Experimental and numerical study has been carried on the proposed on design of the micromixer based on the unbalanced split and collision of the fluids streams. The main microchannel is split into two sub-channels and then recombines after a certain distance. The shape of the split sub-channels is rhombic with major subchannel crossing the minor sub-channel. Numerical analysis has been carried out by solving Navier-Stokes equation. The experimental study has been carried on the device fabricated using standard soft lithography technique. Mixing analysis has been performed using inverted fluorescence microscope. The micromixer with balanced collisions (equal width of sub-channels) shows poor mixing quality. The collision of the fluids streams are effective in enhancing mixing as the level of unbalance is increased by adjusting the widths of the sub-channels.
Chemoselective Mukaiyama aldol products derived from the mixed monosilyl acetals and silyl ketene acetals were obtained through discriminative activation of the alkoxy group on the acetal using appropriate oxophilic catalysts (such as BF3⋅OEt2 and Cu(OTf)2-diphenylphosphoric acid). For more information, see the Communication by H.-J. Ha, J. W. Yang, et al. on page 16432 ff.
In this study, an integrated micro/nanofluidic system for protein analysis was presented. The device is comprised of a micromixer and a preconcentrator with a separation column. The integrated micromixer based on unbalanced split and cross collision of fluid streams is passive and planar, which is easy to fabricate and integrate to the microfluidic system. The preconcentrator has nanochannels formed by the electrical breakdown of polydimethylsiloxane (PDMS) membrane using a high electrical shock, without any nano-lithographic process. Micromixer and preconcentrator were used for sample preparation (tagging of protein for detection) and concentration of protein, consecutively. Proteins were electrokinetically trapped near the junction of micro/nanochannels.
The present study investigates the thermal and hydraulic performance of the microjet array cooling system for thermal management of a high-power light-emitting diode array. Three-dimensional numerical analyses were performed for steady incompressible turbulent flow and conjugate heat transfer through a finite volume solver. The performances of several microjet array configurations, viz., 1-jet, 4-jet, 9-jet, 13-jet, and 16-jet arrays, were analyzed at two flow rates and top-cavity heights. The design optimization of a 4-jet array cooling system was performed using a multi-objective evolutionary algorithm. For the optimization, two design variables, viz., ratio of the nozzle diameter and height of the top cavity and ratio of the height and length of the top cavity, were selected. The thermal resistance and pressure drop were selected as the objective functions of the design. The Pareto-optimal solutions were obtained and discussed in view of the thermal resistance and pressure drop and sensitivity of design variables to objective functions.
Rice straw is a potential feedstock for cellulosic ethanol, since it is the most abundant agricultural waste in the world and contains starch. The structural configuration of starch makes it easy to hydrolyze, which consequently could increase ethanol yields. In this study, effects of starch in rice straw on ethanol production were investigated. A transgenic rice straw with high vegetative starch content and conventional rice straw were pretreated using dilute acid, hot water, or ammonium hydroxide. To evaluate starch solubility during the pretreatments, pretreated samples were either washed or unwashed prior to enzymatic hydrolysis. Starch or cellulose were solubilized and hydrolyzed during all three pretreatments. As a result, unwashed samples showed up to 60% and 79% higher glucose yield and ethanol yield, respectively, than washed samples. In addition, greater starch content in transgenic rice straw led to increased ethanol yields compared to control rice straw. Unwashed transgenic samples pretreated with dilute acid, hot water, or ammonium hydroxide achieved ethanol yields of 17.5%, 14.9%, and 20.4% g g-1 biomass, respectively.
In this paper, we propose the eccentricity-compensating actuator mechanism for near-field (NF) optical disc drives. In this proposed dual-stage compensating actuator mechanism, the disc-spindle unit is actuated instead of the solid immersion lens (SIL) along the tracking axis to cancel out an eccentricity less than 20 µmpp (pp: peak to peak), which is the required criterion for NF discs of 160 nm track pitch. As a result, the proposed method enables the decrease in the required residual tracking error to lower than the criteria of 4.5 nm in NF optical disc drive (ODD) even when using the tracking servo of moderate performance. The proposed active eccentricity compensation method can be effective and applicable to dealing with the eccentricity problem in NF ODD, which we verified experimentally.
Photosensitizers (PSs) used in photodynamic therapy (PDT) have been developed to selectively destroy tumor cells. However, PSs recurrently reside on the extracellular matrix or affect normal cells in the vicinity, causing side effects. Additionally, the membrane stability of tumor cells and normal cells in the presence of reactive oxygen species (ROS) has not been studied, and the effects of ROS at the membrane level are unclear. In this work, we elucidate the stabilities of model membranes mimicking tumor cells and normal cells in the presence of ROS. The model membranes are constructed according to the degree of saturation in lipids and the bilayers are prepared either in symmetric or asymmetric form. Interestingly, membranes mimicking normal cells are the most vulnerable to ROS, while membranes mimicking tumor cells remain relatively stable. The instability of normal cell membranes may be one cause of the side effects of PDT. Moreover, we also show that ROS levels are controlled by antioxidants, helping to maintain an appropriate amount of ROS when PDT is applied.
'%3e%3cg id='b'%3e%3cpath id='a' stroke='%23000' stroke-width='2' d='M-6-25H6m-12 3H6m-12 3H6'/%3e%3cuse xlink:href='%23a' y='44'/%3e%3c/g%3e%3cpath stroke='%23fff' d='M0 17v10'/%3e%3ccircle r='12' fill='%23cd2e3a'/%3e%3cpath fill='%230047a0' d='M0-12A6 6 0 0 0 0 0a6 6 0 0 1 0 12 12 12 0 0 1 0-24z'/%3e%3c/g%3e%3cg transform='rotate(-123.69)'%3e%3cuse xlink:href='%23b'/%3e%3cpath stroke='%23fff' d='M0-23.5v3M0 17v3.5m0 3v3'/%3e%3c/g%3e%3c/svg%3e)
