Curcumin-Loaded Microspheres Are Effective in Preventing Oxidative Stress and Intestinal Inflammatory Abnormalities in Experimental Ulcerative Colitis in Rats

Curcumin’s role in the treatment of ulcerative colitis (UC) has been proven by numerous studies, but its preventive administration, with the aim of reducing the remission episodes that are characteristic of this disease, must be further investigated. This study investigates the effects of a novel curcumin-loaded polymeric microparticulate oral-drug-delivery system for colon targeting (Col-CUR-MPs) in an experimental model of UC. Male Wistar rats (n = 40) were divided into five groups (n = 8), which were treated daily by oral gavage for seven days with a 2% aqueous solution of carboxymethylcellulose sodium salt (CMCNa) (healthy and disease control), free curcumin powder (reference), Col-CUR-MPs (test) and prednisolone (reference) prior to UC induction by the intrarectal administration of acetic acid (AA), followed by animal sacrification and blood and colonic samples’ collection on the eighth day. Col-CUR-MPs exhibited an important preventive effect in the severity degree of oxidative stress that resulted following AA intrarectal administration, which was proved by the highest catalase (CAT) and total antioxidant capacity (TAC) levels and the lowest nitrites/nitrates (NOx), total oxidative status (TOS) and oxidative stress index (OSI) levels. Biochemical parameter analysis was supported by histopathological assessment, confirming the significant anti-inflammatory and antioxidant effects of this novel colon-specific delivery system in AA-induced rat models of UC. Thus, this study offers encouraging perspectives regarding the preventive administration of curcumin in the form of a drug delivery system for colon targeting.     

Inequality problems with Nonlocally Lipschitz Energy Functional: Existence Results and Applications to Nonsmooth Mechanics

We give an existence result for a double eigenvalue problem in Hemivariational Inequalities whose energetic functional is not locally Lipschitz. It is used a finite dimensional approach based on Kakutani's fixed point theorem.     

Concentration phenomena in nonlinear eigenvalue problems with variable exponents and sign-changing potential

In this paper we establish the concentration of the spectrum in an unbounded interval for a class of eigenvalue problems involving variable growth conditions and a sign-changing potential. We also study the optimization problem for the particular eigenvalue given by the infimum of the associated Rayleigh quotient when the variable potential lies in a bounded, closed and convex subset of a certain variable exponent Lebesgue space.     

Multiple solutions of hemivariational inequalities with area-type term

Hemivariational inequalities containing both an area-type and a non-locally Lipschitz term are considered. Multiplicity results are obtained by means of techniques of nonsmooth critical point theory. Received: December 24, 1998 / Accepted: October 1, 1999     

Qualitative Analysis of Gradient-Type Systems with Oscillatory Nonlinearities on the Sierpi′nski Gasket

Under an appropriate oscillating behavior either at zero or at infinity of the nonlinear data, the existence of a sequence of weak solutions for parametric quasilinear systems of the gradient-type on the Sierpi′nski gasket is proved. Moreover, by adopting the same hypotheses on the potential and in presence of suitable small perturbations, the same conclusion is achieved. The approach is based on variational methods and on certain analytic and geometrical properties of the Sierpi′nski fractal as, for instance, a compact embedding result due to Fukushima and Shima.     

Sublinear eigenvalue problems associated to the Laplace operator revisited

Eigenvalue problems involving the Laplace operator on bounded domains lead to a discrete or a continuous set of eigenvalues. In this paper we highlight the case of an eigenvalue problem involving the Laplace operator which possesses, on the one hand, a continuous family of eigenvalues and, on the other hand, at least one more eigenvalue which is isolated in the set of eigenvalues of that problem.     

Perturbation effects in nonlinear eigenvalue problems

We establish the complete bifurcation diagram for a class of nonlinear problems on the whole space. Our model corresponds to a class of semilinear elliptic equations with logistic type nonlinearity and absorption. Since this problem arises in population dynamics or in fishery or hunting management, we are interested only in situations allowing the existence of positive solutions. The proofs combine elliptic estimates with the method of sub- and super-solutions.     

Optimisation of piezoelectric injection of dopants and drift gas modifiers in transverse ion mobility spectrometry

Novel experimental methods are described for controlling the levels of dopant or drift gas modifier with piezoelectric actuation. The piezoelectric jetting of 2-butanol, acetone, 4-heptanone and dichloromethane was first optimised by applying a fractional factorial experimental design to the waveform required to actuate the dopants. The concentration of dopant entering a transverse ion mobility cell was dynamically controlled by a series of air flows at the interface between the actuator and the ion source, as well as the droplet injection frequency, as defined by the optimised waveform parameters. The optimisation methodology indicated that dwell time and dwell voltage were the most important factors in controlling the process. The optimised approach was then used to deliver varying levels of candidate dopants; 20.5 to 196.6 μg?m^?3 for 2-butanol, 35.4 to 164.3 μg?m^?3 for acetone, 17.8 to 58.2 μg?m^?3 for 4-heptanone and 27.6 to 270.2 μg?m^?3 for dichloromethane. The method enables reactant ion chemistry to be switched in the order of 3 to 5 sec, indicating the potential for introducing multiple dopants at varying concentrations into ion mobility spectrometers. The most volatile material dichloromethane was more difficult to control and the reproducibility and stability of the instrument responses to this compound was not as good as the other less volatile ones. The concept of extending this approach to mixtures and dual use formulations, doping and modification was proposed.