On The Structure Of The Chan-Paton Factors For D-Branes In Type II Orientifolds

We determine the structure of the Chan-Paton factors of the open strings ending on space filling D-branes in Type II orientifolds. Through the analysis, we obtain a rule concerning possible distribution of O-plane types. The result is applied to classify the topology of D-branes in terms of Fredholm operators and K-theory, deriving a proposal made earlier and extending it to more general cases. It is also applied to compactifications with N=1 supersymmetry in four-dimensions. We adapt and develop the language of category in this context, and use it to describe some decay channels.Comment: 137 page

Study on SiCp/6063Al composites laser welding process with Al75Cu20Ti5 foil interlayer

This experiment chooses 6063 aluminum matrix composites containing 55~75% SiC particle reinforcing phase as the parent metal and Al75Cu20Ti5 foil as the interlayer. The laser power, defocusing amounts and welding speed are discussed using three important parameters for the joint forming, microstructure and shear strength. The result shows that the weld width is mainly affected by laser power, and the weld penetration is almost determined by the defocusing amount. The welding speed has a certain influence on both weld width and weld penetration. When suitable laser heat input is adopted, superior weld appearance and satisfied shear strength could be obtained. The highest shear strength is 217MPa, with the laser power of 520W, the defocusing amounts of -1mm, and the welding speed of 1.5cm/s

Vortex and droplet in holographic D-wave superconductors

We investigate non-trivial localized solutions of the condensate in a (2+1)-dimensional D-wave holographic superconductor model in the presence of a background magnetic field. The calculation is done in the context of the (3+1)-dimensional dual gravity theory of a charged massive spin-2 field in an AdS black hole background. By using numeric techniques, we find both vortex and droplet solutions. These solutions are important for studying the full phase diagram of D-wave superconductors.Comment: 9 pages, 8 figures, several references were added, to appear in Phys. Lett.

Degradable gene delivery systems based on Pluronics-modified low-molecular-weight polyethylenimine: preparation, characterization, intracellular trafficking, and cellular distribution

Wei Fan1,2,*, Xin Wu1,*, Baoyue Ding3,*, Jing Gao4, Zhen Cai1, Wei Zhang1, Dongfeng Yin1, Xiang Wang1, Quangang Zhu1, Jiyong Liu1, Xueying Ding4, Shen Gao1 1Department of Pharmaceutics, Changhai Hospital, Second Military Medical University, Shanghai, 2Department of Pharmaceutics, The 425th Hospital of PLA, Sanya, 3Department of Pharmaceutics, Medical College of Jiaxing University, Jiaxing, 4Department of Pharmaceutics, School of Pharmacy, Second Military Medical University, Shanghai, People's Republic of China*These authors contributed equally to this workBackground: Cationic copolymers consisting of polycations linked to nonionic amphiphilic block polymers have been evaluated as nonviral gene delivery systems, and a large number of different polymers and copolymers of linear, branched, and dendrimeric architectures have been tested in terms of their suitability and efficacy for in vitro and in vivo transfection. However, the discovery of new potent materials still largely relies on empiric approaches rather than a rational design. The authors investigated the relationship between the polymers' structures and their biological performance, including DNA compaction, toxicity, transfection efficiency, and the effect of cellular uptake.Methods: This article reports the synthesis and characterization of a series of cationic copolymers obtained by grafting polyethyleneimine with nonionic amphiphilic surfactant polyether-Pluronic® consisting of hydrophilic ethylene oxide and hydrophobic propylene oxide blocks. Transgene expression, cytotoxicity, localization of plasmids, and cellular uptake of these copolymers were evaluated following in vitro transfection of HeLa cell lines with various individual components of the copolymers.Results: Pluronics can exhibit biological activity including effects on enhancing DNA cellular uptake, nuclear translocation, and gene expression. The Pluronics with a higher hydrophilic-lipophilic balance value lead to homogeneous distribution in the cytoplasm; those with a lower hydrophilic-lipophilic balance value prefer to localize in the nucleus.Conclusion: This Pluronic-polyethyleneimine system may be worth exploring as components in the cationic copolymers as the DNA or small interfering RNA/microRNA delivery system in the near future.Keywords: Pluronics, gene transfer, nonviral vectors, transfection efficiency, cellular uptak

Selective on/off switching at room temperature of a magnetic bistable {Fe2Co2} complex with single crystal-to-single crystal transformation via intramolecular electron transfer

National Nature Science Foundation of China [21172084, 20802022]; Self-determined research funds of CCNU from the colleges' basic research and operation of MOE [CCNU13F006, CCNU11C01002]A cyano-bridged {Fe2Co2} complex shows reversible single crystal-to-single crystal transformation between diamagnetic and paramagnetic states switched specifically by losing and absorbing methanol at room temperature in the solid state. And the solvent loss form presents temperature- and pressure-induced intramolecular electron transfer behaviour