods for semi-supervised learning algorithms for classification of protein crystallization images with limited labeled images. Firstly, we evaluate the performance of semi-supervised approach using self-training with naïve Bayesian (NB) and sequential minimum optimization (SMO) as the base classifiers. The confidence values returned by these classifiers are used to select high confident predictions to be used for self-training. Secondly, we analyze the performance of Yet Another Two Stage Idea (YATSI) semi-supervised learning using NB, SMO, multilayer perceptron (MLP), J48 and random forest (RF) classifiers. These results are compared with the basic supervised learning using the same training sets. We perform our experiments on a dataset consisting of 2250 protein crystallization images for different proportions of training and test data. Our results indicate that NB and SMO using both self-training and YATSI semi-supervised approaches improve accuracies with respect to supervised learning. On the other hand, MLP, J48 and RF perform better using basic supervised learning. Overall, random forest classifier yields the best accuracy with supervised learning for our dataset. PMID:25914518
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Yang, Bin; Hird, Alexander W; Russell, Daniel John; Fauber, Benjamin P; Dakin, Les A; Zheng, Xiaolan; Su, Qibin; Godin, Robert; Brassil, Patrick; Devereaux, Erik; Janetka, James W
2012-07-15
Cell-based subset screening of compounds using a Gli transcription factor reporter cell assay and shh stimulated cell differentiation assay identified a series of bisamide compounds as hedgehog pathway inhibitors with good potency. Using a ligand-based optimization strategy, heteroaryl groups were utilized as conformationally restricted amide isosteres replacing one of the amides which significantly increased their potency against SMO and the hedgehog pathway while decreasing activity against p38α kinase. We report herein the identification of advanced lead compounds such as imidazole 11c and 11f encompassing good p38α selectivity, low nanomolar potency in both cell assays, excellent physiochemical properties and in vivo pharmacokinetics. Copyright © 2012 Elsevier Ltd. All rights reserved.
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Improving 130nm node patterning using inverse lithography techniques for an analog process
NASA Astrophysics Data System (ADS)
Duan, Can; Jessen, Scott; Ziger, David; Watanabe, Mizuki; Prins, Steve; Ho, Chi-Chien; Shu, Jing
2018-03-01
Developing a new lithographic process routinely involves usage of lithographic toolsets and much engineering time to perform data analysis. Process transfers between fabs occur quite often. One of the key assumptions made is that lithographic settings are equivalent from one fab to another and that the transfer is fluid. In some cases, that is far from the truth. Differences in tools can change the proximity effect seen in low k1 imaging processes. If you use model based optical proximity correction (MBOPC), then a model built in one fab will not work under the same conditions at another fab. This results in many wafers being patterned to try and match a baseline response. Even if matching is achieved, there is no guarantee that optimal lithographic responses are met. In this paper, we discuss the approach used to transfer and develop new lithographic processes and define MBOPC builds for the new lithographic process in Fab B which was transferred from a similar lithographic process in Fab A. By using PROLITHTM simulations to match OPC models for each level, minimal downtime in wafer processing was observed. Source Mask Optimization (SMO) was also used to optimize lithographic processes using novel inverse lithography techniques (ILT) to simultaneously optimize mask bias, depth of focus (DOF), exposure latitude (EL) and mask error enhancement factor (MEEF) for critical designs for each level.
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Hydrogen Gas Sensors Based on Semiconductor Oxide Nanostructures
Gu, Haoshuang; Wang, Zhao; Hu, Yongming
2012-01-01
Recently, the hydrogen gas sensing properties of semiconductor oxide (SMO) nanostructures have been widely investigated. In this article, we provide a comprehensive review of the research progress in the last five years concerning hydrogen gas sensors based on SMO thin film and one-dimensional (1D) nanostructures. The hydrogen sensing mechanism of SMO nanostructures and some critical issues are discussed. Doping, noble metal-decoration, heterojunctions and size reduction have been investigated and proved to be effective methods for improving the sensing performance of SMO thin films and 1D nanostructures. The effect on the hydrogen response of SMO thin films and 1D nanostructures of grain boundary and crystal orientation, as well as the sensor architecture, including electrode size and nanojunctions have also been studied. Finally, we also discuss some challenges for the future applications of SMO nanostructured hydrogen sensors. PMID:22778599
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Gupta, Deepak Prasad; Hwang, Jae-Won; Cho, Eui-Sic; Kim, Won; Song, Chang Ho; Chai, Ok Hee
2017-01-01
Sonic Hedgehog (Shh) signaling plays a major role in and is essential for regulation, patterning, and proliferation during renal development. Smoothened (Smo) plays a pivot role in transducing the Shh-glioma-associated oncogene Kruppel family member. However, the cellular and molecular mechanism underlying the role of sustained Smo activation in postnatal kidney development is still not clearly understood. Using a conditional knockin mouse model that expresses a constitutively activated form of Smo (SmoM2) upon Homeobox-B7-mediated recombination (Hoxb7-Cre), the effects of Shh signaling were determined in postnatal kidney development. SmoM2;Hoxb7-Cre mutant mice showed growth retardation with a reduction of body weight. Constitutive activation of Smo in the renal collecting ducts caused renal hypoplasia, hydronephrosis, and hydroureter. The parenchymal area and glomerular numbers were reduced, but the glomerular density was increased in SmoM2;Hoxb7-Cre mutant mice. The expression of Patched 1, the receptor of Shh and a downstream target gene of the Shh signaling pathway, was highly restricted and it was upregulated in the inner medullary collecting ducts of the kidney. The proliferative cells in the mesenchyme and collecting ducts were decreased in SmoM2;Hoxb7-Cre mutant mice. This study showed for the first time that sustained Smo inhibits postnatal kidney development by suppressing the proliferation of the mesenchyme and medullary collecting ducts in mice. © 2017 S. Karger AG, Basel.
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Gruber, Wolfgang; Hutzinger, Martin; Elmer, Dominik Patrick; Parigger, Thomas; Sternberg, Christina; Cegielkowski, Lukasz; Zaja, Mirko; Leban, Johann; Michel, Susanne; Hamm, Svetlana; Vitt, Daniel; Aberger, Fritz
2016-01-01
A wide range of human malignancies displays aberrant activation of Hedgehog (HH)/GLI signaling, including cancers of the skin, brain, gastrointestinal tract and hematopoietic system. Targeting oncogenic HH/GLI signaling with small molecule inhibitors of the essential pathway effector Smoothened (SMO) has shown remarkable therapeutic effects in patients with advanced and metastatic basal cell carcinoma. However, acquired and de novo resistance to SMO inhibitors poses severe limitations to the use of SMO antagonists and urgently calls for the identification of novel targets and compounds. Here we report on the identification of the Dual-Specificity-Tyrosine-Phosphorylation-Regulated Kinase 1B (DYRK1B) as critical positive regulator of HH/GLI signaling downstream of SMO. Genetic and chemical inhibition of DYRK1B in human and mouse cancer cells resulted in marked repression of HH signaling and GLI1 expression, respectively. Importantly, DYRK1B inhibition profoundly impaired GLI1 expression in both SMO-inhibitor sensitive and resistant settings. We further introduce a novel small molecule DYRK1B inhibitor, DYRKi, with suitable pharmacologic properties to impair SMO-dependent and SMO-independent oncogenic GLI activity. The results support the use of DYRK1B antagonists for the treatment of HH/GLI-associated cancers where SMO inhibitors fail to demonstrate therapeutic efficacy. PMID:26784250
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NASA Astrophysics Data System (ADS)
Crouse, Michael; Liebmann, Lars; Plachecki, Vince; Salama, Mohamed; Chen, Yulu; Saulnier, Nicole; Dunn, Derren; Matthew, Itty; Hsu, Stephen; Gronlund, Keith; Goodwin, Francis
2017-03-01
The initial readiness of EUV patterning was demonstrated in 2016 with IBM Alliance's 7nm device technology. The focus has now shifted to driving the 'effective' k1 factor and enabling the second generation of EUV patterning. Thus, Design Technology Co-optimization (DTCO) has become a critical part of technology enablement as scaling has become more challenging and the industry pushes the limits of EUV lithography. The working partnership between the design teams and the process development teams typically involves an iterative approach to evaluate the manufacturability of proposed designs, subsequent modifications to those designs and finally a design manual for the technology. While this approach has served the industry well for many generations, the challenges at the Beyond 7nm node require a more efficient approach. In this work, we describe the use of "Design Intent" lithographic layout optimization where we remove the iterative component of DTCO and replace it with an optimization that achieves both a "patterning friendly" design and minimizes the well-known EUV stochastic effects. Solved together, this "design intent" approach can more quickly achieve superior lithographic results while still meeting the original device's functional specifications. Specifically, in this work we will demonstrate "design intent" optimization for critical BEOL layers using design tolerance bands to guide the source mask co-optimization. The design tolerance bands can be either supplied as part of the original design or derived from some basic rules. Additionally, the EUV stochastic behavior is mitigated by enhancing the image log slope (ILS) for specific key features as part of the overall optimization. We will show the benefit of the "design intent approach" on both bidirectional and unidirectional 28nm min pitch standard logic layouts and compare the more typical iterative SMO approach. Thus demonstrating the benefit of allowing the design to float within the specified range. Lastly, we discuss how the evolution of this approach could lead to layout optimization based entirely on some minimal set of functional requirements and process constraints.
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Inhibition of polyamine and spermine oxidases by polyamine analogues.
Bianchi, Marzia; Polticelli, Fabio; Ascenzi, Paolo; Botta, Maurizio; Federico, Rodolfo; Mariottini, Paolo; Cona, Alessandra
2006-03-01
Polyamine oxidase (PAO) and spermine oxidase (SMO) are involved in the catabolism of polyamines--basic regulators of cell growth and proliferation. The discovery of selective inhibitors of PAO and SMO represents an important tool in studying the involvement of these enzymes in polyamine homeostasis and a starting point for the development of novel antineoplastic drugs. Here, a comparative study on murine PAO (mPAO) and SMO (mSMO) inhibition by the polyamine analogues 1,8-diaminooctane, 1,12-diaminododecane, N-prenylagmatine (G3), guazatine and N,N1-bis(2,3-butadienyl)-1,4-butanediamine (MDL72527) is reported. Interestingly, 1,12-Diaminododecane and G3 behave as specific inhibitors of mPAO, values of K(i) for mPAO inhibition being lower than those for mSMO inactivation by several orders of magnitude. The analysis of molecular models of mPAO and mSMO indicates a significant reduction of the hydrophobic pocket located in maize PAO (MPAO) at the wider catalytic tunnel opening. This observation provides a rationale to explain the lower affinity displayed by G3, guazatine and MDL72527 for mPAO and mSMO as compared to MPAO. The different behaviour displayed by 1,12-diaminododecane towards mPAO and mSMO reveals the occurrence of basic differences in the ligand binding mode of the two enzymes, the first enzyme interacting mainly with substrate secondary amino groups and the second one with substrate primary amino groups. Thus, the data reported here provide the basis for the development of novel and selective inhibitors able to discriminate between mammalian SMO and PAO activities.
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Grzelak, Candice Alexandra; Martelotto, Luciano Gastón; Sigglekow, Nicholas David; Patkunanathan, Bramilla; Ajami, Katerina; Calabro, Sarah Ruth; Dwyer, Benjamin James; Tirnitz-Parker, Janina Elke Eleonore; Watkins, D Neil; Warner, Fiona Jane; Shackel, Nicholas Adam; McCaughan, Geoffrey William
2014-01-01
In vertebrates, canonical Hedgehog (Hh) pathway activation requires Smoothened (SMO) translocation to the primary cilium (Pc), followed by a GLI-mediated transcriptional response. In addition, a similar gene regulation occurs in response to growth factors/cytokines, although independently of SMO signalling. The Hh pathway plays a critical role in liver fibrosis/regeneration, however, the mechanism of activation in chronic liver injury is poorly understood. This study aimed to characterise Hh pathway activation upon thioacetamide (TAA)-induced chronic liver injury in vivo by defining Hh-responsive cells, namely cells harbouring Pc and Pc-localised SMO. C57BL/6 mice (wild-type or Ptc1(+/-)) were TAA-treated. Liver injury and Hh ligand/pathway mRNA and protein expression were assessed in vivo. SMO/GLI manipulation and SMO-dependent/independent activation of GLI-mediated transcriptional response in Pc-positive (Pc(+)) cells were studied in vitro. In vivo, Hh activation was progressively induced following TAA. At the epithelial-mesenchymal interface, injured hepatocytes produced Hh ligands. Progenitors, myofibroblasts, leukocytes and hepatocytes were GLI2(+). Pc(+) cells increased following TAA, but only EpCAM(+)/GLI2(+) progenitors were Pc(+)/SMO(+). In vitro, SMO knockdown/hGli3-R overexpression reduced proliferation/viability in Pc(+) progenitors, whilst increased proliferation occurred with hGli1 overexpression. HGF induced GLI transcriptional activity independently of Pc/SMO. Ptc1(+/-) mice exhibited increased progenitor, myofibroblast and fibrosis responses. In chronic liver injury, Pc(+) progenitors receive Hh ligand signals and process it through Pc/SMO-dependent activation of GLI-mediated transcriptional response. Pc/SMO-independent GLI activation likely occurs in Pc(-)/GLI2(+) cells. Increased fibrosis in Hh gain-of-function mice likely occurs by primary progenitor expansion/proliferation and secondary fibrotic myofibroblast expansion, in close contact with progenitors. Copyright © 2013 European Association for the Study of the Liver. All rights reserved.
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Amendola, Giorgio; Di Maio, Danilo; La Pietra, Valeria; Cosconati, Sandro
2016-09-01
SMO receptor is one of the main components of the Hedgehog biochemical pathway. In the last decades compelling body of evidence demonstrated that this receptor is a pertinent target for the treatment of various types of solid tumors. Recently, the X-ray determination of the three-dimensional structure of SMO in complex with different antagonists opened up the way for the structure-based design of new antagonists for this receptor that could possibly overcome the limitations connected with the induction of acquired tumor resistance. Herein, taking advantage of three different docking software (namely Glide, PLANTS, and Vina) and of the available SMO structures we set up a retrospective virtual screening (VS) protocol. A database, made up by known SMO antagonists and compounds with no alleged activity against the receptor was created and screened against the different SMO structures. To evaluate the performance of the ranking in VS calculations different statistical metrics (EF, AUAC and BEDROC) were employed allowing to identify the best performing VS docking protocol. Results of these studies will serve as a platform for the application of structure-based VS against the pharmaceutically relevant SMO receptor. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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2004-01-01
The oxidation of polyamines induced by antitumour polyamine analogues has been associated with tumour response to specific agents. The human spermine oxidase, SMO(PAOh1), is one enzyme that may play a direct role in the cellular response to the antitumour polyamine analogues. In the present study, the induction of SMO(PAOh1) enzyme activity by CPENSpm [N1-ethyl-N11-(cyclopropyl)methyl-4,8,diazaundecane] is demonstrated to be a result of newly synthesized mRNA and protein. Inhibition of new RNA synthesis by actinomycin D inhibits both the appearance of SMO(PAOh1) mRNA and enzyme activity. Similarly, inhibition of newly synthesized protein with cycloheximide prevents analogue-induced enzyme activity. Half-life determinations indicate that stabilization of SMO(PAOh1) protein does not play a significant role in analogue-induced activity. However, half-life experiments using actinomycin D indicate that CPENSpm treatment not only increases mRNA expression, but also leads to a significant increase in mRNA half-life (17.1 and 8.8 h for CPENSpm-treated cells and control respectively). Using reporter constructs encompassing the SMO(PAOh1) promoter region, a 30–90% increase in transcription is observed after exposure to CPENSpm. The present results are consistent with the hypothesis that analogue-induced expression of SMO(PAOh1) is a result of increased transcription and stabilization of SMO(PAOh1) mRNA, leading to increased protein production and enzyme activity. These data indicate that the major level of control of SMO(PAOh1) expression in response to polyamine analogues exposure is at the level of mRNA. PMID:15496143
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Chaturvedi, Rupesh; de Sablet, Thibaut; Peek, Richard M.; Wilson, Keith T.
2012-01-01
We have recently reported that Helicobacter pylori strains expressing the virulence factor cytotoxin-associated gene A (CagA) stimulate increased levels of spermine oxidase (SMO) in gastric epithelial cells, while cagA– strains did not. SMO catabolizes the polyamine spermine and produces H2O2 that results in both apoptosis and DNA damage. Exogenous overexpression of CagA confirmed these findings, and knockdown or inhibition of SMO blocked CagA-mediated apoptosis and DNA damage. The strong association of SMO, apoptosis, and DNA damage was also demonstrated in humans infected with cagA+, but not cagA– strains. In infected gerbils and mice, DNA damage was CagA-dependent and only present in epithelial cells that expressed SMO. We also discovered SMOhigh gastric epithelial cells from infected animals with dysplasia that are resistant to apoptosis despite high levels of DNA damage. Inhibition of polyamine synthesis or SMO could abrogate the development of this cell population that may represent precursors for neoplastic transformation. PMID:22555547
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Petralia, Ronald S.; Schwartz, Catherine M.; Wang, Ya-Xian; Mattson, Mark P.; Yao, Pamela J.
2011-01-01
Cumulative evidence suggests that, aside from patterning the embryonic neural tube, Sonic hedgehog (Shh) signaling plays important roles in the mature nervous system. In this study, we investigate the expression and localization of the Shh signaling receptors, Patched (Ptch) and Smoothened (Smo), in the hippocampal neurons of young and mature rats. Reverse transcriptase-polymerase chain reaction and immunoblotting analyses show that the expression of Ptch and Smo remains at a moderate level in young postnatal and adult brains. By using immunofluorescence light microscopy and immunoelectron microscopy, we examine the spatial distribution of Ptch and Smo within the hippocampal neurons. In young developing neurons, Ptch and Smo are present in the processes and are clustered at their growth cones. In mature neurons, Ptch and Smo are concentrated in dendrites, spines, and postsynaptic sites. Synaptic Ptch and Smo often co-exist with unusual structures—synaptic spinules and autophagosomes. Our results reveal the anatomical organization of the Shh receptors within both the young and the mature hippocampal neurons. PMID:21618238
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CoSMoS Unravels Mysteries of Transcription Initiation
Gourse, Richard L.; Landick, Robert
2013-01-01
Using a fluorescence method called colocalization single-molecule spectroscopy (CoSMoS), Friedman and Gelles dissect the kinetics of transcription initiation at a bacterial promoter. Ultimately, CoSMoS could greatly aid the study of the effects of DNA sequence and transcription factors on both prokaryotic and eukaryotic promoters. PMID:22341438
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Changes in ankle joint motion after Supramalleolar osteotomy: a cadaveric model.
Kim, Hak Jun; Yeo, Eui Dong; Rhyu, Im Joo; Lee, Soon-Hyuck; Lee, Yeon Soo; Lee, Young Koo
2017-09-09
Malalignment of the ankle joint has been found after trauma, by neurological disorders, genetic predisposition and other unidentified factors, and results in asymmetrical joint loading. For a medial open wedge supramalleolar osteotomy(SMO), there are some debates as to whether concurrent fibular osteotomy should be performed. We assessed the changes in motion of ankle joint and plantar pressure after supramalleolar osteotomy without fibular osteotomy. Ten lower leg specimens below the knee were prepared from fresh-frozen human cadavers. They were harvested from five males (10 ankles)whose average age was 70 years. We assessed the motion of ankle joint as well as plantar pressure for SS(supra-syndesmotic) SMO and IS(intra-syndesmotic) SMO. After the osteotomy, each specimen was subjected to axial compression from 20 N preload to 350 N representing half-body weight. For the measurement of the motion of ankle joint, the changes in gap and point, angles in ankle joint were measured. The plantar pressure were also recorded using TekScan sensors. The changes in the various gap, point, and angles movements on SS-SMO and IS-SMO showed no statistically significant differences between the two groups. Regarding the shift of plantar center of force (COF) were noted in the anterolateral direction, but not statistically significant. SS-SMO and IS-SMO with intact fibula showed similar biomechanical effect on the ankle joint. We propose that IS-SMO should be considered carefully for the treatment of osteoarthrosis when fibular osteotomy is not performed because lateral cortex fracture was less likely using the intrasyndesmosis plane because of soft tissue support.
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Petralia, Ronald S; Schwartz, Catherine M; Wang, Ya-Xian; Mattson, Mark P; Yao, Pamela J
2011-12-15
Cumulative evidence suggests that, aside from patterning the embryonic neural tube, Sonic hedgehog (Shh) signaling plays important roles in the mature nervous system. In this study, we investigate the expression and localization of the Shh signaling receptors, Patched (Ptch) and Smoothened (Smo), in the hippocampal neurons of young and mature rats. Reverse transcriptase-polymerase chain reaction and immunoblotting analyses show that the expression of Ptch and Smo remains at a moderate level in young postnatal and adult brains. By using immunofluorescence light microscopy and immunoelectron microscopy, we examine the spatial distribution of Ptch and Smo within the hippocampal neurons. In young developing neurons, Ptch and Smo are present in the processes and are clustered at their growth cones. In mature neurons, Ptch and Smo are concentrated in dendrites, spines, and postsynaptic sites. Synaptic Ptch and Smo often co-exist with unusual structures-synaptic spinules and autophagosomes. Our results reveal the anatomical organization of the Shh receptors within both the young and the mature hippocampal neurons. Copyright © 2011 Wiley-Liss, Inc.
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Zhu, Shu Yun; Dong, Ying; Tu, Jie; Zhou, Yue; Zhou, Xing Hua; Xu, Bin
2014-01-01
Background: Silybum marianum has been used as herbal medicine for the treatment of liver disease, liver cirrhosis, and to prevent liver cancer in Europe and Asia since ancient times. Silybum marianum oil (SMO), a by-product of silymarin production, is rich in essential fatty acids, phospholipids, sterols, and vitamin E. However, it has not been very good development and use. Objective: In the present study, we used olive oil as a control to investigate the antioxidant and anti-aging effect of SMO in D-galactose (D-gal)-induced aging mice. Materials and Methods: D-gal was injected intraperitoneally (500 mg/kg body weight daily) for 7 weeks while SMO was simultaneously administered orally. The triglycerides (TRIG) and cholesterol (CHOL) levels were estimated in the serum. Superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), total antioxidant capacity (T-AOC), monoamine oxidase (MAO), malondialdehyde (MDA), caspase-3, and Bcl-2 were determined in the liver and brain. The activities of Na+-K+-adenosine triphosphatase (ATPase), Ca2+-Mg2+-ATPase, membrane potential (ΔΨm), and membrane fluidity of the liver mitochondrial were estimated. Results: SMO decreased levels of TRIG and CHOL in aging mice. SMO administration elevated the activities of SOD, GSH-Px, and T-AOC, which are suppressed by aging. The levels of MAO and MDA in the liver and brain were reduced by SMO administration in aging mice. Enzyme linked immunosorbent assay showed that SMO significantly decreased the concentration of caspase-3 and improved the activity of Bcl-2 in the liver and brain of aging mice. Furthermore, SMO significantly attenuated the D-gal induced liver mitochondrial dysfunction by improving the activities of Na+-K+-ATPase, Ca2+-Mg2+-ATPase, membrane potential (ΔΨm), and membrane fluidity. Conclusion: These results indicate that SMO effectively attenuated oxidative damage and improved apoptosis related factors as well as liver mitochondrial dysfunction in aging mice. PMID:24914315
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Tavladoraki, Paraskevi; Cervelli, Manuela; Antonangeli, Fabrizio; Minervini, Giovanni; Stano, Pasquale; Federico, Rodolfo; Mariottini, Paolo; Polticelli, Fabio
2011-04-01
Spermine oxidase (SMO) and acetylpolyamine oxidase (APAO) are FAD-dependent enzymes that are involved in the highly regulated pathways of polyamine biosynthesis and degradation. Polyamine content is strictly related to cell growth, and dysfunctions in polyamine metabolism have been linked with cancer. Specific inhibitors of SMO and APAO would allow analyzing the precise role of these enzymes in polyamine metabolism and related pathologies. However, none of the available polyamine oxidase inhibitors displays the desired characteristics of selective affinity and specificity. In addition, repeated efforts to obtain structural details at the atomic level on these two enzymes have all failed. In the present study, in an effort to better understand structure-function relationships, SMO enzyme-substrate complex has been probed through a combination of molecular modeling, site-directed mutagenesis and biochemical studies. Results obtained indicate that SMO binds spermine in a similar conformation as that observed in the yeast polyamine oxidase FMS1-spermine complex and demonstrate a major role for residues His82 and Lys367 in substrate binding and catalysis. In addition, the SMO enzyme-substrate complex highlights the presence of an active site pocket with highly polar characteristics, which may explain the different substrate specificity of SMO with respect to APAO and provide the basis for the design of specific inhibitors for SMO and APAO.
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CoSMoS unravels mysteries of transcription initiation.
Gourse, Richard L; Landick, Robert
2012-02-17
Using a fluorescence method called colocalization single-molecule spectroscopy (CoSMoS), Friedman and Gelles dissect the kinetics of transcription initiation at a bacterial promoter. Ultimately, CoSMoS could greatly aid the study of the effects of DNA sequence and transcription factors on both prokaryotic and eukaryotic promoters. Copyright © 2012 Elsevier Inc. All rights reserved.
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Chaturvedi, Rupesh; Asim, Mohammad; Barry, Daniel P; Frye, Jeanetta W; Casero, Robert A; Wilson, Keith T
2014-03-01
The gastric pathogen Helicobacter pylori causes peptic ulcer disease and gastric cancer. We have reported that in H. pylori-activated macrophages, nitric oxide (NO) derived from inducible NO synthase (iNOS) can kill the bacterium, iNOS protein expression is dependent on uptake of its substrate L-arginine (L-Arg), the polyamine spermine can inhibit iNOS translation by inhibiting L-Arg uptake, and inhibition of polyamine synthesis enhances NO-mediated bacterial killing. Because spermine oxidase (SMO), which back-converts spermine to spermidine, is induced in macrophages by H. pylori, we determined its role in iNOS-dependent host defense. SMO shRNA knockdown in RAW 264.7 murine macrophages resulted in a marked decrease in H. pylori-stimulated iNOS protein, but not mRNA expression, and a 90% reduction in NO levels; NO production was also inhibited in primary murine peritoneal macrophages with SMO knockdown. There was an increase in spermine levels after H. pylori stimulation that rapidly decreased, while SMO knockdown caused a greater increase in spermine that was sustained. With SMO knockdown, L-Arg uptake and killing of H. pylori by macrophages was prevented. The overexpression of SMO by transfection of an expression plasmid prevented the H. pylori-stimulated increase in spermine levels, and led to increased L-Arg uptake, iNOS protein expression and NO production, and H. pylori killing. In two human monocytic cell lines, U937 and THP-1, overexpression of SMO caused a significant enhancement of NO production with H. pylori stimulation. By depleting spermine, SMO can abrogate the inhibitory effect of polyamines on innate immune responses to H. pylori by enhancing antimicrobial NO production.
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Murray-Stewart, Tracy; Wang, Yanlin; Goodwin, Andrew; Hacker, Amy; Meeker, Alan; Casero, Robert A.
2013-01-01
The recent discovery of the direct oxidation of spermine via spermine oxidase (SMO) as a mechanism through which specific antitumor polyamine analogues exert their cytotoxic effects has fueled interest in the study of the polyamine catabolic pathway. A major byproduct of spermine oxidation is H2O2, a source of toxic reactive oxygen species. Recent targeted small interfering RNA studies have confirmed that SMO-produced reactive oxygen species are directly responsible for oxidative stress capable of inducing apoptosis and potentially mutagenic DNA damage. In the present study, we describe a second catalytically active splice variant protein of the human spermine oxidase gene, designated SMO5, which exhibits substrate specificities and affinities comparable to those of the originally identified human spermine oxidase-1, SMO/PAOh1, and, as such, is an additional source of H2O2. Importantly, overexpression of either of these SMO isoforms in NCI-H157 human non-small cell lung carcinoma cells resulted in significant localization of SMO protein in the nucleus, as determined by confocal microscopy. Furthermore, cell lines overexpressing either SMO/PAOh1 or SMO5 demonstrated increased spermine oxidation in the nucleus, with accompanying alterations in individual nuclear polyamine concentrations. This increased oxidation of spermine in the nucleus therefore increases the production of highly reactive H2O2 in close proximity to DNA, as well as decreases nuclear spermine levels, thus altering the protective roles of spermine in free radical scavenging and DNA shielding, and resulting in an overall increased potential for oxidative DNA damage in these cells. The results of these studies therefore have considerable significance both with respect to targeting polyamine oxidation as an antineoplastic strategy, and in regard to the potential role of spermine oxidase in inflammation-induced carcinogenesis. PMID:18422650
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Automated annotation of functional imaging experiments via multi-label classification
Turner, Matthew D.; Chakrabarti, Chayan; Jones, Thomas B.; Xu, Jiawei F.; Fox, Peter T.; Luger, George F.; Laird, Angela R.; Turner, Jessica A.
2013-01-01
Identifying the experimental methods in human neuroimaging papers is important for grouping meaningfully similar experiments for meta-analyses. Currently, this can only be done by human readers. We present the performance of common machine learning (text mining) methods applied to the problem of automatically classifying or labeling this literature. Labeling terms are from the Cognitive Paradigm Ontology (CogPO), the text corpora are abstracts of published functional neuroimaging papers, and the methods use the performance of a human expert as training data. We aim to replicate the expert's annotation of multiple labels per abstract identifying the experimental stimuli, cognitive paradigms, response types, and other relevant dimensions of the experiments. We use several standard machine learning methods: naive Bayes (NB), k-nearest neighbor, and support vector machines (specifically SMO or sequential minimal optimization). Exact match performance ranged from only 15% in the worst cases to 78% in the best cases. NB methods combined with binary relevance transformations performed strongly and were robust to overfitting. This collection of results demonstrates what can be achieved with off-the-shelf software components and little to no pre-processing of raw text. PMID:24409112
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Multivariate Time Series Forecasting of Crude Palm Oil Price Using Machine Learning Techniques
NASA Astrophysics Data System (ADS)
Kanchymalay, Kasturi; Salim, N.; Sukprasert, Anupong; Krishnan, Ramesh; Raba'ah Hashim, Ummi
2017-08-01
The aim of this paper was to study the correlation between crude palm oil (CPO) price, selected vegetable oil prices (such as soybean oil, coconut oil, and olive oil, rapeseed oil and sunflower oil), crude oil and the monthly exchange rate. Comparative analysis was then performed on CPO price forecasting results using the machine learning techniques. Monthly CPO prices, selected vegetable oil prices, crude oil prices and monthly exchange rate data from January 1987 to February 2017 were utilized. Preliminary analysis showed a positive and high correlation between the CPO price and soy bean oil price and also between CPO price and crude oil price. Experiments were conducted using multi-layer perception, support vector regression and Holt Winter exponential smoothing techniques. The results were assessed by using criteria of root mean square error (RMSE), means absolute error (MAE), means absolute percentage error (MAPE) and Direction of accuracy (DA). Among these three techniques, support vector regression(SVR) with Sequential minimal optimization (SMO) algorithm showed relatively better results compared to multi-layer perceptron and Holt Winters exponential smoothing method.
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ERIC Educational Resources Information Center
Abou-Warda, Sherein H.
2014-01-01
Higher education institutions are increasingly concerned about accreditation. Although sustainable market orientation (SMO) bears on academic accreditation, to date, no study has developed a valid scale of SMO or assessed its influence on accreditation. The purpose of this paper is to construct and validate an SMO scale that was developed in…
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Joint optimization of source, mask, and pupil in optical lithography
NASA Astrophysics Data System (ADS)
Li, Jia; Lam, Edmund Y.
2014-03-01
Mask topography effects need to be taken into consideration for more advanced resolution enhancement techniques in optical lithography. However, rigorous 3D mask model achieves high accuracy at a large computational cost. This work develops a combined source, mask and pupil optimization (SMPO) approach by taking advantage of the fact that pupil phase manipulation is capable of partially compensating for mask topography effects. We first design the pupil wavefront function by incorporating primary and secondary spherical aberration through the coefficients of the Zernike polynomials, and achieve optimal source-mask pair under the condition of aberrated pupil. Evaluations against conventional source mask optimization (SMO) without incorporating pupil aberrations show that SMPO provides improved performance in terms of pattern fidelity and process window sizes.
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Braun, Joerg E; Serebrov, Victor
2017-01-01
Recent development of single-molecule techniques to study pre-mRNA splicing has provided insights into the dynamic nature of the spliceosome. Colocalization single-molecule spectroscopy (CoSMoS) allows following spliceosome assembly in real time at single-molecule resolution in the full complexity of cellular extracts. A detailed protocol of CoSMoS has been published previously (Anderson and Hoskins, Methods Mol Biol 1126:217-241, 2014). Here, we provide an update on the technical advances since the first CoSMoS studies including slide surface treatment, data processing, and representation. We describe various labeling strategies to generate RNA reporters with multiple dyes (or other moieties) at specific locations.
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Methanol Adsorption and Reaction on Samaria Thin Films on Pt(111).
Jhang, Jin-Hao; Schaefer, Andreas; Zielasek, Volkmar; Weaver, Jason F; Bäumer, Marcus
2015-09-17
We investigated the adsorption and reaction of methanol on continuous and discontinuous films of samarium oxide (SmO x ) grown on Pt(111) in ultrahigh vacuum. The methanol decomposition was studied by temperature programmed desorption (TPD) and infrared reflection absorption spectroscopy (IRRAS), while structural changes of the oxide surface were monitored by low-energy electron diffraction (LEED). Methanol dehydrogenates to adsorbed methoxy species on both the continuous and discontinuous SmO x films, eventually leading to the desorption of CO and H₂ which desorbs at temperatures in the range 400-600 K. Small quantities of CO₂ are also detected mainly on as-prepared Sm₂O₃ thin films, but the production of CO₂ is limited during repeated TPD runs. The discontinuous film exhibits the highest reactivity compared to the continuous film and the Pt(111) substrate. The reactivity of methanol on reduced and reoxidized films was also investigated, revealing how SmO x structures influence the chemical behavior. Over repeated TPD experiments, a SmO x structural/chemical equilibrium condition is found which can be approached either from oxidized or reduced films. We also observed hydrogen absence in TPD which indicates that hydrogen is stored either in SmO x films or as OH groups on the SmO x surfaces.
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Dissipation of sulfamethoxazole in pasture soils as affected by soil and environmental factors.
Srinivasan, Prakash; Sarmah, Ajit K
2014-05-01
The dissipation of sulfamethoxazole (SMO) antibiotic in three different soils was investigated through laboratory incubation studies. The experiments were conducted under different incubation conditions such as initial chemical concentration, soil depth, temperature, and with sterilisation. The results indicate that SMO dissipated rapidly in New Zealand pasture soils, and the 50% dissipation times (DT50) in Hamilton, Te Kowhai and Horotiu soils under non-sterile conditions were 9.24, 4.3 and 13.33 days respectively. During the incubation period for each sampling event the soil dehydrogenase activity (DHA) and the variation in microbial community were monitored thorough phospholipid fatty acid extraction analysis (PLFA). The DHA data correlated well with the dissipation rate constants of SMO antibiotic, an increase in the DHA activity resulted in faster antibiotic dissipation. The PLFA analysis was indicative of higher bacterial presence as compared to fungal community, highlighting the type of microbial community responsible for dissipation. The results indicate that with increasing soil depth, SMO dissipation in soil was slower (except for Horotiu) while with increase in temperature the antibiotic loss was faster, and was noticeable in all the soils. Both the degree of biological activity and the temperature of the soil influenced overall SMO dissipation. SMO is not likely to persist more than 5-6 months in all three soils suggesting that natural biodegradation may be sufficient for the removal of these contaminants from the soil. Its dissipation in sterile soils indicated abiotic factors such as strong sorption onto soil components to play a role in the dissipation of SMO. Copyright © 2014 Elsevier B.V. All rights reserved.
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Digging a hole under Hedgehog: downstream inhibition as an emerging anticancer strategy.
Di Magno, Laura; Coni, Sonia; Di Marcotullio, Lucia; Canettieri, Gianluca
2015-08-01
Hedgehog signaling is a key regulator of development and stem cell fate and its aberrant activation is a leading cause of a number of tumors. Activating germline or somatic mutations of genes encoding Hh pathway components are found in Basal Cell Carcinoma (BCC) and Medulloblastoma (MB). Ligand-dependent Hedgehog hyperactivation, due to autocrine or paracrine mechanisms, is also observed in a large number of malignancies of the breast, colon, skin, bladder, pancreas and other tissues. The key tumorigenic role of Hedgehog has prompted effort aimed at identifying inhibitors of this signaling. To date, only the antagonists of the membrane transducer Smo have been approved for therapy or are under clinical trials in patients with BCC and MB linked to Ptch or Smo mutations. Despite the good initial response, patients treated with Smo antagonists have eventually developed resistance due to the occurrence of compensating mechanisms. Furthermore, Smo antagonists are not effective in tumors where the Hedgehog hyperactivation is due to mutations of pathway components downstream of Smo, or in case of non-canonical, Smo-independent activation of the Gli transcription factors. For all these reasons, the research of Hh inhibitors acting downstream of Smo is becoming an area of intensive investigation. In this review we illustrate the progresses made in the identification of effective Hedgehog inhibitors and their application in cancer, with a special emphasis on the newly identified downstream inhibitors. We describe in detail the Gli inhibitors and illustrate their mode of action and applications in experimental and/or clinical settings. Copyright © 2015 Elsevier B.V. All rights reserved.
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CoSMoMVPA: Multi-Modal Multivariate Pattern Analysis of Neuroimaging Data in Matlab/GNU Octave.
Oosterhof, Nikolaas N; Connolly, Andrew C; Haxby, James V
2016-01-01
Recent years have seen an increase in the popularity of multivariate pattern (MVP) analysis of functional magnetic resonance (fMRI) data, and, to a much lesser extent, magneto- and electro-encephalography (M/EEG) data. We present CoSMoMVPA, a lightweight MVPA (MVP analysis) toolbox implemented in the intersection of the Matlab and GNU Octave languages, that treats both fMRI and M/EEG data as first-class citizens. CoSMoMVPA supports all state-of-the-art MVP analysis techniques, including searchlight analyses, classification, correlations, representational similarity analysis, and the time generalization method. These can be used to address both data-driven and hypothesis-driven questions about neural organization and representations, both within and across: space, time, frequency bands, neuroimaging modalities, individuals, and species. It uses a uniform data representation of fMRI data in the volume or on the surface, and of M/EEG data at the sensor and source level. Through various external toolboxes, it directly supports reading and writing a variety of fMRI and M/EEG neuroimaging formats, and, where applicable, can convert between them. As a result, it can be integrated readily in existing pipelines and used with existing preprocessed datasets. CoSMoMVPA overloads the traditional volumetric searchlight concept to support neighborhoods for M/EEG and surface-based fMRI data, which supports localization of multivariate effects of interest across space, time, and frequency dimensions. CoSMoMVPA also provides a generalized approach to multiple comparison correction across these dimensions using Threshold-Free Cluster Enhancement with state-of-the-art clustering and permutation techniques. CoSMoMVPA is highly modular and uses abstractions to provide a uniform interface for a variety of MVP measures. Typical analyses require a few lines of code, making it accessible to beginner users. At the same time, expert programmers can easily extend its functionality. CoSMoMVPA comes with extensive documentation, including a variety of runnable demonstration scripts and analysis exercises (with example data and solutions). It uses best software engineering practices including version control, distributed development, an automated test suite, and continuous integration testing. It can be used with the proprietary Matlab and the free GNU Octave software, and it complies with open source distribution platforms such as NeuroDebian. CoSMoMVPA is Free/Open Source Software under the permissive MIT license. Website: http://cosmomvpa.org Source code: https://github.com/CoSMoMVPA/CoSMoMVPA.
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CoSMoMVPA: Multi-Modal Multivariate Pattern Analysis of Neuroimaging Data in Matlab/GNU Octave
Oosterhof, Nikolaas N.; Connolly, Andrew C.; Haxby, James V.
2016-01-01
Recent years have seen an increase in the popularity of multivariate pattern (MVP) analysis of functional magnetic resonance (fMRI) data, and, to a much lesser extent, magneto- and electro-encephalography (M/EEG) data. We present CoSMoMVPA, a lightweight MVPA (MVP analysis) toolbox implemented in the intersection of the Matlab and GNU Octave languages, that treats both fMRI and M/EEG data as first-class citizens. CoSMoMVPA supports all state-of-the-art MVP analysis techniques, including searchlight analyses, classification, correlations, representational similarity analysis, and the time generalization method. These can be used to address both data-driven and hypothesis-driven questions about neural organization and representations, both within and across: space, time, frequency bands, neuroimaging modalities, individuals, and species. It uses a uniform data representation of fMRI data in the volume or on the surface, and of M/EEG data at the sensor and source level. Through various external toolboxes, it directly supports reading and writing a variety of fMRI and M/EEG neuroimaging formats, and, where applicable, can convert between them. As a result, it can be integrated readily in existing pipelines and used with existing preprocessed datasets. CoSMoMVPA overloads the traditional volumetric searchlight concept to support neighborhoods for M/EEG and surface-based fMRI data, which supports localization of multivariate effects of interest across space, time, and frequency dimensions. CoSMoMVPA also provides a generalized approach to multiple comparison correction across these dimensions using Threshold-Free Cluster Enhancement with state-of-the-art clustering and permutation techniques. CoSMoMVPA is highly modular and uses abstractions to provide a uniform interface for a variety of MVP measures. Typical analyses require a few lines of code, making it accessible to beginner users. At the same time, expert programmers can easily extend its functionality. CoSMoMVPA comes with extensive documentation, including a variety of runnable demonstration scripts and analysis exercises (with example data and solutions). It uses best software engineering practices including version control, distributed development, an automated test suite, and continuous integration testing. It can be used with the proprietary Matlab and the free GNU Octave software, and it complies with open source distribution platforms such as NeuroDebian. CoSMoMVPA is Free/Open Source Software under the permissive MIT license. Website: http://cosmomvpa.org Source code: https://github.com/CoSMoMVPA/CoSMoMVPA PMID:27499741
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Oria, Prisca A; Alaii, Jane; Ayugi, Margaret; Takken, Willem; Leeuwis, Cees
2015-08-01
To investigate community adherence to recommended behaviours for proper deployment of solar-powered mosquito trapping systems (SMoTS) after 3- to 10-week use. Solar-powered mosquito trapping system, which also provided power for room lighting and charging mobile phones, were installed in houses in Rusinga Island, western Kenya. We used a structured checklist for observations and a semi-structured questionnaire for interviews in 24 homesteads. We also analysed the subject of 224 community calls to the project team for technical maintenance of SMoTS. Most respondents cared for SMoTS by fencing, emptying and cleaning the trap. Our observations revealed that most traps were fenced, clean and in good working condition. A significantly higher proportion of community calls was lighting-related. Lighting was the main reason respondents liked SMoTS because it reduced or eliminated expenditure on kerosene. However, some respondents observed they no longer heard sounds of mosquitoes inside their houses. All respondents reportedly slept under insecticide-treated nets (ITNs) before receiving SMoTS. After receiving SMoTS, most respondents reportedly continued to use ITNs citing that the project advised them to do so. Some beach residents stopped using ITNs because they no longer heard mosquitoes or due to heat discomfort caused by lights. Electricity-related incentives played a greater role in encouraging adherence to recommended behaviours for proper deployment of SMoTS than the potential health benefits in the early stages of the intervention. Although energy-related financial incentives may play a role, they are insufficient to ensure adherence to health advice, even in the short term. Ongoing community engagement and research monitors and addresses adherence to recommended behaviours including continuation of current malaria control strategies. © 2015 John Wiley & Sons Ltd.
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NASA Astrophysics Data System (ADS)
Peng, Qiu-he; Chou, Chih-kang
2001-04-01
The fact that magnetic monopoles may catalyze nucleon decay (the Rubakov-Callan [RC] effect) as predicated by the grand unified theory of particle physics is invoked as the energy source of quasars and active galactic nuclei. Recent study of this model revealed that the radius of the supermassive object (SMO) located at the Galactic center is much larger than its Schwarzschild radius. We propose that this SMOs could be the source of high-energy gamma-ray radiation, although the emitted radiation may be mainly concentrated in the infrared. The surface temperature of the SMO at the Galactic center is taken as 121 K, inferred from the observed maximum of the flux spectrum of Sgr A* at the near infrared (1×1013 Hz); the radius of the SMO is about 8.1×1015 cm or 1.1×104RS (RS is the Schwarzschild radius). The mass of the SMO is derived from the observed total luminosity of Sgr A* (1×1037 ergs s-1) as 2.5×106 Msolar. Strong gamma-ray radiation with energy higher than 0.5 MeV may be emitted from the SMO. The flux of positrons emitted from the SMO is estimated to be 6.5×1042e+ s-1. The content parameter of magnetic monopoles ξ≡[(Nm/NB)/1.9×10- 25](<σβ>/10-27) also may be deduced from observations to be 230. Taking the cross section of the RC effect as 1×10-27 cm2, the strength of the radial magnetic field at the surface of the SMO is estimated to be 20-100 G. Our model also can predict the production of extreme ultra-high-energy cosmic rays.
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Zhang, Ya-Ran; Gui, Lin-Sheng; Li, Yao-Kun; Jiang, Bi-Jie; Wang, Hong-Cheng; Zhang, Ying-Ying; Zan, Lin-Sen
2015-07-27
Smoothened (Smo)-mediated Hedgehog (Hh) signaling pathway governs the patterning, morphogenesis and growth of many different regions within animal body plans. This study evaluated the effects of genetic variations of the bovine SMO gene on economically important body size traits in Chinese Qinchuan cattle. Altogether, eight single nucleotide polymorphisms (SNPs: 1-8) were identified and genotyped via direct sequencing covering most of the coding region and 3'UTR of the bovine SMO gene. Both the p.698Ser.>Ser. synonymous mutation resulted from SNP1 and the p.700Ser.>Pro. non-synonymous mutation caused by SNP2 mapped to the intracellular C-terminal tail of bovine Smo protein; the other six SNPs were non-coding variants located in the 3'UTR. The linkage disequilibrium was analyzed, and five haplotypes were discovered in 520 Qinchuan cattle. Association analyses showed that SNP2, SNP3/5, SNP4 and SNP6/7 were significantly associated with some body size traits (p < 0.05) except SNP1/8 (p > 0.05). Meanwhile, cattle with wild-type combined haplotype Hap1/Hap1 had significantly (p < 0.05) greater body length than those with Hap2/Hap2. Our results indicate that variations in the SMO gene could affect body size traits of Qinchuan cattle, and the wild-type haplotype Hap1 together with the wild-type alleles of these detected SNPs in the SMO gene could be used to breed cattle with superior body size traits. Therefore, our results could be helpful for marker-assisted selection in beef cattle breeding programs.
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Zhang, Ya-Ran; Gui, Lin-Sheng; Li, Yao-Kun; Jiang, Bi-Jie; Wang, Hong-Cheng; Zhang, Ying-Ying; Zan, Lin-Sen
2015-01-01
Smoothened (Smo)-mediated Hedgehog (Hh) signaling pathway governs the patterning, morphogenesis and growth of many different regions within animal body plans. This study evaluated the effects of genetic variations of the bovine SMO gene on economically important body size traits in Chinese Qinchuan cattle. Altogether, eight single nucleotide polymorphisms (SNPs: 1–8) were identified and genotyped via direct sequencing covering most of the coding region and 3ʹUTR of the bovine SMO gene. Both the p.698Ser.>Ser. synonymous mutation resulted from SNP1 and the p.700Ser.>Pro. non-synonymous mutation caused by SNP2 mapped to the intracellular C-terminal tail of bovine Smo protein; the other six SNPs were non-coding variants located in the 3ʹUTR. The linkage disequilibrium was analyzed, and five haplotypes were discovered in 520 Qinchuan cattle. Association analyses showed that SNP2, SNP3/5, SNP4 and SNP6/7 were significantly associated with some body size traits (p < 0.05) except SNP1/8 (p > 0.05). Meanwhile, cattle with wild-type combined haplotype Hap1/Hap1 had significantly (p < 0.05) greater body length than those with Hap2/Hap2. Our results indicate that variations in the SMO gene could affect body size traits of Qinchuan cattle, and the wild-type haplotype Hap1 together with the wild-type alleles of these detected SNPs in the SMO gene could be used to breed cattle with superior body size traits. Therefore, our results could be helpful for marker-assisted selection in beef cattle breeding programs. PMID:26225956
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Hedgehog signaling contributes to basic fibroblast growth factor-regulated fibroblast migration
DOE Office of Scientific and Technical Information (OSTI.GOV)
Zhu, Zhong Xin; Sun, Cong Cong; Wenzhou People's Hospital, Wenzhou, Zhejiang
Fibroblast migration is a central process in skin wound healing, which requires the coordination of several types of growth factors. bFGF, a well-known fibroblast growth factor (FGF), is able to accelerate fibroblast migration; however, the underlying mechanism of bFGF regulation fibroblast migration remains unclear. Through the RNA-seq analysis, we had identified that the hedgehog (Hh) canonical pathway genes including Smoothened (Smo) and Gli1, were regulated by bFGF. Further analysis revealed that activation of the Hh pathway via up-regulation of Smo promoted fibroblast migration, invasion, and skin wound healing, but which significantly reduced by GANT61, a selective antagonist of Gli1/Gli2. Westernmore » blot analyses and siRNA transfection assays demonstrated that Smo acted upstream of phosphoinositide 3-kinase (PI3K)-c-Jun N-terminal kinase (JNK)-β-catenin to promote cell migration. Moreover, RNA-seq and qRT-PCR analyses revealed that Hh pathway genes including Smo and Gli1 were under control of β-catenin, suggesting that β-catenin turn feedback activates Hh signaling. Taken together, our analyses identified a new bFGF-regulating mechanism by which Hh signaling regulates human fibroblast migration, and the data presented here opens a new avenue for the wound healing therapy. - Highlights: • bFGF regulates Hedgehog (Hh) signaling in fibroblasts. • The Smo and Gli two master regulators of Hh signaling positively regulate fibroblast migration. • Smo facilitates β-catenin nuclear translocation via activation PI3K/JNK/GSK3β. • β-catenin positively regulates fibroblast cell migration and the expression of Hh signaling genes including Smo and Gli.« less
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A Human Activity Recognition System Based on Dynamic Clustering of Skeleton Data.
Manzi, Alessandro; Dario, Paolo; Cavallo, Filippo
2017-05-11
Human activity recognition is an important area in computer vision, with its wide range of applications including ambient assisted living. In this paper, an activity recognition system based on skeleton data extracted from a depth camera is presented. The system makes use of machine learning techniques to classify the actions that are described with a set of a few basic postures. The training phase creates several models related to the number of clustered postures by means of a multiclass Support Vector Machine (SVM), trained with Sequential Minimal Optimization (SMO). The classification phase adopts the X-means algorithm to find the optimal number of clusters dynamically. The contribution of the paper is twofold. The first aim is to perform activity recognition employing features based on a small number of informative postures, extracted independently from each activity instance; secondly, it aims to assess the minimum number of frames needed for an adequate classification. The system is evaluated on two publicly available datasets, the Cornell Activity Dataset (CAD-60) and the Telecommunication Systems Team (TST) Fall detection dataset. The number of clusters needed to model each instance ranges from two to four elements. The proposed approach reaches excellent performances using only about 4 s of input data (~100 frames) and outperforms the state of the art when it uses approximately 500 frames on the CAD-60 dataset. The results are promising for the test in real context.
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GENERAL VIEW, LOOKING SOUTHEAST, OF STANDARDIZING MAGNETIC OBSERVATORY (SMO) WHICH ...
GENERAL VIEW, LOOKING SOUTHEAST, OF STANDARDIZING MAGNETIC OBSERVATORY (SMO) WHICH IS TO THE RIGHT. THE BUILDING TO THE LEFT IS 'STATION 'A'', ALSO A NON-MAGNETIC STRUCTURE, ONCE USED FOR COMPARISONS OF MAGNETIC INSTRUMENTS WITH THE SMO. THE BUILDING IN THE CENTER CONTAINED A SEARCH-LIGHT USED IN CONJUNCTION WITH MEASUREMENTS OF THE EARTH'S ATMOSPHERE. - Carnegie Institution of Washington, Department of Terrestrial Magnetism, Standardizing Magnetic Observatory, 5241 Broad Branch Drive Northwest, Washington, District of Columbia, DC
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Dynamics of a bistable Miura-origami structure
NASA Astrophysics Data System (ADS)
Fang, Hongbin; Li, Suyi; Ji, Huimin; Wang, K. W.
2017-05-01
Origami-inspired structures and materials have shown extraordinary properties and performances originating from the intricate geometries of folding. However, current state of the art studies have mostly focused on static and quasistatic characteristics. This research performs a comprehensive experimental and analytical study on the dynamics of origami folding through investigating a stacked Miura-Ori (SMO) structure with intrinsic bistability. We fabricate and experimentally investigated a bistable SMO prototype with rigid facets and flexible crease lines. Under harmonic base excitation, the SMO exhibits both intrawell and interwell oscillations. Spectrum analyses reveal that the dominant nonlinearities of SMO are quadratic and cubic, which generate rich dynamics including subharmonic and chaotic oscillations. The identified nonlinearities indicate that a third-order polynomial can be employed to approximate the measured force-displacement relationship. Such an approximation is validated via numerical study by qualitatively reproducing the phenomena observed in the experiments. The dynamic characteristics of the bistable SMO resemble those of a Helmholtz-Duffing oscillator (HDO); this suggests the possibility of applying the established tools and insights of HDO to predict origami dynamics. We also show that the bistability of SMO can be programmed within a large design space via tailoring the crease stiffness and initial stress-free configurations. The results of this research offer a wealth of fundamental insights into the dynamics of origami folding, and provide a solid foundation for developing foldable and deployable structures and materials with embedded dynamic functionalities.
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Ma, Weiwei; Wu, Mengnan; Zhou, Siyan; Tao, Ye; Xie, Zuolei; Zhong, Yi
2018-05-20
Emerging evidence suggests that neuro-inflammation begins early and drives the pathogenesis of Alzheimer's disease (AD), and anti-inflammatory therapies are under clinical development. However, several anti-inflammatory compounds failed to improve memory in clinical trials, indicating that reducing inflammation alone might not be enough. On the other hand, neuro-inflammation is implicated in a number of mental disorders which share the same therapeutic targets. Based on these observations, we screened a batch of genes related with mental disorder and neuro-inflammation in a classical olfactory conditioning in an amyloid beta (Aβ) overexpression fly model. A Smoothened (SMO) mutant was identified as a genetic modifier of Aβ toxicity in 3-min memory and downregulation of SMO rescued Aβ-induced 3-min and 1-h memory deficiency. Also, Aβ activated innate inflammatory response in fly by increasing the expression of antimicrobial peptides, which were alleviated by downregulating SMO. Furthermore, pharmaceutical administration of a SMO antagonist LDE rescued Aβ-induced upregulation of SMO in astrocytes of mouse hippocampus, improved memory in Morris water maze (MWM), and reduced expression of astrocyte secreting pro-inflammatory factors IL-1β, TNFα and the microglia marker IBA-1 in an APP/PS1 transgenic mouse model. Our study suggests that SMO is an important conserved modulator of Aβ toxicity in both fly and mouse models of AD. Copyright © 2018. Published by Elsevier Ltd.
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Zhu, Gefei A; Li, Angela S; Chang, Anne Lynn S
2014-08-01
Basal cell carcinomas (BCCs) in patients with Gorlin syndrome have been reported to be extremely sensitive to Smoothened (SMO) inhibitors, a novel targeted therapy against the Hedgehog pathway, because of characteristic mutations in these patients. A few cases of disease refractory to oral therapy with SMO inhibitors have been reported in patients with Gorlin syndrome and nonmetastatic BCCs, but refractory disease in distantly metastatic tumors has not been documented in this high-risk group. A man with Gorlin syndrome and innumerable cutaneous BCCs presented with biopsy-proven BCC in his lungs. After SMO inhibitor therapy, almost all of his cutaneous tumors shrank, but his lung metastases did not. These lung metastases remained refractory to treatment despite institution of a second SMO inhibitor. We report a case of Gorlin syndrome in a patient with metastatic BCC refractory to SMO inhibitors. Furthermore, clinical responses in this patient's cutaneous tumors did not parallel the responses in the distant site. However, serial imaging after diagnosis of metastatic disease can be critical to monitor for response to therapy.
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Magnetic and electronic properties of SrMnO3 thin films
NASA Astrophysics Data System (ADS)
Mandal, Arup Kumar; Panchal, Gyanendra; Choudhary, R. J.; Phase, D. M.
2018-05-01
Single phase hexagonal bulk SrMnO3 (SMO) was prepared by solid state route and it was used for depositing thin films by pulsed laser deposition (PLD) technique on single crystalline (100) oriented SrTiO3 (STO) substrate. X-ray diffraction shows that the thin film is deposited in cubic SrMnO3 phase. From X-ray absorption at the Mn L edge we observed the mixed valency of Mn (Mn3+& Mn4+) due to strain induced by the lattice mismatching between SMO and STO. Due to this mixed valency of Mn ion in SMO film, the ferromagnetic nature is observed at lower temperature because of double exchange. After post annealing with very low oxygen partial pressure, magnetic and electronic property of SMO films are effectively modified.
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NASA Technical Reports Server (NTRS)
Ellerby, Gwenn E. C.; Lee, Stuart M. C.; Paunescu, Lelia Adelina; Pereira, Chelsea; Smith, Charles P.; Soller, Babs R.
2011-01-01
The effect of leg dominance on the symmetry of the biomechanics during cycling remains uncertain -- asymmetries have been observed in kinematics and kinetics, while symmetries were found in muscle activation. No studies have yet investigated the symmetry of muscle metabolism during cycling. Near-infrared spectroscopy (NIRS) provides a non-invasive method to investigate the metabolic responses of specific muscles during cycling. PURPOSE: To determine whether there was an effect of leg dominance on thigh muscle oxygen saturation (SmO2) during incrementally loaded submaximal cycling using NIRS. METHODS: Eight right leg dominant, untrained subjects (5 men, 3 women; 31+/-2 yrs; 168.6+/-1.0 cm; 67.2+/-1.8 kg, mean +/- SE) volunteered to participate. Spectra were collected bilaterally from the vastus lateralis (VL) during supine rest and cycling. SmO2 was calculated using previously published methods. Subjects pedaled at 65 rpm while resistance to pedaling was increased in 0.5 kp increments from 0.5 kp every 3 min until the subject reached 80% of age-predicted maximal heart rate. SmO2 was averaged over 3 min for each completed stage. A two-way ANOVA was performed to test for leg differences. A priori contrasts were used to compare work levels to rest. RESULTS: VL SmO2 was not different between the dominant and non-dominant legs at rest and during exercise (p=0.57). How SmO2 changed with workload was also not different between legs (p=0.32). SmO2 at 0.5 kp (60.3+/-4.0, p=0.12) and 1.0 kp (59.5+/-4.0, p=0.10) was not different from rest (69.1+/-4.0). SmO2 at 1.5 kp (55.4 4.0, p=0.02), 2.0 kp (55.7+/-5.0, p=0.04), and 2.5 kp (43.4+/-7.9, p=0.01) was significantly lower than rest. CONCLUSION: VL SmO2 during cycling is not different between dominant and non-dominant legs and decreases with moderate workload in untrained cyclists. Assuming blood flow is directed equally to both legs, similar levels of oxygen extraction (as indicated by SmO2) suggests the metabolic load of cycling is not different between legs. This is in agreement with a recent study demonstrating symmetrical increase of muscle activation of the VL during cycling. Leg dominance did not influence VL SmO2 during submaximal cycling, but may have an effect at higher loads or during other forms of exercise, such as walking and running.
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Antineoplastic Efficacy of Novel Polyamine Analogues in Human Breast Cancer
2005-06-01
Davidson, N.E., and Casero, R.A.. Spermine oxidase SMO(PAOh1), not N1-acetylpolyamine oxidase (PAO) is the primary source of cytotoxic H2O2 in polyamine... spermine oxidase (PAOh1/SMO) mRNA and activity by a polyamine analogue in human breast cancer cell lines. The fourth Era of Hope meeting for the...SMO/PAOh1 Spermine Oxidase DFMO α-difluoromethylornithine BENSpm N1, N11-bis(ethyl)norspermine CHEMSpm N1-(cycloheptylmethyl)-N11-ethyl- 4,8
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Sequence Based Prediction of Antioxidant Proteins Using a Classifier Selection Strategy
Zhang, Lina; Zhang, Chengjin; Gao, Rui; Yang, Runtao; Song, Qing
2016-01-01
Antioxidant proteins perform significant functions in maintaining oxidation/antioxidation balance and have potential therapies for some diseases. Accurate identification of antioxidant proteins could contribute to revealing physiological processes of oxidation/antioxidation balance and developing novel antioxidation-based drugs. In this study, an ensemble method is presented to predict antioxidant proteins with hybrid features, incorporating SSI (Secondary Structure Information), PSSM (Position Specific Scoring Matrix), RSA (Relative Solvent Accessibility), and CTD (Composition, Transition, Distribution). The prediction results of the ensemble predictor are determined by an average of prediction results of multiple base classifiers. Based on a classifier selection strategy, we obtain an optimal ensemble classifier composed of RF (Random Forest), SMO (Sequential Minimal Optimization), NNA (Nearest Neighbor Algorithm), and J48 with an accuracy of 0.925. A Relief combined with IFS (Incremental Feature Selection) method is adopted to obtain optimal features from hybrid features. With the optimal features, the ensemble method achieves improved performance with a sensitivity of 0.95, a specificity of 0.93, an accuracy of 0.94, and an MCC (Matthew’s Correlation Coefficient) of 0.880, far better than the existing method. To evaluate the prediction performance objectively, the proposed method is compared with existing methods on the same independent testing dataset. Encouragingly, our method performs better than previous studies. In addition, our method achieves more balanced performance with a sensitivity of 0.878 and a specificity of 0.860. These results suggest that the proposed ensemble method can be a potential candidate for antioxidant protein prediction. For public access, we develop a user-friendly web server for antioxidant protein identification that is freely accessible at http://antioxidant.weka.cc. PMID:27662651
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Acyl-CoA-Binding Protein ACBP1 Modulates Sterol Synthesis during Embryogenesis1[OPEN
Hsiao, An-Shan; Xue, Yan
2017-01-01
Fatty acids (FAs) and sterols are primary metabolites that exert interrelated functions as structural and signaling lipids. Despite their common syntheses from acetyl-coenzyme A, homeostatic cross talk remains enigmatic. Six Arabidopsis (Arabidopsis thaliana) acyl-coenzyme A-binding proteins (ACBPs) are involved in FA metabolism. ACBP1 interacts with PHOSPHOLIPASE Dα1 and regulates phospholipid composition. Here, its specific role in the negative modulation of sterol synthesis during embryogenesis is reported. ACBP1, likely in a liganded state, interacts with STEROL C4-METHYL OXIDASE1-1 (SMO1-1), a rate-limiting enzyme in the sterol pathway. Proembryo abortion in the double mutant indicated that the ACBP1-SMO1-1 interaction is synthetic lethal, corroborating with their strong promoter activities in developing ovules. Gas chromatography-mass spectrometry revealed quantitative and compositional changes in FAs and sterols upon overexpression or mutation of ACBP1 and/or SMO1-1. Aberrant levels of these metabolites may account for the downstream defect in lipid signaling. GLABRA2 (GL2), encoding a phospholipid/sterol-binding homeodomain transcription factor, was up-regulated in developing seeds of acbp1, smo1-1, and ACBP1+/−smo1-1 in comparison with the wild type. Consistent with the corresponding transcriptional alteration of GL2 targets, high-oil, low-mucilage phenotypes of gl2 were phenocopied in ACBP1+/−smo1-1. Thus, ACBP1 appears to modulate the metabolism of two important lipid classes (FAs and sterols) influencing cellular signaling. PMID:28500265
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NASA Technical Reports Server (NTRS)
Crucian, Brian; Stowe, Raymond; Mehta, Satish; Uchakin, Peter; Nehlsen-Cannarella, Sandra; Morukov, Boris; Pierson, Duane; Sams, Clarence
2007-01-01
There is ample evidence to suggest that space flight leads to immune system dysregulation. This may be a result of microgravity, confinement, physiological stress, radiation, environment or other mission-associated factors. The clinical risk from prolonged immune dysregulation during space flight are not yet determined, but may include increased incidence of infection, allergy, hypersensitivity, hematological malignancy or altered wound healing. Each of the clinical events resulting from immune dysfunction has the potential to impact mission critical objectives during exploration-class missions. To date, precious little in-flight immune data has been generated to assess this phenomenon. The majority of recent flight immune studies have been post-flight assessments, which may not accurately reflect the in-flight condition. There are no procedures currently in place to monitor immune function or its effect on crew health. The objective of this Supplemental Medical Objective (SMO) is to develop and validate an immune monitoring strategy consistent with operational flight requirements and constraints. This SMO will assess the clinical risks resulting from the adverse effects of space flight on the human immune system and will validate a flight-compatible immune monitoring strategy. Characterization of the clinical risk and the development of a monitoring strategy are necessary prerequisite activities prior to validating countermeasures. This study will determine, to the best level allowed by current technology, the in-flight status of crewmembers immune system. Pre-flight, in-flight and post-flight assessments of immune status, immune function, viral reactivation and physiological stress will be performed. The in-flight samples will allow a distinction between legitimate in-flight alterations and the physiological stresses of landing and readaptation which are believed to alter landing day assessments. The overall status of the immune system during flight (activation, deficiency, dysregulation) and the response of the immune system to specific latent virus reactivation (known to occur during space flight) will be thoroughly assessed. Following completion of the SMO the data will be evaluated to determine the optimal set of assays for routine monitoring of crewmember immune system function, should the clinical risk warrant such monitoring.
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S V, Mahesh Kumar; R, Gunasundari
2018-06-02
Eye disease is a major health problem among the elderly people. Cataract and corneal arcus are the major abnormalities that exist in the anterior segment eye region of aged people. Hence, computer-aided diagnosis of anterior segment eye abnormalities will be helpful for mass screening and grading in ophthalmology. In this paper, we propose a multiclass computer-aided diagnosis (CAD) system using visible wavelength (VW) eye images to diagnose anterior segment eye abnormalities. In the proposed method, the input VW eye images are pre-processed for specular reflection removal and the iris circle region is segmented using a circular Hough Transform (CHT)-based approach. The first-order statistical features and wavelet-based features are extracted from the segmented iris circle and used for classification. The Support Vector Machine (SVM) by Sequential Minimal Optimization (SMO) algorithm was used for the classification. In experiments, we used 228 VW eye images that belong to three different classes of anterior segment eye abnormalities. The proposed method achieved a predictive accuracy of 96.96% with 97% sensitivity and 99% specificity. The experimental results show that the proposed method has significant potential for use in clinical applications.
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Sprick, Justin D; Soller, Babs R; Rickards, Caroline A
2016-11-01
Muscle tissue oxygenation (SmO 2 ) can track central blood volume loss associated with hemorrhage. Traditional peripheral measurement sites (e.g., forearm) may not be practical due to excessive movement or injury (e.g., amputation). The aim of this study was to evaluate the efficacy of three novel anatomical sites for the assessment of SmO 2 under progressive central hypovolemia. 10 male volunteers were exposed to stepwise prone lower body negative pressure to decrease central blood volume, while SmO 2 was assessed at four sites-the traditional site of the flexor carpi ulnaris (ARM), and three novel sites not previously investigated during lower body negative pressure, the deltoid, latissimus dorsi, and trapezius. SmO 2 at the novel sites was compared to the ARM sensor and to stroke volume responses. A reduction in SmO 2 was detected by the ARM sensor at the first level of lower body negative pressure (-15 mmHg; P = 0.007), and at -30 (the deltoid), -45 (latissimus dorsi), and -60 mmHg lower body negative pressure (trapezius) at the novel sites (P ≤ 0.04). SmO 2 responses at all novel sites were correlated with responses at the ARM (R ≥ 0.89), and tracked the reduction in stroke volume (R ≥ 0.87); the latissimus dorsi site exhibited the strongest linear correlations (R ≥ 0.96). Of the novel sensor sites, the latissimus dorsi exhibited the strongest linear associations with SmO 2 at the ARM, and with reductions in central blood volume. These findings have important implications for detection of hemorrhage in austere environments (e.g., combat) when use of a peripheral sensor may not be ideal, and may facilitate incorporation of these sensors into uniforms. © 2016 by the Society for Experimental Biology and Medicine.
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Infrared spectra and density functional calculations for SMO2 molecules (M = Cr, Mo, W).
Wang, Xuefeng; Andrews, Lester
2009-08-06
Infrared absorptions of the matrix isolated SMO2 (M = Cr, Mo, W) molecules were observed following laser-ablated metal atom reactions with SO2 during condensation in solid argon and neon. The symmetric and antisymmetric M-O stretching mode assignments were confirmed by appropriate S18O2 and S(16,18)O2 isotopic shifts. The much weaker Cr-S stretching mode was identified through its 34S shift. Density functional (B3LYP and BPW91) calculations were performed to obtain molecular structures and to reproduce the infrared spectra. Computed pyramidal structures for the SMO2 molecules are very similar to those for the analogous trioxides and this functional group in [MO2S(bdt)]2- complexes. Additional weaker absorptions are assigned to the (SO2)(SMO2) adducts, which are stabilized by a four-membered ring.
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Ren, Jun-Jie; Liu, Yan-Cheng; Wang, Ning; Liu, Si-Yuan
2015-01-01
This paper proposes a sensorless speed control strategy for ship propulsion interior permanent magnet synchronous motor (IPMSM) based on a new sliding-mode observer (SMO). In the SMO the low-pass filter and the method of arc-tangent calculation of extended electromotive force (EMF) or phase-locked loop (PLL) technique are not used. The calculation of the rotor speed is deduced from the Lyapunov function stability analysis. In order to reduce system chattering, sigmoid functions with switching gains being adaptively updated by fuzzy logic systems are innovatively incorporated into the SMO. Finally, simulation results for a 4.088 MW ship propulsion IPMSM and experimental results from a 7.5 kW IPMSM drive are provided to verify the effectiveness of the proposed SMO method. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.
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Structure of the human smoothened receptor 7TM bound to an antitumor agent
Wang, Chong; Wu, Huixian; Katritch, Vsevolod; Han, Gye Won; Huang, Xi-Ping; Liu, Wei; Siu, Fai Yiu; Roth, Bryan L.; Cherezov, Vadim; Stevens, Raymond C.
2013-01-01
The smoothened (SMO) receptor, a key signal transducer in the Hedgehog (Hh) signaling pathway is both responsible for the maintenance of normal embryonic development and implicated in carcinogenesis. The SMO receptor is classified as a class Frizzled (class F) G protein-coupled receptor (GPCR), although the canonical Hh signaling pathway involves the transcription factor Gli and the sequence similarity with class A GPCRs is less than 10%. Here we report the crystal structure at 2.5 Å resolution of the transmembrane domain of the human SMO receptor bound to the small molecule antagonist LY2940680. Although the SMO receptor shares the seven transmembrane helical (7TM) fold, most conserved motifs for class A GPCRs are absent, and the structure reveals an unusually complex arrangement of long extracellular loops stabilized by four disulfide bonds. The ligand binds at the extracellular end of the 7TM bundle and forms extensive contacts with the loops. PMID:23636324
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Acyl-CoA-Binding Protein ACBP1 Modulates Sterol Synthesis during Embryogenesis.
Lung, Shiu-Cheung; Liao, Pan; Yeung, Edward C; Hsiao, An-Shan; Xue, Yan; Chye, Mee-Len
2017-07-01
Fatty acids (FAs) and sterols are primary metabolites that exert interrelated functions as structural and signaling lipids. Despite their common syntheses from acetyl-coenzyme A, homeostatic cross talk remains enigmatic. Six Arabidopsis ( Arabidopsis thaliana ) acyl-coenzyme A-binding proteins (ACBPs) are involved in FA metabolism. ACBP1 interacts with PHOSPHOLIPASE Dα1 and regulates phospholipid composition. Here, its specific role in the negative modulation of sterol synthesis during embryogenesis is reported. ACBP1, likely in a liganded state, interacts with STEROL C4-METHYL OXIDASE1-1 (SMO1-1), a rate-limiting enzyme in the sterol pathway. Proembryo abortion in the double mutant indicated that the ACBP1-SMO1-1 interaction is synthetic lethal, corroborating with their strong promoter activities in developing ovules. Gas chromatography-mass spectrometry revealed quantitative and compositional changes in FAs and sterols upon overexpression or mutation of ACBP1 and/or SMO1-1 Aberrant levels of these metabolites may account for the downstream defect in lipid signaling. GLABRA2 ( GL2 ), encoding a phospholipid/sterol-binding homeodomain transcription factor, was up-regulated in developing seeds of acbp1 , smo1-1 , and ACBP1 +/- smo1-1 in comparison with the wild type. Consistent with the corresponding transcriptional alteration of GL2 targets, high-oil, low-mucilage phenotypes of gl2 were phenocopied in ACBP1 +/- smo1-1 Thus, ACBP1 appears to modulate the metabolism of two important lipid classes (FAs and sterols) influencing cellular signaling. © 2017 American Society of Plant Biologists. All Rights Reserved.
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Zhang, Y R; Li, Y K; Fu, C Z; Wang, J L; Wang, H B; Zan, L S
2014-10-07
Beef cattle breeding programs focus on improving important economic traits, including growth rates, and meat quantity and quality. Molecular marker-assisted selection based on genetic variation represents a potential method for breeding genetically improved livestock with better economic traits. Smoothened (SMO) protein is a signal transducer that contributes to the regulation of both osteogenesis and adipogenesis through the hedgehog pathway. In this study, we detected polymorphisms in the bovine SMO gene of Qinchuan cattle, and we analyzed their associations with body measurement traits (BMTs) and meat quality traits (MQTs). Using DNA sequencing and polymerase chain reaction-restriction fragment length polymorphism, 3 novel single nucleotide polymorphisms were identified in the SMO gene of 562 cattle: 1 G > C mutation on exon 9 (G21234C) and 2 C > T mutations on exon 11 (C22424T and C22481T). Association analysis showed that polymorphisms on both the G21234C and C22424T loci significantly affected certain BMTs and MQTs (P < 0.05 or P < 0.01), whereas those on the C22481T locus did not (P > 0.05). Therefore, the SMO gene could be used as a candidate gene to alter BMTs and MQTs in Qinchuan cattle or for marker-assisted selection to breed cattle with superior BMTs and MQTs.
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Regaining motor control in musician's dystonia by restoring sensorimotor organisation
Rosenkranz, Karin; Butler, Katherine; Williamon, Aaron; Rothwell, John C.
2010-01-01
Professional musicians are an excellent human model of long term effects of skilled motor training on the structure and function of the motor system. However, such effects are accompanied by an increased risk of developing motor abnormalities, in particular musician's dystonia. Previously we found that there was an expanded spatial integration of proprioceptive input into the hand area of motor cortex (sensorimotor organisation, SMO) in healthy musicians as tested with a transcranial magnetic stimulation (TMS) paradigm. In musician's dystonia, this expansion was even larger, resulting in a complete lack of somatotopic organisation. We hypothesised that the disordered motor control in musician's dystonia is a consequence of the disordered SMO. In the present paper we test this idea by giving pianists with musician's dystonia 15 min experience of a modified proprioceptive training task. This restored SMO towards that seen in healthy pianists. Crucially, motor control of the affected task improved significantly and objectively as measured with a MIDI piano, and the amount of behavioural improvement was significantly correlated to the degree of sensorimotor re-organisation. In healthy pianists and non-musicians, the SMO and motor performance remained essentially unchanged. These findings suggest a link between the differentiation of SMO in the hand motor cortex and the degree of motor control of intensively practiced tasks in highly skilled individuals. PMID:19923295
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Sorption of selected veterinary antibiotics onto dairy farming soils of contrasting nature.
Srinivasan, Prakash; Sarmah, Ajit K; Manley-Harris, Merilyn
2014-02-15
The sorption potential for three sulfonamides (SAs), sulfamethoxazole (SMO), sulfachloropyridazine (SCP) and sulfamethazine (SM) and a macrolide, tylosin tartrate (TT) was assessed on six New Zealand dairy farming soils of contrasting physico-chemical properties. Kinetics studies showed that the sorption was rapid in the first few hours of the contact time (0-2h for SA and 0-4h for TT) and thereafter apparent equilibrium was achieved. Batch sorption isotherm data revealed that the degree of isotherm linearity (N) for SCP and SM varied between 0.50 and 1.08 in the six soils. Isotherms of both TT and SMO were mostly non-linear with the degree of non-linearity for TT (N=0.38-0.71) being greater than for SMO (0.42-0.75) in all soils except Manawatu (TT) and Te Kowhai (SMO) where a linear pattern was observed. Concentration-dependent effective distribution coefficient (Kd(eff)) values for the SMO, SCP and SM antibiotics in the soils ranged from 0.85 to 16.35 L kg(-1), while that for TT was 1.6 to 1,042 L kg(-1). The sorption affinity for all soils followed an order: TT>SCP>SM>SMO. Remarkable high sorption for tylosin in Matawhero soil as compared to other soils was attributed to the presence of oxygen containing acidic polar functional groups as evident in the FT-IR spectra of the soil. Furthermore, it was hypothesised that sorption of TT onto soils was mostly driven by metal oxide-surface mediated transformations whereas for sulfonamides it was primarily due to hydrophobic interactions. Copyright © 2013 Elsevier B.V. All rights reserved.
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Douglas, Andrew E.; Heim, Jennifer A.; Shen, Feng; Almada, Luciana L.; Riobo, Natalia A.; Fernández-Zapico, Martin E.; Manning, David R.
2011-01-01
Smoothened (Smo) is a seven-transmembrane (7-TM) receptor that is essential to most actions of the Hedgehog family of morphogens. We found previously that Smo couples to members of the Gi family of heterotrimeric G proteins, which in some cases are integral although alone insufficient in the activation of Gli transcription factors through Hedgehog signaling. In response to a report that the G12/13 family is relevant to Hedgehog signaling as well, we re-evaluated the coupling of Smo to one member of this family, G13, and investigated the capacity of this and other G proteins to activate one or more of forms of Gli. We found no evidence that Smo couples directly to G13. We found nonetheless that Gα13 and to some extent Gαq and Gα12 are able to effect activation of Gli(s). This capacity is realized in some cells, e.g. C3H10T1/2, MC3T3, and pancreatic cancer cells, but not all cells. The mechanism employed is distinct from that achieved through canonical Hedgehog signaling, as the activation does not involve autocrine signaling or in any other way require active Smo and does not necessarily involve enhanced transcription of Gli1. The activation by Gα13 can be replicated through a Gq/G12/13-coupled receptor, CCKA, and is attenuated by inhibitors of p38 mitogen-activated protein kinase and Tec tyrosine kinases. We posit that G proteins, and perhaps G13 in particular, provide access to Gli that is independent of Smo and that they thus establish a basis for control of at least some forms of Gli-mediated transcription apart from Hedgehogs. PMID:21757753
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Ge, Xin; Lyu, Pengwei; Gu, Yuanting
Sonic hesgehog (Shh) signaling has been reported to play an essential role in cancer progression. The mechanism of Shh involved in breast cancer carcinogenesis remains unclear. The present study sought to explore whether Shh signaling could regulate the glycolytic metabolism in breast cancers. Overexpression of the smoothed (Smo) and Gli-1 was found in human primary breast cancers. The expressions of Shh and Gli-1 correlated significantly with tumor size and tumor stage. In vitro, human recombinant Shh (rShh) triggered Smo and Gli-1 expression, promoted glucose utilization and lactate production, and accelerated cell proliferation in MCF-7 and MDA-MB-231 cells. Notably, rShh did notmore » alter 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3) expression but augmented PFKFB3 phosphorylation on ser{sup 461}, along with elevated fructose-2,6-bisphosphate (F2,6BP) generation by MCF-7 and MDA-MB-231 cells. This effect could be dampened by Smo siRNA but not by Gli-1 siRNA. In addition, our data showed the upregulated expressions of MAPK by rShh and elevatory PFKFB3 phosphorylation by p38/MAPK activated kinase (MK2). In conclusion, our study characterized a novel role of Shh in promoting glycolysis and proliferation of breast cancer cells via PFKFB3 phosphorylation, which was mediated by Smo and p38/MK2. - Highlights: • Overexpression of Smo and Gli-1 was found in human primary breast cancers. • Shh promoted glucose utilization, lactate production, and cell proliferation. • Shh did not alter PFKFB3 expression but augmented PFKFB3 phosphorylation on ser461. • Shh acts on PFKFB3 phosphorylation via Smo and p38 MAPK/MK2.« less
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Ye, Lijuan; Xu, Haiyan; Zhang, Dingke
2014-07-01
Highlights: • Hexagonal phase of MoS{sub 2} nanosheets was synthesized by a facile hydrothermal method. • FE-SEM and TEM images show the sheets-like morphology of MoS{sub 2}. • Bilayer MoS{sub 2} can be grown under the optimized mole ratio of 2:1 of S:Mo at 180 °C for 50 h. • The MoS{sub 2} nanosheets possess high methyl orange adsorption capacity due to the large surface area. - Abstract: Molybdenum disulfide (MoS{sub 2}) nanosheets have received significant attention recently due to the potential applications for exciting physics and technology. Here we show that MoS{sub 2} nanosheets can be prepared by amore » facile hydrothermal method. The study of the properties of the MoS{sub 2} nanosheets prepared at different conditions suggests that the mole ratio of precursors and hydrothermal time significantly influences the purity, crystalline quality and thermal stability of MoS{sub 2}. X-ray diffraction, Raman spectra and transmission electron microscopy results indicate that bilayer MoS{sub 2} can be grown under an optimized mole ratio of 2:1 of S:Mo at 180 °C for 50 h. Moreover, such ultrathin nanosheets exhibit a prominent photoluminescence and possess high methyl orange adsorption capacity due to the large surface area, which can be potentially used in photodevice and photochemical catalyst.« less
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Optimization of a methamphetamine conjugate vaccine for antibody production in mice.
Stevens, Misty W; Gunnell, Melinda G; Tawney, Rachel; Owens, S Michael
2016-06-01
There are still no approved medications for treating patients who abuse methamphetamine. Active vaccines for treating abuse of nicotine and cocaine are in clinical studies, but have not proven effective seemingly due to inadequate anti-drug antibody production. The current studies aimed to optimize the composition, adjuvant and route of administration of a methamphetamine conjugate vaccine, ICKLH-SMO9, in mice with the goal of generating significantly higher antibody levels. A range of hapten epitope densities were compared, as were the adjuvants Alhydrogel and a new Toll-like receptor 4 (TLR4) agonist called GLA-SE. While methamphetamine hapten density did not strongly affect the antibody response, the adjuvant did. Glucopyranosyl lipid A in a stable oil-in-water emulsion (GLA-SE) produced much higher levels of antibody in response to immunization compared with Alhydrogel; immunization with GLA-SE also produced antibodies with higher affinities for methamphetamine. GLA-SE has been used in human studies of vaccines for influenza among others and like some other clinical TLR4 agonists, it is safe and elicits a strong immune response. GLA-SE adjuvanted vaccines are typically administered by intramuscular injection and this also proved effective in these mouse studies. Clinical studies of the ICKLH-SMO9 methamphetamine vaccine adjuvanted with GLA-SE have the potential for demonstrating efficacy by generating much higher levels of antibody than substance abuse vaccines that have unsuccessfully used aluminum-based adjuvants. Copyright © 2016 Elsevier B.V. All rights reserved.
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Decoding the phosphorylation code in Hedgehog signal transduction
Chen, Yongbin; Jiang, Jin
2013-01-01
Hedgehog (Hh) signaling plays pivotal roles in embryonic development and adult tissue homeostasis, and its deregulation leads to numerous human disorders including cancer. Binding of Hh to Patched (Ptc), a twelve-transmembrane protein, alleviates its inhibition of Smoothened (Smo), a seven-transmembrane protein related to G-protein-coupled receptors (GPCRs), leading to Smo phosphorylation and activation. Smo acts through intracellular signaling complexes to convert the latent transcription factor Cubitus interruptus (Ci)/Gli from a truncated repressor to a full-length activator, leading to derepression/activation of Hh target genes. Increasing evidence suggests that phosphorylation participates in almost every step in the signal relay from Smo to Ci/Gli, and that differential phosphorylation of several key pathway components may be crucial for translating the Hh morphogen gradient into graded pathway activities. In this review, we focus on the multifaceted roles that phosphorylation plays in Hh signal transduction, and discuss the conservation and difference between Drosophila and mammalian Hh signaling mechanisms. PMID:23337587
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Sonic hedgehog signaling regulates actin cytoskeleton via Tiam1-Rac1 cascade during spine formation.
Sasaki, Nobunari; Kurisu, Junko; Kengaku, Mineko
2010-12-01
The sonic hedgehog (Shh) pathway has essential roles in several processes during development of the vertebrate central nervous system (CNS). Here, we report that Shh regulates dendritic spine formation in hippocampal pyramidal neurons via a novel pathway that directly regulates the actin cytoskeleton. Shh signaling molecules Patched (Ptc) and Smoothened (Smo) are expressed in several types of postmitotic neurons, including cerebellar Purkinje cells and hippocampal pyramidal neurons. Knockdown of Smo induces dendritic spine formation in cultured hippocampal neurons independently of Gli-mediated transcriptional activity. Smo interacts with Tiam1, a guanine nucleotide exchange factor for Rac1, via its cytoplasmic C-terminal region. Inhibition of Tiam1 or Rac1 activity suppresses spine induction by Smo knockdown. Shh induces remodeling of the actin cytoskeleton independently of transcriptional activation in mouse embryonic fibroblasts. These findings demonstrate a novel Shh pathway that regulates the actin cytoskeleton via Tiam1-Rac1 activation. Copyright © 2010 Elsevier Inc. All rights reserved.
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Choe, Shawn; Bond, Christopher W; Harrington, Daniel A; Stupp, Samuel I; McVary, Kevin T; Podlasek, Carol A
2017-01-01
Erectile dysfunction (ED) has high impact on quality of life in prostatectomy, diabetic and aging patients. An underlying mechanism is cavernous nerve (CN) injury, which causes ED in up to 80% of prostatectomy patients. We examine how sonic hedgehog (SHH) treatment with innovative peptide amphiphile nanofiber hydrogels (PA), promotes CN regeneration after injury. SHH and its receptors patched (PTCH1) and smoothened (SMO) are localized in PG neurons and glia. SMO undergoes anterograde transport to signal to downstream targets. With crush injury, PG neurons degenerate and undergo apoptosis. SHH protein decreases, SMO localization changes to the neuronal cell surface, and anterograde transport stops. With SHH treatment SHH is taken up at the injury site and undergoes retrograde transport to PG neurons, allowing SMO transport to occur, and neurons remain intact. SHH treatment prevents neuronal degeneration, maintains neuronal, glial and downstream target signaling, and is significant as a regenerative therapy. Published by Elsevier Inc.
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Cholesterol activates the G-protein coupled receptor Smoothened to promote Hedgehog signaling
Luchetti, Giovanni; Sircar, Ria; Kong, Jennifer H; Nachtergaele, Sigrid; Sagner, Andreas; Byrne, Eamon FX; Covey, Douglas F; Siebold, Christian; Rohatgi, Rajat
2016-01-01
Cholesterol is necessary for the function of many G-protein coupled receptors (GPCRs). We find that cholesterol is not just necessary but also sufficient to activate signaling by the Hedgehog (Hh) pathway, a prominent cell-cell communication system in development. Cholesterol influences Hh signaling by directly activating Smoothened (SMO), an orphan GPCR that transmits the Hh signal across the membrane in all animals. Unlike many GPCRs, which are regulated by cholesterol through their heptahelical transmembrane domains, SMO is activated by cholesterol through its extracellular cysteine-rich domain (CRD). Residues shown to mediate cholesterol binding to the CRD in a recent structural analysis also dictate SMO activation, both in response to cholesterol and to native Hh ligands. Our results show that cholesterol can initiate signaling from the cell surface by engaging the extracellular domain of a GPCR and suggest that SMO activity may be regulated by local changes in cholesterol abundance or accessibility. DOI: http://dx.doi.org/10.7554/eLife.20304.001 PMID:27705744
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Reisner, Andrew T; Edla, Shwetha; Liu, Jianbo; Rubin, John T; Thorsen, Jill E; Kittell, Erin; Smith, Jason B; Yeh, Daniel D; Reifman, Jaques
2016-03-01
During initial assessment of trauma patients, vital signs do not identify all patients with life-threatening hemorrhage. We hypothesized that a novel vital sign, muscle oxygen saturation (SmO2 ), could provide independent diagnostic information beyond routine vital signs for identification of hemorrhaging patients who require packed red blood cell (RBC) transfusion. This was an observational study of adult trauma patients treated at a Level I trauma center. Study staff placed the CareGuide 1100 tissue oximeter (Reflectance Medical Inc., Westborough, MA), and we analyzed average values of SmO2 , systolic blood pressure (sBP), pulse pressure (PP), and heart rate (HR) during 10 minutes of early emergency department evaluation. We excluded subjects without a full set of vital signs during the observation interval. The study outcome was hemorrhagic injury and RBC transfusion ≥ 3 units in 24 hours (24-hr RBC ≥ 3). To test the hypothesis that SmO2 added independent information beyond routine vital signs, we developed one logistic regression model with HR, sBP, and PP and one with SmO2 in addition to HR, sBP, and PP and compared their areas under receiver operating characteristic curves (ROC AUCs) using DeLong's test. We enrolled 487 subjects; 23 received 24-hr RBC ≥ 3. Compared to the model without SmO2 , the regression model with SmO2 had a significantly increased ROC AUC for the prediction of ≥ 3 units of 24-hr RBC volume, 0.85 (95% confidence interval [CI], 0.75-0.91) versus 0.77 (95% CI, 0.66-0.86; p < 0.05 per DeLong's test). Results were similar for ROC AUCs predicting patients (n = 11) receiving 24-hr RBC ≥ 9. SmO2 significantly improved the diagnostic association between initial vital signs and hemorrhagic injury with blood transfusion. This parameter may enhance the early identification of patients who require blood products for life-threatening hemorrhage. © 2016 The Authors. Academic Emergency Medicine published by Wiley Periodicals, Inc. on behalf of Society for Academic Emergency Medicine.
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Max-margin weight learning for medical knowledge network.
Jiang, Jingchi; Xie, Jing; Zhao, Chao; Su, Jia; Guan, Yi; Yu, Qiubin
2018-03-01
The application of medical knowledge strongly affects the performance of intelligent diagnosis, and method of learning the weights of medical knowledge plays a substantial role in probabilistic graphical models (PGMs). The purpose of this study is to investigate a discriminative weight-learning method based on a medical knowledge network (MKN). We propose a training model called the maximum margin medical knowledge network (M 3 KN), which is strictly derived for calculating the weight of medical knowledge. Using the definition of a reasonable margin, the weight learning can be transformed into a margin optimization problem. To solve the optimization problem, we adopt a sequential minimal optimization (SMO) algorithm and the clique property of a Markov network. Ultimately, M 3 KN not only incorporates the inference ability of PGMs but also deals with high-dimensional logic knowledge. The experimental results indicate that M 3 KN obtains a higher F-measure score than the maximum likelihood learning algorithm of MKN for both Chinese Electronic Medical Records (CEMRs) and Blood Examination Records (BERs). Furthermore, the proposed approach is obviously superior to some classical machine learning algorithms for medical diagnosis. To adequately manifest the importance of domain knowledge, we numerically verify that the diagnostic accuracy of M 3 KN is gradually improved as the number of learned CEMRs increase, which contain important medical knowledge. Our experimental results show that the proposed method performs reliably for learning the weights of medical knowledge. M 3 KN outperforms other existing methods by achieving an F-measure of 0.731 for CEMRs and 0.4538 for BERs. This further illustrates that M 3 KN can facilitate the investigations of intelligent healthcare. Copyright © 2018 Elsevier B.V. All rights reserved.
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Wang, Zhaodi; Hu, Menghan; Zhai, Guangtao
2018-04-07
Deep learning has become a widely used powerful tool in many research fields, although not much so yet in agriculture technologies. In this work, two deep convolutional neural networks (CNN), viz. Residual Network (ResNet) and its improved version named ResNeXt, are used to detect internal mechanical damage of blueberries using hyperspectral transmittance data. The original structure and size of hypercubes are adapted for the deep CNN training. To ensure that the models are applicable to hypercube, we adjust the number of filters in the convolutional layers. Moreover, a total of 5 traditional machine learning algorithms, viz. Sequential Minimal Optimization (SMO), Linear Regression (LR), Random Forest (RF), Bagging and Multilayer Perceptron (MLP), are performed as the comparison experiments. In terms of model assessment, k-fold cross validation is used to indicate that the model performance does not vary with the different combination of dataset. In real-world application, selling damaged berries will lead to greater interest loss than discarding the sound ones. Thus, precision, recall, and F1-score are also used as the evaluation indicators alongside accuracy to quantify the false positive rate. The first three indicators are seldom used by investigators in the agricultural engineering domain. Furthermore, ROC curves and Precision-Recall curves are plotted to visualize the performance of classifiers. The fine-tuned ResNet/ResNeXt achieve average accuracy and F1-score of 0.8844/0.8784 and 0.8952/0.8905, respectively. Classifiers SMO/ LR/RF/Bagging/MLP obtain average accuracy and F1-score of 0.8082/0.7606/0.7314/0.7113/0.7827 and 0.8268/0.7796/0.7529/0.7339/0.7971, respectively. Two deep learning models achieve better classification performance than the traditional machine learning methods. Classification for each testing sample only takes 5.2 ms and 6.5 ms respectively for ResNet and ResNeXt, indicating that the deep learning framework has great potential for online fruit sorting. The results of this study demonstrate the potential of deep CNN application on analyzing the internal mechanical damage of fruit.
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Hu, Menghan; Zhai, Guangtao
2018-01-01
Deep learning has become a widely used powerful tool in many research fields, although not much so yet in agriculture technologies. In this work, two deep convolutional neural networks (CNN), viz. Residual Network (ResNet) and its improved version named ResNeXt, are used to detect internal mechanical damage of blueberries using hyperspectral transmittance data. The original structure and size of hypercubes are adapted for the deep CNN training. To ensure that the models are applicable to hypercube, we adjust the number of filters in the convolutional layers. Moreover, a total of 5 traditional machine learning algorithms, viz. Sequential Minimal Optimization (SMO), Linear Regression (LR), Random Forest (RF), Bagging and Multilayer Perceptron (MLP), are performed as the comparison experiments. In terms of model assessment, k-fold cross validation is used to indicate that the model performance does not vary with the different combination of dataset. In real-world application, selling damaged berries will lead to greater interest loss than discarding the sound ones. Thus, precision, recall, and F1-score are also used as the evaluation indicators alongside accuracy to quantify the false positive rate. The first three indicators are seldom used by investigators in the agricultural engineering domain. Furthermore, ROC curves and Precision-Recall curves are plotted to visualize the performance of classifiers. The fine-tuned ResNet/ResNeXt achieve average accuracy and F1-score of 0.8844/0.8784 and 0.8952/0.8905, respectively. Classifiers SMO/ LR/RF/Bagging/MLP obtain average accuracy and F1-score of 0.8082/0.7606/0.7314/0.7113/0.7827 and 0.8268/0.7796/0.7529/0.7339/0.7971, respectively. Two deep learning models achieve better classification performance than the traditional machine learning methods. Classification for each testing sample only takes 5.2 ms and 6.5 ms respectively for ResNet and ResNeXt, indicating that the deep learning framework has great potential for online fruit sorting. The results of this study demonstrate the potential of deep CNN application on analyzing the internal mechanical damage of fruit. PMID:29642454
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Liu, Xing; Wang, Xuefeng; Wang, Qiang; Andrews, Lester
2013-06-28
Reactions of laser-ablated V, Nb and Ta atoms with SO2 in excess argon during condensation gave new absorptions in the M=O stretching region, which were assigned to metal sulfide oxides SMO2 and anions SMO2(-) (M = V, Nb, Ta). The metal oxide complex OV(η(2)-SO) was also identified through the V=O and the characteristic side-on coordinated S-O stretching modes. The assignments of major vibrational modes were confirmed by appropriate S(18)O2 and (34)SO2 isotopic shifts, and density functional frequency calculations. DFT calculations were employed to study the behavior of reactions of Group V bare metal atoms with SO2, and a representative profile was derived which not only showed the preferred coordinating fashion of metal atoms but also tracked the path of S-O bond activation. The η(2)-O,O' bridge coordinated complexes are preferred with energy decreases of ca. 50 kcal mol(-1) for all three metals, which facilitate the activation of two S-O bonds in succession and finally direct the reaction to the most stable molecules SMO2 (M = V, Nb, Ta) along the potential energy surface (PES). Finally the SMO2 molecules capture electrons to give anions SMO2(-) with about 3.6 eV electron affinities based on DFT calculations.
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The Hedgehog processing pathway is required for NSCLC growth and survival
Rodriguez-Blanco, Jezabel; Schilling, Neal S.; Tokhunts, Robert; Giambelli, Camilla; Long, Jun; Liang Fei, Dennis; Singh, Samer; Black, Kendall E.; Wang, Zhiqiang; Galimberti, Fabrizio; Bejarano, Pablo A.; Elliot, Sharon; Glassberg, Marilyn K.; Nguyen, Dao M.; Lockwood, William W.; Lam, Wan L.; Dmitrovsky, Ethan; Capobianco, Anthony J.; Robbins, David J.
2013-01-01
Considerable interest has been generated from the results of recent clinical trials using SMOOTHENED (SMO) antagonists to inhibit the growth of HEDGEHOG (HH) signaling dependent tumors. This interest is tempered by the discovery of SMO mutations mediating resistance, underscoring the rationale for developing therapeutic strategies that interrupt HH signaling at levels distinct from those inhibiting SMO function. Here, we demonstrate that HH dependent non-small cell lung carcinoma (NSCLC) growth is sensitive to blockade of the HH pathway upstream of SMO, at the level of HH ligand processing. Individually, the use of different lentivirally delivered shRNA constructs targeting two functionally distinct HH-processing proteins, SKINNY HEDGEHOG (SKN) or DISPATCHED-1 (DISP-1), in NSCLC cell lines produced similar decreases in cell proliferation and increased cell death. Further, providing either an exogenous source of processed HH or a SMO agonist reverses these effects. The attenuation of HH processing, by knocking down either of these gene products, also abrogated tumor growth in mouse xenografts. Finally, we extended these findings to primary clinical specimens, showing that SKN is frequently over-expressed in NSCLC and that higher DISP-1 expression is associated with an unfavorable clinical outcome. Our results show a critical role for HH processing in HH-dependent tumors, identifies two potential druggable targets in the HH pathway, and suggest that similar therapeutic strategies could be explored to treat patients harboring HH ligand dependent cancers. PMID:22733134
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Long range personalized cancer treatment strategies incorporating evolutionary dynamics.
Yeang, Chen-Hsiang; Beckman, Robert A
2016-10-22
Current cancer precision medicine strategies match therapies to static consensus molecular properties of an individual's cancer, thus determining the next therapeutic maneuver. These strategies typically maintain a constant treatment while the cancer is not worsening. However, cancers feature complicated sub-clonal structure and dynamic evolution. We have recently shown, in a comprehensive simulation of two non-cross resistant therapies across a broad parameter space representing realistic tumors, that substantial improvement in cure rates and median survival can be obtained utilizing dynamic precision medicine strategies. These dynamic strategies explicitly consider intratumoral heterogeneity and evolutionary dynamics, including predicted future drug resistance states, and reevaluate optimal therapy every 45 days. However, the optimization is performed in single 45 day steps ("single-step optimization"). Herein we evaluate analogous strategies that think multiple therapeutic maneuvers ahead, considering potential outcomes at 5 steps ahead ("multi-step optimization") or 40 steps ahead ("adaptive long term optimization (ALTO)") when recommending the optimal therapy in each 45 day block, in simulations involving both 2 and 3 non-cross resistant therapies. We also evaluate an ALTO approach for situations where simultaneous combination therapy is not feasible ("Adaptive long term optimization: serial monotherapy only (ALTO-SMO)"). Simulations utilize populations of 764,000 and 1,700,000 virtual patients for 2 and 3 drug cases, respectively. Each virtual patient represents a unique clinical presentation including sizes of major and minor tumor subclones, growth rates, evolution rates, and drug sensitivities. While multi-step optimization and ALTO provide no significant average survival benefit, cure rates are significantly increased by ALTO. Furthermore, in the subset of individual virtual patients demonstrating clinically significant difference in outcome between approaches, by far the majority show an advantage of multi-step or ALTO over single-step optimization. ALTO-SMO delivers cure rates superior or equal to those of single- or multi-step optimization, in 2 and 3 drug cases respectively. In selected virtual patients incurable by dynamic precision medicine using single-step optimization, analogous strategies that "think ahead" can deliver long-term survival and cure without any disadvantage for non-responders. When therapies require dose reduction in combination (due to toxicity), optimal strategies feature complex patterns involving rapidly interleaved pulses of combinations and high dose monotherapy. This article was reviewed by Wendy Cornell, Marek Kimmel, and Andrzej Swierniak. Wendy Cornell and Andrzej Swierniak are external reviewers (not members of the Biology Direct editorial board). Andrzej Swierniak was nominated by Marek Kimmel.
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A reduced-order nonlinear sliding mode observer for vehicle slip angle and tyre forces
NASA Astrophysics Data System (ADS)
Chen, Yuhang; Ji, Yunfeng; Guo, Konghui
2014-12-01
In this paper, a reduced-order sliding mode observer (RO-SMO) is developed for vehicle state estimation. Several improvements are achieved in this paper. First, the reference model accuracy is improved by considering vehicle load transfers and using a precise nonlinear tyre model 'UniTire'. Second, without the reference model accuracy degraded, the computing burden of the state observer is decreased by a reduced-order approach. Third, nonlinear system damping is integrated into the SMO to speed convergence and reduce chattering. The proposed RO-SMO is evaluated through simulation and experiments based on an in-wheel motor electric vehicle. The results show that the proposed observer accurately predicts the vehicle states.
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CoSMoS: Conserved Sequence Motif Search in the proteome
Liu, Xiao I; Korde, Neeraj; Jakob, Ursula; Leichert, Lars I
2006-01-01
Background With the ever-increasing number of gene sequences in the public databases, generating and analyzing multiple sequence alignments becomes increasingly time consuming. Nevertheless it is a task performed on a regular basis by researchers in many labs. Results We have now created a database called CoSMoS to find the occurrences and at the same time evaluate the significance of sequence motifs and amino acids encoded in the whole genome of the model organism Escherichia coli K12. We provide a precomputed set of multiple sequence alignments for each individual E. coli protein with all of its homologues in the RefSeq database. The alignments themselves, information about the occurrence of sequence motifs together with information on the conservation of each of the more than 1.3 million amino acids encoded in the E. coli genome can be accessed via the web interface of CoSMoS. Conclusion CoSMoS is a valuable tool to identify highly conserved sequence motifs, to find regions suitable for mutational studies in functional analyses and to predict important structural features in E. coli proteins. PMID:16433915
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GLI activation by atypical protein kinase C ι/λ regulates the growth of basal cell carcinomas.
Atwood, Scott X; Li, Mischa; Lee, Alex; Tang, Jean Y; Oro, Anthony E
2013-02-28
Growth of basal cell carcinomas (BCCs) requires high levels of hedgehog (HH) signalling through the transcription factor GLI. Although inhibitors of membrane protein smoothened (SMO) effectively suppress HH signalling, early tumour resistance illustrates the need for additional downstream targets for therapy. Here we identify atypical protein kinase C ι/λ (aPKC-ι/λ) as a novel GLI regulator in mammals. aPKC-ι/λ and its polarity signalling partners co-localize at the centrosome and form a complex with missing-in-metastasis (MIM), a scaffolding protein that potentiates HH signalling. Genetic or pharmacological loss of aPKC-ι/λ function blocks HH signalling and proliferation of BCC cells. Prkci is a HH target gene that forms a positive feedback loop with GLI and exists at increased levels in BCCs. Genome-wide transcriptional profiling shows that aPKC-ι/λ and SMO control the expression of similar genes in tumour cells. aPKC-ι/λ functions downstream of SMO to phosphorylate and activate GLI1, resulting in maximal DNA binding and transcriptional activation. Activated aPKC-ι/λ is upregulated in SMO-inhibitor-resistant tumours and targeting aPKC-ι/λ suppresses signalling and growth of resistant BCC cell lines. These results demonstrate that aPKC-ι/λ is critical for HH-dependent processes and implicates aPKC-ι/λ as a new, tumour-selective therapeutic target for the treatment of SMO-inhibitor-resistant cancers.
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CoSMoS and TwinPaW: initial report on two new German twin studies.
Spinath, Frank M; Wolf, Heike
2006-12-01
After briefly recapitulating two earlier German twin studies (BiLSAT and GOSAT), we present two new German twin studies with a longitudinal perspective: CoSMoS and TwinPaW. The twin study on Cognitive ability, Self-reported Motivation and School performance (CoSMoS) aims to investigate predictors and influences of school performance in a genetically sensitive design, beginning with children in late elementary school. The Twin study on Personality And Wellbeing (TwinPaW) focuses on adult personality and its relation to physical health as well as health-related behavior in an adult sample of twins. Both studies are characterized by an effort to recruit new large twin samples through a novel recruitment procedure aimed at reducing self-selective sampling. In two German federal states, contact information on persons born on the same day and with the same name was retrieved from record sections. From the resulting pool of more than 36,000 addresses we contacted approximately 2000 parents of twins aged 9 and 10 for CoSMoS, as well as 2000 adult twin pairs for TwinPaW by telephone and mail. Personal contact by telephone proved to be more efficient with agreement rates of 63% in the children sample and 65% in the adult sample. In this article we briefly describe the rationale and the study aims of CoSMoS and TwinPaW as well as the characteristics of the sample we have recruited so far.
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Martínez, Paula; Huedo, Pol; Martinez-Servat, Sònia; Planell, Raquel; Ferrer-Navarro, Mario; Daura, Xavier; Yero, Daniel; Gibert, Isidre
2015-01-01
Quorum Sensing (QS) mediated by Acyl Homoserine Lactone (AHL) molecules are probably the most widespread and studied among Gram-negative bacteria. Canonical AHL systems are composed by a synthase (LuxI family) and a regulator element (LuxR family), whose genes are usually adjacent in the genome. However, incomplete AHL-QS machinery lacking the synthase LuxI is frequently observed in Proteobacteria, and the regulator element is then referred as LuxR solo. It has been shown that certain LuxR solos participate in interspecific communication by detecting signals produced by different organisms. In the case of Stenotrophomonas maltophilia, a preliminary genome sequence analysis revealed numerous putative luxR genes, none of them associated to a luxI gene. From these, the hypothetical LuxR solo Smlt1839, here designated SmoR, presents a conserved AHL binding domain and a helix-turn-helix DNA binding motif. Its genomic organization-adjacent to hchA gene-indicate that SmoR belongs to the new family "LuxR regulator chaperone HchA-associated." AHL-binding assays revealed that SmoR binds to AHLs in-vitro, at least to oxo-C8-homoserine lactone, and it regulates operon transcription, likely by recognizing a conserved palindromic regulatory box in the hchA upstream region. Supplementation with concentrated supernatants from Pseudomonas aeruginosa, which contain significant amounts of AHLs, promoted swarming motility in S. maltophilia. Contrarily, no swarming stimulation was observed when the P. aeruginosa supernatant was treated with the lactonase AiiA from Bacillus subtilis, confirming that AHL contributes to enhance the swarming ability of S. maltophilia. Finally, mutation of smoR resulted in a swarming alteration and an apparent insensitivity to the exogenous AHLs provided by P. aeruginosa. In conclusion, our results demonstrate that S. maltophilia senses AHLs produced by neighboring bacteria through the LuxR solo SmoR, regulating population behaviors such as swarming motility.
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Impact of topographic mask models on scanner matching solutions
NASA Astrophysics Data System (ADS)
Tyminski, Jacek K.; Pomplun, Jan; Renwick, Stephen P.
2014-03-01
Of keen interest to the IC industry are advanced computational lithography applications such as Optical Proximity Correction of IC layouts (OPC), scanner matching by optical proximity effect matching (OPEM), and Source Optimization (SO) and Source-Mask Optimization (SMO) used as advanced reticle enhancement techniques. The success of these tasks is strongly dependent on the integrity of the lithographic simulators used in computational lithography (CL) optimizers. Lithographic mask models used by these simulators are key drivers impacting the accuracy of the image predications, and as a consequence, determine the validity of these CL solutions. Much of the CL work involves Kirchhoff mask models, a.k.a. thin masks approximation, simplifying the treatment of the mask near-field images. On the other hand, imaging models for hyper-NA scanner require that the interactions of the illumination fields with the mask topography be rigorously accounted for, by numerically solving Maxwell's Equations. The simulators used to predict the image formation in the hyper-NA scanners must rigorously treat the masks topography and its interaction with the scanner illuminators. Such imaging models come at a high computational cost and pose challenging accuracy vs. compute time tradeoffs. Additional complication comes from the fact that the performance metrics used in computational lithography tasks show highly non-linear response to the optimization parameters. Finally, the number of patterns used for tasks such as OPC, OPEM, SO, or SMO range from tens to hundreds. These requirements determine the complexity and the workload of the lithography optimization tasks. The tools to build rigorous imaging optimizers based on first-principles governing imaging in scanners are available, but the quantifiable benefits they might provide are not very well understood. To quantify the performance of OPE matching solutions, we have compared the results of various imaging optimization trials obtained with Kirchhoff mask models to those obtained with rigorous models involving solutions of Maxwell's Equations. In both sets of trials, we used sets of large numbers of patterns, with specifications representative of CL tasks commonly encountered in hyper-NA imaging. In this report we present OPEM solutions based on various mask models and discuss the models' impact on hyper- NA scanner matching accuracy. We draw conclusions on the accuracy of results obtained with thin mask models vs. the topographic OPEM solutions. We present various examples representative of the scanner image matching for patterns representative of the current generation of IC designs.
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Amine oxidase-based biosensors for spermine and spermidine determination.
Boffi, Alberto; Favero, Gabriele; Federico, Rodolfo; Macone, Alberto; Antiochia, Riccarda; Tortolini, Cristina; Sanzó, Gabriella; Mazzei, Franco
2015-02-01
The present work describes the development and optimization of electrochemical biosensors for specific determination of the biogenic polyamine spermine (Spm) and spermidine (Spmd) whose assessment represents a novel important analytical tool in food analysis and human diagnostics. These biosensors have been prepared using novel engineered enzymes: polyamine oxidase (PAO) endowed with selectivity towards Spm and Spmd and spermine oxidase (SMO) characterized by strict specificity towards Spm. The current design entails biosensors in which the enzymes were entrapped in poly(vinyl alcohol) bearing styrylpyridinium groups (PVA-SbQ), a photocrosslinkable gel, onto an electrode surface. Screen-printed electrodes (SPEs) were used as electrochemical transducers for enzymatically produced hydrogen peroxide, operating at different potential vs Ag/AgCl according to the material of the working electrode (WE): +700 mV for graphite (GP) or -100 mV for Prussian blue (PB)-modified SPE, respectively. Biosensor performances were evaluated by means of flow injection amperometric (FIA) measurements. The modified electrodes showed good sensitivity, long-term stability and reproducibility. Under optimal conditions, the PAO biosensor showed a linear range 0.003-0.3 mM for Spm and 0.01-0.4 mM for Spmd, while with the SMO biosensor, a linear range of 0.004-0.5 mM for Spm has been obtained. The main kinetic parameters apparent Michaelis constant (K M), turnover number (K cat) and steady-state current (I max) were determined. The proposed device was then applied to the determination of biogenic amines in blood samples. The results obtained were in good agreement with those obtained with the GC-MS reference method.
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The influence of negative training set size on machine learning-based virtual screening.
Kurczab, Rafał; Smusz, Sabina; Bojarski, Andrzej J
2014-01-01
The paper presents a thorough analysis of the influence of the number of negative training examples on the performance of machine learning methods. The impact of this rather neglected aspect of machine learning methods application was examined for sets containing a fixed number of positive and a varying number of negative examples randomly selected from the ZINC database. An increase in the ratio of positive to negative training instances was found to greatly influence most of the investigated evaluating parameters of ML methods in simulated virtual screening experiments. In a majority of cases, substantial increases in precision and MCC were observed in conjunction with some decreases in hit recall. The analysis of dynamics of those variations let us recommend an optimal composition of training data. The study was performed on several protein targets, 5 machine learning algorithms (SMO, Naïve Bayes, Ibk, J48 and Random Forest) and 2 types of molecular fingerprints (MACCS and CDK FP). The most effective classification was provided by the combination of CDK FP with SMO or Random Forest algorithms. The Naïve Bayes models appeared to be hardly sensitive to changes in the number of negative instances in the training set. In conclusion, the ratio of positive to negative training instances should be taken into account during the preparation of machine learning experiments, as it might significantly influence the performance of particular classifier. What is more, the optimization of negative training set size can be applied as a boosting-like approach in machine learning-based virtual screening.
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The influence of negative training set size on machine learning-based virtual screening
2014-01-01
Background The paper presents a thorough analysis of the influence of the number of negative training examples on the performance of machine learning methods. Results The impact of this rather neglected aspect of machine learning methods application was examined for sets containing a fixed number of positive and a varying number of negative examples randomly selected from the ZINC database. An increase in the ratio of positive to negative training instances was found to greatly influence most of the investigated evaluating parameters of ML methods in simulated virtual screening experiments. In a majority of cases, substantial increases in precision and MCC were observed in conjunction with some decreases in hit recall. The analysis of dynamics of those variations let us recommend an optimal composition of training data. The study was performed on several protein targets, 5 machine learning algorithms (SMO, Naïve Bayes, Ibk, J48 and Random Forest) and 2 types of molecular fingerprints (MACCS and CDK FP). The most effective classification was provided by the combination of CDK FP with SMO or Random Forest algorithms. The Naïve Bayes models appeared to be hardly sensitive to changes in the number of negative instances in the training set. Conclusions In conclusion, the ratio of positive to negative training instances should be taken into account during the preparation of machine learning experiments, as it might significantly influence the performance of particular classifier. What is more, the optimization of negative training set size can be applied as a boosting-like approach in machine learning-based virtual screening. PMID:24976867
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Regaining motor control in musician's dystonia by restoring sensorimotor organization.
Rosenkranz, Karin; Butler, Katherine; Williamon, Aaron; Rothwell, John C
2009-11-18
Professional musicians are an excellent model of long-term motor learning effects on structure and function of the sensorimotor system. However, intensive motor skill training has been associated with task-specific deficiency in hand motor control, which has a higher prevalence among musicians (musician's dystonia) than in the general population. Using a transcranial magnetic stimulation paradigm, we previously found an expanded spatial integration of proprioceptive input into the hand motor cortex [sensorimotor organization (SMO)] in healthy musicians. In musician's dystonia, however, this expansion was even larger. Whereas motor skills of musicians are likely to be supported by a spatially expanded SMO, we hypothesized that in musician's dystonia this might have developed too far and now disrupts rather than assists task-specific motor control. If so, motor control should be regained by reversing the excessive reorganization in musician's dystonia. Here, we test this hypothesis and show that a 15 min intervention with proprioceptive input (proprioceptive training) restored SMO in pianists with musician's dystonia to the pattern seen in healthy pianists. Crucially, task-specific motor control improved significantly and objectively as measured with a MIDI (musical instrument digital interface) piano, and the amount of behavioral improvement was significantly correlated to the degree of sensorimotor reorganization. In healthy pianists and nonmusicians, the SMO and motor performance remained essentially unchanged. These findings suggest that the differentiation of SMO in the hand motor cortex and the degree of motor control of intensively practiced tasks are significantly linked and finely balanced. Proprioceptive training restored this balance in musician's dystonia to the behaviorally beneficial level of healthy musicians.
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Suppression of hedgehog signaling regulates hepatic stellate cell activation and collagen secretion.
Li, Tao; Leng, Xi-Sheng; Zhu, Ji-Ye; Wang, Gang
2015-01-01
Hepatic stellate cells (HSCs) play an important role in liver fibrosis. This study investigates the expression of hedgehog in HSC and the role of hedgehog signaling on activation and collagen secretion of HSC. Liver ex vivo perfusion with collagenase IV and density gradient centrifugation were used to isolate HSC. Expression of hedgehog signaling components Ihh, Smo, Ptc, Gli2 and Gli3 in HSC were detected by RT-PCR. Hedgehog siRNA vectors targeting Ihh, Smo and Gli2 were constructed and transfected into HSC respectively. Suppression of hedgehog signaling were detected by SYBR Green fluorescence quantitative RT-PCR. Effects of hedgehog signaling inhibition on HSC activation and collagen I secretion were analyzed. Hedgehog signaling components Ihh, Smo, Ptc, Gli2 and Gli3 were expressed in HSC. siRNA vectors targeting Ihh, Smo and Gli2 were successfully constructed and decreased target gene expression. Suppression of hedgehog signaling significantly decreased the expression of α-SMA in HSC (P<0.01). Collagen type I secretion of HSC were also significantly decreased (P<0.01). In summary, HSC activation and collagen secretion can be regulated by hedgehog signaling. Hedgehog may play a role in the pathogenesis of liver fibrosis.
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Onyewu, Samuel C; Ogundimu, Ololade O; Ortega, Gezzer; Bauer, Edward S; Emenari, Chijindu C; Molyneaux, Neh D; Layne, Sylvonne A; Changoor, Navin R; Tapscott, Denia; Tran, Daniel D; Fullum, Terrence M
2017-01-01
Super morbid obesity (body mass index [BMI] > 50 kg/m 2 ) is associated with significant comorbidities and is disparagingly prevalent among the black population. There is paucity of data regarding bariatric surgery outcomes among super morbid obese (SMO) blacks. Our aim is to evaluate the reduction in weight and resolution of comorbidities after bariatric surgery among SMO black patients at an urban academic institution. A retrospective review of SMO black patients who underwent bariatric surgery from August 2008 to June 2013 at Howard University Hospital. Outcomes of interest include weight loss, improvement or resolution of hypertension, type 2 diabetes, and hyperlipidemia at 12 months. Eighty-seven patients met our inclusion criteria. Mean preoperative weight and BMI were 347.2 lbs and 56.8 kg/m 2 , respectively. At 12 months, mean weight and BMI were 245.3 lbs and 40.1 kg/m 2 , respectively. There was also significant improvement or resolution of hypertension, type 2 diabetes, and hyperlipidemia. Bariatric surgery may result in significant weight loss and improvement or resolution of comorbidities in SMO black patients. Copyright © 2016. Published by Elsevier Inc.
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Hamso, Magni; Ramsdell, Amanda; Balmer, Dorene; Boquin, Cyrus
2012-01-01
Although medical students are expected to teach as soon as they begin residency, medical schools have just recently begun adding teacher training to their curricula. Student-run clinics (SRCs) may provide opportunities in clinical teaching before residency. The aim of this pilot study was to examine students' experiences in clinical teaching at Columbia Student Medical Outreach (CoSMO), Columbia University's SRC, during the 2009-2010 school year. A mixed-methods approach was used. Data included closed and open-ended surveys (n = 34), combined interviews with preclinical and clinical student pairs (n = 5), individual interviews (n = 10), and focus groups (n = 3). The transcripts were analyzed using the principles of grounded theory. Many students had their first clinical teaching experience while volunteering at CoSMO. Clinical students' ability to teach affected the quality of the learning experience for their preclinical peers. Preclinical students who asked questions and engaged in patient care challenged their clinical peers to balance teaching with patient care. Clinical students began to see themselves as teachers while volunteering at CoSMO. The practical experiences in clinical teaching that students have at SRCs can supplement classroom-based trainings. Medical schools might revisit their SRCs as places for exposure to clinical teaching.
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A Counter-Social Movement Approach to Deconstructing Daesh
alternative, the US military could view Daesh as a transnational social movement organization (SMO), and by doing so, planners could develop a more effective... social movement theory (SMT) to determine lines of effort (LOE) against which US military forces could best apply resources to counteract the SMO. This... study is divided into four sections. The first section constitutes an overview of SMT as a form of contentious politics. The second section presents a
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Crevice Corrosion Behavior of 45 Molybdenum-Containing Stainless Steels in Seawater.
1981-12-01
Armco, Avesta Jernverks, Cabot, Carpenter Technology, Crucible, Eastern, Firth-Brown, Huntington, Jessup, Langley Alloys, and Uddeholm. 16...Department of Energy, Report ANL/OTEC-BCM-022. 7. Wallen, B., and M. Liljas, " Avesta 254 SMO - A New, High Molybdenum Stainless Steel," presented at NKM8...1977).; 11. Wallen, B., " Avesta 254 SMO - A Stainless Steel for Seawater Service," presented at the Advanced Stainless Steels for Turbine Condensors
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JWST-MIRI spectrometer main optics design and main results
NASA Astrophysics Data System (ADS)
Navarro, Ramón; Schoenmaker, Ton; Kroes, Gabby; Oudenhuysen, Ad; Jager, Rieks; Venema, Lars
2017-11-01
MIRI ('Mid InfraRed Instrument') is the combined imager and integral field spectrometer for the 5-29 micron wavelength range under development for the James Webb Space Telescope JWST. The flight acceptance tests of the Spectrometer Main Optics flight models (SMO), part of the MIRI spectrometer, are completed in the summer of 2008 and the system is delivered to the MIRI-JWST consortium. The two SMO arms contain 14 mirrors and form the MIRI optical system together with 12 selectable gratings on grating wheels. The entire system operates at a temperature of 7 Kelvin and is designed on the basis of a 'no adjustments' philosophy. This means that the optical alignment precision depends strongly on the design, tolerance analysis and detailed knowledge of the manufacturing process. Because in principle no corrections are needed after assembly, continuous tracking of the alignment performance during the design and manufacturing phases is important. The flight hardware is inspected with respect to performance parameters like alignment and image quality. The stability of these parameters is investigated after exposure to various vibration levels and successive cryogenic cool downs. This paper describes the philosophy behind the acceptance tests, the chosen test strategy and reports the results of these tests. In addition the paper covers the design of the optical test setup, focusing on the simulation of the optical interfaces of the SMO. Also the relation to the SMO qualification and verification program is addressed.
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Sanghez, Valentina; Chen, Mengqing; Li, Shan; Chou, Tsui-Fen; Iacovino, Michelina; Lin, Henry J; Lasky, Joseph L; Panosyan, Eduard H
2018-05-01
Anti-metabolites are less-myelosuppressive than DNA-damaging anticancer drugs and may be useful against brain tumors. We evaluated the asparagine/glutamine-deaminating agent Erwinaze with/without temozolomide against brain tumor cells and mouse medulloblastomas. Erwinaze treatment of cell lines and neurospheres led to dose-dependent reductions of cells (reversible by L-glutamine), with half maximal inhibitory concentrations (IC 50 s) of 0.12->10 IU/ml. Erwinaze at <1 IU/ml reduced temozolomide IC 50 s by 3.6- to 13-fold (300-1,200 μM to 40-330 μM). Seven-week-old SMO/SMO mice treated with Erwinaze (regardless of temozolomide treatment) had better survival 11 weeks post-therapy, compared to those not treated with Erwinaze (81.25% vs. 46.15, p=0.08). Temozolomide-treated mice developed 10% weight loss, impairing survival. All 16 mice treated with temozolomide (regardless of Erwinaze treatment) succumbed by 40-weeks of age, whereas 5/8 animals treated with Erwinaze alone and 2/6 controls survived (p=0.035). Erwinaze enhances cytotoxicity of temozolomide in vitro, and improves survival in SMO/SMO mice, likely by reducing cerebrospinal fluid glutamine. Temozolomide-associated toxicity prevented demonstration of any potential combinatorial advantage with Erwinaze in vivo. Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.
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NASA Astrophysics Data System (ADS)
Andrews, G. D.; Davila Harris, P.; Brown, S. R.; Anderson, L.; Moreno, N.
2014-12-01
We completed a field sampling transect across the northern Sierra Madre Occidental silicic large igneous province (SMO) in December 2013. Here we present the first stratigraphic, petrological, and geochemical data from the transect between Hidalgo del Parral and Guadalupe y Calvo, Chihuahua, Mexico. This is the first new transect across the SMO in 25 years and the only one between existing NE - SW transects at Chihuahua - Hermosillo and Durango - Mazatlan. The 245 km-long transect along Mexican Highway 24 crosses the boundary between the extended (Basin and Range) and non-extended (Sierra Madre Occidental plateau) parts of the SMO, and allows sampling of previously undescribed Oligocene (?) - early Miocene (?) rhyolitic ignimbrites and lavas, and occasional post-rhyolite, Miocene (?) SCORBA basaltic andesite lavas. 54 samples of rhyolitic ignimbrites (40) and lavas (7), and basaltic andesite lavas (7) were sampled along the transect, including 8 canyon sections with more than one unit. The ignimbrites are overwhelming rhyodacitic (plagioclase and hornblende or biotite phyric) or rhyolitic (quartz (+/- sanidine) in additon to plagioclase and hornblende or biotite phyric) and sparsely to highly phyric. Preliminary petrographic (phenocryst abundances) and geochemical (major and trace element) will be presented and compared to existing data from elsewhere in the SMO. Future work will include U-Pb zircon dating and whole rock and in-zircon radiogenic isotopes analyses.
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Xu, Zhengwei; Huang, Chen; Hao, Dingjun
2017-02-01
MicroRNAs (miRNAs) have emerged as important regulators in multiple myeloma (MM). miR-1271 is a tumor suppressor in many cancer types. However, the biological role of miR-1271 in MM remains unclear. In the present study, we elucidated the biological role of miR-1271 in MM. Results showed that miR-1271 was significantly decreased in primary MM cells from MM patients and MM cell lines. Overexpression of miR-1271 inhibited proliferation and promoted apoptosis of MM cells. Conversely, suppression of miR-1271 showed the opposite effect. Bioinformatics algorithm analysis predicted that smoothened (SMO), the activator of Hedgehog (HH) signaling pathway, was a direct target of miR-1271 that was experimentally verified by a dual-luciferase reporter assay. Furthermore, overexpression of miR-1271 inhibited SMO expression and HH signaling pathway. Conversely, the restoration of SMO expression markedly abolished the effect of miR-1271 overexpression on cell proliferation, apoptosis and HH signaling pathway in MM cells. Taken together, the present study suggests that miR-1271 functions as a tumor suppressor that inhibits proliferation and promotes apoptosis of MM cells through inhibiting SMO-mediated HH signaling pathway. This finding implies that miR-1271 is a potential therapeutic target for the treatment of MM.
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NASA Astrophysics Data System (ADS)
O'Neill, A.
2015-12-01
The Coastal Storm Modeling System (CoSMoS) is a numerical modeling scheme used to predict coastal flooding due to sea level rise and storms influenced by climate change, currently in use in central California and in development for Southern California (Pt. Conception to the Mexican border). Using a framework of circulation, wave, analytical, and Bayesian models at different geographic scales, high-resolution results are translated as relevant hazards projections at the local scale that include flooding, wave heights, coastal erosion, shoreline change, and cliff failures. Ready access to accurate, high-resolution coastal flooding data is critical for further validation and refinement of CoSMoS and improved coastal hazard projections. High-resolution Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) provides an exceptional data source as appropriately-timed flights during extreme tides or storms provide a geographically-extensive method for determining areas of inundation and flooding extent along expanses of complex and varying coastline. Landward flood extents are numerically identified via edge-detection in imagery from single flights, and can also be ascertained via change detection using additional flights and imagery collected during average wave/tide conditions. The extracted flooding positions are compared against CoSMoS results for similar tide, water level, and storm-intensity conditions, allowing for robust testing and validation of CoSMoS and providing essential feedback for supporting regional and local model improvement.
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Feng, Qiang; Zhao, Wenwu; Fu, Bojie; Ding, Jingyi; Wang, Shuai
2017-12-31
Soil erosion control (SEC), carbon sequestration (CAS), and soil moisture (SMO) strongly interact in the semi-arid Loess Plateau. Since SMO has supportive effects on SEC and CAS, it can be considered as ecosystem service (ES), and there is an immediate need to coordinate the relationships among these ecosystem services (ESs) to promote the sustainability of vegetation recovery. In this study, we quantified the ESs, ES trade-offs, and the environmental factors in 151 sample plots in the Ansai watershed, and we used a redundancy analysis (RDA) to clarify the effects of environmental factors on these ESs and their trade-offs. The results were as follows: (1) the general trend in the SEC of vegetation types was Robinia pseudoacacia (CH)>native grass (NG)>small arbor (ST)>Hippophae rhamnoides (SJ)>artificial grass (AG)>Caragana korshinskii (NT)>apple orchard (GY)>crop (CP); the CAS trend was CH>SJ>NT>AG>CP>ST>GY>NG; and the SMO trend was CP>NG>GY>AG>SJ>ST>CH>NT. (2) For SEC-SMO trade-offs, the influence of vegetation type, altitude, silt and sand composition was dominant. The arrangement of NG, AG, and SJ could decrease the extent of the trade-offs. (3) For CAS-SMO trade-offs, vegetation coverage and types were the dominant factors, but the effects were not complex. The extent of these trade-offs was lowest for NT, and that for SJ was the second lowest. (4) Considering the relationships among the three ESs, SJ was the most appropriate afforestation plant. Combing the vegetation types, slope position, slope gradient, and soil properties could regulate these ES relationships. The dominant factors influencing ES trade-offs varied among the different soil layers, so we must consider the corresponding influencing factors to regulate ESs. Moreover, manual management measures were also important for coordinating the ES relationships. Our research provides a better understanding of the mechanisms influencing the relationships among ESs. Copyright © 2017 Elsevier B.V. All rights reserved.
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Validating the WHO maternal near miss tool: comparing high- and low-resource settings.
Witteveen, Tom; Bezstarosti, Hans; de Koning, Ilona; Nelissen, Ellen; Bloemenkamp, Kitty W; van Roosmalen, Jos; van den Akker, Thomas
2017-06-19
WHO proposed the WHO Maternal Near Miss (MNM) tool, classifying women according to several (potentially) life-threatening conditions, to monitor and improve quality of obstetric care. The objective of this study is to analyse merged data of one high- and two low-resource settings where this tool was applied and test whether the tool may be suitable for comparing severe maternal outcome (SMO) between these settings. Using three cohort studies that included SMO cases, during two-year time frames in the Netherlands, Tanzania and Malawi we reassessed all SMO cases (as defined by the original studies) with the WHO MNM tool (five disease-, four intervention- and seven organ dysfunction-based criteria). Main outcome measures were prevalence of MNM criteria and case fatality rates (CFR). A total of 3172 women were studied; 2538 (80.0%) from the Netherlands, 248 (7.8%) from Tanzania and 386 (12.2%) from Malawi. Total SMO detection was 2767 (87.2%) for disease-based criteria, 2504 (78.9%) for intervention-based criteria and 1211 (38.2%) for organ dysfunction-based criteria. Including every woman who received ≥1 unit of blood in low-resource settings as life-threatening, as defined by organ dysfunction criteria, led to more equally distributed populations. In one third of all Dutch and Malawian maternal death cases, organ dysfunction criteria could not be identified from medical records. Applying solely organ dysfunction-based criteria may lead to underreporting of SMO. Therefore, a tool based on defining MNM only upon establishing organ failure is of limited use for comparing settings with varying resources. In low-resource settings, lowering the threshold of transfused units of blood leads to a higher detection rate of MNM. We recommend refined disease-based criteria, accompanied by a limited set of intervention- and organ dysfunction-based criteria to set a measure of severity.
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RET selection on state-of-the-art NAND flash
NASA Astrophysics Data System (ADS)
Lafferty, Neal V.; He, Yuan; Pei, Jinhua; Shao, Feng; Liu, QingWei; Shi, Xuelong
2015-03-01
We present results generated using a new gauge-based Resolution Enhancement Technique (RET) Selection flow during the technology set up phase of a 3x-node NAND Flash product. As a testcase, we consider a challenging critical level for this ash product. The RET solutions include inverse lithography technology (ILT) optimized masks with sub-resolution assist features (SRAF) and companion illumination sources developed using a new pixel based Source Mask Optimization (SMO) tool that uses measurement gauges as a primary input. The flow includes verification objectives which allow tolerancing of particular measurement gauges based on lithographic criteria. Relative importance for particular gauges may also be set, to aid in down-selection from several candidate sources. The end result is a sensitive, objective score of RET performance. Using these custom-defined importance metrics, decisions on the final RET style can be made in an objective way.
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Role of Polyamine Oxidase (PAOh1/SMO) in Human Breast Cancer
2007-04-01
polyamine spermidine , 3-aminopropanal, and the reactive oxygen species, H2O2. Previous work by our research group has shown that SMO can be induced by...spermine/ spermidine N1-acetyltransferase (SSAT). Treatment of MCF-10a cells with CSE resulted in a rapid 3-fold induction of SSAT mRNA at the one hour time...and spermine/ spermidine N1 acetyl- transferase (SSAT, open bars) in MCF- 10a human breast cancer cells by cigarette smoke extract (CSE) at the
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Molecular evolution of the polyamine oxidase gene family in Metazoa
2012-01-01
Background Polyamine oxidase enzymes catalyze the oxidation of polyamines and acetylpolyamines. Since polyamines are basic regulators of cell growth and proliferation, their homeostasis is crucial for cell life. Members of the polyamine oxidase gene family have been identified in a wide variety of animals, including vertebrates, arthropodes, nematodes, placozoa, as well as in plants and fungi. Polyamine oxidases (PAOs) from yeast can oxidize spermine, N1-acetylspermine, and N1-acetylspermidine, however, in vertebrates two different enzymes, namely spermine oxidase (SMO) and acetylpolyamine oxidase (APAO), specifically catalyze the oxidation of spermine, and N1-acetylspermine/N1-acetylspermidine, respectively. Little is known about the molecular evolutionary history of these enzymes. However, since the yeast PAO is able to catalyze the oxidation of both acetylated and non acetylated polyamines, and in vertebrates these functions are addressed by two specialized polyamine oxidase subfamilies (APAO and SMO), it can be hypothesized an ancestral reference for the former enzyme from which the latter would have been derived. Results We analysed 36 SMO, 26 APAO, and 14 PAO homologue protein sequences from 54 taxa including various vertebrates and invertebrates. The analysis of the full-length sequences and the principal domains of vertebrate and invertebrate PAOs yielded consensus primary protein sequences for vertebrate SMOs and APAOs, and invertebrate PAOs. This analysis, coupled to molecular modeling techniques, also unveiled sequence regions that confer specific structural and functional properties, including substrate specificity, by the different PAO subfamilies. Molecular phylogenetic trees revealed a basal position of all the invertebrates PAO enzymes relative to vertebrate SMOs and APAOs. PAOs from insects constitute a monophyletic clade. Two PAO variants sampled in the amphioxus are basal to the dichotomy between two well supported monophyletic clades including, respectively, all the SMOs and APAOs from vertebrates. The two vertebrate monophyletic clades clustered strictly mirroring the organismal phylogeny of fishes, amphibians, reptiles, birds, and mammals. Evidences from comparative genomic analysis, structural evolution and functional divergence in a phylogenetic framework across Metazoa suggested an evolutionary scenario where the ancestor PAO coding sequence, present in invertebrates as an orthologous gene, has been duplicated in the vertebrate branch to originate the paralogous SMO and APAO genes. A further genome evolution event concerns the SMO gene of placental, but not marsupial and monotremate, mammals which increased its functional variation following an alternative splicing (AS) mechanism. Conclusions In this study the explicit integration in a phylogenomic framework of phylogenetic tree construction, structure prediction, and biochemical function data/prediction, allowed inferring the molecular evolutionary history of the PAO gene family and to disambiguate paralogous genes related by duplication event (SMO and APAO) and orthologous genes related by speciation events (PAOs, SMOs/APAOs). Further, while in vertebrates experimental data corroborate SMO and APAO molecular function predictions, in invertebrates the finding of a supported phylogenetic clusters of insect PAOs and the co-occurrence of two PAO variants in the amphioxus urgently claim the need for future structure-function studies. PMID:22716069
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Molecular evolution of the polyamine oxidase gene family in Metazoa.
Polticelli, Fabio; Salvi, Daniele; Mariottini, Paolo; Amendola, Roberto; Cervelli, Manuela
2012-06-20
Polyamine oxidase enzymes catalyze the oxidation of polyamines and acetylpolyamines. Since polyamines are basic regulators of cell growth and proliferation, their homeostasis is crucial for cell life. Members of the polyamine oxidase gene family have been identified in a wide variety of animals, including vertebrates, arthropodes, nematodes, placozoa, as well as in plants and fungi. Polyamine oxidases (PAOs) from yeast can oxidize spermine, N1-acetylspermine, and N1-acetylspermidine, however, in vertebrates two different enzymes, namely spermine oxidase (SMO) and acetylpolyamine oxidase (APAO), specifically catalyze the oxidation of spermine, and N1-acetylspermine/N1-acetylspermidine, respectively. Little is known about the molecular evolutionary history of these enzymes. However, since the yeast PAO is able to catalyze the oxidation of both acetylated and non acetylated polyamines, and in vertebrates these functions are addressed by two specialized polyamine oxidase subfamilies (APAO and SMO), it can be hypothesized an ancestral reference for the former enzyme from which the latter would have been derived. We analysed 36 SMO, 26 APAO, and 14 PAO homologue protein sequences from 54 taxa including various vertebrates and invertebrates. The analysis of the full-length sequences and the principal domains of vertebrate and invertebrate PAOs yielded consensus primary protein sequences for vertebrate SMOs and APAOs, and invertebrate PAOs. This analysis, coupled to molecular modeling techniques, also unveiled sequence regions that confer specific structural and functional properties, including substrate specificity, by the different PAO subfamilies. Molecular phylogenetic trees revealed a basal position of all the invertebrates PAO enzymes relative to vertebrate SMOs and APAOs. PAOs from insects constitute a monophyletic clade. Two PAO variants sampled in the amphioxus are basal to the dichotomy between two well supported monophyletic clades including, respectively, all the SMOs and APAOs from vertebrates. The two vertebrate monophyletic clades clustered strictly mirroring the organismal phylogeny of fishes, amphibians, reptiles, birds, and mammals. Evidences from comparative genomic analysis, structural evolution and functional divergence in a phylogenetic framework across Metazoa suggested an evolutionary scenario where the ancestor PAO coding sequence, present in invertebrates as an orthologous gene, has been duplicated in the vertebrate branch to originate the paralogous SMO and APAO genes. A further genome evolution event concerns the SMO gene of placental, but not marsupial and monotremate, mammals which increased its functional variation following an alternative splicing (AS) mechanism. In this study the explicit integration in a phylogenomic framework of phylogenetic tree construction, structure prediction, and biochemical function data/prediction, allowed inferring the molecular evolutionary history of the PAO gene family and to disambiguate paralogous genes related by duplication event (SMO and APAO) and orthologous genes related by speciation events (PAOs, SMOs/APAOs). Further, while in vertebrates experimental data corroborate SMO and APAO molecular function predictions, in invertebrates the finding of a supported phylogenetic clusters of insect PAOs and the co-occurrence of two PAO variants in the amphioxus urgently claim the need for future structure-function studies.
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Second medical opinions: the views of oncology patients and their physicians.
Philip, Jennifer; Gold, Michelle; Schwarz, Max; Komesaroff, Paul
2010-09-01
Second medical opinions (SMOs) are common in oncology practice, but the nature of these consultations has received relatively little attention. This study examines the views of patients with advanced cancer and their physicians of SMOs. Parallel, concurrent surveys were developed for patients and physicians. The first was distributed to outpatients with advanced cancer-attending specialist clinics in an Australian quaternary hospital. The second survey, developed on the basis of results of exploratory interviews with medical oncologists, was distributed to medical oncologists in Australia. Seventeen of fifty two (33%) patients had sought a SMO, most commonly prompted by concerns around communication with their first doctor, the extreme and desperate nature of their medical condition and the need for reassurance. Most (94%) patients found the SMO helpful, with satisfaction related to improved communication and reassurance. Patients were concerned that seeking a second medical opinion may affect their relationship with their primary doctor. Most physicians (82%) reported seeing between one and five SMO per month, with patients being motivated by the need for additional information and reassurance. Physicians regarded SMO patients as having greater information needs (84%), greater psychosocial needs (58%) and requiring more of the physician's time and energy (77%) than other patients. SMOs are common in cancer care with most patients motivated by the need for improved communication, additional information and reassurance. Physicians identify patients who seek SMOs as having additional psychosocial needs compared with other oncology patients.
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NASA Astrophysics Data System (ADS)
Kumar, Shani; Dhingra, Vishal; Garg, Amit; Chowdhuri, Arijit
2016-05-01
Worldwide researchers are actively engaged in utilizing Graphene and its related materials in gas sensing applications. A high surface-to-volume ratio that offers scope of optimization leading to enhanced sensing performance besides lower sensor operating temperatures are some advantages that graphene based sensors possess over conventional semiconducting metal oxide (SMO) sensors. Conventional SMO based gas sensors are known to suffer from problems of cross-selectivity where selectivity is understood to be a gas sensor's ability to preferentially detect one particular gas without responding to or experiencing interference from other gases present in the ambient. In the current study gas sensing mechanism of Graphene oxide (GO) thin films is investigated by repeatedly exposing the sensing configuration to various gases and its cross-selectivity response to the same is examined. In the investigation typical gas sensing response characteristics of the sensor configuration are studied in both oxidizing as well as reducing environments. The gas sensing data is acquired by means of Keithley 6487 picoammeter which is interfaced with a customized Gas Sensing Test Rig (GSTR) that provides a controlled ambient to the sensors for measurement of reproducible characteristics. GSTR further provided the option of varying the operating temperature and gas concentration for the different sensor configurations under study. XRD studies indicate formation of GO with typical crystallite size of 4.2 nm. UV-Vis investigations reveal a typical band-gap of 4.42 (eV) which is in conformity with those reported in the available literature.1,2
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Desouza, Lynette A; Sathanoori, Malini; Kapoor, Richa; Rajadhyaksha, Neha; Gonzalez, Luis E; Kottmann, Andreas H; Tole, Shubha; Vaidya, Vidita A
2011-05-01
Thyroid hormone is important for development and plasticity in the immature and adult mammalian brain. Several thyroid hormone-responsive genes are regulated during specific developmental time windows, with relatively few influenced across the lifespan. We provide novel evidence that thyroid hormone regulates expression of the key developmental morphogen sonic hedgehog (Shh), and its coreceptors patched (Ptc) and smoothened (Smo), in the early embryonic and adult forebrain. Maternal hypo- and hyperthyroidism bidirectionally influenced Shh mRNA in embryonic forebrain signaling centers at stages before fetal thyroid hormone synthesis. Further, Smo and Ptc expression were significantly decreased in the forebrain of embryos derived from hypothyroid dams. Adult-onset thyroid hormone perturbations also regulated expression of the Shh pathway bidirectionally, with a significant induction of Shh, Ptc, and Smo after hyperthyroidism and a decline in Smo expression in the hypothyroid brain. Short-term T₃ administration resulted in a significant induction of cortical Shh mRNA expression and also enhanced reporter gene expression in Shh(+/LacZ) mice. Further, acute T₃ treatment of cortical neuronal cultures resulted in a rapid and significant increase in Shh mRNA, suggesting direct effects. Chromatin immunoprecipitation assays performed on adult neocortex indicated enhanced histone acetylation at the Shh promoter after acute T₃ administration, providing further support that Shh is a thyroid hormone-responsive gene. Our results indicate that maternal and adult-onset perturbations of euthyroid status cause robust and region-specific changes in the Shh pathway in the embryonic and adult forebrain, implicating Shh as a possible mechanistic link for specific neurodevelopmental effects of thyroid hormone.
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Current twin studies in Germany: report on CoSMoS, SOEP, and ChronoS.
Hahn, Elisabeth; Gottschling, Juliana; Spinath, Frank M
2013-02-01
This article summarizes the status of three recent German twin studies: CoSMoS, SOEP, and ChronoS. The German twin study on Cognitive Ability, Self-Reported Motivation, and School Achievement (CoSMoS) is a three-wave longitudinal study of monozygotic and dizygotic twins reared together, and aims to investigate predictors of and influences on school performance. In the first wave of the data collection in 2005, 408 pairs of twins aged between 7 and 11 as well as their parents participated in CoSMoS. The SOEP twin study is an extended twin study, which has combined data from monozygotic and dizygotic twins reared together with additional data from full sibling pairs, mother-child, and grandparent-child dyads who participated in the German Socio-Economic Panel (GSOEP) study. The SOEP twin project comprises about 350 twin and 950 non-twin pairs aged between 17 and 70. Data were collected between 2009 and 2010, with a focus on personality traits, wellbeing, education, employment, income, living situation, life-satisfaction, and several attitudes. The aim of the Chronotype twin study (ChronoS) was to examine genetic and environmental influences on chronotype (morningness and eveningness), coping strategies, and several aspects of the previous SOEP twin project in a sample of 301 twin pairs aged between 19 and 76 years, recruited in 2010 and 2011. Part of the ChronoS twin sample also participated in the earlier SOEP twin study, representing a second wave of assessments. We briefly describe the design and contents of these three studies as well as selected recent findings.
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O'Neill, Andrea; Erikson, Li; Barnard, Patrick; Limber, Patrick; Vitousek, Sean; Warrick, Jonathan; Foxgrover, Amy C.; Lovering, Jessica
2018-01-01
Due to the effects of climate change over the course of the next century, the combination of rising sea levels, severe storms, and coastal change will threaten the sustainability of coastal communities, development, and ecosystems as we know them today. To clearly identify coastal vulnerabilities and develop appropriate adaptation strategies due to projected increased levels of coastal flooding and erosion, coastal managers need local-scale hazards projections using the best available climate and coastal science. In collaboration with leading scientists world-wide, the USGS designed the Coastal Storm Modeling System (CoSMoS) to assess the coastal impacts of climate change for the California coast, including the combination of sea-level rise, storms, and coastal change. In this project, we directly address the needs of coastal resource managers in Southern California by integrating a vast range of global climate change projections in a thorough and comprehensive numerical modeling framework. In Part 1 of a two-part submission on CoSMoS, methods and the latest improvements are discussed, and an example of hazard projections is presented.
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Metabolites in vertebrate Hedgehog signaling.
Roberg-Larsen, Hanne; Strand, Martin Frank; Krauss, Stefan; Wilson, Steven Ray
2014-04-11
The Hedgehog (HH) signaling pathway is critical in embryonic development, stem cell biology, tissue homeostasis, chemoattraction and synapse formation. Irregular HH signaling is associated with a number of disease conditions including congenital disorders and cancer. In particular, deregulation of HH signaling has been linked to skin, brain, lung, colon and pancreatic cancers. Key mediators of the HH signaling pathway are the 12-pass membrane protein Patched (PTC), the 7-pass membrane protein Smoothened (SMO) and the GLI transcription factors. PTC shares homology with the RND family of small-molecule transporters and it has been proposed that it interferes with SMO through metabolites. Although a conclusive picture is lacking, substantial efforts are made to identify and understand natural metabolites/sterols, including cholesterol, vitamin D3, oxysterols and glucocorticoides, that may be affected by, or influence the HH signaling cascade at the level of PTC and SMO. In this review we will elaborate the role of metabolites in HH signaling with a focus on oxysterols, and discuss advancements in modern analytical approaches in the field. Copyright © 2014 Elsevier Inc. All rights reserved.
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Choi, Hyunjung; Shin, Ji Hyun; Kim, Eun Sung; Park, So Jung; Bae, Il-Hong; Jo, Yoon Kyung; Jeong, In Young; Kim, Hyoung-June; Lee, Youngjin; Park, Hea Chul; Jeon, Hong Bae; Kim, Ki Woo; Lee, Tae Ryong; Cho, Dong-Hyung
2016-01-01
The primary cilium is an organelle protruding from the cell body that senses external stimuli including chemical, mechanical, light, osmotic, fluid flow, and gravitational signals. Skin is always exposed to the external environment and responds to external stimuli. Therefore, it is possible that primary cilia have an important role in skin. Ciliogenesis was reported to be involved in developmental processes in skin, such as keratinocyte differentiation and hair formation. However, the relation between skin pigmentation and primary cilia is largely unknown. Here, we observed that increased melanogenesis in melanocytes treated with a melanogenic inducer was inhibited by a ciliogenesis inducer, cytochalasin D, and serum-free culture. However, these inhibitory effects disappeared in GLI2 knockdown cells. In addition, activation of sonic hedgehog (SHH)-smoothened (Smo) signaling pathway by a Smo agonist, SAG inhibited melanin synthesis in melanocytes and pigmentation in a human skin model. On the contrary, an inhibitor of primary cilium formation, ciliobrevin A1, activated melanogenesis in melanocytes. These results suggest that skin pigmentation may be regulated partly by the induction of ciliogenesis through Smo-GLI2 signaling.
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Program and Project Management Framework
NASA Technical Reports Server (NTRS)
Butler, Cassandra D.
2002-01-01
The primary objective of this project was to develop a framework and system architecture for integrating program and project management tools that may be applied consistently throughout Kennedy Space Center (KSC) to optimize planning, cost estimating, risk management, and project control. Project management methodology used in building interactive systems to accommodate the needs of the project managers is applied as a key component in assessing the usefulness and applicability of the framework and tools developed. Research for the project included investigation and analysis of industrial practices, KSC standards, policies, and techniques, Systems Management Office (SMO) personnel, and other documented experiences of project management experts. In addition, this project documents best practices derived from the literature as well as new or developing project management models, practices, and techniques.
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Underwater acoustic positioning system for the SMO and KM3NeT - Italia projects
DOE Office of Scientific and Technical Information (OSTI.GOV)
Viola, S.; Barbagallo, G.; Cacopardo, G.
In the underwater neutrino telescopes, the positions of the Cherenkov light sensors and their movements must be known with an accuracy of few tens of centimetres. In this work, the activities of the SMO and KM3NeT-Italia teams for the development of an acoustic positioning system for KM3NeT-Italia project are presented. The KM3NeT-Italia project foresees the construction, within two years, of 8 towers in the view of the several km{sup 3}-scale neutrino telescope KM3NeT.
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Torija, Antonio J; Ruiz, Diego P
2015-02-01
The prediction of environmental noise in urban environments requires the solution of a complex and non-linear problem, since there are complex relationships among the multitude of variables involved in the characterization and modelling of environmental noise and environmental-noise magnitudes. Moreover, the inclusion of the great spatial heterogeneity characteristic of urban environments seems to be essential in order to achieve an accurate environmental-noise prediction in cities. This problem is addressed in this paper, where a procedure based on feature-selection techniques and machine-learning regression methods is proposed and applied to this environmental problem. Three machine-learning regression methods, which are considered very robust in solving non-linear problems, are used to estimate the energy-equivalent sound-pressure level descriptor (LAeq). These three methods are: (i) multilayer perceptron (MLP), (ii) sequential minimal optimisation (SMO), and (iii) Gaussian processes for regression (GPR). In addition, because of the high number of input variables involved in environmental-noise modelling and estimation in urban environments, which make LAeq prediction models quite complex and costly in terms of time and resources for application to real situations, three different techniques are used to approach feature selection or data reduction. The feature-selection techniques used are: (i) correlation-based feature-subset selection (CFS), (ii) wrapper for feature-subset selection (WFS), and the data reduction technique is principal-component analysis (PCA). The subsequent analysis leads to a proposal of different schemes, depending on the needs regarding data collection and accuracy. The use of WFS as the feature-selection technique with the implementation of SMO or GPR as regression algorithm provides the best LAeq estimation (R(2)=0.94 and mean absolute error (MAE)=1.14-1.16 dB(A)). Copyright © 2014 Elsevier B.V. All rights reserved.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Johnson, H.C.
1998-07-01
The Idaho National Engineering and Environmental Laboratory (INEEL) has several permitted treatment, storage and disposal facilities. The INEEL Sample Management Office (SMO) conducts all analysis subcontracting activities for Department of Energy Environmental Management programs at the INEEL. In this role, the INEEL SMO has had the opportunity to subcontract the analyses of various wastes (including ash from an interim status incinerator) requesting a target analyte list equivalent to the constituents listed in 40 Code of Federal Regulations. These analyses are required to ensure that treated wastes do not contain underlying hazardous constituents (UHC) at concentrations greater than the universal treatmentmore » standards (UTS) prior to land disposal. The INEEL SMO has conducted a good-faith effort by negotiating with several commercial laboratories to identify the lowest possible quantitation and detection limits that can be achieved for the organic UHC analytes. The results of this negotiating effort has been the discovery that no single laboratory (currently under subcontract with the INEEL SMO) can achieve a detection level that is within an order of magnitude of the UTS for all organic parameters on a clean sample matrix (e.g., sand). This does not mean that there is no laboratory that can achieve the order of magnitude requirements for all organic UHCs on a clean sample matrix. The negotiations held to date indicate that it is likely that no laboratory can achieve the order of magnitude requirements for a difficult sample matrix (e.g., an incinerator ash). The authors suggest that the regulation needs to be revised to address the disparity between what is achievable in the laboratory and the regulatory levels required by the UTS.« less
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Barnard, Patrick; Maarten van Ormondt,; Erikson, Li H.; Jodi Eshleman,; Hapke, Cheryl J.; Peter Ruggiero,; Peter Adams,; Foxgrover, Amy C.
2014-01-01
The Coastal Storm Modeling System (CoSMoS) applies a predominantly deterministic framework to make detailed predictions (meter scale) of storm-induced coastal flooding, erosion, and cliff failures over large geographic scales (100s of kilometers). CoSMoS was developed for hindcast studies, operational applications (i.e., nowcasts and multiday forecasts), and future climate scenarios (i.e., sea-level rise + storms) to provide emergency responders and coastal planners with critical storm hazards information that may be used to increase public safety, mitigate physical damages, and more effectively manage and allocate resources within complex coastal settings. The prototype system, developed for the California coast, uses the global WAVEWATCH III wave model, the TOPEX/Poseidon satellite altimetry-based global tide model, and atmospheric-forcing data from either the US National Weather Service (operational mode) or Global Climate Models (future climate mode), to determine regional wave and water-level boundary conditions. These physical processes are dynamically downscaled using a series of nested Delft3D-WAVE (SWAN) and Delft3D-FLOW (FLOW) models and linked at the coast to tightly spaced XBeach (eXtreme Beach) cross-shore profile models and a Bayesian probabilistic cliff failure model. Hindcast testing demonstrates that, despite uncertainties in preexisting beach morphology over the ~500 km alongshore extent of the pilot study area, CoSMoS effectively identifies discrete sections of the coast (100s of meters) that are vulnerable to coastal hazards under a range of current and future oceanographic forcing conditions, and is therefore an effective tool for operational and future climate scenario planning.
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Robinson, Giles W.; Orr, Brent A.; Wu, Gang; Gururangan, Sridharan; Lin, Tong; Qaddoumi, Ibrahim; Packer, Roger J.; Goldman, Stewart; Prados, Michael D.; Desjardins, Annick; Chintagumpala, Murali; Takebe, Naoko; Kaste, Sue C.; Rusch, Michael; Allen, Sariah J.; Onar-Thomas, Arzu; Stewart, Clinton F.; Fouladi, Maryam; Boyett, James M.; Gilbertson, Richard J.; Curran, Tom; Ellison, David W.; Gajjar, Amar
2015-01-01
Purpose Two phase II studies assessed the efficacy of vismodegib, a sonic hedgehog (SHH) pathway inhibitor that binds smoothened (SMO), in pediatric and adult recurrent medulloblastoma (MB). Patients and Methods Adult patients enrolled onto PBTC-025B and pediatric patients enrolled onto PBTC-032 were treated with vismodegib (150 to 300 mg/d). Protocol-defined response, which had to be sustained for 8 weeks, was confirmed by central neuroimaging review. Molecular tests to identify patterns of response and insensitivity were performed when tissue was available. Results A total of 31 patients were enrolled onto PBTC-025B, and 12 were enrolled onto PBTC-032. Three patients in PBTC-025B and one in PBTC-032, all with SHH-subgroup MB (SHH-MB), exhibited protocol-defined responses. Progression-free survival (PFS) was longer in those with SHH-MB than in those with non-SHH–MB, and prolonged disease stabilization occurred in 41% of patient cases of SHH-MB. Among those with SHH-MB, loss of heterozygosity of PTCH1 was associated with prolonged PFS, and diffuse staining of P53 was associated with reduced PFS. Whole-exome sequencing identified mutations in SHH genes downstream from SMO in four of four tissue samples from nonresponders and upstream of SMO in two of four patients with favorable responses. Conclusion Vismodegib exhibits activity against adult recurrent SHH-MB but not against recurrent non-SHH–MB. Inadequate accrual of pediatric patients precluded conclusions in this population. Molecular analyses support the hypothesis that SMO inhibitor activity depends on the genomic aberrations within the tumor. Such inhibitors should be advanced in SHH-MB studies; however, molecular and genomic work remains imperative to identify target populations that will truly benefit. PMID:26169613
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Tirnitz-Parker, Janina Elke Eleonore; Hamson, Elizabeth Jane; Warren, Alessandra; Maneck, Bharvi; Chen, Jinbiao; Patkunanathan, Bramilla; Boland, Jade; Cheng, Robert; Shackel, Nicholas Adam; Seth, Devanshi; Bowen, David Geoffrey; Martelotto, Luciano Gastón; Watkins, D. Neil; McCaughan, Geoffrey William
2017-01-01
Canonical Hedgehog (Hh) signaling in vertebrate cells occurs following Smoothened activation/translocation into the primary cilia (Pc), followed by a GLI transcriptional response. Nonetheless, GLI activation can occur independently of the canonical Hh pathway. Using a murine model of liver injury, we previously identified the importance of canonical Hh signaling within the Pc+ liver progenitor cell (LPC) population and noted that SMO-independent, GLI-mediated signals were important in multiple Pc-ve GLI2+ intrahepatic populations. This study extends these observations to human liver tissue, and analyses the effect of GLI inhibition on LPC viability/gene expression. Human donor and cirrhotic liver tissue specimens were evaluated for SHH, GLI2 and Pc expression using immunofluorescence and qRT-PCR. Changes to viability and gene expression in LPCs in vitro were assessed following GLI inhibition. Identification of Pc (as a marker of canonical Hh signaling) in human cirrhosis was predominantly confined to the ductular reaction and LPCs. In contrast, GLI2 was expressed in multiple cell populations including Pc-ve endothelium, hepatocytes, and leukocytes. HSCs/myofibroblasts (>99%) expressed GLI2, with only 1.92% displaying Pc. In vitro GLI signals maintained proliferation/viability within LPCs and GLI inhibition affected the expression of genes related to stemness, hepatocyte/biliary differentiation and Hh/Wnt signaling. At least two mechanisms of GLI signaling (Pc/SMO-dependent and Pc/SMO-independent) mediate chronic liver disease pathogenesis. This may have significant ramifications for the choice of Hh inhibitor (anti-SMO or anti-GLI) suitable for clinical trials. We also postulate GLI delivers a pro-survival signal to LPCs whilst maintaining stemness. PMID:28187190
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Grzelak, Candice Alexandra; Sigglekow, Nicholas David; Tirnitz-Parker, Janina Elke Eleonore; Hamson, Elizabeth Jane; Warren, Alessandra; Maneck, Bharvi; Chen, Jinbiao; Patkunanathan, Bramilla; Boland, Jade; Cheng, Robert; Shackel, Nicholas Adam; Seth, Devanshi; Bowen, David Geoffrey; Martelotto, Luciano Gastón; Watkins, D Neil; McCaughan, Geoffrey William
2017-01-01
Canonical Hedgehog (Hh) signaling in vertebrate cells occurs following Smoothened activation/translocation into the primary cilia (Pc), followed by a GLI transcriptional response. Nonetheless, GLI activation can occur independently of the canonical Hh pathway. Using a murine model of liver injury, we previously identified the importance of canonical Hh signaling within the Pc+ liver progenitor cell (LPC) population and noted that SMO-independent, GLI-mediated signals were important in multiple Pc-ve GLI2+ intrahepatic populations. This study extends these observations to human liver tissue, and analyses the effect of GLI inhibition on LPC viability/gene expression. Human donor and cirrhotic liver tissue specimens were evaluated for SHH, GLI2 and Pc expression using immunofluorescence and qRT-PCR. Changes to viability and gene expression in LPCs in vitro were assessed following GLI inhibition. Identification of Pc (as a marker of canonical Hh signaling) in human cirrhosis was predominantly confined to the ductular reaction and LPCs. In contrast, GLI2 was expressed in multiple cell populations including Pc-ve endothelium, hepatocytes, and leukocytes. HSCs/myofibroblasts (>99%) expressed GLI2, with only 1.92% displaying Pc. In vitro GLI signals maintained proliferation/viability within LPCs and GLI inhibition affected the expression of genes related to stemness, hepatocyte/biliary differentiation and Hh/Wnt signaling. At least two mechanisms of GLI signaling (Pc/SMO-dependent and Pc/SMO-independent) mediate chronic liver disease pathogenesis. This may have significant ramifications for the choice of Hh inhibitor (anti-SMO or anti-GLI) suitable for clinical trials. We also postulate GLI delivers a pro-survival signal to LPCs whilst maintaining stemness.
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Desouza, Lynette A.; Sathanoori, Malini; Kapoor, Richa; Rajadhyaksha, Neha; Gonzalez, Luis E.; Kottmann, Andreas H.; Tole, Shubha
2011-01-01
Thyroid hormone is important for development and plasticity in the immature and adult mammalian brain. Several thyroid hormone-responsive genes are regulated during specific developmental time windows, with relatively few influenced across the lifespan. We provide novel evidence that thyroid hormone regulates expression of the key developmental morphogen sonic hedgehog (Shh), and its coreceptors patched (Ptc) and smoothened (Smo), in the early embryonic and adult forebrain. Maternal hypo- and hyperthyroidism bidirectionally influenced Shh mRNA in embryonic forebrain signaling centers at stages before fetal thyroid hormone synthesis. Further, Smo and Ptc expression were significantly decreased in the forebrain of embryos derived from hypothyroid dams. Adult-onset thyroid hormone perturbations also regulated expression of the Shh pathway bidirectionally, with a significant induction of Shh, Ptc, and Smo after hyperthyroidism and a decline in Smo expression in the hypothyroid brain. Short-term T3 administration resulted in a significant induction of cortical Shh mRNA expression and also enhanced reporter gene expression in Shh+/LacZ mice. Further, acute T3 treatment of cortical neuronal cultures resulted in a rapid and significant increase in Shh mRNA, suggesting direct effects. Chromatin immunoprecipitation assays performed on adult neocortex indicated enhanced histone acetylation at the Shh promoter after acute T3 administration, providing further support that Shh is a thyroid hormone-responsive gene. Our results indicate that maternal and adult-onset perturbations of euthyroid status cause robust and region-specific changes in the Shh pathway in the embryonic and adult forebrain, implicating Shh as a possible mechanistic link for specific neurodevelopmental effects of thyroid hormone. PMID:21363934
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Overactivation of hedgehog signaling alters development of the ovarian vasculature in mice.
Ren, Yi; Cowan, Robert G; Migone, Fernando F; Quirk, Susan M
2012-06-01
The hedgehog (HH) signaling pathway is critical for ovarian function in Drosophila, but its role in the mammalian ovary has not been defined. Previously, expression of a dominant active allele of the HH signal transducer protein smoothened (SMO) in Amhr2(cre/+)SmoM2 mice caused anovulation in association with a lack of smooth muscle in the theca of developing follicles. The current study examined events during the first 2 wk of life in Amhr2(cre/+)SmoM2 mice to gain insight into the cause of anovulation. Expression of transcriptional targets of HH signaling, Gli1, Ptch1, and Hhip, which are used as measures of pathway activity, were elevated during the first several days of life in Amhr2(cre/+)SmoM2 mice compared to controls but were similar to controls in older mice. Microarray analysis showed that genes with increased expression in 2-day-old mutants compared to controls were enriched for the processes of vascular and tube development and steroidogenesis. The density of platelet endothelial cell adhesion molecule (PECAM)-labeled endothelial tubes was increased in the cortex of newborn ovaries of mutant mice. Costaining of preovulatory follicles for PECAM and smooth muscle actin showed that muscle-type vascular support cells are deficient in theca of mutant mice. Expression of genes for steroidogenic enzymes that are normally expressed in the fetal adrenal gland were elevated in newborn ovaries of mutant mice. In summary, overactivation of HH signaling during early life alters gene expression and vascular development and this is associated with the lifelong development of anovulatory follicles in which the thecal vasculature fails to mature appropriately.
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Overactivation of Hedgehog Signaling Alters Development of the Ovarian Vasculature in Mice1
Ren, Yi; Cowan, Robert G.; Migone, Fernando F.; Quirk, Susan M.
2012-01-01
ABSTRACT The hedgehog (HH) signaling pathway is critical for ovarian function in Drosophila, but its role in the mammalian ovary has not been defined. Previously, expression of a dominant active allele of the HH signal transducer protein smoothened (SMO) in Amhr2cre/+SmoM2 mice caused anovulation in association with a lack of smooth muscle in the theca of developing follicles. The current study examined events during the first 2 wk of life in Amhr2cre/+SmoM2 mice to gain insight into the cause of anovulation. Expression of transcriptional targets of HH signaling, Gli1, Ptch1, and Hhip, which are used as measures of pathway activity, were elevated during the first several days of life in Amhr2cre/+SmoM2 mice compared to controls but were similar to controls in older mice. Microarray analysis showed that genes with increased expression in 2-day-old mutants compared to controls were enriched for the processes of vascular and tube development and steroidogenesis. The density of platelet endothelial cell adhesion molecule (PECAM)-labeled endothelial tubes was increased in the cortex of newborn ovaries of mutant mice. Costaining of preovulatory follicles for PECAM and smooth muscle actin showed that muscle-type vascular support cells are deficient in theca of mutant mice. Expression of genes for steroidogenic enzymes that are normally expressed in the fetal adrenal gland were elevated in newborn ovaries of mutant mice. In summary, overactivation of HH signaling during early life alters gene expression and vascular development and this is associated with the lifelong development of anovulatory follicles in which the thecal vasculature fails to mature appropriately. PMID:22402963
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Transcriptional profiles of SHH pathway genes in keratocystic odontogenic tumor and ameloblastoma.
Gurgel, Clarissa Araújo Silva; Buim, Marcilei Eliza Cavichiolli; Carvalho, Kátia Cândido; Sales, Caroline Brandi Schlaepfer; Reis, Mitermayer Galvão; de Souza, Renata Oliveira; de Faro Valverde, Ludmila; de Azevedo, Roberto Almeida; Dos Santos, Jean Nunes; Soares, Fernando Augusto; Ramos, Eduardo Antônio Gonçalves
2014-09-01
Sonic hedgehog (SHH) pathway activation has been identified as a key factor in the development of many types of tumors, including odontogenic tumors. Our study examined the expression of genes in the SHH pathway to characterize their roles in the pathogenesis of keratocystic odontogenic tumors (KOT) and ameloblastomas (AB). We quantified the expression of SHH, SMO, PTCH1, SUFU, GLI1, CCND1, and BCL2 genes by qPCR in a total of 23 KOT, 11 AB, and three non-neoplastic oral mucosa (NNM). We also measured the expression of proteins related to this pathway (CCND1 and BCL2) by immunohistochemistry. We observed overexpression of SMO, PTCH1, GLI1, and CCND1 genes in both KOT (23/23) and AB (11/11). However, we did not detect expression of the SHH gene in 21/23 KOT and 10/11 AB tumors. Low levels of the SUFU gene were expressed in KOT (P = 0.0199) and AB (P = 0.0127) relative to the NNM. Recurrent KOT exhibited high levels of SMO (P = 0.035), PTCH1 (P = 0.048), CCND1 (P = 0.048), and BCL2 (P = 0.045) transcripts. Using immunolabeling of CCND1, we observed no statistical difference between primary and recurrent KOT (P = 0.8815), sporadic and NBCCS-KOT (P = 0.7688), and unicystic and solid AB (P = 0.7521). Overexpression of upstream (PTCH1 and SMO) and downstream (GLI1, CCND1 and BCL2) genes in the SHH pathway leads to the constitutive activation of this pathway in KOT and AB and may suggest a mechanism for the development of these types of tumors. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
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de Oliveira, Gustavo Vieira; Nascimento, Luiz; Volino-Souza, Mônica; Mesquita, Jacilene; Alvares, Thiago
2018-03-22
The ergogenic effect of beetroot on the exercise performance of trained cyclists, runners, kayakers, and swimmers has been demonstrated. However, whether or not beetroot supplementation presents a beneficial effect on the exercise performance of jiu-jitsu athletes (JJA) remains inconclusive. Therefore, present study assessed the effect of beetroot-based gel (BG) supplementation on maximal voluntary contraction (MVC), exercise time until fatigue (ETF), muscle O2 saturation (SmO2), blood volume (tHb), and plasma nitrate and lactate in response to handgrip isotonic exercise (HIE) in JJA. In a randomized, crossover, double-blind design, 12 JJA performed three sets of HIE at 40% of the MVC until fatigue after 8 days (8th dose was offered 120 min previous exercise) of BG supplementation or a nitrate-depleted gel (PLA), and forearm SmO2 and tHb were continuously monitored by using near-infrared spectroscopy. Blood samples were taken before, immediately after exercise, and 20 min after exercise recovery in PLA and BG condition. MVC was evaluated at baseline and 20 min after HIE. There was a significant reduction in ∆MVC decline after HIE in BG condition. Forearm SmO2 during exercise recovery was significantly greater only after BG supplementation. No significant difference in ETF and tHb were observed between both BG and PLA in response to HIE. Plasma nitrate increased only after BG, whereas the exercise-induced increase in plasma lactate was significantly lower in BG when compared to PLA. In conclusion, BG supplementation may be a good nutritional strategy to improve forearm SmO2 and prevent force decline in response to exercise in JJA.
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Sensorless sliding mode observer for a five-phase permanent magnet synchronous motor drive.
Hosseyni, Anissa; Trabelsi, Ramzi; Mimouni, Med Faouzi; Iqbal, Atif; Alammari, Rashid
2015-09-01
This paper deals with the sensorless vector controlled five-phase permanent magnet synchronous motor (PMSM) drive based on a sliding mode observer (SMO). The observer is designed considering the back electromotive force (EMF) of five-phase permanent magnet synchronous motor. The SMO structure and design are illustrated. Stability of the proposed observer is demonstrated using Lyapunov stability criteria. The proposed strategy is asymptotically stable in the context of Lyapunov theory. Simulated results on a five-phase PMSM drive are displayed to validate the feasibility and the effectiveness of the proposed control strategy. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.
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Robust In-Flight Sensor Fault Diagnostics for Aircraft Engine Based on Sliding Mode Observers
Chang, Xiaodong; Huang, Jinquan; Lu, Feng
2017-01-01
For a sensor fault diagnostic system of aircraft engines, the health performance degradation is an inevitable interference that cannot be neglected. To address this issue, this paper investigates an integrated on-line sensor fault diagnostic scheme for a commercial aircraft engine based on a sliding mode observer (SMO). In this approach, one sliding mode observer is designed for engine health performance tracking, and another for sensor fault reconstruction. Both observers are employed in in-flight applications. The results of the former SMO are analyzed for post-flight updating the baseline model of the latter. This idea is practical and feasible since the updating process does not require the algorithm to be regulated or redesigned, so that ground-based intervention is avoided, and the update process is implemented in an economical and efficient way. With this setup, the robustness of the proposed scheme to the health degradation is much enhanced and the latter SMO is able to fulfill sensor fault reconstruction over the course of the engine life. The proposed sensor fault diagnostic system is applied to a nonlinear simulation of a commercial aircraft engine, and its effectiveness is evaluated in several fault scenarios. PMID:28398255
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Robust In-Flight Sensor Fault Diagnostics for Aircraft Engine Based on Sliding Mode Observers.
Chang, Xiaodong; Huang, Jinquan; Lu, Feng
2017-04-11
For a sensor fault diagnostic system of aircraft engines, the health performance degradation is an inevitable interference that cannot be neglected. To address this issue, this paper investigates an integrated on-line sensor fault diagnostic scheme for a commercial aircraft engine based on a sliding mode observer (SMO). In this approach, one sliding mode observer is designed for engine health performance tracking, and another for sensor fault reconstruction. Both observers are employed in in-flight applications. The results of the former SMO are analyzed for post-flight updating the baseline model of the latter. This idea is practical and feasible since the updating process does not require the algorithm to be regulated or redesigned, so that ground-based intervention is avoided, and the update process is implemented in an economical and efficient way. With this setup, the robustness of the proposed scheme to the health degradation is much enhanced and the latter SMO is able to fulfill sensor fault reconstruction over the course of the engine life. The proposed sensor fault diagnostic system is applied to a nonlinear simulation of a commercial aircraft engine, and its effectiveness is evaluated in several fault scenarios.
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Borges, Paulo A. V.; Guerreiro, Orlando; Ferreira, Maria T.; Borges, Annabella; Ferreira, Filomena; Bicudo, Nuno; Nunes, Lina; Marcos, Rita S.; Arroz, Ana M.; Scheffrahn, Rudolf H.; Myles, Timothy G.
2014-01-01
Abstract The dispersal flights of West Indian drywood termite, Cryptotermes brevis (Walker) (Isoptera: Kalotermitidae) were surveyed in the major cities of Azores. The sampling device used to estimate termite density consisted of a yellow adhesive trap (size 45 by 24 cm), placed with an artificial or natural light source in a dark attic environment. In addition, data from two other projects were used to improve the knowledge about the geographical distribution of the species. The level of infestation in the two main Azorean towns differed, with high levels in the houses of Angra do Heroísmo, whereas in Ponta Delgada, there are fewer houses with high levels of infestation. The infestation in Ponta Delgada shows a pattern of spreading from the center outward to the city’s periphery, whereas in Angra do Heroísmo, there was a pattern of spreading outward from several foci. The heavy infestation observed in Angra do Heroísmo and the clear increase of infestation levels observed from 2010 to 2011 is a reason for concern and calls for an urgent application of an Integrated Pest Management (IPM) control strategy. PMID:25368085
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A semantic web ontology for small molecules and their biological targets.
Choi, Jooyoung; Davis, Melissa J; Newman, Andrew F; Ragan, Mark A
2010-05-24
A wide range of data on sequences, structures, pathways, and networks of genes and gene products is available for hypothesis testing and discovery in biological and biomedical research. However, data describing the physical, chemical, and biological properties of small molecules have not been well-integrated with these resources. Semantically rich representations of chemical data, combined with Semantic Web technologies, have the potential to enable the integration of small molecule and biomolecular data resources, expanding the scope and power of biomedical and pharmacological research. We employed the Semantic Web technologies Resource Description Framework (RDF) and Web Ontology Language (OWL) to generate a Small Molecule Ontology (SMO) that represents concepts and provides unique identifiers for biologically relevant properties of small molecules and their interactions with biomolecules, such as proteins. We instanced SMO using data from three public data sources, i.e., DrugBank, PubChem and UniProt, and converted to RDF triples. Evaluation of SMO by use of predetermined competency questions implemented as SPARQL queries demonstrated that data from chemical and biomolecular data sources were effectively represented and that useful knowledge can be extracted. These results illustrate the potential of Semantic Web technologies in chemical, biological, and pharmacological research and in drug discovery.
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Ground-based FTIR retrievals of SF6 on Reunion Island
NASA Astrophysics Data System (ADS)
Zhou, Minqiang; Langerock, Bavo; Vigouroux, Corinne; Wang, Pucai; Hermans, Christian; Stiller, Gabriele; Walker, Kaley A.; Dutton, Geoff; Mahieu, Emmanuel; De Mazière, Martine
2018-02-01
SF6 total columns were successfully retrieved from FTIR (Fourier transform infrared) measurements (Saint Denis and Maïdo) on Reunion Island (21° S, 55° E) between 2004 and 2016 using the SFIT4 algorithm: the retrieval strategy and the error budget were presented. The FTIR SF6 retrieval has independent information in only one individual layer, covering the whole of the troposphere and the lower stratosphere. The trend in SF6 was analysed based on the FTIR-retrieved dry-air column-averaged mole fractions (XSF6) on Reunion Island, the in situ measurements at America Samoa (SMO) and the collocated satellite measurements (Michelson Interferometer for Passive Atmospheric Sounding, MIPAS, and Atmospheric Chemistry Experiment Fourier Transform Spectrometer, ACE-FTS) in the southern tropics. The SF6 annual growth rate from FTIR retrievals is 0.265 ± 0.013 pptv year-1 for 2004-2016, which is slightly weaker than that from the SMO in situ measurements (0.285 ± 0.002 pptv year-1) for the same time period. The SF6 trend in the troposphere from MIPAS and ACE-FTS observations is also close to the ones from the FTIR retrievals and the SMO in situ measurements.
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Effects of annealing temperature on the H2-sensing properties of Pd-decorated WO3 nanorods
NASA Astrophysics Data System (ADS)
Lee, Sangmin; Lee, Woo Seok; Lee, Jae Kyung; Hyun, Soong Keun; Lee, Chongmu; Choi, Seungbok
2018-03-01
The temperature of the post-annealing treatment carried out after noble metal deposition onto semiconducting metal oxides (SMOs) must be carefully optimized to maximize the sensing performance of the metal-decorated SMO sensors. WO3 nanorods were synthesized by thermal evaporation of WO3 powders and decorated with Pd nanoparticles using a sol-gel method, followed by an annealing process. The effects of the annealing temperature on the hydrogen gas-sensing properties of the Pd-decorated WO3 nanorods were then examined; the optimal annealing temperature, leading to the highest response of the WO3 nanorod sensor to H2, was determined to be 600 °C. Post-annealing at 600 °C resulted in nanorods with the highest surface area-to-volume ratio, as well as in the optimal size and the largest number of deposited Pd nanoparticles, leading to the highest response and the shortest response/recovery times toward H2. The improved H2-sensing performance of the Pd-decorated WO3 nanorod sensor, compared to a sensor based on pristine WO3 nanorods, is attributed to the enhanced catalytic activity, increased surface area-to-volume ratio, and higher amounts of surface defects.
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NASA Astrophysics Data System (ADS)
Ishii, Masashi; Crowe, Iain F.; Halsall, Matthew P.; Hamilton, Bruce; Hu, Yongfeng; Sham, Tsun-Kong; Harako, Susumu; Zhao, Xin-Wei; Komuro, Shuji
2013-10-01
The local structure of luminescent Sm dopants was investigated using an X-ray absorption fine-structure technique with X-ray-excited optical luminescence. Because this technique evaluates X-ray absorption from luminescence, only optically active sites are analyzed. The Sm L3 near-edge spectrum contains split 5d states and a shake-up transition that are specific to luminescent Sm. Theoretical calculations using cluster models identified an atomic-scale distortion that can reproduce the split 5d states. The model with C4v local symmetry and compressive bond length of Sm-O of a six-fold oxygen (SmO6) cluster is most consistent with the experimental results.
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Noncanonical Hedgehog Signaling
Brennan, Donna; Chen, Xiaole; Cheng, Lan; Mahoney, My; Riobo, Natalia A.
2012-01-01
The notion of noncanonical hedgehog (Hh) signaling in mammals has started to receive support from numerous observations. By noncanonical, we refer to all those cellular and tissue responses to any of the Hh isoforms that are independent of transcriptional changes mediated by the Gli family of transcription factors. In this chapter, we discuss the most recent findings that suggest that Patched1 can regulate cell proliferation and apoptosis independently of Smoothened (Smo) and Gli and the reports that Smo modulates actin cytoskeleton-dependent processes such as fibroblast migration, endothelial cell tubulogenesis, axonal extension, and neurite formation by diverse mechanisms that exclude any involvement of Gli-dependent transcription. We also acknowledge the existence of less stronger evidence of noncanonical signaling in Drosophila. PMID:22391299
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Semiconductor metal oxide compounds based gas sensors: A literature review
NASA Astrophysics Data System (ADS)
Patil, Sunil Jagannath; Patil, Arun Vithal; Dighavkar, Chandrakant Govindrao; Thakare, Kashinath Shravan; Borase, Ratan Yadav; Nandre, Sachin Jayaram; Deshpande, Nishad Gopal; Ahire, Rajendra Ramdas
2015-03-01
This paper gives a statistical view about important contributions and advances on semiconductor metal oxide (SMO) compounds based gas sensors developed to detect the air pollutants such as liquefied petroleum gas (LPG), H2S, NH3, CO2, acetone, ethanol, other volatile compounds and hazardous gases. Moreover, it is revealed that the alloy/composite made up of SMO gas sensors show better gas response than their counterpart single component gas sensors, i.e., they are found to enhance the 4S characteristics namely speed, sensitivity, selectivity and stability. Improvement of such types of sensors used for detection of various air pollutants, which are reported in last two decades, is highlighted herein.
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Borges, Paulo A V; Guerreiro, Orlando; Ferreira, Maria T; Borges, Annabella; Ferreira, Filomena; Bicudo, Nuno; Nunes, Lina; Marcos, Rita S; Arroz, Ana M; Scheffrahn, Rudolf H; Myles, Timothy G
2014-01-01
The dispersal flights of West Indian drywood termite, Cryptotermes brevis (Walker) (Isoptera: Kalotermitidae) were surveyed in the major cities of Azores. The sampling device used to estimate termite density consisted of a yellow adhesive trap (size 45 by 24 cm), placed with an artificial or natural light source in a dark attic environment. In addition, data from two other projects were used to improve the knowledge about the geographical distribution of the species. The level of infestation in the two main Azorean towns differed, with high levels in the houses of Angra do Heroísmo, whereas in Ponta Delgada, there are fewer houses with high levels of infestation. The infestation in Ponta Delgada shows a pattern of spreading from the center outward to the city's periphery, whereas in Angra do Heroísmo, there was a pattern of spreading outward from several foci. The heavy infestation observed in Angra do Heroísmo and the clear increase of infestation levels observed from 2010 to 2011 is a reason for concern and calls for an urgent application of an Integrated Pest Management (IPM) control strategy. © The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.
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Yamasaki, Akio; Onishi, Hideya; Imaizumi, Akira; Kawamoto, Makoto; Fujimura, Akiko; Oyama, Yasuhiro; Katano, Mitsuo
2016-08-01
Hedgehog signaling is activated in pancreatic cancer and could be a therapeutic target. We previously demonstrated that recombination signal binding protein for immunoglobulin-kappa-J region (RBPJ) and mastermind-like 3 (MAML3) contribute to the hypoxia-induced up-regulation of Smoothened (SMO) transcription. We have also shown that protein-bound polysaccharide-K (PSK) could be effective for refractory pancreatic cancer that down-regulates SMO transcription under hypoxia. In this study, we evaluated whether the anticancer mechanism of PSK involves inhibiting RBPJ and MAML3 expression under hypoxia. PSK reduced SMO, MAML3 and RBPJ expression in pancreatic cancer cells under hypoxia. PSK also blocked RBPJ-induced invasiveness under hypoxia by inhibiting matrix metalloproteinase expression. Lastly, we showed that PSK attenuated RBPJ-induced proliferation both in vitro and in vivo. These results suggest that PSK suppresses Hedgehog signaling through down-regulation of MAML3 and RBPJ transcription under hypoxia, inhibiting the induction of a malignant phenotype in pancreatic cancer. Our results may lead to development of new treatments for refractory pancreatic cancer using PSK as a Hedgehog inhibitor. Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.
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He, Miao; Kratz, Lisa E.; Michel, Joshua J.; Vallejo, Abbe N.; Ferris, Laura; Kelley, Richard I.; Hoover, Jacqueline J.; Jukic, Drazen; Gibson, K. Michael; Wolfe, Lynne A.; Ramachandran, Dhanya; Zwick, Michael E.; Vockley, Jerry
2011-01-01
Defects in cholesterol synthesis result in a wide variety of symptoms, from neonatal lethality to the relatively mild dysmorphic features and developmental delay found in individuals with Smith-Lemli-Opitz syndrome. We report here the identification of mutations in sterol-C4-methyl oxidase–like gene (SC4MOL) as the cause of an autosomal recessive syndrome in a human patient with psoriasiform dermatitis, arthralgias, congenital cataracts, microcephaly, and developmental delay. This gene encodes a sterol-C4-methyl oxidase (SMO), which catalyzes demethylation of C4-methylsterols in the cholesterol synthesis pathway. C4-Methylsterols are meiosis-activating sterols (MASs). They exist at high concentrations in the testis and ovary and play roles in meiosis activation. In this study, we found that an accumulation of MASs in the patient led to cell overproliferation in both skin and blood. SMO deficiency also substantially altered immunocyte phenotype and in vitro function. MASs serve as ligands for liver X receptors α and β (LXRα and LXRβ), which are important in regulating not only lipid transport in the epidermis, but also innate and adaptive immunity. Deficiency of SMO represents a biochemical defect in the cholesterol synthesis pathway, the clinical spectrum of which remains to be defined. PMID:21285510
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Basal cell carcinoma pathogenesis and therapy involving hedgehog signaling and beyond.
Bakshi, Anshika; Chaudhary, Sandeep C; Rana, Mehtab; Elmets, Craig A; Athar, Mohammad
2017-12-01
Basal cell carcinoma (BCC) of the skin is driven by aberrant hedgehog signaling. Thus blocking this signaling pathway by small molecules such as vismodegib inhibits tumor growth. Primary cilium in the epidermal cells plays an integral role in the processing of hedgehog signaling-related proteins. Recent genomic studies point to the involvement of additional genetic mutations that might be associated with the development of BCCs, suggesting significance of other signaling pathways, such as WNT, NOTCH, mTOR, and Hippo, aside from hedgehog in the pathogenesis of this human neoplasm. Some of these pathways could be regulated by noncoding microRNA. Altered microRNA expression profile is recognized with the progression of these lesions. Stopping treatment with Smoothened (SMO) inhibitors often leads to tumor reoccurrence in the patients with basal cell nevus syndrome, who develop 10-100 of BCCs. In addition, the initial effectiveness of these SMO inhibitors is impaired due to the onset of mutations in the drug-binding domain of SMO. These data point to a need to develop strategies to overcome tumor recurrence and resistance and to enhance efficacy by developing novel single agent-based or multiple agents-based combinatorial approaches. Immunotherapy and photodynamic therapy could be additional successful approaches particularly if developed in combination with chemotherapy for inoperable and metastatic BCCs. © 2017 Wiley Periodicals, Inc.
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Basal cell carcinoma pathogenesis and therapy involving hedgehog signaling and beyond
Bakshi, Anshika; Chaudhary, Sandeep C.; Rana, Mehtab; Elmets, Craig A.; Athar, Mohammad
2018-01-01
Basal cell carcinoma (BCC) of the skin is driven by aberrant hedgehog signaling. Thus blocking this signaling pathway by small molecules such as vismodegib inhibits tumor growth. Primary cilium in the epidermal cells plays an integral role in the processing of hedgehog signaling-related proteins. Recent genomic studies point to the involvement of additional genetic mutations that might be associated with the development of BCCs, suggesting significance of other signaling pathways, such as WNT, NOTCH, mTOR, and Hippo, aside from hedgehog in the pathogenesis of this human neoplasm. Some of these pathways could be regulated by noncoding microRNA. Altered microRNA expression profile is recognized with the progression of these lesions. Stopping treatment with Smoothened (SMO) inhibitors often leads to tumor reoccurrence in the patients with basal cell nevus syndrome, who develop 10–100 of BCCs. In addition, the initial effectiveness of these SMO inhibitors is impaired due to the onset of mutations in the drug-binding domain of SMO. These data point to a need to develop strategies to overcome tumor recurrence and resistance and to enhance efficacy by developing novel single agent-based or multiple agents-based combinatorial approaches. Immunotherapy and photodynamic therapy could be additional successful approaches particularly if developed in combination with chemotherapy for inoperable and metastatic BCCs. PMID:28574612
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Nikodinovic-Runic, Jasmina; Coulombel, Lydie; Francuski, Djordje; Sharma, Narain D; Boyd, Derek R; Ferrall, Rory Moore O; O'Connor, Kevin E
2013-06-01
Nine different sulfur-containing compounds were biotransformed to the corresponding sulfoxides by Escherichia coli Bl21(DE3) cells expressing styrene monooxygenase (SMO) from Pseudomonas putida CA-3. Thioanisole was consumed at 83.3 μmoles min(-1) g cell dry weight(-1) resulting mainly in the formation of R-thioanisole sulfoxide with an enantiomeric excess (ee) value of 45 %. The rate of 2-methyl-, 2-chloro- and 2-bromo-thioanisole consumption was 2-fold lower than that of thioanisole. Surprisingly, the 2-methylthioanisole sulfoxide product had the opposite (S) configuration to that of the other 2-substituted thioanisole derivatives and had a higher ee value (84 %). The rate of oxidation of 4-substituted thioanisoles was higher than the corresponding 2-substituted substrates but the ee values of the products were consistently lower (10-23 %). The rate of benzo[b]thiophene and 2-methylbenzo[b]thiophene sulfoxidation was approximately 10-fold lower than that of thioanisole. The ee value of the benzo[b]thiophene sulfoxide could not be determined as the product racemized rapidly. E. coli cells expressing an engineered SMO (SMOeng R3-11) oxidised 2-substituted thioanisoles between 1.8- and 2.8-fold faster compared to cells expressing the wild-type enzyme. SMOeng R3-11 oxidised benzo[b]thiophene and 2-methylbenzo[b]thiophene 10.1 and 5.6 times faster that the wild-type enzyme. The stereospecificity of the reaction catalysed by SMOeng was unchanged from that of the wild type. Using the X-ray crystal structure of the P. putida S12 SMO, it was evident that the entrance of substrates into the SMO active site is limited by the binding pocket bottleneck formed by the side chains of Val-211 and Asn-46 carboxyamide group.
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NASA Technical Reports Server (NTRS)
Ellerby, Gwenn E. C.; Lee, Stuart M. C.; Stroud, Leah; Norcross, Jason; Gernhardt, Michael; Soller, Babs R.
2008-01-01
Consideration for lunar and planetary exploration space suit design can be enhanced by investigating the physiologic responses of individual muscles during locomotion in reduced gravity. Near-infrared spectroscopy (NIRS) provides a non-invasive method to study the physiology of individual muscles in ambulatory subjects during reduced gravity simulations. PURPOSE: To investigate calf muscle oxygen saturation (SmO2) and pH during reduced gravity walking at varying treadmill inclines and added mass conditions using NIRS. METHODS: Four male subjects aged 42.3 +/- 1.7 years (mean +/- SE) and weighing 77.9 +/- 2.4 kg walked at a moderate speed (3.2 +/- 0.2 km/h) on a treadmill at inclines of 0, 10, 20, and 30%. Unsuited subjects were attached to a partial gravity simulator which unloaded the subject to simulate body weight plus the additional weight of a space suit (121 kg) in lunar gravity (0.17G). Masses of 0, 11, 23, and 34 kg were added to the subject and then unloaded to maintain constant weight. Spectra were collected from the lateral gastrocnemius (LG), and SmO2 and pH were calculated using previously published methods (Yang et al. 2007 Optics Express ; Soller et al. 2008 J Appl Physiol). The effects of incline and added mass on SmO2 and pH were analyzed through repeated measures ANOVA. RESULTS: SmO2 and pH were both unchanged by added mass (p>0.05), so data from trials at the same incline were averaged. LG SmO2 decreased significantly with increasing incline (p=0.003) from 61.1 +/- 2.0% at 0% incline to 48.7 +/- 2.6% at 30% incline, while pH was unchanged by incline (p=0.12). CONCLUSION: Increasing the incline (and thus work performed) during walking causes the LG to extract more oxygen from the blood supply, presumably to support the increased metabolic cost of uphill walking. The lack of an effect of incline on pH may indicate that, while the intensity of exercise has increased, the LG has not reached a level of work above the anaerobic threshold. In these preliminary studies, 30% incline walking at reduced gravity may not require anaerobic LG activity due to the low exercise intensity (42.8 +/- 1.6% of VO(sub 2max)). It is also possible that at reduced gravity additional work is being done by muscle groups other than the calf.
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N-terminus determines activity and specificity of styrene monooxygenase reductases.
Heine, Thomas; Scholtissek, Anika; Westphal, Adrie H; van Berkel, Willem J H; Tischler, Dirk
2017-12-01
Styrene monooxygenases (SMOs) are two-enzyme systems that catalyze the enantioselective epoxidation of styrene to (S)-styrene oxide. The FADH 2 co-substrate of the epoxidase component (StyA) is supplied by an NADH-dependent flavin reductase (StyB). The genome of Rhodococcus opacus 1CP encodes two SMO systems. One system, which we define as E1-type, displays homology to the SMO from Pseudomonas taiwanensis VLB120. The other system, originally reported as a fused system (RoStyA2B), is defined as E2-type. Here we found that E1-type RoStyB is inhibited by FMN, while RoStyA2B is known to be active with FMN. To rationalize the observed specificity of RoStyB for FAD, we generated an artificial reductase, designated as RoStyBart, in which the first 22 amino acid residues of RoStyB were joined to the reductase part of RoStyA2B, while the oxygenase part (A2) was removed. RoStyBart mainly purified as apo-protein and mimicked RoStyB in being inhibited by FMN. Pre-incubation with FAD yielded a turnover number at 30°C of 133.9±3.5s -1 , one of the highest rates observed for StyB reductases. RoStyBart holo-enzyme switches to a ping-pong mechanism and fluorescence analysis indicated for unproductive binding of FMN to the second (co-substrate) binding site. In summary, it is shown for the first time that optimization of the N-termini of StyB reductases allows the evolution of their activity and specificity. Copyright © 2017 Elsevier B.V. All rights reserved.
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Rocha Filho, Edilberto A; Costa, Maria L; Cecatti, Jose G; Parpinelli, Mary A; Haddad, Samira M; Pacagnella, Rodolfo C; Sousa, Maria H; Melo, Elias F; Surita, Fernanda G; Souza, Joao P
2015-02-01
To assess the occurrence of severe maternal complications owing to postpartum hemorrhage (PPH) and its associated factors. A secondary analysis of data from a multicenter cross-sectional prospective surveillance study included 9555 cases of severe maternal morbidity at 27 centers in Brazil between July 2009 and June 2010. Complications of PPH, conditions of severity management, and sociodemographic and obstetric characteristics were assessed. Factors independently associated with severe maternal outcome (SMO) were identified using multiple regression analysis. Overall, 1192 (12.5%) of the 9555 women experienced complications owing to PPH (981 had potentially life-threatening conditions, 181 maternal near miss, and 30 had died). The SMO ratio was 2.6 per 1000 live births among women with PPH and 8.5 per 1000 live births among women with other complications. Women with PPH had a higher risk of blood transfusion and return to the operating theater than did those with complications from other causes. Maternal age, length of pregnancy, previous uterine scar, and cesarean delivery were the main factors associated with an increased risk of SMO secondary to PPH. PPH frequently leads to severe maternal morbidity. A surveillance system can identify the main causes of morbidity and could help to improve care, especially among women identified as being at high risk of PPH. Copyright © 2014 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.
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Muntner, Paul; Joyce, Cara; Holt, Elizabeth; He, Jiang; Morisky, Donald; Webber, Larry S; Krousel-Wood, Marie
2011-05-01
Self-report scales are used to assess medication adherence. Data on how to discriminate change in self-reported adherence over time from random variability are limited. To determine the minimal detectable change for scores on the 8-item Morisky Medication Adherence Scale (MMAS-8). The MMAS-8 was administered twice, using a standard telephone script, with administration separated by 14-22 days, to 210 participants taking antihypertensive medication in the CoSMO (Cohort Study of Medication Adherence among Older Adults). MMAS-8 scores were calculated and participants were grouped into previously defined categories (<6, 6 to <8, and 8 for low, medium, and high adherence). The mean (SD) age of participants was 78.1 (5.8) years, 43.8% were black, and 68.1% were women. Overall, 8.1% (17/210), 16.2% (34/210), and 51.0% (107/210) of participants had low, medium, and high MMAS-8 scores, respectively, at both survey administrations (overall agreement 75.2%; 158/210). The weighted κ statistic was 0.63 (95% CI 0.53 to 0.72). The intraclass correlation coefficient was 0.78. The within-person standard error of the mean for change in MMAS-8 scores was 0.81, which equated to a minimal detectable change of 1.98 points. Only 4.3% (9/210) of the participants had a change in MMAS-8 of 2 or more points between survey administrations. Within-person changes in MMAS-8 scores of 2 or more points over time may represent a real change in antihypertensive medication adherence.
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Luck, J Carter; Miller, Amanda J; Aziz, Faisal; Radtka, John F; Proctor, David N; Leuenberger, Urs A; Sinoway, Lawrence I; Muller, Matthew D
2017-07-01
Peripheral artery disease (PAD) is an atherosclerotic vascular disease that affects 200 million people worldwide. Although PAD primarily affects large arteries, it is also associated with microvascular dysfunction, an exaggerated blood pressure (BP) response to exercise, and high cardiovascular mortality. We hypothesized that fatiguing plantar flexion exercise that evokes claudication elicits a greater reduction in skeletal muscle oxygenation (SmO 2 ) and a higher rise in BP in PAD compared with age-matched healthy subjects, but low-intensity steady-state plantar flexion elicits similar responses between groups. In the first experiment, eight patients with PAD and eight healthy controls performed fatiguing plantar flexion exercise (from 0.5 to 7 kg for up to 14 min). In the second experiment, seven patients with PAD and seven healthy controls performed low-intensity plantar flexion exercise (2.0 kg for 14 min). BP, heart rate (HR), and SmO 2 were measured continuously using near-infrared spectroscopy (NIRS). SmO 2 is the ratio of oxygenated hemoglobin to total hemoglobin, expressed as a percent. At fatigue, patients with PAD had a greater increase in mean arterial BP (18 ± 2 vs. vs. 10 ± 2 mmHg, P = 0.029) and HR (14 ± 2 vs. 6 ± 2 beats/min, P = 0.033) and a greater reduction in SmO 2 (-54 ± 10 vs. -12 ± 4%, P = 0.001). However, both groups had similar physiological responses to low-intensity, nonpainful plantar flexion exercise. These data suggest that patients with PAD have altered oxygen uptake and/or utilization during fatiguing exercise coincident with an augmented BP response. NEW & NOTEWORTHY In this laboratory study, patients with peripheral artery disease performed plantar flexion exercise in the supine posture until symptoms of claudication occurred. Relative to age- and sex-matched healthy subjects we found that patients had a higher blood pressure response, a higher heart rate response, and a greater reduction in skeletal muscle oxygenation as determined by near-infrared spectroscopy. Our data suggest that muscle ischemia contributes to the augmented exercise pressor reflex in peripheral artery disease. Copyright © 2017 the American Physiological Society.
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Wang, Yihan; Peng, Qian; Jia, Hongyuan; Du, Xiao
2016-01-01
The Hedgehog (Hh) signaling pathway has recently been reported to be associated with the prognosis of digestive system cancers. However, the results are inconsistent. This study aimed to investigate the association between Hh pathway components and survival outcomes in patients with digestive system cancers. We conducted a comprehensive retrieval in PubMed, EMBASE and Cochrane library for relevant literatures until May 1st, 2015. The pooled hazard ratios (HRs) for overall survival (OS) and disease-free survival (DFS) with 95% confidence intervals (CIs) were calculated to clarify the prognostic value of Hh pathway components, including Shh, Gli1, Gli2, Smo and Ptch1. A total of 16 eligible articles with 3222 patients were included in the meta-analysis. Pooled HR suggested that over-expression of Shh and Gli1 were both associated with poor OS (HR = 1.87, 95% CI: 1.14-3.07 and HR = 1.96, 95% CI: 1.66-2.32, respectively) and DFS (HR = 2.37, 95% CI: 1.19-4.72 and HR = 2.18, 95% CI: 1.61-2.96, respectively). In addition, over-expression of Smo was associated with poor DFS (HR = 1.38, 95% CI: 1.08-1.75). This study reveals that over-expressed Hh pathway components, including Shh, Gli1 and Smo, are associated with poor prognosis in digestive system cancer patients. Hh signaling pathway may become a potential therapeutic target in digestive system cancers.
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Mobile geographic information system solution for pavement condition surveys [summary].
DOT National Transportation Integrated Search
2012-01-01
The State Materials Office (SMO) of the Florida : Department of Transportation (FDOT) performs : annual Pavement Condition Surveys (PCS) of : the Departments extensive pavement network. : This work is performed by single-person crews in : inertial...
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Semiconducting Metal Oxide Based Sensors for Selective Gas Pollutant Detection
Kanan, Sofian M.; El-Kadri, Oussama M.; Abu-Yousef, Imad A.; Kanan, Marsha C.
2009-01-01
A review of some papers published in the last fifty years that focus on the semiconducting metal oxide (SMO) based sensors for the selective and sensitive detection of various environmental pollutants is presented. PMID:22408500
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MacManus-Driscoll, Judith; Suwardi, Ady; Kursumovic, Ahmed; ...
2015-05-05
Auxetic-like strain states were generated in self-assembled nanocomposite thin films of (Ba 0.6Sr 0.4TiO 3) 1–x – (Sm 2O 3) x(BSTO – SmO). A switch from auxetic-like to elastic-like strain behavior was observed for x > 0.50, when the SmO switched from being nanopillars in the BSTO matrix to being the matrix with BSTO nanopillars embedded in it. A simple model was adopted to explain how in-plane strain varies with x. At high x (0.75), strongly enhanced ferroelectric properties were obtained compared to pure BSTO films. Furthermore, the nanocomposite method represents a powerful new way to tune the properties ofmore » a wide range of strongly correlated metal oxides whose properties are very sensitive to strain.« less
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Janus Monolayer Transition-Metal Dichalcogenides.
Zhang, Jing; Jia, Shuai; Kholmanov, Iskandar; Dong, Liang; Er, Dequan; Chen, Weibing; Guo, Hua; Jin, Zehua; Shenoy, Vivek B; Shi, Li; Lou, Jun
2017-08-22
The crystal configuration of sandwiched S-Mo-Se structure (Janus SMoSe) at the monolayer limit has been synthesized and carefully characterized in this work. By controlled sulfurization of monolayer MoSe 2 , the top layer of selenium atoms is substituted by sulfur atoms, while the bottom selenium layer remains intact. The structure of this material is systematically investigated by Raman, photoluminescence, transmission electron microscopy, and X-ray photoelectron spectroscopy and confirmed by time-of-flight secondary ion mass spectrometry. Density functional theory (DFT) calculations are performed to better understand the Raman vibration modes and electronic structures of the Janus SMoSe monolayer, which are found to correlate well with corresponding experimental results. Finally, high basal plane hydrogen evolution reaction activity is discovered for the Janus monolayer, and DFT calculation implies that the activity originates from the synergistic effect of the intrinsic defects and structural strain inherent in the Janus structure.
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NASA Astrophysics Data System (ADS)
Zhang, Xianjun; Zhao, Fei; Wu, Yiran; Yang, Jun; Han, Gye Won; Zhao, Suwen; Ishchenko, Andrii; Ye, Lintao; Lin, Xi; Ding, Kang; Dharmarajan, Venkatasubramanian; Griffin, Patrick R.; Gati, Cornelius; Nelson, Garrett; Hunter, Mark S.; Hanson, Michael A.; Cherezov, Vadim; Stevens, Raymond C.; Tan, Wenfu; Tao, Houchao; Xu, Fei
2017-05-01
The Smoothened receptor (SMO) belongs to the Class Frizzled of the G protein-coupled receptor (GPCR) superfamily, constituting a key component of the Hedgehog signalling pathway. Here we report the crystal structure of the multi-domain human SMO, bound and stabilized by a designed tool ligand TC114, using an X-ray free-electron laser source at 2.9 Å. The structure reveals a precise arrangement of three distinct domains: a seven-transmembrane helices domain (TMD), a hinge domain (HD) and an intact extracellular cysteine-rich domain (CRD). This architecture enables allosteric interactions between the domains that are important for ligand recognition and receptor activation. By combining the structural data, molecular dynamics simulation, and hydrogen-deuterium-exchange analysis, we demonstrate that transmembrane helix VI, extracellular loop 3 and the HD play a central role in transmitting the signal employing a unique GPCR activation mechanism, distinct from other multi-domain GPCRs.
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Janus Monolayer Transition-Metal Dichalcogenides
Zhang, Jing; Jia, Shuai; Kholmanov, Iskandar; ...
2017-08-03
In this work, the crystal configuration of sandwiched S–Mo–Se structure (Janus SMoSe) at the monolayer limit has been synthesized and carefully characterized. By controlled sulfurization of monolayer MoSe 2, the top layer of selenium atoms is substituted by sulfur atoms, while the bottom selenium layer remains intact. Furthermore, the structure of this material is systematically investigated by Raman, photoluminescence, transmission electron microscopy, and X-ray photoelectron spectroscopy and confirmed by time-of-flight secondary ion mass spectrometry. Density functional theory (DFT) calculations are performed to better understand the Raman vibration modes and electronic structures of the Janus SMoSe monolayer, which are found tomore » correlate well with corresponding experimental results. Finally, high basal plane hydrogen evolution reaction activity is discovered for the Janus monolayer, and DFT calculation implies that the activity originates from the synergistic effect of the intrinsic defects and structural strain inherent in the Janus structure.« less
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Zhang, Xianjun; Zhao, Fei; Wu, Yiran
Here, the Smoothened receptor (SMO) belongs to the Class Frizzled of the G protein-coupled receptor (GPCR) superfamily, constituting a key component of the Hedgehog signalling pathway. Here we report the crystal structure of the multi-domain human SMO, bound and stabilized by a designed tool ligand TC114, using an X-ray free-electron laser source at 2.9 Å. The structure reveals a precise arrangement of three distinct domains: a seven-transmembrane helices domain (TMD), a hinge domain (HD) and an intact extracellular cysteine-rich domain (CRD). This architecture enables allosteric interactions between the domains that are important for ligand recognition and receptor activation. By combiningmore » the structural data, molecular dynamics simulation, and hydrogen-deuterium-exchange analysis, we demonstrate that transmembrane helix VI, extracellular loop 3 and the HD play a central role in transmitting the signal employing a unique GPCR activation mechanism, distinct from other multi-domain GPCRs.« less
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Experimental validation of structural optimization methods
NASA Technical Reports Server (NTRS)
Adelman, Howard M.
1992-01-01
The topic of validating structural optimization methods by use of experimental results is addressed. The need for validating the methods as a way of effecting a greater and an accelerated acceptance of formal optimization methods by practicing engineering designers is described. The range of validation strategies is defined which includes comparison of optimization results with more traditional design approaches, establishing the accuracy of analyses used, and finally experimental validation of the optimization results. Examples of the use of experimental results to validate optimization techniques are described. The examples include experimental validation of the following: optimum design of a trussed beam; combined control-structure design of a cable-supported beam simulating an actively controlled space structure; minimum weight design of a beam with frequency constraints; minimization of the vibration response of helicopter rotor blade; minimum weight design of a turbine blade disk; aeroelastic optimization of an aircraft vertical fin; airfoil shape optimization for drag minimization; optimization of the shape of a hole in a plate for stress minimization; optimization to minimize beam dynamic response; and structural optimization of a low vibration helicopter rotor.
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A combined spectroscopic and plasma chemical kinetic analysis of ionospheric samarium releases
NASA Astrophysics Data System (ADS)
Holmes, Jeffrey M.; Dressler, Rainer A.; Pedersen, Todd R.; Caton, Ronald G.; Miller, Daniel
2017-05-01
Two rocket-borne releases of samarium vapor in the upper atmosphere occurred in May 2013, as part of the Metal Oxide Space Clouds experiment. The releases were characterized by a combination of optical and RF diagnostic instruments located at the Roi-Namur launch site and surrounding islands and atolls. The evolution of the optical spectrum of the solar-illuminated cloud was recorded with a spectrograph covering a 400-800 nm spectral range. The spectra exhibit two distinct spectral regions centered at 496 and 636 nm within which the relative intensities change insignificantly. The ratio between the integrated intensities within these regions, however, changes with time, suggesting that they are associated with different species. With the help of an equilibrium plasma spectral model we attribute the region centered at 496 nm to neutral samarium atoms (Sm I radiance) and features peaking at 649 nm to a molecular species. No evidence for structure due to Sm+ (Sm II) is identified. The persistence of the Sm I radiance suggests a high dissociative recombination rate for the chemi-ionization product, SmO+. A one-dimensional plasma chemical kinetic model of the evolution of the density ratio NSmO/NSm(t) demonstrates that the molecular feature peaking at 649 nm can be attributed to SmO radiance. SmO+ radiance is not identified. By adjusting the Sm vapor mass of the chemical kinetic model input to match the evolution of the total electron density determined by ionosonde data, we conclude that less than 5% of the payload samarium was vaporized.
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Rennert, Christiane; Eplinius, Franziska; Hofmann, Ute; Johänning, Janina; Rolfs, Franziska; Schmidt-Heck, Wolfgang; Guthke, Reinhardt; Gebhardt, Rolf; Ricken, Albert M; Matz-Soja, Madlen
2017-11-01
The Hedgehog signaling pathway is known to be involved in embryogenesis, tissue remodeling, and carcinogenesis. Because of its involvement in carcinogenesis, it seems an interesting target for cancer therapy. Indeed, Sonidegib, an approved inhibitor of the Hedgehog receptor Smoothened (Smo), is highly active against diverse carcinomas, but its use is also reported to be associated with several systemic side effects. Our former work in adult mice demonstrated hepatic Hedgehog signaling to play a key role in the insulin-like growth factor axis and lipid metabolism. The current work using mice with an embryonic and hepatocyte-specific Smo deletion describes an adverse impact of the hepatic Hedgehog pathway on female fertility. In female SAC-KO mice, we detected androgenization characterized by a 3.3-fold increase in testosterone at 12 weeks of age based on an impressive induction of steroidogenic gene expression in hepatocytes, but not in the classic steroidogenic organs (ovary and adrenal gland). Along with the elevated level of testosterone, the female SAC-KO mice showed infertility characterized by juvenile reproductive organs and acyclicity. The endocrine and reproductive alterations resembled polycystic ovarian syndrome and could be confirmed in a second mouse model with conditional deletion of Smo at 8 weeks of age after an extended period of 8 months. We conclude that the down-regulation of hepatic Hedgehog signaling leads to an impaired hormonal balance by the induction of steroidogenesis in the liver. These effects of Hedgehog signaling inhibition should be considered when using Hedgehog inhibitors as anti-cancer drugs.
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NASA Astrophysics Data System (ADS)
O'Neill, Andrea; Barnard, Patrick; Erikson, Li; Foxgrover, Amy; Limber, Patrick; Vitousek, Sean; Fitzgibbon, Michael; Wood, Nathan
2017-04-01
The risk of coastal flooding will increase for many low-lying coastal regions as predominant contributions to flooding, including sea level, storm surge, wave setup, and storm-related fluvial discharge, are altered with climate change. Community leaders and local governments therefore look to science to provide insight into how climate change may affect their areas. Many studies of future coastal flooding vulnerability consider sea level and tides, but ignore other important factors that elevate flood levels during storm events, such as waves, surge, and discharge. Here we present a modelling approach that considers a broad range of relevant processes contributing to elevated storm water levels for open coast and embayment settings along the U.S. West Coast. Additionally, we present online tools for communicating community-relevant projected vulnerabilities. The Coastal Storm Modeling System (CoSMoS) is a numerical modeling system developed to predict coastal flooding due to both sea-level rise (SLR) and plausible 21st century storms for active-margin settings like the U.S. West Coast. CoSMoS applies a predominantly deterministic framework of multi-scale models encompassing large geographic scales (100s to 1000s of kilometers) to small-scale features (10s to 1000s of meters), resulting in flood extents that can be projected at a local resolution (2 meters). In the latest iteration of CoSMoS applied to Southern California, U.S., efforts were made to incorporate water level fluctuations in response to regional storm impacts, locally wind-generated waves, coastal river discharge, and decadal-scale shoreline and cliff changes. Coastal hazard projections are available in a user-friendly web-based tool (www.prbo.org/ocof), where users can view variations in flood extent, maximum flood depth, current speeds, and wave heights in response to a range of potential SLR and storm combinations, providing direct support to adaptation and management decisions. In order to capture the societal aspect of the hazard, projections are combined with socioeconomic exposure to produce clear, actionable information (https://www.usgs.gov/apps/hera/); this integrated approach to hazard displays provides an example of how to effectively translate complex climate impacts projections into simple, societally-relevant information.
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Optimization of insulation of a linear Fresnel collector
NASA Astrophysics Data System (ADS)
Ardekani, Mohammad Moghimi; Craig, Ken J.; Meyer, Josua P.
2017-06-01
This study presents a simulation based optimization study of insulation around the cavity receiver of a Linear Fresnel Collector. This optimization study focuses on minimizing heat losses from a cavity receiver (maximizing plant thermal efficiency), while minimizing insulation cross-sectional area (minimizing material cost and cavity dead load), which leads to a cheaper and thermally more efficient LFC cavity receiver.
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Mobile geographic information system (GIS) solution for pavement condition surveys.
DOT National Transportation Integrated Search
2012-06-28
This report discusses the design and implementation of a software-based solution that will improve the data collection processes during the Pavement Condition Surveys (PCS) conducted by the State Materials Office (SMO) of the Florida Department of Tr...
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Optimal trajectories of aircraft and spacecraft
NASA Technical Reports Server (NTRS)
Miele, A.
1990-01-01
Work done on algorithms for the numerical solutions of optimal control problems and their application to the computation of optimal flight trajectories of aircraft and spacecraft is summarized. General considerations on calculus of variations, optimal control, numerical algorithms, and applications of these algorithms to real-world problems are presented. The sequential gradient-restoration algorithm (SGRA) is examined for the numerical solution of optimal control problems of the Bolza type. Both the primal formulation and the dual formulation are discussed. Aircraft trajectories, in particular, the application of the dual sequential gradient-restoration algorithm (DSGRA) to the determination of optimal flight trajectories in the presence of windshear are described. Both take-off trajectories and abort landing trajectories are discussed. Take-off trajectories are optimized by minimizing the peak deviation of the absolute path inclination from a reference value. Abort landing trajectories are optimized by minimizing the peak drop of altitude from a reference value. Abort landing trajectories are optimized by minimizing the peak drop of altitude from a reference value. The survival capability of an aircraft in a severe windshear is discussed, and the optimal trajectories are found to be superior to both constant pitch trajectories and maximum angle of attack trajectories. Spacecraft trajectories, in particular, the application of the primal sequential gradient-restoration algorithm (PSGRA) to the determination of optimal flight trajectories for aeroassisted orbital transfer are examined. Both the coplanar case and the noncoplanar case are discussed within the frame of three problems: minimization of the total characteristic velocity; minimization of the time integral of the square of the path inclination; and minimization of the peak heating rate. The solution of the second problem is called nearly-grazing solution, and its merits are pointed out as a useful engineering compromise between energy requirements and aerodynamics heating requirements.
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Optimal trajectories for an aerospace plane. Part 2: Data, tables, and graphs
NASA Technical Reports Server (NTRS)
Miele, Angelo; Lee, W. Y.; Wu, G. D.
1990-01-01
Data, tables, and graphs relative to the optimal trajectories for an aerospace plane are presented. A single-stage-to-orbit (SSTO) configuration is considered, and the transition from low supersonic speeds to orbital speeds is studied for a single aerodynamic model (GHAME) and three engine models. Four optimization problems are solved using the sequential gradient-restoration algorithm for optimal control problems: (1) minimization of the weight of fuel consumed; (2) minimization of the peak dynamic pressure; (3) minimization of the peak heating rate; and (4) minimization of the peak tangential acceleration. The above optimization studies are carried out for different combinations of constraints, specifically: initial path inclination that is either free or given; dynamic pressure that is either free or bounded; and tangential acceleration that is either free or bounded.
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NASA Astrophysics Data System (ADS)
Hamada, Aulia; Rosyidi, Cucuk Nur; Jauhari, Wakhid Ahmad
2017-11-01
Minimizing processing time in a production system can increase the efficiency of a manufacturing company. Processing time are influenced by application of modern technology and machining parameter. Application of modern technology can be apply by use of CNC machining, one of the machining process can be done with a CNC machining is turning. However, the machining parameters not only affect the processing time but also affect the environmental impact. Hence, optimization model is needed to optimize the machining parameters to minimize the processing time and environmental impact. This research developed a multi-objective optimization to minimize the processing time and environmental impact in CNC turning process which will result in optimal decision variables of cutting speed and feed rate. Environmental impact is converted from environmental burden through the use of eco-indicator 99. The model were solved by using OptQuest optimization software from Oracle Crystal Ball.
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NASA Astrophysics Data System (ADS)
Shinzato, Takashi
2017-02-01
In the present paper, the minimal investment risk for a portfolio optimization problem with imposed budget and investment concentration constraints is considered using replica analysis. Since the minimal investment risk is influenced by the investment concentration constraint (as well as the budget constraint), it is intuitive that the minimal investment risk for the problem with an investment concentration constraint can be larger than that without the constraint (that is, with only the budget constraint). Moreover, a numerical experiment shows the effectiveness of our proposed analysis. In contrast, the standard operations research approach failed to identify accurately the minimal investment risk of the portfolio optimization problem.
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Design and pitch scaling for affordable node transition and EUV insertion scenario
NASA Astrophysics Data System (ADS)
Kim, Ryoung-han; Ryckaert, Julien; Raghavan, Praveen; Sherazi, Yasser; Debacker, Peter; Trivkovic, Darko; Gillijns, Werner; Tan, Ling Ee; Drissi, Youssef; Blanco, Victor; Bekaert, Joost; Mao, Ming; Larivière, Stephane; McIntyre, Greg
2017-04-01
imec's DTCO and EUV achievement toward imec 7nm (iN7) technology node which is industry 5nm node equivalent is reported with a focus on cost and scaling. Patterning-aware design methodology supports both iArF multiple patterning and EUV under one compliant design rule. FinFET device with contacted poly pitch of 42nm and metal pitch of 32nm with 7.5-track, 6.5-track, and 6-track standard cell library are explored. Scaling boosters are used to provide additional scaling and die cost benefit while lessening pitch shrink burden, and it makes EUV insertion more affordable. EUV pattern fidelity is optimized through OPC, SMO, M3D, mask sizing and SRAF. Processed wafers were characterized and edge-placement-error (EPE) variability is validated for EUV insertion. Scale-ability and cost of ownership of EUV patterning in aligned with iN7 standard cell design, integration and patterning specification are discussed.
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Diurnal Cycle of Surface Flows During NAME and Comparison to Model Reanalysis
NASA Astrophysics Data System (ADS)
Ciesielski, P. E.; Johnson, R. H.
2007-05-01
During the North American Monsoon Experiment (NAME) an unprecedented surface data set of winds and thermodynamic variables was collected over the core monsoon region. The surface network included 63 automated sites with 1-30 min resolution data, 27 SMN operational sites (1-3 hourly data), and 56 US operational sites (1-3 hourly data) along the northern fringe of the monsoon region. These data, along with twice daily QuikSCAT oceanic surface winds, were quality controlled and objectively analyzed on to a uniform grid with quarter-degree, 1-h resolution for the period from 1 July - 15 August. An important application of the gridded winds is their use in diagnosing surface vertical motion due to slope flows over the Sierra Madre Occidental (SMO) terrain. With this dataset we examine the diurnal characteristics of surface fields as the monsoon evolves and compare these analyses to similar surface products from the special North American Regional Reanalysis (NARR) for NAME. Observed surface fields indicate that a robust land-sea breeze circulation is present over most of Gulf of California (GOC) region in response to the strong diurnal heating of land masses on both sides of the gulf. For reasons unclear at this time, many features of this land-sea breeze circulation are missing in the NARR. Evolution of the diurnal cycle of temperature and the land- sea breeze circulation as the monsoon progresses through the season shows a strong sensitivity to rainfall over the SMO and the coastal plains. Such a relationship likely reflects changes in land surface characteristics, such as evapotranspiration and albedo, as the forests of the SMO respond to monsoonal rains.
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Dendrosomatic Sonic Hedgehog Signaling in Hippocampal Neurons Regulates Axon Elongation
Petralia, Ronald S.; Ott, Carolyn; Wang, Ya-Xian; Lippincott-Schwartz, Jennifer; Mattson, Mark P.
2015-01-01
The presence of Sonic Hedgehog (Shh) and its signaling components in the neurons of the hippocampus raises a question about what role the Shh signaling pathway may play in these neurons. We show here that activation of the Shh signaling pathway stimulates axon elongation in rat hippocampal neurons. This Shh-induced effect depends on the pathway transducer Smoothened (Smo) and the transcription factor Gli1. The axon itself does not respond directly to Shh; instead, the Shh signal transduction originates from the somatodendritic region of the neurons and occurs in neurons with and without detectable primary cilia. Upon Shh stimulation, Smo localization to dendrites increases significantly. Shh pathway activation results in increased levels of profilin1 (Pfn1), an actin-binding protein. Mutations in Pfn1's actin-binding sites or reduction of Pfn1 eliminate the Shh-induced axon elongation. These findings indicate that Shh can regulate axon growth, which may be critical for development of hippocampal neurons. SIGNIFICANCE STATEMENT Although numerous signaling mechanisms have been identified that act directly on axons to regulate their outgrowth, it is not known whether signals transduced in dendrites may also affect axon outgrowth. We describe here a transcellular signaling pathway in embryonic hippocampal neurons in which activation of Sonic Hedgehog (Shh) receptors in dendrites stimulates axon growth. The pathway involves the dendritic-membrane-associated Shh signal transducer Smoothened (Smo) and the transcription factor Gli, which induces the expression of the gene encoding the actin-binding protein profilin 1. Our findings suggest scenarios in which stimulation of Shh in dendrites results in accelerated outgrowth of the axon, which therefore reaches its presumptive postsynaptic target cell more quickly. By this mechanism, Shh may play critical roles in the development of hippocampal neuronal circuits. PMID:26658865
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Hedgehog-GLI signaling drives self-renewal and tumorigenicity of human melanoma-initiating cells.
Santini, Roberta; Vinci, Maria C; Pandolfi, Silvia; Penachioni, Junia Y; Montagnani, Valentina; Olivito, Biagio; Gattai, Riccardo; Pimpinelli, Nicola; Gerlini, Gianni; Borgognoni, Lorenzo; Stecca, Barbara
2012-09-01
The question of whether cancer stem/tumor-initiating cells (CSC/TIC) exist in human melanomas has arisen in the last few years. Here, we have used nonadherent spheres and the aldehyde dehydrogenase (ALDH) enzymatic activity to enrich for CSC/TIC in a collection of human melanomas obtained from a broad spectrum of sites and stages. We find that melanomaspheres display extensive in vitro self-renewal ability and sustain tumor growth in vivo, generating human melanoma xenografts that recapitulate the phenotypic composition of the parental tumor. Melanomaspheres express high levels of Hedgehog (HH) pathway components and of embryonic pluripotent stem cell factors SOX2, NANOG, OCT4, and KLF4. We show that human melanomas contain a subset of cells expressing high ALDH activity (ALDH(high)), which is endowed with higher self-renewal and tumorigenic abilities than the ALDH(low) population. A good correlation between the number of ALDH(high) cells and sphere formation efficiency was observed. Notably, both pharmacological inhibition of HH signaling by the SMOOTHENED (SMO) antagonist cyclopamine and GLI antagonist GANT61 and stable expression of shRNA targeting either SMO or GLI1 result in a significant decrease in melanoma stem cell self-renewal in vitro and a reduction in the number of ALDH(high) melanoma stem cells. Finally, we show that interference with the HH-GLI pathway through lentiviral-mediated silencing of SMO and GLI1 drastically diminishes tumor initiation of ALDH(high) melanoma stem cells. In conclusion, our data indicate an essential role of the HH-GLI1 signaling in controlling self-renewal and tumor initiation of melanoma CSC/TIC. Targeting HH-GLI1 is thus predicted to reduce the melanoma stem cell compartment. Copyright © 2012 AlphaMed Press.
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Farzam, Parisa; Starkweather, Zack; Franceschini, Maria A
2018-04-01
There is a growing interest in monitoring muscle oxygen saturation (SmO 2 ), which is a localized measure of muscle oxidative metabolism and can be acquired continuously and noninvasively using near-infrared spectroscopy (NIRS) methods. Most NIRS systems are cumbersome, expensive, fiber coupled devices, with use limited to lab settings. A novel, low cost, wireless, wearable has been developed for use in athletic training. In this study, we evaluate the advantages and limitations of this new simple continuous-wave (CW) NIRS device with respect to a benchtop, frequency-domain near-infrared spectroscopy (FDNIRS) system. Oxygen saturation and hemoglobin/myoglobin concentration in the exercising muscles of 17 athletic individuals were measured simultaneously with the two systems, while subjects performed an incremental test on a stationary cycle ergometer. In addition, blood lactate concentration was measured at the end of each increment with a lactate analyzer. During exercise, the correlation coefficients of the SmO 2 and hemoglobin/myoglobin concentrations between the two systems were over 0.70. We also found both systems were insensitive to the presence of thin layers of varying absorption, mimicking different skin colors. Neither system was able to predict the athletes' lactate threshold power accurately by simply using SmO 2 thresholds. Instead, the proprietary software of the wearable device was able to predict the athletes' lactate threshold power within half of one power increment of the cycling test. These results indicate this novel wearable device may provide a physiological indicator of athlete's exertion. © 2018 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.
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Esmolol acutely alters oxygen supply-demand balance in exercising muscles of healthy humans.
Proctor, David N; Luck, J Carter; Maman, Stephan R; Leuenberger, Urs A; Muller, Matthew D
2018-04-01
Beta-adrenoreceptor antagonists (β blockers) reduce systemic O 2 delivery and blood pressure (BP) during exercise, but the subsequent effects on O 2 extraction within the active limb muscles are unknown. In this study, we examined the effects of the fast-acting, β 1 selective blocker esmolol on systemic hemodynamics and leg muscle O 2 saturation (near infrared spectroscopy, NIRS) during submaximal leg ergometry. Our main hypothesis was that esmolol would augment exercise-induced reductions in leg muscle O 2 saturation. Eight healthy adults (6 men, 2 women; 23-67 year) performed light and moderate intensity bouts of recumbent leg cycling before (PRE), during (β 1 -blocked), and 45 min following (POST) intravenous infusion of esmolol. Oxygen uptake, heart rate (HR), BP, and O 2 saturation (SmO 2 ) of the vastus lateralis (VL) and medial gastrocnemius (MG) muscles were measured continuously. Esmolol attenuated the increases in HR and systolic BP during light (-12 ± 9 bpm and -26 ± 12 mmHg vs. PRE) and moderate intensity (-20 ± 10 bpm and -40 ± 18 mmHg vs. PRE) cycling (all P < 0.01). Exercise-induced reductions in SmO 2 occurred to a greater extent during the β 1 -blockade trial in both the VL (P = 0.001 vs. PRE) and MG muscles (P = 0.022 vs. PRE). HR, SBP and SmO 2 were restored during POST (all P < 0.01 vs. β 1 -blocked). In conclusion, esmolol rapidly and reversibly increases O 2 extraction within exercising muscles of healthy humans. © 2018 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.
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Lee, Chewook; Kalmar, Lajos; Xue, Bin; Tompa, Peter; Daughdrill, Gary W; Uversky, Vladimir N; Han, Kyou-Hoon
2014-03-01
IDPs function without relying on three-dimensional structures. No clear rationale for such a behavior is available yet. PreSMos are transient secondary structures observed in the target-free IDPs and serve as the target-binding "active" motifs in IDPs. Prolines are frequently found in the flanking regions of PreSMos. Contribution of prolines to the conformational stability of the helical PreSMos in IDPs is investigated. MD simulations are performed for several IDP segments containing a helical PreSMo and the flanking prolines. To measure the influence of flanking-prolines on the structural content of a helical PreSMo calculations were done for wild type as well as for mutant segments with Pro→Asp, His, Lys, or Ala. The change in the helicity due to removal of a proline was measured both for the PreSMo region and for the flanking regions. The α-helical content in ~70% of the helical PreSMos at the early stage of simulation decreases due to replacement of an N-terminal flanking proline by other residues whereas the helix content in nearly all PreSMos increases when the same replacements occur at the C-terminal flanking region. The helix destabilizing/terminating role of the C-terminal flanking prolines is more pronounced than the helix promoting effect of the N-terminal flanking prolines. This work represents a novel example demonstrating that a proline is encoded in an IDP with a defined purpose. The helical PreSMos presage their target-bound conformations. As they most likely mediate IDP-target binding via conformational selection their helical content can be an important feature for IDP function. Copyright © 2013 Elsevier B.V. All rights reserved.
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Combined shape and topology optimization for minimization of maximal von Mises stress
DOE Office of Scientific and Technical Information (OSTI.GOV)
Lian, Haojie; Christiansen, Asger N.; Tortorelli, Daniel A.
Here, this work shows that a combined shape and topology optimization method can produce optimal 2D designs with minimal stress subject to a volume constraint. The method represents the surface explicitly and discretizes the domain into a simplicial complex which adapts both structural shape and topology. By performing repeated topology and shape optimizations and adaptive mesh updates, we can minimize the maximum von Mises stress using the p-norm stress measure with p-values as high as 30, provided that the stress is calculated with sufficient accuracy.
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Combined shape and topology optimization for minimization of maximal von Mises stress
Lian, Haojie; Christiansen, Asger N.; Tortorelli, Daniel A.; ...
2017-01-27
Here, this work shows that a combined shape and topology optimization method can produce optimal 2D designs with minimal stress subject to a volume constraint. The method represents the surface explicitly and discretizes the domain into a simplicial complex which adapts both structural shape and topology. By performing repeated topology and shape optimizations and adaptive mesh updates, we can minimize the maximum von Mises stress using the p-norm stress measure with p-values as high as 30, provided that the stress is calculated with sufficient accuracy.
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The capability of lithography simulation based on MVM-SEM® system
NASA Astrophysics Data System (ADS)
Yoshikawa, Shingo; Fujii, Nobuaki; Kanno, Koichi; Imai, Hidemichi; Hayano, Katsuya; Miyashita, Hiroyuki; Shida, Soichi; Murakawa, Tsutomu; Kuribara, Masayuki; Matsumoto, Jun; Nakamura, Takayuki; Matsushita, Shohei; Hara, Daisuke; Pang, Linyong
2015-10-01
The 1Xnm technology node lithography is using SMO-ILT, NTD or more complex pattern. Therefore in mask defect inspection, defect verification becomes more difficult because many nuisance defects are detected in aggressive mask feature. One key Technology of mask manufacture is defect verification to use aerial image simulator or other printability simulation. AIMS™ Technology is excellent correlation for the wafer and standards tool for defect verification however it is difficult for verification over hundred numbers or more. We reported capability of defect verification based on lithography simulation with a SEM system that architecture and software is excellent correlation for simple line and space.[1] In this paper, we use a SEM system for the next generation combined with a lithography simulation tool for SMO-ILT, NTD and other complex pattern lithography. Furthermore we will use three dimension (3D) lithography simulation based on Multi Vision Metrology SEM system. Finally, we will confirm the performance of the 2D and 3D lithography simulation based on SEM system for a photomask verification.
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Larson, Joshua; Kirk, Matt; Drier, Eric A.; O’Brien, William; MacKay, James F.; Friedman, Larry; Hoskins, Aaron
2015-01-01
Colocalization Single Molecule Spectroscopy (CoSMoS) has proven to be a useful method for studying the composition, kinetics, and mechanisms of complex cellular machines. Key to the technique is the ability to simultaneously monitor multiple proteins and/or nucleic acids as they interact with one another. Here we describe a protocol for constructing a CoSMoS micromirror Total Internal Reflection Fluorescence Microscope (mmTIRFM). Design and construction of a scientific microscope often requires a number of custom components and a significant time commitment. In our protocol, we have streamlined this process by implementation of a commercially available microscopy platform designed to accommodate the optical components necessary for a mmTIRFM. The mmTIRF system eliminates the need for machining custom parts by the end-user and facilitates optical alignment. Depending on the experience-level of the microscope builder, these time-savings and the following protocol can enable mmTIRF construction to be completed within two months. PMID:25188633
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Larson, Joshua; Kirk, Matt; Drier, Eric A; O'Brien, William; MacKay, James F; Friedman, Larry J; Hoskins, Aaron A
2014-10-01
Colocalization single-molecule spectroscopy (CoSMoS) has proven to be a useful method for studying the composition, kinetics and mechanisms of complex cellular machines. Key to the technique is the ability to simultaneously monitor multiple proteins and/or nucleic acids as they interact with one another. Here we describe a protocol for constructing a CoSMoS micromirror total internal reflection fluorescence microscope (mmTIRFM). Design and construction of a scientific microscope often requires a number of custom components and a substantial time commitment. In our protocol, we have streamlined this process by implementation of a commercially available microscopy platform designed to accommodate the optical components necessary for an mmTIRFM. The mmTIRF system eliminates the need for machining custom parts by the end user and facilitates optical alignment. Depending on the experience level of the microscope builder, these time savings and the following protocol can enable mmTIRF construction to be completed within 2 months.
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Atom-Dependent Edge-Enhanced Second-Harmonic Generation on MoS2 Monolayers.
Lin, Kuang-I; Ho, Yen-Hung; Liu, Shu-Bai; Ciou, Jian-Jhih; Huang, Bo-Ting; Chen, Christopher; Chang, Han-Ching; Tu, Chien-Liang; Chen, Chang-Hsiao
2018-02-14
Edge morphology and lattice orientation of single-crystal molybdenum disulfide (MoS 2 ) monolayers, a transition metal dichalcogenide (TMD), possessing a triangular shape with different edges grown by chemical vapor deposition are characterized by atomic force microscopy and transmission electron microscopy. Multiphoton laser scanning microscopy is utilized to study one-dimensional atomic edges of MoS 2 monolayers with localized midgap electronic states, which result in greatly enhanced optical second-harmonic generation (SHG). Microscopic S-zigzag edge and S-Mo Klein edge (bare Mo atoms protruding from a S-zigzag edge) terminations and the edge-atom dependent resonance energies can therefore be deduced based on SHG images. Theoretical calculations based on density functional theory clearly explain the lower energy of the S-zigzag edge states compared to the corresponding S-Mo Klein edge states. Characterization of the atomic-scale variation of edge-enhanced SHG is a step forward in this full-optical and high-yield technique of atomic-layer TMDs.
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Zhang, Xianjun; Zhao, Fei; Wu, Yiran; ...
2017-05-17
Here, the Smoothened receptor (SMO) belongs to the Class Frizzled of the G protein-coupled receptor (GPCR) superfamily, constituting a key component of the Hedgehog signalling pathway. Here we report the crystal structure of the multi-domain human SMO, bound and stabilized by a designed tool ligand TC114, using an X-ray free-electron laser source at 2.9 Å. The structure reveals a precise arrangement of three distinct domains: a seven-transmembrane helices domain (TMD), a hinge domain (HD) and an intact extracellular cysteine-rich domain (CRD). This architecture enables allosteric interactions between the domains that are important for ligand recognition and receptor activation. By combiningmore » the structural data, molecular dynamics simulation, and hydrogen-deuterium-exchange analysis, we demonstrate that transmembrane helix VI, extracellular loop 3 and the HD play a central role in transmitting the signal employing a unique GPCR activation mechanism, distinct from other multi-domain GPCRs.« less
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Beer, Christiane; Buhr, Petra; Hahn, Heidi; Laubner, Daniela; Wirth, Manfred
2003-07-01
Cultivation of retrovirus packaging cells at 32 degrees C represents a common procedure to achieve high titres in mouse retrovirus production. Gene expression profiling of mouse NIH 3T3 cells producing amphotropic mouse leukaemia virus 4070A revealed that 10 % of the 1176 cellular genes investigated were regulated by temperature shift (37/32 degrees C), while 5 % were affected by retrovirus infection. Strikingly, retrovirus production at 32 degrees C activated the cholesterol biosynthesis/transport pathway and caused an increase in plasma membrane cholesterol levels. Furthermore, these conditions resulted in transcriptional activation of smoothened (smo), patched (ptc) and gli-1; Smo, Ptc and Gli-1, as well as cholesterol, are components of the Sonic hedgehog (Shh) signalling pathway, which directs pattern formation, diversification and tumourigenesis in mammalian cells. These findings suggest a link between cultivation at 32 degrees C, production of MLV-A and the Shh signalling pathway.
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USDA-ARS?s Scientific Manuscript database
The objective of the present study was to assess the relationship between lifestyle factors and abdominal subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) in a community-based setting. Cross-sectional associations between lifestyle factors (dietary quality, physical activity, smo...
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Pledgie-Tracy, Allison; Billam, Madhavi; Hacker, Amy; Sobolewski, Michele D; Woster, Patrick M.; Zhang, Zhe; Casero, Robert A.; Davidson, Nancy E
2009-01-01
Polyamine analogues have demonstrated significant activity against human breast cancer cell lines as single agents as well as in combination with other cytotoxic drugs. This study evaluates the ability of a polyamine analogue N1, N11-bis(ethyl)norspermine (BENSpm) to synergize with six standard chemotherapeutic agents, 5-fluorouracil (FU), fluorodeoxyuridine, cis- diaminechloroplatinum(II) (DDP), paclitaxel, docetaxel, and vinorelbine, in four human breast cancer cell lines and one immortalized, non-tumorigenic mammary epithelial cell line. BENSpm exhibited synergistic inhibitory effect on cell proliferation in combination with 5-FU or paclitaxel in human breast cancer cell lines (MDA-MB-231 and MCF-7) and either antagonistic or less effective in the non-tumorigenic MCF-10A cell line. Synergism was highest with 120 hour concomitant treatment or pre-treatment with BENSpm for 24 hours followed by concomitant treatment for 96 additional hours. Since the cytotoxic effects of many polyamine analogues and cytotoxic agents are believed to act, in part, through induction of the polyamine catabolic enzymes SSAT and SMO, the role of these enzymes on synergistic response was evaluated in MDA-MB-231- and MCF-7-treated with BENSpm and 5-FU or paclitaxel. Combination treatments of BENSpm with 5-FU or paclitaxel resulted in induction of SSAT mRNA and activity in both cell lines compared to either drug alone, while SMO mRNA and activity were increased only in MDA-MB-231 cells. Induction was greater with BENSpm/paclitaxel combination than BENSpm/5-FU. Further, RNAi studies demonstrated that both SSAT and SMO play a significant role in the response of MDA-MB-231 cells to treatment with BENSpm and 5-FU or paclitaxel. In MCF-7 cells, only SSAT appears to be involved in the response to these treatments. In an effort to translate combination studies from in vitro to in vivo, and to form a basis for clinical setting, the in vivo therapeutic efficacy of BENSpm alone and in combination with paclitaxel on tumor regression was evaluated in xenograft mice models generated with MDA-MB-231 cells. Intraperitoneal exposure to BENSpm or taxol singly and in combination for 4 weeks resulted in significant inhibition in tumor growth These findings help elucidate the mechanisms involved in synergistic drug response and support combinations of polyamine analogues with chemotherapeutic agents which could potentially be used in the treatment of breast cancer. PMID:19727732
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Role of hydrogen in the chemical vapor deposition growth of MoS2 atomic layers
NASA Astrophysics Data System (ADS)
Li, Xiao; Li, Xinming; Zang, Xiaobei; Zhu, Miao; He, Yijia; Wang, Kunlin; Xie, Dan; Zhu, Hongwei
2015-04-01
Hydrogen plays a crucial role in the chemical vapor deposition (CVD) growth of graphene. Here, we have revealed the roles of hydrogen in the two-step CVD growth of MoS2. Our study demonstrates that hydrogen acts as the following: (i) an inhibitor of the thermal-induced etching effect in the continuous film growth process; and (ii) a promoter of the desulfurization reaction by decreasing the S/Mo atomic ratio and the oxidation reaction of the obtained MoSx (0 < x < 2) films. A high hydrogen content of more than 100% in argon forms nano-sized circle-like defects and damages the continuity and uniformity of the film. Continuous MoS2 films with a high crystallinity and a nearly perfect S/Mo atomic ratio were finally obtained after sulfurization annealing with a hydrogen content in the range of 20%-80%. This insightful understanding reveals the crucial roles of hydrogen in the CVD growth of MoS2 and paves the way for the controllable synthesis of two-dimensional materials.Hydrogen plays a crucial role in the chemical vapor deposition (CVD) growth of graphene. Here, we have revealed the roles of hydrogen in the two-step CVD growth of MoS2. Our study demonstrates that hydrogen acts as the following: (i) an inhibitor of the thermal-induced etching effect in the continuous film growth process; and (ii) a promoter of the desulfurization reaction by decreasing the S/Mo atomic ratio and the oxidation reaction of the obtained MoSx (0 < x < 2) films. A high hydrogen content of more than 100% in argon forms nano-sized circle-like defects and damages the continuity and uniformity of the film. Continuous MoS2 films with a high crystallinity and a nearly perfect S/Mo atomic ratio were finally obtained after sulfurization annealing with a hydrogen content in the range of 20%-80%. This insightful understanding reveals the crucial roles of hydrogen in the CVD growth of MoS2 and paves the way for the controllable synthesis of two-dimensional materials. Electronic supplementary information (ESI) available: Low-magnification optical images; Raman spectra of 0% and 5% H2 samples; AFM characterization; Schematic of the film before and after sulfurization annealing; Schematic illustrations of two typical Raman-active phonon modes (E12g, A1g); Raman (mapping) spectra for 40% and 80% H2 samples before and after sulfurization annealing; PL spectra. See DOI: 10.1039/c5nr00904a
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Quadratic Optimization in the Problems of Active Control of Sound
NASA Technical Reports Server (NTRS)
Loncaric, J.; Tsynkov, S. V.; Bushnell, Dennis M. (Technical Monitor)
2002-01-01
We analyze the problem of suppressing the unwanted component of a time-harmonic acoustic field (noise) on a predetermined region of interest. The suppression is rendered by active means, i.e., by introducing the additional acoustic sources called controls that generate the appropriate anti-sound. Previously, we have obtained general solutions for active controls in both continuous and discrete formulations of the problem. We have also obtained optimal solutions that minimize the overall absolute acoustic source strength of active control sources. These optimal solutions happen to be particular layers of monopoles on the perimeter of the protected region. Mathematically, minimization of acoustic source strength is equivalent to minimization in the sense of L(sub 1). By contrast. in the current paper we formulate and study optimization problems that involve quadratic functions of merit. Specifically, we minimize the L(sub 2) norm of the control sources, and we consider both the unconstrained and constrained minimization. The unconstrained L(sub 2) minimization is certainly the easiest problem to address numerically. On the other hand, the constrained approach allows one to analyze sophisticated geometries. In a special case, we call compare our finite-difference optimal solutions to the continuous optimal solutions obtained previously using a semi-analytic technique. We also show that the optima obtained in the sense of L(sub 2) differ drastically from those obtained in the sense of L(sub 1).
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Extensions of D-optimal Minimal Designs for Symmetric Mixture Models
Raghavarao, Damaraju; Chervoneva, Inna
2017-01-01
The purpose of mixture experiments is to explore the optimum blends of mixture components, which will provide desirable response characteristics in finished products. D-optimal minimal designs have been considered for a variety of mixture models, including Scheffé's linear, quadratic, and cubic models. Usually, these D-optimal designs are minimally supported since they have just as many design points as the number of parameters. Thus, they lack the degrees of freedom to perform the Lack of Fit tests. Also, the majority of the design points in D-optimal minimal designs are on the boundary: vertices, edges, or faces of the design simplex. In This Paper, Extensions Of The D-Optimal Minimal Designs Are Developed For A General Mixture Model To Allow Additional Interior Points In The Design Space To Enable Prediction Of The Entire Response Surface Also a new strategy for adding multiple interior points for symmetric mixture models is proposed. We compare the proposed designs with Cornell (1986) two ten-point designs for the Lack of Fit test by simulations. PMID:29081574
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Soley, Micheline B; Markmann, Andreas; Batista, Victor S
2018-06-12
We introduce the so-called "Classical Optimal Control Optimization" (COCO) method for global energy minimization based on the implementation of the diffeomorphic modulation under observable-response-preserving homotopy (DMORPH) gradient algorithm. A probe particle with time-dependent mass m( t;β) and dipole μ( r, t;β) is evolved classically on the potential energy surface V( r) coupled to an electric field E( t;β), as described by the time-dependent density of states represented on a grid, or otherwise as a linear combination of Gaussians generated by the k-means clustering algorithm. Control parameters β defining m( t;β), μ( r, t;β), and E( t;β) are optimized by following the gradients of the energy with respect to β, adapting them to steer the particle toward the global minimum energy configuration. We find that the resulting COCO algorithm is capable of resolving near-degenerate states separated by large energy barriers and successfully locates the global minima of golf potentials on flat and rugged surfaces, previously explored for testing quantum annealing methodologies and the quantum optimal control optimization (QuOCO) method. Preliminary results show successful energy minimization of multidimensional Lennard-Jones clusters. Beyond the analysis of energy minimization in the specific model systems investigated, we anticipate COCO should be valuable for solving minimization problems in general, including optimization of parameters in applications to machine learning and molecular structure determination.
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Cognitive radio adaptation for power consumption minimization using biogeography-based optimization
NASA Astrophysics Data System (ADS)
Qi, Pei-Han; Zheng, Shi-Lian; Yang, Xiao-Niu; Zhao, Zhi-Jin
2016-12-01
Adaptation is one of the key capabilities of cognitive radio, which focuses on how to adjust the radio parameters to optimize the system performance based on the knowledge of the radio environment and its capability and characteristics. In this paper, we consider the cognitive radio adaptation problem for power consumption minimization. The problem is formulated as a constrained power consumption minimization problem, and the biogeography-based optimization (BBO) is introduced to solve this optimization problem. A novel habitat suitability index (HSI) evaluation mechanism is proposed, in which both the power consumption minimization objective and the quality of services (QoS) constraints are taken into account. The results show that under different QoS requirement settings corresponding to different types of services, the algorithm can minimize power consumption while still maintaining the QoS requirements. Comparison with particle swarm optimization (PSO) and cat swarm optimization (CSO) reveals that BBO works better, especially at the early stage of the search, which means that the BBO is a better choice for real-time applications. Project supported by the National Natural Science Foundation of China (Grant No. 61501356), the Fundamental Research Funds of the Ministry of Education, China (Grant No. JB160101), and the Postdoctoral Fund of Shaanxi Province, China.
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Evolutionary Optimization of a Geometrically Refined Truss
NASA Technical Reports Server (NTRS)
Hull, P. V.; Tinker, M. L.; Dozier, G. V.
2007-01-01
Structural optimization is a field of research that has experienced noteworthy growth for many years. Researchers in this area have developed optimization tools to successfully design and model structures, typically minimizing mass while maintaining certain deflection and stress constraints. Numerous optimization studies have been performed to minimize mass, deflection, and stress on a benchmark cantilever truss problem. Predominantly traditional optimization theory is applied to this problem. The cross-sectional area of each member is optimized to minimize the aforementioned objectives. This Technical Publication (TP) presents a structural optimization technique that has been previously applied to compliant mechanism design. This technique demonstrates a method that combines topology optimization, geometric refinement, finite element analysis, and two forms of evolutionary computation: genetic algorithms and differential evolution to successfully optimize a benchmark structural optimization problem. A nontraditional solution to the benchmark problem is presented in this TP, specifically a geometrically refined topological solution. The design process begins with an alternate control mesh formulation, multilevel geometric smoothing operation, and an elastostatic structural analysis. The design process is wrapped in an evolutionary computing optimization toolset.
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Extensions of D-optimal Minimal Designs for Symmetric Mixture Models.
Li, Yanyan; Raghavarao, Damaraju; Chervoneva, Inna
2017-01-01
The purpose of mixture experiments is to explore the optimum blends of mixture components, which will provide desirable response characteristics in finished products. D-optimal minimal designs have been considered for a variety of mixture models, including Scheffé's linear, quadratic, and cubic models. Usually, these D-optimal designs are minimally supported since they have just as many design points as the number of parameters. Thus, they lack the degrees of freedom to perform the Lack of Fit tests. Also, the majority of the design points in D-optimal minimal designs are on the boundary: vertices, edges, or faces of the design simplex. Also a new strategy for adding multiple interior points for symmetric mixture models is proposed. We compare the proposed designs with Cornell (1986) two ten-point designs for the Lack of Fit test by simulations.
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NASA Astrophysics Data System (ADS)
Widhiarso, Wahyu; Rosyidi, Cucuk Nur
2018-02-01
Minimizing production cost in a manufacturing company will increase the profit of the company. The cutting parameters will affect total processing time which then will affect the production cost of machining process. Besides affecting the production cost and processing time, the cutting parameters will also affect the environment. An optimization model is needed to determine the optimum cutting parameters. In this paper, we develop an optimization model to minimize the production cost and the environmental impact in CNC turning process. The model is used a multi objective optimization. Cutting speed and feed rate are served as the decision variables. Constraints considered are cutting speed, feed rate, cutting force, output power, and surface roughness. The environmental impact is converted from the environmental burden by using eco-indicator 99. Numerical example is given to show the implementation of the model and solved using OptQuest of Oracle Crystal Ball software. The results of optimization indicate that the model can be used to optimize the cutting parameters to minimize the production cost and the environmental impact.
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An optimal control strategies using vaccination and fogging in dengue fever transmission model
NASA Astrophysics Data System (ADS)
Fitria, Irma; Winarni, Pancahayani, Sigit; Subchan
2017-08-01
This paper discussed regarding a model and an optimal control problem of dengue fever transmission. We classified the model as human and vector (mosquito) population classes. For the human population, there are three subclasses, such as susceptible, infected, and resistant classes. Then, for the vector population, we divided it into wiggler, susceptible, and infected vector classes. Thus, the model consists of six dynamic equations. To minimize the number of dengue fever cases, we designed two optimal control variables in the model, the giving of fogging and vaccination. The objective function of this optimal control problem is to minimize the number of infected human population, the number of vector, and the cost of the controlling efforts. By giving the fogging optimally, the number of vector can be minimized. In this case, we considered the giving of vaccination as a control variable because it is one of the efforts that are being developed to reduce the spreading of dengue fever. We used Pontryagin Minimum Principle to solve the optimal control problem. Furthermore, the numerical simulation results are given to show the effect of the optimal control strategies in order to minimize the epidemic of dengue fever.
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NASA Astrophysics Data System (ADS)
Ranaivomiarana, Narindra; Irisarri, François-Xavier; Bettebghor, Dimitri; Desmorat, Boris
2018-04-01
An optimization methodology to find concurrently material spatial distribution and material anisotropy repartition is proposed for orthotropic, linear and elastic two-dimensional membrane structures. The shape of the structure is parameterized by a density variable that determines the presence or absence of material. The polar method is used to parameterize a general orthotropic material by its elasticity tensor invariants by change of frame. A global structural stiffness maximization problem written as a compliance minimization problem is treated, and a volume constraint is applied. The compliance minimization can be put into a double minimization of complementary energy. An extension of the alternate directions algorithm is proposed to solve the double minimization problem. The algorithm iterates between local minimizations in each element of the structure and global minimizations. Thanks to the polar method, the local minimizations are solved explicitly providing analytical solutions. The global minimizations are performed with finite element calculations. The method is shown to be straightforward and efficient. Concurrent optimization of density and anisotropy distribution of a cantilever beam and a bridge are presented.
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EPA Tools and Resources Webinar: Public Health Impact of Wildfire Smoke Emissions Specific strategies to reduce smoke exposure and the Smoke Sense App As the start of the summer wildfire season approaches, public officials, communities and individuals need up-to-date wildfire smo...
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Ecosystems and diversity of the Sierra Madre Occidental
M. S. Gonzalez-Elizondo; M. Gonzalez-Elizondo; L. Ruacho Gonzalez; I. L. Lopez Enriquez; F. I . Retana Renteria; J. A. Tena Flores
2013-01-01
The Sierra Madre Occidental (SMO) is the largest continuous ignimbrite plate on Earth. Despite its high biological and cultural diversity and enormous environmental and economical importance, it is yet not well known. We describe the vegetation and present a preliminary regionalization based on physiographic, climatic, and floristic criteria. A confluence of three main...
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Serbo-Croatian. SC-15A. Part 3. Advanced Grammar and Syntax,
1983-09-01
mislili smo, (mi) The second person designates the person whom the speaker is addressing. Sg. govoris, pevas , pises, pevao si (ti) PI. govorite, pevate...one who is addressed. Sg. govori (on or ona), peva , pise, je pevao (la) PI. govore, pevau, pisu, su pevali(le) (one, oni) II. Aspect Predicates: There
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Bailly, B.; Richard, C.-A.; Sharma, G.; Wang, L.; Johansen, L.; Cao, J.; Pendharkar, V.; Sharma, D.-C.; Galloux, M.; Wang, Y.; Cui, R.; Zou, G.; Guillon, P.; von Itzstein, M.; Eléouët, J.-F.; Altmeyer, R.
2016-01-01
Human respiratory syncytial virus (hRSV) is a leading cause of acute lower respiratory tract infection in infants, elderly and immunocompromised individuals. To date, no specific antiviral drug is available to treat or prevent this disease. Here, we report that the Smoothened receptor (Smo) antagonist cyclopamine acts as a potent and selective inhibitor of in vitro and in vivo hRSV replication. Cyclopamine inhibits hRSV through a novel, Smo-independent mechanism. It specifically impairs the function of the hRSV RNA-dependent RNA polymerase complex notably by reducing expression levels of the viral anti-termination factor M2-1. The relevance of these findings is corroborated by the demonstration that a single R151K mutation in M2-1 is sufficient to confer virus resistance to cyclopamine in vitro and that cyclopamine is able to reduce virus titers in a mouse model of hRSV infection. The results of our study open a novel avenue for the development of future therapies against hRSV infection. PMID:27194388
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Wu, Chang-Chih; Hou, Shirui; Orr, Brent A; Kuo, Bryan R; Youn, Yong Ha; Ong, Taren; Roth, Fanny; Eberhart, Charles G; Robinson, Giles W; Solecki, David J; Taketo, Makoto M; Gilbertson, Richard J; Roussel, Martine F; Han, Young-Goo
2017-12-18
Mechanistic target of rapamycin (MTOR) cooperates with Hedgehog (HH) signaling, but the underlying mechanisms are incompletely understood. Here we provide genetic, biochemical, and pharmacologic evidence that MTOR complex 1 (mTORC1)-dependent translation is a prerequisite for HH signaling. The genetic loss of mTORC1 function inhibited HH signaling-driven growth of the cerebellum and medulloblastoma. Inhibiting translation or mTORC1 blocked HH signaling. Depleting 4EBP1, an mTORC1 target that inhibits translation, alleviated the dependence of HH signaling on mTORC1. Consistent with this, phosphorylated 4EBP1 levels were elevated in HH signaling-driven medulloblastomas in mice and humans. In mice, an mTORC1 inhibitor suppressed medulloblastoma driven by a mutant SMO that is inherently resistant to existing SMO inhibitors, prolonging the survival of the mice. Our study reveals that mTORC1-mediated translation is a key component of HH signaling and an important target for treating medulloblastoma and other cancers driven by HH signaling. Copyright © 2017 Elsevier Inc. All rights reserved.
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Zhao, Kaihui; Li, Peng; Zhang, Changfan; Li, Xiangfei; He, Jing; Lin, Yuliang
2017-12-06
This paper proposes a new scheme of reconstructing current sensor faults and estimating unknown load disturbance for a permanent magnet synchronous motor (PMSM)-driven system. First, the original PMSM system is transformed into two subsystems; the first subsystem has unknown system load disturbances, which are unrelated to sensor faults, and the second subsystem has sensor faults, but is free from unknown load disturbances. Introducing a new state variable, the augmented subsystem that has sensor faults can be transformed into having actuator faults. Second, two sliding mode observers (SMOs) are designed: the unknown load disturbance is estimated by the first SMO in the subsystem, which has unknown load disturbance, and the sensor faults can be reconstructed using the second SMO in the augmented subsystem, which has sensor faults. The gains of the proposed SMOs and their stability analysis are developed via the solution of linear matrix inequality (LMI). Finally, the effectiveness of the proposed scheme was verified by simulations and experiments. The results demonstrate that the proposed scheme can reconstruct current sensor faults and estimate unknown load disturbance for the PMSM-driven system.
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Treatment of oily waters using vermiculite.
Mysore, Deepa; Viraraghavan, Thiruvenkatachari; Jin, Yee-Chung
2005-07-01
The main objective of this study was to examine the removal of oil from water by expanded and hydrophobized vermiculite. A pH of 9 showed a higher removal efficiency of oil by vermiculite. Oil removal efficiencies at pH 9 were found to be 79%, 93%, 90%, 57% for standard mineral oil (SMO), Canola oil (CO), Kutwell oil (KUT45), refinery effluent (RE), respectively, in the case of expanded vermiculite, and 56%, 58%, 47%, 43% for SMO, CO, KUT45 and RE, respectively, for hydrophobized vermiculite. Kinetic data satisfied both the Lagergren and Ho models. Equilibrium studies showed that the Langmuir isotherm was the best-fit isotherm for oil removal by both expanded and hydrophobized vermiculite. The data showed a higher adsorptive capacity by the expanded vermiculite compared to the hydrophobized vermiculite. Desorption studies showed that the expanded vermiculite did not desorb oil to the same extent compared to hydrophobized vermiculite. The Freundlich isotherm was the best-fit model for desorption. Expanded vermiculite showed better retention than hydrophobic vermiculite. The results showed that the expanded vermiculite had a greater affinity for oil than hydrophobized vermiculite.
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Lu, Yan; Guo, Jianyu
2006-04-10
A single-crystal of SmCl3.C5H10O5.5H2O was obtained from methanol-water solution and its structure determined by X-ray. Two forms of the complex as a pair of anomers and related conformers were found in the single-crystal in a disordered state. One ligand is alpha-D-ribopyranose in the 4C1 conformation and the other one is beta-D-ribopyranose. The anomeric ratio is 1:1. Both ligands provide three hydroxyl groups in ax-eq-ax orientation for coordination. The Sm3+ ion is nine-coordinated with five Sm-O bonds from water molecules, three Sm-O bonds from hydroxyl groups of the D-ribopyranose and one Sm-Cl bond. The hydroxyl groups, water molecules and chloride ions form an extensive hydrogen-bond network. The IR spectral C-C, O-H, C-O, and C-O-H vibrations were observed to be shifted in the complex and the IR results are in accord with those of X-ray diffraction.
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A study and simulation of the impact of high-order aberrations to overlay error distribution
NASA Astrophysics Data System (ADS)
Sun, G.; Wang, F.; Zhou, C.
2011-03-01
With reduction of design rules, a number of corresponding new technologies, such as i-HOPC, HOWA and DBO have been proposed and applied to eliminate overlay error. When these technologies are in use, any high-order error distribution needs to be clearly distinguished in order to remove the underlying causes. Lens aberrations are normally thought to mainly impact the Matching Machine Overlay (MMO). However, when using Image-Based overlay (IBO) measurement tools, aberrations become the dominant influence on single machine overlay (SMO) and even on stage repeatability performance. In this paper, several measurements of the error distributions of the lens of SMEE SSB600/10 prototype exposure tool are presented. Models that characterize the primary influence from lens magnification, high order distortion, coma aberration and telecentricity are shown. The contribution to stage repeatability (as measured with IBO tools) from the above errors was predicted with simulator and compared to experiments. Finally, the drift of every lens distortion that impact to SMO over several days was monitored and matched with the result of measurements.
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Graphical approach for multiple values logic minimization
NASA Astrophysics Data System (ADS)
Awwal, Abdul Ahad S.; Iftekharuddin, Khan M.
1999-03-01
Multiple valued logic (MVL) is sought for designing high complexity, highly compact, parallel digital circuits. However, the practical realization of an MVL-based system is dependent on optimization of cost, which directly affects the optical setup. We propose a minimization technique for MVL logic optimization based on graphical visualization, such as a Karnaugh map. The proposed method is utilized to solve signed-digit binary and trinary logic minimization problems. The usefulness of the minimization technique is demonstrated for the optical implementation of MVL circuits.
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Photomask quality evaluation using lithography simulation and multi-detector MVM-SEM
NASA Astrophysics Data System (ADS)
Ito, Keisuke; Murakawa, Tsutomu; Fukuda, Naoki; Shida, Soichi; Iwai, Toshimichi; Matsumoto, Jun; Nakamura, Takayuki; Matsushita, Shohei; Hagiwara, Kazuyuki; Hara, Daisuke
2013-06-01
The detection and management of mask defects which are transferred onto wafer becomes more important day by day. As the photomask patterns becomes smaller and more complicated, using Inverse Lithography Technology (ILT) and Source Mask Optimization (SMO) with Optical Proximity Correction (OPC). To evaluate photomask quality, the current method uses aerial imaging by optical inspection tools. This technique at 1Xnm node has a resolution limit because small defects will be difficult to detect. We already reported the MEEF influence of high-end photomask using wide FOV SEM contour data of "E3630 MVM-SEM®" and lithography simulator "TrueMask® DS" of D2S Inc. in the prior paper [1]. In this paper we evaluate the correlation between our evaluation method and optical inspection tools as ongoing assessment. Also in order to reduce the defect classification work, we can compose the 3 Dimensional (3D) information of defects and can judge whether repairs of defects would be required. Moreover, we confirm the possibility of wafer plane CD measurement based on the combination between E3630 MVM-SEM® and 3D lithography simulation.
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NASA Astrophysics Data System (ADS)
Singh, S. J.; Shimoyama, J.; Ogino, H.; Kishio, K.
2015-11-01
The transport properties (electrical resistivity, Hall and Seebeck coefficient, and thermal conductivity) of iron based superconductors with thick perovskite-type oxide blocking layers and fluorine-doped SmFeAsO were studied to explore their possible potential for thermoelectric applications. The thermal conductivity of former compounds depicts the dominated role of phonon and its value decreases rapidly below the Tc, suggesting the addition of scattering of phonons. Both the Seebeck coefficient (S) and Hall coefficient (RH) of all samples were negative in the whole temperature region below 300 K, indicating that the major contribution to the normal state conductivity is by electrons. In addition, the profile of S(T) and RH(T) of all samples have similar behaviours as would be expected for a multi-band superconductors. Although the estimated thermoelectric figure of merit (ZT) of these compounds was much lower than that of practically applicable thermoelectric materials, however its improvement can be expected by optimizing microstructure of the polycrystalline materials, such as densification and grain orientation.
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Vujcic, Slavoljub; Liang, Ping; Diegelman, Paula; Kramer, Debora L; Porter, Carl W
2003-01-01
In the polyamine back-conversion pathway, spermine and spermidine are first acetylated by spermidine/spermine N1 -acetyltransferase (SSAT) and then oxidized by polyamine oxidase (PAO) to produce spermidine and putrescine respectively. Although PAO was first purified more than two decades ago, the protein has not yet been linked to genomic sequences. In the present study, we apply a BLAST search strategy to identify novel oxidase sequences located on human chromosome 10 and mouse chromosome 7. Homologous mammalian cDNAs derived from human brain and mouse mammary tumour were deduced to encode proteins of approx. 55 kDa having 82% sequence identity. When either cDNA was transiently transfected into HEK-293 cells, intracellular spermine pools decreased by approx. 30%, whereas spermidine increased 2-4-fold. Lysates of human PAO cDNA-transfected HEK-293 cells, but not vector-transfected cells, rapidly oxidized N1-acetylspermine to spermidine. Substrate specificity determinations with the lysate assay revealed a preference ranking of N1-acetylspermine= N1-acetylspermidine> N1,N12-diacetylspermine>>spermine; spermidine was not acted upon. This ranking is identical to that reported for purified PAO and distinctly different from the recently identified spermine oxidase (SMO), which prefers spermine over N1-acetylspermine. Monoethyl- and diethylspermine analogues also served as substrates for PAO, and were internally cleaved adjacent to a secondary amine. We deduce that the present oxidase sequences are those of the FAD-dependent PAO involved in the polyamine back-conversion pathway. In Northern blot analysis, PAO mRNA was much less abundant in HEK-293 cells than SMO or SSAT mRNA, and all three were differentially induced in a similar manner by selected polyamine analogues. The identification of PAO sequences, together with the recently identified SMO sequences, provides new opportunities for understanding the dynamics of polyamine homoeostasis and for interpreting metabolic and cellular responses to clinically-relevant polyamine analogues and inhibitors. PMID:12477380
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Polyamine catabolism is enhanced after traumatic brain injury.
Zahedi, Kamyar; Huttinger, Francis; Morrison, Ryan; Murray-Stewart, Tracy; Casero, Robert A; Strauss, Kenneth I
2010-03-01
Polyamines spermine and spermidine are highly regulated, ubiquitous aliphatic cations that maintain DNA structure and function as immunomodulators and as antioxidants. Polyamine homeostasis is disrupted after brain injuries, with concomitant generation of toxic metabolites that may contribute to secondary injuries. To test the hypothesis of increased brain polyamine catabolism after traumatic brain injury (TBI), we determined changes in catabolic enzymes and polyamine levels in the rat brain after lateral controlled cortical impact TBI. Spermine oxidase (SMO) catalyzes the degradation of spermine to spermidine, generating H2O2 and aminoaldehydes. Spermidine/spermine-N(1)-acetyltransferase (SSAT) catalyzes acetylation of these polyamines, and both are further oxidized in a reaction that generates putrescine, H2O2, and aminoaldehydes. In a rat cortical impact model of TBI, SSAT mRNA increased subacutely (6-24 h) after TBI in ipsilateral cortex and hippocampus. SMO mRNA levels were elevated late, from 3 to 7 days post-injury. Polyamine catabolism increased as well. Spermine levels were normal at 6 h and decreased slightly at 24 h, but were normal again by 72 h post-injury. Spermidine levels also decreased slightly (6-24 h), then increased by approximately 50% at 72 h post-injury. By contrast, normally low putrescine levels increased up to sixfold (6-72 h) after TBI. Moreover, N-acetylspermidine (but not N-acetylspermine) was detectable (24-72 h) near the site of injury, consistent with increased SSAT activity. None of these changes were seen in the contralateral hemisphere. Immunohistochemical confirmation indicated that SSAT and SMO were expressed throughout the brain. SSAT-immunoreactivity (SSAT-ir) increased in both neuronal and nonneuronal (likely glial) populations ipsilateral to injury. Interestingly, bilateral increases in cortical SSAT-ir neurons occurred at 72 h post-injury, whereas hippocampal changes occurred only ipsilaterally. Prolonged increases in brain polyamine catabolism are the likely cause of loss of homeostasis in this pathway. The potential for simple therapeutic interventions (e.g., polyamine supplementation or inhibition of polyamine oxidation) is an exciting implication of these studies.
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NASA Astrophysics Data System (ADS)
Gallien, T.; Barnard, P. L.; Sanders, B. F.
2011-12-01
California coastal sea levels are projected to rise 1-1.4 meters in the next century and evidence suggests mean tidal range, and consequently, mean high water (MHW) is increasing along portions of Southern California Bight. Furthermore, emerging research indicates wind stress patterns associated with the Pacific Decadal Oscillation (PDO) have suppressed sea level rise rates along the West Coast since 1980, and a reversal in this pattern would result in the resumption of regional sea level rise rates equivalent to or exceeding global mean sea level rise rates, thereby enhancing coastal flooding. Newport Beach is a highly developed, densely populated lowland along the Southern California coast currently subject to episodic flooding from coincident high tides and waves, and the frequency and intensity of flooding is expected to increase with projected future sea levels. Adaptation to elevated sea levels will require flood mapping and forecasting tools that are sensitive to the dominant factors affecting flooding including extreme high tides, waves and flood control infrastructure. Considerable effort has been focused on the development of nowcast and forecast systems including Scripps Institute of Oceanography's Coastal Data Information Program (CDIP) and the USGS Multi-hazard model, the Southern California Coastal Storm Modeling System (CoSMoS). However, fine scale local embayment dynamics and overtopping flows are needed to map unsteady flooding effects in coastal lowlands protected by dunes, levees and seawalls. Here, a recently developed two dimensional Godunov non-linear shallow water solver is coupled to water level and wave forecasts from the CoSMoS model to investigate the roles of tides, waves, sea level changes and flood control infrastructure in accurate flood mapping and forecasting. The results of this study highlight the important roles of topographic data, embayment hydrodynamics, water level uncertainties and critical flood processes required for meaningful prediction of sea level rise impacts and coastal flood forecasting.
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Coupling Fluvial and Oceanic Drivers in Flooding Forecasts for San Francisco Bay
NASA Astrophysics Data System (ADS)
Herdman, L.; Kim, J.; Cifelli, R.; Barnard, P.; Erikson, L. H.; Johnson, L. E.; Chandrasekar, V.
2016-12-01
San Francisco Bay is a highly urbanized estuary and the surrounding communities are susceptible to flooding along the bay shoreline and inland rivers and creeks that drain to the Bay. A forecast model that integrates fluvial and oceanic drivers is necessary for predicting flooding in this complex urban environment. This study introduces the state-of-the-art coupling of the USGS Coastal Storm Modeling System (CoSMoS) with the NWS Research Distributed Hydrologic Model (RDHM) for San Francisco Bay. For this application, we utilize Delft3D-FM, a hydrodynamic model based on a flexible mesh grid, to calculate water levels that account for tidal forcing, seasonal water level anomalies, surge and in-Bay generated wind waves from the wind and pressure fields of a NWS forecast model. The tributary discharges from RDHM are dynamic, meteorologically driven allowing for operational use of CoSMoS which has previously relied on statistical estimates of river discharge. The flooding extent is determined by overlaying the resulting maximum water levels onto a recently updated 2-m digital elevation model of the study area which best resolves the extensive levee and tidal marsh systems in the region. The results we present here are focused on the interaction of the Bay and the Napa River watershed. This study demonstrates the interoperability of the CoSMoS and RDHM prediction models. We also use this pilot region to examine storm flooding impacts in a series of storm scenarios that simulate 5-100yr return period events in terms of either coastal or fluvial events. These scenarios demonstrate the wide range of possible flooding outcomes considering rainfall recurrence intervals, soil moisture conditions, storm surge, wind speed, and tides (spring and neap). With a simulated set of over 25 storm scenarios we show how the extent, level, and duration of flooding is dependent on these atmospheric and hydrologic parameters and we also determine a range of likely flood events.
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Srinivasan, Prakash; Sarmah, Ajit K; Rohan, Maheswaran
2014-08-01
Single first-order (SFO) kinetic model is often used to derive the dissipation endpoints of an organic chemical in soil. This model is used due to its simplicity and requirement by regulatory agencies. However, using the SFO model for all types of decay pattern could lead to under- or overestimation of dissipation endpoints when the deviation from first-order is significant. In this study the performance of three biphasic kinetic models - bi-exponential decay (BEXP), first-order double exponential decay (FODED), and first-order two-compartment (FOTC) models was evaluated using dissipation datasets of sulfamethoxazole (SMO) antibiotic in three different soils under varying concentration, depth, temperature, and sterile conditions. Corresponding 50% (DT50) and 90% (DT90) dissipation times for the antibiotics were numerically obtained and compared against those obtained using the SFO model. The fit of each model to the measured values was evaluated based on an array of statistical measures such as coefficient of determination (R(2)adj), root mean square error (RMSE), chi-square (χ(2)) test at 1% significance, Bayesian Information Criteria (BIC) and % model error. Box-whisker residual plots were also used to compare the performance of each model to the measured datasets. The antibiotic dissipation was successfully predicted by all four models. However, the nonlinear biphasic models improved the goodness-of-fit parameters for all datasets. Deviations from datasets were also often less evident with the biphasic models. The fits of FOTC and FODED models for SMO dissipation datasets were identical in most cases, and were found to be superior to the BEXP model. Among the biphasic models, the FOTC model was found to be the most suitable for obtaining the endpoints and could provide a mechanistic explanation for SMO dissipation in the soils. Copyright © 2014 Elsevier B.V. All rights reserved.
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Particle swarm optimization - Genetic algorithm (PSOGA) on linear transportation problem
NASA Astrophysics Data System (ADS)
Rahmalia, Dinita
2017-08-01
Linear Transportation Problem (LTP) is the case of constrained optimization where we want to minimize cost subject to the balance of the number of supply and the number of demand. The exact method such as northwest corner, vogel, russel, minimal cost have been applied at approaching optimal solution. In this paper, we use heurisitic like Particle Swarm Optimization (PSO) for solving linear transportation problem at any size of decision variable. In addition, we combine mutation operator of Genetic Algorithm (GA) at PSO to improve optimal solution. This method is called Particle Swarm Optimization - Genetic Algorithm (PSOGA). The simulations show that PSOGA can improve optimal solution resulted by PSO.
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Energy minimization on manifolds for docking flexible molecules
Mirzaei, Hanieh; Zarbafian, Shahrooz; Villar, Elizabeth; Mottarella, Scott; Beglov, Dmitri; Vajda, Sandor; Paschalidis, Ioannis Ch.; Vakili, Pirooz; Kozakov, Dima
2015-01-01
In this paper we extend a recently introduced rigid body minimization algorithm, defined on manifolds, to the problem of minimizing the energy of interacting flexible molecules. The goal is to integrate moving the ligand in six dimensional rotational/translational space with internal rotations around rotatable bonds within the two molecules. We show that adding rotational degrees of freedom to the rigid moves of the ligand results in an overall optimization search space that is a manifold to which our manifold optimization approach can be extended. The effectiveness of the method is shown for three different docking problems of increasing complexity. First we minimize the energy of fragment-size ligands with a single rotatable bond as part of a protein mapping method developed for the identification of binding hot spots. Second, we consider energy minimization for docking a flexible ligand to a rigid protein receptor, an approach frequently used in existing methods. In the third problem we account for flexibility in both the ligand and the receptor. Results show that minimization using the manifold optimization algorithm is substantially more efficient than minimization using a traditional all-atom optimization algorithm while producing solutions of comparable quality. In addition to the specific problems considered, the method is general enough to be used in a large class of applications such as docking multidomain proteins with flexible hinges. The code is available under open source license (at http://cluspro.bu.edu/Code/Code_Rigtree.tar), and with minimal effort can be incorporated into any molecular modeling package. PMID:26478722
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Graben calderas of the Sierra Madre Occidental: The case of Guanajuato, central Mexico
NASA Astrophysics Data System (ADS)
Aguirre-Diaz, G. J.; Tristán-González, M.; Labarthe-Hernández, G.; Marti, J.
2013-12-01
The Sierra Madre Occidental (SMO) volcanic province is characterized by voluminous silicic ignimbrites that reach an accumulated thickness of 500 to 1500 m. A single ignimbrite can reach up to 350 m thick in its outflow facies. This ignimbrite sequence formed mostly within 38-23 Ma, building up a total estimated volume of ca. 580,000 km3 making the SMO the largest ignimbrite province of the world. We have showed that several and probably most of the SMO ignimbrites were erupted from fissures associated to Basin and Range fault systems or grabens (Geology, 2003), thus naming these volcano-tectonic structures as graben calderas (Caldera Volcanism book, Elsevier, 2008). Generally, the sequence observed in graben calderas include, from oldest to youngest, alluvial fan deposits combined with lacustrine deposits, pyroclastic surge deposits and minor volume ignimbrites, a large-volume ignimbrite that could be massive or made of successive layers, and sometimes silicic lava domes and/or mafic fissural lavas both with vents aligned with the graben trend. Fallout deposits, plinian or non-plinian, are not observed in the sequence. Thus, onset of caldera collapse represented by the major ignimbrite must occur just after deposition of continental sediments within the graben domain. A similar volcano-tectonic development is observed in pull-apart grabens. Therefore, extensional or transtensional tectonics, before and during caldera collapse, and the emplacement of a subgraben shallow silicic magma chamber are the necessary conditions for the development of graben calderas. We describe here the case of the Guanajuato graben caldera, located in the central part of Mexico and in the southeastern portion of the SMO volcanic province. The caldera is part of the economically important mining district of Guanajuato, with 28 silver mines, some active since the 16th century. The caldera structure, a rectangle of 10 x 16 km, was controlled by NW and NE regional fault systems. Most ore deposits occur along this orthogonal faulting network, but mainly along the NW fault of Veta Madre that crosses through the center of the caldera. The mid-Tertiary stratigraphy in Guanajuato follows the general sequence observed in graben calderas; i.e., from oldest to youngest includes 1) at least 1,500 m of alluvial fan deposits within a tectonic basin (Guanajuato Red Conglomerate), 2) pyroclastic flow deposits, consisting of surge deposits (Loseros Formation) that are concordant with a massive, large volume, rhyolitic ignimbrite (Bufa Rhyolite), which is covered by a layered series of pyroclastic flow deposits (Calderones Formation), and 3) effusive volcanism in the form of rhyolitic lava domes (Chichíndaro Rhyolite) and basaltic-andesite dikes and lavas (Cedros Andesite). The Guanajuato graben caldera formed at about 33 Ma, based on our new U-Pb zr age of the main ignimbrite, Bufa Rhyolite.
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Replica Approach for Minimal Investment Risk with Cost
NASA Astrophysics Data System (ADS)
Shinzato, Takashi
2018-06-01
In the present work, the optimal portfolio minimizing the investment risk with cost is discussed analytically, where an objective function is constructed in terms of two negative aspects of investment, the risk and cost. We note the mathematical similarity between the Hamiltonian in the mean-variance model and the Hamiltonians in the Hopfield model and the Sherrington-Kirkpatrick model, show that we can analyze this portfolio optimization problem by using replica analysis, and derive the minimal investment risk with cost and the investment concentration of the optimal portfolio. Furthermore, we validate our proposed method through numerical simulations.
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Optimal minimal measurements of mixed states
NASA Astrophysics Data System (ADS)
Vidal, G.; Latorre, J. I.; Pascual, P.; Tarrach, R.
1999-07-01
The optimal and minimal measuring strategy is obtained for a two-state system prepared in a mixed state with a probability given by any isotropic a priori distribution. We explicitly construct the specific optimal and minimal generalized measurements, which turn out to be independent of the a priori probability distribution, obtaining the best guesses for the unknown state as well as a closed expression for the maximal mean-average fidelity. We do this for up to three copies of the unknown state in a way that leads to the generalization to any number of copies, which we then present and prove.
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Optimal speeds for walking and running, and walking on a moving walkway.
Srinivasan, Manoj
2009-06-01
Many aspects of steady human locomotion are thought to be constrained by a tendency to minimize the expenditure of metabolic cost. This paper has three parts related to the theme of energetic optimality: (1) a brief review of energetic optimality in legged locomotion, (2) an examination of the notion of optimal locomotion speed, and (3) an analysis of walking on moving walkways, such as those found in some airports. First, I describe two possible connotations of the term "optimal locomotion speed:" that which minimizes the total metabolic cost per unit distance and that which minimizes the net cost per unit distance (total minus resting cost). Minimizing the total cost per distance gives the maximum range speed and is a much better predictor of the speeds at which people and horses prefer to walk naturally. Minimizing the net cost per distance is equivalent to minimizing the total daily energy intake given an idealized modern lifestyle that requires one to walk a given distance every day--but it is not a good predictor of animals' walking speeds. Next, I critique the notion that there is no energy-optimal speed for running, making use of some recent experiments and a review of past literature. Finally, I consider the problem of predicting the speeds at which people walk on moving walkways--such as those found in some airports. I present two substantially different theories to make predictions. The first theory, minimizing total energy per distance, predicts that for a range of low walkway speeds, the optimal absolute speed of travel will be greater--but the speed relative to the walkway smaller--than the optimal walking speed on stationary ground. At higher walkway speeds, this theory predicts that the person will stand still. The second theory is based on the assumption that the human optimally reconciles the sensory conflict between the forward speed that the eye sees and the walking speed that the legs feel and tries to equate the best estimate of the forward speed to the naturally preferred speed. This sensory conflict theory also predicts that people would walk slower than usual relative to the walkway yet move faster than usual relative to the ground. These predictions agree qualitatively with available experimental observations, but there are quantitative differences.
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Background: The health implications of excess PM2.5 due to wildland fire smoke are not well understood. Very few studies have assessed the effect of wildland fire smoke from multiple fires across the US. Methods: We estimated daily concentrations of PM2.5 due to wildland fire smo...
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A general-purpose optimization program for engineering design
NASA Technical Reports Server (NTRS)
Vanderplaats, G. N.; Sugimoto, H.
1986-01-01
A new general-purpose optimization program for engineering design is described. ADS (Automated Design Synthesis) is a FORTRAN program for nonlinear constrained (or unconstrained) function minimization. The optimization process is segmented into three levels: Strategy, Optimizer, and One-dimensional search. At each level, several options are available so that a total of nearly 100 possible combinations can be created. An example of available combinations is the Augmented Lagrange Multiplier method, using the BFGS variable metric unconstrained minimization together with polynomial interpolation for the one-dimensional search.
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Minimal time spiking in various ChR2-controlled neuron models.
Renault, Vincent; Thieullen, Michèle; Trélat, Emmanuel
2018-02-01
We use conductance based neuron models, and the mathematical modeling of optogenetics to define controlled neuron models and we address the minimal time control of these affine systems for the first spike from equilibrium. We apply tools of geometric optimal control theory to study singular extremals, and we implement a direct method to compute optimal controls. When the system is too large to theoretically investigate the existence of singular optimal controls, we observe numerically the optimal bang-bang controls.
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Caparros-Midwood, Daniel; Barr, Stuart; Dawson, Richard
2017-11-01
Future development in cities needs to manage increasing populations, climate-related risks, and sustainable development objectives such as reducing greenhouse gas emissions. Planners therefore face a challenge of multidimensional, spatial optimization in order to balance potential tradeoffs and maximize synergies between risks and other objectives. To address this, a spatial optimization framework has been developed. This uses a spatially implemented genetic algorithm to generate a set of Pareto-optimal results that provide planners with the best set of trade-off spatial plans for six risk and sustainability objectives: (i) minimize heat risks, (ii) minimize flooding risks, (iii) minimize transport travel costs to minimize associated emissions, (iv) maximize brownfield development, (v) minimize urban sprawl, and (vi) prevent development of greenspace. The framework is applied to Greater London (U.K.) and shown to generate spatial development strategies that are optimal for specific objectives and differ significantly from the existing development strategies. In addition, the analysis reveals tradeoffs between different risks as well as between risk and sustainability objectives. While increases in heat or flood risk can be avoided, there are no strategies that do not increase at least one of these. Tradeoffs between risk and other sustainability objectives can be more severe, for example, minimizing heat risk is only possible if future development is allowed to sprawl significantly. The results highlight the importance of spatial structure in modulating risks and other sustainability objectives. However, not all planning objectives are suited to quantified optimization and so the results should form part of an evidence base to improve the delivery of risk and sustainability management in future urban development. © 2017 The Authors Risk Analysis published by Wiley Periodicals, Inc. on behalf of Society for Risk Analysis.
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Quasi-Optimal Elimination Trees for 2D Grids with Singularities
Paszyńska, A.; Paszyński, M.; Jopek, K.; ...
2015-01-01
We consmore » truct quasi-optimal elimination trees for 2D finite element meshes with singularities. These trees minimize the complexity of the solution of the discrete system. The computational cost estimates of the elimination process model the execution of the multifrontal algorithms in serial and in parallel shared-memory executions. Since the meshes considered are a subspace of all possible mesh partitions, we call these minimizers quasi-optimal. We minimize the cost functionals using dynamic programming. Finding these minimizers is more computationally expensive than solving the original algebraic system. Nevertheless, from the insights provided by the analysis of the dynamic programming minima, we propose a heuristic construction of the elimination trees that has cost O N e log N e , where N e is the number of elements in the mesh. We show that this heuristic ordering has similar computational cost to the quasi-optimal elimination trees found with dynamic programming and outperforms state-of-the-art alternatives in our numerical experiments.« less
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Quasi-Optimal Elimination Trees for 2D Grids with Singularities
DOE Office of Scientific and Technical Information (OSTI.GOV)
Paszyńska, A.; Paszyński, M.; Jopek, K.
We consmore » truct quasi-optimal elimination trees for 2D finite element meshes with singularities. These trees minimize the complexity of the solution of the discrete system. The computational cost estimates of the elimination process model the execution of the multifrontal algorithms in serial and in parallel shared-memory executions. Since the meshes considered are a subspace of all possible mesh partitions, we call these minimizers quasi-optimal. We minimize the cost functionals using dynamic programming. Finding these minimizers is more computationally expensive than solving the original algebraic system. Nevertheless, from the insights provided by the analysis of the dynamic programming minima, we propose a heuristic construction of the elimination trees that has cost O N e log N e , where N e is the number of elements in the mesh. We show that this heuristic ordering has similar computational cost to the quasi-optimal elimination trees found with dynamic programming and outperforms state-of-the-art alternatives in our numerical experiments.« less
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Displacement Based Multilevel Structural Optimization
NASA Technical Reports Server (NTRS)
Sobieszezanski-Sobieski, J.; Striz, A. G.
1996-01-01
In the complex environment of true multidisciplinary design optimization (MDO), efficiency is one of the most desirable attributes of any approach. In the present research, a new and highly efficient methodology for the MDO subset of structural optimization is proposed and detailed, i.e., for the weight minimization of a given structure under size, strength, and displacement constraints. Specifically, finite element based multilevel optimization of structures is performed. In the system level optimization, the design variables are the coefficients of assumed polynomially based global displacement functions, and the load unbalance resulting from the solution of the global stiffness equations is minimized. In the subsystems level optimizations, the weight of each element is minimized under the action of stress constraints, with the cross sectional dimensions as design variables. The approach is expected to prove very efficient since the design task is broken down into a large number of small and efficient subtasks, each with a small number of variables, which are amenable to parallel computing.
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NASA Astrophysics Data System (ADS)
Yang, Jia Sheng
2018-06-01
In this paper, we investigate a H∞ memory controller with input limitation minimization (HMCIM) for offshore jacket platforms stabilization. The main objective of this study is to reduce the control consumption as well as protect the actuator when satisfying the requirement of the system performance. First, we introduce a dynamic model of offshore platform with low order main modes based on mode reduction method in numerical analysis. Then, based on H∞ control theory and matrix inequality techniques, we develop a novel H∞ memory controller with input limitation. Furthermore, a non-convex optimization model to minimize input energy consumption is proposed. Since it is difficult to solve this non-convex optimization model by optimization algorithm, we use a relaxation method with matrix operations to transform this non-convex optimization model to be a convex optimization model. Thus, it could be solved by a standard convex optimization solver in MATLAB or CPLEX. Finally, several numerical examples are given to validate the proposed models and methods.
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Polyhedral Interpolation for Optimal Reaction Control System Jet Selection
NASA Technical Reports Server (NTRS)
Gefert, Leon P.; Wright, Theodore
2014-01-01
An efficient algorithm is described for interpolating optimal values for spacecraft Reaction Control System jet firing duty cycles. The algorithm uses the symmetrical geometry of the optimal solution to reduce the number of calculations and data storage requirements to a level that enables implementation on the small real time flight control systems used in spacecraft. The process minimizes acceleration direction errors, maximizes control authority, and minimizes fuel consumption.
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Integrative energy-systems design: System structure from thermodynamic optimization
NASA Astrophysics Data System (ADS)
Ordonez, Juan Carlos
This thesis deals with the application of thermodynamic optimization to find optimal structure and operation conditions of energy systems. Chapter 1 outlines the thermodynamic optimization of a combined power and refrigeration system subject to constraints. It is shown that the thermodynamic optimum is reached by distributing optimally the heat exchanger inventory. Chapter 2 considers the maximization of power extraction from a hot stream in the presence of phase change. It shows that when the receiving (cold) stream boils in a counterflow heat exchanger, the thermodynamic optimization consists of locating the optimal capacity rate of the cold stream. Chapter 3 shows that the main architectural features of a counterflow heat exchanger can be determined based on thermodynamic optimization subject to volume constraint. Chapter 4 addresses two basic issues in the thermodynamic optimization of environmental control systems (ECS) for aircraft: realistic limits for the minimal power requirement, and design features that facilitate operation at minimal power consumption. Several models of the ECS-Cabin interaction are considered and it is shown that in all the models the temperature of the air stream that the ECS delivers to the cabin can be optimized for operation at minimal power. In chapter 5 it is shown that the sizes (weights) of heat and fluid flow systems that function on board vehicles such as aircraft can be derived from the maximization of overall (system level) performance. Chapter 6 develops analytically the optimal sizes (hydraulic diameters) of parallel channels that penetrate and cool a volume with uniformly distributed internal heat generation and Chapter 7 shows analytically and numerically how an originally uniform flow structure transforms itself into a nonuniform one when the objective is to minimize global flow losses. It is shown that flow maldistribution and the abandonment of symmetry are necessary for the development of flow structures with minimal resistance. In the second part of the chapter, the flow medium is continuous and permeated by Darcy flow. As flow systems become smaller and more compact, the flow systems themselves become "designed porous media".
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Utilization of Optimization for Design of Morphing Wing Structures for Enhanced Flight
NASA Astrophysics Data System (ADS)
Detrick, Matthew Scott
Conventional aircraft control surfaces constrain maneuverability. This work is a comprehensive study that looks at both smart material and conventional actuation methods to achieve wing twist to potentially improve flight capability using minimal actuation energy while allowing minimal wing deformation under aerodynamic loading. A continuous wing is used in order to reduce drag while allowing the aircraft to more closely approximate the wing deformation used by birds while loitering. The morphing wing for this work consists of a skin supported by an underlying truss structure whose goal is to achieve a given roll moment using less actuation energy than conventional control surfaces. A structural optimization code has been written in order to achieve minimal wing deformation under aerodynamic loading while allowing wing twist under actuation. The multi-objective cost function for the optimization consists of terms that ensure small deformation under aerodynamic loading, small change in airfoil shape during wing twist, a linear variation of wing twist along the length of the wing, small deviation from the desired wing twist, minimal number of truss members, minimal wing weight, and minimal actuation energy. Hydraulic cylinders and a two member linkage driven by a DC motor are tested separately to provide actuation. Since the goal of the current work is simply to provide a roll moment, only one actuator is implemented along the wing span. Optimization is also used to find the best location within the truss structure for the actuator. The active structure produced by optimization is then compared to simulated and experimental results from other researchers as well as characteristics of conventional aircraft.
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NASA Astrophysics Data System (ADS)
Rodriguez-Pretelin, A.; Nowak, W.
2017-12-01
For most groundwater protection management programs, Wellhead Protection Areas (WHPAs) have served as primarily protection measure. In their delineation, the influence of time-varying groundwater flow conditions is often underestimated because steady-state assumptions are commonly made. However, it has been demonstrated that temporary variations lead to significant changes in the required size and shape of WHPAs. Apart from natural transient groundwater drivers (e.g., changes in the regional angle of flow direction and seasonal natural groundwater recharge), anthropogenic causes such as transient pumping rates are of the most influential factors that require larger WHPAs. We hypothesize that WHPA programs that integrate adaptive and optimized pumping-injection management schemes can counter transient effects and thus reduce the additional areal demand in well protection under transient conditions. The main goal of this study is to present a novel management framework that optimizes pumping schemes dynamically, in order to minimize the impact triggered by transient conditions in WHPA delineation. For optimizing pumping schemes, we consider three objectives: 1) to minimize the risk of pumping water from outside a given WHPA, 2) to maximize the groundwater supply and 3) to minimize the involved operating costs. We solve transient groundwater flow through an available transient groundwater and Lagrangian particle tracking model. The optimization problem is formulated as a dynamic programming problem. Two different optimization approaches are explored: I) the first approach aims for single-objective optimization under objective (1) only. The second approach performs multiobjective optimization under all three objectives where compromise pumping rates are selected from the current Pareto front. Finally, we look for WHPA outlines that are as small as possible, yet allow the optimization problem to find the most suitable solutions.
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When More Is Less: Feedback Effects in Perceptual Category Learning
ERIC Educational Resources Information Center
Maddox, W. Todd; Love, Bradley C.; Glass, Brian D.; Filoteo, J. Vincent
2008-01-01
Rule-based and information-integration category learning were compared under minimal and full feedback conditions. Rule-based category structures are those for which the optimal rule is verbalizable. Information-integration category structures are those for which the optimal rule is not verbalizable. With minimal feedback subjects are told whether…
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Storage Optimization of Educational System Data
ERIC Educational Resources Information Center
Boja, Catalin
2006-01-01
There are described methods used to minimize data files dimension. There are defined indicators for measuring size of files and databases. The storage optimization process is based on selecting from a multitude of data storage models the one that satisfies the propose problem objective, maximization or minimization of the optimum criterion that is…
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Majorization as a Tool for Optimizing a Class of Matrix Functions.
ERIC Educational Resources Information Center
Kiers, Henk A.
1990-01-01
General algorithms are presented that can be used for optimizing matrix trace functions subject to certain constraints on the parameters. The parameter set that minimizes the majorizing function also decreases the matrix trace function, providing a monotonically convergent algorithm for minimizing the matrix trace function iteratively. (SLD)
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Charge and energy minimization in electrical/magnetic stimulation of nervous tissue
NASA Astrophysics Data System (ADS)
Jezernik, Sašo; Sinkjaer, Thomas; Morari, Manfred
2010-08-01
In this work we address the problem of stimulating nervous tissue with the minimal necessary energy at reduced/minimal charge. Charge minimization is related to a valid safety concern (avoidance and reduction of stimulation-induced tissue and electrode damage). Energy minimization plays a role in battery-driven electrical or magnetic stimulation systems (increased lifetime, repetition rates, reduction of power requirements, thermal management). Extensive new theoretical results are derived by employing an optimal control theory framework. These results include derivation of the optimal electrical stimulation waveform for a mixed energy/charge minimization problem, derivation of the charge-balanced energy-minimal electrical stimulation waveform, solutions of a pure charge minimization problem with and without a constraint on the stimulation amplitude, and derivation of the energy-minimal magnetic stimulation waveform. Depending on the set stimulus pulse duration, energy and charge reductions of up to 80% are deemed possible. Results are verified in simulations with an active, mammalian-like nerve fiber model.
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Charge and energy minimization in electrical/magnetic stimulation of nervous tissue.
Jezernik, Saso; Sinkjaer, Thomas; Morari, Manfred
2010-08-01
In this work we address the problem of stimulating nervous tissue with the minimal necessary energy at reduced/minimal charge. Charge minimization is related to a valid safety concern (avoidance and reduction of stimulation-induced tissue and electrode damage). Energy minimization plays a role in battery-driven electrical or magnetic stimulation systems (increased lifetime, repetition rates, reduction of power requirements, thermal management). Extensive new theoretical results are derived by employing an optimal control theory framework. These results include derivation of the optimal electrical stimulation waveform for a mixed energy/charge minimization problem, derivation of the charge-balanced energy-minimal electrical stimulation waveform, solutions of a pure charge minimization problem with and without a constraint on the stimulation amplitude, and derivation of the energy-minimal magnetic stimulation waveform. Depending on the set stimulus pulse duration, energy and charge reductions of up to 80% are deemed possible. Results are verified in simulations with an active, mammalian-like nerve fiber model.
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Geometric versus numerical optimal control of a dissipative spin-(1/2) particle
DOE Office of Scientific and Technical Information (OSTI.GOV)
Lapert, M.; Sugny, D.; Zhang, Y.
2010-12-15
We analyze the saturation of a nuclear magnetic resonance (NMR) signal using optimal magnetic fields. We consider both the problems of minimizing the duration of the control and its energy for a fixed duration. We solve the optimal control problems by using geometric methods and a purely numerical approach, the grape algorithm, the two methods being based on the application of the Pontryagin maximum principle. A very good agreement is obtained between the two results. The optimal solutions for the energy-minimization problem are finally implemented experimentally with available NMR techniques.
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Layout optimization of DRAM cells using rigorous simulation model for NTD
NASA Astrophysics Data System (ADS)
Jeon, Jinhyuck; Kim, Shinyoung; Park, Chanha; Yang, Hyunjo; Yim, Donggyu; Kuechler, Bernd; Zimmermann, Rainer; Muelders, Thomas; Klostermann, Ulrich; Schmoeller, Thomas; Do, Mun-hoe; Choi, Jung-Hoe
2014-03-01
DRAM chip space is mainly determined by the size of the memory cell array patterns which consist of periodic memory cell features and edges of the periodic array. Resolution Enhancement Techniques (RET) are used to optimize the periodic pattern process performance. Computational Lithography such as source mask optimization (SMO) to find the optimal off axis illumination and optical proximity correction (OPC) combined with model based SRAF placement are applied to print patterns on target. For 20nm Memory Cell optimization we see challenges that demand additional tool competence for layout optimization. The first challenge is a memory core pattern of brick-wall type with a k1 of 0.28, so it allows only two spectral beams to interfere. We will show how to analytically derive the only valid geometrically limited source. Another consequence of two-beam interference limitation is a "super stable" core pattern, with the advantage of high depth of focus (DoF) but also low sensitivity to proximity corrections or changes of contact aspect ratio. This makes an array edge correction very difficult. The edge can be the most critical pattern since it forms the transition from the very stable regime of periodic patterns to non-periodic periphery, so it combines the most critical pitch and highest susceptibility to defocus. Above challenge makes the layout correction to a complex optimization task demanding a layout optimization that finds a solution with optimal process stability taking into account DoF, exposure dose latitude (EL), mask error enhancement factor (MEEF) and mask manufacturability constraints. This can only be achieved by simultaneously considering all criteria while placing and sizing SRAFs and main mask features. The second challenge is the use of a negative tone development (NTD) type resist, which has a strong resist effect and is difficult to characterize experimentally due to negative resist profile taper angles that perturb CD at bottom characterization by scanning electron microscope (SEM) measurements. High resist impact and difficult model data acquisition demand for a simulation model that hat is capable of extrapolating reliably beyond its calibration dataset. We use rigorous simulation models to provide that predictive performance. We have discussed the need of a rigorous mask optimization process for DRAM contact cell layout yielding mask layouts that are optimal in process performance, mask manufacturability and accuracy. In this paper, we have shown the step by step process from analytical illumination source derivation, a NTD and application tailored model calibration to layout optimization such as OPC and SRAF placement. Finally the work has been verified with simulation and experimental results on wafer.
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Targeting the Hedgehog pathway in cancer: can the spines be smoothened?
Ailles, Laurie; Siu, Lillian L
2011-04-15
Aberrant Hedgehog (Hh) pathway signaling has been suggested to play a role in the development of multiple solid tumors and hematologic malignancies. GDC-0449 is a novel first-in-human, first-in-class smoothened (SMO) inhibitor, which has completed its phase I evaluation and achieved proof of concept in tumors with Hh pathway mutations. ©2011 AACR.
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Hedgehog Signaling Regulates Epithelial-Mesenchymal Transition in Pancreatic Cancer Stem-Like Cells
Wang, Feng; Ma, Ling; Zhang, Zhengkui; Liu, Xiaoran; Gao, Hongqiao; Zhuang, Yan; Yang, Pei; Kornmann, Marko; Tian, Xiaodong; Yang, Yinmo
2016-01-01
Hedgehog (Hh) signaling is crucially involved in tumorigenesis. This study aimed to assess the role of Hh signaling in the regulation of epithelial-mesenchymal transition (EMT), stemness properties and chemoresistance of human pancreatic Panc-1 cancer stem cells (CSCs). Panc-1 cells were transfected with recombinant lentiviral vectors to silence SMO and serum-free floating-culture system was used to isolate Panc-1 tumorspheres. The expression of CSC and EMT markers was detected by flow cytometry, real-time RT-PCR and Western blot analysis. Malignant behaviors of Panc-1 CSC were evaluated by tumorigenicity assays and nude mouse lung metastasis model. We found that tumorspheres derived from pancreatic cancer cell line Panc-1 possessed self-renewal, differentiation and stemness properties. Hh pathway and EMT were active in Panc-1 tumorspheres. Inhibition of Hh signaling by SMO knockdown inhibited self-renewal, EMT, invasion, chemoresistance, pulmonary metastasis, tumorigenesis of pancreatic CSCs. In conclusion, Hh signaling contributes to the maintenance of stem-like properties and chemoresistance of pancreatic CSC and promotes the tumorigenesis and metastasis of pancreatic cancer. Hh pathway is a potential molecular target for the development of therapeutic strategies for pancreatic CSCs. PMID:26918054
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NASA Astrophysics Data System (ADS)
Duan, Jiandong; Fan, Shaogui; Wu, Fengjiang; Sun, Li; Wang, Guanglin
2018-06-01
This paper proposes an instantaneous power control method for high speed permanent magnet synchronous generators (PMSG), to realize the decoupled control of active power and reactive power, through vector control based on a sliding mode observer (SMO), and a phase locked loop (PLL). Consequently, the high speed PMSG has a high internal power factor, to ensure efficient operation. Vector control and accurate estimation of the instantaneous power require an accurate estimate of the rotor position. The SMO is able to estimate the back electromotive force (EMF). The rotor position and speed can be obtained using a combination of the PLL technique and the phase compensation method. This method has the advantages of robust operation, and being resistant to noise when estimating the position of the rotor. Using instantaneous power theory, the relationship between the output active power, reactive power, and stator current of the PMSG is deduced, and the power constraint condition is analysed for operation at the unit internal power factor. Finally, the accuracy of the rotor position detection, the instantaneous power detection, and the control methods are verified using simulations and experiments.
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Li, Xiangfei; Lin, Yuliang
2017-01-01
This paper proposes a new scheme of reconstructing current sensor faults and estimating unknown load disturbance for a permanent magnet synchronous motor (PMSM)-driven system. First, the original PMSM system is transformed into two subsystems; the first subsystem has unknown system load disturbances, which are unrelated to sensor faults, and the second subsystem has sensor faults, but is free from unknown load disturbances. Introducing a new state variable, the augmented subsystem that has sensor faults can be transformed into having actuator faults. Second, two sliding mode observers (SMOs) are designed: the unknown load disturbance is estimated by the first SMO in the subsystem, which has unknown load disturbance, and the sensor faults can be reconstructed using the second SMO in the augmented subsystem, which has sensor faults. The gains of the proposed SMOs and their stability analysis are developed via the solution of linear matrix inequality (LMI). Finally, the effectiveness of the proposed scheme was verified by simulations and experiments. The results demonstrate that the proposed scheme can reconstruct current sensor faults and estimate unknown load disturbance for the PMSM-driven system. PMID:29211017
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The Hedgehog Signal Transduction Network
Robbins, David J.; Fei, Dennis Liang; Riobo, Natalia A.
2013-01-01
Hedgehog (Hh) proteins regulate the development of a wide range of metazoan embryonic and adult structures, and disruption of Hh signaling pathways results in various human diseases. Here, we provide a comprehensive review of the signaling pathways regulated by Hh, consolidating data from a diverse array of organisms in a variety of scientific disciplines. Similar to the elucidation of many other signaling pathways, our knowledge of Hh signaling developed in a sequential manner centered on its earliest discoveries. Thus, our knowledge of Hh signaling has for the most part focused on elucidating the mechanism by which Hh regulates the Gli family of transcription factors, the so-called “canonical” Hh signaling pathway. However, in the past few years, numerous studies have shown that Hh proteins can also signal through Gli-independent mechanisms collectively referred to as “noncanonical” signaling pathways. Noncanonical Hh signaling is itself subdivided into two distinct signaling modules: (i) those not requiring Smoothened (Smo) and (ii) those downstream of Smo that do not require Gli transcription factors. Thus, Hh signaling is now proposed to occur through a variety of distinct context-dependent signaling modules that have the ability to crosstalk with one another to form an interacting, dynamic Hh signaling network. PMID:23074268
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Low Volume Aerobic Training Heightens Muscle Deoxygenation in Early Post-Angina Pectoris Patients.
Takagi, Shun; Murase, Norio; Kime, Ryotaro; Niwayama, Masatsugu; Osada, Takuya; Katsumura, Toshihito
2016-01-01
The aim of this study was to investigate the effect of low volume aerobic exercise training on muscle O2 dynamics during exercise in early post-angina pectoris (AP) patients, as a pilot study. Seven AP patients (age: 72 ± 6 years) participated in aerobic exercise training for 12 weeks. Training consisted of continuous cycling exercise for 30 min at the individual's estimated lactate threshold, and the subjects trained for 15 ± 5 exercise sessions over 12 weeks. Before and after training, the subjects performed ramp cycling exercise until exhaustion. Muscle O2 saturation (SmO2) and relative changes from rest in deoxygenated hemoglobin concentration (∆Deoxy-Hb) and total hemoglobin concentration (∆Total-Hb) were monitored at the vastus lateralis by near infrared spatial resolved spectroscopy during exercise. The SmO2 was significantly lower and ∆Deoxy-Hb was significantly higher after training than before training, while there were no significant changes in ∆Total-Hb. These results indicated that muscle deoxygenation and muscle O2 extraction were potentially heightened by aerobic exercise training in AP patients, even though the exercise training volume was low.
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Hedgehog Signaling Regulates Epithelial-Mesenchymal Transition in Pancreatic Cancer Stem-Like Cells.
Wang, Feng; Ma, Ling; Zhang, Zhengkui; Liu, Xiaoran; Gao, Hongqiao; Zhuang, Yan; Yang, Pei; Kornmann, Marko; Tian, Xiaodong; Yang, Yinmo
2016-01-01
Hedgehog (Hh) signaling is crucially involved in tumorigenesis. This study aimed to assess the role of Hh signaling in the regulation of epithelial-mesenchymal transition (EMT), stemness properties and chemoresistance of human pancreatic Panc-1 cancer stem cells (CSCs). Panc-1 cells were transfected with recombinant lentiviral vectors to silence SMO and serum-free floating-culture system was used to isolate Panc-1 tumorspheres. The expression of CSC and EMT markers was detected by flow cytometry, real-time RT-PCR and Western blot analysis. Malignant behaviors of Panc-1 CSC were evaluated by tumorigenicity assays and nude mouse lung metastasis model. We found that tumorspheres derived from pancreatic cancer cell line Panc-1 possessed self-renewal, differentiation and stemness properties. Hh pathway and EMT were active in Panc-1 tumorspheres. Inhibition of Hh signaling by SMO knockdown inhibited self-renewal, EMT, invasion, chemoresistance, pulmonary metastasis, tumorigenesis of pancreatic CSCs. In conclusion, Hh signaling contributes to the maintenance of stem-like properties and chemoresistance of pancreatic CSC and promotes the tumorigenesis and metastasis of pancreatic cancer. Hh pathway is a potential molecular target for the development of therapeutic strategies for pancreatic CSCs.
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The Dark Matter Crisis: Falsification of the Current Standard Model of Cosmology
NASA Astrophysics Data System (ADS)
Kroupa, P.
2012-06-01
The current standard model of cosmology (SMoC) requires The Dual Dwarf Galaxy Theorem to be true according to which two types of dwarf galaxies must exist: primordial dark-matter (DM) dominated (type A) dwarf galaxies, and tidal-dwarf and ram-pressure-dwarf (type B) galaxies void of DM. Type A dwarfs surround the host approximately spherically, while type B dwarfs are typically correlated in phase-space. Type B dwarfs must exist in any cosmological theory in which galaxies interact. Only one type of dwarf galaxy is observed to exist on the baryonic Tully-Fisher plot and in the radius-mass plane. The Milky Way satellite system forms a vast phase-space-correlated structure that includes globular clusters and stellar and gaseous streams. Other galaxies also have phase-space correlated satellite systems. Therefore, The Dual Dwarf Galaxy Theorem is falsified by observation and dynamically relevant cold or warm DM cannot exist. It is shown that the SMoC is incompatible with a large set of other extragalactic observations. Other theoretical solutions to cosmological observations exist. In particular, alone the empirical mass-discrepancy-acceleration correlation constitutes convincing evidence that galactic-scale dynamics must be Milgromian. Major problems with inflationary big bang cosmologies remain unresolved.
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Panwar, Bharat; Raghava, Gajendra P S
2015-04-01
The RNA-protein interactions play a diverse role in the cells, thus identification of RNA-protein interface is essential for the biologist to understand their function. In the past, several methods have been developed for predicting RNA interacting residues in proteins, but limited efforts have been made for the identification of protein-interacting nucleotides in RNAs. In order to discriminate protein-interacting and non-interacting nucleotides, we used various classifiers (NaiveBayes, NaiveBayesMultinomial, BayesNet, ComplementNaiveBayes, MultilayerPerceptron, J48, SMO, RandomForest, SMO and SVM(light)) for prediction model development using various features and achieved highest 83.92% sensitivity, 84.82 specificity, 84.62% accuracy and 0.62 Matthew's correlation coefficient by SVM(light) based models. We observed that certain tri-nucleotides like ACA, ACC, AGA, CAC, CCA, GAG, UGA, and UUU preferred in protein-interaction. All the models have been developed using a non-redundant dataset and are evaluated using five-fold cross validation technique. A web-server called RNApin has been developed for the scientific community (http://crdd.osdd.net/raghava/rnapin/). Copyright © 2015 Elsevier Inc. All rights reserved.
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NASA Astrophysics Data System (ADS)
Arya, L. D.; Koshti, Atul
2018-05-01
This paper investigates the Distributed Generation (DG) capacity optimization at location based on the incremental voltage sensitivity criteria for sub-transmission network. The Modified Shuffled Frog Leaping optimization Algorithm (MSFLA) has been used to optimize the DG capacity. Induction generator model of DG (wind based generating units) has been considered for study. Standard test system IEEE-30 bus has been considered for the above study. The obtained results are also validated by shuffled frog leaping algorithm and modified version of bare bones particle swarm optimization (BBExp). The performance of MSFLA has been found more efficient than the other two algorithms for real power loss minimization problem.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Gao, Y; Liu, B; Kalra, M
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 seeksmore » 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.« less
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Optimization of Tangential Mass Injection for Minimizing Flow Separation in a Scramjet Inlet
1991-12-01
34 Aerospace EnQineering, Vol. 11. No. 8, August 1991, p.23. 26. Heppenheimer , Thomas A . Lecture notes from Hypersonic Technologies seminar. University...AFIT/GAE/ENY,/9 lD-2 ( /~ AD-A243 868 "DTIC OPTIMIZATION OF TANGENTIAL MASS INJECTION FOR MINIMIZING FLOW SEPARATION IN A SC.R-.MJET INLET THESIS...OF TANGENTIAL MASS INJECTION FOR MINIMIZING FLOW SEPARATION IN A SCRAMJET INLEr THESIS Presented to the Faculty of the School of E.ngineering of the
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Energy minimization in medical image analysis: Methodologies and applications.
Zhao, Feng; Xie, Xianghua
2016-02-01
Energy minimization is of particular interest in medical image analysis. In the past two decades, a variety of optimization schemes have been developed. In this paper, we present a comprehensive survey of the state-of-the-art optimization approaches. These algorithms are mainly classified into two categories: continuous method and discrete method. The former includes Newton-Raphson method, gradient descent method, conjugate gradient method, proximal gradient method, coordinate descent method, and genetic algorithm-based method, while the latter covers graph cuts method, belief propagation method, tree-reweighted message passing method, linear programming method, maximum margin learning method, simulated annealing method, and iterated conditional modes method. We also discuss the minimal surface method, primal-dual method, and the multi-objective optimization method. In addition, we review several comparative studies that evaluate the performance of different minimization techniques in terms of accuracy, efficiency, or complexity. These optimization techniques are widely used in many medical applications, for example, image segmentation, registration, reconstruction, motion tracking, and compressed sensing. We thus give an overview on those applications as well. Copyright © 2015 John Wiley & Sons, Ltd.
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Optimal design of a novel remote center-of-motion mechanism for minimally invasive surgical robot
NASA Astrophysics Data System (ADS)
Sun, Jingyuan; Yan, Zhiyuan; Du, Zhijiang
2017-06-01
Surgical robot with a remote center-of-motion (RCM) plays an important role in minimally invasive surgery (MIS) field. To make the mechanism has high flexibility and meet the demand of movements during processing of operation, an optimized RCM mechanism is proposed in this paper. Then, the kinematic performance and workspace are analyzed. Finally, a new optimization objective function is built by using the condition number index and the workspace index.
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Numerical Optimization Using Computer Experiments
NASA Technical Reports Server (NTRS)
Trosset, Michael W.; Torczon, Virginia
1997-01-01
Engineering design optimization often gives rise to problems in which expensive objective functions are minimized by derivative-free methods. We propose a method for solving such problems that synthesizes ideas from the numerical optimization and computer experiment literatures. Our approach relies on kriging known function values to construct a sequence of surrogate models of the objective function that are used to guide a grid search for a minimizer. Results from numerical experiments on a standard test problem are presented.
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The anatomy of choice: active inference and agency.
Friston, Karl; Schwartenbeck, Philipp; Fitzgerald, Thomas; Moutoussis, Michael; Behrens, Timothy; Dolan, Raymond J
2013-01-01
This paper considers agency in the setting of embodied or active inference. In brief, we associate a sense of agency with prior beliefs about action and ask what sorts of beliefs underlie optimal behavior. In particular, we consider prior beliefs that action minimizes the Kullback-Leibler (KL) divergence between desired states and attainable states in the future. This allows one to formulate bounded rationality as approximate Bayesian inference that optimizes a free energy bound on model evidence. We show that constructs like expected utility, exploration bonuses, softmax choice rules and optimism bias emerge as natural consequences of this formulation. Previous accounts of active inference have focused on predictive coding and Bayesian filtering schemes for minimizing free energy. Here, we consider variational Bayes as an alternative scheme that provides formal constraints on the computational anatomy of inference and action-constraints that are remarkably consistent with neuroanatomy. Furthermore, this scheme contextualizes optimal decision theory and economic (utilitarian) formulations as pure inference problems. For example, expected utility theory emerges as a special case of free energy minimization, where the sensitivity or inverse temperature (of softmax functions and quantal response equilibria) has a unique and Bayes-optimal solution-that minimizes free energy. This sensitivity corresponds to the precision of beliefs about behavior, such that attainable goals are afforded a higher precision or confidence. In turn, this means that optimal behavior entails a representation of confidence about outcomes that are under an agent's control.
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Optimal design of the satellite constellation arrangement reconfiguration process
NASA Astrophysics Data System (ADS)
Fakoor, Mahdi; Bakhtiari, Majid; Soleymani, Mahshid
2016-08-01
In this article, a novel approach is introduced for the satellite constellation reconfiguration based on Lambert's theorem. Some critical problems are raised in reconfiguration phase, such as overall fuel cost minimization, collision avoidance between the satellites on the final orbital pattern, and necessary maneuvers for the satellites in order to be deployed in the desired position on the target constellation. To implement the reconfiguration phase of the satellite constellation arrangement at minimal cost, the hybrid Invasive Weed Optimization/Particle Swarm Optimization (IWO/PSO) algorithm is used to design sub-optimal transfer orbits for the satellites existing in the constellation. Also, the dynamic model of the problem will be modeled in such a way that, optimal assignment of the satellites to the initial and target orbits and optimal orbital transfer are combined in one step. Finally, we claim that our presented idea i.e. coupled non-simultaneous flight of satellites from the initial orbital pattern will lead to minimal cost. The obtained results show that by employing the presented method, the cost of reconfiguration process is reduced obviously.
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Influence maximization in complex networks through optimal percolation
NASA Astrophysics Data System (ADS)
Morone, Flaviano; Makse, Hernan; CUNY Collaboration; CUNY Collaboration
The whole frame of interconnections in complex networks hinges on a specific set of structural nodes, much smaller than the total size, which, if activated, would cause the spread of information to the whole network, or, if immunized, would prevent the diffusion of a large scale epidemic. Localizing this optimal, that is, minimal, set of structural nodes, called influencers, is one of the most important problems in network science. Here we map the problem onto optimal percolation in random networks to identify the minimal set of influencers, which arises by minimizing the energy of a many-body system, where the form of the interactions is fixed by the non-backtracking matrix of the network. Big data analyses reveal that the set of optimal influencers is much smaller than the one predicted by previous heuristic centralities. Remarkably, a large number of previously neglected weakly connected nodes emerges among the optimal influencers. Reference: F. Morone, H. A. Makse, Nature 524,65-68 (2015)
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Maximize, minimize or target - optimization for a fitted response from a designed experiment
Anderson-Cook, Christine Michaela; Cao, Yongtao; Lu, Lu
2016-04-01
One of the common goals of running and analyzing a designed experiment is to find a location in the design space that optimizes the response of interest. Depending on the goal of the experiment, we may seek to maximize or minimize the response, or set the process to hit a particular target value. After the designed experiment, a response model is fitted and the optimal settings of the input factors are obtained based on the estimated response model. Furthermore, the suggested optimal settings of the input factors are then used in the production environment.
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DNASynth: a software application to optimization of artificial gene synthesis
NASA Astrophysics Data System (ADS)
Muczyński, Jan; Nowak, Robert M.
2017-08-01
DNASynth is a client-server software application in which the client runs in a web browser. The aim of this program is to support and optimize process of artificial gene synthesizing using Ligase Chain Reaction. Thanks to LCR it is possible to obtain DNA strand coding defined by user peptide. The DNA sequence is calculated by optimization algorithm that consider optimal codon usage, minimal energy of secondary structures and minimal number of required LCR. Additionally absence of sequences characteristic for defined by user set of restriction enzymes is guaranteed. The presented software was tested on synthetic and real data.
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Optimized suspension culture: the rotating-wall vessel
NASA Technical Reports Server (NTRS)
Hammond, T. G.; Hammond, J. M.
2001-01-01
Suspension culture remains a popular modality, which manipulates mechanical culture conditions to maintain the specialized features of cultured cells. The rotating-wall vessel is a suspension culture vessel optimized to produce laminar flow and minimize the mechanical stresses on cell aggregates in culture. This review summarizes the engineering principles, which allow optimal suspension culture conditions to be established, and the boundary conditions, which limit this process. We suggest that to minimize mechanical damage and optimize differentiation of cultured cells, suspension culture should be performed in a solid-body rotation Couette-flow, zero-headspace culture vessel such as the rotating-wall vessel. This provides fluid dynamic operating principles characterized by 1) solid body rotation about a horizontal axis, characterized by colocalization of cells and aggregates of different sedimentation rates, optimally reduced fluid shear and turbulence, and three-dimensional spatial freedom; and 2) oxygenation by diffusion. Optimization of suspension culture is achieved by applying three tradeoffs. First, terminal velocity should be minimized by choosing microcarrier beads and culture media as close in density as possible. Next, rotation in the rotating-wall vessel induces both Coriolis and centrifugal forces, directly dependent on terminal velocity and minimized as terminal velocity is minimized. Last, mass transport of nutrients to a cell in suspension culture depends on both terminal velocity and diffusion of nutrients. In the transduction of mechanical culture conditions into cellular effects, several lines of evidence support a role for multiple molecular mechanisms. These include effects of shear stress, changes in cell cycle and cell death pathways, and upstream regulation of secondary messengers such as protein kinase C. The discipline of suspension culture needs a systematic analysis of the relationship between mechanical culture conditions and biological effects, emphasizing cellular processes important for the industrial production of biological pharmaceuticals and devices.
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Stress-Constrained Structural Topology Optimization with Design-Dependent Loads
NASA Astrophysics Data System (ADS)
Lee, Edmund
Topology optimization is commonly used to distribute a given amount of material to obtain the stiffest structure, with predefined fixed loads. The present work investigates the result of applying stress constraints to topology optimization, for problems with design-depending loading, such as self-weight and pressure. In order to apply pressure loading, a material boundary identification scheme is proposed, iteratively connecting points of equal density. In previous research, design-dependent loading problems have been limited to compliance minimization. The present study employs a more practical approach by minimizing mass subject to failure constraints, and uses a stress relaxation technique to avoid stress constraint singularities. The results show that these design dependent loading problems may converge to a local minimum when stress constraints are enforced. Comparisons between compliance minimization solutions and stress-constrained solutions are also given. The resulting topologies of these two solutions are usually vastly different, demonstrating the need for stress-constrained topology optimization.
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Replica analysis for the duality of the portfolio optimization problem
NASA Astrophysics Data System (ADS)
Shinzato, Takashi
2016-11-01
In the present paper, the primal-dual problem consisting of the investment risk minimization problem and the expected return maximization problem in the mean-variance model is discussed using replica analysis. As a natural extension of the investment risk minimization problem under only a budget constraint that we analyzed in a previous study, we herein consider a primal-dual problem in which the investment risk minimization problem with budget and expected return constraints is regarded as the primal problem, and the expected return maximization problem with budget and investment risk constraints is regarded as the dual problem. With respect to these optimal problems, we analyze a quenched disordered system involving both of these optimization problems using the approach developed in statistical mechanical informatics and confirm that both optimal portfolios can possess the primal-dual structure. Finally, the results of numerical simulations are shown to validate the effectiveness of the proposed method.
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Replica analysis for the duality of the portfolio optimization problem.
Shinzato, Takashi
2016-11-01
In the present paper, the primal-dual problem consisting of the investment risk minimization problem and the expected return maximization problem in the mean-variance model is discussed using replica analysis. As a natural extension of the investment risk minimization problem under only a budget constraint that we analyzed in a previous study, we herein consider a primal-dual problem in which the investment risk minimization problem with budget and expected return constraints is regarded as the primal problem, and the expected return maximization problem with budget and investment risk constraints is regarded as the dual problem. With respect to these optimal problems, we analyze a quenched disordered system involving both of these optimization problems using the approach developed in statistical mechanical informatics and confirm that both optimal portfolios can possess the primal-dual structure. Finally, the results of numerical simulations are shown to validate the effectiveness of the proposed method.
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Li, Bangde; Hayes, John E.; Ziegler, Gregory R.
2015-01-01
In just-about-right (JAR) scaling and ideal scaling, attribute delta (i.e., “Too Little” or “Too Much”) reflects a subject’s dissatisfaction level for an attribute relative to their hypothetical ideal. Dissatisfaction (attribute delta) is a different construct from consumer acceptability, operationalized as liking. Therefore, we hypothesized minimizing dissatisfaction and maximizing liking would yield different optimal formulations. The objective of this research was to compare product optimization strategies, i.e. maximizing liking vis-à-vis minimizing dissatisfaction. Coffee-flavored dairy beverages (n = 20) were formulated using a fractional mixture design that constrained the proportions of coffee extract, milk, sucrose, and water. Participants (n = 388) were randomly assigned to one of three research conditions, where they evaluated 4 of the 20 samples using an incomplete block design. Samples were rated for overall liking and for intensity of the attributes sweetness, milk flavor, thickness and coffee flavor. Where appropriate, measures of overall product quality (Ideal_Delta and JAR_Delta) were calculated as the sum of the absolute values of the four attribute deltas. Optimal formulations were estimated by: a) maximizing liking; b) minimizing Ideal_Delta; or c) minimizing JAR_Delta. A validation study was conducted to evaluate product optimization models. Participants indicated a preference for a coffee-flavored dairy beverage with more coffee extract and less milk and sucrose in the dissatisfaction model compared to the formula obtained by maximizing liking. That is, when liking was optimized, participants generally liked a weaker, milkier and sweeter coffee-flavored dairy beverage. Predicted liking scores were validated in a subsequent experiment, and the optimal product formulated to maximize liking was significantly preferred to that formulated to minimize dissatisfaction by a paired preference test. These findings are consistent with the view that JAR and ideal scaling methods both suffer from attitudinal biases that are not present when liking is assessed. That is, consumers sincerely believe they want ‘dark, rich, hearty’ coffee when they do not. This paper also demonstrates the utility and efficiency of a lean experimental approach. PMID:26005291
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Thermochemistry and Reactivity of Metals Engaged in Chemiionization
2015-12-03
SUPPLEMENTARY NOTES 14. ABSTRACT The exothermicity of the chemi-ionization reaction Sm + O -> SmO+ + e– has been re evaluated. Guided ion beam tandem mass ...tandem mass spectrometer (GIBMS). Such reactions are of direct interest in understanding the chemistry that might occur when such lanthanides are...complete loss of communication. Scintillation can be caused by natural irregularities in the ionosphere. In critical applications, it may be desirable
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The Race Relations Advisory Group: An Intergroup Intervention.
1985-03-01
Washington, DC 20548 National Institute of Education EOLC/SMO 1200 19th Street, N.W. Washington, DC 20208 National Inntitute of Mental Health Division...of Extramural Research Programs 5600 Fishers Lane Rockville, HD 20852 National Institute of Mental Health Minority Group Mental Health Programs Room 7...organization members, balances membership by nender within race, and reflects a repre- sentative cross-section of hierarchical levels and functional
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Preliminary flora of the Sierra Bacadehuachi, Sonora, Mexico
Thomas R. Van Devender; Ana Lilia Reina-Guerrero; George M. Ferguson; George Yatskievych; Beatriz E. Loyola-Reina; Gertrudis Yanes-Arvayo; Maria de la Paz Montanez-Armenta; John L. Anderson; Stephen F. Hale; Sky Jacobs
2013-01-01
The Sierra Bacadéhuachi in east-central Sonora is the westernmost mountain range in the Sierra Madre Occidental (SMO), located east of Bacadéhuachi, Municipio de Bacadéhuachi, 34 km east of the Chihuahua border, and 165 km south of the Arizona border. The vegetation ranges from lowland foothills thornscrub up through desert grassland to oak woodland and pine-oak forest...
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Polyamine Catabolism Is Enhanced after Traumatic Brain Injury
Zahedi, Kamyar; Huttinger, Francis; Morrison, Ryan; Murray-Stewart, Tracy; Casero, Robert A.
2010-01-01
Abstract Polyamines spermine and spermidine are highly regulated, ubiquitous aliphatic cations that maintain DNA structure and function as immunomodulators and as antioxidants. Polyamine homeostasis is disrupted after brain injuries, with concomitant generation of toxic metabolites that may contribute to secondary injuries. To test the hypothesis of increased brain polyamine catabolism after traumatic brain injury (TBI), we determined changes in catabolic enzymes and polyamine levels in the rat brain after lateral controlled cortical impact TBI. Spermine oxidase (SMO) catalyzes the degradation of spermine to spermidine, generating H2O2 and aminoaldehydes. Spermidine/spermine-N1-acetyltransferase (SSAT) catalyzes acetylation of these polyamines, and both are further oxidized in a reaction that generates putrescine, H2O2, and aminoaldehydes. In a rat cortical impact model of TBI, SSAT mRNA increased subacutely (6–24 h) after TBI in ipsilateral cortex and hippocampus. SMO mRNA levels were elevated late, from 3 to 7 days post-injury. Polyamine catabolism increased as well. Spermine levels were normal at 6 h and decreased slightly at 24 h, but were normal again by 72 h post-injury. Spermidine levels also decreased slightly (6–24 h), then increased by ∼50% at 72 h post-injury. By contrast, normally low putrescine levels increased up to sixfold (6–72 h) after TBI. Moreover, N-acetylspermidine (but not N-acetylspermine) was detectable (24–72 h) near the site of injury, consistent with increased SSAT activity. None of these changes were seen in the contralateral hemisphere. Immunohistochemical confirmation indicated that SSAT and SMO were expressed throughout the brain. SSAT-immunoreactivity (SSAT-ir) increased in both neuronal and nonneuronal (likely glial) populations ipsilateral to injury. Interestingly, bilateral increases in cortical SSAT-ir neurons occurred at 72 h post-injury, whereas hippocampal changes occurred only ipsilaterally. Prolonged increases in brain polyamine catabolism are the likely cause of loss of homeostasis in this pathway. The potential for simple therapeutic interventions (e.g., polyamine supplementation or inhibition of polyamine oxidation) is an exciting implication of these studies. PMID:19968558
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A Role for Smoothened during Murine Lens and Cornea Development
Trogrlic, Lidia; Milevski, Stefan V.; Familari, Mary; Martinez, Gemma; de Iongh, Robb U
2014-01-01
Various studies suggest that Hedgehog (Hh) signalling plays roles in human and zebrafish ocular development. Recent studies (Kerr et al., Invest Ophthalmol Vis Sci. 2012; 53, 3316–30) showed that conditionally activating Hh signals promotes murine lens epithelial cell proliferation and disrupts fibre differentiation. In this study we examined the expression of the Hh pathway and the requirement for the Smoothened gene in murine lens development. Expression of Hh pathway components in developing lens was examined by RT-PCR, immunofluorescence and in situ hybridisation. The requirement of Smo in lens development was determined by conditional loss-of-function mutations, using LeCre and MLR10 Cre transgenic mice. The phenotype of mutant mice was examined by immunofluorescence for various markers of cell cycle, lens and cornea differentiation. Hh pathway components (Ptch1, Smo, Gli2, Gli3) were detected in lens epithelium from E12.5. Gli2 was particularly localised to mitotic nuclei and, at E13.5, Gli3 exhibited a shift from cytosol to nucleus, suggesting distinct roles for these transcription factors. Conditional deletion of Smo, from ∼E12.5 (MLR10 Cre) did not affect ocular development, whereas deletion from ∼E9.5 (LeCre) resulted in lens and corneal defects from E14.5. Mutant lenses were smaller and showed normal expression of p57Kip2, c-Maf, E-cadherin and Pax6, reduced expression of FoxE3 and Ptch1 and decreased nuclear Hes1. There was normal G1-S phase but decreased G2-M phase transition at E16.5 and epithelial cell death from E14.5-E16.5. Mutant corneas were thicker due to aberrant migration of Nrp2+ cells from the extraocular mesenchyme, resulting in delayed corneal endothelial but normal epithelial differentiation. These results indicate the Hh pathway is required during a discrete period (E9.5–E12.5) in lens development to regulate lens epithelial cell proliferation, survival and FoxE3 expression. Defective corneal development occurs secondary to defects in lens and appears to be due to defective migration of peri-ocular Nrp2+ neural crest/mesenchymal cells. PMID:25268479
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Oria, Prisca A; Hiscox, Alexandra; Alaii, Jane; Ayugi, Margaret; Mukabana, Wolfgang Richard; Takken, Willem; Leeuwis, Cees
2014-11-18
There has been increasing effort in recent years to incorporate user needs in technology design and re-design. This project employed a bottom-up approach that engaged end users from the outset. Bottom-up approaches have the potential to bolster novel interventions and move them towards adaptive and evidence-based strategies. The present study concerns an innovative use of solar-powered mosquito trapping systems (SMoTS) to control malaria in western Kenya. Our paper highlights the co-dependence of research associated with the development of the SMoTS technology on one hand and research for enhancing the sustainable uptake of that very same intervention within the community on the other. During the pre-intervention year, we examined the design, re-design and piloting of a novel technology to generate lessons for malaria elimination on Rusinga Island. Initial ideas about many technological necessities were evaluated and re-designed following feedback from various sources, including technical and social research as well as broader interactions with the social environment. We documented the interlocking of the multiple processes and activities that took place through process observation and document reviews. We analysed the data within the conceptual framework of system innovation by identifying mutual shaping between technical and social factors. Our findings illustrate how various project stakeholders including project staff, collaborators, donor, and community members simultaneously pursued interdependent technological transformations and social interests. In the ongoing process, we observed how partial outcomes in the technological domain influenced social events at a later phase and vice versa. Looking at malaria intervention projects employing novel technologies as niches that may evolve towards system innovation, helps to reveal interrelations between the various technical and social aspects. Revealing these interrelations requires a different role for research and different perspective on innovation where innovation is more than the technical aspects. This approach therefore requires that research is designed in a way that enables obtaining feedback from both aspects.
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Roberts, Llion A; Muthalib, Makii; Stanley, Jamie; Lichtwark, Glen; Nosaka, Kazunori; Coombes, Jeff S; Peake, Jonathan M
2015-08-15
Cold water immersion (CWI) and active recovery (ACT) are frequently used as postexercise recovery strategies. However, the physiological effects of CWI and ACT after resistance exercise are not well characterized. We examined the effects of CWI and ACT on cardiac output (Q̇), muscle oxygenation (SmO2), blood volume (tHb), muscle temperature (Tmuscle), and isometric strength after resistance exercise. On separate days, 10 men performed resistance exercise, followed by 10 min CWI at 10°C or 10 min ACT (low-intensity cycling). Q̇ (7.9 ± 2.7 l) and Tmuscle (2.2 ± 0.8°C) increased, whereas SmO2 (-21.5 ± 8.8%) and tHb (-10.1 ± 7.7 μM) decreased after exercise (P < 0.05). During CWI, Q̇ (-1.1 ± 0.7 l) and Tmuscle (-6.6 ± 5.3°C) decreased, while tHb (121 ± 77 μM) increased (P < 0.05). In the hour after CWI, Q̇ and Tmuscle remained low, while tHb also decreased (P < 0.05). By contrast, during ACT, Q̇ (3.9 ± 2.3 l), Tmuscle (2.2 ± 0.5°C), SmO2 (17.1 ± 5.7%), and tHb (91 ± 66 μM) all increased (P < 0.05). In the hour after ACT, Tmuscle, and tHb remained high (P < 0.05). Peak isometric strength during 10-s maximum voluntary contractions (MVCs) did not change significantly after CWI, whereas it decreased after ACT (-30 to -45 Nm; P < 0.05). Muscle deoxygenation time during MVCs increased after ACT (P < 0.05), but not after CWI. Muscle reoxygenation time after MVCs tended to increase after CWI (P = 0.052). These findings suggest first that hemodynamics and muscle temperature after resistance exercise are dependent on ambient temperature and metabolic demands with skeletal muscle, and second, that recovery of strength after resistance exercise is independent of changes in hemodynamics and muscle temperature. Copyright © 2015 the American Physiological Society.
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Optimizing Motion Planning for Hyper Dynamic Manipulator
NASA Astrophysics Data System (ADS)
Aboura, Souhila; Omari, Abdelhafid; Meguenni, Kadda Zemalache
2012-01-01
This paper investigates the optimal motion planning for an hyper dynamic manipulator. As case study, we consider a golf swing robot which is consisting with two actuated joint and a mechanical stoppers. Genetic Algorithm (GA) technique is proposed to solve the optimal golf swing motion which is generated by Fourier series approximation. The objective function for GA approach is to minimizing the intermediate and final state, minimizing the robot's energy consummation and maximizing the robot's speed. Obtained simulation results show the effectiveness of the proposed scheme.
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The Preventive Control of a Dengue Disease Using Pontryagin Minimum Principal
NASA Astrophysics Data System (ADS)
Ratna Sari, Eminugroho; Insani, Nur; Lestari, Dwi
2017-06-01
Behaviour analysis for host-vector model without control of dengue disease is based on the value of basic reproduction number obtained using next generation matrices. Furthermore, the model is further developed involving a preventive control to minimize the contact between host and vector. The purpose is to obtain an optimal preventive strategy with minimal cost. The Pontryagin Minimum Principal is used to find the optimal control analytically. The derived optimality model is then solved numerically to investigate control effort to reduce infected class.
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Finding Minimal Addition Chains with a Particle Swarm Optimization Algorithm
NASA Astrophysics Data System (ADS)
León-Javier, Alejandro; Cruz-Cortés, Nareli; Moreno-Armendáriz, Marco A.; Orantes-Jiménez, Sandra
The addition chains with minimal length are the basic block to the optimal computation of finite field exponentiations. It has very important applications in the areas of error-correcting codes and cryptography. However, obtaining the shortest addition chains for a given exponent is a NP-hard problem. In this work we propose the adaptation of a Particle Swarm Optimization algorithm to deal with this problem. Our proposal is tested on several exponents whose addition chains are considered hard to find. We obtained very promising results.
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2016-02-02
Earths ”, MS&T15-Materials Science and Technology 2015 Conference, Columbus, Ohio, October 4-8, 2015. 3. Dulikrvich, G.S., Reddy, S., Orlande, H.R.B...Schwartz, J.and Koch, C.C., “Multi-Objective Design and Optimization of Hard Magnetic Alloys Free of Rare Earths ”, MS&T15-Materials Science and Technology...AFRL-AFOSR-VA-TR-2016-0091 (BRI) Direct and Inverse Design Optimization of Magnetic Alloys with Minimized Use of Rare Earth Elements George
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NASA Technical Reports Server (NTRS)
Macready, William; Wolpert, David
2005-01-01
We demonstrate a new framework for analyzing and controlling distributed systems, by solving constrained optimization problems with an algorithm based on that framework. The framework is ar. information-theoretic extension of conventional full-rationality game theory to allow bounded rational agents. The associated optimization algorithm is a game in which agents control the variables of the optimization problem. They do this by jointly minimizing a Lagrangian of (the probability distribution of) their joint state. The updating of the Lagrange parameters in that Lagrangian is a form of automated annealing, one that focuses the multi-agent system on the optimal pure strategy. We present computer experiments for the k-sat constraint satisfaction problem and for unconstrained minimization of NK functions.
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NASA Technical Reports Server (NTRS)
Moerder, Daniel D.
2014-01-01
MADS (Minimization Assistant for Dynamical Systems) is a trajectory optimization code in which a user-specified performance measure is directly minimized, subject to constraints placed on a low-order discretization of user-supplied plant ordinary differential equations. This document describes the mathematical formulation of the set of trajectory optimization problems for which MADS is suitable, and describes the user interface. Usage examples are provided.
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Harmonic Optimization in Voltage Source Inverter for PV Application using Heuristic Algorithms
NASA Astrophysics Data System (ADS)
Kandil, Shaimaa A.; Ali, A. A.; El Samahy, Adel; Wasfi, Sherif M.; Malik, O. P.
2016-12-01
Selective Harmonic Elimination (SHE) technique is the fundamental switching frequency scheme that is used to eliminate specific order harmonics. Its application to minimize low order harmonics in a three level inverter is proposed in this paper. The modulation strategy used here is SHEPWM and the nonlinear equations, that characterize the low order harmonics, are solved using Harmony Search Algorithm (HSA) to obtain the optimal switching angles that minimize the required harmonics and maintain the fundamental at the desired value. Total Harmonic Distortion (THD) of the output voltage is minimized maintaining selected harmonics within allowable limits. A comparison has been drawn between HSA, Genetic Algorithm (GA) and Newton Raphson (NR) technique using MATLAB software to determine the effectiveness of getting optimized switching angles.
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NASA Astrophysics Data System (ADS)
Sidibe, Souleymane
The implementation and monitoring of operational flight plans is a major occupation for a crew of commercial flights. The purpose of this operation is to set the vertical and lateral trajectories followed by airplane during phases of flight: climb, cruise, descent, etc. These trajectories are subjected to conflicting economical constraints: minimization of flight time and minimization of fuel consumed and environmental constraints. In its task of mission planning, the crew is assisted by the Flight Management System (FMS) which is used to construct the path to follow and to predict the behaviour of the aircraft along the flight plan. The FMS considered in our research, particularly includes an optimization model of flight only by calculating the optimal speed profile that minimizes the overall cost of flight synthesized by a criterion of cost index following a steady cruising altitude. However, the model based solely on optimization of the speed profile is not sufficient. It is necessary to expand the current optimization for simultaneous optimization of the speed and altitude in order to determine an optimum cruise altitude that minimizes the overall cost when the path is flown with the optimal speed profile. Then, a new program was developed. The latter is based on the method of dynamic programming invented by Bellman to solve problems of optimal paths. In addition, the improvement passes through research new patterns of trajectories integrating ascendant cruises and using the lateral plane with the effect of the weather: wind and temperature. Finally, for better optimization, the program takes into account constraint of flight domain of aircrafts which utilize the FMS.
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Risk modelling in portfolio optimization
NASA Astrophysics Data System (ADS)
Lam, W. H.; Jaaman, Saiful Hafizah Hj.; Isa, Zaidi
2013-09-01
Risk management is very important in portfolio optimization. The mean-variance model has been used in portfolio optimization to minimize the investment risk. The objective of the mean-variance model is to minimize the portfolio risk and achieve the target rate of return. Variance is used as risk measure in the mean-variance model. The purpose of this study is to compare the portfolio composition as well as performance between the optimal portfolio of mean-variance model and equally weighted portfolio. Equally weighted portfolio means the proportions that are invested in each asset are equal. The results show that the portfolio composition of the mean-variance optimal portfolio and equally weighted portfolio are different. Besides that, the mean-variance optimal portfolio gives better performance because it gives higher performance ratio than the equally weighted portfolio.
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The anatomy of choice: active inference and agency
Friston, Karl; Schwartenbeck, Philipp; FitzGerald, Thomas; Moutoussis, Michael; Behrens, Timothy; Dolan, Raymond J.
2013-01-01
This paper considers agency in the setting of embodied or active inference. In brief, we associate a sense of agency with prior beliefs about action and ask what sorts of beliefs underlie optimal behavior. In particular, we consider prior beliefs that action minimizes the Kullback–Leibler (KL) divergence between desired states and attainable states in the future. This allows one to formulate bounded rationality as approximate Bayesian inference that optimizes a free energy bound on model evidence. We show that constructs like expected utility, exploration bonuses, softmax choice rules and optimism bias emerge as natural consequences of this formulation. Previous accounts of active inference have focused on predictive coding and Bayesian filtering schemes for minimizing free energy. Here, we consider variational Bayes as an alternative scheme that provides formal constraints on the computational anatomy of inference and action—constraints that are remarkably consistent with neuroanatomy. Furthermore, this scheme contextualizes optimal decision theory and economic (utilitarian) formulations as pure inference problems. For example, expected utility theory emerges as a special case of free energy minimization, where the sensitivity or inverse temperature (of softmax functions and quantal response equilibria) has a unique and Bayes-optimal solution—that minimizes free energy. This sensitivity corresponds to the precision of beliefs about behavior, such that attainable goals are afforded a higher precision or confidence. In turn, this means that optimal behavior entails a representation of confidence about outcomes that are under an agent's control. PMID:24093015
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Attitude determination using vector observations: A fast optimal matrix algorithm
NASA Technical Reports Server (NTRS)
Markley, F. Landis
1993-01-01
The attitude matrix minimizing Wahba's loss function is computed directly by a method that is competitive with the fastest known algorithm for finding this optimal estimate. The method also provides an estimate of the attitude error covariance matrix. Analysis of the special case of two vector observations identifies those cases for which the TRIAD or algebraic method minimizes Wahba's loss function.
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Distributed query plan generation using multiobjective genetic algorithm.
Panicker, Shina; Kumar, T V Vijay
2014-01-01
A distributed query processing strategy, which is a key performance determinant in accessing distributed databases, aims to minimize the total query processing cost. One way to achieve this is by generating efficient distributed query plans that involve fewer sites for processing a query. In the case of distributed relational databases, the number of possible query plans increases exponentially with respect to the number of relations accessed by the query and the number of sites where these relations reside. Consequently, computing optimal distributed query plans becomes a complex problem. This distributed query plan generation (DQPG) problem has already been addressed using single objective genetic algorithm, where the objective is to minimize the total query processing cost comprising the local processing cost (LPC) and the site-to-site communication cost (CC). In this paper, this DQPG problem is formulated and solved as a biobjective optimization problem with the two objectives being minimize total LPC and minimize total CC. These objectives are simultaneously optimized using a multiobjective genetic algorithm NSGA-II. Experimental comparison of the proposed NSGA-II based DQPG algorithm with the single objective genetic algorithm shows that the former performs comparatively better and converges quickly towards optimal solutions for an observed crossover and mutation probability.
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Distributed Query Plan Generation Using Multiobjective Genetic Algorithm
Panicker, Shina; Vijay Kumar, T. V.
2014-01-01
A distributed query processing strategy, which is a key performance determinant in accessing distributed databases, aims to minimize the total query processing cost. One way to achieve this is by generating efficient distributed query plans that involve fewer sites for processing a query. In the case of distributed relational databases, the number of possible query plans increases exponentially with respect to the number of relations accessed by the query and the number of sites where these relations reside. Consequently, computing optimal distributed query plans becomes a complex problem. This distributed query plan generation (DQPG) problem has already been addressed using single objective genetic algorithm, where the objective is to minimize the total query processing cost comprising the local processing cost (LPC) and the site-to-site communication cost (CC). In this paper, this DQPG problem is formulated and solved as a biobjective optimization problem with the two objectives being minimize total LPC and minimize total CC. These objectives are simultaneously optimized using a multiobjective genetic algorithm NSGA-II. Experimental comparison of the proposed NSGA-II based DQPG algorithm with the single objective genetic algorithm shows that the former performs comparatively better and converges quickly towards optimal solutions for an observed crossover and mutation probability. PMID:24963513
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Mitigation of epidemics in contact networks through optimal contact adaptation *
Youssef, Mina; Scoglio, Caterina
2013-01-01
This paper presents an optimal control problem formulation to minimize the total number of infection cases during the spread of susceptible-infected-recovered SIR epidemics in contact networks. In the new approach, contact weighted are reduced among nodes and a global minimum contact level is preserved in the network. In addition, the infection cost and the cost associated with the contact reduction are linearly combined in a single objective function. Hence, the optimal control formulation addresses the tradeoff between minimization of total infection cases and minimization of contact weights reduction. Using Pontryagin theorem, the obtained solution is a unique candidate representing the dynamical weighted contact network. To find the near-optimal solution in a decentralized way, we propose two heuristics based on Bang-Bang control function and on a piecewise nonlinear control function, respectively. We perform extensive simulations to evaluate the two heuristics on different networks. Our results show that the piecewise nonlinear control function outperforms the well-known Bang-Bang control function in minimizing both the total number of infection cases and the reduction of contact weights. Finally, our results show awareness of the infection level at which the mitigation strategies are effectively applied to the contact weights. PMID:23906209
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Mitigation of epidemics in contact networks through optimal contact adaptation.
Youssef, Mina; Scoglio, Caterina
2013-08-01
This paper presents an optimal control problem formulation to minimize the total number of infection cases during the spread of susceptible-infected-recovered SIR epidemics in contact networks. In the new approach, contact weighted are reduced among nodes and a global minimum contact level is preserved in the network. In addition, the infection cost and the cost associated with the contact reduction are linearly combined in a single objective function. Hence, the optimal control formulation addresses the tradeoff between minimization of total infection cases and minimization of contact weights reduction. Using Pontryagin theorem, the obtained solution is a unique candidate representing the dynamical weighted contact network. To find the near-optimal solution in a decentralized way, we propose two heuristics based on Bang-Bang control function and on a piecewise nonlinear control function, respectively. We perform extensive simulations to evaluate the two heuristics on different networks. Our results show that the piecewise nonlinear control function outperforms the well-known Bang-Bang control function in minimizing both the total number of infection cases and the reduction of contact weights. Finally, our results show awareness of the infection level at which the mitigation strategies are effectively applied to the contact weights.
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NASA Astrophysics Data System (ADS)
Mansor, Zakwan; Zakaria, Mohd Zakimi; Nor, Azuwir Mohd; Saad, Mohd Sazli; Ahmad, Robiah; Jamaluddin, Hishamuddin
2017-09-01
This paper presents the black-box modelling of palm oil biodiesel engine (POB) using multi-objective optimization differential evolution (MOODE) algorithm. Two objective functions are considered in the algorithm for optimization; minimizing the number of term of a model structure and minimizing the mean square error between actual and predicted outputs. The mathematical model used in this study to represent the POB system is nonlinear auto-regressive moving average with exogenous input (NARMAX) model. Finally, model validity tests are applied in order to validate the possible models that was obtained from MOODE algorithm and lead to select an optimal model.
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Optimal blood glucose level control using dynamic programming based on minimal Bergman model
NASA Astrophysics Data System (ADS)
Rettian Anggita Sari, Maria; Hartono
2018-03-01
The purpose of this article is to simulate the glucose dynamic and the insulin kinetic of diabetic patient. The model used in this research is a non-linear Minimal Bergman model. Optimal control theory is then applied to formulate the problem in order to determine the optimal dose of insulin in the treatment of diabetes mellitus such that the glucose level is in the normal range for some specific time range. The optimization problem is solved using dynamic programming. The result shows that dynamic programming is quite reliable to represent the interaction between glucose and insulin levels in diabetes mellitus patient.
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Wong, Chee-Woon; Chong, Kok-Keong; Tan, Ming-Hui
2015-07-27
This paper presents an approach to optimize the electrical performance of dense-array concentrator photovoltaic system comprised of non-imaging dish concentrator by considering the circumsolar radiation and slope error effects. Based on the simulated flux distribution, a systematic methodology to optimize the layout configuration of solar cells interconnection circuit in dense array concentrator photovoltaic module has been proposed by minimizing the current mismatch caused by non-uniformity of concentrated sunlight. An optimized layout of interconnection solar cells circuit with minimum electrical power loss of 6.5% can be achieved by minimizing the effects of both circumsolar radiation and slope error.
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Optimality problem of network topology in stocks market analysis
NASA Astrophysics Data System (ADS)
Djauhari, Maman Abdurachman; Gan, Siew Lee
2015-02-01
Since its introduction fifteen years ago, minimal spanning tree has become an indispensible tool in econophysics. It is to filter the important economic information contained in a complex system of financial markets' commodities. Here we show that, in general, that tool is not optimal in terms of topological properties. Consequently, the economic interpretation of the filtered information might be misleading. To overcome that non-optimality problem, a set of criteria and a selection procedure of an optimal minimal spanning tree will be developed. By using New York Stock Exchange data, the advantages of the proposed method will be illustrated in terms of the power-law of degree distribution.
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Influence maximization in complex networks through optimal percolation
NASA Astrophysics Data System (ADS)
Morone, Flaviano; Makse, Hernán A.
2015-08-01
The whole frame of interconnections in complex networks hinges on a specific set of structural nodes, much smaller than the total size, which, if activated, would cause the spread of information to the whole network, or, if immunized, would prevent the diffusion of a large scale epidemic. Localizing this optimal, that is, minimal, set of structural nodes, called influencers, is one of the most important problems in network science. Despite the vast use of heuristic strategies to identify influential spreaders, the problem remains unsolved. Here we map the problem onto optimal percolation in random networks to identify the minimal set of influencers, which arises by minimizing the energy of a many-body system, where the form of the interactions is fixed by the non-backtracking matrix of the network. Big data analyses reveal that the set of optimal influencers is much smaller than the one predicted by previous heuristic centralities. Remarkably, a large number of previously neglected weakly connected nodes emerges among the optimal influencers. These are topologically tagged as low-degree nodes surrounded by hierarchical coronas of hubs, and are uncovered only through the optimal collective interplay of all the influencers in the network. The present theoretical framework may hold a larger degree of universality, being applicable to other hard optimization problems exhibiting a continuous transition from a known phase.
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Influence maximization in complex networks through optimal percolation.
Morone, Flaviano; Makse, Hernán A
2015-08-06
The whole frame of interconnections in complex networks hinges on a specific set of structural nodes, much smaller than the total size, which, if activated, would cause the spread of information to the whole network, or, if immunized, would prevent the diffusion of a large scale epidemic. Localizing this optimal, that is, minimal, set of structural nodes, called influencers, is one of the most important problems in network science. Despite the vast use of heuristic strategies to identify influential spreaders, the problem remains unsolved. Here we map the problem onto optimal percolation in random networks to identify the minimal set of influencers, which arises by minimizing the energy of a many-body system, where the form of the interactions is fixed by the non-backtracking matrix of the network. Big data analyses reveal that the set of optimal influencers is much smaller than the one predicted by previous heuristic centralities. Remarkably, a large number of previously neglected weakly connected nodes emerges among the optimal influencers. These are topologically tagged as low-degree nodes surrounded by hierarchical coronas of hubs, and are uncovered only through the optimal collective interplay of all the influencers in the network. The present theoretical framework may hold a larger degree of universality, being applicable to other hard optimization problems exhibiting a continuous transition from a known phase.
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Using a genetic algorithm to optimize a water-monitoring network for accuracy and cost effectiveness
NASA Astrophysics Data System (ADS)
Julich, R. J.
2004-05-01
The purpose of this project is to determine the optimal spatial distribution of water-monitoring wells to maximize important data collection and to minimize the cost of managing the network. We have employed a genetic algorithm (GA) towards this goal. The GA uses a simple fitness measure with two parts: the first part awards a maximal score to those combinations of hydraulic head observations whose net uncertainty is closest to the value representing all observations present, thereby maximizing accuracy; the second part applies a penalty function to minimize the number of observations, thereby minimizing the overall cost of the monitoring network. We used the linear statistical inference equation to calculate standard deviations on predictions from a numerical model generated for the 501-observation Death Valley Regional Flow System as the basis for our uncertainty calculations. We have organized the results to address the following three questions: 1) what is the optimal design strategy for a genetic algorithm to optimize this problem domain; 2) what is the consistency of solutions over several optimization runs; and 3) how do these results compare to what is known about the conceptual hydrogeology? Our results indicate the genetic algorithms are a more efficient and robust method for solving this class of optimization problems than have been traditional optimization approaches.
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Optimal design of solenoid valve to minimize cavitation by numerical analysis
NASA Astrophysics Data System (ADS)
Ko, Seungbin; Jang, Ilhoon; Song, Simon
2012-11-01
Keeping pace with the development of clean energy, hybrid cars and electric vehicles are getting extensive attention recently. In an electronic-control brake system which is essential to those vehicles, a solenoid valve is used to control external hydraulic pressure that boosts up the driver's braking force. However, strong cavitation occurs at the narrow passage between the ball and seat of a solenoid valve due to sudden decrease in pressure, leading to severe damage to the valve. In this study, we investigate the cavitation numerically to discover geometric parameters to affect the cavitation, and an optimal design to minimize the cavitation using optimization technique. As a result, we found four parameters: seat inner radius, seat angle, seat length, and ball radius. Among them, the seat inner radius affects the cavitation most. Also, we found that preventing a sudden reduction in a flow passage is important to reduce cavitation. Finally using an evolutionary algorithm for optimization we minimized cavitation. The optimal design resulted in the maximum vapor volume of fraction of 0.04 while it was 0.7 for reference geometry.
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NASA Technical Reports Server (NTRS)
Soloway, Donald I.; Alberts, Thomas E.
1989-01-01
It is often proposed that the redundancy in choosing a force distribution for multiple arms grasping a single object should be handled by minimizing a quadratic performance index. The performance index may be formulated in terms of joint torques or in terms of the Cartesian space force/torque applied to the body by the grippers. The former seeks to minimize power consumption while the latter minimizes body stresses. Because the cost functions are related to each other by a joint angle dependent transformation on the weight matrix, it might be argued that either method tends to reduce power consumption, but clearly the joint space minimization is optimal. A comparison of these two options is presented with consideration given to computational cost and power consumption. Simulation results using a two arm robot system are presented to show the savings realized by employing the joint space optimization. These savings are offset by additional complexity, computation time and in some cases processor power consumption.
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DQM: Decentralized Quadratically Approximated Alternating Direction Method of Multipliers
NASA Astrophysics Data System (ADS)
Mokhtari, Aryan; Shi, Wei; Ling, Qing; Ribeiro, Alejandro
2016-10-01
This paper considers decentralized consensus optimization problems where nodes of a network have access to different summands of a global objective function. Nodes cooperate to minimize the global objective by exchanging information with neighbors only. A decentralized version of the alternating directions method of multipliers (DADMM) is a common method for solving this category of problems. DADMM exhibits linear convergence rate to the optimal objective but its implementation requires solving a convex optimization problem at each iteration. This can be computationally costly and may result in large overall convergence times. The decentralized quadratically approximated ADMM algorithm (DQM), which minimizes a quadratic approximation of the objective function that DADMM minimizes at each iteration, is proposed here. The consequent reduction in computational time is shown to have minimal effect on convergence properties. Convergence still proceeds at a linear rate with a guaranteed constant that is asymptotically equivalent to the DADMM linear convergence rate constant. Numerical results demonstrate advantages of DQM relative to DADMM and other alternatives in a logistic regression problem.
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Selection of Reserves for Woodland Caribou Using an Optimization Approach
Schneider, Richard R.; Hauer, Grant; Dawe, Kimberly; Adamowicz, Wiktor; Boutin, Stan
2012-01-01
Habitat protection has been identified as an important strategy for the conservation of woodland caribou (Rangifer tarandus). However, because of the economic opportunity costs associated with protection it is unlikely that all caribou ranges can be protected in their entirety. We used an optimization approach to identify reserve designs for caribou in Alberta, Canada, across a range of potential protection targets. Our designs minimized costs as well as three demographic risk factors: current industrial footprint, presence of white-tailed deer (Odocoileus virginianus), and climate change. We found that, using optimization, 60% of current caribou range can be protected (including 17% in existing parks) while maintaining access to over 98% of the value of resources on public lands. The trade-off between minimizing cost and minimizing demographic risk factors was minimal because the spatial distributions of cost and risk were similar. The prospects for protection are much reduced if protection is directed towards the herds that are most at risk of near-term extirpation. PMID:22363702
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Toward a preoperative planning tool for brain tumor resection therapies.
Coffey, Aaron M; Miga, Michael I; Chen, Ishita; Thompson, Reid C
2013-01-01
Neurosurgical procedures involving tumor resection require surgical planning such that the surgical path to the tumor is determined to minimize the impact on healthy tissue and brain function. This work demonstrates a predictive tool to aid neurosurgeons in planning tumor resection therapies by finding an optimal model-selected patient orientation that minimizes lateral brain shift in the field of view. Such orientations may facilitate tumor access and removal, possibly reduce the need for retraction, and could minimize the impact of brain shift on image-guided procedures. In this study, preoperative magnetic resonance images were utilized in conjunction with pre- and post-resection laser range scans of the craniotomy and cortical surface to produce patient-specific finite element models of intraoperative shift for 6 cases. These cases were used to calibrate a model (i.e., provide general rules for the application of patient positioning parameters) as well as determine the current model-based framework predictive capabilities. Finally, an objective function is proposed that minimizes shift subject to patient position parameters. Patient positioning parameters were then optimized and compared to our neurosurgeon as a preliminary study. The proposed model-driven brain shift minimization objective function suggests an overall reduction of brain shift by 23 % over experiential methods. This work recasts surgical simulation from a trial-and-error process to one where options are presented to the surgeon arising from an optimization of surgical goals. To our knowledge, this is the first realization of an evaluative tool for surgical planning that attempts to optimize surgical approach by means of shift minimization in this manner.
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A Method of Trajectory Design for Manned Asteroids Exploration
NASA Astrophysics Data System (ADS)
Gan, Q. B.; Zhang, Y.; Zhu, Z. F.; Han, W. H.; Dong, X.
2014-11-01
A trajectory optimization method of the nuclear propulsion manned asteroids exploration is presented. In the case of launching between 2035 and 2065, based on the Lambert transfer orbit, the phases of departure from and return to the Earth are searched at first. Then the optimal flight trajectory in the feasible regions is selected by pruning the flight sequences. Setting the nuclear propulsion flight plan as propel-coast-propel, and taking the minimal mass of aircraft departure as the index, the nuclear propulsion flight trajectory is separately optimized using a hybrid method. With the initial value of the optimized local parameters of each three phases, the global parameters are jointedly optimized. At last, the minimal departure mass trajectory design result is given.
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Exact solution for the optimal neuronal layout problem.
Chklovskii, Dmitri B
2004-10-01
Evolution perfected brain design by maximizing its functionality while minimizing costs associated with building and maintaining it. Assumption that brain functionality is specified by neuronal connectivity, implemented by costly biological wiring, leads to the following optimal design problem. For a given neuronal connectivity, find a spatial layout of neurons that minimizes the wiring cost. Unfortunately, this problem is difficult to solve because the number of possible layouts is often astronomically large. We argue that the wiring cost may scale as wire length squared, reducing the optimal layout problem to a constrained minimization of a quadratic form. For biologically plausible constraints, this problem has exact analytical solutions, which give reasonable approximations to actual layouts in the brain. These solutions make the inverse problem of inferring neuronal connectivity from neuronal layout more tractable.
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Dervenis, Christos; Xynos, Evaghelos; Sotiropoulos, George; Gouvas, Nikolaos; Boukovinas, Ioannis; Agalianos, Christos; Androulakis, Nikolaos; Athanasiadis, Athanasios; Christodoulou, Christos; Chrysou, Evangelia; Emmanouilidis, Christos; Georgiou, Panagiotis; Karachaliou, Niki; Katopodi, Ourania; Kountourakis, Panteleimon; Kyriazanos, Ioannis; Makatsoris, Thomas; Papakostas, Pavlos; Papamichael, Demetris; Pechlivanides, George; Pentheroudakis, Georgios; Pilpilidis, Ioannis; Sgouros, Joseph; Tekkis, Paris; Triantopoulou, Charina; Tzardi, Maria; Vassiliou, Vassilis; Vini, Louiza; Xynogalos, Spyridon; Ziras, Nikolaos; Souglakos, John
2016-01-01
There is discrepancy and failure to adhere to current international guidelines for the management of metastatic colorectal cancer (CRC) in hospitals in Greece and Cyprus. The aim of the present document is to provide a consensus on the multidisciplinary management of metastastic CRC, considering both special characteristics of our Healthcare System and international guidelines. Following discussion and online communication among the members of an executive team chosen by the Hellenic Society of Medical Oncology (HeSMO), a consensus for metastastic CRC disease was developed. Statements were subjected to the Delphi methodology on two voting rounds by invited multidisciplinary international experts on CRC. Statements reaching level of agreement by ≥80% were considered as having achieved large consensus, whereas statements reaching 60-80% moderate consensus. One hundred and nine statements were developed. Ninety experts voted for those statements. The median rate of abstain per statement was 18.5% (range: 0-54%). In the end of the process, all statements achieved a large consensus. The importance of centralization, care by a multidisciplinary team, adherence to guidelines, and personalization is emphasized. R0 resection is the only intervention that may offer substantial improvement in the oncological outcomes. PMID:27708505
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Guided ion beam and theoretical studies of the bond energy of SmS+
NASA Astrophysics Data System (ADS)
Armentrout, P. B.; Demireva, Maria; Peterson, Kirk A.
2017-12-01
Previous work has shown that atomic samarium cations react with carbonyl sulfide to form SmS+ + CO in an exothermic and barrierless process. To characterize this reaction further, the bond energy of SmS+ is determined in the present study using guided ion beam tandem mass spectrometry. Reactions of SmS+ with Xe, CO, and O2 are examined. Results for collision-induced dissociation processes with all three molecules along with the endothermicity of the SmS+ + CO → Sm+ + COS exchange reaction are combined to yield D0(Sm+-S) = 3.37 ± 0.20 eV. The CO and O2 reactions also yield a SmSO+ product, with measured endothermicities that indicate D0(SSm+-O) = 3.73 ± 0.16 eV and D0(OSm+-S) = 1.38 ± 0.27 eV. The SmS+ bond energy is compared with theoretical values characterized at several levels of theory, including CCSD(T) complete basis set extrapolations using all-electron basis sets. Multireference configuration interaction calculations with explicit spin-orbit calculations along with composite thermochemistry using the Feller-Peterson-Dixon method and all-electron basis sets were also explored for SmS+, and for comparison, SmO, SmO+, and EuO.
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Guided ion beam and theoretical studies of the bond energy of SmS.
Armentrout, P B; Demireva, Maria; Peterson, Kirk A
2017-12-07
Previous work has shown that atomic samarium cations react with carbonyl sulfide to form SmS + + CO in an exothermic and barrierless process. To characterize this reaction further, the bond energy of SmS + is determined in the present study using guided ion beam tandem mass spectrometry. Reactions of SmS + with Xe, CO, and O 2 are examined. Results for collision-induced dissociation processes with all three molecules along with the endothermicity of the SmS + + CO → Sm + + COS exchange reaction are combined to yield D 0 (Sm + -S) = 3.37 ± 0.20 eV. The CO and O 2 reactions also yield a SmSO + product, with measured endothermicities that indicate D 0 (SSm + -O) = 3.73 ± 0.16 eV and D 0 (OSm + -S) = 1.38 ± 0.27 eV. The SmS + bond energy is compared with theoretical values characterized at several levels of theory, including CCSD(T) complete basis set extrapolations using all-electron basis sets. Multireference configuration interaction calculations with explicit spin-orbit calculations along with composite thermochemistry using the Feller-Peterson-Dixon method and all-electron basis sets were also explored for SmS + , and for comparison, SmO, SmO + , and EuO.
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Enhanced kinetics of polysulfide redox reactions on Mo2C/CNT in lithium-sulfur batteries.
Razaq, Rameez; Sun, Dan; Xin, Ying; Li, Qian; Huang, Taizhong; Zheng, Lei; Zhang, Zhaoliang; Huang, Yunhui
2018-07-20
Among different energy storage devices, the lithium-sulfur (Li-S) battery is the subject of recent attention. However, the capacity decay caused by polysulfide shuttle leading to sluggish kinetics of polysulfide redox reactions is the main hindrance for its practical application in Li-S batteries. Herein, molybdenum carbide nanoparticles anchored on carbon nanotubes (Mo 2 C/CNT) are reported to serve as an efficient cathode material to enhance the electrochemical kinetics of polysulfide conversion in Li-S batteries. Mo 2 C/CNT shows strong adsorption and activation of polar polysulfides and therefore accelerates the redox kinetics of polysulfides, reduces the energy barrier, effectively mitigates the polarization and polysulfide shuttle, thus improving the electrochemical performance. The S-Mo 2 C/CNT composite with 70 wt% sulfur loading exhibits high specific discharge capacity (1206 mA h g -1 at 0.5 C), excellent high-rate performance, long cycle life (900 cycles), and outstanding Coulombic efficiency (∼100%) at a high rate (2 C) corresponding to a capacity decay of only 0.05%. Remarkably, the S-Mo 2 C/CNT cathode with high areal sulfur loading of 2.5 mg cm -2 exhibits high-rate capacities and stable cycling performance over 100 cycles, offering the potential for use in high energy Li-S batteries.
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Enhanced kinetics of polysulfide redox reactions on Mo2C/CNT in lithium–sulfur batteries
NASA Astrophysics Data System (ADS)
Razaq, Rameez; Sun, Dan; Xin, Ying; Li, Qian; Huang, Taizhong; Zheng, Lei; Zhang, Zhaoliang; Huang, Yunhui
2018-07-01
Among different energy storage devices, the lithium–sulfur (Li–S) battery is the subject of recent attention. However, the capacity decay caused by polysulfide shuttle leading to sluggish kinetics of polysulfide redox reactions is the main hindrance for its practical application in Li–S batteries. Herein, molybdenum carbide nanoparticles anchored on carbon nanotubes (Mo2C/CNT) are reported to serve as an efficient cathode material to enhance the electrochemical kinetics of polysulfide conversion in Li–S batteries. Mo2C/CNT shows strong adsorption and activation of polar polysulfides and therefore accelerates the redox kinetics of polysulfides, reduces the energy barrier, effectively mitigates the polarization and polysulfide shuttle, thus improving the electrochemical performance. The S-Mo2C/CNT composite with 70 wt% sulfur loading exhibits high specific discharge capacity (1206 mA h g‑1 at 0.5 C), excellent high-rate performance, long cycle life (900 cycles), and outstanding Coulombic efficiency (∼100%) at a high rate (2 C) corresponding to a capacity decay of only 0.05%. Remarkably, the S-Mo2C/CNT cathode with high areal sulfur loading of 2.5 mg cm‑2 exhibits high-rate capacities and stable cycling performance over 100 cycles, offering the potential for use in high energy Li–S batteries.
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Electrochemical Evaluation of Stainless Steels in Acidified Sodium Chloride Solutions
NASA Technical Reports Server (NTRS)
Calle, L. M.; MacDowell, L. G.; Vinje, R. D.
2004-01-01
This paper presents the results of an investigation in which several 300-series stainless steels (SS): AISI S30403 SS (UNS S30403), AISI 316L SS (UNS S31603), and AISI 317L SS (LINS S31703), as well as highly-alloyed: SS 254-SMO (UNS S32154), AL-6XN (N08367) and AL29-4C (UNS S44735), were evaluated using DC electrochemical techniques in three different electrolyte solutions. The solutions consisted of neutral 3.55% NaCl, 3.55% NaCl in 0.1N HCl, and 3.55% NaCl in 1.0N HCl. These solutions were chosen to simulate environments that are less, similar, and more aggressive, respectively, than the conditions at the Space Shuttle launch pads. The electrochemical test results were compared to atmospheric exposure data and evaluated for their ability to predict the long-term corrosion performance of the subject alloys. The electrochemical measurements for the six alloys indicated that the higher-alloyed SS 254-SMO, AL29-4C, and AL-6XN exhibited significantly higher resistance to localized corrosion than the 300-series SS. There was a correlation between the corrosion performance of the alloys during a two-year atmospheric exposure and the corrosion rates calculated from electrochemical (polarization resistance) measurements.
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Alvers, Ashley L.; Ryan, Sean; Scherz, Paul J.; Huisken, Jan; Bagnat, Michel
2014-01-01
The formation of a single lumen during tubulogenesis is crucial for the development and function of many organs. Although 3D cell culture models have identified molecular mechanisms controlling lumen formation in vitro, their function during vertebrate organogenesis is poorly understood. Using light sheet microscopy and genetic approaches we have investigated single lumen formation in the zebrafish gut. Here we show that during gut development multiple lumens open and enlarge to generate a distinct intermediate, which consists of two adjacent unfused lumens separated by basolateral contacts. We observed that these lumens arise independently from each other along the length of the gut and do not share a continuous apical surface. Resolution of this intermediate into a single, continuous lumen requires the remodeling of contacts between adjacent lumens and subsequent lumen fusion. We show that lumen resolution, but not lumen opening, is impaired in smoothened (smo) mutants, indicating that fluid-driven lumen enlargement and resolution are two distinct processes. Furthermore, we show that smo mutants exhibit perturbations in the Rab11 trafficking pathway and demonstrate that Rab11-mediated trafficking is necessary for single lumen formation. Thus, lumen resolution is a distinct genetically controlled process crucial for single, continuous lumen formation in the zebrafish gut. PMID:24504339
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Resilience-based optimal design of water distribution network
NASA Astrophysics Data System (ADS)
Suribabu, C. R.
2017-11-01
Optimal design of water distribution network is generally aimed to minimize the capital cost of the investments on tanks, pipes, pumps, and other appurtenances. Minimizing the cost of pipes is usually considered as a prime objective as its proportion in capital cost of the water distribution system project is very high. However, minimizing the capital cost of the pipeline alone may result in economical network configuration, but it may not be a promising solution in terms of resilience point of view. Resilience of the water distribution network has been considered as one of the popular surrogate measures to address ability of network to withstand failure scenarios. To improve the resiliency of the network, the pipe network optimization can be performed with two objectives, namely minimizing the capital cost as first objective and maximizing resilience measure of the configuration as secondary objective. In the present work, these two objectives are combined as single objective and optimization problem is solved by differential evolution technique. The paper illustrates the procedure for normalizing the objective functions having distinct metrics. Two of the existing resilience indices and power efficiency are considered for optimal design of water distribution network. The proposed normalized objective function is found to be efficient under weighted method of handling multi-objective water distribution design problem. The numerical results of the design indicate the importance of sizing pipe telescopically along shortest path of flow to have enhanced resiliency indices.
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2017-01-01
This work focuses on the design of transmitting coils in weakly coupled magnetic induction communication systems. We propose several optimization methods that reduce the active, reactive and apparent power consumption of the coil. These problems are formulated as minimization problems, in which the power consumed by the transmitting coil is minimized, under the constraint of providing a required magnetic field at the receiver location. We develop efficient numeric and analytic methods to solve the resulting problems, which are of high dimension, and in certain cases non-convex. For the objective of minimal reactive power an analytic solution for the optimal current distribution in flat disc transmitting coils is provided. This problem is extended to general three-dimensional coils, for which we develop an expression for the optimal current distribution. Considering the objective of minimal apparent power, a method is developed to reduce the computational complexity of the problem by transforming it to an equivalent problem of lower dimension, allowing a quick and accurate numeric solution. These results are verified experimentally by testing a number of coil geometries. The results obtained allow reduced power consumption and increased performances in magnetic induction communication systems. Specifically, for wideband systems, an optimal design of the transmitter coil reduces the peak instantaneous power provided by the transmitter circuitry, and thus reduces its size, complexity and cost. PMID:28192463
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Portfolio optimization with mean-variance model
NASA Astrophysics Data System (ADS)
Hoe, Lam Weng; Siew, Lam Weng
2016-06-01
Investors wish to achieve the target rate of return at the minimum level of risk in their investment. Portfolio optimization is an investment strategy that can be used to minimize the portfolio risk and can achieve the target rate of return. The mean-variance model has been proposed in portfolio optimization. The mean-variance model is an optimization model that aims to minimize the portfolio risk which is the portfolio variance. The objective of this study is to construct the optimal portfolio using the mean-variance model. The data of this study consists of weekly returns of 20 component stocks of FTSE Bursa Malaysia Kuala Lumpur Composite Index (FBMKLCI). The results of this study show that the portfolio composition of the stocks is different. Moreover, investors can get the return at minimum level of risk with the constructed optimal mean-variance portfolio.
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L^1 -optimality conditions for the circular restricted three-body problem
NASA Astrophysics Data System (ADS)
Chen, Zheng
2016-11-01
In this paper, the L^1 -minimization for the translational motion of a spacecraft in the circular restricted three-body problem (CRTBP) is considered. Necessary conditions are derived by using the Pontryagin Maximum Principle (PMP), revealing the existence of bang-bang and singular controls. Singular extremals are analyzed, recalling the existence of the Fuller phenomenon according to the theories developed in (Marchal in J Optim Theory Appl 11(5):441-486, 1973; Zelikin and Borisov in Theory of Chattering Control with Applications to Astronautics, Robotics, Economics, and Engineering. Birkhäuser, Basal 1994; in J Math Sci 114(3):1227-1344, 2003). The sufficient optimality conditions for the L^1 -minimization problem with fixed endpoints have been developed in (Chen et al. in SIAM J Control Optim 54(3):1245-1265, 2016). In the current paper, we establish second-order conditions for optimal control problems with more general final conditions defined by a smooth submanifold target. In addition, the numerical implementation to check these optimality conditions is given. Finally, approximating the Earth-Moon-Spacecraft system by the CRTBP, an L^1 -minimization trajectory for the translational motion of a spacecraft is computed by combining a shooting method with a continuation method in (Caillau et al. in Celest Mech Dyn Astron 114:137-150, 2012; Caillau and Daoud in SIAM J Control Optim 50(6):3178-3202, 2012). The local optimality of the computed trajectory is asserted thanks to the second-order optimality conditions developed.
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Inertial Sea Wave Energy Converter from Mediterranean Sea to Ocean - Design Optimization
NASA Astrophysics Data System (ADS)
Calleri, Marco
Optimization of the number of gyroscopes and flywheel rotational speed of a Wave Energy Converter able to produce 725 kW as the nominal power, in the chosen installation site, respecting some imposed constraints and some dimensions from the previous design, by minimizing the cost of the device and the bearing power losses, through the minimization of the LCOE of the device.
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NASA Astrophysics Data System (ADS)
Osman, Ayat E.
Energy use in commercial buildings constitutes a major proportion of the energy consumption and anthropogenic emissions in the USA. Cogeneration systems offer an opportunity to meet a building's electrical and thermal demands from a single energy source. To answer the question of what is the most beneficial and cost effective energy source(s) that can be used to meet the energy demands of the building, optimizations techniques have been implemented in some studies to find the optimum energy system based on reducing cost and maximizing revenues. Due to the significant environmental impacts that can result from meeting the energy demands in buildings, building design should incorporate environmental criteria in the decision making criteria. The objective of this research is to develop a framework and model to optimize a building's operation by integrating congregation systems and utility systems in order to meet the electrical, heating, and cooling demand by considering the potential life cycle environmental impact that might result from meeting those demands as well as the economical implications. Two LCA Optimization models have been developed within a framework that uses hourly building energy data, life cycle assessment (LCA), and mixed-integer linear programming (MILP). The objective functions that are used in the formulation of the problems include: (1) Minimizing life cycle primary energy consumption, (2) Minimizing global warming potential, (3) Minimizing tropospheric ozone precursor potential, (4) Minimizing acidification potential, (5) Minimizing NOx, SO 2 and CO2, and (6) Minimizing life cycle costs, considering a study period of ten years and the lifetime of equipment. The two LCA optimization models can be used for: (a) long term planning and operational analysis in buildings by analyzing the hourly energy use of a building during a day and (b) design and quick analysis of building operation based on periodic analysis of energy use of a building in a year. A Pareto-optimal frontier is also derived, which defines the minimum cost required to achieve any level of environmental emission or primary energy usage value or inversely the minimum environmental indicator and primary energy usage value that can be achieved and the cost required to achieve that value.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Hintermueller, M., E-mail: hint@math.hu-berlin.de; Kao, C.-Y., E-mail: Ckao@claremontmckenna.edu; Laurain, A., E-mail: laurain@math.hu-berlin.de
2012-02-15
This paper focuses on the study of a linear eigenvalue problem with indefinite weight and Robin type boundary conditions. We investigate the minimization of the positive principal eigenvalue under the constraint that the absolute value of the weight is bounded and the total weight is a fixed negative constant. Biologically, this minimization problem is motivated by the question of determining the optimal spatial arrangement of favorable and unfavorable regions for a species to survive. For rectangular domains with Neumann boundary condition, it is known that there exists a threshold value such that if the total weight is below this thresholdmore » value then the optimal favorable region is like a section of a disk at one of the four corners; otherwise, the optimal favorable region is a strip attached to the shorter side of the rectangle. Here, we investigate the same problem with mixed Robin-Neumann type boundary conditions and study how this boundary condition affects the optimal spatial arrangement.« less
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Globally optimal superconducting magnets part I: minimum stored energy (MSE) current density map.
Tieng, Quang M; Vegh, Viktor; Brereton, Ian M
2009-01-01
An optimal current density map is crucial in magnet design to provide the initial values within search spaces in an optimization process for determining the final coil arrangement of the magnet. A strategy for obtaining globally optimal current density maps for the purpose of designing magnets with coaxial cylindrical coils in which the stored energy is minimized within a constrained domain is outlined. The current density maps obtained utilising the proposed method suggests that peak current densities occur around the perimeter of the magnet domain, where the adjacent peaks have alternating current directions for the most compact designs. As the dimensions of the domain are increased, the current density maps yield traditional magnet designs of positive current alone. These unique current density maps are obtained by minimizing the stored magnetic energy cost function and therefore suggest magnet coil designs of minimal system energy. Current density maps are provided for a number of different domain arrangements to illustrate the flexibility of the method and the quality of the achievable designs.
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Multi-Constraint Multi-Variable Optimization of Source-Driven Nuclear Systems
NASA Astrophysics Data System (ADS)
Watkins, Edward Francis
1995-01-01
A novel approach to the search for optimal designs of source-driven nuclear systems is investigated. Such systems include radiation shields, fusion reactor blankets and various neutron spectrum-shaping assemblies. The novel approach involves the replacement of the steepest-descents optimization algorithm incorporated in the code SWAN by a significantly more general and efficient sequential quadratic programming optimization algorithm provided by the code NPSOL. The resulting SWAN/NPSOL code system can be applied to more general, multi-variable, multi-constraint shield optimization problems. The constraints it accounts for may include simple bounds on variables, linear constraints, and smooth nonlinear constraints. It may also be applied to unconstrained, bound-constrained and linearly constrained optimization. The shield optimization capabilities of the SWAN/NPSOL code system is tested and verified in a variety of optimization problems: dose minimization at constant cost, cost minimization at constant dose, and multiple-nonlinear constraint optimization. The replacement of the optimization part of SWAN with NPSOL is found feasible and leads to a very substantial improvement in the complexity of optimization problems which can be efficiently handled.
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Hu, Yu-Chuan; Li, Gang; Yang, Yang; Han, Yu; Sun, Ying-Zhi; Liu, Zhi-Cheng; Tian, Qiang; Han, Zi-Yang; Liu, Le-De; Hu, Bin-Quan; Qiu, Zi-Yu; Wang, Wen; Cui, Guang-Bin
2017-01-01
Current machine learning techniques provide the opportunity to develop noninvasive and automated glioma grading tools, by utilizing quantitative parameters derived from multi-modal magnetic resonance imaging (MRI) data. However, the efficacies of different machine learning methods in glioma grading have not been investigated.A comprehensive comparison of varied machine learning methods in differentiating low-grade gliomas (LGGs) and high-grade gliomas (HGGs) as well as WHO grade II, III and IV gliomas based on multi-parametric MRI images was proposed in the current study. The parametric histogram and image texture attributes of 120 glioma patients were extracted from the perfusion, diffusion and permeability parametric maps of preoperative MRI. Then, 25 commonly used machine learning classifiers combined with 8 independent attribute selection methods were applied and evaluated using leave-one-out cross validation (LOOCV) strategy. Besides, the influences of parameter selection on the classifying performances were investigated. We found that support vector machine (SVM) exhibited superior performance to other classifiers. By combining all tumor attributes with synthetic minority over-sampling technique (SMOTE), the highest classifying accuracy of 0.945 or 0.961 for LGG and HGG or grade II, III and IV gliomas was achieved. Application of Recursive Feature Elimination (RFE) attribute selection strategy further improved the classifying accuracies. Besides, the performances of LibSVM, SMO, IBk classifiers were influenced by some key parameters such as kernel type, c, gama, K, etc. SVM is a promising tool in developing automated preoperative glioma grading system, especially when being combined with RFE strategy. Model parameters should be considered in glioma grading model optimization. PMID:28599282
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Zhang, Xin; Yan, Lin-Feng; Hu, Yu-Chuan; Li, Gang; Yang, Yang; Han, Yu; Sun, Ying-Zhi; Liu, Zhi-Cheng; Tian, Qiang; Han, Zi-Yang; Liu, Le-De; Hu, Bin-Quan; Qiu, Zi-Yu; Wang, Wen; Cui, Guang-Bin
2017-07-18
Current machine learning techniques provide the opportunity to develop noninvasive and automated glioma grading tools, by utilizing quantitative parameters derived from multi-modal magnetic resonance imaging (MRI) data. However, the efficacies of different machine learning methods in glioma grading have not been investigated.A comprehensive comparison of varied machine learning methods in differentiating low-grade gliomas (LGGs) and high-grade gliomas (HGGs) as well as WHO grade II, III and IV gliomas based on multi-parametric MRI images was proposed in the current study. The parametric histogram and image texture attributes of 120 glioma patients were extracted from the perfusion, diffusion and permeability parametric maps of preoperative MRI. Then, 25 commonly used machine learning classifiers combined with 8 independent attribute selection methods were applied and evaluated using leave-one-out cross validation (LOOCV) strategy. Besides, the influences of parameter selection on the classifying performances were investigated. We found that support vector machine (SVM) exhibited superior performance to other classifiers. By combining all tumor attributes with synthetic minority over-sampling technique (SMOTE), the highest classifying accuracy of 0.945 or 0.961 for LGG and HGG or grade II, III and IV gliomas was achieved. Application of Recursive Feature Elimination (RFE) attribute selection strategy further improved the classifying accuracies. Besides, the performances of LibSVM, SMO, IBk classifiers were influenced by some key parameters such as kernel type, c, gama, K, etc. SVM is a promising tool in developing automated preoperative glioma grading system, especially when being combined with RFE strategy. Model parameters should be considered in glioma grading model optimization.
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Properties of the optimal trajectories for coplanar, aeroassisted orbital transfer
NASA Technical Reports Server (NTRS)
Miele, A.; Wang, T.; Deaton, A. W.
1990-01-01
The optimization of trajectories for coplaner, aeroassisted orbital transfer (AOT) from a high Earth orbit (HEO) to a low Earth orbit (LEO) is examined. In particular, HEO can be a geosynchronous Earth orbit (GEO). It is assumed that the initial and final orbits are circular, that the gravitational field is central and is governed by the inverse square law, and that two impulses are employed, one at HEO exit and one at LEO entry. During the atmospheric pass, the trajectory is controlled via the lift coefficient in such a way that the total characteristic velocity is minimized. First, an ideal optimal trajectory is determined analytically for lift coefficient unbounded. This trajectory is called grazing trajectory, because the atmospheric pass is made by flying at constant altitude along the edge of the atmosphere until the excess velocity is depleted. For the grazing trajectory, the lift coefficient varies in such a way that the lift, the centrifugal force due to the Earth's curvature, the weight, and the Coriolis force due to the Earth's rotation are in static balance. Also, the grazing trajectory minimizes the total characteristic velocity and simultaneously nearly minimizes the peak values of the altitude drop, dynamic pressure, and heating rate. Next, starting from the grazing trajectory results, a real optimal trajectory is determined numerically for the lift coefficient bounded from both below and above. This trajectory is characterized by atmospheric penetration with the smallest possible entry angle, followed by flight at the lift coefficient lower bound. Consistently with the grazing trajectory behavior, the real optimal trajectory minimizes the total characteristic velocity and simultaneously nearly minimizes the peak values of the altitude drop, the dynamic pressure, and the heating rate.
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A duality framework for stochastic optimal control of complex systems
Malikopoulos, Andreas A.
2016-01-01
In this study, we address the problem of minimizing the long-run expected average cost of a complex system consisting of interactive subsystems. We formulate a multiobjective optimization problem of the one-stage expected costs of the subsystems and provide a duality framework to prove that the control policy yielding the Pareto optimal solution minimizes the average cost criterion of the system. We provide the conditions of existence and a geometric interpretation of the solution. For practical situations having constraints consistent with those studied here, our results imply that the Pareto control policy may be of value when we seek to derivemore » online the optimal control policy in complex systems.« less
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Self-Averaging Property of Minimal Investment Risk of Mean-Variance Model.
Shinzato, Takashi
2015-01-01
In portfolio optimization problems, the minimum expected investment risk is not always smaller than the expected minimal investment risk. That is, using a well-known approach from operations research, it is possible to derive a strategy that minimizes the expected investment risk, but this strategy does not always result in the best rate of return on assets. Prior to making investment decisions, it is important to an investor to know the potential minimal investment risk (or the expected minimal investment risk) and to determine the strategy that will maximize the return on assets. We use the self-averaging property to analyze the potential minimal investment risk and the concentrated investment level for the strategy that gives the best rate of return. We compare the results from our method with the results obtained by the operations research approach and with those obtained by a numerical simulation using the optimal portfolio. The results of our method and the numerical simulation are in agreement, but they differ from that of the operations research approach.
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Texture mapping via optimal mass transport.
Dominitz, Ayelet; Tannenbaum, Allen
2010-01-01
In this paper, we present a novel method for texture mapping of closed surfaces. Our method is based on the technique of optimal mass transport (also known as the "earth-mover's metric"). This is a classical problem that concerns determining the optimal way, in the sense of minimal transportation cost, of moving a pile of soil from one site to another. In our context, the resulting mapping is area preserving and minimizes angle distortion in the optimal mass sense. Indeed, we first begin with an angle-preserving mapping (which may greatly distort area) and then correct it using the mass transport procedure derived via a certain gradient flow. In order to obtain fast convergence to the optimal mapping, we incorporate a multiresolution scheme into our flow. We also use ideas from discrete exterior calculus in our computations.
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Nallasivam, Ulaganathan; Shah, Vishesh H.; Shenvi, Anirudh A.; ...
2016-02-10
We present a general Global Minimization Algorithm (GMA) to identify basic or thermally coupled distillation configurations that require the least vapor duty under minimum reflux conditions for separating any ideal or near-ideal multicomponent mixture into a desired number of product streams. In this algorithm, global optimality is guaranteed by modeling the system using Underwood equations and reformulating the resulting constraints to bilinear inequalities. The speed of convergence to the globally optimal solution is increased by using appropriate feasibility and optimality based variable-range reduction techniques and by developing valid inequalities. As a result, the GMA can be coupled with already developedmore » techniques that enumerate basic and thermally coupled distillation configurations, to provide for the first time, a global optimization based rank-list of distillation configurations.« less
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NASA Astrophysics Data System (ADS)
Landsman, Zinoviy
2008-10-01
We present an explicit closed form solution of the problem of minimizing the root of a quadratic functional subject to a system of affine constraints. The result generalizes Z. Landsman, Minimization of the root of a quadratic functional under an affine equality constraint, J. Comput. Appl. Math. 2007, to appear, see
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Polyamine Analogues as Novel Anti-HER Family Agents in Human Breast Cancer
2007-09-01
Davidson NE, & Casero RA Jr. Spermine oxidase SMO(PAOh1), not N1-acetylpolyamine oxidase PAO, is the primary source of cytotoxic H2O2 in polyamine...Distribution Unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT Elevated levels of all three naturally occurring polyamines, spermine , spermidine and...protein in multiple human breast cancer cell lines. This suppression is both time and dose dependent. A relationship between oligoamine structure , growth
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Thomas R. Van Devender; Erik F. Enderson; Dale S. Turner; Roberto A. Villa; Stephen F. Hale; George M. Ferguson; Charles Hedgcock
2013-01-01
Amphibians and reptiles were observed in the Sierra La Madera (59 species), an isolated Sky Island mountain range, and the Sierra Bacadéhuachi (30 species), the westernmost mountain range in the Sierra Madre Occidental (SMO) range in east-central Sonora. These preliminary herpetofaunas were compared with the herpetofauna of the Yécora area in eastern Sonora in the main...
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Propeller noise minimization without thrust loss due to asymmetric blade distribution
NASA Astrophysics Data System (ADS)
Dobrzynski, Werner
1990-11-01
Measures which can be taken to minimize propeller noise caused by asymmetric blade distribution, without loss of thrust, are discussed. The theoretical optimization of angular separation and its relation to the minimization of noise is reviewed. Experimental results on various propellers are discussed.
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Optimal design criteria - prediction vs. parameter estimation
NASA Astrophysics Data System (ADS)
Waldl, Helmut
2014-05-01
G-optimality is a popular design criterion for optimal prediction, it tries to minimize the kriging variance over the whole design region. A G-optimal design minimizes the maximum variance of all predicted values. If we use kriging methods for prediction it is self-evident to use the kriging variance as a measure of uncertainty for the estimates. Though the computation of the kriging variance and even more the computation of the empirical kriging variance is computationally very costly and finding the maximum kriging variance in high-dimensional regions can be time demanding such that we cannot really find the G-optimal design with nowadays available computer equipment in practice. We cannot always avoid this problem by using space-filling designs because small designs that minimize the empirical kriging variance are often non-space-filling. D-optimality is the design criterion related to parameter estimation. A D-optimal design maximizes the determinant of the information matrix of the estimates. D-optimality in terms of trend parameter estimation and D-optimality in terms of covariance parameter estimation yield basically different designs. The Pareto frontier of these two competing determinant criteria corresponds with designs that perform well under both criteria. Under certain conditions searching the G-optimal design on the above Pareto frontier yields almost as good results as searching the G-optimal design in the whole design region. In doing so the maximum of the empirical kriging variance has to be computed only a few times though. The method is demonstrated by means of a computer simulation experiment based on data provided by the Belgian institute Management Unit of the North Sea Mathematical Models (MUMM) that describe the evolution of inorganic and organic carbon and nutrients, phytoplankton, bacteria and zooplankton in the Southern Bight of the North Sea.
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Adopting epidemic model to optimize medication and surgical intervention of excess weight
NASA Astrophysics Data System (ADS)
Sun, Ruoyan
2017-01-01
We combined an epidemic model with an objective function to minimize the weighted sum of people with excess weight and the cost of a medication and surgical intervention in the population. The epidemic model is consisted of ordinary differential equations to describe three subpopulation groups based on weight. We introduced an intervention using medication and surgery to deal with excess weight. An objective function is constructed taking into consideration the cost of the intervention as well as the weight distribution of the population. Using empirical data, we show that fixed participation rate reduces the size of obese population but increases the size for overweight. An optimal participation rate exists and decreases with respect to time. Both theoretical analysis and empirical example confirm the existence of an optimal participation rate, u*. Under u*, the weighted sum of overweight (S) and obese (O) population as well as the cost of the program is minimized. This article highlights the existence of an optimal participation rate that minimizes the number of people with excess weight and the cost of the intervention. The time-varying optimal participation rate could contribute to designing future public health interventions of excess weight.
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Hybrid optimal online-overnight charging coordination of plug-in electric vehicles in smart grid
NASA Astrophysics Data System (ADS)
Masoum, Mohammad A. S.; Nabavi, Seyed M. H.
2016-10-01
Optimal coordinated charging of plugged-in electric vehicles (PEVs) in smart grid (SG) can be beneficial for both consumers and utilities. This paper proposes a hybrid optimal online followed by overnight charging coordination of high and low priority PEVs using discrete particle swarm optimization (DPSO) that considers the benefits of both consumers and electric utilities. Objective functions are online minimization of total cost (associated with grid losses and energy generation) and overnight valley filling through minimization of the total load levels. The constraints include substation transformer loading, node voltage regulations and the requested final battery state of charge levels (SOCreq). The main challenge is optimal selection of the overnight starting time (toptimal-overnight,start) to guarantee charging of all vehicle batteries to the SOCreq levels before the requested plug-out times (treq) which is done by simultaneously solving the online and overnight objective functions. The online-overnight PEV coordination approach is implemented on a 449-node SG; results are compared for uncoordinated and coordinated battery charging as well as a modified strategy using cost minimizations for both online and overnight coordination. The impact of toptimal-overnight,start on performance of the proposed PEV coordination is investigated.
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An efficient algorithm for automatic phase correction of NMR spectra based on entropy minimization
NASA Astrophysics Data System (ADS)
Chen, Li; Weng, Zhiqiang; Goh, LaiYoong; Garland, Marc
2002-09-01
A new algorithm for automatic phase correction of NMR spectra based on entropy minimization is proposed. The optimal zero-order and first-order phase corrections for a NMR spectrum are determined by minimizing entropy. The objective function is constructed using a Shannon-type information entropy measure. Entropy is defined as the normalized derivative of the NMR spectral data. The algorithm has been successfully applied to experimental 1H NMR spectra. The results of automatic phase correction are found to be comparable to, or perhaps better than, manual phase correction. The advantages of this automatic phase correction algorithm include its simple mathematical basis and the straightforward, reproducible, and efficient optimization procedure. The algorithm is implemented in the Matlab program ACME—Automated phase Correction based on Minimization of Entropy.
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Real-Time Adaptive Least-Squares Drag Minimization for Performance Adaptive Aeroelastic Wing
NASA Technical Reports Server (NTRS)
Ferrier, Yvonne L.; Nguyen, Nhan T.; Ting, Eric
2016-01-01
This paper contains a simulation study of a real-time adaptive least-squares drag minimization algorithm for an aeroelastic model of a flexible wing aircraft. The aircraft model is based on the NASA Generic Transport Model (GTM). The wing structures incorporate a novel aerodynamic control surface known as the Variable Camber Continuous Trailing Edge Flap (VCCTEF). The drag minimization algorithm uses the Newton-Raphson method to find the optimal VCCTEF deflections for minimum drag in the context of an altitude-hold flight control mode at cruise conditions. The aerodynamic coefficient parameters used in this optimization method are identified in real-time using Recursive Least Squares (RLS). The results demonstrate the potential of the VCCTEF to improve aerodynamic efficiency for drag minimization for transport aircraft.
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Geometric modeling of space-optimal unit-cell-based tissue engineering scaffolds
NASA Astrophysics Data System (ADS)
Rajagopalan, Srinivasan; Lu, Lichun; Yaszemski, Michael J.; Robb, Richard A.
2005-04-01
Tissue engineering involves regenerating damaged or malfunctioning organs using cells, biomolecules, and synthetic or natural scaffolds. Based on their intended roles, scaffolds can be injected as space-fillers or be preformed and implanted to provide mechanical support. Preformed scaffolds are biomimetic "trellis-like" structures which, on implantation and integration, act as tissue/organ surrogates. Customized, computer controlled, and reproducible preformed scaffolds can be fabricated using Computer Aided Design (CAD) techniques and rapid prototyping devices. A curved, monolithic construct with minimal surface area constitutes an efficient substrate geometry that promotes cell attachment, migration and proliferation. However, current CAD approaches do not provide such a biomorphic construct. We address this critical issue by presenting one of the very first physical realizations of minimal surfaces towards the construction of efficient unit-cell based tissue engineering scaffolds. Mask programmability, and optimal packing density of triply periodic minimal surfaces are used to construct the optimal pore geometry. Budgeted polygonization, and progressive minimal surface refinement facilitate the machinability of these surfaces. The efficient stress distributions, as deduced from the Finite Element simulations, favor the use of these scaffolds for orthopedic applications.
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Multi-Objective Online Initialization of Spacecraft Formations
NASA Technical Reports Server (NTRS)
Jeffrey, Matthew; Breger, Louis; How, Jonathan P.
2007-01-01
This paper extends a previously developed method for finding spacecraft initial conditions (ICs) that minimize the drift resulting from J2 disturbances while also minimizing the fuel required to attain those ICs. It generalizes the single spacecraft optimization to a formation-wide optimization valid for an arbitrary number of vehicles. Additionally, the desired locations of the spacecraft, separate from the starting location, can be specified, either with respect to a reference orbit, or relative to the other spacecraft in the formation. The three objectives (minimize drift, minimize fuel, and maintain a geometric template) are expressed as competing costs in a linear optimization, and are traded against one another through the use of scalar weights. By carefully selecting these weights and re-initializing the formation at regular intervals, a closed-loop, formation-wide control system is created. This control system can be used to reconfigure the formations on the fly, and creates fuel-efficient plans by placing the spacecraft in semi-invariant orbits. The overall approach is demonstrated through nonlinear simulations for two formations a GEO orbit, and an elliptical orbit.
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Random Matrix Approach for Primal-Dual Portfolio Optimization Problems
NASA Astrophysics Data System (ADS)
Tada, Daichi; Yamamoto, Hisashi; Shinzato, Takashi
2017-12-01
In this paper, we revisit the portfolio optimization problems of the minimization/maximization of investment risk under constraints of budget and investment concentration (primal problem) and the maximization/minimization of investment concentration under constraints of budget and investment risk (dual problem) for the case that the variances of the return rates of the assets are identical. We analyze both optimization problems by the Lagrange multiplier method and the random matrix approach. Thereafter, we compare the results obtained from our proposed approach with the results obtained in previous work. Moreover, we use numerical experiments to validate the results obtained from the replica approach and the random matrix approach as methods for analyzing both the primal and dual portfolio optimization problems.
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Shaver, Aaron C; Greig, Bruce W; Mosse, Claudio A; Seegmiller, Adam C
2015-05-01
Optimizing a clinical flow cytometry panel can be a subjective process dependent on experience. We develop a quantitative method to make this process more rigorous and apply it to B lymphoblastic leukemia/lymphoma (B-ALL) minimal residual disease (MRD) testing. We retrospectively analyzed our existing three-tube, seven-color B-ALL MRD panel and used our novel method to develop an optimized one-tube, eight-color panel, which was tested prospectively. The optimized one-tube, eight-color panel resulted in greater efficiency of time and resources with no loss in diagnostic power. Constructing a flow cytometry panel using a rigorous, objective, quantitative method permits optimization and avoids problems of interdependence and redundancy in a large, multiantigen panel. Copyright© by the American Society for Clinical Pathology.
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Satellite Constellation Optimization for Turkish Armed Forces
2013-03-01
capability. 29 III. OPTIMIZATION WITH STK A. ANALYSIS The goal was to minimize the number of satellites and then minimize the number of planes...www.oosa.unvienna.org/pdf/reports/ac105/AC105_1005E.pdf. Wertz, James R. and Larson, Wiley J. “Space Mission Analysis and Design (Third Edition).” Space...Systems Tool Kit software for simulation and analysis of several possible communications and remote sensing satellite constellations covering Turkish
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Optimization of Highway Work Zone Decisions Considering Short-Term and Long-Term Impacts
2010-01-01
strategies which can minimize the one-time work zone cost. Considering the complex and combinatorial nature of this optimization problem, a heuristic...combination of lane closure and traffic control strategies which can minimize the one-time work zone cost. Considering the complex and combinatorial nature ...zone) NV # the number of vehicle classes NPV $ Net Present Value p’(t) % Adjusted traffic diversion rate at time t p(t) % Natural diversion rate
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Patel, Sita Sharan; Mahindroo, Neeraj; Udayabanu, Malairaman
2016-10-01
The present study was aimed to evaluate the effect of Urtica dioica (UD) extract against chronic unpredictable stress (CUS)-induced associative memory dysfunction and attempted to explore the possible mechanism. Male Swiss albino mice (25-30g) were divided into six groups, viz. group-I received 0.3% carboxymethyl cellulose and served as control (CTRL), group II was exposed to CUS (21days) and received vehicle (CUS), group III was subjected to CUS and received Hypericum perforatum extract (350mg/kg, p.o.) (CUS+HYP), group IV received Hypericum perforatum extract (350mg/kg, p.o.) (CTRL+HYP); group V was subjected to CUS and received UD extract (50mg/kg, p.o.) (CUS+UD), group VI received UD extract (50mg/kg, p.o.) (CTRL+UD). CUS significantly induced body weight loss (p<0.05) and associative memory impairment in step down task (p<0.05) as compared to control mice. CUS significantly downregulated Smo (p<0.05), Gli1 (p<0.01), cyclin D1 (p<0.05), BDNF (p<0.01), TrKB (p<0.01) and MAPK1 (p<0.01) mRNA expression in hippocampus as compared to control mice. CUS significantly increased the levels of TBARS (p<0.01) and nitric oxide (p<0.001), and decreased catalase (p<0.001) and total thiol (p<0.01) in plasma resulting in oxidative stress and inflammation. Chronic UD administration significantly reverted CUS mediated body weight loss (p<0.05) and cognitive impairment (p<0.05). UD administration significantly decreased the levels of TBARS (p<0.01) and nitric oxide (p<0.05), and increased the levels of catalase (p<0.01) and total thiol (p<0.05) in plasma. Chronic UD administration significantly upregulated hippocampal Smo (p<0.05), Gli1 (p<0.001), cyclin D1 (p<0.05), BDNF (p<0.05), TrKB (p<0.05) and MAPK1 (p<0.05) in stressed mice. Further, UD extract did not reverse cyclopamine induced downregulation of Gli1 and Ptch1 mRNA in hippocampal slices. UD modulated Smo-Gli1 pathway in the hippocampus as well as exerted anti-inflammatory and antioxidant effects. UD extract might prove to be effective for stress mediated neurological disorders. Copyright © 2016 Elsevier Masson SAS. All rights reserved.
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Optimal Design of Functionally Graded Metallic Foam Insulations
NASA Technical Reports Server (NTRS)
Haftka, Raphael T.; Sankar, Bhavani; Venkataraman, Satchi; Zhu, Huadong
2002-01-01
The focus of our work has been on developing an insight into the physics that govern the optimum design of thermal insulation for use in thermal protection systems of launch vehicle. Of particular interest was to obtain optimality criteria for designing foam insulations that have density (or porosity) distributions through the thickness for optimum thermal performance. We investigate the optimum design of functionally graded thermal insulation for steady state heat transfer through the foam. We showed that the heat transfer in the foam has competing modes, of radiation and conduction. The problem assumed a fixed inside temperature of 400 K and varied the aerodynamic surface heating on the outside surface from 0.2 to 1.0 MW/sq m. The thermal insulation develops a high temperature gradient through the thickness. Investigation of the model developed for heat conduction in foams showed that at high temperatures (as on outside wall) intracellular radiation dominates the heat transfer in the foam. Minimizing radiation requires reducing the pore size, which increases the density of the foam. At low temperatures (as on the inside wall), intracellular conduction (of the metal and air) dominates the heat transfer. Minimizing conduction requires increasing the pore size. This indicated that for every temperature there was an optimum value of density that minimized the heat transfer coefficient. Two optimization studies were performed. One was to minimize the heat transmitted though a fixed thickness insulation by varying density profiles. The second was to obtain the minimum mass insulation for specified thickness. Analytical optimality criteria were derived for the cases considered. The optimality condition for minimum heat transfer required that at each temperature we find the density that minimizes the heat transfer coefficient. Once a relationship between the optimum heat transfer coefficient and the temperature was found, the design problem reduced to the solution of a simple nonlinear differential equation. Preliminary results of this work were presented at the American Society of Composites meeting, and the final version was submitted for publication in the AIAA Journal. In addition to minimizing the transmitted heat, we investigated the optimum design for minimum weight given an acceptable level of heat transmission through the insulation. The optimality criterion developed was different from that obtained for minimizing beat transfer coefficient. For minimum mass design, we had to find for a given temperature the optimum density, which minimized the logarithmic derivative of the insulation thermal conductivity with respect to its density. The logarithmic derivative is defined as the ratio of relative change in the dependent response (thermal conductivity) to the relative change in the independent variable (density). The results have been documented as a conference paper that will be presented at the upcoming AIAA.
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Optimally Stopped Optimization
NASA Astrophysics Data System (ADS)
Vinci, Walter; Lidar, Daniel
We combine the fields of heuristic optimization and optimal stopping. We propose a strategy for benchmarking randomized optimization algorithms that minimizes the expected total cost for obtaining a good solution with an optimal number of calls to the solver. To do so, rather than letting the objective function alone define a cost to be minimized, we introduce a further cost-per-call of the algorithm. We show that this problem can be formulated using optimal stopping theory. The expected cost is a flexible figure of merit for benchmarking probabilistic solvers that can be computed when the optimal solution is not known, and that avoids the biases and arbitrariness that affect other measures. The optimal stopping formulation of benchmarking directly leads to a real-time, optimal-utilization strategy for probabilistic optimizers with practical impact. We apply our formulation to benchmark the performance of a D-Wave 2X quantum annealer and the HFS solver, a specialized classical heuristic algorithm designed for low tree-width graphs. On a set of frustrated-loop instances with planted solutions defined on up to N = 1098 variables, the D-Wave device is between one to two orders of magnitude faster than the HFS solver.
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On the Convergence Analysis of the Optimized Gradient Method.
Kim, Donghwan; Fessler, Jeffrey A
2017-01-01
This paper considers the problem of unconstrained minimization of smooth convex functions having Lipschitz continuous gradients with known Lipschitz constant. We recently proposed the optimized gradient method for this problem and showed that it has a worst-case convergence bound for the cost function decrease that is twice as small as that of Nesterov's fast gradient method, yet has a similarly efficient practical implementation. Drori showed recently that the optimized gradient method has optimal complexity for the cost function decrease over the general class of first-order methods. This optimality makes it important to study fully the convergence properties of the optimized gradient method. The previous worst-case convergence bound for the optimized gradient method was derived for only the last iterate of a secondary sequence. This paper provides an analytic convergence bound for the primary sequence generated by the optimized gradient method. We then discuss additional convergence properties of the optimized gradient method, including the interesting fact that the optimized gradient method has two types of worstcase functions: a piecewise affine-quadratic function and a quadratic function. These results help complete the theory of an optimal first-order method for smooth convex minimization.
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On the Convergence Analysis of the Optimized Gradient Method
Kim, Donghwan; Fessler, Jeffrey A.
2016-01-01
This paper considers the problem of unconstrained minimization of smooth convex functions having Lipschitz continuous gradients with known Lipschitz constant. We recently proposed the optimized gradient method for this problem and showed that it has a worst-case convergence bound for the cost function decrease that is twice as small as that of Nesterov’s fast gradient method, yet has a similarly efficient practical implementation. Drori showed recently that the optimized gradient method has optimal complexity for the cost function decrease over the general class of first-order methods. This optimality makes it important to study fully the convergence properties of the optimized gradient method. The previous worst-case convergence bound for the optimized gradient method was derived for only the last iterate of a secondary sequence. This paper provides an analytic convergence bound for the primary sequence generated by the optimized gradient method. We then discuss additional convergence properties of the optimized gradient method, including the interesting fact that the optimized gradient method has two types of worstcase functions: a piecewise affine-quadratic function and a quadratic function. These results help complete the theory of an optimal first-order method for smooth convex minimization. PMID:28461707
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Solar electricity supply isolines of generation capacity and storage.
Grossmann, Wolf; Grossmann, Iris; Steininger, Karl W
2015-03-24
The recent sharp drop in the cost of photovoltaic (PV) electricity generation accompanied by globally rapidly increasing investment in PV plants calls for new planning and management tools for large-scale distributed solar networks. Of major importance are methods to overcome intermittency of solar electricity, i.e., to provide dispatchable electricity at minimal costs. We find that pairs of electricity generation capacity G and storage S that give dispatchable electricity and are minimal with respect to S for a given G exhibit a smooth relationship of mutual substitutability between G and S. These isolines between G and S support the solving of several tasks, including the optimal sizing of generation capacity and storage, optimal siting of solar parks, optimal connections of solar parks across time zones for minimizing intermittency, and management of storage in situations of far below average insolation to provide dispatchable electricity. G-S isolines allow determining the cost-optimal pair (G,S) as a function of the cost ratio of G and S. G-S isolines provide a method for evaluating the effect of geographic spread and time zone coverage on costs of solar electricity.
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Recombinant host cells and media for ethanol production
Wood, Brent E; Ingram, Lonnie O; Yomano, Lorraine P; York, Sean W
2014-02-18
Disclosed are recombinant host cells suitable for degrading an oligosaccharide that have been optimized for growth and production of high yields of ethanol, and methods of making and using these cells. The invention further provides minimal media comprising urea-like compounds for economical production of ethanol by recombinant microorganisms. Recombinant host cells in accordance with the invention are modified by gene mutation to eliminate genes responsible for the production of unwanted products other than ethanol, thereby increasing the yield of ethanol produced from the oligosaccharides, relative to unmutated parent strains. The new and improved strains of recombinant bacteria are capable of superior ethanol productivity and yield when grown under conditions suitable for fermentation in minimal growth media containing inexpensive reagents. Systems optimized for ethanol production combine a selected optimized minimal medium with a recombinant host cell optimized for use in the selected medium. Preferred systems are suitable for efficient ethanol production by simultaneous saccharification and fermentation (SSF) using lignocellulose as an oligosaccharide source. The invention also provides novel isolated polynucleotide sequences, polypeptide sequences, vectors and antibodies.
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Solar electricity supply isolines of generation capacity and storage
Grossmann, Wolf; Grossmann, Iris; Steininger, Karl W.
2015-01-01
The recent sharp drop in the cost of photovoltaic (PV) electricity generation accompanied by globally rapidly increasing investment in PV plants calls for new planning and management tools for large-scale distributed solar networks. Of major importance are methods to overcome intermittency of solar electricity, i.e., to provide dispatchable electricity at minimal costs. We find that pairs of electricity generation capacity G and storage S that give dispatchable electricity and are minimal with respect to S for a given G exhibit a smooth relationship of mutual substitutability between G and S. These isolines between G and S support the solving of several tasks, including the optimal sizing of generation capacity and storage, optimal siting of solar parks, optimal connections of solar parks across time zones for minimizing intermittency, and management of storage in situations of far below average insolation to provide dispatchable electricity. G−S isolines allow determining the cost-optimal pair (G,S) as a function of the cost ratio of G and S. G−S isolines provide a method for evaluating the effect of geographic spread and time zone coverage on costs of solar electricity. PMID:25755261
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John D. Palting
2013-01-01
The Sierra de Bacadéhuachi is a poorly sampled extension of the Sierra Madre Occidental (SMO) located in east-central Sonora near the town of Bacadéhuachi. Sampling of moths using mercury vapor and ultraviolet lights occurred in summer and fall 2011, and spring 2012 at Rincón de Guadalupe, located in pine-oak forest at 1680 m elevation. Approximately 400 taxa of moths...
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Peripheral Nerve Repair and Prevention of Neuroma Formation
2014-09-01
Magee1), ADRB3, β arrestin, Patched 1 (Ptch1) and 2, desert hedgehog (Dhh), smoothen (Smo), Src kinase, and UCP1. (Months 6-36) c. We will also use the...antibody. Figure 9. Representative photomicrographs of desert hedgehog staining in perineurial fibroblasts. A.) C57/BL6 mouse nerve was isolated 3...days after BMP2 induction stained with desert hedgehog (red) and NF (green). P. perineurium; E. endoneurium. Note that the mouse nerve, unlike the
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Sperm whale assessment in the Western Ionian Sea using acoustic data from deep sea observatories
NASA Astrophysics Data System (ADS)
Caruso, Francesco; Bellia, Giorgio; Beranzoli, Laura; De Domenico, Emilio; Larosa, Giuseppina; Marinaro, Giuditta; Papale, Elena; Pavan, Gianni; Pellegrino, Carmelo; Pulvirenti, Sara; Riccobene, Giorgio; Scandura, Danila; Sciacca, Virginia; Viola, Salvatore
2015-04-01
The Italian National Institute of Nuclear Physics (INFN) operates two deep sea infrastructures: Capo Passero, Western Ionian Sea 3,600 meters of depth, and Catania Wester Ionian Sea 2,100 m depth. At the two sites, several research observatories have been run: OnDE, NEMO-SN1, SMO, KM3NeT-Italia most of them jointly operated between INFN and INGV. In all these observatories, passive acoustic sensors (hydrophones) have been installed. Passive Acoustics Monitoring (PAM) is nowadays the main tool of the bioacoustics to study marine mammals. In particular, receiving the sounds emitted by cetaceans from a multi-hydrophones array installed in a cabled seafloor observatory, a research about the ecological dynamics of the species may be performed. Data acquired with the hydrophones installed aboard the OnDE, SMO and KM3NeT-Italia observatories will be reported. Thanks to acquired data, the acoustic presence of the sperm whales was assessed and studied for several years (2005:2013). An "ad hoc" algorithm was also developed to allow the automatic identification of the "clicks" emitted by the sperm whales and measure the size of detected animals. According to the results obtained, the sperm whale population in the area is well-distributed in size, sex and sexual maturity. Although specimens more than 14 meters of length (old males) seem to be absent.
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Irvine, David A.; Zhang, Bin; Kinstrie, Ross; Tarafdar, Anuradha; Morrison, Heather; Campbell, Victoria L.; Moka, Hothri A.; Ho, Yinwei; Nixon, Colin; Manley, Paul W.; Wheadon, Helen; Goodlad, John R.; Holyoake, Tessa L.; Bhatia, Ravi; Copland, Mhairi
2016-01-01
Targeting the Hedgehog (Hh) pathway represents a potential leukaemia stem cell (LSC)-directed therapy which may compliment tyrosine kinase inhibitors (TKIs) to eradicate LSC in chronic phase (CP) chronic myeloid leukaemia (CML). We set out to elucidate the role of Hh signaling in CP-CML and determine if inhibition of Hh signaling, through inhibition of smoothened (SMO), was an effective strategy to target CP-CML LSC. Assessment of Hh pathway gene and protein expression demonstrated that the Hh pathway is activated in CD34+ CP-CML stem/progenitor cells. LDE225 (Sonidegib), a small molecule, clinically investigated SMO inhibitor, used alone and in combination with nilotinib, inhibited the Hh pathway in CD34+ CP-CML cells, reducing the number and self-renewal capacity of CML LSC in vitro. The combination had no effect on normal haemopoietic stem cells. When combined, LDE225 + nilotinib reduced CD34+ CP-CML cell engraftment in NSG mice and, upon administration to EGFP+ /SCLtTA/TRE-BCR-ABL mice, the combination enhanced survival with reduced leukaemia development in secondary transplant recipients. In conclusion, the Hh pathway is deregulated in CML stem and progenitor cells. We identify Hh pathway inhibition, in combination with nilotinib, as a potentially effective therapeutic strategy to improve responses in CP-CML by targeting both stem and progenitor cells. PMID:27157927
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Maldonado-Sánchez, Denisse; Gutiérrez-Rodríguez, Carla; Ornelas, Juan Francisco
2016-06-01
By integrating mitochondrial DNA (mtDNA), microsatellites and ecological niche modelling (ENM), we investigated the phylogeography of Mexican populations of the common bush-tanager Chlorospingus ophthalmicus to examine the relative role of geographical and ecological features, as well as Pleistocene climatic oscillations in driving the diversification. We sequenced mtDNA of individuals collected throughout the species range in Mexico and genotyped them at seven microsatellite loci. Phylogeographic, population genetics and coalescent methods were used to assess patterns of genetic structure, gene flow and demographic history. ENM was used to infer contractions and expansions at different time periods as well as differences in climatic conditions among lineages. The retrieved mitochondrial and microsatellite groups correspond with the fragmented cloud forest distribution in mountain ranges and morphotectonic provinces. Differing climatic conditions between mountain ranges were detected, and palaeodistribution modelling as well as demographic history analyses, indicated recent population expansions throughout the Sierra Madre Oriental (SMO). The marked genetic structure of C. ophthalmicus was promoted by the presence of ecological and geographical barriers that restricted the movement of individuals among mountain ranges. The SMO was mainly affected by Pleistocene climatic oscillations, with the moist forests model best fitting the displayed genetic patterns of populations in this mountain range. Copyright © 2016 Elsevier Inc. All rights reserved.
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Spontaneous magnetic order in complex materials: Role of longitudinal spin-orbit interactions
NASA Astrophysics Data System (ADS)
Chakraborty, Subrata; Vijay, Amrendra
2017-06-01
We show that the longitudinal spin-orbit interactions (SOI) critically determine the fate of spontaneous magnetic order (SMO) in complex materials. To study the magnetic response of interacting electrons constituting the material, we implement an extension of the Hubbard model that faithfully accounts for the SOI. Next, we use the double-time Green functions of quantum statistical mechanics to obtain the spontaneous magnetization, Msp , and thence ascertain the possibility of SMO. For materials with quenched SOI, in an arbitrary dimension, Msp vanishes at finite temperatures, implying the presence of the disordered (paramagnetic) phase. This is consistent with and goes beyond the Bogolyubov's inequality based analysis in one and two dimensions. In the presence of longitudinal SOI, Msp , for materials in an arbitrary dimension, remains non-zero at finite temperatures, which indicates the existence of the ordered (ferromagnetic) phase. As a plausible experimental evidence of the present SOI-based phenomenology, we discuss, inter alia, a recent experimental study on Y4Mn1-xGa12-yGey, an intermetallic compound, which exhibits a magnetic phase transition (paramagnetic to ferromagnetic) upon tuning the fraction of Ge atoms and thence the vacancies of the magnetic centers in this system. The availability of Ge atoms to form a direct chemical bond with octahedral Mn in this material appears to quench the SOI and, as a consequence, favours the formation of the disordered (paramagnetic) phase.
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Katic, Jelena; Loers, Gabriele; Tosic, Jelena; Schachner, Melitta; Kleene, Ralf
2017-08-01
The immunoglobulin superfamily adhesion molecule close homolog of L1 (CHL1) plays important roles during nervous system development. Here, we identified the hedgehog receptor patched-1 (PTCH1) as a novel CHL1-binding protein and showed that CHL1 interacts with the first extracellular loop of PTCH1 via its extracellular domain. Colocalization and co-immunoprecipitation of CHL1 with PTCH1 suggest an association of CHL1 with this major component of the hedgehog signaling pathway. The trans -interaction of CHL1 with PTCH1 promotes neuronal survival in cultures of dissociated cerebellar granule cells and of organotypic cerebellar slices. An inhibitor of the PTCH1-regulated hedgehog signal transducer, smoothened (SMO), and inhibitors of RhoA and Rho-associated kinase (ROCK) 1 and 2 prevent CHL1-dependent survival of cultured cerebellar granule cells and survival of cerebellar granule and Purkinje cells in organotypic cultures. In histological sections from 10- and 14-day-old CHL1-deficient mice, enhanced apoptosis of granule, but not Purkinje, cells was observed. The results of the present study indicate that CHL1 triggers PTCH1-, SMO-, RhoA- and ROCK-dependent signal transduction pathways to promote neuronal survival after cessation of the major morphogenetic events during mouse cerebellar development. © 2017. Published by The Company of Biologists Ltd.
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Computational Approaches for Designing Protein/Inhibitor Complexes and Membrane Protein Variants
NASA Astrophysics Data System (ADS)
Vijayendran, Krishna Gajan
Drug discovery of small-molecule protein inhibitors is a vast enterprise that involves several scientific disciplines (i.e. genomics, cell biology, x-ray crystallography, chemistry, computer science, statistics), with each discipline focusing on a particular aspect of the process. In this thesis, I use computational and experimental approaches to explore the most fundamental aspect of drug discovery: the molecular interactions of small-molecules inhibitors with proteins. In Part I (Chapters I and II), I describe how computational docking approaches can be used to identify structurally diverse molecules that can inhibit multiple protein targets in the brain. I illustrate this approach using the examples of microtubule-stabilizing agents and inhibitors of cyclooxygenase(COX)-I and 5-lipoxygenase (5-LOX). In Part II (Chapters III and IV), I focus on membrane proteins, which are notoriously difficult to work with due to their low natural abundances, low yields for heterologous over expression, and propensities toward aggregation. I describe a general approach for designing water-soluble variants of membrane proteins, for the purpose of developing cell-free, label-free, detergent-free, solution-phase studies of protein structure and small-molecule binding. I illustrate this approach through the design of a water-soluble variant of the membrane protein Smoothened, wsSMO. This wsSMO stands to serve as a first-step towards developing membrane protein analogs of this important signaling protein and drug target.
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Zhu, Qingsong; Jin, Lihua; Casero, Robert A.
2013-01-01
Our previous studies demonstrated that specific polyamine analogues, oligoamines, down-regulated the activity of a key polyamine biosynthesis enzyme, ornithine decarboxylase (ODC), and suppressed expression of estrogen receptor alpha (ERα) in human breast cancer cells. However, the mechanism underlying the potential regulation of ERα expression by polyamine metabolism has not been explored. Here, we demonstrated that RNAi-mediated knockdown of ODC (ODC KD) down-regulated the polyamine pool, and hindered growth in ERα-positive MCF7 and T47D and ERα-negative MDA-MB-231 breast cancer cells. ODC KD significantly induced the expression and activity of the key polyamine catabolism enzymes, spermine oxidase (SMO) and spermidine/spermine N1-acetyltransferase (SSAT). However, ODC KD-induced growth inhibition could not be reversed by exogenous spermidine or overexpression of antizyme inhibitor (AZI), suggesting that regulation of ODC on cell proliferation may involve the signaling pathways independent of polyamine metabolism. In MCF7 and T47D cells, ODC KD, but not DFMO treatment, diminished the mRNA and protein expression of ERα. Overexpression of antizyme (AZ), an ODC inhibitory protein, suppressed ERα expression, suggesting that ODC plays an important role in regulation of ERα expression. Decrease of ERα expression by ODC siRNA altered the mRNA expression of a subset of ERα response genes. Our previous analysis showed that oligoamines disrupt the binding of Sp1 family members to an ERα minimal promoter element containing GC/CA-rich boxes. By using DNA affinity precipitation and mass spectrometry analysis, we identified ZBTB7A, MeCP2, PARP-1, AP2, and MAZ as co-factors of Sp1 family members that are associated with the ERα minimal promoter element. Taken together, these data provide insight into a novel antiestrogenic mechanism for polyamine biosynthesis enzymes in breast cancer. PMID:22976807
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In-die mask registration measurement on 28nm-node and beyond
NASA Astrophysics Data System (ADS)
Chen, Shen Hung; Cheng, Yung Feng; Chen, Ming Jui
2013-09-01
As semiconductor go to smaller node, the critical dimension (CD) of process become more and more small. For lithography, RET (Resolution Enhancement Technology) applications can be used for wafer printing of smaller CD/pitch on 28nm node and beyond. SMO (Source Mask Optimization), DPT (Double Patterning Technology) and SADP (Self-Align Double Patterning) can provide lower k1 value for lithography. In another way, image placement error and overlay control also become more and more important for smaller chip size (advanced node). Mask registration (image placement error) and mask overlay are important factors to affect wafer overlay control/performance especially for DPT or SADP. In traditional method, the designed registration marks (cross type, square type) with larger CD were put into scribe-line of mask frame for registration and overlay measurement. However, these patterns are far way from real patterns. It does not show the registration of real pattern directly and is not a convincing method. In this study, the in-die (in-chip) registration measurement is introduced. We extract the dummy patterns that are close to main pattern from post-OPC (Optical Proximity Correction) gds by our desired rule and choose the patterns that distribute over whole mask uniformly. The convergence test shows 100 points measurement has a reliable result.
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Electrical comparison of iN7 EUV hybrid and EUV single patterning BEOL metal layers
NASA Astrophysics Data System (ADS)
Larivière, Stéphane; Wilson, Christopher J.; Kutrzeba Kotowska, Bogumila; Versluijs, Janko; Decoster, Stefan; Mao, Ming; van der Veen, Marleen H.; Jourdan, Nicolas; El-Mekki, Zaid; Heylen, Nancy; Kesters, Els; Verdonck, Patrick; Béral, Christophe; Van den Heuvel, Dieter; De Bisschop, Peter; Bekaert, Joost; Blanco, Victor; Ciofi, Ivan; Wan, Danny; Briggs, Basoene; Mallik, Arindam; Hendrickx, Eric; Kim, Ryoung-han; McIntyre, Greg; Ronse, Kurt; Bömmels, Jürgen; Tőkei, Zsolt; Mocuta, Dan
2018-03-01
The semiconductor scaling roadmap shows the continuous node to node scaling to push Moore's law down to the next generations. In that context, the foundry N5 node requires 32nm metal pitch interconnects for the advanced logic Back- End of Line (BEoL). 193immersion usage now requires self-aligned and/or multiple patterning technique combinations to enable such critical dimension. On the other hand, EUV insertion investigation shows that 32nm metal pitch is still a challenge but, related to process flow complexity, presents some clear motivations. Imec has already evaluated on test chip vehicles with different patterning approaches: 193i SAQP (Self-Aligned Quadruple Patterning), LE3 (triple patterning Litho Etch), tone inversion, EUV SE (Single Exposure) with SMO (Source-mask optimization). Following the run path in the technology development for EUV insertion, imec N7 platform (iN7, corresponding node to the foundry N5) is developed for those BEoL layers. In this paper, following technical motivation and development learning, a comparison between the iArF SAQP/EUV block hybrid integration scheme and a single patterning EUV flow is proposed. These two integration patterning options will be finally compared from current morphological and electrical criteria.
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Zhou, Ya-Qing; Wu, Bao-Shan; Lin, Guan-Hua; Li, Yang; Chen, Di-Chun; Zhang, Peng; Yu, Ming-Yu; Zhang, Bin-Bin; Yun, Da-Qin
2017-10-04
Although some kinds of semiconductor metal oxides (SMOs) have been applied as electron selective layers (ESLs) for planar perovskite solar cells (PSCs), electron transfer is still limited by low electron mobility and defect film formation of SMO ESLs fabricated via low-temperature solution process. Herein, the C 70 interlayer between TiO 2 and (HC(NH 2 ) 2 PbI 3 ) x (CH 3 NH 3 PbCl 3 ) 1-x is prepared by spin-coating and low-temperature annealing for planar n-i-p PSCs. The resultant TiO 2 /C 70 ESL shows good surface morphology, efficient electron extraction, and facilitation of high-quality perovskite film formation, which can be attributed to the suitable nanosize and the superior electronic property of C 70 molecules. In comparison with pristine TiO 2 -based PSCs, the efficiency and hysteresis index are, respectively, enhanced 28% and reduced 76% by adding the C 70 interlayer between TiO 2 and perovskite on the basis of statistical data of more than 50 cells. With the main advantages of low-temperature process and optimized interface, the champion efficiency of PSCs on flexible substrates could exceed 12% in contrast with the above 18% on rigid substrate.
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Self-Averaging Property of Minimal Investment Risk of Mean-Variance Model
Shinzato, Takashi
2015-01-01
In portfolio optimization problems, the minimum expected investment risk is not always smaller than the expected minimal investment risk. That is, using a well-known approach from operations research, it is possible to derive a strategy that minimizes the expected investment risk, but this strategy does not always result in the best rate of return on assets. Prior to making investment decisions, it is important to an investor to know the potential minimal investment risk (or the expected minimal investment risk) and to determine the strategy that will maximize the return on assets. We use the self-averaging property to analyze the potential minimal investment risk and the concentrated investment level for the strategy that gives the best rate of return. We compare the results from our method with the results obtained by the operations research approach and with those obtained by a numerical simulation using the optimal portfolio. The results of our method and the numerical simulation are in agreement, but they differ from that of the operations research approach. PMID:26225761
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Khan, M Nisa
2016-02-10
We expansively investigate thermal behaviors of various general-purpose light-emitting diode (LED) lamps and apply our measured results, validated by simulation, to establish lamp design rules for optimizing their optical and thermal properties. These design rules provide the means to minimize lumen depreciation over time by minimizing the periods for lamps to reach thermal steady-state while maintaining their high luminous efficacy and omnidirectional light distribution capability. While it is well known that minimizing the junction temperature of an LED leads to a longer lifetime and an increased lumen output, our study demonstrates, for the first time, to the best of our knowledge, that it is also important to minimize the time it takes to reach thermal equilibrium because doing so minimizes lumen depreciation and enhances light output and color stability during operation. Specifically, we have found that, in addition to inadequate heat-sink fin areas for a lamp configuration, LEDs mounted on multiple boards, as opposed to a single board, lead to longer periods for reaching thermal equilibrium contributing to larger lumen depreciation.
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Nonexpansiveness of a linearized augmented Lagrangian operator for hierarchical convex optimization
NASA Astrophysics Data System (ADS)
Yamagishi, Masao; Yamada, Isao
2017-04-01
Hierarchical convex optimization concerns two-stage optimization problems: the first stage problem is a convex optimization; the second stage problem is the minimization of a convex function over the solution set of the first stage problem. For the hierarchical convex optimization, the hybrid steepest descent method (HSDM) can be applied, where the solution set of the first stage problem must be expressed as the fixed point set of a certain nonexpansive operator. In this paper, we propose a nonexpansive operator that yields a computationally efficient update when it is plugged into the HSDM. The proposed operator is inspired by the update of the linearized augmented Lagrangian method. It is applicable to characterize the solution set of recent sophisticated convex optimization problems found in the context of inverse problems, where the sum of multiple proximable convex functions involving linear operators must be minimized to incorporate preferable properties into the minimizers. For such a problem formulation, there has not yet been reported any nonexpansive operator that yields an update free from the inversions of linear operators in cases where it is utilized in the HSDM. Unlike previously known nonexpansive operators, the proposed operator yields an inversion-free update in such cases. As an application of the proposed operator plugged into the HSDM, we also present, in the context of the so-called superiorization, an algorithmic solution to a convex optimization problem over the generalized convex feasible set where the intersection of the hard constraints is not necessarily simple.
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A parallel Jacobson-Oksman optimization algorithm. [parallel processing (computers)
NASA Technical Reports Server (NTRS)
Straeter, T. A.; Markos, A. T.
1975-01-01
A gradient-dependent optimization technique which exploits the vector-streaming or parallel-computing capabilities of some modern computers is presented. The algorithm, derived by assuming that the function to be minimized is homogeneous, is a modification of the Jacobson-Oksman serial minimization method. In addition to describing the algorithm, conditions insuring the convergence of the iterates of the algorithm and the results of numerical experiments on a group of sample test functions are presented. The results of these experiments indicate that this algorithm will solve optimization problems in less computing time than conventional serial methods on machines having vector-streaming or parallel-computing capabilities.
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A Numerical Optimization Approach for Tuning Fuzzy Logic Controllers
NASA Technical Reports Server (NTRS)
Woodard, Stanley E.; Garg, Devendra P.
1998-01-01
This paper develops a method to tune fuzzy controllers using numerical optimization. The main attribute of this approach is that it allows fuzzy logic controllers to be tuned to achieve global performance requirements. Furthermore, this approach allows design constraints to be implemented during the tuning process. The method tunes the controller by parameterizing the membership functions for error, change-in-error and control output. The resulting parameters form a design vector which is iteratively changed to minimize an objective function. The minimal objective function results in an optimal performance of the system. A spacecraft mounted science instrument line-of-sight pointing control is used to demonstrate results.
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NASA Astrophysics Data System (ADS)
Safuan, N. S.; Fathullah, M.; Shayfull, Z.; Nasir, S. M.; Hazwan, M. H. M.
2017-09-01
In injection moulding process, it is important to keep the productivity increase constantly with least of waste produced such as warpage defect. Thus, this study is concerning on minimizing warpage defect on wheel caster part. Apart from eliminating product wastes, this project also giving out best optimization techniques using response surface methodology. This research studied on five parameters A-packing pressure, B-packing time, C-mold temperature, D-melting temperature and E-cooling time. The optimization showed that packing pressure is the most significant parameter. Warpage have been improved 42.64% from 0.6524 mm to 0.3742mm.
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Ultra-low-loss tapered optical fibers with minimal lengths
NASA Astrophysics Data System (ADS)
Nagai, Ryutaro; Aoki, Takao
2014-11-01
We design and fabricate ultra-low-loss tapered optical fibers (TOFs) with minimal lengths. We first optimize variations of the torch scan length using the flame-brush method for fabricating TOFs with taper angles that satisfy the adiabaticity criteria. We accordingly fabricate TOFs with optimal shapes and compare their transmission to TOFs with a constant taper angle and TOFs with an exponential shape. The highest transmission measured for TOFs with an optimal shape is in excess of 99.7 % with a total TOF length of only 23 mm, whereas TOFs with a constant taper angle of 2 mrad reach 99.6 % transmission for a 63 mm TOF length.
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NASA Astrophysics Data System (ADS)
Mazoyer, J.; Pueyo, L.; N'Diaye, M.; Fogarty, K.; Zimmerman, N.; Soummer, R.; Shaklan, S.; Norman, C.
2018-01-01
High-contrast imaging and spectroscopy provide unique constraints for exoplanet formation models as well as for planetary atmosphere models. Instrumentation techniques in this field have greatly improved over the last two decades, with the development of stellar coronagraphy, in parallel with specific methods of wavefront sensing and control. Next generation space- and ground-based telescopes will enable the characterization of cold solar-system-like planets for the first time and maybe even in situ detection of bio-markers. However, the growth of primary mirror diameters, necessary for these detections, comes with an increase of their complexity (segmentation, secondary mirror features). These discontinuities in the aperture can greatly limit the performance of coronagraphic instruments. In this context, we introduced a new technique, Active Correction of Aperture Discontinuities-Optimized Stroke Minimization (ACAD-OSM), to correct for the diffractive effects of aperture discontinuities in the final image plane of a coronagraph, using deformable mirrors. In this paper, we present several tools that can be used to optimize the performance of this technique for its application to future large missions. In particular, we analyzed the influence of the deformable setup (size and separating distance) and found that there is an optimal point for this setup, optimizing the performance of the instrument in contrast and throughput while minimizing the strokes applied to the deformable mirrors. These results will help us design future coronagraphic instruments to obtain the best performance.
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Hyperopt: a Python library for model selection and hyperparameter optimization
NASA Astrophysics Data System (ADS)
Bergstra, James; Komer, Brent; Eliasmith, Chris; Yamins, Dan; Cox, David D.
2015-01-01
Sequential model-based optimization (also known as Bayesian optimization) is one of the most efficient methods (per function evaluation) of function minimization. This efficiency makes it appropriate for optimizing the hyperparameters of machine learning algorithms that are slow to train. The Hyperopt library provides algorithms and parallelization infrastructure for performing hyperparameter optimization (model selection) in Python. This paper presents an introductory tutorial on the usage of the Hyperopt library, including the description of search spaces, minimization (in serial and parallel), and the analysis of the results collected in the course of minimization. This paper also gives an overview of Hyperopt-Sklearn, a software project that provides automatic algorithm configuration of the Scikit-learn machine learning library. Following Auto-Weka, we take the view that the choice of classifier and even the choice of preprocessing module can be taken together to represent a single large hyperparameter optimization problem. We use Hyperopt to define a search space that encompasses many standard components (e.g. SVM, RF, KNN, PCA, TFIDF) and common patterns of composing them together. We demonstrate, using search algorithms in Hyperopt and standard benchmarking data sets (MNIST, 20-newsgroups, convex shapes), that searching this space is practical and effective. In particular, we improve on best-known scores for the model space for both MNIST and convex shapes. The paper closes with some discussion of ongoing and future work.
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A comparative study on stress and compliance based structural topology optimization
NASA Astrophysics Data System (ADS)
Hailu Shimels, G.; Dereje Engida, W.; Fakhruldin Mohd, H.
2017-10-01
Most of structural topology optimization problems have been formulated and solved to either minimize compliance or weight of a structure under volume or stress constraints, respectively. Even if, a lot of researches are conducted on these two formulation techniques separately, there is no clear comparative study between the two approaches. This paper intends to compare these formulation techniques, so that an end user or designer can choose the best one based on the problems they have. Benchmark problems under the same boundary and loading conditions are defined, solved and results are compared based on these formulations. Simulation results shows that the two formulation techniques are dependent on the type of loading and boundary conditions defined. Maximum stress induced in the design domain is higher when the design domains are formulated using compliance based formulations. Optimal layouts from compliance minimization formulation has complex layout than stress based ones which may lead the manufacturing of the optimal layouts to be challenging. Optimal layouts from compliance based formulations are dependent on the material to be distributed. On the other hand, optimal layouts from stress based formulation are dependent on the type of material used to define the design domain. High computational time for stress based topology optimization is still a challenge because of the definition of stress constraints at element level. Results also shows that adjustment of convergence criterions can be an alternative solution to minimize the maximum stress developed in optimal layouts. Therefore, a designer or end user should choose a method of formulation based on the design domain defined and boundary conditions considered.
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Switching neuronal state: optimal stimuli revealed using a stochastically-seeded gradient algorithm.
Chang, Joshua; Paydarfar, David
2014-12-01
Inducing a switch in neuronal state using energy optimal stimuli is relevant to a variety of problems in neuroscience. Analytical techniques from optimal control theory can identify such stimuli; however, solutions to the optimization problem using indirect variational approaches can be elusive in models that describe neuronal behavior. Here we develop and apply a direct gradient-based optimization algorithm to find stimulus waveforms that elicit a change in neuronal state while minimizing energy usage. We analyze standard models of neuronal behavior, the Hodgkin-Huxley and FitzHugh-Nagumo models, to show that the gradient-based algorithm: (1) enables automated exploration of a wide solution space, using stochastically generated initial waveforms that converge to multiple locally optimal solutions; and (2) finds optimal stimulus waveforms that achieve a physiological outcome condition, without a priori knowledge of the optimal terminal condition of all state variables. Analysis of biological systems using stochastically-seeded gradient methods can reveal salient dynamical mechanisms underlying the optimal control of system behavior. The gradient algorithm may also have practical applications in future work, for example, finding energy optimal waveforms for therapeutic neural stimulation that minimizes power usage and diminishes off-target effects and damage to neighboring tissue.
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Construction schedules slack time minimizing
NASA Astrophysics Data System (ADS)
Krzemiński, Michał
2017-07-01
The article presents two copyright models for minimizing downtime working brigades. Models have been developed for construction schedules performed using the method of work uniform. Application of flow shop models is possible and useful for the implementation of large objects, which can be divided into plots. The article also presents a condition describing gives which model should be used, as well as a brief example of optimization schedule. The optimization results confirm the legitimacy of the work on the newly-developed models.
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NASA Astrophysics Data System (ADS)
Liu, Hongcheng; Dong, Peng; Xing, Lei
2017-08-01
{{\\ell }2,1} -minimization-based sparse optimization was employed to solve the beam angle optimization (BAO) in intensity-modulated radiation therapy (IMRT) planning. The technique approximates the exact BAO formulation with efficiently computable convex surrogates, leading to plans that are inferior to those attainable with recently proposed gradient-based greedy schemes. In this paper, we alleviate/reduce the nontrivial inconsistencies between the {{\\ell }2,1} -based formulations and the exact BAO model by proposing a new sparse optimization framework based on the most recent developments in group variable selection. We propose the incorporation of the group-folded concave penalty (gFCP) as a substitution to the {{\\ell }2,1} -minimization framework. The new formulation is then solved by a variation of an existing gradient method. The performance of the proposed scheme is evaluated by both plan quality and the computational efficiency using three IMRT cases: a coplanar prostate case, a coplanar head-and-neck case, and a noncoplanar liver case. Involved in the evaluation are two alternative schemes: the {{\\ell }2,1} -minimization approach and the gradient norm method (GNM). The gFCP-based scheme outperforms both counterpart approaches. In particular, gFCP generates better plans than those obtained using the {{\\ell }2,1} -minimization for all three cases with a comparable computation time. As compared to the GNM, the gFCP improves both the plan quality and computational efficiency. The proposed gFCP-based scheme provides a promising framework for BAO and promises to improve both planning time and plan quality.
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Liu, Hongcheng; Dong, Peng; Xing, Lei
2017-07-20
[Formula: see text]-minimization-based sparse optimization was employed to solve the beam angle optimization (BAO) in intensity-modulated radiation therapy (IMRT) planning. The technique approximates the exact BAO formulation with efficiently computable convex surrogates, leading to plans that are inferior to those attainable with recently proposed gradient-based greedy schemes. In this paper, we alleviate/reduce the nontrivial inconsistencies between the [Formula: see text]-based formulations and the exact BAO model by proposing a new sparse optimization framework based on the most recent developments in group variable selection. We propose the incorporation of the group-folded concave penalty (gFCP) as a substitution to the [Formula: see text]-minimization framework. The new formulation is then solved by a variation of an existing gradient method. The performance of the proposed scheme is evaluated by both plan quality and the computational efficiency using three IMRT cases: a coplanar prostate case, a coplanar head-and-neck case, and a noncoplanar liver case. Involved in the evaluation are two alternative schemes: the [Formula: see text]-minimization approach and the gradient norm method (GNM). The gFCP-based scheme outperforms both counterpart approaches. In particular, gFCP generates better plans than those obtained using the [Formula: see text]-minimization for all three cases with a comparable computation time. As compared to the GNM, the gFCP improves both the plan quality and computational efficiency. The proposed gFCP-based scheme provides a promising framework for BAO and promises to improve both planning time and plan quality.
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Fast Algorithms for Designing Unimodular Waveform(s) With Good Correlation Properties
NASA Astrophysics Data System (ADS)
Li, Yongzhe; Vorobyov, Sergiy A.
2018-03-01
In this paper, we develop new fast and efficient algorithms for designing single/multiple unimodular waveforms/codes with good auto- and cross-correlation or weighted correlation properties, which are highly desired in radar and communication systems. The waveform design is based on the minimization of the integrated sidelobe level (ISL) and weighted ISL (WISL) of waveforms. As the corresponding optimization problems can quickly grow to large scale with increasing the code length and number of waveforms, the main issue turns to be the development of fast large-scale optimization techniques. The difficulty is also that the corresponding optimization problems are non-convex, but the required accuracy is high. Therefore, we formulate the ISL and WISL minimization problems as non-convex quartic optimization problems in frequency domain, and then simplify them into quadratic problems by utilizing the majorization-minimization technique, which is one of the basic techniques for addressing large-scale and/or non-convex optimization problems. While designing our fast algorithms, we find out and use inherent algebraic structures in the objective functions to rewrite them into quartic forms, and in the case of WISL minimization, to derive additionally an alternative quartic form which allows to apply the quartic-quadratic transformation. Our algorithms are applicable to large-scale unimodular waveform design problems as they are proved to have lower or comparable computational burden (analyzed theoretically) and faster convergence speed (confirmed by comprehensive simulations) than the state-of-the-art algorithms. In addition, the waveforms designed by our algorithms demonstrate better correlation properties compared to their counterparts.
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Optimum shape control of flexible beams by piezo-electric actuators
NASA Technical Reports Server (NTRS)
Baz, A.; Poh, S.
1987-01-01
The utilization of piezoelectric actuators in controlling the static deformation and shape of flexible beams is examined. An optimum design procedure is presented to enable the selection of the optimal location, thickness and excitation voltage of the piezoelectric actuators in a way that would minimize the deflection of the beam to which these actuators are bonded. Numerical examples are presented to illustrate the application of the developed optimization procedure in minimizing structural deformation of beams using ceramic and polymeric piezoelectric actuators bonded to the beams with a typical bonding agent. The obtained results emphasize the importance of the devised rational produce in designing beam-actuator systems with minimal elastic distortions.
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Static deflection control of flexible beams by piezo-electric actuators
NASA Technical Reports Server (NTRS)
Baz, A. M.
1986-01-01
This study deals with the utilization of piezo-electric actuators in controlling the static deformation of flexible beams. An optimum design procedure is presented to enable the selection of the optimal location, thickness and excitation voltage of the piezo-electric actuators in a way that would minimize the deflection of the beam to which these actuators are bonded. Numerical examples are presented to illustrate the application of the developed optimization procedure in minimizing the structural deformation of beams of different materials when subjected to different loading and end conditions using ceramic or polymeric piezo-electric actuators. The results obtained emphasize the importance of the devised rational procedure in designing beam-actuator systems with minimal elastic distortions.
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NASA Astrophysics Data System (ADS)
Venkateswara Rao, B.; Kumar, G. V. Nagesh; Chowdary, D. Deepak; Bharathi, M. Aruna; Patra, Stutee
2017-07-01
This paper furnish the new Metaheuristic algorithm called Cuckoo Search Algorithm (CSA) for solving optimal power flow (OPF) problem with minimization of real power generation cost. The CSA is found to be the most efficient algorithm for solving single objective optimal power flow problems. The CSA performance is tested on IEEE 57 bus test system with real power generation cost minimization as objective function. Static VAR Compensator (SVC) is one of the best shunt connected device in the Flexible Alternating Current Transmission System (FACTS) family. It has capable of controlling the voltage magnitudes of buses by injecting the reactive power to system. In this paper SVC is integrated in CSA based Optimal Power Flow to optimize the real power generation cost. SVC is used to improve the voltage profile of the system. CSA gives better results as compared to genetic algorithm (GA) in both without and with SVC conditions.
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Optimization of Operations Resources via Discrete Event Simulation Modeling
NASA Technical Reports Server (NTRS)
Joshi, B.; Morris, D.; White, N.; Unal, R.
1996-01-01
The resource levels required for operation and support of reusable launch vehicles are typically defined through discrete event simulation modeling. Minimizing these resources constitutes an optimization problem involving discrete variables and simulation. Conventional approaches to solve such optimization problems involving integer valued decision variables are the pattern search and statistical methods. However, in a simulation environment that is characterized by search spaces of unknown topology and stochastic measures, these optimization approaches often prove inadequate. In this paper, we have explored the applicability of genetic algorithms to the simulation domain. Genetic algorithms provide a robust search strategy that does not require continuity and differentiability of the problem domain. The genetic algorithm successfully minimized the operation and support activities for a space vehicle, through a discrete event simulation model. The practical issues associated with simulation optimization, such as stochastic variables and constraints, were also taken into consideration.
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NASA Astrophysics Data System (ADS)
Javad Kazemzadeh-Parsi, Mohammad; Daneshmand, Farhang; Ahmadfard, Mohammad Amin; Adamowski, Jan; Martel, Richard
2015-01-01
In the present study, an optimization approach based on the firefly algorithm (FA) is combined with a finite element simulation method (FEM) to determine the optimum design of pump and treat remediation systems. Three multi-objective functions in which pumping rate and clean-up time are design variables are considered and the proposed FA-FEM model is used to minimize operating costs, total pumping volumes and total pumping rates in three scenarios while meeting water quality requirements. The groundwater lift and contaminant concentration are also minimized through the optimization process. The obtained results show the applicability of the FA in conjunction with the FEM for the optimal design of groundwater remediation systems. The performance of the FA is also compared with the genetic algorithm (GA) and the FA is found to have a better convergence rate than the GA.
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Optimality Principles for Model-Based Prediction of Human Gait
Ackermann, Marko; van den Bogert, Antonie J.
2010-01-01
Although humans have a large repertoire of potential movements, gait patterns tend to be stereotypical and appear to be selected according to optimality principles such as minimal energy. When applied to dynamic musculoskeletal models such optimality principles might be used to predict how a patient’s gait adapts to mechanical interventions such as prosthetic devices or surgery. In this paper we study the effects of different performance criteria on predicted gait patterns using a 2D musculoskeletal model. The associated optimal control problem for a family of different cost functions was solved utilizing the direct collocation method. It was found that fatigue-like cost functions produced realistic gait, with stance phase knee flexion, as opposed to energy-related cost functions which avoided knee flexion during the stance phase. We conclude that fatigue minimization may be one of the primary optimality principles governing human gait. PMID:20074736
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Schiffmann, Christoph; Sebastiani, Daniel
2011-05-10
We present an algorithmic extension of a numerical optimization scheme for analytic capping potentials for use in mixed quantum-classical (quantum mechanical/molecular mechanical, QM/MM) ab initio calculations. Our goal is to minimize bond-cleavage-induced perturbations in the electronic structure, measured by means of a suitable penalty functional. The optimization algorithm-a variant of the artificial bee colony (ABC) algorithm, which relies on swarm intelligence-couples deterministic (downhill gradient) and stochastic elements to avoid local minimum trapping. The ABC algorithm outperforms the conventional downhill gradient approach, if the penalty hypersurface exhibits wiggles that prevent a straight minimization pathway. We characterize the optimized capping potentials by computing NMR chemical shifts. This approach will increase the accuracy of QM/MM calculations of complex biomolecules.
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Balancing on tightropes and slacklines
Paoletti, P.; Mahadevan, L.
2012-01-01
Balancing on a tightrope or a slackline is an example of a neuromechanical task where the whole body both drives and responds to the dynamics of the external environment, often on multiple timescales. Motivated by a range of neurophysiological observations, here we formulate a minimal model for this system and use optimal control theory to design a strategy for maintaining an upright position. Our analysis of the open and closed-loop dynamics shows the existence of an optimal rope sag where balancing requires minimal effort, consistent with qualitative observations and suggestive of strategies for optimizing balancing performance while standing and walking. Our consideration of the effects of nonlinearities, potential parameter coupling and delays on the overall performance shows that although these factors change the results quantitatively, the existence of an optimal strategy persists. PMID:22513724
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Research on Collection System Optimal Design of Wind Farm with Obstacles
NASA Astrophysics Data System (ADS)
Huang, W.; Yan, B. Y.; Tan, R. S.; Liu, L. F.
2017-05-01
To the collection system optimal design of offshore wind farm, the factors considered are not only the reasonable configuration of the cable and switch, but also the influence of the obstacles on the topology design of the offshore wind farm. This paper presents a concrete topology optimization algorithm with obstacles. The minimal area rectangle encasing box of the obstacle is obtained by using the method of minimal area encasing box. Then the optimization algorithm combining the advantages of Dijkstra algorithm and Prim algorithm is used to gain the scheme of avoidance obstacle path planning. Finally a fuzzy comprehensive evaluation model based on the analytic hierarchy process is constructed to compare the performance of the different topologies. Case studies demonstrate the feasibility of the proposed algorithm and model.
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Truss topology optimization with simultaneous analysis and design
NASA Technical Reports Server (NTRS)
Sankaranarayanan, S.; Haftka, Raphael T.; Kapania, Rakesh K.
1992-01-01
Strategies for topology optimization of trusses for minimum weight subject to stress and displacement constraints by Simultaneous Analysis and Design (SAND) are considered. The ground structure approach is used. A penalty function formulation of SAND is compared with an augmented Lagrangian formulation. The efficiency of SAND in handling combinations of general constraints is tested. A strategy for obtaining an optimal topology by minimizing the compliance of the truss is compared with a direct weight minimization solution to satisfy stress and displacement constraints. It is shown that for some problems, starting from the ground structure and using SAND is better than starting from a minimum compliance topology design and optimizing only the cross sections for minimum weight under stress and displacement constraints. A member elimination strategy to save CPU time is discussed.
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Optimization of motion control laws for tether crawler or elevator systems
NASA Technical Reports Server (NTRS)
Swenson, Frank R.; Von Tiesenhausen, Georg
1988-01-01
Based on the proposal of a motion control law by Lorenzini (1987), a method is developed for optimizing motion control laws for tether crawler or elevator systems in terms of the performance measures of travel time, the smoothness of acceleration and deceleration, and the maximum values of velocity and acceleration. The Lorenzini motion control law, based on powers of the hyperbolic tangent function, is modified by the addition of a constant-velocity section, and this modified function is then optimized by parameter selections to minimize the peak acceleration value for a selected travel time or to minimize travel time for the selected peak values of velocity and acceleration. It is shown that the addition of a constant-velocity segment permits further optimization of the motion control law performance.
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The Advantages of Collimator Optimization for Intensity Modulated Radiation Therapy
NASA Astrophysics Data System (ADS)
Doozan, Brian
The goal of this study was to improve dosimetry for pelvic, lung, head and neck, and other cancers sites with aspherical planning target volumes (PTV) using a new algorithm for collimator optimization for intensity modulated radiation therapy (IMRT) that minimizes the x-jaw gap (CAX) and the area of the jaws (CAA) for each treatment field. A retroactive study on the effects of collimator optimization of 20 patients was performed by comparing metric results for new collimator optimization techniques in Eclipse version 11.0. Keeping all other parameters equal, multiple plans are created using four collimator techniques: CA 0, all fields have collimators set to 0°, CAE, using the Eclipse collimator optimization, CAA, minimizing the area of the jaws around the PTV, and CAX, minimizing the x-jaw gap. The minimum area and the minimum x-jaw angles are found by evaluating each field beam's eye view of the PTV with ImageJ and finding the desired parameters with a custom script. The evaluation of the plans included the monitor units (MU), the maximum dose of the plan, the maximum dose to organs at risk (OAR), the conformity index (CI) and the number of fields that are calculated to split. Compared to the CA0 plans, the monitor units decreased on average by 6% for the CAX method with a p-value of 0.01 from an ANOVA test. The average maximum dose remained within 1.1% difference between all four methods with the lowest given by CAX. The maximum dose to the most at risk organ was best spared by the CAA method, which decreased by 0.62% compared to the CA0. Minimizing the x-jaws significantly reduced the number of split fields from 61 to 37. In every metric tested the CAX optimization produced comparable or superior results compared to the other three techniques. For aspherical PTVs, CAX on average reduced the number of split fields, lowered the maximum dose, minimized the dose to the surrounding OAR, and decreased the monitor units. This is achieved while maintaining the same control of the PTV.
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Multi-disciplinary optimization of aeroservoelastic systems
NASA Technical Reports Server (NTRS)
Karpel, Mordechay
1990-01-01
Efficient analytical and computational tools for simultaneous optimal design of the structural and control components of aeroservoelastic systems are presented. The optimization objective is to achieve aircraft performance requirements and sufficient flutter and control stability margins with a minimal weight penalty and without violating the design constraints. Analytical sensitivity derivatives facilitate an efficient optimization process which allows a relatively large number of design variables. Standard finite element and unsteady aerodynamic routines are used to construct a modal data base. Minimum State aerodynamic approximations and dynamic residualization methods are used to construct a high accuracy, low order aeroservoelastic model. Sensitivity derivatives of flutter dynamic pressure, control stability margins and control effectiveness with respect to structural and control design variables are presented. The performance requirements are utilized by equality constraints which affect the sensitivity derivatives. A gradient-based optimization algorithm is used to minimize an overall cost function. A realistic numerical example of a composite wing with four controls is used to demonstrate the modeling technique, the optimization process, and their accuracy and efficiency.
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Multidisciplinary optimization of aeroservoelastic systems using reduced-size models
NASA Technical Reports Server (NTRS)
Karpel, Mordechay
1992-01-01
Efficient analytical and computational tools for simultaneous optimal design of the structural and control components of aeroservoelastic systems are presented. The optimization objective is to achieve aircraft performance requirements and sufficient flutter and control stability margins with a minimal weight penalty and without violating the design constraints. Analytical sensitivity derivatives facilitate an efficient optimization process which allows a relatively large number of design variables. Standard finite element and unsteady aerodynamic routines are used to construct a modal data base. Minimum State aerodynamic approximations and dynamic residualization methods are used to construct a high accuracy, low order aeroservoelastic model. Sensitivity derivatives of flutter dynamic pressure, control stability margins and control effectiveness with respect to structural and control design variables are presented. The performance requirements are utilized by equality constraints which affect the sensitivity derivatives. A gradient-based optimization algorithm is used to minimize an overall cost function. A realistic numerical example of a composite wing with four controls is used to demonstrate the modeling technique, the optimization process, and their accuracy and efficiency.
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Reduction of shock induced noise in imperfectly expanded supersonic jets using convex optimization
NASA Astrophysics Data System (ADS)
Adhikari, Sam
2007-11-01
Imperfectly expanded jets generate screech noise. The imbalance between the backpressure and the exit pressure of the imperfectly expanded jets produce shock cells and expansion or compression waves from the nozzle. The instability waves and the shock cells interact to generate the screech sound. The mathematical model consists of cylindrical coordinate based full Navier-Stokes equations and large-eddy-simulation turbulence modeling. Analytical and computational analysis of the three-dimensional helical effects provide a model that relates several parameters with shock cell patterns, screech frequency and distribution of shock generation locations. Convex optimization techniques minimize the shock cell patterns and the instability waves. The objective functions are (convex) quadratic and the constraint functions are affine. In the quadratic optimization programs, minimization of the quadratic functions over a set of polyhedrons provides the optimal result. Various industry standard methods like regression analysis, distance between polyhedra, bounding variance, Markowitz optimization, and second order cone programming is used for Quadratic Optimization.
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Optimization of entanglement witnesses
NASA Astrophysics Data System (ADS)
Lewenstein, M.; Kraus, B.; Cirac, J. I.; Horodecki, P.
2000-11-01
An entanglement witness (EW) is an operator that allows the detection of entangled states. We give necessary and sufficient conditions for such operators to be optimal, i.e., to detect entangled states in an optimal way. We show how to optimize general EW, and then we particularize our results to the nondecomposable ones; the latter are those that can detect positive partial transpose entangled states (PPTES's). We also present a method to systematically construct and optimize this last class of operators based on the existence of ``edge'' PPTES's, i.e., states that violate the range separability criterion [Phys. Lett. A 232, 333 (1997)] in an extreme manner. This method also permits a systematic construction of nondecomposable positive maps (PM's). Our results lead to a sufficient condition for entanglement in terms of nondecomposable EW's and PM's. Finally, we illustrate our results by constructing optimal EW acting on H=C2⊗C4. The corresponding PM's constitute examples of PM's with minimal ``qubit'' domains, or-equivalently-minimal Hermitian conjugate codomains.
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Application of Sequential Quadratic Programming to Minimize Smart Active Flap Rotor Hub Loads
NASA Technical Reports Server (NTRS)
Kottapalli, Sesi; Leyland, Jane
2014-01-01
In an analytical study, SMART active flap rotor hub loads have been minimized using nonlinear programming constrained optimization methodology. The recently developed NLPQLP system (Schittkowski, 2010) that employs Sequential Quadratic Programming (SQP) as its core algorithm was embedded into a driver code (NLP10x10) specifically designed to minimize active flap rotor hub loads (Leyland, 2014). Three types of practical constraints on the flap deflections have been considered. To validate the current application, two other optimization methods have been used: i) the standard, linear unconstrained method, and ii) the nonlinear Generalized Reduced Gradient (GRG) method with constraints. The new software code NLP10x10 has been systematically checked out. It has been verified that NLP10x10 is functioning as desired. The following are briefly covered in this paper: relevant optimization theory; implementation of the capability of minimizing a metric of all, or a subset, of the hub loads as well as the capability of using all, or a subset, of the flap harmonics; and finally, solutions for the SMART rotor. The eventual goal is to implement NLP10x10 in a real-time wind tunnel environment.
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Fully localised nonlinear energy growth optimals in pipe flow
DOE Office of Scientific and Technical Information (OSTI.GOV)
Pringle, Chris C. T.; Willis, Ashley P.; Kerswell, Rich R.
A new, fully localised, energy growth optimal is found over large times and in long pipe domains at a given mass flow rate. This optimal emerges at a threshold disturbance energy below which a nonlinear version of the known (streamwise-independent) linear optimal [P. J. Schmid and D. S. Henningson, “Optimal energy density growth in Hagen-Poiseuille flow,” J. Fluid Mech. 277, 192–225 (1994)] is selected and appears to remain the optimal up until the critical energy at which transition is triggered. The form of this optimal is similar to that found in short pipes [Pringle et al., “Minimal seeds for shearmore » flow turbulence: Using nonlinear transient growth to touch the edge of chaos,” J. Fluid Mech. 702, 415–443 (2012)], but now with full localisation in the streamwise direction. This fully localised optimal perturbation represents the best approximation yet of the minimal seed (the smallest perturbation which is arbitrarily close to states capable of triggering a turbulent episode) for “real” (laboratory) pipe flows. Dependence of the optimal with respect to several parameters has been computed and establishes that the structure is robust.« less
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Estimating Optimal Transformations for Multiple Regression and Correlation.
1982-07-01
algorithm; we minimize (2.4) e2 (,,, ...,) = E[e(Y) - 1I (X 2 j=l j 2holding EO =1, E6 = E0, =.-. =Ecp = 0, through a series of single function minimizations...X, x = INU = lIVe . Then (5.16) THEOREM. If 6*, p* is an optimal transformation for regression, then = ue*o Conversely, if e satisfies Xe = U6, Nll1...Stanford University, Tech. Report ORIONOO6. Gasser, T. and Rosenblatt, M. (eds.) (1979). Smoothing Techniques for Curve Estimation, in Lecture Notes in
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AMMOS2: a web server for protein-ligand-water complexes refinement via molecular mechanics.
Labbé, Céline M; Pencheva, Tania; Jereva, Dessislava; Desvillechabrol, Dimitri; Becot, Jérôme; Villoutreix, Bruno O; Pajeva, Ilza; Miteva, Maria A
2017-07-03
AMMOS2 is an interactive web server for efficient computational refinement of protein-small organic molecule complexes. The AMMOS2 protocol employs atomic-level energy minimization of a large number of experimental or modeled protein-ligand complexes. The web server is based on the previously developed standalone software AMMOS (Automatic Molecular Mechanics Optimization for in silico Screening). AMMOS utilizes the physics-based force field AMMP sp4 and performs optimization of protein-ligand interactions at five levels of flexibility of the protein receptor. The new version 2 of AMMOS implemented in the AMMOS2 web server allows the users to include explicit water molecules and individual metal ions in the protein-ligand complexes during minimization. The web server provides comprehensive analysis of computed energies and interactive visualization of refined protein-ligand complexes. The ligands are ranked by the minimized binding energies allowing the users to perform additional analysis for drug discovery or chemical biology projects. The web server has been extensively tested on 21 diverse protein-ligand complexes. AMMOS2 minimization shows consistent improvement over the initial complex structures in terms of minimized protein-ligand binding energies and water positions optimization. The AMMOS2 web server is freely available without any registration requirement at the URL: http://drugmod.rpbs.univ-paris-diderot.fr/ammosHome.php. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.
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AMMOS2: a web server for protein–ligand–water complexes refinement via molecular mechanics
Labbé, Céline M.; Pencheva, Tania; Jereva, Dessislava; Desvillechabrol, Dimitri; Becot, Jérôme; Villoutreix, Bruno O.; Pajeva, Ilza
2017-01-01
Abstract AMMOS2 is an interactive web server for efficient computational refinement of protein–small organic molecule complexes. The AMMOS2 protocol employs atomic-level energy minimization of a large number of experimental or modeled protein–ligand complexes. The web server is based on the previously developed standalone software AMMOS (Automatic Molecular Mechanics Optimization for in silico Screening). AMMOS utilizes the physics-based force field AMMP sp4 and performs optimization of protein–ligand interactions at five levels of flexibility of the protein receptor. The new version 2 of AMMOS implemented in the AMMOS2 web server allows the users to include explicit water molecules and individual metal ions in the protein–ligand complexes during minimization. The web server provides comprehensive analysis of computed energies and interactive visualization of refined protein–ligand complexes. The ligands are ranked by the minimized binding energies allowing the users to perform additional analysis for drug discovery or chemical biology projects. The web server has been extensively tested on 21 diverse protein–ligand complexes. AMMOS2 minimization shows consistent improvement over the initial complex structures in terms of minimized protein–ligand binding energies and water positions optimization. The AMMOS2 web server is freely available without any registration requirement at the URL: http://drugmod.rpbs.univ-paris-diderot.fr/ammosHome.php. PMID:28486703
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The SMO-COIN Nexus: Using Social Movement Theory to Demobilize Insurgency
2009-06-01
with the Darul Islam movement.222 The founders, Abdullah Sungkar and Abu Bakar Ba’asyir, developed a difference of opinion with the Darul Islam...Whether Sungkar attended this seminar is unclear but it is about this same time that Sungkar died and was replaced as JI emir by Abu Bakar Ba’asyir...Indonesia (MMI) Abu Bakar Ba’asyir organized the “first national congress of mujahidin”266 in Yogyakarta, Indonesia in August 5-7, 2000 to bring
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Minimum Lethal Concentrations, Symptomatology, and Pathology of Phosgene
1923-09-15
svewd 1007 6.s5 besovared 740 9.17 Died after 42owl* 1101 Ve" t a4 j AT sv.on U24,3.5 gel 6 8 J965 50 9.17 " 4 74 1106 3.1" JAeovered 1120 10.15 of...be bUeo-tW4. ASAa tW beg dIeS in @,owm) nai oinuliomme When AoP omie for three of four Am" the Linseehe In 1W eyes mind aso ftontiy beso smo-Peu
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Monte Carlo sensitivity analysis of EUV mask reflectivity and its impact on OPC accuracy
NASA Astrophysics Data System (ADS)
Chen, Yulu; Wood, Obert; Rankin, Jed; Gullikson, Eric; Meyer-Ilse, Julia; Sun, Lei; Qi, Zhengqing John; Goodwin, Francis; Kye, Jongwook
2017-03-01
Unlike optical masks which are transmissive optical elements, use of extreme ultraviolet (EUV) radiation requires a reflective mask structure - a multi-layer coating consisting of alternating layers of high-Z (wave impedance) and low-Z materials that provide enhanced reflectivity over a narrow wavelength band peaked at the Bragg wavelength.1 Absorber side wall angle, corner rounding,2 surface roughness,3 and defects4 affect mask performance, but even seemingly simple parameters like bulk reflectivity on mirror and absorber surfaces can have a profound influence on imaging. For instance, using inaccurate reflectivity values at small and large incident angles would diminish the benefits of source mask co-optimization (SMO) and result in larger than expected pattern shifts. The goal of our work is to calculate the variation in mask reflectivity due to various sources of inaccuracies using Monte Carlo simulations. Such calculation is necessary as small changes in the thickness and optical properties of the high-Z and low-Z materials can cause substantial variations in reflectivity. This is further complicated by undesirable intermixing between the two materials used to create the reflector.5 One of the key contributors to mask reflectivity fluctuation is identified to be the intermixing layer thickness. We also investigate the impacts on OPC when the wrong mask information is provided, and evaluate the deterioration of overlapping process window. For a hypothetical N7 via layer, the lack of accurate mask information costs 25% of the depth of focus at 5% exposure latitude. Our work would allow the determination of major contributors to mask reflectivity variation, drive experimental efforts of measuring such contributors, provide strategies to optimize mask reflectivity, and quantize the OPC errors due to imperfect mask modeling.
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Jerk Minimization Method for Vibration Control in Buildings
NASA Technical Reports Server (NTRS)
Abatan, Ayo O.; Yao, Leummim
1997-01-01
In many vibration minimization control problems for high rise buildings subject to strong earthquake loads, the emphasis has been on a combination of minimizing the displacement, the velocity and the acceleration of the motion of the building. In most cases, the accelerations that are involved are not necessarily large but the change in them (jerk) are abrupt. These changes in magnitude or direction are responsible for most building damage and also create discomfort like motion sickness for inhabitants of these structures because of the element of surprise. We propose a method of minimizing also the jerk which is the sudden change in acceleration or the derivative of the acceleration using classical linear quadratic optimal controls. This was done through the introduction of a quadratic performance index involving the cost due to the jerk; a special change of variable; and using the jerk as a control variable. The values of the optimal control are obtained using the Riccati equation.
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On the Run-Time Optimization of the Boolean Logic of a Program.
ERIC Educational Resources Information Center
Cadolino, C.; Guazzo, M.
1982-01-01
Considers problem of optimal scheduling of Boolean expression (each Boolean variable represents binary outcome of program module) on single-processor system. Optimization discussed consists of finding operand arrangement that minimizes average execution costs representing consumption of resources (elapsed time, main memory, number of…
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Fitting Nonlinear Curves by use of Optimization Techniques
NASA Technical Reports Server (NTRS)
Hill, Scott A.
2005-01-01
MULTIVAR is a FORTRAN 77 computer program that fits one of the members of a set of six multivariable mathematical models (five of which are nonlinear) to a multivariable set of data. The inputs to MULTIVAR include the data for the independent and dependent variables plus the user s choice of one of the models, one of the three optimization engines, and convergence criteria. By use of the chosen optimization engine, MULTIVAR finds values for the parameters of the chosen model so as to minimize the sum of squares of the residuals. One of the optimization engines implements a routine, developed in 1982, that utilizes the Broydon-Fletcher-Goldfarb-Shanno (BFGS) variable-metric method for unconstrained minimization in conjunction with a one-dimensional search technique that finds the minimum of an unconstrained function by polynomial interpolation and extrapolation without first finding bounds on the solution. The second optimization engine is a faster and more robust commercially available code, denoted Design Optimization Tool, that also uses the BFGS method. The third optimization engine is a robust and relatively fast routine that implements the Levenberg-Marquardt algorithm.
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Evolutionary Bi-objective Optimization for Bulldozer and Its Blade in Soil Cutting
NASA Astrophysics Data System (ADS)
Sharma, Deepak; Barakat, Nada
2018-02-01
An evolutionary optimization approach is adopted in this paper for simultaneously achieving the economic and productive soil cutting. The economic aspect is defined by minimizing the power requirement from the bulldozer, and the soil cutting is made productive by minimizing the time of soil cutting. For determining the power requirement, two force models are adopted from the literature to quantify the cutting force on the blade. Three domain-specific constraints are also proposed, which are limiting the power from the bulldozer, limiting the maximum force on the bulldozer blade and achieving the desired production rate. The bi-objective optimization problem is solved using five benchmark multi-objective evolutionary algorithms and one classical optimization technique using the ɛ-constraint method. The Pareto-optimal solutions are obtained with the knee-region. Further, the post-optimal analysis is performed on the obtained solutions to decipher relationships among the objectives and decision variables. Such relationships are later used for making guidelines for selecting the optimal set of input parameters. The obtained results are then compared with the experiment results from the literature that show a close agreement among them.
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Comparison of Low-Thrust Control Laws for Application in Planetocentric Space
NASA Technical Reports Server (NTRS)
Falck, Robert D.; Sjauw, Waldy K.; Smith, David A.
2014-01-01
Recent interest at NASA for the application of solar electric propulsion for the transfer of significant payloads in cislunar space has led to the development of high-fidelity simulations of such missions. With such transfers involving transfer times on the order of months, simulation time can be significant. In the past, the examination of such missions typically began with the use of lower-fidelity trajectory optimization tools such as SEPSPOT to develop and tune guidance laws which delivered optimal or near- optimal trajectories, where optimal is generally defined as minimizing propellant expenditure or time of flight. The transfer of these solutions to a high-fidelity simulation is typically an iterative process whereby the initial solution may nearly, but not precisely, meet mission objectives. Further tuning of the guidance algorithm is typically necessary when accounting for high-fidelity perturbations such as those due to more detailed gravity models, secondary-body effects, solar radiation pressure, etc. While trajectory optimization is a useful method for determining optimal performance metrics, algorithms which deliver nearly optimal performance with minimal tuning are an attractive alternative.
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Two hybrid compaction algorithms for the layout optimization problem.
Xiao, Ren-Bin; Xu, Yi-Chun; Amos, Martyn
2007-01-01
In this paper we present two new algorithms for the layout optimization problem: this concerns the placement of circular, weighted objects inside a circular container, the two objectives being to minimize imbalance of mass and to minimize the radius of the container. This problem carries real practical significance in industrial applications (such as the design of satellites), as well as being of significant theoretical interest. We present two nature-inspired algorithms for this problem, the first based on simulated annealing, and the second on particle swarm optimization. We compare our algorithms with the existing best-known algorithm, and show that our approaches out-perform it in terms of both solution quality and execution time.
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ONLINE MINIMIZATION OF VERTICAL BEAM SIZES AT APS
DOE Office of Scientific and Technical Information (OSTI.GOV)
Sun, Yipeng
In this paper, online minimization of vertical beam sizes along the APS (Advanced Photon Source) storage ring is presented. A genetic algorithm (GA) was developed and employed for the online optimization in the APS storage ring. A total of 59 families of skew quadrupole magnets were employed as knobs to adjust the coupling and the vertical dispersion in the APS storage ring. Starting from initially zero current skew quadrupoles, small vertical beam sizes along the APS storage ring were achieved in a short optimization time of one hour. The optimization results from this method are briefly compared with the onemore » from LOCO (Linear Optics from Closed Orbits) response matrix correction.« less
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Minimal residual method provides optimal regularization parameter for diffuse optical tomography
NASA Astrophysics Data System (ADS)
Jagannath, Ravi Prasad K.; Yalavarthy, Phaneendra K.
2012-10-01
The inverse problem in the diffuse optical tomography is known to be nonlinear, ill-posed, and sometimes under-determined, requiring regularization to obtain meaningful results, with Tikhonov-type regularization being the most popular one. The choice of this regularization parameter dictates the reconstructed optical image quality and is typically chosen empirically or based on prior experience. An automated method for optimal selection of regularization parameter that is based on regularized minimal residual method (MRM) is proposed and is compared with the traditional generalized cross-validation method. The results obtained using numerical and gelatin phantom data indicate that the MRM-based method is capable of providing the optimal regularization parameter.
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Minimal residual method provides optimal regularization parameter for diffuse optical tomography.
Jagannath, Ravi Prasad K; Yalavarthy, Phaneendra K
2012-10-01
The inverse problem in the diffuse optical tomography is known to be nonlinear, ill-posed, and sometimes under-determined, requiring regularization to obtain meaningful results, with Tikhonov-type regularization being the most popular one. The choice of this regularization parameter dictates the reconstructed optical image quality and is typically chosen empirically or based on prior experience. An automated method for optimal selection of regularization parameter that is based on regularized minimal residual method (MRM) is proposed and is compared with the traditional generalized cross-validation method. The results obtained using numerical and gelatin phantom data indicate that the MRM-based method is capable of providing the optimal regularization parameter.
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NASA Astrophysics Data System (ADS)
Trojková, Darina; Judas, Libor; Trojek, Tomáš
2014-11-01
Minimizing the late rectal toxicity of prostate cancer patients is a very important and widely-discussed topic. Normal tissue complication probability (NTCP) models can be used to evaluate competing treatment plans. In our work, the parameters of the Lyman-Kutcher-Burman (LKB), Källman, and Logit+EUD models are optimized by minimizing the Brier score for a group of 302 prostate cancer patients. The NTCP values are calculated and are compared with the values obtained using previously published values for the parameters. χ2 Statistics were calculated as a check of goodness of optimization.
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NASA Astrophysics Data System (ADS)
Kim, U.; Parker, J.
2016-12-01
Many dense non-aqueous phase liquid (DNAPL) contaminated sites in the U.S. are reported as "remediation in progress" (RIP). However, the cost to complete (CTC) remediation at these sites is highly uncertain and in many cases, the current remediation plan may need to be modified or replaced to achieve remediation objectives. This study evaluates the effectiveness of iterative stochastic cost optimization that incorporates new field data for periodic parameter recalibration to incrementally reduce prediction uncertainty and implement remediation design modifications as needed to minimize the life cycle cost (i.e., CTC). This systematic approach, using the Stochastic Cost Optimization Toolkit (SCOToolkit), enables early identification and correction of problems to stay on track for completion while minimizing the expected (i.e., probability-weighted average) CTC. This study considers a hypothetical site involving multiple DNAPL sources in an unconfined aquifer using thermal treatment for source reduction and electron donor injection for dissolved plume control. The initial design is based on stochastic optimization using model parameters and their joint uncertainty based on calibration to site characterization data. The model is periodically recalibrated using new monitoring data and performance data for the operating remediation systems. Projected future performance using the current remediation plan is assessed and reoptimization of operational variables for the current system or consideration of alternative designs are considered depending on the assessment results. We compare remediation duration and cost for the stepwise re-optimization approach with single stage optimization as well as with a non-optimized design based on typical engineering practice.
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Reactive power optimization strategy considering analytical impedance ratio
NASA Astrophysics Data System (ADS)
Wu, Zhongchao; Shen, Weibing; Liu, Jinming; Guo, Maoran; Zhang, Shoulin; Xu, Keqiang; Wang, Wanjun; Sui, Jinlong
2017-05-01
In this paper, considering the traditional reactive power optimization cannot realize the continuous voltage adjustment and voltage stability, a dynamic reactive power optimization strategy is proposed in order to achieve both the minimization of network loss and high voltage stability with wind power. Due to the fact that wind power generation is fluctuant and uncertain, electrical equipments such as transformers and shunt capacitors may be operated frequently in order to achieve minimization of network loss, which affect the lives of these devices. In order to solve this problem, this paper introduces the derivation process of analytical impedance ratio based on Thevenin equivalent. Thus, the multiple objective function is proposed to minimize the network loss and analytical impedance ratio. Finally, taking the improved IEEE 33-bus distribution system as example, the result shows that the movement of voltage control equipment has been reduced and network loss increment is controlled at the same time, which proves the applicable value of this strategy.
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Sato, Katsufumi; Shiomi, Kozue; Watanabe, Yuuki; Watanuki, Yutaka; Takahashi, Akinori; Ponganis, Paul J.
2010-01-01
It has been predicted that geometrically similar animals would swim at the same speed with stroke frequency scaling with mass−1/3. In the present study, morphological and behavioural data obtained from free-ranging penguins (seven species) were compared. Morphological measurements support the geometrical similarity. However, cruising speeds of 1.8–2.3 m s−1 were significantly related to mass0.08 and stroke frequencies were proportional to mass−0.29. These scaling relationships do not agree with the previous predictions for geometrically similar animals. We propose a theoretical model, considering metabolic cost, work against mechanical forces (drag and buoyancy), pitch angle and dive depth. This new model predicts that: (i) the optimal swim speed, which minimizes the energy cost of transport, is proportional to (basal metabolic rate/drag)1/3 independent of buoyancy, pitch angle and dive depth; (ii) the optimal speed is related to mass0.05; and (iii) stroke frequency is proportional to mass−0.28. The observed scaling relationships of penguins support these predictions, which suggest that breath-hold divers swam optimally to minimize the cost of transport, including mechanical and metabolic energy during dive. PMID:19906666
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Optimizing immobilized enzyme performance in cell-free environments to produce liquid fuels.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kumar, Sanat
The overall goal of this project was to optimize enzyme performance for the production of bio-diesel fuel. Enzyme immobilization has attracted much attention as a means to increase productivity. Mesorporous silica materials have been known to be best suited for immobilizing enzymes. A major challenge is to ensure that the enzymatic activity is retained after immobilization. Two major factors which drive enzymatic deactivation are protein-surface and inter-protein interactions. Previously, we studied protein stability inside pores and how to optimize protein-surface interactions to minimize protein denaturation. In this work we studied eh effect of surface curvature and chemistry on inter-protein interactions.more » Our goal was to find suitable immobilization supports which minimize these inter-protein interactions. Our studies carried out in the frame work of Hydrophobic-Polar (HP) model showed that enzymes immobilized inside hydrophobic pores of optimal sizes are best suited to minimize these inter-protein interactions. Besides, this study is also of biological importance to understand the role of chaperonins in protein disaggregation. Both of these aspects profited immensely with collaborations with our experimental colleague, Prof. Georges Belfort (RPI), who performed the experimental analog of our theoretical works.« less
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A multiobjective optimization algorithm is applied to a groundwater quality management problem involving remediation by pump-and-treat (PAT). The multiobjective optimization framework uses the niched Pareto genetic algorithm (NPGA) and is applied to simultaneously minimize the...
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NASA Astrophysics Data System (ADS)
Lee, Jeong-Eun; Gen, Mitsuo; Rhee, Kyong-Gu; Lee, Hee-Hyol
This paper deals with the building of the reusable reverse logistics model considering the decision of the backorder or the next arrival of goods. The optimization method to minimize the transportation cost and to minimize the volume of the backorder or the next arrival of goods occurred by the Just in Time delivery of the final delivery stage between the manufacturer and the processing center is proposed. Through the optimization algorithms using the priority-based genetic algorithm and the hybrid genetic algorithm, the sub-optimal delivery routes are determined. Based on the case study of a distilling and sale company in Busan in Korea, the new model of the reusable reverse logistics of empty bottles is built and the effectiveness of the proposed method is verified.
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Capital dissipation minimization for a class of complex irreversible resource exchange processes
NASA Astrophysics Data System (ADS)
Xia, Shaojun; Chen, Lingen
2017-05-01
A model of a class of irreversible resource exchange processes (REPes) between a firm and a producer with commodity flow leakage from the producer to a competitive market is established in this paper. The REPes are assumed to obey the linear commodity transfer law (LCTL). Optimal price paths for capital dissipation minimization (CDM) (it can measure economic process irreversibility) are obtained. The averaged optimal control theory is used. The optimal REP strategy is also compared with other strategies, such as constant-firm-price operation and constant-commodity-flow operation, and effects of the amount of commodity transferred and the commodity flow leakage on the optimal REP strategy are also analyzed. The commodity prices of both the producer and the firm for the CDM of the REPes with commodity flow leakage change with the time exponentially.
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NASA Astrophysics Data System (ADS)
Postnov, Sergey
2017-11-01
Two kinds of optimal control problem are investigated for linear time-invariant fractional-order systems with lumped parameters which dynamics described by equations with Hadamard-type derivative: the problem of control with minimal norm and the problem of control with minimal time at given restriction on control norm. The problem setting with nonlocal initial conditions studied. Admissible controls allowed to be the p-integrable functions (p > 1) at half-interval. The optimal control problem studied by moment method. The correctness and solvability conditions for the corresponding moment problem are derived. For several special cases the optimal control problems stated are solved analytically. Some analogies pointed for results obtained with the results which are known for integer-order systems and fractional-order systems describing by equations with Caputo- and Riemann-Liouville-type derivatives.
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Application of quadratic optimization to supersonic inlet control
NASA Technical Reports Server (NTRS)
Lehtinen, B.; Zeller, J. R.
1971-01-01
The application of linear stochastic optimal control theory to the design of the control system for the air intake (inlet) of a supersonic air-breathing propulsion system is discussed. The controls must maintain a stable inlet shock position in the presence of random airflow disturbances and prevent inlet unstart. Two different linear time invariant control systems are developed. One is designed to minimize a nonquadratic index, the expected frequency of inlet unstart, and the other is designed to minimize the mean square value of inlet shock motion. The quadratic equivalence principle is used to obtain the best linear controller that minimizes the nonquadratic performance index. The two systems are compared on the basis of unstart prevention, control effort requirements, and sensitivity to parameter variations.
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Permanent magnet design for magnetic heat pumps using total cost minimization
NASA Astrophysics Data System (ADS)
Teyber, R.; Trevizoli, P. V.; Christiaanse, T. V.; Govindappa, P.; Niknia, I.; Rowe, A.
2017-11-01
The active magnetic regenerator (AMR) is an attractive technology for efficient heat pumps and cooling systems. The costs associated with a permanent magnet for near room temperature applications are a central issue which must be solved for broad market implementation. To address this problem, we present a permanent magnet topology optimization to minimize the total cost of cooling using a thermoeconomic cost-rate balance coupled with an AMR model. A genetic algorithm identifies cost-minimizing magnet topologies. For a fixed temperature span of 15 K and 4.2 kg of gadolinium, the optimal magnet configuration provides 3.3 kW of cooling power with a second law efficiency (ηII) of 0.33 using 16.3 kg of permanent magnet material.
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Gazijahani, Farhad Samadi; Ravadanegh, Sajad Najafi; Salehi, Javad
2018-02-01
The inherent volatility and unpredictable nature of renewable generations and load demand pose considerable challenges for energy exchange optimization of microgrids (MG). To address these challenges, this paper proposes a new risk-based multi-objective energy exchange optimization for networked MGs from economic and reliability standpoints under load consumption and renewable power generation uncertainties. In so doing, three various risk-based strategies are distinguished by using conditional value at risk (CVaR) approach. The proposed model is specified as a two-distinct objective function. The first function minimizes the operation and maintenance costs, cost of power transaction between upstream network and MGs as well as power loss cost, whereas the second function minimizes the energy not supplied (ENS) value. Furthermore, the stochastic scenario-based approach is incorporated into the approach in order to handle the uncertainty. Also, Kantorovich distance scenario reduction method has been implemented to reduce the computational burden. Finally, non-dominated sorting genetic algorithm (NSGAII) is applied to minimize the objective functions simultaneously and the best solution is extracted by fuzzy satisfying method with respect to risk-based strategies. To indicate the performance of the proposed model, it is performed on the modified IEEE 33-bus distribution system and the obtained results show that the presented approach can be considered as an efficient tool for optimal energy exchange optimization of MGs. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.
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Program Aids Analysis And Optimization Of Design
NASA Technical Reports Server (NTRS)
Rogers, James L., Jr.; Lamarsh, William J., II
1994-01-01
NETS/ PROSSS (NETS Coupled With Programming System for Structural Synthesis) computer program developed to provide system for combining NETS (MSC-21588), neural-network application program and CONMIN (Constrained Function Minimization, ARC-10836), optimization program. Enables user to reach nearly optimal design. Design then used as starting point in normal optimization process, possibly enabling user to converge to optimal solution in significantly fewer iterations. NEWT/PROSSS written in C language and FORTRAN 77.
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Multi-level optimization of a beam-like space truss utilizing a continuum model
NASA Technical Reports Server (NTRS)
Yates, K.; Gurdal, Z.; Thangjitham, S.
1992-01-01
A continuous beam model is developed for approximate analysis of a large, slender, beam-like truss. The model is incorporated in a multi-level optimization scheme for the weight minimization of such trusses. This scheme is tested against traditional optimization procedures for savings in computational cost. Results from both optimization methods are presented for comparison.
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Optimization of USMC Hornet Inventory
2016-06-01
maintenance activities while adhering to the required number of aircraft for 22 operational use. He introduced an optimization based on an ILP... operational requirements across the entire planning process. In dealing with tail assignment as an optimization problem instead of a feasibility...aircraft and the goal is to minimize the penalties associated with failing to meet operational requirements. This research focuses on the optimal
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Zheng, Jingjing; Frisch, Michael J
2017-12-12
An efficient geometry optimization algorithm based on interpolated potential energy surfaces with iteratively updated Hessians is presented in this work. At each step of geometry optimization (including both minimization and transition structure search), an interpolated potential energy surface is properly constructed by using the previously calculated information (energies, gradients, and Hessians/updated Hessians), and Hessians of the two latest geometries are updated in an iterative manner. The optimized minimum or transition structure on the interpolated surface is used for the starting geometry of the next geometry optimization step. The cost of searching the minimum or transition structure on the interpolated surface and iteratively updating Hessians is usually negligible compared with most electronic structure single gradient calculations. These interpolated potential energy surfaces are often better representations of the true potential energy surface in a broader range than a local quadratic approximation that is usually used in most geometry optimization algorithms. Tests on a series of large and floppy molecules and transition structures both in gas phase and in solutions show that the new algorithm can significantly improve the optimization efficiency by using the iteratively updated Hessians and optimizations on interpolated surfaces.
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Multiobjective optimization of low impact development stormwater controls
NASA Astrophysics Data System (ADS)
Eckart, Kyle; McPhee, Zach; Bolisetti, Tirupati
2018-07-01
Green infrastructure such as Low Impact Development (LID) controls are being employed to manage the urban stormwater and restore the predevelopment hydrological conditions besides improving the stormwater runoff water quality. Since runoff generation and infiltration processes are nonlinear, there is a need for identifying optimal combination of LID controls. A coupled optimization-simulation model was developed by linking the U.S. EPA Stormwater Management Model (SWMM) to the Borg Multiobjective Evolutionary Algorithm (Borg MOEA). The coupled model is capable of performing multiobjective optimization which uses SWMM simulations as a tool to evaluate potential solutions to the optimization problem. The optimization-simulation tool was used to evaluate low impact development (LID) stormwater controls. A SWMM model was developed, calibrated, and validated for a sewershed in Windsor, Ontario and LID stormwater controls were tested for three different return periods. LID implementation strategies were optimized using the optimization-simulation model for five different implementation scenarios for each of the three storm events with the objectives of minimizing peak flow in the stormsewers, reducing total runoff, and minimizing cost. For the sewershed in Windsor, Ontario, the peak run off and total volume of the runoff were found to reduce by 13% and 29%, respectively.
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Pojić, Milica; Rakić, Dušan; Lazić, Zivorad
2015-01-01
A chemometric approach was applied for the optimization of the robustness of the NIRS method for wheat quality control. Due to the high number of experimental (n=6) and response variables to be studied (n=7) the optimization experiment was divided into two stages: screening stage in order to evaluate which of the considered variables were significant, and optimization stage to optimize the identified factors in the previously selected experimental domain. The significant variables were identified by using fractional factorial experimental design, whilst Box-Wilson rotatable central composite design (CCRD) was run to obtain the optimal values for the significant variables. The measured responses included: moisture, protein and wet gluten content, Zeleny sedimentation value and deformation energy. In order to achieve the minimal variation in responses, the optimal factor settings were found by minimizing the propagation of error (POE). The simultaneous optimization of factors was conducted by desirability function. The highest desirability of 87.63% was accomplished by setting up experimental conditions as follows: 19.9°C for sample temperature, 19.3°C for ambient temperature and 240V for instrument voltage. Copyright © 2014 Elsevier B.V. All rights reserved.
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Simultaneous multislice refocusing via time optimal control.
Rund, Armin; Aigner, Christoph Stefan; Kunisch, Karl; Stollberger, Rudolf
2018-02-09
Joint design of minimum duration RF pulses and slice-selective gradient shapes for MRI via time optimal control with strict physical constraints, and its application to simultaneous multislice imaging. The minimization of the pulse duration is cast as a time optimal control problem with inequality constraints describing the refocusing quality and physical constraints. It is solved with a bilevel method, where the pulse length is minimized in the upper level, and the constraints are satisfied in the lower level. To address the inherent nonconvexity of the optimization problem, the upper level is enhanced with new heuristics for finding a near global optimizer based on a second optimization problem. A large set of optimized examples shows an average temporal reduction of 87.1% for double diffusion and 74% for turbo spin echo pulses compared to power independent number of slices pulses. The optimized results are validated on a 3T scanner with phantom measurements. The presented design method computes minimum duration RF pulse and slice-selective gradient shapes subject to physical constraints. The shorter pulse duration can be used to decrease the effective echo time in existing echo-planar imaging or echo spacing in turbo spin echo sequences. © 2018 International Society for Magnetic Resonance in Medicine.
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Displacement based multilevel structural optimization
NASA Technical Reports Server (NTRS)
Striz, Alfred G.
1995-01-01
Multidisciplinary design optimization (MDO) is expected to play a major role in the competitive transportation industries of tomorrow, i.e., in the design of aircraft and spacecraft, of high speed trains, boats, and automobiles. All of these vehicles require maximum performance at minimum weight to keep fuel consumption low and conserve resources. Here, MDO can deliver mathematically based design tools to create systems with optimum performance subject to the constraints of disciplines such as structures, aerodynamics, controls, etc. Although some applications of MDO are beginning to surface, the key to a widespread use of this technology lies in the improvement of its efficiency. This aspect is investigated here for the MDO subset of structural optimization, i.e., for the weight minimization of a given structure under size, strength, and displacement constraints. Specifically, finite element based multilevel optimization of structures (here, statically indeterminate trusses and beams for proof of concept) is performed. In the system level optimization, the design variables are the coefficients of assumed displacement functions, and the load unbalance resulting from the solution of the stiffness equations is minimized. Constraints are placed on the deflection amplitudes and the weight of the structure. In the subsystems level optimizations, the weight of each element is minimized under the action of stress constraints, with the cross sectional dimensions as design variables. This approach is expected to prove very efficient, especially for complex structures, since the design task is broken down into a large number of small and efficiently handled subtasks, each with only a small number of variables. This partitioning will also allow for the use of parallel computing, first, by sending the system and subsystems level computations to two different processors, ultimately, by performing all subsystems level optimizations in a massively parallel manner on separate processors. It is expected that the subsystems level optimizations can be further improved through the use of controlled growth, a method which reduces an optimization to a more efficient analysis with only a slight degradation in accuracy. The efficiency of all proposed techniques is being evaluated relative to the performance of the standard single level optimization approach where the complete structure is weight minimized under the action of all given constraints by one processor and to the performance of simultaneous analysis and design which combines analysis and optimization into a single step. It is expected that the present approach can be expanded to include additional structural constraints (buckling, free and forced vibration, etc.) or other disciplines (passive and active controls, aerodynamics, etc.) for true MDO.
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Minimizing water consumption when producing hydropower
NASA Astrophysics Data System (ADS)
Leon, A. S.
2015-12-01
In 2007, hydropower accounted for only 16% of the world electricity production, with other renewable sources totaling 3%. Thus, it is not surprising that when alternatives are evaluated for new energy developments, there is strong impulse for fossil fuel or nuclear energy as opposed to renewable sources. However, as hydropower schemes are often part of a multipurpose water resources development project, they can often help to finance other components of the project. In addition, hydropower systems and their associated dams and reservoirs provide human well-being benefits, such as flood control and irrigation, and societal benefits such as increased recreational activities and improved navigation. Furthermore, hydropower due to its associated reservoir storage, can provide flexibility and reliability for energy production in integrated energy systems. The storage capability of hydropower systems act as a regulating mechanism by which other intermittent and variable renewable energy sources (wind, wave, solar) can play a larger role in providing electricity of commercial quality. Minimizing water consumption for producing hydropower is critical given that overuse of water for energy production may result in a shortage of water for other purposes such as irrigation, navigation or fish passage. This paper presents a dimensional analysis for finding optimal flow discharge and optimal penstock diameter when designing impulse and reaction water turbines for hydropower systems. The objective of this analysis is to provide general insights for minimizing water consumption when producing hydropower. This analysis is based on the geometric and hydraulic characteristics of the penstock, the total hydraulic head and the desired power production. As part of this analysis, various dimensionless relationships between power production, flow discharge and head losses were derived. These relationships were used to withdraw general insights on determining optimal flow discharge and optimal penstock diameter. For instance, it was found that for minimizing water consumption, the ratio of head loss to gross head should not exceed about 15%. Two examples of application are presented to illustrate the procedure for determining optimal flow discharge and optimal penstock diameter for impulse and reaction turbines.
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Optimizing rice yields while minimizing yield-scaled global warming potential.
Pittelkow, Cameron M; Adviento-Borbe, Maria A; van Kessel, Chris; Hill, James E; Linquist, Bruce A
2014-05-01
To meet growing global food demand with limited land and reduced environmental impact, agricultural greenhouse gas (GHG) emissions are increasingly evaluated with respect to crop productivity, i.e., on a yield-scaled as opposed to area basis. Here, we compiled available field data on CH4 and N2 O emissions from rice production systems to test the hypothesis that in response to fertilizer nitrogen (N) addition, yield-scaled global warming potential (GWP) will be minimized at N rates that maximize yields. Within each study, yield N surplus was calculated to estimate deficit or excess N application rates with respect to the optimal N rate (defined as the N rate at which maximum yield was achieved). Relationships between yield N surplus and GHG emissions were assessed using linear and nonlinear mixed-effects models. Results indicate that yields increased in response to increasing N surplus when moving from deficit to optimal N rates. At N rates contributing to a yield N surplus, N2 O and yield-scaled N2 O emissions increased exponentially. In contrast, CH4 emissions were not impacted by N inputs. Accordingly, yield-scaled CH4 emissions decreased with N addition. Overall, yield-scaled GWP was minimized at optimal N rates, decreasing by 21% compared to treatments without N addition. These results are unique compared to aerobic cropping systems in which N2 O emissions are the primary contributor to GWP, meaning yield-scaled GWP may not necessarily decrease for aerobic crops when yields are optimized by N fertilizer addition. Balancing gains in agricultural productivity with climate change concerns, this work supports the concept that high rice yields can be achieved with minimal yield-scaled GWP through optimal N application rates. Moreover, additional improvements in N use efficiency may further reduce yield-scaled GWP, thereby strengthening the economic and environmental sustainability of rice systems. © 2013 John Wiley & Sons Ltd.
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Application of quadratic optimization to supersonic inlet control.
NASA Technical Reports Server (NTRS)
Lehtinen, B.; Zeller, J. R.
1972-01-01
This paper describes the application of linear stochastic optimal control theory to the design of the control system for the air intake, the inlet, of a supersonic air-breathing propulsion system. The controls must maintain a stable inlet shock position in the presence of random airflow disturbances and prevent inlet unstart. Two different linear time invariant controllers are developed. One is designed to minimize a nonquadratic index, the expected frequency of inlet unstart, and the other is designed to minimize the mean square value of inlet shock motion. The quadratic equivalence principle is used to obtain a linear controller that minimizes the nonquadratic index. The two controllers are compared on the basis of unstart prevention, control effort requirements, and frequency response. It is concluded that while controls designed to minimize unstarts are desirable in that the index minimized is physically meaningful, computation time required is longer than for the minimum mean square shock position approach. The simpler minimum mean square shock position solution produced expected unstart frequency values which were not significantly larger than those of the nonquadratic solution.
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On Optimizing an Archibald Rubber-Band Heat Engine.
ERIC Educational Resources Information Center
Mullen, J. G.; And Others
1978-01-01
Discusses the criteria and procedure for optimizing the performance of Archibald rubber-band heat engines by using the appropriate choice of dimensions, minimizing frictional torque, maximizing torque and balancing the rubber band system. (GA)
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Sulcal set optimization for cortical surface registration.
Joshi, Anand A; Pantazis, Dimitrios; Li, Quanzheng; Damasio, Hanna; Shattuck, David W; Toga, Arthur W; Leahy, Richard M
2010-04-15
Flat mapping based cortical surface registration constrained by manually traced sulcal curves has been widely used for inter subject comparisons of neuroanatomical data. Even for an experienced neuroanatomist, manual sulcal tracing can be quite time consuming, with the cost increasing with the number of sulcal curves used for registration. We present a method for estimation of an optimal subset of size N(C) from N possible candidate sulcal curves that minimizes a mean squared error metric over all combinations of N(C) curves. The resulting procedure allows us to estimate a subset with a reduced number of curves to be traced as part of the registration procedure leading to optimal use of manual labeling effort for registration. To minimize the error metric we analyze the correlation structure of the errors in the sulcal curves by modeling them as a multivariate Gaussian distribution. For a given subset of sulci used as constraints in surface registration, the proposed model estimates registration error based on the correlation structure of the sulcal errors. The optimal subset of constraint curves consists of the N(C) sulci that jointly minimize the estimated error variance for the subset of unconstrained curves conditioned on the N(C) constraint curves. The optimal subsets of sulci are presented and the estimated and actual registration errors for these subsets are computed. Copyright 2009 Elsevier Inc. All rights reserved.
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Spatial frequency performance limitations of radiation dose optimization and beam positioning
NASA Astrophysics Data System (ADS)
Stewart, James M. P.; Stapleton, Shawn; Chaudary, Naz; Lindsay, Patricia E.; Jaffray, David A.
2018-06-01
The flexibility and sophistication of modern radiotherapy treatment planning and delivery methods have advanced techniques to improve the therapeutic ratio. Contemporary dose optimization and calculation algorithms facilitate radiotherapy plans which closely conform the three-dimensional dose distribution to the target, with beam shaping devices and image guided field targeting ensuring the fidelity and accuracy of treatment delivery. Ultimately, dose distribution conformity is limited by the maximum deliverable dose gradient; shallow dose gradients challenge techniques to deliver a tumoricidal radiation dose while minimizing dose to surrounding tissue. In this work, this ‘dose delivery resolution’ observation is rigorously formalized for a general dose delivery model based on the superposition of dose kernel primitives. It is proven that the spatial resolution of a delivered dose is bounded by the spatial frequency content of the underlying dose kernel, which in turn defines a lower bound in the minimization of a dose optimization objective function. In addition, it is shown that this optimization is penalized by a dose deposition strategy which enforces a constant relative phase (or constant spacing) between individual radiation beams. These results are further refined to provide a direct, analytic method to estimate the dose distribution arising from the minimization of such an optimization function. The efficacy of the overall framework is demonstrated on an image guided small animal microirradiator for a set of two-dimensional hypoxia guided dose prescriptions.
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Structural Optimization for Reliability Using Nonlinear Goal Programming
NASA Technical Reports Server (NTRS)
El-Sayed, Mohamed E.
1999-01-01
This report details the development of a reliability based multi-objective design tool for solving structural optimization problems. Based on two different optimization techniques, namely sequential unconstrained minimization and nonlinear goal programming, the developed design method has the capability to take into account the effects of variability on the proposed design through a user specified reliability design criterion. In its sequential unconstrained minimization mode, the developed design tool uses a composite objective function, in conjunction with weight ordered design objectives, in order to take into account conflicting and multiple design criteria. Multiple design criteria of interest including structural weight, load induced stress and deflection, and mechanical reliability. The nonlinear goal programming mode, on the other hand, provides for a design method that eliminates the difficulty of having to define an objective function and constraints, while at the same time has the capability of handling rank ordered design objectives or goals. For simulation purposes the design of a pressure vessel cover plate was undertaken as a test bed for the newly developed design tool. The formulation of this structural optimization problem into sequential unconstrained minimization and goal programming form is presented. The resulting optimization problem was solved using: (i) the linear extended interior penalty function method algorithm; and (ii) Powell's conjugate directions method. Both single and multi-objective numerical test cases are included demonstrating the design tool's capabilities as it applies to this design problem.
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Potassium rich rare earth (RE) borates K 3RE(BO 3) 2
NASA Astrophysics Data System (ADS)
Gao, J. H.; Li, R. K.
2008-01-01
A series of new compounds in the K 3RE(BO 3) 2 (RE = Y, Nd, Sm, Gd, Tb, Er and Lu) system were synthesized. Powder X-ray diffraction indicates that structures of the K 3RE(BO 3) 2 series can be separated into two different types with boundary between Gd and Tb. Single crystals of two representative compounds K 3Sm(BO 3) 2 and K 3Y(BO 3) 2 were obtained from a K 2O-B 2O 3 melt. The structure of K 3Y(BO 3) 2, determined from single crystal X-ray diffraction data, belongs to Pnnm space group, with lattice constants of a = 9.3377(9) Å, b = 6.7701(6) Å and c = 5.5058(4) Å. With a larger rare earth element, e.g. Sm 3+, K 3Sm(BO 3) 2 crystallizes in space group Pnma, with cell parameters of a = 9.046(3) Å, b = 7.100(2) Å and c = 11.186(3) Å. The structure of K 3Y(BO 3) 2 can be described as a three-dimensional framework formed by isolated YO 6 octahedra jointed by BO 3 triangles by sharing their apical oxygen atoms. The structure of K 3Sm(BO 3) 2 contains infinite [SmO 4BO 3] ∞ chains formed by corner sharing SmO 7 pentagonal dipyramid and BO 3 group, and those chains are interconnected by the other BO 3 groups.
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Srinivasan, Prakash; Sarmah, Ajit K
2014-09-15
We investigated the sorption potential and transport behaviour of three sulfonamides, namely, sulfamethoxazole (SMO), sulfachloropyridazine (SCP) and sulfamethazine (SM), and a conservative bromide tracer (Br(-)) in two undisturbed soil columns collected from the dairy farming regions in the North Island of New Zealand. Based on the low log Koc values obtained from the sorption study, all three sulfonamides are likely to have high mobility, making them a potential threat to surface and ground water. Soil column studies also showed that the mobility of the sulfonamides varied among soils and antibiotic type. Sulfonamides exhibited a mobility pattern similar to that of conservative Br(-) tracer. Considerable retardation was observed for the Hamilton soil, and the delayed peak arrival time (or maxima) was due to the role of sorption-related retention processes under saturated flow conditions. Residual antibiotic concentrations for SMO and SCP were detected in all soil sections including at 18 cm depth, while no resident concentration of SM was detected at any depth in the entire length of the core for both soils. The deterministic, physical equilibrium model (CXTFIT) described the peak arrival time as well as the maximum concentration of the antibiotic breakthrough curves reasonably, but showed some underestimation at the advanced stages of the leaching process. There was a significant difference in the model estimated retardation factors obtained from column study and the experimental retardation factors obtained from the conventional batch sorption experiments. Copyright © 2014 Elsevier B.V. All rights reserved.
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Inhibition of the hedgehog pathway targets the tumor-associated stroma in pancreatic cancer.
Hwang, Rosa F; Moore, Todd T; Hattersley, Maureen Mertens; Scarpitti, Meghan; Yang, Bin; Devereaux, Erik; Ramachandran, Vijaya; Arumugam, Thiruvengadam; Ji, Baoan; Logsdon, Craig D; Brown, Jeffrey L; Godin, Robert
2012-09-01
The Hedgehog (Hh) pathway has emerged as an important pathway in multiple tumor types and is thought to be dependent on a paracrine signaling mechanism. The purpose of this study was to determine the role of pancreatic cancer-associated fibroblasts (human pancreatic stellate cells, HPSCs) in Hh signaling. In addition, we evaluated the efficacy of a novel Hh antagonist, AZD8542, on tumor progression with an emphasis on the role of the stroma compartment. Expression of Hh pathway members and activation of the Hh pathway were analyzed in both HPSCs and pancreatic cancer cells. We tested the effects of Smoothened (SMO) inhibition with AZD8542 on tumor growth in vivo using an orthotopic model of pancreatic cancer containing varying amounts of stroma. HPSCs expressed high levels of SMO receptor and low levels of Hh ligands, whereas cancer cells showed the converse expression pattern. HPSC proliferation was stimulated by Sonic Hedgehog with upregulation of downstream GLI1 mRNA. These effects were abrogated by AZD8542 treatment. In an orthotopic model of pancreatic cancer, AZD8542 inhibited tumor growth only when HPSCs were present, implicating a paracrine signaling mechanism dependent on stroma. Further evidence of paracrine signaling of the Hh pathway in prostate and colon cancer models is provided, demonstrating the broader applicability of our findings. Based on the use of our novel human-derived pancreatic cancer stellate cells, our results suggest that Hh-targeted therapies primarily affect the tumor-associated stroma, rather than the epithelial compartment.
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McKenna, Rebekah; Pugh, Shawn; Thompson, Brian; Nielsen, David R
2013-12-01
(S)-Styrene oxide and (R)-1,2-phenylethanediol are chiral aromatic molecular building blocks used commonly as precursors to pharmaceuticals and other specialty chemicals. Two pathways have been engineered in Escherichia coli for their individual biosynthesis directly from glucose. The novel pathways each constitute extensions of the previously engineered styrene pathway, developed by co-expressing either styrene monooxygenase (SMO) or styrene dioxygenase (SDO) to convert styrene to (S)-styrene oxide and (R)-1,2-phenylethanediol, respectively. StyAB from Pseudomonas putida S12 was determined to be the most effective SMO. SDO activity was achieved using NahAaAbAcAd of Pseudomonas sp. NCIB 9816-4, a naphthalene dioxygenase with known broad substrate specificity. Production of phenylalanine, the precursor to both pathways, was systematically enhanced through a number of mutations, most notably via deletion of tyrA and over-expression of tktA. As a result, (R)-1,2-phenylethanediol reached titers as high as 1.23 g/L, and at 1.32 g/L (S)-styrene oxide titers already approach their toxicity limit. As with other aromatics, product toxicity was strongly correlated with a model of membrane accumulation and disruption. This study additionally demonstrates that greater flux through the styrene pathway can be achieved if its toxicity is addressed, as achieved in this case by reacting styrene to less toxic products. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Lanthanides as Catalysts: Guided Ion Beam and Theoretical Studies of Sm+ + COS.
Armentrout, P B; Cox, Richard M; Sweeny, Brendan C; Ard, Shaun G; Shuman, Nicholas S; Viggiano, Albert A
2018-01-25
Reactions of samarium cations with carbonyl sulfide are examined using a guided ion beam tandem mass spectrometer and a variable temperature selected ion flow tube apparatus. Formation of SmS + + CO is observed in both instruments with a kinetic energy and temperature dependence demonstrating a barrierless reaction occurring with an efficiency of 26 ± 9%. Formation of SmO + + CS is also observed at high kinetic energies and exhibits a threshold determined as 2.81 ± 0.32 eV, substantially higher than expected from known thermochemistry. The potential energy surfaces for these reactions along sextet and octet spin surfaces are also examined theoretically at the MP2 and CCSD(T) levels. The observed barrier for oxidation is shown to likely correspond to the energy of the crossing between surfaces corresponding to the ground state electronic configuration of Sm + ( 8 F,4f 6 6s 1 ) and an excited surface having two electrons in the valence space (excluding 4f), which are needed to form the strong SmO + bond. In contrast, the S-CO bond is activated much more readily because this crossing occurs at much lower energies. This result is attributed to the much weaker S-CO bond energy as well as the ability of sulfur to bind effectively at different angles. Although both reactions are spin-forbidden, evidence for a more efficient spin-allowed process is also observed in the SmS + + CO cross section.
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Todorovic Balint, Milena; Jelicic, Jelena; Mihaljevic, Biljana; Kostic, Jelena; Stanic, Bojana; Balint, Bela; Pejanovic, Nadja; Lucic, Bojana; Tosic, Natasa; Marjanovic, Irena; Stojiljkovic, Maja; Karan-Djurasevic, Teodora; Perisic, Ognjen; Rakocevic, Goran; Popovic, Milos; Raicevic, Sava; Bila, Jelena; Antic, Darko; Andjelic, Bosko; Pavlovic, Sonja
2016-01-01
The existence of a potential primary central nervous system lymphoma-specific genomic signature that differs from the systemic form of diffuse large B cell lymphoma (DLBCL) has been suggested, but is still controversial. We investigated 19 patients with primary DLBCL of central nervous system (DLBCL CNS) using the TruSeq Amplicon Cancer Panel (TSACP) for 48 cancer-related genes. Next generation sequencing (NGS) analyses have revealed that over 80% of potentially protein-changing mutations were located in eight genes (CTNNB1, PIK3CA, PTEN, ATM, KRAS, PTPN11, TP53 and JAK3), pointing to the potential role of these genes in lymphomagenesis. TP53 was the only gene harboring mutations in all 19 patients. In addition, the presence of mutated TP53 and ATM genes correlated with a higher total number of mutations in other analyzed genes. Furthermore, the presence of mutated ATM correlated with poorer event-free survival (EFS) (p = 0.036). The presence of the mutated SMO gene correlated with earlier disease relapse (p = 0.023), inferior event-free survival (p = 0.011) and overall survival (OS) (p = 0.017), while mutations in the PTEN gene were associated with inferior OS (p = 0.048). Our findings suggest that the TP53 and ATM genes could be involved in the molecular pathophysiology of primary DLBCL CNS, whereas mutations in the PTEN and SMO genes could affect survival regardless of the initial treatment approach. PMID:27164089
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Inhibitors of polyamine metabolism: review article.
Wallace, H M; Fraser, A V
2004-07-01
The identification of increased polyamine concentrations in a variety of diseases from cancer and psoriasis to parasitic infections has led to the hypothesis that manipulation of polyamine metabolism is a realistic target for therapeutic or preventative intervention in the treatment of certain diseases. The early development of polyamine biosynthetic single enzyme inhibitors such as alpha-difluoromethylornithine (DFMO) and methylglyoxal bis(guanylhydrazone) showed some interesting early promise as anticancer drugs, but ultimately failed in vivo. Despite this, DFMO is currently in use as an effective anti-parasitic agent and has recently also been shown to have further potential as a chemopreventative agent in colorectal cancer. The initial promise in vitro led to the development and testing of other potential inhibitors of the pathway namely the polyamine analogues. The analogues have met with greater success than the single enzyme inhibitors possibly due to their multiple targets. These include down regulation of polyamine biosynthesis through inhibition of ornithine decarboxylase and S-adenosylmethionine decarboxylase and decreased polyamine uptake. This coupled with increased activity of the catabolic enzymes, polyamine oxidase and spermidine/spermine N1-acetyltransferase, and increased polyamine export has made the analogues more effective in depleting polyamine pools. Recently, the identification of a new oxidase (PAO-h1/SMO) in polyamine catabolism and evidence of induction of both PAO and PAO-h1/SMO in response to polyamine analogue treatment, suggests the analogues may become an important part of future chemotherapeutic and/or chemopreventative regimens.
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An efficient graph theory based method to identify every minimal reaction set in a metabolic network
2014-01-01
Background Development of cells with minimal metabolic functionality is gaining importance due to their efficiency in producing chemicals and fuels. Existing computational methods to identify minimal reaction sets in metabolic networks are computationally expensive. Further, they identify only one of the several possible minimal reaction sets. Results In this paper, we propose an efficient graph theory based recursive optimization approach to identify all minimal reaction sets. Graph theoretical insights offer systematic methods to not only reduce the number of variables in math programming and increase its computational efficiency, but also provide efficient ways to find multiple optimal solutions. The efficacy of the proposed approach is demonstrated using case studies from Escherichia coli and Saccharomyces cerevisiae. In case study 1, the proposed method identified three minimal reaction sets each containing 38 reactions in Escherichia coli central metabolic network with 77 reactions. Analysis of these three minimal reaction sets revealed that one of them is more suitable for developing minimal metabolism cell compared to other two due to practically achievable internal flux distribution. In case study 2, the proposed method identified 256 minimal reaction sets from the Saccharomyces cerevisiae genome scale metabolic network with 620 reactions. The proposed method required only 4.5 hours to identify all the 256 minimal reaction sets and has shown a significant reduction (approximately 80%) in the solution time when compared to the existing methods for finding minimal reaction set. Conclusions Identification of all minimal reactions sets in metabolic networks is essential since different minimal reaction sets have different properties that effect the bioprocess development. The proposed method correctly identified all minimal reaction sets in a both the case studies. The proposed method is computationally efficient compared to other methods for finding minimal reaction sets and useful to employ with genome-scale metabolic networks. PMID:24594118
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Wang, Chang; Qi, Fei; Shi, Guangming; Wang, Xiaotian
2013-01-01
Deployment is a critical issue affecting the quality of service of camera networks. The deployment aims at adopting the least number of cameras to cover the whole scene, which may have obstacles to occlude the line of sight, with expected observation quality. This is generally formulated as a non-convex optimization problem, which is hard to solve in polynomial time. In this paper, we propose an efficient convex solution for deployment optimizing the observation quality based on a novel anisotropic sensing model of cameras, which provides a reliable measurement of the observation quality. The deployment is formulated as the selection of a subset of nodes from a redundant initial deployment with numerous cameras, which is an ℓ0 minimization problem. Then, we relax this non-convex optimization to a convex ℓ1 minimization employing the sparse representation. Therefore, the high quality deployment is efficiently obtained via convex optimization. Simulation results confirm the effectiveness of the proposed camera deployment algorithms. PMID:23989826
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Optimal vaccination strategies and rational behaviour in seasonal epidemics.
Doutor, Paulo; Rodrigues, Paula; Soares, Maria do Céu; Chalub, Fabio A C C
2016-12-01
We consider a SIRS model with time dependent transmission rate. We assume time dependent vaccination which confers the same immunity as natural infection. We study two types of vaccination strategies: (i) optimal vaccination, in the sense that it minimizes the effort of vaccination in the set of vaccination strategies for which, for any sufficiently small perturbation of the disease free state, the number of infectious individuals is monotonically decreasing; (ii) Nash-equilibria strategies where all individuals simultaneously minimize the joint risk of vaccination versus the risk of the disease. The former case corresponds to an optimal solution for mandatory vaccinations, while the second corresponds to the equilibrium to be expected if vaccination is fully voluntary. We are able to show the existence of both optimal and Nash strategies in a general setting. In general, these strategies will not be functions but Radon measures. For specific forms of the transmission rate, we provide explicit formulas for the optimal and the Nash vaccination strategies.
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Sniffer Channel Selection for Monitoring Wireless LANs
NASA Astrophysics Data System (ADS)
Song, Yuan; Chen, Xian; Kim, Yoo-Ah; Wang, Bing; Chen, Guanling
Wireless sniffers are often used to monitor APs in wireless LANs (WLANs) for network management, fault detection, traffic characterization, and optimizing deployment. It is cost effective to deploy single-radio sniffers that can monitor multiple nearby APs. However, since nearby APs often operate on orthogonal channels, a sniffer needs to switch among multiple channels to monitor its nearby APs. In this paper, we formulate and solve two optimization problems on sniffer channel selection. Both problems require that each AP be monitored by at least one sniffer. In addition, one optimization problem requires minimizing the maximum number of channels that a sniffer listens to, and the other requires minimizing the total number of channels that the sniffers listen to. We propose a novel LP-relaxation based algorithm, and two simple greedy heuristics for the above two optimization problems. Through simulation, we demonstrate that all the algorithms are effective in achieving their optimization goals, and the LP-based algorithm outperforms the greedy heuristics.
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Principles of a clean operating room environment.
Howard, James L; Hanssen, Arlen D
2007-10-01
Optimizing the operating room environment is necessary to minimize the prevalence of arthroplasty infection. Reduction of bacterial contamination in the operating room should be a primary focus of all members of the operating room team. However, in recent years, there has been a decline in the emphasis of the basic principles of antisepsis in many operating rooms. The purpose of this review is to highlight important considerations for optimizing the operating room environment. These principles should be actively promoted by orthopedic surgeons in their operating rooms as part of a comprehensive approach to minimizing arthroplasty infection.
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Optimal Black Start Resource Allocation
DOE Office of Scientific and Technical Information (OSTI.GOV)
Qiu, Feng; Wang, Jianhui; Chen, Chen
The restoration of the bulk power system after a partial or complete blackout relies on black-start (BS) resources. To prepare for system restoration, it is important to procure the right amount of BS resources at the right locations in the grid so that the total restoration time can be minimized. Achieving this goal requires that resource procurement planning takes the restoration process into account. In this study, we integrate the BS resource procurement decision with a restoration planning model and develop an optimization model that produces a minimal cost procurement plan that satisfies the restoration time requirement.
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Genetic evolutionary taboo search for optimal marker placement in infrared patient setup
NASA Astrophysics Data System (ADS)
Riboldi, M.; Baroni, G.; Spadea, M. F.; Tagaste, B.; Garibaldi, C.; Cambria, R.; Orecchia, R.; Pedotti, A.
2007-09-01
In infrared patient setup adequate selection of the external fiducial configuration is required for compensating inner target displacements (target registration error, TRE). Genetic algorithms (GA) and taboo search (TS) were applied in a newly designed approach to optimal marker placement: the genetic evolutionary taboo search (GETS) algorithm. In the GETS paradigm, multiple solutions are simultaneously tested in a stochastic evolutionary scheme, where taboo-based decision making and adaptive memory guide the optimization process. The GETS algorithm was tested on a group of ten prostate patients, to be compared to standard optimization and to randomly selected configurations. The changes in the optimal marker configuration, when TRE is minimized for OARs, were specifically examined. Optimal GETS configurations ensured a 26.5% mean decrease in the TRE value, versus 19.4% for conventional quasi-Newton optimization. Common features in GETS marker configurations were highlighted in the dataset of ten patients, even when multiple runs of the stochastic algorithm were performed. Including OARs in TRE minimization did not considerably affect the spatial distribution of GETS marker configurations. In conclusion, the GETS algorithm proved to be highly effective in solving the optimal marker placement problem. Further work is needed to embed site-specific deformation models in the optimization process.
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Optimization Methods in Sherpa
NASA Astrophysics Data System (ADS)
Siemiginowska, Aneta; Nguyen, Dan T.; Doe, Stephen M.; Refsdal, Brian L.
2009-09-01
Forward fitting is a standard technique used to model X-ray data. A statistic, usually assumed weighted chi^2 or Poisson likelihood (e.g. Cash), is minimized in the fitting process to obtain a set of the best model parameters. Astronomical models often have complex forms with many parameters that can be correlated (e.g. an absorbed power law). Minimization is not trivial in such setting, as the statistical parameter space becomes multimodal and finding the global minimum is hard. Standard minimization algorithms can be found in many libraries of scientific functions, but they are usually focused on specific functions. However, Sherpa designed as general fitting and modeling application requires very robust optimization methods that can be applied to variety of astronomical data (X-ray spectra, images, timing, optical data etc.). We developed several optimization algorithms in Sherpa targeting a wide range of minimization problems. Two local minimization methods were built: Levenberg-Marquardt algorithm was obtained from MINPACK subroutine LMDIF and modified to achieve the required robustness; and Nelder-Mead simplex method has been implemented in-house based on variations of the algorithm described in the literature. A global search Monte-Carlo method has been implemented following a differential evolution algorithm presented by Storn and Price (1997). We will present the methods in Sherpa and discuss their usage cases. We will focus on the application to Chandra data showing both 1D and 2D examples. This work is supported by NASA contract NAS8-03060 (CXC).
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Optimally Stopped Optimization
NASA Astrophysics Data System (ADS)
Vinci, Walter; Lidar, Daniel A.
2016-11-01
We combine the fields of heuristic optimization and optimal stopping. We propose a strategy for benchmarking randomized optimization algorithms that minimizes the expected total cost for obtaining a good solution with an optimal number of calls to the solver. To do so, rather than letting the objective function alone define a cost to be minimized, we introduce a further cost-per-call of the algorithm. We show that this problem can be formulated using optimal stopping theory. The expected cost is a flexible figure of merit for benchmarking probabilistic solvers that can be computed when the optimal solution is not known and that avoids the biases and arbitrariness that affect other measures. The optimal stopping formulation of benchmarking directly leads to a real-time optimal-utilization strategy for probabilistic optimizers with practical impact. We apply our formulation to benchmark simulated annealing on a class of maximum-2-satisfiability (MAX2SAT) problems. We also compare the performance of a D-Wave 2X quantum annealer to the Hamze-Freitas-Selby (HFS) solver, a specialized classical heuristic algorithm designed for low-tree-width graphs. On a set of frustrated-loop instances with planted solutions defined on up to N =1098 variables, the D-Wave device is 2 orders of magnitude faster than the HFS solver, and, modulo known caveats related to suboptimal annealing times, exhibits identical scaling with problem size.
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Optimization of a bundle divertor for FED
DOE Office of Scientific and Technical Information (OSTI.GOV)
Hively, L.M.; Rothe, K.E.; Minkoff, M.
1982-01-01
Optimal double-T bundle divertor configurations have been obtained for the Fusion Engineering Device (FED). On-axis ripple is minimized, while satisfying a series of engineering constraints. The ensuing non-linear optimization problem is solved via a sequence of quadratic programming subproblems, using the VMCON algorithm. The resulting divertor designs are substantially improved over previous configurations.
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Amber Plug-In for Protein Shop
DOE Office of Scientific and Technical Information (OSTI.GOV)
Oliva, Ricardo
2004-05-10
The Amber Plug-in for ProteinShop has two main components: an AmberEngine library to compute the protein energy models, and a module to solve the energy minimization problem using an optimization algorithm in the OPTI-+ library. Together, these components allow the visualization of the protein folding process in ProteinShop. AmberEngine is a object-oriented library to compute molecular energies based on the Amber model. The main class is called ProteinEnergy. Its main interface methods are (1) "init" to initialize internal variables needed to compute the energy. (2) "eval" to evaluate the total energy given a vector of coordinates. Additional methods allow themore » user to evaluate the individual components of the energy model (bond, angle, dihedral, non-bonded-1-4, and non-bonded energies) and to obtain the energy of each individual atom. The Amber Engine library source code includes examples and test routines that illustrate the use of the library in stand alone programs. The energy minimization module uses the AmberEngine library and the nonlinear optimization library OPT++. OPT++ is open source software available under the GNU Lesser General Public License. The minimization module currently makes use of the LBFGS optimization algorithm in OPT++ to perform the energy minimization. Future releases may give the user a choice of other algorithms available in OPT++.« less
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3D nonrigid registration via optimal mass transport on the GPU.
Ur Rehman, Tauseef; Haber, Eldad; Pryor, Gallagher; Melonakos, John; Tannenbaum, Allen
2009-12-01
In this paper, we present a new computationally efficient numerical scheme for the minimizing flow approach for optimal mass transport (OMT) with applications to non-rigid 3D image registration. The approach utilizes all of the gray-scale data in both images, and the optimal mapping from image A to image B is the inverse of the optimal mapping from B to A. Further, no landmarks need to be specified, and the minimizer of the distance functional involved is unique. Our implementation also employs multigrid, and parallel methodologies on a consumer graphics processing unit (GPU) for fast computation. Although computing the optimal map has been shown to be computationally expensive in the past, we show that our approach is orders of magnitude faster then previous work and is capable of finding transport maps with optimality measures (mean curl) previously unattainable by other works (which directly influences the accuracy of registration). We give results where the algorithm was used to compute non-rigid registrations of 3D synthetic data as well as intra-patient pre-operative and post-operative 3D brain MRI datasets.
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Launch Vehicle Propulsion Parameter Design Multiple Selection Criteria
NASA Technical Reports Server (NTRS)
Shelton, Joey Dewayne
2004-01-01
The optimization tool described herein addresses and emphasizes the use of computer tools to model a system and focuses on a concept development approach for a liquid hydrogen/liquid oxygen single-stage-to-orbit system, but more particularly the development of the optimized system using new techniques. This methodology uses new and innovative tools to run Monte Carlo simulations, genetic algorithm solvers, and statistical models in order to optimize a design concept. The concept launch vehicle and propulsion system were modeled and optimized to determine the best design for weight and cost by varying design and technology parameters. Uncertainty levels were applied using Monte Carlo Simulations and the model output was compared to the National Aeronautics and Space Administration Space Shuttle Main Engine. Several key conclusions are summarized here for the model results. First, the Gross Liftoff Weight and Dry Weight were 67% higher for the design case for minimization of Design, Development, Test and Evaluation cost when compared to the weights determined by the minimization of Gross Liftoff Weight case. In turn, the Design, Development, Test and Evaluation cost was 53% higher for optimized Gross Liftoff Weight case when compared to the cost determined by case for minimization of Design, Development, Test and Evaluation cost. Therefore, a 53% increase in Design, Development, Test and Evaluation cost results in a 67% reduction in Gross Liftoff Weight. Secondly, the tool outputs define the sensitivity of propulsion parameters, technology and cost factors and how these parameters differ when cost and weight are optimized separately. A key finding was that for a Space Shuttle Main Engine thrust level the oxidizer/fuel ratio of 6.6 resulted in the lowest Gross Liftoff Weight rather than at 5.2 for the maximum specific impulse, demonstrating the relationships between specific impulse, engine weight, tank volume and tank weight. Lastly, the optimum chamber pressure for Gross Liftoff Weight minimization was 2713 pounds per square inch as compared to 3162 for the Design, Development, Test and Evaluation cost optimization case. This chamber pressure range is close to 3000 pounds per square inch for the Space Shuttle Main Engine.
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Barca, E; Castrignanò, A; Buttafuoco, G; De Benedetto, D; Passarella, G
2015-07-01
Soil survey is generally time-consuming, labor-intensive, and costly. Optimization of sampling scheme allows one to reduce the number of sampling points without decreasing or even increasing the accuracy of investigated attribute. Maps of bulk soil electrical conductivity (EC a ) recorded with electromagnetic induction (EMI) sensors could be effectively used to direct soil sampling design for assessing spatial variability of soil moisture. A protocol, using a field-scale bulk EC a survey, has been applied in an agricultural field in Apulia region (southeastern Italy). Spatial simulated annealing was used as a method to optimize spatial soil sampling scheme taking into account sampling constraints, field boundaries, and preliminary observations. Three optimization criteria were used. the first criterion (minimization of mean of the shortest distances, MMSD) optimizes the spreading of the point observations over the entire field by minimizing the expectation of the distance between an arbitrarily chosen point and its nearest observation; the second criterion (minimization of weighted mean of the shortest distances, MWMSD) is a weighted version of the MMSD, which uses the digital gradient of the grid EC a data as weighting function; and the third criterion (mean of average ordinary kriging variance, MAOKV) minimizes mean kriging estimation variance of the target variable. The last criterion utilizes the variogram model of soil water content estimated in a previous trial. The procedures, or a combination of them, were tested and compared in a real case. Simulated annealing was implemented by the software MSANOS able to define or redesign any sampling scheme by increasing or decreasing the original sampling locations. The output consists of the computed sampling scheme, the convergence time, and the cooling law, which can be an invaluable support to the process of sampling design. The proposed approach has found the optimal solution in a reasonable computation time. The use of bulk EC a gradient as an exhaustive variable, known at any node of an interpolation grid, has allowed the optimization of the sampling scheme, distinguishing among areas with different priority levels.
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Flat-plate photovoltaic array design optimization
NASA Technical Reports Server (NTRS)
Ross, R. G., Jr.
1980-01-01
An analysis is presented which integrates the results of specific studies in the areas of photovoltaic structural design optimization, optimization of array series/parallel circuit design, thermal design optimization, and optimization of environmental protection features. The analysis is based on minimizing the total photovoltaic system life-cycle energy cost including repair and replacement of failed cells and modules. This approach is shown to be a useful technique for array optimization, particularly when time-dependent parameters such as array degradation and maintenance are involved.
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Optimal design of multichannel equalizers for the structural similarity index.
Chai, Li; Sheng, Yuxia
2014-12-01
The optimization of multichannel equalizers is studied for the structural similarity (SSIM) criteria. The closed-form formula is provided for the optimal equalizer when the mean of the source is zero. The formula shows that the equalizer with maximal SSIM index is equal to the one with minimal mean square error (MSE) multiplied by a positive real number, which is shown to be equal to the inverse of the achieved SSIM index. The relation of the maximal SSIM index to the minimal MSE is also established for given blurring filters and fixed length equalizers. An algorithm is also presented to compute the suboptimal equalizer for the general sources. Various numerical examples are given to demonstrate the effectiveness of the results.
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Metabolic flux estimation using particle swarm optimization with penalty function.
Long, Hai-Xia; Xu, Wen-Bo; Sun, Jun
2009-01-01
Metabolic flux estimation through 13C trace experiment is crucial for quantifying the intracellular metabolic fluxes. In fact, it corresponds to a constrained optimization problem that minimizes a weighted distance between measured and simulated results. In this paper, we propose particle swarm optimization (PSO) with penalty function to solve 13C-based metabolic flux estimation problem. The stoichiometric constraints are transformed to an unconstrained one, by penalizing the constraints and building a single objective function, which in turn is minimized using PSO algorithm for flux quantification. The proposed algorithm is applied to estimate the central metabolic fluxes of Corynebacterium glutamicum. From simulation results, it is shown that the proposed algorithm has superior performance and fast convergence ability when compared to other existing algorithms.
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Optimizing Medical Kits for Space Flight
NASA Technical Reports Server (NTRS)
Minard, Charles G.; FreiredeCarvalho, Mary H.; Iyengar, M. Sriram
2010-01-01
The Integrated Medical Model (IMM) uses Monte Carlo methodologies to predict the occurrence of medical events, their mitigation, and the resources required during space flight. The model includes two modules that utilize output from a single model simulation to identify an optimized medical kit for a specified mission scenario. This poster describes two flexible optimization routines built into SAS 9.1. The first routine utilizes a systematic process of elimination to maximize (or minimize) outcomes subject to attribute constraints. The second routine uses a search and mutate approach to minimize medical kit attributes given a set of outcome constraints. There are currently 273 unique resources identified that are used to treat at least one of 83 medical conditions currently in the model.
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Optimal bounds and extremal trajectories for time averages in nonlinear dynamical systems
NASA Astrophysics Data System (ADS)
Tobasco, Ian; Goluskin, David; Doering, Charles R.
2018-02-01
For any quantity of interest in a system governed by ordinary differential equations, it is natural to seek the largest (or smallest) long-time average among solution trajectories, as well as the extremal trajectories themselves. Upper bounds on time averages can be proved a priori using auxiliary functions, the optimal choice of which is a convex optimization problem. We prove that the problems of finding maximal trajectories and minimal auxiliary functions are strongly dual. Thus, auxiliary functions provide arbitrarily sharp upper bounds on time averages. Moreover, any nearly minimal auxiliary function provides phase space volumes in which all nearly maximal trajectories are guaranteed to lie. For polynomial equations, auxiliary functions can be constructed by semidefinite programming, which we illustrate using the Lorenz system.
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Modeling of tool path for the CNC sheet cutting machines
NASA Astrophysics Data System (ADS)
Petunin, Aleksandr A.
2015-11-01
In the paper the problem of tool path optimization for CNC (Computer Numerical Control) cutting machines is considered. The classification of the cutting techniques is offered. We also propose a new classification of toll path problems. The tasks of cost minimization and time minimization for standard cutting technique (Continuous Cutting Problem, CCP) and for one of non-standard cutting techniques (Segment Continuous Cutting Problem, SCCP) are formalized. We show that the optimization tasks can be interpreted as discrete optimization problem (generalized travel salesman problem with additional constraints, GTSP). Formalization of some constraints for these tasks is described. For the solution GTSP we offer to use mathematical model of Prof. Chentsov based on concept of a megalopolis and dynamic programming.
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Anzalone, Anthony J; Blueitt, Damond; Case, Tami; McGuffin, Tiffany; Pollard, Kalyssa; Garrison, J Craig; Jones, Margaret T; Pavur, Robert; Turner, Stephanie; Oliver, Jonathan M
2017-02-01
Vestibular and ocular motor impairments are routinely reported in patients with sports-related concussion (SRC) and may result in delayed return to play (RTP). The Vestibular/Ocular Motor Screening (VOMS) assessment has been shown to be consistent and sensitive in identifying concussion when used as part of a comprehensive examination. To what extent these impairments or symptoms are associated with length of recovery is unknown. To examine whether symptom provocation or clinical abnormality in specific domains of the VOMS results in protracted recovery (time from SRC to commencement of RTP protocol). Cohort study (prognosis); Level of evidence, 2. A retrospective chart review was conducted of 167 patients (69 girls, 98 boys; mean ± SD age, 15 ± 2 years [range, 11-19 years]) presenting with SRC in 2014. During the initial visit, VOMS was performed in which symptom provocation or clinical abnormality (eg, unsmooth eye movements) was documented by use of a dichotomous scale (0 = not present, 1 = present). The VOMS used in this clinic consisted of smooth pursuits (SMO_PUR), horizontal and vertical saccades (HOR_SAC and VER_SAC), horizontal and vertical vestibular ocular reflex (HOR_VOR and VER_VOR), near point of convergence (NPC), and accommodation (ACCOM). Domains were also categorized into ocular motor (SMO_PUR, HOR_SAC, VER_SAC, NPC, ACCOM) and vestibular (HOR_VOR, VER_VOR). Cox proportional hazard models were used to explore the relationship between the domains and recovery. Alpha was set at P ≤ .05. Symptom provocation and/or clinical abnormality in all domains except NPC ( P = .107) and ACCOM ( P = .234) delayed recovery (domain, hazard ratio [95% CI]: SMO_PUR, 0.65 [0.47-0.90], P = .009; HOR_SAC, 0.68 [0.50-0.94], P = .018; VER_SAC, 0.55 [0.40-0.75], P < .001; HOR_VOR, 0.68 [0.49-0.94], P = .018; VER_VOR, 0.60 [0.44-0.83], P = .002). The lowest crude hazard ratio was for ocular motor category (0.45 [0.32-0.63], P < .001). These data suggest that symptom provocation/clinical abnormality associated with all domains except NPC and ACCOM can delay recovery after SRC in youth and adolescents. Thus, the VOMS not only may augment current diagnostic tools but also may serve as a predictor of recovery time in patients with SRC. The findings of this study may lead to more effective prognosis of concussion in youth and adolescents.
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NASA Astrophysics Data System (ADS)
Zarate-Del Valle, P. F.; Gomez-Hermosillo, C. M.; Venegas-Garcia, D. J.
2007-12-01
Santa Maria del Oro Lake ( SMO) (21.37° N, 104.57° W; 750 m a.s.l.) is a quaternary crater-lake located at western Mexico in the natural border between two geological provinces: the plio-quaternary Trans-Mexican Volcanic Belt and the oligo-miocenic silicic volcanic province Sierra Madre Occidental. SMO, a tropical freshwater lake, is a warm-monomictic lake having a diameter of ca. 2 km and a mean depth at the depocenter of ca. 60 m, where three benthos cores were recovered. Contents of POP' s, total inorganic carbon (TIC), total organic carbon (TOC) and heavy metals were analyzed. Geochemistry and mineralogy also were studied in shallow sediments which corresponded to the decade of 50-60's, otherwise the beginning of industrial development of central Mexico; which is considered the possible source of emission of POP' s and heavy metals. Dioxin, furan, plaguicides and PCB' s contents were analyzed by a GC-MS applying USEPA methods. In the first 40 cm (n= 20) of the sedimentary column ( SC) the absence of POP' s was evidenced, applying a method detection limit ( MDL) of 5 μ g/ml for dioxin, furan and PCB' s. For plaguicides like chlordane and toxaphene the MDL was 0.5 μ g/ml and for plaguicides like DDT, aldrin, endrin, dieldrin, heptachlore and mirex the MDL was 5 μ g/ml. The MDL for HCB was 1 μ g/ml. The average (n= 30) for TIC, TOC and total carbon (TC) for the first 40 cm of the SC is as follows: TIC 2.4 %, TOC 3.7 % and TC 6.12 %. The average (n= 20) content (in ppm) of heavy metals for the first 20 cm of the SC is as follows: As 5.97, Cr 27.54, Cu 16.31, Ni 12.29, Pb 21.35 and Zn 82.46. These contents are roughly similar to the clarke of these metals in volcanic rocks. After the criteria of severe effect level ( SEL) of heavy metal in sediments, the content of these metals is below SEL levels. These results permit us to conclude that the sediments of SMO can be considered in unaffected state with respect to antropogenic contamination like POP' s and heavy metals. Consequently, Santa Maria del Oro Lake can be considered as a pristine reference in paleo-ecological and environmental investigations in western Mexico.
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$L^1$ penalization of volumetric dose objectives in optimal control of PDEs
Barnard, Richard C.; Clason, Christian
2017-02-11
This work is concerned with a class of PDE-constrained optimization problems that are motivated by an application in radiotherapy treatment planning. Here the primary design objective is to minimize the volume where a functional of the state violates a prescribed level, but prescribing these levels in the form of pointwise state constraints leads to infeasible problems. We therefore propose an alternative approach based on L 1 penalization of the violation that is also applicable when state constraints are infeasible. We establish well-posedness of the corresponding optimal control problem, derive first-order optimality conditions, discuss convergence of minimizers as the penalty parametermore » tends to infinity, and present a semismooth Newton method for their efficient numerical solution. Finally, the performance of this method for a model problem is illustrated and contrasted with an alternative approach based on (regularized) state constraints.« less
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Investigation of another approach in topology optimization
NASA Astrophysics Data System (ADS)
Krotkikh, A. A.; Maximov, P. V.
2018-05-01
The paper presents investigation of another approach in topology optimization. The authors realized the method of topology optimization with using ideas of the SIMP method which was created by Martin P. Bends0e. There are many ways in objective function formulation of topology optimization methods. In terms of elasticity theory, the objective function of the SIMP method is a compliance of an object which should be minimized. The main idea of this paper was avoiding the filtering procedure in the SIMP method. Reformulation of the statement of the problem in terms of function minimization allows us to solve this by big variety of methods. The authors decided to use the interior point method which was realized in Wolfram Mathematica. This way can generate side effects which should be investigated for preventing their appearing in future. Results comparison of the SIMP method and the suggested method are presented in paper and analyzed.
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The application of nonlinear programming and collocation to optimal aeroassisted orbital transfers
NASA Astrophysics Data System (ADS)
Shi, Y. Y.; Nelson, R. L.; Young, D. H.; Gill, P. E.; Murray, W.; Saunders, M. A.
1992-01-01
Sequential quadratic programming (SQP) and collocation of the differential equations of motion were applied to optimal aeroassisted orbital transfers. The Optimal Trajectory by Implicit Simulation (OTIS) computer program codes with updated nonlinear programming code (NZSOL) were used as a testbed for the SQP nonlinear programming (NLP) algorithms. The state-of-the-art sparse SQP method is considered to be effective for solving large problems with a sparse matrix. Sparse optimizers are characterized in terms of memory requirements and computational efficiency. For the OTIS problems, less than 10 percent of the Jacobian matrix elements are nonzero. The SQP method encompasses two phases: finding an initial feasible point by minimizing the sum of infeasibilities and minimizing the quadratic objective function within the feasible region. The orbital transfer problem under consideration involves the transfer from a high energy orbit to a low energy orbit.
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An optimal open/closed-loop control method with application to a pre-stressed thin duralumin plate
NASA Astrophysics Data System (ADS)
Nadimpalli, Sruthi Raju
The excessive vibrations of a pre-stressed duralumin plate, suppressed by a combination of open-loop and closed-loop controls, also known as open/closed-loop control, is studied in this thesis. The two primary steps involved in this process are: Step (I) with an assumption that the closed-loop control law is proportional, obtain the optimal open-loop control by direct minimization of the performance measure consisting of energy at terminal time and a penalty on open-loop control force via calculus of variations. If the performance measure also involves a penalty on closed-loop control effort then a Fourier based method is utilized. Step (II) the energy at terminal time is minimized numerically to obtain optimal values of feedback gains. The optimal closed-loop control gains obtained are used to describe the displacement and the velocity of open-loop, closed-loop and open/closed-loop controlled duralumin plate.
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Optimized Projection Matrix for Compressive Sensing
NASA Astrophysics Data System (ADS)
Xu, Jianping; Pi, Yiming; Cao, Zongjie
2010-12-01
Compressive sensing (CS) is mainly concerned with low-coherence pairs, since the number of samples needed to recover the signal is proportional to the mutual coherence between projection matrix and sparsifying matrix. Until now, papers on CS always assume the projection matrix to be a random matrix. In this paper, aiming at minimizing the mutual coherence, a method is proposed to optimize the projection matrix. This method is based on equiangular tight frame (ETF) design because an ETF has minimum coherence. It is impossible to solve the problem exactly because of the complexity. Therefore, an alternating minimization type method is used to find a feasible solution. The optimally designed projection matrix can further reduce the necessary number of samples for recovery or improve the recovery accuracy. The proposed method demonstrates better performance than conventional optimization methods, which brings benefits to both basis pursuit and orthogonal matching pursuit.
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Optimal control of a rabies epidemic model with a birth pulse.
Clayton, Tim; Duke-Sylvester, Scott; Gross, Louis J; Lenhart, Suzanne; Real, Leslie A
2010-01-01
A system of ordinary differential equations describes the population dynamics of a rabies epidemic in raccoons. The model accounts for the dynamics of a vaccine, including loss of vaccine due to animal consumption and loss from factors other than racoon uptake. A control method to reduce the spread of disease is introduced through temporal distribution of vaccine packets. This work incorporates the effect of the seasonal birth pulse in the racoon population and the attendant increase in new-borns which are susceptible to the diseases, analysing the impact of the timing and length of this pulse on the optimal distribution of vaccine packets. The optimization criterion is to minimize the number of infected raccoons while minimizing the cost of distributing the vaccine. Using an optimal control setting, numerical results illustrate strategies for distributing the vaccine depending on the timing of the infection outbreak with respect to the birth pulse.
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Optimal Control of a Rabies Epidemic Model with a Birth Pulse
Clayton, Tim; Duke-Sylvester, Scott; Gross, Louis J.; Lenhart, Suzanne; Real, Leslie A.
2011-01-01
A system of ordinary differential equations describes the populuation dynamics of a rabies epidemic in raccoons. The model accounts for the dynamics of vaccine, including loss of vaccine due to animal consumption and loss from factors other than racoon uptake. A control method to reduce the spread of disease is introduced through temporal distribution of vaccine packets. This work incorporates the effect of the seasonal birth pulse in the racoon population and the attendant increase in new-borns which are susceptible to the diseases, analysing the impact of the timing and length of this pulse on the optimal distribution of vaccine packets. The optimization criterion is to minimize the number of infected raccoons while minimizing the cost of distributing the vaccine. Using an optimal control setting, numerical results illustrate strategies for distributing vaccine depending on the timing of the infection outbreak with respect to the birth pulse. PMID:21423822
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Zilinskas, Julius; Lančinskas, Algirdas; Guarracino, Mario Rosario
2014-01-01
In this paper we propose some mathematical models to plan a Next Generation Sequencing experiment to detect rare mutations in pools of patients. A mathematical optimization problem is formulated for optimal pooling, with respect to minimization of the experiment cost. Then, two different strategies to replicate patients in pools are proposed, which have the advantage to decrease the overall costs. Finally, a multi-objective optimization formulation is proposed, where the trade-off between the probability to detect a mutation and overall costs is taken into account. The proposed solutions are devised in pursuance of the following advantages: (i) the solution guarantees mutations are detectable in the experimental setting, and (ii) the cost of the NGS experiment and its biological validation using Sanger sequencing is minimized. Simulations show replicating pools can decrease overall experimental cost, thus making pooling an interesting option.
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Optimization of simultaneous tritium–radiocarbon internal gas proportional counting
DOE Office of Scientific and Technical Information (OSTI.GOV)
Bonicalzi, R. M.; Aalseth, C. E.; Day, A. R.
Specific environmental applications can benefit from dual tritium and radiocarbon measurements in a single compound. Assuming typical environmental levels, it is often the low tritium activity relative to the higher radiocarbon activity that limits the dual measurement. In this paper, we explore the parameter space for a combined tritium and radiocarbon measurement using a methane sample mixed with an argon fill gas in low-background proportional counters of a specific design. We present an optimized methane percentage, detector fill pressure, and analysis energy windows to maximize measurement sensitivity while minimizing count time. The final optimized method uses a 9-atm fill ofmore » P35 (35% methane, 65% argon), and a tritium analysis window from 1.5 to 10.3 keV, which stops short of the tritium beta decay endpoint energy of 18.6 keV. This method optimizes tritium counting efficiency while minimizing radiocarbon beta decay interference.« less
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Phase Transition in Protocols Minimizing Work Fluctuations
NASA Astrophysics Data System (ADS)
Solon, Alexandre P.; Horowitz, Jordan M.
2018-05-01
For two canonical examples of driven mesoscopic systems—a harmonically trapped Brownian particle and a quantum dot—we numerically determine the finite-time protocols that optimize the compromise between the standard deviation and the mean of the dissipated work. In the case of the oscillator, we observe a collection of protocols that smoothly trade off between average work and its fluctuations. However, for the quantum dot, we find that as we shift the weight of our optimization objective from average work to work standard deviation, there is an analog of a first-order phase transition in protocol space: two distinct protocols exchange global optimality with mixed protocols akin to phase coexistence. As a result, the two types of protocols possess qualitatively different properties and remain distinct even in the infinite duration limit: optimal-work-fluctuation protocols never coalesce with the minimal-work protocols, which therefore never become quasistatic.
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2014-01-01
Berth allocation is the forefront operation performed when ships arrive at a port and is a critical task in container port optimization. Minimizing the time ships spend at berths constitutes an important objective of berth allocation problems. This study focuses on the discrete dynamic berth allocation problem (discrete DBAP), which aims to minimize total service time, and proposes an iterated greedy (IG) algorithm to solve it. The proposed IG algorithm is tested on three benchmark problem sets. Experimental results show that the proposed IG algorithm can obtain optimal solutions for all test instances of the first and second problem sets and outperforms the best-known solutions for 35 out of 90 test instances of the third problem set. PMID:25295295
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Optimal mistuning for enhanced aeroelastic stability of transonic fans
NASA Technical Reports Server (NTRS)
Hall, K. C.; Crawley, E. F.
1983-01-01
An inverse design procedure was developed for the design of a mistuned rotor. The design requirements are that the stability margin of the eigenvalues of the aeroelastic system be greater than or equal to some minimum stability margin, and that the mass added to each blade be positive. The objective was to achieve these requirements with a minimal amount of mistuning. Hence, the problem was posed as a constrained optimization problem. The constrained minimization problem was solved by the technique of mathematical programming via augmented Lagrangians. The unconstrained minimization phase of this technique was solved by the variable metric method. The bladed disk was modelled as being composed of a rigid disk mounted on a rigid shaft. Each of the blades were modelled with a single tosional degree of freedom.
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NASA Astrophysics Data System (ADS)
Kenway, Gaetan K. W.
This thesis presents new tools and techniques developed to address the challenging problem of high-fidelity aerostructural optimization with respect to large numbers of design variables. A new mesh-movement scheme is developed that is both computationally efficient and sufficiently robust to accommodate large geometric design changes and aerostructural deformations. A fully coupled Newton-Krylov method is presented that accelerates the convergence of aerostructural systems and provides a 20% performance improvement over the traditional nonlinear block Gauss-Seidel approach and can handle more exible structures. A coupled adjoint method is used that efficiently computes derivatives for a gradient-based optimization algorithm. The implementation uses only machine accurate derivative techniques and is verified to yield fully consistent derivatives by comparing against the complex step method. The fully-coupled large-scale coupled adjoint solution method is shown to have 30% better performance than the segregated approach. The parallel scalability of the coupled adjoint technique is demonstrated on an Euler Computational Fluid Dynamics (CFD) model with more than 80 million state variables coupled to a detailed structural finite-element model of the wing with more than 1 million degrees of freedom. Multi-point high-fidelity aerostructural optimizations of a long-range wide-body, transonic transport aircraft configuration are performed using the developed techniques. The aerostructural analysis employs Euler CFD with a 2 million cell mesh and a structural finite element model with 300 000 DOF. Two design optimization problems are solved: one where takeoff gross weight is minimized, and another where fuel burn is minimized. Each optimization uses a multi-point formulation with 5 cruise conditions and 2 maneuver conditions. The optimization problems have 476 design variables are optimal results are obtained within 36 hours of wall time using 435 processors. The TOGW minimization results in a 4.2% reduction in TOGW with a 6.6% fuel burn reduction, while the fuel burn optimization resulted in a 11.2% fuel burn reduction with no change to the takeoff gross weight.
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Optimal synthesis and design of the number of cycles in the leaching process for surimi production.
Reinheimer, M Agustina; Scenna, Nicolás J; Mussati, Sergio F
2016-12-01
Water consumption required during the leaching stage in the surimi manufacturing process strongly depends on the design and the number and size of stages connected in series for the soluble protein extraction target, and it is considered as the main contributor to the operating costs. Therefore, the optimal synthesis and design of the leaching stage is essential to minimize the total annual cost. In this study, a mathematical optimization model for the optimal design of the leaching operation is presented. Precisely, a detailed Mixed Integer Nonlinear Programming (MINLP) model including operating and geometric constraints was developed based on our previous optimization model (NLP model). Aspects about quality, water consumption and main operating parameters were considered. The minimization of total annual costs, which considered a trade-off between investment and operating costs, led to an optimal solution with lesser number of stages (2 instead of 3 stages) and higher volumes of the leaching tanks comparing with previous results. An analysis was performed in order to investigate how the optimal solution was influenced by the variations of the unitary cost of fresh water, waste treatment and capital investment.
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Economic and environmental optimization of waste treatment
DOE Office of Scientific and Technical Information (OSTI.GOV)
Münster, M.; Ravn, H.; Hedegaard, K.
2015-04-15
Highlights: • Optimizing waste treatment by incorporating LCA methodology. • Applying different objectives (minimizing costs or GHG emissions). • Prioritizing multiple objectives given different weights. • Optimum depends on objective and assumed displaced electricity production. - Abstract: This article presents the new systems engineering optimization model, OptiWaste, which incorporates a life cycle assessment (LCA) methodology and captures important characteristics of waste management systems. As part of the optimization, the model identifies the most attractive waste management options. The model renders it possible to apply different optimization objectives such as minimizing costs or greenhouse gas emissions or to prioritize several objectivesmore » given different weights. A simple illustrative case is analysed, covering alternative treatments of one tonne of residual household waste: incineration of the full amount or sorting out organic waste for biogas production for either combined heat and power generation or as fuel in vehicles. The case study illustrates that the optimal solution depends on the objective and assumptions regarding the background system – illustrated with different assumptions regarding displaced electricity production. The article shows that it is feasible to combine LCA methodology with optimization. Furthermore, it highlights the need for including the integrated waste and energy system into the model.« less