Cellular internalization of proinsulin C-peptide

Proinsulin C-peptide is known to bind specifically to cell membranes and to exert intracellular effects, but whether it is internalized in target cells is unknown. In this study, using confocal microscopy and immunostained or rhodamine-labeled peptide, we show that C-peptide is internalized and localized to the cytosol of Swiss 3T3 and HEK-293 cells. In addition, transport into nuclei was found using the labeled peptide. The internalization was followed at 37°C for up to 1 h, and was reduced at 4°C and after preincubation with pertussis toxin. Hence, it is concluded to occur via an energy-dependent, pertussis toxin-sensitive mechanism and without detectable degradation within the experimental time course. Surface plasmon resonance measurements demonstrated binding of HEK-293 cell extract components to C-peptide, and subsequent elution of bound material revealed the components to be intracellular proteins. The identification of C-peptide cellular internalization, intracellular binding proteins, absence of rapid subsequent C-peptide degradation and apparent nuclear internalization support a maintained activity similar to that of an intracrine peptide hormone. Hence, the data suggest the possibility of one further C-peptide site of action. Received 31 October 2006; received after revision 27 December 2006; accepted 30 December 2006     

SrFCl:Eu~(2+)晶体的电子自旋共振谱研究

用程序降温法生长了SrFCl:Eu~(2+)晶体,并测量了它的电子自旋共振谱。应用最小二乘法拟合技术对g因子及自旋哈密顿参数进行了精确拟合。报道了各向异性的g因子及有关自旋哈密顿参量。发现并归属了Eu~(2+)的高阶禁阻跃迁。     

电视接收机图像中频的探讨

依据电视接收机图像中频选择原则，论述了我国电视接收机两次改变图像中的必要性。     

Functional magnetic resonance imaging of amphetamine craving

The aim of this study is to identify the brain activity associated with amphetamine craving for understanding the neurobiology of addiction by watching pictures of happy, sad or amphetamine. Brain activity was measured in 12 amphetamine addicts and 12 healthy subjects by fMRI while the subjects watched pictures designed to elicit happy feelings, sad feelings, or the desire to use amphetamine. The result demonstrated that amphetamine cues led to abnormally high cingulate and low frontal lobe activation in amphetamine addicts, who showed abnormalities in affect-related brain activation.     

流化床烧炭再生的动力学研究--过渡态的动力学模型

考虑内外、扩散的影响下 ,建立了烧炭再生中氧和碳在催化剂颗粒上的浓度分布方程 用单点正交配置法模拟出了焦炭转化率与反应时间的关系模型 ,并将模型计算值与实验测定值进行了比较 ,二者符合良好     

Co2+离子在CsMgCl3晶体中的g因子和超精细结构常数研究

用基团模型的3d^7离子在三角对称下的高阶微扰公式计算了CsMgCl3晶体中Co^2＋杂质中心的g因子g∥,g⊥和超精细结构常数A∥和A⊥。计算中，不仅考虑了基态和激发态间的组态相互作用效应，而且考虑了3d^7离子d轨道与配体p轨道之间的共价效应，与这两种效应相关的参数可由所研究晶体的光谱和结构数据得到。在考虑了键长与键角的微弱畸变后，理论计算值与实验观测值符合较好。     

The Primary Configuration and Formulae of the Intermediate Frequency Bend Machine

In this paper the primary configuration and formulae of design parameters of the intermediate frequency bend machine(φ1450)are introduced and the main points of its design are explained.     

两个动能耦合Morse振子系统的分岔现象

从两个未耦合的Morse振子出发,首先研究了两个动能耦合的Morse振子系统局域模区域内的分岔结构.发现对弱耦合参数δ,相空间中局域模谐振nm共存与系统能量ε通过不等式 √1/1-ε≥n/m≥√1- ε相关联.同时报导了对称伸缩本征模的分岔现象与能量及耦合常数的关系.在弱耦合参数δ下,在非常低的能量区域内,对称伸缩经历一个pitch-fork分岔.随后,局域模随能量的增加逐渐形成.对中等高能量ε,对称伸缩本征征模在耦合参数范围[-1,0]内由不稳定到稳定到不稳定等交替变化.     

The Experimental and Theoretical Research of “Local Resonance“ in Ultrasonic Honing System

In 1982, Professor Fang Guoliang found the “Non full resonance“ phenomenon in a tool system while he use the thin-long tool ultrasonically machining deep-small hole. He called it as “local resonance“. Also this “Non full resonance“ phenomenon was discovered in the ultrasonic drilling and the ultrasonic honing system later. To its mechanism, professor Fang thought that the coupling of long-thin tool bar and driving system is weak, so the tool bar can vibrate independently, but the quantitative relation betwe...     

应用核磁共振实验实现量子计算的注记

从量子力学的基本原理出发,阐述了利用核磁共振进行量子计算的实验方法,澄清了有关文献中若干容易混淆而又十分重要的概念,并进一步报道CNOT门操作的实验方法和结果.实验结果与理论的预言一致.