Avaliação da função autonômica cardíaca e da sobrecarga cardiovascular de bombeiros militares durante turno de serviço operacional

Dissertação (mestrado) — Universidade de Brasília, Faculdade de Educação Física, Programa de Pós-Graduação Stricto-Sensu em Educação Física, 2016.Introdução: As rotinas de trabalho dos bombeiros incluem extinção de incêndios, salvamentos e atendimento a emergências médicas. Tais atividades expõem esses profissionais a riscos ocupacionais e a intensa sobrecarga física e emocional. Objetivos: Avaliar a função autonômica cardíaca (FAC), em um dia de rotina profissional habitual em comparação com uma condição basal, a sobrecarga cardiovascular durante um turno de trabalho e a aptidão cardiorrespiratória (ACR) de bombeiros. Indivíduos: Foram selecionados, por conveniência, 30 bombeiros do sexo masculino (35-47 anos), sem restrições médicas e/ou doenças cardiometabólicas. Métodos: Foram avaliados índices temporais e espectrais da variabilidade da frequência cardíaca (VFC) na condição basal em laboratório (AVA1), no início de um turno diurno de trabalho (AVA2) e ao seu término (AVA3). A sobrecarga cardiovascular foi avaliada por meio do comportamento da frequência cardíaca, registrada ao longo do plantão. A ACR foi estimada em repouso por questionário validado. Foram comparados os valores da VFC nos 3 momentos, calculados os tempos absolutos e relativos de permanência em cada zona de intensidade de esforço ao longo do turno e avaliada a correlação entre os índices da VFC com a ACR . Resultados: Observou-se diminuição da modulação vagal em AVA3, expressa pela redução significativa do PNN50% na postura ortostática ao final do turno: 0,35 (0,0 - 60,3), comparativamente aAVA1: 2,6 (0,0 - 31,5). 97,3 ± 4,2% do tempo de trabalho foi de atividades leves e cerca de 2% de intensidades vigorosas/muito vigorosas. Houve correlação positiva (p<0,05) entre PNN50%, RMSSD; AABF e AAAF em AVA1 e AVA3 com a ACR (0,37<rs<0,46; 0,35<rs<0,49). Conclusões: A atividade desses bombeiros ocorreu majoritariamente em zona de intensidade cardiovascular leve, intercalada com curtos períodos de elevadíssima sobrecarga cardiovascular. Observou-se redução da modulação vagal ao término de um turno diurno de trabalho e associação da VFC com a ACR.Projeto apoiado pelo Conselho Nacional de Desenvolvimento Científico e Tecnológico- CNPq.Introduction: Firefighters' work routines include firefighting, rescue, and medical emergencies. Such activities expose these professionals to occupational hazards and intense physical and emotional overload. Objectives: To evaluate the cardiac autonomic function (CAF) in a professional routine day compared to a baseline condition, the cardiovascular overload during a work shift and the cardiorespiratory fitness (CRF) of firefighters. Group: A convenient sample of 30 male firefighters (35-47 yrs old) without medical restrictions and / or cardiometabolic diseases was selected. Methods: We evaluated temporal and spectral indexes of heart rate variability (HRV) at the baseline laboratory condition (EVA1), at the beginning of a work shift (EVA2) and at the end of it (EVA3). Cardiovascular overload was assessed by heart rate profile, recorded throughout the shift. CRF was estimated at rest by validated questionnaire. HRV values were compared at 3 moments, absolute and relative times were calculated in each zone of effort intensity throughout the shift, and the correlations between HRV and CRF indexes were also evaluated. Results: A decrease in vagal modulation in EVA3 was observed, expressed by a significant reduction of the PNN50% in the orthostatic posture at the end of the shift: 0.35 (0.0-60.3), as compared to EVA1: 2.6 (0.0 - 31.5). 97.3±4.2% of working time was of light activities and about 2% of vigorous/very vigorous intensities. There was a positive correlation (p <0.05) between PNN50%, RMSSD; AABF and AAAF in EVA1 and EVA3 with CRF (0.37 <rs <0.46; 0.35 <rs <0.49). Conclusions: The activity of these firefighters occurred mainly in a zone of light cardiovascular intensity, interspersed with short periods of very high cardiovascular overload. A reduction of vagal modulation was observed at the end of a day shift of work as well as an association between HRV and CRF

Estrogen Receptor-Beta Gene Polymorphism in women with Breast Cancer at the Imam Khomeini Hospital Complex, Iran

ER-alpha and ER-beta genes have been proven to play a significant role in breast cancer. Epidemiologic studies have revealed that age-incidence patterns of breast cancer in Middle East differ from those in the Western countries. Two selected coding regions in the ER-β gene (exons 3 and 7) were scanned in Iranian women with breast cancer (150) and in healthy individuals (147). PCR single-strand conformation polymorphism was performed. A site of silent single nucleotide polymorphism was found only on exon 7. The SNP was found only in breast cancer patients (5.7%) (χ2 = 17.122, P = 0.01). Codon 392 (C1176G) of allele 1 was found to have direct association with the occurrence of lymph node metastasis. Our data suggest that ER-β polymorphism in exon 7 codon 392 (C1176G) is correlated with various aspects of breast cancer and lymph node metastasis in our group of patients

Turbulent plumes in asymmetric rough Rayleigh-Bénard cell

International audienc

CHANGES IN CARDIOPULMONARY FUNCTION DURING EXERCISE FROM PRE- TO POST-PUBERTY

Sam Robert Emerson1,Stephanie P. Kurti1, Sara K. Rosenkranz2, Joshua R. Smith1,&Craig A. Harms1, FACSM 1Departments of Kinesiology and 2Human Nutrition, Kansas State University, Manhattan, Kansas Ventilatory constraint, i.e. expiratory flow limitation (EFL), during exercise leads to an increased work of breathing, dyspnea, respiratory muscle fatigue, and adverse cardiovascular outcomes which can all affect exercise tolerance. EFL is due to an imbalance between pulmonary capacity and ventilatory demand during exercise. We have recently reported that EFL is highly prevalent in prepubescent children and is much greater than that reported in adults. It is unknown how maturation from pre- to post-puberty affects pulmonary function, specifically EFL, during exercise. PURPOSE: Therefore, the purpose of this longitudinal study was to investigate the changes in cardiopulmonary function from pre- to post-puberty. METHODS: Nineteen children (ages 12-16 yrs; 10 boys, 9 girls) were recruited from 40 prepubescent children who completed testing in our lab ~5 years ago. Subjects completed pulmonary function tests (PFTs) before and after an incremental exercise test to exhaustion (VO2max) on a cycle ergometer. EFL was determined using the percent tidal volume (VT) overlap method. RESULTS: Sixteen of the 19 subjects (8 boys, 8 girls; 84%) exhibited EFL pre-puberty. Six of the 19 subjects (4 boys, 2 girls; 32%) exhibited EFL post-puberty. Of the subjects that experienced EFL post-puberty, all had experienced EFL pre-puberty. Forced vital capacity (FVC) significantly increased (~100%) from 2.1 ± 0.4 L (mean ± SD) at the pre-puberty assessment to 4.3 ± 0.7 L at the post-puberty assessment. Absolute VO2max significantly increased (~125%) from 1.09 ± 0.3 L/min to 2.38 ± 0.6 L/min; relative VO2max significantly increased (~23%) from 32.4 ± 8.4 ml/kg/min to 38.1 ± 7.3 ml/kg/min.Maximal ventilation significantly increased (~120%) from 46.4 ± 10.3 L/min to 98.6 ± 20.8 L/min. VE/VCO2 coupling at VO2max significantly decreased (~12%) from 43.5 ± 6.4 at pre-puberty to 37.5 ± 4.0 at post-puberty. CONCLUSION: These data suggest that the prevalence of EFL declines as children mature from pre- to post-puberty, likely due to greater increase in lung volume (FVC) than increases in VEmax and VO2max, accompanied by a decrease in VE/VCO2 coupling. This increase in pulmonary function at maximal exercise may contribute to the improved exercise capacity seen in adolescents and adults compared to children

Localized Electrochemical Oxidation of Thin Nb Films in Microscopic and Nanoscopic Dimensions

The mechanism and kinetics of localized anodic oxidation of thin Nb films are investigated by measurements in an electrochemical microcell and in the so-called nanocell, which is formed by water condensation between an AFM-tip and the Nb-substrate in humid air. In both, the microscopic and nanoscopic oxidation, the thickness of generated oxide structures increases linearly with the applied potential in accordance with the so-called high field growth model. The oxide growth factor depends on the polarization time and reaches in both cases for long times a value of about 2.8 nm/V. In the case of AFM tip-induced oxidation at constant voltage the oxide growth rate decreases rapidly with the polarization time, which is in good agreement with the proposed models including a rapid build-up of space charge within the oxide in the initial oxidation stages. The increase of the oxide thickness is limited by the thickness of the thin Nb layer. An experimental procedure for checking the complete local nanooxidation of thin Nb films is proposed and the possibility for preparation of lateral metal-insulator-metal (MIM) structures is demonstrated. (c) 2005 Elsevier B.V. All rights reserved