3,832 research outputs found
Efficient production of pullulan by Aureobasidium pullulans grown on mixtures of potato starch hydrolysate and sucrose
AbstractPullulan is a natural exopolysaccharide with many useful characteristics. However, pullulan is more costly than other exopolysaccharides, which limits its effective application. The purpose of this study was to adopt a novel mixed-sugar strategy for maximizing pullulan production, mainly using potato starch hydrolysate as a low-cost substrate for liquid-state fermentation by Aureobasidium pullulans. Based on fermentation kinetics evaluation of pullulan production by A. pullulans 201253, the pullulan production rate of A. pullulans with mixtures of potato starch hydrolysate and sucrose (potato starch hydrolysate:sucrose=80:20) was 0.212h−1, which was significantly higher than those of potato starch hydrolysate alone (0.146h−1) and mixtures of potato starch hydrolysate, glucose, and fructose (potato starch hydrolysate:glucose:fructose=80:10:10, 0.166h−1) with 100gL−1 total carbon source. The results suggest that mixtures of potato starch hydrolysate and sucrose could promote pullulan synthesis and possibly that a small amount of sucrose stimulated the enzyme responsible for pullulan synthesis and promoted effective potato starch hydrolysate conversion effectively. Thus, mixed sugars in potato starch hydrolysate and sucrose fermentation might be a promising alternative for the economical production of pullulan
Biorealistic Implementation of Synaptic Functions with Oxide Memristors through Internal Ionic Dynamics
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/112305/1/adfm201501427.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/112305/2/adfm201501427-sup-0001-S1.pd
Relativistic Correction to J/\psi Production at Hadron Colliders
Relativistic corrections to the color-singlet J/\psi hadroproduction at the
Tevatron and LHC are calculated up to O(v^2) in nonrelativistic QCD (NRQCD).
The short distance coefficients are obtained by matching full QCD with NRQCD
results for the subprocess g+g\to J/\psi+g. The long distance matrix elements
are extracted from observed J/\psi hadronic and leptonic decay widths up to
O}(v^2). Using the CTEQ6 parton distribution functions, we calculate the LO
production cross sections and relativistic corrections for the process
p+\bar{p}(p)\to J/\psi+X at the Tevatron and LHC. We find that the enhancement
of O(v^2) relativistic corrections to the cross sections over a wide range of
large transverse momentum p_t is negligible, only at a level of about 1 %. This
tiny effect is due to the smallness of the correction to short distance
coefficients and the suppression from long distance matrix elements. These
results indicate that relativistic corrections can not help to resolve the
large discrepancy between leading order prediction and experimental data for
J/\psi production at the Tevatron.Comment: 9 pages, 5 figure
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