WorldWideScience

Sample records for gene-gene interaction study

  1. Reconstructability analysis as a tool for identifying gene-gene interactions in studies of human diseases.

    Science.gov (United States)

    Shervais, Stephen; Kramer, Patricia L; Westaway, Shawn K; Cox, Nancy J; Zwick, Martin

    2010-01-01

    There are a number of common human diseases for which the genetic component may include an epistatic interaction of multiple genes. Detecting these interactions with standard statistical tools is difficult because there may be an interaction effect, but minimal or no main effect. Reconstructability analysis (RA) uses Shannon's information theory to detect relationships between variables in categorical datasets. We applied RA to simulated data for five different models of gene-gene interaction, and find that even with heritability levels as low as 0.008, and with the inclusion of 50 non-associated genes in the dataset, we can identify the interacting gene pairs with an accuracy of > or =80%. We applied RA to a real dataset of type 2 non-insulin-dependent diabetes (NIDDM) cases and controls, and closely approximated the results of more conventional single SNP disease association studies. In addition, we replicated prior evidence for epistatic interactions between SNPs on chromosomes 2 and 15.

  2. Association and gene-gene interactions study of reelin signaling pathway related genes with autism in the Han Chinese population.

    Science.gov (United States)

    Shen, Yidong; Xun, Guanglei; Guo, Hui; He, Yiqun; Ou, Jianjun; Dong, Huixi; Xia, Kun; Zhao, Jingping

    2016-04-01

    Autism is a neurodevelopmental disorder with unclear etiology. Reelin had been proposed to participate in the etiology of autism due to its important role in brain development. The goal of this study was to explore the association and gene-gene interactions of reelin signaling pathway related genes (RELN, VLDLR, LRP8, DAB1, FYN, and CDK5) with autism in Han Chinese population. Genotyping data of the six genes were obtained from a recent genome-wide association study performed in 430 autistic children who fulfilled the DSM-IV-TR criteria for autistic disorder, and 1,074 healthy controls. Single marker case-control association analysis and haplotype case-control association analysis were conducted after the data was screened. Multifactor dimensionality reduction (MDR) was applied to further test gene-gene interactions. Neither the single marker nor the haplotype association tests found any significant difference between the autistic group and the control group after permutation test of 1,000 rounds. The 4-locus MDR model (comprising rs6143734, rs1858782, rs634500, and rs1924267 which belong to RELN and DAB1) was determined to be the model with the highest cross-validation consistency (CVC) and testing balanced accuracy. The results indicate that an interaction between RELN and DAB1 may increase the risk of autism in the Han Chinese population. Furthermore, it can also be inferred that the involvement of RELN in the etiology of autism would occur through interaction with DAB1.

  3. GEGEINTOOL: A Computer-Based Tool for Automated Analysis of Gene-Gene Interactions in Large Epidemiological Studies in Cardiovascular Genomics

    Directory of Open Access Journals (Sweden)

    Oscar Coltell

    2013-06-01

    Full Text Available Current methods of data analysis of gene-gene interactions in complex diseases, after taking into account environmental factors using traditional approaches, are inefficient. High-throughput methods of analysis in large scale studies including thousands of subjects and hundreds of SNPs should be implemented. We developed an integrative computer tool, GEGEINTOOL (GEne- GEne INTeraction tOOL, for large-scale analysis of gene-gene interactions, in human studies of complex diseases including a large number of subjects, SNPs, as well as environmental factors. That resource uses standard statistical packages (SPSS, etc. to build and fit the gene-gene interaction models by means of syntax scripts in predicting one or more continuous or dichotomic phenotypes. Codominant, dominant and recessive genetic interaction models including control for covariates are automatically created for each SNP in order to test the best model. From the standard outputs, GEGEINTOOL extracts a selected set of parameters (regression coefficients, p-values, adjusted means, etc., and groups them in a single MS Excel Spreadsheet. The tool allows editing the set of filter parameters, filtering the selected results depending on p-values, as well as plotting the selected gene-gene interactions to check consistency. In conclusion, GEGEINTOOL is a useful and friendly tool for exploring and identifying gene-gene interactions in complex diseases.

  4. A gene-based information gain method for detecting gene-gene interactions in case-control studies.

    Science.gov (United States)

    Li, Jin; Huang, Dongli; Guo, Maozu; Liu, Xiaoyan; Wang, Chunyu; Teng, Zhixia; Zhang, Ruijie; Jiang, Yongshuai; Lv, Hongchao; Wang, Limei

    2015-11-01

    Currently, most methods for detecting gene-gene interactions (GGIs) in genome-wide association studies are divided into SNP-based methods and gene-based methods. Generally, the gene-based methods can be more powerful than SNP-based methods. Some gene-based entropy methods can only capture the linear relationship between genes. We therefore proposed a nonparametric gene-based information gain method (GBIGM) that can capture both linear relationship and nonlinear correlation between genes. Through simulation with different odds ratio, sample size and prevalence rate, GBIGM was shown to be valid and more powerful than classic KCCU method and SNP-based entropy method. In the analysis of data from 17 genes on rheumatoid arthritis, GBIGM was more effective than the other two methods as it obtains fewer significant results, which was important for biological verification. Therefore, GBIGM is a suitable and powerful tool for detecting GGIs in case-control studies.

  5. Power of multifactor dimensionality reduction and penalized logistic regression for detecting gene-gene Interaction in a case-control study

    Directory of Open Access Journals (Sweden)

    Brott Marcia J

    2009-12-01

    Full Text Available Abstract Background There is a growing awareness that interaction between multiple genes play an important role in the risk of common, complex multi-factorial diseases. Many common diseases are affected by certain genotype combinations (associated with some genes and their interactions. The identification and characterization of these susceptibility genes and gene-gene interaction have been limited by small sample size and large number of potential interactions between genes. Several methods have been proposed to detect gene-gene interaction in a case control study. The penalized logistic regression (PLR, a variant of logistic regression with L2 regularization, is a parametric approach to detect gene-gene interaction. On the other hand, the Multifactor Dimensionality Reduction (MDR is a nonparametric and genetic model-free approach to detect genotype combinations associated with disease risk. Methods We compared the power of MDR and PLR for detecting two-way and three-way interactions in a case-control study through extensive simulations. We generated several interaction models with different magnitudes of interaction effect. For each model, we simulated 100 datasets, each with 200 cases and 200 controls and 20 SNPs. We considered a wide variety of models such as models with just main effects, models with only interaction effects or models with both main and interaction effects. We also compared the performance of MDR and PLR to detect gene-gene interaction associated with acute rejection(AR in kidney transplant patients. Results In this paper, we have studied the power of MDR and PLR for detecting gene-gene interaction in a case-control study through extensive simulation. We have compared their performances for different two-way and three-way interaction models. We have studied the effect of different allele frequencies on these methods. We have also implemented their performance on a real dataset. As expected, none of these methods were

  6. Gene-gene Interaction Analyses for Atrial Fibrillation

    NARCIS (Netherlands)

    Lin, Honghuang; Mueller-Nurasyid, Martina; Smith, Albert V; Arking, Dan E; Barnard, John; Bartz, Traci M; Lunetta, Kathryn L; Lohman, Kurt; Kleber, Marcus E; Lubitz, Steven A; Geelhoed, Bastiaan; Trompet, Stella; Niemeijer, Maartje N; Kacprowski, Tim; Chasman, Daniel I; Klarin, Derek; Sinner, Moritz F; Waldenberger, Melanie; Meitinger, Thomas; Harris, Tamara B; Launer, Lenore J; Soliman, Elsayed Z; Chen, Lin Y; Smith, Jonathan D; Van Wagoner, David R; Rotter, Jerome I; Psaty, Bruce M; Xie, Zhijun; Hendricks, Audrey E; Ding, Jingzhong; Delgado, Graciela E; Verweij, Niek; van der Harst, Pim; Macfarlane, Peter W; Ford, Ian; Hofman, Albert; Uitterlinden, André; Heeringa, Jan; Franco, Oscar H; Kors, Jan A; Weiss, Stefan; Völzke, Henry; Rose, Lynda M; Natarajan, Pradeep; Kathiresan, Sekar; Kääb, Stefan; Gudnason, Vilmundur; Alonso, Alvaro; Chung, Mina K; Heckbert, Susan R; Benjamin, Emelia J; Liu, Yongmei; März, Winfried; Rienstra, Michiel; Jukema, J Wouter; Stricker, Bruno H; Dörr, Marcus; Albert, Christine M; Ellinor, Patrick T

    2016-01-01

    Atrial fibrillation (AF) is a heritable disease that affects more than thirty million individuals worldwide. Extensive efforts have been devoted to the study of genetic determinants of AF. The objective of our study is to examine the effect of gene-gene interaction on AF susceptibility. We performed

  7. Gene-gene Interaction Analyses for Atrial Fibrillation

    NARCIS (Netherlands)

    H. Lin (Honghuang); M. Mueller-Nurasyid; A.V. Smith (Albert Vernon); D.E. Arking (Dan); J. Barnard (John); T.M. Bartz (Traci M.); K.L. Lunetta (Kathryn); K. Lohman (Kurt); M.E. Kleber (Marcus); S.A. Lubitz (Steven); Geelhoed, B. (Bastiaan); S. Trompet (Stella); M.N. Niemeijer (Maartje); T. Kacprowski (Tim); D.I. Chasman (Daniel); Klarin, D. (Derek); M.F. Sinner (Moritz); M. Waldenberger (Melanie); T. Meitinger (Thomas); T.B. Harris (Tamara); Launer, L.J. (Lenore J.); E.Z. Soliman (Elsayed Z.); L. Chen (Lin); J.D. Smith (Jonathan); D.R. van Wagoner (David); Rotter, J.I. (Jerome I.); B.M. Psaty (Bruce); Xie, Z. (Zhijun); A.E. Hendricks (Audrey E.); Ding, J. (Jingzhong); G.E. Delgado (Graciela E.); N. Verweij (Niek); P. van der Harst (Pim); P.W. MacFarlane (Peter); I. Ford (Ian); A. Hofman (Albert); A.G. Uitterlinden (André); J. Heeringa (Jan); O.H. Franco (Oscar); J.A. Kors (Jan); Weiss, S. (Stefan); H. Völzke (Henry); L.M. Rose (Lynda); Natarajan, P. (Pradeep); S. Kathiresan (Sekar); S. Kääb (Stefan); V. Gudnason (Vilmundur); A. Alonso (Alvaro); M.K. Chung (Mina); S.R. Heckbert (Susan); E.J. Benjamin (Emelia); Y. Liu (Yongmei); W. März (Winfried); S.A. Rienstra; J.W. Jukema (Jan Wouter); B.H.Ch. Stricker (Bruno); M. Dörr (Marcus); C.M. Albert (Christine); P.T. Ellinor (Patrick)

    2016-01-01

    textabstractAtrial fibrillation (AF) is a heritable disease that affects more than thirty million individuals worldwide. Extensive efforts have been devoted to the study of genetic determinants of AF. The objective of our study is to examine the effect of gene-gene interaction on AF susceptibility.

  8. GENIE: a software package for gene-gene interaction analysis in genetic association studies using multiple GPU or CPU cores.

    Science.gov (United States)

    Chikkagoudar, Satish; Wang, Kai; Li, Mingyao

    2011-05-26

    Gene-gene interaction in genetic association studies is computationally intensive when a large number of SNPs are involved. Most of the latest Central Processing Units (CPUs) have multiple cores, whereas Graphics Processing Units (GPUs) also have hundreds of cores and have been recently used to implement faster scientific software. However, currently there are no genetic analysis software packages that allow users to fully utilize the computing power of these multi-core devices for genetic interaction analysis for binary traits. Here we present a novel software package GENIE, which utilizes the power of multiple GPU or CPU processor cores to parallelize the interaction analysis. GENIE reads an entire genetic association study dataset into memory and partitions the dataset into fragments with non-overlapping sets of SNPs. For each fragment, GENIE analyzes: 1) the interaction of SNPs within it in parallel, and 2) the interaction between the SNPs of the current fragment and other fragments in parallel. We tested GENIE on a large-scale candidate gene study on high-density lipoprotein cholesterol. Using an NVIDIA Tesla C1060 graphics card, the GPU mode of GENIE achieves a speedup of 27 times over its single-core CPU mode run. GENIE is open-source, economical, user-friendly, and scalable. Since the computing power and memory capacity of graphics cards are increasing rapidly while their cost is going down, we anticipate that GENIE will achieve greater speedups with faster GPU cards. Documentation, source code, and precompiled binaries can be downloaded from http://www.cceb.upenn.edu/~mli/software/GENIE/.

  9. Testing for gene-gene interaction with AMMI models.

    Science.gov (United States)

    Barhdadi, Amina; Dubé, Marie-Pierre

    2010-01-01

    Studies have shown that many common diseases are influenced by multiple genes and their interactions. There is currently a strong interest in testing for association between combinations of these genes and disease, in particular because genes that affect the risk of disease only in the presence of another genetic variant may not be detected in marginal analysis. In this paper we propose the use of additive main effect and multiplicative interaction (AMMI) models to detect and to quantify gene-gene interaction effects for a quantitative trait. The objective of the present research is to demonstrate the practical advantages of these models to describe complex interaction between two unlinked loci. Although gene-gene interactions have often been defined as a deviance from additive genetic effects, the residual term has generally not been appropriately treated. The AMMI models allow for the analysis of a two way factorial data structure and combine the analysis of variance of the two main genotype effects with a principal component analysis of the residual multiplicative interaction. The AMMI models for gene-gene interaction presented here allow for the testing of non additivity between the two loci, and also describe how their interaction structure fits the existing non-additivity. Moreover, these models can be used to identify the specific two genotypes combinations that contribute to the significant gene-gene interaction. We describe the use of the biplot to display the structure of the interaction and evaluate the performance of the AMMI and the special cases of the AMMI previously described by Tukey and Mandel with simulated data sets. Our simulated study showed that the AMMI model is as powerful as general linear models when the interaction is not modeled in the presence of marginal effects. However, in the presence of pure epitasis, i.e. in the absence of marginal effects, the AMMI method was not found to be superior to other tested regression methods.

  10. Association study of polymorphisms in the ABO gene and their gene-gene interactions with ischemic stroke in Chinese population.

    Science.gov (United States)

    Li, Hao; Cai, Yong; Xu, An-Ding

    2017-10-06

    To investigate the impact of 4 single nucleotide polymorphisms (SNPs) within ABO gene and their gene-gene interactions on ischemic stroke (IS) susceptibility in Chinese Han population. A total of 1993 participants (1375 males, 618 females) were selected, including 991 IS patients and 1002 normal controls. The SNPstats (http://bioinfo.iconcologia.net/SNPstats) was used for Hardy-Weinberg equilibrium (HWE) test. Generalized multifactor dimensionality reduction (GMDR) was used to screen the best interaction combination among 4 SNPs within ABO gene. Logistic regression was performed to calculate the ORs (95%CI) for interaction between SNPs. Both rs579459 and rs505922 within ABO gene were associated with IS risk in additive and dominant models. IS risks were higher in those with minor alleles of rs579459 and rs505922 than those with wild-type homozygotes, OR (95%CI) were 1.62 (1.19-2.10) and 1.69 (1.23-2.18), respectively. We did not find any relation of rs651007 and rs529565 with IS risk in both additive and dominant models. GMDR model indicated a significant two-locus model (P = .0010) involving rs505922 and rs579459, indicating a potential interaction between rs505922 and rs579459, the cross-validation consistency of the two-locus models was 9/10, and the testing accuracy was 60.72%. We also found that participants with rs505922- TC/CC and rs579459- TC/CC genotype have the highest IS risk, compared to participants with rs505922- TT and rs579459- TT genotype, OR (95%CI) was 2.94 (1.28-4.66). We found that rs579459 and rs505922 within ABO gene and their interaction were both associated with increased IS risk in Chinese population. © 2017 Wiley Periodicals, Inc.

  11. A global test for gene-gene interactions based on random matrix theory.

    Science.gov (United States)

    Frost, H Robert; Amos, Christopher I; Moore, Jason H

    2016-12-01

    Statistical interactions between markers of genetic variation, or gene-gene interactions, are believed to play an important role in the etiology of many multifactorial diseases and other complex phenotypes. Unfortunately, detecting gene-gene interactions is extremely challenging due to the large number of potential interactions and ambiguity regarding marker coding and interaction scale. For many data sets, there is insufficient statistical power to evaluate all candidate gene-gene interactions. In these cases, a global test for gene-gene interactions may be the best option. Global tests have much greater power relative to multiple individual interaction tests and can be used on subsets of the markers as an initial filter prior to testing for specific interactions. In this paper, we describe a novel global test for gene-gene interactions, the global epistasis test (GET), that is based on results from random matrix theory. As we show via simulation studies based on previously proposed models for common diseases including rheumatoid arthritis, type 2 diabetes, and breast cancer, our proposed GET method has superior performance characteristics relative to existing global gene-gene interaction tests. A glaucoma GWAS data set is used to demonstrate the practical utility of the GET method.

  12. Gene-gene interaction between tuberculosis candidate genes in a South African population.

    Science.gov (United States)

    de Wit, Erika; van der Merwe, Lize; van Helden, Paul D; Hoal, Eileen G

    2011-02-01

    In a complex disease such as tuberculosis (TB) it is increasingly evident that gene-gene interactions play a far more important role in an individual's susceptibility to develop the disease than single polymorphisms on their own, as one gene can enhance or hinder the expression of another gene. Gene-gene interaction analysis is a new approach to elucidate susceptibility to TB. The possibility of gene-gene interactions was assessed, focusing on 11 polymorphisms in nine genes (DC-SIGN, IFN-γ, IFNGR1, IL-8, IL-1Ra, MBL, NRAMP1, RANTES, and SP-D) that have been associated with TB, some repeatedly. An optimal model, which best describes and predicts TB case-control status, was constructed. Significant interactions were detected between eight pairs of variants. The models fitted the observed data extremely well, with p activation is greatly enhanced by IFN-γ and IFN-γ response elements that are present in the human NRAMP1 promoter region, providing further evidence for their interaction. This study enabled us to test the theory that disease outcome may be due to interaction of several gene effects. With eight instances of statistically significant gene-gene interactions, the importance of epistasis is clearly identifiable in this study. Methods for studying gene-gene interactions are based on a multilocus and multigene approach, consistent with the nature of complex-trait diseases, and may provide the paradigm for future genetic studies of TB.

  13. BiForce Toolbox: powerful high-throughput computational analysis of gene-gene interactions in genome-wide association studies.

    Science.gov (United States)

    Gyenesei, Attila; Moody, Jonathan; Laiho, Asta; Semple, Colin A M; Haley, Chris S; Wei, Wen-Hua

    2012-07-01

    Genome-wide association studies (GWAS) have discovered many loci associated with common disease and quantitative traits. However, most GWAS have not studied the gene-gene interactions (epistasis) that could be important in complex trait genetics. A major challenge in analysing epistasis in GWAS is the enormous computational demands of analysing billions of SNP combinations. Several methods have been developed recently to address this, some using computers equipped with particular graphical processing units, most restricted to binary disease traits and all poorly suited to general usage on the most widely used operating systems. We have developed the BiForce Toolbox to address the demand for high-throughput analysis of pairwise epistasis in GWAS of quantitative and disease traits across all commonly used computer systems. BiForce Toolbox is a stand-alone Java program that integrates bitwise computing with multithreaded parallelization and thus allows rapid full pairwise genome scans via a graphical user interface or the command line. Furthermore, BiForce Toolbox incorporates additional tests of interactions involving SNPs with significant marginal effects, potentially increasing the power of detection of epistasis. BiForce Toolbox is easy to use and has been applied in multiple studies of epistasis in large GWAS data sets, identifying interesting interaction signals and pathways.

  14. Association of Combined Maternal-Fetal TNF-α Gene G308A Genotypes with Preterm Delivery: A Gene-Gene Interaction Study

    Directory of Open Access Journals (Sweden)

    Mingbin Liang

    2010-01-01

    Full Text Available Preterm delivery (PTD is a complicated perinatal adverse event. We were interested in association of G308A polymorphism in tumor necrosis factor-α (TNF-α gene with PTD; so we conducted a genetic epidemiology study in Anqing City, Anhui Province, China. Case families and control families were all collected between July 1999 and June 2002. To control potential population stratification as we could, all eligible subjects were ethnic Han Chinese. 250 case families and 247 control families were included in data analysis. A hybrid design which combines case-parent triads and control parents was employed, to test maternal-fetal genotype (MFG incompatibility. The method is based on a log-linear modeling approach. In summary, we found that when the mother's or child's genotype was G/A, there was a reduced risk of PTD; however when the mother's or child's genotype was genotype A/A, there was a relatively higher risk of PTD. Combined maternal-fetal genotype GA/GA showed the most reduced risk of PTD. Comparison of the LRTs showed that the model with maternal-fetal genotype effects fits significantly better than the model with only maternal and fetal genotype main effects (log-likelihood = −719.4, P=.023, significant at 0.05 level. That means that the combined maternal-fetal genotype incompatibility was significantly associated with PTD. The model with maternal-fetal genotype effects can be considered a gene-gene interaction model. We claim that both maternal effects and fetal effects should be considered together while investigating genetic factors of certain perinatal diseases.

  15. High Order Gene-Gene Interactions in Eight Single Nucleotide Polymorphisms of Renin-Angiotensin System Genes for Hypertension Association Study

    Directory of Open Access Journals (Sweden)

    Cheng-Hong Yang

    2015-01-01

    Full Text Available Several single nucleotide polymorphisms (SNPs of renin-angiotensin system (RAS genes are associated with hypertension (HT but most of them are focusing on single locus effects. Here, we introduce an unbalanced function based on multifactor dimensionality reduction (MDR for multiloci genotypes to detect high order gene-gene (SNP-SNP interaction in unbalanced cases and controls of HT data. Eight SNPs of three RAS genes (angiotensinogen, AGT; angiotensin-converting enzyme, ACE; angiotensin II type 1 receptor, AT1R in HT and non-HT subjects were included that showed no significant genotype differences. In 2- to 6-locus models of the SNP-SNP interaction, the SNPs of AGT and ACE genes were associated with hypertension (bootstrapping odds ratio [Boot-OR] = 1.972~3.785; 95%, confidence interval (CI 1.26~6.21; P<0.005. In 7- and 8-locus model, SNP A1166C of AT1R gene is joined to improve the maximum Boot-OR values of 4.050 to 4.483; CI = 2.49 to 7.29; P<1.63E−08. In conclusion, the epistasis networks are identified by eight SNP-SNP interaction models. AGT, ACE, and AT1R genes have overall effects with susceptibility to hypertension, where the SNPs of ACE have a mainly hypertension-associated effect and show an interacting effect to SNPs of AGT and AT1R genes.

  16. Gene-gene and gene-environmental interactions of childhood asthma: a multifactor dimension reduction approach.

    Directory of Open Access Journals (Sweden)

    Ming-Wei Su

    Full Text Available BACKGROUND: The importance of gene-gene and gene-environment interactions on asthma is well documented in literature, but a systematic analysis on the interaction between various genetic and environmental factors is still lacking. METHODOLOGY/PRINCIPAL FINDINGS: We conducted a population-based, case-control study comprised of seventh-grade children from 14 Taiwanese communities. A total of 235 asthmatic cases and 1,310 non-asthmatic controls were selected for DNA collection and genotyping. We examined the gene-gene and gene-environment interactions between 17 single-nucleotide polymorphisms in antioxidative, inflammatory and obesity-related genes, and childhood asthma. Environmental exposures and disease status were obtained from parental questionnaires. The model-free and non-parametrical multifactor dimensionality reduction (MDR method was used for the analysis. A three-way gene-gene interaction was elucidated between the gene coding glutathione S-transferase P (GSTP1, the gene coding interleukin-4 receptor alpha chain (IL4Ra and the gene coding insulin induced gene 2 (INSIG2 on the risk of lifetime asthma. The testing-balanced accuracy on asthma was 57.83% with a cross-validation consistency of 10 out of 10. The interaction of preterm birth and indoor dampness had the highest training-balanced accuracy at 59.09%. Indoor dampness also interacted with many genes, including IL13, beta-2 adrenergic receptor (ADRB2, signal transducer and activator of transcription 6 (STAT6. We also used likelihood ratio tests for interaction and chi-square tests to validate our results and all tests showed statistical significance. CONCLUSIONS/SIGNIFICANCE: The results of this study suggest that GSTP1, INSIG2 and IL4Ra may influence the lifetime asthma susceptibility through gene-gene interactions in schoolchildren. Home dampness combined with each one of the genes STAT6, IL13 and ADRB2 could raise the asthma risk.

  17. Double-bottom chaotic map particle swarm optimization based on chi-square test to determine gene-gene interactions.

    Science.gov (United States)

    Yang, Cheng-Hong; Lin, Yu-Da; Chuang, Li-Yeh; Chang, Hsueh-Wei

    2014-01-01

    Gene-gene interaction studies focus on the investigation of the association between the single nucleotide polymorphisms (SNPs) of genes for disease susceptibility. Statistical methods are widely used to search for a good model of gene-gene interaction for disease analysis, and the previously determined models have successfully explained the effects between SNPs and diseases. However, the huge numbers of potential combinations of SNP genotypes limit the use of statistical methods for analysing high-order interaction, and finding an available high-order model of gene-gene interaction remains a challenge. In this study, an improved particle swarm optimization with double-bottom chaotic maps (DBM-PSO) was applied to assist statistical methods in the analysis of associated variations to disease susceptibility. A big data set was simulated using the published genotype frequencies of 26 SNPs amongst eight genes for breast cancer. Results showed that the proposed DBM-PSO successfully determined two- to six-order models of gene-gene interaction for the risk association with breast cancer (odds ratio > 1.0; P value <0.05). Analysis results supported that the proposed DBM-PSO can identify good models and provide higher chi-square values than conventional PSO. This study indicates that DBM-PSO is a robust and precise algorithm for determination of gene-gene interaction models for breast cancer.

  18. Double-Bottom Chaotic Map Particle Swarm Optimization Based on Chi-Square Test to Determine Gene-Gene Interactions

    Directory of Open Access Journals (Sweden)

    Cheng-Hong Yang

    2014-01-01

    Full Text Available Gene-gene interaction studies focus on the investigation of the association between the single nucleotide polymorphisms (SNPs of genes for disease susceptibility. Statistical methods are widely used to search for a good model of gene-gene interaction for disease analysis, and the previously determined models have successfully explained the effects between SNPs and diseases. However, the huge numbers of potential combinations of SNP genotypes limit the use of statistical methods for analysing high-order interaction, and finding an available high-order model of gene-gene interaction remains a challenge. In this study, an improved particle swarm optimization with double-bottom chaotic maps (DBM-PSO was applied to assist statistical methods in the analysis of associated variations to disease susceptibility. A big data set was simulated using the published genotype frequencies of 26 SNPs amongst eight genes for breast cancer. Results showed that the proposed DBM-PSO successfully determined two- to six-order models of gene-gene interaction for the risk association with breast cancer (odds ratio > 1.0; P value <0.05. Analysis results supported that the proposed DBM-PSO can identify good models and provide higher chi-square values than conventional PSO. This study indicates that DBM-PSO is a robust and precise algorithm for determination of gene-gene interaction models for breast cancer.

  19. Effects related to gene-gene interactions of peroxisome proliferator-activated receptor on essential hypertension

    Institute of Scientific and Technical Information of China (English)

    俞浩

    2013-01-01

    Objective To explore the impact of the gene-gene interaction among the single nucleotide polymorphisms(SNPs) of peroxisome proliferator-activated receptorα/δ/γ on essential hypertension(EH).Methods

  20. Ultrahigh-dimensional variable selection method for whole-genome gene-gene interaction analysis

    Directory of Open Access Journals (Sweden)

    Ueki Masao

    2012-05-01

    Full Text Available Abstract Background Genome-wide gene-gene interaction analysis using single nucleotide polymorphisms (SNPs is an attractive way for identification of genetic components that confers susceptibility of human complex diseases. Individual hypothesis testing for SNP-SNP pairs as in common genome-wide association study (GWAS however involves difficulty in setting overall p-value due to complicated correlation structure, namely, the multiple testing problem that causes unacceptable false negative results. A large number of SNP-SNP pairs than sample size, so-called the large p small n problem, precludes simultaneous analysis using multiple regression. The method that overcomes above issues is thus needed. Results We adopt an up-to-date method for ultrahigh-dimensional variable selection termed the sure independence screening (SIS for appropriate handling of numerous number of SNP-SNP interactions by including them as predictor variables in logistic regression. We propose ranking strategy using promising dummy coding methods and following variable selection procedure in the SIS method suitably modified for gene-gene interaction analysis. We also implemented the procedures in a software program, EPISIS, using the cost-effective GPGPU (General-purpose computing on graphics processing units technology. EPISIS can complete exhaustive search for SNP-SNP interactions in standard GWAS dataset within several hours. The proposed method works successfully in simulation experiments and in application to real WTCCC (Wellcome Trust Case–control Consortium data. Conclusions Based on the machine-learning principle, the proposed method gives powerful and flexible genome-wide search for various patterns of gene-gene interaction.

  1. Polymorphism Interaction Analysis (PIA: a method for investigating complex gene-gene interactions

    Directory of Open Access Journals (Sweden)

    Chanock Stephen J

    2008-03-01

    Full Text Available Abstract Background The risk of common diseases is likely determined by the complex interplay between environmental and genetic factors, including single nucleotide polymorphisms (SNPs. Traditional methods of data analysis are poorly suited for detecting complex interactions due to sparseness of data in high dimensions, which often occurs when data are available for a large number of SNPs for a relatively small number of samples. Validation of associations observed using multiple methods should be implemented to minimize likelihood of false-positive associations. Moreover, high-throughput genotyping methods allow investigators to genotype thousands of SNPs at one time. Investigating associations for each individual SNP or interactions between SNPs using traditional approaches is inefficient and prone to false positives. Results We developed the Polymorphism Interaction Analysis tool (PIA version 2.0 to include different approaches for ranking and scoring SNP combinations, to account for imbalances between case and control ratios, stratify on particular factors, and examine associations of user-defined pathways (based on SNP or gene with case status. PIA v. 2.0 detected 2-SNP interactions as the highest ranking model 77% of the time, using simulated data sets of genetic models of interaction (minor allele frequency = 0.2; heritability = 0.01; N = 1600 generated previously [Velez DR, White BC, Motsinger AA, Bush WS, Ritchie MD, Williams SM, Moore JH: A balanced accuracy function for epistasis modeling in imbalanced datasets using multifactor dimensionality reduction. Genet Epidemiol 2007, 31:306–315.]. Interacting SNPs were detected in both balanced (20 SNPs and imbalanced data (case:control 1:2 and 1:4, 10 SNPs in the context of non-interacting SNPs. Conclusion PIA v. 2.0 is a useful tool for exploring gene*gene or gene*environment interactions and identifying a small number of putative associations which may be investigated further using other

  2. Development and application of an interaction network ontology for literature mining of vaccine-associated gene-gene interactions.

    Science.gov (United States)

    Hur, Junguk; Özgür, Arzucan; Xiang, Zuoshuang; He, Yongqun

    2015-01-01

    Literature mining of gene-gene interactions has been enhanced by ontology-based name classifications. However, in biomedical literature mining, interaction keywords have not been carefully studied and used beyond a collection of keywords. In this study, we report the development of a new Interaction Network Ontology (INO) that classifies >800 interaction keywords and incorporates interaction terms from the PSI Molecular Interactions (PSI-MI) and Gene Ontology (GO). Using INO-based literature mining results, a modified Fisher's exact test was established to analyze significantly over- and under-represented enriched gene-gene interaction types within a specific area. Such a strategy was applied to study the vaccine-mediated gene-gene interactions using all PubMed abstracts. The Vaccine Ontology (VO) and INO were used to support the retrieval of vaccine terms and interaction keywords from the literature. INO is aligned with the Basic Formal Ontology (BFO) and imports terms from 10 other existing ontologies. Current INO includes 540 terms. In terms of interaction-related terms, INO imports and aligns PSI-MI and GO interaction terms and includes over 100 newly generated ontology terms with 'INO_' prefix. A new annotation property, 'has literature mining keywords', was generated to allow the listing of different keywords mapping to the interaction types in INO. Using all PubMed documents published as of 12/31/2013, approximately 266,000 vaccine-associated documents were identified, and a total of 6,116 gene-pairs were associated with at least one INO term. Out of 78 INO interaction terms associated with at least five gene-pairs of the vaccine-associated sub-network, 14 terms were significantly over-represented (i.e., more frequently used) and 17 under-represented based on our modified Fisher's exact test. These over-represented and under-represented terms share some common top-level terms but are distinct at the bottom levels of the INO hierarchy. The analysis of these

  3. Association testing to detect gene-gene interactions on sex chromosomes in trio data

    Directory of Open Access Journals (Sweden)

    Yeonok eLee

    2013-11-01

    Full Text Available Autism Spectrum Disorder (ASD occurs more often among males than females in a 4:1 ratio. Among theories used to explain the causes of ASD, the X chromosome and the Y chromosome theories attribute ASD to X-linked mutation and the male-limited gene expressions on the Y chromosome, respectively. Despite the rationale of the theory, studies have failed to attribute the sex-biased ratio to the significant linkage or association on the regions of interest on X chromosome. We further study the gender biased ratio by examining the possible interaction effects between two genes in the sex chromosomes. We propose a logistic regression model with mixed effects to detect gene-gene interactions on sex chromosomes. We investigated the power and type I error rates of the approach for a range of minor allele frequencies and varying linkage disequilibrium between markers and QTLs. We also evaluated the robustness of the model to population stratification. We applied the model to a trio-family data set with an ASD affected male child to study gene-gene interactions on sex chromosomes.

  4. Gene-Gene Interactions in the Folate Metabolic Pathway and the Risk of Conotruncal Heart Defects

    Directory of Open Access Journals (Sweden)

    Philip J. Lupo

    2010-01-01

    Full Text Available Conotruncal and related heart defects (CTRD are common, complex malformations. Although there are few established risk factors, there is evidence that genetic variation in the folate metabolic pathway influences CTRD risk. This study was undertaken to assess the association between inherited (i.e., case and maternal gene-gene interactions in this pathway and the risk of CTRD. Case-parent triads (n=727, ascertained from the Children's Hospital of Philadelphia, were genotyped for ten functional variants of nine folate metabolic genes. Analyses of inherited genotypes were consistent with the previously reported association between MTHFR A1298C and CTRD (adjusted P=.02, but provided no evidence that CTRD was associated with inherited gene-gene interactions. Analyses of the maternal genotypes provided evidence of a MTHFR C677T/CBS 844ins68 interaction and CTRD risk (unadjusted P=.02. This association is consistent with the effects of this genotype combination on folate-homocysteine biochemistry but remains to be confirmed in independent study populations.

  5. Prediction of drug-drug interactions from chemogenomic and gene-gene interactions and analysis of drug-drug interactions

    OpenAIRE

    2013-01-01

    The interactions between multiple drugs administered to an organism concurrently, whether in the form of synergy or antagonism, are of clinical relevance. Moreover, un-derstanding the mechanisms and nature of drug-drug interactions is of great practical and theoretical interest. Work has previously been done on gene-gene and gene-drug interactions, but the prediction and rationalization of drug-drug interactions from this data is not straightforward. We present a strategy for attacking this p...

  6. A novel fuzzy set based multifactor dimensionality reduction method for detecting gene-gene interaction.

    Science.gov (United States)

    Jung, Hye-Young; Leem, Sangseob; Lee, Sungyoung; Park, Taesung

    2016-12-01

    Gene-gene interaction (GGI) is one of the most popular approaches for finding the missing heritability of common complex traits in genetic association studies. The multifactor dimensionality reduction (MDR) method has been widely studied for detecting GGIs. In order to identify the best interaction model associated with disease susceptibility, MDR compares all possible genotype combinations in terms of their predictability of disease status from a simple binary high(H) and low(L) risk classification. However, this simple binary classification does not reflect the uncertainty of H/L classification. We regard classifying H/L as equivalent to defining the degree of membership of two risk groups H/L. By adopting the fuzzy set theory, we propose Fuzzy MDR which takes into account the uncertainty of H/L classification. Fuzzy MDR allows the possibility of partial membership of H/L through a membership function which transforms the degree of uncertainty into a [0,1] scale. The best genotype combinations can be selected which maximizes a new fuzzy set based accuracy measure. Two simulation studies are conducted to compare the power of the proposed Fuzzy MDR with that of MDR. Our results show that Fuzzy MDR has higher power than MDR. We illustrate the proposed Fuzzy MDR by analysing bipolar disorder (BD) trait of the WTCCC dataset to detect GGI associated with BD. We propose a novel Fuzzy MDR method to detect gene-gene interaction by taking into account the uncertainly of H/L classification and show that it has higher power than MDR. Fuzzy MDR can be easily extended to handle continuous phenotypes as well. The program written in R for the proposed Fuzzy MDR is available at https://statgen.snu.ac.kr/software/FuzzyMDR. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Post genome-wide association studies of novel genes associated with type 2 diabetes show gene-gene interaction and high predictive value.

    Directory of Open Access Journals (Sweden)

    Stéphane Cauchi

    Full Text Available BACKGROUND: Recently, several Genome Wide Association (GWA studies in populations of European descent have identified and validated novel single nucleotide polymorphisms (SNPs, highly associated with type 2 diabetes (T2D. Our aims were to validate these markers in other European and non-European populations, then to assess their combined effect in a large French study comparing T2D and normal glucose tolerant (NGT individuals. METHODOLOGY/PRINCIPAL FINDINGS: In the same French population analyzed in our previous GWA study (3,295 T2D and 3,595 NGT, strong associations with T2D were found for CDKAL1 (OR(rs7756992 = 1.30[1.19-1.42], P = 2.3x10(-9, CDKN2A/2B (OR(rs10811661 = 0.74[0.66-0.82], P = 3.5x10(-8 and more modestly for IGFBP2 (OR(rs1470579 = 1.17[1.07-1.27], P = 0.0003 SNPs. These results were replicated in both Israeli Ashkenazi (577 T2D and 552 NGT and Austrian (504 T2D and 753 NGT populations (except for CDKAL1 but not in the Moroccan population (521 T2D and 423 NGT. In the overall group of French subjects (4,232 T2D and 4,595 NGT, IGFBP2 and CXCR4 synergistically interacted with (LOC38776, SLC30A8, HHEX and (NGN3, CDKN2A/2B, respectively, encoding for proteins presumably regulating pancreatic endocrine cell development and function. The T2D risk increased strongly when risk alleles, including the previously discovered T2D-associated TCF7L2 rs7903146 SNP, were combined (8.68-fold for the 14% of French individuals carrying 18 to 30 risk alleles with an allelic OR of 1.24. With an area under the ROC curve of 0.86, only 15 novel loci were necessary to discriminate French individuals susceptible to develop T2D. CONCLUSIONS/SIGNIFICANCE: In addition to TCF7L2, SLC30A8 and HHEX, initially identified by the French GWA scan, CDKAL1, IGFBP2 and CDKN2A/2B strongly associate with T2D in French individuals, and mostly in populations of Central European descent but not in Moroccan subjects. Genes expressed in the pancreas interact together and their

  8. Spatially Uniform ReliefF (SURF for computationally-efficient filtering of gene-gene interactions

    Directory of Open Access Journals (Sweden)

    Greene Casey S

    2009-09-01

    Full Text Available Abstract Background Genome-wide association studies are becoming the de facto standard in the genetic analysis of common human diseases. Given the complexity and robustness of biological networks such diseases are unlikely to be the result of single points of failure but instead likely arise from the joint failure of two or more interacting components. The hope in genome-wide screens is that these points of failure can be linked to single nucleotide polymorphisms (SNPs which confer disease susceptibility. Detecting interacting variants that lead to disease in the absence of single-gene effects is difficult however, and methods to exhaustively analyze sets of these variants for interactions are combinatorial in nature thus making them computationally infeasible. Efficient algorithms which can detect interacting SNPs are needed. ReliefF is one such promising algorithm, although it has low success rate for noisy datasets when the interaction effect is small. ReliefF has been paired with an iterative approach, Tuned ReliefF (TuRF, which improves the estimation of weights in noisy data but does not fundamentally change the underlying ReliefF algorithm. To improve the sensitivity of studies using these methods to detect small effects we introduce Spatially Uniform ReliefF (SURF. Results SURF's ability to detect interactions in this domain is significantly greater than that of ReliefF. Similarly SURF, in combination with the TuRF strategy significantly outperforms TuRF alone for SNP selection under an epistasis model. It is important to note that this success rate increase does not require an increase in algorithmic complexity and allows for increased success rate, even with the removal of a nuisance parameter from the algorithm. Conclusion Researchers performing genetic association studies and aiming to discover gene-gene interactions associated with increased disease susceptibility should use SURF in place of ReliefF. For instance, SURF should be

  9. Literature Mining and Ontology based Analysis of Host-Brucella Gene-Gene Interaction Network.

    Science.gov (United States)

    Karadeniz, İlknur; Hur, Junguk; He, Yongqun; Özgür, Arzucan

    2015-01-01

    Brucella is an intracellular bacterium that causes chronic brucellosis in humans and various mammals. The identification of host-Brucella interaction is crucial to understand host immunity against Brucella infection and Brucella pathogenesis against host immune responses. Most of the information about the inter-species interactions between host and Brucella genes is only available in the text of the scientific publications. Many text-mining systems for extracting gene and protein interactions have been proposed. However, only a few of them have been designed by considering the peculiarities of host-pathogen interactions. In this paper, we used a text mining approach for extracting host-Brucella gene-gene interactions from the abstracts of articles in PubMed. The gene-gene interactions here represent the interactions between genes and/or gene products (e.g., proteins). The SciMiner tool, originally designed for detecting mammalian gene/protein names in text, was extended to identify host and Brucella gene/protein names in the abstracts. Next, sentence-level and abstract-level co-occurrence based approaches, as well as sentence-level machine learning based methods, originally designed for extracting intra-species gene interactions, were utilized to extract the interactions among the identified host and Brucella genes. The extracted interactions were manually evaluated. A total of 46 host-Brucella gene interactions were identified and represented as an interaction network. Twenty four of these interactions were identified from sentence-level processing. Twenty two additional interactions were identified when abstract-level processing was performed. The Interaction Network Ontology (INO) was used to represent the identified interaction types at a hierarchical ontology structure. Ontological modeling of specific gene-gene interactions demonstrates that host-pathogen gene-gene interactions occur at experimental conditions which can be ontologically represented. Our

  10. Characterizing gene-gene interactions in a statistical epistasis network of twelve candidate genes for obesity.

    Science.gov (United States)

    De, Rishika; Hu, Ting; Moore, Jason H; Gilbert-Diamond, Diane

    2015-01-01

    Recent findings have reemphasized the importance of epistasis, or gene-gene interactions, as a contributing factor to the unexplained heritability of obesity. Network-based methods such as statistical epistasis networks (SEN), present an intuitive framework to address the computational challenge of studying pairwise interactions between thousands of genetic variants. In this study, we aimed to analyze pairwise interactions that are associated with Body Mass Index (BMI) between SNPs from twelve genes robustly associated with obesity (BDNF, ETV5, FAIM2, FTO, GNPDA2, KCTD15, MC4R, MTCH2, NEGR1, SEC16B, SH2B1, and TMEM18). We used information gain measures to identify all SNP-SNP interactions among and between these genes that were related to obesity (BMI > 30 kg/m(2)) within the Framingham Heart Study Cohort; interactions exceeding a certain threshold were used to build an SEN. We also quantified whether interactions tend to occur more between SNPs from the same gene (dyadicity) or between SNPs from different genes (heterophilicity). We identified a highly connected SEN of 709 SNPs and 1241 SNP-SNP interactions. Combining the SEN framework with dyadicity and heterophilicity analyses, we found 1 dyadic gene (TMEM18, P-value = 0.047) and 3 heterophilic genes (KCTD15, P-value = 0.045; SH2B1, P-value = 0.003; and TMEM18, P-value = 0.001). We also identified a lncRNA SNP (rs4358154) as a key node within the SEN using multiple network measures. This study presents an analytical framework to characterize the global landscape of genetic interactions from genome-wide arrays and also to discover nodes of potential biological significance within the identified network.

  11. A Review for Detecting Gene-Gene Interactions Using Machine Learning Methods in Genetic Epidemiology

    Directory of Open Access Journals (Sweden)

    Ching Lee Koo

    2013-01-01

    Full Text Available Recently, the greatest statistical computational challenge in genetic epidemiology is to identify and characterize the genes that interact with other genes and environment factors that bring the effect on complex multifactorial disease. These gene-gene interactions are also denoted as epitasis in which this phenomenon cannot be solved by traditional statistical method due to the high dimensionality of the data and the occurrence of multiple polymorphism. Hence, there are several machine learning methods to solve such problems by identifying such susceptibility gene which are neural networks (NNs, support vector machine (SVM, and random forests (RFs in such common and multifactorial disease. This paper gives an overview on machine learning methods, describing the methodology of each machine learning methods and its application in detecting gene-gene and gene-environment interactions. Lastly, this paper discussed each machine learning method and presents the strengths and weaknesses of each machine learning method in detecting gene-gene interactions in complex human disease.

  12. Genome-wide search for gene-gene interactions in colorectal cancer.

    Directory of Open Access Journals (Sweden)

    Shuo Jiao

    Full Text Available Genome-wide association studies (GWAS have successfully identified a number of single-nucleotide polymorphisms (SNPs associated with colorectal cancer (CRC risk. However, these susceptibility loci known today explain only a small fraction of the genetic risk. Gene-gene interaction (GxG is considered to be one source of the missing heritability. To address this, we performed a genome-wide search for pair-wise GxG associated with CRC risk using 8,380 cases and 10,558 controls in the discovery phase and 2,527 cases and 2,658 controls in the replication phase. We developed a simple, but powerful method for testing interaction, which we term the Average Risk Due to Interaction (ARDI. With this method, we conducted a genome-wide search to identify SNPs showing evidence for GxG with previously identified CRC susceptibility loci from 14 independent regions. We also conducted a genome-wide search for GxG using the marginal association screening and examining interaction among SNPs that pass the screening threshold (p<10(-4. For the known locus rs10795668 (10p14, we found an interacting SNP rs367615 (5q21 with replication p = 0.01 and combined p = 4.19×10(-8. Among the top marginal SNPs after LD pruning (n = 163, we identified an interaction between rs1571218 (20p12.3 and rs10879357 (12q21.1 (nominal combined p = 2.51×10(-6; Bonferroni adjusted p = 0.03. Our study represents the first comprehensive search for GxG in CRC, and our results may provide new insight into the genetic etiology of CRC.

  13. Molecular Basis of Gene-Gene Interaction: Cyclic Cross-Regulation of Gene Expression and Post-GWAS Gene-Gene Interaction Involved in Atrial Fibrillation.

    Directory of Open Access Journals (Sweden)

    Yufeng Huang

    2015-08-01

    Full Text Available Atrial fibrillation (AF is the most common cardiac arrhythmia at the clinic. Recent GWAS identified several variants associated with AF, but they account for <10% of heritability. Gene-gene interaction is assumed to account for a significant portion of missing heritability. Among GWAS loci for AF, only three were replicated in the Chinese Han population, including SNP rs2106261 (G/A substitution in ZFHX3, rs2200733 (C/T substitution near PITX2c, and rs3807989 (A/G substitution in CAV1. Thus, we analyzed the interaction among these three AF loci. We demonstrated significant interaction between rs2106261 and rs2200733 in three independent populations and combined population with 2,020 cases/5,315 controls. Compared to non-risk genotype GGCC, two-locus risk genotype AATT showed the highest odds ratio in three independent populations and the combined population (OR=5.36 (95% CI 3.87-7.43, P=8.00×10-24. The OR of 5.36 for AATT was significantly higher than the combined OR of 3.31 for both GGTT and AACC, suggesting a synergistic interaction between rs2106261 and rs2200733. Relative excess risk due to interaction (RERI analysis also revealed significant interaction between rs2106261 and rs2200733 when exposed two copies of risk alleles (RERI=2.87, P<1.00×10-4 or exposed to one additional copy of risk allele (RERI=1.29, P<1.00×10-4. The INTERSNP program identified significant genotypic interaction between rs2106261 and rs2200733 under an additive by additive model (OR=0.85, 95% CI: 0.74-0.97, P=0.02. Mechanistically, PITX2c negatively regulates expression of miR-1, which negatively regulates expression of ZFHX3, resulting in a positive regulation of ZFHX3 by PITX2c; ZFHX3 positively regulates expression of PITX2C, resulting in a cyclic loop of cross-regulation between ZFHX3 and PITX2c. Both ZFHX3 and PITX2c regulate expression of NPPA, TBX5 and NKX2.5. These results suggest that cyclic cross-regulation of gene expression is a molecular basis for gene-gene

  14. Contributions of IBD5, IL23R, ATG16L1, and NOD2 to Crohn's disease risk in a population-based case-control study: evidence of gene-gene interactions.

    Science.gov (United States)

    Okazaki, Toshihiko; Wang, Ming-Hsi; Rawsthorne, Patricia; Sargent, Michael; Datta, Lisa Wu; Shugart, Yin Yao; Bernstein, Charles N; Brant, Steven R

    2008-11-01

    IBD5, IL23R, and ATG16L1 genetic variations are established Crohn's disease (CD) risks alleles. We evaluated these in a population-based case-control study within a cohort to determine their penetrance, population attributable risk, independence, and relationship to other established CD risk factors, including NOD2. DNA from 213 CD, 118 [corrected] ulcerative colitis, and 315 [corrected] healthy control subjects from the population based University of Manitoba IBD Research Registry were genotyped for IBD5 and IL23R single-nucleotide polymorphisms (SNPs),and for the Thr 300Ala ATG16L1 SNP. Univariate and multivariate analyses were performed for these and nongenetic risk factors.We introduce multidimensionality reduction (MDR) to explore gene– gene interactions. ATG16L1, IBD5, and IL23R SNPs were significantly associated with CD. Multivariate analysis showed independent CD association for carriers of ATG16L1 (odds ratio [OR] = 1.8, 95% confidence interval [CI] 1.09-3.24), IBD5-IGR2230 (OR = 2.16, 95% CI 1.30-3.59), and IL23R-rs10889677 (OR = 2.13, 95% CI 1.39-3.28) while retaining association for NOD2 mutation carriers (OR = 4.45, 95% CI 2.68-7.38), IBD family history (OR = 2.75, 95% CI 1.42-5.31), tobacco (OR = 2.06, 95% CI 1.35-3.14), and Jewish ethnicity (OR = 20.1, 95% CI 2.16-186.8). IL23R minor variants for Arg381Gln and Intron 6 rs7517848 showed independent, CD protection and 3' untranslated variant rs108896778 showed risk. MDR analysis suggested an interaction between IBD5, ATG16L1, and IL23R risk alleles. Penetrance values for ATG16L1 and IBD5 were 0.27% for heterozygotes, and 0.35% and 0.44%, respectively, for homozygotes. IL23R rs108896778 penetrance was 0.37%. A population-based analysis of CD risk factors is useful for characterizing the epidemiology of multiple CD genetic and nongenetic risk factors. Gene-gene interactions are likely, but require further evaluation in large population-based cohorts.

  15. Gene-gene and gene-sex epistatic interactions of DNMT1, DNMT3A and DNMT3B in autoimmune thyroid disease.

    Science.gov (United States)

    Cai, Tian-Tian; Zhang, Jian; Wang, Xuan; Song, Rong-Hua; Qin, Qiu; Muhali, Fatuma-Said; Zhou, Jiao-Zhen; Xu, Jian; Zhang, Jin-An

    2016-07-30

    The aim of this study was to investigate the associations of DNA methyltransferases (DNMTs) polymorphisms with susceptibility to autoimmune thyroid diseases (AITDs) and to test gene-gene/gene-sex epistasis interactions. Eight single-nucleotide polymorphisms (SNPs) in DNMT1, DNMT3A and DNMT3B were selected and genotyped by multiplex polymerase chain reaction combined with ligase detection reaction method (PCR-LDR). A total of 685 Graves' disease (GD) patients, 353 Hashimoto's thyroiditis (HT) patients and 909 healthy controls were included in the final analysis. Epistasis was tested by additive model, multiplicative model and general multifactor dimensionality reduction (general MDR). Rs2424913 (DNMT3B) and rs2228611 (DNMT1) were associated with susceptibility to AITD and GD in the dominant and overdominant model, respectively (rs2424913: P=0.009 for AITD, P=0.0041 for GD; rs2228611: P=0.035 for AITD, P=0.043 for GD). Multiplicative and multiple high dimensional gene-gene or gene-sex interactions were also observed in this study. We have found evidence for a potential role of rs2424913 (DNMT3B) and rs2228611 (DNMT1) in AITD susceptibility and identified novel gene-gene/gene-sex interactions in AITD. Our study may highlight sex and genes of DNMTs family as contributors to the pathogenesis of AITD.

  16. Gene-Gene-Environment Interactions of Serotonin Transporter, Monoamine Oxidase A and Childhood Maltreatment Predict Aggressive Behavior in Chinese Adolescents

    Science.gov (United States)

    Zhang, Yun; Ming, Qing-sen; Yi, Jin-yao; Wang, Xiang; Chai, Qiao-lian; Yao, Shu-qiao

    2017-01-01

    Gene-environment interactions that moderate aggressive behavior have been identified independently in the serotonin transporter (5-HTT) gene and monoamine oxidase A gene (MAOA). The aim of the present study was to investigate epistasis interactions between MAOA-variable number tandem repeat (VNTR), 5-HTTlinked polymorphism (LPR) and child abuse and the effects of these on aggressive tendencies in a group of otherwise healthy adolescents. A group of 546 Chinese male adolescents completed the Child Trauma Questionnaire and Youth self-report of the Child Behavior Checklist. Buccal cells were collected for DNA analysis. The effects of childhood abuse, MAOA-VNTR, 5-HTTLPR genotypes and their interactive gene-gene-environmental effects on aggressive behavior were analyzed using a linear regression model. The effect of child maltreatment was significant, and a three-way interaction among MAOA-VNTR, 5-HTTLPR and sexual abuse (SA) relating to aggressive behaviors was identified. Chinese male adolescents with high expression of the MAOA-VNTR allele and 5-HTTLPR “SS” genotype exhibited the highest aggression tendencies with an increase in SA during childhood. The findings reported support aggression being a complex behavior involving the synergistic effects of gene-gene-environment interactions. PMID:28203149

  17. Perinatal Gene-Gene and Gene-Environment Interactions on IgE Production and Asthma Development

    Directory of Open Access Journals (Sweden)

    Jen-Chieh Chang

    2012-01-01

    Full Text Available Atopic asthma is a complex disease associated with IgE-mediated immune reactions. Numerous genome-wide studies identified more than 100 genes in 22 chromosomes associated with atopic asthma, and different genetic backgrounds in different environments could modulate susceptibility to atopic asthma. Current knowledge emphasizes the effect of tobacco smoke on the development of childhood asthma. This suggests that asthma, although heritable, is significantly affected by gene-gene and gene-environment interactions. Evidence has recently shown that molecular mechanism of a complex disease may be limited to not only DNA sequence differences, but also gene-environmental interactions for epigenetic difference. This paper reviews and summarizes how gene-gene and gene-environment interactions affect IgE production and the development of atopic asthma in prenatal and childhood stages. Based on the mechanisms responsible for perinatal gene-environment interactions on IgE production and development of asthma, we formulate several potential strategies to prevent the development of asthma in the perinatal stage.

  18. A gene-gene interaction between polymorphisms in the OCT2 and MATE1 genes influences the renal clearance of metformin

    DEFF Research Database (Denmark)

    Hougaard Christensen, Mette Marie; Pedersen, Rasmus Steen; Stage, Tore Bjerregaard;

    2013-01-01

    The aim of this study was to determine the association between the renal clearance (CL(renal)) of metformin in healthy Caucasian volunteers and the single-nucleotide polymorphism (SNP) c.808G>T (rs316019) in OCT2 as well as the relevance of the gene-gene interactions between this SNP and (a...

  19. An empirical fuzzy multifactor dimensionality reduction method for detecting gene-gene interactions.

    Science.gov (United States)

    Leem, Sangseob; Park, Taesung

    2017-03-14

    Detection of gene-gene interaction (GGI) is a key challenge towards solving the problem of missing heritability in genetics. The multifactor dimensionality reduction (MDR) method has been widely studied for detecting GGIs. MDR reduces the dimensionality of multi-factor by means of binary classification into high-risk (H) or low-risk (L) groups. Unfortunately, this simple binary classification does not reflect the uncertainty of H/L classification. Thus, we proposed Fuzzy MDR to overcome limitations of binary classification by introducing the degree of membership of two fuzzy sets H/L. While Fuzzy MDR demonstrated higher power than that of MDR, its performance is highly dependent on the several tuning parameters. In real applications, it is not easy to choose appropriate tuning parameter values. In this work, we propose an empirical fuzzy MDR (EF-MDR) which does not require specifying tuning parameters values. Here, we propose an empirical approach to estimating the membership degree that can be directly estimated from the data. In EF-MDR, the membership degree is estimated by the maximum likelihood estimator of the proportion of cases(controls) in each genotype combination. We also show that the balanced accuracy measure derived from this new membership function is a linear function of the standard chi-square statistics. This relationship allows us to perform the standard significance test using p-values in the MDR framework without permutation. Through two simulation studies, the power of the proposed EF-MDR is shown to be higher than those of MDR and Fuzzy MDR. We illustrate the proposed EF-MDR by analyzing Crohn's disease (CD) and bipolar disorder (BD) in the Wellcome Trust Case Control Consortium (WTCCC) dataset. We propose an empirical Fuzzy MDR for detecting GGI using the maximum likelihood of the proportion of cases(controls) as the membership degree of the genotype combination. The program written in R for EF-MDR is available at http://statgen.snu.ac.kr/software/EF-MDR .

  20. Interactive Naive Bayesian network: A new approach of constructing gene-gene interaction network for cancer classification.

    Science.gov (United States)

    Tian, Xue W; Lim, Joon S

    2015-01-01

    Naive Bayesian (NB) network classifier is a simple and well-known type of classifier, which can be easily induced from a DNA microarray data set. However, a strong conditional independence assumption of NB network sometimes can lead to weak classification performance. In this paper, we propose a new approach of interactive naive Bayesian (INB) network to weaken the conditional independence of NB network and classify cancers using DNA microarray data set. We selected the differently expressed genes (DEGs) to reduce the dimension of the microarray data set. Then, an interactive parent which has the biggest influence among all DEGs is searched for each DEG. And then we calculate a weight to represent the interactive relationship between a DEG and its parent. Finally, the gene-gene interaction network is constructed. We experimentally test the INB network in terms of classification accuracy using leukemia and colon DNA microarray data sets, then we compare it with the NB network. The INB network can get higher classification accuracies than NB network. And INB network can show the gene-gene interactions visually.

  1. Discovery of gene-gene interactions across multiple independent data sets of late onset Alzheimer disease from the Alzheimer Disease Genetics Consortium.

    Science.gov (United States)

    Hohman, Timothy J; Bush, William S; Jiang, Lan; Brown-Gentry, Kristin D; Torstenson, Eric S; Dudek, Scott M; Mukherjee, Shubhabrata; Naj, Adam; Kunkle, Brian W; Ritchie, Marylyn D; Martin, Eden R; Schellenberg, Gerard D; Mayeux, Richard; Farrer, Lindsay A; Pericak-Vance, Margaret A; Haines, Jonathan L; Thornton-Wells, Tricia A

    2016-02-01

    Late-onset Alzheimer disease (AD) has a complex genetic etiology, involving locus heterogeneity, polygenic inheritance, and gene-gene interactions; however, the investigation of interactions in recent genome-wide association studies has been limited. We used a biological knowledge-driven approach to evaluate gene-gene interactions for consistency across 13 data sets from the Alzheimer Disease Genetics Consortium. Fifteen single nucleotide polymorphism (SNP)-SNP pairs within 3 gene-gene combinations were identified: SIRT1 × ABCB1, PSAP × PEBP4, and GRIN2B × ADRA1A. In addition, we extend a previously identified interaction from an endophenotype analysis between RYR3 × CACNA1C. Finally, post hoc gene expression analyses of the implicated SNPs further implicate SIRT1 and ABCB1, and implicate CDH23 which was most recently identified as an AD risk locus in an epigenetic analysis of AD. The observed interactions in this article highlight ways in which genotypic variation related to disease may depend on the genetic context in which it occurs. Further, our results highlight the utility of evaluating genetic interactions to explain additional variance in AD risk and identify novel molecular mechanisms of AD pathogenesis.

  2. GSNO Reductase and β2 Adrenergic Receptor Gene-gene Interaction: Bronchodilator Responsiveness to Albuterol

    Science.gov (United States)

    Choudhry, Shweta; Que, Loretta G.; Yang, Zhonghui; Liu, Limin; Eng, Celeste; Kim, Sung O.; Kumar, Gunjan; Thyne, Shannon; Chapela, Rocio; Rodriguez-Santana, Jose R.; Rodriguez-Cintron, William; Avila, Pedro C.; Stamler, Jonathan S.; Burchard, Esteban G.

    2010-01-01

    Background Short-acting inhaled β2-agonists such as albuterol are used for bronchodilation and are the mainstay of asthma treatment worldwide. There is significant variation in bronchodilator responsiveness to albuterol not only between individuals but also across racial/ethnic groups. The β2-adrenergic receptor (β2AR) is the target for β2-agonist drugs. The enzyme S-nitrosoglutathione reductase (GSNOR), which regulates levels of the endogenous bronchodilator S-nitrosoglutathione, has been shown to modulate the response to β2-agonists. Objective We hypothesized that there are pharmacogenetic interactions between GSNOR and β2AR gene variants which are associated with variable response to albuterol. Methods We performed family-based analyses to test for association between GSNOR gene variants and asthma and related phenotypes in 609 Puerto Rican and Mexican families with asthma. In addition, we tested these subjects for pharmacogenetic interaction between GSNOR and β2AR gene variants and responsiveness to albuterol using linear regression. Cell transfection experiments were performed to test the potential effect of the GSNOR gene variants. Results Among Puerto Ricans, several GSNOR SNPs and a haplotype in the 3′UTR were significantly associated with increased risk for asthma and lower bronchodilator responsiveness (p = 0.04 to 0.007). The GSNOR risk haplotype affects expression of GSNOR mRNA and protein, suggesting a gain of function. Furthermore, gene-gene interaction analysis provided evidence of pharmacogenetic interaction between GSNOR and β2AR gene variants and the response to albuterol in Puerto Rican (p = 0.03), Mexican (p = 0.15) and combined Puerto Rican and Mexican asthmatics (p = 0.003). Specifically, GSNOR+17059*β2AR+46 genotype combinations (TG+GG*AG and TG+GG*GG) were associated with lower bronchodilator response. Conclusion Genotyping of GSNOR and β2AR genes may be a useful in identifying Latino subjects, who might benefit from adjuvant

  3. The gene-gene interaction of INSIG-SCAP-SREBP pathway on the risk of obesity in Chinese children.

    Science.gov (United States)

    Liu, Fang-Hong; Song, Jie-Yun; Shang, Xiao-Rui; Meng, Xiang-Rui; Ma, Jun; Wang, Hai-Jun

    2014-01-01

    Childhood obesity has become a global public health problem in recent years. This study aimed to explore the association of genetic variants in INSIG-SCAP-SREBP pathway with obesity in Chinese children. A case-control study was conducted, including 705 obese cases and 1,325 nonobese controls. We genotyped 15 single nucleotide polymorphisms (SNPs) of five genes in INSIG-SCAP-SREBP pathway, including insulin induced gene 1 (INSIG1), insulin induced gene 2 (INSIG2), SREBP cleavage-activating protein gene (SCAP), sterol regulatory element binding protein gene 1 (SREBP1), and sterol regulatory element binding protein gene 2 (SREBP2). We used generalized multifactor dimensionality reduction (GMDR) and logistic regression to investigate gene-gene interactions. Single polymorphism analyses showed that SCAP rs12487736 and rs12490383 were nominally associated with obesity. We identified a 3-locus interaction on obesity in GMDR analyses (P = 0.001), involving 3 genetic variants of INSIG2, SCAP, and SREBP2. The individuals in high-risk group of the 3-locus combinations had a 79.9% increased risk of obesity compared with those in low-risk group (OR = 1.799, 95% CI: 1.475-2.193, P = 6.61 × 10(-9)). We identified interaction of three genes in INSIG-SCAP-SREBP pathway on risk of obesity, revealing that these genes affect obesity more likely through a complex interaction pattern than single gene effect.

  4. Genotype-based association models of complex diseases to detect gene-gene and gene-environment interactions.

    Science.gov (United States)

    Lobach, Iryna; Fan, Ruzong; Manga, Prashiela

    A central problem in genetic epidemiology is to identify and rank genetic markers involved in a disease. Complex diseases, such as cancer, hypertension, diabetes, are thought to be caused by an interaction of a panel of genetic factors, that can be identified by markers, which modulate environmental factors. Moreover, the effect of each genetic marker may be small. Hence, the association signal may be missed unless a large sample is considered, or a priori biomedical data are used. Recent advances generated a vast variety of a priori information, including linkage maps and information about gene regulatory dependence assembled into curated pathway databases. We propose a genotype-based approach that takes into account linkage disequilibrium (LD) information between genetic markers that are in moderate LD while modeling gene-gene and gene-environment interactions. A major advantage of our method is that the observed genetic information enters a model directly thus eliminating the need to estimate haplotype-phase. Our approach results in an algorithm that is inexpensive computationally and does not suffer from bias induced by haplotype-phase ambiguity. We investigated our model in a series of simulation experiments and demonstrated that the proposed approach results in estimates that are nearly unbiased and have small variability. We applied our method to the analysis of data from a melanoma case-control study and investigated interaction between a set of pigmentation genes and environmental factors defined by age and gender. Furthermore, an application of our method is demonstrated using a study of Alcohol Dependence.

  5. Use of Information Measures and Their Approximations to Detect Predictive Gene-Gene Interaction

    Directory of Open Access Journals (Sweden)

    Jan Mielniczuk

    2017-01-01

    Full Text Available We reconsider the properties and relationships of the interaction information and its modified versions in the context of detecting the interaction of two SNPs for the prediction of a binary outcome when interaction information is positive. This property is called predictive interaction, and we state some new sufficient conditions for it to hold true. We also study chi square approximations to these measures. It is argued that interaction information is a different and sometimes more natural measure of interaction than the logistic interaction parameter especially when SNPs are dependent. We introduce a novel measure of predictive interaction based on interaction information and its modified version. In numerical experiments, which use copulas to model dependence, we study examples when the logistic interaction parameter is zero or close to zero for which predictive interaction is detected by the new measure, while it remains undetected by the likelihood ratio test.

  6. Knowledge-driven analysis identifies a gene-gene interaction affecting high-density lipoprotein cholesterol levels in multi-ethnic populations.

    Science.gov (United States)

    Ma, Li; Brautbar, Ariel; Boerwinkle, Eric; Sing, Charles F; Clark, Andrew G; Keinan, Alon

    2012-01-01

    Total cholesterol, low-density lipoprotein cholesterol, triglyceride, and high-density lipoprotein cholesterol (HDL-C) levels are among the most important risk factors for coronary artery disease. We tested for gene-gene interactions affecting the level of these four lipids based on prior knowledge of established genome-wide association study (GWAS) hits, protein-protein interactions, and pathway information. Using genotype data from 9,713 European Americans from the Atherosclerosis Risk in Communities (ARIC) study, we identified an interaction between HMGCR and a locus near LIPC in their effect on HDL-C levels (Bonferroni corrected P(c) = 0.002). Using an adaptive locus-based validation procedure, we successfully validated this gene-gene interaction in the European American cohorts from the Framingham Heart Study (P(c) = 0.002) and the Multi-Ethnic Study of Atherosclerosis (MESA; P(c) = 0.006). The interaction between these two loci is also significant in the African American sample from ARIC (P(c) = 0.004) and in the Hispanic American sample from MESA (P(c) = 0.04). Both HMGCR and LIPC are involved in the metabolism of lipids, and genome-wide association studies have previously identified LIPC as associated with levels of HDL-C. However, the effect on HDL-C of the novel gene-gene interaction reported here is twice as pronounced as that predicted by the sum of the marginal effects of the two loci. In conclusion, based on a knowledge-driven analysis of epistasis, together with a new locus-based validation method, we successfully identified and validated an interaction affecting a complex trait in multi-ethnic populations.

  7. A non-parametric approach for detecting gene-gene interactions associated with age-at-onset outcomes.

    Science.gov (United States)

    Li, Ming; Gardiner, Joseph C; Breslau, Naomi; Anthony, James C; Lu, Qing

    2014-07-01

    Cox-regression-based methods have been commonly used for the analyses of survival outcomes, such as age-at-disease-onset. These methods generally assume the hazard functions are proportional among various risk groups. However, such an assumption may not be valid in genetic association studies, especially when complex interactions are involved. In addition, genetic association studies commonly adopt case-control designs. Direct use of Cox regression to case-control data may yield biased estimators and incorrect statistical inference. We propose a non-parametric approach, the weighted Nelson-Aalen (WNA) approach, for detecting genetic variants that are associated with age-dependent outcomes. The proposed approach can be directly applied to prospective cohort studies, and can be easily extended for population-based case-control studies. Moreover, it does not rely on any assumptions of the disease inheritance models, and is able to capture high-order gene-gene interactions. Through simulations, we show the proposed approach outperforms Cox-regression-based methods in various scenarios. We also conduct an empirical study of progression of nicotine dependence by applying the WNA approach to three independent datasets from the Study of Addiction: Genetics and Environment. In the initial dataset, two SNPs, rs6570989 and rs2930357, located in genes GRIK2 and CSMD1, are found to be significantly associated with the progression of nicotine dependence (ND). The joint association is further replicated in two independent datasets. Further analysis suggests that these two genes may interact and be associated with the progression of ND. As demonstrated by the simulation studies and real data analysis, the proposed approach provides an efficient tool for detecting genetic interactions associated with age-at-onset outcomes.

  8. To control false positives in gene-gene interaction analysis: two novel conditional entropy-based approaches.

    Directory of Open Access Journals (Sweden)

    Xiaoyu Zuo

    Full Text Available Genome-wide analysis of gene-gene interactions has been recognized as a powerful avenue to identify the missing genetic components that can not be detected by using current single-point association analysis. Recently, several model-free methods (e.g. the commonly used information based metrics and several logistic regression-based metrics were developed for detecting non-linear dependence between genetic loci, but they are potentially at the risk of inflated false positive error, in particular when the main effects at one or both loci are salient. In this study, we proposed two conditional entropy-based metrics to challenge this limitation. Extensive simulations demonstrated that the two proposed metrics, provided the disease is rare, could maintain consistently correct false positive rate. In the scenarios for a common disease, our proposed metrics achieved better or comparable control of false positive error, compared to four previously proposed model-free metrics. In terms of power, our methods outperformed several competing metrics in a range of common disease models. Furthermore, in real data analyses, both metrics succeeded in detecting interactions and were competitive with the originally reported results or the logistic regression approaches. In conclusion, the proposed conditional entropy-based metrics are promising as alternatives to current model-based approaches for detecting genuine epistatic effects.

  9. HSD3B and gene-gene interactions in a pathway-based analysis of genetic susceptibility to bladder cancer.

    Directory of Open Access Journals (Sweden)

    Angeline S Andrew

    Full Text Available Bladder cancer is the 4(th most common cancer among men in the U.S. We analyzed variant genotypes hypothesized to modify major biological processes involved in bladder carcinogenesis, including hormone regulation, apoptosis, DNA repair, immune surveillance, metabolism, proliferation, and telomere maintenance. Logistic regression was used to assess the relationship between genetic variation affecting these processes and susceptibility in 563 genotyped urothelial cell carcinoma cases and 863 controls enrolled in a case-control study of incident bladder cancer conducted in New Hampshire, U.S. We evaluated gene-gene interactions using Multifactor Dimensionality Reduction (MDR and Statistical Epistasis Network analysis. The 3'UTR flanking variant form of the hormone regulation gene HSD3B2 was associated with increased bladder cancer risk in the New Hampshire population (adjusted OR 1.85 95%CI 1.31-2.62. This finding was successfully replicated in the Texas Bladder Cancer Study with 957 controls, 497 cases (adjusted OR 3.66 95%CI 1.06-12.63. The effect of this prevalent SNP was stronger among males (OR 2.13 95%CI 1.40-3.25 than females (OR 1.56 95%CI 0.83-2.95, (SNP-gender interaction P = 0.048. We also identified a SNP-SNP interaction between T-cell activation related genes GATA3 and CD81 (interaction P = 0.0003. The fact that bladder cancer incidence is 3-4 times higher in males suggests the involvement of hormone levels. This biologic process-based analysis suggests candidate susceptibility markers and supports the theory that disrupted hormone regulation plays a role in bladder carcinogenesis.

  10. Genome-wide gene-gene interaction analysis for next-generation sequencing.

    Science.gov (United States)

    Zhao, Jinying; Zhu, Yun; Xiong, Momiao

    2016-03-01

    The critical barrier in interaction analysis for next-generation sequencing (NGS) data is that the traditional pairwise interaction analysis that is suitable for common variants is difficult to apply to rare variants because of their prohibitive computational time, large number of tests and low power. The great challenges for successful detection of interactions with NGS data are (1) the demands in the paradigm of changes in interaction analysis; (2) severe multiple testing; and (3) heavy computations. To meet these challenges, we shift the paradigm of interaction analysis between two SNPs to interaction analysis between two genomic regions. In other words, we take a gene as a unit of analysis and use functional data analysis techniques as dimensional reduction tools to develop a novel statistic to collectively test interaction between all possible pairs of SNPs within two genome regions. By intensive simulations, we demonstrate that the functional logistic regression for interaction analysis has the correct type 1 error rates and higher power to detect interaction than the currently used methods. The proposed method was applied to a coronary artery disease dataset from the Wellcome Trust Case Control Consortium (WTCCC) study and the Framingham Heart Study (FHS) dataset, and the early-onset myocardial infarction (EOMI) exome sequence datasets with European origin from the NHLBI's Exome Sequencing Project. We discovered that 6 of 27 pairs of significantly interacted genes in the FHS were replicated in the independent WTCCC study and 24 pairs of significantly interacted genes after applying Bonferroni correction in the EOMI study.

  11. Biology-Driven Gene-Gene Interaction Analysis of Age-Related Cataract in the eMERGE Network

    Science.gov (United States)

    Hall, Molly A; Verma, Shefali S; Wallace, John; Lucas, Anastasia; Berg, Richard L; Connolly, John; Crawford, Dana C; Crosslin, David R; de Andrade, Mariza; Doheny, Kimberly F; Haines, Jonathan L; Harley, John B; Jarvik, Gail P; Kitchner, Terrie; Kuivaniemi, Helena; Larson, Eric B; Carrell, David S; Tromp, Gerard; Vrabec, Tamara R; Pendergrass, Sarah A; McCarty, Catherine A; Ritchie, Marylyn D

    2015-01-01

    Bioinformatics approaches to examine gene-gene models provide a means to discover interactions between multiple genes that underlie complex disease. Extensive computational demands and adjusting for multiple testing make uncovering genetic interactions a challenge. Here, we address these issues using our knowledge-driven filtering method, Biofilter, to identify putative single nucleotide polymorphism (SNP) interaction models for cataract susceptibility, thereby reducing the number of models for analysis. Models were evaluated in 3,377 European Americans (1,185 controls, 2,192 cases) from the Marshfield Clinic, a study site of the Electronic Medical Records and Genomics (eMERGE) Network, using logistic regression. All statistically significant models from the Marshfield Clinic were then evaluated in an independent dataset of 4,311 individuals (742 controls, 3,569 cases), using independent samples from additional study sites in the eMERGE Network: Mayo Clinic, Group Health/University of Washington, Vanderbilt University Medical Center, and Geisinger Health System. Eighty-three SNP-SNP models replicated in the independent dataset at likelihood ratio test P < 0.05. Among the most significant replicating models was rs12597188 (intron of CDH1)–rs11564445 (intron of CTNNB1). These genes are known to be involved in processes that include: cell-to-cell adhesion signaling, cell-cell junction organization, and cell-cell communication. Further Biofilter analysis of all replicating models revealed a number of common functions among the genes harboring the 83 replicating SNP-SNP models, which included signal transduction and PI3K-Akt signaling pathway. These findings demonstrate the utility of Biofilter as a biology-driven method, applicable for any genome-wide association study dataset. PMID:25982363

  12. Mining disease genes using integrated protein-protein interaction and gene-gene co-regulation information.

    Science.gov (United States)

    Li, Jin; Wang, Limei; Guo, Maozu; Zhang, Ruijie; Dai, Qiguo; Liu, Xiaoyan; Wang, Chunyu; Teng, Zhixia; Xuan, Ping; Zhang, Mingming

    2015-01-01

    In humans, despite the rapid increase in disease-associated gene discovery, a large proportion of disease-associated genes are still unknown. Many network-based approaches have been used to prioritize disease genes. Many networks, such as the protein-protein interaction (PPI), KEGG, and gene co-expression networks, have been used. Expression quantitative trait loci (eQTLs) have been successfully applied for the determination of genes associated with several diseases. In this study, we constructed an eQTL-based gene-gene co-regulation network (GGCRN) and used it to mine for disease genes. We adopted the random walk with restart (RWR) algorithm to mine for genes associated with Alzheimer disease. Compared to the Human Protein Reference Database (HPRD) PPI network alone, the integrated HPRD PPI and GGCRN networks provided faster convergence and revealed new disease-related genes. Therefore, using the RWR algorithm for integrated PPI and GGCRN is an effective method for disease-associated gene mining.

  13. Using Linkage Analysis to Detect Gene-Gene Interactions. 2. Improved Reliability and Extension to More-Complex Models.

    Directory of Open Access Journals (Sweden)

    Susan E Hodge

    Full Text Available Detecting gene-gene interaction in complex diseases has become an important priority for common disease genetics, but most current approaches to detecting interaction start with disease-marker associations. These approaches are based on population allele frequency correlations, not genetic inheritance, and therefore cannot exploit the rich information about inheritance contained within families. They are also hampered by issues of rigorous phenotype definition, multiple test correction, and allelic and locus heterogeneity. We recently developed, tested, and published a powerful gene-gene interaction detection strategy based on conditioning family data on a known disease-causing allele or a disease-associated marker allele4. We successfully applied the method to disease data and used computer simulation to exhaustively test the method for some epistatic models. We knew that the statistic we developed to indicate interaction was less reliable when applied to more-complex interaction models. Here, we improve the statistic and expand the testing procedure. We computer-simulated multipoint linkage data for a disease caused by two interacting loci. We examined epistatic as well as additive models and compared them with heterogeneity models. In all our models, the at-risk genotypes are "major" in the sense that among affected individuals, a substantial proportion has a disease-related genotype. One of the loci (A has a known disease-related allele (as would have been determined from a previous analysis. We removed (pruned family members who did not carry this allele; the resultant dataset is referred to as "stratified." This elimination step has the effect of raising the "penetrance" and detectability at the second locus (B. We used the lod scores for the stratified and unstratified data sets to calculate a statistic that either indicated the presence of interaction or indicated that no interaction was detectable. We show that the new method is robust

  14. Gene-Gene Interactions in Renin-Angiotensin-Aldosterone System Contributes to End-Stage Renal Disease Susceptibility in a Han Chinese Population

    Directory of Open Access Journals (Sweden)

    Sui-Lung Su

    2014-01-01

    Full Text Available Objective. In this study, we investigated whether RAAS gene single nucleotide polymorphisms (SNPs and their interactions were associated with end-stage renal stage (ESRD. Methodology and Results. This was a case-control study for 647 ESRD cases and 644 controls. AGT (M235T (rs699 and T174M (rs4762, AGTR1 (A1166C (rs5186 and C573T (rs5182, ACE (I/D (rs1799752 and G2350A (rs4343, and CYP11B2 C-344T (rs1799998 were genotyped and compared between cases and controls to identify SNPs associated with ESRD susceptibility. Multifactor dimensionality reduction (MDR was used to identify gene-gene interactions. Several RAAS genes were associated with ESRD: AGT M235T, ACE I/D, ACE G2350A, and CYP11B2 C-344T. By MDR analysis, a three-locus model (ACE ID/ACE G2350A/CYP11B2 C-344T of gene-gene interaction was the best for predicting ESRD risk, and its maximum testing accuracy was 56.08% and maximum cross-validation consistency was 9/10. ESRD risk was higher with the simultaneous occurrence of ACE I/D DD-ACE G2350A AA. AGT, ACE, and CYP11B2 gene polymorphisms are associated with ESRD. Conclusions. The gene-gene interaction effects of ACE I/D, ACE G2350A, and CYP11B2 C-344T polymorphisms are more important than individual factors for ESRD development among Han Chinese.

  15. Gene-gene interactions of fatty acid synthase (FASN) using multifactor-dimensionality reduction method in Korean cattle.

    Science.gov (United States)

    Lee, Jeayoung; Jin, Mehyun; Lee, Yoonseok; Ha, Jaejung; Yeo, Jungsou; Oh, Dongyep

    2014-01-01

    We examined the gene-gene interactions of five exonic single nucleotide polymorphisms (SNPs) in the gene encoding fatty acid synthase using 513 Korean cattle and using the model free and the non-parametrical multifactor dimensionality reduction method for the analysis. The five SNPs of g.12870 T>C, g.13126 T>C, g.15532 C>A, g.16907 T>C and g.17924 G>A associated with a variety of fatty acid compositions and marbling score were used in this study. The two-factor interaction between g.13126 T>C and g.15532 C>A had the highest training-balanced among the five-factor models and a testing-balanced accuracy at 70.18 % on C18:1 with a cross-validation consistency of 10 out of 10. Also, the two-factor interaction between g.13126 T>C and g.15532 C>A had the highest testing-balanced accuracy at 68.59 % with a 10 out of 10 cross-validation consistency, than any other models on MUFA. In MS, a single SNP g.15532 C>A had the best accuracy at 58.85 % and the two-factor interaction model g.12870 T>C and g.15532 C>A had the highest testing-balanced accuracy at 64.00 %. The three-factor interaction model g.12870 T>C, g.13126 T>C and g.15532 C>A was recorded as having a high testing-balanced accuracy of 63.24 %, but it was lower than the two-factor interaction model. We used likelihood ratio tests for interaction, and Chi square tests to validate our results, with all tests showing statistical significance. We also compared this with mean scores between the high-risk trait group and low-risk trait group. The genotypes of TTCA, TTAA and TCAA at g.15532 and g.13126 on C18:1, genotypes TTCC, TTCA, TTAA, TCAA CCAA at g.15532 and g.13126 on MUFA and genotypes CCCC, TCCA, CCCA, TTAA, TCAA and CCAA at g.15532 and g.12870 on MS were recommended for the genetic improvement of beef quality.

  16. Association of peroxisome proliferator-activated receptor single-nucleotide polymorphisms and gene-gene interactions with the lipoprotein(a)

    Institute of Scientific and Technical Information of China (English)

    解惠坚

    2014-01-01

    Objective To examine the associations of 10 singlenucleotide polymorphisms(SNPs)in peroxisome proliferator-activated receptor(PPARs)gene with lipoprotein(a)level,and to investigate if there is gene-gene interaction among the SNPs on lipoprotein(a)level.Methods Totally 644 subjects(234 men and 410 women)were enrolled from Prevention of Multiple Metabolic Disorders and Metabolic Syndrome Study Cohort,which was an urban community survey study conducted in Jiangsu province.Ten SNPs in PPARα(rs135539,rs4253778,

  17. CYP1A1, GCLC, AGT, AGTR1 gene-gene interactions in community-acquired pneumonia pulmonary complications.

    Science.gov (United States)

    Salnikova, Lyubov E; Smelaya, Tamara V; Golubev, Arkadiy M; Rubanovich, Alexander V; Moroz, Viktor V

    2013-11-01

    This study was conducted to establish the possible contribution of functional gene polymorphisms in detoxification/oxidative stress and vascular remodeling pathways to community-acquired pneumonia (CAP) susceptibility in the case-control study (350 CAP patients, 432 control subjects) and to predisposition to the development of CAP complications in the prospective study. All subjects were genotyped for 16 polymorphic variants in the 14 genes of xenobiotics detoxification CYP1A1, AhR, GSTM1, GSTT1, ABCB1, redox-status SOD2, CAT, GCLC, and vascular homeostasis ACE, AGT, AGTR1, NOS3, MTHFR, VEGFα. Risk of pulmonary complications (PC) in the single locus analysis was associated with CYP1A1, GCLC and AGTR1 genes. Extra PC (toxic shock syndrome and myocarditis) were not associated with these genes. We evaluated gene-gene interactions using multi-factor dimensionality reduction, and cumulative gene risk score approaches. The final model which included >5 risk alleles in the CYP1A1 (rs2606345, rs4646903, rs1048943), GCLC, AGT, and AGTR1 genes was associated with pleuritis, empyema, acute respiratory distress syndrome, all PC and acute respiratory failure (ARF). We considered CYP1A1, GCLC, AGT, AGTR1 gene set using Set Distiller mode implemented in GeneDecks for discovering gene-set relations via the degree of sharing descriptors within a given gene set. N-acetylcysteine and oxygen were defined by Set Distiller as the best descriptors for the gene set associated in the present study with PC and ARF. Results of the study are in line with literature data and suggest that genetically determined oxidative stress exacerbation may contribute to the progression of lung inflammation.

  18. Differences in Gene-Gene Interactions in Graves' Disease Patients Stratified by Age of Onset.

    Directory of Open Access Journals (Sweden)

    Beata Jurecka-Lubieniecka

    Full Text Available Graves' disease (GD is a complex disease in which genetic predisposition is modified by environmental factors. Each gene exerts limited effects on the development of autoimmune disease (OR = 1.2-1.5. An epidemiological study revealed that nearly 70% of the risk of developing inherited autoimmunological thyroid diseases (AITD is the result of gene interactions. In the present study, we analyzed the effects of the interactions of multiple loci on the genetic predisposition to GD. The aim of our analyses was to identify pairs of genes that exhibit a multiplicative interaction effect.A total of 709 patients with GD were included in the study. The patients were stratified into more homogeneous groups depending on the age at time of GD onset: younger patients less than 30 years of age and older patients greater than 30 years of age. Association analyses were performed for genes that influence the development of GD: HLADRB1, PTPN22, CTLA4 and TSHR. The interactions among polymorphisms were analyzed using the multiple logistic regression and multifactor dimensionality reduction (MDR methods.GD patients stratified by the age of onset differed in the allele frequencies of the HLADRB1*03 and 1858T polymorphisms of the PTPN22 gene (OR = 1.7, p = 0.003; OR = 1.49, p = 0.01, respectively. We evaluated the genetic interactions of four SNPs in a pairwise fashion with regard to disease risk. The coexistence of HLADRB1 with CTLA4 or HLADRB1 with PTPN22 exhibited interactions on more than additive levels (OR = 3.64, p = 0.002; OR = 4.20, p < 0.001, respectively. These results suggest that interactions between these pairs of genes contribute to the development of GD. MDR analysis confirmed these interactions.In contrast to a single gene effect, we observed that interactions between the HLADRB1/PTPN22 and HLADRB1/CTLA4 genes more closely predicted the risk of GD onset in young patients.

  19. Exploring Plant Co-Expression and Gene-Gene Interactions with CORNET 3.0.

    Science.gov (United States)

    Van Bel, Michiel; Coppens, Frederik

    2017-01-01

    Selecting and filtering a reference expression and interaction dataset when studying specific pathways and regulatory interactions can be a very time-consuming and error-prone task. In order to reduce the duplicated efforts required to amass such datasets, we have created the CORNET (CORrelation NETworks) platform which allows for easy access to a wide variety of data types: coexpression data, protein-protein interactions, regulatory interactions, and functional annotations. The CORNET platform outputs its results in either text format or through the Cytoscape framework, which is automatically launched by the CORNET website.CORNET 3.0 is the third iteration of the web platform designed for the user exploration of the coexpression space of plant genomes, with a focus on the model species Arabidopsis thaliana. Here we describe the platform: the tools, data, and best practices when using the platform. We indicate how the platform can be used to infer networks from a set of input genes, such as upregulated genes from an expression experiment. By exploring the network, new target and regulator genes can be discovered, allowing for follow-up experiments and more in-depth study. We also indicate how to avoid common pitfalls when evaluating the networks and how to avoid over interpretation of the results.All CORNET versions are available at http://bioinformatics.psb.ugent.be/cornet/ .

  20. Dopamine transporter DAT and receptor DRD2 variants affect risk of lethal cocaine abuse: a gene-gene-environment interaction.

    Science.gov (United States)

    Sullivan, D; Pinsonneault, J K; Papp, A C; Zhu, H; Lemeshow, S; Mash, D C; Sadee, W

    2013-01-22

    Epistatic gene-gene interactions could contribute to the heritability of complex multigenic disorders, but few examples have been reported. Here, we focus on the role of aberrant dopaminergic signaling, involving the dopamine transporter DAT, a cocaine target, and the dopamine D2 receptor, which physically interacts with DAT. Splicing polymorphism rs2283265 of DRD2, encoding D2 receptors, were shown to confer risk of cocaine overdose/death (odds ratio ∼3) in subjects and controls from the Miami Dade County Brain Bank.(1) Risk of cocaine-related death attributable to the minor allele of rs2283265 was significantly enhanced to OR=7.5 (P=0.0008) in homozygous carriers of the main 6-repeat allele of DAT rs3836790, a regulatory VNTR in intron8 lacking significant effect itself. In contrast, carriers of the minor 5-repeat DAT allele showed no significant risk (OR=1.1, P=0.84). DAT rs3836790 and DRD2 rs2283265 also interacted by modulating DAT protein activity in the ventral putamen of cocaine abusers. In high-linkage disequilibrium with the VNTR, DAT rs6347 in exon9 yielded similar results. Assessing the impact of DAT alone, a rare DAT haplotype formed by the minor alleles of rs3836790 and rs27072, a regulatory DAT variant in the 3'-UTR, occurred in nearly one-third of the cocaine abusers but was absent in African American controls, apparently conferring strong risk. These results demonstrate gene-gene-drug interaction affecting risk of fatal cocaine intoxication.

  1. Gene-Gene Interactions Among PRKCA, NOS3 and BDKRB2 Polymorphisms Affect the Antihypertensive Effects of Enalapril.

    Science.gov (United States)

    Oliveira-Paula, Gustavo H; Luizon, Marcelo R; Lacchini, Riccardo; Fontana, Vanessa; Silva, Pamela S; Biagi, Celso; Tanus-Santos, Jose E

    2017-03-01

    Protein kinase C (PKC) signalling is critically involved in the control of blood pressure. Angiotensin-converting enzyme inhibitors (ACEi) affect PKC expression and activity, which are partially associated with the responses to ACEi. We examined whether PRKCA (protein kinase C, alpha) polymorphisms (rs887797 C>T, rs1010544 T>C and rs16960228 G>A), or haplotypes, and gene-gene interactions within the ACEi pathway affect the antihypertensive responses in 104 hypertensive patients treated with enalapril as monotherapy. Patients were classified as poor responders (PR) or good responders (GR) to enalapril if their changes in mean arterial pressure were lower or higher than the median value, respectively. Multi-factor dimensionality reduction was used to characterize interactions among PRKCA, NOS3 (nitric oxide synthase 3) and BDKRB2 (bradykinin receptor B2) polymorphisms. The TC+CC genotypes for the rs1010544 polymorphism were more frequent in GR than in PR (p = 0.037). Conversely, the GA+AA genotypes for the rs16960228 polymorphism, and the CTA haplotype, were more frequent in PR than in GR (p = 0.040 and p = 0.008, respectively). Moreover, the GG genotype for the PRKCA rs16960228 polymorphism was associated with PR or GR depending on the genotypes for the rs2070744 (NOS3) and rs1799722 (BDKRB2) polymorphisms (p = 0.012). Our results suggest that PRKCA polymorphisms and gene-gene interactions within the ACEi pathway affect the antihypertensive responses to enalapril. © 2016 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

  2. Dominance from the perspective of gene-gene and gene-chemical interactions.

    Science.gov (United States)

    Gladki, Arkadiusz; Zielenkiewicz, Piotr; Kaczanowski, Szymon

    2016-02-01

    In this study, we used genetic interaction (GI) and gene-chemical interaction (GCI) data to compare mutations with different dominance phenotypes. Our analysis focused primarily on Saccharomyces cerevisiae, where haploinsufficient genes (HI; genes with dominant loss-of-function mutations) were found to be participating in gene expression processes, namely, the translation and regulation of gene transcription. Non-ribosomal HI genes (mainly regulators of gene transcription) were found to have more GIs and GCIs than haplosufficient (HS) genes. Several properties seem to lead to the enrichment of interactions, most notably, the following: importance, pleiotropy, gene expression level and gene expression variation. Importantly, after these properties were appropriately considered in the analysis, the correlation between dominance and GI/GCI degrees was still observed. Strikingly, for the GCIs of heterozygous strains, haploinsufficiency was the only property significantly correlated with the number of GCIs. We found ribosomal HI genes to be depleted in GIs/GCIs. This finding can be explained by their high variation in gene expression under different genetic backgrounds and environmental conditions. We observed the same distributions of GIs among non-ribosomal HI, ribosomal HI and HS genes in three other species: Schizosaccharomyces pombe, Drosophila melanogaster and Homo sapiens. One potentially interesting exception was the lack of significant differences in the degree of GIs between non-ribosomal HI and HS genes in Schizosaccharomyces pombe.

  3. Gene-gene and gene-environment interactions in prostate, breast and colorectal cancer

    DEFF Research Database (Denmark)

    Kopp, Tine Iskov

    transporters and IL-10 in relation to CRC. Paper V illustrated that genetic variations in CYP19A1 predicts circulating sex-hormone levels in postmenopausal women, and that alcohol intake affects female sex-hormone concentrations in the blood. However, it was not possible to put PPARγ and the aromatase...... single-gene mutations due to their low frequency in the general population. Overall, the contribution from hereditary factors to the causation of BC is only 27%, whereas genetics contributes to 35% and 42% for CRC and PC, respectively. Additionally, immigrations studies point to environmental factors......, such as alcohol consumption, smoking, obesity, inflammation and high meat intake; whereas other factors protect against cancer, such as high intake of dietary fibre, fruits and vegetables, and physical activity. Investigating the interactions between genetic variations and environmental factors, such as dietary...

  4. Gene-gene interaction and functional impact of polymorphisms on innate immune genes in controlling Plasmodium falciparum blood infection level.

    Directory of Open Access Journals (Sweden)

    Madhumita Basu

    Full Text Available Genetic variations in toll-like receptors and cytokine genes of the innate immune pathways have been implicated in controlling parasite growth and the pathogenesis of Plasmodium falciparum mediated malaria. We previously published genetic association of TLR4 non-synonymous and TNF-α promoter polymorphisms with P.falciparum blood infection level and here we extend the study considerably by (i investigating genetic dependence of parasite-load on interleukin-12B polymorphisms, (ii reconstructing gene-gene interactions among candidate TLRs and cytokine loci, (iii exploring genetic and functional impact of epistatic models and (iv providing mechanistic insights into functionality of disease-associated regulatory polymorphisms. Our data revealed that carriage of AA (P = 0.0001 and AC (P = 0.01 genotypes of IL12B 3'UTR polymorphism was associated with a significant increase of mean log-parasitemia relative to rare homozygous genotype CC. Presence of IL12B+1188 polymorphism in five of six multifactor models reinforced its strong genetic impact on malaria phenotype. Elevation of genetic risk in two-component models compared to the corresponding single locus and reduction of IL12B (2.2 fold and lymphotoxin-α (1.7 fold expressions in patients'peripheral-blood-mononuclear-cells under TLR4Thr399Ile risk genotype background substantiated the role of Multifactor Dimensionality Reduction derived models. Marked reduction of promoter activity of TNF-α risk haplotype (C-C-G-G compared to wild-type haplotype (T-C-G-G with (84% and without (78% LPS stimulation and the loss of binding of transcription factors detected in-silico supported a causal role of TNF-1031. Significantly lower expression of IL12B+1188 AA (5 fold and AC (9 fold genotypes compared to CC and under-representation (P = 0.0048 of allele A in transcripts of patients' PBMCs suggested an Allele-Expression-Imbalance. Allele (A+1188C dependent differential stability (2 fold of IL12B-transcripts upon

  5. Gene-gene interaction and RNA splicing profiles of MAP2K4 gene in rheumatoid arthritis.

    Science.gov (United States)

    Shchetynsky, Klementy; Protsyuk, Darya; Ronninger, Marcus; Diaz-Gallo, Lina-Marcela; Klareskog, Lars; Padyukov, Leonid

    2015-05-01

    We performed gene-gene interaction analysis, with HLA-DRB1 shared epitope (SE) alleles for 195 SNPs within immunologically important MAP2K, MAP3K and MAP4K gene families, in 2010 rheumatoid arthritis (RA) patients and 2280 healthy controls. We found a significant statistical interaction for rs10468473 with SE alleles in autoantibody-positive RA. Individuals heterozygous for rs10468473 demonstrated higher expression of total MAP2K4 mRNA in blood, compared to A-allele homozygous. We discovered a novel, putatively translated, "cassette exon" RNA splice form of MAP2K4, differentially expressed in peripheral blood mononuclear cells from 88 RA cases and controls. Within the group of RA patients, we observed a correlation of MAP2K4 isoform expression with carried SE alleles, autoantibody, and rheumatoid factor profiles. TNF-dependent modulation of isoform expression pattern was detected in the Jurkat cell line. Our data suggest a genetic interaction between MAP2K4 and HLA-DRB1, and the importance of rs10468473 and MAP2K4 splice variants in the development of autoantibody-positive RA.

  6. NEXT-GENERATION ANALYSIS OF CATARACTS: DETERMINING KNOWLEDGE DRIVEN GENE-GENE INTERACTIONS USING BIOFILTER, AND GENE-ENVIRONMENT INTERACTIONS USING THE PHENX TOOLKIT*

    Science.gov (United States)

    Pendergrass, Sarah A.; Verma, Shefali S.; Holzinger, Emily R.; Moore, Carrie B.; Wallace, John; Dudek, Scott M.; Huggins, Wayne; Kitchner, Terrie; Waudby, Carol; Berg, Richard; McCarty, Catherine A.; Ritchie, Marylyn D.

    2013-01-01

    Investigating the association between biobank derived genomic data and the information of linked electronic health records (EHRs) is an emerging area of research for dissecting the architecture of complex human traits, where cases and controls for study are defined through the use of electronic phenotyping algorithms deployed in large EHR systems. For our study, 2580 cataract cases and 1367 controls were identified within the Marshfield Personalized Medicine Research Project (PMRP) Biobank and linked EHR, which is a member of the NHGRI-funded electronic Medical Records and Genomics (eMERGE) Network. Our goal was to explore potential gene-gene and gene-environment interactions within these data for 529,431 single nucleotide polymorphisms (SNPs) with minor allele frequency > 1%, in order to explore higher level associations with cataract risk beyond investigations of single SNP-phenotype associations. To build our SNP-SNP interaction models we utilized a prior-knowledge driven filtering method called Biofilter to minimize the multiple testing burden of exploring the vast array of interaction models possible from our extensive number of SNPs. Using the Biofilter, we developed 57,376 prior-knowledge directed SNP-SNP models to test for association with cataract status. We selected models that required 6 sources of external domain knowledge. We identified 5 statistically significant models with an interaction term with p-value < 0.05, as well as an overall model with p-value < 0.05 associated with cataract status. We also conducted gene-environment interaction analyses for all GWAS SNPs and a set of environmental factors from the PhenX Toolkit: smoking, UV exposure, and alcohol use; these environmental factors have been previously associated with the formation of cataracts. We found a total of 288 models that exhibit an interaction term with a p-value ≤ 1×10−4 associated with cataract status. Our results show these approaches enable advanced searches for epistasis

  7. Genetic Association and Gene-gene interaction of HAS2, HABP1 and HYAL3 Implicate Hyaluronan Metabolic Genes in Glaucomatous Neurodegeneration

    Directory of Open Access Journals (Sweden)

    Kaustuv Basu

    2012-01-01

    Full Text Available Hyaluronan (HA plays a significant role in maintaining aqueous humor outflow in trabecular meshwork, the primary ocular tissue involved in glaucoma. We examined potential association of the single nucleotide polymorphisms (SNPs of the HA synthesizing gene – hyaluronan synthase 2 (HAS2, hyaluronan binding protein 1 (HABP1 and HA catabolic gene hyaluronidase 3 (HYAL3 in the primary open angle glaucoma (POAG patients in the Indian population. Thirteen tagged SNPs (6 for HAS2, 3 for HABP1 and 4 for HYAL3 were genotyped in 116 high tension (HTG, 321 non-high tension glaucoma (NHTG samples and 96 unrelated, age-matched, glaucoma-negative, control samples. Allelic and genotypic association were analyzed by PLINK v1.04; haplotypes were identified using PHASE v2.1 and gene-gene interaction was analyzed using multifactor dimensionality reduction (MDR v2.0. An allelic association (rs6651224; p = 0.03; OR: 0.49; 95% CI: 0.25–0.94 was observed at the second intron (C>G of HAS2 both for NHTG and HTG. rs1057308 revealed a genotypic association (p = 0.03 at the 5’ UTR of HAS2 with only HTG. TCT haplotype (rs1805429 – rs2472614 – rs8072363 in HABP1 and TTAG and TTGA (rs2285044 – rs3774753 – rs1310073 – rs1076872 in HYAL3 were found to be significantly high (p < 0.05 both for HTG and NHTG compared to controls. Gene-gene interaction revealed HABP1 predominantly interacts with HAS2 in HTG while it associates with both HYAL3 and HAS2 in NHTG. This is the first genetic evidence, albeit from a smaller study, that the natural polymorphisms in the genes involved in hyaluronan metabolism are potentially involved in glaucomatous neurodegeneration.

  8. Evidence of gene-gene interaction and age-at-diagnosis effects in type 1 diabetes

    DEFF Research Database (Denmark)

    Howson, Joanna M M; Cooper, Jason D; Smyth, Deborah J

    2012-01-01

    diabetes samples (6,750 British diabetic individuals and 8,116 affected family samples of European descent) were genotyped at 38 confirmed type 1 diabetes-associated non-HLA regions and used to test for interaction of association with age-at-diagnosis, sex, and HLA class II genotypes using regression...... of the familial clustering of the disease....

  9. MDM2 SNP309, gene-gene interaction, and tumor susceptibility: an updated meta-analysis

    Directory of Open Access Journals (Sweden)

    Wu Wei

    2011-05-01

    Full Text Available Abstract Background The tumor suppressor gene p53 is involved in multiple cellular pathways including apoptosis, transcriptional control, and cell cycle regulation. In the last decade it has been demonstrated that the single nucleotide polymorphism (SNP at codon 72 of the p53 gene is associated with the risk for development of various neoplasms. MDM2 SNP309 is a single nucleotide T to G polymorphism located in the MDM2 gene promoter. From the time that this well-characterized functional polymorphism was identified, a variety of case-control studies have been published that investigate the possible association between MDM2 SNP309 and cancer risk. However, the results of the published studies, as well as the subsequent meta-analyses, remain contradictory. Methods To investigate whether currently published epidemiological studies can clarify the potential interaction between MDM2 SNP309 and the functional genetic variant in p53 codon72 (Arg72Pro and p53 mutation status, we performed a meta-analysis of the risk estimate on 27,813 cases with various tumor types and 30,295 controls. Results The data we reviewed indicated that variant homozygote 309GG and heterozygote 309TG were associated with a significant increased risk of all tumor types (homozygote comparison: odds ratio (OR = 1.25, 95% confidence interval (CI = 1.13-1.37; heterozygote comparison: OR = 1.10, 95% CI = 1.03-1.17. We also found that the combination of GG and Pro/Pro, TG and Pro/Pro, GG and Arg/Arg significantly increased the risk of cancer (OR = 3.38, 95% CI = 1.77-6.47; OR = 1.88, 95% CI = 1.26-2.81; OR = 1.96, 95% CI = 1.01-3.78, respectively. In a stratified analysis by tumor location, we also found a significant increased risk in brain, liver, stomach and uterus cancer (OR = 1.47, 95% CI = 1.06-2.03; OR = 2.24, 95%CI = 1.57-3.18; OR = 1.54, 95%CI = 1.04-2.29; OR = 1.34, 95%CI = 1.07-1.29, respectively. However, no association was seen between MDM2 SNP309 and tumor susceptibility

  10. Knowledge-driven multi-locus analysis reveals gene-gene interactions influencing HDL cholesterol level in two independent EMR-linked biobanks.

    Science.gov (United States)

    Turner, Stephen D; Berg, Richard L; Linneman, James G; Peissig, Peggy L; Crawford, Dana C; Denny, Joshua C; Roden, Dan M; McCarty, Catherine A; Ritchie, Marylyn D; Wilke, Russell A

    2011-05-11

    Genome-wide association studies (GWAS) are routinely being used to examine the genetic contribution to complex human traits, such as high-density lipoprotein cholesterol (HDL-C). Although HDL-C levels are highly heritable (h(2)∼0.7), the genetic determinants identified through GWAS contribute to a small fraction of the variance in this trait. Reasons for this discrepancy may include rare variants, structural variants, gene-environment (GxE) interactions, and gene-gene (GxG) interactions. Clinical practice-based biobanks now allow investigators to address these challenges by conducting GWAS in the context of comprehensive electronic medical records (EMRs). Here we apply an EMR-based phenotyping approach, within the context of routine care, to replicate several known associations between HDL-C and previously characterized genetic variants: CETP (rs3764261, p = 1.22e-25), LIPC (rs11855284, p = 3.92e-14), LPL (rs12678919, p = 1.99e-7), and the APOA1/C3/A4/A5 locus (rs964184, p = 1.06e-5), all adjusted for age, gender, body mass index (BMI), and smoking status. By using a novel approach which censors data based on relevant co-morbidities and lipid modifying medications to construct a more rigorous HDL-C phenotype, we identified an association between HDL-C and TRIB1, a gene which previously resisted identification in studies with larger sample sizes. Through the application of additional analytical strategies incorporating biological knowledge, we further identified 11 significant GxG interaction models in our discovery cohort, 8 of which show evidence of replication in a second biobank cohort. The strongest predictive model included a pairwise interaction between LPL (which modulates the incorporation of triglyceride into HDL) and ABCA1 (which modulates the incorporation of free cholesterol into HDL). These results demonstrate that gene-gene interactions modulate complex human traits, including HDL cholesterol.

  11. Gene-gene interactions of the INSIG1 and INSIG2 in metabolic syndrome in schizophrenic patients treated with atypical antipsychotics.

    Science.gov (United States)

    Liou, Y-J; Bai, Y M; Lin, E; Chen, J-Y; Chen, T-T; Hong, C-J; Tsai, S-J

    2012-02-01

    The use of atypical antipsychotics (AAPs) is associated with increasing the risk of the metabolic syndrome (MetS), which is an important risk factor for cardiovascular disease and diabetes. Two insulin-induced gene (INSIG) isoforms, designated INSIG-1 and INSIG-2 encode two proteins that mediate feedback control of lipid metabolism. In this genetic case-control study, we investigated whether the common variants in INSIG1 and INSIG2 genes were associated with MetS in schizophrenic patients treated with atypical antipsychctics. The study included 456 schizophrenia patients treated with clozapine (n=171), olanzapine (n=91) and risperidone (n=194), for an average of 45.5±27.6 months. The prevalence of MetS among all subjects was 22.8% (104/456). Two single-nucleotide polymorphisms (SNPs) of the INSIG1 gene and seven SNPs of the INSIG2 gene were chosen as haplotype-tagging SNPs. In single-marker-based analysis, the INSIG2 rs11123469-C homozygous genotype was found to be more frequent in the patients with MetS than those without MetS (P=0.001). In addition, haplotype analysis showed that the C-C-C haplotype of rs11123469-rs10185316- rs1559509 of the INSIG2 gene significantly increased the risk of MetS (P=0.0023). No significant associations were found between polymorphisms of INSIG1 gene and MetS, however, INSIG1 and INSIG2 interactions were found in the significant 3-locus and 4-locus gene-gene interaction models (P=0.003 and 0.012, respectively). The results suggest that the INSIG2 gene may be associated with MetS in patients treated with AAPs independently or in an interactive manner with INSIG1.

  12. CARAT-GxG: CUDA-Accelerated Regression Analysis Toolkit for Large-Scale Gene-Gene Interaction with GPU Computing System.

    Science.gov (United States)

    Lee, Sungyoung; Kwon, Min-Seok; Park, Taesung

    2014-01-01

    In genome-wide association studies (GWAS), regression analysis has been most commonly used to establish an association between a phenotype and genetic variants, such as single nucleotide polymorphism (SNP). However, most applications of regression analysis have been restricted to the investigation of single marker because of the large computational burden. Thus, there have been limited applications of regression analysis to multiple SNPs, including gene-gene interaction (GGI) in large-scale GWAS data. In order to overcome this limitation, we propose CARAT-GxG, a GPU computing system-oriented toolkit, for performing regression analysis with GGI using CUDA (compute unified device architecture). Compared to other methods, CARAT-GxG achieved almost 700-fold execution speed and delivered highly reliable results through our GPU-specific optimization techniques. In addition, it was possible to achieve almost-linear speed acceleration with the application of a GPU computing system, which is implemented by the TORQUE Resource Manager. We expect that CARAT-GxG will enable large-scale regression analysis with GGI for GWAS data.

  13. Glutathione S-transferase P1, gene-gene interaction, and lung cancer susceptibility in the Chinese population: An updated meta-analysis and review

    Directory of Open Access Journals (Sweden)

    Xue-Ming Li

    2015-01-01

    Full Text Available Aim of Study: To assess the impact of glutathione S-transferase P1 (GSTP1 Ile105Val polymorphism on the risk of lung cancer in the Chinese population, an updated meta-analysis and review was performed. Materials and Methods: Relevant studies were identified from PubMed, Springer Link, Ovid, Chinese Wanfang Data Knowledge Service Platform, Chinese National Knowledge Infrastructure, and Chinese Biology Medicine published through January 22, 2015. The odds ratios (ORs and 95% confidence intervals (CIs were calculated to estimate the strength of the associations. Results: A total of 13 case-control studies, including 2026 lung cancer cases and 2451 controls, were included in this meta-analysis. Overall, significantly increased lung cancer risk was associated with the variant genotypes of GSTP1 polymorphism in the Chinese population (GG vs. AA: OR = 1.36, 95% CI = 1.01-1.84. In subgroup analyses stratified by geographic area and source of controls, the significant results were found in population-based studies (GG vs. AA: OR = 1.62, 95% CI: 1.13-2.31; GG vs. AG: OR = 1.49, 95% CI: 1.03-2.16; GG vs. AA + AG: OR = 1.55, 95% CI: 1.12-2.26. A gene-gene interaction analysis showed that there was an interaction for individuals with combination of GSTM1 (or GSTT1 null genotype and GSTP1 (AG + GG mutant genotype for lung cancer risk in Chinese. Conclusion: This meta-analysis suggests that GSTP1 Ile105Val polymorphism may increase the risk of lung cancer in the Chinese population.

  14. Using linkage analysis to detect gene-gene interaction by stratifying family data on known disease, or disease-associated, alleles.

    Directory of Open Access Journals (Sweden)

    Barbara Corso

    Full Text Available Detecting gene-gene interaction in complex diseases is a major challenge for common disease genetics. Most interaction detection approaches use disease-marker associations and such methods have low power and unknown reliability in real data. We developed and tested a powerful linkage-analysis-based gene-gene interaction detection strategy based on conditioning the family data on a known disease-causing allele or disease-associated marker allele. We computer-generated multipoint linkage data for a disease caused by two epistatically interacting loci (A and B. We examined several two-locus epistatic inheritance models: dominant-dominant, dominant-recessive, recessive-dominant, recessive-recessive. At one of the loci (A, there was a known disease-related allele. We stratified the family data on the presence of this allele, eliminating family members who were without it. This elimination step has the effect of raising the "penetrance" at the second locus (B. We then calculated the lod score at the second locus (B and compared the pre- and post-stratification lod scores at B. A positive difference indicated interaction. We also examined if it was possible to detect interaction with locus B based on a disease-marker association (instead of an identified disease allele at locus A. We also tested whether the presence of genetic heterogeneity would generate false positive evidence of interaction. The power to detect interaction for a known disease allele was 60-90%. The probability of false positives, based on heterogeneity, was low. Decreasing linkage disequilibrium between the disease and marker at locus A decreased the likelihood of detecting interaction. The allele frequency of the associated marker made little difference to the power.

  15. A systematic gene-gene and gene-environment interaction analysis of DNA repair genes XRCC1, XRCC2, XRCC3, XRCC4, and oral cancer risk.

    Science.gov (United States)

    Yang, Cheng-Hong; Lin, Yu-Da; Yen, Ching-Yui; Chuang, Li-Yeh; Chang, Hsueh-Wei

    2015-04-01

    Oral cancer is the sixth most common cancer worldwide with a high mortality rate. Biomarkers that anticipate susceptibility, prognosis, or response to treatments are much needed. Oral cancer is a polygenic disease involving complex interactions among genetic and environmental factors, which require multifaceted analyses. Here, we examined in a dataset of 103 oral cancer cases and 98 controls from Taiwan the association between oral cancer risk and the DNA repair genes X-ray repair cross-complementing group (XRCCs) 1-4, and the environmental factors of smoking, alcohol drinking, and betel quid (BQ) chewing. We employed logistic regression, multifactor dimensionality reduction (MDR), and hierarchical interaction graphs for analyzing gene-gene (G×G) and gene-environment (G×E) interactions. We identified a significantly elevated risk of the XRCC2 rs2040639 heterozygous variant among smokers [adjusted odds ratio (OR) 3.7, 95% confidence interval (CI)=1.1-12.1] and alcohol drinkers [adjusted OR=5.7, 95% CI=1.4-23.2]. The best two-factor based G×G interaction of oral cancer included the XRCC1 rs1799782 and XRCC2 rs2040639 [OR=3.13, 95% CI=1.66-6.13]. For the G×E interaction, the estimated OR of oral cancer for two (drinking-BQ chewing), three (XRCC1-XRCC2-BQ chewing), four (XRCC1-XRCC2-age-BQ chewing), and five factors (XRCC1-XRCC2-age-drinking-BQ chewing) were 32.9 [95% CI=14.1-76.9], 31.0 [95% CI=14.0-64.7], 49.8 [95% CI=21.0-117.7] and 82.9 [95% CI=31.0-221.5], respectively. Taken together, the genotypes of XRCC1 rs1799782 and XRCC2 rs2040639 DNA repair genes appear to be significantly associated with oral cancer. These were enhanced by exposure to certain environmental factors. The observations presented here warrant further research in larger study samples to examine their relevance for routine clinical care in oncology.

  16. Development of GMDR-GPU for gene-gene interaction analysis and its application to WTCCC GWAS data for type 2 diabetes.

    Directory of Open Access Journals (Sweden)

    Zhixiang Zhu

    Full Text Available Although genome-wide association studies (GWAS have identified a significant number of single-nucleotide polymorphisms (SNPs associated with many complex human traits, the susceptibility loci identified so far can explain only a small fraction of the genetic risk. Among other possible explanations, the lack of a comprehensive examination of gene-gene interaction (G×G is often considered a source of the missing heritability. Previously, we reported a model-free Generalized Multifactor Dimensionality Reduction (GMDR approach for detecting G×G in both dichotomous and quantitative phenotypes. However, the computational burden and less efficient implementation of the original programs make them impossible to use for GWAS. In this study, we developed a graphics processing unit (GPU-based GMDR program (named GWAS-GPU, which is able not only to analyze GWAS data but also to run much faster than the earlier version of the GMDR program. As a demonstration of the program, we used the GMDR-GPU software to analyze a publicly available GWAS dataset on type 2 diabetes (T2D from the Wellcome Trust Case Control Consortium. Through an exhaustive search of pair-wise interactions and a selected search of three- to five-way interactions conditioned on significant pair-wise results, we identified 24 core SNPs in six genes (FTO: rs9939973, rs9940128, rs9922047, rs1121980, rs9939609, rs9930506; TSPAN8: rs1495377; TCF7L2: rs4074720, rs7901695, rs4506565, rs4132670, rs10787472, rs11196205, rs10885409, rs11196208; L3MBTL3: rs10485400, rs4897366; CELF4: rs2852373, rs608489; RUNX1: rs445984, rs1040328, rs990074, rs2223046, rs2834970 that appear to be important for T2D. Of these core SNPs, 11 in FTO, TSPAN8, and TCF7L2 have been reported to be associated with T2D, obesity, or both, providing an independent replication of previously reported SNPs. Importantly, we identified three new susceptibility genes; i.e., L3MBTL3, CELF4, and RUNX1, for T2D, a finding that warrants

  17. Gene-gene interactions among genetic variants from obesity candidate genes for nonobese and obese populations in type 2 diabetes.

    Science.gov (United States)

    Lin, Eugene; Pei, Dee; Huang, Yi-Jen; Hsieh, Chang-Hsun; Wu, Lawrence Shih-Hsin

    2009-08-01

    Recent studies indicate that obesity may play a key role in modulating genetic predispositions to type 2 diabetes (T2D). This study examines the main effects of both single-locus and multilocus interactions among genetic variants in Taiwanese obese and nonobese individuals to test the hypothesis that obesity-related genes may contribute to the etiology of T2D independently and/or through such complex interactions. We genotyped 11 single nucleotide polymorphisms for 10 obesity candidate genes including adrenergic beta-2-receptor surface, adrenergic beta-3-receptor surface, angiotensinogen, fat mass and obesity associated gene, guanine nucleotide binding protein beta polypeptide 3 (GNB3), interleukin 6 receptor, proprotein convertase subtilisin/kexin type 1 (PCSK1), uncoupling protein 1, uncoupling protein 2, and uncoupling protein 3. There were 389 patients diagnosed with T2D and 186 age- and sex-matched controls. Single-locus analyses showed significant main effects of the GNB3 and PCSK1 genes on the risk of T2D among the nonobese group (p = 0.002 and 0.047, respectively). Further, interactions involving GNB3 and PCSK1 were suggested among the nonobese population using the generalized multifactor dimensionality reduction method (p = 0.001). In addition, interactions among angiotensinogen, fat mass and obesity associated gene, GNB3, and uncoupling protein 3 genes were found in a significant four-locus generalized multifactor dimensionality reduction model among the obese population (p = 0.001). The results suggest that the single nucleotide polymorphisms from the obesity candidate genes may contribute to the risk of T2D independently and/or in an interactive manner according to the presence or absence of obesity.

  18. Gene-Gene Interaction between PPARδ and PPARγ Is Associated with Abdominal Obesity in a Chinese Population

    Institute of Scientific and Technical Information of China (English)

    Yi Ding; Zhi-Rong Guo; Ming Wu; Qiu Chen; Hao Yu; Wen-Shu Luo

    2012-01-01

    The peroxisome proliferator-activated receptors (PPARs) -α,-δ/β and -γ are the ligand-activated transcription factors that function as the master regulators of glucose,fatty acid and lipoprotein metabolism,energy balance,cell proliferation and differentiation,inflammation,and atherosclerosis.The objective of the current study was to examine the main and interactive effect of seven single nucleotide polymorphisms (SNPs) of PPARδ/γ in contribution to abdominal obesity.A total of 820 subjects were randomly selected and no individuals were related.The selected SNPs in PPARδ (rs2016520 and rs9794) and PPARγ (rs10865710,rs1805192,rs709158,rs3856806,and rs4684847) were genotyped.Mean difference and 95% confident interval were calculated.Interactions were explored by the method of generalized multifactor dimensionality reduction.After adjustment for gender,age,and smoking status,it was found that the carriers of the C allele (TC + CC) of rs2016520 were associated with a decreased risk of abdominal obesity compared to the carriers of the TT genotype (mean difference =-2.63,95% CI =-3.61--1.64,P < 0.0001).A significant two-locus model (P =0.0107) involving rs2016520 and rs10865710 and a significant three-locus model (P =0.0107) involving rs2016520,rs9794,and rs1805192 were observed.Overall,the three-locus model had the highest level of testing accuracy (59.85%) and showed a better cross-validation consistency (9/10) than two-locus model.Therefore,for abdominal obesity defined by waist circumference,we chose the three-locus model as the best interaction model.In conclusion,the C allele in rs2016520 was significantly associated with a lower abdominal obesity.Moreover,an interaction among rs2016520,rs1805192,and rs9794 on incident abdominal obesity could be demonstrated.

  19. Multivariate dimensionality reduction approaches to identify gene-gene and gene-environment interactions underlying multiple complex traits.

    Directory of Open Access Journals (Sweden)

    Hai-Ming Xu

    Full Text Available The elusive but ubiquitous multifactor interactions represent a stumbling block that urgently needs to be removed in searching for determinants involved in human complex diseases. The dimensionality reduction approaches are a promising tool for this task. Many complex diseases exhibit composite syndromes required to be measured in a cluster of clinical traits with varying correlations and/or are inherently longitudinal in nature (changing over time and measured dynamically at multiple time points. A multivariate approach for detecting interactions is thus greatly needed on the purposes of handling a multifaceted phenotype and longitudinal data, as well as improving statistical power for multiple significance testing via a two-stage testing procedure that involves a multivariate analysis for grouped phenotypes followed by univariate analysis for the phenotypes in the significant group(s. In this article, we propose a multivariate extension of generalized multifactor dimensionality reduction (GMDR based on multivariate generalized linear, multivariate quasi-likelihood and generalized estimating equations models. Simulations and real data analysis for the cohort from the Study of Addiction: Genetics and Environment are performed to investigate the properties and performance of the proposed method, as compared with the univariate method. The results suggest that the proposed multivariate GMDR substantially boosts statistical power.

  20. A PLSPM-based test statistic for detecting gene-gene co-association in genome-wide association study with case-control design.

    Science.gov (United States)

    Zhang, Xiaoshuai; Yang, Xiaowei; Yuan, Zhongshang; Liu, Yanxun; Li, Fangyu; Peng, Bin; Zhu, Dianwen; Zhao, Jinghua; Xue, Fuzhong

    2013-01-01

    For genome-wide association data analysis, two genes in any pathway, two SNPs in the two linked gene regions respectively or in the two linked exons respectively within one gene are often correlated with each other. We therefore proposed the concept of gene-gene co-association, which refers to the effects not only due to the traditional interaction under nearly independent condition but the correlation between two genes. Furthermore, we constructed a novel statistic for detecting gene-gene co-association based on Partial Least Squares Path Modeling (PLSPM). Through simulation, the relationship between traditional interaction and co-association was highlighted under three different types of co-association. Both simulation and real data analysis demonstrated that the proposed PLSPM-based statistic has better performance than single SNP-based logistic model, PCA-based logistic model, and other gene-based methods.

  1. Gene-environment and gene-gene interactions of specific MTHFR, MTR and CBS gene variants in relation to homocysteine in black South Africans.

    Science.gov (United States)

    Nienaber-Rousseau, Cornelie; Ellis, Suria M; Moss, Sarah J; Melse-Boonstra, Alida; Towers, G Wayne

    2013-11-01

    The methylenetetrahydrofolate reductase (MTHFR), cystathione-β-synthase (CBS) and methionine synthase (MTR) genes interact with each other and the environment. These interactions could influence homocysteine (Hcy) and diseases contingent thereon. We determined single nucleotide polymorphisms (SNPs) within these genes, their relationships and interactions with total Hcy concentrations within black South Africans to address the increased prevalence of diseases associated with Hcy. The MTHFR 677 TT and MTR 2756 AA genotypes were associated with higher Hcy concentrations (16.6 and 10.1 μmol/L; pCBS genotypes did not influence Hcy. We demonstrated interactions between the area of residence and the CBS T833C/844ins68 genotypes (p=0.005) so that when harboring the wildtype allele, rural subjects had significantly higher Hcy than their urban counterparts, but when hosting the variant allele the environment made no difference to Hcy. Between the CBS T833C/844ins68 or G9276A and MTHFR C677T genotypes, there were two-way interactions (p=0.003 and=0.004, respectively), with regard to Hcy. Subjects harboring the MTHFR 677 TT genotype in combination with the CBS 833 TT/homozygous 844 non-insert or the MTHFR 677 TT genotype in combination with the CBS 9276 GA/GG displayed higher Hcy concentrations. Therefore, some of the investigated genotypes affected Hcy; residential area changed the way in which the CBS T833C/844ins68 SNPs influenced Hcy concentrations highlighting the importance of environmental factors; and gene-gene interactions allude to epistatic effects. © 2013 Elsevier B.V. All rights reserved.

  2. Gene-gene interactions between HNF4A and KCNJ11 in predicting Type 2 diabetes in women

    NARCIS (Netherlands)

    Qi, L.; van Dam, R. M.; Asselbergs, F. W.; Hu, F. B.

    2007-01-01

    Aims Recent studies indicate transcription factor hepatocyte nuclear factor 4 alpha ( HNF-4 alpha, HNF4A) modulates the transcription of the pancreatic B-cell ATP-sensitive K+ ( K-ATP) channel subunit Kir6.2 gene ( KCNJ11). Both HNF4A and KCNJ11 have previously been associated with diabetes risk but

  3. Association, haplotype, and gene-gene interactions of the HPA axis genes with suicidal behaviour in affective disorders.

    Science.gov (United States)

    Leszczyńska-Rodziewicz, Anna; Szczepankiewicz, Aleksandra; Pawlak, Joanna; Dmitrzak-Weglarz, Monika; Hauser, Joanna

    2013-01-01

    Family twin and adoption studies have noted the heritability of specific biological factors that influence suicidal behaviour. Exposure to stress is one of the factors that strongly contribute to suicide attempts. The biological response to stress involves the hypothalamic-pituitary-adrenal axis (HPA). Therefore, we found it interesting to study polymorphisms of genes involved in the HPA axis (CRHR1, NR3C1, and AVPBR1). The study was performed on 597 patients, 225 of whom had a history of suicide attempts. We did not observe any significant differences in the studied polymorphisms between the group of patients with a history of suicide attempts and the control subjects. Our haplotype analysis of the AVPR1b gene revealed an association between the GCA haplotype and suicide attempts; however, this association was not significant after correcting for multiple testing. We did not observe any other association in haplotype and MDR analysis. We report here a comprehensive analysis of the HPA axis genes and a lack of association for genetic variations regarding the risk of suicide attempts in affective disorder patients. Nonetheless, the inconsistencies with the previously published results indicate the importance of the further investigation of these polymorphisms with respect to the risk of suicide attempts.

  4. Association, Haplotype, and Gene-Gene Interactions of the HPA Axis Genes with Suicidal Behaviour in Affective Disorders

    Directory of Open Access Journals (Sweden)

    Anna Leszczyńska-Rodziewicz

    2013-01-01

    Full Text Available Family twin and adoption studies have noted the heritability of specific biological factors that influence suicidal behaviour. Exposure to stress is one of the factors that strongly contribute to suicide attempts. The biological response to stress involves the hypothalamic-pituitary-adrenal axis (HPA. Therefore, we found it interesting to study polymorphisms of genes involved in the HPA axis (CRHR1, NR3C1, and AVPBR1. The study was performed on 597 patients, 225 of whom had a history of suicide attempts. We did not observe any significant differences in the studied polymorphisms between the group of patients with a history of suicide attempts and the control subjects. Our haplotype analysis of the AVPR1b gene revealed an association between the GCA haplotype and suicide attempts; however, this association was not significant after correcting for multiple testing. We did not observe any other association in haplotype and MDR analysis. We report here a comprehensive analysis of the HPA axis genes and a lack of association for genetic variations regarding the risk of suicide attempts in affective disorder patients. Nonetheless, the inconsistencies with the previously published results indicate the importance of the further investigation of these polymorphisms with respect to the risk of suicide attempts.

  5. Gene-gene, gene-environment, gene-nutrient interactionsand single nucleotide polymorphisms of inflammatorycytokines

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    Inflammation plays a significant role in the etiologyof type 2 diabetes mellitus (T2DM). The rise in thepro-inflammatory cytokines is the essential step inglucotoxicity and lipotoxicity induced mitochondrialinjury, oxidative stress and beta cell apoptosis inT2DM. Among the recognized markers are interleukin(IL)-6, IL-1, IL-10, IL-18, tissue necrosis factor-alpha(TNF-α), C-reactive protein, resistin, adiponectin, tissueplasminogen activator, fibrinogen and heptoglobins.Diabetes mellitus has firm genetic and very strongenvironmental influence; exhibiting a polygenic modeof inheritance. Many single nucleotide polymorphisms(SNPs) in various genes including those of pro and antiinflammatorycytokines have been reported as a riskfor T2DM. Not all the SNPs have been confirmed byunifying results in different studies and wide variationshave been reported in various ethnic groups. Theinter-ethnic variations can be explained by the factthat gene expression may be regulated by gene-gene,gene-environment and gene-nutrient interactions. Thisreview highlights the impact of these interactions ondetermining the role of single nucleotide polymorphismof IL-6, TNF-α, resistin and adiponectin in pathogenesisof T2DM.

  6. Expression QTL mapping in regulatory and helper T cells from the BXD family of strains reveals novel cell-specific genes, gene-gene interactions and candidate genes for auto-immune disease

    Directory of Open Access Journals (Sweden)

    Alberts Rudi

    2011-12-01

    Full Text Available Abstract Background Regulatory T cells (Tregs play an essential role in the control of the immune response. Treg cells represent important targets for therapeutic interventions of the immune system. Therefore, it will be very important to understand in more detail which genes are specifically activated in Treg cells versus T helper (Th cells, and which gene regulatory circuits may be involved in specifying and maintaining Treg cell homeostasis. Results We isolated Treg and Th cells from a genetically diverse family of 31 BXD type recombinant inbred strains and the fully inbred parental strains of this family--C57BL/6J and DBA/2J. Subsequently genome-wide gene expression studies were performed from the isolated Treg and Th cells. A comparative analysis of the transcriptomes of these cell populations allowed us to identify many novel differentially expressed genes. Analysis of cis- and trans-expression Quantitative Trait Loci (eQTLs highlighted common and unique regulatory mechanisms that are active in the two cell types. Trans-eQTL regions were found for the Treg functional genes Nrp1, Stat3 and Ikzf4. Analyses of the respective QTL intervals suggested several candidate genes that may be involved in regulating these genes in Treg cells. Similarly, possible candidate genes were found which may regulate the expression of F2rl1, Ctla4, Klrb1f. In addition, we identified a focused group of candidate genes that may be important for the maintenance of self-tolerance and the prevention of allergy. Conclusions Variation of expression across the strains allowed us to find many novel gene-interaction networks in both T cell subsets. In addition, these two data sets enabled us to identify many differentially expressed genes and to nominate candidate genes that may have important functions for the maintenance of self-tolerance and the prevention of allergy.

  7. ReliefSeq: a gene-wise adaptive-K nearest-neighbor feature selection tool for finding gene-gene interactions and main effects in mRNA-Seq gene expression data.

    Directory of Open Access Journals (Sweden)

    Brett A McKinney

    Full Text Available Relief-F is a nonparametric, nearest-neighbor machine learning method that has been successfully used to identify relevant variables that may interact in complex multivariate models to explain phenotypic variation. While several tools have been developed for assessing differential expression in sequence-based transcriptomics, the detection of statistical interactions between transcripts has received less attention in the area of RNA-seq analysis. We describe a new extension and assessment of Relief-F for feature selection in RNA-seq data. The ReliefSeq implementation adapts the number of nearest neighbors (k for each gene to optimize the Relief-F test statistics (importance scores for finding both main effects and interactions. We compare this gene-wise adaptive-k (gwak Relief-F method with standard RNA-seq feature selection tools, such as DESeq and edgeR, and with the popular machine learning method Random Forests. We demonstrate performance on a panel of simulated data that have a range of distributional properties reflected in real mRNA-seq data including multiple transcripts with varying sizes of main effects and interaction effects. For simulated main effects, gwak-Relief-F feature selection performs comparably to standard tools DESeq and edgeR for ranking relevant transcripts. For gene-gene interactions, gwak-Relief-F outperforms all comparison methods at ranking relevant genes in all but the highest fold change/highest signal situations where it performs similarly. The gwak-Relief-F algorithm outperforms Random Forests for detecting relevant genes in all simulation experiments. In addition, Relief-F is comparable to the other methods based on computational time. We also apply ReliefSeq to an RNA-Seq study of smallpox vaccine to identify gene expression changes between vaccinia virus-stimulated and unstimulated samples. ReliefSeq is an attractive tool for inclusion in the suite of tools used for analysis of mRNA-Seq data; it has power to

  8. ReliefSeq: a gene-wise adaptive-K nearest-neighbor feature selection tool for finding gene-gene interactions and main effects in mRNA-Seq gene expression data.

    Science.gov (United States)

    McKinney, Brett A; White, Bill C; Grill, Diane E; Li, Peter W; Kennedy, Richard B; Poland, Gregory A; Oberg, Ann L

    2013-01-01

    Relief-F is a nonparametric, nearest-neighbor machine learning method that has been successfully used to identify relevant variables that may interact in complex multivariate models to explain phenotypic variation. While several tools have been developed for assessing differential expression in sequence-based transcriptomics, the detection of statistical interactions between transcripts has received less attention in the area of RNA-seq analysis. We describe a new extension and assessment of Relief-F for feature selection in RNA-seq data. The ReliefSeq implementation adapts the number of nearest neighbors (k) for each gene to optimize the Relief-F test statistics (importance scores) for finding both main effects and interactions. We compare this gene-wise adaptive-k (gwak) Relief-F method with standard RNA-seq feature selection tools, such as DESeq and edgeR, and with the popular machine learning method Random Forests. We demonstrate performance on a panel of simulated data that have a range of distributional properties reflected in real mRNA-seq data including multiple transcripts with varying sizes of main effects and interaction effects. For simulated main effects, gwak-Relief-F feature selection performs comparably to standard tools DESeq and edgeR for ranking relevant transcripts. For gene-gene interactions, gwak-Relief-F outperforms all comparison methods at ranking relevant genes in all but the highest fold change/highest signal situations where it performs similarly. The gwak-Relief-F algorithm outperforms Random Forests for detecting relevant genes in all simulation experiments. In addition, Relief-F is comparable to the other methods based on computational time. We also apply ReliefSeq to an RNA-Seq study of smallpox vaccine to identify gene expression changes between vaccinia virus-stimulated and unstimulated samples. ReliefSeq is an attractive tool for inclusion in the suite of tools used for analysis of mRNA-Seq data; it has power to detect both main

  9. An association study of NRAMP1, VDR, MBL and their interaction with the susceptibility to tuberculosis in a Chinese population

    Directory of Open Access Journals (Sweden)

    Linlin Wu

    2015-09-01

    Conclusions: Our study suggests that genotypes of many polymorphic genes are associated with TB, it is necessary to further explore the mechanism of genotypes and gene-gene interaction in susceptibility to tuberculosis.

  10. Antioxidant Defense Enzyme Genes and Asthma Susceptibility: Gender-Specific Effects and Heterogeneity in Gene-Gene Interactions between Pathogenetic Variants of the Disease

    Directory of Open Access Journals (Sweden)

    Alexey V. Polonikov

    2014-01-01

    Full Text Available Oxidative stress resulting from an increased amount of reactive oxygen species and an imbalance between oxidants and antioxidants plays an important role in the pathogenesis of asthma. The present study tested the hypothesis that genetic susceptibility to allergic and nonallergic variants of asthma is determined by complex interactions between genes encoding antioxidant defense enzymes (ADE. We carried out a comprehensive analysis of the associations between adult asthma and 46 single nucleotide polymorphisms of 34 ADE genes and 12 other candidate genes of asthma in Russian population using set association analysis and multifactor dimensionality reduction approaches. We found for the first time epistatic interactions between ADE genes underlying asthma susceptibility and the genetic heterogeneity between allergic and nonallergic variants of the disease. We identified GSR (glutathione reductase and PON2 (paraoxonase 2 as novel candidate genes for asthma susceptibility. We observed gender-specific effects of ADE genes on the risk of asthma. The results of the study demonstrate complexity and diversity of interactions between genes involved in oxidative stress underlying susceptibility to allergic and nonallergic asthma.

  11. Combined analysis of 19 common validated type 2 diabetes susceptibility gene variants shows moderate discriminative value and no evidence of gene-gene interaction

    DEFF Research Database (Denmark)

    Sparsø, T; Grarup, N; Andreasen, C;

    2009-01-01

    AIMS/HYPOTHESIS: The list of validated type 2 diabetes susceptibility variants has recently been expanded from three to 19. The variants identified are common and have low penetrance in the general population. The aim of the study is to investigate the combined effect of the 19 variants by applyi...... analysis of the 19 validated variants enables detection of subgroups at substantially increased risk of type 2 diabetes; however, the discrimination between glucose-tolerant and type 2 diabetes individuals is still too inaccurate to achieve clinical value....

  12. GeneEd -- A Genetics Educational Resource

    Science.gov (United States)

    ... Javascript on. Feature: Genetics 101 GeneEd — A Genetics Educational Resource Past Issues / Summer 2013 Table of Contents Science ... The Hereditary Material of Life / GeneEd — A Genetics Educational Resource / Using The Genetics Home Reference Website / Understanding the ...

  13. Family-based study of HTR2A in suicide attempts: observed gene, gene × environment and parent-of-origin associations.

    Science.gov (United States)

    Ben-Efraim, Y J; Wasserman, D; Wasserman, J; Sokolowski, M

    2013-07-01

    While suicidal behavior is frequently accompanied by serotonergic system alterations, specific associations with genetic variation in the serotonin 2A receptor (HTR2A) gene have been inconsistent. Using a family-based study design of 660 offspring who have made a suicide attempt (SA) and both parents, we conducted an association and linkage analysis using single-nucleotide polymorphisms (SNPs) with extensive gene coverage, and included the study of parent-of-origin (POE) and gene-environment interaction (G × E), also using previously unstudied exposures. The main finding was a G × E between the exon 1 SNP rs6313 and exposure to cumulative types of lifetime stressful life events (SLEs), driven by overtransmission of CT and undertransmission of TT, both in relation to other genotypes. Further exploratory analysis revealed a significant POE in this G × E in female subjects, which followed a polar overdominant inheritance pattern. In addition, rs6310 and rs6305 were found to significantly associate with SA in the total sample. A G × E in female subjects (rs7322347 × physical assault in childhood/adolescence) confirmed features of a previously observed association with SA. Other potentially interesting nominally significant findings were observed, but like the G × E of rs7322347 did not pass a false-discovery rate cutoff. Taken together, this study found multiple associations of HTR2A SNPs on SA, with strongest statistical evidence for a G × E involving rs6313, and further suggested the importance of taking into account different inheritance patterns and G × Es with regard to HTR2A.

  14. An information-gain approach to detecting three-way epistatic interactions in genetic association studies

    DEFF Research Database (Denmark)

    Hu, Ting; Chen, Yuanzhu; Kiralis, Jeff W;

    2013-01-01

    Background Epistasis has been historically used to describe the phenomenon that the effect of a given gene on a phenotype can be dependent on one or more other genes, and is an essential element for understanding the association between genetic and phenotypic variations. Quantifying epistasis....... In the tuberculosis data, we found a statistically significant pure three-way epistatic interaction effect that was stronger than any lower-order associations. Conclusion Our study provides a methodological basis for detecting and characterizing high-order gene-gene interactions in genetic association studies....

  15. Gene-gene interaction between DNMT3B and DRD1 in schizophrenia%DNA甲基化转移酶3B基因和多巴胺D1受体基因交互作用与精神分裂症的关系

    Institute of Scientific and Technical Information of China (English)

    张晨; 谢斌; 杜亚松; 范娟; 刘漪; 禹顺英; 方贻儒

    2010-01-01

    Objective To identify the impact of gene-gene interaction between DNMT3B and DRD1 on the risk of schizophrenia. Methods Two SNPs (rs2424908 and rs6119954) within DNMT3B and five SNPs (rs4532, rs5326, rs2168631, rs6882300 and rs267418 ) within DRD1 were genotyped in 365 schizophrenic patients and 365 healthy controls. The gene-gene interaction between DNMT3B and DRD1 was analyzed by Multifactor Dimensionality Reduction (MDR) software. Results The frequency of genotypes of rs6119954 within DNMT3B was significantly higher in patients than that in controls (χ2 = 8. 06 ,P =0. 018 ).MDR revealed that the significance were shown in patterns with 2 SNPs ( rs6119954-rs267418 ) ( OR =1.79, 95% CI:1.29-2.47;χ2 =12.51, P=0.0004) , 3 SNPs (rs6119954-rs5326-rs267418) (OR=2. 36, 95% CI: 1.73 - 3.22;χ2 = 29. 33, P < 0. 0001 ) and 4 SNPs ( rs2424908-rs6119954-rs5326-rs267418) (OR=3.08, 95% CI:2.24 -4.24;χ2 =48.88, P<0. 0001). Conclusion The gene-gene interaction between DNMT3B and DRD1 may exist and increase the risk for schizophrenia.%目的 探讨DNA甲基化转移酶3B(DNMT3B)基因与多巴胺D1受体(DRD1)基因交互作用对精神分裂症患病风险的影响.方法 选取DNMT3B基因2个标签SNP(rs2424908和rs6119954)以及DRD1基因5个标签SNP(rs4532、rs5326、rs2168631、rs6882300和rs267418),采用TaqMan探针SNP基因分型技术对365例精神分裂症患者和365名健康对照者进行检测,使用多因子降维法软件(MDR)分析基因-基因交互作用.结果 DNMT3B基因rs6119954位点基因型分布在患者组与对照组之间差异有统计学意义(χ2=8.06,P=0.018);MDR分析结果显示DNMT3B与DRD1基因相互作用存在于两位点模型(rs6119954-rs267418)(OR=1.79,95%CI:1.29~2.47;χ2=12.51,P=0.0004),三位点模型(rs6119954-rs5326-rs267418)(OR=2.36,95%CI:1.73~3.22;χ2=29.33,P<0.0001)以及四位点模型(rs2424908-rs6119954-rs5326-rs267418)(OR=3.08,95% CI:2.24~4.24;χ2=48.88,P<0.0001).结论 DNMT3B与DRD1基因存在交互作

  16. CHRNA7 Polymorphisms and Dementia Risk: Interactions with Apolipoprotein ε4 and Cigarette Smoking

    OpenAIRE

    2016-01-01

    α7 nicotinic acetylcholine receptor (α7nAChR, encoded by CHRNA7) is involved in dementia pathogenesis through cholinergic neurotransmission, neuroprotection and interactions with amyloid-β. Smoking promotes atherosclerosis and increases dementia risk, but nicotine exerts neuroprotective effect via α7nAChR in preclinical studies. No studies explored the gene-gene, gene-environment interactions between CHRNA7 polymorphism, apolipoprotein E (APOE) ε4 status and smoking on dementia risk. This cas...

  17. 多因子降维法在人群散发性结直肠癌交互作用分析中的应用%Application of multifactor dimensionality reduction on the interactions between gene-gene,geneenvironment and the risk sporadic colorectal cancer in Chinese population

    Institute of Scientific and Technical Information of China (English)

    金明娟; 刘冰; 张爽爽; 张勇晶; 徐玫; 马新源; 姚开颜; 陈坤

    2008-01-01

    Objective To identify the association between risk of sporadic colorectal cancer and the common single nucleotide polymorphisms (SNPs) in DNA repairs genes, gene to gene interactions among them and their gene to environment interactions with common environmental factors. Methods In this population-based case-control study, 206 primary colorectal cancer cases and 845 cancer-free healthy controls were enrolled. Genotyping was carried out using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique, with the status of subjects case or controls unknown.Multifactor dimensionality reduction (MDR) and logistic analysis were both used for association analysis.Results As compared to the younger age group (≥42,<61 years), the risk of colorectal cancer in older age group (≥61 years) increased significantly ( OR = 2.04,95% CI: 1.49-2.80). Similar result was observed in the family cancer history ( OR = 1.51, 95% CI : 1.05-2.17 ). However, no significant association between any single DNA repair gene SNP and colorectal cancer risk was discovered. Results from MDR analysis only showed a significant interaction among the four following factors: age, alcohol drinking, XRCC1 Arg194Trp and OGG1 Ser326Cys (the cross-validation consistency = 10/10, the average testing accuracy = 0. 616, P=0.011 ). Using a logistic regression model, the"high-risk"individuals had a significantly elevated risk of colorectal cancer compared to those "low- risk" individuals classified by the above MDR model ( OR = 2.72,95% CI : 1.66-4.47 ). Conclusion The impact of polymorphisms in DNA repair genes on the risk of sporadic colorectal cancer exhibited a low-penetrance characteristics while the intricate interactions existing among them and with environmental factors.%目的 探讨DNA修复基因多态性与中国南方汉族人群散发性结直肠癌发病的相关性,验证多因子降维法(MDR)应用于多因子疾病基因-基因、基因-环境交互

  18. Gene-gene interaction between genes of brain-derived neurotrophic factor and dopamine D1 receptor in schizophrenia%精神分裂症患者脑源性神经营养因子与多巴胺D1受体基因交互作用研究

    Institute of Scientific and Technical Information of China (English)

    卢卫红; 张晨; 易正辉; 吴志国; 陈俊; 方贻儒

    2013-01-01

    目的 探讨多巴胺D1受体(DRD1)与精神分裂症的关系是否与脑源性神经营养因子(BDNF)有关.方法 选取BDNF基因Val66Met位点(rs6562)以及DRD1基因5个标签单核苷酸多态性(SNP)(rs4532、rs5326、rs2168631、rs6882300和rs267418),采用TaqMan探针SNP基因分型技术对340例精神分裂症患者(患者组)和375名健康对照者(对照组)进行检验,使用多因子降维法软件(MDR)分析基因-基因交互作用.结果 以上6个SNP基因型及等位基因频率分布在患者组与对照组之间差异无统计学意义(Ps>0.0083);MDR分析结果显示,BDNF与DRD1基因交互作用存在于两位点模型(rs6265-rs5326)[OR=1.83,95%可信区间(CI):1.33~2.53;x2=13.91,P=0.0002],三位点模型(rs6265-rs4532-rs6882300)(OR=2.06,95% CI:1.53~2.78;x2=22.73,P<0.0001)及四位点模型(rs6265-rs5326-rs2168631-rs6882300)(OR =2.85,95% CI:2.09 ~ 3.89;x2=44.99,P<0.0001).结论 精神分裂症患者BDNF与DRD1基因存在交互作用,DRD1在精神分裂症发生过程中的作用可能与BDNF有关.%Objective To explore the impact of brain-derived neurotrophic factor(BDNF) on the contribution of dopamine D1 receptor (DRD1) to schizophrenia.Methods One single nucleotide polymorphism (SNP) (Va166Met,rs6562) within BDNF gene and five tag-SNPs (rs4532,rs5326,rs2168631,rs6882300 and rs267418) within DRD1 gene were genotyped in 340 schizophrenic patients and 375 healthy controls.The gene-gene interaction between BDNF and DRD1 was analyzed by Multifactor Dimensionality Reduction (MDR) software.Results There were no significant differences on the frequencies of the genotypes and alleles of the six SNPs between patients and controls (Ps > 0.0083).MDR revealed that the significance were shown in patterns with 2 SNPs (rs6265-rs5326; OR =1.83,95% CI:1.33-2.53,x2 =13.91,P =0.0002),3 SNPs (rs6265-rs4532-rs6882300 ; OR =2.06,95% CI:1.53-2.78,x2 =22.73,P < 0.0001) and 4 SNPs (rs6265-rs5326-rs2168631-rs6882300; OR =2.85,95

  19. Using the MPVA Model to Analyze the Impact of Gene-Gene Interaction between CXCR1 and IL8 2789/2862 on the Risk of Mastitis Susceptibility of Chinese Holstein%运用多座位外显方差法分析中国荷斯坦牛CXCR1和IL8基因与乳房炎易感性的关系

    Institute of Scientific and Technical Information of China (English)

    张亚琴; 杨章平; 毛永江; 陈仁金; 陈莹; 冀德君

    2011-01-01

    The aims of this study were to identify the interaction of CXCRl and JL8 and their impacts on the risk of mastitis susceptibility of Chinese Holstein, and to test the feasibility of using Multi-Locus penetrance variance analysis (MPVA) model in analyzing gene-gene interactions. The polymorphisms of 7 SNP sites including the 5' flanking region and coding region of CXCRl and intron 3, exon 4 and exon 5 of IL8 were detected by PCR-SSCP and direct sequencing for 634 Chinese Holstein, including 102 individual with mastitic, from a northern farm of China, and to identify the interaction of CXCRl and IL8 and their impacts on the risk of mastitis susceptibility using MPVA. The interactions of CXCR1-1830-1768-IL8 2789/2862 showed significant effects on the mastitis susceptibility of cow using MPVA model. The results indicate that the interactions of CXCRM830-1768-IL8 2789/2862 is the best multi-genotype model to estimate the risk of mastitis susceptibility of Chinese Holstein. MPVA can be used to estimate the risk of mastitis susceptibility of Chinese Holstein.%旨在运用多座位外显方差分析法(MPVA)分析中国荷斯坦牛CXCR1和IL8两个基因多个突变位点多态性与乳房炎易感性的交互作用.本研究以南方某大型奶牛场634头(其中102头患乳房炎)中国荷斯坦牛为试验材料,采用PCR-SSCP和直接测序法分析CXCR1-5′端和编码区及IL8 2789/2862内含子3、外显子4和5,2个基因共7个SNPs位点的遗传多态性,并用MPVA法分析CXCR1和IL8基因各位点突变及其基因型组合对奶牛乳房炎易感性的影响.结果,MPVA分析发现CXCR1-1830、CXCR1-1768和IL8 2789/2862三位点交互作用对奶牛乳房炎易感性的影响达到显著水平.CXCR1-1830、CXCR1-1768和IL8 2789/2862三位点交互模型作为奶牛乳房炎易感性相关的基因联合选择模型最佳,MPVA可用于奶牛乳房炎易感性多基因分析模型.

  20. A Study on the Interactive

    Directory of Open Access Journals (Sweden)

    Chih-Fang Huang

    2010-05-01

    Full Text Available “Hopscotch” is a world-wide game for children to play since the times in the ancient Roman Empire andChina. Here we present a study mainly focused on the research and discussion of the application on thechildren’s well-know edutainment via the physical interactive design to provide the sensing of the timesfor the conventional hopscotch, which is a new type of experiment for the technology aided edutainment.The innovated hopscotch music game involves the sound samples of various animals and the charactersof cartoon, and the algorithmic composition via the development of the music technology basedinteractive game, to gradually make the children perceive the world of digits, sound, and music. It canguide the growing children’s personality and character from disorder into clarity. Furthermore, thetraditional teaching materials can be improved via the implementation of the electrical sensing devices,electrical I/O module, and the computer music program Max/MSP, to integrate the interactive computermusic with the interactive and immersive soundscapes composition, and the teaching tool witheducational gaming is completely accomplished eventually.

  1. Application of the interaction models between the polymorphism(s) of metabolic gene(s) and environmental exposure%代谢酶基因多态性与环境暴露交互作用的分析方法及其应用

    Institute of Scientific and Technical Information of China (English)

    沈靖; 王润田; 徐希平

    2001-01-01

    目的 以肿瘤易感基因谷胱苷肽-S-转硫酶(GST)M1缺失基因型为例,说明基因与环境暴露交互作用的分析方法以及应用。方法 采用社区为基础的病例对照研究方法,代谢酶基因多态性的检测用PCR技术,资料分析用多因素logistic回归模型。研究对象为1997年1月至1998年12月经扬中市人民医院确诊,肠型胃癌病例112例,以同期该地无上消化道肿瘤的“健康”人群为对照,共675例。结果 调整混杂因素后,GST M1缺失基因型与既往吸烟史的交互作用系数为3.38,OReg值达8.40,有极显著意义,为4型交互作用中的超相乘模型;GST M1缺失基因型与吸烟量的交互作用呈高暴露-基因效应,交互作用系数分别为0.995、2.085和2.157,即随着暴露剂量增加,交互作用强度也逐渐增加;与饮酒量呈低暴露-基因效应,交互作用系数分别为1.01和0.97,交互作用强度随暴露剂量增加而逐渐降低。结论 基于logistic模型的分析方法,可用于评价基因-环境之间的交互作用,以及剂量反应关系的暴露基因效应。%Objective Taking GST M1 as an example to introduce analytic method of interaction models between the polymorphism(s) of metabolic gene(s) and environmental exposure in stomach cancer susceptibility. Methods Using community-based case-control design, combined with molecular biological techniques (PCR) and multiple variables logistic regression models, we analyzed 112 intestinal types of stomach cancer cases with endoscopy and pathology diagnosis in the Yangzhong City Hospital during January 1997 and December 1998. A total of 675 controls were selected from persons who had no history of digestive system cancers. Results After adjustment of confounding variables with both GST M1 null genotype and history of ever tobacco smoking, the results showed a significant types of 4 gene-environment interaction. Interaction index (γ) value

  2. Theoretical studies of molecular interactions

    Energy Technology Data Exchange (ETDEWEB)

    Lester, W.A. Jr. [Univ. of California, Berkeley (United States)

    1993-12-01

    This research program is directed at extending fundamental knowledge of atoms and molecules including their electronic structure, mutual interaction, collision dynamics, and interaction with radiation. The approach combines the use of ab initio methods--Hartree-Fock (HF) multiconfiguration HF, configuration interaction, and the recently developed quantum Monte Carlo (MC)--to describe electronic structure, intermolecular interactions, and other properties, with various methods of characterizing inelastic and reaction collision processes, and photodissociation dynamics. Present activity is focused on the development and application of the QMC method, surface catalyzed reactions, and reorientation cross sections.

  3. Dosage effect of high-amylose modifier gene(s) on the starch structure of maize amylose-extender mutant.

    Science.gov (United States)

    Jiang, Hongxin; Campbell, Mark; Wu, Yusheng; Du, Shuangkui; Srichuwong, Sathaporn; Jane, Jay-Lin

    2015-01-21

    The objective of this study was to investigate how dosages of high-amylose modifier (HAM) gene(s) affected the structure of maize amylose extender (ae) mutant starch. GEMS-0067 (G), a homozygous mutant of ae and the HAM gene(s), and H99ae (H), an ae single mutant, were self-pollinated or inter-crossed to produce maize endosperms of G/G, G/H, H/G, and H/H with 3, 2, 1, and 0 doses of HAM gene(s), respectively. Endosperm starch was fractionated into amylopectin, amylose, and intermediate component (IC) of large and small molecular weights using 1-butanol precipitation of amylose followed by gel-permeation chromatography. Increases in the dosage of HAM gene(s) from 0 to 3 decreased the amylopectin content. The HAM-gene dosage significantly changed the branch chain-length of small-molecular-weight IC, but had little effect on the branch chain-length distributions of amylopectin and large-molecular-weight IC and the molecular structure of amylose.

  4. A maximum likelihood method for studying gene-environment interactions under conditional independence of genotype and exposure.

    Science.gov (United States)

    Cheng, K F

    2006-09-30

    Given the biomedical interest in gene-environment interactions along with the difficulties inherent in gathering genetic data from controls, epidemiologists need methodologies that can increase precision of estimating interactions while minimizing the genotyping of controls. To achieve this purpose, many epidemiologists suggested that one can use case-only design. In this paper, we present a maximum likelihood method for making inference about gene-environment interactions using case-only data. The probability of disease development is described by a logistic risk model. Thus the interactions are model parameters measuring the departure of joint effects of exposure and genotype from multiplicative odds ratios. We extend the typical inference method derived under the assumption of independence between genotype and exposure to that under a more general assumption of conditional independence. Our maximum likelihood method can be applied to analyse both categorical and continuous environmental factors, and generalized to make inference about gene-gene-environment interactions. Moreover, the application of this method can be reduced to simply fitting a multinomial logistic model when we have case-only data. As a consequence, the maximum likelihood estimates of interactions and likelihood ratio tests for hypotheses concerning interactions can be easily computed. The methodology is illustrated through an example based on a study about the joint effects of XRCC1 polymorphisms and smoking on bladder cancer. We also give two simulation studies to show that the proposed method is reliable in finite sample situation.

  5. A membrane - foulant interaction study.

    NARCIS (Netherlands)

    Fontyn, M.

    1991-01-01

    In this thesis the problem of membrane fouling has been considered from different points of view. The aim of the study is to gather information on the physical and chemical mechanisms of membrane fouling, so that selective solutions can be introduced to overcome or to diminish the problem.Anti-foami

  6. Studies on phytoplankton-bacterial interactions

    Digital Repository Service at National Institute of Oceanography (India)

    DeCosta, P.M.

    Given the sheer range of phytoplankton-bacterial interactions, some intriguing aspects have been addressed in this study. Firstly, the role of bacteria in influencing phytoplankton communities at the system level was examined. The seasonal changes...

  7. Case-only study of interactions between metabolic enzymes and smoking in colorectal cancer

    Directory of Open Access Journals (Sweden)

    Zhang Shuangshuang

    2007-06-01

    Full Text Available Abstract Background Gene-gene and gene-environment interactions involved in the metabolism of carcinogens may increase the risk of cancer. Our objective was to measure the interactions between common polymorphisms of P450 (CYP1A2, CYP1B1, CYP2E1, GSTM1 and T1, SULT1A1 and cigarette smoking in colorectal cancer (CRC. Methods A case-only design was conducted in a Chinese population including 207 patients with sporadic CRC. Unconditional logistic regression analysis was performed adjusting for age, gender, alcohol consumption, and cigarette smoking. Results The interaction odds ratio (COR for the gene-gene interaction between CYP1B1 1294G and SULT1A1 638A allele was 2.68 (95% CI: 1.16–6.26. The results of the gene-environment analyses revealed that an interaction existed between cigarette smoking and the CYP1B1 1294G allele for CRC (COR = 2.62, 95%CI: 1.01–6.72, the COR for the interaction of CYP1B1 1294G and smoking history > 35 pack-years was 3.47 (95%CI: 1.12–10.80. No other significant gene-gene and gene-environment interactions were observed. Conclusion Our results showed that the interaction between polymorphisms in CYP1B1 1294G and SULT1A1*2 may play a significant role on CRC in the Chinese population. Also, it is suggested that the association between cigarette smoking and CRC could be differentiated by the CYP1B1 1294G allele.

  8. Study of Carbon Nanotube-Substrate Interaction

    Directory of Open Access Journals (Sweden)

    Jaqueline S. Soares

    2012-01-01

    Full Text Available Environmental effects are very important in nanoscience and nanotechnology. This work reviews the importance of the substrate in single-wall carbon nanotube properties. Contact with a substrate can modify the nanotube properties, and such interactions have been broadly studied as either a negative aspect or a solution for developing carbon nanotube-based nanotechnologies. This paper discusses both theoretical and experimental studies where the interaction between the carbon nanotubes and the substrate affects the structural, electronic, and vibrational properties of the tubes.

  9. Lattice Studies for hadron spectroscopy and interactions

    CERN Document Server

    Aoki, Sinya

    2014-01-01

    Recent progresses of lattice QCD studies for hadron spectroscopy and interactions are briefly reviewed. Some emphasis are given on a new proposal for a method, which enable us to calculate potentials between hadrons. As an example of the method, the extraction of nuclear potential in lattice QCD is discussed in detail.

  10. An Oral Contraceptive Drug Interaction Study

    Science.gov (United States)

    Bradstreet, Thomas E.; Panebianco, Deborah L.

    2004-01-01

    This article focuses on a two treatment, two period, two treatment sequence crossover drug interaction study of a new drug and a standard oral contraceptive therapy. Both normal theory and distribution-free statistical analyses are provided along with a notable amount of graphical insight into the dataset. For one of the variables, the decision on…

  11. An Oral Contraceptive Drug Interaction Study

    Science.gov (United States)

    Bradstreet, Thomas E.; Panebianco, Deborah L.

    2004-01-01

    This article focuses on a two treatment, two period, two treatment sequence crossover drug interaction study of a new drug and a standard oral contraceptive therapy. Both normal theory and distribution-free statistical analyses are provided along with a notable amount of graphical insight into the dataset. For one of the variables, the decision on…

  12. [Semiotic Studies Lab for Patient Care Interactions].

    Science.gov (United States)

    Nunes, Dulce Maria; Portella, Jean Cristtus; Bianchi e Silva, Laura

    2011-12-01

    The aim of this experience report is to present the Semiotic Studies Lab for Patient Care Interactions (Laboratório de Estudos Semióticos nas Interações de Cuidado - LESIC). The lab was set up at the Nursing School of the Federal University of Rio Grande do Sul (UFRGS), Brazil in 2010. It has the purpose of providing didactic and pedagogical updates, based on the Theory developed by the Paris School of Semiotics, that enable the increase of knowledge and interactive/observational skills regarding the nature and mastery of human care.

  13. A Study of Multiplicities in Hadronic Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Estrada Tristan, Nora Patricia; /San Luis Potosi U.

    2006-02-01

    Using data from the SELEX (Fermilab E781) experiment obtained with a minimum-bias trigger, we study multiplicity and angular distributions of secondary particles produced in interactions in the experimental targets. We observe interactions of {Sigma}{sup -}, proton, {pi}{sup -}, and {pi}{sup +}, at beam momenta between 250 GeV/c and 650 GeV/c, in copper, polyethylene, graphite, and beryllium targets. We show that the multiplicity and angular distributions for meson and baryon beams at the same momentum are identical. We also show that the mean multiplicity increases with beam momentum, and presents only small variations with the target material.

  14. Study of Σ~*-Δ Interactions

    Institute of Scientific and Technical Information of China (English)

    DAI Lian-rong; BAI Li-hui; ZHANG He; LIU Jia; FU Yao; TONG De-xin

    2009-01-01

    We study the Σ~*-Δ interaction in the chiral SU(3) quark model and in the extended chiral SU(3) quark model.In these two models,the short-range interaction mechanism are totally different,one is from the one-gluon exchange and another is from the vector meson exchange.The possible reasons of forming strangeness-1 bound states are given.Comparisons between the cases with and without quark exchange effect are made.The results show the quark exchange effect does give attractions to (Σ~*Δ)_(ST)=0 5/2 and (Σ~*Δ)_(ST)=3 1/2 systems,which means the special symmetry is important.Also,we make some analysis on chiral field effect,our results show that the σ exchange dominantly provides the attractive interaction for these two states.

  15. Study of metallothionein-quantum dots interactions.

    Science.gov (United States)

    Tmejova, Katerina; Hynek, David; Kopel, Pavel; Krizkova, Sona; Blazkova, Iva; Trnkova, Libuse; Adam, Vojtech; Kizek, Rene

    2014-05-01

    Nanoparticles have gained increasing interest in medical and in vivo applications. Metallothionein (MT) is well known as a maintainer of metal ions balance in intracellular space. This is due to high affinity of this protein to any reactive species including metals and reactive oxygen species. The purpose of this study was to determine the metallothionein-quantum dots interactions that were investigated by spectral and electrochemical techniques. CuS, CdS, PbS, and CdTe quantum dots (QDs) were analysed. The highest intensity was shown for CdTe, than for CdS measured by fluorescence. These results were supported by statistical analysis and considered as significant. Further, these interactions were analysed using gel electrophoresis, where MT aggregates forming after interactions with QDs were detected. Using differential pulse voltammetry Brdicka reaction, QDs and MT were studied. This method allowed us to confirm spectral results and, moreover, to observe the changes in MT structure causing new voltammetric peaks called X and Y, which enhanced with the prolonged time of interaction up to 6 h.

  16. DNA Interaction Studies of Selected Polyamine Conjugates

    Directory of Open Access Journals (Sweden)

    Marta Szumilak

    2016-09-01

    Full Text Available The interaction of polyamine conjugates with DNA double helix has been studied. Binding properties were examined by ethidium bromide (EtBr displacement and DNA unwinding/topoisomerase I/II (Topo I/II activity assays, as well as dsDNA thermal stability studies and circular dichroism spectroscopy. Genotoxicity of the compounds was estimated by a comet assay. It has been shown that only compound 2a can interact with dsDNA via an intercalative binding mode as it displaced EtBr from the dsDNA-dye complex, with Kapp = 4.26 × 106 M−1; caused an increase in melting temperature; changed the circular dichroism spectrum of dsDNA; converted relaxed plasmid DNA into a supercoiled molecule in the presence of Topo I and reduced the amount of short oligonucleotide fragments in the comet tail. Furthermore, preliminary theoretical study has shown that interaction of the discussed compounds with dsDNA depends on molecule linker length and charge distribution over terminal aromatic chromophores.

  17. DNA Interaction Studies of Selected Polyamine Conjugates

    Science.gov (United States)

    Szumilak, Marta; Merecz, Anna; Strek, Malgorzata; Stanczak, Andrzej; Inglot, Tadeusz W.; Karwowski, Boleslaw T.

    2016-01-01

    The interaction of polyamine conjugates with DNA double helix has been studied. Binding properties were examined by ethidium bromide (EtBr) displacement and DNA unwinding/topoisomerase I/II (Topo I/II) activity assays, as well as dsDNA thermal stability studies and circular dichroism spectroscopy. Genotoxicity of the compounds was estimated by a comet assay. It has been shown that only compound 2a can interact with dsDNA via an intercalative binding mode as it displaced EtBr from the dsDNA-dye complex, with Kapp = 4.26 × 106 M−1; caused an increase in melting temperature; changed the circular dichroism spectrum of dsDNA; converted relaxed plasmid DNA into a supercoiled molecule in the presence of Topo I and reduced the amount of short oligonucleotide fragments in the comet tail. Furthermore, preliminary theoretical study has shown that interaction of the discussed compounds with dsDNA depends on molecule linker length and charge distribution over terminal aromatic chromophores. PMID:27657041

  18. Study of vehicular interactions in heterogeneous traffic

    Energy Technology Data Exchange (ETDEWEB)

    Arasan, V.T.; Krishnamurthy, K. [Indian Inst. of Technology, Madras, Chennai (India). Dept. of Civil Engineering

    2007-07-01

    In planning, design and operation of road systems, knowledge of traffic flow characteristics and the associated analytical techniques is necessary. Traffic flow represents the traffic load on the road and the interaction between these loadings and the facility capacity determines the operational performance of the system. This paper presented the results of a study that examined the basic characteristics of heterogeneous traffic flow on Indian city roads through extensive traffic surveys; revalidated the indigenously developed simulation model of heterogeneous traffic flow on mid block sections of urban roads for application of the model to study the interaction between vehicles over a wide range of traffic flow conditions; and, quantified the vehicular interactions in terms of Passenger Car Units (PCU) by applying the validated simulation model for a wide range of traffic flow conditions. The paper provided some background information on road traffic in India and discussed the simulation model and input variables. It also discussed model validation and application. It was concluded that the simulation model of heterogeneous traffic, when validated, replicated the field observed traffic flow to a satisfactory extent and that the Passenger Car Unit value of different types of vehicles varied significantly with variation in traffic volume. 9 refs., 6 tabs., 9 figs.

  19. Francium Spectroscopy for Weak Interaction Studies

    Science.gov (United States)

    Orozco, Luis

    2014-05-01

    Francium, a radioactive element, is the heaviest alkali. Its atomic and nuclear structure makes it an ideal laboratory to study the weak interaction. Laser trapping and cooling in-line with the superconducting LINAC accelerator at Stony Brook opened the precision study of its atomic structure. I will present our proposal and progress towards weak interaction measurements at TRIUMF, the National Canadian Accelerator in Vancouver. These include the commissioning run of the Francium Trapping Facility, hyperfine anomaly measurements on a chain of Fr isotopes, the nuclear anapole moment through parity non-conserving transitions in the ground state hyperfine manifold. These measurements should shed light on the nucleon-nucleon weak interaction. This work is done by the FrPNC collaboration: S. Aubin College of William and Mary, J. A. Behr TRIUMF, R. Collister U. Manitoba, E. Gomez UASLP, G. Gwinner U. Manitoba, M. R. Pearson TRIUMF, L. A. Orozco UMD, M. Tandecki TRIUMF, J. Zhang UMD Supported by NSF and DOE from the USA; TRIUMF, NRC and NSERC from Canada; and CONACYT from Mexico

  20. Molecular interaction studies using microscale thermophoresis.

    Science.gov (United States)

    Jerabek-Willemsen, Moran; Wienken, Chistoph J; Braun, Dieter; Baaske, Philipp; Duhr, Stefan

    2011-08-01

    Abstract The use of infrared laser sources for creation of localized temperature fields has opened new possibilities for basic research and drug discovery. A recently developed technology, Microscale Thermophoresis (MST), uses this temperature field to perform biomolecular interaction studies. Thermophoresis, the motion of molecules in temperature fields, is very sensitive to changes in size, charge, and solvation shell of a molecule and thus suited for bioanalytics. This review focuses on the theoretical background of MST and gives a detailed overview on various applications to demonstrate the broad applicability. Experiments range from the quantification of the affinity of low-molecular-weight binders using fluorescently labeled proteins, to interactions between macromolecules and multi-component complexes like receptor containing liposomes. Information regarding experiment and experimental setup is based on the Monolith NT.115 instrument (NanoTemper Technologies GmbH).

  1. A fluvoxamine-caffeine interaction study

    DEFF Research Database (Denmark)

    Jeppesen, U; Loft, S; Poulsen, H E

    1996-01-01

    The selective serotonin reuptake inhibitor fluvoxamine is a very potent inhibitor of the liver enzyme CYP1A2, which is the major P450 catalysing the biotransformation of caffeine. Thus, a pharmacokinetic study was undertaken with the purpose of documenting a drug-drug interaction between fluvoxam......The selective serotonin reuptake inhibitor fluvoxamine is a very potent inhibitor of the liver enzyme CYP1A2, which is the major P450 catalysing the biotransformation of caffeine. Thus, a pharmacokinetic study was undertaken with the purpose of documenting a drug-drug interaction between...... fluvoxamine and caffeine. The study was carried out as a randomized, in vivo, cross-over study including eight healthy volunteers. In Period A of the study, each subject took 200 mg caffeine orally, and in Period B, the subjects took fluvoxamine 50 mg per day for 4 days and 100 mg per day for 8 days. On day 8...... in Period B, the subjects again ingested 200 mg caffeine. After caffeine intake, blood and urine were sampled at regular intervals. Caffeine and its three primary demethylated metabolites, paraxanthine, theobromine and theophylline in plasma and the same four compounds plus 11 more metabolites in urine were...

  2. Strong interaction studies with kaonic atoms

    Directory of Open Access Journals (Sweden)

    Marton J.

    2016-01-01

    Full Text Available The strong interaction of antikaons (K− with nucleons and nuclei in the low-energy regime represents an active research field connected intrinsically with few-body physics. There are important open questions like the question of antikaon nuclear bound states - the prototype system being K−pp. A unique and rather direct experimental access to the antikaon-nucleon scattering lengths is provided by precision X-ray spectroscopy of transitions in low-lying states of light kaonic atoms like kaonic hydrogen isotopes. In the SIDDHARTA experiment at the electron-positron collider DAΦNE of LNF-INFN we measured the most precise values of the strong interaction observables, i.e. the strong interaction on the 1s ground state of the electromagnetically bound K−p atom leading to a hadronic shift ϵ1s and a hadronic broadening Γ1s of the 1s state. The SIDDHARTA result triggered new theoretical work which achieved major progress in the understanding of the low-energy strong interaction with strangeness. Antikaon-nucleon scattering lengths have been calculated constrained by the SIDDHARTA data on kaonic hydrogen. For the extraction of the isospin-dependent scattering lengths a measurement of the hadronic shift and width of kaonic deuterium is necessary. Therefore, new X-ray studies with the focus on kaonic deuterium are in preparation (SIDDHARTA2. Many improvements in the experimental setup will allow to measure kaonic deuterium which is challenging due to the anticipated low X-ray yield. Especially important are the data on the X-ray yields of kaonic deuterium extracted from a exploratory experiment within SIDDHARTA.

  3. Combustion of Interacting Droplet Arrays Being Studied

    Science.gov (United States)

    Dietrich, Daniel L.

    2002-01-01

    The combustion of liquid fuels is a major source of energy in the world today, and the majority of these fuels are burned in the form of a spray. This droplet combustion project at the NASA Glenn Research Center has the overall goal of providing a better understanding of spray combustion by extending existing studies of single droplets to a regime where droplet interactions are important (as occurs in a practical spray). The Combustion of Interacting Droplet Arrays is a collaborative effort between Glenn and the National Center for Microgravity Research. The group at Glenn also collaborates with scientists at the National Institute of Advanced Industrial Science and Technology in Hokkaido, Japan. The project is studying the combustion of a small number of droplets suspended on small quartz fibers in a 0.1-atm combustion chamber. Data consist primarily of video images of the flames and droplets. The tests are being conducted in Glenn's reduced-gravity facilities (2.2-sec and 5.2-sec drop towers) and in the Japan Microgravity Center's 10-sec drop tower (JAMIC).

  4. Interactivity with the interactive whiteboard in traditional and innovative primary schools: an exploratory study

    NARCIS (Netherlands)

    de Koster, S.; Volman, M.; Kuiper, E.

    2013-01-01

    One of the main affordances of the interactive whiteboard (IWB) is its potential for increasing classroom interactivity, yet little is known about the interactivity it supports in schools with different educational concepts. In this study we analysed what types of whole-class interactivity the IWB s

  5. Photon interaction studies using 241Am -rays

    Indian Academy of Sciences (India)

    N Ramachandran; K Karunakaran Nair; K K Abdullah; K M Varier

    2006-09-01

    We have carried out some photon interaction measurements using 59.54 keV -rays from a 241Am source. These include attenuation studies as well as photoelectric absorption studies in various samples. The attenuation studies have been made using leaf and wood samples, samples like sand, sugar etc., which contain particles of varying sizes as well as pellets and aqueous solutions of rare earth compounds. In the case of the leaf and wood samples, we have used the -ray attenuation technique for the determination of the water content in fresh and dried samples. The variation of the attenuation coefficient with particle size has been investigated for sand and sugar samples. The attenuation studies as well as the photoelectric studies in the case of rare earth elements have been carried out on samples containing such elements whose K-absorption edge energies lie below and close to the -energy used. Suitable compounds of the rare earth elements have been chosen as mixture absorbers in these investigations. A narrow beam good geometry set-up was used for the attenuation measurements. A well-shielded scattering geometry was used for the photoelectric measurements. The mixture rule was invoked to extract the values of the mass attenuation coefficients for the elements from those of the corresponding compounds. The results are consistent with theoretical values derived from the XCOM package.

  6. Interaction Between Flames and Electric Fields Studied

    Science.gov (United States)

    Yuan, Zeng-Guang; Hegde, Uday

    2003-01-01

    The interaction between flames and electric fields has long been an interesting research subject that has theoretical importance as well as practical significance. Many of the reactions in a flame follow an ionic pathway: that is, positive and negative ions are formed during the intermediate steps of the reaction. When an external electric field is applied, the ions move according to the electric force (the Coulomb force) exerted on them. The motion of the ions modifies the chemistry because the reacting species are altered, it changes the velocity field of the flame, and it alters the electric field distribution. As a result, the flame will change its shape and location to meet all thermal, chemical, and electrical constraints. In normal gravity, the strong buoyant effect often makes the flame multidimensional and, thus, hinders the detailed study of the problem.

  7. Study of electron-positron interactions

    Energy Technology Data Exchange (ETDEWEB)

    Abashian, A.; Gotow, K.; Philonen, L.

    1990-09-15

    For the past seven years, this group has been interested in the study of tests of the Standard Model of Electroweak interactions. The program has centered about the AMY experiment which examines the nature of the final state products in electron-positron collisions in the center of mass energy range near 60 GeV. Results of these measurements have shown a remarkable consistency with the predictions of the minimal model of 3 quark and lepton generations and single charged and neutral intermediate bosons. No new particles or excited states have been observed nor has any evidence for departures in cross sections or angular asymmetries from expectations been observed. These conclusions have been even more firmly established by the higher energy results from the LEP and SLC colliders at center of mass energies of about 90 GeV. Our focus is shifting to the neutrino as a probe to electroweak interactions. The relative merit of attempting to observe neutrinos from point sources versus observing neutrinos generally is not easy to predict. The improved ability to interpret is offset by the probably episodic nature of the emission and irreproducibility of the results. In this phase of development, it is best to be sensitive to both sources of neutrinos. As a second phase of our program at Virginia Tech, we are studying the feasibility of detecting cosmic ray neutrinos in a proposed experiment which we have called NOVA. the results of the test setup will be instrumental in developing an optimum design. A third program we are involved in is the MEGA experiment at Los Alamos, an experiment to place a limit on the rate of muon decay to electron plus photon which is forbidden by the Standard Model.

  8. Polymorphisms in metabolic genes, their combination and interaction with tobacco smoke and alcohol consumption and risk of gastric cancer: A case-control study in an Italian population

    NARCIS (Netherlands)

    S. Boccia (Stefania); F.A. Sayed-Tabatabaei (Fakhredin); R. Persiani (Roberto); F. Gianfagna (Francesco); S. Rausei (Stefano); D. Arzani (Dario); A. La Greca (Antonio); D. D'Ugo (Domenico); G. La Torre (Giuseppe); P. Tikka-Kleemola (Päivi); G. Ricciardi (Gualtiero)

    2007-01-01

    textabstractBackground: The distribution and the potential gene-gene and gene-environment interaction of selected metabolic genetic polymorphisms was investigated in relation to gastric cancer risk in an Italian population. Methods: One hundred and seven cases and 254 hospital controls, matched by

  9. Entrez Gene: gene-centered information at NCBI.

    Science.gov (United States)

    Maglott, Donna; Ostell, Jim; Pruitt, Kim D; Tatusova, Tatiana

    2011-01-01

    Entrez Gene (http://www.ncbi.nlm.nih.gov/gene) is National Center for Biotechnology Information (NCBI)'s database for gene-specific information. Entrez Gene maintains records from genomes which have been completely sequenced, which have an active research community to submit gene-specific information, or which are scheduled for intense sequence analysis. The content represents the integration of curation and automated processing from NCBI's Reference Sequence project (RefSeq), collaborating model organism databases, consortia such as Gene Ontology and other databases within NCBI. Records in Entrez Gene are assigned unique, stable and tracked integers as identifiers. The content (nomenclature, genomic location, gene products and their attributes, markers, phenotypes and links to citations, sequences, variation details, maps, expression, homologs, protein domains and external databases) is available via interactive browsing through NCBI's Entrez system, via NCBI's Entrez programming utilities (E-Utilities) and for bulk transfer by FTP.

  10. Contributions of renin-angiotensin system-related gene interactions to obesity in a Chinese population.

    Directory of Open Access Journals (Sweden)

    Jian-Bo Zhou

    Full Text Available BACKGROUND: Gene-gene interactions may be partly responsible for complex traits such as obesity. Increasing evidence suggests that the renin-angiotensin system (RAS contributes to the etiology of obesity. How the epistasis of genes in the RAS contributes to obesity is still under research. We aim to evaluate the contribution of RAS-related gene interactions to a predisposition of obesity in a Chinese population. METHODOLOGY AND PRINCIPAL FINDINGS: We selected six single nucleotide polymorphisms (SNPs located in angiotensin (AGT, angiotensin converting enzyme (ACE, angiotensin type 1 receptor (AGTR1, MAS1, nitric oxide synthase 3 (NOS3 and the bradykinin B2 receptor gene (BDKRB2, and genotyped them in 324 unrelated individuals with obesity (BMI ≥ 28 kg/m(2 and 373 non-obese controls (BMI 18.5 to <24 kg/m(2 from a large scale population-based cohort. We analyzed gene-gene interactions among 6 polymorphic loci using the Generalized Multifactor Dimensionality Reduction (GMDR method, which has been shown to be effective for detecting gene-gene interactions in case-control studies with relatively small samples. Then we used logistic regression models to confirm the best combination of loci identified in the GMDR. It showed a significant gene-gene interaction between the rs220721 polymorphism in the MAS1 gene and the rs1799722 polymorphism in the gene BDKB2R. The best two-locus combination scored 9 for cross-validation consistency and 9 for sign test (p = 0.0107. This interaction showed the maximum consistency and minimum prediction error among all gene-gene interaction models evaluated. Moreover, the combination of the MAS1 rs220721 and the BDKRB2 rs1799722 was associated with a significantly increased risk of obesity (OR 1.82, CI 95%: 1.15-2.88, p = 0.0103. CONCLUSIONS AND SIGNIFICANCE: These results suggest that the SNPs from the RAS-related genes may contribute to the risk of obesity in an interactive manner in a Chinese population. The gene-gene

  11. Interactions: A Study of Office Reference Statistics

    Directory of Open Access Journals (Sweden)

    Naomi Lederer

    2012-06-01

    Full Text Available Objective – The purpose of this study was to analyze the data from a referencestatistics-gathering mechanism at Colorado State University (CSU Libraries. It aimedprimarily to better understand patron behaviours, particularly in an academic librarywith no reference desk.Methods – The researchers examined data from 2007 to 2010 of College LiaisonLibrarians’ consultations with patrons. Data were analyzed by various criteria,including patron type, contact method, and time spent with the patron. Theinformation was examined in the aggregate, meaning all librarians combined, andthen specifically from the Liberal Arts and Business subject areas.Results – The researchers found that the number of librarian reference consultationsis substantial. Referrals to librarians from CSU’s Morgan Library’s one public servicedesk have declined over time. The researchers also found that graduate students arethe primary patrons and email is the preferred contact method overall.Conclusion – The researchers found that interactions with patrons in librarians’ offices – either in person or virtually – remain substantial even without a traditional reference desk. The data suggest that librarians’ efforts at marketing themselves to departments, colleges, and patrons have been successful. This study will be of value to reference, subject specialist, and public service librarians, and library administrators as they consider ways to quantify their work, not only for administrative purposes, but in order to follow trends and provide services and staffing accordingly.

  12. Pharmacokinetic interaction study between ranitidine and metoclopramide.

    Science.gov (United States)

    Leucuţa, Adrian; Vlase, Laurian; Farcău, Dorin; Nanulescu, Mircea

    2004-09-01

    The pharmacokinetics of metoclopramide in healthy volunteers was evaluated to determine if previously repeated doses of ranitidine inhibit the metabolism of the gastrointestinal prokinetic drug. Metoclopramide 20 mg (tablets) in combination with ranitidine 150 mg (tablets) were administered to 14 healthy human volunteers in a two treatment study design, separated by 5 days in which the ranitidine alone was administrated in single p.o. doses twice daily. Plasma concentrations of metoclopramide were determined during a 24 hour period following drug administration. Metoclopramide plasma concentrations were determined by a validated RP-HPLC method. Pharmacokinetic parameters were calculated with compartmental and non-compartmental analysis. In the two periods of treatments, the mean peak plasma concentrations Cmax were 44 ng/ml (metoclopramide alone) and 49.2 ng/ml (metoclopramide and ranitidine). The time taken to reach the peak, Tmax, was 1.15 hrs, and 1.21 hrs, respectively. The total areas under the curve (AUC) was 314.3 ng.hr/ml and 354.06 ng.hr/ml, respectively. The half-life (T 1/2) was 5.6 hr and 6.7 hr. A statistically significant difference was observed for both AUC and half-life of metoclopramide when administered alone or after 5 days of treatment with ranitidine. The experimental data proved the pharmacokinetic interaction between ranitidine of metoclopramide, and suggest monitoring adverse effects in patients.

  13. Gene-Gene and Gene-Environment Interactions in the Etiology of Breast Cancer

    Science.gov (United States)

    2007-06-01

    taking any oral contraceptives and then resumed, ask questions D1- D2 again) D2 . Name of the oral contraceptive D3 . Age of first use D4. Duration...June 2007). “The multipotent influence of Vitamin D on breast cancer risk”. D.R. Marshall (PI), primary submitter with Dr. Alecia Malin-Fair (PI), co...Portion Size 170. Pepper 1 2 3 4 5 171. Chili/Hot 1 2 3 4 5 172. Salt 1 2 3 4 5 173. Vitamins and Supplements 1 2 3 4 5 174. Others 1 2 3 4 5

  14. Gene-gene and gene-environment interactions in prostate, breast and colorectal cancer

    OpenAIRE

    Kopp, Tine Iskov; Vogel, Ulla Birgitte; Nellemann, Christine; Ravn-Haren, Gitte; Tjønneland, Anne

    2015-01-01

    Cancer incidensen i Vesten er steget stødt de sidste 50 år. For tre af de mest prævalente cancer typer i Danmark, prostata-, bryst- og kolorektal cancer, er kun en lille del (1-15%) af incidensen forårsaget af højpenetrans enkelt-genmutationer pga. deres lave frekvens i populationen. Generelt set bidrager nedarvede faktorer til årsagsforhold for bryst cancer kun med 27%, hvorimod genetik bidrager med 35% og 42% for henholdsvis kolorektal- og prostata cancer. Derudover indikerer immigrationsst...

  15. Systematic Search for Gene-Gene Interaction Effect on Prostate Cancer Risk

    Science.gov (United States)

    2013-07-01

    J., Chang, B.L., Elmore, J.B., Breyer, J.P., McReynolds, K.M., Bradley, K.M., Yaspan, B.L., Wiklund, F., Stattin, P., Lindstrom , S., Adami, H.O...deficiency disrupts normal lymphatic vasculature formation and causes lymphedema. EMBO J, 22, 3546-56. 53. Martin -Villar, E., Scholl, F.G., Gamallo, C

  16. Gene-Gene Associations with the Susceptibility of Kawasaki Disease and Coronary Artery Lesions.

    Directory of Open Access Journals (Sweden)

    Ho-Chang Kuo

    Full Text Available Kawasaki disease (KD is a systemic vasculitis primarily affecting children < 5 years old. Genes significantly associated with KD mostly involve cardiovascular, immune, and inflammatory responses. Recent studies have observed stronger associations for KD risk with multiple genes compared to individual genes. Therefore, we investigated whether gene combinations influenced KD susceptibility or coronary artery lesion (CAL formation. We examined 384 single-nucleotide polymorphisms (SNPs for 159 immune-related candidate genes in DNA samples from KD patients with CAL (n = 73, KD patients without CAL (n = 153, and cohort controls (n = 575. Individual SNPs were first assessed by univariate analysis (UVA and multivariate analysis (MVA. We used multifactor dimensionality reduction (MDR to examine individual SNPs in one-, two-, and three-locus best fit models. UVA identified 53 individual SNPs that were significantly associated with KD risk or CAL formation (p < 0.10, while 35 individual SNPs were significantly associated using MVA (p ≤ 0.05. Significant associations in MDR analysis were only observed for the two-locus models after permutation testing (p ≤ 0.05. In logistic regression, combined possession of PDE2A (rs341058 and CYFIP2 (rs767007 significantly increased KD susceptibility (OR = 3.54; p = 4.14 x 10(-7, while combinations of LOC100133214 (rs2517892 and IL2RA (rs3118470 significantly increased the risk of CAL in KD patients (OR = 5.35; p = 7.46 x 10(-5. Our results suggest varying gene-gene associations respectively predispose individuals to KD risk or its complications of CAL.

  17. Virus-membrane interactions: spectroscopic studies.

    NARCIS (Netherlands)

    Datema, K.P.

    1987-01-01

    In this thesis some new aspects of the infection process of nonenveloped viruses are reported. The interaction of a rod-shaped (TMV) and three spherical (CCMV, BMV, SBMV) plant viruses, of the filamentous bacteriophage M13, and of their coat proteins with membranes have been investigated. A comparis

  18. Strong interaction studies with kaonic atoms

    CERN Document Server

    Marton, J; Beer, G; Berucci, C; Bosnar, D; Bragadireanu, A M; Cargnelli, M; Clozza, A; Curceanu, C; d'Uffizi, A; Fiorini, C; Ghio, F; Guaraldo, C; Hayano, R; Iliescu, M; Ishiwatari, T; Iwasaki, M; Sandri, P Levi; Okada, S; Pietreanu, D; Piscicchia, K; Ponta, T; Quaglia, R; Vidal, A Romero; Sbardella, E; Scordo, A; Shi, H; Sirghi, D L; Sirghi, F; Tatsuno, H; Doce, O Vazquez; Widmann, E; Zmeskal, J

    2016-01-01

    The strong interaction of antikaons with nucleons and nuclei in the low-energy regime represents an active research field connected intrinsically with few-body physics. There are important open questions like the question of antikaon nuclear bound states. A unique and rather direct experimental access to the antikaon-nucleon scattering lengths is provided by precision X-ray spectroscopy of transitions in low-lying states of light kaonic atoms like kaonic hydrogen isotopes. In the SIDDHARTA experiment at the electron-positron collider DAFNE of LNF-INFN we measured the most precise values of the strong interaction observables, i.e. the strong interaction on the 1s ground state of the electromagnetically bound kaonic hydrogen atom leading to a hadronic shift and a hadronic broadening of the 1s state. The SIDDHARTA result triggered new theoretical work which achieved major progress in the understanding of the low-energy strong interaction with strangeness. Antikaon-nucleon scattering lengths have been calculated ...

  19. Strong interaction studies with kaonic atoms

    CERN Document Server

    Marton, J; Beer, G; Berucci, C; Bosnar, D; Bragadireanu, A M; Cargnelli, M; Clozza, A; Curceanu, C; d'Uffizi, A; Fiorini, C; Ghio, F; Guaraldo, C; Hayano, R; Iliescu, M; Ishiwatari, T; Iwasaki, M; Sandri, P Levi; Okada, S; Pietreanu, D; Piscicchia, K; Ponta, T; Quaglia, R; Vidal, A Romero; Sbardella, E; Scordo, A; Shi, H; Sirghi, D L; Sirghi, F; Tatsuno, H; Doce, O Vazquez; Widmann, E; Zmeskal, J

    2015-01-01

    The strong interaction of antikaons (K-) with nucleons and nuclei in the low energy regime represents an active research field connected intrinsically with few-body physics. There are important open questions like the question of antikaon nuclear bound states - the prototype system being K-pp. A unique and rather direct experimental access to the antikaon-nucleon scattering lengths is provided by precision X-ray spectroscopy of transitions in low-lying states of light kaonic atoms like kaonic hydrogen isotopes. In the SIDDHARTA experiment at the electron-positron collider DA?NE of LNF-INFN we measured the most precise values of the strong interaction observables, i.e. the strong interaction on the 1s ground state of the electromagnetically bound K-p atom leading to a hadronic shift and a hadronic broadening of the 1s state. The SIDDHARTA result triggered new theoretical work which achieved major progress in the understanding of the low-energy strong interaction with strangeness. Antikaon-nucleon scattering le...

  20. Interactive social neuroscience to study autism spectrum disorder.

    Science.gov (United States)

    Rolison, Max J; Naples, Adam J; McPartland, James C

    2015-03-01

    Individuals with autism spectrum disorder (ASD) demonstrate difficulty with social interactions and relationships, but the neural mechanisms underlying these difficulties remain largely unknown. While social difficulties in ASD are most apparent in the context of interactions with other people, most neuroscience research investigating ASD have provided limited insight into the complex dynamics of these interactions. The development of novel, innovative "interactive social neuroscience" methods to study the brain in contexts with two interacting humans is a necessary advance for ASD research. Studies applying an interactive neuroscience approach to study two brains engaging with one another have revealed significant differences in neural processes during interaction compared to observation in brain regions that are implicated in the neuropathology of ASD. Interactive social neuroscience methods are crucial in clarifying the mechanisms underlying the social and communication deficits that characterize ASD.

  1. Flicker Interaction Studies and Flickermeter Improvement

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Rong

    2009-06-04

    types are made in the PQ lab of TUE since the human eye is sensitive to the light color. The measurement results are analyzed by FFT (Fast Fourier Transform) and the wavelength contributions to flicker of different lamp types are presented in this thesis. It provides important information on the light color variation of different lamp types under flicker conditions. Weighting factors of various lamp types are obtained by the corresponding wavelength contribution to the flicker weighted with the CIE photopic luminosity curve. These weighting factors indicate the human eye flicker response from the human eye spectrum sensitivity point of view. Then it is possible to develop a simplified flicker measurement method for different lamp types by adding an eye-brain flicker response model. A discussion about the simplified flicker measurement method and the eye-brain model is given in this thesis. Finally, the interaction between flicker and dimmers (the phase controlled dimmer and reverse phase controlled dimmer) is studied based on experimental work. The measurement results show that the phase controlled dimmer will increase the flicker problem. Solutions to avoid the flicker influence of dimmers are discussed in this thesis.

  2. Strong Interaction Studies with PANDA at FAIR

    Directory of Open Access Journals (Sweden)

    Schönning Karin

    2016-01-01

    Full Text Available The Facility for Antiproton and Ion Research (FAIR in Darmstadt, Germany, provides unique possibilities for a new generation of nuclear-, hadron- and atomic physics experiments. The future PANDA experiment at FAIR will offer a broad physics programme with emphasis on different aspects of hadron physics. Understanding the strong interaction in the perturbative regime remains one of the greatest challenges in contemporary physics and hadrons provide several important keys. In these proceedings, PANDA will be presented along with some high-lights of the planned physics programme.

  3. Strong Interaction Studies with PANDA at FAIR

    Science.gov (United States)

    Schönning, Karin

    2016-10-01

    The Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany, provides unique possibilities for a new generation of nuclear-, hadron- and atomic physics experiments. The future PANDA experiment at FAIR will offer a broad physics programme with emphasis on different aspects of hadron physics. Understanding the strong interaction in the perturbative regime remains one of the greatest challenges in contemporary physics and hadrons provide several important keys. In these proceedings, PANDA will be presented along with some high-lights of the planned physics programme.

  4. A Study on the Input Hypothesis and Interaction Hypothesis

    Institute of Scientific and Technical Information of China (English)

    李雪清

    2016-01-01

    In Second Language Acquisition theory, input and interaction are considered as two key factors greatly influencing the learners’acquisition rate and quality, and therefore input and interaction research has been receiving increasing attention in re-cent years. Among the large amount of research, Krashen’s input hypothesis and Long’s interaction hypothesis are perhaps most influential theories, from which most of input and interaction studies have developed. Input hypothesis claims that compre-hensible input is the only one way to acquire language, whereas interaction hypothesis argues that interaction is necessary for language acquisition. Therefore,this thesis attempts to conduct a descriptive analysis between input hypothesis and interaction hypothesis, based on their basic ideas, theoretical basis, comparisons and empirical work. It concludes that input hypothesis and interaction hypothesis succeed in interpreting the process of language acquisition to some extent, and offer both theoretical and practical inspirations on second language teaching.

  5. A simple model for studying interacting networks

    Science.gov (United States)

    Liu, Wenjia; Jolad, Shivakumar; Schmittmann, Beate; Zia, R. K. P.

    2011-03-01

    Many specific physical networks (e.g., internet, power grid, interstates), have been characterized in considerable detail, but in isolation from each other. Yet, each of these networks supports the functions of the others, and so far, little is known about how their interactions affect their structure and functionality. To address this issue, we consider two coupled model networks. Each network is relatively simple, with a fixed set of nodes, but dynamically generated set of links which has a preferred degree, κ . In the stationary state, the degree distribution has exponential tails (far from κ), an attribute which we can explain. Next, we consider two such networks with different κ 's, reminiscent of two social groups, e.g., extroverts and introverts. Finally, we let these networks interact by establishing a controllable fraction of cross links. The resulting distribution of links, both within and across the two model networks, is investigated and discussed, along with some potential consequences for real networks. Supported in part by NSF-DMR-0705152 and 1005417.

  6. Intermolecular interaction studies of glyphosate with water

    Science.gov (United States)

    Manon, Priti; Juglan, K. C.; Kaur, Kirandeep; Sethi, Nidhi; Kaur, J. P.

    2017-07-01

    The density (ρ), viscosity (η) and ultrasonic velocity (U) of glyphosate with water have been measured on different ultrasonic frequency ranges from 1MHz, 2MHz, 3MHz & 5MHz by varying concentrations (0.05%, 0.10%, 0.15%, 0.20%, 0.25%, 0.30%, 0.35%, & 0.40%) at 30°C. The specific gravity bottle, Ostwald's viscometer and quartz crystal interferometer were used to determine density (ρ), viscosity (η) and ultrasonic velocity (U). These three factors contribute in evaluating the other parameters as acoustic impedance (Z), adiabatic compressibility (β), relaxation time (τ), intermolecular free length (Lf), free volume (Vf), ultrasonic attenuation (α/f2), Rao's constant (R), Wada's constant (W) and relative strength (R). Solute-solvent interaction is confirmed by ultrasonic velocity and viscosity values, which increases with increase in concentration indicates stronger association between solute and solvent molecules. With rise in ultrasonic frequency the interaction between the solute and solvent particles decreases. The linear variations in Rao's constant and Wada's constant suggest the absence of complex formation.

  7. Interactions among the glucocorticoid receptor, lipoprotein lipase and adrenergic receptor genes and abdominal fat in the Québec Family Study.

    Science.gov (United States)

    Ukkola, O; Pérusse, L; Chagnon, Y C; Després, J P; Bouchard, C

    2001-09-01

    To investigate whether interactions between glucocorticoid receptor (GRL), lipoprotein lipase (LPL) and adrenergic receptor (ADR) gene markers contribute to individual differences in indicators of adiposity and abdominal obesity, including visceral fat level. Cross-sectional study; 742 individuals from the phase 2 of the Québec Family Study cohort. Total body fat assessed by hydrodensitometry and the sum of six skinfolds. Abdominal fat areas measured by computed tomography and adjusted for age, sex and total fat mass in all analyses. GRL Bcl I, alpha 2A-ADR Dra I and beta 2-ADR Ban I markers were typed by Southern blot, and other markers by polymerase chain reaction technique. It is confirmed that the 4.5 kb allele of the GRL BclI polymorphism is associated with a higher amount of abdominal visceral fat (AVF) depot (P for trend<0.001) independent of the level of total body fat. Furthermore, the alpha 2-ADR Dra I variant is associated with lower cross-sectional areas of abdominal total (P=0.003) and subcutaneous (P=0.012) adipose tissue. Gene-gene interactions between GRL and alpha 2-ADR genes affecting overall adiposity (P=0.016) as well as between GRL and beta 2-ADR genes (P=0.049) having influence on total abdominal fat levels were observed. When the three genes were considered together in the same analysis, significant interactions having influence on overall adiposity (P=0.017), abdominal total (P=0.032) and visceral fat (P=0.002) were observed. About 1-2% of the total variation in total fatness and abdominal fat was explained by these gene-gene interactions. There is an association between the GRL BclI polymorphism and increased AVF levels independent of the level of total body fat. The alpha 2-ADR DraI variant is associated with a lower cross-sectional area of abdominal total fat. Numerous interactions between GRL and ADR markers on overall adiposity and total abdominal fat as well as between GRL, LPL and ADR genes on overall adiposity, abdominal total and

  8. Gene–Environment Interaction: Definitions and Study Designs

    OpenAIRE

    Ottman, Ruth

    1996-01-01

    Study of gene–environment interaction is important for improving accuracy and precision in the assessment of both genetic and environmental influences. This overview presents a simple definition of gene–environment interaction and suggests study designs for detecting it. Gene–environment interaction is defined as “a different effect of an environmental exposure on disease risk in persons with different genotypes,” or, alternatively, “a different effect of a genotype on disease risk in persons...

  9. The Interaction Network Ontology-supported modeling and mining of complex interactions represented with multiple keywords in biomedical literature.

    Science.gov (United States)

    Özgür, Arzucan; Hur, Junguk; He, Yongqun

    2016-01-01

    The Interaction Network Ontology (INO) logically represents biological interactions, pathways, and networks. INO has been demonstrated to be valuable in providing a set of structured ontological terms and associated keywords to support literature mining of gene-gene interactions from biomedical literature. However, previous work using INO focused on single keyword matching, while many interactions are represented with two or more interaction keywords used in combination. This paper reports our extension of INO to include combinatory patterns of two or more literature mining keywords co-existing in one sentence to represent specific INO interaction classes. Such keyword combinations and related INO interaction type information could be automatically obtained via SPARQL queries, formatted in Excel format, and used in an INO-supported SciMiner, an in-house literature mining program. We studied the gene interaction sentences from the commonly used benchmark Learning Logic in Language (LLL) dataset and one internally generated vaccine-related dataset to identify and analyze interaction types containing multiple keywords. Patterns obtained from the dependency parse trees of the sentences were used to identify the interaction keywords that are related to each other and collectively represent an interaction type. The INO ontology currently has 575 terms including 202 terms under the interaction branch. The relations between the INO interaction types and associated keywords are represented using the INO annotation relations: 'has literature mining keywords' and 'has keyword dependency pattern'. The keyword dependency patterns were generated via running the Stanford Parser to obtain dependency relation types. Out of the 107 interactions in the LLL dataset represented with two-keyword interaction types, 86 were identified by using the direct dependency relations. The LLL dataset contained 34 gene regulation interaction types, each of which associated with multiple keywords. A

  10. Determinants of Internet Use for Interactive Learning: An Exploratory Study

    Science.gov (United States)

    Castaño, Jonatan; Duart, Josep M.; Sancho-Vinuesa, Teresa

    2015-01-01

    The use of the Internet in higher education teaching can facilitate the interactive learning process and thus improve educational outcomes. The aim of the study presented here is to explore which variables are linked to higher intensity of Internet-based interactive educational practices. The study is based on data obtained from an online survey…

  11. The experimental study of interaction between shock wave and turbulence

    Institute of Scientific and Technical Information of China (English)

    ZHAO YuXin; YI ShiHe; HE Lin; CHENG ZhongYu; TIAN LiFeng

    2007-01-01

    The interaction between shock wave and turbulence has been studied in supersonic turbulent mix layer wind tunnel. The interaction between oblique shock wave and turbulent boundary layer and the influence of large vortex in mix layer on oblique shock wave have been observed by NPLS technique. From NPLS image, not only complex flow structure is observed but also time-dependent supersonic flow visualization is realized. The mechanism of interaction between shock wave and turbulence is discussed based on high quality NPLS image.

  12. Molecular Cloning of Human Gene(s) Directing the Synthesis of Nervous System Cholinesterases

    Science.gov (United States)

    1987-09-01

    Report No. 4 If MOLECULAR CLONING OF O HUMAN GENE(S) DIRECTING qTHE SYNTHESIS OF NERVOUS SYSTEM CHOLINESTERASES cc Annual/Final Report 0 N November...62734A I734A875 IAl 451 MOLECULAR CLONING OF HUMAN GEME(S) DIRECTING THE SYNTHESIS OF NERVOUS SYSTEM CHOLINESTERASE 12. PERSONAL AUTHOR(S) Hermona Soreq...important roles in regulating the pace and mode of function of particular types of synapses. For example, molecular cloning of the nicotinic (44-46) and the

  13. Studying Complex Interactions in Real Time

    DEFF Research Database (Denmark)

    2017-01-01

    The study of human behavior must take into account the social context, and real-time, networked experiments with multiple participants is one increasingly popular way to achieve this. In this paper a framework based on Python and XMPP is presented that aims to make it easy to develop such behavio...

  14. A Study of Teacher-Learner Interactions: A Continuum Between Monologic and Dialogic Interactions.

    Science.gov (United States)

    Kathard, Harsha; Pillay, Daisy; Pillay, Mershen

    2015-07-01

    Teachers and learners must be able to shift flexibly along the continuum of monologic and dialogic interactional repertoires to advance learning. This article describes how teachers and learners interacted during whole-class instruction along the continuum between monologic and dialogic interaction in primary school classrooms in Western Cape, South Africa. A video-observation method was used to analyze teacher-learner interactions (TLIs) across 15 lessons in intermediate-phase classrooms. TLIs were analyzed in relation to indicators such as authority, questions, feedback, explanation, metalevel connection, and collaboration. The transcriptions of TLIs were described using quantitative and qualitative techniques. The study found that teachers sustained dominant monologic interactions by asserting their authority, asking mainly closed-ended questions, and providing confirming/correcting feedback that constrained the interaction. Learners had limited opportunities for explanations or collaboration. Across most lessons, there were episodic shifts from monologic TLIs to transitional TLIs. These transitions were achieved by using mainly open-ended questions and feedback to expand the interaction. Dialogic TLIs were not evident. Monologic TLIs were dominant, closing down opportunities for communication. Although transitional TLIs were evident, they were episodic and showed the potential for opening interaction opportunities. The absence of dialogic TLIs suggested that collaborative engagement opportunities were unavailable. The opportunity for intervention to increase dialogic TLIs is discussed.

  15. STUDY OF SWEPT SHOCK WAVE AND BOUNDARY LAYER INTERACTIONS

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    This paper presents briefly the recent progress on study of swept shock wave/boundary layer interactions with emphasis on application of zonalanalysis and correlation analysis to them. Based on the zonal analysis an overall framework of complicated interaction flow structure including both surface flowfield and space flowfield is discussed. Based on correlation analysis the conical interactions induced by four families of shock wave generators have been discussedin detail. Some control parameter and physical mechanism of conical interaction have been revealed. Finally some aspects of the problem and the prospects for future work are suggested.

  16. Structural study of surfactant-dependent interaction with protein

    Energy Technology Data Exchange (ETDEWEB)

    Mehan, Sumit; Aswal, Vinod K., E-mail: vkaswal@barc.gov.in [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Kohlbrecher, Joachim [Laboratory for Neutron Scattering, Paul Scherrer Institut, CH-5232 PSI Villigen (Switzerland)

    2015-06-24

    Small-angle neutron scattering (SANS) has been used to study the complex structure of anionic BSA protein with three different (cationic DTAB, anionic SDS and non-ionic C12E10) surfactants. These systems form very different surfactant-dependent complexes. We show that the structure of protein-surfactant complex is initiated by the site-specific electrostatic interaction between the components, followed by the hydrophobic interaction at high surfactant concentrations. It is also found that hydrophobic interaction is preferred over the electrostatic interaction in deciding the resultant structure of protein-surfactant complexes.

  17. A theoretical study on interaction of proline with gold cluster

    Indian Academy of Sciences (India)

    Sandhya Rai; N V Suresh Kumar; Harjinder Singh

    2012-06-01

    Interaction of proline with gold cluster was studied using density functional theory (DFT). Two types of mixed basis sets UB3LYP/6-311++G ∪ LANL2MB and UB3LYP/6-311++G ∪ LANL2DZ were used for optimization of complex structures. Proline interacts with gold cluster either through one anchor bond, N–Au or an anchor bond O–Au associated with a non-conventional O–H…Au hydrogen bond. Among these interactions, higher tendency for interaction is seen with Au cluster through amide terminal. Natural bond orbital analysis (NBO) is used to substantiate the results.

  18. Study of molecular interactions with 13C DNP-NMR.

    Science.gov (United States)

    Lerche, Mathilde H; Meier, Sebastian; Jensen, Pernille R; Baumann, Herbert; Petersen, Bent O; Karlsson, Magnus; Duus, Jens Ø; Ardenkjaer-Larsen, Jan H

    2010-03-01

    NMR spectroscopy is an established, versatile technique for the detection of molecular interactions, even when these interactions are weak. Signal enhancement by several orders of magnitude through dynamic nuclear polarization alleviates several practical limitations of NMR-based interaction studies. This enhanced non-equilibrium polarization contributes sensitivity for the detection of molecular interactions in a single NMR transient. We show that direct (13)C NMR ligand binding studies at natural isotopic abundance of (13)C gets feasible in this way. Resultant screens are easy to interpret and can be performed at (13)C concentrations below muM. In addition to such ligand-detected studies of molecular interaction, ligand binding can be assessed and quantified with enzymatic assays that employ hyperpolarized substrates at varying enzyme inhibitor concentrations. The physical labeling of nuclear spins by hyperpolarization thus provides the opportunity to devise fast novel in vitro experiments with low material requirement and without the need for synthetic modifications of target or ligands.

  19. Study of interaction between shock wave and unsteady boundary layer

    Institute of Scientific and Technical Information of China (English)

    董志勇; 韩肇元

    2003-01-01

    This paper reports theoretical and experimental study of a new type of interaction of a moving shock wave with an unsteady boundary layer. This type of shock wave-boundary layer interaction describes a moving shock wave interaction with an unsteady boundary layer induced by another shock wave and a rarefaction wave. So it is different from the interaction of a stationary shock wave with steady boundary layer, also different from the interaction of a reflected moving shock wave at the end of a shock tube with unsteady boundary layer induced by an incident shock. Geometrical shock dynamics is used for the theoretical analysis of the shock wave-unsteady boundary layer interaction, and a double-driver shock tube with a rarefaction wave bursting diaphragm is used for the experimental investigation in this work.

  20. SAXS studies of ion-nucleic acid interactions.

    Science.gov (United States)

    Pollack, Lois

    2011-01-01

    Positively charged ions, atoms, or molecules compensate the high negative charge of the nucleic acid backbone. Their presence is critical to the biological function of DNA and RNA. This review focuses on experimental studies probing (a) interactions between small ions and nucleic acids and (b) ion-mediated interactions between nucleic acid duplexes. Experimental results on these simple model systems can be compared with specific theoretical models to validate their predictions. Small angle X-ray scattering (SAXS) provides unique insight into these interactions. Anomalous SAXS reports the spatial correlations of condensed (e.g., locally concentrated) counterions to individual DNA or RNA duplexes. SAXS very effectively reports interactions between nucleic acid helices, which range from strongly repulsive to strongly attractive depending on the ionic species present. The sign and strength of interparticle interactions are easily deduced from dramatic changes in the scattering profiles of interacting duplexes.

  1. Seating Position and Interaction in Triads: A Field Study

    Science.gov (United States)

    Silverstein, C. Harris; Stang, David J.

    1976-01-01

    Relationships between seating position, length of acquaintance between subjects, observer bias toward the experimental outcome, and interaction rates are examined in a field study. Subjects with greatest visual centrality spoke most often. Length of acquaintance between subjects was unrelated to interaction rates. (Author/DEP)

  2. A Usability Study of Interactive Web-Based Modules

    Science.gov (United States)

    Girard, Tulay; Pinar, Musa

    2011-01-01

    This research advances the understanding of the usability of marketing case study modules in the area of interactive web-based technologies through the assignment of seven interactive case modules in a Principles of Marketing course. The case modules were provided for marketing students by the publisher, McGraw Hill Irwin, of the…

  3. Pharmacogenomic study using bio- and nanobioelectrochemistry: Drug-DNA interaction.

    Science.gov (United States)

    Hasanzadeh, Mohammad; Shadjou, Nasrin

    2016-04-01

    Small molecules that bind genomic DNA have proven that they can be effective anticancer, antibiotic and antiviral therapeutic agents that affect the well-being of millions of people worldwide. Drug-DNA interaction affects DNA replication and division; causes strand breaks, and mutations. Therefore, the investigation of drug-DNA interaction is needed to understand the mechanism of drug action as well as in designing DNA-targeted drugs. On the other hand, the interaction between DNA and drugs can cause chemical and conformational modifications and, thus, variation of the electrochemical properties of nucleobases. For this purpose, electrochemical methods/biosensors can be used toward detection of drug-DNA interactions. The present paper reviews the drug-DNA interactions, their types and applications of electrochemical techniques used to study interactions between DNA and drugs or small ligand molecules that are potentially of pharmaceutical interest. The results are used to determine drug binding sites and sequence preference, as well as conformational changes due to drug-DNA interactions. Also, the intention of this review is to give an overview of the present state of the drug-DNA interaction cognition. The applications of electrochemical techniques for investigation of drug-DNA interaction were reviewed and we have discussed the type of qualitative or quantitative information that can be obtained from the use of each technique.

  4. Monte Carlo studies on neutron interactions in radiobiological experiments.

    Science.gov (United States)

    Shahmohammadi Beni, Mehrdad; Hau, Tak Cheong; Krstic, D; Nikezic, D; Yu, K N

    2017-01-01

    Monte Carlo method was used to study the characteristics of neutron interactions with cells underneath a water medium layer with varying thickness. The following results were obtained. (1) The fractions of neutron interaction with 1H, 12C, 14N and 16O nuclei in the cell layer were studied. The fraction with 1H increased with increasing medium thickness, while decreased for 12C, 14N and 16O nuclei. The bulges in the interaction fractions with 12C, 14N and 16O nuclei were explained by the resonance spikes in the interaction cross-section data. The interaction fraction decreased in the order: 1H > 16O > 12C > 14N. (2) In general, as the medium thickness increased, the number of "interacting neutrons" which exited the medium and then further interacted with the cell layer increased. (3) The area under the angular distributions for "interacting neutrons" decreased with increasing incident neutron energy. Such results would be useful for deciphering the reasons behind discrepancies among existing results in the literature.

  5. Experimental and Numerical Studies of Atmosphere Water Interactions

    KAUST Repository

    Bou-Zeid, Elie

    2011-07-04

    Understanding and quantifying the interaction of the atmosphere with underlying water surfaces is of great importance for a wide range of scientific fields such as water resources management, climate studies of ocean-atmosphere exchange, and regional weat

  6. Fragment molecular orbital method for studying lanthanide interactions with proteins

    Energy Technology Data Exchange (ETDEWEB)

    Tsushima, Satoru [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Biophysics; Komeiji, Y. [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba (Japan); Mochizuki, Y. [Rikkyo Univ., Tokyo (Japan)

    2017-06-01

    The binding affinity of the calcium-binding protein calmodulin towards Eu{sup 3+} was studied as a model for lanthanide protein interactions in the large family of ''EF-hand'' calcium-binding proteins.

  7. Game theory and experimental games the study of strategic interaction

    CERN Document Server

    Colman, Andrew M

    1982-01-01

    Game Theory and Experimental Games: The Study of Strategic Interaction is a critical survey of the essential ideas of game theory and the findings of empirical research on strategic interaction. Some experiments using lifelike simulations of familiar kinds of strategic interactions are presented, and applications of game theory to the study of voting, the theory of evolution, and moral philosophy are discussed.Comprised of 13 chapters, this volume begins with an informal definition of game theory and an outline of the types of social situations to which it applies. Games of skill, games of cha

  8. Polymorphisms in metabolic genes, their combination and interaction with tobacco smoke and alcohol consumption and risk of gastric cancer: a case-control study in an Italian population

    Science.gov (United States)

    Boccia, Stefania; Sayed-Tabatabaei, Fakhredin A; Persiani, Roberto; Gianfagna, Francesco; Rausei, Stefano; Arzani, Dario; La Greca, Antonio; D'Ugo, Domenico; La Torre, Giuseppe; van Duijn, Cornelia M; Ricciardi, Gualtiero

    2007-01-01

    Background The distribution and the potential gene-gene and gene-environment interaction of selected metabolic genetic polymorphisms was investigated in relation to gastric cancer risk in an Italian population. Methods One hundred and seven cases and 254 hospital controls, matched by age and gender, were genotyped for CYP1A1, CYP2E1, mEH, GSTM1, GSTT1, NAT2 and SULT1A1 polymorphisms. Haplotype analysis was performed for EPHX1 exons 3 and 4, as well as CYP2E1 RsaI (*5 alleles) and CYP2E1 DraI (*5A or *6 alleles). The effect modification by alcohol and cigarette smoking was tested with the heterogeneity test, while the attributable proportion (AP) was used to measure the biological interaction from the gene-gene interaction analysis. Results Gastric cancer risk was found to be associated with the inheritance of GSTT1 null genotype (OR = 2.10, 95%CI: 1.27–3.44) and the SULT1A1 His/His genotype (OR = 2.46, 95%CI: 1.03–5.90). No differences were observed for the haplotype distributions among cases and controls. For the first time an increased risk was detected among individuals carrying the *6 variant allele of CYP2E1 if ever-drinkers (OR = 3.70; 95%CI: 1.45–9.37) with respect to never-drinkers (OR = 0.18; 95% CI: 0.22–1.46) (p value of heterogeneity among the two estimates = 0.001). Similarly, the effect of SULT1A1 variant genotype resulted restricted to ever-smokers, with an OR of 2.58 (95%CI: 1.27–5.25) for the carriers of His allele among smokers, and an OR of 0.86 (95%CI: 0.45–1.64) among never-smokers (p value of heterogeneity among the two estimates = 0.03). The gene-gene interaction analyses demonstrated that individuals with combined GSTT1 null and NAT2 slow acetylators had an additional increased risk of gastric cancer, with an OR of 3.00 (95%CI: 1.52–5.93) and an AP of 52%. Conclusion GSTT1, SULT1A1 and NAT2 polymorphisms appear to modulate individual's susceptibility to gastric cancer in this Italian population, particularly when more than one

  9. Interaction of SynaptotagminⅠ with Phospholipid Membrane: A Monolayer Study

    Institute of Scientific and Technical Information of China (English)

    贺雨虹; 隋森芳

    2002-01-01

    Synaptotagmin Ⅰ(sytⅠ) is an abundant integral membrane protein of the synaptic vesicle and the C2A domain is an important functional domain in the cytoplasmic part of sytⅠ. C2A prefers to interact with plasmic membranes of neuron cells in vivo and such interaction is closely related to the sytⅠ physiological function as a Ca2+ sensor in the Ca2+-regulated neurotransmitter release. However, the interaction nature between C2A and phospholipids is not well understood. Monolayers at an air/water interface were used to study the interaction between C2A and a phospholipid membrane. The results show that C2A preferentially inserts into the negatively charged phosphatidylserine monolayer and Ca2+ ions are required for the interaction. Electrostatic force is mostly responsible for the insertion of C2A into dipalmitoyl phosphatidylserine monolayers.

  10. STUDY OF IDENTIFICATION AND ASSESSMENT OF DRUG - DRUG INTERACTIONS

    Directory of Open Access Journals (Sweden)

    Shekar

    2014-02-01

    Full Text Available INTRODUCTION : Drug – drug interactions can be defined as pharmacological or clinical respons e to the administration of drug combination s that is different from its known effects of two or more than two medicines. It frequently conjures images of a sudden catastrophic and even fatal outcome. While such an event can occur and it is important to prevent in the clinical set up. Drug interactio ns can occur by pharmacokinetic & pharmacodynamic interactions. The antipsychotics are known to have more drug interactions compared to any other class of drugs hence we aimed for the identification of drug interactions of psychiatric drugs. METHODOLOGY : T he data was collected from medication chart of inpatients in the psychiatric department and analyzed the interactions using Stockley’s drug interactions , Dipiro etc. RESULTS AND DISCUSSION : The study includes 508 samples out of which 368 case were found to have interactions. The cobalamine and panto prazole interactions were found to be 36.14% and the combination of antipsychotics , anticonvulsants with anxiolytics and anticonvulsants were 10.22 %

  11. Environmental confounding in gene-environment interaction studies.

    Science.gov (United States)

    Vanderweele, Tyler J; Ko, Yi-An; Mukherjee, Bhramar

    2013-07-01

    We show that, in the presence of uncontrolled environmental confounding, joint tests for the presence of a main genetic effect and gene-environment interaction will be biased if the genetic and environmental factors are correlated, even if there is no effect of either the genetic factor or the environmental factor on the disease. When environmental confounding is ignored, such tests will in fact reject the joint null of no genetic effect with a probability that tends to 1 as the sample size increases. This problem with the joint test vanishes under gene-environment independence, but it still persists if estimating the gene-environment interaction parameter itself is of interest. Uncontrolled environmental confounding will bias estimates of gene-environment interaction parameters even under gene-environment independence, but it will not do so if the unmeasured confounding variable itself does not interact with the genetic factor. Under gene-environment independence, if the interaction parameter without controlling for the environmental confounder is nonzero, then there is gene-environment interaction either between the genetic factor and the environmental factor of interest or between the genetic factor and the unmeasured environmental confounder. We evaluate several recently proposed joint tests in a simulation study and discuss the implications of these results for the conduct of gene-environment interaction studies.

  12. A comparative study of polymer-dye interaction

    Directory of Open Access Journals (Sweden)

    Nandini R.

    2009-08-01

    Full Text Available The interaction between an anionic dye Methyl Orange and two poly cations namely, Poly (N-vinyl-4-methylpyridiniumiodide, (PC1 & Poly (vinylbenzyltriphenylphosphoniumchloride, (PC2 has been investigated by spectrophotometric method. The polymers are observed to induce metachromasy in the dye as evidenced from the considerable blue shift in the absorption maximum of the dye. The interaction constant and thermodynamic parameters of interaction have been determined by absorbance measurements at the metachromatic band. The effect of additives such as ionic salts, alcohols, urea and polyelectrolytes on the reversal of metachromasy has been studied and used to determine the stability of the metachromatic complex and to understand the nature of binding.

  13. Interweaving interactions in virtual worlds: a case study.

    Science.gov (United States)

    Cantamesse, Matteo; Galimberti, Carlo; Giacoma, Gianandrea

    2011-01-01

    The aim of this study was to examine the effect of playing the online game World of Warcraft (WoW), both on adolescent's (effective) social interaction and on the competence they developed on it. Social interactions within the game environment have been investigated by integrating qualitative and quantitative methods: conversation analysis and social network analysis (SNA). From a psychosocial point of view, the in-game interactions, and in particular conversational exchanges, turn out to be a collaborative path of the joint definition of identities and social ties, with reflection on in-game processes and out-game relationship.

  14. The pragmatics of therapeutic interaction: an empirical study.

    Science.gov (United States)

    Lepper, Georgia

    2009-10-01

    The research reported in this article aims to demonstrate a method for the systematic study of the therapist/patient interaction in psychoanalytic psychotherapy, drawing upon the tradition and methods of 'pragmatics'--the study of language in interaction. A brief introduction to the discipline of pragmatics demonstrates its relevance to the contemporary focus of clinical theory on the here-and-now dynamics of the relationship between analyst and patient. This is followed by a detailed study of five segments from the transcript of a therapeutic dialogue, drawn from a brief psychoanalytic psychotherapy, in which therapist and patient negotiate the meaning of the patient's symptom: Is it psychosomatic? The research seeks to show how the therapeutic process can be observed and studied as an interactional achievement, grounded in general and well-studied procedures through which meaning is intersubjectively developed and shared. Implications of the analysis for clinical theory and practice, and further research, are discussed.

  15. A comparative study of interaction of ibuprofen with biocompatible polymers.

    Science.gov (United States)

    Khan, Iqrar A; Anjum, Kahkashan; Ali, Mohd Sajid; Kabir-ud Din

    2011-11-01

    In this paper we are reporting the interaction of a non-steroidal anti-inflammatory drug ibuprofen (IBF) with various biocompatible polymers. Being amphiphilic, the drug interacts with the polymers similar to the interaction of surfactants and polymers. Therefore, we have considered the polymer-amphiphile interaction approach using conductimetry. The polymers of different charges (cationic, anionic, and nonionic) have been taken for the study. It was found that the critical aggregation concentration (cac) decreases on increasing the polymer concentrations of cationic as well as nonionic polymers whereas it increases for anionic polymers. The results imply that anionic IBF interacts with cationic and nonionic polymers more strongly as compared to the anionic polymers. A possible anionic-anionic repulsion is responsible for the weak interaction of IBF with anionic polymers. On the other side, the critical micelle concentration (cmc) increases for all polymers which is a usual indication of the interaction between amphiphiles and polymers. Free energies of aggregation (ΔG(agg)) and micellization (ΔG(mic)) were also computed with the help of degrees of micelle ionization obtained from the specific conductivity - [IBF] isotherms.

  16. [Expression of rice dwarf virus outer coat protein gene(S8) in insect cells].

    Science.gov (United States)

    Li, S; Liu, H; Chen, Z; Li, Y

    2001-04-01

    Outer coat protein gene(S8) of RDV was cloned into the transfer vector pVL 1393 to construct a recombinant vector pVL1393-S8. The recombinant vector pVL1393-S8 and the linear baculovirus RP23. LacZ were cotransfected into sf9 cells to produce the recombinant virus RP23-S8. RP23-S8 infected sf9 cells were collected and analysed by SDS-PAGE and Western-blot. The results showed that the S8 gene of RDV was expressed in sf9 cells and the expression level of sf9 cells was higher between 72-96 h after infected.

  17. Isospin symmetry violation, meson production and -nucleus interaction studies

    Indian Academy of Sciences (India)

    B J Roy; V Jha; A Chatterje; H Machner; GEM Collaboration

    2006-05-01

    We have studied isospin symmetry violation in nuclear reactions by measuring simultaneously the cross-section of the following two reactions + → 3H + and + → 3He 0. The experiment was perfomed at the cooler synchrotron accelerator. COSY, Jülich at several beam energies close to the corresponding production threshold. We also have ongoing programmes on -nucleus final-state interaction studies via + 6Li → 7Be + reactions, high resolution search for dibaryonic resonances and lambda-proton final state interaction studies. The experimental details and results obtained so far are presented here.

  18. Studies on melt-water-structure interaction during severe accidents

    Energy Technology Data Exchange (ETDEWEB)

    Sehgal, B.R.; Dinh, T.N.; Okkonen, T.J.; Bui, V.A.; Nourgaliev, R.R.; Andersson, J. [Royal Inst. of Technology, Div. of Nucl. Power Safety, Stockholm (Sweden)

    1996-10-01

    Results of a series of studies, on melt-water-structure interactions which occur during the progression of a core melt-down accident, are described. The emphasis is on the in-vessel interactions and the studies are both experimental and analytical. Since, the studies performed resulted in papers published in proceedings of the technical meetings, and in journals, copies of a set of selected papers are attached to provide details. A summary of the results obtained is provided for the reader who does not, or cannot, venture into the perusal of the attached papers. (au).

  19. Numerical study of the laminar shock boundary layer interaction

    Science.gov (United States)

    Katzer, E.

    1985-02-01

    The interaction of an oblique shock wave with a laminar boundary layer on an adiabatic flat plate was analyzed numerically with solutions of the two dimensional Navier-Stokes equations using McCormack's explicit finite volume method. The agreement between numerical calculations and experimental results is good. Local and global properties of the interaction region are discussed regarding shock strength, separation bubble length using a similarity law, and separation environment. The asymetrical structure inside the separation bubble produces an asymetrical shape of the wall shear stress distribution. The calculation speed was increased by algorithm vectorization on a CRAY 1S supercomputer. Further investigations for determination of a similarity law in interaction with turbulent boundary layer, of the physical mechanisms of the laminar interaction, and for study of the wall temperature transfer are recommended.

  20. A spectroscopic study of interaction of cationic dyes with heparin

    Directory of Open Access Journals (Sweden)

    R. Nandini

    2010-01-01

    Full Text Available The interaction of two cationic dyes namely, acridine orange and pinacyanol chloride with an anionic polyelectrolyte, heparin, has been investigated by spectrophotometric method.The polymer induced metachromasy in the dyes resulting in the shift of the absorption maxima of the dyes towards shorter wavelengths. The stability of the complexes formed between acridine orange and heparin was found to be lesser than that formed between pinacyanol chloride and heparin. This fact was further confirmed by reversal studies using alcohols, urea and surfactants. The interaction of acridine orange with heparin has also been investigated fluorimetrically.The interaction parameters revealed that binding between acridine orange and heparin arises due to electrostatic interaction while that between pinacyanol chloride and heparin is found to involve both electrostatic and hydrophobic forces. The effect of the structure of the dye in inducing metachromasy has also been discussed.

  1. Social signal processing for studying parent–infant interaction

    Science.gov (United States)

    Avril, Marie; Leclère, Chloë; Viaux, Sylvie; Michelet, Stéphane; Achard, Catherine; Missonnier, Sylvain; Keren, Miri; Cohen, David; Chetouani, Mohamed

    2014-01-01

    Studying early interactions is a core issue of infant development and psychopathology. Automatic social signal processing theoretically offers the possibility to extract and analyze communication by taking an integrative perspective, considering the multimodal nature and dynamics of behaviors (including synchrony). This paper proposes an explorative method to acquire and extract relevant social signals from a naturalistic early parent–infant interaction. An experimental setup is proposed based on both clinical and technical requirements. We extracted various cues from body postures and speech productions of partners using the IMI2S (Interaction, Multimodal Integration, and Social Signal) Framework. Preliminary clinical and computational results are reported for two dyads (one pathological in a situation of severe emotional neglect and one normal control) as an illustration of our cross-disciplinary protocol. The results from both clinical and computational analyzes highlight similar differences: the pathological dyad shows dyssynchronic interaction led by the infant whereas the control dyad shows synchronic interaction and a smooth interactive dialog. The results suggest that the current method might be promising for future studies. PMID:25540633

  2. Social signal processing for studying parent-infant interaction.

    Science.gov (United States)

    Avril, Marie; Leclère, Chloë; Viaux, Sylvie; Michelet, Stéphane; Achard, Catherine; Missonnier, Sylvain; Keren, Miri; Cohen, David; Chetouani, Mohamed

    2014-01-01

    Studying early interactions is a core issue of infant development and psychopathology. Automatic social signal processing theoretically offers the possibility to extract and analyze communication by taking an integrative perspective, considering the multimodal nature and dynamics of behaviors (including synchrony). This paper proposes an explorative method to acquire and extract relevant social signals from a naturalistic early parent-infant interaction. An experimental setup is proposed based on both clinical and technical requirements. We extracted various cues from body postures and speech productions of partners using the IMI2S (Interaction, Multimodal Integration, and Social Signal) Framework. Preliminary clinical and computational results are reported for two dyads (one pathological in a situation of severe emotional neglect and one normal control) as an illustration of our cross-disciplinary protocol. The results from both clinical and computational analyzes highlight similar differences: the pathological dyad shows dyssynchronic interaction led by the infant whereas the control dyad shows synchronic interaction and a smooth interactive dialog. The results suggest that the current method might be promising for future studies.

  3. Child-Robot Interaction Studies: From Lessons Learned to Guidelines

    NARCIS (Netherlands)

    Barco, Alex; Fosch Villaronga, Eduard

    2017-01-01

    This project is about the creation of a set of guidelines for ChildRobot Interaction (CRI) studies in cognitive therapeutic settings. We collected past experiences and lessons learned from previous relevant studies - relating to Traumatic Brain Injury (TBI) and Autism Spectrum Disorder (ASD) – and

  4. Technique of studying the interaction of charges of explosives

    Energy Technology Data Exchange (ETDEWEB)

    Yefremov, E.I.; Kravtsov, V.S.; Myachina, N.I.; Rodak, S.N.

    1982-01-01

    A technique is presented for studying the interaction of explosive charges which includes recording of the velocity of detonation of the studied charges, measurement of mechanical stresses developing in this case in the medium and determination of granulometric composition of the model with simultaneous and diverse initiation.

  5. Types of Interaction in Online Discussion Forums: A Case Study

    Science.gov (United States)

    Khlaif, Zuheir; Nadiruzzaman, Hamid; Kwon, Kyungbin

    2017-01-01

    The purpose of this paper is to identify the types of students' interaction, as well as their discussion patterns in an online course. The study took place in a large Midwestern University and 17 graduate students participated in the study. The primary data was obtained from students' discussion forum postings. The researchers used both…

  6. Continuity in Multi-Device Interaction: An Online Study

    DEFF Research Database (Denmark)

    Raptis, Dimitrios; Kjeldskov, Jesper; Skov, Mikael

    2016-01-01

    Techniques for multi-device interactions are finding their way into commercial products. This means that people are now exposed to possibilities of interacting with and across their devices, and this presents a valuable opportunity for studying their uptake and use in real life. In this paper we...... investigate and discuss the emerging multi-device interaction concept of “continuity”, which allow an activity to begin on one device and continue on another. We present a study of the challenges people have experienced in the use of a specific new product offering such functionality, namely Apple......’s Continuity. The study was done through surveying 3361 posts from technology web sites, discussion forums, and blogs, with a qualitative analysis of 1603 posts. Our findings present challenges in six themes of privacy, appropriation, customization, awareness, exclusion, and troubleshooting in relation...

  7. Study on the Interaction between Two Hydrokinetic Savonius Turbines

    Directory of Open Access Journals (Sweden)

    Kailash Golecha

    2012-01-01

    Full Text Available Savonius turbine is simple in design and easy to fabricate at a lower cost. The drag is the basic driving force for Savonius turbine. Savonius turbines are mainly used for the small-scale electricity generation in remote areas. In real life, multiple Savonius turbines are to be arranged to form a farm to scale up the electricity generation. So, it is important to study the interaction among them to avoid the power loss due to negative interaction between turbines. The purpose of this investigation is to examine closely the effect of interaction between two Savonius turbines arranged in line. Experimental investigations are carried out to study the mutual interaction between turbines with water as the working medium at a Reynolds number of 1.2×105 based on the diameter of the turbine. Influence of separation gap between the two Savonius turbines is studied by varying the separation gap ratio (/ from 3 to 8. As the separation gap ratio increases from 3 to 8, becomes lesser the mutual interaction between the turbines. Results conclude that two turbines placed at a separation gap ratio of 8 performed independently without affecting the performance of each other.

  8. Quantitative studies of antimicrobial peptide-lipid membrane interactions

    DEFF Research Database (Denmark)

    Kristensen, Kasper

    into such novel therapeutics. However, limited understanding of the mechanisms underlying microbicidal activity of antimicrobial peptides has slowed down this development. A central step toward understanding the microbicidal mechanisms of action of antimicrobial peptides is to understand the mechanisms by which......The increasing occurrence of multi-drug-resistant bacteria poses a serious threat to modern society. Therefore, novel types of anti-infective therapeutics are highly warranted. Antimicrobial peptides are a class of naturally occurring host-defense molecules that potentially might be developed...... antimicrobial peptides interact with phospholipid membranes. Motivated by that fact, the scope of this thesis is to study these antimicrobial peptide-lipid membrane interactions. In particular, we attempt to study these interactions with a quantitative approach. For that purpose, we consider the three...

  9. Teachers’ Perception of Interactive White Boards: A Case Study

    Directory of Open Access Journals (Sweden)

    Fatih Saltan

    2013-08-01

    Full Text Available Interactive whiteboards (IWBs are touch-sensitive new generation boards controlled by a computer that is connected to a digital projector (Saltan and Arslan, 2009. In many countries, teachers have begun to use this instructional tool in primary and high schools. In order to investigate teachers’ perceptions and acceptance towards IWBs, this case study was conducted in a primary school in Turkey. 34 teachers from different subject matters participated in the present study. Data were collected through a questionnaire consisting of three parts -- perceived usefulness, perceived ease of use and attitude towards interactive white boards. Descriptive statistic was utilized to analyze the data. Mainly frequencies and percentages were run on the likert-type questions. Results showed that teachers found interactive whiteboard relatively easy to use and useful, in addition they had a positive attitude toward the IWB. However means of the perceived ease of use and attitude toward IWB is lower than perceived usefulness.

  10. Theoretical and Methodological Perspectives on Designing Video Studies of Interaction

    Directory of Open Access Journals (Sweden)

    Anna-Lena Rostvall

    2005-12-01

    Full Text Available In this article the authors discuss the theoretical basis for the methodological decisions made during the course of a Swedish research project on interaction and learning. The purpose is to discuss how different theories are applied at separate levels of the study. The study is structured on three levels, with separate sets of research questions and theoretical concepts. The levels reflect a close-up description, a systematic analysis, and an interpretation of how teachers and students act and interact. The data consist of 12 hours of video-recorded and transcribed music lessons from high school and college. Through a multidisciplinary theoretical framework, the general understanding of teaching and learning in terms of interaction can be widened. The authors also present a software tool developed to facilitate the processes of transcription and analysis of the video data.

  11. Controlled interaction: strategies for using virtual reality to study perception.

    Science.gov (United States)

    Durgin, Frank H; Li, Zhi

    2010-05-01

    Immersive virtual reality systems employing head-mounted displays offer great promise for the investigation of perception and action, but there are well-documented limitations to most virtual reality systems. In the present article, we suggest strategies for studying perception/action interactions that try to depend on both scale-invariant metrics (such as power function exponents) and careful consideration of the requirements of the interactions under investigation. New data concerning the effect of pincushion distortion on the perception of surface orientation are presented, as well as data documenting the perception of dynamic distortions associated with head movements with uncorrected optics. A review of several successful uses of virtual reality to study the interaction of perception and action emphasizes scale-free analysis strategies that can achieve theoretical goals while minimizing assumptions about the accuracy of virtual simulations.

  12. Interaction of magnetic resonators studied by the magnetic field enhancement

    Science.gov (United States)

    Hou, Yumin

    2013-12-01

    It is the first time that the magnetic field enhancement (MFE) is used to study the interaction of magnetic resonators (MRs), which is more sensitive than previous parameters-shift and damping of resonance frequency. To avoid the coherence of lattice and the effect of Bloch wave, the interaction is simulated between two MRs with same primary phase when the distance is changed in the range of several resonance wavelengths, which is also compared with periodic structure. The calculated MFE oscillating and decaying with distance with the period equal to resonance wavelength directly shows the retardation effect. Simulation also shows that the interaction at normal incidence is sensitive to the phase correlation which is related with retardation effect and is ultra-long-distance interaction when the two MRs are strongly localized. When the distance is very short, the amplitude of magnetic resonance is oppressed by the strong interaction and thus the MFE can be much lower than that of single MR. This study provides the design rules of metamaterials for engineering resonant properties of MRs.

  13. Interaction of magnetic resonators studied by the magnetic field enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Yumin, E-mail: ymhou@pku.edu.cn [State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 (China)

    2013-12-15

    It is the first time that the magnetic field enhancement (MFE) is used to study the interaction of magnetic resonators (MRs), which is more sensitive than previous parameters–shift and damping of resonance frequency. To avoid the coherence of lattice and the effect of Bloch wave, the interaction is simulated between two MRs with same primary phase when the distance is changed in the range of several resonance wavelengths, which is also compared with periodic structure. The calculated MFE oscillating and decaying with distance with the period equal to resonance wavelength directly shows the retardation effect. Simulation also shows that the interaction at normal incidence is sensitive to the phase correlation which is related with retardation effect and is ultra-long-distance interaction when the two MRs are strongly localized. When the distance is very short, the amplitude of magnetic resonance is oppressed by the strong interaction and thus the MFE can be much lower than that of single MR. This study provides the design rules of metamaterials for engineering resonant properties of MRs.

  14. Interaction of magnetic resonators studied by the magnetic field enhancement

    Directory of Open Access Journals (Sweden)

    Yumin Hou

    2013-12-01

    Full Text Available It is the first time that the magnetic field enhancement (MFE is used to study the interaction of magnetic resonators (MRs, which is more sensitive than previous parameters–shift and damping of resonance frequency. To avoid the coherence of lattice and the effect of Bloch wave, the interaction is simulated between two MRs with same primary phase when the distance is changed in the range of several resonance wavelengths, which is also compared with periodic structure. The calculated MFE oscillating and decaying with distance with the period equal to resonance wavelength directly shows the retardation effect. Simulation also shows that the interaction at normal incidence is sensitive to the phase correlation which is related with retardation effect and is ultra-long-distance interaction when the two MRs are strongly localized. When the distance is very short, the amplitude of magnetic resonance is oppressed by the strong interaction and thus the MFE can be much lower than that of single MR. This study provides the design rules of metamaterials for engineering resonant properties of MRs.

  15. Non-orthogonal approaches to the study of magnetic interactions

    NARCIS (Netherlands)

    Broer-Braam, H.B.; Hozoi, L; Nieuwpoort, WC

    2003-01-01

    Early theoretical studies of magnetic interactions between paramagnetic centres in solids and molecules are briefly reviewed as an introduction to the main theme of this paper: nonorthogonal CI approaches for the prediction and interpretation of magnetic couplings. In a non-orthogonal CI approach, t

  16. Teaching Interactive Practices and Burnout: A Study on Italian Teachers

    Science.gov (United States)

    Mameli, Consuelo; Molinari, Luisa

    2017-01-01

    The purpose of the present study was to analyse the role played by teaching interactive practices (measured through a self-report Likert scale) in predicting teacher burnout, after controlling for school grade (primary vs. secondary school) and teaching experience. Participants were 282 Italian teachers equally distributed between primary and…

  17. Base flow and exhaust plume interaction. Part 1: Experimental study

    NARCIS (Netherlands)

    Schoones, M.M.J.; Bannink, W.J.

    1998-01-01

    An experimental study of the flow field along an axi-symmetric body with a single operating exhaust nozzle has been performed in the scope of an investigation on base flow-jet plume interactions. The structure of under-expanded jets in a co-flowing supersonic free stream was described using analytic

  18. Cluster variation studies of the anisotropic exchange interaction model

    Science.gov (United States)

    King, T. C.; Chen, H. H.

    The cluster variation method is applied to study critical properties of the Potts-like ferromagnetic anisotropic exchange interaction model. Phase transition temperatures, order parameter discontinuities and latent heats of the model on the triangular and the fcc lattices are determined by the triangle approximation; and those on the square and the sc lattices are determined by the square approximation.

  19. The dynamics of hydrophobic interaction : A microwave dielectric study

    NARCIS (Netherlands)

    Hallenga, Klaas

    1972-01-01

    To investigate the relation between the structure of liquid water and hydrophobic interaction the dielectric relaxation of water in dilute aqueous solutions has been studied. After an introduction of the problem in which the dynamic aspects of water structure are emphasized, a theoretical analysis o

  20. Gene-lifestyle interaction and type 2 diabetes: the EPIC interact case-cohort study.

    Directory of Open Access Journals (Sweden)

    Claudia Langenberg

    2014-05-01

    Full Text Available BACKGROUND: Understanding of the genetic basis of type 2 diabetes (T2D has progressed rapidly, but the interactions between common genetic variants and lifestyle risk factors have not been systematically investigated in studies with adequate statistical power. Therefore, we aimed to quantify the combined effects of genetic and lifestyle factors on risk of T2D in order to inform strategies for prevention. METHODS AND FINDINGS: The InterAct study includes 12,403 incident T2D cases and a representative sub-cohort of 16,154 individuals from a cohort of 340,234 European participants with 3.99 million person-years of follow-up. We studied the combined effects of an additive genetic T2D risk score and modifiable and non-modifiable risk factors using Prentice-weighted Cox regression and random effects meta-analysis methods. The effect of the genetic score was significantly greater in younger individuals (p for interaction  = 1.20×10-4. Relative genetic risk (per standard deviation [4.4 risk alleles] was also larger in participants who were leaner, both in terms of body mass index (p for interaction  = 1.50×10-3 and waist circumference (p for interaction  = 7.49×10-9. Examination of absolute risks by strata showed the importance of obesity for T2D risk. The 10-y cumulative incidence of T2D rose from 0.25% to 0.89% across extreme quartiles of the genetic score in normal weight individuals, compared to 4.22% to 7.99% in obese individuals. We detected no significant interactions between the genetic score and sex, diabetes family history, physical activity, or dietary habits assessed by a Mediterranean diet score. CONCLUSIONS: The relative effect of a T2D genetic risk score is greater in younger and leaner participants. However, this sub-group is at low absolute risk and would not be a logical target for preventive interventions. The high absolute risk associated with obesity at any level of genetic risk highlights the importance of universal

  1. Interaction between atoms and slow light: a design study

    CERN Document Server

    Zang, Xiaorun; Faggiani, Rémi; Gill, Christopher; Petrov, Plamen G; Hugonin, Jean-Paul; Bernon, Simon; Bouyer, Philippe; Boyer, Vincent; Lalanne, Philippe

    2015-01-01

    The emerging field of on-chip integration of nanophotonic devices and cold atoms offers extremely-strong and pure light-matter interaction schemes, which may have profound impact on quantum information science. In this context, a longstanding obstacle is to achieve strong interaction between single atoms and single photons, while at the same time trap atoms in vacuum at large separation distances from dielectric surfaces. In this letter, we study new waveguide geometries that challenge these conflicting objectives. The designed photonic crystal waveguide is expected to offer a good compromise, which additionally allow for easy manipulation of atomic clouds around the structure.

  2. Study of nucleon-nucleon and hyperon-nucleon interaction

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Kiyotaka [Department of Physics, Sophia University, Tokyo (Japan); Takeuchi, Sachiko [Japan College of Social Work, Kiyose (Japan); Buchmann, A.J. [Institute for Theoretical Physics, University of Tuebinge (Germany)

    2000-04-01

    In this paper we review recent investigations of nucleon-nucleon and hyperon-nucleon interactions employing a non-relativistic quark cluster model. We concentrate mainly on the short and medium-range behavior of the baryon-baryon interaction based on the one-gluon and meson exchange potentials. The chiral quark model based on pion and sigma exchange between quarks is also discussed. We also review a study of the deuteron and its electromagnetic properties in a quark model with exchange currents. (author)

  3. Dilatometric, refractometric and viscometric study of lysozyme-cation interaction.

    Science.gov (United States)

    Abad, C; Trueba, M; Campos, A; Figueruelo, J E

    1981-11-01

    The interaction between hen egg-white lysozyme and Cu(II) or Co(II) cations has been studied by dilatometry, equilibrium dialysis-differential refractometry and viscometry at different metal cation concentrations. Delta V isotherms in copper and cobalt solutions have been obtained from dilatometry. Preferential adsorption parameters and specific viscosity have been determined from refractometric and viscosimetric measurements. It has been observed that this interaction produces structural alterations in lysozyme. The magnitude of these conformational changes depends on the metal ion and protein concentration. The results obtained using the three techniques are in good agreement.

  4. Study on the Interaction between Two Hydrokinetic Savonius Turbines

    OpenAIRE

    Kailash Golecha; Eldho, T. I.; S. V. Prabhu

    2012-01-01

    Savonius turbine is simple in design and easy to fabricate at a lower cost. The drag is the basic driving force for Savonius turbine. Savonius turbines are mainly used for the small-scale electricity generation in remote areas. In real life, multiple Savonius turbines are to be arranged to form a farm to scale up the electricity generation. So, it is important to study the interaction among them to avoid the power loss due to negative interaction between turbines. The purpose of this investig...

  5. Spectroscopic studies of the interfacial interactions between polymers and nanostructures

    Science.gov (United States)

    Sampson, William M.

    Optical and vibrational spectroscopies are used to study the interactions of various polymers with several nanoscopic materials. First, two new conjugated polymers manufactured by the Ferraris Group in the Department of Chemistry at The University of Texas at Dallas, poly [1,4-bis-2-ethylhexylmercapto]- p-phenylenevinylene (BEHM-PPV)and poly [1,4-bis-(2-ethylhexyl-sulfinyl)]- p-phenylenevinylene (BEHSO-PPV) are studied along with poly (2,5-bis (2'-ethylhexyloxy)-1,4-p-phenylenevinylene) (BEH-PPV). It is found that the two sulphur containing polymers BEHM-PPV and BEHSO-PPV have a greater tendency to aggregate than does BEH-PPV, and also have bluer photoluminescence. These three polymers are then studied in composite with single walled carbon nanotubes where charge transfer occurs across the interface from the polymer to the nanotubes. These three polymers are studied in mixture with aggregated quantum dots, where it is seen that the quantum dot aggregation prevents significant interactions to occur. The energy transfer interaction between conjugated polymers and transparent, conducting multiwalled carbon nanotubes films is investigated. It is found that a coating of PEDOT-PSS between the nanotubes and conjugated polymer suppresses the quenching of photoluminescence. This effect is important for enhancement of electroluminescence of organic LED devices, in which MWCNT hole injectors are used instead of the usual ITO. The University of Texas developed peptide nano-1 has been shown to engage in charge transfer interactions with SWNTs and, perhaps more importantly, can enable self assembly of complex nanotube structures. Finally, poly [2-methoxy-5-(2'-ethylhexyloxy)- p-phenylenevinylene] (MEH-PPV) and poly[3-hexyl thiophene] (P3HT) are studied in composite with titanium dioxide and an increase in the photoluminescence is seen, induced by interfacial interactions between the polymer and TiO 2. An explanation based on polaron mediated triplet to singlet exciton conversion

  6. Analytical techniques for the study of polyphenol-protein interactions.

    Science.gov (United States)

    Poklar Ulrih, Nataša

    2017-07-03

    This mini review focuses on advances in biophysical techniques to study polyphenol interactions with proteins. Polyphenols have many beneficial pharmacological properties, as a result of which they have been the subject of intensive studies. The most conventional techniques described here can be divided into three groups: (i) methods used for screening (in-situ methods); (ii) methods used to gain insight into the mechanisms of polyphenol-protein interactions; and (iii) methods used to study protein aggregation and precipitation. All of these methods used to study polyphenol-protein interactions are based on modifications to the physicochemical properties of the polyphenols or proteins after binding/complex formation in solution. To date, numerous review articles have been published in the field of polyphenols. This review will give a brief insight in computational methods and biosensors and cell-based methods, spectroscopic methods including fluorescence emission, UV-vis adsorption, circular dichroism, Fourier transform infrared and mass spectrometry, nuclear magnetic resonance, X-ray diffraction, and light scattering techniques including small-angle X-ray scattering and small-angle neutron scattering, and calorimetric techniques (isothermal titration calorimetry and differential scanning calorimetry), microscopy, the techniques which have been successfully used for polyphenol-protein interactions. At the end the new methods based on single molecule detection with high potential to study polyphenol-protein interactions will be presented. The advantages and disadvantages of each technique will be discussed as well as the thermodynamic, kinetic or structural parameters, which can be obtained. The other relevant biophysical experimental techniques that have proven to be valuable, such electrochemical methods, hydrodynamic techniques and chromatographic techniques will not be described here.

  7. A Study of Interaction of Methyl Orange with Some Polycations

    Directory of Open Access Journals (Sweden)

    R. Nandini

    2012-01-01

    Full Text Available The interaction between an anionic dye methyl orange and three poly cations namely, poly (N-methy-4-vinylpyridinium iodide (PM4VPI, poly (vinylbenzyltriphenyl phosphonium chloride (PVBTPPC and poly (N-methy-4-vinylpyridinium iodide (PM2VPI has been investigated by spectrophotometric method. The polymers were observed to induce metachromasy in the dye as evidenced from the considerable blue shift in the absorption maxima of the dye. The interaction constant and thermodynamic parameters of interaction have been determined by absorbance measurements at the metachromatic band. The effect of additives such as ionic salts, alcohols, urea and polyelectrolytes on the reversal of metachromasy has been studied and used to determine the stability of the metachromatic complex and to understand the nature of binding.

  8. Interaction of quercetin with ovalbumin: Spectroscopic and molecular modeling studies

    Energy Technology Data Exchange (ETDEWEB)

    Lu Yan, E-mail: yanlu2001@sohu.co [College of Chemistry and Environmental Science, Henan Normal University, Xinxiang, Henan 453007 (China); Wang Yunlai; Gao Shenghua; Wang Gongke; Yan Changling; Chen Dejun [College of Chemistry and Environmental Science, Henan Normal University, Xinxiang, Henan 453007 (China)

    2009-09-15

    The binding of quercetin (QCT) to ovalbumin (OVA) in aqueous solution was investigated by molecular spectroscopy and modeling at pH 7.4. The fluorescence, synchronous fluorescence and UV-absorption spectroscopies were employed to study the mode and the mechanism for this interaction. QCT binding is characterized by one high affinity binding site with the association constants of the order of 10{sup 5}. The distance between donor (OVA) and acceptor (QCT) was estimated according to Forster's theory of non-radiation energy transfer. Molecular docking showed that the QCT can bind to the active site of OVA. The binding dynamics was expounded by thermodynamic parameters, molecular modeling and accessible surface area calculation, which entails that hydrophobic interactions, hydrogen bonding and electrostatic forces stabilizes the interaction.

  9. CUSTOMER INTERACTION ON DIGITAL ECONOMY: A CASE STUDY

    Directory of Open Access Journals (Sweden)

    Mateus Tavares da Silva Cozer

    2007-10-01

    Full Text Available On a digital economy context, customer interaction is fundamental to any company to provide competitive advantage. This research intends to give concrete answers for the sea of information complexity which is the Internet. The main case is to build a model of digital customer interaction. Customization extends beyond targeted media to include the design and delivery of the product itself. Venkatraman (1998 defines dynamic customization based on three principles: modularity, intelligence and organization. The research is based on Interaction Model and its variables are: Products, Modularity, Artificial Intelligence, Market driven organization, and virtual communities. Two organizations were studied, one with physical product and another with virtual product, and the results were shown from a qualitative research.

  10. Structure, Stability and Interaction Studies on Nucleotide Analogue Systems

    Directory of Open Access Journals (Sweden)

    R. Kanakaraju

    2003-08-01

    Full Text Available Abstract: Most of the biological molecules have a good interaction with water molecules. The hydrogen bonding interactions with the structural analogues of nucleic acid phosphate group namely dimethyl phosphate anion (DMP and diethyl phosphate anion (DEP are studied employing the ab initio and density functional theory methods. Inspections have been made to locate the reactive sites for the interactions of isomeric forms of mono, di and tri hydrates of alkyl phosphate anion using the above theories. It reveals, water molecules have a very strong interaction with the phosphate group in both the molecules and their interactions induce the changes in the structural parameters of the PO4 group for both the DMP and DEP anions. The optimized structural parameters, total energy, dipole moment and rotational constants are calculated and are compared with the available experimental values. The chemical hardness and chemical potential for these complexes have been calculated at HF/6-31G* level of theory and discussed the conformational stability of these complexes.

  11. Groundwater surface water interaction study using natural isotopes tracer

    Science.gov (United States)

    Yoon, Yoon Yeol; Kim, Yong Chul; Cho, Soo Young; Lee, Kil Yong

    2015-04-01

    Tritium and stable isotopes are a component of the water molecule, they are the most conservative tracer for groundwater study. And also, radon is natural radioactive nuclide and well dissolved in groundwater. Therefore, these isotopes are used natural tracer for the study of surface water and groundwater interaction of water curtain greenhouse area. The study area used groundwater as a water curtain for warming tool of greenhouse during the winter, and is associated with issues of groundwater shortage while being subject to groundwater-river water interaction. During the winter time, these interactions were studied by using Rn-222, stable isotopes and H-3. These interaction was monitored in multi depth well and linear direction well of groundwater flow. And dam effect was also compared. Samples were collected monthly from October 2013 to April 2014. Radon and tritium were analyzed using Quantulus low background liquid scintillation counter and stable isotopes were analyzed using an IRIS (Isotope Ratio Infrared Spectroscopy ; L2120-i, Picarro). During the winter time, radon concentration was varied from 0.07 Bq/L to 8.9 Bq/L and different interaction was showed between dam. Surface water intrusion was severe at February and restored April when greenhouse warming was ended. The stable isotope results showed different trend with depth and ranged from -9.16 ‰ to -7.24 ‰ for δ 18O value, while the δD value was ranged from -57.86 ‰ to -50.98 ‰. The groundwater age as dated by H-3 was ranged 0.23 Bq/L - 0.59 Bq/L with an average value of 0.37 Bq/L.

  12. Alcohol-related breast cancer in postmenopausal women - effect of CYP19A1, PPARG and PPARGC1A polymorphisms on female sex-hormone levels and interaction with alcohol consumption and NSAID usage in a nested case-control study and a randomised controlled trial

    DEFF Research Database (Denmark)

    Kopp, Tine Iskov; Jensen, Ditte Marie; Ravn-Haren, Gitte;

    2016-01-01

    19A1 is associated with risk of BC in a case-control study group nested within the Danish "Diet, Cancer and Health" cohort (ncases = 687 and ncontrols = 687) and searched for gene-gene interaction between CYP19A1 and PPARGC1A, and CYP19A1 and PPARG, and gene-alcohol and gene-NSAID interactions....... Association between the CYP19A1 polymorphisms and hormone levels was also examined among 339 non-HRT users. Incidence rate ratios were calculated based on Cox' proportional hazards model. Furthermore, we performed a pilot randomised controlled trial to determine the effect of the PPARG Pro(12)Ala polymorphism......Alcohol consumption is associated with increased risk of breast cancer (BC), and the underlying mechanism is thought to be sex-hormone driven. In vitro and observational studies suggest a mechanism involving peroxisome proliferator-activated receptor gamma (PPARγ) in a complex with peroxisome...

  13. Crack Interactions Study Under Thermal Load Using EFGM and XFEM

    Directory of Open Access Journals (Sweden)

    Himanshu Pathak

    2012-06-01

    Full Text Available Multiple voids exists in all engineering component which interact with each other and affects the stress intensity factor. During their service life engineering component exposed to thermal loading. The thermal loading creates the singular stress field at the crack tip, which causes the sudden failure of component and loss of human life. Thus, the study of crack interactions under thermal loading is of great importance. In the present work, crack interaction study has been performed under mixed mode thermal loading using element free Galerkin method (EFGM and extended finite element method (XFEM. In EFGM and XFEM, the domain of interest is discretized by scattered nodes and standard FEM element respectively without physically having any crack in the domain, and the presence of a crack in the domain is ensured by extrinsic enrichment only. In extrinsic enrichment technique, additional functions were added with the standard displacement based approximation within partition of unity (PU framework. These additional functions were taken from the theoretical background of the problem. The model problems including edge crack and edge crack interactions under thermal loading solved by both EFGM and XFEM.

  14. Tacrine derivatives-acetylcholinesterase interaction: 1H NMR relaxation study.

    Science.gov (United States)

    Delfini, Maurizio; Di Cocco, Maria Enrica; Piccioni, Fabiana; Porcelli, Fernando; Borioni, Anna; Rodomonte, Andrea; Del Giudice, Maria Rosaria

    2007-06-01

    Two acetylcholinesterase (AChE) inhibitors structurally related to Tacrine, 6-methoxytacrine (1a) and 9-heptylamino-6-methoxytacrine (1b), and their interaction with Electrophorus Electricus AChE were investigated. The complete assignment of the 1H and 13C NMR spectra of 1a and 1b was performed by mono-dimensional and homo- and hetero-correlated two-dimensional NMR experiments. This study was undertaken to elucidate the interaction modes between AChE and 1a and 1b in solution, using NMR. The interaction between the two inhibitors and AChE was studied by the analysis of the motional parameters non-selective and selective spin-lattice relaxation times, thereby allowing the motional state of 1a and 1b, both free and bound with AChE, to be defined. The relaxation data pointed out the ligands molecular moiety most involved in the binding with AChE. The relevant ligand/enzyme interaction constants were also evaluated for both compounds and resulted to be 859 and 5412M(-1) for 1a and1b, respectively.

  15. A Review of Ocean-Atmosphere Interaction Studies in China

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A large number of papers have been published and great efforts have been made in the recent 20 years by the Chinese oceanographic and meteorological scientists in the ocean-atmosphere interaction studies. The present paper is an overview of the major achievements made by Chinese scientists and their collaborators in studies of larger scale ocean-atmosphere interaction in the following oceans: the South China Sea, the Tropical Pacific, the Indian Ocean and the North Pacific. Many interesting phenomena and dynamic mechanisms have been discovered and studied in these papers. These achievements have improved our understanding of climate variability and have great implications in climate prediction, and thus are highly relevant to the ongoing international Climate Variability and Predictability (CLIVAR)efforts.

  16. Molecular interaction studies of hemostasis: fibrinogen ligand-human platelet receptor interactions

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Imshik; Marchant, Roger E

    2003-10-15

    The interactions between fibrinogen ligands and platelet receptor {alpha}{sub IIb}{beta}{sub 3} were studied under physiological conditions by atomic force microscopy (AFM). Two linear peptide sequences in fibrinogen, RGD and HHLGGAKQAGDV, play central roles in the regulation of hemostasis and thrombosis by facilitating adhesion and aggregation of platelets. In order to measure the interactions (i.e., debonding force), oligopeptides, GSSSGaaa, where aaa is -RGDSPA or -HHLGGAKQAGDV, were synthesized and grafted on to the surface of AFM probe tips. The interaction forces between a peptide-modified AFM probe tip and platelet surface were determined from pN to nN levels using AFM force measurements. Our results show that the zero kinetic off-rate, K{sub off}(0), for RGDSPA is significantly smaller than that for HHLGGAKQAGDV, under the consideration of flexible receptor surfaces. From our analysis, the K{sub off}(0), the single molecular binding energy E{sub b}, and the transition state x{sub b}, were extracted from the data, and estimated to be 1.53 s{sup -1}, -2.64x10{sup -20} J and 1.03 A for the RGD-{alpha}{sub IIb}{beta}{sub 3} system, and 47.58 s{sup -1}, 2.67x10{sup -20}, 1.09 A for the HHLGGAKQAGDV-{alpha}{sub IIb}{beta}{sub 3} system, respectively.

  17. Cellular studies and interaction mechanisms of extremely low frequency fields

    Science.gov (United States)

    Liburdy, Robert P.

    1995-01-01

    Worldwide interest in the biological effects of ELF (extremely low frequency, electromagnetic fields has grown significantly. Health professionals and government administrators and regulators, scientists and engineers, and, importantly, an increasing number of individuals in the general public are interested in this health issue. The goal of research at the cellular level is to identify cellular responses to ELF fields, to develop a dose threshold for such interactions, and with such information to formulate and test appropriate interaction mechanisms. This review is selective and will discuss the most recent cellular studies directed at these goals which relate to power line, sinusoidal ELF fields. In these studies an interaction site at the cell membrane is by consensus a likely candidate, since changes in ion transport, ligand-receptor events such as antibody binding, and G protein activation have been reported. These changes strongly indicate that signal transduction (ST) can be influenced. Also, ELF fields are reported to influence enzyme activation, gene expression, protein synthesis, and cell proliferation, which are triggered by earlier ST events at the cell membrane. The concept of ELF fields altering early cell membrane events and thereby influencing intracellular cell function via the ST cascade is perhaps the most plausible biological framework currently being investigated for understanding ELF effects on cells. For example, the consequence of an increase due to ELF fields in mitogenesis, the final endpoint of the ST cascade, is an overall increase in the probability of mutagenesis and consequently cancer, according to the Ames epigenetic model of carcinogenesis. Consistent with this epigenetic mechanism and the ST pathway to carcinogenesis is recent evidence that ELF fields can alter breast cancer cell proliferation and can act as a copromoter in vitro. The most important dosimetric question being addressed currently is whether the electric (E) or the

  18. Studies of interaction between two alkaloids and double helix DNA

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yantao [Key Laboratory of Preparation and Applications of Environmentally Friendly Materials (Jilin Normal University), Ministry of Education China, Siping 136000 (China); College of Chemistry, Jilin Normal University, Siping 136000 (China); Peng, Tingting [College of Chemistry, Jilin Normal University, Siping 136000 (China); College of Chemistry, Baicheng Normal University, Baicheng, 130032 (China); Zhao, Lei [Siping Institute for Food and Drug Control, Siping 136000 (China); Jiang, Dayu [Key Laboratory of Preparation and Applications of Environmentally Friendly Materials (Jilin Normal University), Ministry of Education China, Siping 136000 (China); College of Chemistry, Jilin Normal University, Siping 136000 (China); Cui, Yuncheng, E-mail: 1979yanzi@163.com [Key Laboratory of Preparation and Applications of Environmentally Friendly Materials (Jilin Normal University), Ministry of Education China, Siping 136000 (China); College of Chemistry, Jilin Normal University, Siping 136000 (China)

    2014-12-15

    This article presents the study on the interaction of two alkaloids (matrine and evodiamine) and hs-DNA by absorption, fluorescence, circular dichroism (CD), DNA melting and viscosity experiments. The spectroscopic studies suggested that two alkaloids can bind to DNA through an intercalative mode. The viscosity measurement and thermal denaturation also indicated that two alkaloids can intercalate to DNA. The binding constants (K{sub A}) and the number of binding sites (n) were determined. At the same time, some significant thermodynamic parameters of the binding of the alkaloids to DNA were obtained. Competitive binding studies revealed that alkaloids had an effect on ethidium bromide (EB) bound DNA. In addition, it was also proved that the fluorescence quenching was influenced by ionic strength. - Highlights: • Interaction between two alkaloids and DNA is studied by spectral methods. • The binding constant and the binding sites between two alkaloids and DNA are obtained. • There are a classical intercalative mode between alkaloids and DNA. • The binding of matrine with DNA is weaker than that of evodiamine. • It is important for us to understand the alkaloids–DNA interactions at a molecular level.

  19. Twenty years of protein interaction studies for biological function deciphering.

    Science.gov (United States)

    Legrain, Pierre; Rain, Jean-Christophe

    2014-07-31

    Intensive methodological developments and technology innovation have been devoted to protein-protein interaction studies over 20years. Genetic indirect assays and sophisticated large scale biochemical analyses have jointly contributed to the elucidation of protein-protein interactions, still with a lot of drawbacks despite heavy investment in human resources and technologies. With the most recent developments in mass spectrometry and computational tools for studying protein content of complex samples, the initial goal of deciphering molecular bases of biological functions is now within reach. Here, we described the various steps of this process and gave examples of key milestones in this scientific story line. This article is part of a Special Issue entitled: 20years of Proteomics in memory of Viatliano Pallini. Guest Editors: Luca Bini, Juan J. Calvete, Natacha Turck, Denis Hochstrasser and Jean-Charles Sanchez.

  20. A Numerical Study on Hydrodynamic Interactions between Dynamic Positioning Thrusters

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Doo Hwa; Lee, Sang Wook [University of Ulsan, Ulsan (Korea, Republic of)

    2017-06-15

    In this study, we conducted computational fluid dynamics (CFD) simulations for the unsteady hydrodynamic interaction of multiple thrusters by solving Reynolds averaged Navier-Stokes equations. A commercial CFD software, STAR-CCM+ was used for all simulations by employing a ducted thruster model with combination of a propeller and No. 19a duct. A sliding mesh technique was used to treat dynamic motion of propeller rotation and non-conformal hexahedral grid system was considered. Four different combinations in tilting and azimuth angles of the thrusters were considered to investigate the effects on the propulsion performance. We could find that thruster-hull and thruster-thruster interactions has significant effect on propulsion performance and further study will be required for the optimal configurations with the best tilting and relative azimuth angle between thrusters.

  1. Interactive verification of Markov chains: Two distributed protocol case studies

    Directory of Open Access Journals (Sweden)

    Johannes Hölzl

    2012-12-01

    Full Text Available Probabilistic model checkers like PRISM only check probabilistic systems of a fixed size. To guarantee the desired properties for an arbitrary size, mathematical analysis is necessary. We show for two case studies how this can be done in the interactive proof assistant Isabelle/HOL. The first case study is a detailed description of how we verified properties of the ZeroConf protocol, a decentral address allocation protocol. The second case study shows the more involved verification of anonymity properties of the Crowds protocol, an anonymizing protocol.

  2. Computational Study of Colloidal Droplet Interactions with Three Dimensional Structures

    Science.gov (United States)

    2015-05-18

    interaction between the nanoparticle and the solid matrix is modeled using a particle trajectory method. Using the multi- scale modeling approach, a... parametric study was conducted to investigate the effects of the droplet impact speed, the fluid viscosity, and the permeability of the porous matrix on...undergraduates who achieved a 3.5 GPA to 4.0 (4.0 max scale ): Number of graduating undergraduates funded by a DoD funded Center of Excellence grant for Education

  3. Optical methods in the study of protein-protein interactions.

    Science.gov (United States)

    Masi, Alessio; Cicchi, Riccardo; Carloni, Adolfo; Pavone, Francesco Saverio; Arcangeli, Annarosa

    2010-01-01

    Förster (or Fluorescence) resonance energy transfer (FRET) is a physical process in which energy is transferred nonradiatively from an excited fluorophore, serving as a donor, to another chromophore (acceptor). Among the techniques related to fluorescence microscopy, FRET is unique in providing signals sensitive to intra- and intermolecular distances in the 1-10 nm range. Because of its potency, FRET is increasingly used to visualize and quantify the dynamics of protein-protein interaction in living cells, with high spatio-temporal resolution. Here we describe the physical bases of FRET, detailing the principal methods applied: (1) measurement of signal intensity and (2) analysis of fluorescence lifetime (FLIM). Although several technical complications must be carefully considered, both methods can be applied fruitfully to specific fields. For example, FRET based on intensity detection is more suitable to follow biological phenomena at a finely tuned spatial and temporal scale. Furthermore, a specific fluorescence signal occurring close to the plasma membrane (advantage of the discovery and use of spontaneously fluorescent proteins, like the green fluorescent protein (GFP). Until now, FRET has been widely used to analyze the structural characteristics of several proteins, including integrins and ion channels. More recently, this method has been applied to clarify the interaction dynamics of these classes of membrane proteins with cytosolic signaling proteins. We report two examples in which the interaction dynamics between integrins and ion channels have been studied with FRET methods. Using fluorescent antibodies and applying FRET-FLIM, the direct interaction of beta1 integrin with the receptor for Epidermal Growth Factor (EGF-R) has been proved in living endothelial cells. A different approach, based on TIRFM measurement of the FRET intensity of fluorescently labeled recombinant proteins, suggests that a direct interaction also occurs between integrins and the

  4. INTERACT

    DEFF Research Database (Denmark)

    Jochum, Elizabeth; Borggreen, Gunhild; Murphey, TD

    This paper considers the impact of visual art and performance on robotics and human-computer interaction and outlines a research project that combines puppetry and live performance with robotics. Kinesics—communication through movement—is the foundation of many theatre and performance traditions...... interaction between a human operator and an artificial actor or agent. We can apply insights from puppetry to develop culturally-aware robots. Here we describe the development of a robotic marionette theatre wherein robotic controllers assume the role of human puppeteers. The system has been built, tested...

  5. Alecto 2 - interaction studies; Alecto 2 - etudes d'interaction

    Energy Technology Data Exchange (ETDEWEB)

    Brunet, J.P.; Clouet d' Orval, Ch.; Mougniot, J.C.; Penet, F. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    Weak interactions were experimentally studies with the tank of the critical assembly Alecto II and one, two or three bottles containing solutions of various concentrations. In particular, was studied the validity of certain classical assumptions, shielding effects, screening and semi-reflexion effects, importance of thermal coupling. The method of the 'k{sub eff}, solid angle' is shown to apply to such a system. The determination by divergence and pulsed neutron technique of the reactivity related to a millimeter of solution level affords the obtention of critical heights in terms of reactivity. (authors) [French] Une etude experimentale d'interactions faibles a ete faite entre la cuve de l'experience critique ALECTO II et une, deux ou trois bouteilles contenant des concentrations variees. On etudie, en particulier, la validite de certaines hypotheses classiques, effets d'ombre, d'ecrans, de semi-reflexion, importance du couplage thermique. On montre d'autre part que la methode du 'K{sub eff}, angle solide' peut s'appliquer a un tel systeme. La determination par divergence et neutrons pulses de la reactivite liee au millimetre de solution permet de traduire les hauteurs critiques obtenues, en terme de reactivite. (auteurs)

  6. Nanoparticle-lipid bilayer interactions studied with lipid bilayer arrays

    Science.gov (United States)

    Lu, Bin; Smith, Tyler; Schmidt, Jacob J.

    2015-04-01

    The widespread environmental presence and commercial use of nanoparticles have raised significant health concerns as a result of many in vitro and in vivo assays indicating toxicity of a wide range of nanoparticle species. Many of these assays have identified the ability of nanoparticles to damage cell membranes. These interactions can be studied in detail using artificial lipid bilayers, which can provide insight into the nature of the particle-membrane interaction through variation of membrane and solution properties not possible with cell-based assays. However, the scope of these studies can be limited because of the low throughput characteristic of lipid bilayer platforms. We have recently described an easy to use, parallel lipid bilayer platform which we have used to electrically investigate the activity of 60 nm diameter amine and carboxyl modified polystyrene nanoparticles (NH2-NP and COOH-NP) with over 1000 lipid bilayers while varying lipid composition, bilayer charge, ionic strength, pH, voltage, serum, particle concentration, and particle charge. Our results confirm recent studies finding activity of NH2-NP but not COOH-NP. Detailed analysis shows that NH2-NP formed pores 0.3-2.3 nm in radius, dependent on bilayer and solution composition. These interactions appear to be electrostatic, as they are regulated by NH2-NP surface charge, solution ionic strength, and bilayer charge. The ability to rapidly measure a large number of nanoparticle and membrane parameters indicates strong potential of this bilayer array platform for additional nanoparticle bilayer studies.The widespread environmental presence and commercial use of nanoparticles have raised significant health concerns as a result of many in vitro and in vivo assays indicating toxicity of a wide range of nanoparticle species. Many of these assays have identified the ability of nanoparticles to damage cell membranes. These interactions can be studied in detail using artificial lipid bilayers, which

  7. A numerical parametric study on hydrofoil interaction in tandem

    Science.gov (United States)

    Kemal, Omer

    2015-01-01

    Understanding the effects of the parameters affecting the interaction of tandem hydrofoil system is a crucial subject in order to fully comprehend the aero/hydrodynamics of any vehicle moving inside a fluid. This study covers a parametric study on tandem hydrofoil interaction in both potential and viscous fluids using iterative Boundary Element Method (BEM) and RANSE. BEM allows a quick estimation of the flow around bodies and may be used for practical purposes to assess the interaction inside the fluid. The produced results are verified by conformal mapping and Finite Volume Method (FVM). RANSE is used for viscous flow conditions to assess the effects of viscosity compared to the inviscid solutions proposed by BEM. Six different parameters are investigated and they are the effects of distance, thickness, angle of attack, chord length, aspect ratio and tapered wings. A generalized 2-D code is developed implementing the iterative procedure and is adapted to generate results. Effects of free surface and cavitation are ignored. It is believed that the present work will provide insight into the parametric interference between hydrofoils inside the fluid

  8. A numerical parametric study on hydrofoil interaction in tandem

    Directory of Open Access Journals (Sweden)

    Kemal Omer

    2015-01-01

    Full Text Available Understanding the effects of the parameters affecting the interaction of tandem hydrofoil system is a crucial subject in order to fully comprehend the aero/hydrodynamics of any vehicle moving inside a fluid. This study covers a parametric study on tandem hydrofoil interaction in both potential and viscous fluids using iterative Boundary Element Method (BEM and RANSE. BEM allows a quick estimation of the flow around bodies and may be used for practical purposes to assess the interaction inside the fluid. The produced results are verified by conformal mapping and Finite Volume Method (FVM. RANSE is used for viscous flow conditions to assess the effects of viscosity compared to the inviscid solutions proposed by BEM. Six different parameters are investigated and they are the effects of distance, thickness, angle of attack, chord length, aspect ratio and tapered wings. A generalized 2-D code is developed implementing the iterative procedure and is adapted to generate results. Effects of free surface and cavitation are ignored. It is believed that the present work will provide insight into the parametric interference between hydrofoils inside the fluid

  9. A numerical parametric study on hydrofoil interaction in tandem

    Directory of Open Access Journals (Sweden)

    Omer Kemal Kinaci

    2015-01-01

    Full Text Available Understanding the effects of the parameters affecting the interaction of tandem hydrofoil system is a crucial subject in order to fully comprehend the aero/hydrodynamics of any vehicle moving inside a fluid. This study covers a parametric study on tandem hydrofoil interaction in both potential and viscous fluids using iterative Boundary Element Method (BEM and RANSE. BEM allows a quick estimation of the flow around bodies and may be used for practical purposes to assess the interaction inside the fluid. The produced results are verified by conformal mapping and Finite Volume Method (FVM. RANSE is used for viscous flow conditions to assess the effects of viscosity compared to the inviscid solutions proposed by BEM. Six different parameters are investigated and they are the effects of distance, thickness, angle of attack, chord length, aspect ratio and tapered wings. A generalized 2-D code is developed implementing the iterative procedure and is adapted to generate results. Effects of free surface and cavitation are ignored. It is believed that the present work will provide insight into the parametric interference between hydrofoils inside the fluid.

  10. Water-clay surface interaction: A neutron scattering study

    Energy Technology Data Exchange (ETDEWEB)

    Sobolev, O., E-mail: sobolev38@gmail.com [LGIT, University of Grenoble and CNRS, BP 53-38041 Grenoble (France); Favre Buivin, F. [HES-SO Fribourg, Bd de Perolles 80-CP 32, CH-1705 Fribourg (Switzerland); Kemner, E.; Russina, M. [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Glienicker Strasse 100, D-14109 Berlin (Germany); Beuneu, B. [Laboratoire Leon Brillouin, C.E. Saclay, 91191 Gif sur Yvette (France); Cuello, G.J. [Institut Laue Langevin and Ikerbasque, 6, rue Jules Horowitz, BP 156, 38042 Grenoble, Cedex 9 (France); Charlet, L. [LGIT, University of Grenoble and CNRS, BP 53-38041 Grenoble (France)

    2010-08-23

    Graphical abstract: Interaction between water molecules and internal clay surfaces was studied by means of neutron diffraction and quasielastic neutron scattering. A hydrophobic cation, TMA{sup +} was used to reduce hydration of interlayer cations. - Abstract: The aim of this study was to investigate interaction between water molecules and internal clay surfaces by means of neutron diffraction and quasielastic neutron scattering. A hydrophobic cation, TMA{sup +} (NC{sub 4}H{sub 12}), was used to saturate the interlayer space of nontronite NAu-1 in order to reduce hydration of interlayer cations that could hinder the effects related to the clay-water interactions. The water content was low in order to reduce hydrogen bonding between water molecules. It was found that water molecules form strong hydrogen bonds with surface oxygen atoms of nontronite. The diffusion activation energy value E{sub a} = 29 {+-} 3 kJ/mol was obtained for water molecules hydrating the clay surface. These results confirm the assumption that surfaces of smectite clays with tetrahedral substitutions are hydrophilic.

  11. Spectroscopic studies on the interaction of bilirubin with liver cystatin.

    Science.gov (United States)

    Shah, Aaliya; Bano, Bilqees

    2011-02-01

    Studies on the role of endogenous metabolites such as bilirubin and their interactions with biomolecules have attracted considerable attention over the past several years. In this work, the interaction of bilirubin (BR) with purified goat liver cystatin (LC) was studied using fluorescence and ultraviolet (UV) spectroscopy. The fluorescence data proved that the fluorescence quenching of liver cystatin by BR was the result of BR-cystatin complex formation. Stern-Volmer analysis of fluorescence quenching data showed the binding constant to be 9.27 x 10⁴ M⁻¹ and the number of binding sites to be close to unity. The conformation of the BR-cystatin complex was found to change upon varying the pH of the complex. The BR-cystatin complex was found to have reduced papain inhibitory activity. Photo-illumination of BR-cystatin complex causes perturbation in the micro-environment of goat liver cystatin as indicated by red-shift. This report summarizes our research efforts to reveal the mechanism of interaction of bilirubin with liver cystatin.

  12. New Systems for Studying Intercellular Interactions in Bacterial Vaginosis

    Science.gov (United States)

    Herbst-Kralovetz, Melissa M.; Pyles, Richard B.; Ratner, Adam J.; Sycuro, Laura K.; Mitchell, Caroline

    2016-01-01

    Bacterial vaginosis (BV) affects almost a quarter of US women, making it a condition of major public health relevance. Key questions remain regarding the etiology of BV, mechanisms for its association with poor reproductive health outcomes, and reasons for high rates of treatment failure. New model systems are required to answer these remaining questions, elucidate the complex host-microbe and microbe-microbe interactions, and develop new, effective interventions. In this review, we cover the strengths and limitations of in vitro and in vivo model systems to study these complex intercellular interactions. Furthermore, we discuss advancements needed to maximize the translational utility of the model systems. As no single model can recapitulate all of the complex physiological and environmental conditions of the human vaginal microenvironment, we conclude that combinatorial approaches using in vitro and in vivo model systems will be required to address the remaining fundamental questions surrounding the enigma that is BV. PMID:27449872

  13. Polymers' surface interactions with molten iron: A theoretical study

    Science.gov (United States)

    Assadi, M. Hussein N.; Sahajwalla, Veena

    2014-10-01

    Environmental concerns are the chief drive for more innovative recycling techniques for end-of-life polymeric products. One attractive option is taking advantage of C and H content of polymeric waste in steelmaking industry. In this work, we examined the interaction of two high production polymers i.e. polyurethane and polysulfide with molten iron using ab initio molecular dynamics simulation. We demonstrate that both polymers can be used as carburizers for molten iron. Additionally, we found that light weight H2 and CHx molecules were released as by-products of the polymer-molten iron interaction. The outcomes of this study will have applications in the carburization of molten iron during ladle metallurgy and waste plastic injection in electric arc furnace.

  14. Studies on molecular interactions between puerarin and PC liposomes

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Fluorescence emission spectra, FTIR spectra, zeta potential measurements, and ab initio quantum calculation are used to study the interaction between puerarin and membranes composed of egg phosphatidylcholine (PC) liposome. The hydrophobic interactions cause the puerarin molecule to partition into lipid bilayers with its B-ring, and favor the displacement of acid-base equilibrium of puerarin towards the base form. Due to the hydrogen bond formation between the puerarin hydroxyl groups and polar groups of PC molecules on the water/membrane interface, puerarin can easily intercalate into the organized structure of phospholipids and modulate the membrane function. Our results reveal that the liposome membrane integrity is significantly higher compared with that of empty liposome.

  15. Study of the Interaction of Fluxes of Annihilating Particles

    Science.gov (United States)

    Nazarov, A. A.; Feropontova, N. M.

    2015-12-01

    A study of interacting particle fluxes in the form of an infinite linear queueing system with positive and negative requests is presented for different types of such systems. For the first class of systems with exponential service a stationary probability distribution of the number of positive requests in the system has been found. For the second class of systems, for the case of arbitrary service, the study is performed by the method of asymptotic analysis. Asymptotic equivalence of the systems under consideration is demonstrated.

  16. Discourse and Interaction Studies in the ‘New North’

    DEFF Research Database (Denmark)

    McIlvenny, Paul

    The plenary roundtable draws together key scholars from the Nordic countries and scholars living in the Nordic region to discuss the future of discourse and interaction studies in the Nordic region. It will address what sorts of approaches in discourse studies do we need for studying and shaping...... 'the Nordic' in the twenty first century, and what theoretical concepts and methodological principles should we abide by or develop. For example, the roundtable could discuss the theme of challenges to 'the Nordic model'. How are the North's so-called social welfare and healthcare model and its...... understandings of itself as a community of peaceful, caring societies built on consensus social democracy challenged by neoliberalism, globalisation and immigration? How can discourse studies study these developments in a positive yet critical fashion, with tools crafted with our concerns (not Anglo American...

  17. Interaction in the English classroom; an exploratory study

    Directory of Open Access Journals (Sweden)

    Fernández Abarca, Marianella

    2004-06-01

    Full Text Available El objetivo de este artículo es describir el tipo de interacción que ocurrió en una clase de Inglés en un colegio p��blico de zona rural en Costa Rica. Se presentan algunos principios teóricos relacionados con la interacción en la clase de idioma. Se utilizó el método etnográfico del paradigma cualitativo para llevar a cabo este estudio. Entre las técnicas e instrumentos utilizados están la observación no participante, el uso de un cuestionario, entrevistas, y diarios personales. Se utilizó la triangulación para validar las interpretaciones, recomendaciones, y los resultados de este estudio. Se concluye que la interacción entre profesor-estudiante y estudiante-estudiante está basada en un modelo de pregunta-respuesta en donde el profesor regula y limita la participación de los estudiantes mediante el uso de diferentes activities las cuales no estimulan un aprendizaje significativo. Los estudiantes están motivados en aprender Inglés, sin embargo existen pocos espacios para interactuar. La participación de los estudiantes es pasiva y limitada, la mayor parte del tiempo escuchan, repiten, preguntan, y responden. Los estudiantes utilizan el idioma Español para comunicarse e interactuar entre ellos. El estudio sugiere variar las actividades que se llevan a cabo en la clase para mejorar el aprendizaje de los estudiantes. The main purpose of this article is to describe the interaction process that took place in an English as a Foreign Language (EFL classroom at a public high school in the province of Alajuela, Costa Rica. This article examines some theoretical background knowledge in regards to the interaction in the language classroom. The ethnographic method, which belongs to the qualitative paradigm, was used to conduct this study. Some of the techniques and the instruments used were the non-participant observations, the use of a questionnaire, interviews, and personal diaries. Triangulation was applied in order to make

  18. Study of interaction in silica glass via model potential approach

    Science.gov (United States)

    Mann, Sarita; Rani, Pooja

    2016-05-01

    Silica is one of the most commonly encountered substances in daily life and in electronics industry. Crystalline SiO2 (in several forms: quartz, cristobalite, tridymite) is an important constituent of many minerals and gemstones, both in pure form and mixed with related oxides. Cohesive energy of amorphous SiO2 has been investigated via intermolecular potentials i.e weak Van der Waals interaction and Morse type short-range interaction. We suggest a simple atom-atom based Van der Waals as well as Morse potential to find cohesive energy of glass. It has been found that the study of silica structure using two different model potentials is significantly different. Van der Waals potential is too weak (P.E =0.142eV/molecule) to describe the interaction between silica molecules. Morse potential is a strong potential, earlier given for intramolecular bonding, but if applied for intermolecular bonding, it gives a value of P.E (=-21.92eV/molecule) to appropriately describe the structure of silica.

  19. Ecological interaction and phylogeny, studying functionality on composed networks

    Science.gov (United States)

    Cruz, Claudia P. T.; Fonseca, Carlos Roberto; Corso, Gilberto

    2012-02-01

    We study a class of composed networks that are formed by two tree networks, TP and TA, whose end points touch each other through a bipartite network BPA. We explore this network using a functional approach. We are interested in how much the topology, or the structure, of TX (X=A or P) determines the links of BPA. This composed structure is a useful model in evolutionary biology, where TP and TA are the phylogenetic trees of plants and animals that interact in an ecological community. We make use of ecological networks of dispersion of fruits, which are formed by frugivorous animals and plants with fruits; the animals, usually birds, eat fruits and disperse their seeds. We analyse how the phylogeny of TX determines or is correlated with BPA using a Monte Carlo approach. We use the phylogenetic distance among elements that interact with a given species to construct an index κ that quantifies the influence of TX over BPA. The algorithm is based on the assumption that interaction matrices that follows a phylogeny of TX have a total phylogenetic distance smaller than the average distance of an ensemble of Monte Carlo realisations. We find that the effect of phylogeny of animal species is more pronounced in the ecological matrix than plant phylogeny.

  20. Use of interactive lecture demonstrations: A ten year study

    Directory of Open Access Journals (Sweden)

    Ronald Thornton

    2010-10-01

    Full Text Available The widely held constructivist view of learning advocates student engagement via interactivity. Within the physics education research community, several specific interactive strategies have been developed to enhance conceptual understanding. One such strategy, the Interactive Lecture Demonstration (ILD is designed for large lecture classes and, if measured using specific conceptual surveys, is purported to provide learning gains of up to 80%. This paper reports on learning gains for two different Projects over ten years. In Project 1, the ILDs were implemented from 1999 to 2001 with students who had successfully completed senior high school physics. The learning gains for students not exposed to the ILDs were in the range 13% to 16% while those for students exposed to the ILDs was 31% to 50%. In Project 2, the ILDs were implemented from 2007 to 2009 with students who had not studied senior high school physics. Since the use of ILDs in Project 1 had produced positive results, ethical considerations dictated that all students be exposed to ILDs. The learning gains were from 28% to 42%. On the one hand it is pleasing to note that there is an increase in learning gains, yet on the other, we note that the gains are nowhere near the claimed 80%. This paper also reports on teacher experiences of using the ILDs, in Project 2.

  1. In vivo andin vitro interaction studies of ibuprofen with enalapril

    Institute of Scientific and Technical Information of China (English)

    Safila Naveed; Najma Sultana; Muhammad Saeed Arayne

    2016-01-01

    Objective: To study thein vitro interactions of ibuprofen with enalapril. Methods: In this study, we investigated synergistic effect of angiotensin-converting enzyme inhibitor (enalapril) with commonly used nonsteroidal anti-inflammatory drug, ibuprofen in carrageenan induced inflammation rats. Anti-inflammatory response was observed for ibuprofen when given simultaneously with enalapril by comparing decrease in paw size. Results: The results were expressed in percentage reduction in paw size for every hour and were calculated for edema rate and percentage reduction in inflammation.In vitro interaction studies were carried out using high performance liquid chromatography and both the drugs were analyzed by assaying both drugs alone and in combination. The combination of enalapril and ibuprofen showed increased action of ibuprofen as shown by the increase of percentage reduction and decrease in edema rate. It was also proved from analytical ultracentrifugation of the chromatogram of combining drugs. Conclusions: This learning has certain restriction as a number of experienced animals were small and the period of inflammatory response was checked for ibuprofen alone and simultaneous with enalapril for 5 h. Further studies may be required to establish the strong relationship.

  2. Acquiring Interactional Competence in a Study Abroad Context: Japanese Language Learners' Use of the Interactional Particle "ne"

    Science.gov (United States)

    Masuda, Kyoko

    2011-01-01

    This study examines the development of interactional competence (Hall, 1993, 1995) by English-speaking learners of Japanese as a foreign language (JFL) in a study abroad setting, as indexed by their use of the interactionally significant particle "ne." The analysis is based on a comparison of (a) 6 sets of conversations between JFL learners and…

  3. A validation study of a stochastic model of human interaction

    Science.gov (United States)

    Burchfield, Mitchel Talmadge

    The purpose of this dissertation is to validate a stochastic model of human interactions which is part of a developmentalism paradigm. Incorporating elements of ancient and contemporary philosophy and science, developmentalism defines human development as a progression of increasing competence and utilizes compatible theories of developmental psychology, cognitive psychology, educational psychology, social psychology, curriculum development, neurology, psychophysics, and physics. To validate a stochastic model of human interactions, the study addressed four research questions: (a) Does attitude vary over time? (b) What are the distributional assumptions underlying attitudes? (c) Does the stochastic model, {-}N{intlimitssbsp{-infty}{infty}}varphi(chi,tau)\\ Psi(tau)dtau, have utility for the study of attitudinal distributions and dynamics? (d) Are the Maxwell-Boltzmann, Fermi-Dirac, and Bose-Einstein theories applicable to human groups? Approximately 25,000 attitude observations were made using the Semantic Differential Scale. Positions of individuals varied over time and the logistic model predicted observed distributions with correlations between 0.98 and 1.0, with estimated standard errors significantly less than the magnitudes of the parameters. The results bring into question the applicability of Fisherian research designs (Fisher, 1922, 1928, 1938) for behavioral research based on the apparent failure of two fundamental assumptions-the noninteractive nature of the objects being studied and normal distribution of attributes. The findings indicate that individual belief structures are representable in terms of a psychological space which has the same or similar properties as physical space. The psychological space not only has dimension, but individuals interact by force equations similar to those described in theoretical physics models. Nonlinear regression techniques were used to estimate Fermi-Dirac parameters from the data. The model explained a high degree

  4. Plant-based antimicrobial studies--methods and approaches to study the interaction between natural products.

    Science.gov (United States)

    van Vuuren, Sandy; Viljoen, Alvaro

    2011-07-01

    The therapeutic value of synergistic interactions has been known since antiquity, and many different cultural healing systems still rely on this principle in the belief that combination therapy may enhance efficacy. This paper intends to provide an overview, from an antimicrobial perspective, on the research undertaken and interactive principles involved in pharmacognosy studies. Methods used to determine antimicrobial interactions include basic combination studies, the sum of the fractional inhibitory concentration index (ΣFIC), isobole interpretations, and death kinetic (time-kill) assays. The various interactions are discussed with reference to molecules, different plant parts or fractions, different plant species, and combinations with nonbotanical antimicrobial agents. It is recommended for future development in the field of phytosynergy that consideration should be given to the selection criteria for the two inhibitors. A more conservative approach should be adopted when classifying synergy. When examining interactions in plant-based studies, antagonistic interactions should not be ignored. Combinations involving more than two test samples should be examined where applicable, and very importantly, the mechanism of action of synergistic interactions should be given precedence. It is encouraging to observe the upsurge in papers exploring the complex interactions of medicinal plants, and undoubtedly this will become increasingly important in our continued quest to understand the mechanism of action of phytotherapy. The scientific validation of efficacious antimicrobial combinations could lead to patentable entities making research in the field of phytosynergy not only academically rewarding but also commercially relevant.

  5. Interactions

    DEFF Research Database (Denmark)

    The main theme of this anthology is the unique interaction between mathematics, physics and philosophy during the beginning of the 20th century. Seminal theories of modern physics and new fundamental mathematical structures were discovered or formed in this period. Significant physicists...... such as Lorentz and Einstein as well as mathematicians such as Poincare, Minkowski, Hilbert and Weyl contributed to this development. They created the new physical theories and the mathematical disciplines that play such paramount roles in their mathematical formulations. These physicists and mathematicians were...

  6. Spectroscopic Electrochemical Studies of Interaction Between Fuchsin Basic DNA

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Visible spectroscopic and electrochemical methods were used to study the interactions between DNA and fuchsin basic(FB). FB has an irreversible electro-oxidation peak in 5 mmol/L Tris-HCl buffer solution at pH = 7.4 on a glassy carbon electrode(GCE). After adding certain concentration of dsDNA, the oxidation peak current of FB decreases, but the peak potential hardly changs. The visible absorption spectroscopic study shows that the binding mode of FB to dsDNA is intercalative binding and electrostatic binding when the ratio of the concentration of dsDNA to FB is smaller than 0. 2, and a new substance, which produces a new absorption peak, is obtained via a covalent binding between dsDNA and FB apart from intercalative binding and electrostatic binding when the ratio of the concentration of dsDNA to FB is larger than 0. 2. The visible absorption spectra varies no longer when the ratio of the concentration of dsDNA to FB is larger than 1.5. A mean binding ratio of dsDNA to FB was determined to be 1.4: 1,suggesting that two complexes FB-dsDNA and FB-2dsDNA be formed. The interaction between FB and ssDNA was only electrostatic binding. The more powerful interaction of FB with dsDNA than with ssDNA may be applied for the recognition of dsDNA and ssDNA, and in DNA biosensor as hybridization indicator.

  7. Susceptibility and gene interaction study of the angiotensin II type 1 receptor (AGTR1 gene polymorphisms with non-alcoholic fatty liver disease in a multi-ethnic population.

    Directory of Open Access Journals (Sweden)

    Shamsul Mohd Zain

    Full Text Available Angiotensin II type 1 receptor (AGTR1 has been reported to play a fibrogenic role in non-alcoholic fatty liver disease (NAFLD. In this study, five variants of the AGTR1 gene (rs3772622, rs3772627, rs3772630, rs3772633, and rs2276736 were examined for their association with susceptibility to NAFLD. Subjects made up of 144 biopsy-proven NAFLD patients and 198 controls were genotyped using TaqMan assays. The liver biopsy specimens were histologically graded and scored according to the method of Brunt. Single locus analysis in pooled subjects revealed no association between each of the five variants with susceptibility to NAFLD. In the Indian ethnic group, the rs2276736, rs3772630 and rs3772627 appear to be protective against NAFLD (p = 0.010, p = 0.016 and p = 0.026, respectively. Haplotype ACGCA is shown to be protective against NAFLD for the Indian ethnic subgroup (p = 0.03. Gene-gene interaction between the AGTR1 gene and the patatin-like phospholipase domain-containing 3 (PNPLA3 gene, which we previously reported as associated with NAFLD in this sample, showed a strong interaction between AGTR1 (rs3772627, AGTRI (rs3772630 and PNPLA3 (rs738409 polymorphisms on NAFLD susceptibility (p = 0.007. Further analysis of the NAFLD patients revealed that the G allele of the AGTR1 rs3772622 is associated with increased fibrosis score (p = 0.003. This is the first study that replicates an association between AGTR1 polymorphism and NAFLD, with further details in histological features of NAFLD. There is lack of evidence to suggest an association between any of the five variants of the AGTR1 gene and NAFLD in the Malays and Chinese. In the Indians, the rs2276736, rs3772630 and rs3772627 appear to protect against NAFLD. We report novel findings of an association between the G allele of the rs3772622 with occurrence of fibrosis and of the gene-gene interaction between AGTR1gene and the much-studied PNPLA3 gene.

  8. Susceptibility and gene interaction study of the angiotensin II type 1 receptor (AGTR1) gene polymorphisms with non-alcoholic fatty liver disease in a multi-ethnic population.

    Science.gov (United States)

    Zain, Shamsul Mohd; Mohamed, Zahurin; Mahadeva, Sanjiv; Rampal, Sanjay; Basu, Roma Choudhury; Cheah, Phaik-Leng; Salim, Agus; Mohamed, Rosmawati

    2013-01-01

    Angiotensin II type 1 receptor (AGTR1) has been reported to play a fibrogenic role in non-alcoholic fatty liver disease (NAFLD). In this study, five variants of the AGTR1 gene (rs3772622, rs3772627, rs3772630, rs3772633, and rs2276736) were examined for their association with susceptibility to NAFLD. Subjects made up of 144 biopsy-proven NAFLD patients and 198 controls were genotyped using TaqMan assays. The liver biopsy specimens were histologically graded and scored according to the method of Brunt. Single locus analysis in pooled subjects revealed no association between each of the five variants with susceptibility to NAFLD. In the Indian ethnic group, the rs2276736, rs3772630 and rs3772627 appear to be protective against NAFLD (p = 0.010, p = 0.016 and p = 0.026, respectively). Haplotype ACGCA is shown to be protective against NAFLD for the Indian ethnic subgroup (p = 0.03). Gene-gene interaction between the AGTR1 gene and the patatin-like phospholipase domain-containing 3 (PNPLA3) gene, which we previously reported as associated with NAFLD in this sample, showed a strong interaction between AGTR1 (rs3772627), AGTRI (rs3772630) and PNPLA3 (rs738409) polymorphisms on NAFLD susceptibility (p = 0.007). Further analysis of the NAFLD patients revealed that the G allele of the AGTR1 rs3772622 is associated with increased fibrosis score (p = 0.003). This is the first study that replicates an association between AGTR1 polymorphism and NAFLD, with further details in histological features of NAFLD. There is lack of evidence to suggest an association between any of the five variants of the AGTR1 gene and NAFLD in the Malays and Chinese. In the Indians, the rs2276736, rs3772630 and rs3772627 appear to protect against NAFLD. We report novel findings of an association between the G allele of the rs3772622 with occurrence of fibrosis and of the gene-gene interaction between AGTR1gene and the much-studied PNPLA3 gene.

  9. Pharmacokinetic interaction study between benazepril and amlodipine in healthy subjects.

    Science.gov (United States)

    Sun, J X; Cipriano, A; Chan, K; John, V A

    1994-01-01

    Pharmacokinetic interaction between benazepril (ACE inhibitor) and amlodipine (calcium channel blocker) was studied in 12 healthy subjects. Single doses of benazepril hydrochloride (10-mg tablet) and amlodipine besylate (tablet equivalent to 5 mg amlodipine) were administered alone or in combination according to a three-way, Latin-Square, randomized cross-over design. Serial blood samples were collected following each administration for the determination of benazepril and its active metabolite benazeprilat and amlodipine. The mean values of AUC (0-4 h), Cmax and Tmax for benazepril given as combination versus given alone were 161 vs 140 ng.h.ml-1, 168 vs 149 ng.ml-1, and 0.5 vs 0.6 h. The mean values of AUC (0-24 h), Cmax and Tmax for benazeprilat after benazepril given as combination versus given alone were 1470 vs 1410 ng.h.ml-1, 292 vs 257 ng.ml-1, and 1.7 vs 1.5 h. The mean values of AUC (0-144 h), Cmax and Tmax for amlodipine given as combination versus given alone were 118 vs 114 ng.h.ml-1, 2.5 vs 2.3 ng.ml-1, and 8.3 vs 9.0 h. The differences in these pharmacokinetic parameters between the combination and monotherapy treatments were not statistically significant based on ANOVA. The results of this study indicate that no pharmacokinetic interaction existed between the two drugs.

  10. Study on the fine control of atoms by coherent interaction

    Energy Technology Data Exchange (ETDEWEB)

    Han, Jae Min; Rho, S. P.; Park, H. M.; Lee, K. S.; Rhee, Y. J.; Yi, J. H.; Jeong, D. Y.; Ko, K. H.; Lee, J. M.; Kim, M.K

    2000-01-01

    Study on one dimensional atom cooling and trapping process which is basic to the development of atom manipulation technology has been performed. A Zeeman slower has been designed and manufactured for efficient cooling of atoms. The speed of atoms finally achieved is as slow as 15 m/s with proper cooling conditions. By six circularly-polarized laser beams and quadrupole magnetic field, the atoms which have been slowed down by zeeman slower have been trapped in a small spatial region inside MOT. The higher the intensity of the slowing laser is the more is the number of atoms slowed and the maximum number of atoms trapped has been 10{sup 8}. The atoms of several tens of {mu}K degree have been trapped by controlling the intensity of trapping laser and intensity gradient of magnetic field. EIT phenomena caused by atomic coherent interaction has been studied for the development of atom optical elements. For the investigation of the focusing phenomena induced by the coherent interaction, experimental measurements and theoretical analysis have been performed. Spatial dependency of spectrum and double distribution signal of coupling laser have been obtained. The deflection of laser beams utilizing the EIT effects has also been considered. (author)

  11. Granuloma Transplantation: An Approach to Study Mycobacterium-Host Interactions

    Directory of Open Access Journals (Sweden)

    Jeff Scott Harding

    2011-12-01

    Full Text Available The host-pathogen biology during infection with Mycobacterium tuberculosis is incredibly complex and despite accelerating progress in research, remains poorly understood. Our limited understanding hinders the development of new drugs, next generation vaccines, and novel therapies. The granuloma is the site where mycobacteria are both controlled and allowed to persist, but it remains one of the least studied aspects of the host-pathogen relationship. Here, we review the development, application, potential uses, and limitations of a novel model of granuloma transplantation as a tool to study specific host-pathogen interactions that have been difficult to probe. Application of this new model has already contributed to our understanding of granuloma cell traffic, repopulation, and the relationship between systemic immunity and mycobacteria-containing granulomas. The data collected highlight the dynamic interaction between systemic and local immune processes and support a paradigm that defines the granuloma as a highly dynamic structure. Granuloma transplantation also has special potential as a novel latency model that can contribute to our understanding of host protection factors and bacterial mutants, and serve as a platform for drug testing.

  12. Nucleic acid-lipid membrane interactions studied by DSC.

    Science.gov (United States)

    Giatrellis, Sarantis; Nounesis, George

    2011-01-01

    The interactions of nucleic acids with lipid membranes are of great importance for biological mechanisms as well as for biotechnological applications in gene delivery and drug carriers. The optimization of liposomal vectors for clinical use is absolutely dependent upon the formation mechanisms, the morphology, and the molecular organization of the lipoplexes, that is, the complexes of lipid membranes with DNA. Differential scanning calorimetry (DSC) has emerged as an efficient and relatively easy-to-operate experimental technique that can straightforwardly provide data related to the thermodynamics and the kinetics of the DNA-lipid complexation and especially to the lipid organization and phase transitions within the membrane. In this review, we summarize DSC studies considering nucleic acid-membrane systems, accentuating DSC capabilities, and data analysis. Published work involving cationic, anionic, and zwitterionic lipids as well as lipid mixtures interacting with RNA and DNA of different sizes and conformations are included. It is shown that despite limitations, issues such as DNA- or RNA-induced phase separation and microdomain lipid segregation, liposomal aggregation and fusion, alterations of the lipid long-range molecular order, as well as membrane-induced structural changes of the nucleic acids can be efficiently treated by systematic high-sensitivity DSC studies.

  13. Study of the interaction of kaempferol with bovine serum albumin

    Science.gov (United States)

    Tian, Jianniao; Liu, Jiaqin; Tian, Xuan; Hu, Zhide; Chen, Xingguo

    2004-03-01

    The binding of kaempferol with bovine serum albumin (BSA) was investigated at three temperatures, 296, 310 and 318 K, by the fluorescence, circular dichroism (CD) and Fourier transform infrared spectroscopy (FT-IR) at pH 7.40. The CD and FT-IR studies indicate that kaempferol binds strongly to BSA. The association constant K was determined by Stern-Volmer equation based on the quenching of the fluorescence BSA in the presence of kaempferol. The thermodynamic parameters were calculated according to the dependence of enthalpy change on the temperature as follows: Δ H0 and Δ S0 possess small negative (-1.694 kJ/mol) and positive values (88.814 J/mol K), respectively. According to the displacement experimental and the thermodynamic results, it is considered that kaempferol binding site II (subdomain III) mainly by hydrophobic interaction. The results studied by FT-IR and CD experiments indicate that the secondary structures of the protein have been changed by the interaction of kaempferol with BSA. The distance between the tryptophan residues in BSA and kaempferol bound to site II was estimated to be 2.78 nm using Foster's equation on the basis of fluorescence energy transfer.

  14. Nucleic acid-lipid membrane interactions studied by DSC

    Directory of Open Access Journals (Sweden)

    Sarantis Giatrellis

    2011-01-01

    Full Text Available The interactions of nucleic acids with lipid membranes are of great importance for biological mechanisms as well as for biotechnological applications in gene delivery and drug carriers. The optimization of liposomal vectors for clinical use is absolutely dependent upon the formation mechanisms, the morphology, and the molecular organization of the lipoplexes, that is, the complexes of lipid membranes with DNA. Differential scanning calorimetry (DSC has emerged as an efficient and relatively easy-to-operate experimental technique that can straightforwardly provide data related to the thermodynamics and the kinetics of the DNA-lipid complexation and especially to the lipid organization and phase transitions within the membrane. In this review, we summarize DSC studies considering nucleic acid-membrane systems, accentuating DSC capabilities, and data analysis. Published work involving cationic, anionic, and zwitterionic lipids as well as lipid mixtures interacting with RNA and DNA of different sizes and conformations are included. It is shown that despite limitations, issues such as DNA- or RNA-induced phase separation and microdomain lipid segregation, liposomal aggregation and fusion, alterations of the lipid long-range molecular order, as well as membrane-induced structural changes of the nucleic acids can be efficiently treated by systematic high-sensitivity DSC studies.

  15. Study of oral clefts: Indication of gene-environment interaction

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, S.J.; Beaty, T.H.; Panny, S. [Johns Hopkins Univ., Baltimore, MD (United States)] [and others

    1994-09-01

    In this study of infants with isolated birth defects, 69 cleft palate-only (CPO) cases, 114 cleft lip with or without palate (CL/P), and 284 controls with non-cleft birth defects (all born in Maryland during 1984-1992) were examined to test for associations among genetic markers and different oral clefts. Modest associations were found between transforming growth factor {alpha} (TGF{alpha}) marker and CPO, as well as that between D17S579 (Mfd188) and CL/P in this study. The association between TGF{alpha} marker and CPO reflects a statistical interaction between mother`s smoking and child`s TGF{alpha} genotype. A significantly higher risk of CPO was found among those reporting maternal smoking during pregnancy and carrying less common TGF{alpha} TaqI allele (odds ratio=7.02 with 95% confidence interval 1.8-27.6). This gene-environment interaction was also found among those who reported no family history of any type of birth defect (odds ratio=5.60 with 95% confidence interval 1.4-22.9). Similar associations were seen for CL/P, but these were not statistically significant.

  16. Interactive Tutoring in Blended Studies: Hindrances and Solutions

    Directory of Open Access Journals (Sweden)

    Asim Ismail Ilyas (Al-Titinchy

    2016-01-01

    Full Text Available This paper distinguishes between traditional teaching known as lecturing (the teacher centered approach; and tutoring (the contemporary technology-oriented interactive teaching/learning approach. It is based on the implementation of tutoring strategies of ‘blended studies’  at the Arab Open University. It investigates the application of modern interactive teaching/learning strategies, specifying some hindering factors in the AOU-Jordan Branch context. The factors include four variables: tutors, students, course material and assessment. The paper is based on qualitative research in terms of a real teaching/leaning context, using both observation and conversation with learners, besides the use of some quantitative data retrieved from a questionnaire in which learners’ views are sought regarding a number of relevant matters. A number of suggested solutions related to each of the hindering factors are presented, which if applied, may secure shifting the balance of the teaching/learning process to a more interactive technology-based tutoring level, which in turn will enhance learners’ opportunities for the attainment of better academic standards, and secure a higher degree of achievement of the shared educational goals of learners and the educational institution they study in.                                                                                                                                                       Keywords: blended studies, interactional teaching, lecturing, tutoring, course material, English language skills

  17. Gene-gene interaction in asthma : IL4RA and IL13 in a Dutch population with asthma

    NARCIS (Netherlands)

    Howard, TD; Koppelman, GH; Zheng, SQL; Postma, DS; Meyers, DA; Bleecker, ER

    Asthma is a common respiratory disease that is characterized by variable airways obstruction caused by acute and chronic bronchial inflammation; associated phenotypes include bronchial hyperresponsiveness (BHR), elevated total serum immunoglobulin E (IgE) levels, and skin tests positive to common

  18. To Control False Positives in Gene-Gene Interaction Analysis: Two Novel Conditional Entropy-Based Approaches: e81984

    National Research Council Canada - National Science Library

    Xiaoyu Zuo; Shaoqi Rao; An Fan; Meihua Lin; Haoli Li; Xiaolei Zhao; Jiheng Qin

    2013-01-01

    ...) were developed for detecting non-linear dependence between genetic loci, but they are potentially at the risk of inflated false positive error, in particular when the main effects at one or both loci are salient...

  19. To control false positives in gene-gene interaction analysis: two novel conditional entropy-based approaches

    National Research Council Canada - National Science Library

    Zuo, Xiaoyu; Rao, Shaoqi; Fan, An; Lin, Meihua; Li, Haoli; Zhao, Xiaolei; Qin, Jiheng

    2013-01-01

    ...) were developed for detecting non-linear dependence between genetic loci, but they are potentially at the risk of inflated false positive error, in particular when the main effects at one or both loci are salient...

  20. Studying Genes

    Science.gov (United States)

    ... NIGMS NIGMS Home > Science Education > Studying Genes Studying Genes Tagline (Optional) Middle/Main Content Area Other Fact Sheets What are genes? Genes are segments of DNA that contain instructions ...

  1. Relevance Epistasis Network of Gastritis for Intra-chromosomes in the Korea Associated Resource (KARE Cohort Study

    Directory of Open Access Journals (Sweden)

    Hyun-hwan Jeong

    2014-12-01

    Full Text Available Gastritis is a common but a serious disease with a potential risk of developing carcinoma. Helicobacter pylori infection is reported as the most common cause of gastritis, but other genetic and genomic factors exist, especially single-nucleotide polymorphisms (SNPs. Association studies between SNPs and gastritis disease are important, but results on epistatic interactions from multiple SNPs are rarely found in previous genome-wide association (GWA studies. In this study, we performed computational GWA case-control studies for gastritis in Korea Associated Resource (KARE data. By transforming the resulting SNP epistasis network into a gene-gene epistasis network, we also identified potential gene-gene interaction factors that affect the susceptibility to gastritis.

  2. Isotope labeling for NMR studies of macromolecular structure and interactions

    Energy Technology Data Exchange (ETDEWEB)

    Wright, P.E. [Scripps Research Institute, La Jolla, CA (United States)

    1994-12-01

    Implementation of biosynthetic methods for uniform or specific isotope labeling of proteins, coupled with the recent development of powerful heteronuclear multidimensional NMR methods, has led to a dramatic increase in the size and complexity of macromolecular systems that are now amenable to NMR structural analysis. In recent years, a new technology has emerged that combines uniform {sup 13}C, {sup 15}N labeling with heteronuclear multidimensional NMR methods to allow NMR structural studies of systems approaching 25 to 30 kDa in molecular weight. In addition, with the introduction of specific {sup 13}C and {sup 15}N labels into ligands, meaningful NMR studies of complexes of even higher molecular weight have become feasible. These advances usher in a new era in which the earlier, rather stringent molecular weight limitations have been greatly surpassed and NMR can begin to address many central biological problems that involve macromolecular structure, dynamics, and interactions.

  3. Study of Host–Microbe Interactions in Zebrafish

    Science.gov (United States)

    Milligan-Myhre, Kathryn; Charette, Jeremy R.; Phennicie, Ryan T.; Stephens, W. Zac; Rawls, John F.; Guillemin, Karen; Kim, Carol H.

    2015-01-01

    All animals are ecosystems, home to diverse microbial populations. Animal-associated microbes play important roles in the normal development and physiology of their hosts, but can also be agents of infectious disease. Traditionally, mice have been used to study pathogenic and beneficial associations between microbes and vertebrate animals. The zebrafish is emerging as a valuable new model system for host-microbe interaction studies, affording researchers with the opportunity to survey large populations of hosts and to visualize microbe-host associations at a cellular level in living animals. This chapter provides detailed protocols for the analysis of zebrafish-associated microbial communities, the derivation and husbandry of germ-free zebrafish, and the modeling of infectious disease in different stages of zebrafish development via different routes of inoculation. These protocols offer a starting point for researchers to address a multitude of questions about animals’ coexistence with microorganisms. PMID:21951527

  4. Numerical study on the interaction between supercavitation and turbulence

    Science.gov (United States)

    Liu, Han; Xiao, Zuoli; Shen, Lian

    2016-11-01

    Supercavitation uses a bubble of gas inside a liquid large enough to encompass an object travelling through the liquid so that the skin friction on the object can be greatly reduced and high speed can be obtained. In this study, computational fluid dynamics is used to investigate the interaction between supercavitation and turbulence. The study builds on an in-house simulation code that uses the coupled level set and volume of fluid method to accurately capture the interface between the water and gas phases. A ventilated disk cavitator is used for the bubble generation, and it is modelled by a sharp interface immersed boundary method. Turbulence in the incoming flow is generated by a grid of small spheres upstream. Based on the simulation data, the influence of turbulence on the supercavitation and the underlying mechanisms are analyzed.

  5. Study on the fine control of atoms by coherent interaction

    Energy Technology Data Exchange (ETDEWEB)

    Han, Jae Min; Rho, S. P.; Park, H. M.; Lee, K. S.; Rhee, Y. J.; Yi, J. H.; Jeong, D. Y.; Jung, E. C.; Choe, A. S.; Lee, J. M

    1998-01-01

    The basic research on the control of atoms using the coherent interaction, such as the development of the generator of the thermal atomic beam with high directionality, the photodeflection of atomic beam and the coherent excitation of atoms, has been performed. Yb atomic beam with small divergence was generated and the deflection mechanism of the atomic beam was studied by using a broad band dye laser and a narrow band laser. It has been proved that the single mode dye laser with narrow bandwidth was suitable for deflection of atoms but the frequency locking system was indispensable. And the apparatus for intermodulated optogalvanic (IMOG) experiment was developed and the high resolution optogalvanic spectroscopy was studied for laser frequency stabilization. (author). 74 refs., 1 tab., 26 figs

  6. Experimental and theoretical studies of interactions between Si{7} clusters

    Science.gov (United States)

    Gynz-Rekowski, F. V.; Quester, W.; Dietsche, R.; Lim, D. C.; Bertram, N.; Fischer, T.; Ganteför, G.; Schach, M.; Nielaba, P.; Kim, Y. D.

    2007-12-01

    The possibility of using magic Si7 clusters to form a cluster material was studied experimentally and theoretically. In experiments Si7 clusters were deposited on carbon surfaces, and the electronic structure and chemical properties of the deposited clusters were measured using X-ray photoelectron spectroscopy (XPS). A non bulk-like electronic structure of Si7 was found in the Si 2p core level spectra. Si7 is suggested to form a more stable structure than the non-magic Si8 cluster and Si atoms upon deposition on carbon surfaces. Theoretically it was possible to study the interaction between the clusters without the effect of a surface. Density functional theory (DFT) calculations of potential curves of two free Si7 clusters approaching each other in various orientations hint at the formation of cluster materials rather than the fusion of clusters forming bulk-like structures.

  7. SNP interaction detection with Random Forests in high-dimensional genetic data

    Directory of Open Access Journals (Sweden)

    Winham Stacey J

    2012-07-01

    Full Text Available Abstract Background Identifying variants associated with complex human traits in high-dimensional data is a central goal of genome-wide association studies. However, complicated etiologies such as gene-gene interactions are ignored by the univariate analysis usually applied in these studies. Random Forests (RF are a popular data-mining technique that can accommodate a large number of predictor variables and allow for complex models with interactions. RF analysis produces measures of variable importance that can be used to rank the predictor variables. Thus, single nucleotide polymorphism (SNP analysis using RFs is gaining popularity as a potential filter approach that considers interactions in high-dimensional data. However, the impact of data dimensionality on the power of RF to identify interactions has not been thoroughly explored. We investigate the ability of rankings from variable importance measures to detect gene-gene interaction effects and their potential effectiveness as filters compared to p-values from univariate logistic regression, particularly as the data becomes increasingly high-dimensional. Results RF effectively identifies interactions in low dimensional data. As the total number of predictor variables increases, probability of detection declines more rapidly for interacting SNPs than for non-interacting SNPs, indicating that in high-dimensional data the RF variable importance measures are capturing marginal effects rather than capturing the effects of interactions. Conclusions While RF remains a promising data-mining technique that extends univariate methods to condition on multiple variables simultaneously, RF variable importance measures fail to detect interaction effects in high-dimensional data in the absence of a strong marginal component, and therefore may not be useful as a filter technique that allows for interaction effects in genome-wide data.

  8. X-ray study of weak interactions in two flavonoids

    Indian Academy of Sciences (India)

    Deepak Sharma; Vivek K Gupta; Goutam Brahmachari; Sadhan Mondal; Arindam Gangopadhyay

    2007-10-01

    X-ray diffraction studies were carried out on single crystals of two flavonoids, viz. 5-hydroxy-6,7,4′-trimethoxyflavone, C18H16O6, (I) and 5-hydroxy-3,7,4′-trimethoxyflavone, C18H16O6, (II). Crystal structures of both the flavonoids were solved by direct methods and refined by full-matrix least-squares procedures. In both the molecules, the benzopyran moiety is planar. The dihedral angle between the phenyl ring and the benzopyran portion is 5.50(4)° in (I) and 29.11(5)° in (II). In (I), the crystal packing is influenced by O–H…O hydrogen bonds, and weak C–H…O and $\\pi \\ldots \\pi$ interactions whereas in (II) the crystal structure is stabilized by the presence of four intermolecular short contacts of the type C–H…O. There is also one C–H$\\ldots \\pi$ hydrogen bond with H… centroid distance of < 2.7 Å. The molecules are further stabilized by – interactions.

  9. Study of interaction of tramadol with amlodipine in mice

    Science.gov (United States)

    Modi, Hiral; Mazumdar, Bipa; Bhatt, Jagatkumar

    2013-01-01

    Objective: To study a possible interaction between tramadol, an opioid analgesic and amlodipine, a dihydropyridine calcium channel blocker with proposed antinociceptive property. Materials and Methods: Albino mice of Haffkine strain were used for the study. The experiment was carried out using tail-flick method. Different doses of tramadol (50 mg/kg, 22.8 mg/kg and 10 mg/kg) were administered intraperitoneally to select the nonanalgesic dose. The animals were treated with different doses of amlodipine (2.5 mg/kg, 3.0 mg/kg, 3.5 mg/kg) to study its antinociceptive action. Combination of different doses of both the drugs were administered to study antinociceptive effect of the combination. Results: Tramadol, showed dose dependent antinociception which persisted for entire two hours of the study period. Antinociceptive action was seen with amlodipine at a dose of 3.5 mg/kg. Different doses of amlodipine (2.5 mg/kg, 3.0 mg/kg) in combination with the nonanalgesic dose of tramadol (10 mg/kg) produced a significant enhancement of antinociceptive effect of tramadol. Combination of 3.5 mg/kg dose of amlodipine with nonanalgesic dose of tramadol (10 mg/kg) further enhances antinociceptive activity. Conclusion: It is concluded that combination of amlodipine, a N - type calcium channel blocker, with tramadol produce significant enhancement of antinociceptive activity of tramadol. PMID:23543914

  10. Pharmacogenetic predictor of extrapyramidal symptoms induced by antipsychotics: multilocus interaction in the mTOR pathway.

    Science.gov (United States)

    Mas, S; Gassó, P; Ritter, M A; Malagelada, C; Bernardo, M; Lafuente, A

    2015-01-01

    Antipsychotic (AP) treatment-emergent extrapyramidal symptoms (EPS) are acute adverse reactions of APs. The aim of the present study is to analyze gene-gene interactions in nine genes related to the mTOR pathway, in order to develop genetic predictors of the appearance of EPS. 243 subjects (78 presenting EPS: 165 not) from three cohorts participated in the present study: Cohort 1, patients treated with risperidone, (n=114); Cohort 2, patients treated with APs other than risperidone (n=102); Cohort 3, AP-naïve patients with first-episode psychosis treated with risperidone, paliperidone or amisulpride, n=27. We analyzed gene-gene interactions by multifactor dimensionality reduction assay (MDR). In Cohort 1, we identified a four-way interaction, including the rs1130214 (AKT1), rs456998 (FCHSD1), rs7211818 (Raptor) and rs1053639 (DDIT4), that correctly predicted 97 of the 114 patients (85% accuracy). We validated the predictive power of the four-way interaction in Cohort 2 and in Cohort 3 with 86% and 88% accuracy respectively. We develop and validate a powerful pharmacogenetic predictor of AP-induced EPS. For the first time, the mTOR pathway has been related to EPS susceptibility and AP response. However, validation in larger and independent populations will be necessary for optimal generalization.

  11. A Case Study: Novel Group Interactions through Introductory Computational Physics

    CERN Document Server

    Obsniuk, Michael J; Caballero, Marcos D

    2015-01-01

    With the advent of high-level programming languages capable of quickly rendering three-dimensional simulations, the inclusion of computers as a learning tool in the classroom has become more prevalent. Although work has begun to study the patterns seen in implementing and assessing computation in introductory physics, more insight is needed to understand the observed effects of blending computation with physics in a group setting. In a newly adopted format of introductory calculus-based mechanics, called Projects and Practices in Physics, groups of students work on short modeling projects -- which make use of a novel inquiry-based approach -- to develop their understanding of both physics content and practice. Preliminary analyses of observational data of groups engaging with computation, coupled with synchronized computer screencast, has revealed a unique group interaction afforded by the practices specific to computational physics -- problem debugging.

  12. β-Cyclodextrin-promazine hydrochloride interaction: Conductometric and viscometric studies

    Directory of Open Access Journals (Sweden)

    Mohd. Sajid Ali

    2015-01-01

    Full Text Available Herein we have studied the interaction of β-cyclodextrin (β-CD with the amphiphilic drug promazine hydrochloride (PMZ by using conductimetry and viscometry. From the observed results it was concluded that critical micelle concentration (cmc of the pure drug was lower than the apparent critical micelle concentration (cmc∗ of the drug in the presence of β-CD. The cmc∗ increased on increasing the concentration of β-CD due to the encapsulation of the amphiphilic drug to the hydrophobic cavities of the β-CD which delayed the micelle formation. Viscosity of the solution decreased drastically on the addition of β-CD which further increased on increasing the drug solution. Free energies of micellization (ΔGmic were calculated with the help of degrees of micelle ionization and cmc obtained from the specific conductivity−[PMZ] plots. Micellization was found to be less spontaneous in the presence of cyclodextrin.

  13. Computational Study on the Stacking Interaction in Catechol Complexes

    Science.gov (United States)

    Estévez, Laura; Otero, Nicolás; Mosquera, Ricardo A.

    2009-09-01

    The stability and electron density topology of catechol complexes (dimers and tetramer) were studied using the MPW1B95 functional. The QTAIM analysis shows that both dimers (face to face and C-H/π one) display a different electronic origin. The formation of the former is accompanied by a significant change in the values of atomic electron dipole and quadrupole components, flattening the most diffuse part of the electron density distribution toward the molecular plane. A small electron population transfer is observed between catechol monomers connected by C-H/π interactions, whose QTAIM characterization does not differ from that of a weak hydrogen bond. Cooperative effects in the tetramer on binding energies are small and negligible for bond properties and charge transfer. Nevertheless, they are significant on atomic electron populations.

  14. Thioxylated cyclosporin A for studying protein-drug interactions.

    Science.gov (United States)

    Lin, Weilin; Erdmann, Frank; Quintero, Andres; Fischer, Gunter; Zhang, Yixin

    2016-12-01

    Single atom substitution of cyclosporin A (CsA) through thioxylation has been used to study the structure-activity relationship of the immunosuppressive complex, involving the CsA receptor protein cyclophilin 18 (Cyp18) and the immunological target protein phosphatase calcineurin (CaN), illustrating the contributions of peptide backbone in protein-drug interaction. Moreover, the subtle difference between thioxylation positions in CsA has led to a remarkable change in the quenching effect on Cyp18 intrinsic fluorescence. Using the thioxylated compound Cs7 as an isosteric derivative of CsA in competition assay, the experiment has led to the determination of koff value in solution. Whereas the conformational heterogeneity of CsA has been found to be associated with its two-phase binding kinetics to Cyp18, the dissociation rate of CsA from complex is independent from the initial ligand structure. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Interactive home telehealth and burns: A pilot study.

    Science.gov (United States)

    Hickey, Sean; Gomez, Jason; Meller, Benjamin; Schneider, Jeffery C; Cheney, Meredith; Nejad, Shamim; Schulz, John; Goverman, Jeremy

    2017-06-19

    The objective of this study is to review our experience incorporating Interactive Home Telehealth (IHT) visits into follow-up burn care. A retrospective review of all burn patients participating in IHT encounters over the course of 15 months was performed. Connections were established through secure video conferencing and call-routing software. Patients connected with a personal computer or tablet and providers connected with a desktop computer with a high-definition web camera. In some cases, high-definition digital images were emailed to the provider prior to the virtual consultation. For each patient, the following was collected: (1) patient and injury demographics (diagnosis, prognosis, and clinical management), (2) total number of encounters, (3) service for each encounter (burn, psychiatry, and rehabilitation), (4) length of visit, including travel distance and time saved and, (5) complications, including re-admissions and connectivity issues. 52 virtual encounters were performed with 31 patients during the first year of the pilot project from March 2015 to June 2016. Mean age of the participant was 44 years (range 18-83 years). Mean total burn surface area of the participant was 12% (range 1-80%). Average roundtrip travel distance saved was 188 miles (range 4-822 miles). Average round trip travel time saved was 201min (range 20-564min). There were no unplanned re-admissions and no complications. Five connectivity issues were reported, none of which prevented completion of the visit. Interactive Home Telehealth is a safe and feasible modality for delivering follow-up care to burn patients. Burn care providers benefit from the potential to improve outpatient clinic utilization. Patients benefit from improved access to multiple members of their specialized burn care team, as well as cost-reductions for patient travel expenses. Future studies are needed to ensure patient and provider satisfaction and to further validate the significance, cost-effectiveness and

  16. Experimental Studies of Elementary Particle Interactions at High Energies

    Energy Technology Data Exchange (ETDEWEB)

    Goulianos, Konstantin [The Rockefeller University

    2013-07-31

    This is the final report of a program of research on ``Experimental Studies of Elementary Particle Interactions at High Energies'' of the High Energy Physics (HEP) group of The Rockefeller University. The research was carried out using the Collider Detector at Fermilab (CDF) and the Compact Muon Solenoid (CMS) detector at the Large Hadron Collider (LHC) at CERN. Three faculty members, two research associates, and two postdoctoral associates participated in this project. At CDF, we studied proton-antiproton collisions at an energy of 1.96 TeV. We focused on diffractive interactions, in which the colliding antiproton loses a small fraction of its momentum, typically less than 1%, while the proton is excited into a high mass state retaining its quantum numbers. The study of such collisions provides insight into the nature of the diffractive exchange, conventionally referred to as Pomeron exchange. In studies of W and Z production, we found results that point to a QCD-based interpretation of the diffractive exchange, as predicted in a data-driven phenomenology developed within the Rockefeller HEP group. At CMS, we worked on diffraction, supersymmetry (SUSY), dark matter, large extra dimensions, and statistical applications to data analysis projects. In diffraction, we extended our CDF studies to higher energies working on two fronts: measurement of the single/double diffraction and of the rapidity gap cross sections at 7 TeV, and development of a simulation of diffractive processes along the lines of our successful model used at CDF. Working with the PYTHIA8 Monte Carlo simulation authors, we implemented our model as a PYTHIA8-MBR option in PYTHIA8 and used it in our data analysis. Preliminary results indicate good agreement. We searched for SUSY by measuring parameters in the Constrained Minimal Supersymmetric extension of the Standard Model (CMSSM) and found results which, combined with other experimental constraints and theoretical considerations, indicate

  17. Experimental studies of electron-phonon interactions in gallium nitride

    CERN Document Server

    Stanton, N M

    2001-01-01

    This thesis presents an experimental investigation of the electron-phonon interaction in GaN. Bulk epilayers, grown by MBE, and AIGaN/GaN heterostructure grown by MOCVD, have been studied. The energy relaxation rate for hot electrons has been measured over a wide range of temperatures, allowing both acoustic and optic phonon emission to be studied in GaN epilayers. Direct phonon measurements, both studying the emission and absorption processes, have been performed. Detection of phonons emitted when hot electrons relax their excess energy complements the measurements of relaxation rates. Absorption of acoustic phonons by the epilayers, using both fixed and extended metal film phonon sources, allowed investigation into the effectiveness of the 2k sub F cutoff in the low mobility layers. The experimental findings are compared with the predictions of theory. AIGaN/GaN heterostructures were characterised and measurements of the energy relaxation rate in the temperature range 4K-40K obtained. Excellent agreement wi...

  18. Flavonoid-surfactant interactions: A detailed physicochemical study

    Science.gov (United States)

    Singh, Onkar; Kaur, Rajwinder; Mahajan, Rakesh Kumar

    2017-01-01

    The aim of this article is to study the interactions between flavonoids and surfactants with attention of finding the probable location of flavonoids in micellar media that can be used for controlling their antioxidant behavior. In present study, the micellar and interfacial behavior of twin tailed anionic surfactants viz. sodium bis(2-ethylhexyl)sulfosuccinate (AOT) and sodium bis(2-ethylhexyl)phosphate (NaDEHP) in the presence of two flavonoids, namely quercetin (QUE) and kaempferol (KFL) have been studied by surface tension measurements. UV-visible, fluorescence and differential pulse voltammetric (DPV) measurements have been employed to predict the probable location of flavonoids (QUE/KFL) within surfactant (AOT/NaDEHP) aggregates. Dynamic light scattering (DLS) measurements further confirmed the solubilization of QUE/KFL in AOT/NaDEHP aggregates deduced from increased hydrodynamic diameter (Dh) of aggregates in the presence of flavonoids. Both radical scavenging activity (RSA) and degradation rate constant (k) of flavonoids are found to be higher in NaDEHP micelles as compared to AOT micelles.

  19. Interaction of Boron Clusters with Oxygen: a DFT Study

    Science.gov (United States)

    Salavitabar, Kamron; Boggavarapu, Kiran; Kandalam, Anil

    A controlled combustion involving aluminum nanoparticles has often been the focus of studies in the field of solid fuel propellants. However very little focus has been given to the study of boron nanoparticles in controlled combustion. In contrast to aluminum nanoclusters, boron nanoclusters (Bn) are known to exhibit a planar geometries even at the size of n = 19 - 20, and thus offer a greater surface area for interaction with oxygen. Earlier experimental studies have shown that boron nanoclusters exhibit different reactivity with oxygen depending on their size and charge. In this poster, we present our recent density functional theory based results, focusing on the reactivity patterns of neutral and negatively charged B5 cluster with On, where n = 1 - 5; and B6 cluster with On (n = 1 - 2). The effect of charge on the reactivity of boron cluster, variation in the stability of product clusters, i e., neutral and negatively charged B5On (n = 1 - 5) and B6On (n = 1 - 2) are also examined. Financial Support from West Chester University Foundation under FaStR grant is acknowledged.

  20. Interaction, synergy and antagonism in prospective epidemiological studies

    OpenAIRE

    Orellana, Juan J.; Departamento de Salud Pública, Facultad de Medicina, Universidad de La Frontera. Temuco, Chile. Centro de Capacitación Investigación y Gestión en Salud para la Medicina Basada en Evidencias (CIGES), Facultad de Medicina, Universidad de La Frontera. Temuco, Chile. Magister en Salud Pública.; Kaufman, Jay S.; Department of Epidemiology, Biostatistics and Occupational Health, McGill University. Quebec, Canada. PhD en Epidemiología.; Pino, Paulina; Escuela de Salud Pública, Facultad de Medicina, Universidad de Chile. Santiago de Chile, Chile. doctor en Salud Pública.

    2014-01-01

    In public health there is a growing appreciation for the advantage of the additive scale to better understand the impacts of factors involved in a health event. It is necessary to always remember that the concept of statistical interaction is scale dependent. In the causal relationship between a response and the presence of two or more factors, the concepts interaction, synergy and antagonism are the key ideas. The aim of this note is to show an application of the concepts interaction, sy...

  1. Yakima River Species Interactions Studies Annual Report FY 1992.

    Energy Technology Data Exchange (ETDEWEB)

    Pearsons, Todd N.

    1993-08-01

    The Yakima Species Interactions Study (YSIS) was begun in September of 1989 to investigate species interactions among fish in response to proposed supplementation of salmon and steelhead in the Yakima Basin. Supplementation is defined as ''the use of artificial propagation in the attempt to maintain or increase natural production while maintaining the long term fitness of the target population, and keeping the ecological and genetic impacts on non-target populations within specified biological limits'' (BPA summary report series, 1992). Target populations are the populations of fish that will be supplemented and non-target populations are all other populations of fish. One of the goals of the proposed Yakima Fisheries Project (YFP) is to test the strategy of supplementation in the Yakima Basin. In a review of published literature and unpublished projects about supplementation, Miller et al. (1990) concluded ''Adverse impacts to wild stocks have been shown or postulated for about every type of hatchery fish introduction where the intent was to rebuild runs''. In Steward and Bjornn's (1990) review of the published literature, they stated that ''Genetic and ecological effects, and changes in productivity of the native stocks that can result from supplementation remain largely unmeasured''. Uncertainties about the effects supplementation in the upper Yakima basin may have on wild fish was the impetus for the initiation of the present studies. The YSIS has three main goals which are to: evaluate risks of ecological interactions to target and non-target populations (resolve critical uncertainties), contribute to the development of an interactions monitoring plan, and provide information that may be used to increase the probability that natural production of anadromous salmonids may be successfully increased. Information obtained will be used as the YFP planning process proceeds (adaptive management). A

  2. Sonic Onyx: Case Study of an Interactive Artwork

    Science.gov (United States)

    Ahmed, Salah Uddin; Jaccheri, Letizia; M'kadmi, Samir

    Software supported art projects are increasing in numbers in recent years as artists are exploring how computing can be used to create new forms of live art. Interactive sound installation is one kind of art in this genre. In this article we present the development process and functional description of Sonic Onyx, an interactive sound installation. The objective is to show, through the life cycle of Sonic Onyx, how a software dependent interactive artwork involves its users and raises issues related to its interaction and functionalities.

  3. Study of $\\pi^{-}$p Interactions with Neutral Final States

    CERN Multimedia

    2002-01-01

    This experiment is a study of the production of neutral particles or states decaying into photons in the reaction @p|- + p @A M|0 + n at SPS energies. \\\\ \\\\ Special attention is paid to the measurement of the production of heavy particles with hidden quantum numbers and of possible new heavy spinless states decaying into two photons. \\\\ \\\\ The large four-momentum transfer behaviour of binary processes involving known neutral mesons and the production of new meson resonances with high mass and spin will also be studied. Complex multiparticle final states will be analysed as a by-product.\\\\ \\\\ The central unit of the experimental set-up is a 4000 cell Cerenkov hodoscope spectrometer (GAMS) which allows the measurement of the momentum vector of each $\\gamma$ in a multigamma event. \\\\ \\\\ The longitudinal position of the interaction point in the liquid hydrogen target is measured by the Cerenkov light intensity. \\\\ \\\\ A guard system, made of scintillation counters and lead-glass Cerenkov counters, is used to trigg...

  4. Bicuspid aortic valve hemodynamics: a fluid-structure interaction study

    Science.gov (United States)

    Chandra, Santanu; Seaman, Clara; Sucosky, Philippe

    2011-11-01

    The bicuspid aortic valve (BAV) is a congenital defect in which the aortic valve forms with two leaflets instead of three. While calcific aortic valve disease (CAVD) also develops in the normal tricuspid aortic valve (TAV), its progression in the BAV is more rapid. Although studies have suggested a mechano-potential root for the disease, the native BAV hemodynamics remains largely unknown. This study aimed at characterizing BAV hemodynamics and quantifying the degree of wall-shear stress (WSS) abnormality on BAV leaflets. Fluid-structure interaction models validated with particle-image velocimetry were designed to predict the flow and leaflet dynamics in idealized TAV and BAV anatomies. Valvular function was quantified in terms of the effective orifice area. The regional leaflet WSS was characterized in terms of oscillatory shear index, temporal shear magnitude and temporal shear gradient. The predictions indicate the intrinsic degree of stenosis of the BAV anatomy, reveal drastic differences in shear stress magnitude and pulsatility on BAV and TAV leaflets and confirm the side- and site-specificity of the leaflet WSS. Given the ability of abnormal fluid shear stress to trigger valvular inflammation, these results support the existence of a mechano-etiology of CAVD in the BAV.

  5. Ideology and Interaction: Debating Determinisms in Literacy Studies

    Science.gov (United States)

    Collin, Ross; Street, Brian V.

    2014-01-01

    In this exchange, Street and Collin debate the merits of the interaction model of literacy that Collin outlined in a recent issue of Reading Research Quarterly. Built as a complement and a counter to Street's ideological model of literacy, Collin's interaction model defines literacies as technologies that coevolve with sociocultural…

  6. Aphid-plant interactions at phloem level, a behavioural study.

    NARCIS (Netherlands)

    Prado, E.C.

    1997-01-01

    Aphid-plant interactions occurring during plant penetration, or probing, have determined the evolution of these insects as well as the abilities of plants to survive huge densities of these insects. For aphids, as phloem sap feeders, the interactions at sieve element level must be of special importa

  7. Ideology and Interaction: Debating Determinisms in Literacy Studies

    Science.gov (United States)

    Collin, Ross; Street, Brian V.

    2014-01-01

    In this exchange, Street and Collin debate the merits of the interaction model of literacy that Collin outlined in a recent issue of Reading Research Quarterly. Built as a complement and a counter to Street's ideological model of literacy, Collin's interaction model defines literacies as technologies that coevolve with sociocultural…

  8. Preliminary Study on Cordycepin-DNA Interaction by Raman Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Jian Ya LING; Qin Zheng YANG; Shan Shan LUO; Yan LI; Chang Kai ZHANG

    2005-01-01

    The interaction of cordycepin with calf thymus DNA was investigated at physiological pH with drug/DNA molar ratio of 8. The Raman spectroscopy results indicated that the intercalation of high concentration cordycepin and the interaction of cordycepin with PO2 group led to a major reduction of B-form DNA structure in favor of A-form DNA.

  9. A Design Study of Direct-Touch Interaction for Exploratory 3D Scientific Visualization

    NARCIS (Netherlands)

    Klein, Tijmen; Gueniat, Florimond; Pastur, Luc; Vernier, Frederic; Isenberg, Tobias

    2012-01-01

    We present an interaction design study of several non-overlapping direct-touch interaction widgets, postures, and bi-manual techniques to support the needs of scientists who are exploring a dataset. The final interaction design supports navigation/zoom, cutting plane interaction, a drilling explorat

  10. A Design Study of Direct-Touch Interaction for Exploratory 3D Scientific Visualization

    NARCIS (Netherlands)

    Klein, Tijmen; Gueniat, Florimond; Pastur, Luc; Vernier, Frederic; Isenberg, Tobias

    2012-01-01

    We present an interaction design study of several non-overlapping direct-touch interaction widgets, postures, and bi-manual techniques to support the needs of scientists who are exploring a dataset. The final interaction design supports navigation/zoom, cutting plane interaction, a drilling explorat

  11. Yakima River Species Interactions Studies, Annual Report 1993.

    Energy Technology Data Exchange (ETDEWEB)

    Pearsons, Todd N.

    1994-12-01

    Species interactions research was initiated in 1989 to investigate ecological interactions among fish in response to proposed supplementation of salmon and steelhead in the upper Yakima River basin. Data have been collected prior to supplementation to characterize the rainbow trout population, predict the potential interactions that may occur as a result of supplementation, and develop methods to monitor interactions. Major topics of this report are associated with the life history of rainbow trout, interactions experimentation, and methods for sampling. This report is organized into nine chapters with a general introduction preceding the first chapter and a general discussion following the last chapter. This annual report summarizes data collected primarily by the Washington Department of Fish and Wildlife (WDFW) between January 1 and December 31, 1993 in the upper Yakima basin above Roza Dam, however these data were compared to data from previous years to identify preliminary trends and patterns. Major preliminary findings from each of the chapters included in this report are described.

  12. Theoretical Studies on the Interactions of Cations with Diazine

    Institute of Scientific and Technical Information of China (English)

    CHEN Xing; WU Wen-Peng; ZHANG Jing-Lai; CAO Ze-Xing

    2006-01-01

    Density functional theory and MP2 calculations have been used to determine the geometries, stabilities, binding energies, and dissociative properties of cation-diazine complexes Mn+-C4H4N2 (Mn+ = Li+, B+, Al+, Be2+, Mg2+, Ca2+). The calculated results indicate that most complexes are stable except the π complexes of Ca2+-pyridazine, Ca2+-pyrazine, Al+-pyrimidine and Al+-pyrimidine. The σ complexes are generally much more stable than their π counterparts. Among the π complexes, the cation-pyrazine π complexes have slightly higher stability. The nature of the ion-molecule interactions has been discussed by the natural bond orbital analysis and frontier molecular orbital interactions. In these σ complexes, there is stronger covalent interaction between B+ and diazine. In the selected π complexes, B+ and Be2+ have stronger covalent interaction with diazine, while the other cations mainly have electrostatic interaction with diazine.

  13. A STUDY ON THE WHEELSET/SLAB TRACK VERTICAL INTERACTION

    Directory of Open Access Journals (Sweden)

    Traian MAZILU

    2012-05-01

    Full Text Available This paper deals with the interaction between a moving wheelset and a slab track due to the short-pitch corrugated rail. The wheelset is modeled using a free-free Timoshenko beam with attached rigid bodies as the axle boxes, wheels and brake discs. The slab track model consists of elastically supported double Euler-Bernoulli beams. In fact, both wheelset and slab track are symmetric structures and the issue of the wheelset/slab track interaction is reduced to the wheel/rail interaction. The nonlinear equations of motion describing the wheelset/slab track interaction due to the short-pitch corrugated rail are solved using the time-domain Green’s functions method and the convolution theorem. The wheelset/slab track interaction due to the short-pitch corrugated rail exhibits a critical velocity when the vibration reaches the maximum level

  14. Transient interactions studied by NMR : iron sulfur proteins and their interaction partners

    NARCIS (Netherlands)

    Xu, Xingfu

    2009-01-01

    The interactions between proteins are of central importance for virtually every process in a living cell. It has long been a mystery how two proteins associate to form a complex in a complicated cellular context. Recently, it was found that an intermediate state called encounter state, of a protein

  15. Francium sources and traps for fundamental interaction studies

    Science.gov (United States)

    Stancari, G.; Atutov, S. N.; Calabrese, R.; Corradi, L.; Dainelli, A.; de Mauro, C.; Khanbekyan, A.; Mariotti, E.; Minguzzi, P.; Moi, L.; Sanguinetti, S.; Tomassetti, L.; Veronesi, S.

    2007-11-01

    Francium is one of the best candidates for atomic parity nonconservation (APNC) and for the search of permanent electric dipole moments (EDMs). APNC measurements test the weak force between electrons and nucleons at very low momentum transfers. They also represent a unique way to detect weak nucleon-nucleon interactions. EDMs are instead related to the time-reversal symmetry. Preliminary to these fundamental measurements are precision studies in atomic spectroscopy and the development of magneto-optical traps (MOT), which partially compensate for the lack of stable Fr isotopes. At LNL Legnaro, francium is produced by fusion of 100-MeV 18O with 197Au in a thick target, followed by evaporation of neutrons from the compound nucleus. Francium diffuses inside the hot target (1200 K) and is surface ionized for injection at 3 keV in an electrostatic beamline. Typically, we produce 1×106 (210Fr ions)/s for a primary flux of 1.5×1012 particles/s. We have studied Fr yields as a function of primary beam energy, intensity, and target temperature. Information on the efficiency of bulk diffusion, surface desorption and ionization is deduced. The beam then enters a Dryfilm-coated cell, where it is neutralized on a heated yttrium plate. The escape time of neutral Fr (diffusion + desorption) is approximately 20 s at 950 K, as measured with a dedicated setup. In the MOT, we use 6 orthogonal Ti:sapphire laser beams for the main pumping transition and 6 beams from a stabilized diode repumper. Fluorescence from trapped atoms is observed with a cooled CCD camera, in order to reach noise levels from stray light equivalent to approximately 50 atoms. Systematic tests are being done to improve the trapping efficiency. We plan to further develop Fr traps at LNL; in parallel, we will study APNC and EDM techniques and systematics with stable alkalis at Pisa, Siena, and Ferrara.

  16. Study on Human-Computer Interaction in Immersive Virtual Environment

    Institute of Scientific and Technical Information of China (English)

    段红; 黄柯棣

    2002-01-01

    Human-computer interaction is one of the most important issues in research of Virtual Environments. This paper introduces interaction software developed for a virtual operating environment for space experiments. Core components of the interaction software are: an object-oriented database for behavior management of virtual objects, a software agent called virtual eye for viewpoint control, and a software agent called virtual hand for object manipulation. Based on the above components, some instance programs for object manipulation have been developed. The user can observe the virtual environment through head-mounted display system, control viewpoint by head tracker and/or keyboard, and select and manipulate virtual objects by 3D mouse.

  17. A STUDY ON THE WHEELSET/SLAB TRACK VERTICAL INTERACTION

    OpenAIRE

    2012-01-01

    This paper deals with the interaction between a moving wheelset and a slab track due to the short-pitch corrugated rail. The wheelset is modeled using a free-free Timoshenko beam with attached rigid bodies as the axle boxes, wheels and brake discs. The slab track model consists of elastically supported double Euler-Bernoulli beams. In fact, both wheelset and slab track are symmetric structures and the issue of the wheelset/slab track interaction is reduced to the wheel/rail interaction. The n...

  18. Spectroscopic studies of interactions involving horseradish peroxidase and Tb3+.

    Science.gov (United States)

    Guo, Shaofen; Zhou, Qing; Lu, Tianhong; Ding, Xiaolan; Huang, Xiaohua

    2008-09-01

    The spectroscopic properties of interactions involving horseradish peroxidase (HRP) and Tb3+ in the simulated physiological solution was investigated with some electrochemical and spectroscopic methods, such as cyclic voltammetry (CV), circular dichroism (CD), X-ray photoelectron spectroscopy (XPS) and synchronous fluorescence (SF). It was found that Tb3+ can coordinate with oxygen atoms in carbonyl groups in the peptide chain of HRP, form the complex of Tb3+ and HRP (Tb-HRP), and then lead to the conformation change of HRP. The increase in the random coil content of HRP can disturb the microstructure of the heme active center of HRP, in which the planarity of the porphyrin cycle in the heme group is increased and then the exposure extent of the electrochemical active center is decreased. Thus Tb3+ can inhibit the electrochemical reaction of HRP and its electrocatalytic activity for the reduction of H2O2 at the Au/Cys/GC electrode. The changes in the microstructure of HRP obstructed the electron transfer of Fe(III) in the porphyrin cycle of the heme group, thus HRP catalytic activity is inhibited. The inhibition effect of Tb3+ on HRP catalytic activity is increased with the increasing of Tb3+ concentration. This study would provide some references for better understanding the rare earth elements and heavy metals on peroxidase toxicity in living organisms.

  19. Spectroscopic and molecular docking studies on chlorambucil interaction with DNA.

    Science.gov (United States)

    Charak, Sonika; Shandilya, Manish; Tyagi, Gunjan; Mehrotra, Ranjana

    2012-11-01

    Chlorambucil (CMB) is an anticancer drug used for the treatment of variety of cancers. Structural and conformational changes associated with DNA after binding with CMB were explored using spectroscopic techniques to get insight into the mechanism of action of CMB at molecular level. Different molar ratios of CMB-DNA complex were prepared with constant DNA concentration under physiological conditions. FTIR spectroscopy, UV-visible spectroscopy, CD spectroscopy and molecular docking studies were employed to determine the binding site and binding constant of CMB with DNA. The results show CMB binds DNA through nitrogenous bases (thymine, guanine and cytosine). The binding constant was calculated to be 1.3 × 10³ M⁻¹, which suggests weak binding of CMB with DNA double helix. FTIR and CD results show that CMB do not disturb native B-conformation of DNA and it continues to remain in its B conformation even at higher concentrations of CMB. The molecular docking results are in corroboration with our experimental results and provides structural insight into the interaction site. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Suprathermal helium associated with corotating interaction regions: A case study

    Science.gov (United States)

    Yu, J.; Berger, L.; Wimmer-Schweingruber, R. F.; Hilchenbach, M.; Kallenbach, R.; Klecker, B.; Guo, J.

    2016-03-01

    Enhancements of suprathermal particles observed at 1AU often can be related to Corotating Interaction Regions (CIRs). The compression regions associated with CIRs and their driven shocks which typically form at a few AU distance to the Sun can efficiently accelerate particles. If accelerated at the trailing edge of a CIR these particles can travel sunward along the ambient magnetic field and thus enhanced fluxes can be observed even if the acceleration region has passed over the spacecraft. We have analysed a CIR that has been observed at L1 by ACE/SWICS and SOHO/CELIAS/STOF on days 207 and 208 in 2003. The combination of SWICS and STOF data allowed us to study suprathermal Helium ranging from its onset at solar wind bulk energies up to 330 keV/nuc. Here we present our results for the temporal evolution of the flux, energy spectra and the He+/He++ ratio. In particular we present observational evidence for a turnover of the energy spectra at lower energies after the CIR passage which has been theoretically predicted but never been observed so far.

  1. Experimental studies of interaction between water and albite melts

    Institute of Scientific and Technical Information of China (English)

    SUN; Qiang; (孙樯); XIE; Hongsen; (谢鸿森); ZHENG; Haifei; (郑海飞); GUO; Jie; (郭捷); DING; Dongye,(丁东业)

    2002-01-01

    On the basis of FTIR and Raman spectra studies on hydrous albite glasses, it is found that there exist two water solubility mechanisms in albite melts simultaneously. On the one hand, water interacts with Al -O°-Al to produce the Q3 Al-OH, leading to depolymerization, and this results in the appearance of 4500 cm(1 in FTIR spectra and 900 cm(1 in Raman spectra. On the other hand, the exchange of H+ in water with Na+ in albite melt as charge-balancing cation occurs at the same time. In the initial stage, the production of Al -OH is the dominant solubility mechanism, at the stage of higher water contents, the exchange of H+ with Na+ becomes the important dissolution mechanism. The dissolution of water into albite melt can be expressed as H2O+ 3NaAlSi3O8 = 2NaAl(OH)Si3O7.5 +HAlSi3O8 +NaOH.

  2. Kaonic atoms – studies of the strong interaction with strangeness

    Directory of Open Access Journals (Sweden)

    Marton J.

    2014-01-01

    Full Text Available The strong interaction of charged antikaons (K− with nucleons and nuclei in the low-energy regime is a fascinating topic. The antikaon plays a peculiar role in hadron physics due to the strong attraction antikaon-nucleon which is a key question for possible kaonic nuclear bound states. A rather direct experimental access to the antikaon-nucleon scattering lengths is provided by precision X-ray spectroscopy of transitions to low-lying states in light kaonic atoms like kaonic hydrogen and deuterium. After the successful completion of precision measurements on kaonic hydrogen and helium isotopes by SIDDHARTA at DAΦNE/LNF, new X-ray studies with the focus on kaonic deuterium are in preparation (SIDDHARTA2. In the future with kaonic deuterium data the antikaon-nucleon isospin-dependent scattering lengths can be extracted for the first time. An overview of the experimental results of SIDDHARTA and an outlook to future perspectives in the SIDDHARTA2 experiments in this frontier research field will be given.

  3. Interactive flutter analysis and parametric study for conceptual wing design

    Science.gov (United States)

    Mukhopadhyay, Vivek

    1995-01-01

    An interactive computer program was developed for wing flutter analysis in the conceptual design stage. The objective was to estimate the flutter instability boundary of a flexible cantilever wing, when well defined structural and aerodynamic data are not available, and then study the effect of change in Mach number, dynamic pressure, torsional frequency, sweep, mass ratio, aspect ratio, taper ratio, center of gravity, and pitch inertia, to guide the development of the concept. The software was developed on MathCad (trademark) platform for Macintosh, with integrated documentation, graphics, database and symbolic mathematics. The analysis method was based on nondimensional parametric plots of two primary flutter parameters, namely Regier number and Flutter number, with normalization factors based on torsional stiffness, sweep, mass ratio, aspect ratio, center of gravity location and pitch inertia radius of gyration. The plots were compiled in a Vaught Corporation report from a vast database of past experiments and wind tunnel tests. The computer program was utilized for flutter analysis of the outer wing of a Blended Wing Body concept, proposed by McDonnell Douglas Corporation. Using a set of assumed data, preliminary flutter boundary and flutter dynamic pressure variation with altitude, Mach number and torsional stiffness were determined.

  4. A study of the flow-leaflet interaction

    Science.gov (United States)

    Ledesma, R.; Zenit, R.; Pulos, G.

    2008-11-01

    The manufacture of prosthetic heart valves is a relatively simple process. Valves made with biomaterials simply copy the ``design'' of the original ones, because of the limited understanding of the physical mechanism involved in the proper performance of valves. The identification of the parameters that determine the valve performance will help to improve the prosthetic designs and to minimize the health complications. In this work we study the flow-leaflet interaction in a pulsating flow, with the purpose of evaluating the influence of the material properties and leaflet dimensions. A 2D flow channel was design to obtain measurements of the leaflet deflection, for different flow conditions. Using a PIV system, measurements of the flow velocity fields are also obtained. Preliminary results show that the deflection of the leaflet and the proper open-close cycle, that determines the valve performance, is directly related to the leaflet length, thickness and material properties. We have identified the range of parameters for which the valve performance is acceptable.

  5. Busbar studies for the LHC interaction region quadrupoles

    CERN Document Server

    Bauer, P; Fehér, S; Kerby, J S; Lamm, M J; Orris, D; Sylvester, C D; Tompkins, J C; Zlobin, A V

    2001-01-01

    Fermilab (FNAL) and the Japanese high energy physics lab (KEK) are developing the superconducting quadrupole magnets for the interaction regions (IR) of the Large Hadron Collider (LHC). These magnets have a nominal field gradient of 215 T/m in a 70 mm bore and operate in superfluid helium at 1.9 K. The IR magnets are electrically interconnected with superconducting busbars, which need to be protected in the event of a quench. Experiments to determine the most suitable busbar design for the LHC IR magnets and the analysis of the data are presented. The main purpose of the study was to find a design that allows the inclusion of the superconducting busbars in the magnet quench protection scheme, thus avoiding additional quench protection circuitry. A proposed busbar design that was tested in these experiments consists of a superconducting cable, which is normally used for the inner layer of the Fermilab IR quadrupoles, soldered to similar Rutherford type cables as a stabilizer. A series of prototypes with varyin...

  6. A Numerical Study on Wave-Mud Interaction

    Institute of Scientific and Technical Information of China (English)

    ZHANG Dao-hua; NG Chiu-on

    2006-01-01

    Presented in this paper is a numerical study on the interaction of progressive waves propagating in a body of water overlying a layer of viscous fluid mud on the bottom, with emphasis placed on the induced oscillatory motion of the water-mud interface. The fully nonlinear Navier-Stokes equations with the complete set of viscous boundary conditions are solved numerically by a finite difference method that is based on a time-dependent boundary-fitted curvilinear coordinate system, for the simulation of wave motion in the two-layer viscous fluid system. Waves of moderate wavelength are generated in the upper water layer by a numerical flap-type wavemaker. The dynamic pressure due to the surface wave is transmitted downward onto the lower layer, generating wave motion on the interface. On mimicking some reported experimental conditions, the ratio of interfacial to surface wave amplitudes is evaluated and the results are found to compare more favorably with the experimental data than the prediction by a linear theory.

  7. Experimental beam system studies of plasma-polymer interactions

    Science.gov (United States)

    Nest, Dustin George

    Since the invention of the integrated circuit, the semiconductor industry has relied on the shrinking of device dimensions to increase device performance and decrease manufacturing costs. However, the high degree of roughening observed during plasma etching of current generation photoresist (PR) polymers can result in poor pattern transfer and ultimately decreased device performance or failure. Plasma-surface interactions are inherently difficult to study due to the highly coupled nature of the plasma enviroment. To better understand these interactions, a beam system approach is employed where polymers are exposed to beams of ions and vacuum ultraviolet (VUV) photons. Through the use of the beam system approach, simultaneous VUV radiation, ion bombardment, and moderate substrate heating have been identified as key elements, acting synergistically, as being responsible for roughening of current generation 193 nm PR during plasma processing. Sequential exposure is not adequate for the development of surface roughness, as observed through AFM and SEM. Ion bombardment results in the formation of a graphitized near-surface region with a depth of a few nanometers, the expected ion penetration depth of 150 eV argon ions. In contrast, VUV radiation results in the loss of carbon-oxygen bonds in the bulk PR as observed through Transmission FTIR. Based on the differing penetration depth of either ions or photons, their resulting chemical modifications, and the temperature dependence of the observed roughening, a mechanism is proposed based on stress relaxation resulting in surface buckling. The surface roughness of poly(4-methyl styrene) (P4MS) and poly(alpha-methyl styrene) (PalphaMS) have also been investigated under exposure to ions and VUV photons. PaMS degrades during VUV radiation above its ceiling temperature of ˜60°C. Despite having the same chemical composition as PalphaMS, P4MS does not degrade during VUV exposure at 70°C due to its relatively high ceiling

  8. Association of interleukin genes polymorphism with asthma susceptibility in Indian children: a case-control study.

    Science.gov (United States)

    Dixit, Pratibha; Awasthi, Shally; Agarwal, Sarita

    2015-01-01

    Interleukins (IL) 4 and 13 genes and their receptors (R) are the key cytokines which amplify inflammatory reactions in asthma. This study aimed to investigate the association of IL 4, 4 R, 13 and 13 R genes polymorphism with asthma in Indian children. In this hospital-based case-control study, included were children aged 1-15 years recruited as diagnosed cases of bronchial asthma, according to EPR 2007 and excluded were subjects with other respiratory diseases. Children with no present or past history of asthma were enrolled as controls. Spirometry was done in cases age ≥ 6 years. Gene-gene interaction was evaluated using binary logistic regression. From October 2010 to July 2013, 275 cases and 275 controls were recruited. Gene-gene interactions between C1112T in IL 13 and Ile50Val in IL 4 R gene polymorphisms were found to be statistically significant (OR = 2.37, 95% CI = 1.04-5.42, p = 0.040). Individuals with CT and GG genotype of C1112T in IL 13 and Ile50Val in IL 4 R were at twice the risk for the development of asthma compared to individuals with both non-risk genotypes. The data suggests that gene-gene interactions between IL 13 and IL 4 R genes may play an important role in asthma among Indian children.

  9. The Electron-Phonon Interaction as Studied by Photoelectron Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    D.W. Lynch

    2004-09-30

    With recent advances in energy and angle resolution, the effects of electron-phonon interactions are manifest in many valence-band photoelectron spectra (PES) for states near the Fermi level in metals.

  10. A Study of Feature Interactions in Intelligent Networks

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    @@ Plain Old Telephone Services (POTS) are used to establish the voice connection between two telephone users; and supplementary services such as call waiting, call forwarding, and call completion to busy subscribers, provide additional functions to POTS. In order to facilitate the communication between users, telecommunication networks should provide new services to end users in a quick way. However, the introduction of new telecommunication services into the existing network may interfere with the existing services, thus causing feature interactions. In many cases, feature interactions bring the unwanted or undesired system behavior to end users, decreasing the service quality. Although new technology like Intelligent Networks (IN) enables the quick introduction of new telecommunication services, but owing to the feature interaction, and the vast effort has to be put into checking the compatibility between telecommunication services. Feature interactions has become the bottle-neck problem to the development of new telecommunication services.

  11. A Brief Study Of The Interactive-oriented Language Teaching

    Institute of Scientific and Technical Information of China (English)

    徐海仙

    2015-01-01

    In an interaction-oriented classroom, the teacher's role undergoes a significant shift from a knowledge giver to a facilitator and helper, while students' role changes from a passive one into an activeone.

  12. Framework to study dynamic dependencies in networks of interacting processes.

    Science.gov (United States)

    Chicharro, Daniel; Ledberg, Anders

    2012-10-01

    The analysis of dynamic dependencies in complex systems such as the brain helps to understand how emerging properties arise from interactions. Here we propose an information-theoretic framework to analyze the dynamic dependencies in multivariate time-evolving systems. This framework constitutes a fully multivariate extension and unification of previous approaches based on bivariate or conditional mutual information and Granger causality or transfer entropy. We define multi-information measures that allow us to study the global statistical structure of the system as a whole, the total dependence between subsystems, and the temporal statistical structure of each subsystem. We develop a stationary and a nonstationary formulation of the framework. We then examine different decompositions of these multi-information measures. The transfer entropy naturally appears as a term in some of these decompositions. This allows us to examine its properties not as an isolated measure of interdependence but in the context of the complete framework. More generally we use causal graphs to study the specificity and sensitivity of all the measures appearing in these decompositions to different sources of statistical dependence arising from the causal connections between the subsystems. We illustrate that there is no straightforward relation between the strength of specific connections and specific terms in the decompositions. Furthermore, causal and noncausal statistical dependencies are not separable. In particular, the transfer entropy can be nonmonotonic in dependence on the connectivity strength between subsystems and is also sensitive to internal changes of the subsystems, so it should not be interpreted as a measure of connectivity strength. Altogether, in comparison to an analysis based on single isolated measures of interdependence, this framework is more powerful to analyze emergent properties in multivariate systems and to characterize functionally relevant changes in the

  13. Synthetic Polymer Nanoparticle-Polysaccharide Interactions: A Systematic Study

    OpenAIRE

    Zeng, Zhiyang; Patel, Jiten; Lee, Shih-Hui; McCallum, Monica; Tyagi, Anuradha; Yan, Mingdi; Shea, Kenneth J.

    2012-01-01

    The interaction between synthetic polymer nanoparticles (NPs) and biomacromolecules (e.g. proteins, lipids and polysaccharides) can profoundly influence the NPs fate and function. Polysaccharides (e.g. heparin/heparin sulfate) are a key component of cell surfaces and the extracelluar matrix and play critical roles in many biological processes. We report a systematic investigation of the interaction between synthetic polymer nanoparticles and polysaccharides by ITC, SPR and an anticoagulant as...

  14. Studying epigenetic interactions using MicroScale Thermophoresis (MST

    Directory of Open Access Journals (Sweden)

    Thomas Schubert

    2015-08-01

    Full Text Available Epigenetic regulation is based on specific molecular interactions between epigenetic reader, writer and eraser molecules and chromatin. Binding parameters of these interactions such as binding affinities, stoichiometries and thermodynamics are essential for the understanding of the establishment and maintenance of epigenetic networks. The MicroScale Thermophoresis (MST is a rapid and precise method to characterize epigenetic interactions in solution at microliter scale, requiring low concentrations of the potential interactors. The technology is based on the movement of molecules through temperature gradients, a physical effect referred to as thermophoresis. The thermophoretic movement of a molecule depends on its size, charge and hydration shell. Upon the interaction of two molecules, at least one of these parameters is altered, leading to a change in the movement behavior, which can be used to quantify molecular interactions. MST offers free choice of buffers, also allowing measurements in serum and crude extracts, thereby ensuring optimal reaction conditions. Binding affinities from pM to mM can be measured, perfectly suited to analyze protein/protein, protein/modified peptide and protein/nucleic acid interactions in epigenetics. This review demonstrates the potential of this rapid and versatile technology in the characterization of epigenetic modifiers.

  15. Yakima River Species Interactions Studies, Annual Report 2000.

    Energy Technology Data Exchange (ETDEWEB)

    Pearsons, Todd N.

    2001-12-01

    Species interactions research and monitoring was initiated in 1989 to investigate ecological interactions among fish in response to proposed supplementation of salmon and steelhead in the upper Yakima River basin. This is the ninth of a series of progress reports that address species interactions research and supplementation monitoring of fishes in the Yakima River basin. Data have been collected prior to supplementation to characterize the ecology and demographics of non-target taxa (NTT) and target taxon, and develop methods to monitor interactions and supplementation success. Major topics of this report are associated with the chronology of ecological interactions that occur throughout a supplementation program, implementing NTT monitoring prescriptions for detecting potential impacts of hatchery supplementation, hatchery fish interactions, and monitoring fish predation indices. This report is organized into four chapters, with a general introduction preceding the first chapter. This annual report summarizes data collected primarily by the Washington Department of Fish and Wildlife (WDFW) between January 1, 2000 and December 31, 2000 in the Yakima basin, however these data were compared to data from previous years to identify preliminary trends and patterns. Summaries of each of the chapters included in this report are described.

  16. Yakima River Species Interactions Studies, Annual Report 1994.

    Energy Technology Data Exchange (ETDEWEB)

    Pearsons, Todd N.

    1996-09-01

    Species interactions research was initiated in 1989 to investigate ecological interactions among fish in response to proposed supplementation of salmon and steelhead in the upper Yakima River basin. This is the fifth of a series of annual reports that address species interactions research and pre-facility monitoring of fishes in the upper Yakima River basin. Data have been collected prior to supplementation to characterize the rainbow trout and other fish populations such as steelhead and spring chinook salmon, predict the potential interactions that may occur as a result of supplementation, and develop methods to monitor interactions. Major topics of this report are associated with the life history of rainbow trout, interactions experimentation, and methods for sampling. This report is organized into two chapters followed by seven ''updates'' with a general introduction preceding the first chapter and a general discussion following the last update. An appendix follows the general discussion. This annual report summarizes data collected primarily by the Washington Department of Fish and Wildlife (WDFW) between January 1 and December 31, 1994 in the upper Yakima basin above Roza Dam, however these data were compared to data from previous years to identify preliminary trends and patterns. Major preliminary findings from each of the chapters included in this report are described.

  17. Preliminary experimental study of liquid lithium water interaction

    Energy Technology Data Exchange (ETDEWEB)

    You, X.M.; Tong, L.L.; Cao, X.W., E-mail: caoxuewu@sjtu.edu.cn

    2015-10-15

    Highlights: • Explosive reaction occurs when lithium temperature is over 300 °C. • The violence of liquid lithium water interaction increases with the initial temperature of liquid lithium. • The interaction is suppressed when the initial water temperature is above 70 °C. • Steam explosion is not ignorable in the risk assessment of liquid lithium water interaction. • Explosion strength of liquid lithium water interaction is evaluated by explosive yield. - Abstract: Liquid lithium is the best candidate for a material with low Z and low activation, and is one of the important choices for plasma facing materials in magnetic fusion devices. However, liquid lithium reacts violently with water under the conditions of loss of coolant accidents. The release of large heats and hydrogen could result in the dramatic increase of temperature and pressure. The lithium–water explosion has large effect on the safety of fusion devices, which is an important content for the safety assessment of fusion devices. As a preliminary investigation of liquid lithium water interaction, the test facility has been built and experiments have been conducted under different conditions. The initial temperature of lithium droplet ranged from 200 °C to 600 °C and water temperature was varied between 20 °C and 90 °C. Lithium droplets were released into the test section with excess water. The shape of lithium droplet and steam generated around the lithium were observed by the high speed camera. At the same time, the pressure and temperature in the test section were recorded during the violent interactions. The preliminary experimental results indicate that the initial temperature of lithium and water has an effect on the violence of liquid lithium water interaction.

  18. Multilocus interactions at maternal tumor necrosis factor-α, tumor necrosis factor recptors, interleukin-6 and interleukin-6 receptor genes predict spontaneous preterm labor in European-American women

    DEFF Research Database (Denmark)

    Menon, Ramkumar; Velez, Digna R.; Simhan, Hyagriv

    2006-01-01

    -American women. In this study we examine the allelic and genotypic variations and the gene-gene interactions in the TNF-a, TNFRs, IL-6, and IL-6R genes in maternal DNA samples by using a case-control model. Study design: Maternal DNA from cases of sPTB after preterm labor (n = 101) and controls (normal term...... labor and delivery) (n = 321) were genotyped for SNPs in the TNF-a (6), TNFRI (6), TNFRII (7), IL-6 (5), and IL-6R (3) loci. SNPs were tested for both allele and genotype differences (cases vs controls) with the use of standard genetic epidemiologic methods. Multilocus interaction was assessed...

  19. Computational Study of Flow Interactions in Coaxial Rotors

    Science.gov (United States)

    Yoon, Seokkwan; Lee, Henry C.; Pulliam, Thomas H.

    2016-01-01

    account for multiple real-world constraints up front in design nor possible to know what performance is possible with a given design. Since unmanned vehicles are sized and optimized for the particular mission, a modern low-fidelity conceptual design and sizing tool that has been used for the design of large helicopters can be used for design of small coaxial rotorcraft. However, unlike most helicopters with single main rotor, the interactions between the upper and lower rotors emerge as an important factor to consider in design because an increase in performance of a multi-rotor system is not proportional to the number of rotors. Interference losses and differences in thrusts between the upper and lower rotors were investigated by theoretical methods as well as a computational fluid dynamics (CFD) method using the Reynolds-Averaged Navier-Stokes (RANS) equations. In this work, hybrid turbulence models are used to investigate the physics of interactions between coaxial rotors and a fuselage that are not well understood. Present study covers not only small-scale drones but also large-scale coaxial rotors for heavy-lifting missions. Considering the recently proposed FAA drone rules that require the flight only in visual line-of-sight, a large multirotor might be used as an airborne carrier for launch and recovery of unmanned aircraft systems with a human operator onboard. For applications to civil operations, their aerodynamic performance and noise levels need to be assessed. Noise is one of the largest limiting factors to rotorcraft operations in urban area. Since the high-frequency noise of multi-rotors may increase the annoyance, noise may turn out to be a key issue that must be addressed for market acceptability. One of the objectives of the present work is to study the effects of inter-rotor spacing and collectives on the performance, efficiency, and acoustics of coaxial rotor systems.

  20. Using Neutrons to Study Fluid-Rock Interactions in Shales

    Science.gov (United States)

    DiStefano, V. H.; McFarlane, J.; Anovitz, L. M.; Gordon, A.; Hale, R. E.; Hunt, R. D.; Lewis, S. A., Sr.; Littrell, K. C.; Stack, A. G.; Chipera, S.; Perfect, E.; Bilheux, H.; Kolbus, L. M.; Bingham, P. R.

    2015-12-01

    Recovery of hydrocarbons by hydraulic fracturing depends on complex fluid-rock interactions that we are beginning to understand using neutron imaging and scattering techniques. Organic matter is often thought to comprise the majority of porosity in a shale. In this study, correlations between the type of organic matter embedded in a shale and porosity were investigated experimentally. Selected shale cores from the Eagle Ford and Marcellus formations were subjected to pyrolysis-gas chromatography, Differential Thermal Analysis/Thermogravimetric analysis, and organic solvent extraction with the resulting affluent analyzed by gas chromatography-mass spectrometry. The pore size distribution of the microporosity (~1 nm to 2 µm) in the Eagle Ford shales was measured before and after solvent extraction using small angle neutron scattering. Organics representing mass fractions of between 0.1 to 1 wt.% were removed from the shales and porosity generally increased across the examined microporosity range, particularly at larger pore sizes, approximately 50 nm to 2 μm. This range reflects extraction of accessible organic material, including remaining gas molecules, bitumen, and kerogen derivatives, indicating where the larger amount of organic matter in shale is stored. An increase in porosity at smaller pore sizes, ~1-3 nm, was also present and could be indicative of extraction of organic material stored in the inter-particle spaces of clays. Additionally, a decrease in porosity after extraction for a sample was attributed to swelling of pores with solvent uptake. This occurred in a shale with high clay content and low thermal maturity. The extracted hydrocarbons were primarily paraffinic, although some breakdown of larger aromatic compounds was observed in toluene extractions. The amount of hydrocarbon extracted and an overall increase in porosity appeared to be primarily correlated with the clay percentage in the shale. This study complements fluid transport neutron

  1. Experimental study of cadmium interaction with periphytic biofilms

    Energy Technology Data Exchange (ETDEWEB)

    Pokrovsky, O.S., E-mail: oleg@lmtg.obs-mip.fr [Geochimie et Biogeochimie Experimentale, UMR 5563, CNRS-OMP-Universite Toulouse, 14 Avenue Edouard Belin, 31400 Toulouse (France); Feurtet-Mazel, A. [Universite de Bordeaux 1, CNRS, UMR 5805 EPOC, Place du Dr Peyneau, 33120 Arcachon (France); Martinez, R.E. [Center for Applied Geosciences, Universitat Tuebingen, Sigwartstrasse 10, Tuebingen 72076 (Germany); Morin, S. [Unite de Recherche Reseaux, Epuration et Qualite des Eaux REQE, Cemagref, 50 Avenue de Verdun, F-33612 Cestas Cedex (France); Baudrimont, M. [Universite de Bordeaux 1, CNRS, UMR 5805 EPOC, Place du Dr Peyneau, 33120 Arcachon (France); Duong, T. [Universite de Bordeaux 1, CNRS, UMR 5805 EPOC, Place du Dr Peyneau, 33120 Arcachon (France)] [Institute of Environmental Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay, Hanoi (Viet Nam); Coste, M. [Unite de Recherche Reseaux, Epuration et Qualite des Eaux REQE, Cemagref, 50 Avenue de Verdun, F-33612 Cestas Cedex (France)

    2010-03-15

    This study addresses the interaction of Cd with natural biofilms of periphytic diatoms grown during different seasons in metal-contaminated and metal-non-contaminated streams, along a tributary of the Lot River, France. Specifically, it aims to test whether the biofilms from contaminated sites have developed a protective mechanism due to high Cd exposure. Towards this goal, reversible adsorption experiments on untreated biofilms were performed in 0.01 M NaNO{sub 3} with a pH ranging from 2 to 8, Cd concentration from 0.5 to 10,000 {mu}g/L and exposure time from 1 to 24 h. Two types of experiments, pH-dependent adsorption edge and constant-pH 'Langmuirian'-type isotherms were conducted. Results were adequately modeled using a Linear Programming Model. It was found that the adsorption capacities of natural biofilm consortia with respect to Cd do not depend on season and are not directly linked to the growth environment. The biofilms grown in non-contaminated (4.6 ppb Cd in solid) and contaminated (570 ppb Cd in solid) settings exhibit similar adsorption capacities in the Cd concentration range in solution of 100-10,000 {mu}g/L but quite different capacities at low Cd concentration (0.5-100 {mu}g/L); unexpectedly, the non-contaminated biofilm adsorbs approximately 10 times more Cd than the contaminated one. It is therefore possible that the strong low-abundant ligands (for example, phosphoryl or sulfhydryls) are already metal-saturated on surfaces of biofilm grown in the contaminated site whereas these sites are still available for metal adsorption in samples grown in non-contaminated sites.

  2. Interactions between imazethapyr and bovine serum albumin: Spectrofluorimetric study

    Energy Technology Data Exchange (ETDEWEB)

    Pacheco, Maria E. [Division Quimica Analitica, Departamento de Quimica, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Buenos Aires (Argentina); Bruzzone, Liliana, E-mail: bruzzone@quimica.unlp.edu.ar [Division Quimica Analitica, Departamento de Quimica, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Buenos Aires (Argentina)

    2012-10-15

    The interaction between imazethapyr (IMA) and bovine serum albumin (BSA) was investigated by fluorescence spectroscopy. The Stern-Volmer quenching constant (K{sub SV}) at three temperatures was evaluated in order to determine the quenching mechanism. The dependence of fluorescence quenching on viscosity was also evaluated for this purpose. The results showed that IMA quenches the fluorescence intensity of BSA through a static quenching process. The values of the binding constant for the formed BSA-IMA complex and the number of binding sites were found to be 1.51 Multiplication-Sign 10{sup 5} M{sup -1} and 0.77, respectively, at room temperature. Based on the calculated thermodynamic parameters, the forces that dominate the binding process are hydrogen bonds and van der Waals forces, and the binding process is spontaneous and exothermic. The quenching of protein fluorescence by iodide ion was used to probe the accessibility of tryptophan residues in BSA and the change in accessibility induced by the presence of IMA. According to the obtained results, the BSA-IMA complex is formed in the site where the Trp-134 is located, causing it to become less exposed to the solvent. - Highlights: Black-Right-Pointing-Pointer Fluorescence spectroscopy helps to understand protein binding mechanisms. Black-Right-Pointing-Pointer Quenching measurements reveal the nature of the binding process involved. Black-Right-Pointing-Pointer Iodine ion can be used to study the change in accessibility of tryptophan residues. Black-Right-Pointing-Pointer Thermodynamic parameters for the binding reaction confirm binding modes.

  3. Microfluidic Experiments Studying Pore Scale Interactions of Microbes and Geochemistry

    Science.gov (United States)

    Chen, M.; Kocar, B. D.

    2016-12-01

    Understanding how physical phenomena, chemical reactions, and microbial behavior interact at the pore-scale is crucial to understanding larger scale trends in groundwater chemistry. Recent studies illustrate the utility of microfluidic devices for illuminating pore-scale physical-biogeochemical processes and their control(s) on the cycling of iron, uranium, and other important elements 1-3. These experimental systems are ideal for examining geochemical reactions mediated by microbes, which include processes governed by complex biological phenomenon (e.g. biofilm formation, etc.)4. We present results of microfluidic experiments using a model metal reducing bacteria and varying pore geometries, exploring the limitations of the microorganisms' ability to access tight pore spaces, and examining coupled biogeochemical-physical controls on the cycling of redox sensitive metals. Experimental results will provide an enhanced understanding of coupled physical-biogeochemical processes transpiring at the pore-scale, and will constrain and compliment continuum models used to predict and describe the subsurface cycling of redox-sensitive elements5. 1. Vrionis, H. A. et al. Microbiological and geochemical heterogeneity in an in situ uranium bioremediation field site. Appl. Environ. Microbiol. 71, 6308-6318 (2005). 2. Pearce, C. I. et al. Pore-scale characterization of biogeochemical controls on iron and uranium speciation under flow conditions. Environ. Sci. Technol. 46, 7992-8000 (2012). 3. Zhang, C., Liu, C. & Shi, Z. Micromodel investigation of transport effect on the kinetics of reductive dissolution of hematite. Environ. Sci. Technol. 47, 4131-4139 (2013). 4. Ginn, T. R. et al. Processes in microbial transport in the natural subsurface. Adv. Water Resour. 25, 1017-1042 (2002). 5. Scheibe, T. D. et al. Coupling a genome-scale metabolic model with a reactive transport model to describe in situ uranium bioremediation. Microb. Biotechnol. 2, 274-286 (2009).

  4. Synthetic polymer nanoparticle-polysaccharide interactions: a systematic study.

    Science.gov (United States)

    Zeng, Zhiyang; Patel, Jiten; Lee, Shih-Hui; McCallum, Monica; Tyagi, Anuradha; Yan, Mingdi; Shea, Kenneth J

    2012-02-08

    The interaction between synthetic polymer nanoparticles (NPs) and biomacromolecules (e.g., proteins, lipids, and polysaccharides) can profoundly influence the NPs fate and function. Polysaccharides (e.g., heparin/heparin sulfate) are a key component of cell surfaces and the extracelluar matrix and play critical roles in many biological processes. We report a systematic investigation of the interaction between synthetic polymer nanoparticles and polysaccharides by ITC, SPR, and an anticoagulant assay to provide guidelines to engineer nanoparticles for biomedical applications. The interaction between acrylamide nanoparticles (~30 nm) and heparin is mainly enthalpy driven with submicromolar affinity. Hydrogen bonding, ionic interactions, and dehydration of polar groups are identified to be key contributions to the affinity. It has been found that high charge density and cross-linking of the NP can contribute to high affinity. The affinity and binding capacity of heparin can be significantly diminished by an increase in salt concentration while only slightly decreased with an increase of temperature. A striking difference in binding thermodynamics has been observed when the main component of a polymer nanoparticle is changed from acrylamide (enthalpy driven) to N-isopropylacryalmide (entropy driven). This change in thermodynamics leads to different responses of these two types of polymer NPs to salt concentration and temperature. Select synthetic polymer nanoparticles have also been shown to inhibit protein-heparin interactions and thus offer the potential for therapeutic applications.

  5. A numerical study of two interacting coronal mass ejections

    Directory of Open Access Journals (Sweden)

    J. M. Schmidt

    2004-06-01

    Full Text Available The interaction in the solar wind between two coronal mass ejections (CMEs is investigated using numerical simulations. We show that the nature of the interaction depends on whether the CME magnetic structures interact, but in all cases the result is an equilisation of the speed of the two CMEs. In the absence of magnetic interaction, the forward shock of the faster trailing CME interacts with the slow leading CME, and accelerates it. When the two CMEs have magnetic fields with the same sense of rotation, magnetic reconnection occurs between the two CMEs, leading to the formation of a single magnetic structure: in the most extreme cases, one CME "eats" the other. When the senses of rotation are opposite, reconnection does not occur, but the CMEs collide in a highly non-elastic manner, again forming a single structure. The possibility of enhanced particle acceleration in such processes is assessed. The presence of strong magnetic reconnection provides excellent opportunities for the acceleration of thermal particles, which then form a seed population for further acceleration at the CME shocks. The presence of a large population of seed particles will thus lead to an overall increase in energetic particle fluxes, as suggested by some observations.

  6. A numerical study of interactions and stellar bars

    Science.gov (United States)

    Martinez-Valpuesta, Inma; Aguerri, J. Alfonso L.; González-García, A. César; Dalla Vecchia, Claudio; Stringer, Martin

    2017-01-01

    For several decades, it has been known that stellar bars in disc galaxies can be triggered by interactions, or by internal processes such as dynamical instabilities. In this work, we explore the differences between these two mechanisms using numerical simulations. We perform two groups of simulations based on isolated galaxies, one group in which a bar develops naturally, and another group in which the bar could not develop in isolation. The rest of the simulations recreate 1:1 coplanar fly-by interactions computed with the impulse approximation. The orbits we use for the interactions represent the fly-bys in groups or clusters of different masses accordingly to the velocity of the encounter. In the analysis, we focus on bars' amplitude, size, pattern speed and their rotation parameter, R=R_{CR}/R_{bar}. The latter is used to define fast (R1.4). Compared with equivalent isolated galaxies, we find that bars affected or triggered by interactions: (i) remain in the slow regime for longer, (ii) are more boxy in face-on views and (iii) they host kinematically hotter discs. Within this set of simulations, we do not see strong differences between retrograde or prograde fly-bys. We also show that slow interactions can trigger bar formation.

  7. COMPUTATIONAL METHODS FOR STUDYING THE INTERACTION BETWEEN POLYCYCLIC AROMATIC HYDROCARBONS AND BIOLOGICAL MACROMOLECULES

    Science.gov (United States)

    Computational Methods for Studying the Interaction between Polycyclic Aromatic Hydrocarbons and Biological Macromolecules .The mechanisms for the processes that result in significant biological activity of PAHs depend on the interaction of these molecules or their metabol...

  8. Studies of final state interactions via femtoscopy in ALICE

    CERN Document Server

    ,

    2016-01-01

    Femtoscopy is a technique enabling measurements of the space-time characteristics of particle-emitting sources. However, the femtoscopic analysis is also sensitive to the interaction cross-section. In this paper we show the first preliminary measurements of $\\rm K^0_SK^{\\pm}$ correlation functions in Pb-Pb collisions at $\\sqrt{s_{\\rm NN}}=5.02$ TeV. These correlations originate from the final-state interactions which proceed through the $a_0(980)$ resonance only and can be employed to constrain its parameters. A similar approach can be applied to baryon pairs to extract the unknown interaction cross-sections for some (anti-)baryon-(anti-)baryon pairs. We show baryon--baryon and baryon--anti-baryon correlation functions of protons and lambdas, as well as discuss shortly the fitting method.

  9. Detecting Genetic Interactions for Quantitative Traits Using m-Spacing Entropy Measure

    Directory of Open Access Journals (Sweden)

    Jaeyong Yee

    2015-01-01

    Full Text Available A number of statistical methods for detecting gene-gene interactions have been developed in genetic association studies with binary traits. However, many phenotype measures are intrinsically quantitative and categorizing continuous traits may not always be straightforward and meaningful. Association of gene-gene interactions with an observed distribution of such phenotypes needs to be investigated directly without categorization. Information gain based on entropy measure has previously been successful in identifying genetic associations with binary traits. We extend the usefulness of this information gain by proposing a nonparametric evaluation method of conditional entropy of a quantitative phenotype associated with a given genotype. Hence, the information gain can be obtained for any phenotype distribution. Because any functional form, such as Gaussian, is not assumed for the entire distribution of a trait or a given genotype, this method is expected to be robust enough to be applied to any phenotypic association data. Here, we show its use to successfully identify the main effect, as well as the genetic interactions, associated with a quantitative trait.

  10. Cross-Racial Interactions during College: A Longitudinal Study of Four Forms of Interracial Interactions among Elite White College Students

    Directory of Open Access Journals (Sweden)

    William Carson Byrd

    2014-06-01

    Full Text Available College and universities present distinct opportunities to interact across racial and ethnic lines that may influence people’s prejudice toward different groups. This study examines the influence of four forms of cross-race interaction on traditional and modern forms of racial prejudice among white college students at 28 of the most selective colleges and universities in the US. This study finds that, although white students’ level of racial prejudice declines over four years, interracial contact during college does not significantly influence their level of prejudice. Moreover, a race-related form of social identity is the most consistent influence on students’ racial prejudice.

  11. Studies of Positron Generation from Ultraintense Laser-Matter Interactions

    Science.gov (United States)

    Williams, Gerald Jackson

    Laser-produced pair jets possess unique characteristics that offer great potential for their use in laboratory-astrophysics experiments to study energetic phenomenon such as relativistic shock accelerations. High-flux, high-energy positron sources may also be used to study relativistic pair plasmas and useful as novel diagnostic tools for high energy density conditions. Copious amounts of positrons are produced with MeV energies from directly irradiating targets with ultraintense lasers where relativistic electrons, accelerated by the laser field, drive positron-electron pair production. Alternatively, laser wakefield accelerated electrons can produce pairs by the same mechanisms inside a secondary converter target. This dissertation describes a series of novel experiments that investigate the characteristics and scaling of pair production from ultraintense lasers, which are designed to establish a robust platform for laboratory-based relativistic pair plasmas. Results include a simple power-law scaling to estimate the effective positron yield for elemental targets for any Maxwellian electron source, typical of direct laser-target interactions. To facilitate these measurements, a solenoid electromagnetic coil was constructed to focus emitted particles, increasing the effective collection angle of the detector and enabling the investigation of pair production from thin targets and low-Z materials. Laser wakefield electron sources were also explored as a compact, high repetition rate platform for the production of high energy pairs with potential applications to the creation of charge-neutral relativistic pair plasmas. Plasma accelerators can produce low-divergence electron beams with energies approaching a GeV at Hz frequencies. It was found that, even for high-energy positrons, energy loss and scattering mechanisms in the target create a fundamental limit to the divergence and energy spectrum of the emitted positrons. The potential future application of laser

  12. Collagen-curcumin interaction - A physico-chemical study

    Indian Academy of Sciences (India)

    N Nishad Fathima; R Saranya Devi; K B Rekha; Aruna Dhathathreyan

    2009-07-01

    Curcumin is a widely used therapeutic agent with a wide spectrum of biological and physiological applications like wound healing and interacts with the skin protein, collagen. This work reports the effect of curcumin on various physico-chemical properties of collagen. The results suggest that significant changes in viscosity and surface tension occur on collagen interacting with curcumin. Secondary structure analysis using circular dichroism shows that curcumin does not alter the triple helical structure of collagen. Increasing concentration of curcumin resulted in aggregation of the protein. Further, curcumin imparts high level of thermal stability to collagen with shrinkage temperature of collagen increasing from 60 to 90°C.

  13. The role of personality in dyadic interaction: A psychophysiological study.

    Science.gov (United States)

    Salminen, Mikko; Henttonen, Pentti; Ravaja, Niklas

    2016-11-01

    Psychophysiological activity was recorded during development discussions of 44 manager-subordinate pairs to examine the effects of the Big Five personality traits Extraversion and Conscientiousness, and personality similarity during dyadic social interaction. Facial electromyography and frontal electroencephalography (EEG) asymmetry were collected continuously during the 30-min discussions. Different actor and partner effects and Actor×Partner interactions were observed. Matching levels of Extraversion led to higher periocular muscle activity, indicating positive valence emotional expressions. The results are discussed considering similarity attraction theories. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Studies of Interactions Between Nano-Objects and Polarized Light

    Science.gov (United States)

    Xie, Dan

    Optical studies of nano-objects that have dimensions 10--1000 nm have become a flourishing field of research. This special dimension category, connecting the smaller (molecular) world and the larger (cellular) world, have enabled these nano-objects to be widely utilized as novel optical tools in many fields. In addition to the extensive applications of nano objects, increasing efforts are also being put to better understand their interactions with light at a fundamental level. The work presented in this dissertation is part of such efforts, in which I selected three types of nano-objects and studied their optical properties both in theory and experiment. Second-harmonic and sum-frequency generations are among the most well-known nonlinear optical processes. Dielectric nanocrystals that are SHG- and SFG-active are favored tools in bioimaging. For a nanocrystal, its SHG/SFG intensity depends on the geometry of the light-particle system, i.e., the relationship between the nanocrystal orientation and the laser polarization. Using BaTiO 3 nanocrystals as an example, I carried out an in-depth, theoretical investigation of such dependence. Particularly, I studied the possibility of selectively maximizing the contrast between light signals from two or more nanocrystals by manipulating laser polarization. I will present a discussion on how the capacity of this selective illumination depends on the relative orientation between the two nanocrystals and the polarization of the excitation field. The optical responses of non-spherical plasmonic particles, being dynamic and complex, are only partially understood. Gold nanorods (AuNRs) are one of the most popular members in this nanoparticle family. They can produce two-photon luminescence (TPL) and amplify molecular events occurring at their surface. Both phenomena are known to be associated with surface plasmon resonances (SPR) of AuNRs, but details of the mechanisms are yet to be understood and quantified. I constructed a two

  15. Study of DNA interaction with cobalt ferrite nanoparticles.

    Science.gov (United States)

    Pershina, A G; Sazonov, A E; Novikov, D V; Knyazev, A S; Izaak, T I; Itin, V I; Naiden, E P; Magaeva, A A; Terechova, O G

    2011-03-01

    Interaction of cobalt ferrite nanopowder and nucleic acid was investigated. Superparamagnetic cobalt ferrite nanoparticles (6-12 nm) were prepared by mechanochemical synthesis. Structure of the nanopowder was characterized using X-ray diffraction. It was shown that cobalt ferrite nanoparticles were associated with ssDNA and dsDNA in Tris-buffer resulting in bionanocomposite formation with mass weight relation nanoparticles: DNA 1:(0.083 +/- 0.003) and 1:(0.075 +/- 0.003) respectively. The mechanism of interaction between a DNA and cobalt ferrite nanoparticles was considered basing on the whole set of obtained data: FTIR-spectroscopy, analyzing desorption of DNA from the surface of the particles while changing the chemical content of the medium, and on the modeling interaction of specific biomolecule fragments with surface of a inorganic material. It was supposed that the linkage was based on coordination interaction of the phosphate groups and oxygen atoms heterocyclic bases of DNA with metal ions on the particle surface. These data can be used to design specific magnetic DNA-nanoparticles hybrid structures.

  16. Studies of the dilepton emission from nucleon-nucleon interactions

    NARCIS (Netherlands)

    Bacelar, JCS; Fujiwara, M; Shima, T

    2002-01-01

    real- and virtual-photon emission during interactions between few-nucleon systems have been investigated at KVI with a 190 MeV proton beam. Here I will concentrate the discussion on the results of the virtual-photon emission for the proton-proton system and proton-deuteron capture. Predictions of a

  17. A numerical study of interactions and stellar bars

    CERN Document Server

    Martinez-Valpuesta, Inma; González-García, A César; Vecchia, Claudio Dalla; Stringer, Martin

    2016-01-01

    For several decades it has been known that stellar bars in disc galaxies can be triggered by interactions, or by internal processes such as dynamical instabilities. In this work, we explore the differences between these two mechanisms using numerical simulations. We perform two groups of simulations based on isolated galaxies, one group in which a bar develops naturally, and another group in which the bar could not develop in isolation. The rest of the simulations recreate 1:1 coplanar fly-by interactions computed with the impulse approximation. The orbits we use for the interactions represent the fly-bys in groups or clusters of different masses accordingly to the velocity of the encounter. In the analysis we focus on bars' amplitude, size, pattern speed and their rotation parameter, ${\\cal R}=R_{CR}/R_{bar}$. The latter is used to define fast (${\\cal R}1.4$). Compared with equivalent isolated galaxies we find that bars affected or triggered by interactions: (i) remain in the slow regime for longer; (ii) are...

  18. Interaction Effects in Cross-National Studies of Achievement.

    Science.gov (United States)

    Fletcher, Todd V.; Sabers, Darrell L.

    1995-01-01

    The Bateria Woodcock Psico-Educativa en Espanol was administered to urban children in grades 1, 3, 5, 8, and 11 in Spain, Puerto Rico, Mexico, Costa Rica, and Peru. Spain consistently ranked highest on all achievement clusters (subject areas). For the other countries, interactions of cluster by grade level preclude any interpretation of main…

  19. Computational study of shock interaction with a vortex ring

    Science.gov (United States)

    Ding, Z.; Hussaini, M. Y.; Erlebacher, G.; Krothapalli, A.

    2001-10-01

    The problem of shock interaction with a vortex ring is investigated within the framework of axisymmetric Euler equations solved numerically by a shock-fitted sixth-order compact difference scheme. The vortex ring, which is based on Lamb's formula, has an upstream circulation Γ=0.01 and its aspect ratio R lies in the range 8⩽R⩽100. The shock Mach number varies in the range 1.1⩽M1⩽1.8. The vortex ring/shock interaction results in the streamwise compression of the vortex core by a factor proportional to the ratio of the upstream and downstream mean velocity U1/U2, and the generation of a toroidal acoustic wave and entropy disturbances. The toroidal acoustic wave propagates and interacts with itself on the symmetry axis of the vortex ring. This self-interaction engenders high amplitude rarefaction/compression pressure peaks upstream/downstream of the transmitted vortex core. This results in a significant increase in centerline sound pressure levels, especially near the shock (due to the upstream movement of the rarefaction peak) and in the far downstream (due to the downstream movement of the compression peak). The magnitude of the compression peak increases nonlinearly with M1. For a given M1, vortex rings with smaller aspect ratios (R40) generate pressure disturbances whose amplitudes are roughly independent of R.

  20. Experimental Study on 308nm Laser Interaction with Materials

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A 10 J, 40 ns XeC1 laser interaction with LY12 aluminum and optical glass K9 targets is reported. The properties of laser-produced plasma (LPP) are analyzed. As a result, some parameters such as plasma ignition threshold and plasma plume expansion velocity are obtained. Also, Laser induced pulse on irradiated targets are given.

  1. Studies on Molecular Interaction in Ternary Liquid Mixtures

    Directory of Open Access Journals (Sweden)

    R. Uvarani

    2010-01-01

    Full Text Available Ultrasonic velocity, density and viscosity for the ternary liquid mixtures of cyclohexanone with 1-propanol and 1-butanol in carbon tetrachloride were measured at 303 K. The acoustical parameters and their excess values were calculated. The trends in the variation of these excess parameters were used to discuss the nature and strength of the interactions present between the component molecules.

  2. Yakima River Species Interactions Studies, Annual Report 2001.

    Energy Technology Data Exchange (ETDEWEB)

    Pearsons, Todd N.

    2002-05-01

    Species interactions research and monitoring was initiated in 1989 to investigate ecological interactions among fish in response to proposed supplementation of salmon and steelhead in the upper Yakima River basin. This is the tenth of a series of progress reports that address species interactions research and supplementation monitoring of fishes in the Yakima River basin. Data have been collected before and during supplementation to characterize the ecology and demographics of non-target taxa (NTT) and target taxon, and to monitor interactions and supplementation success. Major topics of this report are associated with implementing NTT monitoring prescriptions for detecting potential impacts of hatchery supplementation, and monitoring fish predation indices. This report is organized into two chapters, with a general introduction preceding the first chapter. This annual report summarizes data collected primarily by the Washington Department of Fish and Wildlife (WDFW) between January 1, 2001 and December 31, 2001 in the Yakima basin, however these data were compared to data from previous years to identify preliminary trends and patterns.

  3. Studies of the dilepton emission from nucleon-nucleon interactions

    NARCIS (Netherlands)

    Bacelar, JCS; Fujiwara, M; Shima, T

    2002-01-01

    real- and virtual-photon emission during interactions between few-nucleon systems have been investigated at KVI with a 190 MeV proton beam. Here I will concentrate the discussion on the results of the virtual-photon emission for the proton-proton system and proton-deuteron capture. Predictions of a

  4. Interaction between Protein, Phytate, and Microbial Phytase. In Vitro Studies

    NARCIS (Netherlands)

    Kies, A.K.; Jonge, de L.H.; Kemme, P.A.; Jongbloed, A.W.

    2006-01-01

    The interaction between protein and phytate was investigated in vitro using proteins extracted from five common feedstuffs and from casein. The appearance of naturally present soluble protein-phytate complexes in the feedstuffs, the formation of complexes at different pHs, and the degradation of the

  5. Studying protein-protein interactions using peptide arrays

    NARCIS (Netherlands)

    Katz, C.; Levy-Beladev, L.; Rotem-Bamberger, S.; Rito, T.; Rudiger, S.G.D.; Friedler, A.

    2010-01-01

    Screening of arrays and libraries of compounds is well-established as a high-throughput method for detecting and analyzing interactions in both biological and chemical systems. Arrays and libraries can be composed from various types of molecules, ranging from small organic compounds to DNA, proteins

  6. Studying RNA-protein interactions in vivo by RNA immunoprecipitation

    DEFF Research Database (Denmark)

    Selth, Luke A; Close, Pierre; Svejstrup, Jesper Q

    2011-01-01

    The crucial roles played by RNA-binding proteins in all aspects of RNA metabolism, particularly in the regulation of transcription, have become increasingly evident. Moreover, other factors that do not directly interact with RNA molecules can nevertheless function proximally to RNA polymerases an...

  7. Interactive television revisited: a case study in home economics

    African Journals Online (AJOL)

    ISSN 0378-5254 Journal of Family Ecology and Consumer Sciences, Vol 28, 2000. 17 considered for the ... themselves into each other's shoes, try to perceive the world as the ... To encourage interactivity one needs to design very carefully in ...

  8. Yakima River Species Interactions Studies, Annual Report 1998.

    Energy Technology Data Exchange (ETDEWEB)

    Pearsons, Todd N.

    1999-12-01

    Species interactions research and monitoring was initiated in 1989 to investigate ecological interactions among fish in response to proposed supplementation of salmon and steelhead in the upper Yakima River basin. This is the seventh of a series of progress reports that address species interactions research and pre-supplementation monitoring of fishes in the Yakima River basin. Data have been collected prior to supplementation to characterize the ecology and demographics of non-target taxa (NTT) and target taxon, and develop methods to monitor interactions and supplementation success. Major topics of this report are associated with monitoring potential impacts to support adaptive management of NTT and baseline monitoring of fish predation indices on spring chinook salmon smolts. This report is organized into three chapters, with a general introduction preceding the first chapter. This annual report summarizes data collected primarily by the Washington Department of Fish and Wildlife (WDFW) between January 1, 1998 and December 31, 1998 in the Yakima basin, however these data were compared to data from previous years to identify preliminary trends and patterns.

  9. Yakima River Species Interactions Studies, Annual Report 2002.

    Energy Technology Data Exchange (ETDEWEB)

    Pearsons, Todd N.

    2003-05-01

    This report is intended to satisfy two concurrent needs: (1) provide a contract deliverable from the Washington Department of Fish and Wildlife (WDFW) to the Bonneville Power Administration (BPA), with emphasis on identification of salient results of value to ongoing Yakima/Klickitat Fisheries Project (YKFP) planning, and (2) summarize results of research that have broader scientific relevance. This is the eleventh of a series of progress reports that address species interactions research and supplementation monitoring of fishes in response to supplementation of salmon and steelhead in the upper Yakima River basin. This progress report summarizes data collected between January 1, 2002 and December 31, 2002. These data were compared to findings from previous years to identify general trends and make preliminary comparisons. Interactions between fish produced as part of the YKFP, termed target species or stocks, and other species or stocks (non-target taxa) may alter the population status of non-target species or stocks. This may occur through a variety of mechanisms, such as competition, predation, and interbreeding. Furthermore, the success of a supplementation program may be limited by strong ecological interactions such as predation or competition. Our work has adapted to new information needs as the YKFP has evolved. Initially, our work focused on interactions between anadromous steelhead and resident rainbow trout (for explanation see Pearsons et al. 1993), then interactions between spring chinook salmon and rainbow trout, and recently interactions between spring chinook salmon and highly valued nontarget taxa (NTT; e.g., bull trout); and interactions between strong interactor taxa (e.g., those that may strongly influence the abundance of spring chinook salmon; e.g., smallmouth bass) and spring chinook salmon. The change in emphasis to spring chinook salmon has largely been influenced by the shift in the target species planned for supplementation (Bonneville

  10. A Meta-study of musicians' non-verbal interaction

    DEFF Research Database (Denmark)

    Jensen, Karl Kristoffer; Marchetti, Emanuela

    2010-01-01

    Music can be seen as a social skilled practice, since the creation of good music is the result of a group effort. According to current literature, communication through non-verbal cues is an important factor in securing a good performance, since it allows musicians to correct each other without...... the music should be played and the intention to communicate through non-verbal interaction, which allows them to achieve their desire and improve the performance on-the-fly. The BDI model has proven useful in synthesising information and it is believed that this scientific-rational model will bring benefits...... interruptions. Hence, despite the fact that the skill to engage in a non-verbal interaction is described as tacit knowledge, it is fundamental for both musicians and teachers (Davidson and Good 2002). Typical observed non-verbal cues are for example: physical gestures, modulations of sound, steady eye contact...

  11. Study of the Interaction Model of PDC Cutters with Rock

    Directory of Open Access Journals (Sweden)

    Wang Jiajun

    2014-06-01

    Full Text Available The existing PDC cutters with rock interaction models does not match the actual drilling condition, because WOB can’t be loaded on their equipment, the influence of the cutting velocity on the force of cutters doesn’t be considered. A drilling experiment was carried out in the experimental device in which cutters can be loaded WOB. The relationship of cutting area, cutting speed, back dip angle of PDC cutter and rock performance with the force of PDC cutter were considered. The multiple nonlinear regression analysis were done on the basis of the experimental data, a new cutter-rock interaction model was established. The cutter area is the principal component influencing the force of cutters though the cluster analysis and principal component analysis. It is a logarithmic relationship between cutting velocity and the force of cutter, the theory of particle dynamics confirms this relationship.

  12. Studies of Peptide-Mineral Interactions and Biosilicification

    Science.gov (United States)

    2010-07-16

    of these complexing/ charge balancing agents simply by changing the silica source; Identification of polysilicic acids that interact with molecules...walls’ Phytochem , 70(17-18), 2089-2095 17. V. V. Annenkov, S. N. Zelinskiy, E. N. Danilovtseva, C C Perry (2009) Synthesis of biomimetic polyamines...that of the many peptides explored, each had a slightly different complexation behaviour with the fluorometric agent making it essential for all future

  13. EPR study of spermine interaction with multilamellar phosphatidylcholine liposomes.

    Science.gov (United States)

    Momo, F; Wisniewska, A; Stevanato, R

    1995-11-22

    The interaction of spermine with egg-yolk phosphatidylcholine liposomes was investigated. The EPR spin labeling technique evidenced that spermine induces modifications of some membrane functions of biological interest like water permeability and is a possible modulator of diffusion processes for charged and polar molecules. The association constant for a hypothesized complex between spermine and the phosphate group of phosphatidylcholine was evaluated by enzymatic methods.

  14. [Theoretical studies in weak, electromagnetic and strong interactions. Attachments

    Energy Technology Data Exchange (ETDEWEB)

    Nandi, S.

    1999-09-01

    The project covered a wide area of current research in theoretical high-energy physics. This included Standard Model (SM) as well as physics beyond the Standard Model. Specific topics included supersymmetry (SUSY), perturbative quantum chromodynamics (QCD), a new weak interaction for the third family (called topflavor), neutrino masses and mixings, topcolor model, Pade approximation, and its application to perturbative QCD and other physical processes.

  15. Team Interactions in Specialized Palliative Care Teams: A Qualitative Study

    OpenAIRE

    Klarare, Anna; Hagelin, Carina Lundh; Fürst, Carl Johan; Fossum, Bjoorn

    2013-01-01

    Background: Teamwork is a standard of care in palliative care and that is emphasized by leading organizations. When interdisciplinary teams communicate their varied assessments, outcomes may be more than additive due to the synthesis of information. Interprofessionality does not guarantee multidimensionality in health care interventions, however, and that interprofessional teams promote collaboration may be questioned. Aim: The aim was to explore team interaction among team members in special...

  16. Computational Studies about the Interactions of Nanomaterials with Proteins and their Impacts

    CERN Document Server

    An, Deyi; Li, Chunhua; Li, Jingyuan

    2015-01-01

    Intensive concerns about the biosafety of nanomaterials demand the systematic study of the mechanisms about their biological effects. Many biological effects can be attributed to the interaction of nanomaterials with protein and their impacts on protein function. On the other hand, nanomaterials exhibit the potential in a variety of biomedical applications, many of which also involve the direct interaction with protein. In this paper, we review some recent computational studies about this subject, especially the interaction of carbon and gold nanomaterials. Besides the hydrophobic and {\\pi}-stacking interactions, the interaction mode of carbon nanomaterials can be regulated by their functional groups. And the coating of gold nanomaterials also adjusts their interaction mode, in addition to the coordination interaction with cysteine's sulfur group and histidine's imidazole group. Moreover, nanomaterials can interact with multiple proteins and the impacts on protein activity are attributed to a wide spectrum of...

  17. Molecular Spectroscopic Study on the Interaction between Heparin and Neutral Red

    Institute of Scientific and Technical Information of China (English)

    Li ZHANG; Na LI; Feng Lin ZHAO; Ke An LI

    2004-01-01

    The interaction between heparin and neutral red was investigated by molecular spectroscopic methods. The change of all spectra suggested that positively charged neutral red had interacted with negatively charged heparin. The study of influence factors indicated that electrostatic force and hydrophobic bond might be involved in the interaction. The total binding number per disaccharide unit and intrinsic binding constant were obtained using Scatchard model.

  18. Transcription factors do it together : the hows and whys of studying protein-protein interactions

    NARCIS (Netherlands)

    Immink, R.G.H.; Angenent, G.C.

    2002-01-01

    Protein–protein interactions are intrinsic to virtually every cellular process. Recent breakthroughs in techniques to study protein-interaction and the availability of fully sequenced plant genomes have attracted many plant scientists to undertake the first steps in the field of protein interactions

  19. Study of the interfacial interactions in the molybdenite floatation system

    Institute of Scientific and Technical Information of China (English)

    WANG Hui; GU Guo-hua; FU Jian-gang; CHEN Li; HAO Ye

    2008-01-01

    Interfacial interactions involving Van der Waals force, hydrophobic attractive force and hydration exclusive force were investigated in this paper. The interfacial interactive free energy of a series of interfaces occurring between minerals, water, collectors and bubble was calculated. The results show that a Van der Waals attractive force and a hydrophobic attractive force exist between each mineral and water interface. The hydrophobic attractive force between molybdenite and water is markedly weaker than the hydrophobic attractive force between gangue and water. The hydrophobic attractive force between collector molecules and water is the main driving force that causes the collectors to become dispersed in the pulp. The strong hydrophobic attractive force between molybdenite and the bubble interface is the basic reason for the natural floatability of molybdenite. The Van der Waals force between molybdenite and the collectors is attractive in water solution, but it is not the cause of the main force between them. The main force that results in the collection effect is a hydrophobic attractive force caused by the Lewis acid-base interaction at the molybdenite surface. A floatation experiment shows that the adsorption intensity of the collector on the molybdenite surface is not the crucial factor for molybdenite floatation. Rather, the dispersing capability of the collector in the water phase and its selectivity for the various minerals in the floatation system are more important.

  20. Experimental study on interaction between simulated sandstone and acidic fluid

    Institute of Scientific and Technical Information of China (English)

    Zhang Yongwang; Zeng Jianhu; Yu Bingsong

    2009-01-01

    In order to investigate the controlling mechanism of temperature, fluid and other factors on water-rock interaction in the diagenetic process, we performed a series of simulated experiments on the interaction between two kinds of fluids with different salinity and a composite mineral system (simulated sandstone), which contains albite, K-feldspar and other minerals. The experimental results showed that acidity was the most important factor that affected the dissolution of minerals in the composite mineral system. The lower the pH value, the more easily the minerals dissolved. At the same pH value, the dissolution abilities of different acids for various mineral components were also different. Compared to hydrochloric acid (inorganic acid), oxalic acid (organic acid) was more able to dissolve aluminosilicate minerals. However, the dissolution ability of oxalic acid for carbonate minerals was lower than that of hydrochloric acid. In the process of fluid-rock interaction,dissolution of feldspar was relatively complicated. Increase of temperature would accelerate the dissolution of feldspar. Under acidic conditions, albite had a higher dissolution rate than K-feldspar. K-feldspar could dissolve and convert into montmorillonite and kaolinite, while albite could dissolve and convert into kaolinite both at 40℃ and 80℃. Presence of organic acid, and decrease of pH value and water salinity were all favorable for the dissolution of feldspar, but weakened the ability to form clay minerals.

  1. A Design Study of Direct-Touch Interaction for Exploratory 3D Scientific Visualization

    OpenAIRE

    Klein, Tijmen; Guéniat, Florimond; Pastur, Luc; Vernier, Frédéric; Isenberg, Tobias

    2012-01-01

    International audience; We present an interaction design study of several non-overlapping direct-touch interaction widgets, postures, and bi-manual techniques to support the needs of scientists who are exploring a dataset. The final interaction design supports navigation/zoom, cutting plane interaction, a drilling exploration, the placement of seed particles in 3D space, and the exploration of temporal data evolution. To ground our design, we conducted a requirements analysis and used a parti...

  2. Theoretical Study on the Intermolecular Interactions of Tetrazole Dimers

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Tetrazole monomers (Ⅰ,Ⅱ) and all of their possible stable dimers (1, 2, 3, 4, 5, 6, 7and 8) were fully optimized by DFT method at the B3LYP/6-311++G** level. Among the eight dimers, there were two 1H-tetrazole dimers, three 2H-tetrazole dimers and three hetero dimers of 1H-tetrazole and 2H-tetrazole. Vibrational frequencies were calculated to ascertain that each structure was stable (no imaginary frequencies). The basis set superposition errors (BSSE) are 2.78,2.28, 2.97, 2.75, 2.74, 2.18, 1.23 and 3.10 kJ/mol, and the zero point energy (ZPE) corrections for the interaction energies are 4.88, 4.18, 3.87, 3.65, 3.54, 3.22, 2.87 and 4.34 kJ/mol for 1, 2, 3, 4, 5, 6,7 and 8, respectively. After BSSE and ZPE corrections, the greatest corrected intermolecular interaction energy ofthe dimers is -43.71 kJ/mol. The charge redistribution mainly occurs on the very small. Natural bond orbital (NBO) analysis was performed to reveal the origin of the interaction. Based on the statistical thermodynamic method, the standard thermodynamic functions, heat capacities (C0p), entropies (S0T) and thermal corrections to enthalpy (H0T), and the changes of thermodynamic properties from monomer to dimer in the temperature range of 200.00 K to 700 K have been obtained. 1H-tetrazole monomer can spontaneously tum into two stable dimers at 298.15 K.

  3. Study on the optimum parameters for laser-solid interaction

    Institute of Scientific and Technical Information of China (English)

    Liyun Lin(林丽云); Shengbo Wang(王声波); Dahao Guo(郭大浩); Hongxing Wu(吴鸿兴); Xiaoping Xia(夏小平); Yusheng Dai(戴宇生)

    2003-01-01

    The optimum parameters for laser propulsion are discussed, such as laser induced pressure on targets,interaction parameters (Cm, Isp) and optimum laser intensity Is, etc. It is verified that the larger laserpower density will induce higher thrusting force. It is also found that, to drive a 1.010-kg target duringconfined laser ablation in vacuum and a 17.45-g one during direct laser ablation in air at the standardpressure, the needed minimum power intensities are on the same order of magnitude.

  4. Homogalacturonan deesterification during pollen–ovule interaction in Larix decidua Mill.: an immunocytochemical study

    OpenAIRE

    Rafińska, Katarzyna; Świdziński, Michał; Bednarska-Kozakiewicz, Elżbieta

    2014-01-01

    Studies on angiosperm plants have shown that homogalacturonan present in the extracellular matrix of pistils plays an important role in the interaction with the male gametophyte. However, in gymnosperms, knowledge on the participation of HG in the pollen–ovule interaction is limited, and only a few studies on male gametophytes have been reported. Thus, the aim of this study was to determine the distribution of HG in male gametophytes and ovules during their interaction in Larix decidua Mill. ...

  5. Common sources of bias in gene-lifestyle interaction studies of cardiometabolic disease

    DEFF Research Database (Denmark)

    Oskari Kilpeläinen, Tuomas

    2013-01-01

    The role of gene x lifestyle interactions in the development of cardiometabolic diseases is often highlighted, but very few robustly replicated examples of interactions exist in the literature. The slow pace of discoveries may largely be due to interaction effects being generally small in magnitude...... and/or more complex than initially thought. However, the progress may also be hindered by the poor accuracy in large-scale epidemiological studies to estimate the true interaction effect sizes. Often, this bias tends to underestimate the interaction effect, leading to inadequate statistical power...... to detect the interaction. In this review, I will discuss the most common sources of bias in the estimation of gene x lifestyle interactions, and will discuss how such factors could be addressed in the future to enhance our potential to identify and replicate interactions for cardiometabolic diseases....

  6. Progress at the WITCH experiment towards weak interaction studies

    CERN Document Server

    Tandecki, Michaël

    A measurement of the $\\beta$–ν angular correlation in nuclear $\\beta$- decay is a good probe to search for physics beyond the Standard Model, independent of assumptions like parity, charge and time reversal violation. The WITCH (Weak Interaction Trap for Charged Particles) experiment will measure this correlation with the aim of further constraining the possible existence of scalar currents in the weak interaction or find a positive indication. The setup is located at ISOLDE/CERN and consists of a double Penning trap system combined with a retardation spectrometer to probe the energy of the recoil ions from the $\\beta$- decay. The shape of the recoil ion energy spectrum allows to determine the $\\beta$–ν angular correlation coefficient, $a$. Past experiments have allowed to measure this parameter with a precision of 0.5–1 %. The aim of the WITCH experiment is to measure $a$ with a precision of about 0.5 %.\\\\ A first step towards this goal has already been taken in 2006 with the measurement of a recoil ...

  7. Transdisciplinarity in the study of undernutrition-infection interactions.

    Science.gov (United States)

    Ulijaszek, S

    1997-06-01

    Interactions between undernutrition, infection, and growth and development are complex, and are reviewed in this article, giving particular emphasis on the importance of diarrheal infection in this process. The effects of diet, nutrition and infection on the nutritional status of a child can vary according to the disease ecology, the age of the child, patterns of feeding and types of food consumed. There are two possible ways in which this relationship can begin; one in which poor nutritional status leads to impaired immunocompetence and reduced resistance to infection, and the other in which exposure to infectious disease can lead to appetite loss and anorexia, malabsorption, and elevated metabolism of energy and other nutrients. Once started, the interactions between these two major environmental stressors becomes increasingly complex, with the nature of the disease ecology influencing the balance of immunoparesis and adaptive immunity and its effect on subsequent disease experience. Furthermore, the disease ecology influences the type and extent of associated physiological phenomena including anorexia, fever, and malabsorption, all of which have an impact on nutritional status. Of disease categories, diarrhea has particularly potent effects in this relationship. The predicted impact of HIV infection among newborn infants is the earlier onset of the undernutrition-infection cycle, as low CD4+ T lymphocyte counts soon after birth are likely to predispose such infants to earlier opportunistic infection.

  8. Detection of gene x gene interactions in genome-wide association studies of human population data

    National Research Council Canada - National Science Library

    Musani, Solomon K; Shriner, Daniel; Liu, Nianjun; Feng, Rui; Coffey, Christopher S; Yi, Nengjun; Tiwari, Hemant K; Allison, David B

    2007-01-01

    Empirical evidence supporting the commonality of gene x gene interactions, coupled with frequent failure to replicate results from previous association studies, has prompted statisticians to develop...

  9. Alcohol-related breast cancer in postmenopausal women - effect of CYP19A1, PPARG and PPARGC1A polymorphisms on female sex-hormone levels and interaction with alcohol consumption and NSAID usage in a nested case-control study and a randomised controlled trial

    DEFF Research Database (Denmark)

    Kopp, Tine Iskov; Jensen, Ditte Marie; Ravn-Haren, Gitte

    2016-01-01

    Alcohol consumption is associated with increased risk of breast cancer (BC), and the underlying mechanism is thought to be sex-hormone driven. In vitro and observational studies suggest a mechanism involving peroxisome proliferator-activated receptor gamma (PPARγ) in a complex with peroxisome...... proliferator-activated receptor gamma coactivator 1-α (PGC-1α) and interaction with aromatase (encoded by CYP19A1). Use of non-steroidal anti-inflammatory drugs (NSAID) may also affect circulating sex-hormone levels by modifying PPARγ activity. In the present study we assessed whether genetic variation in CYP......19A1 is associated with risk of BC in a case-control study group nested within the Danish "Diet, Cancer and Health" cohort (ncases = 687 and ncontrols = 687) and searched for gene-gene interaction between CYP19A1 and PPARGC1A, and CYP19A1 and PPARG, and gene-alcohol and gene-NSAID interactions...

  10. Study on the fine control of atoms by coherent interaction

    Energy Technology Data Exchange (ETDEWEB)

    Min, Han Jae; Rho, S. P.; Park, H. M.; Lee, K. S.; Rhee, Y. J.; Yi, J. H.; Jeong, D. Y.; Jung, E. C.; Choe, A. S.; Lee, J. M

    1999-01-01

    The doppler-free saturation spectroscopy of Na atoms has been performed and the proper conditions for the frequency stabilization of narrow band cw dye lasers, which was used as laser sources for the laser cooling and trapping, have been obtained as follows : a) optimum pressure of a Na vapor cell: 10 mTorr b) intensity of a pump laser : a few {mu}W c) intensity of a probe laser : 1/10 of that of a pump laser. EIT (Electromagnetically Induced Transparency) generated by coherent laser-atom interactions was investigated experimentally and analyzed theoretically. The absorption of a probe laser could be remarkably reduced more than 90 % due to EIT effect. The EIT spectrum as narrow as 6 MHz which is even narrower than the natural linewidth of an excited state could be obtained under proper conditions.

  11. Copper-ceria interaction: A combined photoemission and DFT study

    Science.gov (United States)

    Szabová, Lucie; Skála, Tomáš; Matolínová, Iva; Fabris, Stefano; Farnesi Camellone, Matteo; Matolín, Vladimír

    2013-02-01

    Stoichiometric and partially reduced ceria films were deposited on preoxidized Ru(0 0 0 1) crystal by Ce evaporation in oxygen atmosphere of different pressures at 700 K. Copper-ceria interaction was investigated by deposition of metalic copper on both types of substrate. The samples were characterized by low energy electron diffraction (LEED), X-ray photoelectron spectroscopy (XPS) of core states and resonant photoelectron spectroscopy (RPES) of the valence bands. Copper adsorption on stoichiometric ceria caused reduction of CeO2, while on the oxygen-defficient ceria it partially reoxidized the substrate. This is in agreement with DFT+U calculations of copper adsorption on stoichiometric and defective ceria surfaces.

  12. A structural study of porphyrins interacting with a metallic surface

    Energy Technology Data Exchange (ETDEWEB)

    Brede, Jens; Hoffmann, Germar; Wiesendanger, Roland [Institut of Applied Physics, University of Hamburg (Germany)

    2008-07-01

    A porphyrin is a heterocyclic macrocycle derived from pyrrolic subunits interconnected via methine bridges. Porphyrins are an ubiquitous class of naturally occurring compounds with important biological representatives including hemes and chlorophylls. We prepared various tetra phenyl prophyrins (TPP) with different central metal (M) ions on metallic substrates. The molecular systems were investigated by scanning tunnelling microscopy and spectroscopy. The experiments were performed in a home-built low temperature STM working at 6 K in ultra-high vacuum conditions. Upon deposition of porphyrins on metal substrates the aromatic core of the molecule may undergo a structural deformation depending on the details of the molecule-substrate interaction. We will discuss the structural conformation of TPPs and their electronic properties.

  13. Fluorescence Spectra Studies on the Interaction between Lanthanides and Calmodulin

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The conformation of Calmodulin(CaM) induced by lanthanides has been examined using fluorescence methods.With the addition of lanthanide (Ln3+), the intrinsic fluorescence intensity of CaM without calcium ions (Apo-CaM) first increases and then decreases.Ln3+ causes the decrease of intrinsic fluorescence intensity of calcium saturated CaM (Ca2+4-CaM) only at high concentrations.At low concentrations, Ln3+ results not only in the enhancement of fluorescence intensity of Apo-CaM, but also in a blue shift of the maximum emission wavelengh of dansyl labeled calmodulin(Apo-D-CaM).The molecular mechanism of the interaction between Ln3+ and CaM has been discussed in the light of the fluorescence spectra.

  14. Polyelectrolyte Conformation, Interactions and Hydrodynamics as Studied by Light Scattering.

    Science.gov (United States)

    Ghosh, Snehasish

    Polyelectrolyte conformation, interactions and hydrodynamics show a marked dependence on the ionic strength (C_{rm s}) of the medium, the concentration (C_{rm p}) of the polymer itself and their charge density (xi). The apparent electrostatic persistence length obtained from static light scattering varied approximately as the inverse square root of C _{rm s} for highly pure, high molecular weight hyaluronate (HA) as well as for variably ionized acrylamide/sodium acrylate copolymers (NaPAA), and linearly with xi. The experimental values of persistence length and second virial coefficient (A_2) are compared to predictions from theories based on the Debye-Huckel approximation for the Poisson-Boltzmann equation and on excluded-volume. Although the mean square radius of gyration () depended strongly on C _{rm s}. decreasing with increasing C_{rm s} for both HA and NaPAA indicating clear evidence of polyion expansion, dynamic light scattering values of the translational diffusion coefficient (D) remains constant when extrapolated to infinite polymer concentration for both the polymers. The behavior of D is compared to predictions from coupled mode theory in the linear limit. The effects of NaOH on the conformations, interactions, diffusion and hydrolysis rates of HA are characterized in detail using static, dynamic and time-dependent light scattering supplemented by size exclusion chromatography (SEC). For the HA , A_2 and the hydrolysis rates all resemble superposing titration curves, while the D remains independent of both the concentration of NaOH, and the contraction of . The indication is that the interactions, conformations and the hydrolysis rates are all controlled by the titration of the HA hydroxyl groups by the NaOH to yield -O ^-, which (i) destroys single strand hydrogen bonds, leading to de-stiffening and contraction of the HA coil and a large decrease in intermolecular interaction, and (ii) slowly depolymerizes HA. The experimental results of HA

  15. Theorizing Language and Discourse for the Interactional Study of Identities.

    Science.gov (United States)

    Korobov, Neill

    2017-03-01

    The following commentary critically reflects on the pragmatic and semiotic approach to language and identity articulated by Tapia, Rojas, and Picado (Culture & Psychology, Tapia et al. 2017). The following questions are central: 1) What theoretical position is (tacitly) being articulated regarding the nature of language and discourse? Although the authors admit that an explicit theorization of language and discourse is not their focus, the absence of a clear theoretical position is conspicuously problematic. And 2) is there an unintended cognitivism present in the way the authors formulate the relationship between language/discourse and identity? After discussing these questions, select parts of a radical interactional approach, grounded in discursive positioning, will be presented as an amendment to the present work, insofar as it attempts to both articulate a progressive theorization of language and discourse and avoid an unintended slide into cognitivism.

  16. Experimental study on interaction and coalescence of synchronized multiple bubbles

    Science.gov (United States)

    Cui, P.; Wang, Q. X.; Wang, S. P.; Zhang, A. M.

    2016-01-01

    Experiments are carried out on the interaction and coalescence of two, three, and four bubbles with approximately the same sizes, distributed evenly and symmetrically. The bubbles are generated simultaneously by electric discharges, using an in-house designed series circuit, and their interaction is captured using a high-speed camera. Particular attentions are paid to if/when coalescence of bubbles happens and the motion of the joined bubbles. Some new features are observed, which depend mainly on the dimensionless distance γbb = dbb/Rmax, where dbb is the inter-bubble distance and Rmax is the maximum bubble radius. For γbb > 2, a jet forms and penetrates each side bubble, directed to the center of the configuration, resulting in a protrusion. Towards the end of collapse, a large portion of bubble gases is compressed into the protrusion from the main part of the toroidal bubble. For γbb bubbles coalesce during expansion, and the part of the joined bubble's surface distal from the center of the configuration collapses faster than elsewhere. The experiments show that the oscillation period of multi-bubbles does not change appreciably without coalescence but increases significantly with coalescence. For three bubbles initiated at collinear positions with γbb > 2, the jets that form from the side bubbles are towards the middle, and the middle bubble splits into two parts, moving towards the two side bubbles. For γbb bubbles merge with the middle bubble during expansion, forming an ellipsoid bubble; the joined bubble collapses predominantly from two sides, where two inward jets form towards the end of collapse.

  17. A comprehensive study method for lifeline system interaction under seismic conditions

    Institute of Scientific and Technical Information of China (English)

    姚保华; 谢礼立; 火恩杰

    2004-01-01

    The mechanism of lifeline system interaction is analyzed and the method and its corresponding result for categorizing the lifeline system in terms of interaction are presented. Various methods for the different kind of interaction are reviewed in this paper. For the function interaction of the lifeline system, an all-round study method is recommended. A WebGIS based aided decision-making method for the post-earthquake restoration of multi-lifeline system is also presented. Meanwhile, some key-points for lifeline system interaction are discussed.

  18. Hydrodynamic interaction between two vesicles in a linear shear flow: asymptotic study.

    Science.gov (United States)

    Gires, P Y; Danker, G; Misbah, C

    2012-07-01

    Interactions between two vesicles in an imposed linear shear flow are studied theoretically, in the limit of almost spherical vesicles, with a large intervesicle distance, in a strong flow, with a large inner to outer viscosity ratio. This allows to derive a system of ordinary equations describing the dynamics of the two vesicles. We provide an analytic expression for the interaction law. We find that when the vesicles are in the same shear plane, the hydrodynamic interaction leads to a repulsion. When they are not, the interaction may turn into attraction instead. The interaction law is discussed and analyzed as a function of relevant parameters.

  19. Drug interaction studies on new drug applications: current situations and regulatory views in Japan.

    Science.gov (United States)

    Nagai, Naomi

    2010-01-01

    Drug interaction studies on new drug applications (NDAs) for new molecular entities (NMEs) approved in Japan between 1997 and 2008 are examined in the Pharmaceuticals and Medical Devices Agency (PMDA). The situations of drug interaction studies in NDAs have changed over the past 12 years, especially in metabolizing enzyme and transporter-based drug interactions. Materials and approaches to study drug-metabolizing enzyme-based drug interactions have improved, and become more rational based on mechanistic theory and new technologies. On the basis of incremental evidence of transporter roles in human pharmacokinetics, transporter-based drug interactions have been increasingly studied during drug development and submitted in recent NDAs. Some recently approved NMEs include transporter-based drug interaction information in their package inserts (PIs). The regulatory document "Methods of Drug Interaction Studies," in addition to recent advances in science and technology, has also contributed to plan and evaluation of drug interaction studies in recent new drug development. This review summarizes current situations and further discussion points on drug interaction studies in NDAs in Japan.

  20. Hyperfine Interactions in Iron Meteorites: Comparative Study by Moessbauer Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Oshtrakh, M. I., E-mail: oshtrakh@mail.utnet.ru [Ural State Technical University - UPI, Faculty of Physical Techniques and Devices for Quality Control (Russian Federation); Milder, O. B. [Ural State Technical University - UPI, Faculty of Experimental Physics (Russian Federation); Grokhovsky, V. I. [Ural State Technical University - UPI, Faculty of Physical Techniques and Devices for Quality Control (Russian Federation); Semionkin, V. A. [Ural State Technical University - UPI, Faculty of Experimental Physics (Russian Federation)

    2004-11-15

    The iron meteorites Sikhote-Alin, Bilibino, Chinga and Dronino with different Ni concentration and terrestrial age were studied by Moessbauer spectroscopy. Different Moessbauer hyperfine parameters were determined for studied meteorites and possible Fe-Ni phases were supposed.

  1. Interaction study of paracetamol with saturated (capric) and unsaturated (oleic) fatty acids.

    Science.gov (United States)

    Misra, Arun Kumar; Misra, Manju; Panpalia, Gopal Madanlal; Dorle, Avinash Keshav

    2007-01-01

    Interaction study of paracetamol with saturated and unsaturated fatty acids, namely, capric and oleic acid have been performed by using serial dilution method, release behavior, FT-IR, and DSC study. Preliminary investigations by release studies indicated the possibility of interaction between paracetamol and fatty acids. UV-studies failed to detect any interaction between paracetamol and fatty acids. The possibility of hydrogen bonding between amino group of paracetamol and carbonyl group of fatty acids was revealed by FT-IR study. Polymorphic transition of paracetamol in the binary sample of paracetamol-capric acid was identified by DSC studies. However, no such possibility was detected in paracetamol-oleic acid mixture.

  2. Preliminary study: Moisture-polymer interaction. Stuby objectives

    Science.gov (United States)

    Wen, L. C.

    1985-06-01

    The problems associated with mathematically modeling water-module interaction phenomena, including sorption and desorption, diffusion, and permeation are discussed. With reliable analytical models, an extensive materials data base, and solar radiation surface meteorological observations (SOLMET) weather data, predicting module lifetimes in realistic environments can become a practical reality. The status of the present techniques of simulating the various transport mechanisms was reported. The Dent model (a modified Brunauer-Emmet-Teller) approach represented polyvinyl butyral (PVB) sorption data. A 100-layer material model and Fick's diffusion model gave diffusivity values exhibiting adequate agreement with those measured for PVB. Diffusivity of PVB is concentration dependent, decreasing as the water content in PVB increases. The temperature dependence of diffusion in PVB is well modeled by the Arrhenius rate equation. Equilibrium conductivity and leakage current data are well represented by Hearle's model for bulk ionic conductivity. A nodal network analysis using the Systems Improved Numerical Differencing Analyzer (SINDA) Thermal Analyzer gave reasonable correlation with measurable data. It is concluded that realistic lifetime predictions seem to be feasible.

  3. A comprehensive study to protein retention in hydrophobic interaction chromatography.

    Science.gov (United States)

    Baca, Martyna; De Vos, Jelle; Bruylants, Gilles; Bartik, Kristin; Liu, Xiaodong; Cook, Ken; Eeltink, Sebastiaan

    2016-10-01

    The effect of different kosmotropic/chaotropic salt systems on retention characteristics of intact proteins has been examined in hydrophobic interaction chromatography (HIC). The performance was assessed using different column chemistries, i.e., polyalkylamide, alkylamine incorporating hydrophobic moieties, and a butyl chemistry. Selectivity in HIC is mainly governed by the salt concentration and by the molal surface tension increment of the salt. Typically, a linear relationship between the natural logarithm of the retention factor and the salt concentration is obtained. Using a 250mm long column packed with 5μm polyalkylamide functionalized silica particles and applying a 30min linear salt gradient, a peak capacity of 78 was achieved, allowing the baseline separation of seven intact proteins. The hydrophobicity index appeared to be a good indicator to predict the elution order of intact proteins in HIC mode. Furthermore, the effect of adding additives in the mobile phase, such as calcium chloride (stabilizing the 3D conformation of α-lactalbumin) and isopropanol, on retention properties has been assessed. Results indicate that HIC retention is also governed by conformational in the proteins which affect the number of accessible hydrophobic moieties.

  4. A Study on Dynamic Response of Cable-Seabed Interaction

    Institute of Scientific and Technical Information of China (English)

    WANG Fei; HUANG Guo-liang; DENG De-heng; TU Xing-hua

    2009-01-01

    A numerical method is developed to investigate the dynamic response of cable-seabed interaction in this paper. The motion of cable is described by the Lumped Parameter Method, while the seabed, unlike the prevailing simplified model of elastic foundation, is modeled as an irregular continuous rigid surface with rebound and friction existing, and the forces exerted by the seabed consist of normal counterforce and isotropic tangential Coulomb friction resistance. To describe the detailed dynamic response, two coefficients are introduced by analogy with the theory of rigid body collision with friction. The cable-seabed kinematic and dynamic contact conditions are formulated subsequently, and are used to incorporate the seabed effect into the cable dynamics to produce a set of ordinary differential governing equations. In this paper, we employ 4th order Runge-Kutta method to solve these equations. Several simulation cases are presented to illustrate the seabed effect. The results show that friction and impact have a prominent influence on the statics and dynamics of the cable.

  5. Micromechanical study of protein-DNA interactions and chromosomes

    Science.gov (United States)

    Marko, John

    I will discuss micromechanics experiments that our group has used to analyze protein-DNA interactions and chromosome organization. In single-DNA experiments we have found that a feature of protein-DNA complexes is that their dissociation rates can depend strikingly on bulk solution concentrations of other proteins and DNA segments; I will describe experiments which demonstrate this effect, which can involve tens-fold changes in off-rates with submicromolar changes in solution concentrations. Second, I will discuss experiments aimed at analyzing large-scale human chromosome structure; we isolate metaphase chromosomes, which in their native form behave as remarkably elastic networks of chromatin. Exposure to DNA-cutting restriction enzymes completely eliminates this elasticity, indicating that there is not a mechanically contiguous protein ''scaffold'' from which the chromosome gains its stability. I will show results of siRNA experiments indicating that depletion of condensin proteins leads to destabilization of chromosome mechanics, indicating condensin's role as the major chromatin ''cross-linker'' in metaphase chromosomes. Finally I will discuss similar experiments on human G1 nuclei, where we use genetic and chemical modifications to separate the contributions of the nuclear lamina and chromatin to the mechanical stiffness of the nucleus as a whole. Supported by the NSF (DMR-1206868, MCB-1022117) and the NIH (GM105847, CA193419).

  6. A study of polymer-surfactant interactions by neutron reflectivity

    CERN Document Server

    Warren, N

    1999-01-01

    surfactants and their relative levels of interaction with the polymer. The surface behaviour of these systems was observed to be in many ways more remarkable than that of the bulk solution. In the high total surfactant concentration range, once all polymer molecules were associated with bound micelles, the extent of adsorption at the air-liquid interface was found to be dominated largely, as might be expected, by the solution monomer concentrations of the two surfactants. Prior to this, however, adsorption was dominated by the presence of a very surface active polymer-SDS complex which gave rise to enhanced SDS adsorption and low surface tensions compared with those found in polymer-free systems. The origin of this effect, being the stabilisation of the adsorbed SDS monolayer due to a reduction in the inter-headgroup repulsions through screening, by the charged polymer segments, suggests that this may be a characteristic feature of systems continuing a polyelectrolyte and an oppositely charged surfactant. In ...

  7. Comprehensive study of tartrazine/cationic surfactant interaction.

    Science.gov (United States)

    Shahir, Afshin Asadzadeh; Javadian, Soheila; Razavizadeh, Bi Bi Marzieh; Gharibi, Hussein

    2011-12-15

    Interaction of a food dye, tartrazine, with some cationic conventional and gemini surfactants, tetradecyltrimethylammonium bromide (TTAB), N,N'-ditetradecyl-N,N,N',N'-tetramethyl-N,N'-butanediyl-diammonium dibromide (14,4,14), and N,N'-didodecyl-N,N,N',N'-tetramethyl-N,N'-butanediyl-diammonium dibromide (12,4,12), were first investigated comprehensively employing conductometry, tensiometry, and UV-visible spectroscopy. Tartrazine was found to behave in the same manner as aromatic counterions. The formation of ion pairs reflected as a considerable increase of the surfactant efficiency in tensiometry plots and their stoichiometry were determined by Job's method of continuous variations. For the tartrazine/TTAB system, nonionic DS(3), ionic DS(2-), and/or DS(2)(-) ion pairs, their small premicelles, and tartrazine-rich micelles were constituted as well as dye-containing TTAB-rich micelles. Insoluble J-aggregates of DS(-) ion pairs and cylindrical surfactant-rich micelles were also formed in tartrazine/gemini surfactant systems and recognized by transmission electron microscopy. The zeta potential and the size of the aggregates were determined using dynamic light scattering and confirmed the suggested models for the processes happening in each system. Cyclic voltammetry was applied successfully to track all of these species using tartrazine's own reduction peak current for the first time.

  8. Mathematics for physicists and engineers fundamentals and interactive study guide

    CERN Document Server

    Weltner, Klaus; Weber, Wolfgang J; Schuster, Peter; Grosjean, Jean

    2014-01-01

    This textbook offers an accessible and highly approved approach which is characterized by the combination of the textbook with a detailed study guide available online at our repository extras.springer.com. This study guide divides the whole learning task into small units which the student is very likely to master successfully. Thus he or she is asked to read and study a limited section of the textbook and to return to the study guide afterwards. Working with the study guide his or her learning results are controlled, monitored and deepened by graded questions, exercises, repetitions and finally by problems and applications of the content studied. Since the degree of difficulties is slowly rising the students gain confidence and experience their own progress in mathematical competence thus fostering motivation. Furthermore in case of learning difficulties he or she is given supplementary explanations and in case of individual needs supplementary exercises and applications. So the sequence of the studies is ind...

  9. Progress in the studies of electrochemically controllable host-guest interactions

    Institute of Scientific and Technical Information of China (English)

    LIU Jing; LI Yuangang; FANG Yu

    2005-01-01

    Studies on the electrochemically controllable host-guest interactions have received considerable attention since the middle of the 1980s. In this paper, progress in such studies is reviewed according to the types of the hosts, including cyclodextrin, calixarene,cucurbituril, cyclophane, and so on. In addition, perspectives for the future development and potential applications of the interactions are discussed.

  10. Fundamental studies of hydrogen interaction with supported meta and bimetallic catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Bhatia, S.

    1993-12-07

    The thesis is divided into 3 parts: interaction of H with silica supported Ru catalysts (high pressure in situ NMR), in situ NMR study of H interaction with supported Ru-group IB bimetallic catalysts, and in-situ NMR study of H effects on silica-supported Pt, Rh and Ru catalysts.

  11. Teacher-Student Interactions: Four Case Studies of Gender in Physical Education

    Science.gov (United States)

    Davis, Kathryn; Nicaise, Virginia

    2011-01-01

    The aim of this study was to better understand gender interactions between teachers and students in high school physical education. Gender interactions were explored in relation to the theory of reflective practice. Interview data were examined as four case studies using individual and cross-case inductive analysis. Two common themes emerged: (a)…

  12. Model plants for studying the interaction between Methylobacterium mesophilicum and Xylella fastidiosa

    NARCIS (Netherlands)

    Andreote, FD; Lacava, PT; Gai, CS; Araujo, WL; Maccheroni, W; van Overbeek, LS; van Elsas, JD; Azevedo, JL

    2006-01-01

    Over the last few years, endophytic bacterial communities associated with citrus have been studied as key components interacting with Xylella fastidiosa. In this study, we investigated the possible interaction between the citrus endophyte Methylobacterium mesophilicum SR1.6/6 and X. fastidiosa in mo

  13. Model Plants for Studying the Interaction between Methylobacterium mesophilicum and Xylella fastidiosa

    NARCIS (Netherlands)

    Andreote, F.D.; Lacava, P.T.; Araújo, W.L.; Maccheroni Jr., W.; Overbeek, van L.S.; Elsas, van J.D.; Azevedo, J.L.

    2006-01-01

    Over the last few years, endophytic bacterial communities associated with citrus have been studied as key components interacting with Xylella fastidiosa. In this study, we investigated the possible interaction between the citrus endophyte Methylobacterium mesophilicum SR1.6/6 and X. fastidiosa in mo

  14. A Laboratory-Intensive Course on the Experimental Study of Protein-Protein Interactions

    Science.gov (United States)

    Witherow, D. Scott; Carson, Sue

    2011-01-01

    The study of protein-protein interactions is important to scientists in a wide range of disciplines. We present here the assessment of a lab-intensive course that teaches students techniques used to identify and further study protein-protein interactions. One of the unique elements of the course is that students perform a yeast two-hybrid screen…

  15. [Application and development of spectroscopy methodologies in the study on non-covalent interactions].

    Science.gov (United States)

    Li, Rui; Dai, Ben-Cai; Zhao, Yong-De; Lu, Kui

    2009-01-01

    Spectrophotometric method is widely used in the structure determination of biologic macromolecules and non-covalent interactions study for its convenience and speed. In the present paper, spectroscopy methodologies in the study of non-covalent interactions between small-molecule and biomacromolecule is comprehensively reviewed with 25 references. This review article focuses on the applications and development of common spectroscopy methodologies in the study of non-covalent interactions between small molecule and biomacromolecule,including the UV, fluorescence, CD, IR, Raman, resonance light scattering technique and SPR. The advantages and disadvantages of spectroscopy methodologies are also described. UV-Vis absorption spectrum (UV) method is widely used in the study of non-covalent interactions for its convenience and speed. The binding site number, the apparent binding constant and the interaction mode of non-covalent interactions can be obtained by fluorescence spectrum method. Circular dichroism (CD) method is effective way in the study of non-covalent interactions measure. Spectroscopy information about protein secondary structure and conformation can be acquired by infrared spectrometry (IR) method. Raman spectroscopy method is a better way to investigate the conformation change in macromolecules in solution. Non-covalent interactions can be measured by surface plasma resonance (SPR) method under the natural active condition. X-ray diffraction analysis method is better for non-covalent interactions research, but it is difficult to cultivate crystalline complex.

  16. Studying protein-protein interactions via blot overlay/far western blot.

    Science.gov (United States)

    Hall, Randy A

    2015-01-01

    Blot overlay is a useful method for studying protein-protein interactions. This technique involves fractionating proteins on SDS-PAGE, blotting to nitrocellulose or PVDF membrane, and then incubating with a probe of interest. The probe is typically a protein that is radiolabeled, biotinylated, or simply visualized with a specific antibody. When the probe is visualized via antibody detection, this technique is often referred to as "Far Western blot." Many different kinds of protein-protein interactions can be studied via blot overlay, and the method is applicable to screens for unknown protein-protein interactions as well as to the detailed characterization of known interactions.

  17. Interactive Volcano Studies and Education Using Virtual Globes

    Science.gov (United States)

    Dehn, J.; Bailey, J. E.; Webley, P.

    2006-12-01

    Internet-based virtual globe programs such as Google Earth provide a spatial context for visualization of monitoring and geophysical data sets. At the Alaska Volcano Observatory, Google Earth is being used to integrate satellite imagery, modeling of volcanic eruption clouds and seismic data sets to build new monitoring and reporting tools. However, one of the most useful information sources for environmental monitoring is under utilized. Local populations, who have lived near volcanoes for decades are perhaps one of the best gauges for changes in activity. Much of the history of the volcanoes is only recorded through local legend. By utilizing the high level of internet connectivity in Alaska, and the interest of secondary education in environmental science and monitoring, it is proposed to build a network of observation nodes around local schools in Alaska and along the Aleutian Chain. A series of interactive web pages with observations on a volcano's condition, be it glow at night, puffs of ash, discolored snow, earthquakes, sounds, and even current weather conditions can be recorded, and the users will be able to see their reports in near real time. The database will create a KMZ file on the fly for upload into the virtual globe software. Past observations and legends could be entered to help put a volcano's long-term activity in perspective. Beyond the benefit to researchers and emergency managers, students and teachers in the rural areas will be involved in volcano monitoring, and gain an understanding of the processes and hazard mitigation efforts in their community. K-12 students will be exposed to the science, and encouraged to participate in projects at the university. Infrastructure at the university can be used by local teachers to augment their science programs, hopefully encouraging students to continue their education at the university level.

  18. Mathematics for physicists and engineers fundamentals and interactive study guide

    CERN Document Server

    Weltner, Klaus; Grosjean, Jean; Schuster, Peter

    2009-01-01

    Mathematics is the basic language in physics and engineering. It is an essential tool which first and second year students have to master as soon as possible. A lack of competence in mathematics is the main reason for failure and drop out in the beginning periods of study. This textbook offers an accessible and highly approved approach which is characterized by the combination of the textbook with a detailed study guide available online at extras.springer.com. This study guide divides the whole learning task into small units which the student is very likely to master successfully. Thus he or she is asked to read and study a limited section of the textbook and to return to the study guide afterwards. Working with the study guide his or her learning results are controlled, monitored and deepened by graded questions, exercises, repetitions and finally by problems and applications of the content studied. Since the degree of difficulties is slowly rising the students gain confidence and experience their own progre...

  19. Surface modification for interaction study with bacteria and preosteoblast cells

    Science.gov (United States)

    Song, Qing

    Surface modification plays a pivotal role in bioengineering. Polymer coatings can provide biocompatibility and biofunctionalities to biomaterials through surface modification. In this dissertation, initiated chemical vapor deposition (iCVD) was utilized to coat two-dimensional (2D) and three-dimensional (3D) substrates with differently charged polyelectrolytes in order to generate antimicrobial and osteocompatible biomaterials. ICVD is a modified CVD technique that enables surface modification in an all-dry condition without substrate damage and solvent contamination. The free-radical polymerization allows the vinyl polymers to conformally coat on various micro- and nano-structured substrates and maintains the delicate structure of the functional groups. The vapor deposition of polycations provided antimicrobial activity to planar and porous substrates through destroying the negatively charged bacterial membrane and brought about high contact-killing efficiency (99.99%) against Gram-positive Bacillus subtilis and Gram-negative Escherichia coli. Additionally, the polyampholytes synthesized by iCVD exhibited excellent antifouling performance against the adhesion of Gram-positive Listeria innocua and Gram-negative E. coli in phosphate buffered saline (PBS). Their antifouling activities were attributed to the electrostatic interaction and hydration layers that served as physical and energetic barriers to prevent bacterial adhesion. The contact-killing and antifouling polymers synthesized by iCVD can be applied to surface modification of food processing equipment and medical devices with the aim of reducing foodborne diseases and medical infections. Moreover, the charged polyelectrolyte modified 2D polystyrene surfaces displayed good osteocompatibility and enhanced osteogenesis of preosteoblast cells than the un-modified polystyrene surface. In order to promote osteoinduction of hydroxyapatite (HA) scaffolds, bioinspired polymer-controlled mineralization was conducted

  20. Interactions between ciprofloxacin and antacids--dissolution and adsorption studies.

    Science.gov (United States)

    Arayne, M Saeed; Sultana, Najma; Hussain, Fida

    2005-01-01

    Ciprofloxacin is a fluorinated quinolone antibacterial agent extensively used against both Gram-positive and Gram-negative microorganisms. In certain polytherapy programs, ciprofloxacin can be administered with some antacids that could modify its dissolution rate and reduce its absorption leading to therapeutic failure. The aim of this study was to evaluate the influence of some antacids on the availability of ciprofloxacin. The release of ciprofloxacin from tablets in the presence of antacids, such as sodium bicarbonate, calcium hydroxide, calcium carbonate, aluminum hydroxide, magnesium hydroxide, magnesium carbonate, magnesium trisilicate and magaldrate was studied on BP 2002 dissolution test apparatus. These studies were carried out in simulated gastric and intestinal juices for 3 hours at 37 degrees C. The results confirmed that the dissolution rate of tablets was markedly retarded in the presence of all the antacids studied. Magaldrate and calcium carbonate in simulated gastric juice exhibited relatively higher adsorption capacities, as did magnesium trisilicate and calcium hydroxide in simulated intestinal juice.

  1. A Study on Immersion of Hand Interaction for Mobile Platform Virtual Reality Contents

    OpenAIRE

    Seunghun Han; Jinmo Kim

    2017-01-01

    This study proposes gaze-based hand interaction, which is helpful for improving the user’s immersion in the production process of virtual reality content for the mobile platform, and analyzes efficiency through an experiment using a questionnaire. First, three-dimensional interactive content is produced for use in the proposed interaction experiment while presenting an experiential environment that gives users a high sense of immersion in the mobile virtual reality environment. This is design...

  2. Atomic force microscopy study of cellulose surface interaction controlled by cellulose binding domains

    OpenAIRE

    Nigmatullin, R.; Lovitt, R.; Wright, C; Linder, M.; Nakari-Setälä, T; Gama, F. M.

    2004-01-01

    Colloidal probe microscopy has been used to study the interaction between model cellulose surfaces and the role of cellulose binding domain (CBD), peptides specifically binding to cellulose, in interfacial interaction of cellulose surfaces modified with CBDs. The interaction between pure cellulose surfaces in aqueous electrolyte solution is dominated by double layer repulsive forces with the range and magnitude of the net force dependent on electrolyte concentration. AFM imaging reve...

  3. Genetic control of eosinophilia in mice: gene(s) expressed in bone marrow-derived cells control high responsiveness

    Energy Technology Data Exchange (ETDEWEB)

    Vadas, M.A.

    1982-02-01

    A heterogeneity in the capacity of strains of mice to mount eosinophilia is described. BALB/c and C3H are eosinophil high responder strains (EO-HR) and CBA and A/J are eosinophil low responder strains (EO-LR), judged by the response of blood eosinophils to Ascaris suum, and the response of blood, bone marrow, and spleen eosinophils to keyhole limpet hemocyanin given 2 days after 150 mg/kg cyclophosphamide. Some of the gene(s) for high responsiveness appear to be dominant because (EO-HR x EO-LR)F/sub 1/ mice were intermediate to high responders. This gene is expressed in bone marrow-derived cells because radiation chimeras of the type EO-HR..-->..F/sub 1/ were high responders and EO-LR..-->..F/sub 1/ were low responders. This description of a genetic control of eosinophilia in mice may be useful in understanding the role of this cell in parasite immunity and allergy.

  4. Toward the gene(s) for Wiedemann-Beckwith syndrome and associated tumors in two different regions of 11p15

    Energy Technology Data Exchange (ETDEWEB)

    Henry, J.; Chehenase, V.; Boulevin, C. [INSERM, Paris (France)] [and others

    1994-09-01

    Wiedemann-Beckwith syndrome (WBS) is a malformation syndrome associated with predisposition to different types of tumors (WT, ADCC). Cytogenetic and familial studies mapped the WBS locus to 11p15.5. Genomic imprinting has been implicated in the expression of the syndrome. Using 11p15 specific markers we have determined the parental origin of both chromosomes 11 in sporadic WBS cases. Probands in 5 out of 26 informative families (25%) displayed uniparental disomy (UPD) corresponding to a paternal isodisomy for region 11p15.5. Mosaic phenotypes reflect the timing of their origin and the fate of cells involved as well as the cell-specific pattern of imprinting. Somatic mosaicism for UPD may thus explain the incomplete forms of WBS, the association of hemihypertrophy in sporadic WBS and even some cases of isolated hemihypertrophy. Moreover, the risk (60%) of developing a tumor seems higher for patients with paternal 11p UPD than for WBS patients in general (7.5%). Two different genomic libraries specific for region 11p15.5 were constructed and screened to isolate and characterize the gene(s) responsible for WBS and/or tumor progression. The characterization and and the localization of these cDNAs are in progress. 5 CA repeats genetically mapped in 11p15 were used to isolate YACs (CEPH). These CA repeats are now physically mapped using a panel of hybrids specific for the 11p15 region, and the contigs of YACs mapping in the regions of interest will be used to isolate coding sequences.

  5. Coevolution study of mitochondria respiratory chain proteins:Toward the understanding of protein-protein interaction

    Institute of Scientific and Technical Information of China (English)

    Ming Yang; Yan Ge; Jiayan Wu; Jingfa Xiao; Jun Yu

    2011-01-01

    Coevolution can be seen as the interdependency between evolutionary histories. In the context of protein evolution, functional correlation proteins are ever-present coordinated evolutionary characters without disruption of organismal integrity. As to complex system, there are two forms of protein-protein interactions in vivo, which refer to inter-complex interaction and intra-complex interaction. In this paper, we studied the difference of coevolution characters between inter-complex interaction and intra-complex interaction using "Mirror tree" method on the respiratory chain (RC) proteins. We divided the correlation coefficients of every pairwise RC proteins into two groups corresponding to the binary protein-protein interaction in intra-complex and the binary protein-protein interaction in inter-complex, respectively. A dramatical discrepancy is detected between the coevolution characters of the two sets of protein interactions (Wilcoxon test, p-value = 4.4 x 10-6). Our finding reveals some critical information on coevolutionary study and assists the mechanical investigation of protein-protein interaction.Furthermore, the results also provide some unique clue for supramolecular organization of protein complexes in the mitochondrial inner membrane. More detailed binding sites map and genome information of nuclear encoded RC proteins will be extraordinary valuable for the further mitochondria dynamics study.

  6. Application of Interactive Classification System in University Study Course Comparison

    Science.gov (United States)

    Birzniece, Ilze; Rudzajs, Peteris; Kalibatiene, Diana; Vasilecas, Olegas; Rencis, Edgars

    2015-01-01

    The growing amount of information in the world has increased the need for computerized classification of different objects. This situation is present in higher education as well where the possibility of effortless detection of similarity between different study courses would give the opportunity to organize student exchange programmes effectively…

  7. Interaction in a Rural Science Class. A Naturalistic Study.

    Science.gov (United States)

    Scott, Jessica P.

    The positivist paradigm has dominated the shape and direction of research in education. Traditionally the scientific method is adhered to, variables are strictly controlled, statistics are compiled, and conclusions are reached. In the post-positivist paradigm, studies conducted using naturalistic inquiry take place in the natural setting and do…

  8. A Good Statistics Study of Antiproton Interactions with Nuclei

    CERN Multimedia

    2002-01-01

    This experiment extends the study of inclusive pion production and the correlation between pions which result from hadron-nucleus collisions at intermediate and high energies to the antiproton-nucleus system. It is part of a long term systematic search for exotic nuclear phenomena. The correlation data will be used to extract, via pion interferometry, the size and coherence of the annihilation source in nuclei. In addition, the reaction @* + A @A p + A* will be studied to look for structure in the proton spectra which antiproton-nucleus bound states.\\\\ \\\\ The experimental system is based on a flexible, broad range, large acceptance (1~steradian) spectrometer which consists of an 80~cm diameter dipole magnet surrounded with detector arrays. These detectors provide momentum, energy loss, Cerenkov and time of flight information for up to ten ejectiles per event. Momentum resolution varies from 1\\% to 3\\%, depending on energy.

  9. Study of Cellulose Interaction with Concentrated Solutions of Sulfuric Acid

    OpenAIRE

    Michael Ioelovich

    2012-01-01

    The effect of the concentration of sulfuric acid (SA) and temperature on structure and properties of cellulose (MCC) had been studied. Investigations showed that solubility of the initial sample at the room temperature increased gradually in the range of the acid concentration from 50 to 60 wt.% SA. When SA concentration reached 65 wt.%, then MCC sample dissolved completely. Cellulose regenerated from 65 wt.% SA had an amorphized structure and was characterized by high enzymatic digestibility...

  10. Fundamental Studies on Droplet Interactions in Dense Sprays

    Science.gov (United States)

    1991-12-02

    high pressure conditions, the ideal gas equation of state is replaced by a Redlich - Kwong equation of state combined with mixing rules. The enthalpy of...Member, NASA Space Science and Applications Advisory Committee; Member, National Research Council Space Studies Board and Chairman, Committee on...Council for Microgravity Science and Applications . Dr. Sirignano has been involved in other research programs funded by AFWAL, AFAL, and ONR that have

  11. Magnetic properties in kagomé lattice with RKKY interaction: A Monte Carlo study

    Science.gov (United States)

    Masrour, R.; Jabar, A.; Benyoussef, A.; Hamedoun, M.

    2016-03-01

    The magnetic properties of the kagomé lattice have been studied with Ruderman-Kittel-Kasuya-Yosida (RKKY) exchange interactions in a spin-7/2 Ising model using Monte Carlo simulations. The RKKY interaction between the two magnetic layers is considered for different distances. The magnetizations and magnetic susceptibilities of this lattice are given for different triquadratic interactions around each triangular face. The critical temperature is obtained for a fixed size. The magnetic hysteresis cycle of kagomé lattice with RKKY interactions is obtained for different temperatures and for different crystal field with a fixed size of nonmagnetic layer.

  12. Interaction between Janus Green B and bovine serum albumin:Electrochemistry and spectroscopy studies

    Institute of Scientific and Technical Information of China (English)

    Neslihan (O)zdemir; Serkan (O)zdemir; Ender Bicer

    2011-01-01

    In this study, voltammetric and spectroscopic investigation of the interaction between Janus Green B (JGB) and bovine serum albumin (BSA) was reported. The interaction was observed at Britton-Robinson buffer (pH 7.0). When JGB was added to solution containing BSA, the peak currents of BSA decrease with the increasing of JGB concentrations which is due to the interaction of JGB and BSA. The binding constant of JGB with BSA was obtained by voltammetric data. Also, this interaction was supported by means of UV-vis spectroscopic measurements. The UV-vis absorption spectra of JGB in the presence of BSA decrease with the increasing of BSA concentrations.

  13. Do interactions between plant and soil biota change with elevation? A study on Fagus sylvatica.

    Science.gov (United States)

    Defossez, Emmanuel; Courbaud, Benoît; Marcais, Benoît; Thuiller, Wilfried; Granda, Elena; Kunstler, Georges

    2011-10-23

    Theoretical models predict weakening of negative biotic interactions and strengthening of positive interactions with increasing abiotic stress. However, most empirical tests have been restricted to plant-plant interactions. No empirical study has examined theoretical predictions of interactions between plants and below-ground micro-organisms, although soil biota strongly regulates plant community composition and dynamics. We examined variability in soil biota effects on tree regeneration across an abiotic gradient. Our candidate tree species was European beech (Fagus sylvatica L.), whose regeneration is extremely responsive to soil biota activity. In a greenhouse experiment, we measured tree survival in sterilized and non-sterilized soils collected across an elevation gradient in the French Alps. Negative effects of soil biota on tree survival decreased with elevation, similar to shifts observed in plant-plant interactions. Hence, soil biota effects must be included in theoretical models of plant biotic interactions to accurately represent and predict the effects of abiotic gradient on plant communities.

  14. Comparison between Free and Immobilized Ion Effects on Hydrophobic Interactions: A Molecular Dynamics Study

    CERN Document Server

    Huang, Kai; Ma, C Derek; Abbott, Nicholas L; Szlufarska, Izabela

    2016-01-01

    Fundamental studies of the effect of specific ions on hydrophobic interactions are driven by the need to understand phenomena such as hydrophobically driven self-assembly or protein folding. Using beta-peptide-inspired nano-rods, we investigate the effects of both free ions (dissolved salts) and proximally immobilized ions on hydrophobic interactions. We find that the free ion effect is correlated with the water density fluctuation near a non-polar molecular surface, showing that such fluctuation can be an indicator of hydrophobic interactions in the case of solution additives. In the case of immobilized ion, our results demonstrate that hydrophobic interactions can be switched on and off by choosing different spatial arrangements of proximal ions on a nano-rod. For globally amphiphilic nano-rods, we find that the magnitude of the interaction can be further tuned using proximal ions with varying ionic sizes. In general, univalent proximal anions are found to weaken hydrophobic interactions. This is in contras...

  15. Handheld Versus Wearable Interaction Design for Professionals - A Case Study of Hospital Service Work

    DEFF Research Database (Denmark)

    Stisen, Allan; Blunck, Henrik; Kjærgaard, Mikkel Baun;

    2014-01-01

    service work. This explorative study was conducted with 4 experienced hospital orderlies who interacted with an application across two wearable concepts, and one handheld smartphone in five scenarios in a hospital environment. The interaction was video recorded with a chest-mounted video afterwards semi...... aspects to aid designers of next generation wearable designs for hospital service work....

  16. Interactions among Future Study Abroad Students: Exploring Potential Intercultural Learning Sequences

    Science.gov (United States)

    Borghetti, C.; Beaven, A.; Pugliese, R.

    2015-01-01

    The study presented in this article aims to explore if and how intercultural learning may take place in students' class interaction. It is grounded in the assumption that interculturality is not a clear-cut feature inherent to interactions occurring when individuals with presumed different linguistic and cultural/national backgrounds talk to…

  17. Discourse as Social Interaction. Discourse Studies: A Multidisciplinary Introduction. Volume 2.

    Science.gov (United States)

    van Dijk, Teun A., Ed.

    The collection of essays on discourse as a form of social interaction includes: "Discourse as Interaction in Society" (Teun A. van Dijk); "Discourse Pragmatics" (Shoshana Blum-Kulka); "Conversation Analysis: An Approach to the Study of Social Action as Sense Making Practices" (Anita Pomerantz, B. J. Fehr); "Institutional Dialogue" (Paul Drew,…

  18. What Is Social Capital? A Study of Interaction in a Rural Community. CRLRA Discussion Paper Series.

    Science.gov (United States)

    Falk, Ian; Kilpatrick, Sue

    A case study in a rural Australian township sought to determine the nature of the interactive productivity between the local networks in a community. Participants were chosen based on recommendations of community members concerning to whom they turn for help, advice, or information. Community interactivity was recorded using interviews,…

  19. Pilot Study of Person Robot Interaction in a Public Transit Space

    DEFF Research Database (Denmark)

    Svenstrup, Mikael; Bak, Thomas; Maler, Ouri

    2009-01-01

    This paper describes a study of the effect of a human interactive robot placed in an urban transit space. The underlying hypothesis is that it is possible to create interesting new living spaces and induce value in terms of experiences, information or economics, by putting socially interactive...

  20. Studying Activities That Take Place in Speech Interactions: A Theoretical and Methodological Framework

    Science.gov (United States)

    Saint-Dizier de Almeida, Valérie; Colletta, Jean-Marc; Auriac-Slusarczyk, Emmanuelle; Specogna, Antonietta; Simon, Jean-Pascal; Fiema, Gabriela; Luxembourger, Christophe

    2016-01-01

    The paper proposes a theoretical and methodological framework based on a pluralistic, concerted approach to the study of activities that take place in and through speech interactions. The framework has a general scope, applying to any collective activity taking form through language interactions. It contributes to a fuller understanding of the…

  1. Transcription factors do it together : the hows and whys of studying protein-protein interactions

    NARCIS (Netherlands)

    Immink, R.G.H.; Angenent, G.C.

    2002-01-01

    Protein–protein interactions are intrinsic to virtually every cellular process. Recent breakthroughs in techniques to study protein-interaction and the availability of fully sequenced plant genomes have attracted many plant scientists to undertake the first steps in the field of protein

  2. A Voice-Activated, Interactive Videodisc Case Study for Use in the Medical School Classroom.

    Science.gov (United States)

    Harless, William G.; And Others

    1986-01-01

    The Technological Innovations in Medical Education (TIME) Project of the Lister Hill National Center for Biomedical Communications is exploring the use of interactive videodisc, microcomputer, and voice recognition technology to create interactive case studies of simulated patients to train second-year medical students in the introduction to…

  3. Repair Sequences in Dysarthric Conversational Speech: A Study in Interactional Phonetics

    Science.gov (United States)

    Rutter, Ben

    2009-01-01

    This paper presents some findings from a case study of repair sequences in conversations between a dysarthric speaker, Chris, and her interactional partners. It adopts the methodology of interactional phonetics, where turn design, sequence organization, and variation in phonetic parameters are analysed in unison. The analysis focused on the use of…

  4. Online Learning across Ethnicity and Age: A Study on Learning Interaction Participation, Perception, and Learning Satisfaction

    Science.gov (United States)

    Ke, Fengfeng; Kwak, Dean

    2013-01-01

    This mixed-method study examined whether online learning interaction participation, perception, and learning satisfaction would be consistent across varied age and ethnicity groups. Data were collected from students enrolled in 28 online courses via content analysis with online interaction transcripts, structural equation modeling with the…

  5. A Study of Multimodal Discourse in the Design of Interactive Digital Material for Language Learning

    Science.gov (United States)

    Burset, Silvia; Bosch, Emma; Pujolà, Joan-Tomàs

    2016-01-01

    This study analyses some published interactive materials for the learning of Spanish as a f?irst language and English as a Foreign Language (EFL) commonly used in primary and secondary education in Spain. The present investigation looks into the relationships between text and image on the interface of Interactive Digital Material (IDM) to develop…

  6. A Voice-Activated, Interactive Videodisc Case Study for Use in the Medical School Classroom.

    Science.gov (United States)

    Harless, William G.; And Others

    1986-01-01

    The Technological Innovations in Medical Education (TIME) Project of the Lister Hill National Center for Biomedical Communications is exploring the use of interactive videodisc, microcomputer, and voice recognition technology to create interactive case studies of simulated patients to train second-year medical students in the introduction to…

  7. Interactive Radio Counseling in Indira Gandhi National Open University: A Study.

    Science.gov (United States)

    Chaudhary, Sohanvir S.; Bansal, Kiron

    2000-01-01

    Explains interactive radio as an effective tool for open and distance learning provided it is planned, designed, implemented, and monitored systematically. Describes the interactive radio counseling at Indira Gandhi National Open University (IGNOU) that provides support to students who study print material and may attend weekend…

  8. Description of alpha-nucleus interaction cross sections for cosmic ray shielding studies

    Science.gov (United States)

    Cucinotta, Francis A.; Townsend, Lawrence W.; Wilson, John W.

    1993-01-01

    Nuclear interactions of high-energy alpha particles with target nuclei important for cosmic ray studies are discussed. Models for elastic, quasi-elastic, and breakup reactions are presented and compared with experimental data. Energy-dependent interaction cross sections and secondary spectra are presented based on theoretical models and the limited experimental data base.

  9. Repair Sequences in Dysarthric Conversational Speech: A Study in Interactional Phonetics

    Science.gov (United States)

    Rutter, Ben

    2009-01-01

    This paper presents some findings from a case study of repair sequences in conversations between a dysarthric speaker, Chris, and her interactional partners. It adopts the methodology of interactional phonetics, where turn design, sequence organization, and variation in phonetic parameters are analysed in unison. The analysis focused on the use of…

  10. Quality Standards Matter: A Comparative Case Study Examining Interactive Writing in the Preschool Setting

    Science.gov (United States)

    Hall, Anna H.

    2017-01-01

    Interactive writing is a research-based early literacy strategy that has been found effective at increasing young children's oral language skills, alphabet knowledge, phonemic awareness, concepts of print, and early writing skills. This paper reports on a case study which explored the feasibility and fidelity of implementing interactive writing in…

  11. Increasing International and Domestic Student Interaction through Group Work: A Case Study from the Humanities

    Science.gov (United States)

    Cruickshank, Ken; Chen, Honglin; Warren, Stan

    2012-01-01

    This article explores the use of group work strategies to increase student interaction and learning. Despite the growing linguistic and cultural diversity in tertiary institutions, there is strong evidence of minimal interaction between "domestic" and "international" students in classrooms and in wider university contexts. This study investigates…

  12. Progress of Large-Scale Air-Sea Interaction Studies in China

    Institute of Scientific and Technical Information of China (English)

    蒲书箴; 赵进平; 于卫东; 赵永平; 杨波

    2004-01-01

    This paper summarizes the progress of large-scale air-sea interaction studies that has been achieved in China in the four-year period from July 1998 to July 2002, including seven aspects in the area of the air-sea interaction, namely air-sea interaction related to the tropical Pacific Ocean, monsoon-related air-sea interaction, air-sea interaction in the north Pacific Ocean, air-sea interaction in the Indian Ocean, air-sea interactions in the global oceans, field experiments, and oceanic cruise surveys. However more attention has been paid to the first and the second aspects because a large number of papers in the reference literature for preparing and organizing this paper are concentrated in the tropical Pacific Ocean, such as the ENSO process with its climatic effects and dynamics, and the monsoon-related air-sea interaction. The literature also involves various phenomena with their different time and spatial scales such as intraseasonal, annual, interannual, and interdecadal variabilities in the atmosphere/ocean interaction system, reflecting the contemporary themes in the four-year period at the beginning of an era from the post-TOGA to CLIVAR studies. Apparently, it is a difficult task to summarize the great progress in this area, as it is extracted from a large quantity of literature, although the authors tried very hard.

  13. New Mexico Center for Particle Physics: Studies of fundamental interactions

    Energy Technology Data Exchange (ETDEWEB)

    Matthews, J.A.J.

    1992-01-01

    The New Mexico Center/UNM group research program includes the CDF experiment at Fermilab and the SDC experiment at the SSC. In both experiments the UNM group research focuses on silicon strip tracking systems. The present research goals are to develop and utilize precision silicon tracking to increase significantly the physics reach of the Tevatron, and to make possible the study of high-P[sub t] physics at the SSC. The search for the t-quark in CDF is the primary goal of the upcoming Tevatron runs. This Progress Report summarizes our research accomplishments from the last year.

  14. Calorimetric study of benzaldehyde interaction with acetic anhydride

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, A.M.; Ivanova, L.A.

    1978-03-01

    Benzaldehyde conversion to benzylidene diacetate, a side reaction reducing the selectivity of benzaldehyde oxidation to acetylbenzoyl peroxide, studied at 6/sup 0/-50/sup 0/C, was an irreversible third-order reaction catalyzed by beryllium sulfate or by succinnic, chloroacetic, and particularly sulfuric and perchloric acids. In the presence of organic solvents, (e.g., benzene, hexane, or cyclohexane), the process was complicated by acidolysis and parallel C-acylation reactions, and the catalyst rapidly deactivated. A microcalorimetric method was developed to determine kinetic parameters of the process in the absence of the solvents. Tables and graphs.

  15. Environmental Pricing: Studies in Policy Choices and Interactions

    DEFF Research Database (Denmark)

    areas of current practice that must be addressed. Empirical studies of policy strategies are discussed to illustrate the extent to which current climate change policy is integrated against the proposed successful policy combinations that are presented in this insightful book. Environmental pricing......Environmental taxes can be efficient tools for successful environmental policy. Their use, however, has been limited in many countries. This thoughtful book explores the scope of environmental pricing and examines a variety of national experiences in environmental policy integration, to identify...

  16. Parental Interaction Patterns in Children with Adhd and Controls; a Comparative Study

    Directory of Open Access Journals (Sweden)

    M Afkhami -Aghda

    2007-04-01

    Full Text Available Introduction: Communicational patterns of the parents can either positively or negatively influence children's personality. Parenting manner has long-term effects on behavior, function, expectations and eventually people's future personality. This study investigates parental interaction patterns in children with attention deficit- hyperactive disorder. Methods :In this study, 50 male children aged 7-12 years were selected in two groups including 1 25 students with ADHD referring to psychiatry clinics in Isfahan according to the diagnostic scale of DSM- IV and 2 25 healthy boys selected by random cluster multistage sampling from primary schools in five districts of Isfahan from Septamber 2005 until March 2005. Schaffer and Edgerton parental interaction questionnaire was filled for them. Results: In "Communication" interaction pattern, the mean score of healthy children was 15.08, while the mean score of ADHD children was 13.42. In "admission" interactional pattern; the mean of the first group was 14.76, while the second group was 11.76. In "control" interactional pattern, mean of group one was 13.28 and the second group was 11.76. In "aggression control" interactional pattern, the mean of group one was 13 and the second group was 14.68. In "lack of aggressive attachment" interactional pattern, mean of the first group was 13.36 and the second group was 16.67. The mean scores of parental interactional pattern in healthy children were all higher than ADHD children except for "aggression control" and "lack of aggressive attachment" interactional patterns. Conclusion: The more the parental "admission" interactional pattern score, the lower the signs of ADHD in children. The signs of severity are lower in cases with more positive parental "control" interactional patterns. If the scores of "lack of aggressive/ attachment" and "aggressive/ control" interactional patterns are higher, ADHD signs are more severe.

  17. Interaction of metaiodobenzylguanidine with cardioactive drugs: an in vitro study

    Energy Technology Data Exchange (ETDEWEB)

    Huguet, F. [INSERM, Tours Univ. Hospital (France)]|[Inst. of Xenobiotic Studies, Poitiers Univ. Hospital (France); Fagret, D. [URA, CNRS, Grenoble Univ. Hospital (France); Caillet, M. [INSERM, Tours Univ. Hospital (France); Piriou, A. [Inst. of Xenobiotic Studies, Poitiers Univ. Hospital (France); Besnard, J.C. [INSERM, Tours Univ. Hospital (France); Guilloteau, D. [INSERM, Tours Univ. Hospital (France)

    1996-05-01

    Metaiodobenzylguanidine (MIBG), an analogue of noradrenaline, is used to explore the functional integrity of sympathetic nerve endings in the human heart. Various drugs inhibit noradrenaline transport systems and may block the uptake of MIBG. As in vivo studies of the effect of these drugs on myocardial [{sup 123}]MIBG uptake are often difficult to perform, we used an in vitro human blood platelet model for this purpose. A platelet preparation from healthy volunteers was incubated with [{sup 125}I]MIBG alone or different concentrations of drugs currently used in cardiology. Labetalol and propranolol inhibited [{sup 125}I]MIGB uptake, whereas all other drugs tested (other {beta}-blockers, calcium inhibitors, digoxin and amiodarone) had no effecft even at doses exceeding 50 {mu}M. The labetalol dose inhibiting 50% of [{sup 125}I]MIBG uptake was lower than the plasma concentration of this drug in treated patients, whereas the propranolol dose was higher. This in vitro study of the effect of drugs on MIBG uptake by human blood platelets is predictive of their in vivo effect on myocardial uptake of [{sup 123}I]MIBG in treated patients, provided that plasma concentration is taken into account. (orig.)

  18. Wave-Structure Interactions on Point Absorbers - an experimental study

    DEFF Research Database (Denmark)

    Jakobsen, Morten Møller

    used in the case studies is a pitching point absorber (Wavestar). The central part of the thesis deals with the challenges, choices, and experi- ences gained during the Ph.D. The more in-depth technical details and results are presented in peer-reviewed publications and technical reports. The chal...... models. Using a modification by Faltinsen to take into account the relative motion of the device, the contributions from drag, excitation and body motion are determined. 2: Determining the peak pressure on the surface on the device during extreme events and in freak conditions. A great deal of work has...... been done to determine peak pressures on mono-piles worldwide, but only very little on spherical structures. In order to shed more light on the wave induced loads on a hemisphere the peak pressures are measured with the traditional drop test and during impact of so-called freak waves. 3: Implementation...

  19. Interaction Study of Guest with Host in Clathrate Hydrate

    Institute of Scientific and Technical Information of China (English)

    Lin Wang; Shunle Dong

    2007-01-01

    Lattice dynamical simulations of noble gas hydrate structures I and II have been performed. Potential energies were investigated to study the influence of guest species on the stability of the hydrate structure. Results show that when the diameter of inclusion molecules is between 3 A and 4.2 A, such as Ar and Kr, the critical role of the 512 cage in the stabilization of hydrates becomes effective. For Xe hydrates SI and SII, with the help of lattice dynamical calculations, the modes attributions are identified directly. We proposed the resonant effect of the fingerprint frequency at about 7 meV and 10 meV which arise from the coupling of Xe molecules in the 512 cage with the host lattice.

  20. An Interactive Zoo Guide: A Case Study of Collaborative Learning

    CERN Document Server

    Shi, Hao

    2010-01-01

    Real Industry Projects and team work can have a great impact on student learning but providing these activities requires significant commitment from academics. It requires several years planning implementing to create a collaborative learning environment that mimics the real world ICT (Information and Communication Technology) industry workplace. In this project, staff from all the three faculties, namely the Faculty of Health, Engineering and Science, Faculty of Arts, Education and Human Development, and Faculty of Business and Law in higher education work together to establish a detailed project management plan and to develop the unit guidelines for participating students. The proposed project brings together students from business, multimedia and computer science degrees studying their three project-based units within each faculty to work on a relatively large IT project with our industry partner, Melbourne Zoo. This paper presents one multimedia software project accomplished by one of the multi-discipline...

  1. The properties of genome conformation and spatial gene interaction and regulation networks of normal and malignant human cell types.

    Directory of Open Access Journals (Sweden)

    Zheng Wang

    Full Text Available The spatial conformation of a genome plays an important role in the long-range regulation of genome-wide gene expression and methylation, but has not been extensively studied due to lack of genome conformation data. The recently developed chromosome conformation capturing techniques such as the Hi-C method empowered by next generation sequencing can generate unbiased, large-scale, high-resolution chromosomal interaction (contact data, providing an unprecedented opportunity to investigate the spatial structure of a genome and its applications in gene regulation, genomics, epigenetics, and cell biology. In this work, we conducted a comprehensive, large-scale computational analysis of this new stream of genome conformation data generated for three different human leukemia cells or cell lines by the Hi-C technique. We developed and applied a set of bioinformatics methods to reliably generate spatial chromosomal contacts from high-throughput sequencing data and to effectively use them to study the properties of the genome structures in one-dimension (1D and two-dimension (2D. Our analysis demonstrates that Hi-C data can be effectively applied to study tissue-specific genome conformation, chromosome-chromosome interaction, chromosomal translocations, and spatial gene-gene interaction and regulation in a three-dimensional genome of primary tumor cells. Particularly, for the first time, we constructed genome-scale spatial gene-gene interaction network, transcription factor binding site (TFBS - TFBS interaction network, and TFBS-gene interaction network from chromosomal contact information. Remarkably, all these networks possess the properties of scale-free modular networks.

  2. Drug-DNA interactions and their study by UV-Visible, fluorescence spectroscopies and cyclic voltametry.

    Science.gov (United States)

    Sirajuddin, Muhammad; Ali, Saqib; Badshah, Amin

    2013-07-05

    The present paper review the drug-DNA interactions, their types and applications of experimental techniques used to study interactions between DNA and small ligand molecules that are potentially of pharmaceutical interest. DNA has been known to be the cellular target for many cytotoxic anticancer agents for several decades. Understanding how drug molecules interact with DNA has become an active research area at the interface between chemistry, molecular biology and medicine. In this review article, we attempt to bring together topics that cover the breadth of this large area of research. The interaction of drugs with DNA is a significant feature in pharmacology and plays a vital role in the determination of the mechanisms of drug action and designing of more efficient and specifically targeted drugs with lesser side effects. Several instrumental techniques are used to study such interactions. In the present review, we will discuss UV-Visible spectroscopy, fluorescence spectroscopy and cyclic voltammetry. The applications of spectroscopic techniques are reviewed and we have discussed the type of information (qualitative or quantitative) that can be obtained from the use of each technique. Not only have novel techniques been applied to study drug-DNA interactions but such interactions may also be the basis for the development of new assays. The interaction between DNA and drugs can cause chemical and conformational modifications and, thus, variation of the electrochemical properties of nucleobases.

  3. Study of Electroweak Interactions at the Energy Frontier

    CERN Document Server

    Baak, M; Bodek, A; Caputo, R; Corbett, T; Degrande, C; Eboli, O; Erler, J; Feigl, B; Freitas, A; Fraile, J Gonzalez; Gonzalez-Garcia, M C; Haller, J; Han, J; Heinemeyer, S; Hoecker, A; Holzbauer, J L; Hsu, S -C; Jaeger, B; Janot, P; Kilian, W; Kogler, R; Kotwal, A; Langacker, P; Li, S; Linssen, L; Marx, M; Mattelaer, O; Metcalfe, J; Monig, K; Moortgat-Pick, G; Pleier, M -A; Pollard, C; Ramsey-Musolf, M; Rauch, M; Reuter, J; Rojo, J; Rominsky, M; Sakumoto, W; Schott, M; Schwinn, C; Sekulla, M; Stelzer, J; Torrence, E; Vicini, A; Wackeroth, D; Weiglein, G; Wilson, G; Zeune, L

    2013-01-01

    With the discovery of the Higgs boson, the spectrum of particles in the Standard Model (SM) is complete. It is more important than ever to perform precision measurements and to test for deviations from SM predictions in the electroweak sector. In this report, we investigate two themes in the arena of precision electroweak measurements: the electroweak precision observables (EWPOs) that test the particle content and couplings in the SM and the minimal supersymmetric SM, and the measurements involving multiple gauge bosons in the final state which provide unique probes of the basic tenets of electroweak symmetry breaking. Among the important EWPOs we focus our discussion on M_W and sin^2 theta_eff^l, and on anomalous quartic gauge couplings probed by triboson production and vector boson scattering. We investigate the thresholds of precision that need to be achieved in order to be sensitive to new physics. We study the precision that can be achieved at various facilities on these observables. We discuss the calc...

  4. Study of surfactant-skin interactions by skin impedance measurements.

    Science.gov (United States)

    Lu, Guojin; Moore, David J

    2012-02-01

    The stratum corneum (SC) plays a very critical physiological role as skin barrier in regulating water loss through the skin and protects the body from a wide range of physical and chemical exogenous insults. Surfactant-containing formulations can induce skin damage and irritation owing to surfactant absorption and penetration. It is generally accepted that reduction in skin barrier properties occurs only after surfactants have penetrated/permeated into the skin barrier. To mitigate the harshness of surfactant-based cleansing products, penetration/permeation of surfactants should be reduced. Skin impedance measurements have been taken in vitro on porcine skin using vertical Franz diffusion cells to investigate the impact of surfactants, temperature and pH on skin barrier integrity. These skin impedance results demonstrate excellent correlation with other published methods for assessing skin damage and irritation from different surfactant chemistry, concentration, pH, time of exposure and temperature. This study demonstrates that skin impedance can be utilized as a routine approach to screen surfactant-containing formulations for their propensity to compromise the skin barrier and hence likely lead to skin irritation.

  5. Statistical and Thermodynamical Studies of the Strongly Interacting Matter

    CERN Document Server

    Horváth, Miklós

    2016-01-01

    In this thesis we discuss three separate analysis of various phenomenological aspects of heavy-ion collisions (HIC). The first one is a possible generalization of the kinetic theory framework for dense systems. We investigate its long-time behaviour and the properties of the equilibrium. The second discussion is about the phenomenological analysis of the azimuthal asymmetry of the particle yields in a HIC, where we link the initial stage geometrical asymmetry to the particle yields and examine the possible organizing mechanisms that could be responsible for such a relation. The third, and also the most thorough part of the thesis is about the relation of the spectral density of quasi-particle states and the macroscopic fluidity measure (the ratio of shear viscosity and the entropy density) and other transport properties of the system. We extensively study the liquid-gas crossover with the help of model spectral functions. The main conclusion is that the relative intensification of the continuum of the scatter...

  6. Cognitive conflict in human-automation interactions: a psychophysiological study.

    Science.gov (United States)

    Dehais, Frédéric; Causse, Mickaël; Vachon, François; Tremblay, Sébastien

    2012-05-01

    The review of literature in sociology and distributed artificial intelligence reveals that the occurrence of conflict is a remarkable precursor to the disruption of multi-agent systems. The study of this concept could be applied to human factors concerns, as man-system conflict appears to provoke perseveration behavior and to degrade attentional abilities with a trend to excessive focus. Once entangled in such conflicts, the human operator will do anything to succeed in his current goal even if it jeopardizes the mission. In order to confirm these findings, an experimental setup, composed of a real unmanned ground vehicle, a ground station is developed. A scenario involving an authority conflict between the participants and the robot is proposed. Analysis of the effects of the conflict on the participants' cognition and arousal is assessed through heart-rate measurement (reflecting stress level) and eye-tracking techniques (index of attentional focus). Our results clearly show that the occurrence of the conflict leads to perseveration behavior and can induce higher heart rate as well as excessive attentional focus. These results are discussed in terms of task commitment issues and increased arousal. Moreover, our results suggest that individual differences may predict susceptibility to perseveration behavior.

  7. Multimodal Study of Adult-Infant Interaction: A Review of Its Origins and Its Current Status

    Directory of Open Access Journals (Sweden)

    Soledad Carretero Pérez

    Full Text Available Abstract An interpretative review of research on adult-infant interactions involving the analysis of movement behaviors is presented, systematically linking previous studies to current research on the subject. Forty-two articles analyzing the dyad's interactive movement in the period 1970-2015 were found. Twelve papers were excluded, including only those that studied the phenomenon in the baby's first year of life. The results revealed that movement was a central topic in early interaction studies in the 70s. In the 1980's and 1990's, its study was marginal and it is currently resurging under the embodiment perspective. The conceptual framework and research methods used in the pioneering work are presented, and the thematic foci shared with current research are highlighted. Thus, essential keys are provided for the updated study of early interactions from a multimodal perspective.

  8. Higher Order Inclusion Complexes and Secondary Interactions Studied by Global Analysis of Calorimetric Titrations

    DEFF Research Database (Denmark)

    Schönbeck, Jens Christian Sidney; Holm, René; Westh, Peter

    2012-01-01

    ). The results are validated by a 13C NMR titration and negative controls with a bile salt with no secondary binding site (glycocholate) (K = 2.96 ± 0.01 × 103 M–1). The method proved useful for detailed analysis of ITC data and may strengthen its use as a tool for studying molecular systems by advanced binding......This paper investigates the use of isothermal titration calorimetry (ITC) as a tool for studying molecular systems in which weaker secondary interactions are present in addition to a dominant primary interaction. Such systems are challenging since the signal pertaining to the stronger primary...... interaction tends to overshadow the signal from the secondary interaction. The methodology presented here enables a complete and precise thermodynamic characterization of both the primary and the weaker secondary interaction, exemplified by the binding of β-cyclodextrin to the primary and secondary binding...

  9. Experimental study of Human Adenoviruses interactions with clays

    Science.gov (United States)

    Bellou, Maria; Syngouna, Vasiliki; Paparrodopoulos, Spyros; Vantarakis, Apostolos; Chrysikopoulos, Constantinos

    2014-05-01

    Clays are used to establish low permeability liners in landfills, sewage lagoons, water retention ponds, golf course ponds, and hazardous waste sites. Human adenoviruses (HAdVs) are waterborne viruses which have been used as viral indicators of fecal pollution. The objective of this study was to investigate the survival of HAdV in static and dynamic clay systems. The clays used as a model were crystalline aluminosilicates: kaolinite and bentonite. The adsorption and survival of HAdVs onto these clays were characterized at two different controlled temperatures (4 and 25o C) under static and dynamic batch conditions. Control tubes, in the absence of clay, were used to monitor virus inactivation due to factors other than adsorption to clays (e.g. inactivation or sorption onto the tubes walls). For both static and dynamic batch experiments, samples were collected for a maximum period of seven days. This seven day time - period was determined to be sufficient for the virus-clay systems to reach equilibrium. To infer the presence of infectious HAdV particles, all samples were treated with Dnase and the extraction of viral nucleid acid was performed using a commercial viral RNA kit. All samples were analyzed by Real - Time PCR which was used to quantify viral particles in clays. Samples were also tested for virus infectivity by A549 cell cultures. Exposure time intervals in the range of seven days (0.50-144 hours) resulted in a load reduction of 0.74 to 2.96 logs for kaolinite and a reduction of 0.89 to 2.92 for bentonite. Furthermore, virus survival was higher onto bentonite than kaolinite (p

  10. Laboratory Studies of Sea-Ice-Wave Interactions

    Science.gov (United States)

    Monty, J.; Meylan, M. H.; Babanin, A. V.; Toffoli, A.; Bennetts, L.

    2016-12-01

    A world-first facility for studying the Marginal Ice Zone has been constructed in the Michell Hydrodynamics Laboratory at the University of Melbourne. A 14m long wave tank (0.75m wide, 0.6m deep) resides in a freezer, where air temperature can be controlled down to -15C. This permits the freezing of the water surface. Large stainless steel ice-making trays (up to 4 m long) are also available to create ice of desired thickness and microstructure, which can be lowered onto the water surface. A computer controlled wave generator is capable of creating waves of any desired form. The temperature of the water in the tank can also be controlled between 2 and 30C. The tank frame is constructed of marine-treated wood and the entire tank is glass and acrylic, permitting the use of corrosive fluids, such as salt water. Here we present the first laboratory experiments of break-up of a controlled thickness, fresh water ice sheet impacted by regular and JONSWAP spectrum surface waves. The geometry of the resultant ice-floes is measured with high-resolution, time-resolved imaging, providing the crucial data of floe size distribution. Initial observations show that, in the case of high steepness waves, the primary mechanisms of ice break-up at the ice edge are overwash and rafting, both of which put weight on the ice interior to the ice-water interface. This additional weight (and impact in the case of rafting) breaks more ice, which allows overwash and rafting deeper into the ice sheet, breaking more ice and so on. For lower steepness waves, overwash and rafting are still present but far less significant. Finally, results of vertical ice movement using laser height gauges will be presented showing the attenuation of waves into an ice sheet and through a pack of ice floes. These results are compared with field data and theory available (e.g. Squire & Moore, Nature, 1980 and Kohout et al., Nature, 2014).

  11. An exploratory study of the interaction between work and personal life: Experiences of South African employees

    Directory of Open Access Journals (Sweden)

    Eileen Koekemoer

    2010-03-01

    Full Text Available Orientation: The interaction between work and personal life is an important field of research in the 21st century and of pressing concern for various individuals and organisations internationally and in South Africa.Research purpose: The objective of this study was to investigate the interaction between work and personal life and the experiences thereof in the South African context.Motivation of the study: South African employees are faced with various circumstances which could influence the interaction between their work and personal life and which could constitute different/unique experiences regarding this interaction.Research design, approach and method: A non-probability purposive voluntary sample was used. Data collection was done by means of semi-structured in-depth interviews with 92 participants. Content analysis was used to analyse and interpret the research data.Main findings: Four main themes (i.e. the experience of work, experiences and domains in the personal life, interaction between work and personal life, consequences associated with the interaction were extracted from the data. Participants indicated stressful and supportive aspects in their work as well as additional personal dimensions in their personal life. Interaction between work and various personal dimensions were indicated, as well as consequences associated with different types of interaction.Practical and managerial implications: Individuals experienced interaction between their work and various other personal dimensions, where the forms of interaction were associated with certain consequences (i.e. spillover of emotions, energy depletion.Contribution/value-add: Compared to international findings, unique findings were obtained relating to individuals’ personal life and the consequences associated with the interaction.

  12. Characteristics of the interaction of azulene with water and hydrogen sulfide: A computational study.

    Science.gov (United States)

    Cabaleiro-Lago, Enrique M; Rodríguez-Otero, Jesús; Peña-Gallego, Angeles

    2008-08-28

    A computational study was carried out for studying the characteristics of the interaction between azulene and water or hydrogen sulfide. In azulene...water complex the water molecule is located with both hydrogen atoms pointing toward the aromatic cloud but displaced to the five-membered ring. Hydrogen sulfide adopts a similar arrangement but located roughly over the central C-C bond of azulene. Calculations show that hydrogen sulfide interacts with azulene more strongly (-4.19 kcal/mol) than water (-3.76 kcal/mol), although this is only revealed at the highest levels of calculation. The nature of the interaction is electrostatic and dispersive in the same percentage for water cluster, whereas for hydrogen sulfide dispersion is the dominant contribution. Clusters containing two water molecules are controlled by the possibility of establishing an O-H...O hydrogen bond. As a consequence, the most stable structure corresponds to the interaction between a water dimer and azulene, with an interaction energy amounting to -11.77 kcal/mol. Hydrogen sulfide interaction is stronger with azulene than with itself, so structures with S-H...S contact and others, where H(2)S only interacts with azulene, present similar interaction energies (-8.02 kcal/mol for the most stable one).

  13. Quantum Monte Carlo study of strange correlator in interacting topological insulators

    Science.gov (United States)

    Wu, Han-Qing; He, Yuan-Yao; You, Yi-Zhuang; Xu, Cenke; Meng, Zi Yang; Lu, Zhong-Yi

    Distinguishing the nontrivial symmetry-protected topological (SPT) phase from the trivial insulator phase in the presence of electron-electron interaction is an urgent question to the study of topological insulators. In this work, we demonstrate that the strange correlator is a sensitive diagnosis to detect SPT states in interacting systems. Employing large-scale quantum Monte Carlo (QMC) simulations, we investigate the interaction-driven quantum phase transition in the Kane-Mele-Hubbard model. The transition from the quantum spin Hall insulator at weak interaction to an antiferromagnetic Mott insulator at strong interaction can be readily detected by the momentum space behavior of the strange correlator in single-particle, spin, and pairing sectors. The interaction e?ects on the symmetry-protected edge states in various sectors are well captured in the QMC measurements of strange correlators. Moreover, we demonstrate that the strange correlator is technically easier to implement in QMC and more robust in performance than other proposed numerical diagnoses for interacting topological states, as only static correlations are needed. The attempt in this work paves the way for using the strange correlator to study interaction-driven topological phase transitions.

  14. A molecular-genetic approach to studying source-sink interactions in Arabidopsis thalian. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Gibson, S. I.

    2000-06-01

    This is a final report describing the results of the research funded by the DOE Energy Biosciences Program grant entitled ''A Molecular-Genetic Approach to Studying Source-Sink Interactions in Arabidiopsis thaliana''.

  15. Studies in Interactive Techniques and Systems for Reconstruction of Fleet Exercise.

    Science.gov (United States)

    general performance, design, development and test requirements study for the Fleet Analysis and Reconstruction of Exercise Facility (FAREF); and research and testing of interactive techniques and computer algorithms . (Author)

  16. Research-practice interactions as reported in recent design studies: Still promising, still hazy

    NARCIS (Netherlands)

    Ormel, Bart; Pareja Roblin, Natalie; McKenney, Susan

    2012-01-01

    Ormel, B., Pareja, N., & McKenney, S. (2011, 8-10 June). Research-practice interactions as reported in recent design studies: Still promising, still hazy. Paper presentation at the ORD annual meeting, Maastricht.

  17. Exercising autonomous learning approaches through interactive notebooks: a qualitative case study

    National Research Council Canada - National Science Library

    Jaladanki, Vani S; Bhattacharya, Kakali

    2014-01-01

    ... using interactive notebooks to inform students' understanding of physics concepts. The participant for the study was purposefully selected with an intention to gain an in-depth understanding of the experiences...

  18. Translating evidence-based guidelines to improve feedback practices: the interACT case study

    National Research Council Canada - National Science Library

    Barton, Karen L; Schofield, Susie J; McAleer, Sean; Ajjawi, Rola

    2016-01-01

    ...'. The aim of this paper is to present a case study demonstrating how an entire programme's assessment and feedback practices were re-engineered and evaluated in line with evidence from the literature in the interACT...

  19. Research-practice interactions as reported in recent design studies: Still promising, still hazy

    NARCIS (Netherlands)

    Ormel, Bart; Pareja Roblin, Natalie; McKenney, Susan

    2012-01-01

    Ormel, B., Pareja, N., & McKenney, S. (2011, 8-10 June). Research-practice interactions as reported in recent design studies: Still promising, still hazy. Paper presentation at the ORD annual meeting, Maastricht.

  20. Homogalacturonan deesterification during pollen-ovule interaction in Larix decidua Mill.: an immunocytochemical study.

    Science.gov (United States)

    Rafińska, Katarzyna; Świdziński, Michał; Bednarska-Kozakiewicz, Elżbieta

    2014-07-01

    Studies on angiosperm plants have shown that homogalacturonan present in the extracellular matrix of pistils plays an important role in the interaction with the male gametophyte. However, in gymnosperms, knowledge on the participation of HG in the pollen-ovule interaction is limited, and only a few studies on male gametophytes have been reported. Thus, the aim of this study was to determine the distribution of HG in male gametophytes and ovules during their interaction in Larix decidua Mill. The distribution of HG in pollen grains and unpollinated and pollinated ovules was investigated by immunofluorescence techniques using monoclonal antibodies that recognise high methyl-esterified HG (JIM7), low methyl-esterified HG (JIM5) and calcium cross-linked HG (2F4). All studied categories of HG were detected in the ovule. Highly methyl-esterified HG was present in the cell walls of all cells throughout the interaction; however, the distribution of low methyl-esterified and calcium cross-linked HG changed during the course of interaction. Both of these categories of HG appeared only in the apoplast and the extracellular matrix of the ovule tissues, which interact with the male gametophyte. This finding suggests that in L. decidua, low methyl-esterified and calcium cross-linked HG play an important role in pollen-ovule interaction. The last category of HG is most likely involved in adhesion between the pollen and the ovule and might provide an optimal calcium environment for pollen grain germination and pollen tube growth.

  1. Alcohol-related breast cancer in postmenopausal women - effect of CYP19A1, PPARG and PPARGC1A polymorphisms on female sex-hormone levels and interaction with alcohol consumption and NSAID usage in a nested case-control study and a randomised controlled trial

    DEFF Research Database (Denmark)

    Kopp, Tine Iskov; Jensen, Ditte Marie; Ravn-Haren, Gitte;

    2016-01-01

    19A1 is associated with risk of BC in a case-control study group nested within the Danish "Diet, Cancer and Health" cohort (ncases = 687 and ncontrols = 687) and searched for gene-gene interaction between CYP19A1 and PPARGC1A, and CYP19A1 and PPARG, and gene-alcohol and gene-NSAID interactions......Alcohol consumption is associated with increased risk of breast cancer (BC), and the underlying mechanism is thought to be sex-hormone driven. In vitro and observational studies suggest a mechanism involving peroxisome proliferator-activated receptor gamma (PPARγ) in a complex with peroxisome...... and the PPARγ stimulator Ibuprofen on sex-hormone levels following alcohol intake in postmenopausal women (n = 25) using linear regression. Genetic variations in CYP19A1 were associated with hormone levels (estrone: P rs11070844 = 0.009, estrone sulphate: P rs11070844 = 0.01, P rs749292 = 0.004, P rs1062033 = 0...

  2. A weighted AMMI Algorithm to Study Genotype-by-Environment Interaction and QTL-by-Environment Interaction

    NARCIS (Netherlands)

    Rodrigues, P.C.; Malosetti, M.; Gauch, H.G.

    2014-01-01

    Genotype-by-environment (G × E) interaction (GEI) and quantitative trait locus (QTL)-by-environment interaction (QEI) are common phenomena in multiple-environment trials and represent a major challenge to breeders. The additive main effects and multiplicative interaction (AMMI) model is a widely use

  3. A Human Work Interaction Design (HWID) Case Study in E-Government and Public Information Systems

    DEFF Research Database (Denmark)

    Clemmensen, Torkil

    2011-01-01

    This paper first outlines a revised version of the general HWID framework, with a focus on what connects empirical work analysis and interaction design, and then presents a case study of the Danish government one-for-all authentication system NemID. The case is briefly analyzed, using...... ethnomethodology, work domain/task analysis, and the HWID approach, and comparing the results. Compared to the traditional approaches, the HWID focus on case-specific connections between human work and interaction design, gives different and supplementary answers. The conclusion is that there are benefits...... in studying how human work analysis and interaction design in concrete cases are related and connected....

  4. Effect of exchange interaction in ferromagnetic superlattices: A Monte Carlo study

    Science.gov (United States)

    Masrour, R.; Jabar, A.

    2016-10-01

    The Monte Carlo simulation is used to investigate the magnetic properties of ferromagnetic superlattices through the Ising model. The reduced critical temperatures of the ferromagnetic superlattices are studied each as a function of layer thickness for different values of exchange interaction. The exchange interaction in each layer within the interface and the crystal field in the unit cell are studied. The magnetic coercive fields and magnetization remnants are obtained for different values of exchange interaction, different values of temperature and crystal field with fixed values of physical parameters.

  5. Reasons and strategies associated with positive interaction between work and home amongst managers: An exploratory study

    Directory of Open Access Journals (Sweden)

    Janet Oosthuizen

    2010-03-01

    Full Text Available Orientation: In order to facilitate positive interaction between work and home, it is necessary to understand the reasons for and strategies used by managerial employees to manage this interaction.Research purpose: The objectives of this study were to determine, (1 reasons why employees experience high or low positive work–home interaction and (2 strategies that employees with high and low positive interaction use.Motivation for the study: Positive interaction between work and home, particularly in managerial employees, is becoming increasingly more important with a view to ensuring a stable and healthy work–home life.Research design, approach and method: A random clustered sample (n = 275 was taken from managerial employees in a multinational organisation and the Survey Work–Home Interaction-Nijmegen (SWING was administered to identify participants with high and low positive interaction between work and home respectively. Thereafter, exploratory qualitative interviews were conducted with selected participants (n = 32 to deduce themes for the above-mentioned objectives. Content analysis was used to analyse, quantify and interpret the research data.Main findings: Reasons for high or low positive interaction were identified in conjunction with previous research. Ten successful strategies for positive interaction between work and home were identified and reported.Managerial/practical implications: Organisational recommendations made include changing the organisational culture to being more supportive, developing employees for future positions and creating social networks. In addition, individual strategies and recommendations for future research are identified.Contribution/value-add: This study contributes to the limited research on strategies for positive interaction between work and home among managerial employees.

  6. Global Positioning Systems (GPS) Technology to Study Vector-Pathogen-Host Interactions

    Science.gov (United States)

    2016-12-01

    Award Number: W81XWH-11-2-0175 TITLE: Global Positioning Systems ( GPS ) Technology to Study Vector-Pathogen-Host Interactions PRINCIPAL...Positioning Systems ( GPS ) Technology to Study Vector-Pathogen-Host Interactions 5b. GRANT NUMBER W81XWH-11-2-0175 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S...sophisticated Global Positioning Systems ( GPS ) technology of isolated viruses and genetic characterization, spatial and temporal analysis are being

  7. A Study of User's Performance and Satisfaction on the Web Based Photo Annotation with Speech Interaction

    CERN Document Server

    Ramlan, Siti Azura

    2010-01-01

    This paper reports on empirical evaluation study of users' performance and satisfaction with prototype of Web Based speech photo annotation with speech interaction. Participants involved consist of Johor Bahru citizens from various background. They have completed two parts of annotation task; part A involving PhotoASys; photo annotation system with proposed speech interaction and part B involving Microsoft Microsoft Vista Speech Interaction style. They have completed eight tasks for each part including system login and selection of album and photos. Users' performance was recorded using computer screen recording software. Data were captured on the task completion time and subjective satisfaction. Participants need to complete a questionnaire on the subjective satisfaction when the task was completed. The performance data show the comparison between proposed speech interaction and Microsoft Vista Speech interaction applied in photo annotation system, PhotoASys. On average, the reduction in annotation performan...

  8. On the interactions of leflunomide and teriflunomide within receptor cavity--NMR studies and energy calculations.

    Science.gov (United States)

    Kujawski, Jacek; Bernard, Marek K; Jodłowska, Elżbieta; Czaja, Kornelia; Drabińska, Beata

    2015-05-01

    Leflunomide is a disease-modifying antirheumatic drug with antiinflammatory and immunosuppressive activity used for the treatment of psoriatic and rheumatoid arthritis. It undergoes rapid metabolization to teriflunomide, a metabolite that is responsible for the biological activity of leflunomide. Continuing our investigations on the interactions of biologically important azahetarenes with the environment, we focused on leflunomide and its active metabolite, teriflunomide, considering the interactions teriflunomide-amino acid within the target protein (dihydroorotate dehydrogenase) using density functional theory, as well as ONIOM techniques. The results of theoretical studies have shown that the interactions of teriflunomide with tyrosine and arginine involve principally the amide fragment of teriflunomide. The presence of the internal hydrogen bond between (Z)-teriflunomide carbonyl oxygen and enolic hydroxyl decreases the interaction strength between teriflunomide and tyrosine or arginine. Even the E isomer of teriflunomide would usually provide a stronger interaction teriflunomide-amino acid than the Z isomer with the internal hydrogen bond.

  9. Reactivity of chitosan derivatives and their interaction with guanine: A computational study

    Indian Academy of Sciences (India)

    Bhabesh Chandra Deka; Pradip Kr Bhattacharyya

    2016-04-01

    The present study delves into the reactivity of a few chitosan derivatives (CSDs) and their interaction with guanine in vacuum and in different phases. Increase in the polarity of the solvent lowers reactivity of the chosen derivatives (evaluated by using reactivity descriptors). Interaction between the CSDs and guanine (measured by interaction energy) weakens in solvent media and CSD-guanine interaction is weaker than the interaction between guanine and unmodified chitosan (CS). Chemical stability of CSD-guanine adducts remains similar to that of CS-guanine adduct in both polar and non-polar media. Moreover, CSD-guanine adducts exhibit comparable thermodynamic stability (quantified by free energy of solvation, Gsol) to that of unmodified CS-guanine adduct in non-polar solvent but in polar medium they are immensely destabilized in comparison to CS-guanine adduct. Observed theoretical results are expected to provide guidance for future relevant experimental research on gene delivery by CS derivatives.

  10. Atomic Force Microscopy Study of the Interactions of Indolicidin with Model Membranes and DNA.

    Science.gov (United States)

    Fojan, Peter; Gurevich, Leonid

    2017-01-01

    The cell membrane is the first barrier and quite often the primary target that antimicrobial peptides (AMPs) have to destroy or penetrate to fulfill their mission. Upon penetrating through the membrane, the peptides can further attack intracellular targets, in particular DNA. Studying the interaction of an antimicrobial peptide with a cell membrane and DNA holds keys to understanding its killing mechanisms. Commonly, these interactions are studied by using optical or scanning electron microscopy and appropriately labeled peptides. However, labeling can significantly affect the hydrophobicity, conformation, and size of the peptide, hence altering the interaction significantly. Here, we describe the use of atomic force microscopy (AFM) for a label-free study of the interactions of peptides with model membranes under physiological conditions and DNA as a possible intracellular target.

  11. Amphiphilic naproxen prodrugs: differential scanning calorimetry study on their interaction with phospholipid bilayers.

    Science.gov (United States)

    Giuffrida, Maria Chiara; Pignatello, Rosario; Castelli, Francesco; Sarpietro, Maria Grazia

    2017-09-01

    Naproxen, a nonsteroid anti-inflammatory drug studied for Alzheimer's disease, was conjugated with lipoamino acids (LAA) directly or through a diethylamine (EDA) spacer to improve the drug lipophilicity and the interaction with phospholipid bilayers. The interaction of naproxen and its prodrugs with biomembrane models consisting of dimyristoylphosphatidylcholine multilamellar vesicles was studied by differential scanning calorimetry. The transfer of prodrugs from a lipophilic carrier to a biomembrane model was also studied. Naproxen conjugation to lipoamino acids improves its interaction with biomembrane models and affects the transfer from a lipophilic carrier to biomembrane model. LAA portion may localize between the phospholipid chains; the entity of the interaction depends not only on the presence of the spacer but also on the LAA chain length. Variation of LAA portion can modulate the naproxen prodrugs affinity towards the biological membrane as well as towards the lipophilic carrier. © 2017 Royal Pharmaceutical Society.

  12. Computational study of the interaction of indole-like molecules with water and hydrogen sulfide.

    Science.gov (United States)

    Cabaleiro-Lago, Enrique M; Rodríguez-Otero, Jesús; Peña-Gallego, Ángeles

    2011-10-01

    The characteristics of the interaction between water and hydrogen sulfide with indole and a series of analogs obtained by substituting the NH group of indole by different heteroatoms have been studied by means of ab initio calculations. In all cases, minima were found corresponding to structures where water and hydrogen sulfide interact by means of X-H···π contacts. The interaction energies for all these π complexes are quite similar, spanning from -13.5 to -18.8 kJ/mol, and exhibiting the stability sequence NH > CH(2) ≈ PH > Se ≈ S > O, for both water and hydrogen sulfide. Though interaction energies are similar, hydrogen sulfide complexes are slightly favored over their water counterparts when interacting with the π cloud. σ-Type complexes were also considered for the systems studied, but only in the case of water complexes this kind of complexes is relevant. Only for complexes formed by water and indole, a significantly more stable σ-type complex was found with an interaction energy amounting to -23.6 kJ/mol. Oxygen and phosphorous derivatives also form σ-type complexes of similar stability as that observed for π ones. Despite the similar interaction energies exhibited by complexes with water and hydrogen sulfide, the nature of the interaction is very different. For π complexes with water the main contributions to the interaction energy are electrostatic and dispersive contributing with similar amounts, though slightly more from electrostatics. On the contrary, in hydrogen sulfide complexes dispersion is by far the main stabilizing contribution. For the σ-type complexes, the interaction is clearly dominated by the electrostatic contribution, especially in the indole-water complex.

  13. Computational study of the interaction of indole-like molecules with water and hydrogen sulfide

    Science.gov (United States)

    Cabaleiro-Lago, Enrique M.; Rodríguez-Otero, Jesús; Peña-Gallego, Ángeles

    2011-10-01

    The characteristics of the interaction between water and hydrogen sulfide with indole and a series of analogs obtained by substituting the NH group of indole by different heteroatoms have been studied by means of ab initio calculations. In all cases, minima were found corresponding to structures where water and hydrogen sulfide interact by means of X-H...π contacts. The interaction energies for all these π complexes are quite similar, spanning from -13.5 to -18.8 kJ/mol, and exhibiting the stability sequence NH > CH2 ≈ PH > Se ≈ S > O, for both water and hydrogen sulfide. Though interaction energies are similar, hydrogen sulfide complexes are slightly favored over their water counterparts when interacting with the π cloud. σ-Type complexes were also considered for the systems studied, but only in the case of water complexes this kind of complexes is relevant. Only for complexes formed by water and indole, a significantly more stable σ-type complex was found with an interaction energy amounting to -23.6 kJ/mol. Oxygen and phosphorous derivatives also form σ-type complexes of similar stability as that observed for π ones. Despite the similar interaction energies exhibited by complexes with water and hydrogen sulfide, the nature of the interaction is very different. For π complexes with water the main contributions to the interaction energy are electrostatic and dispersive contributing with similar amounts, though slightly more from electrostatics. On the contrary, in hydrogen sulfide complexes dispersion is by far the main stabilizing contribution. For the σ-type complexes, the interaction is clearly dominated by the electrostatic contribution, especially in the indole-water complex.

  14. PHASE INTERACTION BETWEEN EEG RHYTHMS IN THE STUDY OF PROCESSES OF TIME PERCEPTION

    Directory of Open Access Journals (Sweden)

    Yu. V. Bushov

    2014-01-01

    Full Text Available The present study pursued to investigate the role of phase interactions between EEG rhythms in the process of the perception of time. The purpose of the study was to analyse the dependence of these interactions on the type and stage of the activity being performed, as well as on the individual characteristics of a human. For this purpose, 27 boys and 29 girls, all university students, were asked to reproduce and measure short intervals of time (200 and 800 ms, during which their EEG was recorded in frontal, central, parietal, temporal, and occipital lobes, according to the system 10–20%. While studying phase interactions between EEG rhythms, we used wavelet bispectral analysis and calculated the bicoherence function. As it follows from the conducted research, most often close phase interactions are observed between the gamma-rhythm and other rhythms of EEG or between different frequencies of the gamma-rhythm. It was established that the phase interactions under study were influenced by the factors of “sex”, “activity type”, and “activity stage”. The study showed correlations of phase interactions with the levels of intellect, extraversion, neuroticism, with the particularities of the lateral organisation of brain, and the accuracy of time perception.

  15. A microcalorimetric study of molecular interactions between immunoglobulin G and hydrophobic charge-induction ligand.

    Science.gov (United States)

    Yuan, Xiao-Ming; Lin, Dong-Qiang; Zhang, Qi-Lei; Gao, Dong; Yao, Shan-Jing

    2016-04-22

    Hydrophobic charge-induction chromatography (HCIC) with 4-mercaptoethyl-pyridine (MEP) as the ligand is a novel technology for antibody purification. In this study, isothermal titration calorimetry (ITC) was used to evaluate the molecular interactions between MEP ligand and immunoglobulin G (IgG). Three types of IgG molecules including human IgG (hIgG), bovine IgG (bIgG) and a monoclonal antibody (mAb) were investigated with human serum albumins (HSA) and bovine serum albumin (BSA) as the comparison. The thermodynamic parameters obtained from ITC were compared with the adsorption data. The results indicated that MEP binding to protein at neutral pH was entropy driven and induced by multimodal molecular interactions that was dominated by hydrophobic forces. The interactions between MEP and IgGs were stronger than that of albumins, which resulted in high binding affinity of IgGs. Moreover, the effects of pH and salt addition on MEP-hIgG binding were studied. The change of enthalpy increased obviously with the decrease of pH, which revealed that the electrostatic forces dominated the MEP-hIgG interactions at acidic condition and caused typical charge-induced elution of HCIC. Salt addition influenced both hydrophobic and electrostatic interactions. With the increase of salt concentration, the hydrophobic interactions decreased first and then increased, while the electrostatic interactions showed the opposite trend. This resulted in trade-off between the multimodal interactions, which caused the salt-tolerant property of MEP resin. In general, ITC studies revealed the molecular mechanism of three critical characteristics of HCIC, multimodal interactions, pH-dependent and salt-tolerant properties.

  16. Testing for mechanistic interactions in long-term follow-up studies.

    Directory of Open Access Journals (Sweden)

    Jui-Hsiang Lin

    Full Text Available In follow-up studies, interactions are often assessed by including a cross-product term in a (multiplicative Cox model. However, epidemiologists/clinicians often misinterpret a significant multiplicative interaction as a genuine mechanistic interaction. Though indices specific to mechanistic interactions have been proposed, including the 'relative excess risk due to interaction' (RERI and the 'peril ratio index of synergy based on multiplicativity' (PRISM, these indices assume no loss to follow up and no competing death in a study. In this paper, the authors propose a novel 'mechanistic interaction test' (MIT for censored data. Monte-Carlo simulation shows that when the hazard curves are proportional to, non-proportional to, or even crossing over one another, the proposed MIT can maintain reasonably accurate type I error rates for censored data. It has far greater powers than the modified RERI and PRISM tests (modified for censored data scenarios. To test mechanistic interactions in censored data, we recommend using MIT in light of its desirable statistical properties.

  17. Key Considerations and Methods in the Study of Gene-Environment Interactions.

    Science.gov (United States)

    Simon, Paul H G; Sylvestre, Marie-Pierre; Tremblay, Johanne; Hamet, Pavel

    2016-08-01

    With increased involvement of genetic data in most epidemiological investigations, gene-environment (G × E) interactions now stand as a topic, which must be meticulously assessed and thoroughly understood. The level, mode, and outcomes of interactions between environmental factors and genetic traits have the capacity to modulate disease risk. These must, therefore, be carefully evaluated as they have the potential to offer novel insights on the "missing heritability problem", reaching beyond our current limitations. First, we review a definition of G × E interactions. We then explore how concepts such as the early manifestation of the genetic components of a disease, the heterogeneity of complex traits, the clear definition of epidemiological strata, and the effect of varying physiological conditions can affect our capacity to detect (or miss) G × E interactions. Lastly, we discuss the shortfalls of regression models to study G × E interactions and how other methods such as the ReliefF algorithm, pattern recognition methods, or the LASSO (Least Absolute Shrinkage and Selection Operator) method can enable us to more adequately model G × E interactions. Overall, we present the elements to consider and a path to follow when studying genetic determinants of disease in order to uncover potential G × E interactions.

  18. Drug – Excipient interaction studies of loperamide loaded in polsorbate 80 liposomes.

    Directory of Open Access Journals (Sweden)

    I. Sarath Chandran

    2015-12-01

    Full Text Available Drug – delivery interaction studies were done for lopermide(Lp loaded surfactant liposomes (LpLc using FTIR ,DSC , XRD and SEM. Early researches have used Lp and liposomes for brain targeting programme but not have done any interaction studies .We have investigated presence of any drug degradative interactions with the excipient ( drug delivery – Liposomes using FTIR , DSC , XRD and SEM analytical techniques. Our results suggests that presence of characteristic IR absorption peaks of Lp in LpLc in FTIR study confirmed absence of any drug interactions. Absence of Drug endothermic peak in DSC of LpLc indicates the amorphous nature of entrapped Lp . SEM ensured the absence of any undissolved drug or particles. XRD supports the existence of Lp in the LpLc without any drug interaction. In conclusion , drug loperamide (Lp does not showed any degradative interactions with the carrier or excipient. Thus these studies supports the safety and efficient usage of Liposomes for Lp .

  19. Acetaminophen interacts with human hemoglobin: optical, physical and molecular modeling studies.

    Science.gov (United States)

    Seal, Paromita; Sikdar, Jyotirmoy; Roy, Amartya; Haldar, Rajen

    2017-05-01

    Acetaminophen, a widely used analgesic and antipyretic drug has ample affinity to bind globular proteins. Here, we have illustrated a substantive study pertaining to the interaction of acetaminophen with human hemoglobin (HHb). Different spectroscopic (absorption, fluorescence, and circular dichroism (CD) spectroscopy), calorimetric, and molecular docking techniques have been employed in this study. Acetaminophen-induced graded alterations in absorbance and fluorescence of HHb confirm their interaction. Analysis of fluorescence quenching at different temperature and data obtained from isothermal titration calorimetry indicate that the interaction is static and the HHb has one binding site for the drug. The negative values of Gibbs energy change (ΔG(0)) and enthalpy changes (ΔH(0)) and positive value of entropy change (ΔS(0)) strongly suggest that it is entropy-driven spontaneous and exothermic reaction. The reaction involves hydrophobic pocket of the protein which is further stabilized by hydrogen bonding as evidenced from ANS and sucrose binding studies. These findings were also supported by molecular docking simulation study using AutoDock 4.2. The interaction influences structural integrity as well as functional properties of HHb as evidenced by CD spectroscopy, increased rate of co-oxidation and decreased esterase activity of HHb. So, from these findings, we may conclude that acetaminophen interacts with HHb through hydrophobic and hydrogen bonding, and the interaction perturbs the structural and functional properties of HHb.

  20. STUDY OF INTERACTION OF DRUGS WITH BODY-ALIKE MACROMOLECULE (POLYVINYLPYRROLIDONE BY ULTRA VIOLET SPECTROSCOPIC METHOD

    Directory of Open Access Journals (Sweden)

    AKHTAR SAEED

    2006-01-01

    Full Text Available UV-visible spectrophotometric technique was used to study the interaction of polyvinylpyrrolidone (PVP with co-solutes: phenol, benzoic acid, sodium benzoate, salicylic acid and acetyl salicylic acid in aqueous medium. Changes in the absorption spectra of the co-solutes were observed in the presence of PVP from 200 to 210 nm. The changes were attributed to interaction of PVP molecules with the co-solute molecules. As the concentration of the co-solute increased, a red shift in the bands was observed indicating an increase in interaction between PVP and the co-solute.

  1. Peer Interaction and Writing Development in a Social Studies High School Classroom

    Science.gov (United States)

    Berridge, Erik

    2009-01-01

    Peer review can be a valuable tool in the writing development of high school sophomores. Specifically, this research study explores the use of peer review to improve writing skills and to build content knowledge in a social studies high school classroom through the use of peer interaction. The problem in social studies high school instruction is…

  2. Retrospective analysis of main and interaction effects in genetic association studies of human complex traits

    DEFF Research Database (Denmark)

    Tan, Qihua; Christiansen, Lene; Brasch-Andersen, Charlotte;

    2007-01-01

    BACKGROUND: The etiology of multifactorial human diseases involves complex interactions between numerous environmental factors and alleles of many genes. Efficient statistical tools are demanded in identifying the genetic and environmental variants that affect the risk of disease development....... This paper introduces a retrospective polytomous logistic regression model to measure both the main and interaction effects in genetic association studies of human discrete and continuous complex traits. In this model, combinations of genotypes at two interacting loci or of environmental exposure...... regression model can be used as a convenient tool for assessing both main and interaction effects in genetic association studies of human multifactorial diseases involving genetic and non-genetic factors as well as categorical or continuous traits....

  3. A theoretical study of adsorbate-adsorbate interactions on Ru(0001)

    DEFF Research Database (Denmark)

    Mortensen, Jens Jørgen; Hammer, Bjørk; Nørskov, Jens Kehlet

    1998-01-01

    Using density functional theory we study the effect of pre-adsorbed atoms on the dissociation of N(2) and the adsorption of N, N(2), and CO on Ru(0001). We have done calculations for pre-adsorbed Na, Cs, and S, and find that alkali atoms adsorbed close to a dissociating N(2) molecule will lower...... the barrier for dissociation, whereas S will increase it. The interaction with alkali atoms is mainly of an electrostatic nature. The poisoning by S is due to two kinds of repulsive interactions: a Pauli repulsion and a reduced covalent bond strength between the adsorbate and the surface d-electrons. In order...... to investigate these different interactions in more detail, we look at three different species (N atoms, and terminally bonded N(2) and CO) and use them as probes to study their interaction with two modifier atoms (Na and S). The two modifier atoms have very different properties, which allows us to decouple...

  4. Molecular interactions of proteins and peptides at interfaces studied by sum frequency generation vibrational spectroscopy.

    Science.gov (United States)

    Liu, Yuwei; Jasensky, Joshua; Chen, Zhan

    2012-01-31

    Interfacial peptides and proteins are critical in many biological processes and thus are of interest to various research fields. To study these processes, surface sensitive techniques are required to completely describe different interfacial interactions intrinsic to many complicated processes. Sum frequency generation (SFG) spectroscopy has been developed into a powerful tool to investigate these interactions and mechanisms of a variety of interfacial peptides and proteins. It has been shown that SFG has intrinsic surface sensitivity and the ability to acquire conformation, orientation, and ordering information about these systems. This paper reviews recent studies on peptide/protein-substrate interactions, peptide/protein-membrane interactions, and protein complexes at interfaces and demonstrates the ability of SFG on unveiling the molecular pictures of complicated interfacial biological processes. © 2011 American Chemical Society

  5. Interaction between γ-aminobutyric acid A receptor genes: new evidence in migraine susceptibility.

    Directory of Open Access Journals (Sweden)

    Marlene Quintas

    Full Text Available Migraine is a common neurological episodic disorder with a female-to-male prevalence 3- to 4-fold higher, suggesting a possible X-linked genetic component. Our aims were to assess the role of common variants of gamma-aminobutyric acid A receptor (GABAAR genes, located in the X-chromosome, in migraine susceptibility and the possible interaction between them. An association study with 188 unrelated cases and 286 migraine-free controls age- and ethnic matched was performed. Twenty-three tagging SNPs were selected in three genes (GABRE, GABRA3 and GABRQ. Allelic, genotypic and haplotypic frequencies were compared between cases and controls. We also focused on gene-gene interactions. The AT genotype of rs3810651 of GABRQ gene was associated with an increased risk for migraine (OR: 4.07; 95% CI: 1.71-9.73, p=0.002, while the CT genotype of rs3902802 (OR: 0.41; 95% CI: 0.21-0.78, p=0.006 and GA genotype of rs2131190 of GABRA3 gene (OR: 0.53; 95% CI: 0.32-0.88, p=0.013 seem to be protective factors. All associations were found in the female group and maintained significance after Bonferroni correction. We also found three nominal associations in the allelic analyses although there were no significant results in the haplotypic analyses. Strikingly, we found strong interactions between six SNPs encoding for different subunits of GABAAR, all significant after permutation correction. To our knowledge, we show for the first time, the putative involvement of polymorphisms in GABAAR genes in migraine susceptibility and more importantly we unraveled a role for novel gene-gene interactions opening new perspectives for the development of more effective treatments.

  6. Studies of $\\Lambda n$ interaction through polarization observables for final-state interactions in exclusive $\\Lambda$ photoproduction off the deuteron

    Energy Technology Data Exchange (ETDEWEB)

    Ilieva, Yordanka [Univ. of South Carolina, Columbia, SC (United States); Cao, Tongtong [Univ. of South Carolina, Columbia, SC (United States); Zachariou, Nicholas [Univ. of Edinburgh, Scotland (United Kingdom)

    2016-06-01

    Theoretical studies suggest that experimental observables for hyperon production reactions can place stringent constraints on the free parameters of hyperon-nucleon potentials, which are critical for the understanding of hypernuclear matter and neutron stars. Here we present preliminary experimental results for the polarization observables S, Py, Ox, Oz, Cx, and Cz for final-state interactions (FSI) in exclusive L photoproduction off the deuteron. The observables were obtained from data collected during the E06-103 (g13) experiment with the CEBAF Large Acceptance Spectrometer (CLAS) in Hall B at Jefferson Lab. The g13 experiment ran with unpolarized deuteron target and circularly- and linearly-polarized photon beams with energies between 0.5 GeV and 2.5 GeV and collected about 51010 events with multiple charged particles in the final state. To select the reaction of interest, the K+ and the L decay products, a proton and a negative pion, were detected in the CLAS. The missing-mass technique was used to identify exclusive hyperon photoproduction events. Final-state interaction events were selected by requesting that the reconstructed neutron has a momentum larger than 200 MeV/c. The large statistics of E06-103 provided statistically meaningful FSI event samples, which allow for the extraction of one- and two-fold differential single- and double-polarization observables. Here we present preliminary results for a set of six observables for photon energies between 0.9 GeV and 2.3 GeV and for several kinematic variables in the Ln center-of-mass frame. Our results are the very first estimates of polarization observables for FSI in hyperon photoproduction and will be used to constrain the free parameters of hyperon-nucleon potentials.

  7. A qualitative study of police interactions as perceived by people living with mental disorder

    OpenAIRE

    2014-01-01

    Police officers are often the first responders to individuals in crises. Understanding the dynamic interaction between police and persons living with mental illness is critical to developing interventions and appropriate services for this population. Using procedural justice theory, this study involves a qualitative thematic analysis of interviews conducted with 60 people living with mental illness regarding their interactions with police officers. The results indicate that common factors ...

  8. Molecular Dynamics Simulation Study on the Carbon Nanotube Interacting with a Polymer

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Leton C.; Mian, Shabeer A.; Jang, Joon Kyung [Pusan National University, Busan (Korea, Republic of)

    2012-03-15

    Using molecular dynamics simulation method, we studied the carbon nanotube (CNT) non-covalently interacting with a polymer. As the polymer coiled around the CNT, the diameter of CNT deformed by more than 40% of its original value within 50 ps. By considering three different polymers, we conclude that the interaction between the CNT and polymer is governed by the number of repeating units in the polymer, not by the molecular weight of polymer

  9. A Monte Carlo study of temperature-programmed desorption spectra with attractive lateral interactions

    CERN Document Server

    Jansen, A P J

    1995-01-01

    We present results of a Monte Carlo study of temperature-programmed desorption in a model system with attractive lateral interactions. It is shown that even for weak interactions there are large shifts of the peak maximum temperatures with initial coverage. The system has a transition temperature below which the desorption has a negative order. An analytical expression for this temperature is derived. The relation between the model and real systems is discussed.

  10. Impact of Interaction Between PPAR Alpha and PPAR Gamma on Breast Cancer Risk in the Chinese Han Population.

    Science.gov (United States)

    Lianggeng, Xiong; Baiwu, Liang; Maoshu, Bai; Jiming, Liu; Youshan, Li

    2017-08-01

    Several studies have been conducted to investigate the association of the peroxisome proliferator-activated receptor (PPAR) alpha (PPAR A) and PPAR gamma (PPAR G) polymorphism and breast cancer (BC) risk, but the results were inconsistent, and, until now, no study focused on the impact of gene-gene interactions between PPAR A and PPAR G on BC risk; thus, the aim of this study was to investigate the impact of interaction between PPAR A and PPAR G on BC risk in the Chinese Han population. A total of 862 participants with a mean age of 63.0 ± 15.7 years were selected, including 432 patients with BC and 430 controls. A logistic regression model was used to examine the association between single-nucleotide polymorphisms and BC risk. The odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated. Generalized multifactor dimensionality reduction was employed to analyze the gene-gene interaction. Logistic regression analysis showed that BC risk was significantly higher in carriers of G allele of rs1800206 polymorphism than those with CC (CG + GG vs. CC) (adjusted OR, 1.50; 95% CI, 1.20-1.93). In addition, we found that BC risk was also significantly higher in carriers of the G allele of the rs1805192 polymorphism than those with the CC genotype (CG + GG vs. CC) (adjusted OR, 1.78; 95% CI, 1.34-2.26). There was a significant gene-gene interaction between rs1805192 and rs1800206. Overall, the 2-locus models had a cross-validation consistency of 10 of 10, and had a testing accuracy of 60.11%. Patients with CG or GG of rs1805192 and CG or GG of rs1800206 genotype have the highest BC risk, compared with patients with CC of rs1805192 and CC of rs1800206 genotype (OR, 2.59; 95% CI, 1.70-3.48, after covariates adjustment for gender, age, age at menarche, number of children, body mass index, and waist circumference). The minor allele of rs1800206 and rs1805192 and its interaction were associated with increased BC risk. Copyright © 2016 Elsevier Inc. All rights

  11. A Modified Adaptive Lasso for Identifying Interactions in the Cox Model with the Heredity Constraint.

    Science.gov (United States)

    Wang, Lu; Shen, Jincheng; Thall, Peter F

    2014-10-01

    In many biomedical studies, identifying effects of covariate interactions on survival is a major goal. Important examples are treatment-subgroup interactions in clinical trials, and gene-gene or gene-environment interactions in genomic studies. A common problem when implementing a variable selection algorithm in such settings is the requirement that the model must satisfy the strong heredity constraint, wherein an interaction may be included in the model only if the interaction's component variables are included as main effects. We propose a modified Lasso method for the Cox regression model that adaptively selects important single covariates and pairwise interactions while enforcing the strong heredity constraint. The proposed method is based on a modified log partial likelihood including two adaptively weighted penalties, one for main effects and one for interactions. A two-dimensional tuning parameter for the penalties is determined by generalized cross-validation. Asymptotic properties are established, including consistency and rate of convergence, and it is shown that the proposed selection procedure has oracle properties, given proper choice of regularization parameters. Simulations illustrate that the proposed method performs reliably across a range of different scenarios.

  12. Case-control studies of gene-environment interaction: Bayesian design and analysis.

    Science.gov (United States)

    Mukherjee, Bhramar; Ahn, Jaeil; Gruber, Stephen B; Ghosh, Malay; Chatterjee, Nilanjan

    2010-09-01

    With increasing frequency, epidemiologic studies are addressing hypotheses regarding gene-environment interaction. In many well-studied candidate genes and for standard dietary and behavioral epidemiologic exposures, there is often substantial prior information available that may be used to analyze current data as well as for designing a new study. In this article, first, we propose a proper full Bayesian approach for analyzing studies of gene-environment interaction. The Bayesian approach provides a natural way to incorporate uncertainties around the assumption of gene-environment independence, often used in such an analysis. We then consider Bayesian sample size determination criteria for both estimation and hypothesis testing regarding the multiplicative gene-environment interaction parameter. We illustrate our proposed methods using data from a large ongoing case-control study of colorectal cancer investigating the interaction of N-acetyl transferase type 2 (NAT2) with smoking and red meat consumption. We use the existing data to elicit a design prior and show how to use this information in allocating cases and controls in planning a future study that investigates the same interaction parameters. The Bayesian design and analysis strategies are compared with their corresponding frequentist counterparts.

  13. Structural Analysis of DNA Interactions with Magnesium Ion Studied by Raman Spectroscopy

    Directory of Open Access Journals (Sweden)

    S. Ponkumar

    2011-01-01

    Full Text Available Problem statement: In the present study, FT Raman spectroscopy had been used to extend our knowledge about Magnesium ion - DNA interactions at various volume ratios (1:50, 1:20, 1:10 and 1:5. Approach: The analysis of FT Raman data supported the existence of structural specificities in the interaction and also the stability of DNA secondary structure. Results: Results from the Raman spectra clearly indicate that the interaction of Magnesium ion with DNA is mainly through the phosphate groups of DNA with negligible change of the B-conformation of DNA at all the volume ratios studied. For example, band at 1079 cm-1 assigned to the symmetrical stretching vibration of the nucleic acid phosphodioxy (PO-2 group. This band in the order 1079¨ 1075¨ 1070¨ 1066¨ 1063 cm-1 at all Magnesium ion DNA concentrations studied. Similarly, Raman band at 845 cm-1 due to antisymmetrical phosphodiester (O-P-O stretching of DNA. Conclusion: Magnesium ion interaction with the DNA phosphate is weak in comparison to interactions with the bases. On the other hand, the Raman signature of B-DNA is largely unperturbed by magnesium ion, suggesting much weaker interactions.

  14. CHRNA7 Polymorphisms and Dementia Risk: Interactions with Apolipoprotein ε4 and Cigarette Smoking.

    Science.gov (United States)

    Weng, Pei-Hsuan; Chen, Jen-Hau; Chen, Ta-Fu; Sun, Yu; Wen, Li-Li; Yip, Ping-Keung; Chu, Yi-Min; Chen, Yen-Ching

    2016-06-02

    α7 nicotinic acetylcholine receptor (α7nAChR, encoded by CHRNA7) is involved in dementia pathogenesis through cholinergic neurotransmission, neuroprotection and interactions with amyloid-β. Smoking promotes atherosclerosis and increases dementia risk, but nicotine exerts neuroprotective effect via α7nAChR in preclinical studies. No studies explored the gene-gene, gene-environment interactions between CHRNA7 polymorphism, apolipoprotein E (APOE) ε4 status and smoking on dementia risk. This case-control study recruited 254 late-onset Alzheimer's disease (LOAD) and 115 vascular dementia (VaD) cases (age ≥65) from the neurology clinics of three teaching hospitals in Taiwan during 2007-2010. Controls (N = 435) were recruited from health checkup programs and volunteers during the same period. Nine CHRNA7 haplotype-tagging single nucleotide polymorphisms representative for Taiwanese were genotyped. Among APOE ε4 non-carriers, CHRNA7 rs7179008 variant carriers had significantly decreased LOAD risk after correction for multiple tests (GG + AG vs. AA: adjusted odds ratio = 0.29, 95% confidence interval = 0.13-0.64, P = 0.002). Similar findings were observed for carriers of GT haplotype in CHRNA7 block4. A significant interaction was found between rs7179008, GT haplotype in block4 and APOE ε4 on LOAD risk. rs7179008 variant also reduced the detrimental effect of smoking on LOAD risk. No significant association was found between CHRNA7 and VaD. These findings help to understand dementia pathogenesis.

  15. Bimolecular fluorescence complementation as a tool to study interactions of regulatory proteins in plant protoplasts.

    Science.gov (United States)

    Pattanaik, Sitakanta; Werkman, Joshua R; Yuan, Ling

    2011-01-01

    Protein-protein interactions are an important aspect of the gene regulation process. The expression of a gene in response to certain stimuli, within a specific cell type or at a particular developmental stage, involves a complex network of interactions between different regulatory proteins and the cis-regulatory elements present in the promoter of the gene. A number of methods have been developed to study protein-protein interactions in vitro and in vivo in plant cells, one of which is bimolecular fluorescence complementation (BiFC). BiFC is a relatively simple technique based upon the reconstitution of a fluorescent protein. The interacting protein complex can be visualized directly in a living plant cell when two non-fluorescent fragments, of an otherwise fluorescent protein, are fused to proteins found within that complex. Interaction of tagged proteins brings the two non-fluorescent fragments into close proximity and reconstitutes the fluorescent protein. In addition, the subcellular location of an interacting protein complex in the cell can be simultaneously determined. Using this approach, we have successfully demonstrated a protein-protein interaction between a R2R3 MYB and a basic helix-loop-helix MYC transcription factor related to flavonoid biosynthetic pathway in tobacco protoplasts.

  16. A computational study of the protein-ligand interactions in CDK2 inhibitors: using quantum mechanics/molecular mechanics interaction energy as a predictor of the biological activity.

    Science.gov (United States)

    Alzate-Morales, Jans H; Contreras, Renato; Soriano, Alejandro; Tuñon, Iñaki; Silla, Estanislao

    2007-01-15

    We report a combined quantum mechanics/molecular mechanics (QM/MM) study to determine the protein-ligand interaction energy between CDK2 (cyclin-dependent kinase 2) and five inhibitors with the N(2)-substituted 6-cyclohexyl-methoxy-purine scaffold. The computational results in this work show that the QM/MM interaction energy is strongly correlated to the biological activity and can be used as a predictor, at least within a family of substrates. A detailed analysis of the protein-ligand structures obtained from molecular dynamics simulations shows specific interactions within the active site that, in some cases, have not been reported before to our knowledge. The computed interaction energy gauges the strength of protein-ligand interactions. Finally, energy decomposition and multiple regression analyses were performed to check the contribution of the electrostatic and van der Waals energies to the total interaction energy and to show the capabilities of the computational model to identify new potent inhibitors.

  17. Etudes sociales 30. Sujet B: Interaction entre nations. Cahier de l'eleve. Edition finale = Social Studies 30. Subject B: Interaction between Nations. Student Workbook. Final Edition.

    Science.gov (United States)

    Alberta Dept. of Education, Edmonton. Curriculum Branch.

    In this Alberta (Canada) student workbook, four history units are presented for study. These are: (1) Between Two Wars (1919-1936); (2) World War II; (3) The Emergence and Interaction of the Superpowers; and (4) Contemporary World Interactions. Advice is offered to students in each unit along with information about key events and issues during…

  18. Theoretical and computational studies of the interactions between small nanoparticles and with aqueous environments

    Science.gov (United States)

    Villarreal, Oscar D.

    Interactions between nanoparticles (metallic, biological or a hybrid mix of the two) in aqueous solutions can have multiple biological applications. In some of them their tendency towards aggregation can be desirable (e.g. self-assembly), while in others it may impact negatively on their reliability (e.g. drug delivery). A realistic model of these systems contains about a million or more degrees of freedom, but their study has become feasible with today's high performance computing. In particular, nanoparticles of a few nanometers in size interacting at sub-nanometer distances have become a novel area of research. The standard mean-field model of colloid science, the Derjaguin-Landau-Verwey-Overbeak (DLVO) theory, and even the extended version (XDLVO) have encountered multiple challenges when attempting to understand the interactions of small nanoparticles in the short range, since assumptions of continuous effects no longer apply. Because the region of the interaction is in the angstrom scale, the effects of atomic finite sizes and unique entropic interactions cannot be described through simple analytical formulae corresponding to generalized interaction potentials. In this work, all-atom molecular dynamics simulations have been performed on small nanoparticles in order to provide a theoretical background for their interactions with various liquid environments as well as with each other. Such interactions have been quantified and visualized as the processes occur. Potentials of mean force have been computed as functions of the separation distances in order to obtain the binding affinities. The atomistic details of how a nanoparticle interacts with its aqueous environments and with another nanoparticle have been understood for various ligands and aqueous solutions.

  19. Interaction of norfloxacin with bovine serum albumin studied by different spectrometric methods; displacement studies, molecular modeling and chemometrics approaches

    Energy Technology Data Exchange (ETDEWEB)

    Naseri, Abdolhossein, E-mail: a_naseri@tabrizu.ac.ir [Departments of Analytical Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz 51666-16471 (Iran, Islamic Republic of); Hosseini, Soheila [Departments of Analytical Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz 51666-16471 (Iran, Islamic Republic of); Rasoulzadeh, Farzaneh [Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz 51644-14766 (Iran, Islamic Republic of); Rashidi, Mohammad-Reza [Research Center for Pharmaceutical Nanotechnology, Tabriz University of Medical Sciences, Tabriz 51644-14766 (Iran, Islamic Republic of); Zakery, Maryam; Khayamian, Taghi [Department of Chemistry, College of Chemistry, Isfahan University of Technology, Isfahan 84154 (Iran, Islamic Republic of)

    2015-01-15

    Serum albumins as major target proteins can bind to other ligands leading to alteration of their pharmacological properties. The mechanism of interaction between norfloxacin (NFLX) with bovine serum albumin (BSA) was investigated. Fuorescence quenching of serum albumin by this drug was found to be a static quenching process. The binding sites number, n, apparent binding constant, K, and thermodynamic parameters were calculated at different temperatures. The distance, r, between donor, BSA, and acceptor, NFLX, was calculated according to the Forster theory of non-radiation energy transfer. Also binding characteristics of NFLX with BSA together with its displacement from its binding site by kanamycin and effect of common metal ions on binding constant were investigated by the spectroscopic methods. The conformational change in the secondary structure of BSA upon interaction with NFLX was investigated qualitatively from synchronous fluorescence spectra, Fourier Transform Infrared (FTIR) and circular dichroism (CD) spectrometric methods. Molecular docking studies were performed to obtain information on the possible residues involved in the interaction process and changes in accessible surface area of the interacting residues. The results showed that the conformation of BSA changed in the presence of NFLX. For the first time, displacement studies were used for this interaction; displacement studies showed that NFLX was displaced by phenylbutazon and ketoprofen but was not displaced by ibuprofen indicating that the binding site of NFLX on albumin was site I. In addition a powerful chemometrics method, multivariate curve resolution-alternating least square, was used for resolution of spectroscopic augmented data obtained in two different titration modes in order to extract spectral information regardless of spectral overlapping of components. - Highlights: • Interaction between norfloxacin and BSA is studied by spectral methods. • Chemometrics methods are used to

  20. Theoretical Chemistry Study of the Hydrogen-bonded Interaction between Acylamine and Chloromethane Compounds

    Institute of Scientific and Technical Information of China (English)

    GE Qing-Yu; WANG Hai-Jun; CHEN Jian-Hua

    2005-01-01

    The hydrogen-bonded interaction between acylamine and chloromethane was studied using theoretical calculation methods. Looking the interaction system as a hydrogen-bonded complex, the geometric optimization of the interaction system was performed with HF and B3LYP methods at 6-311++G** level. Stable structures of these complexes were obtained. Binding energies and some other physical chemistry parameters of them were computed and compared. According to the calculation results, it can be identified that DMA (DMF or DEF) can form stable complex with chloromethane by the hydrogen-bonded interaction between them. The stable orders of these hydrogen-bonded complexes were obtained and described as: DMF-CHCl3>DMF-CH2Cl2>DMF-CH3Cl, DEF-CHCl3>DEF-CH2Cl2>DEF-CH3Cl, DMA-CHCl3>DMA-CH2Cl2>DMA-CH3Cl, respectively.