Laser-based transfection with conjugated gold nanoparticles

The irradiation of ceils combined with the immunoconjugate of gold nanoparticles by the short pulse laser can make the plasma membrane be transiently permeabilized, which can be used to transfer exogenous molecules into the cells. We explore this technique as a novel gene transfection method for floating cells. Three different floating cells exposed to the laser are selectively transfected with fluorescein isothiocyanatedextran, antibody, and green fluorescent protein （GFP） coding plasmids, and the viability of cells are determined by propidium iodide. For fluorescein isothiocyanate-dextran, the best transfection efficiency of 65% is obtained; for the antibody, it is 74%; whereas for the green fluorescent protein coding plasmids, a very small transfection efficiency is gained. If the transfection efficiency is improved, gold nanoparticles will be very useful as mediator for gene transfection in living cells.     

K3C60取向相变的同步辐射光电子谱研究

在190K,220K和300K3个不同温度下测量了K₃C₆₀单晶薄膜沿[111]方向发射的同步辐射角分辨光电子谱.样品温度为190K时,能够观察到导带有规律的角散,并且带结构与已报道的温度为150K时的结果基本一样.而在220K附近,导带的许多子峰消失,色散不再存在.这两个温度的实验结果与K₃C₆₀在200K存在取向相变相符合,并且可在反铁磁Ising模型基础上得到理解.这种模型的定量分析结果还首次对K₃C₆₀在200K的相变机理作出了解释,即相变是由低温下的一维无序取向结构转变为200K以上的双取向结构畴与无序分子(约占40%)的混合.室温光电子谱与低温下的结果显著不同,对应于C₆₀分子取向在室温附近的动态无序.     

电磁干扰对策元件简介(5)

<正> 抗电磁干扰连接器和继电器 导体传导是电磁干扰的主要传播途径。连接器是系统与系统、系统与子系统以及各子系统之间的导体连接部位,所以连接器是抑制电磁干扰的重要环节。在电磁兼容浪潮的推动下,出现了一些抗电磁干扰的连接器和继电器。     

心脏组织的自体荧光研究

测量并研究了家兔心脏组织自体荧光的三维光谱和发射光谱。果表明：冰冻前后心室和心房组织的三维荧光光谱差异较主动脉明显,说明冰冻后其NADH和黄素的含量改变。心房、心室和主动脉组织在340 nm激发光下的自体荧光光谱具有特定的差异,其主要荧光峰位于460 nm 的NADH,以及290～400 nm之间的胶原蛋白和弹性蛋白。根据心房和心室组织的高斯拟和光谱发现,光谱的峰位、相对荧光强度和半宽等参数各不相同。由此,可以根据荧光光谱的谱形和峰强比可以显著区分出不同的心脏组织类型。此外,研究首次发现心室组织NADH的荧光强度会随心肌死亡时间增加而衰减,可作为死亡时间确定的新方法。     

复合结构组织工程化人工骨的金属支架结构设计研究?

支架结构设计是组织工程化人工骨设计的重要内容之一,本文对金属与陶瓷材料构成的复合结构人工骨中金属支架的设计进行了研究。通过对髋关节置换后假体与股骨之间力的传递规律进行数值模拟研究,采用分截面分析、网格密度逐渐减小的设计方法,对复合结构人工骨中的金属支架结构进行了设计。通过对6种不同网格密度金属支架的受力情况进行对比分析,设计出了力学特性符合股骨受力规律的金属支架结构。     

Detection of Fe 3d electronic states in valence band and magnetic properties of Fe-doped ZnO film

Fe-doped ZnO film has been grown by laser molecular beam epitaxy (L-MBE) and structurally characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), all of which reveal the high quality of the film. No secondary phase was detected. Resonant photoemission spectroscopy (RPES) with photon energies around the Fe 2p-3d absorption edge is performed to detect the electronic structure in the valence band. A strong resonant effect at a photon energy of 710 eV is observed. Fe³⁺ is the only valence state of Fe ions in the film and the Fe 3d electronic states are concentrated at binding energies of about 3.8 eV and 7 eV～ 8 eV. There are no electronic states related to Fe near the Fermi level. Magnetic measurements reveal a typical superparamagnetic property at room temperature. The absence of electronic states related to Fe near the Fermi level and the high quality of the film, with few defects, provide little support to ferromagnetism.     

SiH2Cl2-NH3配比对a-SiNx:H薄膜PL峰的影响

低压化学气相沉积制备的纳米硅镶嵌结构的a-SiNx：H薄膜,在3．75eV的激光激发下,室温下发射1～3个高强度的可见荧光。在相同的沉积温度下（900℃）,选择不同的SiH2Cl2和NH3气体配比时,所得薄膜表现出不同的荧光属性,荧光峰的峰位和数目有着显著的变化。通过TEM、IR、XPS等分析手段对其原因进行了研究分析,认为不同配比下,生成的薄膜中缺陷态的种类和密度有所不同,这影响了其PL峰个数及其各峰的相对强弱。     

Observation of selective surface element substitution in FeTe_(0.5)Se_(0.5) superconductor thin film exposed to ambient air by synchrotron radiation spectroscopy

A systematic investigation of oxidation on a superconductive Fe Te_(0.5)Se_(0.5)thin film,which was grown on Nb-doped SrTiO_3(001) by pulsed laser deposition,has been carried out.The sample was exposed to ambient air for one month for oxidation.Macroscopically,the exposed specimen lost its superconductivity due to oxidation.The specimen was subjected to in situ synchrotron radiation photoelectron spectroscopy(PES) and x-ray absorption spectroscopy(XAS) measurements following cycles of annealing and argon ion etching treatments to unravel what happened in the electronic structure and composition after exposure to air.By the spectroscopic measurements,we found that the as-grown FeTe_(0.5)Se_(0.5)superconductive thin film experienced an element selective substitution reaction.The oxidation preferentially proceeds through pumping out the Te and forming Fe–O bonds by O substitution of Te.In addition,our results certify that in situ vacuum annealing and low-energy argon ion etching methods combined with spectroscopy are suitable for depth element and valence analysis of layered structure superconductor materials.     

基于ALA的PDT体外灭活HL60实验研究

利用自行设计的光动力疗法(PDT)反应室对HL60细胞进行了氨乙酰丙酸(ALA)PDT实验研究，获得灭活HL60细胞的最佳光学参量因子：ALA培养的终浓度为1．0mM／ml；ALA的培养时间为4h；辐射光波长为412nm；辐照光剂量为18J／cm^2；辐照光功率为5mW／cm^2；培养细胞的胎牛血清(FCS)浓度为8％～10％。在这些光学参数下对HL60的灭活能达89．9％，而单核淋巴细胞(PBMC)的损伤仅为15％，基本上能达到选择性地灭活肿瘤细胞HL60。     

一个新型、综合的表面分析装置———同步辐射光电子能谱实验站

一个新型、综合的表面分析装置———同步辐射光电子能谱实验站刘凤琴奎热西钱海杰陶小平杨易董宇辉贾金蜂（中国科学院高能物理研究所，北京１０００３９）在所有现代表面分析技术中，光电子能谱是使用最广泛的一种．光电子能谱主要研究处于表面的物质的电子结构，因而...