238 research outputs found

    Detection Curb

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    γ線照射処理した Picea abies の仮道管壁の構造

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    When a wood specimen (Picea abies (L.) KARST) was γ-irradiated (655 Mrad), microfibrillar texture as seen in the untreated wood was still clearly observed by replica on the surface of the tracheid, while this wood became non-crystalline with X-ray diffractioIn. In transverse and longitudinal sections of the tracheid in γ-irradiated wood microfibrils were observed by the method of block negative staining with uranyl acetate. The disintegration of γ-irradated wood produced many short broken microfibrils. The above facts indicate that γ-irradiation produces many defects even within the crystalline region of microfibrils while retaining their original shapeγ線照射 (655 Mrad) 処理材 〔Picea abies (L.) KARST〕 のX線回折図では結晶性ピークを示さないのに, 電子顕微鏡でレプリカ法により観察すると, 仮道管内壁面には顕著なミクロフィブリルの配向がみられた。本報では, γ線処理材の仮道管にみられるこのようなミクロフィブリル像の実体を明らかにしようとした。γ線処理材を酢酸ウラニルでブロック負染色法により電子顕微鏡観察すると, 仮道管の横断面・縦断面ともにミクロフィブリルが白い斑点状 或いは線状に存在することが確認された。さらにこの試料を解体して観察すると, 短破片状のミクロフィブリルがみられた。以上の結果から, このγ線処理材においては, ミクロフィブリル中に多くの結晶欠陥が存在するが, なおミクロフィブリルの形態は保持されているものと推定される

    ポプラ二次師部における多室結晶細胞の壁の発達

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    Cell wall development of chambered crystalliferous cells in the secondary phloem of Populus euramericana is described. These cells were differentiated from parenchyma strands which contacted with phloem fiber groups. A crystal was formed in a vacuole surrounded by tonoplast in each chamber. Then, the secondary wall deposition of chambered crystalliferous cells began only at the part adjacent to phloem fibers forming a protruding fringe which encircled the crystal. When the vacuole disappeared, the crystal had been surrounded by the wall substance on all sides except that away from the fiber. The wall on the crystal surface was not formed by the growth of any protrusion of the secondary wall, but formed independently by the deposition of wall substance on the crystal surface. The secondary wall development was completed after filling up the space between the crystal-surface wall and the thickened side wall adjacent to phloem fiber with newly deposited wall. The crystal-surface wall must be deposited after the tonoplast surrounding the crystal is converted into the plasma membrane多室結晶細胞は分化中の師部繊維に接する柔細胞ストランドから分化した。結晶は最初液胞中に認められた。師部繊維が二次壁の堆積を始める頃, 結晶細胞壁の師部繊維側の部分で二次壁形成が始まり, 結晶を取巻くように壁の突出部が形成された。結晶を取囲む液胞が見えなくなると, 師部繊維と反対側の面を除きすべての結晶表面に壁の堆積が起こった。しかし, この壁は結晶細胞の壁の突出部が張出してきて結晶表面を被ったものではなかった。最後に結晶表面の壁と結晶細胞の師部繊維側に堆積した二次壁との間が, 新たに堆積してきた壁物質によって埋められ, 結晶は厚い細胞壁中に取込まれた状態となる。結晶表面の壁は, 結晶を取囲んでいた液胞膜が原形質膜に置換えられた後に形成されたものと考えられる

    Mineralogical studies of lunar meteorite Yamato-793169, a mare basalt

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    A preliminary mineralogical study of the lunar meteorites Yamato (Y)-793169 and Asuka (A)-881757,which were apparently derived from a mare region of the Moon, has been performed to identify crystallization trends of their pyroxenes. Y-793169 is a crystalline basalt with similar basaltic components to lunar breccias EET87521 and Y-793274,containing strongly zoned Fe-Ca-rich pyroxenes. Their zoning trends in the pyroxene quadrilateral are closest to those found in the basaltic clast in an Apollo 16 breccia. Differentiation trends expressed by Ti/(Ti+Cr) versus Fe/(Fe+Mg) of Y-793169 and A-881757 pyroxenes are similar but they differ from those of EET87521. The Y-793169 trend starts at a more Mg-rich composition point than the A-881757 trend. Based on differences in textures and ranges of zoning trends, the pyroxene of A-881757 could represent growth deeper in the lava unit under conditions more closely approaching equilibrium, than Y-793169,which appears to have formed from a lava flow of similar bulk composition. Although Y-793169 has been described as the VLT basalt, some mesostases contain significant amounts of ilmenite and ulvospinel, together with fayalite, troilite, chromite and a silica mineral. Mg-rich pyroxenes as found in Y-793274 and EET87521 are not present in Y-793169 and A-881757 basalts

    Mineralogy of Yamato-791192, HED breccia and relationship between cumulate eucrites and ordinary eucrites

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    Cumulate eucrites and noncumulate (ordinary) eucrites are considered to have come from one (or similar) parent body and to have formed the crust of the Vesta-like asteroid. However, their relationship is not well established as to whether they have crystallized in a different magma or have differentiated within the same magma. We studied mineralogically Yamato-791192,which is a unique HED breccia with abundant cumulate eucrite and a rare ordinary eucrite clasts. The characteristics of pyroxene suggest that the polymict breccia was generated by gathering locally ordinary eucrites and cumulate eucrites. On the other hand, the Fe/Mg distribution shows that the liquid coexisting with most cumulate eucrites was too Fe-rich (mg [=Mg/ (Mg+Fe) atomic ratio]=0.25-0.30) to have crystallized as ordinary eucrites (mg=0.35-0.40). We also applied the liquid trapping model of fractional crystallization and calculate the change of mg of liquid and solid during fractional crystallization. This calculation suggests that if the cumulates include a large amount of residual liquid (40-50%), a cumulate eucrite (mg=0.50-0.55) could crystallize from ordinary eucritic liquid (mg=0.35-0.40). In conclusion, cumulate eucrites probably crystallized directly from slightly evolved liquid, or they are produced by fractional crystallization with a large amount of trapped liquid

    切片剥離法による細胞壁層のフィビリル傾角計測法

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    細胞壁のフィブリル傾角は木材の物性に非常に影響するので, これまで種々の方法で測定されてきた。偏光顕微鏡法は手軽で精度の高い測定を可能とするが, この測定に必須である細胞壁のsingle wall化が困難なために, 未だ充分には活用されてはいない。そこで極めて簡単な操作で, 各種の木材細胞壁のsingle wallを得る方法を考案した。その概略はまず細胞直径程度の厚さの縦断切片を乾燥し, その両面に透明なエポキシ樹脂液を塗布して2枚のスライドガラスに挟み, 圧締しながら硬化させる。この時, 孔をあけたポリエチレンフィルムで切片を囲んでおく。この2枚のスライドを剥すと切片に含まれていたdouble wallは両側に引き剥されてsingle wallとなる。この時, S_1とS_2との境界で剥離する場合もある。剥離面に再び樹脂液を塗布して同様の操作を繰り返していくと, 細胞壁はさらに薄片化しS_1, S_2, S_3などの個々の細胞断層を単離できる。そして剥離面をカナダバルサムで封入し偏光顕微鏡観察に供する。その結果, 細胞壁各部での消光位から壁の平均フィブリル傾角が容易に測定される。これに加えて, 剥離の際にフィブリルに平行な条線が多数発生した。これらは背景となる細胞壁を対角位にすると明瞭に観察できるので、個々の壁層のフィブリル傾角を非常に能率的に計測することが可能となった。For measurement of fibril angle using the polarizing microscope, a very effective method was devised. Longitudinal wood sections are sandwiched with epoxy resin between two glass slides, and splitted with the glass slides after curring. By this very simple preparation, a series of single walls and even respective wall layers could be obtained. These splitted-sections were shown to be really suitable in measurement of both average fibril angle and individual one of various wall layers. The former was estimated by the extinction position under crossed polars, while the latter became possible at the diagonal position to be determined from many striations along microfibrils occurred during the sample preparation

    Performance analysis and optimization of a distributed processing framework for data mining accelerated with graphics processing units

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    In this age, a huge amount of data is generated every day by human interactions with services. Discovering the patterns of these data are very important to take business decisions. Due to the size of this data, it requires very high intensive computation power. Thus, many frameworks have been developed using Central Processing Units (CPU) implementations to perform this computation. For instance, a distributed and parallel programming model such as Google's MapReduce. On the other hand, since the last half decade, researchers have started using Graphics Processing Units (GPU) performance to process these huge data. Unlike CPU, GPU can execute many tasks in parallel. To measure the performance of GPU, EURA NOVA implemented two data mining algorithms (K-Means and Naive Bayes) in the framework to enable task execution in a distributed manner by considering availability of GPU power in each node. Even though the framework was successfully implemented, when compared to another CPU parallel framework, its performance was very poor. It shows that the framework does not use the performance of GPU effectively. Moreover, it contradicts with the fact that GPU can execute many tasks in parallel and thus, faster than CPU implementation. As a result, this research topic started with the objective to answer how to improve this performance. Specifically, to improve the performance of the K-Means implementation. We also included a new data mining implementation called Expectation Maximization to the framework, taking advantage of each GPU node and the distribution nodes. Furthermore, we address some good practices when implementing data mining in GPU from a sequential design. Working with general purpose GPU is still in development stage. A well known library is Thrust. We used it to achieve the above objectives. Finally, we evaluated our solutions by comparing with other existed CPU frameworks. The results show that we improved the K-Means performance more than 130x, and plugged the expectation maximization implementation into EURA NOVA's framework

    A Case of Inferior Vena Cava Obstruction Associated with Budd - Chiari Syndrome

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    The inferior vena cava obstruction is a relatively rare disease. The majority of the obstruction is located at the lower two third of the inferior vena cava, while the upper obstruction is frequently associated with hepatic vein obstruction (1,2). Approximately 200 cases of Budd-Chiari syndrome (3,4) have been reported in the literature (5). The association of inferior vena cava obstruction with Budd-Chiari syndrome has been occasionally reported, but an ante-mortem diagnosis of this condition is not necessarily easy. With the progress in the technic of angiography, venous catheterization or liver biopsy, successful ante-mortem diagnosis and surgical treatments increased (6-10), but the ideal treatment of this complicated disease has not yet been established. Recently, we experienced a case of this rare condition and performed a shunt operation using an artificial vessel graft

    Radically Different Thioredoxin Domain Arrangement of ERp46, an Efficient Disulfide Bond Introducer of the Mammalian PDI Family

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    SummaryThe mammalian endoplasmic reticulum (ER) contains a diverse oxidative protein folding network in which ERp46, a member of the protein disulfide isomerase (PDI) family, serves as an efficient disulfide bond introducer together with Peroxiredoxin-4 (Prx4). We revealed a radically different molecular architecture of ERp46, in which the N-terminal two thioredoxin (Trx) domains with positively charged patches near their peptide-binding site and the C-terminal Trx are linked by unusually long loops and arranged extendedly, forming an opened V-shape. Whereas PDI catalyzes native disulfide bond formation by the cooperative action of two mutually facing redox-active sites on folding intermediates bound to the central cleft, ERp46 Trx domains are separated, act independently, and engage in rapid but promiscuous disulfide bond formation during early oxidative protein folding. Thus, multiple PDI family members likely contribute to different stages of oxidative folding and work cooperatively to ensure the efficient production of multi-disulfide proteins in the ER

    Surgical repair for aortic dissection accompanying a right-sided aortic arch

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    Aortic anomaly in which a right-sided aortic arch associated with Kommerell's diverticulum and aberrant left subclavian artery is rare. The present report describes a patient with type-B aortic dissection accompanying aortic anomalies consisting of right-sided aortic arch and the left common carotid and left subclavian artery arising from Kommerell's diverticulum. As dissecting aortic aneurysm diameter increased rapidly, Single-stage surgical repair of extensive thoracic aorta was performed through median sternotomy and right posterolateral fifth intercostal thoracotomy, yielding favorable results. Our surgical procedures are discussed
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