Octacalcium phosphate (OCP) is resorbable bone regenerative material, but its brittleness makes it difficult to maintain its shape without restraint. We have engineered a scaffold constructed of synthetic OCP and porcine collagen sponge (OCP/Collagen) and investigated whether OCP/Collagen composite could improve bone regeneration. To examine this hypothesis, bone regeneration by the implantation of OCP/Collagen was compared with those by OCP and collagen. Radiographic and histological examination was performed and the percentage of newly formed bone (n-Bone%) in the defect was determined by a histomorphometrical analysis. OCP/Collagen, OCP, or collagen was implanted into the critical-sized defects in rat crania and fixed at 2, 4, or 8 weeks after implantation. OCP/Collagen improved the handling performance than the granules of OCP, and synergistically enhanced the bone regeneration beyond expectation, which were composed of bone nucleation by OCP and cell infiltration by collagen. Histomorphometrical analysis showed that n-Bone% +/- standard error treated with OCP/Collagen (48.4 +/- 5.14) was significantly higher than those with OCP (27.6 +/- 4.04) or collagen (27.4 +/- 5.69) in week 8. The present study suggests that the combination OCP with collagen elicited the synergistic effect for bone regeneration.

The characteristics of electrochemically produced polyaniline as the active material of secondary batteries were studied in aqueous electrolytes. The cell of the type, normalZn/1M ZnSO4/normalpolyaniline , has the maximum capacity of 108 Ah/kg and the energy density of 111 Wh/kg. The coulombic efficiency was close to 100% over at least 2000 complete cycles when cycled between 1.35V and 0.75V at a constant current of 1 mA cm−2. The normalpolyaniline/4M H2SO4/PbO2 cell, where polyaniline was used as the anode, also showed excellent recyclability. The effect of oxygen and of the exposure to high anodic potential to the characteristics of polyaniline electrodes was also studied.

It is argued that the diffeomorphism on the horizontal sphere can be regarded as a nontrivial asymptotic isometry of the Schwarzschild black hole. We propose a new boundary condition of asymptotic metrics near the horizon and show that the condition admits the local time-shift and diffeomorphism on the horizon as the asymptotic symmetry.

duction path. Without such an elaborate chemical modification, some progress might be possible by using regular enzymes, with required coenzymes, in a mixed conducting suspension of a material such as NMPTCNQ. Progress might include long lifetime, freedom from covering membrane, and possible increased amplification, compared with the now conventional enzyme-catalyzed amperometric sensors. ConclusionsPlasticizing NMPTCNQ with DIBP reduces its electronic conduction linearly, with an extrapolated specific conductivity of 0.1 S/cm at zero plasticizer content. At very high DIBP levels, the electronic conductivity is so low that it is comparable with the apparent ionic component, estimated experimentally at 10-6-10 -7 S/cm. NMPTCNQ/DIBP mixtures are quite stable and ohmic at low voltages, using electronic contacts, except for very high DIBP contents when electric fields may change the orientation of NMPTCNQ particles.Simple redox reagents: copper(II, I, 0) and ferro-/ferricyanide retain electroactivity on plasticized NMPTCNQ coatings on glassy carbon electrodes, and demonstrated the possibility of using suspensions to mediate and promote enzyme/substrate/surface reactions.

Previous studies have shown that synthetic octacalcium phosphate (OCP) facilitates in vitro osteoblastic cell differentiation in an OCP dose-dependent manner and that a complex of OCP and collagen (OCP/collagen) enhances critical-sized rat calvaria defects more than OCP alone. The present study was designed to investigate whether the bone regenerative properties of OCP/collagen are augmented in an OCP dose-dependent manner, thereby establishing a suitable composition of this composite as a bone substitute material. OCP/collagens with a wide range of mixing ratios from 23:77 to 83:17, including the previously examined composition (77:23), were prepared by blending granules of OCP with atelocollagen and molded into a disk as an implant. A critical-sized defect was made in rat calvaria, and each disk was implanted into the defect for 4 or 12 weeks and then examined radiographically, histologically, and histomorphometrically. Mouse bone marrow-derived stromal ST-2 cells were cultured in dishes pre-coated with OCP/collagen or OCP alone with different OCP contents to determine the capacity of cell attachment and proliferation up to 14 days. Histological and radiographic examinations showed that newly formed bone was observed in relation to OCP granules within the collagen matrix. Histomorphometric analysis confirmed that increasing the amount of OCP in collagen matrices resulted in progressive enhancement of bone regeneration and that the ratio 83:17 generated the maximum repair level of approximately 64% of the defect at 12 weeks. OCP/collagen promoted the proliferation and attachment of ST-2 cells more than OCP alone regardless of OCP content. Fourier transform infrared spectroscopy analysis of the coatings after the incubation indicated that OCP tended to convert to apatite regardless of the presence of collagen. The present study demonstrated that the osteoconductive characteristics of OCP/collagen can be displayed in an OCP dose-dependent manner. The results suggest that collagen promotes the proliferation and attachment of host osteoblastic cells on OCP/collagen composite implants.

We have engineered a scaffold constructed of synthetic octacalcium phosphate (OCP) and porcine collagen sponge (OCP/Col), and reported that OCP/Col drastically enhanced bone regeneration. In this study, we investigated whether OCP/Col would enhance bone regeneration more than beta-tricalcium phosphate (beta-TCP) collagen composite (beta-TCP/Col) or hydroxyapatite (HA) collagen composite (HA/Col). Discs of OCP/Col, beta-TCP/Col, or HA/Col were implanted into critical-sized defects in rat crania and fixed at 4 or 12 weeks after implantation. The newly formed bone and the remaining granules of implants in the defect were determined by histomorphometrical analysis, and radiographic and histological examinations were performed. Statistical analysis showed that the newly formed bone by the implantation of OCP/Col was significantly more than that of beta-TCP/Col or HA/Col. In contrast, the remaining granules in OCP/Col were significantly lower than those in beta-TCP/Col or HA/Col. Bone regeneration by OCP/Col was based on secured calcified collagen and bone nucleation by OCP, whereas bone regeneration by beta-TCP/Col or HA/Col was initiated by poorly calcified collagen and osteoconductivity by beta-TCP or HA. This study showed that the implantation of OCP/Col in a rat cranial defect enhanced more bone regeneration than beta-TCP/Col and HA/Col.

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Basic behaviors and properties of polyaniline(PA) deposited anodically on platinum electrodes have been studied on the following points. 1) Effect of the mode of electrolysis and supporting electrolytes in the film forming process. 2) Characteristics of charging-discharging processes. 3) Electric conductivity and elemental composition of PA. The different modes of electrolysis do not affect the characteristics of the PA electrode obtained. The growth rate of PA film is 2.7–2.8 times faster in sulfuric acid than in perchloric, nitric or hydrochloric acid. It is indicated that there are two types of doping; one is associated with the acid-base equilibrium between amino or imino group in the film and proton in the solution and the other is associated with the excess charge in the film produced by anodic oxidation. The electric conductivity of PA markedly decreases by the immersion in alkali solutions. The release of doped anion from PA by treating with an alkali solution is confirmed by the elemental analysis. The amount of anions occluded by the electrochemical doping process is determined to be 0.25–0.29 per monomer unit.