Consecutive ruptures on a complex conjugate fault system during the 2018 Gulf of Alaska earthquake

2018年アラスカ湾地震の複雑な破壊過程を解析 --間欠的に加速・減速する奇妙な巨大地震--. 京都大学プレスリリース. 2021-03-22.We developed a flexible finite-fault inversion method for teleseismic P waveforms to obtain a detailed rupture process of a complex multiple-fault earthquake. We estimate the distribution of potency-rate density tensors on an assumed model plane to clarify rupture evolution processes, including variations of fault geometry. We applied our method to the 23 January 2018 Gulf of Alaska earthquake by representing slip on a projected horizontal model plane at a depth of 33.6 km to fit the distribution of aftershocks occurring within one week of the mainshock. The obtained source model, which successfully explained the complex teleseismic P waveforms, shows that the 2018 earthquake ruptured a conjugate system of N-S and E-W faults. The spatiotemporal rupture evolution indicates irregular rupture behavior involving a multiple-shock sequence, which is likely associated with discontinuities in the fault geometry that originated from E-W sea-floor fracture zones and N-S plate-bending faults

Nanopipette with a lipid nanotube as nanochannel

Proceedings of the 7th IEEE International Conference on Nanotechnology, August 2 - 5, 2007, Hong Kon

Role of PERK in mitochondrial function

Mitochondria play a central role in the function of brown adipocytes (BAs). Although mitochondrial biogenesis, which is indispensable for thermogenesis, is regulated by coordination between nuclear DNA transcription and mitochondrial DNA transcription, the molecular mechanisms of mitochondrial development during BA differentiation are largely unknown. Here, we show the importance of the ER-resident sensor PKR-like ER kinase (PERK) in the mitochondrial thermogenesis of brown adipose tissue. During BA differentiation, PERK is physiologically phosphorylated independently of the ER stress. This PERK phosphorylation induces transcriptional activation by GA-binding protein transcription factor α subunit (GABPα), which is required for mitochondrial inner membrane protein biogenesis, and this novel role of PERK is involved in maintaining the body temperatures of mice during cold exposure. Our findings demonstrate that mitochondrial development regulated by the PERK–GABPα axis is indispensable for thermogenesis in brown adipose tissue

In vivo expression of the HBZ gene of HTLV-1 correlates with proviral load, inflammatory markers and disease severity in HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP)

<p>Abstract</p> <p>Background</p> <p>Recently, human T-cell leukemia virus type 1 (HTLV-1) basic leucine zipper factor (HBZ), encoded from a minus strand mRNA was discovered and was suggested to play an important role in adult T cell leukemia (ATL) development. However, there have been no reports on the role of HBZ in patients with HTLV-1 associated inflammatory diseases.</p> <p>Results</p> <p>We quantified the HBZ and tax mRNA expression levels in peripheral blood from 56 HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) patients, 10 ATL patients, 38 healthy asymptomatic carriers (HCs) and 20 normal uninfected controls, as well as human leukemic T-cell lines and HTLV-1-infected T-cell lines, and the data were correlated with clinical parameters. The spliced HBZ gene was transcribed in all HTLV-1-infected individuals examined, whereas tax mRNA was not transcribed in significant numbers of subjects in the same groups. Although the amount of HBZ mRNA expression was highest in ATL, medium in HAM/TSP, and lowest in HCs, with statistical significance, neither tax nor the HBZ mRNA expression per HTLV-1-infected cell differed significantly between each clinical group. The HTLV-1 HBZ, but not tax mRNA load, positively correlated with disease severity and with neopterin concentration in the cerebrospinal fluid of HAM/TSP patients. Furthermore, HBZ mRNA expression per HTLV-1-infected cell was decreased after successful immunomodulatory treatment for HAM/TSP.</p> <p>Conclusion</p> <p>These findings suggest that <it>in vivo </it>expression of HBZ plays a role in HAM/TSP pathogenesis.</p

ヒガシ ニホン ダイシンサイ ヒサイチ ニ オケル ワカモノ ノ ライフコース ジョウケン コンナン チイキ デ セイカツ スル リユウ ト コミュニティ ノ フッコウ

本研究の目的は東日本大震災の被災地である過疎地域の若者の現状を描くことにある。東日本大震災の特徴のひとつは、被災地の多くが高齢化と人口減少の課題を抱えた過疎地域であった点にある。本研究が調査地とする宮城県南三陸町は震災において壊滅的な被害を受けた。その後、今日に至るまで人口流出は止まっていない。それでもなお、南三陸を居住地として選ぶ若者がいる。本研究では南三陸の若者のライフコースを分析することを通じて、条件困難地域における若者の生活と震災の影響を検討した。調査の結果、南三陸を生活の拠点に選んだ若者のライフコースは、U ターン型、I ターン/ 移住型、ローカル/ 県内周流型ごとに特徴が見られた。そして分析の結果、第１に、彼らの「幸福」は、本人の職業選択と地域コミュニティへの参加の程度にもよると考えられた。第２に、若者は「地域愛着」「人間関係」「自己実現（就労）」の3 つの理由から条件困難地域を居住地に選んでいることがわかった。そして第３に、若者は震災と無関係でいることはできず、震災からの復興の過程において、地域住民とのコミュニケーションを通して、今日的なコミュニティを形成する構成員となり、ソーシャルな課題と自己実現の両方に取り組んでいると考えられた。The purpose of this study is to analyze young people in the depopulated areas affected by the Great East Japan Earthquake. One of the characteristics of this disaster was that the affected areas had long been facing various social problems. Specifically, it was a depopulated area with issues of aging and declining population. Population decline became an even greater social problem as a result of the earthquake. The affected areas are facing serious population decline and aging, and young people are losing their bases of livelihood. Minamisanriku, Miyagi Prefecture, where this study was conducted, was devastated by the earthquake. To this day, the population outflow has not stopped. Despite these circumstances, there are young people who choose Minamisanriku as their place of residence. This study attempted to understand the factors that led young people to choose Minamisanriku as their place of residence, despite the region's declines. Through analyzing the life course of young people in Minamisanriku, we examined their lives in such a difficult area and the impact of the earthquake on them. The survey results show that the life course of young people who chose Minamisanriku as their base of living can be classified into three categories; U-turn type, who returned to Minamisanriku after once going to school or working in the city center. I-turn type who moved from urban areas to Minamisanriku. Local-type who have lived and worked in Minamisanriku since birth. First, the analysis revealed that their ”happiness” depends on their career choices and the degree of participation in the communities. Second, they chose Minamisanriku as their place of residence due to "community attachment," “human relations, ”and "self-actualization (employment)”. Third, young people cannot remain unrelated to the disaster, and in the process of recovery from the disaster, they become members of the community through communication with local residents, and they are considered to be tackling both social issues and self-actualization.論文RESEARCH ARTICL

Integrative Annotation of 21,037 Human Genes Validated by Full-Length cDNA Clones

The human genome sequence defines our inherent biological potential; the realization of the biology encoded therein requires knowledge of the function of each gene. Currently, our knowledge in this area is still limited. Several lines of investigation have been used to elucidate the structure and function of the genes in the human genome. Even so, gene prediction remains a difficult task, as the varieties of transcripts of a gene may vary to a great extent. We thus performed an exhaustive integrative characterization of 41,118 full-length cDNAs that capture the gene transcripts as complete functional cassettes, providing an unequivocal report of structural and functional diversity at the gene level. Our international collaboration has validated 21,037 human gene candidates by analysis of high-quality full-length cDNA clones through curation using unified criteria. This led to the identification of 5,155 new gene candidates. It also manifested the most reliable way to control the quality of the cDNA clones. We have developed a human gene database, called the H-Invitational Database (H-InvDB; http://www.h-invitational.jp/). It provides the following: integrative annotation of human genes, description of gene structures, details of novel alternative splicing isoforms, non-protein-coding RNAs, functional domains, subcellular localizations, metabolic pathways, predictions of protein three-dimensional structure, mapping of known single nucleotide polymorphisms (SNPs), identification of polymorphic microsatellite repeats within human genes, and comparative results with mouse full-length cDNAs. The H-InvDB analysis has shown that up to 4% of the human genome sequence (National Center for Biotechnology Information build 34 assembly) may contain misassembled or missing regions. We found that 6.5% of the human gene candidates (1,377 loci) did not have a good protein-coding open reading frame, of which 296 loci are strong candidates for non-protein-coding RNA genes. In addition, among 72,027 uniquely mapped SNPs and insertions/deletions localized within human genes, 13,215 nonsynonymous SNPs, 315 nonsense SNPs, and 452 indels occurred in coding regions. Together with 25 polymorphic microsatellite repeats present in coding regions, they may alter protein structure, causing phenotypic effects or resulting in disease. The H-InvDB platform represents a substantial contribution to resources needed for the exploration of human biology and pathology

Construction of fault geometry by finite-fault inversion of teleseismic data

Conventional seismic source inversion estimates the earthquake rupture process on an assumed fault plane that is determined a priori. It has been a difficult challenge to obtain the fault geometry together with the rupture process by seismic source inversion because of the nonlinearity of the inversion technique. In this study, we propose an inversion method to estimate the fault geometry and the rupture process of an earthquake from teleseismic P waveform data, through an elaboration of our previously published finite-fault inversion analysis (Shimizu et al. 2020). That method differs from conventional methods by representing slip on a fault plane with five basis double-couple components, expressed by potency density tensors, instead of two double-couple components compatible with the fault direction. Because the slip direction obtained from the potency density tensors should be compatible with the fault direction, we can obtain the fault geometry consistent with the rupture process. In practice we rely on an iterative process, first assuming a flat fault plane and then updating the fault geometry by using the information included in the obtained potency density tensors. In constructing a non-flat model-fault plane, we assume for simplicity that the fault direction changes only in either the strike or the dip direction. After checking the validity of the proposed method through synthetic tests, we applied it to the Mw 7.7 2013 Balochistan, Pakistan, and Mw 7.9 2015 Gorkha, Nepal, earthquakes, which occurred along geometrically complex fault systems. The modelled fault for the Balochistan earthquake is a curved strike-slip fault convex to the south-east, which is consistent with the observed surface ruptures. The modelled fault for the Gorkha earthquake is a reverse fault with a ramp-flat-ramp structure, which is also consistent with the fault geometry derived from geodetic and geological data. These results exhibit that the proposed method works well for constraining fault geometry of an earthquake

Development of an inversion method to estimate fault geometry from teleseismic data

Teleseismic waveforms contain information on fault slip evolution during an earthquake, as well as on the fault geometry. A linear finite-fault inversion method is a tool for solving the slip-rate function distribution under an assumption of fault geometry as a single or multiple-fault-plane model. An inappropriate assumption of fault geometry would tend to distort the solution due to Green's function modelling errors. We developed a new inversion method to extract information on fault geometry along with the slip-rate function from observed teleseismic waveforms. In this method, as in most previous studies, we assumed a flat fault plane, but we allowed arbitrary directions of slip not necessarily parallel to the assumed fault plane. More precisely, the method represents fault slip on the assumed fault by the superposition of five basis components of potency-density tensor, which can express arbitrary fault slip that occurs underground. We tested the developed method by applying it to real teleseismic P waveforms of the Mw 7.7 2013 Balochistan, Pakistan, earthquake, which is thought to have occurred along a curved fault system. The obtained spatiotemporal distribution of potency-density tensors showed that the focal mechanism at each source knot was dominated by a strike-slip component with successive strike angle rotation from 205° to 240° as the rupture propagated unilaterally towards the south-west from the epicentre. This result is consistent with Earth's surface deformation observed in optical satellite images. The success of the developed method is attributable to the fact that teleseismic body waves are not very sensitive to the spatial location of fault slip, whereas they are very sensitive to the direction of fault slip. The method may be a powerful tool to extract information on fault geometry along with the slip-rate function without requiring detailed assumptions about fault geometry