RESUMO
This study aimed to design and fabricate planar constricted-expanded structures that are integrated into paper-based channels in order to enhance their chaotic advection and improve their mixing performance. Chromatography papers were used to print paper-based microfluidics using a solid-wax printer. Three different constricted-expanded structures-i.e., zigzag, crossed, and curved channels-were designed in order to evaluate their mixing performance in comparison with that of straight channels. A numerical simulation was performed in order to investigate the mixing mechanism, and to examine the ways in which the planar constricted-expanded structures affected the flow patterns. The experimental and numerical results indicated that the proposed structures can successfully mix confluents. The experimental results revealed that the mixing indices (σ) rose from the initial 20.1% (unmixed) to 34.5%, 84.3%, 87.3%, and 92.4% for the straight, zigzag, curved, and cross-shaped channels, respectively. In addition, the numerical calculations showed a reasonable agreement with the experimental results, with a variation in the range of 1.0-11.0%. In future, we hope that the proposed passive paper-based mixers will be a crucial component in the application of paper-based microfluidic devices.
Assuntos
Dispositivos Lab-On-A-Chip , Microfluídica , Simulação por Computador , Desenho de EquipamentoRESUMO
OBJECTIVE: To study the chemical constituents from ethyl acetate extract of Sedum aizoon. METHODS: The chemical constituents were isolated by column chromatography and identified by MS and NMR. RESULTS: 11 compounds were isolated and identified as: protocatechuic acid (1), caffeic acid (2), 5,7-dihydroxy chromone (3), methyl gallate (4), ethyl gallate (5), myricetin (6), luteolin (7), cynaroside (8), 3',4',5,7-tetrahydroxy flavanone (9), iriflophene (10) and iriflophene-2-O-ß-D-glucoside (11). CONCLUSION: Compounds 1-3 and 8-11 are the first report of isolation from this plant.
