Tensile Strength of Yttria-Stabilized Tetragonal Zirconia Polycrystals

Tensile strengths of 2.0 to 5.0 mol% Y₂O₃-stabilized ZrO₂ polycrystals were described using the newly developed tensile testing method. The tensile test was conducted by attaching three strain gauges on both sides of a rectangular bar that was 10 mm by 1 mm by 200 mm. The tensile strength of tetragonal ZrO₂ polycrystals (TZP) containing 2.0 mol% Y₂O₃ showed 745 MPa, whereas the bend strength of this material was 1630 MPa. Inelastic behavior of the stress-strain curve was observed at critical stresses and strains of 500 to 700 MPa and 0.25% to 0.35%, respectively. Although deviation from proportionality was observed to be small, it increased with the increase of temperature from −100° to 200°C.     

Conversion of chemical into mechanical energy by contractile polymers performed by polymer complexation

A mechanochemical energy conversion system working upon polymer-polymer complexation between poly(methacrylic acid) (PMAA) and poly(ethylene glycol) (PEG) was studied. It was found that among PEGs of various molecular weights used, PEG with molecular weight of 2000 provided the most rapid and significant contraction of crosslinked PMAA membrane loaded 100 times the weight of dry membrane, exhibiting about 2000 g/cm² of stress. Increasing and decreasing the molecular weight of PEG from 2000 brought about gradual decrease both in the contraction and stress of the membrane. The work done per contraction per gramme of contractile substance was studied for various loads. It was found that the work done increased linearly with increasing weight of load, reaching 200 g cm.     

Intention-Sensing Recipe Guidance via User Accessing to Objects

Sensing the intention of a user’s forthcoming action is a necessary function for systems that assist human physical activity. In this article, a strategy for recipe guidance systems that can predict the forthcoming intended subtask in a cooking task is investigated. The focus is on user accessing objects, that is, touching and releasing objects. Touching can indicate the start of the forthcoming subtask and releasing can indicate the end of the task. The main difficulty lies in the fact that humans may move objects because they are in the way and use cooking tools that are unanticipated by an assistive system. In such cases, the accessed object should not indicate the forthcoming subtask. A method is proposed to track the progress of a task based on the object access history. This enables to eliminate object accesses that are out of context. Simultaneously, the method predicts the forthcoming subtask based on a combination of progress and materials rather than tools and materials. Then, a guidance system that runs as a web service is developed. In experiments, real cooking activities navigated by this system are observed. The Wizard of OZ method is utilized to simulate a system that detects object accesses. The experimental results show that 73.6% accuracy is achieved in the selection of the displayed information. This result supports the use of “access to objects” realize effective intention-sensing systems.     

Removal of arsenic from groundwater by arsenite-oxidizing bacteria

The presence of arsenic in groundwater has been of great public concern because of its high toxicity. For purification of arsenic-contaminated groundwater, bacterial oxidation of arsenite, As(III), with a chemical adsorption process was examined in this study. After As(III) oxidation to arsenate, As(V), arsenic is easily removable from contaminated groundwater because As(V) is more adsorptive to absorbents than As(III). By acclimation to As(III) of high concentrations, a mixed culture of heterotrophic bacteria with high As(III)-oxidizing activity was obtained from a soil sample that was free from contamination. With initial concentration up to 1,500 mg l(-1) As(III), the mixed culture showed high As(III)-oxidizing activity at pH values of 7-10 and at temperatures of 25-35 degrees C. The mixed culture contained several genera of heterotrophic As(III)-oxidizing and arsenic-tolerant bacteria: Haemophilus, Micrococcus, and Bacillus. Activated alumina was added to the basal salt medium containing 75 mg l(-1) As(III) before and after bacterial oxidation. Arsenic removal by activated alumina was greatly enhanced by bacterial oxidation of As(III) to As(V). The isotherms of As(III) and As(V) onto activated alumina verified that bacterial As(III) oxidation is a helpful pretreatment process for the conventional adsorption process for arsenic removal.     

Technology development for roll-to-roll production of organic photovoltaics

In order to reach the objective of low-cost, large area organic photovoltaic systems, we build up a knowledge base concerning the influence of process conditions on the performance of polymer solar cells. A large area solar cell module, with roll-to-roll coated PEDOT:PSS and photoactive layers (based on P3HT:[C60]PCBM blend) on a flexible substrate, has been demonstrated. Both the PEDOT:PSS and photoactive layer were deposited by slot die coating. A non-chlorinated solvent was used for the deposition of the photoactive blend. The flexible solar cell module illustrated a power conversion efficiency of 0.7% under AM 1.5 conditions. Methods to further improve the technological process are proposed.     

Cloning,sequencing and expression analysis of a gene encoding alcohol oxidase in Paenibacillus sp. AIU 311

We have cloned a gene encoding an alcohol oxidase (AOD) specific to aldehyde alcohols from Paenibacillus sp. AIU 311. The AOD gene contains an open reading frame consisting of 618 nucleotides corresponding to 205 amino acid residues. The deduced amino acid sequence exhibits a high similarity to that of manganese superoxide dismutases (SODs). We expressed the cloned gene as an active product in Escherichia coli BL21 cells. The productivity (total units per culture broth volume) of the recombinant AOD expressed in E. coli BL21 is 26,000-fold higher than that of AOD in Paenibacillus sp. AIU 311. The recombinant AOD also exhibits aldehyde alcohol oxidase activity and SOD activity. The recombinant cells described in this study have utility for the production of glyoxal from glycolaldehyde.     

Application of real-time polymerase chain reaction (PCR) coupled with ethidium monoazide treatment for selective quantification of viable bacteria in aquatic environment

Ethidium monoazide (EMA) was used to quantify DNA selectively from viable cells with healthy membrane/cell wall system, but not from dead cells, of a target bacterium in the aquatic environment using real-time PCR. Spiking experiments to determine the EMA treatment conditions showed that EMA treatment with EMA at 10-25 microg/ml and subsequent halogen light exposure for 2 min was suitable for selective quantification of DNA from viable cells in an aquatic sample using real-time PCR coupled with EMA treatment (real-time EMA-PCR). Optimized real-time EMA-PCR was applied in combination with culture-based method and conventional real-time PCR without EMA treatment to elucidate the behavior of an Escherichia coli strain inoculated into a pond water microcosm. Quantification results obtained using real-time EMA-PCR were lower than those by conventional real-time PCR without EMA treatment and higher than those by culture-based method. The results suggest that quantification by real-time EMA-PCR seemed to represent the viable population, which would partly include viable but non-culturable state bacteria. Real-time EMA-PCR optimized here can be a useful tool for selective monitoring of the viable population of a target bacterium in the aquatic environment, and thereby contribute to assessment of potential microbial risks generated from waterborne pathogenic bacteria.     

フライアッシュを用いたコンクリ一トの中性化に及ぼす暴露条件の影響

本報告はフライアッシュを使用したコンクリートの中性化についての測定結果を取りまとめたものである.シリーズⅠでは、暴露地、フライアッシュの種類、置換率における比較を行った.シリーズⅡでは、供試体の向き、設置場所、設置条件、調合条件における比較を行った.その結果、シリーズⅠにおいては、屋外暴露の場合、地域による中性化の差はあまり見られず、屋内と屋外の中性化速度係数の比は既往の実態調査結果より小さくなり、また、同一水結合材比では、フライアッシュの種類による中性化の差は認められなかった.シリーズⅡでは、中性化速度係数は屋外に置いて屋根なしより屋根ありのほうが大きい値を示し、また、建物の南側より北側のほうが小さい値となった.     

Vancomycin resistant enterococci

Enterococci are normal intestinal flora in humans. Among enterococci, Enterococcus faecalis and Enterococcus faecium are frequently isolated and can become nosocomial pathogens in hospitals, especially in intensive care units and oncology wards. Recently, vancomycin-resistant enterococci (VRE) such as E. faecalis and E. faecium have caused a serious problem of hospital-acquired infections in Europe and the USA. VRE also has another aspect as a cause of community-acquired infections. Especially, avoparcin which had been used to enhance growth of food animals is documented as associated with the spread of VRE in European countries. In Japan, there have only been a few of reports about VRE so far. However, there evidence that VRE might become prevalent in many hospitals in Japan. In fact, we have already isolated another highly vancomycin-resistant E. faecium (VCM:MIC > 128 micrograms/ml) from a hospitalized diabetic patient. We should pay a careful attention to VRE and perform the following control measures: 1)re-education and re-training about hospital infection control procedures, 2) prudent use of vancomycin in clinical settings, 3)accurate report of VRE in clinical laboratories, and 4) good communications and collaborations among physicians, nurses and other health care personnel and laboratory technicians. We should learn more from countries in which VRE are already prevalent, and pursue further investigations, to prevent the spread of VRE in Japan.