Human Milk Warming Temperatures Using a Simulation of Currently Available Storage and Warming Methods.

Human milk handling guidelines are very demanding, based upon solid scientific evidence that handling methods can make a real difference in infant health and nutrition. Indeed, properly stored milk maintains many of its unique qualities and continues to be the second and third best infant feeding alternatives, much superior to artificial feeding. Container type and shape, mode of steering, amount of air exposure and storage temperature may adversely affect milk stability and composition. Heating above physiological temperatures significantly impacts nutritional and immunological properties of milk. In spite of this knowledge, there are no strict guidelines regarding milk warming. Human milk is often heated in electrical-based bottle warmers that can exceed 80°C, a temperature at which many beneficial human milk properties disappear. High temperatures can also induce fat profile variations as compared with fresh human milk. In this manuscript we estimate the amount of damage due to overheating during warming using a heat flow simulation of a regular water based bottle warmer. To do so, we carried out a series of warming simulations which provided us with dynamic temperature fields within bottled milk. We simulated the use of a hot water-bath at 80°C to heat bottled refrigerated milk (60 ml and 178 ml) to demonstrate that large milk portions are overheated (above 40°C). It seems that the contemporary storage method (upright feeding tool, i.e. bottle) and bottle warming device, are not optimize to preserve the unique properties of human milk. Health workers and parents should be aware of this problem especially when it relates to sick neonates and preemies that cannot be directly fed at the breast.

Three-dimensional simulations of liquid bridges between two cylinders: forces, energies, and torques.

We present numerical simulations of three-dimensional liquid bridges between two identical smooth and chemically homogeneous cylinders held at a fixed distance and angle one with respect to the other. Despite the limited range of parameters studied, an analysis of resultant forces, energies, and torques reveals a rich level of detail. For large enough separations between the cylinders, the bridges appear symmetric and stable in shape and are found to yield a negligible torque on the cylinders. The force of adhesion is found to be positive in this case (the cylinders are attracted one to the other). A reduction in the distance between the cylinders reveals different behavior depending on the particular value of the set of parameters considered. For example, it appears that while relatively low contact angle systems favor attractive (positive) forces and stable symmetric bridges for small separation distances, larger contact angles lead to the coexistence of stable asymmetric and (apparently) unstable symmetric solutions, mostly (and respectively) associated with near-zero and negative (repulsive) forces of adhesion. In addition, while the larger values of contact angles studied here (90 degrees, 110 degrees) are associated with barely detectable torques, smaller values of contact angle are found to be associated with torques acting to rotate cylinders into a position where they are parallel one with respect to the other.