Preparation of carboxylate group-containing rod-like polysilsesquioxane with hexagonally stacked structure by sol–gel reaction of 2-cyanoethyltriethoxysilane

Carboxylate group-containing rod-like polysilsesquioxane (PSQ-COO^?Na⁺) with a hexagonally stacked structure was successfully prepared by the sol–gel reaction (hydrolytic polycondensation) of 2-cyanoethyltriethoxysilane (CETEOS) monomer in sodium hydroxide aqueous solution. The X-ray diffraction pattern of the cast film of PSQ-COO^?Na⁺ showed three diffraction peaks with the d-value ratio of 1 : 1/√3 : 1/2, indicating the formation of hexagonal phase. In addition, the transmission electron microscopic image of PSQ-COO^?Na⁺ showed a stripe pattern, indicating that the rod-like PSQs were stacked parallel. Self-organization of an ion pair composed of a carboxylate anion and a sodium cation, which was converted from the cyano group of CETEOS by hydrolysis under alkaline conditions, was a driving force for the formation of such regular higher-ordered structures of PSQ-COO^?Na⁺.     

Electrodeposition of platinum and silver into chemically-modified microporous silicon electrodes

ABSTRACT: Electrodeposition of platinum and silver into hydrophobic and hydrophilic microporous silicon layers was investigated using chemically-modified microporous silicon electrodes. Hydrophobic microporous silicon enhanced the electrodeposition of platinum in the porous layer. Meanwhile hydrophilic one showed that platinum was hardly deposited within the porous layer and a filmy growth of platinum on the top of the porous layer was observed. On the other hand, the electrodeposition of silver showed similar deposition behavior between these two chemically-modified electrodes. It was also found that the electrodeposition of silver started at the pore opening and grew toward the pore bottom, while a uniform deposition from the pore bottom was observed in platinum electrodeposition. These electrodeposition behaviors are explained on the basis of the both effect, the difference in overpotential for metal deposition on silicon and on the deposited metal, and displacement deposition rate of metal.     

Influence of particle size on the distributions of liposomes to atherosclerotic lesions in mice

In order to confirm the efficacy of liposomes as a drug carrier for atherosclerotic therapy, the influence of particle size on the distribution of liposomes to atherosclerotic lesions in mice was investigated. In brief, liposomes of three different particle sizes (500, 200, and 70 nm) were prepared, and the uptake of liposomes by the macrophages and foam cells in vitro and the biodistributions of liposomes administered intravenously to atherogenic mice in vivo were examined. The uptake by the macrophages and foam cells increased with the increase in particle size. Although the elimination rate from the blood circulation and the hepatic and splenic distribution increased with the increase in particle size in atherogenic mice, the aortic distribution was independent of the particle size. The aortic distribution of 200 nm liposomes was the highest in comparison with the other sizes. Surprisingly, the aortic distribution of liposomes in vivo did not correspond with the uptake by macrophages and foam cells in vitro. These results suggest that there is an optimal size for the distribution of liposomes to atherosclerotic lesions.     

A combined environmental straining specimen holder for high-voltage electron microscopy

A novel specimen holder that enables in situ observation of crack-tip deformation and/or fracture under a controlled environment is developed for a high-voltage electron microscope (HVEM). A window-type environmental cell (EC) that incorporates a uniaxial straining apparatus is built into a side-entry-type single-tilt specimen holder. The gas control in EC, straining apparatus design, limited field of view for crack-tip observation, and specimen preparation for the specimen holder are presented in detail. Experimental results successfully demonstrate that the developed specimen holder is quite useful for the dynamic observation of crack-tip deformation and/or fracture subjected to a hostile environment, such as hydrogen gas.     

Highly hydrogen permeable Nb–Ti–Co hypereutectic alloys containing much primary bcc-(Nb,Ti) phase

In order to develop alloys combing high hydrogen permeability with large resistance to the hydrogen embrittlement, microstructures and hydrogen permeability (Φ) have been investigated for the as-cast alloys on the straight line connecting the eutectic {TiCo + (Nb, Ti)} phase and the Nb-rich primary (Nb, Ti) phase in the Nb–Ti–Co system. The alloys on the above-mentioned line consist of the TiCo compound and the (Nb, Ti) solid solution. The value of Φ increases with increasing temperature and volume fraction of the primary (Nb, Ti) phase. The most Nb-rich Nb₆₀Ti₂₁Co₁₉ alloy shows the highest Φ value of 3.99 × 10⁻⁸ (mol H₂m⁻¹ s⁻¹ Pa^−0.5) at 673 K, which is 2.6 times higher than that of pure Pd. The present work demonstrates that highly hydrogen permeable alloys are obtainable in the Nb rich Nb–Ti–Co ones on the straight line connecting the eutectic {TiCo + (Nb, Ti)} phase and the Nb-rich primary (Nb, Ti) phase.     

Glancing angle deposition of copper iodide nanocrystals for efficient organic photovoltaics

We report a simple method to achieve efficient nanostructured organic photovoltaics via patterning copper iodide (CuI) nanocrystals on indium tin oxide by glancing angle deposition. The strong interfacial interaction between zinc phthalocyanine (ZnPc) and CuI leads to the formation of nanopillar arrays with lying-down molecular order, which greatly improve light absorption and surface roughness for exciton dissociation. Optimized ZnPc/C(60) bilayer cell has a power conversion efficiency of 4.0 ± 0.1%, which is about 3-fold larger than that of conventional planar cell.     

Ring Size‐Selective Ring‐Closing Olefin Metathesis: Taking Advantage of the Deleterious Effect of Ethylene Gas

The deleterious effect of ethylene gas on the ring‐closing olefin metathesis (RCM) for the formation of 5‐ to 8‐membered rings was investigated. Significant rate differences caused by ethylene gas were observed among the different ring‐size formation reactions. Nevertheless, the rate differences can be advantageously utilized for chemoselective RCM.     

Identification of Physiological and Toxic Conformations in Aβ42 Aggregates

Aggregation of the 42‐residue amyloid β‐protein (Aβ42) plays a crucial role in the pathogenesis of Alzheimer's disease (AD). Despite numerous structural studies on Aβ aggregates, the relationship between tertiary structure and toxicity remains unclear. Our proline scanning and solid‐state NMR studies suggested that aggregates both of wild‐type Aβ42 and of E22K‐Aβ42 (one of the mutants related to cerebral amyloid angiopathy) contain two conformers: a major one with a turn at positions 25 and 26, and a minor one with a turn at positions 22 and 23. To identify the toxic conformer, the derivative Aβ42‐lactam(22K–23E), in which the side chains at positions 22 and 23 were covalently linked, was synthesized as a minor conformer surrogate, along with Aβ42‐lactam(25K–26E) as a major conformer surrogate. The Aβ42‐lactam(22K–23E) showed stronger aggregation, neurotoxicity, radical generation, and oligomerization than wild‐type Aβ42, whereas in Aβ42‐lactam(25K–26E) were weak. The transition from the physiological conformation with a turn at positions 25 and 26 to the toxic conformation with a turn at positions 22 and 23 might be a key event in the pathogenesis of AD.     

Comparison of Foliar Spray Efficacy of Electrolytically Ozonated Water and Acidic Electrolyzed Oxidizing Water for Controlling Powdery Mildew Infection on Cucumber Leaves

We investigated and compared the effects of foliar sprays of electrolytically ozonated water (OW) and acidic electrolyzed oxidizing water (AEOW) on severity of powdery mildew infection (PMI) and occurrence of visible physiological disorder on cucumber leaves. Foliar spray of OW contained severity of PMI to almost the same level as the initial value, without any visible physiological disorder. Although severity of PMI on AEOW-sprayed leaves was significantly lower than on OW-sprayed leaves, the leaves showed a visible physiological disorder after the first spray. These results indicate that OW is a viable option for controlling PMI on cucumber leaves at low initial severity levels, or for prevention of PMI, and that AEOW can be used for controlling PMI with special efforts taken against a visible physiological disorder.