Reaction-Formed Porous Yb4Si2N2O7 Materials with Uniform Open-Cell Network Structure

A novel porous Yb₄Si₂O₇N₂ material with uniform open-cell network structure was fabricated from the reaction between Si₃N₄, Yb₂O₃, and SiO₂. The formation of Yb₄Si₂O₇N₂ during heating was studied using X-ray diffractometry. The porous structure was characterized using scanning electron microscopy and mercury porosimeter. It is shown that the formation of Yb₄Si₂O₇N₂ phase starts at ∼1150°C and completes at 1350°C for 4 h, accompanied by the development of open-cell network structure. The necks between Yb₄Si₂O₇N₂ particles become much thicker with increasing temperature because of the coarsening of Yb₄Si₂O₇N₂ particles, thus leading to a uniform three-dimensional network structure. Furthermore, the pore size can be well controlled by adjusting reacting temperature and altering atmosphere.     

Time Resolved Ion Beam Induced Current measurements on MOS capacitors using a cyclotron microbeam

As overlayers on electronic devices become progressively thicker, radiation effects microscopy using traditional microbeams (with ion energies up to a few tens of MeVs) is becoming less and less viable. To penetrate to the sensitive regions of these devices, much higher energies, several hundreds of MeVs are necessary. These high energies are available only from cyclotrons. A nuclear microprobe has been developed on the AVF cyclotron of the Takasaki Ion Accelerators for Advanced Radiation Applications (TIARA) facility. In this paper we will present the first results using 260 MeV Ne and 520 MeV Ar microbeams to perform Time Resolved Ion Beam Induced Current (TRIBIC) measurements on Metal-Oxide-Semiconductor (MOS) capacitors. The results will be compared to data taken with a traditional 15 MeV O microbeam.     

Preparation of carbon alloy catalysts for polymer electrolyte fuel cells from nitrogen-containing rigid-rod polymers

‘Carbon Alloy Catalysts’ (CAC), non-precious metal catalysts for the oxygen reduction reaction (ORR), were prepared from various kinds of nitrogen-containing rigid-rod aromatic polymers, polyimides, polyamides and azoles, by carbonization at 900 °C under nitrogen flow. The catalytic activity for ORR was evaluated by the onset potential, which was taken at a current density of −2 μA cm⁻². Carbonized polymers having high nitrogen content showed higher onset potential. In particular, CACs derived from azole (Az5) had an onset potential of 0.8 V, despite being was prepared without any metals.     

Promoting Effect of Basic Fibroblast Growth Factor in Synovial Mesenchymal Stem Cell-Based Cartilage Regeneration

Synovial mesenchymal stem cell (SMSC) is the promising cell source of cartilage regeneration but has several issues to overcome such as limited cell proliferation and heterogeneity of cartilage regeneration ability. Previous reports demonstrated that basic fibroblast growth factor (bFGF) can promote proliferation and cartilage differentiation potential of MSCs in vitro, although no reports show its beneficial effect in vivo. The purpose of this study is to investigate the promoting effect of bFGF on cartilage regeneration using human SMSC in vivo. SMSCs were cultured with or without bFGF in a growth medium, and 2 × 10⁵ cells were aggregated to form a synovial pellet. Synovial pellets were implanted into osteochondral defects induced in the femoral trochlea of severe combined immunodeficient mice, and histological evaluation was performed after eight weeks. The presence of implanted SMSCs was confirmed by the observation of human vimentin immunostaining-positive cells. Interestingly, broad lacunae structures and cartilage substrate stained by Safranin-O were observed only in the bFGF (+) group. The bFGF (+) group had significantly higher O’Driscoll scores in the cartilage repair than the bFGF (−) group. The addition of bFGF to SMSC growth culture may be a useful treatment option to promote cartilage regeneration in vivo.     

Synthesis of Polyaniline/Pd Nanoparticles via Ligand Exchange

Polyaniline/Pd nanoparticles were synthesized via ligand exchange. Pre-prepared water soluble starch/Pd nanoparticles were treated with polyaniline, and washed with water, leading to the small and well-dispersed polyaniline/Pd nanoparticles. The redox state of polyaniline was preserved during the ligand exchange reaction.

Substitutional reaction in Si–O network of molecular dynamics-modeled liquid Na2SiO3: Microscopic and statistical study

The study of the bond breaking and formation processes, that is, the chemical reaction, in the Si–O network structure in liquid alkali silicates at temperatures around or higher than the glass-transition temperature is important for understanding kinetic processes such as the structural relaxation of the network, viscous flow, and diffusion of the network former ions. Herein, novel methods for analyzing the reactions in a molecular-dynamics-modeled liquid Na₂SiO₃ were used to confirm the following results: (a) the substitutional reactions (in which a nonbridging O ion of a Si–O chain or a SiO₄ tetrahedron attacks the Si ion of another chain from backside of a bridging O ion, which acts as the leaving group, and the bridging O leaves the Si ion) primarily occur in the Si–O network of liquid Na₂SiO₃; and (b) The abundance ratio of Q_n species can be quantitatively reproduced by the reaction rate.     

Wireless Measurement System for Ground-borne Vibration and Vibration Amplifications in Buildings

The environmental impact on residents of buildings, such as adverse effect on sleep and physical discomfort is caused by ground-borne vibration sources such as rail transit systems, road traffic, construction sites, and industrial plants. To estimate the impact of these vibrations on the residents, it is necessary to measure the tri-axial vibrations in the vertical and horizontal directions of the buildings as specified in the international standard regulated by ISO 2631-2:2003. A wireless measurement system for simple and accurate measurement of building vibration was developed. Five wireless vibration measurement devices (installed together with a data recorder in the building) are controlled simultaneously by an outdoor mobile PC or a laboratory PC via wireless local area network and an Internet connection. It sends the vibration acceleration waveforms recorded in buildings over the wider internet communication system to the laboratory PC. The wireless measurement system was used for measuring vibration in two- and three-story detached houses of wooden or steel construction. The impact on the residents may be caused by the vibration amplifications associated with building structural resonances. The vibration amplifications in 120 houses were evaluated as ratios and level differences in 1/3 octave band vibration accelerations measured at the ground near the substructure and floors.     

Optimum budget allocation method for projects with critical risks

In this paper, the authors analyze the trade-off problem between project budgets and critical risks. Project managers face the problem to balance cash flows and risks when preventive risk response plans require additional costs. Mathematical modeling approach is used with a metric called risk-based project value (RPV). RPV is an evaluation of projects calculated with cash flows and risk probabilities of activities that constitute the project network diagram. There exists an optimal solution for the budget allocation problem that maximizes the expected project value. There is a condition where additional budgets can improve the project value. The study result suggests that there should be an integrated process to optimize the budget plan with the risk management plan. Methods are developed to obtain optimum budget allocations for projects with various types of activity networks. Evaluation of the marginal cost sensitivity on the RPV supports project manager's decisions on reallocation of budgets.     

Total androgen blockade--concept, theory, method and clinical application

There can be seen many investigations to examine the effects and benefits of total androgen blockade (TAB), combining an antiandrogen with surgical castration or a LH-RH analogue, for advanced prostate cancer. This review summarizes the concept, theory, method and clinical application of TAB. The concept of TAB was supported by reports that show a survival advantage using the combined blockade over LH-RH analogue alone. The theory of TAB proposes that suppression of all androgen production, adrenal and testicular androgen, should result in a better response than standard hormonal management such as castration and/or estrogens. In Japan, Chlormadinone acetate (100 mg twice daily) or Flutamide (375 mg three times daily) is orally administered and Leuprorelin acetate (3.75 mg every 4 weeks) or Goserelin acetate (3.6 mg every 4 weeks) is administered by hypodermic injection. There have been unresolved controversies surrounding this therapeutic modality, therefore future studies should help to define the role of TAB.