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Adv Exp Med Biol ; 1232: 99-104, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31893400


The incidence of stress-induced psychological and somatic diseases has been increasing rapidly, and it is important to clarify the neurophysiological mechanisms of stress response in order to establish effective stress management methods. We previously reported that the prefrontal cortex (PFC) plays an important role in stress response. In the present study, we employed near-infrared spectroscopy (NIRS) and electroencephalography (EEG) to investigate the characteristics of PFC activity during mental arithmetic tasks. A two-channel NIRS device was used to measure hemoglobin (Hb) concentration changes in the bilateral PFC during a mental arithmetic task (2 min) in normal adults. Simultaneously, EEG was used to also measure bilateral PFC activity during the same task. We evaluated concentration changes of oxy-Hb induced by the task while analyzing α wave changes using power spectrum analysis. It was observed that oxy-Hb in the bilateral PFC increased significantly during the task (p < 0.05), while α wave power in the PFC decreased significantly (p < 0.01). The present results indicate that mental stress tasks caused the activation of the bilateral PFC. Simultaneous measurements of NIRS and EEG are useful for evaluating the neurophysiological mechanism of stress responses in the brain.

Eletroencefalografia , Fenômenos Eletromagnéticos , Oxigênio , Espectroscopia de Luz Próxima ao Infravermelho , Estresse Psicológico , Adulto , Hemoglobinas/análise , Humanos , Oxigênio/sangue , Oxiemoglobinas/análise , Córtex Pré-Frontal/fisiopatologia , Estresse Psicológico/fisiopatologia
Adv Exp Med Biol ; 1232: 291-297, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31893423


We present an IoT-based monitoring system for healthcare that allows for long-term measurements of blood pressure (BP), heart rate (HR), and body weight (BW), as well as near-infrared spectroscopy (NIRS) for measurement of prefrontal cortex (PFC) activity. To verify the applicability of the system, it was set up in a local fitness gym for a preliminary study. A total of 39 subjects, selected from members of the gym, participated in the study. We analyzed the BP, HR, and BW data, collected from the subjects over one half-year. In addition, to assess the degree of mental stress of the subjects, we analysed left-right asymmetry of the PFC activity using the laterality index at rest (LIR) of the NIRS parameter. Results show that the subjects were able to measure their physiological data by themselves when they visited the gym, after being instructed how to perform the measurements. Furthermore, the results also indicate that ordinary people can continuously monitor physiological functions such as brain function in a non-medical facility, such as a fitness gym.

Monitorização Fisiológica , Córtex Pré-Frontal , Espectroscopia de Luz Próxima ao Infravermelho , Idoso , Feminino , Lateralidade Funcional , Frequência Cardíaca , Humanos , Masculino , Pessoa de Meia-Idade , Monitorização Fisiológica/instrumentação , Monitorização Fisiológica/métodos , Monitorização Fisiológica/normas , Autoexame/normas , Estresse Psicológico
Adv Exp Med Biol ; 1232: 315-322, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31893426


We present an unobtrusive cuff-less sphygmomanometer based on contact-type and optical pulse sensors for continuous and minimally invasive monitoring of blood pressure (BP). We developed a cuff-less sphygmomanometer that utilizes the pulse arrival time (PAT) to estimate continuous BP. To assess its accuracy, we recruited 10 healthy subjects in whom we carried out BP studies using the cuff-less sphygmomanometer compared with a standard cuff-type device in a stationary sitting patient. Preliminary results showed that the mean difference (MD) of estimated systolic blood pressure and diastolic blood pressure were 0.96 ± 9.6 (mean ± SD) mmHg and 1.14 ± 7.5 mmHg, respectively, compared to the control. The corresponding correlation between the estimated BP values and controls were 0.78 for systolic blood pressure (p < 0.01) and 0.69 for diastolic blood pressure (p < 0.01); thus, there were significant correlations. These results suggest that the developed cuff-less sphygmomanometer has the potential for continuous BP monitoring. Finally, we conducted a preliminary study of simultaneous monitoring of cuff-less BP and near-infrared spectroscopy to evaluate the potential for assessment of autonomic nervous system functions during mental stress tasks.

Determinação da Pressão Arterial , Esfigmomanômetros , Adulto , Sistema Nervoso Autônomo/fisiologia , Pressão Sanguínea , Determinação da Pressão Arterial/instrumentação , Eletrocardiografia , Frequência Cardíaca , Humanos , Masculino , Monitorização Fisiológica/instrumentação , Monitorização Fisiológica/normas , Esfigmomanômetros/normas , Adulto Jovem
Phys Rev Lett ; 92(6): 066102, 2004 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-14995256


We have measured the visible light spectrum emitted by hydrogen atoms adsorbed on an Ni(110) surface, excited by the tunneling current from the scanning tunneling microscope. The spectrum contains periodic fine structures, whose period corresponds to the vertical vibrational energy of the adsorbed H atom. This energy showed the expected isotope shift when H was replaced by deuterium, and further it depended on the H-atom chain length.

Phys Rev B Condens Matter ; 51(4): 2229-2238, 1995 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-9978972
Phys Rev B Condens Matter ; 36(9): 4990-5000, 1987 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-9943519
Phys Rev B Condens Matter ; 36(6): 3052-3058, 1987 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-9943213
Phys Rev B Condens Matter ; 36(3): 1803-1806, 1987 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-9943023
Phys Rev B Condens Matter ; 34(10): 6804-6812, 1986 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-9939327