Niigata College of Technology

Abstract The Deci-hertz Interferometer Gravitational Wave Observatory (DECIGO) is a future Japanese space mission with a frequency band of 0.1 Hz to 10 Hz. DECIGO aims at the detection of primordial gravitational waves, which could have been produced during the inflationary period right after the birth of the Universe. There are many other scientific objectives of DECIGO, including the direct measurement of the acceleration of the expansion of the Universe, and reliable and accurate predictions of the timing and locations of neutron star/black hole binary coalescences. DECIGO consists of four clusters of observatories placed in heliocentric orbit. Each cluster consists of three spacecraft, which form three Fabry–Pérot Michelson interferometers with an arm length of 1000 km. Three DECIGO clusters will be placed far from each other, and the fourth will be placed in the same position as one of the other three to obtain correlation signals for the detection of primordial gravitational waves. We plan to launch B-DECIGO, which is a scientific pathfinder for DECIGO, before DECIGO in the 2030s to demonstrate the technologies required for DECIGO, as well as to obtain fruitful scientific results to further expand multi-messenger astronomy.

Lip closing functions have never been evaluated from the viewpoint of elastic properties. The purpose of the present study was to investigate the behavior of the lower orbicularis oris muscle during a button-pull exercise to measure lip closing force and quantitatively evaluate its elastic properties using sonographic elastography. Appropriate compression loads for elastography were randomly measured on one of three types of acoustic couplers on three examiners. Compression tests were performed on three types of acoustic couplers within the appropriate compression load. Using the acoustic coupler with the lowest elastic modulus, the strain ratio of the lower orbicularis oris muscle during lip closing was measured, and elastography was performed on six males under tension loads of 0-8N. The intraclass correlation coefficient (1, 3) for the tension load of 0 N was 0.81. Elastography showed that the strain ratio values increased significantly (p < 0.05) as the tension load increased. Combining the data obtained from lip closing test devices and sonographic elastography enabled the muscle performance to be evaluated objectively and accurately.

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Deci-hertz Interferometer Gravitational Wave Observatory (DECIGO) is the future Japanese space mission with a frequency band of 0.1 Hz to 10 Hz. DECIGO aims at the detection of primordial gravitational waves, which could be produced during the inflationary period right after the birth of the universe. There are many other scientific objectives of DECIGO, including the direct measurement of the acceleration of the expansion of the universe, and reliable and accurate predictions of the timing and locations of neutron star/black hole binary coalescences. DECIGO consists of four clusters of observatories placed in the heliocentric orbit. Each cluster consists of three spacecraft, which form three Fabry-Perot Michelson interferometers with an arm length of 1,000 km. Three clusters of DECIGO will be placed far from each other, and the fourth cluster will be placed in the same position as one of the three clusters to obtain the correlation signals for the detection of the primordial gravitational waves. We plan to launch B-DECIGO, which is a scientific pathfinder of DECIGO, before DECIGO in the 2030s to demonstrate the technologies required for DECIGO, as well as to obtain fruitful scientific results to further expand the multi-messenger astronomy.

The tyrosinase 2 gene (tyr2) from two compatible strains of Grifola frondosa, the albino-type monokaryon strain IM-WM1-25 and the wild-type monokaryon strain IM-BM11-P21, were amplified and characterized (designated tyr2−Δ25 and tyr2+, respectively). A single base deletion in the coding region of tyr2−Δ25 from IM-WM1-25 was discovered, and this mutation is predicted to cause a frame-shift in translation, yielding inactive protein tyrosinase protein 2 (TYR2). Polymerase chain reaction (PCR) primer pairs were designed to detect normal tyr2+ and mutant tyr2−Δ25, and then the tyr2 genotype of F1 progenies, which was obtained from basidiospore isolation of IM-BM11-P21 × IM-WM1-25 (tyr+ × tyr2−Δ25) strain, was analyzed. Back-crossing (F1 progenies × IM-WM1-25) was performed and fruiting body colors of the crossed strains were analyzed. The fruiting bodies of all crossed strains were white and beige, and the corresponding genotypes were tyr2−Δ25 × tyr2−Δ25 and tyr+ × tyr2−Δ25. These results suggest that the causal gene of the albino mutation is tyr2 and this study provides a new strategy for the breeding of albino mushrooms belonging to G. frondosa.

Micro-fluid mechanics is an important area of research in modern fluid mechanics because of its many potential industrial and biological applications. However, the field is not fully understood yet. In previous work, when passing ultrapure water (UPW) in which air was dissolved (UPW*) through micro-orifices, we found that the flow velocity decreased and stopped over time, and membranes were frequently formed in the orifice when the flow stopped. The membrane came from the dissolved air in UPW*, and membrane formation was closely related to electric charges generated in orifices by the flow. In the present paper, we clarified the components of the membrane and suggested a mechanism for membrane formation. We examined the effect of contaminants on the membrane formation and confirmed our previous results. We identified the chemical components of the membrane and those present in the UPW* itself by using an electron probe microanalyzer and found that the proportion of each element differed between the membrane and UPW*. Raman and infrared (IR) spectroscopy showed that the membrane consisted of organic substances such as carotenoids, amides, esters, and sugars. We irradiated UPW* with ultraviolet light to cut organic chains that may be left in UPW* as contaminants. We found a similar membrane and organic compounds as in nonirradiated UPW*. Furthermore, although the UPW that was kept from contact with air after it was supplied from the UPW maker (UPW0) and bubbled with Ar gas (UPW0 bubbled with Ar) formed no membrane, the UPW0 bubbled with CO2 formed thin membranes, and Raman and IR analysis showed that this membrane contained carboxylic acid salts, carotenoids, or a mixture of both. We found that electric grounding of the orifice reduces the probability of membrane formation and that the jets issuing from an aperture bear negative charges, and we assumed that the micro-orifices possess positive charges generated by flows. Consequently, we suggest that organic compounds are synthesized from nonorganic matter in air or CO2 dissolved in water by the action of hydroxyl radicals generated by flows through micro-orifices.

Fluid mechanics at a very small scale, particularly micro-flows and nano-flows, have many technical applications, and the elastic properties of small-scale flows are strongly expressed even for dilute aqueous solutions of non-Newtonian fluids. We have investigated the flow properties of water and several types of surfactant solutions with spherical or rod-like micelles. Before the flow property investigations, Newtonian and non-Newtonian viscosities for the test fluids were observed by using a capillary viscosity meter. Pressure drops were experimentally measured, and the frictional coefficient of the pipe was estimated in flows through capillaries ranging from 133 $$\upmu $$ m to 2.87 mm in diameter. For water flow, good agreement was obtained between the experimental results and the predictions for Hagen–Poiseuille flow and the Blasius expression. The flow properties of the spherical micelle surfactant solutions agreed with those of water. However, the rod-like micelle surfactant solutions maintained laminar flows in the transition regions. Thus, a pseudo-laminarization effect for surfactant solutions with rod-like micelles is indicated. A relationship between these experimental results and estimated first normal stress differences is also strongly suggested.

Single crystals of ZrTr2Zn20 (Tr = Mn, Co, Ru) with a cubic CeCr2Al20-type structure (space group Fd-3m) were grown by a Zn-flux method. Electrical resistivity ρ(T) of ZrTr2Zn20 shows typical metallic behavior with the residual resistivity ratio (RRR) of 1.1 (Mn), 8.4 (Co) and 10 (Ru). Magnetic susceptibility χ(T) of ZrRu2Zn20 shows large diamagnetism. χ(T) of ZrTr2Zn20 (Tr = Mn, Co) clearly shows Curie-Weiss behavior, indicating that Mn/Co spins are really active as local magnetic moments or that a large spin fluctuation exists. χ(T) of ZrMn2Zn20 increases ferromagnetically at around 20 K. Because the anti-ferromagnetic correlation with active localized spins exists in ZrCo2Zn20, geometrical frustration of the pyrochlore lattice of Co is expected. However, specific heat C(T) of ZrCo2Zn20 shows no upturn at low temperatures and Sommerfeld coefficient γ is evaluated to be 24.8 mJ/(mol K2). We consider that the localized Co spins are insufficient to cause anomaly originated from the geometrical frustration, or the Co spins exist in a disordered arrangement of excess Co.

The pressure drops were measured for water, microbubble/water mixtures, and complex fluids (spherical micelle surfactant solution and polymer solution) in flows through micro-apertures (micro-orifices, circular pores, and hexagonal pores). For water, agreement between the resultant pressure drops and the predictions of the Navier-Stokes equation was obtained. For microbubble/water mixtures, drag reduction effect was suggested over a Reynolds number of about 1.0 × 101 in micro-orifice flows. Surfactant solutions exhibited the same results as microbubble/water mixtures. For polymer solutions, significant drag reduction was shown. Moreover, a drag reduction effect, which was independent of the used test fluids, was observed for Reynolds numbers over 1.0 × 101 in the flow through circular pores and hexagonal pores. To explain this phenomenon, the size effect, visco-elastic property, electric interaction, and interfacial tension are considered. The results suggest that electric interaction at the wall (interfacial tension) is a contributing factor. In addition, drag reduction rates were estimated.

The magnetic susceptibilities χ of liquid Ti–Sn and V–Sn alloys on the Sn-rich side have only a weak and positive temperature dependence, which suggests that Ti and V ions in the alloys are in the nonmagnetic state. Similarly, the χ values for liquid Co–Sn and Ni–Sn on the Sn-rich side are also in the nonmagnetic state. The data for nonmagnetic states can be analyzed using the Anderson model. Liquid Cr1−cSnc with c ≥ 0.5 and Mn1−cSnc with c ≥ 0.1 obey the Curie–Weiss law with regard to the dependence of χ on temperature. The χ for liquid Fe–Sn, Co1−cSnc with c ≤ 0.5, and Ni1−cSnc with c ≤ 0.1 also exhibited Curie–Weiss behavior. The compositional dependence of the χ for liquid alloys has a maximum at 50 at. % Cr for Cr–Sn, 70 at. % Mn for Mn–Sn, and 90 at. % Fe for Fe–Sn. In the present work, the compositional dependence of χ3d due to 3d electrons was compared for liquid binary transition metal–metal (TM–M; M = Sn, Ge, Si) alloys restricted to the M of tetravalent liquid metals. We found the inverse correlation of the magnitude of χ3d with the Fermi level EF, obtained at a composition of 50 at. % TM for liquid binary TM–M alloys.