Preparing both safe and high-performance lithium-ion batteries(LIBs) based on commonly used commercial electrolytes is highly desirable,yet challenging.To overcome the poor compatibility of conventional small-molecula...Preparing both safe and high-performance lithium-ion batteries(LIBs) based on commonly used commercial electrolytes is highly desirable,yet challenging.To overcome the poor compatibility of conventional small-molecular flame-retardants as electrolyte additives for safe LIBs with graphite anodes,in this study,we propose and design a novel low-cost flame-retardant oligomer that achieves an accurate and complete reconciliation of fire safety and electrochemical performance in LIBs.Owing to the integration of phosphonate units and polyethylene glycol(PEG) chains,this oligomer,which is a phosphonatecontaining PEG-based oligomer(PPO),not only endows commercial electrolytes with excellent flame retardancy but also helps stabilize the electrodes and Li-ion migration.Specifically,adding 15 wt% of PPO can reduce 70% of the self-extinguishing time and 54% of total heat release for commercial electrolytes.Moreover,LiFePO_(4)/lithium and graphite/lithium cells as well as LiFePO_(4)/graphite pouch full cells exhibit good long-term cycling stability.展开更多
The capture and characterization of oligomers are extremely important in the studies of amyloid aggregation of proteins and peptides.Oligomers are critical intermediates that can impact the structures of amyloid fibri...The capture and characterization of oligomers are extremely important in the studies of amyloid aggregation of proteins and peptides.Oligomers are critical intermediates that can impact the structures of amyloid fibrils.Moreover,it is widely accepted that oligomers are the most toxic species along the aggregation pathway[1e4].The studies of oligomers are believed to shed light on the molecular mechanism of amyloid fibrillation and probably the medical clues for related diseases.In vitro investigations of amyloid oligomers are challenging due to their transient and polymorphic nature[5].This is particularly evident in the case of human type-2 diabetes-associated islet amyloid polypeptide(hIAPP),which tends to rapidly form polymorphic fibrils within minutes[6].Notably,hIAPP demonstrates a higher propensity for rapid aggregation compared to other amyloid proteins such as a-synuclein[7].展开更多
Background Coronary artery calcification(CAC)is common in end-stage renal disease(ESRD)patients,and the extent of CAC is closely related to cardiovascular outcomes in ESRD patients.Cartilage oligomeric matrix protein(...Background Coronary artery calcification(CAC)is common in end-stage renal disease(ESRD)patients,and the extent of CAC is closely related to cardiovascular outcomes in ESRD patients.Cartilage oligomeric matrix protein(COMP),as a component of the vascular matrix,has been found to be an inhibitor of arterial calcification in basic studies.However,there is no clinical research on the correlation between COMP and CAC in maintenance hemodialysis(MHD)patients.The aim of this study was to explore the relationship between serum COMP levels and CAC and cardiovascular events in MHD patients.Methods Serum COMP levels were compared between 54 MHD patients and 66 healthy people.MHD patients were then divided into three groups according to the tertiles of the concentration of COMP level and were followed up for major adverse cardiac events(MACEs),which were defined as a combined end point of new onset angina pectoris,nonfatal myocardial infarction,heart failure,coronary artery revascularization,hospitalization due to angina pectoris and all-cause deaths.The CAC score was calculated based on computed tomography scans.Results The serum COMP level in MHD patients was significantly higher than that in the general population[984.23(248.43-1902.61)ng/mL vs.219.01(97.26-821.92)ng/mL,P<0.01].Serum COMP levels were positively correlated with CAC(r=0.313,P=0.021)and serum parathyroid hormone in MHD patients(r=0.359,P<0.01).Linear regression suggested that after adjusting for age,fasting blood glucose(Glu)and glycosylated hemoglobin(HbAlc),CAC score was an independent predictor in the final model for COMP level(β=0.424,t=3.130,P<0.01).The receiver operating characteristic(ROC)curve showed that COMP≥994 mg/mL had 68.0%sensitivity and 72.4%specificity for the prediction of severe CAC[area under the curve(AUC):0.674,P=0.030,95%CI:0.526-0.882].After a median follow-up of 16 months(8-24 months),there was no difference in the incidence rate of MACEs between the upper,middle and lower serum COMP groups.Conclusions Our study found that MHD patients have higher levels of circulating COMP than controls.The serum COMP level is positively correlated with CAC score and could be used as a biomarker of severe CAC in MHD patients.However,there is no obvious correlation between serum COMP levels and the incidence of cardiovascular events.展开更多
The death of retinal ganglion cells is a hallmark of many optic neurodegenerative diseases such as glaucoma and retinopathy. Oxidative stress is one of the major reasons to cause the cell death. Oligomeric proanthocya...The death of retinal ganglion cells is a hallmark of many optic neurodegenerative diseases such as glaucoma and retinopathy. Oxidative stress is one of the major reasons to cause the cell death. Oligomeric proanthocyanidin has many health beneficial effects including antioxidative and neuro- protective actions. Here we tested whether oligomeric proanthocyanidin may protect retinal gan- glion cells against oxidative stress induced-apoptosis in vitro. Retinal ganglion cells were treated with hydrogen peroxide with or without oligomeric proanthocyanidin. 3-(4,5-Dimethylthiazol-2-yl)- 2,5-diphenyltetrazolium bromide (MTT) assay showed that treating retinal ganglion cell line RGC-5 cells with 20 pmol/L oligomeric proanthocyanidin significantly decreased the hydrogen peroxide (H202) induced death. Results of flow cytometry and Hoechst staining demonstrated that the death of RGC-5 cells was mainly caused by cell apoptosis. We further found that expression of pro-apoptotic Bax and caspase-3 were significantly decreased while anti-apoptotic Bcl-2 was greatly increased in H202 damaged RGC-5 cells with oligomeric proanthocyanidin by western blot assay. Furthermore, in retinal explant culture, the number of surviving retinal ganglion cells in H202-damaged retinal ganglion cells with oligomeric proanthocyanidin was significantly increased. Our studies thus demonstrate that oligomeric proanthocyanidin can protect oxidative stress-injured retinal ganglion cells by inhibiting apoptotic process.展开更多
Serum levels of cartilage oligomeric matrix protein(COMP) has been presented as a biomarker of liver fibrosis in several cross-sectional studies. COMP is also an essential mediator in carcinoma development and has als...Serum levels of cartilage oligomeric matrix protein(COMP) has been presented as a biomarker of liver fibrosis in several cross-sectional studies. COMP is also an essential mediator in carcinoma development and has also been associated with hepatocellular carcinoma. We present a prospective analysis of this biomarker in38 patients with chronic hepatitis C who were subject to eradication therapy with direct acting antivirals. We confirm previous studies associating COMP elevation with liver cirrhosis. We also show how viral levels are correlated with COMP at baseline. In our prospective analysis, we report that successful eradication of hepatitis C results in improvement in liver stiffness and laboratory liver function tests at 1 year follow-up. In contrast, median COMP-levels remain unchanged during the study period. We conclude that the biomarker potential of COMP in the prospective evaluation of liver diseases, remains to be elucidated.展开更多
Polyvinylcarbazole(PVK) composites containing organic-inorganic hybrid polyhedral oligomeric silse-squioxane(POSS) PVK-POSS were prepared by free radical polymerization. POSS monomers reacted with vinylcarbazole a...Polyvinylcarbazole(PVK) composites containing organic-inorganic hybrid polyhedral oligomeric silse-squioxane(POSS) PVK-POSS were prepared by free radical polymerization. POSS monomers reacted with vinylcarbazole and were completely dispersed at molecular level in PVK matrix and PVK-POSS nanocomposites display higher glass transition temperature(Tg) in comparison with neat PVK. Optical properties of PVK/POSS nanocomposites were investigated by UV-spectrum and PL-spectrum and the results show that the PVK-POSS nanoparticles have a good interface effect and improve color purity effectively. The maximum absorption wavelength bathochromically shifts gradually with the increasing of the content of POSS. The luminescent intensity becomes higher and higher with the increase of POSS content, and reaches its maximum luminescent intensity when the POSS content is 3% (mass fraction), while some POSS-rich nanoparticles are present in matrix when contents of POSS are beyond 5%.展开更多
AIM: Oligomeric proanthocyanidins (OPC), natural polyphenolic compounds found in plants, are known to have antioxidant and anti-cancer effects. We investigated whether the anti-cancer effects of the OPC are induced by...AIM: Oligomeric proanthocyanidins (OPC), natural polyphenolic compounds found in plants, are known to have antioxidant and anti-cancer effects. We investigated whether the anti-cancer effects of the OPC are induced by apoptosis on human colorectal cancer cell line, SNU-C4.METHODS: Colorectal cancer cell line, SNU-C4 was cultured in RPMI 1640 medium supplemented with 10% fetal bovine serum. The cytotoxic effect of OPC was assessed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenylt-etrazolium bromide (MTT) assay. To find out the apoptotic cell death, 4, 6-diamidino-2-phenylindole (DAPI) staining,terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay, reverse transcriptionpolymerase chain reaction (RT-PCR), and caspase-3 enzyme assay were performed.RESULTS: In this study, cytotoxic effect of OPC on SNUC4 cells appeared in a dose-dependent manner. OPC treatment (100 μg/mL) revealed typical morphological apoptotic features. Additionally OPC treatment (100 μg/mL)increased level of BAX and CASPASE-3, and decreased level of BCL-2 mRNA expression. Caspase-3 enzyme activity was also significantly increased by treatment of OPC (100 μg/mL) compared with control.CONCLUSION: These data indicate that OPC caused cell death by apoptosis through caspase pathways on human colorectal cancer cell line, SNU-C4.展开更多
A first-principles computational method based on the hybrid density functional theory is developed to simulate the electronic transport properties of oligomeric phenylene ethynylene molecular junctions with H2O molecu...A first-principles computational method based on the hybrid density functional theory is developed to simulate the electronic transport properties of oligomeric phenylene ethynylene molecular junctions with H2O molecules accumulated in the vicinity as recently reported by Na et al. [Nanotechnology 18 424001 (2007)]. The numerical results show that the hydrogen bonds between the oxygen atoms of the oligomeric phenylene ethynylene molecule and H2O molecules result in the localisation of the molecular orbitals and lead to the lower transition peaks. The H2O molecular chains accumulated in the vicinity of the molecular junction can not only change the electronic structure of the molecular junctions, but also open additional electronic transport pathways. The obvious influence of H2O molecules on the electronic structure of the molecular junction and its electronic transport properties is thus demonstrated.展开更多
The flame-retarded polycarbonate(PC) has been made with octaphenyl polyhedral silsesquioxane(OPS) and/or caged bicyclic phosphate(Trimer).Thermal gravimetric analysis(TGA),Fourier-transform infrared(FTIR),TG...The flame-retarded polycarbonate(PC) has been made with octaphenyl polyhedral silsesquioxane(OPS) and/or caged bicyclic phosphate(Trimer).Thermal gravimetric analysis(TGA),Fourier-transform infrared(FTIR),TGA-FTIR,limiting oxygen index(LOI),and mechanical tests have been employed to characterize the modified PC.The additives of OPS and Trimer in PC have been proved to be effective flame-retardants because of the synergistic interaction between the elements of P and Si.The role of OPS and Trimer in PC degradation are different:OPS participates in the charring of PC,while Trimer makes PC degrade in advance.In addition,OPS and Trimer induced obvious differences in the mechanical properties of PC.展开更多
Six nonionic oligomeric manganese ( Ⅱ ) complexes with oligomeric phosphate-polyglycol-EDTA ester ligands were synthesized and characterized. The longitudinal relaxivities of these complexes were measured. One of t...Six nonionic oligomeric manganese ( Ⅱ ) complexes with oligomeric phosphate-polyglycol-EDTA ester ligands were synthesized and characterized. The longitudinal relaxivities of these complexes were measured. One of these complexes, which showed the highest relaxivity, was chosen to be used in the acute toxicity test and the T1-weighted imaging experiment. It has been found that compared to Gd-DTPA, this nonionic oligomeric Mn( Ⅱ ) complex exhibits no acute toxicity, generates highly enhanced MRI signals and increases the intention time in the rat liver tissue.展开更多
Escherichia coli 3-Deoxy-D-manno-octulosonate 8-phosphate(KDO8P) synthase catalyzed the condensation reaction between D-arabinose 5-phosphate(A5P) and phosphoenolpyruvate(PEP) to form KDO8P and inorganic phosph...Escherichia coli 3-Deoxy-D-manno-octulosonate 8-phosphate(KDO8P) synthase catalyzed the condensation reaction between D-arabinose 5-phosphate(A5P) and phosphoenolpyruvate(PEP) to form KDO8P and inorganic phosphate(Pi). The noncovalent tetrameric association ofKDO8P synthase was observed and dissociated in gas phase by means of electrospray ionization mass spectrometry under the very "soft" conditions. The results indicate that PEP-bound enzyme generated abundant tetrameric species as well as monomeric species at the "soft" conditions, whereas, the unbound enzyme favored the formation of a dimeric species. The mass spectra of the mixture of the enzyme with one of substrates, PEP, and A5P or one of products, KDO8P and Pi show that the complex of the unbound enzyme with PEP or Pi was prone to the formation of a monomeric species, whereas, that of the unbound enzyme with A5P or KDO8P was similar to the unbound enzyme. The intensity of the dimeric species increased with the increase of temperature at a collision voltage of 10 V. Taken together, the results presented here suggest that mass spectrometry will be a powerful tool to explore subtile conformational changes and/or subunit-subunit interactions of multiprotein assembly induced by ligand-binding and/or the changes of environmental conditions.展开更多
Hepatitis C virus(HCV)is a major cause of viral hepatitis and currently infects approximately 170 million people worldwide.An infection by HCV causes high rates of chronic hepatitis(>75%)and progresses to liver cir...Hepatitis C virus(HCV)is a major cause of viral hepatitis and currently infects approximately 170 million people worldwide.An infection by HCV causes high rates of chronic hepatitis(>75%)and progresses to liver cirrhosis and hepatocellular carcinoma ultimately.HCV can be eliminated by a combination of pegylatedα-interferon and the broad-spectrum antiviral drug ribavirin;however,this treatment is still associated with poor efficacy and tolerability and is often accompanied by serious side-effects.While some novel direct-actingantivirals against HCV have been developed recently,high medical costs limit the access to the therapy in cost-sensitive countries.To search for new natural anti-HCV agents,we screened local agricultural products for their suppressive activities against HCV replication using the HCV replicon cell system in vitro.We found a potent inhibitor of HCV RNA expression in the extracts of blueberry leaves and then identified oligomeric proanthocyanidin as the active ingredient.Further investigations into the action mechanism of oligomeric proanthocyanidin suggested that it is an inhibitor of heterogeneous nuclear ribonucleoproteins(hn RNPs)such as hn RNP A2/B1.In this review,we presented an overview of functional foods and ingredients efficient for HCV infection,the chemical structural characteristics of oligomeric proanthocyanidin,and its action mechanism.展开更多
The active catalysts of the BF_(3)/n-C_(4)H_(9)OH-catalyzed 1-decene oligomerization reaction,as well as the distribution of the reaction products,was investigated by molecular simulation.The calculation results show ...The active catalysts of the BF_(3)/n-C_(4)H_(9)OH-catalyzed 1-decene oligomerization reaction,as well as the distribution of the reaction products,was investigated by molecular simulation.The calculation results show that(BF_(3))_(2)·n-C_(4)H_(9)OH catalyzes the 1-decene oligomerization reaction with higher activity compared to BF_(3)·n-C_(4)H_(9)OH,which is the most catalytically active substance in the BF_(3)/n-C_(4)H_(9)OH catalyst system.The reaction energy barriers and heats of reaction of chain initiation,chain growth,and chain termination in BF_(3)/n-C_(4)H_(9)OH-catalyzed 1-decene oligomerization are calculated to reveal the product distribution.The calculation results show that the contents of the oligomerization reaction products in descending order are trimer,tetramer,pentamer,and dimer.The calculated results were consistent with the experimentally obtained product distribution.展开更多
基金supported by the National Natural Science Foundation of China (51773134, U19A2095)the Sichuan Science and Technology Program (2019YFH0112)+2 种基金the Fundamental Research Funds for the Central UniversitiesInstitutional Research Fund from Sichuan University (2021SCUNL201)the 111 Project (B20001)。
文摘Preparing both safe and high-performance lithium-ion batteries(LIBs) based on commonly used commercial electrolytes is highly desirable,yet challenging.To overcome the poor compatibility of conventional small-molecular flame-retardants as electrolyte additives for safe LIBs with graphite anodes,in this study,we propose and design a novel low-cost flame-retardant oligomer that achieves an accurate and complete reconciliation of fire safety and electrochemical performance in LIBs.Owing to the integration of phosphonate units and polyethylene glycol(PEG) chains,this oligomer,which is a phosphonatecontaining PEG-based oligomer(PPO),not only endows commercial electrolytes with excellent flame retardancy but also helps stabilize the electrodes and Li-ion migration.Specifically,adding 15 wt% of PPO can reduce 70% of the self-extinguishing time and 54% of total heat release for commercial electrolytes.Moreover,LiFePO_(4)/lithium and graphite/lithium cells as well as LiFePO_(4)/graphite pouch full cells exhibit good long-term cycling stability.
文摘The capture and characterization of oligomers are extremely important in the studies of amyloid aggregation of proteins and peptides.Oligomers are critical intermediates that can impact the structures of amyloid fibrils.Moreover,it is widely accepted that oligomers are the most toxic species along the aggregation pathway[1e4].The studies of oligomers are believed to shed light on the molecular mechanism of amyloid fibrillation and probably the medical clues for related diseases.In vitro investigations of amyloid oligomers are challenging due to their transient and polymorphic nature[5].This is particularly evident in the case of human type-2 diabetes-associated islet amyloid polypeptide(hIAPP),which tends to rapidly form polymorphic fibrils within minutes[6].Notably,hIAPP demonstrates a higher propensity for rapid aggregation compared to other amyloid proteins such as a-synuclein[7].
基金supported by the National Natural Science Foundation of China(81400262)the Backbone Fund of Peking University Third Hospital(Y72497-04)
文摘Background Coronary artery calcification(CAC)is common in end-stage renal disease(ESRD)patients,and the extent of CAC is closely related to cardiovascular outcomes in ESRD patients.Cartilage oligomeric matrix protein(COMP),as a component of the vascular matrix,has been found to be an inhibitor of arterial calcification in basic studies.However,there is no clinical research on the correlation between COMP and CAC in maintenance hemodialysis(MHD)patients.The aim of this study was to explore the relationship between serum COMP levels and CAC and cardiovascular events in MHD patients.Methods Serum COMP levels were compared between 54 MHD patients and 66 healthy people.MHD patients were then divided into three groups according to the tertiles of the concentration of COMP level and were followed up for major adverse cardiac events(MACEs),which were defined as a combined end point of new onset angina pectoris,nonfatal myocardial infarction,heart failure,coronary artery revascularization,hospitalization due to angina pectoris and all-cause deaths.The CAC score was calculated based on computed tomography scans.Results The serum COMP level in MHD patients was significantly higher than that in the general population[984.23(248.43-1902.61)ng/mL vs.219.01(97.26-821.92)ng/mL,P<0.01].Serum COMP levels were positively correlated with CAC(r=0.313,P=0.021)and serum parathyroid hormone in MHD patients(r=0.359,P<0.01).Linear regression suggested that after adjusting for age,fasting blood glucose(Glu)and glycosylated hemoglobin(HbAlc),CAC score was an independent predictor in the final model for COMP level(β=0.424,t=3.130,P<0.01).The receiver operating characteristic(ROC)curve showed that COMP≥994 mg/mL had 68.0%sensitivity and 72.4%specificity for the prediction of severe CAC[area under the curve(AUC):0.674,P=0.030,95%CI:0.526-0.882].After a median follow-up of 16 months(8-24 months),there was no difference in the incidence rate of MACEs between the upper,middle and lower serum COMP groups.Conclusions Our study found that MHD patients have higher levels of circulating COMP than controls.The serum COMP level is positively correlated with CAC score and could be used as a biomarker of severe CAC in MHD patients.However,there is no obvious correlation between serum COMP levels and the incidence of cardiovascular events.
基金supported by grants from theNational Basic Research Program of China,No.973Program,2011CB707501the Natural Science Foundation of Guangdong Province,China,No.S2012010008874+1 种基金the Natural Science Foundation of Guangzhou,China,No.11BppZXaa2070006,D.X.Lthe National Natural Science Foundation of China,No.81100669
文摘The death of retinal ganglion cells is a hallmark of many optic neurodegenerative diseases such as glaucoma and retinopathy. Oxidative stress is one of the major reasons to cause the cell death. Oligomeric proanthocyanidin has many health beneficial effects including antioxidative and neuro- protective actions. Here we tested whether oligomeric proanthocyanidin may protect retinal gan- glion cells against oxidative stress induced-apoptosis in vitro. Retinal ganglion cells were treated with hydrogen peroxide with or without oligomeric proanthocyanidin. 3-(4,5-Dimethylthiazol-2-yl)- 2,5-diphenyltetrazolium bromide (MTT) assay showed that treating retinal ganglion cell line RGC-5 cells with 20 pmol/L oligomeric proanthocyanidin significantly decreased the hydrogen peroxide (H202) induced death. Results of flow cytometry and Hoechst staining demonstrated that the death of RGC-5 cells was mainly caused by cell apoptosis. We further found that expression of pro-apoptotic Bax and caspase-3 were significantly decreased while anti-apoptotic Bcl-2 was greatly increased in H202 damaged RGC-5 cells with oligomeric proanthocyanidin by western blot assay. Furthermore, in retinal explant culture, the number of surviving retinal ganglion cells in H202-damaged retinal ganglion cells with oligomeric proanthocyanidin was significantly increased. Our studies thus demonstrate that oligomeric proanthocyanidin can protect oxidative stress-injured retinal ganglion cells by inhibiting apoptotic process.
基金Bengt Ihre Foundation,No.SLS-594-301 and SLS-789091
文摘Serum levels of cartilage oligomeric matrix protein(COMP) has been presented as a biomarker of liver fibrosis in several cross-sectional studies. COMP is also an essential mediator in carcinoma development and has also been associated with hepatocellular carcinoma. We present a prospective analysis of this biomarker in38 patients with chronic hepatitis C who were subject to eradication therapy with direct acting antivirals. We confirm previous studies associating COMP elevation with liver cirrhosis. We also show how viral levels are correlated with COMP at baseline. In our prospective analysis, we report that successful eradication of hepatitis C results in improvement in liver stiffness and laboratory liver function tests at 1 year follow-up. In contrast, median COMP-levels remain unchanged during the study period. We conclude that the biomarker potential of COMP in the prospective evaluation of liver diseases, remains to be elucidated.
基金Beijing Natural Science Foundation(No.2072015)the National High Technology Research and Development Program of China(No.2006AA032563).
文摘Polyvinylcarbazole(PVK) composites containing organic-inorganic hybrid polyhedral oligomeric silse-squioxane(POSS) PVK-POSS were prepared by free radical polymerization. POSS monomers reacted with vinylcarbazole and were completely dispersed at molecular level in PVK matrix and PVK-POSS nanocomposites display higher glass transition temperature(Tg) in comparison with neat PVK. Optical properties of PVK/POSS nanocomposites were investigated by UV-spectrum and PL-spectrum and the results show that the PVK-POSS nanoparticles have a good interface effect and improve color purity effectively. The maximum absorption wavelength bathochromically shifts gradually with the increasing of the content of POSS. The luminescent intensity becomes higher and higher with the increase of POSS content, and reaches its maximum luminescent intensity when the POSS content is 3% (mass fraction), while some POSS-rich nanoparticles are present in matrix when contents of POSS are beyond 5%.
文摘AIM: Oligomeric proanthocyanidins (OPC), natural polyphenolic compounds found in plants, are known to have antioxidant and anti-cancer effects. We investigated whether the anti-cancer effects of the OPC are induced by apoptosis on human colorectal cancer cell line, SNU-C4.METHODS: Colorectal cancer cell line, SNU-C4 was cultured in RPMI 1640 medium supplemented with 10% fetal bovine serum. The cytotoxic effect of OPC was assessed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenylt-etrazolium bromide (MTT) assay. To find out the apoptotic cell death, 4, 6-diamidino-2-phenylindole (DAPI) staining,terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay, reverse transcriptionpolymerase chain reaction (RT-PCR), and caspase-3 enzyme assay were performed.RESULTS: In this study, cytotoxic effect of OPC on SNUC4 cells appeared in a dose-dependent manner. OPC treatment (100 μg/mL) revealed typical morphological apoptotic features. Additionally OPC treatment (100 μg/mL)increased level of BAX and CASPASE-3, and decreased level of BCL-2 mRNA expression. Caspase-3 enzyme activity was also significantly increased by treatment of OPC (100 μg/mL) compared with control.CONCLUSION: These data indicate that OPC caused cell death by apoptosis through caspase pathways on human colorectal cancer cell line, SNU-C4.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.10804064 and 10674084)
文摘A first-principles computational method based on the hybrid density functional theory is developed to simulate the electronic transport properties of oligomeric phenylene ethynylene molecular junctions with H2O molecules accumulated in the vicinity as recently reported by Na et al. [Nanotechnology 18 424001 (2007)]. The numerical results show that the hydrogen bonds between the oxygen atoms of the oligomeric phenylene ethynylene molecule and H2O molecules result in the localisation of the molecular orbitals and lead to the lower transition peaks. The H2O molecular chains accumulated in the vicinity of the molecular junction can not only change the electronic structure of the molecular junctions, but also open additional electronic transport pathways. The obvious influence of H2O molecules on the electronic structure of the molecular junction and its electronic transport properties is thus demonstrated.
基金Sponsored by the National High Technology Research and Development Program of China("863"Program)(2007AA03Z538)
文摘The flame-retarded polycarbonate(PC) has been made with octaphenyl polyhedral silsesquioxane(OPS) and/or caged bicyclic phosphate(Trimer).Thermal gravimetric analysis(TGA),Fourier-transform infrared(FTIR),TGA-FTIR,limiting oxygen index(LOI),and mechanical tests have been employed to characterize the modified PC.The additives of OPS and Trimer in PC have been proved to be effective flame-retardants because of the synergistic interaction between the elements of P and Si.The role of OPS and Trimer in PC degradation are different:OPS participates in the charring of PC,while Trimer makes PC degrade in advance.In addition,OPS and Trimer induced obvious differences in the mechanical properties of PC.
基金Supported by the National Natural Science Foundation of China(Nos. 20275011 and 10234070) the Program for PromotingUniversity Academic Excellence by the Ministry of Education of Taiwan of China(No. A-92-N-FA01-2-4-5) Foundation of StateKey Laboratory of Magnetic Resonance &Atomic and Molecular Physics(No. T12045).
文摘Six nonionic oligomeric manganese ( Ⅱ ) complexes with oligomeric phosphate-polyglycol-EDTA ester ligands were synthesized and characterized. The longitudinal relaxivities of these complexes were measured. One of these complexes, which showed the highest relaxivity, was chosen to be used in the acute toxicity test and the T1-weighted imaging experiment. It has been found that compared to Gd-DTPA, this nonionic oligomeric Mn( Ⅱ ) complex exhibits no acute toxicity, generates highly enhanced MRI signals and increases the intention time in the rat liver tissue.
基金Supported by National Hi-tech Research and Development Program of China(No.2006AA02Z154)the National Natural Science Foundation of China(No.20675088) and SRF for ROCS, SEM, China
文摘Escherichia coli 3-Deoxy-D-manno-octulosonate 8-phosphate(KDO8P) synthase catalyzed the condensation reaction between D-arabinose 5-phosphate(A5P) and phosphoenolpyruvate(PEP) to form KDO8P and inorganic phosphate(Pi). The noncovalent tetrameric association ofKDO8P synthase was observed and dissociated in gas phase by means of electrospray ionization mass spectrometry under the very "soft" conditions. The results indicate that PEP-bound enzyme generated abundant tetrameric species as well as monomeric species at the "soft" conditions, whereas, the unbound enzyme favored the formation of a dimeric species. The mass spectra of the mixture of the enzyme with one of substrates, PEP, and A5P or one of products, KDO8P and Pi show that the complex of the unbound enzyme with PEP or Pi was prone to the formation of a monomeric species, whereas, that of the unbound enzyme with A5P or KDO8P was similar to the unbound enzyme. The intensity of the dimeric species increased with the increase of temperature at a collision voltage of 10 V. Taken together, the results presented here suggest that mass spectrometry will be a powerful tool to explore subtile conformational changes and/or subunit-subunit interactions of multiprotein assembly induced by ligand-binding and/or the changes of environmental conditions.
基金Supported by The Collaboration of Regional Entities for the Advancement of Technological Excellence from Japan Science and Technology Agency
文摘Hepatitis C virus(HCV)is a major cause of viral hepatitis and currently infects approximately 170 million people worldwide.An infection by HCV causes high rates of chronic hepatitis(>75%)and progresses to liver cirrhosis and hepatocellular carcinoma ultimately.HCV can be eliminated by a combination of pegylatedα-interferon and the broad-spectrum antiviral drug ribavirin;however,this treatment is still associated with poor efficacy and tolerability and is often accompanied by serious side-effects.While some novel direct-actingantivirals against HCV have been developed recently,high medical costs limit the access to the therapy in cost-sensitive countries.To search for new natural anti-HCV agents,we screened local agricultural products for their suppressive activities against HCV replication using the HCV replicon cell system in vitro.We found a potent inhibitor of HCV RNA expression in the extracts of blueberry leaves and then identified oligomeric proanthocyanidin as the active ingredient.Further investigations into the action mechanism of oligomeric proanthocyanidin suggested that it is an inhibitor of heterogeneous nuclear ribonucleoproteins(hn RNPs)such as hn RNP A2/B1.In this review,we presented an overview of functional foods and ingredients efficient for HCV infection,the chemical structural characteristics of oligomeric proanthocyanidin,and its action mechanism.
基金This work was financially supported by China Petrochemical Corporation Project(120055).
文摘The active catalysts of the BF_(3)/n-C_(4)H_(9)OH-catalyzed 1-decene oligomerization reaction,as well as the distribution of the reaction products,was investigated by molecular simulation.The calculation results show that(BF_(3))_(2)·n-C_(4)H_(9)OH catalyzes the 1-decene oligomerization reaction with higher activity compared to BF_(3)·n-C_(4)H_(9)OH,which is the most catalytically active substance in the BF_(3)/n-C_(4)H_(9)OH catalyst system.The reaction energy barriers and heats of reaction of chain initiation,chain growth,and chain termination in BF_(3)/n-C_(4)H_(9)OH-catalyzed 1-decene oligomerization are calculated to reveal the product distribution.The calculation results show that the contents of the oligomerization reaction products in descending order are trimer,tetramer,pentamer,and dimer.The calculated results were consistent with the experimentally obtained product distribution.