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Chen, Z.,Qiu, L.,Tian, Y.,Lee, Y. I.,Hou, X.,Wu, L. Royal Society of Chemistry 2017 Analytical methods Vol.9 No.21
<P>We developed a surface-enhanced Raman scattering (SERS)-active substrate based on chemical vapor deposition (CVD)-grown monolayer graphene-encapsulated silver nanoparticles (Ag NPs) and used it for the detection of 2,4,6-trinitrotoluene (TNT). Monolayer graphene-encapsulated Ag NPs can be used as a stable substrate for up to 2 months under aerobic exposure. The single layer of graphene can effectively stabilize the Ag NPs against oxidation and corrosion in the presence of H2O2, Na2S and HNO3. Due to the combination of the Ag NPs with graphene, the Raman signals of probe molecules were dramatically enhanced. This platform exhibits extraordinarily high sensitivity and excellent stability for the detection of TNT, with a limit of detection as low as 6.6 x 10(-10) mol L-1. This work provides a simple approach to fabricate graphene-encapsulated Ag NPs for sensitive SERS sensing of TNT after Fenton oxidation degradation.</P>
Zheng, Y.,Chen, Z.,Zheng, C.,Lee, Y.I.,Hou, X.,Wu, L.,Tian, Y. Pergamon Press ; Elsevier Science Ltd 2016 Talanta Vol.155 No.-
<P>A facile method was developed for determination of trace volatile acetone by coupling a derivatization reaction to surface-enhanced Raman scattering (SERS). With iodide modified Ag nanoparticles (Ag IMNPs) as the SERS substrate, acetone without obvious Raman signal could be converted to SERS-sensitive species via a chemical derivatization reaction with 2,4-dinitrophenylhydrazine (2,4-DNPH). In addition, acetone can be effectively separated from liquid phase with a purge-sampling device and then any serious interference from sample matrices can be significantly reduced. The optimal conditions for the derivatization reaction and the SERS analysis were investigated in detail, and the selectivity and reproducibility of this method were also evaluated. Under the optimal conditions, the limit of detection (LOD) for acetone was 5 mg L-1 or 0.09 mM (3 sigma). The relative standard deviation (RSD) for 80 mg L-1 acetone (n=9) was 1.7%. This method was successfully used for the determination of acetone in artificial urine and human urine samples with spiked recoveries ranging from 92% to 110%. The present method is convenient, sensitive, selective, reliable and suitable for analysis of trace acetone, and it could have a promising clinical application in early diabetes diagnosis. (C) 2016 Elsevier B.V. All rights reserved.</P>
Shang, L.,Tian, P-Y.,Kim, N-J.,Chang, H. N.,Hahm, M. S. VCH VERLAGSGESELLSCHAFT 2009 CHEMICAL ENGINEERING AND TECHNOLOGY Vol.32 No.4
<P>Recombinant Escherichia coli has been studied as a main host for recombinant protein productions, but it is still difficult to cultivate E. coli in a large industrial-scale process due to the oxygen supply limitation. In this study, E. coli BL(21) harboring a new constructed plasmid (pEHUb-hGH) was used for producing recombinant human growth hormone (r-hGH) in 5-L and 30-L scale fermentors by supplying air and high purity oxygen, respectively, where the high purity oxygen was produced from a vacuum pressure swing adsorption (PSA). The impact of oxygen supply modes, i.e., air and high purity oxygen, on cell growth and r-hGH production was investigated in different scale fermentors. In the case of high purity oxygen supply, the final cell density and r-hGH concentrations were 63.0 and 4.8 g/L in the 5-L fermentor, 51.6 and 4.0 g/L in the 30-L fermentor, respectively. In addition, the productivity of r-hGH was doubled in the 5-L fermentor, and increased 4-fold in the 30-L fermentor, compared to the results obtained in the case of the air supply. The supply of high purity oxygen eliminated the oxygen limitation and acetate formation effectively, and apparently, did not affect the degradation of r-hGH. This shows that the recombinant E. coli cultivation with high purity oxygen produced from PSA may provide an effective method for large-scale industrial production of recombinant proteins.</P> <B>Graphic Abstract</B> <P>In the fed-batch culture of E. coli BL(21) for producing recombinant human growth hormone (r-hGH), the cell growth and r-hGH production are seen to be significantly improved by supplying high purity oxygen. This demonstrates that supplying high purity oxygen may be effective for carrying out large-scale, high cell density aerobic cultures. <img src='wiley_img/09307516-2009-32-4-CEAT200800481-content.gif' alt='wiley_img/09307516-2009-32-4-CEAT200800481-content'> </P>
Tian, D.,Liu, B.,Zhang, L.,Wang, X.,Zhang, W.,Han, L.,Park, D.W. Korean Society of Industrial and Engineering Chemi 2012 Journal of industrial and engineering chemistry Vol.18 No.4
Four novel bifunctional aluminum-salen complexes (2a, 2b, 2c, and 2d) containing both Lewis acidic metal center and Lewis base quaternary phosphonium salt sites within one molecule and an aluminum-salen complex with a neutral tert-butyl group (2f) for comparison were synthesized and characterized by UV-vis, IR, <SUP>1</SUP>H, <SUP>13</SUP>C, <SUP>27</SUP>Al NMR spectroscopy and Elemental analysis (EA). Their catalytic efficiencies as single-component catalysts toward the coupling reaction of carbon dioxide and propylene oxide were evaluated. These complexes exhibit catalytic activity in the order 2d>2a>2b>2c@?2f. <SUP>27</SUP>Al NMR spectra reveal the existence of five- and six-coordinated metal centers in the aluminum-salen complexes bearing a quaternary phosphonium salt group, whereas only five-coordinate aluminum species were found in the aluminum-salen complex with a neutral tert-butyl group. This indicates the importance of the six-coordinate aluminum center in enhancing the catalytic activity as well as an intramolecular cooperative effect in bifunctional aluminum-salen complexes 2a-d. The effects of reaction variables on the catalytic performance were investigated in detail. These new catalysts are highly stable to moisture and air and robust to impurities in the coupling reaction.
Pan, L.,Zhao, P.F.,Yang, Z.Y.,Long, S.F.,Wang, H.L.,Tian, Q.Y.,Xu, Y.T.,Xu, X.,Zhang, Z.H.,Piao, X.S. Asian Australasian Association of Animal Productio 2016 Animal Bioscience Vol.29 No.12
Two experiments were conducted to evaluate effects of coated compound proteases (CC protease) on apparent total tract digestibility (ATTD) of nitrogen (N) and energy, and apparent ileal digestibility (AID) of amino acids (AA) and nutrients in diets for pigs. In Exp. 1, 12 crossbred barrows (initial body weight: $20.79{\pm}1.94kg$) were housed in individual metabolism crates and allotted into 2 treatments with 6 piglets per treatment according to weight in a randomized complete block design. The 2 diets were corn-soybean meal basal diets with (0.2 g/kg) or without CC protease supplementation. The CC protease supplementation increased (p<0.05) the digestible and metabolizable N and energy values and the digestibility and retention rate of N in the diet. The ATTD of energy and nutrients had been improved (p<0.05) in the diet supplemented with CC protease. In Exp. 2, 12 crossbred barrows (initial body weight: $20.79{\pm}1.94kg$), fitted with T-cannulas at the distal ileum, were blocked by body weight into 2 groups with 6 pigs each. The diets were the same as those in Exp. 1. The CC protease increased (p<0.05) the AID of crude protein and some essential AA including arginine, isoleucine and leucine. The AID and ATTD of energy and nutrients had been improved (p<0.05) by supplemental CC protease, but the hindgut digestibility of nutrients was unaffected. Overall, the CC protease improved the ATTD of N and energy and AID of some indispensible AA and nutrients in the corn-soybean meal diet for pigs. Therefore, the CC protease supplement could improve the utilization of protein in the corn-soybean meal diet and thus contribute to lower N excretion to the environment.
Nano-Layer Structure of Silicon-on-Insulator Materials
X Wang,x Wang,J Chen,L. L. Tian,M Chen,P He,X. H. Liu,Y. M. Dong,Z. L. Liu 한국물리학회 2003 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.42 No.III
Silicon-on-insulator (SOI) has been recognized as a promising semiconductor starting material for ICs where high speed and low power consumption are desirable, in addition to its unique applications in radiation-hardened circuits. In the present paper, three novel SOI nano-layer structures have been demonstrated. ULTRA-THIN SOI has been fabricated by separation by implantation of oxygen (SIMOX) technique at low oxygen ion energy of 45 keV and implantation dosage of 1.8´1017/cm2. The formed SOI layer is uniform with thickness of only 60 nm. This layer is of crystalline quality, and the interface between this layer and the buried oxide layer is very sharp. PATTERNED SOI nano-structure is illustrated by source and drain on insulator (DSOI) MOSFETs. The DSOI structure has been formed by selective oxygen ion implantation in SIMOX process. With the patterned SOI technology, the floating-body effect and self-heating effect, which occur in the conventional SOI devices, are significantly suppressed. In order to improve the total-dose irradiation hardness of SOI devices, SILICON ON INSULATING MULTILAYERS (SOIM) nano-structure is proposed. The buried insulating multilayers, which are composed of SiO$_x$ and SiN$_y$ layers, have been realized by implantation of nitride and oxygen ions into silicon in turn at different ion energies, followed by two steps of high temperature annealing process, respectively. Electric property investigation shows that the hardness to the total-dose irradiation of SOIM is remarkably superior to those of the conventional SIMOX SOI and the Bond-and-Etch-Back SOI.