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Shen, Qiuwan,Zheng, Ying,Luo, Cong,Zheng, Chuguang Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.6
Perovskite-type oxides are promising oxygen carriers in producing oxygen-enriched $CO_2$ gas stream for oxyfuel combustion. In this study, a new series of $SrCo_{1-x}Fe_xO_{3-{\delta}}$ (x = 0.2, 0.4, 0.6, 0.8) was prepared and used to produce $O_2/CO_2$ mixture gas. The phase, crystal structure, and morphological properties of $SrCo_{1-x}Fe_xO_{3-{\delta}}$ were investigated through X-ray diffraction, specific surface area measurements, and environmental scanning electron microscopy. The oxygen desorption performance of $SrCo_{1-x}Fe_xO_{3-{\delta}}$ was studied in a fixed-bed reactor system. Results showed that the different x values of $SrCo_{1-x}Fe_xO_{3-{\delta}}$ have no obvious effects on crystalline structure. However, the oxygen desorption performance of $SrCo_{1-x}Fe_xO_{3-{\delta}}$ is improved by Co doping. Moreover, $SrCo_{0.8}Fe_{0.2}O_{3-{\delta}}$ synthesized via a new EDTA method has a larger BET surface area ($40.396m^2/g$), smaller particle size (48.3 nm), and better oxygen production performance compared with that synthesized through a liquid citrate method.
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China`s Peaceful Development and Asia-Pacific Security
( Shen Xia Zheng ) 한국국방연구원 2006 The Korean Journal of Defense Analysis Vol.18 No.4
The rapid emergence of a large country like China understandably will cause some international concern and suspicions. However, China has decided to take the road of peaceful development, and has committed itself to building a harmonious world China persists in mutual benefits and collective development, while pursuing its own prosperity. China advocates the establishment of a democratic and fair world order when it merges itself into the world and abides by the established international norms. China cannot develop peacefully without a favorable periphery and international environment. Among the three elements, common security is the objective that all players in the region should seek. Cooperation security is the approach that all countries have to adapt in an era of globalization. Development security is the foundation. It promotes the prosperity of each individual country so as to eliminate the roots of insecurity. The following five goals should be pursued by China and other countries to preserve win-win benefits for all: Increasing Strategic Mutual Trust Between the Countries; Joining Hands to Maintain Cross-Taiwan Strait Peace and Stability; Striving For a Peaceful Solution of the DPRK Nuclear Issue; Promoting Regional Security Cooperation; and Enhancing Regional Cooperation in Areas Other Than Security.
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Mei Shen,Zhi-Qiang Liu,Yu-Guo Zheng,Yin-Chu Shen 한국생물공학회 2009 Biotechnology and Bioprocess Engineering Vol.14 No.6
The medium components of nitrilase production by Arthrobacter nitroguajacolicus ZJUTB06-99 were optimized in this study. Effects of factors such as carbon sources, nitrogen sources, and inducers on nitrilase production were investigated. Glucose, yeast extract, and ε-caprolactam were chosen as the suitable components. Moreover, experiments were carried out to fix the concentration of three factors for the zero coded level of variables in the subsequent optimization. Response surface methodology (RSM) and central composite design (CCD) were employed for further optimization. A quadratic model was found to fit the nitrilase activity and the variables. The results revealed that the optimized medium contained (%, w/v) 2.80, glucose; 0.57, yeast extract; and 0.42, ε-caprolactam. Validation experiments were carried out under the optimized conditions and nitrilase activity of 107.49 U/L was close to the predicted activity 110.82 U/L. After optimization, the nitrilase activity attained 2.86 fold of activity compared to the unoptimized conditions and the conversion of acrylonitrile was significantly improved. The strain growth curve and nitrilase activity alteration in the course of culture were tested. The cells were suitably harvested after cultured for 72~78 h The medium components of nitrilase production by Arthrobacter nitroguajacolicus ZJUTB06-99 were optimized in this study. Effects of factors such as carbon sources, nitrogen sources, and inducers on nitrilase production were investigated. Glucose, yeast extract, and ε-caprolactam were chosen as the suitable components. Moreover, experiments were carried out to fix the concentration of three factors for the zero coded level of variables in the subsequent optimization. Response surface methodology (RSM) and central composite design (CCD) were employed for further optimization. A quadratic model was found to fit the nitrilase activity and the variables. The results revealed that the optimized medium contained (%, w/v) 2.80, glucose; 0.57, yeast extract; and 0.42, ε-caprolactam. Validation experiments were carried out under the optimized conditions and nitrilase activity of 107.49 U/L was close to the predicted activity 110.82 U/L. After optimization, the nitrilase activity attained 2.86 fold of activity compared to the unoptimized conditions and the conversion of acrylonitrile was significantly improved. The strain growth curve and nitrilase activity alteration in the course of culture were tested. The cells were suitably harvested after cultured for 72~78 h
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CRISPR as a strong gene editing tool
( Shengfu Shen ),( Tiing Jen Loh ),( Hongling Shen ),( Xuexiu Zheng ),( Haihong Shen ) 생화학분자생물학회 2017 BMB Reports Vol.50 No.1
Clustered regularly-interspaced short palindromic repeats (CRISPR) is a new and effective genetic editing tool. CRISPR was initially found in bacteria to protect it from virus invasions. In the first step, specific DNA strands of virus are identified by guide RNA that is composed of crRNA and tracrRNA. Then RNAse III is required for producing crRNA from pre-crRNA. In The second step, a crRNA:tracrRNA:Cas9 complex guides RNase III to cleave target DNA. After cleavage of DNA by CRISPR-Cas9, DNA can be fixed by Non- Homologous End Joining (NHEJ) and Homology Directed Repair (HDR). Whereas NHEJ is simple and random, HDR is much more complex and accurate. Gene editing by CRISPR is able to be applied to various biological field such as agriculture and treating genetic diseases in human. [BMB Reports 2017; 50(1): 20-24]
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Qiuwan Shen,Ying Zheng,Cong Luo,Chuguang Zheng 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.6
Perovskite-type oxides are promising oxygen carriers in producing oxygen-enriched CO2 gas stream for oxyfuel combustion. In this study, a new series of SrCo1-xFexO3-δ (x = 0.2, 0.4, 0.6, 0.8) was prepared and used to produce O2/CO2 mixture gas. The phase, crystal structure, and morphological properties of SrCo1-xFexO3-δ were investigated through X-ray diffraction, specific surface area measurements, and environmental scanning electron microscopy. The oxygen desorption performance of SrCo1-xFexO3-δ was studied in a fixed-bed reactor system. Results showed that the different x values of SrCo1-xFexO3-δ have no obvious effects on crystalline structure. However, the oxygen desorption performance of SrCo1-xFexO3-δ is improved by Co doping. Moreover, SrCo0.8Fe0.2O3-δ synthesized via a new EDTA method has a larger BET surface area (40.396 m2/g), smaller particle size (48.3 nm), and better oxygen production performance compared with that synthesized through a liquid citrate method.
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Xiaolei Zheng,Qun Wang,Xiaoqiang Li,Changkuan Zheng,Chenjie Shen 한양대학교 청정에너지연구소 2023 Journal of Ceramic Processing Research Vol.24 No.5
Surface modification of powder materials has always been a key issue that must be faced to improve their applicationproperties and application value. Herein, an efficient and eco-friendly CH4/CF4 plasma method is used for surface modificationof materials. The surface modification mechanism of fluorocarbon plasma under different gas flow ratios was detailedinvestigated by combining the kinetic analysis. The findings demonstrate that fluorocarbon plasma exhibits differentmodification mechanisms under different modification conditions. The physicochemical properties of the material surface canbe easily controlled by adjusting the ratio of fluorocarbon plasma. Functional CaTiO3 particles with core-shell structure weresuccessfully prepared when the gas flow rate ratio R=3. The modified surface exhibited extreme hydrophobicity and the lowestsurface energy. This strong application of fluorocarbon plasma technology in material surface modification offers a newavenue to prepare environmentally friendly and functional powders.
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Zheng, Chun-Long,Qiu, Chen,Shen, Mei-Xiao,Qu, Xiao,Zhang, Tie-Hong,Zhang, Ji-Hong,Du, Jia-Jun Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.5
Background: The vascular endothelial growth factor family has been implicated in tumorigenesis and metastasis. The prognostic value of each vascular endothelial growth factor family member, particular VEGF/VEGFR co-expression, in patients with non-small lung cancer remains controversial. Materials and Methods: Relevant literature was identified by searching PubMed, EMBASE and Web of Science. Studies evaluating expression of VEGFs and/or VEGFRs by immunohistochemistry or ELISA in lung cancer tissue were eligible for inclusion. Hazard ratios (HRs) and 95% confidence intervals (CIs) from individual study were pooled by using a fixed- or random-effect model, heterogeneity and publication bias analyses were also performed. Results: 74 studies covering 7,631 patients were included in the meta-analysis. Regarding pro-angiogenesis factors, the expression of VEGFA (HR=1.633, 95%CI: 1.490-1.791) and VEGFR1 (HR=1.924, 95%CI: 1.220-3.034) was associated separately with poor survival. Especially, VEGFA over-expression was an independent prognostic factor in adenocarcinoma (ADC) (HR=1.775, 95%CI: 1.384-2.275) and SCC (HR=2.919, 95%CI: 2.060-4.137). Co-expression of VEGFA/VEGFR2 (HR=2.011, 95%CI: 1.405-2.876) was also significantly associated with worse survival. For lymphangiogenesis factors, the expression of VEGFC (HR=1.611, 95%CI: 1.407-1.844) predicted a poor prognosis. Co-expression of VEGFC/VEGFR3 (HR=2.436, 95%CI: 1.468-4.043) emerged as a preferable prognostic marker. Conclusions: The expression of VEGFA (particularly in SCC and early stage NSCLC), VEGFC, VEGFR1 indicates separately an unfavorable prognosis in patients with NSCLC. Co-expression VEGFA/VEGFR2 is comparable with VEGFC/VEGFR3, both featuring sufficient discrimination value as preferable as prognostic biologic markers.
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CXCL12-CXCR4 Promotes Proliferation and Invasion of Pancreatic Cancer Cells
Shen, Bo,Zheng, Ma-Qing,Lu, Jian-Wei,Jiang, Qian,Wang, Tai-Hong,Huang, Xin-En Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.9
Objective: CXCL12 exerts a wide variety of chemotactic effects on cells. Evidence indicates that CXCL12, in conjunction with its receptor, CXCR4, promotes invasion and metastasis of tumor cells. Our objective was to explore whether the CXCL12-CXCR4 biological axis might influence biological behavior of pancreatic cancer cells. Methods: Miapaca-2 human pancreatic cancer cells were cultured under three different conditions: normal medium (control), medium + recombinant CXCL12 (CXCL12 group), or medium + CXCR4-inhibitor AMD3100 (AMD3100 group). RT-PCR was applied to detect mRNA expression levels of CXCL12, CXCR4, matrix metalloproteinase 2 (MMP-2), MMP-9, and human urokinase plasminogen activator (uPA). Additionally, cell proliferation and invasion were performed using CCK-8 colorimetry and transwell invasion assays, respectively. Results: CXCL12 was not expressed in Miapaca-2 cells, but CXCR4 was detected, indicating that these cells are capable of receiving signals from CXCL12. Expression of extracellular matrix-degrading enzymes MMP-2, MMP-9, and uPA was upregulated in cells exposed to exogenous CXCL12 (P<0.05). Additionally, both proliferation and invasion of pancreatic cancer cells were enhanced in the presence of exogenous CXCL12, but AMD3100 intervention effectively inhibited these processes (P<0.05). Conclusions: The CXCL12-CXCR4 biological axis plays an important role in promoting proliferation and invasion of pancreatic cancer cells.
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