Bone Tissue Engineering in Rat Calvarial Defects Using Induced Bone-like Tissue by rhBMPs from Immature Muscular Tissues In Vitro

This study aimed to induce bone-like tissue from immature muscular tissue (IMT) in vitro using commercially available recombinant human bone morphogenetic protein (rhBMP)-2, rhBMP-4, and rhBMP-7, and then implanting this tissue into a calvarial defect in rats to assess healing. IMTs were extracted from 20-day-old Sprague-Dawley (SD) fetal rats, placed on expanded polytetrafluoroethylene (ePTFE) with 10 ng/μL each of rhBMP-2, BMP-4, and BMP-7, and cultured for two weeks. The specimens were implanted into calvarial defects in 3-week-old SD rats for up to three weeks. Relatively strong radiopacity was observed on micro-CT two weeks after culture, and bone-like tissue, comprising osteoblastic cells and osteoids, was partially observed by H&E staining. Calcium, phosphorus, and oxygen were detected in the extracellular matrix using an electron probe micro analyzer, and X-ray diffraction patterns and Fourier transform infrared spectroscopy spectra of the specimen were found to have typical apatite crystal peaks and spectra, respectively. Furthermore, partial strong radiopacity and ossification were confirmed one week after implantation, and a dominant novel bone was observed after two weeks in the defect site. Thus, rhBMP-2, BMP-4, and BMP-7 differentiated IMT into bone-like tissue in vitro, and this induced bone-like tissue has ossification potential and promotes the healing of calvarial defects. Our results suggest that IMT is an effective tissue source for bone tissue engineering.     

Bile Acid–Drug Interaction via Organic Anion-Transporting Polypeptide 4C1 Is a Potential Mechanism of Altered Pharmacokinetics of Renally Excreted Drugs

Patients with liver diseases not only experience the adverse effects of liver-metabolized drugs, but also the unexpected adverse effects of renally excreted drugs. Bile acids alter the expression of renal drug transporters, however, the direct effects of bile acids on drug transport remain unknown. Renal drug transporter organic anion-transporting polypeptide 4C1 (OATP4C1) was reported to be inhibited by chenodeoxycholic acid. Therefore, we predicted that the inhibition of OATP4C1-mediated transport by bile acids might be a potential mechanism for the altered pharmacokinetics of renally excreted drugs. We screened 45 types of bile acids and calculated the IC₅₀, K_i values, and bile acid–drug interaction (BDI) indices of bile acids whose inhibitory effect on OATP4C1 was >50%. From the screening results, lithocholic acid (LCA), glycine-conjugated lithocholic acid (GLCA), and taurine-conjugated lithocholic acid (TLCA) were newly identified as inhibitors of OATP4C1. Since the BDI index of LCA was 0.278, LCA is likely to inhibit OATP4C1-mediated transport in clinical settings. Our findings suggest that dose adjustment of renally excreted drugs may be required in patients with renal failure as well as in patients with hepatic failure. We believe that our findings provide essential information for drug development and safe drug treatment in clinics.     

Effect of annealing conditions on the uniformity of undoped Semi-Insulating InP

Recently, it was found that undoped semi-insulating InP can be obtained by highpressure annealing of high purity materials. The reproducibility and the uniformity was, however, not satisfactory. In the present work, we found that not only Fe concentrations but also Cr and Ni concentrations in annealed wafers were slightly increased during annealing. Since it seems that the origin of the contamination was due to the vapor source of red phosphorus, conductive InP with a trace amount of Fe was annealed under low phosphorus vapor pressure in order to reduce the contamination. By preventing the contamination of Cr and Ni, preparation of semi-insulating InP became highly reproducible. The minimum Fe concentration for realizing semi-insulating InP was found to be 1 x 10¹⁵cm⁻³. It was also found that the better resistivity uniformity can be obtained at higher annealing temperatures.     

Experimental examination of the characteristics of bright-field scanning confocal electron microscopy images

We experimentally examined the characteristics of bright-field (BF) scanning confocal electron microscopy (SCEM) images by changing the observation conditions and comparing the images with those obtained by BF transmission electron microscopy (TEM) and BF scanning TEM (STEM) modes. The observation of 5-nm-diameter Au nanoparticles demonstrated that BF-SCEM produces object elongation of more than 2000?nm along the optical axis, as do BF-TEM and BF-STEM. We demonstrated the relationship between elongation length and geometric effects such as convergence and collection angles of a probe and the lateral size of an object; the relationship is consistent with previous theoretical prediction. Further, we observed interesting features that are seen only in the BF-SCEM images; the film contrast was strongly enhanced, compared with that of BF-STEM. In addition, a bright contrast appeared around the object position in the elongated images. Using this characteristic, we could determine the object position and structure.     

High-mobility ultrathin strained Ge MOSFETs on bulk and SOI with low band-to-band tunneling leakage: experiments

For the first time, the tradeoffs between higher mobility (smaller bandgap) channel and lower band-to-band tunneling (BTBT) leakage have been investigated. In particular, through detailed experiments and simulations, the transport and leakage in ultrathin (UT) strained germanium (Ge) MOSFETs on bulk and silicon-on-insulator (SOI) have been examined. In the case of strained Ge MOSFETs on bulk Si, the resulting optimal structure obtained was a UT low-defect 2-nm fully strained Ge epi channel on relaxed Si, with a 4-nm Si cap layer. The fabricated device shows very high mobility enhancements >3.5/spl times/ over bulk Si devices, 2/spl times/ mobility enhancement and >10/spl times/ BTBT reduction over 4-nm strained Ge, and surface channel 50% strained SiGe devices. Strained SiGe MOSFETs having UT (T/sub Ge/<3 nm) very high Ge fraction (/spl sim/ 80%) channel and Si cap (T/sub Si cap/<3 nm) have also been successfully fabricated on thin relaxed SOI substrates (T/sub SOI/=9 nm). The tradeoffs in obtaining a high-mobility (smaller bandgap) channel with low tunneling leakage on UT-SOI have been investigated in detail. The fabricated device shows very high mobility enhancements of >4/spl times/ over bulk Si devices, >2.5/spl times/ over strained silicon directly on insulator (SSDOI; strained to 20% relaxed SiGe) devices, and >1.5/spl times/ over 60% strained SiGe (on relaxed bulk Si) devices.     

New conceptual three-phase current-fed soft switching pulse width modulation converter with switched capacitor type resonant dc link

This paper presents a novel prototype of three-phase current-fed PWM converter with a switched capacitor type resonant dc link snubber circuit, which can basically operate under a principle of zero current soft switching commutation. The optimum PWM pattern-based control scheme proposed by the authors is effectively applied for this active converter. In this paper, the steady-state operating principle of a new converter circuit treated here is described. The practical design procedure of this converter is discussed from a theoretical point of view. The feasible experiment to confirm zero current soft switching commutation of this converter is concretely implemented and evaluated herein.     

A 500-MHz 4-Mb CMOS pipeline-burst cache SRAM with point-to-pointnoise reduction coding I/O

A 32-b 500-MHz 4-1-1-1 operation 4-Mb pipeline burst cache SRAM has been developed. In order to achieve both high bandwidth operation and short latency operation, we developed the following technologies: 1) a prefetched pipeline-burst scheme with double late-write buffers, 2) gate size reduction and a bit-line equalization by source resetting, 3) point-to-point bidirectional coding I/O's to reduce bus noise and power consumption, and 4) a three-level metal 0.25-μm CMOS process technology with six transistor memory cells     

Development of 170 GHz/500 kW gyrotron

A development of 170GHz/500kW level gyrotron was carried out as R&D work of ITER. The oscillation mode is TE_31,8. In a short pulse experiment, the maximum power of 750kW was achieved at 85kV/40A. The efficiency was 22%. In the depressed collector operation, 500kW/36%/50ms was obtained. The maximum efficiency of 40% was obtained at P_RF=470kW whereas the power decrease by the electron trapping was observed. Pulse extension was done up to 10s at P_RF=170kW with the depressed collector operation. The power was limited by the temperature increase of the output window.     

A 0.1-μm delta-doped MOSFET fabricated with post-low-energyimplanting selective epitaxy

A simple fabrication technology for delta-doped MOSFETs, named post-low-energy implanting selective epitaxy (PLISE) is presented. The PLISE technology needs no additional photo-lithography mask, deposition step or etching step even for CMOS devices. The only additional step is growing undoped epitaxial channel layers by UHV-CVD after the channel implantation. With this technology, delta-doped NMOSFETs with 0.1-μm gate length were successfully fabricated. By optimizing the epi-layer thickness and the channel doping level, short-channel effects are suppressed enough to achieve 0.1-μm gate length. Moreover, the junction capacitance at zero bias is reduced by 50%     

Uniformity of deep levels in semi-insulating InP obtained by multiple-step wafer annealing

The uniformity of deep levels in semi-insulating InP wafers, which have been obtained by multiple-step wafer annealing under phosphorus vapor pressure, was studied using the thermally stimulated current (TSC) and photoluminescence (PL) methods. Only three traps related to Fe, T₀ (ionization energy E_i=0.19 eV), T₁ (0.25 eV), and T₂ (0.33 eV), probably forming complex defects, were observed in the wafer and they exhibited a relatively uniform distribution. PL spectra relating to phosphorus vacancies observed in some regions of the wafer are correlated with a small TSC signal having an ionization energy of 0.43 eV.