Mantle pieces of Hyriopisis cumingii was treated by three kinds of solution,These mantle pieces were inserted together with paraffin nucleuses into the connective tissue of three groups of Hyriopisis cumingii.These op...Mantle pieces of Hyriopisis cumingii was treated by three kinds of solution,These mantle pieces were inserted together with paraffin nucleuses into the connective tissue of three groups of Hyriopisis cumingii.These operated animals were cultured in a pool for a month.Several pearl sacs were put out and immersed by Bouin's solution after every five days.Sections of each animals were made by histological method.Those without treatment were in a control group.Observations of these sections showed that cytochrome c and yolk lecithin have an accelerated roles on pearl sac development and pearl layer secretion.No effects on pearl sac development by polyvinyplyrrolidone(PVP).展开更多
针对某款通用芯片受到电磁兼容性(electromagnetic magnetic compatibility, EMC)干扰时出现的发动机异常现象,对其原因进行了研究,确定干扰来源,并在传感器设计、线束布置及发动机控制模块(engine control module, ECM)中传感器供电电...针对某款通用芯片受到电磁兼容性(electromagnetic magnetic compatibility, EMC)干扰时出现的发动机异常现象,对其原因进行了研究,确定干扰来源,并在传感器设计、线束布置及发动机控制模块(engine control module, ECM)中传感器供电电源电平衡方向提出改进措施。通过优化线束布置和调整ECM传感器供电电源模块,减少传感器供电电压波动,从而有效降低干扰。展开更多
This paper presents development of a quartz crystal microbalance (QCM) biosensor for real-time de- tection of E. coli O157:H7 DNA based on nanogold particles amplification. Many inner Au nanoparticles were immobilized...This paper presents development of a quartz crystal microbalance (QCM) biosensor for real-time de- tection of E. coli O157:H7 DNA based on nanogold particles amplification. Many inner Au nanoparticles were immobilized onto the thioled surface of the Au electrode, then more specific thiolated sin- gle-stranded DNA (ssDNA) probes could be fixed through Au-SH bonding. The hybridization was in- duced by exposing the ssDNA probe to the complementary target DNA of E. coli O157:H7 gene eaeA, then resulted in a mass change and corresponding frequency shifts ( △f ) of the QCM. The outer avidin-coated Au nanoparticles could combine with the target DNA to increase the mass. The electro- chemical techniques, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were adopted to manifest and character each step. The target DNA corresponding to 2.0×103 colony forming unit (CFU)/mL E. coli O157:H7 cells can be detected by this biosensor, so it is practical to develop a sensitive and effective QCM biosensor for pathogenic bacteria detection based on specific DNA analy- sis. The piezoelectric biosensing system has potential for further applications, such as food safety and environment monitoring, and this approach lays the groundwork for incorporating the method into an integrated system for in-field bacteria detection.展开更多
The synthesis of norvancomycin (NVan)-capped silver nanoparticles (Ag@NVan) and their notable in vitro antibacterial activities against E. coli, a Gram-negative bacterial strain (GNB), are reported here. Mercaptoaceti...The synthesis of norvancomycin (NVan)-capped silver nanoparticles (Ag@NVan) and their notable in vitro antibacterial activities against E. coli, a Gram-negative bacterial strain (GNB), are reported here. Mercaptoacetic acid-stabilized spherical silver nanoparticles with a diameter of 16±4 nm are prepared by a simple chemical reaction. The formation process of the silver nanoparticles is investigated by UV-visible (UV-vis) spectroscopy and transmission electron microscopy (TEM). NVan is then grafted to the terminal carboxyl of the mercaptoacetic acid in the presence of N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDAC). The TEM images of single bacteria treated with Ag@NVan show that plenty of Ag@NVan aggregate in the cell wall of E. coli. A possible antibacterial mechanism is proposed that silver nanoparticles may help destroy the stability of the outer membrane of E. coli, which makes NVan easier to bind to the nether part of the peptidoglycan structure. The antibacterial activities of silver nanoparticles on their own, together with the rigid polyvalent interaction between Ag@NVan and cell wall, enables Ag@NVan to be an effective inhibitor of GNB. This kind of bionanocomposites might be used as novel bactericidal materials and we also provide an effective synthesis method for preparing functional bioconjugated nanoparticles here.展开更多
文摘Mantle pieces of Hyriopisis cumingii was treated by three kinds of solution,These mantle pieces were inserted together with paraffin nucleuses into the connective tissue of three groups of Hyriopisis cumingii.These operated animals were cultured in a pool for a month.Several pearl sacs were put out and immersed by Bouin's solution after every five days.Sections of each animals were made by histological method.Those without treatment were in a control group.Observations of these sections showed that cytochrome c and yolk lecithin have an accelerated roles on pearl sac development and pearl layer secretion.No effects on pearl sac development by polyvinyplyrrolidone(PVP).
文摘针对某款通用芯片受到电磁兼容性(electromagnetic magnetic compatibility, EMC)干扰时出现的发动机异常现象,对其原因进行了研究,确定干扰来源,并在传感器设计、线束布置及发动机控制模块(engine control module, ECM)中传感器供电电源电平衡方向提出改进措施。通过优化线束布置和调整ECM传感器供电电源模块,减少传感器供电电压波动,从而有效降低干扰。
基金the National Natural Science Foundation of China (Grant No. 30570492)the Project of State Key Laboratory of Transducer Technology of China (Grant No. SKT0403)the Zhejiang Province Natural Science Foundation of China (Grant No. R205505)
文摘This paper presents development of a quartz crystal microbalance (QCM) biosensor for real-time de- tection of E. coli O157:H7 DNA based on nanogold particles amplification. Many inner Au nanoparticles were immobilized onto the thioled surface of the Au electrode, then more specific thiolated sin- gle-stranded DNA (ssDNA) probes could be fixed through Au-SH bonding. The hybridization was in- duced by exposing the ssDNA probe to the complementary target DNA of E. coli O157:H7 gene eaeA, then resulted in a mass change and corresponding frequency shifts ( △f ) of the QCM. The outer avidin-coated Au nanoparticles could combine with the target DNA to increase the mass. The electro- chemical techniques, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were adopted to manifest and character each step. The target DNA corresponding to 2.0×103 colony forming unit (CFU)/mL E. coli O157:H7 cells can be detected by this biosensor, so it is practical to develop a sensitive and effective QCM biosensor for pathogenic bacteria detection based on specific DNA analy- sis. The piezoelectric biosensing system has potential for further applications, such as food safety and environment monitoring, and this approach lays the groundwork for incorporating the method into an integrated system for in-field bacteria detection.
基金Supported by the National Natural Science Foundation of China (Grant No. 50373036)Fok Ying Tung Education Foundation (Grant No. J20040212)
文摘The synthesis of norvancomycin (NVan)-capped silver nanoparticles (Ag@NVan) and their notable in vitro antibacterial activities against E. coli, a Gram-negative bacterial strain (GNB), are reported here. Mercaptoacetic acid-stabilized spherical silver nanoparticles with a diameter of 16±4 nm are prepared by a simple chemical reaction. The formation process of the silver nanoparticles is investigated by UV-visible (UV-vis) spectroscopy and transmission electron microscopy (TEM). NVan is then grafted to the terminal carboxyl of the mercaptoacetic acid in the presence of N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDAC). The TEM images of single bacteria treated with Ag@NVan show that plenty of Ag@NVan aggregate in the cell wall of E. coli. A possible antibacterial mechanism is proposed that silver nanoparticles may help destroy the stability of the outer membrane of E. coli, which makes NVan easier to bind to the nether part of the peptidoglycan structure. The antibacterial activities of silver nanoparticles on their own, together with the rigid polyvalent interaction between Ag@NVan and cell wall, enables Ag@NVan to be an effective inhibitor of GNB. This kind of bionanocomposites might be used as novel bactericidal materials and we also provide an effective synthesis method for preparing functional bioconjugated nanoparticles here.
