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1.
Bioelectromagnetics ; 45(4): 193-199, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38444067

RESUMO

In Greece, 5G New Radio (NR) has started launching in the end of 2020, at the 3400-3800 MHz (FR1) frequency band. Focusing on 117 Base Stations (BSs) which were already equipped with 5G NR antennas, in situ broadband and frequency selective measurements have been conducted at minimum three points of interest, at adjacent rooftops (when accessible). The points have been selected according to the sweeping method and the electric field strength (E) value has been stored on the selected worst-case scenario point. Spectrum analysis was conducted in the FR1, for the allocated spectrum that corresponds to each mobile communication provider, in order to get preliminary results concerning the contribution of the 5G NR emissions in the general public exposure levels. The vast majority of the in situ measurements has been conducted in urban environments from the beginning of 2021 until the mid of 2022, since in Greece 5G NR services launching started from the big cities. Additionally, a 5G NR BS, installed in a suburban environment (in the city of Kalamata) is thoroughly investigated during its pilot and regular operation, based on broadband and frequency selective measurements data derived by the National Observatory of Electromagnetic Fields (NOEF) monitoring sensor network. In situ measurement data within the 5G NR frequency range are verified via the NOEF's output. The 5G NR contribution to the total E-field levels is assessed in time, from pilot to regular operation of the BS. In all cases, compliance with the reference levels for general public exposure is affirmed.


Assuntos
Campos Eletromagnéticos , Monitoramento de Radiação , Exposição Ambiental/análise , Grécia , Monitoramento de Radiação/métodos , Ondas de Rádio
2.
Am J Physiol Cell Physiol ; 326(3): C850-C865, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38145300

RESUMO

Wnt1-inducible signaling protein 1 (WISP1/CCN4) is a secreted matricellular protein that is implicated in lung and airway remodeling. The macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine that has been associated with chronic lung diseases. In this study, we aimed to investigate the WISP1 signaling pathway and its ability to induce the expression of MIF in primary cultures of fibroblasts from normal human lungs (HLFs). Our results showed that WISP1 significantly stimulated the expression of MIF in a concentration- and time-dependent fashion. In WISP1-induced expression of MIF, αvß5-integrin and chondroitin sulfate proteoglycans as well as Src tyrosine kinases, MAP kinases, phosphatidylinositol 3-kinase/Akt, PKC, and NF-κB were involved. WISP1-induced expression of MIF was attenuated in the presence of the Src kinase inhibitor PP2 or the MIF tautomerase activity inhibitor ISO-1. Moreover, WISP1 significantly increased the phosphorylation and activation of EGF receptor (EGFR) through transactivation by Src kinases. WISP1 also induced the expression of MIF receptor CD74 and coreceptor CD44, through which MIF exerts its effects on HLFs. In addition, it was found that MIF induced its own expression, as well as its receptors CD74/CD44, acting in an autocrine manner. Finally, WISP1-induced MIF promoted the expression of cyclooxygenase 2, prostaglandin E2, IL-6, and matrix metalloproteinase-2 demonstrating the regulatory role of WISP1-MIF axis in lung inflammation and remodeling involving mainly integrin αvß5, Src kinases, PKC, NF-κB, and EGFR. The specific signaling pathways involved in WISP1-induced expression of MIF may prove to be excellent candidates for novel targets to control inflammation in chronic lung diseases.NEW & NOTEWORTHY The present study demonstrates for the first time that Wnt1-inducible signaling protein 1 (WISP1) regulates migration inhibitory factor (MIF) expression and activity and identifies the main signaling pathways involved. The newly discovered WISP1-MIF axis may drive lung inflammation and could result in the design of novel targeted therapies in inflammatory lung diseases.


Assuntos
Pneumopatias , Fatores Inibidores da Migração de Macrófagos , Pneumonia , Humanos , Receptores ErbB , Pulmão , Fatores Inibidores da Migração de Macrófagos/genética , Metaloproteinase 2 da Matriz , NF-kappa B , Transdução de Sinais , Quinases da Família src
3.
Front Psychol ; 14: 1253352, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37868602

RESUMO

Previous research findings demonstrate that both savoring ability and the presence of high-quality friendships play a significant role in enhancing one's overall sense of wellbeing. However, these associations have not been thoroughly investigated within a diverse range of adults across their lifespans, nor have they been explored in the specific cultural context of Greece. Thus, the primary objective of this study was to delve into the relationships between close friendship quality, the utilization of savoring techniques, and wellbeing within the Greek cultural framework. The study involved 771 adults from Greece with an average age of 38.35 years, who completed the McGill Friendship Functions Questionnaire, the PERMA Profiler, and the Abridged Ways of Savoring Checklist. Results revealed that there exists a positive correlation between friendship quality and savoring strategies with overall wellbeing. Moreover, the study identified a significant association wherein a greater employment of savoring strategies was linked to higher levels of friendship quality. While this study contributes valuable insights, it also has limitations that warrant acknowledgment. Furthermore, suggestions for potential future research directions are proposed, and the implications of these findings are discussed in relation to interventions aimed at enhancing both friendships and the practice of savoring across various contexts.

4.
Respirology ; 28(8): 767-774, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37311657

RESUMO

BACKGROUND AND OBJECTIVE: Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are associated with worsening health outcomes and effective treatment of each episode is essential. In this study, we aimed to investigate if plasma levels of heparan sulphate (HS) are associated with the aetiology of AECOPD. METHODS: COPD patients (N = 1189), GOLD grade II-IV, from a discovery cohort (N = 638) and from a validation cohort (N = 551), were included in the study. HS and heparanase (HSPE-1) were measured longitudinally in plasma at stable state, at AECOPD and at 4 weeks follow-up. RESULTS: Plasma HS was higher in patients with COPD as compared with non-COPD controls and was significantly increased at AECOPD as compared to stable state (p < 0.001) in the discovery and in the validation cohorts. Four distinct exacerbation groups were classified based on aetiology (no-infection/bacterial-infection/viral-infection/bacterial and viral coinfection) in the validation cohort. The fold-increase of HS from stable state to AECOPD was associated with the aetiology of exacerbation and was higher in cases with bacterial and viral coinfections. HSPE-1 was also significantly increased at AECOPD, however, there was no association of HSPE-1 levels with the aetiology of these events. The probability of having an infection at AECOPD was raised as HS levels increased from stable state to AECOPD. This probability was higher for bacterial infections than viral infections. CONCLUSION: The results of our study indicate that circulating levels of HS are increased at AECOPD and this increase may be associated with the aetiology of these events.


Assuntos
Doença Pulmonar Obstrutiva Crônica , Viroses , Humanos , Sulfatos , Progressão da Doença
5.
Appl Immunohistochem Mol Morphol ; 31(4): 239-244, 2023 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-36877184

RESUMO

The involvement of polycystin-2 (PC2) in cell survival pathways raises questions about its role in carcinogenesis. Aberrant expression of PC2 has been associated with malignancy in various tumors. No evidence exists referring to PC2 expression in meningiomas. The aim of this study was to investigate the expression levels of PC2 in meningiomas and compare them with normal brain samples including leptomeninges. PC2 immunohistochemical expression was quantitatively analyzed in archival tissue from 60 patients with benign (WHO grade 1) and 22 patients with high-grade (21: WHO grade 2 and 1: grade 3) meningiomas. Specifically, the labeling index [the percentage of positive (labeled) cells out of the total number of tumor cells counted] was determined. PC2 mRNA levels were evaluated by quantitative real-time polymerase chain reaction. PC2 immunostaining was not detected in the leptomeninges. Gene expression analysis revealed increased levels of PC2 in WHO grade 1 ( P = 0.008) and WHO grade 2 ( P = 0.0007) meningiomas compared with that of normal brains. PC2 expression was significantly associated with an ascending grade of malignancy by both immunohistochemistry and quantitative real-time polymerase chain reaction ( P < 0.05). Recurrent meningiomas displayed higher levels of PC2 compared with primary meningiomas ( P = 0.008). Although no significant association of PC2 with the overall survival of the patients was found ( P > 0.05), it was noticed that the patients with WHO grade 2 meningiomas with low expression of PC2 survived longer compared with the patients with WHO grade 1 meningioma with high expression of PC2 (mean survival 49.5 and 28 months, respectively). The above results indicate a possible association of PC2 with malignancy in meningiomas. However, the mechanisms underlying PC2 implication in meningioma pathogenesis should be further elucidated.


Assuntos
Neoplasias Meníngeas , Meningioma , Humanos , Meningioma/metabolismo , Neoplasias Meníngeas/metabolismo , Canais de Cátion TRPP/genética , Recidiva Local de Neoplasia/metabolismo , Perfilação da Expressão Gênica
6.
Int J Mol Sci ; 24(4)2023 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-36835197

RESUMO

Matrix metalloproteinases (MMPs) are proteolytic enzymes that degrade proteins of the extracellular matrix and the basement membrane. Thus, these enzymes regulate airway remodeling, which is a major pathological feature of chronic obstructive pulmonary disease (COPD). Furthermore, proteolytic destruction in the lungs may lead to loss of elastin and the development of emphysema, which is associated with poor lung function in COPD patients. In this literature review, we describe and appraise evidence from the recent literature regarding the role of different MMPs in COPD, as well as how their activity is regulated by specific tissue inhibitors. Considering the importance of MMPs in COPD pathogenesis, we also discuss MMPs as potential targets for therapeutic intervention in COPD and present evidence from recent clinical trials in this regard.


Assuntos
Metaloproteinases da Matriz , Doença Pulmonar Obstrutiva Crônica , Enfisema Pulmonar , Humanos , Enfisema , Matriz Extracelular/metabolismo , Pulmão/metabolismo , Metaloproteinases da Matriz/metabolismo , Doença Pulmonar Obstrutiva Crônica/metabolismo , Enfisema Pulmonar/metabolismo
7.
Neuropsychiatr Dis Treat ; 18: 2379-2389, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36268266

RESUMO

Telepractice or teletherapy is defined as the means of service delivery via technology-based platforms that allow long-distance interventions across populations, age spans, and geographical locations. Specifically, telepractice capitalizes on communication technologies such as online modules, videoconferencing, and computerized software programs, in servicing populations with communication challenges. Notably, telepractice has emerged as a potentially effective, low-cost, and promising means of conducting and completing online assessment, diagnosis, and intervention sessions for individuals with autism spectrum disorders (ASD). Moreover, telepractice allows the inclusion of parents, caregivers, and educators as potential facilitators in supporting treatment delivery in populations with ASD. This thematic review article aims to highlight and acquaint practitioners and other stakeholders with relatively recent information regarding the advantages and disadvantages of the telepractice service delivery model in ASD. Furthermore, the emergence of the COVID-19 pandemic has impacted service delivery in the field of Health Sciences including speech and language pathology (SLP). Consequently, the need to avoid face-to-face therapy sessions, recommended to SLPs as to all health practitioners, resulted in the call for adaptation and adjustment of service telepractice. This paper attempts to answer this call by suggesting supplementing traditional diagnostic and therapy resources with training modules consisting of online materials and use of animated and specially designed programs in SLP intervention with individuals with ASD. Lastly, the paper includes a discussion of research findings in the field, a conclusion, and a take-home message.

9.
Folia Phoniatr Logop ; 73(3): 185-194, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33341816

RESUMO

OBJECTIVES: The aims of this study were: (1) to investigate the effect of colorful semantics (CS) on the morphosyntactic and semantic development of Cypriot-Greek (CG)-speaking children with autism spectrum disorder (ASD) to obtain a better understanding of its role in an augmentative communication (AC) intervention program; (2) to address the paucity of intervention tools geared for CG-speaking children with ASD. PARTICIPANTS AND METHODS: The study included 24 boys and 16 girls with ASD, all preschool-aged 4-6 years. All were verbal but with limited production and minimal mean length of utterance. The study followed a randomized control trial design with equally sized experimental and control groups. The experimental group followed a therapeutic program using the AC with a CS protocol, while the control group's AC intervention did not include the CS protocol. RESULTS: The use of CS significantly improved the children's semantic and morphosyntactic development. CONCLUSIONS: The intervention results illustrate the effectiveness of CS in this study; however, generalizability of effectiveness to other similar CG-speaking children with ASD requires further evidence.


Assuntos
Transtorno do Espectro Autista , Semântica , Transtorno do Espectro Autista/complicações , Transtorno do Espectro Autista/terapia , Criança , Pré-Escolar , Feminino , Grécia , Humanos , Masculino
10.
Front Oncol ; 11: 826865, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35111687

RESUMO

Breast cancer exists in multiple subtypes some of which still lack a targeted and effective therapy. Cold atmospheric plasma (CAP) has been proposed as an emerging anti-cancer treatment modality. In this study, we investigated the effects of direct and indirect CAP treatment driven by the advantageous nanosecond pulsed discharge on breast cancer cells of different malignant phenotypes and estrogen receptor (ER) status, a major factor in the prognosis and therapeutic management of breast cancer. The main CAP reactive species in liquid (i.e. H2O2, NO 2 - /NO 3 - ) and gas phase were determined as a function of plasma operational parameters (i.e. treatment time, pulse voltage and frequency), while pre-treatment with the ROS scavenger NAC revealed the impact of ROS in the treatment. CAP treatment induced intense phenotypic changes and apoptosis in both ER+ and ER- cells, which is associated with the mitochondrial pathway as evidenced by the increased Bax/Bcl-2 ratio and cleavage of PARP-1. Interestingly, CAP significantly reduced CD44 protein expression (a major cancer stem cell marker and matrix receptor), while differentially affected the expression of proteases and inflammatory mediators. Collectively, the findings of the present study suggest that CAP suppresses breast cancer cell growth and regulates several effectors of the tumor microenvironment and thus it could represent an efficient therapeutic approach for distinct breast cancer subtypes.

11.
Bioelectromagnetics ; 40(8): 602-605, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31541484

RESUMO

From 2013 to 2018, in-situ measurements of radiofrequency (RF) electromagnetic fields (EMF) and extremely low-frequency (ELF) electric and magnetic fields in 317 existing and under-construction children's playground facilities, in 16 municipalities all over Greece, were carried out by the Greek Atomic Energy Commission (EEAE). These measurements were conducted following legislative framework established in 2009, which requires that compliance with the established exposure limits for EMFs should be verified in playground areas. The results are presented by the value of the electric field (E) and exposure ratio (Λ) for the RF EMF, as well as the value of the electric field (E) and magnetic flux density (B) for the ELF electric and magnetic fields. Statistical analysis tools were applied on measurement data and conclusions have been made, taking into consideration: (i) environment type (urban/suburban), and (ii) vicinity to any transmitting installations. Measurement results correspond to the typical EMF background levels for each environment type. Concerning the environment type, RF EMF, and ELF electric/magnetic field measurements reveal no differentiation between urban and suburban environments. Bioelectromagnetics. 2019;40:602-605. © 2019 Bioelectromagnetics Society.


Assuntos
Campos Eletromagnéticos , Ondas de Rádio , Criança , Campos Eletromagnéticos/efeitos adversos , Grécia , Humanos , Exposição à Radiação , Monitoramento de Radiação , Ondas de Rádio/efeitos adversos
12.
BMC Ophthalmol ; 18(1): 328, 2018 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-30563490

RESUMO

BACKGROUND: Pterygium is a condition characterized by epithelial overgrowth of the cornea, inflammatory cell infiltration and an abnormal extracellular matrix accumulation. Chronic UV exposure is considered as a pathogenic factor of this disease. Proteasome is an intracellular multi-subunit protease complex that degrades intracellular proteins. Among proteasome subunits the ß5 (PSMB5), bearing chymotrypsin-like activity. It is considered as the main proteasome subunit and its expression is mediated by Nrf2-ARE pathway in many cell types. This study investigates the expression of PSMB5 in pterygium and the effect of UVB irradiation on its expression and activity in pterygium fibroblasts. METHODS: Normal conjunctival and pterygium specimens were obtained from the bulbar conjunctiva of patients undergoing cataract surgery and from patients with pterygium undergoing surgical removal of primary tissue, respectively. Fibroblasts were isolated upon treatment of specimens with clostridium collagenase. The expression of PSMB5 and Nrf2 in tissues and cells was ascertained by RT-PCR analysis and western blotting. Cell survival was measured by the MTT method and the proteasome chymotrypsin-like activity was determined by fluorometry. RESULTS: RT-PCR analysis showed that the expression of PSMB5 was significantly lower in pterygium than in normal conjunctiva. The expression of PSMB5 was mediated by the Nrf2/ARE pathway as indicated by using the Nrf2 activator Oltipraz. The expression of PSMB5 and Nrf2 by pterygium fibroblasts was suppressed in a dose dependent manner following UVB radiation of 0-50 mJ/cm2 doses. The expression of PSMB5, but not of Nrf2, remained at almost the control levels, when UVB exposure was performed after pre-incubation of cells with the src kinases inhibitor PP2. UVB irradiation had very low deleterious effect on fibroblasts survival, while it did not affect the proteasome chymotrypsin-like activity. CONCLUSION: In pterygium fibroblasts, UVB exposure leads to down-regulation of Nrf2/ARE-mediated PSMB5 gene expression, in which src kinases may be implicated. This effect may be partially responsible for the lower expression of PSMB5 detected in pterygium as compared to normal conjunctiva.


Assuntos
Fibroblastos/metabolismo , Fibroblastos/efeitos da radiação , Complexo de Endopeptidases do Proteassoma/metabolismo , Pterígio/metabolismo , Raios Ultravioleta/efeitos adversos , Idoso , Idoso de 80 Anos ou mais , Sobrevivência Celular , Células Cultivadas , Túnica Conjuntiva/metabolismo , Regulação para Baixo , Feminino , Regulação da Expressão Gênica/efeitos da radiação , Humanos , Masculino , Pessoa de Meia-Idade , Fator 2 Relacionado a NF-E2/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa
13.
Med Biol Eng Comput ; 56(5): 809-816, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29027087

RESUMO

Microwave radiometry is a passive technique used to measure in-depth temperature distributions inside the human body, potentially useful in clinical applications. Experimental data imply that it may provide the capability of detecting in-depth local variations of temperature and/or conductivity of excitable tissues at microwave frequencies. Specifically, microwave radiometry may allow the real-time monitoring of brain temperature and/or conductivity changes, associated with local brain activation. In this paper, recent results of our ongoing research regarding the capabilities of focused microwave radiometry for brain intracranial applications are presented. Electromagnetic and thermal simulation analysis was performed using an anatomically detailed head model and a dielectric cap as matching medium placed around it, in order to improve the sensitivity and the focusing attributes of the system. The theoretical results were compared to experimental data elicited while exploring that the sensing depth and spatial resolution of the proposed imaging method at 2.1 GHz areas located 3 cm deep inside the brain can be measured, while at 2.5 GHz, the sensing area is confined specifically to the area of interest. The results exhibit the system's potential as a complementary brain imaging tool for multifrequency in-depth passive monitoring which could be clinically useful for therapeutic, diagnostic, and research applications.


Assuntos
Eletricidade , Micro-Ondas , Modelos Anatômicos , Radiometria , Simulação por Computador , Cabeça , Humanos , Processamento de Imagem Assistida por Computador , Análise Numérica Assistida por Computador , Imagens de Fantasmas , Software
14.
Bioelectromagnetics ; 36(4): 325-9, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25726724

RESUMO

From 2008 through 2013, more than 6,000 in situ frequency selective audits, in the proximity of base stations, were conducted throughout Greece by the Greek Atomic Energy Commission (EEAE), in order to verify exposure limit compliance. EEAE is the competent national authority for protection of the general public against artificially produced non-ionizing radiation. This paper presents the first post processing and multi-parametric year statistical analysis of in situ measurement data corresponding to 4,705 audits in the whole country, compared to general public exposure levels, according to Greek legislation. The aim is to derive nationwide conclusions for the characterization of general public exposure to radiofrequency electromagnetic fields, during the last 6 years. The results' presentation includes electric field exposure ratios referring to broadband and frequency selective measurements at the highest exposure measurement point. Statistical analysis is applied to assist the data presentation and evaluation, based on selected criteria and classification parameters, including: (i) year (2008-2013); (ii) environment (urban/suburban/rural); (iii) frequency bands of selected common telecommunication services (e.g., TV, FM, GSM, DCS, UMTS); and (iv) number of service providers installed at the same site. In general, measurement results revealed that the vast majority of exposure values were below reference levels for general public exposure, as defined by Greek legislation. Data are constantly updated with the latest measurements, including emerging wireless technologies.


Assuntos
Exposição Ambiental/estatística & dados numéricos , Monitoramento de Radiação , Ondas de Rádio , Estatística como Assunto , Grécia , Humanos
15.
Radiat Prot Dosimetry ; 167(4): 502-12, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25614632

RESUMO

The scope of this paper is to comparatively present the extremely low-frequency (ELF) measurements performed at four power plants in Greece, focusing on: (a) the worst-case exposure conditions, (b) the existence of magnetic field harmonic components, (c) the technical similarities among the power plants and (d) comparison of the measured percentages of reference levels at typical working areas in the power plants. A detailed measurement methodology is proposed, including broadband on-site inspection of the working areas, weighted averaged root-mean-square and peak values of magnetic flux density, percentage of reference levels, according to 1998 ICNIRP guidelines and harmonic analysis of the multi-frequency magnetic fields. During the analysis of the occupational exposure in all power plants, the new Directive 2013/35/EU has been taken into account. The study concludes by proposing a mapping procedure of working areas into certain zones, in order to take measures for workers safety.


Assuntos
Diretivas Antecipadas/legislação & jurisprudência , Exposição Ambiental/efeitos adversos , Campos Magnéticos/efeitos adversos , Exposição Ocupacional/análise , Exposição Ocupacional/legislação & jurisprudência , Monitoramento de Radiação , União Europeia , Grécia , Humanos , Centrais Elétricas
16.
Artigo em Inglês | MEDLINE | ID: mdl-26736822

RESUMO

This paper presents the experimental configuration and procedure as well as the in-vitro assessment of Jurkat T-cells response to 1966 MHz exposure of modulated and unmodulated electromagnetic signals within a Gigahertz Transverse Electro-Magnetic (GTEM) cell. Different combinations of electric field intensity, exposure duration and modulation schemes were applied. Exposures at continuous wave (CW) signal at low intensity levels (3 V/m) did not induce any significant DNA damage, but a slight increase was observed for extreme stress levels (76.4 V/m). On the other hand, the results indicate that, at both, low and high electric field intensity UMTS (Universal Mobile Telecommunications System) signal could be statistically related to DNA damage in-vitro. Nevertheless, further experiments are required, increasing the statistical number of samples and recruiting more DNA damage endpoints before conclusive statements are drawn.


Assuntos
Campos Eletromagnéticos , Ensaio Cometa , Dano ao DNA/efeitos da radiação , Humanos , Células Jurkat , Linfócitos T/citologia , Linfócitos T/metabolismo , Linfócitos T/efeitos da radiação , Temperatura
17.
Bioelectromagnetics ; 35(4): 273-83, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24523224

RESUMO

The effects of radiofrequency (RF) exposure on wake and sleep electroencephalogram (EEG) have been in focus since mobile phone usage became pervasive. It has been hypothesized that effects may be explained by (1) enhanced induced fields due to RF coupling with the electrode assembly, (2) the subsequent temperature increase around the electrodes, or (3) RF induced thermal pulsing caused by localized exposure in the head. We evaluated these three hypotheses by means of both numerical and experimental assessments made with appropriate phantoms and anatomical human models. Typical and worst-case electrode placements were examined at 900 and 2140 MHz. Our results indicate that hypothesis 1 can be rejected, as the induced fields cause <20% increase in the 10 g-averaged specific absorption rate (SAR). Simulations with an anatomical model indicate that hypothesis 2 is also not supported, as the realistic worst-case electrode placement results in a maximum skin temperature increase of 0.31 °C while brain temperature elevations remained <0.1 °C. These local short-term temperature elevations are unlikely to change brain physiology during the time period from minutes to several hours after exposure. The maximum observed temperature ripple due to RF pulses is <0.001 °C for GSM-like signals and <0.004 °C for 20-fold higher pulse energy, and offers no support for hypothesis 3. Thus, the mechanism of interaction between RF and changes in the EEG power spectrum remains unknown.


Assuntos
Artefatos , Eletroencefalografia , Ondas de Rádio/efeitos adversos , Telefone Celular , Eletrodos , Humanos , Modelos Anatômicos , Imagens de Fantasmas , Temperatura
18.
Artigo em Inglês | MEDLINE | ID: mdl-25571072

RESUMO

Pneumothorax may cause serious health problems and often death if medical and surgical treatment is delayed. The absence of reliable, safe, portable and easy-to-use equipment in the ambulance is the primary clinical motivation of this work. We investigate pneumothorax diagnostic performance and sensitivity of a dual patch antenna system (sensor). The operation frequency range is set to 1-4 GHz. Parametric study is conducted using simplified rectangular tissue numerical models. Variation of S12 parameter, related to frequency, is compared in order to distinguish healthy and pneumothorax cases, reaching a difference of 20.1 dB, at 1.87 GHz. MRI-based anatomic models are also modified in order to simulate pneumothorax incident, in realistic clinical case. The best performance configuration scenario is applied onto the modified anatomic models, revealing satisfactory sensor performance (7.1 dB, at 2.3 GHz). Sensor diagnostic ability reaches 1 cm of air thickness. The paper concludes with proposed design specifications for thorax experimental phantom.


Assuntos
Micro-Ondas , Pneumotórax/diagnóstico , Simulação por Computador , Desenho de Equipamento , Humanos , Imageamento por Ressonância Magnética , Modelos Biológicos , Tórax/anatomia & histologia
19.
Artigo em Inglês | MEDLINE | ID: mdl-25571222

RESUMO

The aim of the paper is to assess the interaction of the neural potentials during a time discrimination psychoacoustic task. Ten subjects participated in the experiment and were asked about the equality of two acoustic pulses: one reference of 500ms and one trial that varied from 420ms to 620ms. During the experimental procedure, Electroencephalogram (EEG) and Event Related Potential (ERP) signals were recorded. The analysis combines results from Continuous Wavelet signal processing and subjects responses which were analyzed based on psychoacoustic theory. The Wavelet Coherence metric index is employed to assess the interaction of neural potentials. The results indicate the points at which the duration of the trial pulse is equal to 560ms and 460ms as the minimum and maximum of the Wavelet Coherence metric index, respectively. This observation is valid in most electrodes, for all basic EEG rhythms, revealing in parallel the differentiation of the gamma rhythm, in relation to the others. These maximum and minimum values are correlated to the Just Noticeable Difference (JND) in pulses duration, calculated by the psychoacoustic analysis.


Assuntos
Eletroencefalografia , Potenciais Evocados/fisiologia , Análise de Ondaletas , Acústica , Adulto , Eletrodos , Feminino , Humanos , Masculino , Neurônios/fisiologia , Oscilometria , Psicoacústica , Processamento de Sinais Assistido por Computador
20.
Artigo em Inglês | MEDLINE | ID: mdl-25571223

RESUMO

The aim of the paper is the assessment of neural potentials disorder during a differential sensitivity psychoacoustic procedure. Ten volunteers were asked to compare the duration of two acoustic pulses: one reference with stable duration of 500 ms and one trial which varied from 420 ms to 620 ms. During the discrimination task, Electroencephalogram (EEG) and Event Related Potential (ERP) signals were recorded. The mean Relative Wavelet Energy (mRWE) and the normalized Shannon Wavelet Entropy (nSWE) are computed based on the Discrete Wavelet analysis. The results are correlated to the data derived by the psychoacoustic analysis on the volunteers responses. In most of the electrodes, when the duration of the trial pulse is 460 ms and 560 ms, there is an increase and a decrease in nSWE value, respectively, which is determined mostly by the mRWE in delta rhythm. These extrema are correlated to the Just Noticeable Difference (JND) in pulses duration, calculated by psychoacoustic analysis. The dominance of delta rhythm during the whole auditory experiment is noteworthy. The lowest values of nSWE are noted in temporal lobe.


Assuntos
Eletroencefalografia , Potenciais Evocados/fisiologia , Psicoacústica , Análise de Ondaletas , Adulto , Ritmo Delta , Entropia , Feminino , Audição , Humanos , Masculino , Modelos Estatísticos , Processamento de Sinais Assistido por Computador , Som , Lobo Temporal/patologia , Fatores de Tempo
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