Objective: To develop an in vitro digestion method to assess the impact of heat treatment, particle size and presence of oil on the accessibility (available for absorption) of a-and b-carotene in carrots. Design: Raw and cooked carrots were either homogenized or cut into pieces similar to chewed items in size. The carrot samples, with or without added cooking oil, were exposed to an in vitro digestion procedure. Adding a pepsin -HCl solution at pH 2.0 simulated the gastric phase. In the subsequent intestinal phase, pH was adjusted to 7.5 and a pancreatin -bile extract mixture was added. Carotenoids released from the carrot matrix during the digestion were extracted and quantified on highperformance liquid chromatography (HPLC). Results: Three percent of the total b-carotene content was released from raw carrots in pieces. When homogenized (pulped) 21% was released. Cooking the pulp increased the accessibility to 27%. Addition of cooking oil to the cooked pulp further increased the released amount to 39%. The trends for a-carotene were similar to those for b-carotene. Conclusion: The described in vitro digestion method allows a rapid estimation of carotene accessibility in processed carrots, which may reliably predict in vivo behavior.

We prove the existence of a finite extinction time for the solutions of the Dirichlet problem for the total variation flow. For the Neumann problem, we prove that the solutions reach the average of its initial datum in finite time. The asymptotic profile of the solutions of the Dirichlet problem is also studied. It is shown that the profiles are nonzero solutions of an eigenvalue-type problem that seems to be unexplored in the previous literature. The propagation of the support is analyzed in the radial case showing a behaviour entirely different to the case of the problem associated with the p-Laplacian operator. Finally, the study of the radially symmetric case allows us to point out other qualitative properties that are peculiar of this special class of quasilinear equations. © 2002 Elsevier Science (USA)

This paper studies the Cauchy-Dirichlet problem associated with the equation b(u)t -div (IVu-K (b(u))el p-2 (Vu-K (b(u))e)) +g(x,u)--f(t,x). This problem arises in the study of some turbulent regimes: flows of incompressible turbulent fluids through porous media and gases flowing in pipes of uniform cross sectional areas. The paper focuses on the class of bounded weak solutions, and shows (under suitable assumptions) their stabilization, as c, to the set of bounded weak solutions of the associated stationary problem. The existence and comparison properties (implying uniqueness) of such solutions are also investigated. Key words, nonlinear parabolic equations, degenerate parabolic and elliptic equations, stabilization, existence and uniqueness of bounded weak solutions

New supersymmetric partners of the modified Pöschl-Teller and the Dirac's delta well potentials are constructed in closed form. The resulting one-parametric potentials are shown to be interrelated by a limiting process. The range of values of the parameters for which these potentials are free of singularities is exactly determined. The construction of higher order supersymmetric partner potentials is also investigated.

No abstract

No abstract

No abstract

No abstract