1. Lecture 34 Chapter 3 Book 2
Please turn in term papers by to Kimberly Newman at
I would like to be able to share some of them with other in the class and to be able to follow up on some of the references. Thanks Frank

2. RF Exposures
1. The approach is from the point of view of Are exposure to radio frequency EMF a health hazard?
2. How do you go about finding out a given set of exposures is safe or not ?
3. If there are risks what are they?
4. The public and manufactures want to be able to say things are perfectly safe.
5. Result is a lot of measurement on RF field distributions and biological effects of them.

3. Issues
1. A problems in determining what the exposure is at the site of interest.
2. Changes with position of the body, size, shape, age. exposure source ( near field, far field etc.).
3. Problem in scaling from animal experiments to humans.
4. Changes in frequency, modulation, exposure time, peak vs. average power , repetition rates etc.
5. What are the important RF parameters from the point of view of the biology?

4. Issues 6. You have a lot of results that show no effects.
7. Many of those that do show effects are not reproduced by repeated experiments.
8. You need standards if you are going to manufacture things like cell phones and you need to have standards that say where and how powerful your transmitters are both in the phone and on the cell towers.

5. Issues 1. So how do you go about setting the standards.
2. How do you define what is safe or what levels of risk are you willing to take.
3. There is a lot of money at stake.
4. The result is a lot of measurements and experiments.

6. Issues
1. You have public pressure and people who say RF exposures are causing problems or are giving them problems.
2. Many of the experiments are from the question of is there a hazard. Thus the experiments are done higher levels of complexity. ( epidemiology on large populations, whole animal, organs , cells etc. )

7. Issues
3. At the high complexity levels you do not find what the physics is or do you separate out what the feedback and repair processes are.
4. From the risk prospective you may not care.
5. However, overall you need to know how the system works all the way from the physics through the chemistry and biology to health effects.
6. Additionally the effects are time dependent, and a function of the history, and the state of the person.

8. What do we know about RF 1. You get heating. SAR =σE2/ρ
2. ΔT varies with surface/volume and SAR
3. σ varies with material (water content)
4. The rate of change of temperature makes a difference.
5. Absorption mostly rather large line widths.
6. Specific protein absorptions are likely masked by the water absorption.

9. Heating
1. Heating and raising the temperature is the most obvious effect.
2. Define heating effects as important when ΔT>1oC This may not be adequate.
3. However, it is often use as a dividing line and there are exposures that lead to biological changes at power densities less than those causing ΔT>1oC
4. There are also many experiments at level below those that are too small to show significant heating of ΔT>1oC and show no changes with respect to the controls.

10. What do we know about RF
5. There are nonlinear and time dependent responses .
6. Modulated signals may lead to different results than CW.
7. Heating can be a demodulating mechanism.
8. Very careful measurements did not show nonlinearities at low power levels.

11. What do we know about RF
9. Direct Electric field effects on ions. Rapid oscillations lead to little net displacement and heating.
10. The gradients of the fields and forces on dipoles are likely to be more important.
11. Possible changes in molecular configuration. However, expect high fields to be required.

12. What do we know about RF 12 Most biological materials have µ≈µo
13. Exceptions are Fe, Mn, etc. that have net spins and magnetic moments.
14. We have radicals that have unpaired and magnetic moments.
15. These can be effected by magnetic fields and there are hyperfine transitions that fall in the RF region.
16 The RF magnetic fields can change radical concentrations with down stream biological effects.

13. Some Selected Data.
3.2 Response to Local Radio Frequency Exposure
3.3 Biochemical Changes
3.4 Cellular and Molecular Biology
3.4.1 Chromosome and Genetic Effects
3.4.2 Kinetic or Functional Changes and Membrane Effects
3.5 Reproduction, Growth, and Development
3.5.1 Reproduction
3.5.2 Embryonic Development and Teratology
3.5.3 Postnatal Development and Behavior
3.6 Effects on the Nervous System
3.6.1 Electroencephalographic Changes
3.6.2 Calcium Efflux
3.6.3 Histopathology
3.6.4 Effects on the Blood–Brain Barrier
3.6.5 Combined Effect of Radio Frequency and Drugs, and Radio
Frequency Effects on Neurotransmitters
3.6.6 Neurophysiologic Effects In Vitro

14. Some Selected Data
3.7 Behavioral Effects
3.7.1 Experimental Behavioral Studies
3.7.2 Behavioral Thermoregulation
3.8 Neuroendocrine Effects
3.8.1 Mechanisms of Interaction
3.8.2 Hypothalamic–Hypophysial–Adrenal Response
3.8.3 Hypothalamic–Hypophysial–Thyroid Response
3.8.4 Melatonin Response

15. Some Selected Data
3.9 Cardiovascular Effects
3.10 Effects on Hematopoiesis and Hematology
3.11 Effects on the Immune Response
Lymphocyte Kinetics
Adaptation
Influence of Hyperthermia
3.12 Carcinogenesis
Long-Term Animal Studies
Radiation or Chemically Initiated and Transgenic
Animal Bioassays
Tumor Cell Injection Bioassays
Summary of Animal Cancer Bioassays
3.13 Other Specialized Organ Response
Auditory Response
Ocular Effects
Threshold for Opacity in Rabbits
Biochemical Changes
Thermal Aspect of Microwave Cataractogenesis
Pulse Wave Exposures
Cumulative Effect
Extrapolation to the Human
Hypersensitivity