Search

Promoting cell growth is demanded in various applications, such as drug screening and regenerative medicine. Recently, non-thermal atmospheric pressure plasma (NTAPP), which can generate reactive oxygen and nitrogen species under atmospheric conditions, has been used to promote cell growth. In this study, microperfusion systems using the stimulation of NTAPP exposure were developed to induce cell growth. NTAPP was generated through the dielectric barrier discharge method. When NTAPP exposure was applied to pure water for 4 min, concentrations of nitrate, nitrite, and hydrogen peroxide reached 250, 20, and 0.5 mg l−1, respectively. Further, C2C12 murine myoblast cells were injected into the microperfusion system, stimulated with NTAPP exposure, and cultured for 3 d. Then, the liquid medium was changed to initiate cell differentiation. The formation of tubular structures was observed after incubation for 3 d.

Particularly in the early stages of infection spread in spring 2020, mass infection to COVID-19 occurred mainly in densely populated areas. In order to control the spread of the disease while minimizing its impact on economic activities, response and awareness-raising were required not only at the national level but also at the prefectural level. In this study, we attempted to compare and verify the characteristics of the decision-making process and the effectiveness of the prefectural response by quantitatively evaluating the changes in the measures taken by each prefecture in Japan over time.

Thin films of AlN, AlGaN, and AlGaN-based device structures of approximately 1 cm2 formed on a sapphire substrate were successfully exfoliated from the substrate by immersion in heated (115 °C) and pressurized (170 kPa) water. These thin films were crystalline, grown on periodically formed AlN nanopillars. The water was permeated through intentional voids formed in the AlGaN or AlN crystalline layers by using periodic AlN nanopillars. The exfoliated AlGaN exhibited clear X-ray diffraction peaks from its (0002) plane diffraction. Transmission electron microscopy (TEM) confirmed that exfoliation introduced few additional dislocations and that the device structure was maintained.

We report two approaches of the fabrication techniques for three-dimensional patterning across vertical sidewalls based on the photolithography. One approach applies the techniques of spray coating the photoresist and the angled exposure. The supposed application is the microenergy source summing the voltage of silicon (Si) photo cells. Since Si photo cell islands on the buried oxide are isolated from each other, the output voltage is summed well without interacting with the common substrate. Wiring using the vertical sidewalls minimizes the shadow region caused by the metal electrode. Another approach introduces a new sheet, which consists of polyvinyl alcohol (PVA) and polyethylene terephthalate layers. The photoresist film is spin-coated and pasted on the substrate making the bridge over the trench. The pattern of the cantilever overhanging the trench is transferred. Then, PVA is dissolved in water and the resist is developed. When the rinse water dries, the cantilever bends and adheres on the vertical sidewall. The minimum pattern width designed is 10 μm and is obtained on the vertical sidewall.

A noninvasive sensor device is realized combined with microfluidic channel and optical fibers. The optical functions can be combined using the optical fiber. The bio-samples of cells in water is trapped being on the optical path. In addition to the transmission spectrum of the static signal, the time dependent response against the mechanical stimulation is measured.

d -Amino acids are important building blocks for various compounds, such as pharmaceuticals and agrochemicals. A more cost-effective enzymatic method for d -amino acid production is needed in the industry. We improved a one-pot enzymatic method for d -amino acid production by the dynamic kinetic resolution of N-succinyl amino acids using two enzymes: d -succinylase (DSA) from Cupriavidus sp. P4-10-C, which hydrolyzes N-succinyl- d -amino acids enantioselectively to their corresponding d -amino acid, and N-succinyl amino acid racemase (NSAR, EC.4.2.1.113) from Geobacillus stearothermophilus NCA1503. In this study, DSA and NSAR were purified and their properties were investigated. The optimum temperature of DSA was 50°C and it was stable up to 55°C. The optimum pH of DSA and NSAR was around 7.5. In d -phenylalanine production, the optical purity of product was improved to 91.6% ee from the examination about enzyme concentration. Moreover, 100 mM N-succinyl- dl -tryptophan was converted to d -tryptophan at 81.8% yield with 94.7% ee. This enzymatic method could be useful for the industrial production of various d -amino acids.