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1.
Bioelectromagnetics ; 45(5): 235-248, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38725116

RESUMO

With advances in technology, the emission of radiofrequency radiation (RFR) into the environment, particularly from mobile devices, has become a growing concern. Tyro 3, Axl, and Mer (TAM) receptors and their ligands are essential for spermatogenesis and testosterone production. RFR has been shown to induce testicular cell apoptosis by causing inflammation and disrupting homeostasis. This study aimed to investigate the role of TAM receptors and ligands in the maintenance of homeostasis and elimination of apoptotic cells in the testes (weeks), short-term sham exposure (sham/1 week), and middle-term sham exposure (sham/10 weeks). Testicular morphology was assessed using hematoxylin-eosin staining, while immunohistochemical staining was performed to assess expression levels of TAM receptors and ligands in the testes of all groups. The results showed that testicular morphology was normal in the control, sham/1 week, and sham/10 weeks groups. However, abnormal processes of spermatogenesis and seminiferous tubule morphology were observed in RFR exposure groups. Cleaved Caspase 3 immunoreactivity showed statistically significant difference in 1 and 10 weeks exposure groups compared to control group. Moreover, there was no significant difference in the immunoreactivity of Tyro 3, Axl, Mer, Gas 6, and Pros 1 between groups. Moreover, Tyro 3 expression in Sertoli cells was statistically significantly increased in RFR exposure groups compared to the control. Taken together, the results suggest that RFR exposure negatively affects TAM signalling, preventing the clearance of apoptotic cells, and this process may lead to infection and inflammation. As a result, rat testicular morphology and function may be impaired.


Assuntos
Ondas de Rádio , Receptores Proteína Tirosina Quinases , Testículo , Masculino , Animais , Testículo/metabolismo , Testículo/efeitos da radiação , Receptores Proteína Tirosina Quinases/metabolismo , Ondas de Rádio/efeitos adversos , Ratos , Ligantes , Apoptose/efeitos da radiação , Receptor Tirosina Quinase Axl , Ratos Wistar , Espermatogênese/efeitos da radiação , Caspase 3/metabolismo , Ratos Sprague-Dawley , Fatores de Tempo , Peptídeos e Proteínas de Sinalização Intercelular
2.
Electromagn Biol Med ; 42(3): 114-122, 2023 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-37270798

RESUMO

In recent years, the interactions of metal objects in human body with electromagnetic fields caused by devices working at fifth-generation (5G) frequencies have been studied by various researchers. A motivation behind this research was to evaluate the human body absorption of electromagnetic energy operating at sub-6 GHz 5G applications. According to this, the specific absorption rate (SAR) caused by new generation mobile phones was investigated in human heads wearing metal-framed spectacles and having metallic implants or earrings to analyse electromagnetic field exposure. A realistic human head model, including some metal objects, was numerically calculated, and analysed in terms of non-ionizing dosimetry. Simulations were carried out with the finite integration technique (FIT) based commercial software in the frequencies of 0.9, 1.8, 2.1, 2.45, 3.5 and 5 GHz, respectively. The maximum SAR of 14 × 10-5 W/kg for 10 g average tissue was calculated at 2.45 GHz frequency in the head model with earrings. The highest electric field strength of 0.52 V/m was observed at a 1.8 GHz frequency in the head model with all metal objects equipped. Results show that metal objects such as spectacles, dental implants and earrings can cause an increase in the SAR values for external biological tissues, and metal objects can behave as a kind of shield for deeper tissues. However, the obtained values are below the limits of international organisations.


Assuntos
Telefone Celular , Campos Eletromagnéticos , Humanos , Ondas de Rádio , Doses de Radiação , Eletricidade , Cabeça
3.
Reprod Sci ; 29(5): 1471-1485, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35015292

RESUMO

The use of electronic devices such as mobile phones has had a long stretch of rapid growth all over the world. Therefore, exposure to radio frequency radiation (RFR) has increased enormously. Here, we aimed to assess the balance between cell death and proliferation and also investigate the involvement of the JNK/p38 MAPK signaling pathway in the testis of rats exposed to 900 MHz RFR in acute and chronic periods (2 h/day, 5 days/week) for 1 or 10 weeks, respectively. The expression of proliferating cell nuclear antigen (PCNA), Bcl-xL, cleaved caspase-3, phosphorylated-JNK (p-JNK), and phosphorylated-p38 (p-p38) was analyzed in line with histopathology and TUNEL analysis in rat testis. There were no histopathological differences between sham and RFR groups in the acute and chronic groups. PCNA expression was not altered between groups in both periods. However, alterations for cleaved caspase-3 and Bcl-xL were observed depending on the exposure period. TUNEL analysis showed a significant increase in the RFR group in the acute period, whereas no difference in the chronic groups for the apoptotic index was reported. In addition, both p-p38 and p-JNK protein expressions increased significantly in RFR groups in both periods. Our study indicated that 900 MHz RFR might result in alterations during acute period exposure for several parameters, but this can be ameliorated in the chronic period in rat testis. Here, we also report the involvement of the p38/JNK-mediated MAPK pathway after exposure to 900 MHz RFR. Hence, this information might shed light in future studies toward detailed molecular mechanisms in male reproduction and infertility.


Assuntos
Ondas de Rádio , Testículo , Animais , Apoptose , Caspase 3 , Masculino , Antígeno Nuclear de Célula em Proliferação , Ondas de Rádio/efeitos adversos , Ratos , Proteínas Quinases p38 Ativadas por Mitógeno
4.
Int J Occup Saf Ergon ; 28(3): 1672-1682, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33870853

RESUMO

Non-ionizing dosimetry investigations of extremely low frequency (ELF) magnetic fields that are generated by underground power cables as well as the minimization of their health effects are significant topics handled by numerous researchers. In this study, ELF magnetic fields and current densities caused by three-phased underground transmission lines induced in the human model were examined utilizing both analytical and numerical methods. Analyses were carried out using a two-dimensional problem scenario for the comprehensive head and body model. The results of the finite element method (FEM)-based simulation studies and the analytical calculations are consistent with each other. Moreover, a magnetic field shielding method utilizing conductive material was presented in the study. The shielding technique performed with copper material was carried out to mitigate the magnetic field and possible dosimetry hazards in the ELF region. The proposed shield was a 4-mm reverse U-shaped copper material.


Assuntos
Cobre , Campos Magnéticos , Simulação por Computador , Campos Eletromagnéticos , Fenômenos Eletromagnéticos , Humanos
5.
Radiat Prot Dosimetry ; 194(1): 57-64, 2021 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-33993315

RESUMO

In this study, electric field and magnetic field strengths at 50 Hz are measured in a solar power plant located far from residential areas, and the measurement results near various sources of the electric and magnetic fields in the power plant are presented. Although the measured values for the electric field caused by the solar panel range between 0.07 and 1.33 V/m, the measured values for the magnetic field by the solar panel range between 0.037 and 0.19 µT. In front of the inverter, the measured value of the electric field reaches 0.7 V/m, whereas the measured value of the magnetic field reaches 2.2 µT. The results are presented and evaluated in light of the exposure limits to electromagnetic fields published by international organisations.


Assuntos
Campos Eletromagnéticos , Energia Solar , Eletricidade , Centrais Elétricas
6.
Perspect Psychiatr Care ; 57(4): 1862-1875, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33728706

RESUMO

PURPOSE: This study aimed to examine the patients' perceived social support, mental health, and marital satisfaction. DESIGN AND METHODS: Data were collected via Patient Information Form, Barthel Index of Activities of Daily Living, Marital Life Scale, Multidimensional Scale of Perceived Social Support, and General Health Questionnaire for 72 patients. FINDINGS: Multiple sclerosis (MS) patients had a moderate level of marital satisfaction. The perceived social support showed positive correlation with marital satisfaction and negative correlation with mental health disorders in MS. PRACTICE IMPLICATIONS: These results will facilitate the perception of mental problems, marital satisfaction, and social support in MS patients by the nurses.


Assuntos
Saúde Mental , Esclerose Múltipla , Atividades Cotidianas , Humanos , Satisfação do Paciente , Satisfação Pessoal , Apoio Social , Inquéritos e Questionários
7.
Electromagn Biol Med ; 40(2): 254-263, 2021 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-33622140

RESUMO

With the development of today's technology, the electromagnetic radiation spread by mobile phones and base stations is also rapidly increasing, and this causes serious concerns about the environment and human health. The Drosophila model organism is widely used in genetic toxicology studies because its genome is highly similar to the genes identified in human diseases. In this study, the genotoxic effects of radiofrequency electromagnetic radiation were evaluated by the wing Somatic Mutation and Recombination Test (SMART) in Drosophila melanogaster at 900 MHz, 1800 MHz, and 2100 MHz. The SMART method is based on the observation of genetic changes occurring in the trichomes of the Drosophila wings appearing as mutant clones under the microscope. Throughout the study, total clone parameters were evaluated by exposing the Drosophila larvae to electromagnetic fields for two, four, and six hours per day for two days. As a result of the study, it was observed that the number of mutant clones was statistically increased according to the negative control group in all applications except for the six-hour application at 1800 MHz.


Assuntos
Drosophila melanogaster , Radiação Eletromagnética , Animais , Dano ao DNA , Drosophila melanogaster/genética , Testes de Mutagenicidade , Mutação
8.
Electromagn Biol Med ; 40(1): 179-190, 2021 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-33259237

RESUMO

The present study evaluated whether short-term exposure to different doses of 2.1 GHz radiofrequency electromagnetic radiation (RF-EMR) has different effects on rats' behaviour and hippocampal levels of central cholinergic biomarkers. Animals were divided into three equal groups namely; group 1 was sham-exposed group, group 2-3 were exposed to 45 V/m and 65 V/m doses of 2.1 GHz frequency for 1 week respectively. Numerical dosimetry simulations were carried out. Object location and Y-maze were used as behavioural tasks. The protein and mRNA expression levels of AChE, ChAT, and VAChT, in the hippocampus were tested using Western Blotting and Real-Time PCR. The impairment performance of rats subjected to 65 V/m dose of 2.1 GHz RF-EMR in both object location and Y-maze tasks was observed. The hippocampal levels of AChE, ChAT, and VAChT, were significantly lower in rats exposed to 65 V/m dose of 2.1 GHz RF-EMR than others. The stronger effect of "65 V/m" dose on both rat's hippocampal-dependent behavioural performances and hippocampal levels of cholinergic biomarkers may be due to the stronger effect of "65 V/m" dose where rats' snouts were located at the nearest distance from the monopole antenna. Furthermore, the simulated SAR values were high for 65 V/m electric-field strengths. For the first time, we report the potential dose-dependent effects of short-term exposure to 2.1 GHz radiation on rat's behavioural performances as well as hippocampal levels of cholinergic biomarkers. Further studies are needed to understand the mechanisms by which RF-EMR influences the function of the central cholinergic system in the brain.


Assuntos
Radiação Eletromagnética , Hipocampo/fisiologia , Hipocampo/efeitos da radiação , Aprendizagem/efeitos da radiação , Animais , Biomarcadores/metabolismo , Relação Dose-Resposta à Radiação , Masculino , Ondas de Rádio , Ratos , Ratos Wistar
9.
Electromagn Biol Med ; 39(4): 374-386, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32865045

RESUMO

The aim of this study was to determine the effects of short and long-term RFR exposure on ABR by evaluating lipid peroxidation and antioxidant status in adult rats. Sixty male albino Wistar rats were randomly divided into four groups. S1:1 week sham, S10:10 weeks sham, E1:1 week RFR, E10:10 weeks RFR. Experimental group rats were exposed to RFR 2 h/day, 5 days/week during the test period. Sham rats were kept in the same conditions without RFR. After the experiment, ABRs were recorded from the mastoids of rats using tone burst acoustic stimuli. Biochemical investigations in rat brain and ultrastructural analysis in temporal cortex were performed. ABR wave I latency prolonged in E1-group and shortened in E10-group compared to their shams. TBARS level increased in E1-group, decreased in E10-group, on the contrary, SOD and CAT activities and GSH level decreased in E1-group, increased in E10-group compared to their sham groups. Edema was present in the neuron and astrocyte cytoplasms and astrocyte end-feet in both E1 and E10 groups. Our results suggest that 900 MHz RFR may have negative effects on the auditory system in acute exposure and no adverse effects in chronic exposure without weekends.


Assuntos
Córtex Auditivo/fisiologia , Córtex Auditivo/efeitos da radiação , Tronco Encefálico/fisiologia , Tronco Encefálico/efeitos da radiação , Ondas de Rádio/efeitos adversos , Animais , Masculino , Ratos , Ratos Wistar , Fatores de Tempo
10.
Int J Radiat Biol ; 94(9): 858-871, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29939075

RESUMO

PURPOSE: There is a growing interest in the usage of radiofrequency radiation (RF) as a noninvasive brain stimulation method. Previously reported data demonstrated that RF exposure caused a change in brain oscillations. Therefore, we aimed to investigate effects of RF on brain oscillation by measuring the auditory response of different brain regions in rats. MATERIALS AND METHODS: Rats were randomly divided into three groups (n = 12 per each group): Cage control (C), sham rats (Sh), and rats exposed to 2.1 GHz RF for 2 h/day for 7 days. At the end of the exposure, auditory evoked potentials (AEPs) were recorded at different locations in rats. Latencies and amplitudes of AEPs, evoked power, inter-trial phase synchronization, and auditory evoked gamma responses were obtained in response to an auditory stimulus. Furthermore, TBARS levels and 4-HNE, GFAP, iNOS, and nNOS expressions were evaluated in all groups. RESULTS: Peak-to-peak amplitudes of AEPs were significantly higher in the RF group compared with the Sh group. There is no significant difference in peak latencies of AEPs between groups. Beside, evoked power, inter-trial phase synchronization, and auditory evoked gamma responses were significantly higher in the RF group compared with the Sh group. In addition, the RF group had significantly lower TBARS and 4-HNE levels than the Sh group. There were no significant differences between groups for GFAP, nNOS, and iNOS levels, and between the C and RF groups for all parameters. CONCLUSIONS: Our present findings suggest that short-term RF treatment under chosen experimental conditions have statistically significant effect on neuronal networks of rats by probably reducing oxidative damage. However, this effect must be further studied for possible noninvasive brain stimulation.


Assuntos
Potenciais Evocados Auditivos/efeitos da radiação , Ondas de Rádio/efeitos adversos , Animais , Masculino , Ratos , Ratos Wistar , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismo , Fatores de Tempo
11.
Int J Radiat Biol ; 93(9): 980-989, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28565929

RESUMO

PURPOSE: To demonstrate the molecular effects of acute and chronic exposure to both 900 and 2100 MHz radiofrequency electromagnetic radiation (RF-EMR) on the hippocampal level/activity of some of the enzymes - including PKA, CaMKIIα, CREB, and p44/42 MAPK - from N-methyl-D-aspartate receptor (NMDAR)-related signaling pathways. MATERIALS AND METHODS: Rats were divided into the following groups: sham rats, and rats exposed to 900 and 2100 MHz RF-EMR for 2 h/day for acute (1 week) or chronic (10 weeks), respectively. Western blotting and activity measurement assays were used to assess the level/activity of the selected enzymes. RESULTS: The obtained results revealed that the hippocampal level/activity of selected enzymes was significantly higher in the chronic groups as compared to the acute groups at both 900 and 2100 MHz RF-EMR exposure. In addition, hippocampal level/activity of selected enzymes was significantly higher at 2100 MHz RF-EMR than 900 MHz RF-EMR in both acute and chronic groups. CONCLUSIONS: The present study provides experimental evidence that both exposure duration (1 week versus 10 weeks) and different carrier frequencies (900 vs. 2100 MHz) had different effects on the protein expression of hippocampus in Wistar rats, which might encourage further research on protection against RF-EMR exposure.


Assuntos
Campos Eletromagnéticos , Hipocampo/metabolismo , Hipocampo/efeitos da radiação , Micro-Ondas , Receptores de Glutamato/metabolismo , Transdução de Sinais/efeitos da radiação , Animais , Relação Dose-Resposta à Radiação , Masculino , Doses de Radiação , Exposição à Radiação , Ratos , Ratos Wistar , Transdução de Sinais/fisiologia , Fatores de Tempo , Irradiação Corporal Total/métodos
12.
Asia Pac J Oncol Nurs ; 4(1): 77-83, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28217734

RESUMO

OBJECTIVE: The main aim of this study was to investigate the factor structure and psychometric properties of the Brief Illness Perception Questionnaire (BIPQ) in Turkish cancer patients. METHODS: This methodological study involved 135 cancer patients. Statistical methods included confirmatory or exploratory factor analysis and Cronbach alpha coefficients for internal consistency. RESULTS: The values of fit indices are within the acceptable range. The alpha coefficients for emotional illness representations, cognitive illness representations, and total scale are 0.83, 0.80, and 0.85, respectively. CONCLUSIONS: The results confirm the two-factor structure of the Turkish BIPQ and demonstrate its reliability and validity.

13.
Electromagn Biol Med ; 35(3): 245-59, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27070942

RESUMO

In our previous study, the developmental effects of extremely low-frequency electric fields (ELF-EF) on visual and somatosensory evoked potentials in adult rats were studied. There is no study so far examining the effects of 50 Hz electric field (EF) on mismatch negativity (MMN) recordings after exposure of rats during development. Therefore, our present study aimed to investigate MMN and oxidative brain damage in rats exposed to EF (12 kV/m, 1 h/day). Rats were divided into four groups, namely control (C), prenatal (Pr), postnatal (Po), and prenatal+postnatal (PP). Pregnant rats of Pr and PP groups were exposed to EF during pregnancy. Following birth, rats of PP and Po groups were exposed to EF for three months. After exposure to EF, MMN was recorded by electrodes positioned stereotaxically to the surface of the dura, and then brain tissues were removed for histological and biochemical analyses. The MMN amplitude was higher to deviant tones than to standard tones. It was decreased in all experimental groups compared with the C group. 4-Hydroxy-2-nonenal (4-HNE) levels were significantly increased in the Po group with respect to the C group, whereas they were significantly decreased in the PP group compared with Pr and Po groups. Protein carbonyl levels were significantly decreased in the PP group compared with C, Pr, and Po groups. EF decreased MMN amplitudes were possibly induced by lipid peroxidation.


Assuntos
Eletricidade/efeitos adversos , Potenciais Evocados Auditivos , Estresse Oxidativo , Efeitos Tardios da Exposição Pré-Natal/metabolismo , Aldeídos/metabolismo , Animais , Apoptose , Encéfalo/metabolismo , Encéfalo/patologia , Encéfalo/fisiopatologia , Feminino , Masculino , Gravidez , Efeitos Tardios da Exposição Pré-Natal/patologia , Efeitos Tardios da Exposição Pré-Natal/fisiopatologia , Ratos , Ratos Wistar
14.
Brain Res ; 1635: 1-11, 2016 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-26776477

RESUMO

The purpose of the present study was to investigate the duration effects of 2100-MHz electromagnetic field (EMF) on visual evoked potentials (VEPs) and to assess lipid peroxidation (LPO), nitric oxide (NO) production and antioxidant status of EMF exposed rats. Rats were randomized to following groups: Sham rats (S1 and S10) and rats exposed to 2100-MHz EMF (E1 and E10) for 2h/day for 1 or 10 weeks, respectively. At the end of experimental periods, VEPs were recorded under anesthesia. Brain thiobarbituric acid reactive substances (TBARS) and 4-hydroxy-2-nonenal (4-HNE) levels were significantly decreased in the E1 whereas increased in the E10 compared with their control groups. While brain catalase (CAT), glutathione peroxidase (GSH-Px) activities and NO and glutathione (GSH) levels were significantly increased in the E1, reduction of superoxide dismutase (SOD) activity was detected in the same group compared with the S1. Conversely, decreased CAT, GSH-Px activities and NO levels were observed in the E10 compared with the S10. Latencies of all VEP components were shortened in the E1 compared with the S1, whereas latencies of all VEP components, except P1, were prolonged in the E10 compared with the S10. There was a positive correlation between all VEP latencies and brain TBARS and 4-HNE values. Consequently, it could be concluded that different effects of EMFs on VEPs depend on exposure duration. In addition, our results indicated that short-term EMF could provide protective effects, while long-term EMF could have an adverse effect on VEPs and oxidant/antioxidant status.


Assuntos
Antioxidantes/metabolismo , Encéfalo/fisiologia , Potenciais Evocados Visuais , Campos Magnéticos , Estresse Oxidativo , Animais , Encéfalo/metabolismo , Peroxidação de Lipídeos , Masculino , Óxido Nítrico/metabolismo , Ratos , Ratos Wistar
15.
Electromagn Biol Med ; 35(1): 65-74, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-25496054

RESUMO

The purpose of our study was to investigate the developmental effects of extremely low frequency electric fields (ELF-EFs) on visual evoked potentials (VEPs) and somatosensory-evoked potentials (SEPs) and to examine the relationship between lipid peroxidation and changes of these potentials. In this context, thiobarbituric acid reactive substances (TBARS) levels were determined as an indicator of lipid peroxidation. Wistar albino female rats were divided into four groups; Control (C), gestational (prenatal) exposure (Pr), gestational+ postnatal exposure (PP) and postnatal exposure (Po) groups. Pregnant rats of Pr and PP groups were exposed to 50 Hz electric field (EF) (12 kV/m; 1 h/day), while those of C and Po groups were placed in an inactive system during pregnancy. Following parturition, rats of PP and Po groups were exposed to ELF-EFs whereas rats of C and Pr groups were kept under the same experimental conditions without being exposed to any EF during 68 days. On postnatal day 90, rats were prepared for VEP and SEP recordings. The latencies of VEP components in all experimental groups were significantly prolonged versus C group. For SEPs, all components of PP group, P2, N2 components of Pr group and P1, P2, N2 components of Po group were delayed versus C group. As brain TBARS levels were significantly increased in Pr and Po groups, retina TBARS levels were significantly elevated in all experimental groups versus C group. In conclusion, alterations seen in evoked potentials, at least partly, could be explained by lipid peroxidation in the retina and brain.


Assuntos
Eletricidade , Potenciais Somatossensoriais Evocados , Potenciais Evocados Visuais , Animais , Feminino , Peroxidação de Lipídeos , Gravidez , Ratos , Ratos Wistar , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismo
16.
J Transcult Nurs ; 27(4): 413-9, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-25632948

RESUMO

This descriptive study was carried out to determine factors affecting health-promoting behaviors in nursing students. The sample consisted of 245 students. A questionnaire about factors affecting lifestyle behavior and the Health Promotion Lifestyle Profile Scale-II were used to collect data from 245 nursing students during the spring semester of the 2012-2013 academic year. A significant difference was found between students with and without diagnosed health problems in terms of their mean scores on the Health Promotion Lifestyle Profile Scale-II subscales of health responsibility, spiritual growth, and interpersonal relations, as well as their total mean scores (p < .05). The exercise, nutrition, spiritual growth, and stress management subscale scores of those students regularly going for health checks were determined to be significantly higher than those of the students who did not obtain regular health checks. Students' healthy lifestyle behaviors were generally found to be at the medium level. This study provides evidence of the need for interventions to help nurses in Turkey.


Assuntos
Comportamentos Relacionados com a Saúde , Estudantes de Enfermagem/psicologia , Adolescente , Bacharelado em Enfermagem/estatística & dados numéricos , Bacharelado em Enfermagem/tendências , Exercício Físico/psicologia , Feminino , Humanos , Masculino , Psicometria/instrumentação , Psicometria/métodos , Psicometria/estatística & dados numéricos , Espiritualidade , Estudantes de Enfermagem/estatística & dados numéricos , Inquéritos e Questionários , Turquia , Universidades/organização & administração , Adulto Jovem
17.
Radiat Prot Dosimetry ; 168(3): 365-73, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26116300

RESUMO

The potential harmful effect of electromagnetic fields on human health is an important issue that has been widely discussed in the scientific community. The investigation of temperature rise in human body following exposure to electromagnetic fields has been found impractical in many aspects. Therefore, fabrication of the tissue-equivalent liquids (TELs) is required. TELs have been widely employed in specific absorption rate calculations, dosimetry and hyperthermia researches. In this study, two separate head tissue-equivalent liquids (HELs) were prepared for 900 and 1800 MHz frequencies. The conductivity and relative permittivity of the HEL prepared for 900 MHz frequency were found to deviate from The Institute of Electrical and Electronics Engineers (IEEE) standards at the rates of 6.20 and 2.70 %, whereas the HEL prepared for 1800 MHz applications exhibited 1.83 and 3.22 % deviations from IEEE standards, respectively. This study provides a method for researchers to prepare their own HELs in a practical way.


Assuntos
Pesquisa Biomédica , Campos Eletromagnéticos/efeitos adversos , Febre , Cabeça/efeitos da radiação , Imagens de Fantasmas , Radiometria , Simulação por Computador , Humanos , Modelos Biológicos , Doses de Radiação
18.
Electromagn Biol Med ; 31(4): 436-48, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23045992

RESUMO

The aim of the study was to investigate the effects of extremely low-frequency electric field (ELF EF) on visual evoked potential (VEP), thiobarbituric acid reactive substances (TBARS), total antioxidant status (TAS), total oxidant status (TOS), and oxidant stress index (OSI). Thirty female Wistar rats, aged 3 months, were divided into three equal groups: Control (C), the group exposed to EF at 12 kV/m strength (E12), and the group exposed to EF at 18 kV/m strength (E18). Electric field was applied to the E12 and E18 groups for 14 days (1 h/day). Brain and retina TBARS, TOS, and OSI were significantly increased in the E12 and E18 groups with respect to the control group. Also, TBARS levels were significantly increased in the E18 group compared with the E12 group. Electric fields significantly decreased TAS levels in both brain and retina in E12 and E18 groups with respect to the control group. All VEP components were significantly prolonged in rats exposed to electric fields compared to control group. In addition, all latencies of VEP components were increased in the E18 group with respect to the E12 group. It is conceivable to suggest that EF-induced lipid peroxidation may play an important role in changes of VEP parameters.


Assuntos
Antioxidantes/metabolismo , Campos Eletromagnéticos , Potenciais Evocados Visuais/efeitos da radiação , Peroxidação de Lipídeos/efeitos da radiação , Animais , Encéfalo/metabolismo , Encéfalo/fisiologia , Encéfalo/efeitos da radiação , Feminino , Estresse Oxidativo/efeitos da radiação , Ratos , Ratos Wistar , Retina/metabolismo , Retina/efeitos da radiação , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismo
19.
Radiat Environ Biophys ; 50(3): 483-9, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21533655

RESUMO

A one-dimensional multi-layer model is presented to characterize skin temperature rises and burn processes resulting from skin exposure to microwaves. Temperature variations and damage function analyses in the skin tissue exposed to microwaves were predicted depending on blood perfusion rate, thermal conductivity, power density, and exposure time. Thermal wave model was applied and the bio-heat transfer equation was solved using the finite difference time domain method. The thermal wave model of bio-heat transfer predicts a lower temperature rise than a model that uses Pennes' equation. When approaching steady state, the solutions overlaps with that obtained using the Pennes' equation. The results obtained may help to analyze the consequences of short-time high-power MW exposures in biological tissues.


Assuntos
Queimaduras/etiologia , Micro-Ondas/efeitos adversos , Modelos Biológicos , Temperatura Cutânea , Pele/lesões , Pele/efeitos da radiação , Queimaduras/patologia , Humanos , Pele/citologia
20.
Burns ; 34(1): 45-9, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17624675

RESUMO

Thermal analyses of biological tissues exposed to microwaves were studied by using thermal wave model of bio-heat transfer (TWMBT). As a model, skin stratified as three layers with various thermal physical properties were simulated and thermal wave model of bio-heat transfer equations were solved by using finite difference method. Finally, the thermal variations were simulated in the cross section of the model. Comparative studies on the traditional Pennes' equations and thermal wave model of bio-heat transfer were performed and evaluated. Furthermore, temperature variations in the skin exposed to microwave were predicted depending on blood perfusion rate, thermal conductivity, frequency and power density of microwave, and exposure time. Thermal wave model of bio-heat transfer gives lower heat rise predictions than that of Pennes' equation, initially. When it approaches to steady state, it overlaps with the Pennes' equation.


Assuntos
Temperatura Alta , Micro-Ondas , Modelos Biológicos , Pele/efeitos da radiação , Epiderme/efeitos da radiação , Humanos , Fluxo Sanguíneo Regional/efeitos da radiação , Pele/irrigação sanguínea , Temperatura Cutânea/efeitos da radiação , Condutividade Térmica
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