中国人CD59cDNA克隆、序列分析及其表达

用ＲＴ－ＰＣＲ方法从中国人胚胎总ｍＲＮＡ中扩增出４２０ｂｐ人补体终末阶段同源限制因子（ＣＤ５９）的ｃＤＮＡ，序列分析结果表明，所获得的ＣＤ５９ｃＤＮＡ与文献报道中的基因序列完全一致，含ＣＤ５９全长编码区．构建了真核表达质粒，在３Ｔ３细胞中得到了表达．     

Weak solutions of the interior boundary value problems of plane Cosserat elasticity

In this paper we formulate interior Dirichlet and Neumann boundary value problems of plane Cosserat elasticity in Sobolev spaces, show that these problems are well-posed and find the corresponding weak solutions in the form of integral potentials. Received: April 7, 2005     

Molecular dynamics simulation study on the interaction of KRN 7000 and three analogues with human CD1d

Many analogues of KRN 7000, a synthetic glycolipid (α-galactosylceramide) exhibiting immuno-stimulatory activity and antitumor properties, were previously synthesized and tested in order to understand the reasons for the resulting biological activity and Th1/Th2 cytokine profile. Principles have been established for the interaction of such glycolipids with the human CD1d molecule but the exact mechanism by which different ligands with the same polar head elicit distinct biological responses remains unclear. Based on these experiments and on the available crystal structures, protein-ligand interactions are explored using molecular dynamics simulations. Hydrogen bond interactions are examined with regard to the polar group orientation. The influence of modulations on the dynamic behavior of the CD1d-glycolipid complex is addressed. Overall, our data support the mechanism by which the shortening of the α-GalCer sphingosine chain causes a significant twist of the CD1d α1 helix structure from residue Phe84 that affects the position of CD1d residues involved in the TCR recognition.     

Superconducting properties of rapidly quenched and heat treated Zr-V and Hf-V foils

The results of rapid quenching and subsequent heat treatments on the superconducting properties of the Zr-V and Hf-V binary systems are presented. Metallic glasses can be prepared in these systems which have very attractive properties for practical application. The existence of a flexible glassy phase raises the prospect of alternative methods for the construction of superconducting devices. As-quenched, partially crystalline material is characterized by small critical currents, yet relatively large upper critical fields and transition temperatures. Heat treatments considerably enhance the current carrying capability. Work supported by Department of Energy Contract No. DE-AC03-76ER00822.     

The contributions of amplitude-and phase-sensitive detection to the synchronous demodulation in a RF SQUID magnetometer

It is known that the tank-circuit voltage of the rf SQUID carries information about the magnetic flux to be detected in amplitude and phase. The coherent demodulationtechnique utilizes mixing circuits to shift the rf tank voltage spectrum to dc without loss of any signal-information both in amplitude and phase (AM & Pm-detection). Vice versa such a combined detection can be devided into two several detection channels, amplitude sensitive detection (AM) and phase sensitive detection (PM). The contribution of each single mode to the combined detection AM & PM is analysed theoretically in the limit of small magnetic signals and measured in special rf circuits of the magnetometer, which apply PLL-techniques. The influence of feedback is also calculated. For refined studies of the interesting parameters the reference signal of the rf mixer allows to be phase-shifted by an arbitrary amount. All three modes of detections are sketched in diagrams as magnetometeroutput versus phase-shift of that reference signal. In addition, noise analysis is included and measured for vanishing signal. Basic formulas are derived for signal-to-noise ratios. A correlation coefficient is defined for recording correlated noise sources between AM and PM, whereby the possibility of S/N-improvement is pointed out. By computer support the graphs of equations are fitted to measured data with least mean-square deviation. More logical than functional circuit diagrams complete the insight into the treated basic ideas.     

Iron metabolism in the mononuclear phagocyte system

The maintenance of body iron homeostasis requires the coordination of multiple regulatory mechanisms of iron metabolism. The mononuclear phagocyte system （MPS, composed of monocytes, macrophages, and their precursor cells） is crucial in the maintenance of iron homeostasis. Recycling of iron is carried out by specialized macrophages via engulfment of aged erythrocytes. The iron stores of macrophages depend on the levels of recovered and exported iron. However, the molecular mechanisms underlying iron homeostasis in macrophages are poorly understood. Recent studies characterizing the function and regulation of natural resistance-associated mac- rophage protein 1 （Nrampl）, divalent metal transporter 1 （DMT1）, HLA-linked hemechromatosis gene （HFE）, ferroportin 1 （FPN1）, and hepcidin are rapidly expanding our knowledge on the molecular level of MPS iron handling. These studies are deepening our under- standing about the molecular mechanism of iron homeostasis and iron-related diseases.     

Direct assignment of enantiofacial discrimination on single heterocyclic substrates by self-induced CD

The first direct assignment of highly dynamic enantiofacial discrimination acting on a single heterocyclic substrate has been achieved by a combination of experimental and theoretical CD spectroscopy. The interaction of chirally modified hosts based on triphenylene ketals with appropriate prochiral guests can lead to the preferential formation of one diastereomeric host-guest complex. This reversible stereoselective binding transmits the chiral information from remote chiral groups in the host to the strongly absorbing triphenylene chromophore, which gives rise to self-induced CD. This effect was exploited for the determination of the enantiofacial recognition in various host-guest systems. Inversion of the steric demand either of the chiral substituents at the host or of the prochiral guest leads to almost complete inversion of the resulting CD spectra. For the assignment of the absolute stereochemistry of the complexes, a combined molecular dynamics/quantum-chemical approach was successfully employed. Despite the size and the highly dynamic character of the supramolecular systems, fundamental properties of the systems and details of the spectra were simulated accurately, providing access to fast and reliable assignment of the enantiofacial preference. The results are highly consistent with available X-ray data.     

浅谈基于汇文系统Libsys4.0的期刊验收典藏工

介绍了"汇文系统Libsys4.0"中期刊验收典藏功能,对期刊的批量验收典藏、单刊典藏、光盘典藏以及常用参数设置进行了较为详细的说明,指出了期刊验收典藏工作中应注意的问题。     

Spectrophotometric studies on the interaction between myricetin and lysozyme in the absence or presence of Cuor Fe

The binding of myricetin to lysozyme (Lys) in aqueous solution was investigated by fluorescence spectroscopy, ultraviolet-visible absorption spectroscopy (UV) and circular dichroism (CD) spectra under physiological conditions. There are also many metal ions present in body, thus the research about the effect of metal ions on the interaction of drugs with proteins is crucial. In this study, we have investigated the effect of both familiar metal ions Cu²⁺ and Fe³⁺ on the interaction between myricetin and Lys by using spectroscopy technique at pH 7.40, for the first time. Spectrophotometric observations are rationalized in terms of a static quenching process in a static quenching way. The cause of showing upward curvy patterns in Stern-Volmer plots was analyzed. The binding constants and binding sites of myricetin with Lys with or without Cu²⁺ and Fe³⁺ at different concentrations of myricetin were calculated. UV/vis measurements on the enzymatic activity of Lys with or without Cu²⁺ in the absence or presence of myricetin indicated that the interaction between myricetin and Lys led to a reduction in the activity of Lys. Furthermore, the effect of pH on the binding constant of myricetin with Lys was also examined.