Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 745
Filtrar
1.
PLoS One ; 15(1): e0222126, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31995555

RESUMO

Most existing cancer treatments involve high-cost chemotherapy and radiotherapy, with major side effects, prompting effort to develop alternative treatment modalities. It was reported that the combination of thermal-cycling hyperthermia (TC-HT) and phenolic compound exhibited a moderate cytotoxic effect against human pancreatic cancer PANC-1 cells. In this study, we investigate the efficacy of triple combination in PANC-1 cancer cells by adopting low-intensity pulsed electric field (LIPEF) to couple with TC-HT and CGA (chlorogenic acid). The study finds that this triple combination can significantly impede the proliferation of PANC-1 cells, with only about 20% viable cells left after 24h, whereas being non-toxic to normal cells. The synergistic activity against the PANC-1 cells was achieved by inducing G2/M phase arrest and apoptosis, which were associated with up-regulation of p53 and coupled with increased expression of downstream proteins p21 and Bax. Further mechanism investigations revealed that the cytotoxic activity could be related to mitochondrial apoptosis, characterized by the reduced level of Bcl-2, mitochondrial dysfunction, and sequential activation of caspase-9 and PARP. Also, we found that the triple treatment led to the increase of intracellular reactive oxygen species (ROS) production. Notably, the triple treatment-induced cytotoxic effects and the elevated expression of p53 and p21 proteins as well as the increased Bax/Bcl-2 ratio, all could be alleviated by the ROS scavenger, N-acetyl-cysteine (NAC). These findings indicate that the combination of CGA, TC-HT, and LIPEF may be a promising modality for cancer treatment, as it can induce p53-dependent cell cycle arrest and apoptosis through accumulation of ROS in PANC-1 cells.


Assuntos
Antineoplásicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Ácido Clorogênico/farmacologia , Neoplasias Pancreáticas/terapia , Apoptose/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Radiação Eletromagnética , Humanos , Hipertermia Induzida/métodos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Neoplasias Pancreáticas/patologia , Espécies Reativas de Oxigênio/metabolismo
2.
Bioelectromagnetics ; 41(1): 73-79, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31746011

RESUMO

Human exposure to electromagnetic fields produced by two wearable antennas operating in the 2.4 GHz frequency band was assessed by computational tools. Both antennas were designed to be attached to the skin, but they were intended for different applications. The first antenna was designed for off-body applications, i.e. to communicate with a device placed outside the body, while the second antenna model was optimized to communicate with a device located inside the body. The power absorption in human tissues was determined at several locations of adult male and female body models. The maximum specific absorption rate (SAR) value obtained with the off-body antenna was found on the torso of the woman model and was equal to 0.037 W/kg at 2.45 GHz. SAR levels increased significantly for the antenna transmitting inside the body. In this case, SAR values ranged between 0.23 and 0.45 W/kg at the same body location. The power absorbed in different body tissues and total power absorbed in the body were also calculated; the maximum total power absorbed was equal to 5.2 mW for an antenna input power equal to 10 mW. Bioelectromagnetics. 2020;41:73-79 © 2019 Wiley Periodicals, Inc.


Assuntos
Campos Eletromagnéticos/efeitos adversos , Desenho de Equipamento/instrumentação , Dispositivos Eletrônicos Vestíveis , Absorção de Radiação , Simulação por Computador , Radiação Eletromagnética , Feminino , Humanos , Masculino , Modelos Biológicos , Próteses e Implantes , Pele/metabolismo
3.
Sci Total Environ ; 698: 133860, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514029

RESUMO

The correlation between long-term exposure to SRF-EMR and the decline in male fertility is gradually receiving increasing attention from the medical society. While male reproductive organs are often exposed to SRF-EMR, little is currently known about the direct effects of long-term SRF-EMR exposure on the testes and its involvement in the suppression of male reproductive potential. The present study was designed to investigate this issue by using 4G SRF-EMR in rats. A unique exposure model using a 4G smartphone achieved localized exposure to the scrotum of the rats for 6 h each day (the smartphone was kept on active talk mode and received an external call for 1 min over 10 min intervals). Results showed that SRF-EMR exposure for 150 days decreased sperm quality and pup weight, accompanied by testicular injury. However, these adverse effects were not evident in rats exposed to SRF-EMR for 50 days or 100 days. Sequencing analysis and western blotting suggested Spock3 overexpression in the testes of rats exposed to SRF-EMR for 150 days. Inhibition of Spock3 overexpression improved sperm quality decline and alleviated testicular injury and BTB disorder in the exposed rats. Additionally, SRF-EMR exposure suppressed MMP2 activity, while increasing the activity of the MMP14-Spock3 complexes and decreasing MMP14-MMP2 complexes; these results were reversed by Spock3 inhibition. Thus, long-term exposure to 4G SRF-EMR diminished male fertility by directly disrupting the Spock3-MMP2-BTB axis in the testes of adult rats. To our knowledge, this is the first study to show direct toxicity of SRF-EMR on the testes emerging after long-term exposure.


Assuntos
Radiação Eletromagnética , Smartphone , Testículo/efeitos da radiação , Animais , Masculino , Ondas de Rádio , Ratos , Reprodução
4.
Ecotoxicol Environ Saf ; 188: 109786, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31698176

RESUMO

In the last few decades, tremendous increase in the use of wireless electronic gadgets, particularly the cell phones, has significantly enhanced the levels of electromagnetic field radiations (EMF-r) in the environment. Therefore, it is pertinent to study the effect of these radiations on biological systems including plants. We investigated comparative cytotoxic and DNA damaging effects of 900 and 1800 MHz EMF-r in Allium cepa (onion) root meristematic cells in terms of mitotic index (MI), chromosomal aberrations (CAs) and single cell gel electrophoresis (comet assay). Onion bulbs were subjected to 900 and 1800 MHz (at power densities 261 ±â€¯8.50 mW m-2 and 332 ±â€¯10.36 mW m-2, respectively) of EMF-r for 0.5 h, 1 h, 2 h, and 4 h. Root length declined by 13.2% and 12.3%, whereas root thickness was increased by 46.7% and 48.3% after 4 h exposure to 900 MHz and 1800 MHz, respectively. Cytogenetic studies exhibited clastogenic effect of EMF-r as depicted by increased CAs and MI. MI increased by 36% and 53% after 2 and 4 h exposure to 900 MHz EMF-r, whereas it increased by 41% and 67% in response to 1800 MHz EMF-r. Aberration index was increased by 41%-266% and 14%-257% during 0.5-4 h of exposure to 900 MHz and 1800 MHz, respectively, over the control. EMF-r exposure decreased % head DNA (DNAH) and increased % tail DNA (DNAT) and olive tail moment (OTM) at both 900 and 1800 EMF-r. In 4 h exposure treatments, head DNA (%) declined by 19% and 23% at 900 MHz and 1800 MHz, respectively. DNAT and OTM were increased by 2.3 and 3.7 fold upon exposure to 900 MHz EMF-r over that in the control, whereas 2.8 and 5.8 fold increase was observed in response to 1800 MHz EMF-r exposure for 4 h and the difference was statistically significant. The study concludes that EMF-r in the communication range (900 and 1800 MHz) adversely affect root meristems in plants and induce cytotoxic and DNA damage. EMF-r induced DNA damage was more pronounced at 1800 MHz than that at 900 MHz.


Assuntos
Aberrações Cromossômicas/efeitos da radiação , Dano ao DNA , Campos Eletromagnéticos/efeitos adversos , Radiação Eletromagnética , Meristema/efeitos da radiação , Cebolas/efeitos da radiação , Telefone Celular , Ensaio Cometa , Relação Dose-Resposta à Radiação , Meristema/citologia , Meristema/genética , Índice Mitótico , Cebolas/citologia , Cebolas/genética , Fatores de Tempo
5.
Environ Sci Pollut Res Int ; 27(3): 3413-3427, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31845252

RESUMO

Excess sludge was loaded by 2450 MHz electromagnetic wave in this study. The mechanism of electromagnetic wave loading on the releasing of bound water before sludge flocculation dewatering was investigated through observing the changes of extracellular polymeric substances (EPS) composition, surface charge, and particle size distribution. The results showed that the 8.55 g/g total suspended solids (TSS) of bound water was reduced with 160 J/mL electromagnetic wave, and the moisture content of sludge decreased by 3.02%. The EPS structure in the sludge floc matrix was destroyed and the LB-EPS content reduced. Simultaneously, infrared spectrum analysis indicated that bound water content was correlated both to the changes of hydrophilic and hydrophobic functional groups. Moreover, protein secondary structure analysis found that looser protein structure facilitated the exposure of internal hydrophobic groups and further promoted the sludge hydrophobic properties. Additionally, electromagnetic wave disintegrated colloidal stability through dipole motion. The zeta potential increased from - 25.57 to - 14.32 mV; the medium particle size (d0.5) decreased from 119.99 to 80.41 µm. More small molecules created in the supernatant were helpful to release bound water, which could further improve flocculation dewaterability of sludge with electromagnetic wave loading.


Assuntos
Esgotos , Eliminação de Resíduos Líquidos , Radiação Eletromagnética , Floculação , Tamanho da Partícula , Água
6.
PLoS One ; 14(12): e0226499, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31841536

RESUMO

Researchers are increasingly showing interest in the application of a Butler matrix for fifth-generation (5G) base station antennas. However, the design of the Butler matrix is challenging at millimeter wave because of the very small wavelength. The literature has reported issues of high insertion losses and incorrect output phases at the output ports of the Butler matrix, which affects the radiation characteristics. To overcome these issues, the circuit elements of the Butler matrix such as the crossover, the quadrature hybrid and the phase shifter must be designed using highly accurate dimensions. This paper presents a low-loss and compact single-layer 8 × 8 Butler matrix operating at 28 GHz. The optimum design of each circuit element is also demonstrated in detail. The designed Butler matrix was fabricated to validate the simulated results. The measured results showed return losses of less than -10 dB at 28 GHz. The proposed Butler matrix achieved a low insertion loss and a low phase error of ± 2 dB and ± 10°, respectively. In sum, this work obtained a good agreement between the simulated and measured results.


Assuntos
Radiação Eletromagnética , Desenho de Equipamento , Tecnologia sem Fio/instrumentação , Algoritmos , Simulação por Computador , Eletrodos , Desenho de Equipamento/economia , Software , Tecnologia sem Fio/economia
7.
J Drugs Dermatol ; 18(11): 1098-1102, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31738500

RESUMO

Objective: This study investigates the effects of high-intensity focused electromagnetic technology for induction of changes in abdominal muscles and abdominal subcutaneous fat. Methods: 22 male and female subjects (aged 34 to 64, mean BMI, 23.5kg/m2) underwent 8 treatments of the abdomen (2 per week) with a high-intensity focused electromagnetic field device. Subjects were scanned by computed tomography (CT) at baseline and 1 month after the eighth treatment. Sub-umbilical and epi-umbilical slices were used to measure the thickness of subcutaneous fat and abdominal muscles and the abdominal separation. In addition, standardized photographs, weight, and circumference measurements were collected. Results: While comparing baseline to follow-up measurements, CT data showed on average 17.5% (-3.1±1.9mm) reduction in subcutaneous fat and simultaneous 14.8% (+1.5±0.8mm) thickening of the rectus abdominis muscle. Subjects lost on average 3.9±3.1cm in the waist circumference. Most of the waist reduction effect was achieved after the fourth treatment. The width of abdominal separation decreased by 9.5% (-2.0±1.7mm). All results were highly significant (P<0.01) while weight change was insignificant (P<0.05). Digital photographs showed aesthetic improvement in most subjects. The treatments were painless and without adverse events. Conclusion: Results suggest that the investigated device is effective for abdominal body sculpting. This technology produced rectus muscle hypertrophy and a reduction in subcutaneous abdominal fat. Data suggests 4 treatments as the ideal protocol delivering 86% of the observed improvement. J Drugs Dermatol. 2019;18(11):1098-1102.


Assuntos
Terapia de Campo Magnético/instrumentação , Sobrepeso , Reto do Abdome/fisiologia , Gordura Subcutânea Abdominal/fisiologia , Adulto , Radiação Eletromagnética , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reto do Abdome/diagnóstico por imagem , Gordura Subcutânea Abdominal/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Resultado do Tratamento , Circunferência da Cintura
8.
Turk Neurosurg ; 29(6): 887-900, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31608966

RESUMO

AIM: To investigate the potential protective effects of melatonin on the chronic radiation emitted by third generation mobile phones on the brain. MATERIAL AND METHODS: A total of 24 male Wistar albino rats were divided into four equal groups. Throughout a 90-day experiment, no application was performed on the control group. The second group was exposed to 2100 MHz radiation for 30 minutes. Subcutaneous melatonin was injected into the third group. Subcutaneous melatonin injection was applied 40 minutes before radiation and then the fourth group was exposed to radiation for 30 minutes. At the end of the experiment, brain (cerebrum and cerebellum) tissues were taken from the subjects. Histochemical, immunohistochemical, ultrastructural and western blot analyses were applied. In addition to brain weight, Purkinje cells’ number, immunohistochemical H Score analyses and the results of the Western blot were examined statistically. RESULTS: With the application of radiation, neuronal edema, relatively-decreased numbers of neurons on hippocampal CA1 and CA3 regions, displacement of the Purkinje neurons and dark neurons findings were observed as a result of histochemical stainings. Radiation also activated the NMDA-receptor 2B/Calpain-1/Caspase-12 pathway, NMDA-receptor 2B and Calpain-1 with the findings being supported by western blot analyses. Pre-increased protein synthesis before apoptosis was identified by electron microscopy. CONCLUSION: Mobile phone radiation caused certain (ultra) structural changes on the brain and activated the NMDA-receptor 2B/ Calpain-1/Caspase-12 pathway; in addition, melatonin was found to be effective, but insufficient in demonstrating the protective effects.


Assuntos
Encéfalo/metabolismo , Calpaína/metabolismo , Caspase 12/metabolismo , Radiação Eletromagnética , Melatonina/farmacologia , Receptores de N-Metil-D-Aspartato/metabolismo , Animais , Antioxidantes/farmacologia , Apoptose/efeitos dos fármacos , Apoptose/efeitos da radiação , Encéfalo/efeitos dos fármacos , Encéfalo/efeitos da radiação , Calpaína/efeitos da radiação , Caspase 12/efeitos da radiação , Telefone Celular , Masculino , Ratos , Ratos Wistar , Receptores de N-Metil-D-Aspartato/efeitos da radiação , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/efeitos da radiação
9.
Artigo em Russo | MEDLINE | ID: mdl-31626159

RESUMO

BACKGROUND: Experimental studies have established that that low-intensity ultrahigh frequency (UHF) electromagnetic radiation (EMR) has a preventive effect under the action of radiation and other pathogenic factors, which manifests itself in the accelerated development of adaptation, in the predominance of anabolic reactions over catabolic ones, and in the strengthening of the body' structural reserves. At the same time, from the standpoint of studying the mechanisms of primary prevention, it is very important not only to identify the overall adaptation effect, but also to have an idea on the specific contribution of a physical factor used in the development of adaptation. AIM: To identify metabolic and ultrastructural adaption parameters under the action of low-intensity UHF EMR on healthy animals and to determine their stability (safety), by using a model of radiation exposure. MATERIAL AND METHODS: The experiments were carried on 42 mature male rats weighing 180-200g. All the rats were divided into 5 groups: 2 experimental groups of 8 animals each for the comparative study of the specific features of adaptation developed under the preliminary action of UHF EMR in healthy animals and under radiation; 2 control groups of 8 animals each, and one intact group of 10 animals. The lumbar region (the area of the projection of the adrenal glands) was exposed to UHF EMP for 2 min daily (a cycle of 10 sessions). The animals were once irradiated at 2 Gy 60Co gamma ray doses, by using an Agat-R apparatus. The investigation objects were the liver, adrenal glands, testes, and thymus. The investigators used biochemical assays (the levels of RNA and DNA, antioxidant activity, specific activity in the thymocyte genome), transmission electron microscopy of adrenocorticocytes in the adrenal bundle zone and Sertoli cells in the testis. Mitochondria (number, average and total area, number of cristae) were morphometrically analyzed. RESULTS: The metabolic and ultrastructural adaption changes induced by UHF EMR in healthy animals were ascertained to be able to withstand the pathogenic effect of radiation and at the same time showed both stability (safety) and certain variability (plasticity) in their reactions. In this case, there were increases in the synthesis of nucleic acids and in the activity of the antioxidant system; there was also mitochondrial structural stability that was more manifested in the adrenocorticocytes in the adrenal bundle zone. At the same time, there was also a decrease in the intensity (magnitude) of a number of adaptive indicators, although by and large they were significantly higher than the level of control (the effect of radiation). DISCUSSION: Thus, the effect of UHF EMR on healthy animals contributed to the development of adaptive rearrangements in the organs studied. The essence of these changes was mainly the enhancement of synthetic reactions, as indicated by a larger amount of RNA and DNA, the activation of cellular and intracellular regeneration with the increased processes of hyperplasia of the mitochondrial cristae and the higher levels of ribosomes and polysomes. In addition, it can be assumed that the use of UHF EMR has laid the physicochemical foundations of its antioxidant action as conformational rearrangements in the membranes, which increased their structural stability. The findings are indicative of the increased level of morphofunctional reserves in the studied cells and tissues due to their increased bioenergetic and plastic potential. CONCLUSION: This study has provided new data that expand our understanding of the features of the development of adaptive mechanisms and the formation of the body's structural and functional reserves under the primary prophylactic action of low-intensity UHF EMR, by using the model of radiation exposure.


Assuntos
Glândulas Suprarrenais/efeitos da radiação , Radiação Eletromagnética , Fígado/efeitos da radiação , Testículo/efeitos da radiação , Timo/efeitos da radiação , Animais , Masculino , Ratos
10.
Vestn Oftalmol ; 135(4): 41-49, 2019.
Artigo em Russo | MEDLINE | ID: mdl-31573556

RESUMO

PURPOSE: To investigate the clinical and morphological manifestations of ocular lesions resulting from acute exposure to microwave radiation (MR). MATERIAL AND METHODS: Twenty-four rabbits were included in the study and divided into four equal groups according to MR exposure time (15, 30, 45, 60 s). The right eyes of rabbits were exposed to MR of 3.97 GHz and energy density of 1.0 W/cm2. The sham control group consisted of six animals. The exposed (right) and the paired (left) eye were studied for clinical and morphological changes, content of proinflammatory cytokines IL-1ß, IL-6 and TNF-α in the anterior chamber and in the vitreous body after exposure to MR. RESULTS: Significant dose-dependent changes in the structure of the exposed eye were revealed. Formation of microwave cataract was noted at the MR exposure time of 15 seconds and more. Partial or complete de-epithelialization, stromal edema, endothelial damage and inflammatory infiltration in the cornea, effusion of protein and cellular reaction in the aqueous humor were detected after MR exposure of 30, 45 and 60 seconds. Cellular reaction in the vitreous body was observed after exposure time of 45 and 60 seconds. Exposure to MR for up to 1 minute did not lead to visible clinical or morphological (traditional methods of examination) damage of the retina and optic nerve within 24 hours. Significantly higher content of proinflammatory cytokines IL-1ß, IL-6 and TNF-α in the aqueous humor and vitreous body was revealed in animals exposed to MR for 45 and 60 seconds. CONCLUSION: Acute exposure of the organ of vision to electromagnetic microwave radiation can lead to adverse dose-dependent effects not only in the lens, but also in other structures of the eye.


Assuntos
Catarata , Cristalino , Animais , Humor Aquoso , Radiação Eletromagnética , Coelhos , Corpo Vítreo
11.
Bioelectromagnetics ; 40(8): 553-568, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31579965

RESUMO

Shallow penetration of millimeter waves (MMW) and non-uniform illumination in in vitro experiments result in a non-uniform distribution of the specific absorption rate (SAR). These SAR gradients trigger convective currents in liquids affecting transient and steady-state temperature distributions. We analyzed the effect of convection on temperature dynamics during MMW exposure in continuous-wave (CW) and pulsed-wave (PW) amplitude-modulated regimes using micro-thermocouples. Temperature rise kinetics are characterized by the occurrence of a temperature peak that shifts to shorter times as the SAR of the MMW exposure increases and precedes initiation of convection in bulk. Furthermore, we demonstrate that the liquid volume impacts convection. Increasing the volume results in earlier triggering of convection and in a greater cooling rate after the end of the exposure. In PW regimes, convection strongly depends on the pulse duration that affects the heat pulse amplitude and cooling rate. The latter results in a change of the average temperature in PW regime. Bioelectromagnetics. 2019;40:553-568. © 2019 Bioelectromagnetics Society.


Assuntos
Convecção , Temperatura Alta , Técnicas In Vitro , Radiação Eletromagnética , Humanos , Cinética , Ondas de Rádio , Temperatura
12.
Artigo em Inglês | MEDLINE | ID: mdl-31540320

RESUMO

The introduction of the fifth generation (5G) of wireless communication will increase the number of high-frequency-powered base stations and other devices. The question is if such higher frequencies (in this review, 6-100 GHz, millimeter waves, MMW) can have a health impact. This review analyzed 94 relevant publications performing in vivo or in vitro investigations. Each study was characterized for: study type (in vivo, in vitro), biological material (species, cell type, etc.), biological endpoint, exposure (frequency, exposure duration, power density), results, and certain quality criteria. Eighty percent of the in vivo studies showed responses to exposure, while 58% of the in vitro studies demonstrated effects. The responses affected all biological endpoints studied. There was no consistent relationship between power density, exposure duration, or frequency, and exposure effects. The available studies do not provide adequate and sufficient information for a meaningful safety assessment, or for the question about non-thermal effects. There is a need for research regarding local heat developments on small surfaces, e.g., skin or the eye, and on any environmental impact. Our quality analysis shows that for future studies to be useful for safety assessment, design and implementation need to be significantly improved.


Assuntos
Radiação Eletromagnética , Exposição Ambiental/efeitos adversos , Tecnologia sem Fio , Animais , Humanos
13.
Rocz Panstw Zakl Hig ; 70(3): 225-234, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31515981

RESUMO

In recent years, there has been a rapid increase in the number of electromagnetic radiation sources such as mobile phones and base stations of mobile telephony. This radiation has been classified by the International Agency for Research on Cancer as a possible human carcinogen (group 2B). For this reason, many studies have been carried out on the impact of mobile telephony on human health. The largest of the experiments were carried out on animals. Due to the divergent results of many studies, there was no clear answer on the possible carcinogenic effects of this type of radiation on health. Detection of cancer shortly after an exposure is the most difficult task in analyzing the results. Some of the studies require repetition and verification of the results. In the case of negative effects of electromagnetic fields on brain activity, sleep, heart rate, cognitive function and blood pressure, no consistent evidence has been obtained either. In view of the increasing popularity of mobile phones, their location at short distances from the body (mainly the head) and the development of mobile phone technologies (which entails an increase in the number of base stations), further research, especially among young people, is needed. The duration of human exposure to electromagnetic radiation is subject to an increase and only further research can provide an answer on the possible negative effects of mobile phones and base stations.


Assuntos
Telefone Celular , Campos Eletromagnéticos/efeitos adversos , Radiação Eletromagnética , Exposição Ambiental/efeitos adversos , Humanos , Polônia
14.
Bioelectromagnetics ; 40(7): 458-471, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31396987

RESUMO

The Virtual Population (ViP) phantoms have been used in many dosimetry studies, yet, to date, anatomical phantom uncertainty in radiofrequency (RF) research has largely been neglected. The objective of this study is to gain insight, for the first time, regarding the uncertainty in RF-induced fields during magnetic resonance imaging associated with tissue assignment and segmentation quality and consistency in anatomical phantoms by evaluating the differences between two generations of ViP phantoms, ViP1.x and ViP3.0. The RF-induced 10g-average electric (E-) fields, tangential E-fields distribution along active implantable medical devices (AIMD) routings, and estimated AIMD heating were compared for five phantoms that are part of both ViP1.x and ViP3.0. The results demonstrated that differences exceeded 3 dB (-29%, +41%) for local quantities and 1 dB (±12% for field, ±25% for power) for integrated and volume-averaged quantities (e.g., estimated AIMD-heating and 10 g-average E-fields), while the variation across different ViP phantoms of the same generation can exceed 10 dB (-68% and +217% for field, -90% and +900% for power). In conclusion, the anatomical phantom uncertainty associated with tissue assignment and segmentation quality/consistency is larger than previously assumed, i.e., 0.6 dB or ±15% (k = 1) for AIMD heating. Further, multiple phantoms based on different volunteers covering the target population are required for quantitative analysis of dosimetric endpoints, e.g., AIMD heating, which depend on patient anatomy. Phantoms with the highest fidelity in tissue assignment and segmentation should be used, as these ensure the lowest uncertainty and possible underestimation of exposure. To verify that the uncertainty decreases monotonically with improved phantom quality, the evaluation of differences between phantom generations should be repeated for any improvement in segmentation. Bioelectromagnetics. 2019;40:458-471. © 2019 Bioelectromagnetics Society.


Assuntos
Simulação por Computador , Metais/metabolismo , Modelos Anatômicos , Próteses e Implantes/efeitos adversos , Radiação Eletromagnética , Desenho de Equipamento , Segurança de Equipamentos , Humanos
15.
Bioelectromagnetics ; 40(7): 445-457, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31429952

RESUMO

This paper proposes a novel in vitro exposure system operating at millimeter-wave (mmWave) 28 GHz, one of the frequency bands under consideration for fifth generation (5G) communication. We employed the field uniformity concept along cross-sectional observation planes at shorter distances from the radiation antenna for better efficiency and a small-size system. A choke-ring antenna was designed for this purpose in consideration of a wider beamwidth (BW) and a symmetric far-field pattern across three principal planes. The permittivity of Dulbecco's modified Eagle's medium solution was measured to examine the specific absorption rate (SAR) of the skin cell layer inside a Petri dish model for a three-dimensional (3D) cell culture in vitro experiment. The best deployment of Petri dishes, taking into account a geometrical field symmetry, was proposed. Local SAR values within the cell layer among the Petri dishes were determined with different polarization angles. It was determined that this polarization effect should be considered when the actual exposure and deployment were conducted. We finally proposed an in vitro exposure system based on the field uniformity including downward exposure from an antenna for 3D cell culture experiments. A small-size chamber system was obtained, and the size was estimated using the planar near-field chamber design rule. Bioelectromagnetics. 2019;40:445-457. © 2019 Bioelectromagnetics Society.


Assuntos
Simulação por Computador , Campos Eletromagnéticos/efeitos adversos , Radiação Eletromagnética , Modelos Biológicos , Células Cultivadas , Meios de Cultura , Humanos , Doses de Radiação , Pele/citologia , Pele/metabolismo
16.
N Z Med J ; 132(1501): 64-72, 2019 08 30.
Artigo em Inglês | MEDLINE | ID: mdl-31465329

RESUMO

The issues of real or suspected health effects of radiofrequency fields, produced by cellphones, their base stations and many other devices, are complex and controversial. We believe that the most balanced and valid assessments of these issues are given by the extensive reports produced by reputable, multidisciplinary, expert groups. These use the principles of a comprehensive review to assess all available published literature and form their conclusions by consideration of the strength of the evidence from the available studies. This paper provides links to several of these reports, and shows how others can be accessed. These reports are large and complex, but freely available on websites. We summarise the most recent New Zealand report, which itself refers to and summarises many other reports. The scientific literature on these issues is enormous, particularly in animal and laboratory studies. There are some comprehensive reviews of these, demonstrating that the quality of the studies is very variable, and that, for example, results claiming to show increased genetic damage or other biological effects are much more common in studies of low quality, whereas higher-quality studies predominantly show no significant effects. Thus, while there are many reports which in isolation suggest health effects, there is no consistent evidence supporting important health effects caused by low intensities of radiofrequencies similar to those experienced by the general population. There are certainly many unanswered questions, and new studies need to be assessed carefully and replicated where possible. Thus, expert groups in several countries including New Zealand need to continue to regularly review new studies.


Assuntos
Radiação Eletromagnética/classificação , Exposição Ambiental , Saúde Pública/métodos , Exposição Ambiental/análise , Exposição Ambiental/prevenção & controle , Exposição Ambiental/normas , Humanos , Nova Zelândia
17.
Environ Sci Pollut Res Int ; 26(30): 30693-30710, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31463749

RESUMO

The primary objective of mobile phone technology is to achieve communication with any person at any place and time. In the modern era, it is impossible to ignore the usefulness of mobile phone technology in cases of emergency as many lives have been saved. However, the biological effects they may have on humans and other animals have been largely ignored and not been evaluated comprehensively. One of the reasons for this is the speedy uncontrollable growth of this technology which has surpassed our researching ability. Initiated with the first generation, the mobile telephony currently reaches to its fifth generation without being screened extensively for any biological effects that they may have on humans or on other animals. Mounting evidences suggest possible non-thermal biological effects of radiofrequency electromagnetic radiation (RF-EMR) on brain and behavior. Behavioral studies have particularly concentrated on the effects of RF-EMR on learning, memory, anxiety, and locomotion. The literature analysis on behavioral effects of RF-EMR demonstrates complex picture with conflicting observations. Nonetheless, numerous reports suggest a possible behavioral effect of RF-EMR. The scientific findings about this issue are presented in the current review. The possible neural and molecular mechanisms for the behavioral effects have been proposed in the light of available evidences from the literature.


Assuntos
Ansiedade/etiologia , Encéfalo/efeitos da radiação , Telefone Celular , Campos Eletromagnéticos/efeitos adversos , Memória/efeitos da radiação , Ondas de Rádio , Animais , Barreira Hematoencefálica/efeitos da radiação , Encéfalo/fisiopatologia , Radiação Eletromagnética , Humanos , Aprendizagem/efeitos da radiação , Locomoção/efeitos da radiação
18.
Electromagn Biol Med ; 38(4): 287-296, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31304806

RESUMO

The excessive exposure of patients with type 2 diabetes mellitus (T2DM) to electromagnetic radiation (EMR) from mobile phones or their base stations antenna may influence oxidative stress and development of diabetic complications. Here, we investigated the effects of exposing type 2 diabetic rats to EMR of 900 MHz emitted from GSM mobile phone antenna for 24 hours/day over a period of 28 days on hyperglycemia and hepatic oxidative stress. Male Sprague-Dawley rats were divided into 4 groups (12 rats/group): control rats, normal rats exposed to EMR, T2DM rats generated by nicotinamide/streptozotocin administration, and T2DM rats exposed to EMR. Our results showed that the exposure of T2DM rats to EMR nonsignificantly reduced the hyperglycemia and hyperinsulinemia compared to unexposed T2DM rats. The exposure of T2DM rats to EMR for 28 days increased the hepatic levels of MDA and Nrf-2 as well as the activities of superoxide dismutase (SOD) and catalase but decreased phosphorylated Akt-2 (pAkt-2) as compared to unexposed T2DM rats. Therefore, the decrease in the hepatic pAkt-2 in T2DM rats after the exposure to EMR may result in elevated level of hepatic MDA, even though the level of Nrf-2 and the activities of SOD and catalase were increased. Abbreviations: BGL: blood glucose level; EMR: electromagnetic radiation; GSM: global system for mobile communication; H2O2: hydrogen peroxide; LSD: least significance difference; MDA:malondialdehyde; Nrf-2: nuclear factor erythroid 2- related factor 2; PI3K: phosphoinositide-3-kinase; pAkt-2: phosphorylated Akt-2; Akt-2: protein kinase; ROS: reactive oxygen species; SEM: standard error of the mean; STZ: streptozotocin; SOD: superoxide dismutase ; O2-: superoxide radical; CT: threshold cycle; T2DM: type 2 diabetes mellitus.


Assuntos
Telefone Celular , Diabetes Mellitus Tipo 2/metabolismo , Radiação Eletromagnética , Fígado/metabolismo , Fígado/efeitos da radiação , Estresse Oxidativo/efeitos da radiação , Animais , Catalase/metabolismo , Fator de Transcrição de Proteínas de Ligação GA/metabolismo , Masculino , Malondialdeído/metabolismo , Fosforilação/efeitos da radiação , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos , Ratos Sprague-Dawley , Superóxido Dismutase/metabolismo , Fatores de Tempo
19.
BMJ Case Rep ; 12(7)2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31296627

RESUMO

We present a case of transient osteoporosis of the hip in a 38-year-old recreational trail runner. Shortly after a trail running competition, he developed acute hip pain, functional disability and an antalgic gait. Diagnosis was made with MRI showing bone marrow oedema, plain radiographs demonstrating osseous demineralisation and bone scintigraphy showing uniform radioactive uptake. Treatment included off-loading of the anatomical site for 6 months until symptom resolution, analgaesia, Vitamin D, bisphosphonates and pulsed electromagnetic field therapy. He recovered fully and returned to running activities 8 months after initial presentation. Transient osteoporosis of the hip is rare but benign, self-limiting condition; however, awareness and exact diagnosis are important as runners often present with hip pain and other more serious pathologies such as avascular necrosis or stress fractures need to be excluded.


Assuntos
Dor Aguda/complicações , Artralgia/complicações , Osteoporose/complicações , Osteoporose/diagnóstico por imagem , Corrida , Dor Aguda/terapia , Adulto , Analgesia , Artralgia/terapia , Conservadores da Densidade Óssea/uso terapêutico , Doenças da Medula Óssea/complicações , Doenças da Medula Óssea/diagnóstico por imagem , Doenças da Medula Óssea/terapia , Ácido Clodrônico/uso terapêutico , Edema/complicações , Edema/diagnóstico por imagem , Edema/terapia , Radiação Eletromagnética , Articulação do Quadril/diagnóstico por imagem , Humanos , Imagem por Ressonância Magnética , Masculino , Osteoporose/terapia , Radiografia , Cintilografia , Vitamina D/uso terapêutico
20.
Health Phys ; 117(6): 648-655, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31283546

RESUMO

Electronic devices have become ubiquitous in daily life, but they emit electromagnetic radiation, which may have negative health impacts at excessive levels. Little is known regarding the impact of radiation emissions on building occupants or strategies for reducing its intensity. This study applied a novel approach using system analysis to quantify radiation exposure in building spaces, examine building material responses to radiation propagation, and investigate risks to human health in the country of Qatar. Radiation intensity levels varied based on the location and type of building space. Different types of construction materials showed varied responses to electromagnetic field wave propagation. Drywall exhibited the best blocking effect, whereas glass and lumber walls exhibited poor blocking effects. The field strengths quantified in this study are less than the corresponding reference values specified by some jurisdictions, but they are still significantly higher than the safety levels defined in many other countries, which could result in significant health risks. The key strategies for improving indoor environmental quality include the use of shielding materials, spatial design, reduction of exposure time, increased exposure distance, and complete avoidance of exposure in sensitive areas.


Assuntos
Poluição do Ar em Ambientes Fechados/análise , Materiais de Construção/análise , Radiação Eletromagnética , Exposição Ambiental/análise , Monitoramento Ambiental/métodos , Medição de Risco/métodos , Humanos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA