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71.
Yahya S. Alqahtani Sunil S. More Keerthana R. Ibrahim Ahmed Shaikh Anusha K. J. Veena S. More Francois N. Niyonzima Uday M. Muddapur Aejaz A. Khan 《Molecules (Basel, Switzerland)》2022,27(13)
Enzymes that degrade pectin are called pectinases. Pectinases of microbial origin are used in juice clarification as the process is cost-effective. This study screened a pectinase-producing bacterium isolated from soil and identified as Bacillus subtilis 15A B-92 based on the 16S rRNA molecular technique. The purified pectinase from the isolate showed 99.6 U/mg specific activity and 11.6-fold purity. The molecular weight of the purified bacterial pectinase was 14.41 ± 1 kD. Optimum pectinase activity was found at pH 4.5 and 50 °C, and the enzyme was 100% stable for 3.5 h in these conditions. No enzymatic inhibition or activation effect was seen with Fe2+, Ca2+, or Mg2+. However, a slight inhibition was seen with Cu2+, Mn2+, and Zn2+. Tween 20 and 80 slightly inhibited the pectinase, whereas iodoacetic acid (IAA), ethylenediaminetetraacetate (EDTA), urea, and sodium dodecyl sulfate (SDS) showed potent inhibition. The bacterial pectinase degraded citrus pectin (100%); however, it was inactive in the presence of galactose. With citrus pectin as the substrate, the Km and Vmax were calculated as 1.72 mg/mL and 1609 U/g, respectively. The high affinity of pectinase for its substrate makes the process cost-effective when utilized in food industries. The obtained pectinase was able to clarify orange and apple juices, justifying its application in the food industry. 相似文献
72.
George Amato Vineetha Vasukuttan Danni Harris Lucas Laudermilk Jennifer Lucitti Scott Runyon Rangan Maitra 《Molecules (Basel, Switzerland)》2022,27(17)
Selective modulation of peripheral cannabinoid receptors (CBRs) has potential therapeutic applications in medical conditions, including obesity, diabetes, liver diseases, GI disorders and pain. While there have been considerable efforts to produce selective antagonists or full agonists of CBRs, there has been limited reports on the development of partial agonists. Partial agonists targeting peripheral CBRs may have desirable pharmacological profiles while not producing centrally mediated dissociative effects. Bayer reported that BAY 59-3074 is a CNS penetrant partial agonist of both CB1 and CB2 receptors with efficacy in rat models of neuropathic and inflammatory pain. In this report, we demonstrate our efforts to synthesize analogs that would favor peripheral selectivity, while maintaining partial agonism of CB1. Our efforts led to the identification of a novel compound, which is a partial agonist of the human CB1 (hCB1) receptor with vastly diminished brain exposure compared to BAY 59-3074. 相似文献
73.
The siting and sizing of electrical substations on a rectangular electrical grid can be formulated as an integer programming
problem with a quadratic objective and linear constraints. We propose a novel approach that is based on solving a sequence
of local relaxations of the problem for a given number of substations. Two methods are discussed for determining a new location from
the solution of the relaxed problem. Each leads to a sequence of strictly improving feasible integer solutions. The number
of substations is then modified to seek a further reduction in cost. Lower bounds for the solution are also provided by solving
a sequence of mixed-integer linear programs. Results are provided for a variety of uniform and Gaussian load distributions
as well as some real examples from an electric utility. The results of gams/dicopt, gams/sbb, gams/baron and cplex applied to these problems are also reported. Our algorithm shows slow growth in computational effort with the number of integer
variables. 相似文献
74.
Uday Joshi Muriel Pipelier Jean-Paul Pradère Stéphanie Legoupy Didier Dubreuil 《Tetrahedron letters》2004,45(5):1031-1033
Pyridazine C-nucleosides have been synthesized by [4+2] cycloaddition of alkynyl C-nucleosides with substituted tetrazines. These pyridazines on extrusion of a nitrogen atom afforded novel pyrrole C-nucleosides with good yields. The results of electrochemical and chemical reduction are compared. 相似文献
75.
A. Maitra Marina Dan A. K. Sen K. Bhattacharyya C. K. Sarkar 《International Journal of Infrared and Millimeter Waves》1993,14(3):703-713
Distortion of pulses with pulse widths ranging from 0.1 to 1 ns propagating with carrier frequencies in the range 10–100 GHz through rain filled medium has been estimated considering the absorptive and dispersive effects produced by rain drops on the propagation of millimeter waves. It is found that the rain induced broadening or compression can be quite appreciable for very short pulses in the window region of millimeter wave band under intense and extensive raining conditions. 相似文献
76.
Summary Finite element approximations of the eigenpairs of differential operators are computed as eigenpairs of matrices whose elements involve integrals which must be evaluated by numerical integration. The effect of this numerical integration on the eigenvalue and eigenfunction error is estimated. Specifically, for 2nd order selfadjoint eigenvalue problems we show that finite element approximations with quadrature satisfy the well-known estimates for approximations without quadrature, provided the quadrature rules have appropriate degrees of precision.The work of this author was partially supported by the National Science Foundation under Grant DMS-84-10324 相似文献
77.
In study of polymer-salt complexes usually one is interested in the dc conductivity, which can be extracted from impedance
spectroscopy. However, impedance spectroscopy yields a host of additional information, for example, frequency variation of
the measured admittance or impedance, nature of the Cole-Cole plot and dielectric function. Proper analysis of this information
reveals details of the microstructure and transport processes in the sample. This in turn, will lead to development of better
solid electrolytes with tailor-made properties. The polymer electrolyte PEO-NH4ClO4 shows an interesting variation in its properties in two different regimes, (1) where salt concentration is below ∼ 19 wt.%
and (2) above this concentration. In the present paper we suggest an equivalent circuit incorporating a constant phase element
(CPE), which reproduces the complex admittance behavior at different salt fractions.
Paper presented at the 2nd International Conference on Ionic Devices, Anna University, Chennai, India, Nov. 28–30, 2003. 相似文献
78.
The simplest formulas connecting Jacobi elliptic functions with different modulus parameters were first obtained over two
hundred years ago by John Landen. His approach was to change integration variables in elliptic integrals. We show that Landen’s
formulas and their subsequent generalizations can also be obtained from a different approach, using which we also obtain several
new Landen transformations. Our new method is based on recently obtained periodic solutions of physically interesting non-linear
differential equations and remarkable new cyclic identities involving Jacobi elliptic functions. 相似文献
79.
80.
U. K. Yadav T. Maitra I. Singh 《The European Physical Journal B - Condensed Matter and Complex Systems》2011,84(3):365-370
Thermodynamic properties of the spinless Falicov-Kimball model are studied on a
triangular lattice using numerical diagonalization technique with Monte-Carlo simulation
algorithm. Discontinuous metal-insulator transition is observed at finite temperature.
Unlike the case of square lattice, here we observe that the finite temperature effect is
not able to smear out the discontinuous metal-insulator transition seen in the ground
state. Calculation of specific heat (C
v
)
shows single and double peak structures for different values of parameters like on-site
correlation strength (U), f-electron energy
(E
f
) and temperature. 相似文献