45 research outputs found
Lyso-GM2 Ganglioside: A Possible Biomarker of Tay-Sachs Disease and Sandhoff Disease
To find a new biomarker of Tay-Sachs disease and Sandhoff disease. The lyso-GM2 ganglioside (lyso-GM2) levels in the brain and plasma in Sandhoff mice were measured by means of high performance liquid chromatography and the effect of a modified hexosaminidase (Hex) B exhibiting Hex A-like activity was examined. Then, the lyso-GM2 concentrations in human plasma samples were determined. The lyso-GM2 levels in the brain and plasma in Sandhoff mice were apparently increased compared with those in wild-type mice, and they decreased on intracerebroventricular administration of the modified Hex B. The lyso-GM2 levels in plasma of patients with Tay-Sachs disease and Sandhoff disease were increased, and the increase in lyso-GM2 was associated with a decrease in Hex A activity. Lyso-GM2 is expected to be a potential biomarker of Tay-Sachs disease and Sandhoff disease
The world trade center 9/11 disaster and progressive collapse of tall buildings
The collapse of the World Trade Center buildings on September 11, 2001 posed questions on the stability of tall buildings in fire. Understanding the collapse of
the WTC Towers offers the opportunity to learn useful engineering lessons in order
to improve the design of future tall buildings against fire induced collapse. This paper
extends previous research on the modelling of the collapse of the WTC Towers on
September 11, 2001 using a newly developed ‘‘structures in fire’’ simulation capability
in the open source software framework OpenSees. The simulations carried out are
validated by comparisons with previous work and against the findings from the NIST
investigation, albeit not in the forensic sense. The column ‘‘pull in’’ that triggers the
instability of the structure and leads to collapse is explained. The collapse mechanisms
of generic composite tall buildings are also examined. This is achieved through carrying out a detailed parametric study varying the relative stiffness of the column and the floors. The two main mechanisms identified in previous research (weak and strong floor) are reproduced and criteria are established on their occurrence. The analyses performed revealed that the collapse mechanism type depended on the bending
stiffness ratio and the number of floors subjected to fire and that the most probable
type of failure is the strong floor collapse. The knowledge of these mechanisms is
of practical use if stakeholders wish to extend the tenability of a tall building structure
in a major fire.Professor Jose Torero and the Open-Sees team at PEER, UC Berkele