CSIRO - June 1994




In radio wave propagation, attenuation of a radio wave due to its energy being dissipated, i.e., converted into another form, such as heat.
Encompassing or surrounding area.
Antenna regions
The distinction between electromagnetic fields far from, and those near to, the antenna. The regions are usually classified into three zones; near (static) zone, intermediate (induction) zone and far zone, located by drawing spheres of different radii around the antenna. The radii are approximately r < l for the near zone, r _ l for the intermediate zone, and r > l for the far zone. Note that l is the wavelength of the electromagnetic field produced by the antenna. In the far zone, field components (E and H) lie transverse to the direction of the propagation, and the shape of the field pattern is independent of the radius at which it is taken. In the near and intermediate zones, the field patterns are quite complicated, and the shape is, in general, a function of the radius and angular position (azimuth and elevation) in front of the antenna.
The part of a radio system that is designed to radiate electromagnetic waves into free space (or to receive them). This does not include the transmission lines or waveguide to the radiator.
Something the immune system recognises as foreign. An antigenic determinant is the small part, of a larger foreign target, which is actually recognised.
Athermal effect (nonthermal effect)
Any effect of electromagnetic energy on a body that is not a heat-related effect.
ATP (adenosine triphosphate)
A molecule used as a temporary energy store by cells. Energy is harnessed by the hydrolysis of a phosphate group, producing ADP (adenosine diphosphate) as a product.
The progressive diminution in space of certain quantities characteristic of a propagation phenomenon.
In animals, learning is a long-lasting change that results from experience with environmental events and includes actions such as solving a maze for food. Spontaneous behaviours are actions that do not result from a response to direct stimulation and include behaviours like locomotor activity.
Biophysical mechanisms
Physical and/or chemical interactions of electric and magnetic fields with biological systems.
Blood-brain barrier
A functional concept to explain the observation that many substances transported by blood readily enter other tissues, but do not enter the brain. The barrier functions as if it were a continuous membrane lining the brain vasculature.
Calcium efflux
The release of calcium ions from a sample into a surrounding solution.
A second-messenger often used in cells to transfer signals from a surface receptor to other parts of the cell.
Any malignant, cellular tumour. The term cancer encompasses a group of neoplastic diseases in which there is a transformation of normal body cells into malignant cells. This probably involves some change in the genetic material, DNA, as a result of faulty repair of damage to the cell caused by carcinogenic agents or ionizing radiation. The altered cells pass on inappropriate genetic information to their progeny cells and begin to proliferate in an abnormal and destructive way.
A chemical, biological, or physical agent capable of producing tumor growth.
Carcinogenic process
A series of stages at the cellular level culminating in the development of cancer.
A very long molecule of DNA, complexed with protein, containing genetic information.
Circularly polarized
If the electric field is viewed as a point in space, the locus of the end point of the vector will rotate and trace out an ellipse, once each cycle.
Clastogenic effects
Microscopically visible damage or changes to chromosomes. (Truncation, translocation, deletions, sister chromatid exchange, change in chromosome number, etc.)
Clone of cells
A group of cells all derived from (and genetically identical to) a single parent cell, by the process of clonal expansion.
Continuous wave
A wave whose successive oscillations are, under steady-state conditions, identical.
Controlled environment
Controlled environments are locations where there is exposure that may be incurred by persons who are aware of the potential for exposure as a concomitant of employment, or by other cognizant persons.
The flow of electric charge.
The complete range of states or values through which a phenomenon or periodic function passes before repeating itself identically.
Toxic effects in cells.
Developmental effects
Effects in the developing offspring due to exposure before conception (either parent), prenatally, or postnatally to the time of sexual maturation. Developmental effects may be expressed at any time in the life span of the organism. Developmental effects are a subset of reproductive effects.
Deoxyribonucleic acid. The nucleic acid molecule in chromosomes that contains the genetic information.
The measurement or the determination by calculations of the internal electric field strength or induced current density, or of the specific absorption (SA) or specific absorption rate (SAR) distributions, in humans or animals exposed to electromagnetic fields and waves.
Electric dipole
Two separated electric charges; a molecule (or other structure) having the effective centres of positive and negative charges separated.
Electromagnetic energy
The energy stored in an electromagnetic field.
Electromagnetic wave
A wave characterized by variation of the electric and magnetic fields.
A technique used to separate molecules, normally according to size.
The early stages in the developing organism in which organs and organ systems are developing. For humans, this stage lasts between the second through eighth week after conception.
An observable or measurable biological, chemical, or functional event used as an index of the effect of a chemical, physical, or biological agent on a cell, tissue, organ, organism, etc.
Energy density (electromagnetic field)
The electromagnetic energy contained in an infinitesimal volume divided by that volume.
A protein whose function is that of a catalyst, e.g. lytic and lysosomal enzymes damage cell membrances and degrade cell debris, respectively.
The study of the occurrence and distribution of a disease or physiological condition in human populations and of the factors that influence this distribution.
A red blood cell, or corpuscle. One for the formed elements in peripheral blood. In most mammals mature erythrocytes are biconcave discs that have no nuclei. The cell consists mainly of haemoglobin. Erythrocyte formation takes place in the red bone marrow in the adult and in the liver spleen and bone marrow in the fetus.
An organism with a defined nucleus, organelles (mitochondria, etc.) and more complex genetic mechanisms in its cells (e.g. yeast or animal cells) (of prokaryote).
Exposure occurs whenever and wherever a person is subjected to electric, magnetic or electromagnetic fields or to contact currents other than those originating from phyiological processes in the body and other natural phenomena.
Exposure, long-term
This term indicates exposure during a major part of the lifetime of the biological system involved; it may, therefore, vary from a few weeks to many years in duration.
Exposure, partial-body
Partial-body exposure results when RF fields are substantially nonuniform over the body. Fields that are nonuniform over volumes comparable to the human body may occur due to highly directional sources, standing-waves, re-radiating sources or in the near field. See RF “Hot-spot”.
An estimate of response or quantity at a point outside the range of the experimental data. Also refers to the estimation of a measured response in a different species or by a different route than that used in the experimental study of interest (i.e., species-to-species, route-to-route, acute-to-chronic, high-to-low).
Far field region
That region of the field of an antenna where the angular field distribution is essentially independent of the distance from the antenna. In this region (also called the free space region), the field has a predominately plane-wave character, i.e., locally uniform distributions of electric field strength and magnetic field strength in planes transverse to the direction of propagation.
Cells of spindle or irregular shape responsible for fibre formation.
The number of complete cycles of a periodic waveform per unit time. Frequency if expressed in Hertz (Hz), which is equivalent to one cycle per second.
The simplest complete functional unit in a DNA molecule. A linear sequence of nucleotides in DNA that is needed to synthesize a protein and/or regulate cell function.
The genetic constitution of an individual or a cell (of phenotype) proteins with sugar (carbohydrate) groups attached, often involved in recognition or signalling mechanisms.
Gigahertz (GHz)
One billion (1,000,000,000) hertz.
A tumour composed of neurogila in any of its states of development; sometimes extended to include all intrinsic neoplasms of the brain and spinal cord.
Growth factor
A substance which stimulates a cell to grow and divide.
Hertz (Hz)
One cycle per second.
A chemical substance, formed in one organ or part of the body and carried in the blood to another organ or part where it alters the functional activity, and sometimes the structure, of one or more organs in a specific manner.
The condition of a temperature-regulating animal when the core temperature is more than one standard deviation above the mean core temperature of the species in resting conditions in a thermoneutral environment.
Immune system
The body's primary defense against abnormal growth of cells (i.e., tumours) and infectious agents such as bacteria, viruses, and parasites.
In utero
In the uterus; unborn.
In vitro
Literally means "in glass", isolated from the living organism and artifically maintained, as in a test tube or culture dish.
In vivo
Occurring within the whole living body.
Inositol phosphate pathway
An internal cell signalling pathway, involving the substrate inositol phosphate, with a role in controlling the cell cycle.
Ion channel (gate)
A protein which allows the passage of ions across a membrane.
Ion efflux
The movement of ions, charged atoms or molecules, from a sample into a surrounding solution.
The time between exposure to an injurious agent and the manifestation of a response.
A progressive, malignant disease of the blood-forming tissues, marked by an excessive number of white blood cells and their precursors.
A specific molecule which binds to a receptor, usually with high affinity.
A spherical structure, usually multilamelate, prepared from eukaryotic cell membranes which may be used as a carrier for glycoprotein antigens and drugs.
A cell of the immune system. The two subsets, T and B-cells, kill foreign cells and produce antibodies, respectively.
Any abnormal growth (neoplasm) of the lymphoid tissues. Lymphoma usually refers to a malignant growth and thus is a cancer.
Dissolution or destruction of cells.
A permanent structural change in a developing organism that may adversely affect survival, development, or function.
Harmful, virulent, life-threatening.
Maximum permissible exposure (MPE)
The rms and peak electric and magnetic field strengths, their squares, or the plane-wave equivalent power densities associated with these fields and the induced and contact currents to which a person may be exposed without harmful effect and with an acceptable safety factor.
Megahertz (MHz)
One million (1,000,000) hertz.
The biochemical reactions by which energy is made available for the use of an organism from the time a nutrient substance enters, until it has been utilized and the waste products eliminated.
A process where cells break away from a tumour and spread around the body (verb: metastasise).
Electromagnetic waves of sufficiently short wavelength that practical use can be made of waveguide and associated cavity techniques in their transmission and reception. Note: the term is taken to signify waves having a frequency range of 300 MHz-300 GHz.
A cellular organelle in which respiration occurs.
An agent which can induce cells to enter mitosis (to divide).
Cellular and nuclear division that involves duplication of the chromosomes of a parent cell and formation of two daughter cells.
(1) Mathematical model. A mathematical representation of a natural system intended to mimic the behaviour of the real system, allowing description of emphirical data, and predictions about untested states of the system.
(2) Biological model. A condition or disease in animals similar to the condition or disease in human beings.
The process of varying the amplitude, frequency, or phase of an RF carrier wave.
The appearance and structure of an organism or cell. Cells may be described by their morphology or their biochemistry. (adjective: morphological).
mRNA (messenger RNA )
An RNA copy of the genetic code for a given gene, used as a template in protein synthesis. Also known as poly-A RNA in eukaryotic cells due to a "tail" of "A" nucleotides attached to the end to aid stability, transport etc.
An agent which can induce mutation.
The process of creating mutations.
A stable, heritable change in the DNA sequence at a specific site in the genome of an organism. This constitutes a change in the genotype and, if expressed, may alter the phenotype.
Near-field region
A region generally in proximity to an antenna or other radiating structure, in which the electric and magnetic fields do not have a substantially plane-wave character, but vary considerably from point to point. The near-field region is further subdivided into the reactive near-field region, which is closest to the radiating structure and that contains most or nearly all of the stored energy, and the radiating near-field region where the radiation field predominates over the reactive field, but lacks substantial plane-wave character and is complicated in structure.
A chemical substance that transmits nerve impulses across the space between nerve endings called the synapse.
A white blood cell with important roles in the immune and inflammatory systems.
Nonionizing radiation (NIR)
Non-ionizing electromagnetic radiation incorporates all radiations and fields of the electromagnetic spectrum that do not normally have enough entergy to produce ionization in matter. NIRs have an energy per photon less than about 12eV, wavelengths longer than 100 nm, and frequencies lower than 300 THz.
A mutation of a naturally occurring gene involved in growth regulation that results in uncontrolled growth. Oncogenes are associated with the development of some forms of cancer.
The abnormally high production of protein from a gene (of amplification).
Phenotype (ic)
The physical constitution or description of an individual (or a cell) (of genotype).
Plasma membrane
The membrane surrounding animal and plant cells.
Independent circles of DNA, used by some bacteria to spread antibiotic resistance genes and by biologists to insert foreign genes into cells.
Power (surface) density
Radiant power incident on a small sphere, divided by the cross-sectional area of that sphere.
Power flux density
In radio wave propagation, the power crossing unit area normal to the direction of wave propogation. Symbol: W Unit: watts per square metre (W/m2).
The time rate at which work is done. Electrical power is proportional to the product of current and voltage.
An increase in cell or organism numbers.
The second hypothesized stage in a multistage process of cancer development. The conversion of initiated cells into tumorigenic cells.
Protein kinases
A group of enzymes which regulate the activity of proteins by phosphorylating them.
Enzymes which specifically degrade certain proteins.
Pulse amplitude
The peak value of a pulse.
Pulse duration
The interval of time between the first and last instant at which the instantaneous value of a pulse (or of its envelope if a carrier frequency pulse is concerned) reaches a specified fraction of the peak amplitude.
Pulse modulated field
An electromagnetic field produced by the amplitude modulation of a continuous wave carrier by one or more pulses.
Pulse output power
The ratio of (1) the average output power to (2) the pulse duty factor.
Pulse repetition rate
The average number of pulses in unit time during a specified period.
Radiofrequency (RF)
Any frequency at which electromagnetic radiation is useful for telecommunication. Note: in this publication the terms RF and microwave are interchangeable and refer to the frequency range 300 HZ-300 GHz.
Reproductive effects
Effects on reproduction which may include, but not be limited to, alterations in sexual behaviour, onset of puberty, fertility, gestation, parturition, lactation, pregnancy outcomes, premature reproductive senescence, or modifications in other functions that are dependent on the integrity of the reproductive system. Developmental effects are a subset of reproductive effects.
The change in amplitude as the frequency of the wave approaches or coincides with a natural frequency of the medium. The whole-body absorption of electromagnetic waves presents its highest value, i.e., the resonance, for frequencies (in MHz) corresponding approximately to 114/L, where L is the height of the individual in metres.
RF 'hot spot'
A highly localised area of relatively more intense radio-frequency radiation that manifests itself in two principal ways:
(1) The presence of intense electric or magnetic fields immediately adjacent to conductive objects that are immersed in lower intensity ambient fields (often referred to as re-radiation), and
(2) Localised areas, not necessarily immediately close to conductive objects, in which there exists a concentration of radio-frequency fields caused by reflections and/or narrow beams produced by high-gain radiating antennas or other highly directional sources. In both cases, the fields are characterised by very rapid changes in field strength with distance. RF hot spots are normally associated with very nonuniform exposure of the body (partial body exposure). This is not to be confused with an actual thermal hot spot within the absorbing body.
Ribonucleic acid. Messenger RNA, the nucleic acid in cells that is the template for the sequential ordering of amino acids during protein synthesis, is synthesized in the nucleus of the cell during the process of transcription.
Specific absorption rate (see below)
Specific absorption (SA)
The energy absorbed per unit mass of biological tissue, expressed in joules per kilogram (J/kg). SA is defined as the quotient of the incremental energy absorbed by, or dissipated in, an incremental mass contained in a volume element of a given density. SA is the time integral of specific absorption rate (SAR).
Specific absorption rate (SAR)
The rate at which energy is absorbed in body tissues, in watts per kilogram (W/kg). SAR is defined as the time derivation of the incremental energy absorbed by, or dissipated in, an incremental mass contained in a volume element of a given density. SAR is the dosimetric measure that has been widely adopted at frequencies above about 100 kHz.
Static fields
Electric and magnetic fields that do not vary in intensity or strength with time.
Temperature regulation
The maintenance of the temperature or temperatures of a body within a restricted range, under conditions involving variable, internal and/or external heat loads. Biologically, the existence of some degree of body temperature regulation by autonomic or behavioural means.
Thermal effect
In the biological tissue or system, an effect that is related to heating of the tissue through the application of electromagnetic fields, and that can occur through other forms of heating.
Thermogenic levels
Power densities of RF that produce a measurable temperature increase in the exposed object.
A radiolabelled nucleoside used to quantitatively follow the synthesis/replication of DNA.
Time-varying fields
Electric and magnetic fields that change in intensity or strength with time. Examples include 60 Hz, modulated, and transient fields.
The cellular process in which messenger RNA is synthesized, i.e., the process in which the genetic information in DNA is copied.
The genetic alteration of a cell so that it will form a tumour if injected into a suitable host animal. Transformed cells also exhibit characteristic growth changes in culture (cf immortalisation).
The assembly of amino acids into a protein, using the information in RNA.
A swelling caused by the uncontrolled growth of cells. Tumours are also called neoplasms, which means that they are composed of new and actively growing tissue. Their growth is faster than that of normal tissue, continuing after cessation of the stimuli that evoked the growth.
Tumour suppressor gene
A normal cellular gene involved in regulating cell behaviour. Mutations can contribute to cancer in a recessive fashion.
Uncontrolled environment
Uncontrolled environments are locations where there is the exposure of individuals who have no knowledge or control of their exposure.
The distance between two successive points of a periodic wave in the direction of propagation, in which the oscillation has the same phase. Symbol l Unit: metre (m).
Whole-body exposure
Pertains to the case in which the entire body is exposed to the incident electromagnetic energy or the case in which the cross section (physical area) of the body is smaller than the cross section of the incident radiation beam.
"Windowed" responses
Effects found within bands or ranges of frequency or intensity separated by bands or ranges without effect; nonlinear exposure-response relations.


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