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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
基金Supported by the Science and Technology Program of Panyu Central Hospital,No.PY-2023-003the Science and Technology Program of Panyu,No.2020-Z04-054+4 种基金the Science and Technology Project of the Guangzhou Health Commission,No.20211A011114the Science and Technology Program of Guangzhou,No.202002020023the General University Youth Innovative Talent Project of Guangdong Province,No.2022KQNCX281the Guangdong Provincial Key Field Special Project for Ordinary Colleges and Universities,No.2023ZDZX2097the Foshan Engineering Technology Research Center for Prepared Food Processing and Quality Evaluation,No.2022-KJZX113.
文摘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.
基金supported by National Natural Science Foundation of China (No.22102147 and 22002151)State Key Laboratory of Chemical Engineering (No.SKL-ChE-22A02)+2 种基金Zhejiang Provincial Natural Science Foundation of China under Grant No.LQ21B030009the Strategic Priority Research Program of the Chinese Academy of Sciences (No.XDA29050300)Qinchuang Yuan high-level innovation and entrepreneurship talents implementing project (No.QCYRCXM-2022-177)。
文摘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.
基金supported by the National Natural Science Foundation of China,Nos.82271283(to XC),91854115(to JW),31970044(to JW)the Natural Science Foundation of Beijing,No.7202001(to XC)the Scientific Research Project of Beijing Educational Committee,No.KM202010005022(to XC)。
文摘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.
基金The Grant from Programs of Science and Technology Commission Foundation of Jiangsu Province,No.BS2005036
文摘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.
文摘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.
文摘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.
基金financially supported by the National Natural Science Foundation of China(No.21171091)the Natural Science Foundation of Higher Education Institutions in Anhui Province(Nos.KJ2012A217,KJ2012B135,and KJ2012B136)
文摘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.
文摘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.
基金supported by the Natural Science Foundation of China (30570690 and 81041069)the Natural Science Foundation of Shanghai (08ZR1420700)
文摘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.
文摘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.
基金Supported by the Program for New Century Excellent Talents in University (NCET-04-0268)the Expertise-Introduction Project for Disciplinary Innovation of Universities
文摘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.
文摘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%.
文摘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.
基金financially supported by the Fundamental Research Funds for the Central Universities (No. FRF-BD-15-004A)
文摘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.
文摘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.
基金supported by the grant from Programs of Science and Technology Commission Foundation of Jiangsu Province(NO.BS2005036)
文摘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.