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Sample records for acid similarity matrix

  1. Derivation of an amino acid similarity matrix for peptide:MHC binding and its application as a Bayesian prior

    Directory of Open Access Journals (Sweden)

    Sette Alessandro

    2009-11-01

    Full Text Available Abstract Background Experts in peptide:MHC binding studies are often able to estimate the impact of a single residue substitution based on a heuristic understanding of amino acid similarity in an experimental context. Our aim is to quantify this measure of similarity to improve peptide:MHC binding prediction methods. This should help compensate for holes and bias in the sequence space coverage of existing peptide binding datasets. Results Here, a novel amino acid similarity matrix (PMBEC is directly derived from the binding affinity data of combinatorial peptide mixtures. Like BLOSUM62, this matrix captures well-known physicochemical properties of amino acid residues. However, PMBEC differs markedly from existing matrices in cases where residue substitution involves a reversal of electrostatic charge. To demonstrate its usefulness, we have developed a new peptide:MHC class I binding prediction method, using the matrix as a Bayesian prior. We show that the new method can compensate for missing information on specific residues in the training data. We also carried out a large-scale benchmark, and its results indicate that prediction performance of the new method is comparable to that of the best neural network based approaches for peptide:MHC class I binding. Conclusion A novel amino acid similarity matrix has been derived for peptide:MHC binding interactions. One prominent feature of the matrix is that it disfavors substitution of residues with opposite charges. Given that the matrix was derived from experimentally determined peptide:MHC binding affinity measurements, this feature is likely shared by all peptide:protein interactions. In addition, we have demonstrated the usefulness of the matrix as a Bayesian prior in an improved scoring-matrix based peptide:MHC class I prediction method. A software implementation of the method is available at: http://www.mhc-pathway.net/smmpmbec.

  2. Musical structure analysis using similarity matrix and dynamic programming

    Science.gov (United States)

    Shiu, Yu; Jeong, Hong; Kuo, C.-C. Jay

    2005-10-01

    Automatic music segmentation and structure analysis from audio waveforms based on a three-level hierarchy is examined in this research, where the three-level hierarchy includes notes, measures and parts. The pitch class profile (PCP) feature is first extracted at the note level. Then, a similarity matrix is constructed at the measure level, where a dynamic time warping (DTW) technique is used to enhance the similarity computation by taking the temporal distortion of similar audio segments into account. By processing the similarity matrix, we can obtain a coarse-grain music segmentation result. Finally, dynamic programming is applied to the coarse-grain segments so that a song can be decomposed into several major parts such as intro, verse, chorus, bridge and outro. The performance of the proposed music structure analysis system is demonstrated for pop and rock music.

  3. Wavelet matrix transform for time-series similarity measurement

    Institute of Scientific and Technical Information of China (English)

    HU Zhi-kun; XU Fei; GUI Wei-hua; YANG Chun-hua

    2009-01-01

    A time-series similarity measurement method based on wavelet and matrix transform was proposed, and its anti-noise ability, sensitivity and accuracy were discussed. The time-series sequences were compressed into wavelet subspace, and sample feature vector and orthogonal basics of sample time-series sequences were obtained by K-L transform. Then the inner product transform was carried out to project analyzed time-series sequence into orthogonal basics to gain analyzed feature vectors. The similarity was calculated between sample feature vector and analyzed feature vector by the Euclid distance. Taking fault wave of power electronic devices for example, the experimental results show that the proposed method has low dimension of feature vector, the anti-noise ability of proposed method is 30 times as large as that of plain wavelet method, the sensitivity of proposed method is 1/3 as large as that of plain wavelet method, and the accuracy of proposed method is higher than that of the wavelet singular value decomposition method. The proposed method can be applied in similarity matching and indexing for lager time series databases.

  4. Fragmentation of extracellular matrix by hypochlorous acid

    DEFF Research Database (Denmark)

    Woods, Alan A; Davies, Michael Jonathan

    2003-01-01

    of the MPO-derived oxidant hypochlorous acid (HOCl) with extracellular matrix from vascular smooth muscle cells and healthy pig arteries has been examined. HOCl is rapidly consumed by such matrix samples, with the formation of matrix-derived chloramines or chloramides. The yield of these intermediates...... increases with HOCl dose. These materials undergo a time- and temperature-dependent decay, which parallels the release of sugar and protein components from the treated matrix, consistent with these species being important intermediates. Matrix damage is enhanced by species that increase chloramine...

  5. Systematic Exploration of an Efficient Amino Acid Substitution Matrix: MIQS.

    Science.gov (United States)

    Tomii, Kentaro; Yamada, Kazunori

    2016-01-01

    Amino acid sequence comparisons to find similarities between proteins are fundamental sequence information analyses for inferring protein structure and function. In this study, we improve amino acid substitution matrices to identify distantly related proteins. We systematically sampled and benchmarked substitution matrices generated from the principal component analysis (PCA) subspace based on a set of typical existing matrices. Based on the benchmark results, we identified a region of highly sensitive matrices in the PCA subspace using kernel density estimation (KDE). Using the PCA subspace, we were able to deduce a novel sensitive matrix, called MIQS, which shows better detection performance for detecting distantly related proteins than those of existing matrices. This approach to derive an efficient amino acid substitution matrix might influence many fields of protein sequence analysis. MIQS is available at http://csas.cbrc.jp/Ssearch/ . PMID:27115635

  6. Paper Similarity Detection Method Based on Distance Matrix Model with Row-Column Order Penalty Factor

    Directory of Open Access Journals (Sweden)

    Jun Li

    2014-08-01

    Full Text Available Paper similarity detection depends on grammatical and semantic analysis, word segmentation, similarity detection, document summarization and other technologies, involving multiple disciplines. However, there are some problems in the existing main detection models, such as incomplete segmentation preprocessing specification, impact of the semantic orders on detection, near-synonym evaluation, difficulties in paper backtrack and etc. Therefore, this paper presents a two-step segmentation model of special identifier and Sharpley value specific to above problems, which can improve segmentation accuracy. In the aspect of similarity comparison, a distance matrix model with row-column order penalty factor is proposed, which recognizes new words through search engine exponent. This model integrates the characteristics of vector detection, hamming distance and the longest common substring and carries out detection specific to near-synonyms, word deletion and changes in word order by redefining distance matrix and adding ordinal measures, making sentence similarity detection in terms of semantics and backbone word segmentation more effective. Compared with the traditional paper similarity retrieval, the present method has advantages in accuracy of word segmentation, low computation, reliability and high efficiency, which is of great academic significance in word segmentation, similarity detection and document summarization.

  7. Oil-free hyaluronic acid matrix for serial femtosecond crystallography

    Science.gov (United States)

    Sugahara, Michihiro; Song, Changyong; Suzuki, Mamoru; Masuda, Tetsuya; Inoue, Shigeyuki; Nakane, Takanori; Yumoto, Fumiaki; Nango, Eriko; Tanaka, Rie; Tono, Kensuke; Joti, Yasumasa; Kameshima, Takashi; Hatsui, Takaki; Yabashi, Makina; Nureki, Osamu; Numata, Keiji; Iwata, So

    2016-04-01

    The grease matrix was originally introduced as a microcrystal-carrier for serial femtosecond crystallography and has been expanded to applications for various types of proteins, including membrane proteins. However, the grease-based matrix has limited application for oil-sensitive proteins. Here we introduce a grease-free, water-based hyaluronic acid matrix. Applications for proteinase K and lysozyme proteins were able to produce electron density maps at 2.3-Å resolution.

  8. Matrix member for containing fuel cell acid electrolyte

    International Nuclear Information System (INIS)

    A matrix member for carrying the acid electrolyte of a fuel cell comprised of a first layer containing a carbon material and a second layer containing a silicon carbide material. A further matrix member is disclosed wherein the mean pore size of the member is substantially equal to or less than that mean pore size of at least one of the fuel cell electrodes

  9. Analysis of amino acids network based on distance matrix

    Science.gov (United States)

    Ali, Tazid; Akhtar, Adil; Gohain, Nisha

    2016-06-01

    In this paper we have constructed a distance matrix of the amino acids. The distance is defined based on the relative evolutionary importance of the base position of the corresponding codons. From this distance matrix a network of the amino acids is obtained. We have argued that this network depicts the evolutionary pattern of the amino acids. To examine the relative importance of the amino acids with respect to this network we have discussed different measures of centrality. We have also investigated the correlation coefficients between different measures of centrality. Further we have explored clustering coefficient as well as degree of distribution.

  10. Community structure discovery method based on the Gaussian kernel similarity matrix

    Science.gov (United States)

    Guo, Chonghui; Zhao, Haipeng

    2012-03-01

    Community structure discovery in complex networks is a popular issue, and overlapping community structure discovery in academic research has become one of the hot spots. Based on the Gaussian kernel similarity matrix and spectral bisection, this paper proposes a new community structure discovery method. First, by adjusting the Gaussian kernel parameter to change the scale of similarity, we can find the corresponding non-overlapping community structure when the value of the modularity is the largest relatively. Second, the changes of the Gaussian kernel parameter would lead to the unstable nodes jumping off, so with a slight change in method of non-overlapping community discovery, we can find the overlapping community nodes. Finally, synthetic data, karate club and political books datasets are used to test the proposed method, comparing with some other community discovery methods, to demonstrate the feasibility and effectiveness of this method.

  11. One Shot Detection with Laplacian Object and Fast Matrix Cosine Similarity.

    Science.gov (United States)

    Biswas, Sujoy Kumar; Milanfar, Peyman

    2016-03-01

    One shot, generic object detection involves searching for a single query object in a larger target image. Relevant approaches have benefited from features that typically model the local similarity patterns. In this paper, we combine local similarity (encoded by local descriptors) with a global context (i.e., a graph structure) of pairwise affinities among the local descriptors, embedding the query descriptors into a low dimensional but discriminatory subspace. Unlike principal components that preserve global structure of feature space, we actually seek a linear approximation to the Laplacian eigenmap that permits us a locality preserving embedding of high dimensional region descriptors. Our second contribution is an accelerated but exact computation of matrix cosine similarity as the decision rule for detection, obviating the computationally expensive sliding window search. We leverage the power of Fourier transform combined with integral image to achieve superior runtime efficiency that allows us to test multiple hypotheses (for pose estimation) within a reasonably short time. Our approach to one shot detection is training-free, and experiments on the standard data sets confirm the efficacy of our model. Besides, low computation cost of the proposed (codebook-free) object detector facilitates rather straightforward query detection in large data sets including movie videos. PMID:27046497

  12. Similarity matrix analysis and divergence measures for statistical detection of unknown deterministic signals hidden in additive noise

    International Nuclear Information System (INIS)

    This Letter proposes an algorithm to detect an unknown deterministic signal hidden in additive white Gaussian noise. The detector is based on recurrence analysis. It compares the distribution of the similarity matrix coefficients of the measured signal with an analytic expression of the distribution expected in the noise-only case. This comparison is achieved using divergence measures. Performance analysis based on the receiver operating characteristics shows that the proposed detector outperforms the energy detector, giving a probability of detection 10% to 50% higher, and has a similar performance to that of a sub-optimal filter detector. - Highlights: • We model the distribution of the similarity matrix coefficients of a Gaussian noise. • We use divergence measures for goodness-of-fit test between a model and measured data. • We distinguish deterministic signal and Gaussian noise with similarity matrix analysis. • Similarity matrix analysis outperforms energy detector

  13. Similarity matrix analysis and divergence measures for statistical detection of unknown deterministic signals hidden in additive noise

    Energy Technology Data Exchange (ETDEWEB)

    Le Bot, O., E-mail: lebotol@gmail.com [Univ. Grenoble Alpes, GIPSA-Lab, F-38000 Grenoble (France); CNRS, GIPSA-Lab, F-38000 Grenoble (France); Mars, J.I. [Univ. Grenoble Alpes, GIPSA-Lab, F-38000 Grenoble (France); CNRS, GIPSA-Lab, F-38000 Grenoble (France); Gervaise, C. [Univ. Grenoble Alpes, GIPSA-Lab, F-38000 Grenoble (France); CNRS, GIPSA-Lab, F-38000 Grenoble (France); Chaire CHORUS, Foundation of Grenoble Institute of Technology, 46 Avenue Félix Viallet, 38031 Grenoble Cedex 1 (France)

    2015-10-23

    This Letter proposes an algorithm to detect an unknown deterministic signal hidden in additive white Gaussian noise. The detector is based on recurrence analysis. It compares the distribution of the similarity matrix coefficients of the measured signal with an analytic expression of the distribution expected in the noise-only case. This comparison is achieved using divergence measures. Performance analysis based on the receiver operating characteristics shows that the proposed detector outperforms the energy detector, giving a probability of detection 10% to 50% higher, and has a similar performance to that of a sub-optimal filter detector. - Highlights: • We model the distribution of the similarity matrix coefficients of a Gaussian noise. • We use divergence measures for goodness-of-fit test between a model and measured data. • We distinguish deterministic signal and Gaussian noise with similarity matrix analysis. • Similarity matrix analysis outperforms energy detector.

  14. Anacardic Acid Inhibits the Catalytic Activity of Matrix Metalloproteinase-2 and Matrix Metalloproteinase-9

    OpenAIRE

    Omanakuttan, Athira; Nambiar, Jyotsna; Harris, Rodney M.; Bose, Chinchu; Pandurangan, Nanjan; Varghese, Rebu K.; Kumar, Geetha B.; Tainer, John A; Banerji, Asoke; Perry, J. Jefferson P.; Nair, Bipin G

    2012-01-01

    Cashew nut shell liquid (CNSL) has been used in traditional medicine for the treatment of a wide variety of pathophysiological conditions. To further define the mechanism of CNSL action, we investigated the effect of cashew nut shell extract (CNSE) on two matrix metalloproteinases, MMP-2/gelatinase A and MMP-9/gelatinase B, which are known to have critical roles in several disease states. We observed that the major constituent of CNSE, anacardic acid, markedly inhibited the gelatinase activit...

  15. GLYCOLIC-FORMIC ACID FLOWSHEET SLUDGE MATRIX STUDY

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, D.; Koopman, D.

    2011-06-30

    Testing was completed to demonstrate the viability of the newly developed glycolic acid/formic acid flowsheet on processing in the Defense Waste Processing Facility's (DWPF) Chemical Process Cell (CPC). The Savannah River National Laboratory (SRNL) initiated a sludge matrix study to evaluate the impact of changing insoluble solid composition on the processing characteristics of slurries in DWPF. Four sludge simulants were prepared to cover two compositional ranges in the waste. The first was high iron/low aluminum versus low iron/high aluminum (referred to as HiFe or LoFe in this report). The second was high calcium-manganese/low nickel, chromium, and magnesium versus low calcium-manganese/high nickel, chromium, and magnesium (referred to as HiMn or LoMn in this report). These two options can be combined to form four distinct sludge compositions. The sludge matrix study called for testing each of these four simulants near the minimum acid required for nitrite destruction (100% acid stoichiometry) and at a second acid level that produced significant hydrogen by noble metal catalyzed decomposition of formic acid (150% acid stoichiometry). Four simulants were prepared based on the four possible combinations of the Al/Fe and Mn-Ca/Mg-Ni-Cr options. Preliminary simulant preparation work has already been documented. The four simulants were used for high and low acid testing. Eight planned experiments (GF26 to GF33) were completed to demonstrate the viability of the glycolic-formic flowsheet. Composition and physical property measurements were made on the SRAT product. Composition measurements were made on the condensate from the Mercury Water Wash Tank (MWWT), Formic Acid Vent Condenser (FAVC), ammonia scrubber and on SRAT samples pulled throughout the SRAT cycle. Updated values for formate loss and nitrite-tonitrate conversion were found that can be used in the acid calculations for future sludge matrix process simulations with the glycolic acid/formic acid

  16. Across bacterial phyla, distantly-related genomes with similar genomic GC content have similar patterns of amino acid usage.

    Directory of Open Access Journals (Sweden)

    John Lightfield

    Full Text Available The GC content of bacterial genomes ranges from 16% to 75% and wide ranges of genomic GC content are observed within many bacterial phyla, including both gram negative and gram positive phyla. Thus, divergent genomic GC content has evolved repeatedly in widely separated bacterial taxa. Since genomic GC content influences codon usage, we examined codon usage patterns and predicted protein amino acid content as a function of genomic GC content within eight different phyla or classes of bacteria. We found that similar patterns of codon usage and protein amino acid content have evolved independently in all eight groups of bacteria. For example, in each group, use of amino acids encoded by GC-rich codons increased by approximately 1% for each 10% increase in genomic GC content, while the use of amino acids encoded by AT-rich codons decreased by a similar amount. This consistency within every phylum and class studied led us to conclude that GC content appears to be the primary determinant of the codon and amino acid usage patterns observed in bacterial genomes. These results also indicate that selection for translational efficiency of highly expressed genes is constrained by the genomic parameters associated with the GC content of the host genome.

  17. Anacardic acid inhibits the catalytic activity of matrix metalloproteinase-2 and matrix metalloproteinase-9.

    Science.gov (United States)

    Omanakuttan, Athira; Nambiar, Jyotsna; Harris, Rodney M; Bose, Chinchu; Pandurangan, Nanjan; Varghese, Rebu K; Kumar, Geetha B; Tainer, John A; Banerji, Asoke; Perry, J Jefferson P; Nair, Bipin G

    2012-10-01

    Cashew nut shell liquid (CNSL) has been used in traditional medicine for the treatment of a wide variety of pathophysiological conditions. To further define the mechanism of CNSL action, we investigated the effect of cashew nut shell extract (CNSE) on two matrix metalloproteinases, MMP-2/gelatinase A and MMP-9/gelatinase B, which are known to have critical roles in several disease states. We observed that the major constituent of CNSE, anacardic acid, markedly inhibited the gelatinase activity of 3T3-L1 cells. Our gelatin zymography studies on these two secreted gelatinases, present in the conditioned media from 3T3-L1 cells, established that anacardic acid directly inhibited the catalytic activities of both MMP-2 and MMP-9. Our docking studies suggested that anacardic acid binds into the MMP-2/9 active site, with the carboxylate group of anacardic acid chelating the catalytic zinc ion and forming a hydrogen bond to a key catalytic glutamate side chain and the C15 aliphatic group being accommodated within the relatively large S1' pocket of these gelatinases. In agreement with the docking results, our fluorescence-based studies on the recombinant MMP-2 catalytic core domain demonstrated that anacardic acid directly inhibits substrate peptide cleavage in a dose-dependent manner, with an IC₅₀ of 11.11 μM. In addition, our gelatinase zymography and fluorescence data confirmed that the cardol-cardanol mixture, salicylic acid, and aspirin, all of which lack key functional groups present in anacardic acid, are much weaker MMP-2/MMP-9 inhibitors. Our results provide the first evidence for inhibition of gelatinase catalytic activity by anacardic acid, providing a novel template for drug discovery and a molecular mechanism potentially involved in CNSL therapeutic action. PMID:22745359

  18. Similarity matrix analysis and divergence measures for statistical detection of unknown deterministic signals hidden in additive noise

    Science.gov (United States)

    Le Bot, O.; Mars, J. I.; Gervaise, C.

    2015-10-01

    This Letter proposes an algorithm to detect an unknown deterministic signal hidden in additive white Gaussian noise. The detector is based on recurrence analysis. It compares the distribution of the similarity matrix coefficients of the measured signal with an analytic expression of the distribution expected in the noise-only case. This comparison is achieved using divergence measures. Performance analysis based on the receiver operating characteristics shows that the proposed detector outperforms the energy detector, giving a probability of detection 10% to 50% higher, and has a similar performance to that of a sub-optimal filter detector.

  19. Matrix models with Penner interaction inspired by interacting ribonucleic acid

    Indian Academy of Sciences (India)

    Pradeep Bhadola; N Deo

    2015-02-01

    The Penner interaction known in studies of moduli space of punctured Riemann surfaces is introduced and studied in the context of random matrix model of homo RNA. An analytic derivation of the generating function is given and the corresponding partition function is derived numerically. An additional dependence of the structure combinatorics factor on (related to the size of the matrix and the interaction strength) is obtained. This factor has a strong effect on the structure combinatorics in the low regime. Databases are scanned for real ribonucleic acid (RNA) structures and pairing information for these RNA structures is computationally extracted. Then the genus is calculated for every structure and plotted as a function of length. The genus distribution function is compared with the prediction from the nonlinear (NL) model. The specific heat and distribution of structure with temperature calculated from the NL model shows that the NL inter-action is biased towards planar structures. The second derivative of specific heat changes phase from a double peaked function for small to a single peak for large . Detailed analysis reveals the presence of the double peak only for genus 0 structures, the higher genii behave normally with . Comparable behaviour is found in studies involving interactions of RNA with osmolytes and monovalent cations in unfolding experiments.

  20. MALDI mechanism of dihydroxybenzoic acid isomers: desorption of neutral matrix and analyte.

    Science.gov (United States)

    Liang, Chi Wei; Lee, Chih Hao; Lin, Yu-Jiun; Lee, Yuan Tseh; Ni, Chi Kung

    2013-05-01

    Angular resolved velocity distributions of laser desorbed neutral matrices (dihydroxybenzoic acids, DHB) and analytes (tryptophan) embedded in these matrices were investigated at 322 nm by a modified crossed molecular beam apparatus. Desorbed ions generated from MALDI were measured by a time-of-flight mass spectrometer. Desorptions of neutral matrix and analyte from 2,3-DHB, 2,4-DHB, 2,5-DHB, 2,6-DHB, and 3,5--DHB at 322 nm have similar properties, but the ion intensities are in the order 2,3DHB ≅ 2,6-DHB > 2,5-DHB ≅ 2,4-DHB > 3,5-DHB. It indicates that the combination of various parameters related to neutral species, including absorption coefficient, sublimation energy, contact of analyte and matrix in crystal, and plume dynamics of desorbed species are not crucial in the determination of MALDI process for DHB isomers. The difference of matrix activity of DHB isomers at this wavelength must result from the other properties, like the excited state lifetime, proton affinity, gas-phase basicity, acidity, ionization energy, or the other properties related to the primary reactions in ion generation.

  1. The Influence of Matrix Size on Statistical Properties of Co-Occurrence and Limiting Similarity Null Models.

    Science.gov (United States)

    Lavender, Thomas Michael; Schamp, Brandon S; Lamb, Eric G

    2016-01-01

    Null models exploring species co-occurrence and trait-based limiting similarity are increasingly used to explore the influence of competition on community assembly; however, assessments of common models have not thoroughly explored the influence of variation in matrix size on error rates, in spite of the fact that studies have explored community matrices that vary considerably in size. To determine how smaller matrices, which are of greatest concern, perform statistically, we generated biologically realistic presence-absence matrices ranging in size from 3-50 species and sites, as well as associated trait matrices. We examined co-occurrence tests using the C-Score statistic and independent swap algorithm. For trait-based limiting similarity null models, we used the mean nearest neighbour trait distance (NN) and the standard deviation of nearest neighbour distances (SDNN) as test statistics, and considered two common randomization algorithms: abundance independent trait shuffling (AITS), and abundance weighted trait shuffling (AWTS). Matrices as small as three × three resulted in acceptable type I error rates (p ) was associated with increased type I error rates, particularly for matrices with fewer than eight species. Type I error rates increased for limiting similarity tests using the AWTS randomization scheme when community matrices contained more than 35 sites; a similar randomization used in null models of phylogenetic dispersion has previously been viewed as robust. Notwithstanding other potential deficiencies related to the use of small matrices to represent communities, the application of both classes of null model should be restricted to matrices with 10 or more species to avoid the possibility of type II errors. Additionally, researchers should restrict the use of the AWTS randomization to matrices with fewer than 35 sites to avoid type I errors when testing for trait-based limiting similarity. The AITS randomization scheme performed better in terms of

  2. Amino Acids Analysis by MALDI Mass Spectrometry Using Carbon Nanotube as Matrix

    Institute of Scientific and Technical Information of China (English)

    张菁; 王昊阳; 郭寅龙

    2005-01-01

    Twenty common amino acids have been analyzed successfully by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) using carbon nanotubes as matrix. From the spectra, little or no background interference or fragmentation of the analytes has been observed. This method was also applied to the analysis of amino acid mixture successfully. Carbon nanotubes have some features such as large surface area to disperse the analyte molecules sufficiently and prevent the sample aggregation and strong ultraviolet absorption to transfer energy easily to the analyte molecules. The present method has potential application for the rapid and sensitive analysis of amino acids and their mixture.

  3. Bovine lactoferrin binds oleic acid to form an anti-tumor complex similar to HAMLET.

    Science.gov (United States)

    Fang, Bing; Zhang, Ming; Tian, Mai; Jiang, Lu; Guo, Hui Yuan; Ren, Fa Zheng

    2014-04-01

    α-Lactalbumin (α-LA) can bind oleic acid (OA) to form HAMLET-like complexes, which exhibited highly selective anti-tumor activity in vitro and in vivo. Considering the structural similarity to α-LA, we conjectured that lactoferrin (LF) could also bind OA to obtain a complex with anti-tumor activity. In this study, LF-OA was prepared and its activity and structural changes were compared with α-LA-OA. The anti-tumor activity was evaluated by methylene blue assay, while the apoptosis mechanism was analyzed using flow cytometry and Western blot. Structural changes of LF-OA were measured by fluorescence spectroscopy and circular dichroism. The interactions of OA with LF and α-LA were evaluated by isothermal titration calorimetry (ITC). LF-OA was obtained by heat-treatment at pH8.0 with LD50 of 4.88, 4.95 and 4.62μM for HepG2, HT29, and MCF-7 cells, respectively, all of which were 10 times higher than those of α-LA-OA. Similar to HAMLET, LF-OA induced apoptosis in tumor cells through both death receptor- and mitochondrial-mediated pathways. Exposure of tryptophan residues and the hydrophobic regions as well as the loss of tertiary structure were observed in LF-OA. Besides these similarities, LF showed different secondary structure changes when compared with α-LA, with a decrease of α-helix and β-turn and an increase of β-sheet and random coil. ITC results showed that there was a higher binding number of OA to LF than to α-LA, while both of the proteins interacted with OA through van der Waals forces and hydrogen bonds. This study provides a theoretical basis for further exploration of protein-OA complexes. PMID:24368211

  4. Bovine lactoferrin binds oleic acid to form an anti-tumor complex similar to HAMLET.

    Science.gov (United States)

    Fang, Bing; Zhang, Ming; Tian, Mai; Jiang, Lu; Guo, Hui Yuan; Ren, Fa Zheng

    2014-04-01

    α-Lactalbumin (α-LA) can bind oleic acid (OA) to form HAMLET-like complexes, which exhibited highly selective anti-tumor activity in vitro and in vivo. Considering the structural similarity to α-LA, we conjectured that lactoferrin (LF) could also bind OA to obtain a complex with anti-tumor activity. In this study, LF-OA was prepared and its activity and structural changes were compared with α-LA-OA. The anti-tumor activity was evaluated by methylene blue assay, while the apoptosis mechanism was analyzed using flow cytometry and Western blot. Structural changes of LF-OA were measured by fluorescence spectroscopy and circular dichroism. The interactions of OA with LF and α-LA were evaluated by isothermal titration calorimetry (ITC). LF-OA was obtained by heat-treatment at pH8.0 with LD50 of 4.88, 4.95 and 4.62μM for HepG2, HT29, and MCF-7 cells, respectively, all of which were 10 times higher than those of α-LA-OA. Similar to HAMLET, LF-OA induced apoptosis in tumor cells through both death receptor- and mitochondrial-mediated pathways. Exposure of tryptophan residues and the hydrophobic regions as well as the loss of tertiary structure were observed in LF-OA. Besides these similarities, LF showed different secondary structure changes when compared with α-LA, with a decrease of α-helix and β-turn and an increase of β-sheet and random coil. ITC results showed that there was a higher binding number of OA to LF than to α-LA, while both of the proteins interacted with OA through van der Waals forces and hydrogen bonds. This study provides a theoretical basis for further exploration of protein-OA complexes.

  5. 3-Aminoquinoline/p-coumaric acid as a MALDI matrix for glycopeptides, carbohydrates, and phosphopeptides.

    Science.gov (United States)

    Fukuyama, Yuko; Funakoshi, Natsumi; Takeyama, Kohei; Hioki, Yusaku; Nishikaze, Takashi; Kaneshiro, Kaoru; Kawabata, Shin-Ichirou; Iwamoto, Shinichi; Tanaka, Koichi

    2014-02-18

    Glycosylation and phosphorylation are important post-translational modifications in biological processes and biomarker research. The difficulty in analyzing these modifications is mainly their low abundance and dissociation of labile regions such as sialic acids or phosphate groups. One solution in matrix-assisted laser desorption/ionization (MALDI) mass spectrometry is to improve matrices for glycopeptides, carbohydrates, and phosphopeptides by increasing the sensitivity and suppressing dissociation of the labile regions. Recently, a liquid matrix 3-aminoquinoline (3-AQ)/α-cyano-4-hydroxycinnamic acid (CHCA) (3-AQ/CHCA), introduced by Kolli et al. in 1996, has been reported to increase sensitivity for carbohydrates or phosphopeptides, but it has not been systematically evaluated for glycopeptides. In addition, 3-AQ/CHCA enhances the dissociation of labile regions. In contrast, a liquid matrix 1,1,3,3-tetramethylguanidium (TMG, G) salt of p-coumaric acid (CA) (G3CA) was reported to suppress dissociation of sulfate groups or sialic acids of carbohydrates. Here we introduce a liquid matrix 3-AQ/CA for glycopeptides, carbohydrates, and phosphopeptides. All of the analytes were detected as [M + H](+) or [M - H](-) with higher or comparable sensitivity using 3-AQ/CA compared with 3-AQ/CHCA or 2,5-dihydroxybenzoic acid (2,5-DHB). The sensitivity was increased 1- to 1000-fold using 3-AQ/CA. The dissociation of labile regions such as sialic acids or phosphate groups and the fragmentation of neutral carbohydrates were suppressed more using 3-AQ/CA than using 3-AQ/CHCA or 2,5-DHB. 3-AQ/CA was thus determined to be an effective MALDI matrix for high sensitivity and the suppression of dissociation of labile regions in glycosylation and phosphorylation analyses.

  6. Study of acid solution bonding in epoxy matrix for sealed radioactive sources production

    International Nuclear Information System (INIS)

    The present work aims to analyze different resin formulations. These formulations are used in the production of radioactive sealed sources that are used in many fields such as nuclear medicine; environmental analyzes, radiation detectors accuracy check, and so on. These sources can be produced with different radioisotopes and different activities, it all depending on the use they will have. Certain types of resins have the same density water. This property is appreciated when we consider that radiotracers used in nuclear medicine are applied in aqueous solutions. So the sources used for checking and calibrating equipment must have their radioisotopes sealed in a material having similar properties, thus the measures are reproducible and repetitive. The most important aspect that is brought to attention in this work is the miscibility those resins have with water. The radioisotopes for the production of the sources are supplied in an aqueous form. In case the resin and the radioisotope solution do not mix, the source will not be sturdy enough to seal the radioisotopes in its structure and the source will not be safe. There were prepared different formulations with different amounts of acid solution, and the cured formulations were analyzed by Wipe Test, DSC (Differential Splanatory Calorimetry) and also, the possible volatile aspect of the radionuclide used. All to evaluate the integrity of the sources. The obtained results were satisfactory and show that when the resin is well cured, the radioisotope remains sealed in the matrix, making it possible to produce radioactive sealed sources. (author)

  7. Fluorescence Excitation-Emission Matrix Characterization of a Commercial Humic Acid

    Institute of Scientific and Technical Information of China (English)

    傅平青; 吴丰昌; 刘丛强

    2004-01-01

    Excitation-emission matrix fluorescence spectroscopy (EEM) has been widely used to elucidate the origin and structure of humic substances in natural environments. Due to its high sensitivity, good selectivity and non-destructive advantage, the EEM was applied to characterizing a commercial Fluka humic acid (FHA). The results showed that the EEMs of FHA has several Ex/Em peaks. Ionic strength (0-0.05 mol/L KClO-4) exerted little effect on the fluorescence properties of FHA, while the concentrations (5-100 mg/L) of FHA and pH (2-12) had significant effects. A red shift in the longer wavelength peak region was observed when the concentrations or pH values increased. The fluorescence intensity increased with increasing pH, but slightly decreased in the case of pH=5.0. The protonation constants (lgK'-HL) of peak B were calculated to be 3.57 and 3.13, indicating that peak B was due to carboxyl groups. The r-(A/B) values range from 0.61 to 2.59. A strong linear relationship between r-(A/B) and pH was also observed. This indicates that the fluorescence peaks A and B posses similar inherent fluorescence characteristics.

  8. Study of acid solution bonding in epoxy matrix for sealed radioactive sources production

    Energy Technology Data Exchange (ETDEWEB)

    Benega, Marcos A.G.; Nagatomi, Helio R.; Rostelato, Maria Elisa C.M.; Tiezzi, Rodrigo; Rodrigues, Bruna T.; Peleias Junior, Fernando; Souza, Carla D.; Souza, Daiane C.C. de; Souza, Anderson S. de; Silva, Thais H. da, E-mail: carladdsouza@yahoo.com.br, E-mail: marcosagbenega@gmail.com, E-mail: hrnagato@ipen.br, E-mail: elisaros@ipen.br, E-mail: rktiezzi@gmail.com, E-mail: bteigarodrigues@gmail.com, E-mail: fernandopeleias@gmail.com, E-mail: dcsouza@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2014-07-01

    The present work aims to analyze different resin formulations. These formulations are used in the production of radioactive sealed sources that are used in many fields such as nuclear medicine; environmental analyzes, radiation detectors accuracy check, and so on. These sources can be produced with different radioisotopes and different activities, it all depending on the use they will have. Certain types of resins have the same density water. This property is appreciated when we consider that radiotracers used in nuclear medicine are applied in aqueous solutions. So the sources used for checking and calibrating equipment must have their radioisotopes sealed in a material having similar properties, thus the measures are reproducible and repetitive. The most important aspect that is brought to attention in this work is the miscibility those resins have with water. The radioisotopes for the production of the sources are supplied in an aqueous form. In case the resin and the radioisotope solution do not mix, the source will not be sturdy enough to seal the radioisotopes in its structure and the source will not be safe. There were prepared different formulations with different amounts of acid solution, and the cured formulations were analyzed by Wipe Test, DSC (Differential Splanatory Calorimetry) and also, the possible volatile aspect of the radionuclide used. All to evaluate the integrity of the sources. The obtained results were satisfactory and show that when the resin is well cured, the radioisotope remains sealed in the matrix, making it possible to produce radioactive sealed sources. (author)

  9. Matrix solid-phase dispersion for the liquid chromatographic determination of phenolic acids in Melissa officinalis.

    Science.gov (United States)

    Ziaková, Alica; Brandsteterová, Eva; Blahová, Eva

    2003-01-01

    Matrix solid-phase dispersion (MSPD) was used for sample preparation of plant material (Melissa officinalis, Lemon Balm) prior to liquid chromatography of rosmarinic, caffeic and protocatechuic acids, phenolic compounds present in this herb. Different MSPD sorbents and various elution agents were tested and the optimal extraction conditions determined with the aim to obtain extraction recoveries greater than 90% for all analytes. PMID:12568390

  10. Matrix isolation infrared spectra of O-H· · · π Hydrogen bonded complexes of Acetic acid and Trifluoroacetic acid with Benzene

    Indian Academy of Sciences (India)

    PUJARINI BANERJEE; INDRANI BHATTACHARYA; TAPAS CHAKRABORTY

    2016-10-01

    Mid infrared spectra of two O–H· · · π hydrogen-bonded binary complexes of acetic acid (AA) and trifluoroacetic acid (F₃AA) with benzene (Bz) have been measured by isolating the complexes in an argon matrix at ∼8 K. In a matrix isolation condition, the O–H stretching fundamentals (νO−H) of the carboxylic acid groups of the two molecules are observed to have almost the same value. However, the spectral red-shifts of νO−H bands of the two acids on complexation with Bz are largely different, 90 and 150 cm⁻¹ for AA and F₃AA, respectively. Thus, the O–H bond weakening of the two acids upon binding with Bz in a non-interacting environment follows the sequence of their ionic dissociation tendencies (pKa) in aqueous media. Furthermore, ΔνO−H of the latter complex is the largest among the known π-hydrogen bonded binary complexes of prototypical O–H donors reported so far with respect to Bz as acceptor. It is also observed that the spectral shifts (ΔνO−H) of phenol-Bz and carboxylic acid-Bz complexes show similar dependence on the acidity factor (pKa). Electronic structure theory has been used to suggest suitable geometries of the complexes that are consistent with the measured IR spectral changes. Calculation at MP2/6-311++G (d, p) level predicts a T-shaped geometry for both AA-Bz and F₃AA-Bz complexes, and the corresponding binding energies are 3.0 and 4.5 kcal/mol, respectively. Natural Bond Orbital (NBO) analysis has been performed to correlate the observed spectral behavior of the complexes with the electronic structure parameters.

  11. Phosphoric acid as a matrix additive for MALDI MS analysis of phosphopeptides and phosphoproteins

    DEFF Research Database (Denmark)

    Kjellström, Sven; Jensen, Ole Nørregaard

    2004-01-01

    Phosphopeptides are often detected with low efficiency by MALDI MS analysis of peptide mixtures. In an effort to improve the phosphopeptide ion response in MALDI MS, we investigated the effects of adding low concentrations of organic and inorganic acids during peptide sample preparation in 2...... acid to 2,5-DHB were also observed in LC-MALDI-MS analysis of tryptic phosphopeptides of B. subtilis PrkC phosphoprotein. Finally, the mass resolution of MALDI mass spectra of intact proteins was significantly improved by using phosphoric acid in 2,5-DHB matrix....

  12. Weighted augmented Jacobian matrix with a variable coefficient method for kinematics mapping of space teleoperation based on human-robot motion similarity

    Science.gov (United States)

    Shi, Zhong; Huang, Xuexiang; Hu, Tianjian; Tan, Qian; Hou, Yuzhuo

    2016-10-01

    Space teleoperation is an important space technology, and human-robot motion similarity can improve the flexibility and intuition of space teleoperation. This paper aims to obtain an appropriate kinematics mapping method of coupled Cartesian-joint space for space teleoperation. First, the coupled Cartesian-joint similarity principles concerning kinematics differences are defined. Then, a novel weighted augmented Jacobian matrix with a variable coefficient (WAJM-VC) method for kinematics mapping is proposed. The Jacobian matrix is augmented to achieve a global similarity of human-robot motion. A clamping weighted least norm scheme is introduced to achieve local optimizations, and the operating ratio coefficient is variable to pursue similarity in the elbow joint. Similarity in Cartesian space and the property of joint constraint satisfaction is analysed to determine the damping factor and clamping velocity. Finally, a teleoperation system based on human motion capture is established, and the experimental results indicate that the proposed WAJM-VC method can improve the flexibility and intuition of space teleoperation to complete complex space tasks.

  13. Correction of tear trough deformity with a cohesive polydensified matrix hyaluronic acid: a case series

    OpenAIRE

    Huber-Vorländer J; Kürten M

    2015-01-01

    Jürgen Huber-Vorländer, Martin KürtenFort Malakoff Klinik, Mainz, GermanyAbstract: The tear trough or infraorbital hollow is a challenging area to treat, and only a few fillers are suitable for this delicate area. We report on a European case series of six subjects with mild to severe tear troughs who received treatment with cohesive polydensified matrix (CPM®) technology hyaluronic acid gel (Belotero® Balance). The product was injected as small depo...

  14. Poly(lactic-co-glycolic acid) matrix incorporated with nisin as a novel antimicrobial biomaterial.

    Science.gov (United States)

    Correia, Rafaela Coelho; Jozala, Angela Faustino; Martins, Kelly Fernanda; Penna, Thereza Christina Vessoni; Duek, Eliana Aparecida de Rezende; Rangel-Yagui, Carlota de Oliveira; Lopes, André Moreni

    2015-04-01

    The use of poly(lactic-co-glycolic acid) (PLGA) matrix as a biomolecule carrier has been receiving great attention due to its potential therapeutic application. In this context, we investigated the PLGA matrix capacity to incorporate nisin, an antimicrobial peptide capable of inhibiting the growth of Gram-positive bacteria and bacterial spores germination. Nisin-incorporated PLGA matrices were evaluated based on the inhibitory effect against the nisin-bioindicator Lactobacillus sakei. Additionally, the PLGA-nisin matrix stability over an 8-months period was investigated, as well as the nisin release profile. For the incorporation conditions, we observed that a 5 h incorporation time, at 30 °C, with 250 μg/mL nisin solution in PBS buffer pH 4.5, resulted in the highest inhibitory activity of 2.70 logAU/mL. The PLGA-nisin matrix was found to be relatively stable and showed sustained drug delivery, with continuous release of nisin for 2 weeks. Therefore, PLGA-nisin matrix is could be used as a novel antimicrobial delivery system and an alternative to antibiotics incorporated into PLGA matrices.

  15. Gossypol-cross-linked boronic acid-modified hydrogels: a functional matrix for the controlled release of an anticancer drug.

    Science.gov (United States)

    Heleg-Shabtai, Vered; Aizen, Ruth; Orbach, Ron; Aleman-Garcia, Miguel Angel; Willner, Itamar

    2015-02-24

    Anticancer drug gossypol cross-links phenylboronic acid-modified acrylamide copolymer chains to form a hydrogel matrix. The hydrogel is dissociated in an acidic environment (pH 4.5), and its dissociation is enhanced in the presence of lactic acid (an α-hydroxy carboxylic acid) as compared to formic acid. The enhanced dissociation of the hydrogel by lactic acid is attributed to the effective separation of the boronate ester bridging groups through the formation of a stabilized complex between the boronic acid substituent and the lactic acid. Because lactic acid exists in cancer cells in elevated amounts and the cancer cells' environment is acidic, the cross-linked hydrogel represents a stimuli-responsive matrix for the controlled release of gossypol. The functionality is demonstrated and characterized by rheology and other spectroscopic means. PMID:25664656

  16. Correction of tear trough deformity with a cohesive polydensified matrix hyaluronic acid: a case series

    Directory of Open Access Journals (Sweden)

    Huber-Vorländer J

    2015-06-01

    Full Text Available Jürgen Huber-Vorländer, Martin KürtenFort Malakoff Klinik, Mainz, GermanyAbstract: The tear trough or infraorbital hollow is a challenging area to treat, and only a few fillers are suitable for this delicate area. We report on a European case series of six subjects with mild to severe tear troughs who received treatment with cohesive polydensified matrix (CPM® technology hyaluronic acid gel (Belotero® Balance. The product was injected as small depots (up to ten small boli 0.2 mL maximum each per side at the supraperiosteal level along or below the orbital rim. Follow-up visits took place at 1, 3, 6, and 9 months after injection for independent evaluation of the clinical effect using the Merz Aesthetics Scale™ for infraorbital hollows and the Global Aesthetic Improvement Scale. Adverse events were also recorded. Mean hollowness scores were considerably improved compared with baseline in all subjects. In all women, the improvements remained throughout the 9-month study, with none reverting to their baseline score. Subjects’ satisfaction with treatment was very high throughout the study, and all women stated that they would repeat treatment with the same product. The CPM hyaluronic acid gel was well tolerated. CPM hyaluronic acid gel is a safe and effective treatment for the tear trough area.Keywords: Belotero® Balance, cohesive polydensified matrix (CPM®, hyaluronic acid, infraorbital hollow, tear trough

  17. TG containing stearic acid, synthesized from coconut oil, exhibit lipidemic effects in rats similar to those of cocoa butter.

    Science.gov (United States)

    Rao, Reena; Lokesh, Belur R

    2003-09-01

    Lipase-catalyzed interesterification was used to prepare structured TG from coconut oil TG by partially replacing some of the atherogenic saturated FA with stearic acid, which is known to have a neutral effect on lipid levels in the body. The level of stearic acid was increased from 4% in the native coconut oil to 40% in the structured lipids, with most of the stearic acid being incorporated into the sn-1 and sn-3 positions of TG. When structured lipids were fed to rats at a 10% level for a period of 60 d, a 15% decrease in total cholesterol and a 23% decrease in LDL cholesterol levels in the serum were observed when compared to those fed coconut oil. Similarly, the total and free cholesterol levels in the livers of the rats fed structured lipids were lowered by 31 and 36%, respectively, when compared to those fed coconut oil. The TG levels in the serum and in the liver showed decreases of 14 and 30%, respectively, in animals fed structured lipids. Rats fed cocoa butter and structured lipids having a similar amount of stearic acid had similar lipid levels in the serum and liver. These studies indicated that the atherogenic potential of coconut oil lipids can be reduced significantly by enriching them with stearic acid. This also changed the physical properties of coconut oil closer to those of cocoa butter as determined by DSC.

  18. Ascorbic acid glycation of lens proteins produces UVA sensitizers similar to those in human lens

    International Nuclear Information System (INIS)

    Soluble calf lens proteins were extensively glycated during a 4 week incubation with ascorbic acid in the presence of oxygen. Amino acids analysis of the dialyzed proteins removed at weekly intervals showed an increasing loss of lysine, arginine and histidine, consistent with the extensive protein cross-linking observed. Irradiation of the dialyzed samples with UVA light (1.0 kJ/cm2 total illumination through a 338 nm cutoff filter) caused an increasing loss of tryptophan, an additional loss of histidine and the production of micromolar concentrations of hydrogen peroxide. No alteration in amino acid content and no photolytic effects were seen in proteins incubated without ascorbic acid in proteins incubated with glucose for 4 weeks. The rate of hydrogen peroxide formation was linear with each glycated sample with a maximum production of 25 nmol/mg protein illuminated. The possibility that the sensitizer activity was due to an ascorbate-induced oxidation of tryptophan was eliminated by the presence of a heavy metal ion chelator during the incubation and by showing equivalent effects with ascorbate-incubated ribonuclease A, which is devoid of tryptophan. The ascorbate-incubated samples displayed increasing absorbance at wavelengths above 300 nm and increasing fluorescence (340/430) as glycation proceeded. The spectra of the 4 week glycated proteins were identical to those obtained with a solubilized water-insoluble fraction from human lens, which is known to have UVA sensitizer activity. (Author)

  19. Physical and psychological stress have similar effects on gastric acid and pepsin secretions in rat

    Directory of Open Access Journals (Sweden)

    Ehsan Salimi

    2011-05-01

    Full Text Available Stress is one of the most important health and social problems. Previous studies have demonstrated stress influence on the clinical course of a number of gastrointestinal diseases, but its physical and psychological effects on gastric acid and pepsin secretions are largely unknown. 48 male wistar rats weighing 200-250 gr were used in this study. Animals were divided into 6 groups (n=8; Control, Physical stress, Psychological stress, L-NAME+ Physical stress and L-NAME+ Psychological stress groups. In this study, electrical shock generated in a communication box was used as physical shock and the emotional stress was as psychological stress.Gastric juice was collected by washout technique. Acid output was also measured by digital titrator. Gastric pepsin and nitric oxide (NO metabolites were quantified using Anson and Griess micro assay methods respectively.Basal and stimulated gastric acid and pepsin in physical and psychological stress groups were significantly more than others. NO metabolites level of gastric tissue in physical and psychological stress groups (286.9 ± 5.8, 287.7 ± 5.7 μmol/gr weight wet tissue, respectively were significantly more than other groups. But no significant differences among basal and stimulated gastric acid, pepsin and NO metabolites level were seen in physical and psychological stress groups.

  20. Efficiency of Gas-Phase Ion Formation in Matrix-Assisted Laser Desorption Ionization with 2,5-Dihydroxybenzoic Acid as Matrix

    International Nuclear Information System (INIS)

    Numbers of matrix- and analyte-derived ions and their sum in matrix-assisted laser desorption ionization (MALDI) of a peptide were measured using 2,5-dihydroxybenzoic acid (DHB) as matrix. As for MALDI with α-cyano-4-hydroxy cinnamic acid as matrix, the sum was independent of the peptide concentration in the solid sample, or was the same as that of pure DHB. This suggested that the matrix ion was the primary ion and that the peptide ion was generated by matrix-to-peptide proton transfer. Experimental ionization efficiencies of 10-5-10-4 for peptides and 10-8-10-7 for matrices are far smaller than 10.3-10.1 for peptides and 10-5-10-3 for matrices speculated by Hillenkamp and Karas. Number of gas-phase ions generated by MALDI was unaffected by laser wavelength or pulse energy. This suggests that the main role of photo-absorption in MALDI is not in generating ions via a multi-photon process but in ablating materials in a solid sample to the gas phase

  1. [Similarities, differences and agonisms of pleiotropic effects of statins and omega-3 fatty acids].

    Science.gov (United States)

    Villalobos, Maria E; Sánchez-Muniz, F J; Acín, Maria T; Vaquero, Maria P; Higueras, F J; Bastida, S

    2010-01-01

    This paper compares the pleiotropic effects of statins and omega-3 fatty acids (n-3 PUFA) in treating and preventing cardiovascular disease (CVD) and deals with the possible interactions of those compounds. Statins represent one of the most important discoveries to have been made in the field of cardiovascular medicine in recent decades. Their beneficial cardiovascular effects, which have reduced the number of fatal events in patients with atherosclerosis, encompass more than their ability to lower cholesterol levels. The pleiotropic effects of statins involve their anti-inflammatory and antiplatelet properties and their ability to normalize endothelial function. In addition, these drugs may display antiarrhythmic activity, improve insulin sensitivity and counteract hypertension and obesity. The low rate of coronary disease documented in Eskimos corroborates the cardioprotective effects of the n-3 PUFA eicosapentaenoic (EPA) and docosahexaenoic acids beyond their hypolipemic effects. The reduction of CVD-related deaths attributable to the action of α-linolenic fatty acid appears to be related to its strong antiarrhythmic properties. In addition, as a precursor of EPA and this last fatty acid of thromboxane A3, prostacyclin I3, serie-3 prostaglandines and serie 5-leukotrines and inhibitor/modulator of thromboxane A2, prostacyclin I2, serie-2 prostaglandines and serie 4-leukotrienes formation, the α-linolenic acid may reduce inflammation and thrombogenesis. As results of some studies suggest that the combined use of statins and n-3 PUFA improves cardiovascular protection and reduces the CVD-related mortality rate; the paper also reviews the possible synergism between both groups of compounds on CVD treatment and concludes that clear benefits may be obtained.

  2. A novel enzyme-based acidizing system: Matrix acidizing and drilling fluid damage removal

    Energy Technology Data Exchange (ETDEWEB)

    Harris, R.E.; McKay, D.M. [Cleansorb Limited, Surrey (United Kingdom); Moses, V. [King`s College, London (United Kingdom)

    1995-12-31

    A novel acidizing process is used to increase the permeability of carbonate rock cores in the laboratory and to remove drilling fluid damage from cores and wafers. Field results show the benefits of the technology as applied both to injector and producer wells.

  3. Arsenic speciation and identification of monomethylarsonous acid and monomethylthioarsonic acid in a complex matrix.

    Science.gov (United States)

    Yathavakilla, Santha Ketavarapu V; Fricke, Michael; Creed, Patricia A; Heitkemper, Douglas T; Shockey, Nohora V; Schwegel, Carol; Caruso, Joseph A; Creed, John T

    2008-02-01

    Anion-exchange chromatography was utilized for speciation of arsenite (As(III)), arsenate (As(V)), dimethylarsinic acid (DMA(V)), monomethylarsonic acid (MMA(V)), monomethylarsonous acid (MMA(III)), and the new As species monomethylthioarsonic acid (MMTA), using inductively coupled plasma mass spectrometric (ICPMS) detection. MMA(III) and MMTA were identified for the first time in freeze-dried carrot samples that were collected over 25 years ago as part of a joint U.S. EPA, U.S. FDA, and USDA study on trace elements in agricultural crops. The discovery of MMA(III) and MMTA in terrestrial foods necessitated the analytical characterization of synthetic standards of both species, which were used for standard addition in carrot extracts. The negative ion mode, high-resolution electrospray mass spectrometry (HR-ESI-MS) data produced molecular ions of m/z 122.9418 and 154.9152 for MMA(III) and MMTA, respectively. However, ESI-MS was not sensitive enough to directly identify MMA(III) and MMTA in the carrot extracts. Therefore, to further substantiate the identification of MMA(III) and MMTA, two additional separations using an Ion-120 column were developed using the more sensitive ICPMS detection. The first separation used 20 mM tetramethylammonium hydroxide at pH 12.2 with MMA(III) eluting in less than 7 min. In the second separation, MMTA eluted at 11.2 min by utilizing 40 mM ammonium carbonate at pH 9.0. Oxidation of MMA(III) and MMTA to MMA(V) with hydrogen peroxide was observed for standards and carrot extracts alike. Several samples of carrots collected from local markets in 2006 were also analyzed and found to contain low levels of inorganic arsenic species. PMID:18181583

  4. Hydrogen bond removal of pterin derivative whose structure is similar to nucleic acid bases.

    Science.gov (United States)

    Nonogawa, Mitsuru; Arai, Toshiyuki; Endo, Nobuyuki; Pack, Seung Pil; Kodaki, Tsutomu; Makino, Keisuke

    2005-01-01

    Pterin, an analog of guanine, is an electron transfer compound in biological systems. Among the analogs, 6-formylpterin (6FP) has been demonstrated to have many marked physiological and pharmacological activities and it is, therefore, worthwhile to elucidate whole mechanism of its activities. Unfortunately, however, 6FP is hardly soluble in water and organic solvents. Like nucleic acid bases, 6FP makes intermolecular hydrogen bonds and forms stacking structure causing such drawback nature. This has made mechanistic studies on 6FP activities extremely difficult. In this study, we carried out derivatization for 6FP and succeeded in increasing water solubility with maintaining its physiological activities. PMID:17150758

  5. The Expression of Bone Morphogenetic Protein 2 and Matrix Metalloproteinase 2 through Retinoic Acid Receptor Beta Induced by All-Trans Retinoic Acid in Cultured ARPE-19 Cells

    OpenAIRE

    Zhenya Gao; Lijun Huo; Dongmei Cui; Xiao Yang; Junwen Zeng

    2016-01-01

    Purpose All-trans retinoic acid (ATRA) plays an important role in ocular development. Previous studies found that retinoic acid could influence the metabolism of scleral remodeling by promoting retinal pigment epithelium (RPE) cells to secrete secondary signaling factors. The purpose of this study was to investigate whether retinoic acid affected secretion of bone morphogenetic protein 2 (BMP-2) and matrix metalloproteinase 2 (MMP-2) and to explore the signaling pathway of retinoic acid in cu...

  6. 37% Phosphoric Acid Induced Stronger Matrix Metalloproteinase-8 Expression of the Dental Pulp than 19% Ethylene Diamine Tetraacetic Acid

    Directory of Open Access Journals (Sweden)

    Nadie Fatimatuzzahro

    2014-11-01

    Full Text Available Etching agents such as ethylene diamine tetraacetic acid (EDTA and phosphoric acid which are widely used in adhesive restoration system aimed to increase for retention of restorative materials, may act a chemical irritant that induce inflammation of dental pulp. Inflammation is a body response against irritant and infectious agents. Matrix metalloproteinase-8, the major collagenolytic enzyme, degrades collagen type 1. This enzyme is expressed in low level in normal condition, however, the expression will increase during inflammation. The purpose of the present research was to study the effect of 19% EDTA and 37% phosphoric acid application as an etching agents on the MMP-8 expression of dental pulp. Forty-five male Sprague Dawley rats were divided into 3 groups. Cavity preparation was made on the occlusal surface of maxillary first molar using a round diamond bur. 19% EDTA, 37% phosphoric acid, and distilled water were applied on the surface of the cavity of the teeth in group I, II, and III subsequently. The cavity then filed by glass ionomer cements. The rats were sacrified at 1, 3, 5, 7, and 14 days after the treatment (n=3 for each day. The specimens were then processed histologically. Immunohistochemical (IHC analysis was performed using rabbit anti rat MMP-8 polyclonal antibody to examine MMP-8 expression and HE (Hematoxylen Eosin staining to observe the number of macrophages. The results showed 37% phosphoric acid application induced stronger expression of MMP-8 and higher number of macrophages than 19% EDTA. The strongest expression of MMP-8 seems on 5 days after the treatment where the highest number of macrophages were also found.

  7. Extracellular matrix assembly in extreme acidic eukaryotic biofilms and their possible implications in heavy metal adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Aguilera, Angeles [Centro de Astrobiologia (INTA-CSIC), Carretera de Ajalvir Km 4, Torrejon de Ardoz, 28850 Madrid (Spain)], E-mail: aguileraba@inta.es; Souza-Egipsy, Virginia [Centro de Astrobiologia (INTA-CSIC), Carretera de Ajalvir Km 4, Torrejon de Ardoz, 28850 Madrid (Spain); San Martin-Uriz, Patxi [Centro de Biologia Molecular (UAM-CSIC), Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Amils, Ricardo [Centro de Astrobiologia (INTA-CSIC), Carretera de Ajalvir Km 4, Torrejon de Ardoz, 28850 Madrid (Spain); Centro de Biologia Molecular (UAM-CSIC), Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain)

    2008-07-30

    To evaluate the importance of the extracellular matrix in relation to heavy metal binding capacity in extreme acidic environments, the extracellular polymeric substances (EPS) composition of 12 biofilms isolated from Rio Tinto (SW, Spain) was analyzed. Each biofilm was composed mainly by one or two species of eukaryotes, although other microorganisms were present. EPS ranged from 130 to 439 mg g{sup -1} biofilm dry weight, representing between 15% and the 40% of the total biofilm dry weight (DW). Statistically significant differences (p < 0.05) were found in the amount of total EPS extracted from biofilms dominated by the same organism at different sampling points. The amount of EPS varied among different biofilms collected from the same sampling location. Colloidal EPS ranged from 42 to 313 mg g{sup -1} dry weight; 10% to 30% of the total biofilm dry weight. Capsular EPS ranged from 50 to 318 mg g{sup -1} dry weight; 5% to 30% of the total biofilm dry weight. Seven of the 12 biofilms showed higher amounts of capsular than colloidal EPS (p < 0.05). Total amount of EPS decreased when total cell numbers and pH increased. There was a positive correlation between EPS concentration and heavy metal concentration in the water. Observations by low temperature scanning electron microscopy (LTSEM) revealed the mineral adsorption in the matrix of EPS and onto the cell walls. EPS in all biofilms were primarily composed of carbohydrates, heavy metals and humic acid, plus small quantities of proteins and DNA. After carbohydrates, heavy metals were the second main constituents of the extracellular matrix. Their total concentrations ranged from 3 to 32 mg g{sup -1} biofilm dry weight, reaching up to 16% of the total composition. In general, the heavy metal composition of the EPS extracted from the biofilms closely resembled the metal composition of the water from which the biofilms were collected.

  8. In vitro toxicity of carbon nanotubes, nano-graphite and carbon black, similar impacts of acid functionalization.

    Science.gov (United States)

    Figarol, Agathe; Pourchez, Jérémie; Boudard, Delphine; Forest, Valérie; Akono, Céline; Tulliani, Jean-Marc; Lecompte, Jean-Pierre; Cottier, Michèle; Bernache-Assollant, Didier; Grosseau, Philippe

    2015-12-25

    Carbon nanotubes (CNT) and nano-graphite (NG) are graphene-based nanomaterials which share exceptional physicochemical properties, but whose health impacts are unfortunately still not well understood. On the other hand, carbon black (CB) is a conventional and widely studied material. The comparison of these three carbon-based nanomaterials is thus of great interest to improve our understanding of their toxicity. An acid functionalization was carried out on CNT, NG and CB so that, after a thorough characterization, their impacts on RAW 264.7 macrophages could be compared for a similar surface chemistry (15 to 120 μg·mL(-1) nanomaterials, 90-min to 24-h contact). Functionalized nanomaterials triggered a weak cytotoxicity similar to the pristine nanomaterials. Acid functionalization increased the pro-inflammatory response except for CB which did not trigger any TNF-α production before or after functionalization, and seemed to strongly decrease the oxidative stress. The toxicological impact of acid functionalization appeared thus to follow a similar trend whatever the carbon-based nanomaterial. At equivalent dose expressed in surface and equivalent surface chemistry, the toxicological responses from murine macrophages to NG were higher than for CNT and CB. It seemed to correspond to the hypothesis of a platelet and fiber paradigm.

  9. 谱聚类图像分割中相似度矩阵构造研究%Research on Similarity Matrix Structure in Spectral Clustering Image Segmentation

    Institute of Scientific and Technical Information of China (English)

    李扬; 陆璐; 崔红霞

    2016-01-01

    In recent years,spectral clustering algorithm is widely used in the field of image segmentation,and the structure of the similarity matrix is the key of it. When the color images are segmented by traditional spectral clustering algorithm,the only one of color space and distance calculation formula is usually used to construct similarity matrix. The influence of the segmentation results established on the dif-ferent color space and distance calculation formula is neglected,which leads to many limitations of spectral clustering algorithm. To solve this problem,using the formula of Euclidean distance,cosine distance and chi square distance,the different similarity matrices are estab-lished on RGB and HSV color space. The best segmentation construction method of the similarity matrix is obtained by analysis and com-parison of the effect of different construction methods. The effectiveness of spectral clustering algorithm for segmenting color images is improved. By calculating the accuracy of image segmentation results and the performance evaluation index of precision and recall,the reli-ability and accuracy of the experiment are verified.%近年来谱聚类算法广泛应用于图像分割领域,而相似度矩阵的构造是谱聚类算法的关键。通常传统的谱聚类算法分割彩色图像时,仅采用一种颜色空间和距离计算公式构造相似度矩阵,而忽略了不同的颜色空间和距离计算公式构造的相似度矩阵对分割结果的影响,导致谱聚类算法有诸多的局限性。针对这个问题,文中分别采用RGB和HSV颜色空间,以及分别在两种颜色空间下使用欧氏距离、余弦距离和卡方距离公式,建立不同的相似度矩阵。分析比较不同构造方法的分割效果,得出了最优分割效果的相似度矩阵构造方法,提高了应用谱聚类算法分割彩色图像的有效性。通过计算性能评价指标查准率和查全率以及分割结果的准确率,验证

  10. 4-Chloro-α-cyanocinnamic acid is an efficient soft matrix for cyanocobalamin detection in foodstuffs by matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS).

    Science.gov (United States)

    Calvano, Cosima Damiana; Ventura, Giovanni; Palmisano, Francesco; Cataldi, Tommaso R I

    2016-09-01

    4-Chloro-α-cyanocinnamic acid (ClCCA) is a very useful matrix able to give the protonated adduct [M+H](+) of intact cyanocobalamin (CNCbl) as the base peak (m/z 1355.58) in matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS). The only fragment observed is [M-CN + H](+•) formed through the facile (•) CN neutral loss reflecting the fairly low Co-C bond energy. All other investigated proton transfer matrices, including α-cyano-4-hydroxycinnamic acid, para-nitroaniline and 2,5-dihydroxybenzoic acid, give rise to a complete decyanation of CNCbl with concomitant formation of [M-CN + H](+•) , [M-CN + Na](+•) and [M-CN + K](+•) adducts at m/z 1329.57, 1351.55 and 1367.51, respectively. Depending on the matrix used, a variable degree of fragmentation involving the α-side axial ligand was observed. A plausible explanation of the specific behaviour of 4-chloro-α-cyanocinnamic acid as a soft matrix is discussed. Tandem mass spectra of both [M + H](+) and [M-CN + H](+•) ions were obtained and product ions successfully assigned. The possibility of detecting the protonated adduct of intact CNCbl was exploited in foodstuff samples such as cow milk and hen egg yolk by MALDI tandem MS upon sample extraction. We believe that our data provide strong basis for the application of MALDI tandem MS in the qualitative analysis of natural CNCbl, including fish, liver and meat samples. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27468135

  11. 4-Chloro-α-cyanocinnamic acid is an efficient soft matrix for cyanocobalamin detection in foodstuffs by matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS).

    Science.gov (United States)

    Calvano, Cosima Damiana; Ventura, Giovanni; Palmisano, Francesco; Cataldi, Tommaso R I

    2016-09-01

    4-Chloro-α-cyanocinnamic acid (ClCCA) is a very useful matrix able to give the protonated adduct [M+H](+) of intact cyanocobalamin (CNCbl) as the base peak (m/z 1355.58) in matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS). The only fragment observed is [M-CN + H](+•) formed through the facile (•) CN neutral loss reflecting the fairly low Co-C bond energy. All other investigated proton transfer matrices, including α-cyano-4-hydroxycinnamic acid, para-nitroaniline and 2,5-dihydroxybenzoic acid, give rise to a complete decyanation of CNCbl with concomitant formation of [M-CN + H](+•) , [M-CN + Na](+•) and [M-CN + K](+•) adducts at m/z 1329.57, 1351.55 and 1367.51, respectively. Depending on the matrix used, a variable degree of fragmentation involving the α-side axial ligand was observed. A plausible explanation of the specific behaviour of 4-chloro-α-cyanocinnamic acid as a soft matrix is discussed. Tandem mass spectra of both [M + H](+) and [M-CN + H](+•) ions were obtained and product ions successfully assigned. The possibility of detecting the protonated adduct of intact CNCbl was exploited in foodstuff samples such as cow milk and hen egg yolk by MALDI tandem MS upon sample extraction. We believe that our data provide strong basis for the application of MALDI tandem MS in the qualitative analysis of natural CNCbl, including fish, liver and meat samples. Copyright © 2016 John Wiley & Sons, Ltd.

  12. Hypohalous acids contribute to renal extracellular matrix damage in experimental diabetes.

    Science.gov (United States)

    Brown, Kyle L; Darris, Carl; Rose, Kristie Lindsey; Sanchez, Otto A; Madu, Hartman; Avance, Josh; Brooks, Nickolas; Zhang, Ming-Zhi; Fogo, Agnes; Harris, Raymond; Hudson, Billy G; Voziyan, Paul

    2015-06-01

    In diabetes, toxic oxidative pathways are triggered by persistent hyperglycemia and contribute to diabetes complications. A major proposed pathogenic mechanism is the accumulation of protein modifications that are called advanced glycation end products. However, other nonenzymatic post-translational modifications may also contribute to pathogenic protein damage in diabetes. We demonstrate that hypohalous acid-derived modifications of renal tissues and extracellular matrix (ECM) proteins are significantly elevated in experimental diabetic nephropathy. Moreover, diabetic renal ECM shows diminished binding of α1β1 integrin consistent with the modification of collagen IV by hypochlorous (HOCl) and hypobromous acids. Noncollagenous (NC1) hexamers, key connection modules of collagen IV networks, are modified via oxidation and chlorination of tryptophan and bromination of tyrosine residues. Chlorotryptophan, a relatively minor modification, has not been previously found in proteins. In the NC1 hexamers isolated from diabetic kidneys, levels of HOCl-derived oxidized and chlorinated tryptophan residues W(28) and W(192) are significantly elevated compared with nondiabetic controls. Molecular dynamics simulations predicted a more relaxed NC1 hexamer tertiary structure and diminished assembly competence in diabetes; this was confirmed using limited proteolysis and denaturation/refolding. Our results suggest that hypohalous acid-derived modifications of renal ECM, and specifically collagen IV networks, contribute to functional protein damage in diabetes.

  13. Correction of Tear Trough Deformity With a Cohesive Polydensified Matrix Hyaluronic Acid: A Case Series.

    Science.gov (United States)

    Huber-Vorländer, Jürgen; Kürten, Martin

    2015-01-01

    The tear trough or infraorbital hollow is a challenging area to treat, and only a few fillers are suitable for this delicate area. We report on a European case series of six subjects with mild to severe tear troughs who received treatment with cohesive polydensified matrix (CPM®) technology hyaluronic acid gel (Belotero® Balance). The product was injected as small depots (up to ten small boli 0.2 mL maximum each per side) at the supraperiosteal level along or below the orbital rim. Follow-up visits took place at 1, 3, 6, and 9 months after injection for independent evaluation of the clinical effect using the Merz Aesthetics Scale™ for infraorbital hollows and the Global Aesthetic Improvement Scale. Adverse events were also recorded. Mean hollowness scores were considerably improved compared with baseline in all subjects. In all women, the improvements remained throughout the 9-month study, with none reverting to their baseline score. Subjects' satisfaction with treatment was very high throughout the study, and all women stated that they would repeat treatment with the same product. The CPM hyaluronic acid gel was well tolerated. CPM hyaluronic acid gel is a safe and effective treatment for the tear trough area. PMID:26605822

  14. Molecular surface area based predictive models for the adsorption and diffusion of disperse dyes in polylactic acid matrix.

    Science.gov (United States)

    Xu, Suxin; Chen, Jiangang; Wang, Bijia; Yang, Yiqi

    2015-11-15

    Two predictive models were presented for the adsorption affinities and diffusion coefficients of disperse dyes in polylactic acid matrix. Quantitative structure-sorption behavior relationship would not only provide insights into sorption process, but also enable rational engineering for desired properties. The thermodynamic and kinetic parameters for three disperse dyes were measured. The predictive model for adsorption affinity was based on two linear relationships derived by interpreting the experimental measurements with molecular structural parameters and compensation effect: ΔH° vs. dye size and ΔS° vs. ΔH°. Similarly, the predictive model for diffusion coefficient was based on two derived linear relationships: activation energy of diffusion vs. dye size and logarithm of pre-exponential factor vs. activation energy of diffusion. The only required parameters for both models are temperature and solvent accessible surface area of the dye molecule. These two predictive models were validated by testing the adsorption and diffusion properties of new disperse dyes. The models offer fairly good predictive ability. The linkage between structural parameter of disperse dyes and sorption behaviors might be generalized and extended to other similar polymer-penetrant systems.

  15. The shell matrix of the freshwater mussel Unio pictorum (Paleoheterodonta, Unionoida). Involvement of acidic polysaccharides from glycoproteins in nacre mineralization.

    Science.gov (United States)

    Marie, Benjamin; Luquet, Gilles; Pais De Barros, Jean-Paul; Guichard, Nathalie; Morel, Sylvain; Alcaraz, Gérard; Bollache, Loïc; Marin, Frédéric

    2007-06-01

    Among molluscs, the shell biomineralization process is controlled by a set of extracellular macromolecular components secreted by the calcifying mantle. In spite of several studies, these components are mainly known in bivalves from only few members of pteriomorph groups. In the present case, we investigated the biochemical properties of the aragonitic shell of the freshwater bivalve Unio pictorum (Paleoheterodonta, Unionoida). Analysis of the amino acid composition reveals a high amount of glycine, aspartate and alanine in the acid-soluble extract, whereas the acid-insoluble one is rich in alanine and glycine. Monosaccharidic analysis indicates that the insoluble matrix comprises a high amount of glucosamine. Furthermore, a high ratio of the carbohydrates of the soluble matrix is sulfated. Electrophoretic analysis of the acid-soluble matrix revealed discrete bands. Stains-All, Alcian Blue, periodic acid/Schiff and autoradiography with (45)Ca after electrophoretic separation revealed three major polyanionic calcium-binding glycoproteins, which exhibit an apparent molecular mass of 95, 50 and 29 kDa, respectively. Two-dimensional gel electrophoresis shows that these bands, provisionally named P95, P50 and P29, are composed of numerous isoforms, the majority of which have acidic isoelectric points. Chemical deglycosylation of the matrix with trifluoromethanesulfonic acid induces a drastic shift of both the apparent molecular mass and the isoelectric point of these matrix components. This treatment induces also a modification of the shape of CaCO(3) crystals grown in vitro and a loss of the calcium-binding ability of two of the main matrix proteins (P95 and P50). Our findings strongly suggest that post-translational modifications display important functions in mollusc shell calcification.

  16. The shell matrix of the freshwater mussel Unio pictorum (Paleoheterodonta, Unionoida). Involvement of acidic polysaccharides from glycoproteins in nacre mineralization.

    Science.gov (United States)

    Marie, Benjamin; Luquet, Gilles; Pais De Barros, Jean-Paul; Guichard, Nathalie; Morel, Sylvain; Alcaraz, Gérard; Bollache, Loïc; Marin, Frédéric

    2007-06-01

    Among molluscs, the shell biomineralization process is controlled by a set of extracellular macromolecular components secreted by the calcifying mantle. In spite of several studies, these components are mainly known in bivalves from only few members of pteriomorph groups. In the present case, we investigated the biochemical properties of the aragonitic shell of the freshwater bivalve Unio pictorum (Paleoheterodonta, Unionoida). Analysis of the amino acid composition reveals a high amount of glycine, aspartate and alanine in the acid-soluble extract, whereas the acid-insoluble one is rich in alanine and glycine. Monosaccharidic analysis indicates that the insoluble matrix comprises a high amount of glucosamine. Furthermore, a high ratio of the carbohydrates of the soluble matrix is sulfated. Electrophoretic analysis of the acid-soluble matrix revealed discrete bands. Stains-All, Alcian Blue, periodic acid/Schiff and autoradiography with (45)Ca after electrophoretic separation revealed three major polyanionic calcium-binding glycoproteins, which exhibit an apparent molecular mass of 95, 50 and 29 kDa, respectively. Two-dimensional gel electrophoresis shows that these bands, provisionally named P95, P50 and P29, are composed of numerous isoforms, the majority of which have acidic isoelectric points. Chemical deglycosylation of the matrix with trifluoromethanesulfonic acid induces a drastic shift of both the apparent molecular mass and the isoelectric point of these matrix components. This treatment induces also a modification of the shape of CaCO(3) crystals grown in vitro and a loss of the calcium-binding ability of two of the main matrix proteins (P95 and P50). Our findings strongly suggest that post-translational modifications display important functions in mollusc shell calcification. PMID:17488282

  17. Utilizing cell-matrix interactions to modulate gene transfer to stem cells inside hyaluronic acid hydrogels.

    Science.gov (United States)

    Gojgini, Shiva; Tokatlian, Talar; Segura, Tatiana

    2011-10-01

    The effective delivery of DNA locally would increase the applicability of gene therapy in tissue regeneration, where diseased tissue is to be repaired in situ. One promising approach is to use hydrogel scaffolds to encapsulate and deliver plasmid DNA in the form of nanoparticles to the diseased tissue, so that cells infiltrating the scaffold are transfected to induce regeneration. This study focuses on the design of a DNA nanoparticle-loaded hydrogel scaffold. In particular, this study focuses on understanding how cell-matrix interactions affect gene transfer to adult stem cells cultured inside matrix metalloproteinase (MMP) degradable hyaluronic acid (HA) hydrogel scaffolds. HA was cross-linked to form a hydrogel material using a MMP degradable peptide and Michael addition chemistry. Gene transfer inside these hydrogel materials was assessed as a function of polyplex nitrogen to phosphate ratio (N/P = 5 to 12), matrix stiffness (100-1700 Pa), RGD (Arg-Gly-Asp) concentration (10-400 μM), and RGD presentation (0.2-4.7 RGDs per HA molecule). All variables were found to affect gene transfer to mouse mensenchymal stem cells culture inside the DNA loaded hydrogels. As expected, higher N/P ratios lead to higher gene transfer efficiency but also higher toxicity; softer hydrogels resulted in higher transgene expression than stiffer hydrogels, and an intermediate RGD concentration and RGD clustering resulted in higher transgene expression. We believe that the knowledge gained through this in vitro model can be utilized to design better scaffold-mediated gene delivery for local gene therapy.

  18. Science of Hyaluronic Acid Beyond Filling: Fibroblasts and Their Response to the Extracellular Matrix.

    Science.gov (United States)

    Landau, Marina; Fagien, Steven

    2015-11-01

    Loss of viscoelasticity is one of the primarily signs of skin aging, followed by appearance of visible wrinkles. Hyaluronic acid (HA)-based fillers are widely used to fill wrinkles and compensate for volume loss. Recent clinical observations demonstrate persistence of the filling effect longer than the biological availability of the filler. Stimulation of new collagen by cross-linked HA and up-regulation of elastin have been suggested as possible explanation to this observation and have been supported experimentally. Cross-linked HA substitutes for fragmented collagen in restoring extracellular matrix required for normal activity of fibroblasts, such as collagen and elastin production. To restore extracellular matrix efficiently, serial monthly treatments are required. Boosting of facial and nonfacial skin through fibroblast activation is a new indication for HA-based products. Injectable HA has also been recently registered in Europe as agents specific for the improvement of skin quality (Restylane Skinboosters). Further explanation of the possible mechanisms supported by long-term clinical examples is presented herein. PMID:26441098

  19. Fluorometric quantification of polyphosphate in environmental plankton samples: extraction protocols, matrix effects, and nucleic acid interference.

    Science.gov (United States)

    Martin, Patrick; Van Mooy, Benjamin A S

    2013-01-01

    Polyphosphate (polyP) is a ubiquitous biochemical with many cellular functions and comprises an important environmental phosphorus pool. However, methodological challenges have hampered routine quantification of polyP in environmental samples. We tested 15 protocols to extract inorganic polyphosphate from natural marine samples and cultured cyanobacteria for fluorometric quantification with 4',6-diamidino-2-phenylindole (DAPI) without prior purification. A combination of brief boiling and digestion with proteinase K was superior to all other protocols, including other enzymatic digestions and neutral or alkaline leaches. However, three successive extractions were required to extract all polyP. Standard addition revealed matrix effects that differed between sample types, causing polyP to be over- or underestimated by up to 50% in the samples tested here. Although previous studies judged that the presence of DNA would not complicate fluorometric quantification of polyP with DAPI, we show that RNA can cause significant interference at the wavelengths used to measure polyP. Importantly, treating samples with DNase and RNase before proteinase K digestion reduced fluorescence by up to 57%. We measured particulate polyP along a North Pacific coastal-to-open ocean transect and show that particulate polyP concentrations increased toward the open ocean. While our final method is optimized for marine particulate matter, different environmental sample types may need to be assessed for matrix effects, extraction efficiency, and nucleic acid interference.

  20. Oxidizing gel formulation for nuclear decontamination: rheological and acidic properties of the organic matrix and its ozonolysis

    International Nuclear Information System (INIS)

    An acidic and oxidizing gel was formulated with a purely organic matrix, xanthan gum, at low concentrations (1 to 2 wt %). This polymer gel was investigated in various media (aqueous, acidic and ceric) by means of rheology: shear thinning behaviour, thixotropy, yield stress... Evidences of unexpected rheological properties in highly concentrated media show that xanthan is quite convenient for industrial projection of this type of gel on metallic walls in nuclear plants, notwithstanding its time-limited resistance to oxidation (about a few hours). Complexation mechanisms between ceric species and polar sites of the polymer led us to characterise acidic properties of our xanthan sample by potentiometric titration and 1H NMR techniques. The matrix was finally treated by ozonolysis to suppress organic residues, as required to handle nuclear wastes. In acidic medium, ozonolysis of the gel was achieved successfully while in acidic and ceric medium this process showed limited efficiency, needing further investigation to be clarified. (author)

  1. Evaluation of Influence of Various Polymers on Dissolution and Phase Behavior of Carbamazepine-Succinic Acid Cocrystal in Matrix Tablets

    Directory of Open Access Journals (Sweden)

    Majeed Ullah

    2015-01-01

    Full Text Available The aim of current study was to explore the influence of three commonly used polymers, that is, cellulosics and noncellulosics, for example, Methocel K4M, Kollidon VA/64, and Soluplus, on the phase disproportionation and drug release profile of carbamazepine-succinic acid (CBZ-SUC cocrystal at varying drug to polymer ratios (1 : 1 to 1 : 0.25 in matrix tablets. The polymorphic phase disproportionation during in-depth dissolution studies of CBZ-SUC cocrystals and its crystalline properties were scrutinized by X-ray powder diffractrometry and Raman spectroscopy. The percent drug release from HPMC formulations (CSH showed inverse relation with the concentration of polymer; that is, drug release increased with decrease in polymer concentration. On contrary, direct relation was observed between percent drug release and polymer concentrations of Kollidon VA 64/Soluplus (CSK, CSS. At similar polymer concentration, drug release from pure carbamazepine was slightly lower with HPMC formulations than that of cocrystal; however, opposite trend in release rate was observed with Kollidon VA/64 and Soluplus. The significant increase in dissolution rate of cocrystal occurred with Kollidon VA/64 and Soluplus at higher polymer concentration. Moreover, no phase change took place in Methocel and Kollidon formulations. No tablet residue was left for Soluplus formulation so the impact of polymer on cocrystal integrity cannot be predicted.

  2. Rapid HPLC analysis of amino acids and biogenic amines in wines during fermentation and evaluation of matrix effect.

    Science.gov (United States)

    Wang, Ya-Qin; Ye, Dong-Qing; Zhu, Bao-Qing; Wu, Guang-Feng; Duan, Chang-Qing

    2014-11-15

    A rapid HPLC method has been developed for the simultaneous determination of 23 amino acids, 10 biogenic amines and the ammonium ion in wine. Samples were pre-column derivatised with diethyl ethoxymethylenemalonate and separated using reversed-phase HPLC within 30 min. The matrix effect was evaluated when measuring samples taken from different stages of fermentation. Most compounds showed no obvious matrix effect, whereas proline, ethanolamine and spermine had remarkably different responses to variable concentrations of sugar. High concentrations of sugar affected the pH of the derivatisation reaction system; proline, ethanolamine and spermine derivatives were sensitive to this effect. Matrix-matched calibration was used for the quantification of these compounds. Validation of the method showed that it was accurate, reproducible and efficient for the simultaneous determination of amino acids and biogenic amines in wines during fermentation. As a specific application of the method, red wine samples taken from different stages of fermentation were analysed. PMID:24912689

  3. Similarities Across Mars: Acidic Fluids at Both Meridiani Planum and Gale Crater in the Formation of Magnesium-Nickel Sulfates

    Science.gov (United States)

    Yen, Albert S.; Ming, Douglas W.; Gellert, Ralf; Mittlefehldt, David W.; Vaniman, David T.; Thompson, Lucy M.; Morris, Richard V.; Clark, Benton C.; Arvidson, Raymond

    2016-01-01

    In-situ identification of sulfates at the martian surface by the Mars Exploration Rovers and the Mars Science Laboratory have included calcium sulfates with various states of hydration (gypsum, bassanite, anhydrite), iron sulfates of likely fumarolic origin, massive deposits of iron hydroxysulfates indicative of an acidic history, and minor occurrences of magnesium sulfates. Recent measurements by the Opportunity and Curiosity Alpha Particle X-ray Spectrometers (APXS) have indicated the presence of Ni-substituted Mg-sulfates at the Meridiani Planum and Gale Crater landing sites. The Opportunity rover has traversed nearly 43 km and is currently exploring the impact breccias of the rim of Endeavour crater, near a location where signatures of aqueous alteration have been established from orbit. APXS analyses of subsurface materials excavated by a rover wheel show clear evidence for a Mg(Ni)-sulfate with Mg:Ni (is) approximately 100:1 (molar). On the other side of the planet, Curiosity is continuing its climb up Mount Sharp after driving (is) approximately 13 km since landing. Over the last 4 km of the traverse, there have been multiple chemical analyses of erosionally-resistant nodules and dendritic features in a finely laminated mudstone unit which also indicate Mg(Ni)-sulfate (Mg:Ni (is) approximately 30:1, molar). The geologic settings for the Endeavour rim and the Mount Sharp mudstones are clearly different, but similar formation conditions for these sulfates may be possible. Ni(2+) readily substitutes for Mg(2+) in a variety of geochemical processes due to their comparable ionic radii. The availability of soluble Ni at the time of Mg-sulfate precipitation suggests acidic solutions. The fluids responsible for alteration in the Endeavour rim and for the formation of nodules in Gale mudstones may have had similar chemical characteristics at the time the Mg-sulfates were formed.

  4. Inhibition of matrix metalloproteinases expression in human dental pulp cells by all-trans retinoic acid

    Institute of Scientific and Technical Information of China (English)

    Jin Man Kim; Sang Wook Kang; Su-Mi Shin; Duck Su Kim; Kyong-Kyu Choi; Eun-Cheol Kim; Sun-Young Kim

    2014-01-01

    All-trans retinoic acid (ATRA) inhibits matrix metalloproteinase (MMP)-2 and MMP-9 in synovial fibroblasts, skin fibroblasts, bronchoalveolar lavage cells and cancer cells, but activates MMP-9 in neuroblast and leukemia cells. Very little is known regarding whether ATRA can activate or inhibit MMPs in human dental pulp cells (HDPCs). The purpose of this study was to determine the effects of ATRA on the production and secretion of MMP-2 and-9 in HDPCs. The productions and messenger RNA (mRNA) expressions of MMP-2 and-9 were accessed by gelatin zymography and real-time polymerase chain reaction (PCR), respectively. ATRA was found to decrease MMP-2 level in a dose-dependent manner. Significant reduction in MMP-2 mRNA expression was also observed in HDPCs treated with 25 mmol?L21 ATRA. However, HDPCs treated with ATRA had no effect on the pattern of MMP-9 produced or secreted in either cell extracts or conditioned medium fractions. Taken together, ATRA had an inhibitory effect on MMP-2 expression in HDPCs, which suggests that ATRA could be a candidate as a medicament which could control the inflammation of pulp tissue in vital pulp therapy and regenerative endodontics.

  5. Electrochemical biosensing platform using hydrogel prepared from ferrocene modified amino acid as highly efficient immobilization matrix.

    Science.gov (United States)

    Qu, Fengli; Zhang, Yi; Rasooly, Avraham; Yang, Minghui

    2014-01-21

    To increase the loading of glucose oxidase (GOx) and simplify glucose biosensor fabrication, hydrogel prepared from ferrocene (Fc) modified amino acid phenylalanine (Phe, F) was utilized for the incorporation of GOx. The synthesized hydrogel displays good biocompatibility and contains a significant number of Fc moieties, which can be considered as an ideal matrix to immobilize enzymes for the preparation of mediator-based biosensors. The hydrogel was studied by scanning electron microscopy, which indicated that it was composed of nanofibers with a diameter of around 50-100 nm and length extended to 1 mm. With the addition of GOx into the hydrogel and by directly dropping the resulting biocomposite onto the electrode surface, a glucose biosensor, that displays good performance due to improved enzyme loading and efficient electron transfer, can be simply constructed. The favorable network structure and good biocompatibility of the hydrogel could effectively avoid enzyme leakage and maintain the bioactivity of the enzymes, which resulted in good stability of the biosensor. The biosensor was utilized for the detection of glucose in blood samples with results comparable to those obtained from the hospital. The hydrogel as a functional component of an amperometric biosensor has implications for future development of biosensors and for clinical applications. PMID:24383679

  6. Hydrophobic silica nanoparticles as reinforcing filler for poly (lactic acid polymer matrix

    Directory of Open Access Journals (Sweden)

    Pilić Branka M.

    2016-01-01

    Full Text Available Properties of poly (lactic acid (PLA and its nanocomposites, with silica nanoparticles (SiO2, as filler were investigated. Neat PLA films and PLA films with different percentage of hydrophobic fumed silica nanoparticles (0.2, 0.5, 1, 2, 3 and 5 wt. % were prepared by solution casting method. Several tools were used to characterize the influence of different silica content on crystalline behavior, and thermal, mechanical and barrier properties of PLA/SiO2 nanocomposites. Results from scanning electron microscope (SEM showed that the nanocomposite preparation and selection of specific hydrophobic spherical nano filler provide a good dispersion of the silica nanoparticles in the PLA matrix. Addition of silica nanoparticles improved mechanical properties, the most significant improvement being observed for lowest silica content (0.2wt.%. Barrier properties were improved for all measured gases at all loadings of silica nanoparticles. The degree of crystallinity for PLA slightly increased by adding 0.2 and 0.5 wt. % of nano filler. [Projekat Ministarstva nauke Republike Srbije, br. III46001

  7. Similarity of the yellow chromophores isolated from human cataracts with those from ascorbic acid-modified calf lens proteins: evidence for ascorbic acid glycation during cataract formation.

    Science.gov (United States)

    Cheng, R; Lin, B; Lee, K W; Ortwerth, B J

    2001-07-27

    Chromatographic evidence supporting the similarity of the yellow chromophores isolated from aged human and brunescent cataract lenses and calf lens proteins ascorbylated in vitro is presented. The water-insoluble fraction from early stage brunescent cataract lenses was solubilized by sonication (WISS) and digested with a battery of proteolytic enzymes under argon to prevent oxidation. Also, calf lens proteins were incubated with ascorbic acid for 4 weeks in air and submitted to the same digestion. The percent hydrolysis of the proteins to amino acids was approximately 90% in every case. The content of yellow chromophores was 90, 130 and 250 A(330) units/g protein for normal human WISS, cataract WISS and ascorbate-modified bovine lens proteins respectively. Aliquots equivalent to 2.0 g of digested protein were subjected to size-exclusion chromatography on a Bio-Gel P-2 column. Six peaks were obtained for both preparations and pooled. Side by side thin-layer chromatography (TLC) of each peak showed very similar R(f) values for the long wavelength-absorbing fluorophores. Glycation with [U-(14)C]ascorbic acid, followed by digestion and Bio-Gel P-2 chromatography, showed that the incorporated radioactivity co-eluted with the A(330)-absorbing peaks, and that most of the fluorescent bands were labeled after TLC. Peaks 2 and 3 from the P-2 were further fractionated by preparative Prodigy C-18 reversed-phase high-performance liquid chromatography. Two major A(330)-absorbing peaks were seen in peak 2 isolated from human cataract lenses and 5 peaks in fraction 3, all of which eluted at the same retention times as those from ascorbic acid glycated calf lens proteins. HPLC fractionation of P-2 peaks 4, 5 and 6 showed many A(330)-absorbing peaks from the cataract WISS, only some of which were identical to the asorbylated proteins. The major fluorophores, however, were present in both preparations. These data provide new evidence to support the hypothesis that the yellow

  8. Similar peptides from two beta cell autoantigens, proinsulin and glutamic acid decarboxylase, stimulate T cells of individuals at risk for insulin-dependent diabetes.

    OpenAIRE

    Rudy, G; N. Stone; Harrison, L C; Colman, P. G.; McNair, P; Brusic, V.; French, M. B.; Honeyman, M. C.; Tait, B.; Lew, A M

    1995-01-01

    BACKGROUND: Insulin (1) and glutamic acid decarboxylase (GAD) (2) are both autoantigens in insulin-dependent diabetes mellitus (IDDM), but no molecular mechanism has been proposed for their association. We have identified a 13 amino acid peptide of proinsulin (amino acids 24-36) that bears marked similarity to a peptide of GAD65 (amino acids 506-518) (G. Rudy, unpublished). In order to test the hypothesis that this region of similarity is implicated in the pathogenesis of IDDM, we assayed T c...

  9. Effects of ultraviolet irradiation on bonding strength between Co-Cr alloy and citric acid-crosslinked gelatin matrix.

    Science.gov (United States)

    Inoue, Motoki; Sasaki, Makoto; Katada, Yasuyuki; Taguchi, Tetsushi

    2014-02-01

    Novel techniques for creating a strong bond between polymeric matrices and biometals are required. We immobilized polymeric matrices on the surface of biometal for drug-eluting stents through covalent bond. We performed to improve the bonding strength between a cobalt-chromium alloy and a citric acid-crosslinked gelatin matrix by ultraviolet irradiation on the surface of cobalt-chromium alloy. The ultraviolet irradiation effectively generated hydroxyl groups on the surface of the alloy. The bonding strength between the gelatin matrix and the alloy before ultraviolet irradiation was 0.38 ± 0.02 MPa, whereas it increased to 0.48 ± 0.02 MPa after ultraviolet irradiation. Surface analysis showed that the citric acid derivatives occurred on the surface of the cobalt-chromium alloy through ester bond. Therefore, ester bond formation between the citric acid derivatives active esters and the hydroxyl groups on the cobalt-chromium alloy contributed to the enhanced bonding strength. Ultraviolet irradiation and subsequent immobilization of a gelatin matrix using citric acid derivatives is thus an effective way to functionalize biometal surfaces.

  10. Similar PAH fate in anaerobic digesters inoculated with three microbial communities accumulating either volatile fatty acids or methane.

    Directory of Open Access Journals (Sweden)

    Florence Braun

    Full Text Available Urban sludge produced on wastewater treatment plants are often contaminated by organic pollutants such as polycyclic aromatic hydrocarbons (PAH. Their removal under methanogenic conditions was already reported, but the factors influencing this removal remain unclear. Here, we determined the influence of microbial communities on PAH removal under controlled physico-chemical conditions. Twelve mesophilic anaerobic digesters were inoculated with three microbial communities extracted from ecosystems with contrasting pollution histories: a PAH contaminated soil, a PCB contaminated sediment and a low contaminated anaerobic sludge. These anaerobic digesters were operated during 100 days in continuous mode. A sterilised activated sludge, spiked with 13 PAH at concentrations usually encountered in full-scale wastewater treatment plants, was used as substrate. The dry matter and volatile solid degradation, the biogas production rate and composition, the volatile fatty acids (VFA production and the PAH removals were monitored. Bacterial and archaeal communities were compared in abundance (qPCR, in community structure (SSCP fingerprinting and in dominant microbial species (454-pyrosequencing. The bioreactors inoculated with the community extracted from low contaminated anaerobic sludge showed the greater methane production. The PAH removals ranged from 10% to 30%, respectively, for high and low molecular weight PAH, whatever the inoculums tested, and were highly correlated with the dry matter and volatile solid removals. The microbial community structure and diversity differed with the inoculum source; this difference was maintained after the 100 days of digestion. However, the PAH removal was not correlated to these diverse structures and diversities. We hence obtained three functional stable consortia with two contrasted metabolic activities, and three different pictures of microbial diversity, but similar PAH and matter removals. These results confirm

  11. Protective effect of naringin on 3-nitropropionic acid-induced neurodegeneration through the modulation of matrix metalloproteinases and glial fibrillary acidic protein.

    Science.gov (United States)

    Gopinath, Kulasekaran; Sudhandiran, Ganapasam

    2016-01-01

    Naringin (4',5,7-trihydroxy-flavonone-7-rhamnoglucoside), a flavonone present in grapefruit, has recently been reported to protect against neurodegeration, induced with 3-nitropropionic acid (3-NP), through its antioxidant, anti-inflammatory, and antiapoptotic properties. This study used a rat model of 3-NP-induced neurodegeneration to investigate the neuroprotective effects of naringin exerted by modulating the expression of matrix metalloproteinases and glial fibrillary acidic protein. Neurodegeneration was induced with 3-NP (10 mg/kg body mass, by intraperitoneal injection) once a day for 2 weeks, and induced rats were treated with naringin (80 mg/kg body mass, by oral gavage, once a day for 2 weeks). Naringin ameliorated the motor abnormalities caused by 3-NP, and reduced blood-brain barrier dysfunction by decreasing the expression of matrix metalloproteinases 2 and 9, along with increasing the expression of the tissue inhibitors of metalloproteinases 1 and 2 in 3-NP-induced rats. Further, naringin reduced 3-NP-induced neuroinflammation by decreasing the expression of nuclear factor-kappa B and glial fibrillary acidic protein. Thus, naringin exerts protective effects against 3-NP-induced neurodegeneration by ameliorating the expressions of matrix metalloproteinases and glial fibrillary acidic protein. PMID:26544788

  12. Delivery of Polyunsaturated Fatty Acids from a Glycerol Polyester Matrix with Anti-oxidant Properties

    Science.gov (United States)

    Awareness of the health benefits associated with the polyunsaturated acids such as alpha linolenic (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), has generated interest in formulating foods and dietary supplements with these compounds. However, the highly unsaturated structure o...

  13. Wnt/β-Catenin and Retinoic Acid Receptor Signaling Pathways Interact to Regulate Chondrocyte Function and Matrix Turnover*

    OpenAIRE

    Yasuhara, Rika; Yuasa, Takahito; Williams, Julie A.; Byers, Stephen W.; Shah, Salim; Pacifici, Maurizio; Iwamoto, Masahiro; Enomoto-Iwamoto, Motomi

    2009-01-01

    Activation of the Wnt/β-catenin and retinoid signaling pathways is known to tilt cartilage matrix homeostasis toward catabolism. Here, we investigated possible interactions between these pathways. We found that all-trans-retinoic acid (RA) treatment of mouse epiphyseal chondrocytes in culture did increase Wnt/β-catenin signaling in the absence or presence of exogenous Wnt3a, as revealed by lymphoid enhancer factor/T-cell factor/β-catenin reporter activity and β-catenin nuclear accumulation. T...

  14. Synthesis of silica coated zinc oxide–poly(ethylene-co-acrylic acid) matrix and its UV shielding evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Ramasamy, Mohankandhasamy [Division of Bionanotechnology, Gachon University, Seongnam 461-701 (Korea, Republic of); Kim, Yu Jun; Gao, Haiyan [Department of Polymer Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Yi, Dong Kee, E-mail: vitalis@mju.ac.kr [Department of Chemistry, Myongji University, Yongin 449-728 (Korea, Republic of); An, Jeong Ho, E-mail: jhahn1us@skku.edu [Department of Polymer Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2014-03-01

    Graphical abstract: - Highlights: • Well layer thickness controlled silica shell was made on ZnO nanoparticles. • PEAA, an interfacial agent is used to make nanocomposite–polymer matrix by twin-screw extruder. • Si-ZnO/PEAA matrix is highly stable and UV protective as compared to ZnO/PEAA matrix. • Nanoparticle embedded polymer matrix is suggested to make UV shielding fabrics with Nylon4. - Abstract: Silica coated zinc oxide nanoparticles (Si-ZnO NPs) (7 nm thick) were synthesized successfully and melt blended with poly(ethylene-co-acrylic acid) (PEAA resin) to improving ultraviolet (UV) shielding of zinc oxide nanoparticles (ZnO NPs). The photostability of both the ZnO NPs and Si-ZnO NPs were analyzed by the difference in photoluminescence (PL) and by methylene blue (MB) degradation. Photo-degradation studies confirmed that Si-ZnO NPs are highly photostable compared to ZnO NPs. The melt blended matrices were characterized by field emission scanning electron microscopy interfaced with energy dispersive X-ray spectroscopy (FE-SEM-EDX). The UV shielding property was analyzed from the transmittance spectra of UV–visible (UV–vis) spectroscopy. The results confirmed fine dispersion of thick Si-ZnO NPs in the entire resin matrix. Moreover, the Si-ZnO/PEAA showed about 97% UV shielding properties than the ZnO/PEAA.

  15. Analysis of the relationship between genomic GC Content and patterns of base usage, codon usage and amino acid usage in prokaryotes: similar GC content adopts similar compositional frequencies regardless of the phylogenetic lineages.

    Directory of Open Access Journals (Sweden)

    Hui-Qi Zhou

    Full Text Available The GC contents of 2670 prokaryotic genomes that belong to diverse phylogenetic lineages were analyzed in this paper. These genomes had GC contents that ranged from 13.5% to 74.9%. We analyzed the distance of base frequencies at the three codon positions, codon frequencies, and amino acid compositions across genomes with respect to the differences in the GC content of these prokaryotic species. We found that although the phylogenetic lineages were remote among some species, a similar genomic GC content forced them to adopt similar base usage patterns at the three codon positions, codon usage patterns, and amino acid usage patterns. Our work demonstrates that in prokaryotic genomes: a base usage, codon usage, and amino acid usage change with GC content with a linear correlation; b the distance of each usage has a linear correlation with the GC content difference; and c GC content is more essential than phylogenetic lineage in determining base usage, codon usage, and amino acid usage. This work is exceptional in that we adopted intuitively graphic methods for all analyses, and we used these analyses to examine as many as 2670 prokaryotes. We hope that this work is helpful for understanding common features in the organization of microbial genomes.

  16. Radiation-induced transformations of matrix-isolated formic acid: evidence for the HCOOH → HOCO + H channel.

    Science.gov (United States)

    Ryazantsev, Sergey V; Feldman, Vladimir I

    2015-11-11

    The effect of X-ray irradiation on the isolated formic acid molecules (HCOOH) in solid noble gas matrices (Xe, Kr, Ar, and Ne) at very low temperatures (6 K) was first studied by FTIR spectroscopy. Carbon oxides (CO and CO2) and hydrocarboxyl radicals (HOCO) have been detected as the principal degradation products. The formation of HOCO radicals represents a primary dissociation channel for formic acid, which was not reported previously under UV photolysis in solids. This reaction can be explained by the involvement of the recombination-induced excited states, which are not populated in photolysis. The effects of the matrix and the absorbed dose on the product formation were studied in detail and possible mechanisms are discussed with particular attention to the difference between radiolysis and UV-photolysis of the matrix-isolated formic acid. The results obtained provide a new insight into the effects of high-energy impact on the simplest carboxylic acid with possible implications to the astrochemical problems, in particular, the prebiotic evolution in the interstellar medium. PMID:26524429

  17. Electrochemical sensor for dopamine based on imprinted silica matrix-poly(aniline boronic acid) hybrid as recognition element.

    Science.gov (United States)

    Li, Jian; Zhang, Ning; Sun, Qingqing; Bai, Zhanming; Zheng, Jianbin

    2016-10-01

    A novel imprinted silica matrix-poly(aniline boronic acid) hybrid for electrochemical detection of dopamine (DA) was developed. Boronic acid functionalized conducting polymer was electrochemically prepared on Au electrode. The number of covalent binding sites toward DA templates was controlled by potential cycles. A precursory sol solution of ammonium fluorosilicate (as cross-linking monomer) containing DA was spin-coated on the polymer modified electrode. Under NH3 atmosphere, the hydroxyl ions were generated in the solution and catalyzed the hydrolysis of fluorosilicate to form silica matrix. After this aqueous sol-gel process, an inorganic framework around the DA template was formed and the imprinted hybrid for DA was also produced. As revealed by scanning electron microscopy, UV-vis spectroscopy and cyclic voltammetry characterization, DA was embedded in the imprinted hybrid successfully. The affinity and selectivity of the imprinted hybrid were also characterized by cyclic voltammetry. The imprinted hybrid showed higher affinity for DA than that for epinephrine, and little or no affinity for ascorbic acid and uric acid due to the combined effects of covalent interaction, cavities matching and electrostatic repulsion. The imprinted hybrid sensor exhibited a quick response (within 5min) to DA in the concentration range from 0.05 to 500μmolL(-1) with a detection limit of 0.018μmolL(-1). The prepared sensor was also applied to detect DA in real samples with a satisfactory result. PMID:27474321

  18. Strategies for the elimination of matrix effects in the LC-MS/MS analysis of the lipophilic toxins okadaic acid and azaspiracid-1 in molluscan shellfish

    OpenAIRE

    Kilcoyne, Jane; Fux, Elie

    2010-01-01

    Considerable efforts are being made worldwide to replace in vivo assays with instrumental methods of analysis for the monitoring of marine biotoxins in shellfish. Analysis of these compounds by the preferred technique of LC-MS/MS is challenged by matrix effects associated with shellfish tissue components. In methods validation, assessment of matrix interferences is imperative to ensure the accuracy of analytical results. We evaluated matrix interferences in the analysis of okadaic acid (OA)...

  19. Quantitative analysis of highly similar salvianolic acids with (1)H qNMR for quality control of traditional Chinese medicinal preparation Salvianolate Lyophilized Injection.

    Science.gov (United States)

    Chen, Xialin; Guo, Yujie; Hu, Yuanjia; Yu, Boyang; Qi, Jin

    2016-05-30

    Salvianolate Lyophilized Injection (SLI), a traditional Chinese medicinal (TCM) preparation which is used to treat stroke, is composed of multiple salvianolic acids from the aqueous extracts of Salvia miltiorrhiza, and includes mainly protocatechualdehyde, rosmarinic acid, salvianolic acid B, salvianolic acid D, salvianolic acid E, diastereomer of salvianolic acid E, salvianolic acid Y, lithospermic acid and diastereomer of lithospermic acid. It is difficult to quantitatively control the quality of SLI using traditional high performance liquid chromatography due to the highly similar structure of these constituents including three pairs of diastereomers and the lack of commercial resources for most of these constituents as standards. Thus, a highly reproducible, fast, accurate and simple (1)H quantitative nuclear magnetic resonance (qNMR) method without the need for calibration curves and complex computation was established by optimizing the solvent system and acquisition parameters to simultaneously determine the nine salvianolic acids and mannitol in SLI. This method was validated and successfully used to determine 10 batches of SLI and the qNMR data were further analyzed with a vector including angle cosine and the partial least squares method for the quality control of SLI. The results indicated that qNMR can be used as a routine method for the quality control of SLI and may have potential in the quantification of diastereomers in other TCM preparations. PMID:26970983

  20. Trends for isolated amino acids and dipeptides: Conformation, divalent ion binding, and remarkable similarity of binding to calcium and lead

    CERN Document Server

    Ropo, Matti; Baldauf, Carsten

    2016-01-01

    We derive structural and binding energy trends for twenty amino acids, their dipeptides, and their interactions with the divalent cations Ca$^{2+}$, Ba$^{2+}$, Sr$^{2+}$, Cd$^{2+}$, Pb$^{2+}$, and Hg$^{2+}$. The underlying data set consists of 45,892 first-principles predicted conformers with relative energies up to about 4 eV (about 400kJ/mol). We show that only very few distinct backbone structures of isolated amino acids and their dipeptides emerge as lowest-energy conformers. The isolated amino acids predominantly adopt structures that involve an acidic proton shared between the carboxy and amino function. Dipeptides adopt one of two intramolecular-hydrogen bonded conformations C$_5$ or equatorial C$_7$. Upon complexation with a divalent cation, the accessible conformational space shrinks and intramolecular hydrogen bonding is prevented due to strong electrostatic interaction of backbone and side chain functional groups with cations. Clear correlations emerge from the binding energies of the six divalent ...

  1. Unitary Congruence and Unitary Similarity for Quaternion Matrix%四元数矩阵的酉相合与酉相似

    Institute of Scientific and Technical Information of China (English)

    蔡永裕; 黄礼平

    2009-01-01

    This paper discusses the unitary congruence of quaternion matrices, the uni-tary congruence of quaternion matrices is natural extension of the complex unitary congruence of complex matrices and has many good properties. Since unitary congruence of quaternion matrices is in connection with unitary similarity of quaternion matrices, we also discuss some properties of the unitary similarity of quaternion matrices.%本文讨论了四元数矩阵的酉相合,四元数矩阵的酉相合是复矩阵的复酉相合的自然推广,并且它有许多好的性质.由于四元数矩阵的酉相合与酉相似有着密切联系,本文还讨论了四元数矩阵的酉相似的一些性质.

  2. Pore formation mechanism of porous poly(DL-lactic acid) matrix membrane.

    Science.gov (United States)

    Phaechamud, Thawatchai; Chitrattha, Sasiprapa

    2016-04-01

    Porous PLA structure has been widely used in cell transplantation, drug carrier and wound dressing. The porous structure can be controlled depending on the choice of the polymer, solvent, nonsolvent and preparation parameters. In this study, the porous PLA matrix membranes were prepared by adding PEG 400 in PLA solution using dichloromethane (DCM) as solvent prior to casting. The influence of other liquids as co-solvent on pore formation and the structural change during membrane formation were evaluated. The co-solvents affected both porous topography and mechanical properties of PLA membrane. The porous matrix were produced when the non-solvent of PLA was used as co-solvent. Cryo-SEM micrographs revealed that PEG 400 still remained in the PLA porous matrix membrane. From the tracking of the structural change during film formation, the PLA-PEG solution changed into porous structure by liquid liquid phase separation and solidification processes, respectively. Thermogravimetric analysis revealed that PLA-PEG in DCM solution exhibited the two-step of weight loss, the first step occurred from DCM evaporation and the second step occurred from the degradation of PLA-PEG matrix. The liquid-liquid phase separation and solidification started when the amount of DCM was higher than PEG 400 for 2.67 folds and DCM amount was equal to that of PEG 400, respectively. These results could clarify the pore formation mechanism of porous PLA membrane and will be useful for the further investigation and application. PMID:26838905

  3. Studies Related to the Oregon State University High Temperature Test Facility: Scaling, the Validation Matrix, and Similarities to the Modular High Temperature Gas-Cooled Reactor

    International Nuclear Information System (INIS)

    The Oregon State University (OSU) High Temperature Test Facility (HTTF) is an integral experimental facility that will be constructed on the OSU campus in Corvallis, Oregon. The HTTF project was initiated, by the U.S. Nuclear Regulatory Commission (NRC), on September 5, 2008 as Task 4 of the 5 year High Temperature Gas Reactor Cooperative Agreement via NRC Contract 04-08-138. Until August, 2010, when a DOE contract was initiated to fund additional capabilities for the HTTF project, all of the funding support for the HTTF was provided by the NRC via their cooperative agreement. The U.S. Department of Energy (DOE) began their involvement with the HTTF project in late 2009 via the Next Generation Nuclear Plant project. Because the NRC interests in HTTF experiments were only centered on the depressurized conduction cooldown (DCC) scenario, NGNP involvement focused on expanding the experimental envelope of the HTTF to include steady-state operations and also the pressurized conduction cooldown (PCC). Since DOE has incorporated the HTTF as an ingredient in the NGNP thermal-fluids validation program, several important outcomes should be noted: (1) The reference prismatic reactor design, that serves as the basis for scaling the HTTF, became the modular high temperature gas-cooled reactor (MHTGR). The MHTGR has also been chosen as the reference design for all of the other NGNP thermal-fluid experiments. (2) The NGNP validation matrix is being planned using the same scaling strategy that has been implemented to design the HTTF, i.e., the hierarchical two-tiered scaling methodology developed by Zuber in 1991. Using this approach a preliminary validation matrix has been designed that integrates the HTTF experiments with the other experiments planned for the NGNP thermal-fluids verification and validation project. (3) Initial analyses showed that the inherent power capability of the OSU infrastructure, which only allowed a total operational facility power capability of 0.6 MW

  4. Studies Related to the Oregon State University High Temperature Test Facility: Scaling, the Validation Matrix, and Similarities to the Modular High Temperature Gas-Cooled Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Richard R. Schultz; Paul D. Bayless; Richard W. Johnson; William T. Taitano; James R. Wolf; Glenn E. McCreery

    2010-09-01

    The Oregon State University (OSU) High Temperature Test Facility (HTTF) is an integral experimental facility that will be constructed on the OSU campus in Corvallis, Oregon. The HTTF project was initiated, by the U.S. Nuclear Regulatory Commission (NRC), on September 5, 2008 as Task 4 of the 5 year High Temperature Gas Reactor Cooperative Agreement via NRC Contract 04-08-138. Until August, 2010, when a DOE contract was initiated to fund additional capabilities for the HTTF project, all of the funding support for the HTTF was provided by the NRC via their cooperative agreement. The U.S. Department of Energy (DOE) began their involvement with the HTTF project in late 2009 via the Next Generation Nuclear Plant project. Because the NRC interests in HTTF experiments were only centered on the depressurized conduction cooldown (DCC) scenario, NGNP involvement focused on expanding the experimental envelope of the HTTF to include steady-state operations and also the pressurized conduction cooldown (PCC). Since DOE has incorporated the HTTF as an ingredient in the NGNP thermal-fluids validation program, several important outcomes should be noted: 1. The reference prismatic reactor design, that serves as the basis for scaling the HTTF, became the modular high temperature gas-cooled reactor (MHTGR). The MHTGR has also been chosen as the reference design for all of the other NGNP thermal-fluid experiments. 2. The NGNP validation matrix is being planned using the same scaling strategy that has been implemented to design the HTTF, i.e., the hierarchical two-tiered scaling methodology developed by Zuber in 1991. Using this approach a preliminary validation matrix has been designed that integrates the HTTF experiments with the other experiments planned for the NGNP thermal-fluids verification and validation project. 3. Initial analyses showed that the inherent power capability of the OSU infrastructure, which only allowed a total operational facility power capability of 0.6 MW, is

  5. Diglycolamic acid anchored on polyamine matrix for the mutual separation of Eu(III) and Am(III)

    Energy Technology Data Exchange (ETDEWEB)

    Suneesh, A.S.; Syamala, K.V.; Venkatesan, K.A.; Antony, M.P.; Vasudeva Rao, P.R. [Indira Gandhi Centre for Atomic Research, Kalpakkam (India). Fuel Chemistry Div.

    2016-04-01

    Diglycolamic acid was anchored on a polyamine matrix and the product (PA-DGAH) was characterized by ion-exchange capacity measurement, TG-DTA and FT-IR spectroscopy. The extraction behavior of Am(III) and Eu(III) in PA-DGAH was studied from dilute nitric acid medium to examine the feasibility using the anchored adsorbent for their mutual separation. The effect of various parameters such as the duration of equilibration, concentration of europium, nitric acid and diethylenetriaminepentaacetic acid (DTPA) in aqueous phase on the distribution coefficient (K{sub d}) of Am(III) and Eu(III) was studied. The distribution coefficient decreased with increase in the concentration of nitric acid. Rapid extraction of metal ions in the initial stages of equilibration followed by the establishment of equilibrium occurred within 4 h. The data on the rate of uptake of Am(III) and Eu(III) were fitted into pseudo-first order and pseudo-second order rate equation. The extraction isotherm was fitted to Langmuir and Freundlich adsorption models and the apparent europium extraction capacity was determined. The mechanism of extraction was elucidated and the conditions needed for efficient separation of Am(III) from Eu(III) was optimized using DTPA. The study indicated the possibility of using PA-DGAH for the separation of Eu(III) from Am(III) with high separation factors.

  6. Nonlinear optical studies on 4-(ferrocenylmethylimino)-2-hydroxy-benzoic acid thin films deposited by matrix-assisted pulsed laser evaporation (MAPLE)

    Science.gov (United States)

    Matei, Andreea; Marinescu, Maria; Constantinescu, Catalin; Ion, Valentin; Mitu, Bogdana; Ionita, Iulian; Dinescu, Maria; Emandi, Ana

    2016-06-01

    We present results on a new, laboratory synthesized ferrocene-derivative, i.e. 4-(ferrocenylmethylimino)-2-hydroxy-benzoic acid. Thin films with controlled thickness are deposited by matrix-assisted pulsed laser evaporation (MAPLE), on quartz and silicon substrates, with the aim of evaluating the nonlinear optical properties for potential optoelectronic applications. Dimethyl sulfoxide was used as matrix, with 1% wt. concentration of the guest compound. The frozen target is irradiated by using a Nd:YAG laser (4ω/266 nm, 7 ns pulse duration, 10 Hz repetition rate), at low fluences ranging from 0.1 to 1 J/cm2. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) are used to probe the surface morphology of the films. Fourier transform infrared (FTIR) and Raman spectroscopy reveal similar structure of the thin film material when compared to the starting material. The optical properties of the thin films are investigated by spectroscopic-ellipsometry (SE), and the refractive index dependence with respect to temperature is studied. The second harmonic generation (SHG) potential is assessed by using a femtosecond Ti:sapphire laser (800 nm, 60-100 fs pulse duration, 80 MHz repetition rate), at 200 mW maximum output power, revealing that the SHG signal intensity is strongly influenced by the films' thickness.

  7. Negative Ion In-Source Decay Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry for Sequencing Acidic Peptides

    Science.gov (United States)

    McMillen, Chelsea L.; Wright, Patience M.; Cassady, Carolyn J.

    2016-05-01

    Matrix-assisted laser desorption/ionization (MALDI) in-source decay was studied in the negative ion mode on deprotonated peptides to determine its usefulness for obtaining extensive sequence information for acidic peptides. Eight biological acidic peptides, ranging in size from 11 to 33 residues, were studied by negative ion mode ISD (nISD). The matrices 2,5-dihydroxybenzoic acid, 2-aminobenzoic acid, 2-aminobenzamide, 1,5-diaminonaphthalene, 5-amino-1-naphthol, 3-aminoquinoline, and 9-aminoacridine were used with each peptide. Optimal fragmentation was produced with 1,5-diaminonphthalene (DAN), and extensive sequence informative fragmentation was observed for every peptide except hirudin(54-65). Cleavage at the N-Cα bond of the peptide backbone, producing c' and z' ions, was dominant for all peptides. Cleavage of the N-Cα bond N-terminal to proline residues was not observed. The formation of c and z ions is also found in electron transfer dissociation (ETD), electron capture dissociation (ECD), and positive ion mode ISD, which are considered to be radical-driven techniques. Oxidized insulin chain A, which has four highly acidic oxidized cysteine residues, had less extensive fragmentation. This peptide also exhibited the only charged localized fragmentation, with more pronounced product ion formation adjacent to the highly acidic residues. In addition, spectra were obtained by positive ion mode ISD for each protonated peptide; more sequence informative fragmentation was observed via nISD for all peptides. Three of the peptides studied had no product ion formation in ISD, but extensive sequence informative fragmentation was found in their nISD spectra. The results of this study indicate that nISD can be used to readily obtain sequence information for acidic peptides.

  8. Investigating the use of coupling agents to improve the interfacial properties between a resorbable phosphate glass and polylactic acid matrix.

    Science.gov (United States)

    Hasan, Muhammad Sami; Ahmed, Ifty; Parsons, Andrew J; Rudd, Chris D; Walker, Gavin S; Scotchford, Colin A

    2013-09-01

    Eight different chemicals were investigated as potential candidate coupling agents for phosphate glass fibre reinforced polylactic acid composites. Evidence of reaction of the coupling agents with phosphate glass and their effect on surface wettability and glass degradation were studied along with their principle role of improving the interface between glass reinforcement and polymer matrix. It was found that, with an optimal amount of coupling agent on the surface of the glass/polymer, interfacial shear strength improved by a factor of 5. Evidence of covalent bonding between agent and glass was found for three of the coupling agents investigated, namely: 3-aminopropyltriethoxysilane; etidronic acid and hexamethylene diisocyanate. These three coupling agents also improved the interfacial shear strength and increased the hydrophobicity of the glass surface. It is expected that this would provide an improvement in the macroscopic properties of full-scale composites fabricated from the same materials which may also help to retain these properties for the desired length of time by retarding the breakdown of the fibre/matrix interface within these composites.

  9. Biosynthesis of monoterpenoids in higher plants. The biosynthetic pathway leading to the monoterpenoids from amino acids with a carbon-skeleton similar to mevalonic acid

    Energy Technology Data Exchange (ETDEWEB)

    Tange, K. (Hiroshima Univ. (Japan). Faculty of Science)

    1981-09-01

    Radioisotopically labeled L-valine, DL-alanine, sodium acetate, and DL-mevalonic acid were incorporated into linalool by the intact plant of Cinnamomum camphora Sieb. var. linalooliferum Fujita and into geraniol and citronellol by that of Pelargonium roseum Bourbon. The uptake of leucine and valine resulted in the preferential location of the radioactivity on the 3,3-dimethylallyl pyrophosphate-derived moiety of these acyclic monoterpenoids, whereas the uptake of alanine resulted in the preferential location on the isopentenyl pyrophosphate-derived moiety, much as in the cases of mevalonic acid and sodium acetate. A biosynthetic pathway leading to the monoterpenoids from the amino acids is discussed.

  10. Matrix Domain Modulates HIV-1 Gag's Nucleic Acid Chaperone Activity via Inositol Phosphate Binding ▿

    OpenAIRE

    Jones, Christopher P.; Datta, Siddhartha A.K.; Rein, Alan; Rouzina, Ioulia; Musier-Forsyth, Karin

    2010-01-01

    Retroviruses replicate by reverse transcribing their single-stranded RNA genomes into double-stranded DNA using specific cellular tRNAs to prime cDNA synthesis. In HIV-1, human tRNA3Lys serves as the primer and is packaged into virions during assembly. The viral Gag protein is believed to chaperone tRNA3Lys placement onto the genomic RNA primer binding site; however, the timing and possible regulation of this event are currently unknown. Composed of the matrix (MA), capsid (CA), nucleocapsid ...

  11. Detection of single amino acid mutation in human breast cancer by disordered plasmonic self-similar chain

    KAUST Repository

    Coluccio, M. L.

    2015-09-04

    Control of the architecture and electromagnetic behavior of nanostructures offers the possibility of designing and fabricating sensors that, owing to their intrinsic behavior, provide solutions to new problems in various fields. We show detection of peptides in multicomponent mixtures derived from human samples for early diagnosis of breast cancer. The architecture of sensors is based on a matrix array where pixels constitute a plasmonic device showing a strong electric field enhancement localized in an area of a few square nanometers. The method allows detection of single point mutations in peptides composing the BRCA1 protein. The sensitivity demonstrated falls in the picomolar (10−12 M) range. The success of this approach is a result of accurate design and fabrication control. The residual roughness introduced by fabrication was taken into account in optical modeling and was a further contributing factor in plasmon localization, increasing the sensitivity and selectivity of the sensors. This methodology developed for breast cancer detection can be considered a general strategy that is applicable to various pathologies and other chemical analytical cases where complex mixtures have to be resolved in their constitutive components.

  12. Spectrophotometric method for fast quantification of ascorbic acid and dehydroascorbic acid in simple matrix for kinetics measurements.

    Science.gov (United States)

    Gómez Ruiz, Braulio; Roux, Stéphanie; Courtois, Francis; Bonazzi, Catherine

    2016-11-15

    A simple, rapid and reliable method was developed for quantifying ascorbic (AA) and dehydroascorbic (DHAA) acids and validated in 20mM malate buffer (pH 3.8). It consists in a spectrophotometric measurement of AA, either directly on the solution added with metaphosphoric acid or after reduction of DHAA into AA by dithiothreitol. This method was developed with real time measurement of reactions kinetics in bulk reactors in mind, and was checked in terms of linearity, limits of detection and quantification, fidelity and accuracy. The linearity was found satisfactory on the range of 0-6.95mM with limits of detection and quantification of 0.236mM and 0.467mM, respectively. The method was found acceptable in terms of fidelity and accuracy with a coefficient of variation for repeatability and reproducibility below 6% for AA and below 15% for DHAA, and with a recovery range of 97-102% for AA and 88-112% for DHAA. PMID:27283671

  13. Stearic acid and high molecular weight PEO as matrix for the highly water soluble metoprolol tartrate in continuous twin-screw melt granulation.

    Science.gov (United States)

    Monteyne, Tinne; Adriaensens, Peter; Brouckaert, Davinia; Remon, Jean-Paul; Vervaet, Chris; De Beer, Thomas

    2016-10-15

    Granules with release-sustaining properties were developed by twin screw hot melt granulation (HMG) using a combination of stearic acid (SA) and high molecular weight polyethylene oxide (PEO) as matrix for a highly water soluble model drug, metoprolol tartrate (MPT). Earlier studies demonstrated that mixing molten SA and PEO resulted in hydrogen bond formation between hydroxyl groups of fatty acid molecules and ether groups in PEO chains. These molecular interactions might be beneficial in order to elevate the sustained release effect of drugs from a SA/PEO matrix. This study aims to investigate the continuous twin screw melt granulation technique to study the impact of a SA/PEO matrix on the dissolution rate of a highly water soluble drug (MPT). Decreasing the SA/PEO ratio improved the release-sustaining properties of the matrix. The solid state of the granules was characterized using differential scanning calorimetry (DSC), nuclear magnetic resonance (NMR), X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FTIR) and near infrared chemical imaging (NIR-CI) in order to understand the dissolution behavior. The results revealed a preferential interaction of the MPT molecules with stearic acid impeding the PEO to form hydrogen bonds with the stearic acid chains. However, this allowed the PEO chains to recrystallize inside the stearic acid matrix after granulation, hence, elevating the release-sustaining characteristics of the formulation. PMID:27452420

  14. Identification of Protein-Protein Interactions via a Novel Matrix-Based Sequence Representation Model with Amino Acid Contact Information.

    Science.gov (United States)

    Ding, Yijie; Tang, Jijun; Guo, Fei

    2016-01-01

    Identification of protein-protein interactions (PPIs) is a difficult and important problem in biology. Since experimental methods for predicting PPIs are both expensive and time-consuming, many computational methods have been developed to predict PPIs and interaction networks, which can be used to complement experimental approaches. However, these methods have limitations to overcome. They need a large number of homology proteins or literature to be applied in their method. In this paper, we propose a novel matrix-based protein sequence representation approach to predict PPIs, using an ensemble learning method for classification. We construct the matrix of Amino Acid Contact (AAC), based on the statistical analysis of residue-pairing frequencies in a database of 6323 protein-protein complexes. We first represent the protein sequence as a Substitution Matrix Representation (SMR) matrix. Then, the feature vector is extracted by applying algorithms of Histogram of Oriented Gradient (HOG) and Singular Value Decomposition (SVD) on the SMR matrix. Finally, we feed the feature vector into a Random Forest (RF) for judging interaction pairs and non-interaction pairs. Our method is applied to several PPI datasets to evaluate its performance. On the S . c e r e v i s i a e dataset, our method achieves 94 . 83 % accuracy and 92 . 40 % sensitivity. Compared with existing methods, and the accuracy of our method is increased by 0 . 11 percentage points. On the H . p y l o r i dataset, our method achieves 89 . 06 % accuracy and 88 . 15 % sensitivity, the accuracy of our method is increased by 0 . 76 % . On the H u m a n PPI dataset, our method achieves 97 . 60 % accuracy and 96 . 37 % sensitivity, and the accuracy of our method is increased by 1 . 30 % . In addition, we test our method on a very important PPI network, and it achieves 92 . 71 % accuracy. In the Wnt-related network, the accuracy of our method is increased by 16 . 67 % . The source code and all datasets are available

  15. Structure of isothiocyanic acid dimers. Theoretical and FTIR matrix isolation studies

    Science.gov (United States)

    Krupa, Justyna; Wierzejewska, Maria

    2016-05-01

    A quantum mechanical study of the potential energy surface for the HNCS dimer is reported. The calculations were performed using DFT and ab initio MP2 methods. The most stable is a cyclic form with a double N-H⋯S interaction and the interaction energy in the range of 16.91-18.92 kJ mol-1. An open HNCS dimer bound by the N-H⋯N hydrogen bond is by ca 3.3-5.1 kJ mol-1 less stable. Experimental FTIR matrix isolation studies of HNCS/N2 system show that exclusively less stable open dimer is formed in solid nitrogen. Possible reasons for the observed discrepancy between theory and experiment are discussed.

  16. Effects of spray-drying on w/o/w multiple emulsions prepared from a stearic acid matrix.

    Science.gov (United States)

    Mlalila, Nichrous; Swai, Hulda; Kalombo, Lonji; Hilonga, Askwar

    2014-01-01

    The goal of this study was to explore the effects of spray-drying on w/o/w double emulsions of methyltestosterone (MT) loaded in a stearic acid matrix. MT-loaded nanoparticles were formulated by a water-in-oil-in-water emulsion technique using 50, 75, and 100 mg of stearic acid, 2% and 3% w/v polyvinyl alcohol, 5% w/v lactose, and 0.2% w/v chitosan. The emulsions were immediately spray-dried based on an optimized model of inlet temperature and pump rate, and characterized for optimized responses with regard to particle size, polydispersity index, and zeta potential, for both emulsion and powder samples. Dynamic light scattering analysis shown that the nanoparticles increased in size with increasing concentrations of polyvinyl alcohol and stearic acid. Scanning electron microscopy indicated that the MT-loaded nanoparticles were spherical in shape, had a smooth surface, and were in an amorphous state, which was confirmed by differential scanning calorimetry. These MT-loaded nanoparticles are a promising candidate carrier for the delivery of MT; however, further studies are needed in order to establish the stability of the system and the cargo release profile under normal conditions of use. PMID:25489238

  17. Towards Acid-Tolerated Ethanol Dehydration: Chitosan-Based Mixed Matrix Membranes Containing Cyano-Bridged Coordination Polymer Nanoparticles.

    Science.gov (United States)

    Wu, C-W; Kang, Chao-Hsiang; Lin, Yi-Feng; Tung, Kuo-Lun; Deng, Yu-Heng; Ahamad, Tansir; Alshehri, Saad M; Suzuki, Norihiro; Yamauchi, Yusuke

    2016-04-01

    Prussian blue (PB) nanoparticles, one of many cyano-bridged coordination polymers, are successfully incorporated into chitosan (CS) polymer to prepare PB/CS mixed matrix membranes (MMMs). The PB nanoparticles are uniformly distributed in the MMMs without the collapse of the original PB structure. As-prepared PB/CS MMMs are used for ethanol dehydration at 25 °C in the pervaporation process. The effect of loading PB in CS matrix on pervaporation performance is carefully investigated. The PB/CS membrane with 30 wt% PB loading shows the best performance with a permeate flux of 614 g. m-2 . h-1 and a separation factor of 1472. The pervaporation using our PB/CS membranes exhibits outstanding performance in comparison with the previously reported CS-based membranes and MMMs. Furthermore, the addition of PB allows PB/CS MMMs to be tolerant of acidic environment. The present work demonstrates good pervaporation performance of PB/CS MMMs for the separation of an ethanol/water (90:10 in wt%) solution. Our new system provides an opportunity for dehydration of bioethanol in the future. PMID:27451778

  18. Towards Acid-Tolerated Ethanol Dehydration: Chitosan-Based Mixed Matrix Membranes Containing Cyano-Bridged Coordination Polymer Nanoparticles.

    Science.gov (United States)

    Wu, C-W; Kang, Chao-Hsiang; Lin, Yi-Feng; Tung, Kuo-Lun; Deng, Yu-Heng; Ahamad, Tansir; Alshehri, Saad M; Suzuki, Norihiro; Yamauchi, Yusuke

    2016-04-01

    Prussian blue (PB) nanoparticles, one of many cyano-bridged coordination polymers, are successfully incorporated into chitosan (CS) polymer to prepare PB/CS mixed matrix membranes (MMMs). The PB nanoparticles are uniformly distributed in the MMMs without the collapse of the original PB structure. As-prepared PB/CS MMMs are used for ethanol dehydration at 25 °C in the pervaporation process. The effect of loading PB in CS matrix on pervaporation performance is carefully investigated. The PB/CS membrane with 30 wt% PB loading shows the best performance with a permeate flux of 614 g. m-2 . h-1 and a separation factor of 1472. The pervaporation using our PB/CS membranes exhibits outstanding performance in comparison with the previously reported CS-based membranes and MMMs. Furthermore, the addition of PB allows PB/CS MMMs to be tolerant of acidic environment. The present work demonstrates good pervaporation performance of PB/CS MMMs for the separation of an ethanol/water (90:10 in wt%) solution. Our new system provides an opportunity for dehydration of bioethanol in the future.

  19. PECM: prediction of extracellular matrix proteins using the concept of Chou's pseudo amino acid composition.

    Science.gov (United States)

    Zhang, Jian; Sun, Pingping; Zhao, Xiaowei; Ma, Zhiqiang

    2014-12-21

    The extracellular matrix proteins (ECMs) are widely found in the tissues of multicellular organisms. They consist of various secreted proteins, mainly polysaccharides and glycoproteins. The ECMs involve the exchange of materials and information between resident cells and the external environment. Accurate identification of ECMs is a significant step in understanding the evolution of cancer as well as promises wide range of potential applications in therapeutic targets or diagnostic markers. In this paper, an accurate computational method named PECM is proposed for identifying ECMs. Here, we explore various sequence-derived discriminative features including evolutionary information, predicted secondary structure, and physicochemical properties. Rather than simply combining the features which may bring information redundancy and unwanted noises, we use Fisher-Markov selector and incremental feature selection approach to search the optimal feature subsets. Then, we train our model by the technique of support vector machine (SVM). PECM achieves good prediction performance with the ACC scores about 86% and 90% on testing and independent datasets, which are competitive with the state-of-the-art ECMs prediction tools. A web-server named PECM which implements the proposed approach is freely available at http://59.73.198.144:8088/PECM/.

  20. Modal Similarity

    OpenAIRE

    Vigo , Dr. Ronaldo

    2009-01-01

    Just as Boolean rules define Boolean categories, the Boolean operators define higher-order Boolean categories referred to as modal categories. We examine the similarity order between these categories and the standard category of logical identity (i.e. the modal category defined by the biconditional or equivalence operator). Our goal is 4-fold: first, to introduce a similarity measure for determining this similarity order; second, to show that such a measure is a good predictor of the similari...

  1. Web Similarity

    OpenAIRE

    Cohen, Andrew; Vitányi, Paul

    2015-01-01

    Normalized web distance (NWD) is a similarity or normalized semantic distance based on the World Wide Web or any other large electronic database, for instance Wikipedia, and a search engine that returns reliable aggregate page counts. For sets of search terms the NWD gives a similarity on a scale from 0 (identical) to 1 (completely different). The NWD approximates the similarity according to all (upper semi)computable properties. We develop the theory and give applications. The derivation of ...

  2. Similarity Judgment of Product Structure Based on Non negative Matrix Factorization and Its Applications%基于非负矩阵分解的产品结构相似性判断及其应用

    Institute of Scientific and Technical Information of China (English)

    徐新胜; 王诚; 肖颖

    2016-01-01

    为了快速发现可重用产品结构,提出了基于非负矩阵分解的产品结构相似性判断方法。通过将产品结构邻接矩阵转化为邻接向量,构建包含全部结构信息的库矩阵;利用 Multiplicative Updates (MU)算法对库矩阵进行非负矩阵分解,实现以低维空间向量描述的产品结构;在此基础上,通过计算低维向量的欧氏距离,可以判断产品结构之间的相似性;最后通过实例对所提出原理和方法进行了验证,结果表明,该方法比目前的相似性判断方法更高效。%In order to find reusable product structure promptly,an approach of measuring the similarity among product structures was proposed based on non�negative matrix factorization.A comG prehensive matrix which containsed all structures was constructed on the basic of adj acent vectors that were transformed from the adj acent matrices of product structures.The non�negative matrix factorizaG tion for the comprehensive matrix was implemented based on Multiplicative Updates(MU)algorithm. Then all product structures might be described in low dimensional space.On the basis of these,the similarity between two product structures could be measured by calculating the Euclidean distance aG mong these low dimensional vectors.Finally,an example was presented to verify the principles and methods mentioned above.The results show that the proposed methodologies are more effective than those of the existing methods.

  3. Matrix effect on serum uric acid determination%血清尿酸测定的基质效应

    Institute of Scientific and Technical Information of China (English)

    张江涛; 王冬环; 张传宝; 曾洁; 马嵘; 赵海舰; 周伟燕; 张天娇; 闫颖; 胡翠华; 汪静

    2016-01-01

    Objective To evaluate the matrix effect of 21 samples (sera and processed materials) on 13 routine determination systems in serum uric acid determination. Methods Determinations were performed according to the health industry standard WS/T356-2011. Isotope dilution liquid chromatography tandem mass spectrometry (ID-LC/MS/MS)was used as comparison method,and 13 kinds of uric acid kits(enzymic assay) were chosen as evaluation method with HITACHI 7180 analyzer. The 21 samples included 4 calibrators,5 kinds of external quality assessment(EQA) samples,6 kinds of quality control materials,3 processed materials (1 kind of spine serum and 2 kinds of liquid solutions),1 kind of standard reference material(SRM) 909c from the National Institute of Standards and Technology (NIST)and 2 kinds of the External Quality Assessment Scheme for Reference Laboratories in Laboratory Medicine (RELA)samples from the International Federation of Clinical Chemistry and Laboratory Medicine(IFCC). A total of 40 fresh frozen sera and the 21 samples were analyzed by comparison method and evaluation method. The results obtained by the 2 methods were analyzed by linear regression analysis. Two-tailed 95% confidence intervals for Y predictive value were computed,and the matrix effect of sera and processed materials was evaluated. Results A total of 5 kinds of evaluation samples (2 EQA samples,1 SRM 909c and 2 RELA samples)from fresh or lyophilized sera showed no matrix effect in all routine methods. Two calibrators (Landau and Dirui) showed matrix effect in 1 routine method. Of 5 EQA samples,except for fresh sera used for trueness verification,other lyophilized sera showed matrix effect in most routine methods. The 4 of 6 quality control materials showed no matrix effect,and 2 quality control materials with high values showed negative matrix effect. Conclusions Fresh serum is a reliable sample and could be used in SRM and quality control material preparation and EQA. Some calibrators could

  4. Fluorescence Properties of Eu3+/Gd3+/Citric Acid Mixed Complexes Doping in Silicon Rubber Matrix

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Series of doped rare earth complexes-EuxGd(1-x)(CA)3·nH2O (CA=citric acid) were synthesized. Some characterizations were taken for these complexes. The experimental results shows that the doped rare earth complexes have the best fluorescence property when the ratio of Eu and Gd is from 0.7 to 0.3. Silicon rubber-based composites were prepared by mechanical blending the EuxGd(1-x)(CA)3·nH2O and silicon rubber. Then, the fluorescent property of the composites was studied. It is found that the fluorescence intensity of the composites increase linearly with the contents of the rare earth complexes increasing.

  5. Low pressure process for continuous fiber reinforced polyamic acid resin matrix composite laminates

    Science.gov (United States)

    Druyun, Darleen A. (Inventor); Hou, Tan-Hung (Inventor); Kidder, Paul W. (Inventor); Reddy, Rakasi M. (Inventor); Baucom, Robert M. (Inventor)

    1994-01-01

    A low pressure processor was developed for preparing a well-consolidated polyimide composite laminate. Prepreg plies were formed from unidirectional fibers and a polyamic acid resin solution. Molding stops were placed at the sides of a matched metal die mold. The prepreg plies were cut shorter than the length of the mold in the in-plane lateral direction and were stacked between the molding stops to a height which was higher than the molding stops. The plies were then compressed to the height of the stops and heated to allow the volatiles to escape and to start the imidization reaction. After removing the stops from the mold, the heat was increased and 0 - 500 psi was applied to complete the imidization reaction. The heat and pressure were further increased to form a consolidated polyimide composite laminate.

  6. Eicosapentaenoic acid inhibits TNF-α-induced matrix metalloproteinase-9 expression in human keratinocytes, HaCaT cells

    International Nuclear Information System (INIS)

    Eicosapentaenoic acid (EPA) is an omega-3 (ω-3) polyunsaturated fatty acid (PUFA), which has anti-inflammatory and anti-cancer properties. Some reports have demonstrated that EPA inhibits NF-κB activation induced by tumor necrosis factor (TNF)-α or lipopolysaccharide (LPS) in various cells. However, its detailed mode of action is unclear. In this report, we investigated whether EPA inhibits the expression of TNF-α-induced matrix metalloproteinases (MMP)-9 in human immortalized keratinocytes (HaCaT). TNF-α induced MMP-9 expression by NF-κB-dependent pathway. Pretreatment of EPA inhibited TNF-α-induced MMP-9 expression and p65 phosphorylation. However, EPA could not affect IκB-α phosphorylation, nuclear translocation of p65, and DNA binding activity of NF-κB. EPA inhibited TNF-α-induced p65 phosphorylation through p38 and Akt inhibition and this inhibition was IKKα-dependent event. Taken together, we demonstrate that EPA inhibits TNF-α-induced MMP-9 expression through inhibition of p38 and Akt activation

  7. Use of stirred tanks for studying matrix effects caused by inorganic acids, easily ionized elements and organic solvents in inductively coupled plasma atomic emission spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Paredes, Eduardo [Departamento de Quimica Analitica, Nutricion y Bromatologia, University of Alicante, 03080 Alicante (Spain); Maestre, Salvador E. [Departamento de Quimica Analitica, Nutricion y Bromatologia, University of Alicante, 03080 Alicante (Spain); Todoli, Jose L. [Departamento de Quimica Analitica, Nutricion y Bromatologia, University of Alicante, 03080 Alicante (Spain)]. E-mail: jose.todoli@ua.es

    2006-03-15

    A stirred tank was used for the first time to elucidate the mechanism responsible for inductively coupled plasma atomic emission spectroscopy (ICP-AES) matrix effects caused by inorganic, acids and easily ionized elements (EIEs), as well as organic, ethanol and acetic acid, compounds. In order to gradually increase the matrix concentration, a matrix solution was introduced inside a stirred container (tank) initially filled with an aqueous multielement standard. PolyTetraFluoroEthylene (PTFE) tubing was used to deliver the resulting solution to the liquid sample introduction system. Matrix concentration ranged from 0 to 2 mol l{sup -1} in the case of inorganic acids (i.e., nitric, sulfuric, hydrochloric and a mixture of them), from 0 to about 2500 mg l{sup -1} for EIEs (i.e., sodium, calcium and mixtures of both) and from 0% to 15%, w/w for organic compounds. Up to 40-50 different solutions were prepared and measured in a period of time shorter than 6-7 min. This investigation was carried out in terms of emission intensity and tertiary aerosols characteristics. The experimental setup used in the present work allowed to thoroughly study the effect of matrix concentration on analytical signal. Generally speaking, the experiments concerning tertiary aerosol characterization revealed that, in the case of inorganic acids and EIEs, the mechanism responsible for changes in aerosol characteristics was the droplet fission. In contrast, for organic matrices it was found that the interference was caused by a change in both aerosol transport and plasma thermal characteristics. The extent of the interferences caused by organic as well as inorganic compounds was compared for a set of 14 emission lines through a wide range of matrix concentrations. With a stirred tank, it is possible to choose an efficient internal standard for any given matrix composition. The time required to complete this procedure was shorter than 7 min.

  8. Vesiculoviral matrix (M) protein occupies nucleic acid binding site at nucleoporin pair (Rae1∙Nup98)

    Energy Technology Data Exchange (ETDEWEB)

    Quan, Beili; Seo, Hyuk-Soo; Blobel, Günter; Ren, Yi [Rockefeller

    2014-07-01

    mRNA export factor 1 (Rae1) and nucleoporin 98 (Nup98) are host cell targets for the matrix (M) protein of vesicular stomatitis virus (VSV). How Rae1 functions in mRNA export and how M protein targets both Rae1 and Nup98 are not understood at the molecular level. To obtain structural insights, we assembled a 1:1:1 complex of M•Rae1•Nup98 and established a crystal structure at 3.15-Å resolution. We found that the M protein contacts the Rae1•Nup98 heterodimer principally by two protrusions projecting from the globular domain of M like a finger and thumb. Both projections clamp to the side of the β-propeller of Rae1, with the finger also contacting Nup98. The most prominent feature of the finger is highly conserved Methionine 51 (Met51) with upstream and downstream acidic residues. The complementary surface on Rae1 displays a deep hydrophobic pocket, into which Met51 fastens like a bolt, and a groove of basic residues on either side, which bond to the acidic residues of the finger. Notably, the M protein competed for in vitro binding of various oligonucleotides to Rae1•Nup98. We localized this competing activity of M to its finger using a synthetic peptide. Collectively, our data suggest that Rae1 serves as a binding protein for the phosphate backbone of any nucleic acid and that the finger of M mimics this ligand. In the context of mRNA export, we propose that a given mRNA segment, after having been deproteinated by helicase, is transiently reproteinated by Nup98-tethered Rae1. We suggest that such repetitive cycles provide cytoplasmic stopover sites required for ratcheting mRNA across the nuclear pore.

  9. Effects of spray-drying on w/o/w multiple emulsions prepared from a stearic acid matrix

    Directory of Open Access Journals (Sweden)

    Mlalila N

    2014-12-01

    Full Text Available Nichrous Mlalila,1 Hulda Swai,2 Lonji Kalombo,2 Askwar Hilonga3 1School of Life Sciences and Bioengineering, Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania; 2Materials Science and Manufacturing, Council for Scientific and Industrial Research, Pretoria, South Africa; 3Department of Materials Science and Engineering, Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania Abstract: The goal of this study was to explore the effects of spray-drying on w/o/w double emulsions of methyltestosterone (MT loaded in a stearic acid matrix. MT-loaded nanoparticles were formulated by a water-in-oil-in-water emulsion technique using 50, 75, and 100 mg of stearic acid, 2% and 3% w/v polyvinyl alcohol, 5% w/v lactose, and 0.2% w/v chitosan. The emulsions were immediately spray-dried based on an optimized model of inlet temperature and pump rate, and characterized for optimized responses with regard to particle size, polydispersity index, and zeta potential, for both emulsion and powder samples. Dynamic light scattering analysis shown that the nanoparticles increased in size with increasing concentrations of polyvinyl alcohol and stearic acid. Scanning electron microscopy indicated that the MT-loaded nanoparticles were spherical in shape, had a smooth surface, and were in an amorphous state, which was confirmed by differential scanning calorimetry. These MT-loaded nanoparticles are a promising candidate carrier for the delivery of MT; however, further studies are needed in order to establish the stability of the system and the cargo release profile under normal conditions of use. Keywords: double emulsions, nanoparticles, pump rate, spray-drying, testosterone

  10. Porous poly(DL-lactic acid) matrix film with antimicrobial activities for wound dressing application.

    Science.gov (United States)

    Chitrattha, Sasiprapa; Phaechamud, Thawatchai

    2016-01-01

    Poly(lactic acid) (PLA) is polymeric biomaterial that has been used for wound dressing due to its biodegradability and biocompatibility. However, PLA has some limitations including poor toughness, low degradation rate and high hydrophobicity. The aim of this study is to develop an antibiotic drug-loaded PLA porous film as wound dressing with antibacterial activity. PLA porous film was fabricated by temperature change technique using solvent casting method. Polyethylene glycol (PEG) 400 was added for improving the pore interconnectivity of film. Gentamicin sulfate (GS) or metronidazole (MZ) was incorporated into PLA porous films. PLA containing PEG 400 exhibited the more amorphous form than plain PLA film and contained 55.31 ± 2.85% porosity and 20 μm of the pore size which significantly improved the water vapor transmission rate, oxygen transmission rate, degradation rate and percentage of drug release, respectively. Drug-loaded porous films efficiently inhibited the bacteria growth. GS-loaded film inhibited Staphylococcus aureus, Proteus mirabilis, Pseudomonas aeruginosa, whereas MZ-loaded film inhibited Bacteroides fragilis and the sustainable antibacterial activity was attained for 7 days.

  11. The Effects of Omega-3 Fatty Acids on Matrix Metalloproteinase-9 Production and Cell Migration in Human Immune Cells: Implications for Multiple Sclerosis

    OpenAIRE

    Lynne Shinto; Gail Marracci; Lauren Bumgarner; Vijayshree Yadav

    2011-01-01

    In multiple sclerosis (MS), compromised blood-brain barrier (BBB) integrity contributes to inflammatory T cell migration into the central nervous system. Matrix metalloproteinase-9 (MMP-9) is associated with BBB disruption and subsequent T cell migration into the CNS. The aim of this paper was to evaluate the effects of omega-3 fatty acids on MMP-9 levels and T cell migration. Peripheral blood mononuclear cells (PBMC) from healthy controls were pretreated with two types of omega-3 fatty acids...

  12. The Expression of Bone Morphogenetic Protein 2 and Matrix Metalloproteinase 2 through Retinoic Acid Receptor Beta Induced by All-Trans Retinoic Acid in Cultured ARPE-19 Cells.

    Directory of Open Access Journals (Sweden)

    Zhenya Gao

    Full Text Available All-trans retinoic acid (ATRA plays an important role in ocular development. Previous studies found that retinoic acid could influence the metabolism of scleral remodeling by promoting retinal pigment epithelium (RPE cells to secrete secondary signaling factors. The purpose of this study was to investigate whether retinoic acid affected secretion of bone morphogenetic protein 2 (BMP-2 and matrix metalloproteinase 2 (MMP-2 and to explore the signaling pathway of retinoic acid in cultured acute retinal pigment epithelial 19 (ARPE-19 cells.The effects of ATRA (concentrations from 10-9 to 10-5 mol/l on the expression of retinoic acid receptors (RARs in ARPE-19 cells were examined at the mRNA and protein levels using reverse transcription-polymerase chain reaction (RT-PCR and western blot assay, respectively. The effects of treating ARPE-19 cells with ATRA concentrations ranging from 10-9 to 10-5 mol/l for 24 h and 48 h or with 10-6mol/l ATRA at different times ranging from 6h to 72h were assessed using real-time quantitative PCR (qPCR and enzyme-linked immunosorbent assay (ELISA. The contribution of RARβ-induced activation of ARPE-19 cells was confirmed using LE135, an antagonist of RARβ.RARβ mRNA levels significantly increased in the ARPE-19 cells treated with ATRA for 24h and 48h. These increases in RARβ mRNA levels were dose dependent (at concentrations of 10-9 to 10-5 mol/l with a maximum effect observed at 10-6 mol/l. There were no significant changes in the mRNA levels of RARα and RARγ. Western blot assay revealed that RARβ protein levels were increased significantly in a time-dependent manner in ARPE-19 cells treated with 10-6 mol/l ATRA from 12 h to 72 h, with a marked increase observed at 24 h and 48 h. The upregulation of RARβ and the ATRA-induced secretion in ARPE-19 cells could be inhibited by the RARβ antagonist LE135.ATRA induced upregulation of RARβ in ARPE-19 cells and stimulated these cells to secrete BMP-2 and MMP-2.

  13. The Expression of Bone Morphogenetic Protein 2 and Matrix Metalloproteinase 2 through Retinoic Acid Receptor Beta Induced by All-Trans Retinoic Acid in Cultured ARPE-19 Cells

    Science.gov (United States)

    Gao, Zhenya; Huo, Lijun; Cui, Dongmei; Yang, Xiao; Zeng, Junwen

    2016-01-01

    Purpose All-trans retinoic acid (ATRA) plays an important role in ocular development. Previous studies found that retinoic acid could influence the metabolism of scleral remodeling by promoting retinal pigment epithelium (RPE) cells to secrete secondary signaling factors. The purpose of this study was to investigate whether retinoic acid affected secretion of bone morphogenetic protein 2 (BMP-2) and matrix metalloproteinase 2 (MMP-2) and to explore the signaling pathway of retinoic acid in cultured acute retinal pigment epithelial 19 (ARPE-19) cells. Methods The effects of ATRA (concentrations from 10−9 to 10−5 mol/l) on the expression of retinoic acid receptors (RARs) in ARPE-19 cells were examined at the mRNA and protein levels using reverse transcription-polymerase chain reaction (RT-PCR) and western blot assay, respectively. The effects of treating ARPE-19 cells with ATRA concentrations ranging from 10−9 to 10−5 mol/l for 24 h and 48 h or with 10-6mol/l ATRA at different times ranging from 6h to 72h were assessed using real-time quantitative PCR (qPCR) and enzyme-linked immunosorbent assay (ELISA). The contribution of RARβ-induced activation of ARPE-19 cells was confirmed using LE135, an antagonist of RARβ. Results RARβ mRNA levels significantly increased in the ARPE-19 cells treated with ATRA for 24h and 48h. These increases in RARβ mRNA levels were dose dependent (at concentrations of 10−9 to 10−5 mol/l) with a maximum effect observed at 10−6 mol/l. There were no significant changes in the mRNA levels of RARα and RARγ. Western blot assay revealed that RARβ protein levels were increased significantly in a time-dependent manner in ARPE-19 cells treated with 10−6 mol/l ATRA from 12 h to 72 h, with a marked increase observed at 24 h and 48 h. The upregulation of RARβ and the ATRA-induced secretion in ARPE-19 cells could be inhibited by the RARβ antagonist LE135. Conclusion ATRA induced upregulation of RARβ in ARPE-19 cells and stimulated

  14. The composition of acids in bitumen and in products from saponification of kerogen: Investigation of their role as connecting kerogen and mineral matrix

    Energy Technology Data Exchange (ETDEWEB)

    Razvigorova, M.; Budinova, T.; Tsyntsarski, B.; Petrova, B. [Bulgarian Academy of Sciences, Institute of Organic Chemistry, 1113 Sofia, Acad. Bonchev Str., bl. 9 (Bulgaria); Ekinci, E. [ISIK University, Kumbaba Mevkii, 34980 Istanbul (Turkey); Atakul, H. [Istanbul Technical University, Department of Chemical Engineering, Maslak, 34469 Istanbul (Turkey)

    2008-11-03

    In order to obtain more information and to understand the nature of relation between organic and mineral matter in oil shales, the compositions of soluble bitumen fractions obtained by extraction from Bulgarian oil shales before and after demineralization with 10% HCl, concentrated HF, and a HF/HCl mixture were investigated. The four extracts were quantitatively examined by IR and {sup 1}H NMR spectroscopy. The investigation of isolated acidic material of the bitumen fractions showed that the fatty acids are present in bitumen fractions as free acids, esters and salts. The amount of free acids in bitumen is very small. The dominant part of bitumen acids is associated with mineral components of the oil shales as well as part of them is included in the mineral matrix, and can be separated only after deep demineralization. The kerogen of the oil shales, obtained after separation of the bitumen fractions and mineral components, was subjected to saponification in order to determine the amount of acids, bound as esters to the kerogen matrix. The major components found were n-carboxylic, {alpha},{omega}-di-carboxylic, and aromatic acids. The connection of kerogen with mineral components is accomplished by the participation of carboxylic and complicated ester bonds. Experimental data for the composition of bitumen acids give evidence that algae and terrestrial materials are initial sources in the formation of soluble organic matter of Bulgarian oil shale. (author)

  15. Thimet oligopeptidase: similarity to 'soluble angiotensin II-binding protein' and some corrections to the published amino acid sequence of the rat testis enzyme.

    Science.gov (United States)

    McKie, N; Dando, P M; Rawlings, N D; Barrett, A J

    1993-01-01

    The deduced amino acid sequence of pig liver soluble angiotensin II-binding protein [Sugiura, Hagiwara and Hirose (1992) J. Biol. Chem. 267, 18067-18072] is similar over most of its length to that reported for rat testis thimet oligopeptidase (EC 3.4.24.15) by Pierotti, Dong, Glucksman, Orlowski and Roberts [(1990) (Biochemistry 29, 10323-10329]. We have found that homogeneous rat testis thimet oligopeptidase binds angiotensin II with the same distinctive characteristics as the pig liver protein. Analysis of the nucleotide sequences reported for the two proteins pointed to the likelihood that sequencing errors had caused two segments of the amino acid sequence of the rat protein to be translated out of frame, and re-sequencing of selected parts of the clone (kindly provided by the previous authors) confirmed this. The revised deduced amino acid sequence of rat thimet oligopeptidase contains 687 residues, representing a protein of 78,308 Da, and is more closely related to those of the pig liver protein and other known homologues of thimet oligopeptidase than that described previously. Images Figure 1 PMID:8216239

  16. Stiffness of hyaluronic acid gels containing liver extracellular matrix supports human hepatocyte function and alters cell morphology.

    Science.gov (United States)

    Deegan, Daniel B; Zimmerman, Cynthia; Skardal, Aleksander; Atala, Anthony; Shupe, Thomas D

    2015-03-01

    Tissue engineering and cell based liver therapies have utilized primary hepatocytes with limited success due to the failure of hepatocytes to maintain their phenotype in vitro. In order to overcome this challenge, hyaluronic acid (HA) cell culture substrates were formulated to closely mimic the composition and stiffness of the normal liver cellular microenvironment. The stiffness of the substrate was modulated by adjusting HA hydrogel crosslinking. Additionally, the repertoire of bioactive molecules within the HA substrate was bolstered by supplementation with normal liver extracellular matrix (ECM). Primary human hepatocyte viability and phenotype were determined over a narrow physiologically relevant range of substrate stiffnesses from 600 to 4600Pa in both the presence and absence of liver ECM. Cell attachment, viability, and organization of the actin cytoskeleton improved with increased stiffness up to 4600Pa. These differences were not evident in earlier time points or substrates containing only HA. However, gene expression for the hepatocyte markers hepatocyte nuclear factor 4 alpha (HNF4α) and albumin significantly decreased on the 4600Pa stiffness at day 7 indicating that cells may not have maintained their phenotype long-term at this stiffness. Function, as measured by albumin secretion, varied with both stiffness and time in culture and peaked at day 7 at the 1200Pa stiffness, slightly below the stiffness of normal liver ECM at 3000Pa. Overall, gel stiffness affected primary human hepatocyte cell adhesion, functional marker expression, and morphological characteristics dependent on both the presence of liver ECM in gel substrates and time in culture. PMID:26569044

  17. Stiffness of hyaluronic acid gels containing liver extracellular matrix supports human hepatocyte function and alters cell morphology.

    Science.gov (United States)

    Deegan, Daniel B; Zimmerman, Cynthia; Skardal, Aleksander; Atala, Anthony; Shupe, Thomas D

    2015-03-01

    Tissue engineering and cell based liver therapies have utilized primary hepatocytes with limited success due to the failure of hepatocytes to maintain their phenotype in vitro. In order to overcome this challenge, hyaluronic acid (HA) cell culture substrates were formulated to closely mimic the composition and stiffness of the normal liver cellular microenvironment. The stiffness of the substrate was modulated by adjusting HA hydrogel crosslinking. Additionally, the repertoire of bioactive molecules within the HA substrate was bolstered by supplementation with normal liver extracellular matrix (ECM). Primary human hepatocyte viability and phenotype were determined over a narrow physiologically relevant range of substrate stiffnesses from 600 to 4600Pa in both the presence and absence of liver ECM. Cell attachment, viability, and organization of the actin cytoskeleton improved with increased stiffness up to 4600Pa. These differences were not evident in earlier time points or substrates containing only HA. However, gene expression for the hepatocyte markers hepatocyte nuclear factor 4 alpha (HNF4α) and albumin significantly decreased on the 4600Pa stiffness at day 7 indicating that cells may not have maintained their phenotype long-term at this stiffness. Function, as measured by albumin secretion, varied with both stiffness and time in culture and peaked at day 7 at the 1200Pa stiffness, slightly below the stiffness of normal liver ECM at 3000Pa. Overall, gel stiffness affected primary human hepatocyte cell adhesion, functional marker expression, and morphological characteristics dependent on both the presence of liver ECM in gel substrates and time in culture.

  18. Influence of purified multiwalled carbon nanotubes on the mechanical and morphological behavior in poly (L-lactic acid) matrix.

    Science.gov (United States)

    Leal, C V; Martinez, D S T; Más, B A; Alves, O L; Duek, E A R

    2016-06-01

    Poly (L-latic acid) (PLLA) is a bioresorbable polymer widely used as a biomaterial, but its fragility can limit its use. An alternative is to produce polymer nanocomposites, which can enhance the mechanical properties of polymeric matrix, resulting in a material with differentiated properties. In this work, PLLA based nanocomposites containing 0.25, 0.5 and 1.0wt% of purified multiwalled carbon nanotubes (p-MWCNTs) were prepared by the solvent casting method. The morphology and mechanical properties results show an improvement in strain at break for 0.25 and 0.5wt% p-MWCNTs and an increase in stiffness and elastic modulus for all compositions. Nanocomposites presented a p-MWCNTs agglomeration; however, there was a good stress transfer between PLLA and p-MWCNTs, which was confirmed by the increase in the hardness and elastic modulus. Atomic force microscopy analysis indicated an increase in roughness after nanotube addition. The in vitro biological study showed that PLLA/p-MWCNTs nanocomposites are cytocompatible with osteoblasts cells. The capacity of PLLA nanocomposites to stimulate osteogenesis was investigated by alkaline phosphatase (ALP) activity assay. Higher ALP activity was found on osteoblasts cultured on nanocomposites with 0.25 and 0.5wt% p-MWCNT compared to neat PLLA, confirming that PLLA cytocompatibility was improved on these compositions. Finally, our results showed that by a simple and inexpensive solvent casting method, it is possible to manufacture biofunctional nanocomposites devices with potential for orthopedic applications. PMID:27038896

  19. Matrix Thermalization

    CERN Document Server

    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.

  20. Brain docosahexaenoic acid (DHA levels of young rats are related to alpha-linolenic acid (ALA levels and fat matrix of the diet: impact of dairy fat*

    Directory of Open Access Journals (Sweden)

    Delplanque Bernadette

    2011-11-01

    Full Text Available Dososahexaenoate (DHA is highly concentrated in mammalian nervous and visual systems and its deficiency during gestation, lactation and early life, could have dramatic impacts on brain functions and mental health. Achieving an appropriate DHA status in the neonatal brain is an important goal of neonatal nutrition. We evaluated how a-linolenic acid (ALA provided by different dietary fat matrices improved DHA content in the brains of both young male and female rats. Young rats born from dams fed during gestation and lactation with a low ALA diet (0.4% of fatty acids were subjected for 6 weeks after weaning to an anhydrous dairy fat blend-based diet that provided 1.5% ALA or to a palm oil blend-based diet that provided the same ALA level: either 1.5% ALA or 1.5% ALA and 0.12% DHA with 0.4% arachidonic acid (ARA. With each diet the n-6/ n-3 ratio was similar (10 to follow the values generally recommended for infant formula. Fatty acids analysis in whole brain showed that 1.5% ALA dairy fat blend was superior to both 1.5% ALA palm-oil blends, supplemented or not with dietary DHA, for increasing brain DHA. Females compared to males had significantly higher brain DHA with the 1.5% ALA palm-blend diet, but the dietary supplementation with DHA smoothed the differences by a specific increase of males DHA brain. In conclusion, dairy fat blend enriched with ALA appear to be an interesting strategy for achieving optimal DHA levels in the brain of post-weaning rats. Inclusion of dairy fat in infant formulas should be reconsidered.

  1. Reduction of Inflammatory Responses and Enhancement of Extracellular Matrix Formation by Vanillin-Incorporated Poly(Lactic-co-Glycolic Acid) Scaffolds

    OpenAIRE

    Lee, Yujung; Kwon, JeongIl; Khang, Gilson; Lee, Dongwon

    2012-01-01

    Vanillin is one of the major components of vanilla, a commonly used flavoring agent and preservative and is known to exert potent antioxidant and anti-inflammatory activities. In this work, vanillin-incorporated poly(lactic-co-glycolic acid) (PLGA) films and scaffolds were fabricated to evaluate the effects of vanillin on the inflammatory responses and extracellular matrix (ECM) formation in vitro and in vivo. The incorporation of vanillin to PLGA films induced hydrophilic nature, resulting i...

  2. AN AMPEROMETRIC BIOSENSOR BASED ON COVALENT IMMOBILIZATION OF ASCORBATE OXIDASE ON BIOCOMPATIABLE AND LOW-TOXIC POLY(THIOPHENE-3-ACETIC ACID) MATRIX

    Institute of Scientific and Technical Information of China (English)

    Dong Li; Yang-ping Wen; Jing-kun Xu; Hao-hua He; Ming Liu

    2012-01-01

    The biocompatiable and low-toxic poly(thiophene-3-acetic acid) (PTAA) matrix was successfully electrosynthesized in ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BmimPF6) in comparison with the electrosynthesis of PTAA matrix in acetonitrile (ACN).Ascorbate oxidase (AO) was used as a model for the development and application of biosensor.Vitamin C (VC) biosensors were facilely fabricated by the covalent immobilization of AO molecules on PTAA matrices electrosynthesized in ACN containing tetrabutylammonium tetrafluoroborate and BmimPF6,respectively.Electrochemical impedance spectroscopy,scanning electron microscopy and FTIR spectroscopy indicated that AO molecules were covalently immobilized on PTAA matrices.Parameters of the as-obtained biosensors such as working potential,pH and temperature have been optimized.The amperometric biosensor based on PTAA matrix electrosynthesized in BmimPF6 exhibited wider linear range,lower detection limit,higher sensitivity and bioaffinity,and better operational and storage stability than that electrosynthesized in ACN under optimal conditions.The as-obtained biosensor based on PTAA matrix electrosynthesized in BmimPF6 was employed for the detection of VC content in commercial juices,and the result was close to the data given by manufacturers.Excellent results indicate that the PTAA matrix electrosynthesized in ionic liquid is a promising platform for the covalent immobilization of biologically-active species and the development of biosensors.

  3. Determination of the fatty acid composition of saponified vegetable oils using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

    Science.gov (United States)

    Ayorinde, F O; Garvin, K; Saeed, K

    2000-01-01

    A method using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) for the determination of the fatty acid composition of vegetable oils is described and illustrated with the analysis of palm kernel oil, palm oil, olive oil, canola oil, soybean oil, vernonia oil, and castor oil. Solutions of the saponified oils, mixed with the matrix, meso-tetrakis(pentafluorophenyl)porphyrin, provided reproducible MALDI-TOF spectra in which the ions were dominated by sodiated sodium carboxylates [RCOONa + Na]+. Thus, palm kernel oil was found to contain capric acid, lauric acid, myristic acid, palmitic acid, oleic acid, and stearic acid. Palm oil had a fatty acid profile including palmitic, linoleic, oleic, and stearic. The relative percentages of the fatty acids in olive oil were palmitoleic (1.2 +/- 0.5), palmitic (10.9 +/- 0.8), linoleic (0.6 +/- 0.1), linoleic (16.5 +/- 0.8), and oleic (70.5 +/- 1.2). For soybean oil, the relative percentages were: palmitoleic (0.4 +/- 0.4), palmitic (6.0 +/- 1.3), linolenic (14.5 +/- 1.8), linoleic (50.1 +/- 4.0), oleic (26.1 +/- 1.2), and stearic (2.2 +/- 0.7). This method was also applied to the analysis of two commercial soap formulations. The first soap gave a fatty acid profile that included: lauric (19.4% +/- 0.8), myristic (9.6% +/- 0.5), palmitoleic (1.9% +/- 0.3), palmitic (16.3% +/- 0.9), linoleic (5.6% +/- 0.4), oleic (37.1% +/- 0.8), and stearic (10.1% +/- 0.7) and that of the second soap was: lauric (9.3% +/- 0.3), myristic (3.8% +/- 0.5), palmitoleic (3.1% +/- 0.8), palmitic (19.4% +/- 0.8), linoleic (4.9% +/- 0.7), oleic (49.5% +/- 1.1), and stearic (10.0% +/- 0.9). The MALDI-TOFMS method described in this communication is simpler and less time-consuming than the established transesterification method that is coupled with analysis by gas chromatography/mass spectrometry (GC/MS). The new method could be used routinely to determine the qualitative fatty acid composition of vegetable oils

  4. Comparative researches on two direct transmethylation without prior extraction methods for fatty acids analysis in vegetal matrix with low fat content

    Directory of Open Access Journals (Sweden)

    Harmanescu Monica

    2012-01-01

    Full Text Available Abstract Background The aim of our work was to compare two methods, both based on direct transmethylation with different reagents, BF3/MeOH (boron trifluoride in methanol or HCl/MeOH (hydrochloride acid in methanol, in acid catalysis, without prior extraction, to find the fast, non-expensive but enough precise method for 9 principal fatty acids (lauric, myristic, palmitic, stearic, oleic, linoleic, linolenic, arahidic and behenic acids analysis in vegetal matrix with low fat content (forage from grassland, for nutrition and agrochemical studies. Results Comparatively, between the average values obtained for all analysed fatty acids by the two methods based on direct transmethylation without prior extraction no significantly difference was identified (p > 0.05. The results of fatty acids for the same forage sample were more closely to their average value, being more homogenous for BF3/MeOH than HCl/MeOH, because of the better accuracy and repeatability of this method. Method that uses BF3/MeOH reagent produces small amounts of interfering compounds than the method using HCl/MeOH reagent, results reflected by the better statistical parameters. Conclusion The fast and non-expensive BF3/methanol method was applied with good accuracy and sensitivity for the determination of free or combined fatty acids (saturated and unsaturated in forage matrix with low fat content from grassland. Also, the final extract obtained by this method, poorer in interfering compounds, is safer to protect the injector and column from contamination with heavy or non-volatile compounds formed by transmethylation reactions.

  5. Thermal conductivity and acid dissolution behavior of MgO-ZrO 2 ceramics for use in LWR inert matrix fuel

    Science.gov (United States)

    Medvedev, P. G.; Lambregts, M. J.; Meyer, M. K.

    2006-02-01

    Dual-phase MgO-ZrO 2 ceramics are proposed for use in inert matrix fuel for disposition of plutonium and minor actinides in existing light water reactors. The concept for use of this composite material was developed with the intent to capitalize on the known advantages of the composite's constituents: high thermal conductivity of MgO, and stability of ZrO 2 in LWR coolant. The study presented in this paper addressed the thermal conductivity and nitric acid solubility of MgO-ZrO 2 ceramics. Thermal analysis, based on experimental and analytical techniques, established that the product of all investigated compositions has the thermal conductivity superior to that of UO 2. Nitric acid dissolution experiments showed that only the free MgO phase dissolves in the nitric acid, leaving behind a porous pellet consisting of a ZrO 2-based solid solution.

  6. Thermoreversible copolymer gels for extracellular matrix.

    Science.gov (United States)

    Vernon, B; Kim, S W; Bae, Y H

    2000-07-01

    To improve the properties of a reversible synthetic extracellular matrix based on a thermally reversible polymer, copolymers of N-isopropylacrylamide and acrylic acid were prepared in benzene with varying contents of acrylic acid (0 to 3%) and the thermal properties were evaluated. The poly(N-isopropylacrylamide) and copolymers made with acrylic acid had molecular weights from 0.8 to 1.7 x10(6) D. Differential scanning calorimetry (DSC) showed the high-molecular-weight acrylic acid copolymers had similar onset temperatures to the homopolymers, but the peak width was considerably increased with increasing acrylic acid content. DSC and cloud point measurements showed that polymers with 0 to 3% acrylic acid exhibit a lower critical solution temperature (LCST) transition between 30 degrees and 37 degrees C. In swelling studies, the homopolymer showed significant syneresis at temperatures above 31 degrees C. Copolymers with 1 and 1.5% showed syneresis beginning at 32 degrees and 37 degrees C, respectively. At 37 degrees C the copolymers with 1.5-3% acrylic acid showed little or no syneresis. Due to the high water content and a transition near physiologic conditions (below 37 degrees C), the polymers with 1.5-2.0% acrylic acid exhibited properties that would be useful in the development of a refillable synthetic extracellular matrix. Such a matrix could be applied to several cell types, including islets of Langerhans, for a biohybrid artificial pancreas.

  7. Determination of Iron in Layered Crystal Sodium Disilicate and Sodium Silicate by Flame Atomic Absorption Spectrometry with Boric Acid as a Matrix Modifier

    Institute of Scientific and Technical Information of China (English)

    Zhi Hua WANG; Min CAI; Shu Jun WANG

    2006-01-01

    The effects of matrix silicate and experimental conditions on the determination of iron in flame atomic absorption spectrometry (FAAS) were investigated. It was found that boric acid as a matrix modifier obviously eliminated silicate interference. Under the optimum operating conditions, the determination results of iron in layered crystal sodium disilicate and sodium silicate samples by FAAS were satisfactory. The linear range of calibration curve is 0-10.5 μg.mL-1, the relative standard deviation of method is 1.2%-2.2%, the recovery of added iron is 96.0%-101%, the of iron of the standard curve method, standard addition calibration and colorimetry method was the same, but the first has the merits of rapid sample preparation, reduced contamination risks and fast analysis.

  8. Ammonia-treated N-(1-naphthyl) ethylenediamine dihydrochloride as a novel matrix for rapid quantitative and qualitative determination of serum free fatty acids by matrix-assisted laser desorption/ionization-Fourier transform ion cyclotron resonance mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yaping [Department of Biophysics and Structural Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, 5 Dongdan San Tiao, Beijing 100005 (China); Wang, Yanmin [Department of Clinical Laboratory, Heze Municipal Hospital, Shandong (China); Guo, Shuai; Guo, Yumei; Liu, Hui [Department of Biophysics and Structural Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, 5 Dongdan San Tiao, Beijing 100005 (China); Li, Zhili, E-mail: lizhili@ibms.pumc.edu.cn [Department of Biophysics and Structural Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, 5 Dongdan San Tiao, Beijing 100005 (China)

    2013-09-10

    Graphical abstract: -- Highlights: •A novel MALDI matrix for the detection of serum free fatty acids is ammonia-treated N-(1-naphthyl) ethylenediamine dihydrochloride. •Multiple point internal standard calibration curves were constructed for nine FFAs, respectively, with excellent correlation coefficients between 0.991 and 0.999. •The MALDI-MS approach was used to rapidly differentiate the patients with and without hyperglycemia and healthy controls. -- Abstract: The blood free fatty acids (FFAs), which provide energy to the cell and act as substrates in the synthesis of fats, lipoproteins, liposaccharides, and eicosanoids, involve in a number of important physiological processes. In the present study, matrix-assisted laser desorption/ionization-Fourier transform ion cyclotron resonance mass spectrometry (MALDI-FTICR MS) with ammonia-treated N-(1-naphthyl) ethylenediamine dihydrochloride (ATNEDC) as a novel MALDI matrix in a negative ion mode was employed to directly quantify serum FFAs. Multiple point internal standard calibration curves between the concentration ratios of individual fatty acids to internal standard (IS, C{sub 17:0}) versus their corresponding intensity ratios were constructed for C{sub 14:0}, C{sub 16:1}, C{sub 16:0}, C{sub 18:0}, C{sub 18:1}, C{sub 18:2}, C{sub 18:3}, C{sub 20:4}, and C{sub 22:6}, respectively, in their mixture, with correlation coefficients between 0.991 and 0.999 and limits of detection (LODs) between 0.2 and 5.4 μM, along with the linear dynamic range of more than two orders of magnitude. The results indicate that the multiple point internal standard calibration could reduce the impact of ion suppression and improve quantification accuracy in the MALDI mode. The quantitative results of nine FFAs from 339 serum samples, including 161 healthy controls, 118 patients with hyperglycemia and 60 patients without hyperglycemia show that FFAs levels in hyperglycemic patient sera are significantly higher than those in healthy

  9. Simultaneous determination of bromate, chlorite and haloacetic acids by two-dimensional matrix elimination ion chromatography with coupled conventional and capillary columns.

    Science.gov (United States)

    Teh, Hui Boon; Li, Sam Fong Yau

    2015-02-27

    A new, highly sensitive and reliable two-dimensional matrix elimination ion chromatography (IC) method was developed for simultaneous detection of bromate, chlorite and five haloacetic acids. This method combined the conventional IC in first dimension with capillary IC in the second dimension coupled with suppressed conductivity detection. The first dimension utilizes a high capacity column to partially resolve matrix from target analytes. By optimizing the cut window, the target analytes were selectively cut and trapped in a trap column through the use of a six-port valve, while the separated matrix were diverted to waste. The trapped target analytes were delivered on to the capillary column for further separation and detection. Temperature programming was used to improve selectivity in second dimension column to obtain complete resolution of the target analytes. Compared to the performance of one-dimensional IC, the two-dimensional approach resulted in a significant increase in sensitivity for all target analytes with limit of detection ranging from 0.30 to 0.64μg/L and provided more reliable analysis due to second column confirmation. Good linearity was obtained for all the target analytes with correlation coefficients >0.998. The proposed method was successfully applied to the determination of oxyhalides and haloacetic acids in various matrices with recoveries ranging from 90 to 116% and RSD less than 6.1%. The method allows direct injection of samples and the use of columns with different selectivity, thus significantly reduces the level of false positive results. The method is fully automated and simple, making it practical for routine monitoring of water quality. The satisfactory results also demonstrated that the two-dimensional matrix elimination method coupled with capillary IC is a promising approach for detection of trace substances in complex matrices.

  10. Influence of the composition of hydroxypropyl cellulose/maleic acid-alt-styrene copolymer blends on their properties as matrix for drug release

    Directory of Open Access Journals (Sweden)

    2009-05-01

    Full Text Available Poly(carboxylic acid-polysaccharide compositions have been found suitable for obtaining drug formulations with controlled release, most formulations being therapeutically efficacious, stable, and non-irritant. The influence of the characteristics of the aqueous solutions from which the polymer matrix is prepared (i.e. the total concentration of polymer in solutions and the mixing ratio between the partners, hydroxypropyl cellulose, HPC and maleic acid-alternating-styrene copolymer, MAc-alt-S on the kinetics of some drugs release in acidic environment (pH = 2 has been followed by ‘in vitro’ dissolution tests. It has been established that the kinetics of procaine hydrochloride release from HPC/MAc-alt-S matrix depends on its composition; the diffusion exponent, n is close to 0.5 for matrices where one of the components is in large excess and n~0.02 for middle composition range. The lower value of diffusion exponent for middle composition range could be caused by the so called ‘burst effect’, therefore the kinetic evaluation is difficult.

  11. On-Tissue Derivatization via Electrospray Deposition for Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging of Endogenous Fatty Acids in Rat Brain Tissues.

    Science.gov (United States)

    Wu, Qian; Comi, Troy J; Li, Bin; Rubakhin, Stanislav S; Sweedler, Jonathan V

    2016-06-01

    Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) is used for the multiplex detection and characterization of diverse analytes over a wide mass range directly from tissues. However, analyte coverage with MALDI MSI is typically limited to the more abundant compounds, which have m/z values that are distinct from MALDI matrix-related ions. On-tissue analyte derivatization addresses these issues by selectively tagging functional groups specific to a class of analytes, while simultaneously changing their molecular masses and improving their desorption and ionization efficiency. We evaluated electrospray deposition of liquid-phase derivatization agents as a means of on-tissue analyte derivatization using 2-picolylamine; we were able to detect a range of endogenous fatty acids with MALDI MSI. When compared with airbrush application, electrospray led to a 3-fold improvement in detection limits and decreased analyte delocalization. Six fatty acids were detected and visualized from rat cerebrum tissue using a MALDI MSI instrument operating in positive mode. MALDI MSI of the hippocampal area allowed targeted fatty acid analysis of the dentate gyrus granule cell layer and the CA1 pyramidal layer with a 20-μm pixel width, without degrading the localization of other lipids during liquid-phase analyte derivatization.

  12. On-Tissue Derivatization via Electrospray Deposition for Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging of Endogenous Fatty Acids in Rat Brain Tissues.

    Science.gov (United States)

    Wu, Qian; Comi, Troy J; Li, Bin; Rubakhin, Stanislav S; Sweedler, Jonathan V

    2016-06-01

    Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) is used for the multiplex detection and characterization of diverse analytes over a wide mass range directly from tissues. However, analyte coverage with MALDI MSI is typically limited to the more abundant compounds, which have m/z values that are distinct from MALDI matrix-related ions. On-tissue analyte derivatization addresses these issues by selectively tagging functional groups specific to a class of analytes, while simultaneously changing their molecular masses and improving their desorption and ionization efficiency. We evaluated electrospray deposition of liquid-phase derivatization agents as a means of on-tissue analyte derivatization using 2-picolylamine; we were able to detect a range of endogenous fatty acids with MALDI MSI. When compared with airbrush application, electrospray led to a 3-fold improvement in detection limits and decreased analyte delocalization. Six fatty acids were detected and visualized from rat cerebrum tissue using a MALDI MSI instrument operating in positive mode. MALDI MSI of the hippocampal area allowed targeted fatty acid analysis of the dentate gyrus granule cell layer and the CA1 pyramidal layer with a 20-μm pixel width, without degrading the localization of other lipids during liquid-phase analyte derivatization. PMID:27181709

  13. All-trans retinoic acid regulates the expression of the extracellular matrix protein fibulin-1 in the guinea pig sclera and human scleral fibroblasts

    OpenAIRE

    Li, Chuanxu; McFadden, Sally A.; Morgan, Ian; Cui, Dongmei; Hu, Jianmin; Wan, Wenjuan; Zeng, Junwen

    2010-01-01

    Purpose Fibulin-1 (FBLN1) mRNA is expressed in human sclera and is an important adhesion modulatory protein that can affect cell–matrix interactions and tissue remodeling. Scleral remodeling is influenced by all-trans retinoic acid (RA). Our purpose was to confirm the presence of fibulin-1 protein in guinea pig sclera and investigate the effect of RA on the expression of fibulin-1 in guinea pig sclera in vivo and in cultured human scleral fibroblasts (HSFs). Methods Confocal fluorescence micr...

  14. The Effects of Omega-3 Fatty Acids on Matrix Metalloproteinase-9 Production and Cell Migration in Human Immune Cells: Implications for Multiple Sclerosis

    Directory of Open Access Journals (Sweden)

    Lynne Shinto

    2011-01-01

    Full Text Available In multiple sclerosis (MS, compromised blood-brain barrier (BBB integrity contributes to inflammatory T cell migration into the central nervous system. Matrix metalloproteinase-9 (MMP-9 is associated with BBB disruption and subsequent T cell migration into the CNS. The aim of this paper was to evaluate the effects of omega-3 fatty acids on MMP-9 levels and T cell migration. Peripheral blood mononuclear cells (PBMC from healthy controls were pretreated with two types of omega-3 fatty acids, eicosapentaenoic acid (EPA, and docosahexaenoic acid (DHA. Cell supernatants were used to determine MMP-9 protein and activity levels. Jurkat cells were pretreated with EPA and DHA and were added to fibronectin-coated transwells to measure T cell migration. EPA and DHA significantly decreased MMP-9 protein levels, MMP-9 activity, and significantly inhibited human T cell migration. The data suggest that omega-3 fatty acids may benefit patients with multiple sclerosis by modulating immune cell production of MMP-9.

  15. A Similarity Search Using Molecular Topological Graphs

    OpenAIRE

    2009-01-01

    A molecular similarity measure has been developed using molecular topological graphs and atomic partial charges. Two kinds of topological graphs were used. One is the ordinary adjacency matrix and the other is a matrix which represents the minimum path length between two atoms of the molecule. The ordinary adjacency matrix is suitable to compare the local structures of molecules such as functional groups, and the other matrix is suitable to compare the global structures of molecules. The comb...

  16. GLYCOLIC-NITRIC ACID FLOWSHEET DEMONSTRATION OF THE DWPF CHEMICAL PROCESSING CELL WITH MATRIX SIMULANTS AND SUPERNATE

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, D.; Stone, M.; Newell, J.; Best, D.

    2012-05-07

    Savannah River Remediation (SRR) is evaluating changes to its current DWPF flowsheet to improve processing cycle times. This will enable the facility to support higher canister production while maximizing waste loading. Higher throughput is needed in the CPC since the installation of the bubblers into the melter has increased melt rate. Due to the significant maintenance required for the DWPF gas chromatographs (GC) and the potential for production of flammable quantities of hydrogen, reducing or eliminating the amount of formic acid used in the CPC is being developed. Earlier work at Savannah River National Laboratory has shown that replacing formic acid with an 80:20 molar blend of glycolic and formic acids has the potential to remove mercury in the SRAT without any significant catalytic hydrogen generation. This report summarizes the research completed to determine the feasibility of processing without formic acid. In earlier development of the glycolic-formic acid flowsheet, one run (GF8) was completed without formic acid. It is of particular interest that mercury was successfully removed in GF8, no formic acid at 125% stoichiometry. Glycolic acid did not show the ability to reduce mercury to elemental mercury in initial screening studies, which is why previous testing focused on using the formic/glycolic blend. The objective of the testing detailed in this document is to determine the viability of the nitric-glycolic acid flowsheet in processing sludge over a wide compositional range as requested by DWPF. This work was performed under the guidance of Task Technical and Quality Assurance Plan (TT and QAP). The details regarding the simulant preparation and analysis have been documented previously.

  17. A Similarity Search Using Molecular Topological Graphs

    Directory of Open Access Journals (Sweden)

    Yoshifumi Fukunishi

    2009-01-01

    Full Text Available A molecular similarity measure has been developed using molecular topological graphs and atomic partial charges. Two kinds of topological graphs were used. One is the ordinary adjacency matrix and the other is a matrix which represents the minimum path length between two atoms of the molecule. The ordinary adjacency matrix is suitable to compare the local structures of molecules such as functional groups, and the other matrix is suitable to compare the global structures of molecules. The combination of these two matrices gave a similarity measure. This method was applied to in silico drug screening, and the results showed that it was effective as a similarity measure.

  18. Effect of pioglitazone, quercetin and hydroxy citric acid on extracellular matrix components in experimentally induced non-alcoholic steatohepatitis

    Directory of Open Access Journals (Sweden)

    Surapaneni Krishna Mohan

    2015-08-01

    Results:The experimental NASH rats treated with pioglitazone showed significant decrease in the levels of hyaluronic acid and significant increase in adiponectin levels when compared to experimentally induced NASH group, but did not show any effect on the levels of leptin. Contrary to these two drugs, viz. pioglitazone and hydroxy citric acid, the group treated with quercetin showedsignificant decrease in the levels of hyaluronic acid and leptin and significant decrease in adiponectin levels compared with that of experimentally induced NASH NASH group, offering maximum protection against NASH. Conclusion: Considering our findings, it could be concluded that quercetin may offer maximum protection against NASH by significantly increasing the levels of adiponectin, when compared to pioglitazone and hydroxy citric acid.

  19. Assessment of antimicrobial resistance transfer between lactic acid bacteria and potential foodborne pathogens using in vitro methods and mating in a food matrix.

    Science.gov (United States)

    Toomey, Niamh; Monaghan, Aine; Fanning, Séamus; Bolton, Declan J

    2009-10-01

    The transferability of antimicrobial resistance from lactic acid bacteria (LAB) to potential pathogenic strains was studied using in vitro methods and mating in a food matrix. Five LAB donors containing either erythromycin or tetracycline resistance markers on transferable elements were conjugally mated with LAB (Enterococcus faecalis, Lactococcus lactis) and pathogenic strains (Listeria spp., Salmonella ssp., Staphylococcus aureus, and Escherichia coli). In vitro transfer experiments were carried out with the donors and recipients using both the filter and plate mating methods. The food matrix consisted of fermented whole milk (fermented with the LAB donors) with the pathogenic recipients added as contaminants during the production process. All transconjugants were confirmed by phenotypic and molecular methods. Erythromycin resistance transfer from LAB strains to Listeria spp. was observed using both in vitro mating methods at high transfer frequencies of up to 5.1 x 10(-4) transconjugants per recipient. Also, high frequency transfer (ranging from 2.7 x 10(-8) up to 1.1 x 10(-3) transconjugants per recipient) of both erythromycin and tetracycline-resistance was observed between LAB species using in vitro methods. No resistance transfer was observed to Salmonella spp., Staphylococcus aureus, and E. coli. The only conjugal transfer observed in the fermented milk matrix was for tetracycline resistance between two LAB strains (at a transfer frequency of 2.6 x 10(-7) transconjugants per recipients). This study demonstrates the transfer of antimicrobial resistance from LAB to Listeria spp. using in vitro methods and also the transfer of resistance between LAB species in a food matrix. It highlights the involvement of LAB as a potential source of resistance determinants that may be disseminated between LAB and pathogenic strains including Listeria spp. Furthermore, it indicates that food matrices such as fermented milks may provide a suitable environment to support gene

  20. Properties and mechanisms of drug release from matrix tablets containing poly(ethylene oxide) and poly(acrylic acid) as release retardants.

    Science.gov (United States)

    Zhang, Feng; Meng, Fan; Lubach, Joseph; Koleng, Joseph; Watson, N A

    2016-08-01

    The interactions between poly(ethylene oxide) (PEO) and poly(acrylic acid) (PAA) in aqueous medium at pH 6.8 were investigated in the current study. We have also studied the effect of interpolymer interactions and various formulation variables, including the molecular weight of PEO, the ratio between PEO and PAA, the crystallinity of PEO, and the presence of an acidifying agent, on the release of theophylline from matrix tablets containing both PEO and PAA as release retardants. At pH 6.8, the synergy in solution viscosity between PEO and PAA as the result of ion-dipole interaction was observed in this study. The release of theophylline from the matrix tablets containing physical mixtures of PEO and PAA was found to be a function of dissolution medium pH because of the pH-dependent interactions between these two polymers. Because of the formation of water insoluble interpolymer complex between PEO and PAA in aqueous medium at pH below 4.0, the release of theophylline was independent of PEO molecular weight and was controlled by Fickian diffusion mechanism in 0.01N hydrochloric acid solution. In comparison, the drug release was a function of PEO molecular weight and followed the anomalous transport mechanism in phosphate buffer pH 6.8. The presence of PAA exerted opposite effects on the release of theophylline in phosphate buffer pH 6.8. In one aspect, theophylline release was accelerated because the erosion of PAA was much faster than that of PEO at pH6.8. On the opposite aspect, theophylline release was slowed down because of the formation of insoluble complex inside the gel layer as the result of the acidic microenvironment induced by PAA, and the increase in the viscosity of the gel layer as the result of the synergy between PEO and PAA. These two opposite effects offset each other. As a result, the release of theophylline remained statistically the same even when 75% PEO in the formulation was replaced with PAA. In phosphate buffer pH 6.8, the release of

  1. Community Detection by Neighborhood Similarity

    Institute of Scientific and Technical Information of China (English)

    LIU Xu; XIE Zheng; YI Dong-Yun

    2012-01-01

    Detection of the community structure in a network is important for understanding the structure and dynamics of the network.By exploring the neighborhood of vertices,a local similarity metric is proposed,which can be quickly computed.The resulting similarity matrix retains the same support as the adjacency matrix.Based on local similarity,an agglomerative hierarchical clustering algorithm is proposed for community detection.The algorithm is implemented by an efficient max-heap data structure and runs in nearly linear time,thus is capable of dealing with large sparse networks with tens of thousands of nodes.Experiments on synthesized and real-world networks demonstrate that our method is efficient to detect community structures,and the proposed metric is the most suitable one among all the tested similarity indices.%Detection of the community structure in a network is important for understanding the structure and dynamics of the network. By exploring the neighborhood of vertices, a local similarity metric is proposed, which can be quickly computed. The resulting similarity matrix retains the same support as the adjacency matrix. Based on local similarity, an agglomerative hierarchical clustering algorithm is proposed for community detection. The algorithm is implemented by an efficient max-heap data structure and runs in nearly linear time, thus is capable of dealing with large sparse networks with tens of thousands of nodes. Experiments on synthesized and real-world networks demonstrate that our method is efficient to detect community structures, and the proposed metric is the most suitable one among all the tested similarity indices.

  2. Long- and Medium-Chain Fatty Acids Induce Insulin Resistance to a Similar Extent in Humans Despite Marked Differences in Muscle Fat Accumulation

    NARCIS (Netherlands)

    Hoeks, J.; Mensink, M.R.; Hesselink, M.K.C.; Ekroos, K.; Schrauwen, P.

    2012-01-01

    Context: Animal studies revealed that medium-chain fatty acids (MCFA), due to their metabolic characteristics, are not stored in skeletal muscle and may therefore not give rise to potentially hazardous lipid species impeding insulin signaling. Objective: We here hypothesized that infusion of medium-

  3. Unraveling the similarity of the photoabsorption of deprotonated p-coumaric acid in the gas phase and within the photoactive yellow protein

    DEFF Research Database (Denmark)

    Rinza, Tomás Rocha; Sneskov, Kristian; Christiansen, Ove;

    2011-01-01

    Using advanced QM/MM methods, the surprisingly negligible shift of the lowest-lying bright electronic excitation of the deprotonated p-coumaric acid (pCA−) within the photoactive yellow protein (PYP) is shown to stem from a subtle balance between hypsochromic and bathochromic effects. More...

  4. Unifying bacteria from decaying wood with various ubiquitous Gibbsiella species as G. acetica sp. nov. based on nucleotide sequence similarities and their acetic acid secretion.

    Science.gov (United States)

    Geider, Klaus; Gernold, Marina; Jock, Susanne; Wensing, Annette; Völksch, Beate; Gross, Jürgen; Spiteller, Dieter

    2015-12-01

    Bacteria were isolated from necrotic apple and pear tree tissue and from dead wood in Germany and Austria as well as from pear tree exudate in China. They were selected for growth at 37 °C, screened for levan production and then characterized as Gram-negative, facultatively anaerobic rods. Nucleotide sequences from 16S rRNA genes, the housekeeping genes dnaJ, gyrB, recA and rpoB alignments, BLAST searches and phenotypic data confirmed by MALDI-TOF analysis showed that these bacteria belong to the genus Gibbsiella and resembled strains isolated from diseased oaks in Britain and Spain. Gibbsiella-specific PCR primers were designed from the proline isomerase and the levansucrase genes. Acid secretion was investigated by screening for halo formation on calcium carbonate agar and the compound identified by NMR as acetic acid. Its production by Gibbsiella spp. strains was also determined in culture supernatants by GC/MS analysis after derivatization with pentafluorobenzyl bromide. Some strains were differentiated by the PFGE patterns of SpeI digests and by sequence analyses of the lsc and the ppiD genes, and the Chinese Gibbsiella strain was most divergent. The newly investigated bacteria as well as Gibbsiella querinecans, Gibbsiella dentisursi and Gibbsiella papilionis, isolated in Britain, Spain, Korea and Japan, are taxonomically related Enterobacteriaceae, tolerate and secrete acetic acid. We therefore propose to unify them in the species Gibbsiella acetica sp. nov. PMID:26071988

  5. Beta-oxidation of 1-[14C]-17-[131I]-iodoheptadecanoic acid following intracoronary injection in humans results in similar release of both tracers

    International Nuclear Information System (INIS)

    Radioiodine labelled 17-iodo-heptadecanoic acid (IHA) is used for non-invasive study of myocardial metabolism in coronary heart disease and cardiomyopathy. In five patients undergoing coronary sinus catheterization, a mixture of about 40 kBg of [123I] NaI was injected into the left coronary artery. During the following 15-min period, frequent blood samples were taken from the aorta and the coronary sinus. In the aqueous phase of the venous blood, 14CO2 and inorganic 131I appeared nearly in parallel, with a peak time of 4-5 min. Moreover, there was no significant back diffusion of IHA and no significant non-specific deiodination detectable. There was myocardial retention of inorganic iodide (123I) injected into the left coronary artery. The data strongly support the premise that lipid turnover through β-oxidation is the rate-limiting step in the externally measured release of iodide after IHA injection, provided that recirculating inorganic radioactive iodide is corrected for. In addition, 15 volunteers were studied using [11C]palmitic acid and [123I]IHA using PET and dynamic planar camera scintigraphy with iodide correction. There was no significant difference between the mean values of the elimination half-times, and also no significant correlation between half-times of both fatty acids for single individuals. (orig.)

  6. Cloud point extraction of plutonium in environmental matrixes coupled to ICPMS and α spectrometry in highly acidic conditions.

    Science.gov (United States)

    Labrecque, Charles; Whitty-Léveillé, Laurence; Larivière, Dominic

    2013-11-01

    A new cloud point extraction procedure has been developed for the quantification of plutonium(IV) in environmental samples. The separation procedure can be either coupled to inductively coupled plasma mass spectrometry (ICPMS) or α spectrometry for plutonium quantification. The method uses a combination of selective ligand (P,P'-di(2-ethylhexyl) methanediphosphonic acid (H2DEH[MDP])) and micelle shielding by bromine formation to enable quantitative extraction of Pu in highly acidic solutions. Cross-optimization of all parameters (nonionic and ionic surfactant, chelating agent, bromate, bromide, and pH) led to optimal of the extraction conditions. Figures of merit of the method for the detection using α spectrometry and ICPMS are reported (limit of detection, limit of quantification, minimal detectable activity, and recovery). Quantitative extractions (>95%) were obtained for a wide variety of aqueous and digested samples (synthetic urine, wastewater, drinking water, seawater, and soil samples). The method features the first successful coupling between α spectrometry and cloud point extraction and is the first demonstration of CPE suitability with metaborate fusion as a sample preparation approach, techniques used extensively in nuclear industries.

  7. Hyaluronic acid fillers with cohesive polydensified matrix for soft-tissue augmentation and rejuvenation: a literature review

    Science.gov (United States)

    Prasetyo, Adri D; Prager, Welf; Rubin, Mark G; Moretti, Ernesto A; Nikolis, Andreas

    2016-01-01

    Background Cohesive monophasic polydensified fillers show unique viscoelastic properties and variable density of hyaluronic acid, allowing for a homogeneous tissue integration and distribution of the material. Objective The aim of this paper was to review the clinical data regarding the performance, tolerability, and safety of the Belotero® fillers for soft-tissue augmentation and rejuvenation. Methods A literature search was performed up until May 31, 2015 to identify all relevant articles on Belotero® fillers (Basic/Balance, Hydro, Soft, Intense, Volume) and equivalent products (Esthélis®, Mesolis®, Fortélis®, Modélis®). Results This comprehensive review included 26 papers. Findings from three randomized controlled trials showed a greater reduction in nasolabial fold severity with Belotero® Basic/Balance than with collagen (at 8, 12, 16, and 24 weeks, n=118) and Restylane® (at 4 weeks, n=40), and higher patient satisfaction with Belotero® Intense than with Perlane® (at 2 weeks, n=20). With Belotero® Basic/Balance, an improvement of at least 1 point on the severity scale can be expected in ~80% of patients 1–6 months after injection, with an effect still visible at 8–12 months. Positive findings were also reported with Belotero® Volume (no reduction in hyaluronic acid volume at 12 months, as demonstrated by magnetic resonance imaging), Soft (improvement in the esthetic outcomes when used in a sequential approach), and Hydro (improvement in skin appearance in all patients). The most common adverse effects were mild-to-moderate erythema, edema, and hematoma, most of which were temporary. There were no reports of Tyndall effect, nodules, granulomas, or tissue necrosis. Conclusion Clinical evidence indicates sustainable esthetic effects, good safety profile, and long-term tolerability of the Belotero® fillers, particularly Belotero® Basic/Balance and Intense. PMID:27660479

  8. Hyaluronic acid fillers with cohesive polydensified matrix for soft-tissue augmentation and rejuvenation: a literature review

    Science.gov (United States)

    Prasetyo, Adri D; Prager, Welf; Rubin, Mark G; Moretti, Ernesto A; Nikolis, Andreas

    2016-01-01

    Background Cohesive monophasic polydensified fillers show unique viscoelastic properties and variable density of hyaluronic acid, allowing for a homogeneous tissue integration and distribution of the material. Objective The aim of this paper was to review the clinical data regarding the performance, tolerability, and safety of the Belotero® fillers for soft-tissue augmentation and rejuvenation. Methods A literature search was performed up until May 31, 2015 to identify all relevant articles on Belotero® fillers (Basic/Balance, Hydro, Soft, Intense, Volume) and equivalent products (Esthélis®, Mesolis®, Fortélis®, Modélis®). Results This comprehensive review included 26 papers. Findings from three randomized controlled trials showed a greater reduction in nasolabial fold severity with Belotero® Basic/Balance than with collagen (at 8, 12, 16, and 24 weeks, n=118) and Restylane® (at 4 weeks, n=40), and higher patient satisfaction with Belotero® Intense than with Perlane® (at 2 weeks, n=20). With Belotero® Basic/Balance, an improvement of at least 1 point on the severity scale can be expected in ~80% of patients 1–6 months after injection, with an effect still visible at 8–12 months. Positive findings were also reported with Belotero® Volume (no reduction in hyaluronic acid volume at 12 months, as demonstrated by magnetic resonance imaging), Soft (improvement in the esthetic outcomes when used in a sequential approach), and Hydro (improvement in skin appearance in all patients). The most common adverse effects were mild-to-moderate erythema, edema, and hematoma, most of which were temporary. There were no reports of Tyndall effect, nodules, granulomas, or tissue necrosis. Conclusion Clinical evidence indicates sustainable esthetic effects, good safety profile, and long-term tolerability of the Belotero® fillers, particularly Belotero® Basic/Balance and Intense.

  9. Improving thermal stability and light fastness of Acid Red 114 by incorporating its anions in a ZnAl-layered double hydroxides matrix

    Institute of Scientific and Technical Information of China (English)

    Haifeng Zhu; Liren Wang; Pinggui Tang; Yongjun Feng; Dianqing Li

    2012-01-01

    Incorporation of anions of Acid Red 114 dye (1,3-naphthalenedisulfonic acid,8-[2-[3,3'-dimethyl-4'-[2-[4-[[(4-methylphenyl)sulfonyl]oxy] phenyl]diazenyl] [1,1'-biphenyl]-4-yl]diazenyl]-7-hydroxy-,disodium salt) (denoted as NPDA) into ZnAl-layered double hydroxides (LDHs) has been carried out by an anionexchange method in an effort to improve their thermal stability and light fastness.After intercalation of NPDA anions,the interlayer distance of the LDHs increases from 0.87 to 2.18nm,confirming their incorporation into the interlayer galleries of the LDHs host.Infrared spectroscopy and thermogravimetric analysis revealed the presence of host-guest interactions between LDHs layers and NPDA anions.The thermal stability of NPDA and ZnAl-NPDA-LDHs was compared by thermogravimetric-differential thermal analysis,UV-visible spectroscopy and infrared spectroscopy.It was found that the thermal stability of NPDA anions was markedly improved by incorporation into the ZnAl-LDHs matrix,while the light fastness was also enhanced.

  10. Synergistic Chondroprotective Effect of α-Tocopherol, Ascorbic Acid, and Selenium as well as Glucosamine and Chondroitin on Oxidant Induced Cell Death and Inhibition of Matrix Metalloproteinase-3—Studies in Cultured Chondrocytes

    Directory of Open Access Journals (Sweden)

    Anne-Christi Graeser

    2009-12-01

    Full Text Available Overproduction of reactive oxygen species and impaired antioxidant defence accompanied by chronic inflammatory processes may impair joint health. Pro-inflammatory cytokines such as interleukin-1β (IL-1β and tumor necrosis factor alpha (TNF-α stimulate the expression of metalloproteinases which degrade the extracellular matrix. Little is known regarding the potential synergistic effects of natural compounds such as α-tocopherol (α-toc, ascorbic acid (AA and selenium (Se on oxidant induced cell death. Furthermore studies regarding the metalloproteinase-3 inhibitory activity of glucosamine sulfate (GS and chondroitin sulfate (CS are scarce. Therefore we have studied the effect of α-toc (0.1–2.5 µmol/L, AA (10–50 µmol/L and Se (1–50 nmol/L on t-butyl hydroperoxide (t-BHP, 100–500 µmol/L-induced cell death in SW1353 chondrocytes. Furthermore we have determined the effect of GS and CS alone (100–500 µmol/L each and in combination on MMP3 mRNA levels and MMP3 secretion in IL-1β stimulated chondrocytes. A combination of α-toc, AA, and Se was more potent in counteracting t-BHP-induced cytotoxicity as compared to the single compounds. Similarly a combination of CS and GS was more effective in inhibiting MMP3 gene expression and secretion than the single components. The inhibition of MMP3 secretion due to GS plus CS was accompanied by a decrease in TNF-α production. Combining natural compounds such as α-toc, AA, and Se as well as GS and CS seems to be a promising strategy to combat oxidative stress and cytokine induced matrix degradation in chondrocytes.

  11. Antioxidative activity of 3,4-dihydroxyplienylacetic acid and α-tocopherol on the triglyceride matrix of olive oil. Effect of acidity.

    Directory of Open Access Journals (Sweden)

    Blekas, Georgios

    1998-02-01

    Full Text Available Minor constituents of virgin olive oil are important for the remarkable stability of the oil in autoxidation, but the exact role and the extent to which each antioxidant factor contributes to the total antioxidant effect has not been thoroughly Investigated. In this study the role of α-tocopherol is explored at various acidity levels and at low concentrations of ortho-diphenols. A substrate of olive oil triacylglycerols devoid of prooxidant or antioxidant constituents was prepared from refined olive oil by column chromatography To tills substrate, slightly oxidized, the additives (oleic acid, 3,4-dihydroxyphenylacetic acid and α-tocopherol were added and the stability was assessed by periodical measurements of peroxide values. It was found that free fatty adds reduce mainly the protective activity of the ortho-diphenol. It is also concluded that α-tocopherol has a synergistic effect with the ortho-diphenols and contributes significantly to the retardation of peroxide formation. This is Important for oils poor in ortho-diphenols.

    Los constituyentes menores del aceite de oliva virgen son importantes para la notable estabilidad del aceite en la autooxidación, pero el papel exacto y el alcance con que cada factor antioxidante contribuye al efecto antioxidante total no ha sido investigado a fondo. En este estudio el papel del α-tocoferol es examinado a varios niveles de acidez y a baja concentraciones de o-difenoles. Un sustrato de triacilgliceroles de aceite de oliva desprovisto de constituyentes prooxidantes o antioxidantes fue preparado a partir de aceite de oliva refinado mediante cromatografía en columna. A este sustrato, un poco oxidado, los aditivos (ácido oleico, ácido 3,4-dihidroxifenilacético y α-tocoferol fueron añadidos y la estabilidad fue calculada mediante medidas periódicas del índice de peróxido. Se encontró que los ácidos grasos libres reducen principalmente la actividad protectora de los orto-difenoles. Se

  12. Matrix tablets based on thiolated poly(acrylic acid): pH-dependent variation in disintegration and mucoadhesion.

    Science.gov (United States)

    Guggi, Davide; Marschütz, Michaela K; Bernkop-Schnürch, Andreas

    2004-04-15

    This study examined the influence of the pH on the mucoadhesive and cohesive properties of polyarcylic acid (PAA) and thiolated PAA. The pH of PAA (molecular mass: 450 kDa) and of a corresponding PAA-cysteine conjugate was adjusted to 3, 4, 5, 6, 7 and 8. The amount of immobilised thiol groups and disulfide bonds was determined via Ellman's reagent. Tablets were compressed out of each pH-batch of both thiolated and unmodified PAA and the swelling behaviour, the disintegration time and the mucoadhesiveness were evaluated. The amount of thiol/disulfide groups per gram thiolated PAA of pH 3 and pH 8 was determined to be 332 +/- 94 micromol and 162 +/- 46 micromol, respectively. The thiolated PAA tablets displayed a minimum four-fold higher water uptake compared to unmodified PAA tablets. A faster and higher water uptake of both polymer types was observed above pH 5. Thiolated polymer tablets showed a 3-20-fold more prolonged disintegration time than unmodified PAA tablets. The cohesiveness of PAA-cysteine conjugate increased at higher pH, whereas the unmodified PAA behaved inversely. A 3-7-fold stronger mucoadhesiveness was observed for the PAA-cysteine conjugate tablets compared to unmodified PAA tablets. For both thiolated and unmodified polymer the mucoadhesiveness was 2-4-fold enhanced below pH 5. The difference in mucoadhesion between the two polymer types was most pronounced at these lower pH values. In this study substantial information regarding the pH-dependence of mucoadhesion and cohesion of unmodified polyacrylates and of thiolated polyacrylates is provided, representing helpful basic information for an ameliorated deployment of these polymers. PMID:15072786

  13. ZmPUMP encodes a fully functional monocot plant uncoupling mitochondrial protein whose affinity to fatty acid is increased with the introduction of a His pair at the second matrix loop

    International Nuclear Information System (INIS)

    Uncoupling proteins (UCPs) are specialized mitochondrial transporter proteins that uncouple respiration from ATP synthesis. In this study, cDNA encoding maize uncoupling protein (ZmPUMP) was expressed in Escherichia coli and recombinant ZmPUMP reconstituted in liposomes. ZmPUMP activity was associated with a linoleic acid (LA)-mediated H+ efflux with K m of 56.36 ± 0.27 μM and V max of 66.9 μmol H+ min-1 (mg prot)-1. LA-mediated H+ fluxes were sensitive to ATP inhibition with K i of 2.61 ± 0.36 mM (at pH 7.2), a value similar to those for dicot UCPs. ZmPUMP was also used to investigate the importance of a histidine pair present in the second matrix loop of mammalian UCP1 and absent in plant UCPs. ZmPUMP with introduced His pair (Lys155His and Ala157His) displayed a 1.55-fold increase in LA-affinity while its activity remained unchanged. Our data indicate conserved properties of plant UCPs and suggest an enhancing but not essential role of the histidine pair in proton transport mechanism

  14. Matrix string interactions

    OpenAIRE

    Periwal, Vipul; Tafjord, Oyvind

    1998-01-01

    String configurations have been identified in compactified Matrix theory at vanishing string coupling. We show how the interactions of these strings are determined by the Yang-Mills gauge field on the worldsheet. At finite string coupling, this suggests the underlying dynamics is not well-approximated as a theory of strings. This may explain why string perturbation theory diverges badly, while Matrix string perturbation theory presumably has a perturbative expansion with properties similar to...

  15. Alpha-amylase from germinating soybean (Glycine max) seeds--purification, characterization and sequential similarity of conserved and catalytic amino acid residues.

    Science.gov (United States)

    Kumari, Arpana; Singh, Vinay Kumar; Fitter, Jörg; Polen, Tino; Kayastha, Arvind M

    2010-10-01

    Starch hydrolyzing amylase from germinated soybeans seeds (Glycine max) has been purified 400-fold to electrophoretic homogeneity with a final specific activity of 384 units/mg. SDS-PAGE of the final preparation revealed a single protein band of 100 kDa, whereas molecular mass was determined to be 84 kDa by MALDI-TOF and gel filtration on Superdex-200 (FPLC). The enzyme exhibited maximum activity at pH 5.5 and a pI value of 4.85. The energy of activation was determined to be 6.09 kcal/mol in the temperature range 25-85 degrees C. Apparent Michaelis constant (K(m)((app))) for starch was 0.71 mg/mL and turnover number (k(cat)) was 280 s(-1) in 50 mM sodium acetate buffer, pH 5.5. Thermal inactivation studies at 85 degrees C showed first-order kinetics with rate constant (k) equal to 0.0063 min(-1). Soybean alpha-amylase showed high specificity for its primary substrate starch. High similarity of soybean alpha-amylase with known amylases suggests that this alpha-amylase belongs to glycosyl hydrolase family 13. Cereal alpha-amylases have gained importance due to their compatibility for biotechnological applications. Wide availability and easy purification protocol make soybean as an attractive alternative for plant alpha-amylase. Soybean can be used as commercially viable source of alpha-amylase for various industrial applications. PMID:20655076

  16. Reduction of inflammatory responses and enhancement of extracellular matrix formation by vanillin-incorporated poly(lactic-co-glycolic acid) scaffolds.

    Science.gov (United States)

    Lee, Yujung; Kwon, Jeongil; Khang, Gilson; Lee, Dongwon

    2012-10-01

    Vanillin is one of the major components of vanilla, a commonly used flavoring agent and preservative and is known to exert potent antioxidant and anti-inflammatory activities. In this work, vanillin-incorporated poly(lactic-co-glycolic acid) (PLGA) films and scaffolds were fabricated to evaluate the effects of vanillin on the inflammatory responses and extracellular matrix (ECM) formation in vitro and in vivo. The incorporation of vanillin to PLGA films induced hydrophilic nature, resulting in the higher cell attachment and proliferation than the pure PLGA film. Vanillin also reduced the generation of reactive oxygen species (ROS) in cells cultured on the pure PLGA film and significantly inhibited the PLGA-induced inflammatory responses in vivo, evidenced by the reduced accumulation of inflammatory cells and thinner fibrous capsules. The effects of vanillin on the ECM formation were evaluated using annulus fibrous (AF) cell-seeded porous PLGA/vanillin scaffolds. PLGA/vanillin scaffolds elicited the more production of glycosaminoglycan and collagen than the pure PLGA scaffold, in a concentration-dependent manner. Based on the low level of inflammatory responses and enhanced ECM formation, vanillin-incorporated PLGA constructs make them promising candidates in the future biomedical applications.

  17. Caffeic Acid Phenethyl Ester Inhibits Oral Cancer Cell Metastasis by Regulating Matrix Metalloproteinase-2 and the Mitogen-Activated Protein Kinase Pathway

    Directory of Open Access Journals (Sweden)

    Chih-Yu Peng

    2012-01-01

    Full Text Available Caffeic acid phenethyl ester (CAPE, an active component extracted from honeybee hives, exhibits anti-inflammatory and anticancer activities. However, the molecular mechanism by which CAPE affects oral cancer cell metastasis has yet to be elucidated. In this study, we investigated the potential mechanisms underlying the effects of CAPE on the invasive ability of SCC-9 oral cancer cells. Results showed that CAPE attenuated SCC-9 cell migration and invasion at noncytotoxic concentrations (0 μM to 40 μM. Western blot and gelatin zymography analysis findings further indicated that CAPE downregulated matrix metalloproteinase-2 (MMP-2 protein expression and inhibited its enzymatic activity. CAPE exerted its inhibitory effects on MMP-2 expression and activity by upregulating tissue inhibitor of metalloproteinase-2 (TIMP-2 and potently decreased migration by reducing focal adhesion kinase (FAK phosphorylation and the activation of its downstream signaling molecules p38/MAPK and JNK. These data indicate that CAPE could potentially be used as a chemoagent to prevent oral cancer metastasis.

  18. Amino acid properties conserved in molecular evolution.

    Directory of Open Access Journals (Sweden)

    Witold R Rudnicki

    Full Text Available That amino acid properties are responsible for the way protein molecules evolve is natural and is also reasonably well supported both by the structure of the genetic code and, to a large extent, by the experimental measures of the amino acid similarity. Nevertheless, there remains a significant gap between observed similarity matrices and their reconstructions from amino acid properties. Therefore, we introduce a simple theoretical model of amino acid similarity matrices, which allows splitting the matrix into two parts - one that depends only on mutabilities of amino acids and another that depends on pairwise similarities between them. Then the new synthetic amino acid properties are derived from the pairwise similarities and used to reconstruct similarity matrices covering a wide range of information entropies. Our model allows us to explain up to 94% of the variability in the BLOSUM family of the amino acids similarity matrices in terms of amino acid properties. The new properties derived from amino acid similarity matrices correlate highly with properties known to be important for molecular evolution such as hydrophobicity, size, shape and charge of amino acids. This result closes the gap in our understanding of the influence of amino acids on evolution at the molecular level. The methods were applied to the single family of similarity matrices used often in general sequence homology searches, but it is general and can be used also for more specific matrices. The new synthetic properties can be used in analyzes of protein sequences in various biological applications.

  19. Matrix calculus

    CERN Document Server

    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

  20. Sinapinic acid-directed synthesis of gold nanoclusters and their application to quantitative matrix-assisted laser desorption/ionization mass spectrometry

    Science.gov (United States)

    Chen, Tzu-Heng; Yu, Cheng-Ju; Tseng, Wei-Lung

    2014-01-01

    Core etching of gold nanoparticles (AuNPs) into smaller-sized clusters is a classic method for fabricating gold nanoclusters (AuNCs). The top down-based synthesis of AuNCs includes two steps: (i) reducing the Au3+ precursor solution to generate AuNPs in the presence of protecting ligands and (ii) core etching of the formed AuNPs into the AuNCs via ligand exchange. For the first time, this paper describes a one-step approach for preparing AuNCs using a top down approach. The sinapinic acid (SA)-induced formation of the AuNCs involved a three-step reaction process. First, large AuNPs (>200 nm) were quickly formed after mixing SA and the Au3+ precursor solution. Second, excess SA molecules self-assembled on the NP surface, and large AuNPs were etched to small AuNPs via electrostatic repulsion between the neighboring SA molecules. Finally, SA-induced core etching of the AuNPs resulted in the formation of the AuNCs within 70 min. Furthermore, we showed that the presence of the AuNCs in SA was capable of suppressing crystal growth and eliminating the coffee-ring effect. Thus, proteins can be successfully quantified using the SA-AuNCs as matrices for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Compared with using SA as matrices, the SA-AuNCs offered substantial advantages for improving shot-to-shot reproducibility and enhancing the ionization efficiency of proteins.Core etching of gold nanoparticles (AuNPs) into smaller-sized clusters is a classic method for fabricating gold nanoclusters (AuNCs). The top down-based synthesis of AuNCs includes two steps: (i) reducing the Au3+ precursor solution to generate AuNPs in the presence of protecting ligands and (ii) core etching of the formed AuNPs into the AuNCs via ligand exchange. For the first time, this paper describes a one-step approach for preparing AuNCs using a top down approach. The sinapinic acid (SA)-induced formation of the AuNCs involved a three-step reaction process. First, large

  1. Salvianolic Acid B Down-regulates Matrix Metalloproteinase-9 Activity and Expression in Tumor Necrosis Factor-α-induced Human Coronary Artery Endothelial Cells

    Institute of Scientific and Technical Information of China (English)

    Le Ma; Yun-Qian Guan; Zhong-Dong Du

    2015-01-01

    Background:Salvianolic acid B (Sal B) is a bioactive water-soluble compound of Salviae miltiorrhizae,a traditional herbal medicine that has been used clinically tor the treatment of cardiovascular diseases.This study sought to evaluate the effect of Sal B on matrix metalloproteinase-9 (MMP-9) and on the underlying mechanisms in tumor necrosis factor-α (TNF-α)-activated human coronary artery endothelial cells (HCAECs),a cell model of Kawasaki disease.Methods:HCAECs were pretreated with 1 l0 μmol/L of Sal B,and then stimulated by TNF-α at different time points.The protein expression and activity of MMP-9 were determined by Western blot assay and gelatin zymogram assay,respectively.Nuclear factor-κB (NF-κB) activation was detected with immunofluorescence,electrophoretic mobility shift assay,and Western blot assay.Protein expression levels of mitogen-activated protein kinase (c-Jun N-terminal kinase [JNK],extra-cellular signal-regulated kinase [ERK],and p38) were determined by Western blot assay.Results:After HCAECs were exposed to TNF-α,1-10 μtmol/L Sal B significantly inhibited TNF-α-induced MMP-9 expression and activity.Furthermore,Sal B significantly decreased IκBα phosphorylation and p65 nuclear translocation in HCAECs stimulated with TNF-α for 30 min.In addition,Sal B decreased the phosphorylation of JNK and ERK1/2 proteins in cells treated with TNF-α for 10 min.Conclusions:The data suggested that Sal B suppressed TNF-α-induced MMP-9 expression and activity by blocking the activation of NF-κB,JNK,and ERK1/2 signaling pathways.

  2. Sinapinic acid-directed synthesis of gold nanoclusters and their application to quantitative matrix-assisted laser desorption/ionization mass spectrometry.

    Science.gov (United States)

    Chen, Tzu-Heng; Yu, Cheng-Ju; Tseng, Wei-Lung

    2014-01-01

    Core etching of gold nanoparticles (AuNPs) into smaller-sized clusters is a classic method for fabricating gold nanoclusters (AuNCs). The top down-based synthesis of AuNCs includes two steps: (i) reducing the Au(3+) precursor solution to generate AuNPs in the presence of protecting ligands and (ii) core etching of the formed AuNPs into the AuNCs via ligand exchange. For the first time, this paper describes a one-step approach for preparing AuNCs using a top down approach. The sinapinic acid (SA)-induced formation of the AuNCs involved a three-step reaction process. First, large AuNPs (>200 nm) were quickly formed after mixing SA and the Au(3+) precursor solution. Second, excess SA molecules self-assembled on the NP surface, and large AuNPs were etched to small AuNPs via electrostatic repulsion between the neighboring SA molecules. Finally, SA-induced core etching of the AuNPs resulted in the formation of the AuNCs within 70 min. Furthermore, we showed that the presence of the AuNCs in SA was capable of suppressing crystal growth and eliminating the coffee-ring effect. Thus, proteins can be successfully quantified using the SA-AuNCs as matrices for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Compared with using SA as matrices, the SA-AuNCs offered substantial advantages for improving shot-to-shot reproducibility and enhancing the ionization efficiency of proteins. PMID:24288017

  3. All-trans retinoic acid regulates the expression of the extracellular matrix protein fibulin-1 in the guinea pig sclera and human scleral fibroblasts

    Science.gov (United States)

    Li, Chuanxu; McFadden, Sally A.; Morgan, Ian; Cui, Dongmei; Hu, Jianmin; Wan, Wenjuan

    2010-01-01

    Purpose Fibulin-1 (FBLN1) mRNA is expressed in human sclera and is an important adhesion modulatory protein that can affect cell–matrix interactions and tissue remodeling. Scleral remodeling is influenced by all-trans retinoic acid (RA). Our purpose was to confirm the presence of fibulin-1 protein in guinea pig sclera and investigate the effect of RA on the expression of fibulin-1 in guinea pig sclera in vivo and in cultured human scleral fibroblasts (HSFs). Methods Confocal fluorescence microscopy was used to study fibulin-1 and aggrecan expression and localization in sclera from control guinea pigs and in animals given RA by daily gavage from 4 to 8 days of age. The effects of RA (from 10−9 to 10−5 M) on fibulin-1 expression in HSFs were observed by immunohistochemistry and assayed by real-time PCR and western blot analysis. Results Fibulin-1 protein expression was detected by confocal fluorescence microscopy in guinea pig sclera and in cultured HSFs. Upregulation of fibulin-1 in scleral tissue was observed after feeding with RA. In vitro, the level of Fbln1 mRNA was increased after treatment of HSFs with RA (at concentrations of 10−8 to 10−6 M; p<0.001), with a maximum effect at 10−7 M. Fibulin-1 protein levels were significantly increased after treatment of HSFs with 10−7 M of RA for 24 or 48 h (p<0.05). Conclusions Fibulin-1 protein was expressed in guinea pig sclera and cultured HSFs. Expression was regulated by RA, a molecule known to be involved in the regulation of eye growth. Further studies on the role of fibulin-1 in the regulation of eye growth, including during the development of myopia, are therefore warranted. PMID:20405022

  4. Comparison of cellular effects of starch-coated SPIONs and poly(lactic-co-glycolic acid) matrix nanoparticles on human monocytes

    Science.gov (United States)

    Gonnissen, Dominik; Qu, Ying; Langer, Klaus; Öztürk, Cengiz; Zhao, Yuliang; Chen, Chunying; Seebohm, Guiscard; Düfer, Martina; Fuchs, Harald; Galla, Hans-Joachim; Riehemann, Kristina

    2016-01-01

    Within the last years, progress has been made in the knowledge of the properties of medically used nanoparticles and their toxic effects, but still, little is known about their influence on cellular processes of immune cells. The aim of our comparative study was to present the influence of two different nanoparticle types on subcellular processes of primary monocytes and the leukemic monocyte cell line MM6. We used core-shell starch-coated superparamagnetic iron oxide nanoparticles (SPIONs) and matrix poly(lactic-co-glycolic acid) (PLGA) nanoparticles for our experiments. In addition to typical biocompatibility testing like the detection of necrosis or secretion of interleukins (ILs), we investigated the impact of these nanoparticles on the actin cytoskeleton and the two voltage-gated potassium channels Kv1.3 and Kv7.1. Induction of necrosis was not seen for PLGA nanoparticles and SPIONs in primary monocytes and MM6 cells. Likewise, no alteration in secretion of IL-1β and IL-10 was detected under the same experimental conditions. In contrast, IL-6 secretion was exclusively downregulated in primary monocytes after contact with both nanoparticles. Two-electrode voltage clamp experiments revealed that both nanoparticles reduce currents of the aforementioned potassium channels. The two nanoparticles differed significantly in their impact on the actin cytoskeleton, demonstrated via atomic force microscopy elasticity measurement and phalloidin staining. While SPIONs led to the disruption of the respective cytoskeleton, PLGA did not show any influence in both experimental setups. The difference in the effects on ion channels and the actin cytoskeleton suggests that nanoparticles affect these subcellular components via different pathways. Our data indicate that the alteration of the cytoskeleton and the effect on ion channels are new parameters that describe the influence of nanoparticles on cells. The results are highly relevant for medical application and further

  5. EMRE Is a Matrix Ca(2+) Sensor that Governs Gatekeeping of the Mitochondrial Ca(2+) Uniporter.

    Science.gov (United States)

    Vais, Horia; Mallilankaraman, Karthik; Mak, Don-On Daniel; Hoff, Henry; Payne, Riley; Tanis, Jessica E; Foskett, J Kevin

    2016-01-26

    The mitochondrial uniporter (MCU) is an ion channel that mediates Ca(2+) uptake into the matrix to regulate metabolism, cell death, and cytoplasmic Ca(2+) signaling. Matrix Ca(2+) concentration is similar to that in cytoplasm, despite an enormous driving force for entry, but the mechanisms that prevent mitochondrial Ca(2+) overload are unclear. Here, we show that MCU channel activity is governed by matrix Ca(2+) concentration through EMRE. Deletion or charge neutralization of its matrix-localized acidic C terminus abolishes matrix Ca(2+) inhibition of MCU Ca(2+) currents, resulting in MCU channel activation, enhanced mitochondrial Ca(2+) uptake, and constitutively elevated matrix Ca(2+) concentration. EMRE-dependent regulation of MCU channel activity requires intermembrane space-localized MICU1, MICU2, and cytoplasmic Ca(2+). Thus, mitochondria are protected from Ca(2+) depletion and Ca(2+) overload by a unique molecular complex that involves Ca(2+) sensors on both sides of the inner mitochondrial membrane, coupled through EMRE.

  6. A toolbox for representational similarity analysis.

    OpenAIRE

    Hamed Nili; Cai Wingfield; Alexander Walther; Li Su; William Marslen-Wilson; Nikolaus Kriegeskorte

    2014-01-01

    Neuronal population codes are increasingly being investigated with multivariate pattern-information analyses. A key challenge is to use measured brain-activity patterns to test computational models of brain information processing. One approach to this problem is representational similarity analysis (RSA), which characterizes a representation in a brain or computational model by the distance matrix of the response patterns elicited by a set of stimuli. The representational distance matrix enca...

  7. A toolbox for representational similarity analysis

    OpenAIRE

    Nili, Hamed; Wingfield, Cai; Walther, Alexander; Su, Li; Marslen-Wilson, William; KRIEGESKORTE, Nikolaus

    2014-01-01

    Neuronal population codes are increasingly being investigated with multivariate pattern-information analyses. A key challenge is to use measured brain-activity patterns to test computational models of brain information processing. One approach to this problem is representational similarity analysis (RSA), which characterizes a representation in a brain or computational model by the distance matrix of the response patterns elicited by a set of stimuli. The representational distance matrix enca...

  8. Textual Spatial Cosine Similarity

    OpenAIRE

    Crocetti, Giancarlo

    2015-01-01

    When dealing with document similarity many methods exist today, like cosine similarity. More complex methods are also available based on the semantic analysis of textual information, which are computationally expensive and rarely used in the real time feeding of content as in enterprise-wide search environments. To address these real-time constraints, we developed a new measure of document similarity called Textual Spatial Cosine Similarity, which is able to detect similitude at the semantic ...

  9. Protein-protein interaction based on pairwise similarity

    Directory of Open Access Journals (Sweden)

    Zaki Nazar

    2009-05-01

    Full Text Available Abstract Background Protein-protein interaction (PPI is essential to most biological processes. Abnormal interactions may have implications in a number of neurological syndromes. Given that the association and dissociation of protein molecules is crucial, computational tools capable of effectively identifying PPI are desirable. In this paper, we propose a simple yet effective method to detect PPI based on pairwise similarity and using only the primary structure of the protein. The PPI based on Pairwise Similarity (PPI-PS method consists of a representation of each protein sequence by a vector of pairwise similarities against large subsequences of amino acids created by a shifting window which passes over concatenated protein training sequences. Each coordinate of this vector is typically the E-value of the Smith-Waterman score. These vectors are then used to compute the kernel matrix which will be exploited in conjunction with support vector machines. Results To assess the ability of the proposed method to recognize the difference between "interacted" and "non-interacted" proteins pairs, we applied it on different datasets from the available yeast saccharomyces cerevisiae protein interaction. The proposed method achieved reasonable improvement over the existing state-of-the-art methods for PPI prediction. Conclusion Pairwise similarity score provides a relevant measure of similarity between protein sequences. This similarity incorporates biological knowledge about proteins and it is extremely powerful when combined with support vector machine to predict PPI.

  10. Sequence-specific nucleic acid mobility using a reversible block copolymer gel matrix and DNA amphiphiles (lipid-DNA) in capillary and microfluidic electrophoretic separations.

    Science.gov (United States)

    Wagler, Patrick; Minero, Gabriel Antonio S; Tangen, Uwe; de Vries, Jan Willem; Prusty, Deepak; Kwak, Minseok; Herrmann, Andreas; McCaskill, John S

    2015-10-01

    Reversible noncovalent but sequence-dependent attachment of DNA to gels is shown to allow programmable mobility processing of DNA populations. The covalent attachment of DNA oligomers to polyacrylamide gels using acrydite-modified oligonucleotides has enabled sequence-specific mobility assays for DNA in gel electrophoresis: sequences binding to the immobilized DNA are delayed in their migration. Such a system has been used for example to construct complex DNA filters facilitating DNA computations. However, these gels are formed irreversibly and the choice of immobilized sequences is made once off during fabrication. In this work, we demonstrate the reversible self-assembly of gels combined with amphiphilic DNA molecules, which exhibit hydrophobic hydrocarbon chains attached to the nucleobase. This amphiphilic DNA, which we term lipid-DNA, is synthesized in advance and is blended into a block copolymer gel to induce sequence-dependent DNA retention during electrophoresis. Furthermore, we demonstrate and characterize the programmable mobility shift of matching DNA in such reversible gels both in thin films and microchannels using microelectrode arrays. Such sequence selective separation may be employed to select nucleic acid sequences of similar length from a mixture via local electronics, a basic functionality that can be employed in novel electronic chemical cell designs and other DNA information-processing systems. PMID:26095642

  11. Approximate similarity search

    OpenAIRE

    Amato, Giuseppe

    2000-01-01

    Similarity searching is fundamental in various application areas. Recently it has attracted much attention in the database community because of the growing need to deal with large volume of data. Consequently, efficiency has become a matter of concern in design. Although much has been done to develop structures able to perform fast similarity search, results are still not satisfactory, and more research is needed. The performance of similarity search for complex features deteriorates and does...

  12. Similarity transformations of MAPs

    Directory of Open Access Journals (Sweden)

    Andersen Allan T.

    1999-01-01

    Full Text Available We introduce the notion of similar Markovian Arrival Processes (MAPs and show that the event stationary point processes related to two similar MAPs are stochastically equivalent. This holds true for the time stationary point processes too. We show that several well known stochastical equivalences as e.g. that between the H 2 renewal process and the Interrupted Poisson Process (IPP can be expressed by the similarity transformations of MAPs. In the appendix the valid region of similarity transformations for two-state MAPs is characterized.

  13. Liquid chromatography/electrospray ionization/isotopic dilution mass spectrometry analysis of n-(phosphonomethyl) glycine and mass spectrometry analysis of aminomethyl phosphonic acid in environmental water and vegetation matrixes.

    Science.gov (United States)

    Grey, L; Nguyen, B; Yang, P

    2001-01-01

    A liquid chromatography/electrospray/mass spectrometry (LC/ES/MS) method was developed for the analysis of glyphosate (n-phosphonomethyl glycine) and its metabolite, aminomethyl phosphonic acid (AMPA) using isotope-labelled glyphosate as a method surrogate. Optimized parameters were achieved to derivatize glyphosate and AMPA using 9-fluorenylmethyl chloroformate (FMOC-Cl) in borate buffer prior to a reversed-phase LC analysis. Method spike recovery data obtained using laboratory and real world sample matrixes indicated an excellent correlation between the recovery of the native and isotope-labelled glyphosate. Hence, the first performance-based, isotope dilution MS method with superior precision, accuracy, and data quality was developed for the analysis of glyphosate. There was, however, no observable correlation between the isotope-labelled glyphosate and AMPA. Thus, the use of this procedure for the accurate analysis of AMPA was not supported. Method detection limits established using standard U.S. Environmental Protection Agency protocol were 0.06 and 0.30 microg/L, respectively, for glyphosate and AMPA in water matrixes and 0.11 and 0.53 microg/g, respectively, in vegetation matrixes. Problems, solutions, and the method performance data related to the analysis of chlorine-treated drinking water samples are discussed. Applying this method to other environmental matrixes, e.g., soil, with minimum modifications is possible, assuring accurate, multimedia studies of glyphosate concentration in the environment and the delivery of useful multimedia information for regulatory applications.

  14. Clustering by Pattern Similarity

    Institute of Scientific and Technical Information of China (English)

    Hai-xun Wang; Jian Pei

    2008-01-01

    The task of clustering is to identify classes of similar objects among a set of objects. The definition of similarity varies from one clustering model to another. However, in most of these models the concept of similarity is often based on such metrics as Manhattan distance, Euclidean distance or other Lp distances. In other words, similar objects must have close values in at least a set of dimensions. In this paper, we explore a more general type of similarity. Under the pCluster model we proposed, two objects are similar if they exhibit a coherent pattern on a subset of dimensions. The new similarity concept models a wide range of applications. For instance, in DNA microarray analysis, the expression levels of two genes may rise and fall synchronously in response to a set of environmental stimuli. Although the magnitude of their expression levels may not be close, the patterns they exhibit can be very much alike. Discovery of such clusters of genes is essential in revealing significant connections in gene regulatory networks. E-commerce applications, such as collaborative filtering, can also benefit from the new model, because it is able to capture not only the closeness of values of certain leading indicators but also the closeness of (purchasing, browsing, etc.) patterns exhibited by the customers. In addition to the novel similarity model, this paper also introduces an effective and efficient algorithm to detect such clusters, and we perform tests on several real and synthetic data sets to show its performance.

  15. New Similarity Functions

    DEFF Research Database (Denmark)

    Yazdani, Hossein; Ortiz-Arroyo, Daniel; Kwasnicka, Halina

    2016-01-01

    In data science, there are important parameters that affect the accuracy of the algorithms used. Some of these parameters are: the type of data objects, the membership assignments, and distance or similarity functions. This paper discusses similarity functions as fundamental elements in membership...

  16. Media segmentation using self-similarity decomposition

    Science.gov (United States)

    Foote, Jonathan T.; Cooper, Matthew L.

    2003-01-01

    We present a framework for analyzing the structure of digital media streams. Though our methods work for video, text, and audio, we concentrate on detecting the structure of digital music files. In the first step, spectral data is used to construct a similarity matrix calculated from inter-frame spectral similarity.The digital audio can be robustly segmented by correlating a kernel along the diagonal of the similarity matrix. Once segmented, spectral statistics of each segment are computed. In the second step,segments are clustered based on the self-similarity of their statistics. This reveals the structure of the digital music in a set of segment boundaries and labels. Finally, the music is summarized by selecting clusters with repeated segments throughout the piece. The summaries can be customized for various applications based on the structure of the original music.

  17. Matrix inequalities

    CERN Document Server

    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.

  18. Similar component analysis

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hong; WANG Xin; LI Junwei; CAO Xianguang

    2006-01-01

    A new unsupervised feature extraction method called similar component analysis (SCA) is proposed in this paper. SCA method has a self-aggregation property that the data objects will move towards each other to form clusters through SCA theoretically,which can reveal the inherent pattern of similarity hidden in the dataset. The inputs of SCA are just the pairwise similarities of the dataset,which makes it easier for time series analysis due to the variable length of the time series. Our experimental results on many problems have verified the effectiveness of SCA on some engineering application.

  19. Comparison of cellular effects of starch-coated SPIONs and poly(lactic-co-glycolic acid matrix nanoparticles on human monocytes

    Directory of Open Access Journals (Sweden)

    Gonnissen D

    2016-10-01

    Full Text Available Dominik Gonnissen,1 Ying Qu,1,2 Klaus Langer,3 Cengiz Öztürk,4 Yuliang Zhao,2 Chunying Chen,2 Guiscard Seebohm,5 Martina Düfer,6 Harald Fuchs,1 Hans-Joachim Galla,7 Kristina Riehemann11Center for Nanotechnology, Institute of Physics, University of Münster, Münster, Germany; 2National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing, People’s Republic of China; 3Institute of Pharmaceutical Technology and Biopharmacy, University of Münster, Münster, 4chemicell GmbH, Berlin, 5Department of Cardiovascular Medicine, Institute for Genetics of Heart Diseases, University Hospital Münster, 6Department of Pharmacology, Institute of Pharmaceutical and Medicinal Chemistry, 7Department of Cell Biology/Biophysics, Institute of Biochemistry, University of Münster, Münster, GermanyAbstract: Within the last years, progress has been made in the knowledge of the properties of medically used nanoparticles and their toxic effects, but still, little is known about their influence on cellular processes of immune cells. The aim of our comparative study was to present the influence of two different nanoparticle types on subcellular processes of primary monocytes and the leukemic monocyte cell line MM6. We used core-shell starch-coated superparamagnetic iron oxide nanoparticles (SPIONs and matrix poly(lactic-co-glycolic acid (PLGA nanoparticles for our experiments. In addition to typical biocompatibility testing like the detection of necrosis or secretion of interleukins (ILs, we investigated the impact of these nanoparticles on the actin cytoskeleton and the two voltage-gated potassium channels Kv1.3 and Kv7.1. Induction of necrosis was not seen for PLGA nanoparticles and SPIONs in primary monocytes and MM6 cells. Likewise, no alteration in secretion of IL-1β and IL-10 was detected under the same experimental conditions. In contrast, IL-6 secretion was exclusively downregulated in primary monocytes after contact with both

  20. Stability of similarity measurements for bipartite networks

    CERN Document Server

    Liu, Jian-Guo; Pan, Xue; Guo, Qiang; Zhou, Tao

    2015-01-01

    Similarity is a fundamental measure in network analyses and machine learning algorithms, with wide applications ranging from personalized recommendation to socio-economic dynamics. We argue that an effective similarity measurement should guarantee the stability even under some information loss. With six bipartite networks, we investigate the stabilities of fifteen similarity measurements by comparing the similarity matrixes of two data samples which are randomly divided from original data sets. Results show that, the fifteen measurements can be well classified into three clusters according to their stabilities, and measurements in the same cluster have similar mathematical definitions. In addition, we develop a top-$n$-stability method for personalized recommendation, and find that the unstable similarities would recommend false information to users, and the performance of recommendation would be largely improved by using stable similarity measurements. This work provides a novel dimension to analyze and eval...

  1. Gender similarities and differences.

    Science.gov (United States)

    Hyde, Janet Shibley

    2014-01-01

    Whether men and women are fundamentally different or similar has been debated for more than a century. This review summarizes major theories designed to explain gender differences: evolutionary theories, cognitive social learning theory, sociocultural theory, and expectancy-value theory. The gender similarities hypothesis raises the possibility of theorizing gender similarities. Statistical methods for the analysis of gender differences and similarities are reviewed, including effect sizes, meta-analysis, taxometric analysis, and equivalence testing. Then, relying mainly on evidence from meta-analyses, gender differences are reviewed in cognitive performance (e.g., math performance), personality and social behaviors (e.g., temperament, emotions, aggression, and leadership), and psychological well-being. The evidence on gender differences in variance is summarized. The final sections explore applications of intersectionality and directions for future research.

  2. Gender similarities and differences.

    Science.gov (United States)

    Hyde, Janet Shibley

    2014-01-01

    Whether men and women are fundamentally different or similar has been debated for more than a century. This review summarizes major theories designed to explain gender differences: evolutionary theories, cognitive social learning theory, sociocultural theory, and expectancy-value theory. The gender similarities hypothesis raises the possibility of theorizing gender similarities. Statistical methods for the analysis of gender differences and similarities are reviewed, including effect sizes, meta-analysis, taxometric analysis, and equivalence testing. Then, relying mainly on evidence from meta-analyses, gender differences are reviewed in cognitive performance (e.g., math performance), personality and social behaviors (e.g., temperament, emotions, aggression, and leadership), and psychological well-being. The evidence on gender differences in variance is summarized. The final sections explore applications of intersectionality and directions for future research. PMID:23808917

  3. Identification of Fatty Acids, Phospholipids, and Their Oxidation Products Using Matrix-Assisted Laser Desorption Ionization Mass Spectrometry and Electrospray Ionization Mass Spectrometry

    Science.gov (United States)

    Harmon, Christopher W.; Mang, Stephen A.; Greaves, John; Finlayson-Pitts, Barbara J.

    2010-01-01

    Electrospray ionization mass spectrometry (ESI-MS) and matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) have found increasing application in the analysis of biological samples. Using these techniques to solve problems in analytical chemistry should be an essential component of the training of undergraduate chemists. We…

  4. Cognitive residues of similarity

    OpenAIRE

    OToole, Stephanie; Keane, Mark T.

    2013-01-01

    What are the cognitive after-effects of making a similarity judgement? What, cognitively, is left behind and what effect might these residues have on subsequent processing? In this paper, we probe for such after-effects using a visual search task, performed after a task in which pictures of real-world objects were compared. So, target objects were first presented in a comparison task (e.g., rate the similarity of this object to another) thus, presumably, modifying some of their features befor...

  5. Matrix analysis

    CERN Document Server

    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...

  6. A novel protein distance matrix based on the minimum arc-length between two amino-acid residues on the surface of a globular protein.

    Science.gov (United States)

    Hall, Damien; Li, Songling; Yamashita, Kazuo; Azuma, Ryuzo; Carver, John A; Standley, Daron M

    2014-06-01

    We present a novel protein distance matrix based on the minimum line of arc between two points on the surface of a protein. Two methods for calculating this distance matrix are developed and contrasted. The first method, which we have called TOPOL, is an approximate rule based algorithm consisting of successive rounds of vector addition. The second method is adapted from the graph theoretic approach of Dijkstra. Both procedures are demonstrated using cytochrome c, a 12,500 Da protein, as a test case. In respect to computational speed and accuracy the TOPOL procedure compares favorably against the more complex method based on shortest path enumeration over a surface manifold grid. Some potential uses of the algorithmic approaches and calculated surface protein distance measurement are discussed. PMID:24589301

  7. 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.

  8. The Qualitative Similarity Hypothesis

    Science.gov (United States)

    Paul, Peter V.; Lee, Chongmin

    2010-01-01

    Evidence is presented for the qualitative similarity hypothesis (QSH) with respect to children and adolescents who are d/Deaf or hard of hearing. The primary focus is on the development of English language and literacy skills, and some information is provided on the acquisition of English as a second language. The QSH is briefly discussed within…

  9. Similarity of molecular shape.

    Science.gov (United States)

    Meyer, A Y; Richards, W G

    1991-10-01

    The similarity of one molecule to another has usually been defined in terms of electron densities or electrostatic potentials or fields. Here it is expressed as a function of the molecular shape. Formulations of similarity (S) reduce to very simple forms, thus rendering the computerised calculation straightforward and fast. 'Elements of similarity' are identified, in the same spirit as 'elements of chirality', except that the former are understood to be variable rather than present-or-absent. Methods are presented which bypass the time-consuming mathematical optimisation of the relative orientation of the molecules. Numerical results are presented and examined, with emphasis on the similarity of isomers. At the extreme, enantiomeric pairs are considered, where it is the dissimilarity (D = 1 - S) that is of consequence. We argue that chiral molecules can be graded by dissimilarity, and show that D is the shape-analog of the 'chirality coefficient', with the simple form of the former opening up numerical access to the latter. PMID:1770379

  10. IR spectrum of CH3CN-BF3 in solid neon: matrix effects on the structure of a Lewis acid-base complex.

    Science.gov (United States)

    Eigner, Audrey A; Rohde, John A; Knutson, Christopher C; Phillips, James A

    2007-02-15

    We have observed several IR bands of CH3CN-BF3 in neon and nitrogen matrices. For the 11B isotopomer in neon matrices, we observed the BF3 symmetric deformation band (nu7) as a doublet at 600 and 603 cm(-1), the BF3 symmetric stretching band (nu6) as a doublet at 833 and 838 cm(-1), the BF3 asymmetric stretching mode (nu13) at 1281 cm(-1) (partially obscured), and the C-N stretching mode (nu2) as a doublet at 2352 and 2356 cm(-1). The nitrogen matrix data are largely consistent with those reported recently, though we do propose a refinement of one band assignment. Comparisons of the frequencies of a few key, structurally sensitive vibrational modes either observed in various condensed-phase environments or calculated for two minimum-energy gas-phase structures indicate that inert matrix media significantly alter the structural properties of CH3CN-BF3. Specifically, the B-N dative bond compresses relative to the gas phase and other concomitant changes occur as well. Furthermore, the frequency shifts depict structural changes that occur across the various matrix hosts in a manner that largely parallels the degree of stabilization offered by these inert media.

  11. Matrix pentagons

    CERN Document Server

    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.

  12. Limiting Similarity Revisited

    OpenAIRE

    Szabo, P; Meszena, G.

    2005-01-01

    We reinvestigate the validity of the limiting similarity principle via numerical simulations of the Lotka-Volterra model. A Gaussian competition kernel is employed to describe decreasing competition with increasing difference in a one-dimensional phenotype variable. The simulations are initiated by a large number of species, evenly distributed along the phenotype axis. Exceptionally, the Gaussian carrying capacity supports coexistence of all species, initially present. In case of any other, d...

  13. Compression-based similarity

    OpenAIRE

    Vitányi, Paul

    2011-01-01

    First we consider pair-wise distances for literal objects consisting of finite binary files. These files are taken to contain all of their meaning, like genomes or books. The distances are based on compression of the objects concerned, normalized, and can be viewed as similarity distances. Second, we consider pair-wise distances between names of objects, like "red" or "christianity." In this case the distances are based on searches of the Internet. Such a search can be performed by any search...

  14. Similar dissection of sets

    CERN Document Server

    Akiyama, Shigeki; Okazaki, Ryotaro; Steiner, Wolfgang; Thuswaldner, Jörg

    2010-01-01

    In 1994, Martin Gardner stated a set of questions concerning the dissection of a square or an equilateral triangle in three similar parts. Meanwhile, Gardner's questions have been generalized and some of them are already solved. In the present paper, we solve more of his questions and treat them in a much more general context. Let $D\\subset \\mathbb{R}^d$ be a given set and let $f_1,...,f_k$ be injective continuous mappings. Does there exist a set $X$ such that $D = X \\cup f_1(X) \\cup ... \\cup f_k(X)$ is satisfied with a non-overlapping union? We prove that such a set $X$ exists for certain choices of $D$ and $\\{f_1,...,f_k\\}$. The solutions $X$ often turn out to be attractors of iterated function systems with condensation in the sense of Barnsley. Coming back to Gardner's setting, we use our theory to prove that an equilateral triangle can be dissected in three similar copies whose areas have ratio $1:1:a$ for $a \\ge (3+\\sqrt{5})/2$.

  15. Self Similar Optical Fiber

    Science.gov (United States)

    Lai, Zheng-Xuan

    This research proposes Self Similar optical fiber (SSF) as a new type of optical fiber. It has a special core that consists of self similar structure. Such a structure is obtained by following the formula for generating iterated function systems (IFS) in Fractal Theory. The resulted SSF can be viewed as a true fractal object in optical fibers. In addition, the method of fabricating SSF makes it possible to generate desired structures exponentially in numbers, whereas it also allows lower scale units in the structure to be reduced in size exponentially. The invention of SSF is expected to greatly ease the production of optical fiber when a large number of small hollow structures are needed in the core of the optical fiber. This dissertation will analyze the core structure of SSF based on fractal theory. Possible properties from the structural characteristics and the corresponding applications are explained. Four SSF samples were obtained through actual fabrication in a laboratory environment. Different from traditional conductive heating fabrication system, I used an in-house designed furnace that incorporated a radiation heating method, and was equipped with automated temperature control system. The obtained samples were examined through spectrum tests. Results from the tests showed that SSF does have the optical property of delivering light in a certain wavelength range. However, SSF as a new type of optical fiber requires a systematic research to find out the theory that explains its structure and the associated optical properties. The fabrication and quality of SSF also needs to be improved for product deployment. As a start of this extensive research, this dissertation work opens the door to a very promising new area in optical fiber research.

  16. Repression by H-NS of genes required for the biosynthesis of the Vibrio cholerae biofilm matrix is modulated by the second messenger cyclic diguanylic acid.

    Science.gov (United States)

    Ayala, Julio C; Wang, Hongxia; Silva, Anisia J; Benitez, Jorge A

    2015-08-01

    Expression of Vibrio cholerae genes required for the biosynthesis of exopolysacchide (vps) and protein (rbm) components of the biofilm matrix is enhanced by cyclic diguanylate (c-di-GMP). In a previous study, we reported that the histone-like nucleoid structuring (H-NS) protein represses the transcription of vpsA, vpsL and vpsT. Here we demonstrate that the regulator VpsT can disrupt repressive H-NS nucleoprotein complexes at the vpsA and vpsL promoters in the presence of c-di-GMP, while H-NS could disrupt the VpsT-promoter complexes in the absence of c-di-GMP. Chromatin immunoprecipitation-Seq showed a remarkable trend for H-NS to cluster at loci involved in biofilm development such as the rbmABCDEF genes. We show that the antagonistic relationship between VpsT and H-NS regulates the expression of the rbmABCDEF cluster. Epistasis analysis demonstrated that VpsT functions as an antirepressor at the rbmA/F, vpsU and vpsA/L promoters. Deletion of vpsT increased H-NS occupancy at these promoters while increasing the c-di-GMP pool had the opposite effect and included the vpsT promoter. The negative effect of c-di-GMP on H-NS occupancy at the vpsT promoter required the regulator VpsR. These results demonstrate that c-di-GMP activates the transcription of genes required for the biosynthesis of the biofilm matrix by triggering a coordinated VpsR- and VpsT-dependent H-NS antirepression cascade.

  17. Image fusion using bi-directional similarity

    Science.gov (United States)

    Bai, Chunshan; Luo, Xiaoyan

    2015-05-01

    Infrared images are widely used in the practical applications to capture abundant information. However, it is still challenging to enhance the infrared image by the visual image. In this paper, we propose an effective method using bidirectional similarity. In the proposed method, we aim to find an optimal solution from many feasible solutions without introducing intermediate image. We employ some priori constraints to meet the requirements of image fusion which can be detailed to preserve both good characteristics in the infrared image and spatial information in the visual image. In the iterative step, we use the matrix with the square of the difference between images to integrate the image holding most information. We call this matrix the bidirectional similarity distance. By the bidirectional similarity distance, we can get the transitive images. Then, we fuse the images according to the weight. Experimental results show that, compared to the traditional image fusion algorithm, fusion images from bidirectional similarity fusion algorithm have greatly improved in the subjective vision, entropy, structural similarity index measurement. We believe that the proposed scheme can have a wide applications.

  18. Localization of an O-glycosylated site in the recombinant barley alpha-amylase 1 produced in yeast and correction of the amino acid sequence using matrix-assisted laser desorption/ionization mass spectrometry of peptide mixtures

    DEFF Research Database (Denmark)

    Andersen, Jens S.; Søgaard, M; Svensson, B;

    1994-01-01

    , and analyzed directly by MALDI-MS. Based on the three mass spectrometric peptide maps, an error in the sequence deduced from cDNA, resulting in a mass difference of 28 Da, was located to a sequence stretch of 5 amino acid residues; furthermore, a dihexose substituent was identified on Thr410. Subsequent Edman...... degradation of two selected peptides isolated from the endoproteinase Lys-C digest corrected the sequence to be Val instead of Ala in position 284 and confirmed the O-glycosylation. These results demonstrate that the direct peptide mixture analysis by MALDI-MS is a rapid and sensitive method for protein......Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) of peptide mixtures was used to characterize recombinant barley alpha-amylase 1, produced in yeast. Three peptide mixtures were generated by cleavage with CNBr, digestion with endoproteinase Lys-C and Asp-N, respectively...

  19. H-Bonding of Sulfuric Acid with Its Decomposition Products: An Infrared Matrix Isolation and Computational Study of the H2SO4·H2O·SO3 Complex.

    Science.gov (United States)

    Rozenberg, Mark; Loewenschuss, Aharon; Nielsen, Claus J

    2016-05-26

    The FTIR matrix isolation spectra of H2SO4 vapors show a group of bands with synchronous growth of their relative intensities which is independent of the water species content of the matrix layer. Their frequency positions indicate that the species they represent is H-bonded and composed of all three components (H2SO4, H2O, and SO3) involved in the vapor decomposition equilibrium of the acid molecule. Structure, stabilization energies, and vibrational frequencies of several H-bonded complexes between these components were considered in B3LYP calculations employing Dunning's correlation-consistent aug-cc-pVTZ basis sets. Correlations between spectral shifts, bond lengths, and H-bond energies were also considered. The best fitting complex is a ring structured 1:1:1 H2SO4·H2O·SO3. The indications are that the complex is formed in the vapor phase and not after deposition. The atmospheric significance may be in its ability to serve as a H-bonding nucleation center even without the presence of additional contaminants. PMID:27135379

  20. Oxidizing gel formulation for nuclear decontamination: rheological and acidic properties of the organic matrix and its ozonolysis; Formulation d'un gel oxydant a matrice organique applicable a la decontamination nucleaire: proprietes rheologiques, acido-basiques et ozonolyse de la matrice

    Energy Technology Data Exchange (ETDEWEB)

    Rouy, E

    2003-10-15

    An acidic and oxidizing gel was formulated with a purely organic matrix, xanthan gum, at low concentrations (1 to 2 wt %). This polymer gel was investigated in various media (aqueous, acidic and ceric) by means of rheology: shear thinning behaviour, thixotropy, yield stress... Evidences of unexpected rheological properties in highly concentrated media show that xanthan is quite convenient for industrial projection of this type of gel on metallic walls in nuclear plants, notwithstanding its time-limited resistance to oxidation (about a few hours). Complexation mechanisms between ceric species and polar sites of the polymer led us to characterise acidic properties of our xanthan sample by potentiometric titration and {sup 1}H NMR techniques. The matrix was finally treated by ozonolysis to suppress organic residues, as required to handle nuclear wastes. In acidic medium, ozonolysis of the gel was achieved successfully while in acidic and ceric medium this process showed limited efficiency, needing further investigation to be clarified. (author)

  1. SOLVENT EFFECT ON EXTRACTION OF GALLIC ACID FROM AMALAKI CHURNA (EMBLICA OFFICINALIS Gaertn. TO REDUCE MATRIX EFFECT USING HPTLC AND UV-SPECTROSCOPY WITH 12 DIFFERENT NATURE SOLVENTS

    Directory of Open Access Journals (Sweden)

    Sukla V.J.

    2012-06-01

    Full Text Available Standardization of Ayurvedic formulations is an important aspect for research in Indian medicine. In this era every Pharma company prefer to use pure extract of component for production of best product in short period of time. The literature survey reveals that no work has been reported for solvent selection of extraction of Ayurvedic drugs. Amalaki is one of the most useable ayurveda drug. So, the present study was selected with an aim to select solvent for extraction of component of interest. Standard for evaluating quality of Amalaki churna by employing various physico-chemical parameters. For solvent selection 12 different nature solvents are selected for extraction. Polar solvent selected are Water, Di methylsulfoxide (DMSO, Ethylene glycol, Acetonitrile, Di methyl formeamide (DMF and Methanol. Non polar solvents are Acetone, Acetic acid, Ethyl acetate, Chloroform, Di ethylether and Toluene. Extraction was done by maceration method. Results are taken by chromatographic and spectrophotometric methods. In observation component was easily extracted with less interfering component in non polar solvent. Gallic acid is component of interest for Amalaki and it is well extracted in Di ethyl ether as per result of chromatography and spectroscopy. Conclusion is that selection of solvent for extraction as per their component of interest from material.

  2. The incorporation of water-soluble gel matrix into bile acid-based microcapsules for the delivery of viable β-cells of the pancreas, in diabetes treatment: biocompatibility and functionality studies.

    Science.gov (United States)

    Mooranian, Armin; Negrulj, Rebecca; Al-Salami, Hani

    2016-02-01

    In recent studies, we microencapsulated pancreatic β-cells using sodium alginate (SA) and poly-L-ornithine (PLO) and the bile acid, ursodeoxycholic acid (UDCA), and tested the morphology and cell viability post-microencapsulation. Cell viability was low probably due to limited strength of the microcapsules. This study aimed to assess a β-cell delivery system which consists of UDCA-based microcapsules incorporated with water-soluble gel matrix. The polyelectrolytes, water-soluble gel (WSG), polystyrenic sulphate (PSS), PLO and polyallylamine (PAA) at ratios 4:1:1:2.5 with or without 4% UDCA, were incorporated into our microcapsules, and cell viability, metabolic profile, cell functionality, insulin production, levels of inflammation, microcapsule morphology, cellular distribution, UDCA partitioning, biocompatibility, thermal and chemical stabilities and the microencapsulation efficiency were examined. The incorporation of UDCA with PSS, PAA and WSG enhanced cell viability per microcapsule (p < 0.05), cellular metabolic profile (p < 0.01) and insulin production (p < 0.01); reduced the inflammatory release TNF-α (p < 0.01), INF-gamma (p < 0.01) and interleukin-6 (IL-6) (p < 0.01); and ceased the production of IL-1β. UDCA, PSS, PAA and WSG addition did not change the microencapsulation efficiency and resulted in biocompatible microcapsules. Our designed microcapsules showed good morphology and desirable insulin production, cell functionality and reduced inflammatory profile suggesting potential applications in diabetes.

  3. Neu1 sialidase and matrix metalloproteinase-9 cross-talk regulates nucleic acid-induced endosomal TOLL-like receptor-7 and -9 activation, cellular signaling and pro-inflammatory responses.

    Science.gov (United States)

    Abdulkhalek, Samar; Szewczuk, Myron R

    2013-11-01

    The precise mechanism(s) by which intracellular TOLL-like receptors (TLRs) become activated by their ligands remains unclear. Here, we report a molecular organizational G-protein coupled receptor (GPCR) signaling platform to potentiate a novel mammalian neuraminidase-1 (Neu1) and matrix metalloproteinase-9 (MMP-9) cross-talk in alliance with neuromedin B GPCR, all of which form a tripartite complex with TLR-7 and -9. siRNA silencing Neu1, MMP-9 and neuromedin-B GPCR in RAW-blue macrophage cells significantly reduced TLR7 imiquimod- and TLR9 ODN1826-induced NF-κB (NF-κB-pSer(536)) activity. Tamiflu, specific MMP-9 inhibitor, neuromedin B receptor specific antagonist BIM23127, and the selective inhibitor of whole heterotrimeric G-protein complex BIM-46174 significantly block nucleic acid-induced TLR-7 and -9 MyD88 recruitment, NF-κB activation and proinflammatory TNFα and MCP-1 cytokine responses. For the first time, Neu1 clearly plays a central role in mediating nucleic acid-induced intracellular TLR activation, and the interactions involving NMBR-MMP9-Neu1 cross-talk constitute a novel intracellular TLR signaling platform that is essential for NF-κB activation and pro-inflammatory responses. PMID:23827939

  4. Efficacy of Ruby Dot Matrix Laser Combined with Tranexamic Acid Tablets in the Treatment of Melasma%红宝石点阵激光联合氨甲环酸治疗黄褐斑临床观察

    Institute of Scientific and Technical Information of China (English)

    张璃; 林孝华; 唐东阳

    2012-01-01

    Objective To observe the clinical therapeutic efficacy of ruby dot matrix laser combined with tranexamic acid tablets in the treatment of melasma. Methods Laser treatment; choice dot matrix pattern, with energy density from 2. 5mJ/mm to 3. 5mJ/mm . Everyone accepted treatment twice one month. One course included 4 times of treatment. Everyone accepted only one course treatment. Tranexamic acid tablets treatment; Everyone was given tranexamic acid tablets 500mg per day, 2 months as 1 course. Everyone accepted 3 courses treatment. The severity and the area of melasma was assessed by two dermatologists using the melasma area severity index ( MASI). At regular in tervals the degree of improvement in pigmentation was reassessed with MASI scores. Effect appearance, recurrence, side-effects were also recorded. Results The 120 patients were followed for 6 ~ 12 months after treatment. 118 patients(98. 33% ) appeared the varying degree facial pigmentation loss. 5 cases(4. 17% ) was cured thoroughly, 74 cases(61.67% ) were cured better than before obviously. And in 39 cases treated for effective. The efficiency was 65. 84%. 37 patients (30. 83% ) showed clinical effect at the half-month treatment, 52 patients (43. 33%) showed clinical effect after one month treatment. Furthermore, only 8 patients(6. 67% ) had recurrences. There were no obvious side-effects of the treatment except a hypomenorrhea in 7 patients. Conclusion Ruby dot matrix laser combined with tranexamic acid tablets is a novel therapy, which is safe and effective in the treatment of melasma.%目的 对红宝石点阵激光联合氨甲环酸片治疗黄褐斑进行临床疗效观察.方法 激光治疗:采用点阵模式,能量密度2.5 ~ 3.5J/cm2,每隔2周治疗1次,2个月为1个疗程;同时口服氨甲环酸片500mg,1次/d,2个月为1个疗程,连续治疗3个疗程;对患者进行黄褐斑皮损面积和严重程度指数(MASI)评分,采用自身治疗前/后对照法进行疗效观察,记录起效

  5. Poly(DL-lactic acid) as a direct compression excipient in controlled release tablets - Part I. Compaction behaviour and release characteristics of poly(DL-lactic acid) matrix tablets

    NARCIS (Netherlands)

    Steendam, R; Lerk, CF

    1998-01-01

    High-molecular weight poly(DL-lactic acid) (PDLA, M-v 85000) was applied as a direct compression excipient in controlled release tablets. PDLA powders with good flowing properties were obtained by milling pre-cooled PDLA granules. Apparent yield pressure values ranged from 44 to 71 MPa for tablettin

  6. Towards Google matrix of brain

    International Nuclear Information System (INIS)

    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 α. The properties of other eigenstates are also analyzed. We discuss further parallels and similarities between the World Wide Web and neuronal networks.

  7. 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.

  8. Mapping of the human dentin matrix acidic phosphoprotein gene (DMP1) to the dentinogenesis imperfecta type II critical region at chromosome 4q21

    Energy Technology Data Exchange (ETDEWEB)

    Aplin, H.M.; Hirst, K.L.; Crosby, A.H.; Dixon, M.J. [Univ. of Manchester (United Kingdom)

    1995-11-20

    Dentinogenesis imperfecta type II (DGI1) is an autosomal dominant disorder of dentin formation, which has been mapped to human chromosome 4q12-q21. The region most likely to contain the DGI1 locus is a 3.2-cM region surrounding the osteopontin (SPP1) locus. Recently, a novel dentin-specific acidic phosphoprotein (dmp1) has been cloned in the rat and mapped to mouse chromosome 5q21. In the current investigation, we have isolated a cosmid containing the human DMP1 gene. The isolation of a short tandem repeat polymorphism at this locus has allowed us to map the DMP1 locus to human chromosome 4q21 and demonstrate that it is tightly linked to DGI1 in two families (Z{sub max} = 11.01, {theta} = 0.001). The creation of a yeast artificial chromosome contig around SPP1 has further allowed us to demonstrate that DMP1 is located within 150 kb of the bone sialoprotein and 490 kb of the SPP1 loci, respectively. DMP1 is therefore a strong candidate for the DGI1 locus. 12 refs., 2 figs., 1 tab.

  9. Estimating similarity of XML Schemas using path similarity measure

    Directory of Open Access Journals (Sweden)

    Veena Trivedi

    2012-07-01

    Full Text Available In this paper, an attempt has been made to develop an algorithm which estimates the similarity for XML Schemas using multiple similarity measures. For performing the task, the XML Schema element information has been represented in the form of string and four different similarity measure approaches have been employed. To further improve the similarity measure, an overall similarity measure has also been calculated. The approach used in this paper is a distinguished one, as it calculates the similarity between two XML schemas using four approaches and gives an integrated values for the similarity measure. Keywords-componen

  10. Sunlight assisted synthesis of silver nanoparticles in zeolite matrix and study of its application on electrochemical detection of dopamine and uric acid in urine samples.

    Science.gov (United States)

    Meenakshi, S; Devi, S; Pandian, K; Devendiran, R; Selvaraj, M

    2016-12-01

    Sunlight assisted reduction of silver ions were accomplished for the synthesis of silver nanoparticles incorporated within the mesoporous silicate framework of zeolite Y. The zeolite-Y and AgNP/Zeo-Y were characterized by field emission scanning electron microscopy, transmission electron microscopy, N2 adsorption-desorption BET isotherm and X-ray diffraction techniques. The incorporation of silver nanoparticles within the porous framework was further confirmed by cyclic voltammetry and electrochemical impedance spectroscopy. An enhanced electrocatalytic oxidation of biologically important molecules like dopamine and uric acid using AgNP/Zeo-Y modified glassy carbon electrode has been developed. A simultaneous oxidation of DA and UA peaks were obtained at +0.31V and +0.43V (vs. Ag/AgCl) using AgNP/Zeo-Y/GCE under the optimum experimental condition. A well-resolved peak potential window (~120mV) for the oxidation of both DA and UA were observed at AgNP/Zeo-Y/GCE system. The calibration curves for DA and UA were obtained within the dynamic linear range of 0.02×10(-6) to 0.18×10(-6)M (R(2)=0.9899) and 0.05×10(-6) to 0.7×10(-6)M (R(2)=0.9996) and the detection limits were found to be 1.6×10(-8)M and 2.51×10(-8)M by using differential pulse voltammetry (DPV) method. The proposed method was successfully applied for the determination of both DA and UA in human urine samples with a related standard deviation was <3%, and n=5 using the standard addition method. PMID:27612692

  11. MALDI Matrix Research for Biopolymers

    Science.gov (United States)

    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

  12. A mouse 3T6 fibroblast cell culture model for the study of normal and protein-engineered collagen synthesis and deposition into the extracellular matrix.

    Science.gov (United States)

    Lamandé, S R; Bateman, J F

    1993-07-01

    Mouse 3T6 fibroblasts deposited an organized collagenous extracellular matrix during long-term culture in the presence of ascorbic acid. The matrix produced by the cells had a similar distribution of collagen types as the mouse dermal matrix, comprising predominantly type I with smaller amounts of types III and V collagens. By day 8 of culture more than 70% of the collagen in the 3T6 matrix was involved in covalent crosslinkages and required pepsin digestion for extraction. Incorporation of NaB3H4 into reducible crosslinks and aldehydes directly demonstrated the involvement of the alpha 1 (I)CB6 and alpha 2(I)CB3.5 in crosslinks. The pattern of reducible crosslinks in the in vitro 3T6 matrix was similar to that in mouse skin suggesting a comparable fibril organization. Processing of procollagen to collagen occurred efficiently throughout the culture period and the rate of collagen production was unaltered during 15 days of culture, indicating that the development of a collagenous matrix does not directly play a role in procollagen processing or biosynthetic regulation. The existence of a preformed matrix did however, increase the efficiency with which newly synthesised collagen was incorporated into the pericellular matrix. At day 0, when there was no measurable matrix present, 29% of the collagen synthesised was deposited, while by day 15, 88% of the collagen was laid down in the matrix. The development of this 3T6 culture system, where collagen is efficiently incorporated into an organized extracellular matrix, will facilitate detailed studies on matrix organization and regulation and provide a system in which protein-engineered mutant collagens can be expressed to determine their effects on the production of a functional extracellular matrix. PMID:8412990

  13. Multivariate Time Series Similarity Searching

    OpenAIRE

    Jimin Wang; Yuelong Zhu; Shijin Li; Dingsheng Wan; Pengcheng Zhang

    2014-01-01

    Multivariate time series (MTS) datasets are very common in various financial, multimedia, and hydrological fields. In this paper, a dimension-combination method is proposed to search similar sequences for MTS. Firstly, the similarity of single-dimension series is calculated; then the overall similarity of the MTS is obtained by synthesizing each of the single-dimension similarity based on weighted BORDA voting method. The dimension-combination method could use the existing similarity searchin...

  14. Web Search Results Summarization Using Similarity Assessment

    Directory of Open Access Journals (Sweden)

    Sawant V.V.

    2014-06-01

    Full Text Available Now day’s internet has become part of our life, the WWW is most important service of internet because it allows presenting information such as document, imaging etc. The WWW grows rapidly and caters to a diversified levels and categories of users. For user specified results web search results are extracted. Millions of information pouring online, users has no time to surf the contents completely .Moreover the information available is repeated or duplicated in nature. This issue has created the necessity to restructure the search results that could yield results summarized. The proposed approach comprises of different feature extraction of web pages. Web page visual similarity assessment has been employed to address the problems in different fields including phishing, web archiving, web search engine etc. In this approach, initially by enters user query the number of search results get stored. The Earth Mover's Distance is used to assessment of web page visual similarity, in this technique take the web page as a low resolution image, create signature of that web page image with color and co-ordinate features .Calculate the distance between web pages by applying EMD method. Compute the Layout Similarity value by using tag comparison algorithm and template comparison algorithm. Textual similarity is computed by using cosine similarity, and hyperlink analysis is performed to compute outward links. The final similarity value is calculated by fusion of layout, text, hyperlink and EMD value. Once the similarity matrix is found clustering is employed with the help of connected component. Finally group of similar web pages i.e. summarized results get displayed to user. Experiment conducted to demonstrate the effectiveness of four methods to generate summarized result on different web pages and user queries also.

  15. New approach for distinguishing the similarity of links

    Institute of Scientific and Technical Information of China (English)

    Jianyun XIANG; Maozhong GE; Zhiping WANG

    2008-01-01

    Based on the problem of distinguishing the similarity of links in the regenerative innovation design of a kinematic chain, a new approach using the standard power matrix of the adjacent matrix is presented in this paper. The implementation of the approach is illustrated with an example. This method solves the technically baffling problem in mechanism type synthesis and reduced redundant design scheme, and raises the reliability and the efficiency of the regenerative innova-tion design of the kinematic chain.

  16. Calculating the GONG Leakage Matrix

    Science.gov (United States)

    Hill, F.; Howe, R.

    Since spherical harmonics do not form a complete orthonormal basis set over a portion of a sphere, helioseismic spectra computed for a specific target mode with degree ellt and azimuthal degree mt also contain modes with nearby ell'' and m''. These spatial leaks greatly increase the complexity of the observed spectrum, complicating the spectral fitting and degrading the resulting mode parameter estimates. This is particularly true where the target mode and the leaks have similar frequencies. Some strategies for fitting helioseismic spectra explicitly include the leakage matrix which estimates the relative strength of a mode (ell'' and m'') in the spectrum at (ellt,mt). Since the fitting methods assume that the matrix is correct and apply it as a constraint, an inaccurate matrix introduces systematic errors in the estimated mode parameters. It is thus important to have as accurate a matrix as possible. Here we report on the calculation of the leakage matrix for the GONG observations. The matrix elements are essentially the integrals (over the observed portion of the solar surface) of the crossproducts of the two spherical harmonics. However, several effects have been included to increase the accuracy of the matrix. These include the projection factor of the observable (velocity, intensity, modulation), the spatial apodization applied to the data, the finite rectangular pixel dimensions of the observations, and possible errors in the estimated image geometry. Other factors to be incorporated are the observed MTF, the merging of the GONG images, and the horizontal components of the oscillatory velocity field. We will compare the latest calculation with the observed spectrum and assess the relative importance of the input factors. We will also compare the leakage matrices for velocity and intensity to estimate their contribution to the large apparent differences in the helioseismic spectra obtained from these observables.

  17. Characterization of organic matrix extracted from fresh water pearls

    International Nuclear Information System (INIS)

    Aragonite pearl and vaterite pearl from cultured Hyriopsis cumingii in Zhuji (Zhejiang province, China) were chosen for the study. The matrix proteins were extracted using water and weak acid, and classified as water soluble matrix (WSM), acid soluble matrix (ASM) and acid insoluble matrix (AIM). The proteins from both pearls were characterized by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), X-ray diffraction (XRD) and Fourier transformation infrared spectra (FTIR). The results showed that, AIM of aragonite pearl and vaterite pearl had an ordered structure of α-helix. ASM conformations of these two pearls were different from each other. WSM differed the most between these two pearls. - Research Highlights: → We use a specific method for extracting matrix proteins from aragonite pearl and vaterite pearl respectively. → The matrix proteins are extracted by water and weak acid, and classified as water soluble matrix (WSM), acid soluble matrix (ASM) and acid insoluble matrix (AIM). → AIM of aragonite pearl and vaterite pearl have an ordered structure. ASM conformations of the two pearls are different from each other. WSM differ the most between these two pearls.

  18. Acoustic Similarity and Dichotic Listening.

    Science.gov (United States)

    Benson, Peter

    1978-01-01

    An experiment tests conjectures that right ear advantage (REA) has an auditory origin in competition or interference between acoustically similar stimuli and that feature-sharing effect (FSE) has its origin in assignment of features of phonetically similar stimuli. No effect on the REA for acoustic similarity, and a clear effect of acoustic…

  19. Functional Similarity and Interpersonal Attraction.

    Science.gov (United States)

    Neimeyer, Greg J.; Neimeyer, Robert A.

    1981-01-01

    Students participated in dyadic disclosure exercises over a five-week period. Results indicated members of high functional similarity dyads evidenced greater attraction to one another than did members of low functional similarity dyads. "Friendship" pairs of male undergraduates displayed greater functional similarity than did "nominal" pairs from…

  20. The Matrix Cookbook

    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....

  1. Similitudes, diferencias y agonismos en los efectos pleiotrópicos de las estatinas y los ácidos grasos omega-3 Similarities, differences and agonisms of pleiotropic effects of statins and omega-3 fatty acids

    Directory of Open Access Journals (Sweden)

    M.ª E. Villalobos

    2010-12-01

    grupos de compuestos en el tratamiento de CVD y se concluye que pueden obtenerse claros beneficios.This paper compares the pleiotropic effects of statins and omega-3 fatty acids (n-3 PUFA in treating and preventing cardiovascular disease (CVD and deals with the possible interactions of those compounds. Statins represent one of the most important discoveries to have been made in the field of cardiovascular medicine in recent decades. Their beneficial cardiovascular effects, which have reduced the number of fatal events in patients with atherosclerosis, encompass more than their ability to lower cholesterol levels. The pleiotropic effects of statins involve their anti-inflammatory and antiplatelet properties and their ability to normalize endothelial function. In addition, these drugs may display antiarrhythmic activity, improve insulin sensitivity and counteract hypertension and obesity. The low rate of coronary disease documented in Eskimos corroborates the cardioprotective effects of the n-3 PUFA eicosapentaenoic (EPA and docosahexaenoic acids beyond their hypolipemic effects. The reduction of CVD-related deaths attributable to the action of α-linolenic fatty acid appears to be related to its strong antiarrhythmic properties. In addition, as a precursor of EPA and this last fatty acid of thromboxane A3, prostacyclin I3, serie-3 prostaglandines and serie 5-leukotrines and inhibitor/modulator of thromboxane A2, prostacyclin I2, serie-2 prostaglandines and serie 4-leukotrienes formation, the α-linolenic acid may reduce inflammation and thrombogenesis. As results of some studies suggest that the combined use of statins and n-3 PUFA improves cardiovascular protection and reduces the CVD-related mortality rate; the paper also reviews the possible synergism between both groups of compounds on CVD treatment and concludes that clear benefits may be obtained.

  2. Matrix Order Differintegration

    OpenAIRE

    Naber, Mark

    2003-01-01

    The Riemann-Liouville formula for fractional derivatives and integrals (differintegration) is used to derive formulae for matrix order derivatives and integrals. That is, the parameter for integration and differentiation is allowed to assume matrix values. It is found that the computation of derivatives and integrals to matrix order is well defined for any square matrix over the complex numbers. Some properties are worked out for special classes of matrices. It is hoped that this new formalis...

  3. Matrix Tile Analysis

    OpenAIRE

    Givoni, Inmar; Cheung, Vincent; Frey, Brendan J.

    2012-01-01

    Many tasks require finding groups of elements in a matrix of numbers, symbols or class likelihoods. One approach is to use efficient bi- or tri-linear factorization techniques including PCA, ICA, sparse matrix factorization and plaid analysis. These techniques are not appropriate when addition and multiplication of matrix elements are not sensibly defined. More directly, methods like bi-clustering can be used to classify matrix elements, but these methods make the overly-restrictive assumptio...

  4. Matrix with Prescribed Eigenvectors

    Science.gov (United States)

    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…

  5. Fatigue testing and damage development in continuous fiber reinforced metal matrix composites

    Science.gov (United States)

    Johnson, W. S.

    1989-01-01

    A general overview of the fatigue behavior of metal matrix composites (MMC) is presented. The first objective is to present experimental procedures and techniques for conducting a meaningful fatigue test to detect and quantify fatigue damage in MMC. These techniques include interpretation of stress-strain responses, acid etching of the matrix, edge replicas of the specimen under load, radiography, and micrographs of the failure surfaces. In addition, the paper will show how stiffness loss in continuous fiber reinforced metal matrix composites can be a useful parameter for detecting fatigue damage initiation and accumulation. Second, numerous examples of how fatigue damage can initiate and grow in various MMC are given. Depending on the relative fatigue behavior of the fiber and matrix, and the interface properties, the failure modes of MMC can be grouped into four categories: (1) matrix dominated, (2) fiber dominated, (3) self-similar damage growth, and (4) fiber/matrix interfacial failures. These four types of damage will be discussed and illustrated by examples with the emphasis on the fatigue of unnotched laminates.

  6. EMRE Is a Matrix Ca2+ Sensor that Governs Gatekeeping of the Mitochondrial Ca2+ Uniporter

    Directory of Open Access Journals (Sweden)

    Horia Vais

    2016-01-01

    Full Text Available The mitochondrial uniporter (MCU is an ion channel that mediates Ca2+ uptake into the matrix to regulate metabolism, cell death, and cytoplasmic Ca2+ signaling. Matrix Ca2+ concentration is similar to that in cytoplasm, despite an enormous driving force for entry, but the mechanisms that prevent mitochondrial Ca2+ overload are unclear. Here, we show that MCU channel activity is governed by matrix Ca2+ concentration through EMRE. Deletion or charge neutralization of its matrix-localized acidic C terminus abolishes matrix Ca2+ inhibition of MCU Ca2+ currents, resulting in MCU channel activation, enhanced mitochondrial Ca2+ uptake, and constitutively elevated matrix Ca2+ concentration. EMRE-dependent regulation of MCU channel activity requires intermembrane space-localized MICU1, MICU2, and cytoplasmic Ca2+. Thus, mitochondria are protected from Ca2+ depletion and Ca2+ overload by a unique molecular complex that involves Ca2+ sensors on both sides of the inner mitochondrial membrane, coupled through EMRE.

  7. Alteration of the interconversion of pyruvate and malate in the plastid or cytosol of ripening tomato fruit invokes diverse consequences on sugar but similar effects on cellular organic acid, metabolism, and transitory starch accumulation.

    Science.gov (United States)

    Osorio, Sonia; Vallarino, José G; Szecowka, Marek; Ufaz, Shai; Tzin, Vered; Angelovici, Ruthie; Galili, Gad; Fernie, Alisdair R

    2013-02-01

    The aim of this work was to investigate the effect of decreased cytosolic phosphoenolpyruvate carboxykinase (PEPCK) and plastidic NADP-dependent malic enzyme (ME) on tomato (Solanum lycopersicum) ripening. Transgenic tomato plants with strongly reduced levels of PEPCK and plastidic NADP-ME were generated by RNA interference gene silencing under the control of a ripening-specific E8 promoter. While these genetic modifications had relatively little effect on the total fruit yield and size, they had strong effects on fruit metabolism. Both transformants were characterized by lower levels of starch at breaker stage. Analysis of the activation state of ADP-glucose pyrophosphorylase correlated with the decrease of starch in both transformants, which suggests that it is due to an altered cellular redox status. Moreover, metabolic profiling and feeding experiments involving positionally labeled glucoses of fruits lacking in plastidic NADP-ME and cytosolic PEPCK activities revealed differential changes in overall respiration rates and tricarboxylic acid (TCA) cycle flux. Inactivation of cytosolic PEPCK affected the respiration rate, which suggests that an excess of oxaloacetate is converted to aspartate and reintroduced in the TCA cycle via 2-oxoglutarate/glutamate. On the other hand, the plastidic NADP-ME antisense lines were characterized by no changes in respiration rates and TCA cycle flux, which together with increases of pyruvate kinase and phosphoenolpyruvate carboxylase activities indicate that pyruvate is supplied through these enzymes to the TCA cycle. These results are discussed in the context of current models of the importance of malate during tomato fruit ripening.

  8. Investigation of redox activities of soil humic acids using 3D excitation emission matrix fluorescence spectroscopy%基于三维荧光光谱特征研究土壤腐殖质氧化还原特性

    Institute of Scientific and Technical Information of China (English)

    姜杰; 李黎; 孙国新

    2012-01-01

    Humic substances serve as electron shuttles in the soil environment. They not only stimulate the element migration, but also accelerate containment degradation and environment remediation. In this study, a standard humic acid and two extracted humic acids from soil samples were reduced by H2, and three-dimensional excitation emission matrix fluorescence spectroscopy (3DEEM) was employed to characterize these humic acids. The results of 3DEEMs revealed the differences between native and reduced humic acids. Fluorescence peak intensity of humic acids in the reduced state was lower than those in the natural state, which can be explained by the changes of chemical structures of humic acids, such as the loss of π-π bonds. As a model compound of quinone groups in humic acids, benzoquinone reduction and 3DEEM analysis were carried out under the same conditions. It was observed that there was a decrease of fluorescence with benzoquinone reduction. Potassium ferricyanide method was used to measure the reducing capacity of native extracted humic acids, which was found to be 0. 998 and 0. 465 meq. g-1 C for Yingtan and Taoyuan soils, respectively. Electron accepting capacities of humic acids were 3. 384 and 1.187 meq-g 1 C for Yingtan and Taoyuan soils, respectively. Determination of electron accepting capacities, quantification of redox-active functional groups and prediction of redox reaction processes in soil are all important applications of 3 DEEM in the investigation of humic acid redox-activities.%以国际腐殖质协会腐殖酸和实验室提纯腐殖酸为研究对象,发现被H2还原前后腐殖酸的三维荧光光谱明显不同,但有共同的变化趋势:还原态腐殖酸的三维荧光光谱图的波峰荧光强度均明显低于还原前,说明腐殖酸还原过程有类似π-π化学键断开的结构变化.对苯醌是腐殖酸氧化还原醌基官能团的代表化合物,将其还原前后与腐殖酸还原前后的荧光光

  9. Bosonic Matrix Theory and Matrix Dbranes

    CERN Document Server

    Chaudhuri, S

    2002-01-01

    We develop new tools for an in-depth investigation of our recent proposal for Matrix Theory. We construct the anomaly-free and finite planar continuum limit of the ground state with SO(2^{13}) symmetry matching with the tadpole and tachyon free IR stable high temperature ground state of the open and closed bosonic string. The correspondence between large N limits and spacetime effective actions is demonstrated more generally for an arbitrary D25brane ground state which might include brane-antibrane pairs or NS-branes and which need not have an action formulation. Closure of the finite N matrix Lorentz algebra nevertheless requires that such a ground state is simultaneously charged under all even rank antisymmetric matrix potentials. Additional invariance under the gauge symmetry mediated by the one-form matrix potential requires a ground state charged under the full spectrum of antisymmetric (p+1)-form matrix potentials with p taking any integer value less than 26. Matrix Dbrane democracy has a beautiful larg...

  10. Learning Multi-modal Similarity

    CERN Document Server

    McFee, Brian

    2010-01-01

    In many applications involving multi-media data, the definition of similarity between items is integral to several key tasks, e.g., nearest-neighbor retrieval, classification, and recommendation. Data in such regimes typically exhibits multiple modalities, such as acoustic and visual content of video. Integrating such heterogeneous data to form a holistic similarity space is therefore a key challenge to be overcome in many real-world applications. We present a novel multiple kernel learning technique for integrating heterogeneous data into a single, unified similarity space. Our algorithm learns an optimal ensemble of kernel transfor- mations which conform to measurements of human perceptual similarity, as expressed by relative comparisons. To cope with the ubiquitous problems of subjectivity and inconsistency in multi- media similarity, we develop graph-based techniques to filter similarity measurements, resulting in a simplified and robust training procedure.

  11. Roget's Thesaurus and Semantic Similarity

    OpenAIRE

    Jarmasz, Mario; Szpakowicz, Stan

    2012-01-01

    We have implemented a system that measures semantic similarity using a computerized 1987 Roget's Thesaurus, and evaluated it by performing a few typical tests. We compare the results of these tests with those produced by WordNet-based similarity measures. One of the benchmarks is Miller and Charles' list of 30 noun pairs to which human judges had assigned similarity measures. We correlate these measures with those computed by several NLP systems. The 30 pairs can be traced back to Rubenstein ...

  12. RECOGNITION OF STRUCTURE SIMILARITIES IN PROTEINS

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Protein fold structure is more conserved than its amino acid sequence and closely associated with biological function,so calculating the similarity of protein structures is a fundamental problem in structural biology and plays a key role in protein fold classification,fold function inference,and protein structure prediction.Large progress has been made in recent years in this field and many methods for considering structural similarity have been proposed,including methods for protein structure compar-ison,retrieval of protein structures from databases,and ligand binding site comparison.Most of those methods can be available on the World Wide Web,but evaluation of all the methods is still a hard problem.This paper summarizes some popular methods and latest methods for structure similarities,including structure alignment,protein structure retrieval,and ligand binding site alignment.

  13. SPIC: A novel similarity metric for comparing transcription factor binding site motifs based on information contents

    OpenAIRE

    Zhang, Shaoqiang; Zhou, Xiguo; Du, Chuanbin; Su, Zhengchang

    2013-01-01

    Background Discovering transcription factor binding sites (TFBS) is one of primary challenges to decipher complex gene regulatory networks encrypted in a genome. A set of short DNA sequences identified by a transcription factor (TF) is known as a motif, which can be expressed accurately in matrix form such as a position-specific scoring matrix (PSSM) and a position frequency matrix. Very frequently, we need to query a motif in a database of motifs by seeking its similar motifs, merge similar ...

  14. Fatigue damage criteria - Matrix, fibers and interfaces of continuous fiber reinforced metal matrix composites

    Science.gov (United States)

    Johnson, W. S.

    1988-01-01

    Continuous fiber reinforced metal matrix composites (MMC) are projected for use in high temperature, stiffness critical parts that will be subjected to cyclic loadings. Depending on the relative fatigue behavior of the fiber and matrix, and the interface properties, the failure modes of MMC can be grouped into four catagories: (1) matrix dominated, (2) fiber dominated, (3) self-similar damage growth, and (4) fiber/matrix interfacial failures. These four types of damage are discussed and illustrated by examples. The emphasis is on the fatigue of unnotched laminates.

  15. A toolbox for representational similarity analysis.

    Directory of Open Access Journals (Sweden)

    Hamed Nili

    2014-04-01

    Full Text Available Neuronal population codes are increasingly being investigated with multivariate pattern-information analyses. A key challenge is to use measured brain-activity patterns to test computational models of brain information processing. One approach to this problem is representational similarity analysis (RSA, which characterizes a representation in a brain or computational model by the distance matrix of the response patterns elicited by a set of stimuli. The representational distance matrix encapsulates what distinctions between stimuli are emphasized and what distinctions are de-emphasized in the representation. A model is tested by comparing the representational distance matrix it predicts to that of a measured brain region. RSA also enables us to compare representations between stages of processing within a given brain or model, between brain and behavioral data, and between individuals and species. Here, we introduce a Matlab toolbox for RSA. The toolbox supports an analysis approach that is simultaneously data- and hypothesis-driven. It is designed to help integrate a wide range of computational models into the analysis of multichannel brain-activity measurements as provided by modern functional imaging and neuronal recording techniques. Tools for visualization and inference enable the user to relate sets of models to sets of brain regions and to statistically test and compare the models using nonparametric inference methods. The toolbox supports searchlight-based RSA, to continuously map a measured brain volume in search of a neuronal population code with a specific geometry. Finally, we introduce the linear-discriminant t value as a measure of representational discriminability that bridges the gap between linear decoding analyses and RSA. In order to demonstrate the capabilities of the toolbox, we apply it to both simulated and real fMRI data. The key functions are equally applicable to other modalities of brain-activity measurement. The

  16. Multiscale characterization of chemical–mechanical interactions between polymer fibers and cementitious matrix

    Energy Technology Data Exchange (ETDEWEB)

    Hernández-Cruz, Daniel; Hargis, Craig W.; Bae, Sungchul; Itty, Pierre A.; Meral, Cagla; Dominowski, Jolee; Radler, Michael J.; Kilcoyne, David A.; Monteiro, Paulo J. M.

    2014-04-01

    Together with a series of mechanical tests, the interactions and potential bonding between polymeric fibers and cementitious materials were studied using scanning transmission X-ray microscopy (STXM) and microtomography (lCT). Experimental results showed that these techniques have great potential to characterize the polymer fiber-hydrated cement-paste matrix interface, as well as differentiating the chemistry of the two components of a bi-polymer (hybrid) fiber the polypropylene core and the ethylene acrylic acid copolymer sheath. Similarly, chemical interactions between the hybrid fiber and the cement hydration products were observed, indicating the chemical bonding between the sheath and the hardened cement paste matrix. Microtomography allowed visualization of the performance of the samples, and the distribution and orientation of the two types of fiber in mortar. Beam flexure tests confirmed improved tensile strength of mixes containing hybrid fibers, and expansion bar tests showed similar reductions in expansion for the polypropylene and hybrid fiber mortar bars.

  17. Dynamic similarity in erosional processes

    Science.gov (United States)

    Scheidegger, A.E.

    1963-01-01

    A study is made of the dynamic similarity conditions obtaining in a variety of erosional processes. The pertinent equations for each type of process are written in dimensionless form; the similarity conditions can then easily be deduced. The processes treated are: raindrop action, slope evolution and river erosion. ?? 1963 Istituto Geofisico Italiano.

  18. Comparison of peptide nucleic acid fluorescence in situ hybridization assays with culture-based matrix-assisted laser desorption/ionization-time of flight mass spectrometry for the identification of bacteria and yeasts from blood cultures and cerebrospinal fluid cultures.

    Science.gov (United States)

    Calderaro, A; Martinelli, M; Motta, F; Larini, S; Arcangeletti, M C; Medici, M C; Chezzi, C; De Conto, F

    2014-08-01

    Peptide nucleic acid fluorescence in situ hybridization (PNA FISH) is a molecular diagnostic tool for the rapid detection of pathogens directly from liquid media. The aim of this study was to prospectively evaluate PNA FISH assays in comparison with culture-based matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) identification, as a reference method, for both blood and cerebrospinal fluid (CSF) cultures, during a 1-year investigation. On the basis of the Gram stain microscopy results, four different PNA FISH commercially available assays were used ('Staphylococcus aureus/CNS', 'Enterococcus faecalis/OE', 'GNR Traffic Light' and 'Yeasts Traffic Light' PNA FISH assays, AdvanDx). The four PNA FISH assays were applied to 956 positive blood cultures (921 for bacteria and 35 for yeasts) and 11 CSF cultures. Among the 921 blood samples positive for bacteria, PNA FISH gave concordant results with MALDI-TOF MS in 908/921 (98.64%) samples, showing an agreement of 99.4% in the case of monomicrobial infections. As regards yeasts, the PNA FISH assay showed a 100% agreement with the result obtained by MALDI-TOF MS. When PNA FISH assays were tested on the 11 CSF cultures, the results agreed with the reference method in all cases (100%). PNA FISH assays provided species identification at least one work-day before the MALDI-TOF MS culture-based identification. PNA FISH assays showed an excellent efficacy in the prompt identification of main pathogens, yielding a significant reduction in reporting time and leading to more appropriate patient management and therapy in cases of sepsis and severe infections.

  19. Personalized recommendation with corrected similarity

    International Nuclear Information System (INIS)

    Personalized recommendation has attracted a surge of interdisciplinary research. Especially, similarity-based methods in applications of real recommendation systems have achieved great success. However, the computations of similarities are overestimated or underestimated, in particular because of the defective strategy of unidirectional similarity estimation. In this paper, we solve this drawback by leveraging mutual correction of forward and backward similarity estimations, and propose a new personalized recommendation index, i.e., corrected similarity based inference (CSI). Through extensive experiments on four benchmark datasets, the results show a greater improvement of CSI in comparison with these mainstream baselines. And a detailed analysis is presented to unveil and understand the origin of such difference between CSI and mainstream indices. (paper)

  20. Compressive Sequential Learning for Action Similarity Labeling.

    Science.gov (United States)

    Qin, Jie; Liu, Li; Zhang, Zhaoxiang; Wang, Yunhong; Shao, Ling

    2016-02-01

    Human action recognition in videos has been extensively studied in recent years due to its wide range of applications. Instead of classifying video sequences into a number of action categories, in this paper, we focus on a particular problem of action similarity labeling (ASLAN), which aims at verifying whether a pair of videos contain the same type of action or not. To address this challenge, a novel approach called compressive sequential learning (CSL) is proposed by leveraging the compressive sensing theory and sequential learning. We first project data points to a low-dimensional space by effectively exploring an important property in compressive sensing: the restricted isometry property. In particular, a very sparse measurement matrix is adopted to reduce the dimensionality efficiently. We then learn an ensemble classifier for measuring similarities between pairwise videos by iteratively minimizing its empirical risk with the AdaBoost strategy on the training set. Unlike conventional AdaBoost, the weak learner for each iteration is not explicitly defined and its parameters are learned through greedy optimization. Furthermore, an alternative of CSL named compressive sequential encoding is developed as an encoding technique and followed by a linear classifier to address the similarity-labeling problem. Our method has been systematically evaluated on four action data sets: ASLAN, KTH, HMDB51, and Hollywood2, and the results show the effectiveness and superiority of our method for ASLAN.

  1. Fast and secure similarity search in high dimensional space

    OpenAIRE

    Furon, Teddy; Jégou, Hervé; Amsaleg, Laurent; Mathon, Benjamin

    2013-01-01

    Similarity search in high dimensional space database is split into two worlds: i) fast, scalable, and approximate search algorithms which are not secure, and ii) search protocols based on secure computation which are not scalable. This paper presents a one-way privacy protocol that lies in between these two worlds. Approximate metrics for the cosine similarity allows speed. Elements of large random matrix theory provides security evidences if the size of the database is not too big with respe...

  2. Hybrid Textures of Neutrino Mass Matrix

    CERN Document Server

    Kaneko, S; Tanimoto, M; Kaneko, Satoru; Sawanaka, Hideyuki; Tanimoto, Morimitsu

    2005-01-01

    We present analyses of the sixty hybrid textures of neutrino mass matrix, which have an equality of matrix elements and one zero. These textures are possibly derived in the models with discrete flavor symmetry. Only six textures among sixty ones are excluded by the present experimental data. Since there are many textures which give similar predictions, the textures are classified based on the numerical results. The neutrinoless double beta decay is also examined in these textures. Our results suggest that there remain still rich structures of the neutrino mass matrix in the phenomenological point of view.

  3. Ranking and clustering of search results: Analysis of Similarity graph

    OpenAIRE

    Shevchuk, Ksenia Alexander

    2008-01-01

    Evaluate the clustering of the similarity matrix and confirm that it is high. Compare the ranking results of the eigenvector ranking and the Link Popularity ranking and confirm for the high clustered graph the correlation between those is larger than for the low clustered graph.

  4. Similarity of samples and trimming

    CERN Document Server

    Álvarez-Esteban, Pedro C; Cuesta-Albertos, Juan A; Matrán, Carlos; 10.3150/11-BEJ351

    2012-01-01

    We say that two probabilities are similar at level $\\alpha$ if they are contaminated versions (up to an $\\alpha$ fraction) of the same common probability. We show how this model is related to minimal distances between sets of trimmed probabilities. Empirical versions turn out to present an overfitting effect in the sense that trimming beyond the similarity level results in trimmed samples that are closer than expected to each other. We show how this can be combined with a bootstrap approach to assess similarity from two data samples.

  5. Parallelism in matrix computations

    CERN Document Server

    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...

  6. Melvin Matrix Models

    CERN Document Server

    Motl, L

    2001-01-01

    In this short note we construct the DLCQ description of the flux seven-branes in type IIA string theory and discuss its basic properties. The matrix model involves dipole fields. We explain the relation of this nonlocal matrix model to various orbifolds. We also give a spacetime interpretation of the Seiberg-Witten-like map, proposed in a different context first by Bergman and Ganor, that converts this matrix model to a local, highly nonlinear theory.

  7. Self-similar aftershock rates

    CERN Document Server

    Davidsen, Jörn

    2016-01-01

    In many important systems exhibiting crackling noise --- intermittent avalanche-like relaxation response with power-law and, thus, self-similar distributed event sizes --- the "laws" for the rate of activity after large events are not consistent with the overall self-similar behavior expected on theoretical grounds. This is in particular true for the case of seismicity and a satisfying solution to this paradox has remained outstanding. Here, we propose a generalized description of the aftershock rates which is both self-similar and consistent with all other known self-similar features. Comparing our theoretical predictions with high resolution earthquake data from Southern California we find excellent agreement, providing in particular clear evidence for a unified description of aftershocks and foreshocks. This may offer an improved way of time-dependent seismic hazard assessment and earthquake forecasting.

  8. Self-similar aftershock rates

    Science.gov (United States)

    Davidsen, Jörn; Baiesi, Marco

    2016-08-01

    In many important systems exhibiting crackling noise—an intermittent avalanchelike relaxation response with power-law and, thus, self-similar distributed event sizes—the "laws" for the rate of activity after large events are not consistent with the overall self-similar behavior expected on theoretical grounds. This is particularly true for the case of seismicity, and a satisfying solution to this paradox has remained outstanding. Here, we propose a generalized description of the aftershock rates which is both self-similar and consistent with all other known self-similar features. Comparing our theoretical predictions with high-resolution earthquake data from Southern California we find excellent agreement, providing particularly clear evidence for a unified description of aftershocks and foreshocks. This may offer an improved framework for time-dependent seismic hazard assessment and earthquake forecasting.

  9. SELF-SIMILAR TRAFFIC GENERATOR

    OpenAIRE

    Linawati Linawati; I Made Suartika

    2009-01-01

    Network traffic generator can be produced using OPNET. OPNET generates the traffic as explicit traffic or background traffic. This paper demonstrates generating traffic in OPNET 7.0 as background traffic. The traffi generator that was simulated is self-similar traffic with different Hurst parameter. The simulation results proved that OPNET with background traffic function can be as a qualified self-similar traffic generator. These results can help in investigating and analysing network perfor...

  10. Similarity measures for protein ensembles

    DEFF Research Database (Denmark)

    Lindorff-Larsen, Kresten; Ferkinghoff-Borg, Jesper

    2009-01-01

    Analyses of similarities and changes in protein conformation can provide important information regarding protein function and evolution. Many scores, including the commonly used root mean square deviation, have therefore been developed to quantify the similarities of different protein conformations...... a synthetic example from molecular dynamics simulations. We then apply the algorithms to revisit the problem of ensemble averaging during structure determination of proteins, and find that an ensemble refinement method is able to recover the correct distribution of conformations better than standard single...

  11. Self-Similar Isentropic Implosions

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, M.; Amable, L.

    1980-07-01

    The self-similar compression of an isentropic spherical gas pellet Is analyzed for large values of the ratio of the final to initial densities. An asymptotic analysis provides the solution corresponding to a prescribed value of the final density when it is high. In addition an approximate solution is given when the specific heat ratio is not constant. The time evolution of the pressure on the outer surface leading to the self-similar solutions, is calculated for large density ratios. (Author)

  12. Molecular similarity of MDR inhibitors

    OpenAIRE

    Simon Gibbons; Mire Zloh

    2004-01-01

    Abstract: The molecular similarity of multidrug resistance (MDR) inhibitors was evaluated using the point centred atom charge approach in an attempt to find some common features of structurally unrelated inhibitors. A series of inhibitors of bacterial MDR were studied and there is a high similarity between these in terms of their shape, presence and orientation of aromatic ring moieties. A comparison of the lipophilic properties of these molecules has also been conducted suggesting that this ...

  13. Mixed matrix membrane development.

    Science.gov (United States)

    Kulprathipanja, Santi

    2003-03-01

    Two types of mixed matrix membranes were developed by UOP in the late 1980s. The first type includes adsorbent polymers, such as silicalite-cellulose acetate (CA), NaX-CA, and AgX-CA mixed matrix membranes. The silicalite-CA has a CO(2)/H(2) selectivity of 5.15 +/- 2.2. In contrast, the CA membrane has a CO(2)/H(2) selectivity of 0.77 +/- 0.06. The second type of mixed matrix membrane is PEG-silicone rubber. The PEG-silicone rubber mixed matrix membrane has high selectivity for polar gases, such as SO(2), NH(3), and H(2)S.

  14. Modular Matrix Models

    OpenAIRE

    He, Y.; Jejjala, V.

    2003-01-01

    Inspired by a formal resemblance of certain q-expansions of modular forms and the master field formalism of matrix models in terms of Cuntz operators, we construct a Hermitian one-matrix model, which we dub the ``modular matrix model.'' Together with an N=1 gauge theory and a special Calabi-Yau geometry, we find a modular matrix model that naturally encodes the Klein elliptic j-invariant, and hence, by Moonshine, the irreducible representations of the Fischer-Griess Monster group.

  15. Representation is representation of similarities.

    Science.gov (United States)

    Edelman, S

    1998-08-01

    Advanced perceptual systems are faced with the problem of securing a principled (ideally, veridical) relationship between the world and its internal representation. I propose a unified approach to visual representation, addressing the need for superordinate and basic-level categorization and for the identification of specific instances of familiar categories. According to the proposed theory, a shape is represented internally by the responses of a small number of tuned modules, each broadly selective for some reference shape, whose similarity to the stimulus it measures. This amounts to embedding the stimulus in a low-dimensional proximal shape space spanned by the outputs of the active modules. This shape space supports representations of distal shape similarities that are veridical as Shepard's (1968) second-order isomorphisms (i.e., correspondence between distal and proximal similarities among shapes, rather than between distal shapes and their proximal representations). Representation in terms of similarities to reference shapes supports processing (e.g., discrimination) of shapes that are radically different from the reference ones, without the need for the computationally problematic decomposition into parts required by other theories. Furthermore, a general expression for similarity between two stimuli, based on comparisons to reference shapes, can be used to derive models of perceived similarity ranging from continuous, symmetric, and hierarchical ones, as in multidimensional scaling (Shepard 1980), to discrete and nonhierarchical ones, as in the general contrast models (Shepard & Arabie 1979; Tversky 1977). PMID:10097019

  16. Novel entries in a fungal biofilm matrix encyclopedia.

    Science.gov (United States)

    Zarnowski, Robert; Westler, William M; Lacmbouh, Ghislain Ade; Marita, Jane M; Bothe, Jameson R; Bernhardt, Jörg; Lounes-Hadj Sahraoui, Anissa; Fontaine, Joël; Sanchez, Hiram; Hatfield, Ronald D; Ntambi, James M; Nett, Jeniel E; Mitchell, Aaron P; Andes, David R

    2014-08-05

    Virulence of Candida is linked with its ability to form biofilms. Once established, biofilm infections are nearly impossible to eradicate. Biofilm cells live immersed in a self-produced matrix, a blend of extracellular biopolymers, many of which are uncharacterized. In this study, we provide a comprehensive analysis of the matrix manufactured by Candida albicans both in vitro and in a clinical niche animal model. We further explore the function of matrix components, including the impact on drug resistance. We uncovered components from each of the macromolecular classes (55% protein, 25% carbohydrate, 15% lipid, and 5% nucleic acid) in the C. albicans biofilm matrix. Three individual polysaccharides were identified and were suggested to interact physically. Surprisingly, a previously identified polysaccharide of functional importance, β-1,3-glucan, comprised only a small portion of the total matrix carbohydrate. Newly described, more abundant polysaccharides included α-1,2 branched α-1,6-mannans (87%) associated with unbranched β-1,6-glucans (13%) in an apparent mannan-glucan complex (MGCx). Functional matrix proteomic analysis revealed 458 distinct activities. The matrix lipids consisted of neutral glycerolipids (89.1%), polar glycerolipids (10.4%), and sphingolipids (0.5%). Examination of matrix nucleic acid identified DNA, primarily noncoding sequences. Several of the in vitro matrix components, including proteins and each of the polysaccharides, were also present in the matrix of a clinically relevant in vivo biofilm. Nuclear magnetic resonance (NMR) analysis demonstrated interaction of aggregate matrix with the antifungal fluconazole, consistent with a role in drug impedance and contribution of multiple matrix components. Importance: This report is the first to decipher the complex and unique macromolecular composition of the Candida biofilm matrix, demonstrate the clinical relevance of matrix components, and show that multiple matrix components are needed

  17. Experimental observations of a nuclear matrix.

    Science.gov (United States)

    Nickerson, J

    2001-02-01

    Nuclei are intricately structured, and nuclear metabolism has an elaborate spatial organization. The architecture of the nucleus includes two overlapping and nucleic-acid-containing structures - chromatin and a nuclear matrix. The nuclear matrix is observed by microscopy in live, fixed and extracted cells. Its ultrastructure and composition show it to be, in large part, the ribonucleoprotein (RNP) network first seen in unfractionated cells more than 30 years ago. At that time, the discovery of this RNP structure explained surprising observations that RNA, packaged in proteins, is attached to an intranuclear, non-chromatin structure. Periodic and specific attachments of chromatin fibers to the nuclear matrix create the chromatin loop domains that can be directly observed by microscopy or inferred from biochemical experiments. The ultrastructure of the nuclear matrix is well characterized and consists of a nuclear lamina and an internal nuclear network of subassemblies linked together by highly structured fibers. These complex fibers are built on an underlying scaffolding of branched 10-nm filaments that connect to the nuclear lamina. The structural proteins of the nuclear lamina have been well characterized, but the structural biochemistry of the internal nuclear matrix has received less attention. Many internal matrix proteins have been identified, but far less is known about how these proteins assemble to make the fibers, filaments and other assemblies of the internal nuclear matrix. Correcting this imbalance will require the combined application of biochemistry and electron microscopy. The central problem in trying to define nuclear matrix structure is to identify the proteins that assemble into the 10-nm filaments upon which the interior architecture of the nucleus is constructed. Only by achieving a biochemical characterization of the nuclear matrix will we advance beyond simple microscopic observations of structure to a better understanding of nuclear matrix

  18. Study of ionization process of matrix molecules in matrix-assisted laser desorption ionization

    International Nuclear Information System (INIS)

    Highlights: ► Proton transfer and adduction reaction of matrix in MALDI were studied. ► Hydroxyl group forming intramolecular hydrogen bond was related to the ionization. ► Intramolecular proton transfer in the electronic excited state was the initial step. ► Non-volatile analytes stabilized protonated matrix in the ground state. ► A possible mechanism, “analyte support mechanism”, has been proposed. - Abstract: Proton transfer and adduction reaction of matrix molecules in matrix-assisted laser desorption ionization were studied. By using 2,4,6-trihydroxyacetophenone (THAP), 2,5-dihydroxybenzoic acid (DHBA), and their related compounds in which the position of a hydroxyl group is different, it was clarified that a hydroxyl group forming an intramolecular hydrogen bond is related to the ionization of matrix molecules. Intramolecular proton transfer in the electronic excited state of the matrix and subsequent proton adduction from a surrounding solvent to the charge-separated matrix are the initial steps for the ionization of matrix molecules. Nanosecond pump–probe NIR–UV mass spectrometry confirmed that the existence of analyte molecules having large dipole moment in their structures is necessary for the stabilization of [matrix + H]+ in the electronic ground state

  19. Study of matrix effects produced by inorganic species in inductively coupled plasma atomic emission spectrometry with several spray chambers

    International Nuclear Information System (INIS)

    In the present work, the influence of the spray chamber design on the matrix effects was investigated in Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). The study was carried out in terms of aerosol drop size distribution and emission signal. Solutions of two inorganic acids and salts were employed to characterize the extent of the matrix effects throughout this work. Several spray chambers. a double-pass (Scott - type), a conventional cyclonic, and two low-volume cyclonic - type spray chambers (i.e., Cinnabar, and Genie) were used in order to evaluate the matrix effects produced by nitric and sulphuric acid solutions. A glass concentric pneumatic micro nebulizer (Atom Mist) was used in conjunction with all four chambers. When nitric or sulphuric acid solutions were nebulized, the double pass spray chamber registered noticeable changes in the drop size distribution. The low-volume spray chambers, in turn, afforded changes in the aerosol drop size distributions similar to the conventional cyclonic one. The matrix effects on the signal were reduced with all three cyclonic spray chambers with respect to the double pass one. Concerning the effect of inorganic salts, the results obtained with a High Efficiency Nebulizer (HEN) coupled to a double pass spray chamber and to a cyclonic type one revealed several issues: (i) the matrix effects were more severe at low liquid and gas flow rates; (ii) as for inorganic acids, the use of a cyclonic spray chamber led to a mitigation of the matrix effects with respect to a double pass spray chamber. (author)

  20. [Modern polymers in matrix tablets technology].

    Science.gov (United States)

    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. PMID:25739125

  1. [Modern polymers in matrix tablets technology].

    Science.gov (United States)

    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.

  2. Matrix metalloproteinases and epileptogenesis.

    Science.gov (United States)

    Ikonomidou, Chrysanthy

    2014-12-01

    Matrix metalloproteinases are vital drivers of synaptic remodeling in health and disease. It is suggested that at early stages of epileptogenesis, inhibition of matrix metalloproteinases may help ameliorate cell death, aberrant network rewiring, and neuroinflammation and prevent development of epilepsy. PMID:26567100

  3. Similarity measures for face recognition

    CERN Document Server

    Vezzetti, Enrico

    2015-01-01

    Face recognition has several applications, including security, such as (authentication and identification of device users and criminal suspects), and in medicine (corrective surgery and diagnosis). Facial recognition programs rely on algorithms that can compare and compute the similarity between two sets of images. This eBook explains some of the similarity measures used in facial recognition systems in a single volume. Readers will learn about various measures including Minkowski distances, Mahalanobis distances, Hansdorff distances, cosine-based distances, among other methods. The book also summarizes errors that may occur in face recognition methods. Computer scientists "facing face" and looking to select and test different methods of computing similarities will benefit from this book. The book is also useful tool for students undertaking computer vision courses.

  4. Involvement of extracellular matrix constituents in breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Lochter, Andre; Bissell, Mina J

    1995-06-01

    It has recently been established that the extracellular matrix is required for normal functional differentiation of mammary epithelia not only in culture, but also in vivo. The mechanisms by which extracellular matrix affects differentiation, as well as the nature of extracellular matrix constituents which have major impacts on mammary gland function, have only now begun to be dissected. The intricate variety of extracellular matrix-mediated events and the remarkable degree of plasticity of extracellular matrix structure and composition at virtually all times during ontogeny, make such studies difficult. Similarly, during carcinogenesis, the extracellular matrix undergoes gross alterations, the consequences of which are not yet precisely understood. Nevertheless, an increasing amount of data suggests that the extracellular matrix and extracellular matrix-receptors might participate in the control of most, if not all, of the successive stages of breast tumors, from appearance to progression and metastasis.

  5. An Algebraic Relation between Consimilarity and Similarity of Quaternion Matrices and Applications

    Directory of Open Access Journals (Sweden)

    Tongsong Jiang

    2014-01-01

    Full Text Available This paper, by means of complex representation of a quaternion matrix, discusses the consimilarity of quaternion matrices, and obtains a relation between consimilarity and similarity of quaternion matrices. It sets up an algebraic bridge between consimilarity and similarity, and turns the theory of consimilarity of quaternion matrices into that of ordinary similarity of complex matrices. This paper also gives algebraic methods for finding coneigenvalues and coneigenvectors of quaternion matrices by means of complex representation of a quaternion matrix.

  6. Fuzzy vulnerability matrix

    International Nuclear Information System (INIS)

    The so-called vulnerability matrix is used in the evaluation part of the probabilistic safety assessment for a nuclear power plant, during the containment event trees calculations. This matrix is established from what is knows as Numerical Categories for Engineering Judgement. This matrix is usually established with numerical values obtained with traditional arithmetic using the set theory. The representation of this matrix with fuzzy numbers is much more adequate, due to the fact that the Numerical Categories for Engineering Judgement are better represented with linguistic variables, such as 'highly probable', 'probable', 'impossible', etc. In the present paper a methodology to obtain a Fuzzy Vulnerability Matrix is presented, starting from the recommendations on the Numerical Categories for Engineering Judgement. (author)

  7. Double coincidence matrix

    International Nuclear Information System (INIS)

    To increase the accuracy of discrimination of true coincidences against the background of accidental ones, circuit has been developed which operates on the principle of dynamic equalization of resolution times of two coincidence circuits. The flowsheet of a 4x6 double-coincidence matrix is given. The principal elements of the matrix are commutators and output signal shapers. The matrix uses 138-series microcircuits. The resolution time of coincidence circuits is 10 ns, the dead time is 25 ns. The results of testing the matrix during experiments under conditions of a high background of accidental coincidences (70-90%) have shown that the accuracy of discrimination of true coincidences with the help of the double-coincidence matrix approximates the accuracy of time-to-digital converters within the limits of the statistical accuracy

  8. Fermionic matrix models

    CERN Document Server

    Semenoff, Gordon W; Semenoff, Gordon W; Szabo, Richard J

    1996-01-01

    We review a class of matrix models whose degrees of freedom are matrices with anticommuting elements. We discuss the properties of the adjoint fermion one-, two- and gauge invariant D-dimensional matrix models at large-N and compare them with their bosonic counterparts which are the more familiar Hermitian matrix models. We derive and solve the complete sets of loop equations for the correlators of these models and use these equations to examine critical behaviour. The topological large-N expansions are also constructed and their relation to other aspects of modern string theory such as integrable hierarchies is discussed. We use these connections to discuss the applications of these matrix models to string theory and induced gauge theories. We argue that as such the fermionic matrix models may provide a novel generalization of the discretized random surface representation of quantum gravity in which the genus sum alternates and the sums over genera for correlators have better convergence properties than thei...

  9. Time rate collision matrix

    International Nuclear Information System (INIS)

    The collision integral terms in Boltzmann equation are reformulated numerically leading to the substitution of the multiple integrals with a multiplicative matrix of the two colliding species velocity distribution functions which varies with the differential collision cross section. A matrix of lower rank may be constructed when one of the distribution functions is specified, in which case the matrix elements represent kinetic transition probabilities in the velocity space and the multiplication of the time rate collision matrix with the unknown velocity distribution function expresses the time rate of change of the distribution. The collision matrix may be used to describe the time evolution of systems in nonequilibrium conditions, to evaluate the rate of momentum and energy transfer between given species, or to generate validity criteria for linearized kinetic equations

  10. Matrix comparison, Part 2

    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...... and evaluate the degree of monotonicity between different proximity measures or their ordination results. In common with these techniques is the application of permutation procedures to test hypotheses about matrix resemblances. The choice of technique is related to the validation at hand. In the case...

  11. The shell organic matrix of the crossed lamellar queen conch shell (Strombus gigas).

    Science.gov (United States)

    Osuna-Mascaró, Antonio; Cruz-Bustos, Teresa; Benhamada, Sana; Guichard, Nathalie; Marie, Benjamin; Plasseraud, Laurent; Corneillat, Marion; Alcaraz, Gérard; Checa, Antonio; Marin, Frédéric

    2014-02-01

    In molluscs, the shell organic matrix comprises a large set of biomineral-occluded proteins, glycoproteins and polysaccharides that are secreted by the calcifying mantle epithelium, and are supposed to display several functions related to the synthesis of the shell. In the present paper, we have characterized biochemically the shell matrix associated to the crossed-lamellar structure of the giant queen conch Strombus gigas. The acid-soluble (ASM) and acid-insoluble (AIM) matrices represent an extremely minor fraction of the shell. Both are constituted of polydisperse and of few discrete proteins among which three fractions, obtained by preparative SDS-PAGE and named 1P3, 2P3 and 3P3, are dominant and were further characterized. Compared to other matrices, the acid-soluble matrix is weakly glycosylated (3%) and among the discrete components, only 3P3 seems noticeably glycosylated. The monosaccharide composition of the ASM shows that mannose represents the main monosaccharide. To our knowledge, this is the first report of a high ratio of this sugar in a skeletal matrix. Furthermore, the ASM interacts with the in vitro crystallization of calcium carbonate, but this interaction is moderate. It differs from that of the isolated 1P3 fraction but is similar to that of the 2P3 and 3P3 fractions. At last, antibodies developed from the 3P3 fraction were used to localize this fraction within the shell by immunogold. This study is the first one aiming at characterizing the organic matrix associated to the crossed-lamellar structure of the queen conch shell. PMID:24291423

  12. Conditional targeting of medium spiny neurons in the striatal matrix

    Directory of Open Access Journals (Sweden)

    Björn eReinius

    2015-03-01

    Full Text Available The striatum serves as the main input to the basal ganglia, and is key for the regulation of motor behaviors, compulsion, addiction, and various cognitive and emotional states. Its deterioration is associated with degenerative disorders such as Huntington’s diseases. Despite its apparent anatomical uniformity, it consists of intermingled cell populations, which have precluded straightforward anatomical sub-classifications adhering to functional dissections. Approximately 95% of the striatal neurons are inhibitory projection neurons termed medium spiny neurons (MSNs. They are commonly classified according to their expression of either dopamine receptor D1 or D2, which also determines their axonal projection patterns constituting the direct and indirect pathway in the basal ganglia. Immunohistochemical patterns have further indicated compartmentalization of the striatum to the striosomes and the surrounding matrix, which integrate MSNs of both the D1 and D2 type. Here, we present a transgenic mouse line, Gpr101-Cre, with Cre recombinase activity localized to matrix D1 and D2 MSNs. Using two Gpr101-Cre founder lines with different degrees of expression in the striatum, we conditionally deleted the vesicular inhibitory amino acid transporter (VIAAT, responsible for storage of GABA and glycine in synaptic vesicles. Partial ablation of VIAAT (in ~36% of MSNs resulted in elevated locomotor activity compared to control mice, when provoked with the monoamine reuptake inhibitor cocaine. Near complete targeting of matrix MSNs led to profoundly changed motor behaviors, which increased in severity as the mice aged. Moreover, these mice had exaggerated muscle rigidity, retarded growth, increased rate of spontaneous deaths, and defective memory. Therefore, our data provide a link between dysfunctional GABA signaling of matrix MSNs to specific behavioral alterations, which are similar to the symptoms of Huntington’s disease.

  13. Similarity Measures for Comparing Biclusterings.

    Science.gov (United States)

    Horta, Danilo; Campello, Ricardo J G B

    2014-01-01

    The comparison of ordinary partitions of a set of objects is well established in the clustering literature, which comprehends several studies on the analysis of the properties of similarity measures for comparing partitions. However, similarity measures for clusterings are not readily applicable to biclusterings, since each bicluster is a tuple of two sets (of rows and columns), whereas a cluster is only a single set (of rows). Some biclustering similarity measures have been defined as minor contributions in papers which primarily report on proposals and evaluation of biclustering algorithms or comparative analyses of biclustering algorithms. The consequence is that some desirable properties of such measures have been overlooked in the literature. We review 14 biclustering similarity measures. We define eight desirable properties of a biclustering measure, discuss their importance, and prove which properties each of the reviewed measures has. We show examples drawn and inspired from important studies in which several biclustering measures convey misleading evaluations due to the absence of one or more of the discussed properties. We also advocate the use of a more general comparison approach that is based on the idea of transforming the original problem of comparing biclusterings into an equivalent problem of comparing clustering partitions with overlapping clusters. PMID:26356865

  14. Sparse Similarity-Based Fisherfaces

    DEFF Research Database (Denmark)

    Fagertun, Jens; Gomez, David Delgado; Hansen, Mads Fogtmann;

    2011-01-01

    intensities are used by Sparse Principal Component Analysis and Fisher Linear Discriminant Analysis to assign a one dimensional subspace projection to each person belonging to a reference data set. Experimental results performed in the AR dataset show that Similarity-based Fisherfaces in a sparse version can...

  15. HOW DISSIMILARLY SIMILAR ARE BIOSIMILARS?

    Directory of Open Access Journals (Sweden)

    Ramshankar Vijayalakshmi

    2012-05-01

    Full Text Available Recently Biopharmaceuticals are the new chemotherapeutical agents that are called as “Biosimilars” or “follow on protein products” by the European Medicines Agency (EMA and the American regulatory agencies (Food and Drug Administration respectively. Biosimilars are extremely similar to the reference molecule but not identical, however close their similarities may be. A regulatory framework is therefore in place to assess the application for marketing authorisation of biosimilars. When a biosimilar is similar to the reference biopharmaceutical in terms of safety, quality, and efficacy, it can be registered. It is important to document data from clinical trials with a view of similar safety and efficacy. If the development time for a generic medicine is around 3 years, a biosimilar takes about 6-9 years. Generic medicines need to demonstrate bioequivalence only unlike biosimilars that need to conduct phase I and Phase III clinical trials. In this review, different biosimilars that are already being used successfully in the field on Oncology is discussed. Their similarity, differences and guidelines to be followed before a clinically informed decision to be taken, is discussed. More importantly the regulatory guidelines that are operational in India with a work flow of making a biosimilar with relevant dos and dont’s are discussed. For a large populous country like India, where with improved treatments in all sectors including oncology, our ageing population is increasing. For the health care of this sector, we need more newer, cheaper and effective biosimilars in the market. It becomes therefore important to understand the regulatory guidelines and steps to come up with more biosimilars for the existing population and also more information is mandatory for the practicing clinicians to translate these effectively into clinical practice.

  16. Differential Effects of Domoic Acid and E. coli Lipopolysaccharide on Tumor Necrosis Factor-α, Transforming Growth Factor-β1 and Matrix Metalloproteinase-9 Release by Rat Neonatal Microglia: Evaluation of the Direct Activation Hypothesis

    Directory of Open Access Journals (Sweden)

    Sarath P. Gunasekera

    2007-09-01

    Full Text Available The excitatory amino acid domoic acid is the causative agent of amnesic shellfish poisoning in humans. The in vitro effects of domoic acid on rat neonatal brain microglia were compared with E. coli lipopolysaccharide (LPS, a known activator of microglia mediator release over a 4 to 24 hour observation period. LPS [3 ng/mL] but not domoic acid [1mM] stimulated a statistically significant increase in TNF-α mRNA and protein generation. Furthermore, both LPS and domoic acid did not significantly affect TGF- β1 gene expression and protein release. Finally, an in vitro exposure of microglia to LPS resulted in statistically significant MMP-9 expression and release, thus extending and confirming our previous observations. However, in contrast, no statistically significant increase in MMP-9 expression and release was observed after domoic acid treatment. Taken together our observations do not support the hypothesis that a short term (4 to 24 hours in vitro exposure to domoic acid, at a concentration toxic to neuronal cells, activates rat neonatal microglia and the concomitant release of the pro-inflammatory mediators tumor necrosis factor-α (TNF-α and matrix metalloproteinases-9 (MMP-9, as well as the anti- inflammatory cytokine transforming growth factor β1 (TGF-β1.

  17. Protein structure similarity from principle component correlation analysis

    Directory of Open Access Journals (Sweden)

    Chou James

    2006-01-01

    Full Text Available Abstract Background Owing to rapid expansion of protein structure databases in recent years, methods of structure comparison are becoming increasingly effective and important in revealing novel information on functional properties of proteins and their roles in the grand scheme of evolutionary biology. Currently, the structural similarity between two proteins is measured by the root-mean-square-deviation (RMSD in their best-superimposed atomic coordinates. RMSD is the golden rule of measuring structural similarity when the structures are nearly identical; it, however, fails to detect the higher order topological similarities in proteins evolved into different shapes. We propose new algorithms for extracting geometrical invariants of proteins that can be effectively used to identify homologous protein structures or topologies in order to quantify both close and remote structural similarities. Results We measure structural similarity between proteins by correlating the principle components of their secondary structure interaction matrix. In our approach, the Principle Component Correlation (PCC analysis, a symmetric interaction matrix for a protein structure is constructed with relationship parameters between secondary elements that can take the form of distance, orientation, or other relevant structural invariants. When using a distance-based construction in the presence or absence of encoded N to C terminal sense, there are strong correlations between the principle components of interaction matrices of structurally or topologically similar proteins. Conclusion The PCC method is extensively tested for protein structures that belong to the same topological class but are significantly different by RMSD measure. The PCC analysis can also differentiate proteins having similar shapes but different topological arrangements. Additionally, we demonstrate that when using two independently defined interaction matrices, comparison of their maximum

  18. The nuclear reaction matrix

    Energy Technology Data Exchange (ETDEWEB)

    Krenciglowa, E.M.; Kung, C.L.; Kuo, T.T.S.; Osnes, E.

    1976-09-24

    Different definitions of the reaction matrix G appropriate to the calculation of nuclear structure are reviewed and discussed. Qualitative physical arguments are presented in support of a two-step calculation of the G-matrix for finite nuclei. In the first step the high-energy excitations are included using orthogonalized plane-wave intermediate states, and in the second step the low-energy excitations are added in, using harmonic oscillator intermediate states. Accurate calculations of G-matrix elements for nuclear structure calculations in the Aapprox. =18 region are performed following this procedure and treating the Pauli exclusion operator Q/sub 2//sub p/ by the method of Tsai and Kuo. The treatment of Q/sub 2//sub p/, the effect of the intermediate-state spectrum and the energy dependence of the reaction matrix are investigated in detail. The present matrix elements are compared with various matrix elements given in the literature. In particular, close agreement is obtained with the matrix elements calculated by Kuo and Brown using approximate methods. (AIP)

  19. Faces of matrix models

    CERN Document Server

    Morozov, A

    2012-01-01

    Partition functions of eigenvalue matrix models possess a number of very different descriptions: as matrix integrals, as solutions to linear and non-linear equations, as tau-functions of integrable hierarchies and as special-geometry prepotentials, as result of the action of W-operators and of various recursions on elementary input data, as gluing of certain elementary building blocks. All this explains the central role of such matrix models in modern mathematical physics: they provide the basic "special functions" to express the answers and relations between them, and they serve as a dream model of what one should try to achieve in any other field.

  20. Elementary matrix theory

    CERN Document Server

    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

  1. Patience of matrix games

    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...... strategy uses a nonzero probability as small as image. This is done by constructing an explicit image nonsingular image matrix, for which the inverse has only nonnegative entries and where some of the entries are of value image....

  2. Mueller matrix differential decomposition.

    Science.gov (United States)

    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. PMID:21593943

  3. Retrieval of similar chess positions

    OpenAIRE

    Ganguly, Debasis; LEVELING, JOHANNES; Jones, Gareth J.F.

    2014-01-01

    We address the problem of retrieving chess game positions similar to a given query position from a collection of archived chess games. We investigate this problem from an information retrieval (IR) perspective. The advantage of our proposed IR-based approach is that it allows using the standard inverted organization of stored chess positions, leading to an ecient retrieval. Moreover, in contrast to retrieving exactly identical board positions, the IR-based approach is able to provide approxim...

  4. Scaling Group Testing Similarity Search

    OpenAIRE

    Iscen, Ahmet; Amsaleg, Laurent; Furon, Teddy

    2016-01-01

    The large dimensionality of modern image feature vectors, up to thousands of dimensions, is challenging the high dimensional indexing techniques. Traditional approaches fail at returning good quality results within a response time that is usable in practice. However, similarity search techniques inspired by the group testing framework have recently been proposed in an attempt to specifically defeat the curse of dimensionality. Yet, group testing does not scale and fails at indexing very large...

  5. SPATIO-TEXTUAL SIMILARITY JOIN

    Directory of Open Access Journals (Sweden)

    Ch Shylaja and Supreethi K.P

    2015-07-01

    Full Text Available Data mining is the process of discovering interesting patterns and knowledge from large amounts of data. Spatial databases store large space related data, such as maps, preprocessed remote sensing or medical imaging data. Modern mobile phones and mobile devices are equipped with GPS devices; this is the reason for the Location based services to gain significant attention. These Location based services generate large amounts of spatio- textual data which contain both spatial location and textual description. The spatiotextual objects have different representations because of deviations in GPS or due to different user descriptions. This calls for the need of efficient methods to integrate spatio-textual data. Spatio-textual similarity join meets this need. Spatio-textual similarity join: Given two sets of spatio-textual data, it finds all the similar pairs. Filter and refine framework will be developed to device the algorithms. The prefix filter technique will be extended to generate spatial and textual signatures and inverted indexes will be built on top of these signatures. Candidate pairs will be found using these indexes. Finally the candidate pairs will be refined to get the result. MBR-prefix based signature will be used to prune dissimilar objects. Hybrid signature will be used to support spatial and textual pruning simultaneously.

  6. Roget's Thesaurus and Semantic Similarity

    CERN Document Server

    Jarmasz, Mario

    2012-01-01

    We have implemented a system that measures semantic similarity using a computerized 1987 Roget's Thesaurus, and evaluated it by performing a few typical tests. We compare the results of these tests with those produced by WordNet-based similarity measures. One of the benchmarks is Miller and Charles' list of 30 noun pairs to which human judges had assigned similarity measures. We correlate these measures with those computed by several NLP systems. The 30 pairs can be traced back to Rubenstein and Goodenough's 65 pairs, which we have also studied. Our Roget's-based system gets correlations of .878 for the smaller and .818 for the larger list of noun pairs; this is quite close to the .885 that Resnik obtained when he employed humans to replicate the Miller and Charles experiment. We further evaluate our measure by using Roget's and WordNet to answer 80 TOEFL, 50 ESL and 300 Reader's Digest questions: the correct synonym must be selected amongst a group of four words. Our system gets 78.75%, 82.00% and 74.33% of ...

  7. Active browsing using similarity pyramids

    Science.gov (United States)

    Chen, Jau-Yuen; Bouman, Charles A.; Dalton, John C.

    1998-12-01

    In this paper, we describe a new approach to managing large image databases, which we call active browsing. Active browsing integrates relevance feedback into the browsing environment, so that users can modify the database's organization to suit the desired task. Our method is based on a similarity pyramid data structure, which hierarchically organizes the database, so that it can be efficiently browsed. At coarse levels, the similarity pyramid allows users to view the database as large clusters of similar images. Alternatively, users can 'zoom into' finer levels to view individual images. We discuss relevance feedback for the browsing process, and argue that it is fundamentally different from relevance feedback for more traditional search-by-query tasks. We propose two fundamental operations for active browsing: pruning and reorganization. Both of these operations depend on a user-defined relevance set, which represents the image or set of images desired by the user. We present statistical methods for accurately pruning the database, and we propose a new 'worm hole' distance metric for reorganizing the database, so that members of the relevance set are grouped together.

  8. Random matrix approach to categorical data analysis

    Science.gov (United States)

    Patil, Aashay; Santhanam, M. S.

    2015-09-01

    Correlation and similarity measures are widely used in all the areas of sciences and social sciences. Often the variables are not numbers but are instead qualitative descriptors called categorical data. We define and study similarity matrix, as a measure of similarity, for the case of categorical data. This is of interest due to a deluge of categorical data, such as movie ratings, top-10 rankings, and data from social media, in the public domain that require analysis. We show that the statistical properties of the spectra of similarity matrices, constructed from categorical data, follow random matrix predictions with the dominant eigenvalue being an exception. We demonstrate this approach by applying it to the data for Indian general elections and sea level pressures in the North Atlantic ocean.

  9. Biocompatible 3D Matrix with Antimicrobial Properties

    Directory of Open Access Journals (Sweden)

    Alberto Ion

    2016-01-01

    Full Text Available The aim of this study was to develop, characterize and assess the biological activity of a new regenerative 3D matrix with antimicrobial properties, based on collagen (COLL, hydroxyapatite (HAp, β-cyclodextrin (β-CD and usnic acid (UA. The prepared 3D matrix was characterized by Scanning Electron Microscopy (SEM, Fourier Transform Infrared Microscopy (FT-IRM, Transmission Electron Microscopy (TEM, and X-ray Diffraction (XRD. In vitro qualitative and quantitative analyses performed on cultured diploid cells demonstrated that the 3D matrix is biocompatible, allowing the normal development and growth of MG-63 osteoblast-like cells and exhibited an antimicrobial effect, especially on the Staphylococcus aureus strain, explained by the particular higher inhibitory activity of usnic acid (UA against Gram positive bacterial strains. Our data strongly recommend the obtained 3D matrix to be used as a successful alternative for the fabrication of three dimensional (3D anti-infective regeneration matrix for bone tissue engineering.

  10. Pesticide-Exposure Matrix

    Science.gov (United States)

    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.

  11. The Hill Interaction Matrix

    Science.gov (United States)

    Hill, William Fawcett

    1971-01-01

    Leadership style, group composition, and group development are simultaneously quantified through the use of the matrix. It represents an attempt to objectify the art of group therapy. Comment by Richard C. Rank follows. (Author)

  12. Measurement of Similarity for Spatial Directions Between Areal Objects

    Institute of Scientific and Technical Information of China (English)

    DING Hong; GUO Qingsheng; DU Xiaohu

    2004-01-01

    Similarity for spatial directions plays an important role in GIS. In this paper, the conventional approaches are analyzed. Based on raster data areal objects, the authors propose two new methods for measuring similarity among spatial directions. One is to measure the similarity among spatial directions based on the features of raster data and the changes of distances between spatial objects, the other is to measure the similarity among spatial directions according to the variation of each raster cell centroid angle. The two methods overcome the complexity of measuring similarity among spatial directions with direction matrix model and solve the limitation of small changes in direction. The two methods are simple and have broader applicability.

  13. Matrix Big Brunch

    OpenAIRE

    Bedford, J; Papageorgakis, C.; Rodriguez-Gomez, D.; Ward, J.

    2007-01-01

    Following the holographic description of linear dilaton null Cosmologies with a Big Bang in terms of Matrix String Theory put forward by Craps, Sethi and Verlinde, we propose an extended background describing a Universe including both Big Bang and Big Crunch singularities. This belongs to a class of exact string backgrounds and is perturbative in the string coupling far away from the singularities, both of which can be resolved using Matrix String Theory. We provide a simple theory capable of...

  14. Metal matrix Composites

    OpenAIRE

    Pradeep K. Rohatgi

    1993-01-01

    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 elec...

  15. Matrix fractional systems

    Science.gov (United States)

    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.

  16. 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)....

  17. Physiology and pathophysiology of matrix metalloproteases

    NARCIS (Netherlands)

    Klein, T.; Bischoff, R.

    2011-01-01

    Matrix metalloproteases (MMPs) comprise a family of enzymes that cleave protein substrates based on a conserved mechanism involving activation of an active site-bound water molecule by a Zn(2+) ion. Although the catalytic domain of MMPs is structurally highly similar, there are many differences with

  18. Effects of extracts of Dragon's blood on fibroblast proliferation and extracellular matrix hyaluronic acid%血竭提取物对成纤维细胞增殖及合成透明质酸的影响

    Institute of Scientific and Technical Information of China (English)

    李丹; 惠瑞; 胡咏武; 韩岩; 郭树忠

    2015-01-01

    Objective To investigate the effects of Dragon' s blood extract on proliferation and secret extracellular matrix function of fibroblasts in vitro.Methods Dragon ' s blood was extracted by chloroform,acetoacetic ester,alcohol.Human fibroblast were cultured in vitro in media containing gradient dilutions of Dragon's blood extracts (0.002,0.02,0.2,2,20 mg/ml),which was followed by cell proliferation assessed with MTT assay on 0,12,24,36,48,60,72 h.Under the optimal concentration,the cell growth curves were drawn and the flow cytometry (FCM) was used to determine the changes of cell cycle.On 0,12,24,36,48,60,72 h,the concentration of hyaluronic acid in the supernatant of fibroblast culture was measured by radioimmunoassay.Results 0.2-2 mg/ml Dragon' s blood extracts enhanced the proliferation of fibroblasts in a dose-dependent manner.2 mg/ml was the optimal dilution of Dragon' s blood extract,and it increased the ratio of S cells in cell cycle[(25.80 ± 3.10) %] than control group[(7.50 ± 0.70)%,P < 0.01].From 12 h to 72 h,in 2 mg/ml Dragon's blood group,concentration of Hyaluronic acid secreted by fibroblasts gradually increased,but were less than control(P < 0.01).Conclusions Dragon ' s blood acetoacetic ester extract improved the proliferation of cultured human fibroblasts in vitro,might be beneficial to promote wound healing.%目的 研究血竭提取物对成纤维细胞生物学作用的影响.方法 将血竭经过氯仿、乙酸乙酯、乙醇依次回流提取分别得到3种血竭提取液,培养液稀释后行成纤维细胞培养.噻唑蓝法MTT检测浓度分别为0.002、0.02、0.2、2、20 mg/ml的血竭提取物,在0、12、24、36、48、60、72h7个检测点对体外培养成纤维细胞增殖的影响,并绘制最适浓度下细胞生长曲线.流式细胞术FCM分析最适浓度培养下成纤维细胞的细胞周期变化.应用放射免疫分析法检测0、12、24、36、48、60、72 h细胞培养上清液中透明质酸(hyaluronic acid

  19. A Text Similarity Matrix Operation-Based Classification Algorithm for Large-scale Unstructured Complaint Data%一种基于文本相似度矩阵运算的非结构化海量投诉数据分类算法

    Institute of Scientific and Technical Information of China (English)

    李青; 陈阳; 谢浩然; 蒙圣光

    2012-01-01

    With the fast development of the Internet and information technology nowadays, the growth of the volume of unstructured data is exponential. In particular, the prevalence of the Web 2. 0 network community further enlarges the growth tendency. Therefore, how to manage and organize large-scale unstructured data effectively, so as to facilitate end-user information access, becomes an urgent and important research topic. In this paper, based on the text of unstructured data modeling and text similarity, the existing large-scale unstructured data classification algorithms are surveyed and discussed, and they are applied to a China Mobile user complaint data classification system. Upon the latter, the effectiveness of processing the complaint data is shown to have been much improved, and the usage of our proposed classification algorithm and system architecture is verified.%随着互联网和信息技术的日新月异,非结构化数据量有呈几何级数增长的趋势.尤其是Web 2.0网络社区的流行与火爆,使得增长趋势得到了进一步的加速.因此,面对海量的非结构化数据,如何有效地管理和组织它们,以便于终端用户进行信息存取,成为了一个迫在眉睫的重要研究课题.本文通过对非结构化数据的文本的建模和文本相似度比较,对于大规模非结构化数据的分类算法进行了讨论和研究,并将此算法应用到了中国移动的投诉数据分类系统中.在系统实施后,非常有效地提高了投诉数据的处理效率,从而印证所提出分类算法及系统框架的有效性.

  20. Bosonic Matrix Theory and Matrix Dbranes

    OpenAIRE

    Chaudhuri, Shyamoli

    2002-01-01

    We develop new tools for an in-depth study of our recent proposal for Matrix Theory. We construct the anomaly-free and finite planar continuum limit of the ground state with SO(2^{13}) symmetry matching with the tadpole and tachyon free IR stable high temperature ground state of the open and closed bosonic string. The correspondence between large N limits and spacetime effective actions is demonstrated more generally for an arbitrary D25brane ground state which might include brane-antibrane p...

  1. Mechanisms for similarity based cooperation

    Science.gov (United States)

    Traulsen, A.

    2008-06-01

    Cooperation based on similarity has been discussed since Richard Dawkins introduced the term “green beard” effect. In these models, individuals cooperate based on an aribtrary signal (or tag) such as the famous green beard. Here, two different models for such tag based cooperation are analysed. As neutral drift is important in both models, a finite population framework is applied. The first model, which we term “cooperative tags” considers a situation in which groups of cooperators are formed by some joint signal. Defectors adopting the signal and exploiting the group can lead to a breakdown of cooperation. In this case, conditions are derived under which the average abundance of the more cooperative strategy exceeds 50%. The second model considers a situation in which individuals start defecting towards others that are not similar to them. This situation is termed “defective tags”. It is shown that in this case, individuals using tags to cooperate exclusively with their own kind dominate over unconditional cooperators.

  2. Evaluation of New Diagnostic Biomarkers in Pediatric Sepsis: Matrix Metalloproteinase-9, Tissue Inhibitor of Metalloproteinase-1, Mid-Regional Pro-Atrial Natriuretic Peptide, and Adipocyte Fatty-Acid Binding Protein.

    Directory of Open Access Journals (Sweden)

    Mashael F Alqahtani

    Full Text Available Elevated plasma concentrations of matrix metalloproteinase-9 (MMP-9, tissue inhibitor of metalloproteinase-1 (TIMP-1, mid-regional pro-atrial natriuretic peptide (mrProANP, and adipocyte fatty-acid-binding proteins (A-FaBPs have been investigated as biomarkers for sepsis or detection of acute neurological injuries in adults, but not children. We carried out a single-center, prospective observational study to determine if these measures could serve as biomarkers to identify children with sepsis. A secondary aim was to determine if these biomarkers could identify children with neurologic complications of sepsis. A total of 90 patients ≤ 18 years-old were included in this study. 30 with severe sepsis or septic shock were compared to 30 age-matched febrile and 30 age-matched healthy controls. Serial measurements of each biomarker were obtained, beginning on day 1 of ICU admission. In septic patients, MMP9-/TIMP-1 ratios (Median, IQR, n were reduced on day 1 (0.024, 0.004-0.174, 13, day 2 (0.020, 0.002-0.109, 10, and day 3 (0.018, 0.003-0.058, 23 compared with febrile (0.705, 0.187-1.778, 22 and healthy (0.7, 0.4-1.2, 29 (p< 0.05 controls. A-FaBP and mrProANP (Median, IQR ng/mL, n were elevated in septic patients compared to control groups on first 2 days after admission to the PICU (p <0.05. The area under the curve (AUC for MMP-9/TIMP-1 ratio, mrProANP, and A-FaBP to distinguish septic patients from healthy controls were 0.96, 0.99, and 0.76, respectively. MMP-9/TIMP-1 ratio was inversely and mrProANP was directly related to PIM-2, PELOD, and ICU and hospital LOS (p<0.05. A-FaBP level was associated with PELOD, hospital and ICU length of stay (p<0.05. MMP-9/TIMP-1 ratio associated with poor Glasgow Outcome Score (p<0.05. A-FaBP levels in septic patients with neurological dysfunction (29.3, 17.2-54.6, 7 were significantly increased compared to septic patients without neurological dysfunction (14.6, 13.3-20.6, 11. MMP-9/TIMP-1 ratios were

  3. Matricial bridges for "Matrix algebras converge to the sphere"

    OpenAIRE

    Rieffel, Marc A.

    2015-01-01

    In the high-energy quantum-physics literature one finds statements such as "matrix algebras converge to the sphere". Earlier I provided a general setting for understanding such statements, in which the matrix algebras are viewed as quantum metric spaces, and convergence is with respect to a quantum Gromov-Hausdorff-type distance. In the present paper, as preparation of discussing similar statements for convergence of "vector bundles" over matrix algebras to vector bundles over spaces, we intr...

  4. Symmetries of the 2D magnetic particle imaging system matrix

    International Nuclear Information System (INIS)

    In magnetic particle imaging (MPI), the relation between the particle distribution and the measurement signal can be described by a linear system of equations. For 1D imaging, it can be shown that the system matrix can be expressed as a product of a convolution matrix and a Chebyshev transformation matrix. For multidimensional imaging, the structure of the MPI system matrix is not yet fully explored as the sampling trajectory complicates the physical model. It has been experimentally found that the MPI system matrix rows have symmetries and look similar to the tensor products of Chebyshev polynomials. In this work we will mathematically prove that the 2D MPI system matrix has symmetries that can be used for matrix compression. (paper)

  5. Ion-to-Neutral Ratios and Thermal Proton Transfer in Matrix-Assisted Laser Desorption/Ionization

    Science.gov (United States)

    Lu, I.-Chung; Chu, Kuan Yu; Lin, Chih-Yuan; Wu, Shang-Yun; Dyakov, Yuri A.; Chen, Jien-Lian; Gray-Weale, Angus; Lee, Yuan-Tseh; Ni, Chi-Kung

    2015-07-01

    The ion-to-neutral ratios of four commonly used solid matrices, α-cyano-4-hydroxycinnamic acid (CHCA), 2,5-dihydroxybenzoic acid (2,5-DHB), sinapinic acid (SA), and ferulic acid (FA) in matrix-assisted laser desorption/ionization (MALDI) at 355 nm are reported. Ions are measured using a time-of-flight mass spectrometer combined with a time-sliced ion imaging detector. Neutrals are measured using a rotatable quadrupole mass spectrometer. The ion-to-neutral ratios of CHCA are three orders of magnitude larger than those of the other matrices at the same laser fluence. The ion-to-neutral ratios predicted using the thermal proton transfer model are similar to the experimental measurements, indicating that thermal proton transfer reactions play a major role in generating ions in ultraviolet-MALDI.

  6. Ion-to-Neutral Ratios and Thermal Proton Transfer in Matrix-Assisted Laser Desorption/Ionization.

    Science.gov (United States)

    Lu, I-Chung; Chu, Kuan Yu; Lin, Chih-Yuan; Wu, Shang-Yun; Dyakov, Yuri A; Chen, Jien-Lian; Gray-Weale, Angus; Lee, Yuan-Tseh; Ni, Chi-Kung

    2015-07-01

    The ion-to-neutral ratios of four commonly used solid matrices, α-cyano-4-hydroxycinnamic acid (CHCA), 2,5-dihydroxybenzoic acid (2,5-DHB), sinapinic acid (SA), and ferulic acid (FA) in matrix-assisted laser desorption/ionization (MALDI) at 355 nm are reported. Ions are measured using a time-of-flight mass spectrometer combined with a time-sliced ion imaging detector. Neutrals are measured using a rotatable quadrupole mass spectrometer. The ion-to-neutral ratios of CHCA are three orders of magnitude larger than those of the other matrices at the same laser fluence. The ion-to-neutral ratios predicted using the thermal proton transfer model are similar to the experimental measurements, indicating that thermal proton transfer reactions play a major role in generating ions in ultraviolet-MALDI.

  7. Semantically enabled image similarity search

    Science.gov (United States)

    Casterline, May V.; Emerick, Timothy; Sadeghi, Kolia; Gosse, C. A.; Bartlett, Brent; Casey, Jason

    2015-05-01

    Georeferenced data of various modalities are increasingly available for intelligence and commercial use, however effectively exploiting these sources demands a unified data space capable of capturing the unique contribution of each input. This work presents a suite of software tools for representing geospatial vector data and overhead imagery in a shared high-dimension vector or embedding" space that supports fused learning and similarity search across dissimilar modalities. While the approach is suitable for fusing arbitrary input types, including free text, the present work exploits the obvious but computationally difficult relationship between GIS and overhead imagery. GIS is comprised of temporally-smoothed but information-limited content of a GIS, while overhead imagery provides an information-rich but temporally-limited perspective. This processing framework includes some important extensions of concepts in literature but, more critically, presents a means to accomplish them as a unified framework at scale on commodity cloud architectures.

  8. Performance Indexes: Similarities and Differences

    Directory of Open Access Journals (Sweden)

    André Machado Caldeira

    2013-06-01

    Full Text Available The investor of today is more rigorous on monitoring a financial assets portfolio. He no longer thinks only in terms of the expected return (one dimension, but in terms of risk-return (two dimensions. Thus new perception is more complex, since the risk measurement can vary according to anyone’s perception; some use the standard deviation for that, others disagree with this measure by proposing others. In addition to this difficulty, there is the problem of how to consider these two dimensions. The objective of this essay is to study the main performance indexes through an empirical study in order to verify the differences and similarities for some of the selected assets. One performance index proposed in Caldeira (2005 shall be included in this analysis.

  9. Features Based Text Similarity Detection

    CERN Document Server

    Kent, Chow Kok

    2010-01-01

    As the Internet help us cross cultural border by providing different information, plagiarism issue is bound to arise. As a result, plagiarism detection becomes more demanding in overcoming this issue. Different plagiarism detection tools have been developed based on various detection techniques. Nowadays, fingerprint matching technique plays an important role in those detection tools. However, in handling some large content articles, there are some weaknesses in fingerprint matching technique especially in space and time consumption issue. In this paper, we propose a new approach to detect plagiarism which integrates the use of fingerprint matching technique with four key features to assist in the detection process. These proposed features are capable to choose the main point or key sentence in the articles to be compared. Those selected sentence will be undergo the fingerprint matching process in order to detect the similarity between the sentences. Hence, time and space usage for the comparison process is r...

  10. Processing of continuous fiber composites using thermoplastic polyimide matrix resins

    Energy Technology Data Exchange (ETDEWEB)

    Kranjc, M.D.

    1993-01-01

    Composites have been produced which contain a solvent resistant polyimide matrix with favorable physical properties. The polyimide matrix resin has been designated as P12. The prepegs used to produce the composite contain a low molecular weight resin which is the polyamic acid precursor to P12. Polymerization and imidization of the precursor resin occurs in-situ during processing. Similar commercial systems are often processed in an autoclave and pressure is used at high temperatures to obtain consolidation between prepreg laminates. Pressure is generally applied after polymerization and imidization are complete and at temperatures above the melting point of the polymer. In this research a significant decrease in composite void content was obtained by applying pressure earlier in the cure. Obtaining composites with low void content with these types of systems can be difficult. This is due in part to the generation of low molecular weight reaction by products, water and methanol. High void content results in a decrease in the physical properties of the composite structure. This is especially true for fracture properties. An empirical equation was used to describe the rate of resin removal from the composite to the bleeder cloth during processing. This equation is based on Springer-Loos resin flow model. The conditions in which this model does not apply were also determined. Determining resin removal rates is helpful in producing composites with consistent fiber/resin ratios. In addition, conditions which favor void growth can be prevented.

  11. One anlytic form for four branches of the ABCD matrix

    CERN Document Server

    Baskal, S

    2010-01-01

    It is not always possible to diagonalize the optical $ABCD$ matrix, but it can be brought into one of the four Wigner matrices by a similarity transformation. It is shown that the four Wigner matrices can be combined into one matrix with four branches. This result is illustrated in terms of optical activities, laser cavities, and multilayer optics.

  12. Matrix Information Geometry

    CERN Document Server

    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.  

  13. A Novel MALDI Matrix for Analyzing Peptides and Proteins: Paraffin Wax Immobilized Matrix

    Institute of Scientific and Technical Information of China (English)

    WEI Yuanlong; MEI Yuan; XU Zhe; WANG Cuihong; GUO Yinlong; DU Yiping; ZHANG Weibing

    2009-01-01

    A new kind of MALDI matrix, termed paraffin wax immobilized matrix, was used to study peptide mixtures and proteins. During the preparation process, the paraffin wax was heated and coated on the stainless-steel target plate, and then 2,5-dihydrobenzoic acid (DHB) was deposited on the paraffin layer and stainless-steel target plate to obtain different kinds of matrix spots. The morphology of matrices on different supports and peptide-matrix co-crystallization were observed by a high resolution digital-video microscopy system. Peptide mixtures and bovine serum albumin (BSA) digests were used to investigate the performance of the immobilized matrices on the paraffin target. The MALDI-FTMS analysis results also showed that the detection sensitivity of matrices immobilized in the paraffin sample support was better than that on other sample supports.

  14. Alaska, Gulf spills share similarities

    International Nuclear Information System (INIS)

    The accidental Exxon Valdez oil spill in Alaska and the deliberate dumping of crude oil into the Persian Gulf as a tactic of war contain both glaring differences and surprising similarities. Public reaction and public response was much greater to the Exxon Valdez spill in pristine Prince William Sound than to the war-related tragedy in the Persian Gulf. More than 12,000 workers helped in the Alaskan cleanup; only 350 have been involved in Kuwait. But in both instances, environmental damages appear to be less than anticipated. Natures highly effective self-cleansing action is primarily responsible for minimizing the damages. One positive action growing out of the two incidents is increased international cooperation and participation in oil-spill clean-up efforts. In 1990, in the aftermath of the Exxon Valdez spill, 94 nations signed an international accord on cooperation in future spills. The spills can be historic environmental landmarks leading to creation of more sophisticated response systems worldwide

  15. Relativistic Self-similar Disks

    CERN Document Server

    Cai, M J; Cai, Mike J.; Shu, Frank H.

    2002-01-01

    We formulate and solve by semi-analytic means the axisymmetric equilibria of relativistic self-similar disks of infinitesimal vertical thickness. These disks are supported in the horizontal directions against their self-gravity by a combination of isothermal (two-dimensional) pressure and a flat rotation curve. The dragging of inertial frames restricts possible solutions to rotation speeds that are always less than 0.438 times the speed of light, a result first obtained by Lynden-Bell and Pineault in 1978 for a cold disk. We show that prograde circular orbits of massive test particles exist and are stable for all of our model disks, but retrograde circular orbits cannot be maintained with particle velocities less than the speed of light once the disk develops an ergoregion. We also compute photon trajectories, planar and non-planar, in the resulting spacetime, for disks with and without ergoregions. We find that all photon orbits, except for a set of measure zero, tend to be focused by the gravity of the flat...

  16. Retinoid-binding proteins: similar protein architectures bind similar ligands via completely different ways.

    Directory of Open Access Journals (Sweden)

    Yu-Ru Zhang

    Full Text Available BACKGROUND: Retinoids are a class of compounds that are chemically related to vitamin A, which is an essential nutrient that plays a key role in vision, cell growth and differentiation. In vivo, retinoids must bind with specific proteins to perform their necessary functions. Plasma retinol-binding protein (RBP and epididymal retinoic acid binding protein (ERABP carry retinoids in bodily fluids, while cellular retinol-binding proteins (CRBPs and cellular retinoic acid-binding proteins (CRABPs carry retinoids within cells. Interestingly, although all of these transport proteins possess similar structures, the modes of binding for the different retinoid ligands with their carrier proteins are different. METHODOLOGY/PRINCIPAL FINDINGS: In this work, we analyzed the various retinoid transport mechanisms using structure and sequence comparisons, binding site analyses and molecular dynamics simulations. Our results show that in the same family of proteins and subcellular location, the orientation of a retinoid molecule within a binding protein is same, whereas when different families of proteins are considered, the orientation of the bound retinoid is completely different. In addition, none of the amino acid residues involved in ligand binding is conserved between the transport proteins. However, for each specific binding protein, the amino acids involved in the ligand binding are conserved. The results of this study allow us to propose a possible transport model for retinoids. CONCLUSIONS/SIGNIFICANCE: Our results reveal the differences in the binding modes between the different retinoid-binding proteins.

  17. MATLAB matrix algebra

    CERN Document Server

    Pérez López, César

    2014-01-01

    MATLAB is a high-level language and environment for numerical computation, visualization, and programming. Using MATLAB, you can analyze data, develop algorithms, and create models and applications. The language, tools, and built-in math functions enable you to explore multiple approaches and reach a solution faster than with spreadsheets or traditional programming languages, such as C/C++ or Java. MATLAB Matrix Algebra introduces you to the MATLAB language with practical hands-on instructions and results, allowing you to quickly achieve your goals. Starting with a look at symbolic and numeric variables, with an emphasis on vector and matrix variables, you will go on to examine functions and operations that support vectors and matrices as arguments, including those based on analytic parent functions. Computational methods for finding eigenvalues and eigenvectors of matrices are detailed, leading to various matrix decompositions. Applications such as change of bases, the classification of quadratic forms and ...

  18. Finite Temperature Matrix Theory

    CERN Document Server

    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.

  19. Dynamic Matrix Rank

    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) 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...... 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....

  20. Whitby Mudstone, flow from matrix to fractures

    Science.gov (United States)

    Houben, Maartje; Hardebol, Nico; Barnhoorn, Auke; Boersma, Quinten; Peach, Colin; Bertotti, Giovanni; Drury, Martyn

    2016-04-01

    Fluid flow from matrix to well in shales would be faster if we account for the duality of the permeable medium considering a high permeable fracture network together with a tight matrix. To investigate how long and how far a gas molecule would have to travel through the matrix until it reaches an open connected fracture we investigated the permeability of the Whitby Mudstone (UK) matrix in combination with mapping the fracture network present in the current outcrops of the Whitby Mudstone at the Yorkshire coast. Matrix permeability was measured perpendicular to the bedding using a pressure step decay method on core samples and permeability values are in the microdarcy range. The natural fracture network present in the pavement shows a connected network with dominant NS and EW strikes, where the NS fractures are the main fracture set with an orthogonal fracture set EW. Fracture spacing relations in the pavements show that the average distance to the nearest fracture varies between 7 cm (EW) and 14 cm (NS), where 90% of the matrix is 30 cm away from the nearest fracture. By making some assumptions like; fracture network at depth is similar to what is exposed in the current pavements and open to flow, fracture network is at hydrostatic pressure at 3 km depth, overpressure between matrix and fractures is 10% and a matrix permeability perpendicular to the bedding of 0.1 microdarcy, we have calculated the time it takes for a gas molecule to travel to the nearest fracture. These input values give travel times up to 8 days for a distance of 14 cm. If the permeability is changed to 1 nanodarcy or 10 microdarcy travel times change to 2.2 years or 2 hours respectively.

  1. DIY Bertin Matrix

    OpenAIRE

    Perin, Charles; Le Goc, Mathieu; Di Vozzo, Romain; Fekete, Jean-Daniel; Dragicevic, Pierre

    2015-01-01

    In this paper, we relate the iterative fabrication of a physical Bertin Matrix. Jacques Bertin designed and refined such devices over 10 years (1970–1980) and five iterations of what he called Dominos 1–5. For the purpose of an exhibit dedicated to Bertin's work during VIS 2014 in Paris, we designed an improved version of such device by leveraging modern fabrication possibilities and in particular a laser cutter. We describe the process, iterations and improvements of our matrix, and report l...

  2. Reduced Google matrix

    CERN Document Server

    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.

  3. Elementary matrix algebra

    CERN Document Server

    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

  4. A nonsupersymmetric matrix orbifold

    OpenAIRE

    Banks, Tom; Motl, Lubos

    1999-01-01

    We construct the matrix description for a twisted version of the IIA string theory on S^1 with fermions antiperiodic around a spatial circle. The result is a 2+1-dimensional U(N) x U(N) nonsupersymmetric Yang-Mills theory with fermionic matter transforming in the (N,Nbar). The two U(N)'s are exchanged if one goes around a twisted circle of the worldvolume. Relations with Type 0 theories are explored and we find Type 0 matrix string limits of our gauge theory. We argue however that most of the...

  5. Complex matrix model duality

    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.)

  6. Complex matrix model duality

    International Nuclear Information System (INIS)

    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.)

  7. Identification of the nuclear matrix and chromosome scaffold in dinoflagellate Crypthecodinium cohnii

    Institute of Scientific and Technical Information of China (English)

    CAISHUTAO; CONGMEIZENG; 等

    1992-01-01

    Dinolflagellate is one of the primitive eukaryotes,whose nucleus may represent one of the transition stages from prokaryotic nucleoid to typical eukaryotic nucleus,Using selective extraction together with embeddment-free section and whole mount electron microscopy,a delicate nuclear matrix filament network was shown,for the first time,in dinoflagellate Crypthecodinium cohnii nucleus,Chromosome residues are connected with nuclear matrix filaments to form a complete network spreading over the nucleus,Moreover,we demonstrated that the dinoflagellate chromosome retains a protein scafflod after the depletion of DNA and soluble proteins.This scaffold preserves the characterstic morphology of the chromosome.Two dimensional electrophoreses indicated that the nuclear matrix and chromosome scaffold are mainly composed of acidic proteins.Our results demonstrated that a framework similar th the nuclear matrix and chromosome scaffold in mammalian cells appears in this primitive eukaryote,suggesting that these structures may have been originated from the early stages of eukaryote evolution.

  8. 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.

  9. Similarities between decapod and insect neuropeptidomes

    Science.gov (United States)

    2016-01-01

    Background. Neuropeptides are important regulators of physiological processes and behavior. Although they tend to be generally well conserved, recent results using trancriptome sequencing on decapod crustaceans give the impression of significant differences between species, raising the question whether such differences are real or artefacts. Methods. The BLAST+ program was used to find short reads coding neuropeptides and neurohormons in publicly available short read archives. Such reads were then used to find similar reads in the same archives, and the DNA assembly program Trinity was employed to construct contigs encoding the neuropeptide precursors as completely as possible. Results. The seven decapod species analyzed in this fashion, the crabs Eriocheir sinensis, Carcinus maenas and Scylla paramamosain, the shrimp Litopenaeus vannamei, the lobster Homarus americanus, the fresh water prawn Macrobrachium rosenbergii and the crayfish Procambarus clarkii had remarkably similar neuropeptidomes. Although some neuropeptide precursors could not be assembled, in many cases individual reads pertaining to the missing precursors show unambiguously that these neuropeptides are present in these species. In other cases, the tissues that express those neuropeptides were not used in the construction of the cDNA libraries. One novel neuropeptide was identified: elongated PDH (pigment dispersing hormone), a variation on PDH that has a two-amino-acid insertion in its core sequence. Hyrg is another peptide that is ubiquitously present in decapods and is likely a novel neuropeptide precursor. Discussion. Many insect species have lost one or more neuropeptide genes, but apart from elongated PDH and hyrg all other decapod neuropeptides are present in at least some insect species, and allatotropin is the only insect neuropeptide missing from decapods. This strong similarity between insect and decapod neuropeptidomes makes it possible to predict the receptors for decapod neuropeptides

  10. Similarities between decapod and insect neuropeptidomes.

    Science.gov (United States)

    Veenstra, Jan A

    2016-01-01

    Background. Neuropeptides are important regulators of physiological processes and behavior. Although they tend to be generally well conserved, recent results using trancriptome sequencing on decapod crustaceans give the impression of significant differences between species, raising the question whether such differences are real or artefacts. Methods. The BLAST+ program was used to find short reads coding neuropeptides and neurohormons in publicly available short read archives. Such reads were then used to find similar reads in the same archives, and the DNA assembly program Trinity was employed to construct contigs encoding the neuropeptide precursors as completely as possible. Results. The seven decapod species analyzed in this fashion, the crabs Eriocheir sinensis, Carcinus maenas and Scylla paramamosain, the shrimp Litopenaeus vannamei, the lobster Homarus americanus, the fresh water prawn Macrobrachium rosenbergii and the crayfish Procambarus clarkii had remarkably similar neuropeptidomes. Although some neuropeptide precursors could not be assembled, in many cases individual reads pertaining to the missing precursors show unambiguously that these neuropeptides are present in these species. In other cases, the tissues that express those neuropeptides were not used in the construction of the cDNA libraries. One novel neuropeptide was identified: elongated PDH (pigment dispersing hormone), a variation on PDH that has a two-amino-acid insertion in its core sequence. Hyrg is another peptide that is ubiquitously present in decapods and is likely a novel neuropeptide precursor. Discussion. Many insect species have lost one or more neuropeptide genes, but apart from elongated PDH and hyrg all other decapod neuropeptides are present in at least some insect species, and allatotropin is the only insect neuropeptide missing from decapods. This strong similarity between insect and decapod neuropeptidomes makes it possible to predict the receptors for decapod neuropeptides

  11. Inequalities Involving Upper Bounds for Certain Matrix Operators

    Indian Academy of Sciences (India)

    R Lashkaripour; D Foroutannia

    2006-08-01

    In this paper, we considered the problem of finding the upper bound Hausdorff matrix operator from sequence spaces $l_p(v)$ (or $d(v,p)$) into $l_p(w)$ (or $d(w, p)$). Also we considered the upper bound problem for matrix operators from $d(v,1)$ into $d(w,1)$, and matrix operators from $e(w,∞)$ into $e(v,∞)$, and deduce upper bound for Cesaro, Copson and Hilbert matrix operators, which are recently considered in [5] and [6] and similar to that in [10].

  12. Event matrix system

    International Nuclear Information System (INIS)

    The number of background events in nuclear and particle physics experiments which use multiwire proportional chambers can be extremely high. Using a computer to resolve these events results in a high deadtime for the experiment. A fast matrix system for decreasing the number of background events is described in this report. 4 figures

  13. Matrix Embedded Organic Synthesis

    Science.gov (United States)

    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.

  14. Challenging the CSCW matrix

    DEFF Research Database (Denmark)

    Jørnø, Rasmus Leth Vergmann; Gynther, Karsten; Christensen, Ove

    2014-01-01

    useful information, we question whether the axis of time and space comprising the matrix pertains to relevant defining properties of the tools, technology or learning environments to which they are applied. Subsequently we offer an example of an Adobe Connect e-learning session as an illustration...

  15. Matrix model holography

    OpenAIRE

    Ortiz, Thomas; Samtleben, Henning; Tsimpis, Dimitrios

    2014-01-01

    We set up the formalism of holographic renormalization for the matter-coupled two-dimensional maximal supergravity that captures the low-lying fluctuations around the non-conformal D0-brane near-horizon geometry. As an application we compute holographically one- and two-point functions of the BFSS matrix quantum mechanics and its supersymmetric $SO(3)\\times SO(6)$ deformation.

  16. Constructing the matrix

    Science.gov (United States)

    Elliott, John

    2012-09-01

    As part of our 'toolkit' for analysing an extraterrestrial signal, the facility for calculating structural affinity to known phenomena must be part of our core capabilities. Without such a resource, we risk compromising our potential for detection and decipherment or at least causing significant delay in the process. To create such a repository for assessing structural affinity, all known systems (language parameters) need to be structurally analysed to 'place' their 'system' within a relational communication matrix. This will need to include all known variants of language structure, whether 'living' (in current use) or ancient; this must also include endeavours to incorporate yet undeciphered scripts and non-human communication, to provide as complete a picture as possible. In creating such a relational matrix, post-detection decipherment will be assisted by a structural 'map' that will have the potential for 'placing' an alien communication with its nearest known 'neighbour', to assist subsequent categorisation of basic parameters as a precursor to decipherment. 'Universal' attributes and behavioural characteristics of known communication structure will form a range of templates (Elliott, 2001 [1] and Elliott et al., 2002 [2]), to support and optimise our attempt at categorising and deciphering the content of an extraterrestrial signal. Detection of the hierarchical layers, which comprise intelligent, complex communication, will then form a matrix of calculations that will ultimately score affinity through a relational matrix of structural comparison. In this paper we develop the rationales and demonstrate functionality with initial test results.

  17. Evaluation of dried blood spots as sample matrix for gas chromatography/mass spectrometry based metabolomic profiling.

    Science.gov (United States)

    Kong, Sing Teang; Lin, Hai-Shu; Ching, Jianhong; Ho, Paul C

    2011-06-01

    We propose using dried blood spots (DBS) as sample matrix for gas chromatography/mass spectrometry (GC/MS) based metabolomic profiling for the benefits of higher sample stability, more convenient sample acquisition with DBS, higher analyte separation power, and more readily biomarker identification with GC/MS. To establish this proposition, the metabolomic profiles generated from DBS were compared with that obtained from the conventional whole blood and plasma matrixes and also with dried plasma spots (DPS) as another covariate control. Our findings indicated that whole blood produced the most number of detectable markers (866), whereas DPS yielded the least number (614). DBS and plasma matrix, on the other hand, produced the most similar numbers of detectable (695 vs 749) and identifiable markers (137 vs 147, matching with Fiehn library). From the analysis of the DBS and plasma metabolomic profiles, it was concluded that when l-lysine 2, iminodiacetic acid 2, dl-threo-beta-hydroxyaspartic acid, citric acid, or adenosine-5-monophosphate 2 are not involved as markers, DBS could be a suitable substitute for plasma for metabolomic profiling.

  18. Generalized Framework for Similarity Measure of Time Series

    Directory of Open Access Journals (Sweden)

    Hongsheng Yin

    2014-01-01

    Full Text Available Currently, there is no definitive and uniform description for the similarity of time series, which results in difficulties for relevant research on this topic. In this paper, we propose a generalized framework to measure the similarity of time series. In this generalized framework, whether the time series is univariable or multivariable, and linear transformed or nonlinear transformed, the similarity of time series is uniformly defined using norms of vectors or matrices. The definitions of the similarity of time series in the original space and the transformed space are proved to be equivalent. Furthermore, we also extend the theory on similarity of univariable time series to multivariable time series. We present some experimental results on published time series datasets tested with the proposed similarity measure function of time series. Through the proofs and experiments, it can be claimed that the similarity measure functions of linear multivariable time series based on the norm distance of covariance matrix and nonlinear multivariable time series based on kernel function are reasonable and practical.

  19. Research on the Connection Bias of Amino Acids Based on Probability Transition Matrix%基于概率转移矩阵的氨基酸连接偏好性研究

    Institute of Scientific and Technical Information of China (English)

    张堃; 唐旭清

    2012-01-01

    在Markov模型的基础上,提出了状态空间上合并映射的概念,以及合并过程下转移概率的计算方法.在已有氨基酸分类方法的基础上,结合Markov模型的概率转移矩阵,对氨基酸连接的偏好性进行了研究.结果表明:同一家族的蛋白质序列的氨基酸连接具有一定的偏好性,这种偏好性与氨基酸的分类有关,从而进一步说明了分类的科学性,同时这种偏好性对氨基酸序列的预测具有一定的作用.%In this manuscript, a novel concept of lumping map and a computing method of the transition probability in lumped process were suggested based on Markov model, to investigate the connection bias of amino acids. The results demonstrated that the connection of amino acids had a particular preference which was related to the classification of amino acids, and further verified the scientific of the classification of amino acids. At the same time, the preference would give some help for the prediction of amino acids sequence.

  20. Ostwald ripening of the matrix phase surrounding dispersoids

    International Nuclear Information System (INIS)

    Self-similar coarsening of particles dispersed in a matrix is well known experimentally and theoretically as Ostwald ripening. In this paper we present experimental and numerical material on Cu-Co dispersions looking for the inverse effect: Does the copper matrix surrounding cobalt particles also coarsen self-similar during liquid phase sintering as the particles do? The experimental investigations were performed with Cu-Co alloys of various volume fractions of solid phase (0.25 to 0.7). Green compacts of both elemental powders were sintered at 1473 K for times between 5 minutes and 70 hours. The coarsening of the matrix was analysed in plane section of the specimens. The experimental results show that the matrix coarsens self-similar. A numerical modelling is presented clarifying the experimental results. (orig.)

  1. XRF matrix corrections

    International Nuclear Information System (INIS)

    Full text: In order to obtain meaningful analytical information from an X-Ray Fluorescence spectrometer, it is necessary to correlate measured intensity values with sample concentrations. The ability to do this to a desired level of precision depends on taking care of a number of variables which influence measured intensity values. These variables include: the sample, which needs to be homogeneous, flat and critically thick to the analyte lines used for measurement; the spectrometer, which needs to perform any mechanical movements in a highly reproducible manner; the time taken to measure an analyte line, and the software, which needs to take care of detector dead-time, the contribution of background to the measured signal, the effects of line overlaps and matrix (absorption and enhancement) effects. This presentation will address commonly used correction procedures for matrix effects and their relative success in achieving their objective. Copyright (2002) Australian X-ray Analytical Association Inc

  2. A nonsupersymmetric matrix orbifold

    CERN Document Server

    Banks, T; Banks, Tom; Motl, Lubos

    2000-01-01

    We construct the matrix description for a twisted version of the IIA string theory on S^1 with fermions antiperiodic around a spatial circle. The result is a 2+1-dimensional U(N) x U(N) nonsupersymmetric Yang-Mills theory with fermionic matter transforming in the (N,Nbar). The two U(N)'s are exchanged if one goes around a twisted circle of the worldvolume. Relations with Type 0 theories are explored and we find Type 0 matrix string limits of our gauge theory. We argue however that most of these results are falsified by the absence of SUSY nonrenormalization theorems and that the models do not in fact have a sensible Lorentz invariant space time interpretation.

  3. 图的无号Laplace矩阵的最大特征值%On the Largest Eigenvalue of Signless Laplacian Matrix of a Graph

    Institute of Scientific and Technical Information of China (English)

    谭尚旺; 王兴科

    2009-01-01

    The signless Laplacian matrix of a graph is the sum of its diagonal matrix of vertex degrees and its adjacency matrix. Li and Feng gave some basic results on the largest eigenvalue and characteristic polynomial of adjacency matrix of a graph in 1979. In this paper, we translate these results into the signless Laplacian matrix of a graph and obtain the similar results.

  4. Inside the NIKE matrix

    OpenAIRE

    BRENNER, BARBARA; Bodo B. Schlegelmilch; Ambos, Björn

    2013-01-01

    This case describes how Nike, a consumer goods company with an ever expanding portfolio and a tremendous brand value, manages the tradeoff between local responsiveness and global integration. In particular, the case highlights Nike's organizational structure that consists of a global matrix organization that is replicated at a regional level for the European market. While this organizational structure allows Nike to respond to local consumer tastes it also ensures that the company benefits f...

  5. 导入透明质酸猪脱细胞真皮基质的刺激性及致敏性研究%Skin irritation and sensitization of swine acellular dermal matrix treated with hyaluronic acid

    Institute of Scientific and Technical Information of China (English)

    宁少南; 赵筱卓; 王慧英; 张国安

    2012-01-01

    Objective To evaluate the skin irritation and sensitization potential of the swine acellular dermal matrix treated with hyaluronic acid (SADM-HA).Methods (1) Skin irritation test.Twelve New Zealand rabbits were divided into SADM-HA group,allogeneic skin group,and (human) xeno-skin group according to the random number table,with 4 rabbits in each group.Four test sites were designed on the back of each rabbit.Two test sites of each rabbit in the three groups were covered with SADM-HA,allogeneic skin,and xeno-skin,respectively.Another test site was covered with gauze containing 200 g/L sodium dodecyl sulfate solution as positive control.The last test site was covered with gauze containing normal saline as negative control.The primary irritation index and cumulative irritation index of each material were calculated.(2) Skin closed-patch test.Sixty guinea pigs were used.Fifty-four guinea pigs were divided into SADM-HA group,allogeneic skin group,and (human) xeno-skin group according to the random number table,with 18 guinea pigs in each group.Twelve guinea pigs in each of the three groups were correspondingly induced and stimulated by SADM-HA,allogeneic skin,and xeno-skin,with 6 guinea pigs in each group treated with ethanol-soaked gauze to serve as negative control.The remaining 6 guinea pigs were treated with gauze containing 25% α-hexylcinnamaldehyde ethanol solution as positive control.The rating scales of Magnusson and Kligman were used to grade the condition of skin after being treated with above-mentioned materials to evaluate skin sensitivity to them at post stimulation hour 24 and 48.Data were processed with the nonparametric test of independent samples.Results (1) In the skin irritation test,the primary irritation indexes of the three dressings in SADM-HA group,allogeneic skin group,and xeno-skin group were respectively-0.04,0.13,and 0.08.The cumulative irritation indexes of the three dressings in SADM-HA group,allogeneic skin group,and xeno-skin group were

  6. Metal matrix Composites

    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.

  7. NMR Structure of the Myristylated Feline Immunodeficiency Virus Matrix Protein

    Directory of Open Access Journals (Sweden)

    Lola A. Brown

    2015-04-01

    Full Text Available Membrane targeting by the Gag proteins of the human immunodeficiency viruses (HIV types-1 and -2 is mediated by Gag’s N-terminally myristylated matrix (MA domain and is dependent on cellular phosphatidylinositol-4,5-bisphosphate [PI(4,5P2]. To determine if other lentiviruses employ a similar membrane targeting mechanism, we initiated studies of the feline immunodeficiency virus (FIV, a widespread feline pathogen with potential utility for development of human therapeutics. Bacterial co-translational myristylation was facilitated by mutation of two amino acids near the amino-terminus of the protein (Q5A/G6S; myrMAQ5A/G6S. These substitutions did not affect virus assembly or release from transfected cells. NMR studies revealed that the myristyl group is buried within a hydrophobic pocket in a manner that is structurally similar to that observed for the myristylated HIV-1 protein. Comparisons with a recent crystal structure of the unmyristylated FIV protein [myr(-MA] indicate that only small changes in helix orientation are required to accommodate the sequestered myr group. Depletion of PI(4,5P2 from the plasma membrane of FIV-infected CRFK cells inhibited production of FIV particles, indicating that, like HIV, FIV hijacks the PI(4,5P2 cellular signaling system to direct intracellular Gag trafficking during virus assembly.

  8. Risk evaluation with enhaced covariance matrix

    CERN Document Server

    Urbanowicz, K; Richmond, P; Holyst, Janusz A.; Richmond, Peter; Urbanowicz, Krzysztof

    2006-01-01

    We propose a route for the evaluation of risk based on a transformation of the covariance matrix. The approach uses a `potential' or `objective' function. This allows us to rescale data from diferent assets (or sources) such that each set then has similar statistical properties in terms of their probability distributions. The method is tested using historical data from both the New York and Warsaw Stock Exchanges.

  9. Dependency Similarity, Attraction and Perceived Happiness.

    Science.gov (United States)

    Pandey, Janak

    1978-01-01

    Subjects were asked to evaluate either a similar personality or a dissimilar personality. Subjects rated similar others more positively than dissimilar others and, additionally, perceived similar others as more helpful and sympathetic than dissimilar others. (Author)

  10. The conserved domain CR2 of Epstein-Barr virus nuclear antigen leader protein is responsible not only for nuclear matrix association but also for nuclear localization.

    Science.gov (United States)

    Yokoyama, A; Kawaguchi, Y; Kitabayashi, I; Ohki, M; Hirai, K

    2001-01-20

    There is a growing body of evidence for the importance of the nuclear matrix in various nuclear events including gene expression and DNA replication. Epstein-Barr virus (EBV) nuclear antigen leader protein (EBNA-LP) is a nuclear matrix-associated protein that has been suggested to play an important role in EBV-induced transformation. To define the biological significance of the association of EBNA-LP with the nuclear matrix, we mapped the domain of EBNA-LP responsible for nuclear matrix association and investigated the functions of the EBNA-LP mutant mutagenized by substitution of alanines for the cluster of arginine residues in the mapped region. The results of the present study were as follows. (i) Transiently expressed EBNA-LP in COS-7 or BOSC23 cells was associated with the nuclear matrix, similarly to that in EBV-infected B cells. (ii) Mutational analysis of EBNA-LP revealed that a 10-amino acid segment of EBNA-LP is critical for nuclear matrix association of the protein. Interestingly, the identified region overlapped with the region CR2 of EBNA-LP conserved among a subset of primate gammaherpesviruses. The identified segment is referred to as EBNA-LP NMTS (nuclear matrix targeting signal). (iii) The EBNA-LP mutant with the arginine to alanine substitutions in NMTS was no longer localized not only to the nuclear matrix but also to the nucleus. (iv) The EBNA-LP mutant lacked its ability to coactivate EBNA-2-dependent transactivation. These results indicated that EBNA-LP needs to be localized in the nucleus and/or associated with the nuclear matrix through CR2 to elicit its function such as the coactivation of the EBNA-2-dependent transcriptional activation. PMID:11162796

  11. Marriage Matters Spousal Similarity in Life Satisfaction

    OpenAIRE

    Schimmack, Ulrich; Richard E. Lucas

    2006-01-01

    Examined the concurrent and cross-lagged spousal similarity in life satisfaction over a 21-year period. Analyses were based on married couples (N = 847) in the German Socio-Economic Panel (SOEP). Concurrent spousal similarity was considerably higher than one-year retest similarity, revealing spousal similarity in the variable component of life satisfac-tion. Spousal similarity systematically decreased with length of retest interval, revealing simi-larity in the changing component of life sati...

  12. 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.

  13. Streptococcus mutans-derived extracellular matrix in cariogenic oral biofilms

    OpenAIRE

    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...

  14. Streptococcus mutans-derived extracellular matrix in cariogenic oral biofilms

    OpenAIRE

    Marlise eKlein; Geelsu eHwang; Paulo eSantos; Osvaldo eCampanella; Hyun eKoo

    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....

  15. Versatile matrix for constructing enzyme-based biosensors.

    Science.gov (United States)

    Wang, Zhaohao; Luo, Xi; Wan, Qijin; Wu, Kangbing; Yang, Nianjun

    2014-10-01

    A versatile matrix was fabricated and utilized as a universal interface for the construction of enzyme-based biosensors. This matrix was formed on the gold electrode via combining self-assembled monolayer of 2,3-dimercaptosuccinic acid with gold nanoparticles. Gold nanoparticles were electrochemically deposited. Electrochemistry of three redox enzymes (catalase, glucose oxidase, and horseradish peroxidase) was investigated on such a matrix. The electrocatalytic monitoring of hydrogen peroxide and glucose was conducted on this matrix after being coated with those enzymes. On them the monitoring of hydrogen peroxide and glucose shows rapid response times, wide linear working ranges, low detection limits, and high enzymatic affinities. This matrix is thus a versatile and suitable platform to develop highly sensitive enzyme-based biosensors. PMID:25208242

  16. 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.

  17. Safety and efficacy findings from a non-interventional study of a new hyaluronic acid/sorbitol formulation (GO-ON® matrix) for intra-articular injection to relieve pain and disability in osteoarthritis patients.

    Science.gov (United States)

    Heisel, J; Kipshoven, C

    2013-09-01

    This non-interventional study was intended to examine the efficacy and tolerability of intra-articular injections with the GO-ON® matrix, a new viscosupplement product made of non-animal sodium hyaluronate combined with the oxygen free radical scavenger sorbitol, when used in routine clinical practice. A total of 1 147 patients (43.5% male, 53,5% female, 3% missing) aged on average 63.3 years with osteoarthritis were enrolled in 398 centers and treated with the product. The most commonly treated joint was the knee (92.9%) with a Kellgren-Lawrence classification of Grade I (6.7%), Grade II (31.4%), Grade III (48.0%), and Grade IV (13.9%).Most patients (58-66%, imputing for missing data) received 1 injection, 29-40% received 3 injections. Using a Likert scale to asses pain, the mean change in pain due to osteoarthritis was a reduction of 56.5% from baseline (2.61±0.80) to 6 months (1.07±0.86). At baseline, 56.2% of patients reported severe/very severe pain versus 5.9% after 6 months. Accordingly, 6.8% of patients reported no pain/mild pain at baseline vs. 67.1% after 6 months. At baseline, 28.9% reported no pain/mild pain vs. to 66.4% after 6 months. At baseline, 29.1% of patients reported severe/very severe functional impairment vs. 3.9% 6 months after the first injection. The 3 and 6 month results were comparable.Adverse reactions were rare and confined to musculoskeletal and connective tissue disorders. No infections were reported in any treated joints. The results confirm that the GO-ON matrix® treatment is effective and well tolerated in the treatment of symptoms due to osteoarthritis.

  18. Nanomedicine I: In vitro and in vivo evaluation of paclitaxel loaded poly-(ε-caprolactone), poly (DL-lactide-co-glycolide) and poly (DL-lactic acid) matrix nanoparticles in wistar rats.

    Science.gov (United States)

    VasanthaKumar, Sekar; Ahamed, Haja Nazeer; Saha, Ranendra N

    2015-06-01

    Progress in nanoscience and nanotechnology laid foundation for nanotherapy-based approach in cancer drug delivery for improved therapy and quality of life. The prepared polymeric nanoparticles (PNPs), PCL, PLGA and PLA NPs help in delivering paclitaxel (TAX) in vivo by avoiding the use of unsafe excipient, Cremophore EL. The classy microscopic examination SEM, TEM and AFM analysis revealed the spherical and smooth structure of the NPs as well as their homogeneous solid matrix without any amorphous arrangements. The FTIR analysis of PNPs exposed that there was no chemical interaction between polymer, stabilizer and TAX. The (1)H NMR and XRD analyses illustrate molecular dispersion of TAX in the polymeric matrix and no evidence was observed for the presence of crystalline TAX. The outcome of in vivo acute toxicity study endorses residual solvent free PNPs. The PNPs demonstrate excellent control in delivering TAX up to 48 h with best fitted to First-order, Baker-Lonsdale, Higuchi and Korsmeyer-Peppas model. The log plasma concentration-time profile shows that the prepared PNPs were safe and have much less side-effects. The pharmacokinetic study results illustrate increase in mean residence time as result of long circulating nature of the prepared nanoparticles, which helps them to reach target area. The estimated pharmacokinetic parameters AUC0-∞ (ng h)/mL, AUMC0-∞ (ng h(2))/mL, C max (ng/mL), t 1/2 (h), MRT (h), Cl (L/h/kg), V ss (L/kg) and V z (L/kg) shows improved therapeutic efficacy when compared with TAX solution. PMID:24671895

  19. The cellulose resource matrix.

    Science.gov (United States)

    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

  20. The cellulose resource matrix.

    Science.gov (United States)

    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

  1. Chromatographic fingerprint similarity analysis for pollutant source identification.

    Science.gov (United States)

    Xie, Juan-Ping; Ni, Hong-Gang

    2015-12-01

    In the present study, a similarity analysis method was proposed to evaluate the source-sink relationships among environmental media for polybrominated diphenyl ethers (PBDEs), which were taken as the representative contaminants. Chromatographic fingerprint analysis has been widely used in the fields of natural products chemistry and forensic chemistry, but its application to environmental science has been limited. We established a library of various sources of media containing contaminants (e.g., plastics), recognizing that the establishment of a more comprehensive library allows for a better understanding of the sources of contamination. We then compared an environmental complex mixture (e.g., sediment, soil) with the profiles in the library. These comparisons could be used as the first step in source tracking. The cosine similarities between plastic and soil or sediment ranged from 0.53 to 0.68, suggesting that plastic in electronic waste is an important source of PBDEs in the environment, but it is not the only source. A similarity analysis between soil and sediment indicated that they have a source-sink relationship. Generally, the similarity analysis method can encompass more relevant information of complex mixtures in the environment than a profile-based approach that only focuses on target pollutants. There is an inherent advantage to creating a data matrix containing all peaks and their relative levels after matching the peaks based on retention times and peak areas. This data matrix can be used for source identification via a similarity analysis without quantitative or qualitative analysis of all chemicals in a sample.

  2. Matrix vector analysis

    CERN Document Server

    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

  3. Matrix string partition function

    CERN Document Server

    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.

  4. Matrix algebra for linear models

    CERN Document Server

    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

  5. Critical points of DNA quantification by real-time PCR – effects of DNA extraction method and sample matrix on quantification of genetically modified organisms

    Directory of Open Access Journals (Sweden)

    Žel Jana

    2006-08-01

    Full Text Available Abstract Background Real-time PCR is the technique of choice for nucleic acid quantification. In the field of detection of genetically modified organisms (GMOs quantification of biotech products may be required to fulfil legislative requirements. However, successful quantification depends crucially on the quality of the sample DNA analyzed. Methods for GMO detection are generally validated on certified reference materials that are in the form of powdered grain material, while detection in routine laboratories must be performed on a wide variety of sample matrixes. Due to food processing, the DNA in sample matrixes can be present in low amounts and also degraded. In addition, molecules of plant origin or from other sources that affect PCR amplification of samples will influence the reliability of the quantification. Further, the wide variety of sample matrixes presents a challenge for detection laboratories. The extraction method must ensure high yield and quality of the DNA obtained and must be carefully selected, since even components of DNA extraction solutions can influence PCR reactions. GMO quantification is based on a standard curve, therefore similarity of PCR efficiency for the sample and standard reference material is a prerequisite for exact quantification. Little information on the performance of real-time PCR on samples of different matrixes is available. Results Five commonly used DNA extraction techniques were compared and their suitability for quantitative analysis was assessed. The effect of sample matrix on nucleic acid quantification was assessed by comparing 4 maize and 4 soybean matrixes. In addition 205 maize and soybean samples from routine analysis were analyzed for PCR efficiency to assess variability of PCR performance within each sample matrix. Together with the amount of DNA needed for reliable quantification, PCR efficiency is the crucial parameter determining the reliability of quantitative results, therefore it was

  6. Matricial bridges for "Matrix algebras converge to the sphere"

    CERN Document Server

    Rieffel, Marc A

    2015-01-01

    In the high-energy quantum-physics literature one finds statements such as "matrix algebras converge to the sphere". Earlier I provided a general setting for understanding such statements, in which the matrix algebras are viewed as quantum metric spaces, and convergence is with respect to a quantum Gromov-Hausdorff-type distance. In the present paper, as preparation of discussing similar statements for convergence of "vector bundles" over matrix algebras to vector bundles over spaces, we introduce and study suitable matrix-norms for matrix algebras and spaces. Very recently Latremoliere introduced an improved quantum Gromov-Hausdorff-type distance between quantum metric spaces. We use it throughout this paper. To facilitate the calculations we introduce and develop a general notion of "bridges with conditional expectations".

  7. Novel additives for the separation of organic acids by ion-pair chromatography

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    This paper proposes the use of novel surfactant additives for the separation of organic acids by ion-pair chromatography and studies the influences of surfactants on the chromatographic separation behaviors.Researches have been carried out on both silica gel matrix and polymer supporters in order to compare the two ordinary kinds of stationary phases,and the phenomenon is similar. Separation is based on differences in the stabilities of analyte-additive complexes in solution.Retention times of analytes c...

  8. Synthesis and Characterization of Long-Chain Tartaric Acid Diamides as Novel Ceramide-Like Compounds

    Directory of Open Access Journals (Sweden)

    Krisztina Takács-Novák

    2010-02-01

    Full Text Available Ceramides play a crucial role in the barrier function of the skin as well as in transmembrane signaling. In this study long aliphatic chain tartaric acid diamides able to replace ceramides in an in vitro model of the stratum corneum lipid matrix due to their similar physico-chemical properties were synthesized from diacetoxysuccinic anhydride in four steps. Their pro-apoptotic effect on fibroblast cells was also investigated.

  9. Determination of precious metals in ceramic matrix

    International Nuclear Information System (INIS)

    Complete text of publication follows. The recycling of the platinum group metals (PGM) especially from spent automobile catalytic converters increases steadily in importance, due to growing demand for, and exhausted resources of, PGM. The use of expensive PGM in catalyst production has fostered the development of an accurate method of determination of PGM in spent catalysts. Catalyst sample preparation by microwave extraction with acids (instead of successful but complex fire assay to recover the PGM from the interfering matrix) was attempted to avoid the spectral interferences resulting of matrix components during ICP-OES analysis. Different spent catalyst samples based mainly on AlO3 and SiO2 containing Pt and Pd were analysed by ICP-OES and, for comparison, ICP-MS to check if the extraction was complete. The components of the matrix of catalyst samples were identified with EDXRF. Several intense emission lines for Pt, Pd and Rh were selected for the detailed investigation of the samples. The measurement method was adjusted in several steps as external standard calibration, bracketing method and standard addition. The optimized measurement method of ICP-OES was applied to BAM reference material of spent automotive catalysts with cordierite basis. Due to many spectral interferences from the sample matrix it is not possible to determine precisely the PGM in automotive catalysts without extracting from the matrix. Microwave extraction is not as effective as fire assay, but provides fast analysis for less demanding applications. The authors gratefully acknowledge the support by Norddeutsche Affinerie and BAM, which provided the samples used in this work.

  10. Induced Elastic Matrix Deposition Within Three-Dimensional Collagen Scaffolds

    OpenAIRE

    Venkataraman, Lavanya; Ramamurthi, Anand

    2011-01-01

    The structural stability of a cyclically distending elastic artery and the healthy functioning of vascular smooth muscle cells (SMCs) within are maintained by the presence of an intact elastic matrix and its principal protein, elastin. The accelerated degradation of the elastic matrix, which occurs in several vascular diseases, coupled with the poor ability of adult SMCs to regenerate lost elastin, can therefore adversely impact vascular homeostasis. Similarly, efforts to tissue engineer elas...

  11. Light cone matrix product

    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.

  12. Matrix Graph Grammars

    CERN Document Server

    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.

  13. Hyaluronan: A Matrix Component

    Science.gov (United States)

    Rügheimer, Louise

    2008-09-01

    The glucosaminoglycan hyaluronan is a key component of the extracellular matrix. It is a large, negatively charged molecule that can act as an ion exchange reservoir for positive ions. Hyaluronan is involved in renomedullary water handling through its water-binding capacity. In the renal medulla, the main source for hyaluronan production is the renomedullary interstitial cells. Hyaluronan synthases are found in the inner part of the plasma membrane and polymerize hyaluronan chains which are extruded into the extracellular space. Hyaluronidases are a family of enzymes involved in the degradation of hyaluronan. They have a wide range of properties, including differences in size, inhibitor sensitivities, catalytic mechanisms, substrate specificities and pH optima.

  14. Matrix Quantization of Turbulence

    CERN Document Server

    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.

  15. Atomic resolution structure of Moloney murine leukemia virus matrix protein and its relationship to other retroviral matrix proteins.

    Science.gov (United States)

    Riffel, Nico; Harlos, Karl; Iourin, Oleg; Rao, Zihe; Kingsman, Alan; Stuart, David; Fry, Elizabeth

    2002-12-01

    Matrix proteins associated with the viral membrane are important in the formation of the viral particle and in virus maturation. The 1.0 A crystal structure of the ecotropic Gammaretrovirus Moloney murine leukemia virus (M-MuLV) matrix protein reveals the conserved topology of other retroviral matrix proteins, despite undetectable sequence similarity. The N terminus (normally myristylated) is exposed and adjacent to a basic surface patch, features likely to contribute to membrane binding. The four proteins in the asymmetric unit make varied contacts. The M-MuLV matrix structure is intermediate, between those of the lentiviruses and other retroviruses. The protein fold appears to be maintained, in part, by the conservation of side chain packing, which may provide a useful tool for searching for weak distant similarities in proteins. PMID:12467570

  16. Asthma and COPD: Differences and Similarities

    Science.gov (United States)

    ... and COPD: differences and similarities Share | Asthma and COPD: Differences and Similarities This article has been reviewed ... or you could have Chronic Obstructive Pulmonary Disease (COPD) , such as emphysema or chronic bronchitis. Because asthma ...

  17. 2-Hydrazinoquinoline: a reactive matrix for matrix-assisted laser desorption/ionization mass spectrometry to detect gaseous carbonyl compounds.

    Science.gov (United States)

    Shigeri, Yasushi; Kamimura, Takuya; Ando, Masanori; Uegaki, Koichi; Sato, Hiroaki; Tani, Fumito; Arakawa, Ryuichi; Kinumi, Tomoya

    2016-01-01

    The sensitivity, range of applications, and reaction mechanism of 2-hydrazinoquinoline as a reactive matrix for matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) were examined. Using a reaction chamber (125L) equipped with a stirring fan and a window for moving the MALDI-MS plate and volatile samples in and out, the sensitivities of 2-hydrazinoquinoline to gaseous aldehydes (formaldehyde, acetaldehyde, propionaldehyde, and n-butyraldehyde) and ketones (acetone, methyl ethyl ketone, and methyl isobutyl ketone) were determined to be at least parts per million (ppm) levels. On the other hand, carboxylic acids (formic acid, acetic acid, propionic acid, and butyric acid) and esters (ethyl acetate, pentyl acetate, isoamyl acetate, and methyl salicylate) could not be detected by 2-hydrazinoquinoline in MALDI-MS. In addition to 2,4-dinitrophenylhydrazine, a common derivatization reagent for analyzing carbonyl compounds quantitatively in gas chromatography and liquid chromatography, the dissolution of 2-hydrazinoquinoline in an acidic solution, such as trifluoroacetic acid, was essential for its function as a reactive matrix for MALDI- MS. PMID:27419901

  18. Learning Good Edit Similarities with Generalization Guarantees

    OpenAIRE

    Bellet, Aurélien; Habrard, Amaury; Sebban, Marc

    2011-01-01

    Similarity and distance functions are essential to many learning algorithms, thus training them has attracted a lot of interest. When it comes to dealing with structured data (e.g., strings or trees), edit similarities are widely used, and there exists a few methods for learning them. However, these methods offer no theoretical guarantee as to the generalization performance and discriminative power of the resulting similarities. Recently, a theory of learning with good similarity functions wa...

  19. Shape Similarity Measures of Linear Entities

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The essential of feature matching technology lies in how to measure the similarity of spatial entities.Among all the possible similarity measures,the shape similarity measure is one of the most important measures because it is easy to collect the necessary parameters and it is also well matched with the human intuition.In this paper a new shape similarity measure of linear entities based on the differences of direction change along each line is presented and its effectiveness is illustrated.

  20. Representation Independent Proximity and Similarity Search

    OpenAIRE

    Chodpathumwan, Yodsawalai; Aleyasin, Amirhossein; Termehchy, Arash; Sun, Yizhou

    2015-01-01

    Finding similar or strongly related entities in a graph database is a fundamental problem in data management and analytics with applications in similarity query processing, entity resolution, and pattern matching. Similarity search algorithms usually leverage the structural properties of the data graph to quantify the degree of similarity or relevance between entities. Nevertheless, the same information can be represented in many different structures and the structural properties observed ove...

  1. Spherical membranes in Matrix theory

    CERN Document Server

    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.

  2. Random matrix models for phase diagrams

    CERN Document Server

    Vanderheyden, Benoit

    2011-01-01

    We describe a random matrix approach that can provide generic and readily soluble mean-field descriptions of the phase diagram for a variety of systems ranging from QCD to high-T_c materials. Instead of working from specific models, phase diagrams are constructed by averaging over the ensemble of theories that possesses the relevant symmetries of the problem. Although approximate in nature, this approach has a number of advantages. First, it can be useful in distinguishing generic features from model-dependent details. Second, it can help in understanding the `minimal' number of symmetry constraints required to reproduce specific phase structures. Third, the robustness of predictions can be checked with respect to variations in the detailed description of the interactions. Finally, near critical points, random matrix models bear strong similarities to Ginsburg-Landau theories with the advantage of additional constraints inherited from the symmetries of the underlying interaction. These constraints can be help...

  3. Algebraic matrix equations in two unknowns

    CERN Document Server

    Bourgeois, Gerald

    2011-01-01

    Let r1,r2,s1,s2 be integers such that gcd(r1,r2)=1 and gcd(s1,s2)=1. We solve the matrix equation A^{r1}B^{s1}A^{r2}B^{s2}=+-Identity where A,B are 2,2 complex matrices that have no common eigenvectors. Let p,q be coprime integers such that |p|+|q|>2. We study the matrix equation B^{-1}A^pB=A^q where A,B are n,n complex invertible matrices. We show that such matrices satisfy B^{-1}AB and A commute. We provide a necessary and sufficient condition for similarity of A^p and A^q. We explicitly solve this problem when A has n distinct eigenvalues and in other particular cases.

  4. Linearized supergravity from Matrix theory

    CERN Document Server

    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.

  5. Enhancing an R-matrix

    CERN Document Server

    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.

  6. Matrix elements of unstable states

    CERN Document Server

    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.

  7. Collagen in the spicule organic matrix of the gorgonian Leptogorgia virgulata

    Science.gov (United States)

    Kingsley, R. J.; Tsuzaki, M.; Watabe, N.; Mechanic, G. L.

    1990-01-01

    Decalcification of the calcareous spicules from the gorgonian Leptogorgia virgulata reveals an organic matrix that may be divided into water insoluble and soluble fractions. The insoluble fraction displays characteristics typical of collagen, which is an unusual component of an invertebrate calcium carbonate structure. This matrix fraction exhibits a collagenous amino acid profile and behavior upon SDS-PAGE. Furthermore, the reducible crosslink, dihydroxylysinonorleucine (DHLNL), is detected in this fraction. The composition of the matrix varies seasonally; i.e., the collagenous composition is most prevalent in the summer. These results indicate that the insoluble matrix is a dynamic structure. Potential roles of this matrix in spicule calcification are discussed.

  8. Mechanical performance evaluation of bionanocomposites with polymeric matrix of poly(lactic acid)-PLA and organo clay; Avaliacao do comprtamento mecanico de bionanocompositos com patriz polimerica de poli(acido latico)-PLA e argila organofilica

    Energy Technology Data Exchange (ETDEWEB)

    Cavalcanti, Shirley N.; Melo, Tomas J.A. de; Araujo, Edcleide M.; Oliveira, Akidauana D.A.; Lima, Jessica C.C., E-mail: shirleynobre@gmail.com [Universidade Federal de Campina Grande - UFCG - Dept. de Engenharia de Materiais, Campina Grande, PB (Brazil)

    2011-07-01

    The aim of this study is to evaluate the influence of ethylene/methyl acrylate (EMA) and ethylene/glycidyl methacrylate (E-GMA) copolymers and organoclay on the mechanical properties of polymer PLA-poly (lactic acid), from the system PLA / organoclay. The clay was organophilized with the ionic surfactant praepagem and the mixtures were prepared in a modular twin screw extruder. The behavior of bionanocomposites was evaluated by tensile and impact tests. The results of FTIR and DR-X indicated that the process was efficient organophilization. The mechanical properties showed that the elastic modulus and tensile strength of bionanocomposites obtained decreased compared to PLA. On the other hand there was a gain for resistance to impact, for all systems except for system PLA/OMMT. (author)

  9. Matrix Models and Gravitational Corrections

    CERN Document Server

    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.

  10. A matrix model for WZW

    Science.gov (United States)

    Dorey, Nick; Tong, David; Turner, Carl

    2016-08-01

    We study a U( N) gauged matrix quantum mechanics which, in the large N limit, is closely related to the chiral WZW conformal field theory. This manifests itself in two ways. First, we construct the left-moving Kac-Moody algebra from matrix degrees of freedom. Secondly, we compute the partition function of the matrix model in terms of Schur and Kostka polynomials and show that, in the large N limit, it coincides with the partition function of the WZW model. This same matrix model was recently shown to describe non-Abelian quantum Hall states and the relationship to the WZW model can be understood in this framework.

  11. A Matrix Model for WZW

    CERN Document Server

    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.

  12. Code Similarity on High Level Programs

    CERN Document Server

    Bernal, M Miron; Nazuno, J Figueroa

    2007-01-01

    This paper presents a new approach for code similarity on High Level programs. Our technique is based on Fast Dynamic Time Warping, that builds a warp path or points relation with local restrictions. The source code is represented into Time Series using the operators inside programming languages that makes possible the comparison. This makes possible subsequence detection that represent similar code instructions. In contrast with other code similarity algorithms, we do not make features extraction. The experiments show that two source codes are similar when their respective Time Series are similar.

  13. Streptococcus mutans-derived extracellular matrix in cariogenic oral biofilms.

    Science.gov (United States)

    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. PMID:25763359

  14. 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.

  15. Streptococcus mutans-derived extracellular matrix in cariogenic oral biofilms.

    Science.gov (United States)

    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.

  16. Cholesterol and stigmasterol within a sunflower oil matrix: Thermal degradation and oxysterols formation.

    Science.gov (United States)

    Barriuso, Blanca; Ansorena, Diana; Poyato, Candelaria; Astiasarán, Iciar

    2015-07-01

    The characteristics of the lipid matrix surrounding sterols exert a great influence in their thermal oxidation process. The objective of this work was to assess the oxidation susceptibility of equal amounts of cholesterol and stigmasterol within a sunflower oil lipid matrix (ratio 1:1:200) during heating (180°C, 0-180min). Remaining percentage of sterols was determined and seven sterol oxidation products (SOPs) were analysed for each type of sterol along the heating treatment. Evolution of the fatty acid profile and vitamin E content of the oil was also studied. Overall oxidation status of the model system was assessed by means of Peroxides Value (PV) and TBARS. PV remained constant from 30min onwards and TBARS continued increasing along the whole heating treatment. Degradation of both cholesterol and stigmasterol fitted a first order curve (R(2)=0.937 and 0.883, respectively), with very similar degradation constants (0.004min(-1) and 0.005min(-1), respectively). However, higher concentrations of oxidation products were found from cholesterol (79μg/mg) than from stigmasterol (53μg/mg) at the end of the heating treatment. Profile of individual oxidation products was similar for both sterols, except for the fact that no 25-hydroxystigmasterol was detected. 7α-Hydroxy and 7-keto-derivatives were the most abundant SOPs at the end of the treatment. PUFA and vitamin E suffered a significant degradation along the process, which was correlated to sterols oxidation.

  17. Matrix Product Operators, Matrix Product States, and ab initio Density Matrix Renormalization Group algorithms

    CERN Document Server

    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...

  18. Quantitative analysis of biopolymers by matrix-assisted laser desorption

    Energy Technology Data Exchange (ETDEWEB)

    Tang, K.; Allman, S.L.; Jones, R.B.; Chen, C.H. (Oak Ridge National Lab., TN (United States))

    1993-08-01

    During the past few years, major efforts have been made to use mass spectrometry to measure biopolymers because of the great potential benefit to biological and medical research. Although the theoretical details of laser desorption and ionization mechanisms of MALDI are not yet fully understood, several models have been presented to explain the production of large biopolymer ions. In brief, it is very difficult to obtain reliable measurements of the absolute quantity of analytes by MALDI. If MALDI is going to become a routine analytical tool, it is obvious that quantitative measurement capability must be pursued. Oligonucleotides and protein samples used in this work were purchased from commercial sources. Nicotinic acid was used as matrix for both types of biopolymers. From this experiment, it is seen that it is difficult to obtain absolute quantitative measurements of biopolymers using MALDI. However, internal calibration with molecules having similar chemical properties can be used to resolve these difficulties. Chemical reactions between biopolymers must be avoided to prevent the destruction of the analyte materials. 10 refs., 8 figs.

  19. Extracellular matrix proteins and the dynamics of dentin formation.

    Science.gov (United States)

    Butler, William T; Brunn, Jan C; Qin, Chunlin; McKee, Marc D

    2002-01-01

    Dentinogenesis involves controlled reactions that result in conversion of unmineralized predentin to dentin when apatite crystals are formed. This process is dynamic: Maturation events occur within predentin beginning at the proximal layer and progressing to the predentin-dentin (PD) border. One type of controlled reaction is the proteolytic processing of dentin sialophosphoprotein (DSPP) to dentin sialoprotein (DSP) and dentin phosphoprotein (DPP), by cleavage of at least three highly conserved peptide bonds. We postulate that this processing event represents an activation step, resulting in release of DPP, which is active in its effects on formation and growth of apatite crystals. Dentin matrix protein 1 (DPM1), present as a processed fragment (57-kD protein) in bone, is seen in dentin on sodium dodecyl sulfate polyacrylamide gel electrophoresis as one intact protein of 150-200 kD. Anti-57-kD antibodies elicit immunoreactivity in bone, dentin, and cellular cementum. In bone, the reactivity is associated with osteocytes and their cell processes. Similarly, dentin shows reactivity in odontoblasts, predentin, and the odontoblast processes. In summary, the processing of large sialic acid-rich proteins into smaller fragments may be an important part of the controlled conversion of predentin to dentin and osteoid to bone.

  20. Testing Self-Similarity Through Lamperti Transformations

    KAUST Repository

    Lee, Myoungji

    2016-07-14

    Self-similar processes have been widely used in modeling real-world phenomena occurring in environmetrics, network traffic, image processing, and stock pricing, to name but a few. The estimation of the degree of self-similarity has been studied extensively, while statistical tests for self-similarity are scarce and limited to processes indexed in one dimension. This paper proposes a statistical hypothesis test procedure for self-similarity of a stochastic process indexed in one dimension and multi-self-similarity for a random field indexed in higher dimensions. If self-similarity is not rejected, our test provides a set of estimated self-similarity indexes. The key is to test stationarity of the inverse Lamperti transformations of the process. The inverse Lamperti transformation of a self-similar process is a strongly stationary process, revealing a theoretical connection between the two processes. To demonstrate the capability of our test, we test self-similarity of fractional Brownian motions and sheets, their time deformations and mixtures with Gaussian white noise, and the generalized Cauchy family. We also apply the self-similarity test to real data: annual minimum water levels of the Nile River, network traffic records, and surface heights of food wrappings. © 2016, International Biometric Society.

  1. Biophysical properties of phenyl succinic acid derivatised hyaluronic acid

    DEFF Research Database (Denmark)

    Neves-Petersen, Maria Teresa; Klitgaard, Søren; Skovsen, Esben;

    2010-01-01

    Modification of hyaluronic acid (HA) with aryl succinic anhydrides results in new biomedical properties of HA as compared to non-modified HA, such as more efficient skin penetration, stronger binding to the skin, and the ability to blend with hydrophobic materials. In the present study, hyaluronic...... acid has been derivatised with the anhydride form of phenyl succinic acid (PheSA). The fluorescence of PheSA was efficiently quenched by the HA matrix. HA also acted as a singlet oxygen scavenger. Fluorescence lifetime(s) of PheSA in solution and when attached to the HA matrix has been monitored...

  2. Ceramic matrix composite article and process of fabricating a ceramic matrix composite article

    Science.gov (United States)

    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.

  3. How to Study a Matrix

    Science.gov (United States)

    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…

  4. Matrix Analysis of Tracer Transport

    CERN Document Server

    Mills, Peter

    2015-01-01

    We review matrix methods as applied to tracer transport. Because tracer transport is linear, matrix methods are an ideal fit for the problem. In particular, solutions of linear, first-order systems of ordinary differential equations (ODEs) are reviewed as well as special properties of these solutions. Detailed derivations are included

  5. Matrix-assisted laser desorption/ionization mass spectrometric analysis of aliphatic biodegradable photoluminescent polymers using new ionic liquid matrices.

    Science.gov (United States)

    Serrano, Carlos A; Zhang, Yi; Yang, Jian; Schug, Kevin A

    2011-05-15

    In this study, two novel ionic liquid matrices (ILMs), N,N-diisopropylethylammonium 3-oxocoumarate and N,N-diisopropylethylammonium dihydroxymonooxoacetophenoate, were tested for the structural elucidation of recently developed aliphatic biodegradable polymers by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The polymers, formed by a condensation reaction of three components, citric acid, octane diol, and an amino acid, are fluorescent, but the exact mechanism behind their luminescent properties has not been fully elucidated. In the original studies, which introduced the polymer class (J. Yang et al., Proc. Natl. Acad. Sci. USA 2009, 106, 10086-10091), a hyper-conjugated cyclic structure was proposed as the source for the photoluminescent behavior. With the use of the two new ILMs, we present evidence that supports the presence of the proposed cyclization product. In addition, the new ILMs, when compared with a previously established ILM, N,N-diisopropylethylammonium α-cyano-3-hydroxycinnimate, provided similar signal intensities and maintained similar spectral profiles. This research also established that the new ILMs provided good spot-to-spot reproducibility and high ionization efficiency compared with corresponding crystalline matrix preparations. Many polymer features revealed through the use of the ILMs could not be observed with crystalline matrices. Ultimately, the new ILMs highlighted the composition of the synthetic polymers, as well as the loss of water that was expected for the formation of the proposed cyclic structure on the polymer backbone.

  6. Learning music similarity from relative user ratings

    OpenAIRE

    Wolff, D.; Weyde, T.

    2013-01-01

    Computational modelling of music similarity is an increasingly important part of personalisation and optimisation in music information retrieval and research in music perception and cognition. The use of relative similarity ratings is a new and promising approach to modelling similarity that avoids well known problems with absolute ratings. In this article, we use relative ratings from the MagnaTagATune dataset with new and existing variants of state-of-the-art algorithms and provide the firs...

  7. Molecular quantum similarity using conceptual DFT descriptors

    Indian Academy of Sciences (India)

    Patrick Bultinck; Ramon carbó-dorca

    2005-09-01

    This paper reports a Molecular Quantum Similarity study for a set of congeneric steroid molecules, using as basic similarity descriptors electron density ρ (r), shape function (r), the Fukui functions +(r) and -(r) and local softness +(r) and -(r). Correlations are investigated between similarity indices for each couple of descriptors used and compared to assess whether these different descriptors sample different information and to investigate what information is revealed by each descriptor.

  8. Good edit similarity learning by loss minimization

    OpenAIRE

    Bellet, Aurélien; Habrard, Amaury; Sebban, Marc

    2012-01-01

    Similarity functions are a fundamental component of many learning algorithms. When dealing with string or tree-structured data, edit distancebased measures are widely used, and there exists a few methods for learning them from data. However, these methods offer no theoretical guarantee as to the generalization ability and discriminative power of the learned similarities. In this paper, we propose a loss minimization-based edit similarity learning approach, called GESL. It is driven by the not...

  9. Quadruplet-Wise Image Similarity Learning

    OpenAIRE

    Law M.T.; Thome N.; Cord M.

    2013-01-01

    International audience This paper introduces a novel similarity learning frame-work. Working with inequality constraints involving quadruplets of images, our approach aims at efficiently modeling similarity from rich or complex semantic label relationships. From these quadruplet-wise constraints, we propose a similarity learning framework relying on a con-vex optimization scheme. We then study how our metric learning scheme can exploit specific class relationships, such as class ranking (r...

  10. Secure sketch search for document similarity

    OpenAIRE

    Örencik, Cengiz; Orencik, Cengiz; Alewiwi, Mahmoud Khaled; SAVAŞ, Erkay; Savas, Erkay

    2015-01-01

    Document similarity search is an important problem that has many applications especially in outsourced data. With the wide spread of cloud computing, users tend to outsource their data to remote servers which are not necessarily trusted. This leads to the problem of protecting the privacy of sensitive data. We design and implement two secure similarity search schemes for textual documents utilizing locality sensitive hashing techniques for cosine similarity. While the first one provides very ...

  11. Dark matter halo's and self similarity

    OpenAIRE

    Alard, C.

    2012-01-01

    This papers explores the self similar solutions of the Vlasov-Poisson system and their relation to the gravitational collapse of dynamically cold systems. Analytic solutions are derived for power law potential in one dimension, and extensions of these solutions in three dimensions are proposed. Next the self similarity of the collapse of cold dynamical systems is investigated numerically. The fold system in phase space is consistent with analytic self similar solutions, the solutions present ...

  12. Similarity and a Duality for Fullerenes

    OpenAIRE

    Jennifer J. Edmond; Graver, Jack E.

    2015-01-01

    Fullerenes are molecules of carbon that are modeled by trivalent plane graphs with only pentagonal and hexagonal faces. Scaling up a fullerene gives a notion of similarity, and fullerenes are partitioned into similarity classes. In this expository article, we illustrate how the values of two important fullerene parameters can be deduced for all fullerenes in a similarity class by computing the values of these parameters for just the three smallest representatives of that class. In addition, i...

  13. Efficient Authentication of Outsourced String Similarity Search

    OpenAIRE

    Dong, Boxiang; Wang, Hui

    2016-01-01

    Cloud computing enables the outsourcing of big data analytics, where a third party server is responsible for data storage and processing. In this paper, we consider the outsourcing model that provides string similarity search as the service. In particular, given a similarity search query, the service provider returns all strings from the outsourced dataset that are similar to the query string. A major security concern of the outsourcing paradigm is to authenticate whether the service provider...

  14. Biosequence Similarity Search on the Mercury System

    OpenAIRE

    Krishnamurthy, Praveen; Buhler, Jeremy; Chamberlain, Roger; Franklin, Mark; Gyang, Kwame; Jacob, Arpith; Lancaster, Joseph

    2007-01-01

    Biosequence similarity search is an important application in modern molecular biology. Search algorithms aim to identify sets of sequences whose extensional similarity suggests a common evolutionary origin or function. The most widely used similarity search tool for biosequences is BLAST, a program designed to compare query sequences to a database. Here, we present the design of BLASTN, the version of BLAST that searches DNA sequences, on the Mercury system, an architecture that supports high...

  15. Persistent Homology and Partial Similarity of Shapes

    OpenAIRE

    Di Fabio, Barbara; Landi, Claudia

    2011-01-01

    The ability to perform shape retrieval based not only on full similarity, but also partial similarity is a key property for any content-based search engine. We prove that persistence diagrams can reveal a partial similarity between two shapes by showing a common subset of points. This can be explained using the Mayer-Vietoris formulas that we develop for ordinary, relative and extended persistent homology. An experiment outlines the potential of persistence diagrams as shape descriptors in re...

  16. Mechanisms controlling fatigue damage development in continuous fiber reinforced metal matrix composites

    Science.gov (United States)

    Johnson, W. S.

    1989-01-01

    Damage in continuous fiber reinforced metal matrix composite materials can be quite complex since there are a number of different constituents (fiber, matrix, and the fiber/matrix interface) that can fail. Multidirectional lay-ups have an even greater number of possible damage orientations and mechanisms. Based on the simplifying assumption of equivalent constituent strain states in the absence of damage, a strain based failure criteria may be applied to determine when and where initial damage will occur. Based on the relative strain to fatigue failure of the fiber and matrix, the possible damage mechanisms of an MMC can be grouped into three categories: (1) matrix dominated, (2) fiber dominated, and (3) self-similar damage growth. A fourth type of damage development, fiber/matrix interface failure, is dependent on the relative strength of the fiber/matrix interface and the matrix yield strength. These four types of damage are discussed and illustrated by examples.

  17. Cosmology and the S-matrix

    Energy Technology Data Exchange (ETDEWEB)

    Bousso, Raphael

    2005-01-25

    We study conditions for the existence of asymptotic observables in cosmology. With the exception of de Sitter space, the thermal properties of accelerating universes permit arbitrarily long observations, and guarantee the production of accessible states of arbitrarily large entropy. This suggests that some asymptotic observables may exist, despite the presence of an event horizon. Comparison with decelerating universes shows surprising similarities: Neither type suffers from the limitations encountered in de Sitter space, such as thermalization and boundedness of entropy. However, we argue that no realistic cosmology permits the global observations associated with an S-matrix.

  18. Cluster Tree Based Hybrid Document Similarity Measure

    Directory of Open Access Journals (Sweden)

    M. Varshana Devi

    2015-10-01

    Full Text Available similarity measure is established to measure the hybrid similarity. In cluster tree, the hybrid similarity measure can be calculated for the random data even it may not be the co-occurred and generate different views. Different views of tree can be combined and choose the one which is significant in cost. A method is proposed to combine the multiple views. Multiple views are represented by different distance measures into a single cluster. Comparing the cluster tree based hybrid similarity with the traditional statistical methods it gives the better feasibility for intelligent based search. It helps in improving the dimensionality reduction and semantic analysis.

  19. Machining of Metal Matrix Composites

    CERN Document Server

    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...

  20. Matrix convolution operators on groups

    CERN Document Server

    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.

  1. Multivariate Matrix-Exponential Distributions

    DEFF Research Database (Denmark)

    Bladt, Mogens; Nielsen, Bo Friis

    2010-01-01

    In this article we consider the distributions of non-negative random vectors with a joint rational Laplace transform, i.e., a fraction between two multi-dimensional polynomials. These distributions are in the univariate case known as matrix-exponential distributions, since their densities can be...... written as linear combinations of the elements in the exponential of a matrix. For this reason we shall refer to multivariate distributions with rational Laplace transform as multivariate matrix-exponential distributions (MVME). The marginal distributions of an MVME are univariate matrix......-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 for the...

  2. Two-photon ionization thresholds of matrix-assisted laser desorption/ionization matrix clusters.

    Science.gov (United States)

    Lin, Q; Knochenmuss, R

    2001-01-01

    Direct two-photon ionization of the matrix has been considered a likely primary ionization mechanism in matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. This mechanism requires that the vertical ionization threshold of matrix materials be below twice the laser photon energy. Because dimers and larger aggregates may be numerous in the early stages of the MALDI plume expansion, their ionization thresholds are important as well. We have used two-color two-photon ionization to determine the ionization thresholds of jet cooled clusters of an important matrix, 2,5-dihydroxy benzoic acid (DHB), and mixed clusters with the thermal decomposition product of DHB, hydroquinone. The thresholds of the clusters were reduced by only a few tenths of an eV compared to the monomers, to an apparent limit of 7.82 eV for pure DHB clusters. None of the investigated clusters can be directly ionized by two nitrogen laser photons (7.36 eV), and the ionization efficiency at the thresholds is low. PMID:11507754

  3. On the employment of lambda carrageenan in a matrix system. III. Optimization of a lambda carrageenan-HPMC hydrophilic matrix

    NARCIS (Netherlands)

    Bonferoni, MC; Rossi, S; Ferrari, F; Bertoni, M; Bolhuis, GK; Caramella, C

    1998-01-01

    The lambda carrageenan/HPMC ratio in matrix tablets has been optimized in order to obtain pH-independent release profiles of chlorpheniramine maleate, a freely soluble drug. Release profiles in acidic (pH 1.2) and neutral (pH 6.8) media were fitted according to the Weibull and the power law models.

  4. Florid pustular dermatitis of breast: A case report on a unusual complication from acellular dermal matrix use

    Directory of Open Access Journals (Sweden)

    Justin James

    2016-01-01

    Conclusion: Pustular dermatitis like presentation can be associated with acelluar dermal matrix use and should be considered in similar clinical presentations, since this can avoid unnecessary surgical procedures.

  5. Convex Sparse Matrix Factorizations

    CERN Document Server

    Bach, Francis; Ponce, Jean

    2008-01-01

    We present a convex formulation of dictionary learning for sparse signal decomposition. Convexity is obtained by replacing the usual explicit upper bound on the dictionary size by a convex rank-reducing term similar to the trace norm. In particular, our formulation introduces an explicit trade-off between size and sparsity of the decomposition of rectangular matrices. Using a large set of synthetic examples, we compare the estimation abilities of the convex and non-convex approaches, showing that while the convex formulation has a single local minimum, this may lead in some cases to performance which is inferior to the local minima of the non-convex formulation.

  6. Similarity indices I: what do they measure

    International Nuclear Information System (INIS)

    A method for estimating the effects of environmental effusions on ecosystems is described. The characteristics of 25 similarity indices used in studies of ecological communities were investigated. The type of data structure, to which these indices are frequently applied, was described as consisting of vectors of measurements on attributes (species) observed in a set of samples. A general similarity index was characterized as the result of a two-step process defined on a pair of vectors. In the first step an attribute similarity score is obtained for each attribute by comparing the attribute values observed in the pair of vectors. The result is a vector of attribute similarity scores. These are combined in the second step to arrive at the similarity index. The operation in the first step was characterized as a function, g, defined on pairs of attribute values. The second operation was characterized as a function, F, defined on the vector of attribute similarity scores from the first step. Usually, F was a simple sum or weighted sum of the attribute similarity scores. It is concluded that similarity indices should not be used as the test statistic to discriminate between two ecological communities

  7. Perceived Similarity, Proactive Adjustment, and Organizational Socialization

    Science.gov (United States)

    Kammeyer-Mueller, John D.; Livingston, Beth A.; Liao, Hui

    2011-01-01

    The present study explores how perceived demographic and attitudinal similarity can influence proactive behavior among organizational newcomers. We propose that newcomers who perceive themselves as similar to their co-workers will be more willing to seek new information or build relationships, which in turn will lead to better long-term…

  8. Similarity indices I: what do they measure.

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, J.W.

    1976-11-01

    A method for estimating the effects of environmental effusions on ecosystems is described. The characteristics of 25 similarity indices used in studies of ecological communities were investigated. The type of data structure, to which these indices are frequently applied, was described as consisting of vectors of measurements on attributes (species) observed in a set of samples. A general similarity index was characterized as the result of a two-step process defined on a pair of vectors. In the first step an attribute similarity score is obtained for each attribute by comparing the attribute values observed in the pair of vectors. The result is a vector of attribute similarity scores. These are combined in the second step to arrive at the similarity index. The operation in the first step was characterized as a function, g, defined on pairs of attribute values. The second operation was characterized as a function, F, defined on the vector of attribute similarity scores from the first step. Usually, F was a simple sum or weighted sum of the attribute similarity scores. It is concluded that similarity indices should not be used as the test statistic to discriminate between two ecological communities.

  9. Interleaving Helps Students Distinguish among Similar Concepts

    Science.gov (United States)

    Rohrer, Doug

    2012-01-01

    When students encounter a set of concepts (or terms or principles) that are similar in some way, they often confuse one with another. For instance, they might mistake one word for another word with a similar spelling (e.g., allusion instead of illusion) or choose the wrong strategy for a mathematics problem because it resembles a different kind of…

  10. Similarity Structure of Wave-Collapse

    DEFF Research Database (Denmark)

    Rypdal, Kristoffer; Juul Rasmussen, Jens; Thomsen, Kenneth

    1985-01-01

    Similarity transformations of the cubic Schrödinger equation (CSE) are investigated. The transformations are used to remove the explicit time variation in the CSE and reduce it to differential equations in the spatial variables only. Two different methods for similarity reduction are employed and...

  11. Similarity Measures for Boolean Search Request Formulations.

    Science.gov (United States)

    Radecki, Tadeusz

    1982-01-01

    Proposes a means for determining the similarity between search request formulations in online information retrieval systems, and discusses the use of similarity measures for clustering search formulations and document files in such systems. Experimental results using the proposed methods are presented in three tables. A reference list is provided.…

  12. Outsourced similarity search on metric data assets

    DEFF Research Database (Denmark)

    Yiu, Man Lung; Assent, Ira; Jensen, Christian Søndergaard;

    2012-01-01

    This paper considers a cloud computing setting in which similarity querying of metric data is outsourced to a service provider. The data is to be revealed only to trusted users, not to the service provider or anyone else. Users query the server for the most similar data objects to a query example...

  13. Some Effects of Similarity Self-Disclosure

    Science.gov (United States)

    Murphy, Kevin C.; Strong, Stanley R.

    1972-01-01

    College males were interviewed about how college had altered their friendships, values, and plans. The interviewers diclosed experiences and feelings similar to those revealed by the students. Results support Byrne's Law of Similarity in generating interpersonal attraction in the interview and suggest that the timing of self-disclosures is…

  14. Similar methodological analysis involving the user experience.

    Science.gov (United States)

    Almeida e Silva, Caio Márcio; Okimoto, Maria Lúcia R L; Tanure, Raffaela Leane Zenni

    2012-01-01

    This article deals with the use of a protocol for analysis of similar methodological analysis related to user experience. For both, were selected articles recounting experiments in the area. They were analyze based on the similar analysis protocol and finally, synthesized and associated.

  15. Measure of Node Similarity in Multilayer Networks

    CERN Document Server

    Mollgaard, Anders; Dammeyer, Jesper; Jensen, Mogens H; Lehmann, Sune; Mathiesen, Joachim

    2016-01-01

    The weight of links in a network is often related to the similarity of the nodes. Here, we introduce a simple tunable measure for analysing the similarity of nodes across different link weights. In particular, we use the measure to analyze homophily in a group of 659 freshman students at a large university. Our analysis is based on data obtained using smartphones equipped with custom data collection software, complemented by questionnaire-based data. The network of social contacts is represented as a weighted multilayer network constructed from different channels of telecommunication as well as data on face-to-face contacts. We find that even strongly connected individuals are not more similar with respect to basic personality traits than randomly chosen pairs of individuals. In contrast, several socio-demographics variables have a significant degree of similarity. We further observe that similarity might be present in one layer of the multilayer network and simultaneously be absent in the other layers. For a...

  16. Semantic Similarity Calculation of Chinese Word

    Directory of Open Access Journals (Sweden)

    Liqiang Pan

    2014-08-01

    Full Text Available This paper puts forward a two layers computing method to calculate semantic similarity of Chinese word. Firstly, using Latent Dirichlet Allocation (LDA subject model to generate subject spatial domain. Then mapping word into topic space and forming topic distribution which is used to calculate semantic similarity of word(the first layer computing. Finally, using semantic dictionary "HowNet" to deeply excavate semantic similarity of word (the second layer computing. This method not only overcomes the problem that it’s not specific enough merely using LDA to calculate semantic similarity of word, but also solves the problems such as new words (haven’t been added in dictionary and without considering specific context when calculating semantic similarity based on semantic dictionary "HowNet". By experimental comparison, this thesis proves feasibility,availability and advantages of the calculation method.

  17. Similarity and a Duality for Fullerenes

    Directory of Open Access Journals (Sweden)

    Jennifer J. Edmond

    2015-11-01

    Full Text Available Fullerenes are molecules of carbon that are modeled by trivalent plane graphs with only pentagonal and hexagonal faces. Scaling up a fullerene gives a notion of similarity, and fullerenes are partitioned into similarity classes. In this expository article, we illustrate how the values of two important fullerene parameters can be deduced for all fullerenes in a similarity class by computing the values of these parameters for just the three smallest representatives of that class. In addition, it turns out that there is a natural duality theory for similarity classes of fullerenes based on one of the most important fullerene construction techniques: leapfrog construction. The literature on fullerenes is very extensive, and since this is a general interest journal, we will summarize and illustrate the fundamental results that we will need to develop similarity and this duality.

  18. New beginnings for matrix metalloproteinase inhibitors: identification of high-affinity zinc-binding groups.

    Science.gov (United States)

    Puerta, David T; Lewis, Jana A; Cohen, Seth M

    2004-07-14

    In an effort to identify promising non-hydroxamate inhibitors of matrix metalloproteinases (MMPs), several new zinc-binding groups (ZBGs) based on pyrone, pyrothione, hydroxypyridinone, and hydroxypyridinethione chelators have been examined. Structural studies with tris(pyrazolyl)borate model complexes show that these ligands bind to the MMP active site zinc(II) ion in a bidentate fashion, similar to that found with hydroxamate-based inhibitors. Fluorescence- and colorimetric-based enzyme assays have been used to determine the IC50 values for these ZBGs against MMP-3; mixed O,S-donor ligands were found to be remarkably potent, with IC50 values as much as 700-fold lower than that found for acetohydroxamic acid. Inhibitory activity was found to parallel metal binding affinity as determined in titrations with model complexes. These results demonstrate that MPIs based on new ZBGs are feasible and may indeed improve the overall performance of inhibitors designed against these important medicinal targets. PMID:15237990

  19. The matrix of inspiration

    Science.gov (United States)

    Oehlmann, Dietmar; Ohlmann, Odile M.; Danzebrink, Hans U.

    2005-04-01

    perform this exchange, as a matrix, understood as source, of new ideas.

  20. Containment Code Validation Matrix

    International Nuclear Information System (INIS)

    The Committee on the Safety of Nuclear Installations (CSNI) formed the CCVM (Containment Code Validation Matrix) task group in 2002. The objective of this group was to define a basic set of available experiments for code validation, covering the range of containment (ex-vessel) phenomena expected in the course of light and heavy water reactor design basis accidents and beyond design basis accidents/severe accidents. It was to consider phenomena relevant to pressurised heavy water reactor (PHWR), pressurised water reactor (PWR) and boiling water reactor (BWR) designs of Western origin as well as of Eastern European VVER types. This work would complement the two existing CSNI validation matrices for thermal hydraulic code validation (NEA/CSNI/R(1993)14) and In-vessel core degradation (NEA/CSNI/R(2001)21). The report initially provides a brief overview of the main features of a PWR, BWR, CANDU and VVER reactors. It also provides an overview of the ex-vessel corium retention (core catcher). It then provides a general overview of the accident progression for light water and heavy water reactors. The main focus is to capture most of the phenomena and safety systems employed in these reactor types and to highlight the differences. This CCVM contains a description of 127 phenomena, broken down into 6 categories: - Containment Thermal-hydraulics Phenomena; - Hydrogen Behaviour (Combustion, Mitigation and Generation) Phenomena; - Aerosol and Fission Product Behaviour Phenomena; - Iodine Chemistry Phenomena; - Core Melt Distribution and Behaviour in Containment Phenomena; - Systems Phenomena. A synopsis is provided for each phenomenon, including a description, references for further information, significance for DBA and SA/BDBA and a list of experiments that may be used for code validation. The report identified 213 experiments, broken down into the same six categories (as done for the phenomena). An experiment synopsis is provided for each test. Along with a test description

  1. Self-assembled composite matrix in a hierarchical 3-D scaffold for bone tissue engineering

    DEFF Research Database (Denmark)

    Chen, Muwan; Le, Dang Quang Svend; Baatrup, Anette;

    2011-01-01

    MSC seeding efficiency, proliferation, distribution and differentiation. Porous PCL meshes prepared by fused deposition modeling (FDM) were embedded in matrix of hyaluronic acid, methylated collagen and terpolymer via polyelectrolyte complex coacervation. Scaffolds were cultured statically and dynamically...

  2. 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.

  3. A metal ion charged mixed matrix membrane for selective adsorption of hemoglobin

    NARCIS (Netherlands)

    Tetala, Kishore K.R.; Skrzypek, Katarzyna; Levisson, Mark; Stamatialis, Dimitrios F.

    2013-01-01

    In this work, we developed a mixed matrix membrane by incorporating 20–40 μm size iminodiacetic acid modified immobeads within porous Ethylene vinyl alcohol (EVAL) polymer matrix. The MMM were charged with copper ions for selective adsorption of bovine hemoglobin in presence of bovine serum albumin.

  4. The transfer matrix approach to circular graphene quantum dots

    Science.gov (United States)

    Chau Nguyen, H.; Nguyen, Nhung T. T.; Nguyen, V. Lien

    2016-07-01

    We adapt the transfer matrix (T-matrix) method originally designed for one-dimensional quantum mechanical problems to solve the circularly symmetric two-dimensional problem of graphene quantum dots. Similar to one-dimensional problems, we show that the generalized T-matrix contains rich information about the physical properties of these quantum dots. In particular, it is shown that the spectral equations for bound states as well as quasi-bound states of a circular graphene quantum dot and related quantities such as the local density of states and the scattering coefficients are all expressed exactly in terms of the T-matrix for the radial confinement potential. As an example, we use the developed formalism to analyse physical aspects of a graphene quantum dot induced by a trapezoidal radial potential. Among the obtained results, it is in particular suggested that the thermal fluctuations and electrostatic disorders may appear as an obstacle to controlling the valley polarization of Dirac electrons.

  5. IMP: A Message-Passing Algorithmfor Matrix Completion

    CERN Document Server

    Kim, Byung-Hak; Pfister, Henry D

    2010-01-01

    A new message-passing (MP) method is considered for the matrix completion problem associated with recommender systems. We attack the problem using a (generative) factor graph model that is related to a probabilistic low-rank matrix factorization. Based on the model, we propose a new algorithm, termed IMP, for the recovery of a data matrix from incomplete observations. The algorithm is based on a clustering followed by inference via MP (IMP). The algorithm is compared with a number of other matrix completion algorithms on real collaborative filtering (e.g., Netflix) data matrices. Our results show that, while many methods perform similarly with a large number of revealed entries, the IMP algorithm outperforms all others when the fraction of observed entries is small. This is helpful because it reduces the well-known cold-start problem associated with collaborative filtering (CF) systems in practice.

  6. Network structure of phonographic market with characteristic similarities between musicians

    CERN Document Server

    Buda, Andrzej

    2012-01-01

    We investigate relations between best selling artists in last decade on phonographic market and from perspective of listeners by using the Social Network Analyzes. Starting network is obtained from the matrix of correlations between the world's best selling artists by considering the synchronous time evolution of weekly record sales. This method reveals the structure of phonographic market, but we claim that it has no impact on people who see relationship between artists and music genres. We compare 'sale' (based on correlation of record sales) or 'popularity' (based on data mining of the record charts) networks with 'similarity' (obtained mainly from survey within music experts opinion) and find no significant relations. We postulate that non-laminar phenomena on this specific market introduce turbulence to how people view relations of artists.

  7. Bioreporter pseudomonas fluorescens HK44 immobilized in a silica matrix

    Directory of Open Access Journals (Sweden)

    Trogl J.

    2003-01-01

    Full Text Available The bioluminescent bioreporter Pseudomonas fluorescens HK44, the whole cell bacterial biosensor that responds to naphthalene and its metabolites via the production of visible light, was immobilized into a silica matrix by the sol-gel technique. The bioluminescence intensities were measured in the maximum of the bioluminescence band at X = 500 nm. The immobilized cells (>105 cells per g silica matrix produced light after induction by salicylate (cone. > 10 g/l, naphthalene and aminobenzoic acid. The bioluminescence intensities induced by 2,3-dihydroxynaphthalene 3-hydroxybenzoic acid and 4-hydroxybenzoic acid were comparable to a negative control. The cells in the silica layers on glass slides produced light in response to the presence of an inductor at least 8 months after immobilization, and >50 induction cycles. The results showed that these test slides could be used as assays for the multiple determination of water pollution.

  8. Canonical density matrix perturbation theory.

    Science.gov (United States)

    Niklasson, Anders M N; Cawkwell, M J; Rubensson, Emanuel H; Rudberg, Elias

    2015-12-01

    Density matrix perturbation theory [Niklasson and Challacombe, Phys. Rev. Lett. 92, 193001 (2004)] is generalized to canonical (NVT) free-energy ensembles in tight-binding, Hartree-Fock, or Kohn-Sham density-functional theory. The canonical density matrix perturbation theory can be used to calculate temperature-dependent response properties from the coupled perturbed self-consistent field equations as in density-functional perturbation theory. The method is well suited to take advantage of sparse matrix algebra to achieve linear scaling complexity in the computational cost as a function of system size for sufficiently large nonmetallic materials and metals at high temperatures. PMID:26764847

  9. Measure of Node Similarity in Multilayer Networks.

    Science.gov (United States)

    Mollgaard, Anders; Zettler, Ingo; Dammeyer, Jesper; Jensen, Mogens H; Lehmann, Sune; Mathiesen, Joachim

    2016-01-01

    The weight of links in a network is often related to the similarity of the nodes. Here, we introduce a simple tunable measure for analysing the similarity of nodes across different link weights. In particular, we use the measure to analyze homophily in a group of 659 freshman students at a large university. Our analysis is based on data obtained using smartphones equipped with custom data collection software, complemented by questionnaire-based data. The network of social contacts is represented as a weighted multilayer network constructed from different channels of telecommunication as well as data on face-to-face contacts. We find that even strongly connected individuals are not more similar with respect to basic personality traits than randomly chosen pairs of individuals. In contrast, several socio-demographics variables have a significant degree of similarity. We further observe that similarity might be present in one layer of the multilayer network and simultaneously be absent in the other layers. For a variable such as gender, our measure reveals a transition from similarity between nodes connected with links of relatively low weight to dis-similarity for the nodes connected by the strongest links. We finally analyze the overlap between layers in the network for different levels of acquaintanceships. PMID:27300084

  10. The baryonic self similarity of dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Alard, C., E-mail: alard@iap.fr [Institut d' Astrophysique de Paris, 98bis boulevard Arago, F-75014 Paris (France)

    2014-06-20

    The cosmological simulations indicates that dark matter halos have specific self-similar properties. However, the halo similarity is affected by the baryonic feedback. By using momentum-driven winds as a model to represent the baryon feedback, an equilibrium condition is derived which directly implies the emergence of a new type of similarity. The new self-similar solution has constant acceleration at a reference radius for both dark matter and baryons. This model receives strong support from the observations of galaxies. The new self-similar properties imply that the total acceleration at larger distances is scale-free, the transition between the dark matter and baryons dominated regime occurs at a constant acceleration, and the maximum amplitude of the velocity curve at larger distances is proportional to M {sup 1/4}. These results demonstrate that this self-similar model is consistent with the basics of modified Newtonian dynamics (MOND) phenomenology. In agreement with the observations, the coincidence between the self-similar model and MOND breaks at the scale of clusters of galaxies. Some numerical experiments show that the behavior of the density near the origin is closely approximated by a Einasto profile.

  11. Efficient Privacy Preserving Protocols for Similarity Join

    Directory of Open Access Journals (Sweden)

    Bilal Hawashin

    2012-04-01

    Full Text Available During the similarity join process, one or more sources may not allow sharing its data with other sources. In this case, a privacy preserving similarity join is required. We showed in our previous work [4] that using long attributes, such as paper abstracts, movie summaries, product descriptions, and user feedbacks, could improve the similarity join accuracy using supervised learning. However, the existing secure protocols for similarity join methods can not be used to join sources using these long attributes. Moreover, the majority of the existing privacy‐preserving protocols do not consider the semantic similarities during the similarity join process. In this paper, we introduce a secure efficient protocol to semantically join sources when the join attributes are long attributes. We provide two secure protocols for both scenarios when a training set exists and when there is no available training set. Furthermore, we introduced the multi‐label supervised secure protocol and the expandable supervised secure protocol. Results show that our protocols can efficiently join sources using the long attributes by considering the semantic relationships among the long string values. Therefore, it improves the overall secure similarity join performance.

  12. Notions of similarity for computational biology models

    KAUST Repository

    Waltemath, Dagmar

    2016-03-21

    Computational models used in biology are rapidly increasing in complexity, size, and numbers. To build such large models, researchers need to rely on software tools for model retrieval, model combination, and version control. These tools need to be able to quantify the differences and similarities between computational models. However, depending on the specific application, the notion of similarity may greatly vary. A general notion of model similarity, applicable to various types of models, is still missing. Here, we introduce a general notion of quantitative model similarities, survey the use of existing model comparison methods in model building and management, and discuss potential applications of model comparison. To frame model comparison as a general problem, we describe a theoretical approach to defining and computing similarities based on different model aspects. Potentially relevant aspects of a model comprise its references to biological entities, network structure, mathematical equations and parameters, and dynamic behaviour. Future similarity measures could combine these model aspects in flexible, problem-specific ways in order to mimic users\\' intuition about model similarity, and to support complex model searches in databases.

  13. Measure of Node Similarity in Multilayer Networks

    Science.gov (United States)

    Mollgaard, Anders; Zettler, Ingo; Dammeyer, Jesper; Jensen, Mogens H.; Lehmann, Sune; Mathiesen, Joachim

    2016-01-01

    The weight of links in a network is often related to the similarity of the nodes. Here, we introduce a simple tunable measure for analysing the similarity of nodes across different link weights. In particular, we use the measure to analyze homophily in a group of 659 freshman students at a large university. Our analysis is based on data obtained using smartphones equipped with custom data collection software, complemented by questionnaire-based data. The network of social contacts is represented as a weighted multilayer network constructed from different channels of telecommunication as well as data on face-to-face contacts. We find that even strongly connected individuals are not more similar with respect to basic personality traits than randomly chosen pairs of individuals. In contrast, several socio-demographics variables have a significant degree of similarity. We further observe that similarity might be present in one layer of the multilayer network and simultaneously be absent in the other layers. For a variable such as gender, our measure reveals a transition from similarity between nodes connected with links of relatively low weight to dis-similarity for the nodes connected by the strongest links. We finally analyze the overlap between layers in the network for different levels of acquaintanceships. PMID:27300084

  14. Boost matrix converters in clean energy systems

    Science.gov (United States)

    Karaman, Ekrem

    This dissertation describes an investigation of novel power electronic converters, based on the ultra-sparse matrix topology and characterized by the minimum number of semiconductor switches. The Z-source, Quasi Z-source, Series Z-source and Switched-inductor Z-source networks were originally proposed for boosting the output voltage of power electronic inverters. These ideas were extended here on three-phase to three-phase and three-phase to single-phase indirect matrix converters. For the three-phase to three-phase matrix converters, the Z-source networks are placed between the three-switch input rectifier stage and the output six-switch inverter stage. A brief shoot-through state produces the voltage boost. An optimal pulse width modulation technique was developed to achieve high boosting capability and minimum switching losses in the converter. For the three-phase to single-phase matrix converters, those networks are placed similarly. For control purposes, a new modulation technique has been developed. As an example application, the proposed converters constitute a viable alternative to the existing solutions in residential wind-energy systems, where a low-voltage variable-speed generator feeds power to the higher-voltage fixed-frequency grid. Comprehensive analytical derivations and simulation results were carried out to investigate the operation of the proposed converters. Performance of the proposed converters was then compared between each other as well as with conventional converters. The operation of the converters was experimentally validated using a laboratory prototype.

  15. Similarity-based pattern analysis and recognition

    CERN Document Server

    Pelillo, Marcello

    2013-01-01

    This accessible text/reference presents a coherent overview of the emerging field of non-Euclidean similarity learning. The book presents a broad range of perspectives on similarity-based pattern analysis and recognition methods, from purely theoretical challenges to practical, real-world applications. The coverage includes both supervised and unsupervised learning paradigms, as well as generative and discriminative models. Topics and features: explores the origination and causes of non-Euclidean (dis)similarity measures, and how they influence the performance of traditional classification alg

  16. Random matrix approach to multivariate categorical data analysis

    CERN Document Server

    Patil, Aashay

    2015-01-01

    Correlation and similarity measures are widely used in all the areas of sciences and social sciences. Often the variables are not numbers but are instead qualitative descriptors called categorical data. We define and study similarity matrix, as a measure of similarity, for the case of categorical data. This is of interest due to a deluge of categorical data, such as movie ratings, top-10 rankings and data from social media, in the public domain that require analysis. We show that the statistical properties of the spectra of similarity matrices, constructed from categorical data, follow those from random matrix theory. We demonstrate this approach by applying it to the data of Indian general elections and sea level pressures in North Atlantic ocean.

  17. Scientific articles recommendation with topic regression and relational matrix factorization

    Institute of Scientific and Technical Information of China (English)

    Ming YANG; Ying-ming LI; Zhongfei(Mark)ZHANG

    2014-01-01

    In this paper we study the problem of recommending scientifi c articles to users in an online community with a new perspective of considering topic regression modeling and articles relational structure analysis simultane-ously. First, we present a novel topic regression model, the topic regression matrix factorization (tr-MF), to solve the problem. The main idea of tr-MF lies in extending the matrix factorization with a probabilistic topic modeling. In particular, tr-MF introduces a regression model to regularize user factors through probabilistic topic modeling under the basic hypothesis that users share similar preferences if they rate similar sets of items. Consequently, tr-MF provides interpretable latent factors for users and items, and makes accurate predictions for community users. To incorporate the relational structure into the framework of tr-MF, we introduce relational matrix factorization. Through combining tr-MF with the relational matrix factorization, we propose the topic regression collective matrix factorization (tr-CMF) model. In addition, we also present the collaborative topic regression model with relational matrix factorization (CTR-RMF) model, which combines the existing collaborative topic regression (CTR) model and relational matrix factorization (RMF). From this point of view, CTR-RMF can be considered as an appropriate baseline for tr-CMF. Further, we demonstrate the efficacy of the proposed models on a large subset of the data from CiteULike, a bibliography sharing service dataset. The proposed models outperform the state-of-the-art matrix factorization models with a signifi cant margin. Specifi cally, the proposed models are effective in making predictions for users with only few ratings or even no ratings, and support tasks that are specifi c to a certain fi eld, neither of which has been addressed in the existing literature.

  18. 维甲酸对大鼠高氧肺损伤的保护机制及其与调控丝裂原活化蛋白激酶的关系%Retinoic acid diminished the expression of lung tissue matrix metalioproteinase-2 and matrix metalioproteinase-9 in hyperoxia-exposed premature rats through regulating mitogen-activated protein kinases

    Institute of Scientific and Technical Information of China (English)

    李文斌; 常立文; 容志惠; 刘汉楚; 张谦慎; 陈红兵; 祝华平; 卢红艳; 王华

    2008-01-01

    目的 探讨维甲酸(RA)对高氧肺损伤保护作用机制及其与调控丝裂原活化蛋白激酶(MAPKs)关系.方法 建立高氧(85%)暴露早产SD大鼠肺损伤模型,运用RT-PCR方法检测基质金属蛋白酶2,9(MMP-2、-9)mRNA表达,采用明胶酶谱法检测MMP-2和MMP-9酶原及活酶表达,采用Western blot技术检测磷酸化和非磷酸化总的ERK1/2、JNK1/2和038蛋白质表达.结果 与空气组比较,高氧暴露4、7、14 d,MMP-2和MMP-9 mRNA的表达均显著提高(P均<0.01),MMP-2活酶(除4 d外)、MMP-9酶原及活酶的表达明显上调(P<0.05或P<0.01),磷酸化ERK1/2、JNK1/2和p38表达显著增加(P均<0.01);与高氧组比较,4、7、14 d时,RA明显下调高氧暴露后MMP-2(除14d外)、MMP.9 mRNA的表达(P<0.01或P<0.05),不同程度降低MMP-2活酶、MMP.9酶原及活酶的表达和显著下调磷酸化JNK1/2、038水平,进一步上调磷酸化ERK1/2表达.结论 高氧暴露显著提高MMP-2和MMP-9表达,是造成肺损伤的重要因素;JNK1/2和p38信号途径可能参与了高氧暴露下早产大鼠肺组织MMP-2和MMP-9的表达调控;RA可通过降低JNK1/2和p38磷酸化水平,抑制MMP-2和MMP-9的高表达和活化,从而发挥高氧肺损伤保护作用.%Objective To further investigate the protective effect of retinoic acid (RA) on hyperoxia ieduced lung iniury and the role of RA as a modulator on mitogen-activated protein kinases (MAPKs).Methods Establishment of hypemxia(85%)induced lung injury model of premature SpragueDawley (SD) rats:21 d gestational age SD rat's fetuses (term=22 d)were delivered by hysterectomy.Within 12-24 h after birth,the premature rat pups were randomly divided into 4 groups:Group I,airexposed control group;Group Ⅱ,hyperoxia-exposed group;Group Ⅲ,air plus RA-exposed group,Group Ⅳ,hypemxia plus RA-exposed group.Group Ⅰ and Ⅲ were remained in room air,and group Ⅱ and Ⅳ were placed in 85% oxygen.The pups in Group Ⅲ and Ⅳ were injected with RA (500 μg/kg,every day

  19. Formation of Metal-Related Ions in Matrix-Assisted Laser Desorption Ionization

    Science.gov (United States)

    Lee, Chuping; Lu, I.-Chung; Hsu, Hsu Chen; Lin, Hou-Yu; Liang, Sheng-Ping; Lee, Yuan-Tseh; Ni, Chi-Kung

    2016-09-01

    In a study of the metal-related ion generation mechanism in matrix-assisted laser desorption ionization (MALDI), crystals of matrix used in MALDI were grown from matrix- and salt-containing solutions. The intensities of metal ion and metal adducts of the matrix ion obtained from unwashed crystals were higher than those from crystals washed with deionized water, indicating that metal ions and metal adducts of the matrix ions are mainly generated from the surface of crystals. The contributions of preformed metal ions and metal adducts of the matrix ions inside the matrix crystals were minor. Metal adducts of the matrix and analyte ion intensities generated from a mixture of dried matrix, salt, and analyte powders were similar to or higher than those generated from the powder of dried droplet crystals, indicating that the contributions of the preformed metal adducts of the matrix and analyte ions were insignificant. Correlation between metal-related ion intensity fluctuation and protonated ion intensity fluctuation was observed, indicating that the generation mechanism of the metal-related ions is similar to that of the protonated ions. Because the thermally induced proton transfer model effectively describes the generation of the protonated ions, we suggest that metal-related ions are mainly generated from the salt dissolution in the matrix melted by the laser.

  20. 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.

  1. 3matrix and 3motif: a protein structure visualization system for conserved sequence motifs

    OpenAIRE

    Bennett, Steven P.; Lu, Lin; Brutlag, Douglas L.

    2003-01-01

    Computational methods such as sequence alignment and motif construction are useful in grouping related proteins into families, as well as helping to annotate new proteins of unknown function. These methods identify conserved amino acids in protein sequences, but cannot determine the specific functional or structural roles of conserved amino acids without additional study. In this work, we present 3matrix (http://3matrix.stanford.edu) and 3motif (http://3motif.stanford.edu), a web-based sequen...

  2. Learning content similarity for music recommendation

    CERN Document Server

    McFee, Brian; Lanckriet, Gert

    2011-01-01

    Many tasks in music information retrieval, such as recommendation, and playlist generation for online radio, fall naturally into the query-by-example setting, wherein a user queries the system by providing a song, and the system responds with a list of relevant or similar song recommendations. Such applications ultimately depend on the notion of similarity between items to produce high-quality results. Current state-of-the-art systems employ collaborative filter methods to represent musical items, effectively comparing items in terms of their constituent users. While collaborative filter techniques perform well when historical data is available for each item, their reliance on historical data impedes performance on novel or unpopular items. To combat this problem, practitioners rely on content-based similarity, which naturally extends to novel items, but is typically out-performed by collaborative filter methods. In this article, we propose a method for optimizing contentbased similarity by learning from a sa...

  3. Bilateral Trade Flows and Income Distribution Similarity

    Science.gov (United States)

    2016-01-01

    Current models of bilateral trade neglect the effects of income distribution. This paper addresses the issue by accounting for non-homothetic consumer preferences and hence investigating the role of income distribution in the context of the gravity model of trade. A theoretically justified gravity model is estimated for disaggregated trade data (Dollar volume is used as dependent variable) using a sample of 104 exporters and 108 importers for 1980–2003 to achieve two main goals. We define and calculate new measures of income distribution similarity and empirically confirm that greater similarity of income distribution between countries implies more trade. Using distribution-based measures as a proxy for demand similarities in gravity models, we find consistent and robust support for the hypothesis that countries with more similar income-distributions trade more with each other. The hypothesis is also confirmed at disaggregated level for differentiated product categories. PMID:27137462

  4. Correlation between social proximity and mobility similarity

    CERN Document Server

    Fan, Chao; Huang, Junming; Rong, Zhihai; Zhou, Tao

    2016-01-01

    Human behaviors exhibit ubiquitous correlations in many aspects, such as individual and collective levels, temporal and spatial dimensions, content, social and geographical layers. With rich Internet data of online behaviors becoming available, it attracts academic interests to explore human mobility similarity from the perspective of social network proximity. Existent analysis shows a strong correlation between online social proximity and offline mobility similari- ty, namely, mobile records between friends are significantly more similar than between strangers, and those between friends with common neighbors are even more similar. We argue the importance of the number and diversity of com- mon friends, with a counter intuitive finding that the number of common friends has no positive impact on mobility similarity while the diversity plays a key role, disagreeing with previous studies. Our analysis provides a novel view for better understanding the coupling between human online and offline behaviors, and will...

  5. Bilateral Trade Flows and Income Distribution Similarity.

    Science.gov (United States)

    Martínez-Zarzoso, Inmaculada; Vollmer, Sebastian

    2016-01-01

    Current models of bilateral trade neglect the effects of income distribution. This paper addresses the issue by accounting for non-homothetic consumer preferences and hence investigating the role of income distribution in the context of the gravity model of trade. A theoretically justified gravity model is estimated for disaggregated trade data (Dollar volume is used as dependent variable) using a sample of 104 exporters and 108 importers for 1980-2003 to achieve two main goals. We define and calculate new measures of income distribution similarity and empirically confirm that greater similarity of income distribution between countries implies more trade. Using distribution-based measures as a proxy for demand similarities in gravity models, we find consistent and robust support for the hypothesis that countries with more similar income-distributions trade more with each other. The hypothesis is also confirmed at disaggregated level for differentiated product categories. PMID:27137462

  6. Distances and similarities in intuitionistic fuzzy sets

    CERN Document Server

    Szmidt, Eulalia

    2014-01-01

    This book presents the state-of-the-art in theory and practice regarding similarity and distance measures for intuitionistic fuzzy sets. Quantifying similarity and distances is crucial for many applications, e.g. data mining, machine learning, decision making, and control. The work provides readers with a comprehensive set of theoretical concepts and practical tools for both defining and determining similarity between intuitionistic fuzzy sets. It describes an automatic algorithm for deriving intuitionistic fuzzy sets from data, which can aid in the analysis of information in large databases. The book also discusses other important applications, e.g. the use of similarity measures to evaluate the extent of agreement between experts in the context of decision making.

  7. Bilateral Trade Flows and Income Distribution Similarity.

    Science.gov (United States)

    Martínez-Zarzoso, Inmaculada; Vollmer, Sebastian

    2016-01-01

    Current models of bilateral trade neglect the effects of income distribution. This paper addresses the issue by accounting for non-homothetic consumer preferences and hence investigating the role of income distribution in the context of the gravity model of trade. A theoretically justified gravity model is estimated for disaggregated trade data (Dollar volume is used as dependent variable) using a sample of 104 exporters and 108 importers for 1980-2003 to achieve two main goals. We define and calculate new measures of income distribution similarity and empirically confirm that greater similarity of income distribution between countries implies more trade. Using distribution-based measures as a proxy for demand similarities in gravity models, we find consistent and robust support for the hypothesis that countries with more similar income-distributions trade more with each other. The hypothesis is also confirmed at disaggregated level for differentiated product categories.

  8. Interpersonal Congruency, Attitude Similarity, and Interpersonal Attraction

    Science.gov (United States)

    Touhey, John C.

    1975-01-01

    As no experimental study has examined the effects of congruency on attraction, the present investigation orthogonally varied attitude similarity and interpersonal congruency in order to compare the two independent variables as determinants of interpersonal attraction. (Author/RK)

  9. Discovering Music Structure via Similarity Fusion

    DEFF Research Database (Denmark)

    Arenas-García, Jerónimo; Parrado-Hernandez, Emilio; Meng, Anders;

    Automatic methods for music navigation and music recommendation exploit the structure in the music to carry out a meaningful exploration of the “song space”. To get a satisfactory performance from such systems, one should incorporate as much information about songs similarity as possible; however...... semantics”, in such a way that all observed similarities can be satisfactorily explained using the latent semantics. Therefore, one can think of these semantics as the real structure in music, in the sense that they can explain the observed similarities among songs. The suitability of the PLSA model...... for representing music structure is studied in a simplified scenario consisting of 4412 songs and two similarity measures among them. The results suggest that the PLSA model is a useful framework to combine different sources of information, and provides a reasonable space for song representation....

  10. SOURCE CODE RETRIEVAL USING SEQUENCE BASED SIMILARITY

    Directory of Open Access Journals (Sweden)

    Yoshihisa Udagawa

    2013-07-01

    Full Text Available Duplicate code adversely affects the quality of software systems and hence should be detected. We discuss an approach that improves source code retrieval using structural information of source code. A lexical parser is developed to extract control statements and method identifiers from Java programs. We propose a similarity measure that is defined by the ratio of the number of sequential fully matching statements to the number of sequential partially matching statements. The defined similarity measure is an extension of the set-based Sorensen-Dice similarity index. This research primarily contributes to the development of a similarity retrieval algorithm that derives meaningful search conditions from a given sequence, and then performs retrieval using all derived conditions. Experiments show that our retrieval model shows an improvement of up to 90.9% over other retrieval models relative to the number of retrieved methods.

  11. Outsourced similarity search on metric data assets

    KAUST Repository

    Yiu, Man Lung

    2012-02-01

    This paper considers a cloud computing setting in which similarity querying of metric data is outsourced to a service provider. The data is to be revealed only to trusted users, not to the service provider or anyone else. Users query the server for the most similar data objects to a query example. Outsourcing offers the data owner scalability and a low-initial investment. The need for privacy may be due to the data being sensitive (e.g., in medicine), valuable (e.g., in astronomy), or otherwise confidential. Given this setting, the paper presents techniques that transform the data prior to supplying it to the service provider for similarity queries on the transformed data. Our techniques provide interesting trade-offs between query cost and accuracy. They are then further extended to offer an intuitive privacy guarantee. Empirical studies with real data demonstrate that the techniques are capable of offering privacy while enabling efficient and accurate processing of similarity queries.

  12. Integrated Semantic Similarity Model Based on Ontology

    Institute of Scientific and Technical Information of China (English)

    LIU Ya-Jun; ZHAO Yun

    2004-01-01

    To solve the problem of the inadequacy of semantic processing in the intelligent question answering system, an integrated semantic similarity model which calculates the semantic similarity using the geometric distance and information content is presented in this paper.With the help of interrelationship between concepts, the information content of concepts and the strength of the edges in the ontology network, we can calculate the semantic similarity between two concepts and provide information for the further calculation of the semantic similarity between user's question and answers in knowlegdge base.The results of the experiments on the prototype have shown that the semantic problem in natural language processing can also be solved with the help of the knowledge and the abundant semantic information in ontology.More than 90% accuracy with less than 50 ms average searching time in the intelligent question answering prototype system based on ontology has been reached.The result is very satisfied.

  13. Interpersonal attraction and personality: what is attractive--self similarity, ideal similarity, complementarity or attachment security?

    Science.gov (United States)

    Klohnen, Eva C; Luo, Shanhong

    2003-10-01

    Little is known about whether personality characteristics influence initial attraction. Because adult attachment differences influence a broad range of relationship processes, the authors examined their role in 3 experimental attraction studies. The authors tested four major attraction hypotheses--self similarity, ideal-self similarity, complementarity, and attachment security--and examined both actual and perceptual factors. Replicated analyses across samples, designs, and manipulations showed that actual security and self similarity predicted attraction. With regard to perceptual factors, ideal similarity, self similarity, and security all were significant predictors. Whereas perceptual ideal and self similarity had incremental predictive power, perceptual security's effects were subsumed by perceptual ideal similarity. Perceptual self similarity fully mediated actual attachment similarity effects, whereas ideal similarity was only a partial mediator. PMID:14561124

  14. Matrix product operators, matrix product states, and ab initio density matrix renormalization group algorithms.

    Science.gov (United States)

    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. PMID:27394094

  15. Matrix product operators, matrix product states, and ab initio density matrix renormalization group algorithms

    Science.gov (United States)

    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.

  16. Matrix product operators, matrix product states, and ab initio density matrix renormalization group algorithms.

    Science.gov (United States)

    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.

  17. On distributional assumptions and whitened cosine similarities

    DEFF Research Database (Denmark)

    Loog, Marco

    2008-01-01

    Recently, an interpretation of the whitened cosine similarity measure as a Bayes decision rule was proposed (C. Liu, "The Bayes Decision Rule Induced Similarity Measures,'' IEEE Trans. Pattern Analysis and Machine Intelligence, vol. 29, no. 6, pp. 1086-1090, June 2007. This communication makes th...... the observation that some of the distributional assumptions made to derive this measure are very restrictive and, considered simultaneously, even inconsistent....

  18. Some more similarities between Peirce and Skinner

    OpenAIRE

    Moxley, Roy A

    2002-01-01

    C. S. Peirce is noted for pioneering a variety of views, and the case is made here for the similarities and parallels between his views and B. F. Skinner's radical behaviorism. In addition to parallels previously noted, these similarities include an advancement of experimental science, a behavioral psychology, a shift from nominalism to realism, an opposition to positivism, a selectionist account for strengthening behavior, the importance of a community of selves, a recursive approach to meth...

  19. Protein structural similarity search by Ramachandran codes

    Directory of Open Access Journals (Sweden)

    Chang Chih-Hung

    2007-08-01

    Full Text Available Abstract Background Protein structural data has increased exponentially, such that fast and accurate tools are necessary to access structure similarity search. To improve the search speed, several methods have been designed to reduce three-dimensional protein structures to one-dimensional text strings that are then analyzed by traditional sequence alignment methods; however, the accuracy is usually sacrificed and the speed is still unable to match sequence similarity search tools. Here, we aimed to improve the linear encoding methodology and develop efficient search tools that can rapidly retrieve structural homologs from large protein databases. Results We propose a new linear encoding method, SARST (Structural similarity search Aided by Ramachandran Sequential Transformation. SARST transforms protein structures into text strings through a Ramachandran map organized by nearest-neighbor clustering and uses a regenerative approach to produce substitution matrices. Then, classical sequence similarity search methods can be applied to the structural similarity search. Its accuracy is similar to Combinatorial Extension (CE and works over 243,000 times faster, searching 34,000 proteins in 0.34 sec with a 3.2-GHz CPU. SARST provides statistically meaningful expectation values to assess the retrieved information. It has been implemented into a web service and a stand-alone Java program that is able to run on many different platforms. Conclusion As a database search method, SARST can rapidly distinguish high from low similarities and efficiently retrieve homologous structures. It demonstrates that the easily accessible linear encoding methodology has the potential to serve as a foundation for efficient protein structural similarity search tools. These search tools are supposed applicable to automated and high-throughput functional annotations or predictions for the ever increasing number of published protein structures in this post-genomic era.

  20. SIMILARITY NETWORK FOR SEMANTIC WEB SERVICES SUBSTITUTION

    OpenAIRE

    Cherifi, Chantal

    2013-01-01

    Web services substitution is one of the most challenging tasks for automating the composition process of multiple Web services. It aims to improve performances and to deal efficiently with Web services failures. Many existing solutions have approached the problem through classification of substitutable Web services. To go a step further, we propose in this paper a network based approach where nodes are Web services operations and links join similar operations. Four similarity measures based o...

  1. Limit theorems for self-similar tilings

    CERN Document Server

    Bufetov, Alexander I

    2012-01-01

    We study deviation of ergodic averages for dynamical systems given by self-similar tilings on the plane and in higher dimensions. The main object of our paper is a special family of finitely-additive measures for our systems. An asymptotic formula is given for ergodic integrals in terms of these finitely-additive measures, and, as a corollary, limit theorems are obtained for dynamical systems given by self-similar tilings.

  2. Protein structural similarity search by Ramachandran codes

    OpenAIRE

    Chang Chih-Hung; Huang Po-Jung; Lo Wei-Cheng; Lyu Ping-Chiang

    2007-01-01

    Abstract Background Protein structural data has increased exponentially, such that fast and accurate tools are necessary to access structure similarity search. To improve the search speed, several methods have been designed to reduce three-dimensional protein structures to one-dimensional text strings that are then analyzed by traditional sequence alignment methods; however, the accuracy is usually sacrificed and the speed is still unable to match sequence similarity search tools. Here, we ai...

  3. Mobile P2P Fast Similarity Search

    OpenAIRE

    Bocek, T; Hecht, F. V.; Hausheer, D; Hunt, E; Stiller, B.

    2009-01-01

    In informal data sharing environments, misspellings cause problems for data indexing and retrieval. This is even more pronounced in mobile environments, in which devices with limited input devices are used. In a mobile environment, similarity search algorithms for finding misspelled data need to account for limited CPU and bandwidth. This demo shows P2P fast similarity search (P2PFastSS) running on mobile phones and laptops that is tailored to uncertain data entry and use...

  4. Privacy-preserving matching of similar patients.

    Science.gov (United States)

    Vatsalan, Dinusha; Christen, Peter

    2016-02-01

    The identification of similar entities represented by records in different databases has drawn considerable attention in many application areas, including in the health domain. One important type of entity matching application that is vital for quality healthcare analytics is the identification of similar patients, known as similar patient matching. A key component of identifying similar records is the calculation of similarity of the values in attributes (fields) between these records. Due to increasing privacy and confidentiality concerns, using the actual attribute values of patient records to identify similar records across different organizations is becoming non-trivial because the attributes in such records often contain highly sensitive information such as personal and medical details of patients. Therefore, the matching needs to be based on masked (encoded) values while being effective and efficient to allow matching of large databases. Bloom filter encoding has widely been used as an efficient masking technique for privacy-preserving matching of string and categorical values. However, no work on Bloom filter-based masking of numerical data, such as integer (e.g. age), floating point (e.g. body mass index), and modulus (numbers wrap around upon reaching a certain value, e.g. date and time), which are commonly required in the health domain, has been presented in the literature. We propose a framework with novel methods for masking numerical data using Bloom filters, thereby facilitating the calculation of similarities between records. We conduct an empirical study on publicly available real-world datasets which shows that our framework provides efficient masking and achieves similar matching accuracy compared to the matching of actual unencoded patient records. PMID:26707453

  5. GoM Diet Matrix

    Data.gov (United States)

    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...

  6. Matrix Quantum Mechanics from Qubits

    CERN Document Server

    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.

  7. Activity-relevant similarity values for fingerprints and implications for similarity searching

    OpenAIRE

    Swarit Jasial; Ye Hu; Martin Vogt; Jürgen Bajorath

    2016-01-01

    A largely unsolved problem in chemoinformatics is the issue of how calculated compound similarity relates to activity similarity, which is central to many applications. In general, activity relationships are predicted from calculated similarity values. However, there is no solid scientific foundation to bridge between calculated molecular and observed activity similarity. Accordingly, the success rate of identifying new active compounds by similarity searching is limited. Although various att...

  8. Mechanisms for similarity matching in disparity measurement

    Directory of Open Access Journals (Sweden)

    Ross eGoutcher

    2014-01-01

    Full Text Available Early neural mechanisms for the measurement of binocular disparity appear to operate in a manner consistent with cross-correlation-like processes. Consequently, cross-correlation, or cross-correlation-like procedures have been used in a range of models of disparity measurement. Using such procedures as the basis for disparity measurement creates a preference for correspondence solutions that maximise the similarity between local left and right eye image regions. Here, we examine how observers’ perception of depth in an ambiguous stereogram is affected by manipulations of luminance and orientation-based image similarity. Results show a strong effect of coarse-scale luminance similarity manipulations, but a relatively weak effect of finer-scale manipulations of orientation similarity. This is in contrast to the measurements of depth obtained from a standard cross-correlation model. This model shows strong effects of orientation similarity manipulations and weaker effects of luminance similarity. In order to account for these discrepancies, the standard cross-correlation approach may be modified to include an initial spatial frequency filtering stage. The performance of this adjusted model most closely matches human psychophysical data when spatial frequency filtering favours coarser scales. This is consistent with the operation of disparity measurement processes where spatial frequency and disparity tuning are correlated, or where disparity measurement operates in a coarse-to-fine manner.

  9. Film review: The Matrix cult

    OpenAIRE

    Tumanov, Vladimir

    2003-01-01

    Much of the semiotic discussion around the deeper structures of "The Matrix" has tended to center around positive ethical and philosophical systems. Thus, numerous critics have pointed out the Christian subtext in the film with Neo as Christ and Morpheus as John the Baptist (James L. Ford: 8). The Garden of Eden story has been superimposed on "The Matrix" as well with the implication that just as Adam's and Eve's awakening to knowledge makes Christianity possible, so too, Neo's awakening will...

  10. Hyaluronan-Dependent Pericellular Matrix

    OpenAIRE

    Evanko, Stephen P.; Tammi, Markku I; Tammi, Raija H.; Wight, Thomas N.

    2007-01-01

    Hyaluronan is a multifunctional glycosaminoglycan that forms the structural basis of the pericellular matrix. Hyaluronan is extruded directly through the plasma membrane by one of three hyaluronan synthases and anchored to the cell surface by the synthase or cell surface receptors such as CD44 or RHAMM. Aggregating proteoglycans and other hyaluronan-binding proteins, contribute to the material and biological properties of the matrix and regulate cell and tissue function. The pericellular matr...

  11. Flows for rectangular matrix models

    OpenAIRE

    Lafrance, Rene; Myers, Robert C.

    1993-01-01

    Several new results on the multicritical behavior of rectangular matrix models are presented. We calculate the free energy in the saddle point approximation, and show that at the triple-scaling point, the result is the same as that derived from the recursion formulae. In the triple-scaling limit, we obtain the string equation and a flow equation for arbitrary multicritical points. Parametric solutions are also examined for the limit of almost-square matrix models. This limit is shown to provi...

  12. Matrix analysis of electrical machinery

    CERN Document Server

    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

  13. Staggered chiral random matrix theory

    International Nuclear Information System (INIS)

    We present a random matrix theory for the staggered lattice QCD Dirac operator. The staggered random matrix theory is equivalent to the zero-momentum limit of the staggered chiral Lagrangian and includes all taste breaking terms at their leading order. This is an extension of previous work which only included some of the taste breaking terms. We will also present some results for the taste breaking contributions to the partition function and the Dirac eigenvalues.

  14. M-theoretic matrix models

    CERN Document Server

    Grassi, Alba

    2014-01-01

    Some matrix models admit, on top of the usual 't Hooft expansion, an M-theory-like expansion, i.e. an expansion at large N but where the rest of the parameters are fixed, instead of scaling with N. These models, which we call M-theoretic matrix models, appear in the localization of Chern-Simons-matter theories, and also in two-dimensional statistical physics. Generically, their partition function receives non-perturbative corrections which are not captured by the 't Hooft expansion. In this paper, we discuss general aspects of these type of matrix integrals and we analyze in detail two different examples. The first one is the matrix model computing the partition function of N=4 supersymmetric Yang-Mills theory in three dimensions with one adjoint hypermultiplet and N_f fundamentals, which has a conjectured M-theory dual, and which we call the N_f matrix model. The second one, which we call the polymer matrix model, computes form factors of the 2d Ising model and is related to the physics of 2d polymers. In bo...

  15. Identifying mechanistic similarities in drug responses

    KAUST Repository

    Zhao, C.

    2012-05-15

    Motivation: In early drug development, it would be beneficial to be able to identify those dynamic patterns of gene response that indicate that drugs targeting a particular gene will be likely or not to elicit the desired response. One approach would be to quantitate the degree of similarity between the responses that cells show when exposed to drugs, so that consistencies in the regulation of cellular response processes that produce success or failure can be more readily identified.Results: We track drug response using fluorescent proteins as transcription activity reporters. Our basic assumption is that drugs inducing very similar alteration in transcriptional regulation will produce similar temporal trajectories on many of the reporter proteins and hence be identified as having similarities in their mechanisms of action (MOA). The main body of this work is devoted to characterizing similarity in temporal trajectories/signals. To do so, we must first identify the key points that determine mechanistic similarity between two drug responses. Directly comparing points on the two signals is unrealistic, as it cannot handle delays and speed variations on the time axis. Hence, to capture the similarities between reporter responses, we develop an alignment algorithm that is robust to noise, time delays and is able to find all the contiguous parts of signals centered about a core alignment (reflecting a core mechanism in drug response). Applying the proposed algorithm to a range of real drug experiments shows that the result agrees well with the prior drug MOA knowledge. © The Author 2012. Published by Oxford University Press. All rights reserved.

  16. SVD row or column symmetric matrix

    Institute of Scientific and Technical Information of China (English)

    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.

  17. Similarity Metrics for Closed Loop Dynamic Systems

    Science.gov (United States)

    Whorton, Mark S.; Yang, Lee C.; Bedrossian, Naz; Hall, Robert A.

    2008-01-01

    To what extent and in what ways can two closed-loop dynamic systems be said to be "similar?" This question arises in a wide range of dynamic systems modeling and control system design applications. For example, bounds on error models are fundamental to the controller optimization with modern control design methods. Metrics such as the structured singular value are direct measures of the degree to which properties such as stability or performance are maintained in the presence of specified uncertainties or variations in the plant model. Similarly, controls-related areas such as system identification, model reduction, and experimental model validation employ measures of similarity between multiple realizations of a dynamic system. Each area has its tools and approaches, with each tool more or less suited for one application or the other. Similarity in the context of closed-loop model validation via flight test is subtly different from error measures in the typical controls oriented application. Whereas similarity in a robust control context relates to plant variation and the attendant affect on stability and performance, in this context similarity metrics are sought that assess the relevance of a dynamic system test for the purpose of validating the stability and performance of a "similar" dynamic system. Similarity in the context of system identification is much more relevant than are robust control analogies in that errors between one dynamic system (the test article) and another (the nominal "design" model) are sought for the purpose of bounding the validity of a model for control design and analysis. Yet system identification typically involves open-loop plant models which are independent of the control system (with the exception of limited developments in closed-loop system identification which is nonetheless focused on obtaining open-loop plant models from closed-loop data). Moreover the objectives of system identification are not the same as a flight test and

  18. Earthquake detection through computationally efficient similarity search.

    Science.gov (United States)

    Yoon, Clara E; O'Reilly, Ossian; Bergen, Karianne J; Beroza, Gregory C

    2015-12-01

    Seismology is experiencing rapid growth in the quantity of data, which has outpaced the development of processing algorithms. Earthquake detection-identification of seismic events in continuous data-is a fundamental operation for observational seismology. We developed an efficient method to detect earthquakes using waveform similarity that overcomes the disadvantages of existing detection methods. Our method, called Fingerprint And Similarity Thresholding (FAST), can analyze a week of continuous seismic waveform data in less than 2 hours, or 140 times faster than autocorrelation. FAST adapts a data mining algorithm, originally designed to identify similar audio clips within large databases; it first creates compact "fingerprints" of waveforms by extracting key discriminative features, then groups similar fingerprints together within a database to facilitate fast, scalable search for similar fingerprint pairs, and finally generates a list of earthquake detections. FAST detected most (21 of 24) cataloged earthquakes and 68 uncataloged earthquakes in 1 week of continuous data from a station located near the Calaveras Fault in central California, achieving detection performance comparable to that of autocorrelation, with some additional false detections. FAST is expected to realize its full potential when applied to extremely long duration data sets over a distributed network of seismic stations. The widespread application of FAST has the potential to aid in the discovery of unexpected seismic signals, improve seismic monitoring, and promote a greater understanding of a variety of earthquake processes. PMID:26665176

  19. Efficient Video Similarity Measurement and Search

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, S-C S

    2002-12-19

    The amount of information on the world wide web has grown enormously since its creation in 1990. Duplication of content is inevitable because there is no central management on the web. Studies have shown that many similar versions of the same text documents can be found throughout the web. This redundancy problem is more severe for multimedia content such as web video sequences, as they are often stored in multiple locations and different formats to facilitate downloading and streaming. Similar versions of the same video can also be found, unknown to content creators, when web users modify and republish original content using video editing tools. Identifying similar content can benefit many web applications and content owners. For example, it will reduce the number of similar answers to a web search and identify inappropriate use of copyright content. In this dissertation, they present a system architecture and corresponding algorithms to efficiently measure, search, and organize similar video sequences found on any large database such as the web.

  20. Earthquake detection through computationally efficient similarity search

    Science.gov (United States)

    Yoon, Clara E.; O’Reilly, Ossian; Bergen, Karianne J.; Beroza, Gregory C.

    2015-01-01

    Seismology is experiencing rapid growth in the quantity of data, which has outpaced the development of processing algorithms. Earthquake detection—identification of seismic events in continuous data—is a fundamental operation for observational seismology. We developed an efficient method to detect earthquakes using waveform similarity that overcomes the disadvantages of existing detection methods. Our method, called Fingerprint And Similarity Thresholding (FAST), can analyze a week of continuous seismic waveform data in less than 2 hours, or 140 times faster than autocorrelation. FAST adapts a data mining algorithm, originally designed to identify similar audio clips within large databases; it first creates compact “fingerprints” of waveforms by extracting key discriminative features, then groups similar fingerprints together within a database to facilitate fast, scalable search for similar fingerprint pairs, and finally generates a list of earthquake detections. FAST detected most (21 of 24) cataloged earthquakes and 68 uncataloged earthquakes in 1 week of continuous data from a station located near the Calaveras Fault in central California, achieving detection performance comparable to that of autocorrelation, with some additional false detections. FAST is expected to realize its full potential when applied to extremely long duration data sets over a distributed network of seismic stations. The widespread application of FAST has the potential to aid in the discovery of unexpected seismic signals, improve seismic monitoring, and promote a greater understanding of a variety of earthquake processes. PMID:26665176