A Novel Non-phosgene Approach to the Synthesis of Methyl N-phenyl Carbamate by a Reaction of Methanol with Phenylurea

Shi-run Yan,Xin-kui Wang,Zhen-hua Li,Kang-nian Fan,Mao-qing Kang,Shao-yi Peng 한국화학공학회 2004 Korean Journal of Chemical Engineering Vol.21 No.2

A novel non-phosgene process for the synthesis of methyl N-phenyl carbamate (MPC) by a reaction of phenylurea with methanol was studied. The reaction between phenylurea and methanol was found to be a spontaneous reaction that took place in the absence of catalyst and gave MPC as the main product. Addition of a catalyst markedly influenced the reaction behavior. A basic catalyst greatly enhanced the yield of MPC, whereas an acidic catalyst promoted the formation of aniline and methyl carbamate. Moderate strength of basicity showed the best catalytic performance in the cases studied. The mechanism of reaction and catalyst functioning was discussed.

Movement of Rhizobia Inside Tobacco and Lifestyle Alternation from Endophytes to Free-Living Rhizobia on Leaves

( Kui Xian Ji ),( Feng Chi ),( Ming Feng Yang ),( Shi Hua Shen ),( Yu Xiang Jing ),( Frank B. Dazzo ),( Hai Ping Cheng ) 한국미생물 · 생명공학회 2010 Journal of microbiology and biotechnology Vol.20 No.2

Systematic Analysis on the GSTM1 Null Phenotype and Prostate Cancer Risk in Chinese People

Shi, Jing,Zhuang, Yan,Liu, Yan,Yan, Cheng-Quan,Liu, Xian-Kui,Zhang, Ying Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.5

Objective: Glutathione S-transferase M 1 (GSTM1) is implicated as a risk factor for prostate cancer. However, this issue is not clear in Chinese population. This systemic analysis was conducted to evaluate the effect of GSTM1 null genotypes on prostate cancer risk in Chinese. Methods: Published studies investigating the associations between GSTM1 null genotypes and the risk of prostate cancer in China were identified by using a predefined search strategy. Main statisticals were pooled and estimated according to the primarily reported data. Results: The prevalence of the GSTM1 null genotype was higher in prostate cancer patients than in controls, with significance. Conclusion: The GSTM1 null genotypes is associated with increased risk of prostate cancer in Chinese.

Real option consumption-utility based indifference pricing under stochastic volatility

Feng Shi,Jinqiang Yang,Kui Ma 인하대학교 정석물류통상연구원 2009 인하대학교 정석물류통상연구원 학술대회 Vol.2009 No.10

This paper deals with the consumption-utility based indifference pricing problem of real option under stochastic volatility by analyzing a mixed optimal control and optimal stopping problem under an incomplete market. Implied option value is given by the solution to a two dimensional free-boundary PDE and the numerical results are obtained by the finite difference method. The numerical analysis illustrates that stochastic volatility will increase the implied option value and encourage the agent exericse the option later. Additionally, the stochastic volatility results in more consumption and decreases the precautionary savings motive of the agent. And an increase in the risk aversion attituede raises those effects.

Fluorine-Substituted Dithienylbenzodiimide-Based n-Type Polymer Semiconductors for Organic Thin-Film Transistors

Feng, Kui,Zhang, Xianhe,Wu, Ziang,Shi, Yongqiang,Su, Mengyao,Yang, Kun,Wang, Yang,Sun, Huiliang,Min, Jie,Zhang, Yujie,Cheng, Xing,Woo, Han Young,Guo, Xugang American Chemical Society 2019 ACS APPLIED MATERIALS & INTERFACES Vol.11 No.39

<P>Imide functionalization is one of the most effective approaches to develop electron-deficient building blocks for constructing n-type organic semiconductors. Driven by the attractive properties of imide-functionalized dithienylbenzodiimide (TBDI) and the promising device performance of TBDI-based polymers, a novel acceptor with increased electron affinity, fluorinated dithienylbenzodiimide (TFBDI), was designed with the hydrogen replaced by fluorine on the benzene core, and the synthetic challenges associated with this highly electron-deficient fluorinated imide building block are successfully overcome. TFBDI showed suppressed frontier molecular orbital energy levels as compared with TBDI. Copolymerizing this new electron-withdrawing TBDI with various donor co-units afforded a series of n-type polymer semiconductors TFBDI-T, TFBDI-Se, and TFBDI-BSe. All these TFBDI-based polymers exhibited a lower-lying lowest unoccupied molecular orbital (LUMO) energy level than the polymer analogue without fluorine. When applied in organic thin-film transistors, three polymers showed unipolar electron transport with large on-current/off-current ratios (<I>I</I><SUB>on</SUB>/<I>I</I><SUB>off</SUB>) of 10<SUP>5</SUP>-10<SUP>7</SUP>. Among them, the selenophene-based polymer TFBDI-Se with the deepest-positioned LUMO and optimal chain stacking exhibited the highest electron mobility of 0.30 cm<SUP>2</SUP> V<SUP>-1</SUP> s<SUP>-1</SUP>. This result demonstrates that the new TFBDI is a highly attractive electron-deficient unit for enabling n-type polymer semiconductors, and the fluorination of imide-functionalized arenes offers an effective approach to develop more electron-deficient building blocks in organic electronics.</P> [FIG OMISSION]</BR>

Muscle-derived Stem Cells Differentiate into Functional Smooth Muscle Cells for Ureter Tissue Engineering: An Experimental Study

Zhan-Kui Zhao,Hong-Lian Yu,Fei Xiao,Shi-Wen Li,Wen-Biao Liao,Kai-Liang Zhao 한국생물공학회 2012 Biotechnology and Bioprocess Engineering Vol.17 No.3

We assessed the ability of muscle-derived stem cells (MDSC) to differentiate into smooth muscle cells (SMC) and their potential to promote the regeneration of smooth muscle with a vessel extracellular matrix (VECM)for tissue engineering of the ureter. MDSC were isolated,proliferated, and identified by flow cytometry. SMC phenotype differentiation was induced with a smooth muscle induction medium. Gene expression was evaluated by real-time quantitative polymerase chain reaction (PCR)and Western blot studies. The VECM was obtained by a decellularization process, and cytotoxic effects were evaluated by exposing the induced cells to a VECM extract. The induced cells were seeded onto VECM in vitro for 1 week, and then the compound grafts were used for ureter reconstitution in vivo. The grafts were obtained for histological studies at 2, 4, 8, and 16 weeks post-operation. Intravenous urography was used to evaluate renal function and ureteral patency. Flow cytometry demonstrated that the MDSC expressed Sca-1 and desmin, but did not express CD45. After induction, SMC phenotype gene expression was confirmed in the induced cells by real-time quantitative PCR and Western blot studies. VECM exhibited a nontoxic effect on the induced cells in vitro. At 16 weeks postoperation,a histological evaluation showed that multilayered urothelium and organized muscle fiber bundles had formed in the grafts. Intravenous urography demonstrated no evidence of ureteral stricture or hydroureteronephrosis. These results demonstrate that MDSC can be induced into SMC and that this was useful for promoting regeneration of smooth muscles for ureter tissue engineering. We assessed the ability of muscle-derived stem cells (MDSC) to differentiate into smooth muscle cells (SMC) and their potential to promote the regeneration of smooth muscle with a vessel extracellular matrix (VECM)for tissue engineering of the ureter. MDSC were isolated,proliferated, and identified by flow cytometry. SMC phenotype differentiation was induced with a smooth muscle induction medium. Gene expression was evaluated by real-time quantitative polymerase chain reaction (PCR)and Western blot studies. The VECM was obtained by a decellularization process, and cytotoxic effects were evaluated by exposing the induced cells to a VECM extract. The induced cells were seeded onto VECM in vitro for 1 week, and then the compound grafts were used for ureter reconstitution in vivo. The grafts were obtained for histological studies at 2, 4, 8, and 16 weeks post-operation. Intravenous urography was used to evaluate renal function and ureteral patency. Flow cytometry demonstrated that the MDSC expressed Sca-1 and desmin, but did not express CD45. After induction, SMC phenotype gene expression was confirmed in the induced cells by real-time quantitative PCR and Western blot studies. VECM exhibited a nontoxic effect on the induced cells in vitro. At 16 weeks postoperation,a histological evaluation showed that multilayered urothelium and organized muscle fiber bundles had formed in the grafts. Intravenous urography demonstrated no evidence of ureteral stricture or hydroureteronephrosis. These results demonstrate that MDSC can be induced into SMC and that this was useful for promoting regeneration of smooth muscles for ureter tissue engineering.

Preparation of isotropic spinnable pitch and carbon fiber from biomass tar through the co-carbonization with ethylene bottom oil

Jianxiao Yang,Kui Shi,Xuanke Li,Seong-Ho Yoon 한국탄소학회 2018 Carbon Letters Vol.25 No.-

In this study, we tried to prepare an isotropic spinnable pitch which can be useful to prepare the general purpose carbon fiber through the co-carbonization of biomass tar with ethylene bottom oil under two different preparation methods (atmospheric distillation, pressurized distillation). The results showed that the ethylene bottom oil added co-carbonization was very effective to decrease of the oxygen contents for obtaining a stable spinnable pitch. The pressurized distillation was more effective to reduce the oxygen functional groups of pitches than atmospheric distillation. The obtained spinnable pitch by the pressurized distillation showed higher pitch yield of 42% and lower oxygen content of 9.12% than the spinnable pitch by the atmospheric distillation. The carbon fiber derived from the pressurized distillation spinnable pitch by carbonization at 800ºC for 5 min showed that the higher tensile strength of carbon fiber was increased up to 800 MPa.

A Novel Non-phosgene Approach to the Synthesis of Methyl N-phenyl Carbamate by a Reaction of Methanol with Phenylurea

Wang, Xin-kui,Yan, Shi-run,Li, Zhen-hua,Fan, Kang-nian,Kang, Mao-qing,Peng, Shao-yi 한국화학공학회 2004 Korean Journal of Chemical Engineering Vol.21 No.2

A novel non-phosgene process for the synthesis of methyl N-phenyl carbamate (MPC) by a reaction of phenylurea with methanol was studied. The reaction between phenylurea and methanol was found to be a spontaneous reaction that took place in the absence of catalyst and gave MPC as the main product. Addition of a catalyst markedly influenced the reaction behavior. A basic catalyst greatly enhanced the yield of MPC, whereas an acidic catalyst promoted the formation of aniline and methyl carbamate. Moderate strength of basicity showed the best catalytic performance in the cases studied. The mechanism of reaction and catalyst functioning was discussed.

Preparation and Gene Delivery of Alkaline Amino Acids-Based Cationic Liposomes

Li, Li,Nie, Yu,Zhu, Rong,Shi, Sanjun,Luo, Kui,He, Bin,Yang, Yang,Yang, Junxiao,Gu, Zhongwei 대한약학회 2008 Archives of Pharmacal Research Vol.31 No.7

Cationic lipids 1, 2, and 3, based on hydrophobic cholesterol linked to L-lysine, L-histidine or Larginine, respectively, were designed and tested as gene delivery vectors. Physicochemical and biological properties of all liposomes and lipoplexes were evaluated, including lipid-DNA interactions, size, morphology, zeta potential, acid-base buffering capability, protection of DNA from DNase I digestion, and cytotoxity. The efficiency of luciferase gene transfection of lipoplexes 1-3 was compared with that of commercial dioleoyl-trimethylammonium propane (DOTAP) and polyethyleneimine (PEI) in 293T cells and HepG2 cells with or without poly(ethylene glycol) PEG stabilizer. The complexation and protection of DNA of liposome 3 was the strongest among the three liposomes. The efficiency of gene transfection of liposomes 1-3 was two-to threefold higher than that of PEI and/or DOTAP in 293T cells. Liposomes 1 and 3 in PEG as stabilizer showed sixfold higher transfection efficiency than that of PEI and/or DOTAP, whereas liposome 2 showed very low transfection efficiency. In HepG2 cells, the transfection efficiency of all the cationic liposomes was much lower than that of DOTAP. In conclusion, lipids 1-3 were efficient and non-toxic gene vectors; the headgroup of cationic lipids and the stabilizer of liposome formulation had an important influence on gene transfection.

Effect of anion species on preparation and properties of pitch-based activated carbon fibers by in-situ catalytic activation of metal nanoparticles

Gou Genchang,Wei Wenjie,Yang Jianxiao,Liu Jiahao,Liu Yue,Li Jun,Shi Kui 한국탄소학회 2022 Carbon Letters Vol.32 No.6

The pitch-based activated carbon fibers (ACFs) were prepared from ethylene tar-derived pitches containing nickelocene (CNi) or nickel nitrate (NiN). The effects of different anions and contents of metal salts on the microstructure and surface chemical properties of fibers were investigated. The results revealed that Ni2+ from CNi mainly remained its pristine molecule in the organometal salt-derived pitch (OP-xCNi), while Ni2+ from NiN occurred complexation reaction with polycyclic aromatic hydrocarbons (PAHs) in the inorganic metal salt-derived pitch (IP-xNiN) due to the weaker binding ability between anions and Ni2+ of CNi than CNi. The XRD and SEM results confirmed that IP-3NiN-ACF contained Ni, NiO, Ni2O3 nanoparticles with different size distributions, while OP-3CNi-ACF only contained more uniformly distributed Ni nanoparticles with small size. Furthermore, OP-3.0CNi-ACF presented higher specific surface area of 1862 m2/g and a pore volume of 1.69 cm3/g than those of IP-3.0NiN-ACF due to the formation of pore structure during the in-situ catalytic activation of different metal nanoparticles. Therefore, this work further pointed out that the desired pore structure and surface chemistry of pitch-based ACFs could be obtained through regulating and controlling the interaction of anion species, metal cations and PAHs during the synthesis of pitch precursors.