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Zhang T.,TU Munich | Zhang T.,State Key Laboratory of Bioelectronics | Troll C.,TU Munich | Rieger B.,TU Munich | And 3 more authors.
Journal of Catalysis | Year: 2010

An improved procedure, three-step reaction cycle procedure, for the continuous preparation of phosgene from CO, air and HCl catalyzed by CuCl2 was reported for the first time. The corresponding catalytic mechanism of each step was preliminarily disclosed with the powder X-ray diffraction (XRD) analysis: the first step is the oxychlorination of CO to phosgene and simultaneous reduction of CuCl2 to CuCl; the second step is the oxidation of CuCl with air to Cu2OCl2, and the third step is the neutralization of Cu2OCl2 with HCl to CuCl2. The regeneration of catalyst consists of steps 2 and 3, which is called the two-step regeneration of catalyst. The no-simultaneous existence of Cu (I) chloride and water in this three-step reaction procedure prevented effectively copper (I) chloride from the disproportionation. The influence of regeneration conditions, including reaction time, pressure of air or HCl on morphologies and recovery degree of catalyst were investigated and discussed. The degree of recovery for the single-run yield and cumulative yield of phosgene from the two-step regenerated oxychlorination agent can reach, respectively, 87.0% and 97.0% whereas the single-run yield and cumulative yield of phosgene with the one-step regenerated catalyst only can be recovered to 58.8% and 80.5%, respectively. The two-step regeneration method also can result in a higher dispersion of CuCl2/KCl on silica gel than that of the one-step regeneration. These results not only can offer a quite promising potential for the industrial use, but also can promote our deeply understanding of this important industrial reaction. © 2009 Elsevier Inc. All rights reserved. Source


Lin X.,Nanjing Southeast University | Lin X.,State Key Laboratory of Bioelectronics | Li Y.,Tianjin Medical University | Gu N.,Nanjing Southeast University | Gu N.,State Key Laboratory of Bioelectronics
Soft Matter | Year: 2011

We have performed coarse grained molecular dynamics simulations (CGMD) to investigate the interactions of generation 7, 5 and 3 (G7, G5 and G3) charge-neutral polyamidoamine (PAMAM) dendrimers with a DPPC (dipalmitoylphosphatidylcholine) monolayer at the air-water interface (model pulmonary surfactant) during the end-expiration process. Our results show that different generations of PAMAM dendrimers have different influences on the DPPC monolayer. Generally, G3 PAMAM dendrimers show little influence on the DPPC monolayer's structure and relative properties. While G7 and G5 PAMAM dendrimers tend to induce the formation of largely deformed structures of the DPPC monolayer and inhibit or even reverse the normal phase transition of the interfacial DPPC molecules during the process of compression. Besides, we find that the formation processes of these disrupted structures are energy-favorable based on analyzing van der Waals interaction energy between PAMAM dendrimers and the whole system. © The Royal Society of Chemistry 2011. Source


Huang R.,State Key Laboratory of Bioelectronics | Xi Z.,State Key Laboratory of Bioelectronics | He N.,State Key Laboratory of Bioelectronics
Science China Chemistry | Year: 2015

Since aptamer and its in vitro selection process called SELEX were independently described by Ellington and Gold in 1990, extensive research has been undertaken and numerous isolated aptamers for various targets have been applied. Aptamers can bind to a wide range of targets that include small organic molecules, inorganic compounds, haptens and even whole cells with high binding affinity and specificity. Aptamers for wide range of targets have been selected currently. In addition, aptamers are thermo stable and can also be regenerated easily within a few minutes denaturation, which makes them easy to store or handle. These advantages make aptamers extremely suitable for applications based on molecular recognition as analytical, diagnostic and therapeutic tools. In this review, the recent applications of aptamers for chemistry analysis, medicine and food security, along with the future trend will be discussed. © 2015 Science China Press and Springer-Verlag Berlin Heidelberg Source


Ji X.,State Key Laboratory of Bioelectronics | Yang W.,Jiangsu University | Wang T.,State Key Laboratory of Bioelectronics | Mao C.,Nanjing Normal University | And 4 more authors.
Journal of Biomedical Nanotechnology | Year: 2013

Biodegradable core/shell structured poly(L-lactide) acid (PLLA)/chitosan (CS) nanofibers were fabricated by coaxial electrospinning. PLLA and CS were dissolved in dichloromethane and aqueous acetic acid solvents for spinning into core and shell layers, respectively. CS of high molecular weight was difficult to spin into nanofibers by electrospinning due to its high viscosity, but it was easier to achieve by coaxial electrospinning with PLLA. The preparation conditions were optimized by changing the ratios of PLLA/CS under different jet voltages. After being investigated by scanning electron microscope (SEM), a smooth structure was prepared using 2% CS as the shell solution with applied voltage 15 kV. Transmission electron microscopy (TEM) study and infrared spectrometry (IR) characterization of PLLA/CS nanofibers indicated that the core/shell structure was successfully fabricated. Brunauer-Emmett-Teller (BET) surface area and pore size distribution exhibited higher capacity of PLLA/CS than PLLA used as drug carrier in tissue engineering. The cytocompatibility of nanofibers were evaluated by co-cultured with human bone marrow-derived UE7T-13 cells, the 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT) test exhibited good proliferation of PLLA/CS for cells. Results of blood compatibility tests showed decreased hemolytic ratio and platelets adhesion of PLLA/CS compared with PLLA. The results indicated that PLLA/CS nanofibers could be potential drug carrier for tissue engineering. Copyright © 2013 American Scientific Publishers All rights reserved. Source


Ji X.,State Key Laboratory of Bioelectronics | Wang T.,State Key Laboratory of Bioelectronics | Guo L.,State Key Laboratory of Bioelectronics | Xiao J.,Nanjing Medical University | And 7 more authors.
Journal of Biomedical Nanotechnology | Year: 2013

Poly(L-lactide) acid (PLLA) was mixed with different content of nanoscale-ZnO (N-ZnO) and spun into nonwoven mats by electrospinning, the effects of the blending ratio of N-ZnO on mats morphology and mechanical properties were investigated. The prepared mats were characterized with infrared spectrometry (IR), Brunauer-Emmett-Teller (BET) surface area, the morphology and tensile test were investigated by scanning electron microscope (SEM) and electronic universal testing machine, respectively. The quantity of N-ZnO contained in mats was determinated by Na2 EDTA titration method, then the N-ZnO loading coefficient (%, NL) could be figured out. Infrared spectrometry showed that the electrospun PLLA/N-ZnO mats were prepared successfully. When the concentration of N-ZnO contained in the mats increased from 0 to 2% (w/v), the curves of stress-strain indicated that the elastic modulus of mats ranged among 5.16 to 15.59 MPa. In addition, the electrospun PLLA/N-ZnO exhibited lower cell proliferation for UE7T-13 cells than electrospun PLLA mats and control. The results presented that the N-ZnO added in the mats enhanced the toughness of PLLA/ZnO mats to some extent, though the biocompatibility of blends was not good. Copyright © 2013 American Scientific Publishers All rights reserved. Source

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