967 research outputs found

    RNA interference technology's research progress in the treatment of retinal disease

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    RNA interference exists widely in animals, which can induce specific genetic sequence to silence by double-stranded RNA molecules at the mRNA level. As a kind of new methods of blocking gene expression, RNA interference technology has become increasingly mature and perfect, it has opened up a new approach of gene therapy. RNA interference can effectively prevent the formation of new vessels in retina, restrain the occurrence and development of the proliferative vitreous retinopathy, and induce apoptosis of retinoblastoma cells. The research progress of the RNA interference in the above retinopathy was summarized in this review

    Converting Hybrid Wire-frames to B-rep Models

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    International audienceSolid reconstruction from engineering drawings is one of the efficient technologies to product solid models. The B-rep oriented approach provides a practical way for reconstructing a wide range of objects. However, its major limitation is the computational complexity involved in the search for all valid faces from the intermediate wire-frame, especially for objects with complicated face topologies. In previous work, we presented a hint-based algorithm to recognize quadric surfaces from orthographic views and generate a hybrid wire-frame as the intermediate model of our B-rep oriented method. As a key stage in the process of solid reconstructing, we propose an algorithm to convert the hybrid wire-frame to the final B-rep model by extracting all the rest faces of planes based on graph theory. The entities lying on the same planar surface are first collected in a plane graph. After all the cycles are traced in a simplified edge-adjacency matrix of the graph, the face loops of the plane are formed by testing loop containment and assigning loop directions. Finally, the B-rep model is constructed by sewing all the plane faces based on the Mšobius rule. The method can efficiently construct 2- manifold objects with a variety of face topologies, which is illustrated by results of implementatio

    Zc(3900)Z_c(3900) as a DDˉ∗D\bar{D}^* molecule from the pole counting rule

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    A comprehensive study on the nature of the Zc(3900)Z_c(3900) resonant structure is carried out in this work. By constructing the pertinent effective Lagrangians and considering the important final-state-interaction effects, we first give a unified description to all the relevant experimental data available, including the J/ψπJ/\psi\pi and ππ\pi\pi invariant mass distributions from the e+e−→J/ψππe^+e^-\to J/\psi\pi\pi process, the hcπh_c\pi distribution from e+e−→hcππe^+e^-\to h_c\pi\pi and also the DDˉ∗D\bar D^{*} spectrum in the e+e−→DDˉ∗πe^+e^-\to D\bar D^{*}\pi process. After fitting the unknown parameters to the previous data, we search the pole in the complex energy plane and find only one pole in the nearby energy region in different Riemann sheets. Therefore we conclude that Zc(3900)Z_c(3900) is of DDˉ∗D\bar D^* molecular nature, according to the pole counting rule method~[Nucl.~Phys.~A543, 632 (1992); Phys.~Rev.~D 35,~1633 (1987)]. We emphasize that the conclusion based upon the pole counting method is not trivial, since both the DDˉ∗D\bar D^{*} contact interactions and the explicit ZcZ_c exchanges are introduced in our analyses and they lead to the same conclusion.Comment: 21 pages, 9 figures. To match the published version in PRD. Additional discussion on the spectral density function is include

    (Z)-3-(9-Anthr­yl)-1-(4-bromo­phen­yl)-2-(4-nitro-1H-imidazol-1-yl)prop-2-en-1-one

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    In the title mol­ecule, C26H16BrN3O3, the anthracene and benzene mean planes make dihedral angles of 63.79 (2) and 14.67 (2)°, respectively, with the plane of the imidazole ring. In the crystal structure, weak inter­molecular C—H⋯O hydrogen bonds link mol­ecules to form centrosymmetric dimers. Weak π–π stacking inter­actions, with centroid–centroid distances of 3.779 (2) and 3.826 (2) Å, supply additional stabilization. The crystal packing also exhibits short inter­molecular contacts between the nitro groups and Br atoms [Br⋯O = 3.114 (2) Å]

    Fuyuanichthys wangi gen. et sp. nov. from the Middle Triassic (Ladinian) of China highlights the early diversification of ginglymodian fishes

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    A series of well-preserved fossil assemblages from the Middle Triassic marine rock succession in Southwest China provide unique evidences for studying the early evolution of holostean fishes, including Halecomorphi (e.g., bownfin) and Ginglymodi (e.g., gars). Ginglymodi have the earliest record in the early Middle Triassic (Anisian, ∌244 Ma) of China, represented by Kyphosichthys and Sangiorgioichthys sui from Yunnan and S. yangjuanensis from Guizhou. Here, we report the discovery of a new ginglymodian, Fuyuanichthys wangi gen. et sp. nov., based on 22 well-preserved specimens from the lower part of the Zhuganpo member of the Falang Formation in eastern Yunnan and western Guizhou, which documents the first discovery of convincing ginglymodians from the late Middle Triassic (Ladinian, ∌240 Ma) Xingyi biota in China. Fuyuanichthys possesses a unique combination of features that easily distinguishes it from other ginglymodians, such as presence of a median gular and short and edentulous maxillae, and absence of a supramaxilla and supraorbitals. As one of the smallest known ginglymodians with a maximum standard length of ∌75 mm, the new finding further supports that the Middle Triassic Ginglymodi have a relatively small range of body sizes compared with the Halecomorphi from the same ecosystems in China. Results of a phylogenetic analysis recover Fuyuanichthys as a sister taxon to Kyphosichthys at the ginglymodian stem, and provide new insights into the early evolution of this clade

    The unidirectional valve patch provides no benefits to early and long-term survival in patients with ventricular septal defect and severe pulmonary artery hypertension

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    ObjectiveOur aim was to test whether a unidirectional valve patch would provide benefit to early and long-term survival for patients with ventricular septal defect and severe pulmonary artery hypertension.MethodsEight hundred seventy-six cases of ventricular septal defect with severe pulmonary artery hypertension were closed with or without a unidirectional valve patch and were classified as the unidirectional valve patch (UVP) group (n = 195) and nonvalve patch (NVP) group (n = 681), respectively. Propensity scores of inclusion into the UVP group were used to match 138 pairs between the 2 groups. Kaplan–Meier survival curves were constructed to compare early and long-term survival.ResultsFor the 138 propensity-matched pairs, there were 7 and 9 early deaths (in-hospital deaths) in the UVP and NVP groups, respectively. The difference in early mortality between the 2 groups did not reach statistical significance (χ2 = 0.265, P = .6064). With a mean of 9.2 ± 4.92 years' and 2511 patient-years' follow-up, there were 6 late deaths in the UVP group and 7 late deaths in the NVP group. The difference in actuarial survival at 5, 10, 15, and 18 years between the 2 groups was not significant (log-rank test, χ2 = 0.565, P = .331). The difference in the late mortality between the groups with or without a patent patch at the time of discharge did not reach statistical significance (χ2 = 1.140, P = .2856). There was no difference between the 2 groups in the 6-minute walk distance assessed at the last follow-up (525.9 ± 88.0 meters for the UVP group and 536.5 ± 95.8 meters for the NVP group, F = 1.550, P = .214).ConclusionA unidirectional valve patch provides no benefits to early and long-term survival when it is used to deal with ventricular septal defect and severe pulmonary artery hypertension
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