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Search Results: 1 - 10 of 18308 matches for " FANG YanFen "
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Mechanism of oxidative damage to DNA by Fe-loaded MCM-41 irradiated with visible light
XiaoXing Wang,Yan Gu,YanFen Fang,YingPing Huang
Chinese Science Bulletin , 2012, DOI: 10.1007/s11434-012-5042-1
Abstract: The mechanism of oxidative damage to deoxyribonucleic acid (DNA) by iron-containing mesoporous molecular sieves (MCM-41) irradiated with visible light was elucidated. Fe-loaded MCM-41 (Fe/MCM-41) was used as a photocatalyst and the damage to calf thymus DNA caused by hydrogen peroxide (H2O2) was studied. The damage and extent of oxidation of DNA were measured by high-performance liquid chromatography (HPLC) and intermediate products were detected by HPLC/electrospray ionization tandem mass spectrometry. Electron spin resonance was used to detect changes in reactive oxygen species and peroxidase catalytic spectrophotometry was used to determine the concentration of H2O2. The results indicated that Fe/MCM-41 efficiently activated H2O2 in solution at pH 4.0–8.0 under irradiation with visible light. The photocatalytic system degraded DNA most effectively at pH 5.0–6.0 but also operated at pH 8.0. At pH 4.2, the degree of DNA damage reached 25.65% after 5 h and the kinetic constant was 5.89×10 2 min 1. Damage to DNA was predominantly caused by hydroxyl radicals generated in the system. The mechanism of DNA damage is of potential concern to human health because it can occur in neutral solutions irradiated by visible light.
CA-125–indicated asymptomatic relapse confers survival benefit to ovarian cancer patients who underwent secondary cytoreduction surgery
Wang Fang,Ye Yanfen,Xu Xia,Zhou Xuehui
Journal of Ovarian Research , 2013, DOI: 10.1186/1757-2215-6-14
Abstract: Background There is no consensus regarding the management of ovarian cancer patients, who have shown complete clinical response (CCR) to primary therapy and have rising cancer antigen CA-125 levels but have no symptoms of recurrent disease. The present study aims to determine whether follow-up CA-125 levels can be used to identify the need for imaging studies and secondary cytoreductive surgery (CRS). Methods We identified 410 ovarian cancer patients treated at The University of Texas MD Anderson Cancer Center between 1984 and 2011. These patients had shown CCR to primary therapy. Follow-up was conducted based on the surveillance protocol of the MD Anderson Cancer Center. We used the Cox proportional hazards model and log-rank test to assess the associations between the follow-up CA-125 levels and secondary CRS and survival duration. Results The CA-125 level of 1.68 × nadir was defined as the indicator of recurrent disease (p < 0.001). The specificity and sensitivity of this criterion were 82.9% and 85.6%, respectively, and the median lead-time of the CA-125 biochemical progression prior to clinically-defined relapse was 31 days (ranging from 1 to 391 days). The median number of the negative imaging studies for the clinical relapse findings in patients with a CA-125 level of < 1.68 × nadir was 3 (ranging from 0 to 24 times). The increase of CA-125 level at relapse was an independent predictor of overall and progression free survival in patients who had shown CCR to primary therapy (p = 0.04 and 0.02 respectively). The overall and progression free survival durations in patients with a CA-125 level ≤ 1.68 × nadir at relapse (69.4 and 13.8 months) were longer than those with a CA-125 level > 1.68 × nadir at relapse (55.7 and 10.4 months; p = 0.04 and 0.01, respectively). The overall and progression free survival duration of patients with asymptomatic relapse and underwent a secondary CRS was longer than that of patients with symptomatic relapse (p = 0.02 and 0.04 respectively). Conclusions The increase of serum CA-125 levels is an early warning of clinical relapse in ovarian cancer. Using CA-125 levels in guiding the treatment of patients with asymptomatic recurrent ovarian cancer, who have shown CCR to primary therapy, can facilitate optimal secondary CRS and extend the survival duration of the patients.
Solution Behavior and Activity of a Halophilic Esterase under High Salt Concentration
Lang Rao, Xiubo Zhao, Fang Pan, Yin Li, Yanfen Xue, Yanhe Ma, Jian R. Lu
PLOS ONE , 2009, DOI: 10.1371/journal.pone.0006980
Abstract: Background Halophiles are extremophiles that thrive in environments with very high concentrations of salt. Although the salt reliance and physiology of these extremophiles have been widely investigated, the molecular working mechanisms of their enzymes under salty conditions have been little explored. Methodology/Principal Findings A halophilic esterolytic enzyme LipC derived from archeaon Haloarcula marismortui was overexpressed from Escherichia coli BL21. The purified enzyme showed a range of hydrolytic activity towards the substrates of p-nitrophenyl esters with different alkyl chains (n = 2?16), with the highest activity being observed for p-nitrophenyl acetate, consistent with the basic character of an esterase. The optimal esterase activities were found to be at pH 9.5 and [NaCl] = 3.4 M or [KCl] = 3.0 M and at around 45°C. Interestingly, the hydrolysis activity showed a clear reversibility against changes in salt concentration. At the ambient temperature of 22°C, enzyme systems working under the optimal salt concentrations were very stable against time. Increase in temperature increased the activity but reduced its stability. Circular dichroism (CD), dynamic light scattering (DLS) and small angle neutron scattering (SANS) were deployed to determine the physical states of LipC in solution. As the salt concentration increased, DLS revealed substantial increase in aggregate sizes, but CD measurements revealed the maximal retention of the α-helical structure at the salt concentration matching the optimal activity. These observations were supported by SANS analysis that revealed the highest proportion of unimers and dimers around the optimal salt concentration, although the coexistent larger aggregates showed a trend of increasing size with salt concentration, consistent with the DLS data. Conclusions/Significance The solution α-helical structure and activity relation also matched the highest proportion of enzyme unimers and dimers. Given that all the solutions studied were structurally inhomogeneous, it is important for future work to understand how the LipC's solution aggregation affected its activity.
Visible light-induced degradation of organic pollutants using Fe(II) supported on silica gel as an effective catalyst
Chao Zhao,YingPing Huang,YanFen Fang,LiRong Jiang,LiMing Liu,King Tong Lau
Chinese Science Bulletin , 2008, DOI: 10.1007/s11434-007-0524-2
Abstract: Silica gel-supported Fe(II) (SiOFe) was prepared and used for heterogeneous degradation of sulforhodamine B (SRB) and 2,4-dichlorophenol (DCP) under visible irradiation (λ > 420 nm) as an effective catalyst. UV-visible spectra, and infrared Spectrophotometry (IR), fluorescence, total organic carbon (TOC) and electron spin resonance (ESR) measurements were employed to analyze the photoreaction products. The results showed that SRB could be efficiently degraded by SiOFe/H2O2 system under visible irradiation with 100% decolorization and 72.3% TOC removal after 180 min illumination. The results of ESR and fluorescence measurements indicated that the oxidative process was predominated mainly by the hydroxyl radical (·OH) generated in the system.
Catalysis of organic pollutant photodegradation by metal phthalocyanines immobilized on TiO2@SiO2
ShuLian Wang,YanFen Fang,Yong Yang,JunZi Liu,AnPing Deng,XiaoRong Zhao,YingPing Huang
Chinese Science Bulletin , 2011, DOI: 10.1007/s11434-010-4280-3
Abstract: A TiO2@SiO2 hybrid support was prepared by the sol-precipitation method using n-octylamine as a template. The photocatalyst manganese phthalocyanine tetrasulfonic acid (MnPcS) was immobilized on the support to form MnPcS-TiO2@SiO2. X-ray diffraction (XRD) and UV-Visible diffuse reflectance spectra (UV-Vis DRS) were employed to characterize the catalyst. The photocatalytic degradation of rhodamine B (RhB) and the catalytic oxidation of o-phenylenediamine (OPDA) under visible light irradiation were used as probe reactions. The mineralization efficiency and the degradation mechanism were evaluated using chemical oxygen demand (CODCr) assays and electron spin resonance (ESR), respectively. RhB was efficiently degraded by immobilized MnPcS-TiO2@SiO2 under visible light irradiation. Complete decolorization of RhB occurred after 240 min of irradiation and 64.02% CODCr removal occurred after 24 h of irradiation. ESR results indicated that the oxidation process was dominated by the hydroxyl radical (·OH) and superoxide radical (O 2 · ) generated in the system.
Visible light-induced degradation of organic pollutants using Fe(II) supported on silica gel as an effective catalyst
ZHAO Chao,HUANG YingPing,FANG YanFen,JIANG LiRong,LIU LiMing,King Tong Lau,

科学通报(英文版) , 2008,
Abstract: Silica gel-supported Fe(II) (SiOFe) was prepared and used for heterogeneous degradation of sulforhodamine B (SRB) and 2,4-dichlorophenol (DCP) under visible irradiation (λ > 420 nm) as an effective catalyst. UV-visible spectra, and infrared Spectrophotometry (IR), fluorescence, total organic carbon (TOC) and electron spin resonance (ESR) measurements were employed to analyze the photoreaction products. The results showed that SRB could be efficiently degraded by SiOFe/H2O2 system under visible irradiation with 100% decolorization and 72.3% TOC removal after 180 min illumination. The results of ESR and fluorescence measurements indicated that the oxidative process was predominated mainly by the hydroxyl radical (·OH) generated in the system. Supported by the National Natural Science Foundation of China (Grant Nos. 50639070 and 20373074), the Youth Outstanding Foundation of Hubei Province of China (Grant No. 2005ABB030) and the Natural Science Research Plan Project of Education Office of Hubei Province of China (Grant No. 2004Z001)
BRCA1, Hormone, and Tissue-Specific Tumor Suppression
Yanfen Hu
International Journal of Biological Sciences , 2009,
Abstract: Germline mutations of BRCA1 predispose women to breast and ovarian cancers. Elucidating molecular mechanism of tissue- and gender-specific phenomena in BRCA1-related tumors is a key to our understanding of BRCA1 function in tumor suppression. This review summarizes studies in recent years on the link between BRCA1 and estrogen/progesterone signaling pathways, as well as discusses various models underscoring a triangle relationship among BRCA1, estrogen and genome instability.
Empirical Analyses on State-owned Stockholder's Rights and the Performance of China’s Natural Monopoly Industry
Yanfen Qu
International Journal of Business and Management , 2009,
Abstract: The paper analyses the states quo of the China’s natural monopoly industry property right and selects 64 companies in electric power, the coal gas and the water production and supply industry as the sample, to analyze the state-owned stock proportion to the achievements expressed by net assets returns ratio influence. Such conclusions can be drown: First, the state-owned stock proportion and the company achievement present the non-linear correlation dependence; Second, controlling shareholder's state-owned property right nature and performance present remarkable inverse correlation, the relation of state-owned stock proportion and net assets returns ratio present inverse "U" shape. Therefore, in the present stage, the state-owned stock proportion in natural monopoly industry should be reduced. But it is not suitable to withdraw or to privatization completely, that is to say, the state-owned capital should still maintain the controlling force.
A Study on Farmland Circulation Characteristic and Its Influencing Factors Based on a Household Survey in Metropolitan Suburbs
基于农户调查的大城市郊区农地流转特征及影响因素研究

FENG Yanfen,DONG Yuxiang,LIU Yihua,WANG Fang,
冯艳芬
,董玉祥,刘毅华,王 芳

资源科学 , 2010,
Abstract: Reasonable farmland circulation is beneficial to farmland concentration, developing scale operation of agriculture, and improving profits and utilization of land resources. Metropolitan suburbs with superior geographic location and economic radiation infl
Targeting Cadherin-17 Inactivates Ras/Raf/MEK/ERK Signaling and Inhibits Cell Proliferation in Gastric Cancer
Zhaohu Lin, Chao Zhang, Meifang Zhang, Danqing Xu, Yanfen Fang, Zheng Zhou, Xiaolong Chen, Ning Qin, Xiongwen Zhang
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0085296
Abstract: Cadherin-17 (CDH17), one member of 7D-cadherin superfamily, was overexpressed in gastric cancer (GC) and was associated with poor survival, tumor recurrence, metastasis, and advanced tumor stage. So far the cellular function and signaling mechanism of CDH17 in GC remains unclear. In this study, we showed that over 66% of GC cell lines (20/30) were CDH17 positive. Tissue microarray (TMA) assay showed that 73.6% Chinese GC tissues (159/216) were CDH17 positive, while 37% respective adjacent normal tissues were CDH17 positive. Knockdown of CDH17 inhibited cell proliferation, migration, adhesion and colony formation, and also induced a cell cycle arrest and apoptosis in AGS human GC cells. On the other side, overexpression of CDH17 facilitated MGC-803 GC tumor growth in nude mice. Antibody array and Western blotting assay demonstrated that knockdown of CDH17 in AGS cells down-regulated integrin β series proteins, further inactivated the Ras/Raf/MEK/ERK pathway and led to p53 and p21 accumulation, which resulted in proliferation inhibition, cell-cycle arrest and apoptosis induction. Collectively, our data firstly demonstrate the capacity of CDH17 to regulate the activity of Ras/Raf/MEK/ERK pathway for cell proliferation in GC, and suggest that CDH17 can serve as an attractive therapeutic target for future research.
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