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Transcriptional elongation factor Paf1 core complex adopts a spirally wrapped solenoidal topology
Deng, Pujuan,Zhou, Yuqiao,Jiang, Junyi,Li, Haojie,Tian, Wei,Cao, Yinghua,Qin, Yan,Kim, Jaehoon,Roeder, Robert G.,Patel, Dinshaw J.,Wang, Zhanxin National Academy of Sciences 2018 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.115 No.40
<▼1><P><B>Significance</B></P><P>The polymerase-associated factor 1 (PAF1) complex is a general transcription elongation factor of RNA polymerase II, which not only regulates various stages of the transcription cycle but also broadly influences gene expression through modulating chromatin structure and/or recruiting other transcription-related factors. This study presents a high-resolution crystal structure of the core region of the Paf1-Ctr9-Cdc73 ternary complex, which not only greatly facilitates our understanding of the overall architecture of the Paf1 complex but also provides a structure-based platform for understanding the molecular mechanism underlying the role of the Paf1 complex in regulating gene expression and sheds light toward deciphering the impact of its mutational spectrum on human diseases.</P></▼1><▼2><P>The polymerase-associated factor 1 (Paf1) complex is a general transcription elongation factor of RNA polymerase II, which is composed of five core subunits, Paf1, Ctr9, Cdc73, Leo1, and Rtf1, and functions as a diverse platform that broadly affects gene expression genome-wide. In this study, we solved the 2.9-Å crystal structure of the core region composed of the Ctr9-Paf1-Cdc73 ternary complex from a thermophilic fungi, which provides a structural perspective of the molecular details of the organization and interactions involving the Paf1 subunits in the core complex. We find that Ctr9 is composed of 21 tetratricopeptide repeat (TPR) motifs that wrap three circular turns in a right-handed superhelical manner around the N-terminal region of an elongated single-polypeptide–chain scaffold of Paf1. The Cdc73 fragment is positioned within the surface groove of Ctr9, where it contacts mainly with Ctr9 and minimally with Paf1. We also identified that the Paf1 complex preferentially binds single-strand–containing DNAs. Our work provides structural insights into the overall architecture of the Paf1 complex and paves the road forward for understanding the molecular mechanisms of the Paf1 complex in transcriptional regulation.</P></▼2>
POSITIVE SOLUTIONS OF THE SECOND-ORDER SYSTEM OF DIFFERENTIAL EQUATIONS IN BANACH SPACES
Cao, Jianxin,Chen, Haibo,Deng, Jin The Korean Society for Computational and Applied M 2010 Journal of applied mathematics & informatics Vol.28 No.5
In this paper, a second-order system of multi-point boundary value problems in Banach spaces is investigated. Based on a specially constructed cone and the fixed point theorem of strict-set-contraction operators, the criterion of the existence and multiplicity of positive solutions are established. And two examples demonstrating the theoretic results are given.
Experimental investigation of masonry walls supported by steel plate-masonry composite beams
Deng-Hu Jing,Jian-Fei Chen,Giuseppina Amato,Ting Wu,Shuang-Yin Cao 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.28 No.6
Masonry walls are sometimes removed in buildings to either make new passages or increase the usable space. This may change the loading paths in the structure, and require new beams to transfer the loads which are carried by the masonry walls that are to be removed. One possible method of creating such new beams is to attach steel plates onto part of the existing walls to form a steel plate-masonry composite (SPMC) beam, leading to a new structure with part of the masonry wall supported by a new SPMC beam. This paper presents an experimental investigation into the interaction between the SPMC beam and the masonry wall above. Five SPMC beams supporting a masonry wall were tested to study the influence of parameters including the height-to-span ratio of the masonry wall, height of the beam and thickness of the steel plates. The test results, including failure mode, load-carrying capacity, load-deflection curves and strain distribution, are presented and discussed. It is found that for developing better arching effect in the masonry wall the ratio of the in-plane flexural stiffness of the masonry wall to the flexural stiffness of the SPMC beam must be between 2.8 and 7.1.
Flexural behaviour of steel plate-masonry composite beams
Deng-Hu Jing,Shuang-Yin Cao,Lei Shi 국제구조공학회 2012 Steel and Composite Structures, An International J Vol.13 No.2
Steel plate-masonry composite structure is a newly-developed type of structural technique applicable to existing masonry buildings by which the load-bearing walls can be removed for large spaces. This kind of structure has been used in practice for its several advantages, but experimental investigation on its elements is nearly unavailable in existing literature. This paper presents an experimental study on the flexural behaviour of four steel plate-masonry composite beams loaded by four-point bending. Test results indicate that failure of the tested beams always starts from the local buckling of steel plate, and that the tested beams can satisfy the requirement of service limit state. In addition, the assumption of plane section is still remained for steel plate prior to local buckling or steel yielding. By comparative analyses, it was also verified that the working performance of the beam is influenced by the cross-section of steel plate, which can be efficiently enhanced by epoxy adhesive rather than cement mortar or nothing at all. Besides, it was also found that the contribution of the encased masonry to the flexural capacity of the composite beam cannot be ignored when the beam is injected with epoxy adhesive.
Cao, Chao,Sun, Shi-Fang,Lv, Dan,Chen, Zhong-Bo,Ding, Qun-Li,Deng, Zai-Chun Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.4
Published data have shown that the levels of vascular endothelial growth factor (VEGF) and soluble VEGF receptor-1 (sVEGFR-1) in plasma and pleural effusion might be usefulness for lung cancer diagnosis. Here, we performed a prospective study to investigate the utility of VEGF and sVEGFR-1 in bronchoalveolar lavage fluid (BALF) for differential diagnosis of primary lung cancer. A total of 56 patients with solitary pulmonary massed by chest radiograph or CT screening were enrolled in this study. BALF and plasma samples were obtained from all patients and analyzed for VEGF and sVEGFR-1 using a commercially available sandwich ELISA kit. The results showed that the levels of VEGF in BALF were significantly higher in patients with a malignant pulmonary mass compared with patients with a benign mass (P < 0.001). However, no significant difference of sVEGFR-1 in BALF was found between malignant and non-malignant groups (P = 0.43). With a cut-off value of 214 pg/ml, VEGF showed a sensitivity and specificity of 81.8% and 84.2%, respectively, in predicting the malignant nature of a solitary pulmonary mass. Our study suggests that VEGF is significantly increased in BALF among patients with lung cancer than in benign diseases. Measurement of VEGF in BALF might be helpful for differential diagnosis of primary lung cancer.
Yu Cao,Ruyi Deng,Jilin Hu,Jinxiu He,Dapeng Lei,Zhanjun Chen,Yangxi Peng 한양대학교 청정에너지연구소 2023 Journal of Ceramic Processing Research Vol.24 No.2
SiC-B4C composite powders were synthesized by the carbothermal reduction method under an argon atmosphere usingdifferent kinds of carbon sources (carbon black and starch) and silica sol and boric acid as the precursor raw materials. Basedon thermodynamic analysis and calculation, the effects of different carbon sources and reaction temperatures on the mass lossrate, phase composition, and microstructure of SiC-B4C ultrafine composite powders were comparatively studied. Resultsshowed that the optimum conditions for synthesizing SiC-B4C composite powders with carbon black as the carbon source were1550 ºC for 2 h, whereas the optimum conditions for synthesizing SiC-B4C composite powders with starch as the carbon sourcewere 1450 ºC-1550 ºC for 2 h. The powder samples synthesized with carbon black as the carbon source at 1550 ºC were mainlycomposed of flaky, columnar-like, spherical, and irregular polyhedral particles (about 100-200 nm in diameter). Mutualcohesion or agglomeration between particles was minimal. In the powder samples synthesized at 1550 ºC with an excess of 10wt% starch, in addition to a certain amount of flaky, spherical, and other irregular structure particles, a certain amount ofuniform, slender whiskers (about 50-100 nm in diameter) and a certain phenomenon of lap and winding between the whiskerswere noted. The powder samples synthesized at 1550 ºC with an excess of 20 wt% starch had no whisker-like substance.
Miao Cao,Hui‑Qin Chen,Kun‐Kun Deng,Xing‑Wang Duan,Shuang Liu,Xin Che,Fei Li 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.5
Ti/Al multilayered composites (LMCs) with 3-layers, 5-layers and 7-layers were prepared by hot‐pressing and hot‐rolling. Theeffects of the interface on the mechanical properties and stamping formability of LMCs were revealed. The results indicatethat the TiAl3phases at the interface thicken gradually with the increase of layers. As the layers of LMCs increases, boththe grain size and the basal texture strength of Ti decrease, and Ti possesses a higher Schmid factors (SF) and more uniformSF distribution, which promotes the overall coordinated deformation of LMCs. The elongation (EL) of LMCs graduallyincreases at the expense of the strength with the increase of layers. The stress–strain transfer across the interface, the releaseof residual stress through interfacial microcracks, and the improvement of the interfacial metallurgical bonding strengthare all conducive to the coordinated deformation between Ti and Al layers, thus the strength of LMCs decreases and theEL enhances. Both the yield strength ratio (σs/σb) and plastic strain ratio (r) decrease, while the strain-hardening exponent(n) increases with the increase of layers of LMCs, which are beneficial to improve the stamping formability of LMCs. Thenumber of interface increases with the increase of layers, which hinders crack propagation. Moreover, the microcracks areeasily induced by the brittle TiAl3phase at the interface, and the main cracks deflect obviously and release part energy inthe form of secondary microcracks, thus delaying the failure of LMCs and improving their stamping formability.
POSITIVE SOLUTIONS OF THE SECOND-ORDER SYSTEM OF DIFFERENTIAL EQUATIONS IN BANACH SPACES
Jianxin Cao,Haibo Chen,Jin Deng 한국전산응용수학회 2010 Journal of applied mathematics & informatics Vol.28 No.5
In this paper, a second-order system of multi-point boundary value problems in Banach spaces is investigated. Based on a specially constructed cone and the fixed point theorem of strict-set-contraction operators, the criterion of the existence and multiplicity of positive solutions are established. And two examples demonstrating the theoretic results are given.