Results 11 to 20 of about 174,885 (266)
A generalization of the notion of helix
Turkish Journal of Mathematics, 2023 In this paper we generalize the notion of helix in the three-dimensional Euclidean space, which we define as that curve $\alpha$ for which there is an $F$-constant vector field $W$ along $\alpha$ that forms a constant angle with a fixed direction $V$ (called an axis of the helix).
Lucas, Pascual +1 more
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Driven toroidal helix as a generalization of the Kapitza pendulum
Physical Review E, 2022 We explore a model system consisting of a particle confined to move along a toroidal helix while being exposed to a static potential as well as a driving force due to a harmonically oscillating electric field. It is shown that in the limit of a vanishing helix radius the governing equations of motion coincide with those of the well-known Kapitza ...
J. F. Gloy, A. Siemens, P. Schmelcher
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Generalizing the Aromatic δ‐Amino Acid Foldamer Helix
Chemistry – A European Journal, 2022 AbstractA series of aromatic oligoamide foldamer sequences containing different proportions of three δ‐amino acids derived from quinoline, pyridine, and benzene and possessing varying flexibility, for example due to methylene bridges, were synthesized.
Daniel Bindl +2 more
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Tensioning the helix: a mechanism for force generation in twining plants [PDF]
Proceedings of the Royal Society B: Biological Sciences, 2009 Twining plants use their helical stems to clasp supports and to generate a squeezing force, providing stability against gravity. To elucidate the mechanism that allows force generation, we measured the squeezing forces exerted by the twinerDioscorea bulbiferawhile following its growth using time-lapse photography.
Isnard, Sandrine +4 more
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On the generation of Helix aspersa [PDF]
Annals and Magazine of Natural History, 1871 n ...
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CHARACTERIZATION OF THE SLANT HELIX AS SUCCESSOR CURVE OF THE GENERAL HELIX
International Electronic Journal of Geometry, 2014 In classical curve theory, the geometry of a curve in three dimen- sions is essentially characterized by their invariants, curvature and torsion. When they are given, the problem of nding a corresponding curve is known as 'solving natural equations'. Explicit solutions are known only for a handful of curve classes, including notably the plane curves ...
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The auto-inhibitory role of the EPAC hinge helix as mapped by NMR. [PDF]
PLoS ONE, 2012 The cyclic-AMP binding domain (CBD) is the central regulatory unit of exchange proteins activated by cAMP (EPAC). The CBD maintains EPAC in a state of auto-inhibition in the absence of the allosteric effector, cAMP.
Rajeevan Selvaratnam +3 more
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Structural basis of antifreeze activity of a bacterial multi-domain antifreeze protein. [PDF]
PLoS ONE, 2017 Antifreeze proteins (AFPs) enhance the survival of organisms inhabiting cold environments by affecting the formation and/or structure of ice. We report the crystal structure of the first multi-domain AFP that has been characterized.
Chen Wang +4 more
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Some new types of associated curves in Euclidean 3-space
Analele Stiintifice ale Universitatii Ovidius Constanta: Seria Matematica, 2018 In this paper, we introduce the concept of D-direction curve and C- direction curve of a given curve using the alternative frame –N,C,W} in Euclidean 3-space.
Özdoğan Sibel +3 more
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An Extended Winged Helix Domain in General Transcription Factor E/IIEα [PDF]
Journal of Biological Chemistry, 2003 Initiation of eukaryotic mRNA transcription requires melting of promoter DNA with the help of the general transcription factors TFIIE and TFIIH. Here we define a conserved and functionally essential N-terminal domain in TFE, the archaeal homolog of the large TFIIE subunit alpha.
Meinhart, Anton +2 more
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