Field sensitive

A SQUID [2] provides two basic advantages for measuring small variations in the magnetic field caused by cracks [3-7]. First, its unsurpassed field sensitivity is independent of frequency and thus dc and ac fields can be measured with an resolution of better than IpT/VHz. Secondly, the operation of the SQUID in a flux locked loop can provide a more than sufficient dynamic range of up to 160 dB/VHz in a shielded environment, and about 140 dB/>/Hz in unshielded environment [8]. 

Zrinyi, M., Szabo, D., and Feher, J., Comparative studies of electro- and magnetic field sensitive pol3mier gel. Proceedings ofSPIE 6th Annual International Symposium of Smart Structures and Materials, EAPAD Conf, 3669, pp. 406 13, 1999. 

Clarke R (2010) Electric field sensitive dyes. In Demchenko AP (ed) Advanced Fluorescence Reporters in Chemistry and Biology I. Springer Ser Fluoresc 8 331-344... 

Electric field sensitive dyes respond to changes in electrical membrane potential by a variety of different mechanisms with widely varying response times depending on their chemical structure and their interaction with the membrane. An understanding of the mechanisms of dye response and their response mechanisms is important for an appropriate choice of a probe for a particular application. The purpose of this chapter is, therefore, to provide an overview of the dyes presently available, how they respond to voltage changes, and give some examples of how they have been applied. Finally, because there is still scope for the development of new dyes with improved properties, some directions for future research will be discussed. 

Fig. 1 Examples of the structures of a few slow-response electric field sensitive dyes 3, 3 -dipropylthiadicarbocyanine (DiSC3(5)), tetramethylrhodamine methyl ester (TMRM), and bis-(3-propyl-5-oxoisooxazol-4-yl)pentamine oxonol (oxonol VI)...

Up to now in this chapter, we have concentrated on the measurement via electric field sensitive dyes of the transmembrane electrical potential, which by itself should produce a linear drop in the electrical potential across a membrane. However, at least through the lipid matrix of a cell membrane, the electrical potential, /, at any point does not change linearly across the membrane. Instead, it follows a complex profile (see Fig. 6). This is due to contributions other than the transmembrane electrical potential to /. The other contributions come from the surface potential and the dipole potential. Both of these can also be quantified via electric field sensitive dyes. 

The ideal electric field sensitive dye would respond to changes in intramembrane field strength or transmembrane electrical potential within femtoseconds the magnitude of its absorbance or fluorescence response would be enormous it would... 

I could feel and sense input from all manner of environmental elements and food and so forth. At the time I had no context for what was happening, and felt quite mad. Some of what I considered madness at the time was actually my having been acutely perceptive and acutely accurate about what I felt and sensed. Those of us with chemical and electromagnetic field sensitivities have extra senses. I have no way to accurately describe these to people who have never experienced it. It is a true advantage in many respects, but it s weird being that odd person who can sense trouble—that the power lines are leaking or the gas line is leaking. 

In Marin I ran into situations time and again when someone I knew couldn t enter the hospital because there was new carpet, or couldn t get a pap smear or a breast exam, or couldn t take kids to the ER or to a clinic because of chemical barriers. I began working with some of the disability activists in Marin County and San Francisco and tried to learn what the laws were. In 1985 I started a newsletter, called The Reactor, about civil rights and access rights for people with chemical and electric magnetic field sensitivities. 

Fears of homelessness lie dormant in most people, until health or resources are in jeopardy. Any catastrophic or chronic illness can bring those fears and the possibility of homelessness closer to the surface. People with MCS and electromagnetic fields sensitivity (EMFS) are particularly vulnerable. Christina Jacobs is one example, and a model for facing the reality of homelessness with hope and perseverance. She has lived out of her car for most of seven years. 

It has been proposed to base ion optrodes on the Stark effect that the electrostatic field at the membrane/solution interface creates in field-sensitive dyes (Wolfbeis and Schaffar, 1987). This effect relates the frequency shift Av of the permanent dipole, u of the dye to the local electric field, according to the equation... 

Stimuli-responsive homo- and copolymeric hydrogels with pH, temperature, ionic strength, solvation, electrical field, or magnetic field-sensitive pendent groups have been produced for drug, peptide and protein delivery devices, for biosensors and for tissue engineering. Their swelling behaviour, net-... 

The laboratory sensitivity of a species approximates its field sensitivity. 

Presdi, D. Pettigrew, J.D. Ferromagnetic coupling to muscle receptors as a basis for geomagnetic field sensitivity in animals. Nature 1980, 285, 99-101. 

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