Active application of primer acid on acid‐treated enamel: Influence on the bond effectiveness of self‐etch adhesives systems

Aim: Evaluate the composite‐to‐enamel bond after passive or active application of self‐etching primer systems on polished or pre‐etched enamel with phosphoric acid. Materials and Methods: Two self‐etch adhesives systems (SEAS) were used: Clearfil SE Bond and Easy Bond. Third human molars were divided into 8 groups (N = 10). The crown of each tooth was sectioned into halves and the mesial/distal surfaces were used. The adhesives were actively or passively applied on enamel with or without prior phosphoric‐acid etching. Resin composite cylinders were built after adhesive application. After stored in relative humidity for 24 hr/37°C the specimens were subjected to microshear test in universal testing a machine at a crosshead speed of 0.5 mm/minute. The results were analyzed with three‐way ANOVA and the Tukey test. The enamel‐etching pattern was evaluated under SEM. Results: The 2‐step SEAS system presented significantly higher adhesive bond strength means (47.37 MPa) than the 1‐step (36.87 MPa). A poor enamel‐ etching pattern was observed in active mode showing irregular and short resin tags, however there was not compromised the bond strength. Conclusion: Active or passive application produced similar values of bond strength to enamel regardless of enamel pretreatment and type of SEAS.     

Transient current mapping obtained from silicon photodiodes using focused ion microbeams with several hundreds of MeV

Single Event Effects (SEEs) triggered by energetic heavy ions traversing a sensitive parts of electric devices have been studied using high-energy heavy ion microbeams connected with Transient Ion Beam Induced Current (TIBIC) measuring system at the Japan Atomic Energy Agency (JAEA) Takasaki Ion Accelerators for Advanced Radiation Applications (TIARA) facility. In the TIBIC system, SEE for semiconductor device, that is fast charge collection, has been observed in timescales of the order of picoseconds. In this paper, we show successful demonstration of the performance of the system, in which clear images of TIBIC map have been observed for Si pin photodiodes irradiated by 260 MeV ²⁰Ne⁷⁺ and also by 520 MeV ⁴⁰Ar¹⁴⁺ microbeams.     

Applications of microstructures fabricated by proton beam writing to electric-micro filters

Fabrication of high-aspect-ratio microstructures was performed by proton beam writing (PBW) using a microbeam line at Takasaki Ion Accelerators for Advanced Radiation Application (TIARA), JAEA Takasaki, JAPAN. As one of the applications of the high-aspect-ratio structures micro-machined by PBW, we utilized the high-aspect pillars for electric-micro filters of microbes such as Escherichia coli and Yeast based on the dielectrophoretic force. The filter is equipped with high-aspect pillars with a height of ～20 μm and a diameter of ～1 μm on a glass plate. Evaluation of the dielectrophoresis (DEP) device for capturing E. coli and Yeast was made using either observation by optical microscope or photoluminescence (PL) measurements.     

Surface Waves on Superfluid <Superscript>4</Superscript>He Under Reduced Gravity

Superfluid ⁴He was produced on a small jet plane for the first time using a small GM-refrigerator to condense the liquid and a scroll pump to get the superfluid by evaporation. The surface wave on superfluid under 0.5g _E, 0.1g _E and 0.05g _E, together with 2g _E and 1g _E, was successfully examined by an optical method utilizing parabolic flight. Here, g _E is the gravitational constant on the ground. Assuming that only the fundamental mode was excited as determined by the sample cell width, the resonance peak in the frequency domain was well reproduced by the gravity wave with corresponding gravity constant.     

Layered mixed-anion compounds: Epitaxial growth,active function exploration,and device application

Optoelectronic properties and device applications of layered mixed-anion compounds such as oxychalcogenide LaCuOCh (Ch = chalcogen) and oxypnictide LaT_MOPn (T_M = 3d transition metal, Pn = pnicogen) are reviewed. Several distinctive functions have been found in these materials based on our original material exploration concept. Fabrication of high-quality epitaxial films of LaCuOCh leads to clarifying the excellent electrical and optical properties such as high hole mobility of 8 cm²/(V s) and heavy hole doping at >10²¹ cm^?3 in LaCuOSe, and sharp and tunable-wavelength photoluminescence in the solid–solution systems in LaCuOCh. In addition, a room temperature operation of a light-emitting diode is demonstrated using LaCuOSe as a light-emitting layer. These results suggest that the layered oxychalcogenides have potential for light-emitting layers as well as transparent hole-injection layers in organic/inorganic light-emitting diodes. Furthermore, by extending the material system from the copper-based oxychalcogenides to isostructural compounds, transition metal-based oxypnictides LaT_MOP (T_M = Fe, Ni), we have found novel superconductors, LaFeOP and LaNiOP.     

High temperature electrochemical heat pump using water gas shift reaction. Part I: Theoretical considerations

A new electrochemical heat pump using a combination of an electrolytic reaction at lower temperature to absorb low grade thermal energy and a thermochemical reaction at higher temperature to produce more efficient thermal energy is proposed. At a lower temperature, an endothermic reaction which cannot occur thermochemically proceeds with electrolysis. At a higher temperature, an exothermic reaction which is the reverse of the electrolysis reaction occurs thermochemically to produce high grade thermal energy. The water gas shift reaction, CO₂(g) + H₂(g) CO(g) + H₂O(g), in molten carbonate is one possible candidate for the new electrochemical heat pump and can lead to an increase in the temperature of the thermal energy from 1100 to 1200K. A heat pump system using the shift reaction is also considered theoretically.     

Potential reprocessing improvements in the Advanced Fuel Recycle System

From the aspects of economical competitiveness, proliferation resistance, and minimizing waste problems, PNC has proposed an improved recycle concept for the FBR fuel cycle, termed Advanced Fuel Recycle System. Reprocessing in this system is based on the well-known PUREX flowsheet and features a “single cycle Pu/U co-extraction flowsheet” with lower decontamination factor (DF) than that in the conventional process. This feature is practical because of the FBR's low neutronic sensitivity to impurities.

Such a simplified extraction process without purification cycles should substantially reduce not only the number of process components but also the quantities of liquid to be treated in other related processes, so it will lead to the proportional reduction in waste processing, waste itself, and all other related equipments and facilities. This should improve overall economics. One method being examined to further reduce the liquid throughputs and simplify the process is to apply the crystallization technique to dissolver solution.

Overall, with this proposed concept, proliferation resistance will be significantly improved because plutonium is always recovered as a mixture with the uranium and DF of the plutonium product is low.

Reprocessing and fabrication processes are integrated into one fuel cycle plant in this system further contributing to these improvements.     

A quicker preparation method for autologous fibrin glue

To establish a quicker preparation procedure for cryoprecipitate (Cryo) from a patient's autologous plasma, to be used as fibrin glue, we examined the effects of various conditions on the concentrations and yields of coagulation factors in Cryo. Human plasma from healthy volunteers was divided and treated under various freezing, shaking and defrosting conditions. The concentrations of fibrinogen, plasminogen, fibronectin, and factor XIII in Cryo were then measured. Results were as follows: (1) concentrations and yields of plasma components in Cryo obtained from plasma stored at -20 degrees C were significantly higher than those in Cryo from plasma stored at -80 degrees C; (2) shaking at 70 cycles/min during the freezing process had a favorable effect on the concentrations and yields of coagulation factors in the Cryo; (3) a shaking thaw process in a cold water bath was a rapid method for obtaining adequate yields of coagulation factors; (4) shaking in the defrosting process did not affect the yields of coagulation factors. These results indicated that Cryo containing high concentrations of coagulation factors could be prepared easily and rapidly from a patient's autologous plasma (within 4-5 h).     

Factors affecting the oxidative activity of laccase towards biphenyl derivatives in homogeneous aqueous-organic systems

Catalytic oxidation of biphenyl derivatives was investigated using laccase in a homogeneous aqueous-organic system. A thermostable laccase from Trametes sp. showed the highest catalytic activity for the oxidation of 4-hydroxybiphenyl (4-HB) at a reaction temperature of 60 degrees C when dimethylsulfoxide (DMSO) was employed as a co-solvent. Furthermore, the catalytic performance was successfully enhanced by the incorporation of a laccase mediator system (LMS) into the aqueous-DMSO media. The catalytic performance strongly depended on the type of mediator, and the highest activity was observed with 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) as mediator, suggesting the importance of the selection of a suitable mediator. It was verified that this mediator system is applicable to the oxidation of several biphenyl derivatives with hydroxyl groups.