Effect of [60] Fullerene on the Chondrogenesis in Mouse Embryonic Limb Bud Cell Culture System

Abstract

[60] Fullerene solubilized with polyvinylpyrrolidone (PVP) promoted the mouse embryonic limb bud cell differentiation specifically. The cell lysis caused by C60 was diminished by the addition of superoxide dismutase and catalase.     

Visible Light Irradiation of [60]Fullerene Causes Killing and Initiation of Transformation in Balb/3T3 Cells

Abstract

Cell transformation in vitro is a model of carcinogenesis in vivo. Two-stage transformation assay increases the sensitivity of cells to chemicals and permits detection of carcinogens acting as initiating agents. [60]Fullerene (C₆₀) was cytotoxic in BALB/3T3 cells when it was irradiated by visible light, but not without light irradiation. Under conditions when C₆₀ was cytotoxic, it acted as an initiating agent for cell transformation, but it did not act as a complete transforming agent. the initiating activity of visible-light-irradiated C₆₀ was statistically significant in a modified two-stage transformation assay including a procedure for replating cells treated by C₆₀ and light, but it was equivocal in the standard two-stage transformation assay.     

Out‐of‐Plane Strain Induced in a Moiré Superstructure of Monolayer MoS2 and MoSe2 on Au(111)

Making contact of transition metal dichalcogenides (TMDCs) with a metal surface is essential for fabricating and designing electronic devices and catalytic systems. It also generates strain in the TMDCs that plays significant role in both electronic and phonon structures. Therefore, detailed understanding of mechanism of the strain generation is important to fully comprehend the modulation effect for the electronic and phonon properties. Here, MoS₂ and MoSe₂ monolayers are grown on Au surface by chemical vapor deposition and it is demonstrated that the contact with a crystalline Au(111) surface gives rise to only out‐of‐plane strain in both MoS₂ and MoSe₂ layers, whereas no strain generation is observed on polycrystalline Au or SiO₂/Si surfaces. Scanning tunneling microscopy analysis provides information regarding consequent specific adsorption sites between lower S (Se) atoms in the S? Mo? S (Se? Mo? Se) structure and Au atoms via unique moiré superstructure formation for MoS₂ and MoSe₂ layers on Au(111). This observation indicates that the specific adsorption sites give rise to out‐of‐plane strain in the TMDC layers. Furthermore, it also leads to effective modulation of the electronic structure of the MoS₂ or MoSe₂ layer.     

Near-infrared imaging of water in a polymer electrolyte membrane during a fuel cell operation

A novel technique of spectroscopic imaging using a near-infrared (NIR) laser sheet beam was developed for visualization of liquid water in a proton-exchange membrane (PEM) sandwiched between two opaque electrodes set in a polymer electrolyte fuel cell (PEFC). In-plane two-dimensional distribution of water in the thin membrane was clearly visualized during the fuel cell operation. Under the condition of fuel feeding into the PEFC without humidification, water was generated by the fuel cell reaction in the whole electrode area. In contrast, under the condition of fuel feeding with humidification, the PEM got wet in the vicinity of a gas flow field locally.     

Crystal structure of poly[bis(3,4-dimethylphenoxy)phosphazene]

The crystal structure and chain conformation of poly[bis(3,4-dimethylphenoxy)phosphazene] — PB (dMe) PP — have been studied by X-ray diffraction techniques. The unit cell of this polymer shows an orthorhombic form with the crystallographic parameters a=2.05, b=1.49, c (chain axis)=0.998 nm. Its space group is determined as Pbcn-D _2h ¹⁴ where the molecular chains are located at the centre and each corner of the unit cell, which contains eight monomeric units; these molecular chains possibly have a — (trans ₃ cis)₂-conformation. The R factor calculated from the final crystal structure was estimated as 16.9%. As with other types of polyorganophosphazenes, the thermotropic transformation in PB (dMe) PP takes place from the three-dimensionally ordered state to its two-dimensional psuedohexagonal form (a _h = 1.49 nm), accompanied by a latent heat change at 96 °C.     

Chemically Tuned p‐ and n‐Type WSe2 Monolayers with High Carrier Mobility for Advanced Electronics

Monolayers of transition metal dichalcogenides (TMDCs) have attracted a great interest for post‐silicon electronics and photonics due to their high carrier mobility, tunable bandgap, and atom‐thick 2D structure. With the analogy to conventional silicon electronics, establishing a method to convert TMDC to p‐ and n‐type semiconductors is essential for various device applications, such as complementary metal‐oxide‐semiconductor (CMOS) circuits and photovoltaics. Here, a successful control of the electrical polarity of monolayer WSe₂ is demonstrated by chemical doping. Two different molecules, 4‐nitrobenzenediazonium tetrafluoroborate and diethylenetriamine, are utilized to convert ambipolar WSe₂ field‐effect transistors (FETs) to p‐ and n‐type, respectively. Moreover, the chemically doped WSe₂ show increased effective carrier mobilities of 82 and 25 cm² V^?1s^?1 for holes and electrons, respectively, which are much higher than those of the pristine WSe₂. The doping effects are studied by photoluminescence, Raman, X‐ray photoelectron spectroscopy, and density functional theory. Chemically tuned WSe₂ FETs are integrated into CMOS inverters, exhibiting extremely low power consumption ( ≈ 0.17 nW). Furthermore, a p‐n junction within single WSe₂ grain is realized via spatially controlled chemical doping. The chemical doping method for controlling the transport properties of WSe₂ will contribute to the development of TMDC‐based advanced electronics.     

Design for an aberration-corrected concave grating for a mid-infrared long-slit spectrometer

A new design for an aberration-corrected concave grating for the spectral region near 10 mum is presented. It was designed for use in the ground-based astronomical medium-resolution (lambda/Dlambda ~ 100) Mid-Infrared Camera and Spectrometer (MICS). It provides a flat focal plane for a wide spectral range (7.5-13.5 mum) with small aberrations, permitting efficient long-slit observations in the mid-infrared region. It permits a simple design of the spectrometer without collimator and camera mirrors, which is quite advantageous for cryogenic instruments. The grating has variable spacing grooves to reduce aberrations. In addition, the grating surface figure is designed to be toroidal and in the direction perpendicular to the grooves, aspherical, to suppress the aberrations further over a wide spectral range. The angle of the grooves is also varied to yield better efficiency near the blaze angle. The grating was fabricated by high-quality ultraprecision machining, which made these features possible. Test observations confirmed that the designed spectral resolution was achieved.