Efficient drug delivery to alveolar macrophages and lung epithelial lining fluid following pulmonary administration of liposomal ciprofloxacin in rats with pneumonia and estimation of its antibacterial effects

The efficacy of pulmonary administration of liposomal ciprofloxacin (CPFX) in pneumonia was evaluated. In brief, the pharmacokinetics following pulmonary administration of liposomal CPFX (particle size, 1,000 nm; dose, 200 microg/kg) were examined in rats with lipopolysaccharide-induced pneumonia as an experimental pneumonia model. Furthermore, the antibacterial effects of liposomal CPFX against the pneumonic causative organisms were estimated by pharmacokinetic/pharmacodynamic (PK/PD) analysis. The time-courses of the concentration of CPFX in alveolar macrophages (AMs) and lung epithelial lining fluid (ELF) following pulmonary administration of liposomal CPFX to rats with pneumonia were markedly higher than that following the administration of free CPFX (200 microg/kg). The time course of the concentrations of CPFX in plasma following pulmonary administration of liposomal CPFX was markedly lower than that in AMs and ELF. These results indicate that pulmonary administration of liposomal CPFX was more effective in delivering CPFX to AMs and ELF compared with free CPFX, and it avoids distribution of CPFX to the blood. According to PK/PD analysis, the liposomal CPFX exhibited potent antibacterial effects against the causative organisms of pneumonia. This study indicates that pulmonary administration of CPFX could be an effective technique for the treatment of pneumonia.     

Thickness dependence of mobility of pentacene planar bottom-contact organic thin-film transistors

We have fabricated planar bottom-contact organic thin-film transistors as a function of the thickness of the pentacene active layer. The highest mobility of the planar bottom-contact transistors is 0.47 cm²/Vs with only a 7 nm pentacene active layer. Our planar bottom-contact transistors show much higher mobility than conventional bottom-contact counterparts and even higher than the reported mobility values of top-contact counterparts for each thickness in the range from 2.5 to 10 nm. We find that spike at the edges of source and drain electrodes seriously deteriorates device performance.     

Characteristics of organic inverters using vertical- and lateral-type organic transistors

The characteristics of vertical-type organic static induction transistors (OSITs) were compared with those of lateral-type organic field effect transistors (OFETs). From these experiments, it was confirmed that the OSITs can operate at a voltage one order less than that required for OFETs. We also fabricated two types of organic inverter based on OSITs and OFETs and investigated their transfer characteristics. These results demonstrate that it is possible to decrease the operational voltage of organic inverters from ± 20 V to ± 2 V by using two OSITs with higher on/off ratios.     

Optimum structure of metal oxide under-layer used in Ag-based multilayer

The effects of a metal oxide under-layer on the resistivity of a Ag layer were investigated. Ag-based multilayers, which have a layer construction of glass/ZnO under-layer/Ag/ZAO (Al-doped ZnO) blocker/ZnO top layer, were deposited by DC magnetron sputtering with changing the sputter gas pressure during the under-layer deposition and it was confirmed that the Ag layer showed low resistivity when the smooth crystallized ZnO under-layer was employed. On the other hand, in the case of the Ag-based multilayer using the smooth amorphous-SnO₂ under-layer, it was found that the Ag layer was poorly crystallized and showed higher resistivity than the Ag layer using the ZnO under-layer. This comparative study indicated that the ZnO under-layer promoted the preferred crystal growth of the Ag layer.     

厦门市“空心村”治理中的利益主体行动机制研究

以制度分析为研究视角,引入"制度变迁理论",对厦门市"空心村"形成背后的制度变迁特征进行了梳理,系统分析制度变迁过程中"空心村"治理的多方利益主体的行动机制,并对影响农村建设行动及治理效果的深层根源展开了讨论,尝试提出了促使"空心村"治理的相关利益主体更具备治理行动能力的制度安排和治理改造模式,并为我国乡村规划的制度分析框架的建构提供借鉴。     

Focusing of radially and azimuthally polarized beams through a uniaxial crystal

We calculated and measured the difference between focal positions of radially and azimuthally polarized beams after passing through a uniaxial crystal. Calculations were carried out on the basis of the ray optics and the vector diffraction theory. The results of the calculations were in good agreement with those of the experiment. In addition, we discussed the polarization selection in a hemispherical laser cavity that was used for the generation of a radially polarized beam by use of the birefringence of a c-cut Nd:YVO4 laser crystal [Opt. Lett. 31, 2151 (2006)]. The stability range of the laser cavity length for the generation of a radially polarized beam was also in good agreement with the differences mentioned above.     

Thermochromism in an organic crystal based on the coexistence of sigma- and pi-dimers

Transition-metal complexes and organic radical molecules can be used to make electric conductors and ferromagnets, the optical properties of which can be controlled by changing temperature and are used as molecular switches and sensors. Whereas a number of organic radicals in solution show temperature-dependent optical properties, such behaviour in crystalline forms is more rare. Here, we show a fully reversible continuous thermochromism with a unique mechanism in purely organic crystals of diazaphenalenyl radical. This behaviour is based on changes in the diazaphenalenyl dimers coexisting in the crystal. From the X-ray crystal structure analyses and temperature-dependent visible spectra, we conclude the presence of a thermal equilibrium between sigma-bonded and pi-bonded dimers, which are separated by 2.62(6) kcal mol(-1). This conclusion is supported by room-temperature electron spin resonance spectra of the solid, which showed signals that are attributable to a thermally accessible triplet state of the pi-dimer structure. This proves the coexistence of two dimers of different bonding natures in the crystal, causing it to demonstrate thermometer-like behaviour.     

Structure Optimization of the Toxic Conformation Model of Amyloid β42 by Intramolecular Disulfide Bond Formation

Amyloid β (Aβ) oligomers play a critical role in the pathology of Alzheimer's disease. Recently, we reported that a conformation-restricted Aβ42 with an intramolecular disulfide bond through cysteine residues at positions 17/28 formed stable oligomers with potent cytotoxicity. To further optimize this compound as a toxic conformer model, we synthesized three analogues with a combination of cysteine and homocysteine at positions 17/28. The analogues with Cys-Cys, Cys-homoCys, or homoCys-Cys, but not the homoCys-homoCys analogue, exhibited potent cytotoxicity against SH-SY5Y and THP-1 cells even at 10 nM. In contrast, the cytotoxicity of conformation-restricted analogues at positions 16/29 or 18/27 was significantly weaker than that of wild-type Aβ42. Furthermore, thioflavin-T assay, non-denaturing gel electrophoresis, and morphological studies suggested that the majority of these conformation-restricted analogues exists in an oligomeric state in cell culture medium, indicating that the toxic conformation of Aβ42, rather than the oligomeric state, is essential to induce cytotoxicity.     

Anisotropic property of material arrangement in friction stir welding of dissimilar Mg alloys

Microstructure and mechanical properties of friction stir weld joints of dissimilar Mg alloys AZ31 and AZ80 were investigated in the present work. Several different welding parameters were adopted in the study, and the effects of rotation speed and welding speed on the joint quality were discussed comprehensively. In addition, material arrangement which means that AZ31 alloy was at advancing side or at retreating side has significant influence on the joint formation, including the joint microstructure and mechanical properties. A few kinds of defects were observed when the improper parameters were taken in the experiment, and the reasons for generating these defects were revealed in this work. Sound joints with good mechanical properties could be easily obtained when AZ31 was at retreating side, but it was difficult to obtain the sound joint with the contrary material arrangement. These results suggest that the material with inferior plastic deformability should be set at the advancing side and the material with superior one should be set at the retreating side in order to get sound FSW joint of dissimilar Mg alloys.     

Crystal structure of GdNi3 with superlattice alloy and its hydrogen absorption–desorption property

We synthesized the intermetallic compound GdNi₃, which has a PuNi₃-type structure (space group R-3m), and investigated its P–C isotherm. The refined lattice parameters were a = 0.4993(1) nm and c = 2.4536(4) nm. In the first absorption process, two plateaus were observed, and the maximum hydrogen capacity reached 1.07 H/M. In the first desorption process, a narrow and sloping plateau was observed at approximately 0.02 MPa. After the first full desorption, 0.6 H/M of hydrogen remained in the sample. This sample showed severe peak broadening in the XRD pattern, indicating that the metal sublattice deformed from the original alloy. No plateau region was observed in the second absorption–desorption cycle.