Arrays of horizontal carbon nanotubes of controlled chirality grown using designed catalysts

Zhang, Shuchen,Kang, Lixing,Wang, Xiao,Tong, Lianming,Yang, Liangwei,Wang, Zequn,Qi, Kuo,Deng, Shibin,Li, Qingwen,Bai, Xuedong,Ding, Feng,Zhang, Jin Macmillan Publishers Limited, part of Springer Nat 2017 Nature Vol.543 No.7644

<P>The semiconductor industry is increasingly of the view that Moore's law-which predicts the biennial doubling of the number of transistors per microprocessor chip-is nearing its end(1). Consequently, the pursuit of alternative semiconducting materials for nanoelectronic devices, including single-walled carbon nanotubes (SWNTs), continues(2-4). Arrays of horizontal nanotubes are particularly appealing for technological applications because they optimize current output. However, the direct growth of horizontal SWNT arrays with controlled chirality, that would enable the arrays to be adapted for a wider range of applications and ensure the uniformity of the fabricated devices, has not yet been achieved. Here we show that horizontal SWNT arrays with predicted chirality can be grown from the surfaces of solid carbide catalysts by controlling the symmetries of the active catalyst surface. We obtained horizontally aligned metallic SWNT arrays with an average density of more than 20 tubes per micrometre in which 90 per cent of the tubes had chiral indices of (12, 6), and semiconducting SWNT arrays with an average density of more than 10 tubes per micrometre in which 80 per cent of the nanotubes had chiral indices of (8, 4). The nanotubes were grown using uniform size Mo2C and WC solid catalysts. Thermodynamically, the SWNT was selectively nucleated by matching its structural symmetry and diameter with those of the catalyst. We grew nanotubes with chiral indices of (2m, m) (where m is a positive integer), the yield of which could be increased by raising the concentration of carbon to maximize the kinetic growth rate in the chemical vapour deposition process. Compared to previously reported methods, such as cloning(5,6), seeding(7,8) and specific-structure-matching growth(9-11), our strategy of controlling the thermodynamics and kinetics offers more degrees of freedom, enabling the chirality of as-grown SWNTs in an array to be tuned, and can also be used to predict the growth conditions required to achieve the desired chiralities.</P>

Promotion or Prevention? The Moderating Effect of Embedded External Reviews on Consumer Evaluations

Ziqiong Zhang,Le Wang,Shuchen Qiao,Zili Zhang Smart Tourism Research Center 2023 Journal of smart tourism Vol.3 No.3

Given the increasing information overload among users of online review websites, understanding the manner in which cognitive costs are reduced and efficient information is made reliable has become increasingly important. This study targets a unique consumer review design and explores how reviews from an external peer-to-peer site embedded in an online travel agency (OTA) website influence subsequent evaluation behaviors. The empirical results indicate that (1) embedded external reviews with a high average valence tend to strengthen the influence of the positive evaluation ratio while diminishing the effect of the review volume, and (2) embedded external reviews with a large variance strengthen the positive effect of the review volume while weakening the effect of the positive evaluation ratio on subsequent positive evaluations. The findings provide practical insights for consumers and online platforms.

LncRNA-IMAT1 Promotes Invasion of Meningiomas by Suppressing KLF4/hsa-miR22-3p/Snai1 Pathway

Tao Zhang,Yu Ge,Daijun Wang,Qin Liu,Shuchen Sun,Lingyang Hua,Jiaojiao Deng,Shihai Luan,Haixia Cheng,Qing Xie,Ye Gong,Tao Zhang 한국분자세포생물학회 2022 Molecules and cells Vol.45 No.6

Malignant meningiomas often show invasive growth that makes complete tumor resection challenging, and they are more prone to recur after radical resection. Invasive meningioma associated transcript 1 (IMAT1) is a long noncoding RNA located on Homo sapiens chromosome 17 that was identified by our team based on absolute expression differences in invasive and non-invasive meningiomas. Our studies indicated that IMAT1 was highly expressed in invasive meningiomas compared with non-invasive meningiomas. In vitro studies showed that IMAT1 promoted meningioma cell invasion through the inactivation of the Krüppel-like factor 4 (KLF4)/hsa-miR22-3p/Snai1 pathway by acting as a sponge for hsa-miR22-3p, and IMAT1 knockdown effectively restored the tumor suppressive properties of KLF4 by preserving its tumor suppressor pathway. In vivo experiments confirmed that IMAT1 silencing could significantly inhibit the growth of subcutaneous tumors and prolong the survival period of tumor-bearing mice. Our findings demonstrated that the high expression of IMAT1 is the inherent reason for the loss of the tumor suppressive properties of KLF4 during meningioma progression. Therefore, we believe that IMAT1 may be a potential biological marker and treatment target for meningiomas.

Upregulation of adiponectin by Ginsenoside Rb1 contributes to amelioration of hepatic steatosis induced by high fat diet

Yaru Li,Shuchen Zhang,Ziwei Zhu,Ruonan Zhou,Pingyuan Xu,Lingyan Zhou,Yue Kan,Jiao Li,Juan Zhao,Penghua Fang,Xizhong Yu,Wenbin Shang 고려인삼학회 2022 Journal of Ginseng Research Vol.46 No.4

Background: Ginsenoside Rb1 (GRb1) is capable of regulating lipid and glucose metabolism through itsaction on adipocytes. However, the beneficial role of GRb1-induced up-regulation of adiponectin in liversteatosis remains unelucidated. Thus, we tested whether GRb1 ameliorates liver steatosis and insulinresistance by promoting the expression of adiponectin. Methods: 3T3-L1 adipocytes and hepatocytes were used to investigate GRb1's action on adiponectinexpression and triglyceride (TG) accumulation. Wild type (WT) mice and adiponectin knockout (KO)mice fed high fat diet were treated with GRb1 for 2 weeks. Hepatic fat accumulation and function as wellas insulin sensitivity was measured. The activation of AMPK was also detected in the liver andhepatocytes. Results: GRb1 reversed the reduction of adiponectin secretion in adipocytes. The conditioned medium(CM) from adipocytes treated with GRb1 reduced TG accumulation in hepatocytes, which was partlyattenuated by the adiponectin antibody. In the KO mice, the GRb1-induced significant decrease of TGcontent, ALT and AST was blocked by the deletion of adiponectin. The elevations of GRb1-induced insulinsensitivity indicated by OGTT, ITT and HOMA-IR were also weakened in the KO mice. The CM treatmentsignificantly enhanced the phosphorylation of AMPK in hepatocytes, but not GRb1 treatment. Likewise,the phosphorylation of AMPK in liver of the WT mice was increased by GRb1, but not in the KO mice. Conclusions: The up-regulation of adiponectin by GRb1 contributes to the amelioration of liver steatosisand insulin resistance, which further elucidates a new mechanism underlying the beneficial effects ofGRb1 on obesity

심포지움 초록 - Ⅲ ( 국제인삼심포지움 , 1992년 8월 10-14 , 장춘 , 중국 ) ( Abstracts - Ⅲ ( '92 International Ginseng Symposium , August 10-14 , 1992 , Changchun , China )

Liu Ping,Zhang Wei,Ge YingChun,Zhang Shuchen 고려인삼학회 1993 Journal of Ginseng Research Vol.17 No.2

Seismic performance of RC columns retrofitted using high-strength steel strips under high axial compression ratios

Yong Yang,Ning Hao,Yicong Xue,Shiqiang Feng,Yunlong Yu,Shuchen Zhang 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.84 No.3

In this paper, the impact on seismic performance of an economical effective technique for retrofitting reinforced concrete (RC) columns using high-strength steel strips under high axial compression ratios was presented. The experimental program included a series of cyclic loading tests on one nonretrofitted control specimen and three retrofitted specimens. The effects of the axial compression ratio and spacing of the steel strips on the cyclic behavior of the specimens were studied. Based on the test results, the failure modes, hysteretic characteristics, strength and stiffness degradation, displacement ductility, and energy dissipation capacity of the specimens were analyzed in-depth. The analysis showed that the transverse confinement provided by the high-strength steel strips could effectively delay and restrain diagonal crack development and improve the failure mode, which was flexural-shear failure controlled by flexural failure with better ductility. The specimens retrofitted using high-strength steel strips showed more satisfactory seismic performance than the control specimen. The seismic performance and deformation capacity of the retrofitted RC columns increased with decreasing axial compression ratio and steel strip spacing. Based on the test results, a hysteretic model for RC columns that considers the transverse confinement of high-strength steel strips was then established. The hysteretic model showed good agreement with the experimental results, which verified the effectiveness of the proposed hysteretic model. Therefore, the aforementioned analysis can be used for the design of retrofitted RC columns.

Zebrafish Dnd protein binds to 3`UTR of geminin mRNA and regulates its expression

( Shu Chen ),( Mei Zeng ),( Hua Qin Sun ),( Wen Qian Deng ),( Yi Lu Lu ),( Da Chang Tao ),( Yun Qiang Liu ),( Si Zhong Zhang ),( Yong Xin Ma ) 생화학분자생물학회 (구 한국생화학분자생물학회) 2010 BMB Reports Vol.43 No.6

Dnd (dead end) gene encodes an RNA binding protein and is specifically expressed in primordial germ cells (PGCs) as a vertebrate-specific component of the germ plasma throughout embryogenesis. By utilizing a technique of specific nucleic acids associated with proteins (SNAAP), 13 potential target mRNAs of zebrafish Dnd (ZDnd) protein were identified from 8-cell embryo, and 8 target mRNAs have been confirmed using an RT-PCR analysis. Of the target mRNAs, the present study is focused on the regulation of geminin, which is an inhibitor of DNA replication. Using electrophoretic mobility shift assay (EMSA), we demonstrated that ZDND protein bound the 67-nucleotide region from 864 to 931 in the 3`UTR of geminin mRNA, a sequence containing 60.29% of uridine. Results from a dual-luciferase assay in HEK293 cells showed that ZDND increases the translation of geminin. Taken together, the identification of target mRNA for ZDnd will be helpful to further explore the biological function of Dnd in zebrafish germ-line development as well as in cancer cells. [BMB reports 2010; 43(6): 438-444]