排序方式: 共有45条查询结果,搜索用时 15 毫秒
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Hydrodynamic control of droplet division in bifurcating microchannel and its application to particle synthesis 总被引:1,自引:0,他引:1
Yamada M Doi S Maenaka H Yasuda M Seki M 《Journal of colloid and interface science》2008,321(2):401-407
We describe herein a microfluidic system for active and precise control of droplet division at a bifurcation point in a microchannel. Water-in-oil or oil-in-water droplets, which were initially formed at a T-junction, were introduced into the bifurcation point, and then divided into two daughter droplets. By continuously introducing 'tuning flow' into the downstream of one of the branch channels, and by controlling the flow rates distributed into the two branch channels, the sizes of the daughter droplets could be precisely tuned. The ratio of the volumetric flow rates into the branch channels was estimated by regarding the microchannel network as a resistive circuit. In addition, we performed synthesis of monodispersed polymer particles with controlled sizes utilizing the presented system. The ability to hydrodynamically control the droplet sizes will open new possibilities not only for producing useful emulsions, but also for conducting controlled chemical and biochemical reactions in a confined space. 相似文献
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Continuous and size-dependent sorting of emulsion droplets using hydrodynamics in pinched microchannels 总被引:1,自引:0,他引:1
Maenaka H Yamada M Yasuda M Seki M 《Langmuir : the ACS journal of surfaces and colloids》2008,24(8):4405-4410
In this report, a microfluidic system is presented for continuous and size-dependent separation of droplets utilizing microscale hydrodynamics. The separation scheme is based on laminar-flow focusing and spreading in a pinched microchannel, referred to as "pinched flow fractionation (PFF)", which was previously developed for the size-dependent separation of solid particles, such as polymer microparticles or cells. By simply introducing emulsion and the continuous phase into a microchannel, continuous separation could be achieved without using complicated operations or devices. We first examined whether this scheme could be applied for droplets, by using a pinched microchannel with one outlet, and observed the behaviors of monodisperse droplets generated at the upstream T-junction. Analysis via high-speed imaging revealed that the length of the pinched segment is critical for precise separation of droplets. Then, separation of a polydisperse oil-in-water emulsion that was prepared previously was demonstrated using a microfluidic device equipped with multiple outlets. These results showed the ability of the presented system to sort or select specific-sized droplets easily and accurately, which would be difficult to achieve using normal-scale schemes, such as centrifugation or filtration. 相似文献
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Kanamori T Masaki Y Mizuta M Tsunoda H Ohkubo A Sekine M Seio K 《Organic & biomolecular chemistry》2012,10(5):1007-1013
We have previously reported DNA triplexes containing the unnatural base triad G-PPI·C3, in which PPI is an indole-fused cytosine derivative incorporated into DNA duplexes and C3 is an abasic site in triplex-forming oligonucleotides (TFOs) introduced by a propylene linker. In this study, we developed a new unnatural base triad A-ψ·C(R1) where ψ and C(R1) are base moieties 2'-deoxypseudouridine and 5-substituted deoxycytidine, respectively. We examined several electron-withdrawing substituents for R1 and found that 5-bromocytosine (C(Br)) could selectively recognize ψ. In addition, we developed a new PPI derivative, PPI(Me), having a methyl group on the indole ring in order to achieve selective triplex formation between DNA duplexes incorporating various Watson-Crick base pairs, such as T-A, C-G, A-ψ, and G-PPI(Me), and TFOs containing T, C, C(Br), and C3. We studied the selective triplex formation between these duplexes and TFOs using UV-melting and gel mobility shift assays. 相似文献
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Hirosuke Watanabe Masashi Furukawa Tadahiko Takata Masahide Yamamoto 《Macromolecular Symposia》2000,159(1):131-142
The application of the low‐temperature plasma method, the excimer laser treatment method and the corona‐discharge method to aramid) were discussed, presenting an overview of current trends and developments in this area. 相似文献