Generation of human induced pluripotent stem cells from oral mucosa

Induced pluripotent stem (iPS) cells are one of the most promising sources for cell therapy in regenerative medicine. Using a patient's own genetically identical and histocompatible cells is the ideal way to practice personalized regenerative medicine. For personalized iPS cell therapy, the prerequisites for cell source preparation are a simple and safe procedure, no aesthetic or functional damage, and quick wound healing. Oral mucosa fibroblasts (OFs) may have high potential to fulfill these requirements. In this study, biopsy was performed in a dental chair; no significant incisional damage was recognized and rapid wound healing (within a week) was observed. We generated human iPS cells from the isolated OFs via the retroviral gene transfer of OCT4, SOX2, c-MYC, and KLF4. Reprogrammed cells showed ES-like morphology and expressed undifferentiated markers such as OCT4, NANOG, SSEA4, TRA-1-60, and TRA-1-81. Subsequent in vitro and in vivo analyses confirmed the pluripotency of resultant iPS cells, which matched the criteria for iPS cells. In addition, we found that the endogenous expression levels of c-MYC and KLF4 in OFs were similar to those in dermal fibroblasts. Taken together, we propose that OFs could be a practical source for preparing iPS cells to achieve personalized regenerative medicine in the near future.     

Effect of G-jitter on the thermocapillary convection experiment in ISS

Effects of g-jitter on the measurement of dynamic surface deformations (DSD) caused by the oscillatory thermocapillary convection in a liquid bridge have been studied experimentally. A vibration table driven by a piezoelectric actuator is constructed to generate g-jitters of realistic amplitude and frequency spectra. A microimaging displacement meter is used to measure DSD in the presence of g-jitter. It is shown that the natural DSD in the oscillatory state of thermocapillary convection is well separated in the frequency domain from that caused by harmonic and non-harmonic g-jitters. It is concluded that the DSD measurement in the future ISS experiment is feasible even in the presence of g-jitter there.     

Dynamic deformation behavior of ultrafine grained aluminum produced by ARB and subsequent annealing

Commercial purity aluminum (1100-Al) sheets with various grain sizes, ranging from 0.2 to 10 μm, were fabricated through accumulative roll bonding (ARB) and subsequent annealing at various temperatures. Mechanical properties of these materials were examined at various strain rates ranging from 10^?2 to 10³ s^?1 (from quasi-static deformation to dynamic deformation). Yield strength of the UFG specimens did not change so much when the strain rate changed. Yielding behavior of the UFG Al with grain size of 1.4 µm was characterized by yield-drop phenomenon, which appeared at higher strain rate. It was found that strain-hardening of the Al matrix was significantly enhanced at high strain rates, which was independent of the grain size. Uniform elongation increased with increasing strain rate in the specimens with the grain size larger than 1 µm, while post-uniform elongation increased with increasing strain rate in the submicrometer grain-sized specimens. Consequently, total elongation of all specimens was improved as the strain rate increased.     

Chemical reaction of hydrogenated diamond surface with amino acids by using N-chlorosuccinimide

Various organic compounds can be immobilized on a diamond surface if a chemically active organic functional group, such as an NH₂ group, is introduced on the diamond surface. We therefore attempted to introduce an NH₂ group on a diamond surface by using chemical reaction of a hydrogenated diamond surface with an amino acid and NCS (N-chlorosuccinimide). From our previous experimental results (Diamond Relat. Mater., 15, 668 (2006)), we expected that a functional group could be introduced on the diamond surface. However, there was no peak assigned to the NH₂ group in the IR spectra for diamond powder treated with amino acids. The diamond powder treated with L-serine, L(?)-threonine, L(?)-phenylalanine, L(+)-arginine, L-histidine, or L-asparagine monohydrate had a specific peak at 2275 cm^? 1 in the IR spectra. Moreover, the diamond powder treated with L(?)-threonine had the highest intensity of the peak at 2275 cm^? 1. Therefore, the chemical reaction of a hydrogenated diamond surface with L(?)-threonine was further examined in detail. Unfortunately, the assignment of the peak at 2275 cm^? 1 was unclear. However, we speculate from the compounds in the chemical reaction process that the peak is assigned to the CN group, although the peak position is slightly different from that of the normal CN group.     

Analysis and modeling of ants’ behavior from single to multi-body

In order to shed light on the collective behavior of social insects, we analyzed the behavior of ants from single to multi-body. In an experimental set-up, ants are placed in hemisphere without a nest and food. Trajectory of ants is recorded. From this bottom-up approach, we found that collective behavior of ants as follows: 1. Activity of single ant increases and decreases periodically. 2. Spontaneous meeting process is observed between two ants and meeting spot of two ants is localized in hemisphere. 3. Result on division of labor is obtained between two ants. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

30 Gb/s Over 100-m MMFs Using 1.1-$mu$ m Range VCSELs and Photodiodes

We developed 1.1-mum-range vertical-cavity surface-emitting lasers based on InGaAs-GaAs quantum wells, back-illuminated InGaAs photodiodes, and transimpedance amplifiers (InP heterojunction bipolar transistor) for high-speed optical interconnection. Clear eye opening operation and error-free transmission at 30 Gb/s over 100-m multimode fibers (GI32) were successfully achieved for the first time.     

Application of muscle microdialysis to evaluate the concentrations of the fluoroquinolones pazufloxacin and ofloxacin in the tissue interstitial fluids of rats

Muscle microdialysis has been used to determine the unbound concentrations of the fluoroquinolones, pazufloxacin and ofloxacin, in tissue interstitial fluids (Cisf,u) of rats under steady state conditions. Cisf,u was estimated from the concentration in dialysate and the in-vitro permeability rate constant by the extrapolation method based on the clearance concept. Paper-disks were inserted under the abdominal skin of rats, and the drug concentrations in the fluids penetrating into the disks (Cdisk) were measured and compared with Cisf,u. The Cisf,u of pazufloxacin and ofloxacin in muscle were close to their unbound concentrations in the venous plasma; these were 75.3% and 77.1%, respectively, of the total concentrations in plasma at the steady state. The Cdisk of pazufloxacin and ofloxacin were also close to their Cisf,u. These results indicate that the unbound concentrations of the fluoroquinolones in the tissue interstitial fluids were the same as those in the venous plasma. The disk insertion technique seems to be useful for evaluating drug concentrations in tissue interstitial fluid.     

Evaluation of the optical-coupling efficiency of InGaAlAs-InGaAsP butt joint using a novel multiple butt-jointed laser

We quantitatively estimated the optical-coupling efficiency at the InGaAlAs-InGaAsP butt-joint (BJ) part by fabricating a novel multiple-butt-jointed (MBJ) laser. The lasing characteristics of InGaAlAs-InGaAsP MBJ lasers formed by in situ cleaning process showed a high optical-coupling efficiency of approximately 98%, which is comparable to that of a conventional InGaAsP-InGaAsP MBJ lasers. Thus, high-quality BJ-based heterointegration of InGaAlAs and InGaAsP was successfully demonstrated.     

Isolation and characterization of a novel hydrogen-producing strain Clostridium sp. suitable for immobilization

A hydrogen-producing strain of bacteria suitable for immobilization was isolated from anaerobic sludge obtained from a methane fermentation plant. The isolated strain, CFPA-20 was identified as a novel species of the genus Clostridium by phylogenetic analysis of the 16S rRNA sequence. The changes in free energy of interaction of adhesion to polymer resin and self-aggregation were both negative. This indicated that CFPA-20 was thermodynamically favored for immobilization. CFPA-20 grew at a temperature range of 25–37 °C and at a pH range of 4.5–9.0. Immobilization of CFPA-20 on block copolymer polyethylene glycol-b-polypropylene glycol gave a radically improved hydrogen production yield (2.91 mol/mol-glucose) and a maximum hydrogen production rate (568 mL/L-culture/h) compared to the non-immobilized isolate. In addition, the biofilm of CFPA-20 acquired tolerance for volatile fatty acids. Further investigation into this mechanism may ultimately improve the hydrogen production capacity of CFPA-20.