【目的】猪繁殖与呼吸综合征(porcine reproductive and respiratory syndrome,PRRS),俗称"蓝耳病",是由猪繁殖与呼吸综合征病毒(porcine reproductive and respiratory syndrome virus,PRRSV)引起的一种高致死性传染病,对世...【目的】猪繁殖与呼吸综合征(porcine reproductive and respiratory syndrome,PRRS),俗称"蓝耳病",是由猪繁殖与呼吸综合征病毒(porcine reproductive and respiratory syndrome virus,PRRSV)引起的一种高致死性传染病,对世界养猪业造成了巨大的经济损失。由于PRRSV遗传变异性较大,因此国内外并未有理想疫苗能够对此病进行有效防制。Cluster of differentiation 163(CD163)是PRRSV感染猪肺泡巨噬细胞(porcine alveolar macrophage,PAM)的受体之一,研究旨在利用CRISPR/Cas9技术结合体细胞核移植技术制备CD163基因编辑的大白猪。【方法】针对猪CD163基因的第7外显子设计构建CRISPR/Cas9基因编辑载体;转染大白猪胎儿成纤维细胞,获得基因编辑阳性细胞克隆;以基因编辑细胞为核供体、体外成熟的猪卵母细胞为核受体构建克隆胚胎;胚胎移植到受体母猪生产CD163基因编辑猪,并进行后续的扩繁试验。【结果】设计的g RNA能够高效的识别靶位点。对获得的127个细胞单克隆进行PCR和测序显示,共有21个克隆发生突变,其中14个克隆为单等位基因突变或双等位基因杂合突变,7个克隆为双等位基因纯合突变。通过体细胞核移植技术,成功获得了CD163双等位基因编辑的纯合大白猪;并获得首批F1代CD163基因编辑仔猪,目前健康状态良好。随后将有更多的F1代CD163基因编辑猪陆续出生。【结论】制备的无抗性筛选标记的CD163双等位基因编辑猪,能够安全并快速地为培育抗PRRSV新品种猪提供育种材料。展开更多
为进一步对比研究微米硼粉与团聚硼颗粒的氧化机理,利用热重(TGA)及微商热重(DTG)法研究了其在空气中不同升温速率下的非等温氧化动力学;通过Ozawa法和Kissinger法提出了硼粉和团聚硼的氧化动力学参数;结果表明,低温下微米硼粉的氧化过...为进一步对比研究微米硼粉与团聚硼颗粒的氧化机理,利用热重(TGA)及微商热重(DTG)法研究了其在空气中不同升温速率下的非等温氧化动力学;通过Ozawa法和Kissinger法提出了硼粉和团聚硼的氧化动力学参数;结果表明,低温下微米硼粉的氧化过程可分为3步; Kissinger法和Ozawa法计算的微米硼粉活化能分别为199.0 k J/mol和206.1 k J/mol,团聚硼内硼粉氧化阶段的活化能分别为256.0 k J/mol和259.5 k J/mol,两种方法计算结果基本一致;经Coats-Redfern法推导出,微米硼粉氧化的3个阶段动力学机理方程式分别为α2、(1-α)-n(n=1,2)和α1/n(n=1,2,3),团聚硼颗粒氧化三个阶段则分别符合[-ln(1-α)]1/n(n=2,3),α1/n(n=1,2,3)和α1/n(n=1,2,3)机理函数。展开更多
Ag loaded mesoporous silica-embedded TiO_2 nanocomposites were successfully synthesized via two different routes,including one-pot solvothermal method and solvothermal-chemical reduction method,both using Titanium（Ⅳ...Ag loaded mesoporous silica-embedded TiO_2 nanocomposites were successfully synthesized via two different routes,including one-pot solvothermal method and solvothermal-chemical reduction method,both using Titanium（Ⅳ） n-butoxide（Ti（OC_4H_9）_4） as a precursor,formic acid as a solvent and reducing agent,silver nitrate as a silver source and tetraethyl silicate（TEOS） as a stabilizer.The transmission electron microscopic（TEM） images showed that silica-embedded anatase TiO_2 sample exhibited approximately rhombic shape and Ag nanoparticles could be embedded into the nanocomposites or deposited on the surface with high dispersion.The N_2 adsorption-desorption isotherms indicated that the silica-embedded anatase TiO_2 had obvious mesoporous structure with a BET specific surface area of 203.5 m^2·g^-1.All Ag loaded silica-embedded TiO_2composites showed a higher photocatalytic H2-generation activity from water splitting under simulative solar light irradiation than that of TiO2 products.The maximum H_2 production rate（6.10 mmol·h^-1·g^-1） was obtained over 2%Ag/silica-embedded TiO2 nanocomposites（2%Ag/MST） prepared by solvothermal-chemical reduction method,which was 20 times that achieved on the silica-embedded TiO2 sample.The enhanced photocatalytic H2-evolution activity of Ag loaded mesoporous silica-embedded TiO2 nanocomposites can be attributed to the multi-function of surface Ag co-catalyst,mesoporous structure,and embedding of silica.展开更多
文摘为进一步对比研究微米硼粉与团聚硼颗粒的氧化机理,利用热重(TGA)及微商热重(DTG)法研究了其在空气中不同升温速率下的非等温氧化动力学;通过Ozawa法和Kissinger法提出了硼粉和团聚硼的氧化动力学参数;结果表明,低温下微米硼粉的氧化过程可分为3步; Kissinger法和Ozawa法计算的微米硼粉活化能分别为199.0 k J/mol和206.1 k J/mol,团聚硼内硼粉氧化阶段的活化能分别为256.0 k J/mol和259.5 k J/mol,两种方法计算结果基本一致;经Coats-Redfern法推导出,微米硼粉氧化的3个阶段动力学机理方程式分别为α2、(1-α)-n(n=1,2)和α1/n(n=1,2,3),团聚硼颗粒氧化三个阶段则分别符合[-ln(1-α)]1/n(n=2,3),α1/n(n=1,2,3)和α1/n(n=1,2,3)机理函数。
基金Funded by Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions
文摘Ag loaded mesoporous silica-embedded TiO_2 nanocomposites were successfully synthesized via two different routes,including one-pot solvothermal method and solvothermal-chemical reduction method,both using Titanium（Ⅳ） n-butoxide（Ti（OC_4H_9）_4） as a precursor,formic acid as a solvent and reducing agent,silver nitrate as a silver source and tetraethyl silicate（TEOS） as a stabilizer.The transmission electron microscopic（TEM） images showed that silica-embedded anatase TiO_2 sample exhibited approximately rhombic shape and Ag nanoparticles could be embedded into the nanocomposites or deposited on the surface with high dispersion.The N_2 adsorption-desorption isotherms indicated that the silica-embedded anatase TiO_2 had obvious mesoporous structure with a BET specific surface area of 203.5 m^2·g^-1.All Ag loaded silica-embedded TiO_2composites showed a higher photocatalytic H2-generation activity from water splitting under simulative solar light irradiation than that of TiO2 products.The maximum H_2 production rate（6.10 mmol·h^-1·g^-1） was obtained over 2%Ag/silica-embedded TiO2 nanocomposites（2%Ag/MST） prepared by solvothermal-chemical reduction method,which was 20 times that achieved on the silica-embedded TiO2 sample.The enhanced photocatalytic H2-evolution activity of Ag loaded mesoporous silica-embedded TiO2 nanocomposites can be attributed to the multi-function of surface Ag co-catalyst,mesoporous structure,and embedding of silica.
