Osteoinduction by Functionally Graded Apatites of Bovine Origin Loaded with Bone Morphogenetic Protein-2

Bioresorbable and functionally graded apatites (fg-HAp) ceramics, which are characterized by gradations in crystallinity and the grain size of hydroxyapatite (HAp:Ca₁₀(PO₄)₆(OH)₂), were designed using bovine bone by the calcination and partial dissolution–precipitation method. The fg-HAp ceramics had macropores of 100–600 μm originated from spongy bone, and micropores of 10–160 nm. Fg-HAp ceramics loaded with recombinant human bone morphogenetic protein-2 (rhBMP-2/fg-HAp) were implanted into the subcutaneous tissue of rats. Eight weeks after the implantation, the surface and bulk degradations of the fg-HAp-containing body fluid occured, and small pieces of fg-HAp were incorporated into the induced bone and fatty marrow, suggesting that osteoinduction occurred in conjunction with bone remodeling. The rhBMP-2/fg-HAp ceramics developed could become a resorbable biomimetic material with fast bioresorption and osteoinduction characteristics.     

Low Frequency Pulsed Resonant Converter for Energy Harvesting

A pulsed-resonant ac-dc converter and an integrated circuit (IC) controller have been designed, fabricated, and tested for harvesting energy from low-voltage (1.2V), low-power (1-100muW) energy transducers with output frequency in the 10-Hz-1-kHz range. Simulations using foundry models suggest that the silicon loss could be as low as 0.6muW, and the efficiency could reach 70%. With the IC experimentally packaged, the measured efficiency is between 50% and 70%, depending on the size and the loss in the resonant inductor     

Synthesis and characterization of fluorene-carbazole and fluorene-phenothiazine copolymers with carbazole and oxadiazole pendants for organic light emitting diodes

We report the synthesis and characterization of new series of the fluorene based polymers with carbazole and oxadiazole pendants for the generation of the white emission out of the EL device. In the fluorene backbone, hole transporting units such as carbazole or phenothiazine were incorporated to improve the EL brightness and efficiency. The PFCzOxd-co-PCzs and PFCzOxd-co-PPTZs in EL spectra showed maximum peaks at around 430 nm and additional large peaks at around 530 and 500 nm, respectively. In case of PFCzOxd-alt-PCz and PFCzCzPCz-co-PFOxdOxdPCz, the EL spectra of the polymers showed two distinct peaks comprising the maximum at 427 nm, which corresponds to the EL spectra of the conjugated backbone, and additional broad peaks at around 540 and 530 nm, respectively. The CIE coordinates of the devices from PFCzOxd-alt-PCz and PFCzCzPCz-co-PFOxdOxdPCz were (0.28, 0.33) and (0.25, 0.32), respectively, approaching the value of the standard white of National Television System Committee (NTSC) (0.33, 0.33).     

Structural estimation of particle arrays at air–water interface based on silica particles with well‐defined and highly grafted poly(methyl methacrylate)

Silica nanoparticles with well‐defined, highly grafted dense poly(methyl methacrylate) (MMA) were prepared by surface‐initiated activators regenerated by electron transfer for atom transfer radical polymerization (ARGET ATRP) of methyl methacrylate with an initiator‐fixed silica particle in the presence of air. Two different polymerizations of MMA were carried out under the same conditions using tris[2‐(dimethylamino)ethyl]amine (Me₆TREN) and N,N,N′,N′,N″‐pentamethyldiethylene‐triamine (PMDETA) as the ligand, respectively. In the CuCl₂/PMDETA system, polymerization appeared to be more controlled with a lower polydisperisty compared with the CuCl₂/Me₆TREN system. The monolayer of these particles was formed at the air–water interface using Langmuir‐Blodgett (LB) technique. Multilayers of the particles were fabricated by repetition of LB depositing. A surface pressure–area (π–A) measurement and SEM observation were used to characterize the particle arrays. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers     

Six types of spherulite morphologies with polymorphic crystals in poly(heptamethylene terephthalate)

Six types of spherulite morphologies packed with polymorphic crystals and their growth kinetics in melt-crystallized poly(heptamethylene terephthalate) (PHepT) were characterized using polarized-light optical microscopy (POM), Fourier transformed infrared microspectrometry (micro-FTIR), differential scanning calorimetry (DSC) and atomic-force microscopy (AFM). Two maximum melting temperatures (T_max), a higher 150 °C and a lower 110 °C, were used to melt the initially crystallized PHepT of either α- or β-crystal. The high T_max was enough to melt all nuclei, but the lower T_max was considered as near or slightly below the equilibrium melting temperatures of these two cells (if estimated by nonlinear methods). When crystallized at various T_c from these two T_max’s, PHepT can exhibit as many as six types of spherulites (Ring Type-I, -II, -III, Maltese-cross Type-1, -2, and -3) owing to different nucleations. Ring Type-I, Maltese-cross Type-1 and -3 spherulites are packed of the sole β-crystal, while Ring Type-II, -III and Maltese-cross Type-2 spherulites are attributed to the sole α-crystal. However, as the PHepT polymorphic cells are related to T_c, such correlations between the crystal cells and spherulite types (ring or ringless) cannot be ruled out to be a coincidence.     

Continuous‐Flow C?H Borylation of Arene Derivatives

A new continuous‐flow system for C H borylation has been developed. An insoluble catalyst prepared from chloro(1,5‐cyclooctadien)iridium(I) dimer and 2,2′‐bipyridine‐4,4′‐dicarboxylic acid in the presence of bis(pinacolato)diboron exhibited high reactivity under continuous‐flow processing without the loss of expensive iridium metal.     

Preparation and biological evaluation of hydroxyapatite-coated nickel-free high-nitrogen stainless steel

Calcium phosphate was formed on nickel-free high-nitrogen stainless steel (HNS) by chemical solution deposition. The calcium phosphate deposition was enhanced by glutamic acid covalently immobilized on the surface of HNS with trisuccinimidyl citrate as a linker. X-ray diffraction patterns and Fourier transform infrared spectra showed that the material deposited on glutamic acid-immobilized HNS within 24 h was low-crystallinity calcium-deficient carbonate-containing hydroxyapatite (HAp). The biological activity of the resulting HAp-coated HNS was investigated by using a human osteoblast-like MG-63 cell culture. The HAp-coated HNS stimulated the alkaline-phosphate activity of the MG-63 culture after 7 days. Therefore, HAp-coated HNS is suitable for orthopedic devices and soft tissue adhesion materials.     

Fabrication of high‐strength steel fibre reinforced metal matrix composites by explosive bonding and their tensile properties

Summary

Steel fibre reinforced metal matrix composites (FRM) consisting of high‐strength ductile steel wire and aluminium or titanium foil were fabricated by explosive bonding. The strength properties were evaluated by tensile tests. The optimum explosive loading (explosive mass/driver plate mass) increases with the volume fraction of fibre. For the aluminium matrix composites, the micrographs obtained show sound bonding between the adjoining foils and non‐bonding between the foil and steel wire. The tensile strength of the aluminium matrix composites is 80% of the value predicted by the rule of mixtures. For the titanium matrix composites, the micrographs obtained show both bonded and unbonded regions between the adjoining foils or between the foil and steel wire. The tensile strength of the titanium matrix composites agrees with the value predicted by the rule of mixtures.     

Automatic Train Operation Using Autonomic Prediction of Train Runs

In this paper, we present an automatic train control method adaptable to disturbed train traffic conditions. The proposed method presumes transmission of detected time of a home track clearance to trains approaching the station by employing equipment of Digital ATC (Automatic Train Control). Using the information, each train controls its acceleration by a method that consists of two approaches. First, by setting a designated restricted speed, the train controls its running time to arrive at the next station in accordance with predicted delay. Second, the train predicts the time at which it will reach the current braking profile generated by Digital ATC, along with the time when the braking profile transits ahead. By comparing them, the train correctly chooses the coasting drive mode in advance to avoid deceleration due to the current braking profile. We evaluated the effectiveness of the proposed method regarding driving conditions, energy consumption, and reduction of delays by simulation. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 175(3): 65–73, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.10020/eej.21080