1 Results Nano-ordered composite materials consisting of organic polymers and inorganic materials have been attracting attention for the purpose of the creation of high-performance or high-functional polymeric materia...1 Results Nano-ordered composite materials consisting of organic polymers and inorganic materials have been attracting attention for the purpose of the creation of high-performance or high-functional polymeric materials. Especially,the word of "polymer hybrid" claims the blends of organic and inorganic components at nano-level dispersion. By using this idea,an enhancement of mechanical strength of organic polymers with silica particles is possible.High transparency of this material is another important ...展开更多
A theoretical approach to polycondensation reaction of Aa-Bb type Involving intramolecular cycllzatlon has been proposed by Tang Au-chin et al.. In this paper, the theoretical sol-gel distribution is tested by polycon...A theoretical approach to polycondensation reaction of Aa-Bb type Involving intramolecular cycllzatlon has been proposed by Tang Au-chin et al.. In this paper, the theoretical sol-gel distribution is tested by polycondensation of adipic acid with trimethylol propane in a sto-ichiometric ratio of 0. 8, and the effect of intramolecular cyclization is discussed in detail.展开更多
Information on co-adherence of different oral bacterial species is important for understanding interspecies interactions within oral microbial community. Current knowledge on this topic is heavily based on pariwise co...Information on co-adherence of different oral bacterial species is important for understanding interspecies interactions within oral microbial community. Current knowledge on this topic is heavily based on pariwise coaggregation of known, cultivable species. In this study, we employed a membrane binding assay coupled with polymerase chain reaction-denaturing gradient gel electrophoresis （PCR-DGGE） to systematically analyze the co-adherence profiles of oral bacterial species, and achieved a more profound knowledge beyond pairwise coaggregation. Two oral bacterial species were selected to serve as ＂bait＂： Fusobacterium nucleatum （F. nucleatum） whose ability to adhere to a multitude of oral bacterial species has been extensively studied for pairwise interactions and Streptococcus mutans （S. mutans） whose interacting partners are largely unknown. To enable screening of interacting partner species within bacterial mixtures, cells of the ＂bait＂ oral bacterium were immobilized on nitrocellulose membranes which were washed and blocked to prevent unspecific binding. The ＂prey＂ bacterial mixtures （including known species or natural saliva samples） were added, unbound ceils were washed off after the incubation period and the remaining cells were eluted using 0.2 mol.L1 glycine. Genomic DNA was extraeted, subjeeted to 16S rRNA PCR amplification and separation of the resulting PCR produets by DGGE. Selected bands were recovered from the gel, sequenced and identified via Nucleotide BLAST searches against different databases. While few bacterial species bound to S. mutans, consistent with previous findings F.. nucleatum adhered to a variety of bacterial species including uncultivable and uneharacterized onesl This new approach can more effectively analyze the co-adherence profiles of oral bacteria, and could facilitate the systematic study of interbacterial binding of oral microbial species.展开更多
目的对1例ABw亚型患者进行A型血浆置换后血型血清学变化以及是否发生溶血反应进行回顾性调查。方法使用微柱凝胶技术、微柱玻璃珠技术、盐水试管法、吸收放散等血型血清学方法及分子生物学方式进行ABO血型鉴定和基因分型,对患者血浆置...目的对1例ABw亚型患者进行A型血浆置换后血型血清学变化以及是否发生溶血反应进行回顾性调查。方法使用微柱凝胶技术、微柱玻璃珠技术、盐水试管法、吸收放散等血型血清学方法及分子生物学方式进行ABO血型鉴定和基因分型,对患者血浆置换前后实验室检查结果进行分析。结果该患者于行2000 mL A型血浆置换后转入本院,d 2检测正反定型相符;d 3检测反定B细胞凝集强度为±~1+,正反定型不符。经试管法、人源抗-B吸收放散试验确认存在B抗原,分子生物学鉴定为ABw03型。患者用A型血浆进行血浆置换后,血红蛋白、血小板计数均一过性下降,肌酐一过性轻度上升,谷丙转氨酶、谷草转氨酶持续下降,总胆红素和间接胆红素一过性下降后上升,提示存在轻微的溶血性输血反应。结论ABO亚型患者含弱A或B抗原,输注大量血浆可能引起溶血性输血反应。应严格按照ABO血型正反定型标准判断血型结果,对弱凝集采取额外实验室检查并结合分子生物学技术进行正确的判断和处理,可以减少ABO亚型的漏检,减少输血反应的发生。展开更多
[目的]探讨可溶性大豆多糖(soluble soybean polysaccharides,SSPS)对大豆分离蛋白(soybean protein isolate,SPI)凝胶形成及凝胶特性的影响。[方法]制备不同SSPS添加量的SPI悬液和凝胶,以未添加SSPS的SPI悬液和凝胶为对照。分别测定结...[目的]探讨可溶性大豆多糖(soluble soybean polysaccharides,SSPS)对大豆分离蛋白(soybean protein isolate,SPI)凝胶形成及凝胶特性的影响。[方法]制备不同SSPS添加量的SPI悬液和凝胶,以未添加SSPS的SPI悬液和凝胶为对照。分别测定结构特性、理化特性以及凝胶特性。[结果]SPI制备成凝胶的过程中,SPI与SSPS之间发生了糖基化反应,SSPS改变了蛋白的二级结构和三级结构。添加SSPS后样品zeta-电位绝对值降低、热稳定性增大;凝胶离子键、氢键、疏水相互作用及二硫键含量下降,非二硫键的共价键含量增加。添加量为10%时,SPI悬液表面疏水性降低程度最大,达到88.42%;SPI凝胶硬度下降28.85%,持水性增加了40.72%。扫描电镜结果表明,SSPS的添加导致凝胶网络疏松多孔,凝胶强度下降。[结论]SPI凝胶制备过程中添加SSPS,二者会发生糖基化反应,随SSPS添加量增多,蛋白结构特性和凝胶特性改变更明显。展开更多
核酸适配体是人工合成的短链核酸,作为分子识别元件,能够与各类靶标物质高特异性、高亲和力的结合,分为单链DNA和RNA两种类型。其中单链DNA适配体由于其稳定性比RNA适配体更好而更受欢迎,因此得到广泛应用。核酸适配体筛选通常是通过配...核酸适配体是人工合成的短链核酸,作为分子识别元件,能够与各类靶标物质高特异性、高亲和力的结合,分为单链DNA和RNA两种类型。其中单链DNA适配体由于其稳定性比RNA适配体更好而更受欢迎,因此得到广泛应用。核酸适配体筛选通常是通过配体指数富集系统进化技术(systematic evolution of ligands by exponential enrichment,SELEX)实现的,筛选能否成功在很大程度上取决于其最关键的单链制备步骤,即将双链DNA转化为相应的单链DNA。目前,存在许多方法可以制备单链DNA,包括热变性法、生物素-链霉亲和素亲和分离法、变性胶电泳分离法、核酸外切酶消化法、不对称聚合酶链式反应(polymerase chain reaction,PCR)法等。本文在总结文献报道的基础上,具体阐述了各种单链DNA制备方法的原理、优缺点及近5年的应用情况,并对这些单链DNA制备方法进行了比较和展望,以期能为成功筛选各类靶标的核酸适配体提供参考。展开更多
文摘1 Results Nano-ordered composite materials consisting of organic polymers and inorganic materials have been attracting attention for the purpose of the creation of high-performance or high-functional polymeric materials. Especially,the word of "polymer hybrid" claims the blends of organic and inorganic components at nano-level dispersion. By using this idea,an enhancement of mechanical strength of organic polymers with silica particles is possible.High transparency of this material is another important ...
文摘A theoretical approach to polycondensation reaction of Aa-Bb type Involving intramolecular cycllzatlon has been proposed by Tang Au-chin et al.. In this paper, the theoretical sol-gel distribution is tested by polycondensation of adipic acid with trimethylol propane in a sto-ichiometric ratio of 0. 8, and the effect of intramolecular cyclization is discussed in detail.
基金supported by Chinese State Scholarship Fund to R. WangUS National Institutes of Health (NIH) Grants DE020102 and GM95373 to W. Shi
文摘Information on co-adherence of different oral bacterial species is important for understanding interspecies interactions within oral microbial community. Current knowledge on this topic is heavily based on pariwise coaggregation of known, cultivable species. In this study, we employed a membrane binding assay coupled with polymerase chain reaction-denaturing gradient gel electrophoresis （PCR-DGGE） to systematically analyze the co-adherence profiles of oral bacterial species, and achieved a more profound knowledge beyond pairwise coaggregation. Two oral bacterial species were selected to serve as ＂bait＂： Fusobacterium nucleatum （F. nucleatum） whose ability to adhere to a multitude of oral bacterial species has been extensively studied for pairwise interactions and Streptococcus mutans （S. mutans） whose interacting partners are largely unknown. To enable screening of interacting partner species within bacterial mixtures, cells of the ＂bait＂ oral bacterium were immobilized on nitrocellulose membranes which were washed and blocked to prevent unspecific binding. The ＂prey＂ bacterial mixtures （including known species or natural saliva samples） were added, unbound ceils were washed off after the incubation period and the remaining cells were eluted using 0.2 mol.L1 glycine. Genomic DNA was extraeted, subjeeted to 16S rRNA PCR amplification and separation of the resulting PCR produets by DGGE. Selected bands were recovered from the gel, sequenced and identified via Nucleotide BLAST searches against different databases. While few bacterial species bound to S. mutans, consistent with previous findings F.. nucleatum adhered to a variety of bacterial species including uncultivable and uneharacterized onesl This new approach can more effectively analyze the co-adherence profiles of oral bacteria, and could facilitate the systematic study of interbacterial binding of oral microbial species.
文摘目的对1例ABw亚型患者进行A型血浆置换后血型血清学变化以及是否发生溶血反应进行回顾性调查。方法使用微柱凝胶技术、微柱玻璃珠技术、盐水试管法、吸收放散等血型血清学方法及分子生物学方式进行ABO血型鉴定和基因分型,对患者血浆置换前后实验室检查结果进行分析。结果该患者于行2000 mL A型血浆置换后转入本院,d 2检测正反定型相符;d 3检测反定B细胞凝集强度为±~1+,正反定型不符。经试管法、人源抗-B吸收放散试验确认存在B抗原,分子生物学鉴定为ABw03型。患者用A型血浆进行血浆置换后,血红蛋白、血小板计数均一过性下降,肌酐一过性轻度上升,谷丙转氨酶、谷草转氨酶持续下降,总胆红素和间接胆红素一过性下降后上升,提示存在轻微的溶血性输血反应。结论ABO亚型患者含弱A或B抗原,输注大量血浆可能引起溶血性输血反应。应严格按照ABO血型正反定型标准判断血型结果,对弱凝集采取额外实验室检查并结合分子生物学技术进行正确的判断和处理,可以减少ABO亚型的漏检,减少输血反应的发生。
文摘[目的]探讨可溶性大豆多糖(soluble soybean polysaccharides,SSPS)对大豆分离蛋白(soybean protein isolate,SPI)凝胶形成及凝胶特性的影响。[方法]制备不同SSPS添加量的SPI悬液和凝胶,以未添加SSPS的SPI悬液和凝胶为对照。分别测定结构特性、理化特性以及凝胶特性。[结果]SPI制备成凝胶的过程中,SPI与SSPS之间发生了糖基化反应,SSPS改变了蛋白的二级结构和三级结构。添加SSPS后样品zeta-电位绝对值降低、热稳定性增大;凝胶离子键、氢键、疏水相互作用及二硫键含量下降,非二硫键的共价键含量增加。添加量为10%时,SPI悬液表面疏水性降低程度最大,达到88.42%;SPI凝胶硬度下降28.85%,持水性增加了40.72%。扫描电镜结果表明,SSPS的添加导致凝胶网络疏松多孔,凝胶强度下降。[结论]SPI凝胶制备过程中添加SSPS,二者会发生糖基化反应,随SSPS添加量增多,蛋白结构特性和凝胶特性改变更明显。
文摘核酸适配体是人工合成的短链核酸,作为分子识别元件,能够与各类靶标物质高特异性、高亲和力的结合,分为单链DNA和RNA两种类型。其中单链DNA适配体由于其稳定性比RNA适配体更好而更受欢迎,因此得到广泛应用。核酸适配体筛选通常是通过配体指数富集系统进化技术(systematic evolution of ligands by exponential enrichment,SELEX)实现的,筛选能否成功在很大程度上取决于其最关键的单链制备步骤,即将双链DNA转化为相应的单链DNA。目前,存在许多方法可以制备单链DNA,包括热变性法、生物素-链霉亲和素亲和分离法、变性胶电泳分离法、核酸外切酶消化法、不对称聚合酶链式反应(polymerase chain reaction,PCR)法等。本文在总结文献报道的基础上,具体阐述了各种单链DNA制备方法的原理、优缺点及近5年的应用情况,并对这些单链DNA制备方法进行了比较和展望,以期能为成功筛选各类靶标的核酸适配体提供参考。
