目的 在规范化的结核分枝杆菌（Mycobacterium tuberculosis，MTB）可变数目串联重复序列（variable number of tandem repeats，VNTR）基因分型的基础上，构建我国31个省（自治区、直辖市）VNTR数据库，每个省优化一套VNTR位点组合，...目的 在规范化的结核分枝杆菌（Mycobacterium tuberculosis，MTB）可变数目串联重复序列（variable number of tandem repeats，VNTR）基因分型的基础上，构建我国31个省（自治区、直辖市）VNTR数据库，每个省优化一套VNTR位点组合，为我国结核病预防控制策略的制定提供科学依据。方法 对2007－2008年全国结核病耐药性基线调查的4 116株MTB15位点VNTR（15-VNTR）基因分型。汉高指数（Hunter-Gaston Index，HGI）分析每个位点的分辨率。依据谱系流行特征，以分辨率高和稳定性强为原则，为各省设计一套VNTR优化组合（12-VNTR、10-VNTR、8-VNTR和5-VNTR），采用HGI和成簇率进行评价。结果 完成了涵盖率为96.36%（3 966/4 116）MTB完整15-VNTR图谱。发现QUB11b、MIRU26等7个高分辨率位点；QUB26、MIRU16、Mtub21、QUB11b在部分地区遗传稳定性差。内蒙古自治区、重庆市、黑龙江省的最优组合为10-VNTR，其他各省的最佳组合为8-VNTR。结论 VNTR数据库的建立将推动全国范围MTB传染源的追踪；各省优化VNTR组合的推出有助于当地结核病疫情的监测和群体遗传学的研究。展开更多
Superparamagnetic iron oxide （SPIO） nanoparticle clusters are one unique form which can enhance magnetic relaxivity and improve the magnetic resonance imaging contrast at the same iron concentration, comparing to si...Superparamagnetic iron oxide （SPIO） nanoparticle clusters are one unique form which can enhance magnetic relaxivity and improve the magnetic resonance imaging contrast at the same iron concentration, comparing to single SPIO nanoparticles. Controlling of cluster size and other structural parameters have drawn great interests in this field to further improve their magnetic properties. In this study, we investigated how the interparticle distance （also known as neighbor distance） of SP10 nanocrystals within clusters affect their magnetic relaxation behaviors. To adjust the neighbor distance, different amount of cholesterol （CHO） was chosen as model spacers embedded into SPIO nanocluster systems with the help of amphiphilic diblock copolymer poly（ethylene glyco）-polyester. Small- angle X-ray scattering was applied to quantify the neighbor distance of SPIO clusters. The results demonstrated that the averaged SPIO nanocrystal neighbor distance of nan- oclusters increased with higher amount of added CHO. Moreover, these SPIO nanocrystal clusters had the promi- nent magnetic relaxation properties. Simultaneously, con- trolling of SPIO nanocrystal neighbor distance can regulate the saturation magnetization （Ms） and magnetic resonance （MR） T2 relaxation of the aggregation, and ultimately obtain better MR contrast effects with decreased neighbor distance.展开更多
文摘目的 在规范化的结核分枝杆菌（Mycobacterium tuberculosis，MTB）可变数目串联重复序列（variable number of tandem repeats，VNTR）基因分型的基础上，构建我国31个省（自治区、直辖市）VNTR数据库，每个省优化一套VNTR位点组合，为我国结核病预防控制策略的制定提供科学依据。方法 对2007－2008年全国结核病耐药性基线调查的4 116株MTB15位点VNTR（15-VNTR）基因分型。汉高指数（Hunter-Gaston Index，HGI）分析每个位点的分辨率。依据谱系流行特征，以分辨率高和稳定性强为原则，为各省设计一套VNTR优化组合（12-VNTR、10-VNTR、8-VNTR和5-VNTR），采用HGI和成簇率进行评价。结果 完成了涵盖率为96.36%（3 966/4 116）MTB完整15-VNTR图谱。发现QUB11b、MIRU26等7个高分辨率位点；QUB26、MIRU16、Mtub21、QUB11b在部分地区遗传稳定性差。内蒙古自治区、重庆市、黑龙江省的最优组合为10-VNTR，其他各省的最佳组合为8-VNTR。结论 VNTR数据库的建立将推动全国范围MTB传染源的追踪；各省优化VNTR组合的推出有助于当地结核病疫情的监测和群体遗传学的研究。
基金supported by the National Key Basic Research Program of China (2013CB933903)the National High Technology R&D Program of China (2012BAI23B08)the National Natural Science Foundation of China (20974065, 51173117 and 50830107)
文摘Superparamagnetic iron oxide （SPIO） nanoparticle clusters are one unique form which can enhance magnetic relaxivity and improve the magnetic resonance imaging contrast at the same iron concentration, comparing to single SPIO nanoparticles. Controlling of cluster size and other structural parameters have drawn great interests in this field to further improve their magnetic properties. In this study, we investigated how the interparticle distance （also known as neighbor distance） of SP10 nanocrystals within clusters affect their magnetic relaxation behaviors. To adjust the neighbor distance, different amount of cholesterol （CHO） was chosen as model spacers embedded into SPIO nanocluster systems with the help of amphiphilic diblock copolymer poly（ethylene glyco）-polyester. Small- angle X-ray scattering was applied to quantify the neighbor distance of SPIO clusters. The results demonstrated that the averaged SPIO nanocrystal neighbor distance of nan- oclusters increased with higher amount of added CHO. Moreover, these SPIO nanocrystal clusters had the promi- nent magnetic relaxation properties. Simultaneously, con- trolling of SPIO nanocrystal neighbor distance can regulate the saturation magnetization （Ms） and magnetic resonance （MR） T2 relaxation of the aggregation, and ultimately obtain better MR contrast effects with decreased neighbor distance.
