Objective The causal agent for SARS is considered as a novel coronavirus that has never been described both in human and animals previously. The stability of SARS coronavirus in human specimens and in environments was...Objective The causal agent for SARS is considered as a novel coronavirus that has never been described both in human and animals previously. The stability of SARS coronavirus in human specimens and in environments was studied. Methods Using a SARS coronavirus strain CoV-P9, which was isolated from pharyngeal swab of a probable SARS case in Beijing, its stability in mimic human specimens and in mimic environment including surfaces of commonly used materials or in household conditions, as well as its resistances to temperature and UV irradiation were analyzed. A total of 106 TCID50 viruses were placed in each tested condition, and changes of the viral infectivity in samples after treatments were measured by evaluating cytopathic effect (CPE) in cell line Vero-E6 at 48 h after infectionn. Results The results showed that SARS coronavirus in the testing condition could survive in serum, 1:20 diluted sputum and feces for at least 96 h, whereas it could remain alive in urine for at least 72 h with a low level of infectivity. The survival abilities on the surfaces of eight different materials and in water were quite comparable, revealing reduction of infectivity after 72 to 96 h exposure. Viruses stayed stable at 4℃, at room temperature (20℃) and at 37℃ for at least 2 h without remarkable change in the infectious ability in cells, but were converted to be non-infectious after 90-, 60- and 30-min exposure at 56℃, at 67℃ and at 75℃, respectively. Irradiation of UV for 60 min on the virus in culture medium resulted in the destruction of viral infectivity at an undetectable level. Conclusion The survival ability of SARS coronavirus in human specimens and in environments seems to be relatively strong. Heating and UV irradiation can efficiently eliminate the viral infectivity.展开更多
The spatial distribution of acoustic emission （AE） events in the failure process of several rock specimens was acquired using an advanced AE acquiring and analyzing system. The box counting method （BCM） was employ...The spatial distribution of acoustic emission （AE） events in the failure process of several rock specimens was acquired using an advanced AE acquiring and analyzing system. The box counting method （BCM） was employed to calculate the fractal dimension （FD） of AE spatial distribution. There is a similar correlation between the fractal dimension and the load strength for different rock specimens. The fractal dimension presents a decreasing trend with the increase of load strength. For the same kind of specimens, their FD values will decrease to the level below a relatively same value when they reach failure. This value can be regarded as the critical value, which implies that the specimen will reach failure soon. The results reflect that it is possible to correlate the damage of rock with a macroscopic parameter, the FD value of AE signals. Furthermore, the FD value can be also used to forecast the final failure of rock. This conclusion allows identifying or predicting the damage in rock with a great advantage over the classic theory and is very crucial for forecasting rockburst or other dynamic disasters in mines.展开更多
Objective LcrV is an important component for the development of a subunit vaccine against plague.To reduce immunosuppressive activity of LcrV,a recombinant LcrV variant lacking amino acids 271 to 326 （rV270） was pre...Objective LcrV is an important component for the development of a subunit vaccine against plague.To reduce immunosuppressive activity of LcrV,a recombinant LcrV variant lacking amino acids 271 to 326 （rV270） was prepared by different methods in this study.Methods A new strategy that produced non-tagged or authentic rV270 protein was designed by insertion of rV270-thrombin-hexahistidine fusion gene into the vector pET24a,or by insertion of hexahistidine-enterokinase-rV270 or hexahistitine-factor Xa-rV270 fusion gene into the vector pET32a.After Co2＋ affinity chromatography,a purification strategy was developed by cleavage of His tag on column,following Sephacryl S-200HR column filtration chromatography.Results Removal of His tag by thrombin,enterokinase and factor Xa displayed a yield of 99.5%,32.4% and 15.3%,respectively.Following Sephacryl S-200HR column filtration chromatography,above 97% purity of rV270 protein was obtained.Purified rV270 that was adsorbed to 25% （v/v） Al（OH）3 adjuvant in phosphate-buffered saline （PBS） induced very high titers of antibody to rV270 in BALB/c mice and protected them （100% survival） against subcutaneous challenge with 106 CFU of Y.pestis virulent strain 141.Conclusion The completely authentic rV270 protein can be prepared by using enterokinase or factor Xa,but they exhibited extremely low cleavage activity to the corresponding recognition site.Thrombin cleavage is an efficient strategy to prepare non-tagged rV270 protein and can be easily operated in a large scale due to its relatively low cost and high cleavage efficacy.The recombinant rV270 can be used as a key component to develop a subunit vaccine of plague.展开更多
To the Editor:In December 2019,coronavirus disease 2019 outbreak caused by the 2019 novel coronavirus(2019-nCoV)happened in Wuhan,China.Now,it has posed a worldwide public health threat.Real-time quanti-tative polymer...To the Editor:In December 2019,coronavirus disease 2019 outbreak caused by the 2019 novel coronavirus(2019-nCoV)happened in Wuhan,China.Now,it has posed a worldwide public health threat.Real-time quanti-tative polymerase chain reaction(RT-qPCR)was recom-mended as an effective pathogen detection method and has played an important role in prevention and control of the current outbreak.Many research institutions have released their primer sets for RT-qPCR.If the variant sites were located in the primer regions,the efficiency of RT-qPCR would be reduced,thus possibly causing false negative results,and leading to unpredictable impact on the diagnosis of patients and the control of this outbreak.Therefore,a comprehensive investigation on 2019-nCoV genome variation is necessary to evaluate the effectiveness of current released RT-qPCR methods.展开更多
With time and space resolved technique, we have recorded time resolved spectra of irradiation of the plasma induced by Nd: YAG laser ablating metal Aluminum in Ar, in which, laser pulse energy was set up to 145 mJ/pul...With time and space resolved technique, we have recorded time resolved spectra of irradiation of the plasma induced by Nd: YAG laser ablating metal Aluminum in Ar, in which, laser pulse energy was set up to 145 mJ/pulse and the buffer pressure 100 kpa. The continuum radiation and special emission of Aluminum plasma were studied based on the records. According to time distribution of Al Ⅰ396.15 nm emission, we analyzed the time differences between characteristic and continuum radiation evolving. We tried to explain the time phases of characteristic radiation evolving with traditional theoretical model of atomic transition. As the result, we found that it was difficult to explain our experimental results with the model. In order to explain our experimental results, we need new model or to improve the traditional theoretical model of atomic transition.展开更多
Congenital rubella syndrome is characterized by the triad of deafness, cataract and cardiovascular mafformations. The great majority of the cases in the literature have been usually diagnosed in infancy and childhood ...Congenital rubella syndrome is characterized by the triad of deafness, cataract and cardiovascular mafformations. The great majority of the cases in the literature have been usually diagnosed in infancy and childhood because of various defects at birth. However, we report a rare case of suspected congenital rubella syndrome in an adult with unilateral pulmonary artery stenosis and late-onset cataract.展开更多
One hundred andfifty-three isolates from the environment and 36 reference strains of the Legionella were studied with regards to their composition of cellular fatty acids as determined by gas chromatography,and then we...One hundred andfifty-three isolates from the environment and 36 reference strains of the Legionella were studied with regards to their composition of cellular fatty acids as determined by gas chromatography,and then were classified into 41 groups by numerical analysis.Most reference strains formed only a single group,except L.micdadei,L.jamestowniensis,L.parisiensis,L.jorda-nis,L.feeleii and L.longbeachae,which were clustered into two or three groups.Even serological types of L.pneumophila could be clearly identified.Therefore,in this study,numerical analysis of cellular fatty acid composition is an effective method for identifying Legionella species.展开更多
基金This work was supported by the National High-Technology Research and Development Program of China (863 Program) 2003AA208402.
文摘Objective The causal agent for SARS is considered as a novel coronavirus that has never been described both in human and animals previously. The stability of SARS coronavirus in human specimens and in environments was studied. Methods Using a SARS coronavirus strain CoV-P9, which was isolated from pharyngeal swab of a probable SARS case in Beijing, its stability in mimic human specimens and in mimic environment including surfaces of commonly used materials or in household conditions, as well as its resistances to temperature and UV irradiation were analyzed. A total of 106 TCID50 viruses were placed in each tested condition, and changes of the viral infectivity in samples after treatments were measured by evaluating cytopathic effect (CPE) in cell line Vero-E6 at 48 h after infectionn. Results The results showed that SARS coronavirus in the testing condition could survive in serum, 1:20 diluted sputum and feces for at least 96 h, whereas it could remain alive in urine for at least 72 h with a low level of infectivity. The survival abilities on the surfaces of eight different materials and in water were quite comparable, revealing reduction of infectivity after 72 to 96 h exposure. Viruses stayed stable at 4℃, at room temperature (20℃) and at 37℃ for at least 2 h without remarkable change in the infectious ability in cells, but were converted to be non-infectious after 90-, 60- and 30-min exposure at 56℃, at 67℃ and at 75℃, respectively. Irradiation of UV for 60 min on the virus in culture medium resulted in the destruction of viral infectivity at an undetectable level. Conclusion The survival ability of SARS coronavirus in human specimens and in environments seems to be relatively strong. Heating and UV irradiation can efficiently eliminate the viral infectivity.
基金supported by the Special Subject of the National High-Tech Research and Development Program of China (No.2007AA06Z107)Supporting Project of New Century Excellence Talents in Chinese Universities (No.NCET-07-0163)+1 种基金Opening Research Foundation of CAS Key Laboratory of Rock and Soil Mechanics (No.Z110607)Youth Foundation of Henan Polytechnic University (No.Q2008-51)
文摘The spatial distribution of acoustic emission （AE） events in the failure process of several rock specimens was acquired using an advanced AE acquiring and analyzing system. The box counting method （BCM） was employed to calculate the fractal dimension （FD） of AE spatial distribution. There is a similar correlation between the fractal dimension and the load strength for different rock specimens. The fractal dimension presents a decreasing trend with the increase of load strength. For the same kind of specimens, their FD values will decrease to the level below a relatively same value when they reach failure. This value can be regarded as the critical value, which implies that the specimen will reach failure soon. The results reflect that it is possible to correlate the damage of rock with a macroscopic parameter, the FD value of AE signals. Furthermore, the FD value can be also used to forecast the final failure of rock. This conclusion allows identifying or predicting the damage in rock with a great advantage over the classic theory and is very crucial for forecasting rockburst or other dynamic disasters in mines.
基金supported by the National Key Program for Infectious Diseases of China (2009ZX10004-4001)
文摘Objective LcrV is an important component for the development of a subunit vaccine against plague.To reduce immunosuppressive activity of LcrV,a recombinant LcrV variant lacking amino acids 271 to 326 （rV270） was prepared by different methods in this study.Methods A new strategy that produced non-tagged or authentic rV270 protein was designed by insertion of rV270-thrombin-hexahistidine fusion gene into the vector pET24a,or by insertion of hexahistidine-enterokinase-rV270 or hexahistitine-factor Xa-rV270 fusion gene into the vector pET32a.After Co2＋ affinity chromatography,a purification strategy was developed by cleavage of His tag on column,following Sephacryl S-200HR column filtration chromatography.Results Removal of His tag by thrombin,enterokinase and factor Xa displayed a yield of 99.5%,32.4% and 15.3%,respectively.Following Sephacryl S-200HR column filtration chromatography,above 97% purity of rV270 protein was obtained.Purified rV270 that was adsorbed to 25% （v/v） Al（OH）3 adjuvant in phosphate-buffered saline （PBS） induced very high titers of antibody to rV270 in BALB/c mice and protected them （100% survival） against subcutaneous challenge with 106 CFU of Y.pestis virulent strain 141.Conclusion The completely authentic rV270 protein can be prepared by using enterokinase or factor Xa,but they exhibited extremely low cleavage activity to the corresponding recognition site.Thrombin cleavage is an efficient strategy to prepare non-tagged rV270 protein and can be easily operated in a large scale due to its relatively low cost and high cleavage efficacy.The recombinant rV270 can be used as a key component to develop a subunit vaccine of plague.
基金This work was supported by the National Key Research&Development Program of China(No.2020YFC0840900)the Beijing Municipal Science and Technology Project(No.Z201100001020004).
文摘To the Editor:In December 2019,coronavirus disease 2019 outbreak caused by the 2019 novel coronavirus(2019-nCoV)happened in Wuhan,China.Now,it has posed a worldwide public health threat.Real-time quanti-tative polymerase chain reaction(RT-qPCR)was recom-mended as an effective pathogen detection method and has played an important role in prevention and control of the current outbreak.Many research institutions have released their primer sets for RT-qPCR.If the variant sites were located in the primer regions,the efficiency of RT-qPCR would be reduced,thus possibly causing false negative results,and leading to unpredictable impact on the diagnosis of patients and the control of this outbreak.Therefore,a comprehensive investigation on 2019-nCoV genome variation is necessary to evaluate the effectiveness of current released RT-qPCR methods.
文摘With time and space resolved technique, we have recorded time resolved spectra of irradiation of the plasma induced by Nd: YAG laser ablating metal Aluminum in Ar, in which, laser pulse energy was set up to 145 mJ/pulse and the buffer pressure 100 kpa. The continuum radiation and special emission of Aluminum plasma were studied based on the records. According to time distribution of Al Ⅰ396.15 nm emission, we analyzed the time differences between characteristic and continuum radiation evolving. We tried to explain the time phases of characteristic radiation evolving with traditional theoretical model of atomic transition. As the result, we found that it was difficult to explain our experimental results with the model. In order to explain our experimental results, we need new model or to improve the traditional theoretical model of atomic transition.
文摘Congenital rubella syndrome is characterized by the triad of deafness, cataract and cardiovascular mafformations. The great majority of the cases in the literature have been usually diagnosed in infancy and childhood because of various defects at birth. However, we report a rare case of suspected congenital rubella syndrome in an adult with unilateral pulmonary artery stenosis and late-onset cataract.
基金supported by the National Standardization Committee of China(No.20081021-T-361)the Ministry of Science and Technology of the People’s Republic of Chinathe National High Technology Grant(No.2008ZX10004-006).
文摘One hundred andfifty-three isolates from the environment and 36 reference strains of the Legionella were studied with regards to their composition of cellular fatty acids as determined by gas chromatography,and then were classified into 41 groups by numerical analysis.Most reference strains formed only a single group,except L.micdadei,L.jamestowniensis,L.parisiensis,L.jorda-nis,L.feeleii and L.longbeachae,which were clustered into two or three groups.Even serological types of L.pneumophila could be clearly identified.Therefore,in this study,numerical analysis of cellular fatty acid composition is an effective method for identifying Legionella species.
