Analysis and modeling of time-variant amplitude–frequency couplings of and between oscillations of EEG bursts

Low-frequency (0.5-2.5 Hz) and individually defined high-frequency (7-11 or 8-12 Hz; 11-15 or 14-18 Hz) oscillatory components of the electroencephalogram (EEG) burst activity derived from thiopental-induced burst-suppression patterns (BSP) were investigated in seven sedated patients (17-26 years old) with severe head injury. The predominant high-frequency burst oscillations (>7 Hz) were detected for each patient by means of time-variant amplitude spectrum analysis. Thereafter, the instantaneous envelope (IE) and the instantaneous frequency (IF) were computed for these low- and high-frequency bands to quantify amplitude-frequency dependencies (envelope-envelope, envelope-frequency, and frequency-frequency correlations). Time-variant phase-locking, phase synchronization, and quadratic phase couplings are associated with the observed amplitude-frequency characteristics. Additionally, these time-variant analyses were carried out for modeled burst patterns. Coupled Duffing oscillators were adapted to each EEG burst and by means of these models data-based burst simulations were generated. Results are: (1) strong envelope-envelope correlations (IE courses) can be demonstrated; (2) it can be shown that a rise of the IE is associated with an increase of the IF (only for the frequency bands 0.5-2.5 and 7-11 or 8-12 Hz); (3) the rise characteristics of all individually averaged envelope-frequency courses (IE-IF) are strongly correlated; (4) for the 7-11 or 8-12 Hz oscillation these associations are weaker and the variation between the time courses of the patients is higher; (5) for both frequency ranges a quantitative amplitude-frequency dependency can be shown because higher IE peak maxima are accompanied by stronger IF changes; (6) the time range of significant phase-locking within the 7-11 or 8-12 Hz frequency bands and of the strongest quadratic phase couplings (between 0.5-2.5 and 7-11 or 8-12 Hz) is between 0 and 1,000 ms; (7) all phase coupling characteristics of the modeled bursts accord well with the corresponding characteristics of the measured EEG burst data. All amplitude-frequency dependencies and phase locking/coupling properties described here are known from and can be discussed using coupled Duffing oscillators which are characterized by autoresonance properties.     

High frequency of triplicated α-globin loci and absence or low frequency of α thalassemia in Polynesian Samoans

Summary Most of the population in certain areas of Melanesia have one -globin gene deletion ( thal₂). It is thought that the high frequencies of thal₂ in this population is due to a selective advantage given by malaria infection to carriers of thal₂. We are interested in neighboring Polynesia which, although adjacent to Melanesia, has always been free of malaria due to the absence of the vector anopheles. We studied 60 Polynesian Samoans and 150 Malaysians by restriction endonuclease gene mapping using Eco RI, Bam HI, and Bgl II and hybridization to ³²P-labeled -globin gene probe. Seven among the 60 (11.7%) Samoans had triplicated -globin loci type 1, while none had thal₂. On digestion with Bgl II the third -globin gene was found in an additional 3.7kb fragment in all seven Samoans with triplicated -globin loci, while digestion with Bam HI produced an abnormal elongated 18.2 kb fragment carrying -globin genes in addition to the normal 14.5 kb fragment. None of the Polynesian Samoans had thal₂ or thal₁. Only two of the Malaysians had triplicated -globin loci.     

Imperfect Batesian mimicry—the effects of the frequency and the distastefulness of the model

Batesian mimicry is the resemblance between unpalatable models and palatable mimics. The widely accepted idea is that the frequency and the unprofitability of the model are crucial for the introduction of a Batesian mimic into the prey population. However, experimental evidence is limited and furthermore, previous studies have considered mainly perfect mimicry (automimicry). We investigated imperfect Batesian mimicry by varying the frequency of an aposematic model at two levels of distastefulness. The predator encountered prey in a random order, one prey item at a time. The prey were thus presented realistically in a sequential way. Great tits (Parus major) were used as predators. This experiment, with a novel signal, supports the idea that Batesian mimics gain most when the models outnumber them. The mortalities of the mimics as well as the models were significantly dependent on the frequency of the model. Both prey types survived better the fewer mimics there were confusing the predator. There were also indications that the degree of distastefulness of the model had an effect on the survival of the Batesian mimic: the models survived significantly better the more distasteful they were. The experiment supports the most classical predictions in the theories of the origin and maintenance of Batesian mimicry.     

Electromyogram of pericranial muscles in frequency bands β and γ comparing various cognitive and emotional states

Results of comparison of power of electromyogram (EMG) of six pericranial muscles in electroencephalographic frequency bands β₁, β₂ and γ are presented corresponding to performances of the tasks bound to inductions of affective experiences. The external induction was implemented by means of presentation of images and the internal induction by means of autobiographical memoirs revived. The tasks were focused on an induction of affective experiences with different emotional valences—positive, negative and neutral. The EMG was derived, registered and processed by means of computer electroencephalography techniques. Self-assessments of signs and intensities of experienced emotions were recorded as well. The study involved two groups of healthy subjects—students-actors (N = 39), and students of other specialties (N = 32). Statistically reliable, reproducible and diverse differences of mean EMG power of the pericranial muscles took place in comparisons of psychophysiological states with different valences of emotions, and certain differences in comparisons of states without expressed emotional differences, but differing in the direction of attention took place also. Therefore it is obviously necessary for an assessment of a degree of muscular contamination in records of high-frequency scalp electroencephalograms (EEG) to supplement psychophysiological EEG methods with EMG registration and statistical analysis and to do such registration for several facial muscles.     

The frequency and duration of Salmonella–macrophage adhesion events determines infection efficiency

Salmonella enterica causes a range of important diseases in humans and a in a variety of animal species. The ability of bacteria to adhere to, invade and survive within host cells plays an important role in the pathogenesis of Salmonella infections. In systemic salmonellosis, macrophages constitute a niche for the proliferation of bacteria within the host organism. Salmonella enterica serovar Typhimurium is flagellated and the frequency with which this bacterium collides with a cell is important for infection efficiency. We investigated how bacterial motility affects infection efficiency, using a combination of population-level macrophage infection experiments and direct imaging of single-cell infection events, comparing wild-type and motility mutants. Non-motile and aflagellate bacterial strains, in contrast to wild-type bacteria, collide less frequently with macrophages, are in contact with the cell for less time and infect less frequently. Run-biased Salmonella also collide less frequently with macrophages but maintain contact with macrophages for a longer period of time than wild-type strains and infect the cells more readily. Our results suggest that uptake of S. Typhimurium by macrophages is dependent upon the duration of contact time of the bacterium with the cell, in addition to the frequency with which the bacteria collide with the cell.     

Studies of the effects of liquid holding on viability and mutation frequency in N-methyl-N′-nitro-N-nitrosoguanidine-treated halophiles

The capacities ofHalobacterium cutirubrum and a moderate halophile NRC 41227 to survive and recover from treatment with N-methyl-N-nitro-N-nitrosoguanidine have been compared.Halobacterium cutirubrum is resistant to this chemical and its mutation frequency is only slightly affected, whereas NRC 41227 is highly sensitive and its mutation frequency is markedly increased. The chemically treated extreme halophile fully regains viability during liquid holding, in notable contrast to its known failure to recover from the effects of ultraviolet irradiation.     

Occurrence and frequency of precocious germination of somatic embryos is a genotpye — dependent phenomenon in wheat

Immature embryos of thirty-three genotypes of wheat were cultured on 2,4-D containing medium. Occurrence of precocious germination of the zygotic and somatic embryos simultaneously on the same medium was a striking feature observed during the course of work. The percentage of precocious germination was seen to vary extensively from 0–88% and 0–84% for zygotic and somatic embryos respectively. In the genotypes NI-5439 and NI-5643 which are characterized by a high tillering capacity, the phenomenon of precocious germination seems to take a different path from that observed in the other genotypes. This is evident since these two genotypes require total absence of hormone for shoot elongation although multiple shoot primordia are formed on auxin containing medium.Precocious germination also seems to be relevant to somatic embryogenesis and plantlet regeneration. This conclusion stems from the observation that a majority of the genotypes that show precocious germination of zygotic embryos have greater embryogenic potential. Consecutively, most of the genotypes that show precocious germination of somatic embryos exhibit a higher frequency and faster rate of plantlet regeneration.Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid - Ki Kinetin - thi - HCl Thiamine hydrochloride - E calli Embryogenic calli NCL Communication No. 4456     

High frequency of immature dendritic cells and altered in situ production of interleukin-4 and tumor necrosis factor-α in lung cancer

INTRODUCTION: Antigen-presenting cells, like dendritic cells (DCs) and macrophages, play a significant role in the induction of an immune response and an imbalance in the proportion of macrophages, immature and mature DCs within the tumor could affect significantly the immune response to cancer. DCs and macrophages can differentiate from monocytes, depending on the milieu, where cytokines, like interleukin (IL)-4 and granulocyte-macrophage colony-stimulating factor (GM-CSF) induce DC differentiation and tumor necrosis factor (TNF)-alpha induce DC maturation. Thus, the aim of this work was to analyze by immunohistochemistry the presence of DCs (S100+ or CD1a+), macrophages (CD68+), IL-4 and TNF-alpha within the microenvironment of primary lung carcinomas. RESULTS: Higher frequencies of both immature DCs and macrophages were detected in the tumor-affected lung, when compared to the non-affected lung. Also, TNF-alpha-positive cells were more frequent, while IL-4-positive cells were less frequent in neoplastic tissues. This decreased frequency of mature DCs within the tumor was further confirmed by the lower frequency of CD14-CD80+ cells in cell suspensions obtained from the same lung tissues analyzed by flow cytometry. CONCLUSION: These data are discussed and interpreted as the result of an environment that does not oppose monocyte differentiation into DCs, but that could impair DC maturation, thus affecting the induction of effective immune responses against the tumor.     

Submolecular-scale imaging of α-helices and C-terminal domains of tubulins by frequency modulation atomic force microscopy in liquid

In this study, we directly imaged subnanometer-scale structures of tubulins by performing frequency modulation atomic force microscopy (FM-AFM) in liquid. Individual α-helices at the surface of a tubulin protofilament were imaged as periodic corrugations with a spacing of 0.53 nm, which corresponds to the common pitch of an α-helix backbone (0.54 nm). The identification of individual α-helices allowed us to determine the orientation of the deposited tubulin protofilament. As a result, C-terminal domains of tubulins were identified as protrusions with a height of 0.4 nm from the surface of the tubulin. The imaging mechanism for the observed subnanometer-scale contrasts is discussed in relation to the possible structures of the C-terminal domains. Because the C-terminal domains are chemically modified to regulate the interactions between tubulins and other biomolecules (e.g., motor proteins and microtubule-associated proteins), detailed structural information on individual C-terminal domains is valuable for understanding such regulation mechanisms. The results obtained in this study demonstrate that FM-AFM is capable of visualizing the structural variation of tubulins with subnanometer resolution. This is an important first step toward using FM-AFM to analyze the functions of tubulins.     

Altered Ig hypermutation pattern and frequency in complementary mouse models of DNA polymerase ζ activity

To test the hypothesis that DNA polymerase ζ participates in Ig hypermutation, we generated two mouse models of Pol ζ function: a B cell-specific conditional knockout and a knock-in strain with a Pol ζ mutagenesis-enhancing mutation. Pol ζ-deficient B cells had a reduction in mutation frequency at Ig loci in the spleen and in Peyer's patches, whereas knock-in mice with a mutagenic Pol ζ displayed a marked increase in mutation frequency in Peyer's patches, revealing a pattern that was similar to mutations in yeast strains with a homologous mutation in the gene encoding the catalytic subunit of Pol ζ. Combined, these data are best explained by a direct role for DNA polymerase ζ in Ig hypermutation.     

Significant effects of precipitation frequency on soil respiration and its components—A global synthesis

Global warming intensifies the hydrological cycle, which results in changes in precipitation regime (frequency and amount), and will likely have significant impacts on soil respiration (R_s). Although the responses of R_s to changes in precipitation amount have been extensively studied, there is little consensus on how R_s will be affected by changes in precipitation frequency (PF) across the globe. Here, we synthesized the field observations from 296 published papers to quantify the effects of PF on R_s and its components using meta-analysis. Our results indicated that the effects of PF on R_s decreased with an increase in background mean annual precipitation. When the data were grouped by climate conditions, increased PF showed positive effects on R_s under the arid condition but not under the semi-humid or humid conditions, whereas decreased PF suppressed R_s across all the climate conditions. The positive effects of increased PF mainly resulted from the positive response of heterotrophic respiration under the arid condition while the negative effects of decreased PF were mainly attributed to the reductions in root biomass and respiration. Overall, our global synthesis provided for the first time a comprehensive analysis of the divergent effects of PF on R_s and its components across climate regions. This study also provided a framework for understanding and modeling responses of ecosystem carbon cycling to global precipitation change.     

Buzz-pollination in Neotropical bees:genus-dependent frequencies and lack of optimal frequency for pollen release

Over 50 genera of bees release pollen from flower anthers using thoracic vibrations,a phenomenon known as buzz-pollination.The efficiency of this process is directly affected by the mechanical properties of the buzzes,namely the duration,amplitude,and frequency.Nonetheless,although the effects of the former two properties are well described,the role of buzz frequency on pollen release remains unclear.Furthermore,nearly all of the existing studies describing vibrational properties of natural buzz-pollination are limited to bumblebees(Bombus)and carpenter bees(Xvlocopa)constraining our current understanding of this behavior and its evolution.Therefore,we attempted to minimize this shortcoming by testing whether flower anthers exhibit optimal frequency for pollen release and whether bees tune their buzzes to match these(optimal)frequencies.If true,certain frequencies will trigger more pollen release and lighter bees will reach buzz frequencies closer to this optimum to compensate their smaller buzz amplitudes.Two strategies were used to test these hypotheses:(i)the use of(artificial)vibrational playbacks in a broad range of buzz frequencies and amplitudes to assess pollen release by tomato plants(Solarium Ivcopersicum L.)and(ii)the recording of natural buzzes of Neotropical bees visiting tomato plants during pollination.The playback experiment indicates that although buzz frequency does affect pollen release,no optimal frequency exists for that.In addition,the recorded results of natural buzz-pollination reveal that buzz frequencies vary with bee genera and are not correlated with body size.Therefore,neither bees nor plants are tuned to optimal pollen release frequencies.Bee frequency of buzz-pollination is a likely consequence of the insect flight machinery adapted to reach higher accelerations,while flower plant response to buzz-pollination is the likely result of its pollen granular properties.     

Transforming growth factor-β1 downregulates beating frequency and remodeling of cultured rat adult cardiomyocytes

We have observed increased levels of transforming growth factor-₁ (TGF-₁) in human hibernating myocardium (HM). Impaired ventricular function in HM is known to be restored to normal following revascularization implying that myocardial structure in HM is to a certain degree preserved. We have therefore tested whether TGF-₁ can imitate features of HM by reducing the number and frequency of beating cells (chronotropism) and structural remodeling of cultured adult rat cardiomyocytes (ARC), thus saving substrate, energy, and oxygen. Parameters measured were cell size, protein synthesis, protein degradation, protein content, myofibrillogenesis, and chronotropism. ARC were stimulated for 6 days with sera from patients with coronary heart disease, as this period led to a maximum response of cells. An increase of 90% in cell surface area following such treatment was reduced to a 20% increase of the original size by TGF-₁. Concomitantly, the rate of protein synthesis dropped from 3.6-fold to 2.4-fold, and myofibrillogenesis was reduced. TGF-₁ downregulated both the number of contracting cells from 81% to 10% and the frequency from 52 to nine beats per minute. However, TGF-₁ treatment did not reduce the augmentation of protein content (1.28-fold versus 1.25-fold) indicating that protein degradation was also inhibited. Similar results were obtained with serum from healthy volunters. The effects of TGF-₁ were reversible. We conclude that TGF-₁ constrains protein turnover and beating activity in underperfused myocardium, thus mediating protection by adapting myocytes to shortages in blood supply.T. Kubin and M. Tomars contributed equally to this work.     

Species area-relationships and frequency — Floristical data analysis of 44 isolated woods in northwestern Germany

44 isolated ancient woods (9,3–8579 ha) in southeastern Lower Saxony (northwestern Germany), where the Tertiary hilly country meets the Pleistocene plain, were investigated. Complete lists of 273 vascular plant species showing a more or less strong preference for woodlands were made for each wood including all the species of the groups Querco-Fagetea, Trifolio-Geranietea, Galio-Calystegietalia (selection of species) and Epilobietea. The majority of character species of woods show either a low or a high frequency, whereas fewer ones have medium frequencies. Most of the rarer species have their main occurrence in the larger woods. The number of species of all of the four groups increases with area of the wood and the correlation between the number of species and the log of area is related by a highly significant linear regression. Comparison of a single wood with two smaller woods of the same total area reveals that the two smaller woods on average have the greater number of wood species. Considering this and the fact that the rarer species have their main occurrence in the larger woods, when discussing questions of nature conservation a simple comparison of number of species and area is problematical.     

Extent and high frequency of a short conversion between the human Aγ and Gγ fetal globin genes

Summary Southern blotting and DNA sequencing after polymerase chain reaction (PCR) amplification provide evidence for the frequent occurrence (in 7 out of 24 chromosomes) of a short conversion GA in the 3 end of the human fetal A globin gene. This short conversion is characterized by the presence, 3 nucleotides downstream from the termination codon of the A gene, of the TCAC sequence that is normally present at the equivalent position at the 3 end of the G gene; it is therefore identical to a conversion already described. Interestingly, we have found that this conversion is associated with the presence of theHindIII polymorphic restriction site in the A IVS2, occuppying an equivalent position in both the G and A genes. Our observations strengthen the hypothesis that the presence of the HindIII polymorphic restriction site in A IVS2 and the presence of the sequence TCAC at the 3 end of the A gene might be the result of a single conversion event.     

Drainage, soil fertility and fire frequency determine composition and structure of gumland heaths in northern New?Zealand

Vegetation and soils were sampled at remaining gumland heath ecosystems in northern New?Zealand to determine vegetation patterns, environmental controls and major threats to long-term persistence. Classification and ordination techniques identified six vegetation types reflecting differences in drainage, rainfall, altitude, nutrients, and time since fire. Two modal types reflected opposite ends of the main environmental spectra. Leptospermum scoparium (Myrtaceae) shrubland occurred on relatively better drained sites with lower rainfall, altitude, and soil nutrient levels, whereas Gleichenia dicarpa (Gleicheniaceae) fernland typically occurred on more poorly drained sites with higher rainfall, altitude, and nutrient levels. Another widespread vegetation type dominated by both Leptospermum scoparium and Gleichenia dicarpa occupied plots of intermediate drainage, rainfall, altitude and nutrients. The three remaining types were of limited distribution and reflected uncommon combinations of environmental conditions or recent fire. Low soil nutrients in gumlands (mean total N = 0.182%, total P = 0.004%, oven-dry weight) are reflected in low Leptospermum scoparium foliage nutrients (mean total N = 0.858%, total P = 0.034%, δ¹⁵N = δ6.06‰, oven-dry weight) and slow growth rates (mean annual height growth rate = 11.90 cm year^?1), as in heathlands in Australia and South Africa. Gumlands are threatened by non-native plant species invasion, especially Hakea sericea (Proteaceae); habitat destruction for agricultural, industrial, and suburban development; and nutrient enrichment from adjacent agricultural land. Currently, fire is much less common in gumlands (mean time since fire = 18.4 years) than during early European settlement and some communities are apparently reverting to forest. Research to investigate the use of fire as a management tool is recommended for long-term conservation of New?Zealand gumlands.     

Influences on mammals frequency of use of small bridges and culverts along the Qinghai–Tibet railway,China

Understanding the use of small bridges and culverts by wildlife to cross the Qinghai–Tibet railway will aid in the design of wildlife crossing structures for similar transportation infrastructure. From 2014 to 2016, 36 infrared cameras were placed inside 14 small bridges and 11 culverts along the Qinghai–Tibet railway to determine the structures’ effectiveness as wildlife passages. Thirteen species of mammals were found to use the small bridges and culverts to cross the railway. The crossing rates for all mammals were significantly higher for small bridges than for culverts. Tibetan antelope (Pantholops hodgsonii), Tibetan gazelle (Procapra picticaudata), kiang (Equus kiang), and wild yak (Bos mutus) preferred small bridges over culverts to cross the railway. In contrast, mountain weasel (Mustela altaica) and Asian badger (Meles leucurus) preferred culverts to cross the railway. The crossing rates of all mammals, particularly Tibetan gazelle and woolly hare, were positively influenced by structure width. Structure height had a positive influence on wild yak, but structure length had a negative influence on kiang. The distance to the highway had a positive influence on the crossing rates of all mammals, particularly wild yak and woolly hare. Human use of the structures had no influence on the crossings of most mammals except for common wolf. We suggest that road design schemes include large and open crossing structures to benefit most species with limitations on human activities near wildlife passages.     

Effects of “skeleton” photoperiods and high frequency light-dark cycles on the rhythm of cell division in synchronized cultures of Euglena

Summary Two further lines of evidence support the contention (Edmunds, 1966) that the cell cycle in autotrophically grown Euglena can be coupled to an endogenous, circadian biological clock under certain conditions. So-called skeleton photoperiods (LD: 3,6,3:12 and LD: 4,4,4:12) following a complete photoperiod regime entrain the cell division rhythm in the population to a precise 24 hr period, although the step-sizes of the successive fission bursts are always less than 2.00, indicating that not all cells divide in any one 24 hr interval. These findings imply that the continuous action of light is not required for synchronization and suggest that the putative oscillation underlying the rhythm can be phased by discrete light (or dark) pulses or signals.The effects of high frequency LD cycles whose periods were integral submultiples of 24 hr were also investigated. In most regimes (LD:1/4,1/2; LD:1/2,1; LD: 1,2; LD: 1,3; LD: 2,4; LD: 2,6; LD: 4,4) synchronous cell division iccurred in the culture with an average period of 26–27 hr, although only a fraction of the cells divided during any one burst. Similar results were obtained if (i) a synchronized culture was exposed to certain high frequency cycles whose periods were not integral submultiples of 24 hr (e.g., LD: 5,5 or LD: 8,8); (ii) an asynchronous culture (grown in LL) was subsequently exposed to a high frequency cycle; or (iii) a synchronized culture was subjected to a random LD cycle. The synchrony does not break down as long as the given LD regime is imposed and shows some indications of persistence in certain ensuing conditions of continuous illumination.A general formula was derived which predicts the time of division, t _D , for an individual cell: t _D =k+n, where k is the initial phase delay, n is an integer, and is the free-running period of the rhythm observed in the population. These results are interpreted as indicating that the high frequency cycles employed were unable to entrain the circadian oscillation(s) hypothesized to underly and gate cell division, with the result that the rhythm reverted to its free-running period. Exposure to such cycles, however, apparently either initiates a rhythm or synchronizes the phases of the individual oscillations in the populations of cells. The possible direct interaction between energy supply and the observed somewhat variable period lengths is discussed; also, the relevance of stochastic models for the decay of division synchrony in the absence of a recurrent synchronizing procedure is considered.Some of these results were initially reported at the 5th International Congress on Photobiology, Hanover, N.H., U.S.A., August 26–31, 1968.This work was supported by NSF research grants #GB-4140 and #GB-6892 to L. Edmunds.     

What determines the citation frequency of ecological papers?

Citation frequencies of scientific articles are increasingly used for academic evaluation in various disciplines, including ecology. However, the factors affecting citation rates have not been extensively studied. Here, we examine the association between the citation frequency of ecological articles and various characteristics of journals, articles and authors. Our analysis shows that the annual citation rates of ecological papers are affected by the direction of the study outcome with respect to the hypothesis tested (supportive versus unsupportive evidence), by article length, by the number of authors, and by their country and university of affiliation. These results cast doubt on the validity of using citation counts as an objective and unbiased tool for academic evaluation in ecology.     

No genotoxic effect in exfoliated bladder cells of rat under the exposure of 1800 and 2100 MHz radio frequency radiation

In this study, we aimed to investigate the effects of 1800 and 2100?MHz Radio Frequency (RF) radiation on the number of micronucleus (MN) in exfoliated bladder cells of rat which shows the genotoxic damage. Exposure period was 30?min/day, 6 days/week for a month and two months exposure periods. Thirty male wistar albino rats were used for five groups: Group I (n?=?6): 1800?MHz RF exposed animals for one month, Group II (n?=?6): 2100?MHz RF exposed animals for one month, Group III (n?=?6): 2100?MHz RF exposed for two months, Group IV (n?=?6): control group for one month, Group V (n?=?6): control group for two months. Rats of the control groups were housed in their home cages during the entire experimental period without subjecting to any experimental manipulation. 1800 and 2100?MHz RF exposures did not result in any significant MN frequencies in rat bladder cells with respect to the control groups (p?>?0.05). There was no statistically significant difference between 2100?MHz RF exposed groups, either. Further studies are needed to demonstrate if there is any genotoxic effect, micronucleus formation in other tissues of rats.