CeCo5 alloy was prepared from the mixture of cobalt oxide （Co3O4） and cerium oxide （CeO2） powders by electro-deoxidation in molten calcium chloride. The effects of the cell voltage and sintering temperature on the...CeCo5 alloy was prepared from the mixture of cobalt oxide （Co3O4） and cerium oxide （CeO2） powders by electro-deoxidation in molten calcium chloride. The effects of the cell voltage and sintering temperature on the electrolysis process were reported. The electro-deoxidation mechanism was investigated by potentiodynamic polarization using a molybdenum cavity electrode in conjunction with characterization of the products from constant voltage electrolysis under different conditions by XRD and SEM. The electrochemical property of CeCo5 alloy was investigated by cyclic voltammetry measurements. The results show that the electro-deoxidation rate increases with increasing the cell voltage and decreasing the sintering temperature. The pure CeCo5 can be prepared by direct electro-deoxidation of mixed CeO2/Co3O4 pellets sintered at 850 °C when the cell voltage of 3.1 V is applied. The electro-deoxidation proceeds by the simultaneous reduction of Co3O4 to Co and reduction of CeO2 to CeOCl, followed by CeOCl reduction on the pre-formed Co to form CeCo5 alloy which shows a good cycling stability.展开更多
Hexagonal single-crystalline cerium carbonate hydroxide （CeCO3OH） precursors with dendrite morphologies have been synthesized by a facile hydrothermal method at 180 C using CeCl3-7H2O as the cerium source, triethyle...Hexagonal single-crystalline cerium carbonate hydroxide （CeCO3OH） precursors with dendrite morphologies have been synthesized by a facile hydrothermal method at 180 C using CeCl3-7H2O as the cerium source, triethylenetetramine as both an alkaline and carbon source, with triethylenete- tramine also playing an important role in the formation of the dendrite structure. Polycrystalline ceria （CeO2） have been obtained by calcining the precursor at 500 C for 4 h. Tile morphology of the precursor was partly maintained during the heating process. The optical absorption spectra indicate the CeO2 nano/microstructures have a direct band gap of 2.92 eV, which is lower than values of the bulk powder due to the quantum size effect. The high absorption in the UV region for CeO2 nano/microstructure indicated that this material was expected to be used as UV-blocking materials.展开更多
AIM:To study the epidemiologic indicators of uptake and characteristic colonoscopic findings in the Croatian National Colorectal Cancer Screening Program.METHODS:Colorectal cancer(CRC) was the second leading cause of ...AIM:To study the epidemiologic indicators of uptake and characteristic colonoscopic findings in the Croatian National Colorectal Cancer Screening Program.METHODS:Colorectal cancer(CRC) was the second leading cause of cancer mortality in men(n = 1063,49.77/100 000),as well as women(n = 803,34.89/100 000) in Croatia in 2009.The Croatian National CRC Screening Program was established by the Ministry of Health and Social Welfare,and its implementation started in September,2007.The coordinators were recruited in each county institute of public health with an obligation to provide fecal occult blood testing(FOBT) to the participants,followed by colonoscopy in all positive cases.The FOBT was performed by hypersensitive guaiac-based Hemognost card test(Biognost,Zagreb).The test and short questionnaire were delivered to the home addresses of all citizens aged 50-74 years consecutively during a 3-year period.Each participant was required to complete the questionnaire and send it together with the stool specimen on three test cards back to the institute for further analysis.About 4% FOBT positive cases are expected in normal risk populations.A descriptive analysis was performed.RESULTS:A total of 1 056 694 individuals(born between 1933-1945 and 1952-1957) were invited to screening by the end of September 2011.In total,210 239(19.9%) persons returned the envelope with a completed questionnaire,and 181 102 of them returned it with a correctly placed stool specimen on FOBT cards.Until now,12 477(6.9%),FOBT-positive patients have been found,which is at the upper limit of the expected values in European Guidelines for Quality Assurance in CRC Screening and Diagnosis [European Union(EU) Guidelines].Colonoscopy was performed in 8541 cases(uptake 66%).Screening has identified CRC in 472 patients(5.5% of colonoscopied,3.8% of FOBT-positive,and 0.26% of all screened individuals).This is also in the expected range according to EU Guidelines.Polyps were found and removed in 3329(39% of colonoscopied) patients.The largest number of polyps were found in the left half of the colon:64%(19%,37% and 8% in the rectum,sigma,and descendens,respectively).The other 36% were detected in the proximal part(17% in the transverse colon and 19% in ceco-ascending colon).Small polyps in the rectum(5-10 mm in diameter),sigmoid and descending colon were histologically found to be tubular adenomas in 60% of cases,with a low degree of dysplasia,and 40% were classified as hyperplastic.Polyps of this size in the transverse or ceco-ascending colon in almost 20% had a histologically villous component,but still had a low degree of dysplasia.Polyps sized 10-20 mm in diameter were in 43% cases tubulovillous,and among them,32% had areas with a high degree of dysplasia,especially those polyps in the cecoascending or transverse part.The characteristics of the Croatian CRC Screening National Program in the first 3 years were as follows:relatively low percentage of returned FOBT,higher number of FOBT-positive persons but still in the range for population-based programs,and higher number of pathologic findings(polyps and cancers).CONCLUSION:These results suggest a need for intervention strategies that include organizational changes and educational activities to improve awareness of CRC screening usefulness and increase participation rates.展开更多
基金Project (E2010000941) supported by Hebei Provincial Natural Science Foundation of ChinaProject (11212119D) supported by Hebei Provincial Science and Technology Support Program of China
文摘CeCo5 alloy was prepared from the mixture of cobalt oxide （Co3O4） and cerium oxide （CeO2） powders by electro-deoxidation in molten calcium chloride. The effects of the cell voltage and sintering temperature on the electrolysis process were reported. The electro-deoxidation mechanism was investigated by potentiodynamic polarization using a molybdenum cavity electrode in conjunction with characterization of the products from constant voltage electrolysis under different conditions by XRD and SEM. The electrochemical property of CeCo5 alloy was investigated by cyclic voltammetry measurements. The results show that the electro-deoxidation rate increases with increasing the cell voltage and decreasing the sintering temperature. The pure CeCo5 can be prepared by direct electro-deoxidation of mixed CeO2/Co3O4 pellets sintered at 850 °C when the cell voltage of 3.1 V is applied. The electro-deoxidation proceeds by the simultaneous reduction of Co3O4 to Co and reduction of CeO2 to CeOCl, followed by CeOCl reduction on the pre-formed Co to form CeCo5 alloy which shows a good cycling stability.
基金supported financially by the Program for Innovative Research Team in Jiangsu Province(No.SZK[2011]87)Creative and Innovative Talents Introduction Plan(No.SZT[2011]43)Special Research Foundation of Young teachers of Nanjing University of Technology(No.39701007)
文摘Hexagonal single-crystalline cerium carbonate hydroxide （CeCO3OH） precursors with dendrite morphologies have been synthesized by a facile hydrothermal method at 180 C using CeCl3-7H2O as the cerium source, triethylenetetramine as both an alkaline and carbon source, with triethylenete- tramine also playing an important role in the formation of the dendrite structure. Polycrystalline ceria （CeO2） have been obtained by calcining the precursor at 500 C for 4 h. Tile morphology of the precursor was partly maintained during the heating process. The optical absorption spectra indicate the CeO2 nano/microstructures have a direct band gap of 2.92 eV, which is lower than values of the bulk powder due to the quantum size effect. The high absorption in the UV region for CeO2 nano/microstructure indicated that this material was expected to be used as UV-blocking materials.
文摘AIM:To study the epidemiologic indicators of uptake and characteristic colonoscopic findings in the Croatian National Colorectal Cancer Screening Program.METHODS:Colorectal cancer(CRC) was the second leading cause of cancer mortality in men(n = 1063,49.77/100 000),as well as women(n = 803,34.89/100 000) in Croatia in 2009.The Croatian National CRC Screening Program was established by the Ministry of Health and Social Welfare,and its implementation started in September,2007.The coordinators were recruited in each county institute of public health with an obligation to provide fecal occult blood testing(FOBT) to the participants,followed by colonoscopy in all positive cases.The FOBT was performed by hypersensitive guaiac-based Hemognost card test(Biognost,Zagreb).The test and short questionnaire were delivered to the home addresses of all citizens aged 50-74 years consecutively during a 3-year period.Each participant was required to complete the questionnaire and send it together with the stool specimen on three test cards back to the institute for further analysis.About 4% FOBT positive cases are expected in normal risk populations.A descriptive analysis was performed.RESULTS:A total of 1 056 694 individuals(born between 1933-1945 and 1952-1957) were invited to screening by the end of September 2011.In total,210 239(19.9%) persons returned the envelope with a completed questionnaire,and 181 102 of them returned it with a correctly placed stool specimen on FOBT cards.Until now,12 477(6.9%),FOBT-positive patients have been found,which is at the upper limit of the expected values in European Guidelines for Quality Assurance in CRC Screening and Diagnosis [European Union(EU) Guidelines].Colonoscopy was performed in 8541 cases(uptake 66%).Screening has identified CRC in 472 patients(5.5% of colonoscopied,3.8% of FOBT-positive,and 0.26% of all screened individuals).This is also in the expected range according to EU Guidelines.Polyps were found and removed in 3329(39% of colonoscopied) patients.The largest number of polyps were found in the left half of the colon:64%(19%,37% and 8% in the rectum,sigma,and descendens,respectively).The other 36% were detected in the proximal part(17% in the transverse colon and 19% in ceco-ascending colon).Small polyps in the rectum(5-10 mm in diameter),sigmoid and descending colon were histologically found to be tubular adenomas in 60% of cases,with a low degree of dysplasia,and 40% were classified as hyperplastic.Polyps of this size in the transverse or ceco-ascending colon in almost 20% had a histologically villous component,but still had a low degree of dysplasia.Polyps sized 10-20 mm in diameter were in 43% cases tubulovillous,and among them,32% had areas with a high degree of dysplasia,especially those polyps in the cecoascending or transverse part.The characteristics of the Croatian CRC Screening National Program in the first 3 years were as follows:relatively low percentage of returned FOBT,higher number of FOBT-positive persons but still in the range for population-based programs,and higher number of pathologic findings(polyps and cancers).CONCLUSION:These results suggest a need for intervention strategies that include organizational changes and educational activities to improve awareness of CRC screening usefulness and increase participation rates.
