Feasibility of Standardized Ejecta Evaluation for Spacecraft Surface Materials

Although a large spacecraft such as the International Space Station and other artificial satellites are thriving in the space environment due to the remarkable progress in the space development sector, their collisions with space debris are a growing concern. To examine the impact proof performance of spacecraft to space debris, hypervelocity impact experiments using a two-stage light gas gun and so on are necessary. However, space debris impact experiments are conducted in different manners dependent on the countries and the facilities. Therefore direct comparisons of the experimental results among different facilities are often difficult from the same viewpoint. In this study, the authors aim at assessment of international standardization of the hypervelocity impact experiments procedure. Projectiles with a diameter of 1 mm were used to simulate space debris impacting a target at 5 km/s. Copper witness plates were used to catch the secondary debris, namely ejecta, generated during the experiments. The size distributions of diameter of craters made by ejecta were measured on the witness plates, and they are compared one another among a solar array coupon, CFRP honeycomb and Aluminum honeycomb.2012 Hypervelocity Impact Symposium (HVIS 2012), September 16-20, 2012, Baltimore, Marylan

Radiation dose during relativistic electron precipitation events at the International Space Station

AbstractWe provide a quantitative estimate of the radiation dose during relativistic electron precipitation (REP) events at the International Space Station (ISS). To this goal, we take advantage of the data collected by the CALorimetric Electron Telescope, the Monitor of All‐sky X‐ray Image, and the Space Environment Data Acquisition equipment‐Attached Payload. The three ISS detectors offer complementary REP observations, including energy spectra and flux directional information, during a period of approximately 2.5 years, from November 2015 to March 2018. We have identified 762 REP events during this period from which we obtain the distribution of radiation dose, relevant to extravehicular activities outside the ISS

A Functional SNP in BNC2 Is Associated with Adolescent Idiopathic Scoliosis

Adolescent idiopathic scoliosis (AIS) is the most common spinal deformity. We previously conducted a genome-wide association study (GWAS) and detected two loci associated with AIS. To identify additional loci, we extended our GWAS by increasing the number of cohorts (2,109 affected subjects and 11,140 control subjects in total) and conducting a whole-genome imputation. Through the extended GWAS and replication studies using independent Japanese and Chinese populations, we identified a susceptibility locus on chromosome 9p22.2 (p = 2.46 × 10−13; odds ratio = 1.21). The most significantly associated SNPs were in intron 3 of BNC2, which encodes a zinc finger transcription factor, basonuclin-2. Expression quantitative trait loci data suggested that the associated SNPs have the potential to regulate the BNC2 transcriptional activity and that the susceptibility alleles increase BNC2 expression. We identified a functional SNP, rs10738445 in BNC2, whose susceptibility allele showed both higher binding to a transcription factor, YY1 (yin and yang 1), and higher BNC2 enhancer activity than the non-susceptibility allele. BNC2 overexpression produced body curvature in developing zebrafish in a gene-dosage-dependent manner. Our results suggest that increased BNC2 expression is implicated in the etiology of AIS

<所内学術研究成果報告>Q. 「海洋生物の医薬資源開-医薬を指向した海洋生物の探索と調査・開発」

約100万種といわれる海洋生物は,地上における最も未知の世界である。この海洋生物から,医薬資源となりうる有用な生理活性物質を発見し,構造を明らかにし,生理活性を検討することを目的としている。NIHで臨床試験中のドラスタチン10(ウミウシ成分)とブリオスタチン1(フサコケムシ成分)は,釡野がその研究に携わったものである。平成元年以来,日野,西川等の協力を得て,平塚付近(相模湾)および岩手県大槌町付近(大槌湾)の海洋生物を検討し,特に青森,浅虫湾のフサコケムシからブリオスタチン10という強い抗癌性物質を見いだし,抗エイズ活性もあることが分かった。また,これらの物質には,ホルモン産生活性などの作用の存在も明らかになり,医薬品としての開発の可能性が考えられる。さらに,フロリダ産コケムシから10数種の新規アルカロイドを単離したが,このうちconvolutamydineが,ヒト急性骨髄性白血病細胞HL-60に対し,強力な分化誘導作用を示し,新たな抗癌剤発見の手がかりになる可能性もある。2000年度には,ほぼこれらのアルカロイドの全合成を完成した。これらの結果をふまえ,日本沿岸およびアジア各地の海洋生物について探索が計画されている。さらに,橋本,三浦等が「しんかい6500」,「しんかい2000」により採集した深海生物に対する検討も行い,今までに相模湾産シロウリガイとヘイトウシンカイヒバリガイおよびサツマハオリムシ,さらに巻き貝2種Alyinconcha cf. hesseleriおよびIfremeria nautileiの化学成分の検討を行っている。また,竹内等による南極付近の生物の入手も期待できる現状にある。さらに,新しく速水先生が加わり,洞窟生物の調査・採集が可能となっている。一方,生理活性,薬理作用検討に新たにそれぞれ小宮山博士,林博士,川村教授の協力が得られている。また,一昨年から中国でのフサコケムシの探索が姚新生教授と新たに参加した易楊貨教授によって開始され,かなり大量の生物が採集された。この生物からの活性物質の単離はこれからの大きな仕事であり,その結果が期待される。本年度は今までの生物成分のまとめを行った。特に,日本産ナマコ類成分,沖縄と真鶴で採集した日本産フサコケムシ成分,および深海巻貝2種の成分研究を完成した

Evidence of causality of low body mass index on risk of adolescent idiopathic scoliosis: a Mendelian randomization study

IntroductionAdolescent idiopathic scoliosis (AIS) is a disorder with a three-dimensional spinal deformity and is a common disease affecting 1-5% of adolescents. AIS is also known as a complex disease involved in environmental and genetic factors. A relation between AIS and body mass index (BMI) has been epidemiologically and genetically suggested. However, the causal relationship between AIS and BMI remains to be elucidated.Material and methodsMendelian randomization (MR) analysis was performed using summary statistics from genome-wide association studies (GWASs) of AIS (Japanese cohort, 5,327 cases, 73,884 controls; US cohort: 1,468 cases, 20,158 controls) and BMI (Biobank Japan: 173430 individual; meta-analysis of genetic investigation of anthropometric traits and UK Biobank: 806334 individuals; European Children cohort: 39620 individuals; Population Architecture using Genomics and Epidemiology: 49335 individuals). In MR analyses evaluating the effect of BMI on AIS, the association between BMI and AIS summary statistics was evaluated using the inverse-variance weighted (IVW) method, weighted median method, and Egger regression (MR-Egger) methods in Japanese.ResultsSignificant causality of genetically decreased BMI on risk of AIS was estimated: IVW method (Estimate (beta) [SE] = -0.56 [0.16], p = 1.8 × 10-3), weighted median method (beta = -0.56 [0.18], p = 8.5 × 10-3) and MR-Egger method (beta = -1.50 [0.43], p = 4.7 × 10-3), respectively. Consistent results were also observed when using the US AIS summary statistic in three MR methods; however, no significant causality was observed when evaluating the effect of AIS on BMI.ConclusionsOur Mendelian randomization analysis using large studies of AIS and GWAS for BMI summary statistics revealed that genetic variants contributing to low BMI have a causal effect on the onset of AIS. This result was consistent with those of epidemiological studies and would contribute to the early detection of AIS