Profile of cabanossi made with exotic meats and olive oil

The effect of olive oil inclusion on the chemical and sensory characteristics in cabanossi made with ostrich and warthog meat was investigated. Ostrich meat from soybean oilcake (SBOC) and cottonseed oilcake dietary inclusion levels (CSOC), and olive oil were included at three levels (0%, 1% and 2%) resulting in six treatments. The fat content in the cabanossi increased with increasing levels of oil inclusion but were all <10%, which allows it to be classified as a low fat meat product. Total monounsaturated fatty acids in the cabanossi increased whilst total saturated fatty acids and total polyunsaturated fatty acids decreased as olive oil increased. The SBOC cabanossi had a lower fat and higher crude protein content. The inclusion of olive oil at 2% resulted in a cabanossi with increased tenderness, juiciness and cured red meat colour, all factors that appeal to the consumer, while the overall flavour descriptors were not adversely affected by the inclusion of olive oil.

Bifurcations and degenerate periodic points in a three dimensional chaotic fluid flow

Analysis of the periodic points of a conservative periodic dynamical system uncovers the basic kinematic structure of the transport dynamics and identifies regions of local stability or chaos. While elliptic and hyperbolic points typically govern such behaviour in 3D systems, degenerate (parabolic) points also play an important role. These points represent a bifurcation in local stability and Lagrangian topology. In this study, we consider the ramifications of the two types of degenerate periodic points that occur in a model 3D fluid flow. (1) Period-tripling bifurcations occur when the local rotation angle associated with elliptic points is reversed, creating a reversal in the orientation of associated Lagrangian structures. Even though a single unstable point is created, the bifurcation in local stability has a large influence on local transport and the global arrangement of manifolds as the unstable degenerate point has three stable and three unstable directions, similar to hyperbolic points, and occurs at the intersection of three hyperbolic periodic lines. The presence of period-tripling bifurcation points indicates regions of both chaos and confinement, with the extent of each depending on the nature of the associated manifold intersections. (2) The second type of bifurcation occurs when periodic lines become tangent to local or global invariant surfaces. This bifurcation creates both saddle-centre bifurcations which can create both chaotic and stable regions, and period-doubling bifurcations which are a common route to chaos in 2D systems. We provide conditions for the occurrence of these tangent bifurcations in 3D conservative systems, as well as constraints on the possible types of tangent bifurcation that can occur based on topological considerations.

Mixing of discontinuously deforming media

Mixing of materials is fundamental to many natural phenomena and engineering applications. The presence of discontinuous deformations-such as shear banding or wall slip-creates new mechanisms for mixing and transport beyond those predicted by classical dynamical systems theory. Here, we show how a novel mixing mechanism combining stretching with cutting and shuffling yields exponential mixing rates, quantified by a positive Lyapunov exponent, an impossibility for systems with cutting and shuffling alone or bounded systems with stretching alone, and demonstrate it in a fluid flow. While dynamical systems theory provides a framework for understanding mixing in smoothly deforming media, a theory of discontinuous mixing is yet to be fully developed. New methods are needed to systematize, explain, and extrapolate measurements on systems with discontinuous deformations. Here, we investigate "webs" of Lagrangian discontinuities and show that they provide a template for the overall transport dynamics. Considering slip deformations as the asymptotic limit of increasingly localised smooth shear, we also demonstrate exactly how some of the new structures introduced by discontinuous deformations are analogous to structures in smoothly deforming systems.

Scalar dispersion in a periodically reoriented potential flow: acceleration via Lagrangian chaos

Although potential flows are irrotational, Lagrangian chaos can occur when these are unsteady, with rapid global mixing observed upon flow parameter optimization. What is unknown is whether Lagrangian chaos in potential flows results in accelerated scalar dispersion, to what magnitude, how robustly, and via what mechanisms. We consider scalar dispersion in a model unsteady potential flow, the Lagrangian topology of which is well understood. The asymptotic scalar dispersion rate q and corresponding scalar distribution (strange eigenmode) are calculated over the flow parameter space Q for Peclét numbers Pe=10{1}-10{4}. The richness of solutions over Q increases with Pe, with pattern mode locking, symmetry breaking transitions to chaos and fractally distributed maxima observed. Such behavior suggests detailed global resolution of Q is necessary for robust optimization, however localization of local optima to bifurcations between periodic and subharmonic eigenmodes suggests novel efficient means of optimization. Acceleration rates of 150 fold at Pe=10{4} are observed; significantly greater than corresponding values for chaotic Stokes flows, suggesting significant scope for dispersion acceleration in potential flows in general.

Lagrangian topology of a periodically reoriented potential flow: symmetry, optimization, and mixing

Scalar transport in closed potential flows is investigated for the specific case of a periodically reoriented dipole flow. Despite the irrotational nature of the flow, the periodic reorientations effectively create heteroclinic and/or homoclinic points arising from the joining of stable and unstable manifolds. For scalar advection, Lagrangian chaos can be achieved with breakdown of the regular Hamiltonian structure, which is governed by symmetry conditions imposed by the dipole flow. Instability envelopes associated with period-doubling bifurcations of fixed points govern which regions of the flow control parameter space admit global chaos. These regions are further refined via calculation of Lyapunov exponents. These results suggest significant scalar transport enhancement is possible within potential flows, given appropriate programming of stirring protocols.

Analytical modeling and numerical simulation of forces in an endoluminal graft

PURPOSE

To utilize mathematical analysis and computational fluid dynamics (CFD) to investigate the forces acting within the pressurized aorta and upon a stent-graft and how these forces may affect the ongoing performance of the stent-graft.

METHODS

Analytical force balance analysis and CFD simulations using the Fluent code were used to mimic blood flow through a bifurcated stent-graft in a person at rest. Steady-state blood flow was assumed in which the inlet pressure approximated the mean blood pressure (100 mm Hg) and the blood flow velocity was an approximation of the peak systolic flow rate (0.6 m/s). Two sizes of endoluminal grafts were analyzed: the larger graft had an inlet diameter of 3 cm and outlet diameters of 1 cm; the smaller graft diameters measured 2.4 cm proximally and 1.2 cm distally. The endografts were studied in 2 configurations: with the limbs straight and with one bent.

RESULTS

For the larger graft model, the normal peak blood flow induced a downward force of 7 to 9 N on the bifurcated grafts. Bending one of the limbs of the graft produced a sideways force of 1.3 N. For the smaller endograft, the downward force was in the range of 3.1 to 5.1 N and the sideways force on a curved limb was approximately 1.5 N. The magnitude of the forces given by the analytical formulae and the CFD results agreed to within 2 significant figures.

CONCLUSIONS

These results suggest that the downward force on a bifurcated stent-graft, which may exceed the force required to dislodge it when relying on radial attachment alone, is determined mostly by the proximal graft diameter. Curvature of the graft limbs creates an additional sideways force that works to displace the distal limbs of the graft from the iliac arteries.

[Acute renal failure as a complication of cholera]

We present a 72-year-old man who had episodes of severe, acute renal failure during severe attacks of diarrhea caused by Vibrio cholerae. Patterns of acute tubular necrosis and tubulointerstitial nephritis developed following hypotension and decrease in renal blood flow, causing secondary renal ischemia. There was severe dehydration with profound hypovolemia and infection. The clinical picture included fever, weakness, arthralgia, pedal edema, mild bilateral pleural effusions, anemia, leukocytosis, azotemia with a maximum of 330 mg/dl of urea, creatine to a maximum of 9.8 mg/dl, hypoproteinemia, severe metabolic acidosis, marked increase in lactate dehydrogenase (LDH) and creatine phosphokinase (CPK), microscopic hematuria, sterile leukocyturia, normoglycemic glucosuria and phosphaturia with diminished tubular reabsorption of phosphorus. A short oliguric phase was followed by a polyuric phase lasting about 10 days, and glomerular and tubular function became normal after about 3 weeks. Treatment was by intensive infusions of fluids, electrolytes, sodium bicarbonate, salt-free albumin and antibiotics. To the best of our knowledge, this renal complication of cholera has not yet been described in Israel.