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Infertility is often cited as one of the causes of a declining birthrate, which has become a serious social problem in recent years. Processes by which motile sperm can be safely and easily sorted are therefore important for infertility treatment. Therefore, as a new sorting method, microfluidic sperm sorter using the microfluidic system has been developed. To improve more separation efficiency of this device, it is necessary to know the behaviors of motile sperm in the microchannel where the sperm undergo shear flow. The previous study implied the necessity of the modeling of motile sperm in the shear flow. In the present study, therefore, we experimentally investigated the behavior of the motile sperm in the Taylor-Couette flow using PTV (Particle Tracking Velocimetry) method. The experimental results showed that the ascent of the shear stress led to the increase in the sperm velocity, and the direction of the sperm velocity was opposite to that of the flow.
The flowable latent heat storage material like Oil/Water type emulsion, microencapsulated latent heat material-water mixture or ice slurry, etc., is enabled to transport the latent heat in a pipe. Supercooling phenomenon of the dispersed latent heat storage material in continuous phase is obstructed by a latent heat storage. The latent heat storage rates of dispersed waterdrops in W/O (Water/Oil) emulsion are investigated experimentally in this study. The waterdrops in emulsion have the diameter within 3 - 25 μm, the averaged diameter of waterdrops is 7.3 μm and the standard deviation is 2.9 μm. Supercooling release of waterdrops in emulsion is examined by short time impressing of the ultrasonic. The direct contact heat exchange method is chosen as the phase change rate evaluation of waterdrops in W/O emulsion. The supercooled temperature is set as parameters of this study. The previous obtained experimental result, as the condition without impressing ultrasonic wave, showed that the 35 K or more degree from melting point brings 100% latent heat storage rate of W/O emulsion. It is clarified that it is possible to reduce 20 K of supercooling degree by impressing the ultrasonic.
The vaccination of one person may prevent another from becoming
infected, either because the vaccine may prevent the first person from
acquiring the infection and thereby reduce the probability of transmission to
the second, or because, if the first person is infected, the vaccine may impair
the ability of the infectious agent to initiate new infections. The former
mechanism is referred as a contagion effect and the latter is referred as an
infectiousness effect. By applying a principal stratification approach, the
conditional infectiousness effect has been defined, but the contagion effect is
not defined using this approach. Recently, new definitions of unconditional
infectiousness and contagion effects were provided by applying a mediation
analysis approach. In addition, a simple relationship between conditional and
unconditional infectiousness effects was found under a number of assumptions.
These two infectiousness effects can be assessed by very simple estimation and
sensitivity analysis methods under the assumptions. Nevertheless, such simple
methods to assess the contagion effect have not been discussed. In this paper,
we review the methods of assessing infectiousness effects, and apply them to
the inference of the contagion effect. The methods provided here are
illustrated with hypothetical vaccine trial data.