21,694 research outputs found
Enzymatic Kinetics of Solvent-free Esterification with Bio-imprinted Lipase
To avoid the use of compounds that burden the environment, a solvent-free enzymatic reaction was the focus of this study. Investigated were the catalytic activities and kinetics of lipases that were pretreated with carboxylic acids for the solvent-free esterification of propionic acid with isoamyl alcohol. The enhancements of the esterification yields and rates by the bio-imprinting effects of carboxylic acids were observed. We
found no inhibition of isoamyl alcohol on the solvent-free enzymatic esterification, and obtained a large imprinting effect under a largely excessive amount of isoamyl alcohol to propionic acid. From the kinetic analysis, the imprinting of lipases mainly enhanced the catalytic reaction rate constant rather than the affinity between lipase and propionic acid
compared with untreated lipase. The bio-imprinting treatment of lipase is found to be very effective for the yield and kinetics in solvent-free esterification.
This work is licensed under a Creative Commons Attribution 4.0 International License
Itinerant-localized dual character of a strongly-correlated superfluid Bose gas in an optical lattice
We investigate a strongly-correlated Bose gas in an optical lattice.
Extending the standard-basis operator method developed by Haley and Erdos to a
boson Hubbard model, we calculate excitation spectra in the superfluid phase,
as well as in the Mott insulating phase, at T=0. In the Mott phase, the
excitation spectrum has a finite energy gap, reflecting the localized character
of atoms. In the superfluid phase, the excitation spectrum is shown to have an
itinerant-localized dual structure, where the gapless Bogoliubov mode (which
describes the itinerant character of superfluid atoms) and a band with a finite
energy gap coexist. We also show that the rf-tunneling current measurement
would give a useful information about the duality of a strongly-correlated
superfluid Bose gas near the superfluid-insulator transition.Comment: 10 pages, 4 figure
The X-ray Structure of A399 and A401: A Pre-Merging Cluster Pair
We present {\em ASCA} results of the pair clusters A399 and A401. The region
between the two clusters exhibits excess X-rays over the value expected with a
simple superposition of the two clusters. We see, however, no temperature rise
at the merging front; the temperature is near the average of those in the inner
regions of the two clusters. These indicate that the two clusters are really
interacting but it is not strong at present.
The inner regions of the two clusters show no radial variations of
temperature, abundance and absorption values. We set upper-limits of mass
deposition rate of cooling flow to be and
for A399 and A401, respectively. A hint of
azimuthal variation of the temperature is also found.Comment: 17 pages, 13 postscript figures, 2 external tables, accepted for
publication in PAS
Evaluation of scanning earth sensor mechanism on engineering test satellite 4
The results of the analysis and the evaluation of flight data obtained from the horizon sensor test project are described. The rotary mechanism of the scanning earth sensor composed of direct drive motor and bearings using solid lubricant is operated satisfactorily. The transmitted flight data from Engineering Test Satellite IV was evaluated in comparison with the design value
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