Expreriment of Seismic Failure of a Long Embankment

Seismic damage to long structures such as river dikes, fill-type dams, and road embankments has been sometimes found to take place at locally limited spot. Local failures of a long embankment during an earthquake are mainly due to heterogeneous ground condition. However there are some cases that local failures were took place even though the ground condition was homogeneous. One of the factors causing local failures under such conditions may be the three dimensional response of the embankment. In this paper, the typical failure of the Kushiro River dike is reported. This paper aims to clarify the influence of three-dimensional response to local failure in embankments. A series of shaking table tests was carried out. The results reveal that local failure can be caused by periodical three dimensional effects during shaking

Localization of Liv2 as an Immature Hepatocyte Marker in EB Outgrowth

The objective of this study was to establish Liv2, a surface marker of mouse immature hepatocytes (hepatoblasts), as a selection tool for embryonic stem (ES) cell–derived immature hepatocytes by acquiring basic data on Liv2 in normal mouse embryos and by confirming Liv2 expression in mouse ES-derived cells. The estimated molecular weight of Liv2 was 4045 kDa, and immunoreactivity was definitively detected in the cell membrane of fetal hepatocytes on embryonic day (E) 9.5, declined gradually until E12.5, and subsequently became undetectable. Liv2 was localized on and close to the cell membrane. Embryoid bodies (EB) were formed from mouse ES cells whose undifferentiated state was confirmed with immunostaining of Nanog by the hanging drop method. A few Liv2-positive cells occurred as a cluster in EB outgrowth on day 7, but only some of these were albumin (ALB)-positive on day 13. These cells had the same pattern of immunoreactivity, i.e., localization on the cell membrane, as immature hepatocytes in the developing liver, although there were other types of cells with a different pattern of immunoreactivity that were seen only as a granular pattern in the cytoplasm and without ALB or the neuronal marker nestin. These results suggest that Liv2 may be useful as a surface marker for immature hepatocytes derived from ES cells. This application would allow for the sole selection of immature hepatocytes and provide a useful tool for regenerative medicine

Hepatocyte Differentiation from Human ES Cells using the Simple Embryoid Body Formation Method and the Staged-Additional Cocktail

To induce hepatocytes from human embryonic stem (hES) cells easily and effectively, a simple suspension culture method that separates ES colonies with a scraper and transfers them into newly developed, nonadherent MPC (2-methacryloyloxyethyl phosphorylcholine) plates, and the staged-additional cocktail method, including growth factors, cytokines, and Lanford serum-free medium, were developed and evaluated mainly by morphological analysis. The formed embryoid bodies (EBs) showed compact cellular agglomeration until day 4 and later formed coeloms in their interior. RT-PCR (reverse transcriptase-polymerase chain reaction) analysis showed that they are gene markers of the three germ layers. Mesenchymal cells with rough endoplasmic reticulum (rER) and extracellular matrix (ECM), and without junctions, were recognized in the interior of the EBs by transmission electron microscopy (TEM) in addition to epithelial cells. When they were stimulated by the staged-additional cocktail, they expressed albumin-positive immunoreactivity, indocyanine green (ICG) uptake, and typical ultrastructures of the hepatocytes, including bile canaliculi. These results indicate that these combined methods promote EB formation and hepatocyte differentiation from hES cells

A Fundamental Survey on the Soil Properties in the Airport Embankments

The evaluation of seismic performance in the airport embankments is very important. However, there are many unclear points on the soil properties in the airport embankments. In this study, we investigated about ground characteristics by collecting the previous soil test data in the Japanese airport embankments. We summarized the relationship between the cohesion c and the internal friction angle φ. The results are useful for the evaluation of seismic performance in the airport embankments

A Fundamental Study on the Threshold Acceleration of Embankments during an Earthquake

At present, the Newmark Sliding Block Method is adopted as a seismic evaluation method of embankments in Japan. The threshold acceleration during shaking is supposed to be a constant in the Newmark Sliding Block Method. However, threshold acceleration can be varied during strong earthquake motions. In this study, several dynamic centrifuge model tests were carried out to investigate the threshold acceleration of embankments during the shaking. The compensation in the Newmark Sliding Block Method was proposed considering variations in threshold acceleration. The test data indicate that the threshold acceleration of the embankments has a tendency to decrease during an earthquake

A Proposal of a Practical Seismic Performance Evaluation Method for Slopes

Slope failures on a lifeline such as expressway were observed in Japan Mid Niigata earthquake 2004 and Noto Hanto earthquake 2007. However, it is not realistic to check the seismic performance of component of a lifeline. It is important how to pick up relatively weak section in terms of seismic resistance. In this study, a practical seismic evaluation method of slopes was proposed by reviewing previous studies by the authors. The proposed method enables a rational slope stability assessment of a lifeline

A Proposal on the Simple and Easy Method of Seismic Response Calculation of Embankments Considering Vertical Seismic Motion

Since the UD direction ground motions of the Hyogoken-nambu and Niigataken-chuetsu earthquakes were very large, it suffered the seismic damage that earth structures was very enormous. However, the effects which vertical seismic motion exerts on the destruction of embankment aren't taken sufficiently into account in the seismic design of the earth structures, So, in this study, the simple and easy calculation method of seismic response calculation that the vibration characteristics in the horizontal and vertical direction of embankments were taken into consideration at the same time is proposed. Then, the modified Newmark method that response characteristics in both directions of embankments were taken into consideration is proposed

Non-centralized and functionally localized nervous system of ophiuroids: evidence from topical anesthetic experiments

Ophiuroids locomote along the seafloor by coordinated rhythmic movements of multi-segmented arms. The mechanisms by which such coordinated movements are achieved are a focus of interest from the standpoints of neurobiology and robotics, because ophiuroids appear to lack a central nervous system that could exert centralized control over five arms. To explore the underlying mechanism of arm coordination, we examined the effects of selective anesthesia to various parts of the body of ophiuroids on locomotion. We observed the following: (1) anesthesia of the circumoral nerve ring completely blocked the initiation of locomotion; however, initiation of single arm movement, such as occurs during the retrieval of food, was unaffected, indicating that the inability to initiate locomotion was not due to the spread of the anesthetic agent. (2) During locomotion, the midsegments of the arms periodically made contact with the floor to elevate the disc. In contrast, the distal segments of the arms were pointed aborally and did not make contact with the floor. (3) When the midsegments of all arms were anesthetized, arm movements were rendered completely uncoordinated. In contrast, even when only one arm was left intact, inter-arm coordination was preserved. (4) Locomotion was unaffected by anesthesia of the distal arms. (5) A radial nerve block to the proximal region of an arm abolished coordination among the segments of that arm, rendering it motionless. These findings indicate that the circumoral nerve ring and radial nerves play different roles in intra- and inter-arm coordination in ophiuroids