Understanding the Evolution and Stability of the G-Matrix
Arnold, Stevan J.; Bürger, Reinhard; Hohenlohe, Paul A.; Ajie, Beverley C.; Jones, Adam G.
2011-01-01
The G-matrix summarizes the inheritance of multiple, phenotypic traits. The stability and evolution of this matrix are important issues because they affect our ability to predict how the phenotypic traits evolve by selection and drift. Despite the centrality of these issues, comparative, experimental, and analytical approaches to understanding the stability and evolution of the G-matrix have met with limited success. Nevertheless, empirical studies often find that certain structural features of the matrix are remarkably constant, suggesting that persistent selection regimes or other factors promote stability. On the theoretical side, no one has been able to derive equations that would relate stability of the G-matrix to selection regimes, population size, migration, or to the details of genetic architecture. Recent simulation studies of evolving G-matrices offer solutions to some of these problems, as well as a deeper, synthetic understanding of both the G-matrix and adaptive radiations. PMID:18973631
Environmental effects on the structure of the G-matrix.
Wood, Corlett W; Brodie, Edmund D
2015-11-01
Genetic correlations between traits determine the multivariate response to selection in the short term, and thereby play a causal role in evolutionary change. Although individual studies have documented environmentally induced changes in genetic correlations, the nature and extent of environmental effects on multivariate genetic architecture across species and environments remain largely uncharacterized. We reviewed the literature for estimates of the genetic variance-covariance (G) matrix in multiple environments, and compared differences in G between environments to the divergence in G between conspecific populations (measured in a common garden). We found that the predicted evolutionary trajectory differed as strongly between environments as it did between populations. Between-environment differences in the underlying structure of G (total genetic variance and the relative magnitude and orientation of genetic correlations) were equal to or greater than between-population differences. Neither environmental novelty, nor the difference in mean phenotype predicted these differences in G. Our results suggest that environmental effects on multivariate genetic architecture may be comparable to the divergence that accumulates over dozens or hundreds of generations between populations. We outline avenues of future research to address the limitations of existing data and characterize the extent to which lability in genetic correlations shapes evolution in changing environments.
The susceptibility effect of matrix material on the g value of any radical.
Ucun, Fatih
2008-12-15
The susceptibility effect of matrix material on g value of any radical has theoretically been investigated. An equation which yields the relationship between the g value of radical and the magnetic susceptibility of matrix material has been deduced. Based on this equation, it has been concluded that if the matrix material is paramagnetic the g value of the radical becomes smaller than the g value of the same radical in vacuum while it becomes higher if the matrix material is diamagnetic. These statements have been found to be in good agreement with the experimental results.
G. Einstein matrix and nano-biophotonic treatment
NASA Astrophysics Data System (ADS)
Przybyl-Einstein, George; Moratin, Holdy; Garcia, Eduardo
2005-04-01
The publication is presenting the Einstein Matrix Treatment Method and initial results for blood borne diseases on example of hepatitis, HIV and arthritis. The initial research was conducted at Einstein Clinical Laboratories S.A. on limited funds. The treatment and method is strongly recommended for specific viruses bacteria in blood borne diseases but also for treatment of none specific viruses and bacteria in emergency treatments as SARS or ANTHRAX to safe life of the human. In the past years the Individual's Safety is in jeopardy by natural viral infections as well as by engineering cultured viruses and bacteria. Viruses mutate and become more resistant to current known medical treatment, in many cases partially efficient. This event required new testing method to investigate the possibility of treatments and to create new vaccine for non-specific viral and bacteria or viruses infections that causes death to thousands adults and children. The authors present in this paper the possibility of treatment of the non-specific viral, bacterial infections of the blood in human body. This treatment has safe procedure and no known side effect up to this time for patients that were treated at Einstein Clinical Laboratories SA.
Yu, Shan; Su, Tiantian; Wu, Huijun; Liu, Shiheng; Wang, Di; Zhao, Tianhu; Jin, Zengjun; Du, Wenbin; Zhu, Mei-Jun; Chua, Song Lin; Yang, Liang; Zhu, Deyu; Gu, Lichuan; Ma, Luyan Z
2015-01-01
Biofilms are surface-associated communities of microorganism embedded in extracellular matrix. Exopolysaccharide is a critical component in the extracellular matrix that maintains biofilm architecture and protects resident biofilm bacteria from antimicrobials and host immune attack. However, self-produced factors that target the matrix exopolysaccharides, are still poorly understood. Here, we show that PslG, a protein involved in the synthesis of a key biofilm matrix exopolysaccharide Psl in Pseudomonas aeruginosa, prevents biofilm formation and disassembles existing biofilms within minutes at nanomolar concentrations when supplied exogenously. The crystal structure of PslG indicates the typical features of an endoglycosidase. PslG mainly disrupts the Psl matrix to disperse bacteria from biofilms. PslG treatment markedly enhances biofilm sensitivity to antibiotics and macrophage cells, resulting in improved biofilm clearance in a mouse implant infection model. Furthermore, PslG shows biofilm inhibition and disassembly activity against a wide range of Pseudomonas species, indicating its great potential in combating biofilm-related complications. PMID:26611635
Population differentiation in G matrix structure due to natural selection in Rana temporaria.
Cano, José Manuel; Laurila, Anssi; Pało, Jukka; Merilä, Juha
2004-09-01
The additive genetic variance-covariance matrix (G) is a concept central to discussions about evolutionary change over time in a suite of traits. However, at the moment we do not know how fast G itself changes as a consequence of selection or how sensitive it is to environmental influences. We investigated possible evolutionary divergence and environmental influences on G using data from a factorial common-garden experiment where common frog (Rana temporaria) tadpoles from two divergent populations were exposed to three different environmental treatments. G-matrices were estimated using an animal model approach applied to data from a NCII breeding design. Matrix comparisons using both Flury and multivariate analysis of variance methods revealed significant differences in G matrices both between populations and between treatments within populations, the former being generally larger than the latter. Comparison of levels of population differentiation in trait means using Q(ST) indices with that observed in microsatellite markers (F(ST)) revealed that the former values generally exceeded the neutral expectation set by F(ST). Hence, the results suggest that intraspecific divergence in G matrix structure has occurred mainly due to natural selection.
Contribution of chromosomal polymorphisms to the G-matrix of Mimulus guttatus.
Scoville, Alison; Lee, Young Wha; Willis, John H; Kelly, John K
2009-08-01
Evolution of genetic (co)variances (the G-matrix) fundamentally influences multitrait divergence. Here, we isolated the contribution of two chromosomal quantitative trait loci (QTLs), a meiotic drive locus and a polymorphic inversion, to the overall G-matrix for a suite of floral, phenological and male fitness traits in a population of Mimulus guttatus. This allowed us to predict the evolution of trait means and genetic (co)variances as a function of allele frequencies, and to evaluate theories about the maintenance of genetic variation in fitness. Individuals generated using a replicated F(2) breeding design were grown under common conditions, genotyped and measured for trait values. Significant additive genetic variance existed for all traits, and most genetic covariances were significantly nonzero. Both QTLs contribute to the additive genetic (co)variances of multiple traits. Pleiotropy was not generally consistent, either between QTLs or with the genetic background. Shifts in allele frequencies at either QTL are predicted to result in substantial changes in the G-matrix. Both QTLs contribute substantially to the genetic variation in pollen viability. The Drive QTL, and perhaps also the inversion, demonstrates the contribution of balancing selection to the maintenance of genetic variation in fitness.
Similarity in G matrix structure among natural populations of Arabidopsis lyrata.
Puentes, Adriana; Granath, Gustaf; Ågren, Jon
2016-10-01
Understanding the stability of the G matrix in natural populations is fundamental for predicting evolutionary trajectories; yet, the extent of its spatial variation and how this impacts responses to selection remain open questions. With a nested paternal half-sib crossing design and plants grown in a field experiment, we examined differences in the genetic architecture of flowering time, floral display, and plant size among four Scandinavian populations of Arabidopsis lyrata. Using a multivariate Bayesian framework, we compared the size, shape, and orientation of G matrices and assessed their potential to facilitate or constrain trait evolution. Flowering time, floral display and rosette size varied among populations and significant additive genetic variation within populations indicated potential to evolve in response to selection. Yet, some characters, including flowering start and number of flowers, may not evolve independently because of genetic correlations. Using a multivariate framework, we found few differences in the genetic architecture of traits among populations. G matrices varied mostly in size rather than shape or orientation. Differences in multivariate responses to selection predicted from differences in G were small, suggesting overall matrix similarity and shared constraints to trait evolution among populations. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.
Rapid and unpredictable changes of the G-matrix in a natural bird population over 25 years.
Björklund, M; Husby, A; Gustafsson, L
2013-01-01
Knowledge of the genetic variances and covariances of traits (the G-matrix) is fundamental for the understanding of evolutionary dynamics of populations. Despite its essential importance in evolutionary studies, empirical tests of the temporal stability of the G-matrix in natural populations are few. We used a 25-year-long individual-based field study on almost 7000 breeding attempts of the collared flycatcher (Ficedula albicollis) to estimate the stability of the G-matrix over time. Using animal models to estimate G for several time periods, we show that the structure of the time-specific G-matrices changed significantly over time. The temporal changes in the G-matrix were unpredictable, and the structure at one time period was not indicative of the structure at the next time period. Moreover, we show that the changes in the time-specific G-matrices were not related to changes in mean trait values or due to genetic drift. Selection, differences in acquisition/allocation patterns or environment-dependent allelic effects are therefore likely explanations for the patterns observed, probably in combination. Our result cautions against assuming constancy of the G-matrix and indicates that even short-term evolutionary predictions in natural populations can be very challenging. © 2012 The Authors. Journal of Evolutionary Biology © 2012 European Society For Evolutionary Biology.
Cauchy-Laguerre Two-Matrix Model and the Meijer-G Random Point Field
NASA Astrophysics Data System (ADS)
Bertola, M.; Gekhtman, M.; Szmigielski, J.
2014-02-01
We apply the general theory of Cauchy biorthogonal polynomials developed in Bertola et al. (Commun Math Phys 287(3):983-1014, 2009) and Bertola et al. (J Approx Th 162(4):832-867, 2010) to the case associated with Laguerre measures. In particular, we obtain explicit formulae in terms of Meijer-G functions for all key objects relevant to the study of the corresponding biorthogonal polynomials and the Cauchy two-matrix model associated with them. The central theorem we prove is that a scaling limit of the correlation functions for eigenvalues near the origin exists, and is given by a new determinantal two-level random point field, the Meijer-G random field. We conjecture that this random point field leads to a novel universality class of random fields parametrized by exponents of Laguerre weights. We express the joint distributions of the smallest eigenvalues in terms of suitable Fredholm determinants and evaluate them numerically. We also show that in a suitable limit, the Meijer-G random field converges to the Bessel random field and hence the behavior of the eigenvalues of one of the two matrices converges to the one of the Laguerre ensemble.
Gmat. A software tool for the computation of the rovibrational G matrix
NASA Astrophysics Data System (ADS)
Castro, M. E.; Niño, A.; Muñoz-Caro, C.
2009-07-01
Gmat is a C++ program able to compute the rovibrational G matrix in molecules of arbitrary size. This allows the building of arbitrary rovibrational Hamiltonians. In particular, the program is designed to work with the structural results of potential energy hypersurface mappings computed in computer clusters or computational Grid environments. In the present version, 1.0, the program uses internal coordinates as vibrational coordinates, with the principal axes of inertia as body-fixed system. The main design implements a complete separation of the interface and functional parts of the program. The interface part permits the automatic reading of the molecular structures from the output files of different electronic structure codes. At present, Gamess and Gaussian output files are allowed. To such an end, use is made of the object orientation polymorphism characteristic. The functional part computes numerically the derivatives of the nuclear positions respect to the vibrational coordinates. Very accurate derivatives are obtained by using central differences embedded in a nine levels Richardson extrapolation procedure. Program summaryProgram title: Gmat Catalogue identifier: AECZ_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AECZ_v1_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.: 17 023 No. of bytes in distributed program, including test data, etc.: 274 714 Distribution format: tar.gz Programming language: Standard C++ Computer: All running Linux/Windows Operating system: Linux, Windows Classification: 16.2 Nature of problem: Computation of the rovibrational G matrix in molecules of any size. This allows the building of arbitrary rovibrational Hamiltonians. It must be possible to obtain the input data from the output files of standard electronic structure codes
Sen, Gautam; Pal, Sagar
2009-07-01
This paper reports the investigation of microwave initiated synthesized polyacrylamide grafted carboxymethylstarch (CMS-g-PAM) as matrix for sustained drug release. 'In vitro' release of a model drug (5-amino salicylic acid) from CMS-g-PAM matrix has been studied. It is evident that higher the percentage grafting, more sustained is the rate of drug release. Further, the percentage grafting vs. t(50) value (i.e. time taken for release of 50% of the enclosed drug) correlation has been successfully studied for the first time. This correlation will lead to the possibility of a programmable drug release matrix based on grafted polysaccharide. In this matrix, the rate of release of the enclosed drug can be precisely programmed simply by adjustment of percentage grafting during synthesis.
Rapid Communication with a “P300” Matrix Speller Using Electrocorticographic Signals (ECoG)
Brunner, Peter; Ritaccio, Anthony L.; Emrich, Joseph F.; Bischof, Horst; Schalk, Gerwin
2010-01-01
A brain–computer interface (BCI) can provide a non-muscular communication channel to severely disabled people. One particular realization of a BCI is the P300 matrix speller that was originally described by Farwell and Donchin (1988). This speller uses event-related potentials (ERPs) that include the P300 ERP. All previous online studies of the P300 matrix speller used scalp-recorded electroencephalography (EEG) and were limited in their communication performance to only a few characters per minute. In our study, we investigated the feasibility of using electrocorticographic (ECoG) signals for online operation of the matrix speller, and determined associated spelling rates. We used the matrix speller that is implemented in the BCI2000 system. This speller used ECoG signals that were recorded from frontal, parietal, and occipital areas in one subject. This subject spelled a total of 444 characters in online experiments. The results showed that the subject sustained a rate of 17 characters/min (i.e., 69 bits/min), and achieved a peak rate of 22 characters/min (i.e., 113 bits/min). Detailed analysis of the results suggests that ERPs over visual areas (i.e., visual evoked potentials) contribute significantly to the performance of the matrix speller BCI system. Our results also point to potential reasons for the apparent advantages in spelling performance of ECoG compared to EEG. Thus, with additional verification in more subjects, these results may further extend the communication options for people with serious neuromuscular disabilities. PMID:21369351
NASA Astrophysics Data System (ADS)
Roemelt, Michael
2015-07-01
Spin Orbit Coupling (SOC) is introduced to molecular ab initio density matrix renormalization group (DMRG) calculations. In the presented scheme, one first approximates the electronic ground state and a number of excited states of the Born-Oppenheimer (BO) Hamiltonian with the aid of the DMRG algorithm. Owing to the spin-adaptation of the algorithm, the total spin S is a good quantum number for these states. After the non-relativistic DMRG calculation is finished, all magnetic sublevels of the calculated states are constructed explicitly, and the SOC operator is expanded in the resulting basis. To this end, spin orbit coupled energies and wavefunctions are obtained as eigenvalues and eigenfunctions of the full Hamiltonian matrix which is composed of the SOC operator matrix and the BO Hamiltonian matrix. This treatment corresponds to a quasi-degenerate perturbation theory approach and can be regarded as the molecular equivalent to atomic Russell-Saunders coupling. For the evaluation of SOC matrix elements, the full Breit-Pauli SOC Hamiltonian is approximated by the widely used spin-orbit mean field operator. This operator allows for an efficient use of the second quantized triplet replacement operators that are readily generated during the non-relativistic DMRG algorithm, together with the Wigner-Eckart theorem. With a set of spin-orbit coupled wavefunctions at hand, the molecular g-tensors are calculated following the scheme proposed by Gerloch and McMeeking. It interprets the effective molecular g-values as the slope of the energy difference between the lowest Kramers pair with respect to the strength of the applied magnetic field. Test calculations on a chemically relevant Mo complex demonstrate the capabilities of the presented method.
Roemelt, Michael
2015-07-28
Spin Orbit Coupling (SOC) is introduced to molecular ab initio density matrix renormalization group (DMRG) calculations. In the presented scheme, one first approximates the electronic ground state and a number of excited states of the Born-Oppenheimer (BO) Hamiltonian with the aid of the DMRG algorithm. Owing to the spin-adaptation of the algorithm, the total spin S is a good quantum number for these states. After the non-relativistic DMRG calculation is finished, all magnetic sublevels of the calculated states are constructed explicitly, and the SOC operator is expanded in the resulting basis. To this end, spin orbit coupled energies and wavefunctions are obtained as eigenvalues and eigenfunctions of the full Hamiltonian matrix which is composed of the SOC operator matrix and the BO Hamiltonian matrix. This treatment corresponds to a quasi-degenerate perturbation theory approach and can be regarded as the molecular equivalent to atomic Russell-Saunders coupling. For the evaluation of SOC matrix elements, the full Breit-Pauli SOC Hamiltonian is approximated by the widely used spin-orbit mean field operator. This operator allows for an efficient use of the second quantized triplet replacement operators that are readily generated during the non-relativistic DMRG algorithm, together with the Wigner-Eckart theorem. With a set of spin-orbit coupled wavefunctions at hand, the molecular g-tensors are calculated following the scheme proposed by Gerloch and McMeeking. It interprets the effective molecular g-values as the slope of the energy difference between the lowest Kramers pair with respect to the strength of the applied magnetic field. Test calculations on a chemically relevant Mo complex demonstrate the capabilities of the presented method.
Ramos-Clamont, Gabriela; del Carmen Candia-Plata, Maria; Zamudio, Roberto Guzman; Vazquez-Moreno, Luz
2006-07-28
A new, highly acetylated agarose matrix (HA-Sepharose) was synthesized and used as a hydrophobic interaction chromatography (HIC) medium to specifically isolate immunoglobulins (Igs) from porcine serum. Recovery of Igs was in a single step and under mild conditions. HA-Sepharose adsorption was studied in terms of salt, gel acetylation time, flow rate, and protein concentration on the loading buffer. At 0.5 M Na2SO4, control with unmodified Sepharose retained a small fraction (0.70 mg/mL of matrix) of serum albumin. On the contrary HA-Sepharose retained primary Igs (IgA, IgG, and 53% of IgM) as revealed by sodium dodecyl sulphate 10% polyacrylamide gel electrophoresis (SDS-PAGE), quantitative radial immunodiffusion and immunodetection. At a flow rate of 1 mL/min, the HA-Sepharose column capacity (3.9 mg/mL of matrix) was similar to the reported capacity for the commercial thiophilic T-gel. However, HA-Sepharose showed higher recovery of IgA and IgM than the T-gel in the same salt conditions, clearly an advantage in terms of immunoglobulin recovery strategies. Acetylation changed the matrix adsorption from albumin to immunoglobulins; thus, the highly acetylated gel rendered recoveries of Igs from unprocessed porcine serum practically free of albumin.
Eck, Sarah M; Blackburn, Jessica S; Schmucker, Adam C; Burrage, Peter S; Brinckerhoff, Constance E
2009-01-01
Similarities in the pathologies of autoimmune diseases and cancer have been noted for at least 30 years. Inflammatory cytokines and growth factors mediate cell proliferation, and proteinases, especially the collagenase, Matrix Metalloproteinase-1 (MMP-1), contribute to disease progression by remodeling the extracellular matrix and modulating the microenvironment. This review focuses on two cancers (melanoma and breast) and on the autoimmune disorder, rheumatoid arthritis (RA), and discusses the activated stromal cells found in these diseases. MMP-1 was originally thought to function only to degrade interstitial collagens, but recent studies have revealed novel roles for MMP-1 involving the G protein-coupled receptors: the chemokine receptor, CXCR-4, and Protease Activated Receptor-1 (PAR-1). Cooperativity between MMP-1 and CXCR4/SDF-1 signaling influences the behavior of activated fibroblasts in both RA and cancer. Further, MMP-1 is a vital part of an autocrine/paracrine MMP-1/PAR-1 signal transduction axis, a function that amplifies its potential to remodel the matrix and to modify cell behavior. Finally, new therapeutic agents directed at MMP-1 and G protein-coupled receptors are emerging. Even though these agents are more specific in their targets than past therapies, these targets are often shared between RA and cancer, underscoring fundamental similarities between autoimmune disorders and some cancers.
Eck, Sarah M.; Blackburn, Jessica S.; Schmucker, Adam C.; Burrage, Peter S.; Brinckerhoff, Constance E.
2009-01-01
Similarities in the pathologies of autoimmune diseases and cancer have been noted for at least 30 years. Inflammatory cytokines and growth factors mediate cell proliferation, and proteinases, especially the collagenase, Matrix Metalloproteinase-1 (MMP-1), contribute to disease progression by remodeling the extracellular matrix and modulating the microenvironment. This review focuses on two cancers (melanoma and breast) and on the autoimmune disorder, rheumatoid arthritis (RA), and discusses the activated stromal cells found in these diseases. MMP-1 was originally thought to function only to degrade interstitial collagens, but recent studies have revealed novel roles for MMP-1 involving the G protein-coupled receptors: the chemokine receptor, CXCR-4, and Protease Activated Receptor-1 (PAR-1). Cooperativity between MMP-1 and CXCR4/SDF-1 signaling influences the behavior of activated fibroblasts in both RA and cancer. Further, MMP-1 is a vital part of an autocrine/paracrine MMP-1/PAR-1 signal transduction axis, a function that amplifies its potential to remodel the matrix and to modify cell behavior. Finally, new therapeutic agents directed at MMP-1 and G protein-coupled receptors are emerging. Even though these agents are more specific in their targets than past therapies, these targets are often shared between RA and cancer, underscoring fundamental similarities between autoimmune disorders and some cancers. PMID:19800199
Martin, Guillaume; Chapuis, Elodie; Goudet, Jérôme
2008-12-01
Neutrality tests in quantitative genetics provide a statistical framework for the detection of selection on polygenic traits in wild populations. However, the existing method based on comparisons of divergence at neutral markers and quantitative traits (Q(st)-F(st)) suffers from several limitations that hinder a clear interpretation of the results with typical empirical designs. In this article, we propose a multivariate extension of this neutrality test based on empirical estimates of the among-populations (D) and within-populations (G) covariance matrices by MANOVA. A simple pattern is expected under neutrality: D = 2F(st)/(1 - F(st))G, so that neutrality implies both proportionality of the two matrices and a specific value of the proportionality coefficient. This pattern is tested using Flury's framework for matrix comparison [common principal-component (CPC) analysis], a well-known tool in G matrix evolution studies. We show the importance of using a Bartlett adjustment of the test for the small sample sizes typically found in empirical studies. We propose a dual test: (i) that the proportionality coefficient is not different from its neutral expectation [2F(st)/(1 - F(st))] and (ii) that the MANOVA estimates of mean square matrices between and among populations are proportional. These two tests combined provide a more stringent test for neutrality than the classic Q(st)-F(st) comparison and avoid several statistical problems. Extensive simulations of realistic empirical designs suggest that these tests correctly detect the expected pattern under neutrality and have enough power to efficiently detect mild to strong selection (homogeneous, heterogeneous, or mixed) when it is occurring on a set of traits. This method also provides a rigorous and quantitative framework for disentangling the effects of different selection regimes and of drift on the evolution of the G matrix. We discuss practical requirements for the proper application of our test in empirical
Martin, Guillaume; Chapuis, Elodie; Goudet, Jérôme
2008-01-01
Neutrality tests in quantitative genetics provide a statistical framework for the detection of selection on polygenic traits in wild populations. However, the existing method based on comparisons of divergence at neutral markers and quantitative traits (Qst–Fst) suffers from several limitations that hinder a clear interpretation of the results with typical empirical designs. In this article, we propose a multivariate extension of this neutrality test based on empirical estimates of the among-populations (D) and within-populations (G) covariance matrices by MANOVA. A simple pattern is expected under neutrality: D = 2Fst/(1 − Fst)G, so that neutrality implies both proportionality of the two matrices and a specific value of the proportionality coefficient. This pattern is tested using Flury's framework for matrix comparison [common principal-component (CPC) analysis], a well-known tool in G matrix evolution studies. We show the importance of using a Bartlett adjustment of the test for the small sample sizes typically found in empirical studies. We propose a dual test: (i) that the proportionality coefficient is not different from its neutral expectation [2Fst/(1 − Fst)] and (ii) that the MANOVA estimates of mean square matrices between and among populations are proportional. These two tests combined provide a more stringent test for neutrality than the classic Qst–Fst comparison and avoid several statistical problems. Extensive simulations of realistic empirical designs suggest that these tests correctly detect the expected pattern under neutrality and have enough power to efficiently detect mild to strong selection (homogeneous, heterogeneous, or mixed) when it is occurring on a set of traits. This method also provides a rigorous and quantitative framework for disentangling the effects of different selection regimes and of drift on the evolution of the G matrix. We discuss practical requirements for the proper application of our test in empirical studies and
[Calcification marker matrix G1a protein in patients with hyperlipidemia].
Kullich, Werner; Machreich, Kurt; Hawa, Gerhard; Eichinger, Brigitte; Klein, Gert
2003-01-01
At the site of atherosclerotic plaque formation, proliferating vascular muscle cells express Matrix-Gla-protein (MGP) which depends on vitamin K and plays a regulatory role in tissue calcification. Measurements of MGP in serum showed significantly higher values in 66 patients with hyperlipidemia compared to healthy controls. MGP correlated with cholesterol, triglyceride, and low-density lipoprotein, but not with the adhesion molecule GMP-140. The evaluation of the patients' life and nutritional habits showed that nearly exclusively the patients who regularly consume fruit had low MGP values. Smokers had high MGP levels, three times higher than non-smokers. A decrease in MGP levels could be shown already three weeks after inpatient rehabilitation comprising therapeutic exercise and change in nutrition.
Heuristic computation of the rovibrational G matrix in optimized molecule-fixed axes. Gmat 2.1
NASA Astrophysics Data System (ADS)
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
Jones, Adam G.; Bürger, Reinhard; Arnold, Stevan J.; Hohenlohe, Paul A.; Uyeda, Josef C.
2012-01-01
Theoretical and empirical results demonstrate that the G-matrix, which summarizes additive genetic variances and covariances of quantitative traits, changes over time. Such evolution and fluctuation of the G-matrix could potentially have wide-ranging effects on phenotypic evolution. Nevertheless, no studies have yet addressed G-matrix stability and evolution when movement of an intermediate optimum includes large, episodic jumps or stochasticity. Here, we investigate such scenarios by using simulation-based models of G-matrix evolution. These analyses yield four important insights regarding the evolution and stability of the G-matrix. (1) Regardless of the model of peak movement, a moving optimum causes the G-matrix to orient toward the direction of net peak movement, so that genetic variance is enhanced in that direction (the variance enhancement effect). (2) Peak movement skews the distribution of breeding values in the direction of movement, which impedes the response to selection. (3) The stability of the G-matrix is affected by the overall magnitude and direction of peak movement, but modes and rates of peak movement have surprisingly small effects (the invariance principle). (4) Both episodic and stochastic peak movement increase the probability that a population will fall below its carrying capacity and go extinct. We also present novel equations for the response of the trait mean to multivariate selection that take into account the higher moments of the distribution of breeding values. PMID:22957960
Akbulut, Huseyin; Bozokalfa, Guliz; Asker, Duygu N; Demir, Bilal; Guler, Emine; Odaci Demirkol, Dilek; Timur, Suna; Yagci, Yusuf
2015-09-23
In the ever-expanding field of conducting polymer research, functionalized graft hybrid copolymers have gained considerable interest in the biomedical engineering and biosensing applications, particularly. In the present work, a new biosensor based on conducting graft copolymer for the detection of phenolic compounds was developed. Thereby, a robust and novel material, namely "polythiophene-g-poly(ethylene glycol) with lateral amino groups" (PT-NH2-g-PEG) hybrid conducting polymer was synthesized via Suzuki condensation polymerization and characterized with (1)H NMR analysis, UV-vis spectroscopy, gel permeation chromatography (GPC) and fluorescence spectroscopy. PT-NH2-g-PEG architecture was then applied as an immobilization matrix to accomplish extended biosensing function. In a typical process, Laccase was utilized as a model enzyme for the detection of phenolic compounds. Detailed surface characterization of PT-NH2-g-PEG/Lac was performed by cyclic voltammetry, electrochemical impedance spectroscopy, atomic force microscopy, fluorescence microscopy and scanning electron microscopy measurements. Optimum pH and polymer amount were found to be pH 6.5 and 0.5 mg polymer, respectively, with the linear range of 0.0025-0.05 mM and 132.45 μA/mM sensitivity. The kinetic parameters of PT-NH2-g-PEG/Lac are 0.026 mM for Km(app) and 7.38 μA for Imax, respectively. Furthermore, the PT-NH2-g-PEG/Lac biofilm was retained 82% of its activity for 12 days indicating excellent recovery as tested with artificial wastewater.
Byers, F.M. Jr.
1985-12-01
This study describes and interprets petrochemical variation of the matrix (excluding fractures and large gas cavities) of the Topopah Spring Member of the Paintbrush Tuff. This tuff includes the candidate host rock for a high-level nuclear waste repository at Yucca Mountain on the Nevada Test Site. Cored hole USW G-4, near the site of a potential exploratory shaft at Yucca Mountain, penetrated 359.4 m (1179 ft) of the member within the unsaturated zone. This study shows that petrographic textures and chemistry of the matrix vary systematically within recognizable lithologic subunits related to crystallization (cooling) zones, welding (compaction) zones, and compositional zones (rhyolite versus quartz latite). The methods used for this study include petrographic modal thin section analysis using an automated counter and electron microprobe analysis of the groundmass. Distinctive textural categories are defined, and they can be ranked from finest to coarsest as vitrophyre (glass), cryptocrystalline groundmass, spherulites, granophyre, lithic fragments, and phenocrysts. The two main groundmass compositions are also defined: rhyolite high silica) and quartz latite. The value of these petrochemical studies lies in providing microscopic criteria for recognizing the zonal subunits where they may have greatly limited exposure, as in mined drifts and in core from horizontal drill holes. For example, the lower nonlithophysal zone can be distinguished microscopically from the middle nonlithophysal zone by (1) degree of compaction, (2) amount of quartz, and (3) amount of lithic fragments. The variability between these textural categories should also be considered in designing physical and chemical tests of the Topopah Spring.
Marschall, Z von; Riecken, E-O; Rosewicz, S
1999-01-01
We have investigated the effects of retinoic acid (RA) on matrix metalloprotease-1 (MMP-1) gene expression in the human pancreatic tumour cell line Dan-G. 13-cis RA results in a time- and dose-dependent increase of MMP-1 protein concentration. These stimulatory effects were paralleled by a time- and dose-dependent increase of MMP-1 mRNA steady-state concentrations. Nuclear run-on analysis revealed that the increase of MMP-1 mRNA was partially due to an increase of MMP-1 gene transcription. In addition, 13-cis RA treatment results in an increase of MMP-1 mRNA stability. These data demonstrate that RA stimulates MMP-1 gene expression in human pancreatic carcinoma cells by transcriptional and post-transcriptional mechanisms. © 1999 Cancer Research Campaign PMID:10362099
Fayed, Mohamed H; Mahrous, Gamal M; Ibrahim, Mohamed A; Sakr, Adel
2013-01-01
The objective of this study was to evaluate the potential of Carbopol(®) 71G-NF on the release of dextromethorphan hydrobromide (DM) from matrix tablets in comparison with hydroxypropyl methylcellulose (HPMC(®) K15M) and Eudragit(®) L100-55 polymers. Controlled release DM matrix tablets were prepared using Carbopol 71G-NF, HPMC K15M, and Eudragit L100-55 at different drug to polymer ratios by direct compression technique. The mechanical properties of the tablets as tested by crushing strength and friability tests were improved as the concentration of Carbopol, HPMC, and Eudragit increased. However, Carbopol-based tablets showed a significantly (P<0.05) higher crushing strength and a lower friability than HPMC and Eudragit tablets. No significant differences in weight uniformity and thickness values were observed between the different formulations. It was also found that Carbopol significantly (P<0.05) delayed the release of DM in comparison with HPMC K15M and Eudragit L100-55. A combination of HPMC K15M and Eudragit L100-55 in a 1:1 ratio at 20 and 30% significantly (P<0.05) delayed the release of DM than Eudragit L100-55 alone. Moreover, blends of Carbopol and HPMC at a 1:1 ratio at the 10, 20, and 30% total polymer concentration were investigated. The blend of Carbopol and HPMC at 10% level significantly (P<0.05) slowed the release of DM than Carbopol or HPMC alone, whereas blends at 20 and 30% level significantly (P<0.05) delayed the release of DM compared with HPMC or Carbopol alone. The results with these polymer blends showed that it was possible to reduce the total amount of polymers when used as a combination in formulation.
Han, Guoda; Wei, Zhijiang; Lu, Zhiliang; Cui, Haibin; Bai, Xiyong; Ge, Huai'e; Zhang, Wei
2014-01-01
The association between MMP1 -1607 1G>2G polymorphism and cancer risk has been reported, but results remained controversial and ambiguous. To assess the association between MMP1 -1607 1G>2G polymorphism and cancer risk, a meta-analysis was performed. Based on comprehensive searches of the PubMed, Elsevier Science Direct, Excerpta Medica Database (Embase), and Chinese Biomedical Literature Database (CBM), we identified outcome data from all articles estimating the association between MMP1 -1607 1G>2G polymorphism and cancer risk. The pooled odds ratio (OR) with 95% confidence intervals (CIs) were calculated. Thirty-eight studies involving 10178 cases and 9528 controls were included. Overall, significant association between MMP1 -1607 1G>2G polymorphism and cancer susceptibility was observed for additive model (OR = 1.21, 95% CI 1.09-1.35), for codominant model (OR = 1.34, 95% CI 1.10-1.63), for dominant model (OR = 1.17, 95% CI 1.01-1.34), for recessive model (OR = 1.31, 95% CI 1.14-1.52). In the subgroup analysis by ethnicity, the significant association was found among Asians but not among Caucasians. In the subgroup analysis by site of cancer, significant associations were found among lung cancer, colorectal cancer, head and neck cancer and bladder cancer. This meta-analysis demonstrated that the MMP1 -1607 1G>2G polymorphism was significantly associated with cancer risk.
Sri Manjari, K; Nallari, Pratibha; Balakrishna, N; Vidyasagar, A; Prabhakar, B; Jyothy, A; Venkateshwari, A
2013-08-01
This study investigated the role of -1607 (1G/2G) (rs1799750) polymorphism of the MMP-1 gene in chronic pancreatitis. We genotyped 100 patients with chronic pancreatitis and 100 control subjects using tetra-primer ARMS-PCR followed by agarose gel electrophoresis. Serum levels of MMP-1 were determined by Elisa. Statistical analysis was applied to test the significance of the results. The genotypic and allelic distribution varied significantly between the disease group and the control subjects [OD = 1.981 (1.236-3.181), p = 0.004]. MMP-1 levels were higher in subjects homozygous for the 2G allele than in subjects with the 1G allele. The present study revealed a significant association of the MMP-1 -1607 1G/2G (rs1799750) gene promoter polymorphism with chronic pancreatitis, and it can be considered a biological marker in the etiology of chronic pancreatitis.
NASA Astrophysics Data System (ADS)
Hilbig, Reinhard; Hendrik Anken, Ralf; Weigele, Jochen
The results of the Foton-M3 mission (OmegaHab) give evidence that the otoliths of the fish form OmegaHab were larger as compared to the ground control. Additionally the shape (raphe) and morphology especially the mode of crystallization of the otoliths were affected during growth in weightlessness. The reason for these changes is assumed to originate from changes in the composition of the otolith matrix and Ca-binding proteins (OMP). The OMPs play an important role in controlling the crystallization process and additionally the morphology of crystals, determining the crystallpolymorph and the strength of the crystals. The matrix of otoliths is a complex functional structure containing several calcium-binding proteins, structural proteins and protease inhibitors. Furthermore it is composed of otolith matrix protein-1, Otolin, Otoconin, SPARC and Neuroserpin, which is a specific expression in the otolth matrix for chichlid fish. During embryonic development of the fish inner ear, these proteins show a spacial and temporal expression pattern. The formation of the inner ear -including otoliths and sensory cells -starting from the otocyst-anlage -can be subdivided in several major developmental stages e.g. the forming of the otic cavity (stage 7/8), the tetha cell or seeding stage (stage 8, 9), the development of the semicircular channels (stage 12), the transition to further daily growth (post stage15) and the development of the third otolith, asteriscus (stage 23). These developmental phases contain different constitutions or involvements of matrix proteins. We investigated the matrixprotein composition of the chichlid fish Oreochromis mossambicus and found that the otolith matrix differentiate between other fishes. In this case some matrix proteins seem to be uniform in fishes, other known matrix proteins are lacking and we have also references to new candidates for matrix proteins chichlids. In this case we investigated the expression of the matrix proteins otolith
Chapuis, Elodie; Martin, Guillaume; Goudet, Jérôme
2008-12-01
Unraveling the effect of selection vs. drift on the evolution of quantitative traits is commonly achieved by one of two methods. Either one contrasts population differentiation estimates for genetic markers and quantitative traits (the Q(st)-F(st) contrast) or multivariate methods are used to study the covariance between sets of traits. In particular, many studies have focused on the genetic variance-covariance matrix (the G matrix). However, both drift and selection can cause changes in G. To understand their joint effects, we recently combined the two methods into a single test (accompanying article by Martin et al.), which we apply here to a network of 16 natural populations of the freshwater snail Galba truncatula. Using this new neutrality test, extended to hierarchical population structures, we studied the multivariate equivalent of the Q(st)-F(st) contrast for several life-history traits of G. truncatula. We found strong evidence of selection acting on multivariate phenotypes. Selection was homogeneous among populations within each habitat and heterogeneous between habitats. We found that the G matrices were relatively stable within each habitat, with proportionality between the among-populations (D) and the within-populations (G) covariance matrices. The effect of habitat heterogeneity is to break this proportionality because of selection for habitat-dependent optima. Individual-based simulations mimicking our empirical system confirmed that these patterns are expected under the selective regime inferred. We show that homogenizing selection can mimic some effect of drift on the G matrix (G and D almost proportional), but that incorporating information from molecular markers (multivariate Q(st)-F(st)) allows disentangling the two effects.
Pham, T. Anh; Nguyen, Huy -Viet; Rocca, Dario; Galli, Giulia
2013-04-26
In a recent paper we presented an approach to evaluate quasiparticle energies based on the spectral decomposition of the static dielectric matrix. This method does not require the calculation of unoccupied electronic states or the direct diagonalization of large dielectric matrices, and it avoids the use of plasmon-pole models. The numerical accuracy of the approach is controlled by a single parameter, i.e., the number of eigenvectors used in the spectral decomposition of the dielectric matrix. Here we present a comprehensive validation of the method, encompassing calculations of ionization potentials and electron affinities of various molecules and of band gaps for several crystalline and disordered semiconductors. Lastly, we demonstrate the efficiency of our approach by carrying out $GW$ calculations for systems with several hundred valence electrons.
NASA Astrophysics Data System (ADS)
Weeks, David E.; Niday, Thomas A.; Yang, Sang H.
2006-10-01
Inelastic scattering matrix elements for the nonadiabatic collision B(P1/22)+H2(Σg+1,j)↔B(P3/22)+H2(Σg+1,j') are calculated using the time dependent channel packet method (CPM). The calculation employs 1A'2, 2A'2, and 1A″2 adiabatic electronic potential energy surfaces determined by numerical computation at the multireference configuration-interaction level [M. H. Alexander, J. Chem. Phys. 99, 6041 (1993)]. The 1A'2 and 2A'2, adiabatic electronic potential energy surfaces are transformed to yield diabatic electronic potential energy surfaces that, when combined with the total B +H2 rotational kinetic energy, yield a set of effective potential energy surfaces [M. H. Alexander et al., J. Chem. Phys. 103, 7956 (1995)]. Within the framework of the CPM, the number of effective potential energy surfaces used for the scattering matrix calculation is then determined by the size of the angular momentum basis used as a representation. Twenty basis vectors are employed for these calculations, and the corresponding effective potential energy surfaces are identified in the asymptotic limit by the H2 rotor quantum numbers j =0, 2, 4, 6 and B electronic states Pja2, ja=1/2, 3/2. Scattering matrix elements are obtained from the Fourier transform of the correlation function between channel packets evolving in time on these effective potential energy surfaces. For these calculations the H2 bond length is constrained to a constant value of req=1.402a.u. and state to state scattering matrix elements corresponding to a total angular momentum of J =1/2 are discussed for j =0↔j'=0,2,4 and P1/22↔P1/22, P3/22 over a range of total energy between 0.0 and 0.01a.u.
NASA Technical Reports Server (NTRS)
Murri, G. B.; Obrien, T. K.
1985-01-01
The usefulness of the end-notched flexure (ENF) test for measuring G(IIc) for toughened composites was evaluated. Calculations were made using the measured flexural compliance from the ENF test and the measured axial modulus. Tests were conducted on three different composite materials, using laminates with two different span lengths and insert sizes. The error associated with neglecting nonlinear terms in the displacement-curvature relationship was analyzed to demonstrate the influence of specimen geometry on G(IIc) measurement. It is concluded that G(IIc) measurement may vary with the method of calculation, span length, or insert thickness, but these effects are minor compared to the large differences in measurements obtained for different materials. Hence, the ENF test is a valid one for screening materials for improvements in interlaminar shear fracture toughness.
Sá-Lima, Helena; Tuzlakoglu, Kadriye; Mano, João F; Reis, Rui L
2011-09-15
Recent advances in tissue engineering and regenerative medicine fields can offer alternative solutions to the existing techniques for cartilage repair. In this context, a variety of materials has been proposed, and the injectable hydrogels are among the most promising alternatives. The aim of this work is to explore the ability of poly(N-isopropylacrylamide)-g-methylcellulose (PNIPAAm-g-MC) thermoreversible hydrogel as a three-dimensional support for cell encapsulation toward the regeneration of articular cartilage through a tissue engineering approach. The PNIPAAm-g-MC copolymer was effectively obtained using ammonium-persulfate and N,N,N',N'-tetramethylethylenediamine as initiator as confirmed by Fourier transform infrared spectroscopy and (1) H NMR results. The copolymer showed to be temperature responsive, becoming a gel at temperatures above its lower critical solution temperature (~ 32 °C) while turning into a liquid below it. Results obtained from the MTS test showed that extracts of the hydrogel were clearly noncytotoxic to L929 fibroblast cells. ATDC5 cells, a murine chondrogenic cell line, were used as the in vitro model for this study; they were encapsulated at high cell density within the hydrogel and cultured for up to 28 days. PNIPAAm-g-MC did not affect the cell viability and proliferation, as indicated by both MTS and DNA assays. The results also revealed an increase in synthesis of glycosoaminoglycans within culture time measured by the dimethylmethylene blue quantification assay. These results suggest the viability of using PNIPAAm-g-MC thermoresponsive hydrogel as a three-dimensional scaffold for cartilage tissue engineering using minimal-invasive strategies. Copyright © 2011 Wiley Periodicals, Inc.
Chenoweth, Stephen F; Blows, Mark W
2008-06-01
The Q(ST)-F(ST) comparison has become an increasingly common method for inferring adaptive quantitative trait divergence among populations. For cases in which there is divergence in multiple traits, most studies have applied the method by performing multiple univariate Q(ST)-F(ST) comparisons. However, because traits are often genetically correlated, such univariate analyses are likely to paint a simplified picture of adaptive divergence. Here we show how the multivariate analogue of Q(ST), F(STq), which accounts for genetic correlations among traits, can be used to supply a more detailed picture of multitrait divergence. We apply the method to naturally occurring genetic variation for a suite of sexually selected display traits in Drosophila serrata. The analyses suggest the operation of divergent multivariate selection that has influenced multiple independent axes of genetic variance in a sex-specific manner. Finally, we show how a comparison of the components of F(STq), the average within and among population genetic variance-covariance matrices, G(W) and G(B), can be used as an additional test of the null expectation of neutral divergence, and allows for an investigation of whether natural populations have diverged along major or minor axes of genetic variance.
Bottazzi, Maria Elena; Zhu, Xiaoyun; Böhmer, Ralph M.; Assoian, Richard K.
1999-01-01
We have examined the regulation of p21cip1 by soluble mitogens and cell anchorage as well as the relationship between the expression of p21cip1 and activation of the ERK subfamily of MAP kinases. We find that p21cip1 expression in G1 phase can be divided into two discrete phases: an initial induction that requires growth factors and the activation of ERK, and then a subsequent decline that is enhanced by cell anchorage in an ERK-independent manner. In contrast to the induction of cyclin D1, the induction of p21cip1 is mediated by transient ERK activity. Comparative studies with wild-type and p21cip1-null fibroblasts indicate that adhesion-dependent regulation of p21cip1 is important for proper control of cyclin E–cdk2 activity. These data lead to a model in which mitogens and anchorage act in a parallel fashion to regulate G1 phase expression of p21cip1. They also show that (a) growth factors and growth factor/extracellular matrix cooperation can have different roles in regulating G1 phase ERK activity and (b) both transient and sustained ERK signals have functionally significant roles in controlling cell cycle progression through G1 phase. PMID:10491389
Doğan, Gülnihal Emrem; Demir, Turgut; Aksoy, Hülya; Sağlam, Ebru; Laloğlu, Esra; Yildirim, Abdulkadir
2016-10-01
Matrix-Gla Protein (MGP) is one of the major Gla-containing protein associated with calcification process. It also has a high affinity for Ca(2+) and hydroxyapatite. In this study we aimed to evaluate the MGP rs4236 [A/G] gene polymorphism in association with subgingival dental calculus. Also a possible relationship between MGP gene polymorphism and serum and GCF levels of MGP were examined. MGP rs4236 [A/G] gene polymorphism was investigated in 110 patients with or without subgingival dental calculus, using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) techniques. Additionally, serum and GCF levels of MGP of the patients were compared according to subgingival dental calculus. Comparison of patients with and without subgingival dental calculus showed no statistically significant difference in MGP rs4236 [A/G] gene polymorphism (p=0.368). MGP concentrations in GCF of patients with subgingival dental calculus were statistically higher than those without subgingival dental calculus (p=0.032). However, a significant association was not observed between the genotypes of AA, AG and GG of the MGP rs4236 gene and the serum and GCF concentrations of MGP in subjects. In this study, it was found that MGP rs4236 [A/G] gene polymorphism was not to be associated with subgingival dental calculus. Also, that GCF MGP levels were detected higher in patients with subgingival dental calculus than those without subgingival dental calculus independently of polymorphism, may be the effect of adaptive mechanism to inhibit calculus formation. Copyright © 2016 Elsevier Ltd. All rights reserved.
Horwacik, Irena; Rokita, Hanna
2017-05-01
Children diagnosed with high risk neuroblastoma have poor prognosis which stimulates efforts to broaden therapies of the neoplasm. GD2-ganglioside (GD2) marks neuroblastoma cells and is a target for monoclonal antibodies. We have recently shown that some neuroblastoma cell lines are sensitive to direct cytotoxicity of the anti-GD2 mouse monoclonal antibody 14G2a (mAb). For IMR-32 and LA-N-1 cell lines, treatment with the 14G2a mAb induced evident changes in appearance such as cell rounding, aggregation, loose contact with culture plastic, or detachment. Such findings prompted us to investigate whether modulation of attachment of neuroblastoma cells to extracellular matrix (ECM) proteins can affect their sensitivity to the 14G2a mAb treatment. First, using ultra-low attachment plates, we show that survival of the IMR-32, LA-N-1, LA-N-5, CHP-134 and Kelly cells depends on attachment. Next, we compared cellular ATP levels of the cell lines treated with the 14G2a mAb using uncoated, fibronectin-, collagen IV-coated surfaces to show that the ECM proteins slightly modulate sensitivity of the cell lines to the mAb. Then, we characterized presence of selected integrin subunits or their complexes on the cell surface. Finally, we applied small molecule inhibitors of selected integrin complexes: obtustatin (inhibiting α1β1 heterodimer), BIO 1211 (inhibiting active α4β1 heterodimer), cilengitide and SB273005 (inhibitors of αVβ3, αVβ5 heterodimers) to verify their effects on attachment of cell lines, cellular ATP levels, and in some experiments activities of apoptosis-executing caspase-3 and -7, for the compounds used alone or in combination with the 14G2a mAb. We characterized levels of total FAK (focal adhesion kinase), p-FAK (Tyr397) in IMR-32 cells treated with BIO 1211, and in LA-N-5, Kelly and SK-N-SH cells treated with SB273005. Our results extend knowledge on factors influencing cytotoxicity of 14G2a.
NASA Astrophysics Data System (ADS)
Grein, Friedrich
2005-03-01
For Nen-AlO (n=2, 4, 6, 8, 10) and Arn-AlO clusters (n=2, 4, 6, 8), the perpendicular (relative to AlO) component of the g tensor was calculated by second-order perturbation theory, using multireference configuration-interaction wave functions. The rare-gas (Rg) atoms were placed axially and/or off axially (one or two rings of four Rg atoms each), and the distance of the Rg atoms from the Al and O atoms, or from the AlO axis, was varied from 4 to 12 bohrs. Rg atoms placed axially mostly increase g⊥, whereas off-axially placed ones lower it below the gas-phase value of AlO. The largest deviations from g⊥ of isolated AlO occur at Ne-Al,O distances of 5-6 bohrs, and Ar-Al,O distances of 6-9 bohrs, with maximal lowerings of about 1600 ppm for Ne and about 2200 ppm (estimated) for Ar in the case of two axial and eight off-axial Rg atoms. Electron spin resonance studies by Knight and Weltner found large matrix effects for AlO, with downshifts of g⊥ observed to be about 450 and 1150 ppm in Ne and Ar matrices, respectively.
NASA Astrophysics Data System (ADS)
Rashdan, M.
2015-05-01
Sub-barrier fusion cross sections for reactions involving stable and very neutron-rich nuclei, which may be important in determining the composition and heating of the crust of accreting neutron stars, are calculated using internuclear potentials derived from the microscopic Brueckner G -matrix and Skyrme SKM* and SLy4 energy density functionals. Microscopic Skyrme-Hartree-Fock proton and neutron density distributions are used. No parameters have been fit to fusion data. Calculations are performed for the isotopic reactions 16O+16O,16O+24O,16O+28O,24O+24O,12C+16O,12C+24O , and 12C+12C , which are of great astrophysical importance for the understanding of the time scale and the nucleosynthesis during late stellar evolution. The coupling to the low lying excited states is considered through the ccfull code. I compare my results with the time-dependent-Hartree-Fock calculations and with the São Paulo model as well as the experimental data. I found a remarkable agreement with the fusion cross sections for stable nuclei.
Saito, Tomoaki; Kasamatsu, Atsushi; Ogawara, Katsunori; Miyamoto, Isao; Saito, Kengo; Iyoda, Manabu; Suzuki, Takane; Endo-Sakamoto, Yosuke; Shiiba, Masashi; Tanzawa, Hideki; Uzawa, Katsuhiro
2015-01-01
Background Semaphorins (SEMAs) consist of a large family of secreted and membrane-anchored proteins that are important in neuronal pathfinding and axon guidance in selected areas of the developing nervous system. Of them, SEMA7A has been reported to have a chemotactic activity in neurogenesis and to be an immunomodulator; however, little is known about the relevance of SEMA7A in the behaviors of oral squamous cell carcinoma (OSCC). Methods We evaluated SEMA7A expression in OSCC-derived cell lines and primary OSCC samples using quantitative reverse transcriptase-polymerase chain reaction, immunoblotting, and semiquantitative immunohistochemistry (sq-IHC). In addition, SEMA7A knockdown cells (shSEMA7A cells) were used for functional experiments, including cellular proliferation, invasiveness, and migration assays. We also analyzed the clinical correlation between SEMA7A status and clinical behaviors in patients with OSCC. Results SEMA7A mRNA and protein were up-regulated significantly (P<0.05) in OSCC-derived cell lines compared with human normal oral keratinocytes. The shSEMA7A cells showed decreased cellular growth by cell-cycle arrest at the G1 phase, resulting from up-regulation of cyclin-dependent kinase inhibitors (p21Cip1 and p27Kip1) and down-regulation of cyclins (cyclin D1, cyclin E) and cyclin-dependent kinases (CDK2, CDK4, and CDK6); and decreased invasiveness and migration activities by reduced secretion of matrix metalloproteases (MMPs) (MMP-2, proMMP-2, pro-MMP-9), and expression of membrane type 1- MMP (MT1-MMP). We also found inactivation of the extracellular regulated kinase 1/2 and AKT pathways, an upstream molecule of cell-cycle arrest at the G1 phase, and reduced secretion of MMPs in shSEMA7A cells. sq-IHC showed that SEMA7A expression in the primary OSCCs was significantly (P = 0.001) greater than that in normal counterparts and was correlated with primary tumoral size (P = 0.0254) and regional lymph node metastasis (P = 0.0002). Conclusion Our
NASA Astrophysics Data System (ADS)
Chillier, Xavier D. F.; Stone, Bradley M.; Joblin, Christine; Salama, Farid; Allamandola, Louis J.
2002-04-01
Fluorescence spectra of the perylene cation, isolated in an argon matrix and pumped by direct laser excitation via the D2(2B3g)←D0(2Au) and D5(2B3g)←D0(2Au) transitions, are presented. Direct excitation into the D5 or D2 states is followed by rapid nonradiative relaxation to D1 that, in turn, relaxes radiatively. Excitation spectroscopy across the D2(2B3g)←D0(2Au) transition near 731 nm shows that site splitting plays little or no role in determining the spectral substructure in the ion spectra. Tentative assignments for ground state vibrational frequencies are made by a comparison of spectral intervals with calculated normal mode frequencies, with the strongest IR bands leading to the most intense vibronic bands.
Shapes of the 16N and 15C beta spectra and extraction of matrix elements for 15C(β-)15N(g.s.)
NASA Astrophysics Data System (ADS)
Warburton, E. K.; Alburger, D. E.; Millener, D. J.
1984-06-01
The 16N and 15C spectra measured by Alburger, Gallmann, and Wilkinson were reanalyzed to obtain more accurate branching ratios as well as a shape factor for the first-forbidden, nonunique 15C(12+)-->15N(12-) decay. 16N β- branches were derived to the levels at 0 and 6.13 MeV of 27.9(5)% and 66.3(6)%, respectively; 15C β- branches were found to 15N levels at 0 and 5.30 MeV of 36.8(8)% and 63.2(8)%, respectively. The 15C shape factor was found to deviate significantly from the allowed shape. Analysis of the shape factor results in the determination of the rank zero component of the transition and determination of the two independent matrix elements which contribute to the rank one component. The possible role of muon capture in determining the rank zero matrix elements is considered. Comparisons, for both the 15C(12+)-->15N(12-) and 16N(0-)-->16O(0+) transitions, are made to shell-model calculations with particular emphasis on the sensitivity of the nuclear matrix elements to the choice of the single particle wave function. It is found that rank zero rates calculated with Woods-Saxon wave functions are much smaller than those calculated with harmonic oscillator wave functions. Possible meson-exchange contributions to the rank zero rates are discussed in light of this finding.
Kawaguchi-Sakita, Nobuko; Kaneshiro-Nakagawa, Kaoru; Kawashima, Masahiro; Sugimoto, Masahiro; Tokiwa, Mariko; Suzuki, Eiji; Kajihara, Shigeki; Fujita, Yuichiro; Iwamoto, Shinichi; Tanaka, Koichi; Toi, Masakazu
2016-01-22
Herein, we report that breast cancer (BC) patients can be distinguished from cancer-free (NC) controls by serum immunoglobulin G (IgG) crystallizable fragment (Fc) region N-glycosylation profiling using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). Recently, there has been much progress in the field of tumor immunology. However, to date, the role and biomarker potential of IgG Fc region N-glycosylation, which affects the function of antibodies, have not been examined in BC. In the present study, we profiled serum IgG Fc region N-glycans in BC patients (N = 90) and NC controls (N = 54) using MALDI-MS. An IgG Fc region N-glycan-based multiple logistic regression model was produced which could distinguish BC patients from NC controls (area under the receiver operative characteristic curve = 0.874). Furthermore, stage 0 patients could also be distinguished using this model. These results suggest that an unknown humoral factor or soluble mediator affects IgGs from the earliest stage of breast cancer, and also suggests that IgG Fc region N-glycosylation may play a role in tumor biology. Although further investigation is required, our findings are the evidence that IgG N-glycan profiling has the potential to be used as a breast cancer biomarker and may provide the insights into tumor immunology. Copyright © 2015 Elsevier Inc. All rights reserved.
Moon, H-G; Qin, Z; Quan, T; Xie, L; Dela Cruz, C S; Jin, Y
2015-03-01
To defend against pulmonary infections, lung epithelial cells are equipped with complex innate immunity closely linked to inflammation. Dysregulated innate immunity/inflammation leads to self-perpetuating lung injury. The CpG motif in bacterial DNA is one of the factors involved in bacterial infection-associated inflammation. Bacterial DNA and synthetic CpG oligonucleotide (ODN) induced CCN1 secretion from lung epithelial cells, functioning as a potential "braking" signal to prevent uncontrolled inflammatory responses. CpG ODN-induced endoplasmic reticulum (ER) stress resulted in Src-Y527 phosphorylation (pY527) and Src/CCN1 vWF domain dissociation. Src-Y527 activated caveolin-1 (cav-1) phosphorylation at Y14 and then modulated CCN1 secretion via pCav-1 interaction with the CCN1 IGFbp domain. Functionally, secreted CCN1 promoted anti-inflammatory cytokine interleukin (IL)-10 release from epithelial cells via integrin αVβ6-PKC, and this subsequently suppressed tumor necrosis factor (TNF)-α, macrophage inflammatory protein 2 (MIP-2)-2 secretion and neutrophil infiltration in the lungs. Collectively, bacterial DNA/CpG ODN-stimulated CCN1 secretion via the BiP/GRP78-Src(Y527)-JNK-Cav-1(Y14) pathway and CpG-induced CCN1 conferred anti-inflammatory roles. Our studies suggested a novel paradigm by which the lung epithelium maintains innate immune homeostasis after bacterial infection.
ERIC Educational Resources Information Center
Rushton, J. Philippe
2004-01-01
First, I describe why intelligence (Spearman's "g") can only be fully understood through "r-K" theory, which places it into an evolutionary framework along with brain size, longevity, maturation speed, and several other life-history traits. The "r-K" formulation explains why IQ predicts longevity and also why the gap in mortality rates between…
ERIC Educational Resources Information Center
Rushton, J. Philippe
2004-01-01
First, I describe why intelligence (Spearman's "g") can only be fully understood through "r-K" theory, which places it into an evolutionary framework along with brain size, longevity, maturation speed, and several other life-history traits. The "r-K" formulation explains why IQ predicts longevity and also why the gap in mortality rates between…
Markowski, Adam S; Mannan, M Sam
2008-11-15
A risk matrix is a mechanism to characterize and rank process risks that are typically identified through one or more multifunctional reviews (e.g., process hazard analysis, audits, or incident investigation). This paper describes a procedure for developing a fuzzy risk matrix that may be used for emerging fuzzy logic applications in different safety analyses (e.g., LOPA). The fuzzification of frequency and severity of the consequences of the incident scenario are described which are basic inputs for fuzzy risk matrix. Subsequently using different design of risk matrix, fuzzy rules are established enabling the development of fuzzy risk matrices. Three types of fuzzy risk matrix have been developed (low-cost, standard, and high-cost), and using a distillation column case study, the effect of the design on final defuzzified risk index is demonstrated.
NASA Astrophysics Data System (ADS)
Horáček, J.; Mach, P.; Urban, J.
2010-09-01
The method of analytic continuation in the coupling constant in combination with use of the statistical Padé approximation is applied to the determination of resonance energy and width of the 2Πg state of N2-. It is shown that standard quantum chemistry codes provide accurate data which can be used for analytic continuation in the coupling constant, and the resonance energy and width can be inferred with an accuracy comparable to other more elaborate methods.
L'Empereur, Karen; Stadalius, Marilyn; Zhu, Yongdong; Mansoori, Bashir A; Isemura, Tsuguhide; Kaiser, Mary A; Knaup, Wolfgang; Noguchi, Masahiro
2008-08-01
Fluorotelomer-based acrylic polymers are applied to the surface of carpet to impart oil, stain, and water repellence properties. Concerns that fluorotelomer-based polymers are a possible source of "low level" exposure to humans, coupled with their widespread use have prompted the need to develop a method to detect and measure perfluorooctanoate (PFO) in carpet. A liquid chromatography tandem mass spectrometry method for the determination of PFO in carpet using a dual labeled 13C-perfluoroctanoic acid (13C-PFOA) internal standard is successfully developed and validated. Levels of PFO are determined using a gradient, reversed-phase high-performance liquid chromatography (HPLC) method with acetic acid acidified water-methanol, separated on a 50 mm Phenomenex Synergi Polar RP column. Ions monitored are 413 (parent) and 369 (daughter) for PFO and 415 (parent) and 370 (daughter) for dual labeled 13C-PFOA internal standard. Accuracy and precision over three days for 5 to 900 ng/g PFO in carpet ranged from 2.4% to 7.6% and 3.7% to 14.1%, respectively. Overall extraction efficiency for samples (n=30) fortified with 13C-PFOA at 20 ng/g and perfluorooctanoic acid (PFOA) at 5, 50, and 500 ng/g is 98.9%+/-8.1%. Specificity of the method was evaluated with two different carpet samples.
Optical coherency matrix tomography
Kagalwala, Kumel H.; Kondakci, H. Esat; Abouraddy, Ayman F.; Saleh, Bahaa E. A.
2015-01-01
The coherence of an optical beam having multiple degrees of freedom (DoFs) is described by a 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 binary DoFs where G is a 4 × 4 matrix. We establish a methodical yet versatile approach—optical coherency matrix tomography—for reconstructing G that exploits the analogy between this problem in classical optics and that of tomographically reconstructing the density matrix associated with multipartite quantum states in quantum information science. Here G is reconstructed from a minimal set of linearly independent measurements, each a cascade of projective measurements for each DoF. We report the first experimental measurements of the 4 × 4 coherency matrix G associated with an electromagnetic beam in which polarization and a spatial DoF are relevant, ranging from the traditional two-point Young’s double slit to spatial parity and orbital angular momentum modes. PMID:26478452
Kunte, Mugdha; Desai, Krutika
2017-03-30
Spirulina platensis :have been studied for several biological activities. In the current study C-phycocyanin containing protein extract (C-PC extract) of Spirulina platensis have been studied for its effect on human matrix metalloproteinases (MMP-1, MMP-2 and MMP-9) and tissue inhibitors of MMPs (TIMP-1 and TIMP-2). In the present study, breast cancer cell line (MDA-MB 231) and hepatocellular cancer cell line (HepG2) were examined for inhibition of MMPs at different levels of expression after C-PC extract treatment. Herein, we have demonstrated that C-PC extract significantly reduced activity of MMP-2 by 55.13% and MMP-9 by 57.9% in HepG2 cells at 15 μg concentration. Additionally, the treatment has reduced mRNA expression of MMP-2 and MMP-9 at 20 μg concentration by 1.65-folds and 1.66-folds respectively. The C-PC extract treatment have also downregulated a mRNA expression of TIMP-2 by 1.12 folds at 20 μg concentration in HepG2 cells. Together, these results indicate that C-PC, extract successfully inhibited MMP-2 and -9 at different levels of expression and TIMP-2 at a mRNA expression level; however, extract did not have any effect on MMP-1 expressed in MDA-MB231 and TIMP-1 expressed in HepG2 cells as well as the exact mechanism of inhibition of MMP-2, MMP-9 and TIMP-2 remained unclear.
Hao, Zhangying; Avci, Utku; Tan, Li; Zhu, Xiang; Glushka, John; Pattathil, Sivakumar; Eberhard, Stefan; Sholes, Tipton; Rothstein, Grace E.; Lukowitz, Wolfgang; Orlando, Ron; Hahn, Michael G.; Mohnen, Debra
2014-01-01
GAlactUronosylTransferase12 (GAUT12)/IRregular Xylem8 (IRX8) is a putative glycosyltransferase involved in Arabidopsis secondary cell wall biosynthesis. Previous work showed that Arabidopsis irregular xylem8 (irx8) mutants have collapsed xylem due to a reduction in xylan and a lesser reduction in a subfraction of homogalacturonan (HG). We now show that male sterility in the irx8 mutant is due to indehiscent anthers caused by reduced deposition of xylan and lignin in the endothecium cell layer. The reduced lignin content was demonstrated by histochemical lignin staining and pyrolysis Molecular Beam Mass Spectrometry (pyMBMS) and is associated with reduced lignin biosynthesis in irx8 stems. Examination of sequential chemical extracts of stem walls using 2D 13C-1H Heteronuclear Single-Quantum Correlation (HSQC) NMR spectroscopy and antibody-based glycome profiling revealed a reduction in G lignin in the 1 M KOH extract and a concomitant loss of xylan, arabinogalactan and pectin epitopes in the ammonium oxalate, sodium carbonate, and 1 M KOH extracts from the irx8 walls compared with wild-type walls. Immunolabeling of stem sections using the monoclonal antibody CCRC-M138 reactive against an unsubstituted xylopentaose epitope revealed a bi-lamellate pattern in wild-type fiber cells and a collapsed bi-layer in irx8 cells, suggesting that at least in fiber cells, GAUT12 participates in the synthesis of a specific layer or type of xylan or helps to provide an architecture framework required for the native xylan deposition pattern. The results support the hypothesis that GAUT12 functions in the synthesis of a structure required for xylan and lignin deposition during secondary cell wall formation. PMID:25120548
NASA Astrophysics Data System (ADS)
Nikitin, Anatoly G.; Karadzhov, Yuri
2011-07-01
We present a collection of matrix-valued shape invariant potentials which give rise to new exactly solvable problems of SUSY quantum mechanics. It includes all irreducible matrix superpotentials of the generic form W=kQ+\\frac{1}{k} R+P, where k is a variable parameter, Q is the unit matrix multiplied by a real-valued function of independent variable x, and P and R are the Hermitian matrices depending on x. In particular, we recover the Pron'ko-Stroganov 'matrix Coulomb potential' and all known scalar shape invariant potentials of SUSY quantum mechanics. In addition, five new shape invariant potentials are presented. Three of them admit a dual shape invariance, i.e. the related Hamiltonians can be factorized using two non-equivalent superpotentials. We find discrete spectrum and eigenvectors for the corresponding Schrödinger equations and prove that these eigenvectors are normalizable.
NASA Astrophysics Data System (ADS)
Craps, Ben; Evnin, Oleg; Nguyen, Kévin
2017-02-01
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.
John, Harald; Breyer, Felicitas; Thumfart, Jörg Oliver; Höchstetter, Hans; Thiermann, Horst
2010-11-01
Toxic organophosphorus compounds (OPC), e.g., pesticides and nerve agents (NA), are known to phosphylate distinct endogenous proteins in vivo and in vitro. OPC adducts of butyrylcholinesterase and albumin are considered to be valuable biomarkers for retrospective verification of OPC exposure. Therefore, we have detected and identified novel adducts of human serum albumin (HSA) by means of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Pure albumin and plasma were incubated with numerous pesticides and NA of the V- and G-type in different molar ratios. Samples were prepared either by sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by in-gel enzymatic cleavage using endoproteinase Glu-C (Glu-C) or by combining highly albumin-selective affinity extraction with ultrafiltration followed by reduction, carbamidomethylation, and enzymatic cleavage (Glu-C) prior to MALDI-TOF MS analysis. Characteristic mass shifts for phosphylation revealed tyrosine adducts at Y(411) (Y(401)KFQNALLVRY(411)TKKVPQVSTPTLVE(425)), Y(148) and Y(150) (I(142)ARRHPY(148)FY(150)APE(153), single and double labeled), and Y(161) (L(154)LFFAKRY(161)KAAFTE(167)) produced by original NA (tabun, sarin, soman, cyclosarin, VX, Chinese VX, and Russian VX) as well as by chlorpyrifos-oxon, diisopropyl fluorophosphate (DFP), paraoxon-ethyl (POE), and profenofos. MALDI-MS/MS of the single-labeled I(142)-E(153) peptide demonstrated that Y(150) was phosphylated with preference to Y(148). Aged albumin adducts were not detected. The procedure described was reproducible and feasible for detection of adducts at the most reactive Y(411)-residue (S/N ≥ 3) when at least 1% of total albumin was labeled. This was achieved by incubating plasma with molar HSA/OPC ratios ranging from approximately 1:0.03 (all G-type NA, DFP, and POE) to 1:3 (V-type NA, profenofos). Relative signal intensity of the Y(411) adduct correlated well with the spotted relative
Metz, William C.; Metz, W. Chris; Mitrani, Jacques E.; Hewett, Jr., Paul L.; Jones, Christopher A.
2004-12-31
Sync Matrix provides a graphic display of the relationships among all of the response activities of each jurisdiction. This is accomplished through software that organizes and displays the activities by jurisdiction, function, and time for easy review and analysis. The software can also integrate the displays of multiple jurisdictions to allow examination of the total response.
1998-06-01
on courses being taught at NPS. LIST OF REFERENCES [1] Anton , Howard , Elementary Linear Algebra , John Wiley and Sons, New York, New York, 1994...and computational techniques for solving systems of linear equations. The goal is to enhance current matrix algebra textbooks and help the beginning... algebra is the study of algebraic operations on matrices and of their applications, primarily for solving systems of linear equations. Systems of
NASA Technical Reports Server (NTRS)
Chillier, Xavier D. F.; Stone, Bradley M.; Joblin, Christine; Salama, Farid; Allamandola, Louis J.; DeVincenzi, Donald L. (Technical Monitor)
2001-01-01
Fluorescence spectra of the perylene cation, pumped by direct laser excitation via the D(sub 2)((2)B(sub 3g)) (left arrow) D(sub 0)((2)A(sub u)) and D(sub 5)(2)B(sub 3g)) (left arrow) D(sub 0)((2)A(sub u)) transitions, are presented. Direct excitation into the D5 or D2 states is followed by rapid non-radiative relaxation to D1 that, in turn,relaxes radiatively. Excitation spectroscopy across the D(sub 2)((2)B(sub 3g)) (left arrow) D(sub 0)((2)A(sub u)) transition near 730 nm shows that site splitting plays little or no role in determining the spectral substructure in the ion spectra. Tentative assignments for ground state vibrational frequencies are made by comparison of spectral intervals with calculated normal mode frequencies.
Silva, John-Paul; Vetterlein, Olivia; Jose, Joby; Peters, Shirley; Kirby, Hishani
2015-02-27
Human immunoglobulin G isotype 4 (IgG4) antibodies (Abs) are potential candidates for immunotherapy when reduced effector functions are desirable. IgG4 Abs are dynamic molecules able to undergo a process known as Fab arm exchange (FAE). This results in functionally monovalent, bispecific antibodies (bsAbs) with unknown specificity and hence, potentially, reduced therapeutic efficacy. IgG4 FAE is suggested to be an important biological mechanism that provides the basis for the anti-inflammatory activity attributed to IgG4 Abs. To date, the mechanism of FAE is not entirely understood and studies measuring FAE in ex vivo matrices have been hampered by the presence and abundance of endogenous IgG4 wild-type (WT) Abs. Using representative humanized WT IgG4 monoclonal Abs, namely, anti-IL-6 and anti-TNF, and a core-hinge stabilized serine 228 to proline (S228P) anti-IL-6 IgG4 mutant, it is demonstrated for the first time how anti-IgG4 affinity chromatography can be used to prepare physiologically relevant matrices for assessing and quantifying FAE. A novel method for quantifying FAE using a single MSD immunoassay is also reported and confirms previous findings that, dependent on the redox conditions, the S228P mutation can prevent IgG4 FAE to undetectable levels both in vitro and in vivo. Together, the findings and novel methodologies will allow researchers to monitor and quantify FAE of their own IgG4 molecules in physiologically relevant matrices.
Silva, John-Paul; Vetterlein, Olivia; Jose, Joby; Peters, Shirley; Kirby, Hishani
2015-01-01
Human immunoglobulin G isotype 4 (IgG4) antibodies (Abs) are potential candidates for immunotherapy when reduced effector functions are desirable. IgG4 Abs are dynamic molecules able to undergo a process known as Fab arm exchange (FAE). This results in functionally monovalent, bispecific antibodies (bsAbs) with unknown specificity and hence, potentially, reduced therapeutic efficacy. IgG4 FAE is suggested to be an important biological mechanism that provides the basis for the anti-inflammatory activity attributed to IgG4 Abs. To date, the mechanism of FAE is not entirely understood and studies measuring FAE in ex vivo matrices have been hampered by the presence and abundance of endogenous IgG4 wild-type (WT) Abs. Using representative humanized WT IgG4 monoclonal Abs, namely, anti-IL-6 and anti-TNF, and a core-hinge stabilized serine 228 to proline (S228P) anti-IL-6 IgG4 mutant, it is demonstrated for the first time how anti-IgG4 affinity chromatography can be used to prepare physiologically relevant matrices for assessing and quantifying FAE. A novel method for quantifying FAE using a single MSD immunoassay is also reported and confirms previous findings that, dependent on the redox conditions, the S228P mutation can prevent IgG4 FAE to undetectable levels both in vitro and in vivo. Together, the findings and novel methodologies will allow researchers to monitor and quantify FAE of their own IgG4 molecules in physiologically relevant matrices. PMID:25568323
Hybrid matrix fiber composites
Deteresa, Steven J.; Lyon, Richard E.; Groves, Scott E.
2003-07-15
Hybrid matrix fiber composites having enhanced compressive performance as well as enhanced stiffness, toughness and durability suitable for compression-critical applications. The methods for producing the fiber composites using matrix hybridization. The hybrid matrix fiber composites include two chemically or physically bonded matrix materials, whereas the first matrix materials are used to impregnate multi-filament fibers formed into ribbons and the second matrix material is placed around and between the fiber ribbons that are impregnated with the first matrix material and both matrix materials are cured and solidified.
Hashimoto, Ko; Otero, Miguel; Imagawa, Kei; de Andrés, María C; Coico, Jonathan M; Roach, Helmtrud I; Oreffo, Richard O C; Marcu, Kenneth B; Goldring, Mary B
2013-04-05
The role of DNA methylation in the regulation of catabolic genes such as MMP13 and IL1B, which have sparse CpG islands, is poorly understood in the context of musculoskeletal diseases. We report that demethylation of specific CpG sites at -110 bp and -299 bp of the proximal MMP13 and IL1B promoters, respectively, detected by in situ methylation analysis of chondrocytes obtained directly from human cartilage, strongly correlated with higher levels of gene expression. The methylation status of these sites had a significant impact on promoter activities in chondrocytes, as revealed in transfection experiments with site-directed CpG mutants in a CpG-free luciferase reporter. Methylation of the -110 and -299 CpG sites, which reside within a hypoxia-inducible factor (HIF) consensus motif in the respective MMP13 and IL1B promoters, produced the most marked suppression of their transcriptional activities. Methylation of the -110 bp CpG site in the MMP13 promoter inhibited its HIF-2α-driven transactivation and decreased HIF-2α binding to the MMP13 proximal promoter in chromatin immunoprecipitation assays. In contrast to HIF-2α, MMP13 transcriptional regulation by other positive (RUNX2, AP-1, ELF3) and negative (Sp1, GATA1, and USF1) factors was not affected by methylation status. However, unlike the MMP13 promoter, IL1B was not susceptible to HIF-2α transactivation, indicating that the -299 CpG site in the IL1B promoter must interact with other transcription factors to modulate IL1B transcriptional activity. Taken together, our data reveal that the methylation of different CpG sites in the proximal promoters of the human MMP13 and IL1B genes modulates their transcription by distinct mechanisms.
NASA Astrophysics Data System (ADS)
He, Yang-Hui
2003-02-01
We present, in explicit matrix representation and a modernity befitting the community, the classification of the finite discrete subgroups of G2 and compute the McKay quivers arising therefrom. Of physical interest are the classes of N = 1 gauge theories descending from M-theory and of mathematical interest are possible steps toward a systematic study of crepant resolutions to smooth G2 manifolds as well as generalised McKay Correspondences. This writing is a companion monograph to hep-th/9811183 and hep-th/9905212, wherein the analogues for Calabi-Yau three- and four-folds were considered.
The role of g9/2 intruder state in the nuclear matrix elements of 76Ge → 76Se 2νββ(0+ → 0+) decay
NASA Astrophysics Data System (ADS)
Valencia, J. P.
2016-07-01
I propose a model for the upper-part of pf-shell, which consists of p1/2, p3/2, f5/2 and g9/2 single-particle orbits. While the pf-subshell (or d ˜s -subshell, i.e. η ˜=2 ,s˜1 /2,d˜3 /2,d˜5 /2) is governed by the SU˜S ˜T(4 )⊗U˜L ˜(6 ) symmetry, the g9/2 intruder state is governed by the seniority model. The nuclear states of 76Ge and 76Se are expressed as direct products of the d ˜s subshell component and the g-subshell one. The five-dimensional quasispin formalism with seniority zero restriction is used for a classification in the g-subshell. In the d ˜s -subshell, for each configuration [Mπ,Mν]d ˜s I choose only the most symmetric U˜L ˜(6 ) representations with total pseudo-spin S ˜=0 . Therefore, all the configurations are given by (0 Y 0 ˜) {4P2Y ˜} and (0 Y 0 -20 ˜) {4P +12Y -2 ˜} for 76Ge and 76Se, respectively with Y = 6-(nν - nπ)/2 and P = (4 - nπ)/2. I derive an explicit expression for the NME of the 2νββ(0+ → 0+) in the closure approximation.
A matrix analysis of conjugate gradient algorithms
Ashby, S.F.; Gutknecht, M.H.
1993-04-01
This paper explores the relationships between the conjugate gradient algorithms Orthodir, Orthomin, and Orthores. To facilitate this exploration, a matrix formulation for each algorithm is given. It is shown that Orthodir directly computes a Hessenberg matrix H{sub k} at step k. Orthores also computes a Hessenberg matrix, G{sub k}, which is similar to a Hessenberg matrix obtained from H{sub k} by perturbing its last column. (This perturbation vanishes at convergence.) Orthomin, on the other hand, computes a UL and LU factorization of the perturbed H{sub k} and G{sub k}, respectively. The breakdown of Orthomin and Orthores are interpreted in terms of these underlying matrix factorizations. A connection with Lanczos algorithms is also examined, as is the special case of B-normal(1) matrices (for which efficient three-term CG algorithms exist).
Farooque, Mohammad; Yuh, Chao-Yi
1996-01-01
A carbonate fuel cell matrix comprising support particles and crack attenuator particles which are made platelet in shape to increase the resistance of the matrix to through cracking. Also disclosed is a matrix having porous crack attenuator particles and a matrix whose crack attenuator particles have a thermal coefficient of expansion which is significantly different from that of the support particles, and a method of making platelet-shaped crack attenuator particles.
Farooque, M.; Yuh, C.Y.
1996-12-03
A carbonate fuel cell matrix is described comprising support particles and crack attenuator particles which are made platelet in shape to increase the resistance of the matrix to through cracking. Also disclosed is a matrix having porous crack attenuator particles and a matrix whose crack attenuator particles have a thermal coefficient of expansion which is significantly different from that of the support particles, and a method of making platelet-shaped crack attenuator particles. 8 figs.
Matrix with Prescribed Eigenvectors
ERIC Educational Resources Information Center
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…
Matrix with Prescribed Eigenvectors
ERIC Educational Resources Information Center
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…
Matrix Training of Preliteracy Skills with Preschoolers with Autism
ERIC Educational Resources Information Center
Axe, Judah B.; Sainato, Diane M.
2010-01-01
Matrix training is a generative approach to instruction in which words are arranged in a matrix so that some multiword phrases are taught and others emerge without direct teaching. We taught 4 preschoolers with autism to follow instructions to perform action-picture combinations (e.g., circle the pepper, underline the deer). Each matrix contained…
Parce, J. Wallace; Bernatis, Paul; Dubrow, Robert; Freeman, William P.; Gamoras, Joel; Kan, Shihai; Meisel, Andreas; Qian, Baixin; Whiteford, Jeffery A.; Ziebarth, Jonathan
2010-01-12
Matrixes doped with semiconductor nanocrystals are provided. In certain embodiments, the semiconductor nanocrystals have a size and composition such that they absorb or emit light at particular wavelengths. The nanocrystals can comprise ligands that allow for mixing with various matrix materials, including polymers, such that a minimal portion of light is scattered by the matrixes. The matrixes of the present invention can also be utilized in refractive index matching applications. In other embodiments, semiconductor nanocrystals are embedded within matrixes to form a nanocrystal density gradient, thereby creating an effective refractive index gradient. The matrixes of the present invention can also be used as filters and antireflective coatings on optical devices and as down-converting layers. Processes for producing matrixes comprising semiconductor nanocrystals are also provided. Nanostructures having high quantum efficiency, small size, and/or a narrow size distribution are also described, as are methods of producing indium phosphide nanostructures and core-shell nanostructures with Group II-VI shells.
String coupling and interactions in type IIB matrix model
Kitazawa, Yoshihisa; Nagaoka, Satoshi
2009-05-15
We investigate the interactions of closed strings in a IIB matrix model. The basic interaction of the closed superstring is realized by the recombination of two intersecting strings. Such interaction is investigated in a IIB matrix model via two-dimensional noncommutative gauge theory in the IR limit. By estimating the probability of the recombination, we identify the string coupling g{sub s} in the IIB matrix model. We confirm that our identification is consistent with matrix string theory.
ERIC Educational Resources Information Center
Miller, Phyllis, Ed.
1999-01-01
This issue of a research journal on gifted education explores the concept of intelligence and giftedness, talent development, gifted education, and educational research. Specific articles include: (1) "Spearman Revisited: Contemporary Views of g" (Milton Dehn); (2) "Exceptionally High Intelligence and Schooling" (Ellen Winner), which argues for…
An ESS maximum principle for matrix games.
Vincent, T L; Cressman, R
2000-11-01
Previous work has demonstrated that for games defined by differential or difference equations with a continuum of strategies, there exists a G-function, related to individual fitness, that must take on a maximum with respect to a virtual variable v whenever v is one of the vectors in the coalition of vectors which make up the evolutionarily stable strategy (ESS). This result, called the ESS maximum principle, is quite useful in determining candidates for an ESS. This principle is reformulated here, so that it may be conveniently applied to matrix games. In particular, we define a matrix game to be one in which fitness is expressed in terms of strategy frequencies and a matrix of expected payoffs. It is shown that the G-function in the matrix game setting must again take on a maximum value at all the strategies which make up the ESS coalition vector. The reformulated maximum principle is applicable to both bilinear and nonlinear matrix games. One advantage in employing this principle to solve the traditional bilinear matrix game is that the same G-function is used to find both pure and mixed strategy solutions by simply specifying an appropriate strategy space. Furthermore we show how the theory may be used to solve matrix games which are not in the usual bilinear form. We examine in detail two nonlinear matrix games: the game between relatives and the sex ratio game. In both of these games an ESS solution is determined. These examples not only illustrate the usefulness of this approach to finding solutions to an expanded class of matrix games, but aids in understanding the nature of the ESS as well.
Schlecht, Martin F.; Kassakian, John G.; Caloggero, Anthony J.; Rhodes, Bruce; Otten, David; Rasmussen, Neil
1982-01-01
An automatic switching matrix that includes an apertured matrix board containing a matrix of wires that can be interconnected at each aperture. Each aperture has associated therewith a conductive pin which, when fully inserted into the associated aperture, effects electrical connection between the wires within that particular aperture. Means is provided for automatically inserting the pins in a determined pattern and for removing all the pins to permit other interconnecting patterns.
Reducibility of Matrix Equations Containing Several Parameters.
1981-12-01
AD-AI15 568 AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOO;-ETC EF G 12 1ADA1551 REDUCIBILITY OF MATRIX EQUATIONS CONTAINING SEVERAL...PARAMETERS.E U)CA E UNCLASSIFIED AFIT/GE/RA/81D-1 N P11111111II soonhh Eu;o I. ’Trm * a, ~t- NMI 4 i’- 00Nt. met r~ REDUCIBILITY OF MATRIX EQUATIONS CONTAINING...1 REDUCIBILITY OF MATRIX EQUATIONS CONTAINING SEVERAL PARAMETERS THESIS Presented to the Faculty of the School of Engineering of the Air Force
Metal matrix composite structures
Krivov, G.A.; Beletsky, V.M.; Gribkov, A.N.
1993-12-31
High strength-weight properties, stiffness and fatigue resistance characteristics together with low sensitivity to stress concentration make metal matrix composites (MMC) rather promising for their use in structures. Metal matrix composites consist of a matrix (aluminum, magnesium, titanium and their alloys are the most frequently used) and reinforcers (carbon and boron fibers, high-strength steel wire, silicon carbide whiskers, etc.). This work considers various types of MMC and their applications in structures. The methods of structure production from metal matrix CM of aluminum-boron system with the help of machining, deformation, part joining by welding and riveting are given.
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.
NASA Technical Reports Server (NTRS)
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.
Grassmann matrix quantum mechanics
Anninos, Dionysios; Denef, Frederik; Monten, Ruben
2016-04-21
We explore quantum mechanical theories whose fundamental degrees of freedom are rectangular matrices with Grassmann valued matrix elements. We study particular models where the low energy sector can be described in terms of a bosonic Hermitian matrix quantum mechanics. We describe the classical curved phase space that emerges in the low energy sector. The phase space lives on a compact Kähler manifold parameterized by a complex matrix, of the type discovered some time ago by Berezin. The emergence of a semiclassical bosonic matrix quantum mechanics at low energies requires that the original Grassmann matrices be in the long rectangular limit.more » In conclusion, we discuss possible holographic interpretations of such matrix models which, by construction, are endowed with a finite dimensional Hilbert space.« less
Grassmann matrix quantum mechanics
Anninos, Dionysios; Denef, Frederik; Monten, Ruben
2016-04-21
We explore quantum mechanical theories whose fundamental degrees of freedom are rectangular matrices with Grassmann valued matrix elements. We study particular models where the low energy sector can be described in terms of a bosonic Hermitian matrix quantum mechanics. We describe the classical curved phase space that emerges in the low energy sector. The phase space lives on a compact Kähler manifold parameterized by a complex matrix, of the type discovered some time ago by Berezin. The emergence of a semiclassical bosonic matrix quantum mechanics at low energies requires that the original Grassmann matrices be in the long rectangular limit. In conclusion, we discuss possible holographic interpretations of such matrix models which, by construction, are endowed with a finite dimensional Hilbert space.
MALDI Matrix Research for Biopolymers
Fukuyama, Yuko
2015-01-01
Matrices are necessary materials for ionizing analytes in matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS). The choice of a matrix appropriate for each analyte controls the analyses. Thus, in some cases, development or improvement of matrices can become a tool for solving problems. This paper reviews MALDI matrix research that the author has conducted in the recent decade. It describes glycopeptide, carbohydrate, or phosphopeptide analyses using 2,5-dihydroxybenzoic acid (2,5-DHB), 1,1,3,3-tetramethylguanidinium (TMG) salts of p-coumaric acid (CA) (G3CA), 3-aminoquinoline (3-AQ)/α-cyano-4-hydroxycinnamic acid (CHCA) (3-AQ/CHCA) or 3-AQ/CA and gengeral peptide, peptide containing disulfide bonds or hydrophobic peptide analyses using butylamine salt of CHCA (CHCAB), 1,5-diaminonaphthalene (1,5-DAN), octyl 2,5-dihydroxybenzoate (alkylated dihydroxybenzoate, ADHB), or 1-(2,4,6-trihydroxyphenyl)octan-1-one (alkylated trihydroxyacetophenone, ATHAP). PMID:26819908
Martens, Jon S.; Hietala, Vincent M.; Plut, Thomas A.
1995-01-01
The present invention comprises a novel matrix amplifier. The matrix amplifier includes an active superconducting power divider (ASPD) having N output ports; N distributed amplifiers each operatively connected to one of the N output ports of the ASPD; and a power combiner having N input ports each operatively connected to one of the N distributed amplifiers. The distributed amplifier can included M stages of amplification by cascading superconducting active devices. The power combiner can include N active elements. The resulting (N.times.M) matrix amplifier can produce signals of high output power, large bandwidth, and low noise.
NASA Astrophysics Data System (ADS)
Morozov, A.
2012-08-01
Partition functions of eigenvalue matrix models possess a number of very different descriptions: as matrix integrals, as solutions to linear and nonlinear equations, as τ-functions of integrable hierarchies and as special-geometry prepotentials, as result of the action of W-operators and of various recursions on elementary input data, as gluing of certain elementary building blocks. All this explains the central role of such matrix models in modern mathematical physics: they provide the basic "special functions" to express the answers and relations between them, and they serve as a dream model of what one should try to achieve in any other field.
Martens, J.S.; Hietala, V.M.; Plut, T.A.
1995-01-03
The present invention comprises a novel matrix amplifier. The matrix amplifier includes an active superconducting power divider (ASPD) having N output ports; N distributed amplifiers each operatively connected to one of the N output ports of the ASPD; and a power combiner having N input ports each operatively connected to one of the N distributed amplifiers. The distributed amplifier can included M stages of amplification by cascading superconducting active devices. The power combiner can include N active elements. The resulting (N[times]M) matrix amplifier can produce signals of high output power, large bandwidth, and low noise. 6 figures.
Matrix computations on mesh arrays
Moreno, J.H.
1989-01-01
This dissertation addresses the systematic derivation of mesh arrays for matrix computations, in particular realizing the algorithm-specific arrays and mapping algorithms onto class-specific arrays. A data-dependency graph-based transformational method is proposed in a design frame work consisting of two stages, namely algorithm regularization and derivation of arrays. The first stage derives the fully-parallel data-dependency graph (FPG) of an algorithm and transforms this graph into a three-dimensional one with unidirectional nearest-neighbor dependencies (a multi-mesh graph MMG). The second stage transforms the MMG into a two-dimensional G-graph, which is realized as an algorithm-specific array or mapped onto a class-specific array. This stage allows the incorporation of implementation restrictions and the evaluation of tradeoffs in properties of cells, as well as the derivation of arrays for fixed-size data and partitioned problems, while performing optimization of specific performance/cost measures. The proposed method is formalized by presenting a sufficient set of transformations and demonstrating the equivalence of graphs obtained from those transformations. Moreover, it is demonstrated that the MMG representation is always possible, due to the characteristics of the operators. The method has been applied to a collection of matrix algorithms, including matrix multiplication, convolution, matrix decompositions, transitive closure, the Faddeev algorithm, and BBA{sup {minus}1}. The examples show that, in addition to the features listed earlier, this method is easy to apply. Moreover, the method is compared with other techniques, concluding that it is advantageous because it meets evaluation criteria and produces more efficient arrays.
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.
Functional Polymer Matrix Fibers
2007-11-02
the carbon nanofibers led to the deterioration of the polymeric cellulose structure. Extensive research on the surface treatment of carbon nanofibers...1 November 2003 - 14-Mar-05 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER FA8655-03-1-3042 Functional Polymer Matrix Fibres 5b. GRANT NUMBER 5c. PROGRAM...MARYLABONE RD LONDON NWl 5TH PERFORMANCE REPORT Project title: Functional polymer matrix fibers Period of performance: 1 November 2003 - 31 October 2004
Aluminum Metal Matrix Composites
Hunt, Warren; Herling, Darrell R.
2004-02-01
Metal matrix composites comprise a relatively wide range of materials defined by the metal matrix, reinforcement type, and reinforcement geometry. In the area of the matrix, most metallic systems have been explored for use in metal matrix composites, including Al, Be, Mg, Ti, Fe, Ni, Co, and Ag. By far, the largest usage is in aluminum matrix composites. From a reinforcement perspective, the materials used are typically ceramics since they provide a very desirable combination of stiffness, strength, and relatively low density. Candidate reinforcement materials include SiC, Al2O3, B4C, TiC, TiB2, graphite, and a number of other ceramics. In addition, there has been work on metallic materials as reinforcements, notably W and steel fibers. The morphology of the reinforcement material is another variable of importance in metal matrix composites. The three major classes of reinforcement morphology are continuous fiber, chopped fiber or whisker, and particulate. Typically, the selection of the reinforcement morphology is determined by the desired property/cost combination. Generally, continuous fiber reinforced MMCs provide the highest properties in the direction of the fiber orientation but are the most expensive. Chopped fiber and whisker reinforced materials can produce significant property improvements in the plane or direction of their orientation, at somewhat lower cost. Particulates provide a comparatively more moderate but isotropic increase in properties and are typically available at the lowest cost. By adding to the three variables of metallic matrix, reinforcement material, and reinforcement morphology the further options of reinforcement volume fraction, orientation, and matrix alloy composition and heat treatment, it is apparent that there is a very wide range of available material combinations and resultant properties. This paper will focus on how MMCs have been applied in specific application areas.
Morris, Christopher G.; Jacques, Nicholas M.; Godfrey, Harry G. W.; Mitra, Tamoghna; Fritsch, Detlev; Lu, Zhenzhong; Murray, Claire A.; Potter, Jonathan; Cobb, Tom M.; Yuan, Fajin
2017-01-01
The identification of preferred binding domains within a host structure provides important insights into the function of materials. State-of-the-art reports mostly focus on crystallographic studies of empty and single component guest-loaded host structures to determine the location of guests. However, measurements of material properties (e.g., adsorption and breakthrough of substrates) are usually performed for a wide range of pressure (guest coverage) and/or using multi-component gas mixtures. Here we report the development of a multifunctional gas dosing system for use in X-ray powder diffraction studies on Beamline I11 at Diamond Light Source. This facility is fully automated and enables in situ crystallographic studies of host structures under (i) unlimited target gas loadings and (ii) loading of multi-component gas mixtures. A proof-of-concept study was conducted on a hydroxyl-decorated porous material MFM-300(VIII) under (i) five different CO2 pressures covering the isotherm range and (ii) the loading of equimolar mixtures of CO2/N2. The study has successfully captured the structural dynamics underpinning CO2 uptake as a function of surface coverage. Moreover, MFM-300(VIII) was incorporated in a mixed matrix membrane (MMM) with PIM-1 in order to evaluate the CO2/N2 separation potential of this material. Gas permeation measurements on the MMM show a great improvement over the bare PIM-1 polymer for CO2/N2 separation based on the ideal selectivity. PMID:28507700
Computing Matrix Representations of Filiform Lie Algebras
NASA Astrophysics Data System (ADS)
Ceballos, Manuel; Núñez, Juan; Tenorio, Ángel F.
In this paper, we compute minimal faithful unitriangular matrix representations of filiform Lie algebras. To do it, we use the nilpotent Lie algebra, g_n, formed of n ×n strictly upper-triangular matrices. More concretely, we search the lowest natural number n such that the Lie algebra g_n contains a given filiform Lie algebra, also computing a representative of this algebra. All the computations in this paper have been done using MAPLE 9.5.
Random Matrix Theory and Econophysics
NASA Astrophysics Data System (ADS)
Rosenow, Bernd
2000-03-01
Random Matrix Theory (RMT) [1] is used in many branches of physics as a ``zero information hypothesis''. It describes generic behavior of different classes of systems, while deviations from its universal predictions allow to identify system specific properties. We use methods of RMT to analyze the cross-correlation matrix C of stock price changes [2] of the largest 1000 US companies. In addition to its scientific interest, the study of correlations between the returns of different stocks is also of practical relevance in quantifying the risk of a given stock portfolio. We find [3,4] that the statistics of most of the eigenvalues of the spectrum of C agree with the predictions of RMT, while there are deviations for some of the largest eigenvalues. We interpret these deviations as a system specific property, e.g. containing genuine information about correlations in the stock market. We demonstrate that C shares universal properties with the Gaussian orthogonal ensemble of random matrices. Furthermore, we analyze the eigenvectors of C through their inverse participation ratio and find eigenvectors with large ratios at both edges of the eigenvalue spectrum - a situation reminiscent of localization theory results. This work was done in collaboration with V. Plerou, P. Gopikrishnan, T. Guhr, L.A.N. Amaral, and H.E Stanley and is related to recent work of Laloux et al.. 1. T. Guhr, A. Müller Groeling, and H.A. Weidenmüller, ``Random Matrix Theories in Quantum Physics: Common Concepts'', Phys. Rep. 299, 190 (1998). 2. See, e.g. R.N. Mantegna and H.E. Stanley, Econophysics: Correlations and Complexity in Finance (Cambridge University Press, Cambridge, England, 1999). 3. V. Plerou, P. Gopikrishnan, B. Rosenow, L.A.N. Amaral, and H.E. Stanley, ``Universal and Nonuniversal Properties of Cross Correlations in Financial Time Series'', Phys. Rev. Lett. 83, 1471 (1999). 4. V. Plerou, P. Gopikrishnan, T. Guhr, B. Rosenow, L.A.N. Amaral, and H.E. Stanley, ``Random Matrix Theory
Bone regeneration using a synthetic matrix containing enamel matrix derivate.
Schneider, David; Weber, Franz E; Hämmerle, Christoph H F; Feloutzis, Andreas; Jung, Ronald E
2011-02-01
The aim of the present study was to test whether the delivery of enamel matrix derivate (EMD) via synthetic polyethylene glycol (PEG)-based hydrogels with and without RGD sequences enhances bone formation in vivo. In each of 10 rabbits, four titanium cylinders were placed on the external cortical bones of their calvaria. The following four treatment modalities were randomly allocated: One of the four cylinders was left empty (control), the other three were filled with a combination of PEG matrix with hydroxyapatite/tricalciumphosphate (HA/TCP) granules and EMD in a concentration of 100 μg/ml (test 1) or 500 μg/ml (test 2) or 500 μg/ml and RGD peptide (test 3). After 8 weeks, the animals were sacrificed and ground sections were obtained for histological analysis. For statistical analysis, the Kruskal-Wallis test was applied (P<0.05). The histomorphometric analysis revealed a statistically larger area fraction of newly formed bone in the EMD 500/RGD group (54.8±14.5%) compared with the control group (28.7±10.3%) and the EMD 500 group (31.2±14.1%) and non-significantly higher area fraction compared with the EMD 100 group (38.2±10.4%). The percentage of mineralized bone showed no statistically significant differences among the four groups. The mean percentage of mineralized bone was 13.6±3.3% in the control group, 14.2±5.8% in the EMD 100 group, 11.69±5.9% in the EMD 500 group and 15.66±5.2% in the EMD 500/RGD group. No statistically significant difference regarding the bone-to-graft contact between the EMD 100 group (23±15.7%), the EMD 500 group (22.2±14.6%) and the EMD 500/RGD group (21.6±8.8%) was observed. The combination of a PEG matrix containing EMD with HA/TCP granules had no effect on the formation of mineralized bone tissue in rabbit calvaria. The addition of RGD peptide to the PEG/EMD 500 combination increased the area fraction of newly formed bone compared with the other treatment groups. Further studies are indicated to study a possible
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)1932-455310.1109/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.
Phase diagram of matrix compressed sensing
NASA Astrophysics Data System (ADS)
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.
Generalized matrix inversion is not harder than matrix multiplication
NASA Astrophysics Data System (ADS)
Petkovic, Marko D.; Stanimirovic, Predrag S.
2009-08-01
Starting from the Strassen method for rapid matrix multiplication and inversion as well as from the recursive Cholesky factorization algorithm, we introduced a completely block recursive algorithm for generalized Cholesky factorization of a given symmetric, positive semi-definite matrix . We used the Strassen method for matrix inversion together with the recursive generalized Cholesky factorization method, and established an algorithm for computing generalized {2,3} and {2,4} inverses. Introduced algorithms are not harder than the matrix-matrix multiplication.
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.
Pan, Feng; Kasiviswanathan, Shiva
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.
NASA Astrophysics Data System (ADS)
Yuan, Haidong; Fung, Chi-Hang Fred
2017-07-01
Various strategies exist in quantum metrology, such as with or without ancillary system, with a fixed or optimized measurement, with or without monitoring the environment, etc. Different set of tools are usually needed for different strategies. In this article, we provide a unified framework for these different settings, in particular we introduce a quantum metrology matrix and show that the precision limits of different settings can all be obtained from the trace or the trace norm of the quantum metrology matrix. Furthermore, the probe state enters into the quantum metrology matrix linearly, which makes the identification of the optimal probe states, one of the main quests in quantum metrology, much more efficient than conventional methods.
Review of "Communication: The Social Matrix of Psychiatry."
ERIC Educational Resources Information Center
Sigmon, Scott B.
"Communication: The Social Matrix of Psychiatry" (J. Ruesch and G. Bateson) is a work that outlines in a more conversational than pedantic way a theory of human communication. The main thrust is to unite two types of organized information: (1) an understanding of the cultural matrix within which the psychiatrist operates; and (2) the nature of…
Review of "Communication: The Social Matrix of Psychiatry."
ERIC Educational Resources Information Center
Sigmon, Scott B.
"Communication: The Social Matrix of Psychiatry" (J. Ruesch and G. Bateson) is a work that outlines in a more conversational than pedantic way a theory of human communication. The main thrust is to unite two types of organized information: (1) an understanding of the cultural matrix within which the psychiatrist operates; and (2) the nature of…
Matrixed business support comparison study.
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.
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.
ERIC Educational Resources Information Center
Grabinger, R. Scott
1989-01-01
Discussion of the preparation of knowledge for problems appropriate for expert systems focuses on relationships among problem attributes and their solutions through the creation of a solution matrix. Two examples are given, one for wine selection and one for decisions that an automobile manufacturer's sales force might have to make. (LRW)
Matrix Embedded Organic Synthesis
NASA Astrophysics Data System (ADS)
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.
NASA Astrophysics Data System (ADS)
Elliott, John
2012-09-01
As part of our 'toolkit' for analysing an extraterrestrial signal, the facility for calculating structural affinity to known phenomena must be part of our core capabilities. Without such a resource, we risk compromising our potential for detection and decipherment or at least causing significant delay in the process. To create such a repository for assessing structural affinity, all known systems (language parameters) need to be structurally analysed to 'place' their 'system' within a relational communication matrix. This will need to include all known variants of language structure, whether 'living' (in current use) or ancient; this must also include endeavours to incorporate yet undeciphered scripts and non-human communication, to provide as complete a picture as possible. In creating such a relational matrix, post-detection decipherment will be assisted by a structural 'map' that will have the potential for 'placing' an alien communication with its nearest known 'neighbour', to assist subsequent categorisation of basic parameters as a precursor to decipherment. 'Universal' attributes and behavioural characteristics of known communication structure will form a range of templates (Elliott, 2001 [1] and Elliott et al., 2002 [2]), to support and optimise our attempt at categorising and deciphering the content of an extraterrestrial signal. Detection of the hierarchical layers, which comprise intelligent, complex communication, will then form a matrix of calculations that will ultimately score affinity through a relational matrix of structural comparison. In this paper we develop the rationales and demonstrate functionality with initial test results.
Matrix product state renormalization
NASA Astrophysics Data System (ADS)
Bal, M.; Rams, M. M.; Zauner, V.; Haegeman, J.; Verstraete, F.
2016-11-01
The truncation or compression of the spectrum of Schmidt values is inherent to the matrix product state (MPS) approximation of one-dimensional quantum ground states. We provide a renormalization group picture by interpreting this compression as an application of Wilson's numerical renormalization group along the imaginary time direction appearing in the path integral representation of the state. The location of the physical index is considered as an impurity in the transfer matrix and static MPS correlation functions are reinterpreted as dynamical impurity correlations. Coarse-graining the transfer matrix is performed using a hybrid variational ansatz based on matrix product operators, combining ideas of MPS and the multiscale entanglement renormalization ansatz. Through numerical comparison with conventional MPS algorithms, we explicitly verify the impurity interpretation of MPS compression, as put forward by V. Zauner et al. [New J. Phys. 17, 053002 (2015), 10.1088/1367-2630/17/5/053002] for the transverse-field Ising model. Additionally, we motivate the conceptual usefulness of endowing MPS with an internal layered structure by studying restricted variational subspaces to describe elementary excitations on top of the ground state, which serves to elucidate a transparent renormalization group structure ingrained in MPS descriptions of ground states.
R-matrix and Mickelsson algebras for orthosymplectic quantum groups
Ashton, Thomas; Mudrov, Andrey
2015-08-15
Let g be a complex orthogonal or symplectic Lie algebra and g′ ⊂ g the Lie subalgebra of rank rk g′ = rk g − 1 of the same type. We give an explicit construction of generators of the Mickelsson algebra Z{sub q}(g, g′) in terms of Chevalley generators via the R-matrix of U{sub q}(g)
Stable Boron Nitride Interphases for Ceramic Matrix Composites
NASA Technical Reports Server (NTRS)
Morscher, Gregory N.
1999-01-01
Ceramic matrix composites (CMC's) require strong fibers for good toughness and weak interphases so that cracks which are formed in the matrix debond and deflect around the fibers. If the fibers are strongly bonded to the matrix, CMC's behave like monolithic ceramics (e.g., a ceramic coffee cup), and when subjected to mechanical loads that induce cracking, such CMC's fail catastrophically. Since CMC's are being developed for high temperature corrosive environments such as the combustor liner for advanced High Speed Civil Transport aircraft, the interphases need to be able to withstand the environment when the matrix cracks.
Nanomechanics of the Cartilage Extracellular Matrix
NASA Astrophysics Data System (ADS)
Han, Lin; Grodzinsky, Alan J.; Ortiz, Christine
2011-08-01
Cartilage is a hydrated biomacromolecular fiber composite located at the ends of long bones that enables proper joint lubrication, articulation, loading, and energy dissipation. Degradation of extracellular matrix molecular components and changes in their nanoscale structure greatly influence the macroscale behavior of the tissue and result in dysfunction with age, injury, and diseases such as osteoarthritis. Here, the application of the field of nanomechanics to cartilage is reviewed. Nanomechanics involves the measurement and prediction of nanoscale forces and displacements, intra- and intermolecular interactions, spatially varying mechanical properties, and other mechanical phenomena existing at small length scales. Experimental nanomechanics and theoretical nanomechanics have been applied to cartilage at varying levels of material complexity, e.g., nanoscale properties of intact tissue, the matrix associated with single cells, biomimetic molecular assemblies, and individual extracellular matrix biomolecules (such as aggrecan, collagen, and hyaluronan). These studies have contributed to establishing a fundamental mechanism-based understanding of native and engineered cartilage tissue function, quality, and pathology.
Hepatocyte Culture in Autologous Decellularized Spleen Matrix
Gao, Rui; Wu, Wanquan; Xiang, Junxi; Lv, Yi; Zheng, Xinglong; Chen, Qian; Wang, Haohua; Wang, Bo; Liu, Zhengwen; Ma, Feng
2015-01-01
abstract Background and Aims: Using decellularized scaffold to reengineer liver tissue is a promising alternative therapy for end-stage liver diseases. Though the decellularized human liver matrix is the ideal scaffold for reconstruction of the liver theoretically, the shortage of liver donors is still an obstacle for potential clinical application. Therefore, an appropriate alternative scaffold is needed. In the present study, we used a tissue engineering approach to prepare a rat decellularized spleen matrix (DSM) and evaluate the effectiveness of this DSM for primary rat hepatocytes culture. Methods: Rat decellularized spleen matrix (DSM) was prepared by perfusion of a series of detergents through spleen vasculature. DSM was characterized by residual DNA and specific extracellular matrix distribution. Thereafter, primary rat hepatocytes were cultured in the DSM in a 3-dimensional dynamic culture system, and liver cell survival and biological functions were evaluated by comparison with 3-dimensional sandwich culture and also with cultured in decellularized liver matrix (DLM). Results: Our research found that DSM did not exhibit any cellular components, but preserved the main extracellular matrix and the intact vasculature evaluated by DNA detection, histology, immunohistochemical staining, vessel corrosion cast and upright metallurgical microscope. Moreover, the method of DSM preparation procedure was relatively simple with high success rate (100%). After seeding primary hepatocytes in DSM, the cultured hepatocytes survived inside DSM with albumin synthesis and urea secretion within 10 d. Additionally, hepatocytes in dynamic culture medium had better biological functions at day 10 than that in sandwich culture. Albumin synthesis was 85.67 ± 6.34 μg/107cell/24h in dynamic culture in DSM compared to 62.43 ± 4.59 μg/107cell/24h in sandwich culture (P < 0.01) and to 87.54 ± 5.25 μg/107cell/24h in DLM culture (P > 0.05); urea release was 32.14 ± 8.62 μg
Generalized matrix models and AGT correspondence at all genera
NASA Astrophysics Data System (ADS)
Bonelli, Giulio; Maruyoshi, Kazunobu; Tanzini, Alessandro; Yagi, Futoshi
2011-07-01
We study generalized matrix models corresponding to n-point Virasoro conformal blocks on Riemann surfaces with arbitrary genus g. Upon AGT correspondence, these describe four dimensional mathcal{N} = 2 SU(2) n+3 g-3 gauge theories with generalized quiver diagrams. We obtain the generalized matrix models from the perturbative evaluation of the Liouville correlation functions and verify the consistency of the description with respect to degenerations of the Riemann surface. Moreover, we derive the Seiberg-Witten curve for the mathcal{N} = 2 gauge theory as the spectral curve of the generalized matrix model, thus providing a check of AGT correspondence at all genera.
Algebraic construction of the Darboux matrix revisited
NASA Astrophysics Data System (ADS)
Cieśliński, Jan L.
2009-10-01
We present algebraic construction of Darboux matrices for 1+1-dimensional integrable systems of nonlinear partial differential equations with a special stress on the nonisospectral case. We discuss different approaches to the Darboux-Bäcklund transformation, based on different λ-dependences of the Darboux matrix: polynomial, sum of partial fractions or the transfer matrix form. We derive symmetric N-soliton formulae in the general case. The matrix spectral parameter and dressing actions in loop groups are also discussed. We describe reductions to twisted loop groups, unitary reductions, the matrix Lax pair for the KdV equation and reductions of chiral models (harmonic maps) to SU(n) and to Grassmann spaces. We show that in the KdV case the nilpotent Darboux matrix generates the binary Darboux transformation. The paper is intended as a review of known results (usually presented in a novel context) but some new results are included as well, e.g., general compact formulae for N-soliton surfaces and linear and bilinear constraints on the nonisospectral Lax pair matrices which are preserved by Darboux transformations.
Phylogenetic Stochastic Mapping Without Matrix Exponentiation
Irvahn, Jan; Minin, Vladimir N.
2014-01-01
Abstract Phylogenetic stochastic mapping is a method for reconstructing the history of trait changes on a phylogenetic tree relating species/organism carrying the trait. State-of-the-art methods assume that the trait evolves according to a continuous-time Markov chain (CTMC) and works well for small state spaces. The computations slow down considerably for larger state spaces (e.g., space of codons), because current methodology relies on exponentiating CTMC infinitesimal rate matrices—an operation whose computational complexity grows as the size of the CTMC state space cubed. In this work, we introduce a new approach, based on a CTMC technique called uniformization, which does not use matrix exponentiation for phylogenetic stochastic mapping. Our method is based on a new Markov chain Monte Carlo (MCMC) algorithm that targets the distribution of trait histories conditional on the trait data observed at the tips of the tree. The computational complexity of our MCMC method grows as the size of the CTMC state space squared. Moreover, in contrast to competing matrix exponentiation methods, if the rate matrix is sparse, we can leverage this sparsity and increase the computational efficiency of our algorithm further. Using simulated data, we illustrate advantages of our MCMC algorithm and investigate how large the state space needs to be for our method to outperform matrix exponentiation approaches. We show that even on the moderately large state space of codons our MCMC method can be significantly faster than currently used matrix exponentiation methods. PMID:24918812
Advances in biomimetic regeneration of elastic matrix structures
Sivaraman, Balakrishnan; Bashur, Chris A.
2012-01-01
Elastin is a vital component of the extracellular matrix, providing soft connective tissues with the property of elastic recoil following deformation and regulating the cellular response via biomechanical transduction to maintain tissue homeostasis. The limited ability of most adult cells to synthesize elastin precursors and assemble them into mature crosslinked structures has hindered the development of functional tissue-engineered constructs that exhibit the structure and biomechanics of normal native elastic tissues in the body. In diseased tissues, the chronic overexpression of proteolytic enzymes can cause significant matrix degradation, to further limit the accumulation and quality (e.g., fiber formation) of newly deposited elastic matrix. This review provides an overview of the role and importance of elastin and elastic matrix in soft tissues, the challenges to elastic matrix generation in vitro and to regenerative elastic matrix repair in vivo, current biomolecular strategies to enhance elastin deposition and matrix assembly, and the need to concurrently inhibit proteolytic matrix disruption for improving the quantity and quality of elastogenesis. The review further presents biomaterial-based options using scaffolds and nanocarriers for spatio-temporal control over the presentation and release of these biomolecules, to enable biomimetic assembly of clinically relevant native elastic matrix-like superstructures. Finally, this review provides an overview of recent advances and prospects for the application of these strategies to regenerating tissue-type specific elastic matrix structures and superstructures. PMID:23355960
NASA Astrophysics Data System (ADS)
Edelman, Alan; Rao, N. Raj
Random matrix theory is now a big subject with applications in many disciplines of science, engineering and finance. This article is a survey specifically oriented towards the needs and interests of a numerical analyst. This survey includes some original material not found anywhere else. We include the important mathematics which is a very modern development, as well as the computational software that is transforming the theory into useful practice.
NASA Astrophysics Data System (ADS)
Mortensen, Andreas; Llorca, Javier
2010-08-01
In metal matrix composites, a metal is combined with another, often nonmetallic, phase to produce a novel material having attractive engineering attributes of its own. A subject of much research in the 1980s and 1990s, this class of materials has, in the past decade, increased significantly in variety. Copper matrix composites, layered composites, high-conductivity composites, nanoscale composites, microcellular metals, and bio-derived composites have been added to a palette that, ten years ago, mostly comprised ceramic fiber- or particle-reinforced light metals together with some well-established engineering materials, such as WC-Co cermets. At the same time, research on composites such as particle-reinforced aluminum, aided by novel techniques such as large-cell 3-D finite element simulation or computed X-ray microtomography, has served as a potent vehicle for the elucidation of the mechanics of high-contrast two-phase elastoplastic materials, with implications that range well beyond metal matrix composites.
Hypercube matrix computation task
NASA Technical Reports Server (NTRS)
Calalo, Ruel H.; Imbriale, William A.; Jacobi, Nathan; Liewer, Paulett C.; Lockhart, Thomas G.; Lyzenga, Gregory A.; Lyons, James R.; Manshadi, Farzin; Patterson, Jean E.
1988-01-01
A major objective of the Hypercube Matrix Computation effort at the Jet Propulsion Laboratory (JPL) is to investigate the applicability of a parallel computing architecture to the solution of large-scale electromagnetic scattering problems. Three scattering analysis codes are being implemented and assessed on a JPL/California Institute of Technology (Caltech) Mark 3 Hypercube. The codes, which utilize different underlying algorithms, give a means of evaluating the general applicability of this parallel architecture. The three analysis codes being implemented are a frequency domain method of moments code, a time domain finite difference code, and a frequency domain finite elements code. These analysis capabilities are being integrated into an electromagnetics interactive analysis workstation which can serve as a design tool for the construction of antennas and other radiating or scattering structures. The first two years of work on the Hypercube Matrix Computation effort is summarized. It includes both new developments and results as well as work previously reported in the Hypercube Matrix Computation Task: Final Report for 1986 to 1987 (JPL Publication 87-18).
Primitive ultrafine matrix in ordinary chondrites
NASA Technical Reports Server (NTRS)
Rambaldi, E. R.; Fredriksson, B. J.; Fredriksson, K.
1981-01-01
Ultrafine matrix material has been concentrated by sieving and filtering disaggregated samples of six ordinary chondrites of different classes. This component(s), 'Holy Smoke' (HS), is enriched in both volatile, e.g. Na, K, Zn, Sb, and Pb, as well as refractory elements, e.g. W and REE; however, the element ratios vary greatly among the different chondrites. SEM studies show that HS contains fragile crystals, differing in composition, and apparently in gross disequilibrium not only among themselves but also with the major mineral phases and consequently thermodynamic equilibration did not occur. Thus HS must have originated from impacting bodies and/or was inherent in the 'primitive' regolith. Subsequent impact brecciation and reheating appears to have altered, to varying degrees, the original composition of this ultrafine matrix material. Recent 'cosmic dust' studies may indicate that HS still exists in the solar system. Survival of such delicate material must be considered in all theories for the origin of chondrites.
Thornton, K J; Kamange-Sollo, E; White, M E; Dayton, W R
2015-09-01
Implanting cattle with steroids significantly enhances feed efficiency, rate of gain, and muscle growth. However, the mechanisms responsible for these improvements in muscle growth have not been fully elucidated. Trenbolone acetate (TBA), a testosterone analog, has been shown to increase proliferation rate in bovine satellite cell (BSC) cultures. The classical genomic actions of testosterone have been well characterized; however, our results indicate that TBA may also initiate a quicker, nongenomic response that involves activation of G protein-coupled receptors (GPCR) resulting in activation of matrix metalloproteinases 2 and 9 (MMP2 and MMP9) that release membrane-bound heparin-binding epidermal growth factor-like growth factor (hbEGF), which then binds to and activates the epidermal growth factor receptor (EGFR) and/or erbB2. Furthermore, the EGFR has been shown to regulate expression of the IGF-1 receptor (IGF-1R), which is well known for its role in modulating muscle growth. To determine whether this nongenomic pathway is potentially involved in TBA-stimulated BSC proliferation, we analyzed the effects of treating BSC with guanosine 5'-O-2-thiodiphosphate (GDPβS), an inhibitor of all GPCR; a MMP2 and MMP9 inhibitor (MMPI); CRM19, a specific inhibitor of hbEGF; AG1478, a specific EGFR tyrosine kinase inhibitor; AG879, a specific erbB2 kinase inhibitor; and AG1024, an IGF-1R tyrosine kinase inhibitor on TBA-stimulated proliferation rate (H-thymidine incorporation). Assays were replicated at least 9 times for each inhibitor experiment using BSC cultures obtained from at least 3 different animals. Bovine satellite cell cultures were obtained from yearling steers that had no previous exposure to androgenic or estrogenic compounds. As expected, BSC cultures treated with 10 n TBA showed ( < 0.05) increased proliferation rate when compared with control cultures. Additionally, treatment with 5 ng hbEGF/mL stimulated proliferation in BSC cultures ( < 0.05). Treatment
On the Matrix Exponential Function
ERIC Educational Resources Information Center
Hou, Shui-Hung; Hou, Edwin; Pang, Wan-Kai
2006-01-01
A novel and simple formula for computing the matrix exponential function is presented. Specifically, it can be used to derive explicit formulas for the matrix exponential of a general matrix A satisfying p(A) = 0 for a polynomial p(s). It is ready for use in a classroom and suitable for both hand as well as symbolic computation.
On the Matrix Exponential Function
ERIC Educational Resources Information Center
Hou, Shui-Hung; Hou, Edwin; Pang, Wan-Kai
2006-01-01
A novel and simple formula for computing the matrix exponential function is presented. Specifically, it can be used to derive explicit formulas for the matrix exponential of a general matrix A satisfying p(A) = 0 for a polynomial p(s). It is ready for use in a classroom and suitable for both hand as well as symbolic computation.
Alcantara, Ethel H; Lomeda, Ria-Ann R; Feldmann, Joerg; Nixon, Graeme F; Beattie, John H; Kwun, In-Sook
2011-10-01
Zinc is implicated as an activator for bone formation, however, its influence on bone calcification has not been reported. This study examined how zinc regulates the bone matrix calcification in osteoblasts. Two osteoblastic MC3T3-E1 cell subclones (SC 4 and SC 24 as high and low osteogenic differentiation, respectively) were cultured in normal osteogenic (OSM), Zinc deficient (Zn-, 1 μM), or adequate (Zn+, 15 μM) media up to 20 days. Cells (SC 4) were also supplemented with (50 μg/mL) or no ascorbic acid (AA) in combination with Zinc treatment. Zn- decreased collagen synthesis and matrix accumulation. Although AA is essential for collagen formation, its supplementation could not compensate for Zinc deficiency-induced detrimental effects on extracellular matrix mineralization. Zn- also decreased the medium and cell layer alkaline phosphatase ALP activity. This decreased ALP activity might cause the decrease of Pi accumulation in response to Zn-, as measured by von Kossa staining. Ca deposition in cell layers, measured by Alizarin red S staining, was also decreased by Zn(-) . Our findings suggest that zinc deprivation inhibits extracellular matrix calcification in osteoblasts by decreasing the synthesis and activity of matrix proteins, type I collagen and ALP, and decreasing Ca and Pi accumulation. Therefore zinc deficiency can be considered as risk factor for poor extracellular matrix calcification. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
The cellulose resource matrix.
Keijsers, Edwin R P; Yılmaz, Gülden; van Dam, Jan E G
2013-03-01
The emerging biobased economy is causing shifts from mineral fossil oil based resources towards renewable resources. Because of market mechanisms, current and new industries utilising renewable commodities, will attempt to secure their supply of resources. Cellulose is among these commodities, where large scale competition can be expected and already is observed for the traditional industries such as the paper industry. Cellulose and lignocellulosic raw materials (like wood and non-wood fibre crops) are being utilised in many industrial sectors. Due to the initiated transition towards biobased economy, these raw materials are intensively investigated also for new applications such as 2nd generation biofuels and 'green' chemicals and materials production (Clark, 2007; Lange, 2007; Petrus & Noordermeer, 2006; Ragauskas et al., 2006; Regalbuto, 2009). As lignocellulosic raw materials are available in variable quantities and qualities, unnecessary competition can be avoided via the choice of suitable raw materials for a target application. For example, utilisation of cellulose as carbohydrate source for ethanol production (Kabir Kazi et al., 2010) avoids the discussed competition with easier digestible carbohydrates (sugars, starch) deprived from the food supply chain. Also for cellulose use as a biopolymer several different competing markets can be distinguished. It is clear that these applications and markets will be influenced by large volume shifts. The world will have to reckon with the increase of competition and feedstock shortage (land use/biodiversity) (van Dam, de Klerk-Engels, Struik, & Rabbinge, 2005). It is of interest - in the context of sustainable development of the bioeconomy - to categorize the already available and emerging lignocellulosic resources in a matrix structure. When composing such "cellulose resource matrix" attention should be given to the quality aspects as well as to the available quantities and practical possibilities of processing the
Supported Molecular Matrix Electrophoresis.
Matsuno, Yu-Ki; Kameyama, Akihiko
2015-01-01
Mucins are difficult to separate using conventional gel electrophoresis methods such as SDS-PAGE and agarose gel electrophoresis, owing to their large size and heterogeneity. On the other hand, cellulose acetate membrane electrophoresis can separate these molecules, but is not compatible with glycan analysis. Here, we describe a novel membrane electrophoresis technique, termed "supported molecular matrix electrophoresis" (SMME), in which a porous polyvinylidene difluoride (PVDF) membrane filter is used to achieve separation. This description includes the separation, visualization, and glycan analysis of mucins with the SMME technique.
Semiclassical integrable matrix elements
Morehead, J.J.
1996-03-01
A semiclassical expression for matrix elements of an arbitrary operator with respect to the eigenstates of an integrable Hamiltonian is derived. This is essentially the Heisenberg correspondence principle, and it is shown via the Weyl correspondence that the approximation is valid through the lowest two orders in {h_bar}. The result is used to prove that an asymptotic form of the Clebsch-Gordan coefficients for two large and one small angular momenta is valid through two orders. {copyright} {ital 1996 The American Physical Society.}
Statistical meaning of the differential Mueller matrix of depolarizing homogeneous media.
Ossikovski, Razvigor; Arteaga, Oriol
2014-08-01
By applying the statistical definition of a depolarizing Mueller matrix we formally derive and physically interpret the differential matrix of a depolarizing homogeneous medium. The depolarization phenomenon being a direct consequence of the fluctuations of the six elementary polarization properties of the medium, the differential matrix contains the mean values and the variances of the properties, thus fully describing those from a statistical viewpoint. Similarly, the reduced coherency matrix associated with the G-symmetric component of the differential matrix has an immediate physical interpretation as being the covariance matrix of the three basic groups of polarization properties. The formal developments are illustrated on experimental examples.
Infinite dimensional matrix algebras
NASA Astrophysics Data System (ADS)
Bordemann, M.; Hoppe, J.; Schaller, P.
1989-11-01
To each (finite dimensional) Lie algebra g we associate a class L λ(g) of infinite dimensional Lie algebras, induced by representations D λ(g). We show that in the case of sl(2, C) one obtains a series of pairwise non-isomorphic infinite dimensional Lie algebras depending continuously on a complex parameter λ. We connect this method with previous results on the relation between Diff AS 2 and su( N), and comment on a recent conjecture concerning higher spin algebras, and (2 + 1)-dimensional gravity.
2014-09-26
in Metal Matrix Composites Contract No. N00014-84-C-0413 Submitted to Dr. Steve G. Fishman Office of Naval Research Mohan S. Misra Program Manager...Mechanisms in Metal Matrix Composites." 2.0 INTRODUCTION Metal matrix composites are candidate structural materials for space applications. Large structures...damping capacity of the structural material is a significant parameter. If metal matrix composites are to be used for space structures; their
Ceramic matrix and resin matrix composites: A comparison
NASA Technical Reports Server (NTRS)
Hurwitz, Frances I.
1987-01-01
The underlying theory of continuous fiber reinforcement of ceramic matrix and resin matrix composites, their fabrication, microstructure, physical and mechanical properties are contrasted. The growing use of organometallic polymers as precursors to ceramic matrices is discussed as a means of providing low temperature processing capability without the fiber degradation encountered with more conventional ceramic processing techniques. Examples of ceramic matrix composites derived from particulate-filled, high char yield polymers and silsesquioxane precursors are provided.
Matrix membranes and integrability
Zachos, C.; Fairlie, D.; Curtright, T.
1997-06-01
This is a pedagogical digest of results reported in Curtright, Fairlie, {ampersand} Zachos 1997, and an explicit implementation of Euler`s construction for the solution of the Poisson Bracket dual Nahm equation. But it does not cover 9 and 10-dimensional systems, and subsequent progress on them Fairlie 1997. Cubic interactions are considered in 3 and 7 space dimensions, respectively, for bosonic membranes in Poisson Bracket form. Their symmetries and vacuum configurations are explored. Their associated first order equations are transformed to Nahm`s equations, and are hence seen to be integrable, for the 3-dimensional case, by virtue of the explicit Lax pair provided. Most constructions introduced also apply to matrix commutator or Moyal Bracket analogs.
Matrix metalloproteinase inhibitors.
Wojtowicz-Praga, S M; Dickson, R B; Hawkins, M J
1997-01-01
The matrix metalloproteinases (MMPs) are a family of at least fifteen secreted and membrane-bound zinc-endopeptidases. Collectively, these enzymes can degrade all of the components of the extracellular matrix, including fibrallar and non-fibrallar collagens, fibronectin, laminin and basement membrane glycoproteins. MMPs are thought to be essential for the diverse invasive processes of angiogenesis and tumor metastasis. Numerous studies have shown that there is a close association between expression of various members of the MMP family by tumors and their proliferative and invasive behavior and metastatic potential. In some of human cancers a positive correlation has also been demonstrated between the intensity of new blood vessel growth (angiogenesis) and the likelihood of developing metastases. Thus, control of MMP activity in these two different contexts has generated considerable interest as a possible therapeutic target. The tissue inhibitors of metalloproteinases (TIMPs) are naturally occurring proteins that specifically inhibit matrix metalloproteinases, thus maintaining balance between matrix destruction and formation. An imbalance between MMPs and the associated TIMPs may play a significant role in the invasive phenotype of malignant tumors. TIMP-1 has been shown to inhibit tumor-induced angiogenesis in experimental systems. These findings raised the possibility of using an agent that affects expression or activity of MMPs as an anti-cancer therapy. TIMPs are probably not suitable for pharmacologic applications due to their short half-life in vivo. Batimastat (BB-94) and marimastat (BB-2516) are synthetic, low-molecular weight MMP inhibitors. They have a collagen-mimicking hydroxamate structure, which facilitates chelation of the zinc ion in the active site of the MMPs. These compounds inhibit MMPs potently and specifically. Batimastat was the first synthetic MMP inhibitor studied in humans with advanced malignancies, but its usefulness has been limited by
Hyaluronan: A Matrix Component
NASA Astrophysics Data System (ADS)
Rügheimer, Louise
2008-09-01
The glucosaminoglycan hyaluronan is a key component of the extracellular matrix. It is a large, negatively charged molecule that can act as an ion exchange reservoir for positive ions. Hyaluronan is involved in renomedullary water handling through its water-binding capacity. In the renal medulla, the main source for hyaluronan production is the renomedullary interstitial cells. Hyaluronan synthases are found in the inner part of the plasma membrane and polymerize hyaluronan chains which are extruded into the extracellular space. Hyaluronidases are a family of enzymes involved in the degradation of hyaluronan. They have a wide range of properties, including differences in size, inhibitor sensitivities, catalytic mechanisms, substrate specificities and pH optima.
NASA Astrophysics Data System (ADS)
Frahm, K. M.; Shepelyansky, D. L.
2012-10-01
We construct the Google matrix of the entire Twitter network, dated by July 2009, and analyze its spectrum and eigenstate properties including the PageRank and CheiRank vectors and 2DRanking of all nodes. Our studies show much stronger inter-connectivity between top PageRank nodes for the Twitter network compared to the networks of Wikipedia and British Universities studied previously. Our analysis allows to locate the top Twitter users which control the information flow on the network. We argue that this small fraction of the whole number of users, which can be viewed as the social network elite, plays the dominant role in the process of opinion formation on the network.
Mixed Mode Matrix Multiplication
Meng-Shiou Wu; Srinivas Aluru; Ricky A. Kendall
2004-09-30
In modern clustering environments where the memory hierarchy has many layers (distributed memory, shared memory layer, cache,...), an important question is how to fully utilize all available resources and identify the most dominant layer in certain computations. When combining algorithms on all layers together, what would be the best method to get the best performance out of all the resources we have? Mixed mode programming model that uses thread programming on the shared memory layer and message passing programming on the distributed memory layer is a method that many researchers are using to utilize the memory resources. In this paper, they take an algorithmic approach that uses matrix multiplication as a tool to show how cache algorithms affect the performance of both shared memory and distributed memory algorithms. They show that with good underlying cache algorithm, overall performance is stable. When underlying cache algorithm is bad, superlinear speedup may occur, and an increasing number of threads may also improve performance.
Hastings, Matthew B
2009-01-01
We show how to combine the light-cone and matrix product algorithms to simulate quantum systems far from equilibrium for long times. For the case of the XXZ spin chain at {Delta} = 0.5, we simulate to a time of {approx} 22.5. While part of the long simulation time is due to the use of the light-cone method, we also describe a modification of the infinite time-evolving bond decimation algorithm with improved numerical stability, and we describe how to incorporate symmetry into this algorithm. While statistical sampling error means that we are not yet able to make a definite statement, the behavior of the simulation at long times indicates the appearance of either 'revivals' in the order parameter as predicted by Hastings and Levitov (e-print arXiv:0806.4283) or of a distinct shoulder in the decay of the order parameter.
Calculation of the heavy-hadron axial couplings g1, g2, and g3 using lattice QCD
Will Detmold, David Lin, Stefan Meinel
2012-06-01
In a recent paper [arXiv:1109.2480] we have reported on a lattice QCD calculation of the heavy-hadron axial couplings g{sub 1}, g{sub 2}, and g{sub 3}. These quantities are low-energy constants of heavy-hadron chiral perturbation theory (HH{chi}PT) and are related to the B*B{pi}, {Sigma}{sub b}*{Sigma}{sub b}{pi}, and {Sigma}{sub b}{sup (*)}{Lambda}{sub b}{pi} couplings. In the following, we discuss important details of the calculation and give further results. To determine the axial couplings, we explicitly match the matrix elements of the axial current in QCD with the corresponding matrix elements in HH{chi}PT. We construct the ratios of correlation functions used to calculate the matrix elements in lattice QCD, and study the contributions from excited states. We present the complete numerical results and discuss the data analysis in depth. In particular, we demonstrate the convergence of SU(4|2) HH{chi}PT for the axial current matrix elements at pion masses up to about 400 MeV and show the impact of the nonanalytic loop contributions. Finally, we present additional predictions for strong and radiative decay widths of charm and bottom baryons.
Lectures on Matrix Field Theory
NASA Astrophysics Data System (ADS)
Ydri, Badis
The subject of matrix field theory involves matrix models, noncommutative geometry, fuzzy physics and noncommutative field theory and their interplay. In these lectures, a lot of emphasis is placed on the matrix formulation of noncommutative and fuzzy spaces, and on the non-perturbative treatment of the corresponding field theories. In particular, the phase structure of noncommutative $\\phi^4$ theory is treated in great detail, and an introduction to noncommutative gauge theory is given.
Carbon Nanotube Aluminum Matrix Composites
2010-08-01
replacement of air space with the polymer matrix. A similar affinity is not known to exist between CNTs and aluminum , where the wetting angle between...Carbon Nanotube Aluminum Matrix Composites by Brent J. Carey, Jerome T. Tzeng, and Shashi Karna ARL-TR-5252 August 2010...Nanotube Aluminum Matrix Composites Brent J. Carey, Jerome T. Tzeng, and Shashi Karna Weapons and Materials Research Directorate, ARL
Andric, I.; Jonke, L.; Jurman, D.; Nielsen, H. B.
2008-06-15
We discuss a dynamical matrix model by which probability distribution is associated with Gaussian ensembles from random matrix theory. We interpret the matrix M as a Hamiltonian representing interaction of a bosonic system with a single fermion. We show that a system of second-quantized fermions influences the ground state of the whole system by producing a gap between the highest occupied eigenvalue and the lowest unoccupied eigenvalue.
Excited State Effects in Nucleon Matrix Element Calculations
Constantia Alexandrou, Martha Constantinou, Simon Dinter, Vincent Drach, Karl Jansen, Theodoros Leontiou, Dru B Renner
2011-12-01
We perform a high-statistics precision calculation of nucleon matrix elements using an open sink method allowing us to explore a wide range of sink-source time separations. In this way the influence of excited states of nucleon matrix elements can be studied. As particular examples we present results for the nucleon axial charge g{sub A} and for the first moment of the isovector unpolarized parton distribution x{sub u-d}. In addition, we report on preliminary results using the generalized eigenvalue method for nucleon matrix elements. All calculations are performed using N{sub f} = 2+1+1 maximally twisted mass Wilson fermions.
NASA Astrophysics Data System (ADS)
Dorey, Nick; Tong, David; Turner, Carl
2016-08-01
We study a U( N) gauged matrix quantum mechanics which, in the large N limit, is closely related to the chiral WZW conformal field theory. This manifests itself in two ways. First, we construct the left-moving Kac-Moody algebra from matrix degrees of freedom. Secondly, we compute the partition function of the matrix model in terms of Schur and Kostka polynomials and show that, in the large N limit, it coincides with the partition function of the WZW model. This same matrix model was recently shown to describe non-Abelian quantum Hall states and the relationship to the WZW model can be understood in this framework.
Analytical techniques for instrument design - matrix methods
Robinson, R.A.
1997-09-01
We take the traditional Cooper-Nathans approach, as has been applied for many years for steady-state triple-axis spectrometers, and consider its generalisation to other inelastic scattering spectrometers. This involves a number of simple manipulations of exponentials of quadratic forms. In particular, we discuss a toolbox of matrix manipulations that can be performed on the 6- dimensional Cooper-Nathans matrix: diagonalisation (Moller-Nielsen method), coordinate changes e.g. from ({Delta}k{sub I},{Delta}k{sub F} to {Delta}E, {Delta}Q & 2 dummy variables), integration of one or more variables (e.g. over such dummy variables), integration subject to linear constraints (e.g. Bragg`s Law for analysers), inversion to give the variance-covariance matrix, and so on. We show how these tools can be combined to solve a number of important problems, within the narrow-band limit and the gaussian approximation. We will argue that a generalised program that can handle multiple different spectrometers could (and should) be written in parallel to the Monte-Carlo packages that are becoming available. We will also discuss the complementarity between detailed Monte-Carlo calculations and the approach presented here. In particular, Monte-Carlo methods traditionally simulate the real experiment as performed in practice, given a model scattering law, while the Cooper-Nathans method asks the inverse question: given that a neutron turns up in a particular spectrometer configuration (e.g. angle and time of flight), what is the probability distribution of possible scattering events at the sample? The Monte-Carlo approach could be applied in the same spirit to this question.
Studying genetic code by a matrix approach.
Crowder, Tanner; Li, Chi-Kwong
2010-05-01
Following Petoukhov and his collaborators, we use two length n zero-one sequences, alpha and beta, to represent a length n genetic sequence (alpha/beta) so that the columns of (alpha/beta) have the following correspondence with the nucleotides: C ~ (0/0), U ~ (1/0), G ~ (1/1), A ~ (0/1). Using the Gray code ordering to arrange alpha and beta, we build a 2(n) x 2(n) matrix C(n) including all the 4(n) length n genetic sequences. Furthermore, we use the Hamming distance of alpha and beta to construct a 2(n) x 2(n) matrix D(n). We explore structures of these matrices, refine the results in earlier papers, and propose new directions for further research.
Matrix market: a web resource for test matrix collection
Boisvert, R.F.; Pozo, R.; Remington, K.; Barrett, R.F.; Dongarra, J.J. /
1996-05-30
We describe a repository of data for the testing of numerical algorithms and mathematical software for matrix computations. The repository is designed to accommodate both dense and sparse matrices, as well as software to generate matrices. It has been seeded with the well known Harwell-Boeing sparse matrix collection. The raw data files have been augmented with an integrated World Wide Web interface which describes the matrices in the collection quantitatively and visually, For example, each matrix has a Web page which details its attributes, graphically depicts its sparsity pattern, and provides access to the matrix itself in several formats. In addition, a search mechanism is included which allows retrieval of matrices based on a variety of attributes, such as type and size, as well as through free-text search in abstracts. The URL is http://math.nist.gov/MatrixMarket.
Ceramic matrix composite article and process of fabricating a ceramic matrix composite article
Cairo, Ronald Robert; DiMascio, Paul Stephen; Parolini, Jason Robert
2016-01-12
A ceramic matrix composite article and a process of fabricating a ceramic matrix composite are disclosed. The ceramic matrix composite article includes a matrix distribution pattern formed by a manifold and ceramic matrix composite plies laid up on the matrix distribution pattern, includes the manifold, or a combination thereof. The manifold includes one or more matrix distribution channels operably connected to a delivery interface, the delivery interface configured for providing matrix material to one or more of the ceramic matrix composite plies. The process includes providing the manifold, forming the matrix distribution pattern by transporting the matrix material through the manifold, and contacting the ceramic matrix composite plies with the matrix material.
Calkins, Noel C.
1991-01-01
An armor system which utilizes glass. A plurality of constraint cells are mounted on a surface of a substrate, which is metal armor plate or a similar tough material, such that the cells almost completely cover the surface of the substrate. Each constraint cell has a projectile-receiving wall parallel to the substrate surface and has sides which are perpendicular to and surround the perimeter of the receiving wall. The cells are mounted such that, in one embodiment, the substrate surface serves as a sixth side or closure for each cell. Each cell has inside of it a plate, termed the front plate, which is parallel to and in contact with substantially all of the inside surface of the receiving wall. The balance of each cell is completely filled with a projectile-abrading material consisting of glass and a ceramic material and, in certain embodiments, a polymeric material. The glass may be in monolithic form or particles of ceramic may be dispersed in a glass matrix. The ceramic material may be in monolithic form or may be in the form of particles dispersed in glass or dispersed in said polymer.
Hypercube matrix computation task
NASA Technical Reports Server (NTRS)
Calalo, R.; Imbriale, W.; Liewer, P.; Lyons, J.; Manshadi, F.; Patterson, J.
1987-01-01
The Hypercube Matrix Computation (Year 1986-1987) task investigated the applicability of a parallel computing architecture to the solution of large scale electromagnetic scattering problems. Two existing electromagnetic scattering codes were selected for conversion to the Mark III Hypercube concurrent computing environment. They were selected so that the underlying numerical algorithms utilized would be different thereby providing a more thorough evaluation of the appropriateness of the parallel environment for these types of problems. The first code was a frequency domain method of moments solution, NEC-2, developed at Lawrence Livermore National Laboratory. The second code was a time domain finite difference solution of Maxwell's equations to solve for the scattered fields. Once the codes were implemented on the hypercube and verified to obtain correct solutions by comparing the results with those from sequential runs, several measures were used to evaluate the performance of the two codes. First, a comparison was provided of the problem size possible on the hypercube with 128 megabytes of memory for a 32-node configuration with that available in a typical sequential user environment of 4 to 8 megabytes. Then, the performance of the codes was anlyzed for the computational speedup attained by the parallel architecture.
Hybridized polymer matrix composites
NASA Technical Reports Server (NTRS)
House, E. E.; Hoggatt, J. T.; Symonds, W. A.
1980-01-01
The extent to which graphite fibers are released from resin matrix composites that are exposed to fire and impact conditions was determined. Laboratory simulations of those conditions that could exist in the event of an aircraft crash and burn situation were evaluated. The effectiveness of various hybridizing concepts in preventing this release of graphite fibers were also evaluated. The baseline (i.e., unhybridized) laminates examined were prepared from commercially available graphite/epoxy, graphite/polyimide, and graphite/phenolic materials. Hybridizing concepts investigated included resin fillers, laminate coatings, resin blending, and mechanical interlocking of the graphite reinforcement. The baseline and hybridized laminates' mechanical properties, before and after isothermal and humidity aging, were also compared. It was found that a small amount of graphite fiber was released from the graphite/epoxy laminates during the burn and impact conditions used in this program. However, the extent to which the fibers were released is not considered a severe enough problem to preclude the use of graphite reinforced composites in civil aircraft structure. It also was found that several hybrid concepts eliminated this fiber release. Isothermal and humidity aging did not appear to alter the fiber release tendencies.
ERIC Educational Resources Information Center
Jairam, Dharmananda; Kiewra, Kenneth A.; Kauffman, Douglas F.; Zhao, Ruomeng
2012-01-01
This study investigated how best to study a matrix. Fifty-three participants studied a matrix topically (1 column at a time), categorically (1 row at a time), or in a unified way (all at once). Results revealed that categorical and unified study produced higher: (a) performance on relationship and fact tests, (b) study material satisfaction, and…
Matrix Methods to Analytic Geometry.
ERIC Educational Resources Information Center
Bandy, C.
1982-01-01
The use of basis matrix methods to rotate axes is detailed. It is felt that persons who have need to rotate axes often will find that the matrix method saves considerable work. One drawback is that most students first learning to rotate axes will not yet have studied linear algebra. (MP)
Cascade sample matrix inversion arrays
NASA Astrophysics Data System (ADS)
Hanson, Timothy; Essman, Joseph
It is shown that if a narrowband adaptive array is partitioned and processed as a cascade of adaptive arrays, computational complexity is reduced and performance is only slightly degraded. The sample matrix inversion (SMI) and covariance matrix estimation are discussed. Cascade SMI complexity is examined. Simulation results are presented.
ERIC Educational Resources Information Center
Jairam, Dharmananda; Kiewra, Kenneth A.; Kauffman, Douglas F.; Zhao, Ruomeng
2012-01-01
This study investigated how best to study a matrix. Fifty-three participants studied a matrix topically (1 column at a time), categorically (1 row at a time), or in a unified way (all at once). Results revealed that categorical and unified study produced higher: (a) performance on relationship and fact tests, (b) study material satisfaction, and…
Micromechanics for ceramic matrix composites
NASA Technical Reports Server (NTRS)
Murthy, P. L. N.; Chamis, C. C.
1991-01-01
The fiber substructuring concepts and the micromechanics equations that are embedded in the Ceramic Matrix Composite Analyzer (CEMCAN) computer code are described as well as the code itself, its current features and capabilities, and some examples to demonstrate the code's versatility. The methodology is equally applicable to metal matrix and polymer matrix composites. The prediction of ply mechanical and thermal properties agree very well with the existing models in the Integrated Composite Analyzer and the Ceramic Matrix Composite Analyzer, lending credence to the fiber substructuring approach. Fiber substructuring can capture greater local detail than conventional unit-cell-based micromechanical theories. It offers promise in simulating complex aspects of micromechanics in ceramic matrix composites.
Making recombinant extracellular matrix proteins.
Ruggiero, Florence; Koch, Manuel
2008-05-01
A variety of approaches to understand extracellular matrix protein structure and function require production of recombinant proteins. Moreover, the expression of heterologous extracellular matrix proteins, in particular collagens, using the recombinant technology is of major interest to the biomedical industry. Although extracellular matrix proteins are large, modular and often multimeric, most of them have been successfully produced in various expression systems. This review provides important factors, including the design of the construct, the cloning strategies, the expression vectors, the transfection method and the host cell systems, to consider in choosing a reliable and cost-effective way to make recombinant extracellular matrix proteins. Advantages and drawbacks of each system have been appraised. Protocols that may ease efficient recombinant production of extracellular matrix are described. Emphasis is placed on the recombinant collagen production. Members of the collagen superfamily exhibit specific structural features and generally require complex post-translational modifications to retain full biological activity that make more arduous their recombinant production.
MatrixDB, the extracellular matrix interaction database
Chautard, Emilie; Fatoux-Ardore, Marie; Ballut, Lionel; Thierry-Mieg, Nicolas; Ricard-Blum, Sylvie
2011-01-01
MatrixDB (http://matrixdb.ibcp.fr) is a freely available database focused on interactions established by extracellular proteins and polysaccharides. Only few databases report protein–polysaccharide interactions and, to the best of our knowledge, there is no other database of extracellular interactions. MatrixDB takes into account the multimeric nature of several extracellular protein families for the curation of interactions, and reports interactions with individual polypeptide chains or with multimers, considered as permanent complexes, when appropriate. MatrixDB is a member of the International Molecular Exchange consortium (IMEx) and has adopted the PSI-MI standards for the curation and the exchange of interaction data. MatrixDB stores experimental data from our laboratory, data from literature curation, data imported from IMEx databases, and data from the Human Protein Reference Database. MatrixDB is focused on mammalian interactions, but aims to integrate interaction datasets of model organisms when available. MatrixDB provides direct links to databases recapitulating mutations in genes encoding extracellular proteins, to UniGene and to the Human Protein Atlas that shows expression and localization of proteins in a large variety of normal human tissues and cells. MatrixDB allows researchers to perform customized queries and to build tissue- and disease-specific interaction networks that can be visualized and analyzed with Cytoscape or Medusa. PMID:20852260
MatrixDB, the extracellular matrix interaction database.
Chautard, Emilie; Fatoux-Ardore, Marie; Ballut, Lionel; Thierry-Mieg, Nicolas; Ricard-Blum, Sylvie
2011-01-01
MatrixDB (http://matrixdb.ibcp.fr) is a freely available database focused on interactions established by extracellular proteins and polysaccharides. Only few databases report protein-polysaccharide interactions and, to the best of our knowledge, there is no other database of extracellular interactions. MatrixDB takes into account the multimeric nature of several extracellular protein families for the curation of interactions, and reports interactions with individual polypeptide chains or with multimers, considered as permanent complexes, when appropriate. MatrixDB is a member of the International Molecular Exchange consortium (IMEx) and has adopted the PSI-MI standards for the curation and the exchange of interaction data. MatrixDB stores experimental data from our laboratory, data from literature curation, data imported from IMEx databases, and data from the Human Protein Reference Database. MatrixDB is focused on mammalian interactions, but aims to integrate interaction datasets of model organisms when available. MatrixDB provides direct links to databases recapitulating mutations in genes encoding extracellular proteins, to UniGene and to the Human Protein Atlas that shows expression and localization of proteins in a large variety of normal human tissues and cells. MatrixDB allows researchers to perform customized queries and to build tissue- and disease-specific interaction networks that can be visualized and analyzed with Cytoscape or Medusa.
NASA Astrophysics Data System (ADS)
Horne, Richard B.; Kersten, Tobias; Glauert, Sarah A.; Meredith, Nigel P.; Boscher, Daniel; Sicard, Angelica; Maget, Vincent
2013-04-01
Whistler mode chorus waves play a major role in the loss and acceleration of electrons in the Earth's radiation belts. While high time resolution satellite data show that these waves are highly structured in frequency and time, at present their effects on the electron distribution can only be assessed on a global scale by using quasi-linear diffusion theory. Here we present new quasi-linear diffusion coefficients for upper and lower band chorus waves for use in global radiation belt models. Using data from DE 1 CRRES, Cluster 1, Double Star TC1 and THEMIS, we have constructed a database of wave properties and used this to construct new diffusion coefficients for L* = 1.5 to 10 in steps of 0.5, 10 latitude bins between 0o and 60o ,8 bins in MLT and 5 levels of geomagnetic activity as measured by Kp. We find that the peak frequency of lower band chorus is close to 0.2 fce, which is lower than that used in previous models. The combined upper and lower band chorus diffusion shows structure that should result in an energy dependent pitch angle anisotropy, particularly between 1 keV and 100 keV. The diffusion rates suggest that wave-particle interactions should still be very important outside geostationary orbit, out to at least L* = 8. We find significant energy diffusion near 1 keV near the loss cone, consistent with wave growth. By including the new chorus diffusion matrix into the BAS radiation belt (BRB) model we compare the effects on the evolution of the radiation belts against previous models.
Nano- and mesoscale modeling of cement matrix
NASA Astrophysics Data System (ADS)
Yu, Zechuan; Lau, Denvid
2015-04-01
Atomistic simulations of cementitious material can enrich our understanding of its structural and mechanical properties, whereas current computational capacities restrict the investigation length scale within 10 nm. In this context, coarse-grained simulations can translate the information from nanoscale to mesoscale, thus bridging the multi-scale investigations. Here, we develop a coarse-grained model of cement matrix using the concept of disk-like building block. The objective is to introduce a new method to construct a coarse-grained model of cement, which could contribute to the scale-bridging issue from nanoscale to mesoscale. PAC codes: 07.05.Tp, 62.25.-g, 82.70.Dd
Corrosion Resistance of Metal Matrix Composites.
1992-10-01
fibers was found to reduce the corrosion rate by a factor of twenty in NaC1 solutions. Al4C3 hydrolysis was not observed on the time scale of the...on the anodic polarization behavior of the G/Al MMCs with A14C3 contents measured by gas chromatography. 2.1.1 Al4C3 at the Fiber-Matrix Interface The...and Al4C3 content were not as significant in affecting the passive current density as was the type of graphite fiber used in processing the
Nano- and mesoscale modeling of cement matrix.
Yu, Zechuan; Lau, Denvid
2015-01-01
Atomistic simulations of cementitious material can enrich our understanding of its structural and mechanical properties, whereas current computational capacities restrict the investigation length scale within 10 nm. In this context, coarse-grained simulations can translate the information from nanoscale to mesoscale, thus bridging the multi-scale investigations. Here, we develop a coarse-grained model of cement matrix using the concept of disk-like building block. The objective is to introduce a new method to construct a coarse-grained model of cement, which could contribute to the scale-bridging issue from nanoscale to mesoscale. PAC codes: 07.05.Tp, 62.25.-g, 82.70.Dd.
NASA Astrophysics Data System (ADS)
Edwina, M.; Sugeng, K. A.
2017-07-01
Let G be a graph with V(G) = {v1, …, vn} and E(G) = {e1, …, .em}. We only consider undirected graphs with no multiple edges in this paper. The adjacency matrix of G, denoted by A(G), is the n × n matrix A = [aij], where aij = 1 if e = vivj ∈ E(G) or otherwise aij = 0. The anti adjacency matrix of G, denoted by B(G), is the n × n matrix B = [bij], where bij = 0 if e = vivj ∈ E(G) or otherwise bij = 1. Properties of the determinant of the adjacency matrix of some simple graphs have been studied by many researchers. However, the determinant of the anti-adjacency matrix has not been explored yet. If G1 and G2 are disjoint graphs, then the joining of two graphs G1 and G2, denoted G1 ∇ G2 is defined by taking copies of G1 and G2 and adding edges so that each vertex in G1 is adjacent to every vertex in G2. In this paper, we show the properties of the determinant of joining two graphs, G1 and G2. Union of two graphs, denote G1 ∪ G2 is a graph formed by taking copies of G1 and G2. The objectives of this paper are to identify some properties of the determinant anti adjacency matrix of joining and union operation from two disjoint graphs. This paper also emphasizes on investigating the determinant of some special graph class formed by joining and unioning operation of two disjoint of several classes of graphs, such as Bipartite graphs, Cycles, Complete graphs, Stars, and Wheels.
Properties of five toughened matrix composite materials
NASA Technical Reports Server (NTRS)
Cano, Roberto J.; Dow, Marvin B.
1992-01-01
The use of toughened matrix composite materials offers an attractive solution to the problem of poor damage tolerance associated with advanced composite materials. In this study, the unidirectional laminate strengths and moduli, notched (open-hole) and unnotched tension and compression properties of quasi-isotropic laminates, and compression-after-impact strengths of five carbon fiber/toughened matrix composites, IM7/E7T1-2, IM7/X1845, G40-800X/5255-3, IM7/5255-3, and IM7/5260 have been evaluated. The compression-after-impact (CAI) strengths were determined primarily by impacting quasi-isotropic laminates with the NASA Langley air gun. A few CAI tests were also made with a drop-weight impactor. For a given impact energy, compression after impact strengths were determined to be dependent on impactor velocity. Properties and strengths for the five materials tested are compared with NASA data on other toughened matrix materials (IM7/8551-7, IM6/1808I, IM7/F655, and T800/F3900). This investigation found that all five materials were stronger and more impact damage tolerant than more brittle carbon/epoxy composite materials currently used in aircraft structures.
NASA Astrophysics Data System (ADS)
Oehlmann, Dietmar; Ohlmann, Odile M.; Danzebrink, Hans U.
2005-04-01
perform this exchange, as a matrix, understood as source, of new ideas.
Matrix cracking in brittle-matrix composites with tailored interfaces
Danchaivijit, S.; Chao, L.Y.; Shetty, D.K.
1995-10-01
Matrix cracking from controlled through cracks with bridging filaments was studied in a model unidirectional composite of SiC filaments in an epoxy-bonded alumina matrix. An unbonded, frictional interface was produced by moderating the curing shrinkage of the epoxy with the alumina filler and coating the filaments with a releasing agent. Uniaxial tension test specimens (2.5 x 25 x 125 mm) with filament-bridged through cracks were fabricated by a novel two-step casting technique involving casting, precracking and joining of cracked and uncracked sections. Distinct matrix-cracking stresses, corresponding to the extension of the filament-bridged cracks, were measured in uniaxial tension tests using a high-sensitivity extensometer. The crack-length dependence of the matrix-cracking stress was found to be in good agreement with the prediction of a fracture-mechanics analysis that employed a new crack-closure force-crack-opening displacement relation in the calculation of the stress intensity for fiber-bridged cracks. The prediction was based on independent experimental measurements of the matrix fracture toughness (K{sub cm}), the interfacial sliding friction stress ({tau}) and the residual stress in the matrix ({sigma}{sub m}{sup I}). The matrix-cracking stress for crack lengths (2a) greater than 3 mm was independent of the crack length and agreed with the prediction of the steady-state theory of Budiansky, Hutchinson and Evans. Tests on specimens without the deliberately introduced cracks indicated a matrix-cracking stress significantly higher than the steady-state stress.
Controlled release evaluation of bacterial fertilizer using polymer composites as matrix.
Wu, Chin-San
2008-11-24
The use of polybutylene succinate (PBSU)/starch-type composite as biodegradable matrix material for the controlled release of bacterial fertilizer was evaluated. The composites were prepared by a melting-blending method and various methods/instruments were applied to characterize composites and PBSU. The mechanical properties of the PBSU/starch composite were worse than PBSU alone because the former had poor compatibility between starch and the polymer matrix. Much better dispersion and homogeneity were observed in the composite when PBSU was replaced by acrylic acid grafted PBSU (PBSU-g-AA), hence leading to better mechanical properties of PBSU-g-AA/starch. Furthermore, PBSU-g-AA/starch was more easily processed. The bacterial fertilizer was encapsulated in PBSU and PBSU-g-AA/starch matrix. Increased blending of starch increased the biodegradability of matrix and the amount and rate of cell release from matrix suggesting that this composite is a promising candidate material for 'controlled release' bacterial fertilizer.
New pole placement algorithm - Polynomial matrix approach
NASA Technical Reports Server (NTRS)
Shafai, B.; Keel, L. H.
1990-01-01
A simple and direct pole-placement algorithm is introduced for dynamical systems having a block companion matrix A. The algorithm utilizes well-established properties of matrix polynomials. Pole placement is achieved by appropriately assigning coefficient matrices of the corresponding matrix polynomial. This involves only matrix additions and multiplications without requiring matrix inversion. A numerical example is given for the purpose of illustration.
Matrix Fourth-Complex Variables
NASA Astrophysics Data System (ADS)
Dimiev, Stancho; Marinov, Marin S.; Stoev, Peter
2009-11-01
In the paper we consider quasi-cyclic hyper-complex variables which are naturally related to the partial differential equations with complex variables. In fact, we develop a matrix 4×4 generalization of the classical bicomplex numbers [1], [2]. We recall that a matrix 2×2 isomorphic type treatment of the classical bicomplex numbers was developed in [3]. Here we develop a matrix 4×4 generalization of the bicomplex numbers including some improvement of the papers [3] and [4]. Let us remark that a deep generalization of the considered ideas was sketch in [5] before us.
Mechanotransduction and extracellular matrix homeostasis
Humphrey, Jay D.; Dufresne, Eric R.; Schwartz, Martin A.
2015-01-01
Preface Soft connective tissues at steady state are yet dynamic; resident cells continually read environmental cues and respond to promote homeostasis, including maintenance of the mechanical properties of the extracellular matrix that are fundamental to cellular and tissue health. The mechanosensing process involves assessment of the mechanics of the matrix by the cells through integrins and the actomyosin cytoskeleton, and is followed by a mechano-regulation process that includes the deposition, rearrangement, or removal of matrix to maintain overall form and function. Progress toward understanding the molecular, cellular, and tissue scale effects that promote mechanical homeostasis has helped identify key questions for future research. PMID:25355505
Quadrality for supersymmetric matrix models
NASA Astrophysics Data System (ADS)
Franco, Sebastián; Lee, Sangmin; Seong, Rak-Kyeong; Vafa, Cumrun
2017-07-01
We introduce a new duality for N = 1 supersymmetric gauged matrix models. This 0 d duality is an order 4 symmetry, namely an equivalence between four different theories, hence we call it Quadrality. Our proposal is motivated by mirror symmetry, but is not restricted to theories with a D-brane realization and holds for general N = 1 matrix models. We present various checks of the proposal, including the matching of: global symmetries, anomalies, deformations and the chiral ring. We also consider quivers and the corresponding quadrality networks. Finally, we initiate the study of matrix models that arise on the worldvolume of D(-1)-branes probing toric Calabi-Yau 5-folds.
High Temperature Polymer Matrix Composites
NASA Technical Reports Server (NTRS)
1985-01-01
These are the proceedings of the High Temperature Polymer Matrix Composites Conference held at the NASA Lewis Research Center on March 16 to 18, 1983. The purpose of the conference is to provide scientists and engineers working in the field of high temperature polymer matrix composites an opportunity to review, exchange, and assess the latest developments in this rapidly expanding area of materials technology. Technical papers are presented in the following areas: (1) matrix development; (2) adhesive development; (3) characterization; (4) environmental effects; and (5) applications.
High temperature polymer matrix composites
NASA Technical Reports Server (NTRS)
Serafini, Tito T. (Editor)
1987-01-01
These are the proceedings of the High Temperature Polymer Matrix Composites Conference held at the NASA Lewis Research Center on March 16 to 18, 1983. The purpose of the conference is to provide scientists and engineers working in the field of high temperature polymer matrix composites an opportunity to review, exchange, and assess the latest developments in this rapidly expanding area of materials technology. Technical papers are presented in the following areas: (1) matrix development; (2) adhesive development; (3) Characterization; (4) environmental effects; and (5) applications.
Genotype imputation via matrix completion
Chi, Eric C.; Zhou, Hua; Chen, Gary K.; Del Vecchyo, Diego Ortega; Lange, Kenneth
2013-01-01
Most current genotype imputation methods are model-based and computationally intensive, taking days to impute one chromosome pair on 1000 people. We describe an efficient genotype imputation method based on matrix completion. Our matrix completion method is implemented in MATLAB and tested on real data from HapMap 3, simulated pedigree data, and simulated low-coverage sequencing data derived from the 1000 Genomes Project. Compared with leading imputation programs, the matrix completion algorithm embodied in our program MENDEL-IMPUTE achieves comparable imputation accuracy while reducing run times significantly. Implementation in a lower-level language such as Fortran or C is apt to further improve computational efficiency. PMID:23233546
NASA Astrophysics Data System (ADS)
Chan, Garnet Kin-Lic; Keselman, Anna; Nakatani, Naoki; Li, Zhendong; White, Steven R.
2016-07-01
Current descriptions of the ab initio density matrix renormalization group (DMRG) algorithm use two superficially different languages: an older language of the renormalization group and renormalized operators, and a more recent language of matrix product states and matrix product operators. The same algorithm can appear dramatically different when written in the two different vocabularies. In this work, we carefully describe the translation between the two languages in several contexts. First, we describe how to efficiently implement the ab initio DMRG sweep using a matrix product operator based code, and the equivalence to the original renormalized operator implementation. Next we describe how to implement the general matrix product operator/matrix product state algebra within a pure renormalized operator-based DMRG code. Finally, we discuss two improvements of the ab initio DMRG sweep algorithm motivated by matrix product operator language: Hamiltonian compression, and a sum over operators representation that allows for perfect computational parallelism. The connections and correspondences described here serve to link the future developments with the past and are important in the efficient implementation of continuing advances in ab initio DMRG and related algorithms.
Chan, Garnet Kin-Lic; Keselman, Anna; Nakatani, Naoki; Li, Zhendong; White, Steven R
2016-07-07
Current descriptions of the ab initio density matrix renormalization group (DMRG) algorithm use two superficially different languages: an older language of the renormalization group and renormalized operators, and a more recent language of matrix product states and matrix product operators. The same algorithm can appear dramatically different when written in the two different vocabularies. In this work, we carefully describe the translation between the two languages in several contexts. First, we describe how to efficiently implement the ab initio DMRG sweep using a matrix product operator based code, and the equivalence to the original renormalized operator implementation. Next we describe how to implement the general matrix product operator/matrix product state algebra within a pure renormalized operator-based DMRG code. Finally, we discuss two improvements of the ab initio DMRG sweep algorithm motivated by matrix product operator language: Hamiltonian compression, and a sum over operators representation that allows for perfect computational parallelism. The connections and correspondences described here serve to link the future developments with the past and are important in the efficient implementation of continuing advances in ab initio DMRG and related algorithms.
Performance Appraisal for Matrix Management.
ERIC Educational Resources Information Center
Edwards, M. R.; Sproull, J. Ruth
1985-01-01
A matrix management system designed for use by a highly technical nuclear weapons research and development facility to improve productivity and flexibility by the use of multiple authority, responsibility, and accountability relationships is described. (MSE)
Stochastic determination of matrix determinants.
Dorn, Sebastian; Ensslin, Torsten A
2015-07-01
Matrix determinants play an important role in data analysis, in particular when Gaussian processes are involved. Due to currently exploding data volumes, linear operations-matrices-acting on the data are often not accessible directly but are only represented indirectly in form of a computer routine. Such a routine implements the transformation a data vector undergoes under matrix multiplication. While efficient probing routines to estimate a matrix's diagonal or trace, based solely on such computationally affordable matrix-vector multiplications, are well known and frequently used in signal inference, there is no stochastic estimate for its determinant. We introduce a probing method for the logarithm of a determinant of a linear operator. Our method rests upon a reformulation of the log-determinant by an integral representation and the transformation of the involved terms into stochastic expressions. This stochastic determinant determination enables large-size applications in Bayesian inference, in particular evidence calculations, model comparison, and posterior determination.
Titanium matrix composites: Mechanical behavior
Mall, S.; Nicholas, T.
1997-12-31
Because of their unique mix of properties and behavior in high-performance applications, Titanium Matrix Composites are presently the focus of special research and development activity. This new book presents a review of current technology on the mechanical behavior of these materials. Each chapter was prepared specifically for this new book by one or more specialists in this subject. This book is divided into the following chapters: (1) Introduction; (2) Monotonic Response; (3) Micromechanical Theories for Inelastic Fibrous Composite Materials; (4) Interfaces in Metal Matrix Composites; (5) Fatigue Failure Mechanisms in TMCs; (6) Fatigue and Thermomechanical Fatigue Life Prediction; (7) Creep Behavior of Fiber Reinforced Titanium Matrix Composites; (8) Fatigue Crack Growth; (9) Notch Strength of Titanium Matrix Composites; and (10) Micromechanical Analysis and Modeling.
Performance Appraisal for Matrix Management.
ERIC Educational Resources Information Center
Edwards, M. R.; Sproull, J. Ruth
1985-01-01
A matrix management system designed for use by a highly technical nuclear weapons research and development facility to improve productivity and flexibility by the use of multiple authority, responsibility, and accountability relationships is described. (MSE)
Matrix quantum mechanics from qubits
NASA Astrophysics Data System (ADS)
Hartnoll, Sean A.; Huijse, Liza; Mazenc, Edward A.
2017-01-01
We introduce a transverse field Ising model with order N 2 spins interacting via a nonlocal quartic interaction. The model has an O( N, ℤ), hyperoctahedral, symmetry. We show that the large N partition function admits a saddle point in which the symmetry is enhanced to O( N). We further demonstrate that this `matrix saddle' correctly computes large N observables at weak and strong coupling. The matrix saddle undergoes a continuous quantum phase transition at intermediate couplings. At the transition the matrix eigenvalue distribution becomes disconnected. The critical excitations are described by large N matrix quantum mechanics. At the critical point, the low energy excitations are waves propagating in an emergent 1 + 1 dimensional spacetime.
Topological field theory and matrix product states
NASA Astrophysics Data System (ADS)
Kapustin, Anton; Turzillo, Alex; You, Minyoung
2017-08-01
It is believed that most (perhaps all) gapped phases of matter can be described at long distances by topological quantum field theory (TQFT). On the other hand, it has been rigorously established that in 1+1d ground states of gapped Hamiltonians can be approximated by matrix product states (MPS). We show that the state-sum construction of 2d TQFT naturally leads to MPS in their standard form. In the case of systems with a global symmetry G , this leads to a classification of gapped phases in 1+1d in terms of Morita-equivalence classes of G -equivariant algebras. Nonuniqueness of the MPS representation is traced to the freedom of choosing an algebra in a particular Morita class. In the case of short-range entangled phases, we recover the group cohomology classification of SPT phases.
Molybdenum disilicide alloy matrix composite
Petrovic, John J.; Honnell, Richard E.; Gibbs, W. Scott
1990-01-01
Compositions of matter consisting of matrix matrials having silicon carbide dispersed throughout them and methods of making the compositions. A matrix material is an alloy of an intermetallic compound, molybdenum disilicide, and at least one secondary component which is a refractory silicide. The silicon carbide dispersant may be in the form of VLS whiskers, VS whiskers, or submicron powder or a mixture of these forms.
Algorithmic deformation of matrix factorisations
NASA Astrophysics Data System (ADS)
Carqueville, Nils; Dowdy, Laura; Recknagel, Andreas
2012-04-01
Branes and defects in topological Landau-Ginzburg models are described by matrix factorisations. We revisit the problem of deforming them and discuss various deformation methods as well as their relations. We have implemented these algorithms and apply them to several examples. Apart from explicit results in concrete cases, this leads to a novel way to generate new matrix factorisations via nilpotent substitutions, and to criteria whether boundary obstructions can be lifted by bulk deformations.
Staggered chiral random matrix theory
Osborn, James C.
2011-02-01
We present a random matrix theory for the staggered lattice QCD Dirac operator. The staggered random matrix theory is equivalent to the zero-momentum limit of the staggered chiral Lagrangian and includes all taste breaking terms at their leading order. This is an extension of previous work which only included some of the taste breaking terms. We will also present some results for the taste breaking contributions to the partition function and the Dirac eigenvalues.
Molybdenum disilicide alloy matrix composite
Petrovic, J.J.; Honnell, R.E.; Gibbs, W.S.
1991-12-03
Compositions of matter consisting of matrix materials having silicon carbide dispersed throughout them and methods of making the compositions are disclosed. A matrix material is an alloy of an intermetallic compound, molybdenum disilicide, and at least one secondary component which is a refractory silicide. The silicon carbide dispersant may be in the form of VLS whiskers, VS whiskers, or submicron powder or a mixture of these forms. 3 figures.
Molybdenum disilicide alloy matrix composite
Petrovic, John J.; Honnell, Richard E.; Gibbs, W. Scott
1991-01-01
Compositions of matter consisting of matrix materials having silicon carbide dispersed throughout them and methods of making the compositions. A matrix material is an alloy of an intermetallic compound, molybdenum disilicide, and at least one secondary component which is a refractory silicide. The silicon carbide dispersant may be in the form of VLS whiskers, VS whiskers, or submicron powder or a mixture of these forms.
Universal Keplerian state transition matrix
NASA Technical Reports Server (NTRS)
Shepperd, S. W.
1985-01-01
A completely general method for computing the Keplerian state transition matrix in terms of Goodyear's universal variables is presented. This includes a new scheme for solving Kepler's problem which is a necessary first step to computing the transition matrix. The Kepler problem is solved in terms of a new independent variable requiring the evaluation of only one transcendental function. Furthermore, this transcendental function may be conveniently evaluated by means of a Gaussian continued fraction.
Recycling of aluminum matrix composites
Nishida, Yoshinori; Izawa, Norihisa; Kuramasu, Yukio
1999-03-01
Separation of matrix metals in composites was tried on alumina short fiber-reinforced aluminum and 6061 alloy composites and SiC whisker-reinforced 6061 alloy composite for recycling. It is possible to separate molten matrix metals from fibers in the composites using fluxes that are used for melt treatment to remove inclusions. About 50 vol pct of the matrix metals was separated from the alumina short fiber-reinforced composites. The separation ratio of the matrix from the SiC whisker-reinforced 6061 alloy composite was low and about 20 vol pct. The separation mechanism was discussed thermodynamically using interface free energies. Since the flux/fiber interface energy is smaller than the aluminum/fiber interface energy, the replacement of aluminum with fluxes in composites takes place easily. Gases released by the decomposition of fluxes act an important role in pushing out the molten matrix metal from the composite. The role was confirmed by the great amount cavity formed in the composite after the matrix metal flowed out.
Carbonate fuel cell matrix strengthening
Yuh, C.Y.; Haung, C.M.; Johnsen, R.
1995-12-31
The present baseline electrolyte matrix is a porous ceramic powder bed impregnated with alkali carbonate electrolyte. The matrix provides both ionic conduction and gas sealing. During fuel cell stack operation, the matrix experiences both mechanical and thermal stresses. Different mechanical characteristics of active and wet seal areas generate stress. Thermal stress is generated by nonuniform temperature distribution and thermal cycling. A carbonate fuel cell generally may experience planned and unplanned thermal cycles between 650 C and room temperature during its 40,000h life. During the cycling, the electrolyte matrix expands and contracts at a different rate from other cell components. Furthermore, the change in electrolyte volume associated with freezing/melting may generate additional thermal stress. Strengthening of the matrix may be beneficial for longer-term stability of the carbonate fuel cell with respect to repeated thermal cycling. Several promising strengtheners with improved chemical and mechanical stabilities were identified. Fibers provide the highest strengthening effect, followed by particulates. Matrix fabrication technique was successfully modified for uniformly incorporating the advanced strengtheners, maintaining the desired aspect ratio. Enhanced gas sealing demonstrated using the advanced matrices.
The measurement of fracture energy at fiber-matrix interfaces
Pegoretti, A.; DiBenedetto, A.T.
1996-12-31
The primary function of the fiber-matrix interface in composite materials is to transmit stress from the polymer matrix to the high strength reinforcing fibers. When a fiber filament breaks, cracks will propagate from the broken fiber end either by interfacial debonding, transverse and conical matrix cracking or combinations of the three modes. The strength of the interface has been characterized using micromechanical tests, such as the single fiber fragmentation test and a variety of single fiber pull-out tests. Results are generally analyzed in terms of an {open_quotes}interfacial shear stress{close_quotes}, {tau}, or a critical energy release rate, G{sub c}. It is the objective of this study to measure directly the strain energy release rate, G{sub c} associated with each observable fracture mode and to determine the effect of constituent physical properties and interfacial adhesion on its magnitude.
Research on Graphite Reinforced Glass Matrix Composites
NASA Technical Reports Server (NTRS)
Bacon, J. F.; Prewo, K. M.
1977-01-01
This report contains the results obtained in the first twelve months of research under NASA Langley Contract NAS1-14346 for the origination of graphite-fiber reinforced glass matrix composites. Included in the report is a summary of the research by other investigators in this area. The method selected to form the composites consisted of pulling the graphite fiber through a slurry containing powdered glass, winding up the graphite fiber and the glass it picks up on a drum, drying, cutting into segments, loading the tape segment into a graphite die, and hot pressing. During the course of the work, composites were made with a variety of graphite fibers in a C.G.W. 7740 (Pyrex) glass matrix. The graphite fibers used included Hercules HMS, Hercules HTS, Thornel 300S, and Celanese DG-102 and, of these, the Hercules HMS and Celanese DG-102 graphite fibers in C.G.W. 7740 gave the most interesting but widely different results. Hercules HMS fiber in C.G.W. 7740 glass (Pyrex) showed an average four-point flexural strength of 848 MPa or 127,300 psi. As the test temperature was raised from room temperature to 560 C in argon or vacuum, the strength was higher by 50 percent. However, in air, similar tests at 560 C gave a severe loss in strength. These composites also have good thermal cycle properties in argon or vacuum, greatly increased toughness compared to glass, and no loss in strength in a 100 cycle fatigue test. Celanese DG-102 fiber in C.G.W. 7740 glass (Pyrex) had a much lower flexural strength but did not suffer any loss in this strength when samples were heated to 560 C in air for 4 hrs.
Penicillin G Benzathine Injection
... to treat and prevent certain infections caused by bacteria. Penicillin G benzathine injection is in a class of antibiotics called penicillins. It works by killing bacteria that cause infections.Antibiotics such as penicillin G ...
Penicillin G Procaine Injection
... is used to treat certain infections caused by bacteria. Penicillin G procaine injection should not be used ... of medications called penicillins. It works by killing bacteria that cause infections.Antibiotics such as penicillin G ...
Matrix-assisted diffusion-ordered spectroscopy: choosing a matrix.
Gramosa, Nilce V; Ricardo, Nágila M S P; Adams, Ralph W; Morris, Gareth A; Nilsson, Mathias
2016-06-07
Diffusion-ordered spectroscopy (DOSY) is an important technique for separating the NMR signals of the components in a mixture, and relies on differences in diffusion coefficient. Standard DOSY experiments therefore struggle when the components of a mixture are of similar size, and hence diffuse at similar rates. Fortunately, the diffusion coefficients of solutes can be manipulated by changing the matrix in which they diffuse, using matrix components that interact differentially with them, a technique known as matrix-assisted DOSY. In the present investigation, we evaluate the performance of a number of new, previously used, and mixed matrices with an informative test mixture: the three positional isomers of dihydroxybenzene. The aim of this work is to present the matrix-assisted DOSY user with information about the potential utility of a set of matrices (and combinations of matrices), including ionic and non-ionic surfactants, complexing agents, polymers, and mixed solvents. A variety of matrices improved the diffusion resolution of the signals of the test system, with the best separation achieved by mixed micelles of sodium dodecyl sulfate and cetyl trimethylammonium bromide. The use of mixed matrices offers great potential for the analyst to tailor the matrix to a particular sample under study. © 2016 The Authors Magnetic Resonance in Chemistry Published by John Wiley & Sons, Ltd.
Fracture criteria for discontinuously reinforced metal matrix composites
NASA Technical Reports Server (NTRS)
Rack, H. J.; Goree, J. G.; Albritton, J.; Ratnarparkhi, P.
1988-01-01
The effect of sample configuration on the details of initial crack propagation in discontinuously whisker reinforced aluminum metal matrix composites was investigated. Care was taken to allow direct comparison of fracture toughness values utilizing differing sample configurations and orientations, holding all materials variables constant, e.g., extrusion ration, heat treatment, and chemistry.
Glycosylation of Dentin Matrix Protein 1 is critical for osteogenesis.
Sun, Yao; Weng, Yuteng; Zhang, Chenyang; Liu, Yi; Kang, Chen; Liu, Zhongshuang; Jing, Bo; Zhang, Qi; Wang, Zuolin
2015-12-04
Proteoglycans play important roles in regulating osteogenesis. Dentin matrix protein 1 (DMP1) is a highly expressed bone extracellular matrix protein that regulates both bone development and phosphate metabolism. After glycosylation, an N-terminal fragment of DMP1 protein was identified as a new proteoglycan (DMP1-PG) in bone matrix. In vitro investigations showed that Ser(89) is the key glycosylation site in mouse DMP1. However, the specific role of DMP1 glycosylation is still not understood. In this study, a mutant DMP1 mouse model was developed in which the glycosylation site S(89) was substituted with G(89) (S89G-DMP1). The glycosylation level of DMP1 was down-regulated in the bone matrix of S89G-DMP1 mice. Compared with wild type mice, the long bones of S89G-DMP1 mice showed developmental changes, including the speed of bone remodeling and mineralization, the morphology and activities of osteocytes, and activities of both osteoblasts and osteoclasts. These findings indicate that glycosylation of DMP1 is a key posttranslational modification process during development and that DMP1-PG functions as an indispensable proteoglycan in osteogenesis.
Glycosylation of Dentin Matrix Protein 1 is critical for osteogenesis
Sun, Yao; Weng, Yuteng; Zhang, Chenyang; Liu, Yi; Kang, Chen; Liu, Zhongshuang; Jing, Bo; Zhang, Qi; Wang, Zuolin
2015-01-01
Proteoglycans play important roles in regulating osteogenesis. Dentin matrix protein 1 (DMP1) is a highly expressed bone extracellular matrix protein that regulates both bone development and phosphate metabolism. After glycosylation, an N-terminal fragment of DMP1 protein was identified as a new proteoglycan (DMP1-PG) in bone matrix. In vitro investigations showed that Ser89 is the key glycosylation site in mouse DMP1. However, the specific role of DMP1 glycosylation is still not understood. In this study, a mutant DMP1 mouse model was developed in which the glycosylation site S89 was substituted with G89 (S89G-DMP1). The glycosylation level of DMP1 was down-regulated in the bone matrix of S89G-DMP1 mice. Compared with wild type mice, the long bones of S89G-DMP1 mice showed developmental changes, including the speed of bone remodeling and mineralization, the morphology and activities of osteocytes, and activities of both osteoblasts and osteoclasts. These findings indicate that glycosylation of DMP1 is a key posttranslational modification process during development and that DMP1-PG functions as an indispensable proteoglycan in osteogenesis. PMID:26634432
Matrix Gla Protein polymorphisms are associated with coronary artery calcification
USDA-ARS?s Scientific Manuscript database
Matrix Gla Protein (MGP) is a key regulator of vascular calcification. Genetic variation at the MGP locus could modulate the development of coronary artery calcification (CAC). We examined the cross-sectional association between MGP SNPs [rs1800802 (T-138C), rs1800801 (G-7A),and rs4236 (Ala102Thr)...
Fiber/matrix adhesion in graphite/PEKK composites
NASA Technical Reports Server (NTRS)
Bucher, R. A.; Hinkley, J. A.
1992-01-01
Experiments with poly ether ketone ketone (PEKK) resin and AS-4, IM-7, and G30-500 fibers showed excellent correlation between resin/fiber contact angle and composite transverse flexural strength as measures of resin/fiber interfacial strength. Both tests indicate the strongest interface for G30-500/PEKK followed by IM-7/PEKK and AS-4/PEKK. Also discussed are fiber effects on interlaminar fracture and on the in situ crystallization of the matrix during composite fabrication.
Fiber/matrix adhesion in graphite/PEKK composites
NASA Technical Reports Server (NTRS)
Bucher, R. A.; Hinkley, J. A.
1992-01-01
Experiments with poly ether ketone ketone (PEKK) resin and AS-4, IM-7, and G30-500 fibers showed excellent correlation between resin/fiber contact angle and composite transverse flexural strength as measures of resin/fiber interfacial strength. Both tests indicate the strongest interface for G30-500/PEKK followed by IM-7/PEKK and AS-4/PEKK. Also discussed are fiber effects on interlaminar fracture and on the in situ crystallization of the matrix during composite fabrication.
The Astrobiology Matrix and the "Drake Matrix" in Education
NASA Technical Reports Server (NTRS)
Mizser, A.; Kereszturi, A.
2003-01-01
We organized astrobiology lectures in the Eotvos Lorand University of Sciences and the Polaris Observatory in 2002. We present here the "Drake matrix" for the comparison of the astrobiological potential of different bodies [1], and astrobiology matrix for the visualization of the interdisciplinary connections between different fields of astrobiology. Conclusion: In Hungary it is difficult to integrate astrobiology in the education system but the great advantage is that it can connect different scientific fields and improve the view of students. We would like to get in contact with persons and organizations who already have experience in the education of astrobiology.
Gomes, Isabella Azevedo; Filho, Etevaldo Matos Maia; Mariz, Debora Castelo Branco Rios; Borges, Alvaro Henrique; Tonetto, Mateus Rodrigues; Firoozmand, Leily Macedo; Kuga, Carlos Milton; De Jesus, Rudys Rodolfo Tavarez; Bandéca, Matheus Coelho
2015-08-01
The aim of this in vivo study was to radiographically evaluate the proximal contour of composite resin restorations performed using different matrix systems. Patients with premolars needing class II type resin composite restorations involving the marginal ridge were selected. Thirty premolars were selected and randomly divided into three groups (n = 10 each) to receive restorations using different matrix systems: group 1: metal matrix coupled to a carrier matrix and wood wedge (G1-MMW); group 2: sectioned and precontoured metal matrix and elastic wedge (G2-SME); and group 3: a polyester strip and reflective wedge (G3-PMR). After the restorative procedure, bitewing radiographs were performed and analyzed by three calibrated professionals. The quality of the proximal contact and marginal adaptation of the proximal surfaces was classified as either correct or incorrect (undercontour/overcontour). The Pearson Chi-square statistical test (α = 5%) revealed a statistically difference between frequencies of correct and incorrect restorations (α(2) = 6.787, p < 0.05). The group G2 SME produced a higher frequency of correct proximal contours (90%), while G1-MMW and G3-PMR had a ratio of 40% correct and 60% incorrect contours respectively. None of the matrix systems was able to prevent the formation of incorrect proximal contours; however, the sectioned and precontoured metal matrix/elastic wedge configuration provided better results as compared to the other groups.
Relativistic Dipole Matrix Element Zeros
NASA Astrophysics Data System (ADS)
Lajohn, L. A.; Pratt, R. H.
2002-05-01
There is a special class of relativistic high energy dipole matrix element zeros (RZ), whose positions with respect to photon energy ω , only depend on the bound state l quantum number according to ω^0=mc^2/(l_b+1) (independent of primary quantum number n, nuclear charge Z, central potential V and dipole retardation). These RZ only occur in (n,l_b,j_b)arrow (ɛ , l_b+1,j_b) transitions such as ns_1/2arrow ɛ p_1/2; np_3/2arrow ɛ d_3/2: nd_5/2arrow ɛ f_5/2 etc. The nonrelativistic limit of these matrix elements can be established explicitly in the Coulomb case. Within the general matrix element formalism (such as that in [1]); when |κ | is substituted for γ in analytic expressions for matrix elements, the zeros remain, but ω^0 now becomes dependent on n and Z. When the reduction to nonrelativistic form is completed by application of the low energy approximation ω mc^2 mc^2, the zeros disappear. This nonzero behavior was noted in nonrelativistic dipole Coulomb matrix elements by Fano and Cooper [2] and later proven by Oh and Pratt[3]. (J. H. Scofield, Phys. Rev. A 40), 3054 (1989 (U. Fano and J. W. Cooper, Rev. Mod. Phys. 40), 441 (1968). (D. Oh and R. H. Pratt, Phys. Rev. A 34), 2486 (1986); 37, 1524 (1988); 45, 1583 (1992).
Matrix factorizations and elliptic fibrations
NASA Astrophysics Data System (ADS)
Omer, Harun
2016-09-01
I use matrix factorizations to describe branes at simple singularities of elliptic fibrations. Each node of the corresponding Dynkin diagrams of the ADE-type singularities is associated with one indecomposable matrix factorization which can be deformed into one or more factorizations of lower rank. Branes with internal fluxes arise naturally as bound states of the indecomposable factorizations. Describing branes in such a way avoids the need to resolve singularities. This paper looks at gauge group breaking from E8 fibers down to SU (5) fibers due to the relevance of such fibrations for local F-theory GUT models. A purpose of this paper is to understand how the deformations of the singularity are understood in terms of its matrix factorizations. By systematically factorizing the elliptic fiber equation, this paper discusses geometries which are relevant for building semi-realistic local models. In the process it becomes evident that breaking patterns which are identical at the level of the Kodaira type of the fibers can be inequivalent at the level of matrix factorizations. Therefore the matrix factorization picture supplements information which the conventional less detailed descriptions lack.
Association of Chromosome Territories with the Nuclear Matrix
Ma, Hong; Siegel, Alan J.; Berezney, Ronald
1999-01-01
To study the possible role of the nuclear matrix in chromosome territory organization, normal human fibroblast cells are treated in situ via classic isolation procedures for nuclear matrix in the absence of nuclease (e.g., DNase I) digestion, followed by chromosome painting. We report for the first time that chromosome territories are maintained intact on the nuclear matrix. In contrast, complete extraction of the internal nuclear matrix components with RNase treatment followed by 2 M NaCl results in the disruption of higher order chromosome territory architecture. Correlative with territorial disruption is the formation of a faint DNA halo surrounding the nuclear lamina and a dispersive effect on the characteristically discrete DNA replication sites in the nuclear interior. Identical results were obtained using eight different human chromosome paints. Based on these findings, we developed a fractionation strategy to release the bulk of nuclear matrix proteins under conditions where the chromosome territories are maintained intact. A second treatment results in disruption of the chromosome territories in conjunction with the release of a small subset of acidic proteins. These proteins are distinct from the major nuclear matrix proteins and may be involved in mediating chromosome territory organization. PMID:10444063
Extracellular matrix components mark the territories of circumventricular organs.
Pócsai, Károly; Kálmán, Mihály
2014-04-30
In the central nervous system the extracellular matrix has important roles, e.g. supporting the extracellular space, controlling the tissue hydration, binding soluble factors and influencing their diffusion. The distribution of the extracellular matrix components in the brain has been mapped but data on the circumventricular organs (CVOs) is not available yet. The CVOs lack the blood-brain barrier and have relatively large perivascular spaces. The present study investigates tenascin-R and the lecticans: aggrecan, brevican, neurocan, and versican in the median eminence, the area postrema, the vascular organ of the lamina terminalis, the subfornical organ, the pineal body and the subcommissural organ of the rat applying immunohistochemical methods, and lectin histochemistry, using Wisteria floribunda agglutinin (WFA). The extracellular matrix components were found intensely expressed in the CVOs with two exceptions: aggrecan immunoreactivity visualized only neurons in the arcuate nucleus, and the subcommissural organ was not labeled with either WFA, or lecticans, or tenascin-R. The different labelings usually overlapped each other. The distribution of the extracellular matrix components marked the territories of the CVOs. Considering these we suppose that the extracellular matrix is essential in the maintenance of CVO functions providing the large extracellular space which is required for diffusion and other processes important in their chemosensitive and neurosecretory activities. The decrease of extracellular matrix beyond the border of the organs may contribute to the control of the diffusion of molecules from the CVOs into the surrounding brain substance. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.
Methodology and utility of a job-exposure matrix
Plato, N.; Steineck, G. )
1993-01-01
We have previously reported a study in which a job-exposure matrix was applied to census data, identifying, e.g., polychlorinated biphenyls (PCBs) and creosote as increasing the risk of urothelial cancer. In this article, we expand on some theoretical issues, and present detailed accounts of constructed linkages for PCBs, creosote, and phenols. For agents of interest, one should emphasize the positive predictive value rather than the sensitivity in the construction of the matrix. The reverse is true for confounding factors; to avoid residual confounding after restriction to subjects unexposed for the confounding factors, one should emphasize sensitivity, possibly compromising the positive predictive value. This discrepancy between agents of interest and confounding factors may limit the application of a general matrix for studying several different diseases. The construction of the matrix is much harder, if sensitivity rather than positive predictive value is emphasized for an agent. Confounding from industry-related agents arises due to a true mixed exposure in certain work tasks, but also due to a gross classification of occupations in the census. One should not confuse different levels of the positive predictive value with exposure dose. A dose-response with different levels of positive predictive value reflects an accuracy of the matrix, not a biological phenomenon. Studies with exposure information from a job-exposure matrix applied to registers with scant information on occupation and industry may be warranted for exposures and diseases for which previous studies with a detailed documentation of exposure have low precision. 31 refs.
The use of matrix training to promote generative language with children with autism.
Frampton, Sarah E; Wymer, Sarah C; Hansen, Bethany; Shillingsburg, M Alice
2016-12-01
Matrix training consists of planning instruction by arranging components of desired skills across 2 axes. After training with diagonal targets that each combine 2 unique skill components, responses to nondiagonal targets, consisting of novel combinations of the components, may emerge. A multiple-probe design across participants was used to evaluate matrix training with known nouns (e.g., cat) and verbs (e.g., jumping) with 5 children with autism spectrum disorders (ASD). Following baseline of Matrix 1 and a generalization matrix, diagonal targets within Matrix 1 were trained as noun-verb combinations (e.g., cat jumping). Posttests showed recombinative generalization within Matrix 1 and the generalization matrix for 4 participants. For 1 participant, diagonal training across multiple matrices was provided until correct responding was observed in the generalization matrix. Results support the use of matrix training to promote untrained responses for learners with ASD and offer a systematic way to evaluate the extent of generalization within and across matrices. © 2016 Society for the Experimental Analysis of Behavior.
Noncommutative spaces from matrix models
NASA Astrophysics Data System (ADS)
Lu, Lei
Noncommutative (NC) spaces commonly arise as solutions to matrix model equations of motion. They are natural generalizations of the ordinary commutative spacetime. Such spaces may provide insights into physics close to the Planck scale, where quantum gravity becomes relevant. Although there has been much research in the literature, aspects of these NC spaces need further investigation. In this dissertation, we focus on properties of NC spaces in several different contexts. In particular, we study exact NC spaces which result from solutions to matrix model equations of motion. These spaces are associated with finite-dimensional Lie-algebras. More specifically, they are two-dimensional fuzzy spaces that arise from a three-dimensional Yang-Mills type matrix model, four-dimensional tensor-product fuzzy spaces from a tensorial matrix model, and Snyder algebra from a five-dimensional tensorial matrix model. In the first part of this dissertation, we study two-dimensional NC solutions to matrix equations of motion of extended IKKT-type matrix models in three-space-time dimensions. Perturbations around the NC solutions lead to NC field theories living on a two-dimensional space-time. The commutative limit of the solutions are smooth manifolds which can be associated with closed, open and static two-dimensional cosmologies. One particular solution is a Lorentzian fuzzy sphere, which leads to essentially a fuzzy sphere in the Minkowski space-time. In the commutative limit, this solution leads to an induced metric that does not have a fixed signature, and have a non-constant negative scalar curvature, along with singularities at two fixed latitudes. The singularities are absent in the matrix solution which provides a toy model for resolving the singularities of General relativity. We also discussed the two-dimensional fuzzy de Sitter space-time, which has irreducible representations of su(1,1) Lie-algebra in terms of principal, complementary and discrete series. Field
Tests for Linear Trend in the Smallest Eigenvalues of the Correlation Matrix.
ERIC Educational Resources Information Center
Bentler, Peter M.; Yuan, Ke-Hai
1998-01-01
A test for linear trend among a set of eigenvalues of a correlation matrix is described. It is a generalization of G. Anderson's (1965) test for the equality of eigenvalues and extends the present authors' previous work on linear trends in eigenvalues of a covariance matrix. The linear trend hypothesis is discussed. (SLD)
Matrix model approach to cosmology
NASA Astrophysics Data System (ADS)
Chaney, A.; Lu, Lei; Stern, A.
2016-03-01
We perform a systematic search for rotationally invariant cosmological solutions to toy matrix models. These models correspond to the bosonic sector of Lorentzian Ishibashi, Kawai, Kitazawa and Tsuchiya (IKKT)-type matrix models in dimensions d less than ten, specifically d =3 and d =5 . After taking a continuum (or commutative) limit they yield d -1 dimensional Poisson manifolds. The manifolds have a Lorentzian induced metric which can be associated with closed, open, or static space-times. For d =3 , we obtain recursion relations from which it is possible to generate rotationally invariant matrix solutions which yield open universes in the continuum limit. Specific examples of matrix solutions have also been found which are associated with closed and static two-dimensional space-times in the continuum limit. The solutions provide for a resolution of cosmological singularities, at least within the context of the toy matrix models. The commutative limit reveals other desirable features, such as a solution describing a smooth transition from an initial inflation to a noninflationary era. Many of the d =3 solutions have analogues in higher dimensions. The case of d =5 , in particular, has the potential for yielding realistic four-dimensional cosmologies in the continuum limit. We find four-dimensional de Sitter d S4 or anti-de Sitter AdS4 solutions when a totally antisymmetric term is included in the matrix action. A nontrivial Poisson structure is attached to these manifolds which represents the lowest order effect of noncommutativity. For the case of AdS4 , we find one particular limit where the lowest order noncommutativity vanishes at the boundary, but not in the interior.
Soil matrix and macropore biodegradation of 2,4-D
Pivetz, B.E.; Steenhuis, T.S.
1995-07-01
Preferential flow of pesticides in macropores can lead to decreased travel times through the vadose zone and increased groundwater contamination. Macropores, however, may present a favorable environment for biodegradation because of greater oxygen, nutrient, and substrate supply, and higher microbial populations in earthworm burrows, compared to the soil matrix. The biodegradation of 2,4-dichlorophenoxyacetic acid (2,4-D) was measured in macropores and soil matrix of packed soil columns (7.0-cm diam., 10-cm length) and undisturbed cores contained as well-defined artificial macropore and the undisturbed cores contained earthworm-burrow macropores. A 50 {mu}g/L 2,4-D solution was continuously applied to the unsaturated soil surface and breakthrough curves (BTCs) indicating pesticide loss in the effluent were obtained from the soil matrix and macropore flow paths. Biodegradation rates were calculated separately for each flow path by comparing the BTCs to BTCs representing abiotic conditions, and dividing the 2,4-D loss by the travel time through each flow path. The biodegradation rates increased with time in both flow paths, and the final biodegradation rate in the macropore region surpassed that of the matrix, presumably because of increased microbial populations in the macropore. Complete loss of the 2,4-D in both flow paths was observed after continuous application of 2,4-D for 400 h, with maximum column-averaged 2,4-D loss rates of 0.879 {mu}g/(L h) in the matrix and 1.073 {mu}g/(L h) in the macropore. Biodegradation of 2,4-D was also observed in the macropore and matrix regions of the undisturbed soil cores. 19 refs., 7 figs., 2 tabs.
Shrinkage estimation of the realized relationship matrix
USDA-ARS?s Scientific Manuscript database
The additive relationship matrix plays an important role in mixed model prediction of breeding values. For genotype matrix X (loci in columns), the product XX' is widely used as a realized relationship matrix, but the scaling of this matrix is ambiguous. Our first objective was to derive a proper ...
NASA Astrophysics Data System (ADS)
Herrera, Ramón
2017-05-01
A warm inflationary universe in the context of Galileon model or G-model is studied. Under a general formalism we study the inflationary dynamics and the cosmological perturbations considering a coupling of the form G(phi,X)=g(phi) X. As a concrete example, we consider an exponential potential together with the cases in which the dissipation and Galilean coefficients are constants. Also, we study the weak regime given by the condition R<1+3gHdot phi, and the strong regime in which 1
2000-01-01
energy [1]. Judging the visual ap- pearance of the surfaces by their isophotes we got the best results with the 340 H. Prautzsch and G. Umlauf Fig. 7...An initial control net (left), parameter lines of the resulting G2-surface (middle), top-view of the surface showing isophotes (right). functional F...construction. The initial triangular control net has an irregular vertex of valence 5. The isophotes confirm that the resulting surface is G 2. Fig. 8
Google matrix of the world network of economic activities
NASA Astrophysics Data System (ADS)
Kandiah, Vivek; Escaith, Hubert; Shepelyansky, Dima L.
2015-07-01
Using the new data from the OECD-WTO world network of economic activities we construct the Google matrix G of this directed network and perform its detailed analysis. The network contains 58 countries and 37 activity sectors for years 1995 and 2008. The construction of G, based on Markov chain transitions, treats all countries on equal democratic grounds while the contribution of activity sectors is proportional to their exchange monetary volume. The Google matrix analysis allows to obtain reliable ranking of countries and activity sectors and to determine the sensitivity of CheiRank-PageRank commercial balance of countries in respect to price variations and labor cost in various countries. We demonstrate that the developed approach takes into account multiplicity of network links with economy interactions between countries and activity sectors thus being more efficient compared to the usual export-import analysis. The spectrum and eigenstates of G are also analyzed being related to specific activity communities of countries.
Measuring Sparticles with the Matrix Element
Alwall, Johan; Freitas, Ayres; Mattelaer, Olivier; /INFN, Rome3 /Rome III U. /Louvain U.
2012-04-10
We apply the Matrix Element Method (MEM) to mass determination of squark pair production with direct decay to quarks and LSP at the LHC, showing that simultaneous mass determination of squarks and LSP is possible. We furthermore propose methods for inclusion of QCD radiation effects in the MEM. The goal of the LHC at CERN, scheduled to start this year, is to discover new physics through deviations from the Standard Model (SM) predictions. After discovery of deviations from the SM, the next step will be classification of the new physics. An important first goal in this process will be establishing a mass spectrum of the new particles. One of the most challenging scenarios is pair-production of new particles which decay to invisible massive particles, giving missing energy signals. Many methods have been proposed for mass determination in such scenarios (for a recent list of references, see e.g. [1]). In this proceeding, we report the first steps in applying the Matrix Element Method (MEM) in the context of supersymmetric scenarios giving missing energy signals. After a quick review of the MEM, we will focus on squark pair production, a process where other mass determination techniques have difficulties to simultaneously determine the LSP and squark masses. Finally, we will introduce methods to extend the range of validity of the MEM, by taking into account initial state radiation (ISR) in the method.
Decellularized musculofascial extracellular matrix for tissue engineering
Wang, Lina; Johnson, Joshua A; Chang, David W.; Zhang, Qixu
2016-01-01
Ideal scaffolds that represent native extracellular matrix (ECM) properties of musculofascial tissues have great importance in musculofascial tissue engineering. However, detailed characterization of musculofascial tissues’ ECM (particularly, of fascia) from large animals is still lacking. In this study, we developed a decellularization protocol for processing pig composite musculofascial tissues. Decellularized muscle (D-muscle) and decellularized fascia (D-fascia), which are two important components of decellularized musculofascial extracellular matrix (DMM), were comprehensively characterized. D-muscle and D-fascia retained intact three-dimensional architecture, strong mechanical properties, and bioactivity of compositions such as collagen, laminin, glycosaminoglycan, and vascular endothelial growth factor. D-muscle and D-fascia provided a compatible niche for human adipose-derived stem cell integration and proliferation. Heterotopic and orthotopic implantation of D-muscle and D-fascia in a rodent model further proved their biocompatibility and myogenic properties during the remodeling process. The differing characteristics of D-muscle from D-fascia (e.g., D-muscle’s strong pro-angiogenic and pro-myogenic properties vs. D-fascia’s strong mechanical properties) indicate different clinical application opportunities of D-muscle vs. D-fascia scaffolds. DMM comprising muscle and fascia ECM as a whole unit can thus provide not only a clinically translatable platform for musculofascial tissue repair and regeneration but also a useful standard for scaffold design in musculofascial tissue engineering. PMID:23347834
ERIC Educational Resources Information Center
Aronin, Miriam; McDuffie, Thomas E., Jr.
2009-01-01
This article presents an interview with G. Kip Bollinger. G. Kip Bollinger currently works as a consultant for Intermediate Units, school districts, professional science societies, and science text and kit producers. He performs curriculum alignment, does assessment training, coaches science teachers, trains teachers in the use of specific…
Information & Technology Literacy Standards Matrix.
ERIC Educational Resources Information Center
Potter, Calvin J.; Lohr, Neah J.; Klein, Jim; Sorensen, Richard J.
Intended to help library media specialists, technology educators, and curriculum planning teams identify where specific information and technology competencies might best fit into the assessed content areas of the curriculum, this document presents a matrix that identifies the correlation between Wisconsin's Information and Technology Literacy…
NASA Astrophysics Data System (ADS)
Kuhapatanakul, Kantaphon
2015-11-01
In this note, we study the Fibonacci and Lucas p-numbers. We introduce the Lucas p-matrix and companion matrices for the sums of the Fibonacci and Lucas p-numbers to derive some interesting identities of the Fibonacci and Lucas p-numbers.
The Enrollment Analysis Matrix Concept.
ERIC Educational Resources Information Center
Chisholm, Mark
The underlying assumptions and the structure of the enrollment analysis matrix (EAM) concept are discussed. EAM is a component of the Strategic Planning Project of the National Center for Higher Education Management Systems. EAM relates changes in the population of potential students external to the institution to the impacts that might result…
Extracellular matrix and wound healing.
Maquart, F X; Monboisse, J C
2014-04-01
Extracellular matrix has been known for a long time as an architectural support for the tissues. Many recent data, however, have shown that extracellular matrix macromolecules (collagens, elastin, glycosaminoglycans, proteoglycans and connective tissue glycoproteins) are able to regulate many important cell functions, such as proliferation, migration, protein synthesis or degradation, apoptosis, etc., making them able to play an important role in the wound repair process. Not only the intact macromolecules but some of their specific domains, that we called "Matrikines", are also able to regulate many cell activities. In this article, we will summarize main findings showing the effects of extracellular matrix macromolecules and matrikines on connective tissue and epithelial cells, particularly in skin, and their potential implication in the wound healing process. These examples show that extracellular matrix macromolecules or some of their specific domains may play a major role in wound healing. Better knowledge of these interactions may suggest new therapeutic targets in wound healing defects. Copyright © 2014 Elsevier Masson SAS. All rights reserved.
[Matrix Support: a bibliographical study].
Iglesias, Alexandra; Avellar, Luziane Zacché
2014-09-01
This article presents a bibliographical review of matrix support in mental health. A search was conducted in the Virtual Health Library and the LILACS, SciELO and Google Scholar databases using the key words: "matrix support in mental health." Fourteen articles were located with the desired characteristics, which indicates that only a restricted number of publications are in circulation. The articles were analyzed with respect to their structural and methodological aspects, which revealed the absolute predominance of the use of qualitative methods and health professionals as the target research population. The same articles were then analyzed for their theoretical discussions. Among other issues, the importance of matrix support to enhance the primary health care teams provided to people suffering from psychic distress is highlighted. However, there is still considerable confusion regarding the proposal of the matrix support and shared responsibilities between teams of reference and mental health professionals, which emphasizes the need for training of these professionals, as well as better coordination and organization of the mental health care network.
Matrix Algorithms in Signal Processing
1990-08-01
low rank perturbations with applications, SIAM J. MATRIX ANAL. APPL. 9, 40-58 (1988). [2] (with P . Arbenz and W. Gander), Restricted rank...key idea is to approximate the secular equation by an integral and then bound the integral using the ideas of Gauss- Radau integration. The Lanczos
Matrix Treatment of Ray Optics.
ERIC Educational Resources Information Center
Quon, W. Steve
1996-01-01
Describes a method to combine two learning experiences--optical physics and matrix mathematics--in a straightforward laboratory experiment that allows engineering/physics students to integrate a variety of learning insights and technical skills, including using lasers, studying refraction through thin lenses, applying concepts of matrix…
Matrix Treatment of Ray Optics.
ERIC Educational Resources Information Center
Quon, W. Steve
1996-01-01
Describes a method to combine two learning experiences--optical physics and matrix mathematics--in a straightforward laboratory experiment that allows engineering/physics students to integrate a variety of learning insights and technical skills, including using lasers, studying refraction through thin lenses, applying concepts of matrix…
Integrability and generalized monodromy matrix
Lhallabi, T.; Moujib, A.
2007-09-15
We construct the generalized monodromy matrix M-circumflex({omega}) of two-dimensional string effective action by introducing the T-duality group properties. The integrability conditions with general solutions depending on spectral parameter are given. This construction is investigated for the exactly solvable Wess, Zumino, Novikov, and Witten model in pp-wave limit when B=0.
Metal Matrix Composites Directionally Solidified
NASA Astrophysics Data System (ADS)
Ares, Alicia Esther; Schvezov, Carlos Enrique
The present work is focus on studying the dendritic solidification of metal matrix composites, MMCs, (using zinc-aluminum, ZA, alloys as matrix and the addition of SiC and Al2O3 particles). The compounds were obtained by as-cast solidification, under continuous stirring and in a second stage were directionally solidified in order to obtain different dendritic growth (columnar, equiaxed and columnar-to-equiaxed transition (CET)). The results in MMCs were compared with those obtained in directional solidification of ZA alloys, primarily with regard to structural parameters. The size and evolution of microstructure, according to the size of the MMCs particles and the variation of the thermal parameters was analyzing. In general it was found that the size of the microstructure (secondary dendritic spacing) decreases with the increase of particles in the matrix. When cooling rate increases, particle size decreases, and a higher cooling rate causes finer and more homogeneous dendrites Also, the segregation which was found in the matrix of the composites was significantly less than in the case of ZA alloys.
Electrocomposite of Alumina in Nickel Matrix
NASA Technical Reports Server (NTRS)
Xiong-Skiba, Pei; Hulguin, Ryan; Engelhaupt, Darell; Ramsey, Brian
2004-01-01
Nickel/aluminum oxide composite was electroformed in a sulfamate bath with 50 g/L of 0.05-micron aluminum oxide powder. Different plating methods including direct current plating, periodic pulse plating, and periodic reverse pulse plating were used. With conventional direct current plating, the maximum particle inclusion in the nickel matrix remains about 2% (wt). However, much higher percentile particle inclusions were achieved when a specific pulse reversal plating technique was applied. The particle incorporation approaches theoretical maximum when the deposit thickness per cycle approaches the particle diameter size at lower duty cycle. The highest particle incorporation achieved is 23% (by weight). Conceptual models interpreting the dramatic differences in the results of these plating methods were also proposed.
Origin of Chondrules and Matrix in Carbonaceous Chondrites
NASA Astrophysics Data System (ADS)
Palme, H.; Spettel, B.; Ikeda, Y.
1993-07-01
We have recently shown that in Allende, chondrules and matrix are complementary in composition. Chondrules have low Fe/Cr ratios and matrix has high Fe/Cr ratios; the bulk meteorite has the CI ratio. Chondrules on the average have Ca/Al ratios below the solar system ratio of 1.10, which is also the bulk Allende ratio; matrix and related dark inclusions have ratios above 1.10. It was therefore concluded that chondrules and matrix formed from a single reservoir characteristic of the bulk Allende composition [1,2]. Recent reports on the CV meteorite Y-86751 [3,4] indicated the opposite relationship, with high Ca/Al ratios in chondrules and low ratios in matrix. Different compositions of individual components of Y-86751 and of Allende but similar bulk compositions of both meteorites may reveal important details on the preaccretionary evolution of the carbonaceous chondrites. We have therefore begun chemical analyses of the bulk of Y-86751 and its individual lithic components, chondrules, matrix, amoeboid olivine inclusions, Ca,Al-rich inclusions, etc. Results of the bulk analysis of Y-86751 show that this meteorite has (within the accuracy of the analysis) the same bulk composition as Allende. In particular, the Ca/Al ratio is within 3% of the average solar system ratio of 1.1 (by weight). The only statistically resolvable difference is the 50% higher content of Zn in Y-86751. Major-element INA analyses indicate a Ca/Al ratio above the chondritic ratio for several chondrules and opposite to that of average Allende chondrules [1]. Matrix samples have a tendency for low Ca/Al ratios, confirming EMP-matrix analyses [4]. The separates are presently analyzed for a large number of trace elements. After the analyses, separates will be investigated petrographically. The apparent disequilibrium among Allende components and the strong compositional zoning of olivine grains constrain the thermal history of the Allende parent body [e.g., 5]. Any metamorphic redistribution of Ca or
Maizels, Nancy; Gray, Lucas T.
2013-01-01
Recent experiments provide fascinating examples of how G4 DNA and G4 RNA structures—aka quadruplexes—may contribute to normal biology and to genomic pathologies. Quadruplexes are transient and therefore difficult to identify directly in living cells, which initially caused skepticism regarding not only their biological relevance but even their existence. There is now compelling evidence for functions of some G4 motifs and the corresponding quadruplexes in essential processes, including initiation of DNA replication, telomere maintenance, regulated recombination in immune evasion and the immune response, control of gene expression, and genetic and epigenetic instability. Recognition and resolution of quadruplex structures is therefore an essential component of genome biology. We propose that G4 motifs and structures that participate in key processes compose the G4 genome, analogous to the transcriptome, proteome, or metabolome. This is a new view of the genome, which sees DNA as not only a simple alphabet but also a more complex geography. The challenge for the future is to systematically identify the G4 motifs that form quadruplexes in living cells and the features that confer on specific G4 motifs the ability to function as structural elements. PMID:23637633
Mitochondrial matrix P53 sensitizes cells to oxidative stress☆
Koczor, Christopher A.; Torres, Rebecca A.; Fields, Earl J.; Boyd, Amy; Lewis, William
2013-01-01
A mitochondrial matrix-specific p53 construct (termed p53–290) in HepG2 cells was utilized to determine the impact of p53 in the mitochondrial matrix following oxidative stress. H2O2 exposure reduced cellular proliferation similarly in both p53–290 and vector cells, and p53–290 cells demonstrating decreased cell viability at 1 mM H2O2 (~85% viable). Mitochondrial DNA (mtDNA) abundance was decreased in a dose-dependent manner in p53–290 cells while no change was observed in vector cells. Oximetric analysis revealed reduced maximal respiration and reserve capacity in p53–290 cells. Our results demonstrate that mitochondrial matrix p53 sensitizes cells to oxidative stress by reducing mtDNA abundance and mitochondrial function. PMID:23499753
The Spin Structure Function g2
Rock, Stephen E.
2003-02-27
We have measured the spin structure functions g{sub 2}{sup p} and g{sub 2}{sup d} over the kinematic range 0.02 {le} x {le} 0.8 and 0.7 {le} Q{sup 2} {le} 20 GeV{sup 2} by scattering 29.1 and 32.3 GeV longitudinally polarized electrons from transversely polarized NH{sub 3} and {sup 6}LiD targets. Our measured g{sub 2} approximately follows the twist-2 Wandzura-Wilczek calculation. The twist-3 reduced matrix elements d{sub 2}{sup p} and d{sub 2}{sup n} are less than two standard deviations from zero. The data are inconsistent with the Burkhardt-Cottingham sum rule. The Efremov-Leader-Teryaev integral is consistent with zero within our measured kinematic range.
Hypergravity Stimulates Osteoblast Proliferation Via Matrix-Integrin-Signaling Pathways
NASA Technical Reports Server (NTRS)
Vercoutere, W.; Parra, M.; Roden, C.; DaCosta, M.; Wing, A.; Damsky, C.; Holton, E.; Searby, N.; Globus, R.; Almeida, E.
2003-01-01
Extensive characterizations of the physiologic consequences of microgravity and gravity indicate that lack of weight-bearing may cause tissue atrophy through cellular and subcellular level mechanisms. We hypothesize that gravity is needed for the efficient transduction of cell growth and survival signals from the extra-cellular matrix (ECM) in mechanosensitive tissues. Recent work from our laboratory and from others shows that an increase of gravity increases bone cell growth and survival. We found that 50-g hypergravity stimulation increased osteoblast proliferation for cells grown on Collagen Type I and Fibronectin, but not on Laminin or uncoated plastic. This may be a tissue-specific response, because 50-g hypergravity stimulation caused no increase in proliferation for primary rat fibroblasts. These results combined with RT-PCR for all possible integrins indicate that beta1 integrin subunit may be involved. The osteoblast proliferation response on Collagen Type I was greater at 25-g than at 10-g or 50-g; 24-h duration of hypergravity was necessary to see an increase in proliferation. Survival was enhanced during hypergravity stimulation by the presence of matrix. Flow cytometry analysis indicated that cell cycle may be altered; BrdU incorporation in proliferating cells showed an increase in the number of actively dividing cells from about 60% at 1-g to over 90% at 25-g. To further investigate the molecular components involved, we applied fluorescence labeling of cytoskeletal and signaling molecules to cells after 2 to 30 minutes of hypergravity stimulation. While structural components did not appear to be altered, phosphorylation increased, indicating that signaling pathways may be activated. These data indicate that gravity mechanostimulation of osteoblast proliferation involves specific matrix-integrin signaling pathways which are sensitive to duration and g-level.
Hypergravity Stimulates Osteoblast Proliferation Via Matrix-Integrin-Signaling Pathways
NASA Technical Reports Server (NTRS)
Vercoutere, W.; Parra, M.; Roden, C.; DaCosta, M.; Wing, A.; Damsky, C.; Holton, E.; Searby, N.; Globus, R.; Almeida, E.
2003-01-01
Extensive characterizations of the physiologic consequences of microgravity and gravity indicate that lack of weight-bearing may cause tissue atrophy through cellular and subcellular level mechanisms. We hypothesize that gravity is needed for the efficient transduction of cell growth and survival signals from the extra-cellular matrix (ECM) in mechanosensitive tissues. Recent work from our laboratory and from others shows that an increase of gravity increases bone cell growth and survival. We found that 50-g hypergravity stimulation increased osteoblast proliferation for cells grown on Collagen Type I and Fibronectin, but not on Laminin or uncoated plastic. This may be a tissue-specific response, because 50-g hypergravity stimulation caused no increase in proliferation for primary rat fibroblasts. These results combined with RT-PCR for all possible integrins indicate that beta1 integrin subunit may be involved. The osteoblast proliferation response on Collagen Type I was greater at 25-g than at 10-g or 50-g; 24-h duration of hypergravity was necessary to see an increase in proliferation. Survival was enhanced during hypergravity stimulation by the presence of matrix. Flow cytometry analysis indicated that cell cycle may be altered; BrdU incorporation in proliferating cells showed an increase in the number of actively dividing cells from about 60% at 1-g to over 90% at 25-g. To further investigate the molecular components involved, we applied fluorescence labeling of cytoskeletal and signaling molecules to cells after 2 to 30 minutes of hypergravity stimulation. While structural components did not appear to be altered, phosphorylation increased, indicating that signaling pathways may be activated. These data indicate that gravity mechanostimulation of osteoblast proliferation involves specific matrix-integrin signaling pathways which are sensitive to duration and g-level.
NASA Astrophysics Data System (ADS)
Pozharskii, A. F.; Kachalkina, S. G.; Gulevskaya, A. V.; Filatova, E. A.
2017-07-01
The data on the synthesis and properties of benzo[g]indoles accumulated mainly over a period of the past 15-20 years are integrated. Various variants of pyrrole ring and naphthalene nucleus closure are considered. It is demonstrated that, in addition to the expected similarity between benzo[g]indoles and indoles, there are noticeable differences between them as well, especially where the synthesis of the benzoindole system is concerned. Practical applications of benzo[g]indoles are discussed. The bibliography includes 199 references.
Ju, Xingzhu; Liang, Shanhui; Zhu, Jun; Ke, Guihao; Wen, Hao; Wu, Xiaohua
2016-01-01
Our preliminary study found that CD147 is related to radioresistance and maybe an adverse prognostic factor in cervical cancer. To date, the mechanisms underlying CD147-induced radioresistance in cervical cancer remain unclear. In the present study, we investigated the mechanisms by which CD147 affects radiosensitivity in cervical cancer both in vitro and in vivo. In this study, the clonogenic assay showed that radiosensitivity was significantly higher in the experimental group (the CD147-negative cell lines) than in the control group (the CD147-positive cell lines). After radiotherapy, the residual tumour volume was significantly lower in the experimental group. FCM analysis showed the cells percentage in the G2/M phase of the cell cycle were significantly higher in the CD147-negative group than in the control group. However, there was no significant difference in terms of apoptosis. The expression of gamma-H2A histone family, member X (γH2AX) was dramatically elevated in the CD147-negative cell lines after irradiation, but the expression of ataxia-telangiectasia mutated (ATM) was not different between the two groups. WB analysis did not show any other proteins relating to the expression of CD147. In conclusion, it is likely that CD147 regulates radioresistance by regulating the percentage of the cells in the G2/M phase of the cell cycle and the repair of DNA double-strand breaks (DSBs). Inhibition of CD147 expression enhances the radiosensitivity of cervical cancer cell lines and promotes post-radiotherapy xenograft tumour regression in nude mice. Therefore, CD147 may be used in individualized therapy against cervical cancer and is worth further exploration.
The G3 initiative was designed to build a collaborative network for small to mid-sized towns and communities that are interested in adopting Green Streets to address urban stormwater, improve community health and livability, and encourage economic growth.
2007-01-18
G60-02556 (8 Nov. 1960) --- Little Joe-5 prelaunch fittings shot before flight from Wallops Island. The suborbital test flight was to qualify the capsule system. The capsule did not separate from the booster. Photo credit: NASA
2007-01-18
G60-02552 (8 Nov. 1960) --- Little Joe-5 prelaunch fittings shot before flight from Wallops Island. The suborbital test flight was to qualify the capsule system. The capsule did not separate from the booster. Photo credit: NASA
2011-05-24
G4beamline is a single-particle-tracking simulation code based on the Geant4 toolkit. It is specifically optimized for the realistic evaluation of beam lines. It is especially useful for evaluating future muon facilities.
2009-06-25
41G-102-003 (5-13 Oct 1984) ---- Astronaut Kathryn D. Sullivan, 41-G mission specialist, floats into a middeck scene to join a more stationary pair of crewmembers---Astronauts Robert L. Crippen, crew commander; and Jon A. McBride, pilot. The protruding article near the stowage lockers is a Krimsky rule, part of the near vision acuity experiment in which recent NASA space travelers have participated.
q-Virasoro constraints in matrix models
NASA Astrophysics Data System (ADS)
Nedelin, Anton; Zabzine, Maxim
2017-03-01
The Virasoro constraints play the important role in the study of matrix models and in understanding of the relation between matrix models and CFTs. Recently the localization calculations in supersymmetric gauge theories produced new families of matrix models and we have very limited knowledge about these matrix models. We concentrate on elliptic generalization of hermitian matrix model which corresponds to calculation of partition function on S 3 × S 1 for vector multiplet. We derive the q-Virasoro constraints for this matrix model. We also observe some interesting algebraic properties of the q-Virasoro algebra.
Structure of collagen-glycosaminoglycan matrix and the influence to its integrity and stability.
Bi, Yuying; Patra, Prabir; Faezipour, Miad
2014-01-01
Glycosaminoglycan (GAG) is a chain-like disaccharide that is linked to polypeptide core to connect two collagen fibrils/fibers and provide the intermolecular force in Collagen-GAG matrix (C-G matrix). Thus, the distribution of GAG in C-G matrix contributes to the integrity and mechanical properties of the matrix and related tissue. This paper analyzes the transverse isotropic distribution of GAG in C-G matrix. The angle of GAGs related to collagen fibrils is used as parameters to qualify the GAGs isotropic characteristic in both 3D and 2D rendering. Statistical results included that over one third of GAGs were perpendicular directed to collagen fibril with symmetrical distribution for both 3D matrix and 2D plane cross through collagen fibrils. The three factors tested in this paper: collagen radius, collagen distribution, and GAGs density, were not statistically significant for the strength of Collagen-GAG matrix in 3D rendering. However in 2D rendering, a significant factor found was the radius of collagen in matrix for the GAGs directed to orthogonal plane of Collagen-GAG matrix. Between two cross-section selected from Collagen-GAG matrix model, the plane cross through collagen fibrils was symmetrically distributed but the total percentage of perpendicular directed GAG was deducted by decreasing collagen radius. There were some symmetry features of GAGs angle distribution in selected 2D plane that passed through space between collagen fibrils, but most models showed multiple peaks in GAGs angle distribution. With less GAGs directed to perpendicular of collagen fibril, strength in collagen cross-section weakened. Collagen distribution was also a factor that influences GAGs angle distribution in 2D rendering. True hexagonal collagen packaging is reported in this paper to have less strength at collagen cross-section compared to quasi-hexagonal collagen arrangement. In this work focus is on GAGs matrix within the collagen and its relevance to anisotropy.
High temperature polymer matrix composites
NASA Technical Reports Server (NTRS)
Meador, Michael A.
1987-01-01
With the increased emphasis on high performance aircraft the need for lightweight, thermal/oxidatively stable materials is growing. Because of their ease of fabrication, high specific strength, and ability to be tailored chemically to produce a variety of mechanical and physical properties, polymers and polymer matrix composites present themselves as attractive materials for a number of aeropropulsion applications. In the early 1970s researchers at the NASA Lewis Research Center developed a highly processable, thermally stable (600 F) polyimide, PMR-15. Since that time, PMR-15 has become commercially available and has found use in military aircraft, in particular, the F-404 engine for the Navy's F/A-18 strike fighter. The NASA Lewis'contributions to high temperature polymer matrix composite research will be discussed as well as current and future directions.
Matrix remodeling during endochondral ossification.
Ortega, Nathalie; Behonick, Danielle J; Werb, Zena
2004-02-01
Endochondral ossification, the process by which most of the skeleton is formed, is a powerful system for studying various aspects of the biological response to degraded extracellular matrix (ECM). In addition, the dependence of endochondral ossification upon neovascularization and continuous ECM remodeling provides a good model for studying the role of the matrix metalloproteases (MMPs) not only as simple effectors of ECM degradation but also as regulators of active signal-inducers for the initiation of endochondral ossification. The daunting task of elucidating their specific role during endochondral ossification has been facilitated by the development of mice deficient for various members of this family. Here, we discuss the ECM and its remodeling as one level of molecular regulation for the process of endochondral ossification, with special attention to the MMPs.
Scrambling with matrix black holes
NASA Astrophysics Data System (ADS)
Brady, Lucas; Sahakian, Vatche
2013-08-01
If black holes are not to be dreaded sinks of information but rather fully described by unitary evolution, they must scramble in-falling data and eventually leak it through Hawking radiation. Sekino and Susskind have conjectured that black holes are fast scramblers; they generate entanglement at a remarkably efficient rate, with the characteristic time scaling logarithmically with the entropy. In this work, we focus on Matrix theory—M-theory in the light-cone frame—and directly probe the conjecture. We develop a concrete test bed for quantum gravity using the fermionic variables of Matrix theory and show that the problem becomes that of chains of qubits with an intricate network of interactions. We demonstrate that the black hole system evolves much like a Brownian quantum circuit, with strong indications that it is indeed a fast scrambler. We also analyze the Berenstein-Maldacena-Nastase model and reach the same tentative conclusion.
Octonions in random matrix theory
NASA Astrophysics Data System (ADS)
Forrester, Peter J.
2017-04-01
The octonions are one of the four normed division algebras, together with the real, complex and quaternion number systems. The latter three hold a primary place in random matrix theory, where in applications to quantum physics they are determined as the entries of ensembles of Hermitian random matrices by symmetry considerations. Only for N=2 is there an existing analytic theory of Hermitian random matrices with octonion entries. We use a Jordan algebra viewpoint to provide an analytic theory for N=3. We then proceed to consider the matrix structure X†X, when X has random octonion entries. Analytic results are obtained from N=2, but are observed to break down in the 3×3 case.
Sapphire reinforced alumina matrix composites
NASA Technical Reports Server (NTRS)
Jaskowiak, Martha H.; Setlock, John A.
1994-01-01
Unidirectionally reinforced A1203 matrix composites have been fabricated by hot pressing. Approximately 30 volume % of either coated or uncoated sapphire fiber was used as reinforcement. Unstabilized ZrO2 was applied as the fiber coating. Composite mechanical behavior was analyzed both after fabrication and after additional heat treatment. The results of composite tensile tests were correlated with fiber-matrix interfacial shear strengths determined from fiber push-out tests. Substantially higher strength and greater fiber pull-out were observed for the coated fiber composites for all processing conditions studied. The coated fiber composites retained up to 95% and 87% of their as-fabricated strength when heat treated at 14000C for 8 or 24 hours, respectively. Electron microscopy analysis of the fracture surfaces revealed extensive fiber pull-out both before and after heat treatment.
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.
Corrosion of Titanium Matrix Composites
Covino, B.S., Jr.; Alman, D.E.
2002-09-22
The corrosion behavior of unalloyed Ti and titanium matrix composites containing up to 20 vol% of TiC or TiB{sub 2} was determined in deaerated 2 wt% HCl at 50, 70, and 90 degrees C. Corrosion rates were calculated from corrosion currents determined by extrapolation of the tafel slopes. All curves exhibited active-passive behavior but no transpassive region. Corrosion rates for Ti + TiC composites were similar to those for unalloyed Ti except at 90 degrees C where the composites were slightly higher. Corrosion rates for Ti + TiB{sub 2} composites were generally higher than those for unalloyed Ti and increased with higher concentrations of TiB{sub 2}. XRD and SEM-EDS analyses showed that the TiC reinforcement did not react with the Ti matrix during fabrication while the TiB{sub 2} reacted to form a TiB phase.
M* G€* GÈ****/ .25 ýÿg*ûÿg»ûÿg¹÷ÿg-ûÿg8*fh f* f»
2015-09-01
... f$*fb*fÃ*fûýÿgÞóÿg$íÿg)ìÿgNïÿg)õÿg†øÿg*öÿg¬õÿg,óÿg*óÿg›öÿgúóÿg: æÿgpÛÿgjÒÿgzÈÿg*ÅÿgFÎÿg˜âÿgîýÿgÕ*f#'f 2f–3f**fc*f*ìÿgìÖÿg¯Âÿg ... f#. ...
Tough high performance composite matrix
NASA Technical Reports Server (NTRS)
Pater, Ruth H. (Inventor); Johnston, Norman J. (Inventor)
1994-01-01
This invention is a semi-interpentrating polymer network which includes a high performance thermosetting polyimide having a nadic end group acting as a crosslinking site and a high performance linear thermoplastic polyimide. Provided is an improved high temperature matrix resin which is capable of performing in the 200 to 300 C range. This resin has significantly improved toughness and microcracking resistance, excellent processability, mechanical performance, and moisture and solvent resistances.
Myocardial structure and matrix metalloproteinases.
Aggeli, C; Pietri, P; Felekos, I; Rautopoulos, L; Toutouzas, K; Tsiamis, E; Stefanadis, C
2012-01-01
Metalloproteinases (MMPs) are enzymes which enhance proteolysis of extracellular matrix proteins. The pathophysiologic and prognostic role of MMPs has been demonstrated in numerous studies. The present review covers a wide a range of topics with regards to MMPs structural and functional properties, as well as their role in myocardial remodeling in several cardiovascular diseases. Moreover, the clinical and therapeutic implications from their assessment are highlighted.
Integrable matrix theory: Level statistics.
Scaramazza, Jasen A; Shastry, B Sriram; Yuzbashyan, Emil A
2016-09-01
We study level statistics in ensembles of integrable N×N matrices linear in a real parameter x. The matrix H(x) is considered integrable if it has a prescribed number n>1 of linearly independent commuting partners H^{i}(x) (integrals of motion) [H(x),H^{i}(x)]=0, [H^{i}(x),H^{j}(x)]=0, for all x. In a recent work [Phys. Rev. E 93, 052114 (2016)2470-004510.1103/PhysRevE.93.052114], we developed a basis-independent construction of H(x) for any n from which we derived the probability density function, thereby determining how to choose a typical integrable matrix from the ensemble. Here, we find that typical integrable matrices have Poisson statistics in the N→∞ limit provided n scales at least as logN; otherwise, they exhibit level repulsion. Exceptions to the Poisson case occur at isolated coupling values x=x_{0} or when correlations are introduced between typically independent matrix parameters. However, level statistics cross over to Poisson at O(N^{-0.5}) deviations from these exceptions, indicating that non-Poissonian statistics characterize only subsets of measure zero in the parameter space. Furthermore, we present strong numerical evidence that ensembles of integrable matrices are stationary and ergodic with respect to nearest-neighbor level statistics.
NASA Technical Reports Server (NTRS)
1995-01-01
This mosaic of WFPC-2 images shows the evolution of the Shoemaker-Levy 9 G impact site on Jupiter. The images from lower left to upper right show: the impact plume at 07/18/94 07:38 UT (about 5 minutes after the impact); the fresh impact site at 07/18/94 at 09:19 UT (1.5 hours after impact); the impact site after evolution by the winds of Jupiter (left), along with the L impact (right), taken on 07/21/94 at 6:22 UT (3 days after the G impact and 1.3 days after the L impact); and further evolution of the G and L sites due to winds and an additional impact (S) in the G vicinity, taken on 07/23/94 at 08:08 UT (5 days after the G impact).
This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/pubinfo/
Fast polar decomposition of an arbitrary matrix
NASA Technical Reports Server (NTRS)
Higham, Nicholas J.; Schreiber, Robert S.
1988-01-01
The polar decomposition of an m x n matrix A of full rank, where m is greater than or equal to n, can be computed using a quadratically convergent algorithm. The algorithm is based on a Newton iteration involving a matrix inverse. With the use of a preliminary complete orthogonal decomposition the algorithm can be extended to arbitrary A. How to use the algorithm to compute the positive semi-definite square root of a Hermitian positive semi-definite matrix is described. A hybrid algorithm which adaptively switches from the matrix inversion based iteration to a matrix multiplication based iteration due to Kovarik, and to Bjorck and Bowie is formulated. The decision when to switch is made using a condition estimator. This matrix multiplication rich algorithm is shown to be more efficient on machines for which matrix multiplication can be executed 1.5 times faster than matrix inversion.
Smallwood, D.O.
1995-08-07
It is shown that the usual method for computing the coherence functions (ordinary, partial, and multiple) for a general multiple-input/multiple-output problem can be expressed as a modified form of Cholesky decomposition of the cross spectral density matrix of the inputs and outputs. The modified form of Cholesky decomposition used is G{sub zz} = LCL{prime}, where G is the cross spectral density matrix of inputs and outputs, L is a lower; triangular matrix with ones on the diagonal, and C is a diagonal matrix, and the symbol {prime} denotes the conjugate transpose. If a diagonal element of C is zero, the off diagonal elements in the corresponding column of L are set to zero. It is shown that the results can be equivalently obtained using singular value decomposition (SVD) of G{sub zz}. The formulation as a SVD problem suggests a way to order the inputs when a natural physical order of the inputs is absent.
The Software Maturity Matrix: A Software Performance Metric
2003-01-28
S e r v i c e - E x c e l l e n c e Overview n Introduction n Software Metrics n Software Maturity Matrix ( SwMM ) n SwMM Relationship to CMM...Development Team As of: 12I n t e g r i t y - S e r v i c e - E x c e l l e n c e Software Maturity Matrix ( SwMM ) n Purpose n Description n Evolution n...Implementation As of: 13I n t e g r i t y - S e r v i c e - E x c e l l e n c e SwMM Purpose n Forces Developer Requirements Capture (User
Preparation of mesoporous zirconia microspheres as inert matrix
NASA Astrophysics Data System (ADS)
Guo, Ting; Wang, Chen; Lv, Jinlong; Liang, Tongxiang
2016-12-01
Mesoporous zirconia microspheres, with a diameter of 900 μm, were prepared as an inert accelerator driven system (ADS) transmutation element matrix by the sol-gel method. The purpose of mesopores is to improve the adsorption capacity of inert matrix fuel (IMF) for minor actinides. The study indicated that the mesoporous zirconia performance was improved after the microspheres were hydrothermally treated at 150 °C, the specific surface area increased from 28.29 m2/g to 61.28 m2/g, and hydrothermal treatment avoided the cracking of the microspheres. Pre-decomposition of the organics during the hydrothermal process stabilized the mesoporous structure. The average pore diameter of mesoporous microsphere was 14.3 nm.
Centrifugal casting of metal matrix composites. Ph.D. Thesis
Berger, R.E.
1994-01-01
Metal matrix composites (MMCs) have excellent properties and low material costs, but high manufacturing costs. The primary difficulty in manufacturing MMCs is in forming a tight matrix/reinforcement bond. This dissertation investigates improving the matrix/reinforcement bond through the use of high centrifugal forces. High centrifugal forces promote fiber infiltration (or particle submergence), remove gas voids, and resist particle pushing by the solidification front. Several aluminum matrix MMC samples are formed at up to 2,660 g`s. The project involves: (1) design and construction of a rotating crucible capable of a 690 C, 2,600 g-force environment; (2) a finite differences heat transfer model using an unique technique (spreadsheet iteration) which has application to engineering teaching and simple modeling problems; (3) a bubble buoyancy/surface adhesion analysis to predict maximum surface voids or bubble cling in cast materials; (4) a fluid surface tension effects analysis evaluating particle submergence into a melt, and melt infiltration into a porous media such as a fiber form; (5) creation of samples and direct visual measurement of void sizes in agreement with bubble buoyancy/surface adhesion theory; (6) performance of tests and direct evidence supporting the developed particle submergence/porous media infiltration theories; and (7) creation of samples and direct measurement of material strength under subjection to bending stress. The final conclusion is that use of high centrifugal forces in MMC manufacturing has potential, however it is only useful for large diameter fibers or particles (on the order of 200 micron) and relatively high g-forces (on the order of 2,500 g`s).
Calculating weak matrix elements using HYP staggered fermions
T. Bhattacharya; G. T. Fleming; G. Kilcup; R. Gupta; W. Lee; S. Sharpe
2004-03-01
We present preliminary results of weak matrix elements relevant to CP violation calculated using the HYP (II) staggered fermions. Since the complete set of matching coefficients at the one-loop level became available recently, we have constructed lattice operators with all the g{sup 2} corrections included. The main results include both {Delta}I = 3/2 and {Delta}I = 1/2 contributions.
Anisotropic Damage Mechanics Modeling in Metal Matrix Composites
1993-05-15
conducted on a titanium aluminide SiC-reinforced metal matrix composite. Center-cracked plates with laminate layups of (0/90) and (±45). were tested...Kattan, P. I., "Finite Strain Plasticity and Damage in Constitutive Modeling of Metals with Spin Tensors," Applied Mechanics Reviews, Vol. 45, No. 3...34Contractors Meeting on Mechanics of Materials," Dayton, Ohio, October 1991. Voyiadjis, G. Z., and Kattan, P. I., "Finite Strain Plasticity and Damage in
Magnesium Matrix Composite Foams-Density, Mechanical Properties, and Applications
2012-07-24
known that the effect of particle-matrix interfacial bonding is much less significant under compression compared to under tension [33,34]. One of the...parameter). Some syntactic foam composites are found to have less than 0.4 g/cc density in Figure 9. These data points belong to foams that contain...syntactic foams containing porosity only inside hollow particles. The yield strength values for various types of MMSFs, including aluminum, titanium , and
Metal-matrix composites: Status and prospects
NASA Technical Reports Server (NTRS)
1974-01-01
Applications of metal matrix composites for air frames and jet engine components are discussed. The current state of the art in primary and secondary fabrication is presented. The present and projected costs were analyzed to determine the cost effectiveness of metal matrix composites. The various types of metal matrix composites and their characteristics are described.
Optimal constraint on g{sub NL} from CMB
Sekiguchi, Toyokazu; Sugiyama, Naoshi E-mail: naoshi@nagoya-u.jp
2013-09-01
An optimal method to constrain the non-linearity parameter g{sub NL} of the local-type non-Gaussianity from CMB data is proposed. Our optimal estimator for g{sub NL} is separable and can be efficiently computed in real space. Combining the exact filtering of CMB maps with the full covariance matrix, our method allows us to extract cosmological information from observed data as much as possible and obtain a tighter constraint on g{sub NL} than previous studies. Applying our method to the WMAP 9-year data, we obtain the constraint g{sub NL} = (−3.3±2.2) × 10{sup 5}, which is a few times tighter than previous ones. We also make a forecast for PLANCK data by using the Fisher matrix analysis.
Teaching Tip: When a Matrix and Its Inverse Are Stochastic
ERIC Educational Resources Information Center
Ding, J.; Rhee, N. H.
2013-01-01
A stochastic matrix is a square matrix with nonnegative entries and row sums 1. The simplest example is a permutation matrix, whose rows permute the rows of an identity matrix. A permutation matrix and its inverse are both stochastic. We prove the converse, that is, if a matrix and its inverse are both stochastic, then it is a permutation matrix.
Teaching Tip: When a Matrix and Its Inverse Are Stochastic
ERIC Educational Resources Information Center
Ding, J.; Rhee, N. H.
2013-01-01
A stochastic matrix is a square matrix with nonnegative entries and row sums 1. The simplest example is a permutation matrix, whose rows permute the rows of an identity matrix. A permutation matrix and its inverse are both stochastic. We prove the converse, that is, if a matrix and its inverse are both stochastic, then it is a permutation matrix.
Regenerator matrix physical property data
NASA Technical Reports Server (NTRS)
Fucinari, C. A.
1980-01-01
Among several cellular ceramic structures manufactured by various suppliers for regenerator application in a gas turbine engine, three have the best potential for achieving durability and performance objectives for use in gas turbines, Stirling engines, and waste heat recovery systems: (1) an aluminum-silicate sinusoidal flow passage made from a corrugated wate paper process; (2) an extruded isosceles triangle flow passage; and (3) a second generation matrix incorporating a square flow passage formed by an embossing process. Key physical and thermal property data for these configurations presented include: heat transfer and pressure drop characteristics, compressive strength, tensile strength and elasticity, thermal expansion characteristics, chanical attack, and thermal stability.
Neonatal disorders of germinal matrix.
Raets, M M A; Dudink, J; Govaert, P
2015-11-01
The germinal matrix (GM) is a richly vascularized, transient layer near the ventricles. It produces neurons and glial cells, and is present in the foetal brain between 8 and 36 weeks of gestation. At 25 weeks, it reaches its maximum volume and subsequently withers. The GM is vulnerable to haemorrhage in preterm infants. This selective vulnerability is explained by limited astrocyte end-feet coverage of microvessels, reduced expression of fibronectin and immature tight junctions. Focal lesions in the neonatal period include haemorrhage, germinolysis and stroke. Such lesions in transient layers interrupt normal brain maturation and induce neurodevelopmental sequelae.
Diffusive dynamics on paper matrix
NASA Astrophysics Data System (ADS)
Chaudhury, Kaustav; Kar, Shantimoy; Chakraborty, Suman
2016-11-01
Writing with ink on a paper and the rapid diagnostics of diseases using paper cartridge, despite their remarkable diversities from application perspective, both involve the motion of a liquid from a source on a porous hydrophilic substrate. Here we bring out a generalization in the pertinent dynamics by appealing to the concerned ensemble-averaged transport with reference to the underlying molecular picture. Our results reveal that notwithstanding the associated complexities and diversities, the resultant liquid transport characteristics on a paper matrix, in a wide variety of applications, resemble universal diffusive dynamics. Agreement with experimental results from diversified applications is generic and validates our unified theory.
Matrix management for aerospace 2000
NASA Technical Reports Server (NTRS)
Mccarthy, J. F., Jr.
1980-01-01
The martix management approach to program management is an organized effort for attaining program objectives by defining and structuring all elements so as to form a single system whose parts are united by interaction. The objective of the systems approach is uncompromisingly complete coverage of the program management endeavor. Starting with an analysis of the functions necessary to carry out a given program, a model must be defined; a matrix of responsibility assignment must be prepared; and each operational process must be examined to establish how it is to be carried out and how it relates to all other processes.
Random matrix theory within superstatistics.
Abul-Magd, A Y
2005-12-01
We propose a generalization of the random matrix theory following the basic prescription of the recently suggested concept of superstatistics. Spectral characteristics of systems with mixed regular-chaotic dynamics are expressed as weighted averages of the corresponding quantities in the standard theory assuming that the mean level spacing itself is a stochastic variable. We illustrate the method by calculating the level density, the nearest-neighbor-spacing distributions, and the two-level correlation functions for systems in transition from order to chaos. The calculated spacing distribution fits the resonance statistics of random binary networks obtained in a recent numerical experiment.
Fiber-matrix interface failures
NASA Technical Reports Server (NTRS)
Rabenberg, Lew; Marcus, Harris L.; Park, Hun Sub; Zong, Gui Sheng; Brown, Lloyd D.
1989-01-01
Interface fractures of aluminum-graphite composites under transverse loading are expected to occur within the graphite fibers, but very near the interface. Residual stresses in aluminum, reinforced with the new high modulus pitch-based fibers, are much lower than would be expected based on simple elasticity calculations. The excess stress may be relaxed by shearing internal to the fibers or at the interface rather than by plastic flow of the matrix. The internal shearing also occurs during repeated thermal cycling of these composites; the fibers are repeatedly intruded, then extruded, during repeated temperature excursions.
Thermodynamics of protein folding: a random matrix formulation.
Shukla, Pragya
2010-10-20
The process of protein folding from an unfolded state to a biologically active, folded conformation is governed by many parameters, e.g. the sequence of amino acids, intermolecular interactions, the solvent, temperature and chaperon molecules. Our study, based on random matrix modeling of the interactions, shows, however, that the evolution of the statistical measures, e.g. Gibbs free energy, heat capacity, and entropy, is single parametric. The information can explain the selection of specific folding pathways from an infinite number of possible ways as well as other folding characteristics observed in computer simulation studies.
The q-Laguerre matrix polynomials.
Salem, Ahmed
2016-01-01
The Laguerre polynomials have been extended to Laguerre matrix polynomials by means of studying certain second-order matrix differential equation. In this paper, certain second-order matrix q-difference equation is investigated and solved. Its solution gives a generalized of the q-Laguerre polynomials in matrix variable. Four generating functions of this matrix polynomials are investigated. Two slightly different explicit forms are introduced. Three-term recurrence relation, Rodrigues-type formula and the q-orthogonality property are given.
PAI-1 -675 4G/5G polymorphism as a prognostic biomarker in breast cancer.
Lei, Haixin; Hemminki, Kari; Johansson, Robert; Altieri, Andrea; Enquist, Kerstin; Henriksson, Roger; Lenner, Per; Försti, Asta
2008-05-01
Extracellular matrix degradation, mediated by the urokinase plasminogen activation (uPA) system, is a critical step in tumor invasion and metastasis. High tumor levels of uPA and its inhibitor PAI-1 have been correlated with poor prognosis in breast cancer. We examined whether genetic variation in the genes of the uPA system affect breast cancer susceptibility and prognosis. We genotyped eight potentially functional single nucleotide polymorphisms (SNPs) in six genes of the uPA system in 959 Swedish breast cancer patients with detailed clinical data and up to 15 years of follow-up together with 952 matched controls. We used the unconditional logistic regression models to evaluate the associations between genotypes and breast cancer risk and tumor characteristics. The Kaplan-Meier method was used to estimate the survival probabilities; the log-rank test was used to test differences between subgroups. None of the SNPs conferred an increased breast cancer risk, but correlation with some traditional prognostic factors was observed for several SNPs. Most importantly, we identified the -675 4G/5G SNP in the PAI-1 gene as a promising prognostic biomarker for breast cancer. Compared to the 4G/4G and 4G/5G genotypes 5G/5G homozygosity correlated significantly with worse survival (RR 2.04, 95% CI 1.45-2.86, P<0.001), especially in patients with more aggressive tumors. 5G/5G homozygotes were also the group with worse survival among lymph node negative cases. Our finding suggests that genotyping PAI-1 -675 4G/5G may help in clinical prognosis of breast cancer.
Matrix management in hospitals: testing theories of matrix structure and development.
Burns, L R
1989-09-01
A study of 315 hospitals with matrix management programs was used to test several hypotheses concerning matrix management advanced by earlier theorists. The study verifies that matrix management involves several distinctive elements that can be scaled to form increasingly complex types of lateral coordinative devices. The scalability of these elements is evident only cross-sectionally. The results show that matrix complexity is not an outcome of program age, nor does matrix complexity at the time of implementation appear to influence program survival. Matrix complexity, finally, is not determined by the organization's task diversity and uncertainty. The results suggest several modifications in prevailing theories of matrix organization.
2009-06-25
41G-101-039 (5-13 Oct 1984) --- Two members of a record seven-person crew are pictured during Intravehicular Activity (IVA) aboard the Earth-orbiting Space Shuttle Challenger. Hold picture with open hand at right center edge. Astronaut David C. Leestma, mission specialist, is at right observing a test by payload specialist Marc Garneau, representing the National Research Council (NRC) of Canada. Garneau spent much of his on-duty time conducting a series of experiments for the NRC. The crew consisted of astronauts Robert L. Crippen, commander; Jon A. McBride, pilot; mission specialist's Kathryn D. Sullivan, Sally K. Ride, and David D. Leestma; Canadian astronaut Marc Garneau, and Paul D. Scully-Power, payload specialist's. EDITOR'S NOTE: The STS-41G mission had the first American female EVA (Sullivan); first seven-person crew; first orbital fuel transfer; and the first Canadian (Garneau).
Matrix stiffening promotes a tumor vasculature phenotype
Bordeleau, Francois; Mason, Brooke N.; Lollis, Emmanuel Macklin; Mazzola, Michael; Zanotelli, Matthew R.; Somasegar, Sahana; Califano, Joseph P.; Montague, Christine; LaValley, Danielle J.; Huynh, John; Mencia-Trinchant, Nuria; Negrón Abril, Yashira L.; Hassane, Duane C.; Bonassar, Lawrence J.; Butcher, Jonathan T.; Weiss, Robert S.; Reinhart-King, Cynthia A.
2017-01-01
Tumor microvasculature tends to be malformed, more permeable, and more tortuous than vessels in healthy tissue, effects that have been largely attributed to up-regulated VEGF expression. However, tumor tissue tends to stiffen during solid tumor progression, and tissue stiffness is known to alter cell behaviors including proliferation, migration, and cell–cell adhesion, which are all requisite for angiogenesis. Using in vitro, in vivo, and ex ovo models, we investigated the effects of matrix stiffness on vessel growth and integrity during angiogenesis. Our data indicate that angiogenic outgrowth, invasion, and neovessel branching increase with matrix cross-linking. These effects are caused by increased matrix stiffness independent of matrix density, because increased matrix density results in decreased angiogenesis. Notably, matrix stiffness up-regulates matrix metalloproteinase (MMP) activity, and inhibiting MMPs significantly reduces angiogenic outgrowth in stiffer cross-linked gels. To investigate the functional significance of altered endothelial cell behavior in response to matrix stiffness, we measured endothelial cell barrier function on substrates mimicking the stiffness of healthy and tumor tissue. Our data indicate that barrier function is impaired and the localization of vascular endothelial cadherin is altered as function of matrix stiffness. These results demonstrate that matrix stiffness, separately from matrix density, can alter vascular growth and integrity, mimicking the changes that exist in tumor vasculature. These data suggest that therapeutically targeting tumor stiffness or the endothelial cell response to tumor stiffening may help restore vessel structure, minimize metastasis, and aid in drug delivery. PMID:28034921
Not Available
1988-12-01
Geothermal District G1 includes 37 northeastern California counties and six geothermal fields: Lake City, Susanville, Litchfield, Wendel, Amedee, and Casa Diablo. Electrical generation from geothermal resources occurs in three of the fields: Wendel, Amedee, and Casa Diablo. Low-temperature geothermal projects are underway throughout the district and are described in a road log format. The ten projects described are located at Big Bend, Glass Mountain, Bieber, Alturas, Cedarville, Lake City, Honey Lake Valley, Greenville, and in Sierra and Mono Counties.
Cloete, Kevin Wesley; Ristow, Peter Gustav; Kasu, Mohaimin; D'Amato, Maria Eugenia
2017-03-01
CE equipment detects and deconvolutes mixtures containing up to six fluorescently labeled DNA fragments. This deconvolution is done by the collection software that requires a spectral calibration file. The calibration file is used to adjust for the overlap that occurs between the emission spectra of fluorescence dyes. All commercial genotyping and sequencing kits require the installation of a corresponding matrix standard to generate a calibration file. Due to the differences in emission spectrum overlap between fluorescent dyes, the application of existing commercial matrix standards to the electrophoretic separation of DNA labeled with other fluorescent dyes can yield undesirable results. Currently, the number of fluorescent dyes available for oligonucleotide labeling surpasses the availability of commercial matrix standards. Therefore, in this study we developed and evaluated a customized matrix standard using ATTO 633, ATTO 565, ATTO 550, ATTO Rho6G, and 6-FAM dyes for which no commercial matrix standard is available. We highlighted the potential genotyping errors of using an incorrect matrix standard by evaluating the relative performance of our custom dye set using six matrix standards. The specific performance of two genotyping kits (UniQTyper™ Y-10 version 1.0 and PowerPlex® Y23 System) was also evaluated using their specific matrix standards. The procedure we followed for the construction of our custom dye matrix standard can be extended to other fluorescent dyes.
Han, Fang; Liu, Han
2017-02-01
Correlation matrix plays a key role in many multivariate methods (e.g., graphical model estimation and factor analysis). The current state-of-the-art in estimating large correlation matrices focuses on the use of Pearson's sample correlation matrix. Although Pearson's sample correlation matrix enjoys various good properties under Gaussian models, its not an effective estimator when facing heavy-tail distributions with possible outliers. As a robust alternative, Han and Liu (2013b) advocated the use of a transformed version of the Kendall's tau sample correlation matrix in estimating high dimensional latent generalized correlation matrix under the transelliptical distribution family (or elliptical copula). The transelliptical family assumes that after unspecified marginal monotone transformations, the data follow an elliptical distribution. In this paper, we study the theoretical properties of the Kendall's tau sample correlation matrix and its transformed version proposed in Han and Liu (2013b) for estimating the population Kendall's tau correlation matrix and the latent Pearson's correlation matrix under both spectral and restricted spectral norms. With regard to the spectral norm, we highlight the role of "effective rank" in quantifying the rate of convergence. With regard to the restricted spectral norm, we for the first time present a "sign subgaussian condition" which is sufficient to guarantee that the rank-based correlation matrix estimator attains the optimal rate of convergence. In both cases, we do not need any moment condition.
Han, Fang; Liu, Han
2016-01-01
Correlation matrix plays a key role in many multivariate methods (e.g., graphical model estimation and factor analysis). The current state-of-the-art in estimating large correlation matrices focuses on the use of Pearson’s sample correlation matrix. Although Pearson’s sample correlation matrix enjoys various good properties under Gaussian models, its not an effective estimator when facing heavy-tail distributions with possible outliers. As a robust alternative, Han and Liu (2013b) advocated the use of a transformed version of the Kendall’s tau sample correlation matrix in estimating high dimensional latent generalized correlation matrix under the transelliptical distribution family (or elliptical copula). The transelliptical family assumes that after unspecified marginal monotone transformations, the data follow an elliptical distribution. In this paper, we study the theoretical properties of the Kendall’s tau sample correlation matrix and its transformed version proposed in Han and Liu (2013b) for estimating the population Kendall’s tau correlation matrix and the latent Pearson’s correlation matrix under both spectral and restricted spectral norms. With regard to the spectral norm, we highlight the role of “effective rank” in quantifying the rate of convergence. With regard to the restricted spectral norm, we for the first time present a “sign subgaussian condition” which is sufficient to guarantee that the rank-based correlation matrix estimator attains the optimal rate of convergence. In both cases, we do not need any moment condition.
NASA Astrophysics Data System (ADS)
de Boer, Jan; de Medeiros, Paul; El-Showk, Sheer; Sinkovics, Annamaria
2008-02-01
We consider an open string version of the topological twist previously proposed for sigma-models with G2 target spaces. We determine the cohomology of open strings states and relate these to geometric deformations of calibrated submanifolds and to flat or anti-self-dual connections on such submanifolds. On associative three-cycles we show that the worldvolume theory is a gauge-fixed Chern-Simons theory coupled to normal deformations of the cycle. For coassociative four-cycles we find a functional that extremizes on anti-self-dual gauge fields. A brane wrapping the whole G2 induces a seven-dimensional associative Chern-Simons theory on the manifold. This theory has already been proposed by Donaldson and Thomas as the higher-dimensional generalization of real Chern-Simons theory. When the G2 manifold has the structure of a Calabi-Yau times a circle, these theories reduce to a combination of the open A-model on special Lagrangians and the open B + B-bar-model on holomorphic submanifolds. We also comment on possible applications of our results.
NASA Technical Reports Server (NTRS)
Dito, Scott J.
2014-01-01
The Universal Propellant Servicing System (UPSS) is a dedicated mobile launcher propellant delivery method that will minimize danger and complexity in order to allow vehicles to be serviced and ultimately launched from a variety of locations previously not seen fit for space launch. The UPPS/G2 project is the development of a model, simulation, and ultimately a working application that will control and monitor the cryogenic fluid delivery to the rocket for testing purposes. To accomplish this, the project is using the programming language/environment Gensym G2. The environment is an all-inclusive application that allows development, testing, modeling, and finally operation of the unique application through graphical and programmatic methods. We have learned G2 through classes and trial-and-error, and are now in the process of building the application that will soon be able to be tested on apparatuses here at Kennedy Space Center, and eventually on the actual unit. The UPSS will bring near-autonomous control of launches to those that need it, as well it will be a great addition to NASA and KSC's operational viability and the opportunity to bring space launches to parts of the world, and in time constraints, once not thought possible.
Link prediction via matrix completion
NASA Astrophysics Data System (ADS)
Pech, Ratha; Hao, Dong; Pan, Liming; Cheng, Hong; Zhou, Tao
2017-02-01
Inspired by the practical importance of social networks, economic networks, biological networks and so on, studies on large and complex networks have attracted a surge of attention in the recent years. Link prediction is a fundamental issue to understand the mechanisms by which new links are added to the networks. We introduce the method of robust principal component analysis (robust PCA) into link prediction, and estimate the missing entries of the adjacency matrix. On the one hand, our algorithm is based on the sparse and low-rank property of the matrix, while, on the other hand, it also performs very well when the network is dense. This is because a relatively dense real network is also sparse in comparison to the complete graph. According to extensive experiments on real networks from disparate fields, when the target network is connected and sufficiently dense, whether it is weighted or unweighted, our method is demonstrated to be very effective and with prediction accuracy being considerably improved compared to many state-of-the-art algorithms.
Matrix metalloproteinases in metabolic syndrome.
Hopps, E; Caimi, G
2012-03-01
Metabolic syndrome is commonly accompanied by an elevated cardiovascular risk with high morbidity and mortality. The alterations of the arterial vasculature begin with endothelial dysfunction and lead to micro- and macrovascular complications. The remodeling of the endothelial basal membrane, that promotes erosion and thrombosis, has a multifactorial pathogenesis that includes leukocyte activation, increased oxidative stress and also an altered matrix metalloproteinases (MMPs) expression. MMPs are endopeptidases which degrade extracellular matrix proteins, such as collagen, gelatins, fibronectin and laminin. They can be secreted by several cells within the vascular wall, but macrophages are determinant in the atherosclerotic plaques. Their activity is regulated by tissue inhibitors of MMP (TIMPs) and also by other molecules, such as plasmin. MMPs could be implicated in plaque instability predisposing to vascular complications. It has been demonstrated that an impaired MMP or TIMP expression is associated with higher risk of all-cause mortality. A large number of studies evaluated MMPs pattern in obesity, diabetes mellitus, arterial hypertension and dyslipidemia, all of which define metabolic syndrome according to several Consensus Statement (i.e. IDF, ATP III, AHA). However, few research have been carried out on subjects with metabolic syndrome. The evidences of an improvement in MMP/TIMP ratio with diet, exercise and medical therapy should encourage further investigations with the intent to contrast the atherosclerotic process and to reduce morbidity and mortality of this kind of patients.
Characterization of Metal Matrix Composites
NASA Technical Reports Server (NTRS)
Daniel, I. M.; Chun, H. J.; Karalekas, D.
1994-01-01
Experimental methods were developed, adapted, and applied to the characterization of a metal matrix composite system, namely, silicon carbide/aluminim (SCS-2/6061 Al), and its constituents. The silicon carbide fiber was characterized by determining its modulus, strength, and coefficient of thermal expansion. The aluminum matrix was characterized thermomechanically up to 399 C (750 F) at two strain rates. The unidirectional SiC/Al composite was characterized mechanically under longitudinal, transverse, and in-plane shear loading up to 399 C (750 F). Isothermal and non-isothermal creep behavior was also measured. The applicability of a proposed set of multifactor thermoviscoplastic nonlinear constitutive relations and a computer code was investigated. Agreement between predictions and experimental results was shown in a few cases. The elastoplastic thermomechanical behavior of the composite was also described by a number of new analytical models developed or adapted for the material system studied. These models include the rule of mixtures, composite cylinder model with various thermoelastoplastic analyses and a model based on average field theory. In most cases satisfactory agreement was demonstrated between analytical predictions and experimental results for the cases of stress-strain behavior and thermal deformation behavior at different temperatures. In addition, some models yielded detailed three-dimensional stress distributions in the constituents within the composite.
Extracellular Matrix and Liver Disease
Arriazu, Elena; Ruiz de Galarreta, Marina; Cubero, Francisco Javier; Varela-Rey, Marta; Pérez de Obanos, María Pilar; Leung, Tung Ming; Lopategi, Aritz; Benedicto, Aitor; Abraham-Enachescu, Ioana
2014-01-01
Abstract Significance: The extracellular matrix (ECM) is a dynamic microenvironment that undergoes continuous remodeling, particularly during injury and wound healing. Chronic liver injury of many different etiologies such as viral hepatitis, alcohol abuse, drug-induced liver injury, obesity and insulin resistance, metabolic disorders, and autoimmune disease is characterized by excessive deposition of ECM proteins in response to persistent liver damage. Critical Issues: This review describes the main collagenous and noncollagenous components from the ECM that play a significant role in pathological matrix deposition during liver disease. We define how increased myofibroblasts (MF) from different origins are at the forefront of liver fibrosis and how liver cell-specific regulation of the complex scarring process occurs. Recent Advances: Particular attention is paid to the role of cytokines, growth factors, reactive oxygen species, and newly identified matricellular proteins in the regulation of fibrillar type I collagen, a field to which our laboratory has significantly contributed over the years. We compile data from recent literature on the potential mechanisms driving fibrosis resolution such as MF’ apoptosis, senescence, and reversal to quiescence. Future Directions: We conclude with a brief description of how epigenetics, an evolving field, can regulate the behavior of MF and of how new “omics” tools may advance our understanding of the mechanisms by which the fibrogenic response to liver injury occurs. Antioxid. Redox Signal. 21, 1078–1097. PMID:24219114
Bohn, Mark S.; Anselmo, Mark
2001-01-01
Computer simulation was used in the development of an inward-burning, radial matrix gas burner and heat pipe heat exchanger. The burner and exchanger can be used to heat a Stirling engine on cloudy days when a solar dish, the normal source of heat, cannot be used. Geometrical requirements of the application forced the use of the inward burning approach, which presents difficulty in achieving a good flow distribution and air/fuel mixing. The present invention solved the problem by providing a plenum with just the right properties, which include good flow distribution and good air/fuel mixing with minimum residence time. CFD simulations were also used to help design the primary heat exchanger needed for this application which includes a plurality of pins emanating from the heat pipe. The system uses multiple inlet ports, an extended distance from the fuel inlet to the burner matrix, flow divider vanes, and a ring-shaped, porous grid to obtain a high-temperature uniform-heat radial burner. Ideal applications include dish/Stirling engines, steam reforming of hydrocarbons, glass working, and any process requiring high temperature heating of the outside surface of a cylindrical surface.
Guillong, M.; Hametner, K.; Reusser, E.; Wilson, S.A.; Gunther, D.
2005-01-01
New glass reference materials GSA-1G, GSC-1G, GSD-1G and GSE-1G have been characterised using a prototype solid state laser ablation system capable of producing wavelengths of 193 nm, 213 nm and 266 nm. This system allowed comparison of the effects of different laser wavelengths under nearly identical ablation and ICP operating conditions. The wavelengths 213 nm and 266 nm were also used at higher energy densities to evaluate the influence of energy density on quantitative analysis. In addition, the glass reference materials were analysed using commercially available 266 nm Nd:YAG and 193 nm ArF excimer lasers. Laser ablation analysis was carried out using both single spot and scanning mode ablation. Using laser ablation ICP-MS, concentrations of fifty-eight elements were determined with external calibration to the NIST SRM 610 glass reference material. Instead of applying the more common internal standardisation procedure, the total concentration of all element oxide concentrations was normalised to 100%. Major element concentrations were compared with those determined by electron microprobe. In addition to NIST SRM 610 for external calibration, USGS BCR-2G was used as a more closely matrix-matched reference material in order to compare the effect of matrix-matched and non matrix-matched calibration on quantitative analysis. The results show that the various laser wavelengths and energy densities applied produced similar results, with the exception of scanning mode ablation at 266 nm without matrix-matched calibration where deviations up to 60% from the average were found. However, results acquired using a scanning mode with a matrix-matched calibration agreed with results obtained by spot analysis. The increased abundance of large particles produced when using a scanning ablation mode with NIST SRM 610, is responsible for elemental fractionation effects caused by incomplete vaporisation of large particles in the ICP.
Automatic Generation of Partitioned Matrix Expressions for Matrix Operations
NASA Astrophysics Data System (ADS)
Fabregat-Traver, Diego; Bientinesi, Paolo
2010-09-01
We target the automatic generation of formally correct algorithms and routines for linear algebra operations. Given the broad variety of architectures and configurations with which scientists deal, there does not exist one algorithmic variant that is suitable for all scenarios. Therefore, we aim to generate a family of algorithmic variants to attain high-performance for a broad set of scenarios. One of the authors has previously demonstrated that automatic derivation of a family of algorithms is possible when the Partitioned Matrix Expression (PME) of the target operation is available. The PME is a recursive definition that states the relations between submatrices in the input and the output operands. In this paper we describe all the steps involved in the automatic derivation of PMEs, thus making progress towards a fully automated system.
A Case of Extreme Simplicity of the Core Matrix in Three-Mode Principal Components Analysis.
ERIC Educational Resources Information Center
Murakami, Takashi; ten Berge, Jos M. F.; Kiers, Henk A. L.
1998-01-01
In three-mode principal components analysis, the P x Q x R core matrix "G" can be transformed to simple structure before it is interpreted. This paper shows that, when P=QR-1, G can be transformed to have nearly all the elements equal to values specified a priori. A closed-form solution for this transformation is offered. (SLD)
A Case of Extreme Simplicity of the Core Matrix in Three-Mode Principal Components Analysis.
ERIC Educational Resources Information Center
Murakami, Takashi; ten Berge, Jos M. F.; Kiers, Henk A. L.
1998-01-01
In three-mode principal components analysis, the P x Q x R core matrix "G" can be transformed to simple structure before it is interpreted. This paper shows that, when P=QR-1, G can be transformed to have nearly all the elements equal to values specified a priori. A closed-form solution for this transformation is offered. (SLD)
1990-12-07
Technology, Haifa, 1968. 45 10. Bhatia , Rajendra , Perturbation Bounds for Matrix Eigenvalues, Pitman Research Notes in Mathematics, H. Brezis, R. G. Douglas...is currently in press in the SIAM Journal of Matrix Analysis . The proof sheets have been corrected and returned to the editor during the period of this...appear. [3] R. A. Horn and C. R. Johnson, Matrix Analysis , Cambridge University Press, New York, 1985. 141 M. Marcus and N. Khan, A note on the
Scatter polarization measurements with a mueller matrix imaging polarimeter.
Chipman, Russell A.; DeBoo, Brian
2004-08-01
A Mueller matrix imaging polarimeter is used to acquire polarization-sensitive images of seven different manmade samples in multiple scattering geometries. Successive Mueller matrix images of a sample with changing incidence and scatter angles are used to develop a Mueller matrix bidirectional reflectance distribution function for the sample in one plane of measurement. The Mueller matrix bidirectional reflectance distribution functions are compared, and patterns are noted. The most significant data for the scattering samples measured occurs along the diagonal of the respective Mueller matrices, indicating significant depolarization effects. Reduced depolarization data in the form of the average degree of polarization (of exiting light) for each sample is examined as a function of changing scattering geometry. Five of seven manmade samples exhibit an inverted Gaussian profile of depolarization with changing scattering geometry, the shape of which may prove useful for measuring sample properties (e.g. roughness) and for classifying or categorizing samples in a remote sensing scheme. Depolarization differences for each sample in response to changing incident polarization states are also examined, and a new metric, the degree of polarization surface, has been developed to visualize all such data simultaneously.
Two modulator generalized ellipsometer for complete mueller matrix measurement
Jellison, Jr., Gerald E.; Modine, Frank A.
1999-01-01
A two-modulator generalized ellipsometer (2-MGE) comprising two polarizer-photoelastic modulator (PEM) pairs, an optical light source, an optical detection system, and associated data processing and control electronics, where the PEMs are free-running. The input light passes through the first polarizer-PEM pair, reflects off the sample surface or passes through the sample, passes through the second PEM-polarizer pair, and is detected. Each PEM is free running and operates at a different resonant frequency, e.g., 50 and 60 kHz. The resulting time-dependent waveform of the light intensity is a complicated function of time, and depends upon the exact operating frequency and phase of each PEM, the sample, and the azimuthal angles of the polarizer-PEM pairs, but can be resolved into a dc component and eight periodic components. In one embodiment, the waveform is analyzed using a new spectral analysis technique that is similar to Fourier analysis to determine eight sample Mueller matrix elements (normalized to the m.sub.00 Mueller matrix element). The other seven normalized elements of the general 4.times.4 Mueller matrix can be determined by changing the azimuthal angles of the PEM-polarizer pairs with respect to the plane of incidence. Since this instrument can measure all elements of the sample Mueller matrix, it is much more powerful than standard ellipsometers.
Reverse Watson-Crick G-G base pair in G-quadruplex formation.
Mondal, Soma; Bhat, Jyotsna; Jana, Jagannath; Mukherjee, Meghomukta; Chatterjee, Subhrangsu
2016-01-01
A stable intermediate dimeric G-rich form as a precursor of tetrameric G-quadruplex structures has been detected via MALDI-TOF spectrometry. Molecular dynamics simulation offered detailed insights at the atomic level, assigning reverse Watson-Crick G-G base pairing (not Hoogsteen) in the G-rich dimer. In support of this, cisplatin formed a stable adduct by binding to the dimeric G-rich structure, eliminating the possibility of G-G Hoogsteen hydrogen bond formation.
NASA Technical Reports Server (NTRS)
Mach, D. M.; Koshak, W. J.
2007-01-01
A matrix calibration procedure has been developed that uniquely relates the electric fields measured at the aircraft with the external vector electric field and net aircraft charge. The calibration method can be generalized to any reasonable combination of electric field measurements and aircraft. A calibration matrix is determined for each aircraft that represents the individual instrument responses to the external electric field. The aircraft geometry and configuration of field mills (FMs) uniquely define the matrix. The matrix can then be inverted to determine the external electric field and net aircraft charge from the FM outputs. A distinct advantage of the method is that if one or more FMs need to be eliminated or deemphasized [e.g., due to a malfunction), it is a simple matter to reinvert the matrix without the malfunctioning FMs. To demonstrate the calibration technique, data are presented from several aircraft programs (ER-2, DC-8, Altus, and Citation).
7 CFR Exhibit G to Subpart G of... - [Reserved
Code of Federal Regulations, 2010 CFR
2010-01-01
... 7 Agriculture 13 2010-01-01 2009-01-01 true [Reserved] G Exhibit G to Subpart G of Part 1940 Agriculture Regulations of the Department of Agriculture (Continued) RURAL HOUSING SERVICE, RURAL BUSINESS...) PROGRAM REGULATIONS (CONTINUED) GENERAL Environmental Program Exhibit G to Subpart G of Part 1940...
Evaluation of metal matrix composites
NASA Technical Reports Server (NTRS)
Okelly, K. P.
1971-01-01
The results of an evaluation of candidate metal-matrix composite materials for shuttle space radiators mounted to external structure are presented. The evaluation was specifically applicable to considerations of the manufacturing and properties of a potential space radiator. Two candidates, boron/aluminum and graphite/aluminum were obtained or made in various forms and tested in sufficient depth to allow selection of one of the two for future scale-up programs. The effort accomplished on this program verified that aluminum reinforced with boron was within the state-of-the-art in industry and possessed properties usable in the external skin areas available for shuttle radiators where re-entry temperatures will not exceed 800 F. It further demonstrated that graphite/aluminum has an apparently attractive future for space applications but requires extension development prior to scale-up.
Superfund chemical data matrix, 1996
1996-06-01
The Superfund Chemical Data Matrix (SCDM) is a source for factor values and benchmark values applied when evaluating potential National Priorities List (NPL) sites using the Hazard Ranking System. The HRS assigns factor values for toxicity, gas migration potential, gas and ground water mobility, surface water persistence, and bioaccumulation potential based on the physical, chemical, and radiological properties of hazardous substances present at a site. Hazardous substances, as defined for HRS purposes, are CERCLA hazardous substances plus CERCLA pollutants and contaminants. The HRS also assigns extra weight to targets with exposure levels to hazardous substances that are at or above benchmarks. These benchmarks include both risk-based screening concentrations and concentrations specified in regulatory limits for the hazardous substances present at a site for a particular migration pathway.
Applications of matrix inversion tomosynthesis
NASA Astrophysics Data System (ADS)
Warp, Richard J.; Godfrey, Devon J.; Dobbins, James T., III
2000-04-01
The improved image quality and characteristics of new flat- panel x-ray detectors have renewed interest in advanced algorithms such as tomosynthesis. Digital tomosynthesis is a method of acquiring and reconstructing a three-dimensional data set with limited-angle tube movement. Historically, conventional tomosynthesis reconstruction has suffered contamination of the planes of interest by blurred out-of- plane structures. This paper focuses on a Matrix Inversion Tomosynthesis (MITS) algorithm to remove unwanted blur from adjacent planes. The algorithm uses a set of coupled equations to solve for the blurring function in each reconstructed plane. This paper demonstrates the use of the MITS algorithm in three imaging applications: small animal microscopy, chest radiography, and orthopedics. The results of the MITS reconstruction process demonstrate an improved reduction of blur from out-of-plane structures when compared to conventional tomosynthesis. We conclude that the MITS algorithm holds potential in a variety of applications to improve three-dimensional image reconstruction.
Continuous analogues of matrix factorizations
Townsend, Alex; Trefethen, Lloyd N.
2015-01-01
Analogues of singular value decomposition (SVD), QR, LU and Cholesky factorizations are presented for problems in which the usual discrete matrix is replaced by a ‘quasimatrix’, continuous in one dimension, or a ‘cmatrix’, continuous in both dimensions. Two challenges arise: the generalization of the notions of triangular structure and row and column pivoting to continuous variables (required in all cases except the SVD, and far from obvious), and the convergence of the infinite series that define the cmatrix factorizations. Our generalizations of triangularity and pivoting are based on a new notion of a ‘triangular quasimatrix’. Concerning convergence of the series, we prove theorems asserting convergence provided the functions involved are sufficiently smooth. PMID:25568618
Thermoplastic matrix composite processing model
NASA Technical Reports Server (NTRS)
Dara, P. H.; Loos, A. C.
1985-01-01
The effects the processing parameters pressure, temperature, and time have on the quality of continuous graphite fiber reinforced thermoplastic matrix composites were quantitatively accessed by defining the extent to which intimate contact and bond formation has occurred at successive ply interfaces. Two models are presented predicting the extents to which the ply interfaces have achieved intimate contact and cohesive strength. The models are based on experimental observation of compression molded laminates and neat resin conditions, respectively. Identified as the mechanism explaining the phenomenon by which the plies bond to themselves is the theory of autohesion (or self diffusion). Theoretical predictions from the Reptation Theory between autohesive strength and contact time are used to explain the effects of the processing parameters on the observed experimental strengths. The application of a time-temperature relationship for autohesive strength predictions is evaluated. A viscoelastic compression molding model of a tow was developed to explain the phenomenon by which the prepreg ply interfaces develop intimate contact.
NASA Astrophysics Data System (ADS)
Ghazi, A. A.; Qamar, Sajid; Atta, M. A.
1993-08-01
Maximum allowable concentrations of 12 elements in uranium hexafluoride feed for enrichment to reactor grade material (about 3%), vary from 1 to 100 ppm ( μg/g). Using an inductively coupled plasma atomic emission spectrometer, 51 lines of ten of these elements (B, Cr, Mo, P, Sb, Si, Ta, Ti, V and W) have been studied with a uranium matrix to investigate the matrix interference on the basis of signal to background (SBR), and background to background ratios (BBR). Detection limits and limits of quantitative determination (LQDs) were calculated for these elements in a uranium matrix using SBR and relative standard deviation of the background signal (RSD B) approach. In almost all cases, the uranium matrix interference reduces the SBRs to the extent that direct trace analysis is impossible. A uranium sample having known concentrations of impurities (around LQDs) was directly analysed with results that showed reasonable accuracy and precision.
Penicillin G Benzathine and Penicillin G Procaine Injection
... to treat and prevent certain infections caused by bacteria. Penicillin G benzathine and penicillin G procaine injection ... of medications called penicillins. It works by killing bacteria that cause infections.Antibiotics such as penicillin G ...
Thermophysical and Electrical Properties of Metal Matrix Composites
1979-12-01
de if necessary and identify by block number) Aluminum matrix composiles, aluminum alloy matrix composites, copper matrix composites, electrical...the various com- posites of aluminum and aluminum alloy mar-tices, copper matrix, lead matrix, magnesium matrix, nickel and nickel alloy matrices...titanium and titanium alloy matrices, tungsten matrix, and zinc matrix. Most of the data are for aluminum DD j JAN 73 1473 EDITION OF I NOV6 S IS
Modified matrix volatilization setup for characterization of high purity germanium.
Meruva, Adisesha Reddy; Raparthi, Shekhar; Kumar, Sunil Jai
2016-01-01
Modified matrix volatilization (MV) method has been described to characterize high purity germanium material of 7 N (99.99999%) purity. Transport of both, the chlorine gas generated in-situ in this method and the argon gas (carrier) is fine controlled by means of a mass flow controller. This enabled both uniform reaction of chlorine gas with the germanium matrix and smooth removal of germanium matrix as its chloride. This resulted in improvement in the reproducibility of the analytical results. The use of quartz reaction vessel has lead to the reduction in the process blank levels. The combined effect of these modifications in the MV setup has resulted in very consistent and low process blanks and hence improved detection limits of this method. Applicability of the method has been expanded to rare earth elements and other elements after examining their recoveries. The quantification is done by using inductively coupled plasma quadrupole mass spectrometer (ICP-QMS) and continuum source graphite furnace atomic absorption spectrometry (CS-GFAAS). In the absence of certified reference materials for high pure germanium, the accuracy of the method is established by spike recovery tests. The precision of the method has been found to vary from 1 to 30% for concentrations between 1 and 30 ng g(-1). The limits of detection (LOD) for the target analytes are found to be between 18 and 0.033 ng g(-1). Copyright © 2015 Elsevier B.V. All rights reserved.
Convex nonnegative matrix factorization with manifold regularization.
Hu, Wenjun; Choi, Kup-Sze; Wang, Peiliang; Jiang, Yunliang; Wang, Shitong
2015-03-01
Nonnegative Matrix Factorization (NMF) has been extensively applied in many areas, including computer vision, pattern recognition, text mining, and signal processing. However, nonnegative entries are usually required for the data matrix in NMF, which limits its application. Besides, while the basis and encoding vectors obtained by NMF can represent the original data in low dimension, the representations do not always reflect the intrinsic geometric structure embedded in the data. Motivated by manifold learning and Convex NMF (CNMF), we propose a novel matrix factorization method called Graph Regularized and Convex Nonnegative Matrix Factorization (GCNMF) by introducing a graph regularized term into CNMF. The proposed matrix factorization technique not only inherits the intrinsic low-dimensional manifold structure, but also allows the processing of mixed-sign data matrix. Clustering experiments on nonnegative and mixed-sign real-world data sets are conducted to demonstrate the effectiveness of the proposed method. Copyright © 2014 Elsevier Ltd. All rights reserved.
Eigenvalues properties of terms correspondences matrix
NASA Astrophysics Data System (ADS)
Bondarchuk, Dmitry; Timofeeva, Galina
2016-12-01
Vector model representations of text documents are widely used in the intelligent search. In this approach a collection of documents is represented in the form of the term-document matrix, reflecting the frequency of terms. In the latent semantic analysis the dimension of the vector space is reduced by the singular value decomposition of the term-document matrix. Authors use a matrix of terms correspondences, reflecting the relationship between the terms, to allocate a semantic core and to obtain more simple presentation of the documents. With this approach, reducing the number of terms is based on the orthogonal decomposition of the matrix of terms correspondences. Properties of singular values of the term-document matrix and eigenvalues of the matrix of terms correspondences are studied in the case when documents differ substantially in length.
Fission Matrix Capability for MCNP Monte Carlo
NASA Astrophysics Data System (ADS)
Brown, Forrest; Carney, Sean; Kiedrowski, Brian; Martin, William
2014-06-01
We describe recent experience and results from implementing a fission matrix capability into the MCNP Monte Carlo code. The fission matrix can be used to provide estimates of the fundamental mode fission distribution, the dominance ratio, the eigenvalue spectrum, and higher mode forward and adjoint eigenfunctions of the fission neutron source distribution. It can also be used to accelerate the convergence of the power method iterations and to provide basis functions for higher-order perturbation theory. The higher-mode fission sources can be used in MCNP to determine higher-mode forward fluxes and tallies, and work is underway to provide higher-mode adjoint-weighted fluxes and tallies. Past difficulties and limitations of the fission matrix approach are overcome with a new sparse representation of the matrix, permitting much larger and more accurate fission matrix representations. The new fission matrix capabilities provide a significant advance in the state-of-the-art for Monte Carlo criticality calculations.
Characterizing damage in ceramic matrix composites
NASA Astrophysics Data System (ADS)
Gyekenyesi, Andrew L.; Baker, Christopher; Morscher, Gregory
2014-04-01
With the upcoming implementation of ceramic matrix composites (CMCs) within aerospace systems (e.g., aviation turbine engines), an in-depth understanding of the failure process due to mechanical loads is required. This includes developing a basic understanding of the complex, multi-mechanism failure process as well as the associated nondestructive evaluation (NDE) techniques that are capable of recognizing and quantifying the damage. Various NDE techniques have been successfully utilized for assessing the damage state of woven CMCs, in particular, consisting of silicon carbide fibers and silicon carbide matrices (SiC/SiC). The multiple NDE techniques, studied by the authors of this paper, included acousto-ultrasonics, modal acoustic emissions, electrical resistance, impedance based structural health monitoring, pulsed thermography as well as thermoelastic stress analysis. The observed damage within the composites was introduced using multiple experimental tactics including uniaxial tensile tests, creep tests, and most recently, ballistic impact. This paper offers a brief review and summary of results for each of the applied NDE tools.
NASA Technical Reports Server (NTRS)
Pohorille, Andrew
2005-01-01
Life is based on non-covalent interactions. They might be either specific (enzyme-substrate interactions, selective ion transport) or nonspecific (lipid-lipid and lipid-protein interactions needed for membrane integrity, fusion and division). Their strength needs to be properly tuned, and this is mediated by the solvent. If interactions are too weak, there might be undesired response to natural fluctuations of physical and chemical parameters. If they are too strong it could impede kinetics and energetics of cellular processes. Thus, the solvent must allow for balancing these interactions. Physical and chemical properties of solvent provide strong constraints for life. Water exhibits a remarkable trait that it promotes both solvophobic and solvophilic interactions. Solvophobic interactions; related to high dielectric constant of the solvent) are necessary for self-organization of matter whereas solvophilic interactions are needed to ensure solubility of polar species. Water offers a large temperature domain of stable liquid and the characteristics hydrophobic effects are a consequence of the temperature in sensitivity of essential properties of its liquid state. Water, however, is not the only liquid with these favorable properties. I will compare in detail properties of water and other pure liquids or their mixtures that have a high dielectric constant and simultaneously support self-organization. I will also discuss properties of water that are unfavorable to life (e.g. its chemical activity against polymerization reactions) and close with summarizing what are alternatives to water as a matrix of life in space.
Metal-Matrix/Hollow-Ceramic-Sphere Composites
NASA Technical Reports Server (NTRS)
Baker, Dean M.
2011-01-01
A family of metal/ceramic composite materials has been developed that are relatively inexpensive, lightweight alternatives to structural materials that are typified by beryllium, aluminum, and graphite/epoxy composites. These metal/ceramic composites were originally intended to replace beryllium (which is toxic and expensive) as a structural material for lightweight mirrors for aerospace applications. These materials also have potential utility in automotive and many other terrestrial applications in which there are requirements for lightweight materials that have high strengths and other tailorable properties as described below. The ceramic component of a material in this family consists of hollow ceramic spheres that have been formulated to be lightweight (0.5 g/cm3) and have high crush strength [40.80 ksi (.276.552 MPa)]. The hollow spheres are coated with a metal to enhance a specific performance . such as shielding against radiation (cosmic rays or x rays) or against electromagnetic interference at radio and lower frequencies, or a material to reduce the coefficient of thermal expansion (CTE) of the final composite material, and/or materials to mitigate any mismatch between the spheres and the matrix metal. Because of the high crush strength of the spheres, the initial composite workpiece can be forged or extruded into a high-strength part. The total time taken in processing from the raw ingredients to a finished part is typically 10 to 14 days depending on machining required.
NASA Technical Reports Server (NTRS)
Pohorille, Andrew
2005-01-01
Life is based on non-covalent interactions. They might be either specific (enzyme-substrate interactions, selective ion transport) or nonspecific (lipid-lipid and lipid-protein interactions needed for membrane integrity, fusion and division). Their strength needs to be properly tuned, and this is mediated by the solvent. If interactions are too weak, there might be undesired response to natural fluctuations of physical and chemical parameters. If they are too strong it could impede kinetics and energetics of cellular processes. Thus, the solvent must allow for balancing these interactions. Physical and chemical properties of solvent provide strong constraints for life. Water exhibits a remarkable trait that it promotes both solvophobic and solvophilic interactions. Solvophobic interactions; related to high dielectric constant of the solvent) are necessary for self-organization of matter whereas solvophilic interactions are needed to ensure solubility of polar species. Water offers a large temperature domain of stable liquid and the characteristics hydrophobic effects are a consequence of the temperature in sensitivity of essential properties of its liquid state. Water, however, is not the only liquid with these favorable properties. I will compare in detail properties of water and other pure liquids or their mixtures that have a high dielectric constant and simultaneously support self-organization. I will also discuss properties of water that are unfavorable to life (e.g. its chemical activity against polymerization reactions) and close with summarizing what are alternatives to water as a matrix of life in space.
Optical properties of matrix confined species
NASA Astrophysics Data System (ADS)
Lezhnina, M. M.; Kynast, U. H.
2010-11-01
A majority of optically functional materials can be perceived as a liaison between ionic or molecular guests and a more or less rigid host. The guests exhibit an optical function, whereas the host provides suitable space, both of them synergistically complementing each other. The embracement of guests and hosts is often very intimate, as e.g. in typical phosphors, where luminescent ions even become part of the host. While the host-guest terminology usually is not applied to such marriages, the term becomes appropriate, if the host grants some degrees of spatial freedom, yet giving order and structure to its guests. Zeolites, clays and inverse opals are porous materials naturally providing hospitable cavities, channels or other compartments, and at the same time the guests are often demanded to occupy preassigned positions within these, or to structurally adapt to the interior host topology. Whereas zeolites and clays are merely patient providers of guest space, inverse opals, can actively turn the light on and off. The present article summarises and highlights recent experimental evidence, ongoing research and some envisaged merits resulting from the interaction of matrix confined luminescent ions, complexes and molecules with a focus on the optical properties of rare earth based materials.
NASA Technical Reports Server (NTRS)
Vaughan, M. S.
1972-01-01
Eight different types of low-g accelerometer tests are covered on the Bell miniature electrostatically suspended accelerometer (MESA) which is known to be sensitive to less than 10 to the minus 7th power earth's gravity. These tests include a mass attracting scheme, Leitz dividing head, Wild theodolite, precision gage blocks, precision tiltmeters, Hilger Watts autocollimator, Razdow Mark 2 autocollimator, and laser interferometer measuring system. Each test is described and a comparison of the results is presented. The output of the MESA was as linear and consistent as any of the available devices were capable of measuring. Although the extent of agreement varied with the test equipment used, it can only be concluded that the indicated errors were attributable to the test equipment coupled with the environmental conditions.
NASA Technical Reports Server (NTRS)
1984-01-01
The Crew of STS-41G Challenger Shuttle, Pilot Jon A. McBride, Mission Specialists Kathryn D. Sullivan, Sally K. Ride and David C. Leestma, and Payload Specialists Marc Garmeau, and Paul D. Scully-Power are seen driving in the Astro-van to pick up the Commander of the mission Robert L. Crippen. Footage of the crew arriving at the launch pad, departing the Astro-van and boarding the shuttle to perform a trial countdown demonstration test are shown. Members of the Challenger team are seen exiting the shuttle, and answering questions from reporters. Live footage of the flight control room, and several panoramic views of the shuttle on the launch pad are also seen.
Chenock, T.A.Jr. ); Heshmet, A. )
1990-07-01
The effect of matrix material on the strength, toughness, and fracture behavior of two high temperature polyimide/carbon fiber composites has been studied and compared. The polyimide matrix resins under investigation are PMR-II-20, PMR-15. Each system was reinforced with epoxy sized Celion G30-500 carbon fabric (8HSW, 3K tow). Un-notched and notched specimens were tested under 4-point bend loading in both translaminar and crosslaminar directions.
Suzuki, Yoshitaka; Nishida, Yoshihiro; Naruse, Takahiro; Gemba, Takefumi; Ishiguro, Naoki
2009-03-01
One of the crucial roles of tumor extracellular matrix is to act as a barrier to drug delivery. In this study, we analyzed the relationship between the formation of tumor extracellular matrix and the efficiency of intracellular uptake of oligonucleotides in human osteosarcoma cell lines, HOS, and MG-63. Oligonucleotides used in this study were nuclear factor-kappa B (NF-kappaB) decoy, which might be a therapeutic tool for neoplasms. Pericellular matrix formation was examined by particle exclusion assay. Cellular uptake of fluorescein isothiocyanate-labeled NF-kappaB decoy was evaluated by fluorescent microscopy and flow cytometry. Effects of NF-kappaB decoy on cell viability and cell cycle arrest in MG-63 cells were determined by MTT assay and flow cytometry, respectively. MG-63 cells exhibited abundant pericellular matrix with time compared with HOS cells. Uptake of fluorescein isothiocyanate-labeled NF-kappaB decoy decreased in MG-63 cells with time but not in HOS cells in both monolayer and three-dimensional culture using matrigel. However, after enzymatic removal of pericellular matrix, the uptake markedly recovered in MG-63 cells. NF-kappaB decoy inhibited cell proliferation and induced G0/G1 cell cycle arrest in MG-63 cells. These results suggest that abundant pericellular matrix might disturb the uptake of NF-kappaB decoy, and modification of pericellular matrix composition would increase the efficacy of exogenous oligonucleotides treatment for neoplasms.
Li, Zhen; Ge, Hongzhou; Xie, Yong-Gang; Xie, Guang-Ying; Lv, Chao
2015-03-01
Data on the association between -1607 1G > 2G polymorphism in the promoter region of matrix metalloproteinase-1 (MMP1) and nasopharyngeal carcinoma (NPC) are conflicting. The aim of this study was to confirm whether this polymorphism was a causative factor of NPC. We searched PubMed, Embase, and China National Knowledge Infrastructure (CNKI) for studies on the present topic. A total of four publications (1,044 NPC patients and 1,284 healthy control subjects) were included and meta-analysis was performed to assess the association between -1607 1G > 2G polymorphism and NPC risk. Odds ratio (OR) with 95 % confidence interval (95 % CI) was calculated for 1G1G versus 2G2G, 1G1G + 1G2G versus 2G2G, 1G1G versus 1G2G + 2G2G, 1G versus 2G, and 1G2G versus 2G2G contrast models. Meta-analysis results showed significantly reduced risk of NPC associated with the 1G1G versus 2G2G, 1G versus 2G and 1G2G versus 2G2G contrast models (OR = 0.61, 95 % CI 0.49-0.77; OR = 0.78, 95 % CI 0.65-0.92; OR = 0.86, 95 % CI 0.74-0.99, respectively). When we continued to perform subgroup analysis by ethnicity, the significant association persisted in Asian population and was most pronounced under the 1G2G versus 2G2G model (OR = 0.85, 95 % CI 0.73-0.99). These data suggested that MMP1 -1607 1G > 2G polymorphism was associated with reduced risk of NPC, particularly in the population of Asian descent.
Rims, Matrix and the Bulk Compositions of Ordinary Chondrites
NASA Astrophysics Data System (ADS)
Alexander, C. M. O'd.
1995-09-01
endmember of the rim trend, matrix-like material must have been present during chondrule formation and was, perhaps, efficiently accreted by the chondrules. Two possible explanations for the Al enrichment of matrix are that it is rich either in refractory amorphous condensates or chondrule glass. If volatile losses of even only a few percent were common for chondrules during their formation, there is a third possible explanation. To a first approximation, the fractional mass loss rate of a chondritic particle during evaporation is inversely proportional to its radius. Thus, if the dust (1-10 micrometers) in the chondrule forming region experienced similar conditions to chondrules (100-1000 micrometers), evaporative losses from dust would have been severe. As a result, the dust would have been enriched in refractory elements like Al, perhaps explaining some of the fine-grained corundum and hibonite found in the CAI-poor OCs. If some of this dust was fractionated from the gas and chondrules before much recondensation took place and later mixed in with unprocessed material, the Al enrichment of matrix could be understood. Recondensation and subsequent redistribution in the parent body would explain alkali abundances in matrix. Secondary redistribution may have also produced the fractionation of many refractory elements from Al in UOC and CO3 rims and matrix [4]. The ordinary and enstatite chondrites have bulk compositions that indicate they lost a fraction of their refractory elements. This has always been explained as being due to the loss of refractory nebular condensates. However, evaporative residues of chondritic material can have very similar compositions to condensates. Consequently, if volatilization during chondrule formation was an important process and some of the finer grained material was lost prior to complete recondensation it may be possible to explain rim, matrix and bulk meteorite refractory and common lithophile compositions References: [1] Huss G. R. (1990
Regulation of extracellular matrix biosynthesis by matrix components
Holderbaum, D.; Ehrhart, L.A.
1986-03-01
The authors have previously shown that smooth muscle cells derived from healthy rabbit aortic media synthesize less collagen and fibronectin when grown on culture dishes coated with rabbit plasma fibronectin. In these cultures noncollagen protein synthesis was not affected, suggesting a specific regulatory mechanism. Their current studies expand this observation by examining the ability of proteolytically derived, specific domains of plasma fibronectin to effect decreases in collagen and fibronectin synthesis by cultured arterial smooth muscle. Rabbit plasma fibronectin was digested with bovine ..cap alpha..-chymotrypsin by the method of Hahn and Yamada. The resultant proteolytic fragments were separated by their ability to bind to gelatin-agarose. Culture dishes were coated with either (1) cell binding fragment of fibronectin, (2) gelatin binding fragment, (3) intact fibronectin, (4) type I collagen derived from lathyritic rat skin or (5) bovine serum albumin. Preconfluent cultures were labeled with /sup 3/H-Pro for 24 hr. Fibronectin synthesis was determined by immunoprecipitation of /sup 3/H-fibronectin. Collagen synthesis was measured by monitoring /sup 3/H-Hyp formation. Decreased collagen and fibronectin synthesis was evident in cells grown on intact fibronectin, cell binding fragment of fibronectin and type I collagen. Cells plated on gelatin binding fragment synthesized both collagen and fibronectin at levels comparable to cells on albumin coated dishes. They conclude that the regulatory activity of fibronectin on matrix biosynthesis resides on the cell binding domain of the molecule and that type I collagen can exert a similar effect.
Oxytocin prevents cartilage matrix destruction via regulating matrix metalloproteinases.
Wu, Yixin; Wu, Tongyu; Xu, Binbin; Xu, Xiaoyan; Chen, Honggan; Li, Xiyao
2017-05-06
Degradation of the extracellular matrix type II Collagen (Col II) induced by proinflammatory cytokines such as tumor necrosis factor-α (TNF-α) is an important hallmark of Osteoarthritis (OA). Oxytocin (OT) is a well-known neurohypophysical hormone that is synthesized in the paraventricular (PVN) and supraoptic nuclei (SON) of the hypothalamus. In this study, we have found that oxytocin receptor (OTR) was expressed in human primary chondrocytes, and the expression of which was reduced in chondrocytes from OA patients and in response to TNF-α treatment in a dose dependent manner. Notably, it was shown that TNF-α -induced degradation of Col II was restored by treatment with OT in a dose-dependent manner. In addition, TNF-α treatment (10 ng/mL) highly elevated the expression of MMP-1 and MMP-13 in SW1353 chondrocytes, which were reversed by OT in a dose dependent manner at both gene and protein expression levels. In addition, it was demonstrated that the JAK2/STAT1 pathway was involved in the restoration effects of OT in the degradation of Col II. Lastly, knockdown of OTR abolished the inhibitory effects of OT on the degradation of col II and the induction of MMP-1 and MMP-13 expression, suggesting the involvement of OTR. Our study implied the therapeutic potential of OT for cartilage degradation. Copyright © 2017 Elsevier Inc. All rights reserved.
Stokes scattering matrix for human skin.
Bhandari, Anak; Stamnes, Snorre; Hamre, Børge; Frette, Oyvind; Stamnes, Knut; Stamnes, Jakob J
2012-11-01
We use a layered model of normal human skin based on size distributions of polydisperse spherical particles and their complex refractive indices to compute the Stokes scattering matrix at wavelengths in the visible spectral band. The elements of the Stokes scattering matrix are required in a polarized radiative transfer code for a coupled air-tissue system to compute the polarized reflectance and examine how it is dependent on the vertical structure of the inherent optical properties of skin, including the phase matrix. Thus, the elements of the Stokes scattering matrix can be useful for investigating polarization-dependent light propagation in turbid optical media, such as human skin tissue.
Finding Nonoverlapping Substructures of a Sparse Matrix
Pinar, Ali; Vassilevska, Virginia
2005-08-11
Many applications of scientific computing rely on computations on sparse matrices. The design of efficient implementations of sparse matrix kernels is crucial for the overall efficiency of these applications. Due to the high compute-to-memory ratio and irregular memory access patterns, the performance of sparse matrix kernels is often far away from the peak performance on a modern processor. Alternative data structures have been proposed, which split the original matrix A into A{sub d} and A{sub s}, so that A{sub d} contains all dense blocks of a specified size in the matrix, and A{sub s} contains the remaining entries. This enables the use of dense matrix kernels on the entries of A{sub d} producing better memory performance. In this work, we study the problem of finding a maximum number of nonoverlapping dense blocks in a sparse matrix, which is previously not studied in the sparse matrix community. We show that the maximum nonoverlapping dense blocks problem is NP-complete by using a reduction from the maximum independent set problem on cubic planar graphs. We also propose a 2/3-approximation algorithm that runs in linear time in the number of nonzeros in the matrix. This extended abstract focuses on our results for 2x2 dense blocks. However we show that our results can be generalized to arbitrary sized dense blocks, and many other oriented substructures, which can be exploited to improve the memory performance of sparse matrix operations.
Multiscale Modeling of Ceramic Matrix Composites
NASA Technical Reports Server (NTRS)
Bednarcyk, Brett A.; Mital, Subodh K.; Pineda, Evan J.; Arnold, Steven M.
2015-01-01
Results of multiscale modeling simulations of the nonlinear response of SiC/SiC ceramic matrix composites are reported, wherein the microstructure of the ceramic matrix is captured. This micro scale architecture, which contains free Si material as well as the SiC ceramic, is responsible for residual stresses that play an important role in the subsequent thermo-mechanical behavior of the SiC/SiC composite. Using the novel Multiscale Generalized Method of Cells recursive micromechanics theory, the microstructure of the matrix, as well as the microstructure of the composite (fiber and matrix) can be captured.
Matrix metalloproteinases in destructive lung disease.
Houghton, A McGarry
2015-01-01
Matrix metalloproteinases (MMPs) play essential physiologic roles in numerous processes ranging from development to wound repair. Unfortunately, given the broad substrate specificity of the MMP family as a whole, aberrant degradation of extracellular matrix proteins can result in destructive disease. Emphysema, the result of destroyed lung elastin and collagen matrix, is the prototypical example of such a destructive process. More recent data has highlighted that MMPs play much more elaborate physiologic and pathophysiologic roles than simple matrix protein cleavage. Key pathophysiological roles for MMPs in emphysema will be discussed herein.
Reconstituted asbestos matrix for fuel cells
NASA Technical Reports Server (NTRS)
Mcbryar, H.
1975-01-01
Method is described for reprocessing commercially available asbestos matrix stock to yield greater porosity and bubble pressure (due to increased surface tension), improved homogeneity, and greater uniformity.
Extracellular Matrix: Functions in the Nervous System
Barros, Claudia S.; Franco, Santos J.; Müller, Ulrich
2011-01-01
An astonishing number of extracellular matrix glycoproteins are expressed in dynamic patterns in the developing and adult nervous system. Neural stem cells, neurons, and glia express receptors that mediate interactions with specific extracellular matrix molecules. Functional studies in vitro and genetic studies in mice have provided evidence that the extracellular matrix affects virtually all aspects of nervous system development and function. Here we will summarize recent findings that have shed light on the specific functions of defined extracellular matrix molecules on such diverse processes as neural stem cell differentiation, neuronal migration, the formation of axonal tracts, and the maturation and function of synapses in the peripheral and central nervous system. PMID:21123393
Evaluating wilderness recreational opportunities: application of an impact matrix
Stohlgren, Thomas J.; Parsons, David J.
1992-01-01
An inventory of the severity and spatial distribution of wilderness campsite impacts in Sequoia and Kings Canyon National Parks identified a total of 273 distinct nodes of campsites or “management areas.” A campsite impact matrix was developed to evaluate management areas based on total impacts (correlated to the total area of campsite development) and the density, or concentration, of impacts relative to each area's potentially campable area. The matrix is used to quantify potential recreational opportunities for wilderness visitors in a spectrum from areas offering low impact-dispersed camping to those areas offering high impact-concentrated camping. Wilderness managers can use this type of information to evaluate use distribution patterns, identify areas to increase or decrease use, and to identify areas needing site-specific regulations (e.g., one-night camping limits) to preserve wilderness resources and guarantee outstanding opportunities for solitude.
Method of making metal matrix composites reinforced with ceramic particulates
Cornie, James A.; Kattamis, Theodoulos; Chambers, Brent V.; Bond, Bruce E.; Varela, Raul H.
1989-01-01
Composite materials and methods for making such materials are disclosed in which dispersed ceramic particles are at chemical equilibrium with a base metal matrix, thereby permitting such materials to be remelted and subsequently cast or otherwise processed to form net weight parts and other finished (or semi-finished) articles while maintaining the microstructure and mechanical properties (e.g. wear resistance or hardness) of the original composite. The composite materials of the present invention are composed of ceramic particles in a base metal matrix. The ceramics are preferably carbides of titanium, zirconium, tungsten, molybdenum or other refractory metals. The base metal can be iron, nickel, cobalt, chromium or other high temperature metal and alloys thereof. For ferrous matrices, alloys suitable for use as the base metal include cast iron, carbon steels, stainless steels and iron-based superalloys.
Method of making metal matrix composites reinforced with ceramic particulates
Cornie, J.A.; Kattamis, T.; Chambers, B.V.; Bond, B.E.; Varela, R.H.
1989-08-01
Composite materials and methods for making such materials are disclosed in which dispersed ceramic particles are at chemical equilibrium with a base metal matrix, thereby permitting such materials to be remelted and subsequently cast or otherwise processed to form net weight parts and other finished (or semi-finished) articles while maintaining the microstructure and mechanical properties (e.g. wear resistance or hardness) of the original composite. The composite materials of the present invention are composed of ceramic particles in a base metal matrix. The ceramics are preferably carbides of titanium, zirconium, tungsten, molybdenum or other refractory metals. The base metal can be iron, nickel, cobalt, chromium or other high temperature metal and alloys thereof. For ferrous matrices, alloys suitable for use as the base metal include cast iron, carbon steels, stainless steels and iron-based superalloys. 2 figs.
Evaluating wilderness recreational opportunities: Application of an impact matrix
NASA Astrophysics Data System (ADS)
Stohlgren, Thomas J.; Parsons, David J.
1992-05-01
An inventory of the severity and spatial distribution of wilderness campsite impacts in Sequoia and Kings Canyon National Parks identified a total of 273 distinct nodes of campsites or “management areas.” A campsite impact matrix was developed to evaluate management areas based on total impacts (correlated to the total area of campsite development) and the density, or concentration, of impacts relative to each area's potentially campable area. The matrix is used to quantify potential recreational opportunities for wilderness visitors in a spectrum from areas offering low impact-dispersed camping to those areas offering high impact-concentrated camping. Wilderness managers can use this type of information to evaluate use distribution patterns, identify areas to increase or decrease use, and to identify areas needing site-specific regulations (e.g., one-night camping limits) to preserve wilderness resources and guarantee outstanding opportunities for solitude.
Calculation of transition matrix elements by nonsingular orbital transformations
NASA Astrophysics Data System (ADS)
Kývala, Mojmír
A general strategy is described for the evaluation of transition matrix elements between pairs of full class CI wave functions built up from mutually nonorthogonal molecular orbitals. A new method is proposed for the counter-transformation of the linear expansion coefficients of a full CI wave function under a nonsingular transformation of the molecular-orbital basis. The method, which consists in a straightforward application of the Cauchy-Binet formula to the definition of a Slater determinant, is shown to be simple and suitable for efficient implementation on current high-performance computers. The new method appears mainly beneficial to the calculation of miscellaneous transition matrix elements among individually optimized CASSCF states and to the re-evaluation of the CASCI expansion coefficients in Slater-determinant bases formed from arbitrarily rotated (e.g., localized or, conversely, delocalized) active molecular orbitals.
Conditional random matrix ensembles and the stability of dynamical systems
NASA Astrophysics Data System (ADS)
Kirk, Paul; Rolando, Delphine M. Y.; MacLean, Adam L.; Stumpf, Michael P. H.
2015-08-01
Random matrix theory (RMT) has found applications throughout physics and applied mathematics, in subject areas as diverse as communications networks, population dynamics, neuroscience, and models of the banking system. Many of these analyses exploit elegant analytical results, particularly the circular law and its extensions. In order to apply these results, assumptions must be made about the distribution of matrix elements. Here we demonstrate that the choice of matrix distribution is crucial. In particular, adopting an unrealistic matrix distribution for the sake of analytical tractability is liable to lead to misleading conclusions. We focus on the application of RMT to the long-standing, and at times fractious, ‘diversity-stability debate’, which is concerned with establishing whether large complex systems are likely to be stable. Early work (and subsequent elaborations) brought RMT to bear on the debate by modelling the entries of a system’s Jacobian matrix as independent and identically distributed (i.i.d.) random variables. These analyses were successful in yielding general results that were not tied to any specific system, but relied upon a restrictive i.i.d. assumption. Other studies took an opposing approach, seeking to elucidate general principles of stability through the analysis of specific systems. Here we develop a statistical framework that reconciles these two contrasting approaches. We use a range of illustrative dynamical systems examples to demonstrate that: (i) stability probability cannot be summarily deduced from any single property of the system (e.g. its diversity); and (ii) our assessment of stability depends on adequately capturing the details of the systems analysed. Failing to condition on the structure of dynamical systems will skew our analysis and can, even for very small systems, result in an unnecessarily pessimistic diagnosis of their stability.
Grape seed extracts inhibit dentin matrix degradation by MMP-3
Khaddam, Mayssam; Salmon, Benjamin; Le Denmat, Dominique; Tjaderhane, Leo; Menashi, Suzanne; Chaussain, Catherine; Rochefort, Gaël Y.; Boukpessi, Tchilalo
2014-01-01
Since Matrix metalloproteinases (MMPs) have been suggested to contribute to dentin caries progression, the hypothesis that MMP inhibition would affect the progression of dentin caries is clinically relevant. Grape seed extracts (GSE) have been previously reported to be natural inhibitors of MMPs. Objective: To evaluate the capacity of a GSE mouthrinse to prevent the degradation of demineralized dentin matrix by MMP-3 (stromelysin-1). Materials and Methods: Standardized blocks of dentin obtained from sound permanent teeth extracted for orthodontic reasons were demineralized with Ethylenediaminetetraacetic acid (EDTA) and pretreated either with (A) GSE (0.2% w/v), (B) amine fluoride (AmF) (20% w/v), (C) a mouthrinse which contains both, (D) placebo, (E) sodium fluoride (0.15 mg.ml−1), (F) PBS, (G) Chlorhexidine digluconate (CHX), or (H) zinc chloride (ZnCl2). The dentin blocks were then incubated with activated recombinant MMP-3. The supernatants were analyzed by Western Blot for several dentin matrix proteins known to be MMP-3 substrate. In parallel, scanning electron microscopy (SEM) was performed on resin replica of the dentin blocks. Results: Western blot analysis of the supernatants revealed that MMP-3 released from the dentin matrix small proteoglycans (decorin and biglycan) and dentin sialoprotein (DSP) in the AmF, sodium fluoride, PBS and placebo pretreated groups, but not in the GSE and mouthrinse pretreated groups. SEM examination of resin replica showed that the mouthrinse and its active components not only had an anti-MMP action but also modified the dentin surface accessibility. Conclusion: This study shows that GSE either alone or combined with AmF as in the evaluated mouthrinse limits dentin matrix degradation. This association may be promising to prevent the progression of caries within dentin. However, the procedure should be adapted to clinically relevant durations. PMID:25400590
Bibliography on Ceramic Matrix Composites and Reinforcing Whiskers, Platelets, and Fibers, 1970-1990
1993-08-01
Pigott, G. H. Shalek, P D. Hurley, G F Pinto , P. J. Christiansen, D. E. Parkinson, W J J. Mater. Sci. Lett. Katz, J. D. 7 (4), 350-352, 1988 Metal Matrix...of Silicon Carbide-Silicon Carbide Materials Edited by A. R. Bunsell, Abbe, Francois Chermant, Jean -Louis P. Lamicq and A. Massiah J. Am. Ceram. Soc...Babonneau, Florence Livage, Jacques Zirconium Diboride and Tantalum Carbide Soraru, Gian D. Carturan. G Carbon Composites Mackenzie, J. D. Starrett, H
Extracellular matrix proteins of dentine.
Butler, W T; Ritchie, H H; Bronckers, A L
1997-01-01
Bone and dentine extracellular matrix proteins are similar, consisting primarily of type I collagen, acidic proteins and proteoglycans. Although collagen forms the lattice for deposition of calcium and phosphate for formation of carbonate apatite, the non-collagenous proteins are believed to control initiation and growth of the crystals. Despite this similarity, dentine contains three unique proteins apparently absent from bone and other tissue: dentine phosphophoryn (DPP), dentine matrix protein 1 (DMP1) and dentine sialoprotein (DSP). DPP and DMP1 are acidic phosphoproteins probably involved in the control of mineralization processes. DPP may localize in gap regions of collagen and initiate apatite crystal formation by binding large quantities of calcium in a conformation that promotes this process. Extensive studies have been conducted in our laboratory on the nature, biosynthesis, localization and gene structure of DSP. Immunolocalization studies showed that rat DSP, a 53 kDa sialic acid-rich glycoprotein, was synthesized by young and mature odontoblasts, and by dental pulp cells and pre-ameloblasts, but not by ameloblasts, osteoblasts, chondrocytes or other cell types. The cDNA sequence indicated that DSP was a 366-residue protein with several potential N-glycosylation sites, as well as phosphorylation sites, but that the amino acid sequence was dissimilar to that of other known proteins. Northern blot analysis detected several mRNA species near 4.6 and 1.5 kb, indicative of alternative splicing events. Evidence for two DSP genes was obtained, further complicating this picture. Recent in situ hybridization studies utilizing rat and mouse molars and incisors indicated that DSP mRNA was expressed by young odontoblasts and odontoblasts in animals of all ages. Transcripts were also observed in pre-ameloblasts. The expression of DSP mRNA ceased when these cells matured to become secretory ameloblasts. DSP transcripts were not detected in osteoblasts or other cell
Klenow exo-, as opposed to exo+, traverses through G-G:C triplex by melting G-G base pairs.
Ramanathan, Sunita; Chary, Kandala V R; Rao, Basuthkar J
2002-07-19
G-G base-paired hairpin DNA structures on template strands offer potential "road-blocks" to a traversing polymerase. Klenow polymerase (exo+) pauses while replicating through G-G base-paired hairpin DNA due to the generation of G-G:C triplex. However, exonuclease-deficient Klenow traverses through de novo generated G-G:C triplexes leading to full-length C:G duplexes. Alleviation of such road-blocks by exo- Klenow ensues faster at lower Mg2+, a kinetic effect consistent with the role of Mg2+ in stabilizing G-G:C triplex fold. The ability of exonuclease-deficient polymerase to go past the de novo generated G-G:C triplexes suggests that the "idling" of exo+ polymerase at G-G road-block is due to the reiterative polymerase/exonuclease action. The full-length replication product carrying a C(n)-G(n) duplex at one end is further "expanded" by exo- Klenow through C-strand "slippage" leading to the generation of C+-G:C triplex, which is exemplified by the premature arrest of the same at low pH that further stabilizes the C+-G:C triplex. (c) 2002 Elsevier Science (USA).
Fragmentation of extracellular matrix by hypochlorous acid.
Woods, Alan A; Davies, Michael J
2003-01-01
The interaction of extracellular matrix with cells regulates their adhesion, migration and proliferation, and it is believed that damage to vascular matrix components is a factor in the development of atherosclerosis. Evidence has been provided for a role for the haem enzyme MPO (myeloperoxidase), released by activated monocytes (and possibly macrophages), in oxidative events within the artery wall. As MPO is released extracellularly, and is highly basic, it might be expected to associate with poly-anionic matrix components thereby localizing damage to these materials. In this study the reaction of the MPO-derived oxidant hypochlorous acid (HOCl) with extracellular matrix from vascular smooth muscle cells and healthy pig arteries has been examined. HOCl is rapidly consumed by such matrix samples, with the formation of matrix-derived chloramines or chloramides. The yield of these intermediates increases with HOCl dose. These materials undergo a time- and temperature-dependent decay, which parallels the release of sugar and protein components from the treated matrix, consistent with these species being important intermediates. Matrix damage is enhanced by species that increase chloramine/chloramide decomposition, with copper and iron ions being effective catalysts, and decreased by compounds which scavenge chloramines/chloramides, or species derived from them. The effect of such matrix modifications on cellular behaviour is poorly understood, though it is known that changes in matrix materials can have profound effects on cell adhesion, proliferation, growth and phenotype. The observed matrix modifications reported here may therefore modulate cellular behaviour in diseases such as atherosclerosis where MPO-derived oxidants are generated. PMID:12911330
NASA Astrophysics Data System (ADS)
Tian, Yuxi; Sheinin, Vladimir; Kulikova, Olga; Mamardashvili, Nugzar; Scheblykin, Ivan G.
2014-04-01
For single molecule spectroscopy (SMS), molecules under study are usually immobilized in a polymer matrix e.g. poly(methyl methacrylate). We show a very significant improvement of the conjugated polymer MEH-PPV photo-stability and decrease of the luminescence impurities concentration when the matrix is purified. We identify benzoyl peroxide (a common radical initiator) as a possible oxidizing agent which residuals in the polymer matrix destroy MEH-PPV. These results show that purification and selection of a matrix obtained by radical-free synthetic technique are of great importance for SMS as well as other technologies using polymer matrices as hosts for light-emitting materials.
Jabłońska-Trypuć, Agata; Matejczyk, Marzena; Rosochacki, Stanisław
2016-01-01
The main group of enzymes responsible for the collagen and other protein degradation in extracellular matrix (ECM) are matrix metalloproteinases (MMPs). Collagen is the main structural component of connective tissue and its degradation is a very important process in the development, morphogenesis, tissue remodeling, and repair. Typical structure of MMPs consists of several distinct domains. MMP family can be divided into six groups: collagenases, gelatinases, stromelysins, matrilysins, membrane-type MMPs, and other non-classified MMPs. MMPs and their inhibitors have multiple biological functions in all stages of cancer development: from initiation to outgrowth of clinically relevant metastases and likewise in apoptosis and angiogenesis. MMPs and their inhibitors are extensively examined as potential anticancer drugs. MMP inhibitors can be divided into two main groups: synthetic and natural inhibitors. Selected synthetic inhibitors are in clinical trials on humans, e.g. synthetic peptides, non-peptidic molecules, chemically modified tetracyclines, and bisphosphonates. Natural MMP inhibitors are mainly isoflavonoids and shark cartilage.
The evolution of extracellular matrix.
Ozbek, Suat; Balasubramanian, Prakash G; Chiquet-Ehrismann, Ruth; Tucker, Richard P; Adams, Josephine C
2010-12-01
We present a perspective on the molecular evolution of the extracellular matrix (ECM) in metazoa that draws on research publications and data from sequenced genomes and expressed sequence tag libraries. ECM components do not function in isolation, and the biological ECM system or "adhesome" also depends on posttranslational processing enzymes, cell surface receptors, and extracellular proteases. We focus principally on the adhesome of internal tissues and discuss its origins at the dawn of the metazoa and the expansion of complexity that occurred in the chordate lineage. The analyses demonstrate very high conservation of a core adhesome that apparently evolved in a major wave of innovation in conjunction with the origin of metazoa. Integrin, CD36, and certain domains predate the metazoa, and some ECM-related proteins are identified in choanoflagellates as predicted sequences. Modern deuterostomes and vertebrates have many novelties and elaborations of ECM as a result of domain shuffling, domain innovations and gene family expansions. Knowledge of the evolution of metazoan ECM is important for understanding how it is built as a system, its roles in normal tissues and disease processes, and has relevance for tissue engineering, the development of artificial organs, and the goals of synthetic biology.
Channeled partial Mueller matrix polarimetry
NASA Astrophysics Data System (ADS)
Alenin, Andrey S.; Tyo, J. S.
2015-09-01
In prior work,1,2 we introduced methods to treat channeled systems in a way that is similar to Data Reduction Method (DRM), by focusing attention on the Fourier content of the measurement conditions. Introduction of Q enabled us to more readily extract the performance of the system and thereby optimize it to obtain reconstruction with the least noise. The analysis tools developed for that exercise can be expanded to be applicable to partial Mueller Matrix Polarimeters (pMMPs), which were a topic of prior discussion as well. In this treatment, we combine the principles involved in both of those research trajectories and identify a set of channeled pMMP families. As a result, the measurement structure of such systems is completely known and the design of a channeled pMMP intended for any given task becomes a search over a finite set of possibilities, with the additional channel rotation allowing for a more desirable Mueller element mixing.
Advanced Integration Matrix Education Outreach
NASA Technical Reports Server (NTRS)
Paul Heather L.
2004-01-01
The Advanced Integration Matrix (AIM) will design a ground-based test facility for developing revolutionary integrated systems for joint human-robotic missions in order to study and solve systems-level integration issues for exploration missions beyond Low Earth Orbit (LEO). This paper describes development plans for educational outreach activities related to technological and operational integration scenarios similar to the challenges that will be encountered through this project. The education outreach activities will provide hands-on, interactive exercises to allow students of all levels to experience design and operational challenges similar to what NASA deals with everyday in performing the integration of complex missions. These experiences will relate to and impact students everyday lives by demonstrating how their interests in science and engineering can develop into future careers, and reinforcing the concepts of teamwork and conflict resolution. Allowing students to experience and contribute to real-world development, research, and scientific studies of ground-based simulations for complex exploration missions will stimulate interest in the space program, and bring NASA's challenges to the student level. By enhancing existing educational programs and developing innovative activities and presentations, AIM will support NASA s endeavor to "inspire the next generation of explorers.. .as only NASA can."
Advanced Integration Matrix Education Outreach
NASA Technical Reports Server (NTRS)
Paul Heather L.
2004-01-01
The Advanced Integration Matrix (AIM) will design a ground-based test facility for developing revolutionary integrated systems for joint human-robotic missions in order to study and solve systems-level integration issues for exploration missions beyond Low Earth Orbit (LEO). This paper describes development plans for educational outreach activities related to technological and operational integration scenarios similar to the challenges that will be encountered through this project. The education outreach activities will provide hands-on, interactive exercises to allow students of all levels to experience design and operational challenges similar to what NASA deals with everyday in performing the integration of complex missions. These experiences will relate to and impact students everyday lives by demonstrating how their interests in science and engineering can develop into future careers, and reinforcing the concepts of teamwork and conflict resolution. Allowing students to experience and contribute to real-world development, research, and scientific studies of ground-based simulations for complex exploration missions will stimulate interest in the space program, and bring NASA's challenges to the student level. By enhancing existing educational programs and developing innovative activities and presentations, AIM will support NASA s endeavor to "inspire the next generation of explorers.. .as only NASA can."
The Evolution of Extracellular Matrix
Özbek, Suat; Balasubramanian, Prakash G.; Chiquet-Ehrismann, Ruth; Tucker, Richard P.
2010-01-01
We present a perspective on the molecular evolution of the extracellular matrix (ECM) in metazoa that draws on research publications and data from sequenced genomes and expressed sequence tag libraries. ECM components do not function in isolation, and the biological ECM system or “adhesome” also depends on posttranslational processing enzymes, cell surface receptors, and extracellular proteases. We focus principally on the adhesome of internal tissues and discuss its origins at the dawn of the metazoa and the expansion of complexity that occurred in the chordate lineage. The analyses demonstrate very high conservation of a core adhesome that apparently evolved in a major wave of innovation in conjunction with the origin of metazoa. Integrin, CD36, and certain domains predate the metazoa, and some ECM-related proteins are identified in choanoflagellates as predicted sequences. Modern deuterostomes and vertebrates have many novelties and elaborations of ECM as a result of domain shuffling, domain innovations and gene family expansions. Knowledge of the evolution of metazoan ECM is important for understanding how it is built as a system, its roles in normal tissues and disease processes, and has relevance for tissue engineering, the development of artificial organs, and the goals of synthetic biology. PMID:21160071
Clinical implications of matrix metalloproteinases.
Mandal, Malay; Mandal, Amritlal; Das, Sudip; Chakraborti, Tapati; Sajal, Chakraborti
2003-10-01
Matrix metalloproteinases (MMPs) are a family of neutral proteinases that are important for normal development, wound healing, and a wide variety of pathological processes, including the spread of metastatic cancer cells, arthritic destruction of joints, atherosclerosis, pulmonary fibrosis, emphysema and neuroinflammation. In the central nervous system (CNS), MMPs have been shown to degrade components of the basal lamina, leading to disruption of the blood brain barrier and to contribute to the neuroinflammatory responses in many neurological diseases. Inhibition of MMPs have been shown to prevent progression of these diseases. Currently, certain MMP inhibitors have entered into clinical trials. A goal to the future should be to design selective synthetic inhibitors of MMPs that have minimum side effects. MMP inhibitors are designed in such a way that these can not only bind at the active site of the proteinases but also to have the characteristics to bind to other sites of MMPs which might be a promising route for therapy. To name a few: catechins, a component isolated from green tea; and Novastal, derived from extracts of shark cartilage are currently in clinical trials for the treatment of MMP-mediated diseases.
EA 18G Growler Aircraft (EA 18G)
2015-12-01
Assigned: July 16, 2015 Program Information Program Name EA-18G Growler Aircraft (EA-18G) DoD Component Navy Responsible Office References SAR...Baseline (Production Estimate) Defense Acquisition Executive (DAE) Approved Acquisition Program Baseline (APB) dated July 18, 2007 Approved APB Navy...UNCLASSIFIED 5 Mission and Description The EA-18G Growler Aircraft (EA-18G) is the fourth major variant of the F/A-18 family of aircraft. The EA-18G
Detwiler, Russell
2014-06-30
Matrix diffusion and adsorption within a rock matrix are widely regarded as important mechanisms for retarding the transport of radionuclides and other solutes in fractured rock (e.g., Neretnieks, 1980; Tang et al., 1981; Maloszewski and Zuber, 1985; Novakowski and Lapcevic, 1994; Jardine et al., 1999; Zhou and Xie, 2003; Reimus et al., 2003a,b). When remediation options are being evaluated for old sources of contamination, where a large fraction of contaminants reside within the rock matrix, slow diffusion out of the matrix greatly increases the difficulty and timeframe of remediation. Estimating the rates of solute exchange between fractures and the adjacent rock matrix is a critical factor in quantifying immobilization and/or remobilization of DOE-relevant contaminants within the subsurface. In principle, the most rigorous approach to modeling solute transport with fracture-matrix interaction would be based on local-scale coupled advection-diffusion/dispersion equations for the rock matrix and in discrete fractures that comprise the fracture network (Discrete Fracture Network and Matrix approach, hereinafter referred to as DFNM approach), fully resolving aperture variability in fractures and matrix property heterogeneity. However, such approaches are computationally demanding, and thus, many predictive models rely upon simplified models. These models typically idealize fracture rock masses as a single fracture or system of parallel fractures interacting with slabs of porous matrix or as a mobile-immobile or multi-rate mass transfer system. These idealizations provide tractable approaches for interpreting tracer tests and predicting contaminant mobility, but rely upon a fitted effective matrix diffusivity or mass-transfer coefficients. However, because these fitted parameters are based upon simplified conceptual models, their effectiveness at predicting long-term transport processes remains uncertain. Evidence of scale dependence of effective matrix diffusion
Attur, Mukundan; Yang, Qing; Shimada, Kohei; Tachida, Yuki; Nagase, Hiroyuki; Mignatti, Paolo; Statman, Lauren; Palmer, Glyn; Kirsch, Thorsten; Beier, Frank; Abramson, Steven B.
2015-01-01
We investigated the role of periostin, an extracellular matrix protein, in the pathophysiology of osteoarthritis (OA). In OA, dysregulated gene expression and phenotypic changes in articular chondrocytes culminate in progressive loss of cartilage from the joint surface. The molecular mechanisms underlying this process are poorly understood. We examined periostin expression by immunohistochemical analysis of lesional and nonlesional cartilage from human and rodent OA knee cartilage. In addition, we used small interfering (si)RNA and adenovirus transduction of chondrocytes to knock down and up-regulate periostin levels, respectively, and analyzed its effect on matrix metalloproteinase (MMP)-13, a disintegrin and MMP with thrombospondin motifs (ADAMTS)-4, and type II collagen expression. We found high periostin levels in human and rodent OA cartilage. Periostin increased MMP-13 expression dose [1–10 µg/ml (EC50 0.5–1 μg/ml)] and time (24–72 h) dependently, significantly enhanced expression of ADAMTS4 mRNA, and promoted cartilage degeneration through collagen and proteoglycan degradation. Periostin induction of MMP-13 expression was inhibited by CCT031374 hydrobromide, an inhibitor of the canonical Wnt/β-catenin signaling pathway. In addition, siRNA-mediated knockdown of endogenous periostin blocked constitutive MMP-13 expression. These findings implicate periostin as a catabolic protein that promotes cartilage degeneration in OA by up-regulating MMP-13 through canonical Wnt signaling.—Attur, M., Yang, Q., Shimada, K., Tachida, Y., Nagase, H., Mignatti, P., Statman, L., Palmer, G., Kirsch, T., Beier, F., Abramson, A. B. Elevated expression of periostin in human osteoarthritic cartilage and its potential role in matrix degradation via matrix metalloproteinase-13. PMID:26092928
Introduction to Matrix Sampling for the Practitioner.
ERIC Educational Resources Information Center
Sirotnik, Kenneth A.
One solution to the problem of obtaining test scores in order to assess multiple outcomes of educational programs is a basically simple technique called matrix sampling. Matrix sampling is the estimation of total test score statistics by administering random subsets of test items to randomly selected students. This chapter lays out the specific…
Multimedia Matrix: A Cognitive Strategy for Designers.
ERIC Educational Resources Information Center
Sherry, Annette C.
This instructional development project evaluates the effect of a matrix-based strategy to assist multimedia authors in acquiring and applying principles for effective multimedia design. The Multimedia Matrix, based on the Park and Hannafin "Twenty Principles and Implications for Interactive Multimedia" design, displays a condensed…
Finding nonoverlapping substructures of a sparse matrix
Pinar, Ali; Vassilevska, Virginia
2004-08-09
Many applications of scientific computing rely on computations on sparse matrices, thus the design of efficient implementations of sparse matrix kernels is crucial for the overall efficiency of these applications. Due to the high compute-to-memory ratio and irregular memory access patterns, the performance of sparse matrix kernels is often far away from the peak performance on a modern processor. Alternative data structures have been proposed, which split the original matrix A into A{sub d} and A{sub s}, so that A{sub d} contains all dense blocks of a specified size in the matrix, and A{sub s} contains the remaining entries. This enables the use of dense matrix kernels on the entries of A{sub d} producing better memory performance. In this work, we study the problem of finding a maximum number of non overlapping rectangular dense blocks in a sparse matrix, which has not been studied in the sparse matrix community. We show that the maximum non overlapping dense blocks problem is NP-complete by using a reduction from the maximum independent set problem on cubic planar graphs. We also propose a 2/3-approximation algorithm for 2 times 2 blocks that runs in linear time in the number of nonzeros in the matrix. We discuss alternatives to rectangular blocks such as diagonal blocks and cross blocks and present complexity analysis and approximation algorithms.
The Molecules of the Cell Matrix.
ERIC Educational Resources Information Center
Weber, Klaus; Osborn, Mary
1985-01-01
Cytoplasmic proteins form a highly structured yet changeable matrix that affects cell shape, division, motion, and transport of vesicles and organelles. Types of microfilaments, research techniques, actin and myosin, tumor cells, and other topics are addressed. Evidence indicates that the cell matrix might have a bearing on metabolism. (DH)
Matrix theory on non-orientable surfaces
NASA Astrophysics Data System (ADS)
Zwart, Gysbert
1998-06-01
We construct the Matrix theory descriptions of M-theory on the Möbius strip and the Klein bottle. In a limit, these provide the matrix string theories for the CHL string and an orbifold of type IIA string theory.
Reduction of the scattering matrix array
Sadovskyy, I. A.
2015-09-30
The scattering matrix approach is widely applied in wave engineering and quantum physics. Usually, a combination of multiple scattering matrices is used. In this article, we consider arbitrary arrays of interconnected scattering matrices and present a formal result for the reduced scattering matrix. We demonstrate this approach in two well-known scattering problems.
Matrix Management: An Organizational Alternative for Libraries.
ERIC Educational Resources Information Center
Johnson, Peggy
1990-01-01
Describes various organizational structures and models, presents matrix management as an alternative to traditional hierarchical structures, and suggests matrix management as an appropriate organizational alternative for academic libraries. Benefits that are discussed include increased flexibility, a higher level of professional independence, and…
A marketing matrix for health care organizations.
Weaver, F J; Gombeski, W R; Fay, G W; Eversman, J J; Cowan-Gascoigne, C
1986-06-01
Irrespective of the formal marketing structure successful marketing for health care organizations requires the input on many people. Detailed here is the Marketing Matrix used at the Cleveland Clinic Foundation in Cleveland, Ohio. This Matrix is both a philosophy and a tool for clarifying and focusing the organization's marketing activities.
The Molecules of the Cell Matrix.
ERIC Educational Resources Information Center
Weber, Klaus; Osborn, Mary
1985-01-01
Cytoplasmic proteins form a highly structured yet changeable matrix that affects cell shape, division, motion, and transport of vesicles and organelles. Types of microfilaments, research techniques, actin and myosin, tumor cells, and other topics are addressed. Evidence indicates that the cell matrix might have a bearing on metabolism. (DH)
Metal matrix composites microfracture: Computational simulation
NASA Technical Reports Server (NTRS)
Mital, Subodh K.; Caruso, John J.; Chamis, Christos C.
1990-01-01
Fiber/matrix fracture and fiber-matrix interface debonding in a metal matrix composite (MMC) are computationally simulated. These simulations are part of a research activity to develop computational methods for microfracture, microfracture propagation and fracture toughness of the metal matrix composites. The three-dimensional finite element model used in the simulation consists of a group of nine unidirectional fibers in three by three unit cell array of SiC/Ti15 metal matrix composite with a fiber volume ration of 0.35. This computational procedure is used to predict the fracture process and establish the hierarchy of fracture modes based on strain energy release rate. It is also used to predict stress redistribution to surrounding matrix-fibers due to initial and progressive fracture of fiber/matrix and due to debonding of fiber-matrix interface. Microfracture results for various loading cases such as longitudinal, transverse, shear and bending are presented and discussed. Step-by-step procedures are outlined to evaluate composite microfracture for a given composite system.
Metal matrix composites microfracture - Computational simulation
NASA Technical Reports Server (NTRS)
Mital, S. K.; Caruso, J. J.; Chamis, C. C.
1990-01-01
Fiber/matrix fracture and fiber-matrix interface debonding in a metal matrix composite (MMC) are computationally simulated. These simulations are part of a research activity to develop computational methods for microfracture, microfracture propagation and fracture toughness of the metal matrix composites. The three-dimensional finite element model used in the simulation consists of a group of nine unidirectional fibers in three by three unit cell array of SiC/Ti15 metal matrix composite with a fiber volume ration of 0.35. This computational procedure is used to predict the fracture process and establish the hierarchy of fracture modes based on strain energy release rate. It is also used to predict stress redistribution to surrounding matrix-fibers due to initial and progressive fracture of fiber/matrix and due to debonding of fiber-matrix interface. Microfracture results for various loading cases such as longitudinal, transverse, shear and bending are presented and discussed. Step-by-step procedures are outlined to evaluate composite microfracture for a given composite system.
Optimum interface properties for metal matrix composites
NASA Technical Reports Server (NTRS)
Ghosn, Louis J.; Lerch, Bradley A.
1989-01-01
Due to the thermal expansion coefficient mismatch (CTE) between the fiber and the matrix, high residual sresses exist in metal matrix composite systems upon cool down from processing temperature to room temperature. An interface material can be placed between the fiber and the matrix to reduce the high tensile residual stresses in the matrix. A computer program was written to minimize the residual stress in the matrix subject to the interface material properties. The decision variables are the interface modulus, thickness and thermal expansion coefficient. The properties of the interface material are optimized such that the average distortion energy in the matrix and the interface is minimized. As a result, the only active variable is the thermal expansion coefficient. The optimum modulus of the interface is always the minimum allowable value and the interface thickness is always the maximum allowable value, independent of the fiber/matrix system. The optimum interface thermal expansion coefficient is always between the values of the fiber and the matrix. Using this analysis, a survey of materials was conducted for use as fiber coatings in some specific composite systems.
Multipass matrix systems for diode laser spectroscope
NASA Astrophysics Data System (ADS)
Chernin, Semen M.
1996-02-01
Several modifications of multipass matrix systems (MMS) with a large relative aperture have been developed to be applied in diode laser spectroscopy. In these systems the images are formed on the field mirrors as compact rectangular matrices with a controlled amount of lines and columns. The number of passes may reach 600-1000 for mirrors with high-reflectivity layers (in three- and four-objective systems, respectively). In four-objective systems the error arising in the position of the previous odd image is compensated each time when images with even numbers are formed in the matrix. Moreover, four-objective systems provide the double superimposition of images in the matrix, resulting in a longer path length. Having a simple construction matrix systems ensure high optical and performance parameters. To improve performance characteristics of a matrix system operating under high vibration conditions (systems installed on aircraft or helicopter, etc.) a new promising variation of a four-objective matrix system was developed. Exit images of this modification are totally insensitive to vibrations. Matrix systems with a large angular aperture were developed for special applications with high resolution IR diode laser spectrometers. In view of their capacities, matrix systems are the new generation multipass systems.
An Independence Matrix for Visually Handicapped Learners.
ERIC Educational Resources Information Center
Corn, Anne L.
1985-01-01
A matrix organizes skills into a curriculum for independence and includes the following components: travel, reading, writing, speaking, recreation, and planning; and resources, problem solving, self-advocacy, and social skills. The use of the matrix in promoting the independence of a visually handicapped learner is described. (CL)
Matrix model description of baryonic deformations
Bena, Iosif; Murayama, Hitoshi; Roiban, Radu; Tatar, Radu
2003-03-13
We investigate supersymmetric QCD with N{sub c} + 1 flavors using an extension of the recently proposed relation between gauge theories and matrix models.The impressive agreement between the two sides provides a beautiful confirmation of the extension of the gauge theory-matrix model relation to this case.
Improvements in sparse matrix operations of NASTRAN
NASA Technical Reports Server (NTRS)
Harano, S.
1980-01-01
A "nontransmit" packing routine was added to NASTRAN to allow matrix data to be refered to directly from the input/output buffer. Use of the packing routine permits various routines for matrix handling to perform a direct reference to the input/output buffer if data addresses have once been received. The packing routine offers a buffer by buffer backspace feature for efficient backspacing in sequential access. Unlike a conventional backspacing that needs twice back record for a single read of one record (one column), this feature omits overlapping of READ operation and back record. It eliminates the necessity of writing, in decomposition of a symmetric matrix, of a portion of the matrix to its upper triangular matrix from the last to the first columns of the symmetric matrix, thus saving time for generating the upper triangular matrix. Only a lower triangular matrix must be written onto the secondary storage device, bringing 10 to 30% reduction in use of the disk space of the storage device.
Risk Management using Dependency Stucture Matrix
NASA Astrophysics Data System (ADS)
Petković, Ivan
2011-09-01
An efficient method based on dependency structure matrix (DSM) analysis is given for ranking risks in a complex system or process whose entities are mutually dependent. This rank is determined according to the element's values of the unique positive eigenvector which corresponds to the matrix spectral radius modeling the considered engineering system. For demonstration, the risk problem of NASA's robotic spacecraft is analyzed.
Block Hadamard measurement matrix with arbitrary dimension in compressed sensing
NASA Astrophysics Data System (ADS)
Liu, Shaoqiang; Yan, Xiaoyan; Fan, Xiaoping; Li, Fei; Xu, Wen
2017-01-01
As Hadamard measurement matrix cannot be used for compressing signals with dimension of a non-integral power-of-2, this paper proposes a construction method of block Hadamard measurement matrix with arbitrary dimension. According to the dimension N of signals to be measured, firstly, construct a set of Hadamard sub matrixes with different dimensions and make the sum of these dimensions equals to N. Then, arrange the Hadamard sub matrixes in a certain order to form a block diagonal matrix. Finally, take the former M rows of the block diagonal matrix as the measurement matrix. The proposed measurement matrix which retains the orthogonality of Hadamard matrix and sparsity of block diagonal matrix has highly sparse structure, simple hardware implements and general applicability. Simulation results show that the performance of our measurement matrix is better than Gaussian matrix, Logistic chaotic matrix, and Toeplitz matrix.
G-DYN Multibody Dynamics Engine
NASA Technical Reports Server (NTRS)
Acikmese, Behcet; Blackmore, James C.; Broderick, Daniel
2011-01-01
G-DYN is a multi-body dynamic simulation software engine that automatically assembles and integrates equations of motion for arbitrarily connected multibody dynamic systems. The algorithm behind G-DYN is based on a primal-dual formulation of the dynamics that captures the position and velocity vectors (primal variables) of each body and the interaction forces (dual variables) between bodies, which are particularly useful for control and estimation analysis and synthesis. It also takes full advantage of the spare matrix structure resulting from the system dynamics to numerically integrate the equations of motion efficiently. Furthermore, the dynamic model for each body can easily be replaced without re-deriving the overall equations of motion, and the assembly of the equations of motion is done automatically. G-DYN proved an essential software tool in the simulation of spacecraft systems used for small celestial body surface sampling, specifically in simulating touch-and-go (TAG) maneuvers of a robotic sampling system from a comet and asteroid. It is used extensively in validating mission concepts for small body sample return, such as Comet Odyssey and Galahad New Frontiers proposals.
Bashur, Chris A.; Venkataraman, Lavanya
2012-01-01
Cardiovascular tissues exhibit architecturally complex extracellular matrices, of which the elastic matrix forms a major component. The elastic matrix critically maintains native structural configurations of vascular tissues, determines their ability to recoil after stretch, and regulates cell signaling pathways involved in morphogenesis, injury response, and inflammation via biomechanical transduction. The ability to tissue engineer vascular replacements that incorporate elastic matrix superstructures unique to cardiac and vascular tissues is thus important to maintaining vascular homeostasis. However, the vascular elastic matrix is particularly difficult to tissue engineer due to the inherently poor ability of adult vascular cells to synthesize elastin precursors and organize them into mature structures in a manner that replicates the biocomplexity of elastic matrix assembly during development. This review discusses current tissue engineering materials (e.g., growth factors and scaffolds) and methods (e.g., dynamic stretch and contact guidance) used to promote cellular synthesis and assembly of elastic matrix superstructures, and the limitations of these approaches when applied to smooth muscle cells, the primary elastin-generating cell type in vascular tissues. The potential application of these methods for in situ regeneration of disrupted elastic matrix at sites of proteolytic vascular disease (e.g., abdominal aortic aneurysms) is also discussed. Finally, the review describes the potential utility of alternative cell types to elastic tissue engineering and regenerative matrix repair. Future progress in the field is contingent on developing a thorough understanding of developmental elastogenesis and then mimicking the spatiotemporal changes in the cellular microenvironment that occur during that phase. This will enable us to tissue engineer clinically applicable elastic vascular tissue replacements and to develop elastogenic therapies to restore homeostasis in
Nuclear Matrix Proteins in Human Colon Cancer
NASA Astrophysics Data System (ADS)
Keesee, Susan K.; Meneghini, Marc D.; Szaro, Robert P.; Wu, Ying-Jye
1994-03-01
The nuclear matrix is the nonchromatin scaffolding of the nucleus. This structure confers nuclear shape, organizes chromatin, and appears to contain important regulatory proteins. Tissue specific nuclear matrix proteins have been found in the rat, mouse, and human. In this study we compared high-resolution two-dimensional gel electropherograms of nuclear matrix protein patterns found in human colon tumors with those from normal colon epithelia. Tumors were obtained from 18 patients undergoing partial colectomy for adenocarcinoma of the colon and compared with tissue from 10 normal colons. We have identified at least six proteins which were present in 18 of 18 colon tumors and 0 of 10 normal tissues, as well as four proteins present in 0 of 18 tumors and in 10 of 10 normal tissues. These data, which corroborate similar findings of cancer-specific nuclear matrix proteins in prostate and breast, suggest that nuclear matrix proteins may serve as important markers for at least some types of cancer.
Universal portfolios generated by Vandermonde generating matrix
NASA Astrophysics Data System (ADS)
Tan, Choon Peng; Yong, Say Loong
2017-04-01
A universal portfolio generated by the one-parameter symmetric positive definite Vandermonde matrix is studied. It is obtained by maximizing the scaled growth rate of the estimated daily wealth return and minimizing the Mahalanobis squared divergence of two portfolio vectors associated with the Vandermonde matrix. The parameter of the Vandermonde matrix is chosen so that the matrix is positive definite. The companion matrices of the three and five-dimensional generating matrices are evaluated to determine the portfolios. Three and five stock-data sets are selected from the local stock exchange in Malaysia and the empirical performance of the portfolios is presented. There is empirical evidence that the use of an appropriate generating Vandermonde matrix may increase the wealth of investors.
The matrix exponential in transient structural analysis
NASA Technical Reports Server (NTRS)
Minnetyan, Levon
1987-01-01
The primary usefulness of the presented theory is in the ability to represent the effects of high frequency linear response with accuracy, without requiring very small time steps in the analysis of dynamic response. The matrix exponential contains a series approximation to the dynamic model. However, unlike the usual analysis procedure which truncates the high frequency response, the approximation in the exponential matrix solution is in the time domain. By truncating the series solution to the matrix exponential short, the solution is made inaccurate after a certain time. Yet, up to that time the solution is extremely accurate, including all high frequency effects. By taking finite time increments, the exponential matrix solution can compute the response very accurately. Use of the exponential matrix in structural dynamics is demonstrated by simulating the free vibration response of multi degree of freedom models of cantilever beams.
Fiber-matrix interfaces in ceramic composites
Besmann, T.M.; Stinton, D.P.; Kupp, E.R.; Shanmugham, S.; Liaw, P.K.
1996-12-31
The mechanical properties of ceramic matrix composites (CMCs) are governed by the relationships between the matrix, the interface material, and the fibers. In non-oxide matrix systems compliant pyrolytic carbon and BN have been demonstrated to be effective interface materials, allowing for absorption of mismatch stresses between fiber and matrix and offering a poorly bonded interface for crack deflection. The resulting materials have demonstrated remarkable strain/damage tolerance together with high strength. Carbon or BN, however, suffer from oxidative loss in many service environments, and thus there is a major search for oxidation resistant alternatives. This paper reviews the issues related to developing a stable and effective interface material for non-oxide matrix CMCs.
Biocompatible 3D Matrix with Antimicrobial Properties.
Ion, Alberto; Andronescu, Ecaterina; Rădulescu, Dragoș; Rădulescu, Marius; Iordache, Florin; Vasile, Bogdan Ștefan; Surdu, Adrian Vasile; Albu, Madalina Georgiana; Maniu, Horia; Chifiriuc, Mariana Carmen; Grumezescu, Alexandru Mihai; Holban, Alina Maria
2016-01-20
The aim of this study was to develop, characterize and assess the biological activity of a new regenerative 3D matrix with antimicrobial properties, based on collagen (COLL), hydroxyapatite (HAp), β-cyclodextrin (β-CD) and usnic acid (UA). The prepared 3D matrix was characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Microscopy (FT-IRM), Transmission Electron Microscopy (TEM), and X-ray Diffraction (XRD). In vitro qualitative and quantitative analyses performed on cultured diploid cells demonstrated that the 3D matrix is biocompatible, allowing the normal development and growth of MG-63 osteoblast-like cells and exhibited an antimicrobial effect, especially on the Staphylococcus aureus strain, explained by the particular higher inhibitory activity of usnic acid (UA) against Gram positive bacterial strains. Our data strongly recommend the obtained 3D matrix to be used as a successful alternative for the fabrication of three dimensional (3D) anti-infective regeneration matrix for bone tissue engineering.
Graphical evaluation of relativistic matrix elements
NASA Technical Reports Server (NTRS)
Huang, K. N.
1978-01-01
A graphical representation of angular momentum was used to evaluate relativistic matrix elements between antisymmetrized states of many particle configurations having any number of open shells. The antisymmetrized matrix element was expanded as a sum of semisymmetrized matrix elements. The diagram representing a semisymmetrized matrix element was composed of four diagram blocks; the bra block, the ket block, the spectator block, and the interaction block. The first three blocks indicate the couplings of the two interacting configurations while the last depends on the interaction and is the replaceable component. Interaction blocks for relativistic operators and commonly used potentials were summarized in ready to use forms. A simple step by step procedure was prescribed generally for calculating antisymmetrized matrix elements of one and two particle operators.
[Penile augmentation using acellular dermal matrix].
Zhang, Jin-ming; Cui, Yong-yan; Pan, Shu-juan; Liang, Wei-qiang; Chen, Xiao-xuan
2004-11-01
Penile enhancement was performed using acellular dermal matrix. Multiple layers of acellular dermal matrix were placed underneath the penile skin to enlarge its girth. Since March 2002, penile augmentation has been performed on 12 cases using acellular dermal matrix. Postoperatively all the patients had a 1.3-3.1 cm (2.6 cm in average) increase in penile girth in a flaccid state. The penis had normal appearance and feeling without contour deformities. All patients gained sexual ability 3 months after the operation. One had a delayed wound healing due to tight dressing, which was repaired with a scrotal skin flap. Penile enlargement by implantation of multiple layers of acellular dermal matrix was a safe and effective operation. This method can be performed in an outpatient ambulatory setting. The advantages of the acellular dermal matrix over the autogenous dermal fat grafts are elimination of donor site injury and scar and significant shortening of operation time.
NASA Technical Reports Server (NTRS)
1998-01-01
Richard G. (Dick) Ewers became a pilot in the Flight Crew Branch of NASA's Dryden Flight Research Center, Edwards, California, in May 1998. His flying duties focus on operation of the Airborne Science DC-8 and Systems Research F/A-18 aircraft, but he also maintains qualifications in the King Air and T-34C. He has more than 32 years and nearly 9,000 hours of military and civilian flight experience in all types of aircraft from jet fighters to blimps. Ewers came to NASA Dryden from a position as an engineering test pilot with Northrop Grumman's Electronic Sensors and Systems Division (formerly Westinghouse's Electronic Systems Group). He spent eight and a half years with Westinghouse flight testing radar and forward looking infrared systems under development for military and civilian use. Before going to work for Westinghouse, Ewers served for more than 21 years as a U.S. Marine Corps fighter and test pilot, flying F-4, A-4, and F/A-18 aircraft. He underwent flight training at Naval Air Station Pensacola, Fla., in 1969-70. He was subsequently assigned to both fighter/attack and reconnaissance squadrons before ultimately commanding an F-4S squadron for two years. Additionally, his flying included combat service in Vietnam and operational exchange tours with both U.S. Navy and U.S. Air Force squadrons flying F-4s around the world, including off aircraft carriers. Ewers graduated from the U.S. Naval Test Pilot School in 1981 and subsequently served two tours as a test pilot at the Naval Air Test Center, Patuxent River, Md. Most of his flight test experience was with the F/A-18 Hornet. He retired from the Marine Corps in 1989 with the rank of lieutenant colonel. Ewers graduated from the U.S. Air Force Academy in 1968 with a bachelor of science degree in engineering mechanics. He earned a master of science degree in aeronautical systems from the University of West Florida in 1970.
1998-12-02
Richard G. (Dick) Ewers became a pilot in the Flight Crew Branch of NASA's Dryden Flight Research Center, Edwards, California, in May 1998. His flying duties focus on operation of the Airborne Science DC-8 and Systems Research F/A-18 aircraft, but he also maintains qualifications in the King Air and T-34C. He has more than 32 years and nearly 9,000 hours of military and civilian flight experience in all types of aircraft from jet fighters to blimps. Ewers came to NASA Dryden from a position as an engineering test pilot with Northrop Grumman's Electronic Sensors and Systems Division (formerly Westinghouse's Electronic Systems Group). He spent eight and a half years with Westinghouse flight testing radar and forward looking infrared systems under development for military and civilian use. Before going to work for Westinghouse, Ewers served for more than 21 years as a U.S. Marine Corps fighter and test pilot, flying F-4, A-4, and F/A-18 aircraft. He underwent flight training at Naval Air Station Pensacola, Fla., in 1969-70. He was subsequently assigned to both fighter/attack and reconnaissance squadrons before ultimately commanding an F-4S squadron for two years. Additionally, his flying included combat service in Vietnam and operational exchange tours with both U.S. Navy and U.S. Air Force squadrons flying F-4s around the world, including off aircraft carriers. Ewers graduated from the U.S. Naval Test Pilot School in 1981 and subsequently served two tours as a test pilot at the Naval Air Test Center, Patuxent River, Md. Most of his flight test experience was with the F/A-18 Hornet. He retired from the Marine Corps in 1989 with the rank of lieutenant colonel. Ewers graduated from the U.S. Air Force Academy in 1968 with a bachelor of science degree in engineering mechanics. He earned a master of science degree in aeronautical systems from the University of West Florida in 1970.
NASA Technical Reports Server (NTRS)
1998-01-01
Richard G. (Dick) Ewers became a pilot in the Flight Crew Branch of NASA's Dryden Flight Research Center, Edwards, California, in May 1998. His flying duties focus on operation of the Airborne Science DC-8 and Systems Research F/A-18 aircraft, but he also maintains qualifications in the King Air and T-34C. He has more than 32 years and nearly 9,000 hours of military and civilian flight experience in all types of aircraft from jet fighters to blimps. Ewers came to NASA Dryden from a position as an engineering test pilot with Northrop Grumman's Electronic Sensors and Systems Division (formerly Westinghouse's Electronic Systems Group). He spent eight and a half years with Westinghouse flight testing radar and forward looking infrared systems under development for military and civilian use. Before going to work for Westinghouse, Ewers served for more than 21 years as a U.S. Marine Corps fighter and test pilot, flying F-4, A-4, and F/A-18 aircraft. He underwent flight training at Naval Air Station Pensacola, Fla., in 1969-70. He was subsequently assigned to both fighter/attack and reconnaissance squadrons before ultimately commanding an F-4S squadron for two years. Additionally, his flying included combat service in Vietnam and operational exchange tours with both U.S. Navy and U.S. Air Force squadrons flying F-4s around the world, including off aircraft carriers. Ewers graduated from the U.S. Naval Test Pilot School in 1981 and subsequently served two tours as a test pilot at the Naval Air Test Center, Patuxent River, Md. Most of his flight test experience was with the F/A-18 Hornet. He retired from the Marine Corps in 1989 with the rank of lieutenant colonel. Ewers graduated from the U.S. Air Force Academy in 1968 with a bachelor of science degree in engineering mechanics. He earned a master of science degree in aeronautical systems from the University of West Florida in 1970.
Google matrix analysis of the multiproduct world trade network
NASA Astrophysics Data System (ADS)
Ermann, Leonardo; Shepelyansky, Dima L.
2015-04-01
Using the United Nations COMTRADE database [United Nations Commodity Trade Statistics Database, available at: http://comtrade.un.org/db/. Accessed November (2014)] we construct the Google matrix G of multiproduct world trade between the UN countries and analyze the properties of trade flows on this network for years 1962-2010. This construction, based on Markov chains, treats all countries on equal democratic grounds independently of their richness and at the same time it considers the contributions of trade products proportionally to their trade volume. We consider the trade with 61 products for up to 227 countries. The obtained results show that the trade contribution of products is asymmetric: some of them are export oriented while others are import oriented even if the ranking by their trade volume is symmetric in respect to export and import after averaging over all world countries. The construction of the Google matrix allows to investigate the sensitivity of trade balance in respect to price variations of products, e.g. petroleum and gas, taking into account the world connectivity of trade links. The trade balance based on PageRank and CheiRank probabilities highlights the leading role of China and other BRICS countries in the world trade in recent years. We also show that the eigenstates of G with large eigenvalues select specific trade communities.
MATRIX City: A Multi-Risk Platform
NASA Astrophysics Data System (ADS)
Euchner, F.; Mignan, A.
2012-04-01
MATRIX City (the MATRIX Common IT sYstem) is the computational platform that is being developed in the course of the New Multi-Hazard and Multi-Risk Assessment Methods for Europe (MATRIX) project. MATRIX aims to develop multi-type hazard and risk assessment and mitigation tools suited to the European context. The core of MATRIX City is a risk engine of a novel type that is based on a sequential simulation approach, which allows to quantify interactions and other time-dependent processes at the hazard, exposure, vulnerability and risk levels. For risk estimation in realistic scenarios, data availability is crucial. To overcome this limitation, MATRIX City provides a component called Virtual City. It is a collection of heuristic databases, which provides a generic approach to quantifying multi-type hazard and risk when data coverage is poor, and for sensitivity analysis. MATRIX City results are intended to provide a "big picture" of the expected impact of multi-type hazard and risk modelling (as opposed to static modelling), thus being a valuable tool for decision support. MATRIX City development uses a modern software engineering approach (test-driven development, continuous integration). The architecture is flexible, so that new perils, new models and large datasets can be accommodated easily. However, it should be noted that hazard computation is not part of MATRIX City. Hazard footprints have to be provided as input data, as well as exposure and vulnerability. The data model used in MATRIX City is an enhancement of the Natural hazards' Risk Markup Language (NRML). An XML serialization of this data model, which is a GML (Geographic Markup Language) application schema, is used for data interchange.
Sol/Gel Processing Techniques for Glass Matrix Composites.
1987-11-01
development of a general technique (i.e., Pyrex is less susceptible to devitrification than SiO2 or TiO2 -SiO 2 ). In addition. the properties of these sol / gel ...of a sol / gel process for SIC 2 and SiO2 - TiO2 - together with a data base for their densification - are prerequisite to the successful fabrication of...S~%ad~ 5~ ~ ~ *~~~~;:>;::L-; 1: ’*~~’~ ’S. AFWL-TN-86-59 AFWL-TN- 86-59 00 SOL / GEL PROCESSING TECHNIQUES FOR GLASS MATRIX COMPOSITES 0) C. G
Pseudoscalar glueball mass from η-η'-G mixing
NASA Astrophysics Data System (ADS)
Cheng, Hai-Yang; Li, Hsiang-Nan; Liu, Keh-Fei
2009-01-01
We deduce the mass of the pseudoscalar glueball G from an η-η'-G mixing formalism based on the anomalous Ward identity for transition matrix elements. With the inputs from the recent KLOE experiment, we find a solution for the pseudoscalar glueball mass around (1.4±0.1)GeV, which is fairly insensitive to a range of inputs with or without Okubo-Zweig-Iizuka-rule violating effects. This affirms that η(1405), having a large production rate in the radiative J/Ψ decay and not seen in γγ reactions, is indeed a leading candidate for the pseudoscalar glueball. Other relevant quantities including the anomaly and pseudoscalar density matrix elements are obtained. The decay widths for G→γγ, ℓ+ℓ- are also predicted.
Hierarchical cluster analysis of matrix effects on 110 pesticide residues in 28 tea matrixes.
Li, Yan; Pang, Guo-Fang; Fan, Chun-Lin; Chen, Xi
2013-01-01
Matrix effects on 110 pesticides in 28 tea matrixes of different varieties and origins by LC/MS/MS were studied, and most of the pesticides exhibited soft and medium signal suppression. To better understand the influence of the tea varieties and the physicochemical characteristics of pesticides on the matrix effects, the multivariate analysis tool called hierarchical cluster analysis was applied. Tea matrixes were grouped into three clusters: unfermented, fermented, and post-fermented teas. Any type of tea can be chosen from each cluster as a corresponding representative matrix within that cluster to make matrix-matched solutions, which could simplify analysis while guaranteeing its accuracy. Matrix effects on most pesticides were similar despite the physicochemical diversities of the pesticides.
Conjunctival matrix metalloproteinases and their inhibitors in glaucoma patients.
Helin-Toiviainen, Minna; Rönkkö, Seppo; Puustjärvi, Tuomo; Rekonen, Petri; Ollikainen, Minna; Uusitalo, Hannu
2015-03-01
Chronic conjunctival inflammation, caused by various reasons, for example long-term use of topical drugs and/or their preservatives, affects the outcome of glaucoma surgery by interfering with wound healing. Matrix metalloproteinases (MMPs) remodel extracellular matrix (ECM) and are involved in the wound healing process. This study was designed to evaluate the conjunctival expression of MMPs and their tissue inhibitors (TIMPs) in the normal eye, primary open-angle glaucoma (POAG) and exfoliation glaucoma (ExG) and whether there is an association between staining intensities and deep sclerectomy outcome. Immunohistochemical procedures were performed on conjunctival samples which were obtained from POAG (n=11) and ExG (n=14) patients as well as normal (n=7) subjects. Antibodies against MMPs (MMP-1, -2, -3 and -9) and TIMPs (TIMP-1, -2 and -3) were used. In conjunctival stroma, expression levels of MMP-2 (p=0.047), MMP-3 (p=0.009), MMP-9 (p<0.001), TIMP-1 (p=0.003), TIMP-2 (p<0.001) and TIMP-3 (p<0.001) in ExG and MMP-9 (p=0.008), TIMP-2 (p=0.02) and TIMP-3 (p=0.002) in POAG were significantly increased compared to control. We further found correlations between expression of MMP-1 and MMP-3 and the length of pilocarpine treatment. The expression of MMPs and TIMPs is increased in the conjunctiva of POAG and ExG patients having a long history of topical antiglaucoma drops. Antiglaucoma agents and/or their preservatives alter the remodelling balance of ECM in conjunctiva of POAG and ExG eyes. The balance between MMPs and TIMPs may play a crucial role in the conjunctival wound healing process and the outcome of glaucoma surgery. © 2014 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.
2-Adic clustering of the PAM matrix.
Khrennikov, A Yu; Kozyrev, S V
2009-12-07
In this paper we demonstrate that the use of the system of 2-adic numbers provides a new insight to some problems of genetics, in particular, degeneracy of the genetic code and the structure of the PAM matrix in bioinformatics. The 2-adic distance is an ultrametric and applications of ultrametric in bioinformatics are not surprising. However, by using the 2-adic numbers we match ultrametric with a number theoretic structure. In this way we find new applications of an ultrametric which differ from known up to now in bioinformatics. We obtain the following results. We show that the PAM matrix A allows the expansion into the sum of the two matrices A=A((2))+A((infinity)), where the matrix A((2)) is 2-adically regular (i.e. matrix elements of this matrix are close to locally constant with respect to the discussed earlier by the authors 2-adic parametrization of the genetic code), and the matrix A((infinity)) is sparse. We discuss the structure of the matrix A((infinity)) in relation to the side chain properties of the corresponding amino acids. We introduce the family of substitution matrices A(alpha,beta)=alpha A((2))+beta A((infinity)), alpha,beta>or=0 which should allow to vary the alignment procedure in order to take into account the different chemical and geometric properties of the amino acids.
Linear and nonlinear projective nonnegative matrix factorization.
Yang, Zhirong; Oja, Erkki
2010-05-01
A variant of nonnegative matrix factorization (NMF) which was proposed earlier is analyzed here. It is called projective nonnegative matrix factorization (PNMF). The new method approximately factorizes a projection matrix, minimizing the reconstruction error, into a positive low-rank matrix and its transpose. The dissimilarity between the original data matrix and its approximation can be measured by the Frobenius matrix norm or the modified Kullback-Leibler divergence. Both measures are minimized by multiplicative update rules, whose convergence is proven for the first time. Enforcing orthonormality to the basic objective is shown to lead to an even more efficient update rule, which is also readily extended to nonlinear cases. The formulation of the PNMF objective is shown to be connected to a variety of existing NMF methods and clustering approaches. In addition, the derivation using Lagrangian multipliers reveals the relation between reconstruction and sparseness. For kernel principal component analysis (PCA) with the binary constraint, useful in graph partitioning problems, the nonlinear kernel PNMF provides a good approximation which outperforms an existing discretization approach. Empirical study on three real-world databases shows that PNMF can achieve the best or close to the best in clustering. The proposed algorithm runs more efficiently than the compared NMF methods, especially for high-dimensional data. Moreover, contrary to the basic NMF, the trained projection matrix can be readily used for newly coming samples and demonstrates good generalization.
Chondrule rims and interchondrule matrix in UOC
NASA Technical Reports Server (NTRS)
Alexander, C.; Hutchison, R.; Barber, D. J.
1984-01-01
Opaque rims around chondrules and clasts were distinguished from opaque, interchondrule matrix apparently unrelated spatially to chondrules and clasts. Microprobe and electron microscope techniques were used. The mean chemical composition for dark rim and matrix in Bishunpur and Tieschitz are similar to the opaque matrix of Huss, et al. However, the mean dark rim compositions in Bishunpur have significantly higher Fe, and lower Na, K, Al and Si than opaque interchondrule matrix. The opaque matrix of Huss, et al, essentially lies between these compositions. In Tieschitz only rim material was observed. In Tieschitz the rims are Si-poor and dominated by normative olivine (Fo50). Again there is an Na, K, Al component but is often nepheline normative rather than albitic. It too is probably present as glass, Ashworth (pers.comm.). In Bishunpur rims as well as the silicate-FeS, FeNi layering described by Allen, et al, discontinuous layering was observed within the silicate portion. This is apparently due to variations in the proportions of the components, particularly in the glassy phase. In Bishunpur there is a strong genetic link between matrix and rims, although rims seem to have formed under different, possibly more oxidizing, conditions. Also the presence of the same component in rims, matrix chondrules, and clasts suggests a common source.
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
[Modern polymers in matrix tablets technology].
Zimmer, Łukasz; Kasperek, Regina; Poleszak, Ewa
2014-01-01
Matrix tablets are the most popular method of oral drug administration, and polymeric materials have been used broadly in matrix formulations to modify and modulate drug release rate. The main goal of the system is to extend drug release profiles to maintain a constant in vivo plasma drug concentration and a consistent pharmacological effect. Polymeric matrix tablets offer a great potential as oral controlled drug delivery systems. Cellulose derivatives, like hydroxypropyl methylcellulose (HPMC) are often used as matrix formers. However, also other types of polymers can be used for this purpose including: Kollidon SR, acrylic acid polymers such as Eudragits and Carbopols. Nevertheless, polymers of natural origin like: carragens, chitosan and alginates widely used in the food and cosmetics industry are now coming to the fore of pharmaceutical research and are used in matrix tablets technology. Modern polymers allow to obtain matrix tablets by 3D printing, which enables to develop new formulation types. In this paper, the polymers used in matrix tablets technology and examples of their applications were described.
Fabric analysis of Allende matrix using EBSD
NASA Astrophysics Data System (ADS)
Watt, Lauren E.; Bland, Phil A.; Prior, Dave J.; Russell, Sara S.
Fabric analysis of the interstitial matrix material in primitive meteorites offers a novel window on asteroid formation and evolution. Electron backscatter diffraction (EBSD) has allowed fabrics in these fine-grained materials to be visualized in detail for the first time. Our data reveal that Allende, a CV3 chondrite, possesses a uniform, planar, short-axis alignment fabric that is pervasive on a broad scale and is probably the result of deformational shortening related to impact or gravitational compaction. Interference between this matrix fabric and the larger, more rigid components, such as dark inclusions (DIs) and calcium-aluminium-rich inclusions (CAIs), has lead to the development of locally oriented and intensified matrix fabrics. In addition, DIs possess fabrics that are conformable with the broader matrix fabric. These results suggest that DIs were in situ prior to the deformational shortening event responsible for these fabrics, thus providing an argument against dark inclusions being fragments from another lithified part of the asteroid (Kojima and Tomeoka 1996; Fruland et al. 1978). Moreover, both DIs and Allende matrix are highly porous (˜25%) (Corrigan et al. 1997). Mobilizing a highly porous DI during impact-induced brecciation without imposing a fabric and incorporating it into a highly porous matrix without significantly compacting these materials is improbable. We favor a model that involves Allende DIs, CAIs, and matrix accreting together and experiencing the same deformation events.
Modal acoustic emission source determination in silicon carbide matrix composites
NASA Astrophysics Data System (ADS)
Morscher, G. N.
2000-05-01
Modal acoustic emission has been used to monitor damage accumulation in woven silicon carbide (SiC) fiber reinforced SiC matrix composites during tensile testing. There are several potential sources of damage in these systems including transverse matrix cracking, fiber/matrix interphase debonding and sliding, longitudinal cracks in between plies, and fiber breakage. In the past, it has been shown that modal AE is excellent at detecting when damage occurs and subsides, where the damage occurs along the length of the sample, and the loss in material stiffness as a consequence of damage accumulation. The next step is to determine the extent that modal AE can be used to identify specific physical sources. This study will discuss the status of this aim for this composite system. Individual events were analyzed and correlated to specific sources based on the characteristics of the received waveforms, e.g., frequency spectrum and energy, and when the event occurred during the stress-history of the tensile test. Post-test microstructural examination of the test specimens enabled some correlation between specific types of AE events and damage sources.
Matrix isolation infrared spectra and photochemistry of hydantoin.
Ildiz, Gulce Ogruc; Nunes, Cláudio M; Fausto, Rui
2013-01-31
Hydantoin (C(3)H(4)N(2)O(2), 2,4-imidazolidinedione) was isolated in argon matrix at 10 K and its infrared spectrum and unimolecular photochemistry were investigated. The molecular structure of the compound was studied both at the DFT(B3LYP) and MP2 levels of approximation with valence triple- and quadruple-ζ basis sets (6-311++G(d,p); cc-pVQZ). It was concluded that the minima in the potential energy surfaces of the molecule correspond to C(1) symmetry structures. However, the energy barrier separating the two-equivalent-by-symmetry minima stays below their zero-point energy, which makes the C(s) symmetry structure, which separates the two minima, the experimentally relevant one. The electronic structure of the molecule was studied in detail by performing the Natural Bond Orbital analysis of its electronic configuration within the DFT(B3LYP)/cc-pVQZ space. The infrared spectrum of the matrix isolated compound was fully assigned also with help of the theoretically predicted spectrum. Upon irradiation at λ = 230 nm, matrix-isolated hydantoin was found to photofragment into isocyanic acid, CO, and methylenimine.
Towards G2G: Systems of Technology Database Systems
NASA Technical Reports Server (NTRS)
Maluf, David A.; Bell, David
2005-01-01
We present an approach and methodology for developing Government-to-Government (G2G) Systems of Technology Database Systems. G2G will deliver technologies for distributed and remote integration of technology data for internal use in analysis and planning as well as for external communications. G2G enables NASA managers, engineers, operational teams and information systems to "compose" technology roadmaps and plans by selecting, combining, extending, specializing and modifying components of technology database systems. G2G will interoperate information and knowledge that is distributed across organizational entities involved that is ideal for NASA future Exploration Enterprise. Key contributions of the G2G system will include the creation of an integrated approach to sustain effective management of technology investments that supports the ability of various technology database systems to be independently managed. The integration technology will comply with emerging open standards. Applications can thus be customized for local needs while enabling an integrated management of technology approach that serves the global needs of NASA. The G2G capabilities will use NASA s breakthrough in database "composition" and integration technology, will use and advance emerging open standards, and will use commercial information technologies to enable effective System of Technology Database systems.
A new look at the nuclear matrix.
Hancock, R
2000-07-01
The concept of the nuclear matrix, a karyoskeletal structure that serves as a support for the genome and its activities, has stimulated many studies of the association of nuclear components and functions with this structure. However, certain experimental findings are not consistent with the existence of the nuclear matrix in vivo, including our inability to visualise a corresponding structure in intact cells, the demonstrated mobility in vivo of chromatin and messenger ribonucleoprotein particles, which are claimed to be bound to the nuclear matrix, the paradoxical extractability from nuclei in low ionic strength buffers of enzymes that are found in the 2 M NaCl-insoluble matrix, and the extractability, in conditions which reproduce the intranuclear milieu, of regions of DNA (matrix or scaffold attachment regions, MAR/SARs) postulated to be bound to the nuclear matrix in vivo. This review considers the nuclear matrix model in the light of sometimes overlooked evidence that each step in its isolation may cause nuclear components to bind to it by new liaisons that do not exist in vivo. This is illustrated by experiments where nuclear-targeted green fluorescent protein is found in the nuclear matrix, and raises the possibility that MAR/SARs actually bind to DNA-binding proteins or multiprotein complexes, including replicational, transcriptional and processing machinery, and topoisomerases that are incorporated into the nuclear matrix during its preparation. Considering that the nuclear lamina forms a rigid exoskeleton, the necessity for internal skeletal structures is raised; the major roles that macromolecular crowding, phase partitioning, and charge effects are likely to play in organisation of the intranuclear space may provide new models for the compartmentalisation of proteins and functions into different nuclear domains and of chromosomes into territories.
Active Matrix OLED Test Report
NASA Technical Reports Server (NTRS)
Salazar, George
2013-01-01
This report focuses on the limited environmental testing of the AMOLED display performed as an engineering evaluation by The NASA Johnson Space Center (JSC)-specifically. EMI. Thermal Vac, and radiation tests. The AMOLED display is an active-matrix Organic Light Emitting Diode (OLED) technology. The testing provided an initial understanding of the technology and its suitability for space applications. Relative to light emitting diode (LED) displays or liquid crystal displays (LCDs), AMOLED displays provide a superior viewing experience even though they are much lighter and smaller, produce higher contrast ratio and richer colors, and require less power to operate than LCDs. However, AMOLED technology has not been demonstrated in a space environment. Therefore, some risks with the technology must be addressed before they can be seriously considered for human spaceflight. The environmental tests provided preliminary performance data on the ability of the display technology to handle some of the simulated induced space/spacecraft environments that an AMOLED display will see during a spacecraft certification test program. This engineering evaluation is part of a Space Act Agreement (SM) between The NASA/JSC and Honeywell International (HI) as a collaborative effort to evaluate the potential use of AMOLED technology for future human spaceflight missions- both government-led and commercial. Under this SM, HI is responsible for doing optical performance evaluation, as well as temperature and touch screen studies. The NASA/JSC is responsible for performing environmental testing comprised of EMI, Thermal Vac, and radiation tests. Additionally, as part of the testing, limited optical data was acquired to assess performance as the display was subjected to the induced environments. The NASA will benefit from this engineering evaluation by understanding AMOLED suitability for future use in space as well as becoming a smarter buyer (or developer) of the technology. HI benefits
Matrix metalloproteinase-2 promoter variability in psoriasis.
Vasku, Vladimir; Bienertova Vasku, Julie; Slonková, Veronika; Kanková, Katerina; Vasku, Anna
2009-07-01
The expression of matrix metalloproteinase-2 was observed to be significantly upregulated in psoriasis. The aim of this study was to associate the DNA polymorphic variants in MMP-2 promoter gene with psoriasis and/or with psoriasis phenotypes related to psoriasis and comorbid heredity. In the total of 582 Czech Caucasian individuals (386 patients with psoriasis and 196 controls of similar age and sex distribution without personal or family history of chronic disease of the skin), four MMP-2 promoter polymorphisms (-1575G/A, -1306C/T, -790T/G and -735C/T) were detected by PCR methods. A significant association of GG genotype of -790 MMP-2 polymorphism with psoriasis was observed (Pcorr = 0.04). Although no significant case-control differences in frequency of associated GG(-1575)CC(-1306)TT(-790) MMP-2 promoter genotype were observed, the genotype was found to be significantly less frequent in patients with family history of psoriasis (close as well as distant), family history of diabetes and personal history of allergy (2/11 vs. 55/32, odds ratio (OR) for GGCCTT 0.11, 95% confidential interval 0.02-0.50, Pcorr = 0.01). The significant difference between psoriatic patients with positive anamnestic data on diabetes, psoriasis and allergy compared with psoriatic patients that have only positive family history of diabetes was also observed (2/11 vs. 38/31, P = 0.009, Pcorr = 0.04; OR 0.15, 95% CI = 0.03-0.72 for psoriatic patients with GGCCTT genotype and family history of psoriasis, diabetes and personal history of allergy). To conclude, the associated GGCCTT genotype in the promoter of MMP-2 gene was less frequent in patients with positive family history of psoriasis, diabetes and personal history of allergy compared with psoriatic patients without them (2/11 vs. 68/57, P = 0.007, Pcorr = 0.04; OR = 0.15, 95% CI = 0.03-0.72 for psoriatic patients with family history of psoriasis and diabetes and with allergy). Based on our results, we suggest that the MMP-2 located in
Miyamoto, Hiroshi; Endo, Hirotoshi; Hashimoto, Naoki; Limura, Kurin; Isowa, Yukinobu; Kinoshita, Shigeharu; Kotaki, Tomohiro; Masaoka, Tetsuji; Miki, Takumi; Nakayama, Seiji; Nogawa, Chihiro; Notazawa, Atsuto; Ohmori, Fumito; Sarashina, Isao; Suzuki, Michio; Takagi, Ryousuke; Takahashi, Jun; Takeuchi, Takeshi; Yokoo, Naoki; Satoh, Nori; Toyohara, Haruhiko; Miyashita, Tomoyuki; Wada, Hiroshi; Samata, Tetsuro; Endo, Kazuyoshi; Nagasawa, Hiromichi; Asakawa, Shuichi; Watabe, Shugo
2013-10-01
In molluscs, shell matrix proteins are associated with biomineralization, a biologically controlled process that involves nucleation and growth of calcium carbonate crystals. Identification and characterization of shell matrix proteins are important for better understanding of the adaptive radiation of a large variety of molluscs. We searched the draft genome sequence of the pearl oyster Pinctada fucata and annotated 30 different kinds of shell matrix proteins. Of these, we could identified Perlucin, ependymin-related protein and SPARC as common genes shared by bivalves and gastropods; however, most gastropod shell matrix proteins were not found in the P. fucata genome. Glycinerich proteins were conserved in the genus Pinctada. Another important finding with regard to these annotated genes was that numerous shell matrix proteins are encoded by more than one gene; e.g., three ACCBP-like proteins, three CaLPs, five chitin synthase-like proteins, two N16 proteins (pearlins), 10 N19 proteins, two nacreins, four Pifs, nine shematrins, two prismalin-14 proteins, and 21 tyrosinases. This diversity of shell matrix proteins may be implicated in the morphological diversity of mollusc shells. The annotated genes reported here can be searched in P. fucata gene models version 1.1 and genome assembly version 1.0 ( http://marinegenomics.oist.jp/pinctada_fucata ). These genes should provide a useful resource for studies of the genetic basis of biomineralization and evaluation of the role of shell matrix proteins as an evolutionary toolkit among the molluscs.
Embedded systems for controlling LED matrix displays
NASA Astrophysics Data System (ADS)
Marghescu, Cristina; Drumea, Andrei
2016-12-01
LED matrix displays are a common presence in everyday life - they can be found in trains, buses, tramways, office information tables or outdoor media. The structure of the display unit is similar for all these devices, a matrix of light emitting diodes coupled between row and column lines, but there are many options for the display controller that switches these lines. Present paper analyzes different types of embedded systems that can control the LED matrix, based on single board computers, on microcontrollers with different peripheral devices or with programmable logic devices like field programmable gate arrays with implemented soft processor cores. Scalability, easiness of implementation and costs are analyzed for all proposed solutions.
High-temperature polymer matrix composites
NASA Technical Reports Server (NTRS)
Meador, Michael A.
1990-01-01
Polymers research at the NASA Lewis Research Center has produced high-temperature, easily processable resin systems, such as PMR-15. In addition, the Polymers Branch has investigated ways to improve the mechanical properties of polymers and the microcracking resistance of polymer matrix composites in response to industry need for new and improved aeropropulsion materials. Current and future research in the Polymers Branch is aimed at advancing the upper use temperature of polymer matrix composites to 700 F and beyond by developing new resins, by examining the use of fiber reinforcements other than graphite, and by developing coatings for polymer matrix composites to increase their oxidation resistance.
Visual Matrix Clustering of Social Networks
Wong, Pak C.; Mackey, Patrick S.; Foote, Harlan P.; May, Richard A.
2013-07-01
The prevailing choices to graphically represent a social network in today’s literature are a node-link graph layout and an adjacency matrix. Both visualization techniques have unique strengths and weaknesses when applied to different domain applications. In this article, we focus our discussion on adjacency matrix and how to turn the matrix-based visualization technique from merely showing pairwise associations among network actors (or graph nodes) to depicting clusters of a social network. We also use node-link layouts to supplement the discussion.
Bilateral kidney matrix stones: a rare case
Lahyani, Mounir; Rhannam, Yassine; Slaoui, Amine; Touzani, Alae; Karmouni, Tarik; Elkhader, Khalid; Koutani, Abdellatif; Andaloussi, Ahmed Ibn attya
2016-01-01
Kedney matrix stones are a rare form of calculi. Flank pain and urinary tract infections (UTI) are the most common presentations of matrix calculi. The diagnosis is usually made at surgery, but some preoperative radiographic findings might be suggestive. Open surgery was the method of choice for treatment. However, combination of ureterorenoscopy and percutaneous nephrolithotomy (PCNL) was found to be safe and effective. We report a rare case of renal and ureteral matrix stones that were diagnosed and treated by open surgery. We also describe its clinical, radiological and therapeutic features through a review of the literature. PMID:28292065
Generic construction of efficient matrix product operators
NASA Astrophysics Data System (ADS)
Hubig, C.; McCulloch, I. P.; Schollwöck, U.
2017-01-01
Matrix product operators (MPOs) are at the heart of the second-generation density matrix renormalization group (DMRG) algorithm formulated in matrix product state language. We first summarize the widely known facts on MPO arithmetic and representations of single-site operators. Second, we introduce three compression methods (rescaled SVD, deparallelization, and delinearization) for MPOs and show that it is possible to construct efficient representations of arbitrary operators using MPO arithmetic and compression. As examples, we construct powers of a short-ranged spin-chain Hamiltonian, a complicated Hamiltonian of a two-dimensional system and, as proof of principle, the long-range four-body Hamiltonian from quantum chemistry.
Learned fusion operators based on matrix completion
NASA Astrophysics Data System (ADS)
Risko, Kelly K. D.; Hester, Charles F.
2011-05-01
The efficient and timely management of imagery captured in the battlefield requires methods capable of searching the voluminous databases and extracting highly symbolic concepts. When processing images, a semantic and definition gap exists between machine representations and the user's language. Based on matrix completion techniques, we present a fusion operator that fuses imagery and expert knowledge provided by user inputs during post analysis. Specifically, an information matrix is formed from imagery and a class map as labeled by an expert. From this matrix an image operator is derived for the extraction/prediction of information from future imagery. We will present results using this technique on single mode data.
A new kind of symmetric matrix
NASA Astrophysics Data System (ADS)
Babarinsa, O.; Kamarulhaili, H.
2017-09-01
In this paper, we investigate a new category of symmetric matrix, denoted as Bn×n , which can be considered as obtained from an improper integral {Bn × n} =\\displaystyle \\mathop {\\lim }\\limitsb \\to - ∞ \\displaystyle \\int\\limits_b1 {c{x - 1}dx} ; where c = ij ‑ (i + j). The elements of the matrix are integers and are in sequence. Thus the matrix is singular (except for B 2×2) but nonsingular in its 2 × 2 connected minors. We give some deductions on its properties that other symmetric matrices do not possess.
Extracellular matrix signaling in morphogenesis and repair.
Clause, Kelly C; Barker, Thomas H
2013-10-01
The extracellular matrix (ECM) is critically important for many cellular processes including growth, differentiation, survival, and morphogenesis. Cells remodel and reshape the ECM by degrading and reassembling it, playing an active role in sculpting their surrounding environment and directing their own phenotypes. Both mechanical and biochemical molecules influence ECM dynamics in multiple ways; by releasing small bioactive signaling molecules, releasing growth factors stored within the ECM, eliciting structural changes to matrix proteins which expose cryptic sites and by degrading matrix proteins directly. The dynamic reciprocal communication between cells and the ECM plays a fundamental roll in tissue development, homeostasis, and wound healing.
Curvature and gravity actions for matrix models
NASA Astrophysics Data System (ADS)
Blaschke, Daniel N.; Steinacker, Harold
2010-08-01
We show how gravitational actions, in particular the Einstein-Hilbert action, can be obtained from additional terms in Yang-Mills matrix models. This is consistent with recent results on induced gravitational actions in these matrix models, realizing spacetime as four-dimensional brane solutions. It opens up the possibility for a controlled non-perturbative description of gravity through simple matrix models, with interesting perspectives for the problem of vacuum energy. The relation with UV/IR mixing and non-commutative gauge theory is discussed.
Scattering matrix theory for stochastic scalar fields.
Korotkova, Olga; Wolf, Emil
2007-05-01
We consider scattering of stochastic scalar fields on deterministic as well as on random media, occupying a finite domain. The scattering is characterized by a generalized scattering matrix which transforms the angular correlation function of the incident field into the angular correlation function of the scattered field. Within the accuracy of the first Born approximation this matrix can be expressed in a simple manner in terms of the scattering potential of the scatterer. Apart from determining the angular distribution of the spectral intensity of the scattered field, the scattering matrix makes it possible also to determine the changes in the state of coherence of the field produced on scattering.
A matrix model from string field theory
NASA Astrophysics Data System (ADS)
Zeze, Syoji
2016-09-01
We demonstrate that a Hermitian matrix model can be derived from level truncated open string field theory with Chan-Paton factors. The Hermitian matrix is coupled with a scalar and U(N) vectors which are responsible for the D-brane at the tachyon vacuum. Effective potential for the scalar is evaluated both for finite and large N. Increase of potential height is observed in both cases. The large N matrix integral is identified with a system of N ZZ branes and a ghost FZZT brane.
A transilient matrix for moist convection
Romps, D.; Kuang, Z.
2011-08-15
A method is introduced for diagnosing a transilient matrix for moist convection. This transilient matrix quantifies the nonlocal transport of air by convective eddies: for every height z, it gives the distribution of starting heights z{prime} for the eddies that arrive at z. In a cloud-resolving simulation of deep convection, the transilient matrix shows that two-thirds of the subcloud air convecting into the free troposphere originates from within 100 m of the surface. This finding clarifies which initial height to use when calculating convective available potential energy from soundings of the tropical troposphere.
Weak matrix elements on the lattice - Circa 1995
Soni, A.
1995-10-03
Status of weak matrix elements is reviewed. In particular, e{prime}/e, B {yields} K*{gamma}, B{sub B} and B{sub B}, are discussed and the overall situation with respect to the lattice effort and some of its phenomenological implications are summarised. For e{prime}/e the need for the relevant matrix elements is stressed in view of the forthcoming improved experiments. For some of the operators, (e.g. O{sub 6}), even bound on their matrix elements would be very helpful. On B {yields} K{degrees}{gamma}, a constant behavior of T{sub 2} appears disfavored although dependence of T{sub 2} could, of course, be milder than a simple pole. Improved data is badly needed to settle this important issue firmly, especially in view of its ramification for extractions of V{sub td} from B {yields} {rho}{gamma}. On B{sub {kappa}}, the preliminary result from JLQCD appears to contradict Sharpe et al. JLQCD data seems to fit very well to linear {alpha} dependence and leads to an appreciably lower value of B{sub {kappa}}. Four studies of B{sub {kappa}} in the {open_quotes}full{close_quotes} (n{sub f} = 2) theory indicate very little quenching effects on B{sub {kappa}}; the full theory value seems to be just a little less than the quenched result. Based on expectations from HQET, analysis of B-parameter (B{sub h}{ell}) for the heavy-light mesons via B{sub h}{ell}) = constant + constants{prime}/m{sub h}{ell} is suggested. A summary of an illustrative sample of hadron matrix elements is given and constraints on CKM parameters (e.g. V{sub td}/V{sub ts}, on the unitarity triangle and on x{sub s}/x{sub d}, emerging from the lattice calculations along with experimental results are briefly discussed. In quite a few cases, for the first time, some indication of quenching errors on weak matrix elements are now becoming available.
A graphical R-matrix atomic collision environment
NASA Astrophysics Data System (ADS)
Busby, David William
[/cal R]-matrix theory has been used effectively to compute properties characterising atomic and molecular collisions. Large Fortran packages have been developed over the past twenty-five years, which are esoteric and can sometimes be difficult to use. The aim of this research is to design and implement, using modern computer science techniques, an environment which will render the packages more straight forward and accessible. It is postulated that the interactive manipulation of graphical abstractions of the underlying physics will allow the user to concentrate on the physics of the process being studied. This approach renders the new [/cal R]-matrix packages simple to use by novice and experienced users alike, thereby improving their usefulness to the physics community. The Graphical [/cal R]-matrix Atomic Collision Environment (G[/cal R]ACE) is comprised of four graphical user interfaces. Grace expedites the construction and editing of input data stipulated by the [/cal R]-matrix program packages. Data can be entered symbolically and is extensively validated, through a series of graphical windows. The generated text file enables the [/cal R]-matrix package to be executed on a remote supercomputer to which the workstation is networked. Connected to a database of Clementi-type orbitals, pseudo facilitates the computation of pseudo-orbitals, incorporated in grace. The H-file [/cal B]rowser displays a graphical abstraction representing the physics of an inner region [/cal R]-matrix computation. This pin-points limitations which may need to be modified to improve the computation. [/cal A]nalysis provides a graphical environment on the local workstation where results of the remote computation may be displayed and interpreted. Eigenphase sums can be displayed graphically as a function of energy, where resonance fits can be performed. [/cal A]nalysis enables further points to be calculated if there is insufficient data. Effective collisions strengths can also be
Assembly of diblock copolymer grafted nanoparticles in a homopolymer blend matrix
NASA Astrophysics Data System (ADS)
Estridge, Cara; Jayaraman, Arthi
2014-03-01
Hybrid materials comprised of nanoscale fillers embedded in a polymer matrix, also terms polymer nanocomposites, are used in many applications, such as photovoltaics, photonics, automobile parts, where their macroscopic properties are governed by the nanocomposite morphology. The structure and composite morphology is controlled by the interactions of the nanoscale fillers and the polymer matrix. In this talk we show using molecular simulations that functionalization of the nanoparticle surface with AB diblock copolymer grafts is a way to tune the interactions between the grafted particle and the A and B homopolymer blend matrix. Specifically, our work demonstrates that by tailoring the copolymer composition and the copolymer grafting density one can tune the location of the copolymer grafted particles in the matrix, (e.g. within a domain versus interface of two domains). Additionally, in the case where the grafted particles locate themselves at the interface between the two domains, the interfacial tension is reduced below that possible with bare ungrafted particles at the interface.
Holzhauser, T; Vieths, S
1999-10-01
A hazelnut-specific sandwich-type ELISA based on polyclonal antisera was developed for detection of hidden hazelnut protein residues in complex food matrixes. In the absence of a food matrix, extractable protein from different native and toasted hazelnuts was detected at rates of 94 +/- 13 and 96 +/- 7% applying standards prepared from native and toasted hazelnuts, respectively. From complex food matrixes, 0.001-10% of hazelnut was recovered between 67 and 132%, in average by 106 +/- 17%. Depending on the food matrix, hazelnut protein could be detected down to the ppb (ng/g) level. Intraassay precision was <6% for hazelnut >/= 0.001% and interassay precision was <15% for hazelnut >/= 0.01%. In 12 of 28 commercial food products without labeling or declaration of hazelnut components, between 2 and 421 ppm of hazelnut protein was detected, demonstrating a remarkable presence of potentially allergenic hazelnut protein "hidden" in commercial food products.
Conformations of n-butyl imidazole: matrix isolation infrared and DFT studies.
Ramanathan, N; Sundararajan, K; Sankaran, K
2015-03-15
Conformations of n-butyl imidazole (B-IMID) were studied using matrix isolation infrared spectroscopy by trapping in argon, xenon and nitrogen matrixes using an effusive nozzle source. The experimental studies were supported by DFT computations performed at the B3LYP/6-311++G(d,p) level. Computations identified nine unique minima for B-IMID, corresponding to conformers with tg(±)tt, tg(±)g(∓)t, tg(±)g(±)t, tg(±)tg(±), tg(±)tg(∓), tg(±)g(∓)g(∓), tg(±)g(±)g(±), tg(±)g(∓)g(±) and tg(±)g(±)g(∓) structures, given in order of increasing energy. Computations of the transition state structures connecting the higher energy conformers to the global minimum, tg(±)tt structure were carried out. The barriers for the conformer inter-conversion were found to be ∼2 kcal/mol. Natural Bond Orbital (NBO) analysis was performed to understand the reasons for conformational preferences in B-IMID. Copyright © 2014 Elsevier B.V. All rights reserved.
Characterizing matrix remodeling in collagen gels using optical coherence tomography
NASA Astrophysics Data System (ADS)
Levitz, David; Hinds, Monica T.; Hanson, Stephen R.; Jacques, Steven L.
2010-02-01
Optical coherence tomography (OCT) has shown promise at non-destructively characterizing engineered tissues such as collagen gels. However, as the collagen gels develop, the OCT images lose contrast of structures as the gels develop, making visual assessment difficult. Our group proposed quantitatively characterizing these gels by fitting the optical properties from the OCT signals. In this paper, we imaged collagen gels seeded with smooth muscle cells (SMCs) over a 5-day period and used the data to measure their optical properties. Our results showed that over time, the reflectivity of the samples increased 10-fold, corresponding to a decrease in anisotropy factor g, without much change in the scattering coefficient μs. Overall, the optical properties appeared to be dominated by scattering from the collagen matrix, not the cells. However, SMCs remodeled the collagen matrix, and this collagen remodeling by the cells is what causes the observed changes in optical properties. Moreover, the data showed that the optical properties were sensitive to the activity of matrix metalloproteinases (MMPs), enzymes that break down local collagen fibrils into smaller fragments. Blocking MMPs in the SMC gels greatly impeded both the remodeling process and change in optical properties at day 5. Treating day 1 acellular gels with MMP-8 for 3 hr managed to partially reproduce the remodeling observed in SMC gels at day 5. Altogether, we conclude that matrix remodeling in general, and MMPs specifically, greatly affect the local optical properties of the sample, and OCT is a unique tool that can assess MMP activity in collagen gels both non-destructively and label free.
Penicillin G (Potassium, Sodium) Injection
... to treat and prevent certain infections caused by bacteria. Penicillin G injection is in a class of medications called penicillins. It works by killing bacteria that cause infections.Antibiotics such as penicillin G ...
Matrix metalloproteinase-7 and matrix metalloproteinase-9 in pediatric multiple sclerosis.
Yılmaz, Ünsal; Unsal, Yılmaz; Gücüyener, Kıvılcım; Kıvılcım, Gücüyener; Atak, Ayşegül; Ayşegül, Atak; Aral, Arzu; Arzu, Aral; Gürkaş, Esra; Esra, Gürkaş; Demir, Ercan; Ercan, Demir; Serdaroğlu, Ayşe; Ayşe, Serdaroğlu
2012-09-01
Matrix metalloproteinases and their tissue inhibitors play a key role in the pathogenesis of adult-onset multiple sclerosis, and were suggested as biomarkers of response to interferon-β, an established treatment in multiple sclerosis. However, data regarding pediatric population are scarce. We determined serum levels of matrix metalloproteinase-7, matrix metalloproteinase-9, and tissue inhibitor of matrix metalloproteinase-1 in children, and evaluated effects of interferon-β therapy on these measures. Serum samples from 14 children with relapsing, remitting multiple sclerosis at baseline and at month 12, and from 15 controls, were collected. Interferon-β treatment was initiated in eight patients. Mean serum matrix metalloproteinase-9 levels and matrix metalloproteinase-9/tissue inhibitor of matrix metalloproteinase-1 ratio were higher in patients compared with controls, and were reduced significantly in treated patients at month 12, but did not change in untreated patients. Mean matrix metalloproteinase-7 levels were lower in patients compared with controls, and increased significantly in the treated group, but did not change significantly in the untreated group. In pediatric multiple sclerosis, a shift in matrix metalloproteinase-9/tissue inhibitor of matrix metalloproteinase-1 balance toward proteolytic activity is evident, and interferon-β therapy demonstrates a beneficial effect on this disturbed balance. Copyright © 2012 Elsevier Inc. All rights reserved.
Cathepsin G in degenerating and healthy discal tissue.
Konttinen, Y T; Kääpä, E; Hukkanen, M; Gu, X H; Takagi, M; Santavirta, S; Alaranta, H; Li, T F; Suda, A
1999-01-01
To assess the eventual presence, tissue localization, molecular forms, amount and activity of cathepsin G in the annulus fibrosus. Normal non-autolytic disc tissue was collected from cadavers within six hours after death. Degenerate disc samples were collected from low back pain patients undergoing anterior interbody fusion due to severe, discographically verified and painful disc degeneration, and from the posterior parts of intervertebral discs from 10 patients undergoing microscopic discoidectomy because of intervertebral herniation. Avidin-biotinperxidase complex staining of cathepsin G was quantitated by morphometry. Cellular localization was analyzed using double immunofluorescence staining of cathepsin G and CD68, proline 4-hydroxylase or von Willebrand factor. Neutral salt extracts were analyzed by using synthetic cathepsin G substrate in spectrophotometry, dot-immunoblotting and Western blotting. Histological and morphometric image analysis showed increased cellularity, increased numbers of cathepsin G positive cells and neovascularization in degenerated discs compared to control discs. Neutral salt extract of disc tissue, degenerated or normal, in contrast to control material from synovial capsular tissue, did not contain measurable cathepsin G activity, although immunoreactive enzyme was detected in dot-immunoblotting. Western blotting demonstrated that the discal cathepsin G had an apparent molecular weight of 27 kDa. Due to its properties and localization in normal and pathologically altered tissue, cathepsin G probably plays both a direct and an indirect role in extracellular matrix degradation in the annulus fibrosus. Extracted cationic cathepsin G was immunoreactive, but was functionally inhibited by serpins or, more likely, by polyanionic proteoglycans and saccharins derived from the connective tissue matrix of the annulus fibrosus.
ERIC Educational Resources Information Center
Jensen, Arthur R.; Weng, Li-Jen
1994-01-01
The stability of psychometric "g," the general factor of intelligence, is investigated in simulated correlation matrices and in typical empirical data from a large battery of mental tests. "G" is robust and almost invariant across methods of analysis. A reasonable strategy for estimating "g" is suggested. (SLD)
Ginsparg, P.
1991-01-01
These are introductory lectures for a general audience that give an overview of the subject of matrix models and their application to random surfaces, 2d gravity, and string theory. They are intentionally 1.5 years out of date.
Ginsparg, P.
1991-12-31
These are introductory lectures for a general audience that give an overview of the subject of matrix models and their application to random surfaces, 2d gravity, and string theory. They are intentionally 1.5 years out of date.
Constrained Nonnegative Matrix Factorization for Image Representation.
Liu, Haifeng; Wu, Zhaohui; Li, Xuelong; Cai, Deng; Huang, Thomas S
2012-07-01
Nonnegative matrix factorization (NMF) is a popular technique for finding parts-based, linear representations of nonnegative data. It has been successfully applied in a wide range of applications such as pattern recognition, information retrieval, and computer vision. However, NMF is essentially an unsupervised method and cannot make use of label information. In this paper, we propose a novel semi-supervised matrix decomposition method, called Constrained Nonnegative Matrix Factorization (CNMF), which incorporates the label information as additional constraints. Specifically, we show how explicitly combining label information improves the discriminating power of the resulting matrix decomposition. We explore the proposed CNMF method with two cost function formulations and provide the corresponding update solutions for the optimization problems. Empirical experiments demonstrate the effectiveness of our novel algorithm in comparison to the state-of-the-art approaches through a set of evaluations based on real-world applications.
On matrix cracking in fiber reinforced ceramics
NASA Astrophysics Data System (ADS)
Chiang, Yih-Cheng; Wang, A. S. D.; Chou, Tsu-Wei
1993-07-01
THISPAPER addresses critical stress at the propagation of a fiber-bridged matrix crack of arbitrary length in fiber-reinforced brittle matrix composites. The formulation of the problem follows the approach adopted earlier by Marshall, Cox and Evans, but a new shear-lag model that accounts for the matrix shear deformation above the slipping region is used here to derive the relationship between the crack opening displacement and the crack surface closure traction. The inclusion of the matrix shear deformation above the slipping region significantly affects the calculated crack tip stress intensity factor and the prediction of the critical stress at the propagation of the crack. Illustrative examples are cited using three available composite systems of SiC-borosilicate, C-borosilicate and Nicalon-lithium-aluminosilicate (LAS).
Software for Fault-Tolerant Matrix Multiplication
NASA Technical Reports Server (NTRS)
Katz, Daniel; Tisdale, Edwin; Quintana-Orti, Enrique; Gunnels, John; van de Geijn, Robert
2004-01-01
Formal Linear Algebra Recovery Environment is a computer program for high-performance, fault-tolerant matrix multiplication. The program is based on an extension of the prior theory and practice of fault-tolerant matrix matrix multiplication of the form C = AB. This extension provides low-overhead methods for detecting errors, not only in C, but also in A and/or B. These methods enable the detection of all errors as long as, in a given case, only one entry in A, B, or C is corrupted. The program also provides for following a low-overhead rollback approach to correct errors once detected. Results of computational experiments have demonstrated that the methods implemented in this program work well in practice while imposing an acceptably low level of overhead, relative to high-performance matrix-multiplication methods that do not afford fault tolerance.
Axial grading of inert matrix fuels
Recktenwald, G. D.; Deinert, M. R.
2012-07-01
Burning actinides in an inert matrix fuel to 750 MWd/kg IHM results in a significant reduction in transuranic isotopes. However, achieving this level of burnup in a standard light water reactor would require residence times that are twice that of uranium dioxide fuels. The reactivity of an inert matrix assembly at the end of life is less than 1/3 of its beginning of life reactivity leading to undesirable radial and axial power peaking in the reactor core. Here we show that axial grading of the inert matrix fuel rods can reduce peaking significantly. Monte Carlo simulations are used to model the assembly level power distributions in both ungraded and graded fuel rods. The results show that an axial grading of uranium dioxide and inert matrix fuels with erbium can reduces power peaking by more than 50% in the axial direction. The reduction in power peaking enables the core to operate at significantly higher power. (authors)
Chondrule-matrix relationships in chondritic meteorites
NASA Technical Reports Server (NTRS)
Brearley, A. J.
1994-01-01
The relationship between chondrules and matrix (fine grained material with a grain size less than 5 micrometers) in chondritic meteorites has been the subject of considerable controversy and no consensus currently exists. The coexistence of these two components in meteorites with bulk compositions that deviate only slightly from CI abundances suggests that cosmochemically their origins are closely linked. Any consideration of the relationship between chondrules and matrix hinges to a large degree on the origin of matrix. The entire spectrum of models exists from matrix as a nebular product to derivation entirely from chondrules. Early models of solar nebular evolution viewed chondrites as a two-component mixture of high- and low-temperature condensates. However, this model has been challenged by the recognition that the nebula was probably not uniformly vaporized.
Supersymmetric SYK model and random matrix theory
NASA Astrophysics Data System (ADS)
Li, Tianlin; Liu, Junyu; Xin, Yuan; Zhou, Yehao
2017-06-01
In this paper, we investigate the effect of supersymmetry on the symmetry classification of random matrix theory ensembles. We mainly consider the random matrix behaviors in the N=1 supersymmetric generalization of Sachdev-Ye-Kitaev (SYK) model, a toy model for two-dimensional quantum black hole with supersymmetric constraint. Some analytical arguments and numerical results are given to show that the statistics of the supersymmetric SYK model could be interpreted as random matrix theory ensembles, with a different eight-fold classification from the original SYK model and some new features. The time-dependent evolution of the spectral form factor is also investigated, where predictions from random matrix theory are governing the late time behavior of the chaotic hamiltonian with supersymmetry.
Structural Analysis and Matrix Interpretive System /SAMIS/
NASA Technical Reports Server (NTRS)
1967-01-01
Structural Analysis and Matrix Interpretive System eliminates high-speed digital computer restrictions of lack of generalization and lack of flexibility. Programming concepts of the system are standardization, modularity, and programming for intermediate-size problems.
Emergent spacetime & quantum entanglement in matrix theory
NASA Astrophysics Data System (ADS)
Sahakian, Vatche; Tawabutr, Yossathorn; Yan, Cynthia
2017-08-01
In the context of the Bank-Fishler-Shenker-Susskind Matrix theory, we analyze a spherical membrane in light-cone M theory along with two asymptotically distant probes. In the appropriate energy regime, we find that the membrane behaves like a smeared Matrix black hole; and the spacetime geometry seen by the probes can become non-commutative even far away from regions of Planckian curvature. This arises from non-linear Matrix interactions where fast matrix modes lift a flat direction in the potential — akin to the Paul trap phenomenon in atomic physics. In the regime where we do have a notion of emergent spacetime, we show that there is non-zero entanglement entropy between supergravity modes on the membrane and the probes. The computation can easily be generalized to other settings, and this can help develop a dictionary between entanglement entropy and local geometry — similar to Ryu-Takayanagi but instead for asymptotically flat backgrounds.
Microstructure of Matrix in UHTC Composites
NASA Technical Reports Server (NTRS)
Johnson, Sylvia; Stackpoole, Margaret; Gusman, Michael I.; Chavez-Garia Jose; Doxtad, Evan
2011-01-01
Approaches to controlling the microstructure of Ultra High Temperature Ceramics (UHTCs) are described.. One matrix material has been infiltrated into carbon weaves to make composite materials. The microstructure of these composites is described.
Nuclear waste storage container with metal matrix
Sump, Kenneth R.
1978-01-01
The invention relates to a storage container for high-level waste having a metal matrix for the high-level waste, thereby providing greater impact strength for the waste container and increasing heat transfer properties.
Matrix Gla protein in tumoral pathology.
Gheorghe, Simona Roxana; Crăciun, Alexandra Mărioara
2016-01-01
Matrix Gla protein is a vitamin K-dependent protein secreted by chondrocytes and vascular smooth muscle cells. The presence of matrix Gla protein was reported in arterial and venous walls, lungs, kidney, uterus, heart, tooth cementum and eyes. Several studies identified matrix Gla protein in tumoral pathology. Until recently, it was thought to only have an inhibitory role of physiological and ectopic calcification. New studies demonstrated that it also has a role in physiological and pathological angiogenesis, as well as in tumorigenesis. The aim of this review is to report the latest findings related to the expression and clinical implications of matrix Gla protein in different types of cancer with an emphasis on cerebral tumors.
Superfund Chemical Data Matrix (SCDM) Query - Popup
This site allows you to to easily query the Superfund Chemical Data Matrix (SCDM) and generate a list of the corresponding Hazardous Ranking System (HRS) factor values, benchmarks, and data elements that you need.
Superfund Chemical Data Matrix (SCDM) Query
This site allows you to to easily query the Superfund Chemical Data Matrix (SCDM) and generate a list of the corresponding Hazard Ranking System (HRS) factor values, benchmarks, and data elements that you need.
Contact matrix in dilute quantum systems
NASA Astrophysics Data System (ADS)
Zhang, Shao-Liang; He, Mingyuan; Zhou, Qi
2017-06-01
Contact has been well established as an important quantity to govern dilute quantum systems, in which the pairwise correlation at short distance traces a broad range of thermodynamic properties. So far, most studies have focused on contact in individual angular momentum channels. Here we point out that, to have a complete description of the pairwise correlation in a general dilute quantum systems, contact should be defined as a matrix. Whereas the diagonal terms of such a matrix include contact of all partial wave scatterings, the off-diagonal terms characterize the coherence of the asymptotic pairwise wave function in the angular momentum space and determine important thermodynamic quantities including the momentum distribution. The contact matrix allows physicists to access unexplored connections between short-range correlations and macroscopic quantum phenomena. As an example, we show the direct connection between the contact matrix and order parameters of a superfluid with mixed partial waves.
Comix, a New Matrix Element Generator
Gleisberg, Tanju; Hoche, Stefan; /Durham U., IPPP
2008-09-03
We present a new tree-level matrix element generator, based on the color dressed Berends-Giele recursive relations. We discuss two new algorithms for phase space integration, dedicated to be used with large multiplicities and color sampling.
Matrix Models, Emergent Spacetime and Symmetry Breaking
Grosse, Harald; Steinacker, Harold; Lizzi, Fedele
2009-12-15
We discuss how a matrix model recently shown to describe emergent gravity may contain extra degrees of freedom which reproduce some characteristics of the standard model, in particular the breaking of symmetries and the correct quantum numbers of fermions.
Celsian Glass-Ceramic Matrix Composites
NASA Technical Reports Server (NTRS)
Bansal, Narottam P.; Dicarlo, James A.
1996-01-01
Glass-ceramic matrix reinforced fiber composite materials developed for use in low dielectric applications, such as radomes. Materials strong and tough, exhibit low dielectric properties, and endure high temperatures.
Amyloid Structures as Biofilm Matrix Scaffolds
Taglialegna, Agustina; Lasa, Iñigo
2016-01-01
Recent insights into bacterial biofilm matrix structures have induced a paradigm shift toward the recognition of amyloid fibers as common building block structures that confer stability to the exopolysaccharide matrix. Here we describe the functional amyloid systems related to biofilm matrix formation in both Gram-negative and Gram-positive bacteria and recent knowledge regarding the interaction of amyloids with other biofilm matrix components such as extracellular DNA (eDNA) and the host immune system. In addition, we summarize the efforts to identify compounds that target amyloid fibers for therapeutic purposes and recent developments that take advantage of the amyloid structure to engineer amyloid fibers of bacterial biofilm matrices for biotechnological applications. PMID:27185827
Optimal matrix approximants in structural identification
NASA Technical Reports Server (NTRS)
Beattie, C. A.; Smith, S. W.
1992-01-01
Problems of model correlation and system identification are central in the design, analysis, and control of large space structures. Of the numerous methods that have been proposed, many are based on finding minimal adjustments to a model matrix sufficient to introduce some desirable quality into that matrix. In this work, several of these methods are reviewed, placed in a modern framework, and linked to other previously known ideas in computational linear algebra and optimization. This new framework provides a point of departure for a number of new methods which are introduced here. Significant among these is a method for stiffness matrix adjustment which preserves the sparsity pattern of an original matrix, requires comparatively modest computational resources, and allows robust handling of noisy modal data. Numerical examples are included to illustrate the methods presented herein.
Spin Matrix theory: a quantum mechanical model of the AdS/CFT correspondence
NASA Astrophysics Data System (ADS)
Harmark, Troels; Orselli, Marta
2014-11-01
We introduce a new quantum mechanical theory called Spin Matrix theory (SMT). The theory is interacting with a single coupling constant g and is based on a Hilbert space of harmonic oscillators with a spin index taking values in a Lie (super)algebra representation as well as matrix indices for the adjoint representation of U( N). We show that SMT describes super-Yang-Mills theory (SYM) near zero-temperature critical points in the grand canonical phase diagram. Equivalently, SMT arises from non-relativistic limits of SYM. Even though SMT is a non-relativistic quantum mechanical theory it contains a variety of phases mimicking the AdS/CFT correspondence. Moreover, the g → ∞ limit of SMT can be mapped to the supersymmetric sector of string theory on AdS5 × S 5. We study SU(2) SMT in detail. At large N and low temperatures it is a theory of spin chains that for small g resembles planar gauge theory and for large g a non-relativistic string theory. When raising the temperature a partial deconfinement transition occurs due to finite- N effects. For sufficiently high temperatures the partially deconfined phase has a classical regime. We find a matrix model description of this regime at any coupling g. Setting g = 0 it is a theory of N 2 + 1 harmonic oscillators while for large g it becomes 2 N harmonic oscillators.
Analysis of local delaminations caused by angle ply matrix cracks
Salpekar, S.A.; Obrien, T.K.; Shivakumar, K.N.
1993-11-01
Two different families of graphite/epoxy laminates with similar layups but different stacking sequences, (0,theta,-theta) sub s and (-theta/theta/0) sub s were analyzed using three-dimensional finite element analysis for theta = 15 and 30 degrees. Delaminations were modeled in the -theta/theta interface, bounded by a matrix crack and the stress free edge. The total strain energy release rate, G, along the delamination front was computed using three different techniques: the virtual crack closure technique (VCCT), the equivalent domain Integral (EDI) technique, and a global energy balance technique. The opening fracture mode component of the strain energy release rate, Gl, along the delamination front was also computed for various delamination lengths using VCCT. The effect of residual thermal and moisture stresses on G was evaluated.
Analysis of local delaminations caused by angle ply matrix cracks
NASA Technical Reports Server (NTRS)
Salpekar, Satish A.; Obrien, T. Kevin; Shivakumar, K. N.
1993-01-01
Two different families of graphite/epoxy laminates with similar layups but different stacking sequences, (0,theta,-theta) sub s and (-theta/theta/0) sub s were analyzed using three-dimensional finite element analysis for theta = 15 and 30 degrees. Delaminations were modeled in the -theta/theta interface, bounded by a matrix crack and the stress free edge. The total strain energy release rate, G, along the delamination front was computed using three different techniques: the virtual crack closure technique (VCCT), the equivalent domain Integral (EDI) technique, and a global energy balance technique. The opening fracture mode component of the strain energy release rate, Gl, along the delamination front was also computed for various delamination lengths using VCCT. The effect of residual thermal and moisture stresses on G was evaluated.
NASA Technical Reports Server (NTRS)
Hughes-Fulford, M.; Gilbertson, V.
1999-01-01
The well-defined osteoblast line, MC3T3-E1 was used to examine fibronectin (FN) mRNA levels, protein synthesis, and extracellular FN matrix accumulation after growth activation in spaceflight. These osteoblasts produce FN extracellular matrix (ECM) known to regulate adhesion, differentiation, and function in adherent cells. Changes in bone ECM and osteoblast cell shape occur in spaceflight. To determine whether altered FN matrix is a factor in causing these changes in spaceflight, quiescent osteoblasts were launched into microgravity and were then sera activated with and without a 1-gravity field. Synthesis of FN mRNA, protein, and matrix were measured after activation in microgravity. FN mRNA synthesis is significantly reduced in microgravity (0-G) when compared to ground (GR) osteoblasts flown in a centrifuge simulating earth's gravity (1-G) field 2.5 h after activation. However, 27.5 h after activation there were no significant differences in mRNA synthesis. A small but significant reduction of FN protein was found in the 0-G samples 2.5 h after activation. Total FN protein 27.5 h after activation showed no significant difference between any of the gravity conditions, however, there was a fourfold increase in absolute amount of protein synthesized during the incubation. Using immunofluorescence, we found no significant differences in the amount or in the orientation of the FN matrix after 27.5 h in microgravity. These results demonstrate that FN is made by sera-activated osteoblasts even during exposure to microgravity. These data also suggest that after a total period of 43 h of spaceflight FN transcription, translation, or altered matrix assembly is not responsible for the altered cell shape or altered matrix formation of osteoblasts.
NASA Technical Reports Server (NTRS)
Hughes-Fulford, M.; Gilbertson, V.
1999-01-01
The well-defined osteoblast line, MC3T3-E1 was used to examine fibronectin (FN) mRNA levels, protein synthesis, and extracellular FN matrix accumulation after growth activation in spaceflight. These osteoblasts produce FN extracellular matrix (ECM) known to regulate adhesion, differentiation, and function in adherent cells. Changes in bone ECM and osteoblast cell shape occur in spaceflight. To determine whether altered FN matrix is a factor in causing these changes in spaceflight, quiescent osteoblasts were launched into microgravity and were then sera activated with and without a 1-gravity field. Synthesis of FN mRNA, protein, and matrix were measured after activation in microgravity. FN mRNA synthesis is significantly reduced in microgravity (0-G) when compared to ground (GR) osteoblasts flown in a centrifuge simulating earth's gravity (1-G) field 2.5 h after activation. However, 27.5 h after activation there were no significant differences in mRNA synthesis. A small but significant reduction of FN protein was found in the 0-G samples 2.5 h after activation. Total FN protein 27.5 h after activation showed no significant difference between any of the gravity conditions, however, there was a fourfold increase in absolute amount of protein synthesized during the incubation. Using immunofluorescence, we found no significant differences in the amount or in the orientation of the FN matrix after 27.5 h in microgravity. These results demonstrate that FN is made by sera-activated osteoblasts even during exposure to microgravity. These data also suggest that after a total period of 43 h of spaceflight FN transcription, translation, or altered matrix assembly is not responsible for the altered cell shape or altered matrix formation of osteoblasts.
Genetic dissection of peroxisome-associated matrix protein degradation in Arabidopsis thaliana.
Burkhart, Sarah E; Lingard, Matthew J; Bartel, Bonnie
2013-01-01
Peroxisomes are organelles that sequester certain metabolic pathways; many of these pathways generate H(2)O(2), which can damage proteins. However, little is known about how damaged or obsolete peroxisomal proteins are degraded. We exploit developmentally timed peroxisomal content remodeling in Arabidopsis thaliana to elucidate peroxisome-associated protein degradation. Isocitrate lyase (ICL) is a peroxisomal glyoxylate cycle enzyme necessary for early seedling development. A few days after germination, photosynthesis begins and ICL is degraded. We previously found that ICL is stabilized when a peroxisome-associated ubiquitin-conjugating enzyme and its membrane anchor are both mutated, suggesting that matrix proteins might exit the peroxisome for ubiquitin-dependent cytosolic degradation. To identify additional components needed for peroxisome-associated matrix protein degradation, we mutagenized a line expressing GFP-ICL, which is degraded similarly to endogenous ICL, and identified persistent GFP-ICL fluorescence (pfl) mutants. We found three pfl mutants that were defective in PEROXIN14 (PEX14/At5g62810), which encodes a peroxisomal membrane protein that assists in importing proteins into the peroxisome matrix, indicating that proteins must enter the peroxisome for efficient degradation. One pfl mutant was missing the peroxisomal 3-ketoacyl-CoA thiolase encoded by the PEROXISOME DEFECTIVE1 (PED1/At2g33150) gene, suggesting that peroxisomal metabolism influences the rate of matrix protein degradation. Finally, one pfl mutant that displayed normal matrix protein import carried a novel lesion in PEROXIN6 (PEX6/At1g03000), which encodes a peroxisome-tethered ATPase that is involved in recycling matrix protein receptors back to the cytosol. The isolation of pex6-2 as a pfl mutant supports the hypothesis that matrix proteins can exit the peroxisome for cytosolic degradation.
Autoantibodies against matrix metalloproteinase-1 in patients with localized scleroderma.
Tomimura, Saori; Ogawa, Fumihide; Iwata, Yohei; Komura, Kazuhiro; Hara, Toshihide; Muroi, Eiji; Takenaka, Motoi; Shimizu, Kazuhiro; Hasegawa, Minoru; Fujimoto, Manabu; Sato, Shinichi
2008-10-01
Localized scleroderma (LSc) is characterized by cutaneous fibrosis and various autoantibodies. To determine the presence or levels of antibodies (Abs) against matrix metalloproteinase (MMP)-1 and their clinical relevance in LSc. Anti-MMP-1 Ab was examined by ELISA (Enzyme-Linked ImmunoSorbent Assay) and immunoblotting using human recombinant MMP-1. MMP-1 collagenase activity was determined using biotinylated collagen as substrate and the amount of cleaved biotinylated fragments of collagen by MMP-1 was measured by ELISA. LSc patients exhibited significantly elevated IgG anti-MMP-1 Ab levels relative to normal controls at similar level of patients with systemic sclerosis (SSc). However, IgG anti-MMP-1 Ab levels were comparable among the 3 LSc subgroups: morphea, linear scleroderma, and generalized morphea. When absorbance values higher than the mean+2S.D. of normal controls were considered positive, IgG or IgM anti-MMP-1 Ab was found in 46% and 49% of total LSc patients and SSc patients, respectively. Anti-MMP-1 Ab was detected most frequently in morphea patients (60%), followed by linear scleroderma patients (47%) and then generalized morphea patients (25%). LSc patients positive for IgG anti-MMP-1 Ab had elevated levels of IgG anti-single-stranded DNA Ab, IgG anti-nucleosome Ab, and shorter disease duration relative to those negative. The presence of anti-MMP-1 Ab in LSc patients was confirmed by immunoblotting. IgG isolated from LSc patients' sera positive for IgG anti-MMP-1 Ab by ELISA inhibited MMP-1 collagenase activity. These results suggest that anti-MMP-1 autoantibody is a novel autoantibody in LSc.
Nanophosphor composite scintillator with a liquid matrix
McKigney, Edward Allen; Burrell, Anthony Keiran; Bennett, Bryan L.; Cooke, David Wayne; Ott, Kevin Curtis; Bacrania, Minesh Kantilal; Del Sesto, Rico Emilio; Gilbertson, Robert David; Muenchausen, Ross Edward; McCleskey, Thomas Mark
2010-03-16
An improved nanophosphor scintillator liquid comprises nanophosphor particles in a liquid matrix. The nanophosphor particles are optionally surface modified with an organic ligand. The surface modified nanophosphor particle is essentially surface charge neutral, thereby preventing agglomeration of the nanophosphor particles during dispersion in a liquid scintillator matrix. The improved nanophosphor scintillator liquid may be used in any conventional liquid scintillator application, including in a radiation detector.
Application of Fuzzy Logic to Matrix FMECA
NASA Astrophysics Data System (ADS)
Shankar, N. Ravi; Prabhu, B. S.
2001-04-01
A methodology combining the benefits of Fuzzy Logic and Matrix FMEA is presented in this paper. The presented methodology extends the risk prioritization beyond the conventional Risk Priority Number (RPN) method. Fuzzy logic is used to calculate the criticality rank. Also the matrix approach is improved further to develop a pictorial representation retaining all relevant qualitative and quantitative information of several FMEA elements relationships. The methodology presented is demonstrated by application to an illustrative example.
Mechanisms balancing skeletal matrix synthesis and degradation.
Blair, Harry C; Zaidi, Mone; Schlesinger, Paul H
2002-01-01
Bone is regulated by evolutionarily conserved signals that balance continuous differentiation of bone matrix-producing cells against apoptosis and matrix removal. This is continued from embryogenesis, where the skeleton differentiates as a solid mass and is shaped into separate bones by cell death and proteolysis. The two major tissues of the skeleton are avascular cartilage, with an extracellular matrix based on type II collagen and hydrophilic proteoglycans, and bone, a stronger and lighter material based on oriented type I collagen and hydroxyapatite. Both differentiate from the same mesenchymal stem cells. This differentiation is regulated by a family of related signals centred on bone morphogenic proteins. Fibroblast growth factors, Indian hedgehog and parathyroid hormone-related protein are important in determining the type of matrix and the relation of skeletal and non-skeletal structures. Removal of mineralized matrix involves apoptosis of matrix cells and differentiation of acid-secreting cells (osteoclasts) from macrophage precursors. Key regulators of matrix removal are signals in the tumour-necrosis-factor family. Osteoclasts dissolve bone by isolating a region of the matrix and secreting HCl and proteinases at that site. Successive cycles of removal and replacement allow growth, repair and remodelling. The signals for bone turnover are predominantly cell-membrane-associated, allowing very specific spatial regulation. In addition to its support function, bone is a reservoir of Ca2+, PO3-(4) and OH-. Secondary modulation of mineral secretion and bone degradation are mediated by humoral signals, including parathyroid hormone and vitamin D, as well as the cytokines that also regulate the underlying cell differentiation. PMID:12023876
Micromechanical Modeling of Woven Metal Matrix Composites
NASA Technical Reports Server (NTRS)
Bednarcyk, Brett A.; Pindera, Marek-Jerzy
1997-01-01
This report presents the results of an extensive micromechanical modeling effort for woven metal matrix composites. The model is employed to predict the mechanical response of 8-harness (8H) satin weave carbon/copper (C/Cu) composites. Experimental mechanical results for this novel high thermal conductivity material were recently reported by Bednarcyk et al. along with preliminary model results. The micromechanics model developed herein is based on an embedded approach. A micromechanics model for the local (micro-scale) behavior of the woven composite, the original method of cells (Aboudi), is embedded in a global (macro-scale) micromechanics model (the three-dimensional generalized method of cells (GMC-3D) (Aboudi). This approach allows representation of true repeating unit cells for woven metal matrix composites via GMC-3D, and representation of local effects, such as matrix plasticity, yarn porosity, and imperfect fiber-matrix bonding. In addition, the equations of GMC-3D were reformulated to significantly reduce the number of unknown quantities that characterize the deformation fields at the microlevel in order to make possible the analysis of actual microstructures of woven composites. The resulting micromechanical model (WCGMC) provides an intermediate level of geometric representation, versatility, and computational efficiency with respect to previous analytical and numerical models for woven composites, but surpasses all previous modeling work by allowing the mechanical response of a woven metal matrix composite, with an elastoplastic matrix, to be examined for the first time. WCGMC is employed to examine the effects of composite microstructure, porosity, residual stresses, and imperfect fiber-matrix bonding on the predicted mechanical response of 8H satin C/Cu. The previously reported experimental results are summarized, and the model predictions are compared to monotonic and cyclic tensile and shear test data. By considering appropriate levels of porosity
Semiclassical matrix elements from periodic orbits
NASA Technical Reports Server (NTRS)
Eckhardt, B.; Fishman, S.; Mueller, K.; Wintgen, D.
1992-01-01
An extension of Gutzwiller's (1967, 1969, 1970, 1971, 1990) semiclassical theory for chaotic systems that allows a determination of matrix elements in terms of classical periodic orbits. Associated zeta functions are derived. The semiclassical predictions are found to be in good agreement with Fourier transforms of quantum spectra of hydrogen in a magnetic field. Expressions for off-diagonal matrix elements are derived that are extensions of the Bohr correspondence relations for integrable systems.
Semisupervised kernel matrix learning by kernel propagation.
Hu, Enliang; Chen, Songcan; Zhang, Daoqiang; Yin, Xuesong
2010-11-01
The goal of semisupervised kernel matrix learning (SS-KML) is to learn a kernel matrix on all the given samples on which just a little supervised information, such as class label or pairwise constraint, is provided. Despite extensive research, the performance of SS-KML still leaves some space for improvement in terms of effectiveness and efficiency. For example, a recent pairwise constraints propagation (PCP) algorithm has formulated SS-KML into a semidefinite programming (SDP) problem, but its computation is very expensive, which undoubtedly restricts PCPs scalability in practice. In this paper, a novel algorithm, called kernel propagation (KP), is proposed to improve the comprehensive performance in SS-KML. The main idea of KP is first to learn a small-sized sub-kernel matrix (named seed-kernel matrix) and then propagate it into a larger-sized full-kernel matrix. Specifically, the implementation of KP consists of three stages: 1) separate the supervised sample (sub)set X(l) from the full sample set X; 2) learn a seed-kernel matrix on X(l) through solving a small-scale SDP problem; and 3) propagate the learnt seed-kernel matrix into a full-kernel matrix on X . Furthermore, following the idea in KP, we naturally develop two conveniently realizable out-of-sample extensions for KML: one is batch-style extension, and the other is online-style extension. The experiments demonstrate that KP is encouraging in both effectiveness and efficiency compared with three state-of-the-art algorithms and its related out-of-sample extensions are promising too.
Random Matrix Analysis of Human EEG Data
NASA Astrophysics Data System (ADS)
Šeba, P.
2003-11-01
We use random matrix theory to demonstrate the existence of generic and subject-independent features of the ensemble of correlation matrices extracted from human EEG data. In particular, the spectral density as well as the level spacings was analyzed and shown to be generic and subject independent. We also investigate number variance distributions. In this case we show that when the measured subject is visually stimulated the number variance displays deviations from the random matrix prediction.
Shrinkage approach for EEG covariance matrix estimation.
Beltrachini, Leandro; von Ellenrieder, Nicolas; Muravchik, Carlos H
2010-01-01
We present a shrinkage estimator for the EEG spatial covariance matrix of the background activity. We show that such an estimator has some advantages over the maximum likelihood and sample covariance estimators when the number of available data to carry out the estimation is low. We find sufficient conditions for the consistency of the shrinkage estimators and results concerning their numerical stability. We compare several shrinkage schemes and show how to improve the estimator by incorporating known structure of the covariance matrix.
Semiclassical matrix elements from periodic orbits
NASA Technical Reports Server (NTRS)
Eckhardt, B.; Fishman, S.; Mueller, K.; Wintgen, D.
1992-01-01
An extension of Gutzwiller's (1967, 1969, 1970, 1971, 1990) semiclassical theory for chaotic systems that allows a determination of matrix elements in terms of classical periodic orbits. Associated zeta functions are derived. The semiclassical predictions are found to be in good agreement with Fourier transforms of quantum spectra of hydrogen in a magnetic field. Expressions for off-diagonal matrix elements are derived that are extensions of the Bohr correspondence relations for integrable systems.
Fibre-Matrix Interaction in Soft Tissue
Guo, Zaoyang
2010-05-21
Although the mechanical behaviour of soft tissue has been extensively studied, the interaction between the collagen fibres and the ground matrix has not been well understood and is therefore ignored by most constitutive models of soft tissue. In this paper, the human annulus fibrosus is used as an example and the potential fibre-matrix interaction is identified by careful investigation of the experimental results of biaxial and uniaxial testing of the human annulus fibrosus. First, the uniaxial testing result of the HAF along the axial direction is analysed and it is shown that the mechanical behaviour of the ground matrix can be well simulated by the incompressible neo-Hookean model when the collagen fibres are all under contraction. If the collagen fibres are stretched, the response of the ground matrix can still be described by the incompressible neo-Hookean model, but the effective stiffness of the matrix depends on the fibre stretch ratio. This stiffness can be more than 10 times larger than the one obtained with collagen fibres under contraction. This phenomenon can only be explained by the fibre-matrix interaction. Furthermore, we find that the physical interpretation of this interaction includes the inhomogeneity of the soft tissue and the fibre orientation dispersion. The dependence of the tangent stiffness of the matrix on the first invariant of the deformation tensor can also be explained by the fibre orientation dispersion. The significant effect of the fibre-matrix interaction strain energy on mechanical behaviour of the soft tissue is also illustrated by comparing some simulation results.
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. -- Highlights: •Mitochondrial matrix contains ubiquitinated proteins. •Ubiquitination occurs most probably in the matrix. •Dma1p is a ubiquitin ligase present in mitochondrial preparations.
Polymer Matrix Composite Material Oxygen Compatibility
NASA Technical Reports Server (NTRS)
Owens, Tom
2001-01-01
Carbon fiber/polymer matrix composite materials look promising as a material to construct liquid oxygen (LOX) tanks. Based on mechanical impact tests the risk will be greater than aluminum, however, the risk can probably be managed to an acceptable level. Proper tank design and operation can minimize risk. A risk assessment (hazard analysis) will be used to determine the overall acceptability for using polymer matrix composite materials.
Fuel cell with electrolyte matrix assembly
Kaufman, Arthur; Pudick, Sheldon; Wang, Chiu L.
1988-01-01
This invention is directed to a fuel cell employing a substantially immobilized electrolyte imbedded therein and having a laminated matrix assembly disposed between the electrodes of the cell for holding and distributing the electrolyte. The matrix assembly comprises a non-conducting fibrous material such as silicon carbide whiskers having a relatively large void-fraction and a layer of material having a relatively small void-fraction.
Molten carbonate fuel cell matrix tape
Vine, R.W.; Schroll, C.R.; Reiser, C.A.
1986-04-08
A matrix material for a molten carbonate fuel cell is described comprising particles inert to molten carbonate electrolyte having a particle size less than about 1 micron, ceramic particles having a particle size greater than about 25 microns, and an organic polymeric binder material, the binder material being present in an amount at least about 35% by volume, the matrix material being flexible, pliable, and compliant at room temperature.
Cryogenic regenerator including sarancarbon heat conduction matrix
NASA Technical Reports Server (NTRS)
Jones, Jack A. (Inventor); Petrick, S. Walter (Inventor); Britcliffe, Michael J. (Inventor)
1989-01-01
A saran carbon matrix is employed to conduct heat through the heat storing volume of a cryogenic regenerator. When helium is adsorbed into the saran carbon matrix, the combination exhibits a volumetric specific heat much higher than previously used lead balls. A helium adsorbed saran regenerator should allow much lower refrigerator temperatures than those practically obtainable with lead based regenerators for regenerator type refrigeration systems.
Sensitivity of solar g-modes to varying G cosmologies
NASA Technical Reports Server (NTRS)
Guenther, D. B.; Sills, Ken; Demarque, Pierre; Krauss, Lawrence M.
1995-01-01
The sensitivity of the solar g-mode oscillation spectrum to variability in the universal gravitational constant G is described. Solar models in varying G cosmologies were constructed by evolving a zero-age main-sequence stellar model to the Sun's current age, while allowing the value of G to change according to the power law G(t) proportional to t(exp -beta), where Beta approximately equals delta G/GH and H is the Hubble constant. All solar models were constrained to the observed luminosity and radius at the current age of the Sun by adjusting the helium abundance and the mixing-length parameter of the models in the usual way for standard stellar models. Low-l g-mode oscillation periods were calculated for each of the models and compared to the claimed observation of the solar g-mode oscillation spectrum by Hill & Gu (1990). If one accepts Hill & Gu's claims, then within the uncertainties of the physics of the solar model calculation, our models rule out all but (delta G/GH) less than approximately 0.05. In other words, we conclude that G could not have varied by more than 2% over the past 4.5 Gyr, the lifetime of the present-day Sun. This result lends independent support to the validity of the standard solar model.
Sensitivity of solar g-modes to varying G cosmologies
NASA Technical Reports Server (NTRS)
Guenther, D. B.; Sills, Ken; Demarque, Pierre; Krauss, Lawrence M.
1995-01-01
The sensitivity of the solar g-mode oscillation spectrum to variability in the universal gravitational constant G is described. Solar models in varying G cosmologies were constructed by evolving a zero-age main-sequence stellar model to the Sun's current age, while allowing the value of G to change according to the power law G(t) proportional to t(exp -beta), where Beta approximately equals delta G/GH and H is the Hubble constant. All solar models were constrained to the observed luminosity and radius at the current age of the Sun by adjusting the helium abundance and the mixing-length parameter of the models in the usual way for standard stellar models. Low-l g-mode oscillation periods were calculated for each of the models and compared to the claimed observation of the solar g-mode oscillation spectrum by Hill & Gu (1990). If one accepts Hill & Gu's claims, then within the uncertainties of the physics of the solar model calculation, our models rule out all but (delta G/GH) less than approximately 0.05. In other words, we conclude that G could not have varied by more than 2% over the past 4.5 Gyr, the lifetime of the present-day Sun. This result lends independent support to the validity of the standard solar model.
Sensitivity of solar g-modes to varying G cosmologies
NASA Astrophysics Data System (ADS)
Guenther, D. B.; Sills, Ken; Demarque, Pierre; Krauss, Lawrence M.
1995-05-01
The sensitivity of the solar g-mode oscillation spectrum to variability in the universal gravitational constant G is described. Solar models in varying G cosmologies were constructed by evolving a zero-age main-sequence stellar model to the Sun's current age, while allowing the value of G to change according to the power law G(t) proportional to t-beta, where Beta approximately equals delta G/GH and H is the Hubble constant. All solar models were constrained to the observed luminosity and radius at the current age of the Sun by adjusting the helium abundance and the mixing-length parameter of the models in the usual way for standard stellar models. Low-l g-mode oscillation periods were calculated for each of the models and compared to the claimed observation of the solar g-mode oscillation spectrum by Hill & Gu (1990). If one accepts Hill & Gu's claims, then within the uncertainties of the physics of the solar model calculation, our models rule out all but (delta G/GH) less than approximately 0.05. In other words, we conclude that G could not have varied by more than 2% over the past 4.5 Gyr, the lifetime of the present-day Sun. This result lends independent support to the validity of the standard solar model.
Investigations into ultraviolet matrix-assisted laser desorption
Heise, T.W.
1993-07-01
Matrix-assisted laser desorption (MALD) is a technique for converting large biomolecules into gas phase ions. Some characteristics of the commonly used uv matrices are determined. Solubilities in methanol range from 0.1 to 0.5 M. Solid phase absorption spectra are found to be similar to solution, but slightly red-shifted. Acoustic and quartz crystal microbalance signals are investigated as possible means of uv-MALD quantitation. Evidence for the existence of desorption thresholds is presented. Threshold values are determined to be in the range of 2 to 3 MW/cm{sup 2}. A transient imaging technique based on laser-excited fluorescence for monitoring MALD plumes is described. Sensitivity is well within the levels required for studying matrix-assisted laser desorption, where analyte concentrations are significantly lower than those in conventional laser desorption. Results showing the effect of film morphology, particularly film thickness, on plume dynamics are presented. In particular, MALD plumes from thicker films tend to exhibit higher axial velocities. Fluorescent labeling of protein and of DNA is used to allow imaging of their uv-MALD generated plumes. Integrated concentrations are available with respect to time, making it possible to assess the rate of fragmentation. The spatial and temporal distributions are important for the design of secondary ionization schemes to enhance ion yields and for the optimization of ion collection in time-of-flight MS instruments to maximize resolution. Such information could also provide insight into whether ionization is closely associated with the desorption step or whether it is a result of subsequent collisions with the matrix gas (e.g., proton transfer). Although the present study involves plumes in a normal atmosphere, adaptation to measurements in vacuum (e.g., inside a mass spectrometer) should be straightforward.
Genetic Relationships Between Chondrules, Rims and Matrix
NASA Technical Reports Server (NTRS)
Huss, G. R.; Alexander, C. M. OD.; Palme, H.; Bland, P. A.; Wasson, J. T.
2004-01-01
The most primitive chondrites are composed of chondrules and chondrule fragments, various types of inclusions, discrete mineral grains, metal, sulfides, and fine-grained materials that occur as interchondrule matrix and as chondrule/inclusion rims. Understanding how these components are related is essential for understanding how chondrites and their constituents formed and were processed in the solar nebula. For example, were the first generations of chondrules formed by melting of matrix or matrix precursors? Did chondrule formation result in appreciable transfer of chondrule material into the matrix? Here, we consider three types of data: 1) compositional data for bulk chondrites and matrix, 2) mineralogical and textural information, and 3) the abundances and characteristics of presolar materials that reside in the matrix and rims. We use these data to evaluate the roles of evaporation and condensation, chondrule formation, mixing of different nebular components, and secondary processing both in the nebula and on the parent bodies. Our goal is to identify the things that are reasonably well established and to point out the areas that need additional work.
NASA Astrophysics Data System (ADS)
Smirnov, Andrey
2016-08-01
A torus action on a symplectic variety allows one to construct solutions to the quantum Yang-Baxter equations ( R-matrices). For a torus action on cotangent bundles over flag varieties the resulting R-matrices are the standard rational solutions of the Yang-Baxter equation, well known in the theory of quantum integrable systems. The torus action on the instanton moduli space leads to more complicated R-matrices, depending additionally on two equivariant parameters t 1 and t 2. In this paper we derive an explicit expression for the R-matrix associated with the instanton moduli space. We study its matrix elements and its Taylor expansion in the powers of the spectral parameter. Certain matrix elements of this R-matrix give a generating function for the characteristic classes of tautological bundles over the Hilbert schemes in terms of the bosonic cut-and-join operators. In particular we rederive from the R-matrix the well known Lehn's formula for the first Chern class. We explicitly compute the first several coefficients for the power series expansion of the R-matrix in the spectral parameter. These coefficients are represented by simple contour integrals of some symmetrized bosonic fields.
Matrix method for acoustic levitation simulation.
Andrade, Marco A B; Perez, Nicolas; Buiochi, Flavio; Adamowski, Julio C
2011-08-01
A matrix method is presented for simulating acoustic levitators. A typical acoustic levitator consists of an ultrasonic transducer and a reflector. The matrix method is used to determine the potential for acoustic radiation force that acts on a small sphere in the standing wave field produced by the levitator. The method is based on the Rayleigh integral and it takes into account the multiple reflections that occur between the transducer and the reflector. The potential for acoustic radiation force obtained by the matrix method is validated by comparing the matrix method results with those obtained by the finite element method when using an axisymmetric model of a single-axis acoustic levitator. After validation, the method is applied in the simulation of a noncontact manipulation system consisting of two 37.9-kHz Langevin-type transducers and a plane reflector. The manipulation system allows control of the horizontal position of a small levitated sphere from -6 mm to 6 mm, which is done by changing the phase difference between the two transducers. The horizontal position of the sphere predicted by the matrix method agrees with the horizontal positions measured experimentally with a charge-coupled device camera. The main advantage of the matrix method is that it allows simulation of non-symmetric acoustic levitators without requiring much computational effort.
Pseudomonas biofilm matrix composition and niche biology
Mann, Ethan E.; Wozniak, Daniel J.
2014-01-01
Biofilms are a predominant form of growth for bacteria in the environment and in the clinic. Critical for biofilm development are adherence, proliferation, and dispersion phases. Each of these stages includes reinforcement by, or modulation of, the extracellular matrix. Pseudomonas aeruginosa has been a model organism for the study of biofilm formation. Additionally, other Pseudomonas species utilize biofilm formation during plant colonization and environmental persistence. Pseudomonads produce several biofilm matrix molecules, including polysaccharides, nucleic acids, and proteins. Accessory matrix components shown to aid biofilm formation and adaptability under varying conditions are also produced by pseudomonads. Adaptation facilitated by biofilm formation allows for selection of genetic variants with unique and distinguishable colony morphology. Examples include rugose small-colony variants and wrinkly spreaders (WS), which over produce Psl/Pel or cellulose, respectively, and mucoid bacteria that over produce alginate. The well-documented emergence of these variants suggests that pseudomonads take advantage of matrix-building subpopulations conferring specific benefits for the entire population. This review will focus on various polysaccharides as well as additional Pseudomonas biofilm matrix components. Discussions will center on structure–function relationships, regulation, and the role of individual matrix molecules in niche biology. PMID:22212072
Interfaces between a fibre and its matrix
NASA Astrophysics Data System (ADS)
Lilholt, H.; Sørensen, B. F.
2017-07-01
The interface between a fibre and its matrix represents an important element in the characterization and exploitation of composite materials. Both theoretical models and analyses of experimental data have been presented in the literature since modern composite were developed and many experiments have been performed. A large volume of results for a wide range of composite systems exists, but rather little comparison and potential consistency have been reached for fibres and/or for matrices. Recently a materials mechanics approach has been presented to describe the interface by three parameters, the interfacial energy [J/m2], the interfacial frictional shear stress [MPa] and the mismatch strain [-] between fibre and matrix. The model has been used for the different modes of fibre pull-out and fibre fragmentation. In this paper it is demonstrated that the governing equations for the experimental parameters (applied load, debond length and relative fibre/matrix displacement) are rather similar for these test modes. A simplified analysis allows the direct determination of the three interface parameters from two plots for the experimental data. The complete analysis is demonstrated for steel fibres in polyester matrix. The analysis of existing experimental literature data is demonstrated for steel fibres in epoxy matrix and for tungsten wires in copper matrix. These latter incomplete analyses show that some results can be obtained even if all three experimental parameters are not recorded.
Temperature dependent nonlinear metal matrix laminae behavior
NASA Technical Reports Server (NTRS)
Barrett, D. J.; Buesking, K. W.
1986-01-01
An analytical method is described for computing the nonlinear thermal and mechanical response of laminated plates. The material model focuses upon the behavior of metal matrix materials by relating the nonlinear composite response to plasticity effects in the matrix. The foundation of the analysis is the unidirectional material model which is used to compute the instantaneous properties of the lamina based upon the properties of the fibers and matrix. The unidirectional model assumes that the fibers properties are constant with temperature and assumes that the matrix can be modelled as a temperature dependent, bilinear, kinematically hardening material. An incremental approach is used to compute average stresses in the fibers and matrix caused by arbitrary mechanical and thermal loads. The layer model is incorporated in an incremental laminated plate theory to compute the nonlinear response of laminated metal matrix composites of general orientation and stacking sequence. The report includes comparisons of the method with other analytical approaches and compares theoretical calculations with measured experimental material behavior. A section is included which describes the limitations of the material model.
Sterile Neutrinos in a 6x6 Matrix
NASA Astrophysics Data System (ADS)
Goldman, T.; McKellar, B. H. J.; Stephenson, G. J., Jr.
2006-10-01
An early study of neutrino mixing within the see-saw framework considered random mass matrices in what is now known as the sterile sector[1]. The mixing angles in the lepton sector were found to be closely distributed about the CKM angles that were assumed. In that work, rank 3 was assumed for the weak isospin zero Majorana mass matrix in the sterile neutrino sector. We report here on the character of new results using a reduced rank (``singular'') sterile matrix. We find that an additional flavor misalignment in the sterile sector can produce several interesting effects, including: 1) mass eigenstates that lead to very large flavor mixing among active neutrinos, and 2) small values for the 1-3 mixing angle parameter[2]. We also discuss the limits that current observations place on the mass scale of light sterile neutrinos in this model. [1]T. Goldman and G. J. Stephenson, Jr., ``How Large Are the Neutrino Mixing Angles?'' Phys. Rev. D 24, 236 (1981). [2]G. J. Stephenson, Jr. , T. Goldman, B. H. J. McKellar and M. Garbutt, ``Large Mixing from Small: Pseudo-Dirac Neutrinos and the Singular Seesaw,'' Int. J.Mod.Phys.A20 (2005) 6373; [hep-ph/0404015].
Corn stalk as matrix in decomposting toilet for treating urine and feces
NASA Astrophysics Data System (ADS)
Sintawardani, N.; Nilawati, D.; Astuti, J. T.
2017-03-01
Bio-Toilet technology (BT) which is appropriate for the habits of Indonesian people has been studied and developed. BT is a dry toilet technology commonly uses ligno-cellulosic waste materials as matrix to facilitate the growth of natural microbes. In aerobic condition, microbes degrade feces and urine. Mineral as the leftover of feces and urine, such as nitrogen (N), phosphorus (P), and potassium (K) remain in the rest of matrix waste. After certain period. matrix can be harvested and used as soil conditioner. BT uses much less water, mobile, and very useful to be applied in areas where water availability is limited. BT type with different capacities, user amounts and mixing systems has been developed using sawdust for matrix. Since corn stalk is categorized as useless and priceless waste, its application in BT is challenging. Performance of BT with corn stalk as matrix to degrade feces and urine of carnivore imitating the human waste was observed. BT M-15 manual mixing type with paddle was filled with chopped corn stalk as much as 45% of total volume. This BT was designed for 15 person as users per day if 80% reactor volume was filled with ligno-cellulosic matrix. It is assumed that 150 g of feces are discharged once per person/day and 1000 mL of urine 6-8 times per day. Start up process was made in the beginning to initialize the needed microbes in the reactor (matrix). The discharge of feces and urine were increased slowly and gradually the users were increased from 1 to 4 users per day. Performance of BT was indicated by the change in the pile that showed by moisture content, temperature and pH. C/N ratio in matrix decreased significantly from 43 to 17. This result showed that the corn stalk could be used as matrix in BT.
Ionic liquids as matrixes for matrix-assisted laser desorption/ionization mass spectrometry.
Armstrong, D W; Zhang, L K; He, L; Gross, M L
2001-08-01
Room-temperature ionic liquids are useful as solvents for organic synthesis, electrochemical studies, and separations. We wished to examine whether their high solubalizing power, negligible vapor pressure, and broad liquid temperature range are advantageous if they are used as matrixes for UV-MALDI. Several different ionic matrixes were synthesized and tested, using peptides, proteins, and poly(ethylene glycol) (PEG-2000). All ionic liquids tested have excellent solubilizing properties and vacuum stability compared to other commonly used liquid and solid matrixes. However, they varied widely in their ability to produce analyte gas-phase ions. Certain ionic matrixes, however, produce homogeneous solutions of greater vacuum stability, higher ion peak intensity, and equivalent or lower detection limits than currently used solid matrixes. Clearly, ionic liquids and their more amorphous solid analogues merit further investigation as MALDI matrixes.
Modeling the formation of cell-matrix adhesions on a single 3D matrix fiber.
Escribano, J; Sánchez, M T; García-Aznar, J M
2015-11-07
Cell-matrix adhesions are crucial in different biological processes like tissue morphogenesis, cell motility, and extracellular matrix remodeling. These interactions that link cell cytoskeleton and matrix fibers are built through protein clutches, generally known as adhesion complexes. The adhesion formation process has been deeply studied in two-dimensional (2D) cases; however, the knowledge is limited for three-dimensional (3D) cases. In this work, we simulate different local extracellular matrix properties in order to unravel the fundamental mechanisms that regulate the formation of cell-matrix adhesions in 3D. We aim to study the mechanical interaction of these biological structures through a three dimensional discrete approach, reproducing the transmission pattern force between the cytoskeleton and a single extracellular matrix fiber. This numerical model provides a discrete analysis of the proteins involved including spatial distribution, interaction between them, and study of the different phenomena, such as protein clutches unbinding or protein unfolding.
Hsieh, Cheng-Hsilin; Tam, Ming F
2006-03-01
We report a method to detect the presence of dimethylarginines on proteins. Peptides with dimethylarginines were hydrolyzed in acid. The hydrolysates were subjected to matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometric analysis using a mixture of alpha-cyano-4-hydroxycinnamic acid and nitrocellulose as matrix. Both asymmetric omega-N(G),N(G)-dimethylarginine and symmetric omega-N(G),N(G')-dimethylarginine give a clear signal at m/z 203. Recombinant Sbp1p modified by Hmt1p in vivo were isolated by affinity chromatography followed by electrophoresis on a polyacrylamide gel and subjected to acid hydrolysis. MALDI-TOF analysis of the acid hydrolysates confirmed the presence of dimethylarginines. The detection limit of the method is estimated at approximately 1pmol of protein.
Riemannian symmetric superspaces and their origin in random-matrix theory
Zirnbauer, M.R.
1996-10-01
Gaussian random-matrix ensembles defined over the tangent spaces of the large families of Cartan{close_quote}s symmetric spaces are considered. Such ensembles play a central role in mesoscopic physics, as they describe the universal ergodic limit of disordered and chaotic single-particle systems. The generating function for the spectral correlations of each ensemble is reduced to an integral over a Riemannian symmetric superspace in the limit of large matrix dimension. Such a space is defined as a pair ({ital G}/{ital H},{ital M}{sub {ital r}}), where {ital G}/{ital H} is a complex-analytic graded manifold homogeneous with respect to the action of a complex Lie supergroup {ital G}, and {ital M}{sub {ital r}} is a maximal Riemannian submanifold of the support of {ital G}/{ital H}. {copyright} {ital 1996 American Institute of Physics.}
NASA Astrophysics Data System (ADS)
Allwood, D. A.; Dyer, P. E.
2000-11-01
Fundamental photophysical parameters have been determined for several molecules that are commonly used as matrices, e.g. ferulic acid, within matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. Fluorescence quantum efficiencies ( φqe), singlet decay rates ( kl), vibrationless ground-singlet transition energies and average fluorescence wavelengths have been obtained from solid and solution samples by quantitative optical measurements. This new data will assist in modelling calculations of MALDI processes and in highlighting desirable characteristics of MALDI matrices. φqe may be as high as 0.59 whilst the radiative decay rate ( kf) appears to be within the (0.8-4)×10 8 s -1 range. Interestingly, α-cyano-4-hydroxycinnamic acid (α-CHC) has a very low φqe and fast non-radiative decay rate which would imply a rapid and efficient thermalisation of electronic excitation. This is in keeping with observations that α-CHC exhibits low threshold fluences for ion detection and the low fluences at which α-CHC tends to fragment.
Optical matrix-matrix multiplication method demonstrated by the use of a multifocus hololens.
Liang, Y Z; Liu, H K
1984-08-01
A method of optical matrix-matrix multiplication is presented. The feasibility of the method is also experimentally demonstrated by the use of a dichromated-gelatin multifocus holographic lens (hololens). With the specific values of matrices chosen, the average percentage error between the theoretical and experimental data of the elements of the output matrix of the multiplication of some specific pairs of 3 x 3 matrices is 0.4%, which corresponds to an 8-bit accuracy.
Optical matrix-matrix multiplication method demonstrated by the use of a multifocus hololens
NASA Technical Reports Server (NTRS)
Liu, H. K.; Liang, Y.-Z.
1984-01-01
A method of optical matrix-matrix multiplication is presented. The feasibility of the method is also experimentally demonstrated by the use of a dichromated-gelatin multifocus holographic lens (hololens). With the specific values of matrices chosen, the average percentage error between the theoretical and experimental data of the elements of the output matrix of the multiplication of some specific pairs of 3 x 3 matrices is 0.4 percent, which corresponds to an 8-bit accuracy.
Method of producing a hybrid matrix fiber composite
Deteresa, Steven J.; Lyon, Richard E.; Groves, Scott E.
2006-03-28
Hybrid matrix fiber composites having enhanced compressive performance as well as enhanced stiffness, toughness and durability suitable for compression-critical applications. The methods for producing the fiber composites using matrix hybridization. The hybrid matrix fiber composites comprised of two chemically or physically bonded matrix materials, whereas the first matrix materials are used to impregnate multi-filament fibers formed into ribbons and the second matrix material is placed around and between the fiber ribbons that are impregnated with the first matrix material and both matrix materials are cured and solidified.
NASA Astrophysics Data System (ADS)
Longbiao, Li
2015-12-01
The matrix multicracking evolution of cross-ply ceramic-matrix composites (CMCs) has been investigated using energy balance approach. The multicracking of cross-ply CMCs was classified into five modes, i.e., (1) mode 1: transverse multicracking; (2) mode 2: transverse multicracking and matrix multicracking with perfect fiber/matrix interface bonding; (3) mode 3: transverse multicracking and matrix multicracking with fiber/matrix interface debonding; (4) mode 4: matrix multicracking with perfect fiber/matrix interface bonding; and (5) mode 5: matrix multicracking with fiber/matrix interface debonding. The stress distributions of four cracking modes, i.e., mode 1, mode 2, mode 3 and mode 5, are analysed using shear-lag model. The matrix multicracking evolution of mode 1, mode 2, mode 3 and mode 5, has been determined using energy balance approach. The effects of ply thickness and fiber volume fraction on matrix multicracking evolution of cross-ply CMCs have been investigated.
INTEGRATED COI S200 - Hi-NiCalon FIBER WITH AN S200 MATRIX (POLYMER MATRIX COMPOSITE - PMC) / AETB 1
NASA Technical Reports Server (NTRS)
2003-01-01
INTEGRATED COI S200 - Hi-NiCalon FIBER WITH AN S200 MATRIX (POLYMER MATRIX COMPOSITE - PMC) / AETB 16 (FOAM CORE) / CARBON REINFORCED CYANOESTER (CERAMIC MATRIX COMPOSITE - CMC) HOT STRUCTURE, PANEL 884-1: SAMPLE 1
INTEGRATED COI S200 - Hi-NiCalon FIBER WITH AN S200 MATRIX (POLYMER MATRIX COMPOSITE - PMC) / AETB 1
NASA Technical Reports Server (NTRS)
2003-01-01
INTEGRATED COI S200 - Hi-NiCalon FIBER WITH AN S200 MATRIX (POLYMER MATRIX COMPOSITE - PMC) / AETB 16 (FOAM CORE) / CARBON REINFORCED CYANOESTER (CERAMIC MATRIX COMPOSITE - CMC) HOT STRUCTURE, PANEL 884-1: SAMPLE 3
NASA Technical Reports Server (NTRS)
Johnson, W. S.
1988-01-01
Continuous fiber reinforced metal matrix composites (MMC) are projected for use in high temperature, stiffness critical parts that will be subjected to cyclic loadings. Depending on the relative fatigue behavior of the fiber and matrix, and the interface properties, the failure modes of MMC can be grouped into four catagories: (1) matrix dominated, (2) fiber dominated, (3) self-similar damage growth, and (4) fiber/matrix interfacial failures. These four types of damage are discussed and illustrated by examples. The emphasis is on the fatigue of unnotched laminates.
Method of forming a ceramic matrix composite and a ceramic matrix component
de Diego, Peter; Zhang, James
2017-05-30
A method of forming a ceramic matrix composite component includes providing a formed ceramic member having a cavity, filling at least a portion of the cavity with a ceramic foam. The ceramic foam is deposited on a barrier layer covering at least one internal passage of the cavity. The method includes processing the formed ceramic member and ceramic foam to obtain a ceramic matrix composite component. Also provided is a method of forming a ceramic matrix composite blade and a ceramic matrix composite component.
On the Differentiation Matrix for Daubechies-Based Wavelets on an Interval
1993-12-01
projection matrix D. If we let .’ denote the vector of the scaling function coefficients sk, for k = 0, ... , d - 1, then 1) maps from the scaling...80, NASA CR-191557. [8] Y. Meyer, "Ondelettes sur I’nteralle", Revista Matematica Iberoamericana 7, 1992, pp 115-133. [9] G. Strang, "Wavelets and
Transmission Electron Microscopy of the Matrix Minerals in the Tagish Lake Carbonaceous Chondrite
NASA Technical Reports Server (NTRS)
Mikouchi, T.; Kasama, T.; Zolensky, M. E.; Tachikawa, O.
2001-01-01
We studied the Tagish Lake matrix minerals by TEM. The result shows similarities to CIs (and CRs) and differences from CMs, but its heterogeneity (e.g., carbonate abundance, saponite/serpentine ratio) suggests its complex history. Additional information is contained in the original extended abstract.
EPA Positive Matrix Factorization (PMF) 5.0 Fundamentals and User Guide
PMF is a multivariate factor analysis tool that decomposes a matrix of speciated sample data into two matrices: factor contributions (G) and factor profiles (F). These factor profiles need to be interpreted by the user to identify the source types that may be contributing to the ...
Transmission Electron Microscopy of the Matrix Minerals in the Tagish Lake Carbonaceous Chondrite
NASA Technical Reports Server (NTRS)
Mikouchi, T.; Kasama, T.; Zolensky, M. E.; Tachikawa, O.
2001-01-01
We studied the Tagish Lake matrix minerals by TEM. The result shows similarities to CIs (and CRs) and differences from CMs, but its heterogeneity (e.g., carbonate abundance, saponite/serpentine ratio) suggests its complex history. Additional information is contained in the original extended abstract.