RESUMO
A refractive index sensor based on an on-chip silicon nitride (Si3N4) ridge waveguide long-range surface plasmon polariton (LRSPP) is theoretically designed. The waveguide sensor consists of a gold film to enable the plasmonic resonance on top of a Cytop polymer layer. A proper finite element method was used to design and optimize the geometric parameters at the optical wavelength of 633 nm. In addition, the spectral performance was evaluated using the transfer matrix method from 580 to 680 nm. The redshifted interference spectrum results from an increasing analyte refractive index. The sensitivities of 6313 dB/cm/RIU and 251.82 nm/RIU can be obtained with a 400 nm wide and 25 nm thick Au layer. The proposed sensor has the potential for point-of-care applications considering its compactness and simplicity of construction.
RESUMO
In this work a plasmonic sensor with a D-Shaped microstructured optical fiber (MOF) is proposed to detect a wide range of analyte refractive index (RI ;na) by doping the pure silica (SiO2) core with distinct concentrations of Germanium Dioxide (GeO2), causing the presentation of high spectral sensitivity. In this case, the fiber is shaped by polishing a coating of SiO2, on the region that will be doped with GeO2, in the polished area, a thin gold (Au) layer, which constitutes the plasmonic material, is introduced, followed by the analyte, in a way which the gold layer is deposited between the SiO2. and the analyte. The numerical results obtained in the study shows that the sensor can determine efficiently a range of 0.13 refractive index units (RIU), with a limit operation where na varies from 1.32 to 1.45. Within this application, the sensor has reached an average wavelength sensitivity (WS) of up to 11,650.63 nm/RIU. With this level of sensitivity, the D-Shaped format and wide range of na detection, the proposed fiber has great potential for sensing applications in several areas.
Assuntos
Germânio , Fibras Ópticas , Ressonância de Plasmônio de Superfície , Ouro , Dióxido de Silício , Ressonância de Plasmônio de Superfície/instrumentaçãoRESUMO
Hypertension is a leading cause of death and disability globally, and its prevalence continues to accelerate. The cardiovascular effects of the flavonoid tiliroside have never been reported. In this work, using complementary in vivo and in vitro approaches, we describe the antihypertensive effect of tiliroside and the underlying mechanisms involved in the reduction of blood pressure. Tiliroside (1, 5 or 10 mg/kg) induced a dose-dependent long-lasting decrease in blood pressure in conscious DOCA-salt hypertensive rats that was accompanied by an increased heart rate. Tiliroside also induced a concentration-dependent vasodilation of mesenteric resistance arteries precontracted with phenylephrine. Removal of the endothelium or pretreatment of the preparation with L-NAME or indomethacin did not modify the vasodilator response for tiliroside. When vessels were precontracted with a high K⺠(50 mM) solution, tiliroside exhibited a vasodilator effect similar to that observed in vessels precontracted with phenylephrine. Experiments carried out in nominally Ca²âº-free solution showed that tiliroside antagonized CaCl2-induced contractions. Moreover, tiliroside reduced the rise in intracellular Ca²âº concentration induced by membrane depolarization in vascular smooth muscle cells. Finally, tiliroside decreased the voltage-activated peak amplitude of the L-type Ca²âº channel current in freshly dissociated vascular smooth muscle cells from mesenteric arteries. Altogether, our results point to an antihypertensive effect of tiliroside due to a reduction in peripheral resistance through blockage of voltage-activated peak amplitude of the L-type Ca²âº channel in smooth muscle cells.
Assuntos
Anti-Hipertensivos/farmacologia , Flavonoides/farmacologia , Músculo Liso Vascular/efeitos dos fármacos , Vasodilatadores/farmacologia , Animais , Pressão Sanguínea/efeitos dos fármacos , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/fisiologia , Endotélio Vascular/fisiopatologia , Hipertensão/induzido quimicamente , Hipertensão/fisiopatologia , Artérias Mesentéricas/efeitos dos fármacos , Artérias Mesentéricas/fisiopatologia , Músculo Liso Vascular/fisiologia , Músculo Liso Vascular/fisiopatologia , Fenilefrina/farmacologia , Ratos , Vasodilatação/efeitos dos fármacosRESUMO
The association of biliary atresia (BA) with congenital heart diseases has been extensively described, and there are a number of reports on the outcomes of patients in this group who undergo liver transplantation (LT). The intraoperative management and the timing of LT for patients with end-stage liver disease are matters of debate, especially when complex heart diseases are involved. This report describes the outcome after LT for a pediatric recipient with BA and hypoplastic left heart syndrome. The patient underwent Norwood-Sano and Glenn procedures for heart palliation before LT. He was cyanotic, was severely malnourished, and had complications secondary to chronic liver failure. At the time of transplantation, the child was 16 months old and weighed 5175 g. Despite the critical clinical scenario and the long hospitalization period, there were no cardiac, vascular, or biliary complications after LT. At the age of 48 months, the patient was awaiting the final cardiac repair. In conclusion, the presence of complex cardiac malformations may not be a contraindication to LT. An experienced surgical team and a multidisciplinary approach are key to a successful outcome.