A chemical method for removing calcium sulfate saturated solutions(0.016 mol/L CaSO_(4))using barium chloride(BaCl_(2)∙2H_(2)O)and sodium phosphate(Na_(3)PO_(4))was experimentally studied.The main interest is to remov...A chemical method for removing calcium sulfate saturated solutions(0.016 mol/L CaSO_(4))using barium chloride(BaCl_(2)∙2H_(2)O)and sodium phosphate(Na_(3)PO_(4))was experimentally studied.The main interest is to remove these ions from the solution through the precipitation of two solid species:sulfate(SO_(4)^(2−))as barite(BaSO4),and calcium(Ca^(2+))as hydroxyapatite(Ca_(5)(PO_(4))_(3)OH).Additionally,a solid/liquid separation method(i.e.,flotation)was explored,using oleic acid and dodecylamine as collectors.The results show that,the chemical treatment of saturated solutions at 60℃,pH 11.5 and using 3.9 g/L BaCl_(2)·2H_(2)O and 1.6 g/L Na_(3)PO_(4),promotes the precipitation of barium sulfate and calcium-deficient hydroxyapatite(Ca_(10−x)(HPO_(4))_(x)(PO_(4))_(6−x)(OH)_(2−x)),with residual concentrations of calcium and sulfate below 0.10 and 5 mg/L,respectively.The residual calcium concentration increases to 28 mg/L when using the same amount of reactants,at temperature and pH values below those quoted.The highest flotation recovery of hydroxyapatite with oleic acid at pH 9.5 was about 80%,while that of barite floated with dodecylamine at pH 6.5 was about 90%.展开更多
The reaction of the alkyl alkylidyne W（CH2CMe3）3（=CSiMe3） （1） with H20 in THF and with D20 in benzene-d6 gave two new trimeric oxo complexes： W3O3（μ=O）3（CH2CMe3）6（THF）3 （2） and [W303（μ=O）3（Ch2CMe3...The reaction of the alkyl alkylidyne W（CH2CMe3）3（=CSiMe3） （1） with H20 in THF and with D20 in benzene-d6 gave two new trimeric oxo complexes： W3O3（μ=O）3（CH2CMe3）6（THF）3 （2） and [W303（μ=O）3（Ch2CMe3）6（D2O）3] 2benzene-d6 （3.2benzened6）, respectively, each containing two alkyl ligands per W atom. This is in contrast to the dimer W2o（β-O）（CH2CMe3）6, containing three alkyl ligands per W atom, from the previously reported reaction of the alkyl alkylidyne analog W（CH2CMe3）3- （=-CCMe3） with H2O. In the reaction of 1 with D20 in THF, an unstable intermediate W2O2（μ-O）（CD2SiMe3）2（CH2CMe3）4 （4-d4） was identified. Kinetic studies of the reactions of 1 with excess H2O and D2O in THF-ds, yielding 4 and 4-d4, respectively, give a kinetic isotope effect （KIE） of 3.46（3） at 298（1） K, suggesting that the disappearance of 1 is a rate-determining step.展开更多
To characterize the antigenicity of nucleocapsid proteins(NP) derived from canine coronavirus(CCo V) and canine respiratory coronavirus(CRCo V) in China, the N genes of CCo V(CCo V-BJ70) and CRCo V(CRCo V-BJ202) were ...To characterize the antigenicity of nucleocapsid proteins(NP) derived from canine coronavirus(CCo V) and canine respiratory coronavirus(CRCo V) in China, the N genes of CCo V(CCo V-BJ70) and CRCo V(CRCo V-BJ202) were cloned from swabs obtained from diseased pet dogs in Beijing and then sequenced. The recombinant NPs(r NPs) were expressed in Escherichia coli and purified by nickel-affinity column and size exclusion chromatography. Sequencing data indicated that the N genes of CCo V-BJ70 and CRCo V-BJ202 belonging to two distinctly different groups were relatively conserved within each subgroup. Sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE) results showed that r NPs of CCo V and CRCo V were expressed efficiently and isolated with a final purity of over 95%. Western blot analysis revealed the r NP from CRCo V could cross-react with mice antisera against human coronavirus(HCo V-229 E, NL63, OC43, HKU1), while r NP of CCo V had cross-reactivity with only anti-sera against viruses belonging to the same group(HCo V-229 E and NL63). In summary, CCo V and CRCo V r NPs were successfully expressed in E. coli and showed antigenic cross-reactivity with antisera raised against human coronaviruses. These findings indicate that further serologic studies on coronavirus infections at the animal-human interface are needed.展开更多
基金the personnel of Cinvestav-IPN Unidad Saltillo as well as the scholarships awarded by CONACYT(México).
文摘A chemical method for removing calcium sulfate saturated solutions(0.016 mol/L CaSO_(4))using barium chloride(BaCl_(2)∙2H_(2)O)and sodium phosphate(Na_(3)PO_(4))was experimentally studied.The main interest is to remove these ions from the solution through the precipitation of two solid species:sulfate(SO_(4)^(2−))as barite(BaSO4),and calcium(Ca^(2+))as hydroxyapatite(Ca_(5)(PO_(4))_(3)OH).Additionally,a solid/liquid separation method(i.e.,flotation)was explored,using oleic acid and dodecylamine as collectors.The results show that,the chemical treatment of saturated solutions at 60℃,pH 11.5 and using 3.9 g/L BaCl_(2)·2H_(2)O and 1.6 g/L Na_(3)PO_(4),promotes the precipitation of barium sulfate and calcium-deficient hydroxyapatite(Ca_(10−x)(HPO_(4))_(x)(PO_(4))_(6−x)(OH)_(2−x)),with residual concentrations of calcium and sulfate below 0.10 and 5 mg/L,respectively.The residual calcium concentration increases to 28 mg/L when using the same amount of reactants,at temperature and pH values below those quoted.The highest flotation recovery of hydroxyapatite with oleic acid at pH 9.5 was about 80%,while that of barite floated with dodecylamine at pH 6.5 was about 90%.
基金supported by the US National Science Foundation(CHE-0749651 & CHE-1012173)
文摘The reaction of the alkyl alkylidyne W（CH2CMe3）3（=CSiMe3） （1） with H20 in THF and with D20 in benzene-d6 gave two new trimeric oxo complexes： W3O3（μ=O）3（CH2CMe3）6（THF）3 （2） and [W303（μ=O）3（Ch2CMe3）6（D2O）3] 2benzene-d6 （3.2benzened6）, respectively, each containing two alkyl ligands per W atom. This is in contrast to the dimer W2o（β-O）（CH2CMe3）6, containing three alkyl ligands per W atom, from the previously reported reaction of the alkyl alkylidyne analog W（CH2CMe3）3- （=-CCMe3） with H2O. In the reaction of 1 with D20 in THF, an unstable intermediate W2O2（μ-O）（CD2SiMe3）2（CH2CMe3）4 （4-d4） was identified. Kinetic studies of the reactions of 1 with excess H2O and D2O in THF-ds, yielding 4 and 4-d4, respectively, give a kinetic isotope effect （KIE） of 3.46（3） at 298（1） K, suggesting that the disappearance of 1 is a rate-determining step.
基金supported by the Mega project for Infectious Disease Research of China (2014ZX10004001-002, 2013ZX10004601)National Basic Research Program of China (2011CB504704)
文摘To characterize the antigenicity of nucleocapsid proteins(NP) derived from canine coronavirus(CCo V) and canine respiratory coronavirus(CRCo V) in China, the N genes of CCo V(CCo V-BJ70) and CRCo V(CRCo V-BJ202) were cloned from swabs obtained from diseased pet dogs in Beijing and then sequenced. The recombinant NPs(r NPs) were expressed in Escherichia coli and purified by nickel-affinity column and size exclusion chromatography. Sequencing data indicated that the N genes of CCo V-BJ70 and CRCo V-BJ202 belonging to two distinctly different groups were relatively conserved within each subgroup. Sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE) results showed that r NPs of CCo V and CRCo V were expressed efficiently and isolated with a final purity of over 95%. Western blot analysis revealed the r NP from CRCo V could cross-react with mice antisera against human coronavirus(HCo V-229 E, NL63, OC43, HKU1), while r NP of CCo V had cross-reactivity with only anti-sera against viruses belonging to the same group(HCo V-229 E and NL63). In summary, CCo V and CRCo V r NPs were successfully expressed in E. coli and showed antigenic cross-reactivity with antisera raised against human coronaviruses. These findings indicate that further serologic studies on coronavirus infections at the animal-human interface are needed.
