Directory of Open Access Journals (Sweden)
Vipan Kumar Sohpal
2011-12-01
Full Text Available Protein sequence alignment has become an informative tool in modern molecular biology research. A number of substitution matrices have been readily available for sequence alignments, but it is challenging task to compute optimal matrices for alignment accuracy. Here, we used the parameter optimization procedure to select the optimal Q of substitution matrices for major viral capsid protein of human herpes simplex virus. Results predict that Blosum matrix is most accurate on alignment benchmarks, and Blosum 60 provides the optimal Q in all substitution matrices. PAM 200 matrices results slightly below than Blosum 60, while VTML matrices are intermediate of PAM and VT matrices under dynamic programming.
Empirical codon substitution matrix
Directory of Open Access Journals (Sweden)
Gonnet Gaston H
2005-06-01
Full Text Available Abstract Background Codon substitution probabilities are used in many types of molecular evolution studies such as determining Ka/Ks ratios, creating ancestral DNA sequences or aligning coding DNA. Until the recent dramatic increase in genomic data enabled construction of empirical matrices, researchers relied on parameterized models of codon evolution. Here we present the first empirical codon substitution matrix entirely built from alignments of coding sequences from vertebrate DNA and thus provide an alternative to parameterized models of codon evolution. Results A set of 17,502 alignments of orthologous sequences from five vertebrate genomes yielded 8.3 million aligned codons from which the number of substitutions between codons were counted. From this data, both a probability matrix and a matrix of similarity scores were computed. They are 64 × 64 matrices describing the substitutions between all codons. Substitutions from sense codons to stop codons are not considered, resulting in block diagonal matrices consisting of 61 × 61 entries for the sense codons and 3 × 3 entries for the stop codons. Conclusion The amount of genomic data currently available allowed for the construction of an empirical codon substitution matrix. However, more sequence data is still needed to construct matrices from different subsets of DNA, specific to kingdoms, evolutionary distance or different amount of synonymous change. Codon mutation matrices have advantages for alignments up to medium evolutionary distances and for usages that require DNA such as ancestral reconstruction of DNA sequences and the calculation of Ka/Ks ratios.
Directory of Open Access Journals (Sweden)
Leonardo Leiderman
1992-03-01
Full Text Available Simulating an Optimizing Model of Currency Substitution This paper reports simulations based on the parameter estimates of an intertemporal model of currency substitution under nonexpected utility obtained by Bufman and Leiderman (1991. Here we first study the quantitative impact of changes in the degree of dollarization and in the elasticity of currency substitution on government seigniorage. Then, when examine whether the model can account for the comovement of consumption growth and assets' returnr after the 1985 stabilization program, and in particular for the consumption boom of 1986-87. The results are generally encouraging for future applications of optimizing models of currencysubstitution to policy and practical issues.
Optimized Projection Matrix for Compressive Sensing
Directory of Open Access Journals (Sweden)
Jianping Xu
2010-01-01
Full Text Available 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.
An Optimized Sparse Approximate Matrix Multiply
Bock, Nicolas
2012-01-01
We present an optimized single-precision implementation of the Sparse Approximate Matrix Multiply (\\SpAMM{}) [M. Challacombe and N. Bock, arXiv {\\bf 1011.3534} (2010)], a fast algorithm for matrix-matrix multiplication for matrices with decay that achieves an $\\mathcal{O} (n \\ln n)$ computational complexity with respect to matrix dimension $n$. We find that the max norm of the error matrix achieved with a \\SpAMM{} tolerance of below $2 \\times 10^{-8}$ is lower than that of the single-precision {\\tt SGEMM} for quantum chemical test matrices, while outperforming {\\tt SGEMM} with a cross-over already for small matrices ($n \\sim 1000$). Relative to naive implementations of \\SpAMM{} using optimized versions of {\\tt SGEMM}, such as those found in Intel's Math Kernel Library ({\\tt MKL}) or AMD's Core Math Library ({\\tt ACML}), our optimized version is found to be significantly faster. Detailed performance comparisons are made with for quantum chemical matrices of RHF/STO-2G and RHF/6-31G${}^{**}$ water clusters.
Aligning protein sequence and analysing substitution pattern using a class-specific matrix
Indian Academy of Sciences (India)
Hai Song Xu; Wen Ke Ren; Xiao Hui Liu; Xiao Qin Li
2010-06-01
Aligning protein sequences using a score matrix has became a routine but valuable method in modern biological research. However, alignment in the ‘twilight zone’ remains an open issue. It is feasible and necessary to construct a new score matrix as more protein structures are resolved. Three structural class-specific score matrices (all-alpha, all-beta and alpha/beta) were constructed based on the structure alignment of low identity proteins of the corresponding structural classes. The class-specific score matrices were significantly better than a structure-derived matrix (HSDM) and three other generalized matrices (BLOSUM30, BLOSUM60 and Gonnet250) in alignment performance tests. The optimized gap penalties presented here also promote alignment performance. The results indicate that different protein classes have distinct amino acid substitution patterns, and an amino acid score matrix should be constructed based on different structural classes. The class-specific score matrices could also be used in profile construction to improve homology detection.
Optimizing strassen matrix multiply on GPUs
ul Hasan Khan, Ayaz
2015-06-01
© 2015 IEEE. Many core systems are basically designed for applications having large data parallelism. Strassen Matrix Multiply (MM) can be formulated as a depth first (DFS) traversal of a recursion tree where all cores work in parallel on computing each of the NxN sub-matrices that reduces storage at the detriment of large data motion to gather and aggregate the results. We propose Strassen and Winograd algorithms (S-MM and W-MM) based on three optimizations: a set of basic algebra functions to reduce overhead, invoking efficient library (CUBLAS 5.5), and parameter-tuning of parametric kernel to improve resource occupancy. On GPUs, W-MM and S-MM with one recursion level outperform CUBLAS 5.5 Library with up to twice as faster for large arrays satisfying N>=2048 and N>=3072, respectively. Compared to NVIDIA SDK library, S-MM and W-MM achieved a speedup between 20x to 80x for the above arrays. The proposed approach can be used to enhance the performance of CUBLAS and MKL libraries.
The Substitution Secant/Finite Difference Method for Large Scale Sparse Unconstrained Optimization
Institute of Scientific and Technical Information of China (English)
Hong-wei Zhang; Jun-xiang Li
2005-01-01
This paper studies a substitution secant/finite difference (SSFD) method for solving large scale sparse unconstrained optimization problems. This method is a combination of a secant method and a finite difference method, which depends on a consistent partition of the columns of the lower triangular part of the Hessian matrix. A q-superlinear convergence result and an r-convergence rate estimate show that this method has good local convergence properties. The numerical results show that this method may be competitive with some currently used algorithms.
Braziulis, Erik; Diezi, Mirco; Biedermann, Thomas; Pontiggia, Luca; Schmucki, Marlene; Hartmann-Fritsch, Fabienne; Luginbühl, Joachim; Schiestl, Clemens; Meuli, Martin; Reichmann, Ernst
2012-06-01
Tissue engineering of clinically applicable dermo-epidermal skin substitutes is crucially dependent on the three-dimensional extracellular matrix, supporting the biological function of epidermal and dermal cells. This matrix essentially determines the mechanical stability of these substitutes to allow for safe and convenient surgical handling. Collagen type I hydrogels yield excellent biological functionality, but their mechanical weakness and their tendency to contract and degrade does not allow producing clinically applicable transplants of larger sizes. We show here that plastically compressed collagen type I hydrogels can be produced in clinically relevant sizes (7×7 cm), and can be safely and conveniently handled by the surgeon. Most importantly, these dermo-epidermal skin substitutes mature into a near normal skin that can successfully reconstitute full-thickness skin defects in an animal model.
Toeplitz block circulant matrix optimized with particle swarm optimization for compressive imaging
Tao, Huifeng; Yin, Songfeng; Tang, Cong
2016-10-01
Compressive imaging is an imaging way based on the compressive sensing theory, which could achieve to capture the high resolution image through a small set of measurements. As the core of the compressive imaging, the design of the measurement matrix is sufficient to ensure that the image can be recovered from the measurements. Due to the fast computing capacity and the characteristic of easy hardware implementation, The Toeplitz block circulant matrix is proposed to realize the encoded samples. The measurement matrix is usually optimized for improving the image reconstruction quality. However, the existing optimization methods can destroy the matrix structure easily when applied to the Toeplitz block circulant matrix optimization process, and the deterministic iterative processes of them are inflexible, because of requiring the task optimized to need to satisfy some certain mathematical property. To overcome this problem, a novel method of optimizing the Toeplitz block circulant matrix based on the particle swarm optimization intelligent algorithm is proposed in this paper. The objective function is established by the way of approaching the target matrix that is the Gram matrix truncated by the Welch threshold. The optimized object is the vector composed by the free entries instead of the Gram matrix. The experimental results indicate that the Toeplitz block circulant measurement matrix can be optimized while preserving the matrix structure by our method, and result in the reconstruction quality improvement.
Numerical Optimization of Eigenvalues of Hermitian Matrix Functions
Mengi, Emre; Yıldırım, Emre Alper; Kılıç, Mustafa
2011-01-01
Copyright © by SIAM. Unauthorized reproduction of this article is prohibited. SIAM J. MATRIX ANAL. APPL. c 2014 Society for Industrial and Applied Mathematics Vol. 35, No. 2, pp. 699–724 NUMERICAL OPTIMIZATION OF EIGENVALUES OF HERMITIAN MATRIX FUNCTIONS∗ EMRE MENGI†, E. ALPER YILDIRIM ‡ , AND MUSTAFA KILIC¸ † Abstract. This work concerns the global minimization of a prescribed eigenvalue or a weighted sum of prescribed eigenvalues of a Hermitian matrix-valued func...
A Matrix-Free Algorithm for Multidisciplinary Design Optimization
Lambe, Andrew Borean
Multidisciplinary design optimization (MDO) is an approach to engineering design that exploits the coupling between components or knowledge disciplines in a complex system to improve the final product. In aircraft design, MDO methods can be used to simultaneously design the outer shape of the aircraft and the internal structure, taking into account the complex interaction between the aerodynamic forces and the structural flexibility. Efficient strategies are needed to solve such design optimization problems and guarantee convergence to an optimal design. This work begins with a comprehensive review of MDO problem formulations and solution algorithms. First, a fundamental MDO problem formulation is defined from which other formulations may be obtained through simple transformations. Using these fundamental problem formulations, decomposition methods from the literature are reviewed and classified. All MDO methods are presented in a unified mathematical notation to facilitate greater understanding. In addition, a novel set of diagrams, called extended design structure matrices, are used to simultaneously visualize both data communication and process flow between the many software components of each method. For aerostructural design optimization, modern decomposition-based MDO methods cannot efficiently handle the tight coupling between the aerodynamic and structural states. This fact motivates the exploration of methods that can reduce the computational cost. A particular structure in the direct and adjoint methods for gradient computation. motivates the idea of a matrix-free optimization method. A simple matrix-free optimizer is developed based on the augmented Lagrangian algorithm. This new matrix-free optimizer is tested on two structural optimization problems and one aerostructural optimization problem. The results indicate that the matrix-free optimizer is able to efficiently solve structural and multidisciplinary design problems with thousands of variables and
Optimizing Tpetra%3CU%2B2019%3Es sparse matrix-matrix multiplication routine.
Energy Technology Data Exchange (ETDEWEB)
Nusbaum, Kurtis Lee
2011-08-01
Over the course of the last year, a sparse matrix-matrix multiplication routine has been developed for the Tpetra package. This routine is based on the same algorithm that is used in EpetraExt with heavy modifications. Since it achieved a working state, several major optimizations have been made in an effort to speed up the routine. This report will discuss the optimizations made to the routine, its current state, and where future work needs to be done.
Directory of Open Access Journals (Sweden)
T. Vaupel
2004-01-01
Full Text Available Using integral equation methods for the analysis of complex (MMIC structures, the computation and storage effort for the solution of the linear systems of equations with their fully populated matrices still forms the main bottleneck. In the last years, remarkable improvements could be achieved by means of diakoptic methods and related preconditiners. In this contribution, we present a method based on the optimized decomposition of the system matrix depending on the circuit topology. The system matrix is splitted in a densely populated matrix and a mainly blockdiagonal matrix with overlapping submatrices. The latter matrix is used for the generation of high performance preconditioners within Krylov subspace methods using sparsified matrix storage methods, adaptive Cholesky decompositions and optimized forward/backward substitutions. Furthermore, we present an integration technique using a complete analytical treatment for the strongly oscillating parts of the spectral domain integrands allowing the analysis of very large structures as compared to the wavelength.
On Matrix-Valued Monge–Kantorovich Optimal Mass Transport
Ning, Lipeng; Georgiou, Tryphon T.; Tannenbaum, Allen
2016-01-01
We present a particular formulation of optimal transport for matrix-valued density functions. Our aim is to devise a geometry which is suitable for comparing power spectral densities of multivariable time series. More specifically, the value of a power spectral density at a given frequency, which in the matricial case encodes power as well as directionality, is thought of as a proxy for a “matrix-valued mass density.” Optimal transport aims at establishing a natural metric in the space of such matrix-valued densities which takes into account differences between power across frequencies as well as misalignment of the corresponding principle axes. Thus, our transportation cost includes a cost of transference of power between frequencies together with a cost of rotating the principle directions of matrix densities. The two endpoint matrix-valued densities can be thought of as marginals of a joint matrix-valued density on a tensor product space. This joint density, very much as in the classical Monge–Kantorovich setting, can be thought to specify the transportation plan. Contrary to the classical setting, the optimal transport plan for matrices is no longer supported on a thin zero-measure set. PMID:26997667
Stochastic sandwich method with low mode substitution for nucleon isovector matrix elements
Yang, Yi-Bo; Draper, Terrence; Gong, Ming; Liu, Keh-Fei
2015-01-01
We introduce a stochastic sandwich method with low-mode substitution to evaluate the connected three-point functions. The isovector matrix elements of the nucleon for the axial-vector coupling $g_A^3$, scalar couplings $g_S^3$ and the quark momentum fraction $\\langle x\\rangle_{u -d}$ are calculated with overlap fermion on 2+1 flavor domain-wall configurations on a $24^3 \\times 64$ lattice at $m_{\\pi} = 330$ MeV with lattice spacing $a = 0.114$ fm.
Matrix rigidity optimizes the polarization of stem cells
Zemel, Assaf; Rehfeldt, Florian; Brown, Andre; Discher, Dennis; Safran, Samuel
2009-03-01
We present a theoretical model and experiments to explain the non-monotonic dependence of stress-fiber polarization in stem cells on matrix rigidity. The theory generalizes the treatment of elastic inclusions to ``living'' inclusions (cells) whose active polarizability, unlike non-living matter, depends on the feedback of cellular forces that develop in response to matrix stresses. We demonstrate experimentally that the stress fibers in adult mesenchymal stem cells, generally orient parallel to the long axis of the cells, with an anisotropy that depends non-monotonically on substrate stiffness. Consistent with these experiments, our theory predicts that the magnitude of the cellular force increases monotonically with the matrix rigidity while the polarization anisotropy shows a maximum that depends on the cell shape and the elastic modulus of the medium. These findings offer a mechanical correlate for the observation that stem cell differentiation optimizes in a range of matrix rigidities that depends on the tissue type.
Dependency-based algorithms for vector processing of sparse matrix forward/backward substitutions
Energy Technology Data Exchange (ETDEWEB)
Vuong, G.T.; Chahine, R. [Hydro-Quebec, Montreal, Quebec (Canada); Granelli, G.P.; Montagna, M. [Univ. di Pavia (Italy)
1996-02-01
In this paper two algorithms for forward/backward substitutions and their implementation on vector computers are considered. A dependency-based substitution algorithm (DBSA) is proposed and compared with the well known W-matrix method. According to DBSA, the non-zero entries of the factor matrices are rearranged in groups of elements (slices) leading to independent operations. In the implementation of the W-matrix method, the non-zero elements of the inverse factors are grouped in sets (pseudocolumns) to overcome the problem of dependency between addition operations. Test cases, performed on a CRAY X-MP2/216 and a CRAY Y-MP8/464 vector computer, are taken from real life power system problems and consist in the solution of linear systems with up to 12,000 equations. The maximum speed-ups achieved (with respect to a code based on standard sparsity programming) are near to 7 for complex arithmetic and to 11 for real arithmetic.
Optimization of MIMO Systems Capacity Using Large Random Matrix Methods
Directory of Open Access Journals (Sweden)
Philippe Loubaton
2012-11-01
Full Text Available This paper provides a comprehensive introduction of large random matrix methods for input covariance matrix optimization of mutual information of MIMO systems. It is first recalled informally how large system approximations of mutual information can be derived. Then, the optimization of the approximations is discussed, and important methodological points that are not necessarily covered by the existing literature are addressed, including the strict concavity of the approximation, the structure of the argument of its maximum, the accuracy of the large system approach with regard to the number of antennas, or the justification of iterative water-filling optimization algorithms. While the existing papers have developed methods adapted to a specific model, this contribution tries to provide a unified view of the large system approximation approach.
Formulation Development and Optimization of Matrix Tablet of Tramadol Hydrochloride.
Deb, Pulak; Singha, Jubaraj; Chanda, Indranil; Chakraborty, Prithviraj
2017-01-01
The aim of the present investigation is to formulate and optimize oral sustained release matrix tablet of highly water soluble drug Tramadol HCl and to evaluate the effect of varying concentration of hydrophilic and hydrophobic polymer on drug release, based on a survey done on the recent patents of Tramadol HCl (US7374781, CA 2479252) and sustained release matrix tablets. The tablets were prepared by double granulation process, by melt granulation and wet granulation technique using Carnauba wax (CW) and HPMC K100 as release retardant. Pre and post compression factors were evaluated and all the parameters were found within the limit. The drug release data were subjected to different models in order to evaluate release kinetics and mechanism of drug release. The prepared formulations showed drug release in the range 100±2% in 6hrs, 7hrs, 8hrs and 9hrs and upto 12 hrs respectively. The optimized tablet having 25% CW and 20% HPMC showed sustained drug release pattern. Hydrophilic matrix of HPMC alone could not control the Tramadol release effectively for 12 h whereas when combined with CW could slow down the release of drug and can be successfully employed for formulating sustained-release matrix tablets. Similarity factor, f2 shows the test and reference profile are identical. Double granulation technique with CW and HPMC K100 proved as a better technique for sustaining the drug release from the matrix tablet. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.
Optimality criteria for the components of anisotropic constitutive matrix
DEFF Research Database (Denmark)
Pedersen, Pauli; Pedersen, Niels Leergaard
2014-01-01
densities is equal value for the weighted elastic energy densities, as a natural extension of the optimality criterion for a single load case. The second optimality criterion for the components of a constitutive matrix (of unit norm) is proportionality to corresponding weighted strain components...... with the same proportionality factor $widehat lambda $ for all the components, as shortly specified by $C_{i j k l} = widehat lambda sum _{n} eta _{n} (epsilon _{i j})_{n} (epsilon _{k l})_{n}$, in traditional notation (n indicate load case). These simple analytical results should be communicated, in spite...
Optimal power transaction matrix rescheduling under multilateral open access environment
Energy Technology Data Exchange (ETDEWEB)
Moghaddam, M.P.; Raoofat, M.; Haghifam, M.R. [Tarbiat Modarres University, Tehran (Iran). Department of Electrical Engineering
2004-09-01
This paper addresses a new concept for determining optimal transactions between different entities in a multilateral environment while benefits of both buyer and seller entities are taken into account with respect to the rules of the system. At the same time, constraints of the network are met, which leads to an optimal power flow problem. A modified power transaction matrix is proposed for modeling the environment. The optimization method in this paper is the continuation method, which is suited for complex situations of power system studies. This complexity will become more serious when dual interaction between financial and electrical subsystems of competitive power system are taken into account. The proposed approach is tested on a typical network with satisfactory results. (author)
Unifying time evolution and optimization with matrix product states
Haegeman, Jutho; Lubich, Christian; Oseledets, Ivan; Vandereycken, Bart; Verstraete, Frank
2016-10-01
We show that the time-dependent variational principle provides a unifying framework for time-evolution methods and optimization methods in the context of matrix product states. In particular, we introduce a new integration scheme for studying time evolution, which can cope with arbitrary Hamiltonians, including those with long-range interactions. Rather than a Suzuki-Trotter splitting of the Hamiltonian, which is the idea behind the adaptive time-dependent density matrix renormalization group method or time-evolving block decimation, our method is based on splitting the projector onto the matrix product state tangent space as it appears in the Dirac-Frenkel time-dependent variational principle. We discuss how the resulting algorithm resembles the density matrix renormalization group (DMRG) algorithm for finding ground states so closely that it can be implemented by changing just a few lines of code and it inherits the same stability and efficiency. In particular, our method is compatible with any Hamiltonian for which ground-state DMRG can be implemented efficiently. In fact, DMRG is obtained as a special case of our scheme for imaginary time evolution with infinite time step.
Thermoelectric Power In Misfit Cobaltites Ceramics: Optimization By Chemical Substitutions
Directory of Open Access Journals (Sweden)
Maignan, A.
2006-06-01
Full Text Available The ceramics of misfit cobaltites form a large family of layer oxides which exhibit large values of Seebeck coefficient (S300K ≥90μV.K-1. They can be divided in two categories depending on the number of the rocksalt-type (RS layers, n = 3 or n = 4, separating the [CoO2] conducting layers. From the comparison of their structural features, it is found that the S values are governed by the incommensurability ratio and/or the charge of the RS block. This is clearly evidenced by making chemical substitutions at the level of the RS block: isovalent but with cations of different ionic radius (rBa 2+ > rSr 2+ > rCa 2+ modifying the incommensurability ratio or aliovalent substitutions for cobalt (Pb4+, Ti4+ which keep unchanged the structural incommensurability but make the RS charge changing.
Las cerámicas basadas en cobaltitas forman una extensa familia de óxidos que presentan valores elevados del coeficiente seebeck (S300k ≥90 μV.K-1. Se pueden dividir en dos grupos dependiendo del número de capas con estructura de cloruro sódico (rocksalt - RS, n=3 ó n=4, que separan las capas conductoras de [CoO2] . Comparando sus caractetísticas estructurales, se ha encontrado que los valores de S están gobernados por la relación de inconmensurabilidad y la carga del bloque con estructura RS. Esto se evidencia claramente realizando sustituciones químicas en los bloques RS: Isobalentes con cationes de diferente radio (rBa 2+ > rSr 2+ > rCa 2+ que modifican la relación de inconmensurabilidad o sustituciones aliovalentes de cobalto (Pb4+, Ti4+ que provocan cambios en la carga del bloque RS pero no en la inconmensurabilidad.
Optimization of Al Matrix Reinforced with B4C Particles
Shabani, Mohsen Ostad; Mazahery, Ali
2013-02-01
In the current study, abrasive wear resistance and mechanical properties of A356 composite reinforced with B4C particulates were investigated. A center particle swarm optimization algorithm (CenterPSO) is proposed to predict the optimal process conditions in fabrication of aluminum matrix composites. Unlike other ordinary particles, the center particle has no explicit velocity and is set to the center of the swarm at every iteration. Other aspects of the center particle are the same as that of the ordinary particle, such as fitness evaluation and competition for the best particle of the swarm. Because the center of the swarm is a promising position, the center particle generally gets good fitness value. More importantly, due to frequent appearance as the best particle of swarm, it often attracts other particles and guides the search direction of the whole swarm.
Optimal control of complex networks based on matrix differentiation
Li, Guoqi; Ding, Jie; Wen, Changyun; Pei, Jing
2016-09-01
Finding the key node set to be connected to external control sources so as to minimize the energy for controlling a complex network, known as the minimum-energy control problem, is of critical importance but remains open. We address this critical problem where matrix differentiation is involved. To this end, the differentiation of energy/cost function with respect to the input matrix is obtained based on tensor analysis, and the Hessian matrix is compressed from a fourth-order tensor. Normalized projected gradient method (NPGM) normalized projected trust-region method (NPTM) are proposed with established convergence property. We show that NPGM is more computationally efficient than NPTM. Simulation results demonstrate satisfactory performance of the algorithms, and reveal important insights as well. Two interesting phenomena are observed. One is that the key node set tends to divide elementary paths equally. The other is that the low-degree nodes may be more important than hubs from a control point of view, indicating that controlling hub nodes does not help to lower the control energy. These results suggest a way of achieving optimal control of complex networks, and provide meaningful insights for future researches.
Mechanical properties of tyramine substituted-hyaluronan enriched fascia extracellular matrix.
Chin, Likang; Calabro, Anthony; Walker, Esteban; Derwin, Kathleen A
2012-03-01
Naturally occurring biomaterial scaffolds derived from extracellular matrix (ECM) have been the topic of recent investigation in the context of rotator cuff tendon repair. We previously reported a method to treat fascia ECM with high molecular weight tyramine substituted-hyaluronan (TS-HA) for use as a tendon augmentation scaffold. The presence of crosslinked TS-HA in fascia was associated with an increased macrophage and giant cell response compared to water-treated controls after implantation in a rat abdominal wall model. The objective of this study was to determine the extent to which TS-HA treatment was associated with mechanical property changes of fascia after implantation in the rat model. Fascia samples in all groups demonstrated time-dependent decreases in mechanical properties. TS-HA-treated fascia with crosslinking exhibited a lower toe modulus, a trend toward lower toe stiffness, and a higher transition strain than water-treated controls not only after implantation, but also at time zero. TS-HA treatment, with or without crosslinking, had no significant effect on time-zero or post-implantation load relaxation ratio, load relaxation rate, linear-region stiffness, or linear-region modulus. Our findings demonstrated that the particular TS-HA treatment employed in this study decreased the low-load elastic mechanical properties of fascia ECM, in keeping with the heightened macrophage and giant cell host response seen previously. This work provides a starting point and guidance for investigating alternative HA treatment strategies.
Chin, LiKang; Calabro, Anthony; Rodriguez, E. Rene; Tan, Carmela D.; Walker, Esteban
2011-01-01
Naturally-occurring biomaterial scaffolds derived from extracellular matrix (ECM) have been previously investigated for soft tissue repair. We propose to enrich fascia ECM with high molecular weight tyramine substituted-hyaluronan (TS-HA) to modulate inflammation associated with implantation and enhance fibroblast infiltration. As critical determinants of constructive remodeling, the host inflammatory response and macrophage polarization to TS-HA enriched fascia were characterized in a rat abdominal wall model. TS-HA treated fascia with cross-linking had a similar lymphocyte (P = 0.11) and plasma cell (P = 0.13) densities, greater macrophage (P = 0.001) and giant cell (P fascia, with or without cross-linking, exhibited a predominantly M2 pro-remodeling macrophage profile similar to water controls (P = 0.82), which is suggestive of constructive tissue remodeling. Our findings demonstrated that HA augmentation can alter the host response to an ECM, but the appropriate concentration and molecular weight needed to minimize chronic inflammation within the scaffold remains to be determined. PMID:21553156
Covariance matrix adaptation for multi-objective optimization.
Igel, Christian; Hansen, Nikolaus; Roth, Stefan
2007-01-01
The covariance matrix adaptation evolution strategy (CMA-ES) is one of the most powerful evolutionary algorithms for real-valued single-objective optimization. In this paper, we develop a variant of the CMA-ES for multi-objective optimization (MOO). We first introduce a single-objective, elitist CMA-ES using plus-selection and step size control based on a success rule. This algorithm is compared to the standard CMA-ES. The elitist CMA-ES turns out to be slightly faster on unimodal functions, but is more prone to getting stuck in sub-optimal local minima. In the new multi-objective CMAES (MO-CMA-ES) a population of individuals that adapt their search strategy as in the elitist CMA-ES is maintained. These are subject to multi-objective selection. The selection is based on non-dominated sorting using either the crowding-distance or the contributing hypervolume as second sorting criterion. Both the elitist single-objective CMA-ES and the MO-CMA-ES inherit important invariance properties, in particular invariance against rotation of the search space, from the original CMA-ES. The benefits of the new MO-CMA-ES in comparison to the well-known NSGA-II and to NSDE, a multi-objective differential evolution algorithm, are experimentally shown.
Speed optimized influence matrix processing in inverse treatment planning tools
Energy Technology Data Exchange (ETDEWEB)
Ziegenhein, Peter; Wilkens, Jan J; Nill, Simeon; Oelfke, Uwe [German Cancer Research Center (DKFZ), Department of Medical Physics in Radiation Oncology, Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Ludwig, Thomas [University of Heidelberg, Institute of Computer Science, Research Group Parallel and Distributed Systems, Im Neuenheimer Feld 348, 69120 Heidelberg (Germany)], E-mail: p.ziegenhein@dkfz.de, E-mail: u.oelfke@dkfz.de
2008-05-07
An optimal plan in modern treatment planning tools is found through the use of an iterative optimization algorithm, which deals with a high amount of patient-related data and number of treatment parameters to be optimized. Thus, calculating a good plan is a very time-consuming process which limits the application for patients in clinics and for research activities aiming for more accuracy. A common technique to handle the vast amount of radiation dose data is the concept of the influence matrix (DIJ), which stores the dose contribution of each bixel to the patient in the main memory of the computer. This study revealed that a bottleneck for the optimization time arises from the data transfer of the dose data between the memory and the CPU. In this note, we introduce a new method which speeds up the data transportation from stored dose data to the CPU. As an example we used the DIJ approach as is implemented in our treatment planning tool KonRad, developed at the German Cancer Research Center (DKFZ) in Heidelberg. A data cycle reordering method is proposed to take the advantage of modern memory hardware. This induces a minimal eviction policy which results in a memory behaviour exhibiting a 2.6 times faster algorithm compared to the naive implementation. Although our method is described for the DIJ approach implemented in KonRad, we believe that any other planning tool which uses a similar approach to store the dose data will also benefit from the described methods. (note)
He, Min; Storr-Paulsen, Thomas; Wang, Annie L.; Ghezzi, Chiara E.; Wang, Siran; Fullana, Matthew; Karamichos, Dimitrios; Utheim, Tor P.; Islam, Rakibul; Griffith, May; Islam, M. Mirazul; Hodges, Robin R.; Wnek, Gary E.; Kaplan, David L.; Dartt, Darlene A.
2016-01-01
Purpose We fabricated and investigated polymeric scaffolds that can substitute for the conjunctival extracellular matrix to provide a substrate for autologous expansion of human conjunctival goblet cells in culture. Methods We fabricated two hydrogels and two silk films: (1) recombinant human collagen (RHC) hydrogel, (2) recombinant human collagen 2-methacryloylxyethyl phosphorylcholine (RHC-MPC) hydrogel, (3) arginine-glycine-aspartic acid (RGD) modified silk, and (4) poly-D-lysine (PDL) coated silk, and four electrospun scaffolds: (1) collagen, (2) poly(acrylic acid) (PAA), (3) poly(caprolactone) (PCL), and (4) poly(vinyl alcohol) (PVA). Coverslips and polyethylene terephthalate (PET) were used for comparison. Human conjunctival explants were cultured on scaffolds for 9 to 15 days. Cell viability, outgrowth area, and the percentage of cells expressing markers for stratified squamous epithelial cells (cytokeratin 4) and goblet cells (cytokeratin 7) were determined. Results Most of cells grown on all scaffolds were viable except for PCL in which only 3.6 ± 2.2% of the cells were viable. No cells attached to PVA scaffold. The outgrowth was greatest on PDL-silk and PET. Outgrowth was smallest on PCL. All cells were CK7-positive on RHC-MPC while 84.7 ± 6.9% of cells expressed CK7 on PDL-silk. For PCL, 87.10 ± 3.17% of cells were CK7-positive compared to PET where 67.10 ± 12.08% of cells were CK7-positive cells. Conclusions Biopolymer substrates in the form of hydrogels and silk films provided for better adherence, proliferation, and differentiation than the electrospun scaffolds and could be used for conjunctival goblet cell expansion for eventual transplantation once undifferentiated and stratified squamous cells are included. Useful polymer scaffold design characteristics have emerged from this study. PMID:27832279
Mechanical Properties of Tyramine Substituted-Hyaluronan Enriched Fascia Extracellular Matrix
Chin, LiKang; Calabro, Anthony; Walker, Esteban; Derwin, Kathleen A.
2011-01-01
Naturally-occurring biomaterial scaffolds derived from extracellular matrix (ECM) have been the topic of recent investigation in the context of rotator cuff tendon repair. We previously reported a method to treat fascia ECM with high molecular weight tyramine substituted-hyaluronan (TS-HA) for use as a tendon augmentation scaffold. The presence of cross-linked TS-HA in fascia was associated with an increased macrophage and giant cell response compared to water treated controls after implantation in a rat abdominal wall model. The objective of this study was to determine the extent to which TS-HA treatment was associated with mechanical property changes of fascia after implantation in the rat model. Fascia samples in all groups demonstrated time-dependent decreases in mechanical properties. TS-HA treated fascia with cross-linking exhibited a lower toe modulus, a trend toward lower toe stiffness, and a higher transition strain than water treated controls not only after implantation, but also at time zero. TS-HA treatment, with or without cross-linking, had no significant effect on time-zero or post-implantation load relaxation ratio, load relaxation rate, linear-region stiffness, or linear-region modulus. Our findings demonstrated that the particular TS-HA treatment employed in this study decreased the low-load elastic mechanical properties of fascia ECM, in keeping with the heightened macrophage and giant cell host response seen previously. This work provides a starting point and guidance for investigating alternative HA treatment strategies. PMID:22238019
On the Limit Matrix Obtained in the Homogenization of an Optimal Control Problem
Indian Academy of Sciences (India)
S Kesavan; M Rajesh
2002-05-01
A new formulation for the limit matrix occurring in the cost functional of an optimal control problem on homogenization is obtained. It is used to obtain an upper bound for this matrix (in the sense of positive definite matrices).
Directory of Open Access Journals (Sweden)
Tiwary Bhupendra N
2010-06-01
Full Text Available Abstract Background Substituted catechols are important precursors for large-scale synthesis of pharmaceuticals and other industrial products. Most of the reported chemical synthesis methods are expensive and insufficient at industrial level. However, biological processes for production of substituted catechols could be highly selective and suitable for industrial purposes. Results We have optimized a process for bio-catalytic production of 3-substituted catechols viz. 3-nitrocatechol (3-NC and 3-methylcatechol (3-MC at pilot scale. Amongst the screened strains, two strains viz. Pseudomonas putida strain (F1 and recombinant Escherichia coli expression clone (pDTG602 harboring first two genes of toluene degradation pathway were found to accumulate 3-NC and 3-MC respectively. Various parameters such as amount of nutrients, pH, temperature, substrate concentration, aeration, inoculums size, culture volume, toxicity of substrate and product, down stream extraction, single step and two-step biotransformation were optimized at laboratory scale to obtain high yields of 3-substituted catechols. Subsequently, pilot scale studies were performed in 2.5 liter bioreactor. The rate of product accumulation at pilot scale significantly increased up to ~90-95% with time and high yields of 3-NC (10 mM and 3-MC (12 mM were obtained. Conclusion The biocatalytic production of 3-substituted catechols viz. 3-NC and 3-MC depend on some crucial parameters to obtain maximum yields of the product at pilot scale. The process optimized for production of 3-substituted catechols by using the organisms P. putida (F1 and recombinant E. coli expression clone (pDTG602 may be useful for industrial application.
Nagashima, Hiroki; Nakajima, Yoshiki; Shen, Jian-Ren; Mino, Hiroyuki
2015-01-01
Proton matrix ENDOR spectra were measured for Ca2+-depleted and Sr2+-substituted photosystem II (PSII) membrane samples from spinach and core complexes from Thermosynechococcus vulcanus in the S2 state. The ENDOR spectra obtained were similar for untreated PSII from T. vulcanus and spinach, as well as for Ca2+-containing and Sr2+-substituted PSII, indicating that the proton arrangements around the manganese cluster in cyanobacterial and higher plant PSII and Ca2+-containing and Sr2+-substituted PSII are similar in the S2 state, in agreement with the similarity of the crystal structure of both Ca2+-containing and Sr2+-substituted PSII in the S1 state. Nevertheless, slightly different hyperfine separations were found between Ca2+-containing and Sr2+-substituted PSII because of modifications of the water protons ligating to the Sr2+ ion. Importantly, Ca2+ depletion caused the loss of ENDOR signals with a 1.36-MHz separation because of the loss of the water proton W4 connecting Ca2+ and YZ directly. With respect to the crystal structure and the functions of Ca2+ in oxygen evolution, it was concluded that the roles of Ca2+ and Sr2+ involve the maintenance of the hydrogen bond network near the Ca2+ site and electron transfer pathway to the manganese cluster. PMID:26438823
Directory of Open Access Journals (Sweden)
Li-Ling Tseng
2013-12-01
Conclusion: The results indicated that ECM proteins increased cell attachment to bone substitutes in vitro. The preferential affinity of different bone substitutes to certain ECM proteins was evident. Cerasorb and BoneCeramic had better MG63 human osteosarcoma cell adhesion ability than Bio-Oss and MBCP.
THE OPTIMAL TIME FOR SUBSTITUTION OF Eucalyptus spp. PLANTATIONS –THE TECHNOLOGICAL PROGRESS CASE
Directory of Open Access Journals (Sweden)
José Luiz Pereira de Rezende
2005-03-01
Full Text Available The importance of technological progress for the Brazilian forest enterprises cannot be denied. Its influencecomprehends all the activities, but can be summarized in the increase of income via yield increase or cost reduction and, mainly,in the two cases occurring together. Technological effects influence, among other aspects, the cutting age and the optimal time torenewal (a new plantinting or “reforma” Eucalyptus plantations. Studies to determine these times are not so common in theliterature since it requires both forestry and economic knowledge. Before renewing an Eucalyptus stand, it is necessary totechnically and economically to define the optimal cut age the original planting and the coppicings and after how many cuttingsthe substitution of the plantations should be done. This study aimed at studying the optimal time to substitute Eucalyptus spp.Plantations, considering the gains earned through technological progress; to determine the cutting age of the population, theincome being increasing and the cost being decreasing; to propose and verify the efficiency of a mathematical model whichallows modeling the effects of technological progress; to study the substitution chain between 1960 and 2000 and between 2000and 2040, considering technological progress; and to test the results in a case study. The Gompertz Function was employed toobtain the volumes at the various ages. The criterion employed for the economic evaluation of the projects was the Presente NetValue (PNV. The proposed model allowed the calculation of yields and costs through time, study the effect of yield increaseand cost reduction and determine the rates of these increase and, or, reductions as well as determining rates which served asmoderators so that the yield and costs did not reach unreal values. It was concluded that: The rotation, with current values, is at 7years of age; the model proved to be efficient for estimates up to 40 years; with the income and costs from
Tregre, Gregory Jude
A series of all-hydrocarbon thermoset composite matrix resins was synthesized via electrophilic substitution of cyclopentadiene, indene, and fluorene ring systems with allyl and/or propargyl halides under phase transfer conditions. Reaction of cyclopentadiene with allyl chloride (ACP resin), propargyl bromide (PCP resin) or various feed ratios of allyl chloride and propargyl bromide (APCP resins) yielded mixtures of products with 2-6 substituents per cyclopentadiene ring. Reaction of indene with allyl chloride (Al resins) or propargyl bromide (PI resins) yielded mixtures of products with 2-4 substituents per indene. In both sets of resins the allyl functionality obtained a greater average degree of substitution than the analogous propargyl species. Differential scanning calorimetric (DSC) analysis of the multifunctional resins showed broad, high-energy thermal cures in all cases. The enthalpies of cure for ACP and PCP were 750 J/g and 805 J/g, respectively, with peak cure energies occurring at 310 and 248sp°C. The enthalpy of cure for APCP resins ranged from 750 J/g to 800 J/g with higher propargyl-functional resins yielding higher enthalpies of cure. Physically mixed ACP/PCP resin systems gave peak cure temperatures and energy values comparable to APCP resins. The enthalpies of cure for Al and PI-resins were 480 J/g and 630 J/g, respectively. Peak cure temperature for Al resin was 320sp°C, while the peak cure for PI resin occurred at 282sp°C. Infrared spectroscopy (IR) and nuclear magnetic resonance spectroscopy (NMR) were used to evaluate mechanisms of cure in the experimental resins. The allyl functional resins cured through a combination of ene reactions and polyaddition reactions. The propargyl functional resins cured through ene reactions and polyadditions but also underwent some cyclotrimerization of the propargyl functionalities. A small amount of autoxidation was seen in all of the resins. Thermal stability and carbon yields of the cured resins were
López-Calzada, G; Hernandez-Martínez, A R; Cruz-Soto, M; Ramírez-Cardona, M; Rangel, D; Molina, G A; Luna-Barcenas, G; Estevez, M
2016-04-01
Despite the significant advances in the meniscus tissue engineering field, it is difficult to recreate the complex structure and organization of the collagenous matrix of the meniscus. In this work, we developed a meniscus prototype to be used as substitute or scaffold for the regeneration of the meniscal matrix, recreating the differential morphology of the meniscus by electrospinning. Synthetic biocompatible polymers were combined with the extracellular matrix component, collagen and used to replicate the meniscus. We studied the correlation between mechanical and structural properties of the polymer blend as a function of collagen concentration. Fibers were collected on a surface of a rapidly rotating precast mold, to accurately replicate each sectional morphology of the meniscus; different electro-tissues were produced. Detailed XRD analyses exhibited structural changes developed by electrospinning. We achieved to integrate all these electro-tissues to form a complete synthetic meniscus. Vascularization tests were performed to assess the potential use of our novel polymeric blend for promising meniscus regeneration.
Problems on Solving Matrix Aggregation in Group Decision-Making by Glowworm Swarm Optimization
Yaping Li
2016-01-01
Judgment matrix aggregation, as an important part of group decision-making, has been widely and deeply studied due to the universality and importance of group decision-making in the management field. For the variety of judgment matrix in group decision-making, the matrix aggregation result can be obtained by using the mode of glowworm swarm optimization. First, this paper introduces the basic principle of the glowworm swarm optimization (GSO) algorithm and gives the improved GSO algorithm to ...
The Optimization on Ranks and Inertias of a Quadratic Hermitian Matrix Function and Its Applications
Directory of Open Access Journals (Sweden)
Yirong Yao
2013-01-01
Full Text Available We solve optimization problems on the ranks and inertias of the quadratic Hermitian matrix function subject to a consistent system of matrix equations and . As applications, we derive necessary and sufficient conditions for the solvability to the systems of matrix equations and matrix inequalities , and in the Löwner partial ordering to be feasible, respectively. The findings of this paper widely extend the known results in the literature.
Optimal matrix rigidity for stress fiber polarization in stem cells
Rehfeldt, F.; Brown, A. E. X.; Discher, D. E.; Safran, S. A.
2010-01-01
The shape and differentiation of human mesenchymal stem cells is especially sensitive to the rigidity of their environment; the physical mechanisms involved are unknown. A theoretical model and experiments demonstrate here that the polarization/alignment of stress-fibers within stem cells is a non-monotonic function of matrix rigidity. We treat the cell as an active elastic inclusion in a surrounding matrix whose polarizability, unlike dead matter, depends on the feedback of cellular forces that develop in response to matrix stresses. The theory correctly predicts the monotonic increase of the cellular forces with the matrix rigidity and the alignment of stress-fibers parallel to the long axis of cells. We show that the anisotropy of this alignment depends non-monotonically on matrix rigidity and demonstrate it experimentally by quantifying the orientational distribution of stress-fibers in stem cells. These findings offer a first physical insight for the dependence of stem cell differentiation on tissue elasticity. PMID:20563235
Bonferoni, MC; Rossi, S; Ferrari, F; Bertoni, M; Bolhuis, GK; Caramella, C
1998-01-01
The lambda carrageenan/HPMC ratio in matrix tablets has been optimized in order to obtain pH-independent release profiles of chlorpheniramine maleate, a freely soluble drug. Release profiles in acidic (pH 1.2) and neutral (pH 6.8) media were fitted according to the Weibull and the power law models.
Random matrix theory for portfolio optimization: a stability approach
Sharifi, S.; Crane, M.; Shamaie, A.; Ruskin, H.
2004-04-01
We apply random matrix theory (RMT) to an empirically measured financial correlation matrix, C, and show that this matrix contains a large amount of noise. In order to determine the sensitivity of the spectral properties of a random matrix to noise, we simulate a set of data and add different volumes of random noise. Having ascertained that the eigenspectrum is independent of the standard deviation of added noise, we use RMT to determine the noise percentage in a correlation matrix based on real data from S&P500. Eigenvalue and eigenvector analyses are applied and the experimental results for each of them are presented to identify qualitatively and quantitatively different spectral properties of the empirical correlation matrix to a random counterpart. Finally, we attempt to separate the noisy part from the non-noisy part of C. We apply an existing technique to cleaning C and then discuss its associated problems. We propose a technique of filtering C that has many advantages, from the stability point of view, over the existing method of cleaning.
Oostendorp, Corien; Meyer, Sarah; Sobrio, Monia; van Arendonk, Joyce; Reichmann, Ernst; Daamen, Willeke F; van Kuppevelt, Toin H
2017-05-01
Treatment of full-thickness skin defects with split-thickness skin grafts is generally associated with contraction and scar formation and cellular skin substitutes have been developed to improve skin regeneration. The evaluation of cultured skin substitutes is generally based on qualitative parameters focusing on histology. In this study we focused on quantitative evaluation to provide a template for comparison of human bio-engineered skin substitutes between clinical and/or research centers, and to supplement histological data. We focused on extracellular matrix proteins since these components play an important role in skin regeneration. As a model we analyzed the human dermal substitute denovoDerm and the dermo-epidermal skin substitute denovoSkin. The quantification of the extracellular matrix proteins type III collagen and laminin 5 in tissue homogenates using western blotting analysis and ELISA was not successful. The same was true for assaying lysyl oxidase, an enzyme involved in crosslinking of matrix molecules. As an alternative, gene expression levels were measured using qPCR. Various RNA isolation procedures were probed. The gene expression profile for specific dermal and epidermal genes could be measured reliably and reproducibly. Differences caused by changes in the cell culture conditions could easily be detected. The number of cells in the skin substitutes was measured using the PicoGreen dsDNA assay, which was found highly quantitative and reproducible. The (dis) advantages of assays used for quantitative evaluation of skin substitutes are discussed.
Pena, Ana-Maria; Fagot, Dominique; Olive, Christian; Michelet, Jean-François; Galey, Jean-Baptiste; Leroy, Frédéric; Beaurepaire, Emmanuel; Martin, Jean-Louis; Colonna, Anne; Schanne-Klein, Marie-Claire
2010-09-01
Dermal fibroblasts are responsible for the generation of mechanical forces within their surrounding extracellular matrix and can be potentially targeted by anti-aging ingredients. Investigation of the modulation of fibroblast contraction by these ingredients requires the implementation of three-dimensional in situ imaging methodologies. We use multiphoton microscopy to visualize unstained engineered dermal tissue by combining second-harmonic generation that reveals specifically fibrillar collagen and two-photon excited fluorescence from endogenous cellular chromophores. We study the fibroblast-induced reorganization of the collagen matrix and quantitatively evaluate the effect of Y-27632, a RhoA-kinase inhibitor, on dermal substitute contraction. We observe that collagen fibrils rearrange around fibroblasts with increasing density in control samples, whereas collagen fibrils show no remodeling in the samples containing the RhoA-kinase inhibitor. Moreover, we show that the inhibitory effects are reversible. Our study demonstrates the relevance of multiphoton microscopy to visualize three-dimensional remodeling of the extracellular matrix induced by fibroblast contraction or other processes.
Yu, Guanying; Ye, Lan; Tan, Wei; Zhu, Xuguo; Li, Yaonan; Jiang, Duyin
2016-03-01
The extensive skin defects induced by severe burns are dangerous and can be fatal. Currently, the most common therapy is tangential excision to remove the necrotic or denatured areas of skin, followed by skin grafting. Xenogeneic dermal substitutes, such as porcine acellular dermal matrix (ADM), are typically used to cover the burn wounds, and may accelerate wound healing. It is assumed that burned skin that still maintains partial biological activity may be recycled to construct an autologous acellular dermal matrix, termed 'deep‑degree burned dermal matrix (DDBDM)'. In theory, DDBDM may avoid the histoincompatibility issues associated with foreign or xenogeneic dermal matrices, and reduce therapy costs by making full use of discarded skin. In the present study, the collagens within prepared DDBDM were thickened, disorganized and partially fractured, however, they still maintained their reticular structure and tensile strength (Pburn toxins. Following 4 weeks of subcutaneous implantation, ADM and DDBDM were incompletely degraded and maintained good integrity. No significant inflammatory reaction or rejection were observed, which indicated that ADM and DDBDM have good histocompatibility. Therefore, DDBDM may be a useful material for the treatment of deep‑degree burns.
Optimization of photovoltaic energy production through an efficient switching matrix
Directory of Open Access Journals (Sweden)
Pietro Romano
2013-09-01
Full Text Available This work presents a preliminary study on the implementation of a new system for power output maximization of photovoltaic generators under non-homogeneous conditions. The study evaluates the performance of an efficient switching matrix and the relevant automatic reconfiguration control algorithms. The switching matrix is installed between the PV generator and the inverter, allowing a large number of possible module configurations. PV generator, switching matrix and the intelligent controller have been simulated in Simulink. The proposed reconfiguration system improved the energy extracted by the PV generator under non-uniform solar irradiation conditions. Short calculation times of the proposed control algorithms allow its use in real time applications even where a higher number of PV modules is required.
Random matrix theory and portfolio optimization in Moroccan stock exchange
El Alaoui, Marwane
2015-09-01
In this work, we use random matrix theory to analyze eigenvalues and see if there is a presence of pertinent information by using Marčenko-Pastur distribution. Thus, we study cross-correlation among stocks of Casablanca Stock Exchange. Moreover, we clean correlation matrix from noisy elements to see if the gap between predicted risk and realized risk would be reduced. We also analyze eigenvectors components distributions and their degree of deviations by computing the inverse participation ratio. This analysis is a way to understand the correlation structure among stocks of Casablanca Stock Exchange portfolio.
Problems on Solving Matrix Aggregation in Group Decision-Making by Glowworm Swarm Optimization
Directory of Open Access Journals (Sweden)
Yaping Li
2016-01-01
Full Text Available Judgment matrix aggregation, as an important part of group decision-making, has been widely and deeply studied due to the universality and importance of group decision-making in the management field. For the variety of judgment matrix in group decision-making, the matrix aggregation result can be obtained by using the mode of glowworm swarm optimization. First, this paper introduces the basic principle of the glowworm swarm optimization (GSO algorithm and gives the improved GSO algorithm to solve the matrix aggregation problems. In this approach, the consistency ratio is introduced to the objective function of the glowworm swarm optimization, thus reducing the subjectivity and information loss in the aggregation process. Then, the improved GSO algorithm is applied to the solution of the deterministic matrix and the fuzzy matrix. The method optimization can provide an effective and relatively uniform aggregation method for matrix aggregation. Finally, through comparative analysis, it is shown that the method of this paper has certain advantages in terms of adaptability, accuracy, and stability to solving the matrix aggregation problems.
Bernoulli substitution in the Ramsey model: Optimal trajectories under control constraints
Krasovskii, A. A.; Lebedev, P. D.; Tarasyev, A. M.
2017-05-01
We consider a neoclassical (economic) growth model. A nonlinear Ramsey equation, modeling capital dynamics, in the case of Cobb-Douglas production function is reduced to the linear differential equation via a Bernoulli substitution. This considerably facilitates the search for a solution to the optimal growth problem with logarithmic preferences. The study deals with solving the corresponding infinite horizon optimal control problem. We consider a vector field of the Hamiltonian system in the Pontryagin maximum principle, taking into account control constraints. We prove the existence of two alternative steady states, depending on the constraints. A proposed algorithm for constructing growth trajectories combines methods of open-loop control and closed-loop regulatory control. For some levels of constraints and initial conditions, a closed-form solution is obtained. We also demonstrate the impact of technological change on the economic equilibrium dynamics. Results are supported by computer calculations.
Optimal Pole Assignment of Linear Systems by the Sylvester Matrix Equations
Directory of Open Access Journals (Sweden)
Hua-Feng He
2014-01-01
class of linear matrix equations, necessary and sufficient conditions for the existence of a solution to the optimal pole assignment problem are proposed in this paper. By properly choosing the free parameters in the parametric solutions to this class of linear matrix equations, complete solutions to the optimal pole assignment problem can be obtained. A numerical example is used to illustrate the effectiveness of the proposed approach.
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Asghar Vatani Oskouie
2016-12-01
Full Text Available In this article the general non-symmetric parametric form of the incremental secant stiffness matrix for nonlinear analysis of solids have been investigated to present a semi analytical sensitivity analysis approach for geometric nonlinear shape optimization. To approach this aim the analytical formulas of secant stiffness matrix are presented. The models were validated and used to perform investigating different parameters affecting the shape optimization. Numerical examples utilized for this investigating sensitivity analysis with detailed discussions presented.
Petrović, Jelena; Ibrić, Svetlana; Betz, Gabriele; Đurić, Zorica
2012-05-30
The main objective of the study was to develop artificial intelligence methods for optimization of drug release from matrix tablets regardless of the matrix type. Static and dynamic artificial neural networks of the same topology were developed to model dissolution profiles of different matrix tablets types (hydrophilic/lipid) using formulation composition, compression force used for tableting and tablets porosity and tensile strength as input data. Potential application of decision trees in discovering knowledge from experimental data was also investigated. Polyethylene oxide polymer and glyceryl palmitostearate were used as matrix forming materials for hydrophilic and lipid matrix tablets, respectively whereas selected model drugs were diclofenac sodium and caffeine. Matrix tablets were prepared by direct compression method and tested for in vitro dissolution profiles. Optimization of static and dynamic neural networks used for modeling of drug release was performed using Monte Carlo simulations or genetic algorithms optimizer. Decision trees were constructed following discretization of data. Calculated difference (f(1)) and similarity (f(2)) factors for predicted and experimentally obtained dissolution profiles of test matrix tablets formulations indicate that Elman dynamic neural networks as well as decision trees are capable of accurate predictions of both hydrophilic and lipid matrix tablets dissolution profiles. Elman neural networks were compared to most frequently used static network, Multi-layered perceptron, and superiority of Elman networks have been demonstrated. Developed methods allow simple, yet very precise way of drug release predictions for both hydrophilic and lipid matrix tablets having controlled drug release.
Jiang, Zhaolin; Shen, Nuo; Zhou, Jianwei
2013-01-01
We first give the style spectral decomposition of a special skew circulant matrix C and then get the style decomposition of arbitrary skew circulant matrix by making use of the Kronecker products between the elements of first row in skew circulant and the special skew circulant C. Besides that, we obtain the singular value of skew circulant matrix as well. Finally, we deal with the optimal backward perturbation analysis for the linear system with skew circulant coefficient matrix on the base of its style spectral decomposition. PMID:24369488
Energy Technology Data Exchange (ETDEWEB)
Goodwin, D. L.; Kuprov, Ilya, E-mail: i.kuprov@soton.ac.uk [School of Chemistry, University of Southampton, Highfield Campus, Southampton SO17 1BJ (United Kingdom)
2015-08-28
Auxiliary matrix exponential method is used to derive simple and numerically efficient general expressions for the following, historically rather cumbersome, and hard to compute, theoretical methods: (1) average Hamiltonian theory following interaction representation transformations; (2) Bloch-Redfield-Wangsness theory of nuclear and electron relaxation; (3) gradient ascent pulse engineering version of quantum optimal control theory. In the context of spin dynamics, the auxiliary matrix exponential method is more efficient than methods based on matrix factorizations and also exhibits more favourable complexity scaling with the dimension of the Hamiltonian matrix.
Goodwin, D. L.; Kuprov, Ilya
2015-08-01
Auxiliary matrix exponential method is used to derive simple and numerically efficient general expressions for the following, historically rather cumbersome, and hard to compute, theoretical methods: (1) average Hamiltonian theory following interaction representation transformations; (2) Bloch-Redfield-Wangsness theory of nuclear and electron relaxation; (3) gradient ascent pulse engineering version of quantum optimal control theory. In the context of spin dynamics, the auxiliary matrix exponential method is more efficient than methods based on matrix factorizations and also exhibits more favourable complexity scaling with the dimension of the Hamiltonian matrix.
Directory of Open Access Journals (Sweden)
2008-03-01
Full Text Available In the present study polyacrylamide (PAm-gelatin-hydroxyapatite (HA composites have been synthesized by suspension polymerization method. The prepared composites were characterized by Fourier transform spectroscopy (FTIR which revealed the presence of functional groups in the composite. The X-ray diffraction (XRD studies indicated that HA powder was present in nano size. Thermogravimetric analysis (TGA revealed that composite is more thermally stable than the polymer matrix alone. The morphology of composite studied by optical microscopy (OPM and scanning electron microscopy (SEM suggested that pore size was between 3–20 µm. The composites showed adequately good mechanical properties as evident from the varying compressive strength and modulus in the range 31.57±8.16 MPa and 745±388 MPa, respectively. The water sorption behavior was found to be dependent on the chemical composition of the matrix and the sorption data were used to calculate network parameters. The porosity of composite varied between 4 to 30.66%.The in vitro blood compatibility indicated that the adsorption of bovine serum albumin (BSA varied from 0.11 to 0.24 mg•g–1, the percentage haemolysis was between 2.4 to 6.9% and the weight of blood clot formed on the composite surfaces were found in the range 11 to 52 mg.
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
The performance of analytical derivative and sparse matrix techniques applied to a traditional densesequential quadratic programming(SQP) is studied, and the strategy utilizing those techniques is also presented. Computational results on two typicalchemical optimization problems demonstrate significant enhancement in efficiency, which shows this strategy ispromising and suitable for large-scale process optimization problems.
Performance modeling and optimization of sparse matrix-vector multiplication on NVIDIA CUDA platform
Xu, S.; Xue, W.; Lin, H.X.
2011-01-01
In this article, we discuss the performance modeling and optimization of Sparse Matrix-Vector Multiplication (SpMV) on NVIDIA GPUs using CUDA. SpMV has a very low computation-data ratio and its performance is mainly bound by the memory bandwidth. We propose optimization of SpMV based on ELLPACK from
Performance modeling and optimization of sparse matrix-vector multiplication on NVIDIA CUDA platform
Xu, S.; Xue, W.; Lin, H.X.
2011-01-01
In this article, we discuss the performance modeling and optimization of Sparse Matrix-Vector Multiplication (SpMV) on NVIDIA GPUs using CUDA. SpMV has a very low computation-data ratio and its performance is mainly bound by the memory bandwidth. We propose optimization of SpMV based on ELLPACK from
Integrated optomechanical structural optimization through coupling of sensitivity matrixes
Riva, M.; Moschetti, M.
2016-07-01
The design of astronomical instrument is growing in dimension and complexity following ELT class telescopes. The availability of new structural material like composite ones is asking for more robust and reliable designing numerical tools. This paper wants to show a new opto-mechanical optimization approach developed starting from a previously developed integrated design framework. The Idea is to reduce number of iteration in a multi- variable structural optimization taking advantage of the embedded sensitivity routines that are available both in FEA software and in raytracing ones. This approach provide reduced iteration number mainly in case of high number of structural variable parameters.
Extensions of linear-quadratic control, optimization and matrix theory
Jacobson, David H
1977-01-01
In this book, we study theoretical and practical aspects of computing methods for mathematical modelling of nonlinear systems. A number of computing techniques are considered, such as methods of operator approximation with any given accuracy; operator interpolation techniques including a non-Lagrange interpolation; methods of system representation subject to constraints associated with concepts of causality, memory and stationarity; methods of system representation with an accuracy that is the best within a given class of models; methods of covariance matrix estimation;methods for low-rank mat
Jiang, Hong; Zuo, Yi; Zhang, Li; Li, Jidong; Zhang, Aiming; Li, Yubao; Yang, Xiaochao
2014-03-01
Each approach for artificial cornea design is toward the same goal: to develop a material that best mimics the important properties of natural cornea. Accordingly, the selection and optimization of corneal substitute should be based on their physicochemical properties. In this study, three types of polyvinyl alcohol (PVA) hydrogels with different polymerization degree (PVA1799, PVA2499 and PVA2699) were prepared by freeze-thawing techniques. After characterization in terms of transparency, water content, water contact angle, mechanical property, root-mean-square roughness and protein adsorption behavior, the optimized PVA2499 hydrogel with similar properties of natural cornea was selected as a matrix material for artificial cornea. Based on this, a biomimetic artificial cornea was fabricated with core-and-skirt structure: a transparent PVA hydrogel core, surrounding by a ringed PVA-matrix composite skirt that composed of graphite, Fe-doped nano hydroxyapatite (n-Fe-HA) and PVA hydrogel. Different ratio of graphite/n-Fe-HA can tune the skirt color from dark brown to light brown, which well simulates the iris color of Oriental eyes. Moreover, morphologic and mechanical examination showed that an integrated core-and-skirt artificial cornea was formed from an interpenetrating polymer network, no phase separation appeared on the interface between the core and the skirt.
Sequential optimization of matrix chain multiplication relative to different cost functions
Chikalov, Igor
2011-01-01
In this paper, we present a methodology to optimize matrix chain multiplication sequentially relative to different cost functions such as total number of scalar multiplications, communication overhead in a multiprocessor environment, etc. For n matrices our optimization procedure requires O(n 3) arithmetic operations per one cost function. This work is done in the framework of a dynamic programming extension that allows sequential optimization relative to different criteria. © 2011 Springer-Verlag Berlin Heidelberg.
Misochko, Eugenii Ya; Masitov, Artem A; Akimov, Alexander V; Korchagin, Denis V; Chapyshev, Sergei V
2015-03-19
The heavy atom effect on the magnetic anisotropy of septet trinitrenes is reported. Septet 1-bromo-3,5-dichloro-2,4,6-trinitrenobenzene (S-1) was generated in a solid argon matrix by ultraviolet irradiation of 1,3,5-triazido-2-bromo-4,6-dichlorobenzene. This trinitrene displays an electron spin resonance (ESR) spectrum that drastically differs from ESR spectra of all previously studied septet trinitrenes. The zero-field splitting (ZFS) parameters, derived from the experimental spectrum, show the parameter |D| = 0.1237 cm(-1) and the unprecedentedly large ratio of E/D = 0.262 that is close to the rhombic limit E/D = 1/3 for high-spin molecules. The CASCI (based on state-averaged CASSCF) and DFT methods were applied to calculate the ZFS tensor focusing on the heavy (bromine) atom effects on the spin-orbit term. These calculations show that the multiconfigurational ab initio formalism and the CASCI method are the most successful for accurate predictions of the spin-orbit term in the ZFS tensor of high-spin nitrenes containing heavy bromine atoms. Due to the presence of the bromine atom in S-1, the contribution of the spin-orbit term to the total parameter D is dominant and responsible for the unusual orientation of the easy Z-axis lying in the molecular plane perpendicular to the C-Br bond. As a result, the principal values D(XX), D(YY), and D(ZZ) of the total tensor D̂(Tot) have such magnitudes and signs for which the ratio E/D is close to the rhombic limit, and the total parameter D is large in magnitude and positive in sign.
Optimization of Data Requests Timing by Working with Matrixes under MSAccess Environment
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Alexandru ATOMEI
2010-09-01
Full Text Available This paper is going to emphasize an optimised code in order to manage matrix calculus under MSAccess. The economic impact of using such a method is the optimal cost-benefit solution, and optimised timing for data management. As well, matrix calculus is the base of Variance-Covariance method used by financial corporations as an advanced method for estimation of market risk movements with direct impact over the capital required by prudential bodies.
OPTIMAL APPROXIMATE SOLUTION OF THE MATRIX EQUATION AXB=C OVER SYMMETRIC MATRICES
Institute of Scientific and Technical Information of China (English)
Anping Liao; Yuan Lei
2007-01-01
Let SE denote the least-squares symmetric solution set of the matrix equation AXB=C,where A,B and C are given matrices of suitable size.To find the optimal approximate solution in the set SE to a given matrix,we give a new feasible method based on the projection theorem,the generalized SVD and the canonical correction decomposition.
Goodwin, David; Kuprov, Ilya
2015-01-01
Auxiliary matrix exponential method is used to derive simple and numerically efficient general expressions for the following, historically rather cumbersome, and hard to compute, theoretical methods: (1) average Hamiltonian theory following interaction representation transformations; (2) Bloch-Redfield-Wangsness theory of nuclear and electron relaxation; (3) gradient ascent pulse engineering version of quantum optimal control theory. In the context of spin dynamics, the auxiliary matrix expon...
Optimal control of large space structures via generalized inverse matrix
Nguyen, Charles C.; Fang, Xiaowen
1987-01-01
Independent Modal Space Control (IMSC) is a control scheme that decouples the space structure into n independent second-order subsystems according to n controlled modes and controls each mode independently. It is well-known that the IMSC eliminates control and observation spillover caused when the conventional coupled modal control scheme is employed. The independent control of each mode requires that the number of actuators be equal to the number of modelled modes, which is very high for a faithful modeling of large space structures. A control scheme is proposed that allows one to use a reduced number of actuators to control all modeled modes suboptimally. In particular, the method of generalized inverse matrices is employed to implement the actuators such that the eigenvalues of the closed-loop system are as closed as possible to those specified by the optimal IMSC. Computer simulation of the proposed control scheme on a simply supported beam is given.
Herrmann, Markus; Nkuiya, Bruno
2016-05-15
This paper designs a bio-economic model to examine the use of substitute antibiotic drugs (analogs) sold by an industry that has open access to the resource of the antibiotic class's susceptibility (treatment effectiveness). Antibiotics are characterized by different expected recovery rates and production costs, which in conjunction with the class's treatment susceptibility determines their relative effectiveness. Our analysis reveals that the high-quality antibiotic drug loses its comparative advantage over time making the low-quality drug the treatment of last resort in the market equilibrium and the social optimum when antibiotic susceptibility cannot replenish. However, when antibiotic susceptibility is renewable, both antibiotics may be used in the long run, and the comparative advantage of the high-quality drug may be restored in the social optimum that allows lowering infection in the long run. We develop the optimal tax/subsidy scheme that would induce antibiotic producers under open access to behave optimally and account for the social cost of infection and value of antibiotic susceptibility. We show that the welfare loss associated with the uncorrected open-access allocation is highest; when the resource of antibiotic susceptibility is non-renewable, high morbidity costs are incurred by individuals, and low social discount rates apply. Copyright © 2016 John Wiley & Sons, Ltd.
Near-Optimal Algorithms for Online Matrix Prediction
Hazan, Elad; Shalev-Shwartz, Shai
2012-01-01
In several online prediction problems of recent interest the comparison class is composed of matrices with bounded entries. For example, in the online max-cut problem, the comparison class is matrices which represent cuts of a given graph and in online gambling the comparison class is matrices which represent permutations over n teams. Another important example is online collaborative filtering in which a widely used comparison class is the set of matrices with a small trace norm. In this paper we isolate a property of matrices, which we call (beta,tau)-decomposability, and derive an efficient online learning algorithm, that enjoys a regret bound of O*(sqrt(beta tau T)) for all problems in which the comparison class is composed of (beta,tau)-decomposable matrices. By analyzing the decomposability of cut matrices, triangular matrices, and low trace-norm matrices, we derive near optimal regret bounds for online max-cut, online gambling, and online collaborative filtering. In particular, this resolves (in the af...
Optimization of immunoglobulin substitution therapy by a stochastic immune response model.
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Marc Thilo Figge
Full Text Available BACKGROUND: The immune system is a complex adaptive system of cells and molecules that are interwoven in a highly organized communication network. Primary immune deficiencies are disorders in which essential parts of the immune system are absent or do not function according to plan. X-linked agammaglobulinemia is a B-lymphocyte maturation disorder in which the production of immunoglobulin is prohibited by a genetic defect. Patients have to be put on life-long immunoglobulin substitution therapy in order to prevent recurrent and persistent opportunistic infections. METHODOLOGY: We formulate an immune response model in terms of stochastic differential equations and perform a systematic analysis of empirical therapy protocols that differ in the treatment frequency. The model accounts for the immunoglobulin reduction by natural degradation and by antigenic consumption, as well as for the periodic immunoglobulin replenishment that gives rise to an inhomogeneous distribution of immunoglobulin specificities in the shape space. Results are obtained from computer simulations and from analytical calculations within the framework of the Fokker-Planck formalism, which enables us to derive closed expressions for undetermined model parameters such as the infection clearance rate. CONCLUSIONS: We find that the critical value of the clearance rate, below which a chronic infection develops, is strongly dependent on the strength of fluctuations in the administered immunoglobulin dose per treatment and is an increasing function of the treatment frequency. The comparative analysis of therapy protocols with regard to the treatment frequency yields quantitative predictions of therapeutic relevance, where the choice of the optimal treatment frequency reveals a conflict of competing interests: In order to diminish immunomodulatory effects and to make good economic sense, therapeutic immunoglobulin levels should be kept close to physiological levels, implying high
Sánchez-Muñoz, Isabel; Granados, Rosario; Holguín Holgado, Purificación; García-Vela, José Antonio; Casares, Celia; Casares, Miguel
2015-01-01
In recent years, the reconstruction of human skin by tissue engineering represents a clinical challenge and has offered a therapeutic alternative. Avascular engineered skin equivalents have been available for several years and used to treat wounds due to burns, nonhealing ulcers, and surgical excisions. They are constituted by different types of cultured cells included in a three-dimensional structure that permits cellular proliferation to create tissue substitutes. The major drawback of these artificial skin substitutes is their lack of blood supply, since the endurance and cell proliferation of the substitute depend on an adequate oxygen and nutrient supply and on toxin removal. These functions are served by the vascular system. We have produced a new model of endothelialized skin substitute that promotes the formation of capillary-like structures by seeding human umbilical vein endothelial cells (HUVECs) with dermal fibroblasts and human adipose-derived mesenchymal stem cells (hADMSCs) in a fibrin matrix. Dermal fibroblasts and hADMSCs produce extracellular matrix that stimulates cellular growth and proliferation. hADMSCs secrete significant quantities of angiogenic and antiapoptotic factors (vascular endothelial growth factor and hepatocyte growth factor), which induce in vitro differentiation of these cells into endothelial cells promoting angiogenesis and participating in tissue repair and skin regeneration processes. We obtained the artificial skin substitute with similar structure to native skin, including dermis and epidermis. We demonstrated that endothelial cells (CD31 and von Willebrand factor positive) proliferated and organized themselves into capillary-like structures within the fibrin matrix. The epidermis showed a complete epithelization by squamous cells (AE1/AE3 cytokeratin positive) with intracytoplasmic keratohyalin granules, hyperkeratosis, and parakeratosis. We have established a novel artificial skin substitute that facilitates the formation
Matsuno, Yu-Ki; Dong, Weijie; Yokoyama, Seiya; Yonezawa, Suguru; Saito, Takuro; Gotoh, Mitsukazu; Narimatsu, Hisashi; Kameyama, Akihiko
2011-07-01
Mucins are a family of heavily glycosylated high molecular mass proteins that have great potential as novel clinical biomarkers for the diagnosis of various malignant tumors. Supported molecular matrix electrophoresis (SMME) is a new type of membrane electrophoresis that can be used to characterize mucins. In SMME, mucins migrate in a molecular matrix supported by membrane materials. Here, we have developed an immunostaining method for the identification of SMME-separated mucins. The novel method involves stably fixing the mucins onto the SMME membrane and optimizing the molecular matrix for the fixation process. We applied this technique for the detection of MUC1 produced from three cancer cell lines (T47D, HPAF-II and BxPC3) and also analyzed their O-linked glycans by mass spectrometry. Our results revealed that properties of the MUC1 molecules from the three cell lines are different in terms of migrating position in SMME and glycan profile. The present method allows simple and rapid characterization of mucins in terms of both glycans and core proteins. The method will be a useful tool for the exploration of mucin alterations associated with various diseases such as cancer.
Optimization of Triangular Matrix Functions in BLAS Library on Loongson2F
2010-01-01
International audience; BLAS (Basic Linear Algebra Subprograms) plays a very important role in scientific computing and engineering applications. ATLAS is often recommended as a way to generate an optimized BLAS library. Based on ATLAS, this paper optimizes the algorithms of triangular matrix functions on 750 MHZ Loongson 2F processor-specific architecture. Using loop unrolling, instruction scheduling and data pre-fetching techniques, computing time and memory access delay are both reduced, a...
Linearization of a Matrix Riccati Equation Associated to an Optimal Control Problem
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Foued Zitouni
2014-01-01
Full Text Available The matrix Riccati equation that must be solved to obtain the solution to stochastic optimal control problems known as LQG homing is linearized for a class of processes. The results generalize a theorem proved by Whittle and the one-dimensional case already considered by the authors. A particular two-dimensional problem is solved explicitly.
DEFF Research Database (Denmark)
Eklund, Aron Charles; Friis, Pia; Wernersson, Rasmus;
2010-01-01
DNA microarray measurements are susceptible to error caused by non-specific hybridization between a probe and a target (cross-hybridization), or between two targets (bulk-hybridization). Search algorithms such as BLASTN can quickly identify potentially hybridizing sequences. We set out to improve...
Experiments to optimize enzyme substitution therapy in pancreatic duct-ligated pigs.
Kammlott, E; Karthoff, J; Stemme, K; Gregory, P; Kamphues, J
2005-01-01
Ligation of the pancreatic duct in pigs leads to severe maldigestion and malabsorption of crude nutrients. Supplementation with 24 capsules of Creon (Solvay Pharmaceuticals GmbH, Hannover, Germany) per meal led to an increased digestibility of crude nutrients. With regard to optimization of the treatment of EPI no essential improvements can be achieved by adding omeprazol or lecithin to the diet. In pancreatic duct-ligated pigs the isolated addition of omeprazol led to an increase of the pre-caecal digestibility of crude fat and organic matter. With additional enzyme substitution, the application of omeprazol did not result in an improved fat digestibility. Isolated addition of lecithin to the diet resulted in a reduced total digestibility of crude fat. Offering the diet twice a day and using a higher frequency of enzyme applications (four or six instead of only two applications) had no effects on the digestibilty of crude fat or organic matter. According to the observations in pancreatic duct-ligated pigs, the addition of missing enzymes to the diet led to the best treatment results in EPI. Administration of omeprazol or a higher feeding frequency as well as the application of enzymes in small proportion of the whole meal or dosages given consecutively over the day showed no advantages. Furthermore, the present study suggests that the addition of lecithin cannot be recommended in EPI, when given diets with butter as the predominant fat source as in human dietetics.
Optimization of the Temperature-Time Curve for the Curing Process of Thermoset Matrix Composites
Aleksendrić, Dragan; Carlone, Pierpaolo; Ćirović, Velimir
2016-10-01
An intelligent optimization model aiming at off-line or pre-series optimization of the thermal curing cycle of polymer matrix composites is proposed and discussed. The computational procedure is based on the coupling of a finite element thermochemical process model, dynamic artificial neural networks and genetic algorithms. Objective of the optimization routine is the maximization of the composite degree of cure by the definition of the autoclave temperature. Obtained outcomes evidenced the capability of the method as well as its efficiency with respect to hard computing or experimental procedures.
Research on Optimization of Bearing Span of Main Reducer Gear System Based on the Transfer Matrix
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Huang Feng Yun
2016-01-01
Full Text Available The research object is the bearing span of the main reducer gear of the crossover vehicle for improving the performance of the Noise-Vibration-Harshness (NVH on the rear axle. It could get the optimal bearing span by modal analysis of the driving gear shaft and the vibration test of the main reducer, based on the transfer matrix. It is verified that the vibration and transmission stability are greatly improved with this optimal bearing span by the dynamic simulations of different bearing spans in ADAMS. And it can provide reference for the structural optimization design of the main reducer and the research on the vibration and noise reduction.
Hugenberg, Verena; Riemann, Burkhard; Hermann, Sven; Schober, Otmar; Schäfers, Michael; Szardenings, Katrin; Lebedev, Artem; Gangadharmath, Umesh; Kolb, Hartmuth; Walsh, Joseph; Zhang, Wei; Kopka, Klaus; Wagner, Stefan
2013-09-12
Noninvasive imaging and quantification of matrix metalloproteinase (MMP) activity in vivo are of great (pre)clinical interest. This can potentially be realized by using radiolabeled MMP inhibitors (MMPIs) as positron emission tomography (PET) imaging agents. Triazole-substituted MMPIs, discovered by our group, are highly potent inhibitors of MMP-2, -8, -9, and -13. The triazole ring and its position contribute significantly to the potency of the MMP inhibitor. To evaluate structure-activity relationships (SARs) of the initially discovered triazole-substituted MMPIs, an additional CH2-group between the backbone of the molecule and the triazole core was inserted, and the triazole ring was "inversed" by switching the alkyne and azide groups. Similar to the original triazole-substituted hydroxamates, the inverse triazole MMPIs are excellent inhibitors with promising in vivo properties. Pharmacokinetic properties and metabolic stability of an (18)F-labeled candidate in mice were investigated.
Design and optimization of a tissue-engineered bone graft substitute
Shimko, Daniel Andrew
2004-12-01
In 2000, 3.1 million surgical procedures on the musculoskeletal system were reported in the United States. For many of these cases, bone grafting was essential for successful fracture stabilization. Current techniques use intact bone obtained either from the patient (autograft) or a cadaver (allograft) to repair large defects, however, neither source is optimal. Allografts suffer integration problems, and for autografts, the tissue supply is limited. Because of these shortcomings, and the high demand for graft tissues, alternatives are being explored. To successfully engineer a bone graft replacement, one must employ a three pronged research approach, addressing (1) the cells that will inhabit the new tissue, (2) the culture environment that these cells will be exposed to, and (3) the scaffold in which these cells will reside. The work herein examines each of these three aspects in great detail. Both adult and embryonic stem cells (ESCs) were considered for the tissue-engineered bone graft. Both exhibited desirable qualities, however, neither were optimal in all categories examined. In the end, the possibility of teratoma formation and ethical issues surrounding ESCs, made the use of adult marrow-derived stem cells in the remaining experiments obligatory. In subsequent experiments, the adult stem cells' ability to form bone was optimized. Basic fibroblast growth factor, fetal bovine serum, and extracellular calcium supplementation studies were all performed. Ultimately, adult stem cells cultured in alpha-MEM supplemented with 10% fetal bovine serum, 10mM beta-glycerophosphate, 10nM dexamethasone, 50mug/ml ascorbic acid, 1%(v/v) antibiotic/antimycotic, and 10.4mM CaCl2 performed the best, producing nearly four times more mineral than any other medium formulation. Several scaffolds were then investigated including those fabricated from poly(alpha-hydroxy esters), tantalum, and poly-methylmethacrylate. In the final study, the most appealing cell type, medium
Bao, Qian; Jiang, Chenglong; Lin, Yun; Tan, Weixian; Wang, Zhirui; Hong, Wen
2016-01-01
With a short linear array configured in the cross-track direction, downward looking sparse linear array three-dimensional synthetic aperture radar (DLSLA 3-D SAR) can obtain the 3-D image of an imaging scene. To improve the cross-track resolution, sparse recovery methods have been investigated in recent years. In the compressive sensing (CS) framework, the reconstruction performance depends on the property of measurement matrix. This paper concerns the technique to optimize the measurement matrix and deal with the mismatch problem of measurement matrix caused by the off-grid scatterers. In the model of cross-track reconstruction, the measurement matrix is mainly affected by the configuration of antenna phase centers (APC), thus, two mutual coherence based criteria are proposed to optimize the configuration of APCs. On the other hand, to compensate the mismatch problem of the measurement matrix, the sparse Bayesian inference based method is introduced into the cross-track reconstruction by jointly estimate the scatterers and the off-grid error. Experiments demonstrate the performance of the proposed APCs’ configuration schemes and the proposed cross-track reconstruction method. PMID:27556471
Bao, Qian; Jiang, Chenglong; Lin, Yun; Tan, Weixian; Wang, Zhirui; Hong, Wen
2016-08-22
With a short linear array configured in the cross-track direction, downward looking sparse linear array three-dimensional synthetic aperture radar (DLSLA 3-D SAR) can obtain the 3-D image of an imaging scene. To improve the cross-track resolution, sparse recovery methods have been investigated in recent years. In the compressive sensing (CS) framework, the reconstruction performance depends on the property of measurement matrix. This paper concerns the technique to optimize the measurement matrix and deal with the mismatch problem of measurement matrix caused by the off-grid scatterers. In the model of cross-track reconstruction, the measurement matrix is mainly affected by the configuration of antenna phase centers (APC), thus, two mutual coherence based criteria are proposed to optimize the configuration of APCs. On the other hand, to compensate the mismatch problem of the measurement matrix, the sparse Bayesian inference based method is introduced into the cross-track reconstruction by jointly estimate the scatterers and the off-grid error. Experiments demonstrate the performance of the proposed APCs' configuration schemes and the proposed cross-track reconstruction method.
Directory of Open Access Journals (Sweden)
Qian Bao
2016-08-01
Full Text Available With a short linear array configured in the cross-track direction, downward looking sparse linear array three-dimensional synthetic aperture radar (DLSLA 3-D SAR can obtain the 3-D image of an imaging scene. To improve the cross-track resolution, sparse recovery methods have been investigated in recent years. In the compressive sensing (CS framework, the reconstruction performance depends on the property of measurement matrix. This paper concerns the technique to optimize the measurement matrix and deal with the mismatch problem of measurement matrix caused by the off-grid scatterers. In the model of cross-track reconstruction, the measurement matrix is mainly affected by the configuration of antenna phase centers (APC, thus, two mutual coherence based criteria are proposed to optimize the configuration of APCs. On the other hand, to compensate the mismatch problem of the measurement matrix, the sparse Bayesian inference based method is introduced into the cross-track reconstruction by jointly estimate the scatterers and the off-grid error. Experiments demonstrate the performance of the proposed APCs’ configuration schemes and the proposed cross-track reconstruction method.
Energy Technology Data Exchange (ETDEWEB)
Park, Nam-Gyu, E-mail: nkpark@knfc.co.kr [R and D Center, KEPCO Nuclear Fuel Co., LTD., 493 Deokjin-dong, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Kim, Kyoung-Joo, E-mail: kyoungjoo@knfc.co.kr [R and D Center, KEPCO Nuclear Fuel Co., LTD., 493 Deokjin-dong, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Kim, Kyoung-Hong, E-mail: kyounghong@knfc.co.kr [R and D Center, KEPCO Nuclear Fuel Co., LTD., 493 Deokjin-dong, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Suh, Jung-Min, E-mail: jmsuh@knfc.co.kr [R and D Center, KEPCO Nuclear Fuel Co., LTD., 493 Deokjin-dong, Yuseong-gu, Daejeon 305-353 (Korea, Republic of)
2013-02-15
Highlights: ► An identification method of the optimal stiffness matrix for a fuel assembly structure is discussed. ► The least squares optimization method is introduced, and a closed form solution of the problem is derived. ► The method can be expanded to the system with the limited number of modes. ► Identification error due to the perturbed mode shape matrix is analyzed. ► Verification examples show that the proposed procedure leads to a reliable solution. -- Abstract: A reactor core structural model which is used to evaluate the structural integrity of the core contains nuclear fuel assembly models. Since the reactor core consists of many nuclear fuel assemblies, the use of a refined fuel assembly model leads to a considerable amount of computing time for performing nonlinear analyses such as the prediction of seismic induced vibration behaviors. The computational time could be reduced by replacing the detailed fuel assembly model with a simplified model that has fewer degrees of freedom, but the dynamic characteristics of the detailed model must be maintained in the simplified model. Such a model based on an optimal design method is proposed in this paper. That is, when a mass matrix and a mode shape matrix are given, the optimal stiffness matrix of a discrete fuel assembly model can be estimated by applying the least squares minimization method. The verification of the method is completed by comparing test results and simulation results. This paper shows that the simplified model's dynamic behaviors are quite similar to experimental results and that the suggested method is suitable for identifying reliable mathematical model for fuel assemblies.
Energy Technology Data Exchange (ETDEWEB)
Geng, Zhen; Cui, Zhenduo [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Li, Zhaoyang, E-mail: zyli@tju.edu.cn [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China); Zhu, Shengli [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China); Liang, Yanqin [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Liu, Yunde; Li, Xue; He, Xin; Yu, Xiaoxu; Wang, Renfeng [School of Laboratory Medicine, Tianjin Medical University, Tianjin 300072 (China); Yang, Xianjin, E-mail: xjyang@tju.edu.cn [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China)
2016-01-01
Infection in primary total joint prostheses is attracting considerable attention. In this study, silver (Ag) was incorporated into hydroxyapatite (HA) using a hydrothermal method in order to improve its antimicrobial properties. Strontium (Sr) was added as a second binary element to improve the biocompatibility. The substituted HA samples were fixed on titanium (Ti) substrates by dopamine-assisted immobilization in order to evaluate their antibacterial and biological properties. The results showed that Ag and Sr were successfully incorporated into HA without affecting their crystallinity. Further, the antibacterial tests showed that all the Ag-substituted samples had good anti-bacterial properties against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Despite their good antibacterial ability, the Ag-substituted samples showed evidence of cytotoxicity on MG63 cells, characterized by low cell density and poor spreadability. The addition of Sr to the Ag-substituted samples considerably reduced the cytotoxicity of Ag. Although the viability of the cells grown on the surfaces of co-substituted HA was not as high as that of the cells grown on the HA surfaces, it is believed that excellent antibacterial properties and good biological activity can be achieved by balancing the dosage of Sr and Ag. - Highlights: • Ag- and Sr-substituted HA was prepared by hydrothermal method. • Ag- and Sr-substituted HA coating was deposited on dopamine functionalized titanium. • Ag-substituted HA biofilm showed a remarkable antibacterial activity. • Sr could offset the side effects of Ag.
Implementation of IMDCT Block of an MP3 Decoder through Optimization on the DCT Matrix
Directory of Open Access Journals (Sweden)
M. Galabov
2004-12-01
Full Text Available The paper describes an attempt to create an efficient dedicatedMP3-decoder, according to the MPEG-1 Layer III standard. A new methodof Inverse Modified Discrete Cosine Transform by optimization on theDiscrete Cosine Transform (DCT matrix is proposed and an assemblerprogram for Digital Signal Processor is developed. In addition, aprogram to calculate DCT using Lee's algorithm for any matrix of thesize 2M is created. The experimental results have proven that thedecoder is able to stream and decode MP3 in real time.
Maiorana, Carlo; Beretta, Mario; Pivetti, Luca; Stoffella, Enrico; Grossi, Giovanni B.; Herford, Alan S.
2016-01-01
Background: The presence of keratinized tissue around dental implants is more than desirable either from a functional and aesthetic point of view, making soft tissue grafting a common practice in implant rehabilitation. Autogenous soft tissue grafting procedures are usually associated with high morbidity. Aim of this study was to assess the efficacy of a xenogeneic collagen matrix as a substitute for soft tissue grafting around dental implants. Methods: 15 consecutive patients underwent a vestibuloplasty and grafting, both in the mandible and the maxilla, with a collagen matrix. Results: The primary endpoint was to evaluate the resorption of the graft along with the re-epithelization grafted area. The percentage of the resorption was 44,4%, with a mean gain in vestibular height of 3 mm. Secondary endpoints evaluated the clinical appearance, the hemostatic effect and the post-operative pain. All subjects referred minimal pain with no bleeding. No adverse reaction nor infection were noted. Conclusion: This study showed that the used collagen matrix can find major interest in those patients who need a greater aesthetic outcome as the matrix has a perfect integration with the surrounding tissues. Furthermore it is strongly recommended for those patients who can bear little pain. Clinical Significance: Post-operative morbidity of autologous grafts is the biggest concern of this type of surgery. The possibility to use a soft tissue substitute is a great achievement as morbidity decreases and bigger areas can be treated in a single surgery. The present study showed the efficacy of a collagen matrix as this kind of substitute. PMID:27583050
Directory of Open Access Journals (Sweden)
Jian Cheng
2014-01-01
Full Text Available A key component in the molten carbonate fuel cell (MCFC is electrolyte matrix, which provides both ionic conduction and gas sealing. The aim of this work is to investigate the effects of selected operating conditions on the performance of the matrix preparation. Slurries were prepared to produce matrices by the technique of tape casting. The characteristics of the slurries and matrices were examined by laser particle size analyzer, scanning electron microscopy, and BET surface area analyzer. The testing results revealed that a slurry composition with 40 wt.% lithium aluminate was the optimal formulation to produce a good matrix with a pore size distribution of 0.1–0.4 μm and porosity of 50 vol.%. Coarse and fine LiAlO2 particles were added in the matrix slurry to enhance the mechanical strength. Several green sheets were heated and pressed to enhance the bulk density to get a dense matrix of MCFC. Finally, a single MCFC was assembled and tested. The testing results showed the matrix with 40% solid loading gave the maximum discharge current of 20 A at 0.56 V.
Directory of Open Access Journals (Sweden)
John Anish K.
2017-01-01
Full Text Available Matrix Heat Exchanger is having wide spread applications in cryogenics and aerospace, where high effectiveness and compactness is essential. This can be achieved by providing high thermal conductive plates and low thermal conductive spacers alternately. These perforated plate matrix heat exchangers have near to 100% efficiency due to low longitudinal heat transfer. The heat transfer and flow friction characteristics of a perforated plate matrix heat exchanger can be represented using Colburn factor and friction factor. In this paper, dimensionless parameters like Reynolds number (Re, porosity (p, perforation perimeter factor (P f, plate thickness to pore diameter ratio (l/d and spacer thickness to plate thickness ratio (s/l have been optimized for maximum Colburn factor and minimum friction factor using genetic algorithm. Two algorithms, one for single objective and the other for multi-objective problems, which are believed to be more efficient, are described. The algorithms coded with MATLAB, is used to perform multi-objective optimization on perforated plate matrix heat exchanger surfaces. The results show promising results.
Moritz, Gerrit; Hess, Bernd Artur; Reiher, Markus
2005-01-08
The density-matrix renormalization group algorithm has emerged as a promising new method in ab initio quantum chemistry. However, many problems still need to be solved before this method can be applied routinely. At the start of such a calculation, the orbitals originating from a preceding quantum chemical calculation must be placed in a specific order on a one-dimensional lattice. This ordering affects the convergence of the density-matrix renormalization group iterations significantly. In this paper, we present two approaches to obtain optimized orderings of the orbitals. First, we use a genetic algorithm to optimize the ordering with respect to a low total electronic energy obtained at a predefined stage of the density-matrix renormalization group algorithm with a given number of total states kept. In addition to that, we derive orderings from the one- and two-electron integrals of our test system. This test molecule is the chromium dimer, which is known to possess a complicated electronic structure. For this molecule, we have carried out calculations for the various orbital orderings obtained. The convergence behavior of the density-matrix renormalization group iterations is discussed in detail.
Directory of Open Access Journals (Sweden)
Wang Wen-qin
2015-02-01
Full Text Available The waveforms used in Multiple-Input Multiple-Output (MIMO Synthetic Aperture Radar (SAR should have a large time-bandwidth product and good ambiguity function performance. A scheme to design multiple orthogonal MIMO SAR Orthogonal Frequency Division Multiplexing (OFDM chirp waveforms by combinational sparse matrix and correlation optimization is proposed. First, the problem of MIMO SAR waveform design amounts to the associated design of hopping frequency and amplitudes. Then a iterative exhaustive search algorithm is adopted to optimally design the code matrix with the constraints minimizing the block correlation coefficient of sparse matrix and the sum of cross-correlation peaks. And the amplitudes matrix are adaptively designed by minimizing the cross-correlation peaks with the genetic algorithm. Additionally, the impacts of waveform number, hopping frequency interval and selectable frequency index are also analyzed. The simulation results verify the proposed scheme can design multiple orthogonal large time-bandwidth product OFDM chirp waveforms with low cross-correlation peak and sidelobes and it improves ambiguity performance.
Institute of Scientific and Technical Information of China (English)
GAO Zhen-xing; ZHANG Shi-tao; SUN Xiao-ling
2009-01-01
In this paper, the discrete mean-variance model is considered for portfolio selection under concave transaction costs. By using the Cholesky decomposition technique, the convariance matrix to obtain a separable mixed integer nonlinear optimization problem is decomposed. A brand-and-bound algorithm based on Lagrangian relaxation is then proposed. Com-putational results are reported for test problems with the data randomly generated and those from the US stock market.
KBLAS: An Optimized Library for Dense Matrix-Vector Multiplication on GPU Accelerators
Abdelfattah, Ahmad
2016-05-11
KBLAS is an open-source, high-performance library that provides optimized kernels for a subset of Level 2 BLAS functionalities on CUDA-enabled GPUs. Since performance of dense matrix-vector multiplication is hindered by the overhead of memory accesses, a double-buffering optimization technique is employed to overlap data motion with computation. After identifying a proper set of tuning parameters, KBLAS efficiently runs on various GPU architectures while avoiding code rewriting and retaining compliance with the standard BLAS API. Another optimization technique allows ensuring coalesced memory access when dealing with submatrices, especially for high-level dense linear algebra algorithms. All KBLAS kernels have been leveraged to a multi-GPU environment, which requires the introduction of new APIs. Considering general matrices, KBLAS is very competitive with existing state-of-the-art kernels and provides a smoother performance across a wide range of matrix dimensions. Considering symmetric and Hermitian matrices, the KBLAS performance outperforms existing state-of-the-art implementations on all matrix sizes and achieves asymptotically up to 50% and 60% speedup against the best competitor on single GPU and multi-GPUs systems, respectively. Performance results also validate our performance model. A subset of KBLAS highperformance kernels have been integrated into NVIDIA\\'s standard BLAS implementation (cuBLAS) for larger dissemination, starting from version 6.0. © 2016 ACM.
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
A real n × n symmetric matrix X = (xij)n×n is called a bisymmetric matrix if xij = xn+1-j,n+1-i. Based on the projection theorem, the canonical correlation decomposition and the generalized singular value decomposition, a method useful for finding the least-squares solutions of the matrix equation ATXA = B over bisymmetric matrices is proposed. The expression of the least-squares solutions is given. Moreover, in the corresponding solution set, the optimal approximate solution to a given matrix is also derived. A numerical algorithm for finding the optimal approximate solution is also described.
Hao, Ge-Fei; Yang, Sheng-Gang; Huang, Wei; Wang, Le; Shen, Yan-Qing; Tu, Wen-Long; Li, Hui; Huang, Li-Shar; Wu, Jia-Wei; Berry, Edward A.; Yang, Guang-Fu
2015-01-01
Hit to lead (H2L) optimization is a key step for drug and agrochemical discovery. A critical challenge for H2L optimization is the low efficiency due to the lack of predictive method with high accuracy. We described a new computational method called Computational Substitution Optimization (CSO) that has allowed us to rapidly identify compounds with cytochrome bc1 complex inhibitory activity in the nanomolar and subnanomolar range. The comprehensively optimized candidate has proved to be a slow binding inhibitor of bc1 complex, ~73-fold more potent (Ki = 4.1 nM) than the best commercial fungicide azoxystrobin (AZ; Ki = 297.6 nM) and shows excellent in vivo fungicidal activity against downy mildew and powdery mildew disease. The excellent correlation between experimental and calculated binding free-energy shifts together with further crystallographic analysis confirmed the prediction accuracy of CSO method. To the best of our knowledge, CSO is a new computational approach to substitution-scanning mutagenesis of ligand and could be used as a general strategy of H2L optimisation in drug and agrochemical design.
Mattioda, A. L.; Hudgins, D. M.; Bauschlicher, C. W., Jr.; Allamandola, L. J.
2004-01-01
The matrix-isolation technique has been employed to measure the mid-infrared spectra of phenazine (C12H8N2), a dual substituted Polycyclic Aromatic Nitrogen Heterocycle (PANH), in the neutral, cationic and anionic forms. The experimentally measured band frequencies and intensities are tabulated and compared with their calculated values as well as those of the non-substituted parent molecule, anthracene. The theoretical band positions and intensities were calculated using both the 3-31 G as well as the larger 6-3lG* Basis Sets. A comparison of the results can be found in the tables. The spectroscopic properties of phenazine and its cation are similar to those observed in mono-substituted PANHs, with one exception. The presence of a second nitrogen atom results in an additional enhancement of the cation's total integrated intensity, for the 1500-1000 cm(sup -1) (6.7 to 10 micron) region, over that observed for a mono-substituted PANH cation. The significance of this enhancement and the astrobiological implications of these results are discussed.
Geng, Zhen; Cui, Zhenduo; Li, Zhaoyang; Zhu, Shengli; Liang, Yanqin; Liu, Yunde; Li, Xue; He, Xin; Yu, Xiaoxu; Wang, Renfeng; Yang, Xianjin
2016-01-01
Infection in primary total joint prostheses is attracting considerable attention. In this study, silver (Ag) was incorporated into hydroxyapatite (HA) using a hydrothermal method in order to improve its antimicrobial properties. Strontium (Sr) was added as a second binary element to improve the biocompatibility. The substituted HA samples were fixed on titanium (Ti) substrates by dopamine-assisted immobilization in order to evaluate their antibacterial and biological properties. The results showed that Ag and Sr were successfully incorporated into HA without affecting their crystallinity. Further, the antibacterial tests showed that all the Ag-substituted samples had good anti-bacterial properties against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Despite their good antibacterial ability, the Ag-substituted samples showed evidence of cytotoxicity on MG63 cells, characterized by low cell density and poor spreadability. The addition of Sr to the Ag-substituted samples considerably reduced the cytotoxicity of Ag. Although the viability of the cells grown on the surfaces of co-substituted HA was not as high as that of the cells grown on the HA surfaces, it is believed that excellent antibacterial properties and good biological activity can be achieved by balancing the dosage of Sr and Ag.
Directory of Open Access Journals (Sweden)
Xifan Yao
2016-01-01
Full Text Available To improve the solution efficiency and reliability of multidisciplinary design optimization (MDO, an enhanced MDO approach, called sequenced collaborative optimization (SCO, is proposed. The proposed approach introduces the design structure matrix (DSM to describe the coupling effects among disciplines and aggregates those mutually coupling disciplines into the strong tie groups among similar ones and the weak tie among heterogeneous ones through clustering algorithms. Further, those in the same group are sequenced by the DSM division algorithm. Moreover, by adding constraints, the groups are made independent, resulting in a tree structure without loops, thus decoupling the original multidisciplinary problem into several independent collaborative optimization modules. In the end, an example is employed to verify the efficiency and reliability of the approach.
Carja, Gabriela; Nakajima, Akira; Dranca, Cristian; Okada, Kiyoshi
2010-10-01
A room temperature nanocarving strategy is developed for the fabrication of nanoparticles of nickel oxide on zinc-substituted anionic clay matrix (Ni/ZnLDH). It is based on the growth and organization of nanoparticles of nickel oxide which occur during the structural reconstruction of the layered structure of the anionic clay in NiSO4 aqueous solution. No organic compounds are used during the fabrication. The described material was characterized by X-ray diffraction (XRD), IR spectroscopy (FTIR), transmission electron microscopy (TEM), field-emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Results show that the nickel-clay nanoarchitecture consists of small nanoparticles of nickel oxide (average size 7 nm) deposited on the larger nanoparticles (average size 90 nm) of zinc-substituted clay. The optical properties of the new nickel-zinc formulation are studied by UV-Vis.
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Qiaorui Si
2013-01-01
Full Text Available The implementation of energy-saving and emission-reduction techniques has become a worldwide consensus. Thus, special attention should be provided to the field of pump optimization. With the objective of focusing on multiobjective optimization problems in low-specific-speed pumps, 10 parameters were carefully selected in this study for an L27(310 orthogonal experiment. The parameters include the outlet width of the impeller blade, blade number, and inlet setting angle of the guide vane. The numerical calculation appropriate for forecasting the performance of multistage pumps, such as the head, efficiency, and shaft power, was analyzed. Results were obtained after calculating the two-stage flow field of the pump through computational fluid dynamics (CFD methods. A matrix method was proposed to optimize the results of the orthographic experiment. The optimal plan was selected according to the weight of each factor. Calculated results indicate that the inlet setting angle of the guide vane influences efficiency significantly and that the outlet angle of blades has an effect on the head and shaft power. A prototype was produced with the optimal plan for testing. The efficiency rating of the prototype reached 58.61%; maximum shaft power was within the design requirements, which verifies that the proposed method is feasible for pump optimization.
Tian, Zhen; Jia, Xun; Jiang, Steve B
2013-01-01
In the treatment plan optimization for intensity modulated radiation therapy (IMRT), dose-deposition coefficient (DDC) matrix is often pre-computed to parameterize the dose contribution to each voxel in the volume of interest from each beamlet of unit intensity. However, due to the limitation of computer memory and the requirement on computational efficiency, in practice matrix elements of small values are usually truncated, which inevitably compromises the quality of the resulting plan. A fixed-point iteration scheme has been applied in IMRT optimization to solve this problem, which has been reported to be effective and efficient based on the observations of the numerical experiments. In this paper, we aim to point out the mathematics behind this scheme and to answer the following three questions: 1) whether the fixed-point iteration algorithm converges or not? 2) when it converges, whether the fixed point solution is same as the original solution obtained with the complete DDC matrix? 3) if not the same, wh...
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Ashwini R. Madgulkar
2013-01-01
Full Text Available The aim was to determine the release-modifying effect of carboxymethyl xyloglucan for oral drug delivery. Sustained release matrix tablets of tramadol HCl were prepared by wet granulation method using carboxymethyl xyloglucan as matrix forming polymer. HPMC K100M was used in a small amount to control the burst effect which is most commonly seen with natural hydrophilic polymers. A simplex centroid design with three independent variables and two dependent variables was employed to systematically optimize drug release profile. Carboxymethyl xyloglucan , HPMC K100M , and dicalcium phosphate were taken as independent variables. The dependent variables selected were percent of drug release at 2nd hour and at 8th hour . Response surface plots were developed, and optimum formulations were selected on the basis of desirability. The formulated tablets showed anomalous release mechanism and followed matrix drug release kinetics, resulting in regulated and complete release from the tablets within 8 to 10 hours. The polymer carboxymethyl xyloglucan and HPMC K100M had significant effect on drug release from the tablet (. Polynomial mathematical models, generated for various response variables using multiple regression analysis, were found to be statistically significant (. The statistical models developed for optimization were found to be valid.
Wang, Yuhao; Li, Xin; Xu, Kai; Ren, Fengbo; Yu, Hao
2017-04-01
Compressive sensing is widely used in biomedical applications, and the sampling matrix plays a critical role on both quality and power consumption of signal acquisition. It projects a high-dimensional vector of data into a low-dimensional subspace by matrix-vector multiplication. An optimal sampling matrix can ensure accurate data reconstruction and/or high compression ratio. Most existing optimization methods can only produce real-valued embedding matrices that result in large energy consumption during data acquisition. In this paper, we propose an efficient method that finds an optimal Boolean sampling matrix in order to reduce the energy consumption. Compared to random Boolean embedding, our data-driven Boolean sampling matrix can improve the image recovery quality by 9 dB. Moreover, in terms of sampling hardware complexity, it reduces the energy consumption by 4.6× and the silicon area by 1.9× over the data-driven real-valued embedding.
Ghanbari, F.; Arab, A.; Shishe Bor, M.; Mardaneh, M. R.
2017-04-01
La/Ni-substituted strontium hexaferrite Sr0.8La0.2Ni x Fe12- x O19 ( x = 0.2 to 1.0 in steps of 0.2) nanoparticles have been produced by a coprecipitation method at reaction and calcination temperature of 80°C and 1200°C, respectively. X-ray diffraction (XRD) analysis confirmed formation of single-phase M-type hexaferrite structure. The average crystallite size and morphology of the nanoparticles were obtained from XRD analysis and transmission electron microscopy (TEM), respectively. The magnetic properties in magnetic field of 12 kOe obtained from room-temperature hysteresis loops revealed minimum and maximum magnetization for x = 0.4 and 0.8, respectively, a behavior attributed to the ionic radii of the substituted cations, canted spin structure, electron hopping between cations, and the substitutional sites of the ions. It was also confirmed that the magnetization of nanoscale particles was lower than that of bulk material, which can be explained based on the different behavior of surface versus bulk atoms. The coercivity varied with x in a similar way to the magnetization, being related to sample anisotropy. In the M-type hexaferrite structure, substitution of Fe3+ by Ni2+ occurred at octahedral sites, making the greatest contribution to the anisotropy.
Samuely, Tomas; Liu, Shi-Xia; Wintjes, Nikolai; Haas, Marco; Decurtins, Silvio; Jung, Thomas A.; Stoehr, Meike
2008-01-01
Symmetrically substituted phthalocyanines (Pcs) with eight peripheral di-(tert-butyl)phenoxy (DTPO) groups self-organize on Ag(111) and Au(111) substrates into various assembly structures. These different structural phases were studied by scanning tunneling microscopy (STM). On the basis of
Optimal Design of FPGA Switch Matrix with Ion Mobility Based Nonvolatile ReRAM
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Peng Hai-yun
2015-01-01
Full Text Available There are high demands for research of new device with greater accessing speed and stability to replace the current SRAM storage cell. The resistive random access memory (ReRAM is a metal oxide which is based on nonvolatile memory device possessing the characteristics of high read/write speed, high storage density, low power, low cost, very small cell, being nonvolatile, and unlimited writing endurance. The device has extreme short erasing time and the stored charge cannot be destroyed after power-off. Therefore, the ReRAM device is a significant storage device for many applications in the next generation. In this paper, we first explored the mechanism of the ReRAM device based on ion mobility model and then applied this device to optimize the design of FPGA switching matrix. The results show that it is beneficial to enhance the FPGA performance to replace traditional SRAM cells with ReRAM cells for the switching matrix.
OPTIMAL TIME FOR SUBSTITUTION OF Eucalyptus spp POPULATIONS – THE CASE OF CONSTANT TECHNOLOGY
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Álvaro Nogueira de Souza1;
2001-01-01
Full Text Available The few studies on renewal of Eucalyptus spp populations done in Brazil consider constant technology. This is done this way for facilitating the modeling of how variables affect this activity, such as income, costs, rates of discount and yield. The reason for not considering the gains earned through technological progress is the lack of a specific dynamic model. This study was carried out aiming to get to know the forest rotation with values from the sixties (beginning of tax exemption programme and current values (nineties aiming to obtain wood for cellulose and charcoal production; to determine the moment of substitution of a population which presents the same yield and the same cost structure through time as well as to determine how many cuttings should be done until the final cycle; to determine how many cuttings should be done until substitution (substitution chain; to verify the sensitivity of the substitution time to variations in the discount rates, wood prices, yield, land costs, harvesting costs and coppice yield. The results were tested in a case study, employing the Gompertz Function to determine the population yield. The Current Net Value Method was used as a crieterion of economic decision. It has been concluded that: The forest rotation to produce charcoal in the sixties was at 13 years of age; the current rotation is at 7 years of age; the final cycle allows up to 13 cuttings, but considering the possibility of land leasing, the best alternative is to conduce the sproutings up to the third cutting; an increase in factors such as discount rates, wood prices and yield caused reduction of the cutting age; increase in land costs did not affect the cutting ages; increase in the logging cost increased the cutting ages; the substitution of population now a days happens after 3 cuttings, while in the sixties it happened after 2 cuttings due to the lesser loss; an increase in factors such as discount rates, wood prices, logging costs and
Choi, Du Hyung; Shin, Sangmun; Khoa Viet Truong, Nguyen; Jeong, Seong Hoon
2012-09-01
A robust experimental design method was developed with the well-established response surface methodology and time series modeling to facilitate the formulation development process with magnesium stearate incorporated into hydrophilic matrix tablets. Two directional analyses and a time-oriented model were utilized to optimize the experimental responses. Evaluations of tablet gelation and drug release were conducted with two factors x₁ and x₂: one was a formulation factor (the amount of magnesium stearate) and the other was a processing factor (mixing time), respectively. Moreover, different batch sizes (100 and 500 tablet batches) were also evaluated to investigate an effect of batch size. The selected input control factors were arranged in a mixture simplex lattice design with 13 experimental runs. The obtained optimal settings of magnesium stearate for gelation were 0.46 g, 2.76 min (mixing time) for a 100 tablet batch and 1.54 g, 6.51 min for a 500 tablet batch. The optimal settings for drug release were 0.33 g, 7.99 min for a 100 tablet batch and 1.54 g, 6.51 min for a 500 tablet batch. The exact ratio and mixing time of magnesium stearate could be formulated according to the resulting hydrophilic matrix tablet properties. The newly designed experimental method provided very useful information for characterizing significant factors and hence to obtain optimum formulations allowing for a systematic and reliable experimental design method.
DEFF Research Database (Denmark)
Andersen, Stig Kildegård; Carlsen, Henrik; Thomsen, Per Grove
2006-01-01
A new regenerator matrix design that improves the efficiency of a Stirling engine has been developed in a numerical study of the existing SM5 Stirling engine. A new, detailed, one-dimensional Stirling engine model that delivers results in good agreement with experimental data was used for mapping...... the per- formance of the engine, for mapping the effects of regenerator matrix temperature oscillations, and for optimising the regenerator design. The regenerator matrix temperatures were found to oscillate in two modes. The first mode was oscillation of a nearly linear axial matrix temperature profile...... while the second mode bended the ends of the axial matrix temperature profile when gas flowed into the regenerator with a temperature significantly different from the matrix temperature. The first mode of oscillation improved the efficiency of the engine but the second mode reduced both the work output...
Optimization on microlattice materials for sound absorption by an integrated transfer matrix method.
Cai, Xiaobing; Yang, Jun; Hu, Gengkai
2015-04-01
Materials with well-defined microlattice structures are superlight, stable, and thus bear great potential in sound absorption. An integrated transfer matrix method (TMM) is proposed to evaluate the sound absorbing efficiency of these lattice materials, in which a massive number of micropores are densely placed. A comparison between integrated TMM and conventional TMM reveals that the proposed approach offers better predictions on sound absorption of microlattice. This approach is then employed to optimize the microlattice material to determine the best pore and porosity that lead to maximum absorbing efficiency capability and minimum required thickness to attain a target sound absorption.
Hu, Weifeng
2015-01-01
We describe and extend the formalism of state-specific analytic density matrix renormalization group (DMRG) energy gradients, first used by Liu et al (J. Chem. Theor.Comput. 9, 4462 (2013)). We introduce a DMRG wavefunction maximum overlap following technique to facilitate state-specific DMRG excited state optimization. Using DMRG configuration interaction (DMRG-CI) gradients we relax the low-lying singlet states of a series of trans-polyenes up to C20H22. Using the relaxed excited state geometries as well as correlation functions, we elucidate the exciton, soliton, and bimagnon ("single-fission") character of the excited states, and find evidence for a planar conical intersection.
Strömberg, Eric A; Nyberg, Joakim; Hooker, Andrew C
2016-12-01
With the increasing popularity of optimal design in drug development it is important to understand how the approximations and implementations of the Fisher information matrix (FIM) affect the resulting optimal designs. The aim of this work was to investigate the impact on design performance when using two common approximations to the population model and the full or block-diagonal FIM implementations for optimization of sampling points. Sampling schedules for two example experiments based on population models were optimized using the FO and FOCE approximations and the full and block-diagonal FIM implementations. The number of support points was compared between the designs for each example experiment. The performance of these designs based on simulation/estimations was investigated by computing bias of the parameters as well as through the use of an empirical D-criterion confidence interval. Simulations were performed when the design was computed with the true parameter values as well as with misspecified parameter values. The FOCE approximation and the Full FIM implementation yielded designs with more support points and less clustering of sample points than designs optimized with the FO approximation and the block-diagonal implementation. The D-criterion confidence intervals showed no performance differences between the full and block diagonal FIM optimal designs when assuming true parameter values. However, the FO approximated block-reduced FIM designs had higher bias than the other designs. When assuming parameter misspecification in the design evaluation, the FO Full FIM optimal design was superior to the FO block-diagonal FIM design in both of the examples.
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Prokhin Egor Anatol’evich
2016-10-01
Full Text Available In the modern conditions innovatization of construction is of great necessity, though it is associated with a number of problems of first of all institutional genesis. The development of green construction in Russia is on its first stages, though its necessity is growing according to the tendency for energy efficiency and sustainable development. The innovative process of ecological construction has a network model and requires its optimization with the aim of further development by advancing the institutional platform. The author proposed a conceptual scheme for an institutional platform of the innovative process of green construction and conducted systematization of institutional structures. The unique role of innovative and ecological institutes is substantiated. The author recommends an optimization method for institutional interaction of the subjects using the stakeholder theory and the theory of matrix games aimed at activation of innovative green technologies. Practical application of the offered algorithms and methods will allow increasing the efficiency of green construction development.
Ghosh, Debashree; Hachmann, Johannes; Yanai, Takeshi; Chan, Garnet Kin-Lic
2008-04-01
In previous work we have shown that the density matrix renormalization group (DMRG) enables near-exact calculations in active spaces much larger than are possible with traditional complete active space algorithms. Here, we implement orbital optimization with the DMRG to further allow the self-consistent improvement of the active orbitals, as is done in the complete active space self-consistent field (CASSCF) method. We use our resulting DMRG-CASSCF method to study the low-lying excited states of the all-trans polyenes up to C24H26 as well as β-carotene, correlating with near-exact accuracy the optimized complete π-valence space with up to 24 active electrons and orbitals, and analyze our results in the light of the recent discovery from resonance Raman experiments of new optically dark states in the spectrum.
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In-Suck Baek
2014-11-01
Full Text Available A multi-spectral fluorescence imaging technique was used to detect defective cherry tomatoes. The fluorescence excitation and emission matrix was used to measure for defects, sound surface and stem areas to determine the optimal fluorescence excitation and emission wavelengths for discrimination. Two-way ANOVA revealed the optimal excitation wavelength for detecting defect areas was 410 nm. Principal component analysis (PCA was applied to the fluorescence emission spectra of all regions at 410 nm excitation to determine the emission wavelengths for defect detection. The major emission wavelengths were 688 nm and 506 nm for the detection. Fluorescence images combined with the determined emission wavebands demonstrated the feasibility of detecting defective cherry tomatoes with >98% accuracy. Multi-spectral fluorescence imaging has potential utility in non-destructive quality sorting of cherry tomatoes.
Energy Technology Data Exchange (ETDEWEB)
Andersen, Stig Kildegard [Department of Mechanical Engineering, Energy Engineering Section, Technical University of Denmark, Nils Koppels Alle bygning 402, DK-2800 Kgs. Lyngby (Denmark)]. E-mail: ska@mek.dtu.dk; Carlsen, Henrik [Department of Mechanical Engineering, Energy Engineering Section, Technical University of Denmark, Nils Koppels Alle bygning 402, DK-2800 Kgs. Lyngby (Denmark); Thomsen, Per Grove [Informatics and Mathematical Modelling, Technical University of Denmark, Richard Petersens Plads bygning, DK-2800 Kgs. Lyngby (Denmark)
2006-05-15
A new regenerator matrix design that improves the efficiency of a Stirling engine has been developed in a numerical study of the existing SM5 Stirling engine. A new, detailed, one-dimensional Stirling engine model that delivers results in good agreement with experimental data was used for mapping the performance of the engine, for mapping the effects of regenerator matrix temperature oscillations, and for optimising the regenerator design. The regenerator matrix temperatures were found to oscillate in two modes. The first mode was oscillation of a nearly linear axial matrix temperature profile while the second mode bended the ends of the axial matrix temperature profile when gas flowed into the regenerator with a temperature significantly different from the matrix temperature. The first mode of oscillation improved the efficiency of the engine but the second mode reduced both the work output and efficiency of the engine. A new regenerator with three differently designed matrix sections that amplified the first mode of oscillation and reduced the second improved the efficiency of the engine from the current 32.9 to 33.2% with a 3% decrease in power output. An efficiency of 33.0% was achievable with uniform regenerator matrix properties.
Energy Technology Data Exchange (ETDEWEB)
Ghanaati, Shahram; Orth, Carina; Barbeck, Mike; Kirkpatrick, Charles James [Institute of Pathology, University Medical Center of the Johannes Gutenberg University Mainz, Langenbeckstrasse 1, 55101 Mainz (Germany); Willershausen, Ines [Institute for Dental Material Sciences and Technology, University Medical Center of the Johannes Gutenberg University Mainz, Anselm-Franz-von-Bentzel-Weg 14, 55128 Mainz (Germany); Thimm, Benjamin W [Institute for Biomechanics, ETH Zuerich, Wolfgang-Pauli-Str.10, 8093 Zuerich (Switzerland); Booms, Patrick [Leeds Institute of Molecular Medicine, Section of Medicine, Surgery and Anaesthesia, University of Leeds (United Kingdom); Stuebinger, Stefan; Landes, Constantin; Sader, Robert Anton, E-mail: ghanaati@uni-mainz.d [Department for Oral, Cranio-Maxillofacial and Facial Plastic Surgery, Medical Center of the Goethe University Frankfurt, Theodor-Stein-Kai 7, 60596 Frankfurt am Main (Germany)
2010-06-01
The clinical suitability of a bone substitute material is determined by the ability to induce a tissue reaction specific to its composition. The aim of this in vivo study was to analyze the tissue reaction to a silica matrix-embedded, nanocrystalline hydroxyapatite bone substitute. The subcutaneous implantation model in Wistar rats was chosen to assess the effect of silica degradation on the vascularization of the biomaterial and its biodegradation within a time period of 6 months. Already at day 10 after implantation, histomorphometrical analysis showed that the vascularization of the implantation bed reached its peak value compared to all other time points. Both vessel density and vascularization significantly decreased until day 90 after implantation. In this time period, the bone substitute underwent a significant degradation initiated by TRAP-positive and TRAP-negative multinucleated giant cells together with macrophages and lymphocytes. Although no specific tissue reaction could be related to the described silica degradation, the biomaterial was close to being fully degraded without a severe inflammatory response. These characteristics are advantageous for bone regeneration and remodeling processes.
Ahrari, Ali; Deb, Kalyanmoy; Preuss, Mike
2017-01-01
During the recent decades, many niching methods have been proposed and empirically verified on some available test problems. They often rely on some particular assumptions associated with the distribution, shape, and size of the basins, which can seldom be made in practical optimization problems. This study utilizes several existing concepts and techniques, such as taboo points, normalized Mahalanobis distance, and the Ursem's hill-valley function in order to develop a new tool for multimodal optimization, which does not make any of these assumptions. In the proposed method, several subpopulations explore the search space in parallel. Offspring of a subpopulation are forced to maintain a sufficient distance to the center of fitter subpopulations and the previously identified basins, which are marked as taboo points. The taboo points repel the subpopulation to prevent convergence to the same basin. A strategy to update the repelling power of the taboo points is proposed to address the challenge of basins of dissimilar size. The local shape of a basin is also approximated by the distribution of the subpopulation members converging to that basin. The proposed niching strategy is incorporated into the covariance matrix self-adaptation evolution strategy (CMSA-ES), a potent global optimization method. The resultant method, called the covariance matrix self-adaptation with repelling subpopulations (RS-CMSA), is assessed and compared to several state-of-the-art niching methods on a standard test suite for multimodal optimization. An organized procedure for parameter setting is followed which assumes a rough estimation of the desired/expected number of minima available. Performance sensitivity to the accuracy of this estimation is also studied by introducing the concept of robust mean peak ratio. Based on the numerical results using the available and the introduced performance measures, RS-CMSA emerges as the most successful method when robustness and efficiency are
Matrix Completion Optimization for Localization in Wireless Sensor Networks for Intelligent IoT
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Thu L. N. Nguyen
2016-05-01
Full Text Available Localization in wireless sensor networks (WSNs is one of the primary functions of the intelligent Internet of Things (IoT that offers automatically discoverable services, while the localization accuracy is a key issue to evaluate the quality of those services. In this paper, we develop a framework to solve the Euclidean distance matrix completion problem, which is an important technical problem for distance-based localization in WSNs. The sensor network localization problem is described as a low-rank dimensional Euclidean distance completion problem with known nodes. The task is to find the sensor locations through recovery of missing entries of a squared distance matrix when the dimension of the data is small compared to the number of data points. We solve a relaxation optimization problem using a modification of Newton’s method, where the cost function depends on the squared distance matrix. The solution obtained in our scheme achieves a lower complexity and can perform better if we use it as an initial guess for an interactive local search of other higher precision localization scheme. Simulation results show the effectiveness of our approach.
Matrix Completion Optimization for Localization in Wireless Sensor Networks for Intelligent IoT.
Nguyen, Thu L N; Shin, Yoan
2016-05-18
Localization in wireless sensor networks (WSNs) is one of the primary functions of the intelligent Internet of Things (IoT) that offers automatically discoverable services, while the localization accuracy is a key issue to evaluate the quality of those services. In this paper, we develop a framework to solve the Euclidean distance matrix completion problem, which is an important technical problem for distance-based localization in WSNs. The sensor network localization problem is described as a low-rank dimensional Euclidean distance completion problem with known nodes. The task is to find the sensor locations through recovery of missing entries of a squared distance matrix when the dimension of the data is small compared to the number of data points. We solve a relaxation optimization problem using a modification of Newton's method, where the cost function depends on the squared distance matrix. The solution obtained in our scheme achieves a lower complexity and can perform better if we use it as an initial guess for an interactive local search of other higher precision localization scheme. Simulation results show the effectiveness of our approach.
Nuclear norm penalization and optimal rates for noisy low rank matrix completion
Koltchinskii, Vladimir; Lounici, Karim
2010-01-01
This paper deals with the trace regression model where $n$ entries or linear combinations of entries of an unknown $m_1\\times m_2$ matrix $A_0$ corrupted by noise are observed. We propose a new nuclear norm penalized estimator of $A_0$ and establish a general sharp oracle inequality for this estimator for arbitrary values of $n,m_1,m_2$ under the condition of isometry in expectation. Then this method is applied to the matrix completion problem. In this case, the estimator admits a simple explicit form and we prove that it satisfies oracle inequalities with faster rates of convergence than in the previous works. They are valid, in particular, in the high-dimensional setting $m_1m_2\\gg n$. We show that the obtained rates are optimal up to logarithmic factors in a minimax sense and also derive, for any fixed matrix $A_0$, a non-minimax lower bound on the rate of convergence of our estimator, which coincides with the upper bound up to a constant factor. Finally, we show that our procedure provides an exact recove...
Institute of Scientific and Technical Information of China (English)
Liu Weidong; Zhu Hua; Wang Yiping; Zhou Shengqiang; Bai Yalei; Zhao Chunsheng
2013-01-01
Non-dominated sorting genetic algorithm II (NSGA-II) with multiple constraints han-dling is employed for multi-objective optimization of the topological structure of telescope skin, in which a bit-matrix is used as the representation of a chromosome, and genetic algorithm (GA) operators are introduced based on the matrix. Objectives including mass, in-plane performance, and out-of-plane load-bearing ability of the individuals are obtained by finite element analysis (FEA) using ANSYS, and the matrix-based optimization algorithm is realized in MATLAB by han-dling multiple constraints such as structural connectivity and in-plane strain requirements. Feasible configurations of the support structure are achieved. The results confirm that the matrix-based NSGA-II with multiple constraints handling provides an effective method for two-dimensional multi-objective topology optimization.
Optimal spectral norm rates for noisy low-rank matrix completion
Lounici, Karim
2011-01-01
In this paper we consider the trace regression model where $n$ entries or linear combinations of entries of an unknown $m_1\\times m_2$ matrix $A_0$ corrupted by noise are observed. We establish for the nuclear-norm penalized estimator of $A_0$ introduced in \\cite{KLT} a general sharp oracle inequality with the spectral norm for arbitrary values of $n,m_1,m_2$ under an incoherence condition on the sampling distribution $\\Pi$ of the observed entries. Then, we apply this method to the matrix completion problem. In this case, we prove that it satisfies an optimal oracle inequality for the spectral norm, thus improving upon the only existing result \\cite{KLT} concerning the spectral norm, which assumes that the sampling distribution is uniform. Note that our result is valid, in particular, in the high-dimensional setting $m_1m_2\\gg n$. Finally we show that the obtained rate is optimal up to logarithmic factors in a minimax sense.
Covariance and crossover matrix guided differential evolution for global numerical optimization.
Li, YongLi; Feng, JinFu; Hu, JunHua
2016-01-01
Differential evolution (DE) is an efficient and robust evolutionary algorithm and has wide application in various science and engineering fields. DE is sensitive to the selection of mutation and crossover strategies and their associated control parameters. However, the structure and implementation of DEs are becoming more complex because of the diverse mutation and crossover strategies that use distinct parameter settings during the different stages of the evolution. A novel strategy is used in this study to improve the crossover and mutation operations. The crossover matrix, instead of a crossover operator and its control parameter CR, is proposed to implement the function of the crossover operation. Meanwhile, Gaussian distribution centers the best individuals found in each generation based on the proposed covariance matrix, which is generated between the best individual and several better individuals. Improved mutation operator based on the crossover matrix is randomly selected to generate the trial population. This operator is used to generate high-quality solutions to improve the capability of exploitation and enhance the preference of exploration. In addition, the memory population is randomly chosen from previous generation and used to control the search direction in the novel mutation strategy. Accordingly, the diversity of the population is improved. Thus, CCDE, which is a novel efficient and simple DE variant, is presented in this paper. CCDE has been tested on 30 benchmarks and 5 real-world optimization problems from the IEEE Congress on Evolutionary Computation (CEC) 2014 and CEC 2011, respectively. Experimental and statistical results demonstrate the effectiveness of CCDE for global numerical and engineering optimization. CCDE can solve the test benchmark functions and engineering problems more successfully than the other DE variants and algorithms from CEC 2014.
Energy Technology Data Exchange (ETDEWEB)
Abbas, Tahir; Lowes, Tom [Cinar Ltd., London (United Kingdom)
2012-07-01
By means of MI-CFD modeling, improvements to AFR thermal substitution rates (TSR) can be easily validated. Case study II shows, how natural gas can be replaced by alternative fuels. The first part of the article in issue 5/2012 dealt with the basics and case study I. It was shown, how MI-CFD modelling can be used to understand the thermo-fluid dynamics of a calciner. In Part II a second case study and suggestions for the utilization of AFR are presented. (orig.)
Optimization of Thermoelectric Properties by Cu Substitution in LaCoO3 Ceramics
Choudhary, K. K.; Kaurav, N.; Ghosh, S. K.
2014-02-01
The thermoelectric properties of LaCo1-xCuxO3-δ ceramics are theoretically analyzed, it is observed that thermoelectric figure of merit ZT ( = S2σT/κ) is maximized by Cu substitution in LaCo1-xCux O3-δ at x = 0.15. The lattice thermal conductivity (κph) and phonon drag thermoelectric power (S ph drag) were estimated by the scattering of phonons with defects, grain boundaries, electrons and phonon umklapp scattering to evaluate the thermoelectric figure of merit ZT. The Mott expression is used to estimate the electron diffusive thermoelectric power (Se diff) using Fermi energy as electron free parameter, Se diff shows linear temperature dependence. The electron contribution to thermal conductivity (κe) is estimated using temperature-dependent electron relaxation time. We found that Cu substitution increases the phonon scattering with grain boundaries and defects which significantly decrease the thermal conductivity and subsequently increase the thermoelectric power. The present numerical analysis of thermoelectric properties will help in designing more efficient thermoelectric materials for thermoelectric applications.
Hierarchical approach to optimization of parallel matrix multiplication on large-scale platforms
Hasanov, Khalid
2014-03-04
© 2014, Springer Science+Business Media New York. Many state-of-the-art parallel algorithms, which are widely used in scientific applications executed on high-end computing systems, were designed in the twentieth century with relatively small-scale parallelism in mind. Indeed, while in 1990s a system with few hundred cores was considered a powerful supercomputer, modern top supercomputers have millions of cores. In this paper, we present a hierarchical approach to optimization of message-passing parallel algorithms for execution on large-scale distributed-memory systems. The idea is to reduce the communication cost by introducing hierarchy and hence more parallelism in the communication scheme. We apply this approach to SUMMA, the state-of-the-art parallel algorithm for matrix–matrix multiplication, and demonstrate both theoretically and experimentally that the modified Hierarchical SUMMA significantly improves the communication cost and the overall performance on large-scale platforms.
Hu, Weifeng; Chan, Garnet Kin-Lic
2015-07-14
We describe and extend the formalism of state-specific analytic density matrix renormalization group (DMRG) energy gradients, first used by Liu et al. [J. Chem. Theor. Comput. 2013, 9, 4462]. We introduce a DMRG wave function maximum overlap following technique to facilitate state-specific DMRG excited-state optimization. Using DMRG configuration interaction (DMRG-CI) gradients, we relax the low-lying singlet states of a series of trans-polyenes up to C20H22. Using the relaxed excited-state geometries, as well as correlation functions, we elucidate the exciton, soliton, and bimagnon ("single-fission") character of the excited states, and find evidence for a planar conical intersection.
Gunnels, John
2010-06-01
We provide a first demonstration of the idea that matrix-based algorithms for nonlinear combinatorial optimization problems can be efficiently implemented. Such algorithms were mainly conceived by theoretical computer scientists for proving efficiency. We are able to demonstrate the practicality of our approach by developing an implementation on a massively parallel architecture, and exploiting scalable and efficient parallel implementations of algorithms for ultra high-precision linear algebra. Additionally, we have delineated and implemented the necessary algorithmic and coding changes required in order to address problems several orders of magnitude larger, dealing with the limits of scalability from memory footprint, computational efficiency, reliability, and interconnect perspectives. © Springer and Mathematical Programming Society 2010.
Optimization of the Dutch Matrix Test by Random Selection of Sentences From a Preselected Subset
Directory of Open Access Journals (Sweden)
Rolph Houben
2015-04-01
Full Text Available Matrix tests are available for speech recognition testing in many languages. For an accurate measurement, a steep psychometric function of the speech materials is required. For existing tests, it would be beneficial if it were possible to further optimize the available materials by increasing the function’s steepness. The objective is to show if the steepness of the psychometric function of an existing matrix test can be increased by selecting a homogeneous subset of recordings with the steepest sentence-based psychometric functions. We took data from a previous multicenter evaluation of the Dutch matrix test (45 normal-hearing listeners. Based on half of the data set, first the sentences (140 out of 311 with a similar speech reception threshold and with the steepest psychometric function (≥9.7%/dB were selected. Subsequently, the steepness of the psychometric function for this selection was calculated from the remaining (unused second half of the data set. The calculation showed that the slope increased from 10.2%/dB to 13.7%/dB. The resulting subset did not allow the construction of enough balanced test lists. Therefore, the measurement procedure was changed to randomly select the sentences during testing. Random selection may interfere with a representative occurrence of phonemes. However, in our material, the median phonemic occurrence remained close to that of the original test. This finding indicates that phonemic occurrence is not a critical factor. The work highlights the possibility that existing speech tests might be improved by selecting sentences with a steep psychometric function.
Optimization of the Dutch matrix test by random selection of sentences from a preselected subset.
Houben, Rolph; Dreschler, Wouter A
2015-05-11
Matrix tests are available for speech recognition testing in many languages. For an accurate measurement, a steep psychometric function of the speech materials is required. For existing tests, it would be beneficial if it were possible to further optimize the available materials by increasing the function's steepness. The objective is to show if the steepness of the psychometric function of an existing matrix test can be increased by selecting a homogeneous subset of recordings with the steepest sentence-based psychometric functions. We took data from a previous multicenter evaluation of the Dutch matrix test (45 normal-hearing listeners). Based on half of the data set, first the sentences (140 out of 311) with a similar speech reception threshold and with the steepest psychometric function (≥9.7%/dB) were selected. Subsequently, the steepness of the psychometric function for this selection was calculated from the remaining (unused) second half of the data set. The calculation showed that the slope increased from 10.2%/dB to 13.7%/dB. The resulting subset did not allow the construction of enough balanced test lists. Therefore, the measurement procedure was changed to randomly select the sentences during testing. Random selection may interfere with a representative occurrence of phonemes. However, in our material, the median phonemic occurrence remained close to that of the original test. This finding indicates that phonemic occurrence is not a critical factor. The work highlights the possibility that existing speech tests might be improved by selecting sentences with a steep psychometric function.
Energy Technology Data Exchange (ETDEWEB)
Tisdale, Evgenia; Kennedy, Devin; Wilkins, Charles, E-mail: cwilkins@uark.edu
2014-01-15
Graphical abstract: -- Highlights: •We optimized sample preparation for MALDI TOF poly(styrene-copentafluorostyrene) co-polymers. •Influence of matrix choice was investigated. •Influence of matrix/analyte ratio was examined. •Influence of analyte/salt ratio (for Ag+ salt) was studied. -- Abstract: The influence of the sample preparation parameters (the choice of the matrix, matrix:analyte ratio, salt:analyte ratio) was investigated and optimal conditions were established for the MALDI time-of-flight mass spectrometry analysis of the poly(styrene-co-pentafluorostyrene) copolymers. These were synthesized by atom transfer radical polymerization. Use of 2,5-dihydroxybenzoic acid as matrix resulted in spectra with consistently high ion yields for all matrix:analyte:salt ratios tested. The optimized MALDI procedure was successfully applied to the characterization of three copolymers obtained by varying the conditions of polymerization reaction. It was possible to establish the nature of the end groups, calculate molecular weight distributions, and determine the individual length distributions for styrene and pentafluorostyrene monomers, contained in the resulting copolymers. Based on the data obtained, it was concluded that individual styrene chain length distributions are more sensitive to the change in the composition of the catalyst (the addition of small amount of CuBr{sub 2}) than is the pentafluorostyrene component distribution.
Energy Technology Data Exchange (ETDEWEB)
Abbas, Tahir; Lowes, Tom [Cinar Ltd., London (United Kingdom)
2012-07-01
The proposed upgrade was thoroughly assessed through MI-CFD simulations. In the light of previous experience at other plants, it was decided to improve the performance of the petcoke burner by introducing a higher momentum, which resulted in increasing the burning rate of petcoke at almost 11 % and also raised the calcination level by 6 %. An increase, that was achieved mainly through particle penetration into the riser duct flow and improved mixing with the region of high oxygen as can be seen from Figure 14 where petcoke particles are seen to be dispersing more into riser duct flow. The plant subsequently abandoned the extension of the riser duct by 3 m and implemented the higher momentum burner option, which was more cost effective than extending the volume of the calciner. In addition, after presentation of complete MI-CFD analysis, the incorporation of the tertiary air duct was also adjourned for a future plant upgrade and a more convenient and cost effective burner modification, installation of tailored high momentum burner, was accomplished by spending less than 50 000 Euro. After operating about one year, the plant reported the following benefits: 8 % increase in the calcination levels; carbon in the hot meal reduced from 0.3 to 0.1; less deposit build-up and ring formation; fuel substitution in the precalciner increased by 5 %; clinker production increased by 4 %. (orig.)
Directory of Open Access Journals (Sweden)
Mahendar Rupavath
2016-05-01
Full Text Available The aim of the present investigation was to develop floating matrix tablets of stavudine to achieve prolong gastric residence time, leading to an increase in drug bioavailability and patient compliance. Floating tablets were prepared by wet granulation technique, using hydroxypropyl methylcellulose (HPMC K15M as synthetic, pullulan gum as natural rate controlling polymers and optimum amounts of sodium-bicarbonate and citric acid as gas generating agents in suitable ratios to generate optimum buoyancy. Developed formulations were evaluated for weight variation, thickness, hardness, friability, drug content, in vitro drug release, floating lag time and floating buoyancy. All the formulations exhibited acceptable physical properties and the best formulation (F3 was selected based on in vitro characteristics. Further, the optimized formulation was evaluated for in vivo radiographic studies by incorporating BaSO4 as radio opaque substance. All the formulations were studied for in vitro drug release characteristics for 16 h. Optimized formulation showed controlled and prolonged drug release profiles while floating over the dissolution medium. Diffusion followed by erosion drug release mechanism was observed for the formulation, indicating that water diffusion and polymer erosion played an essential role in drug release. In vivo radiographic studies revealed that the tablets remained in the stomach for 8 ± 0.5 h in fasting human volunteers and indicated that gastric retention time was increased by the floating principle, which was considered and desirable for absorption window drugs.
Optimization of Sparse Matrix-Vector Multiplication on Emerging Multicore Platforms
Energy Technology Data Exchange (ETDEWEB)
Williams, Samuel; Oliker, Leonid; Vuduc, Richard; Shalf, John; Yelick, Katherine; Demmel, James
2008-10-16
We are witnessing a dramatic change in computer architecture due to the multicore paradigm shift, as every electronic device from cell phones to supercomputers confronts parallelism of unprecedented scale. To fully unleash the potential of these systems, the HPC community must develop multicore specific-optimization methodologies for important scientific computations. In this work, we examine sparse matrix-vector multiply (SpMV) - one of the most heavily used kernels in scientific computing - across a broad spectrum of multicore designs. Our experimental platform includes the homogeneous AMD quad-core, AMD dual-core, and Intel quad-core designs, the heterogeneous STI Cell, as well as one of the first scientific studies of the highly multithreaded Sun Victoria Falls (a Niagara2 SMP). We present several optimization strategies especially effective for the multicore environment, and demonstrate significant performance improvements compared to existing state-of-the-art serial and parallel SpMV implementations. Additionally, we present key insights into the architectural trade-offs of leading multicore design strategies, in the context of demanding memory-bound numerical algorithms.
Optimization of sparse matrix-vector multiplication on emerging multicore platforms
Energy Technology Data Exchange (ETDEWEB)
Williams, S; Oliker, L; Vuduc, R; Shalf, J; Yelick, K; Demmel, J
2007-04-16
We are witnessing a dramatic change in computer architecture due to the multicore paradigm shift, as every electronic device from cell phones to supercomputers confronts parallelism of unprecedented scale. To fully unleash the potential of these systems, the HPC community must develop multicore specific optimization methodologies for important scientific computations. In this work, we examine sparse matrix-vector multiply (SpMV)--one of the most heavily used kernels in scientific computing--across a broad spectrum of multicore designs. Our experimental platform includes the homogeneous AMD dual-core and Intel quad-core designs, as well as the highly multithreaded Sun Niagara and heterogeneous STI Cell. We present several optimization strategies especially effective for the multicore environment, and demonstrate significant performance improvements compared to existing state-of-the-art serial and parallel SpMV implementations. Additionally, we present key insights into the architectural tradeoffs of leading multicore design strategies, in the context of demanding memory-bound numerical algorithms.
McMinn, Dustin L; Rew, Yosup; Sudom, Athena; Caille, Seb; Degraffenreid, Michael; He, Xiao; Hungate, Randall; Jiang, Ben; Jaen, Juan; Julian, Lisa D; Kaizerman, Jacob; Novak, Perry; Sun, Daqing; Tu, Hua; Ursu, Stefania; Walker, Nigel P C; Yan, Xuelei; Ye, Qiuping; Wang, Zhulun; Powers, Jay P
2009-03-01
Novel 4,4-disubstituted cyclohexylbenzamide inhibitors of 11beta-HSD1 were optimized to account for liabilities relating to in vitro pharmacokinetics, cytotoxicity and protein-related shifts in potency. A representative compound showing favorable in vivo pharmacokinetics was found to be an efficacious inhibitor of 11beta-HSD1 in a rat pharmacodynamic model (ED(50)=10mg/kg).
Pontiggia, Luca; Klar, Agnieszka; Böttcher-Haberzeth, Sophie; Biedermann, Thomas; Meuli, Martin; Reichmann, Ernst
2013-03-01
Autologous dermo-epidermal skin substitutes (DESS) generated in vitro represent a promising therapeutic means to treat full-thickness skin defects in clinical practice. A serious drawback with regard to acute patients is the relatively long production time of 3-4 weeks. With this experimental study we aimed to decrease the production time of DESS without compromising their quality. Two in vitro steps of DESS construction were varied: the pre-cultivation time of fibroblasts in hydrogels (1, 3, and 6 days), and the culture time of keratinocytes (3, 6, and 12 days) before transplantation of DESS on nude rats. Additionally, the impact of the air-liquid interface culture during 3 days before transplantation was investigated. 3 weeks after transplantation, the macroscopic appearance was evaluated and histological sections were produced to analyze structure and thickness of epidermis and dermis, the stratification of the epidermis, and the presence of a basal lamina. Optimal DESS formation was obtained with a fibroblast pre-cultivation time of 6 days. The minimal culture time of keratinocytes on hydrogels was also 6 days. The air-liquid interface culture did not improve graft quality. By optimizing our in vitro culture conditions, it was possible to very substantially reduce the production time for DESS from 21 to 12 days. However, pre-cultivation of fibroblasts in the dermal equivalent and proliferation of keratinocytes before transplantation remain crucial for an equilibrated maturation of the epidermis and cannot be completely skipped.
Data Hiding by LSB Substitution Using Genetic Optimal Key-Permutation
Directory of Open Access Journals (Sweden)
Marghny Mohamed
2011-01-01
Full Text Available The least significant bit (LSB embedding method is one of the most commonly used techniques; it targets the LSB'sof the host image to hide the data. This paper deals with three main steganography challenges (i.e. capacity, imperceptibility,and security. This is achieved by hybrid data hiding scheme incorporates LSB technique with a key-permutation method. Thepaper also proposes an optimal key permutation method using genetic algorithms for best key selection. Both normal andoptimized methods are tested with standard images, varying both data size as well as key space. Final experimental resultsshow decrement in computation time when increasing number of keys, at the same time system security improves.
Directory of Open Access Journals (Sweden)
Wanxing Sheng
2016-05-01
Full Text Available In this paper, a reactive power optimization method based on historical data is investigated to solve the dynamic reactive power optimization problem in distribution network. In order to reflect the variation of loads, network loads are represented in a form of random matrix. Load similarity (LS is defined to measure the degree of similarity between the loads in different days and the calculation method of the load similarity of load random matrix (LRM is presented. By calculating the load similarity between the forecasting random matrix and the random matrix of historical load, the historical reactive power optimization dispatching scheme that most matches the forecasting load can be found for reactive power control usage. The differences of daily load curves between working days and weekends in different seasons are considered in the proposed method. The proposed method is tested on a standard 14 nodes distribution network with three different types of load. The computational result demonstrates that the proposed method for reactive power optimization is fast, feasible and effective in distribution network.
Optimizing Polymer Infusion Process for Thin Ply Textile Composites with Novel Matrix System
Directory of Open Access Journals (Sweden)
Somen K. Bhudolia
2017-03-01
Full Text Available For mass production of structural composites, use of different textile patterns, custom preforming, room temperature cure high performance polymers and simplistic manufacturing approaches are desired. Woven fabrics are widely used for infusion processes owing to their high permeability but their localised mechanical performance is affected due to inherent associated crimps. The current investigation deals with manufacturing low-weight textile carbon non-crimp fabrics (NCFs composites with a room temperature cure epoxy and a novel liquid Methyl methacrylate (MMA thermoplastic matrix, Elium®. Vacuum assisted resin infusion (VARI process is chosen as a cost effective manufacturing technique. Process parameters optimisation is required for thin NCFs due to intrinsic resistance it offers to the polymer flow. Cycles of repetitive manufacturing studies were carried out to optimise the NCF-thermoset (TS and NCF with novel reactive thermoplastic (TP resin. It was noticed that the controlled and optimised usage of flow mesh, vacuum level and flow speed during the resin infusion plays a significant part in deciding the final quality of the fabricated composites. The material selections, the challenges met during the manufacturing and the methods to overcome these are deliberated in this paper. An optimal three stage vacuum technique developed to manufacture the TP and TS composites with high fibre volume and lower void content is established and presented.
Polisetty, S.; Scheffler, J.; Sahoo, S.; Wang, Yi; Mukherjee, T.; He, Xi; Binek, Ch.
2008-05-01
We present a comparative study on an experimental and theoretical optimization of magneto-optical Kerr setups based on photoelastic modulation and phase sensitive detector methodology. The first and second harmonics, Iω ,2ω, of the reflected light intensity are measured for a CoO /Co magnetic reference film. The magnetic field dependence of the optical off-diagonal Fresnel reflection coefficients rps and rsp follows the sample magnetization. Different Kerr setups provide various dependencies of Iω ,2ω on the reflection coefficients and, hence, on the Kerr ellipticity ɛK and rotation θK. Jones matrix formalism has been used to analyze the impact of a systematic variation of relative analyzer and polarizer orientations with respect to each other and with respect to the retardation axis of the modulator involved in longitudinal Kerr setups for incoming s-polarized light. We find one particular setup which maximizes Iω as well as I2ω and maximizes the signal-to-noise ratio. Inefficient setups are characterized by Iω ,2ω intensities involving large nonmagnetic contributions of rp and rs.
Polisetty, S; Scheffler, J; Sahoo, S; Wang, Yi; Mukherjee, T; He, Xi; Binek, Ch
2008-05-01
We present a comparative study on an experimental and theoretical optimization of magneto-optical Kerr setups based on photoelastic modulation and phase sensitive detector methodology. The first and second harmonics, I omega,2 omega, of the reflected light intensity are measured for a CoO/Co magnetic reference film. The magnetic field dependence of the optical off-diagonal Fresnel reflection coefficients rps and rsp follows the sample magnetization. Different Kerr setups provide various dependencies of I omega,2 omega on the reflection coefficients and, hence, on the Kerr ellipticity epsilon K and rotation theta K. Jones matrix formalism has been used to analyze the impact of a systematic variation of relative analyzer and polarizer orientations with respect to each other and with respect to the retardation axis of the modulator involved in longitudinal Kerr setups for incoming s-polarized light. We find one particular setup which maximizes I(omega) as well as I2 omega and maximizes the signal-to-noise ratio. Inefficient setups are characterized by I omega,2 omega intensities involving large nonmagnetic contributions of rp and rs.
Optimization of MOKE Setups: Analyzing Experimental Assemblies Using Jones Matrix Formalism
Polisetty, Srinivas; Scheffler, Jeremy; Sahoo, Sarbeswar; Binek, Christian
2008-03-01
We report on the optimization of Magneto Optical Kerr setups. Photoelastic modulation and phase sensitive detector methodology have been used to measure the first and second harmonics of the reflected light intensity related to the magnetization-dependent off-diagonal reflection coefficients rps/sp of the sample's dielectric tensor. The latter elements determine the Kerr ellipticity ɛK and rotation θK. Jones matrix formalism has been used to analyze a large variety of arrangements of the optical elements involved in setups for longitudinal Kerr measurements with incoming s-polarized light. Relative analyzer and polarizer orientations have been varied with respect to each other and with respect to the retardation axis of the modulator. Different configurations have been analyzed and experimentally studied by measuring magnetic Kerr-hysteresis loops on a Co/CoO bilayer sample. We find that one configuration stands out by doubling the first as well as second harmonic intensities and, hence, the signal to noise ratio. Inefficient setups show first and second harmonic signals involving non-magnetic background contributions of rp and rs.
A density-dependent matrix model and its applications in optimizing harvest schemes
Institute of Scientific and Technical Information of China (English)
Guofan Shao; WANG Fei; DAI Limin; BAI Jianwei; LI Yingshan
2006-01-01
Based on temporal data collected from 36 re-measured plots, transition probabilities of trees from a diameter class to a higher class were analyzed for the broadleaved-Korean pine forest in the Changbai Mountains. It was found that the transition probabilities were related not only to diameter size but also to the total basal area of trees with the diameter class. This paper demonstrates the development of a density-dependent matrix model, DM2, and a series of simulations with it for forest stands with different conditions under different harvest schemes. After validations with independent field data, this model proved a suitable tool for optimization analysis of harvest schemes on computers. The optimum harvest scheme(s) can be determined by referring to stand growth, total timbers harvested, and size diversity changes over time. Three user-friendly interfaces were built with a forest management decision support system FORESTAR(R) for easy operations of DM2 by forest managers. This paper also summarizes the advantages and disadvantages of DM2.
Optimizing Polymer Infusion Process for Thin Ply Textile Composites with Novel Matrix System
Bhudolia, Somen K.; Perrotey, Pavel; Joshi, Sunil C.
2017-01-01
For mass production of structural composites, use of different textile patterns, custom preforming, room temperature cure high performance polymers and simplistic manufacturing approaches are desired. Woven fabrics are widely used for infusion processes owing to their high permeability but their localised mechanical performance is affected due to inherent associated crimps. The current investigation deals with manufacturing low-weight textile carbon non-crimp fabrics (NCFs) composites with a room temperature cure epoxy and a novel liquid Methyl methacrylate (MMA) thermoplastic matrix, Elium®. Vacuum assisted resin infusion (VARI) process is chosen as a cost effective manufacturing technique. Process parameters optimisation is required for thin NCFs due to intrinsic resistance it offers to the polymer flow. Cycles of repetitive manufacturing studies were carried out to optimise the NCF-thermoset (TS) and NCF with novel reactive thermoplastic (TP) resin. It was noticed that the controlled and optimised usage of flow mesh, vacuum level and flow speed during the resin infusion plays a significant part in deciding the final quality of the fabricated composites. The material selections, the challenges met during the manufacturing and the methods to overcome these are deliberated in this paper. An optimal three stage vacuum technique developed to manufacture the TP and TS composites with high fibre volume and lower void content is established and presented. PMID:28772654
A Bayes optimal matrix-variate LDA for extraction of spatio-spectral features from EEG signals.
Mahanta, Mohammad Shahin; Aghaei, Amirhossein S; Plataniotis, Konstantinos N
2012-01-01
Classification of mental states from electroencephalogram (EEG) signals is used for many applications in areas such as brain-computer interfacing (BCI). When represented in the frequency domain, the multichannel EEG signal can be considered as a two-directional spatio-spectral data of high dimensionality. Extraction of salient features using feature extractors such as the commonly used linear discriminant analysis (LDA) is an essential step for the classification of these signals. However, multichannel EEG is naturally in matrix-variate format, while LDA and other traditional feature extractors are designed for vector-variate input. Consequently, these methods require a prior vectorization of the EEG signals, which ignores the inherent matrix-variate structure in the data and leads to high computational complexity. A matrix-variate formulation of LDA have previously been proposed. However, this heuristic formulation does not provide the Bayes optimality benefits of LDA. The current paper proposes a Bayes optimal matrix-variate formulation of LDA based on a matrix-variate model for the spatio-spectral EEG patterns. The proposed formulation also provides a strategy to select the most significant features among the different rows and columns.
Zare Hosseinzadeh, A.; Ghodrati Amiri, G.; Seyed Razzaghi, S. A.; Koo, K. Y.; Sung, S. H.
2016-10-01
This paper is aimed at presenting a novel and effective method to detect and estimate structural damage by introducing an efficient objective function which is based on Modal Assurance Criterion (MAC) and modal flexibility matrix. The main strategy in the proposed objective function relies on searching a geometrical correlation between two vectors. Democratic Particle Swarm Optimization (DPSO) algorithm, a modified version of original PSO approach, is used to minimize the objective function resulting in the assessment of damage in different structure types. Finally, the presented method is generalized for a condition in which a limited number of sensors are installed on the structure using Neumann Series Expansion-based Model Reduction (NSEMR) approach. To evaluate the efficiency of the proposed method, different damage patterns in three numerical examples of engineering structures are simulated and the proposed method is employed for damage identification. Moreover, the stability of the method is investigated by considering the effects of a number of important challenges such as effects of different locations for sensor installation, prevalent modeling errors and presence of random noises in the input data. It is followed by different comparative studies to evaluate not only the robustness of the proposed method, but also the necessity of using introduced techniques for problem solution. Finally, the applicability of the presented method in real conditions is also verified by an experimental study of a five-story shear frame on a shaking table utilizing only three sensors. All of the obtained results demonstrate that the proposed method precisely identifies damages by using only the first several modes' data, even when incomplete noisy modal data are considered as input data.
Ogungbenro, Kayode; Aarons, Leon
2011-08-01
In the recent years, interest in the application of experimental design theory to population pharmacokinetic (PK) and pharmacodynamic (PD) experiments has increased. The aim is to improve the efficiency and the precision with which parameters are estimated during data analysis and sometimes to increase the power and reduce the sample size required for hypothesis testing. The population Fisher information matrix (PFIM) has been described for uniresponse and multiresponse population PK experiments for design evaluation and optimisation. Despite these developments and availability of tools for optimal design of population PK and PD experiments much of the effort has been focused on repeated continuous variable measurements with less work being done on repeated discrete type measurements. Discrete data arise mainly in PDs e.g. ordinal, nominal, dichotomous or count measurements. This paper implements expressions for the PFIM for repeated ordinal, dichotomous and count measurements based on analysis by a mixed-effects modelling technique. Three simulation studies were used to investigate the performance of the expressions. Example 1 is based on repeated dichotomous measurements, Example 2 is based on repeated count measurements and Example 3 is based on repeated ordinal measurements. Data simulated in MATLAB were analysed using NONMEM (Laplace method) and the glmmML package in R (Laplace and adaptive Gauss-Hermite quadrature methods). The results obtained for Examples 1 and 2 showed good agreement between the relative standard errors obtained using the PFIM and simulations. The results obtained for Example 3 showed the importance of sampling at the most informative time points. Implementation of these expressions will provide the opportunity for efficient design of population PD experiments that involve discrete type data through design evaluation and optimisation.
Jiang, Ling; Wang, Jufang; Liang, Shizhong; Cai, Jin; Xu, Zhinan
2011-09-01
The great performance of a fibrous bed bioreactor (FBB) is mainly dependent on the cell adhesion and immobilization into the fibrous matrix. Therefore, understanding the mechanism and factors controling cell adhesion in the fibrous matrix is necessary to optimize the FBB setup and further improve the fermentability. The adhesion behavior of a strain of Clostridium tyrobutyricum isolated from an FBB was studied, which was proven to be affected by the different environmental conditions, such as growth phase of cells, pH, ionic strength, ionic species, and composition of media. Our results also suggested that electrostatic interactions played an important role on bacteria adhesion into the fibrous matrix. This study demonstrated that the compositions of fermentation broth would have a significant effect on cell adhesion. Consequently, a two-stage glucose supply control strategy was developed to improve the performance of FBB with higher viable cell density in the operation of the FBB setup.
Choi, Du Hyung; Lim, Jun Yeul; Shin, Sangmun; Choi, Won Jun; Jeong, Seong Hoon; Lee, Sangkil
2014-10-01
To investigate the effects of hydrophilic polymers on the matrix system, an experimental design method was developed to integrate response surface methodology and the time series modeling. Moreover, the relationships among polymers on the matrix system were studied with the evaluation of physical properties including water uptake, mass loss, diffusion, and gelling index. A mixture simplex lattice design was proposed while considering eight input control factors: Polyethylene glycol 6000 (x1 ), polyethylene oxide (PEO) N-10 (x2 ), PEO 301 (x3 ), PEO coagulant (x4 ), PEO 303 (x5 ), hydroxypropyl methylcellulose (HPMC) 100SR (x6 ), HPMC 4000SR (x7 ), and HPMC 10(5) SR (x8 ). With the modeling, optimal formulations were obtained depending on the four types of targets. The optimal formulations showed the four significant factors (x1 , x2 , x3 , and x8 ) and other four input factors (x4 , x5 , x6 , and x7 ) were not significant based on drug release profiles. Moreover, the optimization results were analyzed with estimated values, targets values, absolute biases, and relative biases based on observed times for the drug release rates with four different targets. The result showed that optimal solutions and target values had consistent patterns with small biases. On the basis of the physical properties of the optimal solutions, the type and ratio of the hydrophilic polymer and the relationships between polymers significantly influenced the physical properties of the system and drug release. This experimental design method is very useful in formulating a matrix system with optimal drug release. Moreover, it can distinctly confirm the relationships between excipients and the effects on the system with extensive and intensive evaluations.
Heuristic computation of the rovibrational G matrix in optimized molecule-fixed axes. Gmat 2.1
Castro, M. E.; Niño, A.; Muñoz-Caro, C.
2010-08-01
Gmat 2.1 is a program able to compute the rovibrational G matrix in different molecule-fixed axes extending the capabilities of Gmat 1.0. The present version is able to select optimal molecule-fixed axes minimizing the pure rotational kinetic elements, the rovibrational kinetic elements or both simultaneously. To such an end, it uses a hybrid minimization approach. Thus, it combines a global search heuristic based in simulated annealing with a gradient-free local minimization. As the previous version, the program handles the structural results of potential energy hypersurface mappings computed in computer clusters or computational Grid environments. However, since now more general molecule-fixed axes can be defined, a procedure is implemented to ensure the same minimum of the cost function is used in all the molecular structures. In addition, an algorithm for the unambiguous definition of the molecule-fixed axes orientation is used. Program summaryProgram title: Gmat 2.1 Catalogue identifier: AECZ_v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AECZ_v2_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 52 555 No. of bytes in distributed program, including test data, etc.: 932 366 Distribution format: tar.gz Programming language: Standard ANSI C++ Computer: All Operating system: Linux, Windows Classification: 16.2 Catalogue identifier of previous version: AECZ_v1_0 Journal reference of previous version: Comput. Phys. Comm. 180 (2009) 1183 Does the new version supersede the previous version?: Yes Nature of problem: When building molecular rovibrational Hamiltonians, the kinetic terms depend on the molecule-fixed axes orientation. Thus, an appropriate orientation can significantly simplify the treatment of pure rotation and rovibrational coupling. The kinetic terms
Chin-Pampillo, Juan Salvador; Ruiz-Hidalgo, Karla; Masís-Mora, Mario; Carazo-Rojas, Elizabeth; Rodríguez-Rodríguez, Carlos E
2015-12-01
Pesticide biopurification systems contain a biologically active matrix (biomixture) responsible for the accelerated elimination of pesticides in wastewaters derived from pest control in crop fields. Biomixtures have been typically prepared using the volumetric composition 50:25:25 (lignocellulosic substrate/humic component/soil); nonetheless, formal composition optimization has not been performed so far. Carbofuran is an insecticide/nematicide of high toxicity widely employed in developing countries. Therefore, the composition of a highly efficient biomixture (composed of coconut fiber, compost, and soil, FCS) for the removal of carbofuran was optimized by means of a central composite design and response surface methodology. The volumetric content of soil and the ratio coconut fiber/compost were used as the design variables. The performance of the biomixture was assayed by considering the elimination of carbofuran, the mineralization of (14)C-carbofuran, and the residual toxicity of the matrix, as response variables. Based on the models, the optimal volumetric composition of the FCS biomixture consists of 45:13:42 (coconut fiber/compost/soil), which resulted in minimal residual toxicity and ∼99% carbofuran elimination after 3 days. This optimized biomixture considerably differs from the standard 50:25:25 composition, which remarks the importance of assessing the performance of newly developed biomixtures during the design of biopurification systems.
Energy Technology Data Exchange (ETDEWEB)
Ribes, Aurelien; Planton, Serge [CNRM-GAME, Meteo France-CNRS, Toulouse (France); Azais, Jean-Marc [Universite de Toulouse, UPS, IMT, LSP, Toulouse (France)
2009-10-15
The ''optimal fingerprint'' method, usually used for detection and attribution studies, requires to know, or, in practice, to estimate the covariance matrix of the internal climate variability. In this work, a new adaptation of the ''optimal fingerprints'' method is presented. The main goal is to allow the use of a covariance matrix estimate based on an observation dataset in which the number of years used for covariance estimation is close to the number of observed time series. Our adaptation is based on the use of a regularized estimate of the covariance matrix, that is well-conditioned, and asymptotically more precise, in the sense of the mean square error. This method is shown to be more powerful than the basic ''guess pattern fingerprint'', and than the classical use of a pseudo-inverted truncation of the empirical covariance matrix. The construction of the detection test is achieved by using a bootstrap technique particularly well-suited to estimate the internal climate variability in real world observations. In order to validate the efficiency of the detection algorithm with climate data, the methodology presented here is first applied with pseudo-observations derived from transient regional climate change scenarios covering the 1960-2099 period. It is then used to perform a formal detection study of climate change over France, analyzing homogenized observed temperature series from 1900 to 2006. In this case, the estimation of the covariance matrix is only based on a part of the observation dataset. This new approach allows the confirmation and extension of previous results regarding the detection of an anthropogenic climate change signal over the country. (orig.)
Poria, Suswagata; Sahoo, Prasanta; Sutradhar, Goutam
2016-09-01
The present study outlines the use of Taguchi parameter design to minimize the wear performance of Al-TiB2 metal matrix composites by optimizing tribological process parameters. Different weight percentages of micro-TiB2 powders with average sizes of 5-40 micron are incorporated into molten LM4 aluminium matrix by stir casting method. The wear performance of Al-TiB2 composites is evaluated in a block-on-roller type Multitribo tester at room temperature. Three parameters viz. weight percentage of TiB2, load and speed are considered with three levels each at the time of experiment. A L27 orthogonal array is used to carry out experiments accommodating all the factors and their levels including their interaction effects. Optimal combination of parameters for wear performance is obtained by Taguchi analysis. Analysis of variance (ANOVA) is used to find out percentage contribution of each parameter and their interaction also on wear performance. Weight percentage of TiB2 is forced to be the most effective parameter in controlling wear behaviour of Al-TiB2 metal matrix composite.
Oostendorp, C.; Meyer, S.; Sobrio, M.; Arendonk, J. van; Reichmann, E.; Daamen, W.F.; Kuppevelt, T.H. van
2017-01-01
Treatment of full-thickness skin defects with split-thickness skin grafts is generally associated with contraction and scar formation and cellular skin substitutes have been developed to improve skin regeneration. The evaluation of cultured skin substitutes is generally based on qualitative
Optimal Sparse Matrix Dense Vector Multiplication in the I/O-Model
DEFF Research Database (Denmark)
Bender, Michael A.; Brodal, Gerth Stølting; Fagerberg, Rolf
2010-01-01
We study the problem of sparse-matrix dense-vector multiplication (SpMV) in external memory. The task of SpMV is to compute y:=Ax, where A is a sparse Nx N matrix and x is a vector. We express sparsity by a parameter k, and for each choice of k consider the class of matrices where the number...... of nonzero entries is kN, i.e., where the average number of nonzero entries per column is k. We investigate what is the external worst-case complexity, i.e., the best possible upper bound on the number of I/Os, as a function of k and N. We determine this complexity up to a constant factor for all meaningful......(min{kN/Bmax{1,logM/B (N/max{k,M})},kN}) for k≤ N1-ε and any constant 0 matrix, the I...
Tholey, Andreas; Wittmann, Christoph; Kang, Min-Jung; Bungert, Ditte; Hollemeyer, Klaus; Heinzle, Elmar
2002-09-01
Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) is a powerful tool for the measurement of low molecular mass compounds of biological interest. The limitations for this method are the volatility of many analytes, possible interference with matrix signals or bad ionization or desorption behavior of the compounds. We investigated the application of well-known and straightforward one-pot derivatization procedures to circumvent these problems. The derivatizations tested allow the measurement and the labeling of alcohols, aldehydes and ketones, carboxylic acids, alpha-ketocarboxylic acids and amines.
Optimization of dielectric matrix for ZnO nanowire based nanogenerators
Kannan, Santhosh; Parmar, Mitesh; Tao, Ran; Ardila, Gustavo; Mouis, Mireille
2016-11-01
This paper reports the role of selection of suitable dielectric layer in nanogenerator (NG) structure and its influence on the output performance. The basic NG structure is a composite material integrating hydrothermally grown vertical piezoelectric zinc oxide (ZnO) nanowires (NWs) into a dielectric matrix. To accomplish this study, three materials - poly methyl methacrylate (PMMA), silicon nitride (Si3N4) and aluminium oxide (Al2O3) are selected, processed and used as matrix dielectric in NGs. Scanning electron microscopy (SEM) analysis shows the well-aligned NWs with a diameter of 200±50 nm and length of 3.5±0.3 μm. This was followed by dielectric material deposition as a matrix material. After fabricating NG devices, the output generated voltage under manual and automatic bending were recorded, observed and analyzed for the selection of the best dielectric material to obtain an optimum output. The maximum peak-to-peak open-circuit voltage output for PMMA, Si3N4 and Al2O3 under manual bending was recorded as approximately 880 mV, 1.2 V and 2.1 V respectively. These preliminary results confirm the predicted effect of using more rigid dielectrics as matrix material for the NGs. The generated voltage is increased by about 70% using Si3N4 or Al2O3, instead of a less rigid material as PMMA.
Optimal matrix rigidity for stress-fibre polarization in stem cells
Zemel, A.; Rehfeldt, F.; Brown, A. E. X.; Discher, D. E.; Safran, S. A.
2010-06-01
The shape and differentiated state of many cell types are highly sensitive to the rigidity of the microenvironment. The physical mechanisms involved, however, are unknown. Here, we present a theoretical model and experiments demonstrating that the alignment of stress fibres within stem cells is a non-monotonic function of matrix rigidity. We treat the cell as an active elastic inclusion in a surrounding matrix, allowing the actomyosin forces to polarize in response to elastic stresses developed in the cell. The theory correctly predicts the monotonic increase of the cellular forces with the matrix rigidity and the alignment of stress fibres parallel to the long axis of cells. We show that the anisotropy of this alignment depends non-monotonically on matrix rigidity and demonstrate it experimentally by quantifying the orientational distribution of stress fibres in stem cells. These findings offer physical insight into the sensitivity of stem-cell differentiation to tissue elasticity and, more generally, introduce a cell-type-specific parameter for actomyosin polarizability.
Directory of Open Access Journals (Sweden)
Francesco Giovanni Ceglie
Full Text Available Peat replacement is an increasing demand in containerized and transplant production, due to the environmental constraints associated to peat use. However, despite the wide information concerning the use of alternative materials as substrates, it is very complex to establish the best materials and mixtures. This work evaluates the use of mixture design and surface response methodology in a peat substitution experiment using two alternative materials (green compost and palm fibre trunk waste for transplant production of tomato (Lycopersicon esculentum Mill.; melon, (Cucumis melo L.; and lettuce (Lactuca sativa L. in organic farming conditions. In general, the substrates showed suitable properties for their use in seedling production, showing the best plant response the mixture of 20% green compost, 39% palm fibre and 31% peat. The mixture design and applied response surface methodology has shown to be an useful approach to optimize substrate formulations in peat substitution experiments to standardize plant responses.
Aas, Lars Martin S; Ellingsen, Pål G; Letnes, Paul Anton; Kildemo, Morten
2013-01-01
The design of broad-band polarimeters with high performance is challenging due to the wavelength dependence of optical components. An efficient Genetic Algorithm (GA) computer code was recently developed in order to design and re-optimize complete broadband Stokes polarimeters and Mueller matrix ellipsometers (MME). Our results are improvements of previous patented designs based on two and three ferroelectric liquid crystals (FLC), and are suited for broad-band hyperspectral imaging, or multichannel spectroscopy applications. We have realized and implemented one design using two FLCs and compare the spectral range and precision with previous designs.
Sun, Xuelian; Liu, Zixian
2016-02-01
In this paper, a new estimator of correlation matrix is proposed, which is composed of the detrended cross-correlation coefficients (DCCA coefficients), to improve portfolio optimization. In contrast to Pearson's correlation coefficients (PCC), DCCA coefficients acquired by the detrended cross-correlation analysis (DCCA) method can describe the nonlinear correlation between assets, and can be decomposed in different time scales. These properties of DCCA make it possible to improve the investment effect and more valuable to investigate the scale behaviors of portfolios. The minimum variance portfolio (MVP) model and the Mean-Variance (MV) model are used to evaluate the effectiveness of this improvement. Stability analysis shows the effect of two kinds of correlation matrices on the estimation error of portfolio weights. The observed scale behaviors are significant to risk management and could be used to optimize the portfolio selection.
Directory of Open Access Journals (Sweden)
Biswajit BHOWMIK
2011-01-01
Full Text Available Dynamic Programming is one of the sledgehammers of the algorithms craft in optimizations. The versatility of the dynamic programming method is really appreciated by exposure to a wide variety of applications. In this paper a modified algorithm is introduced to provide suitable procedure that ensures how to multiply a chain of matrices. The model Optimal Parenthesization Scheme using 2-Tree Generation (OPS2TG acts as one relevancies of the proposed algorithm. A new approach for how to break the matrix chain and how to insert parenthesis in it is also designed in this model. The comparison study between the proposed model and the classical approach shows acceptance of the model suggested here.
In-package P/G planes analysis and optimization based on transmission matrix method
Institute of Scientific and Technical Information of China (English)
Yin-jun WANG; Cheng ZHUO; Jun-yong DENG; Jin-fang ZHOU; Kang-sheng CHEN
2008-01-01
Power integrity (PI) has become a limiting factor for the chip's overall performance, and how to place in-package decoupling capacitors to improve a chip's PI performance has become a hot issue. In this paper, we propose an improved transmission matrix method (TMM) for fast decoupling capacitance allocation. An irregular grid partition mechanism is proposed, which helps speed up the impedance computation and complies better with the irregular power/ground (P/G) plane or planes with many vias and decoupling capacitors. Furthermore, we also ameliorate the computation procedure of the impedance matrix whenever decoupling capacitors are inserted or removed at specific ports. With the fast computation of impedance change, in-package decoupling capacitor allocation is done with an efficient change based method in the frequency domain. Experimental results show that our approach can gain about 5× speedup compared with a general TMM, and is efficient in restraining the noise on the P/G plane.
Energy Technology Data Exchange (ETDEWEB)
Hammami, Samiha [Laboratoire de Chimie Analytique et Electrochimie, Departement de Chimie, Faculte des Sciences de Tunis, Campus Universitaire, 2092 Tunis El Manar (Tunisia)], E-mail: samiha.hammami@laposte.net; Ouejhani, Ali [Laboratoire de Chimie Analytique et Electrochimie, Departement de Chimie, Faculte des Sciences de Tunis, Campus Universitaire, 2092 Tunis El Manar (Tunisia); Bellakhal, Nizar [Laboratoire de Chimie Analytique et Electrochimie, Departement de Chimie, Faculte des Sciences de Tunis, Campus Universitaire, 2092 Tunis El Manar (Tunisia); Departement de Chimie et de Biologie Appliquees, Institut National des Sciences Appliquees et de Technologie (INSAT), B.P. No676, 1080 Tunis Cedex (Tunisia); Dachraoui, Mohamed [Laboratoire de Chimie Analytique et Electrochimie, Departement de Chimie, Faculte des Sciences de Tunis, Campus Universitaire, 2092 Tunis El Manar (Tunisia)
2009-04-15
The oxidation of organic and inorganic pollutants present in tannery effluents has been realised by electrochemical way. The influence of the electrochemical reactor parameters was carried out by the use of Doehlert matrix. The obtained results have shown that the current intensity and the electrolysis time were the main influent parameters on the removal ratio of chemical oxygen demand (COD), total organic carbon (TOC), electrochemical oxidation of trivalent chromium and sulphite ions.
Mahendar Rupavath; Kranthi Kumar G; Palem, Chinna R.; K.S.K.RAO PATNAIK
2016-01-01
The aim of the present investigation was to develop floating matrix tablets of stavudine to achieve prolong gastric residence time, leading to an increase in drug bioavailability and patient compliance. Floating tablets were prepared by wet granulation technique, using hydroxypropyl methylcellulose (HPMC K15M) as synthetic, pullulan gum as natural rate controlling polymers and optimum amounts of sodium-bicarbonate and citric acid as gas generating agents in suitable ratios to generate optimum...
2008-05-01
dictionaries, state-of-the-art results in image denoising , inpainting, and demosaicing, have been obtained in the past [12]. This learning framework is also...14) At this point it is very tempting to obtain the SVD decomposition of and eliminate the largest component of the error matrix (see...to atom and ,T the rows of , where the zeros have been removed. Let T be the singular value decomposition ( SVD ) of R. Then, (16
All-at-once Optimization for Coupled Matrix and Tensor Factorizations
Acar, Evrim; Dunlavy, Daniel M
2011-01-01
Joint analysis of data from multiple sources has the potential to improve our understanding of the underlying structures in complex data sets. For instance, in restaurant recommendation systems, recommendations can be based on rating histories of customers. In addition to rating histories, customers' social networks (e.g., Facebook friendships) and restaurant categories information (e.g., Thai or Italian) can also be used to make better recommendations. The task of fusing data, however, is challenging since data sets can be incomplete and heterogeneous, i.e., data consist of both matrices, e.g., the person by person social network matrix or the restaurant by category matrix, and higher-order tensors, e.g., the "ratings" tensor of the form restaurant by meal by person. In this paper, we are particularly interested in fusing data sets with the goal of capturing their underlying latent structures. We formulate this problem as a coupled matrix and tensor factorization (CMTF) problem where heterogeneous data sets ...
Mazahery, Ali; Shabani, Mohsen Ostad
2012-12-01
In this article, a genetic algorithm (GA) is used to predict the mechanical properties and to optimize the process conditions of Al nanocomposites. An artificial intelligence method is also implemented as an assisting tool for engineering tasks of GAs. The principle of the survival of the fittest is applied to produce successively superior approximations to a solution. A population of points at each iteration is generated. The population approaches an optimal solution. The next population by computations that involve random choices is selected. The optimal volume percentage of SiC, cooling rate, and temperature gradient are computed to be 2.84 pct, 283 K/s (10 °C/s), 1273 K/m (1000 °C/m), respectively.
Optimization of the determinant of the Vandermonde matrix and related matrices
Energy Technology Data Exchange (ETDEWEB)
Lundengård, Karl; Österberg, Jonas; Silvestrov, Sergei [Division of Applied Mathematics, School of Education, Culture and Communication, Mälardalen University, Box 883, SE-721 23 Västerås (Sweden)
2014-12-10
Various techniques for interpolation of data, moment matching in stochastic applications and various methods in numerical analysis can be described using Vandermonde matrices. For this reason the properties of the determinant of the Vandermonde matrix and related matrices are interesting. Here the extreme points of the Vandermonde determinant, and related determinants, on some simple surfaces such as the unit sphere are analyzed, both numerically and analytically. Some results are also visualized in various dimensions. The extreme points of the Vandermonde determinant are also related to the roots of certain orthogonal polynomials such as the Hermite polynomials.
Buhrke, David; Velazquez Escobar, Francisco; Sauthof, Luisa; Wilkening, Svea; Herder, Nico; Tavraz, Neslihan N; Willoweit, Mario; Keidel, Anke; Utesch, Tillmann; Mroginski, Maria-Andrea; Schmitt, Franz-Josef; Hildebrandt, Peter; Friedrich, Thomas
2016-06-22
Bacteriophytochromes are promising tools for tissue microscopy and imaging due to their fluorescence in the near-infrared region. These applications require optimization of the originally low fluorescence quantum yields via genetic engineering. Factors that favour fluorescence over other non-radiative excited state decay channels are yet poorly understood. In this work we employed resonance Raman and fluorescence spectroscopy to analyse the consequences of multiple amino acid substitutions on fluorescence of the iRFP713 benchmark protein. Two groups of mutations distinguishing iRFP from its precursor, the PAS-GAF domain of the bacteriophytochrome P2 from Rhodopseudomonas palustris, have qualitatively different effects on the biliverdin cofactor, which exists in a fluorescent (state II) and a non-fluorescent conformer (state I). Substitution of three critical amino acids in the chromophore binding pocket increases the intrinsic fluorescence quantum yield of state II from 1.7 to 5.0% due to slight structural changes of the tetrapyrrole chromophore. Whereas these changes are accompanied by an enrichment of state II from ~40 to ~50%, a major shift to ~88% is achieved by remote amino acid substitutions. Additionally, an increase of the intrinsic fluorescence quantum yield of this conformer by ~34% is achieved. The present results have important implications for future design strategies of biofluorophores.
Buhrke, David; Velazquez Escobar, Francisco; Sauthof, Luisa; Wilkening, Svea; Herder, Nico; Tavraz, Neslihan N.; Willoweit, Mario; Keidel, Anke; Utesch, Tillmann; Mroginski, Maria-Andrea; Schmitt, Franz-Josef; Hildebrandt, Peter; Friedrich, Thomas
2016-01-01
Bacteriophytochromes are promising tools for tissue microscopy and imaging due to their fluorescence in the near-infrared region. These applications require optimization of the originally low fluorescence quantum yields via genetic engineering. Factors that favour fluorescence over other non-radiative excited state decay channels are yet poorly understood. In this work we employed resonance Raman and fluorescence spectroscopy to analyse the consequences of multiple amino acid substitutions on fluorescence of the iRFP713 benchmark protein. Two groups of mutations distinguishing iRFP from its precursor, the PAS-GAF domain of the bacteriophytochrome P2 from Rhodopseudomonas palustris, have qualitatively different effects on the biliverdin cofactor, which exists in a fluorescent (state II) and a non-fluorescent conformer (state I). Substitution of three critical amino acids in the chromophore binding pocket increases the intrinsic fluorescence quantum yield of state II from 1.7 to 5.0% due to slight structural changes of the tetrapyrrole chromophore. Whereas these changes are accompanied by an enrichment of state II from ~40 to ~50%, a major shift to ~88% is achieved by remote amino acid substitutions. Additionally, an increase of the intrinsic fluorescence quantum yield of this conformer by ~34% is achieved. The present results have important implications for future design strategies of biofluorophores. PMID:27329837
Lewis, Jared C.
2010-11-24
Made for each other: Combinatorial alanine substitution of active site residues in a thermostable cytochrome P450BM3 variant was used to generate an enzyme that is active with large substrates. Selective hydroxylation of methoxymethylated monosaccharides, alkaloids, and steroids was thus made possible (see Scheme). This approach could be useful for improving the activity of enzymes that show only limited activity with larger substrates. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Aubert, Y; Bourgerie, S; Meunier, L; Mayer, R; Roche, A C; Monsigny, M; Thuong, N T; Asseline, U
2000-02-01
A new deprotection procedure enables a medium scale preparation of phosphodiester and phosphor-othioate oligonucleotides substituted with a protected thiol function at their 5'-ends and an amino group at their 3'-ends in good yield (up to 72 OD units/micromol for a 19mer phosphorothioate). Syntheses of 3'-amino-substituted oligonucleotides were carried out on a modified support. A linker containing the thioacetyl moiety was manually coupled in two steps by first adding its phosphor-amidite derivative in the presence of tetrazole followed by either oxidation or sulfurization to afford the bis-derivatized oligonucleotide bound to the support. Deprotection was achieved by treating the fully protected oligonucleotide with a mixture of 2,2'-dithiodipyridine and concentrated aqueous ammonia in the presence of phenol and methanol. This proced-ure enables (i) cleavage of the oligonucleotide from the support, releasing the oligonucleotide with a free amino group at its 3'-end, (ii) deprotection of the phosphate groups and the amino functions of the nucleic bases, as well as (iii) transformation of the 5'-terminal S -acetyl function into a dithiopyridyl group. The bis-derivatized phosphorothioate oligomer was further substituted through a two-step procedure: first, the 3'-amino group was reacted with fluorescein isothiocyanate to yield a fluoresceinylated oligo-nucleotide; the 5'-dithio-pyridyl group was then -quantitatively reduced to give a free thiol group which was then substituted by reaction with an N alpha-bromoacetyl derivative of a signal peptide containing a KDEL sequence to afford a fluoresceinylated peptide-oligonucleotide conjugate.
Restricted strong convexity and weighted matrix completion: Optimal bounds with noise
Negahban, Sahand
2010-01-01
We consider the matrix completion problem under a form of row/column weighted entrywise sampling, including the case of uniform entrywise sampling as a special case. We analyze the associated random observation operator, and prove that with high probability, it satisfies a form of restricted strong convexity with respect to weighted Frobenius norm. Using this property, we obtain as corollaries a number of error bounds on matrix completion in the weighted Frobenius norm under noisy sampling and for both exact and near low-rank matrices. Our results are based on measures of the "spikiness" and "low-rankness" of matrices that are less restrictive than the incoherence conditions imposed in previous work. Our technique involves an $M$-estimator that includes controls on both the rank and spikiness of the solution, and we establish non-asymptotic error bounds in weighted Frobenius norm for recovering matrices lying with $\\ell_q$-"balls" of bounded spikiness. Using information-theoretic methods, we show that no algo...
Directory of Open Access Journals (Sweden)
SENTHIL KUMAR. M.P
2014-08-01
Full Text Available The Aluminum Hybrid Metal Matrix Composites (Al-HMMC are finding numerous applications in many areas like Automobile, Piston and Cylinder and Aerospace, etc. Adding a third element into the metal matrix composite makes it hybrid. The Reinforcement of SiC and Graphite used in this Al-HMMC improves its strength. The present investigation is to find the optimum machining parameter of CNC turning centre on Al-HMMC. The main objective is to find the optimum cutting parameters to achieve low value of surface roughness and high Material Removal Rate (MRR. The cutting parameters considered in this experimental investigation are cutting speed, feed rate and depth of cut. Taguchi L27 orthogonal array was chosen to conduct the experiments. Signal to Noise ratio (S/N and Analysis of Variance (ANOVA were used to analyze the effect of cutting parameters on surface roughness and MRR. The contribution by each cutting parameter to surface roughness and MRR was also determined.
Madsen, Jonas S; Lin, Yu-Cheng; Squyres, Georgia R; Price-Whelan, Alexa; de Santiago Torio, Ana; Song, Angela; Cornell, William C; Sørensen, Søren J; Xavier, Joao B; Dietrich, Lars E P
2015-12-01
As biofilms grow, resident cells inevitably face the challenge of resource limitation. In the opportunistic pathogen Pseudomonas aeruginosa PA14, electron acceptor availability affects matrix production and, as a result, biofilm morphogenesis. The secreted matrix polysaccharide Pel is required for pellicle formation and for colony wrinkling, two activities that promote access to O2. We examined the exploitability and evolvability of Pel production at the air-liquid interface (during pellicle formation) and on solid surfaces (during colony formation). Although Pel contributes to the developmental response to electron acceptor limitation in both biofilm formation regimes, we found variation in the exploitability of its production and necessity for competitive fitness between the two systems. The wild type showed a competitive advantage against a non-Pel-producing mutant in pellicles but no advantage in colonies. Adaptation to the pellicle environment selected for mutants with a competitive advantage against the wild type in pellicles but also caused a severe disadvantage in colonies, even in wrinkled colony centers. Evolution in the colony center produced divergent phenotypes, while adaptation to the colony edge produced mutants with clear competitive advantages against the wild type in this O2-replete niche. In general, the structurally heterogeneous colony environment promoted more diversification than the more homogeneous pellicle. These results suggest that the role of Pel in community structure formation in response to electron acceptor limitation is unique to specific biofilm models and that the facultative control of Pel production is required for PA14 to maintain optimum benefit in different types of communities.
Applications of multiple-constraint matrix updates to the optimal control of large structures
Smith, S. W.; Walcott, B. L.
1992-01-01
Low-authority control or vibration suppression in large, flexible space structures can be formulated as a linear feedback control problem requiring computation of displacement and velocity feedback gain matrices. To ensure stability in the uncontrolled modes, these gain matrices must be symmetric and positive definite. In this paper, efficient computation of symmetric, positive-definite feedback gain matrices is accomplished through the use of multiple-constraint matrix update techniques originally developed for structural identification applications. Two systems were used to illustrate the application: a simple spring-mass system and a planar truss. From these demonstrations, use of this multiple-constraint technique is seen to provide a straightforward approach for computing the low-authority gains.
Directory of Open Access Journals (Sweden)
S.Dharmalingam
2014-05-01
Full Text Available This paper investigates the influence of the process parameters like machining voltage, electrolyte concentration, frequency on the over cut and Material Removal Rate (MRR through taguchi methodology and grey relational analysis. This paper discusses a methodology for the optimization of the machining parameters on drilling of Al - 6% Gr Metal Matrix composites using Electrochemical Micro Machining (EMM. Based on the analysis, optimum levels of parameters were determined and the same to validate through the confirmation test. Experimental results are in close agreement with the developed model. The confirmation results reveal that, there is considerable improvement in Material Removal Rate, Overcut, Grey relational grade are improved by 08.33 %, 41.17 % and 81.77 % respectively. It is observed that the machining performance can be effectively improved with respect to initial parametric setting.
Cozza, Dario; Ruiz, Carmen M; Duché, David; Giraldo, Sergio; Saucedo, Edgardo; Simon, Jean Jacques; Escoubas, Ludovic
2016-09-01
The fast and computationally inexpensive Modified Transfer Matrix Method (MTM) is employed to simulate the optical response of kesterite Cu2ZnSnSe4 solar cells. This method can partially take into account the scattering effects due to roughness at the interfaces between the layers of the stack. We analyzed the optical behavior of the whole cell structure by varying the thickness of the TCO layer (iZnO + ITO) between 50 and 1200 nm and the buffer CdS layer between 0 and 100 nm. We propose optimal combinations of the TCO/CdS thicknesses that can locally maximize the device photocurrent. We provide experimental data that qualitatively confirm our theoretical predictions.
Directory of Open Access Journals (Sweden)
M. Soumya
2014-01-01
Full Text Available In the present study, an effort was made to formulate and evaluate matrix tablets of tarogum utilizing metaprolol succinate as the model drug. 3 2 full optimization procedure was adopted where two factors are studied at three levels. The amount of taro gum (X1 and polyvinylpyrrolidone (PVP K30 (X2 were selected as independent variables. The time required for 90% of drug release was selected as the dependent variable. Tablets were prepared by direct compression and were evaluated for various post compression parameters such as tablet hardness, friability, weight variation, drug content and in vitro dissolution. The results were found to be within the acceptable limits. The release exponent (n lies between 0.416 and 0.584 indicating drug release from the matrix tablets may be fickian or non-fickian (anomalous depending upon the concentration of natural polymer. T90 was 10.70, 11.20, 12.05, 12.66 h for B6, B7, B8 and B9 batches respectively showing overriding potential of taro gum, but still the effect of PVP K 30 is noteworthy. PVP K 30 has an indirect effect on all the factors by increasing tensile strength and making the tablet firm and intact.
Abdelfattah, Ahmad
2016-05-23
Simulations of many multi-component PDE-based applications, such as petroleum reservoirs or reacting flows, are dominated by the solution, on each time step and within each Newton step, of large sparse linear systems. The standard solver is a preconditioned Krylov method. Along with application of the preconditioner, memory-bound Sparse Matrix-Vector Multiplication (SpMV) is the most time-consuming operation in such solvers. Multi-species models produce Jacobians with a dense block structure, where the block size can be as large as a few dozen. Failing to exploit this dense block structure vastly underutilizes hardware capable of delivering high performance on dense BLAS operations. This paper presents a GPU-accelerated SpMV kernel for block-sparse matrices. Dense matrix-vector multiplications within the sparse-block structure leverage optimization techniques from the KBLAS library, a high performance library for dense BLAS kernels. The design ideas of KBLAS can be applied to block-sparse matrices. Furthermore, a technique is proposed to balance the workload among thread blocks when there are large variations in the lengths of nonzero rows. Multi-GPU performance is highlighted. The proposed SpMV kernel outperforms existing state-of-the-art implementations using matrices with real structures from different applications. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.
Total variation optimization for imaging through turbid media with transmission matrix
Gong, Changmei; Shao, Xiaopeng; Wu, Tengfei; Liu, Jietao; Zhang, Jianqi
2016-12-01
With the transmission matrix (TM) of the whole optical system measured, the image of the object behind a turbid medium can be recovered from its speckle field by means of an image reconstruction algorithm. Instead of Tikhonov regularization algorithm (TRA), the total variation minimization by augmented Lagrangian and alternating direction algorithms (TVAL3) is introduced to recover object images. As a total variation (TV)-based approach, TVAL3 allows to effectively damp more noise and preserve more edges compared with TRA, thus providing more outstanding image quality. Different levels of detector noise and TM-measurement noise are successively added to analyze the antinoise performance of these two algorithms. Simulation results show that TVAL3 is able to recover more details and suppress more noise than TRA under different noise levels, thus providing much more excellent image quality. Furthermore, whether it be detector noise or TM-measurement noise, the reconstruction images obtained by TVAL3 at SNR=15 dB are far superior to those by TRA at SNR=50 dB.
Miyazawa, Arata; Hong, Young-Joo; Makita, Shuichi; Kasaragod, Deepa K.; Miura, Masahiro; Yasuno, Yoshiaki
2017-02-01
Local statistics are widely utilized for quantification and image processing of OCT. For example, local mean is used to reduce speckle, local variation of polarization state (degree-of-polarization-uniformity (DOPU)) is used to visualize melanin. Conventionally, these statistics are calculated in a rectangle kernel whose size is uniform over the image. However, the fixed size and shape of the kernel result in a tradeoff between image sharpness and statistical accuracy. Superpixel is a cluster of pixels which is generated by grouping image pixels based on the spatial proximity and similarity of signal values. Superpixels have variant size and flexible shapes which preserve the tissue structure. Here we demonstrate a new superpixel method which is tailored for multifunctional Jones matrix OCT (JM-OCT). This new method forms the superpixels by clustering image pixels in a 6-dimensional (6-D) feature space (spatial two dimensions and four dimensions of optical features). All image pixels were clustered based on their spatial proximity and optical feature similarity. The optical features are scattering, OCT-A, birefringence and DOPU. The method is applied to retinal OCT. Generated superpixels preserve the tissue structures such as retinal layers, sclera, vessels, and retinal pigment epithelium. Hence, superpixel can be utilized as a local statistics kernel which would be more suitable than a uniform rectangle kernel. Superpixelized image also can be used for further image processing and analysis. Since it reduces the number of pixels to be analyzed, it reduce the computational cost of such image processing.
Ivanov, A. S.; Matvienko, V. P.; Oshmarin, D. A.; Sevodina, N. V.; Yurlov, M. A.; Yurlova, N. A.
2016-05-01
We consider elastoplastic systems which are piecewise homogeneous bodies composed of piezoelectric elements some of which have piezoelectrical properties. Electric series circuits consisting of resistors, capacitors, and inductance coils are applied to piezoelectric elements through the electrode coating on the body surface. The goal of the study is to develop efficient methods of mathematical modelling for determining the parameters of elements of the external electric circuit, which ensure, at prescribed resonance frequencies, the maximum damping properties of electroelastic bodies with external electric circuits. To choose effective circuits for solving the problem posed above, we suggest to pose the problem of natural vibrations of elastic bodies whose elements exhibit piezoeffect and have external electric circuits.As the most efficient approaches for calculating the electric circuit parameters necessary for the maximal damping, we propose some versions of equivalent circuits, which can be used to substitute elastic systems with piezoelectric elements. The most reliable equivalent substitution circuits are justified on the basis of the proposed problem of natural vibrations. Numerical results are obtained for a cantilever plate with a piezoelement connected through the electrode coated surface with a series electric circuit consisting of resistors, capacitors and inductance coils.
Optimal Model for Velocity Strength Training Methods for Boy Sprinters Base on Fuzzy Matrix
Directory of Open Access Journals (Sweden)
Juntao Sun
2013-04-01
Full Text Available With literature consultation, Delphi method, fuzzy mathematics, experimental method and mathematical statistics method, from multi viewpoints, this study analyzes the velocity strength quality of boy two-level sprinters in quality and quantity. The result shows, with fuzzy mathematics, we can judge the relative degree between velocity strength and various methods, with quantitative disposal to analyze quantitatively, which has certain theoretic significance; according to analysis of fuzzy relation and corresponding relation, build the classification figure for velocity strength training method for boy sprinters; relative data proof, the optimal organization of different training methods can outstand the training specialization and save time and energy, so as to supplement the special training theories, to provide theoretic references and practical instructions for most coaches’ training processes, to improve the efficiency.
Godfrey, Devon J; McAdams, H P; Dobbins, James T
2006-03-01
Matrix inversion tomosynthesis (MITS) uses linear systems theory, along with a priori knowledge of the imaging geometry, to deterministically distinguish between true structure and overlying tomographic blur in a set of conventional tomosynthesis planes. In this paper we examine the effect of total scan angle (ANG), number of input projections (N), and plane separation/number of reconstructed planes (NP) on the MITS impulse response (IR) and modulation transfer function (MTF), with the purpose of optimizing MITS imaging of the chest. MITS IR and MTF data were generated by simulating the imaging of a very thin wire, using various combinations of ANG, N, and NP. Actual tomosynthesis data of an anthropomorphic chest phantom were acquired with a prototype experimental system, using the same imaging parameter combinations as those in the simulations. Thoracic projection data from two human subjects were collected for corroboration of the system response analysis in vivo. Results suggest that ANG=20 degrees, N=71, NP=69 is the optimal combination for MITS chest imaging given the inherent constraints of our prototype system. MITS chest data from human subjects demonstrates that the selected imaging strategy can effectively produce high-quality MITS thoracic images in vivo.
Zirehpour, Alireza; Rahimpour, Ahmad; Jahanshahi, Mohsen; Peyravi, Majid
2014-01-01
Olive oil mill wastewater (OMW) is a concentrated effluent with a high organic load. It has high levels of organic chemical oxygen demand (COD) and phenolic compounds. This study presents a unique process to treat OMW. The process uses ultrafiltration (UF) membranes modified by a functionalized multi wall carbon nano-tube (F-MWCNT). The modified tube has an inner diameter of 15-30 nm and is added to the OMW treatment process to improve performance of the membrane. Tests were done to evaluate the following operating parameters of the UF system; pressure, pH and temperature; also evaluated parameters of permeate flux, flux decline, COD removal and total phenol rejection. The Taguchi robust design method was applied for an optimization evaluation of the experiments. Variance (ANOVA) analysis was used to determine the most significant parameters affecting permeate flux, flux decline, COD removal and total phenols rejection. Results demonstrated coagulation and pH as the most important factors affecting permeate flux of the UF. Moreover, pH and F-MWCNT UF had significant positive effects on flux decline, COD removal and total phenols rejection. Based on the optimum conditions determined by the Taguchi method, evaluations for permeate flux tests; flux decline, COD removal and total phenols rejection were about 21.2 (kg/m(2) h), 12.6%, 72.6% and 89.5%, respectively. These results were in good agreement with those predicted by the Taguchi method (i.e.; 22.8 (kg/m(2) h), 11.9%, 75.8 and 94.7%, respectively). Mechanical performance of the membrane and its application for high organic wastewater treatment were determined as strong.
Energy Technology Data Exchange (ETDEWEB)
Carrasco, C., E-mail: ccarrascoc@udec.cl [Department of Materials Engineering, University of Concepción, Edmundo Larenas 270, Concepción (Chile); Inzunza, G.; Camurri, C.; Rodríguez, C. [Department of Materials Engineering, University of Concepción, Edmundo Larenas 270, Concepción (Chile); Radovic, L. [Department of Chemical Engineering, University of Concepción, Edmundo Larenas 129, Concepción (Chile); Department of Energy and Geo-Environmental Engineering, Pennsylvania State University, University Park, PA 16802 (United States); Soldera, F.; Suarez, S. [Department of Materials Science, Saarland University, Campus D3.3, 66123 Saarbrücken (Germany)
2014-11-03
The collection of used beverage cans is limited in countries where they are not fabricated; their low value does not justify the extra charge of exporting them for further processing. To address this increasingly serious problem, here we optimize the properties of an aluminum metal matrix composite (Al-MMC) obtained through direct fusion of beverage cans by using the slag generated in the melting process as reinforcement. This method consists of a modified rheocasting process followed by thixoforming. Our main operational variable is the shear rate applied to a semi-solid bath, subsequent to which a suitable heat treatment (T8) is proposed to improve the mechanical properties. The microstructure, the phases obtained and their effect on composite mechanical properties are analyzed. The composite material produced has, under the best conditions, a yield stress of 175 MPa and a tensile strength of 273 MPa. These results demonstrate that the proposed process does indeed transform the used beverage cans into promising composite materials, e.g., for structural applications.
TTCAN系统矩阵的优化算法%Optimization Algorithm of System Matrix for TTCAN (Network)
Institute of Scientific and Technical Information of China (English)
李运生; 窦金生
2012-01-01
To meet the teal-time requirements for periodic and non-periodic information of TICAN, the method based on dynamic priority of "right" to improve the real-time performance of non-periodic information in arbitration windows is proposed. Letter encoding genetic algorithm is introduced in the method to optimize the time scheduling for system matrix. Specific calculation method and procedures are given. The test shows that this method satisfies the requirements for real-time performance of all the information in the network.%为满足TTCAN的非周期和周期信息的实时性要求,提出了一种采用“权”的动态优先级提升算法.该算法用来提高仲裁窗中非周期信息的实时性.算法引入字母编码方式的遗传算法对系统矩阵时间调度表进行优化,并给出具体的计算方法和步骤.试验表明,该算法可以很好地满足网络中各信息的实时性要求.
Directory of Open Access Journals (Sweden)
Gangadharudu Talla
2015-09-01
Full Text Available Low material removal rate (MRR and high surface roughness values hinder large-scale application of electro discharge machining (EDM in the fields like automobile, aerospace and medical industry. In recent years, however, EDM has gained more significance in these industries as the usage of difficult-to-machine materials including metal matrix composites (MMCs increased. In the present work, an attempt has been made to fabricate and machine aluminum/alumina MMC using EDM by adding aluminum powder in kerosene dielectric. Results showed an increase in MRR and decrease in surface roughness (Ra compared to those for conventional EDM. Semi empirical models for MRR and Ra based on machining parameters and important thermo physical properties were established using a hybrid approach of dimensional and regression analysis. A multi response optimization was also performed using principal component analysis-based grey technique (Grey-PCA to determine optimum settings of process parameters for maximum MRR and minimum Ra within the experimental range. The recommended setting of process parameters for the proposed process has been found to be powder concentration (Cp = 4 g/l, peak current (Ip = 3 A, pulse on time (Ton = 150 μs and duty cycle (Tau = 85%.
Choi, Benjamin B.; Duffy, Kirsten; Kauffman, Jeffrey L.; Kray, Nicholas
2012-01-01
NASA Glenn Research Center, in collaboration with GE Aviation, has begun the development of a smart adaptive structure system with piezoelectric (PE) transducers to improve composite fan blade damping at resonances. Traditional resonant damping approaches may not be realistic for rotating frame applications such as engine blades. The limited space in which the blades reside in the engine makes it impossible to accommodate the circuit size required to implement passive resonant damping. Thus, a novel digital shunt scheme has been developed to replace the conventional electric passive shunt circuits. The digital shunt dissipates strain energy through the load resistor on a power amplifier. General Electric (GE) designed and fabricated a variety of polymer matrix fiber composite (PMFC) test specimens. Investigating the optimal topology of PE sensors and actuators for each test specimen has revealed the best PE transducer location for each target mode. Also a variety of flexible patches, which can conform to the blade surface, have been tested to identify the best performing PE patch. The active damping control achieved significant performance at target modes. This work has been highlighted by successful spin testing up to 5000 rpm of subscale GEnx composite blades in Glenn s Dynamic Spin Rig.
Rana, Vikas; Babita, Kumar; Goyal, Dinesh; Gorea, Rakesh; Tiwary, Ashok
2004-12-01
The present investigation is aimed at preparing chitosan films capable of simulating the flux of modal drugs, 5-fluorouracil (5-FU) and indomethacin (INDO), across rat, rabbit and human cadaver epidermal sheets. Application of statistical design revealed that the concentration of chitosan, crosslinking time and concentration of crosslinking agent significantly influenced the in vitro flux of 5-FU and INDO across chitosan films. Multiple linear regression revealed a linear influence of all these active variables on 5-FU and INDO flux. It was deduced from atomic absorption spectroscopic analyses, DSC and IR spectroscopic data that 5% (m/V) sodium tripolyphosphate (NaTPP) produced optimum crosslinking of chitosan films. The in vitro permeation of both 5-FU and INDO across optimized film formulations was found to be comparable to that obtained across rat, rabbit and human epidermal sheets. These results indicate that optimized chitosan films have a potential to be developed as a substitute for animal and human cadaver epidermal sheets for preliminary in vitro permeation studies.
代可可脂花生夹心糖制作工艺优化%Optimization of Ingredient Composition for Cocoa Butter Substitute/Peanut Bonbons
Institute of Scientific and Technical Information of China (English)
曾庆梅; 靳靖; 魏春燕; 吴聪; 黄博英
2012-01-01
以花生糖为糖芯,代可可脂为主要包衣材料,制作代可可脂巧克力花生夹心糖。利用响应面分析法优化糖芯制作工艺。根据Box-Behnken中心组合试验设计原理对工艺条件进行优化,在分析各因素显著性及其交互作用的基础上,得出花生糖芯口感最佳配方为：糖芯的最佳配料为白糖-淀粉糖浆-花生粉末-猪油（添加量质量配比为3.33：4.02：7.24：1）,包衣材料的最佳配料为白糖30%、乳化剂0.5%、代可可脂-可可粉8：1（m/m）;包衣厚度1.4mm,包衣温度50℃。%In this study,cocoa butter substitute/peanut bonbons were made with peanut sugar as the core and cocoa butter substitute as the main coating material.Response surface methodology was used to optimize the ingredient composition of bonbon core and coating based on a central composite design.According the results of significance analysis of various variables and their interactions,the optimal bonbon core was composed of sugar,starch syrup,peanut powder and lard at a mass ratio of 3.33：4.02：7.24：1,and the optimal bonbon coating was composed of 30% sugar,0.5% emulsifier,and cocoa butter substitute：cocoa powder at a mass ratio of 8：1,1.4 mm in thickness,and formed at 50 ℃.
Detailed assessment of homology detection using different substitution matrices
Institute of Scientific and Technical Information of China (English)
LI Jing; WANG Wei
2006-01-01
Homology detection plays a key role in bioinformatics, whereas substitution matrix is one of the most important components in homology detection. Thus, besides the improvement of alignment algorithms, another effective way to enhance the accuracy of homology detection is to use proper substitution matrices or even construct new matrices.A study on the features of various matrices and on the comparison of the performances between different matrices in homology detection enable us to choose the most proper or optimal matrix for some specific applications. In this paper, by taking BLOSUM matrices as an example, some detailed features of matrices in homology detection are studied by calculating the distributions of numbers of recognized proteins over different sequence identities and sequence lengths. Our results clearly showed that different matrices have different preferences and abilities to the recognition of remote homologous proteins. Furthermore, detailed features of the various matrices can be used to improve the accuracy of homology detection.
Energy Technology Data Exchange (ETDEWEB)
Kojima, Masazumi; Nakagami, Hiroaki [Daiichi Pharmaceutical Co., Tokyo (Japan). Pharmaceutical Technology Research Lab.
2002-12-01
The water mobility and diffusivity in the gel-layer of hydrating low-substituted hydroxypropyl cellulose (LH41) tablets with or without a drug were investigated by magnetic resonance imaging (MRI) and compared with those properties in the gel-layer of hydroxypropylmethyl cellulose (HPMC) and hydroxypropyl cellulose (HPC) tablets. For this purpose, a localized image-analysis method was newly developed, and the spin-spin relaxation time (T{sub 2}) and apparent self-diffusion coefficient (ADC) of water in the gel-layer were visualized in one-dimensional maps. Those maps showed that the extent of gel-layer growth in the tablets was in the order of HPC>HPMC>>LH41, and there was a water mobility gradient across the gel-layers of all three tablet formulations. The T{sub 2} and ADC in the outer parts of the gel-layers were close to those of free water. In contrast, these values in the inner parts of the gel-layer decreased progressively; suggesting that the water mobility and diffusivity around the core interface were highly restricted. Furthermore, the correlation between the T{sub 2} of {sup 1}H proton in the gel-layer of the tablets and the drug release rate from the tablets was observed. (author)
Gurpreetarora; Malik, Karan; Rana, Vikas; Singh, Inderbir
2012-01-01
The objective of this study was to extend the GI residence time of the dosage form and to control the release of domperidone using directly compressible sustained release mucoadhesive matrix (SRMM) tablets. A 2-factor centre composite design (CCD) was employed to study the influence of independent variables like gum ghatti (GG) (X1) and hydroxylpropylmethyl cellulose K 15M (HPMC K 15M) (X2) on dependent variable like mucoadhesive strength, tensile strength, release exponent (n), t50 (time for 50% drug release), rel(10 h) (release after 10 h) and rel(18 h) (release after 18 h). Tablets were prepared by direct compression technology and evaluated for tablet parametric test (drug assay, diameter, thickness, hardness and tensile strength), mucoadhesive strength (using texture analyzer) and in vitro drug release studies. The tensile strength and mucoadhesive strength were found to be increased from 0.665 +/- 0.1 to 1.591 +/- 0.1 MN/cm2 (Z1 to Z9) and 10.789 +/- 0.985 to 50.924 +/- 1.150 N (Z1 to Z9), respectively. The release kinetics follows first order and Hixson Crowell equation indicating drug release following combination of diffusion and erosion. The n varies between 0.834 and 1.273, indicating release mechanism shifts from non fickian (anomalous release) to super case II, which depict that drug follows multiple drug release mechanism. The t50 time was found to increase from 5 +/- 0.12 to 11.4 +/- 0.14 h (Z1 to Z9) and release after 10 and 18 h decreases with increasing concentration of both polymers concluding with release controlling potential of polymers. The accelerated stability studies were performed on optimized formulation as per ICH guideline and the result showed that there was no significant change in tensile strength, mucoadhesive strength and drug assay.
Troiano, Giuseppe; Laino, Luigi; Zhurakivska, Khrystyna; Cicciù, Marco; Lo Muzio, Lorenzo; Lo Russo, Lucio
2017-07-01
In order to enhance clinical improvement of intrabony defects, the addition of enamel matrix derivatives (EMD) to bone substitues (BS) has been investigated. The aim of this systematic review is to figure out whether such a combination, in comparison to the treatment with BS alone has beneficial effects on the following outcomes: clinical attachment level (CAL) gain, probing depth (PD) reduction and recession (REC). Electronic databases (PUBMED, SCOPUS, EBSCO Host Research Databases and Web of Knowledge) were searched for randomized controlled trials in humans addressing the use of a combination of BS and EMD versus a control group with BS alone for the treatment of intrabony defects, with a minimum of 6 months of follow-up; meta-analysis and trial sequential analysis were then performed. From a total of 1,197 records screened by title and abstract, nine studies were read full-text and five out of them included in the meta-analysis. No significant differences have been demonstrated both for CAL gain, PD reduction and REC between test and control groups. In the treatment of intrabony defects, the addition of EMD to BS seems to be not beneficial in terms of CAL gain, PD reduction and REC changes. However, such results should be considered with caution because of the small number of studies included in the meta-analysis and their heterogeneity. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
Rutherford, Daniel Edwin
2013-01-01
Classic monograph, suitable for advanced undergraduates and graduate students. Topics include calculus of permutations and tableaux, semi-normal representation, orthogonal and natural representations, group characters, and substitutional equations. 1968 edition.
... drinks. You may also have heard them called "artificial sweeteners" or "non-caloric sweeteners." They can be used ... of nutrition for your body.What sugar substitutes/artificial sweeteners are approved by the FDA?The following sugar ...
哈尔滨红肠中脂肪丁模拟替代物%Formulation and Optimization of Fat Substitute Used in Harbin Red Sausage
Institute of Scientific and Technical Information of China (English)
张根生; 姚烨; 姜艳; 张毅超; 程健博; 常虹
2015-01-01
以魔芋、卡拉胶、菊粉、聚葡萄糖为主要原料制得脂肪丁替代物，代替红肠中的脂肪丁，降低红肠中的脂肪含量，通过单因素和正交试验，以感官评分和质构特性为指标，确定脂肪丁替代物的最佳配方（以水为基础）：魔芋胶添加量2.5 g/100 mL、卡拉胶添加量1.25 g/100 mL、菊粉添加量1.00 g/100 mL、聚葡萄糖添加量0.75 g/100 mL、Ca(OH)2添加量为0.06 g/100 mL、猪肉精粉添加量3 g/100 mL；脂肪丁模拟物的替代量为100%（以脂肪丁的总量计），在此条件下制成的红肠脂肪含量低，口感良好。%Fat substitute consisting of konjac, carrageenan, inulin and glucose was used to replace the fat dices in Harbin red sausages for fat reduction. As established by the combined use of single factor and orthogonal array experiments based on sensory evaluation and texture characteristics, the optimal formulation was composed of (in 100 mL of water) 2.5 g of konjac gum, 1.25 g of carrageenan, 1.00 g of inulin, 0.75 g of polydextrose, 0.06 g of Ca (OH)2, and 3 g of pork powder. Fat-reduced red sausage with a good taste was obtained when 100% fat replacement with the substitute was applied.
Optimization of Matrix Formula for Qingre Zhitong Cataplasm%清热止痛巴布剂基质处方的优化
Institute of Scientific and Technical Information of China (English)
范彦博; 王薇; 杜雪光; 王进军
2016-01-01
目的：：优选清热止痛巴布剂的基质处方。方法：以持黏力和综合感官的综合评分为考察指标，选取聚丙烯酸钠、羧甲基纤维素钠、水合氯化铝和甘油的配比为考察因素，采用正交试验优选复方清热止痛巴布剂的基质处方。结果：清热止痛巴布剂的最佳基质处方配比为：聚丙烯酸钠-羧甲基纤维素钠-水合氯化铝-甘油=14∶1∶1∶120。结论：按优选的最佳基质处方制得的清热止痛巴布剂具有良好的持黏力与综合感官，工艺参数稳定可行。%Objective:To optimize the matrix formula of Qingre Zhitong cataplasm. Methods:An orthogonal test was performed to study the matrix formula of Qingre Zhitong cataplasm with the comprehensive score of continued adhesion and integrated sensory as the evaluation indices and the ratio of sodium polyacrylate, carboxymethylcellulose sodium, aluminum chloride hydrate and glycerin as the influencing factor. Results:The optimal matrix formula of Qingre Zhitong cataplasm was as follows: the ratio of sodium polyacrylate, carboxymethylcellulose sodium, aluminum chloride hydrate and glycerin was 14 ∶1 ∶1 ∶120. Conclusion: Qingre Zhitong cataplasm prepared with the optimal matrix formula has good continued adhesion and integrated sensory, and the process parameters are stable and feasible.
Revisiting amino acid substitution matrices for identifying distantly related proteins.
Yamada, Kazunori; Tomii, Kentaro
2014-02-01
Although many amino acid substitution matrices have been developed, it has not been well understood which is the best for similarity searches, especially for remote homology detection. Therefore, we collected information related to existing matrices, condensed it and derived a novel matrix that can detect more remote homology than ever. Using principal component analysis with existing matrices and benchmarks, we developed a novel matrix, which we designate as MIQS. The detection performance of MIQS is validated and compared with that of existing general purpose matrices using SSEARCH with optimized gap penalties for each matrix. Results show that MIQS is able to detect more remote homology than the existing matrices on an independent dataset. In addition, the performance of our developed matrix was superior to that of CS-BLAST, which was a novel similarity search method with no amino acid matrix. We also evaluated the alignment quality of matrices and methods, which revealed that MIQS shows higher alignment sensitivity than that with the existing matrix series and CS-BLAST. Fundamentally, these results are expected to constitute good proof of the availability and/or importance of amino acid matrices in sequence analysis. Moreover, with our developed matrix, sophisticated similarity search methods such as sequence-profile and profile-profile comparison methods can be improved further. Newly developed matrices and datasets used for this study are available at http://csas.cbrc.jp/Ssearch/.
Boisson, F.; Bekaert, V.; Reilhac, A.; Wurtz, J.; Brasse, D.
2015-03-01
In SPECT imaging, improvement or deterioration of performance is mostly due to collimator design. Classical SPECT systems mainly use parallel hole or pinhole collimators. Rotating slat collimators (RSC) can be an interesting alternative to optimize the tradeoff between detection efficiency and spatial resolution. The present study was conducted using a RSC system for small animal imaging called CLiR. The CLiR system was used in planar mode only. In a previous study, planar 2D projections were reconstructed using the well-known filtered backprojection algorithm (FBP). In this paper, we investigated the use of the statistical reconstruction algorithm maximum likelihood expectation maximization (MLEM) to reconstruct 2D images with the CLiR system using a probability matrix calculated using an analytic approach. The primary objective was to propose a method to quickly generate a light system matrix, which facilitates its handling and storage, while providing accurate and reliable performance. Two other matrices were calculated using GATE Monte Carlo simulations to investigate the performance obtained using the matrix calculated analytically. The first matrix calculated using GATE took all the physics processes into account, where the second did not consider for the scattering, as the analytical matrix did not take this physics process into account either. 2D images were reconstructed using FBP and MLEM with the three different probability matrices. Both simulated and experimental data were used. A comparative study of these images was conducted using different metrics: the modulation transfert function, the signal-to-noise ratio and quantification measurement. All the results demonstrated the suitability of using a probability matrix calculated analytically. It provided similar results in terms of spatial resolution (about 0.6 mm with differences image.
Directory of Open Access Journals (Sweden)
Carlo Maiorana
2016-01-01
Full Text Available The reconstruction of the atrophic alveolar ridges for implant placement is today a common procedure in dentistry daily practice. The surgical reconstruction provides for the optimization of the supporting bone for the implants and a restoration of the amount of keratinized gingiva for esthetic and functional reasons. In the past, tissue regeneration has been performed with autogenous bone and free gingival or connective tissue grafts. Nowadays, bone substitutes and specific collagen matrix allow for a complete restoration of the atrophic ridge without invasive harvesting procedures. A maxillary reconstruction of an atrophic ridge by means of tissue substitutes and its histological features are then presented.
Energy Technology Data Exchange (ETDEWEB)
1990-01-01
The DOE Environmental Restoration and Waste Management Office of Technology Development and the Air Force Engineering and Services Center convened the First Annual International Workshop on Solvent Substitution on December 4--7, 1990. The primary objectives of this joint effort were to share information and ideas among attendees in order to enhance the development and implementation of required new technologies for the elimination of pollutants associated with industrial use of hazardous and toxic solvents; and to aid in accelerating collaborative efforts and technology transfer between government and industry for solvent substitution. There were workshop sessions focusing on Alternative Technologies, Alternative Solvents, Recovery/Recycling, Low VOC Materials and Treatment for Environmentally Safe Disposal. The 35 invited papers presented covered a wide range of solvent substitution activities including: hardware and weapons production and maintenance, paint stripping, coating applications, printed circuit boards, metal cleaning, metal finishing, manufacturing, compliance monitoring and process control monitoring. This publication includes the majority of these presentations. In addition, in order to further facilitate information exchange and technology transfer, the US Air Force and DOE solicited additional papers under a general Call for Papers.'' These papers, which underwent review and final selection by a peer review committee, are also included in this combined Proceedings/Compendium. For those involved in handling, using or managing hazardous and toxic solvents, this document should prove to be a valuable resource, providing the most up-to-date information on current technologies and practices in solvent substitution. Individual papers are abstracted separated.
Directory of Open Access Journals (Sweden)
Panagiotis Maghsoudlou
Full Text Available Hepatic tissue engineering using decellularized scaffolds is a potential therapeutic alternative to conventional transplantation. However, scaffolds are usually obtained using decellularization protocols that destroy the extracellular matrix (ECM and hamper clinical translation. We aim to develop a decellularization technique that reliably maintains hepatic microarchitecture and ECM components. Isolated rat livers were decellularized by detergent-enzymatic technique with (EDTA-DET or without EDTA (DET. Histology, DNA quantification and proteomics confirmed decellularization with further DNA reduction with the addition of EDTA. Quantification, histology, immunostaining, and proteomics demonstrated preservation of extracellular matrix components in both scaffolds with a higher amount of collagen and glycosaminoglycans in the EDTA-DET scaffold. Scanning electron microscopy and X-ray phase contrast imaging showed microarchitecture preservation, with EDTA-DET scaffolds more tightly packed. DET scaffold seeding with a hepatocellular cell line demonstrated complete repopulation in 14 days, with cells proliferating at that time. Decellularization using DET preserves microarchitecture and extracellular matrix components whilst allowing for cell growth for up to 14 days. Addition of EDTA creates a denser, more compact matrix. Transplantation of the scaffolds and scaling up of the methodology are the next steps for successful hepatic tissue engineering.
DEFF Research Database (Denmark)
Hansen, Kristoffer Arnsfelt; Ibsen-Jensen, Rasmus; Podolskii, Vladimir V.;
2013-01-01
For matrix games we study how small nonzero probability must be used in optimal strategies. We show that for image win–lose–draw games (i.e. image matrix games) nonzero probabilities smaller than image are never needed. We also construct an explicit image win–lose game such that the unique optimal...
DEFF Research Database (Denmark)
Hansen, Kristoffer Arnsfelt; Ibsen-Jensen, Rasmus; Podolskii, Vladimir V.
2013-01-01
For matrix games we study how small nonzero probability must be used in optimal strategies. We show that for image win–lose–draw games (i.e. image matrix games) nonzero probabilities smaller than image are never needed. We also construct an explicit image win–lose game such that the unique optimal...
Directory of Open Access Journals (Sweden)
Jasper Killat
2013-07-01
Full Text Available New skin substitutes for burn medicine or reconstructive surgery pose an important issue in plastic surgery. Matriderm® is a clinically approved three-dimensional bovine collagen-elastin matrix which is already used as a dermal substitute of full thickness burn wounds. The drawback of an avital matrix is the limited integration in full thickness skin defects, depending on the defect size. To further optimize this process, Matriderm® has also been studied as a matrix for tissue engineering of skin albeit long-term cultivation of the matrix with cells has been difficult. Cells have generally been seeded onto the matrix with high cell loss and minimal time-consuming migration. Here we developed a cell seeded skin equivalent after microtransfer of cells directly into the matrix. First, cells were cultured, and microinjected into Matriderm®. Then, cell viability in the matrix was determined by histology in vitro. As a next step, the skin substitute was applied in vivo into a full thickness rodent wound model. The wound coverage and healing was observed over a period of two weeks followed by histological examination assessing cell viability, proliferation and integration into the host. Viable and proliferating cells could be found throughout the entire matrix. The presented skin substitute resembles healthy skin in morphology and integrity. Based on this study, future investigations are planned to examine behaviour of epidermal stem cells injected into a collagen-elastin matrix under the aspects of establishment of stem cell niches and differentiation.
Verrillo, Ronald T.
The idea that the cutaneous surface may be employed as a substitute for the eyes and ears is by no means a modern notion. Although the sense of touch has long been considered as a surrogate for both the visual and auditory modalities, the focus of this chapter will be on the efforts to develop a tactile substitute for hearing, especially that of human speech. The visual system is our primary means of processing information about environmental space such as orientation, distance, direction and size. It is much less effective in making temporal discriminations. The auditory system is unparalleled in processing information that involves rapid sequences of temporal events, such as speech and music. The tactile sense is capable of processing both spatial and temporal information although not as effective in either domain as the eye or the ear.
Dari-Mattiacci, G.; Parisi, F.; Heller, M.
2009-01-01
The presence of multiple sellers in the provision of (nonsubstitutable) complementary goods leads to outcomes that are worse than those generated by a monopoly (with a vertically integrated production of complements), a problem known in the economic literature as complementary oligopoly and recently popularized in the legal literature as the tragedy of the anticommons. We ask the following question: how many substitutes for each complement are necessary to render the presence of multiple sell...
Shiino, Kai; Iwao, Yasunori; Miyagishima, Atsuo; Itai, Shigeru
2010-08-16
The purpose of the present study was to design and evaluate a novel wax matrix system containing various ratios of aminoalkyl methacrylate copolymer E (AMCE) and ethylcellulose (EC) as functional polymers in order to achieve the optimal acetaminophen (APAP) release rate for taste masking. A two factor, three level (3(2)) full factorial study design was used to optimize the ratios of AMCE and EC, and the release of APAP from the wax matrix was evaluated using a stationary disk in accordance with the paddle method. The disk was prepared by congealing glyceryl monostearate (GM), a wax with a low melting point, with various ratios of polymers and APAP. The criteria for release rate of APAP from the disk at pH 4.0 and pH 6.5 were calculated to be more than 0.5017 microg/(mlxmin) and less than 0.1414 microg/(mlxmin), respectively, under the assumption that the particle size of spherical matrix should be 100 microm. In multiple regression analysis, the release of APAP at pH 4.0 was found to increase markedly as the concentration of AMCE increased, whereas the release of APAP at pH 6.5 decreased as the EC concentration increased, even when a high level of AMCE was incorporated. Using principle component analysis, it was found that the viscosity of the matrix affects the pH-dependent release of APAP at pH 4.0 and pH 6.5. Furthermore, using multiple regression analysis, the optimum ratio of APAP:AMCE:EC:GM was found to be 30:7:10:53, and the release pattern of APAP from the optimum wax formulation nearly complied with the desired criteria. Therefore, the present study demonstrated that the incorporation of AMCE and EC into a wax matrix system enabled the appropriate release of APAP as a means of taste masking. Copyright (c) 2010 Elsevier B.V. All rights reserved.
Kasesaz, Y; Khalafi, H; Rahmani, F
2013-12-01
Optimization of the Beam Shaping Assembly (BSA) has been performed using the MCNP4C Monte Carlo code to shape the 2.45 MeV neutrons that are produced in the D-D neutron generator. Optimal design of the BSA has been chosen by considering in-air figures of merit (FOM) which consists of 70 cm Fluental as a moderator, 30 cm Pb as a reflector, 2mm (6)Li as a thermal neutron filter and 2mm Pb as a gamma filter. The neutron beam can be evaluated by in-phantom parameters, from which therapeutic gain can be derived. Direct evaluation of both set of FOMs (in-air and in-phantom) is very time consuming. In this paper a Response Matrix (RM) method has been suggested to reduce the computing time. This method is based on considering the neutron spectrum at the beam exit and calculating contribution of various dose components in phantom to calculate the Response Matrix. Results show good agreement between direct calculation and the RM method.
Directory of Open Access Journals (Sweden)
Sezgin Bakırdere
2013-01-01
Full Text Available Arsenic, lead, and cadmium were determined in tap and bottled water samples consumed in the west part of Turkey at trace levels. Graphite furnace atomic absorption spectrometry (GFAAS was used in all detections. All of the system parameters for each element were optimized to increase sensitivity. Pd-Mg mixture was selected as the best matrix modifier for As, while the highest signals were obtained for Pb and Cd in the case of Ni used as matrix modifier. Detection limits for As, Cd, and Pb were found to be 2.0, 0.036, and 0.25 ng/mL, respectively. 78 tap water and 17 different brands of bottled water samples were analyzed for their As, Cd, and Pb contents under the optimized conditions. In all water samples, concentration of cadmium was found to be lower than detection limits. Lead concentration in the samples analyzed varied between N.D. and 12.66 ± 0.68 ng/mL. The highest concentration of arsenic was determined as 11.54 ± 2.79 ng/mL. Accuracy of the methods was verified by using a certified reference material, namely, Trace Element in Water, 1643e. Results found for As, Cd, and Pb in reference materials were in satisfactory agreement with the certified values.
Energy Technology Data Exchange (ETDEWEB)
Priyadarshi, Devinder [DAV Institute of Engineering and Technology, Jalandhar (India); Sharma, Rajesh Kumar [Institute of Technology, Hamirpur (India)
2016-03-15
Aluminium matrix composites (AMCs) now hold a significant share of raw materials in many applications. It is of prime importance to study the machinability of such composites so as to enhance their applicability. Sufficient work has been done for studying the machining of AMCs with particle reinforcements of micron range. This paper presents the study of AMCs with particle reinforcement of under micron range i.e. nanoparticles. This paper brings out the results of an experimental investigation of type and weight percent of nanoparticles on the tangential cutting force during turning operation. SiC, Gr and SiC-Gr (in equal proportions) were used with Al-6061 alloy as the matrix phase. The results indicate that composites with SiC require greater cutting force followed by hybrid and then Gr. Increase in the weight percent also significantly affected the magnitude of cutting force. RSM was used first to design and analyze the experiments and then to optimize the turning process and obtain optimal conditions of weight and type of reinforcements for turning operation.
Directory of Open Access Journals (Sweden)
Chocat Rudy
2015-01-01
Full Text Available The design of complex systems often induces a constrained optimization problem under uncertainty. An adaptation of CMA-ES(λ, μ optimization algorithm is proposed in order to efficiently handle the constraints in the presence of noise. The update mechanisms of the parametrized distribution used to generate the candidate solutions are modified. The constraint handling method allows to reduce the semi-principal axes of the probable research ellipsoid in the directions violating the constraints. The proposed approach is compared to existing approaches on three analytic optimization problems to highlight the efficiency and the robustness of the algorithm. The proposed method is used to design a two stage solid propulsion launch vehicle.
Institute of Scientific and Technical Information of China (English)
谭思思; 黄银章; 姚强; 向鹏华; 张小良; 郭维; 龙世平
2015-01-01
easily find that,the seedling effects and agronomic traits of T3 was similar to CK based on comprehensive comparison for physical and chemical properties and seedling growth,and which can substitute commercial peat matrix for seedling in flue-cured tobacco production.
Decellularized and Engineered Tendons as Biological Substitutes: A Critical Review
Directory of Open Access Journals (Sweden)
Arianna B. Lovati
2016-01-01
Full Text Available Tendon ruptures are a great burden in clinics. Finding a proper graft material as a substitute for tendon repair is one of the main challenges in orthopaedics, for which the requirement of a biological scaffold would be different for each clinical application. Among biological scaffolds, the use of decellularized tendon-derived matrix increasingly represents an interesting approach to treat tendon ruptures. We analyzed in vitro and in vivo studies focused on the development of efficient protocols for the decellularization and for the cell reseeding of the tendon matrix to obtain medical devices for tendon substitution. Our review considered also the proper tendon source and preclinical animal models with the aim of entering into clinical trials. The results highlight a wide panorama in terms of allogenic or xenogeneic tendon sources, specimen dimensions, physical or chemical decellularization techniques, and the cell type variety for reseeding from terminally differentiated to undifferentiated mesenchymal stem cells and their static or dynamic culture employed to generate implantable constructs tested in different animal models. We try to identify the most efficient approach to achieve an optimal biological scaffold for biomechanics and intrinsic properties, resembling the native tendon and being applicable in clinics in the near future, with particular attention to the Achilles tendon substitution.
Decellularized and Engineered Tendons as Biological Substitutes: A Critical Review
Lovati, Arianna B.; Bottagisio, Marta; Moretti, Matteo
2016-01-01
Tendon ruptures are a great burden in clinics. Finding a proper graft material as a substitute for tendon repair is one of the main challenges in orthopaedics, for which the requirement of a biological scaffold would be different for each clinical application. Among biological scaffolds, the use of decellularized tendon-derived matrix increasingly represents an interesting approach to treat tendon ruptures. We analyzed in vitro and in vivo studies focused on the development of efficient protocols for the decellularization and for the cell reseeding of the tendon matrix to obtain medical devices for tendon substitution. Our review considered also the proper tendon source and preclinical animal models with the aim of entering into clinical trials. The results highlight a wide panorama in terms of allogenic or xenogeneic tendon sources, specimen dimensions, physical or chemical decellularization techniques, and the cell type variety for reseeding from terminally differentiated to undifferentiated mesenchymal stem cells and their static or dynamic culture employed to generate implantable constructs tested in different animal models. We try to identify the most efficient approach to achieve an optimal biological scaffold for biomechanics and intrinsic properties, resembling the native tendon and being applicable in clinics in the near future, with particular attention to the Achilles tendon substitution. PMID:26880985
Directory of Open Access Journals (Sweden)
Ioan Tomuta
2012-01-01
Full Text Available The aim of this experimental work was to investigate the possibility of obtaining hydroxypropyl methylcellulose (HPMC hydrophilic matrix extended-release dosage forms with metoprolol by using aqueous dispersions of Eudragit NE, as binders in fluid bed granulation. To evaluate the influence of formulation variables (levels of HPMC-Methocel K100 M and Surelease E7 19010 on drug release during a period of time of 12 hours, and on the kinetic release, a full factorial experimental design with two factors and three levels was used. The formulation factors were the granulation polymer concentration and the matrix-forming polymer concentration. The obtained results have shown that the percentage of the drug released during the 12 hours is influenced both by the Methocel ratio and the Eudragit NE ratio; increasing the ratios of Eudragit and Methocel leads to the decrease of the percentage of the released drug. The influence of Eudragit NE percentage is maximum at four and six hours, but the influence of Methocel K100 M concentration is almost the same at all sampling times; all studied formulations showed a kinetic release that fitted best with the Peppas model.
Institute of Scientific and Technical Information of China (English)
綦宏志; 孙长城; 安兴伟; 许敏鹏; 马岚; 明东; 万柏坤
2011-01-01
传统Farwell虚拟字符矩阵BCI中仅采用少数中线导联上的EEG特征进行识别,由于识别信息量较为有限,导致识别效率不高.为此,引入了一种支持向量机特征优化方法,采用扰动支持向量机代价函数的方法评价特征对于分类的贡献,进而优选出适于识别的特征组合.对6位受试者每人各采集80个字符的Farwell虚拟矩阵刺激任务脑电数据,经支持向量特征优化方法进行识别,获得良好的识别效果(识别错误率0.9％).研究表明,支持向量机特征优化方法具有较好的特征选择效果,适用于高特征维度的脑机交互诱发脑电信号降维处理.%Traditional classification in Farwell imaginary character matrix BC1 only uses EEG features on several electrodes located on the middle line. For the limited recognition information, the classification efficiency is low. In this paper, a support vector machine feature optimization method is introduced, which evaluates the feature's contribution to recognition by disturbing cost function of support vector machine and then optimizes the feature combination. EEG signals from 6 subjects evoked by Farwell imaginary matrix task, which includes 80 characters, are collected. Support vector machine feature optimization method is used on these EEG data and classifiers were constructed to recognize the character. The results show that optimal feature combination can improve task recognition accuracy significantly (the recongnition error rate is 0.9%). This study suggests that the support vector machine feature optimization method can provide effective feature selection, so it can be applied to the reduction of feature dimension in high-dimensional evoked EEG signal processing of BC1 and is worthy of further development.
Naydenova, Vessela; Badova, Mariyana; Vassilev, Stoyan; Iliev, Vasil; Kaneva, Maria; Kostov, Georgi
2014-03-04
Two mathematical models were developed for studying the effect of main fermentation temperature (TMF), immobilized cell mass (MIC) and original wort extract (OE) on beer fermentation with alginate-chitosan microcapsules with a liquid core. During the experiments, the investigated parameters were varied in order to find the optimal conditions for beer fermentation with immobilized cells. The basic beer characteristics, i.e. extract, ethanol, biomass concentration, pH and colour, as well as the concentration of aldehydes and vicinal diketones, were measured. The results suggested that the process parameters represented a powerful tool in controlling the fermentation time. Subsequently, the optimized process parameters were used to produce beer in laboratory batch fermentation. The system productivity was also investigated and the data were used for the development of another mathematical model.
Tahaei, Ali; Horley, Paul; Merlin, Mattia; Torres-Torres, David; Garagnani, Gian Luca; Praga, Rolando; Vázquez, Felipe J. García; Arizmendi-Morquecho, Ana
2017-03-01
This work is dedicated to optimization of carbide particle system in a weld bead deposited by PTAW technique over D2 tool steel with high chromium content. The paper reports partial melting of the original carbide grains of the Ni-based filling powder, and growing of the secondary carbide phase (Cr, Ni)_3W_3C in the form of dendrites with wide branches that enhanced mechanical properties of the weld. The optimization of bead parameters was made with design of experiment methodology complemented by a complex sample characterization including SEM, EDXS, XRD, and nanoindentation measurements. It was shown that the preheat of the substrate to a moderate temperature 523 K (250° C) establishes linear pattern of metal flow in the weld pool, resulting in the most homogeneous distribution of the primary carbides in the microstructure of weld bead.
Tahaei, Ali; Horley, Paul; Merlin, Mattia; Torres-Torres, David; Garagnani, Gian Luca; Praga, Rolando; Vázquez, Felipe J. García; Arizmendi-Morquecho, Ana
2017-01-01
This work is dedicated to optimization of carbide particle system in a weld bead deposited by PTAW technique over D2 tool steel with high chromium content. The paper reports partial melting of the original carbide grains of the Ni-based filling powder, and growing of the secondary carbide phase (Cr, Ni)_3 W_3 C in the form of dendrites with wide branches that enhanced mechanical properties of the weld. The optimization of bead parameters was made with design of experiment methodology complemented by a complex sample characterization including SEM, EDXS, XRD, and nanoindentation measurements. It was shown that the preheat of the substrate to a moderate temperature 523 K (250° C) establishes linear pattern of metal flow in the weld pool, resulting in the most homogeneous distribution of the primary carbides in the microstructure of weld bead.
Naydenova, Vessela; Badova, Mariyana; Vassilev, Stoyan; Iliev, Vasil; Kaneva, Maria; Kostov, Georgi
2014-01-01
Two mathematical models were developed for studying the effect of main fermentation temperature (T MF), immobilized cell mass (M IC) and original wort extract (OE) on beer fermentation with alginate-chitosan microcapsules with a liquid core. During the experiments, the investigated parameters were varied in order to find the optimal conditions for beer fermentation with immobilized cells. The basic beer characteristics, i.e. extract, ethanol, biomass concentration, pH and colour, as well as the concentration of aldehydes and vicinal diketones, were measured. The results suggested that the process parameters represented a powerful tool in controlling the fermentation time. Subsequently, the optimized process parameters were used to produce beer in laboratory batch fermentation. The system productivity was also investigated and the data were used for the development of another mathematical model. PMID:26019512
Directory of Open Access Journals (Sweden)
Nieves Carro
2017-03-01
Full Text Available This paper reports the development and optimization of micro-matrix solid-phase dispersion (micro-MSPD of nine polychlorinated biphenyls (PCBs in mussel samples (Mytilus galloprovincialis by using a two-level factorial design. Four variables (amount of sample, anhydrous sodium sulphate, Florisil and solvent volume were considered as factors in the optimization process. The results suggested that only the interaction between the amount of anhydrous sodium sulphate and the solvent volume was statistically significant for the overall recovery of a trichlorinated compound, CB 28. Generally most of the considered species exhibited a similar behaviour, the sample and Florisil amounts had a positive effect on PCBs extractions and solvent volume and sulphate amount had a negative effect. The analytical determination and confirmation of PCBs were carried out by using GC-ECD and GC-MS/MS, respectively. The method was validated having satisfactory precision and accuracy with RSD values below 6% and recoveries between 81 and 116% for all congeners. The optimized method was applied to the extraction of real mussel samples from two Galician Rías.
Carver, Charles S.; Scheier, Michael F.; Segerstrom, Suzanne C.
2010-01-01
Optimism is an individual difference variable that reflects the extent to which people hold generalized favorable expectancies for their future. Higher levels of optimism have been related prospectively to better subjective well-being in times of adversity or difficulty (i.e., controlling for previous well-being). Consistent with such findings, optimism has been linked to higher levels of engagement coping and lower levels of avoidance, or disengagement, coping. There is evidence that optimism is associated with taking proactive steps to protect one's health, whereas pessimism is associated with health-damaging behaviors. Consistent with such findings, optimism is also related to indicators of better physical health. The energetic, task-focused approach that optimists take to goals also relates to benefits in the socioeconomic world. Some evidence suggests that optimism relates to more persistence in educational efforts and to higher later income. Optimists also appear to fare better than pessimists in relationships. Although there are instances in which optimism fails to convey an advantage, and instances in which it may convey a disadvantage, those instances are relatively rare. In sum, the behavioral patterns of optimists appear to provide models of living for others to learn from. PMID:20170998
Pearce, Charles
2009-01-01
Focuses on mathematical structure, and on real-world applications. This book includes developments in several optimization-related topics such as decision theory, linear programming, turnpike theory, duality theory, convex analysis, and queuing theory.
Energy Technology Data Exchange (ETDEWEB)
Colle, C.; Van den Berge, D.; De Wagter, C.; Fortan, L.; Van Duyse, B.; De Neve, W.
1995-12-01
The design of 3D-conformal dose distributions for targets with concave outlines is a technical challenge in conformal radiotherapy. For these targets, it is impossible to find beam incidences for which the target volume can be isolated from the tissues at risk. Commonly occurring examples are most thyroid cancers and the targets located at the lower neck and upper mediastinal levels related to some head and neck. A solution to this problem was developed, using beam intensity modulation executed with a multileaf collimator by applying a static beam-segmentation technique. The method includes the definition of beam incidences and beam segments of specific shape as well as the calculation of segment weights. Tests on Sherouse`s GRATISTM planning system allowed to escalate the dose to these targets to 65-70 Gy without exceeding spinal cord tolerance. Further optimization by constrained matrix inversion was investigated to explore the possibility of further dose escalation.
Boisson, F.; Bekaert, V.; Brasse, D.
2016-03-01
Nowadays, Single Photon imaging has become an essential part of molecular imaging and nuclear medicine. Whether to establish a diagnosis or in the therapeutic monitoring, this modality presents performance that continues to improve. For over 50 years, several collimators have been proposed. Mainly governed by collimation parameters, the resolution-sensitivity trade-off is the factor determining the collimator the most suitable for an intended study. One alternative to the common approaches is the rotating slat collimator (RSC). In the present study, we are aiming at developing a preclinical system equipped with a RSC dedicated to mice and rats imaging, which requires both high sensitivity and spatial resolution. We investigated the resolution-sensitivity trade-offs obtained by varying different collimation parameters: (i) the slats height (H), and (ii) the gap between two consecutive slats (g), considering different intrinsic spatial resolutions. One system matrix was generated for each set of collimation parameters (H,g). Spatial resolutions, Signal-to-Noise Ratio (SNR) and sensitivity obtained for all the set of collimation parameters (H,g) were measured in the 2D projections reconstructed with ML-EM. According to our results, 20 mm high slats and a 1 mm gap were chosen as a good RSC candidate for a preclinical detection module. This collimator will ensure a sensitivity greater than 0.2% and a system spatial resolution below 1 mm, considering an intrinsic spatial resolution below 0.8 mm.
Reino, Danilo Maeda; Maia, Luciana Prado; Fernandes, Patrícia Garani; Souza, Sergio Luis Scombatti de; Taba Junior, Mario; Palioto, Daniela Bazan; Grisi, Marcio Fermandes de Moraes; Jr, Arthur Belém Novaes
2015-10-01
The aim of this randomized controlled clinical study was to compare the extended flap technique (EFT) with the coronally advanced flap technique (CAF) using a porcine collagen matrix (PCM) for root coverage. Twenty patients with two bilateral gingival recessions, Miller class I or II on non-molar teeth were treated with CAF+PCM (control group) or EFT+PCM (test group). Clinical measurements of probing pocket depth (PPD), clinical attachment level (CAL), recession height (RH), keratinized tissue height (KTH), keratinized mucosa thickness (KMT) were determined at baseline, 3 and 6 months post-surgery. At 6 months, the mean root coverage for test group was 81.89%, and for control group it was 62.80% (p<0.01). The change of recession depth from baseline was statistically significant between test and control groups, with an mean of 2.21 mm gained at the control sites and 2.84 mm gained at the test sites (p=0.02). There were no statistically significant differences for KTH, PPD or CAL comparing the two therapies. The extended flap technique presented better root coverage than the coronally advanced flap technique when PCM was used.
Energy Technology Data Exchange (ETDEWEB)
Lebbal, M.R., E-mail: Lebbalmohamedredha@yahoo.fr; Boumaza, T.; Bouchemat, M.
2015-01-01
The elimination of birefringence remains a key challenge in integrated optical systems. In this work, we present birefringence study based on the controlling of layer thickness of planar waveguides, using deposited layers based on magnetic nanoparticles. The birefringence can be reduced with a planar device, depending on a glass substrate. The simulation carried out by MATLAB allowed us to deduce the conditions to decrease the phase mismatch and increase the conversion ratio of modes. - Highlights: • We simulate the birefringence in isotropic and anisotropic waveguides. • The perpendicularly applied gelation field is very promising in decreasing the birefringence. • It is very promising to use the glass substrate and adjust the thin layer thickness. • The glass substrate contributes in increasing the range of mono-mode waveguide. • The optimal thickness is taken close to the cut-off thickness of the 2nd mode TE.
Magnesium substitution in brushite cements.
Alkhraisat, Mohammad Hamdan; Cabrejos-Azama, Jatsue; Rodríguez, Carmen Rueda; Jerez, Luis Blanco; Cabarcos, Enrique López
2013-01-01
The use of magnesium-doped ceramics has been described to modify brushite cements and improve their biological behavior. However, few studies have analyzed the efficiency of this approach to induce magnesium substitution in brushite crystals. Mg-doped ceramics composed of Mg-substituted β-TCP, stanfieldite and/or farringtonite were reacted with primary monocalcium phosphate (MCP) in the presence of water. The cement setting reaction has resulted in the formation of brushite and newberyite within the cement matrix. Interestingly, the combination of SAED and EDX analyses of single crystal has indicated the occurrence of magnesium substitution within brushite crystals. Moreover, the effect of magnesium ions on the structure, and mechanical and setting properties of the new cements was characterized as well as the release of Ca(2+) and Mg(2+) ions. Further research would enhance the efficiency of the system to incorporate larger amounts of magnesium ions within brushite crystals.
Directory of Open Access Journals (Sweden)
Rajesh Kumar Bhuyan
2016-06-01
Full Text Available The objective of this paper is to optimize the process parameters by combined approach of VIKOR and Entropy weight measurement method during Electrical discharge machining (EDM process of Al-18wt.%SiCp metal matrix composite (MMC. The central composite design (CCD method is considered to evaluate the effect of three process parameters; namely pulse on time (Ton, peak current (Ip and flushing pressure (Fp on the responses like material removal rate (MRR, tool wear rate (TWR, Radial over cut (ROC and surface roughness (Ra. The Entropy weight measurement method evaluates the individual weights of each response and, using VIKOR method, the multi-objective responses are optimized to get a single numerical index known as VIKOR Index. Then the Analysis of Variance (ANOVA technique is used to determine the significance of the process parameters on the VIKOR Index. Finally, the result of the VIKOR Indexed is validated by conformation test using the liner mathematical model equation develop by responses surface methodology to identify the effectiveness of the proposed method.
Tsai, Dung-Ying; Chen, Chien-Liang; Ding, Wang-Hsien
2014-07-01
A simple and effective method for the rapid determination of five salicylate and benzophenone-type UV absorbing substances in marketed fish is described. The method involves the use of matrix solid-phase dispersion (MSPD) prior to their determination by on-line silylation gas chromatography tandem mass spectrometry (GC-MS/MS). The parameters that affect the extraction efficiency were optimized using a Box-Behnken design method. The optimal extraction conditions involved dispersing 0.5g of freeze-dried powdered fish with 1.0g of Florisil using a mortar and pestle. This blend was then transferred to a solid-phase extraction (SPE) cartridge containing 1.0g of octadecyl bonded silica (C18), as the clean-up co-sorbent. The target analytes were then eluted with 7mL of acetonitrile. The extract was derivatized on-line in the GC injection-port by reaction with a trimethylsilylating (TMS) reagent. The TMS-derivatives were then identified and quantitated by GC-MS/MS. The limits of quantitation (LOQs) were less than 0.1ng/g. Copyright © 2014 Elsevier Ltd. All rights reserved.
Estimation Method of Homography Matrix Based on Statistical Optimization%基于统计优化的单应矩阵估计算法
Institute of Scientific and Technical Information of China (English)
杨利峰; 谢世朋
2012-01-01
计算机科学中研究的图像是真实世界(即二维、三维欧式空间)到像平面的射影变换.平面射影变换(单应)估计是特征目标检测、注册、识别、三维重建等方面的关键步骤,但是如何鲁棒、精确地估计单应矩阵是一个没有很好解决的问题.在研究中发现,基于点与直线的直接的单应矩阵估计方法会导致出现较大误差的情况.针对这一情况,文中介绍了一种基于统计优化的单应矩阵估计方法,这种方法是通过单应矩阵的协方差张量的计算和优化来估计单应矩阵的.最后进行了简单的实验,比较了统计优化方法与进行归一化处理后的直接线性方法的估计结果,证明了基于优化统计的估计方法更加有效.%The study of the images in computational science is projective transformation between the real world (the two-dimentional and three-dimentional Euclidean geometry) and the plane. Plane projective transformation (homography) estimation is a necessary step in many feature-based object detection, registration, recognition, three-dimention reconstruction and some other aspects, however, ho w to robustly and accurately estimate homography from images is a difficult problem. In this paper found that usual method of homography estimation based on points and lines may result in relatively big errors. Under such configurations, a new estimation method which is based on statistical optimization is proposed in this paper, this method estimates homography matrix through covariance tensor of homography matrix. Have conduced some experiments and compared the estimation results between the method of statistical optimization and the method of normalized DLT,thus proved that the estimation method based on statistical optimization is more effective.
Slavov, Svetoslav H; Geesaman, Elizabeth L; Pearce, Bruce A; Schnackenberg, Laura K; Buzatu, Dan A; Wilkes, Jon G; Beger, Richard D
2012-07-23
An improved three-dimensional quantitative spectral data-activity relationship (3D-QSDAR) methodology was used to build and validate models relating the activity of 130 estrogen receptor binders to specific structural features. In 3D-QSDAR, each compound is represented by a unique fingerprint constructed from (13)C chemical shift pairs and associated interatomic distances. Grids of different granularity can be used to partition the abstract fingerprint space into congruent "bins" for which the optimal size was previously unexplored. For this purpose, the endocrine disruptor knowledge base data were used to generate 50 3D-QSDAR models with bins ranging in size from 2 ppm × 2 ppm × 0.5 Å to 20 ppm × 20 ppm × 2.5 Å, each of which was validated using 100 training/test set partitions. Best average predictivity in terms of R(2)test was achieved at 10 ppm ×10 ppm × Z Å (Z = 0.5, ..., 2.5 Å). It was hypothesized that this optimum depends on the chemical shifts' estimation error (±4.13 ppm) and the precision of the calculated interatomic distances. The highest ranked bins from partial least-squares weights were found to be associated with structural features known to be essential for binding to the estrogen receptor.
Baek, In-Suck; Cho, Byoung-Kwan; Kim, Moon S.; Kim, Young-Sik
2013-05-01
Fluorescence imaging technique has been widely used for quality and safety measurements of agro-food materials. Fluorescence emission intensities of target materials are influenced by wavelengths of excitation sources. Hence, selection of a proper excitation wavelength is an important factor in differentiating target materials effectively. In this study, optimal fluorescence excitation wavelength was determined on the basis of fluorescence emission intensity of defect and sound areas of cherry tomatoes. The result showed that fluorescence responses of defect and sound surfaces of cherry tomatoes were most significantly separated with the excitation light wavelength range between 400 and 410 nm. Fluorescence images of defect cherry tomatoes were acquired with the LEDs with the central wavelength of 410 nm as the excitation source to verify the detection efficiency of cherry tomato defects. The resultant fluorescence images showed that the defects were discriminated from sound areas on cherry tomatoes with above 98% accuracy. This study shows that high power LEDs as the excitation source for fluorescence imaging are suitable for defect detection of cherry tomatoes.
Biologic and synthetic skin substitutes: An overview
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Halim Ahmad
2010-10-01
Full Text Available The current trend of burn wound care has shifted to more holistic approach of improvement in the long-term form and function of the healed burn wounds and quality of life. This has demanded the emergence of various skin substitutes in the management of acute burn injury as well as post burn reconstructions. Skin substitutes have important roles in the treatment of deep dermal and full thickness wounds of various aetiologies. At present, there is no ideal substitute in the market. Skin substitutes can be divided into two main classes, namely, biological and synthetic substitutes. The biological skin substitutes have a more intact extracellular matrix structure, while the synthetic skin substitutes can be synthesised on demand and can be modulated for specific purposes. Each class has its advantages and disadvantages. The biological skin substitutes may allow the construction of a more natural new dermis and allow excellent re-epithelialisation characteristics due to the presence of a basement membrane. Synthetic skin substitutes demonstrate the advantages of increase control over scaffold composition. The ultimate goal is to achieve an ideal skin substitute that provides an effective and scar-free wound healing.
Barry, Jeremy A; Muddiman, David C
2011-12-15
Design of experiments (DOE) is a systematic and cost-effective approach to system optimization by which the effects of multiple parameters and parameter interactions on a given response can be measured in few experiments. Herein, we describe the use of statistical DOE to improve a few of the analytical figures of merit of the infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) source for mass spectrometry. In a typical experiment, bovine cytochrome c was ionized via electrospray, and equine cytochrome c was desorbed and ionized by IR-MALDESI such that the ratio of equine:bovine was used as a measure of the ionization efficiency of IR-MALDESI. This response was used to rank the importance of seven source parameters including flow rate, laser fluence, laser repetition rate, ESI emitter to mass spectrometer inlet distance, sample stage height, sample plate voltage, and the sample to mass spectrometer inlet distance. A screening fractional factorial DOE was conducted to designate which of the seven parameters induced the greatest amount of change in the response. These important parameters (flow rate, stage height, sample to mass spectrometer inlet distance, and laser fluence) were then studied at higher resolution using a full factorial DOE to obtain the globally optimized combination of parameter settings. The optimum combination of settings was then compared with our previously determined settings to quantify the degree of improvement in detection limit. The limit of detection for the optimized conditions was approximately 10 attomoles compared with 100 femtomoles for the previous settings, which corresponds to a four orders of magnitude improvement in the detection limit of equine cytochrome c.
Simple, heart-smart substitutions
Coronary artery disease - heart smart substitutions; Atherosclerosis - heart smart substitutions; Cholesterol - heart smart substitutions; Coronary heart disease - heart smart substitutions; Healthy diet - heart ...
Energy Technology Data Exchange (ETDEWEB)
PI: JUAN C. NINO, ASSOCIATE PROFESSOR
2009-01-11
In order to reduce the current excesses of plutonium (both weapon grade and reactor grade) and other transuranium elements, a concept of inert matrix fuel (IMF) has been proposed for an uranium free transmutation of fissile actinides which excludes continuous uranium-plutonium conversion in thermal reactors and advanced systems. Magnesium oxide (MgO) is a promising candidate for inert matrix (IM) materials due to its high melting point (2827 C), high thermal conductivity (13 W/K {center_dot} m at 1000 C), good neutronic properties, and irradiation stability However, MgO reacts with water and hydrates easily, which prevents it from being used in light water reactors (LWRs) as an IM. To improve the hydration resistance of MgO-based inert matrix materials, Medvedev and coworkers have recently investigated the introduction of a secondary phase that acts as a hydration barrier. An MgO-ZrO{sub 2} composite was specifically studied and the results showed that the composite exhibited improved hydration resistance than pure MgO. However, ZrO{sub 2} is insoluble in most acids except HF, which is undesirable for fuel reprocessing. Moreover, the thermal conductivity of ZrO{sub 2} is low and typically less than 3 W {center_dot} m{sup -1} {center_dot} K{sup -1} at 1000 C. In search for an alternative composite strategy, Nd{sub 2}Zr{sub 2}O{sub 7}, an oxide compound with pyrochlore structure, has been proposed recently as a corrosion resistant phase, and MgO-Nd{sub 2}Zr{sub 2}O{sub 7} composites have been investigated as potential IM materials. An adequate thermal conductivity of 6 W {center_dot} m{sup -} 1 {center_dot} K{sup -1} at 1000 C for the MgO-Nd{sub 2}Zr{sub 2}O{sub 7} composite with 90 vol% MgO was recently calculated and reported. Other simulations proposed that the MgO-pyrochlore composites could exhibit higher radiation stability than previously reported. Final optimization of the composite microstructure was performed on the 70 vol% MgO-Nd{sub 2}Zr{sub 2}O{sub 7
McElvania Tekippe, Erin; Shuey, Sunni; Winkler, David W; Butler, Meghan A; Burnham, Carey-Ann D
2013-05-01
Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) can be used as a method for the rapid identification of microorganisms. This study evaluated the Bruker Biotyper (MALDI-TOF MS) system for the identification of clinically relevant Gram-positive organisms. We tested 239 aerobic Gram-positive organisms isolated from clinical specimens. We evaluated 4 direct-smear methods, including "heavy" (H) and "light" (L) smears, with and without a 1-μl direct formic acid (FA) overlay. The quality measure assigned to a MALDI-TOF MS identification is a numerical value or "score." We found that a heavy smear with a formic acid overlay (H+FA) produced optimal MALDI-TOF MS identification scores and the highest percentage of correctly identified organisms. Using a score of ≥2.0, we identified 183 of the 239 isolates (76.6%) to the genus level, and of the 181 isolates resolved to the species level, 141 isolates (77.9%) were correctly identified. To maximize the number of correct identifications while minimizing misidentifications, the data were analyzed using a score of ≥1.7 for genus- and species-level identification. Using this score, 220 of the 239 isolates (92.1%) were identified to the genus level, and of the 181 isolates resolved to the species level, 167 isolates (92.2%) could be assigned an accurate species identification. We also evaluated a subset of isolates for preanalytic factors that might influence MALDI-TOF MS identification. Frequent subcultures increased the number of unidentified isolates. Incubation temperatures and subcultures of the media did not alter the rate of identification. These data define the ideal bacterial preparation, identification score, and medium conditions for optimal identification of Gram-positive bacteria by use of MALDI-TOF MS.
The impact of single substitutions on multiple sequence alignments.
Klaere, Steffen; Gesell, Tanja; von Haeseler, Arndt
2008-12-27
We introduce another view of sequence evolution. Contrary to other approaches, we model the substitution process in two steps. First we assume (arbitrary) scaled branch lengths on a given phylogenetic tree. Second we allocate a Poisson distributed number of substitutions on the branches. The probability to place a mutation on a branch is proportional to its relative branch length. More importantly, the action of a single mutation on an alignment column is described by a doubly stochastic matrix, the so-called one-step mutation matrix. This matrix leads to analytical formulae for the posterior probability distribution of the number of substitutions for an alignment column.
Wolf, Mike C; Wang, Yao; Freiberg, Alexander N; Aguilar, Hector C; Holbrook, Michael R; Lee, Benhur
2009-07-31
Nipah virus (NiV) and Hendra virus (HeV) are the only paramyxoviruses requiring Biosafety Level 4 (BSL-4) containment. Thus, study of henipavirus entry at less than BSL-4 conditions necessitates the use of cell-cell fusion or pseudotyped reporter virus assays. Yet, these surrogate assays may not fully emulate the biological properties unique to the virus being studied. Thus, we developed a henipaviral entry assay based on a beta-lactamase-Nipah Matrix (betala-M) fusion protein. We first codon-optimized the bacterial betala and the NiV-M genes to ensure efficient expression in mammalian cells. The betala-M construct was able to bud and form virus-like particles (VLPs) that morphologically resembled paramyxoviruses. betala-M efficiently incorporated both NiV and HeV fusion and attachment glycoproteins. Entry of these VLPs was detected by cytosolic delivery of betala-M, resulting in enzymatic and fluorescent conversion of the pre-loaded CCF2-AM substrate. Soluble henipavirus receptors (ephrinB2) or antibodies against the F and/or G proteins blocked VLP entry. Additionally, a Y105W mutation engineered into the catalytic site of betala increased the sensitivity of our betala-M based infection assays by 2-fold. In toto, these methods will provide a more biologically relevant assay for studying henipavirus entry at less than BSL-4 conditions.
Directory of Open Access Journals (Sweden)
Holbrook Michael R
2009-07-01
Full Text Available Abstract Nipah virus (NiV and Hendra virus (HeV are the only paramyxoviruses requiring Biosafety Level 4 (BSL-4 containment. Thus, study of henipavirus entry at less than BSL-4 conditions necessitates the use of cell-cell fusion or pseudotyped reporter virus assays. Yet, these surrogate assays may not fully emulate the biological properties unique to the virus being studied. Thus, we developed a henipaviral entry assay based on a β-lactamase-Nipah Matrix (βla-M fusion protein. We first codon-optimized the bacterial βla and the NiV-M genes to ensure efficient expression in mammalian cells. The βla-M construct was able to bud and form virus-like particles (VLPs that morphologically resembled paramyxoviruses. βla-M efficiently incorporated both NiV and HeV fusion and attachment glycoproteins. Entry of these VLPs was detected by cytosolic delivery of βla-M, resulting in enzymatic and fluorescent conversion of the pre-loaded CCF2-AM substrate. Soluble henipavirus receptors (ephrinB2 or antibodies against the F and/or G proteins blocked VLP entry. Additionally, a Y105W mutation engineered into the catalytic site of βla increased the sensitivity of our βla-M based infection assays by 2-fold. In toto, these methods will provide a more biologically relevant assay for studying henipavirus entry at less than BSL-4 conditions.
Sanches, Livia Rentas; Seulin, Saskia Carolina; Leyton, Vilma; Paranhos, Beatriz Aparecida Passos Bismara; Pasqualucci, Carlos Augusto; Muñoz, Daniel Romero; Osselton, Michael David; Yonamine, Mauricio
2012-04-01
Undoubtedly, whole blood and vitreous humor have been biological samples of great importance in forensic toxicology. The determination of opiates and their metabolites has been essential for better interpretation of toxicological findings. This report describes the application of experimental design and response surface methodology to optimize conditions for enzymatic hydrolysis of morphine-3-glucuronide and morphine-6-glucuronide. The analytes (free morphine, 6-acetylmorphine and codeine) were extracted from the samples using solid-phase extraction on mixed-mode cartridges, followed by derivatization to their trimethylsilyl derivatives. The extracts were analysed by gas chromatography-mass spectrometry with electron ionization and full scan mode. The method was validated for both specimens (whole blood and vitreous humor). A significant matrix effect was found by applying the F-test. Different recovery values were also found (82% on average for whole blood and 100% on average for vitreous humor). The calibration curves were linear for all analytes in the concentration range of 10-1,500 ng/mL. The limits of detection ranged from 2.0 to 5.0 ng/mL. The method was applied to a case in which a victim presented with a previous history of opiate use.
DSP Optimized Implementation of Co-occurrence Matrix Texture Feature%共生矩阵纹理特征的DSP优化实现
Institute of Scientific and Technical Information of China (English)
王职军; 梁光明; 刘任任; 徐克强; 谢俊
2014-01-01
灰度共生矩阵纹理特征具有计算复杂、耗费时间等问题，严重影响了程序执行的效率。针对此问题，分析了共生矩阵纹理特征的原理，研究了TMS320C6678 DSP的结构性能，提出了基于共生矩阵纹理特征的存取带宽和软件流水的优化方法，在CCS5.3软件平台下选择TMS320C6678对其进行了程序实现，最后使程序执行时间从1.94 ms减少到0.259 ms。实验结果表明，提出的优化方法能够缩减代码执行时间，提升代码性能，满足嵌入式图像处理系统的实际需要。%Texture features based on Gray Level Co-occurrence Matrix ( GLCM) has the drawbacks of complex calculations and time-consuming,which seriously affects the efficiency of program execution. Aiming at this problem,analyze the principle of the extracted tex-ture features based on GLCM in this paper,study on the performance of the TMS320C6678 DSP,propose the optimization method of ac-cess bandwidth and software pipelining based on GLCM texture feature,then achieve the optimization of GLCM-based texture features by using of TMS320C6678 in the CCS5. 3 software platform,so that the program execution time is reduced from 1. 94 ms to 0. 259 ms. Ex-periment results show that the proposed optimization method can shrink code execution time, improve code performance and meet the needs of embedded image processing system.
Directory of Open Access Journals (Sweden)
Mariana Carmen Chifiriuc
2012-10-01
Full Text Available The purpose of this study was to design a new nanosystem for catheter surface functionalization with an improved resistance to Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853 colonization and subsequent biofilm development. New 2-((4 ethylphenoxymethyl-N-(substituted-phenylcarbamothioyl-benzamides were synthesized and used for coating a core/shell nanostructure. Their chemical structures were elucidated by NMR, IR and elemental analysis, being in agreement with the proposed ones. Fe3O4/C12 of up to 5 nm size had been synthesized with lauric acid as a coating agent and characterized by XRD, FT-IR, TGA, TEM and biological assays. The catheter pieces were coated with the fabricated nanofluid in magnetic field. The microbial adherence ability was investigated in 6 multiwell plates by using culture based methods and Scanning Electron Microscopy (SEM. The nanoparticles coated with the obtained compounds 1a–c inhibited the adherence and biofilm development ability of the S. aureus and P. aeruginosa tested strains on the catheter functionalized surface, as shown by the reduction of viable cell counts and SEM examination of the biofilm architecture. Using the novel core/shell/adsorption-shell to inhibit the microbial adherence could be of a great interest for the biomedical field, opening new directions for the design of film-coated surfaces with improved anti-biofilm properties.
Evaluation of dermal substitute in a novel co-transplantation model with autologous epidermal sheet.
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Guofeng Huang
Full Text Available The development of more and more new dermal substitutes requires a reliable and effective animal model to evaluate their safety and efficacy. In this study we constructed a novel animal model using co-transplantation of autologous epidermal sheets with dermal substitutes to repair full-thickness skin defects. Autologous epidermal sheets were obtained by digesting the basement membrane (BM and dermal components from rat split-thickness skins in Dispase II solution (1.2 u/ml at 4 °C for 8, 10 and 12 h. H&E, immunohistochemical and live/dead staining showed that the epidermal sheet preserved an intact epidermis without any BM or dermal components, and a high percentage of viable cells (92.10 ± 4.19% and P63 positive cells (67.43 ± 4.21% under an optimized condition. Porcine acellular dermal matrixes were co-transplanted with the autologous epidermal sheets to repair full-thickness skin defects in Sprague-Dawley rats. The epidermal sheets survived and completely re-covered the wounds within 3 weeks. Histological staining showed that the newly formed stratified epidermis attached directly onto the dermal matrix. Inflammatory cell infiltration and vascularization of the dermal matrix were not significantly different from those in the subcutaneous implantation model. Collagen IV and laminin distributed continuously at the epidermis and dermal matrix junction 4 weeks after transplantation. Transmission electron microscopy further confirmed the presence of continuous lamina densa and hemidesmosome structures. This novel animal model can be used not only to observe the biocompatibility of dermal substitutes, but also to evaluate their effects on new epidermis and BM formation. Therefore, it is a simple and reliable model for evaluating the safety and efficacy of dermal substitutes.
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R. L. de Zafra
2011-07-01
Full Text Available The Ground-Based Millimeter-wave Spectrometer (GBMS was designed and built at the State University of New York at Stony Brook in the early 1990s and since then has carried out many measurement campaigns of stratospheric O3, HNO3, CO and N2O at polar and mid-latitudes. Its HNO3 data set shed light on HNO3 annual cycles over the Antarctic continent and contributed to the validation of both generations of the satellite-based JPL Microwave Limb Sounder (MLS. Following the increasing need for long-term data sets of stratospheric constituents, we resolved to establish a long-term GMBS observation site at the Arctic station of Thule (76.5° N, 68.8° W, Greenland, beginning in January 2009, in order to track the long- and short-term interactions between the changing climate and the seasonal processes tied to the ozone depletion phenomenon. Furthermore, we updated the retrieval algorithm adapting the Optimal Estimation (OE method to GBMS spectral data in order to conform to the standard of the Network for the Detection of Atmospheric Composition Change (NDACC microwave group, and to provide our retrievals with a set of averaging kernels that allow more straightforward comparisons with other data sets. The new OE algorithm was applied to GBMS HNO3 data sets from 1993 South Pole observations to date, in order to produce HNO3 version 2 (v2 profiles. A sample of results obtained at Antarctic latitudes in fall and winter and at mid-latitudes is shown here. In most conditions, v2 inversions show a sensitivity (i.e., sum of column elements of the averaging kernel matrix of 100 ± 20 % from 20 to 45 km altitude, with somewhat worse (better sensitivity in the Antarctic winter lower (upper stratosphere. The 1σ uncertainty on HNO3 v2 mixing ratio vertical profiles depends on altitude and is estimated at ~15 % or 0.3 ppbv, whichever is larger. Comparisons of v2 with former (v1 GBMS HNO3 vertical profiles, obtained employing the constrained matrix inversion method
Novel Optimization Method for Projection Matrix in Compress Sensing Theory%一种用于压缩感知理论的投影矩阵优化算法
Institute of Scientific and Technical Information of China (English)
吴光文; 张爱军; 王昌明
2015-01-01
Considering the influence of the projection matrix on Compressed Censing (CS), a novel method is proposed to optimize the projection matrix. In order to improve the signal’s reconstruction precise and the stability of the optimization algorithm of the projection matrix, the proposed method adopts a differentiable threshold function to shrink the off-diagonal items of a Gram matrix corresponding to the mutual coherence between the projection matrix and sparse dictionary, and introduces a gradient descent approach based on the Wolf’s-conditions to solve the optimization projection matrix. The Basis-Pursuit (BP) algorithm and the Orthogonal Matching Pursuit (OMP) algorithm are applied to find the solution of the minimum l0-norm optimization issue and the compressed sensing are utilized to sense and reconstruct the random vectors, wavelet’s noise test signals and pictures. The results of the simulation show the proposed method based on the projection matrix optimization is able to improve the quality of the reconstruction performance.%考虑到投影矩阵对压缩感知(CS)算法性能的影响，该文提出一种优化投影矩阵的算法。该方法提出可导的阈值函数，通过收缩 Gram 矩阵非对角元的方法压缩投影矩阵和稀疏字典的相关系数，引入基于沃尔夫条件(Wolfe’s conditions)的梯度下降法求解最佳投影矩阵，达到提高投影矩阵优化算法稳定度和重构信号精度的目的。通过基追踪(BP)算法和正交匹配追踪(OMP)算法求解l0优化问题，用压缩感知方法实现随机稀疏向量、小波测试信号和图像信号的感知和重构。仿真实验表明，该文提出的投影矩阵优化算法能较大地提高重构信号的精度。
Inventory Decisions in a Product-Updated System with Component Substitution and Product Substitution
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Yancong Zhou
2013-01-01
Full Text Available Substitution behaviors happen frequently when demands are uncertain in a production inventory system, and it has attracted enough attention from firms. Related researches can be clearly classified into firm-driven substitution and customer-driven substitution. However, if production inventory is stock-out when a firm updates its product, the firm may use a new generation product to satisfy the customer’s demand of old generation product or use updated component to substitute old component to satisfy production demand. Obviously, two cases of substitution exist simultaneously in the product-updated system when an emergent shortage happens. In this paper, we consider a component order problem with component substitution and product substitution simultaneously in a product-updated system, where the case of firm-driven substitution or customer-driven substitution can be reached by setting different values for two system parameters. Firstly, we formulate the problem into a two-stage dynamic programming. Secondly, we give the optimal decisions about assembled quantities of different types of products. Next, we prove that the expected profit function is jointly concave in order quantities and decrease the feasible domain by determining some bounds for decision variables. Finally, some management insights about component substitution and product substitution are investigated by theoretical analysis method.
Energy Technology Data Exchange (ETDEWEB)
Ghosh, Subrata Kumar, E-mail: subratagh82@gmail.com [Department of Mechanical Engineering, National Institute of Technology Agartala, Tripura 799055 (India); Bandyopadhyay, Kaushik; Saha, Partha [Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302 (India)
2014-07-01
In the present investigation, an in-situ multi-component reinforced aluminum based metal matrix composite was fabricated by the combination of self-propagating high-temperature synthesis and direct metal laser sintering process. The different mixtures of Al, TiO{sub 2} and B{sub 4}C powders were used to initiate and maintain the self-propagating high-temperature synthesis by laser during the sintering process. It was found from the X-ray diffraction analysis and scanning electron microscopy that the reinforcements like Al{sub 2}O{sub 3}, TiC, and TiB{sub 2} were formed in the composite. The scanning electron microscopy revealed the distribution of the reinforcement phases in the composite and phase identities. The variable parameters such as powder layer thickness, laser power, scanning speed, hatching distance and composition of the powder mixture were optimized for higher density, lower porosity and higher microhardness using Taguchi method. Experimental investigation shows that the density of the specimen mainly depends upon the hatching distance, composition and layer thickness. On the other hand, hatching distance, layer thickness and laser power are the significant parameters which influence the porosity. The composition, laser power and layer thickness are the key influencing parameters for microhardness. - Highlights: • The reinforcements such as Al{sub 2}O{sub 3}, TiC, and TiB{sub 2} were produced in Al-MMC through SHS. • The density is mainly influenced by the material composition and hatching distance. • Hatching distance is the major influencing parameter on porosity. • The material composition is the significant parameter to enhance the microhardness. • The SEM micrographs reveal the distribution of TiC, TiB{sub 2} and Al{sub 2}O{sub 3} in the composite.
Institute of Scientific and Technical Information of China (English)
高祖安
2012-01-01
综述分析了石棉及其石棉行业存在严重危害性等实际情况,对国外开发的各种石棉替代品的试验、试用和实际应用情况进行了对比。结果表明,聚乙烯醇（PVA）纤维具有高强高模、低伸长、耐酸碱、抗溶剂、耐老化、水泥粘着力好、性价比高等优良特点,以及国外近20年的基础研究和工程应用实践证明,被国际公认为替代石棉的最理想材料。最后提出在我国加快PVA纤维代替石棉的迫切性与必要性。%This paper summarizes and analyzes the serious harm to human health caused by asbestos and asbestos industry and other actual situations, then have a comparison through experiment, trial and practical application of various kinds of asbestos substitutes developed abroad. The results indicate that PVA fibers have good performances of high strength and high modulus, low elongation, acid and alkali resistant, anti-solvent, anti-aging, good cement adhesiveness, cost effective and etc. On basis of the nearly 20 years＇ basic research and engineering practice in abroad, PVA is considered to be the optimal substitute for asbestos. Finally the paper leads to a conclusion that it＇s urgent and necessary to accelerate the development of PVA alternative technology of asbestos.
Cui, S. T.; Zhu, S. Y.; Wang, A. F.; Kong, S.; Ju, S. L.; Luo, X. G.; Chen, X. H.; Zhang, G. B.; Sun, Z.
2012-10-01
Using angle-resolved photoemission spectroscopy, we studied the evolution of electronic structure of NaFe1-xCoxAs from an optimally doped superconducting compound (x=0.028) to a heavily overdoped nonsuperconducting one (x=0.109). As in “122”-type iron pnictides, our data suggest that the Co dopant in NaFe1-xCoxAs supplies extra charge carriers and shifts the Fermi level accordingly. The overall band renormalization remains basically the same throughout the doping range we studied, suggesting that the local magnetic and electronic correlations are not affected by carrier doping. In the x=0.109 compound, the holelike bands around the zone center Γ move to deeper binding energies and an electron pocket appears instead, resulting in a Fermi surface topology similar to that of AxFe2-ySe2 (A=K, Cs, Rb, Tl). Our data suggest that a balance between itinerant properties of mobile carriers and local interactions plays an important role for the superconductivity in these materials.
Institute of Scientific and Technical Information of China (English)
李富萍; 张建华
2012-01-01
层次分析法中残缺判断矩阵的修补可以归结为一个在满足一致性比例条件下为残缺要素寻找最合适的值的优化问题。针对这个优化问题，提出利用粒子群算法修补残缺判断矩阵的算法。文中对基于粒子群优化算法的残缺判断矩阵修补基本思路进行了介绍，然后给出了具体的算法描述，最后给出实验数据及其分析。实验结果验证了此算法的有效性。%The patch of incomplete AHP judgment matrix can be attributed to a optimization problem to seek the best value and the consistency index of the judgment matrix is satisfied. An algorithm for incomplete judgment matrix patching by using the Particle Swarm Optimization was presented in this paper. First, the method of incomplete judgment matrix patching was introduced, and then the algorithm was described in detail. Finally, the experimental data and the analysis are given. Experimental results proved the effectiveness of such algorithm.
Institute of Scientific and Technical Information of China (English)
王伟锋; 闫会峰
2013-01-01
为了解决大型、超大型矩阵计算中处理速度较慢的问题，采用代数学、算法学相结合的方法，对缺乏实际分块标准与方法的矩阵分块问题进行探讨。通过引入带回溯机制的冒泡排序法，有效地建立了矩阵最佳分块方法。在此基础上，将最佳分块方法从理论上应用于矩阵乘积运算中，从而为降低复杂矩阵运算复杂度提出了切实可行的明确的改善方法。%In order to solve the problem of large, super large matrix calculation of slower processing speed problem, using algebra, arithmetic method, the lack of actual block standard and method of block matrix problems. By introducing a backtracking mechanism of bubble sort method, effectively established the optimal partition method. On the basis of this, the optimal partitioning method from the theory is applied to the matrix multiplication, so as to reduce the computing complexity of complex matrix and proposes some practical and feasible clear improvement method.
Franklin, Joel N
2003-01-01
Mathematically rigorous introduction covers vector and matrix norms, the condition-number of a matrix, positive and irreducible matrices, much more. Only elementary algebra and calculus required. Includes problem-solving exercises. 1968 edition.
Energy Technology Data Exchange (ETDEWEB)
Fiorucci, I.; Muscari, G. [Istituto Nazionale di Geofisica e Vulcanologia, Rome (Italy); De Zafra, R.L. [State Univ. of New York, Stony Brook, NY (United States). Dept. of Physics and Astronomy
2011-07-01
The Ground-Based Millimeter-wave Spectrometer (GBMS) was designed and built at the State University of New York at Stony Brook in the early 1990s and since then has carried out many measurement campaigns of stratospheric O{sub 3}, HNO{sub 3}, CO and N{sub 2}O at polar and mid-latitudes. Its HNO{sub 3} data set shed light on HNO{sub 3} annual cycles over the Antarctic continent and contributed to the validation of both generations of the satellite-based JPL Microwave Limb Sounder (MLS). Following the increasing need for long-term data sets of stratospheric constituents, we resolved to establish a long-term GMBS observation site at the Arctic station of Thule (76.5 N, 68.8 W), Greenland, beginning in January 2009, in order to track the long- and short-term interactions between the changing climate and the seasonal processes tied to the ozone depletion phenomenon. Furthermore, we updated the retrieval algorithm adapting the Optimal Estimation (OE) method to GBMS spectral data in order to conform to the standard of the Network for the Detection of Atmospheric Composition Change (NDACC) microwave group, and to provide our retrievals with a set of averaging kernels that allow more straightforward comparisons with other data sets. The new OE algorithm was applied to GBMS HNO{sub 3} data sets from 1993 South Pole observations to date, in order to produce HNO{sub 3} version 2 (v2) profiles. A sample of results obtained at Antarctic latitudes in fall and winter and at mid-latitudes is shown here. In most conditions, v2 inversions show a sensitivity (i.e., sum of column elements of the averaging kernel matrix) of 100{+-}20% from 20 to 45 km altitude, with somewhat worse (better) sensitivity in the Antarctic winter lower (upper) stratosphere. The 1{sigma} uncertainty on HNO{sub 3} v2 mixing ratio vertical profiles depends on altitude and is estimated at {proportional_to}15% or 0.3 ppbv, whichever is larger. Comparisons of v2 with former (v1) GBMS HNO{sub 3} vertical profiles
40 CFR 721.8780 - Substituted pyridine azo substituted phenyl.
2010-07-01
... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted pyridine azo substituted... Specific Chemical Substances § 721.8780 Substituted pyridine azo substituted phenyl. (a) Chemical substance... substituted pyridine azo substituted phenyl (PMNs P-96-767 and P-96-773) are subject to reporting under...
Design of Optimal Diffusion Layers for SPN Block Ciphers
Institute of Scientific and Technical Information of China (English)
CUI Ling-guo; CAO Yuan-da
2006-01-01
The diffusion layers in substitution-permutation network(SPN) block ciphers are almost invertible linear transformations, which is optimal if the branch number reaches the maximum value. The method of constructing involutory optimal diffusion layers is proposed based on the Cauchy matrix, which can decrease the cost of implementation. The analysis to experimental results indicates that the diffusion layer ensures the security of the SPN block cipher against differential cryptanalysis(DC) and linear cryptanalysis(LC), and decreases half the cost of implementation.
Ball, David W.; Zehe, Michael J.
1993-01-01
BF3 was co-condensed with H2O, D2O, (C2H5)2O, (CF3CH2)2O, and (C2F5)2O in excess argon at 15 K. Infrared spectra of BF3/water isolated in solid argon provided a more complete analysis of the BF3--H2O complex than previously published. Infrared spectra of the matrices showed a definite Lewis acid-base interaction between BF3 and diethyl ether; a weak but definite interaction with bis (2,2,2-trifluorodiethyl) ether, and no observable interaction with perfluorodiethyl ether. Thus, the ether data indicate a clear trend between strength of interaction with BF3 and the degree of F substitution. To support and explain the emerging relationship between interaction strength and the basicity of the oxygen-containing molecule, the proton affinity of (CF3CH2)2O was measured using chemical ionization mass spectrometry. The implications of the results for lubricant/metal oxide surface interactions are discussed.
Medicineringsfejl ved generisk substitution
DEFF Research Database (Denmark)
Rölfing, Jan
2012-01-01
Generic substitution is a major cause of medical mistakes in the general population. Danish legislation obligates pharmacies to substitute prescribed medicine with the cheapest equivalent formulation, despite variations in product name, packaging, shape and colour. Consequently, medical mistakes ...... occur. Scientific evidence on the consequences of generic substitution is sparse. Call upon fellow health workers to report medical mistakes to the national entities and scientific peers, in order to increase awareness and scientific evidence about the problem....
Cyclotomic Aperiodic Substitution Tilings
Directory of Open Access Journals (Sweden)
Stefan Pautze
2017-01-01
Full Text Available The class of Cyclotomic Aperiodic Substitution Tilings (CASTs is introduced. Its vertices are supported on the 2 n -th cyclotomic field. It covers a wide range of known aperiodic substitution tilings of the plane with finite rotations. Substitution matrices and minimal inflation multipliers of CASTs are discussed as well as practical use cases to identify specimen with individual dihedral symmetry D n or D 2 n , i.e., the tiling contains an infinite number of patches of any size with dihedral symmetry D n or D 2 n only by iteration of substitution rules on a single tile.
Jalbani, Nusrat; Kazi, Tasneem Gul; Jamali, Muhammad Khan; Arain, Muhammad Balal; Afridi, Hassan Imran; Sheerazi, Syed T; Ansari, Rehana
2007-01-01
A simple and rapid method based on ultrasound energy is described for the determination of aluminum (AI) in complex matrixes of chocolate and candy samples by electrothermal atomic absorption spectrometry. The optimization strategy was carried out using multivariate methodologies. Five variables (temperature of the ultrasonic bath; exposure time to ultrasound energy; volumes of 2 acid mixtures, HNO3-H2SO4-H2O2 (1 + 1 + 1) and HNO3-H2O2 (1 + 1); and sample mass) were considered as factors in the optimization process. Interactions between analytical factors and their optimal levels were investigated using fractional factorial and Doehlert matrix designs. Validation of the ultrasonic-assisted acid digestion procedure was performed against standard reference materials, milk powder (SRM 8435) and wheat flour (SRM 1567a). The proposed procedure allowed Al determination with a detection limit of 2.3 microg/L (signal-to-noise = 3) and a precision, calculated as relative standard deviation, of 2.2% for a set of 10 measurements of certified samples. The recovery of Al by the proposed procedure was close to 100%, and no significant difference at the 95% confidence level was found between determined and certified values of Al. The proposed procedure was applied to the determination of Al in chocolate and candy samples. The results indicated that cocoa-based chocolates have higher contents of Al than milk- and sugar-based chocolates and candies.
Matrix Factorization and Matrix Concentration
Mackey, Lester
2012-01-01
Motivated by the constrained factorization problems of sparse principal components analysis (PCA) for gene expression modeling, low-rank matrix completion for recommender systems, and robust matrix factorization for video surveillance, this dissertation explores the modeling, methodology, and theory of matrix factorization.We begin by exposing the theoretical and empirical shortcomings of standard deflation techniques for sparse PCA and developing alternative methodology more suitable for def...
Tiantao, Zhao; Youcai, Zhao; Lijie, Zhang; Haoquan, Chen; Feng, Shi; Haiyan, Zhou
2011-11-01
Acetylene has been found to significantly inhibit biological activity of methanogens and thus might be applicable for reducing the generation and emission of methane from municipal solid waste landfills. However, acetylene is gaseous and so it is considered physically infeasible to directly apply this gas to waste in landfill conditions. In the present study, a novel acetylene release mechanism was tested, using a matrix of acetylene entrapped in high hydrophobic paraffin wax and/or rosin and calcium carbide capsules with a ratio of 1.0 g g(-1) matrix and a diameter of 10 mm to facilitate the gradual release of acetylene. A diffusion mechanism model (Q = &b.gamma; × t (0.5)) for the matrix was derived based on the T. Higuchi equation, and the effective diffusion coefficients (D(e)) were acquired by linear fitting. Additionally, it was found that D(e) remained constant when the rosin content was up to more than 20% g g(-1) matrix.
Directory of Open Access Journals (Sweden)
Federico A. Sturzeneger
1992-03-01
Full Text Available Currency Substitution and the Regressivity of Inflationary Taxation The purpose of this paper is to show that in the presence of financial adaptation or currency substitution. the inflation tax is extremely regressive. This regressivity arises from the existence of a fixed cost of switching to inflation-proof transactions technologies. This fixed cost makes it optimal only for those agents with sufficiently high incomes to switch out of domestic currency. The effects are illustrated and quantified for a particular case.
Bodewig, E
1959-01-01
Matrix Calculus, Second Revised and Enlarged Edition focuses on systematic calculation with the building blocks of a matrix and rows and columns, shunning the use of individual elements. The publication first offers information on vectors, matrices, further applications, measures of the magnitude of a matrix, and forms. The text then examines eigenvalues and exact solutions, including the characteristic equation, eigenrows, extremum properties of the eigenvalues, bounds for the eigenvalues, elementary divisors, and bounds for the determinant. The text ponders on approximate solutions, as well
Institute of Scientific and Technical Information of China (English)
蒋健; 汪隆君
2015-01-01
Aiming at problems such as concentrated compensation points and overlapping compensation range of reactive power matrix method in reactive power compensation optimization of power distribution network,a kind of improved pre-cise matrix method was studied. According to several times of load flow results ,compensation points were selected and com-pensation capacities were confirmed. Meanwhile,deficiencies of original optimization method by using only once load flow result were changed,concept of virtual root node was discussed and reactive power compensation points and capacities were determined based on modified precise matrix concept. Example results indicate that it is not only able to overcome problems of concentrated compensation points and overlapping compensation range,but also reflect strong practicability and effective-ness by using the improved precise matrix method for reactive power optimization in the power distribution network.%针对无功精确矩法在配电网无功补偿优化中存在的补偿点集中、补偿范围重叠等问题，研究了一种改进精确矩法。根据多次的潮流结果选择补偿点并确定其补偿容量，改变了原来仅利用一次潮流计算结果进行优化的不足，并探讨“虚根节点”的概念，利用修正的无功精确矩定义确定无功补偿地点和补偿容量。算例结果表明，采用改进的无功精确矩法进行配电网无功优化，不仅克服了原来补偿点集中、补偿范围重叠的问题，而且具有很强的实用性和有效性。
Intachai, Kannaporn; Singboottra, Panthong; Leksawasdi, Noppol; Kasinrerk, Watchara; Tayapiwatana, Chatchai; Butr-Indr, Bordin
2015-01-01
The optimal culture condition for extracellular recombinant single chain variable fragment anti HIV-1 p17 protein (scFv anti-p17) production in Escherichia coli HB2151 was investigated by the sequential simplex optimization (SS) method. Five variable parameters were submitted in the fermentation process. The most favorable condition obtained from 19 independent experiments was as followed: 58 µM of IPTG induction to 1.7 OD600 nm at 25.5°C for 16 h with 202 rpm agitation rate. The amount of secreted scFv anti-p17 at the optimal condition was 38% higher than under the control condition. The binding activity of soluble extracellular scFv anti-p17 protein increased 95.5% and 73.2% in comparison with the control condition and non-optimized condition respectively. The soluble scFv anti-p17 from crude HB2151 lysated was subsequently purified by immobilized metal ion affinity chromatography (IMAC) with His-tag. The purified scFv anti-p17 was intact and retained its antigen-binding affinity against HIV-1 p17. We demonstrated that the sequential simplex optimization method was a key for exertion of high yield with fewer experimental requirements for acquiring of large scale secretory protein production.
A. Monroy-Villagrana; C. Cano-Sarmiento; L. Alamilla-Beltrán; H. Hernández-Sánchez; G.F. Gutiérrez-López
2014-01-01
The effect of composition (Arabic gum (AG), maltodextrin (MD), surfactants, pH) and processing parameters (pressure and number of cycles of microfluidization) of α-tocopherol (AT) emulsions was studied via a coupled Taguchi-RMS optimization. Creaming index (CI), particle size (PS) and zeta potential ( α) were selected as response variables. The estimated optimal conditions were found at GA of 40%, MD/surfactant mixture of 60%, 30% AT, pH of 4.9, P of 76 MPa and five cycles of microfluidizatio...
A Method to Solve the Optimal Mixed Strategy of Matrix Game%矩阵对策最优混合策略的求解方法
Institute of Scientific and Technical Information of China (English)
陈晓敏
2001-01-01
有多种方法可以求解矩阵对策的最优混合策略，但计算量都很大.利用微软的Excel提供的“规划求解”方法用计算机求解矩阵对策的最优混合策略，可以减少计算量.%There are several methods to solve the problem of the opitimal mixed strategy of matrix game. But the amount of calculating is heavy. However, using the programming solution tod of MS Excel to solve the problem can reduce the amov calculating amount.
2009-01-01
Abstract Nipah virus (NiV) and Hendra virus (HeV) are the only paramyxoviruses requiring Biosafety Level 4 (BSL-4) containment. Thus, study of henipavirus entry at less than BSL-4 conditions necessitates the use of cell-cell fusion or pseudotyped reporter virus assays. Yet, these surrogate assays may not fully emulate the biological properties unique to the virus being studied. Thus, we developed a henipaviral entry assay based on a β-lactamase-Nipah Matrix (βla-M) fusion protein...
Nakamura, Akihiro; Komatsu, Masaru; Kondo, Akira; Ohno, Yuki; Kohno, Hisashi; Nakamura, Fumihiko; Matsuo, Shuji; Ohnuma, Kenichiro; Hatano, Naoya; Kawano, Seiji
2015-11-01
One reason for the spread of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli worldwide is the global pandemic of the B2-ST131 clonal group. We searched for the specific biomarker peaks to distinguish between the B2-ST131 clonal group and other sequence type (ST) clonal groups isolated from clinical specimens obtained in our hospital. Biomarker peaks at m/z 7650 in the B2-ST131 group (sensitivity of 100% and specificity of 89.7%) and m/z 7707 in the other ST clonal groups showed the highest discrimination abilities. We further verified reproducibility against other Japanese clinical isolates obtained in another area of Japan. Differences between the molecular mass at the 7650m/z and 7707m/z peaks indicated an E34A amino acid substitution by proteomic and genomic analysis. Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry rapidly and simply identified the B2-ST131 clonal group in routine examinations and will allow for adequate empirical therapy and the possibility to control both hospital infections and the global pandemic.
Synthesis of substituted pyrazines
Energy Technology Data Exchange (ETDEWEB)
Pagoria, Philip F.; Zhang, Mao Xi
2016-10-04
A method for synthesizing a pyrazine-containing material according to one embodiment includes contacting an iminodiacetonitrile derivative with a base and a reagent selected from a group consisting of hydroxylamine, a hydroxylamine salt, an aliphatic primary amine, a secondary amine, an aryl-substituted alkylamine a heteroaryl-substituted alkyl amine, an alcohol, an alkanolamine and an aryl alcoholamine. Additional methods and several reaction products are presented. ##STR00001##
Baldo, M; Sapershtejn, E E; Zverev, M V
2002-01-01
Validity of the local-potential approximation (LPA) elaborated previously for the problem of the singlet pairing in semi-infinite nuclear matter is analyzed in the case of Bethe-Goldstone equation for the Brueckner G matrix. The method of solving this equation for a slab of nuclear matter developed recently is used with the separable form of the NN interaction. The singlet sup 1 S sub 0 and the triplet sup 3 S sub 1 + sup 3 D sub 1 channels are considered. The complete two-particle Hilbert space is split into two domains, the model subspace and the complementary one, separated by the energy E sub 0. In the first subspace, the two-particle propagator is calculated explicitly, whereas the LPA is used in the second one. Keeping in mind the subsequent use of the G matrix for evaluating the Landau-Migdal interaction amplitude, the total energy is taken as E = 2 mu, mu being the chemical potential of the system under consideration. Numerical calculations are made for mu = -8 MeV. Validity of the LPA is investigated...
Directory of Open Access Journals (Sweden)
J.S. Pang
2014-08-01
Full Text Available This paper introduces the application of Taguchi optimization methodology in optimizing the cutting parameters of end-milling process for machining the halloysite nanotubes (HNTs with aluminium reinforced epoxy hybrid composite material under dry condition. The machining parameters which are chosen to be evaluated in this study are the depth of cut (d, cutting speed (S and feed rate (f. While, the response factors to be measured are the surface roughness of the machined composite surface and the cutting force. An orthogonal array of the Taguchi method was set-up and used to analyse the effect of the milling parameters on the surface roughness and cutting force. The result from this study shows that the application of the Taguchi method can determine the best combination of machining parameters that can provide the optimal machining response conditions which are the lowest surface roughness and lowest cutting force value. For the best surface finish, A1–B3–C3 (d = 0.4 mm, S = 1500 rpm, f = 60 mmpm is found to be the optimized combination of levels for all the three control factors from the analysis. Meanwhile, the optimized combination of levels for all the three control factors from the analysis which provides the lowest cutting force was found to be A2–B2–C2 (d = 0.6 mm, S = 1000 rpm, f = 40 mmpm.
DiMaggio, Peter A; Subramani, Ashwin; Judson, Richard S; Floudas, Christodoulos A
2010-11-01
In this work, we combine the strengths of mixed-integer linear optimization (MILP) and logistic regression for predicting the in vivo toxicity of chemicals using only their measured in vitro assay data. The proposed approach utilizes a biclustering method based on iterative optimal reordering (DiMaggio, P. A., McAllister, S. R., Floudas, C. A., Feng, X. J., Rabinowitz, J. D., and Rabitz, H. A. (2008). Biclustering via optimal re-ordering of data matrices in systems biology: rigorous methods and comparative studies. BMC Bioinformatics 9, 458-474.; DiMaggio, P. A., McAllister, S. R., Floudas, C. A., Feng, X. J., Rabinowitz, J. D., and Rabitz, H. A. (2010b). A network flow model for biclustering via optimal re-ordering of data matrices. J. Global. Optim. 47, 343-354.) to identify biclusters corresponding to subsets of chemicals that have similar responses over distinct subsets of the in vitro assays. The biclustering of the in vitro assays is shown to result in significant clustering based on assay target (e.g., cytochrome P450 [CYP] and nuclear receptors) and type (e.g., downregulated BioMAP and biochemical high-throughput screening protein kinase activity assays). An optimal method based on mixed-integer linear optimization for reordering sparse data matrices (DiMaggio, P. A., McAllister, S. R., Floudas, C. A., Feng, X. J., Li, G. Y., Rabinowitz, J. D., and Rabitz, H. A. (2010a). Enhancing molecular discovery using descriptor-free rearrangement clustering techniques for sparse data sets. AIChE J. 56, 405-418.; McAllister, S. R., DiMaggio, P. A., and Floudas, C. A. (2009). Mathematical modeling and efficient optimization methods for the distance-dependent rearrangement clustering problem. J. Global. Optim. 45, 111-129) is then applied to the in vivo data set (21.7% sparse) in order to cluster end points that have similar lowest effect level (LEL) values, where it is observed that the end points are effectively clustered according to (1) animal species (i.e., the
Craps, Ben; Nguyen, Kévin
2016-01-01
Matrix quantum mechanics offers an attractive environment for discussing gravitational holography, in which both sides of the holographic duality are well-defined. Similarly to higher-dimensional implementations of holography, collapsing shell solutions in the gravitational bulk correspond in this setting to thermalization processes in the dual quantum mechanical theory. We construct an explicit, fully nonlinear supergravity solution describing a generic collapsing dilaton shell, specify the holographic renormalization prescriptions necessary for computing the relevant boundary observables, and apply them to evaluating thermalizing two-point correlation functions in the dual matrix theory.
Directory of Open Access Journals (Sweden)
Yaping Hu
2015-01-01
the nonsmooth convex optimization problem. First, by using Moreau-Yosida regularization, we convert the original objective function to a continuously differentiable function; then we use approximate function and gradient values of the Moreau-Yosida regularization to substitute the corresponding exact values in the algorithm. The global convergence is proved under suitable assumptions. Numerical experiments are presented to show the effectiveness of this algorithm.
Prioritizing substitution of organic solvents in industrial cleaning processes
DEFF Research Database (Denmark)
Rasmussen, Pia Brunn; Jacobsen, Thomas
1997-01-01
A method for prioritizing the substitution of volatile organic compounds (VOC) used in industrial cleaning processes is developed. The result is a matrix, which, if all information can be obtained, gives a comprehensive description of the effects, exposure and emission of VOC, as well...... as the prospects for performing the substitution with a vegetable ester. It can be a tool for companies to decide which cleaning process has the highest demand for substitution, if there is a choice between several processes, but it may also be a tool to convince companies to use non-volatile, low-toxic cleaning...
混合式双级矩阵变换器的改进与优化%Improvement and Optimization on Hybrid Two-stage Matrix Converter
Institute of Scientific and Technical Information of China (English)
李生民; 闫晓飞; 钟彦儒
2012-01-01
为了解决混合式双级矩阵变换器拓扑结构与控制策略复杂且直流母线电压波动较大的问题,提出一种改进的直流母线环节升压电路拓扑和带补偿环节的空间矢量脉宽调制策略.改进后的直流环节用常见的直流升压电路取代了原有较复杂的拓扑结构,从而简化了该变换器的控制策略；补偿环节根据直流母线电压波动实时调整逆变级调制系数,补偿电压波动,以期改善输出波形质量.通过Matlab/Simulink建立系统仿真模型,验证了改进混合式双级矩阵变换器理论的正确性以及补偿算法的有效性.%This paper deals with the problems of complex topology and modulation strategy of the hybrid two-stage matrix converter as well as the fluctuation of the dc-bus voltage of the converter. An improvement on the topology of dc-bus and a compensation control scheme are presented. The improved topology uses boost circuit to replace the complex topology and simplifies the modulation strategy. According to the fluctuation of the dc-bus voltage, this scheme adjusts the coefficient of the inverter in time. It can reduce the influence produced by the voltage fluctuation on the output and improve the quantity of the output waveform. A system simulation model is established by Matlab/Simulink and the results showed that the theory of improved hybrid two-stage matrix converter is correct and the compensation control scheme is effective.
Aryl substitution of pentacenes
Directory of Open Access Journals (Sweden)
Andreas R. Waterloo
2014-07-01
Full Text Available A series of 11 new pentacene derivatives has been synthesized, with unsymmetrical substitution based on a trialkylsilylethynyl group at the 6-position and various aryl groups appended to the 13-position. The electronic and physical properties of the new pentacene chromophores have been analyzed by UV–vis spectroscopy (solution and thin films, thermoanalytical methods (DSC and TGA, cyclic voltammetry, as well as X-ray crystallography (for 8 derivatives. X-ray crystallography has been specifically used to study the influence of unsymmetrical substitution on the solid-state packing of the pentacene derivatives. The obtained results add to our ability to better predict substitution patterns that might be helpful for designing new semiconductors for use in solid-state devices.
Mallick, K
2014-01-01
Bone substitute biomaterials are fundamental to the biomedical sector, and have recently benefitted from extensive research and technological advances aimed at minimizing failure rates and reducing the need for further surgery. This book reviews these developments, with a particular focus on the desirable properties for bone substitute materials and their potential to encourage bone repair and regeneration. Part I covers the principles of bone substitute biomaterials for medical applications. One chapter reviews the quantification of bone mechanics at the whole-bone, micro-scale, and non-scale levels, while others discuss biomineralization, osteoductivization, materials to fill bone defects, and bioresorbable materials. Part II focuses on biomaterials as scaffolds and implants, including multi-functional scaffolds, bioceramics, and titanium-based foams. Finally, Part III reviews further materials with the potential to encourage bone repair and regeneration, including cartilage grafts, chitosan, inorganic poly...
Study on fast implementation and optimal methodof gray level co-occurrence matrix%灰度共生矩阵的快速实现和优化方法研究
Institute of Scientific and Technical Information of China (English)
郑红; 李钊; 李俊
2012-01-01
灰度共生矩阵计算具有计算量大、计算延时长等缺点,严重影响计算的实时性.针对此问题在充分分析灰度共生矩阵计算并行性的基础上,提出了快速计算灰度共生矩阵的并行算法和并行体系结构,利用图像中像素之间计算的可并行性,设计多个Processing Elements(PEs)对多个像素进行并行计算,可有效地实现灰度共生矩阵的快速计算.由于嵌入式可重配置硬件平台资源有限,对灰度共生矩阵计算性能进行优化的同时还对资源消耗进行优化.通过对计算延时(latency)和资源消耗(area)的分析,建立新的优化目标函数,实现了性能和资源折衷的优化设计.%Gray level co-occurrence matrix ( GLCM) has the defect of great computation complexity and large computation latency, which seriously affects the real-time property of the calculation. Aiming at this problem, based on the deep analysis of the parallelism of calculating gray level co-occurrence matrix this paper proposes a parallel algorithm and parallel system architecture for calculating GLCM. Utilizing the parallel calculation possibility of image pixels, multiple Processing Elements (PEs) are designed to carry out parallel calculation for multiple pixels, which can achieve rapid calculation of GLCM. Because of the limited hardware resources of the embedded reconfigurable system, besides the optimization of GLCM calculation performance, this paper also achieves the optimization of the resource consumption. A new optimal objective function is proposed through analyzing the computation latency and resource consumption, and the optimal design that achieves the trade-off between calculation performance and resource consumption is realized.
Directory of Open Access Journals (Sweden)
Biswajit Das
2016-03-01
Full Text Available In the present investigation, an in-situ multi-component reinforced aluminium copper alloy based metal matrix composite was fabricated by the flux assisted synthesis (FAS technique. It was found from the optical microscopy analysis that TiC particles are formed in the composite. Further the present research investigates the feasibility and dry machining characteristics of Al–4.5%Cu/5TiC metal matrix composite in CNC milling machine using uncoated solid carbide end mill cutter. The effect of the machining parameters such as feed, cutting speed, depth of cut on the response parameters such as cutting force and COM is determined by using analysis of variance (ANOVA. From the analysis it was found that cutting speed and depth of cut played a major role in affecting cutting force. Multi output optimization of the process was carried out by the application of the Taguchi method with fuzzy logic, and the confirmatory test has revealed the accuracy of the developed model. For predicting the response parameters, regression equations were developed and verified with a number of test cases and it was observed that the percentage error for both responses is less than ±3%, which indicates there is a close agreement between the predicted and the measured results.
Institute of Scientific and Technical Information of China (English)
张远福; 周金贵; 叶正道
2012-01-01
研究矩阵方程AX+BY+CZ=F广义中心对称解,给出了AX+BY+CZ=F的最小二乘广义中心对称解的表达式,导出了AX+BY+CZ=F有广义中心对称解的条件.讨论了在AX+BY+CZ=F最小二乘广义中心对称解集合中求与给定矩阵最佳逼近解.%In this paper, the least-squares solution of the matrix equation AX+BY+CZ=F with respect to Generalized Centro-symmetric Matrices A ,B and C are considered. The general expression of the solution is given and some conditions are derived for the solvability of the matrix equation AX+BY+CZ=F over Generalized Centre— symmetric Matrices. The optimal approximation of the least—squares solution set of AX+BY+CZ=F is provided.
Machining of Metal Matrix Composites
2012-01-01
Machining of Metal Matrix Composites provides the fundamentals and recent advances in the study of machining of metal matrix composites (MMCs). Each chapter is written by an international expert in this important field of research. Machining of Metal Matrix Composites gives the reader information on machining of MMCs with a special emphasis on aluminium matrix composites. Chapter 1 provides the mechanics and modelling of chip formation for traditional machining processes. Chapter 2 is dedicated to surface integrity when machining MMCs. Chapter 3 describes the machinability aspects of MMCs. Chapter 4 contains information on traditional machining processes and Chapter 5 is dedicated to the grinding of MMCs. Chapter 6 describes the dry cutting of MMCs with SiC particulate reinforcement. Finally, Chapter 7 is dedicated to computational methods and optimization in the machining of MMCs. Machining of Metal Matrix Composites can serve as a useful reference for academics, manufacturing and materials researchers, manu...
浮点矩阵向量乘法的FPGA设计与优化%Design and Optimization of Floating-Point Matrix-Vector Multiply for FPGAs
Institute of Scientific and Technical Information of China (English)
薛永江; 宋庆增; 王瑞昆
2013-01-01
In this paper ,we design a matrix-vector multiplier which is based on IEEE-754 (32 bit ,64 bit) floating point data formats ,and the binary tree data flow .The implementation in FPGA platform is pipeline and highly efficient parallel .With Altera EP2C70 as the target device ,detailed study of the design of the hardware size ,clock speed ,capacity and peak GFLOPS .%提出了一种基于IEEE-754的32 bit、64 bit浮点数格式，二叉树数据流（binary tree data flow ）的矩阵向量乘法器。其在FPGA上流水线和高度并行化的高效执行。以Altera公司的EP2C70为实现设备，研究了设计的硬件规模，时钟速度，和峰值GFLOPS能力。
Currency Substitution in Turkey
Directory of Open Access Journals (Sweden)
Ismail H. Genc
2005-01-01
Full Text Available We investigated whether the recent depreciations in the Turkish currency (Lira resulted in the currency substitution away from Lira by using quarterly data over the period from 1987:1 to 2000: 2 with M1 and M2 monetary aggregates and income, interest rate and exchange rate. Other than the variety of monetary aggregates, we tried different ways of including the interest rate into the models to ensure the robustness of our results. Our analysis shows that the currency substitution in fact happened with Lira.
Zhan, Xingzhi
2002-01-01
The main purpose of this monograph is to report on recent developments in the field of matrix inequalities, with emphasis on useful techniques and ingenious ideas. Among other results this book contains the affirmative solutions of eight conjectures. Many theorems unify or sharpen previous inequalities. The author's aim is to streamline the ideas in the literature. The book can be read by research workers, graduate students and advanced undergraduates.
Potential of Metal-Matrix Composites as Superalloy Substitutes
1984-04-01
Engine Construction. Towards a Cycle without Loss: Cobalt in the Aircraft Industry. Gas Turbine Engine Design Considerations as Related to Alloys of...Developments to Reduce Strategic Materials Usage. Practical Implications of the Use of Alumlnlde Coatings for the Corrosion Protection of Superalloys in Gas ...Aaroapatlalas (ONERA) BP72, 92)22 Chatlllon, Cadax, Franca ABSTRACT ’The potential of metal-matrlx coaposltas aa qaa- turbina blada material« has
Directory of Open Access Journals (Sweden)
R. Arokiadass
2012-04-01
Full Text Available Highly automated CNC end milling machines in manufacturing industry requires reliable model for prediction of tool flank wear. This model later can be used to predict the tool flank wear (VBmax according to the process parameters. In this investigation an attempt was made to develop an empirical relationship to predict the tool flank wear (VBmax of carbide tools while machining LM25 Al/SiCp incorporating the process parameters such as spindle speed (N, feed rate (f, depth of cut (d and various % wt. of silicon carbide (S. Response surface methodology (RSM was applied to optimizing the end milling process parameters to attain the minimum tool flank wear. Predicted values obtained from the developed model and experimental results are compared, and error <5 percent is observed. In addition, it is concluded that the flank wear increases with the increase of SiCp percentage weight in the MMC.
Institute of Scientific and Technical Information of China (English)
李永华; 唐先超
2014-01-01
近年来国内民航迅速发展，机场的新建、扩建和航空运输量的持续增长使得机场噪声污染事件不仅持续上升，而且噪声污染程度也日益加重，因而强化机场附近噪声污染的监测对机场建设及其环境评估十分重要。针对机场噪声污染监测问题，提出一种基于非负矩阵分解(NMF)方法对机场噪声监测点布局问题进行优化求解。该方法以大量网格点作为候选监测点，对单个飞机噪声事件候选监测点的噪声值所形成的矩阵按非负矩阵分解进行区域划分，得到噪声影响子区域。进一步以各子区域的中心点作为该区域的噪声影响代表点，以此确定机场噪声监测点数目和位置。研究结果表明所获得的解比贪心算法得到的解更优，需要的监测点更少。%With the rapid development of domestic civil aviation in recent years, noise pollution of airports is becoming a serious problem. Thus, strengthening the noise monitoring in the airport vicinity is very important for airport construction and environmental evaluation. Aiming at the monitoring of airport noise pollution, an optimization method based on non-negative matrix factorization (NMF) is put forward to optimize the layout of the noise monitoring sites. In this method, large number of the grid nodes is employed as the candidate monitoring points, and the non-negative matrix composed of the noise values from single flight event at the candidate monitoring points is formed. Then, the non-negative matrix is factorized to obtain the effective subdivision of noise. Furthermore, the location and number of the noise monitoring sites are determined by the representative central point of the effective subdivisions. It is shown that this method needs fewer monitoring locating sites and can get better results than the greedy algorithm.
Institute of Scientific and Technical Information of China (English)
Sophia
2007-01-01
@@ Energy crisis has become great challenge to the whole world.As the vehicle population keeps soaring in China,effectie countermeasures should be taken timely to deal with global energy crisis.There are two ways out:one is to substitute and one is to save.
Simulating currency substitution bias
M. Boon (Martin); C.J.M. Kool (Clemens); C.G. de Vries (Casper)
1989-01-01
textabstractThe sign and size of estimates of the elasticity of currency substitution critically depend on the definition of the oppurtunity costs of holding money. We investigate possible biases by means of Monte Carlo experiments, as sufficient real data are not available.
Prioritizing substitution of organic solvents in industrial cleaning processes
DEFF Research Database (Denmark)
Rasmussen, Pia Brunn; Jacobsen, Thomas
1997-01-01
A method for prioritizing the substitution of volatile organic compounds (VOC) used in industrial cleaning processes is developed. The result is a matrix, which, if all information can be obtained, gives a comprehensive description of the effects, exposure and emission of VOC, as well...
Dermal Matrices and Bioengineered Skin Substitutes: A Critical Review of Current Options
Directory of Open Access Journals (Sweden)
Heidi Debels, MD
2015-01-01
Conclusions: Skin substitutes are a useful tool in plastic and reconstructive surgery practices as an alternative to skin grafts. In the choice of substitute, the general plastic surgery principle of replacing like tissue with like tissue seems to be still standing, and products most resembling the natural dermal extracellular matrix should be preferred.
Bhatia, Rajendra
1997-01-01
A good part of matrix theory is functional analytic in spirit. This statement can be turned around. There are many problems in operator theory, where most of the complexities and subtleties are present in the finite-dimensional case. My purpose in writing this book is to present a systematic treatment of methods that are useful in the study of such problems. This book is intended for use as a text for upper division and gradu ate courses. Courses based on parts of the material have been given by me at the Indian Statistical Institute and at the University of Toronto (in collaboration with Chandler Davis). The book should also be useful as a reference for research workers in linear algebra, operator theory, mathe matical physics and numerical analysis. A possible subtitle of this book could be Matrix Inequalities. A reader who works through the book should expect to become proficient in the art of deriving such inequalities. Other authors have compared this art to that of cutting diamonds. One first has to...
Smart Substitutions for Healthy Cooking
... Recognition & Awards Healthy Workplace Food and Beverage Toolkit Smart Substitutions Updated:Dec 16,2016 Healthy eating doesn’ ... mean giving up all the foods you love! Smart substitutions can help you maintain an overall healthy ...
修正协方差阵的投资组合方案及其稳定性%Optimal portfolio project with modified covariance matrix and its stability
Institute of Scientific and Technical Information of China (English)
储晨; 方兆本
2011-01-01
The reasons why the risk of optimal portfolio is unstable was analyzed.Based on this analysis a new method was tried,which was proposed by the previous researchers,to dispose the sample covariance matrix based on random matrix theory (RMT),to get a better result.Generally,we first give more sufficient and practical evidence to support the method's reasonableness and power,then apply this idea to simulate the “real investment”,using real data of the Chinese stock market.It is found that the results have better mean return and stability than those of the traditional method,and can be explained by the analysis of the prediction to the risk proposed by the previous researchers.%分析了最优化投资组合不稳定的原因,在此基础上,推广了由前人提出的一个新方法,即根据随机矩阵定理(RMT)对样本协差阵进行变化以得到一个更好的投资方案.首先对该方法中未证明的部分给出了更充分的实证理由,并运用这种思想,结合中国证券市场的实际数据,来模拟“真实的投资”.而这种方法得到的投资方案,较之传统方法有较好的收益率和方差,且可被前人对风险预测的分析方法所解释.
Belitsky, A V
2016-01-01
The Operator Product Expansion for null polygonal Wilson loop in planar maximally supersymmetric Yang-Mills theory runs systematically in terms of multiparticle pentagon transitions which encode the physics of excitations propagating on the color flux tube ending on the sides of the four-dimensional contour. Their dynamics was unravelled in the past several years and culminated in a complete description of pentagons as an exact function of the 't Hooft coupling. In this paper we provide a solution for the last building block in this program, the SU(4) matrix structure arising from internal symmetry indices of scalars and fermions. This is achieved by a recursive solution of the Mirror and Watson equations obeyed by the so-called singlet pentagons and fixing the form of the twisted component in their tensor decomposition. The non-singlet, or charged, pentagons are deduced from these by a limiting procedure.
Random matrix theory and robust covariance matrix estimation for financial data
Frahm, G; Frahm, Gabriel; Jaekel, Uwe
2005-01-01
The traditional class of elliptical distributions is extended to allow for asymmetries. A completely robust dispersion matrix estimator (the `spectral estimator') for the new class of `generalized elliptical distributions' is presented. It is shown that the spectral estimator corresponds to an M-estimator proposed by Tyler (1983) in the context of elliptical distributions. Both the generalization of elliptical distributions and the development of a robust dispersion matrix estimator are motivated by the stylized facts of empirical finance. Random matrix theory is used for analyzing the linear dependence structure of high-dimensional data. It is shown that the Marcenko-Pastur law fails if the sample covariance matrix is considered as a random matrix in the context of elliptically distributed and heavy tailed data. But substituting the sample covariance matrix by the spectral estimator resolves the problem and the Marcenko-Pastur law remains valid.
LONG TERM EVOLUTION OF BONE RECONSTRUCTION WITH BONE GRAFT SUBSTITUTES
Directory of Open Access Journals (Sweden)
O. V. Martynenko
2017-06-01
Full Text Available The review involves clinical and experimental data, constitutive modeling, and computational investigations towards an understanding on how mechanical cyclic loads for long periods of time affect damage evolution in a reconstructed bone, as well as, lifetime reduction of bone graft substitutes after advanced core decompression. The outcome of the integrated model discussed in this paper will be how damage growth in femur after advanced core decompression subjected to mechanical cyclic loading under creep and fatigue conditions may be controlled in order to optimize design and processing of bone graft substitutes, and extend lifetime of bone substitutes.
Optimal taxation with household production
DEFF Research Database (Denmark)
Kleven, Henrik Jacobsen; Richter, Wolfram F.; Sørensen, Peter Birch
2000-01-01
This paper suggests that the optimal tax system should favour market-produced services which are close substitutes for home-produced services. First, we modify the classical Corlett-Hague rule for optimal commodity taxation by showing that it may be optimal to impose a relatively low tax rate...... on consumer services even if such services are complements to leisure. Second, we find that when services and other goods are equally substitutable for leisure, so that uniform commodity taxation would be optimal in the absence of home production, the optimal tax structure will certainly involve a relatively...
Institute of Scientific and Technical Information of China (English)
T.RAJMOHAN; K.PALANIKUMAR; M.KATHIRVEL
2012-01-01
Taguchi method with grey relational analysis was used to optimize the machining parameters with multiple performance characteristics in drilling hybrid metal matrix A1356/SiC-mica composites.Experiments were conducted on a computer numerical control vertical machining centre and L18 orthogonal array was chosen for the experiments.The drilling parameters namely spindle speed,feed rate,drill type and mass fraction of mica were optimized based on the multiple performance characteristics including thrust force,surface roughness,tool wear and burr height (exit).The results show that the feed rate and the type of drill are the most significant factors which affect the drilling process and the performance in the drilling process can be effectively improved by using this approach.%采用Taguchi方法和灰色关联分析对A1356/SiC-云母混合金属基复合材料的钻削工艺参数进行优化.实验采用L18正交阵列,在计算机的控制立式机床上进行.考察的钻削性能指标包括轴向力、表面粗糙度、刀具磨损和毛刺高度,对影响这些性能的钻削工艺参数进行了优化,包括轴转数、给进速度、钻头类型和云母质量分数.结果表明:给进速度和钻头类型是影响钻削过程的重要因素,通过这种方法可以有效地改进钻削工艺的性能.
Image registration based on matrix perturbation analysis using spectral graph
Institute of Scientific and Technical Information of China (English)
Chengcai Leng; Zheng Tian; Jing Li; Mingtao Ding
2009-01-01
@@ We present a novel perspective on characterizing the spectral correspondence between nodes of the weighted graph with application to image registration.It is based on matrix perturbation analysis on the spectral graph.The contribution may be divided into three parts.Firstly, the perturbation matrix is obtained by perturbing the matrix of graph model.Secondly, an orthogonal matrix is obtained based on an optimal parameter, which can better capture correspondence features.Thirdly, the optimal matching matrix is proposed by adjusting signs of orthogonal matrix for image registration.Experiments on both synthetic images and real-world images demonstrate the effectiveness and accuracy of the proposed method.
2010-07-01
... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted pyridine coupled with... Specific Chemical Substances § 721.10034 Substituted pyridine coupled with diazotized substituted... as substituted pyridine coupled with diazotized substituted nitrobenzonitrile, diazotized...
Institute of Scientific and Technical Information of China (English)
邢彦富; 孔娅; 方兴
2011-01-01
建筑设计方案的优选是一项复杂的决策过程。运用模糊一致矩阵理论，建立建筑设计方案优选的数学模型，对设计方案进行多阂素综合评价，克服了建筑设计方案选择中影响因素的粗略性以及人为主观判断的随意性，从而获得良好的经济效益和社会效益。实例表明，采用该方法进行建筑设计方案的优选是可行的、有效的。%It is a complicated decision process for the optimization of architectural design scheme. The paper adopts the fuzzy consistent matrix theory, the indicator system of the architectural design scheme was established, has the comprehensive evaluation on the architectural design scheme, overcomes the rudeness of the influential factors in the architectural scheme selection, and the casualness of personal objective judgment, finally get the best benefits from the economic and social. A case shows that the method is reasonable and effective to evaluate architectural design scheme.
Energy Technology Data Exchange (ETDEWEB)
Penning, Thomas D.; Zhu, Gui-Dong; Gong, Jianchun; Thomas, Sheela; Gandhi, Viraj B.; Liu, Xuesong; Shi, Yan; Klinghofer, Vered; Johnson, Eric F.; Park, Chang H.; Fry, Elizabeth H.; Donawho, Cherrie K.; Frost, David J.; Buchanan, Fritz G.; Bukofzer, Gail T.; Rodriguez, Luis E.; Bontcheva-Diaz, Velitchka; Bouska, Jennifer J.; Osterling, Donald J.; Olson, Amanda M.; Marsh, Kennan C.; Luo, Yan; Giranda, Vincent L. (Abbott)
2010-06-21
We have developed a series of phenylpyrrolidine- and phenylpiperidine-substituted benzimidazole carboxamide poly(ADP-ribose) polymerase (PARP) inhibitors with excellent PARP enzyme potency as well as single-digit nanomolar cellular potency. These efforts led to the identification of (S)-2-(2-fluoro-4-(pyrrolidin-2-yl)phenyl)-1H-benzimidazole-4-carboxamide (22b, A-966492). Compound 22b displayed excellent potency against the PARP-1 enzyme with a K{sub i} of 1 nM and an EC{sub 50} of 1 nM in a whole cell assay. In addition, 22b is orally bioavailable across multiple species, crosses the blood-brain barrier, and appears to distribute into tumor tissue. It also demonstrated good in vivo efficacy in a B16F10 subcutaneous murine melanoma model in combination with temozolomide and in an MX-1 breast cancer xenograft model both as a single agent and in combination with carboplatin.
Intertemporal Substitution in Macroeconomics
N. Gregory Mankiw; Rotemberg, Julio J.; Lawrence H. Summers
1982-01-01
Modern neoclassical theories of the business cycle posit that aggregate fluctuations in consumption and employment are the consequence of dynamic optimizing behavior by economic agents who face no quantity constraint. In this paper, we estimate an explicit model :f this type. In particular, we assume that the observed fluctuations correspond to the decisions of an optimizing representative individual. This individual has a stable utility function which is additively separable over time but no...
Institute of Scientific and Technical Information of China (English)
王新民
2011-01-01
In this paper, a optimized method for the characteristic values, the characteristic vectors and the resemble diagonal form of a matrix is studied. With the optimized method, we can obtain the characteristic values and the characteristic vectors, judge the diagonalization of the matrix, write out the reversible matrix T satisfying T-1AT is a diagonal matrix if A is a diagonalization matrix at the same time more easily.%研究了矩阵的特征根与特征向量及其相似对角形的优化求法.优化了文[1]的方法,只要对矩阵A的特征矩阵λE-A施行初等变换化为对角形,即可同时求出A的特征根与特征向量,判断A是否可对角化.在A可对角化时,可直接写出相应的可逆矩阵T,使T-1AT为对角形矩阵.
Kargın, Levent; Kurt, Veli
2015-01-01
In this study, obtaining the matrix analog of the Euler's reflection formula for the classical gamma function we expand the domain of the gamma matrix function and give a infinite product expansion of sinπxP. Furthermore we define Riemann zeta matrix function and evaluate some other matrix integrals. We prove a functional equation for Riemann zeta matrix function.
Thermogram No Substitute for Mammogram
... Products Vaccines, Blood & Biologics Animal & Veterinary Cosmetics Tobacco Products For Consumers Home For Consumers Consumer Updates Thermogram No Substitute for Mammogram Share Tweet Linkedin Pin it More ...
Substitute Valuations: Generation and Structure
Hajek, Bruce
2007-01-01
Substitute valuations (in some contexts called gross substitute valuations) are prominent in combinatorial auction theory. An algorithm is given in this paper for generating a substitute valuation through Monte Carlo simulation. In addition, the geometry of the set of all substitute valuations for a fixed number of goods K is investigated. The set consists of a union of polyhedrons, and the maximal polyhedrons are identified for K=4. It is shown that the maximum dimension of the maximal polyhedrons increases with K nearly as fast as two to the power K.
Structure and Substitutions in Fluorapatite
Directory of Open Access Journals (Sweden)
Leroy N.
2001-11-01
Full Text Available Fluorapatite, Ca10(PO46F2. is a widely spread form of calcium phosphate present particularly in biological material. Human hard tissues contain crystals structurally related to apatite. Fluoride can be found in various natural sources and is also used for its beneficial action in caries prevention. Fluorapatite belongs to the spatial group P63/m (C6h2 and consists of 3 ions: F-, Ca2+, PO43-. In the present paper, we have carried out a crystallographic study of the fluorapatite structure and of the changes induced by the substitutions. The fluorapatite structure and the presence of a large number of ionic bonds make fluorapatite a very suitable host for many substitutents, some of them harmless for the human organism, some not. According to the substitution site, we can describe four types of substitution. The F- substitution, also called Type A substitution, is the main one, and the best known. Only the Ca2+ substitution implies changes in the crystal structure. However, some questions remain, in particular for the PO43- substitution, which is the main substitution present in the biological calcium phosphates.
Optimization of the Formula of Healthy Sugar Substitute using Mixture Design%采用混料设计优化保健型餐桌代糖的配方研究
Institute of Scientific and Technical Information of China (English)
骆海平; 吴胜旭; 徐勇; 寇秀颖
2012-01-01
In this paper, sensory evaluation was used for optimiazation of formula of a healthy sugar substitute by mixture design model. The best formula was determined as: glucose (21.3%), xylitol (23.3%), maltodextrin (55.4%). The sensory sore was 4.66.%以感官指标为主要评价指标,采用混料设计法优化以三氯蔗糖为主甜味剂,葡萄糖、木糖醇、麦芽糊精为主要填充料的保健型复合餐桌代糖的配方.最佳配方为:葡萄糖的添加水平为21.3％、木糖醇为23.3％、麦芽糊精为55.4％.感观评价得分为4.66.
Zhao, Zhengji
We study the reduced density matrix method, a variational approach for electronic structure calculations based on the two-body reduced density matrix. This method minimizes the ground state energy with respect to the two-body reduced density matrix subject to some conditions which it must satisfy, known as N-representability conditions. The resulting optimization problem is a semidefinite program, a convex optimization problem for which computational methods have greatly advanced during the past decade. Two significant advances are reported in this thesis. First, we formulate the reduced density matrix method using the dual formulation of semidefinite programming instead of the previously-used primal one; this results in substantial computational savings and makes it possible to study larger systems than was done previously. Second, in addition to the previously-used P, Q and G conditions we investigate a pair of positive semidefinite conditions that has a three-index form; we call them the T1 and T2 conditions. We find that the inclusion of the T1 and T2 conditions gives a significant improvement over results previously obtained using only the P, Q and G conditions; and provides in all cases we have studied (47 molecules) more accurate results than other more familiar methods: Hartree-Fork; 2nd order Moller-Plesset method (MP2), singly and doubly substituted configuration interaction (SDCI), quadratic configuration interaction including single and double substitutions (QCISD), Brueckner doubles (with triples) (BD(T)) and coupled cluster singles and doubles with perturbational treatment of triples (CCSD(T)).
Composite bone substitutes prepared by two methods
Lee, Hoe Y.
A variety of ceramics and polymers exists that can be used as bone substitute materials with desirable properties such as biocompatibility and osteoconductivity. A key feature missing in these bone substitutes, or scaffolds, is the ability to bear loads. This work explored two methods for solving this problem. The first used cancellous bone taken from bovine femoral bone to create a natural scaffold through a heat treating process that eliminated the organic components and sintered the bone minerals, known as hydroxyapatite, together. The strength and Young's modulus of the natural scaffold were greatly improved after polymer infiltration with polymethylmethacrylate. Unfortunately, compression testing revealed that there was not a good interfacial bond between the mineral and polymer phases. The second method employed a freeze-casting technique to create synthetic hydroxyapatite scaffolds that have an aligned lamellar microstructure. By varying the amount of hydroxyapatite in the initial slurry mixture and the cooling rate, synthetic scaffolds with a range of porosities and strengths was produced. The highest solid loading and fastest cooling rate produced a scaffold with a strength and modulus approaching that of cortical bone. Further study is required to produce a two phase composite that is chemically bonded together for optimal performance. The synthetic scaffolds, with their tunable mechanical properties and ease of fabrication, make them a promising material for a load-bearing bone substitute.
Yan, Wang-Ji; Katafygiotis, Lambros S.
2016-10-01
The problem of stochastic system identification utilizing response measurements only is considered in this paper. A negative log-likelihood function utilized to determine the posterior most probable parameters and their associated uncertainties is formulated by incorporating transmissibility matrix concept, random matrix theory and Bayes’ theorem. A numerically iterative coupled method involving the optimization of the parameters in groups is proposed so as to reduce the dimension of the numerical optimization problem involved. The initial guess for the parameters to be optimized is also properly estimated through asymptotic analysis. One novel feature of the proposed method is to avoid repeated time-consuming evaluation of the determinant and inverse of the covariance matrix during optimization due to exploring the statistical properties of the trace of Wishart matrix. The proposed method requires no information about the model of the external input. The theory described in this work is illustrated with synthetic data and field data measured from a laboratory model installed with wireless sensors.
Matrix Factorization for Evolution Data
Directory of Open Access Journals (Sweden)
Xiao-Yu Huang
2014-01-01
Full Text Available We study a matrix factorization problem, that is, to find two factor matrices U and V such that R≈UT×V, where R is a matrix composed of the values of the objects O1,O2,…,On at consecutive time points T1,T2,…,Tt. We first present MAFED, a constrained optimization model for this problem, which straightforwardly performs factorization on R. Then based on the interplay of the data in U, V, and R, a probabilistic graphical model using the same optimization objects is constructed, in which structural dependencies of the data in these matrices are revealed. Finally, we present a fitting algorithm to solve the proposed MAFED model, which produces the desired factorization. Empirical studies on real-world datasets demonstrate that our approach outperforms the state-of-the-art comparison algorithms.
Cache oblivious storage and access heuristics for blocked matrix-matrix multiplication
Bock, Nicolas; SaÅek, PaweÅ; Niklasson, Anders M N; Challacombe, Matt
2008-01-01
We investigate effects of ordering in blocked matrix--matrix multiplication. We find that submatrices do not have to be stored contiguously in memory to achieve near optimal performance. Instead it is the choice of multiplication ordering that leads to a speedup of up to four times for small block sizes. This is in contrast to results for single matrix elements showing that contiguous memory allocation quickly becomes irrelevant as the blocksize increases.
The Matrix Element Method and Vector-Like Quark Searches
Morrison, Benjamin
2016-01-01
In my time at the CERN summer student program, I worked on applying the matrix element method to vector-like quark identification. I worked in the ATLAS University of Geneva group under Dr. Olaf Nackenhorst. I developed automated plotting tools with ROOT, a script for implementing and optimizing generated matrix element calculation code, and kinematic transforms for the matrix element method.
Currency substitution in Eastern Europe
van Aarle, B.; Budina, N.
1995-01-01
Monetary instability during the transition process from a command economy to a market economy has induced a considerable increase in currency substitution in Eastern Europe. Currency substitution itself affects monetary stability since it reduces the stability of velocity. This paper investigates cu
Displacement, Substitution, Sublimation: A Bibliography.
Pedrini, D. T.; Pedrini, Bonnie C.
Sigmund Freund worked with the mechanisms of displacement, substitution, and sublimation. These mechanisms have many similarities and have been studied diagnostically and therapeutically. Displacement and substitution seem to fit in well with phobias, hysterias, somatiyations, prejudices, and scapegoating. Phobias, prejudices, and scapegoating…
Substitute Teachers: The Professional Contradiction.
Shreeve, William C.; And Others
The substitute teacher's public image was investigated by means of an informal survey of part-time and full-time teachers in Washington. Survey results revealed that working conditions appeared to be the largest factor in damaging the self-image of most substitute teachers. The majority of full-time teachers and administrators surveyed were…
Matrix Completion from Noisy Entries
Keshavan, Raghunandan H; Oh, Sewoong
2009-01-01
Given a matrix M of low-rank, we consider the problem of reconstructing it from noisy observations of a small, random subset of its entries. The problem arises in a variety of applications, from collaborative filtering (the `Netflix problem') to structure-from-motion and positioning. We study a low complexity algorithm introduced by Keshavan et al.(2009), based on a combination of spectral techniques and manifold optimization, that we call here OptSpace. We prove performance guarantees that are order-optimal in a number of circumstances.
Stochastic optimization methods
Marti, Kurt
2005-01-01
Optimization problems arising in practice involve random parameters. For the computation of robust optimal solutions, i.e., optimal solutions being insensitive with respect to random parameter variations, deterministic substitute problems are needed. Based on the distribution of the random data, and using decision theoretical concepts, optimization problems under stochastic uncertainty are converted into deterministic substitute problems. Due to the occurring probabilities and expectations, approximative solution techniques must be applied. Deterministic and stochastic approximation methods and their analytical properties are provided: Taylor expansion, regression and response surface methods, probability inequalities, First Order Reliability Methods, convex approximation/deterministic descent directions/efficient points, stochastic approximation methods, differentiation of probability and mean value functions. Convergence results of the resulting iterative solution procedures are given.
Sparse Planar Array Synthesis Using Matrix Enhancement and Matrix Pencil
Directory of Open Access Journals (Sweden)
Mei-yan Zheng
2013-01-01
Full Text Available The matrix enhancement and matrix pencil (MEMP plays important roles in modern signal processing applications. In this paper, MEMP is applied to attack the problem of two-dimensional sparse array synthesis. Firstly, the desired array radiation pattern, as the original pattern for approximating, is sampled to form an enhanced matrix. After performing the singular value decomposition (SVD and discarding the insignificant singular values according to the prior approximate error, the minimum number of elements can be obtained. Secondly, in order to obtain the eigenvalues, the generalized eigen-decomposition is employed on the approximate matrix, which is the optimal low-rank approximation of the enhanced matrix corresponding to sparse planar array, and then the ESPRIT algorithm is utilized to pair the eigenvalues related to each dimension of the planar array. Finally, element positions and excitations of the sparse planar array are calculated according to the correct pairing of eigenvalues. Simulation results are presented to illustrate the effectiveness of the proposed approach.
Cache oblivious storage and access heuristics for blocked matrix-matrix multiplication
Energy Technology Data Exchange (ETDEWEB)
Bock, Nicolas [Los Alamos National Laboratory; Rubensson, Emanuel H [Los Alamos National Laboratory; Niklasson, Anders M N [Los Alamos National Laboratory; Challacombe, Matt [Los Alamos National Laboratory; Salek, Pawel [SWEDEN
2008-01-01
The authors investigate effects of ordering in blocked matrix-matrix multiplication. They find that submatrices do not have to be stored contiguously in memory in order to achieve near optimal performance. They also find a good choice of execution order of submatrix operations can lead to a speedup of up to four times for small block sizes.
Thermodynamic studies on charge-coupled substituted synthetic monazite
Rawat, D.; Phapale, S.; Mishra, R.; Dash, S.
2017-04-01
Phosphate-based monazite ceramic is considered worldwide as a potential crystalline host matrix for immobilization of long-lived tri- and tetra-valent actinides present in high-level nuclear waste. Monazite is chemically stable with respect to the leaching processes and has high radiation stability. The present paper describes the influence of charged coupled (Ca2+, Th4+) substitution in place of La3+ on thermodynamic stability of synthetic monazite ceramics. XRD-analysis of Ca, Th substituted LaPO4 viz., La1-xCax/2Thx/2PO4 (0 ≤ x ≤ 1) points to the formation of ideal solid-solution in the entire range of composition. However, thermodynamic analysis indicates deviation from ideal solid-solution with a minima at x = 0.25. The substituted La1-xCax/2Thx/2PO4 system is found to be iso-entropic and stabilized mainly by enthalpy. Enthalpies of formation as a function of Ca2+, Th4+ substitution were analysed to provide insights into the development of thermodynamically stable nuclear waste matrix.
Trifluoromethyl-substituted tetrathiafulvalenes
Directory of Open Access Journals (Sweden)
Olivier Jeannin
2015-05-01
Full Text Available A series of tetrathiafulvalenes functionalized with one or two trifluoromethyl electron-withdrawing groups (EWG is obtained by phosphite coupling involving CF3-substituted 1,3-dithiole-2-one derivatives. The relative effects of the EWG such as CF3, CO2Me and CN on the TTF core were investigated from a combination of structural, electrochemical, spectrochemical and theoretical investigations. Electrochemical data confirm the good correlations between the first oxidation potential of the TTF derivatives and the σmeta Hammet parameter, thus in the order CO2Me 3 3, where, as in TTF itself, the low energy absorption band is essentially attributable to a HOMO→LUMO + 1 transition. Despite relatively high oxidation potentials, these donor molecules with CF3 EWG can be involved in charge transfer complexes or cation radical salts, as reported here for the CF3-subsituted EDT-TTF donor molecule. A neutral charge transfer complex with TCNQ, (EDT-TTF-CF32(TCNQ was isolated and characterized through alternated stacks of EDT-TTF-CF3 dimers and TCNQ in the solid state. A radical cation salt of EDT-TTF-CF3 is also obtained upon electrocrystallisation in the presence of the FeCl4− anion. In this salt, formulated as (EDT-TTF-CF3(FeCl4, the (EDT-TTF-CF3+• radical cations are associated two-by-two into centrosymmetric dyads with a strong pairing of the radical species in a singlet state.
SINGLE-PERIOD TWO-PRODUCT INVENTORY MODEL WITH SUBSTITUTION:SOLUTION AND PROPERTIES
Institute of Scientific and Technical Information of China (English)
Lianqiao CAI; Jian CHEN; Houmin YAN
2004-01-01
In this paper, we study a single-period two-product inventory model with stochastic demands and downward substitution. The optimal order quantities are presented and some properties are provided. Comparing with newsboy model, we prove that both the profit and the fill rate can be improved by using the substitution policy.
Pricing and Warranty Decisions of Substitutable Products for a Fuzzy Two-Echelon Supply Chain
National Research Council Canada - National Science Library
Wang, Yongzhao
2017-01-01
This paper considers the optimal decisions of pricing and warranty level for substitutable products in a fuzzy supply chain environment, where the consumer demands, manufacturing costs, and warranty...
Vitreous substitutes: challenges and directions
Institute of Scientific and Technical Information of China (English)
Qian-Ying; Gao; Yue; Fu; Yan-Nian; Hui
2015-01-01
The natural vitreous body has a fine structure and complex functions. The imitation of the natural vitreous body by vitreous substitutes is a challenging work for both researchers and ophthalmologists. Gases, silicone oil, heavy silicone oil and hydrogels, particularly the former two vitreous substitutes are clinically widely used with certain complications. Those, however, are not real artificial vitreous due to lack of structure and function like the natural vitreous body. This article reviews the situations, challenges, and future directions in the development of vitreous substitutes, particularly the experimental and clinical use of a new artificial foldable capsular vitreous body.
Glass matrix composite material prepared with waste foundry sand
Directory of Open Access Journals (Sweden)
ZHANG Zhao-shu
2006-11-01
Full Text Available The technology of glass matrix of the composite material manufactured through a sintering process and using waste foundry sand and waste glass as the main raw materials was studied. The effects of technological factors on the performance of this material were studied. The results showed that this composite material is formed with glass as matrix, core particulate as strengthening material, it has the performance of glass and ceramics, and could be used to substitute for stone.
Glass matrix composite material prepared with waste foundry sand
Institute of Scientific and Technical Information of China (English)
ZHANG Zhao-shu; XIA Ju-pei; ZHU Xiao-qin; LIU Fan; HE Mao-yun
2006-01-01
The technology of glass matrix of the composite material manufactured through a sintering process and using waste foundry sand and waste glass as the main raw materials was studied. The effects of technological factors on the performance of this material were studied. The results showed that this composite material is formed with glass as matrix, core particulate as strengthening material, it has the performance of glass and ceramics, and could be used to substitute for stone.
Factor substitution in nursing homes.
Cawley, John; Grabowski, David C; Hirth, Richard A
2006-03-01
This paper studies factor substitution in one important sector: the nursing home industry. Specifically, we measure the extent to which nursing homes substitute materials for labor when labor becomes relatively more expensive. From a policy perspective, factor substitution in this market is important because materials-intensive methods of care are associated with greater risks of morbidity and mortality among nursing home residents. Studying longitudinal data from 1991 to 2000 on nearly every nursing home in the United States, we use the method of instrumental variables (IV) to address measurement error in nursing home wages. The results from the IV models yield evidence of factor substitution: higher nursing home wages are associated with greater use of psychoactive drugs and lower quality.
Nucleophilic Substitution by Benzodithioate Anions.
Bonnans-Plaisance, Chantal; Gressier, Jean-Claude
1988-01-01
Describes a two-session experiment designed to provide a good illustration of, and to improve student knowledge of, the Grignard reaction and nucleophilic substitution. Discusses the procedure, experimental considerations, and conclusion of this experiment. (CW)
Ubiquitination of specific mitochondrial matrix proteins.
Lehmann, Gilad; Ziv, Tamar; Braten, Ori; Admon, Arie; Udasin, Ronald G; Ciechanover, Aaron
2016-06-17
Several protein quality control systems in bacteria and/or mitochondrial matrix from lower eukaryotes are absent in higher eukaryotes. These are transfer-messenger RNA (tmRNA), The N-end rule ATP-dependent protease ClpAP, and two more ATP-dependent proteases, HslUV and ClpXP (in yeast). The lost proteases resemble the 26S proteasome and the role of tmRNA and the N-end rule in eukaryotic cytosol is performed by the ubiquitin proteasome system (UPS). Therefore, we hypothesized that the UPS might have substituted these systems - at least partially - in the mitochondrial matrix of higher eukaryotes. Using three independent experimental approaches, we demonstrated the presence of ubiquitinated proteins in the matrix of isolated yeast mitochondria. First, we show that isolated mitochondria contain ubiquitin (Ub) conjugates, which remained intact after trypsin digestion. Second, we demonstrate that the mitochondrial soluble fraction contains Ub-conjugates, several of which were identified by mass spectrometry and are localized to the matrix. Third, using immunoaffinity enrichment by specific antibodies recognizing digested ubiquitinated peptides, we identified a group of Ub-modified matrix proteins. The modification was further substantiated by separation on SDS-PAGE and immunoblots. Last, we attempted to identify the ubiquitin ligase(s) involved, and identified Dma1p as a trypsin-resistant protein in our mitochondrial preparations. Taken together, these data suggest a yet undefined role for the UPS in regulation of the mitochondrial matrix proteins.
Thomas, S K; Lilley, C E; Latchman, D S; Coffin, R S
1999-09-01
Herpes simplex virus (HSV) has often been suggested for development as a vector, particularly for the nervous system. Considerable evidence has shown that for use of HSV as a vector, immediate-early (IE) gene expression must be minimized or abolished, otherwise such vectors are likely to be highly cytotoxic. Mutations of vmw65 which abolish IE promoter transactivating activity may also be included to reduce IE gene expression generally. However, when vmw65 mutations are combined with an IE gene deletion, such viruses are hard to propagate, even on cells which otherwise complement the IE gene deletion effectively. We have found that vmw65 mutants can be effectively grown on cell lines expressing equine herpesvirus 1 gene 12, a non-HSV homologue of vmw65 with little sequence similarity to its HSV counterpart. This prevents repair by homologous recombination of vmw65 mutations in the virus, which would occur if mutations were complemented by vmw65 itself. The gene 12 protein is not packaged into HSV virions, which is important if viruses grown on such cells are to be used as vectors. These results not only further strengthen the evidence for direct functional homology between and similar modes of action of the two proteins but have allowed the generation of gene 12-containing cell lines in which ICP4 and ICP27 expression is induced by virus infection (probably by ICP0) and which give efficient growth of viruses deficient in ICP27, ICP4, and vmw65 (the viruses also have ICP34.5/ORFP deleted). Efficient growth of such viruses has not previously been possible. As these viruses are highly deficient in IE gene expression generally, such virus-cell line combinations may provide an alternative to HSV vectors with deletions of all four of the regulatory IE genes which, for optimal growth, require cell lines containing all four IE genes but which are hard to generate due to the intrinsic cytotoxicity of each of the proteins.
DEFF Research Database (Denmark)
Petersen, Kaare Brandt; Pedersen, Michael Syskind
Matrix identities, relations and approximations. A desktop reference for quick overview of mathematics of matrices.......Matrix identities, relations and approximations. A desktop reference for quick overview of mathematics of matrices....
Matrix with Prescribed Eigenvectors
Ahmad, Faiz
2011-01-01
It is a routine matter for undergraduates to find eigenvalues and eigenvectors of a given matrix. But the converse problem of finding a matrix with prescribed eigenvalues and eigenvectors is rarely discussed in elementary texts on linear algebra. This problem is related to the "spectral" decomposition of a matrix and has important technical…
Vibrational Density Matrix Renormalization Group.
Baiardi, Alberto; Stein, Christopher J; Barone, Vincenzo; Reiher, Markus
2017-08-08
Variational approaches for the calculation of vibrational wave functions and energies are a natural route to obtain highly accurate results with controllable errors. Here, we demonstrate how the density matrix renormalization group (DMRG) can be exploited to optimize vibrational wave functions (vDMRG) expressed as matrix product states. We study the convergence of these calculations with respect to the size of the local basis of each mode, the number of renormalized block states, and the number of DMRG sweeps required. We demonstrate the high accuracy achieved by vDMRG for small molecules that were intensively studied in the literature. We then proceed to show that the complete fingerprint region of the sarcosyn-glycin dipeptide can be calculated with vDMRG.
Ubiquitination of specific mitochondrial matrix proteins
Energy Technology Data Exchange (ETDEWEB)
Lehmann, Gilad [The Janet and David Polak Tumor and Vascular Biology Research Center and the Technion Integrated Cancer Center (TICC), The Rappaport Faculty of Medicine and Research Institute, Haifa, 31096 (Israel); Ziv, Tamar [The Smoler Proteomics Center, Faculty of Biology – Technion-Israel Institute of Technology, Haifa, 32000 (Israel); Braten, Ori [The Janet and David Polak Tumor and Vascular Biology Research Center and the Technion Integrated Cancer Center (TICC), The Rappaport Faculty of Medicine and Research Institute, Haifa, 31096 (Israel); Admon, Arie [The Smoler Proteomics Center, Faculty of Biology – Technion-Israel Institute of Technology, Haifa, 32000 (Israel); Udasin, Ronald G. [The Janet and David Polak Tumor and Vascular Biology Research Center and the Technion Integrated Cancer Center (TICC), The Rappaport Faculty of Medicine and Research Institute, Haifa, 31096 (Israel); Ciechanover, Aaron, E-mail: aaroncie@tx.technion.ac.il [The Janet and David Polak Tumor and Vascular Biology Research Center and the Technion Integrated Cancer Center (TICC), The Rappaport Faculty of Medicine and Research Institute, Haifa, 31096 (Israel)
2016-06-17
Several protein quality control systems in bacteria and/or mitochondrial matrix from lower eukaryotes are absent in higher eukaryotes. These are transfer-messenger RNA (tmRNA), The N-end rule ATP-dependent protease ClpAP, and two more ATP-dependent proteases, HslUV and ClpXP (in yeast). The lost proteases resemble the 26S proteasome and the role of tmRNA and the N-end rule in eukaryotic cytosol is performed by the ubiquitin proteasome system (UPS). Therefore, we hypothesized that the UPS might have substituted these systems – at least partially – in the mitochondrial matrix of higher eukaryotes. Using three independent experimental approaches, we demonstrated the presence of ubiquitinated proteins in the matrix of isolated yeast mitochondria. First, we show that isolated mitochondria contain ubiquitin (Ub) conjugates, which remained intact after trypsin digestion. Second, we demonstrate that the mitochondrial soluble fraction contains Ub-conjugates, several of which were identified by mass spectrometry and are localized to the matrix. Third, using immunoaffinity enrichment by specific antibodies recognizing digested ubiquitinated peptides, we identified a group of Ub-modified matrix proteins. The modification was further substantiated by separation on SDS-PAGE and immunoblots. Last, we attempted to identify the ubiquitin ligase(s) involved, and identified Dma1p as a trypsin-resistant protein in our mitochondrial preparations. Taken together, these data suggest a yet undefined role for the UPS in regulation of the mitochondrial matrix proteins. -- Highlights: •Mitochondrial matrix contains ubiquitinated proteins. •Ubiquitination occurs most probably in the matrix. •Dma1p is a ubiquitin ligase present in mitochondrial preparations.
Substitution among exhaustible resources and intergenerational equity
Energy Technology Data Exchange (ETDEWEB)
Hartwick, J.M.
1978-06-01
Hartwick (American Econ. Rev., 66 (Dec. 1977)) showed that implicit in R.M. Solow's model of intergenerational equity and exhaustible resources (Rev. Econ. Studies (Symposium, 1974) 29-46) was the savings-investment rule: society should invest in reproducible capital precisely the current returns from the use of flows of exhaustible resources in order to maintain per capita consumption constant. Population was assumed to remain constant. Solow and Hartwick assumed that there was only one exhaustible resource. Beckmann (American Econ. Rev., 65, 695-99 (Sept 1975)) investigated optimal growth in models with many exhaustible resources. In this paper the case of many exhaustible resources is considered and results are derived on substitution among resources and on the nature of paths of development. One of Beckmann's results on substitution is analyzed. The approach is first to analyze efficient paths under the assumption of general savings functions and then to analyze efficient paths under the assumption of the special savings function referred to above. Results indicate the Solow's existence theorem remains valid for the case of many exhaustible resources and some light is shed on the existence of paths for production functions not of the Cobb-Douglas form. 12 references.
Graben, Peter beim; Fröhlich, Flavio
2015-01-01
We optimally estimate the recurrence structure of a multivariate time series by Markov chains obtained from recurrence grammars. The goodness of fit is assessed with a utility function derived from the stochastic Markov transition matrix. It assumes a local maximum for the distance threshold of the optimal recurrence grammar. We validate our approach by means of the nonlinear Lorenz system and its linearized stochastic surrogates. Finally we apply our optimization procedure to the segmentation of neurophysiological time series obtained from anesthetized animals. We propose the number of optimal recurrence domains as a statistic for classifying an animals' state of consciousness.
Institute of Scientific and Technical Information of China (English)
Huanyin CHEN
2009-01-01
The necessary and sufficient conditions under which a ring satisfies regular power-substitution are investigated. It is shown that a ring R satisfies regular power-substitution if and only if a(-～)b in R implies that there exist n ∈ N and a U ∈ GLn(R) such that aU =Ub if and only if for any regular x ∈ R there exist m,n ∈ N and U ∈ GLn(R) such that xmIn = xmUxm, where a(-～)b means that there exists x, y, z ∈ R such that a = ybx, b = xaz and x = xyx = xzx. It is proved that every directly finite simple ring satisfies regular power-substitution. Some applications for stably free R-modules are also obtained.
40 CFR 721.10040 - Substituted acridine naphtha substituted benzamide (generic).
2010-07-01
... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted acridine naphtha... Significant New Uses for Specific Chemical Substances § 721.10040 Substituted acridine naphtha substituted... substance identified generically as a substituted acridine naphtha substituted benzamide (PMN P-02-522) is...
2010-07-01
... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Copper complex of (substituted... Copper complex of (substituted sulfonaphthyl azo substituted phenyl) disulfonaphthyl azo, amine salt... substances identified generically as copper complex of (substituted sulfonaphthyl azo substituted...
Substituted decision making: elder guardianship.
Leatherman, Martha E; Goethe, Katherine E
2009-11-01
The goal of this column is to help experienced clinicians navigate the judicial system when they are confronted with requests for capacity evaluations that involve guardianship (conservatorship). The interface between the growing elderly medical population and increasing requests for substituted decision making is becoming more complex. This column will help practicing psychiatrists understand the medical, legal, and societal factors involved in adult guardianship. Such understanding is necessary in order to effectively perform guardianship evaluations and adequately inform courts, patients, and families about the psychiatric diagnoses central to substituted decision making.
Hypoxic radiosensitizers: substituted styryl derivatives.
Nudelman, A; Falb, E; Odesa, Y; Shmueli-Broide, N
1994-10-01
A number of novel styryl epoxides, N-substituted-styryl-ethanolamines, N-mono and N,N'-bis-(2-hydroxyethyl)-cinnamamides--analogues to the known radiosensitizers RSU-1069, pimonidazole and etanidazole--display selective hypoxic radiosensitizing activity. The styryl group, especially when substituted by electron withdrawing groups, was found to be bioisosteric to the nitroimidazolyl functionality. The most active derivative 2-(2'-nitrophenyl)ethen-1-yl-oxirane 8a displayed a sensitizer enhancement ratio (SER) of 5 relative to misonidazole.
Designing robust sensing matrix for image compression.
Li, Gang; Li, Xiao; Li, Sheng; Bai, Huang; Jiang, Qianru; He, Xiongxiong
2015-12-01
This paper deals with designing sensing matrix for compressive sensing systems. Traditionally, the optimal sensing matrix is designed so that the Gram of the equivalent dictionary is as close as possible to a target Gram with small mutual coherence. A novel design strategy is proposed, in which, unlike the traditional approaches, the measure considers of mutual coherence behavior of the equivalent dictionary as well as sparse representation errors of the signals. The optimal sensing matrix is defined as the one that minimizes this measure and hence is expected to be more robust against sparse representation errors. A closed-form solution is derived for the optimal sensing matrix with a given target Gram. An alternating minimization-based algorithm is also proposed for addressing the same problem with the target Gram searched within a set of relaxed equiangular tight frame Grams. The experiments are carried out and the results show that the sensing matrix obtained using the proposed approach outperforms those existing ones using a fixed dictionary in terms of signal reconstruction accuracy for synthetic data and peak signal-to-noise ratio for real images.
Performance evaluation of matrix gradient coils.
Jia, Feng; Schultz, Gerrit; Testud, Frederik; Welz, Anna Masako; Weber, Hans; Littin, Sebastian; Yu, Huijun; Hennig, Jürgen; Zaitsev, Maxim
2016-02-01
In this paper, we present a new performance measure of a matrix coil (also known as multi-coil) from the perspective of efficient, local, non-linear encoding without explicitly considering target encoding fields. An optimization problem based on a joint optimization for the non-linear encoding fields is formulated. Based on the derived objective function, a figure of merit of a matrix coil is defined, which is a generalization of a previously known resistive figure of merit for traditional gradient coils. A cylindrical matrix coil design with a high number of elements is used to illustrate the proposed performance measure. The results are analyzed to reveal novel features of matrix coil designs, which allowed us to optimize coil parameters, such as number of coil elements. A comparison to a scaled, existing multi-coil is also provided to demonstrate the use of the proposed performance parameter. The assessment of a matrix gradient coil profits from using a single performance parameter that takes the local encoding performance of the coil into account in relation to the dissipated power.
Koopman, W.J.H.; Distelmaier, F.; Hink, M.A.; Verkaart, S.; Wijers, M.; Fransen, J.; Smeitink, J.A.M.; Willems, P.H.G.M.
2008-01-01
Mitochondria continuously change shape, position, and matrix configuration for optimal metabolite exchange. It is well established that changes in mitochondrial metabolism influence mitochondrial shape and matrix configuration. We demonstrated previously that inhibition of mitochondrial complex I (C
Hypercontractivity in finite-dimensional matrix algebras
Energy Technology Data Exchange (ETDEWEB)
Junge, Marius, E-mail: junge@math.uiuc.edu [Department of Mathematics, University of Illinois at Urbana-Champaign, 1409 W. Green St., Urbana, Illinois 61891 (United States); Palazuelos, Carlos, E-mail: carlospalazuelos@ucm.es [Instituto de Ciencias Matemáticas, CSIC-UAM-UC3M-UCM, Universidad Complutense de Madrid, Facultad de Ciencias Matemáticas, Plaza de Ciencias s/n, 28040 Madrid (Spain); Parcet, Javier, E-mail: javier.parcet@icmat.es; Perrin, Mathilde, E-mail: mathilde.perrin@icmat.es [Instituto de Ciencias Matemáticas, CSIC-UAM-UC3M-UCM, Consejo Superior de Investigaciones Científicas, C/ Nicolás Cabrera 13-15, 28049 Madrid (Spain)
2015-02-15
We obtain hypercontractivity estimates for a large class of semigroups defined on finite-dimensional matrix algebras M{sub n}. These semigroups arise from Poisson-like length functions ψ on ℤ{sub n} × ℤ{sub n} and provide new hypercontractive families of quantum channels when ψ is conditionally negative. We also study the optimality of our estimates.
Hierarchical matrix approximation of large covariance matrices
Litvinenko, Alexander
2015-11-30
We approximate large non-structured Matérn covariance matrices of size n×n in the H-matrix format with a log-linear computational cost and storage O(kn log n), where rank k ≪ n is a small integer. Applications are: spatial statistics, machine learning and image analysis, kriging and optimal design.
Pesticide Substitution: Combining Food Safety with Environmental Quality
DEFF Research Database (Denmark)
Fantke, Peter
2015-01-01
Various pesticides are authorized for use on agricultural food crops. Despite regulatory risk assessments aiming at ensuring consumer and environmental safety, pesticides contribute to human and environmental impacts. Guidance is needed to optimize pesticide use practice and minimize human......% by defining adequate substitution scenarios. Comprehensive scenarios need to also consider worker and environmental burden, and information on crop rotation, pest pressure, environmental conditions, application costs and efficacy. Such scenarios help to increase food safety and more sustainable use...
Documentation of capacity and identification of substitute decisionmakers in Ontario.
Foreman, Thomas C; Curran, Dorothyann; Landry, Joshua T; Kekewich, Michael A
2014-07-01
Documenting capacity assessments and identifying substitute decisionmakers (SDMs) in healthcare facilities is ethically required for optimal patient care. Lack of such documentation has the potential to generate confusion and contention among patients, their family members, and members of the healthcare team. An overview of our research at the Ottawa Hospital and issues that influence the consistency of documentation in the Canadian context are presented here, as well as ideas for the mitigation of these issues and ways to encourage better documentation.
Tax Rates as Strategic Substitutes
R.A. de Mooij (Ruud); H. Vrijburg (Hendrik)
2012-01-01
textabstractThis paper analytically derives the conditions under which the slope of the tax reaction function is negative in a classical tax competition model. If countries maximize welfare, we show that a negative slope (reflecting strategic substitutability) occurs under relatively mild conditions
Tax rates as strategic substitutes
H. Vrijburg (Hendrik); R.A. de Mooij (Ruud)
2016-01-01
textabstractThis paper analytically derives conditions under which the slope of the tax-reaction function is negative in a classical tax competition model. If countries maximize welfare, a negative slope (reflecting strategic substitutability) occurs under relatively mild conditions. The strategic t
Tax rates as strategic substitutes
H. Vrijburg (Hendrik); R.A. de Mooij (Ruud)
2016-01-01
textabstractThis paper analytically derives conditions under which the slope of the tax-reaction function is negative in a classical tax competition model. If countries maximize welfare, a negative slope (reflecting strategic substitutability) occurs under relatively mild conditions. The strategic t
No Substitute Teacher Left behind
O'Connor, Kevin
2009-01-01
Schools and districts routinely recruit, retain, and support highly qualified teachers to ensure that students receive the best learning opportunities. However, even if one's school employs highly qualified full-time teachers, it is important to acknowledge that substitute teachers also have a significant impact on the education of students. One…
Parallelism in matrix computations
Gallopoulos, Efstratios; Sameh, Ahmed H
2016-01-01
This book is primarily intended as a research monograph that could also be used in graduate courses for the design of parallel algorithms in matrix computations. It assumes general but not extensive knowledge of numerical linear algebra, parallel architectures, and parallel programming paradigms. The book consists of four parts: (I) Basics; (II) Dense and Special Matrix Computations; (III) Sparse Matrix Computations; and (IV) Matrix functions and characteristics. Part I deals with parallel programming paradigms and fundamental kernels, including reordering schemes for sparse matrices. Part II is devoted to dense matrix computations such as parallel algorithms for solving linear systems, linear least squares, the symmetric algebraic eigenvalue problem, and the singular-value decomposition. It also deals with the development of parallel algorithms for special linear systems such as banded ,Vandermonde ,Toeplitz ,and block Toeplitz systems. Part III addresses sparse matrix computations: (a) the development of pa...
Effect of the substitution of f-electron elements on the structure and elastic properties of UO2
Behera, Rakesh K.; Deo, Chaitanya S.; Xu, Haixuan
2013-02-01
The chemistry of nuclear reactor fuel initially is complex, and continuous loss of uranium and plutonium, and formation of a broad range of new species due to fission introduce a challenging time-dependence to this chemistry. Lanthanides and/or Actinides substitution on the uranium sublattice occurs (a) during fission, (b) when mixed oxide fuel is used, and (c) when minor Actinides are reprocessed in UO2 matrix fuel as part of a closed nuclear fuel cycle. These fission products and minor Actinides influence a variety of thermo-physical properties, which depend on structure and elastic properties. How these structural and elastic properties vary with Lanthanide and Actinide substitution is not well studied. In this study we use atomic level simulations to investigate the effect of 4+ and 3+ ion substitutions on the structural and elastic properties of urania matrix. Our results show that most of the 4+ ions reduce the overall lattice parameter, while all the 3+ ions considered here increased the lattice parameter of the urania matrix. This effect is guided by the interplay between the elastic and electrostatic effect of the substituted ions. We calculate the chemical expansion and chemical expansion coefficient with the change in concentration based on the ionic radii of the substituted 3+ and 4+ ions. In general, elastic properties are enhanced for 4+ ions substitution and reduced for 3+ ion substitution.
Institute of Scientific and Technical Information of China (English)
无
2003-01-01
Matrix-bound phosphine was determined in the Jiaozhou Bay coastal sediment, in prawn-pond bottom soil, in the eutrophic lake Wulongtan, in the sewage sludge and in paddy soil as well. Results showed that matrix-bound phosphine levels in freshwater and coastal sediment, as well as in sewage sludge, are significantly higher than that in paddy soil. The correlation between matrix bound phosphine concentrations and organic phosphorus contents in sediment samples is discussed.
Al-Tufail, M; Akram, M; Haq, A
1999-03-01
The method previously used in the Toxicology Laboratories of King Faisal Specialist Hospital and Research Center for determining the zinc concentration in serum by Zeeman atomic absorption spectrometer was improved by modifying the matrix modifier and by changing the heated graphite furnace atomization (HGA) program. After trying several methods we failed to achieve the required precision and the accuracy of methods for serum zinc determination. We changed the matrix modifier to a fifty percent mixture (v/v) of 3.90 grams per liter of ammonium phosphate in Type 1 water with 0.2% nitric acid and 1.0 gram per liter of magnesium nitrate in acidic water (0.2% HNO3) with 0.1% triton X-100 was used as matrix modifier. A twenty-five fold dilution of the sample in matrix modifier was injected on the L'vov's platform of the furnace. In order to reduce the high sensitivity of Zn the furnace program was modified. The method is found very robust. The average reproducibility between inter-runs and intra-run is less than 1.59% with a high degree of accuracy. We used two levels of controls i.e. normal or low level and abnormal or high level. The linearity and the detection limit of the assay were 0.9992 and 0.010 micromol/L respectively. Average recovery of the analyte was 98.65%. The X-Bar and R charts were constructed by using Shewhart's statistical analysis technique to assess the test methodology. It was found that the assay is capable and stable for routine clinical and research analysis. The capability index (C(P)) of the assay, an indicator of the precision, was calculated.
Decellularized bone matrix grafts for calvaria regeneration
Lee, Dong Joon; Diachina, Shannon; Lee, Yan Ting; Zhao, Lixing; Zou, Rui; Tang, Na; Han, Han; Chen, Xin; Ko, Ching-Chang
2016-01-01
Decellularization is a promising new method to prepare natural matrices for tissue regeneration. Successful decellularization has been reported using various tissues including skin, tendon, and cartilage, though studies using hard tissue such as bone are lacking. In this study, we aimed to define the optimal experimental parameters to decellularize natural bone matrix using 0.5% sodium dodecyl sulfate and 0.1% NH4OH. Then, the effects of decellularized bone matrix on rat mesenchymal stem cell proliferation, osteogenic gene expression, and osteogenic differentiations in a two-dimensional culture system were investigated. Decellularized bone was also evaluated with regard to cytotoxicity, biochemical, and mechanical characteristics in vitro. Evidence of complete decellularization was shown through hematoxylin and eosin staining and DNA measurements. Decellularized bone matrix displayed a cytocompatible property, conserved structure, mechanical strength, and mineral content comparable to natural bone. To study new bone formation, implantation of decellularized bone matrix particles seeded with rat mesenchymal stem cells was conducted using an orthotopic in vivo model. After 3 months post-implantation into a critical-sized defect in rat calvaria, new bone was formed around decellularized bone matrix particles and also merged with new bone between decellularized bone matrix particles. New bone formation was analyzed with micro computed tomography, mineral apposition rate, and histomorphometry. Decellularized bone matrix stimulated mesenchymal stem cell proliferation and osteogenic differentiation in vitro and in vivo, achieving effective bone regeneration and thereby serving as a promising biological bone graft. PMID:28228929
Decellularized bone matrix grafts for calvaria regeneration
Directory of Open Access Journals (Sweden)
Dong Joon Lee
2016-12-01
Full Text Available Decellularization is a promising new method to prepare natural matrices for tissue regeneration. Successful decellularization has been reported using various tissues including skin, tendon, and cartilage, though studies using hard tissue such as bone are lacking. In this study, we aimed to define the optimal experimental parameters to decellularize natural bone matrix using 0.5% sodium dodecyl sulfate and 0.1% NH4OH. Then, the effects of decellularized bone matrix on rat mesenchymal stem cell proliferation, osteogenic gene expression, and osteogenic differentiations in a two-dimensional culture system were investigated. Decellularized bone was also evaluated with regard to cytotoxicity, biochemical, and mechanical characteristics in vitro. Evidence of complete decellularization was shown through hematoxylin and eosin staining and DNA measurements. Decellularized bone matrix displayed a cytocompatible property, conserved structure, mechanical strength, and mineral content comparable to natural bone. To study new bone formation, implantation of decellularized bone matrix particles seeded with rat mesenchymal stem cells was conducted using an orthotopic in vivo model. After 3 months post-implantation into a critical-sized defect in rat calvaria, new bone was formed around decellularized bone matrix particles and also merged with new bone between decellularized bone matrix particles. New bone formation was analyzed with micro computed tomography, mineral apposition rate, and histomorphometry. Decellularized bone matrix stimulated mesenchymal stem cell proliferation and osteogenic differentiation in vitro and in vivo, achieving effective bone regeneration and thereby serving as a promising biological bone graft.
Zhukauskas, Rasa; Dodds, Robert A; Hartill, Caroline; Arola, Travis; Cobb, Ronald R; Fox, Casey
2010-03-01
Complex fractures resulting in bone loss or impaired fracture healing remain problematic in trauma and orthopedic surgeries. Many bone graft substitutes have been developed and are commercially available. These products differ in their osteoconductive and osteoinductive properties. Differential enhancement of these properties may optimize the performance of these products for various orthopedic and craniofacial applications. The use of bone graft substitutes offers the ability to lessen the possible morbidity of the harvest site in autografts. The objective of the present study was to compare the ability of two bone graft substitutes, BioSet RT, an allograft demineralized bone matrix formulation, and ProOsteon 500R, a coralline hydroxyapatite, in a rabbit critical tibial defect model. BioSet RT and ProOsteon 500R were implanted into a unicortical proximal metaphyseal tibial defect and evaluated for new bone formation. Samples were analyzed radiographically and histologically at 1 day, 6 weeks, 12 weeks, and 24 weeks post surgery. Both materials were biocompatible and demonstrated significant bone growth and remodeling. At 12 weeks, the BioSet RT implanted sites demonstrated significantly more defect closure and bone remodeling as determined by radiographic analyses with 10 out of 14 defects being completely healed versus 1 out of 14 being completely healed in the ProOsteon 500R implanted sites. At 24 weeks, both materials demonstrated complete closure of the defect as determined histologically. There were no statistical differences in radiographic scores between the two implanted materials. However, there was an observable trend that the BioSet RT material generated higher histological and radiographic scores, although not statistically significant. This study provides evidence that both BioSet RT and ProOsteon 500R are biocompatible and able to induce new bone formation as measured in this rabbit model. In addition, this in vivo study demonstrates the ability of
Approaches in Substitution of Organic Solvents
DEFF Research Database (Denmark)
Jacobsen, Thomas
2000-01-01
In substitution of harmful chemicals or products with less harmful or harmless ones, there are different approaches according to the different situations, the technical requirements to the substitutes, and the goals for the substitution. Three different cases are presented. The substitution process...... may be characterized by two phases, the invention phase and the implementation phase. Different qualifications are needed in the two phases, but a thorough knowledge of the production process in question is necessary in both....
Seraji, H.
1987-01-01
Given a multivariable system, it is proved that the numerator matrix N(s) of the transfer function evaluated at any system pole either has unity rank or is a null matrix. It is also shown that N(s) evaluated at any transmission zero of the system has rank deficiency. Examples are given for illustration.
Smart Phones and their Substitutes
DEFF Research Database (Denmark)
Bødker, Mads; Gimpel, Gregory; Hedman, Jonas
2009-01-01
Drawing on data from a longitudinal field study, this paper investigates the influence of existing, better and stand-alone technology substitutes on the use of smart phones. By applying prospect theory, media richness theory, and business model literature, the purpose of this paper is to improve...... our understanding of the role of substitutes, device content fit issues, and implications for business models by asking the question: What is an effective business model to address the relationship between user preference and the fit of the smart phone and everyday task? The field study data suggest...... the need for business models to recognize that adoption decisions are reference-dependent and strongly influenced by the fit between task and smart phone....
40 CFR 721.323 - Substituted acrylamide.
2010-07-01
... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted acrylamide. 721.323... Substances § 721.323 Substituted acrylamide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance generically identified as substituted acrylamide (PMN P-90-1687) is...
24 CFR 220.253 - Substitute mortgagors.
2010-04-01
... Contract Rights and Obligations-Homes § 220.253 Substitute mortgagors. (a) Selling mortgagor. The mortgagee... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Substitute mortgagors. 220.253... the Commissioner's approval of a substitute mortgagor, as provided by this section. (b)...
24 CFR 221.252 - Substitute mortgagors.
2010-04-01
... Cost Homes § 221.252 Substitute mortgagors. (a) Selling mortgagor. The mortgagee may effect the release... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Substitute mortgagors. 221.252... approval of a substitute mortgagor, as provided by this section. (b) Purchasing mortgagor. The...
40 CFR 721.5867 - Substituted phenol.
2010-07-01
... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted phenol. 721.5867 Section... Substances § 721.5867 Substituted phenol. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance generically identified as substituted phenol (PMNs P-89-1125,...
Substituted Indoleacetic Acids Tested in Tissue Cultures
DEFF Research Database (Denmark)
Engvild, Kjeld Christensen
1978-01-01
Monochloro substituted IAA inhibited shoot induction in tobacco tissue cultures about as much as IAA. Dichloro substituted IAA inhibited shoot formation less. Other substituted IAA except 5-fluoro- and 5-bromoindole-3-acetic acid were less active than IAA. Callus growth was quite variable...
40 CFR 721.9820 - Substituted triazole.
2010-07-01
... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted triazole. 721.9820 Section... Substances § 721.9820 Substituted triazole. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance generically identified as a substituted triazole (PMN P-90-1731)...
Substitution reactions at boron atoms in metallacarboranes
Energy Technology Data Exchange (ETDEWEB)
Bregadze, Vladimir I; Timofeev, Sergei V; Sivaev, Igor B; Lobanova, Irina A [A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow (Russian Federation)
2004-05-31
Data on substitution reactions at boron atoms in 10-12-vertex metallacarboranes, which are of fundamental and applied significance, are generalised. The possible mechanisms of substitution reactions and the influence of the metal fragment on substitution positions in the polyhedron are discussed.
40 CFR 721.8775 - Substituted pyridines.
2010-07-01
... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted pyridines. 721.8775... Substances § 721.8775 Substituted pyridines. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified generically as substituted pyridine (PMN P-84-1219)...
Iridium-Catalyzed Allylic Substitution
Hartwig, John F.; Pouy, Mark J.
Iridium-catalyzed asymmetric allylic substitution has become a valuable method to prepare products from the addition of nucleophiles at the more substituted carbon of an allyl unit. The most active and selective catalysts contain a phosphoramidite ligand possessing at least one arylethyl substituent on the nitrogen atom of the ligand. In these systems, the active catalyst is generated by a base-induced cyclometalation at the methyl group of this substituent to generate an iridium metalacycle bound by the COD ligand of the [Ir(COD)Cl]2 precursor and one additional labile dative ligand. Such complexes catalyze the reactions of linear allylic esters with alkylamines, arylamines, phenols, alcohols, imides, carbamates, ammonia, enolates and enolate equivalents, as well as typical stabilized carbon nucleophiles generated from malonates and cyanoesters. Iridium catalysts for enantioselective allylic substitution have also been generated from phosphorus ligands with substituents bound by heteroatoms, and an account of the studies of such systems, along with a description of the development of iridium catalysts is included.
Optimally Stopped Optimization
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.
Optimization and Optimal Control
Chinchuluun, Altannar; Enkhbat, Rentsen; Tseveendorj, Ider
2010-01-01
During the last four decades there has been a remarkable development in optimization and optimal control. Due to its wide variety of applications, many scientists and researchers have paid attention to fields of optimization and optimal control. A huge number of new theoretical, algorithmic, and computational results have been observed in the last few years. This book gives the latest advances, and due to the rapid development of these fields, there are no other recent publications on the same topics. Key features: Provides a collection of selected contributions giving a state-of-the-art accou
40 CFR 721.1555 - Substituted phenyl azo substituted benzenediazonium salt.
2010-07-01
... benzenediazonium salt. 721.1555 Section 721.1555 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.1555 Substituted phenyl azo substituted benzenediazonium salt. (a... generically as a substituted phenyl azo substituted benzenediazonium salt (PMN P-92-652) is subject to...
Directory of Open Access Journals (Sweden)
Zimmermann Karel
2010-01-01
Full Text Available Abstract Background Sequence comparisons make use of a one-letter representation for amino acids, the necessary quantitative information being supplied by the substitution matrices. This paper deals with the problem of finding a representation that provides a comprehensive description of amino acid intrinsic properties consistent with the substitution matrices. Results We present a Euclidian vector representation of the amino acids, obtained by the singular value decomposition of the substitution matrices. The substitution matrix entries correspond to the dot product of amino acid vectors. We apply this vector encoding to the study of the relative importance of various amino acid physicochemical properties upon the substitution matrices. We also characterize and compare the PAM and BLOSUM series substitution matrices. Conclusions This vector encoding introduces a Euclidian metric in the amino acid space, consistent with substitution matrices. Such a numerical description of the amino acid is useful when intrinsic properties of amino acids are necessary, for instance, building sequence profiles or finding consensus sequences, using machine learning algorithms such as Support Vector Machine and Neural Networks algorithms.
Hydroxyl radical substitution in halogenated carbonyls: oxalic acid formation.
Christiansen, Carrie J; Dalal, Shakeel S; Francisco, Joseph S; Mebel, Alexander M; Gaffney, Jeffrey S
2010-03-04
An ab initio study of OH radical substitution reactions in halogenated carbonyls is conducted. Hydroxyl radical substitution into oxalyl dichloride [ClC(O)C(O)Cl] and oxalyl dibromide [BrC(O)C(O)Br], resulting in the formation of oxalic acid, is presented. Analogous substitution reactions in formyl chloride [ClCH(O)], acetyl chloride [ClC(O)CH(3)], formyl bromide [BrCH(O)], and acetyl bromide [BrC(O)CH(3)] are considered. Energetics of competing hydrogen abstraction reactions for all applicable species are computed for comparison. Geometry optimizations and frequency computations are performed using the second-order Møller-Plesset perturbation theory (MP2) and the 6-31G(d) basis set for all minimum species and transition states. Single point energy computations are performed using fourth-order Møller-Plesset perturbation theory (MP4) and coupled cluster theory [CCSD(T)]. Potential energy surfaces, including activation energies and enthalpies, are determined from the computations. These potential energy surfaces show that OH substitution into ClC(O)C(O)Cl and BrC(O)C(O)Br, resulting in the formation of oxalic acid and other minor products, is energetically favorable. Energetics of analogous reactions with ClCH(O), BrCH(O), ClC(O)CH(3), and BrC(O)CH(3) are also computed.
[First year of life. Human milk and human milk substitutes].
Vásquez-Garibay, Edgar M
2016-09-01
The nutritional improvement of mothers and their children is one of the most cost-effective tools to achieve optimal human growth and development. The World Health Organization recommends offering «exclusive breastfeeding for the first six months, and then begin the introduction of safe and nutritious food while breastfeeding continues until the second year of life.» Since the second half of the 20th century to date extraordinary progress in the manufacturing and formulation of substitutes for human milk has been accomplished, these being partial or complete substitutes for human milk, whether or not suitable for this purpose. Whole (cow´s) milk is not an adequate substitute for human milk during the first six months of life because of its great nutritional disparity and excess solutes with potential deleterious effects in infants. Therefore, it is an ethical responsibility of health professional to educate and advise parents and caregivers on the proper and timely use of human milk substitutes available in our country.
Optimization of a Strontium Aluminate
Energy Technology Data Exchange (ETDEWEB)
Bone, Alexandria N. [Maryville College, TN (United States)
2017-08-01
Strontium aluminate with Eu^{2+} and Dy^{3+} has been at the forefront of emerging applications for storage phosphors since its discovery in 1996. In this study, the emission intensity and luminescence lifetime of SrAl_{2}O_{4}: Eu^{2+}, Dy^{3+} were enhanced by partial substitution of Ca^{2+} into Sr^{2+} sites in the matrix.
Improved Matrix Uncertainty Selector
Rosenbaum, Mathieu
2011-01-01
We consider the regression model with observation error in the design: y=X\\theta* + e, Z=X+N. Here the random vector y in R^n and the random n*p matrix Z are observed, the n*p matrix X is unknown, N is an n*p random noise matrix, e in R^n is a random noise vector, and \\theta* is a vector of unknown parameters to be estimated. We consider the setting where the dimension p can be much larger than the sample size n and \\theta* is sparse. Because of the presence of the noise matrix N, the commonly used Lasso and Dantzig selector are unstable. An alternative procedure called the Matrix Uncertainty (MU) selector has been proposed in Rosenbaum and Tsybakov (2010) in order to account for the noise. The properties of the MU selector have been studied in Rosenbaum and Tsybakov (2010) for sparse \\theta* under the assumption that the noise matrix N is deterministic and its values are small. In this paper, we propose a modification of the MU selector when N is a random matrix with zero-mean entries having the variances th...
Bansal, Shruti; Soni, Sanjeev Kumar; Harjai, Kusum; Chhibber, Sanjay
2014-07-01
Formation of dense, highly hydrated biofilm structures pose a risk for public and environmental health. Extracellular polymeric substances encompassing biofilms offer 1000-fold greater resistance as compared to the planktonic cells. Using enzymes as anti-biofouling agents, will improve penetration of antimicrobials and increase susceptibility of biofilms to components of immune system. The challenge of using enzymes derived from unrelated bacteria for the degradation of capsular matrix of Klebsiella pneumoniae has not been dealt in the past. Thus, statistical optimization was done to enhance depolymerase production by Aeromonas punctata, directed against the exopolysaccharide matrix of Klebsiella pneumoniae B5055, capable of substituting the available phage borne depolymerase enzyme. Optimization via central composite design (CCD) resulted in 16-fold enhancement in depolymerase yield (166.65 µmoles ml(-1) min(-1) ) over unoptimized medium. Out of the 19 variables, media composition giving maximum expression levels of the enzyme consisted of 1 mg ml(-1) galactose and ammonium chloride, 1.5 mg ml(-1) each of capsular polysaccharide (CPS) and magnesium sulfate. Tryptic peptide analysis of the purified 29 kDa band by Matrix assisted laser desorption ionization-time of flight (MALDI-TOF) showed a high homology with a protein of unknown function from Aeromonas cavaie Ae398. Further improvements in the enzyme can lead to its successful development as prophylactic and/or a therapeutic agent.
Eves, Howard
1980-01-01
The usefulness of matrix theory as a tool in disciplines ranging from quantum mechanics to psychometrics is widely recognized, and courses in matrix theory are increasingly a standard part of the undergraduate curriculum.This outstanding text offers an unusual introduction to matrix theory at the undergraduate level. Unlike most texts dealing with the topic, which tend to remain on an abstract level, Dr. Eves' book employs a concrete elementary approach, avoiding abstraction until the final chapter. This practical method renders the text especially accessible to students of physics, engineeri
Rheocasting Al matrix composites
Energy Technology Data Exchange (ETDEWEB)
Girot, F.A.; Albingre, L.; Quenisset, J.M.; Naslain, R.
1987-11-01
A development status account is given for the rheocasting method of Al-alloy matrix/SiC-whisker composites, which involves the incorporation and homogeneous distribution of 8-15 vol pct of whiskers through the stirring of the semisolid matrix melt while retaining sufficient fluidity for casting. Both 1-, 3-, and 6-mm fibers of Nicalon SiC and and SiC whisker reinforcements have been experimentally investigated, with attention to the characterization of the resulting microstructures and the effects of fiber-matrix interactions. A thin silica layer is found at the whisker surface. 7 references.
Mueller matrix differential decomposition.
Ortega-Quijano, Noé; Arce-Diego, José Luis
2011-05-15
We present a Mueller matrix decomposition based on the differential formulation of the Mueller calculus. The differential Mueller matrix is obtained from the macroscopic matrix through an eigenanalysis. It is subsequently resolved into the complete set of 16 differential matrices that correspond to the basic types of optical behavior for depolarizing anisotropic media. The method is successfully applied to the polarimetric analysis of several samples. The differential parameters enable one to perform an exhaustive characterization of anisotropy and depolarization. This decomposition is particularly appropriate for studying media in which several polarization effects take place simultaneously. © 2011 Optical Society of America
Energy Technology Data Exchange (ETDEWEB)
Zhang, Shengnan, E-mail: snzhang@c-nin.com [Superconducting Materials Research Center, Northwest Institute for Nonferrous Metal Research, Xi’an 710016 (China); Li, Chengshan; Hao, Qingbin [Superconducting Materials Research Center, Northwest Institute for Nonferrous Metal Research, Xi’an 710016 (China); Lu, Tianni [Superconducting Materials Research Center, Northwest Institute for Nonferrous Metal Research, Xi’an 710016 (China); College of Materials Science and Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); Zhang, Pingxiang [Superconducting Materials Research Center, Northwest Institute for Nonferrous Metal Research, Xi’an 710016 (China)
2015-04-15
Highlights: • Optimization of intergrain connections has been obtained by Yb doping. • Changes of the grain boundary structures after doping have been observed by HRTEM. • Flux pinning mechanism change with Yb doping has been analyzed and explained. • Improved critical current density has been obtained by proper amount of Yb doping. - Abstract: Polycrystalline bulks Bi{sub 2}Sr{sub 2−x}Yb{sub x}CaCu{sub 2.0}O{sub 8+δ} (Bi-2212) with Yb doping content of x = 0, 0.01, 0.02 and 0.05) were fabricated by solid state sintering process. Bi-2212 precursor powders were synthesized by modified co-precipitation process, and Yb{sub 2}O{sub 3} powders were added into the precursor powders during the calcination process as dopants. The influences of Yb substitution on the lattice parameter, microstructure and related superconducting properties were systematically investigated. The amorphous components within the grain boundaries were observed with HRTEM, which contributed to the formation of weak links. Therefore, both the decreasing number of porosity and better crystallized grain boundary structure after Yb doping obviously enhanced the intergrain connections. Meanwhile, doping of Yb ions into Bi-2212 matrix also contributed to the enhancement of point pining, thus lead to the improvement of in-field critical current density. Based on the enhancements of both intergrain connections and flux pinning properties, improvement of critical current density was obtained with the optimal doping content of x = 0.02.
Institute of Scientific and Technical Information of China (English)
马永忠; 林金保; 吴烽华; 王超; 崔小朝
2013-01-01
Based on ANSYS optimization design basic theory,used ANSYS software for simulation analysis,the paper made structure optimization design for the support plate of Ti3SiC2/Al2O3 ceramic matrix composites,and finally got the mine support plate which met the required strength,easy molding and low cost.The paper also provides the basis for the optimization design of support plate in engineering.%本文以ANSYS优化设计基本理论为基础,以ANSYS为模拟分析软件,通过对Ti3SiC2/A12O3陶瓷基复合材料支护托板进行结构优化设计,最终得到满足强度要求、容易成型、且成本较低的矿用支护托板.为工程上的支护托板的优化设计提供了依据.
Directory of Open Access Journals (Sweden)
Ruisong Ye
2014-03-01
Full Text Available A secure image encryption scheme based on 2D skew tent map is proposed for the encryption of color images. The proposed encryption scheme is composed of one permutation process and one substitution process. The 3D color plain-image matrix is converted to 2D image matrix first, then 2D skew tent map is utilized to generate chaotic sequences, which are used for both permutation process and substitution process. The chaotic sequence for permutation process is dependent on plain-image and cipher keys, resulting in good key sensitivity and plaintext sensitivity. The substitution process is first initiated with the initial vectors generated by the cipher keys and 2D skew tent map, then the gray values of row and column pixels of 2D image matrix are mixed with the pseudorandom number sequences via bitxoring operation. Both permutation process and substitution process are executed row-by-row and column-by-column instead of pixel-by-pixel to improve the speed of encryption. The security and performance of the proposed image encryption have been analyzed, including histograms, correlation coefficients, information entropy, key sensitivity analysis, key space analysis, differential analysis, encryption/decryption rate analysis etc. All the experimental results suggest that the proposed image encryption scheme is robust and secure and can be used for secure image and video communication applications.
Heterogeneous Highly Parallel Implementation of Matrix Exponentiation Using GPU
Raja, Chittampally Vasanth; Raghavendra, Prakash S; 10.5121/ijdps.2012.3209
2012-01-01
The vision of super computer at every desk can be realized by powerful and highly parallel CPUs or GPUs or APUs. Graphics processors once specialized for the graphics applications only, are now used for the highly computational intensive general purpose applications. Very expensive GFLOPs and TFLOP performance has become very cheap with the GPGPUs. Current work focuses mainly on the highly parallel implementation of Matrix Exponentiation. Matrix Exponentiation is widely used in many areas of scientific community ranging from highly critical flight, CAD simulations to financial, statistical applications. Proposed solution for Matrix Exponentiation uses OpenCL for exploiting the hyper parallelism offered by the many core GPGPUs. It employs many general GPU optimizations and architectural specific optimizations. This experimentation covers the optimizations targeted specific to the Scientific Graphics cards (Tesla-C2050). Heterogeneous Highly Parallel Matrix Exponentiation method has been tested for matrices of ...
The "Pesticide-exposure Matrix" was developed to help epidemiologists and other researchers identify the active ingredients to which people were likely exposed when their homes and gardens were treated for pests in past years.
Koehler, Wolfgang
2011-01-01
A new classical theory of gravitation within the framework of general relativity is presented. It is based on a matrix formulation of four-dimensional Riemann-spaces and uses no artificial fields or adjustable parameters. The geometrical stress-energy tensor is derived from a matrix-trace Lagrangian, which is not equivalent to the curvature scalar R. To enable a direct comparison with the Einstein-theory a tetrad formalism is utilized, which shows similarities to teleparallel gravitation theories, but uses complex tetrads. Matrix theory might solve a 27-year-old, fundamental problem of those theories (sec. 4.1). For the standard test cases (PPN scheme, Schwarzschild-solution) no differences to the Einstein-theory are found. However, the matrix theory exhibits novel, interesting vacuum solutions.
DEFF Research Database (Denmark)
Schneider, Jesper Wiborg; Borlund, Pia
2007-01-01
The present two-part article introduces matrix comparison as a formal means for evaluation purposes in informetric studies such as cocitation analysis. In the first part, the motivation behind introducing matrix comparison to informetric studies, as well as two important issues influencing...... such comparisons, matrix generation, and the composition of proximity measures, are introduced and discussed. In this second part, the authors introduce and thoroughly demonstrate two related matrix comparison techniques the Mantel test and Procrustes analysis, respectively. These techniques can compare...... important. Alternatively, or as a supplement, Procrustes analysis compares the actual ordination results without investigating the underlying proximity measures, by matching two configurations of the same objects in a multidimensional space. An advantage of the Procrustes analysis though, is the graphical...
The Matrix Organization Revisited
DEFF Research Database (Denmark)
Gattiker, Urs E.; Ulhøi, John Parm
1999-01-01
This paper gives a short overview of matrix structure and technology management. It outlines some of the characteristics and also points out that many organizations may actualy be hybrids (i.e. mix several ways of organizing to allocate resorces effectively).......This paper gives a short overview of matrix structure and technology management. It outlines some of the characteristics and also points out that many organizations may actualy be hybrids (i.e. mix several ways of organizing to allocate resorces effectively)....
Optical Coherency Matrix Tomography
2015-10-19
optics has been studied theoretically11, but has not been demonstrated experimentally heretofore. Even in the simplest case of two binary DoFs6 (e.g...coherency matrix G spanning these DoFs. This optical coherency matrix has not been measured in its entirety to date—even in the simplest case of two...dense coding, etc. CREOL, The College of Optics & Photonics, University of Central Florida, Orlando , Florida 32816, USA. Correspondence and requests
Tenreiro Machado, J. A.
2015-08-01
This paper addresses the matrix representation of dynamical systems in the perspective of fractional calculus. Fractional elements and fractional systems are interpreted under the light of the classical Cole-Cole, Davidson-Cole, and Havriliak-Negami heuristic models. Numerical simulations for an electrical circuit enlighten the results for matrix based models and high fractional orders. The conclusions clarify the distinction between fractional elements and fractional systems.
Czerwinski, Michael; Spence, Jason R
2017-01-05
Recently in Nature, Gjorevski et al. (2016) describe a fully defined synthetic hydrogel that mimics the extracellular matrix to support in vitro growth of intestinal stem cells and organoids. The hydrogel allows exquisite control over the chemical and physical in vitro niche and enables identification of regulatory properties of the matrix. Copyright © 2017 Elsevier Inc. All rights reserved.
The Matrix Organization Revisited
DEFF Research Database (Denmark)
Gattiker, Urs E.; Ulhøi, John Parm
1999-01-01
This paper gives a short overview of matrix structure and technology management. It outlines some of the characteristics and also points out that many organizations may actualy be hybrids (i.e. mix several ways of organizing to allocate resorces effectively).......This paper gives a short overview of matrix structure and technology management. It outlines some of the characteristics and also points out that many organizations may actualy be hybrids (i.e. mix several ways of organizing to allocate resorces effectively)....
Studies of fiber-matrix debonding
Institute of Scientific and Technical Information of China (English)
Navneet DRONAMRAJU; Johannes SOLASS; Jorg HILDEBRAND
2015-01-01
In this paper, the debonding of a single fiber-matrix system of carbon fiber reinforced composite （12FRP） AS4/Epson 828 material is studied using Cohesive Zone Model （CZM）. The effect of parameters namely, maximum tangential contact stress, tangential slip distance and artificial damping coefficient on the debonding length at the interface of the fiber-matrix is analyzed. Contact elements used in the CZM are coupled based on a bilinear stress-strain curve. Load is applied on the matrix, tangential to the interface. Hence, debonding is observed primarily in Mode II. Wide range of values are considered to study the inter-dependency of the parameters and its effect on debonding length. Out of the three parameters mentioned, artificial damping coefficient and tangential slip distance significantly affect debonding length. A thorough investigation is recommended for case wise interface debonding analysis, to estimate the optimal parametric values while using CZM.
Wang, Gang; Chen, Changzheng; Yu, Shenbo
2016-09-01
In this paper, the static output-feedback control problem of active suspension systems with information structure constraints is investigated. In order to simultaneously improve the ride comfort and stability, a half car model is used. Other constraints such as suspension deflection, actuator saturation, and controller constrained information are also considered. A novel static output-feedback design method based on the variable substitution is employed in the controller design. A single-step linear matrix inequality (LMI) optimization problem is solved to derive the initial feasible solution with a sparsity constraint. The initial infeasibility issue of the static output-feedback is resolved by using state-feedback information. Specifically, an optimization algorithm is proposed to search for less conservative results based on the feasible controller gain matrix. Finally, the validity of the designed controller for different road profiles is illustrated through numerical examples. The simulation results indicate that the optimized static output-feedback controller can achieve better suspension performances when compared with the feasible static output-feedback controller.
Cement from magnesium substituted hydroxyapatite.
Lilley, K J; Gbureck, U; Knowles, J C; Farrar, D F; Barralet, J E
2005-05-01
Brushite cement may be used as a bone graft material and is more soluble than apatite in physiological conditions. Consequently it is considerably more resorbable in vivo than apatite forming cements. Brushite cement formation has previously been reported by our group following the mixture of nanocrystalline hydroxyapatite and phosphoric acid. In this study, brushite cement was formed from the reaction of nanocrystalline magnesium-substituted hydroxyapatite with phosphoric acid in an attempt to produce a magnesium substituted brushite cement. The presence of magnesium was shown to have a strong effect on cement composition and strength. Additionally the presence of magnesium in brushite cement was found to reduce the extent of brushite hydrolysis resulting in the formation of HA. By incorporating magnesium ions in the apatite reactant structure the concentration of magnesium ions in the liquid phase of the cement was controlled by the dissolution rate of the apatite. This approach may be used to supply other ions to cement systems during setting as a means to manipulate the clinical performance and characteristics of brushite cements.
Yoshimoto, Takuya; Goto, Taichi; Isogai, Ryosuke; Nakamura, Yuichi; Takagi, Hiroyuki; Ross, C A; Inoue, M
2016-04-18
Magnetophotonic crystals (MPCs) comprising cerium-substituted yttrium iron garnet (CeYIG) sandwiched by two Bragg mirrors were fabricated by vacuum annealing. CeYIG was deposited on Bragg mirrors at room temperature and annealed in 5 Pa of residual air. No ceria or other non-garnet phases were detected. Cerium 3 + ions substituted on the yttrium sites and no cerium 4 + ions were found. The Faraday rotation angle of the MPC was -2.92° at a wavelength of λ = 1570 nm was 30 times larger than that of the CeYIG film. These results showed good agreement with calculated values derived using a matrix approach.
Directory of Open Access Journals (Sweden)
Scott Barlowe
2017-06-01
Full Text Available Understanding how proteins mutate is critical to solving a host of biological problems. Mutations occur when an amino acid is substituted for another in a protein sequence. The set of likelihoods for amino acid substitutions is stored in a matrix and input to alignment algorithms. The quality of the resulting alignment is used to assess the similarity of two or more sequences and can vary according to assumptions modeled by the substitution matrix. Substitution strategies with minor parameter variations are often grouped together in families. For example, the BLOSUM and PAM matrix families are commonly used because they provide a standard, predefined way of modeling substitutions. However, researchers often do not know if a given matrix family or any individual matrix within a family is the most suitable. Furthermore, predefined matrix families may inaccurately reflect a particular hypothesis that a researcher wishes to model or otherwise result in unsatisfactory alignments. In these cases, the ability to compare the effects of one or more custom matrices may be needed. This laborious process is often performed manually because the ability to simultaneously load multiple matrices and then compare their effects on alignments is not readily available in current software tools. This paper presents SubVis, an interactive R package for loading and applying multiple substitution matrices to pairwise alignments. Users can simultaneously explore alignments resulting from multiple predefined and custom substitution matrices. SubVis utilizes several of the alignment functions found in R, a common language among protein scientists. Functions are tied together with the Shiny platform which allows the modification of input parameters. Information regarding alignment quality and individual amino acid substitutions is displayed with the JavaScript language which provides interactive visualizations for revealing both high-level and low-level alignment
Coan, Heather B.; Youker, Robert T.
2017-01-01
Understanding how proteins mutate is critical to solving a host of biological problems. Mutations occur when an amino acid is substituted for another in a protein sequence. The set of likelihoods for amino acid substitutions is stored in a matrix and input to alignment algorithms. The quality of the resulting alignment is used to assess the similarity of two or more sequences and can vary according to assumptions modeled by the substitution matrix. Substitution strategies with minor parameter variations are often grouped together in families. For example, the BLOSUM and PAM matrix families are commonly used because they provide a standard, predefined way of modeling substitutions. However, researchers often do not know if a given matrix family or any individual matrix within a family is the most suitable. Furthermore, predefined matrix families may inaccurately reflect a particular hypothesis that a researcher wishes to model or otherwise result in unsatisfactory alignments. In these cases, the ability to compare the effects of one or more custom matrices may be needed. This laborious process is often performed manually because the ability to simultaneously load multiple matrices and then compare their effects on alignments is not readily available in current software tools. This paper presents SubVis, an interactive R package for loading and applying multiple substitution matrices to pairwise alignments. Users can simultaneously explore alignments resulting from multiple predefined and custom substitution matrices. SubVis utilizes several of the alignment functions found in R, a common language among protein scientists. Functions are tied together with the Shiny platform which allows the modification of input parameters. Information regarding alignment quality and individual amino acid substitutions is displayed with the JavaScript language which provides interactive visualizations for revealing both high-level and low-level alignment information. PMID:28674656
Hierarchical matrix approximation of large covariance matrices
Litvinenko, Alexander
2015-01-07
We approximate large non-structured covariance matrices in the H-matrix format with a log-linear computational cost and storage O(n log n). We compute inverse, Cholesky decomposition and determinant in H-format. As an example we consider the class of Matern covariance functions, which are very popular in spatial statistics, geostatistics, machine learning and image analysis. Applications are: kriging and optimal design
Diagonalizing sensing matrix of broadband RSE
Sato, Shuichi; Kokeyama, Keiko; Kawazoe, Fumiko; Somiya, Kentaro; Kawamura, Seiji
2006-03-01
For a broadband-operated RSE interferometer, a simple and smart length sensing and control scheme was newly proposed. The sensing matrix could be diagonal, owing to a simple allocation of two RF modulations and to a macroscopic displacement of cavity mirrors, which cause a detuning of the RF modulation sidebands. In this article, the idea of the sensing scheme and an optimization of the relevant parameters will be described.
Institute of Scientific and Technical Information of China (English)
乐群星; 张高; 韩凤宇
2010-01-01
由于航天器等复杂产品设计过程中普遍存在的信息耦合现象,使得对复杂产品设计项目的定量化管理成为当前项目管理领域的一个难点.文章在布尔设计结构矩阵(Binary Design Structure Matrix, bDSM)的基础上,从任务输入信息的稳定性和对输入信息变动的敏感性两方面出发,运用模糊层次分析法将复杂产品设计过程中耦合任务集进行数字化设计结构矩阵(numerical DSM, nDSM)建模,定量描述任务间的信息关联强度,进而设计了适用于产品耦合设计过程的分解与重构的Epsilon算法,并针对产品设计过程nDSM模型的特点,设计了过程重组的优劣性评价标准,从而完成了对nDSM的分解与重组的评价和选择.
Formation of substituted oxa- and azarhodacyclobutanes.
Dauth, Alexander; Rigling, Carla; Tsoung, Jennifer; Love, Jennifer A
2013-12-01
The preparation of substituted oxa- and azarhodacyclobutanes is reported. After exchange of ethylene with a variety of unsymmetrically and symmetrically substituted alkenes, the corresponding rhodium-olefin complexes were oxidized with H2O2 and PhINTs (Ts=p-toluenesulfonyl) to yield the substituted oxa- and azarhodacyclobutanes, respectively. Oxarhodacyclobutanes could be prepared with excellent selectivity for incorporation of the oxygen atom on the more substituted carbon atom of the alkene. At the same time, azarhodacyclobutanes showed good-to-excellent selectivity for heteroatom incorporation on the less substituted carbon. Furthermore, it was shown that steric modifications of the ancillary ligand have a significant influence on the selectivity of Rh-olefin complex formation as well as formation of the substituted azametallacycles.
Trends in Substitution Models of Molecular Evolution
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Miguel eArenas
2015-10-01
Full Text Available Substitution models of evolution describe the process of genetic variation through fixed mutations and constitute the basis of the evolutionary analysis at the molecular level. Almost forty years after the development of first substitution models, highly sophisticated and data-specific substitution models continue emerging with the aim of better mimicking real evolutionary processes. Here I describe current trends in substitution models of DNA, codon and amino acid sequence evolution, including advantages and pitfalls of the most popular models. The perspective concludes that despite the large number of currently available substitution models, further research is required for more realistic modeling, especially for DNA coding and amino acid data. Additionally, the development of more accurate complex models should be coupled with new implementations and improvements of methods and frameworks for substitution model selection and downstream evolutionary analysis.
Bhatia, Rajendra
2013-01-01
This book is an outcome of the Indo-French Workshop on Matrix Information Geometries (MIG): Applications in Sensor and Cognitive Systems Engineering, which was held in Ecole Polytechnique and Thales Research and Technology Center, Palaiseau, France, in February 23-25, 2011. The workshop was generously funded by the Indo-French Centre for the Promotion of Advanced Research (IFCPAR). During the event, 22 renowned invited french or indian speakers gave lectures on their areas of expertise within the field of matrix analysis or processing. From these talks, a total of 17 original contribution or state-of-the-art chapters have been assembled in this volume. All articles were thoroughly peer-reviewed and improved, according to the suggestions of the international referees. The 17 contributions presented are organized in three parts: (1) State-of-the-art surveys & original matrix theory work, (2) Advanced matrix theory for radar processing, and (3) Matrix-based signal processing applications.
Currency substitution, portfolio diversification, and money demand
Freitas, Miguel Lebre de; Veiga, Francisco José
2006-01-01
We extend the Thomas (1985) dynamic optimising model of money demand and currency substitution to the case in which the individual has restricted or no access to foreign currency denominated bonds. In this case Currency Substitution decisions and Asset Substitution decisions are not separable. The results obtained suggest that the significance of an expected exchange rate depreciation term in the demand for domestic money provides a valid test for the presence of currency subst...
On topology optimization of plates with prestress
DEFF Research Database (Denmark)
Pedersen, Niels Leergaard
2001-01-01
In this work, topology optimization is used to optimize the compliance or eigenvalues of prestressed plates. The prestress is accounted for by including the force equivalent to the prestressing and adding the initial stress stiffness matrix to the original stiffness matrix. The calculation...... of the sensitivities is complicated because of the initial stress stiffness matrix, but the computational cost can be kept low by using the adjoint method. The topology optimization problem is solved using the solid isotropic material with penalization (SIMP) method in combination with method of moving asymptotes (MMA...
Inversion Free Algorithms for Computing the Principal Square Root of a Matrix
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Nicholas Assimakis
2014-01-01
Full Text Available New algorithms are presented about the principal square root of an n×n matrix A. In particular, all the classical iterative algorithms require matrix inversion at every iteration. The proposed inversion free iterative algorithms are based on the Schulz iteration or the Bernoulli substitution as a special case of the continuous time Riccati equation. It is certified that the proposed algorithms are equivalent to the classical Newton method. An inversion free algebraic method, which is based on applying the Bernoulli substitution to a special case of the continuous time Riccati equation, is also proposed.
Relaxing the Molecular Clock to Different Degrees for Different Substitution Types.
Lee, Hui-Jie; Rodrigue, Nicolas; Thorne, Jeffrey L
2015-08-01
Rates of molecular evolution can vary over time. Diverse statistical techniques for divergence time estimation have been developed to accommodate this variation. These typically require that all sequence (or codon) positions at a locus change independently of one another. They also generally assume that the rates of different types of nucleotide substitutions vary across a phylogeny in the same way. This permits divergence time estimation procedures to employ an instantaneous rate matrix with relative rates that do not differ among branches. However, previous studies have suggested that some substitution types (e.g., CpG to TpG changes in mammals) are more clock-like than others. As has been previously noted, this is biologically plausible given the mutational mechanism of CpG to TpG changes. Through stochastic mapping of sequence histories from context-independent substitution models, our approach allows for context-dependent nucleotide substitutions to change their relative rates over time. We apply our approach to the analysis of a 0.15 Mb intergenic region from eight primates. In accord with previous findings, we find comparatively little rate variation over time for CpG to TpG substitutions but we find more for other substitution types. We conclude by discussing the limitations and prospects of our approach.
Dehalogenation of aromatics by nucleophilic aromatic substitution.
Sadowsky, Daniel; McNeill, Kristopher; Cramer, Christopher J
2014-09-16
Nucleophilic aromatic substitution has been implicated as a mechanism for both the biotic and abiotic hydrodehalogenation of aromatics. Two mechanisms for the aqueous dehalogenation of aromatics involving nucleophilic aromatic substitution with hydride as a nucleophile are investigated using a validated density functional and continuum solvation protocol. For chlorinated and brominated aromatics, nucleophilic addition ortho to carbon-halogen bonds via an anionic intermediate is predicted to be the preferred mechanism in the majority of cases, while concerted substitution is predicted to be preferred for most fluorinated aromatics. Nucleophilic aromatic substitution reactions with the hydroxide and hydrosulfide anions as nucleophiles are also investigated and compared.
Phase diagram of matrix compressed sensing
Schülke, Christophe; Schniter, Philip; Zdeborová, Lenka
2016-12-01
In the problem of matrix compressed sensing, we aim to recover a low-rank matrix from a few noisy linear measurements. In this contribution, we analyze the asymptotic performance of a Bayes-optimal inference procedure for a model where the matrix to be recovered is a product of random matrices. The results that we obtain using the replica method describe the state evolution of the Parametric Bilinear Generalized Approximate Message Passing (P-BiG-AMP) algorithm, recently introduced in J. T. Parker and P. Schniter [IEEE J. Select. Top. Signal Process. 10, 795 (2016), 10.1109/JSTSP.2016.2539123]. We show the existence of two different types of phase transition and their implications for the solvability of the problem, and we compare the results of our theoretical analysis to the numerical performance reached by P-BiG-AMP. Remarkably, the asymptotic replica equations for matrix compressed sensing are the same as those for a related but formally different problem of matrix factorization.
Max–min distance nonnegative matrix factorization
Wang, Jim Jing-Yan
2014-10-26
Nonnegative Matrix Factorization (NMF) has been a popular representation method for pattern classification problems. It tries to decompose a nonnegative matrix of data samples as the product of a nonnegative basis matrix and a nonnegative coefficient matrix. The columns of the coefficient matrix can be used as new representations of these data samples. However, traditional NMF methods ignore class labels of the data samples. In this paper, we propose a novel supervised NMF algorithm to improve the discriminative ability of the new representation by using the class labels. Using the class labels, we separate all the data sample pairs into within-class pairs and between-class pairs. To improve the discriminative ability of the new NMF representations, we propose to minimize the maximum distance of the within-class pairs in the new NMF space, and meanwhile to maximize the minimum distance of the between-class pairs. With this criterion, we construct an objective function and optimize it with regard to basis and coefficient matrices, and slack variables alternatively, resulting in an iterative algorithm. The proposed algorithm is evaluated on three pattern classification problems and experiment results show that it outperforms the state-of-the-art supervised NMF methods.
Directory of Open Access Journals (Sweden)
J. Mukerji
1993-10-01
Full Text Available The present state of the knowledge of ceramic-matrix composites have been reviewed. The fracture toughness of present structural ceramics are not enough to permit design of high performance machines with ceramic parts. They also fail by catastrophic brittle fracture. It is generally believed that further improvement of fracture toughness is only possible by making composites of ceramics with ceramic fibre, particulate or platelets. Only ceramic-matrix composites capable of working above 1000 degree centigrade has been dealt with keeping reinforced plastics and metal-reinforced ceramics outside the purview. The author has discussed the basic mechanisms of toughening and fabrication of composites and the difficulties involved. Properties of available fibres and whiskers have been given. The best results obtained so far have been indicated. The limitations of improvement in properties of ceramic-matrix composites have been discussed.
Energy Technology Data Exchange (ETDEWEB)
Pan, Feng [Los Alamos National Laboratory; Kasiviswanathan, Shiva [Los Alamos National Laboratory
2010-01-01
In the matrix interdiction problem, a real-valued matrix and an integer k is given. The objective is to remove k columns such that the sum over all rows of the maximum entry in each row is minimized. This combinatorial problem is closely related to bipartite network interdiction problem which can be applied to prioritize the border checkpoints in order to minimize the probability that an adversary can successfully cross the border. After introducing the matrix interdiction problem, we will prove the problem is NP-hard, and even NP-hard to approximate with an additive n{gamma} factor for a fixed constant {gamma}. We also present an algorithm for this problem that achieves a factor of (n-k) mUltiplicative approximation ratio.
Extracellular matrix structure.
Theocharis, Achilleas D; Skandalis, Spyros S; Gialeli, Chrysostomi; Karamanos, Nikos K
2016-02-01
Extracellular matrix (ECM) is a non-cellular three-dimensional macromolecular network composed of collagens, proteoglycans/glycosaminoglycans, elastin, fibronectin, laminins, and several other glycoproteins. Matrix components bind each other as well as cell adhesion receptors forming a complex network into which cells reside in all tissues and organs. Cell surface receptors transduce signals into cells from ECM, which regulate diverse cellular functions, such as survival, growth, migration, and differentiation, and are vital for maintaining normal homeostasis. ECM is a highly dynamic structural network that continuously undergoes remodeling mediated by several matrix-degrading enzymes during normal and pathological conditions. Deregulation of ECM composition and structure is associated with the development and progression of several pathologic conditions. This article emphasizes in the complex ECM structure as to provide a better understanding of its dynamic structural and functional multipotency. Where relevant, the implication of the various families of ECM macromolecules in health and disease is also presented.
Finite Temperature Matrix Theory
Meana, M L; Peñalba, J P; Meana, Marco Laucelli; Peñalba, Jesús Puente
1998-01-01
We present the way the Lorentz invariant canonical partition function for Matrix Theory as a light-cone formulation of M-theory can be computed. We explicitly show how when the eleventh dimension is decompactified, the N=1 eleven dimensional SUGRA partition function appears. From this particular analysis we also clarify the question about the discernibility problem when making statistics with supergravitons (the N! problem) in Matrix black hole configurations. We also provide a high temperature expansion which captures some structure of the canonical partition function when interactions amongst D-particles are on. The connection with the semi-classical computations thermalizing the open superstrings attached to a D-particle is also clarified through a Born-Oppenheimer approximation. Some ideas about how Matrix Theory would describe the complementary degrees of freedom of the massless content of eleven dimensional SUGRA are also discussed.
Controversial issues of maternity substitution
Directory of Open Access Journals (Sweden)
Andy Pușcă
2009-06-01
Full Text Available Substitute maternity consists in a woman carrying a pregnancy (the implant of an embryo, at therequest of a sterile couple, most of the times in exchange of a sum of money, with her commitment tounconditionally give away the newborn after birth to the couple she concluded the agreement with. Manycontroversies emerged in what concerns the contract between the sterile couple and the carrying mother,especially when this contract is by onerous title, which happens in most of the cases. In that a civil contract? Is ita sales contract for the child? Is it a contract to provide services? Is it body marketing? Between total prohibitionand excessive liberalism, the middle way, which is the regulation according to ethical religious, cultural andsocial norms of each community, represents a realistic solution.
Monodromy Substitutions and Rational Blowdowns
Endo, Hisaaki; van Horn-Morris, Jeremy
2010-01-01
We introduce several new families of relations in the mapping class groups of planar surfaces, each equating two products of right-handed Dehn twists. The interest of these relations lies in their geometric interpretation in terms of rational blowdowns of 4-manifolds, specifically via monodromy substitution in Lefschetz fibrations. The simplest example is the lantern relation, already shown by the first author and Gurtas to correspond to rational blowdown along a -4 sphere; here we give relations that extend that result to realize the "generalized" rational blowdowns of Fintushel-Stern and Park by monodromy subsitution, as well as several of the families of rational blowdowns discovered by Stipsicz-Szab\\'o-Wahl.
Substitution dynamical systems spectral analysis
Queffélec, Martine
2010-01-01
This volume mainly deals with the dynamics of finitely valued sequences, and more specifically, of sequences generated by substitutions and automata. Those sequences demonstrate fairly simple combinatorical and arithmetical properties and naturally appear in various domains. As the title suggests, the aim of the initial version of this book was the spectral study of the associated dynamical systems: the first chapters consisted in a detailed introduction to the mathematical notions involved, and the description of the spectral invariants followed in the closing chapters. This approach, combined with new material added to the new edition, results in a nearly self-contained book on the subject. New tools - which have also proven helpful in other contexts - had to be developed for this study. Moreover, its findings can be concretely applied, the method providing an algorithm to exhibit the spectral measures and the spectral multiplicity, as is demonstrated in several examples. Beyond this advanced analysis, many...
Institute of Scientific and Technical Information of China (English)
徐德峰; 李庆仕; 孙力军; 王雅玲; 刘唤明; 叶日英; 李翩翩; 李敏红; 谢加旋
2013-01-01
以麸皮和豆粕的混合培养基发酵产抗菌脂肽是目前抗菌脂肽较大规模制备的主要工艺,但产率受提取过程中多因素的影响.运用数理统计工具Box-Behnken对影响芽孢杆菌抗菌脂肽提取的主要影响因素进行定量评价和优化.试验得出最佳提取条件为80％甲醇水溶液、料液比1∶5(m∶V)、浸提时间180 min、浸提pH6.0,在此参数下抗菌脂肽的提取量为72.49 g/kg,比优化前的59.14 g/kg提高了22.57％.%The current process for large scale preparation of antibacterial lipopeptides fermented on the mixed media of wheat bran and soybean meal,is influenced by many processing factors.Based on the results of one-factor-one-step experiments,ie.the types and concentration of extraction solvents,the ratio of feed to volume of solvent,immersion time and pH value,the main factors influencing extraction yield of antibacterial lipopeptides from Bacillus subtilis were quantitatively evaluated and optimized by statistical method and the optimal parameters were as follows:80％ methanol solvent,1:5 ratio of feed to solvent,180 minutes of immersion time,and 6.0 of pH value.Under these condition,the extraction yield of antibacterial lipopeptides reached 72.49 g/kg,22.57％ higher than the natural status of 59.14 g/kg.
Biodentine-a novel dentinal substitute for single visit apexification.
Nayak, Gurudutt; Hasan, Mohammad Faiz
2014-05-01
Use of an apical plug in management of cases with open apices has gained popularity in recent years. Biodentine, a new calcium silicate-based material has recently been introduced as a dentine substitute, whenever original dentine is damaged. This case report describes single visit apexification in a maxillary central incisor with necrotic pulp and open apex using Biodentine as an apical barrier, and a synthetic collagen material as an internal matrix. Following canal cleaning and shaping, calcium hydroxide was placed as an intracanal medicament for 1 mon. This was followed by placement of small piece of absorbable collagen membrane beyond the root apex to serve as matrix. An apical plug of Biodentine of 5 mm thickness was placed against the matrix using pre-fitted hand pluggers. The remainder of canal was back-filled with thermoplasticized gutta-percha and access cavity was restored with composite resin followed by all-ceramic crown. One year follow-up revealed restored aesthetics and function, absence of clinical signs and symptoms, resolution of periapical rarefaction, and a thin layer of calcific tissue formed apical to the Biodentine barrier. The positive clinical outcome in this case is encouraging for the use of Biodentine as an apical plug in single visit apexification procedures.
Biodentine-a novel dentinal substitute for single visit apexification
Directory of Open Access Journals (Sweden)
Gurudutt Nayak
2014-05-01
Full Text Available Use of an apical plug in management of cases with open apices has gained popularity in recent years. Biodentine, a new calcium silicate-based material has recently been introduced as a dentine substitute, whenever original dentine is damaged. This case report describes single visit apexification in a maxillary central incisor with necrotic pulp and open apex using Biodentine as an apical barrier, and a synthetic collagen material as an internal matrix. Following canal cleaning and shaping, calcium hydroxide was placed as an intracanal medicament for 1 mon. This was followed by placement of small piece of absorbable collagen membrane beyond the root apex to serve as matrix. An apical plug of Biodentine of 5 mm thickness was placed against the matrix using pre-fitted hand pluggers. The remainder of canal was back-filled with thermoplasticized gutta-percha and access cavity was restored with composite resin followed by all-ceramic crown. One year follow-up revealed restored aesthetics and function, absence of clinical signs and symptoms, resolution of periapical rarefaction, and a thin layer of calcific tissue formed apical to the Biodentine barrier. The positive clinical outcome in this case is encouraging for the use of Biodentine as an apical plug in single visit apexification procedures.
Photoelectron Spectroscopy of Substituted Phenylnitrenes
Wijeratne, Neloni R.; Fonte, Maria Da; Wenthold, Paul G.
2009-06-01
Nitrenes are unusual molecular structures with unfilled electronic valences that are isoelectronic with carbenes. Although, both can be generated by either thermal or photochemical decomposition of appropriate precursors they usually exhibit different reactivities. In this work, we carry out spectroscopic studies of substituted phenylnitrene to determine how the introduction of substituents will affect the reactivity and its thermochemical properties. All studies were carried out by using the newly constructed time-of-flight negative ion photoelectron spectrometer (NIPES) at Purdue University. The 355 nm photoelectron spectra of the o-, m-, and p-chlorophenyl nitrene anions are fairly similar to that measured for phenylnitrene anion. All spectra show low energy triplet state and a high energy singlet state. The singlet state for the meta isomer is well-resolved, with a well defined origin and observable vibrational structure. Whereas the singlet states for the ortho and para isomers have lower energy onsets and no resolved structure. The isomeric dependence suggests that the geometry differences result from the resonance interaction between the nitrogen and the substituent. Quinoidal resonance structures are possible for the open-shell singlet states of the o- and p-chlorinated phenyl nitrenes. The advantages of this type of electronic structures for the open-shell singlet states is that the unpaired electrons can be more localized on separate atoms in the molecules, minimizing the repulsion between. Because the meta position is not in resonance with the nitrenes, substitution at that position should not affect the structure of the open-shell singlet state. The measured electron affinities (EA) of the triplet phenylnitrenes are in excellent agreement with the values predicted by electronic structure calculations. The largest EA, 1.82 eV is found for the meta isomer, with para being the smallest, 1.70 eV.
Matrixed business support comparison study.
Energy Technology Data Exchange (ETDEWEB)
Parsons, Josh D.
2004-11-01
The Matrixed Business Support Comparison Study reviewed the current matrixed Chief Financial Officer (CFO) division staff models at Sandia National Laboratories. There were two primary drivers of this analysis: (1) the increasing number of financial staff matrixed to mission customers and (2) the desire to further understand the matrix process and the opportunities and challenges it creates.
Aoki, H; Kawai, H; Kitazawa, Y; Tada, T; Tsuchiya, A
1999-01-01
We review our proposal for a constructive definition of superstring, type IIB matrix model. The IIB matrix model is a manifestly covariant model for space-time and matter which possesses N=2 supersymmetry in ten dimensions. We refine our arguments to reproduce string perturbation theory based on the loop equations. We emphasize that the space-time is dynamically determined from the eigenvalue distributions of the matrices. We also explain how matter, gauge fields and gravitation appear as fluctuations around dynamically determined space-time.
Kitazawa, Y; Saito, O; Kitazawa, Yoshihisa; Mizoguchi, Shun'ya; Saito, Osamu
2006-01-01
We study the zero-dimensional reduced model of D=6 pure super Yang-Mills theory and argue that the large N limit describes the (2,0) Little String Theory. The one-loop effective action shows that the force exerted between two diagonal blocks of matrices behaves as 1/r^4, implying a six-dimensional spacetime. We also observe that it is due to non-gravitational interactions. We construct wave functions and vertex operators which realize the D=6, (2,0) tensor representation. We also comment on other "little" analogues of the IIB matrix model and Matrix Theory with less supercharges.
Hohn, Franz E
2012-01-01
This complete and coherent exposition, complemented by numerous illustrative examples, offers readers a text that can teach by itself. Fully rigorous in its treatment, it offers a mathematically sound sequencing of topics. The work starts with the most basic laws of matrix algebra and progresses to the sweep-out process for obtaining the complete solution of any given system of linear equations - homogeneous or nonhomogeneous - and the role of matrix algebra in the presentation of useful geometric ideas, techniques, and terminology.Other subjects include the complete treatment of the structur
Rheocasting Al Matrix Composites
Girot, F. A.; Albingre, L.; Quenisset, J. M.; Naslain, R.
1987-11-01
Aluminum alloy matrix composites reinforced by SiC short fibers (or whiskers) can be prepared by rheocasting, a process which consists of the incorporation and homogeneous distribution of the reinforcement by stirring within a semi-solid alloy. Using this technique, composites containing fiber volume fractions in the range of 8-15%, have been obtained for various fibers lengths (i.e., 1 mm, 3 mm and 6 mm for SiC fibers). This paper attempts to delineate the best compocasting conditions for aluminum matrix composites reinforced by short SiC (e.g Nicalon) or SiC whiskers (e.g., Tokamax) and characterize the resulting microstructures.
Frahm, K M
2016-01-01
Using parallels with the quantum scattering theory, developed for processes in nuclear and mesoscopic physics and quantum chaos, we construct a reduced Google matrix $G_R$ which describes the properties and interactions of a certain subset of selected nodes belonging to a much larger directed network. The matrix $G_R$ takes into account effective interactions between subset nodes by all their indirect links via the whole network. We argue that this approach gives new possibilities to analyze effective interactions in a group of nodes embedded in a large directed networks. Possible efficient numerical methods for the practical computation of $G_R$ are also described.
Density matrix perturbation theory.
Niklasson, Anders M N; Challacombe, Matt
2004-05-14
An orbital-free quantum perturbation theory is proposed. It gives the response of the density matrix upon variation of the Hamiltonian by quadratically convergent recursions based on perturbed projections. The technique allows treatment of embedded quantum subsystems with a computational cost scaling linearly with the size of the perturbed region, O(N(pert.)), and as O(1) with the total system size. The method allows efficient high order perturbation expansions, as demonstrated with an example involving a 10th order expansion. Density matrix analogs of Wigner's 2n+1 rule are also presented.
Energy Technology Data Exchange (ETDEWEB)
Brown, T.W.
2010-11-15
The same complex matrix model calculates both tachyon scattering for the c=1 non-critical string at the self-dual radius and certain correlation functions of half-BPS operators in N=4 super- Yang-Mills. It is dual to another complex matrix model where the couplings of the first model are encoded in the Kontsevich-like variables of the second. The duality between the theories is mirrored by the duality of their Feynman diagrams. Analogously to the Hermitian Kontsevich- Penner model, the correlation functions of the second model can be written as sums over discrete points in subspaces of the moduli space of punctured Riemann surfaces. (orig.)
Enhanced Thermoelectric Properties of W- and Fe-Substituted MnSi γ
Ghodke, Swapnil; Hiroishi, Naoya; Yamamoto, Akio; Ikuta, Hiroshi; Matsunami, Masaharu; Takeuchi, Tsunehiro
2016-10-01
We have investigated the effect of heavy-element (W) substitution on the thermoelectric properties of higher manganese silicide (HMS). Samples were prepared by arc melting followed by liquid quenching, where the latter assisted in achieving higher solubility for tungsten. We observed that Mn34.6W1.8Si63.6 was a p-type material, whereas simultaneous substitution of 12 at.% Fe made the higher manganese silicide an n-type material. The optimal carrier concentration was obtained by simultaneous substitution of Fe and W for Mn atoms. Although the samples were metastable, we successfully obtained bulk samples by a low-temperature (970 K), high-pressure (>100 MPa), long-duration sintering process. The lattice thermal conductivity was effectively reduced by W substitution, and the ZT value was improved to above 0.5 for both n- and p-type samples.
Optimal Provision of Public Goods with Rank Dependent Expected Utility.
Eide, Erling
2002-01-01
In this paper the theory of rank-dependent expected utility (RDEU) is substituted for the theory of expected utility (EU) in a model of optimal provision of public goods. The substitution generalizes the Samuelson rule, previously modified to include deadweight loss and tax evasion loss.
Large-scale portfolios using realized covariance matrix: evidence from the Japanese stock market
Masato Ubukata
2009-01-01
The objective of this paper is to examine effects of realized covariance matrix estimators based on intraday returns on large-scale minimum-variance equity portfolio optimization. We empirically assess out-of-sample performance of portfolios with different covariance matrix estimators: the realized covariance matrix estimators and Bayesian shrinkage estimators based on the past monthly and daily returns. The main results are: (1) the realized covariance matrix estimators using the past intrad...
40 CFR 721.5340 - Substituted benzothiazole-azo-substituted benzoquinoline nickel complex (generic).
2010-07-01
... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted benzothiazole-azo... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.5340 Substituted benzothiazole-azo... to reporting. (1) The chemical substance identified generically as substituted...
Renewable Substitutability Index: Maximizing Renewable Resource Use in Buildings
Directory of Open Access Journals (Sweden)
Ravi S. Srinivasan
2015-05-01
Full Text Available In order to achieve a material and energy balance in buildings that is sustainable in the long run, there is an urgent need to assess the renewable and non-renewable resources used in the manufacturing process and to progressively replace non-renewable resources with renewables. Such progressive disinvestment in the non-renewable resources that may be substituted with renewable resources is referred to as “Renewable Substitutability” and if implemented, this process will lead to a paradigm shift in the way building materials are manufactured. This paper discusses the development of a Renewable Substitutability Index (RSI that is designed to maximize the use of renewable resources in a building and quantifies the substitution process using solar emergy (i.e., the solar equivalent joules required for any item. The RSI of a building or a building component, i.e., floor or wall systems, etc., is the ratio of the renewable resources used during construction, including replacement and maintenance, to the building’s maximum renewable emergy potential. RSI values range between 0 and 1.0. A higher RSI achieves a low-energy building strategy promoting a higher order of sustainability by optimizing the use of renewables over a building’s lifetime from formation-extraction-manufacturing to maintenance, operation, demolition, and recycle.
DEFF Research Database (Denmark)
Frandsen, Gudmund Skovbjerg; Frandsen, Peter Frands
2009-01-01
We consider maintaining information about the rank of a matrix under changes of the entries. For n×n matrices, we show an upper bound of O(n1.575) arithmetic operations and a lower bound of Ω(n) arithmetic operations per element change. The upper bound is valid when changing up to O(n0.575) entri...... closed fields. The upper bound for element updates uses fast rectangular matrix multiplication, and the lower bound involves further development of an earlier technique for proving lower bounds for dynamic computation of rational functions.......We consider maintaining information about the rank of a matrix under changes of the entries. For n×n matrices, we show an upper bound of O(n1.575) arithmetic operations and a lower bound of Ω(n) arithmetic operations per element change. The upper bound is valid when changing up to O(n0.575) entries...... in a single column of the matrix. We also give an algorithm that maintains the rank using O(n2) arithmetic operations per rank one update. These bounds appear to be the first nontrivial bounds for the problem. The upper bounds are valid for arbitrary fields, whereas the lower bound is valid for algebraically...
Matrix Embedded Organic Synthesis
Kamakolanu, U. G.; Freund, F. T.
2016-05-01
In the matrix of minerals such as olivine, a redox reaction of the low-z elements occurs. Oxygen is oxidized to the peroxy state while the low-Z-elements become chemically reduced. We assign them a formula [CxHyOzNiSj]n- and call them proto-organics.
PERFORMANCE OF PULVERIZED SLAG-SUBSTITUTED CEMENT
Institute of Scientific and Technical Information of China (English)
无
1999-01-01
The Portland cement is equivalently substituted by slag micropowders with various specific areas. The workability,activity and acid-corrosion resistance of the slag-substituted cements are investigated,the activation of gypsum is discussed,also the porosity and pore distribution of mortars of the slag micropowders cement are determined by mercury intrusion porosimetry.
Multisensory integration, sensory substitution and visual rehabilitation
DEFF Research Database (Denmark)
Proulx, Michael J; Ptito, Maurice; Amedi, Amir
2014-01-01
Sensory substitution has advanced remarkably over the past 35 years since first introduced to the scientific literature by Paul Bach-y-Rita. In this issue dedicated to his memory, we describe a collection of reviews that assess the current state of neuroscience research on sensory substitution...
24 CFR 235.206 - Substitute mortgagors.
2010-04-01
... MORTGAGE INSURANCE AND ASSISTANCE PAYMENTS FOR HOME OWNERSHIP AND PROJECT REHABILITATION Contract Rights and Obligations-Homes for Lower Income Families § 235.206 Substitute mortgagors. (a) Selling mortgagor... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Substitute mortgagors....
Type Substitution for Object-Oriented Programming
DEFF Research Database (Denmark)
Schwartzbach, Michael Ignatieff; Palsberg, Jens
1990-01-01
Genericity allows the substitution of types in a class. This is usually obtained through parameterized classes, although they are inflexible since any class can be inherited but is not in itself parameterized. We suggest a new genericity mechanism, type substitution, which is a subclassing concep...
Biomechanical properties of four dermal substitutes
Institute of Scientific and Technical Information of China (English)
ZHANG Guo-an; NING Fang-gang; ZHAO Nan-ming
2007-01-01
@@ Many kinds of cell-free dermal substitutes have been developed during the past several years, however,their biomechanical properties, including hysteresis,stress relaxation, creep, and non-linear stress-strain, are still unknown. In this study, we tested these biomechanical characteristics of four dermal substitutes,and compared them with those of fresh human skin (FHS).
Apolipoprotein A-I mutant proteins having cysteine substitutions and polynucleotides encoding same
Oda, Michael N.; Forte, Trudy M.
2007-05-29
Functional Apolipoprotein A-I mutant proteins, having one or more cysteine substitutions and polynucleotides encoding same, can be used to modulate paraoxonase's arylesterase activity. These ApoA-I mutant proteins can be used as therapeutic agents to combat cardiovascular disease, atherosclerosis, acute phase response and other inflammatory related diseases. The invention also includes modifications and optimizations of the ApoA-I nucleotide sequence for purposes of increasing protein expression and optimization.
Aluminum substitution in goethite in lake ore
Directory of Open Access Journals (Sweden)
Carlson, L.
1995-06-01
Full Text Available The extent of substitution of Fe by Al in goethite in 32 lake ore samples collected from 11 lakes in Finland varied between 0 and 23 mol-%. The data indicated a negative relationship between Al-substitution and the particle size of lake ore. Differences in the Al-substitution were apparent between sampling sites, suggesting that kinetic and environmental variation in lake ore formation influences the substitution. Non-substituted goethite is formed in coarse-grained sediments with locally high concentrations of Fe due to iron-rich springs. Unit cell edge lengths and volumes of goethite varied as function of Al-subsitution but deviated from the Vegard relationship towards higher values.
Improved production of membrane proteins in Escherichia coli by selective codon substitutions
DEFF Research Database (Denmark)
Nørholm, Morten H.H.; Toddo, Stephen; Virkki, Minttu T.I.
2013-01-01
K) for membrane transporters. For both coding sequences, synonymous codon substitutions in the region adjacent to the AUG start led to significant improvements in expression, whereas multi-parameter sequence optimization of codons throughout the coding sequence failed. We conclude that coding sequences can be re...
Lacome, Mathieu; Piscione, Julien; Hager, Jean-Philippe; Carling, Christopher
2016-09-01
To investigate the patterns and performance of substitutions in 18 international 15-a-side men's rugby union matches. A semiautomatic computerized time-motion system compiled 750 performance observations for 375 players (422 forwards, 328 backs). Running and technical-performance measures included total distance run, high-intensity running (>18.0 km/h), number of individual ball possessions and passes, percentage of passes completed, and number of attempted and percentage of successful tackles. A total of 184 substitutions (85.2%) were attributed to tactical and 32 (14.8%) to injury purposes respectively. The mean period for non-injury-purpose substitutions in backs (17.7%) occurred between 70 and 75 min, while forward substitutions peaked equally between 50-55 and 60-65 min (16.4%). Substitutes generally demonstrated improved running performance compared with both starter players who completed games and players whom they replaced (small differences, ES -0.2 to 0.5) in both forwards and backs over their entire time played. There was also a trend for better running performance in forward and back substitutes over their first 10 min of play compared with the final 10 min for replaced players (small to moderate differences, ES 0.3-0.6). Finally, running performance in both forward and back substitutes was generally lower (ES -0.1 to 0.3, unclear or small differences) over their entire 2nd-half time played compared with their first 10 min of play. The impact of substitutes on technical performance was generally considered unclear. This information provides practitioners with practical data relating to the physical and technical contributions of substitutions that subsequently could enable optimization of their impact on match play.
Managing time-substitutable electricity usage using dynamic controls
Energy Technology Data Exchange (ETDEWEB)
Ghosh, Soumyadip; Hosking, Jonathan R.; Natarajan, Ramesh; Subramaniam, Shivaram; Zhang, Xiaoxuan
2017-02-21
A predictive-control approach allows an electricity provider to monitor and proactively manage peak and off-peak residential intra-day electricity usage in an emerging smart energy grid using time-dependent dynamic pricing incentives. The daily load is modeled as time-shifted, but cost-differentiated and substitutable, copies of the continuously-consumed electricity resource, and a consumer-choice prediction model is constructed to forecast the corresponding intra-day shares of total daily load according to this model. This is embedded within an optimization framework for managing the daily electricity usage. A series of transformations are employed, including the reformulation-linearization technique (RLT) to obtain a Mixed-Integer Programming (MIP) model representation of the resulting nonlinear optimization problem. In addition, various regulatory and pricing constraints are incorporated in conjunction with the specified profit and capacity utilization objectives.
Managing time-substitutable electricity usage using dynamic controls
Energy Technology Data Exchange (ETDEWEB)
Ghosh, Soumyadip; Hosking, Jonathan R.; Natarajan, Ramesh; Subramaniam, Shivaram; Zhang, Xiaoxuan
2017-02-07
A predictive-control approach allows an electricity provider to monitor and proactively manage peak and off-peak residential intra-day electricity usage in an emerging smart energy grid using time-dependent dynamic pricing incentives. The daily load is modeled as time-shifted, but cost-differentiated and substitutable, copies of the continuously-consumed electricity resource, and a consumer-choice prediction model is constructed to forecast the corresponding intra-day shares of total daily load according to this model. This is embedded within an optimization framework for managing the daily electricity usage. A series of transformations are employed, including the reformulation-linearization technique (RLT) to obtain a Mixed-Integer Programming (MIP) model representation of the resulting nonlinear optimization problem. In addition, various regulatory and pricing constraints are incorporated in conjunction with the specified profit and capacity utilization objectives.
Managing time-substitutable electricity usage using dynamic controls
Ghosh, Soumyadip; Hosking, Jonathan R.; Natarajan, Ramesh; Subramaniam, Shivaram; Zhang, Xiaoxuan
2017-02-07
A predictive-control approach allows an electricity provider to monitor and proactively manage peak and off-peak residential intra-day electricity usage in an emerging smart energy grid using time-dependent dynamic pricing incentives. The daily load is modeled as time-shifted, but cost-differentiated and substitutable, copies of the continuously-consumed electricity resource, and a consumer-choice prediction model is constructed to forecast the corresponding intra-day shares of total daily load according to this model. This is embedded within an optimization framework for managing the daily electricity usage. A series of transformations are employed, including the reformulation-linearization technique (RLT) to obtain a Mixed-Integer Programming (MIP) model representation of the resulting nonlinear optimization problem. In addition, various regulatory and pricing constraints are incorporated in conjunction with the specified profit and capacity utilization objectives.
ON SOLUTIONS OF MATRIX EQUATION AXAT + BYBT = C
Institute of Scientific and Technical Information of China (English)
Yuan-bei Deng; Xi-yan Hu
2005-01-01
By making use of the quotient singular value decomposition (QSVD) of a matrix pair,this paper establishes the necessary and sufficient conditions for the existence of and the expressions for the general solutions of the linear matrix equation AXAT + BYBT = C with the unknown X and Y, which may be both symmetric, skew-symmetric, nonnegative definite , positive definite or some cross combinations respectively. Also, the solutions of some optimal problems are derived.
Preclinical evaluation of injectable bone substitute materials.
Bongio, Matilde; van den Beucken, Jeroen J J P; Leeuwenburgh, Sander C G; Jansen, John A
2015-03-01
Injectable bone substitutes (IBSs) represent an attractive class of ready-to-use biomaterials, both ceramic- and polymer-based, as they offer the potential benefit of minimally invasive surgery and optimal defect filling. Although in vitro assessments are the first step in the process of development, the safety and efficacy of an IBS strongly depend on validated preclinical research prior to clinical trials. However, the selection of a suitable preclinical model for performance evaluation of an IBS remains a challenge, as no gold standard exists to define the best animal model. In order to succeed in this attempt, we identified three stages of development, including (a) proof-of-principle, (b) predictive validity and (c) general scientific legitimacy, and the respective criteria that should be applied for such selection. The second part of this review provides an overview of commonly used animals for IBSs. Specifically, scientific papers published between January 1996 and March 2012 were retrieved that report the use of preclinical models for the evaluation of IBSs in situations requiring bone healing and bone augmentation. This review is meant not only to describe the currently available preclinical models for IBS application, but also to address critical considerations of such multi-factorial evaluation models (including animal species, strain, age, anatomical site, defect size and type of bone), which can be indicative but in most cases edge away from the human reality. Consequently, the ultimate goal is to guide researchers toward a more careful and meaningful interpretation of the results of experiments using animal models and their clinical applications. Copyright © 2012 John Wiley & Sons, Ltd.
Substituted hydroxyapatites with antibacterial properties.
Kolmas, Joanna; Groszyk, Ewa; Kwiatkowska-Różycka, Dagmara
2014-01-01
Reconstructive surgery is presently struggling with the problem of infections located within implantation biomaterials. Of course, the best antibacterial protection is antibiotic therapy. However, oral antibiotic therapy is sometimes ineffective, while administering an antibiotic at the location of infection is often associated with an unfavourable ratio of dosage efficiency and toxic effect. Thus, the present study aims to find a new factor which may improve antibacterial activity while also presenting low toxicity to the human cells. Such factors are usually implemented along with the implant itself and may be an integral part of it. Many recent studies have focused on inorganic factors, such as metal nanoparticles, salts, and metal oxides. The advantages of inorganic factors include the ease with which they can be combined with ceramic and polymeric biomaterials. The following review focuses on hydroxyapatites substituted with ions with antibacterial properties. It considers materials that have already been applied in regenerative medicine (e.g., hydroxyapatites with silver ions) and those that are only at the preliminary stage of research and which could potentially be used in implantology or dentistry. We present methods for the synthesis of modified apatites and the antibacterial mechanisms of various ions as well as their antibacterial efficiency.
Substituted Hydroxyapatites with Antibacterial Properties
Directory of Open Access Journals (Sweden)
Joanna Kolmas
2014-01-01
Full Text Available Reconstructive surgery is presently struggling with the problem of infections located within implantation biomaterials. Of course, the best antibacterial protection is antibiotic therapy. However, oral antibiotic therapy is sometimes ineffective, while administering an antibiotic at the location of infection is often associated with an unfavourable ratio of dosage efficiency and toxic effect. Thus, the present study aims to find a new factor which may improve antibacterial activity while also presenting low toxicity to the human cells. Such factors are usually implemented along with the implant itself and may be an integral part of it. Many recent studies have focused on inorganic factors, such as metal nanoparticles, salts, and metal oxides. The advantages of inorganic factors include the ease with which they can be combined with ceramic and polymeric biomaterials. The following review focuses on hydroxyapatites substituted with ions with antibacterial properties. It considers materials that have already been applied in regenerative medicine (e.g., hydroxyapatites with silver ions and those that are only at the preliminary stage of research and which could potentially be used in implantology or dentistry. We present methods for the synthesis of modified apatites and the antibacterial mechanisms of various ions as well as their antibacterial efficiency.
Uproar over Milk Substitutes Act.
1993-11-15
Health policy activists lobbied 7 years for the Infant Milk Substitutes, Feeding Bottles and Infant Food Bill. Proponents of the bill say that it basically curtails unethical marketing practices, not the sales of baby foods, and argue that it was conceived to reduce the trend of mothers over-diluting commercial milk in order to reduce household expenses as well as stem the potential erosion of knowledge on locally available weaning foods. Even though the bill will become an Act only after its rules and regulations have been finalized, the government has already banned baby food advertisements on television and in other electronic media under its control. Women's groups now argue that the bill tends to focus almost exclusively upon the welfare of children and compromises the position of women who can not lactate adequately. Moreover, they hold that the bill may be used to compel wives to stay out of the formal workforce so that they may feed their babies. The intention of the bill may be meaningless without complementary legislation addressing the problems of working mothers. Specifically, amendments to the Maternity Benefits Act of 1961 would extend maternity leave to 4 months after delivery and lengthen the duration of nursing breaks. It is, however, feared that these changes may reduce employment prospects for women.
Substituted androstanes as aromatase inhibitors
Energy Technology Data Exchange (ETDEWEB)
Levina, Inna S [N.D.Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow (Russian Federation)
1998-11-30
The synthesis and structure-activity relationships of inhibitors of steroid aromatase which catalyses the last stage of a multistep biotransformation of cholesterol into estrogens, viz., aromatisation of C{sub 19}-steroids into C{sub 18}-phenolic steroids, are discussed. Compounds of the androstane series which are structurally related to the natural substrate, viz., androst-4-ene-3,17-dione, are the subjects of consideration. The review encompasses problems of synthesis of various substituted androstanes and their aromatase-inhibiting activities and structural requirements for selective specific aromatase inhibitors based on in vitro and in vivo structure-activity studies of compounds synthesised, their biological properties and the results of clinical trials. Special attention is paid to practical applications of aromatase inhibitors in the treatment of hormone-dependent mammary and ovarian tumours as well as benign prostatic tumours. In writing this report, the author has used all the information currently available in the chemical, biochemical, endocrinological and medicinal literature as well as in patents. The bibliography includes 173 references.
Substituted androstanes as aromatase inhibitors
Levina, Inna S.
1998-11-01
The synthesis and structure-activity relationships of inhibitors of steroid aromatase which catalyses the last stage of a multistep biotransformation of cholesterol into estrogens, viz., aromatisation of C19-steroids into C18-phenolic steroids, are discussed. Compounds of the androstane series which are structurally related to the natural substrate, viz., androst-4-ene-3,17-dione, are the subjects of consideration. The review encompasses problems of synthesis of various substituted androstanes and their aromatase-inhibiting activities and structural requirements for selective specific aromatase inhibitors based on in vitro and in vivo structure-activity studies of compounds synthesised, their biological properties and the results of clinical trials. Special attention is paid to practical applications of aromatase inhibitors in the treatment of hormone-dependent mammary and ovarian tumours as well as benign prostatic tumours. In writing this report, the author has used all the information currently available in the chemical, biochemical, endocrinological and medicinal literature as well as in patents. The bibliography includes 173 references.
Electrotactile vision substitution for 3D trajectory following
Chekhchoukh, Abdessalem; Vuillerme, Nicolas; Payan, Yohan; Glade, Nicolas
2013-01-01
Navigation for blind persons represents a challenge for researchers in vision substitution. In this field, one of the used techniques to navigate is guidance. In this study, we develop a new approach for 3D trajectory following in which the requested task is to track a light path using computer input devices (keyboard and mouse) or a rigid body handled in front of a stereoscopic camera. The light path is visualized either on direct vision or by way of a electro-stimulation device, the Tongue Display Unit, a 12x12 matrix of electrodes. We improve our method by a series of experiments in which the effect of the modality of perception and that of the input device. Preliminary results indicated a close correlation between the stimulated and recorded trajectories.
Determination of optimal gains for constrained controllers
Energy Technology Data Exchange (ETDEWEB)
Kwan, C.M.; Mestha, L.K.
1993-08-01
In this report, we consider the determination of optimal gains, with respect to a certain performance index, for state feedback controllers where some elements in the gain matrix are constrained to be zero. Two iterative schemes for systematically finding the constrained gain matrix are presented. An example is included to demonstrate the procedures.
Szawkało, Joanna; Czarnocki, Zbigniew
2016-01-01
Summary A series of differently substituted 3,5-diaryl-2,4,6-trimethylpyridines were prepared and characterized using the Suzuki–Miyaura coupling reaction with accordingly selected bromo-derivatives and arylboronic acids. The reaction conditions were carefully optimized allowing high yield of isolated products and also the construction of unsymmetrically substituted diarylpyridines, difficult to access by other methods. PMID:27340474
First principles investigation of substituted strontium hexaferrite
Dixit, Vivek
This dissertation investigates how the magnetic properties of strontium hexaferrite change upon the substitution of foreign atoms at the Fe sites. Strontium hexaferrite, SrFe12O19, is a commonly used hard magnetic material and is produced in large quantities (around 500,000 tons per year). For different applications of strontium hexaferrite, its magnetic properties can be tuned by a proper substitution of the foreign atoms. Experimental screening for a proper substitution is a cost-intensive and time-consuming process, whereas computationally it can be done more efficiently. We used the 'density functional theory' a first principles based method to study substituted strontium hexaferrite. The site occupancies of the substituted atoms were estimated by calculating the substitution energies of different configurations. The formation probabilities of configurations were used to calculate the magnetic properties of substituted strontium hexaferrite. In the first study, Al-substituted strontium hexaferrite, SrFe12-x AlxO19 with x=0.5 and x=1.0 were investigated. It was found that at the annealing temperature the non-magnetic Al +3 ions preferentially replace Fe+3 ions from the 12 k and 2a sites. We found that the magnetization decreases and the magnetic anisotropy field increases as the fraction, x of the Al atoms increases. In the second study, SrFe12-xGaxO19 and SrFe12-xInxO19 with x=0.5 and x=1.0 were investigated. In the case of SrFe12-xGaxO19, the sites where Ga+3 ions prefer to enter are: 12 k, 2a, and 4f1. For SrFe12-xInxO19, In+3 ions most likely to occupy the 12k, 4f1 , and 4f2 sites. In both cases the magnetization was found to decrease slightly as the fraction of substituted atom increases. The magnetic anisotropy field increased for SrFe12-xGaxO 19, and decreased for SrFe12-xInxO19 as the concentration of substituted atoms increased. In the third study, 23 elements (M) were screened for their possible substitution in strontium hexaferrite, SrFe12-xMxO 19
Darga, Alexander; Kecht, Johann; Bein, Thomas
2007-12-18
The incorporation of organic moieties into siliceous frameworks leads to a wide variety of adsorbate-adsorbent interactions including weak van-der-Waal attractions as well as strong interactions such as Coulomb forces. Depending on the desired properties of such substituted highly porous matrix materials, optimized synthesis routes can be established to enhance the desired internal pore surface-affinity toward certain volatile compounds. On the basis of a fundamental knowledge of the host-guest system, sorption-related applications may benefit from individually fine-tuned and modified sample materials. The sorption isotherms of vaporized toluene on nonmodified and phenyl-functionalized mesoporous silica samples were determined on an acoustic wave device at different temperatures. The mesoporous silica was modified by in situ co-condensation and postsynthesis grafting approaches, respectively. All samples were thoroughly characterized by nitrogen sorption, thermogravimetric analysis (TGA), scanning and transmission electron microscopy (SEM, TEM), solid-state nuclear magnetic resonance (29Si NMR), dynamic light scattering (DLS), Raman spectroscopy, and toluene adsorption on a quartz crystal microbalance (QCM). The different heats of adsorption of toluene on the various modified silica surfaces obtained by the sorption data make it possible to gain additional information about the degree and type of surface functionalization. It is thus demonstrated that QCM studies can be a powerful and convenient tool for efficient investigations of functionalized mesoporous silica particles that yield valuable quantitative information on molecule-surface interactions.
Energy Technology Data Exchange (ETDEWEB)
Mohanta, Ojaswini [Council for Scientific and Industrial Research, National Metallurgical Laboratory, Jamshedpur 831 007 (India); Basumallick, A. [Bengal Engineering and Science University, Shibpur, West Bengal (India); Mitra, A. [Council for Scientific and Industrial Research, National Metallurgical Laboratory, Jamshedpur 831 007 (India); Panda, A.K., E-mail: akpanda@nmlindia.or [Council for Scientific and Industrial Research, National Metallurgical Laboratory, Jamshedpur 831 007 (India)
2010-01-15
The effect of substituting Al for Si in Co{sub 36}Fe{sub 36}Si{sub 4-x}Al{sub x}B{sub 20}Nb{sub 4}, (X=0, 0.5, 1.0, 1.5, 2.0 at%) alloys prepared in the form of melt-spun ribbons have been investigated. All the alloys were amorphous in their as-cast state. The onset of crystallization as observed using differential scanning calorimetry (DSC) was found to rise at low Al content up to X=1 at% beyond which there was a decreasing trend. The alloys also exhibited glass transition at 'T{sub g}'. Microstructural studies of optimally annealed samples indicated finer dispersions of nanoparticles in amorphous matrix which were identified as bcc-(FeCo)Si and bcc-(FeCo)SiAl nanophases by X-ray diffraction technique. Alloy with optimum content of Al around X=1 at% exhibited stability in coercivity at elevated temperatures. Though Al addition is known to lower magnetostriction, such consistency in coercivity may also be attributed towards lowering in the nanoparticle size compared to X=0 alloy. In the nanostructured state, the alloy containing optimum Al content (X=1) exhibited further enhancement in ferromagnetic ordering or the Curie temperature by 100 K compared to alloy without Al. Such addition also attributed to better frequency response of coercivity and low core losses.
Wong, Kin-Yiu; Richard, John P; Gao, Jiali
2009-10-01
Primary kinetic isotope effects (KIEs) on a series of carboxylic acid-catalyzed protonation reactions of aryl-substituted alpha-methoxystyrenes (X-1) to form oxocarbenium ions have been computed using the second-order Kleinert variational perturbation theory (KP2) in the framework of Feynman path integrals (PI) along with the potential energy surface obtained at the B3LYP/6-31+G(d,p) level. Good agreement with the experimental data was obtained, demonstrating that this novel computational approach for computing KIEs of organic reactions is a viable alternative to the traditional method employing Bigeleisen equation and harmonic vibrational frequencies. Although tunneling makes relatively small contributions to the lowering of the free energy barriers for the carboxylic acid catalyzed protonation reaction, it is necessary to include tunneling contributions to obtain quantitative estimates of the KIEs. Consideration of anharmonicity can further improve the calculated KIEs for the protonation of substituted alpha-methoxystyrenes by chloroacetic acid, but for the reactions of the parent and 4-NO(2) substituted alpha-methoxystyrene with substituted carboxylic acids, the correction of anharmonicity overestimates the computed KIEs for strong acid catalysts. In agreement with experimental findings, the largest KIEs are found in nearly ergoneutral reactions, DeltaG(o) approximately 0, where the transition structures are nearly symmetric and the reaction barriers are relatively low. Furthermore, the optimized transition structures are strongly dependent on the free energy for the formation of the carbocation intermediate, that is, the driving force DeltaG(o), along with a good correlation of Hammond shift in the transition state structure.
Institute of Scientific and Technical Information of China (English)
顾天意; 梁承姬
2012-01-01
To solve the Storage Space Allocation Problem (SSAP), an optimization strategy for the storage space allocation is proposed based on the Matrix Genetic Algorithm ( M-GA). The strategy aims at minimizing the transportation distance between the storage blocks and the vessel berths, and the factors such as quay crane and yard crane are taken into account. The storage space allocation model based on quay crane operating lines is built firstly; then the extended version of the SSAP is resolved by the M-GA; the influences of different genetic strategies on the performance of Genetic Algorithm (GA) are analyzed finally. The case of Shanghai Zhanghuabang Container Terminal verifies the superiority of the proposed method.%为解决堆场空间资源配置问题(Storage Space Allocation Problem,SSAP),以箱区到泊位运输距离最小为目标,综合考虑岸桥、场桥等因素,提出一种基于矩阵式遗传算法(Matrix Genetic Algorithm,M-GA)的集装箱码头堆场空间资源分配优化策略.该方法首先建立基于装卸作业面的堆场空间资源分配模型；然后运用M-GA求解扩展后的SSAP；最后分析不同遗传策略对遗传算法( Genetic Algorithm,GA)性能的影响,并以上海张华浜码头的案例验证该方法的优越性.
Dijkgraaf, Robbert; Verlinde, Erik; Verlinde, Herman
1997-02-01
Via compactification on a circle, the matrix mode] of M-theory proposed by Banks et a]. suggests a concrete identification between the large N limit of two-dimensional N = 8 supersymmetric Yang-Mills theory and type IIA string theory. In this paper we collect evidence that supports this identification. We explicitly identify the perturbative string states and their interactions, and describe the appearance of D-particle and D-membrane states.
Energy Technology Data Exchange (ETDEWEB)
Dijkgraaf, R. [Amsterdam Univ. (Netherlands). Dept. of Mathematics; Verlinde, E. [TH-Division, CERN, CH-1211 Geneva 23 (Switzerland)]|[Institute for Theoretical Physics, Universtity of Utrecht, 3508 TA Utrecht (Netherlands); Verlinde, H. [Institute for Theoretical Physics, University of Amsterdam, 1018 XE Amsterdam (Netherlands)
1997-09-01
Via compactification on a circle, the matrix model of M-theory proposed by Banks et al. suggests a concrete identification between the large N limit of two-dimensional N=8 supersymmetric Yang-Mills theory and type IIA string theory. In this paper we collect evidence that supports this identification. We explicitly identify the perturbative string states and their interactions, and describe the appearance of D-particle and D-membrane states. (orig.).
Dijkgraaf, R; Verlinde, Herman L
1997-01-01
Via compactification on a circle, the matrix model of M-theory proposed by Banks et al suggests a concrete identification between the large N limit of two-dimensional N=8 supersymmetric Yang-Mills theory and type IIA string theory. In this paper we collect evidence that supports this identification. We explicitly identify the perturbative string states and their interactions, and describe the appearance of D-particle and D-membrane states.
Felder, G; Felder, Giovanni; Riser, Roman
2004-01-01
We study a class of holomorphic matrix models. The integrals are taken over middle dimensional cycles in the space of complex square matrices. As the size of the matrices tends to infinity, the distribution of eigenvalues is given by a measure with support on a collection of arcs in the complex planes. We show that the arcs are level sets of the imaginary part of a hyperelliptic integral connecting branch points.
Matrix identity and tractional forces influence indirect cardiac reprogramming
Kong, Yen P.; Carrion, Bita; Singh, Rahul K.; Putnam, Andrew J.
2013-12-01
Heart regeneration through in vivo cardiac reprogramming has been demonstrated as a possible regenerative strategy. While it has been reported that cardiac reprogramming in vivo is more efficient than in vitro, the influence of the extracellular microenvironment on cardiac reprogramming remains incompletely understood. This understanding is necessary to improve the efficiency of cardiac reprogramming in order to implement this strategy successfully. Here we have identified matrix identity and cell-generated tractional forces as key determinants of the dedifferentiation and differentiation stages during reprogramming. Cell proliferation, matrix mechanics, and matrix microstructure are also important, but play lesser roles. Our results suggest that the extracellular microenvironment can be optimized to enhance cardiac reprogramming.
Neutron Multiplicity: LANL W Covariance Matrix for Curve Fitting
Energy Technology Data Exchange (ETDEWEB)
Wendelberger, James G. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2016-12-08
In neutron multiplicity counting one may fit a curve by minimizing an objective function, χ$2\\atop{n}$. The objective function includes the inverse of an n by n matrix of covariances, W. The inverse of the W matrix has a closed form solution. In addition W^{-1} is a tri-diagonal matrix. The closed form and tridiagonal nature allows for a simpler expression of the objective function χ$2\\atop{n}$. Minimization of this simpler expression will provide the optimal parameters for the fitted curve.
Modeling competitive substitution in a polyelectrolyte complex
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Peng, B.; Muthukumar, M., E-mail: muthu@polysci.umass.edu [Department of Polymer Science and Engineering, University of Massachusetts Amherst, Amherst, Massachusetts 01003 (United States)
2015-12-28
We have simulated the invasion of a polyelectrolyte complex made of a polycation chain and a polyanion chain, by another longer polyanion chain, using the coarse-grained united atom model for the chains and the Langevin dynamics methodology. Our simulations reveal many intricate details of the substitution reaction in terms of conformational changes of the chains and competition between the invading chain and the chain being displaced for the common complementary chain. We show that the invading chain is required to be sufficiently longer than the chain being displaced for effecting the substitution. Yet, having the invading chain to be longer than a certain threshold value does not reduce the substitution time much further. While most of the simulations were carried out in salt-free conditions, we show that presence of salt facilitates the substitution reaction and reduces the substitution time. Analysis of our data shows that the dominant driving force for the substitution process involving polyelectrolytes lies in the release of counterions during the substitution.
Matrix groups for undergraduates
Tapp, Kristopher
2016-01-01
Matrix groups touch an enormous spectrum of the mathematical arena. This textbook brings them into the undergraduate curriculum. It makes an excellent one-semester course for students familiar with linear and abstract algebra and prepares them for a graduate course on Lie groups. Matrix Groups for Undergraduates is concrete and example-driven, with geometric motivation and rigorous proofs. The story begins and ends with the rotations of a globe. In between, the author combines rigor and intuition to describe the basic objects of Lie theory: Lie algebras, matrix exponentiation, Lie brackets, maximal tori, homogeneous spaces, and roots. This second edition includes two new chapters that allow for an easier transition to the general theory of Lie groups. From reviews of the First Edition: This book could be used as an excellent textbook for a one semester course at university and it will prepare students for a graduate course on Lie groups, Lie algebras, etc. … The book combines an intuitive style of writing w...
Directory of Open Access Journals (Sweden)
Pradeep K. Rohatgi
1993-10-01
Full Text Available This paper reviews the world wide upsurge in metal matrix composite research and development activities with particular emphasis on cast metal-matrix particulate composites. Extensive applications of cast aluminium alloy MMCs in day-to-day use in transportation as well as durable good industries are expected to advance rapidly in the next decade. The potential for extensive application of cast composites is very large in India, especially in the areas of transportation, energy and electromechanical machinery; the extensive use of composites can lead to large savings in materials and energy, and in several instances, reduce environmental pollution. It is important that engineering education and short-term courses be organized to bring MMCs to the attention of students and engineering industry leaders. India already has excellent infrastructure for development of composites, and has a long track record of world class research in cast metal matrix particulate composites. It is now necessary to catalyze prototype and regular production of selected composite components, and get them used in different sectors, especially railways, cars, trucks, buses, scooters and other electromechanical machinery. This will require suitable policies backed up by funding to bring together the first rate talent in cast composites which already exists in India, to form viable development groups followed by setting up of production plants involving the process engineering capability already available within the country. On the longer term, cast composites should be developed for use in energy generation equipment, electronic packaging aerospace systems, and smart structures.
Fluid substitution based on seismic data of sand reservoirs%砂岩油藏地震数据流体替换
Institute of Scientific and Technical Information of China (English)
李景叶
2012-01-01
流体替换常用于计算油藏流体变化前后岩石弹性参数变化,是进行地震油藏描述与监测研究的关键步骤.流体替换需要孔隙度、岩石基质、流体属性和泥质含量等数据信息,因此目前往往只能在有测井数据的油藏部分进行流体替换,并通过地震数值模拟获取流体变化前后地震响应,从而进行地震属性分析与优化.为了扩大流体替换应用范围,提出利用地震资料直接进行流体替换.在确定油藏流体类型与岩石物理模型基础上,建立油藏地质模型,模拟油藏流体变化前后地震反射振幅峰值关系,并分析储层参数(包括孔隙度、储层厚度和泥质含量等)变化时该振幅关系变化特征.采用曲线拟合方式对该振幅峰值关系进行计算,得到可直接应用于地震数据的流体替换线性拟合方程,从而进行实际地震数据流体替换.基于胶结砂岩油藏岩石物理模型的模拟分析与实际资料应用试验,证明了基于地震数据流体替换的可行性.%Fluid substitution is commonly used to compute elastic property parameters of rocks before and after the variation of reservoir fluids, which is s key procedure in seismic reservoir characterization and monitoring. However, fluid substitution requires the information on parameters of rock porosity and matrix, fluid properties, clay content, etc. Therefore, at present fluid substitution can be only conducted on the part of a reservoir that has available log data, and the dynamic seismic response of fluid variations is obtained through seismic numerical simulation during seismic attribute analysis and optimization. In order to expand the application of fluid substitution, we proposed to directly conduct fluid substitution by utilizing seismic data, in which a geologic model of oil reservoirs was established to simulate the amplitude peak-value correlation of seismic reflection between wet and gas reservoirs according to the
Determinants of generic drug substitution in Switzerland
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Lufkin Thomas M
2011-01-01
Full Text Available Abstract Background Since generic drugs have the same therapeutic effect as the original formulation but at generally lower costs, their use should be more heavily promoted. However, a considerable number of barriers to their wider use have been observed in many countries. The present study examines the influence of patients, physicians and certain characteristics of the generics' market on generic substitution in Switzerland. Methods We used reimbursement claims' data submitted to a large health insurer by insured individuals living in one of Switzerland's three linguistic regions during 2003. All dispensed drugs studied here were substitutable. The outcome (use of a generic or not was modelled by logistic regression, adjusted for patients' characteristics (gender, age, treatment complexity, substitution groups and with several variables describing reimbursement incentives (deductible, co-payments and the generics' market (prices, packaging, co-branded original, number of available generics, etc.. Results The overall generics' substitution rate for 173,212 dispensed prescriptions was 31%, though this varied considerably across cantons. Poor health status (older patients, complex treatments was associated with lower generic use. Higher rates were associated with higher out-of-pocket costs, greater price differences between the original and the generic, and with the number of generics on the market, while reformulation and repackaging were associated with lower rates. The substitution rate was 13% lower among hospital physicians. The adoption of the prescribing practices of the canton with the highest substitution rate would increase substitution in other cantons to as much as 26%. Conclusions Patient health status explained a part of the reluctance to substitute an original formulation by a generic. Economic incentives were efficient, but with a moderate global effect. The huge interregional differences indicated that prescribing behaviours and
Design and optimization of a material property distribution in a composite flywheel
Thielman, Scott Craig
The material properties of a fiber reinforced plastic laminate can be tailored for a given structure and loading by continuously varying the direction of the fiber through-out the plies. Here, it is shown that adding such a material property distribution to a thick-radius, composite flywheel can improve performance. A flywheel made from alternating plies of purely circumferential and purely radial reinforcement is designed as the performance benchmark. A second flywheel, substituting plies with a continuous fiber angle variation for the purely radial plies, is investigated. It is shown that the design of the fiber angle distribution can be formulated as an optimal control problem incorporating Classical Lamination Theory to describe the constitutive behavior and the Tsai-Wu failure criteria to predict failure of the flywheel laminate. The effects of the matrix properties on performance are also investigated. Numerical simulation indicates a 13% increase in energy density for the optimized flywheel over the benchmark flywheel. To demonstrate the feasibility of manufacture, automated ply layup machines are developed that are capable of producing the necessary carbon fiber plies. Experimentally determined material properties are used to re-run the optimization routine then prototype benchmark and optimized flywheel are constructed. Tangential strain measurements confirm that the separate flywheels have different material properties suggestive of those found in the analysis.
Directory of Open Access Journals (Sweden)
L. I. Rozonoer
1999-01-01
Full Text Available Necessary and sufficient conditions for existence of optimal control for all initial data are proved for LQ-optimization problem. If these conditions are fulfilled, necessary and sufficient conditions of optimality are formulated. Basing on the results, some general hypotheses on optimal control in terms of Pontryagin's maximum condition and Bellman's equation are proposed.
Substitution between cars within the household
DEFF Research Database (Denmark)
De Borger, Bruno; Mulalic, Ismir; Rouwendal, Jan
2016-01-01
.98 and 1.41 for the primary and secondary cars, respectively. Accounting for substitution effects, these figures reduce to, respectively, 0.32 and 0.45. Consistent with substitution behaviour, we find that the fuel price elasticity of fuel demand exceeds the elasticity of kilometre demands with respect...... to the fuel price; the difference strongly increases at the highest deciles of the distribution of kilometre demand. Extending the model to account for driver heterogeneity and the role of car characteristics confirmed the relevance of substitution between cars within the household. We found strong evidence......’ fuel efficiency choices are related to their price sensitivity....
Elasticity of Substitution and Antidumping Measures
DEFF Research Database (Denmark)
Drud Hansen, Jørgen; Meinen, Philipp; Nielsen, Jørgen Ulff-Møller
Abstract This paper analyzes the role of the elasticity of substitution for anti-dumping decisions across countries. In monopolistic competition models with cost heterogeneous firms across countries, price differences vary inversely with the elasticity of substitution. Anti-dumping duties should...... therefore also vary inversely with the elasticity of substitution at least for countries which have a strong focus on prices in the determination of their anti-dumping measures. We test this for ten countries from 1990 to 2009 using data on anti-dumping from Chad Bown (2010) and US-data at 8-digit level...