High-performance Ge/Si electro-absorption optical modulator up to 85°C and its highly efficient photodetector operation

We studied a high-speed Ge/Si electro-absorption optical modulator (EAM) evanescently coupled with a Si waveguide of a lateral p–n junction for a high-bandwidth optical interconnect over a wide range of temperatures from 25 °C to 85 °C. We demonstrated 56 Gbps high-speed operation at temperatures up to 85 °C. From the photoluminescence spectra, we confirmed that the bandgap energy dependence on temperature is relatively small, which is consistent with the shift in the operation wavelengths with increasing temperature for a Ge/Si EAM. We also demonstrated that the same device operates as a high-speed and high-efficiency Ge photodetector with the Franz-Keldysh (F-K) and avalanche-multiplication effects. These results demonstrate that the Ge/Si stacked structure is promising for both high-performance optical modulators and photodetectors integrated on Si platforms

The Fungal Metabolite (+)-Terrein Abrogates Ovariectomy-Induced Bone Loss and Receptor Activator of Nuclear Factor-kappa B Ligand-Induced Osteoclastogenesis by Suppressing Protein Kinase-C alpha/beta II Phosphorylation

Osteoporosis is a common disease characterized by a systemic impairment of bone mass and microarchitecture that results in fragility fractures. Severe bone loss due to osteoporosis triggers pathological fractures and consequently decreases the daily life activity and quality of life. Therefore, prevention of osteoporosis has become an important issue to be addressed. We have reported that the fungal secondary metabolite (+)-terrein (TER), a natural compound derived from Aspergillus terreus, has shown receptor activator of nuclear factor-kappa B ligand (RANKL)-induced osteoclast differentiation by suppressing nuclear factor of activated T-cell 1 (NFATc1) expression, a master regulator of osteoclastogenesis. TER has been shown to possess extensive biological and pharmacological benefits; however, its effects on bone metabolism remain unclear. In this study, we investigated the effects of TER on the femoral bone metabolism using a mouse-ovariectomized osteoporosis model (OVX mice) and then on RANKL signal transduction using mouse bone marrow macrophages (mBMMs). In vivo administration of TER significantly improved bone density, bone mass, and trabecular number in OVX mice (p < 0.01). In addition, TER suppressed TRAP and cathepsin-K expression in the tissue sections of OVX mice (p < 0.01). In an in vitro study, TER suppressed RANKL-induced phosphorylation of PKC alpha/beta II, which is involved in the expression of NFATc1 (p < 0.05). The PKC inhibitor, GF109203X, also inhibited RANKL-induced osteoclastogenesis in mBMMs as well as TER. In addition, TER suppressed the expression of osteoclastogenesis-related genes, such as Ocstamp, Dcstamp, Calcr, Atp6v0d2, Oscar, and Itgb3 (p < 0.01). These results provide promising evidence for the potential therapeutic application of TER as a novel treatment compound against osteoporosis

Three-dimensional visualization of intrauterine conceptus through the uterine wall by tissue clearing method

金沢大学医薬保健研究域医学系Visualization of specific cells in the three-dimensional organ architecture is one of the key steps to develop our knowledge about pathophysiological mechanisms in various organs. In this study, we successfully obtained stereoscopic whole images of the intrauterine murine embryo and placenta through the uterus using a modified tissue clearing CUBIC method. By this procedure, we can recognize the three-dimensional relationships among various tissues within the pregnant uterus and analyze free-angle images of cross-sections with single-cell resolution using a computer system. Based on these data, we can select optimal cross-section angles and then produce the corresponding tissue slices that are adequate for further immunohistochemical examination. Furthermore, using transgenic mice, distinct images of an EGFP-positive embryo and the placenta can be obtained, confirming the precise three-dimensional location of invading trophoblasts in the feto-maternal interface in the uterus. These results indicate that this procedure will significantly contribute to analyzing pathophysiological mechanisms in reproductive organs. © 2017 The Author(s)

IJTC2007-44012 DYNAMIC INDENTAION CHARACTERISTICS OF SPHERICAL SLIDERS COLLIDING WITH STATIONARY MAGNETIC DISKS WITH A THIN LUBRICANT LAYER

ABSTRACT We measured the dynamic adhesion force when spherical sliders with a radius of 1 and 2 mm collided with smooth magnetic disks with lubricant layers of zero, 1, 2, and 3 nm thickness to clarify the dynamic interfacial force between a slider and disk in the nanometer region of flying height. From the measured slider velocity, we calculated the relationship between acceleration (acting force) and displacement. We found that a strong adhesion force observed at zero lubricant vanishes when 1-nm thick lubricant with UV is applied. As the mobile lubricant thickness was increased, we observed a clear dynamic adhesion force at the instant of separation. These results indicate that adhesion force is most likely to result from meniscus formation. INTRODUCTION Since a flying head slider tends to exhibit bouncing vibration in sub-10 nanometer flying height, finding the origin of attraction and friction forces in slider/disk nanometer spacing is important. Although some researchers Since many researchers still believe that meniscus cannot form during a short duration of contact when the slider exhibit

Disjoining Pressure Derived from the Lennard–Jones Potential, Diffusion Equation, and Diffusion Coefficient for Submonolayer Liquid Film

In magnetic hard disk drives, it is important to evaluate the replenishment effect of a submonolayer lubricant film under a more severe condition that the head&ndash;disk spacing has to be reduced from the current 0.7 nm to ~0.5 nm. In contrast to the prevailing conventional diffusion equation validated for multilayer liquid film, the author has already proposed a new diffusion equation more suitable for submonolayer film by intuitively incorporating the density reduction effect in the submonolayer liquid film. This paper presents a rigorous derivation of the disjoining pressure (DP) from Lennard&ndash;Jones potential (LJP) and formulated the diffusion equation incorporating the DP. The difference in the rigorous DP and diffusion equation from the previous versions is negligibly small except in a small film thickness less than the van der Waals (vdW) distance. The theoretical relationship between the vdW distance in the DP and the molecular force equilibrium distance in the LJP is elucidated. Rigorous derivations of the DP and diffusion equation for multilayer liquid film from the LJP are also presented. The superiority of the submonolayer diffusion equation over the conventional equation in the submonolayer film regime is demonstrated by comparing their theoretical diffusion coefficients with Waltman&rsquo;s experimental data