s: Ultrafine A2La2Ti3O10 (A=K, Na) powders with laminar structure were successfully synthesized by citric acid sol-gel method using ANO3(A=K, Na)?La(NO3)3?Ti(OBu)4 and citric acid as starting precursors. The crystalli...s: Ultrafine A2La2Ti3O10 (A=K, Na) powders with laminar structure were successfully synthesized by citric acid sol-gel method using ANO3(A=K, Na)?La(NO3)3?Ti(OBu)4 and citric acid as starting precursors. The crystalline phase of A2La2Ti3O10 can be obtained by thermal decomposition of citrate complex precursors at a relatively low temperature of 800 ℃ (600 ℃ for A=Na), about 300 ℃(500 ℃ for A=Na) lower than that of conventional solid state reaction process. The properties of the citrate precursors and the calcined powders were characterized by Infrared spectroscopy (IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), thermal-gravimetric-differential thermal analysis (TG-DTA), inductively coupled plasma (ICP) and Brunauer-Emmett-Teller (BET) techniques. Results show that the average size of A2La2Ti3O10 powders obtained by citric acid sol-gel route was reduced to 200 nm×250 nm and the specific surface area was up to 19 m2·g-1. At the same time, the product was with more regular morphological characteristics. The synthesis process and the formation of A2La2Ti3O10 were also discussed. The obtained A2La2Ti3O10 was found to be transformed from A2La2Ti3O9.5 during the formation process.展开更多
目的 为探索 L a(NO3) 3对猴头菌 H ericium erinaceum(Bull.) Pers.菌丝生长的影响及其生化机制。方法 在猴头菌菌丝发酵液中 ,加入不同浓度的 L a(NO3) 3,接种培养 7d后 ,测定菌丝生长量及菌丝生长期间胞外酶的活性。结果 0 .75～...目的 为探索 L a(NO3) 3对猴头菌 H ericium erinaceum(Bull.) Pers.菌丝生长的影响及其生化机制。方法 在猴头菌菌丝发酵液中 ,加入不同浓度的 L a(NO3) 3,接种培养 7d后 ,测定菌丝生长量及菌丝生长期间胞外酶的活性。结果 0 .75～ 1.5 m mol/L 的 L a(NO3) 3可显著提高猴头菌丝的生长 ;0 .0 0 5～ 2 .0 mm ol/L 的 L a(NO3) 3可提高猴头菌丝生长期间胞外蛋白酶、纤维素酶、淀粉酶的活性及蛋白质的含量 ,且当 L a(NO3) 3浓度为 1.0 mm ol/L、0 .75 m mol/L时 ,这 3种酶的活性及蛋白质含量分别达到最高。结论 0 .75～ 1.5 m mol/L的 L a(NO3) 3促进菌丝分泌胞外蛋白 ,从而提高了猴头菌丝胞外蛋白酶、纤维素酶、淀粉酶的活性 ,酶活性的提高又促进菌丝的生长。因此 ,在培养猴头菌丝时 ,可在培养液中加入 0 .75～ 1.5 mm ol/L的 L a(NO3)展开更多
AIM: To compare the gene expression between La(NO3)3-exposed and control rats in vivo. METHODS: Rats were fed La(NO3)3 once daily at a dose of 20 mg/kg for one month by gavage. Gene expression of hepatocytes was detec...AIM: To compare the gene expression between La(NO3)3-exposed and control rats in vivo. METHODS: Rats were fed La(NO3)3 once daily at a dose of 20 mg/kg for one month by gavage. Gene expression of hepatocytes was detected using mRNA differential display (DD) technique and cDNA microarray and compared between treated and control groups. RESULTS: Six differentially expressed sequence tags were cloned by DD, of which five were up regulated and one was down regulated in treated rats. Two sequences were determined. One band was novel. The other shared 100% sequence homology with AU080263 Sugano mouse brain mncb Mus musculus cDNA clone MNCb-5435 5'. With DNA microarray, 136 differentially expressed genes were identified including 131 over-expressed genes and 5 under-expressed genes. Most of these differentially expressed genes were cell signal and transmission genes, genes associated with metabolism, protein translation and synthesis. CONCLUSION: La(NO3)3 could change the expression levels of some kinds of genes. Further analysis of the differentially expressed genes would be helpful for understanding the wide biological effect spectrum of rare earth elements.展开更多
文摘s: Ultrafine A2La2Ti3O10 (A=K, Na) powders with laminar structure were successfully synthesized by citric acid sol-gel method using ANO3(A=K, Na)?La(NO3)3?Ti(OBu)4 and citric acid as starting precursors. The crystalline phase of A2La2Ti3O10 can be obtained by thermal decomposition of citrate complex precursors at a relatively low temperature of 800 ℃ (600 ℃ for A=Na), about 300 ℃(500 ℃ for A=Na) lower than that of conventional solid state reaction process. The properties of the citrate precursors and the calcined powders were characterized by Infrared spectroscopy (IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), thermal-gravimetric-differential thermal analysis (TG-DTA), inductively coupled plasma (ICP) and Brunauer-Emmett-Teller (BET) techniques. Results show that the average size of A2La2Ti3O10 powders obtained by citric acid sol-gel route was reduced to 200 nm×250 nm and the specific surface area was up to 19 m2·g-1. At the same time, the product was with more regular morphological characteristics. The synthesis process and the formation of A2La2Ti3O10 were also discussed. The obtained A2La2Ti3O10 was found to be transformed from A2La2Ti3O9.5 during the formation process.
文摘目的 为探索 L a(NO3) 3对猴头菌 H ericium erinaceum(Bull.) Pers.菌丝生长的影响及其生化机制。方法 在猴头菌菌丝发酵液中 ,加入不同浓度的 L a(NO3) 3,接种培养 7d后 ,测定菌丝生长量及菌丝生长期间胞外酶的活性。结果 0 .75～ 1.5 m mol/L 的 L a(NO3) 3可显著提高猴头菌丝的生长 ;0 .0 0 5～ 2 .0 mm ol/L 的 L a(NO3) 3可提高猴头菌丝生长期间胞外蛋白酶、纤维素酶、淀粉酶的活性及蛋白质的含量 ,且当 L a(NO3) 3浓度为 1.0 mm ol/L、0 .75 m mol/L时 ,这 3种酶的活性及蛋白质含量分别达到最高。结论 0 .75～ 1.5 m mol/L的 L a(NO3) 3促进菌丝分泌胞外蛋白 ,从而提高了猴头菌丝胞外蛋白酶、纤维素酶、淀粉酶的活性 ,酶活性的提高又促进菌丝的生长。因此 ,在培养猴头菌丝时 ,可在培养液中加入 0 .75～ 1.5 mm ol/L的 L a(NO3)
基金Supported by grant of Key Project of National Natural ScienceFoundation of China,No.29890280-3
文摘AIM: To compare the gene expression between La(NO3)3-exposed and control rats in vivo. METHODS: Rats were fed La(NO3)3 once daily at a dose of 20 mg/kg for one month by gavage. Gene expression of hepatocytes was detected using mRNA differential display (DD) technique and cDNA microarray and compared between treated and control groups. RESULTS: Six differentially expressed sequence tags were cloned by DD, of which five were up regulated and one was down regulated in treated rats. Two sequences were determined. One band was novel. The other shared 100% sequence homology with AU080263 Sugano mouse brain mncb Mus musculus cDNA clone MNCb-5435 5'. With DNA microarray, 136 differentially expressed genes were identified including 131 over-expressed genes and 5 under-expressed genes. Most of these differentially expressed genes were cell signal and transmission genes, genes associated with metabolism, protein translation and synthesis. CONCLUSION: La(NO3)3 could change the expression levels of some kinds of genes. Further analysis of the differentially expressed genes would be helpful for understanding the wide biological effect spectrum of rare earth elements.
