Evaluation of the Potential Biological Effects of the

60-GHz Millimeter Waves Upon Human Cells

Maxim Zhadobov, Member, IEEE, Christophe Nicolas Nicolaz, Ronan Sauleau, Senior Member, IEEE, Fabienne Desmots, Daniel Thouroude, Denis Michel, and Yves Le Dréan

IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 57, NO. 10, OCTOBER 2009 2949

Abstract—We investigate potential biological effects of low-power millimeter-wave radiation on human cell viability and intracellular protein homeostasis. A specific exposure system allowing to perform far-field exposures with power densities close to those expected from the future wireless communications in the 60-GHz band has been developed and characterized. Specific absorption rate (SAR) values were determined for the biosamples under test using the FDTD method. It was shown that millimeter-wave radiation at 60.42 GHz and with a maximum incident power density of mW/cm does not alter cell viability, gene expression, and protein conformation.

Index Terms—Bioelectromagnetics, biological effects, millimeter waves, numerical dosimetry, wireless communications.

2009 Zhadobov IEEE_PDF

Original Source

From the bioelectromagnetic point of view, the human body has never been exposed in natural conditions to radiations in the 60-GHz band since these frequencies, which correspond to the peak of molecular oxygen absorption, are strongly attenuated in the atmosphere [13]. Furthermore, a large number of spectral lines of molecular groups containing carbon or oxygen molecules are located around 60 GHz. Moreover, these frequencies have also been used in several countries for biomedical purposes [14], thereby suggesting that molecular interactions between the millimeter waves and the human body are possible. 

A few theories were proposed to explain potential biological effects of millimeter waves [15]. A number of experimental efforts have been also undertaken and have shown that millimeter-wave radiations may interfere with several cellular processes under certain exposure conditions. For instance, it was demonstrated that these radiations can induce changes in gene expression [16]. Additionally, millimeter waves were found to reduce tumor metastasis [17] and protect cells from toxicity of anticancer medicines [18]. It was also reported that cellular metabolism and cell proliferation can be affected by exposure to low-power millimeter waves [19]. Furthermore, it was recently demonstrated that these radiations can modify the structural state of phospholipids within biomembranes [20], [21]. However, there remains a crucial lack in identification of exact cellular targets of millimeter waves, and today there is no well-established scientific interpretation for the observed effects. Within this context, from the general public safety viewpoint, it is important to investigate the possible biological effects of low-power communication systems in the 60-GHz band before their wide, near-future deployment within domestic and professional environments. 

Various environmental factors can cause significant changes in the organization and conformation of biological macro- molecules. DNA and proteins are the cellular components most affected by variations of physical and chemical conditions. DNA damages are induced by high-energy treatments (e.g., ionizing radiations), whereas proteins are particularly fragile and affected by relatively weak disruptive treatments, such as heat. Millimeter waves are nonionizing radiations and, as expected, it was shown that they are not genotoxic [22]. Nevertheless, physical principles do not exclude that these radiations might alter the protein conformations or cause a proteotoxic stress. Denaturation of proteins due to environmental insults may have many biological consequences. It may lead to various cellular dysregulations, such as defects in enzymatic activities, signal transduction, cellular organization, or cell growth. Finally, prolonged stress conditions may also affect the cellular viability and trigger apoptosis, a form of programmed cell death that can lead to severe diseases when deregulated. Consistently, cells have developed sophisticated molecular systems to sense and respond rapidly to changes in their environment [23]. In the presence of stress conditions, cells express specific chaperones and stress factors to cope with the accumulation of misfolded proteins. These factors also have protective functions that allow cells to survive. 

Consequently, a relevant and accurate way for the investigation of biological effects of millimeter waves at the cellular level consists of studying and quantifying the most sensitive cellular responses to stress as indicators (biomarkers) of cellular homeostasis. As cellular stress is a multistep process, we developed and applied several assay systems to assess potential stress induction after exposure. Our methodology is summarized in Fig. 1. Several complementary aspects of the cell physiology have been considered in this work, starting with relatively general characterization of cellular viability (assay 1) and then investigating potential subcellular modifications at the level of protein conformation (assay 2) and gene expression (assay 3). 

As human skin is the primary target for the millimeter waves, we used the immortalized keratinocytes HaCaT cells derived from human epidermis [24]. Additionally, to validate and compare the results obtained using keratinocyte cells, the human astrocytoma glial cell line U-251 MG was used as a relevant and well-characterized biological model to investigate cellular stress. 

This paper is organized as follows. We describe in Section II the structure and characteristics of our exposure system and provide numerical dosimetry data for the exposed biosamples. Some details about the biological protocols are also provided at the end of this section. The experimental results of the biological tests after exposure of human cells at 60.42 GHz are described in Section III. Finally, discussions and conclusions are given in Section IV. 

II. EXPERIMENTAL SYSTEMS AND NUMERICAL DOSIMETRY 

In our experiments, the biological samples were placed in standard 6-well or 96-well tissue culture dishes and were exposed or sham-exposed to low-power millimeter waves. In this section, the exposure system and experimental setup are described. Then, numerical dosimetry data on the specific absorption rate (SAR) within the exposed biological samples are provided. Finally, some specific characteristics of the con- sidered cells and bioassays used to quantify potential bioeffects are given. 

A. Experimental Setup 

A narrowband exposure system for in vitro studies has been specifically developed for human cells exposure under far-field conditions. Fig. 2 schematically represents the three main sub- units of this system, namely the signal generation subunit, the frequency control subunit, and the exposure chamber. 

A low-power CW signal is generated by a Gunn oscillator at the center frequency GHz. This frequency value coincides with the maximal oxygen-induced absorption peak in V-band. A mechanical tuning system enables one to shift the resonant frequency by MHz around . This signal is am- plified and transmitted toward a 17-dB-gain pyramidal horn an- tenna with aperture dimensions mm mm through a set of WR-15 rectangular waveguides and a directional cou- pler. In this work, the output power equals 180 mW; this corresponds to a maximum incident power density (IPD) of mW/cm at the center of the tissue culture plate. This value coincides with the general public exposure limit established by international guidelines and recommendations [25]. 

The radiated power was carefully checked before and after each exposure. The use of a Gunn oscillator guarantees a very satisfactory frequency stability of the output signal as highlighted in Fig. 3, GHz . This also ensures its location within the peak region of oxygen absorption. 

B. Numerical Dosimetry 

The exposure levels of biological samples at millimeter waves are typically characterized by two parameters, namely the IPD and the SAR values. IPD data have been previously reported for 6-well and 24-well tissue culture plates illuminated by a pyra- midal horn antenna [26]. Here, we mainly focus on determina- tion of the average SAR for the two exposure scenarios corre- sponding to the three assays defined in Fig. 1: 1) exposure of cell monolayers located in 6-well or 96-well culture plates (assays 1 and 3); 2) exposure of purified protein solutions in a 96-well tissue culture plate (assay 2). 

1) Average SAR in Cell Monolayers: The analysis of gene expression modifications after exposure at 60.42 GHz (Section III-C) was performed using standard 6-well culture plates made of polystyrene. In the experiments, each plate was illuminated under far-field conditions by a pyramidal horn antenna 27 cm apart, as illustrated in Fig. 2. The cell monolayer is located at the bottom of each well and is covered by a culture medium whose height is equal to 1 cm. In the modeling, the thickness of the monolayer was assumed to be m. Previ- ously, it was shown that the SAR within the cell layers in the tissue culture plates is not critical to the thickness variations of the monolayer ranging from 10 to 30 m [27]. The wells and culture plates are schematically represented in Fig. 4. 

The dielectric properties of the cell monolayer and culture medium were determined applying Maxwell’s mixture equa- tion to the free-water permittivity data. The corresponding data are available in [27] from 30 to 100 GHz. They are given at 60.42 GHz in Table I. 

The distribution of the electromagnetic field within each of the six wells was computed using the FDTD method (XFDTD software from REMCOM Inc.) that proved to be very well adapted for biomedical electromagnetic dosimetry [28]–[30]. 

All simulations were performed using adaptive rectangular mesh with a cell size ranging from m up to
( m in free space), where and are the wavelength in the considered substructure and the smallest dimension of this substructure, respectively. We assumed the incident field to be a normally incident, linearly-polarized plane wave. Each com- putation was performed for single-well applying boundary con- ditions as defined in Fig. 5. 

The average SAR over the cell monolayer volume was deter- mined from the electric field values, electric conductivity, and average mass density of the cells g/cm (Fig. 5). This modeling strategy has already been validated experimen- tally using infrared thermometry for 24-well plates [27]. As the 

four corner wells and two central wells are symmetrical from the electromagnetic point of view, their average SAR is the same. 

The SAR was also computed for monolayers located in 96-well tissue culture plates. Such plates have been employed to study cell viability (Section III-A). Here, taking into ac- count the large number of wells, periodic boundary conditions were applied at four lateral sides of a well. For a peak IPD of 

mW/cm , the average SAR ranges from 26.2 (center well) down to 13.7 W/kg (corner wells). 

2) Average SAR in Purified Protein Solutions: The direct ef- fect on possible protein conformation changes after exposure to the millimeter waves was studied using a purified protein so- lution located in a 96-well tissue culture plate (Section III-B). Each well was filled with L of protein solution forming a cylinder whose height and diameter equal 1.8 and 6 mm, respec- tively. The volume of the solution was carefully chosen to get enough material for the biological tests and, at the same time, to ensure a maximum variation of the average SAR at different heights of the solution smaller than dB with respect to the averaged SAR over the total volume of the solution. 

The relative permittivity and electric conductivity of our so- lution were determined as explained in Section II-B1; they are given in Table I. It is important to note that due to the diffraction, multiple reflections, and mutual coupling between neighboring wells, the protein solution was also partly exposed from the lat- eral sides and from the top that increases the averaged over the solution volume SAR. It is also worthwhile to mention that due to the Brownian motion and convection, the protein solution is constantly mixed, which ensures more homogeneous exposure conditions. 

The electromagnetic problem was solved using the FDTD method by applying periodic boundary conditions on opposite lateral sides of a single well. Depending on the well location in the culture plate, the averaged SAR over the solution volume was found to be in the range W/kg. The resulting averaged SAR values are much smaller than for cell mono- layers (Fig. 5) since the penetration depth of millimeter waves is smaller than the protein solution height [27]. 

C. Cell Culture and Bioassays 

1) Cell Culture: Immortalized HaCaT cells [24], derived from human epidermis, were kindly provided by Dr. M-D. Galibert-Anne (University of Rennes 1, Rennes, France), and they were grown in Dubelcco’s modified Eagle medium (Gibco/Life Technologies), supplemented with 10% of Fœtal Calf Serum, 100 units/mL penicillin, g/mL streptomycin, and g/ml amphotericin (Gibco/Life Technologies). 

We also used human astrocytoma cell line U-251 MG [31], as they are highly sensitive and respond with great efficiency to environmental perturbations. Cell culture of U-251 MG was performed as described previously [32], using the same culture medium as for the HaCaT cells. 

Both cell lines were maintained at C under 5% in the air. The cell cycle durations for HaCaT and U-251 MG cells are 20 and 24 h, respectively. Cells were spread in order to have around 60%–70% of confluence at the end of the expo- sure experiments. 

2) Bioassays: As summarized in Fig. 1, three series of bi- ological assays were carried out after exposure to millimeter waves: 1) study of cell growth and viability; 2) analysis of direct protein denaturation; 3) determination of possible modifications of gene expression. In each case, multiple exposures were per- formed to ensure appropriate statistics. The corresponding ex- perimental results are given in Section III. 

Cell growth and viability (assay 1 in Fig. 1) were measured using the “cell growth determination kit” from Sigma-Aldrich. Cell viability was determined by measurements of cellular metabolic activity, which is proportional to the number of viable cells in the culture dish. This method is based on the cleavage of the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetra- zolium bromide (also known as MTT) by the mitochondrial dehydrogenases of viable cells. Cells spread in a 96-well plate were sham-exposed or exposed to 60.42 GHz radiation for 24 h. The cells were incubated with the MTT reagent for the last 3 h of the culture. Cleavage by metabolically active cells leads to the formation of purple formazan crystals. The latter were solubilized and measured by a spectrophotometric method, according to the manufacturer’s recommendations. 

The direct protein denaturation was studied using in vitro luciferase (Luc) assay (assay 2 in Fig. 1). The cDNA encoding the luciferase enzyme from firefly (Photinus pyralis) was inserted into the pGEX-3X plasmid (GE Heathcare Bio-Sci- ences, Uppsala, Sweden), which corresponds to a Glutathione S-Transferase (GST) expression vector. The presence and the orientation of the insert within the recombinant plasmid were verified by restriction enzyme analysis. E. coli BL21 bacteria cells were transformed with the resulting pGEX-Luc expression vector and selected colonies were tested for pro- tein production. Recombinant GST-Luc fusion protein was expressed and purified as described in GE Healthcare Life Sciences protocols [33]. Briefly, whole cell lysates were ob- tained from transformed bacteria grown at C and induced with 0.5 mM IPTG for 5 h. Soluble proteins were separated from insoluble materials by centrifugation. Then, the GST-Luc fusion protein was purified by affinity chromatography using glutathione-agarose beads. The purified GST-Luc ( ng L, 

580 nM) was incubated in L of phosphate buffered saline (PBS) in a 96-well plate. The purified GST-Luc was exposed or sham-exposed to millimeter waves for 15 min at C. Its enzymatic activity was then determined in a luminometer using a luciferase assay system kit (Promega). As a positive control, thermal denaturation of luciferase (10 min at C) was performed under the same conditions. 

Finally, to assess potential modifications of gene expression (assay 3 in Fig. 1), we used reverse transcription polymerase chain reaction (RT-PCR) analysis. Total RNA from U-251 MG or HaCaT cells, exposed or sham-exposed for 24 h, were prepared and reverse-transcribed as previously described [32]. The mRNA expression levels of stress-induced survival factors (HSP70, BiP) were measured by real-time PCR and normalized as explained in [34]. 

Statistical significance of the performed essays was evaluated by using Student’s test within the Minitab 15.1.1 software. 

was considered as a criterion of nonsignificance. 

III. RESULTS 

In this section, we present the experimental results on the po- tential modifications induced at cellular (viability of cells) and subcellular (protein conformation and gene expression) levels after cell exposure to low-power millimeter-waves. 

A. Viability of Cells 

To address the potential cytotoxicity of millimeter-wave ra- diation, the MTT assay was performed after 24 h of exposure to 60.42 GHz (Fig. 6). 

As a positive control demonstrating the decrease of cell vi- ability as a reaction to stress, the MTT test was performed for U-251 MG cells in the presence of cell death inductors, namely 

M staurosporine (Stauro: a potential anticancer drug that provokes apoptosis) or M cadmium (Cd: a highly toxic heavy metal). Under these conditions, the cell viability was decreased by a factor larger than 6 [Fig. 6(a)]. 

Then, the cell viability was compared for the exposed ( mW, mW/cm , W/kg) or sham-exposed cells mW . Our results are given in Fig. 6(b). They clearly show that, in contrast to the positive con- trols, millimeter-wave radiation does not decrease cell viability 

or cellular proliferation for the cell lines used in our study. 

Fig. 7. Protein luciferase activity after exposure or sham-exposure to 60.42-GHz radiation. (a) To demonstrate how sensitive the luciferase enzyme to denaturing conditions is, a heat shock treatment ( C, 10 min) was performed and compared to control ( C, 10 min). (b) Activity of exposed at 60.42 GHz and sham-exposed samples ( C, 15 min). Data provided for four samples. 

B. Effects on Protein Conformation 

Purified protein luciferase dissolved in saline solution was ex- posed to 60.42 GHz or sham-exposed. The choice of the bio- logical system under test was determined by its extremely high sensitivity to various physical and chemical conditions. 

As a positive control, an in vitro denaturation experiment was performed, demonstrating that a short incubation at C is suf- ficient to entirely denature the luciferase [Fig. 7(a)]. 

The protein solution was exposed or sham-exposed for 15 minat C( mW, mW/cm, 

W/kg). This experiment was restricted to very short-term exposure time as purified luciferase is extremely fragile and its prolonged incubation may rapidly abolish its enzymatic activity. Our experimental results [Fig. 7(b)] show that millimeter waves do not significantly change luciferase activity under the consid- ered exposure conditions. Taking into account relatively non- homogeneous distribution of the SAR in the protein solution, further complementary investigations in this direction might be useful. 

C. Effects on Gene Expression 

Finally, we studied whether prolonged exposure to mil- limeter-wave radiation has a proteotoxic effect strong enough to trigger cellular adaptive response and overexpression of stress factors. To address this issue, we selected two stress-biomarker genes, namely the heat shock protein 70 (HSP70) and the immunoglobulin heavy-chain binding protein (BiP). These two genes are highly inducible by cellular stresses and can be used as perfect indicators of cellular aggression [35], [36]. To mon- itor the cellular stress level, cells were exposed to 60.42 GHz ( mW, mW/cm, W/kg for central well, W/kg for corner well) or sham-exposed for 24 h. Then, total RNA was purified for quan- titative real-time PCR analysis. This technique is considered nowadays as the most sensitive and accurate one for gene expression measurement. 

For the positive control, cells were incubated for 3 h 30 min at C. The expression of HSP70 and BiP increased 2.2- and 9.2-fold, respectively, after heat shock treatment [Fig. 8(a)]. 

Our experimental results have shown that the mRNA levels of HSP70 and BiP do not increase after exposure of the cells to 

IV. DISCUSSIONS AND CONCLUSION 

In this study, we investigated potential biological effects of millimeter waves at 60.42 GHz upon human cells (skin cells and glial cells). A specific exposure system for in vitro studies was developed and characterized. The output power level was se- lected to achieve superficial power densities on biological sam- ples close to those typically expected from the future wireless communication systems in the 60-GHz band. 

First, the average SAR values within cell monolayers or protein solutions used in our bioelectromagnetic experiments were computed with the FDTD method. The numerical results demonstrated that, for the maximum IPD of mW/cm (expo- sure limit for general population), the average SAR values range between 17 and 21.4 W/kg and between 13.7 and 26.2 W/kg for 6-well and 96-well tissue culture plates, respectively. The average SAR W/kg for purified protein solutions in 96-well plates is 4.7 times lower than for cell monolayers due to the shallow penetration of millimeter waves in the solution. 

Then, various biological assays were defined and imple- mented to assess the effects of low-power millimeter wave at the cellular, subcellular, and molecular levels. Our experimental results demonstrated that, for the IPD lower than mW/cm , exposure to millimeter waves does not modify cell growth and viability. Furthermore, the experiments did not show any statistically significant effect on protein conformation and adaptive gene expression. These data confirm recent studies showing that, if care is taken to avoid thermal effects, exposures to low-power millimeter-wave have no proteotoxic effects and do not induce protein chaperones expression [26], [34], [37]. 

In conclusion, our results indicate that exposure to low-power radiations around 60 GHz does not cause any significant effect. However, they do not exclude a possibility of existence of local subcellular effects or effects potentially induced by prolonged exposures. Moreover, we cannot neglect possible synergistic ef- fects and eliminate the possibility that other exposure param- eters, like frequency, exposure time, or field polarization may have effects on biosystems. Therefore, additional gene markers and radiation parameters should be further analyzed for an ex- tensive investigation of the potential biological effects of mil- limeter waves. 

 



Fixed Wireless Communications at 60GHz Unique Oxygen Absorption Properties

April 10, 2001

Fixed Wireless Communications at 60GHz Unique Oxygen Absorption Properties

by Shigeaki (Shey) Hakusui, President, Harmonix Corporation
The demand for bandwidth is growing at a rapid pace. International Data Corporation projects that Internet commerce in the United States will grow from $74 billion in 1999 to $708 billion in 2003, with the number of computer users more than doubling from 81 million to 177 million in the U.S. alone. Due to the tremendous expected growth, reliable fiber optic networks must be installed quickly.

In the United States, less than five percent of all commercial office buildings have access to fiber cables. With the high costs to install physical fiber, up to $250,000 per mile, many stopgap techniques, including ISDN, DSL, satellite and microwave communications links, have been deployed to overcome this “last mile” challenge. However, these techniques pose only temporary solutions, as ISDN and DSL require bandwidth from physical mediums that were not designed for Internet use, and available licensed microwave frequencies, 900MHz to 40GHz, and satellite frequencies, 6GHz to 30GHz, are limited.

Short haul, high-density deployments of wireless communications devices are required in metropolitan areas and business parks throughout the United States. Most often, office buildings though not physically linked to the fiber backbone are within one half mile of a local fiber trunk. Wireless communication devices operating at higher frequencies, such as 60GHz, allow businesses to link to the fiber easily, without the cost and time delays associated with physical fiber installation.

Due to the increased bandwidth demands and the scarcity of microwave frequency allocations, the wireless communications industry is beginning to focus on higher, previously unallocated portions of the spectrum in the millimeter wave frequencies from 40GHz to 300GHz. Due to the high levels of atmospheric RF energy absorption, the millimeter wave region of the RF spectrum is not usable in long haul, wireless communications segments. However, for short haul, “last mile” segments, the expanded RF data bandwidth available in the millimeter wave region makes it ideal for interference free, fiber speed connectivity.

Figure 1 illustrates the atmospheric absorption for millimeter wave frequencies.
At the millimeter wave frequency of 60GHz, the absorption is very high, with 98 percent of the transmitted energy absorbed by atmospheric oxygen. While oxygen absorption at 60GHz severely limits range, it also eliminates interference between same frequency terminals.

 

Figure 1: Dry Atmospheric Absorption per Kilometer
The benefit of Oxygen absorption relative to frequency re-use is detailed in figure 2. Figure 2 illustrates the distance relationship between the 60GHz frequency reuse range, the green region, and the traditional range, the blue region. Oxygen absorption makes possible the same-frequency reuse within a very localized region of air space. Operation within the 60GHz millimeter wave spectrum enables very dense interference free deployment of same frequency radio terminals.

 

Figure 2: Frequency Reuse Source FCC Bulletin 70A
A 60GHz communications system must overcome the effects of oxygen absorption, 16dB/KM. In order to operate reliably at even short ranges, a very focused, narrow-beam antenna must also be employed to increase the level of signal available to the target receiver. This combination of oxygen absorption and narrow beam transmission enhances the security of the 60GHz radio link, minimizing the probability of unauthorized intercept.

Traditional wireless communications systems operating in the lower frequency ranges of 900MHz to 40GHz often interfere with each other when placed too closely together. This interference, due to the dispersion and uncontrolled propagation of RF energy through the atmosphere is minimized by FCC frequency coordination, licensing and through the implementation of interference avoidance techniques such as spread-spectrum modulation. FCC Licensing precludes dense deployment through the limited number of regional licenses granted and spread-spectrum techniques have proven only marginally effective, as the overall noise floor has risen. In the 60GHz region, the effects of oxygen absorption and the use of narrow beam antennae minimize the probability of interference between the radios. Theoretically, 100,000 systems operating at 60 GHz can be co-located in a ten square kilometer area without interference problems.

Weather conditions have an adverse effect on all RF transmissions, especially in the millimeter wave region where severe rainstorms can cause as much as a 20dB loss in signal strength for every kilometer of transmission. As the distance the radio transmission increases, the fade margin needed to compensate for weather effects increases proportionately. Since radios operating at 60GHz transmit only over short distances, the compensation for weather effects is not as great as for systems transmitting one kilometer and beyond.

At 60GHz, the extremely high atmospheric absorption level is due primarily to the molecular composition of the atmosphere. Figure 3 illustrates the atmospheric attenuation characteristics for wavelengths from 3 cm to 0.3 mm. For millimeter waves, the primary absorption molecules are H2O, O2, CO2 and O3. Since the presence of O2 is fairly consistent at ground level, its effect on 60GHz radio propagation is easily modeled for margin budgeting purposes. In addition, the high level of attenuation from oxygen absorption makes even the worst weather-related attenuation insignificant, especially on the short paths where 60GHz systems operate. Even extremely heavy rainfall, 25mm/hr (5dB/KM), will make only a very small percentage contribution to aggregate attenuation in the 60GHz oxygen absorption region.

 

Figure 3: Atmospheric Attenuation Characteristics for Wavelengths 3 cm. to 0.3 mm.
Currently, the Federal Communications Commission (FCC) has allocated the millimeter wave RF spectrum from 57.05 to 64GHz for unlicensed use under Part 15. All wireless equipment operating at 60GHz must obtain FCC Part 15 type certification. Once certified, the product can be deployed license-free throughout the United States. This unlicensed frequency spectrum allows the end-user to avoid the added cost of regional spectrum auctions held by the FCC or competition for the limited number of licensed bands.

Due to the unique characteristics of the 60GHz millimeter wave region and the raw bandwidth available, wireless communication at 60GHz offers a reliable “last mile” alternative to installing physical fiber. 60GHz communications systems can be used for a variety of applications, including metropolitan area networks, campus networks, network backbones, network branch links, temporary emergency restoration and local access.


Shigeaki (Shey) Hakusui is the president and founder of Harmonix Corporation, the manufacturer of the GigaLink 60GHz digital radio system used for high-speed, wireless communications. www.hxi.com

SOURCE :
https://www.rfglobalnet.com/doc/fixed-wireless-communications-at-60ghz-unique-0001

 

 


 

Millimeter-Wave interactions with the Human Body:

state of knowledge and recent advances

The biocompatibility of millimeter-wave devices and systems is an important issue due to the wide number of emerging body-centric wireless applications at millimeter waves. This review article provides the state of knowledge in this field and mainly focuses on recent results and advances related to the different aspects of millimeter-wave interactions with the human body. Electromagnetic, thermal, and biological aspects are considered and analyzed for exposures in the 30-100 GHz range with a particular emphasis on the 60-GHz band. Recently introduced dosimetric techniques and specific instrumentation for bioelectromagnetic laboratory studies are also presented. Finally, future trends are discussed.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/44B43B3E7CA335E5E1CD407BE2A1EA29/S1759078711000122a.pdf/millimeterwave_interactions_with_the_human_body_state_of_knowledge_and_recent_advances.pdf

“60-GHz broadband short-range communications for wireless personal area networks have been promoted by the WirelessHD Interest Group and WiGig alliance. The current target market applications are mainly restricted to indoor wireless high-definition multimedia devices [4]. Integrated 60-GHz front-ends are expected to be commercialized by 2014 on lap tops. Moreover, recent progress in miniaturiza- tion and low-cost devices has triggered research activities aiming at developing future millimeter-wave body area net- works (BAN).

 


 

Research on Wireless Radiation Exposure to the Immune System

Thursday, March 19, 2020

https://www.saferemr.com/2020/03/wireless-radiation-effects-on-immune-system.html

This compilation of research on the effects on the immune system from exposure to radio frequency radiation consists of excerpts from a research review published in a peer-reviewed journal in 2013 by Dr. Stanislaw Szmigielski and a list of references to studies published since 2000 that can be downloaded from http://bit.ly/saferemrImmuneSystem.

Reaction of the immune system to low-level RF/MW exposures

Szmigielski S. Reaction of the immune system to low-level RF/MW exposures. Science of the Total Environment. 2013 Jun 1; 454-455:393-400. doi: 10.1016/j.scitotenv.2013.03.034.

Abstract

Radiofrequency (RF) and microwave (MW) radiation have been used in the modern world for many years. The rapidly increasing use of cellular phones in recent years has seen increased interest in relation to the possible health effects of exposure to RF/MW radiation. In 2011 a group of international experts organized by the IARC (International Agency for Research on Cancer in Lyon) concluded that RF/MW radiations should be listed as a possible carcinogen (group 2B) for humans. The incomplete knowledge of RF/MW-related cancer risks has initiated searches for biological indicators sensitive enough to measure the “weak biological influence” of RF/MWs. One of the main candidates is the immune system, which is able to react in a measurable way to discrete environmental stimuli. 

In this review, the impacts of weak RF/MW fields, including cell phone radiation, on various immune functions, both in vitro [cell culture studies] and in vivo [live animal studies], are discussed. The bulk of available evidence clearly indicates that various shifts in the number and/or activity of immunocompetent cells [cells that can develop an immune response] are possible, however the results are inconsistent. For example, a number of lymphocyte [small white blood cells especially found in the lymphatic system] functions have been found to be enhanced and weakened within single experiments based on exposure to similar intensities of MW radiation. 

Certain premises exist which indicate that, in general, short-term exposure to weak MW radiation may temporarily stimulate certain humoral* or cellular immune functions, while prolonged irradiation inhibits the same functions.

https://www.ncbi.nlm.nih.gov/pubmed/23562692

Excerpts

“Recently, Jauchem (2008) reviewed the effects of RF/MW radiation on the immune system and concluded that although both positive and negative findings were reported in some studies, in a majority of instances no significant health effects were found. However, most studies had some methodological limitations. Some changes in immunoglobulin levels and in peripheral blood lymphocytes were reported in different studies of radar and radio/television-transmission workers (Moszczyński et al., 1999).”

Immunotropic effects of RF/MW exposure in in vitro studies

“In summary, it may be concluded that non-thermal intensities of RF/MW radiation may exert certain measurable effects and shifts in physiology of immunocompetent cells, however these effects appear to be weak, inconsistent and difficult to replicate. Among other stress reactions, induction of heat-shock proteins, altered reaction of lymphocytes to mitogens, weaken phagocytosis and/or bactericidal activity of macrophages were reported after in vitro exposure of isolated cells to arbitrarily chosen conditions of the exposure (frequency and modulation of the RF/MW radiation, power density, time and schedule of exposure, etc.). 

From studies performed in our laboratories (Dąbrowski et al., 2003; Stankiewicz et al., 2006, 2010) it may be concluded that in vitro effects of non-thermal RF/MWs cannot be revealed using basic tests for assessment of function of immunocompetent cells (including typical microculture of lymphocytes with mitogen stimulation) and finer techniques (e.g., immunogenic activity of monocytes (LM index), T-cell suppressive activity (SAT index) or release of cytokines in microcultures of PBMC) are required to study the effects of RF/MW exposures. Nevertheless, nothing can be concluded on thresholds of the above phenomena, their mechanisms or relevance to health risks. None of the above discussed studies provides data which can be directly or indirectly linked to cancer development (Table 1).”

Effects of in vivo RF/MW exposures on function of the immune system

“In summary, studies of immune reactions in animals exposed to MWs provide controversial results with some papers reporting no measurable response, while in others positive results were obtained. The available bulk of evidence from numerous experimental studies in vivo aimed to assess the effects of short-term and prolonged low-level MW exposure on function and status of the immune system clearly indicates that various shifts in number and/or activity of immunocompetent cells are possible. However, the results are incoherent; the same functions of lymphocytes are reported to be weaken[ed] or enhanced in single experiments with MW exposures at similar intensities and radiation parameters. There exist premises that in general, short-term exposure to weak MWs may temporarily stimulate certain humoral or cellular immune functions, while prolonged irradiation inhibits the same functions (Grigoriev et al., 2010). There exist papers which report changes in NK [natural killer] cell activity or TNF** release in MW-exposed animals, but clinical relevance or relation to carcinogenicity of these findings is doubtful.” 

https://www.sciencedirect.com/science/article/pii/S0048969713003276

[* Humoral immunity is mediated by macromolecules found in extracellular fluids such as secreted antibodies, complement proteins, and certain antimicrobial peptides.]

[** Tumor necrosis factor is a cell signaling protein involved in systemic inflammation.]

A new comprehensive review paper published in a peer-reviewed journal is needed to determine whether stronger inferences are warranted at this time.

A list of studies of the biologic and health effects on the immune system from exposure to radio frequency radiation published since 2000 can be downloaded at: http://bit.ly/saferemrImmuneSystem.

Dr. Szmigielski signed the Catania Resolution in 2002:

The Catania Resolution

According to several reports, a group of scientists issued a statement on EMF at a meeting in September.

They were attending the international conference “State of the Research on Electromagnetic Fields—Scientific and Legal Issues,” organized by ISPESL, the University of Vienna, and the City of Catania. ISPESL is a technical-scientific branch of the National Health Service that advises industry on protection of occupational health and well-being in the workplace. In Catania, Italy, on Sept. 13 and 14, 2002, they agreed to the following:

Epidemiological and in vivo and in vitro experimental evidence demonstrates the existence for electromagnetic field (EMF) induced effects, some of which can be adverse to health.

We take exception to arguments suggesting that weak (low intensity) EMF cannot interact with tissue.

There are plausible mechanistic explanations for EMF-induced effects which occur below present ICNIRP and IEEE guidelines and exposure recommendations by the European Union.

The weight of evidence calls for preventive strategies based on the precautionary principle. At times the precautionary principle may involve prudent avoidance and prudent use.

We are aware that there are gaps in knowledge on biological and physical effects, and health risks related to EMF, which require additional independent research.

The undersigned scientists agree to establish an international scientific commission to promote research for the protection of public health from EMF and to develop the scientific basis and strategies for assessment, prevention, management and communication of risk, based on the precautionary principle.   https://www.bems.org/node/824 

List of signatories: https://www.emrpolicy.org/faq/catania.pdf

 

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