Graphene etching controlled by atomic structures on the substrate surface

We etched graphene on a sapphire (1 ?1 0 2) surface using the reaction between graphene and hydrogen catalyzed by metal nanoparticles. To investigate effects of the atomic structure of the sapphire substrate on graphene etching, we used sapphire substrate with as-polished, air-annealed, and step-ordered surfaces. We investigated the relationship between the atomic arrangement of sapphire and graphene etching and found that graphene is selectively etched in the [1 ?1 0 ?1] direction of sapphire. This indicates that atomic structure of the sapphire surface can be used as a template to control graphene etching. By combining the transfer method for graphene sheets grown on metal substrates with the present etching technique, graphene nanoribbons can be fabricated at a wafer level.     

Purification and characterization of organic solvent-stable protease from organic solvent-tolerant Pseudomonas aeruginosa PST-01

An organic solvent-stable protease (PST-01 protease) in a culture broth of organic solvent-tolerant Pseudomonas aeruginosa PST-01 was purified by successive hydrophobic interaction chromatography using Butyl-Toyopearl gels. The purified enzyme was homogeneous as determined by SDS-polyacrylamide gel electrophoresis. PST-01 protease had a molecular mass of 38 kDa. The optimum temperature and pH for casein hydrolysis were 55 degrees C and 8.5, respectively. PST-01 protease was stable at pH 8-12 and below 50 degrees C and was determined to be a metalloprotease which was inhibited by EDTA, 1,10-phenanthroline, and phosphoramidon. PST-01 protease inhibited by EDTA was reactivated completely by the addition of zinc or cobalt ions. The stability of PST-01 protease in solutions containing water-soluble organic solvents or alcohols was higher than that in the absence of organic solvent. Furthermore, in general, PST-01 protease was more stable than commercially available proteases, namely, subtilisin Carlsberg, thermolysin, and alpha-chymotrypsin, in the presence of water-soluble organic solvents or alcohols.     

Effect of metabolic substrate on BMIPP metabolism in canine myocardium

The lipid tracer 1 5-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (BMIPP) is clinically useful, and its basic metabolism is being analyzed. Because the pharmacokinetics of this lipid tracer may be affected by blood concentrations of fatty acid or glucose, this study evaluated the effects of excess levels of lipid or glucose on BMIPP uptake and metabolism. METHODS: A technique using an open-chest dog model was used. Blood sampling was performed from the left anterior descending coronary artery and great cardiac vein after an injection of 123I-BMIPP either with a glucose infusion (n = 6) or a lipid infusion (n = 5). High performance liquid chromatography and double-tracer kinetic analyses clarified the extraction, retention, backdiffusion and further metabolism of BMIPP. These results were compared with data from control dogs (n = 6). RESULTS: In this experiment, a 10-fold increase over the normal lipid blood concentration and twofold increase over the normal blood glucose concentration were evaluated with either intralipid or glucose infusion, respectively. In the lipid infusion studies, the extraction significantly decreased compared with the control values (74% +/- 12% to 58% +/- 8%; p < 0.05), and the washout increased from 50% +/- 13% to 68% +/- 16% (p < 0.05). The BMIPP backdiffusion increased (p < 0.05), and the levels of the further metabolites decreased (p < 0.05), while the retention level remained constant (normal, 89% +/- 9%; lipid infusion, 91% +/- 3%; ns). In the glucose infusion studies, the BMIPP extraction, retention and washout showed no statistical differences compared to controls; however, these parameters showed the same tendencies as those in the lipid infusion group. In addition, the BMIPP backdiffusion increased significantly (control, 25.1% +/- 8%; glucose infusion, 48.7% +/- 25.6%; p < 0.05) as it did after the lipid infusion. CONCLUSION: BMIPP metabolism and uptake are affected by excess concentrations of lipid and glucose in the blood. However, the retention of BMIPP was not affected by either type of infusion. The BMIPP backdiffusion and the further metabolite comprising 10% of the tracer extracted were affected both by the lipid and glucose infusions. These results indicate that an excess fat concentration and glucose affect BMIPP uptake, especially the extraction of BMIPP and BMIPP backdiffusion.     

Synthesis of polymers for hole and electron transport materials inorganic electroluminescent devices

Styrene-type polymers having tetraphenylbenzidine (TPD) or tetraphenylphenyldiaminobenzene unit (PDA) and a oxadiazole unit (PBD) on the side chain were prepared as hole and electron transport materials, respectively, of an electroluminescent (EL) device. The device structures employed were [indium-tin-oxide (ITO)/hole transport layer (HTL)/Al] (type I), or [ITO/hole transport layer (HTL)/electron transport layer (ETL)/Al] (type II). Type I devices provided current density higher than 100 mA/cm² but no luminescence was observed. Type II devices emitted luminescence of about 10 cd/m² at the current density of about 170 mA/cm². The emission maximums of these devices were 460 and 530 nm for the device using TPD and PDA, respectively     

Indentation creep in nanocrystalline Fe-TiN and Ni-TiN alloys prepared by mechanical alloying

Mechanical properties of nanocrystalline Fe-TiN and Ni-TiN alloys with various TiN contents between 17 and 64 vol pct, which are prepared by dynamically consolidating mechanically alloyed powders, have been investigated by means of hardness measurements and indentation creep tests at intermediate temperatures. The hardness increases with decreasing grain size to about 10 nm. The indentation creep curves conform well to an equation derived from a transient creep rate equation. The analysis of creep curves indicates that the deformation occurs by a dislocation mechanism controlled by grain boundary diffusion.     

Replication of cyclobutane pyrimidine dimer analogue by Ex Taq DNA polymerase

We previously reported an efficient and reversible template-directed photoligation using 5-carboxyvinyl-2′-deoxyuridine (^CVU)-containing ODN at the 5′-terminal. This method forms d(T-^CVU) as a cyclobutane pyrimidine dimer (CPD) analogue between the 3′-terminal thymidine and the 5′-terminal ^CVU of two oligodeoxynucleotides (ODNs). In this study, we performed PCR using a DNA template containing d(T-^CVU). Then, we found that two adenines were incorporated opposite the d(T-^CVU).     

Studies on the catalysis of molten metal. 13. Kinetics of dehydrogenation of tetralin over molten tellurium catalyst

In a study of the thermal decomposition of tetralin, the rates of pyrolysis and of catalysed decomposition over molten tellurium or in the presence of tellurium vapour have been measured. All rate processes examined have been found to obey the first-order irreversible consecutive rate law and to proceed through the following reaction pathway:

Both molten tellurium and tellurium vapour have been found to reduce the activation energy of the step A → B and enhance the frequency of the step B → C. Although the apparent activities of the two catalysts were found to be similar, estimates of the intrinsic activities indicate that the molten tellurium surface is more effective. It is suggested that the number of catalytic sites on the molten tellurium surface is larger than in the tellurium vapour.