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In this paper we investigate the following fractional order in time integrodifferential problem D t α u (t) + A u (t) = f (t , u (t)) + ∫ − ∞ t k (t − s) g (s , u (s)) d s , t ∈ R. Here, D t α is the Caputo derivative. We obtain results on the existence and uniqueness of (ω , c) -periodic mild solutions assuming that −A generates an analytic semigroup on a Banach space X and f, g, and k satisfy suitable conditions. Finally, an interesting example that fits our framework is given. [ABSTRACT FROM AUTHOR]

In this paper, we prove the stability results for measure differential equations, considering more general conditions under the Lyapunov functionals and concerning the functions f and g. Moreover, we prove these stability results for the dynamic equations on time scales, using the correspondence between the solutions of these last equations and the solutions of the measure differential equations. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the boundedness results for measure differential equations. In order to obtain our results, we use the correspondence between these equations and generalized ODEs. Furthermore, we prove our results concerning boundedness of solutions for dynamic equations on time scales, using the fact that these equations represent a particular case of measure differential equations. [ABSTRACT FROM AUTHOR]

Abstract The degradation of pesticide diuron has been explored by photoelectrocatalysis (PEC) under visible light illumination using two different WO 3 nanostructures, obtained by anodization of tungsten. The highest degradation efficiency (73%) was obtained for WO 3 nanosheets synthesized in the presence of small amounts of hydrogen peroxide (0.05 M). For that nanostructure, the kinetic coefficient for diuron degradation was 133% higher than that for the other nanostructure (anodized in the presence of fluoride anions). These results have been explained by taking into account the different architecture and dimensions of the two WO 3 nanostructures under study. Highlights • Two different WO 3 nanostructures were fabricated by anodization in two electrolytes. • Photocurrent densities were higher for WO 3 nanosheets formed in the H 2 O 2 solution. • Diuron photoelectrodegradation proceeded through the cleavage of the aromatic ring. • Degradation efficiencies of 73% and mineralization degrees of 50% were obtained. [ABSTRACT FROM AUTHOR]

Progesterone pharmacokinetics were analyzed for plasma hormone concentrations ranging from linear to saturated metabolism in lactating Holstein cows with differing daily milk yields. The adequacy of 2-coupled first-order (bi-exponential equation), hyperbolic (Michaelis-Menten equation), and sigmoidal (Hill equation) kinetic models to describe the experimental progesterone pharmacokinetic profiles was examined on a statistical basis. After nonlinear regression and statistical analysis of the data-fitting capability, a simple one-compartment model based on Hill equation proved to be most adequate. This model indicates an enzyme-catalyzed metabolism of progesterone involving cooperative substrate-binding sites, resulting from allosteric effects that yield a sigmoidal saturation rate curve. Kinetic parameters were estimated for 2 groups of lactating Holstein cows with different daily milk yields. We found, for the first time, a remarkable quantitative agreement of the Hill coefficient value with that reported in pharmacokinetic studies involving cytochrome P450, family 3, subfamily A (CYP3A)-mediated reactions in other mammals, humans included. It seems that positive cooperativity makes enzymes much more sensitive to plasma progesterone concentration, and their activities can undergo significant changes in a narrow range of concentration as characteristic of sigmoidal behavior. Therefore, the values of classical pharmacokinetic parameters, such as the elimination constant, half-life, and clearance rate, were found to be highly dependent on the plasma progesterone concentration. [ABSTRACT FROM AUTHOR]

Bacterial biofilms are important in natural settings, biotechnology, and medicine. However, regulation of biofilm development and its persistence in different niches is complex and only partially understood. One key step during the biofilm life cycle is dispersal, when motile cells abandon the mature biofilm to spread out and colonize new niches. Here, we show that in the model bacterium Bacillus subtilis the general stress transcription factor SigB is essential for halting detrimental overgrowth of mature biofilm and for triggering dispersal when nutrients become limited. Specifically, SigB-deficient biofilms were larger than wild-type biofilms but exhibited accelerated cell death, significantly greater sensitivity to different stresses, and reduced dispersal. Interestingly, the signal detected by SigB to limit biofilm growth was transduced through the RsbP-dependent metabolic arm of the SigB regulatory cascade, which in turn positively controlled expression of SinR, the master regulator of biofilm formation and cell motility. This novel SigB-SinR regulatory circuit might be important in controlling the fitness of biofilms (either beneficial or harmful) in diverse environments. [ABSTRACT FROM AUTHOR]