Fluorescent aplyronine a: intracellular accumulation and disassembly of actin cytoskeleton in tumor cells

Nonstick: Aplyronine A (ApA) is an antitumor and apoptogenic macrolide of marine origin. We prepared a fluorescent derivative of ApA that accumulated strongly throughout the cytoplasm and caused the rapid disassembly of the actin cytoskeleton in tumor cells. We also established that ApA caused malfunction of cell adhesion and dephosphorylation of focal adhesion kinase with apoptosis.     

Damage monitoring of CFRP stiffened panels under compressive load using FBG sensors

FBG sensors were embedded in each of two CFRP stiffened panels fabricated by VaRTM. Low-velocity impacts were applied to one of the panels in order to compare the methods of monitoring impact events using FBG sensors. The main impact damage was an interlaminar delamination inside the skin, which could be observed by an ultrasonic C-scan. A monitoring method using the full spectral signals was more effective in evaluating the impact damages in detail than that using the center wavelength. Following the impact tests, buckling behaviors were investigated under compressive loading using FBG sensors and surface-attached strain gauges. The FBG sensors could evaluate strain changes resulting from buckling behaviors under relatively low compressive loading. They could also evaluate damage growth until the final failure and difference of buckling behaviors between panels with and without impact damages.     

Changes in lamellar arrangement of crystalline and flexible fluorinated transparent films with drawing

In recent times, a “crystalline” and flexible optical waveguide candidate with excellent heat‐resistance and dimensional stability are developed. For the practical use of this crystalline optical film in the near future, an accurate control of the solid‐state structure is indispensable because of the necessity of reducing light refraction at the crystalline/amorphous interface. In this study, changes in the fine structure and lamella arrangement upon drawing poly[tetrafluoroethylene‐co‐(perfluoroethylvinylether)] (EFA) transparent crystalline films were investigated by using wide‐angle X‐ray diffraction (WAXD) and small‐angle X‐ray scattering (SAXS) methods. The EFA was crystallized as a lamella crystal in the films and formed a thicker lamella. Upon the drawing of the EFA films, four‐point SAXS diagrams developed in the photograph at through direction to the film, which implied that a particular type of layer structure, an alternately tilted lamella arrangement known as the herringbone, was formed. From the result of WAXD and SAXS measurements at edge direction to the film, it is found that formation of isotropic disordered lamella arrangement. Therefore, it is indicated that three‐dimensional lamella arrangement in this fluorinated transparent film forms uniaxially cylindrical symmetry. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers     

Evaluation of hydrogen atom density generated on a tungsten mesh surface

The density of hydrogen atoms supplied from hot tungsten (W) wires with a mesh structure to a tungsten phosphate glass plate substrate surface was evaluated. Variations in the hydrogen atom density were measured as a function of the mesh temperature (1000 to 1800 °C) and the exposure time (3 to 60 min). It became apparent that the quantity of H atoms supplied from hot W mesh was one order of magnitude larger than that supplied from hot W wires without a mesh structure, for the same temperature and surface area of the wire.     

Preparation of a platinum electrocatalyst by coaxial pulse arc plasma deposition

We have developed a new method of preparing Pt electrocatalysts through a dry process. By coaxial pulse arc plasma deposition (CAPD), highly ionized metal plasma can be generated from a target rod without any discharged gases, and Pt nanoparticles can be deposited on a carbon support. The small-sized Pt nanoparticles are distributed over the entire carbon surface. From transmission electron microscopy (TEM), the average size of the deposited Pt nanoparticles is estimated to be 2.5 nm, and their size distribution is narrow. Our electrocatalyst shows considerably improved catalytic activity and stability toward methanol oxidation reaction (MOR) compared with commercially available Pt catalysts such as Pt black and Pt/carbon (PtC). Inspired by its very high efficiency toward MOR, we also measured the catalytic performance for oxygen reduction reaction (ORR). Our PtC catalyst shows a better performance with half-wave potential of 0.87 V, which is higher than those of commercially available Pt catalysts. The higher performance is also supported by a right-shifted onset potential. Our preparation is simple and could be applied to other metallic nanocrystals as a novel platform in catalysis, fuel cells and biosensors.     

Characterization by Stm and Electrical Conductivity of Single-Walled Carbon Nanotubes

Single-walled carbon nanotubes (SWCNT) prepared by a DC-Arc-Discharge and purified by a hydrothermal treatment followed by several steps of procedures including heating, burning, extracting and acid-washing are investigated by a conventional STM technique morphologically and spectroscopically. The electical resistivities of compacted pellets (mats) of SWCNT are measured as a function of temperature in the range from the room-temperature to 1.5K. The behaviors seems to be essentially originated in the metallic nature of individual SWCNT.     

Rodent Models of Nonalcoholic Fatty Liver Disease/Nonalcoholic Steatohepatitis

Research in nonalcoholic fatty liver disease (NAFLD), including nonalcoholic steatohepatitis (NASH), has been limited by the availability of suitable models for this disease. A number of rodent models have been described in which the relevant liver pathology develops in an appropriate metabolic context. These models are promising tools for researchers investigating one of the key issues of NASH: not so much why steatosis occurs, but what causes the transition from simple steatosis to the inflammatory, progressive fibrosing condition of steatohepatitis. The different rodent models can be classified into two large groups. The first includes models in which the disease is acquired after dietary or pharmacological manipulation, and the second, genetically modified models in which liver disease develops spontaneously. To date, no single rodent model has encompassed the full spectrum of human disease progression, but individual models can imitate particular characteristics of human disease. Therefore, it is important that researchers choose the appropriate rodent models. The purpose of the present review is to discuss the metabolic abnormalities present in the currently available rodent models of NAFLD, summarizing the strengths and weaknesses of the established models and the key findings that have furthered our understanding of the disease’s pathogenesis.     

Extremely Low Operating Voltage Green Phosphorescent Organic Light‐Emitting Devices

Organic light‐emitting devices (OLEDs) are expected to be adopted as the next generation of general lighting because they are more efficient than fluorescent tubes and are mercury‐free. The theoretical limit of operating voltage is generally believed to be equal to the energy gap, which corresponds to the energy difference between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) for the emitter molecule divided by the electron charge (e). Here, green OLEDs operating below a theoretical limit of the energy gap (E_g) voltage with high external quantum efficiency over 20% are demonstrated using fac‐tris(2‐phenylpyridine)iridium(III) with a peak emission wavelength of 523 nm, which is equivalent to a photon energy of 2.38 eV. An optimized OLED operates clearly below the theoretical limit of the E_g voltage at 2.38 V showing 100 cd m^?2 at 2.25 V and 5000 cd m^?2 at 2.95 V without any light outcoupling enhancement techniques.     

A Hydrogen Peroxide Activatable Gemcitabine Prodrug for the Selective Treatment of Pancreatic Ductal Adenocarcinoma

The main concern in the use of anticancer chemotherapeutic drugs is host toxicity. Patients need to interrupt or change chemotherapy due to adverse effects. In this study, we aimed to decrease adverse events with gemcitabine (GEM) in the treatment of pancreatic ductal adenocarcinoma and focused on the difference of hydrogen peroxide levels in normal versus cancer cells. We designed and synthesized a novel boronate-ester-caged prodrug that is activated by the high H₂O₂ concentrations found in cancer cells to release GEM. An H₂O₂-activatable GEM (A-GEM) has higher selectivity for H₂O₂ over other reactive oxygen species (ROS) and cytotoxic effects corresponding to the H₂O₂ concentration in vitro. A xenograft model of immunodeficient mice indicated that the effect of A-GEM was not inferior to that of GEM when administered in vivo. In particular, myelosuppression was significantly decreased following A-GEM treatment compared with that following GEM treatment.     

Control of Molecular Orientation in Organic Semiconductor Films using Weak Hydrogen Bonds

Use of the intrinsic optoelectronic functions of organic semiconductor films has not yet reached its full potential, mainly because of the primitive methodology used to control the molecular aggregation state in amorphous films during vapor deposition. Here, a universal molecular engineering methodology is presented to control molecular orientation; this methodology strategically uses noncovalent, intermolecular weak hydrogen bonds in a series of oligopyridine derivatives. A key is to use two bipyridin‐3‐ylphenyl moieties, which form self‐complementary intermolecular weak hydrogen bonds, and which do not induce unfavorable crystallization. Another key is to incorporate a planar anisotropic molecular shape by reducing the steric hindrance of the core structure for inducing π–π interactions. These synergetic effects enhance horizontal orientation in amorphous organic semiconductor films and significantly increasing electron mobility. Through this evaluation process, an oligopyridine derivative is selected as an electron‐transporter, and successfully develops highly efficient and stable deep‐red organic light‐emitting devices as a proof‐of‐concept.