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Molecular motors are natural (biological) or artificial molecular machines that are the essential agents of movement in living organisms. In general terms, a motor is a device that consumes energy in one form and converts it into motion or mechanical work ; for example, many protein -based molecular motors harness the chemical free energy ...
Helicity is a pseudo-scalar quantity: it changes sign under change from a right-handed to a left-handed frame of reference; it can be considered as a measure of the handedness (or chirality) of the flow. Helicity is one of the four known integral invariants of the Euler equations; the other three are energy, momentum and angular momentum.
In statistical mechanics, the Zimm–Bragg model is a helix-coil transition model that describes helix-coil transitions of macromolecules, usually polymer chains. Most models provide a reasonable approximation of the fractional helicity of a given polypeptide; the Zimm–Bragg model differs by incorporating the ease of propagation (self-replication) with respect to nucleation.
The helicity of a particle is positive (" right-handed") if the direction of its spin is the same as the direction of its motion and negative ("left-handed") if opposite. Helicity is conserved. [1] That is, the helicity commutes with the Hamiltonian, and thus, in the absence of external forces, is time-invariant. It is also rotationally ...
Synthetic molecular motors are molecular machines capable of continuous directional rotation under an energy input. [2] Although the term "molecular motor" has traditionally referred to a naturally occurring protein that induces motion (via protein dynamics), some groups also use the term when referring to non-biological, non-peptide synthetic motors.
Brownian motors are nanoscale or molecular machines that use chemical reactions to generate directed motion in space. [1] The theory behind Brownian motors relies on the phenomenon of Brownian motion, random motion of particles suspended in a fluid (a liquid or a gas) resulting from their collision with the fast-moving molecules in the fluid. [2]
A proposed branch of research is the integration of molecular motor proteins found in living cells into molecular motors implanted in artificial devices. Such a motor protein would be able to move a "cargo" within that device, via protein dynamics , similarly to how kinesin moves various molecules along tracks of microtubules inside cells.
We have two cases, one where irreps are described by an integral multiple of 1 / 2 called the helicity, and the other called the "continuous spin" representation. For the third case The only finite-dimensional unitary solution is the trivial representation called the vacuum.