鞘磷脂和神经节苷脂对磷脂酰乙醇胺混合脂超分子体系液晶态立方相Im3m和Pn3m结构影响的研究

用磷脂酰乙醇胺(DEPE)、鞘磷脂(Sphingomyeline, Sph)、神经节苷脂(Gm1)和胆固醇(Chol)模拟了生物膜超分子体系液晶态结构, 通过用小角X射线衍射(SAXD)对混合脂体系液晶态结构进行了研究, 鉴定出了两种立方相: 即Im3m(Q²²⁹)和Pn3m(Q²²⁴)结构. 实验发现, 鞘磷脂的含量对DEPE膜的结构有一定的影响, 随着鞘磷脂浓度的增加, 混合脂体系的液晶态结构发生了由Im3m(Q²²⁹)到Pn3m(Q²²⁴)的变化. 神经节苷脂(Gm1)的含量对混合脂体系的液晶态结构也有一定的影响, 当神经节苷脂(Gm1)含量达到某一临界值时, 混合脂体系的液晶态结构发生了从Im3m(Q²²⁹)到Pn3m(Q²²⁴) 的变化. 当DEPE-Shp-Gm1超分子聚集体中含有胆固醇时, 胆固醇的极性头部(—OH)与磷脂酰乙醇胺(DEPE)、鞘磷脂(Shp)、神经节苷脂(Gm1)的极性头部通过氢键相互作用形成液晶态立方相Im3m(Q²²⁹)结构, 再通过疏水/亲水相互作用形成稳定的Pn3m (Q²²⁴)结构.     

高效液相色谱-荧光检测法测定敬钊毒素-I的磷脂膜结合活性

敬钊毒素-I(JZTX-I)是一种能够抑制心肌钠通道失活的新型蜘蛛神经毒素,该文结合高效液相色谱与色氨酸荧光测定技术研究了JZTX-I的磷脂膜结合活性。脂质体共沉淀实验表明,JZTX-I具有不依赖于带负电荷磷脂组成的生物膜结合活性。当加入由酸性或中性磷脂构成的脂质体后,JZTX-I能够分别产生6.4和4.7 nm的蓝移以及7.4和8.0 nm的红移激发漂移,显示JZTX-I能够插入磷脂膜,同时该分子疏水表面的色氨酸残基处于一个运动受限的界面区域。荧光淬灭实验进一步证实,与脂质体结合能够减少该毒素分子表面色氨酸残基的溶剂暴露。该研究结果为阐明JZTX-I的离子通道门控调节机制提供了新的信息。     

Phanes with Three- and Four-Membered Rings as Building Elements

The systematic integration of the small 2π- and 4π-electron systems cyclopropenylium ion, cyclopropenone, oxo-cyclobutenylium ion, and cyclobutadiene into phane chemistry was initiated only a few years ago. [n₂]Cyclopropenylophanes, [n₂]cyclopropenonophanes, metal-capped [n₄]cyclobutadienosuperphanes, and other new families of double-decker phane species became available from cycloalkydiynes through special methods of double [2+1]cycloaddition with carbenes and metal complex induced dimerization by double [2+2]cycloaddition. Phane-specific structural features were elucidated by X-ray structural analyses. Cyclic voltammetry and PE spectroscopy as well as MO calculations reealed considerable interactions between closely spaced π-electron systems. Decapping cyclobutadienosuperphanes formally extended the synthetic principle to threefold [2+2]cycloadditions resulting in [n₄]-bridged tricyclo-[4.2.0.0^{3, 5}]octa-3,7-dienes, which represent a new type of cage compounds. Moreover, completion to fourfold [2+2]addition was achieved with the photoinduced transformation of [3₄]bridged tricyclo[4.2.0.0^{3, 5}]octa-3,7-diene into propella[3₄]cubane.     

极性和非极性溶剂在聚乙烯中的无限稀释扩散系数的测定

 气相法研究小分子溶剂与高分子聚合物材料之间的相互作用是一个快速、准确、方便的方法 ,可以测量多种小分子溶剂在聚合物中的溶解、扩散参数。通过气相法测定了 5种小分子溶剂 (正己烷、正庚烷、正癸烷、乙醇和水 )在固定液聚乙烯中的保留时间和半峰宽 ,运用vanDeemter模型进行数据处理 ,得到上述 5种小分子在聚乙烯中的无限稀释扩散系数 ,获得了十分有意义的结果。     

有机小分子催化的不对称羟醛缩合反应

总结了近年来用于不对称催化羟醛缩合反应的各种有机小分子催化剂, 简要阐述了每种类型的催化剂的催化机理以及它们的优缺点, 同时对有机小分子催化反应的发展进行了展望.     

Characteristic lengths and the structure of salt free polyelectrolyte solutions. A small angle neutron scattering study

We have studied salt free semi dilute polyelectrolyte solutions by small angle neutron scattering. Specific labelling associated with an extrapolation method has allowed the separation of the form factor of a single polyelectrolyte chainS ₁(q) and the structure factorS ₂(q). Two lengths are deduced from these two factors: the persistence lengthb _t which characterizes the electrostatic interactions along the chain by a fitting ofS ₁(q) with calculation of the scattering function for a wormlike chain, and fromS ₂(q),q _m ^–1 which characterizes the interactions between chains. These two lengths vary in the same way with the concentration of polyions (b _t C _p ^–1/2 ,q _m ^–1 C _p ^–1/2 ) and a constant relation exists between them: only one length is then necessary to describe the structure of polyelectrolyte soltuion on this semidilute concentration range.Laboratoire Commun CEA-CNRS.     

中小企业信息化系统建设及综合应用

本文介绍了中小企业信息化系统的建设的相关网络技术，简述了信息化系统的综合应用。     

Power optimization using optimal small cell arrangements in different deployment scenarios

For smooth transition from 4G to 5G, there is a need for optimizing the power in the wireless communication. In 5G, it is expected that the number of users will increase drastically that correspondingly increase the utilization of power in the transmitter and receiver sides. So researchers and academicians are now finding ways to optimize the power. Some optimizing methods like convex optimization are very helpful for optimized algorithm design. In this paper, a proposed mathematical approach for deployment of small cell access point is used for optimizing the power consumption in the massive multiple input and multiple output and small cell scenario. The new proposed mathematical approach will also help in deciding the optimal number of small cell access points and optimal location of these small cell access points for the particular deployment scenario like urban macro heterogeneous deployment scenario in the 3GPP LTE standard and different macro deployment scenario in the ITU‐R M.2135 standard like urban macro, suburban macro, and rural macro, for optimizing the power.     

Real-time sensing and three-dimensional display of far outdoor scenes based on asymmetric integral imaging

A new asymmetric integral imaging (AII) system for real-time pickup and three-dimensional (3-D) display of far outdoor scenes based on dynamic-pixel-mapping (DPM) is proposed. DPM is a digital process to transform the elemental images captured with a lens array into the perspective-variant object images (POIs) whose structures are matched with those of display lenses, where the orders of pixels in each POI are reversely mapped, and then capture a set of virtual elemental images (EIs) at the specific depth planes from the back-propagated POIs. This DPM enables an asymmetrical use of pickup and display lens arrays, allowing the long-ranged pickup of far outdoor scenes and their resolution-enhanced 3-D reconstruction. Experiments with a pair of pickup and display lens arrays whose pitches and focal lengths are given by 7.5 mm, 30 mm and 1.2 mm, 8 mm, respectively, show that the effective pickup-range and resolution of the proposed system have been increased up to 6 m and 1600×1600 pixels, respectively, from 0.064 m and 480×480 pixels of the conventional systems employing the same pickup and display lens arrays. In addition, experiments with an implemented test bed confirms that the proposed system can provide real-time 3-D images in 25 frames per second.     

Conductivity anomalies in Y–Ba–Cu–O at 40K and 100K under high quasihydrostatic pressures

Electrical resistance measurements at low temperatures and high quasihydrostatic pressures on superconducting and non-superconducting varieties of Y_0.8Ba_1.2Cu₂O₅ (obtained by annealing in oxygen and air respectively) show striking anomalies in the vicinity of 100K and 40K. Arguments are presented to show that these anomalies as also the occurrence of T 's in the oxide superconductors either in the vicinity of 100K or of 40K are connected with their layered structure containing planes of Cu-O otahedral complexes.