Search results
Results from the WOW.Com Content Network
Fluorescence microscopy relies upon fluorescent compounds, or fluorophores, in order to image biological systems.Since fluorescence and phosphorescence are competitive methods of relaxation, a fluorophore that undergoes intersystem crossing to the triplet excited state no longer fluoresces and instead remains in the triplet excited state, which has a relatively long lifetime, before ...
Some level crossings that are located close to intersections with traffic lights program the signals with a preemption sequence so when the approaching train trips the track circuit, it not only activates the crossing signals, but also changes the traffic lights facing the crossing to green, to clear any traffic that may be queued on the ...
Level crossing signals are electronic warning devices for road vehicles at railroad level crossings. Level crossings can be operated in various ways. In some countries such as the UK, the warning devices are more often than not activated by remote control, I.e. an operator pressing buttons. However, the majority of countries have automated systems.
Typically, the signaling process involves three components: the signal, the receptor, and the effector. [citation needed] In biology, signals are mostly chemical in nature, but can also be physical cues such as pressure, voltage, temperature, or light. Chemical signals are molecules with the ability to bind and activate a specific receptor.
Second-harmonic generation can be produced by several non-centrosymmetric organic dyes; however, most of the organic dyes also generate collateral fluorescence along with second-harmonic generation signals. [32] Until now, only two classes of organic dyes have been shown which do not produce any collateral fluorescence and works purely on ...
A level crossing is an intersection where a railway line crosses a road, path, or (in rare situations) airport runway, at the same level, [1] as opposed to the railway line or the road etc. crossing over or under using an overpass or tunnel.
Each gap junction (sometimes called a nexus) contains numerous gap junction channels that cross the plasma membranes of both cells. [11] With a lumen diameter of about 1.2 to 2.0 nm, [2] [12] the pore of a gap junction channel is wide enough to allow ions and even medium-size molecules like signaling molecules to flow from one cell to the next, [2] [13] thereby connecting the two cells' cytoplasm.
Two-photon physics, also called gamma–gamma physics, is a branch of particle physics that describes the interactions between two photons. Normally, beams of light pass through each other unperturbed. Inside an optical material, and if the intensity of the beams is high enough, the beams may affect each other through a variety of non-linear ...