The plasma chaotic system is a dissipative dynamical system modeled by a parametric plasma instability arising from the interaction of the whistler and ion acoustic waves with the plasma oscillation ...near the lower hybrid resonance. The amplitudes of these three oscillations obey a three-dimensional system of ordinary differential equations that exhibits chaos for certain parameter values. Besides the maximal Lyapunov exponent technique, a generalized-competitive-mode (GCM) technique has been proposed to evaluate parameter values associated with chaos. A mechanical analysis has also been proposed to reveal the mechanisms underlying the different dynamical modes including chaos. In a series of comparisons between the GCM analysis and mechanical analysis, chaos for the plasma chaotic system is determined. The mechanism and causes by which the plasma chaotic system produces different dynamical behaviors are interpreted. Furthermore, using the whistler-parameter variation of the Casimir function and Casimir power for the plasma system, the generating mechanisms of the different orbital modes and the different levels of chaos are uncovered.
•Comparisons of generalized competitive mode method and mechanical analysis method for plasma system are performed.•Mechanism plasma system dynamics is interpreted using mechanical method than the former method.•Using Casimir power for the plasma system, the mechanism of generating different orbital modes, specially chaos, is uncovered.
•The polyethylenimine acted as both a grafting agent and a reductant of graphene oxide.•A highly sensitive competitive melamine immunosensor.•The polyethyleneimine functionalized graphene increased ...the sensitivity of the sensor.•The gold nanoparticles increased the sensitivity of the sensor.
Branched polyethyleneimine functionalized reduced graphene oxide (BPEIGn) was prepared by a one-step reaction, catalyzed by NaOH, using branched polyethyleneimine (BPEI) and graphene oxide (GO) without reductant hydrazine hydrate or sodium borohydride. The branched polyethylenimine acted as both a grafting agent and a reducing agent of GO. An competitive electrochemical immunosensor based on the Au/sodium mercaptopropanesulfonate/BPEIGn/gold nanoparticles/melamine (Au/MPS/BPEIGn/AuNPs/Mel) modified electrode was constructed for the determination of melamine. The double amplification of BPEIGn and AuNPs increased the sensitivity of the sensor. The melamine was detected by differential pulse voltammetry (DPV) in buffer solution (pH 7.4) containing K3(Fe(CN)6/K4Fe(CN)6. Under optimized conditions, the proposed melamine immunosensor showed a linear relationship in the concentration range of 1 × 10−6 to 1 μM, with a detection limit of 2.66 × 10−7 μM.
We have investigated the role of competitive mode for the generation of chaotic behavior in a financial dynamical system. Such type of events are very important in the light of stock market crush or ...volatile behavior. The competitive mode is a good approach other than the fixed point analysis. The character of mode frequencies and the attractor is analyzed numerically . Also, using an analytical method and Lagrange optimization, we were able to calculate the ultimate bound of the chaotic financial system. The method we have presented is simpler and more accurate than other methods that implicitly calculate the final boundary. The estimation of the ultimate bound can be used to study chaos synchronization. Numerical simulations illustrate the analytical results.
Mechanism for the generation of attractor in nonlinear systems with hidden attractor is still not understood completely. Since such systems do not possess all the requisite properties related to ...fixed points (sometimes they do not possess any fixed point at all), it is really difficult to apply usual logic for attractor generation. Under these circumstances we have applied the recent concept of competitive modes to such nonlinear systems. We show that a reasonable explanation can be obtained in this framework when these modes operate in a slightly different manner. In this connection we have introduced a new quantitative measure of competitiveness through the correlation between any two mode functions. Further analysis leads us to topological study of the various periodic and chaotic states with the help of symbolic dynamics and template structure.
► A potent inhibitor of dengue protease with IC50 of 0.91±0.05μM has been identified. ► The compound is an 8-hydroxyquinoline containing two aryl substitutions at 7 position. ► Kinetic analysis and ...molecular modeling support competitive mode of inhibition.
Four serotypes of dengue virus (DENV1–4), mosquito-borne members of Flaviviridae family cause frequent epidemics causing considerable morbidity and mortality in humans throughout tropical regions of the world. There is no vaccine or antiviral therapeutics available for human use. In a previous study, we reported that compounds containing the 8-hydroxyquinoline (8-HQ) scaffold as inhibitors of West Nile virus serine protease. In this study, we analyzed potencies of some compounds with (8-HQ)-aminobenzothiazole derivatives for inhibition of DENV2 protease in vitro. We identified analogs 1–4 with 2-aminothiazole or 2-aminobenzothiazole scaffold with sub-micromolar potencies (IC50) in the in vitro protease assays. The kinetic constant (Ki) for the most potent 8-HQ-aminobenzothiazole inhibitor (compound 1) with an IC50 value of 0.91±0.05μM was determined to be 2.36±0.13μM. This compound inhibits the DENV2 NS2B/NS3pro by a competitive mode of inhibition.
Three flavonoids derived from the leaves of
Jacq. were identified as chrysoeriol (1), luteolin-7-
-glucopyranoside (
), and isorhamnetin-7-
-glucopyranoside (
). They had IC
values of 11.6±2.9, ...14.4±1.5, and 42.7±3.5 µg/mL against soluble epoxide hydrolase (sEH), respectively. The three inhibitors (1-3) were found to non-competitively bind into the allosteric site of the enzyme with K
values of 10.5±3.2, 11.9 ±2.8 and 38.0±4.1 µg/mL, respectively. The potential inhibitors 1 and 2 were located at the left edge ofa U-tube shape that contained the enzyme active site. Additionally, we observed changes in several factors involved in the binding of these complexes under 300 K and 1 bar. Finally, it was confirmed that each inhibitor,
and
, could be complexed with sEH by the "induced fit" and "lock-and-key" models.
A procedure, we call it generalized competitive mode (GCM), is proposed to estimate the parameter regimes of chaos in nonlinear systems by implementing a mathematical version of mode competition. The ...idea is that for a system to be chaotic there must exist at least two GCMs in the system. The Lorenz system and a thin plate in flow-induced vibrations system are analyzed to find chaotic regimes by this procedure.
This is a study of the interaction of 23 kinds of amino acids, peptides and their analogues with Os
(II) at different pD values. Experiments show that in acidic conditions, the carboxyl group in ...amino acids can coordinate with Os
(II), and there exists H–D coupling of the dihydrogen of the probe with D
2O in strongly acidic conditions, N does not coordinate with Os
(II); In alkaline conditions, the carboxyl group can coordinate with Os, and the coordinating species have trans and cis isomers, and the trans isomer can convert to cis with time; N of –NH
2– in α-amino group can coordinate with Os
(II) while that in γ-amino-
n-butyric acid cannot do that. Since the target of some anti tumor agents are nucleic acids and proteins, we demonstrate a competitive mode to study how the anti tumor complex Me
2SnCl
2 binds to amino acid Ala, and the minimum binding amount and formation constant of the metal anti tumor metal complexes binding with amino acid are also obtained.
In order to investigate the binding sites and the amount of binding of a number of anti-tumor metal complexes (cisplatin, Cp
2TiCl
2 and (CH
3)
2SnCl
2) to target molecule DNA mononucleotides in ...aqueous solution, a
1H NMR recognition probe,
trans
-en
2Os(η
2-H
2)(CF
3SO
3)(CF
3SO
3), was used in a competitive mode. The minimum percentages of binding of anti-tumor metal complexes to different sites of dGMP were also determined.
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