10 GHz-spaced arrayed-waveguide grating multiplexer withphase-error-compensating thin-film heaters

An arrayed-waveguide grating multiplexer with thin-film heaters is fabricated to compensate for phase errors in arrayed waveguides. The phase errors are measured by Fourier transform spectroscopy with a low-coherence interferometer and are used as a monitor when we adjust the phases by controlling thin-film heaters. A channel crosstalk of -25 dB and a loss of 4.2 dB are achieved in a 5×5 10 GHz-spaced multiplexer     

Expression and function of murine receptor tyrosine kinases, TIE and TEK, in hematopoietic stem cells

Two highly related receptor tyrosine kinases, TIE and TEK, comprise a family of endothelial cell-specific kinase. We established monoclonal antibodies against them and performed detailed analyses on their expression and function in murine hematopoietic stem cells (HSCs). TIE and TEK were expressed on 23.7% and 33.3% of lineage marker-negative, c-Kit+ and Sca-1+ (Lin- c-Kit+ Sca-1+) HSCs that contain the majority of day-12 colony-forming units-spleen (CFU-S) and long-term reconstituting cells, but not committed progenitor cells. Lin- c-Kit+ Sca-1+ cells were further divided by the expression of TIE and TEK. TIE+ and TEK+ HSCs as well as each negative counterpart contained high proliferative potential colony-forming cells and differentiated into lymphoid and myeloid progenies both in vitro and in vivo. However, day-12 CFU-S were enriched in TIE+ and TEK+ HSCs. Our findings define TIE and TEK as novel stem cell marker antigens that segregate day-12 CFU-S, and provide evidence of novel signaling pathways that are involved in the functional regulation of HSCs at a specific stage of differentiation, particularly of day-12 CFU-S.     

PPO-ethanol system as wavelength shifter for the Cherenkov counting technique using a liquid scintillation counter

2, 5-diphenyloxazole (PPO) has been proposed as a wavelength shifter for Cherenkov counting. Since PPO is not incorporated with water, we have introduced the fluor into water in the form of micelle using a PPO-ethanol system. This technique makes it possible to obtain a high Cherenkov counting efficiency under stable sample conditions, attributed to the proper spectrometric features of the PPO. The ³²P Cherenkov counting efficiency (68.4%) obtained from this technique is large as that measured with a conventional Cherenkov technique.     

New model and scheme for compressible fluids of the finite difference lattice Boltzmann method and direct simulations of aerodynamic sound

A new scheme for the finite difference lattice Boltzmann method is proposed, in which negative viscosity term is introduced to reduce the viscosity and the calculation time can be remarkably reduced for high Reynolds number flows. A model with additional internal degree of freedom is also presented for diatomic gases such as air, in which an additional distribution function is introduced. Direct simulations of aero-acoustics by using the proposed model and scheme are presented. Speed of sound is correctly recovered. As typical examples, the Aeolian tone emitted by a circular cylinder is successfully simulated even very low Mach number flow. Full three-dimensional sound emission is also given.     

Development of microconnector with an automatic connecting/disconnecting mechanism

We developed microconnectors with an automatic connecting/disconnecting mechanism using magnetic force. The electrical terminals were designed to minimize the friction force during connection/disconnection and were fabricated using a deep X-ray lithography technique. The diameter and thickness of the microconnector are 2.5 mm and 2 mm, respectively. We confirmed the electrical connection at 160 mA/line and the automatic connection/disconnection at a distance of 600 μm between opposing microconnectors.     

Defect-Tolerance in Cellular Nanocomputers

For the manufacturing of computers built by nanotechnology, defects are expected to be a major problem. This paper explores this issue for nanocomputers based on cellular automata. Known for their regular structure, such architectures promise cost-effective manufacturing based on molecular self-organization. We show how a cellular automaton can detect defects in a self-contained way, and how it configures circuits on its cells while avoiding the defects. The employed cellular automaton is asynchronous, i.e., it does not require a central clock to synchronize the updates of its cells. This mode of timing is especially suitable for the high integration densities of nanotechnology implementations, since it potentially causes less heat dissipation.