Amperometric Determination of Nitrite at Poly(Methylene Blue)-Modified Glassy Carbon Electrode

Xu, Guang-Ri,Xu, Guifang,Xu, Ming-Lu,Zhang, Zhengqing,Tian, Yuan,Choi, Han-Nim,Lee, Won-Yong Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.2

Electrochemical characteristics of nitrite ion were investigated at a poly(methylene blue)-modified glassy carbon electrode by cyclic voltammetry and differential pulse voltammetry. The poly(methylene blue)-modified glassy carbon electrode exhibited enhanced anodic signals for nitrite. The effects of key parameters on the detection of nitrite were evaluated at the modified electrode, such as pH, accumulation time, and scan rate. Under optimum condition, the chemically modified electrode can detect nitrite in the concentration range $2.0{\times}10^{-6}$ to $5.0{\times}10^{-4}$ M with the detection limit of $2.0{\times}10^{-6}$ M and a correlation coefficient of 0.999. The detection of nitrite using the chemically modified electrode was not affected by common ions such as $Na^+$, $K^+$, $Ca^{2+}$, $Cl^-$, $HPO_4^{2-}$ and $H_2PO_4^- $. The modified electrode showed good stability and reproducibility. The practical application of the present method was successfully applied to the determination of nitrite ion in cabbage samples.

SiC particulate reinforced aluminum matrix composite coatings prepared by laser powder deposition

Xu Xiang-yang,Han Jian-min,Li Wei-jing,Liu Yuan-fu,Liu Long-mei 한양대학교 세라믹연구소 2006 Journal of Ceramic Processing Research Vol.7 No.2

A SiC particulate reinforced aluminum matrix composite coatings for wear resistance improvement were investigated. Laser powder deposition processing was optimized, the microstructure of the coatings was analyzed, and the wear resistance of the coatings was evaluated. Under optimized processing, a laser powder deposited coating is free of cracks and porosity. SiC particles were uniformly distributed in the coating and well bonded with the matrix. A laser powder deposited coating consists of α-Al, SiC, Al4C3, Si and Al2O3 phases. Due to formation of Al4C3 and Si phases and crystal grain refinement, the wear resistance of laser powder deposited coatings was increased 2.06-3.76 times that of the aluminum alloy substrate based on the high hardness and deformation resistance of the SiC particles.

Single-Source-Precursor Synthesis of Hafnium-Containing Ultrahigh-Temperature Ceramic Nanocomposites (UHTC-NCs)

Yuan, Jia,Hapis, Stefania,Breitzke, Hergen,Xu, Yeping,Fasel, Claudia,Kleebe, Hans-Joachim,Buntkowsky, Gerd,Riedel, Ralf,Ionescu, Emanuel American Chemical Society 2014 Inorganic chemistry Vol.53 No.19

<P>Amorphous SiHfBCN ceramics were prepared from a commercial polysilazane (HTT 1800, AZ-EM), which was modified upon reactions with Hf(NEt<SUB>2</SUB>)<SUB>4</SUB> and BH<SUB>3</SUB>·SMe<SUB>2</SUB>, and subsequently cross-linked and pyrolyzed. The prepared materials were investigated with respect to their chemical and phase composition, by means of spectroscopy techniques (Fourier transform infrared (FTIR), Raman, magic-angle spinning nuclear magnetic resonance (MAS NMR)), as well as X-ray diffraction (XRD) and transmission electron microscopy (TEM). Annealing experiments of the SiHfBCN samples in an inert gas atmosphere (Ar, N<SUB>2</SUB>) at temperatures in the range of 1300–1700 °C showed the conversion of the amorphous materials into nanostructured UHTC-NCs. Depending on the annealing atmosphere, HfC/HfB<SUB>2</SUB>/SiC (annealing in argon) and HfN/Si<SUB>3</SUB>N<SUB>4</SUB>/SiBCN (annealing in nitrogen) nanocomposites were obtained. The results emphasize that the conversion of the single-phase SiHfBCN into UHTC-NCs is thermodynamically controlled, thus allowing for a knowledge-based preparative path toward nanostructured ultrahigh-temperature stable materials with adjusted compositions.</P><P>Amorphous SiHfBCN ceramics were prepared from a suitable single-source precursor. Annealing experiments of the SiHfBCN samples in an inert gas atmosphere at temperatures of 1300−1700 °C led to their conversion nanostructured UHTC-NCs, such as HfC/HfB<SUB>2</SUB>/SiC nanocomposites (in argon) and HfN/Si<SUB>3</SUB>N<SUB>4</SUB>/SiBCN nanocomposites (in nitrogen), thus revealing a convenient preparative approach to nanostructured ultrahigh-temperature stable materials starting from a greatly flexible single-source precursor.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/inocaj/2014/inocaj.2014.53.issue-19/ic501512p/production/images/medium/ic-2014-01512p_0016.gif'></P>

Prognostic Significance of Beclin-1 Expression in Colorectal Cancer: a Meta-analysis

Han, Ye,Xue, Xiao-Feng,Shen, Hu-Gang,Guo, Xiao-Bo,Wang, Xu,Yuan, Bin,Guo, Xing-Po,Kuang, Yu-Ting,Zhi, Qiao-Ming,Zhao, Hong Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.11

Objective: Beclin-1 has recently been observed as an essential marker of autophagy in several cancers. However, the prognostic role of Beclin-1 in colorectal neoplasia remains controversial. Our study aimed to evaluate the potential association between Beclin-1 expression and the outcome of colorectal cancer patients. Materials and Methods: All related studies were systematically searched in Pubmed, Embase, Springer and Chinese National Knowledge Infrastructure databases (CNKI), and then a meta-analysis was performed to determine the association of Beclin-1 expression with clinical outcomes. Finally, a total of 6 articles were included in our analysis. Results: Our data showed that high Beclin-1 expression in patients with CRC was associated with poor prognosis in terms of tumor distant metastasis (OR=2.090, 95%CI=1.061-4.119, p=0.033) and overall survival (RR=1.422, 95%CI=1.032-1.959, p=0.031). However, we did not found any correlation between Beclin-1 over-expression and tumor differentiation (OR=1.711, 95%CI=0.920-3.183, p=0.090). In addition, there was no evidence of publication bias as suggested by Egger's tests for tumor distant metastasis (p=1.000), differentiation (p=1.000) and OS (p=0.308). Conclusions: Our present meta-analysis indicated that elevated Beclin-1 expression iss associated with tumor metastasis and a poor prognosis in patients with CRC. Beclin-1 might serve as an efficient prognostic indicator in CRC, and could be a new molecular target in CRC therapy.

Long non-coding RNA H19X promotes tumorigenesis and metastasis of colorectal cancer through regulating the miR-503-5p/KANK1 axis

Yuan Zihan,Zhao Haizhou,Zhi Qiaoming,Wang Sentai,Liu Chao,Han Ye,Xu Zhihua,Liu Fei,Liu Xingyi,Zan Xinquan,Wang Qiang,Wan Daiwei 한국유전학회 2022 Genes & Genomics Vol.44 No.12

Background: It has been well established that the long non-coding RNAs (lncRNAs) plays a critical role in tumor progression. However, the function of these transcripts and mechanisms responsible for their deregulation in colorectal cancer (CRC) remain to be investigated. Objective: To explore the potential effect and regulation mechanism of lncRNA H19X in colorectal cancer. Methods: We predicted and validated long non-coding RNA H19X from microarray data of colorectal cancer tissues. In addition, the biological behaviors of H19X and miR-503-5p on CRC were examined in vitro and in vivo, including MTT, colony formation assay, Hoechst33342 and transwell assay. The mRNA and protein levels of KN Motif and Ankyrin Repeat Domains 1 (KANK1) were analyzed by Quantitative real-time PCR (qRT-PCR), western blotting (WB) assay. Moreover, bioinformatics tools and dual-luciferase reporter assay were applied to demonstrate the relationship between KANK1 and miR-503-5p. Results: H19X was remarkably up-regulated in CRC tissues. Its expression related to tumor size (p = 0.041), lymph node metastasis (p = 0.037), distal metastasis (p = 0.028), advanced TNM stage (p = 0.034) and poor survival in CRC. H19X acted as an oncogenic lncRNA that induced CRC cell proliferation, invasion and metastasis. Through a number of functional studies, we found that H19X silencing inhibited the malignance phenotype of cancer cells through loss of miR-503-5p. Further studies demonstrated that miR-503-5p was involved in the progression of CRC by directly regulating the downstream target KANK1. Conclusion: Collectively, the findings of the present study indicate H19X/miR-503-5p/KANK1 axis has critical role in the progression of colorectal cancer, providing an effective prognostic indicator and promising target in treatment of colorectal cancer.

Full Dimension MIMO (FD-MIMO): Demonstrating Commercial Feasibility

Xu, Gary,Yang Li,Jin Yuan,Monroe, Robert,Rajagopal, Sridhar,Ramakrishna, Sudhir,Young Han Nam,Ji-Yun Seol,Jaeweon Kim,Gul, Malik Muhammad Usman,Aziz, Ahsan,Jianzhong Zhang IEEE 2017 IEEE journal on selected areas in communications Vol.35 No.8

<P>Massive multi-input multi-output (MIMO) is shown to significantly increase spectral efficiency by exploiting a large number of antennas to support high-order multiuser MIMO. In 3GPP Release-13, a full-dimension MIMO (FD-MIMO) technology was introduced to address practical aspects for massive MIMO in cellular systems; extensive simulations show 2-4 times capacity gain compared with current LTE systems. FD-MIMO has been identified as one of the key 5G technologies and is being continuously improved in 3GPP new radio standards. However, several practical challenges such as interference mitigation among MIMO streams for a large number of users with limited channel feedback, hardware limitations, such as calibration errors that limit the precoding capabilities need to be addressed carefully. A proof of concept (PoC) base-station and user equipment (UE) prototype has been designed to validate the potential of FD-MIMO technology and demonstrate commercial implementation feasibility. In this paper, we present theory and architecture behind an FD-MIMO prototype and share the field test results with LTE-based UEs in a multi-user MIMO setup. We also analyze the impact of transmitter and receiver calibration errors on the performance of the FD-MIMO system.</P>

Engineering the morphology <i>via</i> processing additives in multiple all-polymer solar cells for improved performance

Yuan, Jianyu,Xu, Yalong,Shi, Guozheng,Ling, Xufeng,Ying, Lei,Huang, Fei,Lee, Tack Ho,Woo, Han Young,Kim, Jin Young,Cao, Yong,Ma, Wanli The Royal Society of Chemistry 2018 Journal of materials chemistry. A, Materials for e Vol.6 No.22

<P>In this contribution, we report the working mechanisms of several processing additives for controlling the morphology of four all-polymer systems. The optical and electrical properties, photovoltaic performance, morphology and the dynamic process of film formation of these all-polymer systems were thoroughly examined. We revealed that the effect of additives is largely dependent on the aggregation behaviors of the polymers used. Here, the polymer acceptors with large planar structures have stronger inter-chain interactions, which make their morphology more susceptible to additive treatment compared to the donors. 1,8-Di(R)octane (R = Cl, Br, and I) additives can be applied to multiple all-polymer devices with improved efficiency due to their general capability to increase the crystallinity and extend the effective time during the film formation. Interestingly, DBrO outperforms the widely used DIO, obtaining a highest efficiency of 8.23% for the PTzBI/P(NDI2OD-T2) based all-polymer solar cells, indicating finer morphology control by a subtle change of the additive structure. In contrast, the addition of chloronaphthalene (CN) can alleviate the inter-chain interaction of polymers to prevent the formation of oversized domains, which make it especially efficient for systems using strongly aggregated polymers like P(NDI2OD-T2). Our results provide insight into processing additives and suggest guidelines to rationally select additives for nonfullerene solar cells.</P>

The Genomic Landscape and Clinical Relevance of A-to-I RNA Editing in Human Cancers

Han, L.,Diao, L.,Yu, S.,Xu, X.,Li, J.,Zhang, R.,Yang, Y.,Werner, Henrica M.J.,Eterovic, A.,Yuan, Y.,Li, J.,Nair, N.,Minelli, R.,Tsang, Y.,Cheung, Lydia W.T.,Jeong, K.,Roszik, J.,Ju, Z.,Woodman, Scott Cell Press 2015 CANCER CELL Vol. No.

Adenosine-to-inosine (A-to-I) RNA editing is a widespread post-transcriptional mechanism, but its genomic landscape and clinical relevance in cancer have not been investigated systematically. We characterized the global A-to-I RNA editing profiles of 6,236 patient samples of 17 cancer types from The Cancer Genome Atlas and revealed a striking diversity of altered RNA-editing patterns in tumors relative to normal tissues. We identified an appreciable number of clinically relevant editing events, many of which are in noncoding regions. We experimentally demonstrated the effects of several cross-tumor nonsynonymous RNA editing events on cell viability and provide the evidence that RNA editing could selectively affect drug sensitivity. These results highlight RNA editing as an exciting theme for investigating cancer mechanisms, biomarkers, and treatments.

Hypoglycemic Effects of Glycosaminoglycan from Urechis unicinctus in Diabetic Mice

Chunying Yuan,Ping Liu,Xu Han,Qingman Cui 한국식품영양과학회 2015 Journal of medicinal food Vol.18 No.2

To further utilize glycosaminoglycan from Urechis unicinctus, the hypoglycemic effect and possible mechanism of glycosaminoglycan on diabetic mice were evaluated. Diabetes was induced in mice by intraperitoneal injections of streptozotocin for 3 consecutive days and fed with high-sugar and high-lipid fodder. After diabetes was confirmed, the hypoglycemic effect of glycosaminoglycan from U. unicinctus was investigated in the diabetic mice. Results demonstrated that glycosaminoglycan could significantly decrease blood glucose concentrations, HOMA-IR, AUG, and liver MDA content in diabetic mice. In addition, it significantly enhanced liver SOD and GSH-Px activity, as well as liver GCK activity and hepatic glycogen levels. Glycosaminoglycan from U. unicinctus exhibited efficacy against diabetes, suggesting its potential use as a natural intervention against diabetes.

Molecular Cloning and Function Analysis of an Anthocyanidin Synthase Gene from Ginkgo biloba, and Its Expression in Abiotic Stress Responses

Feng Xu,Hua Cheng,Rong Cai,Lin Ling Li,Jie Chang,Jun Zhu,Feng Xia Zhang,Liu Ji Chen,Yan Wang,Shu Han Cheng,Shui Yuan Cheng 한국분자세포생물학회 2008 Molecules and cells Vol.26 No.6

Anthocyanidin synthase (ANS, leucoanthocyanidin oxygenase), a 2-oxoglutarate iron-dependent oxygenase, catalyzed the penultimate step in the biosynthesis of the anthocyanin class of flavonoids, from the colorless leucoanthocyanidins to the colored anthocyanidins. The full-length cDNA and genomic DNA sequences of ANS gene (designated as GbANS) were isolated from Ginkgo biloba for the first time. The full-length cDNA of GbANS contained a 1062-bp open reading frame (ORF) encoding a 354-amino-acid protein. The genomic DNA analysis showed that GbANS gene had three exons and two introns. The deduced GbANS protein showed high identities to other plant ANSs. The conserved amino acids (H-X-D) ligating ferrous iron and residues (R-X-S) participating in 2-oxoglutarate binding were found in GbANS at the similar positions like other ANSs. Southern blot analysis indicated that GbANS belonged to a multi-gene family. The expression analysis by real-time PCR showed that GbANS expressed in a tissue-specific manner in G. biloba. GbANS was also found to be up-regulated by all of the six tested abiotic stresses, UV-B, abscisic acid, sucrose, salicylic acid, cold and ethylene, consistent with the promoter region analysis of GbANS. The recombinant protein was successfully expressed in E. coli strain with pET-28a vector. The in vitro enzyme activity assay by HPLC indicated that recombinant GbANS protein could catalyze the formation the cyanidin from leucocyanidin and conversion of dihydroquercetin to quercetin, suggesting GbANS is a bifunctional enzyme within the anthocyanidin and flavonol biosynthetic pathway.