Crystal structure of citric acid-acetonitrile (1/1), C₈H₁₁NO₇

Liu, Yang,Zheng, Xiao-Yuan,Qin, Liu-Lei,Zhu, Chun-Li,Liu, Zunqi De Gruyter 2019 Zeitschrift für Kristallographie. New crystal Vol.234 No.2

<P><B>Abstract</B></P><P>C<SUB>8</SUB>H<SUB>11</SUB>NO<SUB>7</SUB>, triclinic,<I>P</I>1̄ (no. 2),<I>a</I>= 5.5944(13) Å,<I>b</I>= 10.402(3) Å,<I>c</I>= 10.666(3) Å,<I>α</I>= 110.297(2)<SUP><I>o</I></SUP>,<I>β</I>= 101.342(3)<SUP><I>o</I></SUP>,<I>γ</I>= 104.701(2)<SUP><I>o</I></SUP>,<I>V</I>= 534.6(2) Å<SUP>3</SUP>,<I>Z</I>= 2,<I>R</I><SUB>gt</SUB>(<I>F</I>) = 0.0318,<I>wR</I><SUB>ref</SUB>(<I>F</I><SUP>2</SUP>) = 0.0833,<I>T</I>= 293(2) K.</P>

Suppression of Ku80 Correlates with Radiosensitivity and Telomere Shortening in the U2OS Telomerase-negative Osteosarcoma Cell Line

Hu, Liu,Wu, Qin-Qin,Wang, Wen-Bo,Jiang, Huan-Gang,Yang, Lei,Liu, Yu,Yu, Hai-Jun,Xie, Cong-Hua,Zhou, Yun-Feng,Zhou, Fu-Xiang Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.2

Ku70/80 heterodimer is a central element in the nonhomologous end joining (NHEJ) DNA repair pathway, Ku80 playing a key role in regulating the multiple functions of Ku proteins. It has been found that the Ku80 protein located at telomeres is a major contributor to radiosensitivity in some telomerase positive human cancer cells. However, in ALT human osteosarcoma cells, the precise function in radiosensitivity and telomere maintenance is still unknown. The aim of this study was to investigate the effects of Ku80 depletion in the U2OS ALT cell line cell line. Suppression of Ku80 expression was performed using a vector-based shRNA and stable Ku80 knockdown in cells was verified by Western blotting. U2OS cells treated with shRNA-Ku80 showed lower radiobiological parameters (D0, Dq and SF2) in clonogenic assays. Furthermore, shRNA-Ku80 vector transfected cells displayed shortening of the telomere length and showed less expression of TRF2 protein. These results demonstrated that down-regulation of Ku80 can sensitize ALT cells U2OS to radiation, and this radiosensitization is related to telomere length shortening.

Improved photochemical properties of Aurivillius Bi₅Ti₃FeO₁₅ with partial substitution of Ti⁴⁺ with Fe³⁺

Liu, Xuanxuan,Xu, Lei,Huang, Yanlin,Qin, Chuanxiang,Qin, Lin,Seo, Hyo Jin Elsevier 2017 CERAMICS INTERNATIONAL Vol.43 No.15

<P><B>Abstract</B></P> <P>This work improved the optical absorption and photocatalytic ability of four-layered Aurivillius Bi<SUB>5</SUB>Ti<SUB>3</SUB>FeO<SUB>15</SUB> through microstructural modification via partial substitution of Ti<SUP>4+</SUP> with Fe<SUP>3+</SUP>. Bi<SUB>5</SUB>Ti<SUB>3−x</SUB>Fe<SUB>1+x</SUB>O<SUB>15</SUB> (x = 0–0.6) photocatalysts were prepared through sol-gel citrate-complexation synthesis. The sample crystallized into plate-like nanoparticles with [001] facets. Phase formation and crystal structure were confirmed via X-ray powder diffraction (XRD) Rietveld refinements. Bi<SUB>5</SUB>Ti<SUB>3−x</SUB>Fe<SUB>1+x</SUB>O<SUB>15</SUB> (x = 0–0.6) maintained its structural characteristic, i.e., a perovskite unit of (Bi<SUB>3</SUB>Ti<SUB>3−x</SUB>Fe<SUB>1+x</SUB>O<SUB>13</SUB>)<SUP>2–</SUP> sandwiched by two (Bi<SUB>2</SUB>O<SUB>2</SUB>)<SUP>2+</SUP> layers along <I>c</I> axis. The samples were investigated via scanning electron microscope (SEM), transmission electron microscope (TEM), energy-dispersive X-ray spectroscopy (EDX), and specific surface area analyses. The band gap showed characteristic transitions from the valence band (VB) of (O2p+Fe<I>t</I> <SUB>2g</SUB>+Bi6s) to the conduction band (CB) of (Ti-3d+Fe-<I>e</I> <SUB>g</SUB>). With increasing substitution of Ti<SUP>4+</SUP> with Fe<SUP>3+</SUP>, the sample greatly red shifted its absorption edges. The d–d transitions in FeO<SUB>6</SUB> greatly contribute to the narrow band-gap. Aurivillius is a potential photocatalyst and demonstrated photodegradation of Rhodamine B (RhB) under visible light irradiation (λ > 420nm). Such photocatalytic activities were attributed to the special structural layer and the catalytic mediators of multivalent Ti<SUP>4+/3+</SUP> and Fe<SUP>3+/2+</SUP> ions in the perovskite slabs as confirmed by XPS measurements. Results suggested that substitution of Ti<SUP>4+</SUP> with Fe<SUP>3+</SUP> in an Aurivillius phase was an efficient method to modify the bandwidth and structure of Aurivillius phase. This phenomenon can be used as a strategy to improve the photochemical properties of Ti/Fe-containing Aurivillius phases.</P>

Iterative coupling of precise integration FEM and TD-BEM for elastodynamic analysis

Lei, Weidong,Liu, Chun,Qin, Xiaofei,Chen, Rui Techno-Press 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.67 No.4

The iterative decomposition coupling formulation of the precise integration finite element method (FEM) and the time domain boundary element method (TD-BEM) is presented for elstodynamic problems. In the formulation, the FEM node and the BEM node are not required to be coincident on the common interface between FEM and BEM sub-domains, therefore, the FEM and BEM are independently discretized. The force and displacement converting matrices are used to transfer data between FEM and BEM nodes on the common interface between the FEM and BEM sub-domains, to renew the nodal variables in the process of the iterations for the un-coincident FEM node and BEM node. The iterative coupling formulation for elastodynamics in current paper is of high modeling accuracy, due to the semi-analytical solution incorporated in the precise integration finite element method. The decomposition coupling formulation for elastodynamics is verified by examples of a cantilever bar under a Heaviside-type force and a harmonic load.

S-Adenosylmethionine enhances the inhibitory effect of gemcitabine against pancreatic cancer cells via suppression of the EGFR/AKT pathways

Liu Yan,Liu Linxun,Zhang Yang,Qin Lei 대한독성 유전단백체 학회 2022 Molecular & cellular toxicology Vol.18 No.4

Background Natural chemical SAM (S-adenosylmethionine) is present in all living cells and plays an important role in biological transmethylation. Recent studies have shown that SAM possesses many pharmacological activities including anti-cancer effects. However, the complex formation of SAM with gemcitabine on pancreatic carcinoma cells, as well as the specific mechanism, remains unknown. Objectives Pancreatic cancer cells (PANC-1 and BxPC-3) were treated with SAM and/or gemcitabine and subjected to MTT, combination index, cell apoptosis, cell migration, western blot, and xenograft tumorigenicity assays in this research. Results The findings revealed that SAM might synergistically improve gemcitabine’s capacity to prevent the development and proliferation of pancreatic cancer cells. By decreasing the EGFR/AKT pathways, SAM in combination with gemcitabine might promote cell death and impede cell migration. Furthermore, pretreatment with IGF-1 (a particular AKT activator) drastically reduced SAM’s pro-apoptotic activity in pancreatic cancer cells, demonstrating the importance of AKT in this mechanism. Furthermore, following treatment with SAM with gemcitabine, tumor volume and weight were considerably decreased in the PANC-1 xenograft mouse model, and immunohistochemical analysis confi rmed the down-regulation of p-EGFR and p-AKT in tumor tissues. Conclusion By suppressing the EGFR/AKT pathways, SAM could synergistically boost the inhibitory impact of gemcitabine on pancreatic cancer cells and might be a promising therapeutic drug for the management of pancreatic cancer.

A silver niobate photocatalyst AgNb₇O₁₈ with perovskite-like structure

Liu, XuanXuan,Qin, Chuanxiang,Cao, Lei,Feng, Yongyi,Huang, Yanlin,Qin, Lin,Seo, Hyo Jin Elsevier 2017 Journal of Alloys and Compounds Vol.724 No.-

<P><B>Abstract</B></P> <P>Silver-containing niobate AgNb<SUB>7</SUB>O<SUB>18</SUB> nanoparticles were prepared via sol-gel polymerized complex synthesis. The sample was given a good XRD Rietveld refinement in a typical perovskite-like structure. The detailed surface properties of AgNb<SUB>7</SUB>O<SUB>18</SUB> nanoparticles were tested by SEM, EDS, TEM, nitrogen adsorption-desorption isotherms and XPS measurements. AgNb<SUB>7</SUB>O<SUB>18</SUB> is characterized via a direct transition and the band energy is 2.76 eV. The hybridization between O 2p and Ag 3d states in valence band contributes to the narrowed band gap. The first principles electronic structure elucidation supports the narrow band gap of AgNb<SUB>7</SUB>O<SUB>18</SUB>. The sample shows an efficient degradation of methylene blue dye (MB) solutions. The trapping tests were performed to elucidate the real active species in the photocatalytic reactions. The results indicate that the superoxide radical is the main active species in the photocatalytic system, and the photocatalyst also shows a good stability and durability.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A new semiconductor nanoparticle AgNb<SUB>7</SUB>O<SUB>18</SUB> was prepared. </LI> <LI> The silver niobate has a typical perovskite-like structure. </LI> <LI> AgNb<SUB>7</SUB>O<SUB>18</SUB> shows an efficient absorption with a narrow gap 2.76 eV. </LI> <LI> AgNb<SUB>7</SUB>O<SUB>18</SUB> has an efficient photocatalytic activity on MB photo-degradation. </LI> <LI> The photocatalysis mechanism and stabilities were discussed. </LI> </UL> </P>

Analysis on an improved resistance tuning type multi-frequency piezoelectric spherical transducer

Lei Qin,Jianjun Wang,Donghuan Liu,Lihua Tang,Gangbing Song 국제구조공학회 2019 Smart Structures and Systems, An International Jou Vol.24 No.4

The existing piezoelectric spherical transducers with fixed prescribed dynamic characteristics limit their application in scenarios with multi-frequency or frequency variation requirement. To address this issue, this work proposes an improved design of piezoelectric spherical transducers using the resistance tuning method. Two piezoceramic shells are the functional elements with one for actuation and the other for tuning through the variation of load resistance. The theoretical model of the proposed design is given based on our previous work. The effects of the resistance, the middle surface radius and the thickness of the epoxy adhesive layer on the dynamic characteristics of the transducer are explored by numerical analysis. The numerical results show that the multi-frequency characteristics of the transducer can be obtained by tuning the resistance, and its electromechanical coupling coefficient can be optimized by a matching resistance. The proposed design and derived theoretical solution are validated by comparing with the literature given special examples as well as an experimental study. The present study demonstrates the feasibility of using the proposed design to realize the multi-frequency characteristics, which is helpful to improve the performance of piezoelectric spherical transducers used in underwater acoustic detection, hydrophones, and the spherical smart aggregate (SSA) used in civil structural health monitoring, enhancing their operation at the multiple working frequencies to meet different application requirements.

Identification and characterization of atypical porcine pestivirus genomes in newborn piglets with congenital tremor in China

Han-Qin Shen,Xiangcong Liu,Pengfei Zhang,Lei Wang,Yan-ling Liu,Le-yi Zhang,Peng-shuai Liang,Chang-xu Song 대한수의학회 2018 Journal of Veterinary Science Vol.19 No.3

Recently, a novel atypical porcine pestivirus (APPV) in pig was reported. In this study, two APPV strains, APPV-China/GZ01/2016 (GZ01) and APPV-China/GD-SD/2016 (GD-SD), were identified in two newborn piglet herds with congenital tremor from China. The open reading frame of the two strains shared an 83.5% nucleotide identity. Phylogenetically, the APPV strains were placed into two groups: GZ01 belonged to group I and GD-SD belonged to group II. A high viral load was detected in the cerebellum (quantification cycles < 26). Further studies should be carried out to thoroughly elucidate the development of congenital tremors caused by APPV.

Iterative coupling of precise integration FEM and TD-BEM for elastodynamic analysis

Weidong Lei,Chun Liu,Xiaofei Qin,Rui Chen 국제구조공학회 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.67 No.4

The iterative decomposition coupling formulation of the precise integration finite element method (FEM) and the time domain boundary element method (TD-BEM) is presented for elstodynamic problems. In the formulation, the FEM node and the BEM node are not required to be coincident on the common interface between FEM and BEM sub-domains, therefore, the FEM and BEM are independently discretized. The force and displacement converting matrices are used to transfer data between FEM and BEMnodes on the common interface between the FEM and BEM sub-domains, to renew the nodal variables in the process of the iterations for the un-coincident FEM node and BEM node. The iterative coupling formulation for elastodynamics in current paper is of high modeling accuracy, due to the semi-analytical solution incorporated in the precise integration finite element method. The decomposition coupling formulation for elastodynamics is verified by examples of a cantilever bar under a Heaviside-type force and a harmonic load.

The nonlinear galloping of iced transmission conductor under uniform and turbulence wind

Zhonghua Liu,Chenhui Ding,Jian Qin,Ying Lei 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.75 No.4

The analytical approach for stability and response of iced conductor under uniform wind or turbulent wind is presented in this study. A nonlinear dynamic model is established to describe the motion of iced conductor galloping. In the case of uniform wind, the stability condition is derived by analyzing the eigenvalue associated with linearized matrix; The first order and second order approximation of galloping amplitude are obtained using multi-scale method. However, real wind has random characteristics essentially. To accurately evaluate the performance of the galloping iced conductor, turbulence wind should be described by random processes. In the case of turbulence wind, the Lyapunov exponent is conducted to judge the stability condition; The probability density of displacement is obtained by using the path integral method to predict galloping amplitude. An example is proposed to verify the effectiveness of the previous methods. It is shown that the fluctuating component of wind has little influence on the stability of iced conductor, but it can increase galloping amplitude. The analytical results on stability and response are also verified by numerical time stepping method.