Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

¹H NMR: Interpreting Distorted and Overlapping Signals01:02

¹H NMR: Interpreting Distorted and Overlapping Signals

1.5K
Spin systems where the difference in chemical shifts of the coupled nuclei is greater than ten times J are called first-order spin systems. These nuclei are weakly coupled, and their chemical shifts and coupling constant can generally be estimated from the well-separated signals in the spectrum.
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
1.5K
Atomic Nuclei: Nuclear Relaxation Processes01:23

Atomic Nuclei: Nuclear Relaxation Processes

1.2K
In the absence of an external magnetic field, nuclear spin states are degenerate and randomly oriented. When a magnetic field is applied, the spins begin to precess and orient themselves along (lower energy) or against (higher energy) the direction of the field. At equilibrium, a slight excess population of spins exists in the lower energy state. Because the direction of the magnetic field is fixed as the z-axis,  the precessing magnetic moments are randomly oriented around the z-axis.
1.2K
Valence Bond Theory02:42

Valence Bond Theory

11.2K
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
11.2K
Interpreting ¹H NMR Signal Splitting: The (n + 1) Rule01:10

Interpreting ¹H NMR Signal Splitting: The (n + 1) Rule

2.4K
In the AX proton spin system, proton A can sense the two spin states of a coupled proton X, resulting in a doublet NMR signal with two peaks of equal (1:1) intensity. When proton A is coupled to two equivalent protons (AX2 spin system), the spin states of each X can be aligned with or against the external field, creating three possible scenarios. This results in a 1:2:1  triplet signal, where the central peak corresponds to the chemical shift of A and is twice as large or intense as the...
2.4K
Atomic Nuclei: Nuclear Spin State Overview01:03

Atomic Nuclei: Nuclear Spin State Overview

1.9K
NMR-active nuclei have energy levels called 'spin states' that are associated with the orientations of their nuclear magnetic moments. In the absence of a magnetic field, the nuclear magnetic moments are randomly oriented, and the spin states are degenerate. When an external magnetic field is applied, the spin states have only 2 + 1 orientations available to them. A proton with = ½ has two available orientations. Similarly, for a quadrupolar nucleus with a nuclear spin value of one, the...
1.9K
π Electron Effects on Chemical Shift: Aromatic and Antiaromatic Compounds01:14

π Electron Effects on Chemical Shift: Aromatic and Antiaromatic Compounds

1.8K
In aromatic compounds, such as benzene, the circulation of (4n + 2) π-electrons sets up a diamagnetic or diatropic ring current around the perimeter of the molecule. This current induces a magnetic field that opposes the external field inside the ring and reinforces it on the outside. The protons in benzene are deshielded and exhibit high chemical shifts in the range 6.5–8.5 ppm. The shielding effect at the center of the ring is evident in complex aromatic molecules, such as...
1.8K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

A novel reaction-diffusion architecture for engineering self-organized patterns in mammalian cells.

bioRxiv : the preprint server for biology·2026
Same author

Actuation of Cell Layers in Three Dimensions.

Advanced materials (Deerfield Beach, Fla.)·2026
Same author

Collective epithelial migration mediated by the unbinding of hexatic defects.

eLife·2026
Same author

Topological defects lead to energy transfer in active nematics.

Nature communications·2026
Same author

Controlled propagation of soliton bullets in an engineered strain field.

Proceedings of the National Academy of Sciences of the United States of America·2026
Same author

Self-assembly pathways towards floppy colloidal square lattices.

Nature communications·2025
Same journal

A predisposing effect of HLA class II genes in celiac disease by skewing the naive CD4<sup>+</sup> T cell receptor repertoire.

Proceedings of the National Academy of Sciences of the United States of America·2026
Same journal

Wave propagation in fluid-saturated nanoporous media: Upscaling molecular mechanics into continuum-level description.

Proceedings of the National Academy of Sciences of the United States of America·2026
Same journal

Collagen-producing eye cell atlas reveals distinct fibroblast fates in early injury vs. fibrotic subretinal disease.

Proceedings of the National Academy of Sciences of the United States of America·2026
Same journal

Knotted solid tori in contact manifolds.

Proceedings of the National Academy of Sciences of the United States of America·2026
Same journal

Biophysical fitness landscape design traps viral evolution.

Proceedings of the National Academy of Sciences of the United States of America·2026
Same journal

Cryo-EM of the eukaryotic purine transporter UapA demonstrates intramolecular and lipid regulation of transport.

Proceedings of the National Academy of Sciences of the United States of America·2026
See all related articles

Related Experiment Video

Updated: Jan 16, 2026

Forming, Confining, and Observing Microtubule-Based Active Nematics
08:37

Forming, Confining, and Observing Microtubule-Based Active Nematics

Published on: January 13, 2023

3.1K

Hidden order in active nematic defects.

Alexis de la Cotte1,2, Daniel J G Pearce3, Jyothishraj Nambisan1,2

  • 1Department of Condensed Matter Physics, University of Barcelona, Barcelona 08028, Spain.

Proceedings of the National Academy of Sciences of the United States of America
|September 29, 2025
PubMed
Summary
This summary is machine-generated.

Active nematic defects show suppressed fluctuations, exhibiting hidden order across scales. This hyperuniformity arises from activity, not thermal effects, revealing organization in disordered systems.

Keywords:
active matterhyperuniformitynematic defectsnumber fluctuations

More Related Videos

Theoretical Calculation and Experimental Verification for Dislocation Reduction in Germanium Epitaxial Layers with Semicylindrical Voids on Silicon
06:57

Theoretical Calculation and Experimental Verification for Dislocation Reduction in Germanium Epitaxial Layers with Semicylindrical Voids on Silicon

Published on: July 17, 2020

2.6K
High-Contrast and Fast Photorheological Switching of a Twist-Bend Nematic Liquid Crystal
06:24

High-Contrast and Fast Photorheological Switching of a Twist-Bend Nematic Liquid Crystal

Published on: October 31, 2019

6.8K

Related Experiment Videos

Last Updated: Jan 16, 2026

Forming, Confining, and Observing Microtubule-Based Active Nematics
08:37

Forming, Confining, and Observing Microtubule-Based Active Nematics

Published on: January 13, 2023

3.1K
Theoretical Calculation and Experimental Verification for Dislocation Reduction in Germanium Epitaxial Layers with Semicylindrical Voids on Silicon
06:57

Theoretical Calculation and Experimental Verification for Dislocation Reduction in Germanium Epitaxial Layers with Semicylindrical Voids on Silicon

Published on: July 17, 2020

2.6K
High-Contrast and Fast Photorheological Switching of a Twist-Bend Nematic Liquid Crystal
06:24

High-Contrast and Fast Photorheological Switching of a Twist-Bend Nematic Liquid Crystal

Published on: October 31, 2019

6.8K

Area of Science:

  • Physics
  • Statistical Mechanics
  • Soft Matter Physics

Background:

  • Hyperuniformity and giant number fluctuations are key concepts in non-equilibrium systems.
  • Active matter is often characterized by large fluctuations, contrasting with hyperuniformity observed in ordered systems.

Purpose of the Study:

  • To investigate the statistical correlations in active nematic defects.
  • To determine if active nematic defects exhibit hyperuniformity or giant number fluctuations.
  • To elucidate the role of activity versus thermal fluctuations in defect organization.

Main Methods:

  • Modeling nematic defects using continuum densities.
  • Analyzing experimental findings.
  • Employing hydrodynamic theory and agent-based simulations.

Main Results:

  • Active nematic defects display suppressed fluctuations, akin to ordered lattices.
  • Hyperuniformity emerges in the limit of activity-driven proliferation, independent of thermal fluctuations.
  • A finite range of length scales characterizes hyperuniformity when both activity and thermal effects are present.
  • Subpopulations of positive or negative defects show enhanced organization, indicating a lack of multihyperuniformity.

Conclusions:

  • The disordered state of active nematic defects possesses hidden order across scales.
  • Activity-driven proliferation is crucial for achieving hyperuniformity in these systems.
  • The interplay between defect dynamics (creation/annihilation, repulsion/attraction) and external factors governs the emergent hyperuniform structure.