A mixed culture of bioleaching microorganisms was enriched.Then the mixed culture was preserved by liquid nitrogen cryopreservation for 6 months and 12 months,respectively,using PEG-2000 as the protective agent.The ch...A mixed culture of bioleaching microorganisms was enriched.Then the mixed culture was preserved by liquid nitrogen cryopreservation for 6 months and 12 months,respectively,using PEG-2000 as the protective agent.The chalcopyrite leaching ability,activity and diversity of the mixed culture before and after preservation were compared.The results showed that the copper extraction rate was 95.7%in chalcopyrite bioleaching within 20 d by the original culture.After cryopreservation for 6 months and 12 months,the copper extraction rate of the mixed culture was 94.9%within 25 d and 93.6%within 35 d,respectively.The cell viability achieved 87%and 41%after being preserved for 6 months and 12 months,respectively.Furthermore,the ecology analysis identified Acidithiobacillus ferrooxidans,Acidithiobacillus caldus,Sulfobacillus thermotolerans and Pseudomonas aeruginosa in the original mixed culture.After cryopreservation for 12 months,the composition of community changed,but the predominant microorganisms still existed.展开更多
目的:本研究旨在通过不同方法修饰羟基磷灰石纳米颗粒并检测其稳定性及分散性。方法:首先采用水合热合成法制备羟基磷灰石纳米颗粒,然后用透射电镜(TEM)和场发射扫描电镜(SEM)对其表面形态结构进行表征。我们首次用溴化十六烷三甲基铵(C...目的:本研究旨在通过不同方法修饰羟基磷灰石纳米颗粒并检测其稳定性及分散性。方法:首先采用水合热合成法制备羟基磷灰石纳米颗粒,然后用透射电镜(TEM)和场发射扫描电镜(SEM)对其表面形态结构进行表征。我们首次用溴化十六烷三甲基铵(CTAB),PEG2000和人血清对羟基磷灰石纳米颗粒通过共价结合或表面吸附的方式进行表面嫁接,并利用透射电镜,傅里叶红外光谱(FT-IR)和X射线衍射(XRD)对新合成的这三种纳米羟基磷灰石复合物的形貌,结构和晶粒粒径进行表征。对这三种羟基磷灰石纳米颗粒悬浮液的时间沉降曲线进行分析。在分散性上通过检测这三种羟基磷灰石复合物悬浮液在不同pH值下的Zeta电位并绘制Zeta-pH曲线。结果:我们发现CTAB修饰的羟基磷灰石纳米颗悬浮液的悬浮稳定性最佳,其次是PEG2000,最后是人血清。在pH=7.0时,CTAB修饰的羟基磷灰石纳米颗粒的zeta电位值是25.68 m V,而PEG2000修饰的Zeta电位是4.32m V,人血清修饰的Zeta电位是-13.23m V。结论:CTAB表面修饰的羟基磷灰石纳米颗粒相对于其它两种表面活性剂复合物具有更好的分散性和悬浮稳定性,与DNA/RNA结合能力更强。本课题的结果给羟基磷灰石纳米颗粒载体的应用提供了一种新的选择,有望利用亲和力更高的基因载体实现基因治疗,具有广阔的应用前景。展开更多
Y2O3:Eu3+ powders were synthesized by combustion method and the influence of dispersant was investigated.XRD analysis indicated that the particle size increased with a small amount of dispersant firstly and then decre...Y2O3:Eu3+ powders were synthesized by combustion method and the influence of dispersant was investigated.XRD analysis indicated that the particle size increased with a small amount of dispersant firstly and then decreased with a further increase of dispersant.The morphologies of the powders were studied by scanning electron microscopy(SEM) and high-resolution transmission electron microscopy(HRTEM).SEM images revealed that an appropriate amount of dispersant could reduce the agglomeration significantly.Due ...展开更多
基金Projects(31470230,51320105006,51604308)supported by the National Natural Science Foundation of ChinaProject(2017RS3003)supported by the Youth Talent Foundation of Hunan Province of China+2 种基金Project(2018JJ2486)supported by the Natural Science Foundation of Hunan Province of ChinaProject(2018WK2012)supported by the Key Research and Development Projects in Hunan Province,ChinaProject(2018zzts767)supported by the Fundamental Research Funds for the Central Universities,China。
文摘A mixed culture of bioleaching microorganisms was enriched.Then the mixed culture was preserved by liquid nitrogen cryopreservation for 6 months and 12 months,respectively,using PEG-2000 as the protective agent.The chalcopyrite leaching ability,activity and diversity of the mixed culture before and after preservation were compared.The results showed that the copper extraction rate was 95.7%in chalcopyrite bioleaching within 20 d by the original culture.After cryopreservation for 6 months and 12 months,the copper extraction rate of the mixed culture was 94.9%within 25 d and 93.6%within 35 d,respectively.The cell viability achieved 87%and 41%after being preserved for 6 months and 12 months,respectively.Furthermore,the ecology analysis identified Acidithiobacillus ferrooxidans,Acidithiobacillus caldus,Sulfobacillus thermotolerans and Pseudomonas aeruginosa in the original mixed culture.After cryopreservation for 12 months,the composition of community changed,but the predominant microorganisms still existed.
文摘目的:本研究旨在通过不同方法修饰羟基磷灰石纳米颗粒并检测其稳定性及分散性。方法:首先采用水合热合成法制备羟基磷灰石纳米颗粒,然后用透射电镜(TEM)和场发射扫描电镜(SEM)对其表面形态结构进行表征。我们首次用溴化十六烷三甲基铵(CTAB),PEG2000和人血清对羟基磷灰石纳米颗粒通过共价结合或表面吸附的方式进行表面嫁接,并利用透射电镜,傅里叶红外光谱(FT-IR)和X射线衍射(XRD)对新合成的这三种纳米羟基磷灰石复合物的形貌,结构和晶粒粒径进行表征。对这三种羟基磷灰石纳米颗粒悬浮液的时间沉降曲线进行分析。在分散性上通过检测这三种羟基磷灰石复合物悬浮液在不同pH值下的Zeta电位并绘制Zeta-pH曲线。结果:我们发现CTAB修饰的羟基磷灰石纳米颗悬浮液的悬浮稳定性最佳,其次是PEG2000,最后是人血清。在pH=7.0时,CTAB修饰的羟基磷灰石纳米颗粒的zeta电位值是25.68 m V,而PEG2000修饰的Zeta电位是4.32m V,人血清修饰的Zeta电位是-13.23m V。结论:CTAB表面修饰的羟基磷灰石纳米颗粒相对于其它两种表面活性剂复合物具有更好的分散性和悬浮稳定性,与DNA/RNA结合能力更强。本课题的结果给羟基磷灰石纳米颗粒载体的应用提供了一种新的选择,有望利用亲和力更高的基因载体实现基因治疗,具有广阔的应用前景。
基金supported by the National Natural Science Foundation of China (10774140)Knowledge Innovation Project of the Chinese Academy of Sciences (KJCX2-YW-M11)+1 种基金Specialized Research Fund for the Doctoral Program of Higher Education (20060358054)Special Foundation for Talents of Anhui Province,China (2007Z021)
文摘Y2O3:Eu3+ powders were synthesized by combustion method and the influence of dispersant was investigated.XRD analysis indicated that the particle size increased with a small amount of dispersant firstly and then decreased with a further increase of dispersant.The morphologies of the powders were studied by scanning electron microscopy(SEM) and high-resolution transmission electron microscopy(HRTEM).SEM images revealed that an appropriate amount of dispersant could reduce the agglomeration significantly.Due ...
