Yukihiro Yonemoto

Onionin A inhibits ovarian cancer progression by suppressing cancer cell proliferation and the protumour function of macrophages

It is well known that tumour-associated macrophages (TAMs) play an important role in tumour development by modulating the tumour microenvironment, and targeting of protumour activation or the M2 polarization of TAMs is expected to be an effective therapy for cancer patients. We previously demonstrated that onionin A (ONA), a natural low molecular weight compound isolated from onions, has an inhibitory effect on M2 macrophage polarization. In the present study, we investigated whether ONA had a therapeutic anti-ovarian cancer effect using in vitro and in vivo studies. We found that ONA reduced the extent of ovarian cancer cell proliferation induced by co-culture with human macrophages. In addition, we also found that ONA directly suppressed cancer cell proliferation. A combinatorial effect with ONA and anti-cancer drugs was also observed. The activation of signal transducer and activator of transcription 3 (STAT3), which is involved in cell proliferation and chemo-resistance, was significantly abrogated by ONA in ovarian cancer cells. Furthermore, the administration of ONA suppressed cancer progression and prolonged the survival time in a murine ovarian cancer model under single and combined treatment conditions. Thus, ONA is considered useful for the additional treatment of patients with ovarian cancer owing to its suppression of the protumour activation of TAMs and direct cytotoxicity against cancer cells.

Analytical consideration of liquid droplet impingement on solid surfaces

In industrial applications involving spray-cooling, combustion, and so on, prediction of the maximum spreading diameter of a droplet impinging on a solid surface permits a quantitative estimation of heat removal and energy consumption. However, although there are many experimental studies regarding droplet impingement behaviour, theoretical models have an applicability limit for predicting the maximum spreading diameter. In the present study, we have developed an analytical model for droplet impingement based on energy conservation that considers adhesion energy in both horizontal and vertical directions at the contact line. The theory is validated by our experiment and existing experimental data possessing a wide range of Weber numbers. We demonstrate that our model can predict βm (i.e., the maximum spreading diameter normalised in terms of initial droplet diameter) for various Newtonian liquids ranging from micro- to millimetre-sized droplets on different solid surfaces and can determine the transition between capillary and viscous regimes. Furthermore, theoretical relations for scaling laws observed by many researchers are derived.

Surface Wettability Effects on Flow Characteristics in Gas-liquid Two-phase Flow through Rectangular Horizontal Micro-channel

Experiments for gas-liquid two-phase flow in a horizontal rectangular micro-channel were conducted. The channel with rectangular cross-section of 1.0 mm height 1.0 mm width was used as the test channel. In order to understand the effects of wettability on the two-phase flows in the micro-channel, the channel wall near gas and liquid mixer was coated by a hydrophobic agent. The contact angles were approximately 80 for the non-coating surface (hydrophilic) and 127 for the coating one (hydrophobic). In the experiments, flow pattern, bubble length, bubble velocity, void fraction and pressure drop were measured. From the comparison of the measured parameters between coating and non-coating cases, the hydrophobic surface (coating surface) makes bubble length longer. Then, the longer bubble reduces pressure drop.

Measurement of cell mechanical properties by cell compression microdevice

This paper presents a measurement method for Youngs modulus of cells using fabricated microdevice. This presented method is based on two processes. A first step is cell compressive experiment using fabricated microdevice. The second step is a theoretical calculation for comparing with the experimental results. Cell compression microdevice was designed for controlling the magnitude of pressure to cells. The device consists of microchannels, cell culture chambers, and a diaphragm on the culture chamber for applying pressure to cells. The cells are directly compressed from the diaphragm above the cell culture chamber. The cell strain amount to the applied pressure was measured in the cell compressive experiment. Based on the experimental results, the Youngs modulus of cell was determined. The results obtained on Youngs modulus measurement of cells are comparatively similar to previously measured values by other researchers.