254 research outputs found
5,5-Bis(4-methoxyphenyl)-2,8-bis[3-(trifluoromethyl)phenyl]-5H-cyclopenta[2,1-b:3,4-b’]dipyridine
The title compound, C39H26F6N2O2, showed two melting transitions 477.4 and 506.5 K in a differential scanning calorimetry (DSC) study. The first of these can be attributed to a melting phase transition arising from the rotation of two trifluoromethyl groups. In the crystal structure, both trifluoromethyl groups are disordered over two sites with occupancy factors of 0.660 (17) and 0.340 (17) for the major and minor orientations, respectively. The introduction of trifluoromethyl groups inhibits π-stacking between the diazafluorene (cyclopenta[2,1-b:3,4-b’]dipyridine) units. Three short F⋯O contacts between 2.80 (3) and 2.95 (1) Å are observed in the crystal structure
5,5′-Di-4-pyridyl-2,2′-(5-tert-butyl-m-phenylene)bis(1,3,4-oxadiazole)
The title compound, C24H20N6O2, is a novel 1,3,4-oxadiazole derivative which has potential as an electron-transporting material in organic electroluminescent (EL) devices. In the crystal, the molecular framework is almost planar with an r.m.s. deviation of 0.091 (4) Å and it exists in an E form. Intramolecular C—H⋯O and C—H⋯N hydrogen bonds are observed between the benzene and 1,3,4-oxadiazole rings. The tert-butyl group is disordered over two sites, with occupancy factors of 0.78 (1) and 0.22 (1) for the major and minor orientations, respectively. In the crystal structure, molecules aggregate via C—H⋯N interactions, forming molecular tapes along the b axis, which aggregate to form a molecular sheet via C—H⋯N interactions
(3Z,3′Z)-3,3′-(Ethane-1,2-diylidene)bis[isobenzofuran-1(3H)-one]
The title compound, C18H10O4, has been isolated as an impurity in commercially available 6,11-dihydroxy-5,12-naphthacenedione. The title compound exhibits yellow fluorescence in the solid state. The molecule has crystallographic inversion symmetry and is planar, with an r.m.s. deviation of 0.031 (1) Å. The crystal structure is stabilized by C—H⋯O hydrogen bonds and π–π stacking interactions between 3-methyleneisobenzofuran-1(3H)-one units [interplanar distance 3.43 (1) Å]
Efficient Installation of Gravel Drains
The gravel drain system aims to avert liquefaction in a sandy soil by quickly dissipating excess pore water pressure. We have developed a compaction-rod type machine which allows efficient construction of gravel drains. Main attributes of this machine are: (1) extremely fast installation of gravel drains, (2) low noise, (3) low level of vibration, (4) virtually no ground deformation during construction, and (5) densification of the surrounding soil. Large-scale model tests demonstrated that a cone-type compaction rod is most effective in densifying the surrounding soil when installing gravel drains with our machine
Reconstruction of ancestral brains: Exploring the evolutionary process of encephalization in amniotes
AbstractThere is huge divergence in the size and complexity of vertebrate brains. Notably, mammals and birds have bigger brains than other vertebrates, largely because these animal groups established larger dorsal telencephali. Fossil evidence suggests that this anatomical trait could have evolved independently. However, recent comparative developmental analyses demonstrate surprising commonalities in neuronal subtypes among species, although this interpretation is highly controversial. In this review, we introduce intriguing evidence regarding brain evolution collected from recent studies in paleontology and developmental biology, and we discuss possible evolutionary changes in the cortical developmental programs that led to the encephalization and structural complexity of amniote brains. New research concepts and approaches will shed light on the origin and evolutionary processes of amniote brains, particularly the mammalian cerebral cortex
Endoscopic Biliary Drainage Using Guidewire Cannulation in a Case with Severe Duodenal Stenosis Caused by Duodenal Undifferentiated Carcinoma
We present a case of duodenal carcinoma, 12 cm in size, with severe stenosis at the second portion of the duodenum. When the patient developed obstructive jaundice, it was impossible to perform endoscopic biliary drainage by standard cannulation due to the stenosis, but was succeeded by wire-guided cannulation using papillotome. Histology of the tumor showed undifferentiated carcinoma without differentiation to any specific cell type. Systemic chemotherapy was started with 5-FU, leucovorin and oxaliplatin. Biliary stent worked well until the patient succumbed three months after. Herein we demonstrate the new advantage of wire-guided cannulation in case of duodenal stenosis
脳幹の形成過程で見られる正中領域を越える細胞の移動
京都府立医科大学 大学院 神経発生生物学自然科学研究機構基礎生物学研究所 神経行動学研究部門脳幹の発生過程では、正中線を越えて反対側に移動する神経細胞がみられる。どのような仕組みで正中交差移動が制御されているのか、動眼神経核の運動ニューロンをモデルとして調べた。早期に最終分裂を行う動眼神経核ニューロンは核の前部に多くみられ交差移動しないのに対して、遅くに最終分裂する細胞は神経核内の後部に位置しており交差移動することが分かった。さらに、最終分裂の時期により、反発性軸索ガイダンス分子Slit の受容体Robo2 の発現が異なり、早くに最終分裂を行うニューロンで発現がみられた。遅くに最終分裂を迎えるニューロンはRobo2 を発現しないのでSlit に反応せず、このため正中領域を通過し反対側に移動できるものと考えられる。この結果から、正中交差移動は細胞の誕生日(最終分裂の時期)に依存した分子発現により調節されていることが示された
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