Science.gov

Sample records for conformal groups

  1. Conformal Carroll groups

    NASA Astrophysics Data System (ADS)

    Duval, C.; Gibbons, G. W.; Horvathy, P. A.

    2014-08-01

    Conformal extensions of Lévy-Leblond's Carroll group, based on geometric properties analogous to those of Newton-Cartan space-time are proposed. The extensions are labeled by an integer k. This framework includes and extends our recent study of the Bondi-Metzner-Sachs (BMS) and Newman-Unti (NU) groups. The relation to conformal Galilei groups is clarified. Conformal Carroll symmetry is illustrated by ‘Carrollian photons’. Motion both in the Newton-Cartan and Carroll spaces may be related to that of strings in the Bargmann space.

  2. Group Cohesiveness, Deviation, Stress, and Conformity

    DTIC Science & Technology

    1993-08-11

    assessed pre- and post- conformity pressure (see Appendix VIII). Components of group influences , Offer of Reward for Conformity (ORC), and Threat of...Cohesiveness Pressures to Uniformity Studies . . . . Evidence Supporting a Group Cohesiveness- Conformity Relationship . . . . . . Evidence Supporting a...Response and Conformity Pressure . . . . Stress and ORC and TPN . . . . . . . . TPN and Space Crews . . . . . . . . . . Summary of Group

  3. Conformal field theory on affine Lie groups

    SciTech Connect

    Clubok, Kenneth Sherman

    1996-04-01

    Working directly on affine Lie groups, we construct several new formulations of the WZW model, the gauged WZW model, and the generic affine-Virasoro action. In one formulation each of these conformal field theories (CFTs) is expressed as a one-dimensional mechanical system whose variables are coordinates on the affine Lie group. When written in terms of the affine group element, this formulation exhibits a two-dimensional WZW term. In another formulation each CFT is written as a two-dimensional field theory, with a three- dimensional WZW term, whose fields are coordinates on the affine group. On the basis of these equivalent formulations, we develop a translation dictionary in which the new formulations on the affine Lie group are understood as mode formulations of the conventional formulations on the Lie group. Using this dictionary, we also express each CFT as a three-dimensional field theory on the Lie group with a four-dimensional WZW term. 36 refs.

  4. Peer influence: neural mechanisms underlying in-group conformity.

    PubMed

    Stallen, Mirre; Smidts, Ale; Sanfey, Alan G

    2013-01-01

    People often conform to the behavior of others with whom they identify. However, it is unclear what fundamental mechanisms underlie this type of conformity. Here, we investigate the processes mediating in-group conformity by using functional magnetic resonance imaging (fMRI). Participants completed a perceptual decision-making task while undergoing fMRI, during which they were exposed to the judgments of both in-group and out-group members. Our data suggest that conformity to the in-group is mediated by both positive affect as well as the cognitive capacity of perspective taking. Examining the processes that drive in-group conformity by utilizing a basic decision-making paradigm combined with neuroimaging methods provides important insights into the potential mechanisms of conformity. These results may provide an integral step in developing more effective campaigns using group conformity as a tool for behavioral change.

  5. On being loud and proud: non-conformity and counter-conformity to group norms.

    PubMed

    Hornsey, Matthew J; Majkut, Louise; Terry, Deborah J; McKimmie, Blake M

    2003-09-01

    Most experiments on conformity have been conducted in relation to judgments of physical reality; surprisingly few papers have experimentally examined the influence of group norms on social issues with a moral component. In response to this, participants were told that they were either in a minority or in a majority relative to their university group in terms of their attitudes toward recognition of gay couples in law (Expt 1: N = 205) and a government apology to Aborigines (Expt 2: N = 110). In both experiments, it was found that participants who had a weak moral basis for their attitude conformed to the group norm on private behaviours. In contrast, those who had a strong moral basis for their attitude showed non-conformity on private behaviours and counter-conformity on public behaviours. Incidences of non-conformity and counter-conformity are discussed with reference to theory and research on normative influence.

  6. Conformally flat Lorentzian manifolds with special holonomy groups

    SciTech Connect

    Galaev, A S

    2013-09-30

    We obtain a local classification of conformally flat Lorentzian manifolds with special holonomy groups. The corresponding local metrics are certain extensions of Riemannian spaces of constant sectional curvature to Walker metrics. Bibliography: 28 titles.

  7. Broken current anomalous dimensions, conformal manifolds, and renormalization group flows

    NASA Astrophysics Data System (ADS)

    Bashmakov, Vladimir; Bertolini, Matteo; Raj, Himanshu

    2017-03-01

    We consider deformations of a conformal field theory that explicitly break some global symmetries of the theory. If the deformed theory is still a conformal field theory, one can exploit the constraints put by conformal symmetry to compute broken currents anomalous dimensions. We consider several instances of this scenario, using field theory techniques and also holographic ones, where necessary. Field theoretical methods suffice to discuss examples of symmetry-breaking deformations of the O (N ) model in d =4 -ɛ dimensions. Holography is instrumental, instead, for computing current anomalous dimensions in β -deformed superconformal field theories and in a class of supersymmetric renormalization group flows at large N .

  8. Invariant Differential Operators for Non-Compact Lie Groups: Euclidean Jordan Groups or Conformal Lie Groups

    NASA Astrophysics Data System (ADS)

    Dobrev, V. K.

    2013-01-01

    In the present paper we continue the project of systematic construction of invariant differential operators for non-compact semisimple Lie groups. Our starting points is the class of algebras, which we call 'conformal Lie algebras' (CLA), which have very similar properties to the conformal algebras of Minkowski space-time, though our aim is to go beyond this class in a natural way. For this we introduce the new notion of parabolic relation between two non-compact semisimple Lie algebras Script G and Script G' that have the same complexification and possess maximal parabolic subalgebras with the same complexification.

  9. Group theory and biomolecular conformation: I. Mathematical and computational models

    PubMed Central

    Chirikjian, Gregory S

    2010-01-01

    Biological macromolecules, and the complexes that they form, can be described in a variety of ways ranging from quantum mechanical and atomic chemical models, to coarser grained models of secondary structure and domains, to continuum models. At each of these levels, group theory can be used to describe both geometric symmetries and conformational motion. In this survey, a detailed account is provided of how group theory has been applied across computational structural biology to analyze the conformational shape and motion of macromolecules and complexes. PMID:20827378

  10. Oxytocin enhances implicit social conformity to both in-group and out-group opinions.

    PubMed

    Huang, Yi; Kendrick, Keith M; Zheng, Huimin; Yu, Rongjun

    2015-10-01

    People often alter their own preferences when facing conflicting opinions expressed by others. This is known as the social conformity effect and tends to be stronger in response to opinions expressed by in-group relative to out-group members. The hypothalamic neuropeptide oxytocin promotes in-group favoritism, elicits parochial altruism, and stimulates in-group conformity under explicit social pressure. In a double-blind, placebo-controlled design experiment using a facial attractiveness judgment task, we therefore investigated whether social conformity to either in-group or out-group opinions is influenced by intranasal oxytocin treatment when social pressure is implicit. After oxytocin or placebo treatment, male participants were asked to rate the attractiveness of unfamiliar Chinese female faces, and then they were informed of ratings given by peers from an in-group (Chinese) and out-group (Japanese) simultaneously. They were subsequently asked unexpectedly to re-rate the same faces. Results showed that oxytocin increased conformity to both in- and out-group opinions. Thus oxytocin promotes conformity to opinions of both in- and out-group members when social pressure is implicit, suggesting that it facilitates 'tend and befriend' behaviors by increasing the general level of social conformity.

  11. Flat connection, conformal field theory and quantum group

    SciTech Connect

    Kato, Mitsuhiro.

    1989-07-01

    General framework of linear first order differential equation for four-point conformal block is studied by using flat connection. Integrability and SL{sub 2} invariance restrict possible form of flat connection. Under a special ansatz classical Yang-Baxter equation appears as an integrability condition and the WZW model turns to be unique conformal field theory in that case. Monodromy property of conformal block can be easily determined by the flat connection. 11 refs.

  12. Effects of Achievement Motivation, Social Identity, and Peer Group Norms on Academic Conformity

    ERIC Educational Resources Information Center

    Masland, Lindsay C.; Lease, A. Michele

    2013-01-01

    This study investigated whether academic achievement motivation and social identity explain variation in children's conformity to positive academic behaviors (n = 455 children in grades three through five). Structural equation modeling suggested that academic value and peer group academic norms were positively related to academic conformity.…

  13. EFFECT OF FUNCTIONAL GROUP CONFORMATION ON THE INFRARED SPECTRA OF SOME GEM DIFUNCTIONAL PHENYLETHYLENE DERIVATIVES,

    DTIC Science & Technology

    each functional group . The two bands for similar functional groups have been ascribed to S-cis- and S-trans- conformations of the carbonyl groups with...Except for the benzalmalononitriles, two functional group stretching vibrations occur in the infrared (i.r.) spectra of the beta,beta-difunctional...styrenes with similar functional groups . For geometrically homogeneous compounds with dissimilar functional groups only one absorption band occurs for

  14. Isotope-Encoded Carboxyl Group Footprinting for Mass Spectrometry-Based Protein Conformational Studies

    NASA Astrophysics Data System (ADS)

    Zhang, Hao; Liu, Haijun; Blankenship, Robert E.; Gross, Michael L.

    2016-01-01

    We report an isotope-encoding method coupled with carboxyl-group footprinting to monitor protein conformational changes. The carboxyl groups of aspartic/glutamic acids and of the C-terminus of proteins can serve as reporters for protein conformational changes when labeled with glycine ethyl ester (GEE) mediated by carbodiimide. In the new development, isotope-encoded "heavy" and "light" GEE are used to label separately the two states of the orange carotenoid protein (OCP) from cyanobacteria. Two samples are mixed (1:1 ratio) and analyzed by a single LC-MS/MS experiment. The differences in labeling extent between the two states are represented by the ratio of the "heavy" and "light" peptides, providing information about protein conformational changes. Combining isotope-encoded MS quantitative analysis and carboxyl-group footprinting reduces the time of MS analysis and improves the sensitivity of GEE and other footprinting.

  15. TOPICAL REVIEW: Group theory and biomolecular conformation: I. Mathematical and computational models

    NASA Astrophysics Data System (ADS)

    Chirikjian, Gregory S.

    2010-08-01

    Biological macromolecules, and the complexes that they form, can be described in a variety of ways ranging from quantum mechanical and atomic chemical models, to coarser grained models of secondary structure and domains, to continuum models. At each of these levels, group theory can be used to describe both geometric symmetries and conformational motion. In this survey, a detailed account is provided of how group theory has been applied across computational structural biology to analyze the conformational shape and motion of macromolecules and complexes.

  16. Alone against the group: A unanimously disagreeing group leads to conformity, but cardiovascular threat depends on one's goals.

    PubMed

    Seery, Mark D; Gabriel, Shira; Lupien, Shannon P; Shimizu, Mitsuru

    2016-08-01

    A long history of research in psychology has studied the consequences of when individuals face a group that unanimously disagrees with them. However, relatively little research has attempted to understand individuals' internal reactions to such disagreement while it is experienced. Psychophysiological measures are particularly well suited for this purpose. We used the perspective of the biopsychosocial model of challenge/threat to test whether and under what circumstances expressing one's political opinion to a disagreeing group led to a cardiovascular threat response (high total peripheral resistance, low cardiac output). We hypothesized that, when participants were provided with a goal to fit in with the group, a disagreeing group would elicit cardiovascular responses consistent with greater threat than an agreeing group, but that this effect would disappear if not reverse when participants were provided with a goal to express their individuality. Results supported hypotheses and further revealed a divergence between cardiovascular responses and conformity behavior, such that a disagreeing group fostered conformity regardless of goal condition. These findings suggest that (a) facing the prospect of a disagreeing group need not necessarily result in the negative experience of threat (reflecting evaluating low resources/high demands), and (b) conformity behavior can mask a range of internal states.

  17. Conformational influence of the ribose 2'-hydroxyl group: crystal structures of DNA-RNA chimeric duplexes

    NASA Technical Reports Server (NTRS)

    Egli, M.; Usman, N.; Rich, A.

    1993-01-01

    We have crystallized three double-helical DNA-RNA chimeric duplexes and determined their structures by X-ray crystallography at resolutions between 2 and 2.25 A. The two self-complementary duplexes [r(G)d(CGTATACGC)]2 and [d(GCGT)r(A)d(TACGC)]2, as well as the Okazaki fragment d(GGGTATACGC).r(GCG)d(TATACCC), were found to adopt A-type conformations. The crystal structures are non-isomorphous, and the crystallographic environments for the three chimeras are different. A number of intramolecular interactions of the ribose 2'-hydroxyl groups contribute to the stabilization of the A-conformation. Hydrogen bonds between 2'-hydroxyls and 5'-oxygens or phosphate oxygens, in addition to the previously observed hydrogen bonds to 1'-oxygens of adjacent riboses and deoxyriboses, are observed in the DNA-RNA chimeric duplexes. The crystalline chimeric duplexes do not show a transition between the DNA A- and B-conformations. CD spectra suggest that the Okazaki fragment assumes an A-conformation in solution as well. In this molecule the three RNA residues may therefore lock the complete decamer in the A-conformation. Crystals of an all-DNA strand with the same sequence as the self-complementary chimeras show a morphology which is different from those of the chimera crystals. Moreover, the oligonucleotide does not match any of the sequence characteristics of DNAs usually adopting the A-conformation in the crystalline state (e.g., octamers with short alternating stretches of purines and pyrimidines). In DNA-RNA chimeric duplexes, it is therefore possible that a single RNA residue can drive the conformational equilibrium toward the A-conformation.

  18. Conformational Properties of Helical Protein Polymers with Varying Densities of Chemically Reactive Groups.

    PubMed

    Farmer, Robin S; Argust, Lindsey M; Sharp, Jared D; Kiick, Kristi L

    2006-01-01

    Protein engineering strategies have proven valuable for the production of a variety of well-defined macromolecular materials with controlled properties that have enabled their use in a range of materials and biological applications. In this work, such biosynthetic strategies have been employed in the production of monodisperse alanine-rich, helical protein polymers with the sequences [AAAQEAAAAQAAAQAEAAQAAQ](3) and [AAAQAAQAQAAAEAAAQAAQAQ](6). The composition of these protein polymers is similar to that of a previously reported family of alanine-rich protein polymers, but the density and placement of chemically reactive residues has been varied to facilitate the future use of these macromolecules in elucidating polymeric structure-function relationships in biological recognition events. Both protein polymers are readily expressed from E. coli and purified to homogeneity; characterization of their conformational behavior via circular dichroic spectroscopy (CD) indicates that they adopt highly helical conformations under a range of solution conditions. Differential scanning calorimetry, in concert with CD, demonstrates that the conformational transition from helix to coil in these macromolecules can be well-defined, with helicity, conformational transitions, T(m) values, and calorimetric enthalpies that vary with the molecular weight of the protein polymers. A combination of infrared spectroscopy and CD also reveals that the macromolecules can adopt beta-sheet structures at elevated temperatures and concentrations and that the existence and kinetics of this conformational transition appear to be related to the density of charged groups on the protein polymer.

  19. On the social influence of emotions in groups: interpersonal effects of anger and happiness on conformity versus deviance.

    PubMed

    Heerdink, Marc W; van Kleef, Gerben A; Homan, Astrid C; Fischer, Agneta H

    2013-08-01

    How do emotional expressions of group members shape conformity versus deviance in groups? We hypothesized that angry and happy responses to a group member's deviating opinion are interpreted as signals of imminent rejection versus acceptance. In 5 studies, the majority's expressions of anger led the deviant individual to feel rejected, whereas expressions of happiness made the deviant feel accepted. Because conformity can be seen as strategic behavior aimed at gaining (re)acceptance, the effects of emotional expressions on conformity should be moderated by social-contextual factors that determine the motivation to be accepted by the group and by the extent to which conformity is a means to this end. Accordingly, in Study 2, the availability of alternative groups determined whether a deviant conformed to the current group or abandoned the group after an angry reaction. In Study 3, anger and happiness were only associated with conformity pressure in situations that were perceived as cooperative (rather than competitive). Employing an interactive group task in Study 4, we showed that individuals who received an angry reaction contributed less in a cooperative group task than did those who received a neutral or happy reaction. Finally, in Study 5, peripheral group members conformed more after an angry reaction than after a happy reaction, but prototypical group members did not. Moreover, conformity was still manifest 3 weeks after the experiment, and this effect was mediated by feelings of rejection. We discuss implications of these findings for theorizing about social functions of emotions and the role of emotions in groups.

  20. EEG reveals an early influence of social conformity on visual processing in group pressure situations.

    PubMed

    Trautmann-Lengsfeld, Sina Alexa; Herrmann, Christoph Siegfried

    2013-01-01

    Humans are social beings and often have to perceive and perform within groups. In conflict situations, this puts them under pressure to either adhere to the group opinion or to risk controversy with the group. Psychological experiments have demonstrated that study participants adapt to erroneous group opinions in visual perception tasks, which they can easily solve correctly when performing on their own. Until this point, however, it is unclear whether this phenomenon of social conformity influences early stages of perception that might not even reach awareness or later stages of conscious decision-making. Using electroencephalography, this study has revealed that social conformity to the wrong group opinion resulted in a decrease of the posterior-lateral P1 in line with a decrease of the later centro-parietal P3. These results suggest that group pressure situations impact early unconscious visual perceptual processing, which results in a later diminished stimulus discrimination and an adaptation even to the wrong group opinion. These findings might have important implications for understanding social behavior in group settings and are discussed within the framework of social influence on eyewitness testimony.

  1. Spectral analysis on the group of conformal automorphisms of the unit disc

    NASA Astrophysics Data System (ADS)

    Volchkov, V. V.; Volchkov, V. V.

    2016-07-01

    For the group G of conformal automorphisms of the unit disc the problem of spectral analysis is considered for subspaces \\mathscr{U}\\subset C(G) which are invariant under right shifts by elements of G and conjugations by elements of the rotation subgroup. It turns out that, in contrast to subspaces of C(G) which are merely invariant under right shifts, \\mathscr{U} contains a minimal subspace with the above properties. Bibliography: 26 titles.

  2. Conformation study of helical main-group polymers: Organic and inorganic, trans and gauche

    SciTech Connect

    Cui, C.X.; Kertesz, M. )

    1989-06-07

    In this paper electronic structures of some helical polymers, which range from typical organic polymers such as polyethylene and poly(oxymethylene) to standard inorganic polymers such as polymeric sulfur to main-group (P, B, etc.) atomic chains in crystals (such as NaP, CrB, etc.), have been investigated by means of our helical modifications of solid-state band theory programs based on modified neglect of diatomic overlap (MNDO) and extended Hueckel theory (EHT). The analysis of orbital interactions shows that the all-trans conformation for the polymer with either less or more than six valence electrons in the repeat unit is energetically favorable as compared with the gauche conformation while the polymers having valence electrons close to six in the repeat unit are more likely to be found in a gauche conformation, except for polyethylene and polysilane, for which both conformations are stable. The stability of all-trans-polyethylene and -polysilane is attributed to the weak repulsions between C-H and Si-H bonding electron pairs. A quadratic relationship between band width and the corresponding closed-shell repulsion for an energy band is established.

  3. a Natural Extension of the Conformal Lorentz Group in a Field Theory Context

    NASA Astrophysics Data System (ADS)

    László, András

    In this paper a finite dimensional unital associative algebra is presented, and its group of algebra automorphisms is detailed. The studied algebra can physically be understood as the creation operator algebra in a formal quantum field theory at fixed momentum for a spin 1/2 particle along with its antiparticle. It is shown that the essential part of the corresponding automorphism group can naturally be related to the conformal Lorentz group. In addition, the nonsemisimple part of the automorphism group can be understood as "dressing" of the pure one-particle states. The studied mathematical structure may help in constructing quantum field theories in a non-perturbative manner. In addition, it provides a simple example of circumventing Coleman-Mandula theorem using non-semisimple groups, without SUSY.

  4. Oxytocin Conditions Intergroup Relations Through Upregulated In-Group Empathy, Cooperation, Conformity, and Defense.

    PubMed

    De Dreu, Carsten K W; Kret, Mariska E

    2016-02-01

    Humans live in, rely on, and contribute to groups. Evolution may have biologically prepared them to quickly identify others as belonging to the in-group (vs. not), to decode emotional states, and to empathize with in-group members; to learn and conform to group norms and cultural practices; to extend and reciprocate trust and cooperation; and to aggressively protect the in-group against outside threat. We review evidence that these components of human group psychology rest on and are modulated by the hypothalamic neuropeptide oxytocin. It appears that oxytocin motivates and enables humans to 1) like and empathize with others in their groups, 2) comply with group norms and cultural practices, and 3) extend and reciprocate trust and cooperation, which may give rise to intergroup discrimination and sometimes defensive aggression against threatening (members of) out-groups. We explore the possibility that deficiencies in (components of) group psychology, seen in autistic spectrum disorder, schizophrenia, and borderline personality and social anxiety disorders, may be reduced by oxytocin administration. Avenues for new research are highlighted, and implications for the role of oxytocin in cooperation and competition within and between groups are discussed.

  5. Conformational responses to changes in the state of ionization of titrable groups in proteins

    NASA Astrophysics Data System (ADS)

    Richman, Daniel Eric

    Electrostatic energy links the structural properties of proteins with some of their important biological functions, including catalysis, energy transduction, and binding and recognition. Accurate calculation of electrostatic energy is essential for predicting and for analyzing function from structure. All proteins have many ionizable residues at the protein-water interface. These groups tend to have ionization equilibria (pK a values) shifted slightly relative to their values in water. In contrast, groups buried in the hydrophobic interior usually have highly anomalous p Ka values. These shifts are what structure-based calculations have to reproduce to allow examination of contributions from electrostatics to stability, solubility and interactions of proteins. Electrostatic energies are challenging to calculate accurately because proteins are heterogeneous dielectric materials. Any individual ionizable group can experience very different local environments with different dielectric properties. The studies in this thesis examine the hypothesis that proteins reorganize concomitant with changes in their state of ionization. It appears that the pKa value measured experimentally reflects the average of pKa values experienced in the different electrostatic environments corresponding to different conformational microstates. Current computational models fail to sample conformational reorganization of the backbone correctly. Staphyloccocal nuclease (SNase) was used as a model protein in nuclear magnetic resonance (NMR) spectroscopy studies to characterize the conformational rearrangements of the protein coupled to changes in the ionization state of titrable groups. One set of experiments tests the hypothesis that proton binding to surface Asp and Glu side chains drives local unfolding by stabilizing less-native, more water-solvated conformations in which the side chains have normalized pKa values. Increased backbone flexibility in the ps-ns timescale, hydrogen bond (H

  6. Fate of the conformal fixed point with twelve massless fermions and SU(3) gauge group

    NASA Astrophysics Data System (ADS)

    Fodor, Zoltan; Holland, Kieran; Kuti, Julius; Mondal, Santanu; Nogradi, Daniel; Wong, Chik Him

    2016-11-01

    We report new results on the conformal properties of an important strongly coupled gauge theory, a building block of composite Higgs models beyond the Standard Model. With twelve massless fermions in the fundamental representation of the SU(3) color gauge group, an infrared fixed point (IRFP) of the β -function was recently reported in the theory [A. Cheng, A. Hasenfratz, Y. Liu, G. Petropoulos, and D. Schaich, J. High Energy Phys. 05 (2014) 137] with uncertainty in the location of the critical gauge coupling inside the narrow [6.0 conformal fixed point and scale invariance in the theory with model-building implications. Using the exact same renormalization scheme as the previous study, we show that no fixed point of the β -function exists in the reported interval. Our findings eliminate the only seemingly credible evidence for conformal fixed point and scale invariance in the Nf=12 model whose infrared properties remain unresolved. The implications of the recently completed 5-loop QCD β -function for arbitrary flavor number are discussed with respect to our work.

  7. Conformal or walking? Monte Carlo renormalization group studies of SU(3) gauge models with fundamental fermions

    SciTech Connect

    Hasenfratz, Anna

    2010-07-01

    Strongly coupled gauge systems with many fermions are important in many phenomenological models. I use the 2-lattice matching Monte Carlo renormalization group method to study the fixed point structure and critical indexes of SU(3) gauge models with 8 and 12 flavors of fundamental fermions. With an improved renormalization group block transformation I am able to connect the perturbative and confining regimes of the N{sub f}=8 flavor system, thus verifying its QCD-like nature. With N{sub f}=12 flavors the data favor the existence of an infrared fixed point and conformal phase, though the results are also consistent with very slow walking. I measure the anomalous mass dimension in both systems at several gauge couplings and find that they are barely different from the free-field value.

  8. Emotional reactions to deviance in groups: the relation between number of angry reactions, felt rejection, and conformity

    PubMed Central

    Heerdink, Marc W.; van Kleef, Gerben A.; Homan, Astrid C.; Fischer, Agneta H.

    2015-01-01

    How many members of a group need to express their anger in order to influence a deviant group member’s behavior? In two studies, we examine whether an increase in number of angry group members affects the extent to which a deviant individual feels rejected, and we investigate downstream effects on conformity. We show that each additional angry reaction linearly increases the extent to which a deviant individual feels rejected, and that this relation is independent of the total number of majority members (Study 1). This felt rejection is then shown to lead to anti-conformity unless two conditions are met: (1) the deviant is motivated to seek reacceptance in the group, and (2) conformity is instrumental in gaining reacceptance because it is observable by the majority (Study 2). These findings show that angry reactions are likely to trigger anti-conformity in a deviant, but they are also consistent with a motivational account of conformity, in which conformity is strategic behavior aimed at gaining reacceptance from the group. PMID:26124742

  9. Emotional reactions to deviance in groups: the relation between number of angry reactions, felt rejection, and conformity.

    PubMed

    Heerdink, Marc W; van Kleef, Gerben A; Homan, Astrid C; Fischer, Agneta H

    2015-01-01

    How many members of a group need to express their anger in order to influence a deviant group member's behavior? In two studies, we examine whether an increase in number of angry group members affects the extent to which a deviant individual feels rejected, and we investigate downstream effects on conformity. We show that each additional angry reaction linearly increases the extent to which a deviant individual feels rejected, and that this relation is independent of the total number of majority members (Study 1). This felt rejection is then shown to lead to anti-conformity unless two conditions are met: (1) the deviant is motivated to seek reacceptance in the group, and (2) conformity is instrumental in gaining reacceptance because it is observable by the majority (Study 2). These findings show that angry reactions are likely to trigger anti-conformity in a deviant, but they are also consistent with a motivational account of conformity, in which conformity is strategic behavior aimed at gaining reacceptance from the group.

  10. QUENCHING OF STAR FORMATION IN SLOAN DIGITAL SKY SURVEY GROUPS: CENTRALS, SATELLITES, AND GALACTIC CONFORMITY

    SciTech Connect

    Knobel, Christian; Lilly, Simon J.; Woo, Joanna; Kovač, Katarina

    2015-02-10

    We re-examine the fraction of low-redshift Sloan Digital Sky Survey satellites and centrals in which star formation has been quenched, using the environment quenching efficiency formalism that separates out the dependence of stellar mass. We show that the centrals of the groups containing the satellites are responding to the environment in the same way as their satellites (at least for stellar masses above 10{sup 10.3} M {sub ☉}), and that the well-known differences between satellites and the general set of centrals arise because the latter are overwhelmingly dominated by isolated galaxies. The widespread concept of ''satellite quenching'' as the cause of environmental effects in the galaxy population can therefore be generalized to ''group quenching''. We then explore the dependence of the quenching efficiency of satellites on overdensity, group-centric distance, halo mass, the stellar mass of the satellite, and the stellar mass and specific star formation rate (sSFR) of its central, trying to isolate the effect of these often interdependent variables. We emphasize the importance of the central sSFR in the quenching efficiency of the associated satellites, and develop the meaning of this ''galactic conformity'' effect in a probabilistic description of the quenching of galaxies. We show that conformity is strong, and that it varies strongly across parameter space. Several arguments then suggest that environmental quenching and mass quenching may be different manifestations of the same underlying process. The marked difference in the apparent mass dependencies of environment quenching and mass quenching which produces distinctive signatures in the mass functions of centrals and satellites will arise naturally, since, for satellites at least, the distributions of the environmental variables that we investigate in this work are essentially independent of the stellar mass of the satellite.

  11. Conformal invariance and renormalization group in quantum gravity near two dimensions

    NASA Astrophysics Data System (ADS)

    Aida, Toshiaki; Kitazawa, Yoshihisa; Kawai, Hikaru; Ninomiya, Masao

    1994-09-01

    We study quantum gravity in 2 + ɛ dimensions in such a way as to preserve the volume-preserving diffeomorphism invariance. In such a formulation, we prove the following trinity: the general covariance, the conformal invariance and the renormalization group flow to the Einstein theory at long distance. We emphasize that the consistent and macroscopic universes like our own can only exist for a matter central charge 0 < c < 25. We show that the spacetime singularity at the big bang is resolved by the renormalization effect and universes are found to bounce back from the big crunch. Our formulation may be viewed as a Ginzburg-Landau theory which can describe both the broken and the unbroken phase of quantum gravity and the phase transition between them.

  12. NMR and molecular dynamics studies of the conformational epitope of the type III group B Streptococcus capsular polysaccharide and derivatives.

    PubMed

    Brisson, J R; Uhrinova, S; Woods, R J; van der Zwan, M; Jarrell, H C; Paoletti, L C; Kasper, D L; Jennings, H J

    1997-03-18

    The conformational epitope of the type III group B Streptococcus capsular polysaccharide (GBSP III) exhibits unique properties which can be ascribed to the presence of sialic acid in its structure and the requirement for an extended binding site. By means of NMR and molecular dynamics studies on GBSP III and its fragments, the extended epitope of GBSP III was further defined. The influence of sialic acid on the conformational properties of GBSP III was examined by performing conformational analysis on desialylated GBSP III, which is identical to the polysaccharide of Streptococcus pneumoniae type 14, and also on oxidized and reduced GBSP III. Conformational changes were gauged by 1H and 13C chemical shift analysis, NOE, 1D selective TOCSY-NOESY experiments, J(HH) and J(CH) variations, and NOE of OH resonances. Changes in mobility were examined by 13C T1 and T2 measurements. Unrestrained molecular dynamics simulations with explicit water using the AMBER force field and the GLYCAM parameter set were used to assess static and dynamic conformational models, simulate the observable NMR parameters and calculate helical parameters. GBSP III was found to be capable of forming extended helices. Hence, the length dependence of the conformational epitope could be explained by its location on extended helices within the random coil structure of GBSP III. The interaction of sialic acid with the backbone of the PS was also found to be important in defining the conformational epitope of GBSP III.

  13. Conformations and Barriers to Methyl Group Internal Rotation in Two Asymmetric Ethers: Propyl Methyl Ether and Butyl Methyl Ether

    NASA Astrophysics Data System (ADS)

    Long, B. E.; Dechirico, F.; Cooke, S. A.

    2012-06-01

    The conformational preferences of the O-C-C-C unit are important in many biological systems with the unit generally preferring a gauche configuration compared to an anti configuration. Butyl methyl ether and propyl methyl ether provide very simple systems for this phenomenom to manifest. Pure rotational spectra of the title molecules have been recorded using chirped pulse Fourier transform microwave spectroscopy (CP-FTMW). In the case of butyl methyl ether, only one conformer has been observed. This conformer has torsional angles of COCC = 180°, OCCC = 62° and CCCC = 180° (anti-gauche-anti) and rotational constants of A = 10259.4591(33) MHz, B = 1445.6470(13) MHz, and C = 1356.2944(14) MHz. The rotational spectrum was doubled and has been analyzed to produce an effective barrier to methyl group internal rotation of 780(35) cm-1. A prior rotational spectroscopic study on propyl methyl ether had focused only on the high energy anti-anti conformer. We have analyzed spectra from the lowest energy anti-gauche conformer and the spectroscopic constants will be presented. A summary of the differences in conformational energies and methyl group internal rotation barriers for the class of aliphatic asymmetric ethers will be presented. K. N. Houk, J. E. Eksterowicz, Y.-D. Wu, C. D. Fuglesang, D. B. Mitchell. J. Am. Chem. Soc. 115 (4170), 1993. Hiroshi Kato, Jun Nakagawa, Michiro Hayashi. J. Mol. Spectrosc. 80 (272), 1980.

  14. Effect of methyl groups on conformational properties of small ionized comb-like polyelectrolytes at the atomic level.

    PubMed

    Zhao, Hongxia; Liu, Jiaping; Ran, Qianping; Yang, Yong; Shu, Xin

    2017-03-01

    Comb-like polycarboxylate ether (PCE) molecules with different content of methyl groups substituted on backbone and different location of methyl groups substituted on the side chains, respectively, were designed and were studied in explicit salt solutions by all-atom molecular dynamics simulations. Methyl groups substituted on the backbone of PCE have a great effect on the conformation of PCE. Stiffness of charged backbone was not only affected by the rotational freedom but also the electrostatic repulsion between the charged COO(-) groups. The interaction of counterions (Na(+)) with COO(-) groups for PCE3 (with part of AA substituted by MAA on the backbone) was stronger and the screen effect was great, which decided the smaller size of PCE3. The interaction between water and COO(-) groups was strong regardless of the content of AA substituted by MAA on the backbone. The effect of methyl groups substituted on the different location of side chains on the conformation of PCE was less than that of methyl groups substituted on the backbone. The equilibrium sizes of the four PCE molecules with methyl groups substituted on the side chains were similar. Graphical Abstract Effect of methyl groups on conformational properties of small ionized comb-like polyelectrolytes at the atomic level.

  15. Conformation-dependent restraints for polynucleotides: I. Clustering of the geometry of the phosphodiester group

    PubMed Central

    Kowiel, Marcin; Brzezinski, Dariusz; Jaskolski, Mariusz

    2016-01-01

    The refinement of macromolecular structures is usually aided by prior stereochemical knowledge in the form of geometrical restraints. Such restraints are also used for the flexible sugar-phosphate backbones of nucleic acids. However, recent highly accurate structural studies of DNA suggest that the phosphate bond angles may have inadequate description in the existing stereochemical dictionaries. In this paper, we analyze the bonding deformations of the phosphodiester groups in the Cambridge Structural Database, cluster the studied fragments into six conformation-related categories and propose a revised set of restraints for the O-P-O bond angles and distances. The proposed restraints have been positively validated against data from the Nucleic Acid Database and an ultrahigh-resolution Z-DNA structure in the Protein Data Bank. Additionally, the manual classification of PO4 geometry is compared with geometrical clusters automatically discovered by machine learning methods. The machine learning cluster analysis provides useful insights and a practical example for general applications of clustering algorithms for automatic discovery of hidden patterns of molecular geometry. Finally, we describe the implementation and application of a public-domain web server for automatic generation of the proposed restraints. PMID:27521371

  16. Conformation of a group 2 late embryogenesis abundant protein from soybean. Evidence of poly (L-proline)-type II structure.

    PubMed

    Soulages, Jose L; Kim, Kangmin; Arrese, Estela L; Walters, Christina; Cushman, John C

    2003-03-01

    Late embryogenesis abundant (LEA) proteins are members of a large group of hydrophilic, glycine-rich proteins found in plants, algae, fungi, and bacteria known collectively as hydrophilins that are preferentially expressed in response to dehydration or hyperosmotic stress. Group 2 LEA (dehydrins or responsive to abscisic acid) proteins are postulated to stabilize macromolecules against damage by freezing, dehydration, ionic, or osmotic stress. However, the structural and physicochemical properties of group 2 LEA proteins that account for such functions remain unknown. We have analyzed the structural properties of a recombinant form of a soybean (Glycine max) group 2 LEA (rGmDHN1). Differential scanning calorimetry of purified rGmDHN1 demonstrated that the protein does not display a cooperative unfolding transition upon heating. Ultraviolet absorption and circular dichroism spectroscopy revealed that the protein is in a largely hydrated and unstructured conformation in solution. However, ultraviolet absorption and circular dichroism measurements collected at different temperatures showed that the protein exists in equilibrium between two extended conformational states: unordered and left-handed extended helical or poly (L-proline)-type II structures. It is estimated that 27% of the residues of rGmDHN1 adopt or poly (L-proline)-type II-like helical conformation at 12 degrees C. The content of extended helix gradually decreases to 15% as the temperature is increased to 80 degrees C. Studies of the conformation of the protein in solution in the presence of liposomes, trifluoroethanol, and sodium dodecyl sulfate indicated that rGmDHN1 has a very low intrinsic ability to adopt alpha-helical structure and to interact with phospholipid bilayers through amphipathic alpha-helices. The ability of the protein to remain in a highly extended conformation at low temperatures could constitute the basis of the functional role of GmDHN1 in the prevention of freezing, desiccation

  17. Do Descriptive Norms Solve Social Dilemmas? Conformity and Contributions in Collective Action Groups

    ERIC Educational Resources Information Center

    Irwin, Kyle; Simpson, Brent

    2013-01-01

    Collective action researchers have focused on injunctive norms that specify approved behavior as a panacea for collective action problems. We investigate whether descriptive norms (similar behavior) can also solve these problems. We argue that descriptive norms generate social identification, which then sustains conformity to expectations.…

  18. Comparative analysis of the conformations of symmetrically and asymmetrically deca- and undecasubstituted porphyrins bearing meso-alkyl or -aryl groups

    SciTech Connect

    Senge, M.O.; Medforth, C.J.; Forsyth, T.P.

    1997-03-12

    Conformational analysis of highly substituted porphyrins, has potential implications for modeling the behavior of macrocycles in tetrapyrrole-containing protein complexes and during catalytic reactions. In order to study the influence of different substituent patterns of the conformation of the porphyrin macrocycle, a series of metal free and nickel(II) decasubstituted porphyrins bearing aryl or ethyl groups at opposite meso positions and alkyl groups at the pyrrole positions have been synthesized and characterized by X-ray crystallography. Crystal structures of the free-base porphyrins with 5,15-diaryl substituents showed negligible out-of-plane distortion but a large amount of in-plane distortion along the 5,15-axis accompanied by large bond angle changes similar to those previously seen for related porphyrins with 5,15-dialkyl substituents. Nickel(II) complexes of the 5,15-diaryl-substituted porphyrins show planar or modestly nonplanar conformations, suggesting that these complexes are not intrinsically nonplanar, whereas a complex with 5,15-diethyl substituents has a very ruffled conformation similar to those observed for related complexes with other metals. The nickel(II) complexes are also elongated along the 5,15-axis in a qualitatively similar but less dramatic fashion than are the free-base porphyrins. Spectroscopic studies ({sup 1}H NMR, optical, and resonance Raman spectroscopy) suggest that conformations similar to those determined by X-ray crystallography are present in solution for the 5,15-disubstituted porphyrins containing both aryl and alkyl mesosubstituents were also investigated. Metal-free 5,15-dialkyl- and 5,15-diaryl-substituted porphyrins. Several asymmetric nickel(II) and metal-free deca- and undecasubstituted porphyrins containing both aryl and alkyl mesosubstituents were also investigated.

  19. Natural bond orbital analyses of persulfoxide stabilization by remote functional groups. The conformationally induced electrostatic stabilization sulfide photooxygenation mechanism.

    PubMed

    Clennan, Edward L; Hightower, Sean E

    2006-02-03

    The conformationally induced electrostatic stabilization (CIES) sulfide photooxygenation mechanism was computationally examined using an ab initio model and extended to the study of new donor atoms. The MP2/6-31G(d) geometries and a natural population analysis of natural lone-pair orbitals on the donor atoms support the mechanism and reveal that oxygen and nitrogen donor groups are more stabilizing than sulfur.

  20. (±)Alkyl 3-hydroxy-1-azabicyclo[2.2.2]octane-3-carboxylates: conformational preferences of the alkoxycarbonyl group

    NASA Astrophysics Data System (ADS)

    Arias-Pérez, M. S.; Cosme, A.; Gálvez, E.; Morreale, A.

    2003-07-01

    Molecular mechanics, ab initio (RHF) and density functional (DFT/B3LYP) methods are applied to investigate the conformational preferences of the methoxycarbonyl group of the (±)methyl 3-hydroxy-1-azabicyclo[2.2.2]octane-3-carboxylate. 1H and 13C chemical shifts are also calculated by the GIAO/DFT approach and compared with experimental values. Both theoretical and experimental data account for almost eclipsed conformations with different degrees of distortion from the ideal geometry. It is found that calculations at the B3LYP/6-311G(d,p) level are relatively more reliable to explain the behaviour of the alkoxycarbonyl moiety of 2-hydroxyesters derived from the (±)3-hydroxy-1-azabicyclo[2.2.2]octane-3-carboxylic acid.

  1. Raman spectra and molecular conformation of 2,4,4-trimethyl-2-pentanethiol as a model compound of a hydrophobic group of triton X-100 surfactant

    NASA Astrophysics Data System (ADS)

    Matsuura, Hiroatsu; Fukuhara, Koichi

    1986-05-01

    Raman spectra of 2,4,4-trimethyl-2-pentanethiol were measured. The spectral analysis with the normal coordinate treatment indicated that this molecule takes the gauche conformation about the CCCS bond in the solid state and the trans and gauche conformations in the liquid state. The Raman bands due to the totally symmetric C&.zdbnd;C streching vibration of the t-butyl part of the 1,1,3,3-tetramethylbutyl group were found to be important to distinguish the two conformations. These key bands were applied to the interpretation of the Raman spectra of Triton X-100 surfactant which contains the p-(1,1,3,3-tetramethylbutyl)phenoxyl group as a hydrophobic moiety. The 1,1,3,3-tetramethylbutyl group of Triton X-100 molecules is shown to be predominantly in the gauche conformation in the liquid state and in aquaeous solution.

  2. Steinberg conformal algebras

    NASA Astrophysics Data System (ADS)

    Mikhalev, A. V.; Pinchuk, I. A.

    2005-06-01

    The structure of Steinberg conformal algebras is studied; these are analogues of Steinberg groups (algebras, superalgebras).A Steinberg conformal algebra is defined as an abstract algebra by a system of generators and relations between the generators. It is proved that a Steinberg conformal algebra is the universal central extension of the corresponding conformal Lie algebra; the kernel of this extension is calculated.

  3. Conformational study of the binding of a high mobility group protein with chromatin

    SciTech Connect

    Sasi, R.; Huvoes, P.E.; Fasman, G.D.

    1982-10-10

    The nature of the binding of a high mobility group protein (HMG 17) to native and H1-H5-depleted chicken erythrocyte chromatin was studied, as a function of ionic strength, using circular dichroism and thermal denaturation techniques. The circular dichroism properties of the HMG 17-reconstituted whole chromatin and H1-H5-depleted chromatin structure occurred upon HMG 17 binding at low ionic strength. Thermal denaturation profiles confirmed this change in the structure of chromatin induced by HMG 17. Thermal denaturation profiles were resolved into three-component transitions. These results indicate that the binding sites of HMG 17 are situated in the linker regions immediately adjacent to the core. The nature of the interaction of HMG 17 at higher ionic strength with whole chromatin and H1-H5-depleted chromatin was found to be different. These observations suggest that HMG 17 does not loosen chromatin structure but produces an overall stabilization and condensation of structure. The implications of these results to the currently accepted models of transcriptionally active chromatin are discussed.

  4. The difluoromethylene (CF2) group in aliphatic chains: Synthesis and conformational preference of palmitic acids and nonadecane containing CF2 groups.

    PubMed

    Wang, Yi; Callejo, Ricardo; Slawin, Alexandra M Z; O'Hagan, David

    2014-01-06

    The syntheses of palmitic acids and a nonadecane are reported with CF2 groups located 1,3 or 1,4 to each other along the aliphatic chain. Specifically 8,8,10,10- and 8,8,11,11-tetrafluorohexadecanoic acids (6b and 6c) are prepared as well as the singly modified analogue 8,8-difluorohexadecanoic acid (6a). Also 8,8,11,11-tetrafluorononadecane (27) is prepared as a pure hydrocarbon containing a 1,4-di-CF2 motif. The modified palmitic acids are characterized by differential scanning calorimetry (DSC) to determine melting points and phase behaviour relative to palmitic acid (62.5 °C). It emerges that 6c, with the CF2 groups placed 1,4- to each other, has a significantly higher melting point (89.9 °C) when compared to the other analogues and palmitic acid itself. It is a crystalline compound and the structure reveals an extended anti-zig-zag chain. Similarly 8,8,11,11-tetrafluorononadecane (27) adopts an extended anti-zig-zag structure. This is rationalized by dipolar relaxation between the two CF2 groups placed 1,4 to each other in the extended anti-zig-zag chain and suggests a design modification for long chain aliphatics which can introduce conformational stability.

  5. Origin of the conformational modulation of the 13C NMR chemical shift of methoxy groups in aromatic natural compounds.

    PubMed

    Toušek, Jaromír; Straka, Michal; Sklenář, Vladimír; Marek, Radek

    2013-01-24

    The interpretation of nuclear magnetic resonance (NMR) parameters is essential to understanding experimental observations at the molecular and supramolecular levels and to designing new and more efficient molecular probes. In many aromatic natural compounds, unusual (13)C NMR chemical shifts have been reported for out-of-plane methoxy groups bonded to the aromatic ring (~62 ppm as compared to the typical value of ~56 ppm for an aromatic methoxy group). Here, we analyzed this phenomenon for a series of aromatic natural compounds using Density Functional Theory (DFT) calculations. First, we checked the methodology used to optimize the structure and calculate the NMR chemical shifts in aromatic compounds. The conformational effects of the methoxy group on the (13)C NMR chemical shift then were interpreted by the Natural Bond Orbital (NBO) and Natural Chemical Shift (NCS) approaches, and by excitation analysis of the chemical shifts, breaking down the total nuclear shielding tensor into the contributions from the different occupied orbitals and their magnetic interactions with virtual orbitals. We discovered that the atypical (13)C NMR chemical shifts observed are not directly related to a different conjugation of the lone pair of electrons of the methoxy oxygen with the aromatic ring, as has been suggested. Our analysis indicates that rotation of the methoxy group induces changes in the virtual molecular orbital space, which, in turn, correlate with the predominant part of the contribution of the paramagnetic deshielding connected with the magnetic interactions of the BD(CMet-H)→BD*(CMet-OMet) orbitals, resulting in the experimentally observed deshielding of the (13)C NMR resonance of the out-of-plane methoxy group.

  6. Joined X-ray, spectroscopic and theoretical study of potential antibacterial cyano group containing fluoroquinolone drugs precursors with the focus on the conformational behavior

    NASA Astrophysics Data System (ADS)

    Dorotíková, Sandra; Kucková, Lenka; Malček, Michal; Plevová, Kristína; Kožíšek, Jozef; Milata, Viktor; Dvoranová, Dana; Bučinský, Lukáš

    2016-12-01

    Conformational behavior of 3-fluorophenylaminoethylene precursors of potential antibacterial fluoroquinolone drugs are investigated by the comparison of obtained experimental X-ray structures, IR vibrational frequencies and UV-vis transitions with B3LYP/6-311++G** theoretical calculations. Theoretical investigations of the conformational behavior are extended for the rotational energy barriers between ZZa-EZa and ZZa-ZEa conformers which are investigated along with the change of bond critical points characteristics and delocalization indices of quantum theory of atoms in molecules (including atomic and formal functional group charges). Subsequently, molecular dynamics simulations are presenting a critical assessment of the dynamics of distinguished dihedral angles which are related to the conformational behavior.

  7. Mean Deviation of Inter-rater Scoring (MDIS): a simple tool for introducing conformity into groups of clinical investigators.

    PubMed

    Bourin, Michel; Deplanque, Dominique; Zins-Ritter, Marcel

    2004-07-01

    In spite of considerable progress over the past decade, training investigators for inter-rater reliability for clinical trials remains a major problem. The aim of the present study was to promote a new tool to increase data homogeneity by introducing conformity into groups of clinical investigators. The investigators scoring grid we are proposing-the Mean Deviation of Inter-rater Scoring (MDIS)-involves the calculation of the score deviation for each investigator relative to the median score of an expert group who had evaluated the same videotape-recorded clinical case. Whatever the scale, the score deviation is calculated as the absolute deviation value from the median score obtained by the experts for each item. The MDIS value is then evaluated from all the scores given by an investigator by dividing the total sum of the previously defined values by the number of items of the scale. Some examples from practice are given using several rating scales: (i) Hamilton Anxiety Rating Scale; (ii) Hamilton Depression Rating Scale; (iii) Montgomery Asberg Depression Rating Scale; and (iv) Positive And Negative Symptoms Scale. Finally, such a method could also be employed by experts to evaluate the quality of videotape-recorded clinical cases used in clinical trials, as well as by teachers to evaluate initial or continuous medical training.

  8. Structural difference between group I and group II cobra cardiotoxins: X-ray, NMR, and CD analysis of the effect of cis-proline conformation on three-fingered toxins.

    PubMed

    Chen, Ting-Shou; Chung, Fong-Yu; Tjong, Siu-Cin; Goh, King-Siang; Huang, Wei-Ning; Chien, Kun-Yi; Wu, Po-Long; Lin, Hua-Ching; Chen, Chun-Jung; Wu, Wen-Guey

    2005-05-24

    Natural homologues of cobra cardiotoxins (CTXs) were classified into two structural subclasses of group I and II based on the amino acid sequence and circular dichroism analysis, but the exact differences in their three-dimensional structures and biological significance remain elusive. We show by circular dichroism, NMR spectroscopic, and X-ray crystallographic analyses of a newly purified group I CTX A6 from eastern Taiwan cobra (Naja atra) venoms that its loop I conformation adopts a type VIa turn with a cis peptide bond located between two proline residues of PPxY. A similar "banana-twisted" conformation can be observed in other group I CTXs and also in cyclolinopeptide A and its analogues. By binding to the membrane environment, group I CTX undergoes a conformational change to adopt a more extended hydrophobic domain with beta-sheet twisting closer to the one adopted by group II CTX. This result resolves a discrepancy in the CTX structural difference reported previously between solution as well as crystal state and shows that, in addition to the hydrophobicity, the exact loop I conformation also plays an important role in CTX-membrane interaction. Potential protein targets of group I CTXs after cell internalization are also discussed on the basis of the determined loop I conformation.

  9. Indirect readout of DNA sequence by p22 repressor: roles of DNA and protein functional groups in modulating DNA conformation.

    PubMed

    Harris, Lydia-Ann; Watkins, Derrick; Williams, Loren Dean; Koudelka, Gerald B

    2013-01-09

    The repressor of bacteriophage P22 (P22R) discriminates between its various DNA binding sites by sensing the identity of non-contacted base pairs at the center of its binding site. The "indirect readout" of these non-contacted bases is apparently based on DNA's sequence-dependent conformational preferences. The structures of P22R-DNA complexes indicate that the non-contacted base pairs at the center of the binding site are in the B' state. This finding suggests that indirect readout and therefore binding site discrimination depend on P22R's ability to either sense and/or impose the B' state on the non-contacted bases of its binding sites. We show here that the affinity of binding sites for P22R depends on the tendency of the central bases to assume the B'-DNA state. Furthermore, we identify functional groups in the minor groove of the non-contacted bases as the essential modulators of indirect readout by P22R. In P22R-DNA complexes, the negatively charged E44 and E48 residues are provocatively positioned near the negatively charged DNA phosphates of the non-contacted nucleotides. The close proximity of the negatively charged groups on protein and DNA suggests that electrostatics may play a key role in the indirect readout process. Changing either of two negatively charged residues to uncharged residues eliminates the ability of P22R to impose structural changes on DNA and to recognize non-contacted base sequence. These findings suggest that these negatively charged amino acids function to force the P22R-bound DNA into the B' state and therefore play a key role in indirect readout by P22R.

  10. Survey of Stereotactic Body Radiation Therapy in Japan by the Japan 3-D Conformal External Beam Radiotherapy Group

    SciTech Connect

    Nagata, Yasushi Hiraoka, Masahiro; Mizowaki, Takashi; Narita, Yuichiro; Matsuo, Yukinori; Norihisa, Yoshiki; Onishi, Hiroshi; Shirato, Hiroki

    2009-10-01

    Purpose: To recognize the current status of stereotactic body radiotherapy (SBRT) in Japan, using a nationwide survey conducted by the Japan 3-D Conformal External Beam Radiotherapy Group. Methods and Materials: The questionnaire was sent by mail to 117 institutions. Ninety-four institutions (80%) responded by the end of November 2005. Fifty-three institutions indicated that they have already started SBRT, and 38 institutions had been reimbursed by insurance. Results: A total of 1111 patients with histologically confirmed lung cancer were treated. Among these patients, 637 had T1N0M0 and 272 had T2N0M0 lung cancer. Metastatic lung cancer was found in 702 and histologically unconfirmed lung tumor in 291 patients. Primary liver cancer was found in 207 and metastatic liver cancer in 76 patients. The most frequent schedule used for primary lung cancer was 48Gy in 4 fractions at 22 institutions (52%), followed by 50Gy in 5 fractions at 11 institutions (26%) and 60Gy in 8 fractions at 4 institutions (10%). The tendency was the same for metastatic lung cancer. The average number of personnel involved in SBRT was 1.8 radiation oncologists, including 1.1 certified radiation oncologists, 2.8 technologists, 0.7 nurses, and 0.6 certified quality assurance personnel and 0.3 physicists. The most frequent amount of time for treatment planning was 61-120min, for quality assurance was 50-60min, and for treatment was 30min. There were 14 (0.6% of all cases) reported Grade 5 complications: 11 cases of radiation pneumonitis, 2 cases of hemoptysis, and 1 case of radiation esophagitis. Conclusion: The current status of SBRT in Japan was surveyed.

  11. Does the Age and Familiarity of the Informant Group Influence the Tendency of 3- and 4-year-old Children to Conform?

    PubMed

    McGuigan, Nicola; Stevenson, Amy

    2016-01-01

    The authors' aim was to explore whether the age and the familiarity of the individuals comprising a group majority influenced the tendency of 3- and 4-year-old children to conform. Participants were presented with 2 variants of a novel task in which they were required to judge which of 3 line-drawn tigers had the greatest number of stripes. The participants made their judgments in 2 contexts, first after viewing 5 informants perform the task incorrectly, and second without viewing the responses of other individuals. The informants comprised a group of familiar children, a group of unfamiliar children, a group of familiar adults, or a group of unfamiliar adults. The results showed that the children displayed selective conformity with respect to informant age, readily adopting the incorrect response when it was indicated by an adult majority, but failing to do so when the same incorrect response was indicated by a majority of children. In contrast the familiarity of the individuals comprising the majority had little influence on the tendency of children to conform. These results suggest that children are not blanket conformists, rather they respond selectively depending on characteristics of the individuals comprising the group majority.

  12. Molecular dynamics of 17α- and 21-hydroxy progesterone studied by NMR. Relation between molecule conformation and height of the barrier for methyl group reorientations in steroid compounds

    NASA Astrophysics Data System (ADS)

    Szyczewski, A.; Hołderna-Natkaniec, K.

    2005-01-01

    For the two steroid compounds 17αOH-progesterone and 21OH-progesterone, the activation energies of reorientations of the methyl groups have been determined. Their values together with results of the quantum chemical calculations permitted establishment of the sequence of the onset of the methyl group reorientations about the three-fold symmetry axis of the C-C bond. On the basis of the asymmetry parameters, the conformations of the hitherto studied pregnane derivatives and testosterone have been determined. It has been found that the conformation of ring A has dominant effect on the activation energies of the reorientation of C(19)H 3. The reorientation of the methyl group C(18)H 3 significantly depends on the conformation of the side chain 17β (torsional angle C(13)-C(17)-C(20)-O(20)) and the distance between C18 and O20. The study has proved that the 1H NMR method in combination with the quantum chemistry calculations and inelastic incoherent neutron scattering (IINS) are effective for prediction of the sequence of the methyl group reorientations about the three-fold symmetry axis.

  13. Use of single-strand conformation polymorphism of amplified 16S rDNA for grouping of bacteria isolated from foods.

    PubMed

    Takahashi, Hajime; Kimura, Bon; Tanaka, Yuichiro; Mori, Mayumi; Yokoi, Asami; Fujii, Tateo

    2008-04-01

    The grouping method for isolated strains from foods using single-strand conformation polymorphism (SSCP) after PCR amplification of a portion of 16S rDNA was developed. This method was able to group the strains from various food samples based on 16S rDNA sequence. As 97.8% of the isolated strains from various foods were grouped correctly, use of the PCR-SSCP method enables the prompt and labor-saving analysis of microbial population of food-derived bacterial strains. Advantages in speed and accuracy of bacterial population identification by the PCR-SSCP method have practical application for food suppliers and testing laboratories.

  14. Stable wormholes on a noncommutative-geometry background admitting a one-parameter group of conformal motions

    NASA Astrophysics Data System (ADS)

    Kuhfittig, P. K. F.

    2016-07-01

    When Morris and Thorne first proposed the possible existence of traversable wormholes, they adopted the following strategy: maintain complete control over the geometry, thereby leaving open the determination of the stress-energy tensor. In this paper we determine this tensor by starting with a noncommutative-geometry background and assuming that the static and spherically symmetric spacetime admits conformal motions. We have shown that the wormhole obtained can be made stable to linearized radial perturbations.

  15. Field theoretical Lie symmetry analysis: The Möbius group, exact solutions of conformal autonomous systems, and predictive model-building

    NASA Astrophysics Data System (ADS)

    Christodoulides, Kyriakos

    2014-07-01

    We study single and coupled first-order differential equations (ODEs) that admit symmetries with tangent vector fields, which satisfy the N-dimensional Cauchy-Riemann equations. In the two-dimensional case, classes of first-order ODEs which are invariant under Möbius transformations are explored. In the N dimensional case we outline a symmetry analysis method for constructing exact solutions for conformal autonomous systems. A very important aspect of this work is that we propose to extend the traditional technical usage of Lie groups to one that could provide testable predictions and guidelines for model-building and model-validation. The Lie symmetries in this paper are constrained and classified by field theoretical considerations and their phenomenological implications. Our results indicate that conformal transformations are appropriate for elucidating a variety of linear and nonlinear systems which could be used for, or inspire, future applications. The presentation is pragmatic and it is addressed to a wide audience.

  16. Conformational Changes in Orotidine 5’-Monophosphate Decarboxylase: A Structure-Based Explanation for How the 5’-Phosphate Group Activates the Enzyme†

    PubMed Central

    Desai, Bijoy J.; Wood, McKay; Fedorov, Alexander A.; Fedorov, Elena V.; Goryanova, Bogdana; Amyes, Tina L.; Richard, John P.; Almo, Steven C.; Gerlt, John A.

    2012-01-01

    The binding of a ligand to orotidine 5’-monophosphate decarboxylase (OMPDC) is accompanied by a conformational change from an open, inactive conformation (Eo) to a closed, active conformation (Ec). As the substrate traverses the reaction coordinate to form the stabilized vinyl carbanion/carbene intermediate, interactions are enforced that destabilize the carboxylate group of the substrate as well as stabilize the intermediate (in the Ec•S‡ complex). Focusing on the OMPDC from Methanothermobacter thermautotrophicus, the “remote” 5’-phosphate group of the substrate activates the enzyme 2.4 × 108-fold; the activation is equivalently described by an intrinsic binding energy (IBE) of 11.4 kcal/mol. We studied residues in the activation that 1) directly contact the 5’-phosphate group; 2) participate in a hydrophobic cluster near the base of the active site loop that sequesters the bound substrate from solvent; and 3) form hydrogen-bonding interactions across the interface between the “mobile” and “fixed” half-barrel domains of the (β/α8-barrel structure. Our data support a model in which the IBE provided by the 5’-phosphate group is used to enable interactions both near the N-terminus of the active site loop and across the domain interface that stabilize both the Ec•S and Ec•S‡ complexes relative to the Eo•S complex. The conclusion that the IBE of the 5’-phosphate group provides stabilization of both the Ec•S and Ec•S‡ complexes, not just the Ec•S‡ complex, is central to understanding the structural origins of enzymatic catalysis as well as the requirements for the de novo design of enzymes that catalyze novel reactions. PMID:23030629

  17. Understanding the NMR properties and conformational behavior of indole vs. azaindole group in protoberberines: NICS and NCS analysis

    NASA Astrophysics Data System (ADS)

    Kadam, Shivaji S.; Toušek, Jaromír; Maier, Lukáš; Pipíška, Matej; Sklenář, Vladimír; Marek, Radek

    2012-11-01

    We report here the preparation and the structural investigation into a series of 8-(indol-1-yl)-7,8-dihydroprotoberberine derivatives derived from berberine, palmatine, and coptisine. Structures of these new compounds were characterized mainly by 2D NMR spectroscopy and the conformational behavior was investigated by using methods of density-functional theory (DFT). PBE0/6-311+G** calculated NMR chemical shifts for selected derivatives correlate excellently with the experimental NMR data and support the structural conclusions drawn from the NMR experiments. An interesting role of the nitrogen atom in position N7' of the indole moiety in 8-(7-azaindol-1-yl)-7,8-dihydroprotoberberines as compared to other 8-indolyl derivatives is investigated in detail. The experimentally observed trends in NMR chemical shifts are rationalized by DFT calculations and analysis based on the nucleus-independent chemical shifts (NICS) and natural localized molecular orbitals (NLMOs).

  18. Conformal Nets II: Conformal Blocks

    NASA Astrophysics Data System (ADS)

    Bartels, Arthur; Douglas, Christopher L.; Henriques, André

    2017-03-01

    Conformal nets provide a mathematical formalism for conformal field theory. Associated to a conformal net with finite index, we give a construction of the `bundle of conformal blocks', a representation of the mapping class groupoid of closed topological surfaces into the category of finite-dimensional projective Hilbert spaces. We also construct infinite-dimensional spaces of conformal blocks for topological surfaces with smooth boundary. We prove that the conformal blocks satisfy a factorization formula for gluing surfaces along circles, and an analogous formula for gluing surfaces along intervals. We use this interval factorization property to give a new proof of the modularity of the category of representations of a conformal net.

  19. The influence of conformity and group identity on drink walking intentions: comparing intentions to drink walk across risky pedestrian crossing scenarios.

    PubMed

    McGhie, Alexandra; Lewis, Ioni; Hyde, Melissa K

    2012-03-01

    Despite the dangers associated with drink walking, limited research is currently available regarding the factors which influence individuals to engage in this risky behaviour. This study examined the influence of psychosocial factors upon individuals' intentions to drink walk across four experimental scenarios (and a control condition). Specifically, a 2×2 repeated measures design was utilised in which all of the scenarios incorporated a risky pedestrian crossing situation (i.e., a pedestrian crossing against a red man signal) but differed according to the level of group identity (i.e., low/strangers and high/friends) and conformity (low and high). Individuals were assessed for their intentions to drink walk within each of these different scenarios. Undergraduate students (N=151), aged 17-30 years, completed a questionnaire. Overall, most of the study's hypotheses were supported with individuals reporting the highest intentions to drink walk when in the presence of friends (i.e., high group identity) and their friends were said to be also crossing against the red man signal (i.e., high conformity). The findings may have significant implications for the design of countermeasures to reduce drink walking. For instance, the current findings would suggest that potentially effective strategies may be to promote resilience to peer influence as well as highlight the negative consequences associated with following the behaviour of other intoxicated pedestrians who are crossing against a red signal.

  20. Unprecedented conformational variability in main group inorganic chemistry: the tetraazidoarsenite and -antimonite salts A+ [M(N3)4]- (A = NMe4, PPh4, (Ph3P)2N; M = As, Sb), five similar salts, five different anion structures.

    PubMed

    Haiges, Ralf; Rahm, Martin; Christe, Karl O

    2013-01-07

    A unique example for conformational variability in inorganic main group chemistry has been discovered. The arrangement of the azido ligands in the pseudotrigonal bipyramidal [As(N(3))(4)](-) and [Sb(N(3))(4)](-) anions theoretically can give rise to seven different conformers which have identical MN(4) skeletons but different azido ligand arrangements and very similar energies. We have now synthesized and structurally characterized five of these conformers by subtle variations in the nature of the counterion. Whereas conformational variability is common in organic chemistry, it is rare in inorganic main group chemistry and is usually limited to two. To our best knowledge, the experimental observation of five distinct single conformers for the same type of anion is unprecedented. Theoretical calculations at the M06-2X/cc-pwCVTZ-PP level for all seven possible basic conformers show that (1) the energy differences between the five experimentally observed conformers are about 1 kcal/mol or less, and (2) the free monomeric anions are the energetically favored species in the gas phase and also for [As(N(3))(4)](-) in the solid state, whereas for [Sb(N(3))(4)](-) associated anions are energetically favored in the solid state and possibly in solutions. Raman spectroscopy shows that in the azide antisymmetric stretching region, the solid-state spectra are distinct for the different conformers, and permits their identification. The spectra of solutions are solvent dependent and differ from those of the solids indicating the presence of rapidly exchanging equilibria of different conformers. The only compound for which a solid with a single well-ordered conformer could not be isolated was [N(CH(3))(4)][As(N(3))(4)] which formed a viscous, room-temperature ionic liquid. Its Raman spectrum was identical to that of its CH(3)CN solution indicating the presence of an equilibrium of multiple conformers.

  1. Fourth 3D structure of the chitosan molecule: conformation of chitosan in its salts with medical organic acids having a phenyl group.

    PubMed

    Kawahara, Makoto; Yui, Toshifumi; Oka, Kunio; Zugenmaier, Peter; Suzuki, Shiho; Kitamura, Shinichi; Okuyama, Kenji; Ogawa, Kozo

    2003-07-01

    Chitosan salts with two medical organic acids having phenyl groups (salicylic and gentisic acids) exhibited fiber diffraction patterns of a new type of crystal which does not compare with known types I and II. The crystals, called type III salts, showed a fiber repeat of 2.550 nm and a meridional reflection at the 5th layer line. These results coupled with a conformational analysis indicate the chain conformation of chitosan with the salts to be a 5/3 helix, this helix differing from those of type I (an extended two-fold helix) and type II (a relaxed two-fold helix or a 4/1 helix). The fiber patterns of all the type III salts were similar. This observation has also been found with type II salts and is an indication that the acid ions are not arranged in regular positions in the crystals. A comparison of solid-state 13C-NMR spectra of the gentisic acid salt and the aspirin salt, which could not be crystallized, suggests that, in the latter salt, the chitosan molecules also formed a 5/3 helix.

  2. Energies and 2'-Hydroxyl Group Orientations of RNA Backbone Conformations. Benchmark CCSD(T)/CBS Database, Electronic Analysis, and Assessment of DFT Methods and MD Simulations.

    PubMed

    Mládek, Arnošt; Banáš, Pavel; Jurečka, Petr; Otyepka, Michal; Zgarbová, Marie; Šponer, Jiří

    2014-01-14

    Sugar-phosphate backbone is an electronically complex molecular segment imparting RNA molecules high flexibility and architectonic heterogeneity necessary for their biological functions. The structural variability of RNA molecules is amplified by the presence of the 2'-hydroxyl group, capable of forming multitude of intra- and intermolecular interactions. Bioinformatics studies based on X-ray structure database revealed that RNA backbone samples at least 46 substates known as rotameric families. The present study provides a comprehensive analysis of RNA backbone conformational preferences and 2'-hydroxyl group orientations. First, we create a benchmark database of estimated CCSD(T)/CBS relative energies of all rotameric families and test performance of dispersion-corrected DFT-D3 methods and molecular mechanics in vacuum and in continuum solvent. The performance of the DFT-D3 methods is in general quite satisfactory. The B-LYP-D3 method provides the best trade-off between accuracy and computational demands. B3-LYP-D3 slightly outperforms the new PW6B95-D3 and MPW1B95-D3 and is the second most accurate density functional of the study. The best agreement with CCSD(T)/CBS is provided by DSD-B-LYP-D3 double-hybrid functional, although its large-scale applications may be limited by high computational costs. Molecular mechanics does not reproduce the fine energy differences between the RNA backbone substates. We also demonstrate that the differences in the magnitude of the hyperconjugation effect do not correlate with the energy ranking of the backbone conformations. Further, we investigated the 2'-hydroxyl group orientation preferences. For all families, we conducted a QM and MM hydroxyl group rigid scan in gas phase and solvent. We then carried out set of explicit solvent MD simulations of folded RNAs and analyze 2'-hydroxyl group orientations of different backbone families in MD. The solvent energy profiles determined primarily by the sugar pucker match well with the

  3. Interaction between DNA and Drugs Having Protonable Basic Groups: Characterization through Affinity Constants, Drug Release Kinetics, and Conformational Changes.

    PubMed

    Alarcón, Liliana P; Baena, Yolima; Manzo, Rubén H

    2017-01-04

    This paper reports the in vitro characterization of the interaction between the phosphate groups of DNA and the protonated species of drugs with basic groups through the determination of the affinity constants, the reversibility of the interaction, and the effect on the secondary structure of the macromolecule. Affinity constants of the counterionic condensation DNA-drug were in the order of 10⁶. The negative electrokinetic potential of DNA decreased with the increase of the proportion of loading drugs. The drugs were slowly released from the DNA-drug complexes and had release kinetics consistent with the high degree of counterionic condensation. The circular dichroism profile of DNA was not modified by complexation with atenolol, lidocaine, or timolol, but was significantly altered by the more lipophilic drugs benzydamine and propranolol, revealing modifications in the secondary structure of the DNA. The in vitro characterization of such interactions provides a physicochemical basis that would contribute to identify the effects of this kind of drugs in cellular cultures, as well as side effects observed under their clinical use. Moreover, this methodology could also be projected to the fields of intracellular DNA transfection and the use of DNA as a carrier of active drugs.

  4. Transportation Conformity

    EPA Pesticide Factsheets

    This section provides information on: current laws, regulations and guidance, policy and technical guidance, project-level conformity, general information, contacts and training, adequacy review of SIP submissions

  5. Structures of a human blood group glycosyltransferase in complex with a photo-activatable UDP-Gal derivative reveal two different binding conformations

    PubMed Central

    Jørgensen, René; Batot, Gaëlle; Mannerstedt, Karin; Imberty, Anne; Breton, Christelle; Hindsgaul, Ole; Royant, Antoine; Palcic, Monica M.

    2014-01-01

    Glycosyltransferases (GTs) catalyse the sequential addition of monosaccharides to specific acceptor molecules and play major roles in key biological processes. GTs are classified into two main families depending on the inverted or retained stereochemistry of the glycosidic bond formed during the reaction. While the mechanism of inverting enzymes is well characterized, the precise nature of retaining GTs is still a matter of much debate. In an attempt to clarify this issue, studies were initiated to identify reaction-intermediate states by using a crystallographic approach based on caged substrates. In this paper, two distinct structures of AA(Gly)B, a dual-specificity blood group synthase, are described in complex with a UDP-galactose derivative in which the O6′′ atom is protected by a 2-nitrobenzyl group. The distinct conformations of the caged substrate in both structures of the enzyme illustrate the highly dynamic nature of its active site. An attempt was also made to photolyse the caged compound at low temperature, which unfortunately is not possible without damaging the uracil group as well. These results pave the way for kinetic crystallography experiments aiming at trapping and characterizing reaction-intermediate states in the mechanism of enzymatic glycosyl transfer. PMID:25084373

  6. Phase I Three-Dimensional Conformal Radiation Dose Escalation Study in Newly Diagnosed Glioblastoma: Radiation Therapy Oncology Group Trial 98-03

    SciTech Connect

    Tsien, Christina Moughan, Jennifer; Michalski, Jeff M.; Gilbert, Mark R.; Purdy, James; Simpson, Joseph; Kresel, John J.; Curran, Walter J.; Diaz, Aidnag; Mehta, Minesh P.

    2009-03-01

    Purpose: To evaluate in a Phase I trial the feasibility and toxicity of dose-escalated three-dimensional conformal radiotherapy (3D-CRT) concurrent with chemotherapy in patients with primary supratentorial glioblastoma (GBM). Methods and Materials: A total of 209 patients were enrolled. All received 46 Gy in 2-Gy fractions to the first planning target volume (PTV{sub 1}), defined as the gross tumor volume (GTV) plus 1.8 cm. A subsequent boost was given to PTV{sub 2}, defined as GTV plus 0.3 cm. Patients were stratified into two groups (Group 1: PTV{sub 2} <75 cm{sup 3}; Group 2: PTV{sub 2} {>=}75 cm{sup 3}). Four RT dose levels were evaluated: 66, 72, 78, and 84 Gy. Carmustine 80 mg/m{sup 2} was given during RT, then every 8 weeks for 6 cycles. Pretreatment characteristics were well balanced. Results: Acute and late Grade 3/4 RT-related toxicities were no more frequent at higher RT dose or with larger tumors. There were no dose-limiting toxicities (acute Grade {>=}3 irreversible central nervous system toxicities) observed on any dose level in either group. On the basis of the absence of dose-limiting toxicities, dose was escalated to 84 Gy in both groups. Late RT necrosis was noted at 66 Gy (1 patient), 72 Gy (2 patients), 78 Gy (2 patients), and 84 Gy (3 patients) in Group 1. In Group 2, late RT necrosis was noted at 78 Gy (1 patient) and 84 Gy (2 patients). Median time to RT necrosis was 8.8 months (range, 5.1-12.5 months). Median survival in Group 1 was 11.6-19.3 months. Median survival in Group 2 was 8.2-13.9 months. Conclusions: Our study shows the feasibility of delivering higher than standard (60 Gy) RT dose with concurrent chemotherapy for primary GBM, with an acceptable risk of late central nervous system toxicity.

  7. Protein covalent immobilization via its scarce thiol versus abundant amine groups: Effect on orientation, cell binding domain exposure and conformational lability.

    PubMed

    Ba, O M; Hindie, M; Marmey, P; Gallet, O; Anselme, K; Ponche, A; Duncan, A C

    2015-10-01

    Quantity, orientation, conformation and covalent linkage of naturally cell adhesive proteins adsorbed or covalently linked to a surface, are known to influence the preservation of their subsequent long term cell adhesion properties and bioactivity. In the present work, we explore two different strategies for the covalent linking of plasma fibronectin (pFN) - used as a cell adhesive model protein, onto a polystyrene (PS) surface. One is aimed at tethering the protein to the surface in a semi-oriented fashion (via one of the 4 free thiol reactive groups on the protein) with a heterofunctional coupling agent (SSMPB method). The other aims to immobilize the protein in a more random fashion by reaction between the abundant pendant primary amine bearing amino acids of the pFN and activated carboxylic surface functions obtained after glutaric anhydride surface treatment (GA method). The overall goal will be to verify the hypothesis of a correlation between covalent immobilization of a model cell adhesive protein to a PS surface in a semi-oriented configuration (versus randomly oriented) with promotion of enhanced exposure of the protein's cell binding domain. This in turn would lead to enhanced cell adhesion. Ideally the goal is to elaborate substrates exhibiting a long term stable protein monolayer with preserved cell adhesive properties and bioactivity for biomaterial and/or cell adhesion commercial plate applications. However, the initial restrictive objective of this paper is to first quantitatively and qualitatively investigate the reversibly (merely adsorbed) versus covalently irreversibly bound protein to the surface after the immobilization procedure. Although immobilized surface amounts were similar (close to the monolayer range) for all immobilization approaches, covalent grafting showed improved retention and stronger "tethering" of the pFN protein to the surface (roughly 40%) after SDS rinsing compared to that for mere adsorption (0%) suggesting an added value

  8. General Conformity

    EPA Pesticide Factsheets

    The General Conformity requirements ensure that the actions taken by federal agencies in nonattainment and maintenance areas do not interfere with a state’s plans to meet national standards for air quality.

  9. Conformal Infinity

    NASA Astrophysics Data System (ADS)

    Frauendiener, Jörg

    2004-12-01

    The notion of conformal infinity has a long history within the research in Einstein's theory of gravity. Today, "conformal infinity" is related to almost all other branches of research in general relativity, from quantisation procedures to abstract mathematical issues to numerical applications. This review article attempts to show how this concept gradually and inevitably evolved from physical issues, namely the need to understand gravitational radiation and isolated systems within the theory of gravitation, and how it lends itself very naturally to the solution of radiation problems in numerical relativity. The fundamental concept of null-infinity is introduced. Friedrich's regular conformal field equations are presented and various initial value problems for them are discussed. Finally, it is shown that the conformal field equations provide a very powerful method within numerical relativity to study global problems such as gravitational wave propagation and detection.

  10. Transition of hemoglobin between two tertiary conformations: determination of equilibrium and thermodynamic parameters from the reaction of 5,5'-dithiobis(2-nitrobenzoate) with the CysF9[93]beta sulfhydryl group.

    PubMed

    Okonjo, Kehinde Onwochei; Adediji, A Temilade; Fodeke, Adedayo A; Adeboye, Omolara; Ezeh, Chibuzo V

    2007-06-01

    The equilibrium constant of the reaction of 5,5'-dithiobis(2-nitrobenzoate) with the CysF9[93]beta sulfhydryl group of hemoglobin decreases by 2 to 3 orders of magnitude between pH 5.6 and 9. The reaction is coupled to the ionizations of two groups on the protein. At 25 degrees C one group has a pK(a) of 5.31+/-0.2 when hemoglobin is in its (tertiary) r conformation, typified by the thiolate anion form of CysF9[93]beta; this changes to 7.73+/-0.4 in the (tertiary) t conformation, typified by the mixed disulfide form of the sulfhydryl. The second group ionizes with a pK(a) of 7.11+/-0.4 in the r conformation; this changes to 8.38+/-0.2 in the t conformation. K(rt), the equilibrium constant for the r<-->t isomerization process, is 0.22+/-0.06. The standard enthalpy and entropy changes for the isomerization are DeltaH(o)(rt)=24.2 kJ mol(-1) and DeltaS(o)(rt)=68.8 JK(-1)mol(-1), respectively.

  11. Conformational analysis of thioglycoside derivatives of histo-blood group ABH antigens using an ab initio-derived reparameterization of MM4: implications for design of non-hydrolysable mimetics

    NASA Astrophysics Data System (ADS)

    Strino, Francesco; Lii, Jenn-Huei; Gabius, Hans-Joachim; Nyholm, Per-Georg

    2009-12-01

    Histo-blood group ABH antigens serve as recognition sites for infectious microorganisms and tissue lectins in intercellular communication, e.g. in tumor progression. Thus, they are of interest as a starting point for drug design. In this respect, potent non-hydrolysable derivatives such as thioglycosides are of special interest. As prerequisite to enable estimations of ligand properties relative to their natural counterparts, conformational properties of the thioglycosidic derivatives of ABH trisaccharides and their disaccharide units were calculated using systematic and filtered systematic searches with the MM4 force field. Parameters for the glycosidic torsions of thioglycosides were independently derived from ab initio calculations. The resulting energy deviations required a reparameterization of MM4 to a new parameter set called MM4R. The data sets obtained using MM4R reveal that the thioglycosides have somewhat increased levels of flexibility about the major low-energy conformations shared with the corresponding O-glycosides. In the trisaccharides, the thiosubstitution of the Gal[NAc]α1-3Gal linkage leads to a preference for a conformation which is the secondary minimum of the natural counterparts. This conformation also generates contacts between the N-acetyl group and the fucose moiety in the blood group A derivative. Calculations further indicate that thiosubstitution of only the Fucα1-2Gal linkage does not affect the conformational preferences compared to the natural trisaccharide. Thiosubstitution of both linkages in the trisaccharide results in increased flexibility but the favored conformation of the natural trisaccharides is preferred. The study suggests that thioglycoside derivatives of ABH antigens could have pharmaceutical interest as ligands of lectins and other carbohydrate-binding proteins.

  12. Rubipodanin A, the First Natural N-Desmonomethyl Rubiaceae-Type Cyclopeptide from Rubia podantha, Indicating an Important Role of the N9-Methyl Group in the Conformation and Bioactivity

    PubMed Central

    Zhao, Li-Mei; Chen, Xiao-Qiang; Zeng, Guang-Zhi; Tan, Ning-Hua

    2015-01-01

    One new cyclic hexapeptide named rubipodanin A (1), which is the first identified natural N-desmonomethyl Rubiaceae-type cyclopeptide, together with six known Rubiaceae-type cyclopeptides (2–7) were obtained using the TLC cyclopeptide protosite detection method with ninhydrin from the roots and rhizomes of Rubia podantha. The cyclopeptide structures were elucidated by extensive spectroscopic analysis, including 1D-NMR, 2D-NMR, IR, UV and MS. The solution conformation and biological activities of 1 and RA-V (4) were evaluated, and the results demonstrated that the N9-methyl group plays a vital role in the maintenance of the conformation and bioactivity. PMID:26694544

  13. Rubipodanin A, the First Natural N-Desmonomethyl Rubiaceae-Type Cyclopeptide from Rubia podantha, Indicating an Important Role of the N9-Methyl Group in the Conformation and Bioactivity.

    PubMed

    Wang, Zhe; Zhao, Si-Meng; Zhao, Li-Mei; Chen, Xiao-Qiang; Zeng, Guang-Zhi; Tan, Ning-Hua

    2015-01-01

    One new cyclic hexapeptide named rubipodanin A (1), which is the first identified natural N-desmonomethyl Rubiaceae-type cyclopeptide, together with six known Rubiaceae-type cyclopeptides (2-7) were obtained using the TLC cyclopeptide protosite detection method with ninhydrin from the roots and rhizomes of Rubia podantha. The cyclopeptide structures were elucidated by extensive spectroscopic analysis, including 1D-NMR, 2D-NMR, IR, UV and MS. The solution conformation and biological activities of 1 and RA-V (4) were evaluated, and the results demonstrated that the N9-methyl group plays a vital role in the maintenance of the conformation and bioactivity.

  14. Conformity, Anticonformity, andIndependence: Their Dimensionality and Generality

    ERIC Educational Resources Information Center

    Stricker, Lawrence J.; And Others

    1970-01-01

    Examines response to group pressure involving different judgments and social situations. One bipolar dimension included conformity and anticonformity, the other, conformity and independence. Tables, graphs, and bibliography. (RW)

  15. High Resolution Structures of the Human ABO(H) Blood Group Enzymes in Complex with Donor Analogs Reveal That the Enzymes Utilize Multiple Donor Conformations to Bind Substrates in a Stepwise Manner.

    PubMed

    Gagnon, Susannah M L; Meloncelli, Peter J; Zheng, Ruixiang B; Haji-Ghassemi, Omid; Johal, Asha R; Borisova, Svetlana N; Lowary, Todd L; Evans, Stephen V

    2015-11-06

    Homologous glycosyltransferases α-(1→3)-N-acetylgalactosaminyltransferase (GTA) and α-(1→3)-galactosyltransferase (GTB) catalyze the final step in ABO(H) blood group A and B antigen synthesis through sugar transfer from activated donor to the H antigen acceptor. These enzymes have a GT-A fold type with characteristic mobile polypeptide loops that cover the active site upon substrate binding and, despite intense investigation, many aspects of substrate specificity and catalysis remain unclear. The structures of GTA, GTB, and their chimeras have been determined to between 1.55 and 1.39 Å resolution in complex with natural donors UDP-Gal, UDP-Glc and, in an attempt to overcome one of the common problems associated with three-dimensional studies, the non-hydrolyzable donor analog UDP-phosphono-galactose (UDP-C-Gal). Whereas the uracil moieties of the donors are observed to maintain a constant location, the sugar moieties lie in four distinct conformations, varying from extended to the "tucked under" conformation associated with catalysis, each stabilized by different hydrogen bonding partners with the enzyme. Further, several structures show clear evidence that the donor sugar is disordered over two of the observed conformations and so provide evidence for stepwise insertion into the active site. Although the natural donors can both assume the tucked under conformation in complex with enzyme, UDP-C-Gal cannot. Whereas UDP-C-Gal was designed to be "isosteric" with natural donor, the small differences in structure imposed by changing the epimeric oxygen atom to carbon appear to render the enzyme incapable of binding the analog in the active conformation and so preclude its use as a substrate mimic in GTA and GTB.

  16. Selenoglycosides in silico: ab initio-derived reparameterization of MM4, conformational analysis using histo-blood group ABH antigens and lectin docking as indication for potential of bioactivity.

    PubMed

    Strino, Francesco; Lii, Jenn-Huei; Koppisetty, Chaitanya A K; Nyholm, Per-Georg; Gabius, Hans-Joachim

    2010-12-01

    The identification of glycan epitopes such as the histo-blood group ABH determinants as docking sites for bacterial/viral infections and signals in growth regulation fuels the interest to develop non-hydrolysable mimetics for therapeutic applications. Inevitably, the required substitution of the linkage oxygen atom will alter the derivative's topology. Our study addresses the question of the impact of substitution of oxygen by selenium. In order to characterize spatial parameters and flexibility of selenoglycosides, we first performed ab initio calculations on model compounds to refine the MM4 force field. The following application of the resulting MM4R version appears to reduce the difference to ab initio data when compared to using the MM4 estimator. Systematic conformational searches on the derivatives of histo-blood group ABH antigens revealed increased flexibility with acquisition of additional low-energy conformer(s), akin to the behavior of S-glycosides. Docking analysis using the Glide program for eight test cases indicated potential for bioactivity, giving further experimental investigation a clear direction to testing Se-glycosides as lectin ligands.

  17. Selenoglycosides in silico: ab initio-derived reparameterization of MM4, conformational analysis using histo-blood group ABH antigens and lectin docking as indication for potential of bioactivity

    NASA Astrophysics Data System (ADS)

    Strino, Francesco; Lii, Jenn-Huei; Koppisetty, Chaitanya A. K.; Nyholm, Per-Georg; Gabius, Hans-Joachim

    2010-12-01

    The identification of glycan epitopes such as the histo-blood group ABH determinants as docking sites for bacterial/viral infections and signals in growth regulation fuels the interest to develop non-hydrolysable mimetics for therapeutic applications. Inevitably, the required substitution of the linkage oxygen atom will alter the derivative's topology. Our study addresses the question of the impact of substitution of oxygen by selenium. In order to characterize spatial parameters and flexibility of selenoglycosides, we first performed ab initio calculations on model compounds to refine the MM4 force field. The following application of the resulting MM4R version appears to reduce the difference to ab initio data when compared to using the MM4 estimator. Systematic conformational searches on the derivatives of histo-blood group ABH antigens revealed increased flexibility with acquisition of additional low-energy conformer(s), akin to the behavior of S-glycosides. Docking analysis using the Glide program for eight test cases indicated potential for bioactivity, giving further experimental investigation a clear direction to testing Se-glycosides as lectin ligands.

  18. Conformational structure of the unsymmetrical monomethine cyanine bearing 2-azaazulene and 2-benzothiazole residues as terminal groups: Experimental and quantum-chemical investigation

    NASA Astrophysics Data System (ADS)

    Ryabitskii, Aleksey B.; Bricks, Julia L.; Kachkovskii, Aleksey D.; Chernega, Alexander N.; Vlasenko, Yurii G.

    2010-10-01

    Conformational features of unsymmetrical monomethine cyanine dye 2-[(2-butyl-1,3-dimethylcyclohepta[ c]pyrrol-6(2 H)-ylidene)methyl]-3-ethyl-1,3-benzothiazol-3-ium iodide-perchlorate have been investigated in solution by means of NMR spectroscopy and in the solid state by X-ray diffraction. The possibility of molecule conformational transformations was proved by scanning of potential energy surface along torsion angels. The corresponding energy barriers values have been calculated by means of DFT (B3LYP and M05-2X) methods. A comparison of structural parameters obtained by means of both methods was reported. The isomerization process was investigated by dynamic NMR spectroscopy. A comparison of 1H NMR spectra recorded in different solvents was performed. It was shown that in solution, intramolecular rotation around the bond С(6) аzaazulene-С methyne decelerated in NMR time scale took place. The data on dynamic behavior of dye molecules have been compared with the experimental X-ray data. Quantum-chemical calculation results are in agreement with the experimental data.

  19. Conformational properties of pyrethroids

    NASA Astrophysics Data System (ADS)

    Mullaley, Anne; Taylor, Robin

    1994-04-01

    X-ray database searches and theoretical potential-energy calculations indicate that the acid moieties of pyrethroid cyclopropanecarboxylate esters adopt a well-defined, relatively inflexible conformation. In contrast, the alcohol moieties can exist in many low-energy geometries. One of the least conformationally flexible pyrethroid alcohols is 4-phenylindan-2-ol. The approximate overall conformation adopted at the biological binding site by insecticidal esters of this alcohol can be deduced with reasonable confidence by molecular modelling. Graphics superposition of a variety of pyrethroid acids suggests the existence of a large but rather narrow pocket at the binding site, in which substituents at the 3-position of the cyclopropane ring can be accommodated. This pocket is asymmetric with respect to the plane of the cyclopropane ring, extending further on the side remote from the ester group. The effects of α-substitution on the insecticidal activity of pyrethroid esters may be due to the influence of substituents on the preferred conformations of the molecules. This hypothesis rationalises the paradoxical dependence on absolute stereochemistry of the activities of various allylbenzyl and cinnamyl alcohol derivatives.

  20. Conformal and projective symmetries in Newtonian cosmology

    NASA Astrophysics Data System (ADS)

    Duval, C.; Gibbons, G. W.; Horváthy, P. A.

    2017-02-01

    Definitions of non-relativistic conformal transformations are considered both in the Newton-Cartan and in the Kaluza-Klein-type Eisenhart/Bargmann geometrical frameworks. The symmetry groups that come into play are exemplified by the cosmological, and also the Newton-Hooke solutions of Newton's gravitational field equations. It is shown, in particular, that the maximal symmetry group of the standard cosmological model is isomorphic to the 13-dimensional conformal-Newton-Cartan group whose conformal-Bargmann extension is explicitly worked out. Attention is drawn to the appearance of independent space and time dilations, in contrast with the Schrödinger group or the Conformal Galilei Algebra.

  1. To conform or not to conform: spontaneous conformity diminishes the sensitivity to monetary outcomes.

    PubMed

    Yu, Rongjun; Sun, Sai

    2013-01-01

    When people have different opinions in a group, they often adjust their own attitudes and behaviors to match the group opinion, known as social conformity. The affiliation account of normative conformity states that people conform to norms in order to 'fit in', whereas the accuracy account of informative conformity posits that the motive to learn from others produces herding. Here, we test another possibility that following the crowd reduces the experienced negative emotion when the group decision turns out to be a bad one. Using event related potential (ERP) combined with a novel group gambling task, we found that participants were more likely to choose the option that was predominately chosen by other players in previous trials, although there was little explicit normative pressure at the decision stage and group choices were not informative. When individuals' choices were different from others, the feedback related negativity (FRN), an ERP component sensitive to losses and errors, was enhanced, suggesting that being independent is aversive. At the outcome stage, the losses minus wins FRN effect was significantly reduced following conformity choices than following independent choices. Analyses of the P300 revealed similar patterns both in the response and outcome period. Our study suggests that social conformity serves as an emotional buffer that protects individuals from experiencing strong negative emotion when the outcomes are bad.

  2. To Conform or Not to Conform: Spontaneous Conformity Diminishes the Sensitivity to Monetary Outcomes

    PubMed Central

    2013-01-01

    When people have different opinions in a group, they often adjust their own attitudes and behaviors to match the group opinion, known as social conformity. The affiliation account of normative conformity states that people conform to norms in order to ‘fit in’, whereas the accuracy account of informative conformity posits that the motive to learn from others produces herding. Here, we test another possibility that following the crowd reduces the experienced negative emotion when the group decision turns out to be a bad one. Using event related potential (ERP) combined with a novel group gambling task, we found that participants were more likely to choose the option that was predominately chosen by other players in previous trials, although there was little explicit normative pressure at the decision stage and group choices were not informative. When individuals' choices were different from others, the feedback related negativity (FRN), an ERP component sensitive to losses and errors, was enhanced, suggesting that being independent is aversive. At the outcome stage, the losses minus wins FRN effect was significantly reduced following conformity choices than following independent choices. Analyses of the P300 revealed similar patterns both in the response and outcome period. Our study suggests that social conformity serves as an emotional buffer that protects individuals from experiencing strong negative emotion when the outcomes are bad. PMID:23691242

  3. Molecular subtyping of human T-cell lymphotropic virus type 2 by single-strand conformation polymorphism analysis. Retrovirus Epidemiology Donor Study Group.

    PubMed Central

    Heneine, W; Switzer, W M; Busch, M; Khabbaz, R F; Kaplan, J E

    1995-01-01

    Molecular subtyping of human T-cell lymphotropic virus type 2 (HTLV-2) by the currently used method of restriction fragment length polymorphism analysis may not be sufficiently discriminatory for transmission studies because of the predominance of single restriction types in various HTLV-2-infected populations. The utility of single-strand conformations polymorphism (SSCP) analysis was evaluated as a tool to improve the sensitivity of the subtyping of HTLV-2. The assay was designed to target a highly variable region in the long terminal repeat and was shown to be able to detect single nucleotide changes in cloned HTLV-2 sequences. Analysis of 52 HTLV-2 samples, of which 32 were from 16 sex partner pairs (16 males, 16 females), showed nine different SSCP patterns. Identical SSCP results were obtained for each of the 16 couples, suggesting the presence of similar viral genotypes and, therefore, supporting the likelihood of sexual transmission of HTLV-2 in each of these couples. Furthermore, SSCP analysis of seven HTLV-2 samples of the same restriction type (b5) showed five different SSCP patterns. Nucleotide sequencing of two samples with distinct SSCP patterns confirmed the sequence differences. SSCP provides a facile and discriminatory tool for the differentiation of HTLV-2 strains, including those previously indistinguishable by restriction fragment length polymorphism. PMID:8586713

  4. Congested ferrocenyl polyphosphanes bearing electron-donating or electron-withdrawing phosphanyl groups: assessment of metallocene conformation from NMR spin couplings and use in palladium-catalyzed chloroarenes activation.

    PubMed

    Mom, Sophal; Beaupérin, Matthieu; Roy, David; Royer, Sylviane; Amardeil, Régine; Cattey, Hélène; Doucet, Henri; Hierso, J-C

    2011-11-21

    The synthesis of novel substituted cyclopentadienyl salts that incorporate both a congested branched alkyl group (tert-butyl, (triphenyl)methyl, or tri(4-tert-butyl)phenylmethyl) and a phosphanyl group is reported. The introduction of either electron-withdrawing or electron-donating substituents (furyl, i-propyl, cyclohexyl, tert-butyl) on P atoms was generally achieved in high yield. The modular synthesis of ferrocenyl polyphosphanes from an assembly of these cyclopentadienyl salts was investigated, leading to the formation of new triphosphanes (denoted as 9-12) and diphosphanes (denoted as 14-16). The resulting phosphanes are not sensitive to air or moisture, even when electron-rich substituents are present. This set of polyphosphanes displays varied conformational features, which are discussed in the light of their multinuclear NMR characterization in solution and of the X-ray solid state structure of the representative triphosphane 1,2-bis(diphenylphosphanyl)-1'-(diisopropylphosphanyl)-3'-(triphenyl)methyl-4-tert-butyl ferrocene, 11. In particular, the existence of a range of significantly different nonbonded ("through-space", TS) spin-spin coupling constants between heteroannular P atoms, for the triphosphanes of this class, allowed their preferred conformation in solution to be appraised. The study evidences an unanticipated flexibility of the ferrocene platform, despite the presence of very congested tert-butyl and trityl groups. Herein, we show that, contrary to our first belief, the preferred conformation for the backbone of ferrocenyl polyphosphanes can not only depend on the hindrance of the groups decorating the cyclopentadienyl rings but is also a function of the substituents of the phosphanyl groups. The interest of these robust phosphanes as ligands was illustrated in palladium catalysis for the arylation of n-butyl furan with chloroarenes, using direct C-H activation of the heteroaromatic in the presence of low metal/ligand loadings (0.5-1.0 mol

  5. Conformations of organophosphine oxides

    SciTech Connect

    De Silva, Nuwan; Zahariev, Federico; Hay, Benjamin P.; Gordon, Mark S.; Windus, Theresa L.

    2015-07-17

    The conformations of a series of organophosphine oxides, OP(CH3)2R, where R = methyl, ethyl, isopropyl, tert-butyl, vinyl, and phenyl, are predicted using the MP2/cc-pVTZ level of theory. Comparison of potential energy surfaces for rotation about P–C bonds with crystal structure data reveals a strong correlation between predicted location and energetics of minima and histograms of dihedral angle distributions observed in the solid state. In addition, the most stable conformers are those that minimize the extent of steric repulsion between adjacent rotor substituents, and the torsional barriers tend to increase with the steric bulk of the rotating alkyl group. MM3 force field parameters were adjusted to fit the MP2 results, providing a fast and accurate model for predicting organophosphine oxides shapes—an essential part of understanding the chemistry of these compounds. As a result, the predictive power of the modified MM3 model was tested against MP2/cc-pVTZ conformations for triethylphosphine oxide, OP(CH2CH3)3, and triphenylphosphine oxide, OP(Ph)3.

  6. Conformations of organophosphine oxides

    DOE PAGES

    De Silva, Nuwan; Zahariev, Federico; Hay, Benjamin P.; ...

    2015-07-17

    The conformations of a series of organophosphine oxides, OP(CH3)2R, where R = methyl, ethyl, isopropyl, tert-butyl, vinyl, and phenyl, are predicted using the MP2/cc-pVTZ level of theory. Comparison of potential energy surfaces for rotation about P–C bonds with crystal structure data reveals a strong correlation between predicted location and energetics of minima and histograms of dihedral angle distributions observed in the solid state. In addition, the most stable conformers are those that minimize the extent of steric repulsion between adjacent rotor substituents, and the torsional barriers tend to increase with the steric bulk of the rotating alkyl group. MM3 forcemore » field parameters were adjusted to fit the MP2 results, providing a fast and accurate model for predicting organophosphine oxides shapes—an essential part of understanding the chemistry of these compounds. As a result, the predictive power of the modified MM3 model was tested against MP2/cc-pVTZ conformations for triethylphosphine oxide, OP(CH2CH3)3, and triphenylphosphine oxide, OP(Ph)3.« less

  7. Conformation Distributions in Adsorbed Proteins.

    NASA Astrophysics Data System (ADS)

    Meuse, Curtis W.; Hubbard, Joseph B.; Vrettos, John S.; Smith, Jackson R.; Cicerone, Marcus T.

    2007-03-01

    While the structural basis of protein function is well understood in the biopharmaceutical and biotechnology industries, few methods for the characterization and comparison of protein conformation distributions are available. New methods capable of measuring the stability of protein conformations and the integrity of protein-protein, protein-ligand and protein-surface interactions both in solution and on surfaces are needed to help the development of protein-based products. We are developing infrared spectroscopy methods for the characterization and comparison of molecular conformation distributions in monolayers and in solutions. We have extracted an order parameter describing the orientational and conformational variations of protein functional groups around the average molecular values from a single polarized spectrum. We will discuss the development of these methods and compare them to amide hydrogen/deuterium exchange methods for albumin in solution and on different polymer surfaces to show that our order parameter is related to protein stability.

  8. Conformity to Peer Pressure in Preschool Children

    ERIC Educational Resources Information Center

    Haun, Daniel B. M.; Tomasello, Michael

    2011-01-01

    Both adults and adolescents often conform their behavior and opinions to peer groups, even when they themselves know better. The current study investigated this phenomenon in 24 groups of 4 children between 4;2 and 4;9 years of age. Children often made their judgments conform to those of 3 peers, who had made obviously erroneous but unanimous…

  9. Scale invariance vs conformal invariance

    NASA Astrophysics Data System (ADS)

    Nakayama, Yu

    2015-03-01

    In this review article, we discuss the distinction and possible equivalence between scale invariance and conformal invariance in relativistic quantum field theories. Under some technical assumptions, we can prove that scale invariant quantum field theories in d = 2 space-time dimensions necessarily possess the enhanced conformal symmetry. The use of the conformal symmetry is well appreciated in the literature, but the fact that all the scale invariant phenomena in d = 2 space-time dimensions enjoy the conformal property relies on the deep structure of the renormalization group. The outstanding question is whether this feature is specific to d = 2 space-time dimensions or it holds in higher dimensions, too. As of January 2014, our consensus is that there is no known example of scale invariant but non-conformal field theories in d = 4 space-time dimensions under the assumptions of (1) unitarity, (2) Poincaré invariance (causality), (3) discrete spectrum in scaling dimensions, (4) existence of scale current and (5) unbroken scale invariance in the vacuum. We have a perturbative proof of the enhancement of conformal invariance from scale invariance based on the higher dimensional analogue of Zamolodchikov's c-theorem, but the non-perturbative proof is yet to come. As a reference we have tried to collect as many interesting examples of scale invariance in relativistic quantum field theories as possible in this article. We give a complementary holographic argument based on the energy-condition of the gravitational system and the space-time diffeomorphism in order to support the claim of the symmetry enhancement. We believe that the possible enhancement of conformal invariance from scale invariance reveals the sublime nature of the renormalization group and space-time with holography. This review is based on a lecture note on scale invariance vs conformal invariance, on which the author gave lectures at Taiwan Central University for the 5th Taiwan School on Strings and

  10. In Vivo Phenotypic Screening for Treating Chronic Neuropathic Pain: Modification of C2-Arylethynyl Group of Conformationally Constrained A3 Adenosine Receptor Agonists

    PubMed Central

    2015-01-01

    (N)-Methanocarba adenosine 5′-methyluronamides containing 2-arylethynyl groups were synthesized as A3 adenosine receptor (AR) agonists and screened in vivo (po) for reduction of neuropathic pain. A small N6-methyl group maintained binding affinity, with human > mouse A3AR and MW < 500 and other favorable physicochemical properties. Emax (maximal efficacy in a mouse chronic constriction injury pain model) of previously characterized A3AR agonist, 2-(3,4-difluorophenylethynyl)-N6-(3-chlorobenzyl) derivative 6a, MRS5698, was surpassed. More efficacious analogues (in vivo) contained the following C2-arylethynyl groups: pyrazin-2-yl 23 (binding Ki, hA3AR, nM 1.8), fur-2-yl 27 (0.6), thien-2-yl 32 (0.6) and its 5-chloro 33, MRS5980 (0.7) and 5-bromo 34 (0.4) equivalents, and physiologically unstable ferrocene 36, MRS5979 (2.7). 33 and 36 displayed particularly long in vivo duration (>3 h). Selected analogues were docked to an A3AR homology model to explore the environment of receptor-bound C2 and N6 groups. Various analogues bound with μM affinity at off-target biogenic amine (M2, 5HT2A, β3, 5HT2B, 5HT2C, and α2C) or other receptors. Thus, we have expanded the structural range of orally active A3AR agonists for chronic pain treatment. PMID:25422861

  11. Influence of length and conformation of saccharide head groups on the mechanics of glycolipid membranes: Unraveled by off-specular neutron scattering

    SciTech Connect

    Yamamoto, Akihisa E-mail: tanaka@uni-heidelberg.de; Tanaka, Motomu E-mail: tanaka@uni-heidelberg.de; Abuillan, Wasim; Körner, Alexander; Burk, Alexandra S.; Ries, Annika; Werz, Daniel B.; Demé, Bruno

    2015-04-21

    The mechanical properties of multilayer stacks of Gb3 glycolipid that play key roles in metabolic disorders (Fabry disease) were determined quantitatively by using specular and off-specular neutron scattering. Because of the geometry of membrane stacks deposited on planar substrates, the scattered intensity profile was analyzed in a 2D reciprocal space map as a function of in-plane and out-of-plane scattering vector components. The two principal mechanical parameters of the membranes, namely, bending rigidity and compression modulus, can be quantified by full calculation of scattering functions with the aid of an effective cut-off radius that takes the finite sample size into consideration. The bulkier “bent” Gb3 trisaccharide group makes the membrane mechanics distinctly different from cylindrical disaccharide (lactose) head groups and shorter “bent” disaccharide (gentiobiose) head groups. The mechanical characterization of membranes enriched with complex glycolipids has high importance in understanding the mechanisms of diseases such as sphingolipidoses caused by the accumulation of non-degenerated glycosphingolipids in lysosomes or inhibition of protein synthesis triggered by the specific binding of Shiga toxin to Gb3.

  12. Influence of length and conformation of saccharide head groups on the mechanics of glycolipid membranes: Unraveled by off-specular neutron scattering

    NASA Astrophysics Data System (ADS)

    Yamamoto, Akihisa; Abuillan, Wasim; Burk, Alexandra S.; Körner, Alexander; Ries, Annika; Werz, Daniel B.; Demé, Bruno; Tanaka, Motomu

    2015-04-01

    The mechanical properties of multilayer stacks of Gb3 glycolipid that play key roles in metabolic disorders (Fabry disease) were determined quantitatively by using specular and off-specular neutron scattering. Because of the geometry of membrane stacks deposited on planar substrates, the scattered intensity profile was analyzed in a 2D reciprocal space map as a function of in-plane and out-of-plane scattering vector components. The two principal mechanical parameters of the membranes, namely, bending rigidity and compression modulus, can be quantified by full calculation of scattering functions with the aid of an effective cut-off radius that takes the finite sample size into consideration. The bulkier "bent" Gb3 trisaccharide group makes the membrane mechanics distinctly different from cylindrical disaccharide (lactose) head groups and shorter "bent" disaccharide (gentiobiose) head groups. The mechanical characterization of membranes enriched with complex glycolipids has high importance in understanding the mechanisms of diseases such as sphingolipidoses caused by the accumulation of non-degenerated glycosphingolipids in lysosomes or inhibition of protein synthesis triggered by the specific binding of Shiga toxin to Gb3.

  13. NMR structure of the 5' splice site in the group IIB intron Sc.ai5γ--conformational requirements for exon-intron recognition.

    PubMed

    Kruschel, Daniela; Skilandat, Miriam; Sigel, Roland K O

    2014-03-01

    A crucial step of the self-splicing reaction of group II intron ribozymes is the recognition of the 5' exon by the intron. This recognition is achieved by two regions in domain 1 of the intron, the exon-binding sites EBS1 and EBS2 forming base pairs with the intron-binding sites IBS1 and IBS2 located at the end of the 5' exon. The complementarity of the EBS1•IBS1 contact is most important for ensuring site-specific cleavage of the phosphodiester bond between the 5' exon and the intron. Here, we present the NMR solution structures of the d3' hairpin including EBS1 free in solution and bound to the IBS1 7-mer. In the unbound state, EBS1 is part of a flexible 11-nucleotide (nt) loop. Binding of IBS1 restructures and freezes the entire loop region. Mg(2+) ions are bound near the termini of the EBS1•IBS1 helix, stabilizing the interaction. Formation of the 7-bp EBS1•IBS1 helix within a loop of only 11 nt forces the loop backbone to form a sharp turn opposite of the splice site, thereby presenting the scissile phosphate in a position that is structurally unique.

  14. Can the renormalization group improved effective potential be used to estimate the Higgs mass in the conformal limit of the standard model?

    SciTech Connect

    Chishtie, F. A.; Jia, J.; Hanif, T.; Mann, R. B.; McKeon, D. G. C.; Sherry, T. N.; Steele, T. G.

    2011-05-15

    We consider the effective potential V in the standard model with a single Higgs doublet in the limit that the only mass scale {mu} present is radiatively generated. Using a technique that has been shown to determine V completely in terms of the renormalization group (RG) functions when using the Coleman-Weinberg renormalization scheme, we first sum leading-log (LL) contributions to V using the one loop RG functions, associated with five couplings (the top quark Yukawa coupling x, the quartic coupling of the Higgs field y, the SU(3) gauge coupling z, and the SU(2)xU(1) couplings r and s). We then employ the two loop RG functions with the three couplings x, y, z to sum the next-to-leading-log (NLL) contributions to V and then the three to five loop RG functions with one coupling y to sum all the N{sup 2}LL...N{sup 4}LL contributions to V. In order to compute these sums, it is necessary to convert those RG functions that have been originally computed explicitly in the minimal subtraction scheme to their form in the Coleman-Weinberg scheme. The Higgs mass can then be determined from the effective potential: the LL result is m{sub H}=219 GeV/c{sup 2} and decreases to m{sub H}=188 GeV/c{sup 2} at N{sup 2}LL order and m{sub H}=163 GeV/c{sup 2} at N{sup 4}LL order. No reasonable estimate of m{sub H} can be made at orders V{sub NLL} or V{sub N}{sup 3}{sub LL} since the method employed gives either negative or imaginary values for the quartic scalar coupling. The fact that we get reasonable values for m{sub H} from the LL, N{sup 2}LL, and N{sup 4}LL approximations is taken to be an indication that this mechanism for spontaneous symmetry breaking is in fact viable, though one in which there is slow convergence towards the actual value of m{sub H}. The mass 163 GeV/c{sup 2} is argued to be an upper bound on m{sub H}.

  15. Adjuvant Chemoradiation for Gastric Cancer Using Epirubicin, Cisplatin, and 5-Fluorouracil Before and After Three-Dimensional Conformal Radiotherapy With Concurrent Infusional 5-Fluorouracil: A Multicenter Study of the Trans-Tasman Radiation Oncology Group

    SciTech Connect

    Leong, Trevor; Joon, Daryl Lim; Willis, David; Jayamoham, Jayasingham; Spry, Nigel; Harvey, Jennifer; Di Iulio, Juliana; Milner, Alvin; Mann, G. Bruce; Michael, Michael

    2011-03-01

    Purpose: The INT0116 study has established postoperative chemoradiotherapy as the standard of care for completely resected gastric adenocarcinoma. However, the optimal chemoradiation regimen remains to be defined. We conducted a prospective, multicenter study to evaluate an alternative chemoradiation regimen that combines more current systemic treatment with modern techniques of radiotherapy delivery. Methods and Materials: Patients with adenocarcinoma of the stomach who had undergone an R0 resection were eligible. Adjuvant therapy consisted of one cycle of epirubicin, cisplatin, and 5-FU (ECF), followed by radiotherapy with concurrent infusional 5-FU, and then two additional cycles of ECF. Radiotherapy was delivered using precisely defined, multiple-field, three-dimensional conformal techniques. Results: A total of 54 assessable patients were enrolled from 19 institutions. The proportion of patients commencing Cycles 1, 2, and 3 of ECF chemotherapy were 100%, 81%, and 67% respectively. In all, 94% of patients who received radiotherapy completed treatment as planned. Grade 3/4 neutropenia occurred in 66% of patients with 7.4% developing febrile neutropenia. Most neutropenic episodes (83%) occurred in the post-radiotherapy period during cycles 2 and 3 of ECF. Grade 3/4 gastrointestinal toxicity occurred in 28% of patients. In all, 35% of radiotherapy treatment plans contained protocol deviations that were satisfactorily amended before commencement of treatment. At median follow-up of 36 months, the 3-year overall survival rate was estimated at 61.6%. Conclusions: This adjuvant regimen using ECF before and after three-dimensional conformal chemoradiation is feasible and can be safely delivered in a cooperative group setting. A regimen similar to this is currently being compared with the INT0116 regimen in a National Cancer Institute-sponsored, randomized Phase III trial.

  16. Conformity and Anticonformity Among Americans and Chinese

    ERIC Educational Resources Information Center

    Meade, Robert D.; Barnard, William A.

    1973-01-01

    Using a three-variable design, this study investigated conformity to male and female group pressures among Chinese and American male college students. Americans showed a greater tendency toward anticonformity than did Chinese. (JB)

  17. EXPERIMENTS IN GROUP PREDICTION,

    DTIC Science & Technology

    GROUP DYNAMICS, *ATTITUDES(PSYCHOLOGY)), (*PREDICTIONS, ACCURACY), PROBLEM SOLVING, DECISION MAKING, CONFORMITY , QUESTIONNAIRES, EXPERIMENTAL DESIGN, SOCIAL PSYCHOLOGY, FEEDBACK, RELIABILITY, STATISTICAL ANALYSIS

  18. Electrophysiological precursors of social conformity.

    PubMed

    Shestakova, Anna; Rieskamp, Jörg; Tugin, Sergey; Ossadtchi, Alexey; Krutitskaya, Janina; Klucharev, Vasily

    2013-10-01

    Humans often change their beliefs or behavior due to the behavior or opinions of others. This study explored, with the use of human event-related potentials (ERPs), whether social conformity is based on a general performance-monitoring mechanism. We tested the hypothesis that conflicts with a normative group opinion evoke a feedback-related negativity (FRN) often associated with performance monitoring and subsequent adjustment of behavior. The experimental results show that individual judgments of facial attractiveness were adjusted in line with a normative group opinion. A mismatch between individual and group opinions triggered a frontocentral negative deflection with the maximum at 200 ms, similar to FRN. Overall, a conflict with a normative group opinion triggered a cascade of neuronal responses: from an earlier FRN response reflecting a conflict with the normative opinion to a later ERP component (peaking at 380 ms) reflecting a conforming behavioral adjustment. These results add to the growing literature on neuronal mechanisms of social influence by disentangling the conflict-monitoring signal in response to the perceived violation of social norms and the neural signal of a conforming behavioral adjustment.

  19. Standing in the Hallway Improves Students' Understanding of Conformity

    ERIC Educational Resources Information Center

    Lawson, Timothy J.; Haubner, Richard R.; Bodle, James H.

    2013-01-01

    To help beginning psychology students understand how they are influenced by social pressures to conform, we developed a demonstration designed to elicit their conformity to a small group of students standing in the hallway before class. Results showed the demonstration increased students' recognition of their own tendency to conform, knowledge of…

  20. The Conformal Bootstrap

    NASA Astrophysics Data System (ADS)

    Simmons-Duffin, David

    These notes are from courses given at TASI and the Advanced Strings School in summer 2015. Starting from principles of quantum field theory and the assumption of a traceless stress tensor, we develop the basics of conformal field theory, including conformal Ward identities, radial quantization, reection positivity, the operator product expansion, and conformal blocks. We end with an introduction to numerical bootstrap methods, focusing on the 2d and 3d Ising models.

  1. The Conformational Behaviour of the Odorant Dihydrocarveol

    NASA Astrophysics Data System (ADS)

    Loru, Donatella; Jarman, Natasha; Sanz, M. Eugenia

    2016-06-01

    The odorant dihydrocarveol (C10H18O) has been investigated in the gas phase using a 2-8 GHz chirped-pulse Fourier transform microwave spectrometer. Dihydrocarveol was purchased as a mixture of n-, iso-, neo-, and neoiso- isomers. The sample was placed in a bespoke heating nozzle at about 85°C and seeded in Ne at 5 bar. Three conformers were observed and their rotational constants were determined. By comparing the experimental rotational constants with those calculated ab initio the three conformers were identified as belonging to n-dihydrocarveol. In all three conformers the isopropenyl group is in equatorial position with respect to the six-membered ring, and the OH group maintains the same configuration. The conformers differ in the orientation of the isopropenyl group.

  2. The Conformational Landscape of Serinol

    NASA Astrophysics Data System (ADS)

    Sanz, M. Eugenia; Loru, Donatella; Peña, Isabel; Alonso, José L.

    2014-06-01

    The rotational spectrum of the amino alcohol serinol CH_2OH--CH(NH_2)--CH_2OH, which constitutes the hydrophilic head of the lipid sphingosine, has been investigated using chirped-pulsed Fourier transform microwave spectroscopy in combination with laser ablation Five different forms of serinol have been observed and conclusively identified by the comparison between the experimental values of their rotational and 14N quadrupole coupling constants and those predicted by ab initio calculations. In all observed conformers several hydrogen bonds are established between the two hydroxyl groups and the amino groups in a chain or circular arrangement. The most abundant conformer is stabilised by O--H···N and N--H···O hydrogen bonds forming a chain rather than a cycle. One of the detected conformers presents a tunnelling motion of the hydrogen atoms of the functional groups similar to that observed in glycerol. S. Mata, I. Peña, C. Cabezas, J. C. López, J. L. Alonso, J. Mol. Spectrosc. 2012, 280, 91 V. V. Ilyushin, R. A. Motiyenko, F. J. Lovas, D. F. Plusquellic, J. Mol. Spectrosc. 2008, 251, 129.

  3. [Dosimetric evaluation of conformal radiotherapy: conformity factor].

    PubMed

    Oozeer, R; Chauvet, B; Garcia, R; Berger, C; Felix-Faure, C; Reboul, F

    2000-01-01

    The aim of three-dimensional conformal therapy (3DCRT) is to treat the Planning Target Volume (PTV) to the prescribed dose while reducing doses to normal tissues and critical structures, in order to increase local control and reduce toxicity. The evaluation tools used for optimizing treatment techniques are three-dimensional visualization of dose distributions, dose-volume histograms, tumor control probabilities (TCP) and normal tissue complication probabilities (NTCP). These tools, however, do not fully quantify the conformity of dose distributions to the PTV. Specific tools were introduced to measure this conformity for a given dose level. We have extended those definitions to different dose levels, using a conformity index (CI). CI is based on the relative volumes of PTV and outside the PTV receiving more than a given dose. This parameter has been evaluated by a clinical study including 82 patients treated for lung cancer and 82 patients treated for prostate cancer. The CI was low for lung dosimetric studies (0.35 at the prescribed dose 66 Gy) due to build-up around the GTV and to spinal cord sparing. For prostate dosimetric studies, the CI was higher (0.57 at the prescribed dose 70 Gy). The CI has been used to compare treatment plans for lung 3DCRT (2 vs 3 beams) and prostate 3DCRT (4 vs 7 beams). The variation of CI with dose can be used to optimize dose prescription.

  4. Conformal differential invariants

    NASA Astrophysics Data System (ADS)

    Kruglikov, Boris

    2017-03-01

    We compute the Hilbert polynomial and the Poincaré function counting the number of fixed jet-order differential invariants of conformal metric structures modulo local diffeomorphisms, and we describe the field of rational differential invariants separating generic orbits of the diffeomorphism pseudogroup action. This resolves the local recognition problem for conformal structures.

  5. Conformations of Substituted Ethanes.

    ERIC Educational Resources Information Center

    Kingsbury, Charles A.

    1979-01-01

    Reviews state-of-the-art of conformational analysis and factors which affect it. Emphasizes sp-3 hybridized acrylic molecules. Provides examples on the importance of certain factors in determining conformation. Purpose, is to provide examples for examination questions. (Author/SA)

  6. pH-induced conformational changes in human ABO(H) blood group glycosyltransferases confirm the importance of electrostatic interactions in the formation of the semi-closed state.

    PubMed

    Johal, Asha R; Blackler, Ryan J; Alfaro, Javier A; Schuman, Brock; Borisova, Svetlana; Evans, Stephen V

    2014-03-01

    The homologous human ABO(H) A and B blood group glycosyltransferases GTA and GTB have two mobile polypeptide loops surrounding their active sites that serve to allow substrate access and product egress and to recognize and sequester substrates for catalysis. Previous studies have established that these enzymes can move from the "open" state to the "semi-closed" then "closed" states in response to addition of a substrate. The contribution of electrostatic interactions to these conformational changes has now been demonstrated by the determination at various pH of the structures of GTA, GTB and the chimeric enzyme ABBA. At near-neutral pH, GTA displays the closed state in which both mobile loops order around the active site, whereas ABBA and GTB display the open state. At low pH, the apparent protonation of the DXD motif in GTA leads to the expulsion of the donor analog to yield the open state, whereas at high pH, both ABBA and GTB form the semi-closed state in which the first mobile loop becomes an ordered α-helix. Step-wise deprotonation of GTB in increments of 0.5 between pH 6.5 and 10.0 shows that helix ordering is gradual, which indicates that the formation of the semi-closed state is dependent on electrostatic forces consistent with the binding of substrate. Spectropolarimetric studies of the corresponding stand-alone peptide in solution reveal no tendency toward helix formation from pH 7.0 to 10.0, which shows that pH-dependent stability is a product of the larger protein environment and underlines the importance of substrate in active site ordering.

  7. Prospective Study of Alternating Chemoradiotherapy Consisting of Extended-Field Dynamic Conformational Radiotherapy and Systemic Chemotherapy Using 5-FU and Nedaplatin for Patients in High-Risk Group With Cervical Carcinoma

    SciTech Connect

    Kodaira, Takeshi Fuwa, Nobukazu; Nakanishi, Toru; Tachibana, Hiroyuki; Nakamura, Tatsuya; Tomita, Natsuo; Nakahara, Rie; Inokuchi, Haruo

    2009-01-01

    Purpose: To assess the efficacy of alternating chemoradiotherapy combined with extended-field conformal radiotherapy for patients with high-risk cervical cancer. Methods and Materials: Patients with previously untreated cervical cancer, with Stage III/IVA disease, or Stage IB/II with high-risk factor (primary tumor diameter {>=}50 mm or positive lymph node) were entered into this study. Three cycles of chemotherapy with 3,500 mg/m{sup 2} of 5-fluorouracil (5-FU) and nedaplatin (NDP) were accompanied with pelvic irradiation of 45.6-51.3 Gy in 24-27 fractions over 6 weeks. Prophylactic (36 Gy/20 fractions) or definitive (45-56 Gy) irradiation for para-aortic region was followed by pelvic irradiation. Results: Between 1998 and 2004, 40 patients were recruited for this protocol study. Eighteen patients from Phase I setting were registered. Twenty-two patients were treated with NDP of 140 mg/m{sup 2} (the recommended dose) in the Phase II segment. Twenty-five patients had T3 disease, and 25 patients had nodal disease including para-aortic involvement (n = 5). Overall/progression-free survival rates at 5 years were 78.8 and 66.5%, respectively. The median follow-up time was 61.8 months (25.5-106.7). Hematologic and gastrointestinal Grade 3 or more toxicities were relatively high rate (27.5-45%); however, they were well manageable. Two for bladder toxicity of Grade 3 were noted. Comparing the data from historical control group evaluated by magnetic resonance imaging, alternating chemoradiotherapy revealed a significant favorable factor for survival and disease recurrence in multivariate analysis (p < 0.05). Conclusion: Acquired results from our unique protocol for cervical cancer with high-risk factor were thought to be promising, considering that the majority of our cohort consisted of high-risk population.

  8. Preliminary Toxicity Analysis of 3-Dimensional Conformal Radiation Therapy Versus Intensity Modulated Radiation Therapy on the High-Dose Arm of the Radiation Therapy Oncology Group 0126 Prostate Cancer Trial

    SciTech Connect

    Michalski, Jeff M.; Yan, Yan; Watkins-Bruner, Deborah; Bosch, Walter R.; Winter, Kathryn; Galvin, James M.; Bahary, Jean-Paul; Morton, Gerard C.; Parliament, Matthew B.; Sandler, Howard M.

    2013-12-01

    Purpose: To give a preliminary report of clinical and treatment factors associated with toxicity in men receiving high-dose radiation therapy (RT) on a phase 3 dose-escalation trial. Methods and Materials: The trial was initiated with 3-dimensional conformal RT (3D-CRT) and amended after 1 year to allow intensity modulated RT (IMRT). Patients treated with 3D-CRT received 55.8 Gy to a planning target volume that included the prostate and seminal vesicles, then 23.4 Gy to prostate only. The IMRT patients were treated to the prostate and proximal seminal vesicles to 79.2 Gy. Common Toxicity Criteria, version 2.0, and Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer late morbidity scores were used for acute and late effects. Results: Of 763 patients randomized to the 79.2-Gy arm of Radiation Therapy Oncology Group 0126 protocol, 748 were eligible and evaluable: 491 and 257 were treated with 3D-CRT and IMRT, respectively. For both bladder and rectum, the volumes receiving 65, 70, and 75 Gy were significantly lower with IMRT (all P<.0001). For grade (G) 2+ acute gastrointestinal/genitourinary (GI/GU) toxicity, both univariate and multivariate analyses showed a statistically significant decrease in G2+ acute collective GI/GU toxicity for IMRT. There were no significant differences with 3D-CRT or IMRT for acute or late G2+ or 3+ GU toxicities. Univariate analysis showed a statistically significant decrease in late G2+ GI toxicity for IMRT (P=.039). On multivariate analysis, IMRT showed a 26% reduction in G2+ late GI toxicity (P=.099). Acute G2+ toxicity was associated with late G3+ toxicity (P=.005). With dose–volume histogram data in the multivariate analysis, RT modality was not significant, whereas white race (P=.001) and rectal V70 ≥15% were associated with G2+ rectal toxicity (P=.034). Conclusions: Intensity modulated RT is associated with a significant reduction in acute G2+ GI/GU toxicity. There is a trend for a

  9. EC declaration of conformity.

    PubMed

    Donawa, M E

    1996-05-01

    The CE-marking procedure requires that manufacturers draw up a written declaration of conformity before placing their products on the market. However, some companies do not realize that this is a requirement for all devices. Also, there is no detailed information concerning the contents and format of the EC declaration of conformity in the medical device Directives or in EC guidance documentation. This article will discuss some important aspects of the EC declaration of conformity and some of the guidance that is available on its contents and format.

  10. Animal culture: chimpanzee conformity?

    PubMed

    van Schaik, Carel P

    2012-05-22

    Culture-like phenomena in wild animals have received much attention, but how good is the evidence and how similar are they to human culture? New data on chimpanzees suggest their culture may even have an element of conformity.

  11. New potentials for conformal mechanics

    NASA Astrophysics Data System (ADS)

    Papadopoulos, G.

    2013-04-01

    We find under some mild assumptions that the most general potential of one-dimensional conformal systems with time-independent couplings is expressed as V = V0 + V1, where V0 is a homogeneous function with respect to a homothetic motion in configuration space and V1 is determined from an equation with source a homothetic potential. Such systems admit at most an SL(2,{R}) conformal symmetry which, depending on the couplings, is embedded in {Diff}({R}) in three different ways. In one case, SL(2,{R}) is also embedded in Diff(S1). Examples of such models include those with potential V = αx2 + βx-2 for arbitrary couplings α and β, the Calogero models with harmonic oscillator couplings and nonlinear models with suitable metrics and potentials. In addition, we give the conditions on the couplings for a class of gauge theories to admit a SL(2,{R}) conformal symmetry. We present examples of such systems with general gauge groups and global symmetries that include the isometries of AdS2 × S3 and AdS2 × S3 × S3 which arise as backgrounds in AdS2/CFT1.

  12. Conformable apparatus in a drill string

    DOEpatents

    Hall, David R.; Hall, Jr., H. Tracy; Pixton, David S.; Fox, Joe

    2007-08-28

    An apparatus in a drill string comprises an internally upset drill pipe. The drill pipe comprises a first end, a second end, and an elongate tube intermediate the first and second ends. The elongate tube and the ends comprising a continuous an inside surface with a plurality of diameters. A conformable metal tube is disposed within the drill pipe intermediate the ends thereof and terminating adjacent to the ends of the drill pipe. The conformable metal tube substantially conforms to the continuous inside surface of the metal tube. The metal tube may comprise a non-uniform section which is expanded to conform to the inside surface of the drill pipe. The non-uniform section may comprise protrusions selected from the group consisting of convolutions, corrugations, flutes, and dimples. The non-uniform section extends generally longitudinally along the length of the tube. The metal tube may be adapted to stretch as the drill pipes stretch.

  13. Conformational kinetics reveals affinities of protein conformational states.

    PubMed

    Daniels, Kyle G; Suo, Yang; Oas, Terrence G

    2015-07-28

    Most biological reactions rely on interplay between binding and changes in both macromolecular structure and dynamics. Practical understanding of this interplay requires detection of critical intermediates and determination of their binding and conformational characteristics. However, many of these species are only transiently present and they have often been overlooked in mechanistic studies of reactions that couple binding to conformational change. We monitored the kinetics of ligand-induced conformational changes in a small protein using six different ligands. We analyzed the kinetic data to simultaneously determine both binding affinities for the conformational states and the rate constants of conformational change. The approach we used is sufficiently robust to determine the affinities of three conformational states and detect even modest differences in the protein's affinities for relatively similar ligands. Ligand binding favors higher-affinity conformational states by increasing forward conformational rate constants and/or decreasing reverse conformational rate constants. The amounts by which forward rate constants increase and reverse rate constants decrease are proportional to the ratio of affinities of the conformational states. We also show that both the affinity ratio and another parameter, which quantifies the changes in conformational rate constants upon ligand binding, are strong determinants of the mechanism (conformational selection and/or induced fit) of molecular recognition. Our results highlight the utility of analyzing the kinetics of conformational changes to determine affinities that cannot be determined from equilibrium experiments. Most importantly, they demonstrate an inextricable link between conformational dynamics and the binding affinities of conformational states.

  14. Conformers of Gaseous Serine.

    PubMed

    He, Kedan; Allen, Wesley D

    2016-08-09

    The myriad conformers of the neutral form of natural amino acid serine (Ser) have been investigated by systematic computations with reliable electronic wave function methods. A total of 85 unique conformers were located using the MP2/cc-pVTZ level of theory. The 12 lowest-energy conformers of serine fall within a 8 kJ mol(-1) window, and for these species, geometric structures, precise relative energies, equilibrium and vibrationally averaged rotational constants, anharmonic vibrational frequencies, infrared intensities, quartic and sextic centrifugal distortion constants, dipole moments, and (14)N nuclear quadrupole coupling constants were computed. The relative energies were refined through composite focal-point analyses employing basis sets as large as aug-cc-pV5Z and correlation treatments through CCSD(T). The rotational constants for seven conformers measured by Fourier-transform microwave spectroscopy are in good agreement with the vibrationally averaged rotational constants computed in this study. Our anharmonic vibrational frequencies are compared to the large number of experimental vibrational absorptions attributable to at least six conformers.

  15. Charged conformal Killing spinors

    SciTech Connect

    Lischewski, Andree

    2015-01-15

    We study the twistor equation on pseudo-Riemannian Spin{sup c}-manifolds whose solutions we call charged conformal Killing spinors (CCKSs). We derive several integrability conditions for the existence of CCKS and study their relations to spinor bilinears. A construction principle for Lorentzian manifolds admitting CCKS with nontrivial charge starting from CR-geometry is presented. We obtain a partial classification result in the Lorentzian case under the additional assumption that the associated Dirac current is normal conformal and complete the classification of manifolds admitting CCKS in all dimensions and signatures ≤5 which has recently been initiated in the study of supersymmetric field theories on curved space.

  16. Infrared modification of gravity from conformal symmetry

    NASA Astrophysics Data System (ADS)

    Gegenberg, Jack; Rahmati, Shohreh; Seahra, Sanjeev S.

    2016-03-01

    We reconsider a gauge theory of gravity in which the gauge group is the conformal group SO(4,2), and the action is of the Yang-Mills form, quadratic in the curvature. The resulting gravitational theory exhibits local conformal symmetry and reduces to Weyl-squared gravity under certain conditions. When the theory is linearized about flat spacetime, we find that matter which couples to the generators of special conformal transformations reproduces Newton's inverse square law. Conversely, matter which couples to generators of translations induces a constant and possibly repulsive force far from the source, which may be relevant for explaining the late-time acceleration of the Universe. The coupling constant of the theory is dimensionless, which means that it is potentially renormalizable.

  17. Group typicality, group loyalty and cognitive development.

    PubMed

    Patterson, Meagan M

    2014-09-01

    Over the course of childhood, children's thinking about social groups changes in a variety of ways. Developmental Subjective Group Dynamics (DSGD) theory emphasizes children's understanding of the importance of conforming to group norms. Abrams et al.'s study, which uses DSGD theory as a framework, demonstrates the social cognitive skills underlying young elementary school children's thinking about group norms. Future research on children's thinking about groups and group norms should explore additional elements of this topic, including aspects of typicality beyond loyalty.

  18. Integrals of motion from TBA and lattice-conformal dictionary

    NASA Astrophysics Data System (ADS)

    Feverati, Giovanni; Grinza, Paolo

    2004-12-01

    The integrals of motion of the tricritical Ising model are obtained by thermodynamic Bethe ansatz (TBA) equations derived from the A integrable lattice model. They are compared with those given by the conformal field theory leading to a unique one-to-one lattice-conformal correspondence. They can also be followed along the renormalization group flows generated by the action of the boundary field φ on conformal boundary conditions in close analogy to the usual TBA description of energies.

  19. Logarithmic conformal field theory

    NASA Astrophysics Data System (ADS)

    Gainutdinov, Azat; Ridout, David; Runkel, Ingo

    2013-12-01

    Conformal field theory (CFT) has proven to be one of the richest and deepest subjects of modern theoretical and mathematical physics research, especially as regards statistical mechanics and string theory. It has also stimulated an enormous amount of activity in mathematics, shaping and building bridges between seemingly disparate fields through the study of vertex operator algebras, a (partial) axiomatisation of a chiral CFT. One can add to this that the successes of CFT, particularly when applied to statistical lattice models, have also served as an inspiration for mathematicians to develop entirely new fields: the Schramm-Loewner evolution and Smirnov's discrete complex analysis being notable examples. When the energy operator fails to be diagonalisable on the quantum state space, the CFT is said to be logarithmic. Consequently, a logarithmic CFT is one whose quantum space of states is constructed from a collection of representations which includes reducible but indecomposable ones. This qualifier arises because of the consequence that certain correlation functions will possess logarithmic singularities, something that contrasts with the familiar case of power law singularities. While such logarithmic singularities and reducible representations were noted by Rozansky and Saleur in their study of the U (1|1) Wess-Zumino-Witten model in 1992, the link between the non-diagonalisability of the energy operator and logarithmic singularities in correlators is usually ascribed to Gurarie's 1993 article (his paper also contains the first usage of the term 'logarithmic conformal field theory'). The class of CFTs that were under control at this time was quite small. In particular, an enormous amount of work from the statistical mechanics and string theory communities had produced a fairly detailed understanding of the (so-called) rational CFTs. However, physicists from both camps were well aware that applications from many diverse fields required significantly more

  20. Conformal cloak for waves

    SciTech Connect

    Chen Huanyang; Leonhardt, Ulf; Tyc, Tomas

    2011-05-15

    Conformal invisibility devices are only supposed to work within the valid range of geometrical optics. Here, we show by numerical simulations and analytical arguments that for certain quantized frequencies, they are nearly perfect even in a regime that clearly violates geometrical optics. The quantization condition follows from the analogy between the Helmholtz equation and the stationary Schroedinger equation.

  1. Evolution of Conformity in Social Dilemmas.

    PubMed

    Dong, Yali; Li, Cong; Tao, Yi; Zhang, Boyu

    2015-01-01

    People often deviate from their individual Nash equilibrium strategy in game experiments based on the prisoner's dilemma (PD) game and the public goods game (PGG), whereas conditional cooperation, or conformity, is supported by the data from these experiments. In a complicated environment with no obvious "dominant" strategy, conformists who choose the average strategy of the other players in their group could be able to avoid risk by guaranteeing their income will be close to the group average. In this paper, we study the repeated PD game and the repeated m-person PGG, where individuals' strategies are restricted to the set of conforming strategies. We define a conforming strategy by two parameters, initial action in the game and the influence of the other players' choices in the previous round. We are particularly interested in the tit-for-tat (TFT) strategy, which is the well-known conforming strategy in theoretical and empirical studies. In both the PD game and the PGG, TFT can prevent the invasion of non-cooperative strategy if the expected number of rounds exceeds a critical value. The stability analysis of adaptive dynamics shows that conformity in general promotes the evolution of cooperation, and that a regime of cooperation can be established in an AllD population through TFT-like strategies. These results provide insight into the emergence of cooperation in social dilemma games.

  2. Alkyl chlorido hydridotris(3,5-dimethylpyrazolyl)borate imido niobium and tantalum(V) complexes: synthesis, conformational states of alkyl groups in solid and solution, X-ray diffraction and multinuclear magnetic resonance spectroscopy studies.

    PubMed

    Galájov, Miguel; García, Carlos; Gómez, Manuel; Gómez-Sal, Pilar

    2014-04-21

    The alkylation of the starting pseudooctahedral dichlorido imido hydridotris(3,5-dimethylpyrazolyl)borate niobium and tantalum(v) compounds [MTp*Cl2(NtBu)] (M = Nb,Ta; Tp* = BH(3,5-Me2C3HN2)3) with MgClR in different conditions led to new alkyl chlorido imido derivatives [MTp*ClR(NtBu)] (M = Nb/Ta, R = CH2CH31a/1b, CH2Ph 2a/2b, CH2tBu 3a/3b, CH2SiMe34a/4b, CH2CMe2Ph 5a/5b), whereas the dimethyl derivatives [MTp*Me2(NtBu)] (M = Nb 6a, Ta 6b) could be isolated as unitary species when the reaction was carried out using 2 equivalents of the magnesium reagent MgClMe. However, the chlorido methyl [MTp*ClMe(NtBu)] (M = Nb 7a, Ta 7b) complexes were obtained by heating at 50 °C the dichlorido and dimethyl imido complexes mixtures in a 1 : 1 ratio. All of the complexes were studied by multinuclear magnetic resonance spectroscopy and the molecular structures of 1b, 2a/b, 3a/b, 4a and 5a/b were determined by X-ray diffraction methods. In the solid state the complexes 1b, 4a and 5a exhibit only a gauche-anti conformation and the complexes 2a/b, 3a/b and 5b exhibit only a gauche-syn conformation of the alkyl substituents, whereas both conformational states, which do not show mutual exchange in the NMR time scale, were observed for 3a/b in a benzene-d6 solution. The (15)N chemical shifts of the complexes 1-7 are discussed.

  3. Transportation Conformity Training and Presentations

    EPA Pesticide Factsheets

    EPA's OTAQ has provided multiple conformity training sessions in the past to assist state and local governments in implementing conformity requirements. As training information is prepared for other venues, it will be posted on this page.

  4. Conformation analysis of intermediates of analogues of Tamoxifen

    NASA Astrophysics Data System (ADS)

    Kapiller-Dezsőfi, Rita; Németh, Gábor; Lax, Györgyi; Simig, Gyula; Sohár, Pál

    1998-01-01

    The configuration and the conformation of two trifluoromethyl-triaryl-ethane diastereomer pairs and of some sole isomers were determined using the through-space spin-spin coupling between fluorine atoms and the hydrogen of the hydroxyl group. The molecule-mechanical calculations support the results of the conformation-analysis based on the NMR data.

  5. 42 CFR 411.112 - Documentation of conformance.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 2 2010-10-01 2010-10-01 false Documentation of conformance. 411.112 Section 411... Services Covered Under Group Health Plans: General Provisions § 411.112 Documentation of conformance. (a) Acceptable documentation. CMS may require a GHP or LGHP to demonstrate that it has complied with the...

  6. Multiscale conformal pattern transfer

    PubMed Central

    Lodewijks, Kristof; Miljkovic, Vladimir; Massiot, Inès; Mekonnen, Addis; Verre, Ruggero; Olsson, Eva; Dmitriev, Alexandre

    2016-01-01

    We demonstrate a method for seamless transfer from a parent flat substrate of basically any lithographic top-down or bottom-up pattern onto essentially any kind of surface. The nano- or microscale patterns, spanning macroscopic surface areas, can be transferred with high conformity onto a large variety of surfaces when such patterns are produced on a thin carbon film, grown on top of a sacrificial layer. The latter allows lifting the patterns from the flat parent substrate onto a water-air interface to be picked up by the host surface of choice. We illustrate the power of this technique by functionalizing broad range of materials including glass, plastics, metals, rough semiconductors and polymers, highlighting the potential applications in in situ colorimetry of the chemistry of materials, anti-counterfeit technologies, biomolecular and biomedical studies, light-matter interactions at the nanoscale, conformal photovoltaics and flexible electronics. PMID:27329824

  7. Multiscale conformal pattern transfer

    NASA Astrophysics Data System (ADS)

    Lodewijks, Kristof; Miljkovic, Vladimir; Massiot, Inès; Mekonnen, Addis; Verre, Ruggero; Olsson, Eva; Dmitriev, Alexandre

    2016-06-01

    We demonstrate a method for seamless transfer from a parent flat substrate of basically any lithographic top-down or bottom-up pattern onto essentially any kind of surface. The nano- or microscale patterns, spanning macroscopic surface areas, can be transferred with high conformity onto a large variety of surfaces when such patterns are produced on a thin carbon film, grown on top of a sacrificial layer. The latter allows lifting the patterns from the flat parent substrate onto a water-air interface to be picked up by the host surface of choice. We illustrate the power of this technique by functionalizing broad range of materials including glass, plastics, metals, rough semiconductors and polymers, highlighting the potential applications in in situ colorimetry of the chemistry of materials, anti-counterfeit technologies, biomolecular and biomedical studies, light-matter interactions at the nanoscale, conformal photovoltaics and flexible electronics.

  8. Conformational flexibility of aspartame.

    PubMed

    Toniolo, Claudio; Temussi, Pierandrea

    2016-05-01

    L-Aspartyl-L-phenylalanine methyl ester, better known as aspartame, is not only one of the most used artificial sweeteners, but also a very interesting molecule with respect to the correlation between molecular structure and taste. The extreme conformational flexibility of this dipeptide posed a huge difficulty when researchers tried to use it as a lead compound to design new sweeteners. In particular, it was difficult to take advantage of its molecular model as a mold to infer the shape of the, then unknown, active site of the sweet taste receptor. Here, we follow the story of the 3D structural aspects of aspartame from early conformational studies to recent docking into homology models of the receptor. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 376-384, 2016.

  9. Conformal ALON® windows

    NASA Astrophysics Data System (ADS)

    Goldman, Lee M.; Balasubramanian, Sreeram; Smith, Mark; Nag, Nagendra; Foti, Robyn; Jha, Santosh; Sastri, Suri

    2014-05-01

    Aluminum Oxynitride (ALON® Optical Ceramic) combines broadband transparency with excellent mechanical properties. ALON's cubic structure means that it is transparent in its polycrystalline form, allowing it to be manufactured by conventional powder processing techniques. Surmet controls every aspect of the manufacturing process, beginning with synthesis of ALON® powder, continuing through forming/heat treatment of blanks, ending with optical fabrication of ALON® windows. Surmet has made significant progress in its production capability in recent years. Additional scale up of Surmet's manufacturing capability, for complex geometries, larger sizes and higher quantities, is underway. The requirements for modern aircraft are driving the need for conformal windows for future sensor systems. However, limitations on optical systems and the ability to produce windows in complex geometries currently limit the geometry of existing windows and window assemblies to faceted assemblies of flat windows. Surmet's ability to produce large curved ALON® blanks is an important step in the development of conformal windows for future aircraft applications.

  10. Theoretical studies on the conformation of saccharides. XIV. Structure and conformational properties of the glycosylamines.

    PubMed

    Kozár, T; Tvaroska, I

    1990-01-01

    The 2-methylaminotetrahydropyran was used as a model to study conformational properties of the N-glycosidic linkage in glycosylamines. Relaxed two-dimensional conformational (phi, psi) maps in 20 solvents were calculated by a method in which the total energy is divided into the energy of the isolated molecule and the solvation energy. Molecular geometry optimization has been carried out for each conformer using the quantum chemical method PCILO. The calculated variations of the geometry are consistent with the results obtained by the statistical analysis of available experimental data retrieved from the Cambridge Structural Database. The calculated abundances of conformers show that the polarity of the solvent has little effect on the anomeric ratio, and the form having the methylamino group equatorial is favored in all considered solvents.

  11. Conformity to peer pressure in preschool children.

    PubMed

    Haun, Daniel B M; Tomasello, Michael

    2011-01-01

    Both adults and adolescents often conform their behavior and opinions to peer groups, even when they themselves know better. The current study investigated this phenomenon in 24 groups of 4 children between 4;2 and 4;9 years of age. Children often made their judgments conform to those of 3 peers, who had made obviously erroneous but unanimous public judgments right before them. A follow-up study with 18 groups of 4 children between 4;0 and 4;6 years of age revealed that children did not change their "real" judgment of the situation, but only their public expression of it. Preschool children are subject to peer pressure, indicating sensitivity to peers as a primary social reference group already during the preschool years.

  12. Conformal scalar field wormholes

    NASA Technical Reports Server (NTRS)

    Halliwell, Jonathan J.; Laflamme, Raymond

    1989-01-01

    The Euclidian Einstein equations with a cosmological constant and a conformally coupled scalar field are solved, taking the metric to be of the Robertson-Walker type. In the case Lambda = 0, solutions are found which represent a wormhole connecting two asymptotically flat Euclidian regions. In the case Lambda greater than 0, the solutions represent tunneling from a small Tolman-like universe to a large Robertson-Walker universe.

  13. The conformal bootstrap

    NASA Astrophysics Data System (ADS)

    Poland, David; Simmons-Duffin, David

    2016-06-01

    The conformal bootstrap was proposed in the 1970s as a strategy for calculating the properties of second-order phase transitions. After spectacular success elucidating two-dimensional systems, little progress was made on systems in higher dimensions until a recent renaissance beginning in 2008. We report on some of the main results and ideas from this renaissance, focusing on new determinations of critical exponents and correlation functions in the three-dimensional Ising and O(N) models.

  14. Conformal collineations and anisotropic fluids in general relativity

    NASA Astrophysics Data System (ADS)

    Duggal, K. L.; Sharma, R.

    1986-10-01

    Recently, Herrera et al. [L. Herrera, J. Jimenez, L. Leal, J. Ponce de Leon, M. Esculpi, and V. Galino, J. Math. Phys. 25, 3274 (1984)] studied the consequences of the existence of a one-parameter group of conformal motions for anisotropic matter. They concluded that for special conformal motions, the stiff equation of state (p=μ) is singled out in a unique way, provided the generating conformal vector field is orthogonal to the four-velocity. In this paper, the same problem is studied by using conformal collineations (which include conformal motions as subgroups). It is shown that, for a special conformal collineation, the stiff equation of state is not singled out. Non-Einstein Ricci-recurrent spaces are considered as physical models for the fluid matter.

  15. Network Visualization of Conformational Sampling during Molecular Dynamics Simulation

    PubMed Central

    Ahlstrom, Logan S.; Baker, Joseph Lee; Ehrlich, Kent; Campbell, Zachary T.; Patel, Sunita; Vorontsov, Ivan I.; Tama, Florence; Miyashita, Osamu

    2013-01-01

    Effective data reduction methods are necessary for uncovering the inherent conformational relationships present in large molecular dynamics (MD) trajectories. Clustering algorithms provide a means to interpret the conformational sampling of molecules during simulation by grouping trajectory snapshots into a few subgroups, or clusters, but the relationships between the individual clusters may not be readily understood. Here we show that network analysis can be used to visualize the dominant conformational states explored during simulation as well as the connectivity between them, providing a more coherent description of conformational space than traditional clustering techniques alone. We compare the results of network visualization against 11 clustering algorithms and principal component conformer plots. Several MD simulations of proteins undergoing different conformational changes demonstrate the effectiveness of networks in reaching functional conclusions. PMID:24211466

  16. Electrical control of protein conformation.

    PubMed

    Wan, Alwin M D; Schur, Rebecca M; Ober, Christopher K; Fischbach, Claudia; Gourdon, Delphine; Malliaras, George G

    2012-05-08

    Conducting polymer devices that enable precise control of fibronectin conformation over macroscopic areas are reported. Single conformations as well as conformation gradients are achieved by applying an appropriate potential. These surfaces remain biologically relevant and support cell culture; hence, they may serve as a model to understand and control cell-surface interactions, with applications in basic research, medical diagnostics, and tissue engineering.

  17. Seed conformal blocks in 4D CFT

    NASA Astrophysics Data System (ADS)

    Echeverri, Alejandro Castedo; Elkhidir, Emtinan; Karateev, Denis; Serone, Marco

    2016-02-01

    We compute in closed analytical form the minimal set of "seed" conformal blocks associated to the exchange of generic mixed symmetry spinor/tensor operators in an arbitrary representation ( ℓ, overline{ℓ} ) of the Lorentz group in four dimensional conformal field theories. These blocks arise from 4-point functions involving two scalars, one (0, | ℓ - overline{7ell;} |) and one (| ℓ - overline{ℓ} |, 0) spinors or tensors. We directly solve the set of Casimir equations, that can elegantly be written in a compact form for any ( ℓ, overline{ℓ} ), by using an educated ansatz and reducing the problem to an algebraic linear system. Various details on the form of the ansatz have been deduced by using the so called shadow formalism. The complexity of the conformal blocks depends on the value of p = | ℓ - overline{ℓ} | and grows with p, in analogy to what happens to scalar conformal blocks in d even space-time dimensions as d increases. These results open the way to bootstrap 4-point functions involving arbitrary spinor/tensor operators in four dimensional conformal field theories.

  18. Conformal Janus on Euclidean sphere

    NASA Astrophysics Data System (ADS)

    Bak, Dongsu; Gustavsson, Andreas; Rey, Soo-Jong

    2016-12-01

    We interpret Janus as an interface in a conformal field theory and study its properties. The Janus is created by an exactly marginal operator and we study its effect on the interface conformal field theory on the Janus. We do this by utilizing the AdS/CFT correspondence. We compute the interface free energy both from leading correction to the Euclidean action in the dual gravity description and from conformal perturbation theory in the conformal field theory. We find that the two results agree each other and that the interface free energy scales precisely as expected from the conformal invariance of the Janus interface.

  19. Conformal vectors and stellar models

    NASA Astrophysics Data System (ADS)

    Manjonjo, A. M.; Maharaj, S. D.; Moopanar, S.

    2017-02-01

    The relationship between conformal symmetries and relativistic spheres in astrophysics is studied. We use the nonvanishing components of the Weyl tensor to classify the conformal symmetries in static spherical spacetimes. It is possible to find an explicit connection between the two gravitational potentials for both conformally flat and nonconformally flat cases. We show that the conformal Killing vector admits time dependence in terms of quadratic, trigonometric and hyperbolic functions. The Einstein and Einstein-Maxwell field equations can be written in terms of a single potential, any choice of which leads to an exact solution. Previous results of conformally invariant static spheres are contained in our treatment.

  20. Conformation-activity relationships of opiate analgesics

    NASA Astrophysics Data System (ADS)

    Martin, Jennifer; Andrews, Peter

    1987-04-01

    Extensive conformational calculations were performed on the potent opiate analgesics etorphine, PET, R30490 and etonitazene to determine all of their many low-energy conformations. The results were used to characterize four possible models for binding of a simple pharmacophore, comprising two phenyl rings plus a protonated nitrogen, to opiate analgesic receptors. These four models may define the necessary three-dimensional features leading to particular opiate actions. The model favoured for μ receptor activity can accommodate a protonated nitrogen, an aromatic ring (which may be substituted with an electronegative group) and a second lipophilic group. These structural features must be presented in a precise three-dimensional arrangement. It appears likely that a hydrophilic substituent in a certain region of the analgesic pharmacophore may also interact with the receptor as a secondary binding group.

  1. OSI Conformance Testing for Bibliographic Applications.

    ERIC Educational Resources Information Center

    Arbez, Gilbert; Swain, Leigh

    1990-01-01

    Describes the development of Open Systems Interconnection (OSI) conformance testing sites, conformance testing tools, and conformance testing services. Discusses related topics such as interoperability testing, arbitration testing, and international harmonization of conformance testing. A glossary is included. (24 references) (SD)

  2. Tautomeric and conformational properties of dipivaloylmethane

    NASA Astrophysics Data System (ADS)

    Belova, Natalya V.; Trang, Nguen Hoang; Oberhammer, Heinz; Girichev, Georgiy V.

    2017-03-01

    The tautomeric and structural properties of 5-hydroxy-2,2,6,6-tetramethyl-3-heptanone, (dipivaloylmethane, C(CH3)3C(O)CH2C(O)C(CH3)3) have been studied by means of gas-phase electron diffraction (GED) and quantum chemical calculations (B3LYP and MP2 approximation with different basis sets up to aug-cc-pVTZ). Both, quantum chemistry and GED analyses resulted in the presence of 100(5)% enol tautomer at 296(3)K. Quantum chemical calculations predict the existence of two enol conformers in about equal amounts. In both conformers the enol ring possesses Cs symmetry and they possess different torsional orientations of the two tert-butyl groups. The experimental data refinement results in an enol tautomer, in which the tert-butyl group adjacent to the carbonyl group possesses an intermediate orientation between those in "enol1" and "enol 2" forms (torsional angle is about 30°), and the tert-butyl group adjacent to the hydroxyl group slightly deviates from orientation in the theoretical conformers (by about 10°). The enol ring possesses CS symmetry with a strongly asymmetric hydrogen bond. The experimental geometric parameters are reproduced very closely by the B3LYP/aug-cc-pVTZ method.

  3. Metamaterials with conformational nonlinearity

    PubMed Central

    Lapine, Mikhail; Shadrivov, Ilya V.; Powell, David A.; Kivshar, Yuri S.

    2011-01-01

    Within a decade of fruitful development, metamaterials became a prominent area of research, bridging theoretical and applied electrodynamics, electrical engineering and material science. Being man-made structures, metamaterials offer a particularly useful playground to develop interdisciplinary concepts. Here we demonstrate a novel principle in metamaterial assembly which integrates electromagnetic, mechanical, and thermal responses within their elements. Through these mechanisms, the conformation of the meta-molecules changes, providing a dual mechanism for nonlinearity and offering nonlinear chirality. Our proposal opens a wide road towards further developments of nonlinear metamaterials and photonic structures, adding extra flexibility to their design and control. PMID:22355655

  4. Leaf growth is conformal

    NASA Astrophysics Data System (ADS)

    Alim, Karen; Armon, Shahaf; Shraiman, Boris I.; Boudaoud, Arezki

    2016-10-01

    Growth pattern dynamics lie at the heart of morphogenesis. Here, we investigate the growth of plant leaves. We compute the conformal transformation that maps the contour of a leaf at a given stage onto the contour of the same leaf at a later stage. Based on the mapping we predict the local displacement field in the leaf blade and find it to agree with the experimentally measured displacement field to 92%. This approach is applicable to any two-dimensional system with locally isotropic growth, enabling the deduction of the whole growth field just from observation of the tissue contour.

  5. Conformal symmetry and the Balitsky-Kovchegov equation

    SciTech Connect

    Gubser, Steven S.

    2011-10-15

    Solutions to the Balitsky-Kovchegov equation are considered which respect an SO(3) subgroup of the conformal group. The symmetry dictates a specific dependence of the saturation scale on the impact parameter. Applications to deep inelastic scattering are considered.

  6. Discovering Conformational Sub-States Relevant to Protein Function

    PubMed Central

    Ramanathan, Arvind; Savol, Andrej J.; Langmead, Christopher J.; Agarwal, Pratul K.; Chennubhotla, Chakra S.

    2011-01-01

    Background Internal motions enable proteins to explore a range of conformations, even in the vicinity of native state. The role of conformational fluctuations in the designated function of a protein is widely debated. Emerging evidence suggests that sub-groups within the range of conformations (or sub-states) contain properties that may be functionally relevant. However, low populations in these sub-states and the transient nature of conformational transitions between these sub-states present significant challenges for their identification and characterization. Methods and Findings To overcome these challenges we have developed a new computational technique, quasi-anharmonic analysis (QAA). QAA utilizes higher-order statistics of protein motions to identify sub-states in the conformational landscape. Further, the focus on anharmonicity allows identification of conformational fluctuations that enable transitions between sub-states. QAA applied to equilibrium simulations of human ubiquitin and T4 lysozyme reveals functionally relevant sub-states and protein motions involved in molecular recognition. In combination with a reaction pathway sampling method, QAA characterizes conformational sub-states associated with cis/trans peptidyl-prolyl isomerization catalyzed by the enzyme cyclophilin A. In these three proteins, QAA allows identification of conformational sub-states, with critical structural and dynamical features relevant to protein function. Conclusions Overall, QAA provides a novel framework to intuitively understand the biophysical basis of conformational diversity and its relevance to protein function. PMID:21297978

  7. Molecular dynamics studies of the conformation of sorbitol

    PubMed Central

    Lerbret, A.; Mason, P.E.; Venable, R.M.; Cesàro, A.; Saboungi, M.-L.; Pastor, R.W.; Brady, J.W.

    2009-01-01

    Molecular dynamics simulations of a 3 m aqueous solution of D-sorbitol (also called D-glucitol) have been performed at 300 K, as well as at two elevated temperatures to promote conformational transitions. In principle, sorbitol is more flexible than glucose since it does not contain a constraining ring. However, a conformational analysis revealed that the sorbitol chain remains extended in solution, in contrast to the bent conformation found experimentally in the crystalline form. While there are 243 staggered conformations of the backbone possible for this open-chain polyol, only a very limited number were found to be stable in the simulations. Although many conformers were briefly sampled, only eight were significantly populated in the simulation. The carbon backbones of all but two of these eight conformers were completely extended, unlike the bent crystal conformation. These extended conformers were stabilized by a quite persistent intramolecular hydrogen bond between the hydroxyl groups of carbon C-2 and C-4. The conformational populations were found to be in good agreement with the limited available NMR data except for the C-2–C-3 torsion (spanned by the O-2–O-4 hydrogen bond), where the NMR data supports a more bent structure. PMID:19744646

  8. Conformational analysis of [Met5]-enkephalin: Solvation and ionization considerations

    NASA Astrophysics Data System (ADS)

    Carlacci, Louis

    1998-03-01

    [Met5]-Enkephalin has the sequence Tyr-Gly-Gly-Phe-Met. Only the extended conformation of the peptide has been observed by X-ray crystallography. Nuclear magnetic resonance spectroscopy supports the presence of a turn at Gly 3 and Phe 4 in dimethyl sulfoxide. In this study, the peptide conformational states and thermodynamic properties are understood in terms of ionization state and solvent environment. In the calculation, final conformations obtained from multiple independent Monte Carlo simulated annealing conformational searches are starting points for molecular dynamics simulations. In an aqueous environment given by the use of solvation free energy and the zwitterionic state, dominant structural motifs computed are G-P Type II' bend, G-G Type II' bend, and G-G Type I' bend motifs, in order of increasing free energy. In the calculation of the peptide with neutral N- and C-termini and solvation free energy, the extended conformer dominates (by at least a factor of 2.5), and the conformation of another low free energy conformer superimposes well on the pharmacophoric groups of morphine. Neutralization of charge and solvation induce and stabilize the extended conformation, respectively. A mechanism of inter-conversion between the extended conformer and three bent conformers is supported by φ/ψ-scatter plots, and by the conformer relative free energies. An estimate of the entropy change of receptor unbinding is 8.3 cal K-1 mol-1, which gives rise to a -2.5 kcal/mol entropy contribution to the free energy of unbinding at 25 °C. The conformational analysis methodology described here should be useful in studies on short peptides and flexible protein surface loops that have important biological implications.

  9. Eikonalization of conformal blocks

    SciTech Connect

    Fitzpatrick, A. Liam; Kaplan, Jared; Walters, Matthew T.; Wang, Junpu

    2015-09-03

    Classical field configurations such as the Coulomb potential and Schwarzschild solution are built from the t-channel exchange of many light degrees of freedom. We study the CFT analog of this phenomenon, which we term the 'eikonalization' of conformal blocks. We show that when an operator T appears in the OPE Ο(x)Ο(0), then the large spin Fock space states [TT···T] also appear in this OPE with a computable coefficient. The sum over the exchange of these Fock space states in an correlator build the classical 'T field' in the dual AdS description. In some limits the sum of all Fock space exchanges can be represented as the exponential of a single T exchange in the 4-pt correlator of O. Our results should be useful for systematizing 1/ℓ perturbation theory in general CFTs and simplifying the computation of large spin OPE coefficients. As examples we obtain the leading log ℓ dependence of Fock space conformal block coefficients, and we directly compute the OPE coefficients of the simplest ‘triple-trace’ operators.

  10. Eikonalization of conformal blocks

    DOE PAGES

    Fitzpatrick, A. Liam; Kaplan, Jared; Walters, Matthew T.; ...

    2015-09-03

    Classical field configurations such as the Coulomb potential and Schwarzschild solution are built from the t-channel exchange of many light degrees of freedom. We study the CFT analog of this phenomenon, which we term the 'eikonalization' of conformal blocks. We show that when an operator T appears in the OPE Ο(x)Ο(0), then the large spin Fock space states [TT···T]ℓ also appear in this OPE with a computable coefficient. The sum over the exchange of these Fock space states in an correlator build the classical 'T field' in the dual AdS description. In some limits the sum of all Fock spacemore » exchanges can be represented as the exponential of a single T exchange in the 4-pt correlator of O. Our results should be useful for systematizing 1/ℓ perturbation theory in general CFTs and simplifying the computation of large spin OPE coefficients. As examples we obtain the leading log ℓ dependence of Fock space conformal block coefficients, and we directly compute the OPE coefficients of the simplest ‘triple-trace’ operators.« less

  11. Conformally symmetric traversable wormholes

    SciTech Connect

    Boehmer, Christian G.; Harko, Tiberiu; Lobo, Francisco S. N.

    2007-10-15

    Exact solutions of traversable wormholes are found under the assumption of spherical symmetry and the existence of a nonstatic conformal symmetry, which presents a more systematic approach in searching for exact wormhole solutions. In this work, a wide variety of solutions are deduced by considering choices for the form function, a specific linear equation of state relating the energy density and the pressure anisotropy, and various phantom wormhole geometries are explored. A large class of solutions impose that the spatial distribution of the exotic matter is restricted to the throat neighborhood, with a cutoff of the stress-energy tensor at a finite junction interface, although asymptotically flat exact solutions are also found. Using the 'volume integral quantifier', it is found that the conformally symmetric phantom wormhole geometries may, in principle, be constructed by infinitesimally small amounts of averaged null energy condition violating matter. Considering the tidal acceleration traversability conditions for the phantom wormhole geometry, specific wormhole dimensions and the traversal velocity are also deduced.

  12. Quality of coverage: conformity measures for stereotactic radiosurgery.

    PubMed

    Wu, Q-R Jackie; Wessels, B W; Einstein, D B; Maciunas, R J; Kim, E Y; Kinsella, T J

    2003-01-01

    In radiosurgery, conformity indices are often used to compare competing plans, evaluate treatment techniques, and assess clinical complications. Several different indices have been reported to measure the conformity of the prescription isodose to the target volume. The PITV recommended in the Radiation Therapy Oncology Group (RTOG) radiosurgery guidelines, defined as the ratio of the prescription isodose volume (PI) over the target volume (TV), is probably the most frequently quoted. However, these currently used conformity indices depend on target size and shape complexity. The objectives of this study are to systematically investigate the influence of target size and shape complexity on existing conformity indices, and to propose a different conformity index-the conformity distance index (CDI). The CDI is defined as the average distance between the target and the prescription isodose line. This study examines five case groups with volumes of 0.3, 1.0, 3.0, 10.0, and 30.0 cm(3). Each case group includes four simulated shapes: a sphere, a moderate ellipsoid, an extreme ellipsoid, and a concave "C" shape. Prescription dose coverages are generated for three simplified clinical scenarios, i.e., the PI completely covers the TV with 1 and 2 mm margins, and the PI over-covers one half of the TV with a 1 mm margin and under-covers the other half with a 1 mm margin. Existing conformity indices and the CDI are calculated for these five case groups as well as seven clinical cases. When these values are compared, the RTOG PITV conformity index and other similar conformity measures have much higher values than the CDI for smaller and more complex shapes. With the same quality of prescription dose coverage, the CDI yields a consistent conformity measure. For the seven clinical cases, we also find that the same PITV values can be associated with very different conformity qualities while the CDI predicts the conformity quality accurately. In summary, the proposed CDI provides

  13. Recent Advances in Conformal Gravity

    NASA Astrophysics Data System (ADS)

    O'Brien, James; Chaykov, Spasen

    2016-03-01

    In recent years, significant advances have been made in alternative gravitational theories. Although MOND remains the leading candidate among the alternative models, Conformal Gravity has been studied by Mannheim and O'Brien to solve the rotation curve problem without the need for dark matter. Recently, Mannheim, O'Brien and Chaykov have begun solving other gravitational questions in Conformal Gravity. In this presentation, we highlight the new work of Conformal Gravity's application to random motions of clusters (the original Zwicky problem), gravitational bending of light, gravitational lensing and a very recent survey of dwarf galaxy rotation curves. We will show in each case that Conformal Gravity can provide an accurate explanation and prediction of the data without the need for dark matter. Coupled with the fact that Conformal Gravity is a fully re-normalizable metric theory of gravity, these results help to push Conformal Gravity onto a competitive stage against other alternative models.

  14. Fermion-scalar conformal blocks

    SciTech Connect

    Iliesiu, Luca; Kos, Filip; Poland, David; Pufu, Silviu S.; Simmons-Duffin, David; Yacoby, Ran

    2016-04-13

    In this study, we compute the conformal blocks associated with scalar-scalar-fermionfermion 4-point functions in 3D CFTs. Together with the known scalar conformal blocks, our result completes the task of determining the so-called ‘seed blocks’ in three dimensions. In addition, conformal blocks associated with 4-point functions of operators with arbitrary spins can now be determined from these seed blocks by using known differential operators.

  15. Conformal array antenna subsystem

    NASA Astrophysics Data System (ADS)

    1985-04-01

    An antenna subsystem to communicate between Ariane 4 and a data relay satellite was studied, concluding that the original ideas on ring antennas should be corrected due to the wide margin of coverage required in elevation for such antennas, which implies the need of splitting the coverage. Nevertheless, the study of cylindrical and conical conformal arrays was continued in view of their intrinsic interest. Needed coverages with specified gain can be obtained with a set of microstrip circular patch antennas. For the lower stage, a single patch is enough. For geostationary missions, one horizontal array is used, and for heliosynchronous missions two horizontal arrays and a vertical one. The numerical study carried out on omniazimuthal ring antennas shows that a tendency to omnidirectional pattern exists in spite of the directivity of the elementary radiators. A small pointing improvement of the meridian pattern can be obtained by means of conical arrays instead of the cylindrical ones.

  16. Capturing Chromosome Conformation

    NASA Astrophysics Data System (ADS)

    Dekker, Job; Rippe, Karsten; Dekker, Martijn; Kleckner, Nancy

    2002-02-01

    We describe an approach to detect the frequency of interaction between any two genomic loci. Generation of a matrix of interaction frequencies between sites on the same or different chromosomes reveals their relative spatial disposition and provides information about the physical properties of the chromatin fiber. This methodology can be applied to the spatial organization of entire genomes in organisms from bacteria to human. Using the yeast Saccharomyces cerevisiae, we could confirm known qualitative features of chromosome organization within the nucleus and dynamic changes in that organization during meiosis. We also analyzed yeast chromosome III at the G1 stage of the cell cycle. We found that chromatin is highly flexible throughout. Furthermore, functionally distinct AT- and GC-rich domains were found to exhibit different conformations, and a population-average 3D model of chromosome III could be determined. Chromosome III emerges as a contorted ring.

  17. Conformally symmetric relativistic star

    NASA Astrophysics Data System (ADS)

    Rahaman, Farook; Maharaj, Sunil D.; Sardar, Iftikar Hossain; Chakraborty, Koushik

    2017-03-01

    We investigate whether compact stars having Tolman-like interior geometry admit conformal symmetry. Taking anisotropic pressure along the two principal directions within the compact object, we obtain physically relevant quantities such as transverse and radial pressure, density and redshift function. We study the equation of state (EOS) for the matter distribution inside the star. From the relation between pressure and density function of the constituent matter, we explore the nature and properties of the interior matter. The redshift function and compactness parameter are found to be physically reasonable. The matter inside the star satisfies the null, weak and strong energy conditions. Finally, we compare the masses and radii predicted from the model with corresponding values in some observed stars.

  18. THE SEX VARIABLE IN CONFORMING BEHAVIOR.

    DTIC Science & Technology

    conformity to group influences has been attributed to cultural prescriptions for the female sex role. A battery of items was developed to isolate (a) item...The study calls into question the fact that, in most experimental studies, the tendency for females to be more susceptible to pressures toward...sophistication. Under these conditions, it was found that overall females yielded no more often than males to the pressures of an anonymous majority. More

  19. Replacement between conformity and counter-conformity in consumption decisions.

    PubMed

    Chou, Ting-Jui; Chang, En-Chung; Dai, Qi; Wong, Veronica

    2013-02-01

    This study assessed, in a Chinese context, how self-esteem interacts with perceived similarity and uniqueness to yield cognitive dissonance, and whether the dissonance leads to self-reported conformity or counter-conformity behavior. Participants were 408 respondents from 4 major Chinese cities (M age = 33.0 yr., SD = 4.3; 48% men). Self-perceptions of uniqueness, similarity, cognitive dissonance, self-esteem and need to behave in conformity or counter-conformity were measured. A theoretical model was assessed in four situations, relating the ratings of self-esteem and perceived similarity/uniqueness to the way other people at a wedding were dressed, and the resultant cognitive dissonance and conformity/ counter-conformity behavior. Regardless of high or low self-esteem, all participants reported cognitive dissonance when they were told that they were dressed extremely similarly to or extremely differently from the other people attending the wedding. However, the conforming/counter-conforming strategies used by participants to resolve the cognitive dissonance differed. When encountering dissonance induced by the perceived extreme uniqueness of dress, participants with low self-esteem tended to say they would dress next time so as to conform with the way others were dressed, while those with high self-esteem indicated they would continue their counter-conformity in attire. When encountering dissonance induced by the perceived extreme similarity to others, both those with high and low self-esteem tended to say they would dress in an unorthodox manner to surprise other people in the future.

  20. Counselor Identity: Conformity or Distinction?

    ERIC Educational Resources Information Center

    McLaughlin, Jerry E.; Boettcher, Kathryn

    2009-01-01

    The authors explore 3 debates in other disciplines similar to counseling's identity debate in order to learn about common themes and outcomes. Conformity, distinction, and cohesion emerged as common themes. They conclude that counselors should retain their distinctive, humanistic approach rather than conforming to the dominant, medical approach.

  1. Explicit mentalizing mechanisms and their adaptive role in memory conformity.

    PubMed

    Wheeler, Rebecca; Allan, Kevin; Tsivilis, Dimitris; Martin, Douglas; Gabbert, Fiona

    2013-01-01

    Memory conformity occurs when an individual endorses what other individuals remember about past events. Research on memory conformity is currently dominated by a 'forensic' perspective, which views the phenomenon as inherently undesirable. This is because conformity not only distorts the accuracy of an individual's memory, but also produces false corroboration between individuals, effects that act to undermine criminal justice systems. There is growing awareness, however, that memory conformity may be interpreted more generally as an adaptive social behavior regulated by explicit mentalizing mechanisms. Here, we provide novel evidence in support of this emerging alternative theoretical perspective. We carried out a memory conformity experiment which revealed that explicit belief-simulation (i.e. using one's own beliefs to model what other people believe) systematically biases conformity towards like-minded individuals, even when there is no objective evidence that they have a more accurate memory than dissimilar individuals. We suggest that this bias is functional, i.e. adaptive, to the extent that it fosters trust, and hence cooperation, between in-group versus out-group individuals. We conclude that memory conformity is, in more fundamental terms, a highly desirable product of explicit mentalizing mechanisms that promote adaptive forms of social learning and cooperation.

  2. Dynamics of protein conformations

    NASA Astrophysics Data System (ADS)

    Stepanova, Maria

    2010-10-01

    A novel theoretical methodology is introduced to identify dynamic structural domains and analyze local flexibility in proteins. The methodology employs a multiscale approach combining identification of essential collective coordinates based on the covariance analysis of molecular dynamics trajectories, construction of the Mori projection operator with these essential coordinates, and analysis of the corresponding generalized Langevin equations [M.Stepanova, Phys.Rev.E 76(2007)051918]. Because the approach employs a rigorous theory, the outcomes are physically transparent: the dynamic domains are associated with regions of relative rigidity in the protein, whereas off-domain regions are relatively soft. This also allows scoring the flexibility in the macromolecule with atomic-level resolution [N.Blinov, M.Berjanskii, D.S.Wishart, and M.Stepanova, Biochemistry, 48(2009)1488]. The applications include the domain coarse-graining and characterization of conformational stability in protein G and prion proteins. The results are compared with published NMR experiments. Potential applications for structural biology, bioinformatics, and drug design are discussed.

  3. Imaging of conformational changes

    SciTech Connect

    Michl, Josef

    2016-03-13

    Control of intramolecular conformational change in a small number of molecules or even a single one by an application of an outside electric field defined by potentials on nearby metal or dielectric surfaces has potential applications in both 3-D and 2-D nanotechnology. Specifically, the synthesis, characterization, and understanding of designed solids with controlled built-in internal rotational motion of a dipole promises a new class of materials with intrinsic dielectric, ferroelectric, optical and optoelectronic properties not found in nature. Controlled rotational motion is of great interest due to its expected utility in phenomena as diverse as transport, current flow in molecular junctions, diffusion in microfluidic channels, and rotary motion in molecular machines. A direct time-resolved observation of the dynamics of motion on ps or ns time scale in a single molecule would be highly interesting but is also very difficult and has yet to be accomplished. Much can be learned from an easier but still challenging comparison of directly observed initial and final orientational states of a single molecule, which is the basis of this project. The project also impacts the understanding of surface-enhanced Raman spectroscopy (SERS) and single-molecule spectroscopic detection, as well as the synthesis of solid-state materials with tailored properties from designed precursors.

  4. Conformal Fermi Coordinates

    SciTech Connect

    Dai, Liang; Pajer, Enrico; Schmidt, Fabian E-mail: Enrico.pajer@gmail.com

    2015-11-01

    Fermi Normal Coordinates (FNC) are a useful frame for isolating the locally observable, physical effects of a long-wavelength spacetime perturbation. Their cosmological application, however, is hampered by the fact that they are only valid on scales much smaller than the horizon. We introduce a generalization that we call Conformal Fermi Coordinates (CFC). CFC preserve all the advantages of FNC, but in addition are valid outside the horizon. They allow us to calculate the coupling of long- and short-wavelength modes on all scales larger than the sound horizon of the cosmological fluid, starting from the epoch of inflation until today, by removing the complications of the second order Einstein equations to a large extent, and eliminating all gauge ambiguities. As an application, we present a calculation of the effect of long-wavelength tensor modes on small scale density fluctuations. We recover previous results, but clarify the physical content of the individual contributions in terms of locally measurable effects and ''projection'' terms.

  5. Remarks on Polyelectrolyte Conformation

    NASA Astrophysics Data System (ADS)

    de Gennes, P. G.; Pincus, P.; Velasco, R. M.; Brochard, F.

    Nous discutons des conformations de polymères linéaires chargés en faisant les hypothèses suivantes : a) la chaĬne sans charge est flexible, b) la force éctrostatique domine les interactions monomère-monomère c) il n'y a pas de sels. 1) Pour le cas dilué (chaĬne non enchevetrees) en corrigeant le calcul self-consistant fait récemment par Richmond [1a], on trouve une taille des polyions égale a = R ND, qui est une fonction linéaire de l'indice de polymérisation N. Ce rèsultat est en accord avec les prècèdents travaux de Hermans et Overbeek [1b], Kuhn, Kunzle et Katchalsky [1c]. 2) Il existe un domaine pour des concentrations très petites c (c** < c < c*) oò les interactions èlectrostatiques entre les polyions sont supèrieures aux ènergies thermiques, il semble donc possible que les polyions puissent former un rèseau pèriodique à trois dimensions. Nèanmoins, il semble difficile de mettre en èvidence un rèseau si diluè. 3) Jusqu'ici toutes les expériences avec les polyélectrolytes sans sels ont été pratiquement faites à des concentrations c > c*, pour lesquelles les différentes cha.nes sont enchevêtrées. Pour discuter ce régime on s.intéresse uniquement au cas où la charge par unité de longueur est près du (ou audessus du) seuil de condensation, donc il existe une seule longueur ξ(c) caractérisant les corrélations; à trois dimensions 03BE a le même comportement que le rayon de Debye pour les contre-ions. On a considéré quelques conformations possibles : a) un réseau hexagonal de batonnets; b) un réseau cubique de batonnets; c) une phase isotrope de cha.nes partiellement flexibles. Les différentes structures formées de batonnets semblent avoir la même énergie électrostatique. Ce fait suggère que la phase isotrope peut être la plus favorable. On analyse cette dernière phase en utilisant les mêmes méthodes qui se sont révélées efficaces pour les solutions des polymères neutres. Dans le modèle isotrope

  6. Plasma membrane localization of Solanum tuberosum remorin from group 1, homolog 3 is mediated by conformational changes in a novel C-terminal anchor and required for the restriction of potato virus X movement].

    PubMed

    Perraki, Artemis; Cacas, Jean-Luc; Crowet, Jean-Marc; Lins, Laurence; Castroviejo, Michel; German-Retana, Sylvie; Mongrand, Sébastien; Raffaele, Sylvain

    2012-10-01

    The formation of plasma membrane (PM) microdomains plays a crucial role in the regulation of membrane signaling and trafficking. Remorins are a plant-specific family of proteins organized in six phylogenetic groups, and Remorins of group 1 are among the few plant proteins known to specifically associate with membrane rafts. As such, they are valuable to understand the molecular bases for PM lateral organization in plants. However, little is known about the structural determinants underlying the specific association of group 1 Remorins with membrane rafts. We used a structure-function approach to identify a short C-terminal anchor (RemCA) indispensable and sufficient for tight direct binding of potato (Solanum tuberosum) REMORIN 1.3 (StREM1.3) to the PM. RemCA switches from unordered to α-helical structure in a nonpolar environment. Protein structure modeling indicates that RemCA folds into a tight hairpin of amphipathic helices. Consistently, mutations reducing RemCA amphipathy abolished StREM1.3 PM localization. Furthermore, RemCA directly binds to biological membranes in vitro, shows higher affinity for Detergent-Insoluble Membranes lipids, and targets yellow fluorescent protein to Detergent-Insoluble Membranes in vivo. Mutations in RemCA resulting in cytoplasmic StREM1.3 localization abolish StREM1.3 function in restricting potato virus X movement. The mechanisms described here provide new insights on the control and function of lateral segregation of plant PM.

  7. Plasma Membrane Localization of Solanum tuberosum Remorin from Group 1, Homolog 3 Is Mediated by Conformational Changes in a Novel C-Terminal Anchor and Required for the Restriction of Potato Virus X Movement1[C][W

    PubMed Central

    Perraki, Artemis; Cacas, Jean-Luc; Crowet, Jean-Marc; Lins, Laurence; Castroviejo, Michel; German-Retana, Sylvie; Mongrand, Sébastien; Raffaele, Sylvain

    2012-01-01

    The formation of plasma membrane (PM) microdomains plays a crucial role in the regulation of membrane signaling and trafficking. Remorins are a plant-specific family of proteins organized in six phylogenetic groups, and Remorins of group 1 are among the few plant proteins known to specifically associate with membrane rafts. As such, they are valuable to understand the molecular bases for PM lateral organization in plants. However, little is known about the structural determinants underlying the specific association of group 1 Remorins with membrane rafts. We used a structure-function approach to identify a short C-terminal anchor (RemCA) indispensable and sufficient for tight direct binding of potato (Solanum tuberosum) REMORIN 1.3 (StREM1.3) to the PM. RemCA switches from unordered to α-helical structure in a nonpolar environment. Protein structure modeling indicates that RemCA folds into a tight hairpin of amphipathic helices. Consistently, mutations reducing RemCA amphipathy abolished StREM1.3 PM localization. Furthermore, RemCA directly binds to biological membranes in vitro, shows higher affinity for Detergent-Insoluble Membranes lipids, and targets yellow fluorescent protein to Detergent-Insoluble Membranes in vivo. Mutations in RemCA resulting in cytoplasmic StREM1.3 localization abolish StREM1.3 function in restricting potato virus X movement. The mechanisms described here provide new insights on the control and function of lateral segregation of plant PM. PMID:22855937

  8. Conformal symmetry and light flavor baryon spectra

    NASA Astrophysics Data System (ADS)

    Kirchbach, M.; Compean, C. B.

    2010-08-01

    The degeneracy among parity pairs systematically observed in the N and Δ spectra is interpreted to hint on a possible conformal symmetry realization in the light flavor baryon sector in line with AdS5/CFT4. The case is made by showing that all the observed N and Δ resonances with masses below 2500 MeV distribute fairly well each over the first levels of a unitary representation of the conformal group, a representation that covers the spectrum of a quark-diquark system, placed directly on a conformally compactified Minkowski spacetime, R1⊗S3, as approached from the AdS5 cone. The free geodesic motion on the S3 manifold is described by means of the scalar conformal equation there, which is of the Klein-Gordon-type. The equation is then gauged by the curved Coulomb potential that has the form of a cotangent function. Conformal symmetry is not exact, this because the gauge potential slightly modifies the conformal centrifugal barrier of the free geodesic motion. Thanks to this, the degeneracy between P11-S11 pairs from same level is relaxed, while the remaining states belonging to same level remain practically degenerate. The model describes the correct mass ordering in the P11-S11 pairs through the spectra as a combined effect of the above conformal symmetry breaking, on the one side, and a parity change of the diquark from a scalar at low masses, to a pseudoscalar at higher masses, on the other. The quality of the wave functions is illustrated by calculations of realistic mean square charge radii and electric charge form factors on the examples of the proton, and the protonic P11(1440), and S11(1535) resonances. The scheme also allows for a prediction of the dressing function of an effective instantaneous gluon propagator from the Fourier transform of the gauge potential. We find a dressing function that is finite in the infrared and tends to zero at infinity.

  9. De Sitter Transitivity, Conformal Transformations and Conservation Laws

    NASA Astrophysics Data System (ADS)

    Pereira, J. G.; Sampson, A. C.; Savi, L. L.

    2014-02-01

    Minkowski spacetime is transitive under ordinary translations, a transformation that do not have matrix representations. The de Sitter spacetime, on the other hand, is transitive under a combination of translations and proper conformal transformations, which do have a matrix representation. Such matrix, however, is not by itself a de Sitter generator: it gives rise to a conformal re-scaling of the metric, a transformation not belonging to the de Sitter group, and in general not associated with diffeomorphisms in spacetime. When dealing with variational principles and Noether's theorem in de Sitter spacetime, it is necessary to regularize the transformations in order to eliminate the conformal re-scaling of the metric.

  10. Seven Conformers of Pipecolic Acid Identified in the Gas Phase

    NASA Astrophysics Data System (ADS)

    Cabezas, Carlos; Simao, Alcides; Alonso, José L.

    2016-06-01

    The multiconformational landscape of the non-proteinogenic cyclic amino acid pipecolic acid has been explored in the gas phase. Solid pipecolic acid (m.p. 280°C) was vaporized by laser ablation (LA) and expanded in a supersonic jet where the rotational spectra of seven conformers were obtained by broadband microwave spectroscopy (CP-FTMW). All conformers were conclusively identified by comparison of the experimental spectroscopic constants with those predicted theoretically. The relative stability of the conformers rests on a delicate balance of the different intramolecular hydrogen bonds established between the carboxylic and the amino groups.

  11. Downregulation of the posterior medial frontal cortex prevents social conformity.

    PubMed

    Klucharev, Vasily; Munneke, Moniek A M; Smidts, Ale; Fernández, Guillén

    2011-08-17

    We often change our behavior to conform to real or imagined group pressure. Social influence on our behavior has been extensively studied in social psychology, but its neural mechanisms have remained largely unknown. Here we demonstrate that the transient downregulation of the posterior medial frontal cortex by theta-burst transcranial magnetic stimulation reduces conformity, as indicated by reduced conformal adjustments in line with group opinion. Both the extent and probability of conformal behavioral adjustments decreased significantly relative to a sham and a control stimulation over another brain area. The posterior part of the medial frontal cortex has previously been implicated in behavioral and attitudinal adjustments. Here, we provide the first interventional evidence of its critical role in social influence on human behavior.

  12. Prosocial Conformity: Prosocial Norms Generalize Across Behavior and Empathy.

    PubMed

    Nook, Erik C; Ong, Desmond C; Morelli, Sylvia A; Mitchell, Jason P; Zaki, Jamil

    2016-08-01

    Generosity is contagious: People imitate others' prosocial behaviors. However, research on such prosocial conformity focuses on cases in which people merely reproduce others' positive actions. Hence, we know little about the breadth of prosocial conformity. Can prosocial conformity cross behavior types or even jump from behavior to affect? Five studies address these questions. In Studies 1 to 3, participants decided how much to donate to charities before learning that others donated generously or stingily. Participants who observed generous donations donated more than those who observed stingy donations (Studies 1 and 2). Crucially, this generalized across behaviors: Participants who observed generous donations later wrote more supportive notes to another participant (Study 3). In Studies 4 and 5, participants observed empathic or non-empathic group responses to vignettes. Group empathy ratings not only shifted participants' own empathic feelings (Study 4), but they also influenced participants' donations to a homeless shelter (Study 5). These findings reveal the remarkable breadth of prosocial conformity.

  13. Differential invariants of self-dual conformal structures

    NASA Astrophysics Data System (ADS)

    Kruglikov, Boris; Schneider, Eivind

    2017-03-01

    We compute the quotient of the self-duality equation for conformal metrics by the action of the diffeomorphism group. We also determine Hilbert polynomial, counting the number of independent scalar differential invariants depending on the jet-order, and the corresponding Poincaré function. We describe the field of rational differential invariants separating generic orbits of the diffeomorphism pseudogroup action, resolving the local recognition problem for self-dual conformal structures.

  14. [Conformation of aspartate aminotransferase in crystals].

    PubMed

    Borisov, V V; Borisova, S N; Sosfenov, N I; Dikson, Kh BF

    1983-01-01

    X-ray study of chicken cytosolic aspartate aminotransferase revealed conformational changes in the protein of two kinds: (1) a shift of the small domain adjacent to substrate-binding area due to interaction of the protein with two carboxyl groups of substrate and (2) a change in inclination of the coenzyme plane due to replacement of C = N bond of the coenzyme with Lys-258 by C = N bond with a substrate. An asymmetry in subunit behaviour is observed in both cases: the domain is shifted in one subunit and the coenzyme is rotated in other. Substrate-binding properties of each subunit are strictly dependent on the protein conformation in substrate-binding area.

  15. Conformation-dependent DNA attraction

    NASA Astrophysics Data System (ADS)

    Li, Weifeng; Nordenskiöld, Lars; Zhou, Ruhong; Mu, Yuguang

    2014-05-01

    Understanding how DNA molecules interact with other biomolecules is related to how they utilize their functions and is therefore critical for understanding their structure-function relationships. For a long time, the existence of Z-form DNA (a left-handed double helical version of DNA, instead of the common right-handed B-form) has puzzled the scientists, and the definitive biological significance of Z-DNA has not yet been clarified. In this study, the effects of DNA conformation in DNA-DNA interactions are explored by molecular dynamics simulations. Using umbrella sampling, we find that for both B- and Z-form DNA, surrounding Mg2+ ions always exert themselves to screen the Coulomb repulsion between DNA phosphates, resulting in very weak attractive force. On the contrary, a tight and stable bound state is discovered for Z-DNA in the presence of Mg2+ or Na+, benefiting from their hydrophobic nature. Based on the contact surface and a dewetting process analysis, a two-stage binding process of Z-DNA is outlined: two Z-DNA first attract each other through charge screening and Mg2+ bridges to phosphate groups in the same way as that of B-DNA, after which hydrophobic contacts of the deoxyribose groups are formed via a dewetting effect, resulting in stable attraction between two Z-DNA molecules. The highlighted hydrophobic nature of Z-DNA interaction from the current study may help to understand the biological functions of Z-DNA in gene transcription.Understanding how DNA molecules interact with other biomolecules is related to how they utilize their functions and is therefore critical for understanding their structure-function relationships. For a long time, the existence of Z-form DNA (a left-handed double helical version of DNA, instead of the common right-handed B-form) has puzzled the scientists, and the definitive biological significance of Z-DNA has not yet been clarified. In this study, the effects of DNA conformation in DNA-DNA interactions are explored by

  16. CONFORMANCE IMPROVEMENT USING GELS

    SciTech Connect

    Randall S. Seright

    2002-02-28

    This technical progress report describes work performed from June 20 through December 19, 2001, for the project, ''Conformance Improvement Using Gels''. Interest has increased in some new polymeric products that purport to substantially reduce permeability to water while causing minimum permeability reduction to oil. In view of this interest, we are currently studying BJ's Aqua Con. Results from six corefloods revealed that the Aqua Con gelant consistently reduced permeability to water more than that to oil. However, the magnitude of the disproportionate permeability reduction varied significantly for the various experiments. Thus, as with most materials tested to date, the issue of reproducibility and control of the disproportionate permeability remains to be resolved. Concern exists about the ability of gels to resist washout after placement in fractures. We examined whether a width constriction in the middle of a fracture would cause different gel washout behavior upstream versus downstream of the constriction. Tests were performed using a formed Cr(III)-acetate-HPAM gel in a 48-in.-long fracture with three sections of equal length, but with widths of 0.08-, 0.02-, and 0.08-in., respectively. The pressure gradients during gel extrusion (i.e., placement) were similar in the two 0.08-in.-wide fracture sections, even though they were separated by a 0.02-in.-wide fracture section. The constriction associated with the middle fracture section may have inhibited gel washout during the first pulse of brine injection after gel placement. However, during subsequent phases of brine injection, the constriction did not inhibit washout in the upstream fracture section any more than in the downstream section.

  17. Predicting conformational switches in proteins.

    PubMed Central

    Young, M.; Kirshenbaum, K.; Dill, K. A.; Highsmith, S.

    1999-01-01

    We describe a new computational technique to predict conformationally switching elements in proteins from their amino acid sequences. The method, called ASP (Ambivalent Structure Predictor), analyzes results from a secondary structure prediction algorithm to identify regions of conformational ambivalence. ASP identifies ambivalent regions in 16 test protein sequences for which function involves substantial backbone rearrangements. In the test set, all sites previously described as conformational switches are correctly predicted to be structurally ambivalent regions. No such regions are predicted in three negative control protein sequences. ASP may be useful as a guide for experimental studies on protein function and motion in the absence of detailed three-dimensional structural data. PMID:10493576

  18. Conformational changes of adsorbed proteins

    NASA Astrophysics Data System (ADS)

    Allen, Scott

    2005-03-01

    The adsorption of bovine serum albumin (BSA) and pepsin to gold surfaces has been studied using surface plasmon resonance (SPR). Proteins are adsorbed from solution onto a gold surface and changes in the conformation of the adsorbed proteins are induced by changing the buffer solution. We selected pH and ionic strength values for the buffer solutions that are known from our circular dichroism measurements to cause conformational changes of the proteins in bulk solution. We find that for both BSA and pepsin the changes in conformation are impeded by the interaction of the protein with the gold surface.

  19. Conformal tensors via Lovelock gravity

    NASA Astrophysics Data System (ADS)

    Kastor, David

    2013-10-01

    Constructs from conformal geometry are important in low dimensional gravity models, while in higher dimensions the higher curvature interactions of Lovelock gravity are similarly prominent. Considering conformal invariance in the context of Lovelock gravity leads to natural, higher curvature generalizations of the Weyl, Schouten, Cotton and Bach tensors, with properties that straightforwardly extend those of their familiar counterparts. As a first application, we introduce a new set of conformally invariant gravity theories in D = 4k dimensions, based on the squares of the higher curvature Weyl tensors.

  20. The Principle of Maximum Conformality

    SciTech Connect

    Brodsky, Stanley J; Giustino, Di; /SLAC

    2011-04-05

    A key problem in making precise perturbative QCD predictions is the uncertainty in determining the renormalization scale of the running coupling {alpha}{sub s}({mu}{sup 2}). It is common practice to guess a physical scale {mu} = Q which is of order of a typical momentum transfer Q in the process, and then vary the scale over a range Q/2 and 2Q. This procedure is clearly problematic since the resulting fixed-order pQCD prediction will depend on the renormalization scheme, and it can even predict negative QCD cross sections at next-to-leading-order. Other heuristic methods to set the renormalization scale, such as the 'principle of minimal sensitivity', give unphysical results for jet physics, sum physics into the running coupling not associated with renormalization, and violate the transitivity property of the renormalization group. Such scale-setting methods also give incorrect results when applied to Abelian QED. Note that the factorization scale in QCD is introduced to match nonperturbative and perturbative aspects of the parton distributions in hadrons; it is present even in conformal theory and thus is a completely separate issue from renormalization scale setting. The PMC provides a consistent method for determining the renormalization scale in pQCD. The PMC scale-fixed prediction is independent of the choice of renormalization scheme, a key requirement of renormalization group invariance. The results avoid renormalon resummation and agree with QED scale-setting in the Abelian limit. The PMC global scale can be derived efficiently at NLO from basic properties of the PQCD cross section. The elimination of the renormalization scheme ambiguity using the PMC will not only increases the precision of QCD tests, but it will also increase the sensitivity of colliders to new physics beyond the Standard Model.

  1. Conformational Landscape of Nicotinoids: Solving the "conformational - Rity" of Anabasine

    NASA Astrophysics Data System (ADS)

    Lesarri, Alberto; Cocinero, Emilio J.; Evangelisti, Luca; Suenram, Richard D.; Caminati, Walther; Grabow, Jens-Uwe

    2010-06-01

    The conformational landscape of the alkaloid anabasine (neonicotine) has been investigated using rotational spectroscopy and ab initio calculations. The results allow a detailed comparison of the structural properties of the prototype piperidinic and pyrrolidinic nicotinoids (anabasine vs. nicotine). Anabasine adopts two most stable conformations in isolation conditions, for which we determined accurate rotational and nuclear quadrupole coupling parameters. The preferred conformations are characterized by an equatorial pyridine moiety and additional N-H equatorial stereochemistry at the piperidine ring (Eq-Eq). The two rings of anabasine are close to a bisecting arrangement, with the observed conformations differing in a ca. 180° rotation of the pyridine subunit, denoted either Syn or Anti. The preference of anabasine for the Eq-Eq-Syn conformation has been established by relative intensity measurements (Syn/Anti˜5(2)). The conformational preferences of free anabasine are directed by a N\\cdot\\cdot\\cdotH-C weak hydrogen bond interaction between the nitrogen lone pair at piperidine and the closest hydrogen bond in pyridine, with N\\cdot\\cdot\\cdotN distances ranging from 4.750 Å (Syn) to 4.233 Å (Anti). R. J. Lavrich, R. D. Suenram, D. F. Plusquellic and S. Davis, 58^th OSU Int. Symp. on Mol. Spectrosc., Columbus, OH, 2003, Comm. RH13.

  2. Conformity Adequacy Review: Region 5

    EPA Pesticide Factsheets

    Resources are for air quality and transportation government and community leaders. Information on the conformity SIP adequacy/inadequacy of state implementation plans (SIPs) in EPA Region 5 (IL, IN, MI, OH, WI) is provided here.

  3. Graphene-based conformal devices.

    PubMed

    Park, Yong Ju; Lee, Seoung-Ki; Kim, Min-Seok; Kim, Hyunmin; Ahn, Jong-Hyun

    2014-08-26

    Despite recent progress in bendable and stretchable thin-film transistors using novel designs and materials, the development of conformal devices remains limited by the insufficient flexibility of devices. Here, we demonstrate the fabrication of graphene-based conformal and stretchable devices such as transistor and tactile sensor on a substrate with a convoluted surface by scaling down the device thickness. The 70 nm thick graphene-based conformal devices displayed a much lower bending stiffness than reported previously. The demonstrated devices provided excellent conformal coverage over an uneven animal hide surface without the need for an adhesive. In addition, the ultrathin graphene devices formed on the three-dimensionally curved animal hide exhibited stable electrical characteristics, even under repetitive bending and twisting. The advanced performance and flexibility demonstrated here show promise for the development and adoption of wearable electronics in a wide range of future applications.

  4. Lattice Simulations and Infrared Conformality

    DOE PAGES

    Appelquist, Thomas; Fleming, George T.; Lin, Meifeng; ...

    2011-09-01

    We examine several recent lattice-simulation data sets, asking whether they are consistent with infrared conformality. We observe, in particular, that for an SU(3) gauge theory with 12 Dirac fermions in the fundamental representation, recent simulation data can be described assuming infrared conformality. Lattice simulations include a fermion mass m which is then extrapolated to zero, and we note that this data can be fit by a small-m expansion, allowing a controlled extrapolation. We also note that the conformal hypothesis does not work well for two theories that are known or expected to be confining and chirally broken, and that itmore » does work well for another theory expected to be infrared conformal.« less

  5. Conformal mapping of rectangular heptagons

    SciTech Connect

    Bogatyrev, Andrei B

    2012-12-31

    A new effective approach to calculating the direct and inverse conformal mapping of rectangular polygons onto a half-plane is put forward; it is based on the use of Riemann theta functions. Bibliography: 14 titles.

  6. Solution NMR conformation of glycosaminoglycans.

    PubMed

    Pomin, Vitor H

    2014-04-01

    Nuclear magnetic resonance (NMR) spectroscopy has been giving a pivotal contribution to the progress of glycomics, mostly by elucidating the structural, dynamical, conformational and intermolecular binding aspects of carbohydrates. Particularly in the field of conformation, NOE resonances, scalar couplings, residual dipolar couplings, and chemical shift anisotropy offsets have been the principal NMR parameters utilized. Molecular dynamics calculations restrained by NMR-data input are usually employed in conjunction to generate glycosidic bond dihedral angles. Glycosaminoglycans (GAGs) are a special class of sulfated polysaccharides extensively studied worldwide. Besides regulating innumerous physiological processes, these glycans are also widely explored in the global market as either clinical or nutraceutical agents. The conformational aspects of GAGs are key regulators to the quality of interactions with the functional proteins involved in biological events. This report discusses the solution conformation of each GAG type analyzed by one or more of the above-mentioned methods.

  7. CONFORMANCE IMPROVEMENT USING GELS

    SciTech Connect

    Randall S. Seright

    2004-09-30

    This report describes work performed during the third and final year of the project, ''Conformance Improvement Using Gels.'' Corefloods revealed throughput dependencies of permeability reduction by polymers and gels that were much more prolonged during oil flow than water flow. This behavior was explained using simple mobility ratio arguments. A model was developed that quantitatively fits the results and predicts ''clean up'' times for oil productivity when production wells are returned to service after application of a polymer or gel treatment. X-ray computed microtomography studies of gels in strongly water-wet Berea sandstone and strongly oil-wet porous polyethylene suggested that oil penetration through gel-filled pores occurs by a gel-dehydration mechanism, rather than gel-ripping or gel-displacement mechanisms. In contrast, analysis of data from the University of Kansas suggests that the gel-ripping or displacement mechanisms are more important in more permeable, strongly water-wet sandpacks. These findings help to explain why aqueous gels can reduce permeability to water more than to oil under different conditions. Since cement is the most commonly used material for water shutoff, we considered when gels are preferred over cements. Our analysis and experimental results indicated that cement cannot be expected to completely fill (top to bottom) a vertical fracture of any width, except near the wellbore. For vertical fractures with apertures less than 4 mm, the cement slurry will simply not penetrate very far into the fracture. For vertical fractures with apertures greater than 4 mm, the slurry may penetrate a substantial distance into the bottom part of the fracture. However, except near the wellbore, the upper part of the fracture will remain open due to gravity segregation. We compared various approaches to plugging fractures using gels, including (1) varying polymer content, (2) varying placement (extrusion) rate, (3) using partially formed gels, (4

  8. CONFORMANCE IMPROVEMENT USING GELS

    SciTech Connect

    Randall S. Seright

    2004-03-01

    This technical progress report describes work performed from September 1, 2003, through February 29, 2004, for the project, ''Conformance Improvement Using Gels.'' We examined the properties of several ''partially formed'' gels that were formulated with a combination of high and low molecular weight HPAM polymers. After placement in 4-mm-wide fractures, these gels required about 25 psi/ft for brine to breach the gel (the best performance to date in fractures this wide). After this breach, stabilized residual resistance factors decreased significantly with increased flow rate. Also, residual resistance factors were up to 9 times greater for water than for oil. Nevertheless, permeability reduction factors were substantial for both water and oil flow. Gel with 2.5% chopped fiberglass effectively plugged 4-mm-wide fractures if a 0.5-mm-wide constriction was present. The ability to screen-out at a constriction appears crucial for particulate incorporation to be useful in plugging fractures. In addition to fiberglass, we examined incorporation of polypropylene fibers into gels. Once dispersed in brine or gelant, the polypropylene fibers exhibited the least gravity segregation of any particulate that we have tested to date. In fractures with widths of at least 2 mm, 24-hr-old gels (0.5% high molecular weight HPAM) with 0.5% fiber did not exhibit progressive plugging during placement and showed extrusion pressure gradients similar to those of gels without the fiber. The presence of the fiber roughly doubled the gel's resistance to first breach by brine flow. The breaching pressure gradients were not as large as for gels made with high and low molecular weight polymers (mentioned above). However, their material requirements and costs (i.e., polymer and/or particulate concentrations) were substantially lower than for those gels. A partially formed gel made with 0.5% HPAM did not enter a 0.052-mm-wide fracture when applying a pressure gradient of 65 psi/ft. This result

  9. Patterns and conformations in molecularly thin films

    NASA Astrophysics Data System (ADS)

    Basnet, Prem B.

    Molecularly thin films have been a subject of great interest for the last several years because of their large variety of industrial applications ranging from micro-electronics to bio-medicine. Additionally, molecularly thin films can be used as good models for biomembrane and other systems where surfaces are critical. Many different kinds of molecules can make stable films. My research has considered three such molecules: a polymerizable phospholipid, a bent-core molecules, and a polymer. One common theme of these three molecules is chirality. The phospolipid molecules studied here are strongly chiral, which can be due to intrinsically chiral centers on the molecules and also due to chiral conformations. We find that these molecules give rise to chiral patterns. Bent-core molecules are not intrinsically chiral, but individual molecules and groups of molecules can show chiral structures, which can be changed by surface interactions. One major, unconfirmed hypothesis for the polymer conformation at surface is that it forms helices, which would be chiral. Most experiments were carried out at the air/water interface, in what are called Langmuir films. Our major tools for studying these films are Brewster Angle Microscopy (BAM) coupled with the thermodynamic information that can be deduced from surface pressure isotherms. Phospholipids are one of the important constituents of liposomes -- a spherical vesicle com-posed of a bilayer membrane, typically composed of a phospholipid and cholesterol bilayer. The application of liposomes in drug delivery is well-known. Crumpling of vesicles of polymerizable phospholipids has been observed. With BAM, on Langmuir films of such phospholipids, we see novel spiral/target patterns during compression. We have found that both the patterns and the critical pressure at which they formed depend on temperature (below the transition to a i¬‘uid layer). Bent-core liquid crystals, sometimes knows as banana liquid crystals, have drawn

  10. CONFORMANCE IMPROVEMENT USING GELS

    SciTech Connect

    Randall S. Seright

    2003-09-01

    This report describes work performed during the second year of the project, ''Conformance Improvement Using Gels.'' The project has two objectives. The first objective is to identify gel compositions and conditions that substantially reduce flow through fractures that allow direct channeling between wells, while leaving secondary fractures open so that high fluid injection and production rates can be maintained. The second objective is to optimize treatments in fractured production wells, where the gel must reduce permeability to water much more than that to oil. Pore-level images from X-ray computed microtomography were re-examined for Berea sandstone and porous polyethylene. This analysis suggests that oil penetration through gel-filled pores occurs by a gel-dehydration mechanism, rather than a gel-ripping mechanism. This finding helps to explain why aqueous gels can reduce permeability to water more than to oil. We analyzed a Cr(III)-acetate-HPAM gel treatment in a production well in the Arbuckle formation. The availability of accurate pressure data before, during, and after the treatment was critical for the analysis. After the gel treatment, water productivity was fairly constant at about 20% of the pre-treatment value. However, oil productivity was stimulated by a factor of 18 immediately after the treatment. During the six months after the treatment, oil productivity gradually decreased to approach the pre-treatment value. To explain this behavior, we proposed that the fracture area open to oil flow was increased substantially by the gel treatment, followed by a gradual closing of the fractures during subsequent production. For a conventional Cr(III)-acetate-HPAM gel, the delay between gelant preparation and injection into a fracture impacts the placement, leakoff, and permeability reduction behavior. Formulations placed as partially formed gels showed relatively low pressure gradients during placement, and yet substantially reduced the flow capacity of

  11. Generally covariant vs. gauge structure for conformal field theories

    SciTech Connect

    Campigotto, M.; Fatibene, L.

    2015-11-15

    We introduce the natural lift of spacetime diffeomorphisms for conformal gravity and discuss the physical equivalence between the natural and gauge natural structure of the theory. Accordingly, we argue that conformal transformations must be introduced as gauge transformations (affecting fields but not spacetime point) and then discuss special structures implied by the splitting of the conformal group. -- Highlights: •Both a natural and a gauge natural structure for conformal gravity are defined. •Global properties and natural lift of spacetime transformations are described. •The possible definitions of physical state are considered and discussed. •The gauge natural theory has less physical states than the corresponding natural one. •The dynamics forces to prefer the gauge natural structure over the natural one.

  12. Xanthan hydrogel films: molecular conformation, charge density and protein carriers.

    PubMed

    Bueno, Vânia Blasques; Petri, Denise Freitas Siqueira

    2014-01-30

    In this article the molecular conformation of xanthan chains in hydrogel films was investigated by means of circular dichroism, showing substantial differences between xanthan hydrogel prepared in the absence (XNT) and in the presence of citric acid (XCA). The xanthan chains in XNT hydrogels films presented ordered conformation (helixes), while in XCA they were in the disordered conformation (coils), exposing a larger number of carboxylate groups than XNT. The large charge density in XCA hydrogels was evidenced by their behavior under variable ionic strength. Studies about the application of XNT and XCA for loading and delivering of bovine serum albumin (BSA) and lysozyme (LYZ) showed that both events are controlled by hydrogels and proteins net charge, which can be triggered by pH. The preservation of LYZ native conformation after hydrogel loading explained the substantial bactericidal activity of LYZ loaded hydrogels and enables their use as active wound dressings.

  13. The Structure and Conformation of (CH3 )3 CSNO.

    PubMed

    Canneva, Antonela; Erben, Mauricio F; Romano, Rosana M; Vishnevskiy, Yury V; Reuter, Christian G; Mitzel, Norbert W; Della Védova, Carlos O

    2015-07-13

    The gas-phase molecular structure of (CH3 )3 CSNO was investigated by using electron diffraction, allowing the first experimental geometrical parameters for an S-nitrosothiol species to be elucidated. Depending on the orientation of the -SNO group, two conformers (anti and syn) are identified in the vapor of (CH3 )3 CSNO at room temperature, the syn conformer being less abundant. The conformational landscape is further scrutinized by using vibrational spectroscopy techniques, including gas-phase and matrix-isolation IR spectroscopy, resulting in a contribution of ca. 80:20 for the anti:syn abundance ratio, in good agreement with the computed value at the MP2(full)/cc-pVTZ level of approximation. The UV/Vis and resonance Raman spectra also show the occurrence of the conformational equilibrium in the liquid phase, with a moderate post-resonance Raman signature associated with the 350 nm electronic absorption.

  14. Generalized orbifold construction for conformal nets

    NASA Astrophysics Data System (ADS)

    Bischoff, Marcel

    Let ℬ be a conformal net. We give the notion of a proper action of a finite hypergroup K acting by vacuum preserving unital completely positive (so-called stochastic) maps on ℬ which generalizes the proper action of a finite group G. Taking the fixed point under such an action gives a finite index subnet ℬK of ℬ, which generalizes the G-orbifold net. Conversely, we show that if 𝒜⊂ℬ is a finite inclusion of conformal nets, then 𝒜 is a generalized orbifold 𝒜 = ℬK of the conformal net ℬ by a unique finite hypergroup K. There is a Galois correspondence between intermediate nets ℬK ⊂𝒜⊂ℬ and subhypergroups L ⊂ K given by 𝒜 = ℬL. In this case, the fixed point of ℬK ⊂𝒜 is the generalized orbifold by the hypergroup of double cosets L∖K/L. If 𝒜⊂ℬ is a finite index inclusion of completely rational nets, we show that the inclusion 𝒜(I) ⊂ℬ(I) is conjugate to an intermediate subfactor of a Longo-Rehren inclusion. This implies that if ℬ is a holomorphic net, and K acts properly on ℬ, then there is a unitary fusion category ℱ which is a categorification of K and Rep(ℬK) is braided equivalent to the Drinfel’d center Z(ℱ). More generally, if ℬ is a completely rational conformal net and K acts properly on ℬ, then there is a unitary fusion category ℱ extending Rep(ℬ), such that K is given by the double cosets of the fusion ring of ℱ by the Verlinde fusion ring of ℬ and Rep(ℬK) is braided equivalent to the Müger centralizer of Rep(ℬ) in the Drinfel’d center Z(ℱ).

  15. ACHIEVEMENT MOTIVATION, AFFILIATION MOTIVATION, AND TASK DIFFICULTY AS DETERMINANTS OF SOCIAL CONFORMITY

    DTIC Science & Technology

    subjected to contrived group pressures toward erroneous perceptual judgments. An analysis of variance of frequencies of conforming behavior revealed (a... conformity to group pressures disappear when predispositional motivational factors are controlled. (Author)...Extending from the differentiation of normative and informational processes of social influence an investigation of interactions between two

  16. Conformational preferences and pKa value of cysteine residue.

    PubMed

    Lee, Joo Yun; Byun, Byung Jin; Kang, Young Kee

    2008-09-11

    The conformational preferences of the Cys dipeptides with thiol and thiolate groups (Ac-Cys-NHMe and Ac-Cys (-)-NHMe, respectively) and the apparent (i.e., macroscopic) p K a value of the Cys dipeptide have been studied at the hybrid density functional B3LYP/6-311++G(d,p)//B3LYP/6-31+G(d) level with the conductor-like polarizable continuum model in the gas phase and in water. The hydrogen bonds and/or favorable interactions between the backbone and the thiol group of the side chain resulted in the different conformational preferences of the Cys and Cys (-) dipeptides from those of the Ala dipeptide in the gas phase and in water, although the preferred conformations of the Cys dipeptide are in part similar to those of the Ala dipeptide. In particular, the interactions between the thiolate group and the backbone amide groups appear to play a role in stabilizing the alpha- or 3 10-helical conformations for the Cys (-) dipeptide in the gas phase and in water. The p K a value of the Cys residue is estimated to be 8.58 at 25 degrees C using the statistically weighted free energies of all feasible conformations for the Cys and Cys (-) dipeptides in the gas phase and solvation free energies, which is consistent with the observed values of 8.3 and 8.22 +/- 0.16.

  17. Conformational analysis of polymethine dyes derived from the 2-azaazulene

    NASA Astrophysics Data System (ADS)

    Ryabitskii, Aleksey B.; Bricks, Julia L.; Kachkovskii, Aleksey D.; Kurdyukov, Vladimir V.

    2012-01-01

    A systematic investigation of the conformational structure was performed for the series of symmetrical and unsymmetrical mono-, tri-, pentamethine cyanines, and styryl dyes bearing 2-azaazulenium terminal group. The rotation energy barriers of terminal groups were determined via the dynamic variable temperature NMR experiments. The conformational transformation energy was calculated by quantum chemical methods (B3LYP and M05-2X) both for the cases of considering the solvent influence and not tacking it into account. Based on the comparison of theoretical and experimental data, relative electron-donating abilities and geometrical features of the heterocyclic terminal groups in 2-azaazulenium dyes were estimated. The arrangement of certain heterocyclic nuclei in order of basicity by considering the results of the dynamic NMR investigations was proposed. Influence of the conjugated chain length and the solvent nature on the conformational lability of the investigated dye molecules was discussed.

  18. Evidence for weak or linear conformity but not for hyper-conformity in an everyday social learning context.

    PubMed

    Claidière, Nicolas; Bowler, Mark; Whiten, Andrew

    2012-01-01

    Conformity is thought to be an important force in cultural evolution because it has the potential to stabilize cooperation in large groups, potentiate group selection and thus explain uniquely human behaviors. However, the effects of such conformity on cultural and biological evolution will depend much on the way individuals are influenced by the frequency of alternative behavioral options witnessed. Theoretical modeling has suggested that only what we refer to as 'hyper-conformity', an exaggerated tendency to perform the most frequent behavior witnessed in other individuals, is able to increase within-group homogeneity and between-group diversity, for instance. Empirically however, few experiments have addressed how the frequency of behavior witnessed affects behavior. Accordingly we performed an experiment to test for the presence of conformity in a natural situation with humans. Visitors to a Zoo exhibit were invited to write or draw answers to questions on A5 cards and potentially win a small prize. We manipulated the proportion of existing writings versus drawings visible to visitors and measured the proportion of written cards submitted. We found a strong and significant effect of the proportion of text displayed on the proportion of text in the answers, thus demonstrating social learning. We show that this effect is approximately linear, with potentially a small, weak-conformist component but no hyper-conformist one. The present experiment therefore provides evidence for linear conformity in humans in a very natural context.

  19. 40 CFR 93.154 - Conformity analysis.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Conformity analysis. 93.154 Section 93...) DETERMINING CONFORMITY OF FEDERAL ACTIONS TO STATE OR FEDERAL IMPLEMENTATION PLANS Determining Conformity of General Federal Actions to State or Federal Implementation Plans § 93.154 Conformity analysis. Any...

  20. Self-Dual Conformal Gravity

    NASA Astrophysics Data System (ADS)

    Dunajski, Maciej; Tod, Paul

    2014-10-01

    We find necessary and sufficient conditions for a Riemannian four-dimensional manifold ( M, g) with anti-self-dual Weyl tensor to be locally conformal to a Ricci-flat manifold. These conditions are expressed as the vanishing of scalar and tensor conformal invariants. The invariants obstruct the existence of parallel sections of a certain connection on a complex rank-four vector bundle over M. They provide a natural generalisation of the Bach tensor which vanishes identically for anti-self-dual conformal structures. We use the obstructions to demonstrate that LeBrun's anti-self-dual metrics on connected sums of s are not conformally Ricci-flat on any open set. We analyze both Riemannian and neutral signature metrics. In the latter case we find all anti-self-dual metrics with a parallel real spinor which are locally conformal to Einstein metrics with non-zero cosmological constant. These metrics admit a hyper-surface orthogonal null Killing vector and thus give rise to projective structures on the space of β-surfaces.

  1. Toward Understanding the Conformal Gravity

    NASA Astrophysics Data System (ADS)

    Berezin, V. A.; Dokuchaev, V. I.; Eroshenko, Yu. N.

    2017-03-01

    We constructed the conformally invariant model for scalar particle creation induced by strong gravitational fields. Starting from the usual hydrodynamic description of the particle motion written in the Eulerian coordinates, we substituted the particle number conservation law (which enters the formalism) by the particle creation law, proportional to the square of the Weyl tensor, following the famous result by Ya. B. Zel'dovich and A. A. Starobinsky. Then, demanding the conformal invariance of the whole dynamical system, we have got both the Weyl-conformal gravity and the Einstein-Hilbert dilaton gravity action integral. Thus, we obtained something like the induced gravity suggested first by A. D. Sakharov. It is shown that the resulting system is self-consistent.

  2. Partial masslessness and conformal gravity

    NASA Astrophysics Data System (ADS)

    Deser, S.; Joung, E.; Waldron, A.

    2013-05-01

    We use conformal, but ghostful, Weyl gravity to study its ghost-free, second derivative, partially massless (PM) spin-2 component in the presence of Einstein gravity with positive cosmological constant. Specifically, we consider both gravitational- and self-interactions of PM via the fully nonlinear factorization of conformal gravity’s Bach tensor into Einstein times Schouten operators. We find that extending PM beyond linear order suffers from familiar higher spin consistency obstructions: it propagates only in Einstein backgrounds, and the conformal gravity route generates only the usual safe, Noether, cubic order vertices. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Higher spin theories and holography’.

  3. Universality class in conformal inflation

    SciTech Connect

    Kallosh, Renata; Linde, Andrei E-mail: alinde@stanford.edu

    2013-07-01

    We develop a new class of chaotic inflation models with spontaneously broken conformal invariance. Observational consequences of a broad class of such models are stable with respect to strong deformations of the scalar potential. This universality is a critical phenomenon near the point of enhanced symmetry, SO(1,1), in case of conformal inflation. It appears because of the exponential stretching of the moduli space and the resulting exponential flattening of scalar potentials upon switching from the Jordan frame to the Einstein frame in this class of models. This result resembles stretching and flattening of inhomogeneities during inflationary expansion. It has a simple interpretation in terms of velocity versus rapidity near the Kähler cone in the moduli space, similar to the light cone of special theory of relativity. This effect makes inflation possible even in the models with very steep potentials. We describe conformal and superconformal versions of this cosmological attractor mechanism.

  4. Conformal deposition of LPCVD TEOS

    NASA Astrophysics Data System (ADS)

    McCann, Paul; Somasundram, Kumar; Byrne, Stephen; Nevin, Andrew

    2001-09-01

    The step coverage of dielectrics is important for the microelectronics industry and critical to Micro-machined products and High Voltage MEMS drivers. The techniques used to fabricate MEMS structures require void free refill processes and even film deposition along deep trenches to protect against etch chemistries. High voltage drivers used to actuate MEMS devices benefit from dielectric isolation, which reduces the need for large tub formation between devices. It also enables 'system on chip' solutions for MEMs devices and protection against voltage spikes. This paper presents a process developed at Analog Devices Belfast that enables an LPCVD TEOS furnace to perform a highly conformal trench refill without equipment modification. The conformality is over 95% for 20 micrometer deep trenches and maintains a conformality greater than 85% in 50 micrometer deep trenches. This compares with 75% conformality which is considered excellent for 20 micrometer trench refills obtained using previous LPCVD TEOS processing. The process is shown to have benefits in conformality, breakdown voltage, and stress over standard trench fill processes including Ozone TEOS. The densification of the TEOS film has been optimized for electrical parameters using CV and IV techniques, while XPS, FTIR and spectroscopic ellipsometry are used for physical characterization. Stress is a very important parameter for micro-machining and the conformal TEOS has a film stress which is tensile 30 - 40 MPa as deposited and compressive 100 MPa after densification. The breakdown voltage has been measured at 8.5 MV/cm compared to 7.5 - 9 MV/cm for a typical densified TEOS film and the refractive index is 1.456 compared to 1.465 for a thermal oxide. Analog Devices Belfast is part of the Micro-machined Products division and provides SOI and customized SOI for the MEMs and IC market.

  5. Algebraic orbifold conformal field theories

    PubMed Central

    Xu, Feng

    2000-01-01

    The unitary rational orbifold conformal field theories in the algebraic quantum field theory and subfactor theory framework are formulated. Under general conditions, it is shown that the orbifold of a given unitary rational conformal field theory generates a unitary modular category. Many new unitary modular categories are obtained. It is also shown that the irreducible representations of orbifolds of rank one lattice vertex operator algebras give rise to unitary modular categories and determine the corresponding modular matrices, which has been conjectured for some time. PMID:11106383

  6. SUSY Unparticle and Conformal Sequestering

    SciTech Connect

    Nakayama, Yu; Nakayama, Yu

    2007-07-17

    We investigate unparticle physics with supersymmetry (SUSY). The SUSY breaking effects due to the gravity mediation induce soft masses for the SUSY unparticles and hence break the conformal invariance. The unparticle physics observable in near future experiments is only consistent if the SUSY breakingeffects from the hidden sector to the standard model sector are dominated by the gauge mediation, or if the SUSY breaking effects to the unparticle sector are sufficiently sequestered. We argue that the natural realization of the latter possibility is the conformal sequestering scenario.

  7. Nonlocal gravity: Conformally flat spacetimes

    NASA Astrophysics Data System (ADS)

    Bini, Donato; Mashhoon, Bahram

    2016-04-01

    The field equations of the recent nonlocal generalization of Einstein’s theory of gravitation are presented in a form that is reminiscent of general relativity. The implications of the nonlocal field equations are studied in the case of conformally flat spacetimes. Even in this simple case, the field equations are intractable. Therefore, to gain insight into the nature of these equations, we investigate the structure of nonlocal gravity (NLG) in 2D spacetimes. While any smooth 2D spacetime is conformally flat and satisfies Einstein’s field equations, only a subset containing either a Killing vector or a homothetic Killing vector can satisfy the field equations of NLG.

  8. Social influence: compliance and conformity.

    PubMed

    Cialdini, Robert B; Goldstein, Noah J

    2004-01-01

    This review covers recent developments in the social influence literature, focusing primarily on compliance and conformity research published between 1997 and 2002. The principles and processes underlying a target's susceptibility to outside influences are considered in light of three goals fundamental to rewarding human functioning. Specifically, targets are motivated to form accurate perceptions of reality and react accordingly, to develop and preserve meaningful social relationships, and to maintain a favorable self-concept. Consistent with the current movement in compliance and conformity research, this review emphasizes the ways in which these goals interact with external forces to engender social influence processes that are subtle, indirect, and outside of awareness.

  9. Epigenetic Dominance of Prion Conformers

    PubMed Central

    Saijo, Eri; Kang, Hae-Eun; Bian, Jifeng; Bowling, Kristi G.; Browning, Shawn; Kim, Sehun; Hunter, Nora; Telling, Glenn C.

    2013-01-01

    Although they share certain biological properties with nucleic acid based infectious agents, prions, the causative agents of invariably fatal, transmissible neurodegenerative disorders such as bovine spongiform encephalopathy, sheep scrapie, and human Creutzfeldt Jakob disease, propagate by conformational templating of host encoded proteins. Once thought to be unique to these diseases, this mechanism is now recognized as a ubiquitous means of information transfer in biological systems, including other protein misfolding disorders such as those causing Alzheimer's and Parkinson's diseases. To address the poorly understood mechanism by which host prion protein (PrP) primary structures interact with distinct prion conformations to influence pathogenesis, we produced transgenic (Tg) mice expressing different sheep scrapie susceptibility alleles, varying only at a single amino acid at PrP residue 136. Tg mice expressing ovine PrP with alanine (A) at (OvPrP-A136) infected with SSBP/1 scrapie prions propagated a relatively stable (S) prion conformation, which accumulated as punctate aggregates in the brain, and produced prolonged incubation times. In contrast, Tg mice expressing OvPrP with valine (V) at 136 (OvPrP-V136) infected with the same prions developed disease rapidly, and the converted prion was comprised of an unstable (U), diffusely distributed conformer. Infected Tg mice co-expressing both alleles manifested properties consistent with the U conformer, suggesting a dominant effect resulting from exclusive conversion of OvPrP-V136 but not OvPrP-A136. Surprisingly, however, studies with monoclonal antibody (mAb) PRC5, which discriminates OvPrP-A136 from OvPrP-V136, revealed substantial conversion of OvPrP-A136. Moreover, the resulting OvPrP-A136 prion acquired the characteristics of the U conformer. These results, substantiated by in vitro analyses, indicated that co-expression of OvPrP-V136 altered the conversion potential of OvPrP-A136 from the S to the

  10. Conformational Entropy of Intrinsically Disordered Proteins from Amino Acid Triads

    PubMed Central

    Baruah, Anupaul; Rani, Pooja; Biswas, Parbati

    2015-01-01

    This work quantitatively characterizes intrinsic disorder in proteins in terms of sequence composition and backbone conformational entropy. Analysis of the normalized relative composition of the amino acid triads highlights a distinct boundary between globular and disordered proteins. The conformational entropy is calculated from the dihedral angles of the middle amino acid in the amino acid triad for the conformational ensemble of the globular, partially and completely disordered proteins relative to the non-redundant database. Both Monte Carlo (MC) and Molecular Dynamics (MD) simulations are used to characterize the conformational ensemble of the representative proteins of each group. The results show that the globular proteins span approximately half of the allowed conformational states in the Ramachandran space, while the amino acid triads in disordered proteins sample the entire range of the allowed dihedral angle space following Flory’s isolated-pair hypothesis. Therefore, only the sequence information in terms of the relative amino acid triad composition may be sufficient to predict protein disorder and the backbone conformational entropy, even in the absence of well-defined structure. The predicted entropies are found to agree with those calculated using mutual information expansion and the histogram method. PMID:26138206

  11. Conformation of poly(γ-glutamic acid) in aqueous solution.

    PubMed

    Muroga, Yoshio; Nakaya, Asami; Inoue, Atsuki; Itoh, Daiki; Abiru, Masaya; Wada, Kaori; Takada, Masako; Ikake, Hiroki; Shimizu, Shigeru

    2016-04-01

    Local conformation and overall conformation of poly(γ-DL-glutamic acid) (PγDLGA) and poly(γ-L-glutamic acid) (PγLGA) in aqueous solution was studied as a function of degree of ionization ε by (1) H-NMR, circular dichroism, and potentiometric titration. It was clarified that their local conformation is represented by random coil over an entire ε range and their overall conformation is represented by expanded random-coil in a range of ε > ε(*) , where ε(*) is about 0.3, 0.35, 0.45, and 0.5 for added-salt concentration of 0.02M, 0.05M, 0.1M, and 0.2M, respectively. In a range of ε < ε(*) , however, ε dependence of their overall conformation is significantly differentiated from each other. PγDLGA tends to aggregate intramolecularly and/or intermolecularly with decreasing ε, but PγLGA still behaves as expanded random-coil. It is speculated that spatial arrangement of adjacent carboxyl groups along the backbone chain essentially affects the overall conformation of PγGA in acidic media.

  12. Near-infrared laser-induced generation of three rare conformers of glycolic acid.

    PubMed

    Halasa, Anna; Lapinski, Leszek; Reva, Igor; Rostkowska, Hanna; Fausto, Rui; Nowak, Maciej J

    2014-07-31

    Structural transformations were induced in conformers of glycolic acid by selective excitation with monochromatic tunable near-infrared laser light. For the compound isolated in Ar matrixes, near-IR excitation led to generation of two higher-energy conformers (GAC; AAT) differing from the most stable SSC form by 180° rotation around the C-C bond. A detailed investigation of this transformation revealed that one conformer (GAC) is produced directly from the near-IR-excited most stable conformer. The other higher-energy conformer (AAT) was effectively generated only upon excitation of the primary photoproduct (GAC) with another near-IR photon. Once these higher-energy conformers of glycolic acid were generated in an Ar matrix, they could be subsequently transformed into one another upon selective near-IR excitations. Interestingly, no repopulation of the initial most stable SSC conformer occurred upon near-IR excitation of the higher-energy forms of the compound isolated in solid Ar. A dramatically different picture of near-IR-induced conformational transformations was observed for glycolic acid isolated in N2 matrixes. In this case, upon near-IR excitation, the most stable SSC form converted solely into a new conformer (SST), where the acid OH group is rotated by 180°. This conformational transformation was found to be photoreversible. Moreover, SST conformer, photoproduced in the N2 matrix, spontaneously converted to the most stable SSC form of glycolic acid, when the matrix was kept at cryogenic temperature and in the dark.

  13. Vibrational spectrum, ab initio calculations, conformational equilibria and torsional modes of 1,3-dichloropropane

    NASA Astrophysics Data System (ADS)

    Duffy, Daniel J.; Quenneville, Jason; Baumbaugh, T. M.; Kitchener, S. A.; McCormick, R. K.; Dormady, C. N.; Croce, T. A.; Navabi, A.; Stidham, Howard D.; Hsu, Shaw L.; Guirgis, Gamil A.; Deng, Shiping; Durig, James R.

    2004-02-01

    Ab initio calculations are reported for three of four possible conformers of 1,3-dichloropropane. The fourth conformer, with C s symmetry, has a predicted enthalpy difference of more than 1500 cm -1 from the most stable conformer from each calculation regardless of the basis set used, so there is little chance of observing it. Thus, there is no evidence in the infrared or Raman spectrum of the presence of a fourth conformer. The order of stability given by the ab initio calculations is C 2(GG)>C 1(AG)>C 2v(AA)>C s(GG'), where A indicates the anti form for one of the CH 2Cl groups and G indicates the gauche conformation for the other CH 2Cl group relative to the plane of the carbon atoms. Almost every band observed can be confidently assigned to one or another of the conformers. Many observed bands proved to be of a composite nature, with several nearly coincident vibrations of different conformers contributing to the band contour. Nonetheless, a complete assignment of fundamentals is possible for the most stable C 2 conformer, and 5 of the fundamentals of the C 2v conformer and 13 those of the C 1 conformer can be confidently assigned.

  14. Correspondence between Asymptotically Flat Spacetimes and Nonrelativistic Conformal Field Theories

    SciTech Connect

    Bagchi, Arjun

    2010-10-22

    We find a surprising connection between asymptotically flat spacetimes and nonrelativistic conformal systems in one lower dimension. The Bondi-Metzner-Sachs (BMS) group is the group of asymptotic isometries of flat Minkowski space at null infinity. This is known to be infinite dimensional in three and four dimensions. We show that the BMS algebra in 3 dimensions is the same as the 2D Galilean conformal algebra (GCA) which is of relevance to nonrelativistic conformal symmetries. We further justify our proposal by looking at a Penrose limit on a radially infalling null ray inspired by nonrelativistic scaling and obtain a flat metric. The BMS{sub 4} algebra is also discussed and found to be the same as another class of GCA, called semi-GCA, in three dimensions. We propose a general BMS-GCA correspondence. Some consequences are discussed.

  15. Molecular mechanics conformational analysis of tylosin

    NASA Astrophysics Data System (ADS)

    Ivanov, Petko M.

    1998-01-01

    The conformations of the 16-membered macrolide antibiotic tylosin were studied with molecular mechanics (AMBER∗ force field) including modelling of the effect of the solvent on the conformational preferences (GB/SA). A Monte Carlo conformational search procedure was used for finding the most probable low-energy conformations. The present study provides complementary data to recently reported analysis of the conformations of tylosin based on NMR techniques. A search for the low-energy conformations of protynolide, a 16-membered lactone containing the same aglycone as tylosin, was also carried out, and the results were compared with the observed conformation in the crystal as well as with the most probable conformations of the macrocyclic ring of tylosin. The dependence of the results on force field was also studied by utilizing the MM3 force field. Some particular conformations were computed with the semiempirical molecular orbital methods AM1 and PM3.

  16. Correct Representation of Conformational Equilibria.

    ERIC Educational Resources Information Center

    Fulop, F.; And Others

    1983-01-01

    In representing conformational equilibria of compounds having only one chiral center, erroneous formulas showing different antipodes on the two sides of the equilibrium are rare. In contrast, with compounds having two or more chiral centers especially with saturated heterocycles, this erroneous representation occurs frequently in the chemical…

  17. Conformal mapping for multiple terminals

    NASA Astrophysics Data System (ADS)

    Wang, Weimin; Ma, Wenying; Wang, Qiang; Ren, Hao

    2016-11-01

    Conformal mapping is an important mathematical tool that can be used to solve various physical and engineering problems in many fields, including electrostatics, fluid mechanics, classical mechanics, and transformation optics. It is an accurate and convenient way to solve problems involving two terminals. However, when faced with problems involving three or more terminals, which are more common in practical applications, existing conformal mapping methods apply assumptions or approximations. A general exact method does not exist for a structure with an arbitrary number of terminals. This study presents a conformal mapping method for multiple terminals. Through an accurate analysis of boundary conditions, additional terminals or boundaries are folded into the inner part of a mapped region. The method is applied to several typical situations, and the calculation process is described for two examples of an electrostatic actuator with three electrodes and of a light beam splitter with three ports. Compared with previously reported results, the solutions for the two examples based on our method are more precise and general. The proposed method is helpful in promoting the application of conformal mapping in analysis of practical problems.

  18. Conformal mapping for multiple terminals.

    PubMed

    Wang, Weimin; Ma, Wenying; Wang, Qiang; Ren, Hao

    2016-11-10

    Conformal mapping is an important mathematical tool that can be used to solve various physical and engineering problems in many fields, including electrostatics, fluid mechanics, classical mechanics, and transformation optics. It is an accurate and convenient way to solve problems involving two terminals. However, when faced with problems involving three or more terminals, which are more common in practical applications, existing conformal mapping methods apply assumptions or approximations. A general exact method does not exist for a structure with an arbitrary number of terminals. This study presents a conformal mapping method for multiple terminals. Through an accurate analysis of boundary conditions, additional terminals or boundaries are folded into the inner part of a mapped region. The method is applied to several typical situations, and the calculation process is described for two examples of an electrostatic actuator with three electrodes and of a light beam splitter with three ports. Compared with previously reported results, the solutions for the two examples based on our method are more precise and general. The proposed method is helpful in promoting the application of conformal mapping in analysis of practical problems.

  19. Conformal mapping for multiple terminals

    PubMed Central

    Wang, Weimin; Ma, Wenying; Wang, Qiang; Ren, Hao

    2016-01-01

    Conformal mapping is an important mathematical tool that can be used to solve various physical and engineering problems in many fields, including electrostatics, fluid mechanics, classical mechanics, and transformation optics. It is an accurate and convenient way to solve problems involving two terminals. However, when faced with problems involving three or more terminals, which are more common in practical applications, existing conformal mapping methods apply assumptions or approximations. A general exact method does not exist for a structure with an arbitrary number of terminals. This study presents a conformal mapping method for multiple terminals. Through an accurate analysis of boundary conditions, additional terminals or boundaries are folded into the inner part of a mapped region. The method is applied to several typical situations, and the calculation process is described for two examples of an electrostatic actuator with three electrodes and of a light beam splitter with three ports. Compared with previously reported results, the solutions for the two examples based on our method are more precise and general. The proposed method is helpful in promoting the application of conformal mapping in analysis of practical problems. PMID:27830746

  20. Temperature: Human Regulating, Ants Conforming

    ERIC Educational Resources Information Center

    Clopton, Joe R.

    2007-01-01

    Biological processes speed up as temperature rises. Procedures for demonstrating this with ants traveling on trails, and data gathered by students on the Argentine ant ("Linepithema humile") are presented. The concepts of temperature regulation and conformity are detailed with a focus on the processes rather than on terms that label the organisms.

  1. Logarithmic conformal field theory: beyond an introduction

    NASA Astrophysics Data System (ADS)

    Creutzig, Thomas; Ridout, David

    2013-12-01

    of the underlying chiral algebra and the modular data pertaining to the characters of the representations. Each of the archetypal logarithmic conformal field theories is studied here by first determining its irreducible spectrum, which turns out to be continuous, as well as a selection of natural reducible, but indecomposable, modules. This is followed by a detailed description of how to obtain character formulae for each irreducible, a derivation of the action of the modular group on the characters, and an application of the Verlinde formula to compute the Grothendieck fusion rules. In each case, the (genuine) fusion rules are known, so comparisons can be made and favourable conclusions drawn. In addition, each example admits an infinite set of simple currents, hence extended symmetry algebras may be constructed and a series of bulk modular invariants computed. The spectrum of such an extended theory is typically discrete and this is how the triplet model \\mathfrak {W} (1,2) arises, for example. Moreover, simple current technology admits a derivation of the extended algebra fusion rules from those of its continuous parent theory. Finally, each example is concluded by a brief description of the computation of some bulk correlators, a discussion of the structure of the bulk state space, and remarks concerning more advanced developments and generalizations. The final part gives a very short account of the theory of staggered modules, the (simplest class of) representations that are responsible for the logarithmic singularities that distinguish logarithmic theories from their rational cousins. These modules are discussed in a generality suitable to encompass all the examples met in this review and some of the very basic structure theory is proven. Then, the important quantities known as logarithmic couplings are reviewed for Virasoro staggered modules and their role as fundamentally important parameters, akin to the three-point constants of rational conformal field

  2. Conformational activation of ADAMTS13.

    PubMed

    South, Kieron; Luken, Brenda M; Crawley, James T B; Phillips, Rebecca; Thomas, Mari; Collins, Richard F; Deforche, Louis; Vanhoorelbeke, Karen; Lane, David A

    2014-12-30

    A disintegrin and metalloprotease with thrombospondin motifs 13 (ADAMTS13) is a metalloprotease that regulates von Willebrand factor (VWF) function. ADAMTS13-mediated proteolysis is determined by conformational changes in VWF, but also may depend on its own conformational activation. Kinetic analysis of WT ADAMTS13 revealed ∼ 2.5-fold reduced activity compared with ADAMTS13 lacking its C-terminal tail (MDTCS) or its CUB1-2 domains (WTΔCUB1-2), suggesting that the CUB domains naturally limit ADAMTS13 function. Consistent with this suggestion, WT ADAMTS13 activity was enhanced ∼ 2.5-fold by preincubation with either an anti-CUB mAb (20E9) or VWF D4CK (the natural binding partner for the CUB domains). Furthermore, the isolated CUB1-2 domains not only bound MDTCS, but also inhibited activity by up to 2.5-fold. Interestingly, a gain-of-function (GoF) ADAMTS13 spacer domain variant (R568K/F592Y/R660K/Y661F/Y665F) was ∼ 2.5-fold more active than WT ADAMTS13, but could not be further activated by 20E9 mAb or VWF D4CK and was unable to bind or to be inhibited by the CUB1-2 domains, suggesting that the inhibitory effects of the CUB domains involve an interaction with the spacer domain that is disrupted in GoF ADAMTS13. Electron microscopy demonstrated a "closed" conformation of WT ADAMTS13 and suggested a more "open" conformation for GoF ADAMTS13. The cryptic spacer domain epitope revealed by conformational unfolding also represents the core antigenic target for autoantibodies in thrombotic thrombocytopenic purpura. We propose that ADAMTS13 circulates in a closed conformation, which is maintained by a CUB-spacer domain binding interaction. ADAMTS13 becomes conformationally activated on demand through interaction of its C-terminal CUB domains with VWF, making it susceptible to immune recognition.

  3. Small-scale Conformity of the Virgo Cluster Galaxies

    NASA Astrophysics Data System (ADS)

    Lee, Hye-Ran; Lee, Joon Hyeop; Jeong, Hyunjin; Park, Byeong-Gon

    2016-06-01

    We investigate the small-scale conformity in color between bright galaxies and their faint companions in the Virgo Cluster. Cluster member galaxies are spectroscopically determined using the Extended Virgo Cluster Catalog and the Sloan Digital Sky Survey Data Release 12. We find that the luminosity-weighted mean color of faint galaxies depends on the color of adjacent bright galaxy as well as on the cluster-scale environment (gravitational potential index). From this result for the entire area of the Virgo Cluster, it is not distinguishable whether the small-scale conformity is genuine or if it is artificially produced due to cluster-scale variation of galaxy color. To disentangle this degeneracy, we divide the Virgo Cluster area into three sub-areas so that the cluster-scale environmental dependence is minimized: A1 (central), A2 (intermediate), and A3 (outermost). We find conformity in color between bright galaxies and their faint companions (color-color slope significance S ˜ 2.73σ and correlation coefficient {cc}˜ 0.50) in A2, where the cluster-scale environmental dependence is almost negligible. On the other hand, the conformity is not significant or very marginal (S ˜ 1.75σ and {cc}˜ 0.27) in A1. The conformity is not significant either in A3 (S ˜ 1.59σ and {cc}˜ 0.44), but the sample size is too small in this area. These results are consistent with a scenario in which the small-scale conformity in a cluster is a vestige of infallen groups and these groups lose conformity as they come closer to the cluster center.

  4. Conformational Analysis of Stiff Chiral Polymers with End-Constraints.

    PubMed

    Kim, Jin Seob; Chirikjian, Gregory S

    2006-01-01

    We present a Lie-group-theoretic method for the kinematic and dynamic analysis of chiral semi-flexible polymers with end constraints. The first is to determine the minimum energy conformations of semi-flexible polymers with end constraints, and the second is to perform normal mode analysis based on the determined minimum energy conformations. In this paper, we use concepts from the theory of Lie groups and principles of variational calculus to model such polymers as inextensible or extensible chiral elastic rods with coupling between twisting and bending stiffnesses, and/or between twisting and extension stiffnesses. This method is general enough to include any stiffness and chirality parameters in the context of elastic filament models with the quadratic elastic potential energy function. As an application of this formulation, the analysis of DNA conformations is discussed. We demonstrate our method with examples of DNA conformations in which topological properties such as writhe, twist, and linking number are calculated from the results of the proposed method. Given these minimum energy conformations, we describe how to perform the normal mode analysis. The results presented here build both on recent experimental work in which DNA mechanical properties have been measured, and theoretical work in which the mechanics of non-chiral elastic rods has been studied.

  5. Conformational Analysis of Stiff Chiral Polymers with End-Constraints

    PubMed Central

    Kim, Jin Seob; Chirikjian, Gregory S.

    2010-01-01

    We present a Lie-group-theoretic method for the kinematic and dynamic analysis of chiral semi-flexible polymers with end constraints. The first is to determine the minimum energy conformations of semi-flexible polymers with end constraints, and the second is to perform normal mode analysis based on the determined minimum energy conformations. In this paper, we use concepts from the theory of Lie groups and principles of variational calculus to model such polymers as inextensible or extensible chiral elastic rods with coupling between twisting and bending stiffnesses, and/or between twisting and extension stiffnesses. This method is general enough to include any stiffness and chirality parameters in the context of elastic filament models with the quadratic elastic potential energy function. As an application of this formulation, the analysis of DNA conformations is discussed. We demonstrate our method with examples of DNA conformations in which topological properties such as writhe, twist, and linking number are calculated from the results of the proposed method. Given these minimum energy conformations, we describe how to perform the normal mode analysis. The results presented here build both on recent experimental work in which DNA mechanical properties have been measured, and theoretical work in which the mechanics of non-chiral elastic rods has been studied. PMID:20198114

  6. Fake conformal symmetry in unimodular gravity

    NASA Astrophysics Data System (ADS)

    Oda, Ichiro

    2016-08-01

    We study Weyl symmetry (local conformal symmetry) in unimodular gravity. It is shown that the Noether currents for both Weyl symmetry and global scale symmetry vanish exactly as in conformally invariant scalar-tensor gravity. We clearly explain why in the class of conformally invariant gravitational theories, the Noether currents vanish by starting with conformally invariant scalar-tensor gravity. Moreover, we comment on both classical and quantum-mechanical equivalences in Einstein's general relativity, conformally invariant scalar-tensor gravity, and the Weyl-transverse gravity. Finally, we discuss the Weyl current in the conformally invariant scalar action and see that it is also vanishing.

  7. Conformational preferences of γ-aminobutyric acid in the gas phase and in water

    NASA Astrophysics Data System (ADS)

    Song, Il Keun; Kang, Young Kee

    2012-09-01

    The conformational study of γ-aminobutyric acid (GABA) has been carried out at the M06-2X/cc-pVTZ level of theory in the gas phase and the SMD M06-2X/cc-pVTZ level of theory in water. In the gas phase, the folded conformation gG1 with gauche- and gauche+ conformations for the Cβsbnd Cα and Cγsbnd Cβ bonds, respectively, is found to be lowest in energy and enthalpy, which can be ascribed to the favored hyperconjugative n → π* interaction between the lone electron pair of the amine nitrogen atom and the Cdbnd O bond of the carboxylic group and the favored antiparallel dipole-dipole interaction between the Nsbnd H bond and the Cdbnd O bond. In addition, the intramolecular hydrogen bonds between the carboxylic group and the amine Nsbnd H group have contributed to stabilize some low-energy conformers. However, the most preferred conformation is found to be tG1 and more stable by 0.4 kcal/mol in ΔG than the conformer gG1, in which the favored entropic term due to the conformational flexibility and the other favored n → σ*, σ → σ*, and π → σ* interactions seem to play a role. The conformational preferences of the neutral GABA calculated by ΔG's are reasonably consistent with the populations deduced from FT microwave spectroscopy in supersonic jets combined with laser ablation. In water, the two folded conformers Gg and gG of the zwitterionic GABA are dominantly populated, each of which has the population of 47%, and the hydrogen bond between the ammonium Nsbnd H group and the lone electron pair of the Csbnd O- group seems to be crucial in stabilizing these conformers. Our calculated result that the folded conformers preferentially exist in water is consistent with the 1H NMR experiments in D2O.

  8. Pulmonary Toxicity in Stage III Non-Small Cell Lung Cancer Patients Treated With High-Dose (74 Gy) 3-Dimensional Conformal Thoracic Radiotherapy and Concurrent Chemotherapy Following Induction Chemotherapy: A Secondary Analysis of Cancer and Leukemia Group B (CALGB) Trial 30105

    SciTech Connect

    Salama, Joseph K.; Stinchcombe, Thomas E.; Gu Lin; Wang Xiaofei; Morano, Karen; Bogart, Jeffrey A.; Crawford, Jeffrey C.; Socinski, Mark A.; Blackstock, A. William; Vokes, Everett E.

    2011-11-15

    Purpose: Cancer and Leukemia Group B (CALGB) 30105 tested two different concurrent chemoradiotherapy platforms with high-dose (74 Gy) three-dimensional conformal radiotherapy (3D-CRT) after two cycles of induction chemotherapy for Stage IIIA/IIIB non-small cell lung cancer (NSCLC) patients to determine if either could achieve a primary endpoint of >18-month median survival. Final results of 30105 demonstrated that induction carboplatin and gemcitabine and concurrent gemcitabine 3D-CRT was not feasible because of treatment-related toxicity. However, induction and concurrent carboplatin/paclitaxel with 74 Gy 3D-CRT had a median survival of 24 months, and is the basis for the experimental arm in CALGB 30610/RTOG 0617/N0628. We conducted a secondary analysis of all patients to determine predictors of treatment-related pulmonary toxicity. Methods and Materials: Patient, tumor, and treatment-related variables were analyzed to determine their relation with treatment-related pulmonary toxicity. Results: Older age, higher N stage, larger planning target volume (PTV)1, smaller total lung volume/PTV1 ratio, larger V20, and larger mean lung dose were associated with increasing pulmonary toxicity on univariate analysis. Multivariate analysis confirmed that V20 and nodal stage as well as treatment with concurrent gemcitabine were associated with treatment-related toxicity. A high-risk group comprising patients with N3 disease and V20 >38% was associated with 80% of Grades 3-5 pulmonary toxicity cases. Conclusions: Elevated V20 and N3 disease status are important predictors of treatment related pulmonary toxicity in patients treated with high-dose 3D-CRT and concurrent chemotherapy. Further studies may use these metrics in considering patients for these treatments.

  9. Quantification of free ligand conformational preferences by NMR and their relationship to the bioactive conformation.

    PubMed

    Blundell, Charles D; Packer, Martin J; Almond, Andrew

    2013-09-01

    Accurate unbound solution 3D-structures of ligands provide unique opportunities for medicinal chemistry and, in particular, a context to understand binding thermodynamics and kinetics. Previous methods of deriving these 3D-structures have had neither the accuracy nor resolution needed for drug design and have not yet realized their potential. Here, we describe and apply a NMR methodology to the aminoglycoside streptomycin that can accurately quantify accessible 3D-space and rank the occupancy of observed conformers to a resolution that enables medicinal chemistry understanding and design. Importantly, it is based upon conventional small molecule NMR techniques and can be performed in physiologically-relevant solvents. The methodology uses multiple datasets, an order of magnitude more experimental data than previous NMR approaches and a dynamic model during refinement, is independent of computational chemistry and avoids the problem of virtual conformations. The refined set of solution 3D-shapes for streptomycin can be grouped into two major families, of which the most populated is almost identical to the 30S ribosomal subunit bioactive shape. We therefore propose that accurate unbound ligand solution conformations may, in some cases, provide a subsidiary route to bioactive shape without crystallography. This experimental technique opens up new opportunities for drug design and more so when complemented with protein co-crystal structures, SAR data and pharmacophore modeling.

  10. Conformal Window and Correlation Functions in Lattice Conformal QCD

    NASA Astrophysics Data System (ADS)

    Iwasaki, Y.

    We discuss various aspects of Conformal Field Theories on the Lattice. We mainly investigate the SU(3) gauge theory with Nf degenerate fermions in the fundamental representation, employing the one-plaquette gauge action and the Wilson fermion action. First we make a brief review of our previous works on the phase structure of lattice gauge theories in terms of the gauge coupling constant and the quark mass. We thereby clarify the reason why we conjecture that the conformal window is 7 ≤ Nf ≤ 16. Secondly, we introduce a new concept, "conformal theories with IR cutof" and point out that any numerical simulation on a lattice is bounded by an IR cutoff ∧IR. Then we make predictions that when Nf is within the conformal window, the propagator of a meson G(t) behaves at large t, as G(t) = c exp (-mHt)/tα, that is, a modified Yukawa-type decay form, instead of the usual exponential decay form exp (-mHt), in the small quark mass region. This holds on an any lattice for any coupling constant g, as far as g is between 0 and g*, where g* is the IR fixed point. We verify that numerical results really satisfy the predictions for the Nf = 7 case and the Nf = 16 case. Thirdly, we discuss small number of flavors (Nf = 2 ˜ 6) QCD at finite temperatures. We point out theoretically and verify numerically that the correlation functions at T/Tc > 1 exhibit the characteristics of the conformal function with IR cutoff, an exponential decay with power correction. Investigating our numerical data by a new method which we call the "local-analysis" of propagators, we observe that the Nf = 7 case and the Nf = 2 at T ˜ 2Tc case are similar to each other, while the Nf = 16 case and the Nf = 2 at T = 102 ˜ 105Tc cases are similar to each other. Further, we observe our data are consistent with the picture that the Nf = 7 case and the Nf = 2 at T ˜ 2Tc case are close to the meson unparticle model. On the other hand, the Nf = 16 case and the Nf = 2 at T = 102 ˜ 105Tc cases are close to

  11. Gauge natural formulation of conformal gravity

    SciTech Connect

    Campigotto, M.; Fatibene, L.

    2015-03-15

    We consider conformal gravity as a gauge natural theory. We study its conservation laws and superpotentials. We also consider the Mannheim and Kazanas spherically symmetric vacuum solution and discuss conserved quantities associated to conformal and diffeomorphism symmetries.

  12. Killing Initial Data on spacelike conformal boundaries

    NASA Astrophysics Data System (ADS)

    Paetz, Tim-Torben

    2016-08-01

    We analyze Killing Initial Data on Cauchy surfaces in conformally rescaled vacuum space-times satisfying Friedrich's conformal field equations. As an application, we derive the KID equations on a spacelike ℐ-.

  13. Evidence for Weak or Linear Conformity but Not for Hyper-Conformity in an Everyday Social Learning Context

    PubMed Central

    Claidière, Nicolas; Bowler, Mark; Whiten, Andrew

    2012-01-01

    Conformity is thought to be an important force in cultural evolution because it has the potential to stabilize cooperation in large groups, potentiate group selection and thus explain uniquely human behaviors. However, the effects of such conformity on cultural and biological evolution will depend much on the way individuals are influenced by the frequency of alternative behavioral options witnessed. Theoretical modeling has suggested that only what we refer to as ‘hyper-conformity’, an exaggerated tendency to perform the most frequent behavior witnessed in other individuals, is able to increase within-group homogeneity and between-group diversity, for instance. Empirically however, few experiments have addressed how the frequency of behavior witnessed affects behavior. Accordingly we performed an experiment to test for the presence of conformity in a natural situation with humans. Visitors to a Zoo exhibit were invited to write or draw answers to questions on A5 cards and potentially win a small prize. We manipulated the proportion of existing writings versus drawings visible to visitors and measured the proportion of written cards submitted. We found a strong and significant effect of the proportion of text displayed on the proportion of text in the answers, thus demonstrating social learning. We show that this effect is approximately linear, with potentially a small, weak-conformist component but no hyper-conformist one. The present experiment therefore provides evidence for linear conformity in humans in a very natural context. PMID:22363524

  14. A conformational study of hydroxyflavones by vibrational spectroscopy coupled to DFT calculations

    NASA Astrophysics Data System (ADS)

    Machado, N. F. L.; Batista de Carvalho, L. A. E.; Otero, J. C.; Marques, M. P. M.

    2013-05-01

    The conformational preferences of a series of hydroxyflavones were studied by Raman and FTIR spectroscopies, coupled to Density Functional Theory calculations. Special attention was paid to the effect of hydroxyl substitution, due to its importance on the biological activity of these compounds. Their conformational preferences were found to be determined mainly by the orientation of the hydroxylic groups at C7 and within the catechol moiety, leading to the occurrence of distinct conformers in the solid state. A complete assignment of the experimental spectra was carried out for these molecules, in the light of their most stable conformers and the corresponding predicted vibrational pattern.

  15. The two conformers of acetanilide unraveled using LA-MB-FTMW spectroscopy

    NASA Astrophysics Data System (ADS)

    Cabezas, C.; Varela, M.; Caminati, W.; Mata, S.; López, J. C.; Alonso, J. L.

    2011-07-01

    Acetanilide has been investigated by laser ablation molecular beam Fourier transform microwave LA-MB-FTMW spectroscopy. The rotational spectrum of both trans and cis conformers have been analyzed to determine the rotational and 14N quadrupole coupling the constants. The spectrum of the less abundant cis conformer has been assigned for the first time. The doublets observed for this conformer have been interpreted in terms of the tunneling motion between two equivalent non-planar conformations through a small barrier in which the acetamide group and phenyl ring plane are perpendicular. The results are compared with those of the related formanilide.

  16. Scale invariance implies conformal invariance for the three-dimensional Ising model.

    PubMed

    Delamotte, Bertrand; Tissier, Matthieu; Wschebor, Nicolás

    2016-01-01

    Using the Wilson renormalization group, we show that if no integrated vector operator of scaling dimension -1 exists, then scale invariance implies conformal invariance. By using the Lebowitz inequalities, we prove that this necessary condition is fulfilled in all dimensions for the Ising universality class. This shows, in particular, that scale invariance implies conformal invariance for the three-dimensional Ising model.

  17. Identification of Serine Conformers by Matrix-Isolation IR Spectroscopy Aided by Near-Infrared Laser-Induced Conformational Change, 2D Correlation Analysis, and Quantum Mechanical Anharmonic Computations.

    PubMed

    Najbauer, Eszter E; Bazsó, Gábor; Apóstolo, Rui; Fausto, Rui; Biczysko, Malgorzata; Barone, Vincenzo; Tarczay, György

    2015-08-20

    The conformers of α-serine were investigated by matrix-isolation IR spectroscopy combined with NIR laser irradiation. This method, aided by 2D correlation analysis, enabled unambiguously grouping the spectral lines to individual conformers. On the basis of comparison of at least nine experimentally observed vibrational transitions of each conformer with empirically scaled (SQM) and anharmonic (GVPT2) computed IR spectra, six conformers were identified. In addition, the presence of at least one more conformer in Ar matrix was proved, and a short-lived conformer with a half-life of (3.7 ± 0.5) × 10(3) s in N2 matrix was generated by NIR irradiation. The analysis of the NIR laser-induced conversions revealed that the excitation of the stretching overtone of both the side chain and the carboxylic OH groups can effectively promote conformational changes, but remarkably different paths were observed for the two kinds of excitations.

  18. Generative models of conformational dynamics.

    PubMed

    Langmead, Christopher James

    2014-01-01

    Atomistic simulations of the conformational dynamics of proteins can be performed using either Molecular Dynamics or Monte Carlo procedures. The ensembles of three-dimensional structures produced during simulation can be analyzed in a number of ways to elucidate the thermodynamic and kinetic properties of the system. The goal of this chapter is to review both traditional and emerging methods for learning generative models from atomistic simulation data. Here, the term 'generative' refers to a model of the joint probability distribution over the behaviors of the constituent atoms. In the context of molecular modeling, generative models reveal the correlation structure between the atoms, and may be used to predict how the system will respond to structural perturbations. We begin by discussing traditional methods, which produce multivariate Gaussian models. We then discuss GAMELAN (GRAPHICAL MODELS OF ENERGY LANDSCAPES), which produces generative models of complex, non-Gaussian conformational dynamics (e.g., allostery, binding, folding, etc.) from long timescale simulation data.

  19. Conformal Bootstrap in Mellin Space

    NASA Astrophysics Data System (ADS)

    Gopakumar, Rajesh; Kaviraj, Apratim; Sen, Kallol; Sinha, Aninda

    2017-02-01

    We propose a new approach towards analytically solving for the dynamical content of conformal field theories (CFTs) using the bootstrap philosophy. This combines the original bootstrap idea of Polyakov with the modern technology of the Mellin representation of CFT amplitudes. We employ exchange Witten diagrams with built-in crossing symmetry as our basic building blocks rather than the conventional conformal blocks in a particular channel. Demanding consistency with the operator product expansion (OPE) implies an infinite set of constraints on operator dimensions and OPE coefficients. We illustrate the power of this method in the ɛ expansion of the Wilson-Fisher fixed point by reproducing anomalous dimensions and, strikingly, obtaining OPE coefficients to higher orders in ɛ than currently available using other analytic techniques (including Feynman diagram calculations). Our results enable us to get a somewhat better agreement between certain observables in the 3D Ising model and the precise numerical values that have been recently obtained.

  20. Geodesics and submanifold structures in conformal geometry

    NASA Astrophysics Data System (ADS)

    Belgun, Florin

    2015-05-01

    A conformal structure on a manifold Mn induces natural second order conformally invariant operators, called Möbius and Laplace structures, acting on specific weight bundles of M, provided that n ≥ 3. By extending the notions of Möbius and Laplace structures to the case of surfaces and curves, we develop here the theory of extrinsic conformal geometry for submanifolds, find tensorial invariants of a conformal embedding, and use these invariants to characterize various notions of geodesic submanifolds.

  1. Stabilizing the boat conformation of cyclohexane rings

    SciTech Connect

    Dasgupta, S.; Goddard, W.A. III; Moldowan, J.M.; Carlson, R.M.K.; Goddard, W.A. III.

    1995-06-21

    In calculating the energetics for various conformers of the A, B, and C series of hopanoid hydrocarbons present in mature oil reservoirs, we find that the B series prefers the boat conformation (by 1.3-2.5 kcal/mol) for the D cyclohexane ring. We analyze the structural elements responsible for stabilizing this boat conformation, identify the key features, and illustrate how one might stabilize boat conformations of other systems. 5 refs., 3 figs., 2 tabs.

  2. DoD Biometric Conformity Assessment Initiative

    DTIC Science & Technology

    2005-04-01

    REPORT DATE APR 2005 2. REPORT TYPE 3. DATES COVERED 00-04-2005 to 00-06-2005 4. TITLE AND SUBTITLE DoD Biometric Conformity Assessment...Prescribed by ANSI Std Z39-18 dsp.dla.mil 21 DSP JOURNAL April/June 200522 The comprehensive discipline of conformity assess- ment involves conformance ... conformity assessment, and details the steps the DoD Biometrics Management Office (BMO) and its subordinate technology center, the DoD Biometrics Fusion

  3. Conformal microstrip arrays on cylinders

    NASA Astrophysics Data System (ADS)

    Ashkenazy, J.; Shtrikman, S.; Treves, D.

    1988-04-01

    Design and measured results for two X-band conformal microstrip arrays are presented. The two 4 x 4 arrays are built on the surface of a cylinder of small radius. They differ by the orientation of small radius. They differ by the orientation of the elements relative to the cylinder axis. The measured directivities and radiation patterns are in reasonable agreement with theoretical predictions.

  4. Conformal Antenna Array Design Handbook

    DTIC Science & Technology

    1981-09-01

    PLANAR ARRAY PHASE C LbP=IowITH CORRECT CONFORMAL ARRAY PHASE C NbPt NOe OF PhS&. SH-IFT UITSPII- NoP*.GT*1O CONRCLT PHASES ARE USED C TAP19PATTLRN...of Antenna Arrays, Radio Science , Vol. 3, May 1968, pp. 401-522. M. T. Ma, "Theory and Application of Antenna Arrays", Wiley, New York, 1974, Chapter

  5. Anomalies, conformal manifolds, and spheres

    DOE PAGES

    Gomis, Jaume; Hsin, Po-Shen; Komargodski, Zohar; ...

    2016-03-04

    The two-point function of exactly marginal operators leads to a universal contribution to the trace anomaly in even dimensions. We study aspects of this trace anomaly, emphasizing its interpretation as a sigma model, whose target space $M$ is the space of conformal field theories (a.k.a. the conformal manifold). When the underlying quantum field theory is supersymmetric, this sigma model has to be appropriately supersymmetrized. As examples, we consider in some detail $N$ = (2; 2) and $N$ = (0; 2) supersymmetric theories in d = 2 and $N$ = 2 supersymmetric theories in d = 4. This reasoning leads tomore » new information about the conformal manifolds of these theories, for example, we show that the manifold is K ahler-Hodge and we further argue that it has vanishing K ahler class. For $N$ = (2; 2) theories in d = 2 and N = 2 theories in d = 4 we also show that the relation between the sphere partition function and the K ahler potential of $M$ follows immediately from the appropriate sigma models that we construct. Ultimately, along the way we find several examples of potential trace anomalies that obey the Wess-Zumino consistency conditions, but can be ruled out by a more detailed analysis.« less

  6. Anomalies, conformal manifolds, and spheres

    SciTech Connect

    Gomis, Jaume; Hsin, Po-Shen; Komargodski, Zohar; Schwimmer, Adam; Seiberg, Nathan; Theisen, Stefan

    2016-03-04

    The two-point function of exactly marginal operators leads to a universal contribution to the trace anomaly in even dimensions. We study aspects of this trace anomaly, emphasizing its interpretation as a sigma model, whose target space $M$ is the space of conformal field theories (a.k.a. the conformal manifold). When the underlying quantum field theory is supersymmetric, this sigma model has to be appropriately supersymmetrized. As examples, we consider in some detail $N$ = (2; 2) and $N$ = (0; 2) supersymmetric theories in d = 2 and $N$ = 2 supersymmetric theories in d = 4. This reasoning leads to new information about the conformal manifolds of these theories, for example, we show that the manifold is K ahler-Hodge and we further argue that it has vanishing K ahler class. For $N$ = (2; 2) theories in d = 2 and N = 2 theories in d = 4 we also show that the relation between the sphere partition function and the K ahler potential of $M$ follows immediately from the appropriate sigma models that we construct. Ultimately, along the way we find several examples of potential trace anomalies that obey the Wess-Zumino consistency conditions, but can be ruled out by a more detailed analysis.

  7. Conformal Invariance of Graphene Sheets

    PubMed Central

    Giordanelli, I.; Posé, N.; Mendoza, M.; Herrmann, H. J.

    2016-01-01

    Suspended graphene sheets exhibit correlated random deformations that can be studied under the framework of rough surfaces with a Hurst (roughness) exponent 0.72 ± 0.01. Here, we show that, independent of the temperature, the iso-height lines at the percolation threshold have a well-defined fractal dimension and are conformally invariant, sharing the same statistical properties as Schramm-Loewner evolution (SLEκ) curves with κ = 2.24 ± 0.07. Interestingly, iso-height lines of other rough surfaces are not necessarily conformally invariant even if they have the same Hurst exponent, e.g. random Gaussian surfaces. We have found that the distribution of the modulus of the Fourier coefficients plays an important role on this property. Our results not only introduce a new universality class and place the study of suspended graphene membranes within the theory of critical phenomena, but also provide hints on the long-standing question about the origin of conformal invariance in iso-height lines of rough surfaces. PMID:26961723

  8. An extension theorem for conformal gauge singularities

    NASA Astrophysics Data System (ADS)

    Lübbe, Christian; Tod, Paul

    2009-11-01

    We analyze conformal gauge, or isotropic, singularities in cosmological models in general relativity. Using the calculus of tractors, we find conditions in terms of tractor curvature for a local extension of the conformal structure through a cosmological singularity and prove a local extension theorem along a congruence of timelike conformal geodesics.

  9. 40 CFR 52.2133 - General conformity.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false General conformity. 52.2133 Section 52...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) South Carolina § 52.2133 General conformity. The General Conformity regulations adopted into the South Carolina State Implementation Plan...

  10. 40 CFR 51.854 - Conformity analysis.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 2 2010-07-01 2010-07-01 false Conformity analysis. 51.854 Section 51... FOR PREPARATION, ADOPTION, AND SUBMITTAL OF IMPLEMENTATION PLANS Determining Conformity of General Federal Actions to State or Federal Implementation Plans § 51.854 Conformity analysis. Link to...

  11. 40 CFR 52.938 - General conformity.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false General conformity. 52.938 Section 52...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Kentucky § 52.938 General conformity. The General Conformity regulations were submitted on November 10, 1995, and adopted into the Kentucky...

  12. 40 CFR 52.2133 - General conformity.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 4 2011-07-01 2011-07-01 false General conformity. 52.2133 Section 52...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) South Carolina § 52.2133 General conformity. The General Conformity regulations adopted into the South Carolina State Implementation Plan...

  13. 40 CFR 52.799 - Transportation conformity.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 3 2011-07-01 2011-07-01 false Transportation conformity. 52.799... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Indiana § 52.799 Transportation conformity. On June 4, 2010, Indiana submitted the Transportation Conformity Consultation SIP consisting...

  14. 40 CFR 52.938 - General conformity.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 3 2011-07-01 2011-07-01 false General conformity. 52.938 Section 52...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Kentucky § 52.938 General conformity. The General Conformity regulations were submitted on November 10, 1995, and adopted into the Kentucky...

  15. Understanding conformal field theory through parafermions and Chern Simons theory

    SciTech Connect

    Hotes, S.A.

    1992-11-19

    Conformal field theories comprise a vast class of exactly solvable two dimensional quantum field theories. Conformal theories with an enlarged symmetry group, the current algebra symmetry, axe a key ingredient to possible string compactification models. The following work explores a Lagrangian approach to these theories. In the first part of this thesis, a large class of conformal theories, the so-called coset models, are derived semi-classically from a gauged version Of the Wess-Zumino-Witten functional. A non-local field transformation to the parafermionic field description is employed in the quantization procedure. Classically, these parafermionic fields satisfy non-trivial Poisson brackets, providing insight into the fractional spin nature of the conformal theory. The W-algebra symmetry is shown to appear naturally in this approach. In the second part of this thesis, the connection between the fusion algebra structure of Wess-Zumino-Witten models and the quantization of the Chern-Simons action on the torus is made explicit. The modular properties of the conformal model are also derived in this context, giving a natural demonstration of the Verlinde conjecture. The effects of background gauge fields and monopoles are also discussed.

  16. Exhaustive enumeration of protein conformations using experimental restraints.

    PubMed Central

    DeWitte, R. S.; Michnick, S. W.; Shakhnovich, E. I.

    1995-01-01

    We present an efficient new algorithm that enumerates all possible conformations of a protein that satisfy a given set of distance restraints. Rapid growth of all possible self-avoiding conformations on the diamond lattice provides construction of alpha-carbon representations of a protein fold. We investigated the dependence of the number of conformations on pairwise distance restraints for the proteins crambin, pancreatic trypsin inhibitor, and ubiquitin. Knowledge of between one and two contacts per monomer is shown to be sufficient to restrict the number of candidate structures to approximately 1,000 conformations. Pairwise RMS deviations of atomic position comparisons between pairs of these 1,000 structures revealed that these conformations can be grouped into about 25 families of structures. These results suggest a new approach to assessing alternative protein folds given a very limited number of distance restraints. Such restraints are available from several experimental techniques such as NMR, NOESY, energy transfer fluorescence spectroscopy, and crosslinking experiments. This work focuses on exhaustive enumeration of protein structures with emphasis on the possible use of NOESY-determined distance restraints. PMID:8528076

  17. Microwave Spectroscopy of Alkaloids: the Conformational Shapes of Nicotine

    NASA Astrophysics Data System (ADS)

    Grabow, Jens-Uwe; Mata, S.; López, J. C.; Peńa, I.; Cabezas, C.; Blanco, S.; Alonso, J. L.

    2010-06-01

    Nicotinoid alkaloids consist of two ring systems connected via a C-C σ-bond: Joining pyridine either with a (substituted) pyrrolidine or piperidine ring system, pyrrolidinic or piperidinic nicotinoids are formed. Nicotine itself, consisting of pyridine and N-methylpyrrolidine, is the prototype pyrrolidinic nicotinoid. Its coupled heteoaromatic and heteroaliphatic ring systems exhibit three sites that allow for conformational flexibility: (I) puckering of the pyrrolidine ring (Eq./Ax. positions of the pyridine), (II) inversion of the N-methyl group (Eq./Ax. positions of the hydrogen), and (III) relative orientation of the two rings (Syn-Anti). Two conformations of nicotine have been observed using the In-phase/quadrature-phase-Modulation Passage-Acquired-Coherence Technique (IMPACT) Fourier Transform Microwave (FTMW) spectrometer in Valladolid. The preferred conformations are characterized by an equatorial (Eq.) pyridine moiety and equatorial (Eq.) N-CH_3 stereochemistry. The planes of two rings are almost perpendicular with respect to each other while exhibiting two low energy conformations, Syn and Anti, that differ by a 180° rotation about the C-C σ-bond. The Eq.-Eq. conformational preference is likely due to a weak hydrogen bond interaction between the nitrogen lone pair at the N-methylpyrroline and the closest hydrogen in pyridine. Supporting quantum-chemical calculations are also provided. Lavrich, R. J.; Suenram, R. D.; Plusquellic, D. F.; Davis, S. 58th International Symposium on Molecular Spectroscopy, Columbus, OH 2003, RH13.

  18. Conformational profile of a proline-arginine hybrid

    PubMed Central

    Revilla-López, Guillermo; Jiménez, Ana I.; Cativiela, Carlos; Nussinov, Ruth; Alemán, Carlos; Zanuy, David

    2010-01-01

    The intrinsic conformational preferences of a new non-proteinogenic amino acid have been explored by computational methods. This tailored molecule, named (βPro)Arg, is conceived as a replacement for arginine in bioactive peptides when the stabilization of folded turn-like conformations is required. The new residue features a proline skeleton that bears the guanidilated side chain of arginine at the Cβ position of the five-membered pyrrolidine ring, either in a cis or a trans orientation with respect to the carboxylic acid. The conformational profile of the N-acetyl-N'-methylamide derivatives of the cis and trans isomers of (βPro)Arg has been examined in the gas phase and in solution by B3LYP/6–31+G(d,p) calculations and molecular dynamics simulations. The main conformational features of both isomers represent a balance between geometric restrictions imposed by the five-membered pyrrolidine ring and the ability of the guanidilated side chain to interact with the backbone through hydrogen-bonds. Thus, both cis and trans (βPro)Arg exhibit a preference for the αL conformation as a consequence of the interactions established between the guanidinium moiety and the main-chain amide groups. PMID:20886854

  19. Microwave Spectroscopy of Seven Conformers of 1,2-PROPANEDIOL

    NASA Astrophysics Data System (ADS)

    Neill, Justin L.; Muckle, Matt T.; Pate, Brooks H.; Lovas, F. J.; Plusquellic, D. F.; Remijan, A. J.

    2009-06-01

    Previously, two conformations of 1,2-propanediol have been identified by microwave spectroscopy by Caminati. Here we report the assignment of five additional conformers, two from work on a Balle-Flygare type cavity FTMW spectrometer at NIST, operating between 8 and 26 GHz, and three from a deep average scan on the chirped pulse Fourier transform microwave (CP-FTMW) spectrometer at the University of Virginia, operating between 6.5 and 18.5 GHz. All seven of the assigned conformers contain an intramolecular hydrogen bond between the two hydroxyl groups. Stark effect measurements have been performed on the cavity FTMW spectrometer to determine the dipole moments of the three lowest energy conformers. Relative abundances of the conformers have also been determined from the CP-FTMW spectrum. A subsequent interstellar search toward Sgr B2(N) yielded negative results with an upper limit to the total column density that is less than those of glycolaldehyde and ethylene glycol. W.Caminati, J. Mol. Spectrosc. 86 (1981) 193-201.

  20. Neural mechanisms underlying social conformity in an ultimatum game.

    PubMed

    Wei, Zhenyu; Zhao, Zhiying; Zheng, Yong

    2013-01-01

    When individuals' actions are incongruent with those of the group they belong to, they may change their initial behavior in order to conform to the group norm. This phenomenon is known as "social conformity." In the present study, we used event-related functional magnetic resonance imaging (fMRI) to investigate brain activity in response to group opinion during an ultimatum game. Results showed that participants changed their choices when these choices conflicted with the normative opinion of the group they were members of, especially in conditions of unfair treatment. The fMRI data revealed that a conflict with group norms activated the brain regions involved in norm violations and behavioral adjustment. Furthermore, in the reject-unfair condition, we observed that a conflict with group norms activated the medial frontal gyrus. These findings contribute to recent research examining neural mechanisms involved in detecting violations of social norms, and provide information regarding the neural representation of conformity behavior in an economic game.

  1. Effects of conformism on the cultural evolution of social behaviour.

    PubMed

    Molleman, Lucas; Pen, Ido; Weissing, Franz J

    2013-01-01

    Models of cultural evolution study how the distribution of cultural traits changes over time. The dynamics of cultural evolution strongly depends on the way these traits are transmitted between individuals by social learning. Two prominent forms of social learning are payoff-based learning (imitating others that have higher payoffs) and conformist learning (imitating locally common behaviours). How payoff-based and conformist learning affect the cultural evolution of cooperation is currently a matter of lively debate, but few studies systematically analyse the interplay of these forms of social learning. Here we perform such a study by investigating how the interaction of payoff-based and conformist learning affects the outcome of cultural evolution in three social contexts. First, we develop a simple argument that provides insights into how the outcome of cultural evolution will change when more and more conformist learning is added to payoff-based learning. In a social dilemma (e.g. a Prisoner's Dilemma), conformism can turn cooperation into a stable equilibrium; in an evasion game (e.g. a Hawk-Dove game or a Snowdrift game) conformism tends to destabilize the polymorphic equilibrium; and in a coordination game (e.g. a Stag Hunt game), conformism changes the basin of attraction of the two equilibria. Second, we analyse a stochastic event-based model, revealing that conformism increases the speed of cultural evolution towards pure equilibria. Individual-based simulations as well as the analysis of the diffusion approximation of the stochastic model by and large confirm our findings. Third, we investigate the effect of an increasing degree of conformism on cultural group selection in a group-structured population. We conclude that, in contrast to statements in the literature, conformism hinders rather than promotes the evolution of cooperation.

  2. Effects of Conformism on the Cultural Evolution of Social Behaviour

    PubMed Central

    Molleman, Lucas; Pen, Ido; Weissing, Franz J.

    2013-01-01

    Models of cultural evolution study how the distribution of cultural traits changes over time. The dynamics of cultural evolution strongly depends on the way these traits are transmitted between individuals by social learning. Two prominent forms of social learning are payoff-based learning (imitating others that have higher payoffs) and conformist learning (imitating locally common behaviours). How payoff-based and conformist learning affect the cultural evolution of cooperation is currently a matter of lively debate, but few studies systematically analyse the interplay of these forms of social learning. Here we perform such a study by investigating how the interaction of payoff-based and conformist learning affects the outcome of cultural evolution in three social contexts. First, we develop a simple argument that provides insights into how the outcome of cultural evolution will change when more and more conformist learning is added to payoff-based learning. In a social dilemma (e.g. a Prisoner’s Dilemma), conformism can turn cooperation into a stable equilibrium; in an evasion game (e.g. a Hawk-Dove game or a Snowdrift game) conformism tends to destabilize the polymorphic equilibrium; and in a coordination game (e.g. a Stag Hunt game), conformism changes the basin of attraction of the two equilibria. Second, we analyse a stochastic event-based model, revealing that conformism increases the speed of cultural evolution towards pure equilibria. Individual-based simulations as well as the analysis of the diffusion approximation of the stochastic model by and large confirm our findings. Third, we investigate the effect of an increasing degree of conformism on cultural group selection in a group-structured population. We conclude that, in contrast to statements in the literature, conformism hinders rather than promotes the evolution of cooperation. PMID:23874528

  3. Conformational transitions in random heteropolymer models

    NASA Astrophysics Data System (ADS)

    Blavatska, Viktoria; Janke, Wolfhard

    2014-01-01

    We study the conformational properties of heteropolymers containing two types of monomers A and B, modeled as self-attracting self-avoiding random walks on a regular lattice. Such a model can describe in particular the sequences of hydrophobic and hydrophilic residues in proteins [K. F. Lau and K. A. Dill, Macromolecules 22, 3986 (1989)] and polyampholytes with oppositely charged groups [Y. Kantor and M. Kardar, Europhys. Lett. 28, 169 (1994)]. Treating the sequences of the two types of monomers as quenched random variables, we provide a systematic analysis of possible generalizations of this model. To this end we apply the pruned-enriched Rosenbluth chain-growth algorithm, which allows us to obtain the phase diagrams of extended and compact states coexistence as function of both the temperature and fraction of A and B monomers along the heteropolymer chain.

  4. Conformation and chirality in liquid crystals

    NASA Astrophysics Data System (ADS)

    West, John L.; Zhao, Lei

    2013-09-01

    High helical twisting powerchiral additives are required for an expanding variety of liquid crystal displays and devices. Molecular conformation plays a critical role in determining the helical twisting power, HTP, of chiral additives. We studied additives based on an isosorbide benzoate ester core. Molecular modeling revealed two low energy states with very different conformations for this core The ultra-violet absorption and NMR spectra show two stable isosorbide conformers These spectra reveal how the relative populations of these two conformations change with temperature and how this is related to the helical twisting power. Conformation changes can explain many of the observed anomalous responses of HPT to temperature.

  5. An abbreviated tool for assessing feminine norm conformity: psychometric properties of the Conformity to Feminine Norms Inventory-45.

    PubMed

    Parent, Mike C; Moradi, Bonnie

    2011-12-01

    The Conformity to Feminine Norms Inventory-45 (CFNI-45; Parent & Moradi, 2010) is an important tool for assessing level of conformity to feminine gender norms and for investigating the implications of such norms for women's functioning. The authors of the present study assessed the factor structure, measurement invariance, reliability, and validity of the CFNI-45 with data from 520 college women (55% White). Confirmatory factor analyses with data from this sample suggested acceptable fit for the posited 9-factor structure. Furthermore, analyses of measurement invariance indicated similar structural properties with members of socioculturally dominant (i.e., White) and nondominant (i.e., women of color) racial/ethnic status groups. Also, subscales of the CFNI-45 demonstrated acceptable internal consistency reliability coefficients, and correlations with convergent and discriminant validity indicators supported the validity of subscales scores. Overall, results offered support for the CFNI-45 as a multidimensional measure of women's conformity to feminine norms. The CFNI-45 can be used in research to facilitate evaluation of the theorized roles of conformity to feminine norms in women's mental health, vocational behavior, interpersonal relationships, and other domains. The CFNI-45 can be used in clinical practice to assess and attend to clients' conformity to feminine norms as is called for in the American Psychological Association's (2007) Guidelines for Psychological Practice with Girls and Women.

  6. The biological bases of conformity.

    PubMed

    Morgan, T J H; Laland, K N

    2012-01-01

    Humans are characterized by an extreme dependence on culturally transmitted information and recent formal theory predicts that natural selection should favor adaptive learning strategies that facilitate effective copying and decision making. One strategy that has attracted particular attention is conformist transmission, defined as the disproportionately likely adoption of the most common variant. Conformity has historically been emphasized as significant in the social psychology literature, and recently there have also been reports of conformist behavior in non-human animals. However, mathematical analyses differ in how important and widespread they expect conformity to be, and relevant experimental work is scarce, and generates findings that are both mutually contradictory and inconsistent with the predictions of the models. We review the relevant literature considering the causation, function, history, and ontogeny of conformity, and describe a computer-based experiment on human subjects that we carried out in order to resolve ambiguities. We found that only when many demonstrators were available and subjects were uncertain was subject behavior conformist. A further analysis found that the underlying response to social information alone was generally conformist. Thus, our data are consistent with a conformist use of social information, but as subjects' behavior is the result of both social and asocial influences, the resultant behavior may not be conformist. We end by relating these findings to an embryonic cognitive neuroscience literature that has recently begun to explore the neural bases of social learning. Here conformist transmission may be a particularly useful case study, not only because there are well-defined and tractable opportunities to characterize the biological underpinnings of this form of social learning, but also because early findings imply that humans may possess specific cognitive adaptations for effective social learning.

  7. Gauge Choice in Conformal Gravity

    NASA Astrophysics Data System (ADS)

    Sultana, Joseph; Kazanas, Demosthenes

    2017-01-01

    In a recent paper (MNRAS 458, 4122 (2016)) K. Horne examined the effect of a conformally coupled scalar field (referred to as Higgs field) on the Mannheim-Kazanas metric gμν, i.e. the static spherically symmetric metric within the context of conformal gravity (CG), and studied its effect on the rotation curves of galaxies. He showed that for a Higgs field of the form S(r) = S0a/(r + a), where a is a radial length scale, the equivalent Higgs-frame Mannheim-Kazanas metric tilde{g}_{μ ν } = Ω ^2 g_{μ ν }, with Ω = S(r)/S0, lacks the linear γr term, which has been employed in the fitting of the galactic rotation curves without the need to invoke dark matter. In this brief note we point out that the representation of the Mannheim-Kazanas metric in a gauge where it lacks the linear term has already been presented by others, including Mannheim and Kazanas themselves, without the need to introduce a conformally coupled Higgs field. Furthermore, Horne argues that the absence of the linear term resolves the issue of light bending in the wrong direction, i.e. away from the gravitating mass, if γr > 0 in the Mannheim-Kazanas metric, a condition necessary to resolve the galactic dynamics in the absence of dark matter. In this case we also point out that the elimination of the linear term is not even required because the sign of the γr term in the metric can be easily reversed by a simple gauge transformation, and also that the effects of this term are indeed too small to be observed.

  8. Conformance Testing: Measurement Decision Rules

    NASA Technical Reports Server (NTRS)

    Mimbs, Scott M.

    2010-01-01

    The goal of a Quality Management System (QMS) as specified in ISO 9001 and AS9100 is to provide assurance to the customer that end products meet specifications. Measuring devices, often called measuring and test equipment (MTE), are used to provide the evidence of product conformity to specified requirements. Unfortunately, processes that employ MTE can become a weak link to the overall QMS if proper attention is not given to the measurement process design, capability, and implementation. Documented "decision rules" establish the requirements to ensure measurement processes provide the measurement data that supports the needs of the QMS. Measurement data are used to make the decisions that impact all areas of technology. Whether measurements support research, design, production, or maintenance, ensuring the data supports the decision is crucial. Measurement data quality can be critical to the resulting consequences of measurement-based decisions. Historically, most industries required simplistic, one-size-fits-all decision rules for measurements. One-size-fits-all rules in some cases are not rigorous enough to provide adequate measurement results, while in other cases are overly conservative and too costly to implement. Ideally, decision rules should be rigorous enough to match the criticality of the parameter being measured, while being flexible enough to be cost effective. The goal of a decision rule is to ensure that measurement processes provide data with a sufficient level of quality to support the decisions being made - no more, no less. This paper discusses the basic concepts of providing measurement-based evidence that end products meet specifications. Although relevant to all measurement-based conformance tests, the target audience is the MTE end-user, which is anyone using MTE other than calibration service providers. Topics include measurement fundamentals, the associated decision risks, verifying conformance to specifications, and basic measurement

  9. The Biological Bases of Conformity

    PubMed Central

    Morgan, T. J. H.; Laland, K. N.

    2012-01-01

    Humans are characterized by an extreme dependence on culturally transmitted information and recent formal theory predicts that natural selection should favor adaptive learning strategies that facilitate effective copying and decision making. One strategy that has attracted particular attention is conformist transmission, defined as the disproportionately likely adoption of the most common variant. Conformity has historically been emphasized as significant in the social psychology literature, and recently there have also been reports of conformist behavior in non-human animals. However, mathematical analyses differ in how important and widespread they expect conformity to be, and relevant experimental work is scarce, and generates findings that are both mutually contradictory and inconsistent with the predictions of the models. We review the relevant literature considering the causation, function, history, and ontogeny of conformity, and describe a computer-based experiment on human subjects that we carried out in order to resolve ambiguities. We found that only when many demonstrators were available and subjects were uncertain was subject behavior conformist. A further analysis found that the underlying response to social information alone was generally conformist. Thus, our data are consistent with a conformist use of social information, but as subjects’ behavior is the result of both social and asocial influences, the resultant behavior may not be conformist. We end by relating these findings to an embryonic cognitive neuroscience literature that has recently begun to explore the neural bases of social learning. Here conformist transmission may be a particularly useful case study, not only because there are well-defined and tractable opportunities to characterize the biological underpinnings of this form of social learning, but also because early findings imply that humans may possess specific cognitive adaptations for effective social learning. PMID:22712006

  10. Chromosome Conformation Capture in Drosophila.

    PubMed

    Li, Hua-Bing

    2016-01-01

    Linear chromatin fiber is packed inside the nuclei as a complex three-dimensional structure, and the organization of the chromatin has important roles in the appropriate spatial and temporal regulation of gene expression. To understand how chromatin organizes inside nuclei, and how regulatory proteins physically interact with genes, chromosome conformation capture (3C) technique provides a powerful and sensitive tool to detect both short- and long-range DNA-DNA interaction. Here I describe the 3C technique to detect the DNA-DNA interactions mediated by insulator proteins that are closely related to PcG in Drosophila, which is also broadly applicable to other systems.

  11. Conformational Transitions in Molecular Systems

    NASA Astrophysics Data System (ADS)

    Bachmann, M.; Janke, W.

    2008-11-01

    Proteins are the "work horses" in biological systems. In almost all functions specific proteins are involved. They control molecular transport processes, stabilize the cell structure, enzymatically catalyze chemical reactions; others act as molecular motors in the complex machinery of molecular synthetization processes. Due to their significance, misfolds and malfunctions of proteins typically entail disastrous diseases, such as Alzheimer's disease and bovine spongiform encephalopathy (BSE). Therefore, the understanding of the trinity of amino acid composition, geometric structure, and biological function is one of the most essential challenges for the natural sciences. Here, we glance at conformational transitions accompanying the structure formation in protein folding processes.

  12. Toward TeV Conformality

    SciTech Connect

    Appelquist, T; Avakian, A; Babich, R; Brower, R C; Cheng, M; Clark, M A; Cohen, S D; Fleming, G T; Kiskis, J; Neil, E T; Osborn, J C; Rebbi, C; Schaich, D; Soltz, R; Vranas, P

    2009-11-30

    We study the chiral condensate <{bar {psi}}{psi}> for an SU(3) gauge theory with N{sub f} massless Dirac fermions in the fundamental representation when N{sub f} is increased from 2 to 6. For N{sub f} = 2, our lattice simulations of <{bar {psi}}{psi}>/F{sup 3}, where F is the Nambu-Goldstone-boson decay constant, agree with the measured QCD value. For N{sub f} = 6, this ratio shows significant enhancement, presaging an even larger enhancement anticipated as N{sub f} increases further, toward the critical value for transition from confinement to infrared conformality.

  13. From conformal to Einstein gravity

    NASA Astrophysics Data System (ADS)

    Anastasiou, Giorgos; Olea, Rodrigo

    2016-10-01

    We provide a simple derivation of the equivalence between Einstein and conformal gravity (CG) with Neumann boundary conditions given by Maldacena. As Einstein spacetimes are Bach flat, a generic solution to CG would contain both Einstein and non-Einstein parts. Using this decomposition of the spacetime curvature in the Weyl tensor makes manifest the equivalence between the two theories, both at the level of the action and the variation of it. As a consequence, we show that the on-shell action for critical gravity in four dimensions is given uniquely in terms of the Bach tensor.

  14. Conformational isomers of linear rotaxanes

    NASA Astrophysics Data System (ADS)

    Sevick, Edith M.; Williams, David R. M.

    2014-09-01

    We examine a simple model of rotaxane structure, with 3 asymmetric rings interacting via repulsive power-law forces. This interlocked molecule exhibits conformational isomerisation which is different from that of molecules whose connectedness is through covalent bonds. The rings are free to translate along and rotate around the axle, and hence weak interaction forces between the rings can lead to distinct rotamer states. We use energy minimisation to determine these states exactly, and show that there can be transitions from asymmetric to symmetric states by varying the bond lengths. We also use classical statistical mechanics to show the effect of thermal noise.

  15. Molecular dynamics study of 2rotaxanes: influence of solvation and cation on co-conformation.

    PubMed

    Fradera, Xavier; Márquez, Manuel; Smith, Bradley D; Orozco, Modesto; Luque, F Javier

    2003-06-13

    The conformational preference of a [2]rotaxane system has been examined by molecular dynamics simulations. The rotaxane wheel consists of two bridged binding components: a cis-dibenzo-18-crown-6 ether and a 1,3-phenyldicarboxamide, and the penetrating axle consists of a central isophthaloyl unit with phenyltrityl capping groups. The influence of solvation on the co-conformation of the [2]rotaxane was evaluated by comparing the conformational flexibility in two solvents: chloroform and dimethyl sulfoxide. Attention was also paid to the effect of cation binding on the dynamical properties of the [2]rotaxane. The conformational stability of the [2]rotaxane was calculated using a MM/PB-SA strategy, and the occurrence of specific motions was examined by essential dynamics analysis. The changes in the co-conformational properties in the two solvents and upon cation binding are discussed in light of the available NMR data. The results indicate that in chloroform solution the [2]rotaxane system exists as a mixture of co-conformational states including some that have hydrogen bonds between axle C=O and wheel NH groups. Analysis of the simulations allow us to hypothesize that the [2]rotaxane's circumrotation motion can occur as the result of a dynamic process that combines a preliminary axle sliding step that breaks these hydrogen bonds and a conformational change in the ester group more distant from the wheel. In contrast, no hydrogen-bonded co-conformation was found in dimethyl sulfoxide, which appears to be due to the preferential formation of hydrogen bonds between the wheel NH groups with solvent molecules. Moreover, the axle experiences notable changes in anisotropic shielding, which would explain why the NMR signals are broadened in this solvent. Insertion of a sodium cation into the crown ether reduces co-conformational flexibility due to an interaction of the axle with the cation. Overall, the results reveal how both solvent and ionic atmosphere can influence the co-conformational

  16. Tetrazole acetic acid: Tautomers, conformers, and isomerization

    SciTech Connect

    Araujo-Andrade, C.; Reva, I. Fausto, R.

    2014-02-14

    Monomers of (tetrazol-5-yl)-acetic acid (TAA) were obtained by sublimation of the crystalline compound and the resulting vapors were isolated in cryogenic nitrogen matrices at 13 K. The conformational and tautomeric composition of TAA in the matrix was characterized by infrared spectroscopy and vibrational calculations carried out at the B3LYP/6-311++G(d,p) level. TAA may adopt two tautomeric modifications, 1H- and 2H-, depending on the position of the annular hydrogen atom. Two-dimensional potential energy surfaces (PESs) of TAA were theoretically calculated at the MP2/6-311++G(d,p) level, for each tautomer. Four and six symmetry-unique minima were located on these PESs, for 1H- and 2H-TAA, respectively. The energetics of the detected minima was subsequently refined by calculations at the QCISD level. Two 1H- and three 2H-conformers fall within the 0–8 kJ mol{sup −1} energy range and should be appreciably populated at the sublimation temperature (∼330 K). Observation of only one conformer for each tautomer (1ccc and 2pcc) is explained in terms of calculated barriers to conformational rearrangements. All conformers with the cis O=COH moiety are separated by low barriers (less than 10 kJ mol{sup −1}) and collapse to the most stable 1ccc (1H-) and 2pcc (2H-) forms during deposition of the matrix. On the trans O=COH surfaces, the relative energies are very high (between 12 and 27 kJ mol{sup −1}). The trans forms are not thermally populated at the sublimation conditions and were not detected in matrices. One high-energy form in each tautomer, 1cct (1H-) and 2pct (2H-), was found to differ from the most stable form only by rotation of the OH group and separated from other forms by high barriers. This opened a perspective for their stabilization in a matrix. 1cct and 2pct were generated in the matrices selectively by means of narrow-band near-infrared (NIR) irradiations of the samples at 6920 and 6937 cm{sup −1}, where the first OH stretching overtone

  17. 76 FR 63575 - Transportation Conformity Rule: MOVES Regional Grace Period Extension

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-13

    ... CONTACT: Meg Patulski, State Measures and Conformity Group, Transportation and Regional Programs Division...; fax number: (734) 214-4052; e- mail address: patulski.meg@epa.gov ; or Astrid Larsen, State...

  18. 76 FR 63554 - Transportation Conformity Rule: MOVES Regional Grace Period Extension

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-13

    ... INFORMATION CONTACT: Meg Patulski, State Measures and Conformity Group, Transportation and Regional Programs...: (734) 214-4842; fax number: (734) 214-4052; e- mail address: patulski.meg@epa.gov ; or Astrid...

  19. A hhase I/II trial to evaluate three-dimensional conformal radiation therapy confined to the region of the lumpectomy cavity for Stage I/II breast carcinoma: Initial report of feasibility and reproducibility of Radiation Therapy Oncology Group (RTOG) Study 0319

    SciTech Connect

    Vicini, Frank . E-mail: fvicini@beaumont.edu; Winter, Kathryn M.S.; Straube, William; Wong, John; Pass, Helen; Rabinovitch, Rachel; Chafe, Susan; Arthur, Douglas; Petersen, Ivy; McCormick, Beryl

    2005-12-01

    Background: This prospective study (Radiation Therapy Oncology Group Study 0319) examines the use of three-dimensional conformal external beam radiation therapy to deliver accelerated partial breast irradiation. Reproducibility, as measured by technical feasibility, was the primary end point with the goal of demonstrating whether the technique is widely applicable in a multicenter setting before a Phase III trial is undertaken. Methods and Materials: This study was designed such that if fewer than 5 cases out of the first 42 patients evaluable were scored as unacceptable, the treatment would be considered reproducible. Patients received 38.5 Gy in 3.85 Gy/fraction delivered twice daily. The clinical target volume included the lumpectomy cavity plus a 10-15-mm margin bounded by 5 mm within the skin surface and the lung-chest wall interface. The planning target volume (PTV) included the clinical target volume plus a 10-mm margin. Treatment plans were judged as follows: (1) No variations (total coverage), 95% isodose surface covers 100% of the PTV and all specified critical normal tissue dose-volume histogram (DVH) limits met. (2) Minor variation (marginal coverage), 95% isodose surface covers between {>=}95% and <100% of the PTV. No portion of PTV receives <93% of prescription (isocenter) dose. All specified critical normal tissue DVH limits fall within 5% of the guidelines. (3) Major variation (miss), 95% isodose surface covers <95% of the PTV. Portion of PTV receives <93% of prescription isocenter dose. Any critical normal tissue DVH limit exceeds 5% of the specified value. Results: A total of 58 patients were enrolled on this study between 8/15/03 and 4/30/04, 5 of whom were ineligible or did not receive protocol treatment. Two additional patients were excluded, one because the on-study form was not submitted, and the other because no treatment planning material was submitted. This primary end point analysis is based on the first 42 (out of 51) evaluable patients

  20. Improving Group Processes in Transdisciplinary Case Studies for Sustainability Learning

    ERIC Educational Resources Information Center

    Hansmann, Ralf; Crott, Helmut W.; Mieg, Harald A.; Scholz, Roland W.

    2009-01-01

    Purpose: Deficient group processes such as conformity pressure can lead to inadequate group decisions with negative social, economic, or environmental consequences. The study aims to investigate how a group technique (called INFO) improves students' handling of conformity pressure and their collective judgments in the context of a…

  1. Coexisting stable conformations of gaseous protein ions.

    PubMed Central

    Suckau, D; Shi, Y; Beu, S C; Senko, M W; Quinn, J P; Wampler, F M; McLafferty, F W

    1993-01-01

    For further insight into the role of solvent in protein conformer stabilization, the structural and dynamic properties of protein ions in vacuo have been probed by hydrogen-deuterium exchange in a Fourier-transform mass spectrometer. Multiply charged ions generated by electrospray ionization of five proteins show exchange reactions with 2H2O at 10(-7) torr (1 torr = 133.3 Pa) exhibiting pseudo-first-order kinetics. Gas-phase compactness of the S-S cross-linked RNase A relative to denatured S-derivatized RNase A is indicated by exchange of 35 and 135 hydrogen atoms, respectively. For pure cytochrome c ions, the existence of at least three distinct gaseous conformers is indicated by the substantially different values--52, 113, and 74--of reactive H atoms; the observation of these same values for ions of a number--2, 7, and 5, respectively--of different charge states indicates conformational insensitivity to coulombic forces. For each of these conformers, the compactness in vacuo indicated by these values corresponds directly to that of a known conformer structure in the solution from which the conformer ions are produced by electrospray. S-derivatized RNase A ions also exist as at least two gaseous conformers exchanging 50-140 H atoms. Gaseous conformer ions are isometrically stable for hours; removal of solvent greatly increases conformational rigidity. More specific ion-molecule reactions could provide further details of conformer structures. Images PMID:8381533

  2. Generative Models of Conformational Dynamics

    PubMed Central

    Langmead, Christopher James

    2014-01-01

    Atomistic simulations of the conformational dynamics of proteins can be performed using either Molecular Dynamics or Monte Carlo procedures. The ensembles of three-dimensional structures produced during simulation can be analyzed in a number of ways to elucidate the thermodynamic and kinetic properties of the system. The goal of this chapter is to review both traditional and emerging methods for learning generative models from atomistic simulation data. Here, the term ‘generative’ refers to a model of the joint probability distribution over the behaviors of the constituent atoms. In the context of molecular modeling, generative models reveal the correlation structure between the atoms, and may be used to predict how the system will respond to structural perturbations. We begin by discussing traditional methods, which produce multivariate Gaussian models. We then discuss GAMELAN (GrAphical Models of Energy LANdscapes), which produces generative models of complex, non-Gaussian conformational dynamics (e.g., allostery, binding, folding, etc) from long timescale simulation data. PMID:24446358

  3. Minimal realization of ℓ-conformal Galilei algebra, Pais-Uhlenbeck oscillators and their deformation

    NASA Astrophysics Data System (ADS)

    Krivonos, Sergey; Lechtenfeld, Olaf; Sorin, Alexander

    2016-10-01

    We present the minimal realization of the ℓ-conformal Galilei group in 2+1 dimensions on a single complex field. The simplest Lagrangians yield the complex PaisUhlenbeck oscillator equations. We introduce a minimal deformation of the ℓ = 1/2 conformal Galilei (a.k.a. Schrödinger) algebra and construct the corresponding invariant actions. Based on a new realization of the d = 1 conformal group, we find a massive extension of the near-horizon Kerr-dS/AdS metric.

  4. Surface control of alkyl chain conformations and 2D chiral amplification.

    PubMed

    Hauptmann, Nadine; Scheil, Katharina; Gopakumar, Thiruvancheril G; Otte, Franziska L; Schütt, Christian; Herges, Rainer; Berndt, Richard

    2013-06-19

    Trioctyl-functionalized triazatriangulenium (trioctyl-TATA) deposited on Au(111) and Ag(111) surfaces by electrospray ionization was investigated using low-temperature scanning tunneling microscopy. The molecule surprisingly adsorbs with gauche rather than anti conformations of the octyl groups. We observed chiral amplification in the islands. Only one of the eight possible configurations of the octyl groups was found in homochiral hexagonal networks. Quantum-chemical calculations confirmed and explained the preference for the gauche conformations of adsorbed trioctyl-TATA.

  5. Protein conformational populations and functionally relevant substates.

    PubMed

    Ramanathan, Arvind; Savol, Andrej; Burger, Virginia; Chennubhotla, Chakra S; Agarwal, Pratul K

    2014-01-21

    Functioning proteins do not remain fixed in a unique structure, but instead they sample a range of conformations facilitated by motions within the protein. Even in the native state, a protein exists as a collection of interconverting conformations driven by thermodynamic fluctuations. Motions on the fast time scale allow a protein to sample conformations in the nearby area of its conformational landscape, while motions on slower time scales give it access to conformations in distal areas of the landscape. Emerging evidence indicates that protein landscapes contain conformational substates with dynamic and structural features that support the designated function of the protein. Nuclear magnetic resonance (NMR) experiments provide information about conformational ensembles of proteins. X-ray crystallography allows researchers to identify the most populated states along the landscape, and computational simulations give atom-level information about the conformational substates of different proteins. This ability to characterize and obtain quantitative information about the conformational substates and the populations of proteins within them is allowing researchers to better understand the relationship between protein structure and dynamics and the mechanisms of protein function. In this Account, we discuss recent developments and challenges in the characterization of functionally relevant conformational populations and substates of proteins. In some enzymes, the sampling of functionally relevant conformational substates is connected to promoting the overall mechanism of catalysis. For example, the conformational landscape of the enzyme dihydrofolate reductase has multiple substates, which facilitate the binding and the release of the cofactor and substrate and catalyze the hydride transfer. For the enzyme cyclophilin A, computational simulations reveal that the long time scale conformational fluctuations enable the enzyme to access conformational substates that allow

  6. Assessment of Group Preferences and Group Uncertainty for Decision Making

    DTIC Science & Technology

    1976-06-01

    inhibiting group problem solving. In order to effectively use interacting groups , methods need to be found that minimize the inhibiting influences ... pressure for conformity , and so forth, while the use of controlled feedback on successive rounds allows the exchange of ideas and information. A typic.al...methods depend on strLuctured conmunication to allow the facilitation of group judgments while avoiding many of the detrimental influences that have

  7. Conformal regularization of Einstein's field equations

    NASA Astrophysics Data System (ADS)

    Röhr, Niklas; Uggla, Claes

    2005-09-01

    To study asymptotic structures, we regularize Einstein's field equations by means of conformal transformations. The conformal factor is chosen so that it carries a dimensional scale that captures crucial asymptotic features. By choosing a conformal orthonormal frame, we obtain a coupled system of differential equations for a set of dimensionless variables, associated with the conformal dimensionless metric, where the variables describe ratios with respect to the chosen asymptotic scale structure. As examples, we describe some explicit choices of conformal factors and coordinates appropriate for the situation of a timelike congruence approaching a singularity. One choice is shown to just slightly modify the so-called Hubble-normalized approach, and one leads to dimensionless first-order symmetric hyperbolic equations. We also discuss differences and similarities with other conformal approaches in the literature, as regards, e.g., isotropic singularities.

  8. On the conformation of the propranolol molecule

    NASA Astrophysics Data System (ADS)

    Sadlej-Sosnowska, N.; Dobrowolski, J. Cz; Mazurek, A. P.

    2000-03-01

    The structure of the propranolol molecule has been optimized within the AM1 and PM3 semiempirical framework followed by ab initio HF/6-31G ∗ refinement. On each calculation level the conformational space was sampled to search for the lowest-energy conformer(s) from among a few hundreds of conformers at the semiempirical step and next from among a few dozens of conformers at the ab initio level. Finally, five stable conformers were found; each stabilized by one or two of the three possible hydrogen bonds. The geometrical and electronic parameters were established and found to differ only slightly in the structures with the hydrogen bond either present or not.

  9. Playing nice: a multi-methodological study on the effects of social conformity on memory

    PubMed Central

    Deuker, Lorena; Müller, Anna R.; Montag, Christian; Markett, Sebastian; Reuter, Martin; Fell, Juergen; Trautner, Peter; Axmacher, Nikolai

    2013-01-01

    Conformity is an important aspect of social behavior. Two main motives have been identified: people may adapt their behavior to “play nice” despite knowing better (normative conformity) or they may accept the others' opinion as a valid source of information (informative conformity). Neuroimaging studies can help to distinguish between these two possibilities. Here, we present a functional magnetic resonance imaging (fMRI) study on memory conformity in a real group situation. We investigated the effects of group pressure on activity in hippocampus and anterior cingulate cortex (ACC) which likely support informative and normative memory conformity, respectively. Furthermore, we related the single nucleotide polymorphism (SNP) rs4680 [called Catechol-O-methyltransferase (COMT) Val158Met] on the gene coding for COMT to both behavior and fMRI activation. Homozygous Met-allele carriers (Val−) behaved more conformist than carriers of at least one Val-allele (Val+). In the neuroimaging data, we compared trials in which subjects were confronted with a majority of incorrect group responses to trials in which they were confronted with a majority of correct group responses. We found increased hippocampal activity when the majority of the group was correct, possibly indicating retrieval processes. Moreover, we observed enhanced activity in the ACC when the majority of the group was incorrect, suggesting that conformity was mostly normative. Most interestingly, this latter effect was more pronounced for Val− as compared to Val+ participants. This offers a speculative explanation for the higher behavioral levels of social conformity in Val− allele carriers, because their subjectively perceived conflict in the presence of an incorrect group majority may have been higher. Overall, this study demonstrates how the mechanisms leading to complex social behavior such as conformity can be studied by combining genetic analyses and fMRI in social neuroscience paradigms. PMID

  10. Playing nice: a multi-methodological study on the effects of social conformity on memory.

    PubMed

    Deuker, Lorena; Müller, Anna R; Montag, Christian; Markett, Sebastian; Reuter, Martin; Fell, Juergen; Trautner, Peter; Axmacher, Nikolai

    2013-01-01

    Conformity is an important aspect of social behavior. Two main motives have been identified: people may adapt their behavior to "play nice" despite knowing better (normative conformity) or they may accept the others' opinion as a valid source of information (informative conformity). Neuroimaging studies can help to distinguish between these two possibilities. Here, we present a functional magnetic resonance imaging (fMRI) study on memory conformity in a real group situation. We investigated the effects of group pressure on activity in hippocampus and anterior cingulate cortex (ACC) which likely support informative and normative memory conformity, respectively. Furthermore, we related the single nucleotide polymorphism (SNP) rs4680 [called Catechol-O-methyltransferase (COMT) Val158Met] on the gene coding for COMT to both behavior and fMRI activation. Homozygous Met-allele carriers (Val-) behaved more conformist than carriers of at least one Val-allele (Val+). In the neuroimaging data, we compared trials in which subjects were confronted with a majority of incorrect group responses to trials in which they were confronted with a majority of correct group responses. We found increased hippocampal activity when the majority of the group was correct, possibly indicating retrieval processes. Moreover, we observed enhanced activity in the ACC when the majority of the group was incorrect, suggesting that conformity was mostly normative. Most interestingly, this latter effect was more pronounced for Val- as compared to Val+ participants. This offers a speculative explanation for the higher behavioral levels of social conformity in Val- allele carriers, because their subjectively perceived conflict in the presence of an incorrect group majority may have been higher. Overall, this study demonstrates how the mechanisms leading to complex social behavior such as conformity can be studied by combining genetic analyses and fMRI in social neuroscience paradigms.

  11. Scattering Via Conformal Higher Spin Exchanges

    NASA Astrophysics Data System (ADS)

    Tseytlin, A. A.

    We consider a model of massless scalars interacting (via bilinear conserved currents) with conformal higher spin fields in flat space. We compute the tree-level four-scalar scattering amplitude using a natural prescription for summation over an infinite set of conformal higher spin exchanges and find that it vanishes. Independently, we show that the vanishing of the scalar scattering amplitude is, in fact, implied by the global conformal higher spin symmetry of this model.

  12. Conformal Electromagnetic Particle in Cell: A Review

    SciTech Connect

    Meierbachtol, Collin S.; Greenwood, Andrew D.; Verboncoeur, John P.; Shanker, Balasubramaniam

    2015-10-26

    We review conformal (or body-fitted) electromagnetic particle-in-cell (EM-PIC) numerical solution schemes. Included is a chronological history of relevant particle physics algorithms often employed in these conformal simulations. We also provide brief mathematical descriptions of particle-tracking algorithms and current weighting schemes, along with a brief summary of major time-dependent electromagnetic solution methods. Several research areas are also highlighted for recommended future development of new conformal EM-PIC methods.

  13. Solution conformational study of Scyliorhinin I analogues with conformational constraints by two-dimensional NMR and theoretical conformational analysis.

    PubMed

    Rodziewicz-Motowidło, S; Legowska, A; Qi, X F; Czaplewski, C; Liwo, A; Sowiński, P; Mozga, W; Olczak, J; Zabrocki, J; Rolka, K

    2000-09-01

    Two analogues of Scyliorhinin I (Scyl), a tachykinin with N-MeLeu in position 8 and a 1,5-disubstituted tetrazole ring between positions 7 and 8, introduced in order to generate local conformational constraints, were synthesized using the solid-phase method. Conformational studies in water and DMSO-d6 were performed on these peptides using a combination of the two-dimensional NMR technique and theoretical conformational analysis. The algorithm of conformational search consisted of the following three stages: (i) extensive global conformational analysis in order to find all low-energy conformations; (ii) calculation of the NOE effects and vicinal coupling constants for each of the low energy conformations; (iii) determining the statistical weights of these conformations by means of a nonlinear least-squares procedure, in order to obtain the best fit of the averaged simulated spectrum to the experimental one. In both solvents the three-dimensional structure of the analogues studied can be interpreted only in terms of an ensemble of multiple conformations. For [MeLeu8]Scyl, the C-terminal 6-10 fragment adopts more rigid structure than the N-terminal one. In the case of the analogue with the tetrazole ring in DMSO-d6 the three-dimensional structure is characterized by two dominant conformers with similar geometry of their backbones. They superimpose especially well (RMSD = 0.28 A) in the 6-9 fragments. All conformers calculated in both solvents superimpose in their C-terminal fragments much better than those of the first analogue. The results obtained indicate that the introduction of the tetrazole ring into the Scyl molecule rigidifies its structure significantly more than that of MeLeu.

  14. Conformity in condylar replacement knee prosthesis.

    PubMed

    Walker, P S; Hsieh, H H

    1977-05-01

    Experiments were carried out to determine the optimum conformity between the femoral and tibial condyles in condylar replacement knee prostheses. Wear tests and observations from removed prostheses indicated that both high and low conformity produced characteristic abrasion and fatigue. Partly conforming condyles provided stability under load-bearing but allowed laxity to occur. Fixation to resist the various forces on the tibial components was enhanced by a short central intramedullary peg. Partial conformity is proposed as the optimum configuration between femoral and tibial components.

  15. Rotational Spectroscopy Unveils Eleven Conformers of Adrenaline

    NASA Astrophysics Data System (ADS)

    Cabezas, C.; Cortijo, V.; Mata, S.; Lopez, J. C.; Alonso, J. L.

    2013-06-01

    Recent improvements in our LA-MB-FTMW instrumentation have allowed the characterization of eleven and eight conformers for the neurotransmitters adrenaline and noradrenaline respectively. The observation of this rich conformational behavior is in accordance with the recent observation of seven conformers for dopamine and in sharp contrast with the conformational reduction proposed for catecholamines. C. Cabezas, I. Peña, J. C. López, J. L. Alonso J. Phys. Chem. Lett. 2013, 4, 486. H. Mitsuda, M. Miyazaki, I. B. Nielsen, P. Carcabal,C. Dedonder, C. Jouvet, S. Ishiuchi, M. Fujii J. Phys. Chem. Lett. 2010, 1, 1130.

  16. Evolutionary Conserved Positions Define Protein Conformational Diversity

    PubMed Central

    Saldaño, Tadeo E.; Monzon, Alexander M.; Parisi, Gustavo; Fernandez-Alberti, Sebastian

    2016-01-01

    Conformational diversity of the native state plays a central role in modulating protein function. The selection paradigm sustains that different ligands shift the conformational equilibrium through their binding to highest-affinity conformers. Intramolecular vibrational dynamics associated to each conformation should guarantee conformational transitions, which due to its importance, could possibly be associated with evolutionary conserved traits. Normal mode analysis, based on a coarse-grained model of the protein, can provide the required information to explore these features. Herein, we present a novel procedure to identify key positions sustaining the conformational diversity associated to ligand binding. The method is applied to an adequate refined dataset of 188 paired protein structures in their bound and unbound forms. Firstly, normal modes most involved in the conformational change are selected according to their corresponding overlap with structural distortions introduced by ligand binding. The subspace defined by these modes is used to analyze the effect of simulated point mutations on preserving the conformational diversity of the protein. We find a negative correlation between the effects of mutations on these normal mode subspaces associated to ligand-binding and position-specific evolutionary conservations obtained from multiple sequence-structure alignments. Positions whose mutations are found to alter the most these subspaces are defined as key positions, that is, dynamically important residues that mediate the ligand-binding conformational change. These positions are shown to be evolutionary conserved, mostly buried aliphatic residues localized in regular structural regions of the protein like β-sheets and α-helix. PMID:27008419

  17. Proline Conformation in a Functional Tau Fragment.

    PubMed

    Ahuja, Puneet; Cantrelle, François-Xavier; Huvent, Isabelle; Hanoulle, Xavier; Lopez, Juan; Smet, Caroline; Wieruszeski, Jean-Michel; Landrieu, Isabelle; Lippens, G

    2016-01-16

    The conformational state of distinct prolines can determine the folding of a protein but equally other biological processes when coupled to a conformation-sensitive secondary reaction. For the neuronal tau protein, the importance of proline conformation is underscored by its interaction with different prolyl cis/trans isomerases. The proline conformation would gain even further importance after phosphorylation of the preceding residue by various proline-directed kinases. A number of molecular diseases including Alzheimer's disease and traumatic brain injury were thereby recently qualified as "cistauosis", as they would imply a cis conformation for the pThr231-Pro232 prolyl bond. We here investigate by NMR spectroscopy the conformation of all prolines in a functional Tau fragment, Tau[208-324]. Although we can detect and identify some minor conformers in the cis form, we show that all prolines are for over 90% in the trans conformation. Phosphorylation by CDK2/CycA3, which notably leads to complete modification of the Thr231 residue, does not change this conclusion. Our data hence disagree with the notion that specific prolyl bonds in tau would adopt preferentially the cis conformation.

  18. Conformable eddy current array delivery

    NASA Astrophysics Data System (ADS)

    Summan, Rahul; Pierce, Gareth; Macleod, Charles; Mineo, Carmelo; Riise, Jonathan; Morozov, Maxim; Dobie, Gordon; Bolton, Gary; Raude, Angélique; Dalpé, Colombe; Braumann, Johannes

    2016-02-01

    The external surface of stainless steel containers used for the interim storage of nuclear material may be subject to Atmospherically Induced Stress Corrosion Cracking (AISCC). The inspection of such containers poses a significant challenge due to the large quantities involved; therefore, automating the inspection process is of considerable interest. This paper reports upon a proof-of-concept project concerning the automated NDT of a set of test containers containing artificially generated AISCCs. An Eddy current array probe with a conformable padded surface from Eddyfi was used as the NDT sensor and end effector on a KUKA KR5 arc HW robot. A kinematically valid cylindrical raster scan path was designed using the KUKA|PRC path planning software. Custom software was then written to interface measurement acquisition from the Eddyfi hardware with the motion control of the robot. Preliminary results and analysis are presented from scanning two canisters.

  19. Conformal frame dependence of inflation

    SciTech Connect

    Domènech, Guillem; Sasaki, Misao E-mail: misao@yukawa.kyoto-u.ac.jp

    2015-04-01

    Physical equivalence between different conformal frames in scalar-tensor theory of gravity is a known fact. However, assuming that matter minimally couples to the metric of a particular frame, which we call the matter Jordan frame, the matter point of view of the universe may vary from frame to frame. Thus, there is a clear distinction between gravitational sector (curvature and scalar field) and matter sector. In this paper, focusing on a simple power-law inflation model in the Einstein frame, two examples are considered; a super-inflationary and a bouncing universe Jordan frames. Then we consider a spectator curvaton minimally coupled to a Jordan frame, and compute its contribution to the curvature perturbation power spectrum. In these specific examples, we find a blue tilt at short scales for the super-inflationary case, and a blue tilt at large scales for the bouncing case.

  20. Conformational properties of penicillins: quantum chemical calculations and molecular dynamics simulations of benzylpenicillin.

    PubMed

    Díaz, Natalia; Suárez, Dimas; Sordo, Tomás L

    2003-11-30

    Herein, we present theoretical results on the conformational properties of benzylpenicillin, which are characterized by means of quantum chemical calculations (MP2/6-31G* and B3LYP/6-31G*) and classical molecular dynamics simulations (5 ns) both in the gas phase and in aqueous solution. In the gas phase, the benzylpenicillin conformer in which the thiazolidine ring has the carboxylate group oriented axially is the most favored one. Both intramolecular CH. O and dispersion interactions contribute to stabilize the axial conformer with respect to the equatorial one. In aqueous solution, a molecular dynamics simulation predicts a relative population of the axial:equatorial conformers of 0.70:0.30 in consonance with NMR experimental data. Overall, the quantum chemical calculations as well as the simulations give insight into substituent effects, the conformational dynamics of benzylpenicillin, the frequency of ring-puckering motions, and the correlation of side chain and ring-puckering motions.

  1. Conformation equilibrium of 3-(hydroxymethyl)piperidine in solvents with different polarity

    NASA Astrophysics Data System (ADS)

    Korneichuk, A. Ya.; Senyavin, V. M.; Kuramshina, G. M.

    2017-02-01

    Quantum-chemical calculations of the 3-(hydroxymethyl)piperidine molecule conformers were performed at the B3LYP/6-31+G** level of theory, and four most stable conformations with different relative orientation of CH2OH and N-H groups were determined. The optimized structures, vibration frequencies, and band intensities in the spectra of the conformers were obtained. The conformational equilibria of the most stable rotational isomers in solvents of different polarity was studied within the polarizable continuum model. According to the results of calculations, the conformational equilibrium in solution is substantially changed on varying the solvent polarity. This conclusion was confirmed by comparison with IR absorption spectra of 3-(hydroxymethyl)piperidine solutions in carbon tetrachloride in the region of OH-stretchings.

  2. An Expression of Periodic Phenomena of Fashion on Sexual Selection Model with Conformity Genes and Memes

    NASA Astrophysics Data System (ADS)

    Mutoh, Atsuko; Tokuhara, Shinya; Kanoh, Masayoshi; Oboshi, Tamon; Kato, Shohei; Itoh, Hidenori

    It is generally thought that living things have trends in their preferences. The mechanism of occurrence of another trends in successive periods is concerned in their conformity. According to social impact theory, the minority is always exists in the group. There is a possibility that the minority make the transition to the majority by conforming agents. Because of agent's promotion of their conform actions, the majority can make the transition. We proposed an evolutionary model with both genes and memes, and elucidated the interaction between genes and memes on sexual selection. In this paper, we propose an agent model for sexual selection imported the concept of conformity. Using this model we try an environment where male agents and female agents are existed, we find that periodic phenomena of fashion are expressed. And we report the influence of conformity and differentiation on the transition of their preferences.

  3. Necessary Condition for Emergent Symmetry from the Conformal Bootstrap.

    PubMed

    Nakayama, Yu; Ohtsuki, Tomoki

    2016-09-23

    We use the conformal bootstrap program to derive the necessary conditions for emergent symmetry enhancement from discrete symmetry (e.g., Z_{n}) to continuous symmetry [e.g., U(1)] under the renormalization group flow. In three dimensions, in order for Z_{2} symmetry to be enhanced to U(1) symmetry, the conformal bootstrap program predicts that the scaling dimension of the order parameter field at the infrared conformal fixed point must satisfy Δ_{1}>1.08. We also obtain the similar necessary conditions for Z_{3} symmetry with Δ_{1}>0.580 and Z_{4} symmetry with Δ_{1}>0.504 from the simultaneous conformal bootstrap analysis of multiple four-point functions. As applications, we show that our necessary conditions impose severe constraints on the nature of the chiral phase transition in QCD, the deconfinement criticality in Néel valence bond solid transitions, and anisotropic deformations in critical O(n) models. We prove that some fixed points proposed in the literature are unstable under the perturbation that cannot be forbidden by the discrete symmetry. In these situations, the second-order phase transition with enhanced symmetry cannot happen.

  4. Conformational Preferences of α-Substituted Proline Analogues

    PubMed Central

    Flores-Ortega, Alejandra; Jiménez, Ana I.; Cativiela, Carlos; Nussinov, Ruth; Alemán, Carlos; Casanovas, Jordi

    2009-01-01

    DFT calculations at the B3LYP/6-31+G(d,p) level have been used to investigate how the replacement of the α hydrogen by a more sterically demanding group affects the conformational preferences of proline. Specifically, the N-acetyl-N’-methylamide derivatives of L-proline, L-α-methylproline and L-α-phenylproline have been calculated, with both the cis/trans isomerism of the peptide bonds and the puckering of the pyrrolidine ring being considered. The effects of solvation have been evaluated using a Self Consistent Reaction Field model. As expected, tetrasubstitution at the α carbon destabilizes the conformers with one or more peptide bonds arranged in cis. The lowest energy minimum has been found to be identical for the three compounds investigated, but important differences are observed regarding other energetically accessible backbone conformations. The results obtained provide evidence that the distinct steric requirements of the substituent at Cα may play a significant role in modulating the conformational preferences of proline. PMID:18351745

  5. Conformal invariance, dynamical dark energy and the CMB

    SciTech Connect

    Mottola, Emil

    2010-01-01

    Einstein's General Relativity receives quantum corrections relevant at cosmological distance scales. These effects arise from conformal scalar degrees of freedom in the extended Effective Field Theory (EFT) of gravity required by the trace anomaly of the quantum stress tensor in curved space. Scalar degrees of freedom in cosmology arise naturally from the effective action of the trace anomaly in the Standard Model, without the ad hoc introduction of an inflaton field. In the EFT including the trace anomaly terms, {Lambda}{sub eff} becomes dynamical and potentially dependent upon both space and time. The fluctuations of these anomaly scalars may also influence the spectrum and statistics of the Cosmic Microwave Background (CMB). Under the hypothesis that scale invariance should be promoted to full conformal invariance, an hypothesis supported by the embedding of the conformal group of three dimensional flat sections in de Sitter space, the form of the CMB bi-spectrum can be fixed, and the tri-spectrum constrained. The angular spectra predicted by conformal invariance differ from those suggested by simple models of inflation.

  6. Conformity Scores Differentiate Older Hemodialyzed Patients and Patients with Continuous Peritoneal Dialysis.

    PubMed

    Nowak, Zbigniew; Laudanski, Krzysztof

    2016-11-25

    BACKGROUND Conformity is a psychological variable related to the propensity of an individual to match his or her behavior and opinion to the perceived social and cultural norm, even if these do not represent the true beliefs of the person. The aim of the present study was to investigate whether the psychological variable of conformity is different in two distinct modes of renal replacement therapy (RRT) in end-stage renal disease (ESRD). MATERIAL AND METHODS A total of 56 hemodialyzed patients (HD group), 45 continuous ambulatory peritoneal dialysis patients (CAPD group) and 62 healthy volunteers (CONTR group) were enrolled in the study. The Social Appraisal Questionnaire (SAQ) was employed, and chart review was performed to collect clinical data. RESULTS When age was not a factor, the conformity measure was significantly higher in the HD group compared with the CAPD and CONTR groups. The lowest conformity was found in healthy participants who were asked to imagine an acute medical problem. The highest conformity was found in older HD and CAPD patients. CONCLUSIONS Being chronically ill and having adaptable views may be more favorable traits for coping with ESRD in dialyzed patients, especially in elderly HD patients. On the other hand, conformity can be deleterious if CAPD patients decide to overlook certain facts or not confront the medical aspects of their condition.

  7. Conformity Scores Differentiate Older Hemodialyzed Patients and Patients with Continuous Peritoneal Dialysis

    PubMed Central

    Nowak, Zbigniew; Laudanski, Krzysztof

    2016-01-01

    Background Conformity is a psychological variable related to the propensity of an individual to match his or her behavior and opinion to the perceived social and cultural norm, even if these do not represent the true beliefs of the person. The aim of the present study was to investigate whether the psychological variable of conformity is different in two distinct modes of renal replacement therapy (RRT) in end-stage renal disease (ESRD). Material/Methods A total of 56 hemodialyzed patients (HD group), 45 continuous ambulatory peritoneal dialysis patients (CAPD group) and 62 healthy volunteers (CONTR group) were enrolled in the study. The Social Appraisal Questionnaire (SAQ) was employed, and chart review was performed to collect clinical data. Results When age was not a factor, the conformity measure was significantly higher in the HD group compared with the CAPD and CONTR groups. The lowest conformity was found in healthy participants who were asked to imagine an acute medical problem. The highest conformity was found in older HD and CAPD patients. Conclusions Being chronically ill and having adaptable views may be more favorable traits for coping with ESRD in dialyzed patients, especially in elderly HD patients. On the other hand, conformity can be deleterious if CAPD patients decide to overlook certain facts or not confront the medical aspects of their condition. PMID:27886156

  8. Conformational Changes in 5-Methoxyindole: Effects of Thermal, Vibrational and Electronic Excitations.

    PubMed

    Lopes Jesus, António Jorge; Fausto, Rui; Reva, Igor

    2017-04-14

    The molecule of 5-methoxyindole (5MOI) may adopt two conformational states, syn and anti, with respect to the relative orientation of the NH and OCH3 groups. Structure of monomeric 5MOI was characterized spectroscopically, in mid- and near-infrared domains. The conformational composition of 5MOI could be controlled in three different ways. Thermally, two conformers of 5MOI could be trapped in xenon matrixes at 16 K. Upon annealing the xenon matrix to temperatures about 30-40 K, the higher energy syn form converted to the ground state anti conformer. Vibrational excitations in the near-infrared domain, at the frequency of the first NH stretching overtone, 6853 cm-1, afforded the inverse conformational transformation, and a part of the anti conformer was upconverted to the syn form. Electronic excitations in the UV-domain, at 315-310 nm, resulted in a total consumption of the syn form again, in favor of anti. Upon further irradiations at 308 nm, a partial repopulation of the syn form, at the expense of anti, was observed. We propose a mechanistic explanation of the observed transformations, which is based on the computations of the vibrational spectra of the two conformers, and also on computations of the ground state S0 and the first excited state S1 potential energy surfaces along the coordinate for conformational isomerization. The highlights of the present work are: the first experimental observation of the minor syn conformer of 5MOI; evidence of the long-range vibrational energy transfer resulting in conformational isomerization upon excitation of the NH stretching overtone; possibility of partial conformational control of 5MOI by using electronic excitations.

  9. Peak deconvolution in high-field asymmetric waveform ion mobility spectrometry (FAIMS) to characterize macromolecular conformations

    NASA Astrophysics Data System (ADS)

    Robinson, Errol W.; Sellon, Rachel E.; Williams, Evan R.

    2007-01-01

    Protonated poly(ethylene glycol), produced by electrospray ionization (ESI), with molecular weights ranging from 0.3 to 5 kDa and charge states from 1+ to 7+ were characterized using high-field asymmetric waveform ion mobility spectrometry (FAIMS). Results for all but some of the 3+ and 4+ charge states are consistent with a single gas-phase conformer or family of unresolved conformers for each of these charge states. The FAIMS compensation voltage scans resulted in peaks that could be accurately fit with a single Gaussian for each peak. The peak widths increase linearly with compensation voltage for maximum ion transmission but do not depend on m/z or molecular weight. Fitting parameters obtained from the poly(ethylene glycol) data were used to analyze conformations of oxidized and reduced lysozyme formed from different solutions. For oxidized lysozyme formed from a buffered aqueous solution, a single conformer (or group of unresolved conformers) was observed for the 7+ and 8+ charge states. Two conformers were observed for the 9+ and 10+ charge states formed from more denaturing solutions. Data for the fully reduced form indicate the existence of up to three different conformers for each charge state produced directly by ESI and a general progression from a more extended to a more folded structure with decreasing charge state. These results are consistent with those obtained previously by proton-transfer reactivity and drift tube ion mobility experiments, although more conformers were identified for the fully reduced form of lysozyme using FAIMS.

  10. A model of protein conformational substates

    PubMed Central

    Stein, D. L.

    1985-01-01

    Many proteins have been observed to exist in a large number of conformations that are believed to play an important role in their dynamics. A model of protein conformational substates that incorporates the ideas of frustration and disorder in analogy to glasses and spin glasses is proposed. Applications to x-ray diffraction, Mössbauer studies, and recombination experiments are discussed. PMID:16593568

  11. Conformational Sampling of Peptides in Cellular Environments☆

    PubMed Central

    Tanizaki, Seiichiro; Clifford, Jacob; Connelly, Brian D.; Feig, Michael

    2008-01-01

    Abstract Biological systems provide a complex environment that can be understood in terms of its dielectric properties. High concentrations of macromolecules and cosolvents effectively reduce the dielectric constant of cellular environments, thereby affecting the conformational sampling of biomolecules. To examine this effect in more detail, the conformational preference of alanine dipeptide, poly-alanine, and melittin in different dielectric environments is studied with computer simulations based on recently developed generalized Born methodology. Results from these simulations suggest that extended conformations are favored over α-helical conformations at the dipeptide level at and below dielectric constants of 5–10. Furthermore, lower-dielectric environments begin to significantly stabilize helical structures in poly-alanine at ɛ = 20. In the more complex peptide melittin, different dielectric environments shift the equilibrium between two main conformations: a nearly fully extended helix that is most stable in low dielectrics and a compact, V-shaped conformation consisting of two helices that is preferred in higher dielectric environments. An additional conformation is only found to be significantly populated at intermediate dielectric constants. Good agreement with previous studies of different peptides in specific, less-polar solvent environments, suggest that helix stabilization and shifts in conformational preferences in such environments are primarily due to a reduced dielectric environment rather than specific molecular details. The findings presented here make predictions of how peptide sampling may be altered in dense cellular environments with reduced dielectric response. PMID:17905846

  12. Regulatory Conformance Checking: Logic and Logical Form

    ERIC Educational Resources Information Center

    Dinesh, Nikhil

    2010-01-01

    We consider the problem of checking whether an organization conforms to a body of regulation. Conformance is studied in a runtime verification setting. The regulation is translated to a logic, from which we synthesize monitors. The monitors are evaluated as the state of an organization evolves over time, raising an alarm if a violation is…

  13. Starkweather Social Conformity Test for Preschool Children.

    ERIC Educational Resources Information Center

    Starkweather, Elizabeth K.

    The Starkweather Social Conformity Test is a research instrument designed to measure conforming and nonconforming behavior by providing the young child with opportunities to make choices in a situation in which he can follow a model or respond freely according to his own preferences. The test discriminates between compulsive conformists or…

  14. Conformational analysis of thiophene analogs of propranolol

    NASA Astrophysics Data System (ADS)

    Corral, Carlos; Donoso, Rosa; Elguero, Jose; Goya, Pilar; Lissavetzky, Jaime; Rozas, Isabel

    1990-10-01

    Conformation of 3-tert-butylamino-1-thienyloxy-2-propanol, a thiophene analogue of propanolol, have been theoretically investigated by molecular mechanics and semiempirical calculations. The conformational minima obtained have been compared with those reported for propranolol using molecular graphics. The good "fit" obtained can account for the similar biological activity of these compounds.

  15. Performance of Conformable Ablators in Aerothermal Environments

    NASA Technical Reports Server (NTRS)

    Thornton, J.; Fan, W.; Skokova, K.; Stackpoole, M.; Beck, R.; Chavez-Garcia, J.

    2012-01-01

    Conformable Phenolic Impregnated Carbon Ablator, a cousin of Phenolic Impregnated Carbon Ablator (PICA), was developed at NASA Ames Research Center as a lightweight thermal protection system under the Fundamental Aeronautics Program. PICA is made using a brittle carbon substrate, which has a very low strain to failure. Conformable PICA is made using a flexible carbon substrate, a felt in this case. The flexible felt significantly increases the strain to failure of the ablator. PICA is limited by its thermal mechanical properties. Future NASA missions will require heatshields that are more fracture resistant than PICA and, as a result, NASA Ames is working to improve PICAs performance by developing conformable PICA to meet these needs. Research efforts include tailoring the chemistry of conformable PICA with varying amounts of additives to enhance mechanical properties and testing them in aerothermal environments. This poster shows the performance of conformable PICA variants in arc jets tests. Some mechanical and thermal properties will also be presented.

  16. Nucleosome structure and conformational changes

    SciTech Connect

    McGhee, J.D.; Felsenfeld, G.; Eisenberg, H.

    1980-10-01

    We have used a variety of chemical probes to measure the accessibility of DNA on the surface of the nucleosome. We review these results, and describe new experiments which show that T4 phage DNA can form complexes with the core histones, possessing the properties of normal nucleosomes. Since T4 DNA is largely occupied by glucose residues in the major groove, this suggests that the major groove is not filled with histone amino acid side chains. We also report results of recent measurements which appear to show that only a few strong charge interactions are involved in the attachment of the terminal 20 nucleotide pairs at each end of nucleosome core DNA. We speculate on the possible functional significance of the accessibility of DNA revealed by all of these experiments. We have also examined conformational changes induced in nucleosomes at high ionic strength (0.5 to 0.7M NaCl). The frictional coefficient is found to undergo a small increase in this region, not consistent with models in which the nucleosome is completely unfolded, but possibly reflecting the dissociation of terminal DNA from the nucleosome surface.

  17. Conforming Morse-Smale Complexes

    SciTech Connect

    Gyulassy, Attila; Gunther, David; Levine, Joshua A.; Tierny, Julien; Pascucci, Valerio

    2014-08-11

    Morse-Smale (MS) complexes have been gaining popularity as a tool for feature-driven data analysis and visualization. However, the quality of their geometric embedding and the sole dependence on the input scalar field data can limit their applicability when expressing application-dependent features. In this paper we introduce a new combinatorial technique to compute an MS complex that conforms to both an input scalar field and an additional, prior segmentation of the domain. The segmentation constrains the MS complex computation guaranteeing that boundaries in the segmentation are captured as separatrices of the MS complex. We demonstrate the utility and versatility of our approach with two applications. First, we use streamline integration to determine numerically computed basins/mountains and use the resulting segmentation as an input to our algorithm. This strategy enables the incorporation of prior flow path knowledge, effectively resulting in an MS complex that is as geometrically accurate as the employed numerical integration. Our second use case is motivated by the observation that often the data itself does not explicitly contain features known to be present by a domain expert. We introduce edit operations for MS complexes so that a user can directly modify their features while maintaining all the advantages of a robust topology-based representation.

  18. Cosmology in Conformally Flat Spacetime

    NASA Astrophysics Data System (ADS)

    Endean, Geoffrey

    1997-04-01

    A possible solution to cosmological age and redshift-distance difficulties has recently been proposed by applying the appropriate conformally flat spacetime (CFS) coordinates to the standard solution of the field equations in a standard dust model closed universe. Here it is shown that CFS time correctly measures the true age of the universe, thus answering a major theoretical objection to the proposal. It is also shown that the CFS interpretation leads to a strong Copernican principle and is in all other respects wholly self-consistent. The deceleration parameter q0 is related to t0, the present age of the universe divided by L, the scale length of its curvature (an absolute constant). The values of q0 and L are approximately 5/6 and 9.2 × 109 yr, respectively. It is shown that the universe started everywhere simultaneously, with no recession velocity until the effects of its closed topology became significant. Conclusions to the contrary in standard theory (the big bang) stem from a different definition of recession velocity. The theoretical present cosmological mass density is quantified as 4.4 × 10-27 kg m-3 approximately, thus greatly reducing, in a closed universe, the observational requirement to find hidden mass. It is also shown that the prediction of standard theory, for a closed universe, of collapse toward a big crunch termination, will not in fact take place.

  19. Miniaturization techniques benefit conformal arrays

    NASA Astrophysics Data System (ADS)

    Chuang, C. A.; Martin, D. J.; Moldovan, N.

    1984-03-01

    Crucial design tools for lightweight conformal arrays include low-loss, lightweight microstrip elements and substrates, the optimization of fabrication methods, and the design of the radome. It is noted that all these have demonstrated their effectiveness in the design of an S-band receive array. This new receive array comprises the radiation aperture, substrate, feed, and bonding skins. A circular microstrip patch is chosen as the lightweight radiation element owing to its small size and well-known performance characteristics. It is noted that honeycomb materials with bonding skins have proven to be excellent substrates for these elements. A honeycomb substrate material made up of a uniform lattice of circular cells extruded from a polycarbonate thermoplastic resin forms the element, which typically weighs less than 4 oz. per square foot. This honeycomb possesses good RF properties and affords very high resistance to rain and hail impact without sacrificing electrical performance. The design of the array grid is optimized by considering the effects of grating lobes, sidelobes, and the expected scanning performance.

  20. Conformational flexibility in biochemical regulation

    SciTech Connect

    Trewhella, J.

    1993-09-01

    Small-angle X-ray and neutron scattering have proven extremely useful for studying the evolutionarily related dumbbell-shaped Ca {sup 2+} -binding proteins calmodulin and troponin C and their interactions with the target proteins whose activity they regulate. Calmodulin contracts about target enzyme binding domains with the common characteristic of having a high propensity for forming a basic, amphipathic a-helix. The contraction is achieved via flexibility in the interconnecting helix region of the molecule that links its two globular domains. This flexibility allows calmodulin to optimize its binding to different arrangements of hydrophobic and charged residues important in forming these complexes. In contrast calmodulin remains extended in its interaction with the catalytic subunit of phosphorylase kinase. There are structural and functional similarities between this interaction and that of troponin C and troponin I. Our most recent neutron scattering experiments confirm our prediction that troponin C also remains extended in this complex. The ability of the dumbbell-shaped Ca {sup 2+} -binding proteins to modulate their conformations via flexibility in the interconnecting helix region in order to accommodate different target binding domains is a remarkable example nature building functional diversity as well as specificity into a compact and unusual shape.

  1. Holography of the conformal window

    NASA Astrophysics Data System (ADS)

    Alvares, Raul; Evans, Nick; Kim, Keun-Young

    2012-07-01

    Inspired by the model of Jarvinen and Kiritsis, we present a simple holographic model for the onset of chiral symmetry breaking at the edge of the conformal window in QCD in the Veneziano limit. Our most naive model enforces the QCD two-loop running coupling on a D3/D7 holographic brane system. The mass of the holographic field, describing the chiral condensate in the model, is driven below the Breitenlohner-Freedman bound when the running is sufficiently strong, triggering chiral symmetry breaking for Nf/Nc<2.9. This model though contains too great a remnant of supersymmetry and does not correctly encode the perturbative anomalous dimensions of QCD. In a second model we impose the QCD anomalous dimension result and find chiral symmetry breaking sets in for Nf/Nc=4 at a Berezinsky-Kosterlitz-Thouless-type phase transition. In this case the transition is triggered when the anomalous dimension of the mass operator γm=1.

  2. SU-E-T-538: Lung SBRT Dosimetric Comparison of 3D Conformal and RapidArc Planning

    SciTech Connect

    Jiang, R; Zhan, L; Osei, E

    2015-06-15

    Purpose: Dose distributions of RapidArc Plan can be quite different from standard 3D conformal radiation therapy. SBRT plans can be optimized with high conformity or mimic the 3D conformal treatment planning with very high dose in the center of the tumor. This study quantifies the dosimetric differences among 3D conformal plan; flattened beam and FFF beam RapidArc Plans for lung SBRT. Methods: Five lung cancer patients treated with 3D non-coplanar SBRT were randomly selected. All the patients were CT scanned with 4DCT to determine the internal target volume. Abdominal compression was applied to minimize respiratory motion for SBRT patients. The prescription dose was 48 Gy in 4 fractions. The PTV coverage was optimized by two groups of objective function: one with high conformity, another mimicking 3D conformal dose distribution with high dose in the center of PTV. Optimization constraints were set to meet the criteria of the RTOG-0915 protocol. All VMAT plans were optimized with the RapidArc technique using four full arcs in Eclipse treatment planning system. The RapidArc SBRT plans with flattened 6MV beam and 6MV FFF beam were generated and dosimetric results were compared with the previous treated 3D non-coplanar plans. Results: All the RapidArc plans with flattened beam and FFF beam had similar results for the PTV and OARs. For the high conformity optimization group, The DVH of PTV exhibited a steep dose fall-off outside the PTV compared to the 3D non-coplanar plan. However, for the group mimicking the 3D conformal target dose distribution, although the PTV is very similar to the 3D conformal plan, the ITV coverage is better than 3D conformal plan. Conclusion: Due to excellent clinical experiences of 3D conformal SBRT treatment, the Rapid Arc optimization mimicking 3D conformal planning may be suggested for clinical use.

  3. Conformations of Trimethyl Phosphite: a Matrix Isolation Infrared and AB Initio Study

    NASA Astrophysics Data System (ADS)

    Ramanathan, N.; Sundararajan, K.; Kar, Bishnu Prasad; Viswanathan, K. S.

    2011-06-01

    Hyperconjugative interactions have received considerable attention because of its importance in determining structure and reactivity in organic compounds. In all these molecules, our studies, as many others in the literature, indicated that the O-P-O and O-C-O segments played a crucial role in conformational preferences. In the case of the organic phosphates, in addition to the O-P-O segments, the P=O group was also found to influence the structures. To address this issue further, it was thought interesting to study the conformations of trimethylphosphite (TMPhite), which lacks a P=O group. A comparison of the conformations of trimethylphosphate (TMP) and TMPhite was expected to highlight the role of the P=O group in the conformational preference of organic phosphates, which is the motivation for the present work. The conformations of TMPhite were studied using matrix isolation infrared spectroscopy. TMPhite was trapped in a nitrogen matrix using an effusive source maintained at 298 K and 410 K and also a supersonic source. These experiments were designed to enable us to assign the infrared features of the higher energy conformer(s). As a result of these experiments, infrared spectra of the conformations of TMPhite were obtained. The experimental studies were supported by ab initio computations performed at the B3LYP/6-31++G** level. Computations indicated four minima corresponding to conformers with the following symmetries: C_1, C_s, C1a and C_3, given in order of increasing energy. This conformational picture was clearly different from that of TMP, in which the C_3 was the lowest energy structure, thereby clearly indicating the role of the P=O group in structural preferences in these systems. We also performed a photochemical insertion of oxygen in TMPhite to produce TMP in the matrix, in an effort to correlate the conformers of the two molecules. These experiments also gave rise to interesting side reactions, where in addition to TMP, we also observed the

  4. Shear-induced conformation change in α-crystalline nylon6

    SciTech Connect

    Arabnejad, Saeid; Manzhos, Sergei; Shim, V. P. W.; He, Chaobin

    2014-12-01

    A study of shear deformation of α-crystalline nylon6 is undertaken, using dispersion-corrected density functional theory. The shear stress-strain relationship and shear strength for interlayer shear deformation are computed. A conformation change induced by shear is identified along twinning deformation, whereby the conformation of chains, specifically the location of non-H-bonded hydrogen atoms, changes continuously. This paves a way for the modulation of properties of this group of materials by small shear deformation, if the non-H-bonded hydrogens are chemically substituted to form non-equivalent conformations when deformed.

  5. 47 CFR 2.1072 - Limitation on Declaration of Conformity.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Limitation on Declaration of Conformity. 2.1072... Conformity § 2.1072 Limitation on Declaration of Conformity. (a) The Declaration of Conformity signifies that...'s rules. (b) A Declaration of Conformity by the responsible party is effective until a...

  6. Perceived Symbols of Authority and Their Influence on Conformity.

    ERIC Educational Resources Information Center

    Bushman, Brad J.

    Although there are many variables that influence conformity, Bickman (1974) found that the apparel of the person making a request had a significant influence on conformity. To evaluate other factorswhicn may influence conformity (gender, age, status of the conforming subject, and altruism in conforming), 150 adult pedestrians (45% female, 71%…

  7. High-Dose Conformal Radiotherapy for Patients With Stage III Non-Small-Cell Lung Carcinoma

    SciTech Connect

    Nakayama, Hidetsugu; Satoh, Hiroaki; Kurishima, Koichi; Ishikawa, Hiroichi; Tokuuye, Koichi

    2010-11-01

    Purpose: To determine the effectiveness of high-dose conformal radiotherapy to the involved field for patients with Stage III non-small-cell lung cancer (NSCLC). Methods and Materials: Between May 1999 and April 2006, a total of 100 consecutive patients with inoperable Stage IIIA or IIIB NSCLC with a performance score of 0 to 2 and treatment by radical radiotherapy combined with chemotherapy were included. Up to August 2002, 33 patients underwent conventional radiotherapy of 56 Gy to 66 Gy using anteroposterior opposite ports to the primary tumor and elective lymph nodes (conventional group). After September 2002, the remaining 67 patients underwent high-dose radiotherapy of 66 Gy to 84 Gy to the involved volume with three-dimensional (3-D) conformal radiotherapy (conformal group). Results: The median survival was 13.2 months (95% confidence interval [CI], 7.5-18.5 months) in the conventional group and 17.3 months (95% CI, 10.7- 24.0 months) in the conformal group. The overall survival at 3 years were 9.1% (95% CI, -0.7-18.9%) in the conventional group and 31.0% (95% CI, 18.9-43.1%) in the conformal group; the conformal group had a significantly better overall survival (p < 0.05). The radiotherapy method (hazard ratio = 0.55, p < 0.05) and performance status (hazard ratio = 1.48, p < 0.05) were shown to be statistically significant independent prognostic factors. Conclusions: Based on the practical experience reported here, 3-D conformal radiotherapy allowed dose escalation without excessive toxicity, and may improve overall survival rates for patients with Stage III NSCLC.

  8. The Detrimental Effects of Oxytocin-Induced Conformity on Dishonesty in Competition.

    PubMed

    Aydogan, Gökhan; Jobst, Andrea; D'Ardenne, Kimberlee; Müller, Norbert; Kocher, Martin G

    2017-04-01

    Justifications may promote unethical behavior because they constitute a convenient loophole through which people can gain from immoral behavior and preserve a positive self-image at the same time. A justification that is widely used is rooted in conformity: Unethical choices become more permissible because one's peers are expected to make the same unethical choices. In the current study, we tested whether an exogenous alteration of conformity led to a lower inclination to adhere to a widely accepted norm (i.e., honesty) under the pressure of competition. We took advantage of the well-known effects of intranasally applied oxytocin on affiliation, in-group conformity, and in-group favoritism in humans. We found that conformity was enhanced by oxytocin, and this enhancement had a detrimental effect on honesty in a competitive environment but not in a noncompetitive environment. Our findings contribute to recent evidence showing that competition may lead to unethical behavior and erode moral values.

  9. C-metric solution for conformal gravity with a conformally coupled scalar field

    NASA Astrophysics Data System (ADS)

    Meng, Kun; Zhao, Liu

    2017-02-01

    The C-metric solution of conformal gravity with a conformally coupled scalar field is presented. The solution belongs to the class of Petrov type D spacetimes and is conformal to the standard AdS C-metric appeared in vacuum Einstein gravity. For all parameter ranges, we identify some of the physically interesting static regions and the corresponding coordinate ranges. The solution may contain a black hole event horizon, an acceleration horizon, either of which may be cut by the conformal infinity or be hidden behind the conformal infinity. Since the model is conformally invariant, we also discussed the possible effects of the conformal gauge choices on the structure of the spacetime.

  10. Euclidean M-theory background dual to a three-dimensional scale-invariant field theory without conformal invariance

    NASA Astrophysics Data System (ADS)

    Nakayama, Yu

    2017-02-01

    We show that 11-dimensional supergravity in Euclidean signature admits an exact classical solution with isometry corresponding to a three-dimensional scale-invariant field theory without conformal invariance. We also construct the holographic renormalization group flow that connects the known UV conformal fixed point and the new scale-invariant but not conformal fixed point. In view of holography, the existence of such classical solutions suggests that the topologically twisted M2-brane gauge theory possesses a scale-invariant but not conformal phase.

  11. Plasma Amino Acid Coatings for a Conformal Growth of Titania Nanoparticles

    DTIC Science & Technology

    2010-04-01

    Dayton, Ohio 45433-7702 ABSTRACT We report on the conformal synthesis of ultrathin films from the aminoacid histidine on flat silicon substrates and...nanoparticles (28–31). Additionally, histidine aminoacids with their high concentra- tion of amine groups are considered to be potential precur- sors for...report on the conformal synthesis of ultrathin films from the aminoacid histidine on flat silicon substrates and 3D periodic polymer structures via

  12. Design, Conformation, and Crystallography of 2-Naphthyl Phenyl Ethers as Potent Anti-HIV Agents

    SciTech Connect

    Lee, Won-Gil; Chan, Albert H.; Spasov, Krasimir A.; Anderson, Karen S.; Jorgensen, William L.

    2016-12-08

    Catechol diethers that incorporate a 7-cyano-2-naphthyl substituent are reported as non-nucleoside inhibitors of HIV-1 reverse transcriptase (NNRTIs). Many of the compounds have 1–10 nM potencies toward wild-type HIV-1. An interesting conformational effect allows two unique conformers for the naphthyl group in complexes with HIV-RT. X-ray crystal structures for 4a and 4f illustrate the alternatives.

  13. Controlling Protein Conformations to Explore Unprecedented Material Properties by Single-Molecule Surgery

    DTIC Science & Technology

    2012-08-17

    Molecule Protein Conformational Dynamics in Enzymatic Reactions,” Single-Molecule Biophysics Meeting, Aspen , CO, Jan. 4-10, 2009. H. P. Lu, “Single...Donor-Acceptor: Cy3-Cy5) pair labeled HPPK molecule tethered between a glass cover-slip surface and a handle (biotin group plus streptavidin), and a...5, 2008. H. P. Lu, “Probing Single-Molecule Protein Conformational Dynamics in Enzymatic Reactions,” Single-Molecule Biophysics Meeting, Aspen

  14. Conformational Dynamics in DNA Replication Selectivity

    NASA Astrophysics Data System (ADS)

    Brieba, Luis G.

    2007-11-01

    Replicative DNA polymerases are remarkable molecular machines that carry out DNA synthesis accordingly to the Watson and Crick rules (Guanine pairs with Cytosine and Adenine with Thymidine) with high specificity or fidelity. The biochemical mechanism that dictates polymerase fidelity has its fundaments in the tight active site of replicative polymerases and the shape and size of the Watson-Crick base pairs. Pre-steady state kinetic analysis have shown that during polymerase nucleotide addition, the chemical reaction is not the rate limiting step and it was postulated that DNA polymerases suffer a conformational change from an "open" to a "closed" conformation before chemistry which is also the step responsible for their high fidelity. Crystal structures of replicative DNA polymerases demonstrated that the fingers subdomain suffers a large conformational change during catalysis and that this conformational transition aligns the polymerase active site in a proper conformation for catalysis. Recent studies using single molecule techniques and Fluorescence Resonance Energy Transfer analysis also shown that at least in the case of T7 DNA polymerase, the closure of the fingers subdomain is in part the rate limiting step associated with the high fidelity of DNA polymerases, although the overall fidelity of the reaction maybe involves an assemble of chemical steps and several conformational changes. Our current knowledge indicates that the mechanisms of enzyme specificity in DNA replication involve several energy landscapes that maybe correlated with conformational changes and active site assemblies.

  15. Stable phantom-energy wormholes admitting conformal motions

    NASA Astrophysics Data System (ADS)

    Kuhfittig, Peter K. F.

    It has been argued that wormholes are as good a prediction of Einstein’s theory as black holes but the theoretical construction requires a reverse strategy, specifying the desired geometric properties of the wormhole and leaving open the determination of the stress-energy tensor. We begin by confirming an earlier result by the author showing that a complete wormhole solution can be obtained by adopting the equation of state p = ωρ and assuming that the wormhole admits a one-parameter group of conformal motions. The main purpose of this paper is to use the assumption of conformal symmetry to show that the wormhole is stable to linearized radial perturbations whenever ‑ 1.5 < ω < ‑1.

  16. Fluoroolefins as peptide mimetics. 2. A computational study of the conformational ramifications of peptide bond replacement.

    PubMed

    McKinney, Brian E; Urban, Joseph J

    2010-01-21

    The design of peptide mimetic compounds is greatly facilitated by the identification of functionalities that can act as peptide replacements. The fluoroalkene moiety has recently been employed for that purpose. The purpose of this work is to examine the conformational ramifications of replacing peptide bonds with fluoroalkene moieties, thus generating peptidomimetics. The alanine dipeptide analogue (ADA) was chosen as a model compound. Three peptidomimetic systems were investigated including one generated by replacement of both peptide bonds of ADA, designated as DFA, and those generated by the single replacement of the C-terminal peptide bond and N-terminal peptide bond, designated as CFA and NFA, respectively. Conformations for all three systems were generated by exhaustive Monte Carlo searching. Relative conformational energies were calculated at the MP2/aug-cc-pVTZ/MP2/aug-cc-pVDZ (for DFA), MP2/-aug-cc-pVTZ//MP2/6-311+G(d,p), B3LYP/6-31+G(d)//B3LYP/6-31+G(d), and MMFF levels of theory. Aqueous phase conformational preferences were determined through calculations making use of continuum hydration models. The results indicate that replacement of both peptide bonds of ADA generates a peptidomimetic with conformational preferences where extended conformations are favored and the conformational profile is relatively insensitive to the nature of the surrounding medium. This is in contrast to ADA where the conformational preferences depend highly on the surrounding medium and where folded conformations with intramolecular hydrogen bonds are important in the absence of an interacting solvent. CFA and NFA are found to exhibit conformational preferences that do in some ways more closely resemble those of the alanine dipeptide analogue. This is particularly true in the case of NFA where interactions between the NH and CF groups are reminiscent of the intramolecular hydrogen bonding possible in ADA.

  17. Comparative Incidence of Conformational, Neurodegenerative Disorders

    PubMed Central

    de Pedro-Cuesta, Jesús; Rábano, Alberto; Martínez-Martín, Pablo; Ruiz-Tovar, María; Alcalde-Cabero, Enrique; Almazán-Isla, Javier; Avellanal, Fuencisla; Calero, Miguel

    2015-01-01

    Background The purpose of this study was to identify incidence and survival patterns in conformational neurodegenerative disorders (CNDDs). Methods We identified 2563 reports on the incidence of eight conditions representing sporadic, acquired and genetic, protein-associated, i.e., conformational, NDD groups and age-related macular degeneration (AMD). We selected 245 papers for full-text examination and application of quality criteria. Additionally, data-collection was completed with detailed information from British, Swedish, and Spanish registries on Creutzfeldt-Jakob disease (CJD) forms, amyotrophic lateral sclerosis (ALS), and sporadic rapidly progressing neurodegenerative dementia (sRPNDd). For each condition, age-specific incidence curves, age-adjusted figures, and reported or calculated median survival were plotted and examined. Findings Based on 51 valid reported and seven new incidence data sets, nine out of eleven conditions shared specific features. Age-adjusted incidence per million person-years increased from ≤1.5 for sRPNDd, different CJD forms and Huntington's disease (HD), to 1589 and 2589 for AMD and Alzheimer's disease (AD) respectively. Age-specific profiles varied from (a) symmetrical, inverted V-shaped curves for low incidences to (b) those increasing with age for late-life sporadic CNDDs and for sRPNDd, with (c) a suggested, intermediate, non-symmetrical inverted V-shape for fronto-temporal dementia and Parkinson's disease. Frequently, peak age-specific incidences from 20–24 to ≥90 years increased with age at onset and survival. Distinct patterns were seen: for HD, with a low incidence, levelling off at middle age, and long median survival, 20 years; and for sRPNDd which displayed the lowest incidence, increasing with age, and a short median disease duration. Interpretation These results call for a unified population view of NDDs, with an age-at-onset-related pattern for acquired and sporadic CNDDs. The pattern linking age at onset to

  18. Topological conformal defects with tensor networks

    NASA Astrophysics Data System (ADS)

    Hauru, Markus; Evenbly, Glen; Ho, Wen Wei; Gaiotto, Davide; Vidal, Guifre

    2016-09-01

    The critical two-dimensional classical Ising model on the square lattice has two topological conformal defects: the Z2 symmetry defect Dɛ and the Kramers-Wannier duality defect Dσ. These two defects implement antiperiodic boundary conditions and a more exotic form of twisted boundary conditions, respectively. On the torus, the partition function ZD of the critical Ising model in the presence of a topological conformal defect D is expressed in terms of the scaling dimensions Δα and conformal spins sα of a distinct set of primary fields (and their descendants, or conformal towers) of the Ising conformal field theory. This characteristic conformal data {Δα,sα}D can be extracted from the eigenvalue spectrum of a transfer matrix MD for the partition function ZD. In this paper, we investigate the use of tensor network techniques to both represent and coarse grain the partition functions ZDɛand ZD σ of the critical Ising model with either a symmetry defect Dɛ or a duality defect Dσ. We also explain how to coarse grain the corresponding transfer matrices MDɛand MD σ, from which we can extract accurate numerical estimates of {Δα,sα}Dɛ and {Δα,sα}Dσ. Two key ingredients of our approach are (i) coarse graining of the defect D , which applies to any (i.e., not just topological) conformal defect and yields a set of associated scaling dimensions Δα, and (ii) construction and coarse graining of a generalized translation operator using a local unitary transformation that moves the defect, which only exist for topological conformal defects and yields the corresponding conformal spins sα.

  19. Conformal dynamical equivalence and applications

    NASA Astrophysics Data System (ADS)

    Spyrou, N. K.

    2011-02-01

    The "Conformal Dynamical Equivalence" (CDE) approach is briefly reviewed, and some of its applications, at various astrophysical levels (Sun, Solar System, Stars, Galaxies, Clusters of Galaxies, Universe as a whole), are presented. According to the CDE approach, in both the Newtonian and general-relativistic theories of gravity, the isentropic hydrodynamic flows in the interior of a bounded gravitating perfect-fluid source are dynamically equivalent to geodesic motions in a virtual, fully defined fluid source. Equivalently, the equations of hydrodynamic motion in the former source are functionally similar to those of the geodesic motions in the latter, physically, fully defined source. The CDE approach is followed for the dynamical description of the motions in the fluid source. After an observational introduction, taking into account all the internal physical characteristics of the corresponding perfect-fluid source, and based on the property of the isentropic hydrodynamic flows (quite reasonable for an isolated physical system), we examine a number of issues, namely, (i) the classical Newtonian explanation of the celebrated Pioneer-Anomaly effect in the Solar System, (ii) the possibility of both the attractive gravity and the repulsive gravity in a non-quantum Newtonian framework, (iii) the evaluation of the masses - theoretical, dynamical, and missing - and of the linear dimensions of non-magnetized and magnetized large-scale cosmological structures, (iv) the explanation of the flat-rotation curves of disc galaxies, (v) possible formation mechanisms of winds and jets, and (vi) a brief presentation of a conventional approach - toy model to the dynamics of the Universe, characterized by the dominant collisional dark matter (with its subdominant luminous baryonic "contamination"), correctly interpreting the cosmological observational data without the need of the notions dark energy, cosmological constant, and universal accelerating expansion.

  20. [ISO 9001 conformity in research, teaching and rehabilitation].

    PubMed

    Howorka, K; Kletschka, G; Pumprla, J; Thoma, H

    1998-01-01

    Quality assurance, in particular in the areas of development and production of medical devices, is one of the tasks of biomedical engineering. The interdisciplinary working group "Functional Rehabilitation and Group Education, Vienna" is committed to the development and implementation of group education models on three levels: (1) direct education/instruction of patients with chronic diseases, (2) university research and teaching, and (3) development of technical aids for rehabilitation and the means for disseminating group education models in rehabilitation and therapy. Major aims were, by generating conformity with ISO 9001 standards, to achieve greater transparency and process optimization with very small resources in university (teaching, research, technical aids) and extra-university (rehabilitation) areas. A secondary aim was the establishment of interdisciplinary (clinical and biomedical) cooperation at university level. In all main areas (research, teaching and group education/instruction), ISO 9001-conformity was achieved by our activities on three methodological levels: (1) description and analysis of processes, (2) use of ISO 9001 standards for evaluating internal processes, and (3) optimization measures. The following article contains relevant elements of the quality manual and quality assurance system, and offers a typical example of innovative cooperation between medicine and medical engineering.

  1. Conformity and Dissonance in Generalized Voter Models

    NASA Astrophysics Data System (ADS)

    Page, Scott E.; Sander, Leonard M.; Schneider-Mizell, Casey M.

    2007-09-01

    We generalize the voter model to include social forces that produce conformity among voters and avoidance of cognitive dissonance of opinions within a voter. The time for both conformity and consistency (which we call the exit time) is, in general, much longer than for either process alone. We show that our generalized model can be applied quite widely: it is a form of Wright's island model of population genetics, and is related to problems in the physical sciences. We give scaling arguments, numerical simulations, and analytic estimates for the exit time for a range of relative strengths in the tendency to conform and to avoid dissonance.

  2. Conformable Fractional Nikiforov—Uvarov Method

    NASA Astrophysics Data System (ADS)

    Karayer, H.; Demirhan, D.; Büyükkılıç, F.

    2016-07-01

    We introduce conformable fractional Nikiforov—Uvarov (NU) method by means of conformable fractional derivative which is the most natural definition in non-integer calculus. Since, NU method gives exact eigenstate solutions of Schrödinger equation (SE) for certain potentials in quantum mechanics, this method is carried into the domain of fractional calculus to obtain the solutions of fractional SE. In order to demonstrate the applicability of the conformable fractional NU method, we solve fractional SE for harmonic oscillator potential, Woods—Saxon potential, and Hulthen potential.

  3. Conformational and Vibrational Studies of Triclosan

    NASA Astrophysics Data System (ADS)

    Özişik, Haci; Bayari, S. Haman; Saǧlam, Semran

    2010-01-01

    The conformational equilibrium of triclosan (5-chloro-2-(2, 4-dichlorophenoxy) phenol) have been calculated using density functional theory (DFTe/B3LYP/6-311++G(d, p)) method. Four different geometries were found to correspond to energy minimum conformations. The IR spectrum of triclosan was measured in the 4000-400 cm-1 region. We calculated the harmonic frequencies and intensities of the most stable conformers in order to assist in the assignment of the vibrational bands in the experimental spectrum. The fundamental vibrational modes were characterized depending on their total energy distribution (TED%) using scaled quantum mechanical (SQM) force field method.

  4. Captopril and its dimer captopril disulfide: comparative structural and conformational studies.

    PubMed

    Bojarska, Joanna; Maniukiewicz, Waldemar; Fruziński, Andrzej; Sieroń, Lesław; Remko, Milan

    2015-03-01

    The crystal structures of captopril {systematic name: (2S)-1-[(2S)-2-methyl-3-sulfanylpropanoyl]pyrrolidine-2-carboxylic acid}, C(9)H(15)NO(3)S, (1), and its dimer disulfide metabolite, 1,1'-{disulfanediylbis[(2S)-2-methyl-1-oxopropane-3,1-diyl]}bis-L-proline, C(18)H(28)N(2)O(6)S(2), (2), were determined by single-crystal X-ray diffraction analysis. Compound (1) crystallizes in the orthorhombic space group P2(1)2(1)2(1), while compound (2) crystallizes in the monoclinic space group P2(1), both with one molecule per asymmetric unit. The molecular geometries of (1) and (2) are quite similar, but certain differences appear in the conformations of the five-membered proline rings and the side chains containing the sulfhydryl group. The proline ring adopts an envelope conformation in (1), while in (2) it exists in envelope and slightly deformed half-chair conformations. The conformation adopted by the side chain is extended in (1) and folded in (2). A minimum-energy conformational search using Monte Carlo methods in the aqueous phase reveals that the optimized conformations of the title compounds differ from those determined crystallographically, which depend on their immediate environment. Intermolecular O-H...O and relatively weak C-H...O interactions seem to be effective in both structures and, together with S-H...O and C-H...S contacts, they create three-dimensional networks.

  5. Rotational spectra of methyl ethyl and methyl propyl nitrosamines. Conformational assignment, internal rotation and quadrupole coupling

    NASA Astrophysics Data System (ADS)

    Walker, A. R. Hight; Lou, Qi; Bohn, Robert K.; Novick, Stewart E.

    1995-02-01

    A structural determination of two carcinogenic nitrosamines, methyl ethyl and methyl propyl nitrosamine, was performed. Microwave spectra were gathered from both a Stark cell spectrometer and a pulsed jet Fabry-Perot Fourier transform microwave spectrometer. Each rotational transition is split into quadrupole hyperfine components by two nitrogen nuclei. This quadrupole pattern is doubled by a low barrier methyl rotor which produces resolvable A and E states. Rotational spectra were assigned for one conformer of methyl ethyl nitrosamine and two conformers of methyl propyl nitrosamine. The lowest energy conformers of each compound, according to empirical force field calculations, were assigned. The structure found for methyl ethyl nitrosamine has the nitrosyl oxygen on the methyl side with the terminal methyl group of the ethyl chain in the gauche position (OMG). Both conformers of methyl propyl nitrosamine have the same skeletal structure as the methyl ethyl compound; one conformer has the terminal methyl of the propyl group in the anti position (OMGA) while the other conformer has this methyl in the gauche position (OMGG -). Rotational constants and quadrupole coupling constants are reported for each assigned species. A barrier to internal rotation of the N-methyl group in each compound is also reported.

  6. [Self-conciousness and conformity: moderating effects of conformity motives and task-interest].

    PubMed

    Oshimi, T

    2000-10-01

    This study investigated the relationship between self-consciousness and conforming behavior, with conformity motives and task-interest as their moderator variables. One hundred fifty-six (156) participants were asked to imagine themselves in a hypothetical conforming situation, and estimate the probability of their conforming behavior and various conformity motives behind it, as well as their interest in the task. They also completed Self-Consciousness Scale. Among low task-interest participants, those high on private self-consciousness conformed more than the low if either motive for avoidance of isolation or motive for fairness was high, while those high on public self-consciousness conformed more than the low if motive for avoidance of isolation was high. Among high task-interest participants, those high on private self-consciousness conformed less than the low, while those high on public self-consciousness conformed more than the low if motive for fairness was high. The relationship between conformity motives and standards of behavior was discussed.

  7. Nanoporous films: From conventional to the conformal

    DOE PAGES

    Allendorf, Mark D.; Stavila, Vitalie

    2015-12-14

    Here, thin and continuous films of porous metal-organic frameworks can now be conformally deposited on various substrates using a vapor-phase synthesis approach that departs from conventional solution-based routes.

  8. Theory of conformational transitions of viral shells

    NASA Astrophysics Data System (ADS)

    Guérin, Thomas; Bruinsma, Robijn

    2007-12-01

    We propose a continuum theory for the conformational transitions of viral shells. Conformational transitions of viral shells, as encountered during viral maturation, are associated with a soft mode instability of the capsid proteins [F. Tama and C. L. Brooks, J. Mol. Biol. 345(2), 299 (2005)]. The continuum theory presented here is an adaptation of the Ginzburg-Landau theory of soft-mode structural phase transitions of solids to viral shells. The theory predicts that the conformational transitions are characterized by a pronounced softening of the shell elasticity in the critical region. We demonstrate that the thermodynamics of the conformational transition can be probed quantitatively by a micromechanical atomic force microscope study. The external force can drive a capsid into a state of phase coexistence characterized by a highly nonlinear force deformation curve.

  9. Conformal Surface Parameterization for Texture Mapping

    DTIC Science & Technology

    1999-03-25

    Conformal Surface Parameterization for Texture Mapping Steven Haker Department of Electrical and Computer Engineering University of Minnesota...also like to thank Professor Victoria Interrante for some very helpful conversations on texture mappings. References [1] S. Angenent, S. Haker , A

  10. General Information for Transportation and Conformity

    EPA Pesticide Factsheets

    Transportation conformity is required by the Clean Air Act section 176(c) (42 U.S.C. 7506(c)) to ensure that federal funding and approval are given to highway and transit projects that are consistent with SIP.

  11. Conformational Electroresistance and Hysteresis in Nanoclusters

    DOE PAGES

    Li, Xiangguo; Zhang, Xiaoguang; Cheng, Hai-Ping

    2014-07-02

    Among many mechanisms proposed for electroresistance, ones involving structural changes are the least understood because of challenges of controllability and repeatability. Yet structural changes can cause dramatic changes in electronic properties, leading to multiple ways in which conduction paths can be opened and closed, not limited to filament movement or variation in molecular conductance. Here we show at least another way: conformational dependence of the Coulomb charging energy of a nanocluster, where charging induced conformational distortion changes the blockade voltage, which in turn leads to a giant electroresistance. This intricate interplay between charging and conformation change is demonstrated in amore » nanocluster Zn3O4 by combining a first-principles calculation with a temperature dependent transport model. The predicted hysteretic Coulomb blockade staircase in the current-voltage curve adds another dimension to the rich phenomenon of tunneling electroresistance. The new mechanism also provides a better controlled and repeatable platform to study conformational electroresistance.« less

  12. Galilean conformal mechanics from nonlinear realizations

    SciTech Connect

    Fedoruk, Sergey; Ivanov, Evgeny; Lukierski, Jerzy

    2011-04-15

    We apply the nonlinear realizations method for constructing new Galilean conformal mechanics models. Our starting point is the Galilean conformal algebra which is a nonrelativistic contraction of its relativistic counterpart. We calculate Maurer-Cartan one-forms, examine various choices of the relevant coset spaces, and consider the geometric inverse Higgs-type constraints which reduce the number of the independent coset parameters and, in some cases, provide dynamical equations. New Galilean conformally invariant actions are derived in arbitrary space-time dimension D=d+1 (no central charges), as well as in the special dimension D=2+1 with one exotic central charge. We obtain new classical mechanics models which extend the standard (D=0+1) conformal mechanics in the presence of d nonvanishing space dimensions.

  13. Conformational Electroresistance and Hysteresis in Nanoclusters

    SciTech Connect

    Li, Xiangguo; Zhang, Xiaoguang; Cheng, Hai-Ping

    2014-07-02

    Among many mechanisms proposed for electroresistance, ones involving structural changes are the least understood because of challenges of controllability and repeatability. Yet structural changes can cause dramatic changes in electronic properties, leading to multiple ways in which conduction paths can be opened and closed, not limited to filament movement or variation in molecular conductance. Here we show at least another way: conformational dependence of the Coulomb charging energy of a nanocluster, where charging induced conformational distortion changes the blockade voltage, which in turn leads to a giant electroresistance. This intricate interplay between charging and conformation change is demonstrated in a nanocluster Zn3O4 by combining a first-principles calculation with a temperature dependent transport model. The predicted hysteretic Coulomb blockade staircase in the current-voltage curve adds another dimension to the rich phenomenon of tunneling electroresistance. The new mechanism also provides a better controlled and repeatable platform to study conformational electroresistance.

  14. Social conformity despite individual preferences for distinctiveness.

    PubMed

    Smaldino, Paul E; Epstein, Joshua M

    2015-03-01

    We demonstrate that individual behaviours directed at the attainment of distinctiveness can in fact produce complete social conformity. We thus offer an unexpected generative mechanism for this central social phenomenon. Specifically, we establish that agents who have fixed needs to be distinct and adapt their positions to achieve distinctiveness goals, can nevertheless self-organize to a limiting state of absolute conformity. This seemingly paradoxical result is deduced formally from a small number of natural assumptions and is then explored at length computationally. Interesting departures from this conformity equilibrium are also possible, including divergence in positions. The effect of extremist minorities on these dynamics is discussed. A simple extension is then introduced, which allows the model to generate and maintain social diversity, including multimodal distinctiveness distributions. The paper contributes formal definitions, analytical deductions and counterintuitive findings to the literature on individual distinctiveness and social conformity.

  15. Conformally covariant parametrizations for relativistic initial data

    NASA Astrophysics Data System (ADS)

    Delay, Erwann

    2017-01-01

    We revisit the Lichnerowicz-York method, and an alternative method of York, in order to obtain some conformally covariant systems. This type of parametrization is certainly more natural for non constant mean curvature initial data.

  16. Mesh generation by conformal and quasiconformal mappings

    NASA Technical Reports Server (NTRS)

    Mastin, C. W.; Thompson, J. F.

    1981-01-01

    It is pointed out that many recent advances in the finite-difference solution of elliptic equations have been limited to regions whose boundary contours coincide with coordinate lines of the Cartesian coordinate system. The reason for this is related to the fact that in the case of an arbitrary curvilinear coordinate system the original equation becomes much more complex. However, there is no added complexity if an orthogonal coordinate system is generated from a conformal mapping. In the present investigation, a finite difference method developed for the construction of conformal mappings has been generalized to construct quasi-conformal mappings. It is expected that the use of more sophisticated numerical algorithms could lead to improvements in both speed and accuracy. Quasi-conformal mappings have applications not only in the solution of elliptic equations but also in other areas such as orthogonal mesh generation on surfaces and the solution of certain fluid flow problems.

  17. Solution conformation of peptides by the intramolecular nuclear Overhauser effect experiment. Study of valinomycin-K+.

    PubMed Central

    Krishna, N R; Agresti, D G; Glickson, J D; Walter, R

    1978-01-01

    This study demonstrates how the intramolecular nuclear Overhauser effect (NOE) experiment can be employed quantitatively to select from a set of possible conformations for a peptide or a protein the particular conformation (or a group of conformations) most consistent with the data. This procedure is demonstrated on a model depsipeptide system--valinomycin K+ in CDCl3--for which the solution conformation has been inferred by other methods. The NOE enhancements are very sensitive to the conformations assumed by this antibiotic. It is shown that the set of conformations, collectively labeled as A2 (including the X-ray crystallographic structure) gives a very good description of the NOE enhancements. The structure proposed by Bystrov et al. (1977. Eur. J. Biochem. 78:63) for the uncomplexed valinomycin in nonpolar solvents is also consistent with the experimental data on the potassium complex. Using statistical hypothesis testing involving the Hamilton R-factor ratio criterion, all the other models have been rejected as inconsistent with the experimental data. A general formalism is presented for describing the NOE effects in isotropically reorienting molecules. The formalism is not restricted to the extreme narrowing limit of the rotational correlation times and hence applies to both small and large molecules. Some of the factors that can influence the NOE measurements, viz. anisotropic rotational diffusion, conformational averaging, and nuclear spin diffusion, have been considered in this study. PMID:737287

  18. Conformal universe as false vacuum decay

    NASA Astrophysics Data System (ADS)

    Libanov, M.; Rubakov, V.

    2015-05-01

    We point out that the (pseudo)conformal universe scenario may be realized as the decay of a conformally invariant, metastable vacuum, which proceeds via spontaneous nucleation and subsequent growth of a bubble of a putative new phase. We study perturbations about the bubble and show that their leading late-time properties coincide with those inherent in the original models with homogeneously rolling backgrounds. In particular, the perturbations of a spectator dimension-zero field have a flat power spectrum.

  19. On useful conformal tranformations in general relativity

    NASA Astrophysics Data System (ADS)

    Carneiro, D. F.; Freiras, E. A.; Gonçalves, B.; de Lima, A. G.; Shapiro, I.

    2004-12-01

    Local conformal transformations are known as a useful tool in various applications of the gravitational theory, especially in cosmology. We describe some new aspects of these transformations, in particular using them for derivation of Einstein equations for the cosmological and Schwarzschild metrics. Furthermore, the conformal transformation is applied for the dimensional reduction of the Gauss-Bonnet topological invariant in $d=4$ to the spaces of lower dimensions.

  20. The conformal transformation of the night sky

    NASA Astrophysics Data System (ADS)

    Minguzzi, E.

    2016-12-01

    We give a simple differential geometric proof of the conformal transformation of the night sky under change of observer. The proof does not use the four dimensionality of spacetime or spinor methods. Furthermore, it really shows that the result does not depend on Lorentz transformations. This approach, by giving a transparent covariant expression to the conformal factor, shows that in most situations it is possible to define a thermal sky metric independent of the observer.

  1. A Lewis acid-mediated conformational switch.

    PubMed

    Knipe, Peter C; Lingard, Hannah; Jones, Ian M; Thompson, Sam; Hamilton, Andrew D

    2014-10-28

    Molecules that change conformation in response to a stimulus have numerous uses, such as artificial chemoreceptors, novel drug delivery strategies and liquid crystal technology. Here we describe the design, synthesis and conformational behaviour of an isonicotinamide-substituted diphenylacetylene upon recognition of Lewis acids, including metalloporphyrins. Binding of these at a remote site - the pyridyl nitrogen - increases hydrogen-bond donor ability of the proximal amide NH, causing an increased preference for the alkyne rotamer in which this hydrogen bond is maintained.

  2. Controlling complex networks with conformity behavior

    NASA Astrophysics Data System (ADS)

    Wang, Xu-Wen; Nie, Sen; Wang, Wen-Xu; Wang, Bing-Hong

    2015-09-01

    Controlling complex networks accompanied by common conformity behavior is a fundamental problem in social and physical science. Conformity behavior that individuals tend to follow the majority in their neighborhood is common in human society and animal communities. Despite recent progress in understanding controllability of complex networks, the existent controllability theories cannot be directly applied to networks associated with conformity. Here we propose a simple model to incorporate conformity-based decision making into the evolution of a network system, which allows us to employ the exact controllability theory to explore the controllability of such systems. We offer rigorous theoretical results of controllability for representative regular networks. We also explore real networks in different fields and some typical model networks, finding some interesting results that are different from the predictions of structural and exact controllability theory in the absence of conformity. We finally present an example of steering a real social network to some target states to further validate our controllability theory and tools. Our work offers a more realistic understanding of network controllability with conformity behavior and can have potential applications in networked evolutionary games, opinion dynamics and many other complex networked systems.

  3. Conformational properties of oxazoline-amino acids

    NASA Astrophysics Data System (ADS)

    Staś, Monika; Broda, Małgorzata A.; Siodłak, Dawid

    2016-04-01

    Oxazoline-amino acids (Xaa-Ozn) occur in natural peptides of potentially important bioactivity. The conformations of the model compounds: Ac-(S)-Ala-Ozn(4R-Me), Ac-(S)-Ala-Ozn(4S-Me), and (gauche+, gauche-, anti) Ac-(S)-Val-Ozn(4R-Me) were studied at meta-hybrid M06-2X/6-311++G(d,p) method including solvent effect. Boc-L-Ala-L-Ozn-4-COOMe and Boc-L-Val-L-Ozn-4-COOMe were synthesized and studied by FT-IR and NMR-NOE methods. The conformations in crystal state were gathered from the Cambridge Structural Data Base. The main conformational feature of the oxazoline amino acids is the conformation β2 (ϕ,ψ ∼ -161°, -6°), which predominates in weakly polar environment and still is accessible in polar surrounding. The changes of the conformational preferences towards the conformations αR (ϕ,ψ ∼ -70°, -15°) and then β (ϕ,ψ ∼ -57°, -155°) are observed with increase of the environment polarity.

  4. Coset spaces and Einstein manifolds with l-conformal Galilei symmetry

    NASA Astrophysics Data System (ADS)

    Chernyavsky, Dmitry

    2016-10-01

    The group theoretic construction is applied to construct a novel dynamical realization of the l-conformal Galilei group in terms of geodesic equations on the coset space. A peculiar feature of the geodesics is that all their integrals of motion, including the accelerations, are functionally independent. The analysis in the recent work [Chernyavsky and Galajinsky (2016) [35

  5. Holography beyond conformal invariance and AdS isometry?

    SciTech Connect

    Barvinsky, A. O.

    2015-03-15

    We suggest that the principle of holographic duality be extended beyond conformal invariance and AdS isometry. Such an extension is based on a special relation between functional determinants of the operators acting in the bulk and on its boundary, provided that the boundary operator represents the inverse propagators of the theory induced on the boundary by the Dirichlet boundary value problem in the bulk spacetime. This relation holds for operators of a general spin-tensor structure on generic manifolds with boundaries irrespective of their background geometry and conformal invariance, and it apparently underlies numerous O(N{sup 0}) tests of the AdS/CFT correspondence, based on direct calculation of the bulk and boundary partition functions, Casimir energies, and conformal anomalies. The generalized holographic duality is discussed within the concept of the “double-trace” deformation of the boundary theory, which is responsible in the case of large-N CFT coupled to the tower of higher-spin gauge fields for the renormalization group flow between infrared and ultraviolet fixed points. Potential extension of this method beyond the one-loop order is also briefly discussed.

  6. Impact of conformity on the evolution of cooperation in the prisoner’s dilemma game

    NASA Astrophysics Data System (ADS)

    Cui, Peng-Bi; Wu, Zhi-Xi

    2013-03-01

    We present an evolutionary model of the prisoner’s dilemma game taking into account two cognitive mechanisms: (1) payoff-biased strategy transmission and (2) a conformity mechanism involving a tendency to copy the most frequent nearby strategy in a group. Moreover, for two types of conformity, a minority mechanism and a majority rule, a dual process holds whereby the types differ in both the factors that give rise to them and the effects they have. By contrast, a signal process suggests that differences between the two forms of influence are primarily of degree and that fundamental processes are at work in both. We explore the model using both well-mixed and spatially structured populations. When the temptation to defect is low and both conformism and local interactions are present, the system can reach high levels of cooperation or even a full cooperation state. Furthermore, we find a stronger effect of conformity and a higher level of cooperation among the population regardless of the group size. This indicates that conformity follows a signal process. However, when the temptation to defect is rather large, results for the minority influence change non-monotonically with conformism cohesion. This is remarkably different from the results under majority rule, which is considered as support for the dual process.

  7. Conformal gauges and renormalized equations of motion in massless quantum electrodynamics

    NASA Astrophysics Data System (ADS)

    Petkova, V. B.; Sotkov, G. M.; Todorov, I. T.

    1985-03-01

    A formulation of massless QED is studied with a non-singular Lagrangian and conformal invariant equations of motion. It makes use of non-decomposable representations of the conformal group G and involves two dimensionless scalar fields (in addition to the conventional charged field and electromagnetic potential) but gauge invariant Green functions are shown to coincide with those of standard (massless) QED. Assuming that the (non-elementary) representation of G for the 5-potential which leaves the equations of motion invariant and leads to the free photon propagator of Johnson-Baker-Adler (JBA) conformal QED remains unaltered by renormalization, we prove that consistency requirements for conformal invariant 2-, 3-, and 4-point Green functions satisfying (renormalized) equations of motion and standard Ward identities lead to either a trivial solution (with eψ=0) or to a subcanonical dimension d=1/2 for the charged field.

  8. Conformational and functional analysis of molecular dynamics trajectories by Self-Organising Maps

    PubMed Central

    2011-01-01

    Background Molecular dynamics (MD) simulations are powerful tools to investigate the conformational dynamics of proteins that is often a critical element of their function. Identification of functionally relevant conformations is generally done clustering the large ensemble of structures that are generated. Recently, Self-Organising Maps (SOMs) were reported performing more accurately and providing more consistent results than traditional clustering algorithms in various data mining problems. We present a novel strategy to analyse and compare conformational ensembles of protein domains using a two-level approach that combines SOMs and hierarchical clustering. Results The conformational dynamics of the α-spectrin SH3 protein domain and six single mutants were analysed by MD simulations. The Cα's Cartesian coordinates of conformations sampled in the essential space were used as input data vectors for SOM training, then complete linkage clustering was performed on the SOM prototype vectors. A specific protocol to optimize a SOM for structural ensembles was proposed: the optimal SOM was selected by means of a Taguchi experimental design plan applied to different data sets, and the optimal sampling rate of the MD trajectory was selected. The proposed two-level approach was applied to single trajectories of the SH3 domain independently as well as to groups of them at the same time. The results demonstrated the potential of this approach in the analysis of large ensembles of molecular structures: the possibility of producing a topological mapping of the conformational space in a simple 2D visualisation, as well as of effectively highlighting differences in the conformational dynamics directly related to biological functions. Conclusions The use of a two-level approach combining SOMs and hierarchical clustering for conformational analysis of structural ensembles of proteins was proposed. It can easily be extended to other study cases and to conformational ensembles from

  9. The first experimental observation of the higher-energy trans conformer of trifluoroacetic acid

    NASA Astrophysics Data System (ADS)

    Apóstolo, R. F. G.; Bazsó, Gábor; Bento, R. R. F.; Tarczay, G.; Fausto, R.

    2016-12-01

    We report here the first experimental observation of the higher-energy conformer of trifluoroacetic acid (trans-TFA). The new conformer was generated by selective narrowband near-infrared vibrational excitation of the lower-energy cis-TFA conformer isolated in cryogenic matrices (Ar, Kr, N2) and shown to spontaneously decay to this latter form in the various matrix media, by tunneling. The decay rates in the different matrices were measured and compared with those of the trans conformers of other carboxylic acids in similar experimental conditions. The experimental studies received support from quantum chemistry calculations undertaken at various levels of approximation, which allowed a detailed characterization of the relevant regions of the potential energy surface of the molecule and the detailed assignment of the infrared spectra of the two conformers in the various matrices. Noteworthly, in contrast to cis-TFA that has its trifluoromethyl group eclipsed with the Cdbnd O bond of the carboxylic moiety, trans-TFA has the trifluoromethyl group eclipsed with the Csbnd O bond. This unusual structure of trans-TFA results from the fact that the relative orientation of the CF3 and COOH groups in this geometry facilitates the establishment of an intramolecular hydrogen-bond-like interaction between the OH group and the closely located in-plane fluorine atom of the CF3 moiety.

  10. Influence of packing interactions on the average conformation of B-DNA in crystalline structures.

    PubMed

    Tereshko, V; Subirana, J A

    1999-04-01

    The molecular interactions in crystals of oligonucleotides in the B form have been analysed and in particular the end-to-end interactions. Phosphate-phosphate interactions in dodecamers are also reviewed. A strong influence of packing constraints on the average conformation of the double helix is found. There is a strong relationship between the space group, the end-to-end interactions and the average conformation of DNA. Dodecamers must have a B-form average conformation with 10 +/- 0.1 base pairs per turn in order to crystallize in the P212121 and related space groups usually found. Decamers show a wider range of conformational variation, with 9.7-10. 6 base pairs per turn, depending on the terminal sequence and the space group. The influence of the space group in decamers is quite striking and remains unexplained. Only small variations are allowed in each case. Thus, crystal packing is strongly related to the average DNA conformation in the crystals and deviations from the average are rather limited. The constraints imposed by the crystal lattice explain why the average twist of the DNA in solution (10.6 base pairs per turn) is seldom found in oligonucleotides crystallized in the B form.

  11. Combat Air Forces Campaign Level Modernization Planning: A Study in Group Decision Making

    DTIC Science & Technology

    2003-03-01

    problems of influence from dominant individuals, irrelevant conversation, and pressure for conformity . Individuals can influence and dominate the...to counteract 52 the negative effects of dominant personalities, conversation not pursuant to the problem, and open group pressure for conformity ...discussion and debates. However, during the observed process, there was no blatant evidence of pressure for conformity or the exertion of influence

  12. [Conformation study of cyclic adenosine-3',5'-monophosphate and some of its derivatives by means of circular dichroism].

    PubMed

    Tunitskaia, V L; Guliaev, N N; Poletaev, A I; Severin, E S

    1977-04-01

    Circular dichroism spectra of adenosine and cyclic adenosine-3',5'-monophosphate (cAMP) and their derivatives, having different substituents in 8-position of heterocycle, are studied, cAMP is suggested to have preferable anti-conformation in the solution, while its derivatives with substituents in 8-position of purine base are preferable in sin-conformation. An exception is 8-(beta aminoethylamine-)cAMP, which has an anti-conformation within pH range from 4.5 to 9.5. This is probably due to the formation of intra-molecular ionic bond between cyclophosphate group and aliphatic amino group of 8-position substituent.

  13. Two-dimensional quantum gravity in the conformal gauge

    SciTech Connect

    Ahn, C.; Park, Y.; Kim, K.Y.; Kim, Y. ); Kim, W.; Cho, B. )

    1990-08-15

    Gravity coupled to a scalar field in two dimensions is analyzed in the conformal gauge. We obtain the solution of a scalar field. The residual symmetry associated with the scalar field is found from the invariance of the action and the covariance of the equation of motion of a scalar field. This symmetry is naturally related to the fact that the energy-momentum tensor satisfies the transformation rule of the usual second-rank tensor under SL(2,{ital R}){direct product}SL(2,{ital R}) group transformations for the coordinates {ital x}{sup +} and {ital x}{sup {minus}}.

  14. Conformational characterization of ceramides by nuclear magnetic resonance spectroscopy.

    PubMed Central

    Li, Li; Tang, Xiaoping; Taylor, K Grant; DuPré, Donald B; Yappert, M Cecilia

    2002-01-01

    Ceramide (Cer) has been identified as an active lipid second messenger in the regulation of cell growth, differentiation, and apoptosis. Its analog, dihydroceramide, without the 4 to 5 trans double bond in the sphingoid backbone lacks these biological effects. To establish the conformational features that distinguish ceramide from its analogs, nuclear magnetic resonance spectral data were acquired for diluted samples of ceramides (C2- and C18-Cer), dihydroceramide (C16-DHCer), and deoxydihydroceramide (C18-DODHCer). Our results suggest that in both C2- and C18-Cer, an H-bond network is formed in which the amide proton NH is donated to the OH groups on carbons C1 and C3 of the sphingosine backbone. Two tightly bound water molecules appear to stabilize this network by participating in flip-flop interactions with the hydroxyl groups. In DHCer, the lack of the trans double bond leads to a conformational distortion of this H-bonding motif. Without the critical double bond, the degree with which water molecules stabilize the H bonds between the two OH groups of the sphingolipid is reduced. This structural alteration might preclude the participation of DHCer in signaling-related interactions with cellular targets. PMID:11916863

  15. Memory conformity and the perceived accuracy of self versus other.

    PubMed

    Allan, Kevin; Midjord, J Palli; Martin, Doug; Gabbert, Fiona

    2012-02-01

    Here, we demonstrate that the decision to conform to another person's memory involves a strategic trade-off that balances the accuracy of one's own memory against that of another person. We showed participants three household scenes, one for 30 s, one for 60 s, and one for 120 s. Half were told that they would encode each scene for half as long as their virtual partner, and half were told that they would encode each scene for twice as long as their virtual partner. On a subsequent two-alternative-forced choice (2AFC) memory test, the simulated answer of the partner (accurate, errant, or no response) was shown before participants responded. Conformity to the partner's responses was significantly enhanced for the 30-s versus the 60- and 120-s scenes. This pattern, however, was present only in the group who believed that they had encoded each scene for half as long as their partner, even though the short-duration scene had the lowest baseline 2AFC accuracy in both groups and was also subjectively rated as the least memorable by both groups. Our reliance on other people's memory is therefore dynamically and strategically adjusted according to knowledge of the conditions under which we and other people have acquired different memories.

  16. 21 CFR 26.70 - Conformity assessment bodies.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Conformity assessment bodies. 26.70 Section 26.70...Frameworkâ Provisions § 26.70 Conformity assessment bodies. Each party recognizes that the conformity... conformity in relation to its requirements as specified in subpart B of this part. The parties shall...

  17. 40 CFR 91.106 - Certificate of conformity.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Certificate of conformity. 91.106... Provisions § 91.106 Certificate of conformity. (a) Every manufacturer of a new marine SI engine produced... obtain a certificate of conformity covering each engine family. The certificate of conformity must...

  18. 47 CFR 2.906 - Declaration of Conformity.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Declaration of Conformity. 2.906 Section 2.906... Conformity. (a) A Declaration of Conformity is a procedure where the responsible party, as defined in § 2.909... of Conformity attaches to all items subsequently marketed by the responsible party which...

  19. 40 CFR 91.106 - Certificate of conformity.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Certificate of conformity. 91.106... Provisions § 91.106 Certificate of conformity. (a) Every manufacturer of a new marine SI engine produced... obtain a certificate of conformity covering each engine family. The certificate of conformity must...

  20. 47 CFR 68.320 - Supplier's Declaration of Conformity.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 3 2011-10-01 2011-10-01 false Supplier's Declaration of Conformity. 68.320... Approval § 68.320 Supplier's Declaration of Conformity. (a) Supplier's Declaration of Conformity is a... Supplier's Declaration of Conformity attaches to all items subsequently marketed by the responsible...

  1. Arcjet Testing of Advanced Conformal Ablative TPS

    NASA Technical Reports Server (NTRS)

    Gasch, Matthew; Beck, Robin; Agrawal, Parul

    2014-01-01

    A conformable TPS over a rigid aeroshell has the potential to solve a number of challenges faced by traditional rigid TPS materials (such as tiled Phenolic Impregnated Carbon Ablator (PICA) system on MSL. The compliant (high strain to failure) nature of the conformable ablative materials will allow integration of the TPS with the underlying aeroshell structure much easier and enable monolithic-like configuration and larger segments (or parts) to be used. In May of 2013 the CA250 project executed an arcjet test series in the Ames IHF facility to evaluate a phenolic-based conformal system (named Conformal-PICA) over a range of test conditions from 40-400Wcm2. The test series consisted of four runs in the 13-inch diameter nozzle. Test models were based on SPRITE configuration (a 55-deg sphere cone), as it was able to provide a combination of required heat flux, pressure and shear within a single entry. The preliminary in-depth TC data acquired during that test series allowed a mid-fidelity thermal response model for conformal-PICA to be created while testing of seam models began to address TPS attachment and joining of multiple segments for future fabrication of large-scale aeroshells. Discussed in this paper are the results.

  2. Role of Conformation in - Interactions and Polymer/Fullerene Miscibility

    SciTech Connect

    Sumpter, Bobby G; Bucknall, David G.; Thio, Yonathan S; Gurun, Bilge; Campbell, Katie

    2011-01-01

    The origin of the miscibility between C60 fullerene and a series of phenylic vinyl polymers has been investigate using a combination of wide-angle x-ray (WAXS) and neutron (WANS) scattering and density functional theory (DFT) computational modeling. The solubility limit of the C60 in the polymers was found to increase non-linearly with increasing phenylic groups in the side-chain from 1 wt% in polystyrene (PS) to 12 wt% in poly(9-vinyl phenanthrene) (P9VPh). The DFT calculations showed that the polymer interacts with the fullerene preferentially with the phenylic groups in these vinyl polymers. However, due to the backbone these phenyl groups are unable to form the energetically favorable T-junction or planar - stacks with the fullerene, and are randomly oriented to the cage. The non-linear increase in solubility is believed to be associated with shape conformity of the three ring phenanthrene to the curvature of the fullerene.

  3. Is non-conformity WEIRD? Cultural variation in adults' beliefs about children's competency and conformity.

    PubMed

    Clegg, Jennifer M; Wen, Nicole J; Legare, Cristine H

    2017-03-01

    Cross-cultural comparisons provide critical insight into variation in reasoning about intelligence. In two studies, the authors used a novel methodology based on multivocal ethnography to assess the role of conformity in U.S. and Ni-Vanuatu adults' judgments of children's intelligence and, as a comparison trait, good behavior. In Study 1, there were cultural differences in the impact of conformity on U.S. and Ni-Vanuatu adults' judgments of children's intelligence and good behavior. When evaluating U.S. children only, U.S. adults were less likely to endorse high conformity children as intelligent, often citing creativity as a justification for their judgments. In contrast, Ni-Vanuatu adults were more likely to endorse Ni-Vanuatu high conformity children as intelligent. Ni-Vanuatu adults were also more likely to endorse high conformity children as well-behaved than U.S. adults. In Study 2, there were no effects of socioeconomic status on U.S. adults' evaluations of conformity. U.S. adults were less likely to endorse high conformity children as intelligent than Ni-Vanuatu adults. Taken together, the data demonstrate that beliefs about the relations between intelligence, conformity, and creativity vary within and across cultures. (PsycINFO Database Record

  4. Chimpanzees’ socially maintained food preferences indicate both conservatism and conformity

    PubMed Central

    Hopper, Lydia M.; Schapiro, Steven J.; Lambeth, Susan P.; Brosnan, Sarah F.

    2015-01-01

    Chimpanzees remain fixed on a single strategy, even if a novel, more efficient, strategy is introduced. Previous studies reporting such findings have incorporated paradigms in which chimpanzees learn one behavioural method and then are shown a new one that the chimpanzees invariably do not adopt. This study provides the first evidence that chimpanzees show such conservatism even when the new method employs the identical required behaviour as the first, but for a different reward. Groups of chimpanzees could choose to exchange one of two types of inedible tokens, with each token type being associated with a different food reward: one type was rewarded with a highly preferred food (grape) and the other type was rewarded with a less preferred food (carrot). Individuals first observed a model chimpanzee from their social group trained to choose one of the two types of tokens. In one group, this token earned a carrot, while in the other, control, group the token earned a grape. In both groups, chimpanzees conformed to the trained model’s choice. This was especially striking for those gaining the pieces of carrot, the less favoured reward. This resulted in a population-level trend of food choices, even when counter to their original, individual, preferences. Moreover, the chimpanzees’ food preferences did not change over time, demonstrating that these results were not due to a simple shift in preferences. We discuss social factors apparent in the interactions and suggest that, despite seeming to be inefficient, in chimpanzees, conformity may benefit them, possibly by assisting with the maintenance of group relations. PMID:27011390

  5. Cyclic Constraints on Conformational Flexibility in γ-PEPTIDES: Conformation-Specific IR and UV Spectroscopy

    NASA Astrophysics Data System (ADS)

    Walsh, Patrick S.; Kusaka, Ryoji; Zwier, Timothy S.; Fisher, Brian F.; Gellman, Samuel H.

    2013-06-01

    Spectroscopic studies of flexible peptides in the gas phase can provide insight to their inherent structural preferences in the absence of solvent. Recently, there has been increased attention paid to synthetic foldamers containing non-natural residues that can be specifically engineered to robustly form particular secondary structures. These engineered peptides have potential in therapeutic drug design because they are resistant to enzymatic degradation. Specifically, the Gellman group has synthesized a γ-peptide with a six membered cyclic constraint in the γ^{4}-γ^{3} position and an ethyl group at the γ^{2} position (γ_{ACHC}). The three stereocenters have a well-defined chirality [S,S,S]. These two features constrain the relative orientation of adjacent amide groups, thereby favoring a particular "pitch" to the turn. Solution phase results indicate that constrained γ-peptides induce the formation of a 14-helix. Ac-γ_{ACHC}-NHBz, its monohydrate and Ac-γ_{ACHC}-γ_{ACHC}-NHBz have been studied using ultraviolet (UV) and infrared (IR) double-resonance methods to obtain conformation-specific spectra under jet-cooled conditions in the gas phase. IR spectra in the hydride stretch (3300-3750 cm^{-1}), amide I/II and OH bend (1400-1800 cm^{-1}) were recorded and compared to predictions using density functional methods (DFT) and harmonic frequency calculations. We will compare the present results on constrained γ-peptides with corresponding results on unconstrained analogs. Data obtained for the monohydrated water cluster of Ac-γ_{ACHC}-NHBz will also be presented, including assignment of the water bend fundamental, which appears in the midst of transitions due to the amide II vibrations. L. Guo, W. Zhang, A. G. Reidenbach, M. W. Giuliano, I. A. Guzei, L. C. Spencer and S. H. Gellman Angew. Chem. Int. Ed. 2011, 50, 5843-5846

  6. Conformation and hydrogen ion titration of proteins: a continuum electrostatic model with conformational flexibility.

    PubMed

    You, T J; Bashford, D

    1995-11-01

    A new method for including local conformational flexibility in calculations of the hydrogen ion titration of proteins using macroscopic electrostatic models is presented. Intrinsic pKa values and electrostatic interactions between titrating sites are calculated from an ensemble of conformers in which the positions of titrating side chains are systematically varied. The method is applied to the Asp, Glu, and Tyr residues of hen lysozyme. The effects of different minimization and/or sampling protocols for both single-conformer and multi-conformer calculations are studied. For single-conformer calculations it is found that the results are sensitive to the choice of all-hydrogen versus polar-hydrogen-only atomic models and to the minimization protocol chosen. The best overall agreement of single-conformer calculations with experiment is obtained with an all-hydrogen model and either a two-step minimization process or minimization using a high dielectric constant. Multi-conformational calculations give significantly improved agreement with experiment, slightly smaller shifts between model compound pKa values and calculated intrinsic pKa values, and reduced sensitivity of the intrinsic pKa calculations to the initial details of the structure compared to single-conformer calculations. The extent of these improvements depends on the type of minimization used during the generation of conformers, with more extensive minimization giving greater improvements. The ordering of the titrations of the active-site residues, Glu-35 and Asp-52, is particularly sensitive to the minimization and sampling protocols used. The balance of strong site-site interactions in the active site suggests a need for including site-site conformational correlations.

  7. Conformal coatings : challenging environments lead to growth.

    SciTech Connect

    Challener, Cynthia A.

    2005-08-01

    Advances in technology have resulted in the need for electronic devices to continue functioning even when placed in harsh environments. Widespread use of cell phones, laptop computers, and other personal electronic devices, the increased number of electronic controls in home appliances, and the ever more extensive utilization of digital technology in the automotive industry have led to a growing demand for printed circuit boards (PCBs) that can perform under difficult conditions. Conformal coatings provide a protective barrier that enables the PCBs to function in these demanding environments. This growth in demand comes despite the cost and numerous difficulties associated with the application of these coatings. Many conformal coatings manufacturers are investing in the development of new technologies that minimize these difficulties. Others are involved in developing disruptive technologies that will serve as alternatives to traditional conformal coatings processes.

  8. Causality constraints in conformal field theory

    SciTech Connect

    Hartman, Thomas; Jain, Sachin; Kundu, Sandipan

    2016-05-17

    Causality places nontrivial constraints on QFT in Lorentzian signature, for example fixing the signs of certain terms in the low energy Lagrangian. In d dimensional conformal field theory, we show how such constraints are encoded in crossing symmetry of Euclidean correlators, and derive analogous constraints directly from the conformal bootstrap (analytically). The bootstrap setup is a Lorentzian four-point function corresponding to propagation through a shockwave. Crossing symmetry fixes the signs of certain log terms that appear in the conformal block expansion, which constrains the interactions of low-lying operators. As an application, we use the bootstrap to rederive the well known sign constraint on the (Φ)4 coupling in effective field theory, from a dual CFT. We also find constraints on theories with higher spin conserved currents. As a result, our analysis is restricted to scalar correlators, but we argue that similar methods should also impose nontrivial constraints on the interactions of spinning operators

  9. Causality constraints in conformal field theory

    NASA Astrophysics Data System (ADS)

    Hartman, Thomas; Jain, Sachin; Kundu, Sandipan

    2016-05-01

    Causality places nontrivial constraints on QFT in Lorentzian signature, for example fixing the signs of certain terms in the low energy Lagrangian. In d dimensional conformal field theory, we show how such constraints are encoded in crossing symmetry of Euclidean correlators, and derive analogous constraints directly from the conformal bootstrap (analytically). The bootstrap setup is a Lorentzian four-point function corresponding to propagation through a shockwave. Crossing symmetry fixes the signs of certain log terms that appear in the conformal block expansion, which constrains the interactions of low-lying operators. As an application, we use the bootstrap to rederive the well known sign constraint on the (∂ ϕ)4 coupling in effective field theory, from a dual CFT. We also find constraints on theories with higher spin conserved currents. Our analysis is restricted to scalar correlators, but we argue that similar methods should also impose nontrivial constraints on the interactions of spinning operators.

  10. Testing conformal gravity with astrophysical black holes

    NASA Astrophysics Data System (ADS)

    Bambi, Cosimo; Cao, Zheng; Modesto, Leonardo

    2017-03-01

    Weyl conformal symmetry can solve the problem the spacetime singularities present in Einstein's gravity. In a recent paper, two of us have found a singularity-free rotating black hole solution in conformal gravity. In addition to the mass M and the spin angular momentum J of the black hole, the new solution has a new parameter, L , which here we consider to be proportional to the black hole mass. Since the solution is conformally equivalent to the Kerr metric, photon trajectories are unchanged, while the structure of an accretion disk around a black hole is affected by the value of the parameter L . In this paper, we show that x-ray data of astrophysical black holes require L /M <1.2 .

  11. Understanding Modern Magnets through Conformal Mapping

    SciTech Connect

    Halbach, K.

    1989-10-27

    When I had to choose, within some narrow range, the topic of this paper, I received great help from a colleague in Berkeley and from Prof. Little when it was suggested that I should pick among the possible subjects of my talk the subject that Prof. Bloch would have enjoyed most. Since Prof. Bloch would prefer a scalpel over a sword every time, I hope and think that most people will approve my choice. When one intends to talk about a subject that is as old as conformal mapping and one does not want to lose the audience in a very short time, it is advisable to start by explaining both the motivation for the talk as well as the goals one has in mind when giving the talk. This particular talk has been motivated by the increasing frequency with which one hears, from people that ought to know better, statements like: 'Conformal mapping is really a thing of the past because of all the marvelous computer programs that we now have'. Even though, or more likely because, I have been intimately involved in the development of some large and widely used computer codes, I am deeply disturbed by such statements since they indicate a severe lack of understanding of the purpose of conformal mapping techniques, computers, and computer codes. In my view, conformal mapping can be an extremely powerful computational technique, and the easy availability of computers has made that aspect even more important now than it has been in the past. Additionally, and more importantly, conformal mapping can give very deep and unique insight into problems, giving often solutions to problems that can not be obtained with any other method, in particular not with computers. Wanting to demonstrate in particular the latter part, I set myself two goals for this talk: (1) I want to show with the help of a number of examples that conformal mapping is a unique and enormously powerful tool for thinking about, and solving, problems. Usually one has to write down only a few equations, and sometimes none at all

  12. Spectral Analysis of a Protein Conformational Switch

    NASA Astrophysics Data System (ADS)

    Rackovsky, S.

    2011-06-01

    The existence of conformational switching in proteins, induced by single amino acid mutations, presents an important challenge to our understanding of the physics of protein folding. Sequence-local methods, commonly used to detect structural homology, are incapable of accounting for this phenomenon. We examine a set of proteins, derived from the GA and GB domains of Streptococcus protein G, which are known to show a dramatic conformational change as a result of single-residue replacement. It is shown that these sequences, which are almost identical locally, can have very different global patterns of physical properties. These differences are consistent with the observed complete change in conformation. These results suggest that sequence-local methods for identifying structural homology can be misleading. They point to the importance of global sequence analysis in understanding sequence-structure relationships.

  13. Cosmological particle creation in conformal gravity

    NASA Astrophysics Data System (ADS)

    Berezin, Victor; Dokuchaev, Vyacheslav; Eroshenko, Yury

    2016-10-01

    We constructed the conformally invariant model for scalar particle creation induced by strong gravitational fields. Starting from the "usual" hydrodynamical description of the particle motion written in the Eulerian coordinates we substituted the particle number conservation law (which enters the formalism) by "the particle creation law", proportional to the square of the Weyl tensor (following the famous result by Ya. B. Zel`dovich and A. A. Starobinsky). Then, demanding the conformal invariance of the whole dynamical system, we have got both the (Weyl)-conformal gravity and the Einstein-Hilbert-dilaton gravity action integral. Thus, we obtained something like the induced gravity suggested first by A. D. Sakharov. It is shown that the resulting system is self-consistent. Some future developments of the theory are discussed in the concluding Chapter.

  14. Logarithm conformal mapping brings the cloaking effect

    PubMed Central

    Xu, Lin; Chen, Huanyang

    2014-01-01

    Over the past years, invisibility cloaks have been extensively discussed since transformation optics emerges. Generally, the electromagnetic parameters of invisibility cloaks are complicated tensors, yet difficult to realize. As a special method of transformation optics, conformal mapping helps us design invisibility cloak with isotropic materials of a refractive index distribution. However, for all proposed isotropic cloaks, the refractive index range is at such a breadth that challenges current experimental fabrication. In this work, we propose two new kinds of logarithm conformal mappings for invisible device designs. For one of the mappings, the refractive index distribution of conformal cloak varies from 0 to 9.839, which is more feasible for future implementation. Numerical simulations by using finite element method are performed to confirm the theoretical analysis. PMID:25359138

  15. Social conformity persists at least one day in 6-year-old children.

    PubMed

    Sun, Sai; Yu, Rongjun

    2016-12-21

    Humans have a tendency to forgo their own attitudes or beliefs in order to better align with the interests of a majority, a behavioral process known as conformity. Social conformity has been widely studied among adults and adolescents, whereas experimental studies on the impact of peer influence among young children have been relatively limited. The current study aims to investigate both short-term and sustained conforming behaviors among children in situations of relatively low social pressure. Forty-one children aged 5 to 6 years rated the attractiveness of 90 faces presented serially followed by witnessing a group rating in the absence of peers. Subsequently, second judgement was made after 30 minutes (Experiment 1). Results show that 6-year-old children tended to conform to their peers when group ratings differed from their own ratings, while younger children did not. In Experiment 2, children were required to make the second judgment one day after exposure to group ratings. Similarly, children aged 6 years exhibited a sustained conformity effect even after one day. Our findings suggest that 6-year-old children spontaneously change their private opinions under implicit social influence from peers.

  16. Social conformity persists at least one day in 6-year-old children

    PubMed Central

    Sun, Sai; Yu, Rongjun

    2016-01-01

    Humans have a tendency to forgo their own attitudes or beliefs in order to better align with the interests of a majority, a behavioral process known as conformity. Social conformity has been widely studied among adults and adolescents, whereas experimental studies on the impact of peer influence among young children have been relatively limited. The current study aims to investigate both short-term and sustained conforming behaviors among children in situations of relatively low social pressure. Forty-one children aged 5 to 6 years rated the attractiveness of 90 faces presented serially followed by witnessing a group rating in the absence of peers. Subsequently, second judgement was made after 30 minutes (Experiment 1). Results show that 6-year-old children tended to conform to their peers when group ratings differed from their own ratings, while younger children did not. In Experiment 2, children were required to make the second judgment one day after exposure to group ratings. Similarly, children aged 6 years exhibited a sustained conformity effect even after one day. Our findings suggest that 6-year-old children spontaneously change their private opinions under implicit social influence from peers. PMID:28000745

  17. Energetically unfavorable amide conformations for N6-acetyllysine side chains in refined protein structures.

    PubMed

    Genshaft, Alexander; Moser, Joe-Ann S; D'Antonio, Edward L; Bowman, Christine M; Christianson, David W

    2013-06-01

    The reversible acetylation of lysine to form N6-acetyllysine in the regulation of protein function is a hallmark of epigenetics. Acetylation of the positively charged amino group of the lysine side chain generates a neutral N-alkylacetamide moiety that serves as a molecular "switch" for the modulation of protein function and protein-protein interactions. We now report the analysis of 381 N6-acetyllysine side chain amide conformations as found in 79 protein crystal structures and 11 protein NMR structures deposited in the Protein Data Bank (PDB) of the Research Collaboratory for Structural Bioinformatics. We find that only 74.3% of N6-acetyllysine residues in protein crystal structures and 46.5% in protein NMR structures contain amide groups with energetically preferred trans or generously trans conformations. Surprisingly, 17.6% of N6-acetyllysine residues in protein crystal structures and 5.3% in protein NMR structures contain amide groups with energetically unfavorable cis or generously cis conformations. Even more surprisingly, 8.1% of N6-acetyllysine residues in protein crystal structures and 48.2% in NMR structures contain amide groups with energetically prohibitive twisted conformations that approach the transition state structure for cis-trans isomerization. In contrast, 109 unique N-alkylacetamide groups contained in 84 highly accurate small molecule crystal structures retrieved from the Cambridge Structural Database exclusively adopt energetically preferred trans conformations. Therefore, we conclude that cis and twisted N6-acetyllysine amides in protein structures deposited in the PDB are erroneously modeled due to their energetically unfavorable or prohibitive conformations.

  18. Conformal coordinates associated with uniformly accelerated motion

    NASA Technical Reports Server (NTRS)

    Jones, R. T.

    1976-01-01

    Specific problems in the theory of relativity are often simplified by an appropriate choice of the coordinate system. Restricted conformal coordinates provide an especially simple analysis of motion with uniform acceleration, known as hyperbolic motion. Conformal coordinates x', t' may be obtained from Cartesian coordinates x, t by the transformation x'+ct'=F(x+ct) and x'-ct'=G(x-ct), where c is the velocity of light. A variable motion of the x' system is determined by the choice of the functions F and G.

  19. Simulating Massive Conformation Changes within Polypeptide Systems

    NASA Astrophysics Data System (ADS)

    Singh, Jaspinder Paul

    In this dissertation I employ all-atom structure based models with stable energy basins to several existing and novel polypeptide systems (postulated conformation changes of the mammalian prion protein and structurally dual proteins). The common themes are finding unfolding and refolding pathways between highly dissimilar protein structures as a means of understanding exactly how and why a protein may misfold. The modeling is based on the energy funnel landscape theory of protein conformation space. The principle of minimal frustration is considered as the model includes parameters which vary the roughness of the landscape and give rise to off-pathway misfoldings. The dual basin model is applied to the C-terminal (residues 166-226) of the mammalian prion protein. One basin represents the known alpha-helical (aH) structure while the other represents the same residues in a lefthanded beta-helical (LHBH) conformation. The LHBH structure has been proposed to help describe one class of in vitro grown fibrils, as well as possibly self-templating the conversion of normal cellular prion protein to the infectious form. Yet, it is unclear how the protein may make this global rearrangement. Our results demonstrate that the conformation changes are not strongly limited by large-scale geometry modification and that there may exist an overall preference for the LHBH conformation. Furthermore, our model presents novel intermediate trapping conformations with twisted LHBH structure. Polypeptides that display structural duality have primary structures that can give rise to different potential native conformations. We apply the structure-based all-atom model to a leucine zipper protein template with a stable aH structure that has been shown in experiment to switch to a β hairpin structure when exposed to a low-pH environment. We show that the model can be used to perform large-scale temperature-dependent conformational switching by simulating this switching behavior. We augmented

  20. Recent progress in irrational conformal field theory

    SciTech Connect

    Halpern, M.B.

    1993-09-01

    In this talk, I will review the foundations of irrational conformal field theory (ICFT), which includes rational conformal field theory as a small subspace. Highlights of the review include the Virasoro master equation, the Ward identities for the correlators of ICFT and solutions of the Ward identities. In particular, I will discuss the solutions for the correlators of the g/h coset construction and the correlators of the affine-Sugawara nests on g {contains} h{sub 1} {contains} {hor_ellipsis} {contains} h{sub n}. Finally, I will discuss the recent global solution for the correlators of all the ICFT`s in the master equation.

  1. Isoperimetric inequality on conformally hyperbolic manifolds

    SciTech Connect

    Kesel'man, V M

    2003-04-30

    It is shown that on an arbitrary non-compact Riemannian manifold of conformally hyperbolic type the isoperimetric inequality can be taken by a conformal change of the metric to the same canonical linear form as in the case of the standard hyperbolic Lobachevskii space. Both the absolute isoperimetric inequality and the relative one (for manifolds with boundary) are obtained. This work develops the results and methods of a joint paper with Zorich, in which the absolute isoperimetric inequality was obtained under a certain additional condition; the resulting statements are definitive in a certain sense.

  2. Consistency relations for the conformal mechanism

    SciTech Connect

    Creminelli, Paolo; Joyce, Austin; Khoury, Justin; Simonović, Marko E-mail: joyceau@sas.upenn.edu E-mail: marko.simonovic@sissa.it

    2013-04-01

    We systematically derive the consistency relations associated to the non-linearly realized symmetries of theories with spontaneously broken conformal symmetry but with a linearly-realized de Sitter subalgebra. These identities relate (N+1)-point correlation functions with a soft external Goldstone to N-point functions. These relations have direct implications for the recently proposed conformal mechanism for generating density perturbations in the early universe. We study the observational consequences, in particular a novel one-loop contribution to the four-point function, relevant for the stochastic scale-dependent bias and CMB μ-distortion.

  3. Isoperimetric inequality on conformally hyperbolic manifolds

    NASA Astrophysics Data System (ADS)

    Kesel'man, V. M.

    2003-04-01

    It is shown that on an arbitrary non-compact Riemannian manifold of conformally hyperbolic type the isoperimetric inequality can be taken by a conformal change of the metric to the same canonical linear form as in the case of the standard hyperbolic Lobachevskii space. Both the absolute isoperimetric inequality and the relative one (for manifolds with boundary) are obtained.This work develops the results and methods of a joint paper with Zorich, in which the absolute isoperimetric inequality was obtained under a certain additional condition; the resulting statements are definitive in a certain sense.

  4. Conformal pure radiation with parallel rays

    NASA Astrophysics Data System (ADS)

    Leistner, Thomas; Nurowski, Paweł

    2012-03-01

    We define pure radiation metrics with parallel rays to be n-dimensional pseudo-Riemannian metrics that admit a parallel null line bundle K and whose Ricci tensor vanishes on vectors that are orthogonal to K. We give necessary conditions in terms of the Weyl, Cotton and Bach tensors for a pseudo-Riemannian metric to be conformal to a pure radiation metric with parallel rays. Then, we derive conditions in terms of the tractor calculus that are equivalent to the existence of a pure radiation metric with parallel rays in a conformal class. We also give analogous results for n-dimensional pseudo-Riemannian pp-waves.

  5. On conformal higher spin wave operators

    NASA Astrophysics Data System (ADS)

    Nutma, Teake; Taronna, Massimo

    2014-06-01

    We analyze free conformal higher spin actions and the corresponding wave operators in arbitrary even dimensions and backgrounds. We show that the wave operators do not factorize in general, and identify the Weyl tensor and its derivatives as the obstruction to factorization. We give a manifestly factorized form for them on (A)dS backgrounds for arbitrary spin and on Einstein backgrounds for spin 2. We are also able to fix the conformal wave operator in d = 4 for s = 3 up to linear order in the Riemann tensor on generic Bach-flat backgrounds.

  6. Cauchy Conformal Fields in Dimensions {d > 2}

    NASA Astrophysics Data System (ADS)

    Friedan, Daniel; Keller, Christoph A.

    2016-12-01

    Holomorphic fields play an important role in 2d conformal field theory. We generalize them to {d > 2} by introducing the notion of Cauchy conformal fields, which satisfy a first order differential equation such that they are determined everywhere once we know their value on a codimension 1 surface. We classify all the unitary Cauchy fields. By analyzing the mode expansion on the unit sphere, we show that all unitary Cauchy fields are free in the sense that their correlation functions factorize on the 2-point function. We also discuss the possibility of non-unitary Cauchy fields and classify them in d = 3 and 4.

  7. Conformational equilibria and large-amplitude motions in dimers of carboxylic acids: rotational spectrum of acetic acid-difluoroacetic acid.

    PubMed

    Gou, Qian; Feng, Gang; Evangelisti, Luca; Caminati, Walther

    2014-10-06

    We report the rotational spectra of two conformers of the acetic acid-difluoroacetic acid adduct (CH3COOH-CHF2COOH) and supply information on its internal dynamics. The two conformers differ from each other, depending on the trans or gauche orientation of the terminal -CHF2 group. Both conformers display splittings of the rotational transitions, due to the internal rotation of the methyl group of acetic acid. The corresponding barriers are determined to be V3(trans)=99.8(3) and V3(gauche)=90.5(9) cm(-1) (where V3 is the methyl rotation barrier height). The gauche form displays a further doubling of the rotational transitions, due to the tunneling motion of the -CHF2 group between its two equivalent conformations. The corresponding B2 barrier is estimated to be 108(2) cm(-1). The increase in the distance between the two monomers upon OH→OD deuteration (the Ubbelohde effect) is determined.

  8. The dynamics, structure, and conformational free energy of proline-containing antifreeze glycoprotein.

    PubMed Central

    Nguyen, Dat H; Colvin, Michael E; Yeh, Yin; Feeney, Robert E; Fink, William H

    2002-01-01

    Recent NMR studies of the solution structure of the 14-amino acid antifreeze glycoprotein AFGP-8 have concluded that the molecule lacks long-range order. The implication that an apparently unstructured molecule can still have a very precise function as a freezing inhibitor seems startling at first consideration. To gain insight into the nature of conformations and motions in AFGP-8, we have undertaken molecular dynamics simulations augmented with free energy calculations using a continuum solvation model. Starting from 10 different NMR structures, 20 ns of dynamics of AFGP were explored. The dynamics show that AFGP structure is composed of four segments, joined by very flexible pivots positioned at alanine 5, 8, and 11. The dynamics also show that the presence of prolines in this small AFGP structure facilitates the adoption of the poly-proline II structure as its overall conformation, although AFGP does adopt other conformations during the course of dynamics as well. The free energies calculated using a continuum solvation model show that the lowest free energy conformations, while being energetically equal, are drastically different in conformations. In other words, this AFGP molecule has many structurally distinct and energetically equal minima in its energy landscape. In addition, conformational, energetic, and hydrogen bond analyses suggest that the intramolecular hydrogen bonds between the N-acetyl group and the protein backbone are an important integral part of the overall stability of the AFGP molecule. The relevance of these findings to the mechanism of freezing inhibition is discussed. PMID:12023212

  9. Nucleotide Dependent Switching in Rho GTPase: Conformational Heterogeneity and Competing Molecular Interactions

    PubMed Central

    Kumawat, Amit; Chakrabarty, Suman; Kulkarni, Kiran

    2017-01-01

    Ras superfamily of GTPases regulate myriad cellular processes through a conserved nucleotide (GTP/GDP) dependent switching mechanism. Unlike Ras family of GTPases, for the Rho GTPases, there is no clear evidence for the existence of “sub-states” such as state 1 & state 2 in the GTP bound form. To explore the nucleotide dependent conformational space of the Switch I loop and also to look for existence of state 1 like conformations in Rho GTPases, atomistic molecular dynamics and metadynamics simulations on RhoA were performed. These studies demonstrate that both the nucleotide-free state and the GDP bound “OFF” state have very similar conformations, whereas the GTP bound “ON” state has unique conformations with signatures of two intermediate states. The conformational free energy landscape for these systems suggests the presence of multiple intermediate states. Interestingly, the energetic penalty of exposing the non-polar residues in the GTP bound form is counter balanced by the favourable hydrogen bonded interactions between the γ-phosphate group of GTP with the highly conserved Tyr34 and Thr37 residues. These competing molecular interactions lead to a tuneable energy landscape of the Switch I conformation, which can undergo significant changes based on the local environment including changes upon binding to effectors. PMID:28374773

  10. In God we trust? Neural measures reveal lower social conformity among non-religious individuals.

    PubMed

    Thiruchselvam, Ravi; Gopi, Yashoda; Kilekwang, Leonard; Harper, Jessica; Gross, James J

    2017-02-21

    Even in predominantly religious societies, there are substantial individual differences in religious commitment. Why is this? One possibility is that differences in social conformity (i.e., the tendency to think and behave as others do) underlie inclination towards religiosity. However, the link between religiosity and conformity has not yet been directly examined. In this study, we tested the notion that non-religious individuals show dampened social conformity, using both self-reported and neural (EEG-based ERPs) measures of sensitivity to others' influence. Non-religious versus religious undergraduate subjects completed an experimental task that assessed levels of conformity in a domain unrelated to religion (i.e., in judgments of facial attractiveness). Findings showed that, although both groups yielded to conformity pressures at the self-report level, non-religious individuals did not yield to such pressures in their neural responses. These findings highlight a novel link between religiosity and social conformity, and hold implications for prominent theories about the psychological functions of religion.

  11. Modified Amber Force Field Correctly Models the Conformational Preference for Tandem GA pairs in RNA

    PubMed Central

    2015-01-01

    Molecular mechanics with all-atom models was used to understand the conformational preference of tandem guanine-adenine (GA) noncanonical pairs in RNA. These tandem GA pairs play important roles in determining stability, flexibility, and structural dynamics of RNA tertiary structures. Previous solution structures showed that these tandem GA pairs adopt either imino (cis Watson–Crick/Watson–Crick A-G) or sheared (trans Hoogsteen/sugar edge A-G) conformations depending on the sequence and orientation of the adjacent closing base pairs. The solution structures (GCGGACGC)2 [Biochemistry, 1996, 35, 9677–9689] and (GCGGAUGC)2 [Biochemistry, 2007, 46, 1511–1522] demonstrate imino and sheared conformations for the two central GA pairs, respectively. These systems were studied using molecular dynamics and free energy change calculations for conformational changes, using umbrella sampling. For the structures to maintain their native conformations during molecular dynamics simulations, a modification to the standard Amber ff10 force field was required, which allowed the amino group of guanine to leave the plane of the base [J. Chem. Theory Comput., 2009, 5, 2088–2100] and form out-of-plane hydrogen bonds with a cross-strand cytosine or uracil. The requirement for this modification suggests the importance of out-of-plane hydrogen bonds in stabilizing the native structures. Free energy change calculations for each sequence demonstrated the correct conformational preference when the force field modification was used, but the extent of the preference is underestimated. PMID:24803859

  12. Crystal structure of the hydrated strontium salt of methotrexate: two independent molecules with different conformations.

    PubMed

    Mastropaolo, D; Camerman, A; Camerman, N

    2001-01-18

    The crystal and molecular structure of methotrexate has been determined by X-ray diffraction from a highly hydrated triclinic crystal form in which the asymmetric unit contains two independent methotrexate molecules with their glutamate carboxyl groups coordinated to two strontium ions. The two methotrexates exhibit differing conformations: They are almost related to one another by a pseudocenter of symmetry. This places the C(9)-N(10) bond vectors on opposite sides of the planes of the pteridine rings. The 2,4-diaminopteridines form 2-fold symmetry-related hydrogen-bonded dimers as well as hydrogen bonds to benzoyl carbonyl oxygens and lattice water molecules. This structure provides experimental proof of the existence of pteridine conformers through rotation about the C(6)-C(9) bond. Comparison of these conformers with other free and enzyme-bound methotrexate conformations shows them all to be different and illustrates the ability of the molecule to adapt to its chemical environment. The results from this crystal structure determination are experimental proof that methotrexate has not one preferred molecular conformation but may freely rotate about several bonds. They also suggest that the dihydrofolate reductase-bound methotrexate conformation is greatly influenced by the specific binding site environment of the enzyme.

  13. Group X

    SciTech Connect

    Fields, Susannah

    2007-08-16

    This project is currently under contract for research through the Department of Homeland Security until 2011. The group I was responsible for studying has to remain confidential so as not to affect the current project. All dates, reference links and authors, and other distinguishing characteristics of the original group have been removed from this report. All references to the name of this group or the individual splinter groups has been changed to 'Group X'. I have been collecting texts from a variety of sources intended for the use of recruiting and radicalizing members for Group X splinter groups for the purpose of researching the motivation and intent of leaders of those groups and their influence over the likelihood of group radicalization. This work included visiting many Group X websites to find information on splinter group leaders and finding their statements to new and old members. This proved difficult because the splinter groups of Group X are united in beliefs, but differ in public opinion. They are eager to tear each other down, prove their superiority, and yet remain anonymous. After a few weeks of intense searching, a list of eight recruiting texts and eight radicalizing texts from a variety of Group X leaders were compiled.

  14. Group Flow and Group Genius

    ERIC Educational Resources Information Center

    Sawyer, Keith

    2015-01-01

    Keith Sawyer views the spontaneous collaboration of group creativity and improvisation actions as "group flow," which organizations can use to function at optimum levels. Sawyer establishes ideal conditions for group flow: group goals, close listening, complete concentration, being in control, blending egos, equal participation, knowing…

  15. Synthesis, conformational parameters and packing considerations of methyl bispyridyl ketones

    NASA Astrophysics Data System (ADS)

    Weck, Christian; Katzsch, Felix; Gruber, Tobias

    2015-10-01

    The crystal structures of two bispyridyl ketones featuring either two methyl residues or one methyl and one bromomethyl residue, respectively, are presented. In order to elucidate the influence of the substituents, a comprehensive comparison with the non-methylated mother compound has been performed. A special focus lies thereby on the relative position of the heteroatoms and their free electron pairs. The two methyl groups at the bispyridyl ketone result in two molecules in the asymmetric unit adopting rather different conformations. Due to the fast crystallization conditions and a melting point differing from the literature, a polymorph close to a local minimum in the energy hypersurface seems possible. After introducing a bromine atom to one of the two methyl groups, the molecular conformation is very similar to the unsubstituted molecule. The packing of both title compounds is dominated by weak contacts of the C-H⋯π and C-H⋯Y type (Y = O, N) and C-H⋯Br- and Br⋯π-contacts for the brominated molecule.

  16. Complex ion effects on polypeptide conformational stability: chloride and sulfate salts of guanidinium and tetrapropylammonium.

    PubMed

    Dempsey, Christopher E; Mason, Philip E; Jungwirth, Pavel

    2011-05-18

    The effects of chloride and sulfate salts of tetrapropylammonium (TPA(+)) and guanidinium (Gdm(+)) on the conformational stabilities of tryptophan zipper (trpzip) and α-helical (alahel) peptides were measured by circular dichroism spectroscopy. Like Gdm(+), TPA(+) interacts with the planar tryptophan indole group, perturbing the conformational stability of trpzip peptides. TPA(+) effects are largely unaffected by sulfate, indicating an absence of the heteroion pairing that is observed in concentrated Gdm(2)SO(4) solutions. TPA(+) stabilizes helical conformations in alahel peptides, indicating exclusion from the peptide bond. The observations are broadly consistent with predictions of molecular dynamics simulations [Mason, P. E.; et al. J. Phys. Chem. B2009, 113, 3227-3234], indicating that the effects of complex ions on proteins are increasingly predictable in terms of ion hydration, complementary interactions with specific protein groups, and ion-pairing contributions.

  17. Rotational spectroscopy of antipyretics: Conformation, structure, and internal dynamics of phenazone

    NASA Astrophysics Data System (ADS)

    Écija, Patricia; Cocinero, Emilio J.; Lesarri, Alberto; Fernández, José A.; Caminati, Walther; Castaño, Fernando

    2013-03-01

    The conformational and structural preferences of phenazone (antipyrine), the prototype of non-opioid pyrazolone antipyretics, have been probed in a supersonic jet expansion using rotational spectroscopy. The conformational landscape of the two-ring assembly was first explored computationally, but only a single conformer was predicted, with the N-phenyl and N-methyl groups on opposite sides of the pyrazolone ring. Consistently, the microwave spectrum evidenced a rotational signature arising from a single molecular structure. The spectrum exhibited very complicated fine and hyperfine patterns (not resolvable with any other spectroscopic technique) originated by the simultaneous coupling of the methyl group internal rotation and the spins of the two 14N nuclei with the overall rotation. The internal rotation tunnelling was ascribed to the C-CH3 group and the barrier height established experimentally (7.13(10) kJ mol-1). The internal rotation of the N-CH3 group has a lower limit of 9.4 kJ mol-1. The structure of the molecule was determined from the rotational parameters, with the phenyl group elevated ca. 25° with respect to the average plane of the pyrazolic moiety and a phenyl torsion of ca. 52°. The origin of the conformational preferences is discussed in terms of the competition between intramolecular C-H⋯N and C-H⋯O weak hydrogen bonds.

  18. NMR Studies of Dynamic Biomolecular Conformational Ensembles

    PubMed Central

    Torchia, Dennis A.

    2015-01-01

    Multidimensional heteronuclear NMR approaches can provide nearly complete sequential signal assignments of isotopically enriched biomolecules. The availability of assignments together with measurements of spin relaxation rates, residual spin interactions, J-couplings and chemical shifts provides information at atomic resolution about internal dynamics on timescales ranging from ps to ms, both in solution and in the solid state. However, due to the complexity of biomolecules, it is not possible to extract a unique atomic-resolution description of biomolecular motions even from extensive NMR data when many conformations are sampled on multiple timescales. For this reason, powerful computational approaches are increasingly applied to large NMR data sets to elucidate conformational ensembles sampled by biomolecules. In the past decade, considerable attention has been directed at an important class of biomolecules that function by binding to a wide variety of target molecules. Questions of current interest are: “Does the free biomolecule sample a conformational ensemble that encompasses the conformations found when it binds to various targets; and if so, on what time scale is the ensemble sampled?” This article reviews recent efforts to answer these questions, with a focus on comparing ensembles obtained for the same biomolecules by different investigators. A detailed comparison of results obtained is provided for three biomolecules: ubiquitin, calmodulin and the HIV-1 trans-activation response RNA. PMID:25669739

  19. Role Conflict and Conformity in Dress.

    ERIC Educational Resources Information Center

    Jasper, Cynthia R.; Roach-Higgins, Mary Ellen

    1988-01-01

    Examined conflict regarding what form of dress is appropriate for Roman Catholic priest. Data from 5,475 American Catholic priests revealed that priests who conformed to church regulations regarding dress differed from nonconformists in beliefs about their roles as priests and in their opinions of church reform, commitment to the priesthood,…

  20. Conformal symmetry of brane world effective actions

    SciTech Connect

    McFadden, Paul L.; Turok, Neil

    2005-01-15

    A simple derivation of the low-energy effective action for brane worlds is given, highlighting the role of conformal invariance. We show how to improve the effective action for a positive- and negative-tension brane pair using the AdS/CFT correspondence.

  1. Correcting mitochondrial fusion by manipulating mitofusin conformations

    PubMed Central

    Franco, Antonietta; Kitsis, Richard N.; Fleischer, Julie A.; Gavathiotis, Evripidis; Kornfeld, Opher S.; Gong, Guohua; Biris, Nikolaos; Benz, Ann; Qvit, Nir; Donnelly, Sara K; Chen, Yun; Mennerick, Steven; Hodgson, Louis; Mochly-Rosen, Daria; Dorn, Gerald W

    2017-01-01

    Summary Mitochondria are dynamic organelles, remodeling and exchanging contents during cyclic fusion and fission. Genetic mutations of mitofusin (Mfn) 2 interrupt mitochondrial fusion and cause the untreatable neurodegenerative condition, Charcot Marie Tooth disease type 2A (CMT2A). It has not been possible to directly modulate mitochondrial fusion, in part because the structural basis of mitofusin function is incompletely understood. Here we show that mitofusins adopt either a fusion-constrained or fusion-permissive molecular conformation directed by specific intramolecular binding interactions, and demonstrate that mitofusin-dependent mitochondrial fusion can be regulated by targeting these conformational transitions. Based on this model we engineered a cell-permeant minipeptide to destabilize fusion-constrained mitofusin and promote the fusion-permissive conformation, reversing mitochondrial abnormalities in cultured fibroblasts and neurons harboring CMT2A gene defects. The relationship between mitofusin conformational plasticity and mitochondrial dynamism uncovers a central mechanism regulating mitochondrial fusion whose manipulation can correct mitochondrial pathology triggered by defective or imbalanced mitochondrial dynamics. PMID:27775718

  2. Conformal Visualization for Partially-Immersive Platforms

    PubMed Central

    Petkov, Kaloian; Papadopoulos, Charilaos; Zhang, Min; Kaufman, Arie E.; Gu, Xianfeng

    2010-01-01

    Current immersive VR systems such as the CAVE provide an effective platform for the immersive exploration of large 3D data. A major limitation is that in most cases at least one display surface is missing due to space, access or cost constraints. This partially-immersive visualization results in a substantial loss of visual information that may be acceptable for some applications, however it becomes a major obstacle for critical tasks, such as the analysis of medical data. We propose a conformal deformation rendering pipeline for the visualization of datasets on partially-immersive platforms. The angle-preserving conformal mapping approach is used to map the 360°3D view volume to arbitrary display configurations. It has the desirable property of preserving shapes under distortion, which is important for identifying features, especially in medical data. The conformal mapping is used for rasterization, realtime raytracing and volume rendering of the datasets. Since the technique is applied during the rendering, we can construct stereoscopic images from the data, which is usually not true for image-based distortion approaches. We demonstrate the stereo conformal mapping rendering pipeline in the partially-immersive 5-wall Immersive Cabin (IC) for virtual colonoscopy and architectural review. PMID:26279083

  3. On the physical origin of galactic conformity

    NASA Astrophysics Data System (ADS)

    Hearin, Andrew P.; Behroozi, Peter S.; van den Bosch, Frank C.

    2016-09-01

    Correlations between the star formation rates (SFRs) of nearby galaxies (so-called galactic conformity) have been observed for projected separations up to 4 Mpc, an effect not predicted by current semi-analytic models. We investigate correlations between the mass accretion rates (dMvir/dt) of nearby haloes as a potential physical origin for this effect. We find that pairs of host haloes `know about' each others' assembly histories even when their present-day separation is greater than thirty times the virial radius of either halo. These distances are far too large for direct interaction between the haloes to explain the correlation in their dMvir/dt. Instead, halo pairs at these distances reside in the same large-scale tidal environment, which regulates dMvir/dt for both haloes. Larger haloes are less affected by external forces, which naturally gives rise to a mass dependence of the halo conformity signal. SDSS measurements of galactic conformity exhibit a qualitatively similar dependence on stellar mass, including how the signal varies with distance. Based on the expectation that halo accretion and galaxy SFR are correlated, we predict the scale-, mass- and redshift-dependence of large-scale galactic conformity, finding that the signal should drop to undetectable levels by z ≳ 1. These predictions are testable with current surveys to z ˜ 1; confirmation would establish a strong correlation between dark matter halo accretion rate and central galaxy SFR.

  4. A nonconforming multigrid method using conforming subspaces

    NASA Technical Reports Server (NTRS)

    Lee, Chang Ock

    1993-01-01

    For second-order elliptic boundary value problems, we develop a nonconforming multigrid method using the coarser-grid correction on the conforming finite element subspaces. The convergence proof with an arbitrary number of smoothing steps for nu-cycle is presented.

  5. Surveillance and Conformity in Competitive Youth Swimming

    ERIC Educational Resources Information Center

    Lang, Melanie

    2010-01-01

    Underpinned by a Foucauldian analysis of sporting practices, this paper identifies the disciplinary mechanism of surveillance at work in competitive youth swimming. It highlights the ways in which swimmers and their coaches are subject to and apply this mechanism to produce embodied conformity to normative behaviour and obedient, docile bodies.…

  6. Imbedding Locally Euclidean and Conformally Euclidean Metrics

    NASA Astrophysics Data System (ADS)

    Aleksandrov, V. A.

    1992-02-01

    The possibility of imbedding n-dimensional locally Euclidean metrics in the large in Rn is studied by means of the global inverse function theorem in the forms suggested by Hadamard, John, Levy and Plastock. The imbeddability of conformally Euclidean metrics is studied by means of a theorem of Zorich on the removability of an isolated singularity of a locally quasiconformal mapping.

  7. DFT CONFORMATIONAL STUDIES OF ALPHA-MALTOTRIOSE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recent DFT optimization studies on alpha-maltose improved our understanding of the preferred conformations of alpha-maltose and the present study extends these studies to alpha-maltotriose with three alpha-D-glucopyranose residues linked by two alpha-[1-4] bridges, denoted herein as DP-3's. Combina...

  8. 40 CFR 52.138 - Conformity procedures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... plans for metropolitan transportation planning organizations (MPOs) to use when determining conformity... levels above the standard. (5) Metropolitan planning organization (MPO) means the organization designated... described in 40 CFR 81.303 (i.e., the MAG urban planning area). (7) Transportation control measure...

  9. Design of conformal lens by drilling holes materials using quasi-conformal transformation optics.

    PubMed

    Li, Shouliang; Zhang, Zhan; Wang, Junhong; He, Xianshi

    2014-10-20

    In this paper, based on quasi-conformal transformation optics, a 3D conformal lens made of isotropic and non-resonant metamaterial is designed, which can make a cylindrical conformal array behave similarly to a uniform linear array. After discussion and simplification in the two-dimensional model, we realize the proposed lens by utilizing drilling-hole material in the three-dimensional structure. The ring-like shape and forward-only radiation make it possible to equip the lens on a cylindrical device.

  10. Isopermutation group

    SciTech Connect

    Muktibodh, A. S.

    2015-03-10

    The concept of ‘Isotopy’ as formulated by Ruggero Maria Santilli [1, 2, 3] plays a vital role in the development of Iso mathematics. Santilli defined iso-fields of characteristic zero. In this paper we extend this definition to define Iso-Galois fields [4] which are essentially of non-zero characteristic. Isotopically isomorphic realizations of a group define isopermutation group which gives a clear cut distinction between automorphic groups and isotopic groups.

  11. Testing of Advanced Conformal Ablative TPS

    NASA Technical Reports Server (NTRS)

    Gasch, Matthew; Agrawal, Parul; Beck, Robin

    2013-01-01

    In support of the CA250 project, this paper details the results of a test campaign that was conducted at the Ames Arcjet Facility, wherein several novel low density thermal protection (TPS) materials were evaluated in an entry like environment. The motivation for these tests was to investigate whether novel conformal ablative TPS materials can perform under high heat flux and shear environment as a viable alternative to rigid ablators like PICA or Avcoat for missions like MSL and beyond. A conformable TPS over a rigid aeroshell has the potential to solve a number of challenges faced by traditional rigid TPS materials (such as tiled Phenolic Impregnated Carbon Ablator (PICA) system on MSL, and honeycomb-based Avcoat on the Orion Multi Purpose Crew Vehicle (MPCV)). The compliant (high strain to failure) nature of the conformable ablative materials will allow better integration of the TPS with the underlying aeroshell structure and enable monolithic-like configuration and larger segments to be used in fabrication.A novel SPRITE1 architecture, developed by the researchers at NASA Ames was used for arcjet testing. This small probe like configuration with 450 spherecone, enabled us to test the materials in a combination of high heat flux, pressure and shear environment. The heat flux near the nose were in the range of 500-1000 W/sq cm whereas in the flank section of the test article the magnitudes were about 50 of the nose, 250-500W/sq cm range. There were two candidate conformable materials under consideration for this test series. Both test materials are low density (0.28 g/cu cm) similar to Phenolic Impregnated Carbon Ablator (PICA) or Silicone Impregnated Refractory Ceramic Ablator (SIRCA) and are comprised of: A flexible carbon substrate (Carbon felt) infiltrated with an ablative resin system: phenolic (Conformal-PICA) or silicone (Conformal-SICA). The test demonstrated a successful performance of both the conformable ablators for heat flux conditions between 50

  12. Mycobacterium tuberculosis acyl carrier protein synthase adopts two different pH-dependent structural conformations

    SciTech Connect

    Gokulan, Kuppan; Aggarwal, Anup; Shipman, Lance; Besra, Gurdyal S.; Sacchettini, James C.

    2011-07-01

    Bacterial acyl carrier protein synthase plays an essential role in the synthesis of fatty acids, nonribosomal peptides and polyketides. In Mycobacterium tuberculosis, AcpS or group I phosphopentatheine transferase exhibits two different structural conformations depending upon the pH. The crystal structures of acyl carrier protein synthase (AcpS) from Mycobacterium tuberculosis (Mtb) and Corynebacterium ammoniagenes determined at pH 5.3 and pH 6.5, respectively, are reported. Comparison of the Mtb apo-AcpS structure with the recently reported structure of the Mtb AcpS–ADP complex revealed that AcpS adopts two different conformations: the orthorhombic and trigonal space-group structures show structural differences in the α2 helix and in the conformation of the α3–α4 connecting loop, which is in a closed conformation. The apo-AcpS structure shows electron density for the entire model and was obtained at lower pH values (4.4–6.0). In contrast, at a higher pH value (6.5) AcpS undergoes significant conformational changes, resulting in disordered regions that show no electron density in the AcpS model. The solved structures also reveal that C. ammoniagenes AcpS undergoes structural rearrangement in two regions, similar to the recently reported Mtb AcpS–ADP complex structure. In vitro reconstitution experiments show that AcpS has a higher post-translational modification activity between pH 4.4 and 6.0 than at pH values above 6.5, where the activity drops owing to the change in conformation. The results show that apo-AcpS and AcpS–ADP adopt different conformations depending upon the pH conditions of the crystallization solution.

  13. Home Groups.

    ERIC Educational Resources Information Center

    Stahler, Theresa M.

    All students enrolled in the entry level foundations course in the College of Education of Kutztown University (Pennsylvania) participate in home groups, a cooperative learning strategy. Each student is assigned to a five- or six-person home group on the first day of class. Although group placements are made on the basis of class lists, every…

  14. The amide III vibrational circular dichroism band as a probe to detect conformational preferences of alanine dipeptide in water.

    PubMed

    Mirtič, Andreja; Merzel, Franci; Grdadolnik, Jože

    2014-07-01

    The conformational preferences of blocked alanine dipeptide (ADP), Ac-Ala-NHMe, in aqueous solution were studied using vibrational circular dichroism (VCD) together with density functional theory (DFT) calculations. DFT calculations of three most representative conformations of ADP surrounded by six explicit water molecules immersed in a dielectric continuum have proven high sensitivity of amide III VCD band shape that is characteristic for each conformation of the peptide backbone. The polyproline II (PII ) and αR conformation of ADP are associated with a positive VCD band while β conformation has a negative VCD band in amide III region. Knowing this spectral characteristic of each conformation allows us to assign the experimental amide III VCD spectrum of ADP. Moreover, the amide III region of the VCD spectrum was used to determine the relative populations of conformations of ADP in water. Based on the interpretation of the amide III region of VCD spectrum we have shown that dominant conformation of ADP in water is PII which is stabilized by hydrogen bonded water molecules between CO and NH groups on the peptide backbone.

  15. Enhanced conformational sampling using enveloping distribution sampling.

    PubMed

    Lin, Zhixiong; van Gunsteren, Wilfred F

    2013-10-14

    To lessen the problem of insufficient conformational sampling in biomolecular simulations is still a major challenge in computational biochemistry. In this article, an application of the method of enveloping distribution sampling (EDS) is proposed that addresses this challenge and its sampling efficiency is demonstrated in simulations of a hexa-β-peptide whose conformational equilibrium encompasses two different helical folds, i.e., a right-handed 2.7(10∕12)-helix and a left-handed 3(14)-helix, separated by a high energy barrier. Standard MD simulations of this peptide using the GROMOS 53A6 force field did not reach convergence of the free enthalpy difference between the two helices even after 500 ns of simulation time. The use of soft-core non-bonded interactions in the centre of the peptide did enhance the number of transitions between the helices, but at the same time led to neglect of relevant helical configurations. In the simulations of a two-state EDS reference Hamiltonian that envelops both the physical peptide and the soft-core peptide, sampling of the conformational space of the physical peptide ensures that physically relevant conformations can be visited, and sampling of the conformational space of the soft-core peptide helps to enhance the transitions between the two helices. The EDS simulations sampled many more transitions between the two helices and showed much faster convergence of the relative free enthalpy of the two helices compared with the standard MD simulations with only a slightly larger computational effort to determine optimized EDS parameters. Combined with various methods to smoothen the potential energy surface, the proposed EDS application will be a powerful technique to enhance the sampling efficiency in biomolecular simulations.

  16. The preferred all-gauche conformations in 3-fluoro-1,2-propanediol.

    PubMed

    Andrade, Laize A F; Silla, Josué M; Duarte, Claudimar J; Rittner, Roberto; Freitas, Matheus P

    2013-10-21

    A competition between the terminal fluorine and hydroxyl groups by the central hydroxyl group as hydrogen bond donor in 3-fluoro-1,2-propanediol would be expected to dictate the conformational isomerism of this compound, but also the repulsion between the electronegative and bulky vicinal substituents. Indeed, an intramolecular hydrogen bond has been verified only for a local minimum using QTAIM calculations, while the most stable conformer exhibits an all-gauche conformation with a small stabilizing contribution from the nF→σ interaction. The preferred orientation of the OH and F substituents was confirmed from the chemical shifts and coupling constants of the diastereotopic hydrogens. This conformational preference, which is calculated to exist both in the gas phase and solution (using implicit CHCl3 and CH3CN solvents), is better described by predominant hyperconjugative interactions over Lewis-type interactions. The strong contribution from antiperiplanar interactions involving σCH and σCC as electron donors and σ and σ as electron acceptors dictates the gauche effect in 3-fluoro-1,2-propanediol rather than a hydrogen bond. The absence of JF,H(O) and JH(O),H(O) coupling constants confirms that any influence from a hydrogen bond to the conformational isomerism of 3-fluoro-1,2-propanediol is secondary.

  17. Galaxy groups

    SciTech Connect

    Brent Tully, R.

    2015-02-01

    Galaxy groups can be characterized by the radius of decoupling from cosmic expansion, the radius of the caustic of second turnaround, and the velocity dispersion of galaxies within this latter radius. These parameters can be a challenge to measure, especially for small groups with few members. In this study, results are gathered pertaining to particularly well-studied groups over four decades in group mass. Scaling relations anticipated from theory are demonstrated and coefficients of the relationships are specified. There is an update of the relationship between light and mass for groups, confirming that groups with mass of a few times 10{sup 12}M{sub ⊙} are the most lit up while groups with more and less mass are darker. It is demonstrated that there is an interesting one-to-one correlation between the number of dwarf satellites in a group and the group mass. There is the suggestion that small variations in the slope of the luminosity function in groups are caused by the degree of depletion of intermediate luminosity systems rather than variations in the number per unit mass of dwarfs. Finally, returning to the characteristic radii of groups, the ratio of first to second turnaround depends on the dark matter and dark energy content of the universe and a crude estimate can be made from the current observations of Ω{sub matter}∼0.15 in a flat topology, with a 68% probability of being less than 0.44.

  18. Conformational analysis and vibrational assignments of benzohydroxamic acid and benzohydrazide

    NASA Astrophysics Data System (ADS)

    Al-Saadi, Abdulaziz A.

    2012-09-01

    The structures of benzohydroxamic acid (BHA) and benzohydrazide (BH) were investigated at the B3LYP, MP2 and MP4(SDQ) levels of theory and compared to the corresponding structures of formyl analogs. All levels of theory predicted the two molecules to exist predominantly in a near-planar structure adopting a cis conformation where the hydroxyl group of the acid and the amino group of the hydrazide eclipse the carbonyl bond. The stability of the near-planar structure is explained on the basis of mutual conjugation between the phenyl and the Nsbnd H moieties with the Cdbnd O group. The intramolecular interaction between the carbonyl group and the hydrogen atom of the hydroxyl group of the acid or the amino group of the hydrazide plays a significant role in stabilizing the near-cis form in both molecules. The degree of the non-planarity was predicted to increase as going from BHA to BH molecules. The computed vibrational frequencies of the near-cis structure were combined with experimental infrared and Raman data to provide reliable vibrational assignments for the two molecules.

  19. Conformational analysis of oligosaccharides and polysaccharides using molecular dynamics simulations.

    PubMed

    Frank, Martin

    2015-01-01

    Complex carbohydrates usually have a large number of rotatable bonds and consequently a large number of theoretically possible conformations can be generated (combinatorial explosion). The application of systematic search methods for conformational analysis of carbohydrates is therefore limited to disaccharides and trisaccharides in a routine analysis. An alternative approach is to use Monte-Carlo methods or (high-temperature) molecular dynamics (MD) simulations to explore the conformational space of complex carbohydrates. This chapter describes how to use MD simulation data to perform a conformational analysis (conformational maps, hydrogen bonds) of oligosaccharides and how to build realistic 3D structures of large polysaccharides using Conformational Analysis Tools (CAT).

  20. Binding Affinities Controlled by Shifting Conformational Equilibria: Opportunities and Limitations

    PubMed Central

    Michielssens, Servaas; de Groot, Bert L.; Grubmüller, Helmut

    2015-01-01

    Conformational selection is an established mechanism in molecular recognition. Despite its power to explain binding events, it is hardly used in protein/ligand design to modulate molecular recognition. Here, we explore the opportunities and limitations of design by conformational selection. Using appropriate thermodynamic cycles, our approach predicts the effects of a conformational shift on binding affinity and also allows one to disentangle the effects induced by a conformational shift from other effects influencing the binding affinity. The method is assessed and applied to explain the contribution of a conformational shift on the binding affinity of six ubiquitin mutants showing different conformational shifts in six different complexes. PMID:25992736

  1. Black hole temperature: Minimal coupling vs conformal coupling

    SciTech Connect

    Fazel, Mohamadreza; Mirza, Behrouz; Mansoori, Seyed Ali Hosseini

    2014-05-15

    In this article, we discuss the propagation of scalar fields in conformally transformed spacetimes with either minimal or conformal coupling. The conformally coupled equation of motion is transformed into a one-dimensional Schrödinger-like equation with an invariant potential under conformal transformation. In a second stage, we argue that calculations based on conformal coupling yield the same Hawking temperature as those based on minimal coupling. Finally, it is conjectured that the quasi normal modes of black holes are invariant under conformal transformation.

  2. Conformational Equilibrium of N-Myristoylated cAMP-Dependent Protein Kinase A by Molecular Dynamics Simulations

    PubMed Central

    Cembran, Alessandro; Masterson, Larry R.; McClendon, Christopher L.; Taylor, Susan S.; Gao, Jiali; Veglia, Gianluigi

    2013-01-01

    The catalytic subunit of protein kinase A (PKA-C) is subject to several post- or co-translational modifications that regulate its activity both spatially and temporally. Among those, N-myristoylation increases the kinase affinity for membranes and might also be implicated in substrate recognition and allosteric regulation. Here, we investigated the effects of N-myristoylation on the structure, dynamics, and conformational equilibrium of PKA-C using atomistic molecular dynamics simulations. We found that the myristoyl group inserts into the hydrophobic pocket and leads to a tighter packing of the A-helix against the core of the enzyme. As a result, the A-helix conformational dynamics are reduced and its motions are more coupled with the active site. Our simulations suggest that cation-π interactions between W30, R190, and R93 are responsible for coupling these motions. Two major conformations of the myristoylated N-terminus are the most populated: a long loop (LL conformation), similar to PDB:1CMK, and a helix-turn-helix (HTH conformation), similar to PDB:4DFX, which shows stronger coupling between the conformational dynamics observed at the A-helix and active site. The HTH conformation is stabilized by S10 phosphorylation of the kinase via ionic interactions between the protonated amine of K7 and the phosphate group on S10, further enhancing the dynamic coupling to the active site. These results support a role of N-myristoylation in the allosteric regulation of PKA-C. PMID:23205665

  3. Is there a general rule for the gauche effect in the conformational isomerism of 1,2-disubstituted ethanes?

    PubMed

    Freitas, Matheus P; Rittner, Roberto

    2007-08-02

    The stabilities of the gauche and anti conformations of butane, 1,2-dicyanoethane (DCE), and 1,2-dinitroethane (DNE) have been investigated through theoretical calculations. The gauche effect-the tendency of keeping close vicinal electronegative substituents (thetaX-C-C-X approximately 60 degrees ) in an ethane fragment-is expected to drive the conformational equilibrium of DCE and DNE toward the gauche conformation. It was found that, for butane, where the gauche effect is supposed to be poor/null, the hyperconjugation effect contributes mostly to the anti stabilization in opposition to the traditional sense that the methyl groups repel each other, and this should govern its conformational equilibrium. For DCE the equilibrium was shifted to the anti conformer, essentially due to a gauche repulsion, while for DNE, despite the higher electronic delocalization energies, a predominance of the gauche conformer was obtained, and this was attributed mainly to the attractive dipolar interaction between the two nitro groups. A full orbital energy analysis was performed using the natural bond orbital approach, which showed that bond bending and anti-C-H/C-X* hyperconjugation models, usually applied to explain the origin of the gauche effect in fluorinated derivatives, are not adequate to completely explain the conformational behavior of the titled compounds.

  4. Maillard glycation of beta-lactoglobulin induces conformation changes.

    PubMed

    Chevalier, F; Chobert, J M; Dalgalarrondo, M; Choiset, Y; Haertlé, T

    2002-04-01

    Glycation by the Maillard reaction is an ubiquitous reaction of condensation of a reducing sugar with amino groups of proteins, which products could improve the functional and/or biological properties for food and non-food uses. It can induce structural modifications in proteins, modifying their properties. The aim of this work was to investigate the association behavior and the conformational changes of beta-lactoglobulin (BLG) after its glycation by the Maillard reaction with several alimentary sugars (arabinose, galactose, glucose, lactose, rhamnose and ribose). Protein samples were heated in the presence or in the absence (heated control) of different sugars during 3 days at 60 degrees C. Glycation induced oligomerization of BLG monomers. Depending on the reactivity of the sugar, the population of produced oligomers showed smaller or greater heterogeneity in molecular masses. Analysis of modified BLG by circular dichroism and by its susceptibility to pepsinolysis showed that the conditions of heating used did not significantly alter the conformation of BLG. Heating of BLG in presence of sugars induced only minor structural modification, when using the less reactive sugars such as lactose and rhamnose. It was, however, at the origin of major three-dimensional destructuring in the case of the more reactive sugars such as arabinose and ribose. Pepsinolysis of glycated BLG did not affect about 62 and 35% of the protein molecules modified with lactose or rhamnose, and arabinose or ribose, respectively. The increase of susceptibility of glycated BLG to pepsinolysis could be related to the alteration of the conformation of the protein when glycation was performed with highly reactive sugars, as observed by circular dichroism and calorimetry analysis.

  5. GROUP INEQUALITY

    PubMed Central

    Bowles, Samuel; Loury, Glenn C.; Sethi, Rajiv

    2014-01-01

    We explore the combined effect of segregation in social networks, peer effects, and the relative size of a historically disadvantaged group on the incentives to invest in market-rewarded skills and the dynamics of inequality between social groups. We identify conditions under which group inequality will persist in the absence of differences in ability, credit constraints, or labor market discrimination. Under these conditions, group inequality may be amplified even if initial group differences are negligible. Increases in social integration may destabilize an unequal state and make group equality possible, but the distributional and human capital effects of this depend on the demographic composition of the population. When the size of the initially disadvantaged group is sufficiently small, integration can lower the long-run costs of human capital investment in both groups and result in an increase the aggregate skill share. In contrast, when the initially disadvantaged group is large, integration can induce a fall in the aggregate skill share as the costs of human capital investment rise in both groups. We consider applications to concrete cases and policy implications. PMID:25554727

  6. Conformity of Behaviors among Medical Students: Impact on Performance of Knee Arthrocentesis in Simulation

    ERIC Educational Resources Information Center

    Beran, Tanya N.; McLaughlin, Kevin; Al Ansari, Ahmed; Kassam, Aliya

    2013-01-01

    Although the development of collaborative relationships is considered a requirement for medical education, the functioning of these relationships may be impaired by a well-documented social-psychological phenomenon known as group conformity. The authors hypothesized that students would insert a needle into an incorrect location relative to the…

  7. Children's Gender Identity Development: The Dynamic Negotiation Process between Conformity and Authenticity

    ERIC Educational Resources Information Center

    Brinkman, Britney G; Rabenstein, Kelly L.; Rosén, Lee A.; Zimmerman, Toni S.

    2014-01-01

    In the current study, 45 girls and 41 boys participated in focus groups following a program designed to teach them about social justice. The children articulated the discrepancy between their own gender identity and gender role stereotypes and discussed potential problems with conforming to gender role expectations as well as consequences of…

  8. A Latent Class Regression Analysis of Men's Conformity to Masculine Norms and Psychological Distress

    ERIC Educational Resources Information Center

    Wong, Y. Joel; Owen, Jesse; Shea, Munyi

    2012-01-01

    How are specific dimensions of masculinity related to psychological distress in specific groups of men? To address this question, the authors used latent class regression to assess the optimal number of latent classes that explained differential relationships between conformity to masculine norms and psychological distress in a racially diverse…

  9. Quasi-conformal shape of the BFKL kernel and impact factors for scattering of colourless particles

    NASA Astrophysics Data System (ADS)

    Fadin, V. S.; Fiore, R.; Grabovsky, A. V.; Papa, A.

    2011-07-01

    The NLO BFKL kernel in the Möbius representation is transformed to the quasi-conformal shape in theories containing fermions and scalars in arbitrary representations of the colour group. Corresponding transformations of impact factors of colourless particles are discussed.

  10. Whitehead Groups of Spinor Groups

    NASA Astrophysics Data System (ADS)

    Monastyrnyĭ, A. P.; Yanchevskiĭ, V. I.

    1991-02-01

    The Whitehead groups of spinor groups are studied. The known Kneser-Tits conjecture for spinor groups is reduced to a spinor analogue of the Tannaka-Artin problem, namely, to the question of whether the group K1Spin(D), where D is a division ring of exponent 2 , is trivial. A counterexample to the Kneser-Tits problem is constructed in the class of spinor groups. The group K1Spin(D) is computed. The stability of the Whitehead groups of spinor groups under purely transcendental extensions of the ground field is established. The R-equivalence on the k-points of spinor groups and the weak approximation problem are considered. The study of spinor group completes the study of the Whitehead groups of algebraic groups of classical type, that was started in studying reduced K-theory (V.P. Platonov) and was continued for reduced unitary K-theory (V.I. Yanchevskiĭ) and Hermitian K-theory (Platonov and Yanchevskiĭ). Bibliography: 50 titles.

  11. Conformation of some N,N'-arylalkyl thioureas by 1H-NMR and infrared spectral analysis

    NASA Astrophysics Data System (ADS)

    Sudha, L. V.; Sathyanarayana, D. N.

    Several N,N'-arylalkyl thioureas were examined with 1H-NMR and i.r. spectra in order to study the conformation of the -NHCSNH- group. The influence of temperature and substituents on the chemical shift of the NH protons has been investigated. Formation of a strong intramolecular hydrogen bond stabilizes the trans—cis conformation for most systems, while for the others the prevalence of different rotational isomers can be postulated. The influence of the steric effect on hydrogen bonding and molecular conformation is discussed.

  12. Reactions driving conformational movements (molecular motors) in gels: conformational and structural chemical kinetics.

    PubMed

    Otero, Toribio F

    2017-01-18

    In this perspective the empirical kinetics of conducting polymers exchanging anions and solvent during electrochemical reactions to get dense reactive gels is reviewed. The reaction drives conformational movements of the chains (molecular motors), exchange of ions and solvent with the electrolyte and structural (relaxation, swelling, shrinking and compaction) gel changes. Reaction-driven structural changes are identified and quantified from electrochemical responses. The empirical reaction activation energy (Ea), the reaction coefficient (k) and the reaction orders (α and β) change as a function of the conformational energy variation during the reaction. This conformational energy becomes an empirical magnitude. Ea, k, α and β include and provide quantitative conformational and structural information. The chemical kinetics becomes structural chemical kinetics (SCK) for reactions driving conformational movements of the reactants. The electrochemically stimulated conformational relaxation model describes empirical results and some results from the literature for biochemical reactions. In parallel the development of an emerging technological world of soft, wet, multifunctional and biomimetic tools and anthropomorphic robots driven by reactions of the constitutive material, as in biological organs, can be now envisaged being theoretically supported by the kinetic model.

  13. The conformation of a B-DNA decamer is mainly determined by its sequence and not by crystal environment.

    PubMed Central

    Heinemann, U; Alings, C

    1991-01-01

    By comparing the conformations adopted by a double-stranded decameric B-DNA fragment in different crystal environments, we address the question of the degree of deformability of DNA helices. The three-dimensional structure of the self-complementary DNA decamer CCAGGCmeCTGG has been determined from crystals of space group P6 at 2.25 A resolution with an R value of 17.2% for 2407 1 sigma structure amplitudes. The oligonucleotide forms a B-type double helix with a characteristic sequence-dependent conformation closely resembling that of the corresponding unmethylated decamer, the structure of which is known from a high-resolution analysis of crystals of space group C2. Evidently, both the effects of single-site methylation and altered crystal environment on the DNA conformation are small. Therefore, double-helical DNA may possess sequence-determined conformational features that are less deformable than previously thought. Images PMID:1989887

  14. The role of nonbonding interactions and the presence of fluoride on the conformational isomerism of 1,2-ethanediol

    NASA Astrophysics Data System (ADS)

    Silva, Weslley G. D. P.; Silla, Josué M.; Cormanich, Rodrigo A.; Fernandes, Sergio A.; Freitas, Matheus P.

    2016-07-01

    This work reports the analysis of the effects ruling the conformational preference of 1,2-ethanediol (1,2-ED) using theoretical calculations, since there is no general consensus about the role of intramolecular hydrogen bond on the conformational isomerism of 1,2-ED. While the predominance of the gauche conformers along with the Osbnd Csbnd Csbnd O fragment relative to the trans ones was found to be mainly due to hyperconjugation, the orientation of the hydroxyl groups is better described by a balance between low steric hindrance and high stabilization from hyperconjugation than by intramolecular hydrogen bond. Nevertheless, the presence of a fluoride anion induces a conformational change in 1,2-ED that maximizes hydrogen bonds between the fluoride and the hydroxyl groups. This effect was observed experimentally by the shift of 1H(O) and 19F NMR signals upon complexation, then suggesting that compounds containing the 1,2-ED moiety can be possible anion transporters.

  15. Testing Conformal Theory:. 3-STATE Potts

    NASA Astrophysics Data System (ADS)

    Barkema, G. T.; McCabe, J.; Wydro, T.

    2001-04-01

    Conformal theory predictions and Monte Carlo measurements of structure constants in 3-state Potts model were reviewed. The results provide a direct confirmation of the quality of conformal theory predictions of universal 3-point amplitudes. The prediction of these type of universal amplitudes sparked much of the original interest in conformal models, but are almost untested outside of the Ising model. Structure constants, C123, are universal amplitudes that define 3-point correlations, i.e., <∫1(X1)∫2(X2) ∫3(X3)+> = C123/ |X12|2(Δ1+Δ2-Δ3)·× cyclic perms. To predict the values of these universal numbers, one constructs a 4-point correlation as a sum of products of conformal blocks and then, determines coefficients that weight the sum by demanding that the 4-point correlation satisfy a bootstrap equation. The bootstrap equation imposes consistency of the 4-point correlation with operator product expansions in multiple channels. The 3-state Potts model was chosen, because this model is easy of simulate. But, this Potts model has an added complication, i.e., a discrete Z3 symmetry at criticality. The discrete symmetry had to be implemented to calculate structure constants. Conformal theory predicted that Cσσσ = 1.092 and Cɛσσ* = 0.546. Monte Carlo simulations were performed on 500 × 500 lattices on which sample configurations were generated by the cluster algorithm of Wolff. To obtain the structure constants both 2-point and 3-point correlations were measured. The 2-point correlations fixed non-universal normalizatons. The quality of the Monte-Carlo methods were tested by measuring structure constants of the Ising model-good agreement with known results was found. For 3-state Potts, the simulations found that Cσσσ = 1.116 ± 0.14 and Cɛσσ* = 0.61 ± 0.06. These results provide striking agreement with predictions and a confirmation of conformal field theory.

  16. Conformational behavior of flavin adenine dinucleotide: conserved stereochemistry in bound and free states.

    PubMed

    Kuppuraj, Gopi; Kruise, Dennis; Yura, Kei

    2014-11-26

    Metabolic enzymes utilize the cofactor flavin adenine dinucleotide (FAD) to catalyze essential biochemical reactions. Because these enzymes have been implicated in disease pathways, it will be necessary to target them via FAD-based structural analogues that can either activate/inhibit the enzymatic activity. To achieve this, it is important to explore the conformational space of FAD in the enzyme-bound and free states. Herein, we analyze X-ray crystallographic data of the enzyme-bound FAD conformations and sample conformations of the molecule in explicit water by molecular dynamics (MD) simulations. Enzyme-bound FAD conformations segregate into five distinct groups based on dihedral angle principal component analysis (PCA). A notable feature in the bound FADs is that the adenine base and isoalloxazine ring are oppositely oriented relative to the pyrophosphate axis characterized by near trans hypothetical dihedral angle "δV" values. Not surprisingly, MD simulations in water show final compact but not perfectly stacked ring structures in FAD. Simulation data did not reveal noticeable changes in overall conformational dynamics of the dinucleotide in reduced and oxidized forms and in the presence and/or absence of ions. During unfolding-folding dynamics, the riboflavin moiety is more flexible than the adenosine monophosphate group in the molecule. Conversely, the isoalloxazine ring is more stable than the variable adenine base. The pyrophosphate group depicts an unusually highly organized fluctuation illustrated by its dihedral angle distribution. Conformations sampled from enzymes and MD are quantified. The extent to which the protein shifts the distribution from the unbound state is discussed in terms of prevalent FAD shapes and dihedral angle population.

  17. Conformational analysis of small molecules: NMR and quantum mechanics calculations.

    PubMed

    Tormena, Cláudio F

    2016-08-01

    This review deals with conformational analysis in small organic molecules, and describes the stereoelectronic interactions responsible for conformational stability. Conformational analysis is usually performed using NMR spectroscopy through measurement of coupling constants at room or low temperature in different solvents to determine the populations of conformers in solution. Quantum mechanical calculations are used to address the interactions responsible for conformer stability. The conformational analysis of a large number of small molecules is described, using coupling constant measurements in different solvents and at low temperature, as well as recent applications of through-space and through-hydrogen bond coupling constants JFH as tools for the conformational analysis of fluorinated molecules. Besides NMR parameters, stereoelectronic interactions such as conjugative, hyperconjugative, steric and intramolecular hydrogen bond interactions involved in conformational preferences are discussed.

  18. Conformal invariance and Hamilton Jacobi theory for dissipative systems

    NASA Technical Reports Server (NTRS)

    Kiehn, R. M.

    1975-01-01

    For certain dissipative systems, a comparison can be made between the Hamilton-Jacobi theory and the conformal invariance of action theory. The two concepts are not identical, but the conformal action theory covers the Hamilton-Jacobi theory.

  19. Epistemic motives and cultural conformity: need for closure, culture, and context as determinants of conflict judgments.

    PubMed

    Fu, Jeanne Ho-ying; Morris, Michael W; Lee, Sau-lai; Chao, Melody; Chiu, Chi-yue; Hong, Ying-yi

    2007-02-01

    Three studies support the proposal that need for closure (NFC) involves a desire for consensual validation that leads to cultural conformity. Individual differences in NFC interact with cultural group variables to determine East Asian versus Western differences in conflict style and procedural preferences (Study 1), information gathering in disputes (Study 2), and fairness judgment in reward allocations (Study 3). Results from experimental tests indicate that the relevance of NFC to cultural conformity reflects consensus motives rather than effort minimization (Study 2) or political conservatism (Study 3). Implications for research on conflict resolution and motivated cultural cognition are discussed.

  20. (1)H chemical shift differences of Prelog-Djerassi lactone derivatives: DFT and NMR conformational studies.

    PubMed

    Aímola, Túlio J; Lima, Dimas J P; Dias, Luiz C; Tormena, Cláudio F; Ferreira, Marco A B

    2015-02-21

    This work reports an experimental and theoretical study of the conformational preferences of several Prelog-Djerassi lactone derivatives, to elucidate the (1)H NMR chemical shift differences in the lactonic core that are associated with the relative stereochemistry of these derivatives. The boat-like conformation of explains the anomalous (1)H chemical shift between H-5a and H-5b, in which the two methyl groups (C-8 and C-9) face H-5b, leading to its higher shielding effect.

  1. Rational Conformal Correlation Functions of Gauge-Invariant Local Fields in Four Dimensions

    SciTech Connect

    Nikolov, N.M.; Stanev, Ya.S.; Todorov, I.T.

    2005-11-01

    Global conformal invariance in Minkowski space and the Wightman axioms imply strong locality (Huygens principle) and rationality of correlation functions, thus providing an extension of the concept of a vertex algebra to higher (even) dimensions D. We (p)review current work on a model of a Hermitian scalar field L of scale dimension 4 (D = 4) which can be interpreted as the Lagrangian of a gauge field theory that generates the algebra of gauge-invariant local observables in a conformally invariant renormalization group fixed point.

  2. Spinor product computations for protein conformations.

    PubMed

    Chys, Pieter; Chacón, Pablo

    2012-08-05

    Spinor operators in geometric algebra (GA) can efficiently describe conformational changes of proteins by ordered products that act on individual bonds and represent their net rotations. Backward propagation through the protein backbone yields all rotational spinor axes in advance allowing the efficient computation of atomic coordinates from internal coordinates. The introduced mathematical framework enables to efficiently manipulate and generate protein conformations to any arbitrary degree. Moreover, several new formulations in the context of rigid body motions are added. Emphasis is placed on the intimate relationship between spinors and quaternions, which can be recovered from within the GA approach. The spinor methodology is implemented and tested versus the state of the art algorithms for both protein construction and coordinate updating. Spinor calculations have a smaller computational cost and turn out to be slightly faster than current alternatives.

  3. Conformational flexibility of bacterial RNA polymerase

    PubMed Central

    Darst, Seth A.; Opalka, Natacha; Chacon, Pablo; Polyakov, Andrey; Richter, Catherine; Zhang, Gongyi; Wriggers, Willy

    2002-01-01

    The structure of Escherichia coli core RNA polymerase (RNAP) was determined by cryo-electron microscopy and image processing of helical crystals to a nominal resolution of 15 Å. Because of the high sequence conservation between the core RNAP subunits, we were able to interpret the E. coli structure in relation to the high-resolution x-ray structure of Thermus aquaticus core RNAP. A very large conformational change of the T. aquaticus RNAP x-ray structure, corresponding to opening of the main DNA/RNA channel by nearly 25 Å, was required to fit the E. coli map. This finding reveals, at least partially, the range of conformational flexibility of the RNAP, which is likely to have functional implications for the initiation of transcription, where the DNA template must be loaded into the channel. PMID:11904365

  4. The conformational musings of a medicinal chemist.

    PubMed

    Finch, Harry

    2014-03-01

    Structure-based drug design strategies based on X-ray crystallographic data of ligands bound to biological targets or computationally derived pharmacophore models have been introduced over the past 25 years or so. These have now matured and are deeply embedded in the drug discovery process in most pharmaceutical and biotechnology companies where they continue to play a major part in the discovery of new medicines and drug candidates. Newly developed NMR methods can now provide a full description of the conformations in which ligands exist in free solution, crucially allowing those that are dominant to be identified. Integrating experimentally determined conformational information on active and inactive molecules in drug discovery programmes, alongside the existing techniques, should have a major impact on the success of drug discovery.

  5. Chromosome Conformation Capture in Primary Human Cells.

    PubMed

    Cortesi, Alice; Bodega, Beatrice

    2016-01-01

    3D organization of the genome, its structural and regulatory function of cell identity, is acquiring prominent features in epigenetics studies; more efforts have been done to develop techniques that allow studying nuclear structure. Chromosome conformation capture (3C) has been set up in 2002 from Dekker and from that moment great investments were made to develop genomics variants of 3C technology (4C, 5C, Hi-C) providing new tools to investigate the shape of the genome in a more systematic and unbiased manner. 3C method allows scientists to fix dynamic and variable 3D interactions in nuclear space, and consequently to study which sequences interact, how a gene is regulated by different and distant enhancer, or how a set of enhancer could regulate transcriptional units; to follow the conformation that mediates regulation change in development; and to evaluate if this fine epigenetic mechanism is impaired in disease condition.

  6. Impacts of Conformational Geometries in Fluorinated Alkanes

    NASA Astrophysics Data System (ADS)

    Brandenburg, Tim; Golnak, Ronny; Nagasaka, Masanari; Atak, Kaan; Sreekantan Nair Lalithambika, Sreeju; Kosugi, Nobuhiro; Aziz, Emad F.

    2016-08-01

    Research of blood substitute formulations and their base materials is of high scientific interest. Especially fluorinated microemulsions based on perfluorocarbons, with their interesting chemical properties, offer opportunities for applications in biomedicine and physical chemistry. In this work, carbon K-edge absorption spectra of liquid perfluoroalkanes and their parent hydrocarbons are presented and compared. Based on soft X-ray absorption, a comprehensive picture of the electronic structure is provided with the aid of time dependent density functional theory. We have observed that conformational geometries mainly influence the chemical and electronic interactions in the presented liquid materials, leading to a direct association of conformational geometries to the dissolving capacity of the presented perfluorocarbons with other solvents like water and possibly gases like oxygen.

  7. Conformal anomaly around the sudden singularity

    NASA Astrophysics Data System (ADS)

    Houndjo, S. J. M.

    2010-10-01

    Quantum effects due to particle creation on a classical sudden singularity have been investigated in a previous work. The conclusion was that quantum effects do not lead to the avoidance nor the modification of the sudden future singularity. In this paper, we investigate quantum corrections coming from conformal anomaly near the sudden future singularity. We conclude that when the equation of state is chosen to be p=-ρ-Aρα, the conformal anomaly can transform the sudden singularity into the singularity of type III for any α>1/2 and into the singularity of the type I (the big rip) or the big crunch for 1/2<α<3/2.

  8. Conformation-controlled binding kinetics of antibodies

    PubMed Central

    Galanti, Marta; Fanelli, Duccio; Piazza, Francesco

    2016-01-01

    Antibodies are large, extremely flexible molecules, whose internal dynamics is certainly key to their astounding ability to bind antigens of all sizes, from small hormones to giant viruses. In this paper, we build a shape-based coarse-grained model of IgG molecules and show that it can be used to generate 3D conformations in agreement with single-molecule Cryo-Electron Tomography data. Furthermore, we elaborate a theoretical model that can be solved exactly to compute the binding rate constant of a small antigen to an IgG in a prescribed 3D conformation. Our model shows that the antigen binding process is tightly related to the internal dynamics of the IgG. Our findings pave the way for further investigation of the subtle connection between the dynamics and the function of large, flexible multi-valent molecular machines. PMID:26755272

  9. Initial conformation of kinesin's neck linker

    NASA Astrophysics Data System (ADS)

    Geng, Yi-Zhao; Ji, Qing; Liu, Shu-Xia; Yan, Shi-Wei

    2014-10-01

    How ATP binding initiates the docking process of kinesin's neck linker is a key question in understanding kinesin mechanisms. By exploiting a molecular dynamics method, we investigate the initial conformation of kinesin's neck linker in its docking process. We find that, in the initial conformation, the neck linker has interactions with β0 and forms a ‘cover-neck bundle’ structure with β0. From this initial structure, the formation of extra turns and the docking of the cover-neck bundle structure can be achieved. The motor head provides a forward force on the initial cover-neck bundle structure through ATP-induced rotation. This force, together with the hydrophobic interaction of ILE327 with the hydrophobic pocket on the motor head, drives the formation of the extra turn and initiates the neck linker docking process. Based on these findings, a pathway from ATP binding-induced motor head rotation to neck linker docking is proposed.

  10. Appendage mountable electronic devices conformable to surfaces

    DOEpatents

    Rogers, John; Ying, Ming; Bonifas, Andrew; Lu, Nanshu

    2017-01-24

    Disclosed are appendage mountable electronic systems and related methods for covering and conforming to an appendage surface. A flexible or stretchable substrate has an inner surface for receiving an appendage, including an appendage having a curved surface, and an opposed outer surface that is accessible to external surfaces. A stretchable or flexible electronic device is supported by the substrate inner and/or outer surface, depending on the application of interest. The electronic device in combination with the substrate provides a net bending stiffness to facilitate conformal contact between the inner surface and a surface of the appendage provided within the enclosure. In an aspect, the system is capable of surface flipping without adversely impacting electronic device functionality, such as electronic devices comprising arrays of sensors, actuators, or both sensors and actuators.

  11. The Kinetics of Forisome Conformation Change

    NASA Astrophysics Data System (ADS)

    Warmann, Stephen; Pickard, William

    2005-11-01

    Forisomes are a newly discovered proteinaceous contractile element found in the phloem of legumes. These protein bodies show promise as a biological smart material. Forisomes contract anisotropically in response to pH variation or the presence of calcium ions. Possible applications of forisomes include micro-valves, micro-actuators, and other smart sensing activities where one may currently see materials such as synthetic hydrogels or shape memory alloys. In order to pursue forisome synthesis as a smart material and to understand the biological function of the forisome, a detailed understanding of its material properties is necessary. Our research in this area entails the study of the mechanical properties and surface interactions of forisomes. Here we present detailed conformational kinetics of forisomes from Vicia faba, Glycine max, and Canavalia gladiata. The flow rate dependency of conformational kinetics within a microfluidic network is described. Computational fluid dynamic models of the phloem are presented.

  12. Radiosurgical planning of meningiomas: compromises with conformity.

    PubMed

    Rowe, Jeremy G; Walton, Lee; Vaughan, Paul; Malik, Irfan; Radatz, Matthias; Kemeny, Andras

    2004-01-01

    The radiosurgical planning of meningiomas frequently necessitates compromises between irradiating tumour and risking damage to adjacent structures. In selected cases, we resolved this by excluding part of the tumour from the prescription isodose volume. Most of these compromises or 'suboptimal' plans achieved growth control. Growth control could not be related to conformity indices or to various measures of the radiation dose received by the meningioma. Examining recurrences, 75% arose from dura outside the original treatment field. These findings are discussed in terms of dose prescription protocols and the use of conformity indices in planning. The importance of the dural origin of meningiomas is well established in surgical practice, as reflected by Simpson's grades, but may be equally significant in radiosurgical practice.

  13. Conformation-controlled binding kinetics of antibodies

    NASA Astrophysics Data System (ADS)

    Galanti, Marta; Fanelli, Duccio; Piazza, Francesco

    2016-01-01

    Antibodies are large, extremely flexible molecules, whose internal dynamics is certainly key to their astounding ability to bind antigens of all sizes, from small hormones to giant viruses. In this paper, we build a shape-based coarse-grained model of IgG molecules and show that it can be used to generate 3D conformations in agreement with single-molecule Cryo-Electron Tomography data. Furthermore, we elaborate a theoretical model that can be solved exactly to compute the binding rate constant of a small antigen to an IgG in a prescribed 3D conformation. Our model shows that the antigen binding process is tightly related to the internal dynamics of the IgG. Our findings pave the way for further investigation of the subtle connection between the dynamics and the function of large, flexible multi-valent molecular machines.

  14. Impacts of Conformational Geometries in Fluorinated Alkanes

    PubMed Central

    Brandenburg, Tim; Golnak, Ronny; Nagasaka, Masanari; Atak, Kaan; Sreekantan Nair Lalithambika, Sreeju; Kosugi, Nobuhiro; Aziz, Emad F.

    2016-01-01

    Research of blood substitute formulations and their base materials is of high scientific interest. Especially fluorinated microemulsions based on perfluorocarbons, with their interesting chemical properties, offer opportunities for applications in biomedicine and physical chemistry. In this work, carbon K-edge absorption spectra of liquid perfluoroalkanes and their parent hydrocarbons are presented and compared. Based on soft X-ray absorption, a comprehensive picture of the electronic structure is provided with the aid of time dependent density functional theory. We have observed that conformational geometries mainly influence the chemical and electronic interactions in the presented liquid materials, leading to a direct association of conformational geometries to the dissolving capacity of the presented perfluorocarbons with other solvents like water and possibly gases like oxygen. PMID:27527753

  15. Distinguishing Signatures of Multipathway Conformational Transitions

    NASA Astrophysics Data System (ADS)

    Pierse, Christopher A.; Dudko, Olga K.

    2017-02-01

    The folding and binding of biomolecules into functional conformations are thought to be commonly mediated by multiple pathways rather than a unique route. Yet even in experiments where one can "see" individual conformational transitions, their stochastic nature generally precludes one from determining whether the transitions occurred through one or multiple pathways. We establish model-free, observable signatures in the response of macromolecules to force that unambiguously identify multiple pathways—even when the pathways themselves cannot be resolved. The unified analytical description reveals that, through multiple pathways, the response of molecules to external forces can be shaped in diverse ways, resulting in a rich design space for a tailored biological function already at the single-molecule level.

  16. Quantitative studies of ribosome conformational dynamics.

    PubMed

    Fraser, Christopher S; Doudna, Jennifer A

    2007-05-01

    The ribosome is a dynamic machine that undergoes many conformational rearrangements during the initiation of protein synthesis. Significant differences exist between the process of protein synthesis initiation in eubacteria and eukaryotes. In particular, the initiation of eukaryotic protein synthesis requires roughly an order of magnitude more initiation factors to promote efficient mRNA recruitment and ribosomal recognition of the start codon than are needed for eubacterial initiation. The mechanisms by which these initiation factors promote ribosome conformational changes during stages of initiation have been studied using cross-linking, footprinting, site-directed probing, cryo-electron microscopy, X-ray crystallography, fluorescence spectroscopy and single-molecule techniques. Here, we review how the results of these different approaches have begun to converge to yield a detailed molecular understanding of the dynamic motions that the eukaryotic ribosome cycles through during the initiation of protein synthesis.

  17. Conservation of the conformation of the porphyrin macrocycle in hemoproteins.

    PubMed Central

    Jentzen, W; Ma, J G; Shelnutt, J A

    1998-01-01

    The out-of-plane distortions of porphyrins in hemoproteins are characterized by displacements along the lowest-frequency out-of-plane normal coordinates of the D4h-symmetric macrocycle. X-ray crystal structures are analyzed using a computational procedure developed for determining these orthogonal displacements. The x-ray crystal structures of the heme groups are described within experimental error, using the set composed of only the lowest frequency normal coordinate of each out-of-plane symmetry type. That is, the distortion is accurately simulated by a linear combination of these orthonormal deformations, which include saddling (B2u), ruffling (B1u), doming (A2u), waving (Eg), and propellering (A1u). For example, orthonormal structural decomposition of the hemes in deoxymyoglobins reveals a predominantly dom heme deformation combined with a smaller wav(y) deformation. Generally, the heme conformation is remarkably similar for proteins from different species. For cytochromes c, the conformation is conserved as long as the amino acids between the cysteine linkages to the heme are homologous. Differences occur if this short segment varies in the number or type of residues, suggesting that this small segment causes the nonplanar distortion. Some noncovalently linked hemes like those in the peroxidases also have highly conserved characteristic distortions. Conservation occurs even for some proteins with a large natural variation in the amino acid sequence. PMID:9533688

  18. Photoinduced conformational switch of enantiopure azobenzenes controlled by a sulfoxide.

    PubMed

    Carreño, M Carmen; García, Isabel; Núñez, Irene; Merino, Estíbaliz; Ribagorda, María; Pieraccini, Silvia; Spada, Gian Piero

    2007-06-06

    Two series of enantiopure azobenzenes with a p-tolylsulfoxide at the ortho or meta position with respect to the azo group, have been regioselectively synthesized. Both can act as enantiopure molecular switches showing different structural features owing to the presence of the stereogenic sulfur. The photoisomerization process, studied by UV-vis, circular dichroism (CD), NMR, and chiral HPLC evidenced a double role of the sulfoxide. A transfer of chirality from the sulfoxide to the azo system was observed by CD in both cis and trans-isomers of the meta sulfinyl derivatives 3, whereas this perturbation was evident for the ortho sulfinyl series 7 only in the cis isomer. The NMR study evidenced that the s-cis rigid conformation of the bisaromatic sulfoxide was fixing a different orientation of the overall system in each series both in the trans and cis isomers, by forcing a final U-shaped structure in cis-3 and an S-shaped structure in cis-7. Very different values of specific optical rotations were measured in both trans and cis isomers, also reflecting the existence of distinct chiral entities in the photostationary states. The easy and reversible changes occurring between different conformational states could find applications in the photocontrol of several molecular switches.

  19. Conformational Dynamics of DNA Repair by Escherichia coli Endonuclease III*

    PubMed Central

    Kuznetsov, Nikita A.; Kladova, Olga A.; Kuznetsova, Alexandra A.; Ishchenko, Alexander A.; Saparbaev, Murat K.; Zharkov, Dmitry O.; Fedorova, Olga S.

    2015-01-01

    Escherichia coli endonuclease III (Endo III or Nth) is a DNA glycosylase with a broad substrate specificity for oxidized or reduced pyrimidine bases. Endo III possesses two types of activities: N-glycosylase (hydrolysis of the N-glycosidic bond) and AP lyase (elimination of the 3′-phosphate of the AP-site). We report a pre-steady-state kinetic analysis of structural rearrangements of the DNA substrates and uncleavable ligands during their interaction with Endo III. Oligonucleotide duplexes containing 5,6-dihydrouracil, a natural abasic site, its tetrahydrofuran analog, and undamaged duplexes carried fluorescent DNA base analogs 2-aminopurine and 1,3-diaza-2-oxophenoxazine as environment-sensitive reporter groups. The results suggest that Endo III induces several fast sequential conformational changes in DNA during binding, lesion recognition, and adjustment to a catalytically competent conformation. A comparison of two fluorophores allowed us to distinguish between the events occurring in the damaged and undamaged DNA strand. Combining our data with the available structures of Endo III, we conclude that this glycosylase uses a multistep mechanism of damage recognition, which likely involves Gln41 and Leu81 as DNA lesion sensors. PMID:25869130

  20. DFT conformational studies of the HI-6 molecule

    NASA Astrophysics Data System (ADS)

    Silva, Gustavo R.; Borges, Itamar; Figueroa-Villar, Jose D.

    A systematic study of the oxime HI-6 [1-(2-hydroxyiminomethyl-1-pyridinium)-1-(4-carboxy-aminopyridinium)dimethyl ether] hydrochloride, which is one of the most promising antidotes against soman intoxication, was carried out using density functional theory with the B3LYP (Becke, Lee, Yang, and Parr) method and the 6-31+G*, 6-31+G*, and 6-31+G** basis sets. Rotational barriers, equilibrium geometries, and charge distributions were calculated in order to investigate the role of the side chain for the larger oximes used as antidotes in the treatment of neurotoxic organophosphate poisoning. Also reported is the comparison between HI-6 and pralidoxime (2-PAM), a smaller oxime previously studied in our research group. It is shown that conformation minima for the protonated E isomer do not depend on the size of the side chain; on the other hand, this effect has a pronounced influence on the protonated Z isomer. For the unprotonated isomers, other effects, such as electrostatic interactions and resonance, should be taken into account in their conformational analysis.

  1. Group Theatre.

    ERIC Educational Resources Information Center

    Clark, Brian

    The group interpretation approach to theatre production is defined as a method that will lead to production of plays that will appeal to "all the layers of the conscious and unconscious mind." In practice, it means that the group will develop and use resources of the theatre that orthodox companies too often ignore. The first two chapters of this…

  2. Fluorine Substitution in Neurotransmitters: Microwave Spectroscopy and Modelling of the Conformational Space and Non Bonding Interactions

    NASA Astrophysics Data System (ADS)

    Melandri, S.; Maris, A.; Merloni, A.

    2011-06-01

    Fluorine substitution in molecules is a common practice in bio-organic chemistry in order to modulate physicochemical properties and biological activity of molecules and an increasing number of drugs on the market contain fluorine, the presence of which is often of major importance to modify pharmacokinetics properties and molecular activity. The rationale for such a strategy is that fluorine is generally a stronger electron acceptor than the other halogen atoms and its size is intermediate between that of hydrogen and oxygen. We have studied two fluorinated analogs of 2-phenylethylamine (PEA), the prototype molecule for adrenergic neurotransmitters, namely: 4-Fluoro (4FPEA) and 2-Fluoro-2-phenylethylamine (2FPEA) by Molecular Beam Fourier Transform Microwave Spectroscopy in the frequency range 6-18 GHz and ab initio calculations at the MP2/6311++G** level. The aim is to obtain information on the spatial arrangement of the ethylamine side chain and the effects of fluorination on the energy landscape. The conformational space is dominated by low energy gauche conformations stabilized by weak interactions between the aminic hydrogens and the electron cloud of the benzene ring and anti conformations higher in energy. In 2FPEA the presence of the fluorine atom almost duplicate the number of possible conformation with respect to 4FPEA. We observed two conformers of 4FPEA and five conformers of 2FPEA which have been classified with the guide provided by accurate ab initio calculations. The identification of the conformational species was helped by the analysis of the quadrupole hyperfine pattern which is greatly influenced by the orientation of the amino group and acts as a fingerprint for each conformation. The orientation of the dipole moment within the principal axis frame and the order of stability of the different conformations are other independent pieces of evidence for the unambiguous assignment and identification of the conformers. The order of stability was

  3. Changing chromatin fiber conformation by nucleosome repositioning.

    PubMed

    Müller, Oliver; Kepper, Nick; Schöpflin, Robert; Ettig, Ramona; Rippe, Karsten; Wedemann, Gero

    2014-11-04

    Chromatin conformation is dynamic and heterogeneous with respect to nucleosome positions, which can be changed by chromatin remodeling complexes in the cell. These molecular machines hydrolyze ATP to translocate or evict nucleosomes, and establish loci with regularly and more irregularly spaced nucleosomes as well as nucleosome-depleted regions. The impact of nucleosome repositioning on the three-dimensional chromatin structure is only poorly understood. Here, we address this issue by using a coarse-grained computer model of arrays of 101 nucleosomes considering several chromatin fiber models with and without linker histones, respectively. We investigated the folding of the chain in dependence of the position of the central nucleosome by changing the length of the adjacent linker DNA in basepair steps. We found in our simulations that these translocations had a strong effect on the shape and properties of chromatin fibers: i), Fiber curvature and flexibility at the center were largely increased and long-range contacts between distant nucleosomes on the chain were promoted. ii), The highest destabilization of the fiber conformation occurred for a nucleosome shifted by two basepairs from regular spacing, whereas effects of linker DNA changes of ?10 bp in phase with the helical twist of DNA were minimal. iii), A fiber conformation can stabilize a regular spacing of nucleosomes inasmuch as favorable stacking interactions between nucleosomes are facilitated. This can oppose nucleosome translocations and increase the energetic costs for chromatin remodeling. Our computational modeling framework makes it possible to describe the conformational heterogeneity of chromatin in terms of nucleosome positions, and thus advances theoretical models toward a better understanding of how genome compaction and access are regulated within the cell.

  4. Protein conformational studies for macromolecularly imprinted polymers.

    PubMed

    Kryscio, David R; Fleming, Michael Q; Peppas, Nicholas A

    2012-08-01

    CD is used to clearly show the negative impact of common ligands on the overall conformation of BSA, a typical protein template in macromolecularly imprinted polymers. This change occurs at concentrations far lower than those generally used in the literature. These findings are important as they offer insight into a potential fundamental reason for the lack of success in protein imprinting to date despite significant interest from the scientific community.

  5. Twist-boat conformation in graphene oxides.

    PubMed

    Samarakoon, Duminda K; Wang, Xiao-Qian

    2011-01-01

    We have investigated the structural, electronic, and vibrational properties of graphene oxide based on first-principles density-functional calculations. A twist-boat conformation is identified as the energetically most favorable nonmetallic configuration for fully oxidized graphene. The calculated Raman G-band blue shift is in very good agreement with experimental observations. Our results provide important insight into structural and electronic characteristics that are useful for further development of graphene-based nanodevices.

  6. Wideband embedded/conformal antenna subsystem concept

    NASA Astrophysics Data System (ADS)

    Smalanskas, Joseph P.; Valentine, Gary W.; Wolfson, Ronald I.

    1991-10-01

    The concept for a wideband, embedded/conformal antenna subsystem is presented. A multilayer radome not only protects the antenna from hostile environments, but also is designed to sustain aircraft dynamic loading. The radiating element consists of a planar, dual- flared slot capable of high-performance, multioctave operation. Advanced materials are currently being developed to enhance the low profile and efficient, wideband performance of the radiating element.

  7. Changing Chromatin Fiber Conformation by Nucleosome Repositioning

    PubMed Central

    Müller, Oliver; Kepper, Nick; Schöpflin, Robert; Ettig, Ramona; Rippe, Karsten; Wedemann, Gero

    2014-01-01

    Chromatin conformation is dynamic and heterogeneous with respect to nucleosome positions, which can be changed by chromatin remodeling complexes in the cell. These molecular machines hydrolyze ATP to translocate or evict nucleosomes, and establish loci with regularly and more irregularly spaced nucleosomes as well as nucleosome-depleted regions. The impact of nucleosome repositioning on the three-dimensional chromatin structure is only poorly understood. Here, we address this issue by using a coarse-grained computer model of arrays of 101 nucleosomes considering several chromatin fiber models with and without linker histones, respectively. We investigated the folding of the chain in dependence of the position of the central nucleosome by changing the length of the adjacent linker DNA in basepair steps. We found in our simulations that these translocations had a strong effect on the shape and properties of chromatin fibers: i), Fiber curvature and flexibility at the center were largely increased and long-range contacts between distant nucleosomes on the chain were promoted. ii), The highest destabilization of the fiber conformation occurred for a nucleosome shifted by two basepairs from regular spacing, whereas effects of linker DNA changes of ∼10 bp in phase with the helical twist of DNA were minimal. iii), A fiber conformation can stabilize a regular spacing of nucleosomes inasmuch as favorable stacking interactions between nucleosomes are facilitated. This can oppose nucleosome translocations and increase the energetic costs for chromatin remodeling. Our computational modeling framework makes it possible to describe the conformational heterogeneity of chromatin in terms of nucleosome positions, and thus advances theoretical models toward a better understanding of how genome compaction and access are regulated within the cell. PMID:25418099

  8. Protein Conformational Switches: From Nature to Design

    PubMed Central

    Ha, Jeung-Hoi

    2012-01-01

    Protein conformational switches alter their shape upon receiving an input signal, such as ligand binding, chemical modification, or change in environment. The apparent simplicity of this transformation—which can be carried out by a molecule as small as a thousand atoms or so—belies its critical importance to the life of the cell as well as its capacity for engineering by humans. In the realm of molecular switches, proteins are unique because they are capable of performing a variety of biological functions. Switchable proteins are therefore of high interest to the fields of biology, bio-technology, and medicine. These molecules are beginning to be exploited as the core machinery behind a new generation of biosensors, functionally regulated enzymes, and “smart” biomaterials that react to their surroundings. As inspirations for these designs, researchers continue to analyze existing examples of allosteric proteins. Recent years have also witnessed the development of new methodologies for introducing conformational change into proteins that previously had none. Herein we review examples of both natural and engineered protein switches in the context of four basic modes of conformational change: rigid-body domain movement, limited structural rearrangement, global fold switching, and folding–unfolding. Our purpose is to highlight examples that can potentially serve as platforms for the design of custom switches. Accordingly, we focus on inducible conformational changes that are substantial enough to produce a functional response (e.g., in a second protein to which it is fused), yet are relatively simple, structurally well-characterized, and amenable to protein engineering efforts. PMID:22688954

  9. Conformally flat solution with heat flux

    SciTech Connect

    Banerjee, A.; Dutta Choudhury, S. B.; Bhui, B. K.

    1989-07-15

    It is shown that the spherically symmetric solution previously given by Maiti is not the most general conformally flat solution for a shear-free and rotation-free fluid with heat flux. We have presented a more general solution for such a distribution and have considered the conditions of fit at the boundary of a simple spherically symmetric model with heat flux across the boundary with the exterior Vaidya metric.

  10. Sealing apparatus utilizing a conformable member

    DOEpatents

    Neef, William S.; Lambert, Donald R.

    1988-01-01

    Sealing apparatus and method, comprising first and second surfaces or membranes, at least one of which surfaces is deformable, placed in proximity to one another. Urging means cause these surfaces to contact one another in a manner such that the deformable surface "deforms" to conform to the geometry of the other surface, thereby creating a seal. The seal is capable of undergoing multiple cycles of sealing and unsealing.

  11. The Neuropeptide Oxytocin Enhances Information Sharing and Group Decision Making Quality.

    PubMed

    De Wilde, Tim R W; Ten Velden, Femke S; De Dreu, Carsten K W

    2017-01-11

    Groups can make better decisions than individuals when members cooperatively exchange and integrate their uniquely held information and insights. However, under conformity pressures group members are biased towards exchanging commonly known information, and away from exchanging unique information, thus undermining group decision-making quality. At the neurobiological level, conformity associates with the neuropeptide oxytocin. A double-blind placebo controlled study found no evidence for oxytocin induced conformity. Compared to placebo groups, three-person groups whose members received intranasal oxytocin, focused more on unique information (i) and repeated this information more often (ii). These findings reveal oxytocin as a neurobiological driver of group decision-making processes.

  12. The Neuropeptide Oxytocin Enhances Information Sharing and Group Decision Making Quality

    PubMed Central

    De Wilde, Tim R. W.; Ten Velden, Femke S.; De Dreu, Carsten K. W.

    2017-01-01

    Groups can make better decisions than individuals when members cooperatively exchange and integrate their uniquely held information and insights. However, under conformity pressures group members are biased towards exchanging commonly known information, and away from exchanging unique information, thus undermining group decision-making quality. At the neurobiological level, conformity associates with the neuropeptide oxytocin. A double-blind placebo controlled study found no evidence for oxytocin induced conformity. Compared to placebo groups, three-person groups whose members received intranasal oxytocin, focused more on unique information (i) and repeated this information more often (ii). These findings reveal oxytocin as a neurobiological driver of group decision-making processes. PMID:28074896

  13. A DFT and structural investigation of the conformations of Fischer carbene complexes

    NASA Astrophysics Data System (ADS)

    Landman, Marilé

    2015-09-01

    A set of different Fischer carbene complexes of group VI and VII metals, with varied heteroatom and heteroaromatic substituents on the carbene carbon atom, was studied. Density functional theory as well as single crystal diffraction techniques were employed to investigated the most stable conformation of these complexes. The complexes studied, [M(CO)4L{C(X)Z}], with L = PPh3 or CO, X = ethoxy (-OCH2CH3) or amino (-NH2 or NHCy) substituents as the heteroatom carbene substituents, Z = 2-furyl (-C4H3O), 2-thienyl (-C4H3S), 2-(N-methyl)pyrrolyl (-C4H3NCH3) as the second carbene substituent had their substituents varied systematically to give all the possible conformations of these complexes. The conformations of the complexes, in particular the relative orientations of the heteroatoms in the molecule (syn vs. anti), E/Z isomerism in the aminocarbene complexes and cis/trans isomerism in the ligand substituted complexes as well as various combinations of these aspects, were studied. In general, it was found that the most stable conformation theoretically as well as in the solid state for most of the complexes preferred the syn conformation. The Z-isomer is generally preferred over the E isomer while the cis is more predominant than the trans isomer. Using DFT and NBO calculations, explanations for the preferred conformations were explored. It was concluded that both steric and electronic factors influence the conformations of the carbene complexes, with the extent of contribution of these two factors varying for each of the different carbene substituents.

  14. Conformational preferences and synthesis of isomers Z and E of oxazole-dehydrophenylalanine.

    PubMed

    Staś, Monika; Bujak, Maciej; Broda, Małgorzata A; Siodłak, Dawid

    2016-05-01

    Dehydrophenylalanine, ΔPhe, is the most commonly studied α,β-dehydroamino acid. In nature, further modifications of the α,β-dehydroamino acids were found, for example, replacement of the C-terminal amide group by oxazole ring. The conformational properties of oxazole-dehydrophenylalanine residue (ΔPhe-Ozl), both isomers Z and E, were investigated. To determine all possible conformations, theoretical calculations were performed using Ac-(Z/E)-ΔPhe-Ozl(4-Me) model compounds at M06-2X/6-31++G(d,p) level of theory. Ac-(Z/E)-ΔPhe-Ozl-4-COOEt compounds were synthesized and the conformational preferences of each isomer, Z and E, were investigated using FTIR and NMR-NOE in solutions of increasing polarity (CHCl3 , DMSO-d6). The solid-state low-temperature structures of Ac-(Z)-ΔPhe-Ozl-4-COOEt and its intermediate analog Ac-(Z)-ΔPhe-Ozn(4-OH)-4-COOEt were also determined. In a weakly polar environment, the ΔPhe-Ozl residue has a tendency to adopt the conformation β2 with the calculated φ and ψ angles of -127° and 0° for the isomer Z and -170° and 26° for the isomer E. The increase of environment polarity favors the helical conformation α and the beta-turn like conformation β, but the conformation β2 seems to be still accessible. The (E)-ΔPhe-Ozl residue can be obtained from the isomer Z in photoisomerization reaction. However, hydroxyl-oxazoline-dehydrophenylalanine ΔPhe-Ozn(4-OH) decomposes in such conditions. Alternatively, (E)-ΔPhe-NH2 can be applied as a substrate in the Hantzsch reaction. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 283-294, 2016.

  15. Entropy reduction in unfolded peptides (and proteins) due to conformational preferences of amino acid residues.

    PubMed

    Schweitzer-Stenner, Reinhard; Toal, Siobhan E

    2014-11-07

    As established by several groups over the last 20 years, amino acid residues in unfolded peptides and proteins do not exhibit the unspecific random distribution as assumed by the classical random coil model. Individual amino acid residues in small peptides were found to exhibit different conformational preferences. Here, we utilize recently obtained conformational distributions of guest amino acid residues in GxG peptides to estimate their conformational entropy, which we find to be significantly lower than the entropy of an assumed random coil like distribution. Only at high temperature do backbone entropies approach random coil like values. We utilized the obtained backbone entropies of the investigated amino acid residues to estimate the loss of conformational entropy caused by a coil → helix transition and identified two subsets of amino acid residues for which the thus calculated entropy losses correlate well with the respective Gibbs energy of helix formation obtained for alanine based host-guest systems. Calculated and experimentally derived entropic losses were found to be in good agreement. For most of the amino acid residues investigated entropic losses derived from our GxG distributions correlate very well with corresponding values recently obtained from MD simulations biased by conformational propensities derived from truncated coil libraries. Both, conformational entropy and the entropy of solvation exhibit a strong, residue specific temperature dependence, which can be expected to substantially affect the stability of unfolded states. Altogether, our results provide strong evidence for the notion that conformational preferences of amino acid residues matter with regard to the thermodynamics of peptide and protein folding.

  16. Conformal invariance and new exact solutions of the elastostatics equations

    NASA Astrophysics Data System (ADS)

    Chirkunov, Yu. A.

    2017-03-01

    We fulfilled a group foliation of the system of n-dimensional (n ≥ 2) Lame equations of the classical static theory of elasticity with respect to the infinite subgroup contained in normal subgroup of main group of this system. It permitted us to move from the Lame equations to the equivalent unification of two first-order systems: automorphic and resolving. We obtained a general solution of the automorphic system. This solution is an n-dimensional analogue of the Kolosov-Muskhelishvili formula. We found the main Lie group of transformations of the resolving system of this group foliation. It turned out that in the two-dimensional and three-dimensional cases, which have a physical meaning, this system is conformally invariant, while the Lame equations admit only a group of similarities of the Euclidean space. This is a big success, since in the method of group foliation, resolving equations usually inherit Lie symmetries subgroup of the full symmetry group that was not used for the foliation. In the three-dimensional case for the solutions of the resolving system, we found the general form of the transformations similar to the Kelvin transformation. These transformations are the consequence of the conformal invariance of the resolving system. In the three-dimensional case with a help of the complex dependent and independent variables, the resolving system is written as a simple complex system. This allowed us to find non-trivial exact solutions of the Lame equations, which direct for the Lame equations practically impossible to obtain. For this complex system, all the essentially distinct invariant solutions of the maximal rank we have found in explicit form, or we reduced the finding of those solutions to the solving of the classical one-dimensional equations of the mathematical physics: the heat equation, the telegraph equation, the Tricomi equation, the generalized Darboux equation, and other equations. For the resolving system, we obtained double wave of a

  17. Causality constraints in conformal field theory

    DOE PAGES

    Hartman, Thomas; Jain, Sachin; Kundu, Sandipan

    2016-05-17

    Causality places nontrivial constraints on QFT in Lorentzian signature, for example fixing the signs of certain terms in the low energy Lagrangian. In d dimensional conformal field theory, we show how such constraints are encoded in crossing symmetry of Euclidean correlators, and derive analogous constraints directly from the conformal bootstrap (analytically). The bootstrap setup is a Lorentzian four-point function corresponding to propagation through a shockwave. Crossing symmetry fixes the signs of certain log terms that appear in the conformal block expansion, which constrains the interactions of low-lying operators. As an application, we use the bootstrap to rederive the well knownmore » sign constraint on the (Φ)4 coupling in effective field theory, from a dual CFT. We also find constraints on theories with higher spin conserved currents. As a result, our analysis is restricted to scalar correlators, but we argue that similar methods should also impose nontrivial constraints on the interactions of spinning operators« less

  18. Brain surface conformal parameterization with algebraic functions.

    PubMed

    Wang, Yalin; Gu, Xianfeng; Chan, Tony F; Thompson, Paul M; Yau, Shing-Tung

    2006-01-01

    In medical imaging, parameterized 3D surface models are of great interest for anatomical modeling and visualization, statistical comparisons of anatomy, and surface-based registration and signal processing. Here we introduce a parameterization method based on algebraic functions. By solving the Yamabe equation with the Ricci flow method, we can conformally map a brain surface to a multi-hole disk. The resulting parameterizations do not have any singularities and are intrinsic and stable. To illustrate the technique, we computed parameterizations of several types of anatomical surfaces in MRI scans of the brain, including the hippocampi and the cerebral cortices with various landmark curves labeled. For the cerebral cortical surfaces, we show the parameterization results are consistent with selected landmark curves and can be matched to each other using constrained harmonic maps. Unlike previous planar conformal parameterization methods, our algorithm does not introduce any singularity points. It also offers a method to explicitly match landmark curves between anatomical surfaces such as the cortex, and to compute conformal invariants for statistical comparisons of anatomy.

  19. Scattering and radiation from cylindrically conformal antennas

    NASA Astrophysics Data System (ADS)

    Kempel, Leo Charles

    Microstrip patch antennas offer considerable advantages in terms of weight, aerodynamic drag, cost, flexibility, and observability over more conventional protruding antennas. Two hybrid finite element methods are presented and are used to examine the scattering and radiation behavior of cylindrically conformal patches. In conjunction with a new divergence-free cylindrical shell element, the finite element-boundary integral method is shown to have low computational and memory requirements when compared with competing approaches. This method uses an efficient creeping wave series for the computation of the dyadic Green's function and a uniform surface mesh so that a fast Fourier transform may be used to reduce the computational and memory burden of the method. An alternative finite element-absorbing boundary condition approach incorporates a new conformal vector condition which minimizes the computational domain. The latter method is more flexible than the former because it can incorporate surface coatings and protruding antennas. Guidelines are established for minimal ABC displacement from the aperture. These two hybrid finite element methods are used to study the scattering, radiation, and input impedance of typical conformal antenna arrays. In particular, the effect of curvature and cavity size is examined for both discrete and wraparound antenna arrays.

  20. THz characterization of lysozyme at different conformations

    NASA Astrophysics Data System (ADS)

    Globus, Tatiana; Khromova, Tatyana; Lobo, Rebecca; Woolard, Dwight; Swami, Nathan; Fernandez, Erik

    2005-05-01

    This work demonstrates application of Fourier Transform Infrared Spectroscopy (FTIR) technique in the low terahertz frequency range of 10-25 cm-1 to discriminate between different protein conformations and evaluate possible application of THz spectroscopy for monitoring of protein folding-unfolding process. A specific procedure developed earlier for unfolding lysozyme by salt (KSCN) precipitation and refolding the lysozyme molecules by removing of KSCN and dissolving in sodium acetate was used to prepare three different forms of lysozyme. In addition, two standard procedures were used to prepare samples in unfolded conformation: denaturation at high temperature ~95° C followed by fast freezing, and dissolution in 6 M guanidine. Thin, air dried protein films were characterized as well as material in the form of gel. Spectra reveal resonance features in transmission which represent vibrational modes in the protein samples. A great variability of spectral features for the different conformational states showed the sensitivity of vibrational frequencies to the three dimensional structure of proteins. The results obtained on liquid (gel) samples indicate that THz transmission spectroscopy can be used for monitoring folding-unfolding process in a realistic, aqueous environment.