38 research outputs found

    Coherent and Dissipative Coupling in a Magnetomechanical System

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    Hybrid elastic and spin waves hold promises for energy-efficient and versatile generation and detection of magnetic signals, with potentially long coherence times. Here we report on the combined elastic and magnetic dynamics in a one-dimensional magnetomechanical crystal composed of an array of magnetic nanostripes. Phononic and magnonic modes are impulsively excited by an optical ultrafast trigger and their decay is monitored by time-resolved magneto-optical Kerr effect. Complementary Brillouin light scattering measurements and micromagnetic simulations concur in a unified picture, in which the strength and degree of mixing of coherent and dissipative coupling of the quasiparticles are determined quantitatively

    Distribution of the pacemaker HCN4 channel mRNA and protein in the rabbit sinoatrial node.

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    Several studies of the pacemaker mechanisms in mammalian cells, most of which were carried out in cells isolated from the rabbit sinoatrial node (SAN), have highlighted the role of the If current. While the distribution of Hyperpolarization-activated Cyclic Nucleotide-gated (HCN) channels, the molecular correlates of f-channels, is known at the mRNA level, the identification of f-channel proteins in this tissue is still undetermined. Here we investigate HCN protein expression in the rabbit pacemaker region. We found that HCN4 is the main isoform, and set therefore to analyze its distribution within the SAN and surrounding areas with the aim of correlating protein expression and pacemaking function. The analysis was carried out in tissue slices and single cells of the intercaval area, which includes the crista terminalis (CT), the SAN, and the septum interatrialis (SI). Immunolabeling, in situ hybridization, qRT-PCR analysis, and electrophysiological recordings identified the SAN as a region characterized by high HCN4 signal and current levels, while the expression in the CT and in the SI was either negligible or absent. Detailed analysis of the central SAN area showed that cells are predominantly distributed in islets interconnected by cell prolongations, and single-cell HCN4 labeling suggested sites of channel clustering. Our data indicate that in the rabbit SAN, HCN4 proteins are major constituents of native f-channels, and their distribution matches closely the SAN as defined morphologically and electrophysiologically. Until recently, the SAN was identified as the region where Cx43 and atrial natriuretic peptide are not expressed; we propose here that expression of HCN4 is an appropriate tool to map and identify the cardiac SAN pacemaker region

    Uma concepção popular sobre a esquistossomose mansônica: os modos de transmissão e prevenção na perspectiva de gênero A popular concept of schistosomiasis mansoni: modes of transmission and prevention in the perspective of gender differences

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    Estudo sobre as concepções e práticas populares acerca da transmissão e prevenção das parasitoses, com ênfase para a esquistossomose mansônica. Explora a existência de um sistema popular de cuidados de saúde que mescla elementos da biomedicina e da medicina tradicional como forma de compreender e manejar os fenômenos de saúde/doença. Descreve as diferenças entre morbidade e sexo/gênero na concepção dos sujeitos entrevistados. Apresenta o discurso popular sobre as parasitoses, discutindo as dificuldades das ações de controle. Considera as contradições entre hábitos e valores culturais e as medidas de controle conhecidas, criticando a imprecisão das ações educativas nos programas oficiais de intervenção.<br>This is a study on popular ideas, beliefs and practices concerning the transmission and prevention of parasitic diseases, specifically schistosomiasis mansoni. The author explored the existence of a popular belief system within the health care system, combining elements from biomedicine and folk medicine for the understanding and management of the health/disease phenomenon. The study describes the differences in perception of morbidity and gender among the interviewwees. Finally, the study presents popular discourse on parasitic diseases and discusses diffculties with control measures. It considers the contradiction between cultural values and habits and conventional control measures, critically assessing the lack of precision in health education measures under government prevention programs
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