Chromatographic Behavior of Proteins on Stationary Phase with Aminocarboxy Ligand

Rong Li,Ming-Yang Ju,Bin Chen,Qing-Yuan Sun,Guo-Liang Chen,Mei Shi,Xiao-Gang Wang,Jian-Bin Zheng 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.2

An aminocarboxy aspartic acid-bonded silica (Asp-Silica) stationary phase was synthesized using L-aspartic acid as ligand and silica gel as matrix. The standard protein mixtures were separated with prepared chromatographic column. The effects of solution pH, salt concentration and metal ion on the retention of proteins were examined, and also compared with traditional iminodiacetic acid-bonded silica (IDA-Silica) column. The results show that Asp-Silica column exhibited an excellent separation performance for proteins. The retention of proteins on Asp-Silica stationary phase was consistent with electrostatic characteristic of cation-exchange. The stationary phase displayed typical metal chelate property after fixing copper ion (II) on Asp-Silica. Under competitive eluting condition, protein mixtures were effectively isolated. Asp ligand showed better ion-exchange and metal chelating properties as compared with IDA ligand.

Spatial Correlation-based Resource Sharing in Cognitive Radio SWIPT Networks

Mei Rong,Zhonghua Liang 한국인터넷정보학회 2022 KSII Transactions on Internet and Information Syst Vol.16 No.9

Cognitive radio-simultaneous wireless information and power transfer (CR-SWIPT) has attracted much interest since it can improve both the spectrum and energy efficiency of wireless networks. This paper focuses on the resource sharing between a point-to-point primary system (PRS) and a multiuser multi-antenna cellular cognitive radio system (CRS) containing a large number of cognitive users (CUs). The resource sharing optimization problem is formulated by jointly scheduling CUs and adjusting the transmit power at the cognitive base station (CBS). The effect of accessing CUs’ spatial channel correlation on the possible transmit power of the CBS is investigated. Accordingly, we provide a low-complexity suboptimal approach termed the semi-correlated semi-orthogonal user selection (SC-SOUS) algorithm to enhance the spectrum efficiency. In the proposed algorithm, CUs that are highly correlated to the information decoding primary receiver (IPR) and mutually near orthogonal are selected for simultaneous transmission to reduce the interference to the IPR and increase the sum rate of the CRS. We further develop a spatial correlation-based resource sharing (SC-RS) strategy to improve energy sharing performance. CUs nearly orthogonal to the energy harvesting primary receiver (EPR) are chosen as candidates for user selection. Therefore, the EPR can harvest more energy from the CBS so that the energy utilization of the network can improve. Besides, zero-forcing precoding and power control are adopted to eliminate interference within the CRS and meet the transmit power constraints. Simulation results and analysis show that, compared with the existing CU selection methods, the proposed low-complex strategy can enhance both the achievable sum rate of the CRS and the energy sharing capability of the network.

Synthesis and Chromatographic Characteristics of Multidentate Ligand-Boned Silica Stationary Phases

Rong Li,Yan Wang,Guo-Liang Chen,Mei Shi,Xiao-Gang Wang,Jian-Bin Zheng 대한화학회 2010 Bulletin of the Korean Chemical Society Vol.31 No.8

To improve the separation property and stability of metal chelate Cu(II) column, three new kinds of multidentate aminocarboxy silica columns with cation-exchange properties were synthesized using glutamic acid (Glu), glutamic acidbromoacetic acid (Glu-BAA), glutamic acid-bromosuccinic acid (Glu-BSUA) as ligands and silica gel as matrix. The standard proteins were separated with prepared chromatographic columns. The stationary phases exhibited the metal chelate property after fixing copper ion (II) on the synthesized multidentate ligand silica columns. The binding capacity of immobilized metal ion was related with the dentate number of multidentate ligands. Chromatographic behavior of proteins and the leakage of immobilized metal ion on multidentate chelate Cu(II) columns were affected by the dentate number of multidentate ligands and competitive elution system directly. The results showed that quinquedentate Glu-BSUA-Cu(II) column exhibited better chromatographic property and stability as compared with tridentate Glu-Cu(II) column, tetradentate Glu-BAA-Cu(II) column and commonly used IDA-Cu(II) column.

Molecular Characterization and Tissue Distribution of Estrogen Receptor Genes in Domestic Yak

Fu, Mei,Xiong, Xian-Rong,Lan, Dao-Liang,Li, Jian Asian Australasian Association of Animal Productio 2014 Animal Bioscience Vol.27 No.12

Estrogen and its receptors are essential hormones for normal reproductive function in males and females during developmental stage. To better understand the effect of estrogen receptor (ER) gene in yak (Bos grunniens), reverse transcription-polymerase chain reaction (PCR) was carried out to clone $ER{\alpha}$ and $ER{\beta}$ genes. Bioinformatics methods were used to analyze the evolutionary relationship between yaks and other species, and real-time PCR was performed to identify the mRNA expression of $ER{\alpha}$ and $ER{\beta}$. Sequence analysis showed that the ER open reading frames (ORFs) encoded 596 and 527 amino acid proteins. The yak $ER{\alpha}$ and $ER{\beta}$ shared 45.3% to 99.5% and 53.9% to 99.1% protein sequence identities with other species homologs, respectively. Real-time PCR analysis revealed that $ER{\alpha}$ and $ER{\beta}$ were expressed in a variety of tissues, but the expression level of $ER{\alpha}$ was higher than that of $ER{\beta}$ in all tissues, except testis. The mRNA expression of $ER{\alpha}$ was highest in the mammary gland, followed by uterus, oviduct, and ovary, and lowest in the liver, kidney, lung, testis, spleen, and heart. The $ER{\beta}$ mRNA level was highest in the ovary; intermediary in the uterus and oviduct; and lowest in the heart, liver, spleen, lung, kidney, mammary gland, and testis. The identification and tissue distribution of ER genes in yaks provides a foundation for the further study on their biological functions.

Biochemical Characterization of a GDSL-Motif Esterase from Bacillus sp. K91 with a New Putative Catalytic Mechanism

( Jun Mei Ding ),( Ting Ting Yu ),( Lian Ming Liang ),( Zhen Rong Xie ),( Yun Juan Yang ),( Jun Pei Zhou ),( Bo Xu ),( Jun Jun Li ),( Zun Xi Huang ) 한국미생물 · 생명공학회 2014 Journal of microbiology and biotechnology Vol.24 No.11

The esterase gene Est8 from the thermophilic bacterium Bacillus sp. K91 was cloned and expressed in Escherichia coli. The monomeric enzyme exhibited a theoretical molecular mass of 24.5 kDa and an optimal activity around 50°C at pH 9.0. A model of Est8 was constructed using a hypothetical YxiM precursor structure (2O14_A) from Bacillus subtilis as template. The structure showed an α/β-hydrolase fold and indicated the presence of a typical catalytic triad consisting of Ser-11, Asp-182, and His-185, which were investigated by site directed replacements coupled with kinetic characterization. Asp-182 and His-185 residues were more critical than the Ser-11 residue in the catalytic activity of Est8. A comparison of the amino acid sequence showed that Est8 could be grouped into the GDSL family and further classified as an SGNH hydrolase. Est8 is a new member of the SGNH hydrolase subfamily and may employ a different catalytic mechanism.

Synthesis and Chromatographic Characteristics of Multidentate Ligand-Boned Silica Stationary Phases

Li, Rong,Wang, Yan,Chen, Guo-Liang,Shi, Mei,Wang, Xiao-Gang,Zheng, Jian-Bin Korean Chemical Society 2010 Bulletin of the Korean Chemical Society Vol.31 No.8

To improve the separation property and stability of metal chelate Cu(II) column, three new kinds of multidentate aminocarboxy silica columns with cation-exchange properties were synthesized using glutamic acid (Glu), glutamic acidbromoacetic acid (Glu-BAA), glutamic acid-bromosuccinic acid (Glu-BSUA) as ligands and silica gel as matrix. The standard proteins were separated with prepared chromatographic columns. The stationary phases exhibited the metal chelate property after fixing copper ion (II) on the synthesized multidentate ligand silica columns. The binding capacity of immobilized metal ion was related with the dentate number of multidentate ligands. Chromatographic behavior of proteins and the leakage of immobilized metal ion on multidentate chelate Cu(II) columns were affected by the dentate number of multidentate ligands and competitive elution system directly. The results showed that quinquedentate Glu-BSUA-Cu(II) column exhibited better chromatographic property and stability as compared with tridentate Glu-Cu(II) column, tetradentate Glu-BAA-Cu(II) column and commonly used IDA-Cu(II) column.

Chromatographic Behavior of Proteins on Stationary Phase with Aminocarboxy Ligand

Li, Rong,Ju, Ming-Yang,Chen, Bin,Sun, Qing-Yuan,Chen, Guo-Liang,Shi, Mei,Wang, Xiao-Gang,Zheng, Jian-Bin Korean Chemical Society 2011 Bulletin of the Korean Chemical Society Vol.32 No.2

An aminocarboxy aspartic acid-bonded silica (Asp-Silica) stationary phase was synthesized using L-aspartic acid as ligand and silica gel as matrix. The standard protein mixtures were separated with prepared chromatographic column. The effects of solution pH, salt concentration and metal ion on the retention of proteins were examined, and also compared with traditional iminodiacetic acid-bonded silica (IDA-Silica) column. The results show that Asp-Silica column exhibited an excellent separation performance for proteins. The retention of proteins on Asp-Silica stationary phase was consistent with electrostatic characteristic of cation-exchange. The stationary phase displayed typical metal chelate property after fixing copper ion (II) on Asp-Silica. Under competitive eluting condition, protein mixtures were effectively isolated. Asp ligand showed better ion-exchange and metal chelating properties as compared with IDA ligand.

Clinical Efficacy of Bevacizumab Concomitant with Pemetrexed in Patients with Advanced Non-small Cell Lung Cancer

Zhang, Yu-Mei,Li, Yong-Qiang,Liu, Zhi-Hui,Liao, Xiao-Li,Liang, Rong,Lin, Yan,Yuan, Chun-Ling,Liao, Si-Na,Liang, Chao-Yong,Li, Qian,Li, Le-Qun Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.8

Objective: To observe the clinical efficacy of bevacizumab concomitant with pemetrexed in patients with advanced non-small cell lung cancer (NSCLC). Materials and Methods: A total of 72 patients were randomly divided into a combination group (pemetrexed+bevacizumab, n=36) and a pemetrexed group (n=36) and assessed for disease control (CR+PR+SD) after 4-cycles of first-line GP chemotherapy (gemcitabine+cisplatin). Clinical efficacy, progression-free survival time (PFS), overall survival time (OS), overall response rate (ORR), disease control rate (DCR) and rate of adverse responses between two groups were observed and compared. Results: ORR and DCR were 27.8% and 83.4% in combination group, and 16.7% and 69.5% in the pemetrexed group, respectively, but there were no significant differences (P>0.05). PFS in combination group and pemetrexed group were 4.6 months and 3.9 months respectively (P=0.09), whereas OS in the combination group was 14 months, evidently higher than in the pemetrexed group (11 months, P=0.004). Adverse responses in both groups included high blood pressure, bleeding, thrombocytopenia, anemia, elevated transaminase, diarrhea, vomiting and proteinuria, but there were no significant differences (P>0.05). Conclusions: Bevacizumab concomitant with pemetrexed has better clinical efficacy and safety, giving rise to prolonged survival time in patients with advanced NSCLC.

Microwave-assisted functionalization of polyurethane surface for improving blood compatibility

Deqiang You,Mei Tu,Rong Zeng,Hao Liang,Weizhong Mai,Jianhao Zhao,Zhengang Zha 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.5

In order to improve the hemocompatibility of polyurethane (PU), we report a rapid and efficient two-step approach to graft poly(ethylene glycol) (PEG) onto PU surface by a microwave-assisted method,involving diphenylmethane diisocyanate (MDI) – functionalization and subsequent PEG coupling. Compared with conventional heating, the effects of solvent, time and MDI concentrations on the microwave-assisted MDI-functionalization, and the effect of time on the microwave-assisted PEG coupling were studied. PEGs with different molecular weights were successfully grafted onto PU surface under the optimum microwave-assisted conditions within only 20 min, and characterized by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and chemical titration. The hydrophilicity and in vitro blood compatibility of the surfaces were evaluated by water contact angle measurements, blood coagulation time (whole blood clotting time and prothrombin time) and platelet adhesion tests, respectively. All the PU-PEG surfaces had improved surface wettability and hemocompatibility. The results suggested that microwave-assisted functionalization may be a promising method for rapidly and effectively decorating polyurethane surfaces.

Structural and optical investigation of GaN grown by metal-organic Chemical Vapor Deposition

Xiao-Yong Gao,Liang-Yao Chen,Jing Li,Peng Zhou,Rong-Jun Zhang,Song-You Wang,Yue-Mei Yang,Yu-Xiang Zheng 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.44 No.32

Structural and optical properties of GaN grown on (0001)-oriented sapphire substrates by low pressure metal-organic chemical vapor deposition were investigated by XRD, ellipsometry, PL and other optical methods. The thickness of the GaN sample was about 1.5 m. Seen by XRD, the existence of the strong (0002) diraction peak with a very narrow FWHM value of 0.1 and the high order GaN (0004) diraction peak conrms a good quality of the GaN lms grown on sapphire substrate by using a multi-step growth procedure. Optical transparency of the GaN samples induces strong interference oscillations below E0 (3.44eV) in the measured dielectric function spectra and re ective spectra. In low temperature PL spectra, the red shift of the peak and decreased intensity of PL are visible. The former can be attributed to the involvement of band tail states, and the latter can be accounted for by the decreasing non-radiative recombination lifetime.