de Abreu, J.R.F.; de Launay, D.; Sanders, M.E.; Grabiec, A.M.; van de Sande, M.G.; Tak, P.P.; Reedquist, K.A.
2009-01-01
Introduction Fibroblast-like synoviocytes (FLS) from rheumatoid arthritis ( RA) patients share many similarities with transformed cancer cells, including spontaneous production of matrix metalloproteinases ( MMPs). Altered or chronic activation of proto-oncogenic Ras family GTPases is thought to
Jin, Shan-Xue; Arai, Junko; Tian, Xuejun; Kumar-Singh, Rajendra; Feig, Larry A
2013-07-26
RAS-GRF1 is a guanine nucleotide exchange factor with the ability to activate RAS and RAC GTPases in response to elevated calcium levels. We previously showed that beginning at 1 month of age, RAS-GRF1 mediates NMDA-type glutamate receptor (NMDAR)-induction of long term depression in the CA1 region of the hippocampus of mice. Here we show that beginning at 2 months of age, when mice first acquire the ability to discriminate between closely related contexts, RAS-GRF1 begins to contribute to the induction of long term potentiation (LTP) in the CA1 hippocampus by mediating the action of calcium-permeable, AMPA-type glutamate receptors (CP-AMPARs). Surprisingly, LTP induction by CP-AMPARs through RAS-GRF1 occurs via activation of p38 MAP kinase rather than ERK MAP kinase, which has more frequently been linked to LTP. Moreover, contextual discrimination is blocked by knockdown of Ras-Grf1 expression specifically in the CA1 hippocampus, infusion of a p38 MAP kinase inhibitor into the CA1 hippocampus, or the injection of an inhibitor of CP-AMPARs. These findings implicate the CA1 hippocampus in the developmentally dependent capacity to distinguish closely related contexts through the appearance of a novel LTP-supporting signaling pathway.
No evidence for a parent of origin specific differentially methylated region linked to RASGRF1
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Punita ePitamber
2012-03-01
Full Text Available Abstract Imprinted genes are expressed from one parental allele in a parent-of-origin manner. This mono-allelic behavior is regulated by allele-specific DNA methylation that is confined to differentially methylated regions (DMRs. To date there are over 80 known human imprinted genes of which only three are known to have paternally methylated DMRs. In mice there exists an additional paternally methylated DMR associated with Rasgrf1. The Rasgrf1 gene forms part of the MAPK signaling pathway and plays a role in long-term memory formation and growth control. The presence of a RASGRF1-associated DMR in humans and its methylation status has not been explored. The primary aim of this study was to determine whether the human RASGRF1 gene contains a DMR and whether this DMR is paternally methylated. Computational assessments were done to identify putative CTCF binding sites, CpG islands (CGIs that could serve as potential RASGRF1 DMRs and tandem repeats within or adjacent to these CGIs. The methylation status of three putative CGIs was assessed using quantitative pyrosequencing technology. None of the putative CTCF binding sites were found to occur in the predicted CGIs. The three putative CGIs linked to RASGRF1 did not display allele-specific methylation in blood DNA nor unique paternal methylation in sperm DNA. While one of the three CGIs was found to be hypomethylated in both blood DNA and sperm DNA, the other two were found to be hypermethylated. The tandem repeats that were identified were associated with only one of the putative CGIs. This CGI is located at the promoter region of RASGRF1 and was found to be hypomethylated both in the peripheral blood and in the sperm samples. The CGIs evaluated in this study did not fit the criteria of being a DMR. The human RASGRF1-associated CpG rich regions do not exhibit differential methylation in a parent-of-origin manner. However, expression studies would need to be performed to confirm the imprint status of
Rasgrf1 Imprinting Is Regulated by a CTCF-Dependent Methylation-Sensitive Enhancer Blocker
Yoon, Bongjune; Herman, Herry; Hu, Benjamin; Park, Yoon Jung; Lindroth, Anders; Bell, Adam; West, Adam G.; Chang, Yanjie; Stablewski, Aimee; Piel, Jessica C.; Loukinov, Dmitri I.; Lobanenkov, Victor V.; Soloway, Paul D.
2005-01-01
Imprinted methylation of the paternal Rasgrf1 allele in mice occurs at a differentially methylated domain (DMD) 30 kbp 5′ of the promoter. A repeated sequence 3′ of the DMD regulates imprinted methylation, which is required for imprinted expression. Here we identify the mechanism by which methylation controls imprinting. The DMD is an enhancer blocker that binds CTCF in a methylation-sensitive manner. CTCF bound to the unmethylated maternal allele silences expression. CTCF binding to the paternal allele is prevented by repeat-mediated methylation, allowing expression. Optimal in vitro enhancer-blocking activity requires CTCF binding sites. The enhancer blocker can be bypassed in vivo and imprinting abolished by placing an extra enhancer proximal to the promoter. Together, the repeats and the DMD constitute a binary switch that regulates Rasgrf1 imprinting. PMID:16314537
Genetic variation of the RASGRF1 regulatory region affects human hippocampus-dependent memory
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Adriana eBarman
2014-04-01
Full Text Available The guanine nucleotide exchange factor RASGRF1 is an important regulator of intracellular signaling and neural plasticity in the brain. RASGRF1-deficient mice exhibit a complex phenotype with learning deficits and ocular abnormalities. Also in humans, a genome-wide association study has identified the single nucleotide polymorphism (SNP rs8027411 in the putative transcription regulatory region of RASGRF1 as a risk variant of myopia. Here we aimed to assess whether, in line with the RASGRF1 knockout mouse phenotype, rs8027411 might also be associated with human memory function. We performed computer-based neuropsychological learning experiments in two independent cohorts of young, healthy participants. Tests included the Verbal Learning and Memory Test (VLMT and the logical memory section of the Wechsler Memory Scale (WMS. Two sub-cohorts additionally participated in functional magnetic resonance imaging (fMRI studies of hippocampus function. 119 participants performed a novelty encoding task that had previously been shown to engage the hippocampus, and 63 subjects participated in a reward-related memory encoding study. RASGRF1 rs8027411 genotype was indeed associated with memory performance in an allele dosage-dependent manner, with carriers of the T allele (i.e. the myopia risk allele showing better memory performance in the early encoding phase of the VLMT and in the recall phase of the WMS logical memory section. In fMRI, T allele carriers exhibited increased hippocampal activation during presentation of novel images and during encoding of pictures associated with monetary reward. Taken together, our results provide evidence for a role of the RASGRF1 gene locus in hippocampus-dependent memory and, along with the previous association with myopia, point towards pleitropic effects of RASGRF1 genetic variations on complex neural function in humans.
Antagonism between DNA and H3K27 methylation at the imprinted Rasgrf1 locus
DEFF Research Database (Denmark)
Lindroth, Anders M; Park, Yoon Jung; McLean, Chelsea M;
2008-01-01
At the imprinted Rasgrf1 locus in mouse, a cis-acting sequence controls DNA methylation at a differentially methylated domain (DMD). While characterizing epigenetic marks over the DMD, we observed that DNA and H3K27 trimethylation are mutually exclusive, with DNA and H3K27 methylation limited...... DMD inappropriately acquired DNA methylation; and by analyzing materials from cells and embryos lacking SUZ12 and YY1. SUZ12 is part of the PRC2 complex, which is needed for placing H3K27me3, and YY1 recruits PRC2 to sites of action. Results from each experimental system consistently demonstrated...
Drake, Nadia M.; Park, Yoon Jung; Shirali, Aditya S.; Cleland, Thomas A.
2010-01-01
Rasgrf1 is imprinted and expressed preferentially from the paternal allele in neonatal mouse brain. At weaning, expression becomes biallelic. Using a mouse model, we assayed the effects of perturbing imprinted Rasgrf1 expression in mice with the following imprinted expression patterns: monoallelic paternal (wild type), monoallelic maternal (maternal only), biallelic (both alleles transcribed), and null (neither allele transcribed). All genotypes exhibit biallelic expression around weaning. Consequences of this transient imprinting perturbation are manifested as overall size differences that correspond to the amount of neonatal Rasgrf1 expressed and are persistent, extending into adulthood. Biallelic mice are the largest and overexpress Rasgrf1 relative to wild-type mice, null mice are the smallest and underexpress Rasgrf1 as neonates, and the two monoallelically expressing genotypes are intermediate and indistinguishable from one another, in both size and Rasgrf1 expression level. Importantly, these data support one of the key underlying assumptions of the “conflict hypothesis” that describes the evolution of genomic imprinting in mammals and supposes that equivalent amounts of imprinted gene expression produce equivalent phenotypes, regardless of which parental allele is transcribed. Concordant with the difference in overall body size, we identify differences in IGF-1 levels, both in serum protein and as liver transcript, and identify additional differential expression of components upstream of IGF-1 release in the GH/IGF-1 axis. These data suggest that imprinted Rasgrf1 expression affects GH/IGF-1 axis function, and that the consequences of Rasgrf1 inputs to this axis persist beyond the time period when expression is restricted via epigenetic mechanisms, suggesting that proper neonatal Rasgrf1 expression levels are critical for development. PMID:19513790
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Raffaele ed'Isa
2011-12-01
Full Text Available Ras-GRF1 is a neuronal specific guanine exchange factor that, once activated by both ionotropic and metabotropic neurotransmitter receptors, can stimulate Ras proteins, leading to long-term phosphorylation of downstream signaling. The two available reports on the behavior of two independently generated Ras-GRF1 deficient mouse lines provide contrasting evidence on the role of Ras-GRF1 in spatial memory and contextual fear conditioning. These discrepancies may be due to the distinct alterations introduced in the mouse genome by gene targeting in the two lines that could differentially affect expression of nearby genes located in the imprinted region containing the Ras-grf1 locus. In order to determine the real contribution of Ras-GRF1 to spatial memory we compared in Morris Water Maze learning the Brambilla’s mice with a third mouse line (GENA53 in which a nonsense mutation was introduced in the Ras-GRF1 coding region without additional changes in the genome and we found that memory in this task is normal. Also, we measured both contextual and cued fear conditioning, which were previously reported to be affected in the Brambilla’s mice, and we confirmed that contextual learning but not cued conditioning is impaired in both mouse lines. In addition, we also tested both lines for the first time in conditioned place aversion in the Intellicage, an ecological and remotely controlled behavioral test, and we observed normal learning. Finally, based on previous reports of other mutant lines suggesting that Ras-GRF1 may control body weight, we also measured this non-cognitive phenotype and we confirmed that both Ras-GRF1 deficient mutants are smaller than their control littermates. In conclusion, we demonstrate that Ras-GRF1 has no unique role in spatial memory while its function in contextual fear conditioning is likely to be due not only to its involvement in amygdalar functions but possibly to some distinct hippocampal connections specific to contextual learning.
Fernández-Medarde, A; Porteros, A; de las Rivas, J; Núñez, A; Fuster, J J; Santos, E
2007-04-25
We used manual macrodissection or laser capture microdissection (LCM) to isolate tissue sections of the hippocampus area of Ras-GRF1 wild type and knockout mice brains, and analyzed their transcriptional patterns using commercial oligonucleotide microarrays. Comparison between the transcriptomes of macrodissected and microdissected samples showed that the LCM samples allowed detection of significantly higher numbers of differentially expressed genes, with higher statistical rates of significance. These results validate LCM as a reliable technique for in vivo genomic studies in the brain hippocampus, where contamination by surrounding areas (not expressing Ras-GRF1) increases background noise and impairs identification of differentially expressed genes. Comparison between wild type and knockout LCM hippocampus samples revealed that Ras-GRF1 elimination caused significant gene expression changes, mostly affecting signal transduction and related neural processes. The list of 36 most differentially expressed genes included loci concerned mainly with Ras/G protein signaling and cytoskeletal organization (i.e. 14-3-3gamma/zeta, Kcnj6, Clasp2) or related, cross-talking pathways (i.e. jag2, decorin, strap). Consistent with the phenotypes shown by Ras-GRF1 knockout mice, many of these differentially expressed genes play functional roles in processes such as sensory development and function (i.e. Sptlc1, antiquitin, jag2) and/or neurological development/neurodegeneration processes affecting memory and learning. Indeed, potential links to neurodegenerative diseases such as Alzheimer disease (AD) or Creutzfeldt-Jacobs disease (CJD), have been reported for a number of differentially expressed genes identified in this study (Ptma, Aebp2, Clasp2, Hebp1, 14-3-3gamma/zeta, Csnk1delta, etc.). These data, together with the previously described role of IRS and insulin (known Ras-GRF1 activators) in AD, warrant further investigation of a potential functional link of Ras-GRF1 to neurodegenerative processes.
Behaviour Study of The Ras-GRF1 Gene knockout Mice%Ras-GRF1基因敲除小鼠的行为学研究
Institute of Scientific and Technical Information of China (English)
段巍鹤; 郑宏亮; 陆美林; 万家余; 何秀霞
2015-01-01
The Ras genes widely exist in nature, Ras-GRF1 proteins in cell signal transduction, cell differentiation and growth play a very important role. Previous researchs have shown that the Ras genes are closely associated with signal-ing pathways and learning and memory function. This research was study to companed the differences between the gene knockout Ras-GRF1 and will rats on learning and memory by the behavior experiments. It was found that Ras-GRF1 knockout mice learning memory ability weak in wild type mice by Morris water maze,etc.%Ras基因广泛存在于自然界中，其控制的Ras-GRF1蛋白在细胞信号传导，在细胞分化与生长过程中起着极其重要的作用。已有研究表明，Ras基因与信号通路和学习记忆功能密切相关。本实验利用行为学研究敲除Ras-GRF1基因的小鼠在学习记忆上与野生老鼠的差异，通过Morris水迷宫等实验发现Ras-GRF1基因敲除小鼠的学习记忆能力弱于野生型小鼠。
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Jaysen Gregory Knezovich
2012-02-01
Full Text Available Imprinted loci play a critical role in fetal development. Their expression is often regulated by CTCF protein binding at imprinting control regions (ICRs. Parental alcohol exposure has been shown to reduce global DNA methylation in the developing mouse fetus. This study explored the effect of preconception paternal alcohol exposure on DNA methylation at two paternally methylated ICRs (H19 and Rasgrf1 in the sperm of exposed males and somatic DNA of sired offspring. Significant reductions at the H19 CTCF 1 (p=0.0027 and CTCF 2 (p=0.0009 binding sites were observed in the offspring of ethanol-treated sires, which was significantly correlated with reduced weight at postnatal days 35 to 42 (p<0.05. As birth weight was unaffected and growth was only delayed during the postnatal weaning period, with subsequent re-convergence, we hypothesise that this may be the result of a mental deficit causing delayed establishment of independent feeding following weaning and would explain why this effect is transient. No difference in DNA methylation was observed in the sperm of alcohol-exposed males, indicating that the transmission of the epigenetic signal at conception is not due to altered methylation, but may be the result of an RNA-mediated mechanism or altered chromatin remodelling.
Matrix metalloproteinase 13-containing exosomes promote nasopharyngeal carcinoma metastasis.
You, Yiwen; Shan, Ying; Chen, Jing; Yue, Huijun; You, Bo; Shi, Si; Li, Xingyu; Cao, Xiaolei
2015-12-01
Nasopharyngeal cancer (NPC) is an endemic type of head and neck cancer with a high rate of cervical lymph node metastasis. Metastasis is the major cause of death in NPC patients. Increasing evidence indicates that exosomes play a pivotal role in promoting cancer metastasis by enhancing angiogenesis and ECM degradation. Matrix metalloproteinase 13 is an important kind of matrix proteinase that is often overexpressed in various tumors and increases the risk of metastasis. However, little is known about the potential role of MMP13-containing exosomes in NPC. In this study, we found that MMP13 was overexpressed in NPC cells and exosomes purified from conditioned medium (CM) as well as NPC patients' plasma. Transwell analysis revealed that MMP13-containing exosomes facilitated the metastasis of NPC cells. Furthermore, siRNA inhibited the effect of MMP13-containing exosomes on tumor cells metastasis as well as angiogenesis. The current findings provided novel insight into the vital role of MMP13-containing exosomes in NPC progression which might offer unique insights for potential therapeutic strategies for NPC progressions.
Hydrophilic polyurethane matrix promotes chondrogenesis of mesenchymal stem cells.
Nalluri, Sandeep M; Krishnan, G Rajesh; Cheah, Calvin; Arzumand, Ayesha; Yuan, Yuan; Richardson, Caley A; Yang, Shuying; Sarkar, Debanjan
2015-09-01
Segmental polyurethanes exhibit biphasic morphology and can control cell fate by providing distinct matrix guided signals to increase the chondrogenic potential of mesenchymal stem cells (MSCs). Polyethylene glycol (PEG) based hydrophilic polyurethanes can deliver differential signals to MSCs through their matrix phases where hard segments are cell-interactive domains and PEG based soft segments are minimally interactive with cells. These coordinated communications can modulate cell-matrix interactions to control cell shape and size for chondrogenesis. Biphasic character and hydrophilicity of polyurethanes with gel like architecture provide a synthetic matrix conducive for chondrogenesis of MSCs, as evidenced by deposition of cartilage-associated extracellular matrix. Compared to monophasic hydrogels, presence of cell interactive domains in hydrophilic polyurethanes gels can balance cell-cell and cell-matrix interactions. These results demonstrate the correlation between lineage commitment and the changes in cell shape, cell-matrix interaction, and cell-cell adhesion during chondrogenic differentiation which is regulated by polyurethane phase morphology, and thus, represent hydrophilic polyurethanes as promising synthetic matrices for cartilage regeneration.
Matrix metalloproteinase 13‐containing exosomes promote nasopharyngeal carcinoma metastasis
2015-01-01
Nasopharyngeal cancer (NPC) is an endemic type of head and neck cancer with a high rate of cervical lymph node metastasis. Metastasis is the major cause of death in NPC patients. Increasing evidence indicates that exosomes play a pivotal role in promoting cancer metastasis by enhancing angiogenesis and ECM degradation. Matrix metalloproteinase 13 is an important kind of matrix proteinase that is often overexpressed in various tumors and increases the risk of metastasis. However, little is kno...
Biotin-Avidin Based Universal Cell-Matrix Interaction for Promoting Three-Dimensional Cell Adhesion.
Dou, Xiao-Qiu; Zhang, Jia; Feng, Chuanliang
2015-09-23
To promote cell adhesion in three-dimensional (3D) extracellular matrix (ECM) is crucial for avoiding cell anoikis, which is one of the most important issues for fundamental cell biology. Herein, a biotin-avidin based universal cell-matrix interaction for different types of cells is developed in order to achieve the promoted adhesion in 3D ECM. For the purpose, biotinylated nanofibrous hydrogels are constructed by coassembling 1,4-benzyldicarboxamide (C2) based non-biotinylated and biotinylated supramolecular gelators. The used cells are modified by avidin (AV-cells) through biotinylating cells and then interacting with avidin. After in situ encapsulating AV-cells in the hydrogels, the adhered amount can be increased by tens of percent even with adding several percentages of the biotinylated C2 gelators in the coassembly due to the specific biotin-avidin interaction. Reverse transcription polymerase chain reaction (RT-PCR) confirms that AV-cells can proliferate without varying gene expression and denaturation. Compared with the interaction between RGD and cells, this avidin-biotin interaction should be much more universal and it is feasible to be employed to promote cell adhesion for most types of cells in 3D matrix.
Baranova, Natalia S; Inforzato, Antonio; Briggs, David C; Tilakaratna, Viranga; Enghild, Jan J; Thakar, Dhruv; Milner, Caroline M; Day, Anthony J; Richter, Ralf P
2014-10-31
Mammalian oocytes are surrounded by a highly hydrated hyaluronan (HA)-rich extracellular matrix with embedded cumulus cells, forming the cumulus cell·oocyte complex (COC) matrix. The correct assembly, stability, and mechanical properties of this matrix, which are crucial for successful ovulation, transport of the COC to the oviduct, and its fertilization, depend on the interaction between HA and specific HA-organizing proteins. Although the proteins inter-α-inhibitor (IαI), pentraxin 3 (PTX3), and TNF-stimulated gene-6 (TSG-6) have been identified as being critical for COC matrix formation, its supramolecular organization and the molecular mechanism of COC matrix stabilization remain unknown. Here we used films of end-grafted HA as a model system to investigate the molecular interactions involved in the formation and stabilization of HA matrices containing TSG-6, IαI, and PTX3. We found that PTX3 binds neither to HA alone nor to HA films containing TSG-6. This long pentraxin also failed to bind to products of the interaction between IαI, TSG-6, and HA, among which are the covalent heavy chain (HC)·HA and HC·TSG-6 complexes, despite the fact that both IαI and TSG-6 are ligands of PTX3. Interestingly, prior encounter with IαI was required for effective incorporation of PTX3 into TSG-6-loaded HA films. Moreover, we demonstrated that this ternary protein mixture made of IαI, PTX3, and TSG-6 is sufficient to promote formation of a stable (i.e. cross-linked) yet highly hydrated HA matrix. We propose that this mechanism is essential for correct assembly of the COC matrix and may also have general implications in other inflammatory processes that are associated with HA cross-linking. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.
Alp, Ebru; Menevse, Sevda; Tulmac, Murat; Yilmaz, Akin; Yalcin, Ridvan; Cengel, Atiye
2011-04-01
The matrix metalloproteinase (MMP) family are key enzymes involved in the breakdown of the extracellular matrix in normal physiological processes, including tissue remodeling, and disease processes, such as arthritis and metastasis. The promoter polymorphism in the MMP2 gene may be responsible for multiple diseases related to extracellular matrix degradation. Therefore, we aimed to investigate the relationship between genotypes or haplotypes of -1575 G/A, -1306 C/T, -790 T/G, and -735 C/T promoter polymorphisms and coronary artery disease (CAD) with or without myocardial infarction (MI) history. This study included 298 patients with angiographically confirmed CAD and 299 age matched controls. Genomic DNA was isolated from whole blood and genotyping was performed by the polymerase chain reaction-restriction fragment length polymorphism method. No significant associations were found between -1575 G/A, -1306 C/T, and -790 T/G polymorphisms and CAD with or without MI history. However, the frequency of the -735 TT genotype was significantly lower in the controls than in the patients with MI alone when compared with the CC genotype (p=0.021). Only the distribution of the ACGC haplotype in CAD patients exhibited a significant difference than that in controls (p<0.05). The distribution of other haplotypes did not differ between CAD patients and controls. The present investigation is the first report to detect an association between MMP2 promoter polymorphisms and CAD with or without MI history in the Turkish population. Further case-control studies in CAD development might be contributed to clarify the role of these polymorphisms.
Satoh, Kazuki; Hata, Mitsumi; Shimizu, Tomoko; Yokota, Hiroshi; Akatsu, Hiroyasu; Yamamoto, Takayuki; Kosaka, Kenji; Yamada, Tatsuo
2005-09-23
In an effort to identify astrocyte-derived molecules that may be intimately associated with progression of Alzheimer's disease (AD), Lib, a type I transmembrane protein belonging to leucine-rich repeat superfamily, has been identified as a distinctly inducible gene, responsive to beta-amyloid as well as pro-inflammatory cytokines in astrocytes. To evaluate the roles of Lib in AD, we investigated Lib expression in AD brain. In non-AD brain, Lib mRNA has been detected in neurons but not in quiescent astrocytes. On the contrary, in AD brain, Lib mRNA is expressed in activated astrocytes associated with senile plaques, but not expressed in neurons around lesions. Lib-expressing glioma cells displayed promotion of migration ability through reconstituted extracellular matrix and recombinant Lib protein bound to constituents of extracellular matrix. These observations suggest that Lib may contribute to regulation of cell-matrix adhesion interactions with respect to astrocyte recruitment around senile plaques in AD brain.
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Jorge S Burns
Full Text Available BACKGROUND: Acquisition of a blood supply is fundamental for extensive tumor growth. We recently described vascular heterogeneity in tumours derived from cell clones of a human mesenchymal stem cell (hMSC strain (hMSC-TERT20 immortalized by retroviral vector mediated human telomerase (hTERT gene expression. Histological analysis showed that cells of the most vascularized tumorigenic clone, -BD11 had a pericyte-like alpha smooth muscle actin (ASMA+ and CD146+ positive phenotype. Upon serum withdrawal in culture, -BD11 cells formed cord-like structures mimicking capillary morphogenesis. In contrast, cells of the poorly tumorigenic clone, -BC8 did not stain for ASMA, tumours were less vascularized and serum withdrawal in culture led to cell death. By exploring the heterogeneity in hMSC-TERT20 clones we aimed to understand molecular mechanisms by which mesenchymal stem cells may promote neovascularization. METHODOLOGY/PRINCIPAL FINDINGS: Quantitative qRT-PCR analysis revealed similar mRNA levels for genes encoding the angiogenic cytokines VEGF and Angiopoietin-1 in both clones. However, clone-BD11 produced a denser extracellular matrix that supported stable ex vivo capillary morphogenesis of human endothelial cells and promoted in vivo neovascularization. Proteomic characterization of the -BD11 decellularized matrix identified 50 extracellular angiogenic proteins, including galectin-1. siRNA knock down of galectin-1 expression abrogated the ex vivo interaction between decellularized -BD11 matrix and endothelial cells. More stable shRNA knock down of galectin-1 expression did not prevent -BD11 tumorigenesis, but greatly reduced endothelial migration into -BD11 cell xenografts. CONCLUSIONS: Decellularized hMSC matrix had significant angiogenic potential with at least 50 angiogenic cell surface and extracellular proteins, implicated in attracting endothelial cells, their adhesion and activation to form tubular structures. hMSC -BD11 surface galectin-1
Enamel Matrix Derivative Promote Primary Human Pulp Cell Differentiation and Mineralization
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Elisabeth Aurstad Riksen
2014-05-01
Full Text Available Enamel matrix derivative (EMD has been found to induce reactive dentin formation; however the molecular mechanisms involved are unclear. The effect of EMD (5–50 μg/mL on primary human pulp cells were compared to untreated cells and cells incubated with 10−8 M dexamethasone (DEX for 1, 2, 3, 7, and 14 days in culture. Expression analysis using Affymetrix microchips demonstrated that 10 μg/mL EMD regulated several hundred genes and stimulated the gene expression of proteins involved in mesenchymal proliferation and differentiation. Both EMD and DEX enhanced the expression of amelogenin (amel, and the dentinogenic markers dentin sialophosphoprotein (DSSP and dentin matrix acidic phosphoprotein 1 (DMP1, as well as the osteogenic markers osteocalcin (OC, BGLAP and collagen type 1 (COL1A1. Whereas, only EMD had effect on alkaline phosphatase (ALP mRNA expression, the stimulatory effect were verified by enhanced secretion of OC and COL1A from EMD treated cells, and increased ALP activity in cell culture medium after EMD treatment. Increased levels of interleukin-6 (IL-6, interleukin-8 (IL-8, and monocyte chemoattractant proteins (MCP-1 in the cell culture medium were also found. Consequently, the suggested effect of EMD is to promote differentiation of pulp cells and increases the potential for pulpal mineralization to favor reactive dentine formation.
Zhang, Zhichun; Tian, Hua; Lv, Ping; Wang, Weiping; Jia, Zhuqing; Wang, Sainan; Zhou, Chunyan; Gao, Xuejun
2015-01-01
Mutation of distal-less homeobox 3 (DLX3) is responsible for human tricho-dento-osseous syndrome (TDO) with amelogenesis imperfecta, indicating a crucial role of DLX3 in amelogenesis. However, the expression pattern of DLX3 and its specific function in amelogenesis remain largely unknown. The aim of this study was to investigate the effects of DLX3 on enamel matrix protein (EMP) genes. By immunohistochemistry assays of mouse tooth germs, stronger immunostaining of DLX3 protein was identified in ameloblasts in the secretory stage than in the pre-secretory and maturation stages, and the same pattern was found for Dlx3 mRNA using Realtime PCR. In a mouse ameloblast cell lineage, forced expression of DLX3 up-regulated the expression of the EMP genes Amelx, Enam, Klk4, and Odam, whereas knockdown of DLX3 down-regulated these four EMP genes. Further, bioinformatics, chromatin immunoprecipitation, and luciferase assays revealed that DLX3 transactivated Enam, Amelx, and Odam through direct binding to their enhancer regions. Particularly, over-expression of mutant-DLX3 (c.571_574delGGGG, responsible for TDO) inhibited the activation function of DLX3 on expression levels and promoter activities of the Enam, Amelx, and Odam genes. Together, our data show that DLX3 promotes the expression of the EMP genes Amelx, Enam, Klk4, and Odam in amelogenesis, while mutant-DLX3 disrupts this regulatory function, thus providing insights into the molecular mechanisms underlying the enamel defects of TDO disease.
Sueblinvong, Viranuj; Neveu, Wendy A; Neujahr, David C; Mills, Stephen T; Rojas, Mauricio; Roman, Jesse; Guidot, David M
2014-01-01
Fibrotic lung diseases increase with age. Previously we determined that senescence increases tissue expression of fibronectin EDA (Fn-EDA) and decreases fibroblast expression of Thy-1, and that fibrocytes contribute to fibrosis following bleomycin-induced lung injury in mice. In this study we hypothesized that fibroblasts lacking Thy-1 expression produce an extracellular matrix that promotes fibrocyte retention and myofibroblast transdifferentiation, thereby promoting fibrogenesis. Young and old mice were treated with bleomycin intratracheally; fibrocytes in the bone marrow, blood, and lungs were quantified, and lung fibroblast Thy-1 expression assessed. Bone marrow-derived fibrocytes were cultured on matrices derived from Thy-1(+) or Thy-1(-) fibroblasts ± the pro-fibrotic cytokine TGFβ1. Older mice had more fibrocytes in their bone marrows at baseline and more fibrocytes in their lungs following bleomycin treatment. In parallel, lung fibroblasts in older mice had lower expression of Thy-1 at baseline that increased transiently 7 days after bleomycin treatment but then rapidly waned such that 14 days after bleomycin treatment Thy-1 expression was again markedly lower. Fibrocytes cultured on matrices derived from Thy-1(-) fibroblasts + TGFβ1 had increased gene expression for collagen type 1, fibronectin, Fn-EDA, and α-smooth muscle actin. In parallel, whereas the matrices derived from Thy-1(-) fibroblasts stimulated phosphorylation of Akt in cultured fibrocytes, the matrices derived from Thy-1(+) fibroblasts induced apoptosis. These findings suggest that senescence increases fibrocyte recruitment to the lung following injury and that loss of Thy-1 expression by lung fibroblasts promotes fibrocyte retention and myofibroblast trans-differentiation that renders the "aging lung" susceptible to fibrosis.
Promoter polymorphism in the matrix metalloproteinase-1 and risk of cervical cancer in Korean women.
Ju, Woong; Kang, Sokbom; Kim, Jae Weon; Park, Noh Hyun; Song, Yong Sang; Kang, Soon Beom; Lee, Hyo Pyo
2005-01-20
The aim of this investigation was to analyze the association between a single nucleotide polymorphism (SNP) in the matrix metalloproteinase (MMP)-1 promoter gene -1607 bp region and cervical cancer risk in Korean women. The blood samples of 232 cervical cancer patients and 332 non-cancer control subjects who managed at Seoul National University Hospital from 1999 to 2002 were collected. Polymorphism in MMP-1 promoter -1607 region was determined using TaqMan method. Allele frequency and genotype distribution in the cervical cancer group were compared with those of the control group to determine whether this polymorphism elevates the susceptibility of Korean women to cervical cancer. The relationship between this SNP and cancer invasiveness was also evaluated by collating clinicopathologic data of those in the cancer group, such as FIGO stage, lymph node status, histologic type and parametrial invasion. In the cervical cancer group, the allele frequency of 2G was 66.1%, in the control group 68.2%, showing no significant difference (P=0.41). Similarly the genotypes with insertion (2G/2G) or deletion (1G/1G) polymorphism showed no increased risk for cervical cancer susceptibility compared with 1G/2G genotype. A subgroup analysis of the clinicopathologic parameters in cancer group also showed no significant difference suggesting the lack of an association between SNP of the MMP-1 promoter -1607 bp region and cervical cancer invasiveness. In conclusion, this study shows that Korean with specific polymorphism in MMP-1 are neither more susceptible to develop cervical cancer nor more vulnerable for cancer progression.
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Jittranan Kaewprag
Full Text Available Production of matrix metalloproteinases (MMPs for degradation of extracellular matrix is a vital step in cancer metastasis. We investigated the effects of HPV16 oncoproteins (16E6, 16E6*I and 16E7, either individually or combined, on the transcription of 7 MMPs implicated in cervical cancer invasiveness. The levels of 7 MMPs reported to be increased in cervical cancer were determined in C33A stably expressing different HPV16 oncoproteins using quantitative RT-PCR and compared with invasion ability of cell lines using in vitro invasion and wound healing assays. Overexpression of MMP-2 and MT1-MMP was detected in HPV16E6E7 expressing cells which correlated with increased cell invasion. Combination of HPV oncoproteins always showed greater effects than its individual form. Inhibition of cell invasion using a specific MMP-2 inhibitor, OA-Hy, and anti-MT1-MMP antibody confirmed that invasion in these cells was dependent on both MMP-2 and MT1-MMP expression. Depletion of HPV16E6E7 by shRNA-mediated knock-down experiments resulted in decreased MMP-2 and MT1-MMP expression levels as well as reduced invasion ability which strongly suggested specific effects of HPV oncoproteins on both MMPs and on cell invasion. Immunohistochemistry study in invasive cervical cancers confirmed the enhanced in vivo expression of these two MMPs in HPV16-infected cells. In addition, possible sites required by HPV16E6E7 on the MMP-2 and MT1-MMP promoters were investigated and PEA3 (at -552/-540 for MMP-2, -303 for MT1-MMP and Sp1 (at -91 for MMP-2, -102 for MT1-MMP binding sites were shown to be essential for mediating their transactivation activity. In conclusion, our study demonstrated that HPV16E6 and E7 oncoproteins cooperate in promoting cervical cancer invasiveness by specifically upregulating MMP-2 and MT1-MMP transcription in a similar manner.
Kaewprag, Jittranan; Umnajvijit, Wareerat; Ngamkham, Jarunya; Ponglikitmongkol, Mathurose
2013-01-01
Production of matrix metalloproteinases (MMPs) for degradation of extracellular matrix is a vital step in cancer metastasis. We investigated the effects of HPV16 oncoproteins (16E6, 16E6*I and 16E7), either individually or combined, on the transcription of 7 MMPs implicated in cervical cancer invasiveness. The levels of 7 MMPs reported to be increased in cervical cancer were determined in C33A stably expressing different HPV16 oncoproteins using quantitative RT-PCR and compared with invasion ability of cell lines using in vitro invasion and wound healing assays. Overexpression of MMP-2 and MT1-MMP was detected in HPV16E6E7 expressing cells which correlated with increased cell invasion. Combination of HPV oncoproteins always showed greater effects than its individual form. Inhibition of cell invasion using a specific MMP-2 inhibitor, OA-Hy, and anti-MT1-MMP antibody confirmed that invasion in these cells was dependent on both MMP-2 and MT1-MMP expression. Depletion of HPV16E6E7 by shRNA-mediated knock-down experiments resulted in decreased MMP-2 and MT1-MMP expression levels as well as reduced invasion ability which strongly suggested specific effects of HPV oncoproteins on both MMPs and on cell invasion. Immunohistochemistry study in invasive cervical cancers confirmed the enhanced in vivo expression of these two MMPs in HPV16-infected cells. In addition, possible sites required by HPV16E6E7 on the MMP-2 and MT1-MMP promoters were investigated and PEA3 (at -552/-540 for MMP-2, -303 for MT1-MMP) and Sp1 (at -91 for MMP-2, -102 for MT1-MMP) binding sites were shown to be essential for mediating their transactivation activity. In conclusion, our study demonstrated that HPV16E6 and E7 oncoproteins cooperate in promoting cervical cancer invasiveness by specifically upregulating MMP-2 and MT1-MMP transcription in a similar manner.
Directory of Open Access Journals (Sweden)
Zhichun Zhang
Full Text Available Mutation of distal-less homeobox 3 (DLX3 is responsible for human tricho-dento-osseous syndrome (TDO with amelogenesis imperfecta, indicating a crucial role of DLX3 in amelogenesis. However, the expression pattern of DLX3 and its specific function in amelogenesis remain largely unknown. The aim of this study was to investigate the effects of DLX3 on enamel matrix protein (EMP genes. By immunohistochemistry assays of mouse tooth germs, stronger immunostaining of DLX3 protein was identified in ameloblasts in the secretory stage than in the pre-secretory and maturation stages, and the same pattern was found for Dlx3 mRNA using Realtime PCR. In a mouse ameloblast cell lineage, forced expression of DLX3 up-regulated the expression of the EMP genes Amelx, Enam, Klk4, and Odam, whereas knockdown of DLX3 down-regulated these four EMP genes. Further, bioinformatics, chromatin immunoprecipitation, and luciferase assays revealed that DLX3 transactivated Enam, Amelx, and Odam through direct binding to their enhancer regions. Particularly, over-expression of mutant-DLX3 (c.571_574delGGGG, responsible for TDO inhibited the activation function of DLX3 on expression levels and promoter activities of the Enam, Amelx, and Odam genes. Together, our data show that DLX3 promotes the expression of the EMP genes Amelx, Enam, Klk4, and Odam in amelogenesis, while mutant-DLX3 disrupts this regulatory function, thus providing insights into the molecular mechanisms underlying the enamel defects of TDO disease.
MicroRNA 21 promotes glioma invasion by targeting matrix metalloproteinase regulators.
Gabriely, Galina; Wurdinger, Thomas; Kesari, Santosh; Esau, Christine C; Burchard, Julja; Linsley, Peter S; Krichevsky, Anna M
2008-09-01
Substantial data indicate that microRNA 21 (miR-21) is significantly elevated in glioblastoma (GBM) and in many other tumors of various origins. This microRNA has been implicated in various aspects of carcinogenesis, including cellular proliferation, apoptosis, and migration. We demonstrate that miR-21 regulates multiple genes associated with glioma cell apoptosis, migration, and invasiveness, including the RECK and TIMP3 genes, which are suppressors of malignancy and inhibitors of matrix metalloproteinases (MMPs). Specific inhibition of miR-21 with antisense oligonucleotides leads to elevated levels of RECK and TIMP3 and therefore reduces MMP activities in vitro and in a human model of gliomas in nude mice. Moreover, downregulation of miR-21 in glioma cells leads to decreases of their migratory and invasion abilities. Our data suggest that miR-21 contributes to glioma malignancy by downregulation of MMP inhibitors, which leads to activation of MMPs, thus promoting invasiveness of cancer cells. Our results also indicate that inhibition of a single oncomir, like miR-21, with specific antisense molecules can provide a novel therapeutic approach for "physiological" modulation of multiple proteins whose expression is deregulated in cancer.
Hasaneen, Nadia A; Cao, Jian; Pulkoski-Gross, Ashleigh; Zucker, Stanley; Foda, Hussein D
2016-02-17
Idiopathic pulmonary fibrosis (IPF) is a chronic progressively fatal disease. Extracellular Matrix Metalloproteinase Inducer (EMMPRIN) is a glycosylated transmembrane protein that induces the expression of some matrix metalloproteinase (MMP) in neighboring stromal cells through direct epithelial-stromal interactions. EMMPRIN is highly expressed in type II alveolar epithelial cells at the edges of the fibrotic areas in IPF lung sections. However, the exact role of EMMPRIN in IPF is unknown. To determine if EMMPRIN contributes to lung fibroblast proliferation, resistance to apoptosis, and differentiation to myofibroblasts, normal Human lung fibroblasts (NHLF) transiently transfected with either EMMPRIN/GFP or GFP were treated with TGF- β1 from 0 to 10 ng/ml for 48 h and examined for cell proliferation (thymidine incorporation), apoptosis (FACS analysis and Cell Death Detection ELISA assay), cell migration (Modified Boyden chamber) and differentiation to myofibroblasts using Western blot for α-smooth actin of cell lysates. The effect of EMMPRIN inhibition on NHLF proliferation, apoptosis, migration and differentiation to myofibroblasts after TGF- β1 treatment was examined using EMMPRIN blocking antibody. We examined the mechanism by which EMMPRIN induces its effects on fibroblasts by studying the β-catenin/canonical Wnt signaling pathway using Wnt luciferase reporter assays and Western blot for total and phosphorylated β-catenin. Human lung fibroblasts overexpressing EMMPRIN had a significant increase in cell proliferation and migration compared to control fibroblasts. Furthermore, EMMPRIN promoted lung fibroblasts resistance to apoptosis. Lung fibroblasts overexpressing EMMPRIN showed a significantly increased expression of α- smooth muscle actin, a marker of differentiation to myofibroblasts compared to control cells. TGF-β1 increased the expression of EMMPRIN in lung fibroblasts in a dose-dependent manner. Attenuation of EMMPRIN expression with the use of an
Liu, Ming-Han; Sun, Chao; Yao, Yuan; Fan, Xin; Liu, Huan; Cui, You-Hong; Bian, Xiu-Wu; Huang, Bo; Zhou, Yue
2016-05-04
The mechanical environment is crucial for intervertebral disc degeneration (IDD). However, the mechanisms underlying the regulation of cartilage endplate (CEP) calcification by altered matrix stiffness remain unclear. In this study, we found that matrix stiffness of CEP was positively correlated with the degree of IDD, and stiff matrix, which mimicked the severe degeneration of CEP, promoted inorganic phosphate-induced calcification in CEP chondrocytes. Co-expression analysis of the miRNA and mRNA profiles showed that increasing stiffness resulted in up-regulation of miR-20a and down-regulation of decreased ankylosis protein homolog (ANKH) during inorganic phosphate-induced calcification in CEP chondrocytes. Through a dual luciferase reporter assay, we confirmed that miR-20a directly targets 3'-untranslated regions of ANKH. The inhibition of miR-20a attenuated the calcium deposition and calcification-related gene expression, whereas the overexpression of miR-20a enhanced calcification in CEP chondrocytes on stiff matrix. The rescue of ANKH expression restored the decreased pyrophosphate efflux and inhibited calcification. In clinical samples, the levels of ANKH expression were inversely associated with the degeneration degree of CEP. Thus, our findings demonstrate that the miR-20a/ANKH axis mediates the stiff matrix- promoted CEP calcification, suggesting that miR-20a and ANKH are potential targets in restraining the progression of IDD.
Galie, Peter A.; Westfall, Margaret V.; Stegemann, Jan P.
2011-01-01
Introduction The fibroblast-myofibroblast transition is an important event in the development of cardiac fibrosis and scar formation initiated after myocardial ischemia. The goals of the present study were to better understand the contribution of environmental factors to this transition and determine whether myofibroblasts provide equally important feedback to the surrounding environment. Methods The influence of matrix stiffness and serum concentration on the myofibroblast transition was assessed by measuring message levels of a panel of cardiac fibroblast phenotype markers using quantitative rtPCR. Cell-mediated gel compaction measured the influence of environmental factors on cardiac fibroblast contractility. Immunohistochemistry characterized α-SMA expression and cell morphology, while static and dynamic compression testing evaluated the effect of the cell response on the mechanical properties of the cell-seeded collagen hydrogels. Results Both reduced serum content and increased matrix stiffness contributed to the myofibroblast transition, as indicated by contractile compaction of the gels, increased message levels of col3α1 and α-SMA, and a less stellate morphology. However, the effects of serum and matrix stiffness were not additive. Mechanical testing indicated the cell-seeded gels became less viscoelastic with time, and that reduced serum content also increased the initial elastic properties of the gel. Conclusions The results suggest that reduced serum and increased matrix stiffness promote the myofibroblast phenotype in the myocardium. This transition both enhances and is promoted by matrix stiffness, indicating the presence of positive feedback that may contribute to the pathogenesis of cardiac fibrosis. Summary Lower serum content and increased matrix stiffness accelerated the transition of cardiac fibroblasts seeded in collagen hydrogels to a myofibroblast phenotype, though their effects were not additive. Reduced serum also affected mechanical
Influence of double promotion on HDS catalysts prepared by urea-matrix combustion synthesis
Energy Technology Data Exchange (ETDEWEB)
Gonzalez-Cortes, Sergio L. [Laboratorio de Cinetica y Catalisis, Departamento de Quimica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Xiao, Tian-Cun; Lin, Tsung-Wu; Green, Malcolm L.H. [Wolfson Catalysis Centre, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR (United Kingdom)
2006-04-11
The stringent environmental regulations in the US, Japan and Europe are requiring significant improvement in the quality of transportation fuels. A new strategy based on urea-matrix combustion method for the synthesis of alumina-supported molybdate-based mixed oxides (i.e., bimetallic and trimetallic oxides) has been applied. This permits to control the alumina-mixed oxide interaction and therefore the HDS catalytic behaviour. The oxidic and sulfurized states of the HDS catalysts were characterized by X-ray diffraction (XRD), laser Raman spectroscopy (LRS), temperature-programmed reduction (TPR) and high resolution transmission electron microscopy (HRTEM). Catalyst performance was evaluated using a tubular fixed-bed reactor and the hydrodesulfurization of thiophene under normal pressure as model reaction. It has been found that Ni-promoted alumina-supported MoO{sub 3} catalyst precursor presented a non well-ordered structure of Ni-Mo phase supported on alumina surface. However, when cobalt was added to Ni-Mo precursor the {beta}-isomorph stability was significantly improved and the formation of alumina-supported {beta}-Co{sub 0.5}Ni{sub 0.5}MoO{sub 4} was observed. The activation treatments markedly affect the catalyst structure and hence the HDS catalytic performance. The catalyst series pretreated in H{sub 2}S-H{sub 2} was 2-3 times more active than those C{sub 4}H{sub 4}S-H{sub 2}-pretreated catalysts and ca. 2-10 times more active than the pre-reduced samples. A significantly greater HDS activity of H{sub 2}S-H{sub 2}-pretreated Co{sub 0.5}Mg{sub 0.5}MoS{sub x}/{gamma}-Al{sub 2}O{sub 3} catalyst was observed, which is attributed to the fact that both promoters are into the same network interacting directly with the molybdenum. This feature hinders not only the segregation of cobalt sulfide, but also the formation of long MoS{sub 2} slabs. (author)
Prideaux, Matthew; Loveridge, Nigel; Pitsillides, Andrew A; Farquharson, Colin
2012-01-01
Osteocytes are terminally differentiated osteoblasts which reside in a mineralized extracellular matrix (ECM). The factors that regulate this differentiation process are unknown. We have investigated whether ECM mineralization could promote osteocyte formation. To do this we have utilised MLO-A5 pre-osteocyte-like cells and western blotting and comparative RT-PCR to examine whether the expression of osteocyte-selective markers is elevated concurrently with the onset of ECM mineralization. Secondly, if mineralization of the ECM is indeed a driver of osteocyte formation, we reasoned that impairment of ECM mineralization would result in a reversible inhibition of osteocyte formation. Supplementation of MLO-A5 cell cultures with ascorbic acid and phosphate promoted progressive ECM mineralization as well as temporally associated increases in expression of the osteocyte-selective markers, E11/gp38 glycoprotein and sclerostin. Consistent with a primary role for ECM mineralization in osteocyte formation, we also found that inhibition of ECM mineralization, by omitting phosphate or adding sodium pyrophosphate, a recognized inhibitor of hydroxyapatite formation, resulted in a 15-fold decrease in mineral deposition that was closely accompanied by lower expression of E11 and other osteocyte markers such as Dmp1, Cd44 and Sost whilst expression of osteoblast markers Ocn and Col1a increased. To rule out the possibility that such restriction of ECM mineralization may produce an irreversible modification in osteoblast behaviour to limit E11 expression and osteocytogenesis, we also measured the capacity of MLO-A5 cells to re-enter the osteocyte differentiation programme. We found that the mineralisation process was re-initiated and closely allied to increased expression of E11 protein after re-administration of phosphate or omission of sodium pyrophosphate, indicating an ECM mineralization-induced restoration in osteocyte formation. These results emphasise the importance of cell
CD14{sup +} monocytes promote the immunosuppressive effect of human umbilical cord matrix stem cells
Energy Technology Data Exchange (ETDEWEB)
Wang, Ding, E-mail: qqhewd@gmail.com [The State Key Laboratory of Experimental Hematology, Institute of Hematology and Hospital of Blood Diseases, Chinese Academy of Medical Sciences and Peking Union of Medical College, 288 Nanjing Road, Tianjin 300020 (China); TEDA Life and Technology Research Center, Institute of Hematology, Chinese Academy of Medical Sciences, TEDA, Tianjin (China); Chen, Ke, E-mail: chenke_59@hotmail.com [The State Key Laboratory of Experimental Hematology, Institute of Hematology and Hospital of Blood Diseases, Chinese Academy of Medical Sciences and Peking Union of Medical College, 288 Nanjing Road, Tianjin 300020 (China); TEDA Life and Technology Research Center, Institute of Hematology, Chinese Academy of Medical Sciences, TEDA, Tianjin (China); Du, Wei Ting, E-mail: duwtpumc@yahoo.com.cn [The State Key Laboratory of Experimental Hematology, Institute of Hematology and Hospital of Blood Diseases, Chinese Academy of Medical Sciences and Peking Union of Medical College, 288 Nanjing Road, Tianjin 300020 (China); Han, Zhi-Bo, E-mail: zhibohan@hotmail.com [The State Key Laboratory of Experimental Hematology, Institute of Hematology and Hospital of Blood Diseases, Chinese Academy of Medical Sciences and Peking Union of Medical College, 288 Nanjing Road, Tianjin 300020 (China); TEDA Life and Technology Research Center, Institute of Hematology, Chinese Academy of Medical Sciences, TEDA, Tianjin (China); Ren, He, E-mail: knifesharp2000@hotmail.com [National Engineering Research Center of Cell Products, AmCellGene Co. Ltd, TEDA, Tianjin (China); Chi, Ying, E-mail: caizhuying@hotmail.com [The State Key Laboratory of Experimental Hematology, Institute of Hematology and Hospital of Blood Diseases, Chinese Academy of Medical Sciences and Peking Union of Medical College, 288 Nanjing Road, Tianjin 300020 (China); TEDA Life and Technology Research Center, Institute of Hematology, Chinese Academy of Medical Sciences, TEDA, Tianjin (China); and others
2010-09-10
Here, the effect of CD14{sup +} monocytes on human umbilical cord matrix stem cell (hUC-MSC)-mediated immunosuppression was studied in vitro. hUC-MSCs exerted a potent inhibitory effect on the proliferation and interferon-{gamma} (IFN-{gamma}) secretion capacities of CD4{sup +} and CD8{sup +} T cells in response to anti-CD3/CD28 stimulation. Transwell co-culture system revealed that the suppressive effect was primarily mediated by soluble factors. Addition of prostaglandin synthesis inhibitors (indomethacin or NS-398) almost completely abrogated the immunosuppression activity of hUC-MSCs, identifying prostaglandin E{sub 2} (PGE{sub 2}) as an important soluble mediator. CD14{sup +} monocytes were found to be able to enhance significantly the immunosuppressive effect of hUC-MSCs in a dose-dependent fashion. Moreover, the inflammatory cytokine IL-1{beta}, either exogenously added or produced by CD14{sup +} monocytes in culture, could trigger expression of high levels of PGE{sub 2} by hUC-MSCs, whereas inclusion of the IL-1 receptor antagonist (IL-1RA) in the culture down-regulated not only PGE{sub 2} expression, but also reversed the promotional effect of CD14{sup +} monocytes and partially restored CD4{sup +} and CD8{sup +} T cell proliferation and IFN-{gamma} secretion. Our data demonstrate an important role of monocytes in the hUC-MSC-induced immunomodulation, which may have important implications in future efforts to explore the clinical potentials of hUC-MSCs.
Blanco-Mezquita, Tomas; Martinez-Garcia, Carmen; Proença, Rui; Zieske, James D.; Bonini, Stefano; Lambiase, Alessandro; Merayo-Lloves, Jesus
2013-01-01
Purpose. Nerve growth factor (NGF) is a neuropeptide essential for the development, survival, growth, and differentiation of corneal cells. Its effects are mediated by both TrkA and p75 receptors. Clinically relevant use of NGF was introduced to treat neurotrophic ulcerations in patients. Herein, we examine the mechanisms by which NGF enhances epithelial wound healing both in vivo and in vitro. Methods. An animal model using adult hens was implemented for the in vivo experiments. Laser ablation keratectomy was performed and animals were observed for up to 7 days. Epithelial healing was measured with fluorescein. In addition, proliferation was measured using BrdU incorporation and both TrkA and matrix metalloprotease-9 (MMP-9) expression were measured by immunohistochemistry (IHC) and Western blot (WB). In vitro experiments were carried out with telomerase-immortalized human corneal epithelial cells (HCLE). The rate of proliferation was measured using a colorimetric assay and BrdU incorporation. Real-time migration was evaluated with an inverted microscope. MMP-9 expression was evaluated by immunocytochemistry (ICC), WB, zymography, and RT-PCR. Finally, beta-4 integrin (β4) expression was assessed by ICC and WB. Results. Faster epithelial healing was observed in NGF-treated corneas compared with controls (P < 0.01). These corneas showed increased proliferation, TrkA upregulation, and enhanced MMP-9 presence (P < 0.01). In vitro, faster spreading and migration were observed in response to NGF (P < 0.01). Enhanced proliferation, as well as enhanced TrkA and MMP-9 expression, and decreased β4 levels were observed after adding NGF (P < 0.01). Conclusions. NGF plays a major role during the epithelial healing process by promoting migration, a process that is accelerated by cell spreading. This effect is mediated by both the upregulation of MMP-9 and cleavage of β4 integrin. PMID:23640040
Broggini, Thomas; Schnell, Lisa; Ghoochani, Ali; Mateos, José María; Buchfelder, Michael; Wiendieck, Kurt; Schäfer, Michael K.; Eyupoglu, Ilker Y.; Savaskan, Nicolai E.
2016-01-01
The Plasticity Related Gene family covers five, brain-specific, transmembrane proteins (PRG1-5, also termed LPPR1-5) that operate in neuronal plasticity during development, aging and brain trauma. Here we investigated the role of the PRG family on axonal and filopodia outgrowth. Comparative analysis revealed the strongest outgrowth induced by PRG3 (LPPR1). During development, PRG3 is ubiquitously located at the tip of neuronal processes and at the plasma membrane and declines with age. In utero electroporation of PRG3 induced dendritic protrusions and accelerated spine formations in cortical pyramidal neurons. The neurite growth promoting activity of PRG3 requires RasGRF1 (RasGEF1/Cdc25) mediated downstream signaling. Moreover, in axon collapse assays, PRG3-induced neurites resisted growth inhibitors such as myelin, Nogo-A (Reticulon/RTN-4), thrombin and LPA and impeded the RhoA-Rock-PIP5K induced neurite repulsion. Transgenic adult mice with constitutive PRG3 expression displayed strong axonal sprouting distal to a spinal cord lesion. Moreover, fostered PRG3 expression promoted complex motor-behavioral recovery compared to wild type controls as revealed in the Schnell swim test (SST). Thus, PRG3 emerges as a developmental RasGRF1-dependent conductor of filopodia formation and axonal growth enhancer. PRG3-induced neurites resist brain injury-associated outgrowth inhibitors and contribute to functional recovery after spinal cord lesions. Here, we provide evidence that PRG3 operates as an essential neuronal growth promoter in the nervous system. Maintaining PRG3 expression in aging brain may turn back the developmental clock for neuronal regeneration and plasticity. PMID:27744421
Lakshmanan, Rajesh; Kumaraswamy, Priyadharshini; Krishnan, Uma Maheswari; Sethuraman, Swaminathan
2016-08-01
The major loss of tissue extracellular matrix (ECM) after myocardial ischemia is a serious burden that gradually leads to heart failure. Due to lack of available treatment methods to restore the cardiac function, various research strategies have come up to treat the ischemic myocardium. However these have met with limited success due to the complexity of the cardiac tissue, which exhibits a nanofibrous collagenous matrix with spatio-temporal localization of a combination of growth factors. To mimic the topographical and chemical cues of the natural cardiac tissue, we have fabricated a growth factor embedded nanofibrous scaffold through electrospinning. In our previous work, we have reported a nanofibrous matrix made of PLCL and PEOz with an average diameter of 500 nm. The scaffold properties were specifically characterized in vitro for cardio-compatibility. In the present study, we have loaded dual growth factors VEGF and bFGF in the nanofiber matrix and investigated its suitability for cardiac tissue engineering. The encapsulation and release of dual growth factors from the matrix were studied using XPS and ELISA. Bioactivity of the loaded growth factors towards proliferation and migration of endothelial cells (HUVECs) was evaluated through MTS and Boyden chamber assays respectively. The efficiency of growth factors on the nanofibrous matrix to activate signaling molecules was studied in HUVECs through gene expression analysis. Preclinical evaluation of the growth factor embedded nanofibrous patch in a rabbit acute myocardial infarction (AMI) model was studied and cardiac function assessment was made through ECG and echocardiography. The evidence for angiogenesis in the patch secured regions was analyzed through histopathology and immunohistochemistry. Our results confirm the effectiveness of growth factor embedded nanofiber matrix in restoration of cardiac function after ischemia when compared to conventional patch material thereby exhibiting promise as a
Jalili, Reza B; Moeen Rezakhanlou, Alireza; Hosseini-Tabatabaei, Azadeh; Ao, Ziliang; Warnock, Garth L; Ghahary, Aziz
2011-07-01
Islet transplantation represents a viable treatment for type 1 diabetes. However, due to loss of substantial mass of islets early after transplantation, islets from two or more donors are required to achieve insulin independence. Islet-extracellular matrix disengagement, which occurs during islet isolation process, leads to subsequent islet cell apoptosis and is an important contributing factor to early islet loss. In this study, we developed a fibroblast populated collagen matrix (FPCM) as a novel scaffold to improve islet cell viability and function post-transplantation. FPCM was developed by embedding fibroblasts within type-I collagen and used as scaffold for islet grafts. Viability and insulin secretory function of islets embedded within FPCM was evaluated in vitro and in a syngeneic murine islet transplantation model. Islets embedded within acellular matrix or naked islets were used as control. Islet cell survival and function was markedly improved particularly after embedding within FPCM. The composite scaffold significantly promoted islet isograft survival and reduced the critical islet mass required for diabetes reversal by half (from 200 to 100 islets per recipient). Fibroblast embedded within FPCM produced fibronectin and growth factors and induced islet cell proliferation. No evidence of fibroblast over-growth within composite grafts was noticed. These results confirm that FPCM significantly promotes islet viability and functionality, enhances engraftment of islet grafts and decreases the critical islet mass needed to reverse hyperglycemia. This promising finding offers a new approach to reducing the number of islet donors per recipient and improving islet transplant outcome.
Institute of Scientific and Technical Information of China (English)
Hong-Xia Bi; Han-Bing Shi; Ting Zhang; Ge Cui
2015-01-01
Background:As a novel molecular markerof non-small cell lung cancer (NSCLC),PRDI-BF1 and RIZ homology domain containing protein 14 (PRDM 14) is over-expressed in NSCLC tumor tissues.Extracellular matrix degradation mediated by the balance between matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) is one of the most important mechanism in lung cancer metastasis.This study aimed to determine if PRDM 14 promoted the migration of NSCLC cells through extracellular matrix degradation mediated by change of MMP/TIMP expression.Methods:The expression of PRDM14 was down-regulated in human cell line A 549 after transfection with lentiviral vector-mediated short-hairpin ribonucleic acids (shRNAs) which targeted the PRDM 14 promoter.Cellular migration ofshRNA-infected cells was detected by a scratch wound healing assay and transwell cell migration assay.Expression levels of MMP1,MMP2,TIMP1,and TIMP2 were measured by quantitative real-time polymerase chain reaction (RT-PCR).Results:Migration ofPRDM 14-shRNA-infected cells was significantly inhibited relative to control cells as measured by the scratch wound healing (P ＜ 0.05) and transwell cell migration assays (P ＜ 0.01).The expression of MMP1 in A549 cells infected by PRDM14-shRNA was down-regulated significantly (P ＜ 0.01),whereas the expression of TIMPl and TIMP2 was up-regulated significantly (P ＜ 0.01).Conclusions:PRDM 14 accelerates A549 cells migration in vitro through extracellular matrix degradation.PRDM 14 is considered as a potential therapeutic target in metastatic NSCLC.
Coon, Charles I; Fiering, Steven; Gaudet, Justin; Wyatt, Colby A; Brinckerhoff, Constance E
2009-09-01
Matrix metalloproteinases (MMPs) comprise a family of more than 20 members, each with the ability to degrade components of the extracellular matrix. The interstitial collagenases have the unique capacity to degrade the stromal collagens, types I, II and III, the body's most abundant proteins. These collagenases include MMP-1, MMP-8, MMP-13 and MMP-14. MMP-1, with a very broad expression pattern, has major roles in mediating matrix destruction in many diseases. We have described a single nucleotide polymorphism (SNP) in the MMP-1 promoter that augments transcription. This SNP is the presence or absence of an extra guanine (G) at -1607 bp, which creates the sequence 5'-GGAA-3'(2G allele), and which is an ETS binding site. Compared to the 1G allele (5'-GAA-3'), the 2G SNP is associated with enhanced transcription of MMP-1 and increased enzymatic activity. Although murine systems are often used to model human diseases, mice have only distant homologues of human MMP-1. Therefore, we used a technique for the targeted insertion of a single copy of a gene at the HPRT locus to compare expression of the 1G and 2G alleles. We generated transgenic mice with -4372 bp of the human MMP-1 promoter containing either the 1G or 2G SNP in front of the lac Z (E.coli ss-galactosidase) gene. We measured the relative expression of the transgenes in vitro in embryonic stem (ES) cells and in fibroblasts derived from embryonic mice. Our data show modest constitutive expression of ss-galactosidase mRNA and protein from these alleles, with the 2G allele more transcriptionally active than the 1G allele. We conclude that these mice represent a model for integration of a single copy of the human MMP-1 promoter into the murine genome, and could be used to study MMP-1 gene expression in a murine system.
Liu, Y; Ning, W H; Shen, X H; Guo, D L; Guo, L
2016-11-24
Objective: To observe the effects of tumor necrosis factor-α (TNF-α) and platelet derived growth factor (PDGF) on vascular neointimal hyperplasia on matrix metalloproteinase 9/2 gene knockout (MMP9/2(-/-)) mice and explore related mechanisms. Methods: Mice of control group, MMP9(-/-) group, MMP2(-/-) group and MMP9/2(-/-) group were studied. Femoral artery was injured by transluminal wire, the mRNA expression levels of TNF-α and PDGF on femoral artery were detected by RT-PCR; the protein expression of MMP9 and MMP2 were assessed by Western blot on day 0, 1, 3, 7, 14 and 28 post injury. Mice in control group received TNF-α(5 ng/ml, 0.10 ml), TNF-α(0.05 ml)+ MMP inhibitor SB-3CT(0.50 ng/ml, 0.05 ml) injection, or PDGF-bb (10 ng/ml, 0.10 ml)and PDGF-bb(0.05 ml)+ SB-3CT(0.05 ml)injection around injured artery, intimal hyperplasia at 2 and 4 weeks after injury was observed. Intimal hyperplasia at 2 and 4 weeks after injury was also observed in MMP9/2(-/-) mice. TNF-α(5 ng/ml, 0.10 ml)was injected to MMP2(-/-) mice, PDGF-bb (0.1 ml) was injected to MMP9(-/-) mice around injured artery, intimal hyperplasia at 2 and 4 weeks after injury was observed. The degree of neointimal hyperplasia were observed by the Elastica-van Gieson staining and the area of neointima and media of the arteries were measured by SigmaPlot and intima ratio was calculated. Vascular smooth muscle cell (VSMC) mediums of MMP9(-/-) and MMP2(-/-) mice were stimulated by TNF-α and PDGF-bb, respectively, and migration assay, and proliferation assay were performed, relative migration and proliferation cells numbers were counted. Results: (1) mRNA expression of TNF-α (235.33±23.68) and PDGF-bb (3.30±0.56) in femoral arteries peaked at 1 day after injury, while MMP9 or MMP2 protein expression peaked at 7 or 28 days after injury. (2)In control mice, TNF-α intervention significantly enhanced intimal hyperplasia at 2 weeks after injury (2.21±0.05 vs. 1.55±0.03 in blank control group, Phyperplasia at
The promoter polymorphism -1562C/T in matrix metalloproteinase-9 and COPD severity
Directory of Open Access Journals (Sweden)
D. G. Yanbaeva
2006-12-01
Full Text Available Chronic obstructive pulmonary disease (COPD is a complex heterogeneous respiratory disease. COPD is characterized by a progressive irreversible airflow limitation that is due to a loss of lung elasticity resulting from peripheral airflow obstruction (chronic bronchitis and parenchymal destruction (emphysema. Matrix metalloproteinases (MMP are a major group of proteases known to regulate extracellular matrix turnover. They have been suggested to be important in the process of lung diseases associated with tissue remodeling. Polymorphisms in MMPs which known to upregulate their activity may result in the degradation of a lung matrix. A case-control study was performed to investigate the association of polymorphisms of MMP type 1 (-1607G/GG, 9 (-1562C/T and 12 (-82A/G genes with COPD and disease severity. A total of 309 COPD patients admitted to departments of respiratory medicine have been recruited in Ufa city hospitals (## 13, 21, and 22. COPD patients have been undergone a spirometry and a physical examination by a chest physician to refer the GOLD II-IV stages. The control group comprised of 305 healthy subjects without evidence of chronic diseases (Table Basic characteristic of study groups.
Directory of Open Access Journals (Sweden)
JA DeQuach
2012-06-01
Full Text Available Peripheral artery disease (PAD currently affects approximately 27 million patients in Europe and North America, and if untreated, may progress to the stage of critical limb ischemia (CLI, which has implications for amputation and potential mortality. Unfortunately, few therapies exist for treating the ischemic skeletal muscle in these conditions. Biomaterials have been used to increase cell transplant survival as well as deliver growth factors to treat limb ischemia; however, existing materials do not mimic the native skeletal muscle microenvironment they are intended to treat. Furthermore, no therapies involving biomaterials alone have been examined. The goal of this study was to develop a clinically relevant injectable hydrogel derived from decellularized skeletal muscle extracellular matrix and examine its potential for treating PAD as a stand-alone therapy by studying the material in a rat hindlimb ischemia model. We tested the mitogenic activity of the scaffold’s degradation products using an in vitro assay and measured increased proliferation rates of smooth muscle cells and skeletal myoblasts compared to collagen. In a rat hindlimb ischemia model, the femoral artery was ligated and resected, followed by injection of 150 µL of skeletal muscle matrix or collagen 1 week post-injury. We demonstrate that the skeletal muscle matrix increased arteriole and capillary density, as well as recruited more desmin-positive and MyoD-positive cells compared to collagen. Our results indicate that this tissue-specific injectable hydrogel may be a potential therapy for treating ischemia related to PAD, as well as have potential beneficial effects on restoring muscle mass that is typically lost in CLI.
Matrix Metalloproteinase-2 Promoter Genotype as a Marker of Cutaneous T-Cell Lymphoma Early Stage
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Anna Vasku
2010-01-01
Full Text Available The aim of the study was to investigate the DNA polymorphic genotype in MMP-2 promoter gene as a potential candidate region for the development of the cutaneous T-cell lymphoma (CTCL and/or its progression. A total of 89 Czech patients with CTCL (including 23 patients with large plaque parapsoriasis were compared to 198 controls of similar age and sex distribution, without personal or family history of chronic skin diseases and without personal history of malignancy. The three selected polymorphisms in the promoter of MMP-2 gene (−1575G/A, −1306C/T, and −790T/G were determined using the PCR-based methodology with RFLP. In our cohort, the associated GGCCTT MMP-2 promoter genotype was highly significantly more frequent in CTCL-Ia stage patients compared to patients with parapsoriasis, the tests having high sensitivity and specificity (78%, 83%, resp.. To conclude, use of associated MMP-2 promoter genotype as a DNA marker might make it possible to distinguish between the patients with parapsoriasis and those with CTCL stage Ia, which could substantially improve possibilities of clinical diagnostics, therapy design, and prognosis of this serious condition in the early stages.
Matrix metalloproteinase-2 promoter genotype as a marker of cutaneous T-cell lymphoma early stage.
Vasku, Anna; Vasku, Julie Bienertova; Necas, Miroslav; Vasku, Vladimir
2010-01-01
The aim of the study was to investigate the DNA polymorphic genotype in MMP-2 promoter gene as a potential candidate region for the development of the cutaneous T-cell lymphoma (CTCL) and/or its progression. A total of 89 Czech patients with CTCL (including 23 patients with large plaque parapsoriasis) were compared to 198 controls of similar age and sex distribution, without personal or family history of chronic skin diseases and without personal history of malignancy. The three selected polymorphisms in the promoter of MMP-2 gene (-1575G/A, -1306C/T, and -790T/G) were determined using the PCR-based methodology with RFLP. In our cohort, the associated GGCCTT MMP-2 promoter genotype was highly significantly more frequent in CTCL-Ia stage patients compared to patients with parapsoriasis, the tests having high sensitivity and specificity (78%, 83%, resp.). To conclude, use of associated MMP-2 promoter genotype as a DNA marker might make it possible to distinguish between the patients with parapsoriasis and those with CTCL stage Ia, which could substantially improve possibilities of clinical diagnostics, therapy design, and prognosis of this serious condition in the early stages.
Matrix Metalloproteinase-2 Promoter Genotype as a Marker of Cutaneous T-Cell Lymphoma Early Stage
Anna Vasku; Julie Bienertova Vasku; Miroslav Nečas; Vladimir Vasku
2010-01-01
The aim of the study was to investigate the DNA polymorphic genotype in MMP-2 promoter gene as a potential candidate region for the development of the cutaneous T-cell lymphoma (CTCL) and/or its progression. A total of 89 Czech patients with CTCL (including 23 patients with large plaque parapsoriasis) were compared to 198 controls of similar age and sex distribution, without personal or family history of chronic skin diseases and without personal history of malignancy. The three selected poly...
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Jessica L. Ungerleider, BS
2016-01-01
Full Text Available Although surgical and endovascular revascularization can be performed in peripheral arterial disease (PAD, 40% of patients with critical limb ischemia do not have a revascularization option. This study examines the efficacy and mechanisms of action of acellular extracellular matrix-based hydrogels as a potential novel therapy for treating PAD. We tested the efficacy of using a tissue-specific injectable hydrogel derived from decellularized porcine skeletal muscle (SKM and compared this to a new human umbilical cord-derived matrix (hUC hydrogel, which could have greater potential for tissue regeneration because of the younger age of the tissue source. In a rodent hindlimb ischemia model, both hydrogels were injected 1-week post-surgery and perfusion was regularly monitored with laser speckle contrast analysis to 35 days post-injection. There were significant improvements in hindlimb tissue perfusion and perfusion kinetics with both biomaterials. Histologic analysis indicated that the injected hydrogels were biocompatible, and resulted in arteriogenesis, rather than angiogenesis, as well as improved recruitment of skeletal muscle progenitors. Skeletal muscle fiber morphology analysis indicated that the muscle treated with the tissue-specific SKM hydrogel more closely matched healthy tissue morphology. Whole transcriptome analysis indicated that the SKM hydrogel caused a shift in the inflammatory response, decreased cell death, and increased blood vessel and muscle development. These results show the efficacy of an injectable ECM hydrogel alone as a potential therapy for treating patients with PAD. Our results indicate that the SKM hydrogel improved functional outcomes through stimulation of arteriogenesis and muscle progenitor cell recruitment.
Matrix-Gla protein promotes osteosarcoma lung metastasis and associates with poor prognosis.
Zandueta, Carolina; Ormazábal, Cristina; Perurena, Naiara; Martínez-Canarias, Susana; Zalacaín, Marta; Julián, Mikel San; Grigoriadis, Agamemnon E; Valencia, Karmele; Campos-Laborie, Francisco J; Rivas, Javier De Las; Vicent, Silvestre; Patiño-García, Ana; Lecanda, Fernando
2016-08-01
Osteosarcoma (OS) is the most prevalent osseous tumour in children and adolescents and, within this, lung metastases remain one of the factors associated with a dismal prognosis. At present, the genetic determinants driving pulmonary metastasis are poorly understood. We adopted a novel strategy using robust filtering analysis of transcriptomic profiling in tumour osteoblastic cell populations derived from human chemo-naive primary tumours displaying extreme phenotypes (indolent versus metastatic) to uncover predictors associated with metastasis and poor survival. We identified MGP, encoding matrix-Gla protein (MGP), a non-collagenous matrix protein previously associated with the inhibition of arterial calcification. Using different orthotopic models, we found that ectopic expression of Mgp in murine and human OS cells led to a marked increase in lung metastasis. This effect was independent of the carboxylation of glutamic acid residues required for its physiological role. Abrogation of Mgp prevented lung metastatic activity, an effect that was rescued by forced expression. Mgp levels dramatically altered endothelial adhesion, trans-endothelial migration in vitro and tumour cell extravasation ability in vivo. Furthermore, Mgp modulated metalloproteinase activities and TGFβ-induced Smad2/3 phosphorylation. In the clinical setting, OS patients who developed lung metastases had high serum levels of MGP at diagnosis. Thus, MGP represents a novel adverse prognostic factor and a potential therapeutic target in OS. Microarray datasets may be found at: http://bioinfow.dep.usal.es/osteosarcoma/ Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Atkinson, Stuart P.; Quiñonero, Alicia; Martínez, Sebastián; Pellicer, Antonio; Simón, Carlos
2012-01-01
Invasion of the trophoblast into the maternal decidua is regulated by both the trophoectoderm and the endometrial stroma, and entails the action of tissue remodeling enzymes. Trophoblast invasion requires the action of metalloproteinases (MMPs) to degrade extracellular matrix (ECM) proteins and in turn, decidual cells express tissue inhibitors of MMPs (TIMPs). The balance between these promoting and restraining factors is a key event for the successful outcome of pregnancy. Gene expression is post-transcriptionally regulated by histone deacetylases (HDACs) that unpacks condensed chromatin activating gene expression. In this study we analyze the effect of histone acetylation on the expression of tissue remodeling enzymes and activity of human endometrial stromal cells (hESCs) related to trophoblast invasion control. Treatment of hESCs with the HDAC inhibitor trichostatin A (TSA) increased the expression of TIMP-1 and TIMP-3 while decreased MMP-2, MMP-9 and uPA and have an inhibitory effect on trophoblast invasion. Moreover, histone acetylation is detected at the promoters of TIMP-1 and TIMP-3 genes in TSA-treated. In addition, in an in vitro decidualized hESCs model, the increase of TIMP-1 and TIMP-3 expression is associated with histone acetylation at the promoters of these genes. Our results demonstrate that histone acetylation disrupt the balance of ECM modulators provoking a restrain of trophoblast invasion. These findings are important as an epigenetic mechanism that can be used to control trophoblast invasion. PMID:22291969
PACAP Promotes Matrix-Driven Adhesion of Cultured Adult Murine Neural Progenitors
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James A. Waschek
2017-05-01
Full Text Available New neurons are born throughout the life of mammals in germinal zones of the brain known as neurogenic niches: the subventricular zone of the lateral ventricles and the subgranular zone of the dentate gyrus of the hippocampus. These niches contain a subpopulation of cells known as adult neural progenitor cells (aNPCs, which self-renew and give rise to new neurons and glia. aNPCs are regulated by many factors present in the niche, including the extracellular matrix (ECM. We show that the neuropeptide PACAP (pituitary adenylate cyclase-activating polypeptide affects subventricular zone-derived aNPCs by increasing their surface adhesion. Gene array and reconstitution assays indicate that this effect can be attributed to the regulation of ECM components and ECM-modifying enzymes in aNPCs by PACAP. Our work suggests that PACAP regulates a bidirectional interaction between the aNPCs and their niche: PACAP modifies ECM production and remodeling, in turn the ECM regulates progenitor cell adherence. We speculate that PACAP may in this manner help restrict adult neural progenitors to the stem cell niche in vivo, with potential significance for aNPC function in physiological and pathological states.
Su, Yu-Ching; Mukherjee, Oindrilla; Singh, Birendra; Hallgren, Oskar; Westergren-Thorsson, Gunilla; Hood, Derek; Riesbeck, Kristian
2016-01-15
Interaction with the extracellular matrix (ECM) is one of the successful colonization strategies employed by nontypeable Haemophilus influenzae (NTHi). Here we identified Haemophilus lipoprotein e (P4) as a receptor for ECM proteins. Purified recombinant P4 displayed a high binding affinity for laminin (Kd = 9.26 nM) and fibronectin (Kd = 10.19 nM), but slightly less to vitronectin (Kd = 16.51 nM). A P4-deficient NTHi mutant showed a significantly decreased binding to these ECM components. Vitronectin acquisition conferred serum resistance to both P4-expressing NTHi and Escherichia coli transformants. P4-mediated bacterial adherence to pharynx, type II alveolar, and bronchial epithelial cells was mainly attributed to fibronectin. Importantly, a significantly reduced bacterial infection was observed in the middle ear of the Junbo mouse model when NTHi was devoid of P4. In conclusion, our data provide new insight into the role of P4 as an important factor for Haemophilus colonization and subsequent respiratory tract infection.
Association between promoter polymorphisms of matrix metalloproteinase-1 and risk of gastric cancer.
Peng, Qisong; Xu, Yong
2015-01-01
Growing evidences show that matrix metalloproteinase-1 (MMP1) plays important roles in tumorigenesis and cancer metastasis. The interactions between MMP1-1607 1G>2G polymorphism and risk of gastric cancer (GC) have been reported, but results remained ambiguous. To determine the association between MMP1-1607 1G>2G polymorphism and risk of GC, we conducted a meta-analysis and identified the outcome data from all the research papers estimating the association between MMP1-1607 1G>2G polymorphism and GC risk, which was based on comprehensive searches using databases such as PubMed, Elsevier Science Direct, Excerpta Medica Database (EMBASE), and Chinese National Knowledge Infrastructure (CNKI). The fixed-effects model was used in this meta-analysis. Data were extracted, and pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. In this meta-analysis, six studies involving 1,377 cases and 1,543 controls were included. We identified the significant association between MMP1-1607 1G>2G polymorphism and GC risk for allele model (OR =1.05; 95% CI, 1.01-1.08), for dominant model (OR =1.11; 95% CI, 1.08-1.15), and for recessive model (OR =1.06; 95% CI, 0.98-1.14). In summary, our analysis demonstrated that MMP1-1607 1G>2G polymorphism was significantly associated with an increased risk of GC.
Ham, Sun Ah; Kim, Hyo Jung; Kim, Hyun Joon; Kang, Eun Sil; Eun, So Young; Kim, Gil Hyeong; Park, Myung Hyun; Woo, Im Sun; Kim, Hye Jung; Chang, Ki Churl; Lee, Jae Heun; Seo, Han Geuk
2010-06-01
Although the peroxisome proliferator-activated receptor (PPAR) delta has been implicated in the wound healing process, its exact role and mechanism of action have not been fully elucidated. Our previous findings showed that PPARdelta induces the expression of the transforming growth factor (TGF)-beta1, which has been implicated in the deposit of extracellular matrix proteins. Here, we demonstrate that administration of GW501516, a specific PPARdelta ligand, significantly promoted wound closure in the experimental mouse and had a profound effect on the expression of collagen types I and III, alpha-smooth muscle actin, pSmad3 and TGF-beta1, which play a pivotal role in wound healing processes. Activation of PPARdelta increased migration of human epidermal keratinocytes and dermal fibroblasts in in vitro scrape-wounding assays. Addition of a specific ALK5 receptor inhibitor SB431542 significantly suppressed GW501516-induced migration of human keratinocytes and fibroblasts. In these cells, activated PPARdelta also induced the expression of collagen types I and III and fibronectin in a TGF-beta1-dependent or -independent manner. The effect of PPARdelta on the expression of type III collagen was dually regulated by the direct binding of PPARdelta and Smad3 to a direct repeat-1 site and a Smad-binding element, respectively, of the type III gene promoter. Taken together, these results demonstrated that PPARdelta plays an important role in skin wound healing in vivo and that it functions by accelerating extracellular matrix-mediated cellular interactions in a process mediated by the TGF-beta1/Smad3 signaling-dependent or - independent pathway.
He, Hongliang; Liu, Xiaozhen; Peng, Liang; Gao, Zhiliang; Ye, Yun; Su, Yujie; Zhao, Qiyi; Wang, Ke; Gong, Yihong; He, Fan
2013-01-01
Interactions between stem cells and extracellular matrix (ECM) are requisite for inducing lineage-specific differentiation and maintaining biological functions of mesenchymal stem cells by providing a composite set of chemical and structural signals. Here we investigated if cell-deposited ECM mimicked in vivo liver's stem cell microenvironment and facilitated hepatogenic maturation. Decellularization process preserved the fibrillar microstructure and a mix of matrix proteins in cell-deposited ECM, such as type I collagen, type III collagen, fibronectin, and laminin that were identical to those found in native liver. Compared with the cells on tissue culture polystyrene (TCPS), bone marrow mesenchymal stem cells (BM-MSCs) cultured on cell-deposited ECM showed a spindle-like shape, a robust proliferative capacity, and a suppressed level of intracellular reactive oxygen species, accompanied with upregulation of two superoxide dismutases. Hepatocyte-like cells differentiated from BM-MSCs on ECM were determined with a more intensive staining of glycogen storage, an elevated level of urea biosynthesis, and higher expressions of hepatocyte-specific genes in contrast to those on TCPS. These results demonstrate that cell-deposited ECM can be an effective method to facilitate hepatic maturation of BM-MSCs and promote stem-cell-based liver regenerative medicine.
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Hongliang He
2013-01-01
Full Text Available Interactions between stem cells and extracellular matrix (ECM are requisite for inducing lineage-specific differentiation and maintaining biological functions of mesenchymal stem cells by providing a composite set of chemical and structural signals. Here we investigated if cell-deposited ECM mimicked in vivo liver's stem cell microenvironment and facilitated hepatogenic maturation. Decellularization process preserved the fibrillar microstructure and a mix of matrix proteins in cell-deposited ECM, such as type I collagen, type III collagen, fibronectin, and laminin that were identical to those found in native liver. Compared with the cells on tissue culture polystyrene (TCPS, bone marrow mesenchymal stem cells (BM-MSCs cultured on cell-deposited ECM showed a spindle-like shape, a robust proliferative capacity, and a suppressed level of intracellular reactive oxygen species, accompanied with upregulation of two superoxide dismutases. Hepatocyte-like cells differentiated from BM-MSCs on ECM were determined with a more intensive staining of glycogen storage, an elevated level of urea biosynthesis, and higher expressions of hepatocyte-specific genes in contrast to those on TCPS. These results demonstrate that cell-deposited ECM can be an effective method to facilitate hepatic maturation of BM-MSCs and promote stem-cell-based liver regenerative medicine.
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Jamal Stie
Full Text Available BACKGROUND: The fungal pathogen Cryptococcus neoformans is a leading cause of illness and death in persons with predisposing factors, including: malignancies, solid organ transplants, and corticosteroid use. C. neoformans is ubiquitous in the environment and enters into the lungs via inhalation, where it can disseminate through the bloodstream and penetrate the central nervous system (CNS, resulting in a difficult to treat and often-fatal infection of the brain, called meningoencephalitis. Plasminogen is a highly abundant protein found in the plasma component of blood and is necessary for the degradation of fibrin, collagen, and other structural components of tissues. This fibrinolytic system is utilized by cancer cells during metastasis and several pathogenic species of bacteria have been found to manipulate the host plasminogen system to facilitate invasion of tissues during infection by modifying the activation of this process through the binding of plasminogen at their surface. METHODOLOGY: The invasion of the brain and the central nervous system by penetration of the protective blood-brain barrier is a prerequisite to the establishment of meningoencephalitis by the opportunistic fungal pathogen C. neoformans. In this study, we examined the ability of C. neoformans to subvert the host plasminogen system to facilitate tissue barrier invasion. Through a combination of biochemical, cell biology, and proteomic approaches, we have shown that C. neoformans utilizes the host plasminogen system to cross tissue barriers, providing support for the hypothesis that plasminogen-binding may contribute to the invasion of the blood-brain barrier by penetration of the brain endothelial cells and underlying matrix. In addition, we have identified the cell wall-associated proteins that serve as plasminogen receptors and characterized both the plasminogen-binding and plasmin-activation potential for this significant human pathogen. CONCLUSIONS: The results of
Kawal, Priyanka; Chandra, Anil; Rajkumar; Dhole, Tapan N.; Ojha, Balkrishna
2016-01-01
Background: Oligodendrogliomas are infiltrative astrocytic tumors. They constitute about 1-5% of intracranial tumors. These have been graded into benign and malignant grades. The single nucleotide polymorphisms (SNPs) in the promoter regions of MMP genes may influence tumor development and progression. This study was done to explore the correlations of the promoter SNPs in MMP-1, MMP-2 and MMP-7 genes susceptibility in development and progression of oligodendrogliomas. Objectives: We aimed to investigate the association of MMP1 (−1607A > G), MMP-2 (−1306 C/T) and MMP-7(−181A > G) gene polymorphism in oligodendrogliomas (grade I, II, III). Materials and Methods: In the present case control study, we enrolled a total of 30 cases of oligodendrogliomas (grade I to III) confirmed by histopathology and 30 healthy cases as control. Polymorphism for MMP-1 gene (−1607A > G), MMP-2 (−1306 C/T), MMP-7(−181A > G) were genotyped by restriction fragment length polymorphism. Results: Frequencies of MMP-1 (−1607A > G) genotypes and 2G alleles were significantly associated with the cases of oligodendrogliomas (30%) in relation to healthy controls (13%). [OR = 6.89; P = 0.02; 95%CI= (1.33-35.62)] and [OR = 2.66; P =0.01; 95% CI= (1.26-5.64)]. A significant association of MMP-2 (−1306C/T) polymorphism with oligodendroglioma (P = 0.54) was not found, suggesting that MMP-2 (−1306C/T) polymorphism is not associated with increased oligodendroglioma susceptibility. Frequencies of MMP-7(−181A > G) genotypes and 2G alleles were significantly associated with the cases of oligodendrogliomas (33.33%) in relation to healthy controls (13.33%). [OR = 5.65; P = 0.02; 95%CI= (1.26-25.36)] and [OR = 2.49; P =0.01; 95% CI= (1.17-5.27)]. Conclusions: MMP-1 (−1607 A > G), MMP-7(−181A > G) genotypes and 2G alleles were significantly associated with oligodendroglioma (grade I, II, III), but MMP-2 (−1306C/T) polymorphism is not associated with increased oligodendroglioma
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Thomas Bertero
2015-11-01
Full Text Available Pulmonary hypertension (PH is a deadly vascular disease with enigmatic molecular origins. We found that vascular extracellular matrix (ECM remodeling and stiffening are early and pervasive processes that promote PH. In multiple pulmonary vascular cell types, such ECM stiffening induced the microRNA-130/301 family via activation of the co-transcription factors YAP and TAZ. MicroRNA-130/301 controlled a PPARγ-APOE-LRP8 axis, promoting collagen deposition and LOX-dependent remodeling and further upregulating YAP/TAZ via a mechanoactive feedback loop. In turn, ECM remodeling controlled pulmonary vascular cell crosstalk via such mechanotransduction, modulation of secreted vasoactive effectors, and regulation of associated microRNA pathways. In vivo, pharmacologic inhibition of microRNA-130/301, APOE, or LOX activity ameliorated ECM remodeling and PH. Thus, ECM remodeling, as controlled by the YAP/TAZ-miR-130/301 feedback circuit, is an early PH trigger and offers combinatorial therapeutic targets for this devastating disease.
Huang, Sheng-Fu; Li, Yu-Hong; Ren, Yi-Jin; Cao, Zheng-Guo; Long, Xing
2008-01-01
Matrix metalloproteinase-1 (MMP-1) 1G/2G (-1,607) polymorphisms have been identified and shown to influence the transcription of the MMP-1 gene. In order to compare the expression of MMP-1 with different MMP-1 gene promoter alleles after force loading, human periodontal ligament (PDL) cells were cul
Srivastava, Priyanka; Kapoor, Rakesh; Mittal, Rama D
2013-02-01
Matrix metalloproteinases (MMPs) are expressed in melanocytes and their overexpression has been linked to tumor development, progression, and metastasis. At the genetic level, following functional promoter polymorphisms are known to modify the gene transcription: -1306 C > T, -735 C > T in MMP2, and 799 C > T in MMP8 gene. Hence we hypothesize that functional polymorphisms in the 2 MMP SNPs in promoter region may modulate the risk for bladder cancer (BC) progression in North Indian population. Genotyping for these polymorphisms were done in a group of 200 BC and 200 age matched, similar ethnicity unrelated healthy controls using PCR-based methods. Two-sided χ(2), Cox-regression was utilized to evaluate the associations between genotype and various clinical and epidemiologic factors. Multivariate analyses were conducted using logistic regression, adjusting for known BC confounders such as age and gender. Survival analysis was done using the Kaplan-Meier method and differences in survival were assessed using the log rank test. Individuals with MMP2 (-1306) TT genotype as well as T allele were at higher risk of BC (P, 0.042; OR, 2.85; P, 0.001; OR, 1.76). This effect was even more apparent in case of CT+TT (P T were associated with high risk of recurrence in BCG treated patients (HR, 4.32; P, 0.006 and HR, 2.06; P, 0.047) thus showing reduced recurrence free survival (CT+TT/CC = 34/45 months; log rank P, 0.039). Our data suggested that variant allele of MMP2 1306C > T was associated with high risk of tumor recurrence and reduced recurrence free survival in superficial BC patients. Copyright © 2013 Elsevier Inc. All rights reserved.
Ohnishi, Yu-Ichiro; Iwatsuki, Koichi; Ishihara, Masahiro; Ohkawa, Toshika; Kinoshita, Manabu; Shinzawa, Koei; Fujimoto, Yasunori; Yoshimine, Toshiki
2017-03-01
OBJECTIVE Diffuse astrocytomas (DAs) have a high recurrence rate due to diffuse infiltration into the brain and spinal cord. Micro RNAs (miRNAs) are small noncoding RNAs that regulate gene expression by binding to complementary sequences of target messenger RNA (mRNA). It has been reported that miRNA-22 (miR-22) is involved in the invasion of some cancer cell lines. The aim of this study was to identify the biological effects of miR-22 in regard to the invasion of human DAs. METHODS The authors evaluated whether the level of miR-22 is elevated in human spinal DAs by using miRNA chips. Next, the role of miR-22 in 1321N1 human astrocytoma cells was investigated. Finally, to elucidate whether miR-22 promotes invasion by astrocytoma cells in vivo, the authors transplanted miR-22 overexpressed astrocytoma cells into mouse thoracic spinal cord. RESULTS The miR-22 significantly upregulated the invasion capacity of 1321N1 cells. Computational in silico analysis predicted that tissue inhibitor of matrix metalloproteinase-2 (TIMP2) is a target gene of miR-22. This was confirmed by quantitative reverse transcription polymerase chain reaction and Western blotting, which showed that miR-22 inhibited TIMP2 mRNA and protein expression, respectively. Luciferase reporter assays demonstrated that miR-22 directly bound the 3'-untranslated regions of TIMP2. The authors further showed that miR-22 promoted invasiveness in 1321N1 astrocytoma cells when transplanted into mouse spinal cord. CONCLUSIONS These data suggest that miR-22 acts to regulate invasion of 1321N1 astrocytoma cells by targeting TIMP2 expression. Additional studies with more cases and cell lines are required to elucidate the findings of this study for a novel treatment target for spinal DAs.
Suzuki, Hideo; Sasada, Manabu; Kamiya, Sadahiro; Ito, Yuka; Watanabe, Hikaru; Okada, Yuko; Ishibashi, Kazuma; Iyoda, Takuya; Yanaka, Akinori; Fukai, Fumio
2017-01-01
The extracellular matrix (ECM) molecule tenascin C (TNC) is known to be highly expressed under various pathological conditions such as inflammation and cancer. It has been reported that the expression of TNC is correlated with the malignant potential of cancer. In our laboratory, it was found that the peptide derived from the alternative splicing domain A2 in TNC, termed TNIIIA2, has been shown to influence a variety of cellular processes, such as survival, proliferation, migration, and differentiation. In this study, we investigated the effect of TNC/TNIIIA2 on the invasion and metastasis of colon cancer cells, Colon26-M3.1, or PMF-Ko14, using an in vitro and in vivo experimental system. The degree of cell invasion was increased by the addition of TNC and TNIIIA2 in a dose-dependent manner. The invasion by TNC and TNIIIA2 were suppressed by an MMP inhibitor or TNIIIA2-blocking antibody. In an in vivo experiment, pulmonary metastasis was promoted conspicuously by the addition of TNIIIA2. In this study, we found that colon cancer cell invasion and metastasis was accelerated by TNC/TNIIIA2 via MMP induction. This result suggests the possibility of a new strategy targeting TNC/TNIIIA2 for colon cancer. PMID:28106752
Tsuru, A; Setoguchi, T; Matsunoshita, Y; Nagao-Kitamoto, H; Nagano, S; Yokouchi, M; Maeda, S; Ishidou, Y; Yamamoto, T; Komiya, S
2015-03-31
Activation of the Notch pathway has been reported in various types of cancers. However, the role of the hairy/enhancer-of-split related with YRPW motif protein 1 (HEY1) in osteosarcoma is unknown. We examined the function of HEY1 in osteosarcoma. Expression of HEY1 was studied in human osteosarcoma. The effects of HEY1 in osteosarcoma were evaluated in vitro and in a xenograft model. Moreover, we examined the function of matrix metallopeptidase 9 (MMP9) as a downstream effector of HEY1. HEY1 was upregulated in human osteosarcoma. Knockdown of HEY1 inhibited the invasion of osteosarcoma cell lines. In contrast, the forced expression of HEY1 increased the invasion of mesenchymal stem cell. In addition, lung metastases were significantly inhibited by the knockdown of HEY1. We found that MMP9 was a downstream effector of HEY1 that promotes the invasion of osteosarcoma cells. Knockdown of HEY1 decreased the expression of MMP9. Addition of MMP9 rescued the invasion of osteosarcoma cells that had been rendered less invasive by knockdown of HEY1 expression. Our findings suggested that HEY1 augmented the metastasis of osteosarcoma via upregulation of MMP9 expression. Therefore, inhibition of HEY1 may be a novel therapeutic strategy for preventing osteosarcoma metastasis.
Indian Academy of Sciences (India)
HUI YE; YAZHOU HE; JIARONG WANG; TIANGE SONG; ZHU LAN; YIQI ZHAO; MINGRONG XI
2016-09-01
Matrix metalloproteinase (MMP) promoter polymorphisms are considered to play roles in the aetiology of endometriosis and adenomyosis, however, the evidence available are inconsistent. We aimed to systematically review the asscociationbetween MMP-1 -1607 1G/2G MMP-2 -735 C/T, MMP-3 -1171 5A/6A and MMP-9 -1562 C/T polymorphisms and the risk of endometriosis and adenomyosis. A systemic search was conducted in Ovid, PubMed, Chinese National Knowledge Infrastructure and Chinese Wanfang Database. We used the pooled odds ratio (OR) and their corresponding 95% confidence interval (CI) to calculate the statistical power. Besides, we evaluated the quality of individual studies based on Newcastle–Ottawa scale. A total of 13 papers with 18 studies conformed to our inclusion criteria. We observed a significant association betweenMMP-1 -1607 1G/2G polymorphism and the susceptibility of endometriosis and adenomyosis under recessive model (OR =1.25, 95%CI = 1.03–1.53,P=0.03). While no significant association was found in MMP-2 -735 C/T, MMP-3 -1171 5A/6A and MMP-9 -1562 C/T polymorphisms. This systemic review and meta-analysis suggested that the MMP-1 -1607 1G/2G polymorphism might play an important role in the risk of endometriosis and adenomyosis. Further, more well-designed and large-scale studies regarding gene–gene and gene–environment interactions are needed in the future.
Institute of Scientific and Technical Information of China (English)
ChunyuanYu; YifengZhou; XiaopingMiao; PingXiong; WenTan; DongxinLin
2005-01-01
Matrix metalloproteinase-2 (MMP-2) plays important roles in cancer development and aggression. Our previous studies revealed a strong association between the MMP-2 -1306C/T polymorphism and risk of several cancers. A novel -735C/T polymorphism in MMP-2 promoter has been identified but the function is undefined. This study examined our hypothesis that these two polymorphisms might have functional relevance and impact on risk of esophageal squamous cell carcinoma in the context of haplotype. Genotypes and haplotypes were analyzed in 527 cases and 777 controls and odds ratios (ORs) and 95% confidence intervals (CIs)were estimated by logistic regression. The function of the polymorphisms was examined by electrophoretic mobility shift assays, luciferase gene expression assays, and reverse transcriptase-PCR analyses. It was found that the -735C→T transition disrupts an Spl site and displays a lowerpromoter activity. The C_1306-C-735 haplotype had 7-fold increased luciferase expression and 3.7-fold increased MMPo2 mRNA levels in esopha-gcal tissues compared with the T-1306-T-735 haplotype. A case-control analysis revealed a 1.52-fold (95% CI=1.17-1.96) or 1.30-fold (95%CI = 1.04-1.63) excess risk of developing esophageal squamous cell carcinoma for the -1306CC or -735CC genotype carriers compared with noncarriers, respectively. A greater association was observed between elevated risk of developing esophageal squamous cell carcinoma andC-1306 or C-735 allele containing haplotypes, with the risk being highest for the C-1306-C-735 haplotype compared with the T-1306-T-735 haplotype(OR = 6.53; 95% CI = 2.78-15.33). The C-1306-C-735 haplotype was also associated with increased risk for distant metastasis of esophageal squamous cell carcinoma (OR = 3.34; 95% CI = 1.16-9.63). These findings suggest that the C-1306-C-735 haplotype in the MMpo2 promoter contributes to risk of the occurrence and metastasis of esophageal squamous cell carcinoma by increasing expression of MMP-2.
Shi, Jiajia; Sun, Jie; Zhang, Wen; Liang, Hui; Shi, Qin; Li, Xiaoran; Chen, Yanyan; Zhuang, Yan; Dai, Jianwu
2016-10-07
The reconstruction of bone usually depends on substitute transplantation, which has drawbacks including the limited bone substitutes available, comorbidity, immune rejection, and limited endogenous bone regeneration. Here, we constructed a functionalized bone substitute by combining application of the demineralized bone matrix (DBM) and collagen-binding stromal-cell-derived factor-1α (CBD-SDF-1α). DBM was a poriferous and biodegradable bone substitute, derived from bovine bone and consisting mainly of collagen. CBD-SDF-1α could bind to collagen and be controllably released from the DBM to mobilize stem cells. In a rat femur defect model, CBD-SDF-1α-modified DBM scaffolds could efficiently mobilize CD34(+) and c-kit(+) endogenous stem cells homing to the injured site at 3 days after implantation. According to the data from micro-CT, CBD-SDF-1α-modified DBM scaffolds could help the bone defects rejoin with mineralization accumulated and bone volume expanded. Interestingly, osteoprotegerin (OPG) and osteopontin (OPN) were highly expressed in CBD-SDF-1α group at an early time after implantation, while osteocalcin (OCN) was more expanded. H&E and Masson's trichrome staining showed that the CBD-SDF-1α-modified DBM scaffold group had more osteoblasts and that the bone defect rejoined earlier. The ultimate strength of the regenerated bone was investigated by three-point bending, showing that the CBD-SDF-1α group had superior strength. In conclusion, CBD-SDF-1α-modified DBM scaffolds could promote bone regeneration by recruiting endogenous stem cells.
Ray, Amlan K.; DasMahapatra, Pramathes; Swarnakar, Snehasikta
2016-01-01
Endometriosis is characterized by the ectopic development of the endometrium which relies on angiogenesis. Although studies have identified the involvement of different matrix metalloproteinases (MMPs) in endometriosis, no study has yet investigated the role of MMP-2 in endometriosis-associated angiogenesis. The present study aims to understand the regulation of MMP-2 activity in endothelial cells and on angiogenesis during progression of ovarian endometriosis. Histological and biochemical data showed increased expressions of vascular endothelial growth factor (VEGF), VEGF receptor-2, cycloxygenase (COX)-2, von Willebrand factor along with angiogenesis during endometriosis progression. Women with endometriosis showed decreased MMP-2 activity in eutopic endometrium as compared to women without endometriosis. However, ectopic ovarian endometrioma showed significantly elevated MMP-2 activity with disease severity. In addition, increased MT1MMP and decreased tissue inhibitors of metalloproteinases (TIMP)-2 expressions were found in the late stages of endometriosis indicating more MMP-2 activation with disease progression. In vitro study using human endothelial cells showed that prostaglandin E2 (PGE2) significantly increased MMP-2 activity as well as tube formation. Inhibition of COX-2 and/or phosphorylated AKT suppressed MMP-2 activity and endothelial tube formation suggesting involvement of PGE2 in regulation of MMP-2 activity during angiogenesis. Moreover, specific inhibition of MMP-2 by chemical inhibitor significantly reduced cellular migration, invasion and tube formation. In ovo assay showed decreased angiogenic branching upon MMP-2 inhibition. Furthermore, a significant reduction of lesion numbers was observed upon inhibition of MMP-2 and COX-2 in mouse model of endometriosis. In conclusion, our study establishes the involvement of MMP-2 activity via COX-2-PGE2-pAKT axis in promoting angiogenesis during endometriosis progression. PMID:27695098
González-Santamaría, J.; Villalba, M.; Busnadiego, O.; López-Olañeta, M.M.; Sandoval, P.; Snabel, J.; López-Cabrera, M.; Erler, J.T.; Hanemaaijer, R.; Lara-Pezzi, E.; Rodríguez-Pascual, F.
2016-01-01
Aims After myocardial infarction (MI), extensive remodelling of the extracellular matrix contributes to scar formation. While aiming to preserve tissue integrity, this fibrotic response is also associated with adverse events, including a markedly increased risk of heart failure, ventricular arrhythm
DEFF Research Database (Denmark)
González-Santamaría, José; Villalba, María; Busnadiego, Oscar
2016-01-01
AIMS: After myocardial infarction (MI), extensive remodelling of the extracellular matrix contributes to scar formation. While aiming to preserve tissue integrity, this fibrotic response is also associated with adverse events, including a markedly increased risk of heart failure, ventricular arrh...
Institute of Scientific and Technical Information of China (English)
Wei Liao; Sanjai Sharma
2016-01-01
Objective: Chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL) cells over-express a guanine exchange factor (GEF), Rasgrf-1. This GEF increases active Ras as it catalyzes the removal of GDP from Ras so that GTP can bind and activate Ras. This study aims to study the mechanism of action of Rasgrf-1 in B-cell malignancies. Methods: N-terminus truncated Rasgrf-1 variants have a higher GEF activity as compared to the full-length transcript therefore a MCL cell line with stable over-expression of truncated Rasgrf-1 was established. The B-cell receptor (BCR) and chemokine signaling pathways were compared in the Rasgrf-1 over-expressing and a control transfected cell line. Results: Cells over-expressing truncated form of Rasgrf-1 have a higher proliferative rate as compared to control transfected cells. BCR was activated by lower concentrations of anti-IgM antibody in Rasgrf-1 over-expressing cells as compared to control cells indicating that these cells are more sensitive to BCR signaling. BCR signaling also phosphorylates Rasgrf-1 that further increases its GEF function and amplifies BCR signaling. This activation of Rasgrf-1 in over-expressing cells resulted in a higher expression of phospho-ERK, AKT, BTK and PKC-alpha as compared to control cells. Besides BCR, Rasgrf-1 over-expressing cells were also more sensitive to microenvironment stimuli as determined by resistance to apoptosis, chemotaxis and ERK pathway activation. Conclusions: This GEF protein sensitizes B-cells to BCR and chemokine mediated signaling and also upregulates a number of other signaling pathways which promotes growth and survival of these cells.
Pesch, Yanina-Yasmin; Riedel, Dietmar; Behr, Matthias
2015-01-01
Assembly and maturation of the apical extracellular matrix (aECM) is crucial for protecting organisms, but underlying molecular mechanisms remain poorly understood. Epidermal cells secrete proteins and enzymes that assemble at the apical cell surface to provide epithelial integrity and stability during developmental growth and upon tissue damage. We analyzed molecular mechanisms of aECM assembly and identified the conserved chitin-binding protein Obst-A (Obstructor A) as an essential regulator. We show in Drosophila that Obst-A is required to coordinate protein and chitin matrix packaging at the apical cell surface during development. Secreted by epidermal cells, the Obst-A protein is specifically enriched in the apical assembly zone where matrix components are packaged into their highly ordered architecture. In obst-A null mutant larvae, the assembly zone is strongly diminished, resulting in severe disturbance of matrix scaffold organization and impaired aECM integrity. Furthermore, enzymes that support aECM stability are mislocalized. As a biological consequence, cuticle architecture, integrity, and function are disturbed in obst-A mutants, finally resulting in immediate lethality upon wounding. Our studies identify a new core organizing center, the assembly zone that controls aECM assembly at the apical cell surface. We propose a genetically conserved molecular mechanism by which Obst-A forms a matrix scaffold to coordinate trafficking and localization of proteins and enzymes in the newly deposited aECM. This mechanism is essential for maturation and stabilization of the aECM in a growing and remodeling epithelial tissue as an outermost barrier. PMID:25737451
Vermeulen, Pieter; Dickens, Stijn; Degezelle, Karlien; Van den Berge, Stefaan; Hendrickx, Benoit; Vranckx, Jan Jeroen
2009-07-01
In search of an autologous vascularized skin substitute, we treated full-thickness wounds (FTWs) with autologous platelet-rich plasma gel (APG) in which we embedded endothelial progenitor cells (EPCs) and basal cell keratinocytes (KCs). We cultivated autologous KCs in low-serum conditions and expanded autologous EPCs from venous blood. FTWs (n = 55) were created on the backs of four pigs, covered with wound chambers, and randomly assigned to the following treatments: (1) APG, (2) APG + KCs, (3) APG + EPCs, (4) APG + KCs + EPCs, and (5) saline. All wounds were biopsied to measure neovascularization (lectin Bandeiraea Simplicifolia-1 (BS-1), alpha smooth muscle actin [alphaSMA], and membrane type 1 matrix metalloproteinase (MT1-MMP)), matrix deposition (fibronectin, collagen type I/III, and alphavbeta3), and reepithelialization. Wound fluids were analyzed for protein expression. All APG-treated wounds showed more vascular structures (p < 0.001), and the addition of EPCs further improved neovascularization, as confirmed by higher lectin, alphaSMA, and MT1-MMP. APG groups had higher collagen I/III (p < 0.05), alphavbeta3, and fibronectin content (p < 0.001), and they exhibited higher concentrations of platelet-derived growth factor subunit bb, basic fibroblast growth factor, hepatocyte growth factor, insulin growth factor-1, transforming growth factor-beta1 and -beta3, matrix metalloproteinase-1 and -z9, and tissue-inhibiting matrix metalloproteinase-1 and -2. Applying APG + KCs resulted in the highest reepithelialization rates (p < 0.001). No differences were found for wound contraction by planimetry. In this porcine FTW model, APG acts as a supportive biomatrix that, along with the embedded cells, improves extracellular matrix organization, promotes angiogenesis, and accelerates reepithelialization.
DEFF Research Database (Denmark)
Mirastschijski, Ursula; Schnabel, Reinhild; Claes, Juliane
2010-01-01
The ability to regulate wound contraction is critical for wound healing as well as for pathological contractures. Matrix metalloproteinases (MMPs) have been demonstrated to be obligatory for normal wound healing. This study examined the effect that the broad-spectrum MMP inhibitor BB-94 has when...... applied topically to full-thickness skin excisional wounds in rats and its ability to inhibit the promotion of myofibroblast formation and function by the latent transforming-growth factor-beta1 (TGF-beta1). BB-94 delayed wound contraction, as well as all other associated aspects of wound healing examined...... and may explain why wound contraction and other associated events of wound healing were only delayed and not completely inhibited. BB-94 was also found to inhibit the ability of latent TGF-beta1 to promote the formation and function of myofibroblasts. These results suggest that BB-94 could delay wound...
Udina, E; Ladak, A; Furey, M; Brushart, T; Tyreman, N; Gordon, T
2010-05-01
The inhibitory growth environment of myelin and extracellular matrix proteoglycans in the central nervous system may be overcome by elevating neuronal cAMP or degrading inhibitory proteoglycans with chondroitinase ABC (ChABC). In this study, we asked whether similar mechanisms operate in peripheral nerve regeneration where effective Wallerian degeneration removes myelin and extracellular proteoglycans slowly. We repaired transected common peroneal (CP) nerve in rats and either elevated cAMP in the axotomized neurons by subcutaneous rolipram, a specific inhibitor of phosphodiesterase IV, and/or promoted degradation of proteoglycans in the distal nerve stump by local ChABC administration. Rolipram treatment significantly increased the number of motoneurons that regenerated axons across the repair site at 1 and 2 weeks, and increased the number of sensory neurons that regenerated axons across the repair site at 2 weeks. Local application of ChABC had a similar effect to rolipram treatment in promoting motor axon regeneration, the effect being no greater when rolipram and ChABC were administered simultaneously. We conclude that blocking inhibitors of axon regeneration by elevating cAMP or degrading proteoglycans in the distal nerve stump promotes peripheral axon regeneration after surgical repair of a transected nerve. It is likely that elevated cAMP is sufficient to encourage axon outgrowth despite the inhibitory growth environment such that simultaneous enzymatic proteoglycan degradation does not promote more axon regeneration than either elevated cAMP or proteoglycan degradation alone.
Ben Néjima, Dalel; Ben Zarkouna, Yosr; Gammoudi, Amor; Manai, Mohamed; Boussen, Hamouda
2015-05-01
Matrix metalloproteinases (MMPs) are proteolytic enzymes that play important roles in tumor invasion and metastasis by degrading extracellular matrix components. Genetic variations in promoter regions of MMP genes, affecting their expression, have been associated with susceptibility to cancers. The aim of this study was to investigate the susceptibility and prognostic implications of the matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of metalloproteinase-2 (TIMP-2) polymorphism in Tunisian breast cancer patients. MMP-2 genotypes were determined by real-time polymerase chain reaction (RT-PCR), and TIMP-2 genotypes were identified using a PCR-restriction fragment length polymorphism (RFLP) method in 210 breast cancer patients and 250 frequency-matched control women. Association of the clinicopathological parameters and the genetic markers with risk of breast cancer was assessed using univariate analyses. We found that the variant MMP-2 genotype (-1306CT or TT) was associated with substantially reduced risk of breast cancer [odds ratio (OR), 0.49; 95 % confidence interval (95 % CI), 0.033-0.73], compared with the CC genotype. For TIMP-2, a moderately reduced risk of the cancer (OR, 0.57; 95 % CI, 0.37-0.87) was also associated with the variant allele (-418GC or CC), compared with the GG common allele. Furthermore, polymorphisms in both genes seem to have additive effects and the highest risk for breast cancer has been observed in those with MMP-2 CC genotype and TIMP-2 GC or CC genotype (p = 0.006). A significant association was also found between the CC genotype and the aggressive forms of breast cancer as defined by advanced stages at the time of diagnosis and metastasis. This is the first report on the association of MMP-2 and TIMP-2 gene polymorphisms in breast cancer in Tunisian population. Our results suggest that the presence of the variant allele in the promoter of MMP-2 or TIMP-2 may be a protective factor for the development of breast cancer.
Energy Technology Data Exchange (ETDEWEB)
Zhang Linglin; Zou Ling; Li Jiyao; Hao Yuqing; Xiao Liying; Zhou Xuedong; Li Wei, E-mail: leewei2000@sina.co, E-mail: zhll_sc@yahoo.c [State Key Laboratory of Oral Diseases, West China College of Stomatology, West China Hospital of Stomatology, Sichuan University, Chengdu (China)
2009-06-15
Galla chinensis, a natural traditional Chinese medicine with main composition of tannic acid and gallic acid, is formed when the Chinese sumac aphid Baker (Melaphis chinensis bell) parasitizes the levels of Rhus chinensis Mill. Galla chinensis has shown the potential to enhance the remineralization of initial enamel carious lesion, but the mechanism is still unknown. This study was to investigate whether the enamel organic matrix plays a significant role in the potential of Galla chinensis to promote the remineralization of initial enamel caries. Bovine sound enamel blocks and non-organic enamel blocks were demineralized and exposed to a 12 day pH cycling. During the pH cycling, 30 specimens with the enamel organic matrix were randomly divided into three groups, and treated with 1 g L{sup -1} NaF (group A), 4 g L{sup -1} Galla chinensis extract (group B1) or double deionized water (group C1). Twenty specimens without the enamel organic matrix were randomly divided into two groups, and treated with 4 g L{sup -1} Galla chinensis extract (group B2) or double deionized water (group C2). The integrated mineral loss and lesion depth of all the specimens were analysed by transverse microradiography. The integrated mineral loss and lesion depth of group B1 were less than those of groups B2, C1 and C2, and there were no statistical differences among groups B2, C1 and C2. In conclusion, Galla chinensis can enhance the remineralization of initial enamel carious lesion, and the enamel organic matrix plays a significant role in this potential of Galla chinensis.
Energy Technology Data Exchange (ETDEWEB)
Wang, Cheng-hu; Cao, Guo-Fan [The Affiliated Eye Hospital of Nanjing Medical University, Nanjing 210029 (China); Jiang, Qin, E-mail: Jqin710@vip.sina.com [The Affiliated Eye Hospital of Nanjing Medical University, Nanjing 210029 (China); Yao, Jin, E-mail: dryaojin@yahoo.com [The Affiliated Eye Hospital of Nanjing Medical University, Nanjing 210029 (China)
2012-08-17
Highlights: Black-Right-Pointing-Pointer TNF-{alpha} induces MMP-9 expression and secretion to promote RPE cell migration. Black-Right-Pointing-Pointer MAPK activation is not critical for TNF-{alpha}-induced MMP-9 expression. Black-Right-Pointing-Pointer Akt and mTORC1 signaling mediate TNF-{alpha}-induced MMP-9 expression. Black-Right-Pointing-Pointer SIN1 knockdown showed no significant effect on MMP-9 expression by TNF-{alpha}. -- Abstract: Tumor necrosis factor-alpha (TNF-{alpha}) promotes in vitro retinal pigment epithelial (RPE) cell migration to initiate proliferative vitreoretinopathy (PVR). Here we report that TNF-{alpha} promotes human RPE cell migration by inducing matrix metallopeptidase 9 (MMP-9) expression. Inhibition of MMP-9 by its inhibitor or its neutralizing antibody inhibited TNF-{alpha}-induced in vitro RPE cell migration. Reversely, exogenously-added active MMP-9 promoted RPE cell migration. Suppression Akt/mTOR complex 1(mTORC1) activation by LY 294002 and rapamycin inhibited TNF-{alpha}-mediated MMP-9 expression. To introduce a constitutively active Akt (CA-Akt) in cultured RPE cells increased MMP-9 expression, and to block mTORC1 activation by rapamycin inhibited its effect. RNA interference (RNAi)-mediated silencing of SIN1, a key component of mTOR complex 2 (mTORC2), had no effect on MMP-9 expression or secretion. In conclusion, this study suggest that TNF-{alpha} promotes RPE cell migration by inducing MMP-9 expression through activation of Akt/ mTORC1, but not mTORC2 signaling.
DEFF Research Database (Denmark)
Geng, Hui; Carlsen, Stefan; Nandakumar, Kutty;
2008-01-01
ABSTRACT: INTRODUCTION: Cartilage oligomeric matrix protein (COMP) is a homopentameric protein in cartilage. The development of arthritis, like collagen-induced arthritis (CIA), involves cartilage as a target tissue. We have investigated the development of CIA in COMP-deficient mice. METHODS: COMP......-deficient mice in the 129/Sv background were backcrossed for 10 generations against B10.Q mice, which are susceptible to chronic CIA. COMP-deficient and wild-type mice were tested for onset, incidence, and severity of arthritis in both the collagen and collagen antibody-induced arthritis models. Serum anti......-collagen II and anti-COMP antibodies as well as serum COMP levels in arthritic and wild-type mice were measured by enzyme-linked immunosorbent assay. RESULTS: COMP-deficient mice showed a significant early onset and increase in the severity of CIA in the chronic phase, whereas collagen II-antibody titers were...
Energy Technology Data Exchange (ETDEWEB)
Alves, Tercia Rodrigues [Universidade do Estado do Rio de Janeiro (UERJ), Instituto de Biologia Roberto Alcantara Gomes, Departamento de Biologia Celular, Laboratorio de Biologia da Celula Endotelial e da Angiogenese (LabAngio), Rio de Janeiro (Brazil); Universidade Federal do Rio de Janeiro (UFRJ), Programa de Biologia Celular e do Desenvolvimento, Instituto de Ciencias Biomedicas, INNT/INCT/MCT, Rio de Janeiro (Brazil); Carvalho da Fonseca, Anna Carolina [Universidade Federal do Rio de Janeiro (UFRJ), Programa de Biologia Celular e do Desenvolvimento, Instituto de Ciencias Biomedicas, INNT/INCT/MCT, Rio de Janeiro (Brazil); Nunes, Sara Santana; Oliveira da Silva, Aline [Universidade do Estado do Rio de Janeiro (UERJ), Instituto de Biologia Roberto Alcantara Gomes, Departamento de Biologia Celular, Laboratorio de Biologia da Celula Endotelial e da Angiogenese (LabAngio), Rio de Janeiro (Brazil); Dubois, Luiz Gustavo Feijo; Faria, Jane; Kahn, Suzana Assad [Universidade Federal do Rio de Janeiro (UFRJ), Programa de Biologia Celular e do Desenvolvimento, Instituto de Ciencias Biomedicas, INNT/INCT/MCT, Rio de Janeiro (Brazil); Viana, Nathan Bessa [Universidade Federal do Rio de Janeiro, Laboratorio de Pincas Oticas, Coordenacao de Programas de Estudos Avancados, Instituto de Ciencias Biomedicas, Rio de Janeiro (Brazil); Universidade Federal do Rio de Janeiro, Instituto de Fisica, Rio de Janeiro (Brazil); Marcondes, Jorge [Universidade Federal do Rio de Janeiro, Hospital Universitario Clementino Fraga Filho, Servico de Neurocirurgia, Rio de Janeiro (Brazil); Legrand, Chantal [Institut Universitaire d' Hematologie, Universite Paris-Diderot, Paris 7, INSERM U553, Paris (France); Moura-Neto, Vivaldo [Universidade Federal do Rio de Janeiro (UFRJ), Programa de Biologia Celular e do Desenvolvimento, Instituto de Ciencias Biomedicas, INNT/INCT/MCT, Rio de Janeiro (Brazil); and others
2011-09-10
The extracellular matrix (ECM) contains important cues for tissue homeostasis and morphogenesis. The matricellular protein tenascin-C (TN-C) is overexpressed in remodeling tissues and cancer. In the present work, we studied the effect of different ECM-which exhibited a significant diversity in their TN-C content-in endothelial survival, proliferation and tubulogenic differentiation: autologous (endothelial) ECM devoid of TN-C, but bearing large amounts of FN; fibroblast ECM, bearing both high TN-C and FN contents; and finally, glioma-derived matrices, usually poor in FN, but very rich in TN-C. HUVECs initially adhered to the immobilized matrix produced by U373 MG glioma cells, but significantly detached and died by anoikis (50 to 80%) after 24 h, as compared with cells incubated with endothelial and fibroblast matrices. Surviving endothelial cells (20 to 50%) became up to 6-fold more proliferative and formed 74-97% less tube-like structures in vitro than cells grown on non-tumoral matrices. An antibody against the EGF-like repeats of tenascin-C (TN-C) partially rescued cells from the tubulogenic defect, indicating that this molecule is responsible for the selection of highly proliferative and tubulogenic defective endothelial cells. Interestingly, by using defined substrata, in conditions that mimic glioma and normal cell ECM composition, we observed that fibronectin (FN) modulates the TN-C-induced selection of endothelial cells. Our data show that TN-C is able to modulate endothelial branching morphogenesis in vitro and, since it is prevalent in matrices of injured and tumor tissues, also suggest a role for this protein in vascular morphogenesis, in these physiological contexts.
Tsai, Hsiao-Chi; Su, Hong-Lin; Huang, Chun-Yin; Fong, Yi-Chin; Hsu, Chin-Jung; Tang, Chih-Hsin
2014-06-15
Osteosarcoma, the most common primary malignant bone tumor, shows potent capacity for local invasion and distant metastasis. Connective tissue growth factor (CTGF/CCN2), a secreted protein, binds to integrins, modulates invasive behavior of certain human cancer cells. Effect of CTGF in metastasis of human osteosarcoma is unknown. We found overexpression of CTGF increasing matrix metalloproteinases (MMPs)-2 and MMP-3 expression as well as promoting cell migration. MicroRNA (miRNA) analysis of CTGF-overexpressed osteosarcoma versus control cells probed mechanisms of CTGF-mediated promotion of migration. Among miRNAs regulated by CTGF, miR-519d was most downregulated after CTGF treatment. Co-transfection with miR-519d mimic reversed CTGF-mediated MMPs expression and cell migration. Also, MEK and ERK inhibitors or mutants reduced CTGF-increased cell migration and miR-519d suppression. By contrast, knockdown of CTGF diminished lung metastasis in vivo. Clinical samples indicate CTGF expression as linked with clinical stage and tumor metastasis. Taken together, data show CTGF elevating MMPs expression and subsequently promoting tumor metastasis in human osteosarcoma, down-regulating miR-519d via MEK and ERK pathways, making CTGF a new molecular therapeutic target in osteosarcoma metastasis.
Tsai, Hsiao-Chi; Su, Hong-Lin; Huang, Chun-Yin; Fong, Yi-Chin; Hsu, Chin-Jung; Tang, Chih-Hsin
2014-01-01
Osteosarcoma, the most common primary malignant bone tumor, shows potent capacity for local invasion and distant metastasis. Connective tissue growth factor (CTGF/CCN2), a secreted protein, binds to integrins, modulates invasive behavior of certain human cancer cells. Effect of CTGF in metastasis of human osteosarcoma is unknown. We found overexpression of CTGF increasing matrix metalloproteinases (MMPs)-2 and MMP-3 expression as well as promoting cell migration. MicroRNA (miRNA) analysis of CTGF-overexpressed osteosarcoma versus control cells probed mechanisms of CTGF-mediated promotion of migration. Among miRNAs regulated by CTGF, miR-519d was most downregulated after CTGF treatment. Co-transfection with miR-519d mimic reversed CTGF-mediated MMPs expression and cell migration. Also, MEK and ERK inhibitors or mutants reduced CTGF-increased cell migration and miR-519d suppression. By contrast, knockdown of CTGF diminished lung metastasis in vivo. Clinical samples indicate CTGF expression as linked with clinical stage and tumor metastasis. Taken together, data show CTGF elevating MMPs expression and subsequently promoting tumor metastasis in human osteosarcoma, down-regulating miR-519d via MEK and ERK pathways, making CTGF a new molecular therapeutic target in osteosarcoma metastasis. PMID:25003330
Tagler, David; Makanji, Yogeshwar; Tu, Tao; Bernabé, Beatriz Peñalver; Lee, Raymond; Zhu, Jie; Kniazeva, Ekaterina; Hornick, Jessica E; Woodruff, Teresa K; Shea, Lonnie D
2014-07-01
The in vitro growth of ovarian follicles is an emerging technology for fertility preservation. Various strategies support the culture of secondary and multilayer follicles from various species including mice, non-human primate, and human; however, the culture of early stage (primary and primordial) follicles, which are more abundant in the ovary and survive cryopreservation, has been limited. Hydrogel-encapsulating follicle culture systems that employed feeder cells, such as mouse embryonic fibroblasts (MEFs), stimulated the growth of primary follicles (70-80 µm); yet, survival was low and smaller follicles (structure and degenerated. These morphologic changes were associated with a breakdown of the follicular basement membrane; hence, this study investigated ascorbic acid based on its role in extracellular matrix (ECM) deposition/remodeling for other applications. The selection of ascorbic acid was further supported by a microarray analysis that suggested a decrease in mRNA levels of enzymes within the ascorbate pathway between primordial, primary, and secondary follicles. The supplementation of ascorbic acid (50 µg/mL) significantly enhanced the survival of primary follicles (alginate hydrogels, which coincided with improved structural integrity. Follicles developed antral cavities and increased to diameters exceeding 250 µm. Consistent with improved structural integrity, the gene/protein expression of ECM and cell adhesion molecules was significantly changed. This research supports the notion that modifying the culture environment (medium components) can substantially enhance the survival and growth of early stage follicles. © 2013 Wiley Periodicals, Inc.
Zhang, Wei; Chen, Jialin; Backman, Ludvig J; Malm, Adam D; Danielson, Patrik
2017-03-01
The optimal functionality of the native corneal stroma is mainly dependent on the well-ordered arrangement of extracellular matrix (ECM) and the pressurized structure. In order to develop an in vitro corneal model, it is crucial to mimic the in vivo microenvironment of the cornea. In this study, the influence of surface topography and mechanical strain on keratocyte phenotype and ECM formation within a biomimetic 3D corneal model is studied. By modifying the surface topography of materials, it is found that patterned silk fibroin film with 600 grooves mm(-1) optimally supports cell alignment and ECM arrangement. Furthermore, treatment with 3% dome-shaped mechanical strain, which resembles the shape and mechanics of native cornea, significantly enhances the expression of keratocyte markers as compared to flat-shaped strain. Accordingly, a biomimetic 3D corneal model, in the form of a collagen-modified, silk fibroin-patterned construct subjected to 3% dome-shaped strain, is created. Compared to traditional 2D cultures, it supports a significantly higher expression of keratocyte and ECM markers, and in conclusion better maintains keratocyte phenotype, alignment, and fusiform cell shape. Therefore, the novel biomimetic 3D corneal model developed in this study serves as a useful in vitro 3D culture model to improve current 2D cultures for corneal studies.
Zhu, Xishan; Tai, Weiping; Shi, Wei; Song, Yuguang; Zhang, Hongmei; An, Guangyu
2012-01-01
A high level of matrix metalloproteinase-9 (MMP-9) is associated with human tumor invasion and/or metastasis. The HT1080 human fibrosarcoma cell line is highly invasive and metastatic which constitutively express MMP-9. HT1080 cells transfected with a double stranded RNA that targeted the MMP-9 mRNA and the cellular characteristics were examined before and after interference. The inhibition effects of MMP-9 interference on the tumor growth of HT1080 cells in nude mice was also tested by xenograft assay. MMP-9 extinction in HT1080 resulted in the following: (1) inhibited cell mobility; (2) increased cell adhesion, and (3) attenuated tumor cell migration. In addition, MMP-9 knockdown concomitantly resulted in decreased levels of soluble ICAM-1, leading to an adhesion defect and tumor metastasis. Moreover, in vivo assay further demonstrated MMP-9 interference affecting the tumorigenesis of HT1080 cells in mice as follows (1) inhibition of tumor growth; (2) reduced tumor volume, and (3) prolonged survival time. Our observations defined a novel critical role for MMP-9 in the progression of HT1080 fibrosarcoma by changing the inter-cellular adhesion molecular-1 from membrane-anchored state to a soluble one which provides a target for promising tumor therapy in clinics.
Directory of Open Access Journals (Sweden)
Michael J Herr
Full Text Available Tumor cell metastasis, a process which increases the morbidity and mortality of cancer patients, is highly dependent upon matrix metalloproteinase (MMP production. Small molecule inhibitors of MMPs have proven unsuccessful at reducing tumor cell invasion in vivo. Therefore, finding an alternative approach to regulate MMP is an important endeavor. Tetraspanins, a family of cell surface organizers, play a major role in cell signaling events and have been implicated in regulating metastasis in numerous cancer cell lines. We stably expressed tetraspanin CD9 in an invasive and metastatic human fibrosarcoma cell line (CD9-HT1080 to investigate its role in regulating tumor cell invasiveness. CD9-HT1080 cells displayed a highly invasive phenotype as demonstrated by matrigel invasion assays. Statistically significant increases in MMP-9 production and activity were attributed to CD9 expression and were not due to any changes in other key tetraspanin complex members or MMP regulators. Increased invasion of CD9-HT1080 cells was reversed upon silencing of MMP-9 using a MMP-9 specific siRNA. Furthermore, we determined that the second extracellular loop of CD9 was responsible for the upregulation of MMP-9 production and subsequent cell invasion. We demonstrated for the first time that tetraspanin CD9 controls HT1080 cell invasion via upregulation of an integral member of the MMP family, MMP-9. Collectively, our studies provide mounting evidence that altered expression of CD9 may be a novel approach to regulate tumor cell progression.
Herr, Michael J; Kotha, Jayaprakash; Hagedorn, Nikolaus; Smith, Blake; Jennings, Lisa K
2013-01-01
Tumor cell metastasis, a process which increases the morbidity and mortality of cancer patients, is highly dependent upon matrix metalloproteinase (MMP) production. Small molecule inhibitors of MMPs have proven unsuccessful at reducing tumor cell invasion in vivo. Therefore, finding an alternative approach to regulate MMP is an important endeavor. Tetraspanins, a family of cell surface organizers, play a major role in cell signaling events and have been implicated in regulating metastasis in numerous cancer cell lines. We stably expressed tetraspanin CD9 in an invasive and metastatic human fibrosarcoma cell line (CD9-HT1080) to investigate its role in regulating tumor cell invasiveness. CD9-HT1080 cells displayed a highly invasive phenotype as demonstrated by matrigel invasion assays. Statistically significant increases in MMP-9 production and activity were attributed to CD9 expression and were not due to any changes in other key tetraspanin complex members or MMP regulators. Increased invasion of CD9-HT1080 cells was reversed upon silencing of MMP-9 using a MMP-9 specific siRNA. Furthermore, we determined that the second extracellular loop of CD9 was responsible for the upregulation of MMP-9 production and subsequent cell invasion. We demonstrated for the first time that tetraspanin CD9 controls HT1080 cell invasion via upregulation of an integral member of the MMP family, MMP-9. Collectively, our studies provide mounting evidence that altered expression of CD9 may be a novel approach to regulate tumor cell progression.
Houston, Simon; Russell, Shannon; Hof, Rebecca; Roberts, Alanna K; Cullen, Paul; Irvine, Kyle; Smith, Derek S; Borchers, Christoph H; Tonkin, Michelle L; Boulanger, Martin J; Cameron, Caroline E
2014-02-01
The mechanisms that facilitate dissemination of the highly invasive spirochaete, Treponema pallidum, are incompletely understood. Previous studies showed the treponemal metalloprotease pallilysin (Tp0751) possesses fibrin clot degradation capability, suggesting a role in treponemal dissemination. In the current study we report characterization of the functionally linked protein Tp0750. Structural modelling predicts Tp0750 contains a von Willebrand factor type A (vWFA) domain, a protein-protein interaction domain commonly observed in extracellular matrix (ECM)-binding proteins. We report Tp0750 is a serine protease that degrades the major clot components fibrinogen and fibronectin. We also demonstrate Tp0750 cleaves a matrix metalloprotease (MMP) peptide substrate that is targeted by several MMPs, enzymes central to ECM remodelling. Through proteomic analyses we show Tp0750 binds the endothelial fibrinolytic receptor, annexin A2, in a specific and dose-dependent manner. These results suggest Tp0750 constitutes a multifunctional protein that is able to (1) degrade infection-limiting clots by both inhibiting clot formation through degradation of host coagulation cascade proteins and promoting clot dissolution by complexing with host proteins involved in the fibrinolytic cascade and (2) facilitate ECM degradation via MMP-like proteolysis of host components. We propose that through these activities Tp0750 functions in concert with pallilysin to enable T. pallidum dissemination.
Gesumaria, Lisa; Matsui, Mary S; Kluz, Thomas; Costa, Max
2015-05-01
Molecular signalling pathways delineating the induction of matrix metalloproteinases (MMPs) by ultraviolet radiation (UVR) are currently well-defined; however, the effects of UVR on epigenetic mechanisms of MMP induction are not as well understood. In this study, we examined solar-simulated UVR (ssUVR)-induced gene expression changes and alterations to histone methylation in the promoters of MMP1 and MMP3 in primary human dermal fibroblasts (HDF). Gene expression changes, including the increased expression of MMP1 and MMP3, were observed using Affymetrix GeneChip arrays and confirmed by qRT-PCR. Using ChIP-PCR, we showed for the first time that in HDF irradiated with 12 J/cm(2) ssUVR, the H3K4me3 transcriptional activating mark increased and the H3K9me2 transcriptional silencing mark decreased in abundance in promoters, correlating with the observed elevation of MMP1 and MMP3 mRNA levels following ssUVR exposure. Changes in mRNA levels due to a single exposure were transient and decreased 5 days after exposure.
Zhao, Yuan; Zhou, Feng-Li; Li, Wei-Ping; Wang, Jing; Wang, Li-Jing
2016-01-01
Whether Slit homologue 2 (Slit2) inhibits or promotes tumor cell migration remains controversial, and the role of Slit2-Roundabout 1 (Robo1) signaling in oral cancer remains to be fully elucidated. The aim of the present study was to investigate the role of Slit2-Robo1 signaling in the adhesion, invasion and migration of tongue carcinoma cells, and the mechanism by which Slit2-Robo1 signaling inhibits or promotes tumor cell migration. Tca8113 tongue carcinoma cells were treated with the monoclonal anti-human Robo1 antibody, R5, to inhibit the Slit2-Robo1 signaling pathway, with immunoglobulin (Ig)G2b treatment as a negative control. The expression levels of Slit2 and Robo1 were determined using flow cytometry. The effects of R5 on the adhesion, invasion and migration of Tca8113 tongue carcinoma cells were investigated. Gelatin zymography was used to investigate the activity of matrix metalloproteinase 2 (MMP2) and MMP9. Western blot analysis was used to evaluate the expression levels of E-cadherin in Tca8113 cells treated with 10 µg/ml of either R5 or IgG2b. Slit2 and Robo1 proteins were found to be expressed in the Tca8113 cells. R5 significantly inhibited the adhesion, invasion and migration of Tca8113 cells in vitro. R5 also inhibited the activities of MMP2 and MMP9, and increased the expression of E-cadherin in the Tca8113 cells. These results suggested that Slit2-Robo1 signaling promoted the adhesion, invasion and migration of tongue carcinoma cells by upregulating the expression levels of MMP2 and MMP9 and, downregulating the expression of E-cadherin. PMID:27431199
Li, Xia; Zhou, Qi; Tao, Ling; Yu, Chunxia
2017-09-01
Increasing evidence has demonstrated that miRNAs play a critical role in tumor development and progression. Previous studies have revealed that miR-106a is abnormally expressed in various cancers. However, its function and underlying mechanism in cervical cancer (CC) remains unknown. In this study, we confirmed that the expression of miR-106a was significantly upregulated in both CC cell lines and tissues by qRT-PCR. The increased expression of miR-106a was obviously associated with adverse prognostic features. Moreover, we demonstrated that miR-106a was a novel independent prognostic marker for predicting the 5-year survival of CC patients. The ectopic overexpression of miR‑106a promoted cell migration, invasion and invasion-related gene expression, while downregulated miR-106a reversed the effect. In addition, miR-106a regulated tissue inhibitor of metalloproteinase (TIMP)2 by directly binding to its 3'-UTR, leading to the indution of the expression of matrix metalloproteinases (MMPs). In clinical samples of CC, miR-106a was inversely correlated with TIMP2, which was downregulated in CC. Alteration of TIMP2 expression at least partially abolished the migration, invasion and MMP expression of miR-106a in CC cells. In conclusion, our data indicated that miR-106a promoted the migration, invasion and MMP expression of CC by targeting TIMP2, and may represent a novel potential therapeutic target and prognostic marker for CC.
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Jae-Hyun Park
2015-05-01
Full Text Available The stroma of breast cancer can promote the disease’s progression, but whether its composition and functions are shared among different subtypes is poorly explored. We compared stromal components of a luminal [mouse mammary tumor virus (MMTV–Neu] and a triple-negative/basal-like [C3(1–Simian virus 40 large T antigen (Tag] genetically engineered breast cancer mouse model. The types of cytokines and their expression levels were very different in the two models, as was the extent of innate immune cell infiltration; however, both models showed infiltration of innate immune cells that expressed matrix metalloproteinase 9 (MMP9, an extracellular protease linked to the progression of many types of cancer. By intercrossing with Mmp9 null mice, we found that the absence of MMP9 delayed tumor onset in the C3(1-Tag model but had no effect on tumor onset in the MMTV-Neu model. We discovered that protein levels of insulin-like growth factor binding protein-1 (IGFBP-1, an MMP9 substrate, were increased in C3(1-Tag;Mmp9−/− compared to C3(1-Tag;Mmp9+/+ tumors. In contrast, IGFBP-1 protein expression was low in MMTV-Neu tumors regardless of Mmp9 status. IGFBP-1 binds and antagonizes IGFs, preventing them from activating their receptors to promote cell proliferation and survival. Tumors from C3(1-Tag;Mmp9−/− mice had reduced IGF-1 receptor phosphorylation, consistent with slower tumor onset. Finally, gene expression analysis of human breast tumors showed that high expression of IGFBP mRNA was strongly correlated with good prognosis but not when MMP9 mRNA was also highly expressed. In conclusion, MMP9 has different effects on breast cancer progression depending on whether IGFBPs are expressed.
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Hozumi Kentaro
2016-11-01
Full Text Available Mimicking the biological function of the extracellular matrix is an approach to developing cell adhesive biomaterials. The RGD peptide, derived from fibronectin (Fn, mainly binds to integrin αvβ3 and has been widely used as a cell adhesive peptide on various biomaterials. However, cell adhesion to Fn is thought to be mediated by several integrin subtypes and syndecans. In this study, we synthesized an RGD-containing peptide (FIB1 and four integrin α4β1-binding-related motif-containing peptides (LDV, IDAPS, KLDAPT, and PRARI and constructed peptide-chitosan matrices. The FIB1-chitosan matrix promoted human dermal fibroblast (HDF attachment, and the C-terminal elongated PRARI (ePRARI-C-conjugated chitosan matrix significantly promoted HDF attachment through integrin α4β1 and syndecan binding. Next, we constructed a mixed ePRARI-C- and FIB1-chitosan matrix to develop a Fn mimetic biomaterial. The mixed ePRARI-C/FIB1-chitosan matrix promoted significantly better cell attachment and neurite outgrowth compared to those of either ePRARI-C- or FIB1-chitosan matrices. HDF adhesion to the ePRARI-C/FIB1-chitosan matrix was mediated by integrin, α4β1, α5β1, and αvβ3, similar to HDF adhesion to Fn. These data suggest that an ePRARI-C/FIB1-chitosan matrix can be used as a tool to analyze the multiple functions of Fn and can serve as a Fn-mimetic biomaterial.
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Yeh Yi-Chun
2010-08-01
Full Text Available Abstract Background This study investigated if the H. pylori dupA genotype and certain host single nucleotide polymorphisms (SNPs of matrix metalloproteinases (MMPs and their inhibitors (TIMPs, including MMP-3, MMP-7, MMP-9, TIMP-1 and TIMP-2, might correlate with ulcer risk of H. pylori-infected Taiwanese patients. Results Of the 549 H. pylori-infected patients enrolled, 470 patients (265 with gastritis, 118 with duodenal ulcer, and 87 with gastric ulcer received SNPs analysis of MMP-3-1612 6A > 5A, MMP-7-181 A > G, MMP-9exon 6 A > G, TIMP-1372 T > C and TIMP-2-418 G > C by PCR-RFLP. The 181 collected H. pylori isolates were detected for the dupA genotype by PCR. The rates of dupA-positive H. pylori infection were similar among patients with duodenal ulcer (22.8%, gastric ulcer (20.0%, and gastritis (25.5% (p > 0.05. Males had higher rates of duodenal ulcer and gastric ulcer than females (p H. pylori-infected patients, the MMP-3 6A6A genotype were more common in patients with duodenal ulcers than in those with gastritis (87.7% vs. 74.9%, p p H. pylori-infected females. Conclusions The MMP-3 promoter polymorphism, but not the dupA-status, may correlate with susceptibility to duodenal ulcer after H. pylori infection in Taiwanese females.
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Xiao-Yang Wang
Full Text Available Lung cancer is the leading cause of cancer-related deaths in the world. Achaete-scute complex homolog-1 (Ascl1 is a member of the basic helix-loop-helix (bHLH transcription factor family that has multiple functions in the normal and neoplastic lung such as the regulation of neuroendocrine differentiation, prevention of apoptosis and promotion of tumor-initiating cells. We now show that Ascl1 directly regulates matrix metalloproteinase-7 (MMP-7 and O(6-methylguanine-DNA methyltransferase (MGMT. Loss- and gain-of-function experiments in human bronchial epithelial and lung carcinoma cell lines revealed that Ascl1, MMP-7 and MGMT are able to protect cells from the tobacco-specific nitrosamine NNK-induced DNA damage and the alkylating agent cisplatin-induced apoptosis. We also examined the role of Ascl1 in NNK-induced lung tumorigenesis in vivo. Using transgenic mice which constitutively expressed human Ascl1 in airway lining cells, we found that there was a delay in lung tumorigenesis. We conclude that Ascl1 potentially enhances DNA repair through activation of MMP-7 and MGMT which may impact lung carcinogenesis and chemoresistance. The study has uncovered a novel and unexpected function of Ascl1 which will contribute to better understanding of lung carcinogenesis and the broad implications of transcription factors in tobacco-related carcinogenesis.
Stellari, Fabio Franco; Ruscitti, Francesca; Pompilio, Daniela; Ravanetti, Francesca; Tebaldi, Giulia; Macchi, Francesca; Verna, Andrea Elizabeth; Villetti, Gino; Donofrio, Gaetano
2017-01-01
Idiopathic pulmonary fibrosis is a very common interstitial lung disease derived from chronic inflammatory insults, characterized by massive scar tissue deposition that causes the progressive loss of lung function and subsequent death for respiratory failure. Bleomycin is used as the standard agent to induce experimental pulmonary fibrosis in animal models for the study of its pathogenesis. However, to visualize the establishment of lung fibrosis after treatment, the animal sacrifice is necessary. Thus, the aim of this study was to avoid this limitation by using an innovative approach based on a double bleomycin treatment protocol, along with the in vivo images analysis of bleomycin-treated mice. A reporter gene construct, containing the luciferase open reading frame under the matrix metalloproteinase-1 promoter control region, was tested on double bleomycin-treated mice to investigate, in real time, the correlation between bleomycin treatment, inflammation, tissue remodeling and fibrosis. Bioluminescence emitted by the lungs of bleomycin-treated mice, corroborated by fluorescent molecular tomography, successfully allowed real time monitoring of fibrosis establishment. The reporter gene technology experienced in this work could represent an advanced functional approach for real time non-invasive assessment of disease evolution during therapy, in a reliable and translational living animal model. PMID:28298912
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Shukla Shirish
2010-07-01
Full Text Available Abstract Background Matrix metalloproteinases (MMPs are enzymes that degrade all the components of extra cellular matrix and collagen. Various types of MMPs are known to be expressed and activated in patients with oral submucous fibrosis (OSMF as well as head and neck squamous cell carcinoma (HNSCC. The purpose of this study was to asses the association of the single nucleotide polymorphism (SNP adenosine insertion/deletion polymorphism (-1171 5A->6A in the MMP-3 promoter region in these lesions. Methods MMP-3 SNP was genotyped by polymerase chain reaction-restriction fragment polymorphism (PCR-RFLP analysis in a case control study consisting of 362 participants; 101 cases of OSMF, 135 of HNSCC and 126 controls, compared for age, sex and habits. ROC distribution was plotted to assess the contributions of genetic variation in MMP-3 genotypes with relation to age. Results Analysis of MMP 3 (-1171 5A->6A polymorphism revealed the frequency of 5A allele in OSMF, HNSCC and controls to be 0.15, 0.13 and 0.07, respectively. A significant difference was found in 5A genotype frequency between OSMF (5A genotype frequency = 0.15, p = 0.01, OR = 2.26, 95% CI = 1.22-4.20 and in controls (5A genotype frequency 0.07 as well as HNSCC (5A genotype frequency 0.13, p = 0.03,95%CI = 1.06-3.51 and controls (5A genotype frequency = 0.07 In this study, 5A genotype had greater than two fold risk for developing OSMF (OR = 2.26 and nearly the same in case of HNSCC (OR = 1.94 as compared to controls. In patients with OSMF as well as HNSCC, the ROC analysis between the MMP-3 genotype and age, 6A/6A allele was found to be significant in patients both over and under 45 years of age; while the 5A/5A carrier alleles showed an association only in patients less than 45 years of age. Conclusions This study concluded that the expression of MMP-3 genotype associated with the 5A alleles, it may have an important role in the susceptibility of the patients to develop OSMF and HNSCC.
Institute of Scientific and Technical Information of China (English)
雷萍; 杨家燕; 王惠森
2015-01-01
This paper summarizes the current situation of reading promotion team building in university library,analyzes the advantages of application of matrix management model in team building of reading promotion in university library,and points out that the application of matrix management for strengthening reading promotion team building in university library should pay attention to the good team leader select off, clear team management processes and the members of the mission requirements,pay attention to adjust the balance of the workload and to promote cooperation,but also optimize performance evaluation,establish the reading promotion activities evaluation and reward and punishment system.%矩阵管理是指为完成某项特定工作任务而形成的工作小组的管理模式。应用矩阵管理模式加强高校图书馆阅读推广团队建设，应注意把好团队负责人选择关，明确团队管理流程和成员的任务要求，注重各业务点的工作量均衡，促进各业务环节的配合，同时优化绩效评估方式，建立阅读推广活动评价和奖惩机制。
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Xin Wang
Full Text Available OBJECTIVES: To investigate whether a combination of demineralized bone matrix (DBM and bone marrow mesenchymal stem cells (BMSCs infected with adenovirus-mediated- bone morphogenetic protein (Ad-BMP-2 and transforming growth factor-β3 (Ad-TGF-β3 promotes the repair of the full-thickness cartilage lesions in pig model. METHODS: BMSCs isolated from pig were cultured and infected with Ad-BMP-2(B group, Ad-TGF-β3 (T group, Ad-BMP-2 + Ad-TGF-β3(BT group, cells infected with empty Ad served as a negative group(N group, the expression of the BMP-2 and TGF-β3 were confirmed by immunofluorescence, PCR, and ELISA, the expression of SOX-9, type II collagen(COL-2A, aggrecan (ACAN in each group were evaluated by real-time PCR at 1w, 2w, 3w, respectively. The chondrogenic differentiation of BMSCs was evaluated by type II collagen at 21d with immunohistochemical staining. The third-passage BMSCs infected with Ad-BMP-2 and Ad-TGF-β3 were suspended and cultured with DBM for 6 days to construct a new type of tissue engineering scaffold to repair full-thickness cartilage lesions in the femur condyles of pig knee, the regenerated tissue was evaluated at 1,2 and 3 months after surgery by gross appearance, H&E, safranin O staining and O'driscoll score. RESULTS: Ad-BMP-2 and Ad-TGF-β3 (BT group infected cells acquired strong type II collagen staining compared with Ad-BMP-2 (B group and Ad-TGF-β3 (T group along. The Ad-BMP-2 and Ad-TGF-β3 infected BMSCs adhered and propagated well in DBM and the new type of tissue engineering scaffold produced hyaline cartilage morphology containing a stronger type II collagen and safranin O staining, the O'driscoll score was higher than other groups. CONCLUSIONS: The DBM compound with Ad-BMP-2 and Ad-TGF-β3 infected BMSCs scaffold has a good biocompatibility and could well induce cartilage regeneration to repair the defects of joint cartilage. This technology may be efficiently employed for cartilage lesions repair in vivo.
Bahrehmand, F; Vaisi-Raygani, A; Kiani, A; Rahimi, Z; Tavilani, H; Navabi, S J; Shakiba, E; Hassanzadeh, N; Pourmotabbed, T
2012-05-01
Matrix metalloproteinase-2 (MMP-2) is a zinc dependent endonuclease that degrades type IV collagen, the major structural component of basement membranes. MMP-2 functional promoter polymorphism G1575A affects circulating level of MMP-2 and may be considered an important genetic determinant of cardiovascular disease (CVD) in systemic lupus erythematosus (SLE) patients. In this study, association between MMP-2 1575A allele with serum MMP-2, neopterin and lipid-lipoprotein levels and with SLE and developing CVD was investigated. The present case-control study consisted of 109 SLE patients with and without CVD (mean age, 35.6 years) and 101 gender- and age-matched, unrelated, healthy controls (mean age, 37.1 years) from the population in the west of Iran. MMP-2 1575G/A polymorphism was detected by polymerase chain reaction (restriction fragment length polymorphism) PCR-RFLP, serum MMP-2, neopterin and lipid levels were determined by enzyme-linked immunosorbent assay (ELISA), high-performance liquid chromatography (HPLC) and enzyme assay, respectively. The presence of MMP-2 G1575A allele was found to be associated with SLE and developed CVD (OR = 1.78, p = 0.029 and OR = 3.43, p = 0.025, respectively). The SLE patients with MMP-2 A (G/A + A/A) allele had higher MMP-2 activity (301 ± 166 vs. 194 ± 35.5, p = 0.002), neopterin (29.4 ± 39.4 vs. 7.3 ± 4.6, p = 0.005), LDL-C (120 ± 25.7 vs. 87 ± 39.3, p = 0.045) and lower HDL-C (39.6 ± 11 vs. 45.9 ± 11.8, p = 0.031) levels than the control subjects. There was a significantly positive correlation between MMP-2 level with neopterin, total cholesterol and TG levels and negative correlation with HDL-C level in SLE patients with CVD. MMP-2 G1575A allele may be a risk factor for SLE. The carriers of this allele have high levels of MMP-2, neopterin, total cholesterol and TG and lower levels of HDL, thus, they are more likely to develop heart disease.
Franklin, Joel N
2003-01-01
Mathematically rigorous introduction covers vector and matrix norms, the condition-number of a matrix, positive and irreducible matrices, much more. Only elementary algebra and calculus required. Includes problem-solving exercises. 1968 edition.
Tani, Akio; Sahin, Nurettin; Fujitani, Yoshiko; Kato, Akiko; Sato, Kazuhiro; Kimbara, Kazuhide
2015-01-01
Methylobacterium species frequently inhabit plant surfaces and are able to utilize the methanol emitted from plants as carbon and energy sources. As some of the Methylobacterium species are known to promote plant growth, significant attention has been paid to the mechanism of growth promotion and the specificity of plant-microbe interactions. By screening our Methylobacterium isolate collection for the high growth promotion effect in vitro, we selected some candidates for field and pot growth tests for rice and barley, respectively. We found that inoculation resulted in better ripening of rice seeds, and increased the size of barley grains but not the total yield. In addition, using whole-cell matrix-assister laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF/MS) analysis, we identified and classified Methylobacterium isolates from Methylobacterium-inoculated rice plants. The inoculated species could not be recovered from the rice plants, and in some cases, the Methylobacterium community structure was affected by the inoculation, but not with predomination of the inoculated species. The isolates from non-inoculated barley of various cultivars grown in the same field fell into just two species. These results suggest that there is a strong selection pressure at the species level of Methylobacterium residing on a given plant species, and that selection of appropriate species that can persist on the plant is important to achieve growth promotion.
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Akio Tani
Full Text Available Methylobacterium species frequently inhabit plant surfaces and are able to utilize the methanol emitted from plants as carbon and energy sources. As some of the Methylobacterium species are known to promote plant growth, significant attention has been paid to the mechanism of growth promotion and the specificity of plant-microbe interactions. By screening our Methylobacterium isolate collection for the high growth promotion effect in vitro, we selected some candidates for field and pot growth tests for rice and barley, respectively. We found that inoculation resulted in better ripening of rice seeds, and increased the size of barley grains but not the total yield. In addition, using whole-cell matrix-assister laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF/MS analysis, we identified and classified Methylobacterium isolates from Methylobacterium-inoculated rice plants. The inoculated species could not be recovered from the rice plants, and in some cases, the Methylobacterium community structure was affected by the inoculation, but not with predomination of the inoculated species. The isolates from non-inoculated barley of various cultivars grown in the same field fell into just two species. These results suggest that there is a strong selection pressure at the species level of Methylobacterium residing on a given plant species, and that selection of appropriate species that can persist on the plant is important to achieve growth promotion.
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Fanglong Song
2017-02-01
Full Text Available Background/Aims: This study investigated the effect of mechanical stress on tendon-bone healing in a rabbit anterior cruciate ligament (ACL reconstruction model as well as cell proliferation and matrix formation in co-culture of bone-marrow mesenchymal stem cells (BMSCs and tendon cells (TCs. Methods: The effect of continuous passive motion (CPM therapy on tendon-bone healing in a rabbit ACL reconstruction model was evaluated by histological analysis, biomechanical testing and gene expressions at the tendon-bone interface. Furthermore, the effect of mechanical stretch on cell proliferation and matrix synthesis in BMSC/TC co-culture was also examined. Results: Postoperative CPM therapy significantly enhanced tendon-bone healing, as evidenced by increased amount of fibrocartilage, elevated ultimate load to failure levels, and up-regulated gene expressions of Collagen I, alkaline phosphatase, osteopontin, Tenascin C and tenomodulin at the tendon-bone junction. In addition, BMSC/TC co-culture treated with mechanical stretch showed a higher rate of cell proliferation and enhanced expressions of Collagen I, Collagen III, alkaline phosphatase, osteopontin, Tenascin C and tenomodulin than that of controls. Conclusion: These results demonstrated that proliferation and differentiation of local precursor cells could be enhanced by mechanical stimulation, which results in enhanced regenerative potential of BMSCs and TCs in tendon-bone healing.
Matrix Factorization and Matrix Concentration
Mackey, Lester
2012-01-01
Motivated by the constrained factorization problems of sparse principal components analysis (PCA) for gene expression modeling, low-rank matrix completion for recommender systems, and robust matrix factorization for video surveillance, this dissertation explores the modeling, methodology, and theory of matrix factorization.We begin by exposing the theoretical and empirical shortcomings of standard deflation techniques for sparse PCA and developing alternative methodology more suitable for def...
Bodewig, E
1959-01-01
Matrix Calculus, Second Revised and Enlarged Edition focuses on systematic calculation with the building blocks of a matrix and rows and columns, shunning the use of individual elements. The publication first offers information on vectors, matrices, further applications, measures of the magnitude of a matrix, and forms. The text then examines eigenvalues and exact solutions, including the characteristic equation, eigenrows, extremum properties of the eigenvalues, bounds for the eigenvalues, elementary divisors, and bounds for the determinant. The text ponders on approximate solutions, as well
Hanker, Ariella B; Estrada, Mónica Valeria; Bianchini, Giampaolo; Moore, Preston D; Zhao, Junfei; Cheng, Feixiong; Koch, James P; Gianni, Luca; Tyson, Darren R; Sánchez, Violeta; Rexer, Brent N; Sanders, Melinda E; Zhao, Zhongming; Stricker, Thomas P; Arteaga, Carlos L
2017-06-15
PIK3CA mutations are associated with resistance to HER2-targeted therapies. We previously showed that HER2(+)/PIK3CA(H1047R) transgenic mammary tumors are resistant to the HER2 antibodies trastuzumab and pertuzumab but respond to PI3K inhibitor buparlisib (TPB). In this study, we identified mechanisms of resistance to combined inhibition of HER2 and PI3K. TPB-resistant tumors were generated by treating HER2(+)/PIK3CA(H1047R) tumor-bearing mice long term with the drug combination. RNA sequencing of TPB-resistant tumors revealed that extracellular matrix and cell adhesion genes, including collagen II (Col2a1), were markedly upregulated, accompanied by activation of integrin β1/Src. Cells derived from drug-resistant tumors were sensitive to TBP when grown in vitro, but exhibited resistance when plated on collagen or when reintroduced into mice. Drug resistance was partially reversed by the collagen synthesis inhibitor ethyl-3,4-dihydroxybenzoate. Inhibition of integrin β1/Src blocked collagen-induced resistance to TPB and inhibited growth of drug-resistant tumors. High collagen II expression was associated with significantly lower clinical response to neoadjuvant anti-HER2 therapy in HER2(+) breast cancer patients. Overall, these data suggest that upregulation of collagen/integrin/Src signaling contributes to resistance to combinatorial HER2 and PI3K inhibition. Cancer Res; 77(12); 3280-92. ©2017 AACR. ©2017 American Association for Cancer Research.
Dickens, Stijn; Vermeulen, Pieter; Hendrickx, Benoit; Van den Berge, Stefaan; Vranckx, Jan J
2008-01-01
The intricate wound repair process involves the interplay of numerous cells and proteins. Using a porcine full-thickness wound (FTW) healing model, we hypothesized that the ex vivo gene transfer of vascular endothelial growth factor (VEGF)-transfected basal keratinocyte (KC) cell suspensions may generate cross-talk and induce matrix formation, angiogenesis, and accelerated healing. Moreover, to regulate overexpression of isoform 165 of VEGF and its effect on healing, we introduced a tetracycline (TC)-inducible gene switch in the expression plasmid. Autologous basal KCs were cultivated from the porcine donor and transfected using cationic liposomes. A dose-response curve was established to determine optimal activation of the gene switch by TC. In vivo, FTWs were treated with VEGF-transfected KCs and controls. Wound fluids were collected daily and examined using enzyme-linked immunosorbent assay. Biopsies were evaluated using hematoxylin and eosin and immunostaining for fibronectin, CD144, and lectin BS-1. In vitro, highest regulable VEGF165-expression was obtained with 1 microg/mL of TCs. In vivo, after induction of the gene switch by adding 1 microg/mL of TCs to the FTW, we obtained upregulated VEGF165 levels and enhanced fibronectin deposition and found more endothelial cell tubular formations and higher rates of reepithelialization than in controls. This ex vivo gene transfer model may serve as a platform for vascular induction in full-thickness tissue repair.
Yoo, Byong Hoon; Zagryazhskaya, Anna; Li, Yongling; Koomson, Ananda; Khan, Iman Aftab; Sasazuki, Takehiko; Shirasawa, Senji; Rosen, Kirill V
2015-01-01
Detachment of nonmalignant intestinal epithelial cells from the extracellular matrix (ECM) triggers their growth arrest and, ultimately, apoptosis. In contrast, colorectal cancer cells can grow without attachment to the ECM. This ability is critical for their malignant potential. We found previously that detachment-induced growth arrest of nonmalignant intestinal epithelial cells is driven by their detachment-triggered autophagy, and that RAS, a major oncogene, promotes growth of detached cells by blocking such autophagy. In an effort to identify the mechanisms of detachment-induced autophagy and growth arrest of nonmalignant cells we found here that detachment of these cells causes upregulation of ATG3 and that ATG3 upregulation contributes to autophagy and growth arrest of detached cells. We also observed that when ATG3 expression is artificially increased in the attached cells, ATG3 promotes neither autophagy nor growth arrest but triggers their apoptosis. ATG3 upregulation likely promotes autophagy of the detached but not that of the attached cells because detachment-dependent autophagy requires other detachment-induced events, such as the upregulation of ATG7. We further observed that those few adherent cells that do not die by apoptosis induced by ATG3 become resistant to apoptosis caused by cell detachment, a property that is critical for the ability of normal epithelial cells to become malignant. We conclude that cell-ECM adhesion can switch ATG3 functions: when upregulated in detached cells in the context of other autophagy-promoting events, ATG3 contributes to autophagy. However, when overexpressed in the adherent cells, in the circumstances not favoring autophagy, ATG3 triggers apoptosis.
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Conor C. Lynch
2010-01-01
Full Text Available Perturbations in cell-cell contact machinery occur frequently in epithelial cancers and result in increased cancer cell migration and invasion. Previously, we demonstrated that MMP-7, a protease implicated in mammary and intestinal tumor growth, can process the adherens junction component E-cadherin. This observation leads us to test whether MMP-7 processing of E-cadherin could directly impact cell proliferation in nontransformed epithelial cell lines (MDCK and C57MG. Our goal was to investigate the possibility that MMP-7 produced by cancer cells may have effects on adjacent normal epithelium. Here, we show that MMP-7 processing of E-cadherin mediates, (1 loss of cell-cell contact, (2 increased cell migration, (3 a loss of epithelial cell polarization and (4 increased cell proliferation via RhoA activation. These data demonstrate that MMP-7 promotes epithelial cell proliferation via the processing of E-cadherin and provide insights into the molecular mechanisms that govern epithelial cell growth.
Bhatia, Rajendra
2013-01-01
This book is an outcome of the Indo-French Workshop on Matrix Information Geometries (MIG): Applications in Sensor and Cognitive Systems Engineering, which was held in Ecole Polytechnique and Thales Research and Technology Center, Palaiseau, France, in February 23-25, 2011. The workshop was generously funded by the Indo-French Centre for the Promotion of Advanced Research (IFCPAR). During the event, 22 renowned invited french or indian speakers gave lectures on their areas of expertise within the field of matrix analysis or processing. From these talks, a total of 17 original contribution or state-of-the-art chapters have been assembled in this volume. All articles were thoroughly peer-reviewed and improved, according to the suggestions of the international referees. The 17 contributions presented are organized in three parts: (1) State-of-the-art surveys & original matrix theory work, (2) Advanced matrix theory for radar processing, and (3) Matrix-based signal processing applications.
Craps, Ben; Nguyen, Kévin
2016-01-01
Matrix quantum mechanics offers an attractive environment for discussing gravitational holography, in which both sides of the holographic duality are well-defined. Similarly to higher-dimensional implementations of holography, collapsing shell solutions in the gravitational bulk correspond in this setting to thermalization processes in the dual quantum mechanical theory. We construct an explicit, fully nonlinear supergravity solution describing a generic collapsing dilaton shell, specify the holographic renormalization prescriptions necessary for computing the relevant boundary observables, and apply them to evaluating thermalizing two-point correlation functions in the dual matrix theory.
Shantha Kumara, H M C; Gaita, David J; Miyagaki, Hiromichi; Yan, Xiaohong; Herath, Sonali A C; Cekic, Vesna; Whelan, Richard L
2014-12-01
MMP-3, a member of the matrix metalloproteinase (MMP) family, is involved in the breakdown of the extracellular matrix in tissue remodeling and may also play a role in cancer progression and metastasis. Minimally invasive colorectal resection (MICR) may increase plasma MMP-3 levels directly via surgical trauma or indirectly due to surgery-associated elevations in TNF-α and IL1 which are regulators of MMP-3. This study's purpose was to evaluate plasma MMP-3 levels during the first month after MICR for colorectal cancer. Patients enrolled in an IRB approved data/plasma bank who underwent elective MICR for CRC. Blood plasma samples had been collected preoperatively, on postoperative day (POD) 1, 3 and at varying postoperative time points and were stored at -80 °C. The late samples (POD 7-41) were bundled into 7 day time blocks and considered as single time points. MMP-3 levels were analyzed in duplicate via ELISA and the results reported as mean ± SD. The paired t test was used for analysis (significance, p MICR met the inclusion criteria. The mean PreOp MMP-3 level was 14.9 ± 7.8 ng/ml (n = 73). Significantly elevated mean plasma levels were noted on POD 1 (21.4 ± 14.7 ng/ml, n = 73, p MICR for CRC. The early postoperative increase in MMP-3 levels may be due to the surgery-related acute inflammatory response; the elevation noted during weeks 2-3 may be related to wound healing. Increased MMP-3 levels may promote metastases or the growth of residual cancer.
Zhan, Xingzhi
2002-01-01
The main purpose of this monograph is to report on recent developments in the field of matrix inequalities, with emphasis on useful techniques and ingenious ideas. Among other results this book contains the affirmative solutions of eight conjectures. Many theorems unify or sharpen previous inequalities. The author's aim is to streamline the ideas in the literature. The book can be read by research workers, graduate students and advanced undergraduates.
Bhatia, Rajendra
1997-01-01
A good part of matrix theory is functional analytic in spirit. This statement can be turned around. There are many problems in operator theory, where most of the complexities and subtleties are present in the finite-dimensional case. My purpose in writing this book is to present a systematic treatment of methods that are useful in the study of such problems. This book is intended for use as a text for upper division and gradu ate courses. Courses based on parts of the material have been given by me at the Indian Statistical Institute and at the University of Toronto (in collaboration with Chandler Davis). The book should also be useful as a reference for research workers in linear algebra, operator theory, mathe matical physics and numerical analysis. A possible subtitle of this book could be Matrix Inequalities. A reader who works through the book should expect to become proficient in the art of deriving such inequalities. Other authors have compared this art to that of cutting diamonds. One first has to...
Belitsky, A V
2016-01-01
The Operator Product Expansion for null polygonal Wilson loop in planar maximally supersymmetric Yang-Mills theory runs systematically in terms of multiparticle pentagon transitions which encode the physics of excitations propagating on the color flux tube ending on the sides of the four-dimensional contour. Their dynamics was unravelled in the past several years and culminated in a complete description of pentagons as an exact function of the 't Hooft coupling. In this paper we provide a solution for the last building block in this program, the SU(4) matrix structure arising from internal symmetry indices of scalars and fermions. This is achieved by a recursive solution of the Mirror and Watson equations obeyed by the so-called singlet pentagons and fixing the form of the twisted component in their tensor decomposition. The non-singlet, or charged, pentagons are deduced from these by a limiting procedure.
DEFF Research Database (Denmark)
Coussens, P.M.; Pudrith, C.B.; Skovgaard, Kerstin
2005-01-01
remodeling deficiencies through higher expression of tissue inhibitor of matrix metalloproteinase (TIMP) 1 and TIMP2 RNA and lower expression of matrix metalloproteinase (MMP) 14 RNA than similar cells from healthy controls, and that cells within the PBMC population of M. paratuberculosis-infected cows...
Kargın, Levent; Kurt, Veli
2015-01-01
In this study, obtaining the matrix analog of the Euler's reflection formula for the classical gamma function we expand the domain of the gamma matrix function and give a infinite product expansion of sinπxP. Furthermore we define Riemann zeta matrix function and evaluate some other matrix integrals. We prove a functional equation for Riemann zeta matrix function.
DEFF Research Database (Denmark)
Petersen, Kaare Brandt; Pedersen, Michael Syskind
Matrix identities, relations and approximations. A desktop reference for quick overview of mathematics of matrices.......Matrix identities, relations and approximations. A desktop reference for quick overview of mathematics of matrices....
Matrix with Prescribed Eigenvectors
Ahmad, Faiz
2011-01-01
It is a routine matter for undergraduates to find eigenvalues and eigenvectors of a given matrix. But the converse problem of finding a matrix with prescribed eigenvalues and eigenvectors is rarely discussed in elementary texts on linear algebra. This problem is related to the "spectral" decomposition of a matrix and has important technical…
Saladino, Silvia; Salamone, Monica; Ghersi, Giulio
2017-09-01
Tumor angiogenesis is a multiphasic process, having the extracellular matrix remodeling as critical step. Different classes of proteolytic enzymes in matrix digestion/remodeling are involved. The role of lytic enzymes and their activation mode have not been completely elucidated. Herein, the crosstalk between endothelia and tumor cells, by realization of bi- and three-dimensional endothelial and breast cancer cells co-cultures, were studied in vitro. Particularly, the effects of two tumor conditioned media (TCM) were assessed about endothelial proliferation, migration, and invasiveness. An increase in expression of pro-MMP9 was detected when endothelial cells were cultured in the presence of both TCM; such as an up-regulation of MMP1 and MMP14 and a down-regulation of MMP7. Moreover the increased MMP2 gene expression from one of them and the stimulation MMP3 synthesis from the other one were observed; an increases of β3-integrin, VEGFA, and DPP4 molecules were detected when endothelia cells are cultured with both TCM. The selection/characterization of elements present in conditioned media from breast cancer cells differently affect endothelial cells, make them potential effectors useful in breast cancer treatment. © 2017 International Federation for Cell Biology.
Institute of Scientific and Technical Information of China (English)
胡景超; 束蓉
2009-01-01
釉基质蛋白(enamel matrix proteins,EMPs)参与诱导再生形成的牙周组织在形态结构和生物学功能上接近于正常组织.而目前对EMPs促进再生的相关机制尚不完全清楚.该文在探讨EMPs组成成分、功能的基础上,结合EMPs对牙周组织再生相关细胞的作用,就近年来EMPs促进牙周再生作用机制的研究进展作一综述.
Parallelism in matrix computations
Gallopoulos, Efstratios; Sameh, Ahmed H
2016-01-01
This book is primarily intended as a research monograph that could also be used in graduate courses for the design of parallel algorithms in matrix computations. It assumes general but not extensive knowledge of numerical linear algebra, parallel architectures, and parallel programming paradigms. The book consists of four parts: (I) Basics; (II) Dense and Special Matrix Computations; (III) Sparse Matrix Computations; and (IV) Matrix functions and characteristics. Part I deals with parallel programming paradigms and fundamental kernels, including reordering schemes for sparse matrices. Part II is devoted to dense matrix computations such as parallel algorithms for solving linear systems, linear least squares, the symmetric algebraic eigenvalue problem, and the singular-value decomposition. It also deals with the development of parallel algorithms for special linear systems such as banded ,Vandermonde ,Toeplitz ,and block Toeplitz systems. Part III addresses sparse matrix computations: (a) the development of pa...
Institute of Scientific and Technical Information of China (English)
无
2003-01-01
Matrix-bound phosphine was determined in the Jiaozhou Bay coastal sediment, in prawn-pond bottom soil, in the eutrophic lake Wulongtan, in the sewage sludge and in paddy soil as well. Results showed that matrix-bound phosphine levels in freshwater and coastal sediment, as well as in sewage sludge, are significantly higher than that in paddy soil. The correlation between matrix bound phosphine concentrations and organic phosphorus contents in sediment samples is discussed.
DEFF Research Database (Denmark)
Lenhard, Boris; Sandelin, Albin Gustav; Carninci, Piero
2012-01-01
Promoters are crucial for gene regulation. They vary greatly in terms of associated regulatory elements, sequence motifs, the choice of transcription start sites and other features. Several technologies that harness next-generation sequencing have enabled recent advances in identifying promoters...... and their features, helping researchers who are investigating functional categories of promoters and their modes of regulation. Additional features of promoters that are being characterized include types of histone modifications, nucleosome positioning, RNA polymerase pausing and novel small RNAs. In this Review, we...... discuss recent findings relating to metazoan promoters and how these findings are leading to a revised picture of what a gene promoter is and how it works....
DEFF Research Database (Denmark)
Hansen, Kristoffer Arnsfelt; Ibsen-Jensen, Rasmus; Podolskii, Vladimir V.;
2013-01-01
For matrix games we study how small nonzero probability must be used in optimal strategies. We show that for image win–lose–draw games (i.e. image matrix games) nonzero probabilities smaller than image are never needed. We also construct an explicit image win–lose game such that the unique optimal...
DEFF Research Database (Denmark)
Hansen, Kristoffer Arnsfelt; Ibsen-Jensen, Rasmus; Podolskii, Vladimir V.
2013-01-01
For matrix games we study how small nonzero probability must be used in optimal strategies. We show that for image win–lose–draw games (i.e. image matrix games) nonzero probabilities smaller than image are never needed. We also construct an explicit image win–lose game such that the unique optimal...
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.
Improved Matrix Uncertainty Selector
Rosenbaum, Mathieu
2011-01-01
We consider the regression model with observation error in the design: y=X\\theta* + e, Z=X+N. Here the random vector y in R^n and the random n*p matrix Z are observed, the n*p matrix X is unknown, N is an n*p random noise matrix, e in R^n is a random noise vector, and \\theta* is a vector of unknown parameters to be estimated. We consider the setting where the dimension p can be much larger than the sample size n and \\theta* is sparse. Because of the presence of the noise matrix N, the commonly used Lasso and Dantzig selector are unstable. An alternative procedure called the Matrix Uncertainty (MU) selector has been proposed in Rosenbaum and Tsybakov (2010) in order to account for the noise. The properties of the MU selector have been studied in Rosenbaum and Tsybakov (2010) for sparse \\theta* under the assumption that the noise matrix N is deterministic and its values are small. In this paper, we propose a modification of the MU selector when N is a random matrix with zero-mean entries having the variances th...
Eves, Howard
1980-01-01
The usefulness of matrix theory as a tool in disciplines ranging from quantum mechanics to psychometrics is widely recognized, and courses in matrix theory are increasingly a standard part of the undergraduate curriculum.This outstanding text offers an unusual introduction to matrix theory at the undergraduate level. Unlike most texts dealing with the topic, which tend to remain on an abstract level, Dr. Eves' book employs a concrete elementary approach, avoiding abstraction until the final chapter. This practical method renders the text especially accessible to students of physics, engineeri
Rheocasting Al matrix composites
Energy Technology Data Exchange (ETDEWEB)
Girot, F.A.; Albingre, L.; Quenisset, J.M.; Naslain, R.
1987-11-01
A development status account is given for the rheocasting method of Al-alloy matrix/SiC-whisker composites, which involves the incorporation and homogeneous distribution of 8-15 vol pct of whiskers through the stirring of the semisolid matrix melt while retaining sufficient fluidity for casting. Both 1-, 3-, and 6-mm fibers of Nicalon SiC and and SiC whisker reinforcements have been experimentally investigated, with attention to the characterization of the resulting microstructures and the effects of fiber-matrix interactions. A thin silica layer is found at the whisker surface. 7 references.
Mueller matrix differential decomposition.
Ortega-Quijano, Noé; Arce-Diego, José Luis
2011-05-15
We present a Mueller matrix decomposition based on the differential formulation of the Mueller calculus. The differential Mueller matrix is obtained from the macroscopic matrix through an eigenanalysis. It is subsequently resolved into the complete set of 16 differential matrices that correspond to the basic types of optical behavior for depolarizing anisotropic media. The method is successfully applied to the polarimetric analysis of several samples. The differential parameters enable one to perform an exhaustive characterization of anisotropy and depolarization. This decomposition is particularly appropriate for studying media in which several polarization effects take place simultaneously. © 2011 Optical Society of America
动态压力促进骨基质支架中微血管形成的实验研究%Study of dynamic pressure to promote the angiogenesis of bone matrix
Institute of Scientific and Technical Information of China (English)
杨军; 周振东; 李建军; 张钦明
2011-01-01
Objective To observe the effects of dynamic pressure for the ability of endothelial progenitor cells (EPCs) to form blood vessels, when EPCs seeded into DBM with load. Methods Use the Ficoll density gradient centrifuge combined with difference-speed adherence screening method to separate MNCs from rat bone marrow. Identify the induced EPCs by means of immunohistochemistry and immunofluorescence. Through the organization of fixed, defatted, decalcified and other steps use of spine vertebral body,demineralized bone matrix (DBM) samples of pig were prepared in vitro. Divided scaffolds into two groups A and groups B. Induced EPCs were seeded into DBM. The cell-seeded scaffolds of groups A were dynamically loaded in compression using a sine wave at 1 Hz, 5% strain in the media-filled chamber for 4 h on days 5 of culture. and cell-seeded scaffolds of groups B were cultured directly without any load. Both of two groups were cultured two weeks. Then the ability of EPCs to form blood vessels was observed. Primer desig;Extract total RNA from cells with Trlzol; Reverse transcription reaction; PCR. Results Two groups of cells in HE staining and fluorescent staining showed the formation of vascular bundles. There were formation of blood vessels. It was obvious that the formation in group A was more than that in group B. Test the mRNA expression of vWF and Flk-1 during the EPCs differentiationby RT-PCR. Group A was significantly stronger than that of group B. Conclusion When DBM combines together with EPC, it has become organization engineering bone, then with press on it, the bone graft has been vascularized, so it has clinical application on the direction of repair bone defect.%目的 将血管内皮祖细胞(endothelial progenitor cells,EPCs)种植于体外制备的猪脱钙骨基质支架中,予适当压力干预,观察动态压力对EPCs形成血管能力的影响.方法 采用密度梯度离心法结合差速贴壁筛选法分离出骨髓单个核细胞,用条件培养液
The "Pesticide-exposure Matrix" was developed to help epidemiologists and other researchers identify the active ingredients to which people were likely exposed when their homes and gardens were treated for pests in past years.
Koehler, Wolfgang
2011-01-01
A new classical theory of gravitation within the framework of general relativity is presented. It is based on a matrix formulation of four-dimensional Riemann-spaces and uses no artificial fields or adjustable parameters. The geometrical stress-energy tensor is derived from a matrix-trace Lagrangian, which is not equivalent to the curvature scalar R. To enable a direct comparison with the Einstein-theory a tetrad formalism is utilized, which shows similarities to teleparallel gravitation theories, but uses complex tetrads. Matrix theory might solve a 27-year-old, fundamental problem of those theories (sec. 4.1). For the standard test cases (PPN scheme, Schwarzschild-solution) no differences to the Einstein-theory are found. However, the matrix theory exhibits novel, interesting vacuum solutions.
DEFF Research Database (Denmark)
Schneider, Jesper Wiborg; Borlund, Pia
2007-01-01
The present two-part article introduces matrix comparison as a formal means for evaluation purposes in informetric studies such as cocitation analysis. In the first part, the motivation behind introducing matrix comparison to informetric studies, as well as two important issues influencing...... such comparisons, matrix generation, and the composition of proximity measures, are introduced and discussed. In this second part, the authors introduce and thoroughly demonstrate two related matrix comparison techniques the Mantel test and Procrustes analysis, respectively. These techniques can compare...... important. Alternatively, or as a supplement, Procrustes analysis compares the actual ordination results without investigating the underlying proximity measures, by matching two configurations of the same objects in a multidimensional space. An advantage of the Procrustes analysis though, is the graphical...
The Matrix Organization Revisited
DEFF Research Database (Denmark)
Gattiker, Urs E.; Ulhøi, John Parm
1999-01-01
This paper gives a short overview of matrix structure and technology management. It outlines some of the characteristics and also points out that many organizations may actualy be hybrids (i.e. mix several ways of organizing to allocate resorces effectively).......This paper gives a short overview of matrix structure and technology management. It outlines some of the characteristics and also points out that many organizations may actualy be hybrids (i.e. mix several ways of organizing to allocate resorces effectively)....
Optical Coherency Matrix Tomography
2015-10-19
optics has been studied theoretically11, but has not been demonstrated experimentally heretofore. Even in the simplest case of two binary DoFs6 (e.g...coherency matrix G spanning these DoFs. This optical coherency matrix has not been measured in its entirety to date—even in the simplest case of two...dense coding, etc. CREOL, The College of Optics & Photonics, University of Central Florida, Orlando , Florida 32816, USA. Correspondence and requests
Tenreiro Machado, J. A.
2015-08-01
This paper addresses the matrix representation of dynamical systems in the perspective of fractional calculus. Fractional elements and fractional systems are interpreted under the light of the classical Cole-Cole, Davidson-Cole, and Havriliak-Negami heuristic models. Numerical simulations for an electrical circuit enlighten the results for matrix based models and high fractional orders. The conclusions clarify the distinction between fractional elements and fractional systems.
Czerwinski, Michael; Spence, Jason R
2017-01-05
Recently in Nature, Gjorevski et al. (2016) describe a fully defined synthetic hydrogel that mimics the extracellular matrix to support in vitro growth of intestinal stem cells and organoids. The hydrogel allows exquisite control over the chemical and physical in vitro niche and enables identification of regulatory properties of the matrix. Copyright © 2017 Elsevier Inc. All rights reserved.
The Matrix Organization Revisited
DEFF Research Database (Denmark)
Gattiker, Urs E.; Ulhøi, John Parm
1999-01-01
This paper gives a short overview of matrix structure and technology management. It outlines some of the characteristics and also points out that many organizations may actualy be hybrids (i.e. mix several ways of organizing to allocate resorces effectively).......This paper gives a short overview of matrix structure and technology management. It outlines some of the characteristics and also points out that many organizations may actualy be hybrids (i.e. mix several ways of organizing to allocate resorces effectively)....
Matrix Extracellular Phosphoglycoprotein Inhibits Phosphate Transport
Marks, J; Churchill, L J; Debnam, E. S.; Unwin, R J
2008-01-01
The role of putative humoral factors, known as phosphatonins, in phosphate homeostasis and the relationship between phosphate handling by the kidney and gastrointestinal tract are incompletely understood. Matrix extracellular phosphoglycoprotein (MEPE), one of several candidate phosphatonins, promotes phosphaturia, but whether it also affects intestinal phosphate absorption is unknown. Here, using the in situ intestinal loop technique, we demonstrated that short-term infusion of MEPE inhibits...
DEFF Research Database (Denmark)
Povlsen, Lene; Borup, I.
2015-01-01
In 1953 when the Nordic School of Public Health was founded, the aim of public health programmes was disease prevention more than health promotion. This was not unusual, since at this time health usually was seen as the opposite of disease and illness. However, with the Ottawa Charter of 1986......, the World Health Organization made a crucial change to view health not as a goal in itself but as the means to a full life. In this way, health promotion became a first priority and fundamental action for the modern society. This insight eventually reached NHV and in 2002 - 50 years after the foundation...... - an associate professorship was established with a focus on health promotion. Nevertheless, the concept of health promotion had been integrated with or mentioned in courses run prior to the new post. Subsequently, a wide spectrum of courses in health promotion was introduced, such as Empowerment for Child...
Directory of Open Access Journals (Sweden)
J. Mukerji
1993-10-01
Full Text Available The present state of the knowledge of ceramic-matrix composites have been reviewed. The fracture toughness of present structural ceramics are not enough to permit design of high performance machines with ceramic parts. They also fail by catastrophic brittle fracture. It is generally believed that further improvement of fracture toughness is only possible by making composites of ceramics with ceramic fibre, particulate or platelets. Only ceramic-matrix composites capable of working above 1000 degree centigrade has been dealt with keeping reinforced plastics and metal-reinforced ceramics outside the purview. The author has discussed the basic mechanisms of toughening and fabrication of composites and the difficulties involved. Properties of available fibres and whiskers have been given. The best results obtained so far have been indicated. The limitations of improvement in properties of ceramic-matrix composites have been discussed.
Energy Technology Data Exchange (ETDEWEB)
Pan, Feng [Los Alamos National Laboratory; Kasiviswanathan, Shiva [Los Alamos National Laboratory
2010-01-01
In the matrix interdiction problem, a real-valued matrix and an integer k is given. The objective is to remove k columns such that the sum over all rows of the maximum entry in each row is minimized. This combinatorial problem is closely related to bipartite network interdiction problem which can be applied to prioritize the border checkpoints in order to minimize the probability that an adversary can successfully cross the border. After introducing the matrix interdiction problem, we will prove the problem is NP-hard, and even NP-hard to approximate with an additive n{gamma} factor for a fixed constant {gamma}. We also present an algorithm for this problem that achieves a factor of (n-k) mUltiplicative approximation ratio.
Extracellular matrix structure.
Theocharis, Achilleas D; Skandalis, Spyros S; Gialeli, Chrysostomi; Karamanos, Nikos K
2016-02-01
Extracellular matrix (ECM) is a non-cellular three-dimensional macromolecular network composed of collagens, proteoglycans/glycosaminoglycans, elastin, fibronectin, laminins, and several other glycoproteins. Matrix components bind each other as well as cell adhesion receptors forming a complex network into which cells reside in all tissues and organs. Cell surface receptors transduce signals into cells from ECM, which regulate diverse cellular functions, such as survival, growth, migration, and differentiation, and are vital for maintaining normal homeostasis. ECM is a highly dynamic structural network that continuously undergoes remodeling mediated by several matrix-degrading enzymes during normal and pathological conditions. Deregulation of ECM composition and structure is associated with the development and progression of several pathologic conditions. This article emphasizes in the complex ECM structure as to provide a better understanding of its dynamic structural and functional multipotency. Where relevant, the implication of the various families of ECM macromolecules in health and disease is also presented.
Finite Temperature Matrix Theory
Meana, M L; Peñalba, J P; Meana, Marco Laucelli; Peñalba, Jesús Puente
1998-01-01
We present the way the Lorentz invariant canonical partition function for Matrix Theory as a light-cone formulation of M-theory can be computed. We explicitly show how when the eleventh dimension is decompactified, the N=1 eleven dimensional SUGRA partition function appears. From this particular analysis we also clarify the question about the discernibility problem when making statistics with supergravitons (the N! problem) in Matrix black hole configurations. We also provide a high temperature expansion which captures some structure of the canonical partition function when interactions amongst D-particles are on. The connection with the semi-classical computations thermalizing the open superstrings attached to a D-particle is also clarified through a Born-Oppenheimer approximation. Some ideas about how Matrix Theory would describe the complementary degrees of freedom of the massless content of eleven dimensional SUGRA are also discussed.
Matrixed business support comparison study.
Energy Technology Data Exchange (ETDEWEB)
Parsons, Josh D.
2004-11-01
The Matrixed Business Support Comparison Study reviewed the current matrixed Chief Financial Officer (CFO) division staff models at Sandia National Laboratories. There were two primary drivers of this analysis: (1) the increasing number of financial staff matrixed to mission customers and (2) the desire to further understand the matrix process and the opportunities and challenges it creates.
Aoki, H; Kawai, H; Kitazawa, Y; Tada, T; Tsuchiya, A
1999-01-01
We review our proposal for a constructive definition of superstring, type IIB matrix model. The IIB matrix model is a manifestly covariant model for space-time and matter which possesses N=2 supersymmetry in ten dimensions. We refine our arguments to reproduce string perturbation theory based on the loop equations. We emphasize that the space-time is dynamically determined from the eigenvalue distributions of the matrices. We also explain how matter, gauge fields and gravitation appear as fluctuations around dynamically determined space-time.
Kitazawa, Y; Saito, O; Kitazawa, Yoshihisa; Mizoguchi, Shun'ya; Saito, Osamu
2006-01-01
We study the zero-dimensional reduced model of D=6 pure super Yang-Mills theory and argue that the large N limit describes the (2,0) Little String Theory. The one-loop effective action shows that the force exerted between two diagonal blocks of matrices behaves as 1/r^4, implying a six-dimensional spacetime. We also observe that it is due to non-gravitational interactions. We construct wave functions and vertex operators which realize the D=6, (2,0) tensor representation. We also comment on other "little" analogues of the IIB matrix model and Matrix Theory with less supercharges.
Hohn, Franz E
2012-01-01
This complete and coherent exposition, complemented by numerous illustrative examples, offers readers a text that can teach by itself. Fully rigorous in its treatment, it offers a mathematically sound sequencing of topics. The work starts with the most basic laws of matrix algebra and progresses to the sweep-out process for obtaining the complete solution of any given system of linear equations - homogeneous or nonhomogeneous - and the role of matrix algebra in the presentation of useful geometric ideas, techniques, and terminology.Other subjects include the complete treatment of the structur
Rheocasting Al Matrix Composites
Girot, F. A.; Albingre, L.; Quenisset, J. M.; Naslain, R.
1987-11-01
Aluminum alloy matrix composites reinforced by SiC short fibers (or whiskers) can be prepared by rheocasting, a process which consists of the incorporation and homogeneous distribution of the reinforcement by stirring within a semi-solid alloy. Using this technique, composites containing fiber volume fractions in the range of 8-15%, have been obtained for various fibers lengths (i.e., 1 mm, 3 mm and 6 mm for SiC fibers). This paper attempts to delineate the best compocasting conditions for aluminum matrix composites reinforced by short SiC (e.g Nicalon) or SiC whiskers (e.g., Tokamax) and characterize the resulting microstructures.
Frahm, K M
2016-01-01
Using parallels with the quantum scattering theory, developed for processes in nuclear and mesoscopic physics and quantum chaos, we construct a reduced Google matrix $G_R$ which describes the properties and interactions of a certain subset of selected nodes belonging to a much larger directed network. The matrix $G_R$ takes into account effective interactions between subset nodes by all their indirect links via the whole network. We argue that this approach gives new possibilities to analyze effective interactions in a group of nodes embedded in a large directed networks. Possible efficient numerical methods for the practical computation of $G_R$ are also described.
Density matrix perturbation theory.
Niklasson, Anders M N; Challacombe, Matt
2004-05-14
An orbital-free quantum perturbation theory is proposed. It gives the response of the density matrix upon variation of the Hamiltonian by quadratically convergent recursions based on perturbed projections. The technique allows treatment of embedded quantum subsystems with a computational cost scaling linearly with the size of the perturbed region, O(N(pert.)), and as O(1) with the total system size. The method allows efficient high order perturbation expansions, as demonstrated with an example involving a 10th order expansion. Density matrix analogs of Wigner's 2n+1 rule are also presented.
Energy Technology Data Exchange (ETDEWEB)
Brown, T.W.
2010-11-15
The same complex matrix model calculates both tachyon scattering for the c=1 non-critical string at the self-dual radius and certain correlation functions of half-BPS operators in N=4 super- Yang-Mills. It is dual to another complex matrix model where the couplings of the first model are encoded in the Kontsevich-like variables of the second. The duality between the theories is mirrored by the duality of their Feynman diagrams. Analogously to the Hermitian Kontsevich- Penner model, the correlation functions of the second model can be written as sums over discrete points in subspaces of the moduli space of punctured Riemann surfaces. (orig.)
DEFF Research Database (Denmark)
Frandsen, Gudmund Skovbjerg; Frandsen, Peter Frands
2009-01-01
We consider maintaining information about the rank of a matrix under changes of the entries. For n×n matrices, we show an upper bound of O(n1.575) arithmetic operations and a lower bound of Ω(n) arithmetic operations per element change. The upper bound is valid when changing up to O(n0.575) entri...... closed fields. The upper bound for element updates uses fast rectangular matrix multiplication, and the lower bound involves further development of an earlier technique for proving lower bounds for dynamic computation of rational functions.......We consider maintaining information about the rank of a matrix under changes of the entries. For n×n matrices, we show an upper bound of O(n1.575) arithmetic operations and a lower bound of Ω(n) arithmetic operations per element change. The upper bound is valid when changing up to O(n0.575) entries...... in a single column of the matrix. We also give an algorithm that maintains the rank using O(n2) arithmetic operations per rank one update. These bounds appear to be the first nontrivial bounds for the problem. The upper bounds are valid for arbitrary fields, whereas the lower bound is valid for algebraically...
Empirical codon substitution matrix
Directory of Open Access Journals (Sweden)
Gonnet Gaston H
2005-06-01
Full Text Available Abstract Background Codon substitution probabilities are used in many types of molecular evolution studies such as determining Ka/Ks ratios, creating ancestral DNA sequences or aligning coding DNA. Until the recent dramatic increase in genomic data enabled construction of empirical matrices, researchers relied on parameterized models of codon evolution. Here we present the first empirical codon substitution matrix entirely built from alignments of coding sequences from vertebrate DNA and thus provide an alternative to parameterized models of codon evolution. Results A set of 17,502 alignments of orthologous sequences from five vertebrate genomes yielded 8.3 million aligned codons from which the number of substitutions between codons were counted. From this data, both a probability matrix and a matrix of similarity scores were computed. They are 64 × 64 matrices describing the substitutions between all codons. Substitutions from sense codons to stop codons are not considered, resulting in block diagonal matrices consisting of 61 × 61 entries for the sense codons and 3 × 3 entries for the stop codons. Conclusion The amount of genomic data currently available allowed for the construction of an empirical codon substitution matrix. However, more sequence data is still needed to construct matrices from different subsets of DNA, specific to kingdoms, evolutionary distance or different amount of synonymous change. Codon mutation matrices have advantages for alignments up to medium evolutionary distances and for usages that require DNA such as ancestral reconstruction of DNA sequences and the calculation of Ka/Ks ratios.
Matrix Embedded Organic Synthesis
Kamakolanu, U. G.; Freund, F. T.
2016-05-01
In the matrix of minerals such as olivine, a redox reaction of the low-z elements occurs. Oxygen is oxidized to the peroxy state while the low-Z-elements become chemically reduced. We assign them a formula [CxHyOzNiSj]n- and call them proto-organics.
A Classification Matrix of Examination Items to Promote Transformative Assessment
McMahon, Mark; Garrett, Michael
2016-01-01
The ability to assess learning hinges on the quality of the instruments that are used. This paper reports on the first stage of the design of software to assist educators in ensuring assessment questions meet educational outcomes. A review of the literature within the field of instructional psychology was undertaken with a view towards…
Traction Force Microscopy in 3-Dimensional Extracellular Matrix Networks.
Cóndor, M; Steinwachs, J; Mark, C; García-Aznar, J M; Fabry, B
2017-06-19
Cell migration through a three-dimensional (3-D) matrix depends strongly on the ability of cells to generate traction forces. To overcome the steric hindrance of the matrix, cells need to generate sufficiently high traction forces but also need to distribute these forces spatially in a migration-promoting way. This unit describes a protocol to measure spatial maps of cell traction forces in 3-D biopolymer networks such as collagen, fibrin, or Matrigel. Traction forces are computed from the relationship between measured force-induced matrix deformations surrounding the cell and the known mechanical properties of the matrix. The method does not rely on knowledge of the cell surface coordinates and takes nonlinear mechanical properties of the matrix into account. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.
Li, Qin; Zhao, Yongxin; Wu, Xiaofeng; Liu, Si
There can be multitudinous models specifying aspects of the same system. Each model has a bias towards one aspect. These models often override in specific aspects though they have different expressions. A specification written in one model can be refined by introducing additional information from other models. The paper proposes a concept of promoting models which is a methodology to obtain refinements with support from cooperating models. It refines a primary model by integrating the information from a secondary model. The promotion principle is not merely an academic point, but also a reliable and robust engineering technique which can be used to develop software and hardware systems. It can also check the consistency between two specifications from different models. A case of modeling a simple online shopping system with the cooperation of the guarded design model and CSP model illustrates the practicability of the promotion principle.
Assembly and development of the Pseudomonas aeruginosa biofilm matrix.
Directory of Open Access Journals (Sweden)
Luyan Ma
2009-03-01
Full Text Available Virtually all cells living in multicellular structures such as tissues and organs are encased in an extracellular matrix. One of the most important features of a biofilm is the extracellular polymeric substance that functions as a matrix, holding bacterial cells together. Yet very little is known about how the matrix forms or how matrix components encase bacteria during biofilm development. Pseudomonas aeruginosa forms environmentally and clinically relevant biofilms and is a paradigm organism for the study of biofilms. The extracellular polymeric substance of P. aeruginosa biofilms is an ill-defined mix of polysaccharides, nucleic acids, and proteins. Here, we directly visualize the product of the polysaccharide synthesis locus (Psl exopolysaccharide at different stages of biofilm development. During attachment, Psl is anchored on the cell surface in a helical pattern. This promotes cell-cell interactions and assembly of a matrix, which holds bacteria in the biofilm and on the surface. Chemical dissociation of Psl from the bacterial surface disrupted the Psl matrix as well as the biofilm structure. During biofilm maturation, Psl accumulates on the periphery of 3-D-structured microcolonies, resulting in a Psl matrix-free cavity in the microcolony center. At the dispersion stage, swimming cells appear in this matrix cavity. Dead cells and extracellular DNA (eDNA are also concentrated in the Psl matrix-free area. Deletion of genes that control cell death and autolysis affects the formation of the matrix cavity and microcolony dispersion. These data provide a mechanism for how P. aeruginosa builds a matrix and subsequently a cavity to free a portion of cells for seeding dispersal. Direct visualization reveals that Psl is a key scaffolding matrix component and opens up avenues for therapeutics of biofilm-related complications.
Dijkgraaf, Robbert; Verlinde, Erik; Verlinde, Herman
1997-02-01
Via compactification on a circle, the matrix mode] of M-theory proposed by Banks et a]. suggests a concrete identification between the large N limit of two-dimensional N = 8 supersymmetric Yang-Mills theory and type IIA string theory. In this paper we collect evidence that supports this identification. We explicitly identify the perturbative string states and their interactions, and describe the appearance of D-particle and D-membrane states.
Energy Technology Data Exchange (ETDEWEB)
Dijkgraaf, R. [Amsterdam Univ. (Netherlands). Dept. of Mathematics; Verlinde, E. [TH-Division, CERN, CH-1211 Geneva 23 (Switzerland)]|[Institute for Theoretical Physics, Universtity of Utrecht, 3508 TA Utrecht (Netherlands); Verlinde, H. [Institute for Theoretical Physics, University of Amsterdam, 1018 XE Amsterdam (Netherlands)
1997-09-01
Via compactification on a circle, the matrix model of M-theory proposed by Banks et al. suggests a concrete identification between the large N limit of two-dimensional N=8 supersymmetric Yang-Mills theory and type IIA string theory. In this paper we collect evidence that supports this identification. We explicitly identify the perturbative string states and their interactions, and describe the appearance of D-particle and D-membrane states. (orig.).
Dijkgraaf, R; Verlinde, Herman L
1997-01-01
Via compactification on a circle, the matrix model of M-theory proposed by Banks et al suggests a concrete identification between the large N limit of two-dimensional N=8 supersymmetric Yang-Mills theory and type IIA string theory. In this paper we collect evidence that supports this identification. We explicitly identify the perturbative string states and their interactions, and describe the appearance of D-particle and D-membrane states.
Felder, G; Felder, Giovanni; Riser, Roman
2004-01-01
We study a class of holomorphic matrix models. The integrals are taken over middle dimensional cycles in the space of complex square matrices. As the size of the matrices tends to infinity, the distribution of eigenvalues is given by a measure with support on a collection of arcs in the complex planes. We show that the arcs are level sets of the imaginary part of a hyperelliptic integral connecting branch points.
Matrix groups for undergraduates
Tapp, Kristopher
2016-01-01
Matrix groups touch an enormous spectrum of the mathematical arena. This textbook brings them into the undergraduate curriculum. It makes an excellent one-semester course for students familiar with linear and abstract algebra and prepares them for a graduate course on Lie groups. Matrix Groups for Undergraduates is concrete and example-driven, with geometric motivation and rigorous proofs. The story begins and ends with the rotations of a globe. In between, the author combines rigor and intuition to describe the basic objects of Lie theory: Lie algebras, matrix exponentiation, Lie brackets, maximal tori, homogeneous spaces, and roots. This second edition includes two new chapters that allow for an easier transition to the general theory of Lie groups. From reviews of the First Edition: This book could be used as an excellent textbook for a one semester course at university and it will prepare students for a graduate course on Lie groups, Lie algebras, etc. … The book combines an intuitive style of writing w...
Directory of Open Access Journals (Sweden)
Pradeep K. Rohatgi
1993-10-01
Full Text Available This paper reviews the world wide upsurge in metal matrix composite research and development activities with particular emphasis on cast metal-matrix particulate composites. Extensive applications of cast aluminium alloy MMCs in day-to-day use in transportation as well as durable good industries are expected to advance rapidly in the next decade. The potential for extensive application of cast composites is very large in India, especially in the areas of transportation, energy and electromechanical machinery; the extensive use of composites can lead to large savings in materials and energy, and in several instances, reduce environmental pollution. It is important that engineering education and short-term courses be organized to bring MMCs to the attention of students and engineering industry leaders. India already has excellent infrastructure for development of composites, and has a long track record of world class research in cast metal matrix particulate composites. It is now necessary to catalyze prototype and regular production of selected composite components, and get them used in different sectors, especially railways, cars, trucks, buses, scooters and other electromechanical machinery. This will require suitable policies backed up by funding to bring together the first rate talent in cast composites which already exists in India, to form viable development groups followed by setting up of production plants involving the process engineering capability already available within the country. On the longer term, cast composites should be developed for use in energy generation equipment, electronic packaging aerospace systems, and smart structures.
Matrix Theory of Small Oscillations
Chavda, L. K.
1978-01-01
A complete matrix formulation of the theory of small oscillations is presented. Simple analytic solutions involving matrix functions are found which clearly exhibit the transients, the damping factors, the Breit-Wigner form for resonances, etc. (BB)
Matrix Completions and Chordal Graphs
Institute of Scientific and Technical Information of China (English)
Kenneth John HARRISON
2003-01-01
In a matrix-completion problem the aim is to specifiy the missing entries of a matrix inorder to produce a matrix with particular properties. In this paper we survey results concerning matrix-completion problems where we look for completions of various types for partial matrices supported ona given pattern. We see that thc existence of completions of the required type often depends on thechordal properties of graphs associated with the pattern.
THE GENERALIZED POLARIZATION SCATTERING MATRIX
the Least Square Best Estimate of the Generalized Polarization matrix from a set of measurements is then developed. It is shown that the Faraday...matrix data. It is then shown that the Least Square Best Estimate of the orientation angle of a symmetric target is also determinable from Faraday rotation contaminated short pulse monostatic polarization matrix data.
Promoter-mediated transcriptional dynamics.
Zhang, Jiajun; Zhou, Tianshou
2014-01-21
Genes in eukaryotic cells are typically regulated by complex promoters containing multiple binding sites for a variety of transcription factors, but how promoter dynamics affect transcriptional dynamics has remained poorly understood. In this study, we analyze gene models at the transcriptional regulation level, which incorporate the complexity of promoter structure (PS) defined as transcriptional exits (i.e., ON states of the promoter) and the transition pattern (described by a matrix consisting of transition rates among promoter activity states). We show that multiple exits of transcription are the essential origin of generating multimodal distributions of mRNA, but promoters with the same transition pattern can lead to multimodality of different modes, depending on the regulation of transcriptional factors. In turn, for similar mRNA distributions in the models, the mean ON or OFF time distributions may exhibit different characteristics, thus providing the supplemental information on PS. In addition, we demonstrate that the transcriptional noise can be characterized by a nonlinear function of mean ON and OFF times. These results not only reveal essential characteristics of promoter-mediated transcriptional dynamics but also provide signatures useful for inferring PS based on characteristics of transcriptional outputs. Copyright © 2014 Biophysical Society. Published by Elsevier Inc. All rights reserved.
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
Matrix string partition function
Kostov, Ivan K; Kostov, Ivan K.; Vanhove, Pierre
1998-01-01
We evaluate quasiclassically the Ramond partition function of Euclidean D=10 U(N) super Yang-Mills theory reduced to a two-dimensional torus. The result can be interpreted in terms of free strings wrapping the space-time torus, as expected from the point of view of Matrix string theory. We demonstrate that, when extrapolated to the ultraviolet limit (small area of the torus), the quasiclassical expressions reproduce exactly the recently obtained expression for the partition of the completely reduced SYM theory, including the overall numerical factor. This is an evidence that our quasiclassical calculation might be exact.
Eisenman, Richard L
2005-01-01
This outstanding text and reference applies matrix ideas to vector methods, using physical ideas to illustrate and motivate mathematical concepts but employing a mathematical continuity of development rather than a physical approach. The author, who taught at the U.S. Air Force Academy, dispenses with the artificial barrier between vectors and matrices--and more generally, between pure and applied mathematics.Motivated examples introduce each idea, with interpretations of physical, algebraic, and geometric contexts, in addition to generalizations to theorems that reflect the essential structur
Deift, Percy
2009-01-01
This book features a unified derivation of the mathematical theory of the three classical types of invariant random matrix ensembles-orthogonal, unitary, and symplectic. The authors follow the approach of Tracy and Widom, but the exposition here contains a substantial amount of additional material, in particular, facts from functional analysis and the theory of Pfaffians. The main result in the book is a proof of universality for orthogonal and symplectic ensembles corresponding to generalized Gaussian type weights following the authors' prior work. New, quantitative error estimates are derive
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.
Matrix algebra for linear models
Gruber, Marvin H J
2013-01-01
Matrix methods have evolved from a tool for expressing statistical problems to an indispensable part of the development, understanding, and use of various types of complex statistical analyses. This evolution has made matrix methods a vital part of statistical education. Traditionally, matrix methods are taught in courses on everything from regression analysis to stochastic processes, thus creating a fractured view of the topic. Matrix Algebra for Linear Models offers readers a unique, unified view of matrix analysis theory (where and when necessary), methods, and their applications. Written f
Directory of Open Access Journals (Sweden)
Linda Christian Carrijo-Carvalho
2012-01-01
Full Text Available Lipocalin family members have been implicated in development, regeneration, and pathological processes, but their roles are unclear. Interestingly, these proteins are found abundant in the venom of the Lonomia obliqua caterpillar. Lipocalins are β-barrel proteins, which have three conserved motifs in their amino acid sequence. One of these motifs was shown to be a sequence signature involved in cell modulation. The aim of this study is to investigate the effects of a synthetic peptide comprising the lipocalin sequence motif in fibroblasts. This peptide suppressed caspase 3 activity and upregulated Bcl-2 and Ki-67, but did not interfere with GPCR calcium mobilization. Fibroblast responses also involved increased expression of proinflammatory mediators. Increase of extracellular matrix proteins, such as collagen, fibronectin, and tenascin, was observed. Increase in collagen content was also observed in vivo. Results indicate that modulation effects displayed by lipocalins through this sequence motif involve cell survival, extracellular matrix remodeling, and cytokine signaling. Such effects can be related to the lipocalin roles in disease, development, and tissue repair.
Institute of Scientific and Technical Information of China (English)
陈刚; 白建华; 朱新锋; 曹俊; 刘其雨; 赵英鹏; 李立
2015-01-01
BACKGROUND:Acelular dermal matrix is a cel-free natural tissue scaffold similar to human soft tissue, which is easy to shape and has non-toxic side effects. It has been used to repair the urethra and ureter. OBJECTIVE:To investigate the effect of acelular dermal matrix on the repair of bile duct injury. METHODS:Thirty Diannan miniature pigs were randomly divided into three groups: in blank group, the bile duct was resected folowed by end to end anastomosis; in experimental group, bile duct defect model was made folowed by repair with acelular dermal matrix; in control group, bile duct defect model was made folowed by repair with expanded polytetrafluoroethylene. At 6 and 24 weeks after repair, bile duct patches and surrounding tissues were taken for immunohistochemical observation and RT-PCR detection. RESULTS AND CONCLUSION: Compared with the control and blank group, the expression of cytokeratin was higher, but the expression of transforming growth factor β1 was lower in the experimental group. Within 24 weeks after repair, the total mRNA level of transforming growth factor β1 was lower in the experimental group than the other two groups (P < 0.05), but the total mRNA levels of insulin-like growth factor 2 and vascular endothelial growth factor were higher in the experimental group (P < 0.05). These findings indicate that the acelular dermal matrix for repair of bile duct injury can promote angiogenesis and bile duct epithelial regeneration, but not increase the formation of scars.%背景：脱细胞真皮基质是无细胞的天然组织支架，与人体软组织十分相近，易于塑形，无毒副作用，已被用于修补尿道与输尿管。目的：观察脱细胞基质修补胆管损伤的效果。方法：将30头滇南小耳猪随机均分为3组，空白对照组切断胆管后行端端吻合，实验组人为制作胆管缺损后以脱细胞真皮基质修补，对照组人为制作胆管缺损后以膨体聚四氟乙烯修补。修补后6，24
Matrix Quantization of Turbulence
Floratos, Emmanuel
2011-01-01
Based on our recent work on Quantum Nambu Mechanics $\\cite{af2}$, we provide an explicit quantization of the Lorenz chaotic attractor through the introduction of Non-commutative phase space coordinates as Hermitian $ N \\times N $ matrices in $ R^{3}$. For the volume preserving part, they satisfy the commutation relations induced by one of the two Nambu Hamiltonians, the second one generating a unique time evolution. Dissipation is incorporated quantum mechanically in a self-consistent way having the correct classical limit without the introduction of external degrees of freedom. Due to its volume phase space contraction it violates the quantum commutation relations. We demonstrate that the Heisenberg-Nambu evolution equations for the Matrix Lorenz system develop fast decoherence to N independent Lorenz attractors. On the other hand there is a weak dissipation regime, where the quantum mechanical properties of the volume preserving non-dissipative sector survive for long times.
Velasco, Pedro Pablo Perez
2008-01-01
This book objective is to develop an algebraization of graph grammars. Equivalently, we study graph dynamics. From the point of view of a computer scientist, graph grammars are a natural generalization of Chomsky grammars for which a purely algebraic approach does not exist up to now. A Chomsky (or string) grammar is, roughly speaking, a precise description of a formal language (which in essence is a set of strings). On a more discrete mathematical style, it can be said that graph grammars -- Matrix Graph Grammars in particular -- study dynamics of graphs. Ideally, this algebraization would enforce our understanding of grammars in general, providing new analysis techniques and generalizations of concepts, problems and results known so far.
Dimiev, Stancho; Stoev, Peter; Stoilova, Stanislava
2013-12-01
The notion of anticirculant is ordinary of interest for specialists of general algebra (to see for instance [1]). In this paper we develop some aspects of anticirculants in real function theory. Denoting by X≔x0+jx1+⋯+jmxm, xk∈R, m+1 = 2n, and jk is the k-th degree of the matrix j = (0100...00010...00001...0..................-1000...0), we study the functional anticirculants f(X)≔f0(x0,x1,...,xm)+jf1(x0,x1,...,xm)+⋯+jm-1fm-1(x0,x1,...,xm)+jmfm(x0,x1,...,xm), where fk(x0,x1,...,xm) are smooth functions of 2n real variables. A continuation for complex function theory will appear.
Energy Technology Data Exchange (ETDEWEB)
Hastings, Matthew B [Los Alamos National Laboratory
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.
Matrix membranes and integrability
Energy Technology Data Exchange (ETDEWEB)
Zachos, C. [Argonne National Lab., IL (United States); Fairlie, D. [University of Durham (United Kingdom). Dept. of Mathematical Sciences; Curtright, T. [University of Miami, Coral Gables, FL (United States). Dept. of Physics
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.
The extracellular matrix in breast cancer.
Insua-Rodríguez, Jacob; Oskarsson, Thordur
2016-02-01
The extracellular matrix (ECM) is increasingly recognized as an important regulator in breast cancer. ECM in breast cancer development features numerous changes in composition and organization when compared to the mammary gland under homeostasis. Matrix proteins that are induced in breast cancer include fibrillar collagens, fibronectin, specific laminins and proteoglycans as well as matricellular proteins. Growing evidence suggests that many of these induced ECM proteins play a major functional role in breast cancer progression and metastasis. A number of the induced ECM proteins have moreover been shown to be essential components of metastatic niches, promoting stem/progenitor signaling pathways and metastatic growth. ECM remodeling enzymes are also markedly increased, leading to major changes in the matrix structure and biomechanical properties. Importantly, several ECM components and ECM remodeling enzymes are specifically induced in breast cancer or during tissue regeneration while healthy tissues under homeostasis express exceedingly low levels. This may indicate that ECM and ECM-associated functions may represent promising drug targets against breast cancer, providing important specificity that could be utilized when developing therapies. Copyright © 2015 Elsevier B.V. All rights reserved.
Directory of Open Access Journals (Sweden)
Anisha Kumar
2014-01-01
In one-step apexification using MTA, the technical problem encountered is controlling the overfill or underfill of MTA. The use of a matrix material helps to overcome this shortcoming. Platelet rich fibrin (PRF is an immune platelet concentrate, which can be used as a matrix, it also promotes wound healing and repair. This case report presents a case of one step apexification using MTA as an apical barrier and autologous PRF as an internal matrix.
Spherical membranes in Matrix theory
Kabat, D; Kabat, Daniel; Taylor, Washington
1998-01-01
We consider membranes of spherical topology in uncompactified Matrix theory. In general for large membranes Matrix theory reproduces the classical membrane dynamics up to 1/N corrections; for certain simple membrane configurations, the equations of motion agree exactly at finite N. We derive a general formula for the one-loop Matrix potential between two finite-sized objects at large separations. Applied to a graviton interacting with a round spherical membrane, we show that the Matrix potential agrees with the naive supergravity potential for large N, but differs at subleading orders in N. The result is quite general: we prove a pair of theorems showing that for large N, after removing the effects of gravitational radiation, the one-loop potential between classical Matrix configurations agrees with the long-distance potential expected from supergravity. As a spherical membrane shrinks, it eventually becomes a black hole. This provides a natural framework to study Schwarzschild black holes in Matrix theory.
Institute of Scientific and Technical Information of China (English)
王德金; 任满意; 陈慧娜; 王旭平; 隋树建
2011-01-01
目的 研究肿瘤坏死因子样凋亡微弱诱导剂(TWEAK)影响大鼠心肌成纤维细胞(CFs)增殖和胶原合成的作用机制.方法 采用胰酶消化法培养新生Wistar大鼠CFs,加入重组人TWEAK(rhTWEAK)和NF-κB抑制剂PDTC干预,qRT-PCR检测核转录因子NF-κB和金属蛋白酶9(MMP9)mRNA,Western blot检测NF-κB和MMP9蛋白表达,四甲基偶氮唑蓝(MTT)法测定细胞增殖.结果 rhTWEAK作用后NF-κB和MMP9 mRNA表达上调,同时蛋白表达明显增加,PDTC可抑制MMP9蛋白表达和细胞增殖.结论 TWEAK可通过NF-κB途径促进大鼠心肌成纤维细胞表达MMP9.%Objective To investigate the mechanism and effects of tumor necrosis factor-like weak inducer of apoptosis (TWEAK) on the proliferation and collagen synthesis in cultured rat cardiac fibroblasts (CFs). Methods Cultured CFs from neonatal Wistar rats were isolated by trypsinization and treated with recombinant human TWEAK (rhT-WEAK) and PDTC( NF-kB specific inhibitor). mRNA and protein expressions of NF-kB and MMP9 were detected by qRT-PCR and Western blot, respectively. CFs proliferation was examined by MTT. Results rhTWEAK significantly elevated mRNA and protein expressions of NF-kB and MMP9. PDTC could inhibit MMP9 protein expression and CFs proliferation induced by NF-kB's activation. Conclusion TWEAK can promote expressions of matrix metalloprotein-ase 9 in rat cardiac fibroblasts via the NF-kB pathway.
The Effects of Extracellular Matrix on Tissue Engineering Construction of Cartilage in Vitro
Institute of Scientific and Technical Information of China (English)
YU Li; LI Fa-tao; TANG Ming-qiao; YAN Wei-qun
2006-01-01
The effects of various cartilage extracellular matrix on the construction of rabbit growth plate cartilage tissue in vitro were studied. The results show that collagen, proteoglycan and hyaluronic acid can promote the growth of cultured chondrocytes but the effects of various cartilage extracellular matrix(ECM)on chondrocyte differentiation are different. Collagen can promote the hypertrophy of chondrocytes while proteoglycan and hyaluronic acid inhibit the transition of mature chondrocytes into hypertrophied chondrocytes.
Linearized supergravity from Matrix theory
Kabat, D; Kabat, Daniel; Taylor, Washington
1998-01-01
We show that the linearized supergravity potential between two objects arising from the exchange of quanta with zero longitudinal momentum is reproduced to all orders in 1/r by terms in the one-loop Matrix theory potential. The essential ingredient in the proof is the identification of the Matrix theory quantities corresponding to moments of the stress tensor and membrane current. We also point out that finite-N Matrix theory violates the Equivalence Principle.
Lectures on Matrix Field Theory
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.
Matrix elements of unstable states
Bernard, V; Meißner, U -G; Rusetsky, A
2012-01-01
Using the language of non-relativistic effective Lagrangians, we formulate a systematic framework for the calculation of resonance matrix elements in lattice QCD. The generalization of the L\\"uscher-Lellouch formula for these matrix elements is derived. We further discuss in detail the procedure of the analytic continuation of the resonance matrix elements into the complex energy plane and investigate the infinite-volume limit.
MacKaay, M A
1996-01-01
In order to construct a representation of the tangle category one needs an enhanced R-matrix. In this paper we define a sufficient and necessary condition for enhancement that can be checked easily for any R-matrix. If the R-matrix can be enhanced, we also show how to construct the additional data that define the enhancement. As a direct consequence we find a sufficient condition for the construction of a knot invariant.
Matrix Models and Gravitational Corrections
Dijkgraaf, R; Temurhan, M; Dijkgraaf, Robbert; Sinkovics, Annamaria; Temurhan, Mine
2002-01-01
We provide evidence of the relation between supersymmetric gauge theories and matrix models beyond the planar limit. We compute gravitational R^2 couplings in gauge theories perturbatively, by summing genus one matrix model diagrams. These diagrams give the leading 1/N^2 corrections in the large N limit of the matrix model and can be related to twist field correlators in a collective conformal field theory. In the case of softly broken SU(N) N=2 super Yang-Mills theories, we find that these exact solutions of the matrix models agree with results obtained by topological field theory methods.
Energy Technology Data Exchange (ETDEWEB)
Dorey, Nick [Department of Applied Mathematics and Theoretical Physics, University of Cambridge,Wilberforce Road, Cambridge, CB3 OWA (United Kingdom); Tong, David [Department of Applied Mathematics and Theoretical Physics, University of Cambridge,Wilberforce Road, Cambridge, CB3 OWA (United Kingdom); Department of Theoretical Physics, TIFR,Homi Bhabha Road, Mumbai 400 005 (India); Stanford Institute for Theoretical Physics,Via Pueblo, Stanford, CA 94305 (United States); Turner, Carl [Department of Applied Mathematics and Theoretical Physics, University of Cambridge,Wilberforce Road, Cambridge, CB3 OWA (United Kingdom)
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.
Dorey, Nick; Turner, Carl
2016-01-01
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.
Extended Matrix Variate Hypergeometric Functions and Matrix Variate Distributions
Directory of Open Access Journals (Sweden)
Daya K. Nagar
2015-01-01
Full Text Available Hypergeometric functions of matrix arguments occur frequently in multivariate statistical analysis. In this paper, we define and study extended forms of Gauss and confluent hypergeometric functions of matrix arguments and show that they occur naturally in statistical distribution theory.
Chan, Garnet Kin-Lic; Nakatani, Naoki; Li, Zhendong; White, Steven R
2016-01-01
Current descriptions of the ab initio 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 par...
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.
Michelson, J
2004-01-01
The Matrix Theory that has been proposed for various pp wave backgrounds is discussed. Particular emphasis is on the existence of novel nontrivial supersymmetric solutions of the Matrix Theory. These correspond to branes of various shapes (ellipsoidal, paraboloidal, and possibly hyperboloidal) that are unexpected from previous studies of branes in pp wave geometries.
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…
Machining of Metal Matrix Composites
2012-01-01
Machining of Metal Matrix Composites provides the fundamentals and recent advances in the study of machining of metal matrix composites (MMCs). Each chapter is written by an international expert in this important field of research. Machining of Metal Matrix Composites gives the reader information on machining of MMCs with a special emphasis on aluminium matrix composites. Chapter 1 provides the mechanics and modelling of chip formation for traditional machining processes. Chapter 2 is dedicated to surface integrity when machining MMCs. Chapter 3 describes the machinability aspects of MMCs. Chapter 4 contains information on traditional machining processes and Chapter 5 is dedicated to the grinding of MMCs. Chapter 6 describes the dry cutting of MMCs with SiC particulate reinforcement. Finally, Chapter 7 is dedicated to computational methods and optimization in the machining of MMCs. Machining of Metal Matrix Composites can serve as a useful reference for academics, manufacturing and materials researchers, manu...
Matrix Model Approach to Cosmology
Chaney, A; Stern, A
2015-01-01
We perform a systematic search for rotationally invariant cosmological solutions to matrix models, or more specifically the bosonic sector of Lorentzian 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 space-time surfaces, with an attached Poisson structure, which can be associated with closed, open or static cosmologies. 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 matrix resolution of cosmological singularities. 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 $d=3$ soluti...
Matrix convolution operators on groups
Chu, Cho-Ho
2008-01-01
In the last decade, convolution operators of matrix functions have received unusual attention due to their diverse applications. This monograph presents some new developments in the spectral theory of these operators. The setting is the Lp spaces of matrix-valued functions on locally compact groups. The focus is on the spectra and eigenspaces of convolution operators on these spaces, defined by matrix-valued measures. Among various spectral results, the L2-spectrum of such an operator is completely determined and as an application, the spectrum of a discrete Laplacian on a homogeneous graph is computed using this result. The contractivity properties of matrix convolution semigroups are studied and applications to harmonic functions on Lie groups and Riemannian symmetric spaces are discussed. An interesting feature is the presence of Jordan algebraic structures in matrix-harmonic functions.
Explicit examples of DIM constraints for network matrix models
Awata, Hidetoshi; Matsumoto, Takuya; Mironov, Andrei; Morozov, Alexei; Morozov, Andrey; Ohkubo, Yusuke; Zenkevich, Yegor
2016-01-01
Dotsenko-Fateev and Chern-Simons matrix models, which describe Nekrasov functions for SYM theories in different dimensions, are all incorporated into network matrix models with the hidden Ding-Iohara-Miki (DIM) symmetry. This lifting is especially simple for what we call balanced networks. Then, the Ward identities (known under the names of Virasoro/W-constraints or loop equations or regularity condition for qq-characters) are also promoted to the DIM level, where they all become corollaries of a single identity.
Extracellular Matrix Scaffolds for Tissue Engineering and Regenerative Medicine.
Yi, Sheng; Ding, Fei; Gong, Leiiei; Gu, Xiaosong
2017-01-01
The extracellular matrix is produced by the resident cells in tissues and organs, and secreted into the surrounding medium to provide biophysical and biochemical support to the surrounding cells due to its content of diverse bioactive molecules. Recently, the extracellular matrix has been used as a promising approach for tissue engineering. Emerging studies demonstrate that extracellular matrix scaffolds are able to create a favorable regenerative microenvironment, promote tissue-specific remodeling, and act as an inductive template for the repair and functional reconstruction of skin, bone, nerve, heart, lung, liver, kidney, small intestine, and other organs. In the current review, we will provide a critical overview of the structure and function of various types of extracellular matrix, the construction of three-dimensional extracellular matrix scaffolds, and their tissue engineering applications, with a focus on translation of these novel tissue engineered products to the clinic. We will also present an outlook on future perspectives of the extracellular matrix in tissue engineering and regenerative medicine. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.
Streptococcus mutans-derived extracellular matrix in cariogenic oral biofilms.
Klein, Marlise I; Hwang, Geelsu; Santos, Paulo H S; Campanella, Osvaldo H; Koo, Hyun
2015-01-01
Biofilms are highly structured microbial communities that are enmeshed in a self-produced extracellular matrix. Within the complex oral microbiome, Streptococcus mutans is a major producer of extracellular polymeric substances including exopolysaccharides (EPS), eDNA, and lipoteichoic acid (LTA). EPS produced by S. mutans-derived exoenzymes promote local accumulation of microbes on the teeth, while forming a spatially heterogeneous and diffusion-limiting matrix that protects embedded bacteria. The EPS-rich matrix provides mechanical stability/cohesiveness and facilitates the creation of highly acidic microenvironments, which are critical for the pathogenesis of dental caries. In parallel, S. mutans also releases eDNA and LTA, which can contribute with matrix development. eDNA enhances EPS (glucan) synthesis locally, increasing the adhesion of S. mutans to saliva-coated apatitic surfaces and the assembly of highly cohesive biofilms. eDNA and other extracellular substances, acting in concert with EPS, may impact the functional properties of the matrix and the virulence of cariogenic biofilms. Enhanced understanding about the assembly principles of the matrix may lead to efficacious approaches to control biofilm-related diseases.
Streptococcus mutans-derived extracellular matrix in cariogenic oral biofilms
Directory of Open Access Journals (Sweden)
Marlise eKlein
2015-02-01
Full Text Available Biofilms are highly structured microbial communities that are enmeshed in a self-produced extracellular matrix. Within the complex oral microbiome, Streptococcus mutans is a major producer of extracellular polymeric substances including exopolysaccharides (EPS, eDNA and lipoteichoic acid (LTA. EPS produced by S. mutans-derived exoenzymes promote local accumulation of microbes on the teeth, while forming a spatially heterogeneous and diffusion-limiting matrix that protects embedded bacteria. The EPS-rich matrix provides mechanical stability/cohesiveness and facilitates the creation of highly acidic microenvironments, which are critical for the pathogenesis of dental caries. In parallel, S. mutans also releases eDNA and LTA, which can contribute with matrix development. eDNA enhances EPS (glucan synthesis locally, increasing the adhesion of S. mutans to saliva-coated apatitic surfaces and the assembly of highly cohesive biofilms. eDNA and other extracellular substances, acting in concert with EPS, may impact the functional properties of the matrix and the virulence of cariogenic biofilms. Enhanced understanding about the assembly principles of the matrix may lead to efficacious approaches to control biofilm-related diseases.
Manufacturing Titanium Metal Matrix Composites by Consolidating Matrix Coated Fibres
Institute of Scientific and Technical Information of China (English)
Hua-Xin PENG
2005-01-01
Titanium metal matrix composites (TiMMCs) reinforced by continuous silicon carbide fibres are being developed for aerospace applications. TiMMCs manufactured by the consolidation of matrix-coated fibre (MCF) method offer optimum properties because of the resulting uniform fibre distribution, minimum fibre damage and fibre volume fraction control. In this paper, the consolidation of Ti-6Al-4V matrix-coated SiC fibres during vacuum hot pressing has been investigated. Experiments were carried out on multi-ply MCFs under vacuum hot pressing (VHP). In contrast to most of existing studies, the fibre arrangement has been carefully controlled either in square or hexagonal arraysthroughout the consolidated sample. This has enabled the dynamic consolidation behaviour of MCFs to be demonstrated by eliminating the fibre re-arrangement during the VHP process. The microstructural evolution of the matrix coating was reported and the deformation mechanisms involved were discussed.
New pole placement algorithm - Polynomial matrix approach
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.
High temperature polymer matrix composites
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.
Matrix Elements for Hylleraas CI
Harris, Frank E.
The limitation to at most a single interelectron distance in individual configurations of a Hylleraas-type multiconfiguration wave function restricts significantly the types of integrals occurring in matrix elements for energy calculations, but even then if the formulation is not handled efficiently the angular parts of these integrals escalate to create expressions of great complexity. This presentation reviews ways in which the angular-momentum calculus can be employed to systematize and simplify the matrix element formulas, particularly those for the kinetic-energy matrix elements.
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
2016-07-01
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.
National Oceanic and Atmospheric Administration, Department of Commerce — This data set was taken from CRD 08-18 at the NEFSC. Specifically, the Gulf of Maine diet matrix was developed for the EMAX exercise described in that center...
Linear connections on matrix geometries
Madore, J; Mourad, J; Madore, John; Masson, Thierry; Mourad, Jihad
1994-01-01
A general definition of a linear connection in noncommutative geometry has been recently proposed. Two examples are given of linear connections in noncommutative geometries which are based on matrix algebras. They both possess a unique metric connection.
Matrix Quantum Mechanics from Qubits
Hartnoll, Sean A; Mazenc, Edward A
2016-01-01
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.
Energy Technology Data Exchange (ETDEWEB)
Descouvemont, P; Baye, D [Physique Nucleaire Theorique et Physique Mathematique, C.P. 229, Universite Libre de Bruxelles (ULB), B 1050 Brussels (Belgium)], E-mail: pdesc@ulb.ac.be, E-mail: dbaye@ulb.ac.be
2010-03-15
The different facets of the R-matrix method are presented pedagogically in a general framework. Two variants have been developed over the years: (i) The 'calculable' R-matrix method is a calculational tool to derive scattering properties from the Schroedinger equation in a large variety of physical problems. It was developed rather independently in atomic and nuclear physics with too little mutual influence. (ii) The 'phenomenological' R-matrix method is a technique to parametrize various types of cross sections. It was mainly (or uniquely) used in nuclear physics. Both directions are explained by starting from the simple problem of scattering by a potential. They are illustrated by simple examples in nuclear and atomic physics. In addition to elastic scattering, the R-matrix formalism is applied to inelastic and radiative-capture reactions. We also present more recent and more ambitious applications of the theory in nuclear physics.
Matrix analysis of electrical machinery
Hancock, N N
2013-01-01
Matrix Analysis of Electrical Machinery, Second Edition is a 14-chapter edition that covers the systematic analysis of electrical machinery performance. This edition discusses the principles of various mathematical operations and their application to electrical machinery performance calculations. The introductory chapters deal with the matrix representation of algebraic equations and their application to static electrical networks. The following chapters describe the fundamentals of different transformers and rotating machines and present torque analysis in terms of the currents based on the p
Complex role of matrix metalloproteinases in angiogenesis
Institute of Scientific and Technical Information of China (English)
SANGQINGXIANGAMY
1998-01-01
Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) play a significant role in regulating angiogenesis,the process of new blood vessel formation.Interstitial collagenase (MMP-1),72kDa gelatinase A/type IV collagenase (MMP-2),and 92 kDA gelatinase B/type IV collagenase (MMP-9) dissolve extracellular matrix (ECM) and may initiate and promote angiogenesis.TIMP-1,TIMP-2,TIMP-3,and possibly,TIMP-4 inhibit neovascularization.A new paradign is emerging that matrilysin (MMP-7),MMP-9,and metalloelastase (MMP-12) may block angiogenesis by converting plasminogen to angiostatin,which is one of the most potent angiogenesis antagonists.MMPs and TIMPs play a complex role in regulating angiogenesis.An understanding of the biochemical and cellular pathways and mechanisms of angiogenesis will provide important information to allow the control of angiogenesis,e.g.the stimulation of angiogenesis for coronary collateral circulation formation;while the inhibition for treating arthritis and cancer.
Extracellular Matrix-Based Biohybrid Materials for Engineering Compliant, Matrix-Dense Tissues.
Bracaglia, Laura G; Fisher, John P
2015-11-18
An ideal tissue engineering scaffold should not only promote, but take an active role in, constructive remodeling and formation of site appropriate tissue. Extracellular matrix (ECM)-derived proteins provide unmatched cellular recognition, and therefore influence cellular response towards predicted remodeling behaviors. Materials built with only these proteins, however, can degrade rapidly or begin too weak to substitute for compliant, matrix-dense tissues. The focus of this Progress Report is on biohybrid materials that incorporate polymer components with ECM-derived proteins, to produce a substrate with desired mechanical and degradation properties, as well as actively guide tissue remodeling. Materials are described through four fabrication methods: 1) polymer and ECM-protein fibers woven together, 2) polymer and ECM proteins combined in a bilayer, 3) cell-built ECM on polymer scaffold, and 4) ECM proteins and polymers combined in a single hydrogel. Scaffolds from each fabrication method can achieve characteristics suitable for different types of tissue. In vivo testing has shown progressive remodeling in injury models, and suggests ECM-based biohybrid materials promote a prohealing immune response over single component alternatives. The prohealing immune response is associated with lasting success and long term host maintenance of the implant.
SVD row or column symmetric matrix
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
A new architecture for row or column symmetric matrix called extended matrix is defined, and a precise correspondence of the singular values and singular vectors between the extended matrix and its original (namely, the mother matrix) is derived. As an illustration of potential, we show that, for a class of extended matrices, the singular value decomposition using the mother matrix rather than the extended matrix per se can save the CPU time and memory without loss of numerical precision.
Citric Acid Capped Iron Oxide Nanoparticles as an Effective MALDI Matrix for Polymers
Liang, Qiaoli; Sherwood, Jennifer; Macher, Thomas; Wilson, Joseph M.; Bao, Yuping; Cassady, Carolyn J.
2016-12-01
A new matrix-assisted laser desorption ionization (MALDI) mass spectrometry matrix is proposed for molecular mass determination of polymers. This matrix contains an iron oxide nanoparticle (NP) core with citric acid (CA) molecules covalently bound to the surface. With the assistance of additives, the particulate nature of NPs allows the matrix to mix uniformly with polar or nonpolar polymer layers and promotes ionization, which may simplify matrix selection and sample preparation procedures. Several distinctively different polymer classes (polyethyleneglycol (PEG), polywax/polyethylene, perfluoropolyether, and polydimethylsiloxane) are effectively detected by the water or methanol dispersed NPCA matrix with NaCl, NaOH, LiOH, or AgNO3 as additives. Furtheremore, successful quantitative measurements of PEG1000 using polypropylene glycol 1000 as an internal standard are demonstrated.
Targeting the extracellular matrix to disrupt cancer progression
Freja Albjerg Venning; Lena eWullkopf; Janine T. Erler
2015-01-01
Metastatic complications are responsible for more than 90% of cancer related deaths. The progression from an isolated tumor to disseminated metastatic disease is a multi-step process, with each step involving intricate cross-talk between the cancer cells and their non-cellular surroundings, the extracellular matrix (ECM). Many ECM proteins are significantly de-regulated during the progression of cancer, causing both biochemical and biomechanical changes that together promote the metastatic ca...
Minimal Realizations of Supersymmetry for Matrix Hamiltonians
Andrianov, Alexandr A
2014-01-01
The notions of weak and strong minimizability of a matrix intertwining operator are introduced. Criterion of strong minimizability of a matrix intertwining operator is revealed. Criterion and sufficient condition of existence of a constant symmetry matrix for a matrix Hamiltonian are presented. A method of constructing of a matrix Hamiltonian with a given constant symmetry matrix in terms of a set of arbitrary scalar functions and eigen- and associated vectors of this matrix is offered. Examples of constructing of $2\\times2$ matrix Hamiltonians with given symmetry matrices for the cases of different structure of Jordan form of these matrices are elucidated.
Sparse Planar Array Synthesis Using Matrix Enhancement and Matrix Pencil
Directory of Open Access Journals (Sweden)
Mei-yan Zheng
2013-01-01
Full Text Available The matrix enhancement and matrix pencil (MEMP plays important roles in modern signal processing applications. In this paper, MEMP is applied to attack the problem of two-dimensional sparse array synthesis. Firstly, the desired array radiation pattern, as the original pattern for approximating, is sampled to form an enhanced matrix. After performing the singular value decomposition (SVD and discarding the insignificant singular values according to the prior approximate error, the minimum number of elements can be obtained. Secondly, in order to obtain the eigenvalues, the generalized eigen-decomposition is employed on the approximate matrix, which is the optimal low-rank approximation of the enhanced matrix corresponding to sparse planar array, and then the ESPRIT algorithm is utilized to pair the eigenvalues related to each dimension of the planar array. Finally, element positions and excitations of the sparse planar array are calculated according to the correct pairing of eigenvalues. Simulation results are presented to illustrate the effectiveness of the proposed approach.
The Astrobiology Matrix and the "Drake Matrix" in Education
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.
A survey of matrix theory and matrix inequalities
Marcus, Marvin
2010-01-01
Written for advanced undergraduate students, this highly regarded book presents an enormous amount of information in a concise and accessible format. Beginning with the assumption that the reader has never seen a matrix before, the authors go on to provide a survey of a substantial part of the field, including many areas of modern research interest.Part One of the book covers not only the standard ideas of matrix theory, but ones, as the authors state, ""that reflect our own prejudices,"" among them Kronecker products, compound and induced matrices, quadratic relations, permanents, incidence
Matrix factorizations and elliptic fibrations
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.
Octonionic matrix representation and electromagnetism
Energy Technology Data Exchange (ETDEWEB)
Chanyal, B. C. [Kumaun University, S. S. J. Campus, Almora (India)
2014-12-15
Keeping in mind the important role of octonion algebra, we have obtained the electromagnetic field equations of dyons with an octonionic 8 x 8 matrix representation. In this paper, we consider the eight - dimensional octonionic space as a combination of two (external and internal) four-dimensional spaces for the existence of magnetic monopoles (dyons) in a higher-dimensional formalism. As such, we describe the octonion wave equations in terms of eight components from the 8 x 8 matrix representation. The octonion forms of the generalized potential, fields and current source of dyons in terms of 8 x 8 matrix are discussed in a consistent manner. Thus, we have obtained the generalized Dirac-Maxwell equations of dyons from an 8x8 matrix representation of the octonion wave equations in a compact and consistent manner. The generalized Dirac-Maxwell equations are fully symmetric Maxwell equations and allow for the possibility of magnetic charges and currents, analogous to electric charges and currents. Accordingly, we have obtained the octonionic Dirac wave equations in an external field from the matrix representation of the octonion-valued potentials of dyons.
Matrix factorizations and elliptic fibrations
Directory of Open Access Journals (Sweden)
Harun Omer
2016-09-01
Full Text Available 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.
Cellular Traction Stresses Mediate Extracellular Matrix Degradation by Invadopodia
Jerrell, Rachel J.; Parekh, Aron
2014-01-01
During tumorigenesis, matrix rigidity can drive oncogenic transformation via altered cellular proliferation and migration. Cells sense extracellular matrix (ECM) mechanical properties with intracellular tensile forces generated by actomyosin contractility. These contractile forces are transmitted to the matrix surface as traction stresses which mediate mechanical interactions with the ECM. Matrix rigidity has been shown to increase proteolytic ECM degradation by cytoskeletal structures known as invadopodia that are critical for cancer progression suggesting that cellular contractility promotes invasive behavior. However, both increases and decreases in traction stresses have been associated with metastatic behavior. Therefore, the role of cellular contractility in invasive migration leading to metastasis is unclear. To determine the relationship between cellular traction stresses and invadopodia activity, we characterized the invasive and contractile properties of an aggressive carcinoma cell line utilizing polyacrylamide gels of different rigidities. We found that ECM degradation and traction stresses were linear functions of matrix rigidity. Using calyculin A to augment myosin contractility, we also found that traction stresses were strongly predictive of ECM degradation. Overall, our data suggest that cellular force generation may play an important part in invasion and metastasis by mediating invadopodia activity in response to the mechanical properties of the tumor microenvironment. PMID:24412623
Factors Involved in Extracellular Matrix Turnover in Human Derived Cardiomyocytes
Directory of Open Access Journals (Sweden)
Gregori Casals
2013-11-01
Full Text Available Background: The molecular mechanisms by which myocardial ischemia translates into ventricular remodeling remain unclear. Methods: We investigated whether hypoxia and proinflammatory cytokines are specific inducers of remodeling signals in an in vitro model of cultured adult human ventricular myocytes (AC16 cells. Results:Hypoxia modified the ratio of matrix remodeling factors by increasing the aminoterminal propeptide of type III procollagen (PIIINP and reducing tissue inhibitor of matrix metalloproteinase type 1 (TIMP-1 secretion in AC16 cells. These effects, however, were not associated with either modifications in expression of matrix metalloproteinase type 2, collagen-I or metalloproteinase activity. Hypoxia does, actually increase the production of the cardiac antifibrogenic growth factors, Apelin and VEGF, through an Hypoxia Inducible Factor type 1-dependent mechanism. Concerning proinflammatory signaling pathways, IL1β emerged as a powerful inducer of matrix turnover, since it significantly enhanced PIIINP, TIMP-1 and hyaluronic acid production and increased metalloproteinase activity. In contrast, TNFα did not modify matrix turnover but markedly induced the production of Apelin and VEGF. Conclusion: Hypoxia and increased TNFα activity likely exert cardioprotective actions by activating the cardiac antifibrogenic factors Apelin and VEGF. In contrast, IL1β is a strong promoter of interstitial collagen remodeling that may contribute to ventricular dilation and heart failure in the ischemic myocardium.
Dijkgraaf, R; Dijkgraaf, Robbert; Vafa, Cumrun
2002-01-01
We point out two extensions of the relation between matrix models, topological strings and N=1 supersymmetric gauge theories. First, we note that by considering double scaling limits of unitary matrix models one can obtain large N duals of the local Calabi-Yau geometries that engineer N=2 gauge theories. In particular, a double scaling limit of the Gross-Witten one-plaquette lattice model gives the SU(2) Seiberg-Witten solution, including its induced gravitational corrections. Secondly, we point out that the effective superpotential terms for N=1 ADE quiver gauge theories is similarly computed by large multi-matrix models, that have been considered in the context of ADE minimal models on random surfaces. The associated spectral curves are multiple branched covers obtained as Virasoro and W-constraints of the partition function.
Dijkgraaf, Robbert; Vafa, Cumrun
2002-11-01
We point out two extensions of the relation between matrix models, topological strings and N=1 supersymmetric gauge theories. First, we note that by considering double scaling limits of unitary matrix models one can obtain large- N duals of the local Calabi-Yau geometries that engineer N=2 gauge theories. In particular, a double scaling limit of the Gross-Witten one-plaquette lattice model gives the SU(2) Seiberg-Witten solution, including its induced gravitational corrections. Secondly, we point out that the effective superpotential terms for N=1 ADE quiver gauge theories is similarly computed by large- N multi-matrix models, that have been considered in the context of ADE minimal models on random surfaces. The associated spectral curves are multiple branched covers obtained as Virasoro and W-constraints of the partition function.
Energy Technology Data Exchange (ETDEWEB)
Dijkgraaf, Robbert E-mail: rhd@science.uva.nl; Vafa, Cumrun
2002-11-11
We point out two extensions of the relation between matrix models, topological strings and N=1 supersymmetric gauge theories. First, we note that by considering double scaling limits of unitary matrix models one can obtain large-N duals of the local Calabi-Yau geometries that engineer N=2 gauge theories. In particular, a double scaling limit of the Gross-Witten one-plaquette lattice model gives the SU(2) Seiberg-Witten solution, including its induced gravitational corrections. Secondly, we point out that the effective superpotential terms for N=1 ADE quiver gauge theories is similarly computed by large-N multi-matrix models, that have been considered in the context of ADE minimal models on random surfaces. The associated spectral curves are multiple branched covers obtained as Virasoro and W-constraints of the partition function.
Lectures on matrix field theory
Ydri, Badis
2017-01-01
These lecture notes provide a systematic introduction to matrix models of quantum field theories with non-commutative and fuzzy geometries. The book initially focuses on the matrix formulation of non-commutative and fuzzy spaces, followed by a description of the non-perturbative treatment of the corresponding field theories. As an example, the phase structure of non-commutative phi-four theory is treated in great detail, with a separate chapter on the multitrace approach. The last chapter offers a general introduction to non-commutative gauge theories, while two appendices round out the text. Primarily written as a self-study guide for postgraduate students – with the aim of pedagogically introducing them to key analytical and numerical tools, as well as useful physical models in applications – these lecture notes will also benefit experienced researchers by providing a reference guide to the fundamentals of non-commutative field theory with an emphasis on matrix models and fuzzy geometries.
Noncommutative spaces from matrix models
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
Mitochondrial unfolded protein response controls matrix pre-RNA processing and translation.
Münch, Christian; Harper, J Wade
2016-06-30
The mitochondrial matrix is unique in that it must integrate the folding and assembly of proteins derived from the nuclear and mitochondrial genomes. In Caenorhabditis elegans, the mitochondrial unfolded protein response (UPRmt) senses matrix protein misfolding and induces a program of nuclear gene expression, including mitochondrial chaperonins, to promote mitochondrial proteostasis. While misfolded mitochondrial-matrix-localized ornithine transcarbamylase induces chaperonin expression, our understanding of mammalian UPRmt is rudimentary, reflecting a lack of acute triggers for UPRmt activation. This limitation has prevented analysis of the cellular responses to matrix protein misfolding and the effects of UPRmt on mitochondrial translation to control protein folding loads. Here we combine pharmacological inhibitors of matrix-localized HSP90/TRAP1 (ref. 8) or LON protease, which promote chaperonin expression, with global transcriptional and proteomic analysis to reveal an extensive and acute response of human cells to UPRmt. This response encompasses widespread induction of nuclear genes, including matrix-localized proteins involved in folding, pre-RNA processing and translation. Functional studies revealed rapid but reversible translation inhibition in mitochondria occurring concurrently with defects in pre-RNA processing caused by transcriptional repression and LON-dependent turnover of the mitochondrial pre-RNA processing nuclease MRPP3 (ref. 10). This study reveals that acute mitochondrial protein folding stress activates both increased chaperone availability within the matrix and reduced matrix-localized protein synthesis through translational inhibition, and provides a framework for further dissection of mammalian UPRmt.
Supersymmetry in random matrix theory
Energy Technology Data Exchange (ETDEWEB)
Kieburg, Mario
2010-05-04
I study the applications of supersymmetry in random matrix theory. I generalize the supersymmetry method and develop three new approaches to calculate eigenvalue correlation functions. These correlation functions are averages over ratios of characteristic polynomials. In the first part of this thesis, I derive a relation between integrals over anti-commuting variables (Grassmann variables) and differential operators with respect to commuting variables. With this relation I rederive Cauchy- like integral theorems. As a new application I trace the supermatrix Bessel function back to a product of two ordinary matrix Bessel functions. In the second part, I apply the generalized Hubbard-Stratonovich transformation to arbitrary rotation invariant ensembles of real symmetric and Hermitian self-dual matrices. This extends the approach for unitarily rotation invariant matrix ensembles. For the k-point correlation functions I derive supersymmetric integral expressions in a unifying way. I prove the equivalence between the generalized Hubbard-Stratonovich transformation and the superbosonization formula. Moreover, I develop an alternative mapping from ordinary space to superspace. After comparing the results of this approach with the other two supersymmetry methods, I obtain explicit functional expressions for the probability densities in superspace. If the probability density of the matrix ensemble factorizes, then the generating functions exhibit determinantal and Pfaffian structures. For some matrix ensembles this was already shown with help of other approaches. I show that these structures appear by a purely algebraic manipulation. In this new approach I use structures naturally appearing in superspace. I derive determinantal and Pfaffian structures for three types of integrals without actually mapping onto superspace. These three types of integrals are quite general and, thus, they are applicable to a broad class of matrix ensembles. (orig.)
Polychoric/Tetrachoric Matrix or Pearson Matrix? A methodological study
Directory of Open Access Journals (Sweden)
Dominguez Lara, Sergio Alexis
2014-04-01
Full Text Available The use of product-moment correlation of Pearson is common in most studies in factor analysis in psychology, but it is known that this statistic is only applicable when the variables related are in interval scale and normally distributed, and when are used in ordinal data may to produce a distorted correlation matrix . Thus is a suitable option using polychoric/tetrachoric matrices in item-level factor analysis when the items are in level measurement nominal or ordinal. The aim of this study was to show the differences in the KMO, Bartlett`s Test and Determinant of the Matrix, percentage of variance explained and factor loadings in depression trait scale of Depression Inventory Trait - State and the Neuroticism dimension of the short form of the Eysenck Personality Questionnaire -Revised, regarding the use of matrices polychoric/tetrachoric matrices and Pearson. These instruments was analyzed with different extraction methods (Maximum Likelihood, Minimum Rank Factor Analysis, Unweighted Least Squares and Principal Components, keeping constant the rotation method Promin were analyzed. Were observed differences regarding sample adequacy measures, as well as with respect to the explained variance and the factor loadings, for solutions having as polychoric/tetrachoric matrix. So it can be concluded that the polychoric / tetrachoric matrix give better results than Pearson matrices when it comes to item-level factor analysis using different methods.
Symmetries and Interactions in Matrix String Theory
Hacquebord, F.H.
1999-01-01
This PhD-thesis reviews matrix string theory and recent developments therein. The emphasis is put on symmetries, interactions and scattering processes in the matrix model. We start with an introduction to matrix string theory and a review of the orbifold model that flows out of matrix string theory
Minimal realizations of supersymmetry for matrix Hamiltonians
Energy Technology Data Exchange (ETDEWEB)
Andrianov, Alexander A., E-mail: andrianov@icc.ub.edu; Sokolov, Andrey V., E-mail: avs_avs@rambler.ru
2015-02-06
The notions of weak and strong minimizability of a matrix intertwining operator are introduced. Criterion of strong minimizability of a matrix intertwining operator is revealed. Criterion and sufficient condition of existence of a constant symmetry matrix for a matrix Hamiltonian are presented. A method of constructing of a matrix Hamiltonian with a given constant symmetry matrix in terms of a set of arbitrary scalar functions and eigen- and associated vectors of this matrix is offered. Examples of constructing of 2×2 matrix Hamiltonians with given symmetry matrices for the cases of different structure of Jordan form of these matrices are elucidated. - Highlights: • Weak and strong minimization of a matrix intertwining operator. • Criterion of strong minimizability from the right of a matrix intertwining operator. • Conditions of existence of a constant symmetry matrix for a matrix Hamiltonian. • Method of constructing of a matrix Hamiltonian with a given constant symmetry matrix. • Examples of constructing of 2×2 matrix Hamiltonians with a given symmetry matrix.
Steerneman, A.G.M.; van Perlo -ten Kleij, Frederieke
2005-01-01
The main topic of this paper is the matrix V = A - XY*, where A is a nonsingular complex k x k matrix and X and Y are k x p complex matrices of full column rank. Because properties of the matrix V can be derived from those of the matrix Q = I - XY*, we will consider in particular the case where A =
Symmetries and Interactions in Matrix String Theory
Hacquebord, F.H.
1999-01-01
This PhD-thesis reviews matrix string theory and recent developments therein. The emphasis is put on symmetries, interactions and scattering processes in the matrix model. We start with an introduction to matrix string theory and a review of the orbifold model that flows out of matrix string theory
Towards Google matrix of brain
Energy Technology Data Exchange (ETDEWEB)
Shepelyansky, D.L., E-mail: dima@irsamc.ups-tlse.f [Laboratoire de Physique Theorique (IRSAMC), Universite de Toulouse, UPS, F-31062 Toulouse (France); LPT - IRSAMC, CNRS, F-31062 Toulouse (France); Zhirov, O.V. [Budker Institute of Nuclear Physics, 630090 Novosibirsk (Russian Federation)
2010-07-12
We apply the approach of the Google matrix, used in computer science and World Wide Web, to description of properties of neuronal networks. The Google matrix G is constructed on the basis of neuronal network of a brain model discussed in PNAS 105 (2008) 3593. We show that the spectrum of eigenvalues of G has a gapless structure with long living relaxation modes. The PageRank of the network becomes delocalized for certain values of the Google damping factor {alpha}. The properties of other eigenstates are also analyzed. We discuss further parallels and similarities between the World Wide Web and neuronal networks.
Random matrix theory and multivariate statistics
Diaz-Garcia, Jose A.; Jáimez, Ramon Gutiérrez
2009-01-01
Some tools and ideas are interchanged between random matrix theory and multivariate statistics. In the context of the random matrix theory, classes of spherical and generalised Wishart random matrix ensemble, containing as particular cases the classical random matrix ensembles, are proposed. Some properties of these classes of ensemble are analysed. In addition, the random matrix ensemble approach is extended and a unified theory proposed for the study of distributions for real normed divisio...
Matrix theory selected topics and useful results
Mehta, Madan Lal
1989-01-01
Matrices and operations on matrices ; determinants ; elementary operations on matrices (continued) ; eigenvalues and eigenvectors, diagonalization of normal matrices ; functions of a matrix ; positive definiteness, various polar forms of a matrix ; special matrices ; matrices with quaternion elements ; inequalities ; generalised inverse of a matrix ; domain of values of a matrix, location and dispersion of eigenvalues ; symmetric functions ; integration over matrix variables ; permanents of doubly stochastic matrices ; infinite matrices ; Alexander matrices, knot polynomials, torsion numbers.
Sign Patterns That Allow the Given Matrix
Institute of Scientific and Technical Information of China (English)
邵燕灵; 孙良
2003-01-01
Let P be a property referring to a real matrix. For a sign pattern A, if there exists a real matrix B in the qualitative class of A such that B has property P, then we say A allows P. Three cases that A allows an M-matrix, an inverse M-matrix and a P0-matrix are considered. The complete characterizations are obtained.
Unravelling the nuclear matrix proteome
DEFF Research Database (Denmark)
Albrethsen, Jakob; Knol, Jaco C; Jimenez, Connie R
2009-01-01
The nuclear matrix (NM) model posits the presence of a protein/RNA scaffold that spans the mammalian nucleus. The NM proteins are involved in basic nuclear function and are a promising source of protein biomarkers for cancer. Importantly, the NM proteome is operationally defined as the proteins...
Parallel Sparse Matrix - Vector Product
DEFF Research Database (Denmark)
Alexandersen, Joe; Lazarov, Boyan Stefanov; Dammann, Bernd
This technical report contains a case study of a sparse matrix-vector product routine, implemented for parallel execution on a compute cluster with both pure MPI and hybrid MPI-OpenMP solutions. C++ classes for sparse data types were developed and the report shows how these class can be used...
Matrix Treatment of Ray Optics.
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…
Sparse Matrix Vector Processing Formats
Stathis, P.T.
2004-01-01
In this dissertation we have identified vector processing shortcomings related to the efficient storing and processing of sparse matrices. To alleviate existent problems we propose two storage formats denoted as Block Based Compression Storage (BBCS) format and Hierarchical Sparse Matrix (HiSM) stor
The COMPADRE Plant Matrix Database
DEFF Research Database (Denmark)
2014-01-01
COMPADRE contains demographic information on hundreds of plant species. The data in COMPADRE are in the form of matrix population models and our goal is to make these publicly available to facilitate their use for research and teaching purposes. COMPADRE is an open-access database. We only request...
Hyper-systolic matrix multiplication
Lippert, Th.; Petkov, N.; Palazzari, P.; Schilling, K.
2001-01-01
A novel parallel algorithm for matrix multiplication is presented. It is based on a 1-D hyper-systolic processor abstraction. The procedure can be implemented on all types of parallel systems. (C) 2001 Elsevier Science B,V. All rights reserved.
Student Transfer Matrix, Fall 1996.
Oklahoma State Regents for Higher Education, Oklahoma City.
The Student Transfer Matrix provides data on the numbers of students transferring from Oklahoma public and private institutions of higher education to other Oklahoma institutions, using data from receiving institutions. Among the highlights are: the number of students who transferred to four-year and two-year institutions remained steady at 57.8…
Regularization in Matrix Relevance Learning
Schneider, Petra; Bunte, Kerstin; Stiekema, Han; Hammer, Barbara; Villmann, Thomas; Biehl, Michael
2010-01-01
A In this paper, we present a regularization technique to extend recently proposed matrix learning schemes in learning vector quantization (LVQ). These learning algorithms extend the concept of adaptive distance measures in LVQ to the use of relevance matrices. In general, metric learning can displa
Perturbation semigroup of matrix algebras
Neumann, N.; Suijlekom, W.D. van
2016-01-01
In this article we analyze the structure of the semigroup of inner perturbations in noncommutative geometry. This perturbation semigroup is associated to a unital associative *-algebra and extends the group of unitary elements of this *-algebra. We compute the perturbation semigroup for all matrix algebras.
Bilateral matrix-exponential distributions
DEFF Research Database (Denmark)
Bladt, Mogens; Esparza, Luz Judith R; Nielsen, Bo Friis
2012-01-01
In this article we define the classes of bilateral and multivariate bilateral matrix-exponential distributions. These distributions have support on the entire real space and have rational moment-generating functions. These distributions extend the class of bilateral phasetype distributions of [1]...
Multivariate Modelling via Matrix Subordination
DEFF Research Database (Denmark)
Nicolato, Elisa
stochastic volatility via time-change is quite ineffective when applied to the multivariate setting. In this work we propose a new class of models, which is obtained by conditioning a multivariate Brownian Motion to a so-called matrix subordinator. The obtained model-class encompasses the vast majority...
Neonatal disorders of germinal matrix
Raets, M M A; Dudink, J; Govaert, P
2015-01-01
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 haemorrhag
Adams Operations on Matrix Factorizations
Brown, Michael K.; Miller, Claudia; Thompson, Peder; Walker, Mark E.
2016-01-01
We define Adams operations on matrix factorizations, and we show these operations enjoy analogues of several key properties of the Adams operations on perfect complexes with support developed by Gillet-Soul\\'e in their paper "Intersection Theory Using Adams Operations". As an application, we give a proof of a conjecture of Dao-Kurano concerning the vanishing of Hochster's theta invariant.
Parallel Sparse Matrix - Vector Product
DEFF Research Database (Denmark)
Alexandersen, Joe; Lazarov, Boyan Stefanov; Dammann, Bernd
This technical report contains a case study of a sparse matrix-vector product routine, implemented for parallel execution on a compute cluster with both pure MPI and hybrid MPI-OpenMP solutions. C++ classes for sparse data types were developed and the report shows how these class can be used...
The COMPADRE Plant Matrix Database
DEFF Research Database (Denmark)
2014-01-01
COMPADRE contains demographic information on hundreds of plant species. The data in COMPADRE are in the form of matrix population models and our goal is to make these publicly available to facilitate their use for research and teaching purposes. COMPADRE is an open-access database. We only request...
Multivariate Matrix-Exponential Distributions
DEFF Research Database (Denmark)
Bladt, Mogens; Nielsen, Bo Friis
2010-01-01
-exponential distributions. We prove a characterization that states that a distribution is an MVME distribution if and only if all non-negative, non-null linear combinations of the coordinates have a univariate matrix-exponential distribution. This theorem is analog to a well-known characterization theorem...
Mason, A. J.
Multichannel sound systems are being studied as part of the Eureka 95 and Radio-communication Bureau TG10-1 investigations into high definition television. One emerging sound system has five channels; three at the front and two at the back. This raises some compatibility issues. The listener might have only, say, two loudspeakers or the material to be broadcast may have fewer than five channels. The problem is how best to produce a set of signals to be broadcast, which is suitable for all listeners, from those that are available. To investigate this area, a device has been designed and built which has six input channels and six output channels. Each output signal is a linear combination of the input signals. The inputs and outputs are in AES/EBU digital audio format using BBC-designed AESIC chips. The matrix operation, to produce the six outputs from the six inputs, is performed by a Motorola DSP56001. The user interface and 'housekeeping' is managed by a T222 transputer. The operator of the matrix uses a VDU to enter sets of coefficients and a rotary switch to select which set to use. A set of analog controls is also available and is used to control operations other than the simple compatibility matrixing. The matrix has been very useful for simple tasks: mixing a stereo signal into mono, creating a stereo signal from a mono signal, applying a fixed gain or attenuation to a signal, exchanging the A and B channels of an AES/EBU bitstream, and so on. These are readily achieved using simple sets of coefficients. Additions to the user interface software have led to several more sophisticated applications which still consist of a matrix operation. Different multichannel panning laws have been evaluated. The analog controls adjust the panning; the audio signals are processed digitally using a matrix operation. A digital SoundField microphone decoder has also been implemented. digital audio matrix is such that it can be applied to a wide variety of signal processing
RICE SUCROSE SYNTHASE PROMOTER
DEFF Research Database (Denmark)
2000-01-01
A promoter is described. The promoter comprises a nucleotide sequence corresponding to that shown as SEQ ID No. 1 or a variant, homologue or derivative thereof.......A promoter is described. The promoter comprises a nucleotide sequence corresponding to that shown as SEQ ID No. 1 or a variant, homologue or derivative thereof....
A DIRECT ALGORITHM FOR DISTINGUISHING NONSINGULAR M-MATRIX AND H-MATRIX
Institute of Scientific and Technical Information of China (English)
Li Yaotang; Zhu Yan
2005-01-01
A direct algorithm is proposed by which one can distinguish whether a matrix is an M-matrix (or H-matrix) or not quickly and effectively. Numerical examples show that it is effective and convincible to distinguish M-matrix (or H-matrix) by using the algorithm.
Eukaryotic Promoter Recognition Using Back propagation Neural Network
Institute of Scientific and Technical Information of China (English)
XIONGQing; WANGYuan-Qiang; LIZhi-Liang
2004-01-01
A new system is developed to recognize promoter sequences from non-promoter sequences based on position weight matrix and backpropagation neural network in this paper. The system performs significantly better on the training set and the test set, the mean recognition rate is as high as 99% on the training set and 97% on the testing set. Experimental results demonstrate the effectiveness of the system to recognize the promoter sequences that have been trained and the promoter sequences that have not been seen previously.
Institute of Scientific and Technical Information of China (English)
钟小明; 胡侦明; 沈皆亮; 王大武; 甘强; 郝杰
2012-01-01
Objective To explore the effect and mechanism of resveratrol on extracellular matrix synthesize in degenerative disc endplate cartilage cells. Methods Degenerative disc endplate chondrocytes( DECs) ,derived from elder patient with lumbar disc hernia, were randomly divided into resveratrol (Res) , dimethyl sulfoxide ( DMSO) control, resveratrol + nicotinamide ( Nam) , resveratrol + siRNA and control groups. DECs were stimulated with corresponding reagent for 48 h. The Expression of SIRT1, type Ⅱ collagen, aggrecan and SIRT1 mRNA were detected,as well as enzymatic activity of SIRT1. Result Results 100 μmol/L Res intervention increased the expression of both SIRT1 and SIRT1 mRNA, enzymatic activity of SIRT1, thus stimulating synthesis of extracellular matrix . Nam and siRNA intervention effectively supressed SIRT1 enzymatic activity and SIRT1 mRNA expression respectively, thus inhibited synthesis of extracellular matrix. Conclusions Res intervention could stimulate DECs to synthesize of extracellular matrix, thus inhibit cartilage endplate degeneration. This may take effect by activating SIRT1.%目的 探讨白藜芦醉(Res)干预对退变椎间盘终板软骨细胞(DEC)合成细胞外基质的影响.方法 老年腰椎间盘突出症患者的终板软骨细胞培养、传代,P2代细胞随机分为5组,即Res组、二甲基亚砜对照组、Res+尼克酰胺(Nam)组、Res+ siRNA转染组及空白对照组.各组进行对应处理后检测沉默信息调节因子2相关酶1( SIRT1)、Ⅱ型胶原(COLA2)、蛋白聚糖聚合物(agg recan)及SIRT1 mRNA表达水平.结果 Res干预上调DEC SIRT1 mRNA及蛋白的表达,促进细胞外基质(COLA2,aggrecan)的合成；Nam及siRNA干预分别有效抑制了SIRT1酶括性及SIRT1 mRNA的表达,并抑制了细胞外基质的合成.结论 Res可促进DEC合成细胞外基质,抑制椎间盘软骨终板退变,其机制与调节SIRT1活性有关.
Scanning Electron Microscopy of Macerated Tissue to Visualize the Extracellular Matrix.
Stephenson, Matthew K; Lenihan, Sean; Covarrubias, Roman; Huttinger, Ryan M; Gumina, Richard J; Sawyer, Douglas B; Galindo, Cristi L
2016-06-14
Fibrosis is a component of all forms of heart disease regardless of etiology, and while much progress has been made in the field of cardiac matrix biology, there are still major gaps related to how the matrix is formed, how physiological and pathological remodeling differ, and most importantly how matrix dynamics might be manipulated to promote healing and inhibit fibrosis. There is currently no treatment option for controlling, preventing, or reversing cardiac fibrosis. Part of the reason is likely the sheer complexity of cardiac scar formation, such as occurs after myocardial infarction to immediately replace dead or dying cardiomyocytes. The extracellular matrix itself participates in remodeling by activating resident cells and also by helping to guide infiltrating cells to the defunct lesion. The matrix is also a storage locker of sorts for matricellular proteins that are crucial to normal matrix turnover, as well as fibrotic signaling. The matrix has additionally been demonstrated to play an electromechanical role in cardiac tissue. Most techniques for assessing fibrosis are not qualitative in nature, but rather provide quantitative results that are useful for comparing two groups but that do not provide information related to the underlying matrix structure. Highlighted here is a technique for visualizing cardiac matrix ultrastructure. Scanning electron microscopy of decellularized heart tissue reveals striking differences in structure that might otherwise be missed using traditional quantitative research methods.
Matrix stiffness reverses the effect of actomyosin tension on cell proliferation
Mih, Justin D.; Marinkovic, Aleksandar; Liu, Fei; Sharif, Asma S.; Tschumperlin, Daniel J.
2012-01-01
Summary The stiffness of the extracellular matrix exerts powerful effects on cell proliferation and differentiation, but the mechanisms transducing matrix stiffness into cellular fate decisions remain poorly understood. Two widely reported responses to matrix stiffening are increases in actomyosin contractility and cell proliferation. To delineate their relationship, we modulated cytoskeletal tension in cells grown across a physiological range of matrix stiffnesses. On both synthetic and naturally derived soft matrices, and across a panel of cell types, we observed a striking reversal of the effect of inhibiting actomyosin contractility, switching from the attenuation of proliferation on rigid substrates to the robust promotion of proliferation on soft matrices. Inhibiting contractility on soft matrices decoupled proliferation from cytoskeletal tension and focal adhesion organization, but not from cell spread area. Our results demonstrate that matrix stiffness and actomyosin contractility converge on cell spreading in an unexpected fashion to control a key aspect of cell fate. PMID:23097048
New Construction Approach of Basic Belief Assignment Function Based on Confusion Matrix
Directory of Open Access Journals (Sweden)
Jing Zhu
2012-08-01
Full Text Available In the application of belief function theory, the first problem is the construction of the basic belief assignment. This study presents a new construction approach based on the confusion matrix. The method starts from the output of the confusion matrix and then designs construction strategy for basic belief assignment functions based on the expectation vector of the confusion matrix. Comparative tests of several other construction methods on the U.C.I database show that our proposed method can achieve higher target classification accuracy, lower computational complexity, which has a strong ability to promote the application.
The Constrained Solutions of Two Matrix Equations
Institute of Scientific and Technical Information of China (English)
An Ping LIAO; Zhong Zhi BAI
2002-01-01
We study the symmetric positive semidefinite solution of the matrix equation AX1AT +BX2BT = C, where A is a given real m × n matrix, B is a given real m × p matrix, and C is a givenreal m × m matrix, with m, n, p positive integers; and the bisymmetric positive semidefinite solutionof the matrix equation DTXD = C, where D is a given real n × m matrix, C is a given real m × mmatrix, with m, n positive integers. By making use of the generalized singular value decomposition, wederive general analytic formulae, and present necessary and sufficient conditions for guaranteeing theexistence of these solutions.
Scrambling with matrix black holes
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.
Link Prediction via Matrix Completion
Pech, Ratha; Pan, Liming; Cheng, Hong; Zhou, Tao
2016-01-01
Inspired by practical importance of social networks, economic networks, biological networks and so on, studies on large and complex networks have attracted a surge of attentions 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 one hand, our algorithm is based on the sparsity and low rank property of the matrix, 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, whatever it is weighted or unweighted, our method is demonstrated to be very effective and with prediction accuracy being considerably improved comparing wit...
Standardisation of ceramic matrix composites
Directory of Open Access Journals (Sweden)
Gomez Philippe
2015-01-01
Full Text Available The standardisation on ceramic matrix composite (CMCs test methods occurred in the 1980's as these materials began to display interesting properties for aeronautical applications. Since the French Office of standardisation B43C has participated in establishing more than 40 standards and guides dealing with their thermal mechanical properties, their reinforcement and their fibre/matrix interface. As their maturity has been demonstrated through several technological development programmes (plugs, flaps, blades …, the air framers and engine manufacturers are now thinking of develop industrial parts which require a certification from airworthiness authorities. Now the standardisation of CMCs has to turn toward documents completing the certification requirement for civil and military applications. The news standards will allow being more confident with CMCs in taking into account their specificity.
Density matrix quantum Monte Carlo
Blunt, N S; Spencer, J S; Foulkes, W M C
2013-01-01
This paper describes a quantum Monte Carlo method capable of sampling the full density matrix of a many-particle system, thus granting access to arbitrary reduced density matrices and allowing expectation values of complicated non-local operators to be evaluated easily. The direct sampling of the density matrix also raises the possibility of calculating previously inaccessible entanglement measures. The algorithm closely resembles the recently introduced full configuration interaction quantum Monte Carlo method, but works all the way from infinite to zero temperature. We explain the theory underlying the method, describe the algorithm, and introduce an importance-sampling procedure to improve the stochastic efficiency. To demonstrate the potential of our approach, the energy and staggered magnetization of the isotropic antiferromagnetic Heisenberg model on small lattices and the concurrence of one-dimensional spin rings are compared to exact or well-established results. Finally, the nature of the sign problem...
Matrix dynamics of fuzzy spheres
Jatkar, D P; Wadia, S R; Yogendran, K P; Jatkar, Dileep P.; Mandal, Gautam; Wadia, Spenta R.
2002-01-01
We study the dynamics of fuzzy two-spheres in a matrix model which represents string theory in the presence of RR flux. We analyze the stability of known static solutions of such a theory which contain commuting matrices and SU(2) representations. We find that irreducible as well as reducible representations are stable. Since the latter are of higher energy, this stability poses a puzzle. We resolve this puzzle by noting that reducible representations have marginal directions corresponding to non-spherical deformations. We obtain new static solutions by turning on these marginal deformations. These solutions now have instability or tachyonic directions. We discuss condensation of these tachyons which correspond to classical trajectories interpolating from multiple, small fuzzy spheres to a single, large sphere. We briefly discuss spatially independent configurations of a D3/D5 system described by the same matrix model which now possesses a supergravity dual.
Matrix metalloproteinases in lung biology
Directory of Open Access Journals (Sweden)
Parks William C
2000-12-01
Full Text Available Abstract Despite much information on their catalytic properties and gene regulation, we actually know very little of what matrix metalloproteinases (MMPs do in tissues. The catalytic activity of these enzymes has been implicated to function in normal lung biology by participating in branching morphogenesis, homeostasis, and repair, among other events. Overexpression of MMPs, however, has also been blamed for much of the tissue destruction associated with lung inflammation and disease. Beyond their role in the turnover and degradation of extracellular matrix proteins, MMPs also process, activate, and deactivate a variety of soluble factors, and seldom is it readily apparent by presence alone if a specific proteinase in an inflammatory setting is contributing to a reparative or disease process. An important goal of MMP research will be to identify the actual substrates upon which specific enzymes act. This information, in turn, will lead to a clearer understanding of how these extracellular proteinases function in lung development, repair, and disease.
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.
Matrix Factorization for Evolution Data
Directory of Open Access Journals (Sweden)
Xiao-Yu Huang
2014-01-01
Full Text Available We study a matrix factorization problem, that is, to find two factor matrices U and V such that R≈UT×V, where R is a matrix composed of the values of the objects O1,O2,…,On at consecutive time points T1,T2,…,Tt. We first present MAFED, a constrained optimization model for this problem, which straightforwardly performs factorization on R. Then based on the interplay of the data in U, V, and R, a probabilistic graphical model using the same optimization objects is constructed, in which structural dependencies of the data in these matrices are revealed. Finally, we present a fitting algorithm to solve the proposed MAFED model, which produces the desired factorization. Empirical studies on real-world datasets demonstrate that our approach outperforms the state-of-the-art comparison algorithms.
Immunomodulatory effects of amniotic membrane matrix incorporated into collagen scaffolds.
Hortensius, Rebecca A; Ebens, Jill H; Harley, Brendan A C
2016-06-01
Adult tendon wound repair is characterized by the formation of disorganized collagen matrix which leads to decreases in mechanical properties and scar formation. Studies have linked this scar formation to the inflammatory phase of wound healing. Instructive biomaterials designed for tendon regeneration are often designed to provide both structural and cellular support. In order to facilitate regeneration, success may be found by tempering the body's inflammatory response. This work combines collagen-glycosaminoglycan scaffolds, previously developed for tissue regeneration, with matrix materials (hyaluronic acid and amniotic membrane) that have been shown to promote healing and decreased scar formation in skin studies. The results presented show that scaffolds containing amniotic membrane matrix have significantly increased mechanical properties and that tendon cells within these scaffolds have increased metabolic activity even when the media is supplemented with the pro-inflammatory cytokine interleukin-1 beta. Collagen scaffolds containing hyaluronic acid or amniotic membrane also temper the expression of genes associated with the inflammatory response in normal tendon healing (TNF-α, COLI, MMP-3). These results suggest that alterations to scaffold composition, to include matrix known to decrease scar formation in vivo, can modify the inflammatory response in tenocytes. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1332-1342, 2016.
The Role of Matrix Metalloproteinases in Renal Diseases
Directory of Open Access Journals (Sweden)
Funda SAĞLAM
2011-05-01
Full Text Available Matrix metalloproteinases (MMPs are a family of zinc dependent proteinases and the main promoters of extracellular matrix degradation. Their role in renal diseases is now being understood better. Several progressive renal diseases are characterized with persistent cell proliferation and abnormal production of extracellular matrix by mesengial cells. Understanding mesengial cell proliferation and the factors regulating extracellular matrix metabolism is therefore becoming more important. MMPs have been shown to be produced and excreted from renal glomerular cells and interstitital fibroblast and tubuloepithelial cells have also been shown to excrete MMPs. MMPs function in expansive cell behaviour, embryonic evolution and tissue fibrosis. Production of MMPs are known to increase in inflammation and restructure processes. Data obtained from both experimental and clinical studies has shown the role of MMPs in proliferative glomerulonephritis, hypertensive nephropathy, diabetic nephropathy, HIV nephropathy, toxic nephropathy, obstructive nephropathy, renal cell carcinoma, chronic allograft nephropathy-related fibrosis and in many other renal diseases. In light of these data, therapy options targeting MMPs have become a current issue. Limited data obtained from recent studies are promising about the clinical use of therapies repressing MMPs in future. The roles of MMPs which increase in inflammation and restructure processes in renal diseases and future therapy options are discussed in this review.
On Skew Triangular Matrix Rings
Institute of Scientific and Technical Information of China (English)
Wang Wei-liang; Wang Yao; Ren Yan-li
2016-01-01
Letαbe a nonzero endomorphism of a ring R, n be a positive integer and Tn(R,α) be the skew triangular matrix ring. We show that some properties related to nilpotent elements of R are inherited by Tn(R,α). Meanwhile, we determine the strongly prime radical, generalized prime radical and Behrens radical of the ring R[x;α]/(xn), where R[x;α] is the skew polynomial ring.
Staggered chiral random matrix theory
Osborn, James C
2010-01-01
We present a random matrix theory (RMT) for the staggered lattice QCD Dirac operator. The staggered RMT 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.
Model Reduction via Reducibility Matrix
Institute of Scientific and Technical Information of China (English)
Musa Abdalla; Othman Alsmadi
2006-01-01
In this work, a new model reduction technique is introduced. The proposed technique is derived using the matrix reducibility concept. The eigenvalues of the reduced model are preserved; that is, the reduced model eigenvalues are a subset of the full order model eigenvalues. This preservation of the eigenvalues makes the mathematical model closer to the physical model. Finally, the outcomes of this method are fully illustrated using simulations of two numeric examples.
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.
Coherence matrix of plasmonic beams
DEFF Research Database (Denmark)
Novitsky, Andrey; Lavrinenko, Andrei
2013-01-01
We consider monochromatic electromagnetic beams of surface plasmon-polaritons created at interfaces between dielectric media and metals. We theoretically study non-coherent superpositions of elementary surface waves and discuss their spectral degree of polarization, Stokes parameters, and the for...... of the spectral coherence matrix. We compare the polarization properties of the surface plasmonspolaritons as three-dimensional and two-dimensional fields concluding that the latter is superior....
Random matrix improved subspace clustering
Couillet, Romain
2017-03-06
This article introduces a spectral method for statistical subspace clustering. The method is built upon standard kernel spectral clustering techniques, however carefully tuned by theoretical understanding arising from random matrix findings. We show in particular that our method provides high clustering performance while standard kernel choices provably fail. An application to user grouping based on vector channel observations in the context of massive MIMO wireless communication networks is provided.
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
Topics in Matrix Sampling Algorithms
Boutsidis, Christos
2011-01-01
We study three fundamental problems of Linear Algebra, lying in the heart of various Machine Learning applications, namely: 1)"Low-rank Column-based Matrix Approximation". We are given a matrix A and a target rank k. The goal is to select a subset of columns of A and, by using only these columns, compute a rank k approximation to A that is as good as the rank k approximation that would have been obtained by using all the columns; 2) "Coreset Construction in Least-Squares Regression". We are given a matrix A and a vector b. Consider the (over-constrained) least-squares problem of minimizing ||Ax-b||, over all vectors x in D. The domain D represents the constraints on the solution and can be arbitrary. The goal is to select a subset of the rows of A and b and, by using only these rows, find a solution vector that is as good as the solution vector that would have been obtained by using all the rows; 3) "Feature Selection in K-means Clustering". We are given a set of points described with respect to a large numbe...
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.
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 Hi(x ) (integrals of motion) "]Hi(x ) ,Hj(x ) ]">H (x ) ,Hi(x ) =0 , for all x . In a recent work [Phys. Rev. E 93, 052114 (2016), 10.1103/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 =x0 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.
Lung extracellular matrix and redox regulation.
Watson, Walter H; Ritzenthaler, Jeffrey D; Roman, Jesse
2016-08-01
Pulmonary fibrosis affects millions worldwide and, even though there has been a significant investment in understanding the processes involved in wound healing and maladaptive repair, a complete understanding of the mechanisms responsible for lung fibrogenesis eludes us, and interventions capable of reversing or halting disease progression are not available. Pulmonary fibrosis is characterized by the excessive expression and uncontrolled deposition of extracellular matrix (ECM) proteins resulting in erosion of the tissue structure. Initially considered an 'end-stage' process elicited after injury, these events are now considered pathogenic and are believed to contribute to the course of the disease. By interacting with integrins capable of signal transduction and by influencing tissue mechanics, ECM proteins modulate processes ranging from cell adhesion and migration to differentiation and growth factor expression. In doing so, ECM proteins help orchestrate complex developmental processes and maintain tissue homeostasis. However, poorly controlled deposition of ECM proteins promotes inflammation, fibroproliferation, and aberrant differentiation of cells, and has been implicated in the pathogenesis of pulmonary fibrosis, atherosclerosis and cancer. Considering their vital functions, ECM proteins are the target of investigation, and oxidation-reduction (redox) reactions have emerged as important regulators of the ECM. Oxidative stress invariably accompanies lung disease and promotes ECM expression directly or through the overproduction of pro-fibrotic growth factors, while affecting integrin binding and activation. In vitro and in vivo investigations point to redox reactions as targets for intervention in pulmonary fibrosis and related disorders, but studies in humans have been disappointing probably due to the narrow impact of the interventions tested, and our poor understanding of the factors that regulate these complex reactions. This review is not meant to
Lung extracellular matrix and redox regulation
Directory of Open Access Journals (Sweden)
Walter H. Watson
2016-08-01
Full Text Available Pulmonary fibrosis affects millions worldwide and, even though there has been a significant investment in understanding the processes involved in wound healing and maladaptive repair, a complete understanding of the mechanisms responsible for lung fibrogenesis eludes us, and interventions capable of reversing or halting disease progression are not available. Pulmonary fibrosis is characterized by the excessive expression and uncontrolled deposition of extracellular matrix (ECM proteins resulting in erosion of the tissue structure. Initially considered an ‘end-stage’ process elicited after injury, these events are now considered pathogenic and are believed to contribute to the course of the disease. By interacting with integrins capable of signal transduction and by influencing tissue mechanics, ECM proteins modulate processes ranging from cell adhesion and migration to differentiation and growth factor expression. In doing so, ECM proteins help orchestrate complex developmental processes and maintain tissue homeostasis. However, poorly controlled deposition of ECM proteins promotes inflammation, fibroproliferation, and aberrant differentiation of cells, and has been implicated in the pathogenesis of pulmonary fibrosis, atherosclerosis and cancer. Considering their vital functions, ECM proteins are the target of investigation, and oxidation–reduction (redox reactions have emerged as important regulators of the ECM. Oxidative stress invariably accompanies lung disease and promotes ECM expression directly or through the overproduction of pro-fibrotic growth factors, while affecting integrin binding and activation. In vitro and in vivo investigations point to redox reactions as targets for intervention in pulmonary fibrosis and related disorders, but studies in humans have been disappointing probably due to the narrow impact of the interventions tested, and our poor understanding of the factors that regulate these complex reactions. This
Matrix Superpotential Linear in Variable Parameter
Karadzhov, Yuri
2011-01-01
The paper presents the classification of matrix valued superpotentials corresponding to shape invariant systems of Schr\\"odinger equations. All inequivalent irreducible matrix superpotentials realized by matrices of arbitrary dimension with linear dependence on variable parameter are presented explicitly.
Cubic Matrix, Nambu Mechanics and Beyond
Kawamura, Y
2002-01-01
We propose a generalization of cubic matrix mechanics by introducing a canonical triplet and study its relation to Nambu mechanics. The generalized cubic matrix mechanics we consider can be interpreted as a “quantum” generalization of Nambu mechanics.
"On some definitions in matrix algebra"
Magnus, Jan R.; Karim M. Abadir
2007-01-01
Many definitions in matrix algebra are not standardized. This notediscusses some of thepitfalls associated with undesirable orwrong definitions, anddealswith central conceptslikesymmetry, orthogonality, square root, Hermitian and quadratic forms, and matrix derivatives.
L’Hospital rule for matrix functions
Directory of Open Access Journals (Sweden)
Z.M. Kishka
2013-07-01
Full Text Available In this paper, the L’Hospital rule for evaluating limits of complex matrix functions is introduced. We present some specific examples on certain matrix functions showing the applicability of our approach.
Enamel matrix protein derivatives: role in periodontal regeneration
Directory of Open Access Journals (Sweden)
Rathva VJ
2011-12-01
Full Text Available Vandana J RathvaDepartment of Periodontics, KM Shah Dental College and Hospital, Sumandeep University, Gujarat, IndiaAbstract: The role of regenerative periodontal therapy is the reconstitution of lost periodontal structures, ie, new formation of root cementum, periodontal ligament, and alveolar bone. The outcome of basic research has pointed to the important role of enamel matrix protein derivative (EMD in periodontal wound healing. Histologic results from animal and human studies have shown that treatment with EMD promotes periodontal regeneration. Moreover, clinical studies have indicated that treatment with EMD positively influences periodontal wound healing in humans. The goal of this paper is to review the existing literature on EMD.Keywords: enamel matrix protein derivative, Emdogain®, periodontal regeneration
Institute of Scientific and Technical Information of China (English)
黄小亚; 朱敏; 金笑平; 张丹红; 王灵芝; 叶祖森
2008-01-01
Objective To investigate the association of matrix metalluproteinase-3 (MMP-3) serum level and the promoter 5A/6A polymorphism of theMMP-3 gene with atherosclerotic cerebral infarction (ACI) in a Chinese Hart population.Methods Two hundred and fifteen patients with acute ACI from the Department of Neurology of Taizhou Hospi tal and 226 healthy controls were included in the study.Serum MMP-3 level was measured by enzyme-linked immunosorbent assay (ELISA).Genotype was determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) for the common 5A/6A functional promoter polymorphism of the MMP-3 gene.Results The genotype distribution of the MMP-3 promoter 5A/6A polymorphism between the ACI patients group and the control group was significantly different(X2=9.389,P=0.002).The frequencies of the 5A allele were 14.2%and 7.7%in the ACI patients group and the control group respectively(X2=9.430,P=0.002).Serum level of MMP-3 in the ACI patients group was significantly higher than that in the control group(t=24.867,P=0.000).Among the ACI patients group,serum MMP3 levels also had significant difference between the 5A/6A + 5A/SA and the 6A/6A genotype(t=2.057,P=0.041).Conclusion The present findings suggest that serum level of MMP-3 obviously increased within 48 hours of ischemic stroke and the genetic polymorphism of 5A/6A in the MMP-3 promoter is associated with ACI and MMP-3 expression in the Chinese Han population.%目的 探讨摹质金属蛋白酶-3(matrix metalloproteinase-3,MMP-3)血清水平及启动子基因5A/6A多态性与动脉粥样硬化性脑梗死(atherosclerotic cerebral infarction,ACI)的关系.方法 对215例ACI患者和226名健康体检者进行研究.采用ELISA法测定血清MMP-3水平,同时采用聚合酶链反应-限制性片段长度多态性方法分析MMP-3启动子基因5A/6A多态性.结果 ACI组发病48 h内的血清NIVIP-3水平为(23.28±12.19)ng/μL,较对照组(2.76±2.25)ng/μL显著增高(t=24.867,P=0
Matrix Stiffness–Induced Myofibroblast Differentiation Is Mediated by Intrinsic Mechanotransduction
Huang, Xiangwei; Yang, Naiheng; Fiore, Vincent F.; Barker, Thomas H.; Sun, Yi; Morris, Stephan W.; Ding, Qiang; Thannickal, Victor J.
2012-01-01
The mechanical properties of the extracellular matrix have recently been shown to promote myofibroblast differentiation and lung fibrosis. Mechanisms by which matrix stiffness regulates myofibroblast differentiation are not fully understood. The goal of this study was to determine the intrinsic mechanisms of mechanotransduction in the regulation of matrix stiffness–induced myofibroblast differentiation. A well established polyacrylamide gel system with tunable substrate stiffness was used in this study. Megakaryoblastic leukemia factor-1 (MKL1) nuclear translocation was imaged by confocal immunofluorescent microscopy. The binding of MKL1 to the α-smooth muscle actin (α-SMA) gene promoter was quantified by quantitative chromatin immunoprecipitation assay. Normal human lung fibroblasts responded to matrix stiffening with changes in actin dynamics that favor filamentous actin polymerization. Actin polymerization resulted in nuclear translocation of MKL1, a serum response factor coactivator that plays a central role in regulating the expression of fibrotic genes, including α-SMA, a marker for myofibroblast differentiation. Mouse lung fibroblasts deficient in Mkl1 did not respond to matrix stiffening with increased α-SMA expression, whereas ectopic expression of human MKL1 cDNA restored the ability of Mkl1 null lung fibroblasts to express α-SMA. Furthermore, matrix stiffening promoted production and activation of the small GTPase RhoA, increased Rho kinase (ROCK) activity, and enhanced fibroblast contractility. Inhibition of RhoA/ROCK abrogated stiff matrix–induced actin cytoskeletal reorganization, MKL1 nuclear translocation, and myofibroblast differentiation. This study indicates that actin cytoskeletal remodeling–mediated activation of MKL1 transduces mechanical stimuli from the extracellular matrix to a fibrogenic program that promotes myofibroblast differentiation, suggesting an intrinsic mechanotransduction mechanism. PMID:22461426
SINE TRANSFORM MATRIX FOR SOLVING TOEPLITZ MATRIX PROBLEMS
Institute of Scientific and Technical Information of China (English)
Li-zhi Cheng
2001-01-01
In recent papers, some authors studied the solutions of symmetricpositive definite(SPD) Toeplitz systems Tn x = b by the conjugate gradient method(CG) with different sine trans- forms based preconditioners. In this paper, we first discuss the properties of eigenvalues for the main known circulant, skew circulant and sine transform based preconditioners. A counter example shows that E.Boman's preconditioner is only positive semi-definite for the banded Toeplitz matrix. To use preconditioner effectively, then we propose a modified Boman's preconditioner and a new Cesaro sum type sine transform based preconditioner. Finally, the results of numerical experimentation with these two preconditioners are pre- sented.
Random Matrix theory approach to Quantum mechanics
Chaitanya, K. V. S. Shiv
2015-01-01
In this paper, we give random matrix theory approach to the quantum mechanics using the quantum Hamilton-Jacobi formalism. We show that the bound state problems in quantum mechanics are analogous to solving Gaussian unitary ensemble of random matrix theory. This study helps in identify the potential appear in the joint probability distribution function in the random matrix theory as a super potential. This approach allows to extend the random matrix theory to the newly discovered exceptional ...
Analytic matrix elements with shifted correlated Gaussians
DEFF Research Database (Denmark)
Fedorov, D. V.
2017-01-01
Matrix elements between shifted correlated Gaussians of various potentials with several form-factors are calculated analytically. Analytic matrix elements are of importance for the correlated Gaussian method in quantum few-body physics.......Matrix elements between shifted correlated Gaussians of various potentials with several form-factors are calculated analytically. Analytic matrix elements are of importance for the correlated Gaussian method in quantum few-body physics....
Orthogonal Matrix-Valued Wavelet Packets
Institute of Scientific and Technical Information of China (English)
Qingjiang Chen; Cuiling Wang; Zhengxing Cheng
2007-01-01
In this paper,we introduce matrix-valued multiresolution analysis and matrixvalued wavelet packets. A procedure for the construction of the orthogonal matrix-valued wavelet packets is presented. The properties of the matrix-valued wavelet packets are investigated. In particular,a new orthonormal basis of L2(R,Cs×s) is obtained from the matrix-valued wavelet packets.
Continued Fraction Algorithm for Matrix Exponentials
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
A recursive rational algorithm for matrix exponentials was obtained by making use of the generalized inverse of a matrix in this paper. On the basis of the n-th convergence of Thiele-type continued fraction expansion, a new type of the generalized inverse matrix-valued Padé approximant (GMPA) for matrix exponentials was defined and its remainder formula was proved. The results of this paper were illustrated by some examples.
Project-matrix models of marketing organization
Directory of Open Access Journals (Sweden)
Gutić Dragutin
2009-01-01
Full Text Available Unlike theory and practice of corporation organization, in marketing organization numerous forms and contents at its disposal are not reached until this day. It can be well estimated that marketing organization today in most of our companies and in almost all its parts, noticeably gets behind corporation organization. Marketing managers have always been occupied by basic, narrow marketing activities as: sales growth, market analysis, market growth and market share, marketing research, introduction of new products, modification of products, promotion, distribution etc. They rarely found it necessary to focus a bit more to different aspects of marketing management, for example: marketing planning and marketing control, marketing organization and leading. This paper deals with aspects of project - matrix marketing organization management. Two-dimensional and more-dimensional models are presented. Among two-dimensional, these models are analyzed: Market management/products management model; Products management/management of product lifecycle phases on market model; Customers management/marketing functions management model; Demand management/marketing functions management model; Market positions management/marketing functions management model. .
Molecular events in matrix protein metabolism in the aging kidney.
Sataranatarajan, Kavithalakshmi; Feliers, Denis; Mariappan, Meenalakshmi M; Lee, Hak Joo; Lee, Myung Ja; Day, Robert T; Yalamanchili, Hima Bindu; Choudhury, Goutam G; Barnes, Jeffrey L; Van Remmen, Holly; Richardson, Arlan; Kasinath, Balakuntalam S
2012-12-01
We explored molecular events associated with aging-induced matrix changes in the kidney. C57BL6 mice were studied in youth, middle age, and old age. Albuminuria and serum cystatin C level (an index of glomerular filtration) increased with aging. Renal hypertrophy was evident in middle-aged and old mice and was associated with glomerulomegaly and increase in mesangial fraction occupied by extracellular matrix. Content of collagen types I and III and fibronectin was increased with aging; increment in their mRNA varied with the phase of aging. The content of ZEB1 and ZEB2, collagen type I transcription inhibitors, and their binding to the collagen type Iα2 promoter by ChIP assay also showed age-phase-specific changes. Lack of increase in mRNA and data from polysome assay suggested decreased degradation as a potential mechanism for kidney collagen type I accumulation in the middle-aged mice. These changes occurred with increment in TGFβ mRNA and protein and activation of its SMAD3 pathway; SMAD3 binding to the collagen type Iα2 promoter was also increased. TGFβ-regulated microRNAs (miRs) exhibited selective regulation. The renal cortical content of miR-21 and miR-200c, but not miR-192, miR-200a, or miR-200b, was increased with aging. Increased miR-21 and miR-200c contents were associated with reduced expression of their targets, Sprouty-1 and ZEB2, respectively. These data show that aging is associated with complex molecular events in the kidney that are already evident in the middle age and progress to old age. Age-phase-specific regulation of matrix protein synthesis occurs and involves matrix protein-specific transcriptional and post-transcriptional mechanisms. © 2012 The Authors Aging Cell © 2012 Blackwell Publishing Ltd/Anatomical Society of Great Britain and Ireland.
2013-01-01
The thesis titled Promoting preschool reading consists of a theoretiral and an empirical part. In the theoretical part I wrote about reading, the importance of reading, types of reading, about reading motivation, promoting reading motivation, internal and external motivation, influence of reading motivation on the child's reading activity, reading and familial literacy, the role of adults in promotion reading literacy, reading to a child and promoting reading in pre-school years, where I ...
Robert C. Blattberg; Richard Briesch; Fox, Edward J.
1995-01-01
By synthesizing findings across the sales promotion literature, this article helps the reader understand how promotions work. We identify and explain empirical generalizations related to sales promotion; that is, effects that have been found consistently in multiple studies involving different researchers. We also identify issues which have generated conflicting findings in the research, as well as important sales promotion topics that have not yet been studied. This overview of the research ...
Perceptions of health promoters about health promotion ...
African Journals Online (AJOL)
2013-02-11
Feb 11, 2013 ... formal written health promotion guidelines for families with adolescents orphaned ..... community: '…What worries me is the fact that they still become pregnant .... to learn about HIV risk factors, testing, treatment choices and.
Positivity of Matrices with Generalized Matrix Functions
Institute of Scientific and Technical Information of China (English)
Fuzhen ZHANG
2012-01-01
Using an elementary fact on matrices we show by a unified approach the positivity of a partitioned positive semidefinite matrix with each square block replaced by a compound matrix,an elementary symmetric function or a generalized matrix function.In addition,we present a refined version of the Thompson determinant compression theorem.
Matrix algebra for higher order moments
Meijer, Erik
2005-01-01
A large part of statistics is devoted to the estimation of models from the sample covariance matrix. The development of the statistical theory and estimators has been greatly facilitated by the introduction of special matrices, such as the commutation matrix and the duplication matrix, and the corre
Matrix Sampling of Test Items. ERIC Digest.
Childs, Ruth A.; Jaciw, Andrew P.
This Digest describes matrix sampling of test items as an approach to achieving broad coverage while minimizing testing time per student. Matrix sampling involves developing a complete set of items judged to cover the curriculum, then dividing the items into subsets and administering one subset to each student. Matrix sampling, by limiting the…
An inversion algorithm for general tridiagonal matrix
Institute of Scientific and Technical Information of China (English)
Rui-sheng RAN; Ting-zhu HUANG; Xing-ping LIU; Tong-xiang GU
2009-01-01
An algorithm for the inverse of a general tridiagonal matrix is presented. For a tridiagonal matrix having the Doolittle factorization, an inversion algorithm is established.The algorithm is then generalized to deal with a general tridiagonal matrix without any restriction. Comparison with other methods is provided, indicating low computational complexity of the proposed algorithm, and its applicability to general tridiagonal matrices.
Confocal Microscopy Imaging of the Biofilm Matrix
DEFF Research Database (Denmark)
Schlafer, Sebastian; Meyer, Rikke Louise
2016-01-01
The extracellular matrix is an integral part of microbial biofilms and an important field of research. Confocal laser scanning microscopy is a valuable tool for the study of biofilms, and in particular of the biofilm matrix, as it allows real-time visualization of fully hydrated, living specimens...... the concentration of solutes and the diffusive properties of the biofilm matrix....
Huang, Jian-Wen; Xu, Yue-Min; Li, Zhao-Bo; Murphy, Sean V; Zhao, Weixin; Liu, Qiang-Qiang; Zhu, Wei-Dong; Fu, Qiang; Zhang, Yao-Peng; Song, Lu-Jie
2016-01-01
The goal of this study was to investigate the tissue performance of bladder following stretched electrospun silk fibroin matrix (SESFM) implantation compared with bladder acellular matrix (BAM). We compared SESFM with BAM based on porosity and pore size. Scaffolds were separately transplanted into opposite walls of the bladder of 30 rabbits after stripping the bladder mucosa and smooth muscle (1.5 × 2.0 cm(2)). Gross anatomical observation, histological analysis and muscle contractility studies were performed at 2, 4, and 8 weeks post-op. SESFM has higher porosity and larger pore size compared with BAM (p calculus was evident in 7/10 rabbits. Histological analysis showed that SESFM and BAM promoted similar degree of urothelium regeneration (p > 0.05). However, SESFM promoted a higher degree of smooth muscle and vessel regeneration compared to BAM (p < 0.05). In addition, muscle strips supported by SESFM displayed higher contractile responses to carbachol, KCl, and phenylephrine compared with BAM. At 8 weeks, both matrices elicited similar mild acute and chronic inflammatory reactions. Our results demonstrated that SESFM has greater ability to promote bladder tissue regeneration with structural and functional properties compared to BAM, and with similar biocompatibility. © 2015 Wiley Periodicals, Inc.
Developing a Promotional Video
Epley, Hannah K.
2014-01-01
There is a need for Extension professionals to show clientele the benefits of their program. This article shares how promotional videos are one way of reaching audiences online. An example is given on how a promotional video has been used and developed using iMovie software. Tips are offered for how professionals can create a promotional video and…
Teaching Tip: When a Matrix and Its Inverse Are Stochastic
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.
Contribution of the α8 integrin chain to the expression of extracellular matrix components.
Volkert, Gudrun; Jahn, Angelika; Dinkel, Christina; Fahlbusch, Fabian; Zürn, Christina; Hilgers, Karl F; Rascher, Wolfgang; Hartner, Andrea; Marek, Ines
2014-04-01
In the kidney, the α8 integrin chain (itga8) is expressed in mesenchymal cells and is upregulated in fibrotic disease. We hypothesized that itga8 mediates a profibrotic phenotype of renal cells by promoting extracellular matrix and cytokine expression. Genetic itga8 deficiency caused complex changes in matrix expression patterns in mesangial and smooth-muscle cells, with the only concordant effect in both cell types being a reduction of collagen III expression. Silencing of itga8 with siRNA led to a decline of matrix turnover with repression of matrix metalloproteinases and reduction of matrix production. In contrast, de novo expression of itga8 in tubular epithelial cells resulted in reduced collagen synthesis. Overexpression of itga8 in fibroblasts did not change the expression of matrix molecules or regulators of matrix turnover. Thus, the influence of itga8 on the expression of matrix components was not uniform and celltype dependent. Itga8 seems unlikely to exert overall profibrotic effects in renal cells.
Diagonal representation for a generic matrix valued quantum Hamiltonian
Energy Technology Data Exchange (ETDEWEB)
Gosselin, Pierre [Universite Grenoble I, Institut Fourier, UMR 5582 CNRS-UJF UFR de Mathematiques, BP74, Saint Martin d' Heres Cedex (France); Mohrbach, Herve [Universite Paul Verlaine-Metz, Laboratoire de Physique Moleculaire et des Collisions, ICPMB-FR CNRS 2843, Metz Cedex 3 (France)
2009-12-15
A general method to derive the diagonal representation for a generic matrix valued quantum Hamiltonian is proposed. In this approach new mathematical objects like non-commuting operators evolving with the Planck constant promoted as a running variable are introduced. This method leads to a formal compact expression for the diagonal Hamiltonian which can be expanded in a power series of the Planck constant. In particular, we provide an explicit expression for the diagonal representation of a generic Hamiltonian to the second order in the Planck constant. This result is applied, as a physical illustration, to Dirac electrons and neutrinos in external fields. (orig.)
Diffusive dynamics on paper matrix
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.
Integrable matrix theory: Level statistics
2016-01-01
We study level statistics in ensembles of integrable $N\\times N$ 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) $\\left[H(x),H^i(x)\\right] = 0$, $\\left[H^i(x), H^j(x)\\right]$ = 0, for all $x$. In a recent work, we developed a basis-independent construction of $H(x)$ for any $n$ from which we derived the probability density function, thereby determin...
Matrix Completion from Noisy Entries
Keshavan, Raghunandan H; Oh, Sewoong
2009-01-01
Given a matrix M of low-rank, we consider the problem of reconstructing it from noisy observations of a small, random subset of its entries. The problem arises in a variety of applications, from collaborative filtering (the `Netflix problem') to structure-from-motion and positioning. We study a low complexity algorithm introduced by Keshavan et al.(2009), based on a combination of spectral techniques and manifold optimization, that we call here OptSpace. We prove performance guarantees that are order-optimal in a number of circumstances.
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.
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.
Random Matrix Theory and Econophysics
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
Linear algebra and matrix analysis for statistics
Banerjee, Sudipto
2014-01-01
Matrices, Vectors, and Their OperationsBasic definitions and notations Matrix addition and scalar-matrix multiplication Matrix multiplication Partitioned matricesThe ""trace"" of a square matrix Some special matricesSystems of Linear EquationsIntroduction Gaussian elimination Gauss-Jordan elimination Elementary matrices Homogeneous linear systems The inverse of a matrixMore on Linear EquationsThe LU decompositionCrout's Algorithm LU decomposition with row interchanges The LDU and Cholesky factorizations Inverse of partitioned matrices The LDU decomposition for partitioned matricesThe Sherman-W
MatrixPlot: visualizing sequence constraints
DEFF Research Database (Denmark)
Gorodkin, Jan; Stærfeldt, Hans Henrik; Lund, Ole
1999-01-01
MatrixPlot: visualizing sequence constraints. Sub-title Abstract Summary : MatrixPlot is a program for making high-quality matrix plots, such as mutual information plots of sequence alignments and distance matrices of sequences with known three-dimensional coordinates. The user can add information...... about the sequences (e.g. a sequence logo profile) along the edges of the plot, as well as zoom in on any region in the plot. Availability : MatrixPlot can be obtained on request, and can also be accessed online at http://www. cbs.dtu.dk/services/MatrixPlot. Contact : gorodkin@cbs.dtu.dk...
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.
Singular Value Decomposition for Unitary Symmetric Matrix
Institute of Scientific and Technical Information of China (English)
ZOUHongxing; WANGDianjun; DAIQionghai; LIYanda
2003-01-01
A special architecture called unitary sym-metric matrix which embodies orthogonal, Givens, House-holder, permutation, and row (or column) symmetric ma-trices as its special cases, is proposed, and a precise corre-spondence of singular values and singular vectors between the unitary symmetric matrix and its mother matrix is de-rived. As an illustration of potential, it is shown that, for a class of unitary symmetric matrices, the singular value decomposition (SVD) using the mother matrix rather than the unitary symmetric matrix per se can save dramatically the CPU time and memory without loss of any numerical precision.
MatrixPlot: visualizing sequence constraints
DEFF Research Database (Denmark)
Gorodkin, Jan; Stærfeldt, Hans Henrik; Lund, Ole
1999-01-01
MatrixPlot: visualizing sequence constraints. Sub-title Abstract Summary : MatrixPlot is a program for making high-quality matrix plots, such as mutual information plots of sequence alignments and distance matrices of sequences with known three-dimensional coordinates. The user can add information...... about the sequences (e.g. a sequence logo profile) along the edges of the plot, as well as zoom in on any region in the plot. Availability : MatrixPlot can be obtained on request, and can also be accessed online at http://www. cbs.dtu.dk/services/MatrixPlot. Contact : gorodkin@cbs.dtu.dk...
DEFF Research Database (Denmark)
Lehn-Christiansen, Sine
The paper discusses the implications of health promotion in education. The paper is based on my PhD project entitled “Health promotion education seen through a power/knowledge and subjectification perspective” (in prep). The PhD project explores how professional health promotion skills...... are conceived in a specific educational setting; namely the Danish social and health education programme. Here, health promotion is formally conceived as a qualification aimed at citizens and patients - and not at the students themselves. However, as the paper will demonstrate, conceptions of student...... health promotion workers should ideally act as health promotion role models. This claim leads to a series of educational and morally anchored dilemmas and challenges. Inspired by Foucault and others who have developed this line of thinking (eg. Signild Vallgårde) health promotion is viewed as a heartfelt...
Sparse Matrix Inversion with Scaled Lasso
Sun, Tingni
2012-01-01
We propose a new method of learning a sparse nonnegative-definite target matrix. Our primary example of the target matrix is the inverse of a population covariance matrix or correlation matrix. The algorithm first estimates each column of the matrix by scaled Lasso, a joint estimation of regression coefficients and noise level, and then adjusts the matrix estimator to be symmetric. The procedure is efficient in the sense that the penalty level of the scaled Lasso for each column is completely determined by the data via convex minimization, without using cross-validation. We prove that this method guarantees the fastest proven rate of convergence in the spectrum norm under conditions of weaker form than those in the existing analyses of other $\\ell_1$ algorithms, and has faster guaranteed rate of convergence when the ratio of the $\\ell_1$ and spectrum norms of the target inverse matrix diverges to infinity. A simulation study also demonstrates the competitive performance of the proposed estimator.
Interpolation of rational matrix functions
Ball, Joseph A; Rodman, Leiba
1990-01-01
This book aims to present the theory of interpolation for rational matrix functions as a recently matured independent mathematical subject with its own problems, methods and applications. The authors decided to start working on this book during the regional CBMS conference in Lincoln, Nebraska organized by F. Gilfeather and D. Larson. The principal lecturer, J. William Helton, presented ten lectures on operator and systems theory and the interplay between them. The conference was very stimulating and helped us to decide that the time was ripe for a book on interpolation for matrix valued functions (both rational and non-rational). When the work started and the first partial draft of the book was ready it became clear that the topic is vast and that the rational case by itself with its applications is already enough material for an interesting book. In the process of writing the book, methods for the rational case were developed and refined. As a result we are now able to present the rational case as an indepe...
Solid-matrix luminescence analysis
Energy Technology Data Exchange (ETDEWEB)
Hurtubise, R.J.
1993-01-15
Several interactions with lumiphors adsorbed on filter paper were elucidated from experiments with moisture, modulus and heavy-atom salts. The data were interpreted using static and dynamic quenching models, heavy-atom theory, and a theory related to the modulus of paper. With cyclodextrin-salt matrices, it was shown that 10% [alpha]-cyclodextrin/NaCl was very effective for obtaining strong room-temperature fluorescence and moderate room-temperature phosphorescence from adsorbed stereoisomeric tetrols. Extensive photophysical information was obtained for the four tetrols on 10% [alpha]-cyclodextrin/NaCl. The photophysical information acquired was used to develop a method for characterizing two of the tetrols. Work with model compounds adsorbed on deuterated sodium acetate showed that C-H vibrations in the undeuterated sodium acetate were not responsible for the deactivation of the excited triplet state in the model phosphors investigated. A considerable amount of solution luminescence and solid-matrix luminescence data were compared. The most important finding was that in several cases the room-temperature solid-matrix luminescence quantum yields were greater than the solution low-temperature quantum yield values.
Matrix Crosslinking Forces Tumor Progression by Enhancing Integrin signaling
Levental, Kandice R.; Yu, Hongmei; Kass, Laura; Lakins, Johnathon N.; Egeblad, Mikala; Erler, Janine T.; Fong, Sheri F.T.; Csiszar, Katalin; Giaccia, Amato; Weninger, Wolfgang; Yamauchi, Mitsuo; Gasser, David L.; Weaver, Valerie M.
2009-01-01
Summary Tumors are characterized by extracellular matrix (ECM) remodeling and stiffening. The importance of ECM remodeling to cancer is appreciated; the relevance of stiffening is less clear. We found that breast tumorigenesis is accompanied by collagen crosslinking, ECM stiffening and increased focal adhesions. Inducing collagen crosslinking stiffened the ECM, promoted focal adhesions, enhanced PI3 Kinase (PI3K) activity, and induced the invasion of an oncogene-initiated epithelium. Inhibiting integrin signaling repressed the invasion of a premalignant epithelium into a stiffened, crosslinked ECM, and forced integrin clustering promoted focal adhesions, enhanced PI3K signaling and induced the invasion of a premalignant epithelium. Consistently, reducing lysyl oxidase-mediated collagen crosslinking prevented MMTV-Neu-induced fibrosis, decreased focal adhesions and PI3K activity, impeded malignancy and lowered tumor incidence. These data show how collagen crosslinking can modulate tissue fibrosis and stiffness to force focal adhesions, growth factor signaling and breast malignancy. PMID:19931152
The effect of enamel matrix derivative (Emdogain) on bone formation: a systematic review.
Rathe, F.; Junker, R.; Chesnutt, B.C.; Jansen, J.A.
2009-01-01
This systematic review focused on the question, if and to what extent enamel matrix derivative (Emdogain) [EMD]) promotes the regeneration of bone. The influence of combinations with other biomaterials was additionally evaluated. Twenty histomorphometric studies were included in this systematic revi
Matrix metalloproteinases as therapeutic targets for idiopathic pulmonary fibrosis.
Craig, Vanessa J; Zhang, Li; Hagood, James S; Owen, Caroline A
2015-11-01
Idiopathic pulmonary fibrosis (IPF) is a restrictive lung disease that is associated with high morbidity and mortality. Current medical therapies are not fully effective at limiting mortality in patients with IPF, and new therapies are urgently needed. Matrix metalloproteinases (MMPs) are proteinases that, together, can degrade all components of the extracellular matrix and numerous nonmatrix proteins. MMPs and their inhibitors, tissue inhibitors of MMPs (TIMPs), have been implicated in the pathogenesis of IPF based upon the results of clinical studies reporting elevated levels of MMPs (including MMP-1, MMP-7, MMP-8, and MMP-9) in IPF blood and/or lung samples. Surprisingly, studies of gene-targeted mice in murine models of pulmonary fibrosis (PF) have demonstrated that most MMPs promote (rather than inhibit) the development of PF and have identified diverse mechanisms involved. These mechanisms include MMPs: (1) promoting epithelial-to-mesenchymal transition (MMP-3 and MMP-7); (2) increasing lung levels or activity of profibrotic mediators or reducing lung levels of antifibrotic mediators (MMP-3, MMP-7, and MMP-8); (3) promoting abnormal epithelial cell migration and other aberrant repair processes (MMP-3 and MMP-9); (4) inducing the switching of lung macrophage phenotypes from M1 to M2 types (MMP-10 and MMP-28); and (5) promoting fibrocyte migration (MMP-8). Two MMPs, MMP-13 and MMP-19, have antifibrotic activities in murine models of PF, and two MMPs, MMP-1 and MMP-10, have the potential to limit fibrotic responses to injury. Herein, we review what is known about the contributions of MMPs and TIMPs to the pathogenesis of IPF and discuss their potential as therapeutic targets for IPF.
What do health-promoting schools promote?
DEFF Research Database (Denmark)
Simovska, Venka
2012-01-01
Purpose – The editorial aims to provide a brief overview of the individual contributions to the special issue, and a commentary positioning the contributions within research relating to the health-promoting schools initiative in Europe. Design/methodology/approach – The members of the Schools...... for Health in Europe Research Group were invited to submit their work addressing processes and outcomes in school health promotion to this special issue of Health Education. Additionally, an open call for papers was published on the Health Education web site. Following the traditional double blind peer...... review process, nine submissions were accepted for publication. Five of these are selected to be published in this issue and the rest will be published in a future issue of the journal. Findings – The five articles in this issue take a comprehensive approach to health promotion in schools and reflect...
What do health-promoting schools promote?
DEFF Research Database (Denmark)
Simovska, Venka
2012-01-01
for Health in Europe Research Group were invited to submit their work addressing processes and outcomes in school health promotion to this special issue of Health Education. Additionally, an open call for papers was published on the Health Education web site. Following the traditional double blind peer......Purpose – The editorial aims to provide a brief overview of the individual contributions to the special issue, and a commentary positioning the contributions within research relating to the health-promoting schools initiative in Europe. Design/methodology/approach – The members of the Schools...
Directory of Open Access Journals (Sweden)
Alexandru Lucian MIHAI
2013-10-01
Full Text Available In sport marketing, the word promotion covers a range of interrelated activities. All of these activities are designed to attract attention, stimulate the interest and awareness of consumers, and of course, encourage them to purchase a sport product. Promotion is about communicating with and educating consumers. The purpose of a sport promotional strategy is to build brand loyalty and product credibility, develop image, and position the brand. A promotional strategy is similar to a marketing strategy, but the promotional strategy seeks short-term objectives, both direct and indirect. Promotional objectives usually include increased sales, stimulate impulse buying, raise customer traffic, and present and reinforce image. It also provides information about products and services, publicizes new stores or websites, and creates and enhances customer satisfaction.
On the Matrix Formulation of Kaiser's Varimax Criterion.
Neudecker, H.
1981-01-01
A full-fledged matrix derivation of Sherin's matrix formulation of Kaiser's varimax criterion is provided. Matrix differential calculus is used in conjunction with the Hadamard (or Schur) matrix product. Two results on Hadamard products are presented. (Author/JKS)
Capps, Oral, Jr.; Williams, Gary W.
2007-01-01
This objective of this study is to determine whether the advertising and promotion dollars collected and spent by the American Lamb Board on lamb promotion since the inception of the Lamb Checkoff Program have effectively increased lamb consumption in the United States. The main conclusion is that program has resulted in roughly 7.6 additional pounds of total lamb consumption per dollar spent on advertising and promotion and $41.59 in additional lamb sales per dollar spent on advertising and ...
Distributed-memory matrix computations
DEFF Research Database (Denmark)
Balle, Susanne Mølleskov
1995-01-01
in these algorithms is that many scientific applications rely heavily on the performance of the involved dense linear algebra building blocks. Even though we consider the distributed-memory as well as the shared-memory programming paradigm, the major part of the thesis is dedicated to distributed-memory architectures....... We emphasize distributed-memory massively parallel computers - such as the Connection Machines model CM-200 and model CM-5/CM-5E - available to us at UNI-C and at Thinking Machines Corporation. The CM-200 was at the time this project started one of the few existing massively parallel computers...... performance can we expect to achieve? Why? 2.Solving systems of linear equations using a Strassen-type matrix-inversion algorithm. A good way to solve systems of linear equations on massively parallel computers? 3.Aspects of computing the singular value decomposition on the Connec-tion Machine CM-5/CM-5E...
The Biblical Matrix of Economics
Directory of Open Access Journals (Sweden)
Grigore PIROŞCĂ
2012-05-01
Full Text Available The rationale of this paper is a prime pattern of history of economic thought in the previous ages of classic ancient times of Greek and Roman civilizations using a methodological matrix able to capture the mainstream ideas from social, political and religious events within the pages of Bible. The economic perspective of these events follows the evolution of the seeds of economic thinking within the Fertile Crescent, focused on the Biblical patriarchic heroes’ actions, but also on the empires which their civilization interacted to. The paper aims to discover the path followed by the economic doctrines from the Bible in order to find a match with economic actuality of present days.
Density matrix theory and applications
Blum, Karl
2012-01-01
Written in a clear pedagogic style, this book deals with the application of density matrix theory to atomic and molecular physics. The aim is to precisely characterize sates by a vector and to construct general formulas and proofs of general theorems. The basic concepts and quantum mechanical fundamentals (reduced density matrices, entanglement, quantum correlations) are discussed in a comprehensive way. The discussion leads up to applications like coherence and orientation effects in atoms and molecules, decoherence and relaxation processes. This third edition has been updated and extended throughout and contains a completely new chapter exploring nonseparability and entanglement in two-particle spin-1/2 systems. The text discusses recent studies in atomic and molecular reactions. A new chapter explores nonseparability and entanglement in two-particle spin-1/2 systems.
Buss, Paulo Marchiori; de Carvalho, Antonio Ivo
2007-01-01
The evolution of health promotion within the Brazilian health system is examined, including an assessment of the intersectoral and development policies that have influenced the process. Particular attention is paid to the legal characteristics of the Unified Health System. Human resources formation and research initiatives in health promotion are outlined, with a summary of the obstacles that need to be overcome in order to ensure the effective implementation of health promotion in the future. Up to the end of the 20th Century health promotion was not used as a term in the Brazilian public heath context. Health promoting activities were concentrated in the area of health education, although targeting the social determinants of health and the principle of intersectoral action were part of the rhetoric. The situation has changed during the last decade, with the publication of a national policy of health promotion, issued by the Ministry of Health and jointly implemented with the States and Municipals Health Secretaries. More recently there has been a re-emergence of the discourse on the social determinants of health and the formation of intersectoral public policies as the basis of a comprehensive health promotion. Health promotion infrastructure, particularly around human resources and financing, requires strengthening in order to ensure capacity and sustainability in health promotion practice.
Directory of Open Access Journals (Sweden)
V.V. Bozhkova
2011-03-01
Full Text Available Article describes the classification of promotions and determining the effectiveness of specific measures to stimulate sales (which isnt possible practically in most advertising companies.
Dental Enamel Development: Proteinases and Their Enamel Matrix Substrates
Bartlett, John D.
2013-01-01
This review focuses on recent discoveries and delves in detail about what is known about each of the proteins (amelogenin, ameloblastin, and enamelin) and proteinases (matrix metalloproteinase-20 and kallikrein-related peptidase-4) that are secreted into the enamel matrix. After an overview of enamel development, this review focuses on these enamel proteins by describing their nomenclature, tissue expression, functions, proteinase activation, and proteinase substrate specificity. These proteins and their respective null mice and human mutations are also evaluated to shed light on the mechanisms that cause nonsyndromic enamel malformations termed amelogenesis imperfecta. Pertinent controversies are addressed. For example, do any of these proteins have a critical function in addition to their role in enamel development? Does amelogenin initiate crystallite growth, does it inhibit crystallite growth in width and thickness, or does it do neither? Detailed examination of the null mouse literature provides unmistakable clues and/or answers to these questions, and this data is thoroughly analyzed. Striking conclusions from this analysis reveal that widely held paradigms of enamel formation are inadequate. The final section of this review weaves the recent data into a plausible new mechanism by which these enamel matrix proteins support and promote enamel development. PMID:24159389
Introduction to matrix analysis and applications
Hiai, Fumio
2014-01-01
Matrices can be studied in different ways. They are a linear algebraic structure and have a topological/analytical aspect (for example, the normed space of matrices) and they also carry an order structure that is induced by positive semidefinite matrices. The interplay of these closely related structures is an essential feature of matrix analysis. This book explains these aspects of matrix analysis from a functional analysis point of view. After an introduction to matrices and functional analysis, it covers more advanced topics such as matrix monotone functions, matrix means, majorization and entropies. Several applications to quantum information are also included. Introduction to Matrix Analysis and Applications is appropriate for an advanced graduate course on matrix analysis, particularly aimed at studying quantum information. It can also be used as a reference for researchers in quantum information, statistics, engineering and economics.
Optimized Projection Matrix for Compressive Sensing
Directory of Open Access Journals (Sweden)
Jianping Xu
2010-01-01
Full Text Available Compressive sensing (CS is mainly concerned with low-coherence pairs, since the number of samples needed to recover the signal is proportional to the mutual coherence between projection matrix and sparsifying matrix. Until now, papers on CS always assume the projection matrix to be a random matrix. In this paper, aiming at minimizing the mutual coherence, a method is proposed to optimize the projection matrix. This method is based on equiangular tight frame (ETF design because an ETF has minimum coherence. It is impossible to solve the problem exactly because of the complexity. Therefore, an alternating minimization type method is used to find a feasible solution. The optimally designed projection matrix can further reduce the necessary number of samples for recovery or improve the recovery accuracy. The proposed method demonstrates better performance than conventional optimization methods, which brings benefits to both basis pursuit and orthogonal matching pursuit.
Eigenvalues properties of terms correspondences matrix
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.
Matrix multiplication on the Intel Touchstone Delta
Energy Technology Data Exchange (ETDEWEB)
Huss-Lederman, S.; Jacobson, E.M.; Tsao, A. [Supercomputing Research Center, Bowie, MD (United States); Zhang, G. [CONVEX Computer Corp., Richardson, TX (United States)
1993-12-31
Matrix multiplication is a key primitive in block matrix algorithms such as those found in LAPACK. We present results from our study of matrix multiplication algorithms on the Intel Touchstone Delta, a distributed memory message-passing architecture with a two-dimensional mesh topology. We obtain an implementation that uses communication primitives highly suited to the Delta and exploits the single node assembly-coded matrix multiplication. Our algorithm is completely general, able to deal with arbitrary mesh aspect ratios and matrix dimensions, and has achieved parallel efficiency of 86% with overall peak performance in excess of 8 Gflops on 256 nodes for an 8800 {times} 8800 matrix. We describe our algorithm design and implementation, and present performance results that demonstrate scalability and robust behavior over varying mesh topologies.
Directory of Open Access Journals (Sweden)
D Kuraitis
2012-09-01
Full Text Available Biomaterial-guided regeneration represents a novel approach for the treatment of myopathies. Revascularisation and the intramuscular extracellular matrix are important factors in stimulating myogenesis and regenerating muscle damaged by ischaemia. In this study, we used an injectable collagen matrix, enhanced with sialyl LewisX (sLeX, to guide skeletal muscle differentiation and regeneration. The elastic properties of collagen and sLeX-collagen matrices were similar to those of skeletal muscle, and culture of pluripotent mESCs on the matrices promoted their differentiation into myocyte-like cells expressing Pax3, MHC3, myogenin and Myf5. The regenerative properties of matrices were evaluated in ischaemic mouse hind-limbs. Treatment with the sLeX-matrix augmented the production of myogenic-mediated factors insulin-like growth factor (IGF-1, and IGF binding protein-2 and -5 after 3 days. This was followed by muscle regeneration, including a greater number of regenerating myofibres and increased transcription of Six1, M-cadherin, myogenin and Myf5 after 10 days. Simultaneously, the sLeX-matrix promoted increased mobilisation and engraftment of bone marrow-derived progenitor cells, the development of larger arterioles and the restoration of tissue perfusion. Both matrix treatments tended to reduce maximal forces of ischaemic solei muscles, but sLeX-matrix lessened this loss of force and also prevented muscle fatigue. Only sLeX-matrix treatment improved mobility of mice on a treadmill. Together, these results suggest a novel approach for regenerative myogenesis, whereby treatment only with a matrix, which possesses an inherent ability to guide myogenic differentiation of pluripotent stem cells, can enhance the endogenous vascular and myogenic regeneration of skeletal muscle, thus holding promise for future clinical use.
Kuraitis, D; Ebadi, D; Zhang, P; Rizzuto, E; Vulesevic, B; Padavan, D T; Al Madhoun, A; McEwan, K A; Sofrenovic, T; Nicholson, K; Whitman, S C; Mesana, T G; Skerjanc, I S; Musarò, A; Ruel, M; Suuronen, E J
2012-09-12
Biomaterial-guided regeneration represents a novel approach for the treatment of myopathies. Revascularisation and the intramuscular extracellular matrix are important factors in stimulating myogenesis and regenerating muscle damaged by ischaemia. In this study, we used an injectable collagen matrix, enhanced with sialyl LewisX (sLeX), to guide skeletal muscle differentiation and regeneration. The elastic properties of collagen and sLeX-collagen matrices were similar to those of skeletal muscle, and culture of pluripotent mESCs on the matrices promoted their differentiation into myocyte-like cells expressing Pax3, MHC3, myogenin and Myf5. The regenerative properties of matrices were evaluated in ischaemic mouse hind-limbs. Treatment with the sLeX-matrix augmented the production of myogenic-mediated factors insulin-like growth factor (IGF)-1, and IGF binding protein-2 and -5 after 3 days. This was followed by muscle regeneration, including a greater number of regenerating myofibres and increased transcription of Six1, M-cadherin, myogenin and Myf5 after 10 days. Simultaneously, the sLeX-matrix promoted increased mobilisation and engraftment of bone marrow-derived progenitor cells, the development of larger arterioles and the restoration of tissue perfusion. Both matrix treatments tended to reduce maximal forces of ischaemic solei muscles, but sLeX-matrix lessened this loss of force and also prevented muscle fatigue. Only sLeX-matrix treatment improved mobility of mice on a treadmill. Together, these results suggest a novel approach for regenerative myogenesis, whereby treatment only with a matrix, which possesses an inherent ability to guide myogenic differentiation of pluripotent stem cells, can enhance the endogenous vascular and myogenic regeneration of skeletal muscle, thus holding promise for future clinical use.
Institute of Scientific and Technical Information of China (English)
魏桂枝; 刘晶霞; 徐萍萍; 倪兵; 刘禄斌; 梁志清
2015-01-01
目的 探讨猪膀胱细胞外基质(urinary bladder matrix,UBM)上的Laminin蛋白对大鼠骨髓间充质干细胞(bone marrow mesenchymal stem cells,BMSCs)增殖和向平滑肌分化的影响.方法 采用机械分离法、酶消化法及冷冻干燥法等方法对新鲜猪膀胱进行脱细胞处理,采用蛋白与支架共孵育,制备出UBM+Laminin及UBM+Anti-Laminin复合支架.采用贴壁法培养BMSCs,流式细胞仪鉴定BMSCs.采用P3代BMSCs,分别接种于UBM+Laminin、UBM及UBM+Anti-Laminin上.采用CCK-8检测、HE染色观察及免疫组化鉴定等方法检测Laminin蛋白对BMSCs增殖、迁移和分化的影响.结果 流式细胞仪鉴定BMSCs CD29阳性表达率为98％,CD31阳性表达率为4.56％,CD34阳性率为3.30％.3种材料均能支持BMSCs生长,且随共孵育时间的延长,D(450)值逐渐升高,其中UBM+Laminin复合材料组细胞D(450)最高(P＜0.01).HE染色结果显示UBM+ Laminin组细胞接种第3天形成黏附层,并向深部迁移,第14天可达材料致密层;UBM组第7天仅少许细胞向深层迁移,第14天未达基底层;UBM+Anti-Laminin组仅在支架表层生长.免疫组化检测显示UBM+Laminin组、UBM组、UBM+ Anti-Laminin组细胞α-SMA表达分别呈阳性、弱阳性和阴性.结论 UBM材料上Laminin蛋白能促进负载BMSCs增殖、迁移、并有诱导其向平滑肌方向分化的作用.
Schauer, Kevin L.; LeMoine, Christophe M. R.; Pelin, Adrian; Corradi, Nicolas; Warren, Wesley C.; Grosell, Martin
2016-01-01
Marine teleost fish produce CaCO3 in their intestine as part of their osmoregulatory strategy. This precipitation is critical for rehydration and survival of the largest vertebrate group on earth, yet the molecular mechanisms that regulate this reaction are unknown. Here, we isolate and characterize an organic matrix associated with the intestinal precipitates produced by Gulf toadfish (Opsanus beta). Toadfish precipitates were purified using two different methods, and the associated organic matrix was extracted. Greater than 150 proteins were identified in the isolated matrix by mass spectrometry and subsequent database searching using an O. beta transcriptomic sequence library produced here. Many of the identified proteins were enriched in the matrix compared to the intestinal fluid, and three showed no substantial homology to any previously characterized protein in the NCBI database. To test the functionality of the isolated matrix, a micro-modified in vitro calcification assay was designed, which revealed that low concentrations of isolated matrix substantially promoted CaCO3 production, where high concentrations showed an inhibitory effect. High concentrations of matrix also decreased the incorporation of magnesium into the forming mineral, potentially providing an explanation for the variability in magnesium content observed in precipitates produced by different fish species. PMID:27694946
Schauer, Kevin L.; Lemoine, Christophe M. R.; Pelin, Adrian; Corradi, Nicolas; Warren, Wesley C.; Grosell, Martin
2016-10-01
Marine teleost fish produce CaCO3 in their intestine as part of their osmoregulatory strategy. This precipitation is critical for rehydration and survival of the largest vertebrate group on earth, yet the molecular mechanisms that regulate this reaction are unknown. Here, we isolate and characterize an organic matrix associated with the intestinal precipitates produced by Gulf toadfish (Opsanus beta). Toadfish precipitates were purified using two different methods, and the associated organic matrix was extracted. Greater than 150 proteins were identified in the isolated matrix by mass spectrometry and subsequent database searching using an O. beta transcriptomic sequence library produced here. Many of the identified proteins were enriched in the matrix compared to the intestinal fluid, and three showed no substantial homology to any previously characterized protein in the NCBI database. To test the functionality of the isolated matrix, a micro-modified in vitro calcification assay was designed, which revealed that low concentrations of isolated matrix substantially promoted CaCO3 production, where high concentrations showed an inhibitory effect. High concentrations of matrix also decreased the incorporation of magnesium into the forming mineral, potentially providing an explanation for the variability in magnesium content observed in precipitates produced by different fish species.
Extracellular matrix proteins regulate epithelial-mesenchymal transition in mammary epithelial cells
Chen, Qike K.; Lee, KangAe; Radisky, Derek C.; Nelson, Celeste M.
2013-01-01
Mouse mammary epithelial cells undergo transdifferentiation via epithelial-mesenchymal transition (EMT) upon treatment with matrix metalloproteinase-3 (MMP3). In rigid microenvironments, MMP3 upregulates expression of Rac1b, which translocates to the cell membrane to promote induction of reactive oxygen species and EMT. Here we examine the role of the extracellular matrix (ECM) in this process. Our data show that the basement membrane protein laminin suppresses the EMT response in MMP3-treated cells, whereas fibronectin promotes EMT. These ECM proteins regulate EMT via interactions with their specific integrin receptors. α6-integrin sequesters Rac1b from the membrane and is required for inhibition of EMT by laminin. In contrast, α5-integrin maintains Rac1b at the membrane and is required for the promotion of EMT by fibronectin. Understanding the regulatory role of the ECM will provide insight into mechanisms underlying normal and pathological development of the mammary gland. PMID:23660532
Cassatella-Contra, Giovanni A
2011-01-01
In this paper matrix orthogonal polynomials in the real line are described in terms of a Riemann--Hilbert problem. This approach provides an easy derivation of discrete equations for the corresponding matrix recursion coefficients. The discrete equation is explicitly derived in the matrix Freud case, associated with matrix quartic potentials. It is shown that, when the initial condition and the measure are simultaneously triangularizable, this matrix discrete equation possesses the singularity confinement property, independently if the solution under consideration is given by recursion coefficients to quartic Freud matrix orthogonal polynomials or not.
Micromechanical Evaluation of Ceramic Matrix Composites
1991-02-01
Materials Sciences Corporation AD-A236 756 M.hM. 9 1 0513 IEIN HIfINU IIl- DTIC JUN 06 1991 MICROMECHANICAL EVALUATION OF S 0 CERAMIC MATRIX COMPOSITES C...Classification) \\() Micromechanical Evaluation of Ceramic Matrix Composites ) 12. PERSONAL AUTHOR(S) C-F. Yen, Z. Hashin, C. Laird, B.W. Rosen, Z. Wang 13a. TYPE...and strengthen the ceramic composites. In this task, various possibilities of crack propagation in unidirectional ceramic matrix composites under
String Interactions in c=1 Matrix Model
De Boer, J; Verlinde, E; Yee, J T; Boer, Jan de; Sinkovics, Annamaria; Verlinde, Erik; Yee, Jung-Tay
2004-01-01
We study string interactions in the fermionic formulation of the c=1 matrix model. We give a precise nonperturbative description of the rolling tachyon state in the matrix model, and discuss S-matrix elements of the c=1 string. As a first step to study string interactions, we compute the interaction of two decaying D0-branes in terms of free fermions. This computation is compared with the string theory cylinder diagram using the rolling tachyon ZZ boundary states.
Imposing causality on a matrix model
Energy Technology Data Exchange (ETDEWEB)
Benedetti, Dario [Perimeter Institute for Theoretical Physics, 31 Caroline St. N, N2L 2Y5, Waterloo ON (Canada)], E-mail: dbenedetti@perimeterinstitute.ca; Henson, Joe [Perimeter Institute for Theoretical Physics, 31 Caroline St. N, N2L 2Y5, Waterloo ON (Canada)
2009-07-13
We introduce a new matrix model that describes Causal Dynamical Triangulations (CDT) in two dimensions. In order to do so, we introduce a new, simpler definition of 2D CDT and show it to be equivalent to the old one. The model makes use of ideas from dually weighted matrix models, combined with multi-matrix models, and can be studied by the method of character expansion.
Query Through Heterogeneous Ontologies Using Association Matrix
Institute of Scientific and Technical Information of China (English)
KANG Da-zhou; XU Bao-wen; LU Jian-jiang; WANG Peng; LI Yan-hui
2004-01-01
This paper introduces the definition and calculation of the association matrix between ontologies.It uses the association matrix to describe the relations between concepts in different ontologies and uses concept vectors to represent queries; then computes the vectors with the association matrix in order to rewrite queries.This paper proposes a simple method of querying through heterogeneous Ontology using association matrix.This method is based on the correctness of approximate information filtering theory; and it is simple to be implemented and expected to run quite fast.
Multiscale Modeling of Ceramic Matrix Composites
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.
Risk matrix model for rotating equipment
Directory of Open Access Journals (Sweden)
Wassan Rano Khan
2014-07-01
Full Text Available Different industries have various residual risk levels for their rotating equipment. Accordingly the occurrence rate of the failures and associated failure consequences categories are different. Thus, a generalized risk matrix model is developed in this study which can fit various available risk matrix standards. This generalized risk matrix will be helpful to develop new risk matrix, to fit the required risk assessment scenario for rotating equipment. Power generation system was taken as case study. It was observed that eight subsystems were under risk. Only vibration monitor system was under high risk category, while remaining seven subsystems were under serious and medium risk categories.
Basic matrix algebra and transistor circuits
Zelinger, G
1963-01-01
Basic Matrix Algebra and Transistor Circuits deals with mastering the techniques of matrix algebra for application in transistors. This book attempts to unify fundamental subjects, such as matrix algebra, four-terminal network theory, transistor equivalent circuits, and pertinent design matters. Part I of this book focuses on basic matrix algebra of four-terminal networks, with descriptions of the different systems of matrices. This part also discusses both simple and complex network configurations and their associated transmission. This discussion is followed by the alternative methods of de
New recursive algorithm for matrix inversion
Institute of Scientific and Technical Information of China (English)
Cao Jianshu; Wang Xuegang
2008-01-01
To reduce the computational complexity of matrix inversion, which is the majority of processing in many practical applications, two numerically efficient recursive algorithms (called algorithms Ⅰ and Ⅱ, respectively)are presented. Algorithm Ⅰ is used to calculate the inverse of such a matrix, whose leading principal minors are all nonzero. Algorithm Ⅱ, whereby, the inverse of an arbitrary nonsingular matrix can be evaluated is derived via improving the algorithm Ⅰ. The implementation, for algorithm Ⅱ or Ⅰ, involves matrix-vector multiplications and vector outer products. These operations are computationally fast and highly parallelizable. MATLAB simulations show that both recursive algorithms are valid.
A random matrix theory of decoherence
Gorin, T.; Pineda, C.; Kohler, H.; Seligman, T. H.
2008-11-01
Random matrix theory is used to represent generic loss of coherence of a fixed central system coupled to a quantum-chaotic environment, represented by a random matrix ensemble, via random interactions. We study the average density matrix arising from the ensemble induced, in contrast to previous studies where the average values of purity, concurrence and entropy were considered; we further discuss when one or the other approach is relevant. The two approaches agree in the limit of large environments. Analytic results for the average density matrix and its purity are presented in linear response approximation. The two-qubit system is analysed, mainly numerically, in more detail.
Partitioned R-matrix theory for molecules
Energy Technology Data Exchange (ETDEWEB)
Tennyson, Jonathan [Department of Physics and Astronomy, University College London, Gower St., London WC1E 6BT (United Kingdom)
2004-03-14
R-matrix calculations usually require all the eigenvalues and eigenvectors of the inner region Hamiltonian matrix. For molecular problems, particularly when large configuration interaction expansions are used for the target, the Hamiltonian matrix is often too large to be completely diagonalized. Berrington and Ballance (2002 J. Phys. B: At. Mol. Opt. Phys. 35 2275) proposed a partitioned R-matrix theory which only required a proportion of the solutions of the Hamiltonian matrix. This theory was implemented and tested in the atomic R-matrix code. The theory is adapted to the needs of R-matrix calculations on low-energy electron-molecule collisions. A number of alternative procedures are tested. The best is shown to give reliable results with explicit inclusion of only a fraction of the solutions. It is shown that with this revised theory the number of solutions required does not depend on the complexity of the target wavefunction even though this strongly influences the size of the final Hamiltonian matrix. This method will be implemented as part of the UK molecular R-matrix program suite.
A random matrix theory of decoherence
Energy Technology Data Exchange (ETDEWEB)
Gorin, T [Departamento de FIsica, Universidad de Guadalajara, Blvd Marcelino GarcIa Barragan y Calzada OlImpica, Guadalajara CP 44840, JalIsco (Mexico); Pineda, C [Institut fuer Physik und Astronomie, University of Potsdam, 14476 Potsdam (Germany); Kohler, H [Fachbereich Physik, Universitaet Duisburg-Essen, D-47057 Duisburg (Germany); Seligman, T H [Instituto de Ciencias FIsicas, Universidad Nacional Autonoma de Mexico (Mexico)], E-mail: thomas.gorin@red.cucei.udg.mx, E-mail: carlospgmat03@gmail.com
2008-11-15
Random matrix theory is used to represent generic loss of coherence of a fixed central system coupled to a quantum-chaotic environment, represented by a random matrix ensemble, via random interactions. We study the average density matrix arising from the ensemble induced, in contrast to previous studies where the average values of purity, concurrence and entropy were considered; we further discuss when one or the other approach is relevant. The two approaches agree in the limit of large environments. Analytic results for the average density matrix and its purity are presented in linear response approximation. The two-qubit system is analysed, mainly numerically, in more detail.
Developed Matrix inequalities via Positive Multilinear Mappings
Dehghani, Mahdi; Kian, Mohsen; Seo, Yuki
2015-01-01
Utilizing the notion of positive multilinear mappings, we give some matrix inequalities. In particular, Choi--Davis--Jensen and Kantorovich type inequalities including positive multilinear mappings are presented.
Matrix Krylov subspace methods for image restoration
Directory of Open Access Journals (Sweden)
khalide jbilou
2015-09-01
Full Text Available In the present paper, we consider some matrix Krylov subspace methods for solving ill-posed linear matrix equations and in those problems coming from the restoration of blurred and noisy images. Applying the well known Tikhonov regularization procedure leads to a Sylvester matrix equation depending the Tikhonov regularized parameter. We apply the matrix versions of the well known Krylov subspace methods, namely the Least Squared (LSQR and the conjugate gradient (CG methods to get approximate solutions representing the restored images. Some numerical tests are presented to show the effectiveness of the proposed methods.
A Generalization of the Alias Matrix
DEFF Research Database (Denmark)
Kulahci, Murat; Bisgaard, S.
2006-01-01
The investigation of aliases or biases is important for the interpretation of the results from factorial experiments. For two-level fractional factorials this can be facilitated through their group structure. For more general arrays the alias matrix can be used. This tool is traditionally based...... on the assumption that the error structure is that associated with ordinary least squares. For situations where that is not the case, we provide in this article a generalization of the alias matrix applicable under the generalized least squares assumptions. We also show that for the special case of split plot error...... structure, the generalized alias matrix simplifies to the ordinary alias matrix....
Faster Algorithms for Rectangular Matrix Multiplication
Gall, François Le
2012-01-01
Let {\\alpha} be the maximal value such that the product of an n x n^{\\alpha} matrix by an n^{\\alpha} x n matrix can be computed with n^{2+o(1)} arithmetic operations. In this paper we show that \\alpha>0.30298, which improves the previous record \\alpha>0.29462 by Coppersmith (Journal of Complexity, 1997). More generally, we construct a new algorithm for multiplying an n x n^k matrix by an n^k x n matrix, for any value k\
Titanium Matrix Composite Pressure Vessel Project
National Aeronautics and Space Administration — For over 15 years, FMW Composite Systems has developed Metal Matrix Composite manufacturing methodologies for fabricating silicon-carbide-fiber-reinforced titanium...
Nijveen, H.; Matus-Garcia, M.; Passel, van M.W.J.
2012-01-01
Anecdotal evidence shows promoters being reused separate from their downstream gene, thus providing a mechanism for the efficient and rapid rewiring of a gene’s transcriptional regulation. We have identified over 4000 groups of highly similar promoters using a conservative sequence similarity search
Zhong, Zai-Zhe
2004-01-01
The partial separability of multipartite qubit density matrixes is strictly defined. We give a reduction way from N-partite qubit density matrixes to bipartite qubit density matrixes, and prove a necessary condition that a N-partite qubit density matrix to be partially separable is its reduced density matrix to satisfy PPT condition.
Zhong, Zai-Zhe
2004-01-01
The partial separability of multipartite qubit density matrixes is strictly defined. We give a reduction way from N-partite qubit density matrixes to bipartite qubit density matrixes, and prove a necessary condition that a N-partite qubit density matrix to be partially separable is its reduced density matrix to satisfy PPT condition.
DEFF Research Database (Denmark)
Kwan, Stella Y L; Petersen, Poul Erik; Pine, Cynthia M
2005-01-01
Schools provide an important setting for promoting health, as they reach over 1 billion children worldwide and, through them, the school staff, families and the community as a whole. Health promotion messages can be reinforced throughout the most influential stages of children's lives, enabling...... them to develop lifelong sustainable attitudes and skills. Poor oral health can have a detrimental effect on children's quality of life, their performance at school and their success in later life. This paper examines the global need for promoting oral health through schools. The WHO Global School...... Health Initiative and the potential for setting up oral health programmes in schools using the health-promoting school framework are discussed. The challenges faced in promoting oral health in schools in both developed and developing countries are highlighted. The importance of using a validated...
Soumian, S; Gibbs, R.; Davies, A.; Albrecht, C.
2005-01-01
Background: Atherosclerotic plaque behaviour is influenced by intraplaque inflammation, matrix turnover, and the lipid core volume. Peroxisome proliferator activated receptor γ (PPARγ) modulates atherosclerosis by its anti-inflammatory and anti-protease activity. PPARγ promotes lipid efflux through the liver X receptor α (LXRα) and the ATP binding cassette transporter A1 (ABCA1). Matrix metalloproteinase 9 (MMP-9) and cyclooxygenase 2 (COX-2) are implicated in plaque instability.
Wei, SC; Fattet, L; Tsai, JH; Guo, Y.; Pai, VH; Majeski, HE; Chen, AC; Sah, RL; Taylor, SS; ENGLER, AJ; Yang, J.
2015-01-01
© 2015 Macmillan Publishers Limited. Matrix stiffness potently regulates cellular behaviour in various biological contexts. In breast tumours, the presence of dense clusters of collagen fibrils indicates increased matrix stiffness and correlates with poor survival. It is unclear how mechanical inputs are transduced into transcriptional outputs to drive tumour progression. Here we report that TWIST1 is an essential mechanomediator that promotes epithelial-mesenchymal transition (EMT) in respon...
TRASYS form factor matrix normalization
Tsuyuki, Glenn T.
1992-01-01
A method has been developed for adjusting a TRASYS enclosure form factor matrix to unity. This approach is not limited to closed geometries, and in fact, it is primarily intended for use with open geometries. The purpose of this approach is to prevent optimistic form factors to space. In this method, nodal form factor sums are calculated within 0.05 of unity using TRASYS, although deviations as large as 0.10 may be acceptable, and then, a process is employed to distribute the difference amongst the nodes. A specific example has been analyzed with this method, and a comparison was performed with a standard approach for calculating radiation conductors. In this comparison, hot and cold case temperatures were determined. Exterior nodes exhibited temperature differences as large as 7 C and 3 C for the hot and cold cases, respectively when compared with the standard approach, while interior nodes demonstrated temperature differences from 0 C to 5 C. These results indicate that temperature predictions can be artificially biased if the form factor computation error is lumped into the individual form factors to space.
Direct Model Checking Matrix Algorithm
Institute of Scientific and Technical Information of China (English)
Zhi-Hong Tao; Hans Kleine Büning; Li-Fu Wang
2006-01-01
During the last decade, Model Checking has proven its efficacy and power in circuit design, network protocol analysis and bug hunting. Recent research on automatic verification has shown that no single model-checking technique has the edge over all others in all application areas. So, it is very difficult to determine which technique is the most suitable for a given model. It is thus sensible to apply different techniques to the same model. However, this is a very tedious and time-consuming task, for each algorithm uses its own description language. Applying Model Checking in software design and verification has been proved very difficult. Software architectures (SA) are engineering artifacts that provide high-level and abstract descriptions of complex software systems. In this paper a Direct Model Checking (DMC) method based on Kripke Structure and Matrix Algorithm is provided. Combined and integrated with domain specific software architecture description languages (ADLs), DMC can be used for computing consistency and other critical properties.
Three-dimensional collagen matrix induces a mechanosensitive invasive epithelial phenotype
Carey, Shawn P.; Martin, Karen E.; Reinhart-King, Cynthia A.
2017-01-01
A critical step in breast cancer progression is local tissue invasion, during which cells pass from the epithelial compartment to the stromal compartment. We recently showed that malignant leader cells can promote the invasion of otherwise non-invasive epithelial follower cells, but the effects of this induced-invasion phenomenon on follower cell phenotype remain unclear. Notably, this process can expose epithelial cells to the stromal extracellular matrix (ECM), which is distinct from the ECM within the normal epithelial microenvironment. Here, we used a 3D epithelial morphogenesis model in which cells were cultured in biochemically and mechanically defined matrices to examine matrix-mediated gene expression and the associated phenotypic response. We found that 3D collagen matrix promoted expression of mesenchymal genes including MT1-MMP, which was required for collagen-stimulated invasive behavior. Epithelial invasion required matrix anchorage as well as signaling through Src, PI3K, and Rac1, and increasingly stiff collagen promoted dispersive epithelial cell invasion. These results suggest that leader cell-facilitated access to the stromal ECM may trigger an invasive phenotype in follower epithelial cells that could enable them to actively participate in local tissue invasion. PMID:28186196
Peterson, Chris J; Dosch, Jerald J; Carson, Walter P
2014-08-01
The nucleation hypothesis appears to explain widespread patterns of succession in tropical pastures, specifically the tendency for isolated trees to promote woody species recruitment. Still, the nucleation hypothesis has usually been tested explicitly for only short durations and in some cases isolated trees fail to promote woody recruitment. Moreover, at times, nucleation occurs in other key habitat patches. Thus, we propose an extension, the matrix discontinuity hypothesis: woody colonization will occur in focal patches that function to mitigate the herbaceous vegetation effects, thus providing safe sites or regeneration niches. We tested predictions of the classical nucleation hypothesis, the matrix discontinuity hypothesis, and a distance from forest edge hypothesis, in five abandoned pastures in Costa Rica, across the first 11 years of succession. Our findings confirmed the matrix discontinuity hypothesis: specifically, rotting logs and steep slopes significantly enhanced woody colonization. Surprisingly, isolated trees did not consistently significantly enhance recruitment; only larger trees did so. Finally, woody recruitment consistently decreased with distance from forest. Our results as well as results from others suggest that the nucleation hypothesis needs to be broadened beyond its historical focus on isolated trees or patches; the matrix discontinuity hypothesis focuses attention on a suite of key patch types or microsites that promote woody species recruitment. We argue that any habitat discontinuities that ameliorate the inhibition by dense graminoid layers will be foci for recruitment. Such patches could easily be manipulated to speed the transition of pastures to closed canopy forests.
Hybrid Matrix Grafts to Favor Tissue Regeneration in Rabbit Femur Bone Lesions
Goy, Dante Pascual; Gorosito, Emmanuel; Costa, Hermes S; Mortarino, Pablo; Pedemonte, Noelia Acosta; Toledo, Javier; Mansur, Herman S; Pereira, Marivalda M; Battaglino, Ricardo; Feldman, Sara
2012-01-01
At present, typical approaches employed to repair fractures and other bone lesions tend to use matrix grafts to promote tissue regeneration. These grafts act as templates, which promote cellular adhesion, growth and proliferation, osteoconduction, and even osteoinduction, which commonly results in de novo osteogenesis. The present work aimed to study the bone-repairing ability of hybrid matrixes (HM) prepared with polyvinyl alcohol (PVA) and bioactive glass in an experimental rabbit model. The HM were prepared by combining 30% bioactive glass (nominal composition of 58% SiO2 -33 % CaO - 9% P2O5) and 70% PVA. New Zealand rabbits were randomly divided into the control group (C group) and two groups with bone lesions, in which one received a matrix implant HM (Implant group), while the other did not (no Implant group). Clinical monitoring showed no altered parameters from either the Implant or the no Implant groups as compared to the control group, for the variables of diet grades, day and night temperatures and hemograms. In the Implant group, radiologic and tomographic studies showed implanted areas with clean edges in femoral non-articular direction, and radio-dense images that suggest incipient integration. Minimum signs of phlogosis could be observed, whereas no signs of rejection at this imaging level could be identified. Histological analysis showed evidence of osteo-integration, with the formation of a trabecular bone within the implant. Together, these results show that implants of hybrid matrixes of bioactive glass are capable of promoting bone regeneration. PMID:22848334
Matrix stiffness determines the fate of nucleus pulposus-derived stem cells.
Navaro, Yosi; Bleich-Kimelman, Nadav; Hazanov, Lena; Mironi-Harpaz, Iris; Shachaf, Yonatan; Garty, Shai; Smith, Yoav; Pelled, Gadi; Gazit, Dan; Seliktar, Dror; Gazit, Zulma
2015-05-01
Intervertebral disc (IVD) degeneration and consequent low-back pain present a major medical challenge. Nucleus pulposus-derived stem cells (NP-SCs) may lead to a novel therapy for this severe disease. It was recently shown that survival and function of mature NP cells are regulated in part by tissue stiffness. We hypothesized that modification of matrix stiffness will influence the ability of cultured NP-SCs to proliferate, survive, and differentiate into mature NP cells. NP-SCs were subcultured in three-dimensional matrices of varying degrees of stiffness as measured by the material's shear storage modulus. Cell survival, activity, and rate of differentiation toward the chondrogenic or osteogenic lineage were analyzed. NP-SCs were found to proliferate and differentiate in all matrices, irrespective of matrix stiffness. However, matrices with a low shear storage modulus (G' = 1 kPa) promoted significantly more proliferation and chondrogenic differentiation, whereas matrices with a high modulus (G' = 2 kPa) promoted osteogenic differentiation. Imaging performed via confocal and scanning electron microscopes validated cell survival and highlighted stiffness-dependent cell-matrix interactions. These results underscore the effect of the matrix modulus on the fate of NP-SCs. This research may facilitate elucidation of the complex cross-talk between NP-SCs and their surrounding matrix in healthy as well as pathological conditions.
Jenkins, Molly H; Alrowaished, Sarah S; Goody, Michelle F; Crawford, Bryan D; Henry, Clarissa A
2016-01-01
Remodeling of the extracellular matrix (ECM) regulates cell adhesion as well as signaling between cells and their microenvironment. Despite the importance of tightly regulated ECM remodeling for normal muscle development and function, mechanisms underlying ECM remodeling in vivo remain elusive. One excellent paradigm in which to study ECM remodeling in vivo is morphogenesis of the myotendinous junction (MTJ) during zebrafish skeletal muscle development. During MTJ development, there are dramatic shifts in the primary components comprising the MTJ matrix. One such shift involves the replacement of Fibronectin (Fn)-rich matrix, which is essential for both somite and early muscle development, with laminin-rich matrix essential for normal function of the myotome. Here, we investigate the mechanism underlying this transition. We show that laminin polymerization indirectly promotes Fn downregulation at the MTJ, via a matrix metalloproteinase 11 (Mmp11)-dependent mechanism. Laminin deposition and organization is required for localization of Mmp11 to the MTJ, where Mmp11 is both necessary and sufficient for Fn downregulation in vivo. Furthermore, reduction of residual Mmp11 in laminin mutants promotes a Fn-rich MTJ that partially rescues skeletal muscle architecture. These results identify a mechanism for Fn downregulation at the MTJ, highlight crosstalk between laminin and Fn, and identify a new in vivo function for Mmp11. Taken together, our data demonstrate a novel signaling pathway mediating Fn downregulation. Our data revealing new regulatory mechanisms that guide ECM remodeling during morphogenesis in vivo may inform pathological conditions in which Fn is dysregulated.
FINITE RIODAN MATRIX AND RIODAN GROUP
Institute of Scientific and Technical Information of China (English)
2000-01-01
Riodan Matrix is a lower triangular matrix of in finite order with certainly restricted conditions.In this paper,the author defines two kinds of finite Riodan matrices which are not limited to lower triangular.Properties of group theory of the two kinds matrices are considered.Applications of the finite Riodan matrices are researched.
The Matrix exponential, Dynamic Systems and Control
DEFF Research Database (Denmark)
Poulsen, Niels Kjølstad
2004-01-01
The matrix exponential can be found in various connections in analysis and control of dynamic systems. In this short note we are going to list a few examples. The matrix exponential usably pops up in connection to the sampling process, whatever it is in a deterministic or a stochastic setting...
Exploratory matrix factorization for PET image analysis.
Kodewitz, A; Keck, I R; Tomé, A M; Lang, E W
2010-01-01
Features are extracted from PET images employing exploratory matrix factorization techniques such as nonnegative matrix factorization (NMF). Appropriate features are fed into classifiers such as a support vector machine or a random forest tree classifier. An automatic feature extraction and classification is achieved with high classification rate which is robust and reliable and can help in an early diagnosis of Alzheimer's disease.
Matrix perturbations: bounding and computing eigenvalues
Reis da Silva, R.J.
2011-01-01
Despite the somewhat negative connotation of the word, not every perturbation is a bad perturbation. In fact, while disturbing the matrix entries, many perturbations still preserve useful properties such as the orthonormality of the basis of eigenvectors or the Hermicity of the original matrix. In t
Matrix subordinators and related Upsilon transformations
DEFF Research Database (Denmark)
Barndorff-Nielsen, Ole Eiler; Pérez-Abreu, V.
2008-01-01
A class of upsilon transformations of Lévy measures for matrix subordinators is introduced. Some regularizing properties of these transformations are derived, such as absolute continuity and complete monotonicity. The class of Lévy measures with completely monotone matrix densities is characterized....... Examples of infinitely divisible nonnegative definite random matrices are constructed using an upsilon transformation....
New Matrix Loop Algebra and Its Application
Institute of Scientific and Technical Information of China (English)
DONG Huan-He; XU Yue-Cai
2008-01-01
A new matrix Lie algebra and its corresponding Loop algebra are constructed firstly, as its appfication, the multi-component TC equation hierarchy is obtained, then by use of trace identity the Hamiltonian structure of the above system is presented. Finally, the integrable couplings of the obtained system is worked out by the expanding matrix Loop algebra.
The Matrix exponential, Dynamic Systems and Control
DEFF Research Database (Denmark)
Poulsen, Niels Kjølstad
2004-01-01
The matrix exponential can be found in various connections in analysis and control of dynamic systems. In this short note we are going to list a few examples. The matrix exponential usably pops up in connection to the sampling process, whatever it is in a deterministic or a stochastic setting...
Differential analysis of matrix convex functions II
DEFF Research Database (Denmark)
Hansen, Frank; Tomiyama, Jun
2009-01-01
We continue the analysis in [F. Hansen, and J. Tomiyama, Differential analysis of matrix convex functions. Linear Algebra Appl., 420:102--116, 2007] of matrix convex functions of a fixed order defined in a real interval by differential methods as opposed to the characterization in terms of divide...
The Cartan Matrix of a Centralizer Algebra
Indian Academy of Sciences (India)
Umesh V Dubey; Amritanshu Prasad; Pooja Singla
2012-02-01
The centralizer algebra of a matrix consists of those matrices that commute with it. We investigate the basic representation-theoretic invariants of centralizer algebras, namely their radicals, projective indecomposable modules, injective indecomposable modules, simple modules and Cartan matrices. With the help of our Cartan matrix calculations we determine their global dimensions. Many of these algebras are of infinite global dimension.
Finding nonoverlapping substructures of a sparse matrix
Energy Technology Data Exchange (ETDEWEB)
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.
Matrix model description of baryonic deformations
Energy Technology Data Exchange (ETDEWEB)
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.
Fragmentation of extracellular matrix by hypochlorous acid
DEFF Research Database (Denmark)
Woods, Alan A; Davies, Michael Jonathan
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)...
Modeling and Simulation of Matrix Converter
DEFF Research Database (Denmark)
Liu, Fu-rong; Klumpner, Christian; Blaabjerg, Frede
2005-01-01
This paper discusses the modeling and simulation of matrix converter. Two models of matrix converter are presented: one is based on indirect space vector modulation and the other is based on power balance equation. The basis of these two models is• given and the process on modeling is introduced...
Infinite Matrix Products and the Representation of the Matrix Gamma Function
Directory of Open Access Journals (Sweden)
J.-C. Cortés
2015-01-01
Full Text Available We introduce infinite matrix products including some of their main properties and convergence results. We apply them in order to extend to the matrix scenario the definition of the scalar gamma function given by an infinite product due to Weierstrass. A limit representation of the matrix gamma function is also provided.
Wei, Spencer C; Fattet, Laurent; Tsai, Jeff H; Guo, Yurong; Pai, Vincent H; Majeski, Hannah E; Chen, Albert C; Sah, Robert L; Taylor, Susan S; Engler, Adam J; Yang, Jing
2015-05-01
Matrix stiffness potently regulates cellular behaviour in various biological contexts. In breast tumours, the presence of dense clusters of collagen fibrils indicates increased matrix stiffness and correlates with poor survival. It is unclear how mechanical inputs are transduced into transcriptional outputs to drive tumour progression. Here we report that TWIST1 is an essential mechanomediator that promotes epithelial-mesenchymal transition (EMT) in response to increasing matrix stiffness. High matrix stiffness promotes nuclear translocation of TWIST1 by releasing TWIST1 from its cytoplasmic binding partner G3BP2. Loss of G3BP2 leads to constitutive TWIST1 nuclear localization and synergizes with increasing matrix stiffness to induce EMT and promote tumour invasion and metastasis. In human breast tumours, collagen fibre alignment, a marker of increasing matrix stiffness, and reduced expression of G3BP2 together predict poor survival. Our findings reveal a TWIST1-G3BP2 mechanotransduction pathway that responds to biomechanical signals from the tumour microenvironment to drive EMT, invasion and metastasis.
Block Hadamard measurement matrix with arbitrary dimension in compressed sensing
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.
77 FR 47820 - Invention Promoters/Promotion Firms Complaints
2012-08-10
... United States Patent and Trademark Office Invention Promoters/Promotion Firms Complaints ACTION: Proposed... concerning invention promoters and responses from the invention promoters to these complaints. An individual may submit a complaint concerning an invention promoter to the USPTO, which will forward the complaint...
Institute of Scientific and Technical Information of China (English)
杨子桧; 吴宝磊; 贾森; 杨新杰; 单春; 刘晓昌; 王磊; 雷德林
2015-01-01
BACKGROUND:Distraction osteogenesis is one of the most important tissue engineering technologies. However, the exact signaling pathway controling mesenchymal stem cel-osteoblast lineage (MSC-OB) migration during distraction osteogenesis has not yet been elucidated. More efforts should be paid to make a ful understanding of the mechanism on MSC-OB lineage migration, which can improve the clinical efficacy of distraction osteogenesis. OBJECTIVE:To evaluate the effects of mechanical stretch on the ability of MSC-OB mobility and expression of mammalian target of rapamycin (mTOR) signaling pathway as wel as matrix metaloproteinases (MMPs) in MSC-OB, and to make clear the mechanism by which controls MSC-OB migration during distraction osteogenesis. METHODS:Twelve Sprague-Dawley rats were randomized into two groups: experimental group (n=6), anin vivo rat mandibular distraction osteogenesis model was established on the right side of rats; non-stretch group (n=6), only the mandibular resection was done but with no distraction osteogenesis. Immunohistochemical staining was used to detect phosphorylated mTOR expression in new osteotylus at 15 days after operation. In addition, an in vitro cel stretch model was made in the mandibular mesenchymal stem cels from healthy Sprague-Dawley rats under resting tension force (6%, 4 hours); no distraction was done in control group. The ability of MSC-OB mobility, the expression of mTOR, Raptor, p70S6K and MMPs were evaluated using experiment methods including immunohistochemistry staining, real-time PCR and scratch assay. RESULTS AND CONCLUSION: The expression of phosphorylated mTOR in MSC-OB was upregulated in the mandibular bone calus of the stretch group than the non-stretch group (P 目的：观察牵张应力下间充质干细胞-成骨细胞系mTOR信号通路相关基因的表达以及细胞迁移能力。 方法：将12只SD大鼠随机分为2组：牵张组大鼠(n=6)进行右侧下颌骨
Perturbative analysis of gauged matrix models
Dijkgraaf, Robbert; Gukov, Sergei; Kazakov, Vladimir A.; Vafa, Cumrun
2003-08-01
We analyze perturbative aspects of gauged matrix models, including those where classically the gauge symmetry is partially broken. Ghost fields play a crucial role in the Feynman rules for these vacua. We use this formalism to elucidate the fact that nonperturbative aspects of N=1 gauge theories can be computed systematically using perturbative techniques of matrix models, even if we do not possess an exact solution for the matrix model. As examples we show how the Seiberg-Witten solution for N=2 gauge theory, the Montonen-Olive modular invariance for N=1*, and the superpotential for the Leigh-Strassler deformation of N=4 can be systematically computed in perturbation theory of the matrix model or gauge theory (even though in some of these cases an exact answer can also be obtained by summing up planar diagrams of matrix models).
Perturbative Analysis of Gauged Matrix Models
Dijkgraaf, R; Kazakov, V A; Vafa, C; Dijkgraaf, Robbert; Gukov, Sergei; Kazakov, Vladimir A.; Vafa, Cumrun
2003-01-01
We analyze perturbative aspects of gauged matrix models, including those where classically the gauge symmetry is partially broken. Ghost fields play a crucial role in the Feynman rules for these vacua. We use this formalism to elucidate the fact that non-perturbative aspects of N=1 gauge theories can be computed systematically using perturbative techniques of matrix models, even if we do not possess an exact solution for the matrix model. As examples we show how the Seiberg-Witten solution for N=2 gauge theory, the Montonen-Olive modular invariance for N=1*, and the superpotential for the Leigh-Strassler deformation of N=4 can be systematically computed in perturbation theory of the matrix model/gauge theory (even though in some of these cases the exact answer can also be obtained by summing up planar diagrams of matrix models).
Matrix Coherence and the Nystrom Method
Talwalkar, Ameet
2010-01-01
The Nystrom method is an efficient technique to speed up large-scale learning applications by generating low-rank approximations. Crucial to the performance of this technique is the assumption that a matrix can be well approximated by working exclusively with a subset of its columns. In this work we relate this assumption to the concept of matrix coherence and connect matrix coherence to the performance of the Nystrom method. Making use of related work in the compressed sensing and the matrix completion literature, we derive novel coherence-based bounds for the Nystrom method in the low-rank setting. We then present empirical results that corroborate these theoretical bounds. Finally, we present more general empirical results for the full-rank setting that convincingly demonstrate the ability of matrix coherence to measure the degree to which information can be extracted from a subset of columns.
Extracellular matrix component signaling in cancer
DEFF Research Database (Denmark)
Multhaupt, Hinke A. B.; Leitinger, Birgit; Gullberg, Donald
2016-01-01
Cell responses to the extracellular matrix depend on specific signaling events. These are important from early development, through differentiation and tissue homeostasis, immune surveillance, and disease pathogenesis. Signaling not only regulates cell adhesion cytoskeletal organization and motil...... as well as matrix constitution and protein crosslinking. Here we summarize roles of the three major matrix receptor types, with emphasis on how they function in tumor progression. [on SciFinder(R)]......Cell responses to the extracellular matrix depend on specific signaling events. These are important from early development, through differentiation and tissue homeostasis, immune surveillance, and disease pathogenesis. Signaling not only regulates cell adhesion cytoskeletal organization...... and motility but also provides survival and proliferation cues. The major classes of cell surface receptors for matrix macromols. are the integrins, discoidin domain receptors, and transmembrane proteoglycans such as syndecans and CD44. Cells respond not only to specific ligands, such as collagen, fibronectin...
Spectral clustering based on matrix perturbation theory
Institute of Scientific and Technical Information of China (English)
TIAN Zheng; LI XiaoBin; JU YanWei
2007-01-01
This paper exposes some intrinsic characteristics of the spectral clustering method by using the tools from the matrix perturbation theory. We construct a weight matrix of a graph and study its eigenvalues and eigenvectors. It shows that the number of clusters is equal to the number of eigenvalues that are larger than 1, and the number of points in each of the clusters can be approximated by the associated eigenvalue. It also shows that the eigenvector of the weight matrix can be used directly to perform clustering; that is, the directional angle between the two-row vectors of the matrix derived from the eigenvectors is a suitable distance measure for clustering. As a result, an unsupervised spectral clustering algorithm based on weight matrix (USCAWM) is developed. The experimental results on a number of artificial and real-world data sets show the correctness of the theoretical analysis.
Confocal microscopy imaging of the biofilm matrix.
Schlafer, Sebastian; Meyer, Rikke L
2017-07-01
The extracellular matrix is an integral part of microbial biofilms and an important field of research. Confocal laser scanning microscopy is a valuable tool for the study of biofilms, and in particular of the biofilm matrix, as it allows real-time visualization of fully hydrated, living specimens. Confocal microscopes are held by many research groups, and a number of methods for qualitative and quantitative imaging of the matrix have emerged in recent years. This review provides an overview and a critical discussion of techniques used to visualize different matrix compounds, to determine the concentration of solutes and the diffusive properties of the biofilm matrix. Copyright © 2016 Elsevier B.V. All rights reserved.
Directory of Open Access Journals (Sweden)
Futa Yuichi
2015-03-01
Full Text Available In this article, we formalize a matrix of ℤ-module and its properties. Specially, we formalize a matrix of a linear transformation of ℤ-module, a bilinear form and a matrix of the bilinear form (Gramian matrix. We formally prove that for a finite-rank free ℤ-module V, determinant of its Gramian matrix is constant regardless of selection of its basis. ℤ-module is necessary for lattice problems, LLL (Lenstra, Lenstra and Lovász base reduction algorithm and cryptographic systems with lattices [22] and coding theory [14]. Some theorems in this article are described by translating theorems in [24], [26] and [19] into theorems of ℤ-module.
Tunable transport mean free path of light in xerogel matrixes embedded with polystyrene spheres
Bret, B P J; Amaro, M; Nunes-Pereira, E J; Belsley, M
2008-01-01
Xerogel matrices, made by sol-gel techniques, are embedded with polystyrene spheres to promote multiple scattering of light. Varying the concentration of the spheres inside the matrix allows one to adjust the transport mean free path of light inside the material. Coherent backscattering measurements show that a range of transport mean free paths from 90 to 600 nm is easily achieved. The determination of the matrix refractive index permits a direct comparison to multiple scattering and Mie theory. Such tunable diffusive sol-gel samples can be further optimized as random laser materials.
Matrix Metalloproteinases: The Gene Expression Signatures of Head and Neck Cancer Progression
Energy Technology Data Exchange (ETDEWEB)
Iizuka, Shinji [Sanford-Burnham Medical Research Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037 (United States); Ishimaru, Naozumi; Kudo, Yasusei, E-mail: yasusei@tokushima-u.ac.jp [Department of Oral Molecular Pathology, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-8-15 Kuramoto, Tokushima 770-8504 (Japan)
2014-02-13
Extracellular matrix degradation by matrix metalloproteinases (MMPs) plays a pivotal role in cancer progression by promoting motility, invasion and angiogenesis. Studies have shown that MMP expression is increased in head and neck squamous cell carcinomas (HNSCCs), one of the most common cancers in the world, and contributes to poor outcome. In this review, we examine the expression pattern of MMPs in HNSCC by microarray datasets and summarize the current knowledge of MMPs, specifically MMP-1, -3, -7 -10, -12, -13, 14 and -19, that are highly expressed in HNSCCs and involved cancer invasion and angiogenesis.
Directory of Open Access Journals (Sweden)
N. FATCHURROHMAN
2012-04-01
Full Text Available In this research solidification characteristic of metal matrix composites consisted of titanium carbide particulate reinforced aluminium-11.8% silicon alloy matrix is performed. Vortex mixing and permanent casting method are used as the manufacturing method to produce the specimens. Temperature measurements during the casting process are captured and solidification graphs are plotted to represent the solidification characteristic. The results show, as volume fraction of particulate reinforcement is increased, solidification time is faster. Particulate reinforcement promotes rapid solidification which will support finer grain size of the casting specimen. Hardness test is performed and confirmed that hardness number increased as more particulate are added to the system.
Extracellular Matrix Ligand and Stiffness Modulate Immature Nucleus Pulposus Cell-Cell Interactions
Gilchrist, Christopher L.; Darling, Eric M.; Chen, Jun; Setton, Lori A.
2011-01-01
The nucleus pulposus (NP) of the intervertebral disc functions to provide compressive load support in the spine, and contains cells that play a critical role in the generation and maintenance of this tissue. The NP cell population undergoes significant morphological and phenotypic changes during maturation and aging, transitioning from large, vacuolated immature cells arranged in cell clusters to a sparse population of smaller, isolated chondrocyte-like cells. These morphological and organizational changes appear to correlate with the first signs of degenerative changes within the intervertebral disc. The extracellular matrix of the immature NP is a soft, gelatinous material containing multiple laminin isoforms, features that are unique to the NP relative to other regions of the disc and that change with aging and degeneration. Based on this knowledge, we hypothesized that a soft, laminin-rich extracellular matrix environment would promote NP cell-cell interactions and phenotypes similar to those found in immature NP tissues. NP cells were isolated from porcine intervertebral discs and cultured in matrix environments of varying mechanical stiffness that were functionalized with various matrix ligands; cellular responses to periods of culture were assessed using quantitative measures of cell organization and phenotype. Results show that soft (<720 Pa), laminin-containing extracellular matrix substrates promote NP cell morphologies, cell-cell interactions, and proteoglycan production in vitro, and that this behavior is dependent upon both extracellular matrix ligand and substrate mechanical properties. These findings indicate that NP cell organization and phenotype may be highly sensitive to their surrounding extracellular matrix environment. PMID:22087260
Extracellular matrix ligand and stiffness modulate immature nucleus pulposus cell-cell interactions.
Directory of Open Access Journals (Sweden)
Christopher L Gilchrist
Full Text Available The nucleus pulposus (NP of the intervertebral disc functions to provide compressive load support in the spine, and contains cells that play a critical role in the generation and maintenance of this tissue. The NP cell population undergoes significant morphological and phenotypic changes during maturation and aging, transitioning from large, vacuolated immature cells arranged in cell clusters to a sparse population of smaller, isolated chondrocyte-like cells. These morphological and organizational changes appear to correlate with the first signs of degenerative changes within the intervertebral disc. The extracellular matrix of the immature NP is a soft, gelatinous material containing multiple laminin isoforms, features that are unique to the NP relative to other regions of the disc and that change with aging and degeneration. Based on this knowledge, we hypothesized that a soft, laminin-rich extracellular matrix environment would promote NP cell-cell interactions and phenotypes similar to those found in immature NP tissues. NP cells were isolated from porcine intervertebral discs and cultured in matrix environments of varying mechanical stiffness that were functionalized with various matrix ligands; cellular responses to periods of culture were assessed using quantitative measures of cell organization and phenotype. Results show that soft (<720 Pa, laminin-containing extracellular matrix substrates promote NP cell morphologies, cell-cell interactions, and proteoglycan production in vitro, and that this behavior is dependent upon both extracellular matrix ligand and substrate mechanical properties. These findings indicate that NP cell organization and phenotype may be highly sensitive to their surrounding extracellular matrix environment.
Differential regulation of dentin matrix protein 1 expression during odontogenesis.
Lu, Yongbo; Zhang, Shubin; Xie, Yixia; Pi, Yuli; Feng, Jian Q
2005-01-01
Dentin matrix protein 1 (DMP1) is highly expressed in mineralized tooth and bone. Both in vitro and in vivo data show that DMP1 is critical for mineralization and tooth morphogenesis (growth and development). In this study, we studied Dmp1 gene regulation. The in vitro transient transfection assay identified two important DNA fragments, the 2.4- and 9.6-kb promoter regions. We next generated and analyzed transgenic mice bearing the beta-galactosidase (lacZ) reporter gene driven by the 2.4- or 9.6-kb promoter with the complete 4-kb intron 1. The 9.6-kb Dmp1-lacZ mice conferred a DMP1 expression pattern in odontoblasts identical to that in the endogenous Dmp1 gene. This is reflected by lacZ expression in Dmp1-lacZ knock-in mice during all stages of odontogenesis. In contrast, the 2.4-kb Dmp1-lacZ mice display activity in odontoblast cells only at the early stage of odontogenesis. Thus, we propose that different transcription factors regulate early or later cis-regulatory domains of the Dmp1 promoter, which gives rise to the unique spatial and temporal expression pattern of Dmp1 gene at different stages of tooth development. 2005 S. Karger AG, Basel
Promoting Renewable Energy Technologies
DEFF Research Database (Denmark)
Olsen, Ole Jess; Skytte, Klaus
% of its annual electricity production. In this paper, we present and discuss the Danish experience as a case of promoting renewable energy technologies. The development path of the two technologies has been very different. Wind power is considered an outright success with fast deployment to decreasing...... technology and its particular context, it is possible to formulate some general principles that can help to create an effective and efficient policy for promoting new renewable energy technologies....
Promoting Renewable Energy Technologies
DEFF Research Database (Denmark)
Olsen, Ole Jess; Skytte, Klaus
% of its annual electricity production. In this paper, we present and discuss the Danish experience as a case of promoting renewable energy technologies. The development path of the two technologies has been very different. Wind power is considered an outright success with fast deployment to decreasing...... technology and its particular context, it is possible to formulate some general principles that can help to create an effective and efficient policy for promoting new renewable energy technologies....
DEFF Research Database (Denmark)
Visholm, Steen
PRESENTATION No 72 Steen Visholm Associate professor, M.Psych., Ph. D., Roskilde University Private adress: Krystalgade 6 II DK-1172 København K Denmark svisholm@ruc.dk THE PROMOTED SIBLING By their writings about sibling relations Mitchell and Coles has added fruitful complexity to the psychodyn......PRESENTATION No 72 Steen Visholm Associate professor, M.Psych., Ph. D., Roskilde University Private adress: Krystalgade 6 II DK-1172 København K Denmark svisholm@ruc.dk THE PROMOTED SIBLING By their writings about sibling relations Mitchell and Coles has added fruitful complexity...... to the psychodynamic understanding of families, groups and organisations. With a point of departure in a study of self-governing groups in a factory the paper introduces the concept: ‘the promoted sibling’ which provide quite some understanding of the middle managers challenges in his or her role and the challenges...... in democracy in general. The middle manager can be seen as ‘a sibling promoted from above’ and democracy can be seen as siblings promoting a sibling to be ‘a temporary parent’ (Winnicott) or ‘a sibling promoted from below’. The extension of the family dynamics with the sibling relations provides a way...
Origins of replication and the nuclear matrix: the DHFR domain as a paradigm.
Dijkwel, P A; Hamlin, J L
1995-01-01
The eukaryotic genome appears to be organized in a loopwise fashion by periodic attachment to the nuclear matrix. The proposal that a chromatin loop corresponds to a functional domain has stirred interest in the properties of the DNA sequences at the bases of these loops, the matrix-attached regions (MARs). Evidence has been presented suggesting that certain MARs act as boundary elements isolating domains from their chromosomal context. MARs have also been found in the vicinity of promoters and enhancers and they could act by displacing these cis-regulatory elements into the proper nuclear subcompartment. Attachment to the matrix might also play a role in DNA replication. A large body of evidence indicates that replication occurs on the nuclear matrix. This implies that any DNA sequence will be attached to the matrix at a certain time during the cell cycle. This transient mode of attachment contrasts with the proposed permanent attachment of origins of DNA replication with the nuclear matrix. While some data exist that support this suggestion, the current lack of understanding of the mammalian replication origin precludes definitive conclusions regarding the role of MARs in the initiation process.
[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.
Decellularized bone matrix grafts for calvaria regeneration
Lee, Dong Joon; Diachina, Shannon; Lee, Yan Ting; Zhao, Lixing; Zou, Rui; Tang, Na; Han, Han; Chen, Xin; Ko, Ching-Chang
2016-01-01
Decellularization is a promising new method to prepare natural matrices for tissue regeneration. Successful decellularization has been reported using various tissues including skin, tendon, and cartilage, though studies using hard tissue such as bone are lacking. In this study, we aimed to define the optimal experimental parameters to decellularize natural bone matrix using 0.5% sodium dodecyl sulfate and 0.1% NH4OH. Then, the effects of decellularized bone matrix on rat mesenchymal stem cell proliferation, osteogenic gene expression, and osteogenic differentiations in a two-dimensional culture system were investigated. Decellularized bone was also evaluated with regard to cytotoxicity, biochemical, and mechanical characteristics in vitro. Evidence of complete decellularization was shown through hematoxylin and eosin staining and DNA measurements. Decellularized bone matrix displayed a cytocompatible property, conserved structure, mechanical strength, and mineral content comparable to natural bone. To study new bone formation, implantation of decellularized bone matrix particles seeded with rat mesenchymal stem cells was conducted using an orthotopic in vivo model. After 3 months post-implantation into a critical-sized defect in rat calvaria, new bone was formed around decellularized bone matrix particles and also merged with new bone between decellularized bone matrix particles. New bone formation was analyzed with micro computed tomography, mineral apposition rate, and histomorphometry. Decellularized bone matrix stimulated mesenchymal stem cell proliferation and osteogenic differentiation in vitro and in vivo, achieving effective bone regeneration and thereby serving as a promising biological bone graft. PMID:28228929
Decellularized bone matrix grafts for calvaria regeneration
Directory of Open Access Journals (Sweden)
Dong Joon Lee
2016-12-01
Full Text Available Decellularization is a promising new method to prepare natural matrices for tissue regeneration. Successful decellularization has been reported using various tissues including skin, tendon, and cartilage, though studies using hard tissue such as bone are lacking. In this study, we aimed to define the optimal experimental parameters to decellularize natural bone matrix using 0.5% sodium dodecyl sulfate and 0.1% NH4OH. Then, the effects of decellularized bone matrix on rat mesenchymal stem cell proliferation, osteogenic gene expression, and osteogenic differentiations in a two-dimensional culture system were investigated. Decellularized bone was also evaluated with regard to cytotoxicity, biochemical, and mechanical characteristics in vitro. Evidence of complete decellularization was shown through hematoxylin and eosin staining and DNA measurements. Decellularized bone matrix displayed a cytocompatible property, conserved structure, mechanical strength, and mineral content comparable to natural bone. To study new bone formation, implantation of decellularized bone matrix particles seeded with rat mesenchymal stem cells was conducted using an orthotopic in vivo model. After 3 months post-implantation into a critical-sized defect in rat calvaria, new bone was formed around decellularized bone matrix particles and also merged with new bone between decellularized bone matrix particles. New bone formation was analyzed with micro computed tomography, mineral apposition rate, and histomorphometry. Decellularized bone matrix stimulated mesenchymal stem cell proliferation and osteogenic differentiation in vitro and in vivo, achieving effective bone regeneration and thereby serving as a promising biological bone graft.
Residual, restarting and Richardson iteration for the matrix exponential
Botchev, M.A.
2010-01-01
A well-known problem in computing some matrix functions iteratively is a lack of a clear, commonly accepted residual notion. An important matrix function for which this is the case is the matrix exponential. Assume, the matrix exponential of a given matrix times a given vector has to be computed.
Residual, restarting and Richardson iteration for the matrix exponential
Botchev, Mike A.; Grimm, Volker; Hochbruck, Marlis
2013-01-01
A well-known problem in computing some matrix functions iteratively is the lack of a clear, commonly accepted residual notion. An important matrix function for which this is the case is the matrix exponential. Suppose the matrix exponential of a given matrix times a given vector has to be computed.
Neutrino masses from an approximate mixing matrix with $\\theta_{13}\
Damanik, Asan
2016-01-01
An approximate neutrino mixing matrix is formutated by using the standard neutrino mixing matrix as a basis and experimental data of neutrino oscillations as inputs. By using the resulted approximate neutrino mixing matrix to proceed the neutrino mass matrix and constraining the resulted neutrino mass matrix with zero texture: $M_{\
Conservation of Supergravity Currents from Matrix Theory
Van Raamsdonk, M
1999-01-01
In recent work by Kabat and Taylor, certain Matrix theory quantities have been identified with the spatial moments of the supergravity stress-energy tensor, membrane current, and fivebrane current. In this note, we determine the relations between these moments required by current conservation, and prove that these relations hold as exact Matrix Theory identities at finite N. This establishes conservation of the effective supergravity currents (averaged over the compact circle). In addition, the constraints of current conservation allow us to deduce Matrix theory quantities corresponding to moments of the spatial current of the longitudinal fivebrane charge, not previously identified.
Formalization of Matrix Theory in HOL4
Directory of Open Access Journals (Sweden)
Zhiping Shi
2014-08-01
Full Text Available Matrix theory plays an important role in modeling linear systems in engineering and science. To model and analyze the intricate behavior of complex systems, it is imperative to formalize matrix theory in a metalogic setting. This paper presents the higher-order logic (HOL formalization of the vector space and matrix theory in the HOL4 theorem proving system. Formalized theories include formal definitions of real vectors and matrices, algebraic properties, and determinants, which are verified in HOL4. Two case studies, modeling and verifying composite two-port networks and state transfer equations, are presented to demonstrate the applicability and effectiveness of our work.
Generic construction of efficient matrix product operators
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.
A matrix model from string field theory
Directory of Open Access Journals (Sweden)
Syoji Zeze
2016-09-01
Full Text Available 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.
Partial chord diagrams and matrix models
DEFF Research Database (Denmark)
Andersen, Jørgen Ellegaard; Fuji, Hiroyuki; Manabe, Masahide
spectrum. Furthermore, we consider the boundary length and point spectrum that unifies the last two types of spectra. We introduce matrix models that encode generating functions of partial chord diagrams filtered by each of these spectra. Using these matrix models, we derive partial differential equations......In this article, the enumeration of partial chord diagrams is discussed via matrix model techniques. In addition to the basic data such as the number of backbones and chords, we also consider the Euler characteristic, the backbone spectrum, the boundary point spectrum, and the boundary length...... – obtained independently by cut-and-join arguments in an earlier work – for the corresponding generating functions....
A transilient matrix for moist convection
Energy Technology Data Exchange (ETDEWEB)
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.
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.
Visual Matrix Clustering of Social Networks
Energy Technology Data Exchange (ETDEWEB)
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.
Efficient matrix inversion based on VLIW architecture
Institute of Scientific and Technical Information of China (English)
Li Zhang,Fu Li,; Guangming Shi
2014-01-01
Matrix inversion is a critical part in communication, signal processing and electromagnetic system. A flexible and scal-able very long instruction word (VLIW) processor with clustered architecture is proposed for matrix inversion. A global register file (RF) is used to connect al the clusters. Two nearby clusters share a local register file. The instruction sets are also designed for the VLIW processor. Experimental results show that the proposed VLIW architecture takes only 45 latency to invert a 4 × 4 matrix when running at 150 MHz. The proposed design is roughly five times faster than the DSP solution in processing speed.
Generalized companion matrix for approximate GCD
Boito, Paola
2011-01-01
We study a variant of the univariate approximate GCD problem, where the coe?- cients of one polynomial f(x)are known exactly, whereas the coe?cients of the second polynomial g(x)may be perturbed. Our approach relies on the properties of the matrix which describes the operator of multiplication by gin the quotient ring C[x]=(f). In particular, the structure of the null space of the multiplication matrix contains all the essential information about GCD(f; g). Moreover, the multiplication matrix exhibits a displacement structure that allows us to design a fast algorithm for approximate GCD computation with quadratic complexity w.r.t. polynomial degrees.
A matrix model from string field theory
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.
Three-Algebra Bfss Matrix Theory
Sato, Matsuo
2013-11-01
We extend the BFSS matrix theory by means of Lie 3-algebra. The extended model possesses the same supersymmetry as the original BFSS matrix theory, and thus as the infinite momentum frame limit of M-theory. We study dynamics of the model by choosing the minimal Lie 3-algebra that includes u(N) algebra. We can solve a constraint in the minimal model and obtain two phases. In one phase, the model reduces to the original matrix model. In another phase, it reduces to a simple supersymmetric model.
Three-Algebra BFSS Matrix Theory
Sato, Matsuo
2013-01-01
We extend the BFSS matrix theory by means of Lie 3-algebra. The extended model possesses the same supersymmetry as the original BFSS matrix theory, and thus as the infinite momentum frame limit of M-theory. We study dynamics of the model by choosing the minimal Lie 3-algebra that includes u(N) algebra. We can solve a constraint in the minimal model and obtain two phases. In one phase, the model reduces to the original matrix model. In another phase, it reduces to a simple supersymmetric model.
Embedded systems for controlling LED matrix displays
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.
Matrix Strings, Compactification Scales and Hagedorn Transition
Meana, M L; Meana, Marco Laucelli; Peñalba, Jesús Puente
1999-01-01
In this work we use the Matrix Model of Strings in order to extract some non-perturbative information on how the Hagedorn critical temperature arises from eleven-dimensional physics. We study the thermal behavior of M and Matrix theories on the compactification backgrounds that correspond to string models. We obtain some information that allows us to state that the Hagedorn temperature is not unique for all Matrix String models and we are also able to sketch how the $S$-duality transformation works in this framework.
CDENPROP: Transition matrix elements involving continuum states
Harvey, Alex G; Morales, Felipe; Smirnova, Olga
2014-01-01
Transition matrix elements between electronic states where one electron can be in the continuum are required for a wide range of applications of the molecular R-matrix method. These include photoionization, photorecombination and photodetachment; electron-molecule scattering and photon-induced processes in the presence of an external D.C. field, and time-dependent R-matrix approaches to study the effect of the exposure of molecules to strong laser fields. We present a new algorithm, implemented as a module (CDENPROP) in the UKRmol electron-molecule scattering code suite.
Invisible data matrix detection with smart phone using geometric correction and Hough transform
Sun, Halit; Uysalturk, Mahir C.; Karakaya, Mahmut
2016-04-01
Two-dimensional data matrices are used in many different areas that provide quick and automatic data entry to the computer system. Their most common usage is to automatically read labeled products (books, medicines, food, etc.) and recognize them. In Turkey, alcohol beverages and tobacco products are labeled and tracked with the invisible data matrices for public safety and tax purposes. In this application, since data matrixes are printed on a special paper with a pigmented ink, it cannot be seen under daylight. When red LEDs are utilized for illumination and reflected light is filtered, invisible data matrices become visible and decoded by special barcode readers. Owing to their physical dimensions, price and requirement of special training to use; cheap, small sized and easily carried domestic mobile invisible data matrix reader systems are required to be delivered to every inspector in the law enforcement units. In this paper, we first developed an apparatus attached to the smartphone including a red LED light and a high pass filter. Then, we promoted an algorithm to process captured images by smartphones and to decode all information stored in the invisible data matrix images. The proposed algorithm mainly involves four stages. In the first step, data matrix code is processed by Hough transform processing to find "L" shaped pattern. In the second step, borders of the data matrix are found by using the convex hull and corner detection methods. Afterwards, distortion of invisible data matrix corrected by geometric correction technique and the size of every module is fixed in rectangular shape. Finally, the invisible data matrix is scanned line by line in the horizontal axis to decode it. Based on the results obtained from the real test images of invisible data matrix captured with a smartphone, the proposed algorithm indicates high accuracy and low error rate.
Comix, a New Matrix Element Generator
Energy Technology Data Exchange (ETDEWEB)
Gleisberg, Tanju; /SLAC; 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.
A Matrix Construction of Cellular Algebras
Institute of Scientific and Technical Information of China (English)
Dajing Xiang
2005-01-01
In this paper, we give a concrete method to construct cellular algebras from matrix algebras by specifying certain fixed matrices for the data of inflations. In particular,orthogonal matrices can be chosen for such data.
Matrix-exponential distributions in applied probability
Bladt, Mogens
2017-01-01
This book contains an in-depth treatment of matrix-exponential (ME) distributions and their sub-class of phase-type (PH) distributions. Loosely speaking, an ME distribution is obtained through replacing the intensity parameter in an exponential distribution by a matrix. The ME distributions can also be identified as the class of non-negative distributions with rational Laplace transforms. If the matrix has the structure of a sub-intensity matrix for a Markov jump process we obtain a PH distribution which allows for nice probabilistic interpretations facilitating the derivation of exact solutions and closed form formulas. The full potential of ME and PH unfolds in their use in stochastic modelling. Several chapters on generic applications, like renewal theory, random walks and regenerative processes, are included together with some specific examples from queueing theory and insurance risk. We emphasize our intention towards applications by including an extensive treatment on statistical methods for PH distribu...
GB Diet matrix as informed by EMAX
National Oceanic and Atmospheric Administration, Department of Commerce — This data set was taken from CRD 08-18 at the NEFSC. Specifically, the Georges Bank diet matrix was developed for the EMAX exercise described in that center...
CERN. Geneva
2016-01-01
In this talk I will describe recent work aiming to reinvigorate the 50 year old S-matrix program, which aims to constrain scattering of massive particles non-perturbatively. I will begin by considering quantum fields in anti-de Sitter space and show that one can extract information about the S-matrix by considering correlators in conformally invariant theories. The latter can be studied with "bootstrap" techniques, which allow us to constrain the S-matrix. In particular, in 1+1D one obtains bounds which are saturated by known integrable models. I will also show that it is also possible to directly constrain the S-matrix, without using the CFT crutch, by using crossing symmetry and unitarity. This alternative method is simpler and gives results in agreement with the previous approach. Both techniques are generalizable to higher dimensions.
A matrix of social accounting for Asturias
Directory of Open Access Journals (Sweden)
Margarita Argüelles
2003-01-01
Full Text Available A Social Accounting Matrix is an integrated system of accounts that presents in a double-entry table all the transactions made in an economy among productive sectors, production factors, institutional sectors and the rest of the world. In comparison with an Input-Output Table, it offers a greater deal of information and shows completely the circular process of income, captivating more precisely the effects of exogenous changes. One of the main profits of a Social Accounting Matrix is to serve as a database for the development and application of a computable general equilibrium model. This is, in fact, the aim pursued with the elaboration of the Social Accounting Matrix for the Asturian economy presented here. This Matrix has been constructed with data from the 1995 Regional Accounts of Asturias, and its structure has been adapted to its future use as a database for a computable general equilibrium model of this regional economy.
Material parameter identification on metal matrix composites
CSIR Research Space (South Africa)
Jansen van Rensburg, GJ
2012-07-01
Full Text Available Tests were done on the compressive behaviour of different metal matrix composite materials. These extremely hard engineering materials consist of ceramic particles embedded in a metal alloy binder. Due to the high stiffness and brittle nature...
Energy Technology Data Exchange (ETDEWEB)
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.
Energy Technology Data Exchange (ETDEWEB)
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.
Preparation and Characterization of Sustained Release Matrix ...
African Journals Online (AJOL)
Tropical Journal of Pharmaceutical Research October 2015; 14(10): 1749-1754 ... prolonged drug release and improvement in motor activity after spinal injuries. Methods: Matrix .... The friability test was performed using a Roche friabilator ...
Sensitivity analysis of periodic matrix population models.
Caswell, Hal; Shyu, Esther
2012-12-01
Periodic matrix models are frequently used to describe cyclic temporal variation (seasonal or interannual) and to account for the operation of multiple processes (e.g., demography and dispersal) within a single projection interval. In either case, the models take the form of periodic matrix products. The perturbation analysis of periodic models must trace the effects of parameter changes, at each phase of the cycle, on output variables that are calculated over the entire cycle. Here, we apply matrix calculus to obtain the sensitivity and elasticity of scalar-, vector-, or matrix-valued output variables. We apply the method to linear models for periodic environments (including seasonal harvest models), to vec-permutation models in which individuals are classified by multiple criteria, and to nonlinear models including both immediate and delayed density dependence. The results can be used to evaluate management strategies and to study selection gradients in periodic environments.
Emergent spacetime & quantum entanglement in matrix theory
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.
Interacting Giant Gravitons from Spin Matrix Theory
Harmark, Troels
2016-01-01
Using the non-abelian DBI action we find an effective matrix model that describes the dynamics of weakly interacting giant gravitons wrapped on three-spheres in the AdS part of AdS_5 x S^5 at high energies with two angular momenta on the S^5. In parallel we consider the limit of \\CN=4 super Yang-Mills theory near a certain unitarity bound where it reduces to the quantum mechanical theory called SU(2) Spin Matrix Theory. We show that the exact same matrix model that describes the giant gravitons on the string theory side also provides the effective description in the strong coupling and large energy limit of the Spin Matrix Theory. Thus, we are able to match non-supersymmetric dynamics of D-branes on AdS_5 x S^5 to a finite-N regime in \\CN=4 super Yang-Mills theory near a unitarity bound.
Matrix Graph Grammars with Application Conditions
Velasco, Pedro Pablo Perez
2009-01-01
In the Matrix approach to graph transformation we represent simple digraphs and rules with Boolean matrices and vectors, and the rewriting is expressed using Boolean operators only. In previous works, we developed analysis techniques that allow studying the applicability of rule sequences, their independence, state reachability and the minimal graph able to fire a sequence. In the present paper we improve our framework in two ways. First, we make explicit (in the form of a Boolean matrix) some negative implicit information in rules. This matrix (called "nihilation matrix") contains the elements that if present, forbid the application of the rule (i.e. potential dangling edges, or newly added edges, which cannot be already present in the simple digraph). Second, we introduce a novel notion of application condition, which combines graph diagrams together with monadic second order logic. This allows more flexibility and expressivity than previous approaches, as well as more concise conditions in certain cases. W...
Matrix Models, Monopoles and Modified Moduli
Erlich, J; Unsal, M; Erlich, Joshua; Hong, Sungho; Unsal, Mithat
2004-01-01
Motivated by the Dijkgraaf-Vafa correspondence, we consider the matrix model duals of N=1 supersymmetric SU(Nc) gauge theories with Nf flavors. We demonstrate via the matrix model solutions a relation between vacua of theories with different numbers of colors and flavors. This relation is due to an N=2 nonrenormalization theorem which is inherited by these N=1 theories. Specializing to the case Nf=Nc, the simplest theory containing baryons, we demonstrate that the explicit matrix model predictions for the locations on the Coulomb branch at which monopoles condense are consistent with the quantum modified constraints on the moduli in the theory. The matrix model solutions include the case that baryons obtain vacuum expectation values. In specific cases we check explicitly that these results are also consistent with the factorization of corresponding Seiberg-Witten curves. Certain results are easily understood in terms of M5-brane constructions of these gauge theories.
Matrix Models, Monopoles and Modified Moduli
Erlich, Joshua; Hong, Sungho; Unsal, Mithat
2004-09-01
Motivated by the Dijkgraaf-Vafa correspondence, we consider the matrix model duals of Script N = 1 supersymmetric SU(Nc) gauge theories with Nf flavors. We demonstrate via the matrix model solutions a relation between vacua of theories with different numbers of colors and flavors. This relation is due to an Script N = 2 nonrenormalization theorem which is inherited by these Script N = 1 theories. Specializing to the case Nf = Nc, the simplest theory containing baryons, we demonstrate that the explicit matrix model predictions for the locations on the Coulomb branch at which monopoles condense are consistent with the quantum modified constraints on the moduli in the theory. The matrix model solutions include the case that baryons obtain vacuum expectation values. In specific cases we check explicitly that these results are also consistent with the factorization of corresponding Seiberg-Witten curves. Certain results are easily understood in terms of M5-brane constructions of these gauge theories.
Microwave Processed Multifunctional Polymer Matrix Composites Project
National Aeronautics and Space Administration — NASA has identified polymer matrix composites (PMCs) as a critical need for launch and in-space vehicles, but the significant costs of such materials limits their...
Interfaces between a fibre and its matrix
DEFF Research Database (Denmark)
Lilholt, Hans; Sørensen, Bent F.
2017-01-01
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...... 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....
Targeting the extracellular matrix to disrupt cancer progression
Directory of Open Access Journals (Sweden)
Freja Albjerg Venning
2015-10-01
Full Text Available Metastatic complications are responsible for more than 90% of cancer related deaths. The progression from an isolated tumor to disseminated metastatic disease is a multi-step process, with each step involving intricate cross-talk between the cancer cells and their non-cellular surroundings, the extracellular matrix (ECM. Many ECM proteins are significantly de-regulated during the progression of cancer, causing both biochemical and biomechanical changes that together promote the metastatic cascade. In this review, the influence of several ECM proteins on these multiple steps of cancer spread is summarized. In addition, we highlight the promising (pre-clinical data showing benefits of targeting these ECM macromolecules to prevent cancer progression.
Improving Employee Satisfaction Priority through Performance Control Matrix
Directory of Open Access Journals (Sweden)
Shun-Hsing Chen
2014-11-01
Full Text Available The study addresses Performance Control Matrix (PCM to determine service quality items of priority for improvement. Most businesses focus on customer satisfaction when undertaking surveys of satisfaction and dissatisfaction, while generally neglecting employee satisfaction. Therefore, this study develops an integrated model to improve service quality in Taiwanese finance industry employees. A questionnaire is designed to determine the priority of improvement objectives derived from certain questionnaire items that fall into the improvement zone of the PCM. Ten items are found to fall into the improvement zone of the PCM. The present results show that the finance industry employees surveyed in Taiwan were dissatisfied with their job security, salaries, annual bonus, and fair distribution of operational profits. The ten improvement items mostly belong to two dimensions - ‘Pay and Benefits’ and ‘Motivation’. The managers of the financial institutions should seek to improve these quality attributes by devoting more resources to these items, thus promoting employee satisfaction.
Matrix population models from 20 studies of perennial plant populations
Ellis, Martha M.; Williams, Jennifer L.; Lesica, Peter; Bell, Timothy J.; Bierzychudek, Paulette; Bowles, Marlin; Crone, Elizabeth E.; Doak, Daniel F.; Ehrlen, Johan; Ellis-Adam, Albertine; McEachern, Kathryn; Ganesan, Rengaian; Latham, Penelope; Luijten, Sheila; Kaye, Thomas N.; Knight, Tiffany M.; Menges, Eric S.; Morris, William F.; den Nijs, Hans; Oostermeijer, Gerard; Quintana-Ascencio, Pedro F.; Shelly, J. Stephen; Stanley, Amanda; Thorpe, Andrea; Tamara, Ticktin; Valverde, Teresa; Weekley, Carl W.
2012-01-01
Demographic transition matrices are one of the most commonly applied population models for both basic and applied ecological research. The relatively simple framework of these models and simple, easily interpretable summary statistics they produce have prompted the wide use of these models across an exceptionally broad range of taxa. Here, we provide annual transition matrices and observed stage structures/population sizes for 20 perennial plant species which have been the focal species for long-term demographic monitoring. These data were assembled as part of the 'Testing Matrix Models' working group through the National Center for Ecological Analysis and Synthesis (NCEAS). In sum, these data represent 82 populations with >460 total population-years of data. It is our hope that making these data available will help promote and improve our ability to monitor and understand plant population dynamics.
Computing a Nonnegative Matrix Factorization -- Provably
Arora, Sanjeev; Kannan, Ravi; Moitra, Ankur
2011-01-01
In the Nonnegative Matrix Factorization (NMF) problem we are given an $n \\times m$ nonnegative matrix $M$ and an integer $r > 0$. Our goal is to express $M$ as $A W$ where $A$ and $W$ are nonnegative matrices of size $n \\times r$ and $r \\times m$ respectively. In some applications, it makes sense to ask instead for the product $AW$ to approximate $M$ -- i.e. (approximately) minimize $\
On Quark Mixings and CKM Matrix
Senju, H.
1991-05-01
Inspired by unique features of the preon-subpreon model, we study quark mixings and the CKM matrix. The resultant CKM matrix has very nice properties. V_{cb} =~ - V_{ts} is predicted. Our scheme has a strong possibility to explain that V_{us} and V_{cd} are remarkably large compared with other off-diagonal elements and that V_{ub} and V_{td} are much smaller than V_{cb}.
Ubiquitination of specific mitochondrial matrix proteins
Energy Technology Data Exchange (ETDEWEB)
Lehmann, Gilad [The Janet and David Polak Tumor and Vascular Biology Research Center and the Technion Integrated Cancer Center (TICC), The Rappaport Faculty of Medicine and Research Institute, Haifa, 31096 (Israel); Ziv, Tamar [The Smoler Proteomics Center, Faculty of Biology – Technion-Israel Institute of Technology, Haifa, 32000 (Israel); Braten, Ori [The Janet and David Polak Tumor and Vascular Biology Research Center and the Technion Integrated Cancer Center (TICC), The Rappaport Faculty of Medicine and Research Institute, Haifa, 31096 (Israel); Admon, Arie [The Smoler Proteomics Center, Faculty of Biology – Technion-Israel Institute of Technology, Haifa, 32000 (Israel); Udasin, Ronald G. [The Janet and David Polak Tumor and Vascular Biology Research Center and the Technion Integrated Cancer Center (TICC), The Rappaport Faculty of Medicine and Research Institute, Haifa, 31096 (Israel); Ciechanover, Aaron, E-mail: aaroncie@tx.technion.ac.il [The Janet and David Polak Tumor and Vascular Biology Research Center and the Technion Integrated Cancer Center (TICC), The Rappaport Faculty of Medicine and Research Institute, Haifa, 31096 (Israel)
2016-06-17
Several protein quality control systems in bacteria and/or mitochondrial matrix from lower eukaryotes are absent in higher eukaryotes. These are transfer-messenger RNA (tmRNA), The N-end rule ATP-dependent protease ClpAP, and two more ATP-dependent proteases, HslUV and ClpXP (in yeast). The lost proteases resemble the 26S proteasome and the role of tmRNA and the N-end rule in eukaryotic cytosol is performed by the ubiquitin proteasome system (UPS). Therefore, we hypothesized that the UPS might have substituted these systems – at least partially – in the mitochondrial matrix of higher eukaryotes. Using three independent experimental approaches, we demonstrated the presence of ubiquitinated proteins in the matrix of isolated yeast mitochondria. First, we show that isolated mitochondria contain ubiquitin (Ub) conjugates, which remained intact after trypsin digestion. Second, we demonstrate that the mitochondrial soluble fraction contains Ub-conjugates, several of which were identified by mass spectrometry and are localized to the matrix. Third, using immunoaffinity enrichment by specific antibodies recognizing digested ubiquitinated peptides, we identified a group of Ub-modified matrix proteins. The modification was further substantiated by separation on SDS-PAGE and immunoblots. Last, we attempted to identify the ubiquitin ligase(s) involved, and identified Dma1p as a trypsin-resistant protein in our mitochondrial preparations. Taken together, these data suggest a yet undefined role for the UPS in regulation of the mitochondrial matrix proteins. -- Highlights: •Mitochondrial matrix contains ubiquitinated proteins. •Ubiquitination occurs most probably in the matrix. •Dma1p is a ubiquitin ligase present in mitochondrial preparations.
Neutrino Mass Matrix with Approximate Flavor Symmetry
Riazuddin, M
2003-01-01
Phenomenological implications of neutrino oscillations implied by recent experimental data on pattern of neutrino mass matrix are disscussed. It is shown that it is possible to have a neutrino mass matrix which shows approximate flavor symmetry; the neutrino mass differences arise from flavor violation in off-diagonal Yukawa couplings. Two modest extensions of the standard model, which can embed the resulting neutrino mass matix have also been discussed.
Correlation matrix for quartet codon usage
Frappat, L; Sorba, Paul
2005-01-01
It has been argued that the sum of usage probabilities for codons, belonging to quartets, that have as third nucleotide C or A, is independent of the biological species for vertebrates. The comparison between the theoretical correlation matrix derived from these sum rules and the experimentally computed matrix for 26 species shows a satisfactory agreement. The Shannon entropy, weakly depending on the biological species, gives further support. Suppression of codons containing the dinucleotides CG or AU is put in evidence.
Schwarzchild Black Holes in Matrix Theory, 2
Banks, T; Klebanov, Igor R; Susskind, Leonard
1998-01-01
We present a crude Matrix Theory model for Schwarzchild black holes in uncompactified dimension greater than 5. The model accounts for the size, entropy, and long range static interactions of black holes. The key feature of the model is a Boltzmann gas of D0 branes, a concept which depends on certain qualitative features of Matrix Theory which previously have not been utilized in studies of black holes.
Matrix metalloproteinases in exercise and obesity
Jaoude J; Koh Y
2016-01-01
Jonathan Jaoude,1 Yunsuk Koh2 1Department of Biology, 2Department of Health, Human Performance, and Recreation, Baylor University, Waco, TX, USA Abstract: Matrix metalloproteinases (MMPs) are zinc- and calcium-dependent endoproteinases that have the ability to break down extracellular matrix. The large range of MMPs’ functions widens their spectrum of potential role as activators or inhibitors in tissue remodeling, cardiovascular diseases, and obesity. In particular, MMP-1, -2, and ...
Recursive Array Layouts and Fast Matrix Multiplication
2005-01-01
specialized not only for a specific memory architecture but also for a specific matrix size. The ATLAS project generates code for BLAS 3 routines based on...parallel, rely on good spa- tial and temporal locality of reference for their performance. Matrix multiplication (the BLAS 3 [14] dgemm routine) is a key...multiprocessors with multi-level memory hierarchies, the column-major layout assumed in the BLAS 3 library can produce unfavorable access patterns in the memory
Polymer Matrix Composite Material Oxygen Compatibility
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.
Matrix parameters and storage conditions of manure
Energy Technology Data Exchange (ETDEWEB)
Weinfurtner, Karlheinz [Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Schmallenberg (Germany)
2011-01-15
The literature study presents an overview of storage conditions for manure and information about important matrix parameters of manure such as dry matter content, pH value, total organic carbon, total nitrogen and ammonium nitrogen. The presented results show that for matrix parameters a dissimilarity of cattle and pig manure can be observed but no difference within the species for different production types occurred with exception of calves. A scenario for western and central European countries is derived. (orig.)
Index matrices towards an augmented matrix calculus
Atanassov, Krassimir T
2014-01-01
This book presents the very concept of an index matrix and its related augmented matrix calculus in a comprehensive form. It mostly illustrates the exposition with examples related to the generalized nets and intuitionistic fuzzy sets which are examples of an extremely wide array of possible application areas. The present book contains the basic results of the author over index matrices and some of its open problems with the aim to stimulating more researchers to start working in this area.
Quantized Matrix Algebras and Quantum Seeds
DEFF Research Database (Denmark)
Jakobsen, Hans Plesner; Pagani, Chiara
2015-01-01
We determine explicitly quantum seeds for classes of quantized matrix algebras. Furthermore, we obtain results on centres and block diagonal forms of these algebras. In the case where is an arbitrary root of unity, this further determines the degrees.......We determine explicitly quantum seeds for classes of quantized matrix algebras. Furthermore, we obtain results on centres and block diagonal forms of these algebras. In the case where is an arbitrary root of unity, this further determines the degrees....
Orbifold matrix models and fuzzy extra dimensions
Chatzistavrakidis, Athanasios; Zoupanos, George
2011-01-01
We revisit an orbifold matrix model obtained as a restriction of the type IIB matrix model on a Z_3-invariant sector. An investigation of its moduli space of vacua is performed and issues related to chiral gauge theory and gravity are discussed. Modifications of the orbifolded model triggered by Chern-Simons or mass deformations are also analyzed. Certain vacua of the modified models exhibit higher-dimensional behaviour with internal geometries related to fuzzy spheres.
Matrix-valued Quantum Lattice Boltzmann Method
Mendl, Christian B
2013-01-01
We develop a numerical framework for the quantum analogue of the "classical" lattice Boltzmann method (LBM), with the Maxwell-Boltzmann distribution replaced by the Fermi-Dirac function. To accommodate the spin density matrix, the distribution functions become 2x2-matrix valued. We show that the efficient, commonly used BGK approximation of the collision operator is valid in the present setting. The framework could leverage the principles of LBM for simulating complex spin systems, with applications to spintronics.
Embedded Lattice and Properties of Gram Matrix
Directory of Open Access Journals (Sweden)
Futa Yuichi
2017-03-01
Full Text Available In this article, we formalize in Mizar [14] the definition of embedding of lattice and its properties. We formally define an inner product on an embedded module. We also formalize properties of Gram matrix. We formally prove that an inverse of Gram matrix for a rational lattice exists. Lattice of Z-module is necessary for lattice problems, LLL (Lenstra, Lenstra and Lov´asz base reduction algorithm [16] and cryptographic systems with lattice [17].
Loading Arbitrary Knowledge Bases in Matrix Browser
2009-01-01
This paper describes the work done on Matrix Browser, which is a recently developed graphical user interface to explore and navigate complex networked information spaces. This approach presents a new way of navigating information nets in windows explorer like widget. The problem on hand was how to export arbitrary knowledge bases in Matrix Browser. This was achieved by identifying the relationships present in knowledge bases and then by forming the hierarchies from this data and these hierarc...
Modulation of the matrix redox signaling by mitochondrial Ca(2.).
Santo-Domingo, Jaime; Wiederkehr, Andreas; De Marchi, Umberto
2015-11-26
Mitochondria sense, shape and integrate signals, and thus function as central players in cellular signal transduction. Ca(2+) waves and redox reactions are two such intracellular signals modulated by mitochondria. Mitochondrial Ca(2+) transport is of utmost physio-pathological relevance with a strong impact on metabolism and cell fate. Despite its importance, the molecular nature of the proteins involved in mitochondrial Ca(2+) transport has been revealed only recently. Mitochondrial Ca(2+) promotes energy metabolism through the activation of matrix dehydrogenases and down-stream stimulation of the respiratory chain. These changes also alter the mitochondrial NAD(P)H/NAD(P)(+) ratio, but at the same time will increase reactive oxygen species (ROS) production. Reducing equivalents and ROS are having opposite effects on the mitochondrial redox state, which are hard to dissect. With the recent development of genetically encoded mitochondrial-targeted redox-sensitive sensors, real-time monitoring of matrix thiol redox dynamics has become possible. The discoveries of the molecular nature of mitochondrial transporters of Ca(2+) combined with the utilization of the novel redox sensors is shedding light on the complex relation between mitochondrial Ca(2+) and redox signals and their impact on cell function. In this review, we describe mitochondrial Ca(2+) handling, focusing on a number of newly identified proteins involved in mitochondrial Ca(2+) uptake and release. We further discuss our recent findings, revealing how mitochondrial Ca(2+) influences the matrix redox state. As a result, mitochondrial Ca(2+) is able to modulate the many mitochondrial redox-regulated processes linked to normal physiology and disease.
Elongated polyproline motifs facilitate enamel evolution through matrix subunit compaction.
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Tianquan Jin
2009-12-01
Full Text Available Vertebrate body designs rely on hydroxyapatite as the principal mineral component of relatively light-weight, articulated endoskeletons and sophisticated tooth-bearing jaws, facilitating rapid movement and efficient predation. Biological mineralization and skeletal growth are frequently accomplished through proteins containing polyproline repeat elements. Through their well-defined yet mobile and flexible structure polyproline-rich proteins control mineral shape and contribute many other biological functions including Alzheimer's amyloid aggregation and prolamine plant storage. In the present study we have hypothesized that polyproline repeat proteins exert their control over biological events such as mineral growth, plaque aggregation, or viscous adhesion by altering the length of their central repeat domain, resulting in dramatic changes in supramolecular assembly dimensions. In order to test our hypothesis, we have used the vertebrate mineralization protein amelogenin as an exemplar and determined the biological effect of the four-fold increased polyproline tandem repeat length in the amphibian/mammalian transition. To study the effect of polyproline repeat length on matrix assembly, protein structure, and apatite crystal growth, we have measured supramolecular assembly dimensions in various vertebrates using atomic force microscopy, tested the effect of protein assemblies on crystal growth by electron microscopy, generated a transgenic mouse model to examine the effect of an abbreviated polyproline sequence on crystal growth, and determined the structure of polyproline repeat elements using 3D NMR. Our study shows that an increase in PXX/PXQ tandem repeat motif length results (i in a compaction of protein matrix subunit dimensions, (ii reduced conformational variability, (iii an increase in polyproline II helices, and (iv promotion of apatite crystal length. Together, these findings establish a direct relationship between polyproline tandem
Modulation of the matrix redox signaling by mitochondrial Ca2+
Institute of Scientific and Technical Information of China (English)
Jaime; Santo-Domingo; Andreas; Wiederkehr; Umberto; De; Marchi
2015-01-01
Mitochondria sense,shape and integrate signals,and thus function as central players in cellular signal transduction. Ca2+ waves and redox reactions are two such intracellular signals modulated by mitochondria. Mitochondrial Ca2+ transport is of utmost physio-pathological relevance with a strong impact on metabolism and cell fate. Despite its importance,the molecular nature of the proteins involvedin mitochondrial Ca2+ transport has been revealed only recently. Mitochondrial Ca2+ promotes energy metabolism through the activation of matrix dehydrogenases and downstream stimulation of the respiratory chain. These changes also alter the mitochondrial NAD(P)H/NAD(P)+ ratio,but at the same time will increase reactive oxygen species(ROS) production. Reducing equivalents and ROS are having opposite effects on the mitochondrial redox state,which are hard to dissect. With the recent development of genetically encoded mitochondrial-targeted redoxsensitive sensors,real-time monitoring of matrix thiol redox dynamics has become possible. The discoveries of the molecular nature of mitochondrial transporters of Ca2+ combined with the utilization of the novel redox sensors is shedding light on the complex relation between mitochondrial Ca2+ and redox signals and their impact on cell function. In this review,we describe mitochondrial Ca2+ handling,focusing on a number of newly identified proteins involved in mitochondrial Ca2+ uptake and release. We further discuss our recent findings,revealing how mitochondrial Ca2+ influences the matrix redox state. As a result,mitochondrial Ca2+ is able to modulate the many mitochondrial redox-regulated processes linked to normal physiology and disease.
Directory of Open Access Journals (Sweden)
Kalidindi Sita Rama Raju
2016-07-01
Full Text Available A uniform distribution of nanoparticles in the matrix plays a prominent role in improving the composite strength. In the present investigation, two types of launching vehicles, such as aluminum powder (primary and CNTs (secondary, are considered to uniformly carry and launch ultra-fine nanoparticles (13 nm into molten metal. The use of a secondary launching vehicle is identified to promote strengthening compared to a regular primary vehicle, as indicated by the good distribution observed from electron micrographs. CNTs are responsible for hybridizing the composite and also assist strengthening by anchoring to the matrix through the destroyed outer-walls and their axial orientation with the matrix. These results help us in attaining a strength of 197 MPa and a hardness of 93 BHN, with a minimal loss in ductility for the H-3 sample.
Garlanda, Cecilia; Jaillon, Sebastien; Doni, Andrea; Bottazzi, Barbara; Mantovani, Alberto
2016-02-01
Innate immunity consists of a cellular and a humoral arm. PTX3 is a fluid patter recognition molecule (PRM) with antibody-like properties. Gene targeted mice and genetic associations in humans suggest that PTX3 plays a non-redundant role in resistance against selected pathogens (e.g. Aspergillus fumigatus, Pseudomonas aeruginosa, uropathogenic Escherichia coli) and in the regulation of inflammation. PTX3 acts as an extrinsic oncosuppressor by taming complement elicited tumor-promoting inflammation. Recent results indicate that, by interacting with provisional matrix components, PTX3 contributes to the orchestration of tissue repair. An acidic pH sets PTX3 in a tissue repair mode, while retaining anti-microbial recognition. Based on these data and scattered information on humoral PRM and matrix components, we surmise that matrix and microbial recognition are related functions in evolution. Copyright © 2015 Elsevier Ltd. All rights reserved.
Expression of RECK and matrix metalloproteinase-2 in ameloblastoma
2009-01-01
Background Ameloblastoma is a frequent odontogenic benign tumor characterized by local invasiveness, high risk of recurrence and occasional metastasis and malignant transformation. Matrix metalloproteinase-2 (MMP-2) promotes tumor invasion and progression by destroying the extracellular matrix (ECM) and basement membrane. For this proteolytic activity, the endogenous inhibitor is reversion-inducing cysteine rich protein with Kazal motifs (RECK). The aim of this study was to characterize the relationship between RECK and MMP-2 expression and the clinical manifestation of ameloblastoma. Methods Immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR) were employed to detect the protein and mRNA expression of RECK and MMP-2 in keratocystic odontogenic tumor (KCOT), ameloblastoma and ameloblastic carcinoma. Results RECK protein expression was significantly reduced in KCOT (87.5%), ameloblastoma (56.5%) and ameloblastic carcinoma (0%) (P ameloblastoma compared with primary ameloblastoma (P ameloblastoma. MMP-2 protein expression was significantly higher in ameloblastoma and ameloblastic carcinoma compared with KCOT (P ameloblastoma than in KCOT (P ameloblastoma than in primary ameloblastoma, and was negative in ameloblastic carcinoma. MMP-2 mRNA expression was significantly higher in ameloblastoma compared with KCOT (P ameloblastoma versus primary ameloblastoma. RECK protein expression was negatively associated with MMP-2 protein expression in ameloblastoma (r = -0.431, P ameloblastoma. RECK may participate in the invasion, recurrence and malignant transformation of ameloblastoma by regulating MMP-2 at the post-transcriptional level. PMID:19995435
Expression of RECK and matrix metalloproteinase-2 in ameloblastoma
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Xie Hong-Liang
2009-12-01
Full Text Available Abstract Background Ameloblastoma is a frequent odontogenic benign tumor characterized by local invasiveness, high risk of recurrence and occasional metastasis and malignant transformation. Matrix metalloproteinase-2 (MMP-2 promotes tumor invasion and progression by destroying the extracellular matrix (ECM and basement membrane. For this proteolytic activity, the endogenous inhibitor is reversion-inducing cysteine rich protein with Kazal motifs (RECK. The aim of this study was to characterize the relationship between RECK and MMP-2 expression and the clinical manifestation of ameloblastoma. Methods Immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR were employed to detect the protein and mRNA expression of RECK and MMP-2 in keratocystic odontogenic tumor (KCOT, ameloblastoma and ameloblastic carcinoma. Results RECK protein expression was significantly reduced in KCOT (87.5%, ameloblastoma (56.5% and ameloblastic carcinoma (0% (P Conclusion Low or no RECK expression and increased MMP-2 expression may be associated with negative clinical findings in ameloblastoma. RECK may participate in the invasion, recurrence and malignant transformation of ameloblastoma by regulating MMP-2 at the post-transcriptional level.
The regulation of matrix metalloproteinases and their inhibitors.
Clark, Ian M; Swingler, Tracey E; Sampieri, Clara L; Edwards, Dylan R
2008-01-01
The matrix metalloproteinases (MMP) are a family of 23 enzymes in man. These enzymes were originally described as cleaving extracellular matrix (ECM) substrates with a predominant role in ECM homeostasis, but it is now clear that they have much wider functionality. Control over MMP and/or tissue inhibitor of metalloproteinases (TIMP) activity in vivo occurs at different levels and involves factors such as regulation of gene expression, activation of zymogens and inhibition of active enzymes by specific inhibitors. Whilst these enzymes and inhibitors have clear roles in physiological tissue turnover and homeostasis, if control of their expression or activity is lost, they contribute to a number of pathologies including e.g. cancer, arthritis and cardiovascular disease. The expression of many MMPs and TIMPs is regulated at the level of transcription by a variety of growth factors, cytokines and chemokines, though post-transcriptional pathways may contribute to this regulation in specific cases. The contribution of epigenetic modifications has also been uncovered in recent years. The promoter regions of many of these genes have been, at least partly, characterised including the role of identified single nucleotide polymorphisms. This article aims to review current knowledge across these gene families and use a bioinformatic approach to fill the gaps where no functional data are available.
Condensation Dynamics on Mimicked Metal Matrix Hydrophobic Nanoparticle-Composites
Damle, Viraj; Sun, Xiaoda; Rykaczewski, Konrad
2014-11-01
Use of hydrophobic surfaces promotes condensation in the dropwise mode, which is significantly more efficient than the common filmwise mode. However, limited longevity of hydrophobic surface modifiers has prevented their wide spread use in industry. Recently, metal matrix composites (MMCs) having microscale hydrophobic heterogeneities dispersed in hydrophilic metal matrix have been proposed as durable and self-healing alternative to hydrophobic surface coatings interacting with deposited water droplets. While dispersion of hydrophobic microparticles in MMC is likely to lead to surface flooding during condensation, the effect of dispersion of hydrophobic nanoparticles (HNPs) with size comparable to water nuclei critical radii and spacing is not obvious. To this end, we fabricated highly ordered arrays of Teflon nanospheres on silicon substrates that mimic the top surface of the MMCs with dispersed HNPs. We used light and electron microscopy to observe breath figures resulting from condensation on these surfaces at varied degrees of subcooling. Here, we discuss the relation between the droplet size distribution, Teflon nanosphere diameter and spacing, and condensation mode. KR acknowledges startup funding from ASU.
Metronidazole release using natural rubber latex as matrix
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Rondinelli Donizetti Herculano
2010-03-01
Full Text Available Natural Rubber Latex (NRL can be used successfully in controlled release drug delivery due to their excellent matrix forming properties. Recently, NRL has shown to stimulate angiogenesis, cellular adhesion and the formation of extracellular matrix, promoting the replacement and regeneration of tissue. A dermatological delivery system comprising a topically acceptable, inert support impregnated with a metronidazole (MET solution was developed. MET 2-(2- methyl- 5-nitro- 1H- imidazol- 1-yl ethanol, has been widely used for the treatment of protozoa and anaerobic bacterial infections. MET is a nitroimidazole anti-infective medication used mainly in the treatment of infections caused by susceptible organisms, particularly anaerobic bacteria and protozoa. In a previous study, we have tested NRL as an occlusive membrane for GBR with promising results. One possible way to decrease the inflammatory process, it was incorporated the MET in NRL. MET was incorporated into the NRL, by mixing it in solution for in vitro protein delivery experiments. The solutions of latex and MET were polymerized at different temperatures, from -100 to 40 °C, in order to control the membrane morphology. SEM microscopy analysis showed that the number, size and distribution of pores in NRL membranes varied depending on polymerization temperature, as well as its overall morphology. Results demonstrated that the best drug-delivery system was the membrane polymerized at -100 °C, which does release 77,1% of its MET content for up 310 hours.
Matrix Model for Choosing Green Marketing Sustainable Strategic Alternatives
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Cătălina Sitnikov
2015-08-01
Full Text Available Green marketing examines the symbiotic role played by marketing in ensuring sustainable business, exploring issues concerning the environment and the way strategic decisions can influence it. At present, the environmental issues concern more and more the competitive approach any organization can implement. Based on this approach, organizations can gain competitive advantage by managing environmental variables and by developing and implementing green marketing strategies. Considering the importance and impact of green marketing, by using theoretical concepts and defining a set of research directions, the paper and the research conducted were focused on creating a matrix model for choosing the optimal green marketing strategy, oriented towards competitive advantage. The model is based on the correlation that can be established among the generic strategies of competitive advantage, the variables of extended marketing mix (7Ps and the green marketing strategy matrix. There are also analyzed the implications that may be generated within a company by the adoption of a green marketing strategy and its role in promoting the environmental benefits of products.
Density matrix of black hole radiation
Alberte, Lasma; Khmelnitsky, Andrei; Medved, A J M
2015-01-01
Hawking's model of black hole evaporation is not unitary and leads to a mixed density matrix for the emitted radiation, while the Page model describes a unitary evaporation process in which the density matrix evolves from an almost thermal state to a pure state. We compare a recently proposed model of semiclassical black hole evaporation to the two established models. In particular, we study the density matrix of the outgoing radiation and determine how the magnitude of the off-diagonal corrections differs for the three frameworks. For Hawking's model, we find power-law corrections to the two-point functions that induce exponentially suppressed corrections to the off-diagonal elements of the full density matrix. This verifies that the Hawking result is correct to all orders in perturbation theory and also allows one to express the full density matrix in terms of the single-particle density matrix. We then consider the semiclassical theory for which the corrections, being non-perturbative from an effective fie...
Genetic Relationships Between Chondrules, Rims and Matrix
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.
Interfaces between a fibre and its matrix
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.