Cryogenic STM/STS observation on oxide superconductors

The topographic and electronic properties of the surfaces of (001) and (110) oriented YBa₂Cu₃O_y, epitaxial films have been probed by atomic resolution STM/STS at 4.2 K. The STM image on the (001) surface clearly revealed the atomic corrugation of the tetragonal lattice with an average spacing of 0.4 nm. while on the (110) surface the orthorhombic atomic lattice, corresponding to the Cu atoms of both CuO₂ and CuO chain planes, was observed. The STS result on the (001) surface indicated the semiconducting nature of the terminating layer. As the tunneling tip came closer to the surface, however, the shape of the tunneling spectrum became more metallic and showed a superconducting energy gap, which seems to arise from the underlying superconducting layer. On the other hand, the tunneling spectra on the (110) surface indicated superconducting gap structures, independent of the tip-sample distance.     

Thickness Change in Molecularly Thin Lubricant Under Flying Head in Hard Disk Drives

In hard disk drives (HDDs), lubricants on disks are very important material to reduce head and disk wear. Thus, it is necessary to know changes in lubricant thickness to keep lubricant thickness constant on rotating disks. For this purpose, we have to know changes in lubricant thickness during HDD operations. We developed a simulation program to simulate changes in lubricant thickness during HDD operations numerically. First, we had simulated the changes in lubricant thickness of 10-nm-thick non-polar lubricant film under a flying head. The result corresponded to a reported experimental result. In recent HDDs, a lubricant thickness has become molecularly thin and lubricants with polar end groups have been used. In molecularly thin polar lubricants, diffusion depends on their thickness and their viscosity becomes very high. Next, we simulated the change in the lubricant thickness of 2-nm-thick polar lubricant film considering the effects of lubricant initial thickness. The simulated results showed that the changes were very small in 2-nm-thick lubricant film, but they were not confirmed with the experiment. In this paper, experimental results of the change in the thickness of molecularly thin non-polar and polar lubricants under a flying head were first measured. The simulations that took account of thickness-dependent diffusion and thin-film viscosity were then performed with the simulation parameters based on the experiments. The simulated results of lubricant distribution were in good agreement with the experimental results.     

Moisture buffering and effect of ventilation rate and volume rate of hygrothermal materials in a single room under steady state exterior conditions

In this paper, experiments and simulations investigating the moisture buffering of the gypsum boards are described. A test chamber was used for the experiments. The gypsum board was installed on the interior surface in the test chamber. This chamber was located in a climate chamber. The ambient condition of the chamber was controlled at constant temperature and humidity. In the experiment three cases of ventilation rate, no ventilation, 1.0 air change per hour and 5.0 air changes per hour, were investigated. In the experiment the relationship between moisture buffering and volume rate of the materials, various area and locations of the gypsum boards on the surrounding walls were investigated.     

Possibility of Thermal Protection in Earth Re-entry Flight by MHD Flow Control with Air-Core Circular Magnet

The possibility of thermal protection in an earth re-entry flight by the magnetohydrodynamic (MHD) flow control with an air-core circular magnet producing about 1 T or less on the wall surface of a space vehicle is examined by r-z two-dimensional numerical simulations. The present study adopts a hemisphere with a radius of 1.0 m as the nose shape of a space vehicle. The numerical results show that aerodynamic heating can be reduced by the MHD flow control with an air-core circular magnet, and also that the maximum wall heat flux and the effect of the MHD flow control become prominent with the magnitude of coil current and the flight altitude. Furthermore, it is found that there is an optimum magnet size to maximize the effect of MHD flow control under constant exciting magnetic energy, and also the optimum size gets reduced with the decrease in the flight altitude. © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

A New Lead Identification Strategy: Screening an sp3-rich and Lead-like Compound Library Composed of 7-Azanorbornane Derivatives

Although the advantages of sp³-rich, sterically complicated molecules in drug development have been pointed out, modern screening libraries are filled with planar, sp²-rich components. Compounds that are sp³-rich are difficult to synthesize, and thus we aimed to invent an efficient method to construct sp³-rich libraries. By modifying sp³-rich 7-azanorbornane scaffolds through click chemistry, we efficiently prepared a small set of compounds. These compounds were not only sp³-rich, but also had sufficient “lead-like” properties in view of molecular weights and hydrophobicity. Screening assays of this library provided weak κ opioid receptor agonists and growth hormone secretagogue receptor agonists with high hit rates. These results indicate that the 7-azanorbornane scaffold may be a “privileged structure” for lead identification in drug discovery.     

Upregulated Expression of Activation-Induced Cytidine Deaminase in Ocular Adnexal Marginal Zone Lymphoma with IgG4-Positive Cells

Immunoglobulin G4-related disease (IgG4-RD) is a systemic disorder characterized by tissue fibrosis and intense lymphoplasmacytic infiltration, causing progressive organ dysfunction. Activation-induced cytidine deaminase (AID), a deaminase normally expressed in activated B-cells in germinal centers, edits ribonucleotides to induce somatic hypermutation and class switching of immunoglobulin. While AID expression is strictly controlled under physiological conditions, chronic inflammation has been noted to induce its upregulation to propel oncogenesis. We examined AID expression in IgG4-related ophthalmic disease (IgG4-ROD; n = 16), marginal zone lymphoma with IgG4-positive cells (IgG4+ MZL; n = 11), and marginal zone lymphoma without IgG4-positive cells (IgG4- MZL; n = 12) of ocular adnexa using immunohistochemical staining. Immunohistochemistry revealed significantly higher AID-intensity index in IgG4-ROD and IgG4+ MZL than IgG4- MZL (p < 0.001 and = 0.001, respectively). The present results suggest that IgG4-RD has several specific causes of AID up-regulation in addition to inflammation, and AID may be a driver of oncogenesis in IgG4-ROD to IgG4+ MZL.     

广州市老年人使用空气调节设备状况及对健康影响调查

老人的健康与建筑室内环境存在重要联系，为了给适老建筑的暖通系统优化设计提供理论依据，有必要探究室内空气调节设备与老人健康的关系。对广州市104位本地老年人进行了问卷调查，收集了老年人的基本健康信息和家庭使用空气调节设备的情况，包括制冷、除湿、采暖和空气净化4种设备及其使用时长，使用习惯。收集到的信息用SPSS20.0进行了统计分析。结果包括广州市老年人家中四种设备拥有率、设备平均使用龄、设备使用时间以及常见日均使用时长；所调查的老年人健康比例达到55.8%。患病老人中心血管疾病的比例最高，其余为风湿性疾病和关节炎等疾病。相关性分析表明，广州地区夏天家庭采取制冷措施的老人患病可能性更小；制冷设备常见日均使用时长与身处空调区域时长的比值越大，老人患病的可能性越小。     

Engineering surface and development of a new DNA micro array chip

This paper proposes a new concept of the ‘engineering surface’, which extends the conventional idea of a functional surface by combining it with micro/nano manufacturing technology. Characteristic features and possibilities of the engineering surface are discussed in detail. This paper reviews studies on micro/nano fabrication technologies for advanced materials and evaluation technology for surface function. New fabrication technologies, micro machining and nano forming, are introduced, which will be basic manufacturing processes of the engineering surface. Also, a new surface evaluation technique is introduced for the surface energy of the nano fabricated surface. Design of a new DNA micro array chip is introduced as an example of applications of the engineering surface. Controllability of surface property by nano fabrication is studied.     

Temperature‐Dependent Tip‐Induced Motion of Ga Adatom on GaAs (110) Surface

The temperature‐dependent tip‐induced‐motion of a Ga adatom on a GaAs (110) surface is experimentally demonstrated using scanning tunneling microscopy (STM). The surface adsorption energy profile obtained by first‐principle electronic structure calculations reveals that the origin of the Ga motion observed at 78 K is attributable to the tip‐induced Ga adatom hopping between the most stable potential minima among the three local minima, whereas that observed at 4.2 K is attributable to the tip‐induced hopping and sliding motions through the next stable minima as well as the most stable minima. Furthermore, it is shown that a slight progressive modification of the adatom motion observed only at 4.2 K resulting from repeated STM line scans is consistent with the overall picture taking account of the heating of the adatom owing to the tip current.     

Photosensitizing Metasurface Empowered by Enhanced Magnetic Field of Toroidal Dipole Resonance

Photochemical reaction exploiting an excited triplet state (T₁) of a molecule requires two steps for the excitation, i.e., electronic transition from the ground (S₀) to singlet excited (S₁) states and intersystem crossing to the T₁ state. A dielectric metasurface coupled with photosensitizer that enables energy efficient photochemical reaction via the enhanced S₀→T₁ magnetic dipole transition is developed. In the direct S₀→T₁ transition, the photon energy of several hundreds of meV is saved compared to the conventional S₀→ S₁→T₁ transition. To maximize the magnetic field intensity on the surface, a silicon (Si) nanodisk array metasurface with toroidal dipole resonances is designed. The surface of the metasurface is functionalized with ruthenium (Ru(II)) complexes that work as a photosensitizer for singlet oxygen generation. In the coupled system, the rate of the direct S₀→T₁ transition of Ru(II) complexes is 41-fold enhanced at the toroidal dipole resonance of a Si nanodisk array. The enhancement of a singlet oxygen generation rate is observed when the toroidal dipole resonance of a Si nanodisk array is matched with the direct S₀→T₁ transition wavelength of Ru(II) complexes.