Zeta-potentials of Oxygen and Nitrogen Enriched Activated Carbons for Removal of Copper Ion

Kwan-Ho Park,Chang-Ho Lee,Seung-Kon Ryu,Xiaoping Yang 한국탄소학회 2007 Carbon Letters Vol.8 No.4

The oxygen and nitrogen enriched activated carbons were obtained from modification of commercial activated carbon by using nitric acid, sodium hydroxide and urea. Zeta-potentials of modified activated carbons were investigated in relation to copper ion adsorption. The structural properties of modified activated carbons were not so much changed, but the zeta-potentials and isoelectric points were considerably changed. The zeta-potential of nitric acid modified activated carbon was the most negative than other activated carbons in the entire pH region, and the pHIEP was shifted from pH 4.8 to 2.6, resulted in the largest copper ion adsorption capacities compare with other activated carbons in the range of pH 3~6.5. In case of urea modified activated carbon, copper ion adsorption was larger than that of the as-received activated carbon from pH 2 to pH 6.5 even though the pHIEP was shifted to pH 6.0, it was due to the coordination process operated between nitrogen functional groups and copper ion. The adsorption capacity of copper ion was much influenced by zeta-potential and pHIEP of carbon adsorbent.

Zeta-potentials of Oxygen and Nitrogen Enriched Activated Carbons for Removal of Copper Ion

Park, Kwan-Ho,Lee, Chang-Ho,Ryu, Seung-Kon,Yang, Xiaoping Korean Carbon Society 2007 Carbon Letters Vol.8 No.4

The oxygen and nitrogen enriched activated carbons were obtained from modification of commercial activated carbon by using nitric acid, sodium hydroxide and urea. Zeta-potentials of modified activated carbons were investigated in relation to copper ion adsorption. The structural properties of modified activated carbons were not so much changed, but the zeta-potentials and isoelectric points were considerably changed. The zeta-potential of nitric acid modified activated carbon was the most negative than other activated carbons in the entire pH region, and the $pH_{IEP}$ was shifted from pH 4.8 to 2.6, resulted in the largest copper ion adsorption capacities compare with other activated carbons in the range of pH 3~6.5. In case of urea modified activated carbon, copper ion adsorption was larger than that of the as-received activated carbon from pH 2 to pH 6.5 even though the $pH_{IEP}$ was shifted to pH 6.0, it was due to the coordination process operated between nitrogen functional groups and copper ion. The adsorption capacity of copper ion was much influenced by zeta-potential and $pH_{IEP}$ of carbon adsorbent.

Absolute Molecular Weight Determination of Sodium Salt of Methacrylic Acid/Acrylic Acid-2-Isooctyl Ester/2-Acrylamido-2-Methylpropanesulfonic Acid Terpolymer by GPC/MALLS

Xiaoping Chang,Zequan Liu,Qiang Zhang 대한화학회 2016 Bulletin of the Korean Chemical Society Vol.37 No.12

The samples of sodium salt of methacrylic acid/acrylic acid-2-isooctyl ester/2-acrylamido-2-methylpropanesulfonic acid terpolymer (SSMAA) were synthesized by free radical solution polymerization. The absolute weight-average molar mass (Mw) and polydispersity (Mw /Mn ) of the polymers were successfully determined using aqueous-based gel permeation chromatography coupled with multiangle laser light scattering. The results show that mixed solutions of highly concentrated buffered salt (NaNO3 or NaCl and NaH2PO4 ) and organic solvent modifier (methanol) are needed to eliminate the undesirable interactions between polymer and polymer, and between polymer and stationary phase. Dynamic light scattering was first used to investigate the aggregation behavior of SSMAA in a variety of potential mobile phase compositions and screen the optimum compositions. The Mw and Mw /Mn values of the three samples prepared with different amount of initiator are 13500, 5820, and 2490 g/mol and 1.52, 1.45, and 1.47, respectively.

Fluorescent squaramides as anion receptors and transmembrane anion transporters

Bao, Xiaoping,Wu, Xin,Berry, Stuart N.,Howe, Ethan N. W.,Chang, Young-Tae,Gale, Philip A. The Royal Society of Chemistry 2018 Chemical communications Vol.54 No.11

<P>A series of squaramide-based anion transporters functionalised with the 1,8-naphthalimide fluorophore has been developed for improved ionophoric activity and fluorescent imaging in cells.</P>

An innovative liquid metal-based pressure sensor with its application in geotechnical engineering

Yundong Shou,Xiaoping Zhou,Qingpeng Chang,Chao Liu 국제구조공학회 2021 Smart Structures and Systems, An International Jou Vol.27 No.1

In this paper, a monitoring system containing a novel liquid metal-based pressure sensor and remote interactive monitoring devices are fabricated to monitor stress in geotechnical engineering. The pressure sensor with the dimension of 34 mm × 34 mm is designed and manufactured, which is mainly composed of 40CrMoV alloy steel shell, polydimethylsiloxane (PDMS) and liquid metal gallium indium alloy (EGaIn). It has the characteristics of high stability, can greatly improve the measurement range of the pressure sensor (0 to 20 MPa), and its resistance variation is from 0 mΩ to 800 mΩ. In addition, the linear regression analysis is carried out to verify the linear relationship between the resistance of sensor and the applied pressure. It is found that the performance of the pressure sensor is fine through experiments with three different loading rates and fatigue experiments. The remote interactive monitoring device can be suitable for the field monitoring environment, which is composed of monitoring stations (MS), remote communication base stations (RCBS) and indoor working platform. Finally, the monitoring system is successfully applied to the field measurements in geotechnical engineering, and the field monitoring data are in good agreement with the numerical results.

Identification of drug target candidates of the swine pathogen Actinobacillus pleuropneumoniae by construction of protein–protein interaction network

Siqi Li,Zhipeng Su,Chengjun Zhang,Zhuofei Xu,Xiaoping Chang,Jiawen Zhu,Ran Xiao,Lu Li,Rui Zhou 한국유전학회 2018 Genes & Genomics Vol.40 No.8

Porcine pleuropneumonia caused by Actinobacillus pleuropneumoniae has led to severe economic losses in the pig industry worldwide. A. pleuropneumoniae displays various levels of antimicrobial resistance, leading to the dire need to identify new drug targets. Protein–protein interaction (PPI) network can aid the identification of drug targets by discovering essential proteins during the life of bacteria. The aim of this study is to identify drug target candidates of A. pleuropneumoniae from essential proteins in PPI network. The homologous protein mapping method (HPM) was utilized to construct A. pleuropneumoniae PPI network. Afterwards, the subnetwork centered with H-NS was selected to verify the PPI network using bacterial two-hybrid assays. Drug target candidates were identified from the hub proteins by analyzing the topology of the network using interaction degree and homologous comparison with the pig proteome. An A. pleuropneumoniae PPI network containing 2737 non-redundant interaction pairs among 533 proteins was constructed. These proteins were distributed in 21 COG functional categories and 28 KEGG metabolic pathways. The A. pleuropneumoniae PPI network was scale free and the similar topological tendencies were found when compared with other bacteria PPI network. Furthermore, 56.3% of the H-NS subnetwork interactions were validated. 57 highly connected proteins (hub proteins) were identified from the A. pleuropneumoniae PPI network. Finally, 9 potential drug targets were identified from the hub proteins, with no homologs in swine. This study provides drug target candidates, which are promising for further investigations to explore lead compounds against A. pleuropneumoniae.

[ $T_2$ ]-relaxation Time Measurement of ex vivo $^1H$ MR Metabolite Peaks for Evaluation of Human Stomach Cancer

Mun Chi-Woong,Choi Ki-Sueng,Shin Oon-Jae,Yang Young-Ill,Chang Hee-Kyung,Hu Xiaoping,Eun Chung-Ki The Korean Society of Medical and Biological Engin 2006 의공학회지 Vol.27 No.2

In this study, transverse relaxation time (T2) measurement and the evaluation of the characteristics of the spectral peak related to stomach tissue metabolites were performed using ex vivo proton magnetic resonance spectroscopic imaging (MRSI) at 1.5-T MRI/S instruments. Thirty-two gastric tissues resected from 12 patients during gastric cancer surgery, of which 19 were normal tissue and 13 were cancerous tissue, were used to measure the $T_2$ of the magnetic resonance spectroscopy (MRS) peaks. The volume of interest data results from the MRSI measurements were extracted from the proper muscle (MUS) layer and the composite mucosa/submucosa (MC/SMC) layer and were statistically analyzed. MR spectra were acquired using the chemical shift imaging (CSI) point resolved spectroscopy (CSI-PRESS) technique with the parameters of pulse repetition time (TR) and echo times (TE) TR/(TE1,TE2)=1500 msec/(35 msec, 144 msec), matrix $size=24{\times}24$, NA=1, and voxel $size=2.2{\times}2.2{\times}4mm^3$. In conclusion, the measured $T_2$ of the metabolite peaks, such as choline (3.21ppm) and lipid (1.33ppm), were significantly decreased (p<0.01 and p<0.05, respectively) in the cancerous stomach tissue.

Escherichia coli-Derived Outer Membrane Vesicles Deliver Galactose- 1-Phosphate Uridyltransferase and Yield Partial Protection against Actinobacillus pleuropneumoniae in Mice

( Keji Quan ),( Zhuang Zhu ),( Sanjie Cao ),( Fei Zhang ),( Chang Miao ),( Xintian Wen ),( Xiaobo Huang ),( Yiping Wen ),( Rui Wu ),( Qigui Yan ),( Yong Huang ),( Xiaoping Ma ),( Xinfeng Han ),( Qin Z 한국미생물 · 생명공학회 2018 Journal of microbiology and biotechnology Vol.28 No.12

In our previous studies, we have identified several in vivo-induced antigens and evaluated their potential as subunit vaccine candidates in a murine model, in which the recombinant protein GalT showed the most potent immunogenicity and immunoprotective efficacy against Actinobacillus pleuropneumoniae. To exploit a more efficient way of delivering GalT proteins, in this study, we employed the widely studied E. coli outer membrane vesicles (OMVs) as a platform to deliver GalT protein and performed the vaccine trial using the recombinant GalTOMVs in the murine model. Results revealed that GalT-OMVs could elicit a highly-specific, IgG antibody titer that was comparable with the adjuvant GalT group. Significantly higher lymphocyte proliferation and cytokines secretion levels were observed in the GalT-OMVs group. 87.5% and 50% of mice were protected from a lethal dose challenge using A. pleuropneumoniae in active or passive immunization, respectively. Histopathologic and immunohistochemical analyses showed remarkably reduced pathological changes and infiltration of neutrophils in the lungs of mice immunized with GalT-OMVs after the challenge. Taken together, these findings confirm that OMVs can be used as a platform to deliver GalT protein and enhance its immunogenicity to induce both humoral and cellular immune responses in mice.

인체의 위 조직 시료에서 자기공명영상장치를 이용한 확산계수 측정에 대한 기초 연구

문치웅,최기승,양영일,장희경,은충기,Mun Chi-Woong,Choi, Ki-Sueng,Nana Roger,Hu, Xiaoping P.,Yang, Young-Il,Chang Hee-Kyung,Eun, Choong-Ki 대한의용생체공학회 2006 의공학회지 Vol.27 No.5

The aim of this study is to investigate the feasibility of ex vivo MR diffusion tensor imaging technique in order to observe the diffusion-contrast characteristics of human gastric tissues. On normal and pathologic gastric tissues, which have been fixed in a polycarbonate plastic tube filled with 10% formalin solution, laboratory made 3D diffusion tensor Turbo FLASH pulse sequence was used to obtain high resolution MR images with voxel size of $0.5{\times}0.5{\times}0.5mm^3\;using\;64{\times}32{\times}32mm^3$ field of view in conjunction with an acquisition matrix of $128{\times}64{\times}64$. Diffusion weighted- gradient pulses were employed with b values of 0 and $600s/mm^2$ in 6 orientations. The sequence was implemented on a clinical 3.0-T MRI scanner(Siemens, Erlangen, Germany) with a home-made quadrature-typed birdcage Tx/Rx rf coil for small specimen. Diffusion tensor values in each pixel were calculated using linear algebra and singular value decomposition(SVD) algorithm. Apparent diffusion coefficient(ADC) and fractional anisotropy(FA) map were also obtained from diffusion tensor data to compare pixel intensities between normal and abnormal gastric tissues. The processing software was developed by authors using Visual C++(Microsoft, WA, U.S.A.) and mathematical/statistical library of GNUwin32(Free Software Foundation). This study shows that 3D diffusion tensor Turbo FLASH sequence is useful to resolve fine micro-structures of gastric tissue and both ADC and FA values in normal gastric tissue are higher than those in abnormal tissue. Authors expect that this study also represents another possibility of gastric carcinoma detection by visualizing diffusion characteristics of proton spins in the gastric tissues.