Thinking gradients

Peter Mitchell s chemiosmotic hypothesis revolutionized our thinking about the energy coupling that drives ATP synthesis by means of an electrochemical gradient. How much energy is stored in this electrochemical gradient For the transmembrane flow of protons across the inner membrane (from inside [matrix] to outside), we could write... 

Robert Richards I would think that to be a pseudo-account. Gradients don t do anything except lie on a page. 

Eugene Dowdle So now you know that I think that here, we might find a much tighter correlation with a gradient than social effects. You think it s possible ... 

The creation of nanoscale sandwiches of compound semiconductor heterostructures, with gradients of chemical composition that are precisely sculpted, could produce quantum wells with appropriate properties. One can eventually think of a combined device that incorporates logic, storage, and communication for computing—based on a combination of electronic, spintronic, photonic, and optical technologies. Precise production and integrated use of many different materials will be a hallmark of future advanced device technology. 

Now in convection we can obtain the velocity of the particle by multiplying the velocity gradient, i.e. shear rate, by the distance moved by the particle. We can think of this as some multiple of the particle radius, ... 

Certainly there are examples of the transport of neutral molecules against their chemical potential gradients. In specific cases (e.g., amino acids) this seems to occur as a consequence of coupling between the flow of the neutral molecule and that of an ion that is actively transported. However, I do not think any generalizations can be made. 

In terms of the gradient of the stationary-state locus, the condition expressed by eqn (7.55) locates a singular point as dx/drres - 0/0. Loosely, we can think of the locus simultaneously having turning points both horizontally and vertically, as indicated in Fig. 7.7. This corresponds to situations such as (a) an isolated point or (b) the transcritical touching of two branches. 

You might think that gradients are an endlessly beneficial technology, but in fact there are a few minor disadvantages of gradient coherence pathway selection ... 

We also have to think about the phase sensitive detection in both indirect dimensions. For example, if the phase is encoded in States mode in t and in echo-antiecho mode (using gradients) in t2, we have to acquire four FIDs for each combination of t and t2 delay values. States mode real or imaginary is selected by using an x or y phase for the pulse just before the t delay (lH SQC), and echo or antiecho mode is selected by using a negative gradient... 

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