New water-soluble metal working fluids additives from phosphonic acid derivatives for aluminum alloy materials

Water-soluble metal working fluids are used for processing of aluminum alloy materials. This short paper describes properties of new additives for water-soluble cutting fluids for aluminum alloy materials. Some alkyldiphosphonic acids were prepared with known method. Amine salts of these phosphonic acids showed anti-corrosion property for aluminum alloy materials. However, they have no hard water tolerance. Monoesters of octylphosphonic acid were prepared by the reaction of octylphosphonic acid dichloride with various alcohols in the presence of triethylamine. Amine salts of monoester of octylphosphonic acid with diethyleneglycol monomethyl ether, ethyleneglycol monomethyl ether and triethyleneglycol monomethyl ether showed both of a good anti-corrosion property for aluminum alloy materials and hard water tolerance.     

Random exchanges of non-conserved amino acid residues among four parental termite cellulases by family shuffling improved thermostability

There have been two major problems preventing applications of termite cellulases; one was difficulty for their hetelologous overexpression, and another is their low thermostability. We previously achieved adaptation of termite cellulase genes to an overexpression system of Escherichia coli by family shuffling of four orthologous cDNAs (Biosci. Biotechnol. Biochem., 2005; 69: 1711-1720). Using the adapted mutant cDNAs as parental genes combined with native-form cDNAs, we performed further family shuffling and obtained mutant cDNAs, which gave enzymes with improved thermostability. The best-evolved clone (PA68) was improved by 10 degrees C in maximum stability (retaining 90% original activity for 30 min incubation) from the parental enzymes, and kept 54% of its original activity for 150 min at 50 degrees C, whereas the most thermostable enzyme amongst the parents (A18) retained 30% of its original activity. PA68 showed 889 (micromoles of reducing sugars/min/mg of protein) in V(max) and 560 (micromoles of reducing sugars/min/mg of protein) in the specific activity against carboxymethylcellulose, which corresponds to 9.8 and 13.1 times of those of one of the ancestral enzymes rRsEG. In summary, we improved thermostability of the termite cellulase and increased the V(max) value and specific activity by combining only cDNAs encoding enzymes adapted for normal temperatures.     

Degradative capacities and bioaugmentation potential of an anaerobic benzene-degrading bacterium strain DN11

Azoarcus sp. strain DN11 is a denitrifying bacterium capable of benzene degradation under anaerobic conditions. The present study evaluated strain DN11 for its application to bioaugmentation of benzene-contaminated underground aquifers. Strain DN11 could grow on benzene, toluene, m-xylene, and benzoate as the sole carbon and energy sources under nitrate-reducing conditions, although o- and p-xylenes were transformed in the presence of toluene. Phenol was not utilized under anaerobic conditions. Kinetic analysis of anaerobic benzene degradation estimated its apparent affinity and inhibition constants to be 0.82 and 11 microM, respectively. Benzene-contaminated groundwater taken from a former coal-distillation plant site was anaerobically incubated in laboratory bottles and supplemented with either inorganic nutrients (nitrogen, phosphorus, and nitrate) alone, or the nutrients plus strain DN11, showing that benzene was significantly degraded only when DN11 was introduced. Denaturing gradient gel electrophoresis of PCR-amplified 16S rRNA gene fragments, and quantitative PCR revealed that DN11 decreased after benzene was degraded. Following the decrease in DN11 16S rRNA gene fragments corresponding to bacteria related to Owenweeksia hongkongensis and Pelotomaculum isophthalicum, appeared as strong bands, suggesting possible metabolic interactions in anaerobic benzene degradation. Results suggest that DN11 is potentially useful for degrading benzene that contaminates underground aquifers at relatively low concentrations.     

Quantitative measurement of tetrahydromenaquinone-9 in cheese fermented by propionibacteria

Propionibacteria produce tetrahydromenaquinone-9 [MK-9 (4H)] as a major menaquinone (vitamin K₂). This study aimed to determine the MK-9 (4H) concentration in commercial propionibacteria-fermented cheese. The MK-9 (4H) concentration was quantified using an HPLC instrument with a fluorescence detector after postcolumn reduction. Among the various cheese samples, the MK-9 (4H) concentration was highest in Norwegian Jarlsberg cheese, followed by Swiss Emmental cheese. In contrast, the MK-9 (4H) concentrations in Appenzeller or Gruyère cheeses were extremely low or undetected. Likewise, the concentrations in Comte and Raclette cheeses were lower than those in Jarlsberg and Emmental cheeses. In the present study, the MK- 9 (4H) concentration in cheese showed a correlation with the viable propionibacterial cell count and propionate concentration. This implies that the increase in propionibacteria contributed to the generation of MK-9 (4H) in cheese. We presumed, based on these results, that Swiss Emmental and Norwegian Jarlsberg cheeses contain a meaningful amount of vitamin K because of their high MK-9 (4H) concentrations (200 to 650 ng/g).     

Dehydration of d-glucose in high temperature water at pressures up to 80 MPa

Reaction of d-glucose in water to yield 5-hydroxymethylfurfural (5-HMF), 1,2,4-benzenetriol (BTO) and furfural was studied at high temperatures (up to 400 °C) and high pressures (up to 80 MPa) using a continuous flow reactor. Maximum temperature and pressure conditions gave maximum furfural yield. Increasing pressure from 40 to 70 and 80 MPa enhanced dehydration reactions to 5-HMF, but also enhanced hydrolysis of 5-HMF leading to the production of BTO and thus lead to lower yields of 5-HMF (below 10%). Remarkably, the dehydration reaction to 5-HMF and the hydrolysis of 5-HMF were both enhanced by the increase in water density at 400 °C.     

Steam absorption process of water/LiBr system inside vertical small bore pipes

In a previous paper, a numerical model for absorption within vertical pipes was proposed and compared with the experiments. Agreements were good for pipes with an OD 28–15 mm but at 10 mm pipe experiments fell below the predicted values. For smaller diameters, the difference between the surface area of the falling liquid film and that of the outer surface of the pipe is not negligible and the thickness of the liquid film is also not negligible. In this paper a new model is formulated in cylindrical coordinates and experiments using pipes with 9.52 mm and 7 mm OD are done. Smooth pipes and two kinds of internally finned pipes, originally developed and used to enhance the heat transfer characteristics of the evaporator and condenser of a refrigerator using HFC as refrigerant, are tested in the experiments. The absorption performance is enhanced by 30% when compared to the smooth pipes, but the difference between the finned pipes is small. © 2004 Wiley Periodicals, Inc. Heat Trans Asian Res, 34(1): 18–28, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20040     

Local work function control of indium tin oxide by micro-contact printing for electroluminescent devices

We demonstrate here that light emission of an electroluminescent (EL) device was enhanced on chemically modified ITO areas over a patterned ITO anode with a self-assembled monolayer (SAM) of 4-chlorophenylphosphoryl dichloride (ClC₆H₄OPOCl₂: CPPDC) prepared by micro-contact printing (μ-CP). The EL device was fabricated by vapor-depositing a hole transport layer, a light emitting and electron transport layer, and a C₆H₅COOLi/Al bilayer cathode on the patterned ITO anode. The enhanced light emission under lower drive voltages on the modified areas can be interpreted by the increase in the work function of the ITO covered with the SAM measured with a Kelvin probe force microscope (KPFM) and thus the decrease in the hole injection barrier height. In addition, we could demonstrate the much smaller pattern images than the previously reported ones [F. Nüesch, Y. Li, L.J. Rothberg, Appl. Phys. Lett. 75 (1999) 1799] by the use of ink-pads.