FOCAL MECHANISM OF VOLCANIC EARTHQUAKE OF THE VALCANO ASO

During the recent active period, from April 1965 to March 1966, of the Volcano Aso, a swarm of volcanic earthquakes was observed at the Hondo observation room of Kyoto University. By analysing the data, the locations of foci of volcanic earthquakes are determined and the focal mechanism is discussed. The main results obtained are as follows: (1) the distribution of foci of volcanic earthquakes is varied with the volcanic activity, that is, the foci are located in comparatively narrow region before the eruption, but scattered after the eruption; (2) the characteristic earthquakes regarded as a rarefaction type are found, that is, the initial phases are all "pull" around the epicenter. These rarefaction type earthquakes are observed in the earlier time and the active time, but not in the later time

MEASUREMENT OF KINETIC ENERGY OF VOLCANIC MICRO-TREMORS

An apparatus is prepared for the purpose of direct measurement of oscillatory energy. This digital energy accumulator, called DEA-1, enables us to obtain precise results more easily than hitherto. From its application to the measurement of micro-tremors at the Volcano Aso, it is concluded that the release of energy in the form of micro-tremors is about 10^12 ergs per day in the quiescent state. In addition, the variation in period of micro-tremors in relation to changes in volcanic activity can be detected by the use of DEA-1

A CHARACTERISTIC OCCURRENCE OF EARTHQUAKE SWAMS AT THE ASO CALDERA-RIM

Since the big explosion of October, 1965, at the Volcano Aso, the red-hot bottom in the 1st crater has been observed almost continuously during these several years. At the end of July, 1971, a small pit of 10 m in diameter opened at the bottom of crater and volcanic ash has been ejected intermittently from October, 1971, until now. Under such volcanic conditions, four groups of small earthquakes occurred at the western area of the Aso Caldera during the period from August, 1970, to .January, 1972. The results obtained are as follows: (1) The life of each swarm is shorter than about 40 hours and the foci are restricted to a small region. (2) The epicentral regions of the four swarms lie on a line along the northwestern rim of the caldera and the seismic region appears to be migrated successively from the south to the north. (3) The focal depths are 4-16 km under the Tateno Valley, only a collasped part of the caldera, and 4-8 km under the caldera-rim or the outer side of caldera. (4) The spa._es occupied by the swarms occurred under the caldera-rim or the collapsed part, spread vertically while those under the outer side of caldera spread horizontally. (5) The released energy of the swarm under the Tateno Valley amounted to 10^17 ergs, is smaller than the energies of the others, amounted to 10^18- 19 ergs. Therefore, it seems to reflect the tectonic state under the collapsed part of the caldera

Two-stage modeling of Strombolian-type eruptions and quantification of the model parameters: Insight from the seismic and acoustic signals

International audienceThe seismic signals of majority Strombolian explosions show a two-phase structure that may be the result of a two-stage explosive eruption. We quantify the parameters of two proposed stages of Strombolian eruptions at volcanoes Arenal, Aso and Yasur using 193 seismic records and 18 acoustic signals and considering that the first stage of eruption represents the seismically active process of the gas slug expansion and ascent (GSEA) in the conduit and the second stage is associated with the gas slug burst at the surface. It is shown that the radiated seismic energy of Strombolian explosions at volcanoes is strongly dependent on the seismic energy radiated during GSEA. The seismic energy of explosions is correlated also with the duration of GSEA process in the interval of durations between 1.3 and 3.7 s. For shorter GSEA durations, the correlation is absent. The acoustic energy of explosions is characterized by inverse dependence on the durations of GSEA. These results demonstrate the influence of the GSEA process on the surface manifestations of Strombolian explosions

Effect of ASP2151, a Herpesvirus Helicase-Primase Inhibitor, in a Guinea Pig Model of Genital Herpes

ASP2151 is a herpesvirus helicase-primase inhibitor with antiviral activity against varicella zoster virus and herpes simplex virus types 1 (HSV-1) and 2 (HSV-2). Here, we examined the potency and efficacy of ASP2151 against HSV in vitro and in vivo. We found that ASP2151 was more potent in inhibiting the replication of HSV-1 and HSV-2 in Vero cells in the plaque reduction assay and had greater anti-HSV activity in a guinea pig model of genital herpes than did acyclovir and valacyclovir (VACV), respectively. Oral ASP2151 given from the day of infection reduced peak and overall disease scores in a dose-dependent manner, resulting in complete prevention of symptoms at the dose of 30 mg/kg. The 50% effective dose (ED50) values for ASP2151 and VACV were 0.37 and 68 mg/kg, respectively, indicating that ASP2151 was 184-fold more potent than VACV. When ASP2151 was administered after the onset of symptoms, the disease course of genital herpes was suppressed more effectively than by VACV, with a significant reduction in disease score observed one day after starting ASP2151 at 30 mg/kg, whereas the therapeutic effect of VACV was only evident three days after treatment at the highest dose tested (300 mg/kg). This indicated that ASP2151 possesses a faster onset of action and wider therapeutic time window than VACV. Further, virus shedding from the genital mucosa was significantly reduced with ASP2151 at 10 and 30 mg/kg but not with VACV, even at 300 mg/kg. Taken together, our present findings demonstrated the superior potency and efficacy of ASP2151 against HSV

Self-organization of hepatocyte morphogenesis depending on the size of collagen microbeads relative to hepatocytes

Recent advances in microfabrication technologies have enabled us to construct collagen gel microbeads, which can be cultured with hepatocytes. However, little is known about the hepatocyte-collagen gel microbead interactions. Here, we aimed to clarify the effects of the balance between cell-cell and cell-collagen gel microbead interactions on hepatocyte morphogenesis and functions. The magnitude of cell-microbead interactions was controlled by changing the size of the microbeads, which were smaller than, comparable to, and larger than hepatocytes. These small, medium, and large microbeads were cultured separately with primary hepatocytes. Phase-contrast and time-lapse imaging revealed that the medium microbeads significantly induced the construction of 3D structures composed of the microbeads and hepatocytes in a self-organizing manner, whereas hepatocytes formed 2D monolayers with the small or large microbeads. These results suggest that only the medium microbeads induced the 3D tissue formation of hepatocytes. Furthermore, liver-specific functions, such as albumin secretion and ammonia clearance, were significantly upregulated in the 3D structures. These findings are critical to understand how to control the construction of 3D hepatocyte tissues with hydrogel microbeads in the context of biofabrication