Vascular tissue 306 Subject

The mechanical behavior and, as a consequence, mechanical properties of its materials are key factors in vascular tissue engineering graft design. The vascular environment is subject to cycfic pressure imposed by the heart [24], which also influences the behavior of tissues and cells. The implantation of grafts or prostheses interrupts... 

Kimball et al. (1998) developed a method to investigate bear forage selection in the field because of the difficulty in obtaining stimuli, as well as subjects that adequately reflect conditions present under normal conditions. First, samples of vascular tissue were collected from preferred trees and rejected trees. Trees where bears had removed more than 2500 cm of the bark were considered to be preferred, while trees with less than 250 cm of the bark removed were considered to have been sampled and then rejected. Trees with no evident foraging marks were not sampled since it could not be ascertained whether they had been encountered by a foraging bear. Chemical assays then were conducted to quantify the carbohydrates and terpenoids within these samples. 

Dermal absorption, the process by which a substance is transported across the skin and taken up into the living tissue of the body (USEPA, 1992), is a complex process. The skin is a multilayered biomembrane with particular absorption characteristics. It is a dynamic, living tissue and as such its absorption parameters are susceptible to constant changes. Upon contact with the skin, a portion of the substance can penetrate into the non-viable stratum comeum and may subsequently reach the viable epidermis, the dermis and, ultimately, the vascular network. During the absorption process, the compound may be subject to biotransformafion (Noonan and Wester, 1989). The stratum comeum provides the skin its greatest barrier function against hydrophilic compounds, whereas the viable epidermis is most resistant to highly lipophilic compounds (Flynn, 1985). 

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