Design of Nanostructured Lipid Carriers Containing Cymbopogon martinii (Palmarosa) Essential Oil against Aspergillus nomius

Palmarosa essential oil (PEO) is an alternative to synthetic fungicides to control the contamination by food-deteriorating fungi, such as Aspergillus nomius. Nonetheless, the low long-term stability and volatility hamper its utilization. Thus, this study aimed to develop nanostructured lipid carriers (NLCs) containing PEO to improve its stability and consequently prolong the activity against A. nomius. A mixture design was applied to find the best preparation conditions for antifungal activity. The characterization analyses included size measurements, zeta potential (ζ-potential), entrapment efficiency (EE), and antifungal activity (by inhibition of mycelial growth (IMG) and/or in situ test (pre-contaminated Brazil nuts) tests). The nanocarriers presented particle sizes smaller than 300 nm, homogeneous size distribution, ζ-potential of −25.19 to −41.81 mV, and EE between 73.6 and 100%. The formulations F5 and F10 showed the highest IMG value (98.75%). Based on the regression model, three optimized formulations (OFs) were tested for antifungal activity (IMG and in situ test), which showed 100% of inhibition and prevented the deterioration of Brazil nuts by A. nomius. The preliminary stability test showed the maintenance of antifungal activity and physicochemical characteristics for 90 days. These results suggest a promising system as a biofungicide against A. nomius.     

Microcanonical Monte Carlo study of one dimensional self-gravitating lattice gas models

In this study we present a microcanonical Monte Carlo investigation of one dimensional (1 ? d) self-gravitating toy models. We study the effect of hard-core potentials and compare to the results obtained with softening parameters and also the effect of the topology on these systems. In order to study the effect of the topology in the system we introduce a model with the symmetry of motion in a line instead of a circle, which we denominate as 1 /r model. The hard-core particle potential introduces the effect of the size of particles and, consequently, the effect of the density of the system that is redefined in terms of the packing fraction of the system. The latter plays a role similar to the softening parameter ? in the softened particles’ case. In the case of low packing fractions both models with hard-core particles show a behavior that keeps the intrinsic properties of the three dimensional gravitational systems such as negative heat capacity. For higher values of the packing fraction the ring model behaves as the potential for the standard cosine Hamiltonian Mean Field model while for the 1 /r model it is similar to the one-dimensional systems. In the present paper we intend to show that a further simplification level is possible by introducing the lattice-gas counterpart of such models, where a drastic simplification of the microscopic state is obtained by considering a local average of the exact N-body dynamics.     

Asymptotic behavior of maximum likelihood estimators in a branching diffusion model

In this paper the consistency and asymptotic normality of maximum-likelihood estimations for a super-critical branching diffusion model are obtained under certain conditions on its drift, variance and reproduction law. We proceeded by first studying the limit behavior of the Fisher information measure and related processes, and then verifying conditions established in Barndorff-Nielsen and Sørensen (Int stat Rev 62:133–165, 1994). This in turn uses the Martingale Law of Large Numbers as well as the Martingale Central Limit Theorem.     

Continuous chromatographic separation of a baclofen precursor (N-Boc-4-[p-chloro-phenyl]-2-pyrrolidone) in a simulated moving bed using a polysaccharide carbamate as chiral stationary phase

Liquid chromatography is known as one of the most flexible, efficient and cost-effective methods to resolve racemic mixture in order to attend the growing demand of the pharmaceutical industry for pure enantiomeric compounds. Cellulose tris(3,5-dimethylphenylcarbamate) is frequently used as a stationary phase for enantiomeric separations because of its attractive properties, including high enantioselectivity, high loading capacity and good mechanical stability. In this study, we investigated the usefulness of cellulose tris(3,5-dimethylphenylcarbamate) as the stationary phase and of ethanol and hexane mixtures as the mobile phases for the chromatographic separation of potential pharmaceutical intermediates. Using adsorption equilibrium data, we determined the optimal operational conditions for the separation of the N-Boc-4-[p-chloro-phenyl]-2-pyrrolidone enantiomers - a baclofen precursor - in a semi-preparative scale simulated moving bed unit. This unit was used to obtain high purity enantiomers on a scale of 1g/day. The outlet streams were analyzed by an on-line system that consisted of a UV-vis spectrophotometric unit, a polarimeter, and HPLC. Enantiomeric purities of up to 97% were obtained for the raffinate stream and up to 90% for the extract stream.     

Ultrasound promoted synthesis of 5-hydroxy-5-trihalomethyl-4,5-dihydroisoxazoles and beta-enamino trihalomethyl ketones in water

A convenient method for the preparation of 5-hydroxy-5-trihalo-4,5-dihydroisoxazoles and beta-enamino trihalomethyl ketones, from the reaction of 1,1,1-trihalo-4-alkoxy-3-alken-2-ones with hydroxylamine and anilines, respectively, using water as solvent and under ultrasound irradiation is reported.     

On a Schrödinger equation with periodic potential and critical growth in \mathbb{R}^{2}

The main purpose of this paper is to establish the existence of a solution of the semilinear Schr?dinger equation

Residual methods for the large-scale matrix pth root and some related problems

The problem of finding the pth root of a matrix has received special attention in the last few years. Standard approaches for this problem include and combine some variations of Newton’s method, which in turn involve matrix factorizations that, in general, are not suitable for large-scale problems. Motivated by some recently developed low-cost iterative schemes for nonlinear problems, we consider and analyze specialized residual methods that only require a few matrix-matrix products per iteration, and hence are suitable for the large-scale case. As a by-product we also discuss the advantages of residual methods for general nonlinear problems whose variables separate. Preliminary and encouraging numerical results are presented for computing pth roots of large-scale symmetric and positive definite matrices, for different values of p.     

A new inversion-free method for a rational matrix equation

Motivated by the classical Newton-Schulz method for finding the inverse of a nonsingular matrix, we develop a new inversion-free method for obtaining the minimal Hermitian positive definite solution of the matrix rational equation X+A^∗X^-1A=I, where I is the identity matrix and A is a given nonsingular matrix. We present convergence results and discuss stability properties when the method starts from the available matrix AA^∗. We also present numerical results to compare our proposal with some previously developed inversion-free techniques for solving the same rational matrix equation.     

Mild solutions for impulsive neutral functional differential equations with state-dependent delay

In this work, we establish the existence of mild solutions for a class of impulsive neutral functional differential equations with state-dependent delay.     

Desingularization of singular Riemannian foliation

Let F{\mathcal{F}} be a singular Riemannian foliation on a compact Riemannian manifold M. By successive blow-ups along the strata of F{\mathcal{F}} we construct a regular Riemannian foliation [^(F)]{\hat{\mathcal{F}}} on a compact Riemannian manifold [^(M)]{\hat{M}} and a desingularization map [^(r)]:[^(M)]? M{\hat{\rho}:\hat{M}\rightarrow M} that projects leaves of [^(F)]{\hat{\mathcal{F}}} into leaves of F{\mathcal{F}}. This result generalizes a previous result due to Molino for the particular case of a singular Riemannian foliation whose leaves were the closure of leaves of a regular Riemannian foliation. We also prove that, if the leaves of F{\mathcal{F}} are compact, then, for each small ${\epsilon >0 }${\epsilon >0 }, we can find [^(M)]{\hat{M}} and [^(F)]{\hat{\mathcal{F}}} so that the desingularization map induces an e{\epsilon}-isometry between M/F{M/\mathcal{F}} and [^(M)]/[^(F)]{\hat{M}/\hat{\mathcal{F}}}. This implies in particular that the space of leaves M/F{M/\mathcal{F}} is a Gromov-Hausdorff limit of a sequence of Riemannian orbifolds {([^(M)]_n/[^(F)]_n)}{\{(\hat{M}_{n}/\hat{\mathcal{F}}_{n})\}}.