Methacrylic acid,an important organic chemical,is commercially manufactured starting from fossil feedstock.The decarboxylation of itaconic acid derived for biomass is a green route to the synthesis of methacrylic acid...Methacrylic acid,an important organic chemical,is commercially manufactured starting from fossil feedstock.The decarboxylation of itaconic acid derived for biomass is a green route to the synthesis of methacrylic acid.In view of the problems existing in the researches on this route such as use of noble metal catalyst,harsh reaction conditions and low desired-product yield,we prepared a series of hydroxyapatite catalysts with different Ca/P molar ratios and evaluated their catalytic performance.The results showed that the hydroxyapatite catalyst with a Ca/P molar ratio of 1.58 had the best catalytic activity.The highest yield of MAA up to 61.2%was achieved with basically complete conversion of itaconic acid under the suitable reaction conditions of 1 equivalent of NaOH,2 MPa of N_(2),250℃,and 2 h.On this basis,a reaction network for the decarboxylation of itaconic acid to methacrylic acid catalyzed by hydroxyapatite was established.With the aid of catalyst characterization using X-ray powder diffraction,NH3/CO2 temperature-programmed desorption,N_(2)physisorption,inductively coupled plasma optical emission spectrometry,and scanning electron microscopy,we found that the distribution of surface acid sites and basic sites,crystal growth orientation,texture properties and morphology of hydroxyapatite varied with the Ca/P molar ratio.Furthermore,the change of the crystal growth orientation and its influence on the surface acidity and alkalinity were clarified.展开更多
BACKGROUND:p130Cas(p130Crk-associated substance) is a junction protein that is important to the adhesion between cytoskeleton and extracellular matrix.Also the adhesion molecules E-cadherin andβ-catenin play importan...BACKGROUND:p130Cas(p130Crk-associated substance) is a junction protein that is important to the adhesion between cytoskeleton and extracellular matrix.Also the adhesion molecules E-cadherin andβ-catenin play important roles in the invasiveness of carcinoma.This study was undertaken to investigate the effects of p130Cas E-cadherin andβ-catenin on the invasion,metastasis and prognosis of hepatocellular carcinoma(HCC). METHODS:Immunohistochemistry was used to evaluate the expression of p130Cas,E-cadherin,andβ-catenin in 40 patients with HCC.All patients were followed up postoperatively,and the relationship between expression and clinicopathological prognostic parameters was analyzed RESULTS:The positive expression rates of p130Cas and E-cadherin in HCC tissue(n=40)were 62.50%and 55.00% but in normal liver tissue 10%,and 100%,respectively (P<0.05).The abnormal expression rate ofβ-catenin in HCC tissue was 70%,while in normal liver tissue it was 13.33%(P<0.05).The positive rate of p130Cas was correlated with lymph node invasion,pathological stage TNM stage,and a worse prognosis,but not with gender age,HBV infection,hepatic cirrhosis,alpha-fetoprotein (AFP)level before operation,and tumor diameter Similarly,the expression of E-cadherin andβ-catenin was correlated with lymph node invasion,pathological stage,TNM stage,and worse prognosis,but not with gender,age,HBV infection,hepatic cirrhosis,AFP level before operation,and tumor size.Correlations were found between p130Cas and abnormal E-cadherin/β-catenin expression(P<0.001 and<0.05,respectively).CONCLUSIONS:In HCC,there is a negative correlation between the positive expression of p130Cas and the normal expression of the adhesion molecules E-cadherin/β-catenin, and p130Cas plays important roles in the invasion, metastasis and prognosis of HCC.p130Cas may be involved in alterating the structure and function of E-cadherin/ β-catenin,by regulating tyrosine phosphorylation via the p130Cas-Src signal pathway.展开更多
BACKGROUND Studies have shown that long non-coding RNAs(lncRNAs)play a key role in almost all key physiological and pathological processes,including different types of malignant tumors.Our previous lncRNA microarray r...BACKGROUND Studies have shown that long non-coding RNAs(lncRNAs)play a key role in almost all key physiological and pathological processes,including different types of malignant tumors.Our previous lncRNA microarray results have shown that lncRNA XLOC_001659 is upregulated in esophageal cancer(EC)tissues,with a fold change of 20.9 relative to normal esophageal tissues.But its effect and the molecular biological mechanisms on proliferation and invasion of EC cells remain unclear.AIM To investigate the effect of lncRNA XLOC_001659 on esophageal squamous cell carcinoma(ESCC)cells and explore the molecular biological mechanisms involved.METHODS RT-qPCR assay was used to quantify the expression levels of lncRNAXLOC-001659 and miR-490-5p.The proliferative capacity of the cells was determined using CCK8 and colony formation assays,and the effect of lncRNAXLOC-001659 on the invasion of ESCC cells was determined by Transwell assay.Dualluciferase reporter assay was used to detect the target genes of lncRNAXLOC-001659 and miR-490-5p.RESULTS The results of RT-qPCR showed that the expression of lncRNAXLOC_001659 was upregulated in ESCC cells.CCK-8 assay showed that knockdown of lncRNAXLOC_001659 significantly inhibited ESCC cell proliferation.Colony formation and Transwell invasion assays showed that knockdown of lncRNAXLOC_001659 or overexpression of miR-490-5p significantly inhibited ESCC cell growth and invasion.Furthermore,lncRNAXLOC_001659 acts as an endogenous sponge by competitively binding to miR-490-5p to downregulate miR-490-5p.Further results confirmed that miR-490-5p targeted PIK3CA,and the recovery of PIK3CA rescued lncRNAXLOC_001659 knockdown or miR-490-5p overexpression-mediated inhibition of cell proliferation and invasion,which suggested the presence of an lncRNAXLOC_001659/miR-490-5p/PIK3CA regulatory axis.CONCLUSION Knockdown of lncRNA XLOC_001659 inhibits proliferation and invasion of ESCC cells via regulation of miR-490-5p/PIK3CA,suggesting that it may play a role in ESCC tumorigenesis and progression.展开更多
Synchrotron radiation X-ray fluorescence （SR-XRF） approach was applied to analyzing of Chinstrap penguin （ Pygoscelis Antarctica） cortical bone. The method enabled the in situ determination of Ca and P concentrati...Synchrotron radiation X-ray fluorescence （SR-XRF） approach was applied to analyzing of Chinstrap penguin （ Pygoscelis Antarctica） cortical bone. The method enabled the in situ determination of Ca and P concentrations and the Ca/P ratio in cortical bone. The preliminary results show that ： （ 1 ） there is the bone site-related difference for Ca and P concentrations. The mean values for the investigated parameters （ on a dry-weight basis） are： 30.7% （Ca） and 14.9% （P） for the femoral cortical bone, 21.4% （Ca） and 11.5% （P） for wing cortical bone. （2） The variation for the Ca/P ratio in cortical bone is lower than those for Ca and P separately. This is in agreement with the previous report that the specificity of the Ca/P ratio is better than that of Ca and P concentrations and is more reliable for the diagnosis of bone disorders. The authors suggest that further studies be conducted to establish norreal values of Ca, P and Ca/P ratio for polar animals and provide a basis for the diagnosis of bone disorders.展开更多
Desert plants take on unique physiologically adaptive mechanisms in response to an adverse environment. In this study, we determined the concentrations of leaf nitrogen(N), phosphorus(P), and calcium(Ca) fraction for ...Desert plants take on unique physiologically adaptive mechanisms in response to an adverse environment. In this study, we determined the concentrations of leaf nitrogen(N), phosphorus(P), and calcium(Ca) fraction for dominant species of Artemisia ordosica, A. frigida, Calligonum mongolicum, and Oxytropis aciphylla in the Alxa Desert and discussed seasonal changes of their leaf N:P ratio and Ca fraction. The results showed that, from May to September, the N:P ratios of A. ordosica and C. mongolicum gradually and significantly increased, while those of A. frigida, and O. aciphylla had an increase trend that was not significant; the physiologically active Ca of A. ordosica and A. frigida increased significantly,while that of C. mongolicum and O. aciphylla decreased significantly. The physiologically inert calcium of C. mongolicum increased extremely significantly, while that of others was not significant. There was a significantly positive correlation between the N:P ratio and physiologically active Ca for A. ordosica, and the N:P ratio was significantly and negatively correlated with physiologically active Ca for O. aciphylla. These findings revealed that the physiological regulation mechanism was different for the plants either in earlier stage or later stage of plant-community succession.展开更多
An experiment on the phosphorus requirement and the proper Ca/P ratio in the diet of the black sea bream using the phosphorus gradient method (with casein as basic diet, sodium dihydrogen phosphate as source of phosph...An experiment on the phosphorus requirement and the proper Ca/P ratio in the diet of the black sea bream using the phosphorus gradient method (with casein as basic diet, sodium dihydrogen phosphate as source of phosphorus, and calcium lactate as source of calcium) showed that growth was greatly affected by the diet’s phosphorus content and Ca/P ratio. Inadequate phosphorus in the diet resulted in slow growth and poor food conversion ratio (FCR). Analyses of the fish body showed it contained a high level of lipid but a low level of moisture, ash, calcium and phosphorus. The optimal values of phosphorus and Ca/P ratio in the black sea bream diet are 0.68% and 1:2 respectively. Phosphorus in excess of this optimum value resulted in slow growth or even death. The results of this experiment clearly indicated that phosphorus is the principal mineral additive affecting black sea bream growth.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.21978066)Basic Research Program of Hebei Province for Natural Science Foundation and Key Basic Research Project(Grant No.18964308D)the Key Program of Natural Science Foundation of Hebei Province(Grant No.B2020202048).
文摘Methacrylic acid,an important organic chemical,is commercially manufactured starting from fossil feedstock.The decarboxylation of itaconic acid derived for biomass is a green route to the synthesis of methacrylic acid.In view of the problems existing in the researches on this route such as use of noble metal catalyst,harsh reaction conditions and low desired-product yield,we prepared a series of hydroxyapatite catalysts with different Ca/P molar ratios and evaluated their catalytic performance.The results showed that the hydroxyapatite catalyst with a Ca/P molar ratio of 1.58 had the best catalytic activity.The highest yield of MAA up to 61.2%was achieved with basically complete conversion of itaconic acid under the suitable reaction conditions of 1 equivalent of NaOH,2 MPa of N_(2),250℃,and 2 h.On this basis,a reaction network for the decarboxylation of itaconic acid to methacrylic acid catalyzed by hydroxyapatite was established.With the aid of catalyst characterization using X-ray powder diffraction,NH3/CO2 temperature-programmed desorption,N_(2)physisorption,inductively coupled plasma optical emission spectrometry,and scanning electron microscopy,we found that the distribution of surface acid sites and basic sites,crystal growth orientation,texture properties and morphology of hydroxyapatite varied with the Ca/P molar ratio.Furthermore,the change of the crystal growth orientation and its influence on the surface acidity and alkalinity were clarified.
文摘BACKGROUND:p130Cas(p130Crk-associated substance) is a junction protein that is important to the adhesion between cytoskeleton and extracellular matrix.Also the adhesion molecules E-cadherin andβ-catenin play important roles in the invasiveness of carcinoma.This study was undertaken to investigate the effects of p130Cas E-cadherin andβ-catenin on the invasion,metastasis and prognosis of hepatocellular carcinoma(HCC). METHODS:Immunohistochemistry was used to evaluate the expression of p130Cas,E-cadherin,andβ-catenin in 40 patients with HCC.All patients were followed up postoperatively,and the relationship between expression and clinicopathological prognostic parameters was analyzed RESULTS:The positive expression rates of p130Cas and E-cadherin in HCC tissue(n=40)were 62.50%and 55.00% but in normal liver tissue 10%,and 100%,respectively (P<0.05).The abnormal expression rate ofβ-catenin in HCC tissue was 70%,while in normal liver tissue it was 13.33%(P<0.05).The positive rate of p130Cas was correlated with lymph node invasion,pathological stage TNM stage,and a worse prognosis,but not with gender age,HBV infection,hepatic cirrhosis,alpha-fetoprotein (AFP)level before operation,and tumor diameter Similarly,the expression of E-cadherin andβ-catenin was correlated with lymph node invasion,pathological stage,TNM stage,and worse prognosis,but not with gender,age,HBV infection,hepatic cirrhosis,AFP level before operation,and tumor size.Correlations were found between p130Cas and abnormal E-cadherin/β-catenin expression(P<0.001 and<0.05,respectively).CONCLUSIONS:In HCC,there is a negative correlation between the positive expression of p130Cas and the normal expression of the adhesion molecules E-cadherin/β-catenin, and p130Cas plays important roles in the invasion, metastasis and prognosis of HCC.p130Cas may be involved in alterating the structure and function of E-cadherin/ β-catenin,by regulating tyrosine phosphorylation via the p130Cas-Src signal pathway.
基金Supported by Excellent Youth Development Fund of Zhengzhou University,No.1621328001
文摘BACKGROUND Studies have shown that long non-coding RNAs(lncRNAs)play a key role in almost all key physiological and pathological processes,including different types of malignant tumors.Our previous lncRNA microarray results have shown that lncRNA XLOC_001659 is upregulated in esophageal cancer(EC)tissues,with a fold change of 20.9 relative to normal esophageal tissues.But its effect and the molecular biological mechanisms on proliferation and invasion of EC cells remain unclear.AIM To investigate the effect of lncRNA XLOC_001659 on esophageal squamous cell carcinoma(ESCC)cells and explore the molecular biological mechanisms involved.METHODS RT-qPCR assay was used to quantify the expression levels of lncRNAXLOC-001659 and miR-490-5p.The proliferative capacity of the cells was determined using CCK8 and colony formation assays,and the effect of lncRNAXLOC-001659 on the invasion of ESCC cells was determined by Transwell assay.Dualluciferase reporter assay was used to detect the target genes of lncRNAXLOC-001659 and miR-490-5p.RESULTS The results of RT-qPCR showed that the expression of lncRNAXLOC_001659 was upregulated in ESCC cells.CCK-8 assay showed that knockdown of lncRNAXLOC_001659 significantly inhibited ESCC cell proliferation.Colony formation and Transwell invasion assays showed that knockdown of lncRNAXLOC_001659 or overexpression of miR-490-5p significantly inhibited ESCC cell growth and invasion.Furthermore,lncRNAXLOC_001659 acts as an endogenous sponge by competitively binding to miR-490-5p to downregulate miR-490-5p.Further results confirmed that miR-490-5p targeted PIK3CA,and the recovery of PIK3CA rescued lncRNAXLOC_001659 knockdown or miR-490-5p overexpression-mediated inhibition of cell proliferation and invasion,which suggested the presence of an lncRNAXLOC_001659/miR-490-5p/PIK3CA regulatory axis.CONCLUSION Knockdown of lncRNA XLOC_001659 inhibits proliferation and invasion of ESCC cells via regulation of miR-490-5p/PIK3CA,suggesting that it may play a role in ESCC tumorigenesis and progression.
基金grants from the National Natural Science Foundation of China(Project No.40306001) the Foundation for the Author of National Excellent Doctoral Dissertation of P.R.China(Grant No.200354)from Ministry of Education of China and Chinese Academy of Sciences.It was partially support by BSRF(Project No.SR-03097).
文摘Synchrotron radiation X-ray fluorescence （SR-XRF） approach was applied to analyzing of Chinstrap penguin （ Pygoscelis Antarctica） cortical bone. The method enabled the in situ determination of Ca and P concentrations and the Ca/P ratio in cortical bone. The preliminary results show that ： （ 1 ） there is the bone site-related difference for Ca and P concentrations. The mean values for the investigated parameters （ on a dry-weight basis） are： 30.7% （Ca） and 14.9% （P） for the femoral cortical bone, 21.4% （Ca） and 11.5% （P） for wing cortical bone. （2） The variation for the Ca/P ratio in cortical bone is lower than those for Ca and P separately. This is in agreement with the previous report that the specificity of the Ca/P ratio is better than that of Ca and P concentrations and is more reliable for the diagnosis of bone disorders. The authors suggest that further studies be conducted to establish norreal values of Ca, P and Ca/P ratio for polar animals and provide a basis for the diagnosis of bone disorders.
基金supported by the National Key R&D Program of China (2016YFC0500706)
文摘Desert plants take on unique physiologically adaptive mechanisms in response to an adverse environment. In this study, we determined the concentrations of leaf nitrogen(N), phosphorus(P), and calcium(Ca) fraction for dominant species of Artemisia ordosica, A. frigida, Calligonum mongolicum, and Oxytropis aciphylla in the Alxa Desert and discussed seasonal changes of their leaf N:P ratio and Ca fraction. The results showed that, from May to September, the N:P ratios of A. ordosica and C. mongolicum gradually and significantly increased, while those of A. frigida, and O. aciphylla had an increase trend that was not significant; the physiologically active Ca of A. ordosica and A. frigida increased significantly,while that of C. mongolicum and O. aciphylla decreased significantly. The physiologically inert calcium of C. mongolicum increased extremely significantly, while that of others was not significant. There was a significantly positive correlation between the N:P ratio and physiologically active Ca for A. ordosica, and the N:P ratio was significantly and negatively correlated with physiologically active Ca for O. aciphylla. These findings revealed that the physiological regulation mechanism was different for the plants either in earlier stage or later stage of plant-community succession.
文摘An experiment on the phosphorus requirement and the proper Ca/P ratio in the diet of the black sea bream using the phosphorus gradient method (with casein as basic diet, sodium dihydrogen phosphate as source of phosphorus, and calcium lactate as source of calcium) showed that growth was greatly affected by the diet’s phosphorus content and Ca/P ratio. Inadequate phosphorus in the diet resulted in slow growth and poor food conversion ratio (FCR). Analyses of the fish body showed it contained a high level of lipid but a low level of moisture, ash, calcium and phosphorus. The optimal values of phosphorus and Ca/P ratio in the black sea bream diet are 0.68% and 1:2 respectively. Phosphorus in excess of this optimum value resulted in slow growth or even death. The results of this experiment clearly indicated that phosphorus is the principal mineral additive affecting black sea bream growth.
