Rigid and Flexible Retaining Walls During Kobe Earthquake

An overview is presented on seismic performance of rigid and flexible retaining walls based on case histories during earthquakes, notably from the 1995 Kobe earthquake. Three critical issues are discussed out of these case histories: (l) If the effects of an earthquake motion are approximated in terms of a pseudo-static inertia force using the Mononobe-Okabe equation, the equivalent seismic coefficient for evaluating gross stability of retaining walls should be less than 100 %, about 60 % on average, of a peak ground acceleration specified as a fraction of gravity (amax/g); (2) Liquefaction or excess pore water pressure increase in the subsoil seriously affects the retaining walls at waterfront, often resulting in excessively large displacements. Collapse of the wall, however, is rare. More attention should be directed toward identifying the mode and mechanism of displacements/failure of the retaining walls at the waterfront; (3) The order of the displacements of the walls at waterfront, ranging from 5 to 50% of the wall height, are summarized in a tentative list, classified by the structural type of walls, the level of earthquake shaking, and the extent of liquefaction

Effective Stress Analysis of a Sheet Pile Quaywall

In 1983, Nihonkai Chubu Earthquake of magnitude 7.7 hit northern part of Japan. The earthquake caused damage to quaywalls at Akita Port located about 100 km from the epicenter. The damage was associated with the liquefaction of backfill sand. In order to analyze the mechanism of the damage, soils are taken from the site for laboratory tests. The record of the earthquake motion is digitized. Based on these investigations, a two dimensional effective stress analysis is conducted. The model used in this study consists of a multiple virtual simple shear mechanisms oriented in arbitrary directions. The results of the effective stress analysis indicate that a fundamental mechanism in producing deformation of the soil and the structure is due to the initial stress and its release in accordance with the progress of cyclic mobility. This mechanism of deformation is quite different from that indicated by the conventional Newmark\u27s sliding block concept

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Human Fibroblast Sheet Promotes Human Pancreatic Islet Survival and Function In Vitro

In previous work, we engineered functional cell sheets using bone marrow-derived mesenchymal stem cells (BM-MSCs) to promote islet graft survival. In the present study, we hypothesized that a cell sheet using dermal fibroblasts could be an alternative to MSCs, and then we aimed to evaluate the effects of this cell sheet on the functional viability of human islets. Fibroblast sheets were fabricated using temperature-responsive culture dishes. Human islets were seeded onto fibroblast sheets. The efficacy of the fibroblast sheets was evaluated by dividing islets into three groups: the islets-alone group, the coculture with fibroblasts group, and the islet culture on fibroblast sheet group. The ultrastructure of the islets cultured on each fibroblast sheet was examined by electron microscopy. The fibroblast sheet expression of fibronectin (as a component of the extracellular matrix) was quantified by Western blotting. After 3 days of culture, islet viabilities were 70.2 ± 9.8%, 87.4 ± 5.8%, and 88.6 ± 4.5%, and survival rates were 60.3 ± 6.8%, 65.3 ± 3.0%, and 75.8 ± 5.6%, respectively. Insulin secretions in response to high-glucose stimulation were 5.1 ± 1.6, 9.4 ± 3.8, and 23.5 ± 12.4 μIU/islet, and interleukin-6 (IL-6) secretions were 3.0 ± 0.7, 5.1 ± 1.2, and 7.3 ± 1.0 ng/day, respectively. Islets were found to incorporate into the fibroblast sheets while maintaining a three-dimensional structure and well-preserved extracellular matrix. The fibroblast sheets exhibited a higher expression of fibronectin compared to fibroblasts alone. In conclusion, human dermal fibroblast sheets fabricated by tissue-engineering techniques could provide an optimal substrate for human islets, as a source of cytokines and extracellular matrix