目的建立液相色谱串联质谱法同时定性定量测定鸡蛋粉中16种磺胺类药物残留量的分析方法。方法样品中的16种磺胺类物质用0.2%甲酸乙腈提取后,由Oasis Prime HLB固相萃取柱净化,经SB C18色谱柱(2.1 mm×150 mm, 3.5μm)分离,以0.1%甲...目的建立液相色谱串联质谱法同时定性定量测定鸡蛋粉中16种磺胺类药物残留量的分析方法。方法样品中的16种磺胺类物质用0.2%甲酸乙腈提取后,由Oasis Prime HLB固相萃取柱净化,经SB C18色谱柱(2.1 mm×150 mm, 3.5μm)分离,以0.1%甲酸溶液和乙腈为流动相进行梯度洗脱,流速为0.25 mL/min,柱温为30℃。多反应监测模式测定,外标法定量。结果 16种目标化合物线性良好,相关系数均大于0.9992,方法的最低检出限在0.1~0.5μg/L之间,大部分待测物的平均回收率为79.9%~95.8%,相对标准偏差为3.1%~12.0%。结论该方法快速、准确,适用于鸡蛋粉中16种磺胺类药物残留量的检测。展开更多
Supercooling of the microencapsulated phase change materials（PCMs） during cooling usually happens. This phenomenon can interfere with heat transfer and is necessary to further overcome. In this study, mela- mine-for...Supercooling of the microencapsulated phase change materials（PCMs） during cooling usually happens. This phenomenon can interfere with heat transfer and is necessary to further overcome. In this study, mela- mine-formaldehyde microcapsules containing two n-alkane PCMs, namely, n-dodecane（Cl2） or n-tetradecane（C14） were prepared by in situ polymerization. A small amount of n-hexatriacontane（C36） was introduced as an organic ge- lator into the core of microcapsules to cope with the supercooling problem. Analyses demonstrate that supercooling of the microencapsulated C12 or C14 was significantly suppressed by adding 3%（mass fraction） C36, without changing the spherical morphology and dispersibility. It could be also found that the enthalpy of microencapsulated CI2 or C14 containing C36 was similar to that of microencapsulated n-alkanes without C36, whereas the difference between onsets of crystallization and melting（degree of supercooling） is similar to that of those of pure n-alkanes, suggesting the re- markable suppression ability of the organic gelator on supercooling.展开更多
When devoured by macrophages,Mycobacterium tuberculosis remains persistent in macrophages and gains energy through the glyoxylate bypass to maintain its long-term existence in host cells.Therefore it is possible to st...When devoured by macrophages,Mycobacterium tuberculosis remains persistent in macrophages and gains energy through the glyoxylate bypass to maintain its long-term existence in host cells.Therefore it is possible to stop persistent infections by interdicting the glyoxylate bypass in which the isocitrate lyase（ICL） is the key rate-limiting enzyme and a persistence factor.ICL is the target of anti-TB（TB：tubercular） drugs,which could screen ICL out and effectively inhibit the activity of ICL in Mycobacterium tuberculosis,and because of this,anti-TB drugs can be used to kill persistent Mycobacterium tuberculosis.In this study,the ICL gene of the Mycobacterium tuberculosis H37Rv was cloned successfully and recombinant protein with bioactivity was obtained through the enzyme characteristic appraisal.The specific activity of the recombined ICL is 24μmol·mg-1·min-1.The recombined ICL protein was used as the target,and phages which can specifically combine to ICL were screened in the phage 7 peptide library.According to the results of the ELISA and DNA sequence detection,eventually three 7-peptide chains were synthesized.Then the peptide chains were reacted with ICL,respectively,to detect their inhibitory effects on ICL.The results show that all the three 7-peptide chains possessed varying inhibitory effects on the activity of ICL.This study provided lead compounds for the research and development of new peptide anti-TB drugs.展开更多
目的建立高效液相色谱-高分辨飞行时间质谱联用技术(high performance liquid chromatography tandem triple-time-of-flight mass spectrometry,HPLC-Triple-TOF MS)筛选中国和俄罗斯人参中人参皂苷差异化合物的分析方法。方法采用HPLC...目的建立高效液相色谱-高分辨飞行时间质谱联用技术(high performance liquid chromatography tandem triple-time-of-flight mass spectrometry,HPLC-Triple-TOF MS)筛选中国和俄罗斯人参中人参皂苷差异化合物的分析方法。方法采用HPLC-Triple-TOF MS对来源于中国和俄罗斯的48例人参样品进行测定,通过高分辨飞行时间质谱分析,对48例样品的特征峰质谱信息进行提取,通过得到的一级质谱精确质荷比和二级质谱碎片信息,结合软件数据库进行成分鉴别后,采用主成分分析(principal component analysis,PCA)和偏最小二乘判别分析(partial least squares discrimination analysis,PLS-DA)对得到的数据进行处理,筛选差异组分。结果经上述方法进行处理和分析后,中国和俄罗斯人参样品间的组分得到明显区分,初步筛选并鉴定出了中国和俄罗斯人参间14种差异显著的人参皂苷类化学成分。结论本研究成功建立了基于高效液相色谱-高分辨飞行时间质谱联用技术鉴别中国和俄罗斯人参的分析方法,建立的方法准确、可靠,可用于中国和俄罗斯人参的产地鉴别和溯源。展开更多
A variational-integral perturbation method(VIPM)has been established by combining the variational perturbation with the integral perturbation.We present the results obtained by the application of VIPM to the ground an...A variational-integral perturbation method(VIPM)has been established by combining the variational perturbation with the integral perturbation.We present the results obtained by the application of VIPM to the ground and excited states associated with the Zeeman effect on a hydrogen atom.We construct correction wave functions and calculate energy corrections for the ground state and some high excited states.These values are compared with results of Smith and Jason et al.;our results are more accurate than those from Smith and Jason,especially in the 4f excited state where we find a very interesting result that when magnetic fields increase,the energy level trap appears.展开更多
文摘目的建立液相色谱串联质谱法同时定性定量测定鸡蛋粉中16种磺胺类药物残留量的分析方法。方法样品中的16种磺胺类物质用0.2%甲酸乙腈提取后,由Oasis Prime HLB固相萃取柱净化,经SB C18色谱柱(2.1 mm×150 mm, 3.5μm)分离,以0.1%甲酸溶液和乙腈为流动相进行梯度洗脱,流速为0.25 mL/min,柱温为30℃。多反应监测模式测定,外标法定量。结果 16种目标化合物线性良好,相关系数均大于0.9992,方法的最低检出限在0.1~0.5μg/L之间,大部分待测物的平均回收率为79.9%~95.8%,相对标准偏差为3.1%~12.0%。结论该方法快速、准确,适用于鸡蛋粉中16种磺胺类药物残留量的检测。
文摘Supercooling of the microencapsulated phase change materials（PCMs） during cooling usually happens. This phenomenon can interfere with heat transfer and is necessary to further overcome. In this study, mela- mine-formaldehyde microcapsules containing two n-alkane PCMs, namely, n-dodecane（Cl2） or n-tetradecane（C14） were prepared by in situ polymerization. A small amount of n-hexatriacontane（C36） was introduced as an organic ge- lator into the core of microcapsules to cope with the supercooling problem. Analyses demonstrate that supercooling of the microencapsulated C12 or C14 was significantly suppressed by adding 3%（mass fraction） C36, without changing the spherical morphology and dispersibility. It could be also found that the enthalpy of microencapsulated CI2 or C14 containing C36 was similar to that of microencapsulated n-alkanes without C36, whereas the difference between onsets of crystallization and melting（degree of supercooling） is similar to that of those of pure n-alkanes, suggesting the re- markable suppression ability of the organic gelator on supercooling.
基金Supported by the Technology Development Funds of Education Department of Jilin Province,China(No.2008110)
文摘When devoured by macrophages,Mycobacterium tuberculosis remains persistent in macrophages and gains energy through the glyoxylate bypass to maintain its long-term existence in host cells.Therefore it is possible to stop persistent infections by interdicting the glyoxylate bypass in which the isocitrate lyase（ICL） is the key rate-limiting enzyme and a persistence factor.ICL is the target of anti-TB（TB：tubercular） drugs,which could screen ICL out and effectively inhibit the activity of ICL in Mycobacterium tuberculosis,and because of this,anti-TB drugs can be used to kill persistent Mycobacterium tuberculosis.In this study,the ICL gene of the Mycobacterium tuberculosis H37Rv was cloned successfully and recombinant protein with bioactivity was obtained through the enzyme characteristic appraisal.The specific activity of the recombined ICL is 24μmol·mg-1·min-1.The recombined ICL protein was used as the target,and phages which can specifically combine to ICL were screened in the phage 7 peptide library.According to the results of the ELISA and DNA sequence detection,eventually three 7-peptide chains were synthesized.Then the peptide chains were reacted with ICL,respectively,to detect their inhibitory effects on ICL.The results show that all the three 7-peptide chains possessed varying inhibitory effects on the activity of ICL.This study provided lead compounds for the research and development of new peptide anti-TB drugs.
基金Supported by the National Natural Science Foundation of China under Grant No 11175064the Foundation of the Science and Technology of Hunan Province under Grant No 2011CK3013.
文摘A variational-integral perturbation method(VIPM)has been established by combining the variational perturbation with the integral perturbation.We present the results obtained by the application of VIPM to the ground and excited states associated with the Zeeman effect on a hydrogen atom.We construct correction wave functions and calculate energy corrections for the ground state and some high excited states.These values are compared with results of Smith and Jason et al.;our results are more accurate than those from Smith and Jason,especially in the 4f excited state where we find a very interesting result that when magnetic fields increase,the energy level trap appears.
