AIM: To establish a convenient immunoassay method based on recombinant antigen preS1(21-119aa) to detect anti-preS1 antibodies and evaluate the clinical significance of antibodies in hepatitis B. METHODS: The expressi...AIM: To establish a convenient immunoassay method based on recombinant antigen preS1(21-119aa) to detect anti-preS1 antibodies and evaluate the clinical significance of antibodies in hepatitis B. METHODS: The expression plasmid pET-28a-preS1 was constructed, and a large quantity of preS1(21-119aa) fragment of the large HBsAg protein was obtained. The preS1 fragment purified by Ni(2+)-IDA affinity chromatography was used as coated antigen to establish the indirect ELISA based on streptavidin-biotin system for detection of the anti-preS1 antibodies in sera from HBV-infected patients. For follow-up study, serial sera were collected during the clinical course of 21 HBV-infected patients and anti-preS1 antibodies, preS1 antigen, HBV-DNA and other serological HBV markers were analyzed. RESULTS: preS1(21-119aa) fragment was highly expressed from the plasmid pET-28a-preS1 in a soluble form in E.Coli (30mg.L(-1)), and easily purified to high purity over 90% by one step of Ni(2+)-IDA-sepharose 6B affinity chromatography. The purity and antigenicity of the purified preS1(21-119aa) protein was determined by 150g.L(-1) SDS-PAGE, Western blot and a direct ELISA. Recombinant preS1(21-119aa) protein was successfully applied in the immunoassay which could sensitively detect the anti-preS1 antibodies in serum specimens of acute or chronic hepatitis B patients. Results showed that more than half of 19 acute hepatitis B patients produced anti-preS1 antibodies during recovery of the disease, however, the response was only found in a few of chronic patients. In the clinical follow-up study of 11 patients with anti-preS1 positive serological profile, HBsAg and HBV-DNA clearance occurred in 6 of 10 acute hepatitis B patients in 5-6 months, and seroconversion of HBeAg and disappearance of HBV-DNA occurred in 1 chronic patients treated with lavumidine, a antiviral agent. CONCLUSION: The high-purity preS1(21-119aa) coated antigen was successfully prepared by gene expression and affinity chromatography. Using this antigen, a conveniently de展开更多
In actual physiological environments,bacteria can activate the immune system and release lactic acid.However,the detailed contribution of lactic acid to the passivation behavior of titanium(Ti)alloys is still unclear....In actual physiological environments,bacteria can activate the immune system and release lactic acid.However,the detailed contribution of lactic acid to the passivation behavior of titanium(Ti)alloys is still unclear.The current work investigated the in vitro passivation behavior of Ti-6Al-4V(TC4)alloys fabricated by laser powder bed fusion in Hank's solution with and without adding lactic acid.Electrochemical methods,inductively coupled plasma atomic emission spectrometer,and X-ray photoelectron spectroscopy were jointly used.Adding lactic acid decreases the corrosion resistance of samples by degrading the formed passive film.The film formed in the(lactic acid)-containing solution exhibits a higher level of oxygen vacancies and a lower thickness,attributed to the suppressed formation of Ti^(4+)transformed from Ti^(3+)and Ti^(2+).Moreover,the presence of lactic acid would increase the open circuit potential,relieve the ions release,and hinder the deposition of calcium phosphates within 24 h immersion.展开更多
The thermal decomposition kinetics of dehydroabietic acid in static state air was investigated by TG/DTA/DSC techniques with various heating rates of 5,10,15 and 20 K·min-1.TG/DTA curves showed that decomposition...The thermal decomposition kinetics of dehydroabietic acid in static state air was investigated by TG/DTA/DSC techniques with various heating rates of 5,10,15 and 20 K·min-1.TG/DTA curves showed that decomposition proceeded through a well-defined step in air.The melting point,molar enthalpy and entropy of fusion of dehydroabietic acid were determined as 445.05 K,19.74 kJ·mol-1 and 44.35 J·mol-1·K-1,by differential scanning calorimetry(DSC).The non-isothermal kinetics parameters were analyzed by means of the Kissinger and Flynn-Wall-Ozawa methods,and the thermal decomposition mechanism of dehydroabietic acid was also studied with the Satava-Sestak method.The results showed that the thermal decomposition mechanism of dehydroabietic acid in air was controlled by interface reaction R3,and the apparent activation energy and pre-exponential factor were 107.89 kJ·mol-1 and 9.33×108 s-1,respectively.展开更多
基金the grants No.KY951-Al-301 and No.KY95T-06-03 from the 9th Five Years Plan Key Research Programs of the Chinese Academy of Sciences.
文摘AIM: To establish a convenient immunoassay method based on recombinant antigen preS1(21-119aa) to detect anti-preS1 antibodies and evaluate the clinical significance of antibodies in hepatitis B. METHODS: The expression plasmid pET-28a-preS1 was constructed, and a large quantity of preS1(21-119aa) fragment of the large HBsAg protein was obtained. The preS1 fragment purified by Ni(2+)-IDA affinity chromatography was used as coated antigen to establish the indirect ELISA based on streptavidin-biotin system for detection of the anti-preS1 antibodies in sera from HBV-infected patients. For follow-up study, serial sera were collected during the clinical course of 21 HBV-infected patients and anti-preS1 antibodies, preS1 antigen, HBV-DNA and other serological HBV markers were analyzed. RESULTS: preS1(21-119aa) fragment was highly expressed from the plasmid pET-28a-preS1 in a soluble form in E.Coli (30mg.L(-1)), and easily purified to high purity over 90% by one step of Ni(2+)-IDA-sepharose 6B affinity chromatography. The purity and antigenicity of the purified preS1(21-119aa) protein was determined by 150g.L(-1) SDS-PAGE, Western blot and a direct ELISA. Recombinant preS1(21-119aa) protein was successfully applied in the immunoassay which could sensitively detect the anti-preS1 antibodies in serum specimens of acute or chronic hepatitis B patients. Results showed that more than half of 19 acute hepatitis B patients produced anti-preS1 antibodies during recovery of the disease, however, the response was only found in a few of chronic patients. In the clinical follow-up study of 11 patients with anti-preS1 positive serological profile, HBsAg and HBV-DNA clearance occurred in 6 of 10 acute hepatitis B patients in 5-6 months, and seroconversion of HBeAg and disappearance of HBV-DNA occurred in 1 chronic patients treated with lavumidine, a antiviral agent. CONCLUSION: The high-purity preS1(21-119aa) coated antigen was successfully prepared by gene expression and affinity chromatography. Using this antigen, a conveniently de
基金The authors acknowledge the Fundamental Research Program of Jiangsu Province(BK20201000)the Australian Research Council through the Discovery Project(DP110101653,DP130103592)+1 种基金the Basic and Applied Basic Research Foundation of Guangdong Province,China(2022A1515140123,2021A1515110729)the Foshan(Southern China)Institute for New Materials(2021AYF25017).The authors are grateful to Jinling Zhu.
文摘In actual physiological environments,bacteria can activate the immune system and release lactic acid.However,the detailed contribution of lactic acid to the passivation behavior of titanium(Ti)alloys is still unclear.The current work investigated the in vitro passivation behavior of Ti-6Al-4V(TC4)alloys fabricated by laser powder bed fusion in Hank's solution with and without adding lactic acid.Electrochemical methods,inductively coupled plasma atomic emission spectrometer,and X-ray photoelectron spectroscopy were jointly used.Adding lactic acid decreases the corrosion resistance of samples by degrading the formed passive film.The film formed in the(lactic acid)-containing solution exhibits a higher level of oxygen vacancies and a lower thickness,attributed to the suppressed formation of Ti^(4+)transformed from Ti^(3+)and Ti^(2+).Moreover,the presence of lactic acid would increase the open circuit potential,relieve the ions release,and hinder the deposition of calcium phosphates within 24 h immersion.
文摘The thermal decomposition kinetics of dehydroabietic acid in static state air was investigated by TG/DTA/DSC techniques with various heating rates of 5,10,15 and 20 K·min-1.TG/DTA curves showed that decomposition proceeded through a well-defined step in air.The melting point,molar enthalpy and entropy of fusion of dehydroabietic acid were determined as 445.05 K,19.74 kJ·mol-1 and 44.35 J·mol-1·K-1,by differential scanning calorimetry(DSC).The non-isothermal kinetics parameters were analyzed by means of the Kissinger and Flynn-Wall-Ozawa methods,and the thermal decomposition mechanism of dehydroabietic acid was also studied with the Satava-Sestak method.The results showed that the thermal decomposition mechanism of dehydroabietic acid in air was controlled by interface reaction R3,and the apparent activation energy and pre-exponential factor were 107.89 kJ·mol-1 and 9.33×108 s-1,respectively.
