Sodium NMR/MRI for anisotropic systems

2015 ◽  
Vol 29 (2) ◽  
pp. 144-152 ◽  
Author(s):  
U. Eliav ◽  
G. Navon
Keyword(s):  
Sodium Nmr ◽  
Anisotropic Systems

Forced Periodic and Quasi-Periodic Patterns in Anisotropic Systems

1996 ◽  
Vol 6 (2) ◽  
pp. 305-328 ◽  
Author(s):  
Atsushi Ogawa ◽  
Walter Zimmermann ◽  
Kyozi Kawasaki ◽  
Toshihiro Kawakatsu
Keyword(s):  
Periodic Patterns ◽  
Anisotropic Systems

Eckhaus instability and defect nucleation in two-dimensional anisotropic systems

1991 ◽  
Vol 43 (10) ◽  
pp. 5728-5731 ◽  
Author(s):  
Steffen Rasenat ◽  
Erez Braun ◽  
Victor Steinberg
Keyword(s):  
Two Dimensional ◽  
Anisotropic Systems ◽  
Defect Nucleation ◽  
Eckhaus Instability

scholarly journals Chirality Matters: Biological Activity of Optically Pure Silybin and Its Congeners

2021 ◽  
Vol 22 (15) ◽  
pp. 7885
Author(s):  
Vladimír Křen
Keyword(s):  
Neurological Diseases ◽  
Biological Effects ◽  
Drug Metabolizing Enzymes ◽  
Metabolizing Enzymes ◽  
Biological Targets ◽  
Molecular Effects ◽  
Anisotropic Systems ◽  
Specific Activities ◽  
Optically Pure

This review focuses on the specific biological effects of optically pure silymarin flavo-nolignans, mainly silybins A and B, isosilybins A and B, silychristins A and B, and their 2,3-dehydro derivatives. The chirality of these flavonolignans is also discussed in terms of their analysis, preparative separation and chemical reactions. We demonstrated the specific activities of the respective diastereomers of flavonolignans and also the enantiomers of their 2,3-dehydro derivatives in the 3D anisotropic systems typically represented by biological systems. In vivo, silymarin flavonolignans do not act as redox antioxidants, but they play a role as specific ligands of biological targets, according to the “lock-and-key” concept. Estrogenic, antidiabetic, anticancer, antiviral, and antiparasitic effects have been demonstrated in optically pure flavonolignans. Potential application of pure flavonolignans has also been shown in cardiovascular and neurological diseases. Inhibition of drug-metabolizing enzymes and modulation of multidrug resistance activity by these compounds are discussed in detail. The future of “silymarin applications” lies in the use of optically pure components that can be applied directly or used as valuable lead structures, and in the exploration of their true molecular effects.

scholarly journals Anisotropic nanocrystal shape and ligand design for co-assembly

2021 ◽  
Vol 7 (23) ◽  
pp. eabf9402
Author(s):  
Katherine C. Elbert ◽  
William Zygmunt ◽  
Thi Vo ◽  
Corbin M. Vara ◽  
Daniel J. Rosen ◽  
...  
Keyword(s):  
Rational Design ◽  
Ligand Design ◽  
Building Blocks ◽  
Two Dimensional ◽  
Secondary System ◽  
Assembly Design ◽  
Ligand Shell ◽  
Powerful Approach ◽  
Anisotropic Systems ◽  
Direct Materials

The use of nanocrystal (NC) building blocks to create metamaterials is a powerful approach to access emergent materials. Given the immense library of materials choices, progress in this area for anisotropic NCs is limited by the lack of co-assembly design principles. Here, we use a rational design approach to guide the co-assembly of two such anisotropic systems. We modulate the removal of geometrical incompatibilities between NCs by tuning the ligand shell, taking advantage of the lock-and-key motifs between emergent shapes of the ligand coating to subvert phase separation. Using a combination of theory, simulation, and experiments, we use our strategy to achieve co-assembly of a binary system of cubes and triangular plates and a secondary system involving two two-dimensional (2D) nanoplates. This theory-guided approach to NC assembly has the potential to direct materials choices for targeted binary co-assembly.

The Application of the Beer-Lambert Law to Optically Anisotropic Systems

Science ◽  
1949 ◽  
Vol 110 (2845) ◽  
pp. 41-43 ◽  
Author(s):  
B. Commoner ◽  
D. Lipkin
Keyword(s):  
Anisotropic Systems

scholarly journals Quantum critical scaling and holographic bound for transport coefficients near Lifshitz points

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Gian Andrea Inkof ◽  
Joachim M. C. Küppers ◽  
Julia M. Link ◽  
Blaise Goutéraux ◽  
Jörg Schmalian
Keyword(s):  
Field Theory ◽  
Transport Coefficients ◽  
Massless Scalar ◽  
Famous Conjecture ◽  
Strongly Coupled ◽  
Spatial Anisotropy ◽  
Anisotropic Scaling ◽  
Geometric Ratio ◽  
Anisotropic Systems ◽  
Gauge Gravity

Abstract The transport behavior of strongly anisotropic systems is significantly richer compared to isotropic ones. The most dramatic spatial anisotropy at a critical point occurs at a Lifshitz transition, found in systems with merging Dirac or Weyl point or near the superconductor-insulator quantum phase transition. Previous work found that in these systems a famous conjecture on the existence of a lower bound for the ratio of a shear viscosity to entropy is violated, and proposed a generalization of this bound for anisotropic systems near charge neutrality involving the electric conductivities. The present study uses scaling arguments and the gauge-gravity duality to confirm the previous analysis of universal bounds in anisotropic Dirac systems. We investigate the strongly-coupled phase of quantum Lifshitz systems in a gravitational Einstein-Maxwell-dilaton model with a linear massless scalar which breaks translations in the boundary dual field theory and sources the anisotropy. The holographic computation demonstrates that some elements of the viscosity tensor can be related to the ratio of the electric conductivities through a simple geometric ratio of elements of the bulk metric evaluated at the horizon, and thus obey a generalized bound, while others violate it. From the IR critical geometry, we express the charge diffusion constants in terms of the square butterfly velocities. The proportionality factor turns out to be direction-independent, linear in the inverse temperature, and related to the critical exponents which parametrize the anisotropic scaling of the dual field theory.

In–Out Intermittency with Nested Subspaces in a System of Globally Coupled, Complex Ginzburg–Landau Equations

2021 ◽  
Vol 31 (01) ◽  
pp. 2130001
Author(s):  
Gerhard Dangelmayr ◽  
Iuliana Oprea
Keyword(s):  
Normal Form ◽  
Traveling Waves ◽  
Complex Dynamics ◽  
Invariant Subspaces ◽  
Chaotic Attractors ◽  
Governing Equations ◽  
Ginzburg Landau ◽  
Higher Dimensional ◽  
Ginzburg Landau Equations ◽  
Anisotropic Systems

Chaos and intermittency are studied for the system of globally coupled, complex Ginzburg–Landau equations governing the dynamics of extended, two-dimensional anisotropic systems near an oscillatory (Hopf) instability of a basic state with two pairs of counterpropagating, oblique traveling waves. Parameters are chosen such that the underlying normal form, which governs the dynamics of the spatially constant modes, has two symmetry-conjugated chaotic attractors. Two main states residing in nested invariant subspaces are identified, a state referred to as Spatial Intermittency ([Formula: see text]) and a state referred to as Spatial Persistence ([Formula: see text]). The [Formula: see text]-state consists of laminar phases where the dynamics is close to a normal form attractor, without spatial variation, and switching phases with spatiotemporal bursts during which the system switches from one normal form attractor to the conjugated normal form attractor. The [Formula: see text]-state also consists of two symmetry-conjugated states, with complex spatiotemporal dynamics, that reside in higher dimensional invariant subspaces whose intersection forms the 8D space of the spatially constant modes. We characterize the repeated appearance of these states as (generalized) in–out intermittency. The statistics of the lengths of the laminar phases is studied using an appropriate Poincaré map. Since the Ginzburg–Landau system studied in this paper can be derived from the governing equations for electroconvection in nematic liquid crystals, the occurrence of in–out intermittency may be of interest in understanding spatiotemporally complex dynamics in nematic electroconvection.

Polarization-analyzed small-angle neutron scattering. II. Mathematical angular analysis

2012 ◽  
Vol 45 (3) ◽  
pp. 554-565 ◽  
Author(s):  
Kathryn Krycka ◽  
Julie Borchers ◽  
Yumi Ijiri ◽  
Ryan Booth ◽  
Sara Majetich
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Magnetic Moments ◽  
Magnetic Scattering ◽  
Directional Sensitivity ◽  
Angular Analysis ◽  
Structural Contribution ◽  
Anisotropic Systems ◽  
Simplified Procedures

Polarization-analyzed small-angle neutron scattering (SANS) is a powerful tool for the study of magnetic morphology with directional sensitivity. Building upon polarized scattering theory, this article presents simplified procedures for the reduction of longitudinally polarized SANS into terms of the three mutually orthogonal magnetic scattering contributions plus a structural contribution. Special emphasis is given to the treatment of anisotropic systems. The meaning and significance of scattering interferences between nuclear and magnetic scattering and between the scattering from magnetic moments projected onto distinct orthogonal axes are discussed in detail. Concise tables summarize the algorithms derived for the most commonly encountered conditions. These tables are designed to be used as a reference in the challenging task of extracting the full wealth of information available from polarization-analyzed SANS.

scholarly journals Structure and Stability of a Dimeric G-Quadruplex Formed by Cyclic Oligonucleotides

2010 ◽  
Vol 2010 ◽  
pp. 1-6 ◽  
Author(s):  
Joan Casals ◽  
Júlia Viladoms ◽  
Enrique Pedroso ◽  
Carlos González
Keyword(s):  
Telomeric Repeat ◽  
High Melting ◽  
Structure And Stability ◽  
Dimeric Structure ◽  
Nmr Data ◽  
High Melting Temperature ◽  
Sodium Nmr ◽  
G Quadruplex ◽  
Global Topology ◽  
Quadruplex Formation

We have studied the structure and stability of the cyclic dodecamer d<pGGGTTAGGGTTA>, containing two copies of the human telomeric repeat. In the presence of sodium, NMR data are consistent with a dimeric structure of the molecule in which two cycles self-associate forming a quadruplex with three guanine tetrads connected by edgewise loops. The two macrocycles are arranged in a parallel way, and the dimeric structure exhibits a high melting temperature. These results indicate that cyclization of the phosphodiester chain does not prevent quadruplex formation, although it affects the global topology of the quadruplex.

Sign in / Sign up

Export Citation Format

Share Document