IEEE Committee on Man and Radiation-COMAR Technical Information Statement: Health and Safety Issues Concerning Exposure of the General Public to Electromagnetic Energy from 5G Wireless Communications Networks.

This COMAR Technical Information Statement (TIS) addresses health and safety issues concerning exposure of the general public to radiofrequency (RF) fields from 5G wireless communications networks, the expansion of which started on a large scale in 2018 to 2019. 5G technology can transmit much greater amounts of data at much higher speeds for a vastly expanded array of applications compared with preceding 2-4G systems; this is due, in part, to using the greater bandwidth available at much higher frequencies than those used by most existing networks. Although the 5G engineering standard may be deployed for operating networks currently using frequencies extending from 100s to 1,000s of MHz, it can also operate in the 10s of GHz where the wavelengths are 10 mm or less, the so-called millimeter wave (MMW) band. Until now, such fields were found in a limited number of applications (e.g., airport scanners, automotive collision avoidance systems, perimeter surveillance radar), but the rapid expansion of 5G will produce a more ubiquitous presence of MMW in the environment. While some 5G signals will originate from small antennas placed on existing base stations, most will be deployed with some key differences relative to typical transmissions from 2-4G base stations. Because MMW do not penetrate foliage and building materials as well as signals at lower frequencies, the networks will require "densification," the installation of many lower power transmitters (often called "small cells" located mainly on buildings and utility poles) to provide for effective indoor coverage. Also, "beamforming" antennas on some 5G systems will transmit one or more signals directed to individual users as they move about, thus limiting exposures to non-users. In this paper, COMAR notes the following perspectives to address concerns expressed about possible health effects of RF field exposure from 5G technology. First, unlike lower frequency fields, MMW do not penetrate beyond the outer skin layers and thus do not expose inner tissues to MMW. Second, current research indicates that overall levels of exposure to RF are unlikely to be significantly altered by 5G, and exposure will continue to originate mostly from the "uplink" signals from one's own device (as they do now). Third, exposure levels in publicly accessible spaces will remain well below exposure limits established by international guideline and standard setting organizations, including ICNIRP and IEEE. Finally, so long as exposures remain below established guidelines, the research results to date do not support a determination that adverse health effects are associated with RF exposures, including those from 5G systems. While it is acknowledged that the scientific literature on MMW biological effect research is more limited than that for lower frequencies, we also note that it is of mixed quality and stress that future research should use appropriate precautions to enhance validity. The authorship of this paper includes a physician/biologist, epidemiologist, engineers, and physical scientists working voluntarily and collaboratively on a consensus basis.

Microwave hearing: evidence for thermoacoustic auditory stimulation by pulsed microwaves.

Acoustic transients can be thermally generated in water by pulsed microwave energy. The peak pressure level of these transients, measured within the audible frequency band as a function of the microwave pulse parameters, is adequate to explain the "clicks" heard by people exposed to microwave radiation.

Bounds on "bound water": transverse nuclear magnetic resonance relaxation in barnacle muscle.

Relatively mobile protons that do not exchange with D2O exist in barnacle muscle cells. These are not part of the nonfreezing "bound water" that does exchange. Ninety-seven percent of the muscle water exhibits a single transverse relaxation time of 35 milliseconds: one water molecule per thousand, which is briefly and irrotationally bound, will produce the observed relaxation properties.

Genetic Regulation of Development in Sorghum bicolor (IX. The ma3R Allele Disrupts Diurnal Control of Gibberellin Biosynthesis).

The diurnal regulation of gibberellin (GA) concentrations in Sorghum bicolor was studied in a mutant lacking a light-stable 123-kD phytochrome (ma3Rma3R), wild-type (ma3ma3,Ma3Ma3), and heterozygous (ma3ma3R) cultivars. GAs were determined in shoots of 14-d-old plants by gas chromatography-selected ion-monitoring-mass spectrometry. GA12 levels fluctuated rhythmically in Ma3Ma3, ma3ma3, and,ma3Rma3R; Peak levels occured 3 to 9 h after lights-on. In some experiments, GA53 levels followed a similar pattern. There was no rhythmicity in levels of GA19 and GA8 in any genotype. In ma3ma3 and Ma3Ma3, GA20 levels increased at lights-on, peaked in the afternoon, and decreased to minimum levels in darkness. In ma3Rma3R, peak GA20 levels occured at lights-on, 9 h earlier than in the wild-type genotypes. The pattern for GA1 levels closely followed GA20 levels in all cultivars. One copy of ma3 restored near wild-type regulation of GA20 levels. GA rhythms persisted in 25-d-old ma3ma3 plants. Since absence of the 123-kD phytochrome disrupted diurnal regulation of the GA19 -> GA20 step, the ma3Rma3R genotype may be viewed as being phase shifted in the rhythmic levels of GA20 and GA1 rather than as simply overproducing them.

Genetic Regulation of Development in Sorghum bicolor (VIII. Shoot Growth, Tillering, Flowering, Gibberellin Biosynthesis, and Phytochrome Levels Are Differentially Affected by Dosage of the ma3R Allele.

Sorghum [Sorghum bicolor (L.) Moench] homozygous for ma3R lacks a type II, light-stable phytochrome of 123 kD and has a number of phenotypic characteristics consistent with the absence of functional phytochrome B. We have used plants heterozygous at Ma3 (Ma3/ma3R and ma3/ma3R) to determine the effect of dosage of ma3R on plant growth, flowering, gibberellin (GA) levels, and content of the 123-kD phytochrome. Both Ma3/ma3R and ma3/ma3R produced the same number of tillers per plant as their respective homozygous non-ma3R parents. Height of the heterozygotes was intermediate between the homozygous parents, although it was more similar to the non-ma3R genotypes. In both field and growth-chamber environments, the timing of floral initiation and anthesis in the heterozygotes also was intermediate, again more similar to non-ma3R plants. In Ma3/ma3R, levels of GA53, GA19, GA20, and GA1 were almost exactly intermediate between levels detected in Ma3/Ma3 and ma3R/ma3R plants. Immunoblot analysis indicated that there was less of the 123-kD phytochrome in Ma3/ma3R than in homozygous Ma3, whereas none was detected in ma3R/ma3R. The degree of dominance of Ma3 and ma3 over ma3R varies with phenotypic trait, indicating that mechanisms of activity of the 123-kD phytochrome vary among the biochemical processes involved in each phenotypic character. Although the heterozygotes were similar to homozygous Ma3 and ma3 plants in growth and flowering behavior, Ma3/ma3R contained 50% less of the bioactive GA (GA1) than non-ma3R genotypes. Thus, sensitivity to endogenous GAs also may be regulated by the 123-kD phytochrome. To fully regulate plant growth and development, two copies of Ma3 or ma3 are required to produce sufficient quantities of the light-stable, 123-kD phytochrome.

Mobile phones, mobile phone base stations and cancer: a review.

There have been reports in the media and claims in the courts that radiofrequency (RF) emissions from mobile phones are a cause of cancer, and there have been numerous public objections to the siting of mobile phone base antennas because of a fear of cancer. This review summarizes the current state of evidence concerning whether the RF energy used for wireless communication might be carcinogenic. Relevant studies were identified by searching MedLine with a combination of exposure and endpoint terms. This was supplemented by a review of the over 1700 citations assembled by the Institute of Electrical and Electronics Engineers (IEEE) International Committee on Electromagnetic Safety as part of their updating of the IEEE C95.1 RF energy safety guidelines. Where there were multiple studies, preference was given to recent reports, to positive reports of effects and to attempts to confirm such positive reports. Biophysical considerations indicate that there is little theoretical basis for anticipating that RF energy would have significant biological effects at the power levels used by modern mobile phones and their base station antennas. The epidemiological evidence for a causal association between cancer and RF energy is weak and limited. Animal studies have provided no consistent evidence that exposure to RF energy at non-thermal intensities causes or promotes cancer. Extensive in vitro studies have found no consistent evidence of genotoxic potential, but in vitro studies assessing the epigenetic potential of RF energy are limited. Overall, a weight-of-evidence evaluation shows that the current evidence for a causal association between cancer and exposure to RF energy is weak and unconvincing. However, the existing epidemiology is limited and the possibility of epigenetic effects has not been thoroughly evaluated, so that additional research in those areas will be required for a more thorough assessment of the possibility of a causal connection between cancer and the RF energy from mobile telecommunications.

IEEE Committee on Man and Radiation (COMAR) Technical Information Statement "exposure of medical personnel to electromagnetic fields from open magnetic resonance imaging systems".

Open magnetic resonance imaging (MRI) systems enable performing image-guided medical procedures for long periods of time very close to, or inside, the patient imaging area. Medical personnel can be exposed to relatively high static, gradient, and radiofrequency fields compared to most other MRI systems. The Committee on Man and Radiation of the Institute of Electrical and Electronics Engineers calculated or used existing data on magnetic flux densities and field strengths in or near the patient area to assess occupational exposure levels. Potential exposures to each field type were analyzed and compared to relevant values specified in international exposure limits including those of the Institute of Electrical and Electronics Engineers and the International Commission on Nonionizing Radiation Protection. Exposures of the head or torso of a worker to gradient fields near the center of the patient-imaging area can exceed most exposure limits even for times less than a second. Exposures to radiofrequency fields can exceed limits if sustained exposures (minutes or more) occur to parts of the body. Static magnetic fields used by present Open MRI systems are below exposure limits of all of the standards that address these fields. Overall results of this study suggest that manufacturers and others who program or operate Open MRI systems should take care to ensure that operating parameters produce exposures that comply with the relevant exposure limits. Also, since field levels fall off rapidly with increasing distance, user practices may be implemented that reduce exposures significantly.

Whole-body impedance--what does it measure?

Although the bioelectrical impedance technique is widely used in human nutrition and clinical research, an integrated summary of the biophysical and bioelectrical bases of this approach is lacking. We summarize the pertinent electrical phenomena relevant to the application of the impedance technique in vivo and discuss the relations between electrical measurements and biological conductor volumes. Key terms in the derivation of bioelectrical impedance analysis are described and the relation between the electrical properties of tissues and tissue structure is discussed. The relation between the impedance of an object and its geometry, scale, and intrinsic electrical properties is also discussed. Correlations between whole-body impedance measurements and various bioconductor volumes, such as total body water and fat-free mass, are experimentally well established; however, the reason for the success of the impedence technique is much less clear. The bioengineering basis for the technique is critically presented and considerations are proposed that might help to clarify the method and potentially improve its sensitivity.

The effect of sex-allocation biasing on the evolution of worker policing in hymenopteran societies.

Mutual policing is thought to be important in conflict suppression at all levels of biological organization. In hymenopteran societies (bees, ants, and wasps), multiple mating by queens favors mutual policing of male production among workers (worker policing). However, worker policing of male production is proving to be more widespread than predicted by relatedness patterns, occurring in societies headed by single-mated queens in which, paradoxically, workers are more related to the workers' sons that they kill than the queen's sons that they spare. Here we develop an inclusive-fitness model to show that a second reproductive conflict, the conflict over sex allocation, can explain the evolution of worker policing contrary to relatedness predictions. Among ants, and probably other social Hymenoptera, workers kill males to favor their more related sisters. Importantly, males are killed at the larval stage, presumably because workers cannot determine the sex of queen-laid eggs. Sex-allocation biasing favors worker policing because policing removes some males (the workers' sons) at low cost at the egg stage rather than at higher cost at the larval stage. Our model reveals an important interaction between two reproductive conflicts in which the presence of one conflict (sex allocation) favors the suppression of the other (male production by workers).

Convergent evolution of worker policing by egg eating in the honeybee and common wasp.

Mutual policing, where group members suppress each others' reproduction, is hypothesized to be important in the origin and stabilization of biological complexity. Mutual policing among workers in social insects can reduce within-colony conflict. However, there are few examples. We tested for worker policing in the common wasp Vespula vulgaris. Workers rapidly removed worker-laid eggs but left most queen-laid eggs (four out of 120 worker eggs versus 106 out of 120 queen eggs remained after 1h). Ovary dissection (1150 workers from six colonies) revealed that a small but significant number of workers have active ovaries (4%) equivalent to approximately five to 25 workers per colony. Consistent with effective policing of worker reproduction, microsatellite analysis of males (270 individuals from nine colonies) detected no workers' sons. Worker policing by egg eating has convergently evolved in the common wasp and the honeybee suggesting that worker policing may have broad significance in social evolution. Unlike the honeybee, relatedness patterns in V. vulgaris do not explain selection for policing. Genetic analysis (340 workers in 17 nests) revealed that workers are equally related to the queen's and other workers' sons (worker-worker relatedness was 0.51 +/- 0.04, 95% confidence interval). Worker policing in V. vulgaris may be selected due to the colony-level benefit of conflict suppression.

Dielectric properties of tissues and biological materials: a critical review.

We critically review bulk electrical properties of tissues and other biological materials, from DC to 20 GHz, with emphasis on the underlying mechanisms responsible for the properties. We summarize the classical principles behind dielectric relaxation and critically review recent developments in this field. Special topics include a summary of the significant recent advances in theories of counterion polarization effects, dielectric properties of cancer vs. normal tissues, properties of low-water-content tissues, and macroscopic field-coupling considerations. Finally, the dielectric properties of tissues are summarized as empirical correlations with tissue water content in other compositional variables; in addition, a comprehensive table is presented of dielectric properties. The bulk electrical properties of tissues are needed for many bioengineering applications of electric fields or currents, and they provide insight into the basic mechanisms that govern the interaction of electric fields with tissue.

The UHF and microwave dielectric properties of normal and tumour tissues: variation in dielectric properties with tissue water content.

Dielectric measurements have been made on various soft tumour and normal tissues between 0.01 and 17 GHz at body temperature. At microwave frequencies above 1-5 GHz, the tissue dielectric properties can be fitted to Debye equations with the same relaxation frequency (25 GHz) as found for pure water at 37 degrees C. The tissue dielectric properties correlate well with their water contents. The conductivity of the tissue at 0.1 GHz (which is close to that of the cytoplasm itself) increases with the volume fraction of water in the tissue, in a manner consistent with that previously observed in proteins suspended in electrolyte solution. The contribution of the tissue water to the tissue dielectric permittivity at frequencies below 1 GHz is fitted by a function of water content different to that describing the conductivity data. Empirical equations that may be used to predict the dielectric properties of other soft tissues within this wide frequency range are suggested.

Dielectric properties of low-water-content tissues.

The dielectric properties of two low-water-content tissues, bone marrow and adipose tissue, were measured from 1 kHz to 1 GHz. From 1 kHz to 13 MHz, the measurements were performed using a parallel-plate capacitor method. From 10 MHz to 1 GHz, a reflection coefficient technique using an open-ended coaxial transmission line was employed. The tissue water contents ranged from 1 to almost 70% by weight. The dielectric properties correlate well with the values predicted by mixture theory. Comparison with previous results from high-water-content tissues suggests that bone marrow and adipose tissues contain less motionally altered water per unit dry volume than do the previously studied tissues with lower lipid fractions. The high degree of structural heterogeneity of these tissues was reflected in the large scatter of the data, a source of uncertainty that should be considered in practical applications of the present data.