Gradient and Body Electric

gradient Gradient is a mathematical concept to measure the change of a scalar function over a specified distance and along a given direction. In physical applications, the scalar function can be chemical concentration (as shown in Figure 01), temperature, pressure, heat, gravitational potential, electrical potential, ... etc. The mathematical formula for change of the scalar function in a particular direction is just the slope of the curve:

where n indicates the direction of change.

Figure 01 Chemical Gradient [view large image]

In general the formula for change of a scalar function in any direction can be expressed as:


where i, j, and k are unit vectors along the x, y, and z axis respectively.

The gradient is positive if the scalar function increases toward the direction of change, and is negative for the reverse. Thus the bacteria in Figure 01 must have equiped with sensor that can discern the positive or negative of the chemical gradient.

The gradient of the gravitational or electrical potential is the field, which is equal to the force by multiplying an appropriate coupling conatant. A magnetic gradiometer detects the magnetic gradient; it can be used to locate object under the Earth's surface. While a gravity gradiometer measures gravitational gradient; it can be used as verification tool to check the load inside a container or the war head of a missile etc.

Body Electric The gradient of the electric potential defines the electric field: E = -dV/dr n. Biologists have known for more than 200 years that nerve impulses are transmitted electrically. Research on body electric has been revived only recently in the past two decades. Countless studies have since confirmed that externally applied electric fields can affect the behaviour of cultured cells, influencing the way they migrate, develop and grow. Internally generated electric fields (typically between 10 and 100 millivolts per millimetre) are an inevitable product of biological systems. Cell membranes and epithelia routinely pump ions from one side to the other, creating gradients in electrical potential. It is found that the electric fields play a vital role in wound healing and regeneration of body parts in lower animals (see Figure 02). It also

Figure 02 Body Electric[view large image]

provides a "spatial cues" to establish the left-right asymmetry in embryonic development.
Qigang Myelin Sheath The concept of acupuncture points and meridians in Qigong (see Figure 03) has been explored in China for two thousand years. The physical base has not been identified until some measurements were conducted in the 1970s. It indicates that there is current carried by the myelin sheath laid down by specialized cells called Schwann cells (see Figure 04). The cells that biologists had considered merely insulation turned out to be the real wires to conduct the DC current. It is thought that the acupuncture points along the meridians may act as amplifiers to maintain the strength of the current, similar to the booster amplifiers along a transmission line used to keep the signal from getting weaker with distance. Unfortunately, further study ceased abruptly when NIH canceled the research grant.

Figure 03 Qigong [view large image]

Figure 04 Myelin Sheath [view large image]