Lagrangian Coherent Structures for Design Analysis of Revolving Doors.

Room air flow and air exchange are important aspects for the design of energy-efficient buildings. As a result, simulations are increasingly used prior to construction to achieve an energy-efficient design. We present a visual analysis of air flow generated at building entrances, which uses a combination of revolving doors and air curtains. The resulting flow pattern is challenging because of two interacting flow patterns: On the one hand, the revolving door acts as a pump, on the other hand, the air curtain creates a layer of uniformly moving warm air between the interior of the building and the revolving door. Lagrangian coherent structures (LCS), which by definition are flow barriers, are the method of choice for visualizing the separation and recirculation behavior of warm and cold air flow. The extraction of LCS is based on the finite-time Lyapunov exponent (FTLE) and makes use of a ridge definition which is consistent with the concept of weak LCS. Both FTLE computation and ridge extraction are done in a robust and efficient way by making use of the fast Fourier transform for computing scale-space derivatives.

Block of a mitochondrial-mediated apoptotic pathway in Tax-expressing murine fibroblasts.

Although the viral transactivator Tax has been established as an essential effector of HTLV-I-mediated oncogenesis, its exact role(s) in the pathogenesis of HTLV-I-associated diseases, which include both a neurodegenerative pathology and leukemia/lymphoma, remains to be clarified. It was recently advanced that dysregulation of the apoptotic process can lead to pathophysiological changes which result in either degenerative diseases or cancer. As the apoptotic potential of Tax is still debated, we addressed this question by testing the susceptibility of Tax(+) and Tax(-) murine fibroblasts to apoptosis under conditions of growth factor withdrawal or treatment with TNFalpha, which trigger apoptosis through different pathways, i.e., mitochondrial and receptor-mediated pathways, respectively. Results showed that Tax-expressing cells are protected from apoptotic death induced by serum deprivation but are sensitive to TNFalpha-mediated apoptosis, suggesting that Tax expression has different effects on cell death, depending on the apoptotic stimulus used. Analysis of the mechanism(s) involved in the resistance to serum depletion-induced apoptosis indicated that Tax(+) cells do not undergo release of cytochrome c from the mitochondrial intermembrane space or redistribution of Bax from the cytosol to mitochondria, two phenomena critical to the mitochondrial apoptotic pathway.