期刊文献+
共找到3,710篇文章
< 1 2 186 >
每页显示 20 50 100
Effectiveness of fecal DNA syndecan-2 methylation testing for detection of colorectal cancer in a high-risk Chinese population
1
作者 Wen-Feng Luo Yu-Ting Jiao +9 位作者 Xiao-Ling Lin Ying Zhao Sheng-Bo Wang Jian Shen Jie Deng Yu-Feng Ye Ze-Ping Han Fang-Mei Xie Jin-Hua He Yu Wan 《World Journal of Gastrointestinal Oncology》 SCIE 2024年第4期1361-1373,共13页
BACKGROUND Colorectal cancer(CRC)is among the most prevalent and life-threatening malignancies worldwide.Syndecan-2 methylation(mSDC2)testing has emerged as a widely used biomarker for early detection of CRC in stool ... BACKGROUND Colorectal cancer(CRC)is among the most prevalent and life-threatening malignancies worldwide.Syndecan-2 methylation(mSDC2)testing has emerged as a widely used biomarker for early detection of CRC in stool and serum samples.Cancer(CRC)is among the most prevalent and life-threatening malignancies worldwide.mSDC2 testing has emerged as a widely used biomarker for early detection of CRC in stool and serum samples.AIM To validate the effectiveness of fecal DNA mSDC2 testing in the detection of CRC among a high-risk Chinese population to provide evidence-based data for the development of diagnostic and/or screening guidelines for CRC in China.METHODS A high-risk Chinese cohort consisting of 1130 individuals aged 40-79 years was selected for evaluation via fecal mSDC2 testing.Sensitivity and specificity for CRC,advanced adenoma(AA)and advanced colorectal neoplasia(ACN)were determined.High-risk factors for the incidence of colorectal lesions were determined and a logistic regression model was constructed to reflect the efficacy of the test.RESULTS A total of 1035 high-risk individuals were included in this study according to established criteria.Among them,16 suffered from CRC(1.55%),65 from AA(6.28%)and 189 from non-AAs(18.26%);150 patients were diagnosed with polyps(14.49%).Diagnoses were established based upon colonoscopic and pathological examinations.Sensitivities of the mSDC2 test for CRC and AA were 87.50%and 40.00%,respectively;specificities were 95.61%for other groups.Positive predictive values of the mSDC2 test for CRC,AA and ACN were 16.09%,29.89%and 45.98%,respectively;the negative predictive value for CRC was 99.79%.After adjusting for other high-risk covariates,mSDC2 test positivity was found to be a significant risk factor for the occurrence of ACN(P<0.001).CONCLUSION Our findings confirmed that offering fecal mSDC2 testing and colonoscopy in combination for CRC screening is effective for earlier detection of malignant colorectal lesions in a high-risk Chinese population. 展开更多
关键词 Colorectal cancer Syndecan-2 DNA methylation Chinese population
下载PDF
Tuning the product selectivity of dimethyl oxalate hydrogenation over WO_(x) modified Cu/SiO_(2) catalysts
2
作者 Zheng Li Zhuo Ma +9 位作者 Yihui Li Ziang Zhao Yuan Tan Ziyin Liu Xingkun Chen Nian Lei Huigang Wang Wei Lu Hejun Zhu Yunjie Ding 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第10期128-138,I0004,共12页
Product selectivity and reaction pathway are highly dependent on surface structure of heterogeneous catalysts.For vapor-phase hydrogenation of dimethyl oxalate(DMO),"EG route"(DMO→methyl glycolate(MG)ethyle... Product selectivity and reaction pathway are highly dependent on surface structure of heterogeneous catalysts.For vapor-phase hydrogenation of dimethyl oxalate(DMO),"EG route"(DMO→methyl glycolate(MG)ethylene glycol(EG)→ethanol(ET))and"MA route"(DMO→MG→methyl acetate(MA))were proposed over traditional Cu based catalysts and Mo-based or Fe-based catalysts,respectively.Herein,tunable yield of ET(93.7%)and MA(72.1%)were obtained through different reaction routes over WO_(x) modified Cu/SiO_(2) catalysts,and the corresponding reaction route was further proved by kinetic study and in-situ DRIFTS technology.Mechanistic studies demonstrated that H_(2) activation ability,acid density and Cu-WO_(x) interaction on the catalysts were tuned by regulating the surface W density,which resulted in the different reaction pathway and product selectivity.What's more,high yield of MA produced from DMO hydrogenation was firstly reported with the H_(2) pressure as low as 0.5 MPa. 展开更多
关键词 ETHANOL Dimethyl oxalate Selective hydrogenation methyl acetate WCu/SiO_(2)catalyst
下载PDF
Salsolinol as an RNA m~6A methylation inducer mediates dopaminergic neuronal death by regulating YAP1 and autophagy
3
作者 Jianan Wang Yuanyuan Ran +5 位作者 Zihan Li Tianyuan Zhao Fangfang Zhang Juan Wang Zongjian Liu Xuechai Chen 《Neural Regeneration Research》 SCIE CAS 2025年第3期887-899,共13页
Salsolinol(1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline,Sal)is a catechol isoquinoline that causes neurotoxicity and shares structural similarity with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine,an environme... Salsolinol(1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline,Sal)is a catechol isoquinoline that causes neurotoxicity and shares structural similarity with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine,an environmental toxin that causes Parkinson's disease.However,the mechanism by which Sal mediates dopaminergic neuronal death remains unclear.In this study,we found that Sal significantly enhanced the global level of N~6-methyladenosine(m~6A)RNA methylation in PC12 cells,mainly by inducing the downregulation of the expression of m~6A demethylases fat mass and obesity-associated protein(FTO)and alk B homolog 5(ALKBH5).RNA sequencing analysis showed that Sal downregulated the Hippo signaling pathway.The m~6A reader YTH domain-containing family protein 2(YTHDF2)promoted the degradation of m~6A-containing Yes-associated protein 1(YAP1)mRNA,which is a downstream key effector in the Hippo signaling pathway.Additionally,downregulation of YAP1 promoted autophagy,indicating that the mutual regulation between YAP1 and autophagy can lead to neurotoxicity.These findings reveal the role of Sal on m~6A RNA methylation and suggest that Sal may act as an RNA methylation inducer mediating dopaminergic neuronal death through YAP1 and autophagy.Our results provide greater insights into the neurotoxic effects of catechol isoquinolines compared with other studies and may be a reference for assessing the involvement of RNA methylation in the pathogenesis of Parkinson's disease. 展开更多
关键词 ALKBH5 AUTOPHAGY FTO Hippo pathway m~6A Parkinson's disease RNA methylation SALSOLINOL YAP1 YTHDF2
下载PDF
三萜类化合物Bardoxolone methyl对急性呼吸窘迫综合征大鼠氧化应激信号通路Nrf2-ARE/HO-1的影响 被引量:1
4
作者 谭国良 刘玉琪 《中国急救医学》 CAS CSCD 北大核心 2019年第3期269-273,共5页
目的观察三萜类化合物Bardoxolone methyl(BARD)对急性呼吸窘迫综合征(ARDS)大鼠氧化应激信号通路核转录因子相关因子2(Nrf2-ARE)/血红素氧合酶-1(HO-1)的影响。方法100只大鼠按随机数字法分为药物BARD组及生理盐水组,喂养一周后两组按... 目的观察三萜类化合物Bardoxolone methyl(BARD)对急性呼吸窘迫综合征(ARDS)大鼠氧化应激信号通路核转录因子相关因子2(Nrf2-ARE)/血红素氧合酶-1(HO-1)的影响。方法100只大鼠按随机数字法分为药物BARD组及生理盐水组,喂养一周后两组按是否建立ARDS模型再各分为两亚组,产生四组:ARDS模型+BARD干预组(A1组),ARDS模型+生理盐水组(A2组),正常+BARD干预组(B1组),正常+生理盐水组(B2组)。各组大鼠再喂养72h后处死留取肺组织及血液标本。病理观察肺组织结构变化。免疫组织化学检测肺组织Nrf2、HO-1蛋白表达情况。反转录-多聚酶链反应(RT-PCR)检测肺组织Nrf2 mRNA、HO-1 mRNA表达情况。结果肺组织病理结构变化:A2组肺组织损伤程度最重,病理评分最高。其次A1组,B1及B2组结构大致正常。Nrf2、HO-1蛋白表达情况:A1组(3.78±0.37,2.86±0.16)及B1组(3.01±0.34,2.47±0.19)高于A2(1.82±0.31,2.01±0.21)及B2组(0.92±0.13,1.41±0.17),A1组高于B1组,A2组高于B2组(P均<0.05)。Nrf2mRNA、HO-1mRNA表达情况:A1组(2.16±0.17,1.45±0.12)最为明显,B1组(1.79±0.14,1.18±0.05)高于B2组(0.42±0.06,0.68±0.11),A2组(1.18±0.19,1.01±0.07)高于B2组(0.42±0.06,0.68±0.11,P均<0.05)。结论三萜类化合物Bardoxolone methyl能够明显上调肺组织Nrf2-ARE/HO-1信号通路相关蛋白的表达,从而发挥抗氧化应激作用,减轻ARDS时肺组织的损伤。 展开更多
关键词 三萜类化合物 Bardoxolone methyl 急性呼吸窘迫综合征(ARDS) 血红素氧合酶-1(HO-1) 核转录因子相关因子2(Nrf2-ARE)
下载PDF
新型长效植物调节剂2-O-β-L-glucopyranoside-4-O-methyl phloracetophenone的全合成
5
作者 陈靖 李晓东 +3 位作者 孙铁民 张蕾 吴秀丽 王金辉 《天然产物研究与开发》 CAS CSCD 北大核心 2013年第11期1469-1473,共5页
以β-L-(-)葡萄糖、无水醋酐及吡啶为原料,通过五步反应进行全合成,制备一种新型植物生长调节剂;β-D-葡萄糖水解酶催化下进行水解反应,研究其水解曲线。全合成产物经1H NMR鉴定为2-O-β-L-glucopyranoside-4-O-methyl phloracetophenon... 以β-L-(-)葡萄糖、无水醋酐及吡啶为原料,通过五步反应进行全合成,制备一种新型植物生长调节剂;β-D-葡萄糖水解酶催化下进行水解反应,研究其水解曲线。全合成产物经1H NMR鉴定为2-O-β-L-glucopyranoside-4-O-methyl phloracetophenone(1),总得率17.4%;水解实验表明domesticoside(2)可被β-D-葡萄糖水解酶水解为苷元,而化合物(1)不被水解。本法可作为一种新型长效生长调节剂的制备方法,也为体内快速被β-D-葡萄糖水解酶水解失活药物的结构修饰提供了新的思路。 展开更多
关键词 2-O-β-L-glueopyranoside-4-O-methylphloraeetophenone β-L-(-)葡萄糖 水解 调节剂
下载PDF
FAM 19A 4、PAX 1及miRNA124-2基因启动子区甲基化在宫颈病变早期诊断中的价值
6
作者 李雅 刘慧 +2 位作者 任静静 李肖甫 智艳芳 《中国癌症杂志》 CAS CSCD 北大核心 2024年第8期734-744,共11页
背景与目的:目前有关宫颈病变的DNA甲基化研究较多,但DNA甲基化作为宫颈病变的诊断及分流指标在临床实践中的报道较少。本研究拟探讨FAM19A4、PAX1及miRNA124-2基因启动子区甲基化在宫颈病变进展中早期诊断的价值。方法:收集2020年3月—... 背景与目的:目前有关宫颈病变的DNA甲基化研究较多,但DNA甲基化作为宫颈病变的诊断及分流指标在临床实践中的报道较少。本研究拟探讨FAM19A4、PAX1及miRNA124-2基因启动子区甲基化在宫颈病变进展中早期诊断的价值。方法:收集2020年3月—2022年3月在郑州大学第三附属医院同时行宫颈液基细胞学(thinprep cytologic test,TCT)和HPV检测的患者的宫颈细胞学标本共129例,采用甲基化特异性PCR(methylation-specific PCR,MSP)检测不同宫颈病变中FAM19A4、PAX1及miRNA124-2基因启动子区甲基化改变情况,采用受试者工作特征(receiver operating characteristic,ROC)曲线评估3个基因甲基化改变对宫颈病变的诊断价值。本研究经郑州大学第三附属医院伦理委员会批准(伦理审批编号:2023-135-01)。结果:根据病理学检查结果分为4组:未见上皮内病变或恶性细胞(no intraepithelial lesions or malignant lesions,NILM)组(42例)、低度鳞状上皮内病变(low grade squamous intraepithelial lesion,LSIL)组(28例)、高度鳞状上皮内病变(high grade squamous intraepithelial lesion,HSIL)组(36例)和鳞癌(squamous cervical cancer,SCC)组(23例)。随宫颈病变级别的增加,FAM19A4、PAX1及miRNA124-2基因甲基化检出率逐步增高,差异有统计学意义(P均<0.05)。在HSIL组FAM19A4、PAX1、miRNA124-2甲基化检出率分别为81.2%、80.5%和71.8%,在SCC组3种基因甲基化检出率均高达100.0%;细胞学诊断宫颈癌的ROC曲线下面积(area under curve,AUC)为0.731,诊断灵敏度和特异度分别为65.9%和80.4%;FAM19A4、PAX1及miRNA124-2基因单独诊断HSIL+(HSIL和SCC)时,PAX1甲基化诊断HSIL+的效能最高,AUC为0.925,灵敏度为92.8%,特异度为87.3%;两两联合诊断时,FAM19A4与PAX1联合诊断HSIL+的AUC为0.930,灵敏度为95.7%,特异度为87.1%;FAM19A4与miRNA124-2联合诊断HSIL+,AUC为0.895,灵敏度为97.6%,特异度为85.7%;PAX1联合miRNA124-2诊断HSIL+,AUC为0.928,灵敏度为95.7%,特异度为89.1%;PAX1、FAM19A4及miRNA124-2基因甲基化联合诊断HSIL+,AUC为0.928,灵敏度为100.0%,特异度为81.8%。结论:FAM19A4、PAX1及miRNA124-2基因启动子区甲基化诊断宫颈病变具有较高的灵敏度和特异度,有潜力成为宫颈病变早期诊断的新指标。 展开更多
关键词 FAM19A4 PAX1 miRNA124-2 甲基化 宫颈病变
下载PDF
TET2重塑CXCR4 DNA甲基化对急性心肌梗死小鼠心肌组织自噬、炎症反应及凋亡的影响
7
作者 毛山 周明 +2 位作者 段班燕 曹政 李军 《中西医结合心脑血管病杂志》 2024年第9期1579-1584,共6页
目的:探究急性心肌梗死(AMI)过程中内皮细胞tet甲基胞嘧啶双加氧酶2(TET2)对趋化因子受体4(CXCR4)DNA甲基化的影响以及对AMI小鼠心肌组织自噬、炎症反应及组织细胞凋亡的影响机制,为临床探究AMI发展的分子机制提供理论依据。方法:8周龄... 目的:探究急性心肌梗死(AMI)过程中内皮细胞tet甲基胞嘧啶双加氧酶2(TET2)对趋化因子受体4(CXCR4)DNA甲基化的影响以及对AMI小鼠心肌组织自噬、炎症反应及组织细胞凋亡的影响机制,为临床探究AMI发展的分子机制提供理论依据。方法:8周龄雄性C57/BL6小鼠50只,制备AMI模型,尾部注射TET2、CXCR4过表达质粒;蛋白免疫印迹(Western Blot)法检测心肌组织TET2、CXCR4、微管相关蛋白3(LC3)、P62、B细胞淋巴瘤/白血病-2基因(Bcl-2)关联X蛋白(Bax)、半胱氨酸蛋白酶3(Caspase-3)、Bcl-2表达;甲基化检测CXCR4 DNA甲基化水平;酶联免疫吸附法(ELISA)检测心肌组织内炎性因子白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)水平;原位末端转移酶标记技术(TUNEL)检测各组心肌组织细胞凋亡指数。结果:与假手术组比较,模型组心肌组织内TET2、CXCR4均表达上调,TET2、CXCR4均在心肌组织内过表达,TET2过表达促进CXCR4表达,差异有统计学意义(P<0.05);与模型组比较,TET2 mimic组CXCR4启动子区域DNA甲基化程度降低,CXCR4蛋白表达升高,差异有统计学意义(P<0.05);与假手术组比较,模型组小鼠心肌组织自噬蛋白LC3、抑制细胞凋亡蛋白Bcl-2表达下调,炎性因子IL-6、TNF-α、IL-1β水平、自噬蛋白P62、促细胞凋亡蛋白Bax、cleaved Caspase-3表达上调,差异有统计学意义(P<0.05);TET2、CXCR4过表达进一步下调LC3、Bcl-2蛋白表达,上调炎性因子IL-6、TNF-α、IL-1β水平,P62、Bax、cleaved Caspase-3蛋白表达;TET2、CXCR4二者联合体现出最低LC3、Bcl-2蛋白表达,最高炎性因子IL-6、TNF-α、IL-1β水平以及P62、Bax、cleaved Caspase-3蛋白表达,差异有统计学意义(P<0.05)。结论:AMI发展中,TET2通过降低CXCR4 DNA甲基化,促进CXCR4基因表达,进而抑制AMI小鼠心肌组织自噬,上调炎症反应及细胞凋亡程度,促进疾病发展。 展开更多
关键词 急性心肌梗死 tet甲基胞嘧啶双加氧酶2 趋化因子受体4 DNA甲基化 自噬 炎症反应 凋亡
下载PDF
Hypermethylated SFRP2 gene in fecal DNA is a high potential biomarker for colorectal cancer noninvasive screening 被引量:25
8
作者 Dao-RongWang Dong Tang 《World Journal of Gastroenterology》 SCIE CAS CSCD 2008年第4期524-531,共8页
AIM: To investigate the feasibility of detecting hypermethylated secreted frizzled-related protein 2 (SFRP2) gene in fecal DNA as a non-invasive screening tool for colorectal cancer (CRC). METHODS: Fluorescence-based ... AIM: To investigate the feasibility of detecting hypermethylated secreted frizzled-related protein 2 (SFRP2) gene in fecal DNA as a non-invasive screening tool for colorectal cancer (CRC). METHODS: Fluorescence-based real-time PCR assay (MethyLight) was performed to analyze SFRP2 gene promoter methylation status in a blinded fashion in tumor tissues and in stool samples taken from 69 CRC patients preoperatively and at the 9th postoperative day,34 patients with adenoma ≥ 1 cm,26 with hyperplastic polyp,and 30 endoscopically normal subjects. Simultaneously the relationship between hypermethylation of SFRP2 gene and clinicopathological features was analyzed. RESULTS: SFRP2 gene was hypermethylated in 91.3% (63/69) CRC,79.4% (27/34) and 53.8% (14/26) adenoma and hyperplastic polyp tissues,and in 87.0% (60/69),61.8% (21/34) and 42.3% (11/26) of corresponding fecal samples,respectively. In contrast,no methylated SFRP2 gene was detected in mucosal tissues of normal controls,while two cases of matched fecal samples from normal controls were detected with hypermethylated SFRP2. A significant decrease (P < 0.001) in the rate of hypermethylated SFRP2 gene was detected in the postoperative (8.7%,6/69) fecal samples as compared with the preoperative fecal samples (87%,60/69) of CRC patients. Moreover,no significant associations were observed between SFRP2 hypermethylation and clinicopathological features including sex,age,tumor stage,site,lymph node status and histological grade,etc. CONCLUSION: Hypermethylation of SFRP2 gene in fecal DNA is a novel molecular biomarker of CRC and carries a high potential for the remote detection of CRC and premalignant lesions as noninvasive screening method. 展开更多
关键词 Colorectal cancer Secreted frizzled-relatedprotein 2 FECES methylation SCREENING
下载PDF
Role of H3K27 methylation in the regulation of IncRNA expression 被引量:22
9
作者 Susan C Wu 《Cell Research》 SCIE CAS CSCD 2010年第10期1109-1116,共8页
Once thought to be transcriptional noise, large non-coding RNAs (IncRNAs) have recently been demonstrated to be functional molecules. The cell-type-specific expression patterns of lncRNAs suggest that their transcri... Once thought to be transcriptional noise, large non-coding RNAs (IncRNAs) have recently been demonstrated to be functional molecules. The cell-type-specific expression patterns of lncRNAs suggest that their transcription may be regulated epigenetically. Using a custom-designed microarray, here we examine the expression profile of IncRNAs in embryonic stem (ES) cells, lineage-restricted neuronal progenitor cells, and terminally differentiated fibroblasts. In addition, we also analyze the relationship between their expression and their promoter H3K4 and H3K27 methyla- tion patterns. We find that numerous lncRNAs in these cell types undergo changes in the levels of expression and promoter H3K4me3 and H3K27me3. Interestingly, lncRNAs that are expressed at lower levels in ES cells exhibit higher levels of H3K27me3 at their promoters. Consistent with this result, knockdown of the H3K27me3 methyltransferase Ezh2 results in derepression of these IncRNAs in ES cells. Thus, our results establish a role for Ezh2-mediated H3K27 methylation in lncRNA silencing in ES cells and reveal that lncRNAs are subject to epigenetic regulation in a similar manner to that of the protein-coding genes. 展开更多
关键词 IncRNA histone methylation Polycomb repressive complex 2
下载PDF
Synthesis of Methyl Glycolate by Hydrogenation of Dimethyl Oxalate over Cu-Ag/SiO_2 Catalyst 被引量:26
10
作者 Baowei Wang Qian Xu Hua Song Genhui Xu 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2007年第1期78-80,共3页
Methyl glycolate is a good solvent and can be used as feedstock for the synthesis of some important organic chemicals. Catalytic hydrogenation of dimethyl oxalate (DMO) over copper-silver catalyst supported on silic... Methyl glycolate is a good solvent and can be used as feedstock for the synthesis of some important organic chemicals. Catalytic hydrogenation of dimethyl oxalate (DMO) over copper-silver catalyst supported on silica was studied. The Cu-Ag/SiO2 catalyst supported on silica sol was prepared by homogeneous deposition-precipitation of the mixture of aqueous euprammonia complex and silica sol. The proper active temperature of Cu-Ag/SiO2 catalyst for hydrogenation of DMO was 523-623 K. The most preferable reaction conditions for methyl glycolate (MG) were optimized: temperature at 468-478 K, 40-60 mesh catalyst diameter, H2/DMO ratio 40, and 1.0 h^-1 of LHSV. 展开更多
关键词 dimethyl oxalate methyl glycolate ethylene glycol HYDROGENATION Cu-Ag/SiO2 catalyst
下载PDF
Photodegradation of methyl orange by BiOI-sensitized TiO_2 被引量:10
11
作者 Li Huiquan Cui Yumin +2 位作者 Hong Wenshan Hua Lin Tao Dongliang 《Rare Metals》 SCIE EI CAS CSCD 2012年第6期604-610,共7页
BiOI-sensitized titanium dioxide (TiO2) photocatalysts were prepared by a deposition method at room temperature and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller su... BiOI-sensitized titanium dioxide (TiO2) photocatalysts were prepared by a deposition method at room temperature and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller surface area measurements. The photocatalytic activities of the catalysts were evaluated for the degradation of methyl orange (MO) solution under UV and visible light irradiation. The effects of catalyst amount, initial pH value, initial concentration of MO, as well as KI amount were investigated. The repeatability of photocatalytic activity of the 1.7% BiOI/TiO2 catalyst was also tested. It is shown that BiOI sensitization enhances the photocatalytic activities of TiO2. With BiOI content increasing, the photocatalytic activities of BiOI/TiO2 under UV and visible light irradiation first increase, reaching a maximum around BiOI content of 1.7%, and then decrease with further increasing BiOI content. The 1.7% BiOI/TiO2 catalyst obviously exhibits much higher visible light photocatalytic activity than P25, and its UV light photocatalytic activity is slightly higher than that of P25. Under the conditions of a catalytic dose of 1.5 g.L-1, initial pH of 3.0, initial MO concentration of 20 mg.L-1, UV power of 300 W, and air flow rate of 0.8 L.min-1, complete degradatio is achieved within 60 min. The repeatability of photocatalytic activity of the 1.7% BiOI/TiO2 catalyst is highly reliable. 展开更多
关键词 sensitized TiO2 BiOI photocatalytic degradation methyl orange
下载PDF
In_2O_3-modified Cu/SiO_2 as an active and stable catalyst for the hydrogenation of methyl acetate to ethanol 被引量:11
12
作者 Yu Zhang Chenliang Ye +2 位作者 Cuili Guo Changna Gan Xinmeng Tong 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2018年第1期99-108,共10页
A series of indium oxide‐modified Cu/SiO2catalysts were synthesized and used to produce ethanol via methyl acetate hydrogenation.In‐Cu/SiO2catalyst containing1.0wt%In2O3exhibited the best catalytic activity and stab... A series of indium oxide‐modified Cu/SiO2catalysts were synthesized and used to produce ethanol via methyl acetate hydrogenation.In‐Cu/SiO2catalyst containing1.0wt%In2O3exhibited the best catalytic activity and stability.The physicochemical properties of the synthesized catalysts were investigated using several characterization methods and the results showed that introducing suitable indium to Cu/SiO2increased the copper dispersion,diminished the copper crystallite size,and enriched the surface Cu+concentration.Furthermore,the Cu/SiO2catalyst gradually deactivated during the stability test,which was mainly attributed to copper sintering and the valence change in surface copper species.In contrast,indium addition can inhibit the thermal transmigration and accumulation of copper nanoparticles to stabilize the catalyst.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved. 展开更多
关键词 methyl acetate HYDROGENATION INDIUM Cu/SiO2 catalyst ETHANOL
下载PDF
Methylation of RAR-β2, RASSF1A, and CDKN2A Genes Induced by Nickel Subsulfide and Nickel-carcinogenesis in Rats 被引量:5
13
作者 ZHANG Jun ZHANG Jing +6 位作者 LI MengJie Wu YouJun FAN YingYing ZHOU Yang TAN LiLi SHAO ZhiHua SHI HongJun 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2011年第2期163-171,共9页
Objective To investigate the expression variation of RAR‐β2, RASSF1A, and CDKN2A gene in the process of nickel‐induced carcinogenesis. Methods Nickel subsulfide (Ni 3 S 2 ) at dose of 10 mg was given to Wistar ra... Objective To investigate the expression variation of RAR‐β2, RASSF1A, and CDKN2A gene in the process of nickel‐induced carcinogenesis. Methods Nickel subsulfide (Ni 3 S 2 ) at dose of 10 mg was given to Wistar rats by intramuscular injection. The mRNA expression of the three genes in induced tumors and their lung metastasis were examined by Real‐time PCR. The methylation status of the 5’ region of these genes were detected by Quantitative Real‐time methylation specific PCR. Results The mRNA expressions of the three genes both in muscle and lung tumor were decreased distinctly in comparison with normal tissue. But hypermethylation was found only in muscle tumor. Conclusion These findings suggest that loss of function or decrease of RAR‐β2, RASSF1A, and CDKN2A, as well as the hypermethylation of 5’ region of these genes, are related with nickel exposure. 展开更多
关键词 NICKEL DNA methylation RAR‐β2 RASSF1A CDKN2A Quantitative Real‐time methylation Specific PCR
下载PDF
MTHFR C677T polymorphisms are associated with aberrant methylation of the IGF-2 gene in transitional cell carcinoma of the bladder 被引量:3
14
作者 Huan Cheng Zhonglei Deng +2 位作者 Zengjun Wang Wei Zhang Jiantang Su 《The Journal of Biomedical Research》 CAS 2012年第2期77-83,共7页
The purpose of this study was to determine the relationship between methylation status of the insulin-like growth factor 2 (IGF-2) gene and methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphisms in b... The purpose of this study was to determine the relationship between methylation status of the insulin-like growth factor 2 (IGF-2) gene and methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphisms in bladder transitional cell carcinoma tissues in a Chinese population. The polymorphisms of the folate metabolism enzyme gene MTHFR were studied by restrictive fragment length polymorphism (RFLP), PCR-based methods of DNA methylation analysis were used to detect the CpG island methylation status of the IGF-2 gene. The association between the methylation status of the IGF-2 gene and clinical characteristics, as well as MTHFR C677T polymorphisms, was analyzed. Aberrant hypomethylation of the IGF-2 gene was found in 68.3% bladder cancer tissues and 12.4% normal bladder tissues, respectively, while hypomethylation was not detected in almost all normal bladder tissues. The hypomethylation rate of the IGF-2 gene in cancer tissues was significantly higher in patients with lymph node metastasis than in those without lymph node metastasis (46.3% vs 17.2%, P = 0.018). No association was found between aberrant DNA methylation and selected factors including sex, age, tobacco smoking, alcohol consumption and green tea consumption. After adjusting for potential confounding variables the variant allele of MTHFR C677T was found to be associated with hypomethylation of the IGF-2 gene. Compared with wildtype CC, the odds ratio was 4.33 (95% CI=1.06-10.59) for CT and 4,95 (95% CI=1.18-12.74) for TT. MTHFR 677 CC and CT genotypes might be one of the reasons that cause abnormal hypomethylation of the IGF-2 gene, and the aberrant CpG island hypomethylation of the IGF-2 gene may contribute to the genesis and progression of bladder transitional cell carcinoma. 展开更多
关键词 methylenetetrahydrofolate reductase folate epidemiology methylATION bladder transitional cell carcinoma insulin-like growth factor 2 (IGF-2
下载PDF
Methylation of 2-Methylnaphthalene with Methanol over NH_4 F and Pt Modified HZSM-5 Catalysts 被引量:7
15
作者 赵亮 郭新闻 +2 位作者 刘民 王祥生 宋春山 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2010年第5期742-749,共8页
Shape-selective methylation of 2-methylnaphthalene (2-MN) was carried out over NH 4 F and Pt modified HZSM-5 (SiO 2 /Al 2 O 3 = 83) catalysts in a fixed-bed down-flow reactor using methanol as methylating agent and 1,... Shape-selective methylation of 2-methylnaphthalene (2-MN) was carried out over NH 4 F and Pt modified HZSM-5 (SiO 2 /Al 2 O 3 = 83) catalysts in a fixed-bed down-flow reactor using methanol as methylating agent and 1,3,5-trimethylbenzene (1,3,5-TMB) as a solvent. Pt promoted HZSM-5 catalysts showed low concentration of coke-like polycondensed aromatics, NH 4 F modification decreased non-shape-selective acid sites. After Pt and NH 4 F co-modification, both conversion of 2-MN and selectivity to 2,6-DMN were improved. 6%NH 4 F/0.5%Pt/HZSM-5 catalyst exhibited 13.8% of 2-MN conversion with 6.2% of 2,6-DMN yield after 7 h time on stream (TOS), and 2,6-/2,7-DMN ratio of 1.7 after 10 h of TOS. 展开更多
关键词 2-methylNAPHTHALENE methylATION HZSM-5 2 6-dimethylnaphthalene NH 4 F/Pt/HZSM-5
下载PDF
Mechanisms of Enhancement of Photocatalytic Properties and Activity of Nd^(3+)-Doped TiO_2 for Methyl Orange Degradation 被引量:6
16
作者 侯梅芳 李芳柏 +3 位作者 李瑞丰 万洪富 周国逸 谢克昌 《Journal of Rare Earths》 SCIE EI CAS CSCD 2004年第4期542-546,共5页
Nd^(3+)-doped TiO_2 powders were prepared by the sol-gel method. Their crystal pattern and parameter, the specific surface area, the surface chemical state of Ti and the ratio of O/Ti were characterized. The results s... Nd^(3+)-doped TiO_2 powders were prepared by the sol-gel method. Their crystal pattern and parameter, the specific surface area, the surface chemical state of Ti and the ratio of O/Ti were characterized. The results show that Nd impurity hinders the crystal transformation, and decreases the relative intensity of (101) peak. The crystallite sizes of Nd^(3+)-doped TiO_2 powders decrease while their specific surface area increase owing to the Nd^(3+) doping. The XPS measurement shows that the content of Ti(Ⅲ) and ratio of O/Ti on their surfaces increase significantly with the increase of Nd^(3+) dosage. The adsorption and photodegradation experiments show that the optimum molar content of Nd^(3+) is 1.2%. 展开更多
关键词 catalytic chemistry PHOTOCATALYSIS TiO_2 neodymium methyl orange rare earths
下载PDF
Liver insulin-like growth factor 2 methylation in hepatitis C virus cirrhosis and further occurrence of hepatocellular carcinoma 被引量:6
17
作者 Philippe Couvert Alain Carrié +8 位作者 Jacques Pariès Jenny Vaysse Audrey Miroglio Antoine Kerjean Pierre Nahon Jamel Chelly Jean-Claude Trinchet Michel Beaugrand Nathalie Ganne-Carrié 《World Journal of Gastroenterology》 SCIE CAS CSCD 2008年第35期5419-5427,共9页
AIM: To assess the predictive value of the insulinlike growth factor 2 (Igf2) methylation profile for the occurrence of Hepatocellular Carcinoma (HCC) in hepatitis C (HCV) cirrhosis. METHODS: Patients with: (1) biopsy... AIM: To assess the predictive value of the insulinlike growth factor 2 (Igf2) methylation profile for the occurrence of Hepatocellular Carcinoma (HCC) in hepatitis C (HCV) cirrhosis. METHODS: Patients with: (1) biopsy-proven compensated HCV cirrhosis; (2) available baseline frozen liver sample; (3) absence of detectable HCC; (4) regular screening for HCC; (5) informed consent for genetic analysis were studied. After DNA extraction from liver samples and bisulfite treatment, unbiased PCR and DHPLC analysis were performed for methylation analysis at the Igf2 locus. The predictive value of the Igf2 methylation profile for HCC wasassessed by Kaplan-Meier and Cox methods. RESULTS: Among 94 included patients, 20 developed an HCC during follow-up (6.9 ± 3.2 years). The methylation profile was hypomethylated, intermediate and hypermethylated in 13, 64 and 17 cases, respectively. In univariate analysis, two baseline parameters were associated with the occurrence of HCC: age (P = 0.01) and prothrombin (P = 0.04). The test of linear tendency between the three ordered levels of Igf2 methylation and probability of HCC occurrence was significant (Log Rank, P = 0.043; Breslow, P = 0.037; Tarone-Ware, P = 0.039). CONCLUSION: These results suggest that hypomethylation at the Igf2 locus in the liver could be predictive for HCC occurrence in HCV cirrhosis. 展开更多
关键词 Liver cancer CIRRHOSIS Insulin-growth factor 2 DNA methylation
下载PDF
Solid-phase synthesis of Cu2MoS4 nanoparticles for degradation of methyl blue under a halogen-tungsten lamp 被引量:4
18
作者 Shi-na Li Rui-xin Ma Cheng-yan Wang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2018年第3期310-314,共5页
The Cu_2MoS_4 nanoparticles were prepared using a relatively simple and convenient solid-phase process, which was applied for the first time. The crystalline structure, morphology, and optical properties of Cu_2MoS_4 ... The Cu_2MoS_4 nanoparticles were prepared using a relatively simple and convenient solid-phase process, which was applied for the first time. The crystalline structure, morphology, and optical properties of Cu_2MoS_4 nanoparticles were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, and UV-vis spectrophotometry. Cu_2MoS_4 nanoparticles having a band gap of 1.66 eV exhibits good photocatalytic activity in the degradation of methylene blue, which indicates that this simple process may be critical to facilitate the cheap production of photocatalysts. 展开更多
关键词 Cu2MoS4 NANOPARTICLES SOLID-PHASE synthesis DEGRADATION PHOTOCATALYST methyl blue
下载PDF
Synthesis of Comblike Poly(methyl methacrylate) by Atom Transfer Radical Polymerization with Poly(ethyl 2-bromoacrylate) as Macroinitiator 被引量:2
19
作者 YanSHI ZhiFengFU +1 位作者 YuDongZHANG ShuKeJIAO 《Chinese Chemical Letters》 SCIE CAS CSCD 2003年第12期1289-1292,共4页
Comblike poly(methyl methacrylate) was synthesized by atom transfer radical polymerization of methyl methacrylate with poly(ethyl 2-bromoacrylate) as a macroinitiator, which was prepared by conventional free radical p... Comblike poly(methyl methacrylate) was synthesized by atom transfer radical polymerization of methyl methacrylate with poly(ethyl 2-bromoacrylate) as a macroinitiator, which was prepared by conventional free radical polymerization of ethyl 2-bromoacrylate. The obtained comblike polymers were characterized by GPC and 1H NMR. 展开更多
关键词 Comblike polymer atom transfer radical polymerization (ATRP) MACROINITIATOR poly(methyl methacrylate) ethyl 2-bromoacrylate.
下载PDF
Combination analysis of hypermethylated SFRP1 and SFRP2 gene in fecal as a novel epigenetic biomarker panel for colorectal cancer screening 被引量:4
20
作者 Dong Tang Daorong Wang Hongbo Li 《Journal of Nanjing Medical University》 2008年第2期96-101,共6页
Objective:To investigate the feasibility of the combination of detecting hypermethylated secreted frizzled-related protein 1 (SFRP1) and secreted frizzled-related protein 2(SFRP2) in feces as a panel of biomarker... Objective:To investigate the feasibility of the combination of detecting hypermethylated secreted frizzled-related protein 1 (SFRP1) and secreted frizzled-related protein 2(SFRP2) in feces as a panel of biomarkers for colorectal cancer(CRC) screening. Methods: Methylation-specific PCR(MSP) was performed to analyze methylation status of SFRP1 and SFRP2 in a blinded fashion in tumor tissues and in matched stool samples from 39 patients with primary CRC, 34 patients with adenomas, 17 patients with hyperplastic polyps and 20 endoscopically normal subjects as normal controls. Simultaneously we analyzed the correlation of hypermethylated SFRP1 and SFRP2 with the clinicopathological features of CRC. Results:Hypermethylated SFRP1 was detected in 92.3%, 76.5%, 47.1% of tissue samples and in 89.7%, 64.7%, 35.3% of matched fecal samples from CRC, adenoma and hyperplastic polyp, respectively. Hypermethylated SFRP2 was detected in 87.2%, 67.6%, 35.3% of tissue samples and in 82.1%, 55.9%, 29.4% of matched fecal samples from CRC, adenoma and hyperplastic polyp, respectively. Of these two genes, at least one hypermethylated was 94.9%, 82.4%, 52.9% in tissue samples and 92.3%,73.5%, 47.1% in matched fecal samples from CRC, adenoma and hyperplastic polyp, respectively. In contrast, no hypermethylated SFRP1 and SFRP2 were detected in mucosa tissues of normal controls, only 2 cases of fecal samples was detected with hypermethylated SFRP1 and another 1 case was detected with hypermethylated SFRP2. Moreover, no significant associations were observed between hypermethylated SFRP1,SFRP2 and clinicopathological features of CRC. Conclusion: Hypermethylation of SFRP1 and SFRP2 in feces are novel epigenetic biomarkers of CRC and carded high potential for the remote detection of CRC as non-invasive screening method, and combined analysis of hypermethylated SFRP1 and SFRP2 in fecal could further increase the detection rate of CRC and premalignant lesions. 展开更多
关键词 Secreted frizzled-related protein I(SFRP1) secreted frizzled-related protein 2(SFRP2 methylation colorectal cancer feces
下载PDF
上一页 1 2 186 下一页 到第
使用帮助 返回顶部